WO2012079932A1

WO2012079932A1 - Portable power tool having a mechanical percussion mechanism

Info

Publication number: WO2012079932A1
Application number: PCT/EP2011/070751
Authority: WO
Inventors: Mohsein Wan; Chuan Cheong Yew; Chun How Low; Siew Yuen Lee; Chun Chee Loh
Original assignee: Robert Bosch Gmbh
Priority date: 2010-12-14
Filing date: 2011-11-23
Publication date: 2012-06-21
Also published as: EP2651604A1; DE102010063080A1

Abstract

In a portable power tool having a mechanical percussion mechanism (200), which has at least one percussive body (210, 220) that is provided with a drive cam (212, 222) and an output shaft (400) that is provided with at least one output cam (412, 422) and is connected to a tool mount (450) for holding a tool, wherein the drive cam (212, 222) is designed to drive the output cam (412, 422) in a percussive manner in percussive operation of the mechanical percussion mechanism (200), the output shaft (400) can be driven by a pot-like drive body (300) which encloses at least portions of the output shaft (400), wherein the at least one percussive body (210, 220) is arranged in a radially movable manner in the drive body (300) and has an opening (215, 225), through which the output shaft (400) reaches.

Description

description

title

Hand tool with a mechanical percussion prior art

The present invention relates to a portable power tool with a mechanical striking mechanism, which has at least one provided with a drive cam impact body and provided with at least one output cam output shaft which is provided with a tool holder for receiving a

Tool is connected, wherein the drive cam is formed for the striking drive of the output cam in the impact mode of the mechanical percussion. From DE 20 2006 014 850 U1 such, designed as a rotary impact wrench power tool is known, which has a mechanical percussion with a striker and an output shaft. In the non-impact operation of the rotary impact wrench, drive cams formed on the impactor engage in output cams provided on the output shaft such that rotational movement of the impactor is transmitted to the output shaft. In the percussion mode of the rotary impact wrench or of the percussion mechanism, the drive cams drive the output cams in an associated direction of rotation in a striking manner, with a respective impact generation each hammering a drive cam against an associated output cams.

A disadvantage of the prior art is that the impact generation in impact operation of the impact mechanism leads to a disturbing noise and thus to loss of comfort in the use of such a power tool.

Disclosure of the invention An object of the invention is therefore to provide a new hand tool that has a mechanical percussion that allows at least a reduction of noise in the impact mode.

This problem is solved by a hand tool with a mechanical striking mechanism, which has at least one provided with a drive cam impact body and provided with at least one output cam output shaft which is connected to a tool holder for receiving a tool. The drive cam is designed for the impact drive of the output cam in the impact mode of the mechanical impact mechanism. The output shaft is drivable by a pot-like drive body which surrounds the output shaft at least in sections. The at least one impactor is arranged radially displaceable in the drive body and has an opening through which passes through the output shaft.

The invention thus makes it possible to provide a hand tool with a mechanical striking mechanism, in which a Schluchtzeugung takes place both within a pot-like drive body and within an associated impact body, so that drive and impact body as damping members for

To reduce noise during beat generation.

According to one embodiment, the at least one impactor is supported via an associated spring element on the inner circumference of the pot-like drive body.

Thus, in a simple manner required for impact generation in impact operation of the mechanical percussion impact force of the impactor can be generated by spring action in the drive body.

The drive cam is preferably formed in the opening of the at least one impactor in the manner of a radially inwardly directed bulge.

Thus, a robust and compact drive cam can be provided on the impactor. According to one embodiment, the at least one impactor is supported via the associated spring element on the inner circumference of the drive body such that the spring element acts on the radially inwardly directed recess with a predetermined pressure force in the direction of the output shaft.

The invention thus enables a safe and reliable loading of the drive cam forming bulge in the direction of the output shaft. The at least one output cam is preferably formed on the outer circumference of the output shaft in the manner of a radially outward extension.

Thus, a simple and solid output cam can be provided on the output shaft.

According to one embodiment, the pot-like drive body has at least one guide recess, in which the at least one impact body is arranged rotationally fixed and radially displaceable. The invention thus enables a compact and robust construction of the mechanical impact mechanism.

The guide recess preferably has two guide walls oriented substantially parallel to one another, on which preferably two substantially parallel aligned side walls of the at least one

Impact body are slidably mounted.

Thus, the impactor can be stored in a simple manner sliding in the drive body.

The guide recess and the at least one impact body preferably each have an at least quadrangular cross section.

Thus, the provision of an uncomplicated and compact impact body and a simple and quickly formable guide recess can be made possible. According to one embodiment, at least a first and a second impact body are arranged in the pot-like drive body, which at least one first and a second output cam are assigned, which are formed on the output shaft.

The invention thus makes it possible in a simple manner to increase a corresponding rate of impact of the mechanical impact mechanism during impact operation.

The pot-like drive body is preferably non-rotatably connected to a drivable by an associated gear drive member.

Thus, a stable and inexpensive drive element for driving the drive body can be provided.

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 schematic view of a hand tool with an insertion tool according to an embodiment,

2 is an enlarged sectional view of a section of the hand tool of FIG. 1 according to an embodiment,

3 is an exploded perspective view of the arrangement of Fig. 2,

Fig. 4 is a first sectional view of the arrangement of Fig. 2 in the impact mode of the mechanical impact mechanism of Fig. 1 and 2, as seen in the direction of the arrows IV of Fig. 2, and

5 shows a second sectional view of the arrangement of FIG. 2 in the impact mode of the mechanical impact mechanism of FIGS. 1 and 2, as seen in the direction of the arrows IV of FIG. 2. Description of the embodiments

1 shows a hand tool machine 100 provided with a tool holder 450 and a mechanical percussion mechanism 200, which has a tool housing 110 with a handle 126. According to one embodiment, the handheld power tool 100 for mains-independent power supply can be mechanically and electrically connected to a battery pack 130.

The hand tool 100 is exemplified as a cordless rotary impact wrench. It should be noted, however, that the present invention is not limited to cordless impact drivers, but rather can be applied to various tools, particularly power tools, where a tool is rotated, e.g. For example, in a percussion drill, etc., regardless of whether the power tool is net inde pendent with a battery pack or network-dependent operable. In addition, it should be noted that the present invention is not limited to power tool hand tools, but is generally applicable to tools in which the hammer mechanism 200 described in FIGS. 2 to 5 may find application.

In the tool housing 1 10 a powered by the battery pack 130 with power, electric drive motor 1 14, a gear 118 and the hammer mechanism 200 are arranged. The drive motor 1 14 is z. B. via a manual switch 128 actuated, d. H. can be switched on and off, and can be any type of engine, eg. As an electronically commutated motor or a DC motor. Preferably, the drive motor 114 is so electronically controlled or controlled that both a reversing operation, as well as specifications with respect to a desired rotational speed can be realized. The operation and structure of a suitable drive motor are well known from the prior art and are therefore not further described here for the sake of brevity of the description.

The drive motor 114 is connected via an associated motor shaft 1 16 and an associated drive element 1 19 with the gear 118, the rotation of the motor shaft 1 16 in a rotation of a between transmission 1 18 and

Schlagwerk 200 provided drive member 120 converts. This conversion is preferably such that the drive member 120 rotates relative to the motor shaft 1 16 with increased torque, but reduced rotational speed. The drive motor 114 is illustratively arranged in a motor housing 115 and the transmission 1 18 in a housing 180, which is arranged with the motor housing 1 15 by way of example in the tool housing 1 10. It should be understood, however, that the transmission 118 and percussion mechanism 200 are merely illustratively disposed in the housing 180 and not for the purpose of limiting the invention. Rather, can transmission 1 18 and Schlagwerk 200 z. B. also be arranged in separate housings, which are arranged in the tool housing 110, or also directly in the tool housing 110th

The mechanical striking mechanism 200 connected to the drive member 120 is an example of a rotary striking mechanism. This is according to an embodiment for the generation of sudden high-intensity rotational pulses formed, which via an output cam assembly 410 to an output shaft 400, z.

As an output spindle can be transmitted. Illustratively, the hammer mechanism 200 has a drive body 300, which is connected in a rotationally fixed manner to the drive member 120. An enlarged view of a percussion 200, the output shaft 400 and the transmission 1 18 showing section 150 of the power tool 100 is illustrated in Fig. 2.

On the output shaft 400, the tool holder 450 is fixed, which is preferably designed for receiving insert tools and according to one embodiment with an insert tool 140 with a polygon socket coupling 142, z. B. a socket, connectable. The socket wrench 140 has, for example, a square coupling with bevelled edges, which is arranged on a suitable polygonal outer receptacle (451 in FIGS. 2 and 3) of the tool receptacle 450. Such a socket wrench is sufficiently known from the prior art, so that is omitted here for the sake of scarcity of the description to a detailed description.

FIG. 2 shows the detail 150 of FIG. 1 with the gear mechanism 118 and the mechanical percussion mechanism 200 of FIG. 1 in connection with the output shaft 400 in accordance with a first embodiment. The mechanical percussion mechanism 200, as described with reference to FIG. drive 1 18 connected drive body 300, in the illustratively two impactors 210, 220 are arranged.

According to one embodiment, the transmission 118 is a reduction gear, the z. B. is designed in the manner of a planetary gear and may have one or more planetary stages. Illustratively, the planetary gear 118 has a single planetary stage 201 with a sun gear 203, planetary gears 204, 205 and a planet carrier 207. The sun gear 203 is drivable by the drive member 119 of FIG. 1, which is rotatably connected to the motor shaft 1 16 or formed on this or can be formed integrally with this. The sun gear 203 and the drive element 119 are preferably also integrally formed. The planet gears 204, 205 are arranged in a ring gear, which is not shown for the sake of simplification of the drawing and z. B. rotatably in the tool housing 110 or the housing 180 of FIG. 1 is arranged.

The planet carrier 207 is illustratively connected to the drive member 120 and preferably integrally formed thereon or formed integrally therewith. According to one embodiment, the planet carrier 207 forms a front region 270 of the drive member 120. This front region 270 is designed as an example plate-shaped and flange-like and provided with a fastening device 240. On a - in Fig. 2 - axial side of the front portion 270 has a recess 470 for supporting the output shaft 400 is formed and on the opposite axial side of the front, flange-like portion 270 in a central, cylindrical portion 271 of the drive member 120 via. Radial recesses 252, 254 for receiving the planet gears 204 and 205, which are mounted on associated bearing bolts 278 and 279 in these recesses 252, 254, are provided in this middle region 271 by way of example. The bearing pins 278, 279 are z. B. in cylindrical openings 272, 274 and recesses 262, 264 rotatably mounted, so that by rotation of the planetary gears 204, 205 in the ring gear, not shown, a rotation of the drive member 120 can be effected. According to one embodiment, the central region 271 extends into a rear, annular region 272 of the drive member 120, which illustratively forms a cavity 289 for receiving the sun gear 203 and the drive element 119. The drive member 120 and its planet carrier 207 is rotatably connected to this as described above for the rotary drive of the drive body 300. For this purpose, the drive body 300 has by way of example a counter-fastening device 340 cooperating with the fastening device 240 of the planetary carrier 207. The fastening device 240 and the counter-fastening device 340 together form, for example, B. a press connection. It should be noted, however, that other types of connection are possible, for. B. threaded, clamping, latching or tooth-tooth gaps connections that allow a rotationally fixed connection between the planet carrier 207 and drive body 300. Further alternative fastening means for the rotationally fixed attachment of the drive member 120 to the drive body 300 are described by way of example in FIG.

According to one embodiment, the output shaft 400 has a shaft body 250 provided with an annular shoulder 255, which has an outer periphery 405. On the shaft body 250, the output cam assembly 410, which has at least one and preferably two output cam 412, 422, and the tool holder 450 of FIG. 1 are provided. The output cams 412, 422 are illustratively formed on the outer circumference 405 of the output shaft 400 as radially outward extensions 414, 424. An exemplary embodiment of the output cams 412, 422 is shown in FIGS. 3 to 5. Illustratively, the tool holder 450 has a polygonal outer receptacle 451, preferably a square outer receptacle, which is provided in the radial direction with four preferably planar side surfaces which are connected to one another via bevelled edges. An axial end of the shaft body 250, on which the output cams 412, 422 are formed, is illustratively rotatably mounted in the recess 470 of the drive member 120.

The output shaft 400 is at least partially enclosed by the drive body 300 according to an embodiment. This is exemplified cup-shaped and has at a first axial end 351 on a cup bottom-like wall 350 which is provided with an opening 360. At its opposite axial end 352, the drive body 300 has an opening 305, on which the counter-fastening device 340 is formed. Illustratively, the drive body 300 has an inner circumference or an inner wall 310 and forms an inner space 320 in which the shaft body 250 with the two output cams 412, 422 of the output shaft 400 up to that provided on this Ring shoulder 255 is arranged so that the output shaft 400 is rotatably but axially immovably disposed in the drive body 300. Here, the annular shoulder 255 is exemplified at least in sections against the pot bottom-like wall 350.

According to one embodiment, the impactors 210, 220 are non-rotatably connected to the drive body 300, but slidably disposed in the radial direction of the drive body 300 and preferably at least substantially immovably within the interior 320 in its axial direction. The impactors 210, 220 illustratively each have an opening 215 and 225, respectively, through which the output shaft 400 passes.

In the opening 215, by way of example, the drive cam 212 of the impactor 210 is formed as a radially inwardly directed bulge 312. In addition, the impactor body 210 is supported via an associated spring element 218 on the inner circumference 310 of the drive body 300 such that the spring element 218 acts on the radially inwardly directed recess 312 of the impactor body 210 with a predetermined pressure force in the direction of the output shaft 400 or the associated output cam 412. Similarly, in the opening 215, the drive cam 222 of the impactor 220 is also exemplified as a radially inwardly directed bulge 314. In addition, the impactor 220 is also supported via an associated spring element 228 on the inner circumference 310 of the drive body 300 such that the spring element 228 acts on the radially inwardly directed recess 314 of the impact body 220 with a predetermined pressure force in the direction of the output shaft 400 or the associated output cam 422 ,

3 shows an exploded view of the arrangement of FIG. 2 with the drive body 300, the output shaft 400, the impact members 210, 220 and the drive member 120. FIG. 3 shows the exemplary embodiment of the output cams 412, 422 on the outer circumference 405 of the output shaft 400 as radially outwardly directed extensions 414, 424 and the drive cam 212, 222 in the openings 215, 225 of the impactors 210 and 220 as radially inwardly directed bulges 312 and 314 illustrates. According to one embodiment, the drive body 300 has in its inner space 320 at least one guide recess 499 formed with a quadrangular cross-section, which illustratively has two guide walls 497, 498 aligned substantially parallel to one another. In addition, the drive body 300 has, by way of example, two driving cutouts 397, 398, on which associated, axially aligned fastening bores are provided. For example, the driving recess 398 has an axial mounting hole 391.

The impactors 210, 220 each have, for example, a cuboid shape with a quadrangular cross-section and at least two substantially parallel aligned side walls 382, 384, and 386, 388, respectively. These side walls 382, 384, and 386, 388 illustratively form the longitudinal sides of the impactors 210, 220. Perpendicular thereto, wide sides 381, 387, referred to below as "foot sides", and broad sides 383, 385, referred to below as "head sides", are arranged , On the lying in the region of the drive cam 212, 222 head sides 383, 385 recesses for supporting the spring elements 218 and 228 are formed. Illustratively, a recess 395 is provided on the head side 385. According to one embodiment, the drive member 120 has one or more drivers, which are exemplified stepwise formed on the planet carrier 207 and each having an associated axial mounting hole. Illustratively, the drive member 120 has two drivers 348, 349, wherein the driver 348 has a mounting hole 393 by way of example.

In an exemplary assembly of the components shown in Fig. 3, first the output shaft 400 in the direction of an arrow 399 from the axial end 352 of the drive body 300 starting in this on and pushed through the opening 360 until its annular shoulder 255 against the pot bottom-like wall 350, the tool holder 450 is positioned outside and the output cam assembly 410 in the interior 320 of the drive body 300. Then, the spring element 218 is arranged on the impactor 210 and inserted with this in the guide recess 499, wherein the opening 215, the output shaft 400 engages around. Subsequently, the spring element 228 is arranged on the impactor 220, or in the recess 395 provided on its head side 385, and inserted into the guide recess 499 with it. pushed, wherein the opening 225, the output shaft 400 engages around. In the next step, the planetary gears 204, 205 with the bearing pins 278 and 279 fixed to the drive member 120, the driver 348, 349 are then arranged in the driving recesses 398 and 397. Finally, the drivers 348, 349 are secured in the driving recesses 398 and 397, z. B. with

Rivets or screws 392 and 394, wherein z. B. the rivet or screw 392 engages through the mounting hole 393 in the mounting hole 391.

4 shows the drive body 300 of FIG. 2 with the guide recess 499, in which the provided with the drive cams 212, 214 striker 210 and

220 of FIG. 2 are mounted radially movable, through the openings 215 and 225, the output cam 400 provided with the output cam 412, 422 passes through. According to one embodiment, the impactors 210, 220 are respectively slidably mounted on the guide walls 498 and 497 of the guide recess 499 on two substantially parallel side walls 382, 384 and 386, 388 (FIG. 3). The spring elements 218 and 228 acting on the striking elements 210, 220 in the direction of the output shaft 400 are illustratively fixed on the driving body 300 in associated recesses 448 or 495 and on the striking bodies 210, 220 in corresponding recesses 418 and 395, respectively (FIG. 3).

During normal operation of the hand tool 100 of FIG. 1, the drive member 120 of FIGS. 1 and 2 rotatably drives the drive body 300. This takes in the guide recess 499 non-rotatably mounted impactor 210, 220 with their drive cams 212, 222 abut against the output cam 412, 422 of the output shaft 400, so that the impactor 300 also causes the output shaft 400 in rotation. Thus, in the impact-free operation or normal operation of the power tool 100 of FIG. 1, a rotational movement of the drive member 120, z. B. in the direction of an arrow 401, transmitted via the drive body 300 and the impactor 210, 220 to the output shaft 400. If now the torque demand on the output shaft 400 increases abruptly and their rotation is thus blocked, the mechanical percussion 200 goes into a hammering operation, wherein the drive body 300 of the drive member 120 of Fig. 1 and 2 in the example shown in the direction of the arrow 401 is further rotated, as described below in Fig. 5. FIG. 5 shows the arrangement of FIG. 4, in which the impactors 210, 220 have been further rotated by the drive body 300 in the direction of the arrow 401. During this further rotation, the drive cams 212, 222 slide on the outer circumference 405 of the output shaft 400 and along the associated output cams 412, 422, the force exerted by the impact members 210, 220 on the associated spring elements 218 and 228, respectively, increasing. Thus, the spring elements 218, 228 are increasingly compressed until the drive cams 212, 222 have arrived at corresponding reversal points 442 and 444 of the output cams 412 and 422, whereupon the drive cams 212, 222 extend through extension of the spring elements 218 and 228 via the reversal points 442 , 444 slipping and the striking bodies 210 and 220 are accelerated with a comparatively large torque against the output cams 412 and 422, and thus perform against this a sliding rotary impact. Subsequently, the process described above is repeated.

In the reversing operation of the power tool 100 of FIG. 1, the normal operation and the impact operation are carried out in a similar manner. Thus, for the sake of conciseness of the description, a detailed description of the reversing operation can be dispensed with here.

Claims

claims

A handheld power tool (100) comprising a mechanical percussion mechanism (200) having at least one striker (210, 220) provided with a drive cam (212, 222) and an output shaft (400) provided with at least one output cam (412, 422), is connected to a tool holder (450) for receiving a tool (140), wherein the drive cam (212, 222) for the striking drive of the output cam (412, 422) is formed in the impact mode of the mechanical impact mechanism (200), characterized in that the output shaft (400) of a pot-like drive body (300) is driven, which drives the output shaft

(400) encloses at least in sections, wherein the at least one impactor (210, 220) is arranged radially displaceable in the drive body (300) and an opening (215, 225) through which the output shaft (400) passes.

2. Hand tool according to Claim 1, characterized in that the at least one impact body (210, 220) via an associated spring element (218, 228) on the inner periphery (310) of the pot-like drive body (300) is supported.

3. Hand tool according to Claim 1 or 2, characterized in that the drive cam (212, 214) in the opening (215, 225) of the at least one impact body (210, 220) in the manner of a radially inwardly directed bulge (312, 314) is formed is.

4. Hand tool according to claim 2 and 3, characterized in that the at least one impactor (210, 220) via the associated spring element (218, 228) on the inner circumference (310) of the drive body (300) is supported, that the spring element (218 , 228) the radially inwardly directed bulge (312, 314) with a predetermined compressive force in

Direction of the output shaft (400) acted upon. Hand tool according to one of the preceding claims, characterized in that the at least one output cam (412, 422) on the outer circumference (405) of the output shaft (400) in the manner of a radially outward extension (414, 424) is formed.

Powered hand tool according to one of the preceding claims, characterized in that the pot-like drive body (300) has at least one guide recess (499) in which the at least one impact body (210, 220) is arranged rotationally fixed and radially displaceable.

Powered hand tool according to claim 6, characterized in that the guide recess (499) has two substantially parallel aligned guide walls (497, 498) on which two substantially parallel aligned side walls (384, 382, 388, 386) of the at least one impactor body (210, 220) are slidably mounted.

Powered hand tool according to claim 6 or 7, characterized in that the guide recess (499) and the at least one impactor (210, 220) each have an at least quadrangular cross-section.

Hand tool according to one of the preceding claims, characterized in that in the pot-like drive body (300) at least a first and a second impact body (210, 220) are arranged, which at least a first and a second output cam (412, 422) are assigned, the are formed on the output shaft (400).

0. Hand tool according to one of the preceding claims, characterized in that the pot-like drive body (300) rotatably connected to one of an associated transmission (1 18) drivable drive member (120) is connected.