Oil leakage prevention mechanism and electric hammer

Abstract

The utility model relates to an oil leakage prevention mechanism and an electric hammer, the oil leakage prevention mechanism is applied to electric tools, the electric tool includes motor, transmission shell, bevel gear and front bearing, and the outer ring of front bearing is tightly connected with transmission shell. The oil leakage prevention mechanism is arranged between front bearing and the rotor of motor, the oil leakage prevention mechanism includes framework sealing element, bearing pressing sleeve and sealing ring, bearing pressing sleeve is annular and is assembled with transmission shell, and the end face of bearing pressing sleeve abuts the end face of outer ring of front bearing, and the sealing ring elastically extrudes the cooperation surface of bearing pressing sleeve and transmission shell, the framework sealing element is installed in the inner ring of bearing pressing sleeve and is elastically sealed with the surface of output shaft. The oil leakage prevention mechanism is located between motor and front bearing, thereby preventing the oil leakage of front bearing from entering motor. The oil leakage prevention mechanism forms multiple sealing structures through the cooperation of multiple components, prolongs the sealing path and improves the sealing reliability.

Description

Technical Field

[0001] This utility model relates to the field of power tool technology, and in particular to an oil leakage prevention mechanism and an electric hammer. Background Technology

[0002] During the operation of power tools such as electric hammers and drills, the motor drives the gear transmission mechanism through the output shaft. To ensure smooth transmission and extend the service life of components, lubricating oil is usually filled inside the transmission housing to lubricate and cool the transmission components. The motor output shaft and the transmission housing are usually only supported and initially sealed by a front bearing, with the outer ring of the front bearing tightly fitted to the transmission housing.

[0003] With prolonged use of power tools, the sealing performance of the front bearing gradually declines. Lubricating oil in the transmission housing can easily leak into the motor through the clearances between the front bearing and the output shaft, as well as between the front bearing and the transmission housing. This leakage not only wastes lubricating grease but also contaminates the motor's rotor, stator, and other core components.

[0004] To prevent lubricating grease leakage, an oil-proof mechanism is installed inside the electric hammer to prevent lubricating grease moving within the gear cavity from leaking into the rotor or stator of the motor. For example, publication number CN217890887U discloses a semi-open electric hammer housing oil-proof structure. And publication number CN204913815U discloses a rotating shaft front bearing sealing structure.

[0005] However, the sealing structure described above uses an elastic element to seal the shaft, and does not block the area between the front bearing and the motor. When the electric hammer is working, grease will leak from the gap in the dust cover in the middle of the ball bearing, and then enter the rotor and stator of the motor, causing motor failure and affecting the service life of the power tool. Therefore, this technical problem needs to be improved. Utility Model Content

[0006] To overcome the problems existing in the related technologies, this utility model provides an oil leakage prevention mechanism and an electric hammer to solve the technical problem of lubricating grease leaking to the motor through the ball bearing, affecting the service life of the power tool.

[0007] According to a first aspect of the present invention, an oil leakage prevention mechanism is provided, applied to an electric tool. The electric tool includes a motor, a transmission housing, a bevel gear mounted on the output shaft of the motor, and a front bearing. The outer ring of the front bearing is tightly fitted to the transmission housing. The oil leakage prevention mechanism is disposed between the front bearing and the rotor of the motor. The oil leakage prevention mechanism includes a skeleton seal, a bearing sleeve, and a sealing ring. The bearing sleeve is annular and assembled with the transmission housing. The end face of the bearing sleeve abuts against the end face of the outer ring of the front bearing. The sealing ring elastically compresses and seals the mating surface of the bearing sleeve and the transmission housing. The skeleton seal is installed on the inner ring of the bearing sleeve and is elastically sealed to the surface of the output shaft.

[0008] In one embodiment, the transmission housing is provided with at least one mounting groove, and the sealing ring is installed in the mounting groove.

[0009] In one embodiment, the bearing sleeve is provided with an assembly groove, and the bearing sleeve is installed in the assembly groove.

[0010] In one embodiment, the skeleton seal includes an annular skeleton body and at least one sealing lip protruding from the inner ring of the skeleton body. The skeleton body is tightly fitted and seals the inner ring of the bearing sleeve, and the sealing lip elastically abuts against the surface of the output shaft.

[0011] In one embodiment, the sealing lip includes a main tongue body that partially protrudes from the inner ring of the skeleton body and a branch tongue body that obliquely protrudes from one side of the main tongue body, the branch tongue body facing the front bearing side.

[0012] In one embodiment, the wall thickness of the main tongue body is greater than the wall thickness of the branch tongue body.

[0013] In one embodiment, the outer peripheral wall of the skeleton body has a local annular recess forming multiple spaced oil-separating grooves.

[0014] In one embodiment, the transmission housing is equipped with a pressure plate, which pushes against the bearing sleeve to press against the outer ring of the front bearing.

[0015] In one embodiment, the bevel gear includes a bevel gear body and an extension tube protruding from one side of the bevel gear body, the front bearing is mounted on the extension tube, and the end of the extension tube extends toward the skeleton seal.

[0016] According to a second aspect of the present invention, an electric hammer is provided, including an electric hammer body and an oil leakage prevention mechanism as described above.

[0017] The technical solution provided by the embodiments of this utility model can include the following beneficial effects: The oil leakage prevention mechanism is located between the motor and the front bearing, thereby preventing grease leaking from the front bearing from entering the motor, solving the technical problem of grease leakage into the motor. The oil leakage prevention mechanism forms a multi-layer sealing structure through the coordinated cooperation of multiple components, extending the sealing path, improving sealing reliability, and effectively preventing lubricating oil leakage. The skeleton seal and sealing ring are positioned and sealed based on the bearing sleeve, which is convenient to install and has a good barrier effect, greatly improving the operational stability and service life of the power tool, and reducing the user's maintenance frequency and maintenance costs. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention.

[0019] Figure 1 This is a schematic diagram illustrating the structure of an oil leakage prevention mechanism disposed in the transmission housing according to an embodiment.

[0020] Figure 2 This is an exploded structural diagram of the oil leakage prevention mechanism and the transmission housing according to an embodiment.

[0021] Figure 3 This is a cross-sectional schematic diagram showing an oil leakage prevention mechanism disposed in the transmission housing according to an embodiment.

[0022] Figure 4 yes Figure 3 Enlarged diagram of point A in the middle.

[0023] Figure 5 This is a schematic diagram illustrating a skeleton seal according to one embodiment.

[0024] Figure 6 This is a schematic diagram of a power tool according to one embodiment.

[0025] In the figure, there is a transmission housing 10; a grease space 11; a front bearing 12; a mounting groove 13; a transmission hole 14; a gear transmission mechanism 20; a bevel gear 21; an extension tube 211; a bevel gear body 212; a motor 30; an output shaft 31; an oil leakage prevention mechanism 40; a bearing sleeve 41; a skeleton seal 42; a skeleton body 421; a sealing lip 422; a main tongue 4221; a support tongue 4222; an oil separator groove 423; a sealing ring 43; a pressure plate 44; and an electric hammer body 50. Detailed Implementation

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the present invention. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art.

[0027] like Figures 1 to 4 As shown, this utility model provides an oil leakage prevention mechanism 40, which is applied to power tools, including electric hammers, electric drills, etc. An electric hammer is used as an example for illustrative purposes. The power tool includes an electric hammer housing, an impact mechanism, a gear transmission mechanism 20, and a motor 30. The motor 30 and the gear transmission mechanism 20 are connected to drive the impact mechanism. The transmission housing 10 is part of the electric hammer housing and is used to install the oil leakage prevention mechanism 40, the gear transmission mechanism 20, and the outer ring of the front bearing 12. The bevel gear 21 is part of the gear transmission mechanism 20 and is used to connect the output shaft 31 of the motor 30. The front bearing 12 supports the output shaft 31 and the transmission housing 10 to maintain the smooth rotation of the output shaft 31. Preferably, the front bearing 12 is a ball bearing, and the outer ring of the front bearing 12 is tightly fitted to the transmission housing 10.

[0028] The gear transmission mechanism 20 is in a lubricating grease environment, referred to as the grease space 11 for ease of description. The front bearing 12 is located between the grease space 11 and the motor 30. Furthermore, an oil leakage prevention mechanism 40 is provided between the front bearing 12 and the rotor of the motor 30 to block the grease that leaks from the grease space 11 out of the front bearing 12, so as to prevent the grease from entering the rotor and stator of the motor 30.

[0029] Specifically, the oil leakage prevention mechanism 40 includes a skeleton seal 42, a bearing sleeve 41, and a sealing ring 43. The bearing sleeve 41 is a rigid annular structure. The bearing sleeve 41 is assembled and connected to the transmission housing 10. The two can be fitted with a clearance fit, which can meet the assembly accuracy requirements and achieve convenient assembly. The end face of the bearing sleeve 41 abuts against the outer ring end face of the front bearing 12 to accurately press and assemble the front bearing 12 into the transmission housing 10.

[0030] Furthermore, a pressure plate 44 is installed on the transmission housing 10, which pushes against the bearing sleeve 41 to press against the outer ring of the front bearing 12. The transmission housing 10 is provided with a transmission hole 14, which has a stepped hole structure. The front bearing 12 and the bearing sleeve 41 are installed in the transmission hole 14 in sequence. The pressure plate 44 is fixed to the transmission housing 10 and presses against the end of the bearing sleeve 41, so that the pressure plate 44 pushes against the bearing sleeve 41 to press against the outer ring of the front bearing 12, keeping the installation position of the front bearing 12 and the bearing sleeve 41 stable. Optionally, one end of the bearing sleeve 41 protrudes slightly from the opening of the transmission hole 14; or, part of the pressure plate 44 extends into the transmission hole 14 and abuts against the bearing sleeve 41.

[0031] The pressure plate 44, by pushing against the bearing sleeve 41, can ensure that the bearing sleeve 41 and the outer ring end face of the front bearing 12 always maintain a tight contact, avoiding gaps between them due to vibration. At the same time, it can also axially fix the bearing sleeve 41 and prevent the bearing sleeve 41 from shifting axially.

[0032] A sealing ring 43 is disposed at the mating surface of the bearing sleeve 41 and the transmission housing 10, so that an elastic seal can be achieved at the mating surface after the bearing sleeve 41 and the transmission housing 10 are assembled. Furthermore, a skeleton seal 42 is installed on the inner ring of the bearing sleeve 41 and is elastically sealed to the surface of the output shaft 31.

[0033] The sealing ring 43 between the bearing sleeve 41 and the transmission housing 10 achieves a seal on the radial mating surface, while the elastic seal between the skeleton seal 42 and the output shaft 31 achieves a seal on the rotating surface, thus preventing grease from entering the motor 30, providing a good barrier effect. The oil leakage prevention mechanism 40 effectively prevents lubricating oil leakage, avoiding lubricating oil waste and contamination and damage to the core components of the motor 30, significantly improving the operational stability and service life of the power tool, and reducing the user's maintenance frequency and costs.

[0034] In one embodiment, the sealing ring 43 is installed on the transmission housing 10. Specifically, the transmission housing 10 is provided with at least one mounting groove 13, and the sealing ring 43 is installed in the mounting groove 13. The mounting groove 13 is an annular groove structure, which can accommodate and position the sealing ring 43. The inner diameter of the sealing ring 43 extends beyond the opening of the mounting groove 13, so that it can fit against the outer peripheral wall of the bearing sleeve 41 after the bearing sleeve 41 is assembled, ensuring that the sealing ring 43 is always in the sealing position of the mating surface between the bearing sleeve 41 and the transmission housing 10, thereby improving the stability of the seal. Furthermore, the mounting groove 13 provides a stable installation position for the sealing ring 43, preventing the sealing ring 43 from shifting due to vibration during the operation of the power tool.

[0035] In another embodiment, the sealing ring 43 is installed on the bearing sleeve 41. Specifically, the bearing sleeve 41 is provided with an assembly groove, and the bearing sleeve 41 is installed in the assembly groove. The assembly groove is located on the outer peripheral wall of the bearing sleeve 41 and has an annular groove structure. The assembly groove accommodates the sealing ring 43, and the outer diameter of the sealing ring 43 is slightly larger than the outer diameter of the bearing sleeve 41, so that after the bearing sleeve 41 is assembled to the transmission housing 10, the sealing ring 43 and the transmission housing 10 are sealed together.

[0036] Optionally, the sealing ring 43 is made of nitrile rubber, which has good oil resistance and elasticity.

[0037] like Figures 2 to 5As shown, the skeleton seal 42 is used to seal the bearing sleeve 41 and the output shaft 31. The skeleton seal 42 includes an annular skeleton body 421 and at least one sealing lip 422 protruding from the inner ring of the skeleton body 421. The skeleton body 421 is tightly fitted and seals the inner ring of the bearing sleeve 41, while the sealing lip 422 elastically abuts against the surface of the output shaft 31. The skeleton body 421 and the inner ring of the bearing sleeve 41 are either tightly fitted or elastically compressed to assemble the skeleton body 421 and the bearing sleeve 41. Optionally, the skeleton body 421 includes a built-in rigid ring and an elastic ring covering the rigid ring. The rigid ring provides a stable shape, and the elastic ring elastically conforms to the inner ring of the bearing sleeve 41, forming an elastic sealing connection.

[0038] Preferably, multiple oil-separating grooves 423 are distributed in a ring at intervals on the outer peripheral wall of the frame body 421, and an approximate sealing rib structure is formed between adjacent oil-separating grooves 423. The multiple oil-separating grooves 423 can form a multi-layer labyrinth-like sealing structure between the mating surfaces of the frame body 421 and the bearing sleeve 41. Even if a small amount of lubricating oil seeps into the mating surface, the oil-separating grooves 423 can block and store the lubricating oil, preventing it from further leaking to the motor 30 side, thus forming an auxiliary sealing defense line. Optionally, the oil-separating grooves 423 can be configured as three, five, six, etc.

[0039] The sealing lip 422 is a protruding structure with elastic deformation. It partially protrudes from the inner ring of the skeleton body 421. The skeleton body 421 provides reliable structural support for the sealing lip 422, ensuring that it maintains elastic contact with the surface of the output shaft 31 at all times. One or more sealing lips 422 can form multiple sealing lines, extending the sealing path. Even if one sealing lip 422 experiences slight wear, the remaining sealing lips 422 can still maintain their sealing effect, significantly improving sealing reliability.

[0040] Furthermore, the sealing lip 422 includes a main tongue 4221 that partially protrudes from the inner ring of the skeleton body 421 and a support tongue 4222 that protrudes obliquely from one side of the main tongue 4221, with the support tongue 4222 facing the front bearing 12. The main tongue 4221, as the primary sealing structure, forms a tight fit with the surface of the output shaft 31, playing a primary sealing role. The support tongue 4222, facing the front bearing 12, can initially block and guide leaking lubricating grease, preventing it from entering the main tongue 4221, reducing the sealing pressure on the main tongue 4221, and extending its service life.

[0041] Furthermore, the wall thickness of the main tongue 4221 is greater than that of the support tongue 4222. The larger wall thickness of the main tongue 4221 enhances its structural strength and wear resistance, ensuring that it is less prone to deformation and wear during long-term use; the smaller wall thickness of the support tongue 4222 gives it better elastic deformation capability, enabling it to better adapt to the vibration and slight radial runout of the output shaft 31, and improve the sealing fit.

[0042] Therefore, the wall thickness difference design between the main tongue 4221 and the support tongue 4222 of the skeleton seal 42 takes into account both structural strength and elastic fit performance, and can adapt to the high-frequency vibration and high-temperature operating conditions of power tools, ensuring long-term stable sealing performance.

[0043] In one embodiment, the bevel gear 21 includes a bevel gear body 212 and an extension tube 211 protruding from one side of the bevel gear body 212. The extension tube 211 and the bevel gear body 212 form an approximately T-shaped structure, and the output shaft 31 passes through the extension tube 211 and the bevel gear body 212. The front bearing 12 is mounted on the extension tube 211 and spaced apart from the bevel gear body 212. This provides rotational support for the bevel gear 21 and increases the distance between the front bearing 12 and the skeleton seal 42 by extending the extension tube 211, thereby increasing the buffer area volume between the front bearing 12 and the skeleton seal 42. Simultaneously, the end of the extension tube 211 can block lubricating oil to a certain extent, reducing the amount of lubricating grease flowing directly to the skeleton seal 42 and reducing the sealing burden.

[0044] like Figure 1 , Figure 2 and Figure 6 As shown, the oil leakage prevention mechanism 40 disclosed in the above embodiments is applied to an electric hammer. The electric hammer includes an electric hammer body 50 and the oil leakage prevention mechanism 40. This oil leakage prevention mechanism 40, applied to the electric hammer, can effectively solve the problem of lubricating oil leaking from the transmission housing 10 to the motor 30 during the operation of the electric hammer, thereby improving the operational stability and service life of the electric hammer.

[0045] During operation, the lubricating oil in the lubrication space lubricates the transmission components such as the bevel gear 21. The sealing ring 43 seals the clearance between the bearing sleeve 41 and the transmission housing 10. The support tongue 4222 provides initial blocking for the lubricating oil, the main tongue 4221 prevents further leakage of lubricating grease, and the oil separator 423 provides secondary blocking for any small amount of lubricating grease that has seeped in. The combined effect of multiple seals effectively prevents lubricating oil from leaking into the motor 30, ensuring the long-term stable operation of the electric hammer.

[0046] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary technical means in the art that are not disclosed in this invention.

Claims

1. An oil leakage prevention mechanism applied to a power tool, the power tool comprising a motor, a transmission housing, a bevel gear mounted on the output shaft of the motor, and a front bearing, wherein the outer ring of the front bearing is tightly fitted to the transmission housing, characterized in that, The oil leakage prevention mechanism is located between the front bearing and the rotor of the motor. The oil leakage prevention mechanism includes a skeleton seal, a bearing sleeve and a sealing ring. The bearing sleeve is annular and is assembled and connected to the transmission housing. The end face of the bearing sleeve abuts against the outer ring end face of the front bearing. The sealing ring elastically compresses and seals the mating surface of the bearing sleeve and the transmission housing. The skeleton seal is installed on the inner ring of the bearing sleeve and elastically seals the surface of the output shaft. The skeleton seal includes an annular skeleton body and at least one sealing lip protruding from the inner ring of the skeleton body. The skeleton body is tightly fitted and seals the inner ring of the bearing sleeve, and the sealing lip elastically abuts against and conforms to the surface of the output shaft. The sealing lip includes a main tongue body that partially protrudes from the inner ring of the skeleton body and a support tongue body that obliquely protrudes from one side of the main tongue body, with the support tongue body facing the front bearing side.

2. The oil leakage prevention mechanism according to claim 1, characterized in that, The transmission housing is provided with at least one mounting groove, and the sealing ring is installed in the mounting groove.

3. The oil leakage prevention mechanism according to claim 1, characterized in that, The bearing sleeve is provided with an assembly groove, and the bearing sleeve is installed in the assembly groove.

4. The oil leakage prevention mechanism according to claim 1, characterized in that, The wall thickness of the main tongue body is greater than the wall thickness of the branch tongue body.

5. The oil leakage prevention mechanism according to claim 1, characterized in that, The outer peripheral wall of the main skeleton has a local annular depression forming multiple oil-separating grooves.

6. The oil leakage prevention mechanism according to claim 1, characterized in that, The transmission housing is equipped with a pressure plate, which pushes against the bearing sleeve to press against the outer ring of the front bearing.

7. The oil leakage prevention mechanism according to claim 1, characterized in that, The bevel gear includes a bevel gear body and an extension tube protruding from one side of the bevel gear body. The front bearing is mounted on the extension tube, and the end of the extension tube extends toward the skeleton seal.

8. An electric hammer, characterized in that, It includes the electric hammer body and the oil leakage prevention mechanism as described in any one of claims 1 to 7.

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