Rotary shaft and transmission

Abstract

This rotary shaft 10 includes a shaft body 12 in which a gear part 20 and a bearing inner ring part 31 are arranged side by side in the axial direction. The bearing inner ring part 31 has an inner ring raceway groove 32 provided on an outer peripheral surface of the bearing inner ring part 31, and a shoulder part 33 provided on the outer peripheral surface adjacent to the inner ring raceway groove 32. A tooth groove 22 of the gear part 20 is provided extending to the shoulder part 33.

Description

Rotating shaft and transmission

[0001] The present invention relates to a rotating shaft and a transmission having the rotating shaft.

[0002] A transmission mounted on an automobile includes a rotating shaft with gears, which is supported by a rolling bearing (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-110374

[0004] The rolling bearings supporting the rotating shaft as described above are lubricated by the lubricating oil used in the transmission. However, the amount of oil used in the transmission may be reduced. In such cases, if the rolling bearings are in a poor lubrication state, they may wear out prematurely or seize. Therefore, an object of the present invention is to prevent insufficient lubrication in the bearings supporting the rotating shaft.

[0005] The rotating shaft of the present invention has a shaft body on which a gear portion and a bearing inner ring portion are arranged side by side in the axial direction, the bearing inner ring portion having an inner ring raceway groove provided on the outer peripheral surface of the bearing inner ring portion and a shoulder portion provided on the outer peripheral surface adjacent to the inner ring raceway groove, and the tooth grooves of the gear portion are provided extending to the shoulder portion. The transmission of the present invention has the rotating shaft and a mating gear that meshes with the gear portion of the rotating shaft.

[0006] Fig. 1 is a schematic diagram showing a transmission having a rotating shaft of the present invention. Fig. 2 is a cross-sectional view of the rotating shaft. Fig. 3 is a cross-sectional view of a shaft body. Fig. 4 is a side view of the shaft body. Fig. 5 is a side view of the shaft body showing a modified example of the tooth grooves. Fig. 6 is an explanatory diagram showing a cross-section of the shaft body shown in Fig. 4. Fig. 7 is an explanatory diagram of a method of assembling the rotating shaft. Fig. 8 is an explanatory diagram showing a cross-section of a shaft body of a rotating shaft of another type.

[0007] <Outline of Embodiments of the Present Invention> The following is a description of outlines of embodiments of the present invention. (1) A rotating shaft according to an embodiment of the present invention has a shaft body on which a gear portion and a bearing inner ring portion are arranged side by side in the axial direction, the bearing inner ring portion having an inner ring raceway groove provided on an outer peripheral surface of the bearing inner ring portion and a shoulder portion provided on the outer peripheral surface adjacent to the inner ring raceway groove, and tooth grooves of the gear portion are provided so as to extend to the shoulder portion.

[0008] When the rotating shaft having the above-described configuration rotates, the lubricating oil present in the gear portion is guided along the tooth grooves of the gear portion, and the lubricating oil can be supplied to the inner ring raceway groove, making it possible to prevent insufficient lubrication in the bearing portion having the inner ring portion.

[0009] (2) The gear portion is a helical gear. A helical gear has a twisted tooth groove. When the rotating shaft rotates, an axial thrust is generated in the lubricating oil present in the tooth groove, accelerating the supply of the lubricating oil to the inner ring raceway groove.

[0010] (3) In the rotating shaft of (1) or (2), the axial distance between the end of the inner ring raceway and the end of the tooth groove located at the shoulder is equal to or less than the width of the inner ring raceway. The end of the tooth groove extending to the shoulder and the inner ring raceway are close to each other, and lubricating oil guided along the tooth groove is easily supplied to the inner ring raceway.

[0011] (4) In the rotating shaft of any one of (1) to (3), the axial distance between the end of the inner ring raceway and the end of the tooth groove located at the shoulder is equal to or less than the tooth height dimension of the gear portion. The end of the tooth groove extending to the shoulder and the inner ring raceway are close to each other, and lubricating oil guided along the tooth groove is easily supplied to the inner ring raceway.

[0012] (5) In the rotating shaft of any one of (1) to (4), the axial distance between the end of the inner ring raceway and the end of the tooth groove located at the shoulder is 10 millimeters or less. The end of the tooth groove extending to the shoulder and the inner ring raceway are close to each other, and lubricating oil guided along the tooth groove is easily supplied to the inner ring raceway.

[0013] (6) In the rotating shaft of any one of (1) to (5), the axial distance between the end of the inner ring raceway and the end of the tooth groove located at the shoulder is greater than zero millimeters. In this case, the inner ring raceway and the tooth groove do not penetrate each other, but the lubricating oil guided along the tooth groove is supplied to the inner ring raceway located near the tooth groove.

[0014] (7) In the rotating shaft of any one of (1) to (5), the tooth groove is continuous with the inner ring raceway groove. In this case, the tooth groove opens at the inner ring raceway groove. In other words, the tooth groove penetrates into the inner ring raceway groove. Lubricating oil guided along the tooth groove easily penetrates into the inner ring raceway groove.

[0015] (8) In the rotating shaft of any one of (1) to (7), the outer diameter of the shoulder portion where the tooth grooves are provided is smaller than the outer diameter of the gear portion. In this case, the work of mounting a plurality of rolling elements between the inner ring raceway groove and the outer ring raceway groove of the outer ring and further mounting an annular cage that holds these rolling elements becomes easy. In other words, when mounting the cage, it is easy to position a jig that supports the rolling elements between the gear portion and the shoulder portion.

[0016] (9) In the rotating shaft of (8), the outer diameter of the shoulder portion where the tooth grooves are provided is larger than the outer diameter of the tooth root of the gear portion. This configuration reliably provides a configuration in which the tooth grooves are provided extending from the gear portion to the shoulder portion.

[0017] (10) In the rotating shaft of any one of (1) to (7), the outer diameter of the shoulder portion where the tooth grooves are provided is the same as the outer diameter of the gear portion. In this case, the outer diameter of the shoulder portion is large, and when the rolling elements are balls, the function of preventing the balls from riding up onto the shoulder portion is enhanced.

[0018] (11) In the rotating shaft of any one of (1) to (10), the outer diameter of the tooth grooves provided on the shoulder portion increases toward the inner ring raceway groove, and in this case, a configuration is obtained in which the position of contact between the inner ring raceway groove and the rolling element is away from the tooth groove.

[0019] (12) The rotating shaft of (8) further comprises an outer ring having an outer ring raceway groove facing the inner ring raceway groove, a plurality of rolling elements positioned between the inner ring raceway groove and the outer ring, and an annular cage that holds the plurality of rolling elements, the cage having pockets that house the rolling elements and that open axially toward the gear portion. In this case, the work of attaching a plurality of rolling elements between the inner ring raceway groove and the outer ring raceway groove and further attaching the annular cage that holds these rolling elements becomes easy.

[0020] (13) A transmission according to an embodiment of the present invention includes a rotating shaft according to any one of (1) to (12) above, and a mating gear that meshes with the gear portion of the rotating shaft. When the rotating shaft rotates in accordance with the operation of the transmission, lubricating oil present in the gear portion can be guided along the tooth grooves of the gear portion and supplied to the inner ring raceway groove. This makes it possible to prevent insufficient lubrication in a bearing portion having a bearing inner ring portion.

[0021] <Details of the embodiment of the present invention> [Overall configuration of the transmission and rotating shaft] Fig. 1 is a schematic diagram showing a transmission having a rotating shaft of the present invention. The transmission 50 of this embodiment has a planetary gear reducer, and Fig. 1 shows a portion of it. The transmission 50 has a rotating shaft 10, a mating gear 7 that meshes with a gear unit 20 of the rotating shaft 10, and a reducer unit 55. The reducer unit 55 has a sun gear 51 attached to the rotating shaft 10, planetary gears, a planet carrier, an internal gear, and the like (not shown). Note that the transmission of the present invention may be the transmission portion of an e-axle with an integrated planetary reduction carrier. Furthermore, the transmission of the present invention may be of a type other than a planetary gear type.

[0022] FIG. 2 is a cross-sectional view of the rotating shaft 10. The various directions of the rotating shaft 10 will be described. The rotating shaft 10 has a shaft body 12 that is long in one direction. The direction parallel to the center line C of the shaft body 12 is defined as the "axial direction" of the rotating shaft 10. The direction perpendicular to the center line C is defined as the "radial direction" of the rotating shaft 10. The direction along a circle centered on the center line C is defined as the "circumferential direction" of the rotating shaft 10. The center line C is the center of rotation of the rotating shaft 10.

[0023] The rotating shaft 10 has a shaft body 12, which is a gear shaft in which the shaft and gear are integrated, and bearing components for rotatably supporting the shaft body 12. The rotating shaft 10 has, as the bearing components, an outer ring 35, a plurality of balls 36, which are rolling elements, and an annular cage 37 that holds the plurality of balls 36. The shaft body 12 has, in a part thereof, a bearing inner ring portion 31. The outer ring 35 is located radially outward of the bearing inner ring portion 31, and the plurality of balls 36 are arranged between the outer ring 35 and the bearing inner ring portion 31. The bearing inner ring portion 31, the outer ring 35, the plurality of balls 36, and the cage 37 constitute a bearing portion 30. The bearing portion 30 is a ball bearing in which a portion of the shaft body 12 serves as the inner ring (bearing inner ring portion 31).

[0024] 1 , the rotating shaft 10 has a second bearing portion 29 on the opposite side of the bearing portion 30 (first bearing portion 30) in the axial direction, with the mating gear 7 sandwiched therebetween. The second bearing portion 29 also has a configuration in which a part of the shaft body 12 serves as a bearing inner ring portion 311.

[0025] The gear portion 20 has a plurality of teeth 21 and tooth spaces 22 located between two teeth 21. The axial dimension of the gear portion 20 is set by the axial length of the mating gear 7 (see FIG. 1 ) that meshes with the gear portion 20.

[0026] Shaft body 12 is made of a steel member. A part of the steel member is gear portion 20, and another part of the steel member is bearing inner ring portion 31. In other words, a part of shaft body 12 is gear portion 20, and another part of shaft body 12 is bearing inner ring portion 31. Gear portion 20 and bearing inner ring portion 31 are provided on shaft body 12, lined up in the axial direction.

[0027] In this embodiment, shaft body 12 has a mounting shaft portion 48 for mounting a gear (sun gear 51 shown in FIG. 1 ). Mounting shaft portion 48 has, for example, a spline structure, and the gear (sun gear 51) is mounted to mounting shaft portion 48 so as to be rotatable integrally with shaft body 12. Mounting shaft portion 48 is yet another part of the steel member that constitutes shaft body 12.

[0028] The rotating shaft 10 is located in a case (not shown) of the transmission 50 (see FIG. 1 ). The lubricating oil used in the transmission 50 is used to lubricate the gear unit 20 and also the bearing unit 30.

[0029] [Configuration of Rotating Shaft 10] Figure 3 is a cross-sectional view of the shaft body 12. The bearing inner ring portion 31 has an inner ring raceway groove 32 provided on the outer peripheral surface of the bearing inner ring portion 31, and two shoulders 33, 34 provided on the outer peripheral surface adjacent to the inner ring raceway groove 32. Of the two shoulders 33, 34, the shoulder 33 on the gear portion 20 side is called the "first shoulder 33." Of the two shoulders 33, 34, the shoulder 34 on the opposite side of the inner ring raceway groove 32 from the first shoulder 33 is called the "second shoulder 34."

[0030] The outer ring 35 (see FIG. 2 ) has an outer ring raceway groove 38 that faces the inner ring raceway groove 32. A plurality of balls 36 are positioned between the bearing inner ring portion 31 (inner ring raceway groove 32) and the outer ring 35 (outer ring raceway groove 38). The cage 37 has pockets 39 that accommodate the balls 36. The cage 37 has an annular portion 371 and a plurality of pillar portions 372 that extend axially from the annular portion 371. A single pocket 39 is formed between the annular portion 371 and two circumferentially adjacent pillar portions 372. One ball 36 is accommodated in one pocket 39. The annular portion 371 is positioned on the opposite side of the balls 36 from the gear unit 20 (to the left in FIG. 2 ). The pocket 39 is shaped to open axially toward the gear unit 20 (to the right in FIG. 2 ).

[0031] 4 is a side view of the shaft body 12. The gear portion 20 of this embodiment is a helical gear. The gear portion 20 has a plurality of teeth 21 and a plurality of tooth spaces 22, and the teeth 21 and tooth spaces 22 all have the same shape.

[0032] As shown in Figure 4, the tooth grooves 22 of the gear portion 20 extend to the first shoulder 33. The shaft body 12 has a gear main body 26 with which the mating gear 7 meshes, and a gear extension 27 with which the mating gear 7 does not mesh. The gear extension 27 is a portion that continues from the gear main body 26 toward the inner ring raceway groove 32, and corresponds to the first shoulder 33 of the bearing inner ring portion 31. Since the gear main body 26 meshes with the mating gear 7, it has a complete gear shape in which the teeth 21 and tooth grooves 22 are in accordance with the gear design dimensions. In contrast, in the configuration shown in Figure 4, the gear extension 27 has a smaller diameter than the gear main body 26, and has an incomplete gear shape in which the outer peripheral side of the teeth 21 is missing.

[0033] The tooth grooves 22 of the gear main body portion 26 are referred to as "first tooth grooves 22A," and the tooth grooves 22 of the gear extension portion 27 are referred to as "second tooth grooves 22B." One first tooth groove 22A and one second tooth groove 22B form a continuous groove (one tooth groove 22). The second tooth groove 22B located in the gear extension portion 27 is a tooth groove 22 that extends to the first shoulder portion 33. In this way, the tooth grooves 22 of the gear portion 20 extend from the gear main body portion 26 to the first shoulder portion 33, which is the gear extension portion 27.

[0034] As shown in Figure 4, the end 321 of the inner ring raceway groove 32 (the end 321 on the gear portion 20 side) and the end 221 of the tooth groove 22 (the end 221 on the inner ring raceway groove 32 side) are close to each other. In Figure 4, the axial distance between the end 321 of the inner ring raceway groove 32 and the end 221 of the tooth groove 22 is indicated by "L". The axial distance L is small and is equal to or less than the width dimension W of the inner ring raceway groove 32.

[0035] As described above, the tooth grooves 22 of the gear portion 20 extend to the first shoulder portion 33. Therefore, when the rotating shaft 10 (shaft body 12) rotates, the lubricating oil present in the gear portion 20 is guided along the tooth grooves 22 and supplied to the inner ring raceway groove 32. In the present embodiment, the gear portion 20 has a helical gear configuration. A helical gear has a twisted tooth groove 22. When the rotating shaft 10 rotates, an axial thrust is generated in the lubricating oil present in the tooth grooves 22, facilitating the supply of the lubricating oil to the inner ring raceway groove 32.

[0036] In one tooth groove 22, the end 221 of the tooth groove 22 adjacent to the inner ring raceway groove 32 is located on the rear side of the rotational direction R1 of the shaft body 12. When the transmission 50 (rotating shaft 10) is mounted on an automobile, the rotational direction R1 is the direction of rotation when the automobile is moving forward. When the automobile is moving backward, the rotational direction of the rotating shaft 10 may be the opposite direction to R1. If the gear unit 20 is a helical gear, the effect of lubricating oil being guided along the tooth groove 22 and supplied to the inner ring raceway groove 32 during reverse travel is eliminated. However, when moving backward, the speed is low, and the rotational speed of the rotating shaft 10 is also low. Furthermore, the time spent moving backward is short. Therefore, lubrication of the bearing unit 30 is sufficient using the lubricating oil already supplied to the inner ring raceway groove 32.

[0037] The axial distance L between the end 321 of the inner ring raceway 32 and the end 221 of the tooth groove 22 located on the first shoulder 33 will now be described in further detail. The axial distance L can be 10 millimeters or less. The axial distance L can also be less than the tooth depth dimension S (see FIG. 3 ) of the gear portion 20. With the axial distance L as described above, the end 221 of the tooth groove 22 extending to the first shoulder 33 and the inner ring raceway 32 are close to each other, and lubricating oil guided along the tooth groove 22 is easily supplied to the inner ring raceway 32.

[0038] 4, the axial distance L is greater than zero millimeters. In this case, the inner ring raceway groove 32 and the tooth groove 22 do not penetrate each other. However, because they are close to each other, the lubricating oil guided along the tooth groove 22 exceeds the portion 331 that is linear in the axial direction for the axial distance L and is supplied to the inner ring raceway groove 32 located near the tooth groove 22.

[0039] Fig. 5 is a side view of the shaft body 12 showing a modified example of the tooth groove 22. In the configuration shown in Fig. 5, the tooth groove 22 is continuous with the inner ring raceway groove 32. In this case, the tooth groove 22 opens at the inner ring raceway groove 32. In other words, the tooth groove 22 is configured to penetrate into the inner ring raceway groove 32. The lubricating oil guided along the tooth groove 22 easily penetrates into the inner ring raceway groove 32. Furthermore, the axial distance L shown in Fig. 4 may include a case where it is zero. For example, the axial distance L is equal to or greater than zero and equal to or less than 10 millimeters.

[0040] FIG. 6 is an explanatory cross-sectional view of the shaft body 12 shown in FIG. 4 . As described above, the second tooth grooves 22B of the gear extension 27 are tooth grooves 22 formed on the first shoulder 33. The outer diameter (outer diameter of the root circle) D4 of the tooth grooves 22 formed on the first shoulder 33 increases toward the inner ring raceway 32 (left side in FIG. 6 ). The outer diameter D4 of the tooth grooves 22 formed on the first shoulder 33 of the gear extension 27 is larger than the outer diameter D3 of the first tooth grooves 22A of the gear main body 26 (D4 > D3). As shown in FIG. 6 , the outer diameter D4 of the tooth grooves 22 (second tooth grooves 22B) formed on the first shoulder 33 gradually increases toward the inner ring raceway 32. The outer diameter D3 of the first tooth grooves 22A of the gear main body 26 is constant along the axial direction.

[0041] The gear portion 20 having such tooth grooves 22 is formed by, for example, skiving. In this embodiment, the gear portion 20 is a helical gear, and when the rotating shaft 10 rotates, an axial force acts on the shaft body 12. Then, in the bearing portion 30, the balls 36 and the inner ring raceway groove 32 come into contact at a position P1 that is biased toward the gear portion 20 from the groove bottom point 32b of the inner ring raceway groove 32.

[0042] If the position of contact P1 is too close to the tooth groove 22 (second tooth groove 22B), there is a possibility that stress due to the load from the ball 36 will increase in the inner ring portion 31 of the bearing. However, as described above, the outer diameter D4 of the tooth groove 22 provided in the first shoulder portion 33 increases toward the inner ring raceway 32, making it possible to separate the position of contact P1 from the tooth groove 22. Therefore, in order to guide the lubricating oil to the inner ring raceway 32, the tooth groove 22 is extended to the first shoulder portion 33, and even if it is close to the inner ring raceway 32, it is possible to suppress the effect on the inner ring portion 31 (increase in stress).

[0043] The configuration in which the outer diameter D4 of the tooth groove 22 increases toward the inner ring raceway groove 32 is also applicable to the configuration in which the tooth groove 22 penetrates the inner ring raceway groove 32 shown in Fig. 5 and the configuration shown in Fig. 8, which will be described later. In the configuration shown in Fig. 6, the outer diameter D1 of the first shoulder 33 and the outer diameter D11 of the second shoulder 34 are the same, but they may be different.

[0044] 6 , the outer diameter D1 of the first shoulder 33 where the tooth gap 22 is provided is larger than the outer diameters (D3, D4) of the tooth bottoms 222 of the tooth gap 22. The outer diameters (D3, D4) of the tooth bottoms 222 are the outer diameters of the tooth bottom circles of the tooth gap 22. Specifically, the outer diameter D1 of the first shoulder 33 is larger than the outer diameter D3 of the tooth bottoms 222 in the first tooth gap 22A and is larger than the outer diameter D4 of the tooth bottoms 222 in the second tooth gap 22B.

[0045] The outer diameter D1 of the first shoulder portion 33, in which the tooth grooves 22 are provided, is smaller than the outer diameter D2 of the gear portion 20 (D1<D2). The outer diameter D2 of the gear portion 20 is the outer diameter of the tip circle of the teeth 21. Here, a method of assembling the rotating shaft 10 will be described with reference to Figure 7. In order to assemble the bearing portion 30 of the rotating shaft 10, the shaft body 12 is oriented so that its center line C is in the vertical direction.

[0046] An outer ring 35 is positioned on the outer peripheral side of the bearing inner ring portion 31 of the shaft body 12, and a plurality of balls 36 are mounted between the bearing inner ring portion 31 and the outer ring 35. The method of mounting the balls 36 is the same as that conventionally used. Then, the plurality of balls 36 are arranged at equal intervals in the circumferential direction. A cage 37 is brought close to the plurality of balls 36 from above, and attached so that the balls 36 are housed in the pockets 39 of the cage 37. For this purpose, the cage 37 is oriented so that the pockets 39 open toward the gear portion 20, which is on the lower side.

[0047] During this assembly, a jig 60 is used to arrange the plurality of balls 36 at equal intervals in the circumferential direction between the bearing inner ring portion 31 and the outer ring 35. The jig 60 can support the plurality of balls 36 from below. As described above, the outer diameter D1 of the first shoulder portion 33 is smaller than the outer diameter D2 of the gear portion 20 (D1<D2), so that a gap E is provided between the first shoulder portion 33 and the outer ring 35, and between the outer ring 35 and the gear portion 20 (teeth 21). By positioning the jig 60 in this gap E, the jig 60 can support the plurality of balls 36.

[0048] As described above, by configuring the outer diameter D1 of the first shoulder portion 33 to be smaller than the outer diameter D2 of the gear portion 20 (D1<D2), it becomes possible to use the jig 60, and the work of attaching the retainer 37 becomes easier.

[0049] Figure 8 is an explanatory cross-sectional view of the shaft body 12 of a rotating shaft 10 of another embodiment. In the embodiment shown in Figure 8, the outer diameter D1 of the first shoulder portion, where the tooth grooves 22 are provided, is the same as the outer diameter D2 of the gear portion 20. The outer diameter D2 of the gear portion 20 is the outer diameter of the tip circle of the teeth 21. Specifically, the outer diameter D2 of the gear body portion 26 and the outer diameter D1 of the gear extension portion 27 are the same. With this configuration, the larger outer diameter D1 of the first shoulder portion 33 enhances the function of preventing the balls 36 from riding up onto the first shoulder portion 33. In Figure 8, the boundary between the gear body portion 26 and the gear extension portion 27 is indicated by a virtual line (two-dot chain line) K.

[0050] 8, the outer diameter D4 of the tooth groove 22 formed on the first shoulder 33 also increases toward the inner ring raceway 32. The outer diameter D4 of the tooth groove 22 formed on the first shoulder 33 gradually increases toward the inner ring raceway 32. With this configuration, as in the case of the configuration shown in Fig. 6, the position P1 of contact between the inner ring raceway 32 and the ball 36 is away from the tooth groove 22. The outer diameter D3 of the first tooth groove 22A of the gear body 26 is constant along the axial direction.

[0051] [Regarding each embodiment of the rotating shaft 10] As described above, the rotating shaft 10 in each embodiment has a shaft body 12 on which the gear portion 20 and the bearing inner ring portion 31 are arranged side by side in the axial direction. The bearing inner ring portion 31 has an inner ring raceway groove 32 formed on its outer circumferential surface, and a first shoulder portion 33 formed on the outer circumferential surface adjacent to the inner ring raceway groove 32. The tooth grooves 22 of the gear portion 20 extend to the first shoulder portion 33.

[0052] When the rotating shaft 10 of each of the above embodiments rotates, the lubricating oil present in the gear portion 20 is guided along the tooth grooves 22 of the gear portion 20, making it possible to supply the lubricating oil to the inner ring raceway groove 32. The lubricating oil in the inner ring raceway groove 32 adheres to the balls 36 and further to the outer ring raceway groove 38. As a result, it is possible to suppress insufficient lubrication in the bearing portion 30. As shown in FIG. 1 , a transmission 50 includes the rotating shaft 10 of each of the above embodiments and a mating gear 7 that meshes with the gear portion 20 of the rotating shaft 10. By suppressing insufficient lubrication in the bearing portion 30, it is possible to prevent early wear in the bearing portion 30 and prevent the occurrence of seizure.

[0053] [Others] The above-described embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims, not the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims.

[0054] 7 Mating gear 10 Rotating shaft 12 Shaft body 20 Gear portion 22 Tooth groove 31 Bearing inner ring portion 32 Inner ring raceway groove 33 First shoulder portion 35 Outer ring 36 Ball (rolling element) 37 Cage 38 Outer ring raceway groove 39 Pocket 221 End 321 End D1 Outer diameter of shoulder portion D2 Outer diameter of gear portion D3 Outer diameter of tooth groove D4 Outer diameter of tooth groove L Axial distance S Tooth depth dimension W Width dimension of inner ring raceway groove

Claims

1. A rotating shaft having a shaft body on which a gear portion and a bearing inner ring portion are arranged side by side in the axial direction, wherein the bearing inner ring portion has an inner ring raceway groove provided on the outer peripheral surface of the bearing inner ring portion and a shoulder portion provided on the outer peripheral surface adjacent to the inner ring raceway groove, and the tooth grooves of the gear portion extend to the shoulder portion.

2. The rotating shaft according to claim 1, wherein the gear portion is a helical gear.

3. A rotating shaft according to claim 1, wherein the axial distance between the end of the inner ring raceway and the end of the tooth groove located on the shoulder is equal to or less than the width dimension of the inner ring raceway.

4. A rotating shaft according to claim 1, wherein the axial distance between the end of the inner ring raceway groove and the end of the tooth groove located on the shoulder is equal to or less than the tooth height dimension of the gear portion.

5. The rotating shaft according to claim 1, wherein the axial distance between the end of the inner ring raceway groove and the end of the tooth groove located on the shoulder portion is 10 mm or less.

6. A rotating shaft according to any one of claims 1 to 5, wherein the axial distance between the end of the inner ring raceway groove and the end of the tooth groove located on the shoulder portion is greater than zero millimeters.

7. A rotating shaft according to any one of claims 1 to 5, wherein the tooth groove is continuous with the inner ring raceway groove.

8. A rotating shaft according to any one of claims 1 to 5, wherein the outer diameter of the shoulder portion where the tooth grooves are provided is smaller than the outer diameter of the gear portion.

9. The rotating shaft according to claim 8, wherein the outer diameter of the shoulder portion where the tooth grooves are provided is larger than the outer diameter of the tooth root of the gear portion.

10. A rotating shaft according to any one of claims 1 to 5, wherein the outer diameter of the shoulder portion where the tooth grooves are provided is the same as the outer diameter of the gear portion.

11. A rotating shaft according to any one of claims 1 to 5, wherein the outer diameter of the tooth groove provided in the shoulder portion increases toward the inner ring raceway groove side.

12. A rotating shaft as set forth in claim 8, comprising: an outer ring having an outer ring raceway groove facing said inner ring raceway groove; a plurality of rolling elements positioned between said inner ring raceway groove and said outer ring; and an annular cage that holds said plurality of rolling elements, said cage having pockets that house said rolling elements, said pockets opening axially towards said gear portion.

13. A transmission comprising: a rotating shaft according to any one of claims 1 to 5; and a mating gear that meshes with the gear portion of the rotating shaft.

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