Hand-held power tool comprising a mechanical rotary percussion mechanism
Patent Information
- Application Number
- EP2023754727
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-09-07
- Filing Date
- 2023-08-04
- Publication Date
- 2025-07-16
AI Technical Summary
Hand-held power tools with mechanical rotary impact mechanisms experience unwanted vibrations and force shocks during the striking drive, which can lead to damage or destruction of the gearbox housing.
A buffer ring is introduced in the gear housing, positioned axially between the anvil and the bearing element, with an inner diameter smaller than the bearing element and an outer diameter larger than the bearing element, to dampen these vibrations and provide axial support, along with anti-rotation features to prevent twist and enhance locking.
The buffer ring effectively dampens unwanted vibrations and force shocks, preventing damage to the gearbox housing and ensuring safe operation by providing axial support and anti-rotation protection.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] title
[0003] Hand tool with a mechanical rotary impact mechanism
[0004] State of the art
[0005] The present invention relates to a hand-held power tool with a tool holder and a housing in which a drive motor and a gear are arranged, wherein a mechanical rotary impact mechanism for the impact drive of a tool holder is assigned to the gear, wherein a receiving sleeve is assigned to the tool holder, wherein the gear and the mechanical rotary impact mechanism are arranged in a gear housing, wherein the mechanical rotary impact mechanism has an impact body and an anvil assigned to the receiving sleeve, and wherein the receiving sleeve is mounted radially within a bearing element fixed in the gear housing so as to be rotatable and axially displaceable.
[0006] Such a handheld power tool, designed as a rotary impact wrench with a mechanical rotary impact mechanism, is known from the prior art. The mechanical rotary impact mechanism comprises a spring-loaded impact body and an anvil. In the percussive drive of the mechanical rotary impact mechanism, in which the impact body strikes the anvil axially, unwanted vibrations and force shocks are generated on the gear housing in addition to the desired drive impacts.
[0007] Disclosure of the invention
[0008] The invention relates to a hand-held power tool with a tool holder and a housing in which a drive motor and a gear are arranged, wherein a mechanical rotary impact mechanism for the percussive drive of a tool holder is assigned to the gear, wherein a receiving sleeve is assigned to the tool holder, wherein the gear and the mechanical rotary impact mechanism are arranged in a gear housing, wherein the mechanical rotary impact mechanism has an impact body and an anvil assigned to the receiving sleeve, and wherein the receiving sleeve is mounted radially within a bearing element fixed in the gear housing so as to be rotatable and axially displaceable. A buffer ring is provided which faces the impact body in the gear housing and is arranged at least partially axially between the anvil and the bearing element, wherein the buffer ring has an inner diameter that is smaller than an outer diameter of the bearing element.
[0009] The invention thus enables the provision of a handheld power tool with a mechanical rotary impact mechanism in which unwanted vibrations and force shocks generated by the mechanical rotary impact mechanism, in which the impact body axially impacts the anvil, are dampened by the buffer ring. This effectively prevents damage to or destruction of the gear housing as a result of unwanted vibrations and force shocks.
[0010] Preferably, an outer diameter of the buffer ring is larger than an outer diameter of the bearing element.
[0011] This makes it easy and straightforward to arrange the buffer ring radially outside the bearing element.
[0012] The inner diameter of the buffer ring is preferably larger than an inner diameter of the bearing element.
[0013] This makes it easy to provide axial support for the bearing element through the buffer ring.
[0014] According to one embodiment, the buffer ring has an anti-rotation element on its outer circumference to form an anti-rotation device.
[0015] This allows for a secure and reliable anti-rotation lock of the buffer ring. The anti-rotation element preferably has at least one, preferably radially aligned, anti-rotation rib.
[0016] This allows the anti-twist device to be designed in a simple manner.
[0017] The gear housing preferably has a receiving element corresponding to the anti-rotation element.
[0018] This makes it easy and uncomplicated to create a form-locking device that prevents rotation.
[0019] According to one embodiment, the buffer ring has at least one recess between its outer diameter and its inner diameter.
[0020] This makes it easy to provide an alternative anti-twist device.
[0021] Preferably, the gear housing has at least one elevation on its inner side facing the tool holder for arrangement in the at least one recess of the buffer ring.
[0022] This means that the alternative anti-twist device can be designed easily and simply.
[0023] According to one embodiment, at least two bearing elements are provided which are in axial contact along a rotation axis of the tool holder.
[0024] This enables a compact arrangement of at least two bearing elements.
[0025] The buffer ring preferably comprises sheet steel and / or plastic.
[0026] This allows for a simple and cost-effective buffer ring to be provided. Brief description of the drawings
[0027] The invention is explained in more detail in the following description using exemplary embodiments illustrated in the drawings. They show:
[0028] Fig. 1 is a schematic view of a hand tool with a mechanical rotary impact mechanism,
[0029] Fig. 2 is a longitudinal section through the mechanical rotary impact mechanism of Fig. 1 with a buffer ring arranged in a gear housing,
[0030] Fig. 3 is a perspective top view of the buffer ring of Fig. 2 arranged in the gearbox housing,
[0031] Fig. 4 is a perspective view of the buffer ring of Fig. 2 and Fig. 3, Fig. 5 is a front view of the gear housing of Fig. 1 to Fig. 3, and
[0032] Fig. 6 a longitudinal section through the gearbox housing of Fig. 1 to Fig. 3 and
[0033] Fig. 6.
[0034] Description of the embodiments
[0035] In the figures, elements with the same or comparable function are provided with identical reference symbols and are described in detail only once.
[0036] Fig. 1 shows a handheld power tool 100 provided with a tool holder 150, which has a housing 110 with a handle 126. According to one embodiment, the handheld power tool 100 can be mechanically and electrically connected to a battery pack 130 for mains-independent power supply.
[0037] Illustratively arranged in the housing 110 are an electric drive motor 114 supplied with power by the battery pack 130, a gear 118, and a mechanical percussion mechanism 122. The drive motor 114 can be actuated, i.e., switched on and off, via a manual switch 128, for example, and can be any motor type, e.g., an electronically commutated motor or a DC motor. Preferably, the drive motor 114 is electronically controllable or regulated in such a way that both reversing operation and specifications regarding a desired rotational speed can be implemented. The operation and structure of a suitable drive motor are sufficiently known from the prior art, so that a detailed description is omitted here for the sake of brevity.
[0038] The drive motor 114 is preferably connected via an associated motor shaft 116 to the gear 118, which preferably converts a rotation of the motor shaft 116 into a rotation of an intermediate shaft 120 provided between the gear 118 and the impact mechanism 122. This conversion preferably occurs such that the intermediate shaft 120 rotates relative to the motor shaft 116 with increased torque but reduced rotational speed. The drive motor 114 is illustratively arranged in a motor housing 115. The mechanical rotary impact mechanism 122 and / or the gear 118 are arranged, for example, in a gear housing 119. The gear housing 119 and the motor housing 115 are illustratively arranged in the housing 110. Alternatively, the mechanical rotary impact mechanism 122 can also be arranged in a separate impact mechanism housing.
[0039] The mechanical impact mechanism 122 connected to the intermediate shaft 120 is, for example, a rotary or rotational impact mechanism that generates high-intensity, sudden rotational pulses and transmits them to an output shaft 124, e.g., an output spindle. The mechanical impact mechanism is referred to below as the "mechanical rotary impact mechanism 122." In particular, the mechanical rotary impact mechanism 122 is provided for the impact drive of the tool holder 150 and is assigned thereto. The mechanical rotary impact mechanism 122 illustratively has a spring-loaded impact body (210 in Fig. 2) that is coupled to the intermediate shaft 120 and is mounted on the intermediate shaft 120 so as to be displaceable in the axial direction 102 of the gear 118.
[0040] Provided on the output shaft 124 is the tool holder 150, which is preferably designed to receive insert tools and, according to one embodiment, can be connected to an insert tool 140 with an external polygonal coupling. The insert tool 140 is designed, for example, as a screwdriver bit with an external polygonal coupling, illustratively an octagonal coupling. Such a screwdriver bit is sufficiently known from the prior art, so that a detailed description is omitted here for the sake of brevity. Fig. 2 shows the gear 118 arranged in the gear housing 119 of Fig. 1, as well as the mechanical rotary impact mechanism 122 with the intermediate shaft 120 of Fig. 1. Fig. 2 illustrates the mechanical rotary impact mechanism 122, which preferably has a spring-loaded impact body 210 and an anvil 220 that can be acted upon by the impact 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. The anvil 220 is illustratively formed transversely, in particular substantially perpendicularly, to the receiving sleeve 299.
[0041] The mechanical rotary impact mechanism 122 generates high-intensity, sudden rotational pulses and transmits them to the output shaft 124, or via the anvil 220 to the receiving sleeve 299 of the tool holder 150. The spring-loaded impact body 210 is displaceably mounted in the axial direction 102 of the gear 118. Such a mechanical rotary impact mechanism 122 is sufficiently known from the prior art, so a detailed description is omitted here for the sake of brevity.
[0042] The insert tool 140 of Fig. 1 can preferably be arranged in the receiving sleeve 299. The receiving sleeve 299 is preferably mounted radially within a bearing element 231, 232 fixed in the gear housing 119, so as to be rotatable and axially displaceable. Illustratively, the gear housing 118 has two interconnected sections 291, 292. Section 291 is preferably designed as a cover that is attached to section 292.
[0043] According to the invention, a buffer ring 270 is provided, which is preferably arranged in the gear housing 119 and is designed to dampen impact energy transmitted by the impact body 210 to the gear housing 119. The buffer ring 270 faces the impact body 210 and is preferably arranged at least partially axially between the anvil 220 and the bearing element 231, 232. The at least one bearing element 231, 232 is arranged in a receptacle 296 of the gear housing 119, or of the section 292 of the gear housing 119. In this case, the at least one bearing element 231, 232 is arranged radially between the gear housing 118 and the receiving sleeve 299. Illustratively, two bearing elements 231, 232 are arranged in the receptacle 296 of the gear housing 119. The illustrative two bearing elements 231, 232 are in axial contact along the rotation axis 201 of the tool holder 150, ie they lie against each other.According to one embodiment, the bearing elements 231, 232 are designed as rolling bearings, in particular ball bearings.
[0044] Illustratively, the tool holder 150 has a longitudinal extension 203. It should be noted that in the context of the present invention, the term "axial" is understood to mean a direction along the longitudinal extension 203 of the tool holder 150. Furthermore, the term "radial" is understood to mean a direction approximately perpendicular to the longitudinal extension 203 of the tool holder 150. Thus, the radial direction 202 is arranged approximately perpendicular to the axial direction 102 of the gear 118 or along the longitudinal extension 203 of the tool holder 150. Furthermore, the axial direction 102 is arranged substantially parallel to the longitudinal extension 203 of the tool holder 150 or parallel to a rotation axis 201 of the tool holder 150.
[0045] 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 an outer diameter 262 of the bearing element 231, 232. Furthermore, the outer diameter 264 of the buffer ring 270 is preferably larger than an outer diameter 262 of the bearing element 231, 232. Furthermore, the inner diameter 263 of the buffer ring 270 is preferably larger than or equal to an inner diameter 261 of the bearing element 231, 232. Thus, the buffer ring 270 can axially support the bearing element 231 at its inner diameter 263.
[0046] According to one embodiment, the buffer ring 270 has an anti-rotation element 272 on its outer circumference (301 in Fig. 3) for forming an anti-rotation lock with the gear housing 119. The anti-rotation element 272 preferably has at least one, preferably radially aligned, anti-rotation web 271. The gear housing 119 preferably has a receiving element 282 corresponding to the anti-rotation element 272. The receiving element 282 is preferably designed as a receptacle.
[0047] Alternatively or optionally, the buffer ring 270 has at least one recess 276 between its outer diameter 264 and its inner diameter 263. Analogously, the gear housing 119 preferably has at least one elevation 284 on its section 292 on its inner side 285 facing the tool holder 150 for arrangement in the at least one recess 276 of the buffer ring 270. The buffer ring 270 is preferably made of sheet steel and / or plastic.
[0048] Fig. 3 shows the buffer ring 270 of Fig. 2 arranged in the section 292 of the gear housing 119 of Fig. 2. Fig. 2 illustrates the buffer ring 270 with the anti-rotation element 272 arranged on the outer circumference 301. As described above, the anti-rotation element 272 has at least one, preferably radially aligned, anti-rotation web 271.
[0049] Illustratively, twelve anti-rotation webs 271 are arranged in the circumferential direction 305 of the buffer ring 270. However, any number of anti-rotation webs 271 can be provided. The anti-rotation webs 271 are preferably rectangular. It should be noted that the anti-rotation webs 271 can have any shape, e.g., triangular, polygonal, or semicircular. Illustratively, the anti-rotation webs 271 have the same radial height in the radial direction 202; however, the anti-rotation webs 271 can also 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 can also have different shapes in the circumferential direction 305.
[0050] Furthermore, Fig. 3 shows the receiving element 282 corresponding to the anti-rotation element 272 in section 292 of the gear housing 119 for forming an anti-rotation device between the buffer ring 270 and the gear housing 119. In addition, Fig. 3 shows the at least one recess 276 arranged between the outer diameter 264 and the inner diameter 263 of the buffer ring 270. Illustratively, four recesses 276 are arranged in the circumferential direction 305 of the buffer ring 270, but the buffer ring 270 can have any number of recesses 276. Each recess 276 has, for example, a circular arc-shaped section 311 with an illustrative lateral semicircular section 312. Accordingly, the section 292 or the one elevation 284 has a circular arc-shaped section 321 with an illustrative lateral semicircular section 322. Analogous to the anti-rotation element 272, the recess 276 can have any shape.For example, the recess 276 can be rectangular, polygonal, oval, or round. Furthermore, differently shaped recesses 276 can also be formed in the circumferential direction 305 of the buffer ring 270.
[0051] Furthermore, the anti-rotation webs 271 and the recesses 276 are arranged diametrically opposite one another, but can also be arranged at irregular intervals in the circumferential direction 305. Furthermore, the anti-rotation webs 271 can be arranged diametrically opposite one another and the recesses 276 can be arranged at irregular intervals in the circumferential direction 305, or vice versa. Illustratively, the recesses 276 are arranged in the radial direction 202 between the anti-rotation webs 271 and the inner diameter 263 of the buffer ring 270. However, the recesses 276 can also be arranged offset from the anti-rotation webs 271 in the circumferential direction 305.
[0052] It should be noted that the buffer ring 270 may have the anti-rotation element 272 and / or at least one recess 276. Thus, the buffer ring 270 may be formed only with the anti-rotation webs 271 or with the recesses 276.
[0053] According to a further embodiment, the section 292 of the gear housing 119 can have the anti-rotation element 272 and / or the at least one recess 276 and the buffer ring 270 has the receiving element 282 corresponding to the anti-rotation element 272 and / or the elevation 284 associated with the recess 276.
[0054] Fig. 4 shows the buffer ring 270 of Fig. 2 and Fig. 3 with the anti-rotation element 272 and the recesses 276 for forming an anti-rotation device with the gear housing 119 of Fig. 1 to Fig. 3. Furthermore, Fig. 4 illustrates the outer diameter 264 and the inner diameter 263 of the buffer ring 270.
[0055] Fig. 5 shows the section 292 of the gear housing 119 from Fig. 1 to Fig. 3. Fig. 5 illustrates the receiving element 282 for receiving the anti-rotation element 272 of the buffer ring 270 from Fig. 2 to Fig. 4, as well as the elevations 284 assigned to the recess 276 of the buffer ring 270. In Fig. 5, for the sake of simplicity and clarity, only one of the four illustrative elevations 284 is marked with a reference number.
[0056] Fig. 6 shows section 292 of the gear housing 119 of Fig. 5 with a pot-shaped base body 610 and the receiving element 282 arranged axially facing the tool holder 150 of Fig. 2 and the elevations 284, as well as the receptacle 296 for arranging at least one bearing element 231, 232. The elevations 284 preferably form an axial support for the at least one bearing element 231, 232 that can be arranged in the receptacle 296, whereby a displacement of the at least one bearing element 231, 232 in the axial direction 102 of the gear 118 towards the drive motor 114 or to the left, as shown in the illustration, can be prevented. For this purpose, the elevation 284 closes the receptacle 296 in sections at its radially outer region.
Claims
Claims 1. Hand-held power tool (100) with a tool holder (150) and a housing (110) in which a drive motor (114) and a gear (118) are arranged, wherein the gear (118) is assigned a mechanical rotary impact mechanism (122) for driving a tool holder (150) by impact, wherein the tool holder (150) is assigned a receiving sleeve (299), wherein the gear (118) and the mechanical rotary impact mechanism (122) are arranged in a gear housing (119), wherein the mechanical rotary impact mechanism (122) has an impact body (210) and an anvil (220) assigned to the receiving sleeve (299), and wherein the receiving sleeve (299) is mounted radially within a bearing element (231, 232) fixed in the gear housing (119) so as to be rotatable and axially displaceable, characterized by a buffer ring (270) which is arranged in the gear housing (119) facing the impact body (210) and at least partially axially between the anvil (220) and the bearing element (231 ,232), wherein the buffer ring (270) has an inner diameter (263) which is smaller than an outer diameter (262) of the bearing element (231, 232).
2. Hand tool according to claim 1, characterized in that an outer diameter (264) of the buffer ring (270) is larger than an outer diameter (262) of the bearing element (231, 232).
3. Hand tool according to claim 1 or 2, characterized in that the inner diameter (263) of the buffer ring (270) is larger than an inner diameter (261) of the bearing element (231, 232).
4. Hand tool according to one of the preceding claims, characterized in that the buffer ring (270) has on its outer circumference (301) an anti-rotation element (272) for forming an anti-rotation device.
5. Hand tool according to claim 4, characterized in that the anti-rotation element (272) has at least one, preferably radially aligned, anti-rotation web (271).
6. Hand tool according to claim 4 or 5, characterized in that the gear housing (119) has a receiving element (282) corresponding to the anti-rotation element (272).
7. Hand tool according to one of the preceding claims, characterized in that the buffer ring (270) has at least one recess (276) between its outer diameter (264) and its inner diameter (263).
8. Hand tool according to claim 7, characterized in that the gear housing (119) has on its inner side (285) facing the tool holder (150) at least one elevation (284) for arrangement in the at least one recess (276) of the buffer ring (270).
9. Hand tool according to one of the preceding claims, characterized in that at least two bearing elements (231, 232) are provided which are in axial contact along a rotation axis (201) of the tool holder (150).
10. Hand tool according to one of the preceding claims, characterized in that the buffer ring (270) comprises sheet steel and / or plastic.