WO2009015924A1

WO2009015924A1 - Hand-held power tool comprising a spring unit

Info

Publication number: WO2009015924A1
Application number: PCT/EP2008/056781
Authority: WO
Inventors: Joachim Hecht; Gerd Schlesak; Klaus Kuespert
Original assignee: Robert Bosch Gmbh
Priority date: 2007-07-30
Filing date: 2008-06-02
Publication date: 2009-02-05
Also published as: RU2482957C2; RU2010107375A; CN101772401B; CN101772401A; EP2176036A1; DE102007035699A1; EP2176036B1

Abstract

The invention relates to a hand-held power tool, especially a hammer drill and/or chipping hammer, comprising a drive unit (10) and a percussion unit (12) which has a gear unit (14a, 14b, 14c) and a bidirectionally displaceable piston (18) that can be driven by the drive unit (10). The invention is characterized in that at least one spring unit (22a to 22j) is mounted in the effective direction between the drive unit (10) and the piston (18).

Description

HAND TOOL MACHINE WITH SPRING UNIT

State of the art

The invention relates to a hand tool according to the preamble of claim 1.

From DE 100 66 115 Al a generic hand tool is known. The hand tool has a drive unit arranged in a housing, with which a tool holder can be driven in a hammering manner. A part of the housing is designed as an actuating handle. In addition, the hand tool machine has a second handle, which is designed in particular for guiding or holding oscillating devices, in that the handle has a vibration damping device. For this purpose, the handle on a handle element, in which the damping device is integrated. Advantages of the invention

The invention is based on a hand-held power tool, in particular a rotary and / or chisel hammer, with a drive unit and a percussion unit, which has a gear unit and a piston which can be driven bidirectionally and can be driven by the drive unit.

It is proposed that at least one spring unit is provided in the effective direction of the drive unit between the drive unit and the piston. The solution according to the invention is suitable in principle for all hand-held power tools which appear suitable to the person skilled in the art with a striking mechanism unit. The drive unit acts on the piston via the gear unit with a drive force and is preferably designed as an electric motor. The term "spring unit" should be understood to mean, in particular, mechanical, hydraulic and / or pneumatic springs and gas cushions as well as all spring devices that appear meaningful to a person skilled in the art be understood. Under a "percussion unit" are in particular two designed as a piston and rack moving parts, which are axially in a separate, opposite the moving parts guide tube accommodated axially behind one another and axially, bidirectionally slidably guided, are understood, the racket in a known manner A "gear unit" is intended in particular to be a unit for transmitting the driving force of the drive unit and / or to the drive unit Conversion of the present as rotational or rotational movement driving force in a linear or lifting movement are understood. The gear unit may be formed by various, the expert appears to be useful transmission means, such as bearing axles, swash bearings, pulleys, eccentric discs, etc., but particularly advantageous at least partially by a shaft and / or by a gear, which in addition to a compact design also advantageous power flow can be achieved. In addition, it is possible to use all gear arrangements which appear reasonable to the person skilled in the art. In the present exemplary embodiments, the gear unit is formed by the following elements, namely the part of the motor shaft from an upper edge of the electric motor and the drive means for transmitting the driving force from the electric motor to the piston of the percussion unit drive-coupled further transmission means, such as a connecting rod. Preferably, the at least one spring unit is arranged in the gear unit. The term "in the gear unit" is to be understood in particular as meaning that the spring unit is arranged in front of and / or between and / or behind the elements forming the gear unit in the effective direction of the drive unit or gear unit As in the present exemplary embodiments, a motor shaft, which is expressly also to be regarded as part of the gear unit, makes it possible to design the drive unit in a particularly space-saving manner a "motor shaft", in particular a shaft, which can be understood directly by means of a turbine unit and / or with Tels an electromagnetic unit of the drive unit is driven.

Such a design allows a reduction of vibrations of the striking hand tool. About the

Drive unit, the piston is offset from a starting position in a reciprocating, axial stroke movement in the guide tube, wherein an air cushion is alternately compressed and relaxed in a compression space. The racket is accelerated by the compression pressure and gives its energy in the form of a punching power to a tool. By installing the spring unit between the piston and the drive unit, force peaks caused by the compression pressure are reduced. As a result, the acceleration of the hand-held power tool drops, as a result of which advantageously the required driving force of the drive unit can be reduced while maintaining the percussion power of the club. The fact that the at least one spring unit can be integrated into an existing construction, this has no effect on the overall length of the power tool or on the gear unit of the power tool. The vibration damping takes place here advantageously without the expenditure of additional energy. The vibration damping system according to the invention responds directly to the compression pressure, so that the system is independent of the mode and the load on the transmission of the power tool.

It is further proposed that the transmission unit is an eccentric drive with an eccentric pin, a connecting rod and a piston pin, wherein the spring unit between the eccentric pin and the connecting rod and / or between the connecting rod and the piston pin and / or in the connecting rod and / or between the piston pin and the piston is provided. These embodiments make it possible to integrate the spring unit into a common gear unit, in that only one component or a few components have to be adapted or supplemented.

It is also proposed that the transmission unit is an eccentric drive with an eccentric disk which has a drive disk and an output disk coupled to the drive disk, wherein the drive disk is at least partially coupled to the output disk via the at least one spring unit. As a result, the vibration damping is integrated into the eccentric disc in a space-saving and cost-effective manner. In addition, the eccentric disc is carried out particularly stable by the two-part design and the integration of the spring units. Advantageously, spring units are provided which have either one effective direction or two effective directions.

In a further embodiment, it is proposed that the transmission unit is an eccentric drive with an eccentric disc and a rotatably mounted lever, wherein the lever is at least partially designed as a spring unit. As a result, the lever advantageously fulfills two functions, in that it transmits movements and also serves for damping.

In further embodiments, it is proposed that the gear unit is a wobble drive with a an intermediate shaft mounted, a wobble finger having swash bearing is, wherein the spring unit between the swash bearing and intermediate shaft and / or between wobble finger and piston is arranged. In the first case, the swash bearing is supported by the spring unit on the intermediate shaft at high compression pressure. In the second case, the piston moves directly against the spring unit at high compression pressure. Advantageously, in both cases, a high compression pressure can be compensated.

It is further proposed that the gear unit is a wobble drive with a swash bearing, wherein the spring unit is part of the swash bearing or the wobble finger. Preferably, the spring unit is designed as a spring plate, which is fastened with retaining rings on the swash bearing and additionally forms the wobble finger. The spring plate assumes a damping function due to its shape and material properties. This makes it possible to fulfill the damping function in a simple, cost-effective manner.

In a further embodiment, it is proposed that the gear unit is a wobble drive having a wobble bearing wobble bearing, wherein the wobble finger is at least partially designed as a spring unit, whereby a structurally simple and inexpensive damping is achieved.

Furthermore, it is proposed that the spring unit is at least one mechanical, hydraulic and / or pneumatic spring and / or a gas cushion. The free Selection of different types of springs allows a precise tuning of the damping system. About the type of spring unit both spring force and travel are selectable or adjustable.

It is also proposed that the spring unit is a compression spring, as a result of which the gear unit or the damping system can be manufactured in a structurally simple and particularly cost-effective manner.

In addition, it is proposed that the spring unit is an element made of an elastic material. As a result, a particularly cost-effective solution is possible because a simple production of the spring element can be carried out.

drawing

Further advantages result from the following description of the drawing. In the drawings, several embodiments of the invention are illustrated. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 is a schematic diagram of a part of a hand tool according to a first embodiment in a plan view with an eccentric 2 is a schematic diagram of the hand tool of FIG. 1 in a side view, the spring unit between an eccentric of the eccentric drive and a connecting rod of the percussion unit 3 shows the hand tool in a second embodiment with an eccentric drive, wherein the spring unit is provided between the connecting rod and the piston pin. FIG. 4 shows the hand tool in a third embodiment with an eccentric drive, wherein the spring unit is provided on the connecting rod 5 shows the hand tool in a fourth embodiment with an eccentric drive, wherein the spring unit is provided between the piston pin and the piston,

6 shows the hand tool in a fifth embodiment with an eccentric drive having an eccentric disc with a drive pulley and a driven pulley coupled to the drive pulley, wherein the drive pulley is coupled via the spring unit with the driven pulley,

6 shows the eccentric disk of FIG. 6, in which the spring unit has a direction of action, FIG. 8 shows the eccentric disk from FIG. 6, in which the spring unit has two effective directions, 9 is a spring unit made of elastic material,

10 is a spring unit with two compression springs,

Fig. 11, the hand tool in a sixth

Embodiment, wherein the spring unit is provided between see swash and intermediate shaft,

12 shows the handheld power tool in a seventh embodiment, wherein the spring unit is arranged between wobble finger and piston, FIG. 13 shows the handheld power tool in an eighth embodiment, wherein the spring unit is part of the wobble bearing,

Fig. 14, the spring unit of FIG. 13 in a first

Variant, Fig. 15, the spring unit of FIG. 13 in a second

Variant,

Fig. 16, the hand tool in a ninth embodiment, wherein the wobble finger is at least partially designed as a spring unit and

17 shows the hand tool machine in a tenth embodiment with an eccentric drive, which has an eccentric disk and a rotatably mounted lever, the lever being at least partially designed as a spring unit. Description of the embodiments

The figures show schematic diagrams of a part of a power tool designed as e¬ electric hammer. The electric hammer has a drive unit 10 arranged in a housing 48 and visible in FIGS. 1 and 11, and a hammer mechanism unit 12. The drive unit 10 is preferably designed as an electric motor. The drive unit 10 acts via a gear unit 14a, 14b, 14c on the hammer mechanism unit 12, wherein the gear unit 14a, 14b, 14c is formed in some embodiments as an eccentric drive and in other embodiments as a wobble drive.

The percussion unit 12 comprises two as pistons 18 and

Racket 20 trained moving parts, which are received axially in a separate, opposite the moving parts guide 16 axially behind each other and are guided axially, bidirectionally displaceable. The guide 16 is preferably formed as a tube. The drive unit 10 drives, via the gear unit 14a, 14b, 14c, the piston 18 which is displaceably arranged in the guide tube 16.

A first end face of the piston 18 and a first end face of the racket 20, which face each other, define a compression space 50 in which an air cushion is enclosed. An axis of the guide tube 16 is aligned with the axis of a tool holder, not shown, in which a tool is receivable. A rotary motion transmitted from the engine 10 to the gear unit 14a, 14b, 14c becomes a linear stroke of a connecting rod 26a to 26g reacted and transmitted via the piston 18 to the racket 20.

When the piston 18 moves backwards, a negative pressure is created which pulls the racket 20 backwards. During a forward movement of the piston 18 creates an overpressure between the piston 18 and racket 20, which accelerates the racket 20 forward. The forward flying bat 20 strikes a firing pin, not shown here, and releases its kinetic energy. The pulse of the racket 20 is transmitted from the firing pin on the tool (drill or chisel) also not shown here.

Thus, the piston 18 is offset by means of the drive unit 10 from a starting position shown for example in FIG. 1 into a reciprocating, axial stroke movement in the guide tube 16, wherein the air cushion in the compression space 50 is alternately compressed and relaxed. The racket 20 is accelerated by the compression pressure and gives its energy to the tool.

In FIGS. 1 to 10, the gear unit 14a is designed as an eccentric drive. The gear unit 14a comprises a motor shaft 52, an eccentric disc 30a, 30b with an eccentric pin 24 and a connecting rod 26a to 26g with a piston pin 28. The eccentric disc 30a, 30b is driven by the motor 10 via the gear unit 14a. The eccentric disc 30a, 30b is mounted via an eccentric shaft 54 in the housing 48 of the power tool. To drive the motor shaft 52 via a pinion 58 with the eccentric disc 30a, 30b into engagement. The eccentric disk 30a, 30b is above the Exzen- bolt 24 connected to the connecting rod 22a to 22g. The connecting rod 22a to 22g is connected by the piston pin 28 with the piston 18 of the percussion unit 12, which is operatively connected to the racket 20 and acts on the racket 20.

In Fig. 17, the gear unit is also formed as an eccentric 14c and includes a motor shaft 56a, an eccentric shaft 54, mounted on the eccentric shaft 54 eccentric disc 30c and a rotatably mounted lever 46. The rotatably mounted in the housing 48 lever 46 in this case transmits the movement of the eccentric 30c directly on the piston 18th

In FIGS. 11 to 16, the gear unit 14b is formed by a wobble drive. The gear unit 14b comprises a motor shaft 56b, an intermediate shaft 40 and a wobble bearing 42a, 42b, 42c mounted on the intermediate shaft 40 with a wobble finger 44a, 44b, 44c. The electric motor 10 drives the motor shaft 56 b, which is connected via a pinion 58 with the intermediate shaft 40 in engagement. On the intermediate shaft 40, the swash bearing 42a, 42b, 42c is mounted, which causes via the tumble finger 44a, 44b, 44c, a conversion of a rotational movement of the intermediate shaft 40 in a reciprocating axial movement or stroke of the piston 18 in the guide tube 16.

In order to improve in particular the vibration behavior of the power tool or to reduce the vibration of the power tool, according to the invention at least one spring unit 22a to 22j provided in the effective direction of the drive unit 10 between the drive unit 10 and the piston 18. Preferably, the spring unit 22a to 22j is provided in the gear unit 14a, 14b, 14c.

In a first embodiment according to Figures 1 and 2, the spring unit 22a is provided between the eccentric pin 24 and the connecting rod 26a.

Alternatively, in a second exemplary embodiment according to FIG. 3, the spring unit 22a may be provided between the connecting rod 26b and the piston pin 28.

In a third embodiment according to FIG. 4, the spring unit 22a is provided on or in the connecting rod 26c, in that the connecting rod 26c is made in two parts and the spring unit 22a is provided between the two parts. As a result, the two parts of the connecting rod 26c can be moved against each other.

Furthermore, in a fourth exemplary embodiment according to FIG. 5, the spring unit 22a can be arranged between the piston pin 28 and the piston 18, in such a way that the piston pin 28 is displaceably mounted in the piston 18.

6 shows the hand tool machine in a fifth embodiment with a gear unit designed as an eccentric drive 14a, which has a two-part eccentric disk 30a, namely a drive disk 32a, 32b and an output disk 34 coupled to the drive disk 32a, 32b, wherein the drive disk 32a , 32b is coupled to the driven pulley 34 via the spring unit 22b, 22c. In this case, the motor shaft 52 drives the drive pulley 32 a, 32 b, which the Output disc 34 via the spring units 22b, 22c entrains. As a result, the force peaks caused by the compression pressure are also reduced. FIG. 7 shows the eccentric disk 30a from FIG. 6 in a first variant. In this case, two spring units 22b are provided between the drive pulley 32a and the driven pulley 34, which can effect the force reduction only in one effective direction or rotational direction 36. FIG. 8 shows the eccentric disk 30a from FIG. 6 in a second variant. In this case, two spring units 22c are again provided between the drive disk 32b and the output disk 34, but these can cause a force reduction in two directions of action or directions of rotation 36, 38.

11 shows the handheld power tool in a sixth embodiment. Here, the spring unit 22a is arranged between the swash bearing 42a and intermediate shaft 40 such that the swash bearing 42a is at least partially supported on the intermediate shaft 40 via the spring unit 22a.

Fig. 12 shows the hand tool machine in a seventh embodiment, wherein the spring unit 22a between the wobble finger 44a and the piston 18 is arranged, preferably by the wobble finger 44a is connected via a wobble pin 60 with the piston 18 and the spring unit 22a between the wobble pin 60 and the piston 18 is arranged.

13 shows the handheld power tool in an eighth embodiment, wherein the spring unit 22f additionally forming the wobble finger 44b is part of the wobble bearing 42b. Here, the spring unit 22f is preferably designed as a spring plate, which, for example, with retaining rings 62nd is attached to the inclined swash bearing 42b. FIGS. 14 and 15 show two further variants, in which the spring unit 22g, 22h is part of the wobble bearing 42b.

16 shows the handheld power tool in a ninth embodiment, wherein the wobble finger 44c is at least partially embodied as a spring unit 22i in that the wobble finger 44c is designed as a resilient part, for example by suitable shaping and / or a suitable material selection.

17 shows the hand tool machine in a tenth embodiment with a gear unit designed as an eccentric drive 14c, which has the eccentric disk 30c and the rotatably mounted lever 46, wherein the lever 46 is at least partially designed as a spring unit 22j.

The at least one spring unit 22a to 22j may be at least one mechanical, hydraulic and / or pneumatic spring and / or a pressure pad. Preferably, the spring unit 22a to 22j is formed as a compression spring. Alternatively, according to FIG. 9, it may also be an element 22d made of a resilient material or according to FIG. 10 an element 22e with two spring elements lying opposite one another.

Claims

ROBERT BOSCH GMBH; D-70442 Stuttgart claims

1. Hand tool, in particular drill and / or chisel hammer, with a drive unit (10) and a percussion unit (12) having a transmission unit (14a, 14b, 14c) and one of the drive unit (10) drivable, arranged bidirectionally displaceable Piston (18), characterized by at least one spring unit (22a to 22j), which is provided in the effective direction of the drive unit (10) between the drive unit (10) and the piston (18).

2. Hand tool according to Claim 1, characterized in that the at least one spring unit (22a to 22j) in the gear unit (14a, 14b, 14c) is provided.

3. Hand tool according to Claim 1 or 2, character- ized in that it is in the gear unit (14a) to an eccentric drive with an eccentric pin (24), a connecting rod (26a - 26g) and a piston pin (28).

4. Hand tool according to Claim 3, characterized in that the spring unit (22a) is provided between the eccentric pin (24) and the connecting rod (26a) of the eccentric drive.

5. Hand tool according to Claim 3 or 4, characterized in that the spring unit (22 a) between the connecting rod (26 b) and the piston pin (28) of the eccentric drive is provided.

6. Hand tool according to one of claims 3 to 5, characterized in that the spring unit (22a) is provided in the connecting rod (26c) of the eccentric drive.

7. Hand tool according to one of claims 3 to 6, characterized in that the spring unit (22a) between the piston pin (28) of the eccentric drive and the piston (18) is provided.

8. Hand tool according to one of the preceding claims, characterized in that it is the gear unit (14a) is an eccentric drive with an eccentric disc (30a), which has a drive pulley (32a, 32b) and one with the drive pulley (32a, 32b) coupled output disk (34), wherein the drive pulley (32a, 32b) at least partially via the at least one spring unit (22b, 22c) is coupled to the driven pulley (34).

9. Hand tool according to Claim 1 or 2, characterized in that it is the gear unit (14c) is an eccentric drive with an eccentric disc (30c) acting on a rotatably mounted lever (46) on the piston (18), wherein the Lever (46) is at least partially designed as a spring unit (22j).

10. Hand tool according to claim 1 or 2, characterized in that it in the gear unit (14b) to a wobble drive with an intermediate shaft (40) mounted, a wobble finger (44a, 44b, 44c) having swash bearing (42a, 42b, 42c).

11. Hand tool according to one of claims 1, 2 or 10, characterized in that the swash bearing

(42a) on the spring unit (22a) on the intermediate shaft (40) at least partially supported.

12. Hand tool according to one of claims 1, 2 or 11, characterized in that the spring unit (22a) between the wobble finger (44a) and the piston (18) is arranged.

13. Hand tool according to one of claims 1, 2, 11 or 12, characterized in that the spring unit

(22f, 22g, 22h) is part of the wobble bearing (42b).

14. Hand tool according to one of claims 1, 2, 11, 12 or 13, characterized in that the wobble finger (44c) is at least partially designed as a spring unit (22i).

15. Hand tool according to one of the preceding claims, characterized in that it is the spring unit (22a to 22j) is at least one mechanical, hydraulic and / or pneumatic spring and / or a gas cushion.

16. Hand tool according to one of the preceding claims, characterized in that it is a compression spring in the spring unit (22a to 22j).