EP3608504A1 - Chisel with a support element with a centring attachment - Google Patents

Abstract

The invention relates to a chisel, in particular a round shank chisel, with a chisel head and a chisel shank, with a support element which has a seat surface on its underside and a centering projection projecting beyond the seat surface, the centering projection having a centering surface which is inclined to the central longitudinal axis of the chisel and which is indirect or passes directly into the seat surface and the support element is broken through along the central longitudinal axis by a receiving bore with an inner diameter D _i for receiving the chisel shank. It is provided that a collar height measured in the direction of the central longitudinal axis between an end of the centering shoulder facing away from the seat surface and the seat surface or between the end of the centering shoulder and an inner end of a recess that is recessed in the support element with respect to the seat surface is designed such that the Ratio between the inner diameter D _i of the receiving bore of the support element and the collar height is less than 8 and / or that the collar height is greater than an axial play of the chisel mounted in a chisel holder.

Description

The invention relates to a chisel, in particular a round shank chisel, with a chisel head and a chisel shank, with a support element which has a seat surface on its underside and a centering projection projecting beyond the seat surface, the centering projection having a centering surface which is inclined to the central longitudinal axis of the chisel and which is indirect or passes directly into the seat surface and the support element is broken along the central longitudinal axis by a receiving bore with an inner diameter D _i for receiving the chisel shank.

The invention further relates to a tool system with a chisel, in particular a round shank chisel, which has a chisel head and a chisel shank, with a support element which has a seat surface on its underside and a centering projection projecting beyond the seat surface, the centering projection extending inclined to the central longitudinal axis of the chisel Has centering surface which merges directly or indirectly into the seat surface, the support element being broken along the central longitudinal axis by a receiving bore with an inner diameter D _i for receiving the chisel shaft, with a chisel holder for receiving the chisel shaft, the chisel holder facing the support element has a wear surface for supporting the seat surface and a centering receptacle for receiving the centering projection of the support element.

Such a chisel or tool system are known from US Pat DE102014104040A1 known. Starting from a cutting element, the diameter of the chisel head increases towards a collar, to which a chisel shaft adjoins. The cylindrical chisel shaft is held in a chuck holder in a holding attachment of a chisel holder by means of an adapter sleeve. The fixation by means of the clamping sleeve allows the chisel to rotate about its central longitudinal axis while an axial movement is blocked. A support element is arranged between the chisel head and the holding attachment, through the central receiving bore of which the chisel shaft is guided. Towards the chisel head, the support element has a recess bordered by an edge, the bottom of which represents a support surface, on which the chisel head rests with a support surface. Towards the chisel holder, the support element forms a seat surface which, towards the center of the support element, merges into a centering surface of a centering projection which runs obliquely to the central longitudinal axis of the chisel. In the transition area between the centering surface and the seat surface, a groove is arranged which has a depth of at least 0.3 mm compared to the seat surface. The top of the holding attachment of the chisel holder is shaped toward the chisel head corresponding to the underside of the support element. It has a wear surface on which the seat surface of the support element rests. The centering projection of the support element is guided radially in a centering receptacle of the holding projection. Due to the wear of the wear surface during the operation of the tool arrangement with the chisel, a bulge is formed on the wear surface of the chisel holder in the area of the groove of the support element, which bulge engages in the groove. An additional lateral guidance of the support element is achieved by this engagement. At the same time, the penetration of debris into the area of the chisel receptacle is at least reduced by the groove and the bead engaging therein, thereby maintaining the rotatability of the chisel and reducing wear.

In order to ensure that the chisel can be rotated about its central longitudinal axis, axial play of the chisel in the chisel holder is desirable. It is for larger ones Chisels are designed to have a larger clearance than for smaller chisels. If the axial play exceeds the height of the centering attachment, the lateral guidance of the support element through the centering attachment is lost. This leads to increased wear on both the support element and the bit holder.

From the DE 60209235 T2 a disc for a rotatable cutting bit is known. The disc has a plurality of ribs on its front facing the chisel head. These can have a curved shape and can be evenly distributed over the circumference of the disk. On the opposite back, evenly distributed recesses can be formed in the disc. Towards a central receiving bore of the disk, the rear side has a centering projection with a bevelled edge that runs inclined to the central longitudinal axis of the disk. When the disk is mounted, this protrudes into a corresponding chamfer, which is arranged all the way around a bit holder of a bit holder, which results in lateral guidance of the disk. The contact surface of the disk is reduced by the ribs and recesses, which leads to improved rotatability of the disk.

With this arrangement too, due to the permissible axial play of the mounted chisel, the lateral guidance of the disk can be lost through the centering projection with the chisel raised to the maximum, which significantly increases the wear on the disk itself and on the chisel holder. In particular, a wobbling movement of the disk which is made possible in this way can lead to uneven wear of the end face of the bit holder, as a result of which it is chamfered and thus wears out more quickly. Furthermore, the rotatability of the chisel can be restricted or blocked in the case of an obliquely worn end face, which leads to rapid and unilateral wear of the chisel. The radially aligned ribs and recesses do not lead to any additional lateral guidance of the disk.

It is therefore an object of the invention to provide a chisel with improved wear behavior. It is a further object of the invention to provide a tool system with such a chisel.

The object of the invention relating to the chisel is achieved in that a collar height measured in the direction of the central longitudinal axis between an end of the centering attachment facing away from the seat surface and the seat surface or between the end of the centering attachment and an inner end of a recess recessed in the support element relative to the seat surface is designed such that the ratio between the inner diameter D _{i of} the receiving bore of the support element and the collar height is less than 8 and / or that the collar height is greater than an axial play of the chisel mounted in a chisel holder. Mounted on a chisel holder, the seat surface of the support element lies on a wear surface of the chisel holder. The centering lug engages in a centering recess molded into the wear surface and thus leads to a radial stabilization of the positions of the support element. If a recess is formed in the seat, an attachment of the chisel holder engages in it. A ratio of less than 8 between the inside diameter D _{i of} the receiving bore of the support element and the collar height ensures sufficient blocking of a lateral movement of the support element. The collar height is preferably chosen to be greater than the maximum axial play expected over the life expectancy of the chisel. The centering lug thus leads to a lateral stabilization of the support element even when the chisel is pulled out of the chisel receptacle within the axial play. As a result, the wear of the support element and the wear surface of the bit holder can be significantly reduced. This applies in particular to an uneven axial load on the support element. In the event of insufficient lateral stabilization of the support element, such an uneven axial load leads to asymmetrical and thus increased wear of the wear surface of the holder. The improved lateral guidance of the support element according to the invention results in a more precise centering of the chisel guided in the receiving bore of the support element, as a result of which asymmetrical wear on the wear surface is avoided or at least reduced. The low wear of the support element and the wear surface, as well as the improved centering of the chisel, stabilize the rotary movement of the chisel. This causes more even wear and tear an increase in tool life. The centering approach, in cooperation with the centering fixture, leads to a labyrinth-like seal. This at least reduces the penetration of debris and dust into the area of the bit holder and bit shaft. The selected ratio of less than 8 between the inside diameter D _{i of} the receiving bore of the support element and the collar height ensures a sufficient seal so that no or only a few foreign substances get into the area of the bit holder and the bit shaft and block the rotary movement of the bit. This reduces the wear on the chisel.

It can preferably be provided that the ratio between the inside diameter D _{i of} the receiving bore and the collar height is less than 7.5, preferably less than 7.0, particularly preferably less than 6.5. If the ratio is less than 7.5, good lateral guidance is achieved even with transverse forces acting directly on the support element, for example through striking material. The ratio of the lateral guidance is further improved by a ratio of less than 7.0, so that the simultaneous action of axially aligned forces which are distributed unevenly over the supporting element and of radially acting transverse forces does not lead to a wobbling movement of the supporting element with the resulting high wear. With a ratio of less than 6.5, sufficient lateral guidance is also achieved towards the end of the service life of the support element and the chisel, if the axial play of the chisel is possibly increased by the wear that has already occurred.

A radially acting guidance of the support element and thus of the chisel with simultaneous good rotatability of the support element and the chisel can be achieved in that the centering projection and / or the recess are arranged all round to the receiving bore.

The lateral guidance of the support element can be further improved in that a plurality of recesses of the same or different depth or at least one recess extending spirally around the centering projection are formed in the seat surface and that the ratio between the inner diameter D _i Receiving hole of the support element and the collar height to one of the recesses or the grooves of the spiral recess, preferably the ratio between the inner diameter D _{i of} the receiving hole and the largest collar height determined to a recess or a groove, is less than 8. The projected area is retained in the axial direction by a plurality of recesses arranged radially next to one another and corresponding approaches of the bit holder engaging in the recesses, but the contact area between the bit holder and the support element in the radial direction is increased. This enables greater transverse forces to be absorbed. At the same time, the contact area between the chisel holder and the support element is increased, as a result of which the surface pressure and consequently also the wear are reduced. The recesses lying next to one another and the lugs engaging therein further improve the sealing effect against penetrating debris material. Due to the ratio of less than 8 between the inside diameter D _{i of} the receiving bore of the support element and the collar height, sufficient radial guidance of the support element and thus of the chisel is achieved even with the support element lifted off the wear surface within the scope of the axial play.

A further improvement of the lateral guidance as well as the sealing and thus the rotatability and the wear of the chisel can be achieved in that a guide web projects beyond the adjacent seat surface at a distance from the centering projection. The guide web advantageously engages in a web receptacle which is embedded in the wear surface of the bit holder and corresponds to the guide web.

The centering lug is advantageously received in a centering receptacle formed in the chisel holder and rotatably supported therein. The guide web integrally formed on the seat surface of the support element then grinds itself into the wear surface of the bit holder that has just been executed during the operation of the bit. In order to achieve sufficient lateral guidance of the support element before the guide web has ground a web receptacle into the bit holder, it can be provided that the recess between the centering projection and the Guide bar is formed and that the centering projection has a greater height than the guide bar compared to the adjacent seat.

An essential requirement for low wear of the chisel, the support element and the chisel holder is the easy and free rotatability of the support element and the chisel about the central longitudinal axis of the chisel. The rotatability can be improved in that transitions between the centering surface, the seat surface, the recess and / or the guide web are straight or rounded. This avoids sharp edges that block the rotation.

Good lateral guidance of the support element can result from the fact that the depth of the recess relative to the seat surface is greater than or equal to 0.3 mm, preferably between 0.3 mm and 2 mm, particularly preferably between 0.5 mm and 1.5 mm. If the recess is selected to be smaller than 0.3 mm, there is no sufficiently pronounced approach for sufficient lateral stabilization of the support element. Recesses down to a depth of 2mm result in a good sealing effect (labyrinth seal) between the shoulder and the recess. If the depth of the recess is chosen between 0.5 mm and 1.5 mm, there is a good combined effect between the seal and the side guide.

Suitable for common bit types, and associated toolholder support elements can be obtained in that the support element has a receiving bore with an inner diameter D _i of 20 mm, and the collar height is greater than 2.5 mm and / or that the supporting element a receiving bore with an inner diameter D _i of 22 mm and the collar height is greater than 2.75 mm and / or that the support element has a receiving bore with an inner diameter D _i of 25 mm and the collar height is greater than 3.125 mm and / or that the supporting element has a receiving bore with an inner diameter D _i of 42 mm and the collar height is greater than 5.25mm. For smaller chisels, for example for fine milling, support elements with an inner diameter D _{i of} the mounting hole of 20mm or 22mm and a collar height of at least 2.5mm or 2.75mm are suitable. For medium chisels Support elements with an inner diameter D _{i of} the mounting hole 25mm and a collar height of 3.125mm are suitable for this size. For large chisels and associated chisel holders, support elements with a 42mm inner diameter D _{i of} the mounting hole and a collar height of at least 5.25mm can be used. With a ratio of less than 8 between the inner diameters D _{i of} the receiving bores of the support elements and the respective collar height, correspondingly higher centering approaches are provided for larger support elements. This ensures that there is sufficient lateral guidance of the support elements in the case of larger chisels with correspondingly greater forces and greater axial play of the chisel.

The object of the invention relating to the tool system is achieved in that a centering height measured in the direction of the central longitudinal axis between an end of the centering receptacle facing away from the wear surface and the wear surface or between the end of the centering receptacle and a maximum point of a shoulder projecting beyond the wear surface is designed such that the ratio between the inner diameter D _{i of} the receiving bore of the support element and the centering height is less than 8 and / or that the collar height is greater than an axial play of the chisel mounted in a chisel holder.

Due to the ratio of less than 8 between the inner diameter D _{i of} the receiving bore of the support element and the centering height, good lateral guidance of the centering shoulder engaging in the centering seat is achieved. If the collar height is greater than the axial play of the chisel mounted in the chisel holder, good lateral guidance is also achieved if the chisel is pulled out of the chisel holder within its maximum permissible axial play and the support element is in the area of the gap formed in this way between the bit head and the bit holder can be adjusted in the axial direction. The required centering height is provided correspondingly larger for larger support elements and thus for larger tool systems. As a result, good lateral guidance of the support element is achieved even with large tool systems with a correspondingly larger permissible axial play of the chisel. At the same time the centering receptacle and the centering projection of the support element engaging therein create a pronounced, labyrinth-like sealing section which at least makes it difficult for foreign bodies to penetrate into the area of the chisel bearing.

Both the lateral guidance and the sealing effect can be improved in that the support element rests with its seating surface on the wear surface of the chisel holder and that at least one shoulder of the chisel holder protruding beyond the wear surface is designed to correspond to a recess of the support element molded into the seating surface and in this protrudes. The approach and correspondingly the recess can be throat-shaped or trapezoidal or multi-stage in different contour sections.

The lateral guidance and the sealing effect can be further improved in that the support element has a guide web that projects beyond the adjacent seat surface and that the bit holder has a web receptacle molded into the wear surface and corresponding to the guide web, into which the guide web projects. Combinations are also conceivable in which the seat surface of the support element has both at least one guide web and at least one recess and the wear surface correspondingly has at least one web receptacle and at least one shoulder.

According to a particularly preferred embodiment variant of the invention, it can be provided that the attachment and / or the web receptacle are attached to the wear surface by means of a shaping process during the manufacture of the bit holder and that the corresponding recess and / or the corresponding guide web are used during operation of the tool system are formed by abrasion of the seat surface and / or that the recess and / or the guide web are attached to the seat surface by a shaping method in the production of the support element and that the corresponding attachment and / or the corresponding web receptacle during the operation of the tool system are formed by abrasion of the wear surface. Only one component, namely the chisel holder or the support element, has to be profiled accordingly during production. The profile then grinds into the opposite component during operation. The grinding process can be carried out over several chisel changes. The harder component is advantageously profiled. The profiling is particularly preferably carried out on the seat surface of the support element. Corresponding lugs and bar receptacles are then ground into the wear surface of the bit holder during operation. Grinding is advantageously carried out during rotational movements of the support element. The support element is guided radially through its centering projection in the centering receptacle of the bit holder.

Figur 1

in einer Seitenansicht ein Werkzeugsystem mit einem Meißel in seiner Montagestellung an einem Meißelhalter,

Figur 2

ein in der Figur 1 mit II. markiertes Detail,

Figur 3

in einer schematischen Darstellung den Verschleiß einer Verschleißfläche eines Meißelhalters bei einem bekannten Stützelement,

Figur 4

in einer seitlichen Schnittdarstellung ein Ausschnitt eines Stützelementes in einer ersten Ausführung und

Figuren 5-14

in schematischen seitlichen Schnittdarstellungen jeweils einen Ausschnitt eines Stützelementes in weiteren Ausführungen.

The invention is explained below with reference to an embodiment shown in the drawings. Show it:

Figure 1

a side view of a tool system with a chisel in its assembly position on a chisel holder,

Figure 2

an Indian Figure 1 detail marked with II.

Figure 3

a schematic representation of the wear of a wear surface of a chisel holder in a known support element,

Figure 4

in a lateral sectional view a section of a support element in a first embodiment and

Figures 5-14

in schematic side sectional views, a section of a support element in further versions.

Figure 1 shows a side view of a tool system according to the prior art with a chisel 10 in its assembly position on a chisel holder 40. The chisel 10, which is designed as a round shank chisel, has a chisel head 13 a chisel tip 14 made of a hard material, for example hard metal. Opposite the chisel tip 14, a cylindrical centering section 12 is formed on the chisel head 13, which merges into a cylindrical chisel shaft 11 via a tapering section 12.1.

The chisel holder 40 has a base part 41, on which a plug-in projection 42 protruding on the underside is formed. The base part 41 also carries a one-piece molded attachment lug 43, into which a chisel receptacle 46 is introduced as a cylindrical bore. The chisel receptacle 46 is designed as a through hole that is open at its two longitudinal ends. The end of the chisel receptacle 46 facing away from the plug-in attachment 42 opens into a cylindrical section 44 of the holding attachment 43. Wear markings 45 in the form of circumferential rings are provided on the outer circumference of the holding attachment 43.

The chisel 10 is held on its chisel shank 11 by means of a fastening sleeve 20 in the chisel holder 46 of the chisel holder 40. For this purpose, the fastening sleeve 20 has holding elements 21 which engage in a circumferential groove 15 of the chisel shank 11. Furthermore, the fastening sleeve 20 has a clamping slot 23. This enables the fastening sleeve 20, which is made of resilient material, to be pressed against the wall of the chisel receptacle 46 on account of its inherent tension and thus to be fixed thereon. The chisel 10 is thus rotatable about its longitudinal axis, but held axially, fixed in the chisel receptacle 46. The axial mounting enables a defined axial play 50 of the chisel 10, indicated by a double arrow, in order to enable the chisel 10 to rotate easily.

A disc-shaped support element 30 is arranged between the chisel head 13 and the chisel holder 40, as is shown in more detail in FIG Figure 2 is shown, wherein the outer contour of the disk-shaped support element 30 follows a geometric shape and / or an arbitrary shape.

For operation, the chisel holder 40 with its plug-in attachment 42 is placed in a corresponding holder on a milling drum (not shown) of a milling machine assembled. The chisel 10 is fastened to the holding projection 43 of the chisel holder 40 by means of the fastening sleeve 20, together with the support element 30. During operation, the chisel 10 is guided through the clearing material by a rotary movement of the milling drum. The chisel 10 rotates automatically due to acting forces, so that uniform radial wear of the chisel 10 is achieved.

Figure 2 shows one in the Figure 1 II marked detail of the tool system with a chisel 10 and a support element 30 according to the prior art. The chisel head 13 is closed in the direction of the chisel shank 11 with a collar 13.2 which forms a contact surface 13.1. This lies on a support surface 32 of the support element 30. The support surface 32 is formed within a receptacle 31 on the top of the support element 30. Accordingly, it is limited on the outside by an edge 31.1. On the side opposite the support surface 32, the support element 30 has a seat surface 33, with which it rests on a wear surface 47 of the cylindrical section 44 of the holding projection 43. The support element 30 is constructed essentially rotationally symmetrically to a central longitudinal axis (M) of the chisel 10. The seat surface 33 merges via a circumferential recess 35 into a centering surface 34.1 of a centering projection 34, which is inclined to the central longitudinal axis M. How Figure 2 clearly illustrated, the centering projection 34 of the support element 30 is inserted into a correspondingly shaped centering receptacle 48 of the chisel holder 40.

Along the central longitudinal axis (M), the support element 30 has a receiving bore 39 through which a guide region 36 for guiding the chisel 10 is formed. In the assembly position, the centering section 12 of the chisel shank 11 is assigned to the guide area 36. In this way, a rotary bearing is created between the guide region 36 and the centering section 12. It should be ensured here that the outer diameter of the cylindrical centering section 12 is matched to the inner diameter D _{i of} the receiving bore 39 in the guide region 36 in such a way that free rotation between the support element 30 and the centering section 12 is maintained. The game between these two Components should be selected so that there is as little lateral offset as possible (transverse to the central longitudinal axis of the chisel (10)). As already mentioned Figure 1 shown, the centering section 12 merges into a cylindrical chisel shaft 11 after a tapering region 12.1.

The chisel shaft 11 is held in the holding projection 43 of the chisel holder 40 by means of the fastening sleeve 20. The fastening sleeve 20 has a chamfer 22 at its upper end.

During operation, the chisel 10 can rotate about the central longitudinal axis. The free rotatability ensures that the chisel 10 wears evenly over its entire circumference. The loosely placed support element 30, which is held by the centering section 12 of the chisel shaft 12, also rotates, as a result of which the overall rotatability of the chisel 10 is further improved. The rotation and the high mechanical load on the chisel 10 also result in wear on the chisel holder 40, mainly in the upper section 44 of the holding projection 43. The wear surface 47 is rubbed off by the load. The existing wear of the retaining lug 43 can be done in Figure 1 shown wear marks 45 are evaluated.

Due to the relative movement between the support element 30 and the holding projection 43, the wear surface 47 of the holding projection 43, which is flat in the new state, grinds into the recess 35 of the supporting element 30, as shown in FIG Figure 2 is shown. A support 47 30 is provided with an additional lateral guidance through a projection 47. 1 that is formed in accordance with the contour of the recess 35, which has a positive effect on the rotatability of the support element 30 and thus of the chisel 10. The centering surface 34.1 merges tangentially into the surface of the recess 35, so that no edges which hinder the rotatability are formed. Correspondingly, the surface of the recess 35 merges into the seat 33 via a rounding section without sharp edges. With its radially outer surface section, the recess 35 counteracts forces which act radially inward on the support element 30. The radially inner surface section counteracts radially outward forces.

This reduces the force which has to be absorbed by the centering surface 34.1, which in this area leads to a reduced surface pressure and correspondingly to a reduced wear. In addition, this support also counteracts a wobble movement in the disk plane of the support element 30, which reduces wear on the chisel holder 40. Furthermore, the recess with its counterpart ground from the wear surface 47 serves as a labyrinth-like seal. Debris that gets between the seat surface 33 and the wear surface 47 is prevented from advancing by this seal and thus only reaches the area of the chisel shaft 11 to a reduced extent.

Figure 3 shows a schematic representation of the wear of the wear surface 47 of the chisel holder 40 in the case of a known support element 30 and in the case of an asymmetrical loading of the support element 30. In the embodiment shown, the disk-shaped support element 30 is provided by a flat support surface 32 and an opposite, also flat seat surface 33 limited. The centering projection 34 is formed with its centering surface 34.1 all around the central receiving bore 39 on the seat surface 33. The receiving bore 39 has an inner diameter D _i 58. On the side of the support surface 32, the receiving bore 39 has an insertion phase 36.1.

The asymmetrical load is represented by two arrows of different lengths, which symbolize a first force 55.1 and a larger second force 55.2. The asymmetrical introduction of force can be caused, for example, by the position of the bit holder 40 in relation to the direction of rotation of the milling drum. Such a non-uniform axial load leads to an asymmetrical wear on the wear surface 47 of the bit holder 40 with a larger lateral movement (radial movement 54) of the support element 30. This is due to a wear angle 56 course of the wear surface which is inclined relative to a plane perpendicular to the central longitudinal axis M. 47 indicated. The radial movement 54 is made possible with insufficient lateral guidance of the support element 30. As a result of such asymmetrical wear of the wear surface 47, the support element guiding the chisel 10 lies 30 at an angle to the central longitudinal axis M on the wear surface 47. So that the receiving bore 39 is not exactly aligned with the central longitudinal axis M of the chisel holder 46. Due to this incorrect position, the smooth rotation of the chisel 10 can be hindered or prevented.

Figure 4 shows a side sectional view of a section of a support element 30 according to the invention in a first embodiment.

The support surface 32 is arranged in the receptacle 31 for mounting the chisel head 13. A groove-shaped recess 35 is formed in the support surface 32 in the opposite seat surface 33 in the transition to the centering surface 34.1 of the centering projection 34. The recess 35 has a first radius 35.1 in a range between 0.5 mm and 6 mm, in the present case 1.5 mm. The depth of the recess 35 relative to the seat 33 is preferably in a range between 0.3 mm and 2 mm, preferably between 0.5 mm and 1.5 mm, in the present case 1.0 mm. The recess 35 merges into the seat 33 over a rounded region with a second radius 35.2. The transition from the recess 35 to the centering surface 34.1 runs in a straight line. Edges between the centering surface 34.1, the recess 35 and the seat surface 33 are thus avoided, which improves the free rotatability of the assembled support element 30 about the central longitudinal axis M.

An apex 35.5 forms an inner end 53 of the recess 35. The centering projection 34, facing away from the seat 33, is closed off by a web-shaped end 34.2. A collar height 52 is represented by a double arrow. The collar height 52 in the present exemplary embodiment represents the distance, measured in the direction of the central longitudinal axis M, between the end 34.2 of the centering projection 34 and the end 53 of the recess 35.

In the exemplary embodiment shown, the recess 35 is formed in the seat 33 of the support element 30. Mounted, the support element 30 lies with its seat 33 on the in Figure 2 shown wear surface 47 of the chisel holder 40. Is the wear surface 47 flat until it transitions into the centering receptacle executed, the shoulder 47.1 grinds into the recess 35 during the use of the tool system and the support element 30 rotating about the central longitudinal axis M. As an alternative to this, it can also be provided that the projection 47.1 corresponding to the recess 35 is already molded onto the wear surface 47 during the manufacture of the bit holder 40. The approach 47.1 can already have its final contour adapted to the recess 35. It is also possible that the projection 47.1 is only approximately adapted to the contour of the recess 35 during the manufacture of the chisel holder 40. The final contour of the shoulder 47.1 then results during the use of the tool system, in which the shoulder 47.1 grinds into the recess 35. According to a further possible embodiment, the seat surface 33 can be designed without a recess 35 formed therein. Instead, the shoulder 47.1 is molded onto the wear surface 47 of the bit holder 40. During operation, the shoulder 47.1 now grinds into the wear surface 33 of the support element 30 and thus forms the recess 35.

An outer diameter 51 of the support element 30 and the inner diameter 58 of the receiving bore 39 of the support element 30 are each marked by an arrow. In the exemplary embodiment shown, the outer diameter 51 corresponds to an outer diameter 57 of the seat 33.

According to the invention, the collar height 52 is designed such that the ratio between the inside diameter 58 of the receiving bore 39 of the support element 30 and the collar height 52 assumes a value less than 8. The collar height 52 is predetermined by the axial dimensioning of the centering projection 34 and the recess 35.

With a ratio of less than 8 between the inner diameter 58 of the receiving bore 39 of the support element 30 and the collar height 52, good lateral guidance of the support element 30 and thus of the chisel 10 is ensured. In particular, the collar height 52 is designed such that it is greater than the axial play 50 of the chisel 10 and thus of the support element 30 Dimensioning of the collar height 52 as a function of the inner diameter 58 of the receiving bore 39 of the support element 30 takes into account the larger permissible axial play 52 in the case of larger tool systems. A sufficient lateral guidance of the support element 30 and thus of the chisel 10 is thus always guaranteed, regardless of the tool size.

Due to the centering surface 34. 1 resting against the centering receptacle 48, a good radial guidance of the support element 30 is achieved even with maximum deflection of the chisel 10 from the chisel holder 46 within the permissible axial play 50. A further lateral guidance of the support element 30 is achieved through the recess 35 and the shoulder 47. 1 of the chisel holder 40 engaging therein. Lateral movements or wobbling movements of the support element 30 can thus be reliably avoided. As a result, the wear of the support element 30 and the bit holder 40 can be significantly reduced. An asymmetrical wear of the wear surface 47 in the event of an uneven load on the support element 30, as is the case with Figure 2 described can be avoided or at least significantly minimized. Due to the lack of angular misalignment of the wear surface 47 as the contact surface of the support element 30 and thus of the chisel 10 with respect to the central longitudinal axis M, a consistently good rotation of the chisel 10 and the support element 30 is achieved. Exact lateral guidance of the chisel 10 also takes place by its centering section 12 of the chisel shank 11 being in contact with the guide region 36 of the support element 30. By the exact lateral guidance of the support element 30 and thus the chisel 10 and the reduced wear of the support element 30 and the chisel holder 40 the rotational movement of both the support element 30 and the chisel 10 is stabilized. As a result, the wear of the chisel 10 and the chisel head 13 in particular can be reduced.

Furthermore, with a ratio of less than 8 between the inside diameter 58 of the receiving bore 39 of the support element 30 and the collar height 52, an improved sealing effect against penetrating foreign substances is achieved by the interlocking contours of the support element 30 and the upper side of the holding projection 43 of the bit holder 40 than in tool systems with one Ratio greater than or equal to 8. For example, less debris penetrates into the area of the bit holder 46, which reduces wear in this area and ensures that the bit 10 can be rotated.

The easy rotatability of the support element 30 and the chisel 10 is further maintained by the rounded or rectilinear and thus edge-free transitions between the centering surface 34.1, the receptacle 35 and the seat surface 33. Sharp transitions easily cause the support element 30 to tilt relative to the bit holder 40 and prevent rotation. This can be avoided by the rounded or straight transitions.

The Figures 5 to 14 each show a section of a support element 30 in further embodiments in schematic sectional side views.

In the in the Figures 5 to 11 and the exemplary embodiments shown in FIGS. 13 and 14, the support elements 30 have a flat support surface 32. As an alternative to this, however, it is possible in each case to correspond to the embodiment Figure 4 to provide a receptacle 31 bordered by an edge 31.1 on the upper side of the support element 30. The receptacle 31 then forms the support surface 32, on which the chisel head 13 rests with its support surface 13.1. An insertion chamfer 36.1 is arranged at the transition from the support surface 32 into the guide area 36. Alternatively, the transition can also be rounded.

In the embodiments according to the Figures 5 to 12 corresponds to the outer diameter 51 of the support element 30 to the outer diameter 57 of the respective seat 33. In the exemplary embodiments corresponding to FIGS Figures 13 and 14 a bevel 38 is arranged all around the seat 33. In these exemplary embodiments, the outer diameter 51 of the support element 30 is correspondingly larger than the outer diameter 57 of the associated seat 33.

At the in Figure 5 In the exemplary embodiment of a support element 30 shown, a guide web 37 is arranged on the seat surface 33. The guide web 37 runs spaced from the centering projection 34. It has a trapezoidal contour with side surfaces extending at an angle to the seat surface 33. The guide webs 37 are closed off from the chisel holder 40 by a seat surface section 33.1. The recess 35 is formed between the centering shoulder 34 and the guide web 37. It also has a trapezoidal contour. The end 53 of the recess 35 is formed by a contact surface 35.3. In the exemplary embodiment shown, the contact surface 35.3 lies in the same plane as the seat 33 on the side of the guide web 37. Towards the central longitudinal axis M, the contact surface 35.3 merges into the inclined centering surface 34.1 of the centering projection 34. The centering extension 34 is closed off by its web-shaped end 34.2 towards the bit holder 40.

The collar height 52 is measured in the direction of the central longitudinal axis between the end 34.2 of the centering projection 34 and the end 53 of the recess 35, as is shown by a double arrow. The ratio between the inner diameter 58 of the receiving bore 39 of the support element 30 and the collar height 52 is chosen to be less than 8, in the present case less than 6.5. As a result, good lateral guidance of the support element 30 and a good sealing effect against penetrating foreign substances are achieved with the advantages described. With a ratio of less than 6.5, sufficient lateral guidance is also achieved towards the end of the service life of the support element 30 and the chisel 10, if the axial play 50 of the chisel 10 is possibly increased due to the wear that has already occurred.

It is conceivable to form the collar height 52 on the centering projection 34 with a longitudinal extension, which leads to a ratio between the inside diameter 58 of the receiving bore 39 of the support element 30 and the collar height 52 that is greater than 8. In this way, an improved support of the centering surface 34.1 on the inner surface of the bit holder 46 and / or an improved support of the outer surface of the collar height 52 with the outer surface of the free area of the bit shaft can be achieved.

Mounted, the guide web 37 rests on the wear surface 47 of the bit holder 40. As a result of the rotation of the support element 30, it grinds into the wear surface 47 and thus forms a corresponding web receptacle in the end surface of the chisel holder 40. As a result, both the lateral guidance of the support element 30 and the sealing effect are significantly improved.

In a departure from the embodiment shown, the transition from the centering surface 34.1 to the contact surface 35.3 and / or the transition from the contact surface 35.3 to the adjacent side surface of the guide web 37 and / or the transition from the opposite side surface of the guide web 37 to the adjacent seat surface 33 can be rounded off his. The transitions from the side surfaces to the seat surface section 33.1 can also be rounded. This way, sharp edges can be avoided. This leads to an improved rotatability of the support element 30.

At the in Figure 6 Support element 30 shown is also a trapezoidal guide web 37 is arranged on the side of the support element 30 facing the bit holder 40. A recess 35 formed between the guide web 37 and the centering projection 34 has a throat-shaped contour. The radius of the recess 35 is selected such that its surface merges tangentially into the centering surface 34.1 and the adjacent side surface of the guide web 37. The collar height 52 corresponds to the distance running in the direction of the central longitudinal axis M between the end 34.2 of the centering projection 34 and the apex 35.5 of the throat-shaped recess 35. The immediately successive combination of the centering projection 34, the recess 35 and the guide web 37 in conjunction with a correspondingly shaped wear surface 47 of a chisel holder 40 achieves a good sealing effect against penetrating material.

The seat 33 of the in Figure 7 Support element 30 shown merges directly into the centering surface 34.1 of the centering projection 34. In the outer area of the seat 33, a groove-shaped recess 35 is let into the seat 33. The collar height 52 is along the central longitudinal axis M between the end 34.2 of the Centering approach 34 and the apex 35.5 of the groove-shaped recess 35 measured. The recess 35 arranged comparatively far outside on the support element 30 results in particularly good stabilization of the rotational movement of the support element 30.

In Figure 8 A support element 30 with a multi-stage recess 35 and a guide web 37 is shown. The centering surface 34.1 runs into the recess 35 and merges there into a contact surface 35.3 arranged transversely to the central longitudinal axis M, in particular perpendicularly to the central longitudinal axis M. A groove-shaped area 35.4 adjoins the contact surface 35.3 as a further deepening of the recess 35. The surface of the groove-shaped region 35.4 merges tangentially into the adjacent side surface of the guide web 37. The trapezoidal shaped guide web 37 forms a seat surface section 33.1, which is connected to the further seat surface 33 via the outer side surface of the guide web 37. The contact surface 35.3, the seat surface section 33.1 and the outer seat surface 33 run transversely, in particular perpendicularly to the central longitudinal axis M. The contact surface 35.3 is molded further into the support element 30 than the seat surface 33. The collar height 52 is between the end 34.2 of the centering projection 34 and the The apex 35.5 is measured as the end 53 of the groove-shaped region 35.4 of the recess 35.

The different planes in which the support surface 33, the support surface section 33.1 and the contact surface 35.3 are arranged lead both to a good lateral guidance of the support element 30 and to a good sealing effect.

At the in Figure 9 The embodiment of the support element 30 shown is formed with concentrically arranged recesses 35 around the centering projection 34 in the support element 30. A wavy contour is thus formed, the surface of which represents the seat surface 33. Deviating from this, it can also be provided that the recesses 35 are formed by a groove which spirally surrounds the centering projection 34. The collar height 52 is measured between the end 34.2 of the centering projection 34 and the apex 35.5 of the innermost recess 35. With adjacent recesses 35 of different depths Collar height 52 preferably determined at the end 53 of the deepest recess 35. A good rotatability of the support element 30 is ensured by the recesses 35 arranged all around the centering projection 34. Furthermore, the engagement of corresponding lugs 47.1 of the bit holder 40 leads to a good sealing effect. Due to the wavy contour, the surface projected in the axial direction remains the same as a flat surface, so that the axial support effect is retained. The radially effective area is significantly increased by the side flanks of the recesses 35. This makes it easier to absorb lateral forces. The contact surface between the support element 30 and the one in FIG Figure 1 Chisel holder 40 shown enlarged. This reduces the surface pressure between the support element 30 and the bit holder 40, which leads to reduced wear and improved rotatability.

Figure 10 shows a support element with a flat seat 33, in which two concentrically extending, groove-shaped recesses 35 are incorporated. This arrangement also achieves good rotatability, good lateral stabilization and a good sealing effect against penetrating debris.

This in Figure 11 The support element 30 shown has a rectilinear seat surface 33 which is oriented obliquely to the central longitudinal axis M. The maximum recess in the support element 30 is formed in the rounded transition area from the centering surface 34.1 into the wear surface 33. Both the centering surface 34.1 and the wear surface 33 have a radial stabilizing effect on the position of the support element 30 due to their orientation obliquely to the central longitudinal axis M. The collar height 52 is from the end 34.2 of the centering projection 34 to the end 53 in the transition region from the centering surface 34.1 to the wear surface 33 measured.

At the in Figure 12 Support element 30 shown, both the support surface 32 and the seat surface 33 extend obliquely to the central longitudinal axis M. The support surface 32 and the seat surface 33 are preferably arranged plane-parallel to one another. The largest distance between the end measured in the direction of the central longitudinal axis M. 34.2 of the centering section 34 and the seat 33 results in relation to the outer edge of the support element 30, so that this distance forms the collar height 52. In this exemplary embodiment, too, both the centering surface 34.1 and the seat surface 33, which is oriented obliquely to the central longitudinal axis M, have a radially stabilizing effect on the support element 30.

Figure 13 shows a support element 30 with an outer bend 38. The centering surface 34.1 of the centering projection 34 merges into the support surface 33 which runs flat. The support surface 33 is preferably oriented perpendicular to the central longitudinal axis M. The outer diameter 57 of the seat surface 33 is selected to be slightly larger than the diameter of the wear surface 47 of the bit holder 40. The bevel 38, which is of rectangular design in the exemplary embodiment shown, extends in the direction of the chisel holder 40. When mounted, it engages around the upper section 44 of the holding projection 43 and thus leads to an additional lateral stabilization of the support element 30. Furthermore, the bevel 38 protects the area between the chisel holder 40 and the support member 30 from penetrating material. In order to avoid jamming of the support element 30, the transitions from the centering surface 34.1 into the seat surface 33 or from the seat surface 33 to the fold 38 can be rounded. The collar height 52 is marked by a double arrow as the distance between the end 34.2 of the centering section 34 and the seat 33.

Also Figure 14 shows a support element 30 with a bevel 38 encompassing the holding projection 43 of the chisel holder 40. The seating surface 33 is in this case arched inward. This makes one compared to the one in Figure 13 Embodiment shown improved lateral guidance and improved rotatability about the central longitudinal axis M of the support member 30 achieved. The distance between the end 34.2 of the centering projection 34 and the inner end 53 of the seat 33 corresponds to the collar height 52.

In all of the exemplary embodiments shown according to the invention, the respective collar height 52 is designed to be greater than the permissible axial play 50 of the chisel 10 and thus of the support element 30. This means that even at a maximum Deflection of the chisel 10 from the chisel holder 46 achieves sufficient lateral guidance of the support element 30. Due to the different possible contours of the side of the support element 30 facing the chisel holder 40 and the correspondingly designed upper side of the chisel holder 40, the lateral guidance and the sealing against penetrating foreign bodies can be adapted to the corresponding requirements. What is essential here is the ratio of less than 8 between the inside diameter 58 of the receiving bore 39 of the support element 30 in relation to the respective collar height 52, since from this ratio the radial movement of the support element 30 is blocked in such a way that increased wear, as caused by radial movements of the Support element 30 is caused is excluded.

Tests by the applicant have shown that, for example, the formation of a centering projection 34, a guide web 37 and / or a recess 35 with an interrupted contour profile, for example as a web-like contour profile or a plurality of individual recesses 35 distributed over the contour profile, the grinding behavior of a rotating chisel on the end face of the ownership positively favored. As a result, it can be determined that the ground-in centering projection 34 forms a so-called labyrinth seal on the end face of the holder shaft, in order to protect the inner bore 39 against undesired contamination or contamination from the cavity that forms between a centering projection 34, a guide web 37 and / or to be able to specifically derive a recess 35 and the end face of a holder shaft due to an axial displacement of the chisel. Such interruptions can additionally be formed in a radial longitudinal extension of different lengths in order to further improve the discharge of contaminants.

Furthermore, the derivation of the pressure occurring in the holder due to the rotary movement of the chisel can be improved.

Claims (15)

Chisel (10), in particular round shank chisel, with a chisel head (13) and a chisel shank (11), with a support element (30) which has a seat surface (33) on its underside and a centering projection (34) projecting beyond the seat surface (33) , wherein the centering projection (34) has a centering surface (34.1) which is inclined to the central longitudinal axis (M) of the chisel (10) and which merges directly or indirectly into the seat surface (33) and wherein the support element (30) along the central longitudinal axis (M) is pierced by a receiving bore (39) with an inner diameter Di (58) for receiving the chisel shank (11),
characterized,
that in the direction of the central longitudinal axis (M) between an end (34.2) of the centering projection (34) facing away from the seat surface (33) and the seating surface (33) or between the end (34.2) of the centering projection (34) and an inner end (53 ) of a collar height (52) measured in relation to the seat surface (33) and recessed into the support element (30) is designed such that the collar height (52) is greater than an axial play (50) of the in a chisel holder (40) mounted chisel (10). Chisel (10) according to claim 1,
characterized,
that the ratio between the inside diameter Di (58) of the receiving bore (39) and the collar height (52) is less than 7.5, preferably less than 7.0, particularly preferably less than 6.5. Chisel (10) according to claim 1 or 2,
characterized,
that the centering projection (34) and / or the recess (35) are arranged circumferentially to the receiving bore (39). Chisel (10) according to one of claims 1 to 3,
characterized,
that several recesses (35) of the same or different depth or at least one recess (35) running spirally around the centering projection (34) are formed in the seat surface (33) and that the ratio between the inside diameter Di (58) of the receiving bore (39) of the Support element (30) and the collar height (52) to one of the recesses (35) or the grooves of the spiral recess (51), preferably the ratio between the inner diameter Di (58) of the receiving bore (39) and the largest to a recess (35 ) or a groove certain collar height (52), is less than 8. Chisel (10) according to one of claims 1 to 4,
characterized,
that a guide web (37) projects at a distance from the centering projection (34) beyond the adjacent seat surface (33). Chisel (10) according to claim 5,
characterized,
that the recess (35) is formed between the centering projection (34) and the guide web (37) and that the centering projection (34) has a greater height than the guide web (37) relative to the adjacent seat surface (33). Chisel (10) according to one of claims 1 to 6,
characterized in that transitions between the centering surface (34.1), the seat surface (33), the recess (35) and / or the guide web (37) are rectilinear or rounded. Chisel (10) according to one of claims 1 to 7,
characterized,
that the depth of the recess (35) relative to the seat surface (33) is greater than or equal to 0.3 mm, preferably between 0.3 mm and 2 mm, particularly preferably between 0.5 mm and 1.5 mm. Chisel (10) according to one of claims 1 to 8,
characterized in that the support element (30) has a receiving bore (39) with an inner diameter Di (58) of 20 mm and the collar height (52) is greater than 2.5 mm and / or that the supporting element (30) has a receiving bore ( 39) with an inner diameter Di (58) of 22 mm and the collar height (52) is greater than 2.75 mm and / or that the support element (30) has a receiving bore (39) with an inner diameter Di (58) of 25 mm and the collar height (52) is greater than 3.125 mm and / or that the support element (30) has a receiving bore (39) with an inside diameter Di (58) of 42 mm and the collar height (52) is greater than 5.25 mm , Chisel according to one of claims 1 to 9,
characterized,
that the ratio between the inner diameter Di (58) of the receiving bore (39) of the support element (30) and the collar height (52) is less than 8. Tool system with a chisel (10), in particular a round shank chisel, which has a chisel head (13) and a chisel shank (11), with a support element (30) which has a seat surface (33) on its underside and one which projects beyond the seat surface (33) Centering projection (34), wherein the centering projection (34) has a centering surface (34.1) which is inclined to the central longitudinal axis (M) of the chisel (10) and which merges directly or indirectly into the seat surface (33), the support element (30) along the The central longitudinal axis (M) is broken through by a receiving bore (39) with an inner diameter Di (58) for receiving the chisel shaft (11), with a chisel holder (40) for receiving the chisel shaft (11), the chisel holder (40) supporting the 30) facing a wear surface (47) for supporting the seat surface (33) and a centering seat (28) for receiving the centering shoulder (34) of the support element (30),
characterized in that in the direction of the central longitudinal axis (M) between one end of the centering receptacle (48) facing away from the wear surface (47) and the wear surface (47) or between the end of the centering receptacle (48) and a maximum point of one over the wear surface (47 ) protruding approach (47.1) measured centering height is designed such that the collar height (52) is greater than an axial play (50) of the chisel (10) mounted in a chisel holder (40). Tool system according to claim 11,
characterized in that the support element (30) rests with its seat surface (33) on the wear surface (47) of the chisel holder (40) and that at least one shoulder (47.1) of the chisel holder (40) protruding beyond the wear surface (47) corresponds to one recess (35) of the support element (30) is formed in the seat surface (33) and projects into it. Tool system according to claim 12,
characterized,
that the support element (30) has a guide web (37) which projects beyond the adjacent seat surface (33) and that the bit holder (40) has a web receptacle molded into the wear surface (47) and corresponding to the guide web (37), into which the guide web (37) protrudes. Tool system according to one of claims 11 to 13,
characterized in that the shoulder (47.1) and / or the web receptacle are attached to the wear surface (47) by a shaping process in the manufacture of the chisel holder (40) and in that the corresponding recess (35) and / or the corresponding guide web (37 ) are formed during operation of the tool system by abrasion of the seat surface (33) and / or that the recess (35) and / or the guide web (37) is formed on the seat surface (33) by a shaping process in the production of the support element (30) are attached and that the Corresponding approach (47.1) and / or the corresponding web holder during operation of the tool system are formed by abrasion of the wear surface (47). Tool system according to one of claims 11 to 14,
characterized,
that the ratio between the inner diameter Di (58) of the receiving bore (39) of the support element (30) and the centering height is less than 8.

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