Impact tool

Abstract

The invention relates to an impact tool which comprises a shell, a motor, a power transmission mechanism, an impact mechanism and an anvil, and the power transmission mechanism comprises a gear bearing piece and a bearing supporting piece fixedly installed in the shell; wherein the gear bearing part comprises a front bearing plate, a rear bearing plate, a tail part and at least one rolling bearing, the tail part extends outwards from the rear bearing plate in the axial direction, the rolling bearing is arranged on the tail part in a sleeving mode and contained in the bearing supporting part, at least one isolation part is arranged between the gear bearing part and the bearing supporting part, and the isolation part is arranged between the gear bearing part and the bearing supporting part. The isolation piece is arranged to enable a gap to be reserved between the front end face of the rolling bearing and the rear side face of the rear bearing plate, and the isolation piece is used for buffering axial force borne by the rolling bearing and coming from the impact mechanism and / or the gear bearing piece. The impact tool is compact in structure, and the service life of the impact tool and the service life of parts of the impact tool are greatly prolonged.

Description

Technical Field

[0001] The present invention relates to a power tool, in particular to an impact tool comprising an impact mechanism. Background Art

[0002] Impact power tools, such as impact wrenches and impact drivers, are widely known. These tools typically include a drive motor, a power transmission mechanism, an impact mechanism, and an output shaft. The power transmission mechanism is typically a planetary gear reduction mechanism. Impact tools use this planetary gear reduction mechanism to reduce the rotation of the drive motor and transmit it to the main shaft. The main shaft's rotation is then transmitted to the output shaft, such as an anvil, via the hammer of the impact mechanism.

[0003] The impact mechanism is typically constructed as a rotary impact mechanism, converting the continuous output power of the drive motor into impact-like rotational momentum. Typically, the impact mechanism comprises a hammer coupled to a spindle guide mechanism. The hammer engages an anvil axially supported at the front end of the tool housing. The spindle and hammer are driven by a motor, converting spindle rotation into intermittent rotary striking force (impacts) from the hammer, which acts on the anvil, imparting rotation and impact to the anvil, thereby intermittently transmitting rotary impact force to the tool tip. The impact motion actually occurs in a direction tangential to the rotational motion. The rotary motion used to implement the rotary impact is coupled to the axial reciprocating motion via a guide mechanism, ultimately forcing the hammer to follow a predetermined path within the guide mechanism. The axially reciprocating hammer applies a rotary impact to the anvil. At another reversal point in the reciprocating motion, the hammer disengages from the anvil. At this point, the hammer, facing the spindle, may strike the spindle, exerting an axial force on the power transmission mechanism. When the power transmission mechanism is subjected to this axial impact load, it further transmits this axial force to the rolling bearings supporting the power transmission mechanism. Therefore, whenever the impact tool is working, the rolling bearing will bear the axial load from the impact mechanism, causing the rolling bearing to easily fail or be damaged.

[0004] In order to solve the problems existing in the prior art, there is an urgent need for an impact tool that can increase the service life of the rolling bearing and thus increase the service life of the tool. Summary of the Invention

[0005] The object of the present invention is to provide an impact tool which is simple in structure and strong and durable.

[0006] An impact tool comprises a housing; a motor, a power transmission mechanism, an impact mechanism, and an anvil are housed within the housing, wherein the power transmission mechanism comprises a main shaft extending axially along a working axis, a gear carrier, and a bearing support fixedly mounted within the housing; wherein the gear carrier comprises a front bearing plate and a rear bearing plate arranged opposite and fixedly connected, and a tail portion extending axially rearward from the rear bearing plate, and at least one set of rolling bearings sleeved on the tail portion and housed within the bearing support; wherein at least one axial spacer is provided between the gear carrier and the bearing support, the spacer being configured to leave a gap between the front end surface of the rolling bearing and the rear bearing plate. In the impact tool of the present invention, by providing a spacer between the gear carrier and the bearing support, the axial load generated by the reciprocating motion of the hammer of the impact mechanism is first transmitted to the spacer via the gear carrier, rather than to the rolling bearing. The spacer absorbs or cushions the axial impact force, thereby protecting the rolling bearing from damage, extending the service life of the rolling bearing, and thereby extending the service life of the impact tool.

[0007] According to one embodiment of the present invention, the bearing support is generally a hollow ring, with a front end including a gear portion with annular internal teeth. A support portion extending radially toward the center is disposed behind the gear portion. The support portion defines a bearing mounting hole for accommodating the rolling bearing. A rear end of the support portion also includes a rear cover portion that at least partially covers the rear end surface of the rolling bearing. This bearing support provides a simple and compact structure for the impact tool's gearbox and provides space for the placement of a spacer.

[0008] According to a preferred embodiment of the present invention, the support portion includes a first surface facing the rear bearing plate, the spacer is disposed between the rear bearing plate and the first surface, and the front end surface of the spacer is closer to the rear bearing plate than the front end surface of the rolling bearing. Thus, during the reciprocating motion of the hammer of the impact mechanism along the axis, the axial impact force applied by the hammer to the gear bearing is first transmitted to the spacer via the rear bearing plate, rather than to the rolling bearing, thereby preventing damage to the rolling bearing caused by long-term axial impact loads.

[0009] Preferably, the isolation member is an annular washer surrounding the outer ring of the rolling bearing. In this way, the isolation member protects the rolling bearing from axial impact in an extremely simple manner, thereby increasing the service life of the rolling bearing.

[0010] According to another preferred embodiment of the present invention, the radial end of the rear cover portion extends beyond the inner ring of the rolling bearing and at least partially overlaps with the radial projection of the tail portion. The isolator is disposed between the tail portion and the radial end of the rear cover portion, and the sum of the axial lengths of the isolator and the tail portion is greater than the axial length of the rolling bearing. More preferably, the isolator is an annular washer that abuts the inner ring of the rolling bearing. The isolator, disposed between the tail portion and the rear cover portion, not only absorbs or cushions axial impact loads from the impact mechanism but also facilitates assembly.

[0011] According to another preferred embodiment of the present invention, the front load plate includes an extension portion extending radially until at least partially overlaps with the gear portion. The spacer is disposed between the extension portion of the front load plate and the front end face of the gear portion, and the spacer is configured to push the front load plate away from the front end face of the gear portion. Because the rolling bearing is tightly mounted to the bearing support, the rolling bearing is fixed relative to the bearing support, and the front and rear load plates are also fixedly connected, when the spacer is able to push the front load plate away from the bearing support, the rear load plate will no longer exert an axial impact on the rolling bearing behind it.

[0012] According to one embodiment of the present invention, the isolation member is a metal member. Isolation members made of metal have better wear resistance.

[0013] Alternatively, the isolating member is an elastic member that is elastically deformable. In this way, the isolating member can not only buffer the axial impact force from the impact mechanism and / or the gear carrier, but also buffer the vibration generated during the movement of the impact mechanism through elastic deformation.

[0014] Alternatively, the isolating member is a spring, such as a disc spring or a coil spring. Equally, the isolating member configured as a spring can absorb axial forces, protecting the rolling bearing from damage, and can also alleviate the vibration that the impact mechanism produces.

[0015] According to another embodiment of the present invention, the front end face of the support portion is axially closer to the rear bearing plate than the front end face of the rolling bearing. This eliminates the need for additional spacers. Instead, the support portion's inherent structure provides a gap between the front end face of the rolling bearing and the rear side of the rear bearing plate. The front end face of the support portion absorbs axial impacts from the impact mechanism and / or gear carrier, protecting the rolling bearing from continuous axial impact forces, thereby increasing the bearing's service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The embodiments described herein can be better understood by reading the accompanying drawings in conjunction with the following detailed description. It is emphasized that the various components are not necessarily drawn to scale. In fact, for clarity of discussion, the dimensions may be arbitrarily increased or decreased. In the accompanying drawings, the same reference numerals refer to the same elements.

[0017] Figure 1 is a perspective view of an illustrative embodiment of an impact tool of the present invention;

[0018] Figure 2 is an exploded schematic diagram of the power transmission mechanism 3 of the present invention;

[0019] Figure 3 A cross-sectional view of a gear box portion of an impact tool according to an embodiment of the present invention;

[0020] Figure 4 is a cross-sectional view of a gear box portion of an impact tool according to another embodiment of the present invention;

[0021] Figure 5 is a cross-sectional view of a gear box portion of an impact tool according to yet another embodiment of the present invention;

[0022] Figure 6 is a sectional view of a gear box portion of an impact tool according to still another embodiment of the present invention. DETAILED DESCRIPTION

[0023] Below, we will refer to Figures 1 to 6 An impact tool according to an embodiment of the present invention is described.

[0024] like Figure 1 As shown, the impact tool 10 of the present invention includes a housing 1; within the housing 2 are disposed a motor 2, a power transmission mechanism 3, an impact mechanism 4, and an anvil 5. The motor has a motor shaft 20 extending axially into the power transmission mechanism 3. As is well known to those skilled in the art, the impact tool 10 further includes, for example, a power supply, a switch, a mode switching mechanism, and the like. These mechanisms, as well as the aforementioned impact mechanism, can be constructed and operated in conventional manners and are therefore not further described here.

[0025] According to an exemplary embodiment of the present invention, the power transmission mechanism 3 is a set of planetary gear reduction mechanisms. Preferably, the planetary gears of the planetary gear reduction mechanism are two-stage gears. As will be appreciated by those skilled in the art, the planetary gear reduction mechanism may also be configured with one or more stages depending on the desired gear reduction ratio.

[0026] refer to Figure 1 and Figure 2The power transmission mechanism 3 may include a sun gear 30, planetary gears 31, a gear carrier 33, and a bearing support 34 with an annular internal tooth 32. The sun gear 30 may be coupled to the motor shaft 20 of the motor 2 for rotation. The planetary gears 31 include a plurality of, preferably three, planetary gears. The sun gear 30 is located at the front end of the motor shaft 20, so that the sun gear 30 can be driven to rotate by the motor 2. The sun gear 30 is engaged with the planetary gears 31, and the planetary gears 31 are also engaged with the annular gear 32 and rotate within the annular internal tooth 32.

[0027] The gear carrier 33 includes two parallel and fixedly connected front bearing plates 331 and rear bearing plates 332, and the planetary gear is arranged between the front bearing plates 331 and the rear bearing plates 332. The front bearing plate 331 is connected to the main shaft 7. Preferably, the main shaft 7 and the front bearing plate 331 are integrally formed. The rear bearing plate 332 is roughly annular, and the inner hole of the annular ring is used to receive the motor shaft 20 of the motor. The gear carrier 33 also includes a tail portion 333, which extends axially outward from the inner hole of the annular ring of the rear bearing plate 332 and is arranged roughly parallel to the rotation axis. At least one set of rolling bearings 36 is sleeved on the outer circumferential surface of the tail portion 333. Preferably, the inner ring of the rolling bearing 36 and the outer circumferential surface of the tail portion 333 are clearance-fitted.

[0028] The bearing support 34 is generally a hollow ring. One end of the hollow ring includes a gear portion 340 with an annular internal toothing 32 on its inner circumference. This annular internal toothing 32 meshes with the teeth of the planetary gears 31. The bearing support 34 is fixedly connected to the housing 1 at its outer circumference via an O-ring spring, meaning that the bearing support 34 is stationary relative to the housing 1. Behind the gear portion 340, the bearing support 34 has a support portion 341 extending radially toward the center. This support portion 341 defines a mounting hole within the bearing support with an inner diameter smaller than that of the annular internal toothing 32. The rolling bearing 36 is received within the mounting hole formed by this support portion 341. Preferably, the rolling bearing 36 is tightly fitted into the mounting hole, meaning that the rolling bearing 36 is stationary relative to the support portion 341. The support portion 341 includes a first surface 343 extending generally radially and abutting the rear side of the rear bearing plate of the gear carrier 33. Preferably, a washer is provided between the rolling bearing 36 and the rear bearing plate 332. A rear cover portion 342 is further provided behind the support portion 341 to at least partially cover the rear end surface of the rolling bearing 36.

[0029] refer to Figures 3 to 5At least one spacer 35 is provided between the gear carrier 33 and the bearing support 34. This spacer 35 is designed to create a gap between the front end of the rolling bearing 36 and the rear side of the rear bearing plate 332, thereby buffering the axial force exerted on the rolling bearing 36 by the impact mechanism. The inner ring and tail portion 333 of the rolling bearing 36 have a clearance fit, while the outer ring of the rolling bearing 36 has a tight fit with the support portion 341 of the bearing support 34. The gear carrier 33 is slightly movable axially, while the bearing support 34 is stationary. Therefore, when the hammer of the impact mechanism 4 reciprocates axially, it exerts an axial force on the spindle 7. Because the main shaft 7 and gear carrier 33 are integral, the gear carrier 33 may move slightly axially under the action of this axial force, thereby causing the inner ring of the rolling bearing 36 to move slightly axially. However, the outer ring of the rolling bearing 36 is stationary. Therefore, if the front face of the rolling bearing is continuously subjected to axial impact, the inner ring or ball of the rolling bearing 36 may be easily damaged. However, the spacer 35 of the present invention is configured to leave a gap between the front face of the rolling bearing and the rear bearing plate, thereby preventing damage to the rolling bearing 36 caused by bearing impact.

[0030] Figure 3 The figure illustrates a preferred embodiment of the present invention, in which the spacer 35 is disposed between the rear side surface of the rear load plate 332 and the first surface 343 of the support portion 341 facing the rear load plate, and the front end surface of the spacer 35 is closer to the rear load plate 332 than the front end surface of the rolling bearing 36. In this embodiment, the axial length of the support portion 341 is shorter than the bearing length of the rolling bearing 36, but the sum of the axial lengths of the support portion 341 and the spacer 35 is greater than the axial length of the rolling bearing 36. Typically, the rear end surface of the rolling bearing 36 is substantially flush with the rear end of the support portion, although there is a gap between the rear end surface of the rolling bearing 36 and the rear cover portion 342. In short, the spacer 35 is disposed so that its front end surface is closer to the rear load plate 332 than the front end surface of the rolling bearing 36. In this way, during the reciprocating motion of the hammer of the impact mechanism 4 along the axis, the axial impact force applied by the hammer to the main shaft 7 and then transmitted to the gear carrier 33 is first transmitted to the front end surface of the isolation member 35 through the rear bearing plate 332, rather than to the front end surface of the rolling bearing 36, thereby avoiding damage to the rolling bearing 36 caused by long-term axial impact load.

[0031] The material and shape of the spacer 35 can be selected from a variety of options. For example, according to one embodiment of the present invention, the spacer 35 is a metal member, such as an aluminum washer. Metal spacers have better wear resistance and can consistently ensure that the front end of the spacer is closer to the rear load plate than the front end of the rolling bearing, even under long-term use. In other words, a gap is always maintained between the front end of the rolling bearing 36 and the rear load plate.

[0032] Alternatively, the isolation member 35 is an elastic member that can be elastically deformed, such as a rubber washer. In this way, the isolation member 35 can not only buffer the axial impact force from the impact mechanism and / or the gear carrier, but also buffer the vibration generated during the movement of the impact mechanism through elastic deformation.

[0033] According to a preferred embodiment of the present invention, spacer 35, whether made of metal or elastic material, can be constructed as an annular washer surrounding the outer ring of rolling bearing 36. This simplifies assembly while providing a more balanced buffering effect against axial forces. With its extremely simple structure, spacer 35 protects rolling bearing 36 from axial impacts, thereby extending its service life.

[0034] Further alternatively, the isolating member 35 is a spring, such as a disc spring or a coil spring. Similarly, the isolating member configured as a spring can absorb axial forces, protect the rolling bearing from being damaged, and can also alleviate the vibration that the impact mechanism 4 produces.

[0035] Figure 4 Another preferred embodiment of the present invention is illustrated. In this embodiment, the radial end of the rear cover portion 342 extends beyond the inner ring of the rolling bearing 36 and at least partially overlaps with the projection of the tail portion 333 along a radial plane. The spacer 35 is disposed between the tail portion 333 and the radial end of the rear cover portion. The sum of the axial lengths of the spacer 35 and the tail portion 333 is greater than the axial length of the rolling bearing 36. The placement of the spacer between the tail portion and the rear cover portion not only absorbs or cushions axial impact loads from the impact mechanism but also facilitates assembly.

[0036] Likewise, in this embodiment, the isolating member may be a metal member, an elastic member or a spring. Preferably, the isolating member is an annular washer that abuts against the inner ring of the rolling bearing.

[0037] Figure 5FIG2 illustrates another preferred embodiment of the present invention, in which the front bearing plate 331 includes an extension portion 334 extending radially until at least partially overlaps with the gear portion 340. The spacer 35 is disposed between the extension portion 334 of the front bearing plate 331 and the front end face of the gear portion 340, and the spacer 35 is configured to push the front bearing plate 331 away from the front end face of the gear portion 340. Because the rolling bearing is tightly mounted to the bearing support, the rolling bearing is fixed relative to the bearing support, and the front and rear bearing plates are also fixedly connected, when the spacer pushes the front bearing plate away from the bearing support, the rear bearing plate no longer exerts an axial impact on the rolling bearing behind it.

[0038] Figure 6 Another embodiment according to the present invention is illustrated. Unlike the aforementioned embodiment, the additional isolation member 35 is eliminated in this embodiment. Instead, the front end face of the support portion 341 is directly positioned axially closer to the rear support plate 332 than the front end face of the rolling bearing. For example, the axial length of the support portion 341 is greater than the axial length of the rolling bearing 36, and the rear end face of the rolling bearing 36 is substantially flush with the rear end face of the support portion 341. In this way, a simple structure is used to achieve that the front end face of the support portion 341 abuts the rear support plate 332, while a gap is left between the front end face of the rolling bearing 36 and the rear support plate 332. The front end face of the support portion 341 is used to absorb axial impacts from the impact mechanism 4 and / or the gear carrier 33, protecting the front end face of the rolling bearing 36 from continuous axial impact forces, thereby increasing the service life of the rolling bearing.

[0039] It is understandable that the solution of leaving a gap between the front end face of the rolling bearing and the rear side face of the rear bearing plate by the structural design of the bearing support is not limited to Figure 6 For example, a first protrusion extending axially forward until it abuts against the tail portion may be provided on the rear cover portion, or a second protrusion extending axially forward until it abuts against the extension of the front bearing plate may be provided on the front end face of the gear portion. In short, any solution that prevents the front end face of the rolling bearing from being continuously subjected to axial impact from the gear bearing is within the scope of the present invention.

[0040] As mentioned above, although the exemplary embodiments of the present invention have been described in the specification with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, and many other embodiments are possible. The scope of the present invention should be limited by the claims and their equivalents.

Claims

1. An impact tool, comprising a housing; a motor, a power transmission mechanism, an impact mechanism and an anvil are arranged in the housing, wherein the power transmission mechanism includes a main shaft extending axially along a working axis, a gear carrier and a bearing support fixedly installed in the housing; wherein the gear carrier includes a front carrier plate and a rear carrier plate arranged oppositely and fixedly connected, and a tail portion extending axially rearward from the rear carrier plate, at least one set of rolling bearings is sleeved on the tail portion and accommodated in the bearing support portion, characterized in that: At least one axial spacer is provided between the gear carrier and the bearing support, and the spacer is arranged so that a gap is left between the front end surface of the rolling bearing and the rear bearing plate.

2. The impact tool according to claim 1, wherein The bearing support is roughly a hollow ring, and its front end includes a gear portion with annular internal teeth, and a support portion extending radially toward the center is provided behind the gear portion. The support portion forms a bearing mounting hole for accommodating the rolling bearing, and the rear end of the support portion is also provided with a rear cover portion that at least partially covers the rear end surface of the rolling bearing.

3. The impact tool according to claim 2, wherein: The support portion includes a first surface facing the rear bearing plate, the spacer is disposed between the rear bearing plate and the first surface, and a front end surface of the spacer is closer to the rear bearing plate than a front end surface of the rolling bearing.

4. The impact tool according to claim 2, wherein: The radial end of the rear cover portion extends beyond the inner ring of the rolling bearing and at least partially overlaps with the radial projection of the tail portion. The isolation member is arranged between the tail portion and the radial end of the rear cover portion, and the sum of the axial length of the isolation member and the axial length of the tail portion is greater than the axial length of the rolling bearing.

5. The impact tool according to claim 2, wherein The front carrier plate includes an extension portion extending in the radial direction until at least a portion overlaps with the gear portion. The spacer is disposed between the extension portion of the front carrier plate and the front end surface of the gear portion, and the spacer is configured to push the front carrier plate away from the front end surface of the gear portion.

6. The impact tool according to any one of claims 1 to 5, characterized in that The isolating member is an elastic member that is elastically deformable.

7. The impact tool according to any one of claims 1 to 5, characterized in that The spacer is a metal washer.

8. The impact tool according to any one of claims 1 to 5, characterized in that The spacer is a spring.

9. An impact tool, comprising a housing; a motor, a power transmission mechanism, an impact mechanism and an anvil are arranged in the housing, wherein the power transmission mechanism includes a main shaft extending axially along a working axis, a gear carrier and a bearing support fixedly installed in the housing; wherein the gear carrier includes a front carrier plate and a rear carrier plate arranged oppositely and fixedly connected, and a tail portion extending axially rearward from the rear carrier plate, at least one set of rolling bearings is sleeved on the tail portion and accommodated in the bearing support portion, characterized in that A gap is left between the front end surface of the rolling bearing and the rear side surface of the rear bearing plate.

10. The impact tool according to claim 9, wherein The bearing support is roughly a hollow ring, and its front end includes a gear portion with annular internal teeth. A support portion extending radially toward the center is provided behind the gear portion. The support portion forms a bearing mounting hole for accommodating the rolling bearing, and the front end face of the support portion is axially closer to the rear bearing plate than the front end face of the rolling bearing.

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