Planetary reduction starter and armature shaft thereof

Abstract

A planetary reduction starter and an armature shaft thereof, the armature shaft is installed in the planetary reduction starter through a front bearing and a rear bearing, the armature shaft comprises a tooth part, an iron core matching part and a bearing mounting part arranged in sequence, the bearing mounting part is mounted and supported on the rear bearing, the front bearing is located at the rear side of the tooth part, the tooth part is a gear hobbing part, the tooth part comprises an engaging part and a bush matching part, a tool withdrawal groove is arranged between the engaging part and the bush matching part, the bush matching part is located between the engaging part and the iron core matching part, a bush is mounted on the bush matching part, the bush and the bush matching part are in interference fit, and the armature shaft is mounted and supported on the front bearing through the bush. The application also discloses the planetary reduction starter with the armature shaft. The application prolongs the service life of the starter, effectively reduces the length of the starter and lowers the production cost of the starter.

Description

Technical Field

[0001] The present invention relates to a planetary reduction starter, and more particularly to a planetary reduction starter armature shaft and a planetary reduction starter having the armature shaft. Background Technology

[0002] See Figure 1 , Figure 1 This is a cross-sectional view of a prior art starter motor. (Example) Figure 1 The starter armature support structure shown includes an armature shaft 11, a front bearing 12, a rear bearing 13, a brush end cap 14, a cover plate 15, a middle cover 16, a one-way valve 17, a planetary gear 18, and an internal gear ring 19. The front bearing 12 is disposed on the teeth of the armature 11 and mates with the cover plate 15. The cover plate 15 mates with the middle cover 16 to form a support for the front end of the armature. On the other side, the rear bearing 13 is disposed at the tail end of the armature shaft 11 and mates with the brush end cap 14 to form a support for the armature shaft 11.

[0003] See Figure 2 , Figure 2 This is a schematic diagram of a prior art armature shaft. As shown, it includes a toothed portion 111, a core mating portion 112, and a bearing mounting portion 113. The core mating portion 112 engages with the armature core laminations and generates torque through a coil to drive the armature to rotate. The bearing mounting portion 113 is used to mount the rear bearing 13 to form a support for the armature tail end.

[0004] See Figure 3 , Figure 3 This is a schematic diagram of the existing armature shaft gear. As shown, it includes a meshing part 1111, a relief groove 1112, a bearing platform 1113, and a limiting platform 1114. The meshing part 1111 meshes with the planetary gear 18, which requires the meshing part 1111 to have a certain effective meshing length (flat tooth surface).

[0005] See Figure 4 , Figure 4This is a schematic diagram of a prior art gear hob. As shown, the gear hob 21 includes a support portion 211 and a cutting tooth portion 212. The armature shaft meshing portion 1111 is machined by the cutting tooth portion 212 of the gear hob 21. This machining method forms a relief groove 1112 in the tooth portion. The gear hob 21 has a support portion 211, and a support shaft passes through the support portion 211, so it is necessary to ensure strength and machining efficiency. The cutting tooth portion 212 has a large diameter, resulting in a large radius for the relief groove 1112. The disadvantage of this armature shaft tooth structure is that, in order to ensure that the meshing portion 1111 has a certain meshing length, the relief groove needs to be moved closer to the tail end of the armature, causing the relief groove 1112 to extend to the bearing platform 1113 and the limiting platform 1114. This results in the bearing platform 1113 being an incomplete cylindrical surface, causing partial interference with the inner sleeve of the front bearing 12, leading to premature failure of the armature bearing and affecting the overall lifespan of the machine. On the other hand, the extension of the tool relief groove 1112 to the limiting stage 1114 will cause the grease inside the planetary deceleration system to flow into the motor through the tool relief groove 1112, resulting in a reduction of grease in the planetary system and premature failure.

[0006] In addition, existing technologies solve the problem of the relief groove 1112 extending to the bearing platform 1113 and the limiting platform 1114 by increasing the length of the teeth. However, increasing the length will increase the overall length of the starter, affecting the adaptability of the starter and increasing the production cost of the starter.

[0007] In existing technology, the armature gear 111 is manufactured using a circular hobbing machine, which produces a relief groove 1112. To ensure hob strength and processing efficiency, the hob diameter is set relatively large. Since the gear 111 needs to mesh with the planetary gear 18, it requires a certain length, necessitating increased machining. Simultaneously, to increase overall machine adaptability and reduce costs, the armature shaft 11 is designed to be shorter. This results in the relief groove 1112 extending to the end face of the armature bearing and even the axial positioning surface, making the mating surface between the armature shaft gear 111 and the front bearing 12 too small. Furthermore, grease inside the planetary reduction system flows through the relief groove 1112 generated during gear 111 machining to the motor system outside the planetary reduction system, causing grease reduction in the planetary reduction system, leading to abnormal wear of related components and even premature failure. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a planetary reduction starter armature shaft and a planetary reduction starter having the same, so as to solve the problem of low bearing life and poor reliability caused by the unstable support structure of the planetary reduction armature shaft of the starter in the prior art.

[0009] To achieve the above objectives, the present invention provides an armature shaft for a planetary gear starter. The armature shaft is supported and mounted within the starter via a front bearing and a rear bearing. The armature shaft includes sequentially arranged teeth, a core mating portion, and a bearing mounting portion. The bearing mounting portion is mounted and supported on the rear bearing. The front bearing is located behind the teeth. The teeth are gear hobs, each including a meshing portion and a bushing mating portion. A relief groove is provided between the meshing portion and the bushing mating portion. The bushing mating portion is located between the meshing portion and the core mating portion, and a bushing is mounted on the bushing mating portion. The bushing and the bushing mating portion are interference-fitted. The armature shaft is supported and mounted on the front bearing via the bushing.

[0010] In the aforementioned armature shaft, the bushing includes a limiting portion, a bearing mating portion, and an armature shaft mating portion. The limiting portion and the bearing mating portion are located on the outer wall of the bushing, and the armature shaft mating portion is located on the inner wall of the bushing. The front bearing is mounted on the bearing mating portion and its axial position is limited by the limiting portion.

[0011] In the aforementioned armature shaft, the bushing fitting portion and the armature shaft fitting portion are radially interference-fitted, and the end faces of the limiting portion and the engaging portion are axially fitted.

[0012] The aforementioned armature shaft, wherein the bushing is a metal material part, a non-metal material part, or a powder metallurgy sintered part.

[0013] In the aforementioned armature shaft, the diameter of the core mating portion is smaller than the diameter of the bushing mating portion, and the bushing is assembled from the bearing mounting portion.

[0014] In the aforementioned armature shaft, the diameter of the bearing mating portion is greater than, less than, or equal to the root circle diameter of the meshing portion.

[0015] In the aforementioned armature shaft, the diameter of the bearing mating portion is larger than the tooth tip circle diameter of the meshing portion.

[0016] In the aforementioned armature shaft, the diameter of the limiting portion is larger than the inner diameter of the outer sleeve of the front bearing.

[0017] In the aforementioned armature shaft, the width of the bearing mating portion is greater than or equal to the width of the front bearing.

[0018] In the aforementioned armature shaft, the tool relief groove extends from the meshing portion to the surface of the bushing mating portion, and the inner side of the armature shaft mating portion closes the tool relief groove.

[0019] In the aforementioned armature shaft, the front bearing is a deep groove ball bearing, needle roller bearing, or oil-impregnated bearing.

[0020] To better achieve the above objectives, the present invention also provides a planetary reduction starter, wherein the aforementioned armature shaft is included.

[0021] The technical advantages of this invention are as follows:

[0022] This invention solves the problem in the prior art where the front bearing is directly mounted on the armature shaft teeth, resulting in a mismatch between the front bearing inner sleeve and the non-cylindrical surface, leading to different interference fits and reduced bearing life, as well as unstable support. This is achieved by adding a bushing to the armature shaft teeth and mounting the front bearing on the bushing. Furthermore, by adding a bushing to the armature shaft teeth, the invention effectively prevents grease from flowing from the spline relief grooves of the planetary gear reducer into the motor system, thus avoiding grease loss and abnormal wear of starter reduction components, leading to premature failure. The armature shaft support of this invention is more stable, and grease from the planetary gear reducer is less likely to flow into the motor, thereby improving the overall lifespan of the starter and effectively reducing the overall length, making the starter more adaptable and lowering the overall production cost.

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0024] Figure 1 A cross-sectional view of a conventional starter motor;

[0025] Figure 2 This is a schematic diagram of an existing armature shaft structure;

[0026] Figure 3 This is a schematic diagram of the existing armature shaft gear structure;

[0027] Figure 4 A schematic diagram of a gear hob structure for machining armature shaft teeth using existing technology;

[0028] Figure 5 This is a schematic diagram of a planetary reduction starter structure according to an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of an armature shaft structure according to an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of a bushing structure according to an embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of the armature shaft structure according to another embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of the armature shaft structure according to another embodiment of the present invention.

[0033] Among them, the attached reference numerals

[0034] 11 Armature shaft

[0035] 111 Teeth

[0036] 1111 Meshing part

[0037] 1112 Unsinking Groove

[0038] 1113 Bearing stand

[0039] 1114 Limiting Platform

[0040] 1115 Bushing mating part

[0041] 112 Core mating part

[0042] 113 Bearing Installation Section

[0043] 114 Bushing

[0044] 1141 Limiting Part

[0045] 1142 Bearing mating part

[0046] 1143 Armature shaft mating part

[0047] 12 front bearings

[0048] 13 Rear Bearing

[0049] 14 Brush end caps

[0050] 15 Cover plate

[0051] 16 Middle Cover

[0052] 17 One-way transceivers

[0053] 171 Axle Pin

[0054] 18 Planetary Gears

[0055] 19 Internal gear ring

[0056] 21 Gear hob

[0057] 211 Support section

[0058] 212 Toothed section Detailed Implementation

[0059] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings:

[0060] See Figure 5 , Figure 5This is a schematic diagram of a planetary geared starter according to an embodiment of the present invention. The planetary geared starter of the present invention includes an armature shaft 11, a front bearing 12, a rear bearing 13, a brush end cap 14, a cover plate 15, a middle cover 16, a one-way valve 17, a planetary gear 18, and an internal gear ring 19. The front bearing 12 is disposed on the teeth 111 of the armature shaft 11. The front bearing 12 is mounted on the cover plate 15, and the cover plate 15 is mounted on the middle cover 16. The front bearing 12 cooperates with the cover plate 15, and the cover plate 15 cooperates with the middle cover 16 to provide support for the front end of the armature shaft; that is, the armature shaft 11 is supported on the cover plate 15 by the front bearing 12. The rear bearing 13 is disposed at the tail end of the armature shaft 11 and cooperates with the brush end cap 14 to provide support for the armature shaft 11; that is, the tail end of the armature shaft 11 is supported on the brush end cap 14 by the rear bearing 13. The armature shaft 11 does not form a supporting structure with the one-way valve 17. The front bearing 12 and the rear bearing 13 can be deep groove ball bearings, needle roller bearings, or oil-impregnated bearings. The composition, structure, relative positions, connection relationships, and functions of other parts of this planetary reducer starter are all mature existing technologies, and therefore will not be described in detail here. Only the armature shaft 11 of this invention will be described in detail below.

[0061] See Figure 6 , Figure 6 This is a schematic diagram of an armature shaft structure according to an embodiment of the present invention. The armature shaft 11 of the present invention is mounted in a starter motor via a front bearing 12 and a rear bearing 13. The armature shaft 11 includes sequentially arranged teeth 111, a core mating portion 112, and a bearing mounting portion 113. The bearing mounting portion 113 is mounted and supported on the rear bearing 13. The teeth 111 include a meshing portion 1111 and a bushing mating portion 1115. The meshing portion 1111 has a certain effective meshing length to ensure meshing with the planetary gear 18. A relief groove 1112 is provided between the meshing portion 1111 and the bushing mating portion 1115. The bushing mating portion 1115 is located between the meshing portion 1111 and the core mating portion 112. A bushing 114 is mounted on the bushing mating portion 1115, and the armature shaft 11 is mounted and supported on the front bearing 12 via the bushing 114. The meshing part 1111 can be machined by a hobbing machine. After machining, the axial non-effective meshing length of the meshing part 1111 is removed, and the bushing 114 is installed at this position. The relief groove 1112 of the meshing part 1111 extends to the surface of the bushing mating part 1115. The inner side of the armature shaft mating part 1143 closes the relief groove 1112. That is, by setting the bushing 114, the relief groove 1112 is closed by the inner side of the bushing 114, thereby avoiding the problem of grease inside the planetary reduction system flowing to other parts of the motor through the relief groove 1112 of the tooth part 111, and extending the service life of the starter planetary system and the whole machine.

[0062] See Figure 7 , Figure 7 This is a schematic diagram of a bushing structure according to an embodiment of the present invention. In this embodiment, the bushing 114 includes a limiting portion 1141, a bearing mating portion 1142, and an armature shaft mating portion 1143. The limiting portion 1141 and the bearing mating portion 1142 are located on the outer wall of the bushing 114, and the armature shaft mating portion 1143 is located on the inner wall of the bushing 114. The width of the bearing mating portion 1142 is greater than or equal to the width of the front bearing 12. The front bearing 12 is mounted on the bearing mating portion 1142 and its axial position is limited by the limiting portion 1141. The bushing mating portion 1115 is mounted inside the armature shaft mating portion 1143. That is, the bearing mating portion 1142 mates with the front bearing 12 and axially mates with the limiting portion 1141 to limit its axial position. The limiting portion 1141 is preferably a limiting boss used to limit the axial position of the front bearing 12.

[0063] In this embodiment, the bushing mating portion 1115 and the armature shaft mating portion 1143 are preferably radially interference-fitted, and the limiting portion 1141 and the end face of the meshing portion 1111 are axially fitted. The diameter of the core mating portion 112 is smaller than the diameter of the bushing mating portion 1115, and the bushing 114 can be assembled and pressed into the bushing mating portion 1115 of the armature shaft 11 from the tail end of the armature shaft 11 in the direction of the bearing mounting portion 113. In this embodiment, it is preferred that the diameter of the bearing mating portion 1142 is larger than the root circle diameter of the meshing portion 1111, thereby ensuring that grease in the planetary reduction gear cannot pass through the gear root. Of course, as needed, the diameter of the bearing mating portion 1142 can also be smaller than or equal to the root circle diameter of the meshing portion 1111, and there is no limitation thereto. Alternatively, the diameter of the bearing mating portion 1142 can be set larger than the tooth tip circle diameter of the meshing portion 1111. This structure allows the front bearing 12 to be pressed in from the front end of the armature shaft 11. The diameter of the limiting portion 1141 is larger than the inner diameter of the outer sleeve of the front bearing 12, which ensures an effective contact area. However, its height should not exceed the inner diameter of the outer sleeve of the front bearing 12 by too much; otherwise, abnormal wear may occur due to an interference fit between the bearing oil seal and the limiting portion 1141 of the bushing 114.

[0064] The present invention adds a bushing 114 to the tooth 111 of the armature shaft 11, so that the tooth 111 and the front bearing 12 are complete cylindrical surfaces. Compared with the prior art, this structure increases the axial contact length between the tooth 111 and the bearing and increases the circumferential contact area, so that the bearing inner side is subjected to uniform force, thereby improving the support stability of the armature shaft 11, improving the working efficiency of the starter, reducing the overall length of the machine, and reducing material and process costs.

[0065] See Figure 8 , Figure 8 This is a schematic diagram of an armature shaft structure according to another embodiment of the present invention. This embodiment is similar to... Figure 6 The difference in the illustrated embodiment is that the bearing mating portion 1142 of the bushing 114 is smaller than the tip circle diameter of the tooth portion 111 of the armature shaft 11. This structure is suitable for situations where a larger size of the front bearing 12 cannot be selected due to space constraints, such as space issues mainly caused by the armature wire twisting and occupying radial space of the bearing; or smaller bearings can be used to reduce costs. The front bearing 12 is pre-installed on the bushing 114, and the bushing 114, after the bearing is press-fitted, is installed onto the bushing mating portion 1115 of the armature shaft 11. The diameter of the core mating portion 112 of the armature shaft 11 is smaller than that of the bushing mating portion 1115. The diameter of the bearing mating portion 1142 of the bushing 114 is larger than the root circle diameter of the meshing portion 1111, preventing planetary reduction gear grease from flowing to the planetary reduction gear through the relief groove 1112. The bushing 114 mates with the drive shaft tooth portion 111 and is axially positioned. The width of the bearing mating part 1142 of the bushing 114 is greater than the width of the front bearing 12. The front bearing 12 is axially positioned by the limiting part 1141 of the bushing 114, and the diameter of the limiting part 1141 is greater than the inner diameter of the outer sleeve of the front bearing 12, thereby ensuring the axial position of the bearing.

[0066] See Figure 9 , Figure 9 This is a schematic diagram of an armature shaft structure according to another embodiment of the present invention. The difference from the first embodiment is that the bushing 114 is not axially positioned with the teeth 111 of the armature shaft 11. The axial position is defined by a tooling for pressing the bushing 114, thus eliminating the need for bearing positioning with the teeth 111.

[0067] Compared with the prior art, the structure of the present invention increases the axial contact length between the teeth 111 of the armature shaft 11 and the front bearing 12, and improves the circumferential contact area, resulting in uniform force distribution on the inner side of the bearing. This improves the armature support stability, increases the starter's working efficiency, and reduces the overall length of the machine. Furthermore, the relief groove 1112 of the teeth 111 extends to the surface of the bushing mating part 1115. By setting the bushing 114, the relief groove 1112 is closed by the inner surface of the bushing 114, thus preventing grease inside the planetary reduction system from flowing to other parts of the motor via the relief groove 1112 of the teeth 111, extending the service life of the starter's planetary system. Simultaneously, it solves the problem of limited armature space preventing the installation of larger bearings, or reduces the size of the front bearing 12, effectively reducing starter costs and improving product competitiveness.

[0068] This invention solves the problems of insufficient mating surface and poor sealing of planetary gear reducers, improves product performance, shortens the overall length, reduces production costs, and improves product adaptability.

[0069] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. An armature shaft for a planetary geared starter, the armature shaft being supported and mounted within the starter via a front bearing and a rear bearing, the armature shaft comprising sequentially arranged teeth, a core mating portion, and a bearing mounting portion, the bearing mounting portion being mounted and supported on the rear bearing, and the front bearing being located behind the teeth, characterized in that, The gear teeth are machined using a gear hob, and include a meshing portion and a bushing mating portion. A relief groove is provided between the meshing portion and the bushing mating portion. The bushing mating portion is located between the meshing portion and the core mating portion, and a bushing is installed on the bushing mating portion to reduce the size of the front bearing and to make the gear teeth and the front bearing have a complete cylindrical surface fit. The meshing portion is machined by a hob, and after machining, the axial non-effective meshing length of the meshing portion is removed to install the bushing. The relief groove extends to the surface of the bushing mating portion and is closed by the inner surface of the bushing. The bushing and the bushing mating portion have an interference fit, and the armature shaft is mounted and supported on the front bearing through the bushing. The diameter of the core mating portion is smaller than the diameter of the bushing mating portion, and the bushing is assembled and pressed into the bushing mating portion of the armature shaft from the tail end of the armature shaft in the direction of the bearing mounting portion. The bushing includes a limiting part, a bearing mating part, and an armature shaft mating part. The limiting part and the bearing mating part are located on the outer wall of the bushing, and the armature shaft mating part is located on the inner wall of the bushing. The inner surface of the armature shaft mating part closes the tool relief groove. The front bearing is mounted on the bearing mating part and its axial position is limited by the limiting part. The limiting part is a limiting boss and is axially fitted with the end face of the meshing part. The diameter of the limiting part is larger than the inner diameter of the outer sleeve of the front bearing to ensure an effective contact area. The bushing fitting part and the armature shaft fitting part are radially interference fit, and the end face of the limiting part and the meshing part are axially fitted; the diameter of the bearing fitting part is larger than the root circle diameter of the meshing part to ensure that the planetary reduction gear grease cannot pass through the root of the gear teeth; The tool relief groove extends from the meshing part to the surface of the bushing mating part, and the inner side of the armature shaft mating part closes the tool relief groove to prevent grease inside the planetary gear reducer from flowing to other parts of the motor through the tool relief groove.

2. The armature shaft as claimed in claim 1, characterized in that, The bushing can be a metal part, a non-metal part, or a powder metallurgy sintered part.

3. The armature shaft as described in claim 1, characterized in that, The diameter of the bearing mating part is larger than the tooth tip circle diameter of the meshing part.

4. The armature shaft as claimed in claim 1, characterized in that, The width of the bearing mating portion is greater than or equal to the width of the front bearing.

5. The armature shaft as claimed in claim 1, characterized in that, The front bearing is a deep groove ball bearing, needle roller bearing, or oil-impregnated bearing.

6. A planetary reduction starter motor, characterized in that, Includes the armature shaft as described in any one of claims 1-5.

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