A handheld machine tool equipped with a mechanical rotary striking mechanism

Abstract

A handheld machine tool includes a tool holder (150) and a housing (110), in which a drive motor and a transmission (118) are disposed within the housing (110), a mechanical rotary impact mechanism (122) for strikingly driving the tool holder (150) is disposed corresponding to the transmission (118), and a receiving sleeve (299) is disposed corresponding to the tool holder (150), the transmission (118) and the mechanical rotary impact mechanism (122) are disposed within the transmission housing (119), and the mechanical rotary impact mechanism (122) is disposed corresponding to an impact body (210) and the receiving sleeve (299). In a handheld machine tool having an anvil (220), and an accommodating sleeve (299) supported radially within bearing elements (231, 232) fixed within a transmission housing (119) for rotational and axial movement, a buffer ring (270) is provided facing the striking body (210) within the transmission housing (119) and arranged at least partially axially between the anvil (220) and the bearing elements (231, 232), and the buffer ring (270) has an inner diameter (263) smaller than the outer diameter (262) of the bearing elements (231, 232).

Description

[Technical Field]

[0001] The present invention relates to a hand-held machine tool having a tool holder and a housing, in which a drive motor and a transmission are arranged, a mechanical rotary striking mechanism for strikingly driving the tool holder is associated with the transmission, a receiving sleeve is associated with the tool holder, the transmission and the mechanical rotary striking mechanism are arranged in the transmission housing, the mechanical rotary striking mechanism has a striking body and an anvil associated with the receiving sleeve, and the receiving sleeve is supported in a radial direction within a bearing element fixed in the transmission housing so as to be rotationally and axially movable.

[0002] The prior art discloses handheld machine tools configured as impact drivers with a mechanical rotary striking mechanism, which has a spring-loaded striking body and an anvil. During striking operation, the striking body of the mechanical rotary striking mechanism axially strikes the anvil, which generates undesired vibrations and force shocks on the transmission housing in addition to the desired driving impact.

[0003] Disclosure of the Invention The present invention relates to a handheld machine tool having a tool holder and a housing, in which a drive motor and a transmission are arranged, a mechanical rotary striking mechanism for strikingly driving the tool holder is associated with the transmission, a receiving sleeve is associated with the tool holder, the transmission and the mechanical rotary striking mechanism are arranged in the transmission housing, the mechanical rotary striking mechanism has a striking body and an anvil associated with the receiving sleeve, the receiving sleeve is supported in a radial direction within a bearing element fixed in the transmission housing so as to be rotationally and axially movable, and a damping ring is provided in the transmission housing facing the striking body and arranged at least partially axially between the anvil and the bearing element, the damping ring having an inner diameter smaller than the outer diameter of the bearing element.

[0004] With this configuration, the present invention provides a handheld machine tool equipped with a mechanical rotary striking mechanism in which the damping ring damps undesired vibrations and force shocks that occur when the striking body of the mechanical rotary striking mechanism axially strikes the anvil, thereby effectively preventing damage or destruction of the transmission housing that would otherwise occur due to the undesired vibrations and force shocks.

[0005] Preferably, the outer diameter of the buffer ring is greater than the outer diameter of the bearing element.

[0006] In this way, an arrangement of the damping ring radially outside the bearing element can be easily and simply achieved.

[0007] The inner diameter of the buffer ring is preferably larger than the inner diameter of the bearing element.

[0008] With this configuration, it is possible to easily support the bearing element in the axial direction by the damping ring.

[0009] According to one embodiment, the damping ring has anti-rotation elements on its outer periphery to form an anti-rotation device.

[0010] This arrangement provides a reliable and reliable anti-rotation device for the buffer ring.

[0011] Preferably, the anti-rotation element comprises at least one, preferably radially oriented, anti-rotation web.

[0012] With this arrangement, the anti-rotation device can be easily formed.

[0013] The transmission housing preferably has a receiving element corresponding to the anti-rotation element.

[0014] In this way, the positive-locking locking device can be easily and simply configured as an anti-rotation device.

[0015] According to one embodiment, the buffer ring has at least one notch between its outer diameter and its inner diameter.

[0016] In this way, an alternative anti-rotation device can be easily provided.

[0017] Preferably, the transmission housing has, on its inner side facing the tool holder, at least one ridge for locating in at least one notch of the damping ring.

[0018] In this way, an alternative anti-rotation device can be easily and simply constructed.

[0019] According to one embodiment, at least two bearing elements are provided, which are in axial contact with one another along the axis of rotation of the tool holder.

[0020] Such an arrangement can allow for a compact arrangement of the at least two bearing elements.

[0021] Preferably, the buffer ring comprises sheet steel and / or plastic.

[0022] In this manner, a simple and cost-effective buffer ring can be provided.

[0023] The invention will be explained in more detail in the following description with reference to an embodiment shown in the drawing. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram showing a schematic diagram of a handheld machine tool equipped with a mechanical rotary impact mechanism. [Figure 2] 2 is a longitudinal cross-sectional view of the mechanical rotary impact mechanism shown in FIG. 1 with a damping ring disposed within the transmission housing; [Figure 3] 3 is a perspective view of the buffer ring of FIG. 2 disposed within a transmission housing. [Figure 4] FIG. 4 is a perspective view showing the buffer ring of FIGS. 2 and 3. [Figure 5] FIG. 4 is a front view showing the transmission housing of FIGS. 1 to 3. [Figure 6] FIG. 7 is a vertical cross-sectional view of the transmission housing of FIGS. 1 to 3 and 6.

[0025] Description of Examples In the drawings, elements having the same or comparable function are given the same reference numerals and will be described in more detail only once.

[0026] 1 shows a handheld machine tool 100 provided with a tool holder 150, the handheld machine tool 100 having a housing 110 with a grip 126. According to one embodiment, the handheld machine tool 100 is mechanically and electrically connectable to a battery pack 130 for grid-independent power supply.

[0027] In the illustrated embodiment, the housing 110 contains an electric drive motor 114, which receives current from a battery pack 130, a transmission 118, and a mechanical impact mechanism 122. The drive motor 114 can be operated, i.e., connected and disconnected, for example, via a hand switch 128 and may be of any motor type, such as an electronically commutated motor or a DC motor. Preferably, the drive motor 114 can be electronically controlled in an open or closed loop manner so that it can be operated in reverse and set to the desired rotation speed. The function and design of suitable drive motors are sufficiently known in the prior art and will not be described in detail here for the sake of brevity.

[0028] The drive motor 114 is preferably connected via an associated motor shaft 116 to a transmission 118, which preferably converts the rotation of the motor shaft 116 into the rotation of an intermediate shaft 120 arranged between the transmission 118 and a striking mechanism 122. This conversion preferably occurs so that the intermediate shaft 120 rotates with increased torque relative to the motor shaft 116, but at a reduced rotational speed. The drive motor 114 is arranged in a motor housing 115 in the illustrated embodiment. The mechanical striking mechanism 122 and / or the transmission 118 are arranged, for example, in a transmission housing 119. The transmission housing 119 and the motor housing 115 are arranged in the housing 110 in the illustrated embodiment. Alternatively, the mechanical striking mechanism 122 may be arranged in a separate striking mechanism housing.

[0029] The mechanical striking mechanism 122 coupled to the intermediate shaft 120 is, for example, a rotary striking mechanism, which generates a high-intensity rotary striking pulse and transmits it to the driven shaft 124, for example, to a driven spindle. Hereinafter, the mechanical striking mechanism will be referred to as the "mechanical rotary striking mechanism 122." In particular, the mechanical rotary striking mechanism 122 is provided to strike and drive the tool holder 150, and is disposed corresponding to the tool holder 150. In the illustrated embodiment, the mechanical rotary striking mechanism 122 has a spring-loaded striking body (210 in FIG. 2), which is connected to the intermediate shaft 120 and supported by the intermediate shaft 120 so as to be movable in the axial direction 102 of the transmission 118.

[0030] The driven shaft 124 is provided with a tool holder 150, which is preferably configured to receive a tool insert and, according to one embodiment, can be coupled to a tool insert 140 with an external polygonal connection. The tool insert 140 is configured, for example, as a screwdriver bit with an external polygonal connection, in the illustrated embodiment an octagonal connection. Such screwdriver bits are sufficiently known in the prior art that a detailed description thereof will not be provided here for the sake of brevity.

[0031] 2 shows the transmission 118 arranged in the transmission housing 119 shown in FIG. 1 and the rotary mechanical striking mechanism 122 with the intermediate shaft 120 shown in FIG. 1. As can be seen from FIG. 2, the mechanical striking mechanism 122 preferably has a spring-loaded striking body 210 and an anvil 220 that can be loaded by the striking body 210. The anvil 220 is preferably associated with the tool holder 150, in particular with a receiving sleeve 299 associated with the tool holder 150. The anvil 220 is preferably formed integrally with the receiving sleeve 299. In the illustrated embodiment, the anvil 220 is formed transversely, in particular substantially perpendicularly, to the receiving sleeve 299.

[0032] The mechanical striking mechanism 122 generates a high-intensity rotary impact pulse and transmits the rotary impact pulse to the driven shaft 124 or to the receiving sleeve 299 of the tool holder 150 via the anvil 220. A spring-loaded striking body 210 is supported movably in the axial direction 102 of the transmission 118. Such rotary mechanical striking mechanisms 122 are well known in the art and will not be described in detail here for the sake of brevity.

[0033] 1 can be placed in the receiving sleeve 299. The receiving sleeve 299 is supported for rotational and axial movement, preferably in the radial direction, in bearing elements 231, 232 fixed in the transmission housing 119. In the illustrated embodiment, the transmission housing 118 has two sections 291, 292 connected to one another. The section 291 is preferably formed as a cover fixed to the section 292.

[0034] According to the invention, a damping ring 270 is provided, which is preferably arranged in the transmission housing 119 and is designed to damp the impact energy transmitted by the impacting body 210 to the transmission housing 119. The damping ring 270 faces the impacting body 210 and is preferably arranged at least partially axially between the anvil 220 and the bearing elements 231, 232. At least one bearing element 231, 232 is arranged in a receiving portion 296 of the transmission housing 119 or of a section 292 of the transmission housing 119. At least one bearing element 231, 232 is also arranged radially between the transmission housing 118 and the receiving sleeve 299. In the illustrated embodiment, two bearing elements 231, 232 are arranged in the receiving portion 296 of the transmission housing 119. The two illustrated bearing elements 231, 232 are in axial contact with one another along the rotation axis 201 of the tool holder 150, i.e. the two bearing elements 231, 232 are in contact with one another. According to one embodiment, the bearing elements 231, 232 are configured as rolling bearings, in particular as ball bearings.

[0035] In the illustrated embodiment, the tool holder 150 has a longitudinal extension 203. It should be further noted that the term "axial direction" in the context of the present invention means a direction along the longitudinal extension 203 of the tool holder 150. Furthermore, the term "radial direction" means a direction approximately perpendicular to the longitudinal extension 203 of the tool holder 150. The radial direction 202 is therefore approximately perpendicular to the axial direction 102 of the transmission 118 or to the direction along the longitudinal extension 203 of the tool holder 150. Furthermore, the axial direction 102 is substantially parallel to the longitudinal extension 203 of the tool holder 150 or to the rotation axis 201 of the tool holder 150.

[0036] The buffer ring 270 preferably has an inner diameter 263 facing the receiving sleeve 299 and an outer diameter 264 facing away from the receiving sleeve 299. The inner diameter 263 is preferably smaller than the outer diameter 262 of the bearing elements 231, 232. Furthermore, the outer diameter 264 of the buffer ring 270 is preferably larger than the outer diameter 262 of the bearing elements 231, 232. Furthermore, the inner diameter 263 of the buffer ring 270 is preferably larger than or equal to the inner diameter 261 of the bearing elements 231, 232. This enables the buffer ring 270 to axially support the bearing element 231 in the region of its inner diameter 263.

[0037] According to one embodiment, the buffer ring 270 has on its outer periphery (301 in FIG. 3) an anti-rotation element 272 for forming an anti-rotation device together with the transmission housing 119. The anti-rotation element 272 preferably has at least one, preferably radially oriented, anti-rotation web 271. Preferably, the transmission housing 119 has a receiving element 282 that corresponds to the anti-rotation element 272. Preferably, the receiving element 282 is formed as a receiving part.

[0038] Alternatively or additionally, the buffer ring 270 has at least one notch 276 between its outer diameter 264 and its inner diameter 263. Likewise, the transmission housing 119, preferably in its section 292, has on its inner side 285 facing the tool holder 150 at least one ridge 284 for placement in the at least one notch 276 of the buffer ring 270. Preferably, the buffer ring 270 comprises sheet steel and / or plastic.

[0039] Figure 3 shows the damping ring 270 shown in Figure 2 arranged in section 292 of the transmission housing 119 shown in Figure 2. Figure 2 reveals damping ring 270 with anti-rotation element 272 arranged on its outer periphery 301. As described above, anti-rotation element 272 has at least one, preferably radially oriented, anti-rotation web 271.

[0040] In the illustrated embodiment, twelve anti-rotation webs 271 are arranged around the buffer ring 270 in the circumferential direction 305. However, any number of anti-rotation webs 271 may be provided. The anti-rotation webs 271 are preferably rectangular. Additionally, the anti-rotation webs 271 may have any shape, such as a triangular, polygonal, or semicircular shape. In the illustrated embodiment, the anti-rotation webs 271 have the same radial height in the radial direction 202. However, the anti-rotation webs 271 may have different radial heights in the circumferential direction 305. Preferably, all anti-rotation webs 271 have the same shape; however, the anti-rotation webs 271 may have different shapes in the circumferential direction 305.

[0041] FIG. 3 also shows a receiving element 282 corresponding to the anti-rotation element 272, located in section 292 of the transmission housing 119, for forming an anti-rotation device between the buffer ring 270 and the transmission housing 119. FIG. 3 also shows at least one notch 276 located between the outer diameter 264 and the inner diameter 263 of the buffer ring 270. In the illustrated embodiment, four notches 276 are located in the circumferential direction 305 of the buffer ring 270; however, the buffer ring 270 may have any number of notches 276. Each notch 276, for example, has an arcuate section 311 with side semicircular sections 312 in the illustrated embodiment. Correspondingly, section 292 or ridge 284 has an arcuate section 321 with side semicircular sections 322 in the illustrated embodiment. Similar to the anti-rotation elements 272, the notches 276 may have any shape. For example, the notches 276 may be rectangular, polygonal, elliptical, or circular. Furthermore, the notches 276 may be formed in different shapes along the circumferential direction 305 of the buffer ring 270.

[0042] Furthermore, the anti-rotation webs 271 and the notches 276 are diametrically opposed to one another; however, they may be irregularly spaced apart in the circumferential direction 305. Furthermore, the anti-rotation webs 271 may be diametrically opposed to one another, and the notches 276 may be irregularly spaced apart in the circumferential direction 305, or vice versa. In the illustrated embodiment, the notches 276 are located between the anti-rotation webs 271 and the inner diameter 263 of the buffer ring 270 in the radial direction 202. However, the notches 276 may be offset relative to the anti-rotation webs 271 in the circumferential direction 305.

[0043] Additionally, the buffer ring 270 may have anti-rotation elements 272 and / or at least one notch 276. That is, the buffer ring 270 may be formed solely with the anti-rotation webs 271 or solely with the notch 276.

[0044] According to another embodiment, the section 292 of the transmission housing 119 may have an anti-rotation element 272 and / or at least one notch 276, and the buffer ring 270 has a receiving element 282 corresponding to the anti-rotation element 272 and / or a ridge 284 arranged in correspondence with the notch 276.

[0045] Figure 4 shows the damping ring 270 shown in Figures 2 and 3 with an anti-rotation element 272 and a notch 276 for forming an anti-rotation device together with the transmission housing 119 shown in Figures 1-3. Figure 4 also shows the outer diameter 264 and the inner diameter 263 of the damping ring 270.

[0046] Figure 5 shows a section 292 of the transmission housing 119 of Figures 1 to 3. Figure 5 shows the receiving element 282 for receiving the anti-rotation element 272 of the damping ring 270 shown in Figures 2 to 4, as well as the raised portion 284 that corresponds to the recess 276 of the damping ring 270. For the sake of simplicity and clarity, only one of the four raised portions 284 in the illustrated embodiment is labeled with a reference number in Figure 5.

[0047] 6 shows section 292 of transmission housing 119 shown in FIG. 5, with pot-shaped base body 610, receiving element 282 and raised portion 284 arranged axially toward tool holder 150 shown in FIG. 2, and receiving portion 296 for arranging at least one bearing element 231, 232. Preferably, raised portion 284 forms an axial support for at least one bearing element 231, 232 that can be arranged in receiving portion 296, thereby preventing at least one bearing element 231, 232 from moving in axial direction 102 of transmission 118 toward drive motor 114 or to the left in the drawing. To this end, raised portion 284 partially closes receiving portion 296 in its radially outer region.

Claims

1. A handheld machine tool (100) including a tool holder (150) and a housing (110), wherein a drive motor (114) and a transmission (118) are disposed within the housing (110), a mechanical rotary impact mechanism (122) for strikingly driving the tool holder (150) is disposed corresponding to the transmission (118), and a receiving sleeve (299) is disposed corresponding to the tool holder (150), and a mechanical rotary impact mechanism (122) for strikingly driving the tool holder (150) is disposed corresponding to the receiving sleeve (299). a rotary striking mechanism (122) arranged in a transmission housing (119), the mechanical rotary striking mechanism (122) having a striking body (210) and an anvil (220) arranged corresponding to the receiving sleeve (299), the receiving sleeve (299) being supported in a radial direction within bearing elements (231, 232) fixed in the transmission housing (119) so as to be capable of rotational and axial movement; A buffer ring (270) is provided in the transmission housing (119) facing the striking body (210) and arranged at least partially axially between the anvil (220) and the bearing elements (231, 232), and the buffer ring (270) has an inner diameter (263) smaller than the outer diameter (262) of the bearing elements (231, 232). A handheld machine tool (100) characterized by:

2. 2. The handheld machine tool according to claim 1, wherein the outer diameter (264) of the buffer ring (270) is greater than the outer diameter of the bearing elements (231, 232).

3. 3. A handheld machine tool according to claim 1 or 2, wherein the inner diameter (263) of the buffer ring (270) is larger than the inner diameter (261) of the bearing elements (231, 232).

4. 4. A handheld machine tool according to claim 1, wherein the damping ring (270) has anti-rotation elements (272) on its outer periphery (301) to form an anti-rotation device.

5. 5. A handheld machine tool according to claim 4, wherein the anti-rotation element (272) comprises at least one, preferably radially oriented, anti-rotation web (271).

6. 6. A handheld machine tool according to claim 4 or 5, wherein the transmission housing (119) has a receiving element (282) corresponding to the anti-rotation element (272).

7. 7. The handheld machine tool according to claim 1, wherein the buffer ring (270) has at least one notch (276) between its outer diameter (264) and its inner diameter (263).

8. 8. The handheld machine tool according to claim 7, wherein the transmission housing (119) has, on its inner side (285) facing the tool holder (150), at least one ridge (284) for placement in the at least one notch (276) of the buffer ring (270).

9. 9. The handheld machine tool according to claim 1, wherein at least two bearing elements (231, 232) are provided, said bearing elements (231, 232) being in axial contact with one another along the rotation axis (201) of the tool holder (150).

10. 10. The handheld machine tool according to claim 1, wherein the damping ring (270) comprises sheet steel and / or plastic.

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