Shaft sealing structure

Abstract

The present application discloses a shaft sealing structure, comprising a housing having a through hole for a rotating shaft to pass through; further comprising: a first sealing bearing mounted on the rotating shaft and rotatably engaged with the rotating shaft, located on the inner end face side of the housing and axially limited within the through hole; a second sealing bearing located on the outer end face side of the housing and movable within the through hole in the axial direction of the through hole; and a first sealing assembly located between the first sealing bearing and the second sealing bearing, the first sealing assembly being an axially deformable elastic structure to accommodate the displacement of the second sealing bearing. The sealing structure of the present application ensures the sealing between the shaft and the housing mounting hole through multi-stage sealing, blocks the infiltration of external liquids, and can meet the sealing requirements of underwater operations; the flexible seal of the first sealing assembly can buffer the axial displacement caused by vibration during operation of the power tool.

Description

Technical Field

[0001] The present application relates to a sealing structure, and in particular to a shaft sealing structure for an electric tool. Background Art

[0002] Power tools are a type of power tools that are relatively common in production and life, such as electric hole drills, electric screwdrivers, electric wrenches, electric threading machines, etc. In common power tools, the power source and transmission mechanism are encapsulated in the outer shell, the working shaft head is installed through the outer shell, the transmission mechanism connects the power source and the working shaft head, the working shaft head is connected to the external working part such as a drill bit, screwdriver, wrench, etc., the power source transmits power to the working shaft head through the transmission mechanism, drives the working shaft head to rotate, and thus drives the external working part to perform the operation. The working shaft head and the mounting hole of the outer shell need to be sealed to prevent external dust and the like from entering the outer shell. The traditional shaft sealing structure can meet the barrier requirements for dust and the like in terrestrial use environments, but cannot meet the sealing requirements during underwater operations. Summary of the Invention

[0003] The present application provides a shaft sealing structure that enhances sealing reliability through multi-stage sealing and can be used to block external liquids for underwater operating equipment.

[0004] A shaft sealing structure for an electric tool includes a housing having a through hole for a rotating shaft to pass through, and is characterized in that it also includes:

[0005] a first sealed bearing, located on the inner end surface side of the housing and axially confined within the through hole;

[0006] a second sealed bearing, located on the outer end surface side of the housing and movable in the through hole in the axial direction of the through hole;

[0007] as well as

[0008] A first sealing component is located between the first sealed bearing and the second sealed bearing, and the first sealing component is an elastic structure that is deformable in the axial direction to adapt to the displacement of the second sealed bearing.

[0009] The sealing structure of the present application ensures the sealing between the shaft and the housing mounting hole through multi-stage sealing, blocks the infiltration of external liquid, and can meet the sealing requirements of underwater operations; the flexible seal of the first sealing component can buffer the axial displacement caused by vibration when the power tool is working.

[0010] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution. They are merely further supplements or optimizations. Under the premise that there are no technical or logical contradictions, each optional method can be combined separately for the above-mentioned overall solution, or multiple optional methods can be combined.

[0011] Optionally, a first step is provided in the through hole, and a shaft shoulder is provided on the rotating shaft and located on the inner side of the housing, and the first step and the shaft shoulder cooperate to limit the axial direction of the first sealed bearing in the through hole.

[0012] Optionally, it further comprises a second sealing assembly sleeved on the rotating shaft and rotatably engaged with the rotating shaft, wherein the second sealing assembly is located between the first sealing assembly and the second sealed bearing;

[0013] A second step is provided in the through hole for limiting the axial movement of the second sealing assembly toward the outer end surface of the housing;

[0014] The rotating shaft is provided with a shaft ring located on the outer side of the housing for limiting the displacement of the second sealed bearing.

[0015] Optionally, the first sealing component includes:

[0016] a first sealing ring, sleeved on the rotating shaft and with one end thereof abutting against the first sealing bearing;

[0017] a second sealing ring, sleeved on the rotating shaft and having one end abutting against the second sealing bearing or the second sealing assembly; the first sealing ring and the second sealing ring are abutted against each other at their facing ends, with a radial gap being left between the abutting point and the outer surface of the rotating shaft to form a cavity;

[0018] A spring is sleeved on the outer circumference of the first sealing ring, and one end of the spring abuts against the back surface of the abutting connection between the first sealing ring and the second sealing ring.

[0019] Optionally, one end of the first sealing ring has an axial protrusion and the other end has an annular flange radially outward; the axial protrusion abuts the first sealing bearing and the inner annular surface of the axial protrusion is tightly against the surface of the rotating shaft and rotates together; one side of the annular flange abuts the second sealing ring and the other side abuts the spring.

[0020] Optionally, the first sealing assembly further includes:

[0021] a first spring seat, which is sleeved outside the axial protrusion of the first sealing ring and has a step structure that cooperates with the axial protrusion to limit the axial position; the first spring seat has a radially outer ring edge, one side of the ring edge abuts the first sealing bearing and the other side abuts the spring;

[0022] The second spring seat is sleeved outside the first sealing ring and has a radially inward ring edge, one side of the ring edge abuts against the annular flange of the first sealing ring and the other side abuts against the spring.

[0023] Optionally, the second sealing ring has an axial protrusion at one end and an annular flange radially outward at the other end, the annular flange abuts against the first sealing ring, and the axial protrusion abuts against the second sealing bearing or the second sealing assembly;

[0024] A radial gap is provided between the inner ring surface of the second sealing ring and the surface of the rotating shaft, forming an axial channel, and the axial channel is communicated with the cavity.

[0025] Optionally, at least one of the two facing end surfaces of the first sealing ring and the second sealing ring has a concave structure centered on the corresponding axial hole, so as to form the cavity when the first sealing ring and the second sealing ring are abutted and connected;

[0026] The first sealing assembly further includes a first ring sleeve for packaging the first sealing ring, the second sealing ring and the spring into the first sealing assembly.

[0027] Optionally, one end where the first sealing ring and the second sealing ring are connected to each other is a flared structure centered at the axial hole.

[0028] Optionally, the second sealing assembly includes:

[0029] a third sealing ring, which is sleeved on the rotating shaft and has one end in contact with the second sealing ring, and an inner ring surface of the third sealing ring is in close contact with the surface of the rotating shaft and rotates in engagement;

[0030] The second ring sleeve is sleeved on the outside of the second sealing ring and abuts against the second step. The end of the second ring sleeve facing the outside of the shell has a ring edge that is radially inward and forms a radial gap with the outer surface of the rotating shaft. One side of the ring edge abuts the third sealing ring and the other side abuts the second sealed bearing.

[0031] Optionally, the second ring sleeve is an elastic member whose material is softer than that of the third sealing ring;

[0032] Preferably, the second ring sleeve is a rubber ring; the third sealing ring is a PTFE ring;

[0033] Preferably, the first sealing ring and the second sealing ring are both PTFE rings.

[0034] Compared with the prior art, this application has at least one of the following beneficial effects:

[0035] (1) The present application ensures the sealing between the shaft and the housing mounting hole through multi-stage sealing, which can meet the sealing requirements of underwater operations.

[0036] (2) The sealing assembly of the present application realizes flexible sealing in the axial direction and has a good shock-absorbing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a cross-sectional view of the shaft sealing structure of the present application;

[0038] Figure 2 This is an exploded view of the shaft seal structure of this application;

[0039] Figure 3 for Figure 1 a cross-sectional view of the middle shell portion;

[0040] Figure 4 Bit Figure 1 A partial enlarged view of the first sealing component.

[0041] The reference numerals shown in the figures are as follows:

[0042] 1-First sealed bearing 2-First spring seat 4-First sealing ring

[0043] 4-Second sealing ring 5-Spring 6-Second spring seat

[0044] 7-first ring sleeve 8-third sealing ring 9-second ring sleeve

[0045] 10-Second sealed bearing 11-Housing 12-Shaft collar

[0046] 13-rotating shaft 14-cavity 15-axial channel

[0047] 16-Shaft shoulder 17-First step 18-Second step

[0048] 19-Through hole DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0051] like Figures 1 to 3As shown, a shaft sealing structure is used for sealing the working shaft head of a handheld power tool, including a housing 11. The housing 11 has a through hole 19 for a rotating shaft 13 to pass through. The rotating shaft 13 and the housing 11 are connected via a sealed bearing located in the through hole. The sealed bearing is sleeved on the rotating shaft. The sealed bearing realizes the connection between the rotating shaft and the housing while also realizing the sealing between the rotating shaft and the through hole. The sealed bearing includes a first sealed bearing 1 and a second sealed bearing 10. The first sealed bearing and the second sealed bearing can both adopt double-sided sealed deep groove ball bearings, such as S6904Z bearings. The first sealed bearing 1 is located on the inner end face side of the housing 11, and the second sealed bearing 10 is located on the outer end face side of the housing 11. The first sealed bearing and the second sealed bearing respectively realize two seals. The first sealed shaft 1 is axially limited in the through hole, and the second sealed bearing 10 can move axially within a certain range to adapt to the tiny displacement caused by the vibration of the rotating shaft. A first sealing assembly is arranged between the first sealed bearing 1 and the second sealed bearing 10. The first sealing assembly is sleeved on the rotating shaft and rotates with the rotating shaft. The first sealing assembly is an axially deformable elastic part, and the axial deformation space of the first sealing assembly is to adapt to the axial displacement of the second sealed bearing 10.

[0052] As an implementation method for achieving axial limitation of the first sealed bearing, a first step 17 is provided in the through hole of the shell, and the part of the rotating shaft located on the inner side of the shell is provided with a shoulder 16. One of the two end faces of the first sealed bearing 1 abuts against the first step 17 and the other abuts against the shoulder 16. The first step in the through hole and the shoulder of the rotating shaft cooperate with each other to axially limit the first sealed bearing in the through hole, thereby limiting the axial movement of the first sealed bearing.

[0053] As an embodiment of the first sealing assembly, it includes a first sealing ring 3, a second sealing ring 4 and a spring 5. The first sealing ring 3 and the second sealing ring 4 are both mounted on the rotating shaft and arranged along the axial direction of the rotating shaft. The first sealing ring 3 and the second sealing ring 4 are abutted against each other. There is a radial gap between the abutting connection between the first sealing ring and the second sealing ring and the outer surface of the rotating shaft, and the radial gap forms a cavity 14; the spring 5 is installed on the first sealing ring 3, and one end of the spring abuts against the back side of the abutting connection between the first sealing ring and the second sealing ring.

[0054] As a specific structure of the first sealing ring, the first sealing ring 3 has an axial protrusion at one end and an annular flange radially outward at the other end. The axial protrusion 301 of the first sealing ring extends toward the first sealing bearing and abuts against the first sealing bearing; the second sealing ring 4 has an axial protrusion at one end and an annular flange radially outward at the other end, and the axial protrusion 401 of the second sealing ring extends toward the second sealing bearing. The first sealing ring and the second sealing ring are abutted and connected by their respective annular flanges (302 and 402). To facilitate the formation of the cavity, at least one of the two facing end faces of the first sealing ring 3 and the second sealing ring 4 has a concave structure centered on its corresponding axial hole. The concave structure on the first sealing ring is recessed toward the axial protrusion of the first sealing ring, and the concave structure on the second sealing ring is recessed toward the axial protrusion of the second sealing ring.

[0055] In a preferred embodiment, the facing end surfaces of the first and second sealing rings both have concave structures. As a specific embodiment of the concave structure, the connecting ends of the first and second sealing rings can each be configured as a flared structure centered on their respective axial holes. Furthermore, to facilitate installation, in a more preferred embodiment, the outer edge of the flared structure of the second sealing ring is slightly larger than the outer edge of the flared structure of the second sealing ring, allowing a portion of the first sealing ring to extend into the flared structure of the first sealing ring.

[0056] The inner ring surface of the axial protrusion of the first sealing ring is in close contact with the outer surface of the rotating shaft and can rotate relatively thereto. A radial gap is provided between the inner ring surface of the second sealing ring and the outer surface of the rotating shaft. The radial gap forms an axial channel 15 which is in communication with the cavity 14 .

[0057] To facilitate the installation of the spring, the first sealing assembly also includes a first spring seat 2 and a second spring seat 6. The spring 5 is installed on the first sealing ring 3 through the first spring seat and the second spring seat. The first spring seat 2 is a ring sleeve structure and is sleeved outside the axial protrusion of the first sealing ring 3. The first spring seat 2 has a sleeve connected to the first sealing ring and a radially outward ring edge. The ring edge 201 of the first spring seat is located at one end close to the first sealing bearing. The ring edge abuts the first sealing bearing on one side and the spring 5 on the other side. The first spring seat is sleeved on the axial protrusion of the first sealing ring through its sleeve. The sleeve and the axial protrusion of the first sealing ring 3 have a step structure that cooperates with each other to limit the axial position. One end of the spring is sleeved outside the first spring seat 2 and abuts against the ring edge 201 of the first spring seat. The second spring seat 6 is a ring-shaped structure, and one end close to the abutment connection between the first sealing ring and the second sealing ring has a radially inward ring edge. One side of the ring edge 601 of the second spring seat abuts the side surface of the annular flange of the first sealing ring and the other side abuts the spring. The other end of the spring 5 extends into the second spring seat 6 and abuts against the ring edge 601 of the second spring seat.

[0058] In a more preferred embodiment, the first sealing assembly further comprises a first ring sleeve 7, which is sleeved outside the annular flanges of the first sealing ring and the second sealing ring. The first ring sleeve has a radially inward ring edge at one end facing the second sealed bearing. The first ring sleeve is supported on the annular flange of the second sealing ring by the ring edge 701, encapsulating and connecting the various components of the first sealing assembly. The annular flange 302 of the first sealing ring, the annular flange 402 of the second sealing ring, the second spring seat 6 and part of the spring 5 are all encapsulated in the first ring sleeve 7.

[0059] The second sealing ring 4 is sleeved into the first ring sleeve 7, and the axial protrusion of the second sealing ring 4 extends out of the first ring sleeve 7. The first sealing ring 3 is pressed into the first ring sleeve 7 and abuts against the second sealing ring 4. The second spring seat 6 is pressed on the first sealing ring 3, and the spring 5 is sleeved on the first sealing ring 3 and abuts against the first spring seat 6. The first spring seat 2 is pressed on the axial protrusion of the first sealing ring 3, and the spring 5 is sleeved on the first sealing ring. The second spring seat 2 is sleeved on the first sealing ring and abuts against the spring. After the assembly is completed, the second sealing assembly is installed on the rotating shaft 13 as a whole.

[0060] To further enhance the sealing effect, a second sealing assembly is provided between the first sealing assembly and the second sealing bearing. The axial ends of the second sealing assembly abut against the first sealing assembly and the second sealing bearing, respectively. The second sealing assembly is mounted on the rotating shaft and rotatably engages with the rotating shaft. A second step 18 is provided within the through-hole of the housing. The portion of the end face of the second sealing assembly facing the outside of the housing abuts against this second step 18. The second step is used to limit the axial movement of the second sealing assembly toward the outer end face of the housing. A collar 12 is provided on the rotating shaft 13 and located outside the housing. The collar 12 limits the axial displacement of the second sealing bearing. A slight axial gap is provided between the collar 12 and the outer end face of the through-hole. This gap cooperates with the axial deformation of the first sealing assembly to accommodate the slight axial displacement of the second sealing bearing during operation of the rotating shaft. One embodiment of the collar may utilize a retaining spring.

[0061] As an embodiment of the second sealing assembly, the second sealing assembly includes a third sealing ring 8 and a second ring sleeve 9. The third sealing ring 8 is mounted on the rotating shaft 13. The inner ring surface of the third sealing ring is in close contact with the outer surface of the rotating shaft and can rotate relative to it. The second ring sleeve 9 is mounted outside the third sealing ring 8. As a specific embodiment of the second ring sleeve, the second ring sleeve has a radially inward ring edge 901 at one end near the second sealed bearing 10. The second ring sleeve is supported on the third sealing ring by the ring edge. One side of the ring edge abuts the end face of the third sealing ring and the other side abuts the end face of the second sealed bearing. The end face of the second ring sleeve near the second sealed bearing 10 also abuts the second step 18. A radial gap is provided between the ring edge of the second ring sleeve and the rotating shaft to ensure that the frictional resistance of the rotating shaft is reduced when the rotating shaft rotates under the effect of increasing the seal. The outer ring surface of the second ring sleeve is in close contact with the inner wall of the through hole.

[0062] The second ring sleeve is an elastic member made of a softer material than the third sealing ring. Preferably, the second ring sleeve is a rubber ring, and the third sealing ring is a PTFE ring. Preferably, both the first and second sealing rings are PTFE rings. PTFE has excellent axial lubrication, providing critical sealing and rotational lubrication during the tight fit between the PTFE ring and the rotating shaft.

[0063] In an embodiment without a second sealing component, the first sealing bearing, the first sealing component and the second sealing bearing of the assembled shaft sealing structure are abutted and connected in sequence along the axial direction of the rotating shaft; three levels of sealing are formed in sequence, and the axial displacement of the second sealing bearing caused by vibration is buffered by the axial deformation of the first sealing component.

[0064] In embodiments incorporating a second sealing assembly, the assembled shaft sealing structure comprises a first sealing bearing, first sealing assembly, second sealing assembly, and second sealing bearing, all abutting each other in sequence along the axial direction of the rotating shaft. This creates a four-stage seal, with the axial deformation of the first sealing assembly buffering axial displacement of the second sealing bearing caused by vibration. In this embodiment, the second sealing bearing 10 forms the first seal, the second sealing assembly forms the second seal, the first sealing assembly forms the third seal, and the first sealing bearing 1 forms the fourth seal. This multi-stage seal enhances the sealing and waterproofing performance between the rotating shaft and the housing. Axial displacement caused by vibration during operation of the rotating shaft is mitigated by the axial deformation of the first sealing assembly.

[0065] At the same time, the presence of the axial channel and cavity in the first sealing assembly also has a liquid storage function. Even if a small amount of water seeps into the first seal and the second seal, the axial channel and cavity of the third seal can still store the liquid, preventing the liquid from entering the shell and enhancing the storage effect.

[0066] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A shaft sealing structure for an electric tool, comprising a housing having a through hole for a rotating shaft to pass through, characterized in that: It also includes: a first sealed bearing, located on the inner end surface side of the housing and axially confined within the through hole; a second sealed bearing, located on the outer end surface side of the housing and movable in the through hole in the axial direction of the through hole; a first sealing assembly located between the first sealed bearing and the second sealed bearing, wherein the first sealing assembly is an axially deformable elastic structure to accommodate displacement of the second sealed bearing; a second sealing assembly sleeved on the rotating shaft and rotatably engaged with the rotating shaft, wherein the second sealing assembly is located between the first sealing assembly and the second sealed bearing; The first sealing assembly comprises: a first sealing ring, sleeved on the rotating shaft and with one end thereof abutting against the first sealing bearing; a second sealing ring, sleeved on the rotating shaft and having one end abutting against the second sealing assembly; the first sealing ring and the second sealing ring are abutted against each other at their facing ends, with a radial gap being left between the abutting point and the outer surface of the rotating shaft to form a cavity; a radial gap is left between the inner ring surface of the second sealing ring and the surface of the rotating shaft to form an axial channel, and the axial channel is connected to the cavity; a spring, sleeved on the outer circumference of the first sealing ring, wherein one end of the spring abuts against the back surface of the abutment connection between the first sealing ring and the second sealing ring; One end of the first sealing ring has an axial protrusion and the other end has an annular flange extending radially outward; the axial protrusion abuts the first sealed bearing and the inner annular surface of the axial protrusion is in close contact with the surface of the rotating shaft and can rotate relative to the first sealed bearing; one side of the annular flange abuts the second sealing ring and the other side abuts the spring; The second sealing assembly includes: The third sealing ring is sleeved on the rotating shaft and one end of the third sealing ring abuts against the second sealing ring. The inner ring surface of the third sealing ring is in close contact with the surface of the rotating shaft and can rotate relatively.

2. The shaft sealing structure according to claim 1, characterized in that: A first step is provided in the through hole, and a shaft shoulder is provided on the rotating shaft and located on the inner side of the housing. The first step and the shaft shoulder cooperate to limit the axial direction of the first sealed bearing in the through hole.

3. The shaft sealing structure according to claim 1, characterized in that: A second step is provided in the through hole for limiting the axial movement of the second sealing assembly toward the outer end surface of the housing; The rotating shaft is provided with a shaft ring located on the outer side of the housing for limiting the displacement of the second sealed bearing.

4. The shaft sealing structure according to claim 1, characterized in that: The first sealing assembly further comprises: a first spring seat, which is sleeved outside the axial protrusion of the first sealing ring and has a step structure that cooperates with the axial protrusion to limit the axial position; the first spring seat has a radially outer ring edge, one side of the ring edge abuts the first sealing bearing and the other side abuts the spring; The second spring seat is sleeved outside the first sealing ring and has a radially inward ring edge, one side of the ring edge abuts against the annular flange of the first sealing ring and the other side abuts against the spring.

5. The shaft sealing structure according to claim 1, characterized in that: One end of the second sealing ring has an axial protrusion and the other end has an annular flange extending radially outward. The annular flange abuts against the first sealing ring, and the axial protrusion abuts against the second sealing assembly.

6. The shaft sealing structure according to claim 1, characterized in that: At least one of the two facing end surfaces of the first sealing ring and the second sealing ring has a concave structure centered on the corresponding axial hole, so as to form the cavity when the first sealing ring and the second sealing ring are abutted and connected; The first sealing assembly further includes a first ring sleeve for packaging the first sealing ring, the second sealing ring and the spring into the first sealing assembly.

7. The shaft sealing structure according to claim 3, characterized in that: The second sealing assembly further comprises: The second ring sleeve is sleeved outside the third sealing ring and abuts against the second step. The end of the second ring sleeve facing the outer side of the shell has a ring edge that is radially inward and forms a radial gap with the outer surface of the rotating shaft. One side of the ring edge abuts the third sealing ring and the other side abuts the second sealed bearing.

8. The shaft sealing structure according to claim 7, characterized in that: The second ring sleeve is an elastic member made of a material softer than that of the third sealing ring.

9. The shaft sealing structure according to claim 7, characterized in that: The second ring sleeve is a rubber ring; the third sealing ring is a PTFE ring; and the first sealing ring and the second sealing ring are both PTFE rings.

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