WO2012152585A1

WO2012152585A1 - Hand-guided power tool with an excitation actuator that is capable of vibrating

Info

Publication number: WO2012152585A1
Application number: PCT/EP2012/057540
Authority: WO
Inventors: Dietmar Saur
Original assignee: Robert Bosch Gmbh
Priority date: 2011-05-11
Filing date: 2012-04-25
Publication date: 2012-11-15
Also published as: DE102011075682A1

Abstract

The invention relates to a hand-guided power tool (100) with a drive unit (200) for driving an insert tool (130) in a vibrating manner. The drive unit has at least one excitation actuator (205) which is capable of vibrating and which is coupled to a coupling element (210) in order to transmit vibrations onto the insert tool (130), said vibrations being generated by the excitation actuator (205) during the operation of the drive unit (200). The excitation actuator (205) has at least one excitation element (220, 230) which is designed so as to be flat at least in some regions and which is made of a piezoelectric material. The excitation element (220, 230) is clamped between the coupling element (210) and a clamping member (240) that lies face to face against the excitation element (220, 230), said clamping member (240) being directly fixed to the coupling element (210).

Description

description

title

Hand-held power tool with a vibratory excitation actuator prior art

The present invention relates to a hand-held power tool with a drive unit for oscillating drive of an insert tool having at least one oscillatory excitation actuator, which is coupled to a coupling element for transmitting vibrations to the insert tool, which are generated during operation of the drive unit of the excitation actuator, wherein the excitation actuator has at least one excitation element formed at least in regions, which is formed from a piezoelectric material.

Such hand-held power tools with drive units are known from the prior art, which have oscillatory excitation actuators and z. The excitation actuators have one or more disk-shaped piezoceramics, each of which is connected between the coupling element and an associated pressure plate of a drive unit corresponding drive unit are clamped, wherein the tension is effected via a screw head of a through the pressure plate and the piezoceramics through and screwed to the coupling element clamping screw.

A disadvantage of the prior art is that these drive units have an asymmetrical bias curve, since the screw head of such a clamping screw provides only a limited and insufficient contact surface and the printing plate may have an undesirable unevenness between this bearing surface and the piezoceramics.

Disclosure of the invention

An object of the invention is therefore to provide a new hand-held power tool with a drive unit, in which an improved bias of disk-shaped piezoceramics of an associated excitation actuator is made possible on a corresponding coupling element of the drive unit.

This problem is solved by a hand-held power tool with a drive unit for oscillating drive of an insert tool having at least one oscillatory excitation actuator, which is coupled to a coupling element for transmitting vibrations to the insert tool, which are generated by the excitation actuator during operation of the drive unit. The excitation actuator has at least one excitation element formed at least in regions, which is formed from a piezoelectric material. The excitation element is clamped between the coupling element and a clamping element lying flat against the excitation element. The tendon is attached directly to the coupling element.

The invention thus makes it possible to provide a hand-held electric tool with a drive unit, which has a simplified structure and can be realized with a reduced number of components, wherein an improved and at least substantially symmetrical bias behavior is realized with respect to the piezoelectric excitation elements.

The tendon is preferably at least partially disc-shaped.

Thus, a simple and robust tendon can be provided with an enlarged support surface.

According to one embodiment, the clamping member has a pin-like fastening member. On the coupling element, a recess is preferably provided, in which the mandrel-like fastening member can be fastened. The invention thus enables the provision of a stable and reliable tendon.

The mandrel-like attachment member is preferably an at least partially provided with an external thread threaded mandrel. The recess preferably has an internal thread which can be screwed to the external thread.

Thus, an improved parallelism between the tendon and coupling element to achieve a more homogeneous pressure build-up in the operation of the drive unit can be made possible in a simple manner.

The external thread and the internal thread are preferably formed as a fine thread.

Thus, an improved power structure of the drive unit can be made possible by a softer voltage increase in the operation of the power tool, which is made possible by the comparatively reduced thread pitch of the fine thread. In addition, a drive unit with a stable and robust construction can thus be made possible.

The mandrel-like attachment member preferably has at least partially a centering aid for axially parallel alignment of the mandrel-like attachment member in the recess.

Thus, an improved parallelism of the drive unit can be achieved in a simple manner.

The mandrel-like attachment member and the tendon are preferably integrally formed.

Thus, an uncomplicated and reliable tendon can be provided in which the mandrel-like attachment member is arranged at least substantially perpendicular to a support or pressure surface formed by the tendon. According to one embodiment, the coupling element has a pin-like fastening member and on the clamping member is provided a recess in which the pin-like fastening member can be fastened.

The invention thus makes it possible to provide a drive unit with a robust and compact structure in which a simple and inexpensive tendon can be used.

Thus, the tendon and the coupling element can be securely and reliably secured together.

Thus, an improved force build-up can be made possible by a softer voltage increase in the operation of the power tool, which is made possible by the reduced thread pitch of the fine thread. In addition, a drive unit with a stable and robust construction can thus be made possible.

The mandrel-like attachment member and the coupling element are preferably integrally formed. Thus, an uncomplicated and reliable coupling element can be provided, with which at least substantially parallel clamping of the excitation actuator is made possible. According to one embodiment, the excitation element is assigned at least one disc-shaped contact element provided with a holding geometry.

The invention thus makes possible a simple and rapid assembly of the drive unit, wherein a support of a friction moment acting on the excitation element can be achieved by the holding geometry and thus a

Applying Scheher forces on the excitation element can be efficiently prevented.

The coupling element preferably has a bearing groove for the oscillatable mounting of the drive unit on an associated tool housing.

Thus, a safe and reliable storage of the drive unit can be realized on the tool housing of the hand-held power tool.

The above-mentioned problem is also solved by a drive unit for a hand-held power tool, which is designed for oscillating drive of an associated insert tool and at least one oscillatory excitation actuator, which is coupled to a coupling element for transmitting vibrations to the insert tool, which during operation of the drive unit be generated by the excitation actuator. The excitation actuator has at least one excitation element formed at least in regions, which is formed from a piezoelectric material. The excitation element is clamped between the coupling element and a clamping element lying flat against the excitation element. The tendon is attached directly to the coupling element.

Brief description of the drawings

The invention is explained in more detail in the following description with reference to exemplary embodiments illustrated in the drawings. Show it: 1 is a partially sectioned side view of a hand-held electric tool with a drive unit according to the invention,

FIG. 2 is a perspective view of the drive unit of FIG. 1 according to a first embodiment; FIG.

3 is a sectional view of the drive unit of Fig. 2,

4 is a perspective view of the tendon of FIGS. 2 and 3,

5 is a perspective view of a drive unit according to a second embodiment,

Fig. 6 is a sectional view of the drive unit of Fig. 5, and

7 is a perspective view of the coupling element of FIGS. 5 and 6.

Description of the embodiments

FIG. 1 shows an example of a cutting device designed, hand-held power tool 100 with a formed like a cutting blade insert tool 130 and a tool housing 1 10. This forms illustratively an interior 1 15, in which at least partially a to the oscillating drive of the cutting blade 130th provided drive unit 200 is arranged, which has at least one oscillatory excitation actuator 205. In addition, a contact element 143, at least one electronic component 120 and, at least in sections, an operating button 150 are arranged in the inner space 15.

According to one embodiment, the cutting device 100 for mains-independent power supply is mechanically and electrically connectable to a battery pack 140. It should be understood, however, that the present invention is not limited to cordless cutters, but rather may be applied to a variety of handheld power tools that utilize a vibratory excitation actuator for vibratory driving of an associated insert tool, whether or not Power tool network-dependent or independent of the mains with the battery pack 140 is operable. For example, the present invention can also be applied to hand-held drilling and / or sawing tools in which a vibratory excitation actuator is used for the oscillating drive of an associated insertion tool.

The battery pack 140 is illustratively connected to the electronic component 120 via the contact element 143 and associated electrical lines 145. This example has a control unit 125 which is connected via electrical lines 129 to the control button 150, which is actuated from outside the tool housing 1 10 via an associated protective cover 160. In addition, the electronic component 120 z. B. connected via electrical lines 127 to the drive unit 200.

The drive unit 200 illustratively has a coupling element 210 designed to transmit vibrations to the cutting blade 130, which is provided at an axial end pointing away from the tool housing 110 with a fastening unit 260 to which the cutting blade 130 is fastened. Between an opposite, for example, in the interior 1 15 of the tool housing 1 10 arranged axial end of the coupling element 210 and a clamping member 240 of the excitation actuator 205 is clamped. The illustratively at least partially disc-shaped clamping member 240 is attached for this purpose according to an embodiment directly on the coupling element 210, z. B. screwed with this, as described by way of example in FIGS. 3 and 6. In addition, on the outer circumference of the coupling element 210 illustratively a web-like circumferential projection 212 is formed, via which the drive unit 200 is mounted to vibrate in a tool housing 1 10 formed on the annular groove 1 12, the example between an axial end of the tool housing 1 10 and one in the interior 1 15 trained, annular projection 1 14 is formed.

According to one embodiment, the excitation actuator 205 has at least one and illustratively two excitation elements 220, 230, which are plane or planar and are disk-shaped, for example, at least in some areas having a piezoelectric material and will therefore also be referred to below as "piezoresis." The excitation actuator 205 becomes successor An exemplary piezoelectric actuator and exemplary piezor rings or disks are described in WO 2010/076230 A1, the disclosure of which is explicitly included in the present application, so that a detailed description of the piezoactuator 205 or the piezor rings is provided 220, 230 and their functionality can be dispensed with.

The piezoring 220 is illustratively at least partially flat against the tendon 240 and / or the piezo ring 230 at. The piezoring 230 is also illustratively at least partially flat against the coupling element 210 at. Due to the direct attachment of the tendon 240 on the coupling element

210 are the piezo rings 220, 230 braced as described above between these two components.

In operation of the cutter 100, a user actuates the operating button 150 by pressing the protective cover 160, so that the electronic component 120 and thus the control unit 125 are powered by the battery pack 140. The powered control unit 125 controls the piezoelectric actuator 205 in such a way that it generates vibrations as described in WO 2010/076230 A1, which are transmitted to the coupling element 210 and from there to the cutting blade 130. In this case, the coupling element 210 designed as an interface to the cutting blade 130 preferably serves to reinforce a vibration amplitude generated by the piezoactuator 205.

2 shows the drive unit 200 of FIG. 1 with the coupling element 210, the piezoelectric actuator 205 provided with the at least partially planar piezo rings 220, 230 and the at least sectionally disc-shaped clamping member 240 according to a first embodiment. The coupling element 210 has the fastening unit 260 of FIG. 1, which is illustratively formed on a tapered axial end portion of the coupling element 210 and is provided for fastening the cutting blade 130 of FIG. 1.

The piezoactuator 205 has illustratively ring-shaped or disc-shaped contact elements 222 which are illustratively provided with electrical connections 522 (in FIG. 5) or 232 for the electrical contacting of the piezo rings 220, 230. In addition, the contact rings 222 z. B. holding members 224 and 234, which form a holding geometry, via a simple and quick installation of the drive unit 200 is enabled. It should be noted, however, that the terminals 522 (in FIG. 5) and 232 also serve as holding members or can form them. In this case, a support of an acting during assembly on the piezoresis 220, 230 friction torque on the holding members formed by the holding members 224, 234 holding geometry can be achieved, so that an application of Scheerkräften z. B. on the tendon 240 on the piezo rings 220, 230 can be efficiently prevented.

The tendon 240 illustratively has a polygonal opening 270, illustratively a hexagonal opening. In this can be a suitable tool for attachment, for. B. screw, the tendon 240 engage the coupling element 210.

According to one embodiment, an annular, groove-like recess 214 instead of the web-like projection 212 of FIG. 1 is provided on the coupling element 210, via which the drive unit 200 can be mounted on the tool housing 1 10 of FIG. For this purpose, z. B. the annular projection 1 14 of FIG. 1 engage in the annular Lagerungsnut 214.

FIG. 3 shows the drive unit 200 of FIG. 2 with the coupling element 210, the clamping element 240 and the piezoelectric actuator 205 provided with the piezo rings 220, 230, which holds the contact rings 222 with the electrical connections 522 (in FIG. 5), 232 and Holding members 224, 234 has. The contact rings 222 are illustratively arranged between the piezo rings 220, 230 and between the clamping member 240 and the piezo ring 230.

According to one embodiment, the clamping member 240 on a support or pressure surface 247 and a mandrel-like attachment member 280, the z. B. is at least partially provided with an external thread 282 threaded mandrel. Against the pressure surface 247 is a contact ring 222 and the piezo ring 230 at. The coupling element 210 illustratively has a bearing or pressure surface 295 and a recess 290, the z. B. is provided with an internal thread 292, in which the threaded mandrel 280 can be fastened or screwed. Against the pressure surface 295 of the piezo ring 220 is applied. The external thread 282 and the internal thread 292 can be designed as fine threads with a comparatively reduced thread pitch in order to improve the force build-up of the thread. drive unit 200 by a correspondingly soft voltage increase during operation of the power tool 100 of FIG. 1 to allow.

The threaded mandrel 280 is preferably formed integrally with the clamping member 240 and illustratively comprises, at least in sections, a centering aid 245. This is exemplified sleeve-shaped and arranged on the threaded mandrel 280 to allow its axially parallel alignment in the recess 290 of the coupling element 210. For this purpose, the sleeve-shaped centering aid 245 engages, at least in sections, in the coupling element 210 or its illustratively stepped recess 290. In addition, the piezo rings 220, 230 and the contact rings 222 are mounted on the sleeve-shaped centering aid 245, so that they can also be used as an insulation aid between the piezo rings 220, 230 when using a suitable material. Alternatively, a corresponding insulation between the piezo rings 220, 230 can also be achieved via a suitable air gap between the threaded mandrel 280 and the piezo rings 220, 230, wherein centering of the threaded mandrel 280 over its outer diameter is made possible, so that the centering aid 245 is merely an optional component is.

FIG. 4 shows the clamping member 240 of FIGS. 2 and 3 formed as an example in one piece with the threaded mandrel 280 of FIG. 3. FIG. 4 illustrates the pressure surface 247 of the clamping member 240 and the external thread 282 of the threaded mandrel 280.

5 shows a drive unit 500 with a coupling element 510, the

Piezoelectric actuator 205 of FIG. 1 to 3 and an at least partially discoidal clamping member 540 according to a second embodiment, with which the drive unit 200 of FIG. 1 can be realized. The coupling element 510 illustratively has a fastening unit 560, which is formed, for example, on a tapered axial end region of the coupling element 510 and is provided for fastening the cutting blade 130 of FIG. 1.

The piezoelectric actuator 205, which as described in FIGS. 2 and 3 has the at least partially planar piezoresis 220, 230 and the contact rings 222 provided with the connection 232 and a further connection 522 and the holding members 224, 234, is disposed between the clamping member 540 and the Contact element 510 clamped. For this purpose, the coupling element 510 illustratively has a dornarti- ges fastening member 580 which is fixed in an associated recess or opening 570 of the clamping member 540.

According to one embodiment, an annular, groove-like recess 514 is provided on the coupling element 510, via which the drive unit 500 can be mounted on the tool housing 1 10 of FIG. For this purpose, z. B. the annular projection 1 14 of Fig. 1 in the annular bearing groove 514 engage. FIG. 6 shows the drive unit 500 of FIG. 5 with the coupling element 510, the

Tensioning member 540 and provided with the piezo rings 220, 230 piezoelectric actuator 205. According to one embodiment, the coupling element 510 has a Auflagebzw. Pressure surface 595 and the mandrel-like attachment member 580 of FIG. 5, the z. B. is at least in sections with a male thread 582 versehe- threaded mandrel. Against the pressure surface 595 of the piezo ring 220 is located. The

Tensioning member 540 illustratively has a bearing or pressure surface 547 and the recess 570 of FIG. 5, the z. B. is provided with an internal thread 572, in which the threaded mandrel 580 can be fastened or screwed. Against the pressure surface 547 is a contact ring 222 and the piezo ring 230 at. The external thread 582 and the internal thread 572 may be formed as a fine thread with a comparatively reduced thread pitch, in order to allow an improved force buildup of the drive unit 500 by a correspondingly smooth voltage increase during operation of the power tool 100 of FIG.

The threaded mandrel 580 is preferably formed integrally with the coupling element 510 and illustratively comprises, at least in sections, a centering aid 545. This is exemplified sleeve-shaped and arranged on the threaded mandrel 580 to allow its axially parallel alignment in the recess 570 of the tendon 540. For this purpose, the sleeve-shaped centering aid engages

545 at least partially in the tendon 540 and its illustratively stepped recess 570 a. In addition, the piezoelectric rings 220, 230 and the contact rings 222 are mounted on the sleeve-shaped centering aid 545, so that they see when using a suitable material as insulation help between see the piezo rings 220, 230 application. Alternatively, a corresponding insulation between the piezo rings 220, 230 can also be provided via a NEN suitable air gap between the threaded mandrel 580 and the piezo rings 220, 230 can be achieved, with a centering of the threaded mandrel 580 is made possible over its outer diameter, so that the centering aid 545 is only an optional component.

FIG. 7 shows the coupling element 510 of FIGS. 5 and 6 formed as an example in one piece with the threaded mandrel 580 of FIGS. 5 and 6. FIG. 7 illustrates the pressure surface 595 of the coupling element 510 and the external thread 582 of the threaded mandrel 580.

Claims

claims

1 . Hand-operated power tool (100) with a drive unit (200; 500) for oscillating drive of an insert tool (130) having at least one oscillatory excitation actuator (205) with a coupling element (210; 510) for transmitting vibrations to the insert tool (130 ) which are generated by the excitation actuator (205) during operation of the drive unit (200; 500), the excitation actuator (205) having at least one excitation element (220, 230) formed at least in regions, which is formed from a piezoelectric material, characterized in that the excitation element (220, 230) is clamped between the coupling element (210, 510) and a clamping element (240, 540) lying flat against the excitation element (220, 230), wherein the clamping element (240, 540) directly adjoins the coupling element (210, 510) is attached.

2. Hand-held power tool according to claim 1, characterized in that the clamping member (240; 540) is formed at least partially disc-shaped.

3. Hand-held power tool according to claim 1 or 2, characterized in that the clamping member (240) has a pin-like fastening member (280) and on the coupling element (210) has a recess (290) is provided, in which the pin-like fastening member (280) attachable is.

4. Hand-held power tool according to claim 3, characterized in that the mandrel-like fastening member (280) is an at least partially with an external thread (282) threaded mandrel and the recess (290) with the external thread (282) screwed internal thread (292). Hand-held power tool according to claim 4, characterized in that the external thread (282) and the internal thread (292) are formed as a fine thread.

Hand-held power tool according to one of claims 3 to 5, characterized in that the mandrel-like fastening member (280) at least partially a centering aid (245) for axially parallel alignment of the mandrel-like fastening member (280) in the recess (290).

Hand-held power tool according to one of claims 3 to 6, characterized in that the mandrel-like fastening member (280) and the clamping member (240) are integrally formed.

Hand-held power tool according to claim 1 or 2, characterized in that the coupling element (510) has a pin-like fastening member (580) and on the clamping member (540) has a recess (570) is provided in which the mandrel-like fastening member (580) can be fastened.

Hand-held power tool according to claim 8, characterized in that the mandrel-like attachment member (580) is an at least partially with an external thread (582) provided threaded mandrel and the recess (570) with the external thread (582) verschaubbares internal thread (572). 10. Hand-held power tool according to claim 9, characterized in that the external thread (582) and the internal thread (572) are formed as a fine thread.

1 1. Hand-held power tool according to one of claims 8 to 10, characterized in that the mandrel-like fastening member (580) at least in sections a centering aid (545) for axially parallel alignment of the mandrel-like fastening member (580) in the recess (570).

Hand-held power tool according to one of claims 8 to 1 1, characterized in that the mandrel-like fastening member (580) and the coupling element (510) are integrally formed.

13. Hand-held power tool according to one of the preceding claims, characterized in that the excitation element (220, 230) at least one provided with a holding geometry (224, 234), disc-shaped contact element (222) is associated.

14. Hand-held power tool according to one of the preceding claims, characterized in that the coupling element (210; 510) has a Lagerungsnut (214; 514) for oscillatory mounting of the drive unit (200; 500) on an associated tool housing (1 10).

15. Drive unit (200, 500) for a hand-held power tool (100), which is designed to oscillate drive an associated insert tool (130) and has at least one oscillatable excitation actuator (205) which is connected to a coupling element (210; Vibrations to the insert tool (130) is coupled, which are generated by the excitation actuator (205) during operation of the drive unit (200; 500), wherein the excitation actuator (205) has at least one excitation element (220, 230) formed at least in regions a piezoelectric material is formed, characterized in that the excitation element (220, 230) between the coupling element (210; 510) and a surface against the excitation element (220, 230) adjacent clamping element (240; 540) is braced, wherein the tendon ( 240; 540) is attached directly to the coupling element (210; 510).