WO2014000935A2 - Bit carrier for a drill head - Google Patents

Description

 Chisel carrier for a drill head

The invention relates to a bit carrier for a drill head with a tool head (26) receiving a drill bit and having a mounting portion for interchangeable coupling of the bit carrier, or wherein the bit carrier is connected to the mounting portion with a tool holder,

Drilling heads are used to excavate holes in the ground during construction work. The drill heads are attached to the end of a drill pipe. About the drill string, the rotation and the feed of a drive unit can be transferred into the drill head.

Horizontaibohrgeräte are known from the prior art, for example, in which a more horizontal hole is introduced into the soil. In this case, the drill head is driven through, for example, under roads, buildings or the like. The drill heads usually have a tool holder holding drill bits mounted on lugs. When the drill head is driven through the soil If so, the drill bits roll on the material to be removed and trigger it. It is finely divided so that it can be washed out with a rinsing emulsion. The flushing operation is supplied to the drill heads via the drill string. The drill heads are subject to heavy wear and must therefore be replaced regularly.

It is an object of the invention to provide a bit carrier of the type mentioned, which is designed wear-optimized.

This object is achieved in that the attachment portion of the bit carrier in the forward feed direction has a discharge surface, which merges into a radially outer side surface. During the drilling process, the side surface of the inner wall of the bore is assigned. Thus occurs here a relatively high wear, which is strongest in the feed direction on the front side surface. With the invention of this area subjected to severe wear is now assigned to the discharge surfaces and the side surfaces and thus the bit carrier. Thus, it is primarily the bit holder and less the tool holder on which the bit carriers are mounted that wears. The tool holder is thus protected against the highly abrasive wear in the borehole area. Thus, the tool holder can be used with a long service life.

According to a preferred variant of the invention, a particularly wear-resistant design of the bit carrier has resulted from the fact that the discharge surface extends to the connection region of the drill bit. Thus, the no space material can accumulate in the transition region of the bit carrier to the drill bit. It has been shown that such material collections, which are partially compressed by the high drilling pressures partially, lead to high friction wear on the rotating drill bit. A particularly good dissipative effect is achieved in that the discharge surface runs inclined at least in regions counter to the feed direction.

A compact design can be achieved for the bit carrier, for example, by the fact that the Ableitfiäche is part of a plug-in approach, which has a mounting receptacle for interchangeable Ankoppiung to a tool holder.

A particularly preferred variant of the invention is the shape that in the transition region between the Ableitfläche and the side surface a reaming edge is formed. It has been shown that a particularly good dissipative effect is created by the angled adjustment of the side surface to the discharge surface. In addition, the reaming edge of a secondary cutting edge can be used to produce high-quality borehole contours. Among other things, this leads to a high level of smoothness of the drill head.

An embodiment of the invention is such that the fastening receptacle with which the bit carrier can be mounted on a tool holder is recessed into the insertion projection. Thus, the mounting surfaces that secure the bit carrier relative to the tool holder, housed in protected material area of the bit carrier and therefore wear-resistant.

A further wear optimization of the bit carrier can be achieved in that the side surface of the deflection surface facing away and opposite to the feed direction in an open space, which is oriented opposite to the feed direction.

It has proved to be particularly advantageous that the fastening receptacle is arranged in the region between the discharge surface and the free surface. A stable construction of the bit carrier results for example from the fact that the discharge surface and / or the free surface is arranged on a guide piece, and that the guide piece has a guide of the fastening receptacle.

In the case of a bit carrier according to the invention, provision may also be made for the fastening receptacle to have on opposite sides linear guides, in particular prism guides. About the linear guides, in particular the prism guides, a dimensionally accurate assignment of the Werkzugträgers can be achieved to a tool holder. In addition, a large support distance for removal of high moments can be achieved by the spacing of the linear guides.

In a bit holder according to the invention, the insertion projection can be designed such that the reaming edge is arranged to form a free-cutting region on a different pitch circle than the region of the side face that directly or indirectly adjoins the reaming edge. In this way, a drainage of the space material is favored, so that the risk of severe frictional wear is minimized.

If it is provided that the front area in the feed direction of the carrier area in the feed direction in the radial direction has a greater structural height, and / or forms a larger Verschleißvoiumen, then the bit carrier is designed material optimized. It therefore has a greater wear capacity in the area subject to increased wear.

A bit holder according to the invention can also be such that the side face in the connection area to the drill bit has a wear protection layer and / or that the drill bit has a wear protection layer in the connection area to the side face, the wear protection layer being characterized by a hard surface. is formed. This wear protection layer protects the area particularly susceptible to risk of breakage in favor of an increased service life of the bit carrier.

A particularly preferred variant of the invention is such that the fastening receptacle is opened radially inwardly. In this way, space material that has possibly penetrated into the region of the fastening receptacle can be easily washed out, so that no jamming of the bit carrier occurs during assembly or disassembly.

The invention will be explained in more detail below with reference to an embodiment shown in the drawings. Show it:

1 is a perspective side view of a drill head with a

 Tool holders and chisel carriers mounted thereon with drill bits.

2 shows the drill head according to FIG. 1 in a side view and in partial section, FIG.

3 a chisel carrier in a perspective front view,

Fig. 4 is a in Fig. 2 with IV-IV marked section detail and

Fig. 5 the bit carrier according to FIG. 3 in full section.

Fig. 1 shows a drill head with a tool holder 10, which has a support body 12 as the base part. On the support body 12, a downwardly projecting mounting lug 11 is integrally formed. In this case, the attachment lug 11 has a conical external thread. The support body 2 is provided with three tool holders. equipped men 13, which are mutually offset by 120 ° on the outside of the support body 12 are arranged.

4 shows the design of the tool holder 13 more clearly. As this drawing shows, stands on the support body 12 on the outside per tool holder 13 before a guide projection 13.1. Each guide lug 13.1 has on opposite sides longitudinal guides in the form of prismatic guides. In this case, the two prism guides are formed by two guide surfaces 22 which are set at an angle to each other. An angle in the range between 45 ° and 75 ° between the guide surfaces 22.1 has proved particularly suitable. In this case, a simple assembly in rough construction site operation can be guaranteed. In addition, this embodiment of the guide lugs 13.1 is not prone to jamming. The Führungsfiächen 22.1 extend in the longitudinal direction of the guide, as shown in FIG. 3 and FIG. 5 can be seen. At the tool holders 13, the tool holder 10 can be attached.

As FIGS. 3 and 5 show, the bit carriers 20 have a tool head 26, to which an insertion projection 21 is connected in one piece. The plug 21 forms radially inwardly lying a recessed mounting receptacle. In this case, the fastening receptacle is open radially inwards and in the downward direction, as shown in FIG. 3 reveals. The attachment receptacle is bounded by prism-shaped mutually engaged flanks 13.3. The flanks are 13.3 at the same angle as the guide surfaces 22.1 set to each other, so that with the flanks 13.3 and the Führungsfiächen 22.1. Forming guided tours.

As can be seen in FIG. 4, the flanks 13.3 are part of guide pieces 22 which delimit the fastening receptacle 21 .1 in the feed direction V in front and in the rear in the opposite direction to the feed direction V. The guide pieces 22 each form a projection 22.2, which carries one of the flanks 13.3 and the guide projection 13.1 engages positively behind. For an offset of the bit carrier 20 in the radial direction is no longer possible. The bit carrier 20 can only be moved in the guide direction. The two guide pieces 22 are connected to each other by means of a wall portion 21.2, in connection area to the tool holder 12 close the guide pieces 22 with inner surfaces 24 which are aligned with each other and arranged on one level. The outside of the bit carrier 20 is bounded by a side surface 25. This side surface 25 is divided into several partial surfaces. In the feed direction in front, the side surface 25 has a first surface portion 25.1, which merges into a discharge surface 25.2 at an angle. The discharge surface 25.2 is opposite to the feed direction V inclined, as shown in FIGS. 3 and 4 can be seen. The Abieitfläche 25 passes over a reaming 25.6 in a radially outer side surface 25.3. The reaming edge 25.6 extends substantially in the direction of the central longitudinal axis of the bit carrier 20. Contrary to the feed direction V, the side surface 25.3 merges into an open surface 25.4 at the rear, wherein an edge region is likewise formed between the side surface 25.3 and the free surface 25.4. Finally, the free surface 25.4 ends with a surface section 25.5, which, like the surface section 25.1, merges into the inner surface 24.

As can be seen in FIG. 3 and also in FIG. 5, a fastening receptacle 21.3 in the form of a bore is arranged in the region of the insertion projection 21, which passes through the two guide pieces 22. To mount the bit carrier 20 on the tool holder 10, the bit carrier 20 is attached to the guide surfaces 22.1 in the region of its bottom open side with the flanks 13.3. Subsequently, the bit carrier 20 can be plugged with its insertion projection 21 in the guide longitudinal direction on the guide projection 13.1 of the tool holder 13. The Aufsteckbewegung is mitteis a stop 21.4 (see Fig. 5) limited. In this case, the stop 21.4 to form a positive connection is also formed by an inner prism. This works with corresponding Prismenfiächen the leadership approach 13.1 Leadership Approach 13.1 together. In the assembled state, the bore receptacle 21.3 is in alignment with a corresponding bore receptacle in the guide projection 13.1. Then a corresponding fastening element, for example a clamping sleeve, can be pushed through the aligned bore receptacles 21.3 of the plug-in projection 21 and of the guide projection 13.1. Thus, the offset of the bit carrier 20 relative to the tool holder 10 is blocked in the guide direction.

As can be seen in FIG. 4, the front guide piece 22 in the feed direction V has a larger wear volume than the rear guide piece 22. FIG. 4 further shows that the assembly height of the front guide piece 22 in the radial direction is greater than the assembly height of the rear guide piece 22 (distance dimension d ₂ > dt). Thus, the reaming edge 25.6 is arranged on another, namely larger, pitch circle {circle center on the rotation axis R), as the edge region between the free surface 25.4 and the side surface 25.3. Thus, for the side surface 25.3 an opposite to the feed direction V radially inwardly sloping wear-optimized geometry, as shown in FIG. 4 clearly shows.

The plug 21 carries a tool head 26, to which a bearing portion 26.3 is integrally formed. In the transition region to the bearing section 26.3, the tool head 26 carries an annular circumferential projection 26.1 and subsequently a circumferential concentric groove 26.2. The approach 26.1 and the groove 26.2 form labyrinth seal. Following the cylindrical bearing section 26.3, a concave transition 26.4 is initially created in order to achieve an adaptation to an end-side, reduced-diameter nozzle piece. In this nozzle piece a circumferential groove 26.5 is incorporated. The bearing section 26.3 is closed at the end with an end face 26.7. As shown in FIG. 5, it is possible to esthetically incorporate into this end face 26.7 a recess into which a support element 26.6, consisting of a hard material, such as carbide, soldered, glued or pressed.

5 further reveals that an annular clamping element 29.1 in the form of a round wire snap ring is snapped into the circumferential groove 26.5.

FIGS. 2 and 5 show that a drill bit 30 can be rotatably connected to the bit carrier 20. The drill bit 30 has an outer surface 31 with at least one peripheral groove 32, 33. In bores of the side surface 31, hard material elements (34), in particular hard metal elements, can be soldered. The drill bit 30 has an inner bearing receptacle 37. This bearing holder 37 is incorporated in the form of a hole in the drill bit 30. The bearing receptacle 37 is reduced in diameter into a blind hole, which is equipped with a groove 38. The blind hole is completed with an end face into which a receptacle for a support member 39 is introduced. The support member 39 may be made of a hard material, such as hard metals. Anschiussbereich to the bearing holder 37 of the drill bit 30 is equipped with a circumferential groove 35 and then with a peripheral projection 36. The groove 35 and the boss 36 are labyrinth seal parts.

For mounting the tool 30 on the bit carrier 20, a bearing 29 is inserted into the bearing receptacle 37 of the drill bit 30 or mounted on the bearing portion 26.3 of the bit carrier 20. The bearing 29 is presently designed as a needle bearing, so that a low height can be realized.

As can be clearly seen in FIG. 5, a radial shaft sealing ring or a similar circumferential seal 28 is also introduced in the region between the bearing receptacle 37 and the bearing section 26.3. In the assembled state of the circumferential projection 36 of the drill bit 30 engages in the circumferential groove 26.2 of the tool holder 20th one. Similarly, the circumferential projection 26.1 of the Meißeiträgers 20 engages in the circumferential groove 35 of the drill bit 30, so that here a labyrinth seal is formed. Thus, therefore, the circumferential projections 36, 26.1 and the grooves 26.1, 25 formed sealing or labyrinth profiles, in connection with the labyrinth seal seals the seal 28 from the bearing receptacle 37, so that the bearing 29 by means of the labyrinth seal and the seal 28 is effectively protected from penetrating rock material and rinse emulsion. This ensures that the bearing 29 does not fail prematurely. For fixation of the drill bit 30 on the bit carrier 20, the clamping element 29.1 simultaneously engages in the two grooves 26.5 and 38. As a result, the drill bit 30 is held captive in the direction of the axis of rotation, but freely rotatable in the circumferential direction. The drill bit is supported with its support element 39 on the support element 26.6 of the mast guide 20 to form a pivot bearing that absorbs the axial forces. During assembly of the drill bit 30, the clamping element 29.1 slides on the between the bearing holder 37 and the groove 38 receiving bore area. As a result, the clamping element 29.1 is compressed radially inwardly into the groove 26.2 and reduces its diameter. The clamping element 29.1 can then snap into the groove 26.2, so that a positive connection is achieved.

After all three bit carrier 20 are fixed with their drill bits 30 to the tool holder 10, the drill head is ready for use. During the tool engagement, the tool holder 10 rotates and with it the bit carrier 20 about the rotation axis R. The drill bits 30 come into engagement with the material to be removed. As a result of the rotational movement, the drill bits roll in the borehole and the hard material elements 34 divide the material to be removed. About the flushing channel 15, an emulsion is fed, which is sprayed in the region of the nozzle 15.1. The emulsion flours the removed and crushed Good, the emulsion then flows through the discharge channels 14.1. As can be seen from FIG. 1, the discharge channels 14. 1 are in each case formed by an open surface 25. 4 and a discharge surface 25. 2 adjacent to each other. Limb carrier 20 and a surface portion of the support body 12 limited. 1 clearly shows that the discharge surface 25.2 extends as far as the attachment area to the drill bit 30. In this way, it is ensured that outflowing waste material does not accumulate in this area but can flow away, so that a material accumulation which is harmful to wear is prevented. 1 further reveals that the drill bit in the connection region is protected against the bit carrier 20 by means of an annular circumferential wear protection layer 30.1. As FIG. 2 further shows, in the drill bit 30 a circumferential groove is screwed in, which is filled with a weld which forms the wear-resistant layer 30.1. Likewise, the bit carrier in the connection region to the drill bit 30 is protected by means of a wear protection layer 25.7. This is also applied in the form of a hedge on the side surface 25.3, as shown in FIGS. 1 and 5 show.

The drill bits 30 are directed against each other on the tool holder 10 and tilted by the angle of attack α relative to the rotation axis R inwards. The drill bits are each designed differently in the region of their side surface 31, so that the circumferential rows of hard material elements 14 of a drill bit 30 can each run into a groove 32, 33 of the adjacent drill bit 30.

The Harstoffelemente 34 are inserted into receptacles of the outer surface 31 of the drill bit 30 and soldered therein. As can be seen in FIG. 2, the outer row of hard material elements 34, that is, the row which surrounds the region of the groove 35 in an annular manner, are designed such that upon rotation of the drill bit 30 the hard material elements 34 project radially over the lateral surface 25. For this purpose, the hard elements 34 are arranged with respect to their Mitteilängsachsen relative to the central longitudinal axis ML of the drill bit 30 at an obtuse angle and tilted outwards, as Fig. 2 reveals. As a result of the outwardly projecting hard material elements 34, a free-cutting effect is achieved, which protects the side surface 25.3 from frictional wear on the generated bore wall. During tool engagement, wear occurs on the drill bit. Accordingly, both the drill bit 30 and the bit carrier 20 and the tool holder 10 are continuously worn. Depending on the state of wear, both the tool holder 10 and the bit carrier 20 and the drill bit 30 can be replaced individually. For the tool change the drill head is separated from the drill lance, the screw connection between the mounting lug 1 and drill pipe solved. The bit carrier can then be solved by simply expelling the mounting sleeve from the bore receptacle 21.3 and can be removed from the tool holder 10. The drill bit 30 can be pressed off the bit carrier 20. In this case, the clamping element is deflected 39.1 due to the geometry of the grooves 26.5 and 35 radially inwardly and comes out of engagement with the groove 35 of the drill bit 30. Then the drill bit 30 can be deported from the bit carrier 20.

Claims

claims A bit carrier (20) for a drill head having a tool head (26) receiving a drill bit (30) and having a mounting portion for interchangeable coupling of the bit support (20), or  wherein the bit carrier (20) is connected to the mounting portion with a tool holder (10),  characterized,  the fastening section has a discharge surface (25.2) in the feed direction (V) at the front, which merges into a radially outer side surface (25.3). 2. Meißeiträger according to claim 1,  characterized,  that the discharge surface (25.2) extends to the connection region of the drilling tool (30). 3. Meißeiträger according to claim 1 or 2,  characterized,  that the discharge surface (25.2) is inclined in regions opposite to the feed direction (V). 4. bit carrier according to one of claims 1 to 3,  characterized, that in the transition region between the Ableitfläche (25.2) and the side surface (25.3) a reaming edge (25.6) is formed. 5. bit carrier according to one of claims 1 to 4,  characterized,  that the Ableitfiäche (25.2) is part of a plug-in approach (21) having a fastening receptacle (21.1) for interchangeable coupling to a tool holder 10. 6. bit carrier according to claim 4,  characterized,  that the fastening receptacle (21.1) is recessed into the insertion projection (21). 7. bit carrier according to one of claims 1 to 6,  characterized,  that the side surface (25.3) faces away from the discharge surface (25.2) and, opposite to the feed direction (V), merges into an open surface (25.4) which is oriented opposite to the feed direction (V). 8. bit carrier according to one of claims 5 to 7,  characterized,  the fastening mount (21.1) is arranged in the region between the deflecting surface (25.2) and the free surface (25.4). 9. bit carrier according to one of claims 5 to 8,  characterized, that the discharge surface (25.2) and / or the free surface (25.4) is arranged on a guide piece (22), and the guide piece (22) has a guide (22.1) of the fastening receptacle (21) 10. bit carrier according to one of claims 1 to 9,  characterized,  the fastening receptacle (21) has on opposite sides linear guides, in particular prism guides. 11. bit carrier according to one of claims 4 to 10,  characterized,  in that the insertion projection (21) is designed in such a way that the reaming edge (25.6) is arranged on a different pitch circle to form a free-cutting region than the region of the side face (25) which adjoins the reaming edge (25.6) directly or indirectly. 12. bit carrier according to one of claims 9 to 11,  characterized,  in that the front carrier area in the feed direction (V) has a larger construction height (d2) in the radial direction relative to the rear carrying area in the feed direction (V) and / or forms a larger wear volume. 13. bit carrier according to one of claims 1 to 12,  characterized,  that the side surface (25.3) in the connection region on the drill bit (30) has a verschißißschutzschicht (25.7), and / or  that the drill bit (30) in the connection region to the side surface (25.3) has a wear protection layer (30.1), and the wear protection layer (25.7, 30.1) is formed by a hard material element. 14. bit carrier according to one of claims 1 to 13,  characterized,  in that the fastening receptacle (21) is opened radially inwards. 15. Mißeiträger according to one of claims 1 to 14,  characterized,  that the drill bit (30) is equipped on its outer surface (31) with protruding hard material elements (34), and  a part of the hard material elements (34) is arranged so that upon rotation of the drill bit (30) it projects beyond the side surface (25.3) to form a free-cutting area.