WO2013024676A1

WO2013024676A1 - Planetary gear device

Info

Publication number: WO2013024676A1
Application number: PCT/JP2012/068942
Authority: WO
Inventors: 理之冨加見
Original assignee: Ntn株式会社
Priority date: 2011-08-18
Filing date: 2012-07-26
Publication date: 2013-02-21
Also published as: JP2013040665A

Abstract

In order to address the problem of favorably lubricating a pinion gear bearing of a planetary gear device used in a vehicle automatic transmission or a vehicle reduction differential device without using a hydraulic pump, so as to increase the lifespan of the bearing and eliminate the generation of creep between the bearing and the pinion gear, a planetary gear device is constructed such that a deep groove ball bearing (33) is arranged around a pinion shaft (31) attached to a carrier (32), a pinion gear (29) is rotatably supported by the deep groove ball bearing (33), and a positional displacement prevention means is provided between the deep groove ball bearing (33) and the pinion gear (29).

Description

Planetary gear set

The present invention relates to a planetary gear device used in a planetary gear device of an automatic transmission mounted on a vehicle or the like, and a reduction gear differential for a vehicle of an electric vehicle using a motor as a drive source.

Conventionally, needle roller bearings as shown in FIG. 18 have been used as planetary bearings in the planetary gear unit of the above-mentioned device (Patent Documents 1 and 2).

This type of needle roller bearing is composed of a roller 1 and a cage 2 and is disposed around a pinion shaft 4 attached to the carrier 3 and rotatably supports the pinion gear 5.

In the pinion shaft 4, a bag hole 6 extending along the axis from the right end surface of FIG. 18, and extending radially from the middle of the bag hole 6 so as to face the roller on the peripheral surface of the pinion shaft 4. And the lubricating oil is supplied to the roller 1 from the outside of the pinion shaft 4 through the bag hole 6 and the radial hole 7.

Further, a washer 8 is disposed between the carrier 3 and the pinion gear 5.

JP 2007-292152 A JP 2009-216112 A

By the way, since the supply of the lubricating oil to the needle roller bearings constituting the planetary bearing is performed from the hollow bag hole of the pinion shaft through the diameter hole as described above, there is a concern that the lubrication failure is inevitably caused. is there.

Also, when the pinion gear is a helical gear, a moment load acts on the bearing, and when the gradient of the contact surface pressure increases, the surface pressure becomes excessively large and the service life may be shortened.

In particular, when trying to increase the reduction ratio with one stage of the planetary mechanism, the pinion gear has a larger diameter than the width, the moment load applied to the needle roller bearing increases, and the roller edge stress is locally excessive. It tends to be surface pressure.

The one disclosed in Patent Document 1 has two rows of rollers, but local excessive surface pressure is unavoidable.

Further, in Patent Document 2, although the sliding surface pressure of the washer is reduced, loss due to sliding cannot be eliminated, and lubricating oil is difficult to be supplied to the bearing portion.

Such a problem of poor lubrication can be solved temporarily by using a hydraulic pump because the lubricating oil can be satisfactorily supplied to each part. However, if a hydraulic pump is provided, the device will be increased in size and weight will be increased, and power consumption will be required to operate the hydraulic pump. In particular, it is necessary to increase the travel distance per charge as much as possible. It is not preferable for automobiles.

Therefore, the present invention improves the lubrication of the planetary bearing part of the planetary gear unit of the planetary gear unit used in the automatic transmission of the vehicle and the reduction gear differential for the vehicle without using a hydraulic pump. The problem is to extend the life and reduce the friction loss of the pinion part.

In order to solve the above-described problems, the present invention provides a ball bearing disposed around a pinion shaft attached to a carrier, and the pinion gear is rotatably supported by the ball bearing. Position misalignment prevention means is provided.

A spacer can be arranged between the inner ring of the ball bearing and the carrier.

The outer diameter of the spacer is preferably smaller than the outer diameter of the inner ring of the ball bearing.

If the inner ring is fixed by press-fitting it into the pinion shaft, and the carrier is attached with a certain clearance between the inner ring and the pinion gear end face, the carrier can be attached without providing a spacer or increasing the width of the inner ring. It is possible to prevent it from touching. However, there is an inconvenience that requires clearance management at the time of assembly and use. On the other hand, such inconvenience is eliminated by means for providing a spacer or expanding the width of the inner ring.

As the pinion gear, a helical gear can be used, and a spur gear may be used.

As the position deviation prevention means, firstly, a rotation prevention means for preventing position deviation in the rotational direction of the ball bearing and the pinion gear, and secondly, a retaining means for preventing position deviation in the axial direction of the ball bearing and the pinion gear, Thirdly, there is a means that serves as both a retaining means and a rotation preventing means for preventing the positional deviation in both the rotational direction and the axial direction of the ball bearing and the pinion gear.

The planetary gear device of the present invention can be suitably used for an automatic transmission for a vehicle and a reduction differential for an electric vehicle.

Oil bath lubrication can be used as the lubrication mechanism of the planetary gear device of the present invention.

As described above, according to the present invention, by using a ball bearing as a planetary bearing of a planetary gear device, edge stress is not generated unlike a needle bearing even when a moment load is applied.

Also, since the lubricating oil can be supplied from the width surface of the ball bearing, it is not necessary to supply it from the pinion shaft like a needle bearing. In addition, since it is not necessary to provide a hole for lubrication from the pinion shaft to the needle bearing, it can be manufactured at a low cost.

¡By placing a spacer on the inner ring width surface of the ball bearing, the pinion gear does not contact the carrier even if the pinion gear collapses due to moment load or moves in the axial direction, and there is no torque loss due to sliding contact. Further, since the inner ring of the ball bearing does not rotate, the spacer disposed on the width surface does not need to rotate, and although it is in contact with the carrier, there is no torque loss due to sliding contact.

By making the outer diameter of the spacer smaller than the outer diameter of the inner ring of the ball bearing, when the lubricant is to be supplied from the width surface of the ball bearing, the lubricant is smoothly supplied to the balls that are rolling elements. The

Instead of providing a spacer, the width of the inner ring of the ball bearing is made larger than that of the pinion gear, so that even if the pinion gear collapses due to moment load or moves in the axial direction, the pinion gear does not contact the carrier, and torque loss due to sliding contact There is no.

If the ball bearing is simply press-fitted into the inner surface of the pinion gear, there is a concern that creep will cause displacement in the rotational direction and axial direction. However, by providing a positional deviation prevention means between the ball bearing and the pinion gear, It is possible to reliably prevent the occurrence of positional deviation.

In particular, when a configuration in which the outer ring of the ball bearing and the pinion gear are provided in one annular part as a positional deviation prevention means, there is an advantage that the number of parts and assembly man-hours will not increase.

It is a partial cross section figure of 1st Embodiment of a planetary gear apparatus. It is a partial sectional view of a 2nd embodiment similarly. Similarly, it is a partial cross-sectional view of Example 1 of the third embodiment. It is a partial sectional view of Example 2 of the third embodiment. Similarly, it is a partial sectional view of Example 3. FIG. Similarly, it is a partial sectional view of Example 4. FIG. It is sectional drawing of embodiment of the deceleration differential device for electric vehicles which uses a planetary gear apparatus. It is a partially expanded sectional view of FIG. It is a partially expanded sectional view of FIG. 8A. FIG. 8 is a cross-sectional view taken along line X1-X1 of FIG. It is a front view of the sun gear of a reduction gear. FIG. 10B is a sectional view taken along line X2-X2 in FIG. 10A. It is a front view of the carrier of a reduction gear. FIG. 11B is a cross-sectional view taken along line X3-X3 in FIG. 11A. It is sectional drawing of the X4-X4 line | wire of FIG. It is a front view of the sun gear of a differential. It is sectional drawing of the X5-X5 line | wire of FIG. 13A. It is a front view of the carrier of a differential gear. FIG. 14B is a cross-sectional view taken along line X6-X6 of FIG. 14A. It is a front view of the carrier auxiliary member of a differential. FIG. 15B is a cross-sectional view taken along line X7-X7 in FIG. 15A. It is an exploded sectional view of an important section of an embodiment of a reduction differential for electric vehicles which uses a planetary gear device. It is an expansion perspective view which shows a part of gear. It is sectional drawing of the conventional planetary gear apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing the periphery of a pinion shaft in a first embodiment of a planetary gear device according to the present invention.

The planetary gear device of FIG. 1 rotatably supports a pinion gear 29 composed of a helical gear or the like via a deep groove ball bearing 33 around a pinion shaft 31 having one end attached to a carrier 32. . Not only the deep groove ball bearing 33 but also a ball bearing such as an angular ball bearing or a four-point contact ball bearing, that is, a bearing whose rolling element is a ball can be used.

In order to fix the carrier 32 and the pinion shaft 31, a screw 44 screwed in the radial direction from the outer diameter surface of the carrier 32 is pressed against the pinion shaft 31.

As other fixing means, a method of pressing the pin against the pinion shaft and fixing the head of the pin with a set screw, a method of inserting the pin radially into the pinion shaft and fixing the head of the pin with a set screw, a pinion There are a method of caulking and fixing the end surface of the shaft 31, a method of press-fitting the pinion shaft 31 into the carrier 32, and the like.

The other end of the pinion shaft 31 is integrated with a member (a disk portion 49a of a ring gear 49 described later) that transmits a deceleration output to a subsequent device (a differential device 13 described later).

The deep groove ball bearing 33 includes an inner ring 33a, an outer ring 33b, and a ball 33c interposed between the inner ring 33a and the outer ring 33b.

A spacer 20 is disposed between the inner ring 33a and the carrier 32 so that the width surface of the pinion gear 29 and the carrier 32 do not come into contact with each other, and loss due to sliding contact between the width surface of the pinion gear 29 and the carrier 32 is eliminated. A similar spacer 20 is also disposed between the inner ring 33 a and the disc portion 49 a of the ring gear 49. The outer diameter dimension of the spacer 20 is set smaller than the outer diameter dimension of the inner ring 33a.

As shown in FIG. 1, the outer diameter R based on the rotation center of the carrier 32 is preferably set to be equal to or smaller than the maximum diameter R1 of the locus of the outer diameter of the inner ring 33a when the pinion gear 29 revolves. . Even when it is larger than the maximum diameter R1, the size is set so as not to exceed the maximum diameter R2 of the trajectory of the PCD of the ball 33c.

As described above, the spacer 20 is smaller than the outer diameter of the inner ring 33a, and the outer diameter R of the carrier 32 is set equal to or smaller than the maximum diameter R1, so that the lubricating oil by oil bath lubrication (FIG. 1) is obtained. It is possible to avoid an obstacle when the white arrow a) is supplied from the width surface of the bearing. Even when the outer diameter R is larger than the maximum diameter R1, it is desirable to set the size so as not to exceed the maximum diameter R2 of the trajectory of the PCD of the ball 33c.

With the above configuration, there is no need to provide a hole for lubrication connected to the needle bearing in the pinion shaft 31 as in a planetary gear device using a conventional needle roller bearing, and oil bath lubrication is used as a lubrication mechanism. can do.

As an example of the planetary gear device in the first embodiment, the second embodiment and the third embodiment described below, the planetary gear reduction in the later-described electric vehicle reduction differential (see FIGS. 7 to 18). Machine 12 can be mentioned.

FIG. 2 shows a second embodiment of the present invention. In the second embodiment, the width of the inner ring 33a is made larger than the width of the pinion gear 29 so that the carrier 32 is not contacted even if the pinion gear 29 is tilted. Further, since the spacer 20 used in the first embodiment is not necessary, it is omitted.

3 to 6 show Examples 1 to 4 of the third embodiment of the present invention. In any of these, in addition to the configuration of FIG. 1 (first embodiment) described above, a misalignment prevention means 88 between the outer ring 33b of the deep groove ball bearing 33 and the pinion gear 29 is added. Similar misalignment prevention means can be added to FIG. 2 (second embodiment).

In the case of the first and second embodiments, the outer ring 33b of the deep groove ball bearing 33 is press-fitted into the inner surface of the pinion gear 29, so that the outer ring 33b and the pinion gear 29 rotate together.

However, when the tightening allowance between the two is insufficient, there is a possibility that positional deviation in the rotational direction or the axial direction may occur due to creep or the like generated between the pinion gear 29 and the outer ring 33b when the pinion gear 29 rotates under load. In the third embodiment, in order to prevent such a positional deviation, a positional deviation prevention means 88 is provided between the outer ring 33 b and the pinion gear 29.

3 (Example 1 of the third embodiment), the misalignment prevention means 88 prevents rotation of the deep groove ball bearing 33 and the pinion gear 29 in the rotational direction, and prevents misalignment in the axial direction. It is comprised by the retaining means to do. The retaining means may be omitted.

In the configuration of the above-described rotation preventing means, the pin 89 is raised on the outer diameter surface of the outer ring 33 b, while the engagement concave portion 90 is provided on the end surface of the pinion gear 29, and the pinion gear 29 is fitted in the axial direction. It is the structure to engage.

The configuration of the retaining means is a configuration in which a retaining ring 92 formed by an elastic split ring is fitted into a circumferential groove 91 provided on the outer diameter surface of the outer ring 33b, while an engaging groove 93 is provided on the inner circumferential surface of the pinion gear 29. It is. When the pinion gear 29 is fitted to the outer diameter surface of the outer ring 33b from the axial direction while the retaining ring 92 is reduced in diameter, and further advanced to engage the engaging recess 90 with the pin 89, the retaining ring 92 is restored by its restoring action. The part is engaged with the engaging groove 93.

4 (same example 2) is provided with a pin hole 94 that penetrates the pinion gear 29 in the radial direction and reaches the outer ring 33b, and presses the pin 95 into the pin hole 94 portion of the outer ring 33b. . The tip of the pin 95 is left in the pin hole 94 portion of the pinion gear 29. In this case, the anti-rotation function and the retaining function are performed at the same time.

In the case of FIG. 4, the misalignment prevention means 88 in FIG. 5 (same example 3) prevents the pin 95 from coming off by screwing a set screw 96 reaching the pin 95 from the end face of the pinion gear 29 in the axial direction. ing. Since the pin 95 is prevented from slipping out, the pin 95 can be more reliably prevented from rotating. Also in this case, the anti-rotation function and the retaining function are performed at the same time. In this case, the pin 95 may not be press-fitted.

The misalignment prevention means 88 of FIG. 6 (same example 4) takes into account that parts such as the pin 89 are necessary in each of the cases of FIGS. 3 to 5 and that the number of assembly steps for incorporating them increases. In this case, the outer ring 33 b and the pinion gear 29 are constituted by one annular part 97. By providing the rolling groove 98 on the inner diameter surface of the annular part 97, the inner diameter portion becomes the outer ring 33b, and by providing the tooth profile 99 on the outer diameter surface, the outer diameter portion becomes the pinion gear 29. Since there is no fitting portion between the outer ring 33b and the pinion gear 29, creep does not occur. Also in this case, the anti-rotation function and the retaining function are performed at the same time.

4 (example 2 of the third embodiment) to FIG. 6 (same example 4) as described above, each of the misalignment prevention means 88 exhibits a detent function and a retaining function. It can also be said that it is a retaining means. In addition, since both functions are exhibited at the same time, it can be said that the rotation preventing means also serves as the retaining means (conversely, the retaining means also serves as the retaining means).

The planetary gear device of the present invention can be suitably used for an automatic transmission for a vehicle and a deceleration differential device for a vehicle.

Hereinafter, a reduction gear differential for an electric vehicle using the planetary gear device of the present invention will be described.

As shown in FIG. 7, the electric vehicle deceleration differential device includes an electric motor 11, a planetary gear speed reducer 12 arranged in the axial direction coaxially with the electric motor 11, and a shaft coaxial with the speed reducer 12. The planetary gear differential 13 arranged in the direction, the speed reducer 12 and the oil bath lubrication means 14 common to the differential 13 are configured.

The casing 15 in which these devices are stored is a combination of a motor casing 15a in which the electric motor 11 is stored, a reduction differential casing 15b in which the reduction gear 12 and the differential device 13 are stored, and a casing lid 15c. One end portion of the motor casing 15a is opened, and the open end is closed by the deceleration differential casing 15b. One end of the deceleration differential casing 15b is also opened, and the open end is closed by a casing lid 15c.

The electric motor 11 includes a stator 16 fixed to the inner peripheral surface of the motor casing 15a, and a rotor 19 integrally attached to a motor output shaft 17 and a core 18 on the inner diameter side thereof.

The motor output shaft 17 is hollow, and its outer end (left end in FIG. 7) is supported by an output shaft support bearing 21 interposed between the motor casing 15a and the inner end (same right end) is It is inserted into the center of the speed reducer 12. The output shaft support bearing 21 is a ball bearing with a seal. A portion of the motor output shaft 17 inserted into the speed reducer 12 is a speed reducer input shaft 22.

The portion of the speed reducer input shaft 22 is supported by an input shaft support bearing 23 interposed between the speed reducer differential casing 15b. The input shaft support bearing 23 is also constituted by a ball bearing.

As shown in FIG. 9, the speed reducer 12 has a sun gear 27 integrally provided on the outer peripheral surface of the tip of the speed reducer input shaft 22, and is coaxial with the inner diameter surface of the speed reduction differential casing 15b on the outer diameter side thereof. The ring gear 28 is fixed to the ring gear 28, and the pinion gear 29 and the carrier 32 (see FIG. 11) are provided at three intervals in the circumferential direction between the sun gear 27 and the ring gear 28.

The pinion gear 29 meshes with the sun gear 27 and the ring gear 28. The pinion gear 29 is supported on the pinion shaft 31 of the first embodiment described above via a deep groove ball bearing 33 (see FIG. 9), and one end of the pinion shaft 31 is attached to the carrier 32.

As described above, the deep groove ball bearing 33 includes an inner ring 33a, an outer ring 33b, a ball 33c interposed between the inner ring 33a and the outer ring 33b, and a cage. Illustration of cage is omitted

The ring gear 28 is positioned and fixed by applying a side surface thereof to a step portion 34 (see FIG. 8A) formed on the inner surface of the reduction differential casing 15b.

9 and 10, the pinion gear 29 is provided with a shaft hole 37 into which the pinion shaft 31 is inserted via the deep groove ball bearing 33.

The carrier 32 has a radial clearance h (see FIG. 8A) around the input shaft 22 between the closed surface of the reduction differential casing 15b facing the open end of the motor casing 15a and the pinion gear 29. Mated. As shown in FIG. 11, the carrier 32 is formed by an annular plate having a constant center hole 39, and the radius of rotation thereof is the oil level L (see FIG. 5) of the lubricating oil stored on the inner bottom surface of the speed-reducing differential casing 15b. 7)).

Between the center hole 39 and the outer peripheral edge of the carrier 32, three shaft holes 41 through which the pinion shaft 31 is inserted are provided at equal intervals on the same PCD. A notch surface 42 perpendicular to the radial direction is formed on the outer peripheral edge of each shaft hole 41 in the radial direction, and a screw hole 43 reaching the shaft hole 41 from the notch surface 42 is provided in the radial direction. The pinion shaft 31 is inserted into the shaft hole 41, and a screw 44 is screwed into the screw hole 43 to fix the carrier 32 and the pinion shaft 31 (see FIGS. 1 to 6 and 8A). As described above, there are other fixing means.

Three lubrication holes 45 are provided on the PCD between the shaft holes 41. Each lubricating hole 45 is formed by a long hole curved in the circumferential direction. Further, at three locations facing the outer diameter side of each lubrication hole 45, convex portions 46 are respectively provided outward from the outer peripheral edge in the axial direction (in the direction of the differential device 13). As will be described later, the convex portion 46 is coupled to the ring gear 49 of the differential device 13 and has a function of scooping up the lubricating oil during rotation. Constitute.

Further, a stepped portion 40 having a constant width along the periphery of the center hole 39 is formed on the surface of the carrier 32 facing the closing surface of the deceleration differential casing 15b (the radial surface closing the open end of the motor casing 15a). (See FIGS. 8A and 11), and a thrust bearing 47 using needle rollers is attached to the stepped portion 40. The thrust bearing 47 is brought into contact with the closing surface of the deceleration differential casing 15b, so that the thrust force acting on the carrier 32 is received and the carrier 32 is smoothly rotated.

A spacer 20 is interposed around the pinion shaft 31 between one end face in the axial direction of the pinion gear 29 and the carrier 32 and between the other end face and the disk portion 49a of the ring gear 49, respectively. Thereby, the pinion gear 29 is smoothly rotated.

Since the input shaft support bearing 23 is provided at a position closer to the electric motor 11 than the thrust bearing 47, the center hole 39 of the carrier 32 and the thrust bearing 47 prevent the supply of lubricating oil to the bearing 23. You must be careful not to have any.

Therefore, in this embodiment, it is necessary to set the inner diameter of the carrier 32 and the inner diameter of the thrust bearing 47 to be larger than the outer diameter of the inner ring 23 b constituting the input shaft support bearing 23. In order to satisfy this condition, in the illustrated case (see FIG. 8A), the inner diameter of the carrier 32 and the inner diameter of the thrust bearing 47 are set to be equal to or larger than the inner diameter of the outer ring 23a of the bearing 23. The clearance h is secured.

Next, the differential device 13 will be described. The differential device 13 is provided coaxially with the speed reducer 12 inside the speed reduction differential casing 15b. The constituent members include a ring gear 49, a sun gear 51 coaxially provided on the inner diameter side thereof, double pinion type pinion gears 52a and 52b interposed between the ring gear 49 and the sun gear 51, and these pinion gears 52a, The carrier 54 supports the

pinion shafts

53a and 53b of the 52b.

In the figure, eight

pinion gears

52a and 52b are used in total, but six may be used. The number of pinion gears 29 of the reduction gear 11 is not limited.

Note that it is conventionally known that a double pinion type is adopted in a deceleration differential for an electric vehicle (see Japanese Patent Application Laid-Open No. 7-323741).

The inner end of the first output shaft 35 passes through the shaft hole 55 (see FIGS. 7, 8, and 13) of the sun gear 51 and is coupled to the sun gear 51 by the serration coupling portion 30. The outer end portion of the first output shaft 35 is penetrated by the speed reducer input shaft 22 and the motor output shaft 17 integrated therewith, and is connected to the motor casing 15a via an outer end support bearing 57 (see FIG. 7) formed of a ball bearing. Supported by. The outer end portion of the first output shaft 35 protrudes from the motor casing 15a to the outside (left side in FIG. 7).

As will be described later, the second output shaft 36 is provided integrally with the first output shaft 35 at the center of the carrier 54 and is opposite to the first output shaft 35 (right side in FIGS. 7 and 8). Sticks out.

The ring gear 49 has a disc portion 49a provided coaxially on the outer periphery of the first output shaft 35 with a radial gap, and an outer peripheral edge of the disc portion 49a outward (in the axial direction and the second direction). The outer peripheral portion 49b is provided by being bent in the direction in which the output shaft 36 protrudes. The other end portion of the pinion shaft 31 on the speed reducer 12 side is inserted and supported on the disc portion 49a, and the convex portion 46 of the carrier 32 is also inserted into the disc portion 49a (see FIG. 7). The carrier 32 and the ring gear 49 on the differential device 13 side are connected. As a result, the deceleration output resulting from the revolution of the pinion gear 29 of the speed reducer 12 is transmitted to the ring gear 49 of the differential device 13.

Around the shaft hole 55 of the sun gear 51, three lubricating holes 56 are provided on the same PCD at substantially equal intervals in the circumferential direction (see FIG. 13). The lubricating hole 56 is also a long hole curved in the circumferential direction.

The double pinion type pinion gears 52a and 52b are gears of the same size with the same number of teeth. As shown in FIG. 12, one pinion gear 52a has a larger PCD than the other pinion gear 52b. The pinion gear 52b with the smaller PCD meshes with the sun gear 51.

As shown in FIG. 14, the carrier 54 is provided with a center boss portion 59 at the center of the outer surface of the disc portion 58. The second output shaft 36 is provided on the outer end surface of the center boss portion 59 so as to protrude outward in a coaxial state, and a bearing recess 62 opened inward is provided inside the center boss portion 59.

A second output shaft support bearing 61 formed of a ball bearing is interposed between the outer diameter surface of the center boss portion 59 and the casing lid 15c (see FIGS. 7 and 8). The second output shaft support bearing 61 is also a support bearing for the carrier 54. Further, the inner end portion of the first output shaft 35 is inserted into the bearing recess 62, and the inner end portion is supported so as to be relatively rotatable via an inner end portion support bearing 63 formed of a needle roller bearing.

As shown in FIG. 8B, the second output shaft support bearing 61 has a seal member 85 attached to the end facing the outside of the casing lid 15c, and no seal member attached to the opposite surface. This is a ball bearing with a so-called one-side seal. Further, an O-ring 86 is interposed between the outer ring and the casing lid 15c so as to seal the portion. As a result, the bearing also serves as a sealing function, and the length in the width direction can be reduced.

Between the serration coupling portion 30 of the first output shaft 35 and the inner end support bearing 63, an inclined portion 87 having a small diameter on the inner end support bearing 63 side is provided. The inclined portion 87 has a function of guiding the lubricating oil dropped between the serration coupling portion 30 and the inner end support bearing 63 to the inner end support bearing 63 side.

The inner end support bearing 63 is constituted by, for example, a shell needle roller bearing. Since this bearing has flanges bent toward the inner diameter side on both side edges of the outer ring, lubricating oil can be stored inside thereof.

The disk portion 58 is provided with

shaft holes

64a and 64b on a certain PCD corresponding to the positions of the

pinion shafts

53a and 53b (see FIG. 14A). Further, between the small-diameter PCD and the center boss portion 59, lubricating holes 65 are provided at substantially equal intervals in four locations in the circumferential direction. These lubricating holes 65 are also formed by curved long holes.

Further, a scooping convex portion 66 protruding in the direction facing the inside of the differential 13 is provided between the shaft holes 64a on the large-diameter PCD along the outer periphery of the disc portion 58. A fitting and fixing projection 67 is provided on the tip surface of the convex portion 66.

The disk 54 of the carrier 54 is interposed between the casing lid 15c and a gear group such as the pinion gears 52a and 52b. The

pinion shafts

53a and 53b are inserted into the pinion gears 52a and 52b via double-row

needle roller bearings

68a and 68b (see FIG. 12). The outer ends of the

pinion shafts

53a and 53b are inserted into and supported by the shaft holes 64a and 64b of the carrier 54, respectively.

Since the total number of pinion gears 52a and 52b is eight, in order to support them stably, the carrier auxiliary member 70 of the annular plate member is provided between the disc portion 49a of the ring gear 49 and the gear group such as the pinion gears 52a and 52b. Intervened in.

As shown in FIG. 15, the carrier auxiliary member 70 is provided with a pair of

shaft holes

71a and 71b having different PCDs at positions corresponding to the

pinion shafts

53a and 53b. Scraping recesses 72 are provided at four locations on the entire circumference on the outer peripheral edge of the shaft hole 71b on the small-diameter PCD that is radially opposed to the shaft hole 71b.

The screw holes 73a and 73b in the radial direction reaching the shaft holes 71a from the outer peripheral surface of the carrier auxiliary member 70 and reaching the shaft holes 71b from the bottoms of the recesses 72 are provided. Further, four fitting holes 74 formed as long holes are formed in the circumferential direction of the shaft hole 71a on the large-diameter PCD. The fitting fixing protrusion 67 of the carrier 54 is fitted into the fitting hole 74 and then fixed by welding to achieve integration with the carrier auxiliary member 70.

The inner ends of the

pinion shafts

53a and 53b are inserted into the shaft holes 71a and 71b, respectively, and the

pinion shafts

53a and 53b are fixed to the carrier auxiliary member 70 by screws 75 screwed from the screw holes 73a and 73b, respectively. In this case, there is also a method in which a pin (not shown) is inserted in the

pinion shafts

53a and 53b in the radial direction and fixed by a set screw 96 screwed into the screw hole.

A spacer 50 is interposed between the outer end surface of each

pinion gear

52a, 52b and the carrier 54 and between the inner end surface and the carrier auxiliary member 70 so that the pinion gears 52a, 52b rotate smoothly. *

Further, a thrust bearing 76 using needle rollers is interposed between the disc portion 58 of the carrier 54 and the sun gear 51 (see FIG. 8A). Similarly, a thrust bearing 77 using needle rollers is interposed between the disc portion 49 a of the ring gear 49 and the sun gear 51. These

thrust bearings

76 and 77 are both arranged on the inner diameter side of the lubrication hole 56 of the sun gear 51.

It should be noted that at least one of the rotation radii of the carrier 54 and the auxiliary member 70 is set so as to reach the oil level L stored on the inner bottom surface of the deceleration differential casing 15b.

The electric vehicle deceleration differential is configured as described above, and the operation thereof will be described next.

When the electric motor 11 shown in FIG. 7 is driven, the motor output shaft 17 rotates, and at the same time, the reduction gear input shaft 22 integral with the motor output shaft 17 and the sun gear 27 of the reduction gear 12 integral with the input shaft 22. Rotates. The pinion gear 29 meshed with the sun gear 27 revolves while rotating. By the revolution, the carrier 32 is decelerated and rotated, and the decelerated rotation is output to the differential device 13 side.

As is well known, the reduction ratio when the number of teeth of the sun gear 27 is Zs and the number of teeth of the ring gear 28 is Zr is Zs / (Zs + Zr).

In the differential 13, the first output shaft 35 is integrally coupled with the sun gear 51, and the second output shaft 36 is integrated with the carrier 54, so that the differential output 13 is attached to each of these

output shafts

35, 36. When the loads acting on the left and right wheels (not shown) are equal, the sun gear 51, the pinion gears 52a and 52b, the carrier 54, and the ring gear 49 rotate together and do not rotate relative to each other. In other words, the input rotation is evenly distributed to the first and

second output shafts

35 and 36 to rotate the left and right wheels at a constant speed.

On the other hand, when a difference occurs in the load acting on the left and right wheels, the input rotation is differentially distributed to the first and

second output shafts

35 and 36 according to the load difference due to the rotation and revolution of the pinion gears 52a and 52b. Is done.

That is, when the load acting on the first output shaft 35 becomes relatively large and the rotational speed Ns of the sun gear 51 integrated therewith becomes smaller by ΔN than the input rotational speed Nr of the ring gear 49, the rotational speed of the carrier 54. Nc is
Nc = Nr + λ / (1-λ) · ΔN
Thus, the speed of the second output shaft 36 is increased. Where λ is the gear ratio (= Zs / Zr), Zs is the number of teeth of the sun gear 51, and Zr is the number of teeth of the ring gear 49.

Conversely, when the load acting on the second output shaft 36 becomes relatively large and the rotation speed Nc of the carrier 54 integrated therewith is smaller than the input rotation speed Nr by ΔN, the rotation speed Ns of the sun gear 51 is ,
Ns = Nr + (1-λ) / λ · ΔN
Thus, the first output shaft 35 is accelerated.

Next, the lubricating action of the speed reducer 12 and the differential 13 will be described with reference to FIG.

The lubricating oil stored up to the oil level L having a predetermined height on the inner bottom surface of the speed-reducing differential casing 15 b is commonly used for oil bath lubrication of the speed reducer 12 and the differential device 13.

In the speed reducer 12, the convex portions 46 and the pinion gear 29 provided at three locations on the outer peripheral portion of the carrier 32 pass through the oil below the oil level L of the lubricating oil during the rotation, so that the lubricating oil is scraped. The raising action is performed (see the white arrow in FIG. 16). The scraped up lubricating oil is scattered inside the speed reducer 12 and applied to each component.

A part of them passes through the lubrication hole 45 and the center hole 39 of the carrier 32 in the axial direction (see the arrow in FIG. 16) or directly without passing through these, the thrust bearing 47, the input shaft support bearing. 23, supplied to the rolling bearing 33 and the like.

In this case, since there is the aforementioned oil supply gap h, oil is supplied to the thrust bearing 47 and the input shaft support bearing 23 through the gap h in the axial direction.

It should be noted that a part of the pinion gear 29 having a turning radius that extends to the oil surface also contributes to the scraping action.

On the other hand, in the differential device 13, the convex portions 66, the pinion gears 52a and 52b, and the concave portion 72 of the carrier auxiliary member 70 provided at four locations on the outer peripheral portion of the carrier 54 respectively perform a scooping action of the lubricating oil (see FIG. (See 16 open arrows).

The lubricating oil thus scraped passes through the lubricating hole 65 of the carrier 54 and the lubricating hole 56 of the sun gear 51 in the axial direction (see the arrow in FIG. 16) or directly supports the second output shaft without passing through them. The bearing 61,

thrust bearings

76 and 77 interposed between both end surfaces of the sun gear 51, and double row

needle roller bearings

68a and 68b of the double pinion gears 52a and 52b are supplied.

The lubrication hole 56 of the sun gear 51 is effective for supplying oil to the

thrust bearings

76 and 77 interposed at both end surfaces of the sun gear 51.

In this case as well, part of the pinion gears 52a and 52b having a turning radius that extends to the oil surface also contributes to the scraping action.

The electric vehicle deceleration differential according to the above embodiment employs oil bath lubrication. By further improving the lubricity of the gear tooth surface in this oil bath lubrication, the durability of the gear is further improved.

That is, as the target gears, in the speed reducer 12, there are a sun gear 27, a pinion gear 29, and a ring gear 28. The differential device 13 includes a sun gear 51, pinion gears 52 a and 52 b, and the ring gear 49. As shown in FIG. 17, innumerable minute depressions 83 are randomly provided in the tooth tip portion 80, the tooth portion 81, and the tooth bottom portion 82 that form the tooth surface 79 of these gears.

The surface roughness parameters of the tooth surface 79 are as follows: Ryni is 2.0 to 5.5 μm, Rymax is 2.5 to 7.0 μm, Rqni is 0.3 to 1.1 μm, and Rsk is 1.6 or less.

Since the minute recess 83 becomes an oil reservoir, sufficient durability can be maintained even in the case of oil bath lubrication. As a result, the gear itself can be reduced in size and the entire apparatus can be reduced in size.

For each of the speed reducer 12 and the differential 13, it is effective to improve the lubricity of the gear and extend the life by processing the infinite number of the minute depressions 83 on at least the gear having the smallest diameter. is there. In some cases, both the sun gear 27 and the pinion gear 29 in the reduction gear 12 and the sun gear 51 and the pinion gears 52a and 52b in the differential device 13 may need to be processed. It is necessary to perform the processing on both, for example, even if the smallest gear is subjected to the above processing to increase the life, if the other gear meshing with this has a short life, an unbalance occurs in both the life Because.

In order to form the minute recesses 83 at random, the tooth surface 79 is smoothed by gyro polishing, barrel polishing or the like, and then a recess forming means is applied to the smoothed tooth surface. In this case, the dent formation means is performed by a method in which fine hard particles mainly composed of aluminum oxide or the like are collided by shot peening, liquid honing, or the like.

DESCRIPTION OF SYMBOLS 11 Electric motor 12 Reduction gear 13 Differential device 14 Oil bath lubrication means 15 Casing 15a Motor casing 15b Reduction differential casing 15c Casing lid 16 Stator 17 Motor output shaft 18 Core 19 Rotor 20 Spacer 21 Output shaft support bearing 22 Reduction gear input Shaft 23 Input shaft support bearing 23a Outer ring 23b Inner ring 27 Sun gear 28 Ring gear 29 Pinion gear 30 Serration coupling part 31 Pinion shaft 32 Carrier 33 Deep groove ball bearing 33a Inner ring 33b Outer ring 33c Ball 34 Step part 35 First output shaft 36 Second output shaft 37 Shaft Hole 39 Center hole 40 Stepped portion 41 Shaft hole 42 Notched surface 43 Screw hole 44 Screw 45 Lubrication hole 46 Convex portion 47 Thrust bearing 49 Ring gear 49a Disc portion 4 b Peripheral portion 50 Spacer 51 Sun gear 52a, 52b Pinion gear 53a, 53b Pinion shaft 54 Carrier 55 Shaft hole 56 Lubrication hole 57 Outer end support bearing 58 Disc portion 59 Center boss portion 61 Second output shaft support bearing 62 Bearing recess 63 Inner end support bearings 64a, 64b Shaft hole 65 Lubrication hole 66 Protruding part 67 Fitting fixing protrusion 68a, 68b Needle roller bearing 70 Carrier auxiliary member 71a, 71b Shaft hole 72 Recessed part 73a, 73b Screw hole 74 Fitting hole 75 Screw 76 Thrust bearing 77 Thrust bearing 79 Tooth surface 80 Tooth tip 81 Tooth portion 82 Tooth bottom 83 Indentation 85 Seal member 86 O-ring 87 Inclined portion 88 Non-rotating means 89 Pin 90 Engaging recess 91 Circumferential groove 92 Retaining ring 93 Engagement Groove 94 pin hole 95 pin 96 G 97 Annular part 98 Rolling groove 99 Tooth profile

Claims

A planetary gear comprising a ball bearing arranged around a pinion shaft attached to a carrier, the pinion gear rotatably supported by the ball bearing, and a mutual displacement preventing means provided between the ball bearing and the pinion gear. Gear device.
The planetary gear device according to claim 1, wherein a width surface of the pinion gear is prevented from contacting a carrier.
The planetary gear device according to claim 2, wherein a spacer is arranged between the inner ring of the ball bearing and the carrier.
4. The planetary gear device according to claim 3, wherein the outer diameter of the spacer is smaller than the outer diameter of the inner ring of the ball bearing.
3. The planetary gear device according to claim 2, wherein the width of the inner ring of the ball bearing is larger than the width of the pinion gear.
The planetary gear device according to any one of claims 1 to 5, wherein the positional deviation preventing means is constituted by mutual rotation preventing means of the ball bearing and the pinion gear.
7. The anti-rotation means has a configuration in which an outer ring and a pinion gear of a ball bearing are constituted by one annular part, an outer ring is provided on an inner diameter part of the annular part, and a pinion gear is provided on an outer diameter part. The planetary gear device described in 1.
The planetary gear device according to any one of claims 1 to 5, wherein the positional deviation prevention means includes a mutual rotation prevention means and a slip prevention prevention means of the ball bearing and the pinion gear.
The planetary gear device according to any one of claims 1 to 5, wherein the positional deviation prevention means is constituted by a rotation preventing means that also serves as a prevention means for preventing the ball bearing and the pinion gear from coming off each other.
The anti-rotation means that also serves as the retaining means is configured such that the outer ring of the ball bearing and the pinion gear are configured by one annular part, and the outer ring is provided on the inner diameter part of the annular part, and the pinion gear is provided on the outer diameter part. The planetary gear device according to claim 9, wherein
An automatic transmission for a vehicle using the planetary gear device according to any one of claims 1 to 10.
The automatic transmission for vehicles according to claim 11, wherein the lubrication mechanism is oil bath lubrication.
A reduction differential for an electric vehicle using the planetary gear device according to any one of claims 1 to 10.
The electric vehicle deceleration differential according to claim 13, wherein the lubrication mechanism is oil bath lubrication.
15. The roughened surface of the gear surface of the gear having the smallest diameter among the gears of the speed reducer or the differential gear constituting the vehicle speed reduction differential device is provided according to claim 13 or 14. Reducer differential for electric vehicles.
The surface roughness parameters of the tooth surface by the rough surface processing are as follows: Ryni is 2.0 to 5.5 μm, Rymax is 2.5 to 7.0 μm, Rqni is 0.3 to 1.1 μm, and Rsk is 1.6 or less. The deceleration differential for an electric vehicle according to claim 15, wherein: