EP4400263A1 - Electric hand tool - Google Patents

Abstract

Electric hand tool (10) with at least two device parts (1, 2) mounted so as to be movable relative to one another, wherein a first device part (1) comprises a motor-gear unit with a tool holder, and a second device part (2) comprises a handle unit. The first (1) and the second device part (2) are coupled to one another via at least one vibration-reducing device (4) and border one another in an interface region (3) spaced apart by an air gap (31), wherein at least one sealing element having a brush seal (6) is present in the interface region (3).

Description

FIELD OF INVENTION

The present invention relates to an electric hand tool, in particular a hammer drill.

Rotary hammers and other power hand tools such as drills, sabre saws, circular saws, jigsaws, core drills and/or demolition hammers (for floors and walls) are continually being developed in terms of performance and weight aspects as well as ergonomics. In terms of ergonomics, the vibration loads on the user are a particular focus of development efforts. Unacceptably high vibration loads can cause serious health damage, including the so-called white finger disease, especially in professional users.

Therefore, hammer drills and other power hand tools are known in which devices for reducing vibration are arranged between the handle and the motor-gear unit. Such vibration reduction devices are designed to reduce the vibration load occurring on the handle by reducing the transmission of vibrations from the motor-gear unit over as wide a range as possible. The handle and the motor-gear unit are usually mounted so that they can move relative to one another, with spring and/or damper elements and possibly sliding elements being used that are adapted to a vibration spectrum that can be expected during operation. The required freedom of movement is achieved by an air gap that is present between the handle and the motor-gear unit. Since relative movements between the handle and the motor-gear unit occur in the area of the air gap during operation, the air gap is provided with an intrusion protection, for which a bellows seal is often used that completely or at least partially surrounds the air gap in the area of the interface between the handle and the motor-gear unit.

Alternatively or in addition to spring and/or damper elements for vibration decoupling, vibration dampers can also be used in power tools, which are Usually have spring-loaded counterweights to suppress the frequency ranges that dominate during operation.

Although a bellows seal of the air gap ensures effective protection against interference and also provides a reliable partial or complete fluidic or mechanical seal of the interface area, it is relatively stiff due to comparatively high internal and/or external friction, so that a not inconsiderable amount of vibrations are transmitted from the motor-gear unit to the handle via a bellows seal, which runs counter to the desired effect of the vibration reduction device.

Electric hand tools with bellows seals for vibration isolation of device components are known from the state of the art. Such electric hand tools are used, among other things, in EN 10 2006 060 652 A1 and EP 1 637 288 B1 described.

Furthermore, in known electric hand tools, such as rotary hammers, a cooling air flow is often sucked in via the interface area between the handle and the motor-gear unit, which is required for the thermal management of the electrical, electronic and/or mechanical components of the electric hand tool. For this reason, the sealing of the air gap must not only provide protection against intrusion, but also be as fluid-tight as possible. Air flow within the interface area is often implemented in such a way that the interface area is divided into a negative pressure area and a positive pressure area, for example by an air barrier made of a closed-cell foam material, in order to prevent bypass flows between a suction side and a pressure side of a cooling air blower. Such an air barrier represents another undesirable vibration coupling between the handle and the motor-gear unit.

An object of the present invention is therefore to provide an electric hand tool which is characterized by improved vibration decoupling of the handle.

DISCLOSURE OF THE INVENTION

Accordingly, an electric hand tool, in particular a hammer drill, is proposed which has two device parts which are mounted so as to be movable relative to one another. A first device part comprises a motor-gear unit with a tool holder and a second device part with a handle unit, wherein the first and the second device part are coupled to one another via at least one vibration-reducing device and adjoin one another in an interface region spaced apart by an air gap. In the interface region there is at least one sealing element which has or consists of a brush seal.

The use of a brush seal in the interface area has the advantage over a bellows seal that it causes very little friction in the functional contact, so that the vibration decoupling of the second part of the device with the handle unit is significantly improved. By appropriately designing the brush seal with regard to the number of bristles, bristle density, bristle diameter, bristle dimensions and bristle materials, the required tightness can be achieved and the penetration of particles into the interface area can be effectively prevented.

Furthermore, the bristles can each have a tip, with the tips of at least a portion of a total of bristles being in contact with one of the device parts. The tips can in particular be rounded. This can counteract premature and/or excessive wear in the sealing contact, so that the desired low friction values can be maintained over as long a period of use as possible.

In general, brush seals with the densest possible bristle coverage are preferred. For example, typical bristle diameters can be between 0.2 and 1.5 mm and typical bristle lengths between 5 and 30 mm.

A cross-section of the bristles of the brush seal can in particular be circular. However, it is also possible for a cross-section of the bristles to have a polygonal or elliptical shape. In particular, the cross-section of the bristles can be flattened, which means that the cross-section has a greater extension in a first direction than in a second direction. In other words, bristles designed as lamellae and/or filaments also fall under the definition of a brush seal to be applied here. A staggered bristle length and/or different material selection of the bristles of a brush seal can also be advantageously used for improved fluidic sealing and mechanical decoupling.

In a further development, the brush seal can comprise at least one brush strip, which is accommodated in particular in a receiving groove of the first and/or second device part. Alternatively or additionally, it can be provided that the brush strip is connected to the first and/or second device part via a snap-in or clip connection. A brush strip is understood to be a structural unit that comprises a large number of bristles and a bristle carrier that supports them. A receiving groove suitable for receiving the brush strip can be integrated into a first and/or second device part provided as an injection-molded part in a cost-effective and effort-efficient manner. The use of a snap-in or clip connection to fix the brush strip to the first and/or second device part offers the advantage of haptic and/or acoustic feedback in production, so that the intended fit of the brush strip can be ensured. In versions, the bristle carrier of the brush strip can be directly overmolded in an injection molding process during the manufacture of the first and/or second device part.

However, the invention is explicitly not limited to the aforementioned possibilities for fixing the brush seal to the first and/or second device part. Alternatively, the bristles forming the brush seal can also be directly overmolded individually or in groups during the manufacture of the first and/or second device part in an injection molding process or can be molded on as a second injection molding component. It is also possible to hold the bristles forming the brush seal to the first and/or second device part via a clamp connection.

According to a further embodiment, the brush seal comprises a plurality of bristles, wherein the bristles in particular comprise or consist of a plastic material, in particular a polyamide, such as an aramid, polytetrafluoroethylene, polybutylene terephthalate, polypropylene, polyethylene and/or polyethylene terephthalate. In the case of bristles in the form of lamellae and/or filaments, it is particularly suitable if they consist of a polyamide, a thermoplastic elastomer or a polypropylene.

Basically, the aim is to achieve the lowest possible coefficient of friction in the sealing contact between the brush seal and a corresponding contact surface. In some designs, the coefficient of friction of the material pairing can advantageously be less than 0.3. In other designs, the coefficient of friction can be between 0.3 and 0.4. In special designs, however, the coefficient of friction can also be above 0.4.

In a preferred embodiment, the electric hand tool comprises a housing with a first housing part, which forms the first device part, and with a second Housing part that forms the second device part. According to this embodiment, the interface area is therefore between two parts of the housing, so that two housing parts are sealed against each other by the brush seal.

In an alternative embodiment, the electric hand tool comprises a sub-chassis, which comprises the motor gear unit with the tool holder and forms the first device part, and a housing in which the sub-chassis is arranged and which forms the second device part. According to this embodiment, the interface area is therefore located within the housing, with the brush seal sealing the sub-chassis from the housing. In this case, the housing itself can be designed without an external air gap and/or without a division between "handle" and "device".

A sub-chassis is understood to be a component of the power tool that has the drive-relevant components, for example the gear/drive/impact mechanism unit, and is itself mounted in a movable, decoupled manner relative to the housing, with springs, plain bearings, foams or the like being used for decoupling. On the outside, the housing forms a unit in particular and is immobile or stationary in itself. According to this embodiment, the housing forms a formwork within which the sub-chassis can move in a decoupled manner, whereby a particularly effective vibration decoupling of the drive-relevant components is achieved and the rigidity of the housing can be increased.

According to a further embodiment, a fluid guide arrangement, in particular an air guide arrangement, is present within the housing, which comprises an air flow generator - such as a cooling air blower - which is coupled in particular to the motor-gear unit. The fluid guide arrangement, in particular an air guide arrangement, has an intake fluid path, in particular an intake air path, which runs at least partially through the interface area. The fluid guide arrangement, in particular an air guide arrangement, thus represents a cooling system via which the thermal management of the electrical, electronic and/or mechanical components of the electric hand tool is implemented in order to avoid overheating and to dissipate heat loads arising during operation of the electric hand tool to the outside of the housing. Since the intake fluid path, in particular the intake air path, runs at least partially through the interface area, the brush seal in the area of the interface area is involved in sealing the intake fluid path, in particular the intake air path.

In embodiments, it is also possible for the fluid guide arrangement to have an exhaust air path which runs at least partially through the interface region, so that the brush seal in the region of the interface region is then involved in sealing such an exhaust air path.

In embodiments comprising a sub-chassis, the brush seal may further advantageously be configured to separate an intake air path from an exhaust air path.

In embodiments, the air guide arrangement can comprise at least one intake opening in the housing, which is fluidically connected to the intake air path. More precisely, the intake opening is located upstream of the interface region. In particular, the intake opening can be located in the second housing part.

Furthermore, in embodiments within the housing there can be an electronic assembly that is operatively coupled to the motor-gear unit and that is located at least partially in the intake fluid path, in particular the intake air path. In particular, the electronic assembly can be located in the second housing part. In an operating state of the electric hand tool, the electronic assembly can be swept over by an air flow, in particular a cooling air flow, that is guided through the intake fluid path, in particular the intake air path, so that heat loads that arise in the electronic assembly can be effectively dissipated. The electronic assembly can, for example, have a switch, a control and/or regulating device, in particular comprising power electronics. The electronic assembly can have at least one heat sink to improve heat transfer to the cooling air flow. In a particular embodiment, the electronic assembly can be arranged in a so-called decoupled handle.

According to yet another embodiment, a negative pressure region, comprising a section of the intake fluid path, in particular intake air path, and a positive pressure region can be present in the interface region. The positive pressure region can have a section of a compressed air path. The negative pressure region and the positive pressure region are separated by an air bulkhead. The air bulkhead can comprise a brush seal. The negative pressure region is located in particular on a suction side of the air flow generator, while the positive pressure region is located on a pressure side of the air flow generator.

By designing the air barrier with a brush seal instead of the closed-cell foam material commonly used in the prior art, the vibration decoupling of the second device part, in particular the second housing part, with the handle unit can be further improved. The brush seal of the air barrier can be arranged either on the first device part or on the second device part, with the other device part providing a corresponding contact surface with which the brush seal is in sealing contact.

Alternatively or additionally, a peripheral seal can be present in the interface area, which seals the first and the second device part against each other at least partially, but in particular completely, wherein in particular the peripheral seal comprises a brush seal. In particular, the peripheral seal seals the first and the second housing part against each other at least partially, but in particular completely.

A circumferential seal in the interface area designed as a brush seal has significantly lower friction than the bellows seal commonly used in the state of the art, so that the vibration decoupling of the second part of the device with the handle unit can be further improved.

In embodiments, an overlapping area can be provided in the interface area, which extends across the air gap from one device part to the other device part and overlaps the brush seal from each device part, so that it is protected from direct external mechanical influences and the protection against interference is improved. In addition, such an overlapping area functions as a labyrinth seal, so that the sealing effect of the brush seal can be further improved. The overlapping area can be designed as a collar formed on a device part, encircling the interface area, which extends to the other device part, wherein the other device part is accommodated in an area enclosed by the collar. The brush seal of the peripheral seal can be arranged either on the first device part or on the second device part, wherein the other device part in each case provides a corresponding contact surface with which the brush seal is in sealing contact.

In a further embodiment, the fluid guide arrangement, in particular the air guide arrangement, can have at least one intake air line which extends in the interface area at least in sections from the first into the second device part or extends from the second into the first part of the device and thereby bridges the air gap. A section of the intake fluid path, in particular the intake air path, runs through the intake air line. The intake air line is preferably sealed from the part of the device into which it extends by a brush seal.

Advantageously, the air gap of the interface region according to this embodiment is not located in the intake fluid path, in particular the intake air path, so that a separation of the interface region into a negative pressure region and a positive pressure region is not necessary and, as a result, the air barrier can be omitted. According to this embodiment, the positive effect on the vibration decoupling of the second device part comprising the handle unit is therefore maximized.

For all possible arrangements or uses of the brush seal in the interface area described here, the sealing contact can be either radial or axial or a combination of radial and axial. A radial sealing contact tends to offer the advantage that even with relatively small bristle lengths, comparatively large relative movements between the device parts can be sealed safely and with little friction. With a radial sealing contact of the brush seal, it is advisable if a longitudinal axis of the bristles encloses a flat angle with the associated counter sealing surface, as this can further reduce the frictional forces that occur. An axial seal, on the other hand, has the advantage of being easier to integrate into the design, but may require longer bristle lengths. With an axial sealing contact of the brush seal, it is advisable if a longitudinal axis of the bristles encloses a flat angle with a surface normal of the associated counter sealing surface, as this can prevent the bristles from developing an unintentional spring effect in the sealing contact.

Regardless of whether the brush seal is axial, radial or combined radial-axial, it is advantageous if the outer/side surfaces of the bristles can slide on a counter sealing surface that is as smooth as possible. Alternatively or additionally, the sealing effect can be improved if adjacent bristles interlock.

In embodiments, the second device part can be movably mounted relative to the first device part at least along a tool axis of the motor-gear unit. In particular, the tool axis can be a longitudinal axis of the electric hand tool, so that the second device part can be moved relative to the first device part at least with a movement component in or parallel to the longitudinal axis. The mobility of the second device part relative to the first device part can also comprise a component transverse to the longitudinal axis, albeit with a smaller amount. In embodiments comprising a sub-chassis which forms the first device part, the first device part can be movably mounted at least along a tool axis of the motor-gear unit relative to the housing which forms the second device part.

In embodiments, the vibration reduction device can comprise at least one spring element, which is supported at one end on the first device part and at the other end on the second device part. The support of the spring element on the device parts can be direct or indirect, i.e. with the interposition of additional device components that direct a force flow to or from the spring element.

The at least one spring element can extend, for example, along the tool axis of the motor-gear unit. In some embodiments, the spring element is a compression spring, in particular a helical spring. In other embodiments, however, the spring element can also be designed as a torsion spring. Alternatively or additionally, the spring element can have or consist of a foam.

Furthermore, the vibration reduction device can comprise at least one damping element, which is supported at one end on the first device part and at the other end on the second device part. The damping element is designed to dissipate kinetic energy absorbed by the spring element, so that uncontrolled oscillation can be avoided.

In embodiments, the second device part, in particular the second housing part, can be pivotably mounted on the first device part, in particular the first housing part, via at least one joint, wherein the joint in particular comprises the damping element, in particular in the form of a rotation damping element. The rotation damping element can in particular comprise or consist of a plastic material, wherein the plastic material can in particular provide a high internal damping.

According to yet another embodiment, at least one component of the vibration reduction device can be present in the interface region. In particular, the at least one spring element and/or the at least one damping element of the vibration reduction device can be present in the interface region. Alternatively, a component connected to the at least one spring element and/or the at least one damping element The force-conducting structure connected to the vibration reduction device must be present in the interface area.

SHORT DESCRIPTION OF THE CHARACTERS

Fig. 1

eine schematische Längsschnittansicht eines erfindungsgemäßen Elektrohandwerkzeugs gemäß einer ersten Ausführungsform;

Fig. 2

eine schematische Längsschnittansicht eines erfindungsgemäßen Elektrohandwerkzeugs gemäß einer zweiten Ausführungsform;

Fig. 3

eine schematische Längsschnittansicht eines erfindungsgemäßen Elektrohandwerkzeugs gemäß einer dritten Ausführungsform;

Fig. 4

eine schematische Längsschnittansicht eines erfindungsgemäßen Elektrohandwerkzeugs gemäß einer vierten Ausführungsform;

Fig. 5

Detail A aus Fig. 4 in einer isometrischen Ansicht;

Fig. 6

ein Ausschnitt einer schematischen Längsschnittansicht eines erfindungsgemäßen Elektrohandwerkzeugs gemäß einer fünften Ausführungsform;

Fig.7a,7b

jeweils eine schematische Ansicht möglicher Ausführungen einer Bürstendichtung eines erfindungsgemäßen Elektrohandwerkzeugs;

Fig. 8

Detailansicht einer Borste einer Bürstendichtung eines erfindungsgemäßen Elektrohandwerkzeugs.

The following description explains the invention using exemplary embodiments and figures. In the figures:

Fig.1

a schematic longitudinal sectional view of an electric hand tool according to the invention according to a first embodiment;

Fig.2

a schematic longitudinal sectional view of an electric hand tool according to the invention according to a second embodiment;

Fig.3

a schematic longitudinal sectional view of an electric hand tool according to the invention according to a third embodiment;

Fig.4

a schematic longitudinal sectional view of an electric hand tool according to the invention according to a fourth embodiment;

Fig.5

Detail A from Fig.4 in an isometric view;

Fig.6

a detail of a schematic longitudinal sectional view of an electric hand tool according to the invention according to a fifth embodiment;

Fig.7a,7b

each a schematic view of possible designs of a brush seal of an electric hand tool according to the invention;

Fig.8

Detailed view of a bristle of a brush seal of an electric hand tool according to the invention.

Identical or functionally equivalent elements are indicated by identical reference symbols in the figures, unless otherwise stated.

EMBODIMENTS OF THE INVENTION

Fig.1 shows an electric hand tool 10 according to the invention in the form of a hammer drill 10 in a first embodiment in a schematic longitudinal section. The hammer drill 10 has a housing and two device parts 1, 2 that are mounted so as to be movable relative to one another. A first device part 1 is designed as a first housing part 1 comprising a motor gear unit with a tool holder (not shown). A second device part 2 is designed as a second housing part 2 comprising a handle unit.

In the following description of the figures, the term housing parts 1,2 is used throughout for the device parts 1,2, which, however, does not explicitly limit the invention to this and merely serves to better understand the embodiments.

The first housing part 1 and the second housing part 2 are coupled to one another via a vibration reduction device 4 and are spaced apart from one another in an interface area 3 by an air gap 31. The vibration reduction device 4 comprises at least one compression spring element 41, via which the second housing part 2 is resiliently mounted relative to the first housing part 1. The vibration reduction device 4 also comprises a damping element 42, which is designed as a rotation damping element and is integrated into a joint 43, which pivotably couples the second housing part 2 to the first housing part 1. The second housing part 2 can be pivoted relative to the first housing part 1 by means of the joint 43 about the pivot point 431. Consequently, the vibration reduction device 4 allows a degree of freedom of movement of the second housing part 2 relative to the first housing part 1 at least along the tool axis or longitudinal axis L of the electric hand tool 10, more precisely a tilting/pitching movement about the pivot point 431.

An air guide arrangement is formed within the housing, which comprises an air flow generator (also not shown) coupled to the motor-gear unit (also not shown). The air guide arrangement comprises an intake air path C, which runs in sections through the interface area 3. In other words, cooling air is provided through the intake air path C through the interface area 3 or the air gap 31. The air guide arrangement represents a cooling air system via which the thermal management of the electrical, electronic and/or mechanical components of the power tool 10 is implemented in order to avoid overheating and to dissipate heat loads arising during operation of the power tool 10 to the outside of the housing.

The air guide arrangement draws the cooling air from outside the housing, namely through intake openings 21 in the second housing part 2, which are fluidically connected to the intake air path C and are located upstream of the interface region 3.

The interface area 3 is separated by an air bulkhead 32 into a negative pressure area 34, comprising a section of the intake air path C, and a positive pressure area 33, in order to avoid bypass flows between a suction side and a pressure side of the air flow generator, for example comprising a cooling air fan. The negative pressure area 34 is connected to a suction side of the air flow generator, while the positive pressure area 33 is connected to a pressure side of the air flow generator. According to the first embodiment, the air bulkhead 32 is formed from a particularly closed-cell foam material.

In order to achieve the lowest possible friction seal between the two housing parts 1, 2 in the interface area 3, there is a peripheral seal 5 in the interface area 3 that completely seals the two housing parts 1, 2 against each other, with the peripheral seal 5 having a brush seal 6. This allows a secure seal to be achieved for the section of the intake air path C running through the interface area 3 or a pressure-side section of the cooling air path. On the other hand, the vibration decoupling of the second housing part 2 is optimized by the very low-friction brush seal 6.

In order to prevent larger foreign bodies or body parts such as fingers from entering the interface area 3, an overlap area 8 is provided in the interface area 3, which extends across the air gap 31 from the first housing part 1 to the second housing part 2 and overlaps the brush seal 6 so that it is protected from direct external mechanical influences. In addition, the overlap area 8 functions as a labyrinth seal, which further improves the sealing effect of the brush seal 6. The overlap area 8 is designed as a collar formed on the first housing part 1, which surrounds the interface area 3 and extends to the second housing part 2, wherein the second housing part 2 is accommodated in an area enclosed by the collar. The brush seal 6 of the peripheral seal 5 is held on the first housing part 1. The second housing part 2 provides a corresponding contact surface on its outer circumference, with which the brush seal 6 is in sealing contact. Specifically, the brush seal 6 is arranged in a receiving groove 64 on the first housing part 1, wherein the receiving groove 64 is in particular on the collar of the Overlap section 8 is formed. The brush seal 6 of the peripheral seal 5 acts at least partially radially.

The electric hand tool 10 also has a handle 23 and an electrical connection cable 22 on its second housing part 2 comprising the handle unit, which supplies the energy required to operate the motor-gear unit. In an embodiment not shown in the figure, the electric hand tool 10 can also be designed as a battery-operated device and have an electrical energy storage device.

This in Fig.2 The electric hand tool 10 according to the invention shown in accordance with a second embodiment differs from the first embodiment in that the air barrier 32 is not formed by a foam material, but also comprises a brush seal 6. The air barrier 32 comprises a first partition wall 321 assigned to the first housing part 1 and a second partition wall 322 assigned to the second housing part 2. The first partition wall 321 and the second partition wall 322 partially overlap one another in the longitudinal direction L and are spaced apart from one another in the transverse direction. The second partition wall 322 carries a brush seal 6 which comprises a plurality of bristles which are in sealing contact with the first partition wall 321. In an embodiment not shown, however, the brush seal 6 can also be present on the first partition wall 321. Since an air barrier 32 made of foam material transmits vibrations from the first 1 to the second housing part 2 to a considerable extent, the vibration decoupling of the second housing part 2 with the handle unit can be further improved by designing the air barrier 32 with a brush seal 6.

This in Fig.3 The electric hand tool 10 according to the invention shown in a third embodiment differs from the first embodiment in that the brush seal 6 of the peripheral seal 5 is not radially effective but axially effective. The brush seal 6 is arranged in a circumferential receiving groove 64 formed on the second housing part 2, which is open in the longitudinal direction L, pointing towards the first housing part 1. Although an axially effective seal tends to require somewhat longer bristle lengths in order to compensate for the relative movements of the two housing parts 1, 2, such a seal can be integrated into existing devices in a structurally simpler manner if necessary.

This in Fig.4 The electric hand tool 10 in the form of a hammer drill 10 according to a fourth embodiment shown in a schematic longitudinal section differs from the first three embodiments largely due to a different air flow of the intake air path C of the air flow arrangement. The interface area 3 is not located in the intake air path C, but is bridged to a certain extent. The cooling air of the intake air path C is still sucked in through intake openings 21 provided in the second housing part 2. However, the air flow arrangement has an intake air line 9 through which a section of the intake air path C runs. The intake air line 9 extends in the interface area 3 at least in sections from the second housing part 2 into the first housing part 1 and in doing so bridges the air gap 31. More precisely, the intake air line 9 extends on an immersion section 91 from the second housing part 2 into the first housing part 1. The intake air line 9 is sealed off from the first housing part 1 by an intake air line seal 92, wherein the intake air line seal 92 comprises a brush seal 6. The brush seal 6 of the intake air line seal 92 is designed as a radially effective brush seal 6 in order to be able to optimally compensate for the relative movements of the two housing parts 1, 2 occurring in the interface area 3. Since the air gap 31 of the interface area 3 according to this embodiment is not located in the intake air path C, a separation of the interface area 3 into a negative pressure area and a positive pressure area is not necessary, so that the air barrier can be omitted. According to this embodiment, the positive effect on the vibration decoupling of the second housing part 2 comprising the handle unit is therefore maximized.

The intake air path C runs in the second housing part 2 comprising the handle unit via an electronic assembly 7 that is operatively coupled to the motor-gear unit and can be arranged in the handle unit. When the electric hand tool 10 is in an operating state, the electronic assembly 7 is swept over by a cooling air flow guided through the intake air path C, so that heat loads arising in the electronic assembly 7 can be effectively dissipated.

Fig.5 shows detail A from Fig.4 in an isometric view. Here, the area of sealing of the intake air line 9 with respect to the first housing part 1 by the intake air line seal 92 designed as a brush seal 6 is shown in an enlarged view. The bristles 61 of the brush seal 6 bridge a radial gap between the first housing part 1 and the intake air line 9 and lie sealingly against an outer circumference of the intake air line 9. This enables optimal relative freedom of movement of the intake air line 9 arranged on the second housing part 2 with respect to the first housing part 1, both in the longitudinal direction L and in the transverse direction Q.

This in Fig.6 The power hand tool 10 in the form of a hammer drill 10 according to a fifth embodiment, shown in detail in a schematic longitudinal section, differs from the fourth embodiment in that the second housing part 2 essentially has a C-shape. As a result, the second housing part 2 has a lower arm and an upper arm, both of which are coupled to the first housing part 1. The upper and lower arms of the second housing part 2 are in particular hollow. The lower arm of the second housing part 2 forms the intake air line 9 and is sealed from the first housing part 1 in a similar way to the fourth embodiment, namely by an intake air line seal 92 comprising a brush seal 6. However, according to the fifth embodiment, the upper arm of the second housing part 2 is also sealed from the first housing part 1 by an intake air line seal 92 comprising a brush seal 6. This makes it possible to use both the lower arm and the upper arm of the second housing part 2 as air-conducting device components of the air guide arrangement, while the advantageous effects on the reduced vibration coupling of the second housing part 2 described above are retained to the same extent.

Fig. 7a and Fig. 7b each show a schematic view of possible designs of a brush seal 6 of an electric hand tool 10 according to the invention. The brush seal 6 is designed as a brush strip 62. A brush strip 62 is understood to be a structural unit that comprises a plurality of bristles 61 and a bristle carrier 63 carrying them. The brush seals 6 act radially in both embodiments, but this is according to Fig. 7a arranged on a wall of the second housing part 2 and seals against a corresponding wall of the first housing part 1 while the brush seal according to Fig. 7b is arranged on a wall of the first housing part 1 and seals against a corresponding wall of the second housing part 2. In both embodiments, however, the brush seal 6 is designed to compensate for relative movements occurring between the housing parts 1, 2 in the longitudinal direction L and transverse direction Q and to cause as little friction as possible in order not to impair the vibration decoupling sought by the vibration reduction device 4.

Fig.8 shows a detailed view of a single bristle 61 of a brush seal 6 of an electric hand tool 10 according to the invention. The bristle 61 has a tip 611 which is rounded, which has the positive effect of reducing the frictional forces in the sealing contact and preventing premature and/or excessive wear in the sealing contact can be counteracted. Bristles 61 that interlock in the longitudinal direction are also conceivable.

LIST OF REFERENCE SYMBOLS

10

Power tool / hammer drill

1

First device part/housing part with motor-gear unit

2

Second device part/housing part with handle unit

21

Intake opening

22

Connection cable

23

Handle

3

Interface area

31

Air gap

32

Air bulkhead

321

partition wall

322

partition wall

33

Overpressure range

34

Negative pressure range

4

Vibration reduction device

41

Spring element

42

Damping element / rotational damping element

43

joint

431

pivot point

5

Perimeter seal

6

Brush seal

61

Bristles

611

Great

62

Brush strip

63

Bristle carrier

64

Receiving groove

7

Electronic assembly

8th

Overtaking section

9

Intake air line

91

Immersion section

92

Intake air line seal

L

Longitudinal axis / tool axis

Q

Transverse direction

C

Intake fluid path/intake air path

Claims (15)

Electric hand tool (10), in particular hammer drill (10), having two device parts (1, 2) mounted so as to be movable relative to one another, wherein a first device part (1) comprises a motor-gear unit with a tool holder and a second device part (2) comprises a handle unit, wherein the first (1) and the second device part (2) are coupled to one another via at least one vibration-reducing device (4) and adjoin one another in an interface region (3) spaced apart by an air gap (31), wherein at least one sealing element is present in the interface region (3),
characterized in that
the sealing element has a brush seal (6). Electric hand tool (10) according to claim 1, comprising a housing with a first housing part (1) which forms the first device part (1), and with a second housing part (2) which forms the second device part (2). Electric hand tool (10) according to claim 1, comprising a sub-chassis which comprises the motor gear unit with the tool holder and forms the first device part (1), and a housing in which the sub-chassis is arranged and forms the second device part (2). Electric hand tool (10) according to claim 2 or 3, wherein a fluid guide arrangement, in particular an air guide arrangement, is present within the housing, which comprises an air flow generator coupled in particular to the motor-gear unit, wherein the fluid guide arrangement comprises an intake fluid path (C), in particular an intake air path (C), which runs at least partially through the interface region (3). Electric hand tool (10) according to claim 4, wherein the fluid guide arrangement comprises at least one suction opening (21) in the housing which is fluidically connected to the suction fluid path (C), the suction opening (21) being upstream of the interface region (3). Electric hand tool (10) according to claim 4 or 5, wherein an electronic assembly (7) operatively coupled to the motor-gear unit is present in the housing, which lies at least partially in the intake fluid path (C). Electric hand tool (10) according to one of claims 4 to 6, wherein in the interface region (3) there is a negative pressure region (34) comprising a section of the intake fluid path (C) and a positive pressure region (33), which are separated by an air bulkhead (32), wherein in particular the air bulkhead (32) has a brush seal (6). Electric hand tool (10) according to one of the preceding claims, wherein in the interface region (3) there is a peripheral seal (5) which seals the first (1) and the second device part (2) against each other at least partially, wherein in particular the peripheral seal (5) has a brush seal (6). Electric hand tool (10) according to one of claims 4 to 8, wherein the fluid guide arrangement has at least one intake air line (9) which extends in the interface region (3) at least in sections from the first device part (1) into the second device part (2) or from the second device part (2) into the first device part (1) and in the process bridges the air gap (31), wherein a section of the intake fluid path (C) runs through the intake air line (9), wherein in particular the intake air line (9) is sealed with respect to the device part (1, 2) into which it extends by a brush seal (6). Electric hand tool (10) according to one of the preceding claims, wherein the second device part (2) is movably mounted relative to the first device part (1) at least along a tool axis (L) of the motor-gear unit. Electric hand tool (10) according to one of the preceding claims, wherein the vibration reduction device (4) has at least one spring element (41) which is supported at one end on the first device part (1) and at the other end on the second device part (2), wherein the spring element (41) extends in particular along the tool axis (L) of the motor-gear unit. Electric hand tool (10) according to one of the preceding claims, wherein the vibration reduction device (4) has at least one damping element (42) which is supported at one end on the first device part (1) and at the other end on the second device part (2). Electric hand tool (10) according to one of the preceding claims, wherein the second device part (2) is pivotally mounted on the first device part (1) via at least one joint (43), wherein the joint (43) in particular comprises the damping element (42), in particular a rotation damping element (42). Electric hand tool (10) according to one of the preceding claims, wherein at least one component of the vibration reduction device (4) is present in the interface region (3), in particular wherein the at least one spring element (41) and/or the at least one damping element (42) of the vibration reduction device (4) or a force conducting structure connected to the at least one spring element (41) and/or the at least one damping element (42) of the vibration reduction device (4) is present in the interface region (3). Electric hand tool (10) according to one of the preceding claims, wherein the brush seal (6) has at least one brush strip (62) which is received in particular in a receiving groove (64) of the first (1) and/or second device part (2) and/or wherein the brush strip (62) is connected to the first (1) and/or second device part (2) via a snap-in or clip connection and/or wherein the brush strip (62) is injection-molded onto the first (1) and/or second device part (2) or is connected to the first (1) and/or second device part (2) by means of an injection-molding process

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