Ball bearing assembly tool and method

Abstract

The invention provides a ball bearing assembling tool and an assembling method, the ball bearing assembling tool is used for assembling an inner ring of a ball bearing with an outer ring installed on a shell to a rotating shaft, and the ball bearing assembling tool is characterized by comprising a bearing positioning sleeve, a pulling piece and a rotating shaft positioning sleeve in threaded connection with the bearing positioning sleeve; and the structural member is arranged on the bearing positioning sleeve. The assembly requirement that the inner ring and the outer ring of the bearing adopt interference design can be met.

Description

Technical Field

[0001] This invention relates to the field of bearing assembly technology, and in particular to a ball bearing assembly fixture and assembly method. Background Technology

[0002] The power drive system of new energy vehicles has transformed from the traditional "engine + gearbox" power unit to a "motor + gearbox" power unit. The "motor + gearbox" power system exhibits different driving characteristics from that of traditional gasoline vehicles: First, the motor speed is high, generally above 16,000 rpm, and 20,000 rpm electric drive units are also quite common; second, the noise level requirements for the electric drive unit are very stringent, which is also one of the key and challenging technologies in the electric drive system of new energy vehicles.

[0003] High speeds and high quietness inevitably pose technical challenges to power transmission systems. As an essential basic unit in power transmission, the positioning accuracy and positioning method of bearings determine the performance of electric drive systems at high speeds.

[0004] In electric drive products for new energy vehicles, the motor shaft and gearbox shaft, due to their high rotational speeds, generally use ball bearings for positioning and support. Traditionally, the inner ring of the ball bearing has an interference fit with the shaft, while the outer ring has a clearance fit with the housing. This design facilitates assembly; the bearing can be pressed onto the shaft first, and then the bearing bore on the housing can be inserted into the corresponding bearing outer ring for assembly. However, the bearing's support accuracy is affected by the clearance between the outer ring and the housing. Furthermore, the high rotational speed of the shaft system causes the bearing outer ring to rotate relative to the housing. Excessive relative rotation not only leads to wear on the housing bore and reduced support accuracy, but can also cause bearing failure in severe cases.

[0005] To address this, an anti-creep bearing has been proposed in the prior art. It uses a groove on the outer ring of the bearing and a special material installed in the groove to ensure that there is no relative rotation between the outer ring and the housing. However, its structure is complex and the material filling the groove has high performance requirements, which leads to increased manufacturing costs. Moreover, it can only prevent the outer ring from creeping relative to the housing and cannot improve the fitting accuracy between the outer ring and the housing.

[0006] The applicant's research revealed that if both the inner and outer rings of a ball bearing are interference-fitted with their mating parts, it not only reduces the risk of creep but also improves the bearing's positioning accuracy, enhances the stability of the power system, and improves the product's NVH performance. However, the interference fit design of the inner and outer rings of the ball bearing can lead to assembly processes that fail to meet the bearing's assembly requirements. Improper assembly could potentially damage the bearing, thereby reducing its positioning accuracy and affecting the operating performance of the power system.

[0007] Therefore, it is necessary to develop a ball bearing assembly tooling and assembly method in which both the inner and outer rings of the ball bearing are interference fits, so as to meet the assembly requirements of the bearing inner and outer rings being designed with interference fits. Summary of the Invention

[0008] The purpose of this invention is to provide a ball bearing assembly fixture and assembly method to solve the problem that existing ball bearing assembly fixtures and assembly methods are prone to damaging the bearing.

[0009] To solve the above-mentioned technical problems, the present invention provides a ball bearing assembly fixture for assembling the inner ring of a ball bearing, whose outer ring is already mounted on a housing, onto a rotating shaft. The ball bearing assembly fixture includes a bearing positioning sleeve, a pull member, a rotating shaft positioning sleeve threadedly connected to the bearing positioning sleeve, and a structural component mounted on the bearing positioning sleeve. When assembling the ball bearing, the ball bearing assembly fixture assembles the ball bearing into the housing, ensuring an interference fit between the outer ring of the ball bearing and the housing. The bearing positioning sleeve and the rotating shaft positioning sleeve are connected together via a threaded connection. The structural component is then connected to the bearing positioning sleeve. The bearing positioning sleeve is placed on the inner ring end face of the ball bearing to restrict the movement of the inner ring of the ball bearing along a first direction. The structural component is placed in the limiting component on the housing. The rotating shaft is placed in the rotating shaft positioning sleeve, and the rotating shaft is axially fixed on the rotating shaft positioning sleeve by the pulling component. During the rotation of the rotating shaft positioning sleeve, the housing restricts the rotation of the bearing positioning sleeve, and the rotating shaft positioning sleeve rotates and moves relative to the bearing positioning sleeve along the first direction. The rotating shaft moves relative to the bearing positioning sleeve along the first direction, thereby assembling the ball bearing onto the rotating shaft.

[0010] Optionally, the limiting member is a slot formed on the housing.

[0011] Optionally, the limiting member and the structural member are clearance-fitted in the circumferential direction of the rotating shaft.

[0012] Optionally, the groove walls on both sides of the limiting member are structural planes, and the end face of the structural member that mates with the structural plane is a convex curved surface.

[0013] Optionally, the pulling member is a retaining ring, the outer circumferential surface of the rotating shaft is provided with a groove that mates with the retaining ring, and the inner ring of the rotating shaft positioning sleeve is provided with a convex ring that mates with the axial end face of the retaining ring.

[0014] Optionally, a thrust bearing is provided between the retaining ring and the convex ring.

[0015] Optionally, the convex ring and the rotating shaft are fitted with a clearance.

[0016] Optionally, the rotating shaft positioning sleeve is threadedly connected to the inner ring of the bearing positioning sleeve.

[0017] Optionally, a rotating sleeve is also included, which is detachably and fixedly connected to the rotating shaft positioning sleeve in the radial direction.

[0018] This embodiment also provides a ball bearing assembly method, including: assembling the ball bearing into a housing, and ensuring an interference fit between the outer ring of the ball bearing and the housing; connecting a bearing positioning sleeve and a shaft positioning sleeve together via a threaded connection; connecting a structural component to the bearing positioning sleeve, placing the bearing positioning sleeve on the inner ring end face of the ball bearing to restrict the movement of the inner ring of the ball bearing along a first direction, and placing the structural component in a limiting component; placing a shaft in a shaft positioning sleeve, and axially fixing the shaft to the shaft positioning sleeve by a pulling component; during the rotation of the shaft positioning sleeve, the housing restricts the rotation of the bearing positioning sleeve, and the shaft positioning sleeve rotates and moves relative to the bearing positioning sleeve along the first direction, while the shaft moves relative to the bearing positioning sleeve along the first direction, thereby assembling the ball bearing onto the shaft.

[0019] The ball bearing assembly fixture and assembly method provided by this invention have the following beneficial effects: First, during the rotation of the positioning sleeve, the ball bearing remains stationary while the shaft moves in the first direction. In this way, the inner ring of the ball bearing, which is in relative motion, can be mounted on the shaft, thereby achieving an interference fit between the inner ring of the ball bearing and the shaft.

[0020] Secondly, since the housing restricts the rotation of the bearing positioning sleeve during the rotation of the shaft positioning sleeve, the bearing positioning sleeve and the limiting member do not rotate relative to each other during the rotation of the shaft positioning sleeve and its movement and rotation along the first direction. That is, the inner ring of the ball bearing does not rotate relative to the outer ring during the assembly of the ball bearing. Furthermore, since the shaft positioning sleeve drives the shaft to move along the first direction through the pulling member to assemble the inner ring of the deep groove ball bearing onto the shaft, the shaft hardly rotates during the assembly of the ball bearing. In this way, the inner ring of the ball bearing and the shaft do not rotate relative to each other, but only move relative to each other, which can reduce the wear of the bearing during the assembly process and make the force acting on the inner ring of the ball bearing uniform. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural schematic diagram of a ball bearing assembly fixture in one embodiment of the present invention; Figure 2 This is a top view schematic diagram of the ball bearing assembly fixture in one embodiment of the present invention; Figure 3 yes Figure 2A sectional view of the ball bearing assembly fixture along line AA. Figure 4 This is a three-dimensional structural schematic diagram of the rotating shaft positioning sleeve of the ball bearing assembly fixture in an embodiment of the present invention; Figure 5 This is a three-dimensional structural diagram of the bearing positioning sleeve of the ball bearing assembly fixture in an embodiment of the present invention; Figure 6 This is a top view of the bearing positioning sleeve of the ball bearing assembly fixture in an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 100-Ball bearing; 110-Outer ring; 120-Inner ring; 200-Bearing locating sleeve; 300-Shaft locating sleeve; 310-Convex ring; 400-Structural component; 410-Reinforcing rib; 500-Pull component; 600-Housing; 610-Limiting component; 700-Shaft; 800-Thrust bearing; 900-Rotating sleeve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 , Figure 1 This is a three-dimensional structural diagram of a ball bearing assembly fixture in one embodiment of the present invention. Figure 2 This is a top view schematic diagram of the ball bearing assembly fixture in one embodiment of the present invention. Figure 3 yes Figure 2 A sectional view of the ball bearing assembly fixture along line AA. Figure 4 This is a three-dimensional structural diagram of the rotating shaft positioning sleeve 300 of the ball bearing assembly fixture in an embodiment of the present invention. Figure 5 This is a three-dimensional structural diagram of the bearing positioning sleeve 200 of the ball bearing assembly fixture in an embodiment of the present invention. Figure 6This is a top view of the bearing positioning sleeve 200 of the ball bearing assembly fixture in this embodiment of the invention. This embodiment provides a ball bearing assembly fixture for assembling the inner ring 120 of a ball bearing 100, whose outer ring 110 is already mounted on a housing 600, onto a rotating shaft 700. The ball bearing assembly fixture includes a bearing positioning sleeve 200, a pulling member 500, a rotating shaft positioning sleeve 300 threadedly connected to the bearing positioning sleeve 200, and a structural member 400 mounted on the bearing positioning sleeve 200. When assembling the ball bearing 100, the ball bearing assembly fixture assembles the ball bearing 100 into the housing 600, ensuring an interference fit between the outer ring 110 of the ball bearing 100 and the housing 600. The bearing positioning sleeve 200 and the rotating shaft positioning sleeve 300 are connected together by a threaded fit. The structural member 400 is then connected to the housing 600. The bearing positioning sleeves 200 are connected together and placed on the end face of the inner ring 110 of the ball bearing 100 to restrict the movement of the inner ring 110 of the ball bearing 100 along the first direction. The structural member 400 is placed in the limiting member 610 on the housing 600. The rotating shaft 700 is placed in the rotating shaft positioning sleeve 300 and the rotating shaft 700 is axially fixed on the rotating shaft positioning sleeve 300 by the pulling member 500. During the rotation of the rotating shaft positioning sleeve 300, the housing 600 restricts the rotation of the bearing positioning sleeve 200, and the rotating shaft positioning sleeve 300 rotates and moves relative to the bearing positioning sleeve 200 along the first direction. The rotating shaft 700 moves relative to the bearing positioning sleeve 200 along the first direction, thereby assembling the ball bearing 100 onto the rotating shaft 700.

[0030] Thus, during the rotation of the rotating shaft positioning sleeve 300, the ball bearing 100 remains stationary, while the rotating shaft 700 moves along the first direction. In this way, the inner ring 120 of the relatively moving ball bearing 100 can be mounted on the rotating shaft 700, thereby achieving an interference fit between the inner ring 120 of the ball bearing 100 and the rotating shaft 700 without damaging the steel balls and the inner and outer ring grooves of the ball bearing.

[0031] Because the housing 600 restricts the rotation of the bearing positioning sleeve 200 during the rotation of the shaft positioning sleeve 300, the bearing positioning sleeve 200 and the limiting member 610 do not rotate relative to each other during the rotation of the shaft positioning sleeve 300 and the movement and rotation of the shaft positioning sleeve 300 along the first direction. That is to say, the inner ring 120 of the ball bearing 100 does not rotate relative to the outer ring 110 during the assembly of the ball bearing 100. Furthermore, since the shaft positioning sleeve 300 drives the shaft 700 to move along the first direction through the pulling member to assemble the inner ring 120 of the deep groove ball bearing onto the shaft 700, the shaft 700 also hardly rotates during the assembly of the ball bearing 100. In this way, the inner ring 120 of the ball bearing 100 and the shaft 700 do not rotate relative to each other, but only move relative to each other, which can reduce the wear of the bearing during the assembly process and make the force acting on the inner ring 120 of the ball bearing 100 uniform.

[0032] In addition, the rotation of the structural component 400 relative to the housing 600 can be restricted by the cooperation of the limiting component 610 and the structural component 400, thereby restricting the rotation of the bearing positioning sleeve 200 relative to the housing 600. This has the effect of simple structure and convenient operation.

[0033] Furthermore, rotating the positioning sleeve 300 can synchronously drive the rotating shaft 700 to move, without the need for additional tools or step-by-step operations, significantly improving assembly efficiency.

[0034] In this embodiment, the ball bearing assembly fixture is suitable for assembling ball bearings 100 in the automotive field. In this field, the ball bearing 100 and the shaft 700 have a small interference fit, so that the ball bearing 100 can be press-fitted into the shaft 700 without damaging the ball bearing 100.

[0035] In this embodiment, the housing 600 restricts the outer ring 110 of the ball bearing 100 from moving in a direction opposite to the first direction.

[0036] Specifically, a countersunk hole is provided on the housing 600, which is used to restrict the outer ring 110 of the ball bearing 100 from moving in a direction opposite to the first direction.

[0037] Preferably, the limiting member 610 is a slot formed on the housing 600, which simplifies the structure and installation of the ball bearing assembly fixture and reduces the processing and manufacturing cost of the housing 600. In other embodiments, the limiting member 610 may be a slot or a protrusion with a groove, or a structure that can cooperate with the structural member 400 and restrict the rotation of the structural member 400.

[0038] Furthermore, the limiting member 610 and the structural member 400 are in clearance fit in the circumferential direction of the rotating shaft 700. Thus, when the rotating shaft positioning sleeve 300 rotates in a predetermined direction, causing the rotating shaft 700 to move along a first direction, the groove wall on one side of the limiting member 610 can quickly abut against the structural member 400, thereby limiting the structural member 400 and consequently limiting the bearing positioning sleeve 200. After the rotating shaft positioning sleeve 300 separates from the rotating shaft 700, when the rotating shaft positioning sleeve 300 rotates in a direction opposite to the predetermined direction, the groove wall on the other side of the limiting member 610 can quickly abut against the structural member 400. The contact action effectively limits the positioning of the structural component 400, which in turn limits the positioning of the bearing positioning sleeve 200. This allows the rotating shaft positioning sleeve 300 to move and rotate relative to the bearing positioning sleeve 200 in a direction opposite to the first direction, preparing for the next assembly of the ball bearing 100 and facilitating industrialization. In this way, the excessive gap between the structural component 400 and the limiting component 610 can be avoided, which would cause the structural component 400 and the limiting component 610 to collide and affect the service life of both components.

[0039] Furthermore, the groove walls on both sides of the limiting member 610 are structural planes, and the end face of the structural member 400 that mates with the structural plane is a convex curved surface. This allows for smoother contact between the structural member 400 and the limiting member 610, reducing the impact of impacts on the ball bearing 100 during assembly due to the gap between the structural member 400 and the limiting member 610. In other embodiments, the convex curved surface is preferably a cylindrical surface.

[0040] Preferably, the bearing positioning sleeve 200 is integrally formed with the structural component 400.

[0041] Furthermore, the structural component 400 is provided with reinforcing ribs 410. This improves the connection strength between the structural component 400 and the bearing positioning sleeve 200.

[0042] Preferably, the pulling member 500 is a retaining ring, and the outer circumferential surface of the rotating shaft 700 is provided with a groove that mates with the retaining ring. The inner ring of the rotating shaft positioning sleeve 300 is provided with a convex ring 310 that mates with the axial end face of the retaining ring. Thus, when the rotating shaft positioning sleeve 300 moves along the first direction, the convex ring 310 contacts the axial end face of the retaining ring, driving the retaining ring and the rotating shaft 700 to move along the first direction. In other embodiments, the pulling member 500 may also be other structures, such as a double nut that is threadedly connected to the rotating shaft 700.

[0043] Preferably, a thrust bearing 800 is provided between the retaining ring and the convex ring 310, which can withstand a large axial force and at the same time reduce the friction between the two relatively rotating objects (convex ring 310 and retaining ring).

[0044] Preferably, the convex ring 310 and the rotating shaft 700 are fitted with a clearance to prevent the rotating shaft 700 from skewing during assembly.

[0045] Preferably, the shaft positioning sleeve 300 is threadedly connected to the inner ring of the bearing positioning sleeve 200, which simplifies the structure of the ball bearing assembly fixture, saves materials, and improves the stability of the ball bearing assembly fixture. In other embodiments, it can also be threadedly connected to the outer ring of the bearing positioning sleeve 200.

[0046] Preferably, the ball bearing assembly fixture further includes a rotating sleeve 900, which is radially detachably fixed to the shaft positioning sleeve 300. For example, the rotating sleeve 900 and the shaft positioning sleeve 300 can be radially connected by a pin, allowing the rotating sleeve 900 to move axially relative to the shaft positioning sleeve 300 but not to rotate about the axial direction. This separate design of the rotating sleeve 900 and the shaft positioning sleeve 300 reduces the number of parts requiring high machining precision, thus lowering manufacturing costs. Furthermore, it facilitates the replacement of different rotating sleeves 900 to connect with different press-fitting machines, improving versatility.

[0047] This embodiment also provides a method for assembling a ball bearing 100, including: The ball bearing 100 is assembled into the housing 600, and the outer ring 110 of the ball bearing 100 is interference-fitted with the housing 600. The bearing positioning sleeve 200 and the shaft positioning sleeve 300 are connected together by a threaded connection; The structural component 400 is connected to the bearing positioning sleeve 200, the bearing positioning sleeve 200 is placed on the end face of the inner ring 120 of the ball bearing 100 to restrict the movement of the inner ring 120 of the ball bearing 100 in the first direction, and the structural component 400 is placed in the limiting component 610. The rotating shaft 700 is placed in the rotating shaft positioning sleeve 300, and the rotating shaft 700 is axially fixed on the rotating shaft positioning sleeve 300 by the pulling member 500; During the rotation of the shaft positioning sleeve, the housing restricts the rotation of the bearing positioning sleeve, and the shaft positioning sleeve rotates and moves relative to the bearing positioning sleeve in a first direction. The shaft moves relative to the bearing positioning sleeve in the first direction, thereby assembling the ball bearing onto the shaft.

[0048] Specifically, the pulling member 500 is a retaining ring, the outer circumferential surface of the rotating shaft 700 is provided with a groove that mates with the retaining ring, and the inner ring of the rotating shaft positioning sleeve 300 is provided with a convex ring 310 that mates with the axial end face of the retaining ring.

[0049] The assembly method of the ball bearing 100 also includes radially detachably fixing the rotating sleeve 900 to the rotating shaft positioning sleeve 300.

[0050] The ball bearing in the above embodiments is preferably a deep groove ball bearing. In the above embodiments, the outer ring of the ball bearing and the housing can be either an interference fit or a clearance fit.

[0051] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A ball bearing assembly fixture for assembling the inner ring of a ball bearing, whose outer ring is already mounted on a housing, onto a rotating shaft, characterized in that, The ball bearing assembly fixture includes a bearing positioning sleeve, a pull member, a shaft positioning sleeve threadedly connected to the bearing positioning sleeve, and a structural component mounted on the bearing positioning sleeve. When assembling the ball bearing, the ball bearing assembly fixture assembles the ball bearing into the housing, ensuring an interference fit between the outer ring of the ball bearing and the housing. The bearing positioning sleeve and the shaft positioning sleeve are connected together via a threaded connection. The structural component is connected to the bearing positioning sleeve. The bearing positioning sleeve is then placed on the inner ring end face of the ball bearing. The inner ring of the ball bearing is restricted from moving in a first direction, and the structural member is placed in the limiting member on the housing. The shaft is placed in the shaft positioning sleeve, and the shaft is axially fixed on the shaft positioning sleeve by the pulling member. During the rotation of the shaft positioning sleeve, the housing restricts the rotation of the bearing positioning sleeve, and the shaft positioning sleeve rotates and moves relative to the bearing positioning sleeve in the first direction. The shaft moves relative to the bearing positioning sleeve in the first direction, thereby assembling the ball bearing onto the shaft.

2. The ball bearing assembly fixture as described in claim 1, characterized in that, The limiting component is a slot formed on the housing.

3. The ball bearing assembly fixture as described in claim 2, characterized in that, The limiting member and the structural member are in clearance fit in the circumferential direction of the rotating shaft.

4. The ball bearing assembly fixture as described in claim 3, characterized in that, The groove walls on both sides of the limiting member are structural planes, and the end face of the structural member that mates with the structural plane is a convex curved surface.

5. The ball bearing assembly fixture as described in claim 1, characterized in that, The pulling component is a retaining ring, and the outer circumferential surface of the rotating shaft is provided with a groove that mates with the retaining ring. The inner ring of the rotating shaft positioning sleeve is provided with a convex ring that mates with the axial end face of the retaining ring.

6. The ball bearing assembly fixture as described in claim 5, characterized in that, A thrust bearing is provided between the retaining ring and the convex ring.

7. The ball bearing assembly fixture as described in claim 5, characterized in that, The convex ring and the rotating shaft are fitted with a clearance.

8. The ball bearing assembly fixture as described in claim 1, characterized in that, The rotating shaft positioning sleeve is threadedly connected to the inner ring of the bearing positioning sleeve.

9. The ball bearing assembly fixture as described in claim 1, characterized in that, It also includes a rotating sleeve, which is detachably and fixedly connected to the rotating shaft positioning sleeve in the radial direction.

10. A method for assembling a ball bearing, characterized in that, include: The ball bearing is assembled into the housing, and the outer ring of the ball bearing is interference-fitted with the housing. The bearing positioning sleeve and the shaft positioning sleeve are connected together by a threaded fit. The structural component is connected to the bearing positioning sleeve, the bearing positioning sleeve is placed on the inner ring end face of the ball bearing to restrict the inner ring of the ball bearing from moving in the first direction, and the structural component is placed in the limiting component. The rotating shaft is placed in the rotating shaft positioning sleeve, and the rotating shaft is axially fixed on the rotating shaft positioning sleeve by the pulling member; During the rotation of the shaft positioning sleeve, the housing restricts the rotation of the bearing positioning sleeve, and the shaft positioning sleeve rotates and moves relative to the bearing positioning sleeve in the first direction. The shaft moves relative to the bearing positioning sleeve in the first direction, thereby assembling the ball bearing onto the shaft.

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