Electric tool

Abstract

The utility model discloses an electric tool which comprises a shell. The gear box comprises a box shell, a cover body and a gear assembly; a power shaft hole is formed in the cover body, the shaft hole axially extends, the cover body further comprises a first positioning part axially abutted against the box shell and a second positioning part axially abutted against the shell, the box shell comprises a limiting structure matched with the first positioning part, the box shell and the shell are fixedly connected in the axial direction, and the first positioning part is axially abutted against and fixed to the limiting structure. The second positioning part is axially pressed against and fixed with the shell; the cover body further comprises a sealing abutting ring, the box shell comprises an annular sealing end edge opposite to the sealing abutting ring, and a first axial distance exists between the sealing end edge and the sealing abutting ring. The sealing ring is arranged between the sealing abutting ring and the sealing end edge, the axial thickness of the sealing ring is larger than the first axial distance, and the sealing end edge and the sealing abutting ring abut against the sealing ring in the axial direction. The sealing reliability and the service life of the gearbox sealing ring can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric tools, and in particular relates to an electric tool with a gear box sealing structure. Background Art

[0002] The gearbox is fixed by the box shell and the cover body, and the interior is used to accommodate the transmission gear and lubricating grease. In order to prevent the lubricating grease from leaking, a sealing structure needs to be set at the joint of the box shell and the cover body.

[0003] An existing gearbox sealing structure achieves interference sealing by interfering the inner cylindrical surface of the gearbox housing with the outer cylindrical surface of the cover body and assembling by press-fitting. However, due to the large vibration and high temperature rise during the operation of the gearbox, the interference fit is easy to loosen, which leads to oil leakage.

[0004] Another gearbox sealing structure uses a threaded connection between the inner cylindrical surface of the gearbox housing and the outer cylindrical surface of the cover, and the thread position is glued. This sealing treatment method has a good sealing effect, but the requirements for the thread processing position accuracy are extremely high, and the installation process is complicated, and the requirements for the glue coating process are high.

[0005] There is also a gearbox sealing structure, in which an O-ring is set between the inner cylindrical surface of the gearbox shell and the outer cylindrical surface of the cover body, and the O-ring is installed in the ring groove near the end of the inner cylindrical surface or the outer cylindrical surface. Due to the need to add a ring groove, the radial size of the gearbox increases by at least 2 times the wire diameter of the O-ring, which is not conducive to reducing the radial size of the whole machine. In addition, the vibration direction of the gearbox is the rotation direction, and there will be a relative displacement in the rotation direction between the shell and the cover body, which will cause the rear end face of the O-ring to wear after a long period of work, and then cause the seal to fail.

[0006] Therefore, it is necessary to improve the prior art to overcome the above defects in the prior art. Utility Model Content

[0007] Therefore, the utility model aims to solve the technical problem that the gear box sealing structure in the prior art is high in cost and unreliable.

[0008] In order to solve the above technical problems, the utility model provides an electric tool, comprising:

[0009] case;

[0010] The gear box comprises a box shell, a cover body and a gear assembly, wherein the inner space formed by the box shell and the cover body together constitutes a gear cavity, and the gear assembly is arranged in the gear cavity;

[0011] The cover body is provided with a power shaft hole, the power shaft hole extends axially, the cover body also includes a first positioning portion axially abutting against the box shell and a second positioning portion axially abutting against the shell, the box shell includes a limiting structure matched with the first positioning portion, the box shell and the shell are axially fixedly connected, the first positioning portion is axially pressed and fixed against the limiting structure, and the second positioning portion is axially pressed and fixed against the shell;

[0012] The cover body further comprises a sealing abutment ring, the box shell comprises an annular sealing end edge opposite to the sealing abutment ring, and a first axial distance exists between the sealing end edge and the sealing abutment ring;

[0013] The sealing ring is arranged between the sealing abutment ring and the sealing end edge, the axial thickness of the sealing ring is greater than the first axial distance, and the sealing end edge and the sealing abutment ring press the sealing ring axially.

[0014] In one embodiment, in the radial direction, the outer circumferential surface of the sealing ring is located radially inside the outer circumferential surfaces of the sealing abutment ring and the sealing end edge, or the outer circumferential surface of the sealing ring is flush with the outer circumferential surface of the sealing abutment ring and / or the sealing end edge.

[0015] In one embodiment, an annular groove is provided on the outer peripheral surface of the cover body, the side wall of the annular groove away from the sealing end edge is formed by the sealing abutment ring, and the radial inner edge of the sealing ring is embedded in the annular groove.

[0016] In one embodiment, the diameter of the circular ring formed by the bottom surface of the annular groove is larger than the inner diameter of the sealing ring, and the radial inner edge of the sealing ring is in interference fit with the bottom surface of the annular groove.

[0017] In one embodiment, the limiting structure includes a plurality of groove structures arranged on the inner circumferential surface of the box shell, and the first positioning portion includes a plurality of protrusion structures arranged on the outer circumferential surface of the cover body, and the protrusion structures are docked and embedded with the groove structures one by one along the axial direction.

[0018] In one embodiment, the protrusion structure and the groove structure are arranged in pairs, at least one pair of the protrusion structure and the groove structure have a first embedded matching structure that matches each other, and at least another pair of the protrusion structure and the groove structure have a second embedded matching structure that matches each other, and the first embedded matching structure and the second embedded matching structure are different.

[0019] In one embodiment, the gear assembly includes an inner gear ring, and the gear box includes a gasket for axially pressing the inner gear ring, the inner gear ring is arranged in the cover body, one side of the gasket is pressed against the end face of the inner gear ring and the first positioning portion, and the other opposite side of the gasket is pressed against the step surface of the groove structure, and when the box shell and the cover body are axially pressed and fixed, the gasket is pressed between the first positioning portion and the limiting structure.

[0020] In one embodiment, the shell includes a supporting portion that is abutted against the second positioning portion, the supporting portion and the second positioning portion are both annular and coaxially arranged, and the planes opposite to the supporting portion and the second positioning portion are abutted against each other.

[0021] In one embodiment, the sealing abutment ring is formed by an annular portion of the second positioning portion radially protruding beyond the first positioning portion.

[0022] In one embodiment, the electric tool is used to drive a working head to rotate or swing.

[0023] The technical solution provided by the utility model has the following advantages:

[0024] In the electric tool provided by the utility model, the sealing ring of the gear box is arranged between the sealing abutment ring of the cover body and the sealing end edge of the box shell, the axial thickness of the sealing ring is greater than the first axial distance between the sealing abutment ring and the sealing end edge of the box shell, and the sealing end edge and the sealing abutment ring press the sealing ring in the axial direction. In this way, the sealing ring is pressed axially to form a seal, but will not be over-pressed, which can ensure the life of the sealing ring and the reliability of the seal. Moreover, the sealing force of pressing the sealing ring is axial, which can suppress the wear of the sealing ring caused by the radial vibration of the gear box, and further ensure the reliability and life of the sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of the three-dimensional structure of the electric tool provided by the embodiment of the utility model;

[0027] Figure 2 for Figure 1 A schematic cross-sectional view of the electric tool shown;

[0028] Figure 3 for Figure 2An enlarged schematic diagram of the s region of the cross-sectional structural schematic diagram shown;

[0029] Figure 4 A schematic diagram of partial structural decomposition of a gear box provided in one embodiment of the utility model;

[0030] Figure 5 for Figure 4 A schematic diagram of the three-dimensional structure of the gear box housing shown in another angle;

[0031] Figure 6 The present invention is a cross-sectional structural diagram of the gear box cover, gasket and inner gear ring in cooperation with each other in one embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments. The utility model will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be noted that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0034] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0035] Figure 1 is a schematic diagram of the three-dimensional structure of the electric tool provided in this embodiment, Figure 2 for Figure 1 The cross-sectional structure diagram of the power tool shown in Figure 1 and Figure 2 As shown, this embodiment provides an electric tool 100, which includes a housing 10, a gear box 20, a motor 60, and an output shaft 50 for driving a working head to operate and perform a work task. The motor 60 and the gear box 20 are both arranged in the housing 10, the power input side of the gear box 20 is connected to the motor 60, the power output side of the gear box 20 is connected to the output shaft 50, and the other end of the output shaft 50 extends out of the housing 10 to connect to the working head. Based on the above transmission connection, the motor 60 drives the output shaft 50 through the gear box 20, thereby driving the working head to perform a work task.

[0036] The power tool 100 further includes a handle 30 for holding and a trigger 40 disposed on the handle, wherein the handle 30 is connected to or integrally formed with the housing 10. The trigger 40 is disposed at one end of the handle 30 close to the housing 10, and the user can trigger the trigger 40 to operate the power tool when grasping the handle 30. Therefore, the power tool provided in this embodiment can also be referred to as a handheld power tool.

[0037] In a specific implementation scenario, the power tool 100 further includes a battery pack interface disposed on the housing 10 for connecting a battery pack to achieve wireless operation. Therefore, the power tool 100 can also be referred to as a cordless power tool.

[0038] In a specific embodiment, there can be multiple types of electric tools. Depending on the different ways in which the working head moves, the electric tool 100 can be an oscillating electric tool or a rotating electric tool. When the electric tool 100 drives the working head to oscillate, the corresponding electric tool is an oscillating tool, such as an oscillating machine. When the electric tool 100 drives the working head to rotate, the corresponding electric tool is a rotating tool, such as an electric wrench or an electric drill. The utility model does not limit the specific type of the electric tool.

[0039] Gear box 20 is used for power transmission. Figure 2 and Figure 3 As shown, the gearbox 20 includes a housing 21, a cover 22 and a gear assembly 23. The internal space formed by the housing 21 and the cover 22 constitutes a gear chamber 28, and the gear assembly 23 is arranged in the gear chamber 28. The cover 22 is close to the power input side and is connected to the power shaft of the motor 60, and the housing 21 is close to the power output side and is connected to the output shaft 50. The active end of the gear assembly 23 is driven by the power shaft of the motor 60, and the driven end drives the output shaft 50. Through the gear assembly 23, the rotational power of the motor 60 can be converted into the power form of the output shaft 50 driving the working head. Usually, the gear assembly 23 is used for speed reduction, and the gearbox 20 is also called a speed reduction gearbox. According to the requirements of the movement mode of the working head of the power tool, a corresponding transmission mechanism can also be arranged between the gear assembly 23 and the output shaft 50.

[0040] The cover 22 is limitedly abutted against the housing 10, and the cover 22 is sandwiched between the housing 10 and the box shell 21. In the axial direction, the box shell 21 is tightly connected to the housing 10. Since the tightening force is in the axial direction, the cover 22 is axially clamped between the box shell 21 and the housing 10, so that the box shell 21 and the cover 22 are axially pressed at the front side of the cover 22 (the side close to the output shaft), so that the gear box 20 is sealed at the front side of the cover 22.

[0041] Specifically, the housing 10 and the box shell 21 are axially fastened and connected by bolts. Figure 1 and Figure 4, a fixing seat 11 is provided on the shell 10, and a fixing hole 210 is provided on the box shell 21. The fixing holes 210 are arranged in a one-to-one correspondence with the fixing seat 11, and the bolts pass through the fixing holes 210 and are tightened with the fixing seat 11. More specifically, the box shell 21 is sleeve-shaped, and the fixing holes 210 are arranged at intervals on the circumferential side wall of the box shell 21. The shell 10 has a ring portion docked with the box shell 21, and the fixing seat 11 is arranged in the circumference of the ring portion. The box shell 21 is docked with the ring portion of the shell 10, and the fixing holes 210 are aligned with the fixing seat 11 one by one, and the box shell 21 and the shell 10 are fixedly connected by bolts. In this embodiment, the box shell 21 constitutes a partial outer shell of the electric tool, and the cover body 22 is arranged in the shell 10, and is axially pressed between the box shell 21 and the shell 10.

[0042] Please also see Figure 3 and Figure 6 The cover body 22 is provided with a power shaft hole 220 for passing the power shaft, and the power shaft hole 220 extends axially, which is defined as the above-mentioned axial direction. The cover body 22 and the box shell 21 are pressed and fixed along the axial direction to form a seal at the pressing surface. The cover body 22 includes a first positioning portion 221 axially abutting against the box shell 21 and a second positioning portion 223 axially abutting against the shell 10. The first positioning portion 221 and the second positioning portion 223 are arranged in sequence along the axial direction, the first positioning portion 221 is close to the box shell 21, and the second positioning portion 223 is close to the shell 10. The box shell 21 includes a limiting structure that cooperates with the first positioning portion 221. After the box shell 21 and the shell 10 are fixedly connected along the axial direction, the first positioning portion 221 and the limiting structure are pressed and fixed axially. The housing 10 includes a supporting portion 12 that is abutted against the second positioning portion 223. The supporting portion 12 and the second positioning portion 223 are both annular and coaxially arranged. The planes opposite to the supporting portion 12 and the second positioning portion 223 are mutually abutted and matched, and the second positioning portion 223 is axially pressed and fixed to the housing 10. The supporting portion 12 is used to realize the axial positioning of the cover body 22 on the rear side (the side close to the power output). The supporting portion 12 and the second positioning portion 223 are both annular and coaxially arranged, and the end faces of the two are abutted, which can ensure that a larger abutting force surface is provided, the force is dispersed, and the reliable positioning of the cover body 22 is ensured.

[0043] That is to say, the axial sealing of the cover 22 and the box shell 21 is achieved by the axial fastening pressure of the box shell 21 and the housing 10, that is, after the box shell 21 and the housing 10 are firmly connected by bolts, the cover 22 and the box shell 21 are pressed in the axial direction to achieve the axial sealing. The axial sealing contact surface is a plane perpendicular to the axial direction.

[0044] The cover 22 and the housing 21 of the gearbox 20 are sealed in the axial direction, but the cover 22 and the housing 21 fit each other in the radial direction. There is a gap between the matching circumferential inner wall and circumferential outer wall of the cover 22 and the housing 21 in the radial direction to facilitate installation, so they also need to be sealed in the radial direction. In order to ensure the reliability and life of the radial seal, please refer to 3, 4 and Figure 5 , the cover body 22 also includes a sealing abutment ring 224, and the box shell 21 includes an annular sealing end edge 213 opposite to the sealing abutment ring 224. The annular sealing end edge 213 is formed at the annular end of the box shell 21. When the box shell 21 is axially and tightly connected to the housing 10, there is a first axial distance between the sealing end edge 213 and the sealing abutment ring 224. This distance can avoid the problem of being unable to install due to the size error of the cover body 22 and the box shell 21. The electric tool 100 also includes a sealing ring 24 arranged between the sealing abutment ring 224 and the sealing end edge 213. The axial thickness of the sealing ring 24 is greater than the first axial distance. When the box shell 21 is axially and tightly connected to the housing 10, the sealing end edge 213 and the sealing abutment ring 224 press the sealing ring 24 axially, so that the sealing ring 24 is compressed in the axial direction.

[0045] Due to the existence of the first axial distance, the sealing ring is compressed in the axial direction to form a seal, but it will not be over-pressed, which can ensure the life of the sealing ring and the reliability of the seal. In addition, the vibration of the gearbox is mainly radial, and the sealing ring is arranged between the two opposite end faces of the sealing abutment ring and the sealing end edge in the axial direction. The sealing force of the sealing ring is axial, which can suppress the wear of the sealing ring caused by the radial vibration of the gearbox, and ensure the reliability and life of the sealing ring.

[0046] It should be noted that although "the sealing ring is arranged between the two opposite end faces of the sealing abutment ring and the sealing end edge in the axial direction, and the sealing force of the sealing ring is in the axial direction", it does not mean that the radial sealing between the cover body 22 and the box shell 21 cannot be achieved. In fact, since this sealing ring is arranged between the sealing abutment ring 224 and the sealing end edge 213, and the opening formed between the sealing abutment ring 224 and the sealing end edge 213 due to the first axial distance is also the only outlet where oil leakage may occur in the radial direction, the sealing ring is arranged between the sealing abutment ring 224 and the sealing end edge 213, which not only achieves radial sealing, but also reduces the wear of the sealing ring caused by radial vibration. The reason is: if the sealing ring is directly arranged between the circumferential inner wall and the circumferential outer wall of the cover body and the box shell in the radial direction, during the operation of the electric tool, the sealing ring is frequently compressed and released under the radial vibration of the cover body and the box shell, and the sealing ring is very easy to wear and the seal is very easy to fail.

[0047] In order to reduce the size of the gearbox, the sealing ring 24 is provided without increasing the radial size of the gearbox 20. In one embodiment, please refer to Figure 3, the outer circumferences of the sealing abutment ring 224 and the sealing end edge 213 are flush, the outer circumference of the sealing ring 24 is flush with the outer circumferences of the sealing abutment ring 224 and the sealing end edge 213, or the outer circumference of the sealing ring 24 is located radially inward of the outer circumferences of the sealing abutment ring 224 and the sealing end edge 213, and the sealing ring 24 does not exceed the outer circumferences of the sealing abutment ring 224 and the sealing end edge 213. In another embodiment, the outer circumferences of the sealing abutment ring 224 and the sealing end edge 213 are not flush, and the outer circumference of the sealing ring 24 is flush with the outer circumference of one of the sealing abutment ring 224 and the sealing end edge 213; or, in the radial direction, the outer circumference of the sealing ring 24 is located radially inward of the outer circumferences of both or one of the sealing abutment ring 224 and the sealing end edge 213. The outer circumference of the sealing ring 24 does not exceed the outer circumference of the sealing abutment ring 224 or the sealing end edge 213, so that the radial size of the gearbox can be kept small.

[0048] In order to ensure the sealing effect of the sealing ring, in one embodiment, see Figure 3 and Figure 6 As shown, an annular groove 225 is provided on the outer peripheral surface of the cover body 22, and a sealing abutting ring 224 constitutes a side wall of the annular groove 225. The sealing abutting ring 224 is located on the side of the annular groove 225 away from the sealing end edge 213, and the sealing abutting ring 224 exceeds the other side wall of the annular groove 225 in the radial direction, and the radial inner edge of the sealing ring 24 is embedded in the annular groove 225. The two side surfaces of the sealing ring 24 opposite to each other in the axial direction, one of which abuts against the sealing abutting ring 224, and the other abuts against the other side wall of the annular groove 225 and the sealing end edge 213, the sealing ring 24 is compressed to achieve sealing at the joint between the box shell 21 and the cover body 22. Since the sealing ring 24 is embedded in the annular groove 225, the axial position of the sealing ring 24 can be fixed to ensure the sealing reliability.

[0049] The bottom surface of the annular groove 225 (also called the groove bottom of the annular groove 225) is roughly annular and coaxial with the power shaft hole 220. In order to suppress the movement of the sealing ring and ensure reliable positioning, the diameter of the ring formed by the bottom surface of the annular groove 225 is larger than the inner diameter of the sealing ring 24, and the radial inner edge of the sealing ring 24 is interference fit with the bottom surface 225 of the annular groove 225. The sealing ring is tightly sleeved on the annular groove, forming a seal with the bottom surface of the annular groove, and also suppressing the movement of the sealing ring, thereby improving the sealing effect.

[0050] In order to suppress the axial dimension of the gearbox, in the specific embodiment, see Figure 3 and Figure 6, the sealing abutment ring 224 is formed by the annular portion of the second positioning portion 223 that radially protrudes from the first positioning portion 221. That is to say, the sealing abutment ring 224 is formed in the second positioning portion 223 and is formed by the outer ring portion of the second positioning portion 223. Therefore, the sealing abutment ring utilizes the structure of the existing second positioning portion and does not increase the axial size of the gearbox. Specifically, the second positioning portion 223 is annular as a whole, and has an abutment surface facing the abutment portion 12. The abutment surface is perpendicular to the axial direction and extends to the same side surface of the sealing abutment ring 224. The abutment surface contacts the abutment portion 12 to achieve axial limiting of the cover body 22. The side of the sealing abutment ring 224 close to the abutment portion 12 is also pressed and matched with the abutment portion 12, which can provide a larger abutment contact surface, disperse the force, and ensure positioning reliability.

[0051] The axial pressing force of the axial fastening of the gear box 20 and the housing 10 is partially transferred to between the limiting structure and the first positioning portion 221 to achieve axial sealing between the housing 21 and the cover 22. For details, please refer to Figure 4 and Figure 5 The limiting structure includes a plurality of groove structures 212 disposed on the inner circumferential surface of the box shell 21, and the first positioning portion 221 includes a plurality of protrusion structures disposed on the outer circumferential surface of the cover body 22. The side of the groove structure 212 close to the sealing end edge 213 has no side wall and has an opening. The groove structure 212 extends in the axial direction, and the protrusion structure and the groove structure 212 are connected and embedded one by one from the opening of the groove structure 212 in the axial direction. The side wall of the groove structure 212 opposite to the opening is a step surface, and the end edge of the protrusion structure is used to press against the step surface in the axial direction.

[0052] The docking direction of the cover body 22 and the box shell 21 is not arbitrary. In order to avoid assembly errors, in one embodiment, the protrusion structure and the groove structure 212 are arranged in pairs, at least one pair of the protrusion structure and the groove structure 212 have a first embedded matching structure that matches each other, and at least another pair of the protrusion structure and the groove structure 212 have a second embedded matching structure that matches each other. The first embedded matching structure and the second embedded matching structure are different, so that the protrusion structure with the first embedded matching structure cannot be matched with the groove structure 212 with the second embedded matching structure, which can avoid assembly errors and achieve fool-proofing.

[0053] In a specific embodiment, the gear assembly 23 is a planetary gear assembly, see Figure 4 and Figure 6The gear assembly 23 includes an inner gear ring 231 and a plurality of planetary gears (not shown) disposed in the inner gear ring 231 and meshing with the inner gear ring 231. The inner gear ring 23 is assembled in the cover body 22, and the outer circumference of the inner gear ring 23 is in close contact with the inner circumference of the cover body 22. In order to prevent the inner gear ring 23 from shifting, the gear box 20 includes a gasket 25 for axially pressing the inner gear ring 23. One side of the gasket 25 abuts against the end surface of the inner gear ring 231 and the first positioning portion 221, and the other side of the gasket 25 opposite to the step surface of the groove structure 212. When the box shell 21 and the cover body 22 are axially pressed and fixed, the gasket 25 is pressed between the first positioning portion 221 and the groove structure 212.

[0054] Since one end face of the inner gear ring 23 is restrained against the cover body 22 and the other end face is restrained against the gasket 25, when the gasket 25 is pressed between the first positioning portion 221 and the groove structure 212 due to the axial locking force, the gasket 25 presses the inner gear ring 231 to position the inner gear ring 231 in the cover body 22, which not only realizes the positioning of the inner gear ring 231, but also shares the axial pressing force, thereby reducing the damage of the axial pressing force to the sealing ring.

[0055] Specifically, the gasket 25 includes a protrusion that matches the end surface of the first positioning portion 221. Since the protrusion structure and the groove structure have first and second embedded matching structures that match each other, the protrusion includes a first protrusion 251 corresponding to the first embedded matching structure and a second protrusion 252 corresponding to the second embedded matching structure. The first protrusion 251 and the second protrusion 252 have different shapes, so that it is easy to determine the assembly angle of the gasket 25.

[0056] In summary, in the electric tool provided in this embodiment, the sealing ring of the gear box is arranged between the sealing abutment ring of the cover body and the sealing end edge of the box shell, the axial thickness of the sealing ring is greater than the first axial distance between the sealing abutment ring and the sealing end edge of the box shell, and the sealing end edge and the sealing abutment ring press the sealing ring axially. In this way, the sealing ring is pressed axially to form a seal, but it will not be over-pressed, which can ensure the life of the sealing ring and the reliability of the seal. Moreover, the sealing force of the sealing ring is axial, which can suppress the wear of the sealing ring caused by the radial vibration of the gear box, and further ensure the reliability and life of the sealing ring.

[0057] Obviously, the above described embodiments are only a part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, ordinary technicians in this field can make other different forms of changes or modifications without creative work, which should fall within the scope of protection of the utility model.

Claims

1. An electric tool, characterized in that: include: case; The gear box comprises a box shell, a cover body and a gear assembly, wherein the inner space formed by the box shell and the cover body together constitutes a gear cavity, and the gear assembly is arranged in the gear cavity; The cover body is provided with a power shaft hole, the power shaft hole extends axially, the cover body also includes a first positioning portion axially abutting against the box shell and a second positioning portion axially abutting against the shell, the box shell includes a limiting structure matched with the first positioning portion, the box shell and the shell are axially fixedly connected, the first positioning portion is axially pressed and fixed against the limiting structure, and the second positioning portion is axially pressed and fixed against the shell; The cover body further comprises a sealing abutment ring, the box shell comprises an annular sealing end edge opposite to the sealing abutment ring, and a first axial distance exists between the sealing end edge and the sealing abutment ring; The sealing ring is arranged between the sealing abutment ring and the sealing end edge, the axial thickness of the sealing ring is greater than the first axial distance, and the sealing end edge and the sealing abutment ring press the sealing ring axially.

2. The electric tool according to claim 1, characterized in that: In the radial direction, the outer circumferential surface of the sealing ring is located radially inside the outer circumferential surfaces of the sealing abutment ring and the sealing end edge, or the outer circumferential surface of the sealing ring is flush with the outer circumferential surface of the sealing abutment ring and / or the sealing end edge.

3. The electric tool according to claim 1, characterized in that: An annular groove is arranged on the outer peripheral surface of the cover body, the side wall of the annular groove away from the sealing end edge is formed by the sealing abutment ring, and the radial inner edge of the sealing ring is embedded in the annular groove.

4. The electric tool according to claim 3, characterized in that: The diameter of the circular ring formed by the bottom surface of the annular groove is larger than the inner diameter of the sealing ring, and the radial inner edge of the sealing ring is in interference fit with the bottom surface of the annular groove.

5. The electric tool according to claim 1, characterized in that: The limiting structure includes a plurality of groove structures arranged on the inner circumferential surface of the box shell, and the first positioning portion includes a plurality of protrusion structures arranged on the outer circumferential surface of the cover body, and the protrusion structures are docked and embedded with the groove structures one by one along the axial direction.

6. The electric tool according to claim 5, characterized in that: The protrusion structure and the groove structure are arranged in pairs, at least one pair of the protrusion structure and the groove structure have a first embedded matching structure that matches each other, and at least another pair of the protrusion structure and the groove structure have a second embedded matching structure that matches each other, and the first embedded matching structure and the second embedded matching structure are different.

7. The electric tool according to claim 5, characterized in that: The gear assembly includes an inner gear ring, and the gear box includes a gasket for axially pressing the inner gear ring. The inner gear ring is arranged in the cover body, and one side of the gasket is pressed against the end face of the inner gear ring and the first positioning portion, and the other opposite side of the gasket is pressed against the step surface of the groove structure. When the box shell and the cover body are axially pressed and fixed, the gasket is pressed between the first positioning portion and the limiting structure.

8. The electric tool according to claim 1, characterized in that: The housing comprises a supporting portion that is abutted against the second positioning portion. The supporting portion and the second positioning portion are both annular and coaxially arranged. The planes of the supporting portion and the second positioning portion that are opposite to each other are abutted against each other.

9. The electric tool according to claim 1, characterized in that: The sealing abutment ring is formed by an annular portion of the second positioning portion that radially protrudes beyond the first positioning portion.

10. The electric tool according to claim 1, characterized in that: The electric tool is used to drive a working head to rotate or swing.

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