Handheld power tool

Abstract

The invention relates to a hand-held power tool (1) for at least partially axial strike material machining, comprising an inner housing (12) in which at least one strike mechanism (8) is arranged, and an outer housing (16) at least partially surrounding the inner housing (12). In order to decouple the axial movement of the inner housing (12) relative to the outer housing (16), a bearing (4) is arranged between the inner housing (12) and the outer housing (16). The bearing (4) comprises an elastic ring (20) applied to the inner housing (12) in which a plurality of sliders (24) are embedded on the outer circumferential surface, the plurality of sliders being in sliding contact with the outer housing (16).

Description

Technical field

[0001] The present invention relates to a hand-held power tool for at least partially axially impacting machining of materials, the hand-held power tool comprising an inner housing and an outer housing, at least one impact mechanism being arranged in the inner housing, the outer housing at least partially surrounding the inner housing. In order to disconnect the axial movement of the inner housing relative to the outer housing, a bearing is arranged between the inner housing and the outer housing.

[0002] The application field of the present invention is mainly extended to hand-held hammer drills or chipping hammers equipped with a drive device driven by an electric motor. Such electric hand-held tools generate a linear alternating working movement by means of a mechanical impact mechanism, i.e., a reciprocating movement to be applied to the tool, which is designed as a mortise chisel in the case of a chipping hammer and as an impact drill in the case of a hammer drill, for working preferably on mineral materials such as stone, concrete, etc. Due to the interaction with the workpiece and the operator's arm system, as well as the internal mass and stiffness distribution, an electric hand-held tool capable of driving the tool with normal impacts has a complex vibration behavior, which must be suppressed as much as possible. Background art

[0003] EP 0059 230 B1 discloses a self-lubricating elastic bearing which will be inserted between two elements rotating relative to each other. The bearing consists of an elastomeric bearing bushing having an inner surface with a relatively low coefficient of friction and an outer surface arranged in a bearing housing, the inner surface interacting with the inner element or with an element firmly connected thereto. At least three protruding bearing surfaces are arranged on the outer surface of the bearing bushing or in the above-mentioned bearing housing in an angularly distributed manner so as to deform the inner friction surface of the bearing bushing, thereby ensuring its contact with the above-mentioned inner element along the axial preloading region of the bearing bushing, thus achieving the effect of centering and damping vibration of the two above-mentioned elements.

[0004] The object of the present invention is to provide a hand-held power tool by means of which vibration can be reduced by using simple technical means. Summary of the invention

[0005] This object is achieved by a hand-held power tool for at least partially axially impacting machining of materials according to the preamble of claim 1 in combination with its characterizing features. The following dependent claims describe advantageous developments of the present invention.

[0006] The present invention includes the following technical teachings: The bearing includes an elastic ring applied to the inner housing, in which a plurality of sliders are embedded on the outer circumferential surface, and these sliders are in sliding contact with the outer housing. Therefore, the radial vibration and impact between the inner housing and the outer housing can be mitigated by the compression of the elastic ring. In addition, the sliding bearing is simply constituted by the sliders, and through this sliding bearing, the axial movement of the inner housing relative to the outer housing can be disengaged. Therefore, various functions can be achieved by the sliding bearing designed in this way. Advantageously, the elastic material is an elastomer.

[0007] According to a preferred embodiment, the sliders are made of sintered material. The sliders are produced by a sintering process. Such a production process enables the sliders to be produced with simple technology. Such sliders still have a certain porosity after sintering. Due to this porosity, the lubricant is stored in the pores and the sliders can better provide the lubricant, so that the lubrication of the bearing can be improved by the sliders formed of sintered material.

[0008] According to another preferred embodiment, the sliders are formed of carbon fiber reinforced plastic. Components made of carbon fiber reinforced plastic are lighter than those made of metal. Therefore, the use of such sliders can make the weight of the handheld power tool lighter, thus improving the operability of such handheld power tools.

[0009] Preferably, a retaining device is arranged on the inner surface of the elastic ring, which interacts with the sliders such that the sliders are held in the cutouts of the elastic ring. The retaining device should be understood as any design of the elastic ring or a separately arranged component, which makes it more difficult to remove the sliders after the sliders are installed. After the sliders are inserted, such a retaining device ensures that the sliders do not accidentally fall off the elastic ring before the handheld power tool is fully assembled. Thereby, the assembly of the handheld power tool is simplified.

[0010] Alternatively or in addition, the sliders have a retaining device, which interacts with the elastic ring after the sliders are assembled such that the sliders are held in the cutouts of the elastic ring. The retaining device is advantageously designed as a stop lug. Therefore, the assembly of the handheld power tool can also be simplified by the retaining device on the sliders.

[0011] Advantageously, the elastic ring forms radially offset portions, wherein the sliders abutting against the outer housing are arranged in the radially outer portion, while the radially inner portion abuts against the inner housing. The elastic ring has a meandering shape. A portion is understood to represent a continuous region of the elastic ring having the same outer radius or inner radius. The radially inner portion has a smaller inner radius than the outer portion. Therefore, the outer portion does not abut against the inner housing. The elastic ring gives the sliders a spring effect, such that the sliders elastically abut against the outer housing. Thus, the inner housing is supported on the outer housing without clearance by the bearing. In addition, the radial vibration or impact can be absorbed by the spring effect.

[0012] Preferably, a defined recess is formed in the inner housing in the region below the slider such that the slider is elastically held between the inner housing and the outer housing by an elastic ring. The slider thus does not abut against the inner housing, such that the slider can move radially. Accordingly, here too, the bearing can be supported on the outer housing without play. Due to the spring effect of the slider, radial vibrations or shocks can be decoupled. Depending on the geometry of the selected elastomer, the geometry of the cutout in the inner housing, and the geometry of the elastomer material, the decoupling spring characteristic curve can be adjusted as required.

[0013] In an advantageous embodiment, the bearing is arranged in the region of the side handle fastener. The side handle fastener is a device by means of which the user can fix the side handle to the outer housing of the hand-held power tool by frictional connection after positioning. In the process, a retaining ring is usually fastened to the outer housing. Such fixing often causes deformation of the outer housing. According to the prior art, such deformation would result in non-uniform loading in this region. Due to the spring effect of the slider according to the invention, such deformation can be compensated such that, despite deformation of the outer housing, the outer housing can still be supported uniformly relative to the inner housing.

[0014] The elastic ring is advantageously arranged on the inner housing in a prestressed state. The inner radius of the elastic ring is slightly smaller than the outer radius of the inner housing. Accordingly, the elastic ring is applied to the inner housing in a stretched state. This prestressed state ensures that the spring effect can be directly and fully achieved by radially deflecting the slider embedded in the elastic ring. The spring force required for the slider can also be set by a certain degree of prestressing.

[0015] The hardness of the elastic material is preferably 70 to 90 Shore A hardness. Materials with such hardness have good damping values for damping vibrations and shocks of the hand-held power tool.

[0016] The elastic ring is preferably arranged in the recess of the inner housing. The inner housing thus has a recess that has at least the width of the elastic ring. The elastic ring is thus held in place by the recess and therefore does not become misaligned. Accordingly, it can be ensured that the elastic ring is permanently held in the predetermined position. Description of the Drawings

[0017] Other measures for improving the invention are described in more detail below together with the description of the preferred exemplary embodiments. In the drawings: Figure 1 A partial longitudinal sectional view of a hand-held power tool with a bearing according to the invention is shown; Figure 2A perspective view of a part of the inner housing having a bearing according to an exemplary embodiment of the present invention is shown; Figure 3 a shows a view of a slider according to an exemplary embodiment of the present invention; Figure 3 b shows according to Figure 3 a perspective view of the slider of a; Figure 4 A cross-sectional view through a region of the elastic ring in a state of being mounted on the inner housing is shown; Figure 5 a shows a side view of an elastic ring with a slider according to an exemplary embodiment of the present invention; Figure 5 b shows a perspective view of an elastic ring according to an exemplary embodiment of the present invention; and Figure 5 c shows an enlarged view of the inner side of the elastic ring in the region of the opening. Detailed Description

[0018] Figure 1 A longitudinal cross-sectional view of a hand-held power tool 1 having a bearing 4 according to the present invention is shown. The hand-held power tool 1 has a percussion mechanism 8 through which an axial percussion pulse can be transmitted to a percussion tool (not shown). The percussion mechanism 8 is arranged in an inner housing 12. The inner housing 12 is partially surrounded by an outer housing 16. A bearing 4 is arranged between the inner housing 12 and the outer housing 16, and the bearing 4 supports the axial movement of the inner housing 12 relative to the outer housing 16. The inner housing 12 is decoupled from the outer housing 16 by the bearing 4.

[0019] Figure 2 A perspective view of a part of the inner housing 12 having a bearing 4 according to an exemplary embodiment of the present invention is shown. The bearing 4 is constituted by an elastic ring 20 applied to the inner housing 12. A plurality of sliders 24 protruding radially beyond the elastic ring 20 are arranged on the elastic ring 20. In a state where the hand-held power tool 1 is assembled, the sliders 24 abut against the inner side of the outer housing 16. The axial sliding movement of the inner housing 12 relative to the outer housing 16 is ensured by the sliders 24.

[0020] Figure 3 a and Figure 3b shows a view of the slider 24 according to an exemplary embodiment of the present invention. The slider 24 consists of a base body 28 with a convex sliding surface 30. In the assembled state, the sliding surface 30 abuts against the inner side of the outer housing 16. The radius of the convex sliding surface 30 corresponds to the inner radius of the outer housing 16. The slider 24 has an extension 32 that extends from the base body 28 on the side facing away from the sliding surface 30. The stop lug 36 is arranged on the extension 32 in the region of the axial end, which interacts with the elastic ring 20 after assembly so that the slider 24 is held on the ring 20.

[0021] Figure 4 A cross-sectional view through the region of the elastic ring 20 in the state of being mounted on the inner housing 12 is shown. For clarity, the slider 24 is not shown in this figure. The elastic ring 20 has a cutout 40 that partially receives the base body 28 of the slider 24 in the radial height. Therefore, the cutout 40 has the same shape as the slider 24. In addition, the elastic ring 20 has an opening 44 into which the extension 32 of the slider 24 projects. The inner housing 12 has a recess 48 in the region below the cutout 40 and the opening 44, and the depth t A is configured such that the slider 24 is elastically held above the recess 48.

[0022] Figure 5 a shows a side view of the elastic ring 20 with the slider 24 according to an exemplary embodiment of the present invention. Contrary to Figure 2 the exemplary embodiment of the elastic ring 20, the elastic ring 20 in this figure has a different outer radius r a or inner radius r i . The elastic ring 20 is subdivided into a plurality of parts 52 along the circumference. The parts 52 are arranged corresponding to the sliders 24, where the sliders 24 are each arranged in the outer parts 52a. The inner parts 52b are provided between the outer parts 52a, and the inner radius r i of the outer parts 52a is greater than that of the inner parts 52b. The elastic ring 20 abuts against the inner housing 12 only through the inner parts 52b. The outer parts 52a are thus not on the inner housing 12, thereby improving the spring effect of the slider 24.

[0023] Figure 5 b shows a perspective view of the elastic ring 20 according to an exemplary embodiment of the present invention. For clarity, the slider 24 is not shown in this figure. This figure basically shows the features that have been shown in the previous figures. Figure 5 c shows an enlarged view of the inner side of the elastic ring 20 in the region of the opening 44. In this region, an elastic knob 64 is formed around the opening 44, and the slider 24 is fixed by this knob 64 during assembly.

[0024] List of reference numerals 1 Hand-held power tool 4 Bearing 8 Impact mechanism 12 Inner housing 16 Outer housing 20 Elastic ring 24 Slide block 28 Substrate 30 Sliding surface 32 Extension 36 Stop lug 40 Notch 44 Opening 48 Recess 52 Portion 52a Outer portion 52b Inner portion 64 Elastic knob t A Depth r a Outer radius r i Inner radius

Claims

1. A hand-held power tool (1) for at least partially axially impacting machining of a material, the hand-held power tool comprising an inner housing (12) and an outer housing (16), at least one impact mechanism (8) being arranged in the inner housing, the outer housing at least partially surrounding the inner housing (12), wherein, a bearing (4) is arranged between the inner housing (12) and the outer housing (16) so as to decouple the axial movement of the inner housing (12) relative to the outer housing (16), characterized in that the bearing (4) comprises an elastic ring (20) applied to the inner housing (12), in which ring (20), a plurality of sliders (24) are embedded on the outer circumferential surface, and the plurality of sliders are in sliding contact with the outer housing (16).

2. The hand-held power tool (1) according to claim 1, characterized in that the slider (24) is made of sintered material.

3. The hand-held power tool (1) according to claim 1, characterized in that the slider (24) is made of carbon fiber reinforced plastic.

4. The hand-held power tool (1) according to one of the preceding claims, characterized in that a retaining means (64) is arranged on the inner surface of the elastic ring (20), and the retaining means interacts with the slider (24) such that the slider (24) is retained in the notch (40) of the elastic ring (20).

5. The hand-held power tool (1) according to one of the preceding claims, characterized in that the elastic ring (20) forms radially offset portions (52), wherein the slider (24) abutting against the outer housing (16) is arranged in the radially outer portion (52a), and the radially inner portion (52b) abuts against the inner housing (12).

6. The hand-held power tool (1) according to one of the preceding claims, characterized in that a defined recess (48) is formed in the inner housing (12) in the region below the slider (24) such that the slider (24) is elastically retained between the inner housing (12) and the outer housing (16) by the elastic ring (20).

7. The hand-held power tool (1) according to claim 5 or 6, characterized in that the bearing (4) is arranged in the region of a side handle fastener.

8. The hand-held power tool (1) according to one of the preceding claims, characterized in that the elastic ring (20) is arranged on the inner housing (12) in a prestressed state.

9. The hand-held power tool (1) according to one of the preceding claims, characterized in that the hardness of the elastic material is 50 to 90 Shore A hardness.

10. The hand-held power tool (1) according to one of the preceding claims, characterized in that the elastic ring (20) is arranged in a recess of the inner housing (12).

Images