Hand-held power tool

Abstract

The invention relates to a hand-held power tool (1) for at least partially axially percussive material working, comprising an inner housing (12) in which at least one percussive mechanism (8) is located, and an outer housing (16) which at least partially surrounds the inner housing (12). A bearing (4) is arranged between the inner housing (12) and the outer housing (16) for decoupling an axial movement of the inner housing (12) in relation to the outer housing (16). The bearing (4) comprises a resilient ring (20) which is attached to the inner housing (12) and in which a plurality of sliding blocks (24) are embedded across an outer circumferential surface, which sliding blocks come into sliding contact with the outer housing (16).

Description

[0001] HAND MACHINE TOOL

[0002] DESCRIPTION

[0003] The present invention relates to a handheld power tool for at least partially axially impacting material processing, comprising an inner housing in which at least one impact mechanism is arranged, and an outer housing that at least partially surrounds the inner housing. To decouple an axial movement of the inner housing from the outer housing, a bearing is arranged between the inner housing and the outer housing.

[0004] The field of application of the invention extends primarily to handheld rotary hammers or chisel hammers equipped with an electric motor drive. Such electric hand tools generate a linearly alternating working movement via a mechanical percussion mechanism, i.e., a back-and-forth movement for impacting the tool, which in the case of a chisel hammer is designed as a chisel and in the case of a hammer drill as an impact drill for machining preferably mineral materials - such as stone, concrete, and the like. An electric hand tool capable of impact driving a tool usually exhibits complex vibration behavior due to interaction with the workpiece and the operator's hand-arm system, as well as the internal mass and stiffness distribution. This vibration behavior must be suppressed as far as possible.

[0005] State of the art

[0006] EP 0059 230 B1 discloses a self-lubricating elastic bearing for insertion between two relatively rotating elements. The bearing consists of an elastomer bearing bush with an inner surface with a low coefficient of friction, which interacts with the inner element or with an element rigidly connected to it, and with an outer surface arranged in a bearing housing. On the outer surface of the bearing bush or in said bearing housing, at least three projecting support surfaces are provided at an angular distribution to deform the inner friction surface of the bearing bush, ensuring its contact with the aforementioned inner element along the axial preload zones of the bearing bush, with the effect of centering and vibration damping between the two aforementioned elements.

[0007] The object underlying the invention is to provide a hand-held power tool with which vibrations can be reduced using simple technical means.

[0008] Disclosure of the invention

[0009] The object is achieved by a hand-held power tool for at least partially axially impacting material processing, according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims reflect advantageous developments of the invention.

[0010] The invention includes the technical teaching that the bearing comprises an elastic ring mounted on the inner housing, into which a plurality of sliding blocks are embedded on an outer circumferential surface, which sliding blocks come into sliding contact with the outer housing. Compression of the elastic ring can thus dampen radial vibrations and shocks between the inner housing and outer housing. In addition, the sliding blocks easily form a plain bearing, via which axial movement of the inner housing can be decoupled from the outer housing. The thus formed plain bearing can thus fulfill various functions. The elastic material is advantageously an elastomer.

[0011] According to a preferred embodiment, the sliding blocks are made of a sintered material. The sliding blocks are manufactured using a sintering process. This manufacturing process allows the sliding blocks to be manufactured in a simple technical manner. After sintering, such a sliding block still exhibits a certain porosity. This porosity allows lubricants to be stored in the pores and can be more effectively delivered by the sliding block, thus enabling improved lubrication of the bearing with a sliding block made of sintered material.

[0012] According to another preferred embodiment, the sliding blocks are made of a carbon-fiber-reinforced plastic. Components made of carbon-fiber-reinforced plastic are lighter than metal components. Such sliding blocks can be used to achieve a correspondingly low weight for a handheld power tool, thereby improving the handling of such a handheld power tool.

[0013] Preferably, retaining means are arranged on an inner surface of the elastic ring, which interact with the sliding blocks so that the sliding blocks are held in the recesses of the elastic ring. Retaining means are understood to be any configuration of the elastic ring or separate components that, after the sliding blocks have been installed, make disassembly of the sliding blocks more difficult. Such retaining means ensure, after the sliding blocks have been inserted, that the sliding blocks do not inadvertently detach from the elastic ring until the handheld power tool has been fully assembled. This simplifies assembly of the handheld power tool.

[0014] Alternatively or additionally, the sliding blocks have retaining means that interact with the elastic ring after the sliding blocks are mounted, so that the sliding blocks are held in the recess of the elastic ring. The retaining means are advantageously designed as locking lugs. Accordingly, retaining means on the sliding blocks can also simplify the assembly of the handheld power tool.

[0015] Advantageously, the elastic ring forms sections that are radially offset from one another, with the sliding blocks that rest on the outer housing being arranged in radially outer sections, whereas the radially inner sections rest on the inner housing. The elastic ring has a meandering shape. A section is understood to be an area of ​​the elastic ring that has the same outer or inner radius throughout. The radially inner sections have a smaller inner radius than the outer sections. Accordingly, the outer sections do not rest on the inner housing. The elastic ring provides a spring effect for the sliding block so that it rests resiliently on the outer housing. As a result, the inner housing is mounted on the outer housing by the bearing without play. The spring effect can also cushion radial vibrations or shocks.

[0016] Preferably, defined recesses are formed on the inner housing in the area below the sliding blocks, so that the sliding blocks are resiliently held between the inner housing and the outer housing via the elastic ring. The sliding blocks thus do not rest against the inner housing, allowing radial movement of the sliding blocks. Accordingly, the bearing can be mounted on the outer housing without play. The spring action of the sliding blocks thus allows radial vibrations or shocks to be decoupled. Depending on the selected geometry of the elastomer, recesses in the inner housing, and the elastomer material, the spring characteristic of the decoupling can be adjusted to the desired extent.

[0017] In an advantageous embodiment, the bearing is arranged in the area of ​​a side handle attachment. A side handle attachment is a device by which a user can fix a side handle, once it has been positioned, to the outer housing of the handheld power tool via a frictional connection. In this case, a retaining ring is often tightened on the outer housing. Such fixation often results in deformation of the outer housing. According to the prior art, such deformation would lead to uneven mounting in this area. The spring action of the sliding blocks according to the invention can compensate for such deformation, so that despite deformation of the outer housing, it can still be mounted evenly relative to the inner housing.

[0018] Advantageously, the elastic ring is arranged on the inner housing in a preloaded state. The inner radius of the elastic ring is slightly smaller than the outer radius of the inner housing. The elastic ring is therefore attached to the inner housing in a stretched state. This preloaded state ensures that a sufficient spring effect can be achieved directly with a radial deflection of the sliding blocks embedded in the elastic ring. The required spring force of the sliding blocks can also be adjusted by adjusting the degree of preload.

[0019] The elastic material preferably has a hardness of 70-90 Shore A. A material with such a hardness has good damping properties for dampening vibrations and shocks from a handheld power tool.

[0020] Preferably, the elastic ring is arranged in a recess in the inner housing. The inner housing thus has a recess that is at least as wide as the elastic ring. The elastic ring is thus held in the corresponding position by the recess and cannot slip. This ensures that the elastic ring is permanently held in the predetermined position.

[0021] Detailed description based on drawing

[0022] Further measures improving the invention are presented in more detail below, together with the description of a preferred embodiment. It shows:

[0023] Fig. 1 shows a partial longitudinal section of a hand-held power tool with a bearing according to the invention,

[0024] Fig. 2 perspective view of a part of the inner housing with an embodiment of the bearing according to the invention,

[0025] Fig. 3a View of a sliding block according to an embodiment of the invention,

[0026] Fig. 3b perspective view of the sliding block according to Figure 3a,

[0027] Fig. 4 Section through a portion of the elastic ring in a state mounted on the inner housing, Fig. 5a Side view of the elastic ring with sliding blocks according to an embodiment of the invention,

[0028] Fig. 5b perspective view of the elastic ring according to an embodiment of the invention, and

[0029] Fig. 5c enlarged view of an inner side of the elastic ring in the area of ​​the opening.

[0030] Figure 1 shows a longitudinal section through a handheld power tool 1 with a bearing 4 according to the invention. The handheld power tool 1 has a percussion mechanism 8, via which an axial impact 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. The bearing 4, which supports an axial movement of the inner housing 12 relative to the outer housing 16, is arranged between the inner housing 12 and the outer housing 16. The inner housing 12 is decoupled from the outer housing 16 via the bearing 4.

[0031] Figure 2 shows a perspective view of a portion of the inner housing 12 with an embodiment of the bearing 4 according to the invention. The bearing 4 is formed from an elastic ring 20, which is mounted on the inner housing 12. A plurality of sliding blocks 24 are arranged on the elastic ring 20 and project beyond the elastic ring 20 in a radial direction. When the handheld power tool 1 is assembled, the sliding blocks 24 rest against an inner side of the outer housing 16. The sliding blocks 24 ensure a sliding axial movement of the inner housing 12 relative to the outer housing 16.

[0032] Figures 3a and 3b show a view of a sliding block 24 according to an embodiment of the invention. The sliding block 24 is formed from a base body 28, which has a convex sliding surface 30. In an assembled state, the sliding surface 30 rests against an inner side of the outer housing 16. A radius of the convex sliding surface 30 corresponds to an inner radius of the outer housing 16. The sliding block 24 has an extension 32, which extends from the base body 28 on a side facing away from the sliding surface 30. Arranged on the extension 32 in a region of an axial end are locking lugs 36, which, after assembly, interact with the elastic ring 20, so that the sliding block 24 is held on the ring 20.

[0033] Figure 4 shows a section through a portion of the elastic ring 20 in a state mounted on the inner housing 12. For the sake of clarity, the sliding block 24 is not shown in this figure. The elastic ring 20 has a recess 40 which partially accommodates the base body 28 of the sliding block 24 at a radial height. Accordingly, the recess 40 has the same shape as the sliding block 24. The elastic ring 20 additionally has an opening 44 into which the extension 32 of the sliding block 24 projects. In the region below the recess 40 and the opening 44, the inner housing 12 has recesses 48 whose depth U is designed such that the sliding block 24 is resiliently held above the recess 48.

[0034] Figure 5a shows a side view of the elastic ring 20 with sliding blocks 24 according to an embodiment of the invention. Contrary to the embodiment of the elastic ring 20 in Figure 2, the elastic ring 20 in this figure has different outer and inner radii r. a, n. The elastic ring 20 is divided into a plurality of sections 52 along the circumference. The sections 52 are arranged corresponding to the sliding blocks 24, wherein the sliding blocks 24 are each arranged in outer sections 52a. Inner sections 52b are provided between the outer sections 52a, wherein the outer sections 52a have a larger inner radius n than the inner sections 52b. The elastic ring 20 only rests on the inner housing 12 via the inner sections 52b. The outer sections 52a therefore do not rest on the inner housing 12, so that a spring action of the sliding blocks 24 is improved. A perspective view of the elastic ring 20 according to an embodiment of the invention is shown in Figure 5b. This figure is shown without sliding blocks 24 for the sake of clarity.This figure essentially shows the features already shown in the previous figures. Figure 5c shows an enlarged view of the inside of the elastic ring 20 in the area of ​​the opening 44.

[0035] In this area, elastic knobs 64 are formed around the opening 44, by means of which the sliding block 24 is secured during assembly.

[0036] List of reference symbols

[0037] 1 hand tool

[0038] 4 camps

[0039] 8 percussion

[0040] 12 inner housing

[0041] 16 outer casings

[0042] 20 elastic ring

[0043] 24 sliding block

[0044] 28 base bodies

[0045] 30 sliding surface

[0046] 32 extension

[0047] 36 locking lugs

[0048] 40 recess

[0049] 44 Breakthrough

[0050] 48 recesses

[0051] Section 52

[0052] 52a outer section

[0053] 52b inner section

[0054] 64 elastic nubs

[0055] U Depth r a Outer radius n Inner radius

Claims

CLAIMS 1. Hand tool (1) for at least partially axially percussive material processing, comprising an inner housing (12) in which at least one percussion mechanism (8) is arranged, and an outer housing (16) which at least partially surrounds the inner housing (12), wherein a bearing (4) is arranged between the inner housing (12) and the outer housing (16) to decouple an axial movement of the inner housing (12) from the outer housing (16), characterized in that the bearing (4) comprises an elastic ring (20) applied to the inner housing (12), in which ring a plurality of sliding blocks (24) are embedded on an outer circumferential surface, which sliding blocks come into sliding contact with the outer housing (16).

2. Hand tool (1) according to claim 1, characterized in that the sliding blocks (24) are made of a sintered material.

3. Hand tool (1) according to claim 1, characterized in that the sliding blocks (24) are made of a carbon fiber reinforced plastic.

4. Hand tool (1) according to one of the preceding claims, characterized in that holding means (64) are arranged on an inner surface of the elastic ring (20), which holding means interact with the sliding blocks (24) so ​​that the sliding blocks (24) are held in recesses (40) of the elastic ring (20).

5. Hand tool (1) according to one of the preceding claims, characterized in that the elastic ring (20) forms sections (52) which are radially offset from one another, wherein the sliding blocks (24) resting on the outer housing (16) are arranged in radially outer sections (52a), whereas the radially inner sections (52b) rest on the inner housing (12).

6. Hand tool (1) according to one of the preceding claims, characterized in that defined recesses (48) are formed on the inner housing (12) in the region below the sliding blocks (24), so that the sliding blocks (24) are held resiliently between the inner housing (12) and the outer housing (16) via the elastic ring (20).

7. Hand tool (1) according to claim 5 or 6, characterized in that the bearing (4) is arranged in the region of a side handle attachment.

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

9. Hand tool (1) according to one of the preceding claims, characterized in that the elastic material has a hardness of 50-90 Shore A.

10. Hand 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