JP2012189202A - Planetary gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To favorably lubricate a planetary bearing portion used for an automatic transmission of a vehicle or a reduction differential gear for a vehicle without using a hydraulic pump, to extend the life of the planetary bearing part, and to reduce a friction loss of a pinion part.SOLUTION: An inner ring 33a, an outer ring 33b, and a deep groove ball bearing 33 including balls 33c disposed between the inner ring 33a and the outer ring 33b are arranged around a pinion shaft 31 attached to a carrier 32, so that a pinion gear 29 is rotatably supported by the deep groove ball bearing 33.

Description

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

  Conventionally, needle roller bearings as shown in FIG. 14 are used as planetary bearings used in these planetary gear devices (Patent Documents 1 and 2).

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

  In the pinion shaft 4, a bag hole 6 extending along the axis from the right end surface of FIG. 14, 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.

  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.

  When the pinion gear is a helical gear, if a moment load acts on the bearing and the gradient of the contact surface pressure becomes large, the surface pressure becomes excessively large and the 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.

  In the one disclosed in Patent Document 1, the rollers are arranged in two rows, but the occurrence of local excessive surface pressure is inevitable.

  Moreover, in the thing of patent document 2, although the sliding surface pressure of a washer is reduced, the loss by sliding cannot be eliminated, and it is difficult to supply lubricating oil to a bearing part.

  The problem of such poor lubrication is that it is possible to satisfactorily supply lubricating oil to each part by using a hydraulic pump, but if a hydraulic pump is provided, the device becomes larger and the weight increases accordingly, Since power consumption for operating the hydraulic pump is required, it is not preferable particularly for an electric vehicle that wants to extend the travel distance per charge as much as possible.

  Therefore, the present invention improves the lubrication of the planetary bearing portion used in the automatic transmission of the vehicle and the deceleration differential for the vehicle without using a hydraulic pump, and extends the life of the planetary bearing portion. And it makes it a subject to make the friction loss of a pinion part small.

  In order to solve the above-mentioned problems, the present invention is such that a ball bearing is disposed around a pinion shaft attached to a carrier, and the pinion gear is rotatably supported by the ball bearing.

  A spacer can be disposed 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 increasing the width of the inner ring.

  The pinion gear can use a helical gear, and may be a spur 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 mechanism, edge stress is not generated unlike a needle bearing even when a moment load is applied.

  Moreover, since lubricating oil can be supplied from the width surface of a ball bearing, it is not necessary to supply from a 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 arranging 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 falls down due to moment load, 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 the pinion gear does not contact the carrier even if the pinion gear collapses due to moment load, and there is no torque loss due to sliding contact.

FIG. 1 is a cross-sectional view of a first embodiment of the planetary gear device of the present invention. FIG. 2 is a cross-sectional view of the first embodiment of the planetary gear device of the present invention. FIG. 1 is a cross-sectional view of an embodiment of a reduction differential for an electric vehicle using the planetary gear device of the present invention. 4A is a partially enlarged sectional view of FIG. 3, and FIG. 4B is a partially enlarged sectional view of FIG. 4A. 5 is a cross-sectional view taken along line X1-X1 of FIG. 6A is a front view of the reduction-side sun gear, and FIG. 6B is a cross-sectional view taken along line X2-X2 of FIG. 6A. FIG. 7A is a front view of the deceleration side carrier, and FIG. 7B is a cross-sectional view taken along line X3-X3 in FIG. 7A. 8 is a cross-sectional view taken along line X4-X4 of FIG. FIG. 9A is a front view of the differential-side sun gear, and FIG. 9B is a cross-sectional view taken along line X5-X5 in FIG. 9A. FIG. 10A is a front view of the differential carrier, and FIG. 10B is a cross-sectional view taken along line X6-X6 of FIG. 11A is a front view of the differential-side carrier auxiliary member, and FIG. 11B is a cross-sectional view taken along line X7-X7 in FIG. 9A. FIG. 12 is an exploded cross-sectional view of the main part of an embodiment of a reduction differential for an electric vehicle using the planetary gear device of the present invention. FIG. 13 is an enlarged perspective view showing a part of the gear. It is sectional drawing of the conventional planetary gear apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a 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 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.

  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.

  The outer diameter dimension of the spacer 20 is smaller than the outer diameter dimension of the inner ring 33a, so that lubricating oil is supplied from the width surface of the deep groove ball bearing 33. Therefore, a planetary gear using a conventional needle roller bearing is used. Unlike the apparatus, it is not necessary to provide the pinion shaft 31 with a hole for lubrication connected to the needle bearing, and oil bath lubrication can be used as a lubrication mechanism.

  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. In this embodiment, the spacer 20 arranged between the inner ring 33a and the carrier 32 is omitted in the first embodiment.

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

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

  The electric vehicle speed reduction 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 planetary gear difference arranged in the axial direction coaxial with the speed reducer 12. The moving device 13 and the speed reducer 12 and the oil bath lubrication means 14 common to the differential device 13 are configured.

  The casing 15 that houses these devices is a combination of a motor casing 15a that houses the electric motor 11, a reduction differential casing 15b that houses the speed reducer 12 and the differential device 13, 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. The deceleration differential casing 15b is also open at one end, 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 attached integrally with a core 18 to a motor output shaft 17 on the inner diameter side thereof.

  The motor output shaft 17 is hollow, an outer end portion thereof is supported by an output shaft support bearing 21 interposed between the motor casing 15 a and an inner end portion thereof is inserted into the center of the speed reducer 12. The output shaft support bearing 21 is a deep groove 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 speed reducer input shaft 22 is supported by an input shaft support bearing 23 interposed between the speed reduction differential casing 15b. The input shaft support bearing 23 is also constituted by a deep groove ball bearing.

  The speed reducer 12 has a speed reducing sun gear 27 (see FIG. 5) 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 reducing differential casing 15b on the outer diameter side thereof. The fixed reduction side ring gear 28, a reduction side pinion gear 29 and a reduction side carrier 32 (see FIG. 3) interposed between the sun gear 27 and the ring gear 28 at three substantially circumferential intervals. .

Deceleration side pinion gear 29 meshes with sun gear 27 and ring gear 28. Also,
The pinion gear 29 is supported by a reduction-side pinion shaft 31 via a deep groove ball bearing 33 (see FIG. 5). One end of the pinion shaft 31 is inserted into and supported by the reduction-side carrier 32.

  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

  As shown in FIG. 1, the outer diameter R of the deceleration-side carrier 32 centered on the speed reduction mechanism input shaft 22 is preferably equal to or larger than the maximum diameter R1 of the outer diameter trajectory of the inner ring 33a during the revolution of the pinion gear 29. Set smaller. 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, by setting the outer diameter R of the deceleration side carrier 32 to be equal to or smaller than the maximum diameter R1, lubricating oil by oil bath lubrication (see the white arrow a in FIG. 1) is supplied from the width surface of the bearing. It is avoided that it becomes an obstacle when it is done. In addition, even when it 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 ball 33c.

  The reduction ring gear 28 is positioned and fixed by applying a side surface thereof to a step 34 (see FIG. 3) formed on the inner surface of the reduction differential casing 15b.

  As shown in FIGS. 5 and 6, the speed reduction side 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 speed reducing carrier 32 has a radial clearance h around the input shaft 22 between the closed surface of the speed reducing differential casing 15b facing the open end of the motor casing 15a and the speed reducing pinion gear 29 (see FIG. 4). ). As shown in FIG. 7, the speed reducing 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 of the lubricating oil stored on the inner bottom surface of the speed reducing differential casing 15b. (See FIG. 3).

  Between the central hole 39 of the deceleration side carrier 32 and the outer peripheral edge, three shaft holes 41 through which the pinion shaft 31 is inserted are provided at substantially 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 inserted through the shaft hole 41 is fixed by a pin 44a (see FIG. 4) inserted into the screw hole 43 and a set screw 44b.

  As a means for fixing the pinion shaft 31, a method of fixing a pin (not shown) into the pinion shaft 31 in a radial direction and fixing the pin with a screw screwed into a screw hole, a method of fixing the pinion shaft 31 by crimping, There is a method of fixing the pinion shaft 31 by press-fitting the pinion shaft 31 into the deceleration side carrier 32.

  Three lubricating holes 45 are provided on the PCD between the screw holes 43. 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 differential ring gear 49 and has a function of scooping up the lubricating oil during rotation, and constitutes a part of the oil bath lubricating means 14 described above. .

  Further, a step with a constant width along the periphery of the center hole 39 is formed on the surface of the speed reducing carrier 32 facing the closing surface of the speed reducing differential casing 15b (the radial surface closing the open end of the motor casing 15a). A portion 40 (see FIGS. 4 and 7) is provided, 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 deceleration carrier 32 is received and the deceleration carrier 32 is smoothly rotated.

  In addition, between one end surface of the reduction-side pinion gear 29 in the axial direction and the reduction-side carrier 32 and between the other end surface and the disc portion 49a of the differential-side ring gear 49, respectively, around the pinion shaft 31. A washer 20 is interposed, whereby 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 side than the thrust bearing 47, the lubricating oil is supplied to the bearing 23 by the center hole 39 of the deceleration side carrier 32 and the thrust bearing 47. Care must be taken not to interfere.

  For this reason, 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. 4), 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 components are a differential side ring gear 49, a differential side sun gear 51 provided coaxially on the inner diameter side thereof, and a double pinion type differential side pinion gear interposed between the ring gear 49 and the sun gear 51 and meshing with each other. 52a and 52b are differential side carriers 54 which support the differential side pinion shafts 53a and 53b of these pinion gears 52a and 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.

  It is known in the prior art to adopt a double pinion type in a reduction 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 FIG. 9) of the differential-side sun gear 51 and is serrated. 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 integral therewith, and is connected to the motor casing via an outer end support bearing 57 (see FIG. 3) formed of a deep groove ball bearing. Supported by 15a. The outer end portion of the first output shaft 35 protrudes outside from the motor casing 15a.

  As will be described later, the second output shaft 36 is provided integrally with the first output shaft 35 at the center of the differential carrier 54 and protrudes in the opposite direction to the first output shaft 35.

  The differential ring gear 49 has a disc portion 49a coaxially provided 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 (axial direction). Further, it is bent in the direction in which the second output shaft 36 protrudes, and a peripheral edge 49b is provided. The other end portion of the speed reduction pinion shaft 31 is inserted into and supported by the disk portion 49a, and the convex portion 46 of the speed reduction side carrier 32 is also inserted into the disk portion 49a, thereby connecting the speed reduction side carrier 32 and the differential side ring gear 49. The As a result, the deceleration output resulting from the revolution of the deceleration side pinion gear 29 is transmitted to the differential side ring gear 49.

  Around the shaft hole 55 of the differential sun gear 51, three lubrication holes 56 are provided on the same PCD at substantially equal intervals in the circumferential direction (see FIG. 9). 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 having the same number of teeth and the same size. As shown in FIG. 8, 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. 10, the differential side 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 deep groove ball bearing is interposed between the outer diameter surface of the center boss portion 59 and the casing lid 15c (see FIGS. 3 and 4). The second output shaft support bearing 61 is also a support bearing for the differential 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. 4A, 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 a seal member attached to the opposite surface. This is a deep groove 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.

  An inclined portion 87 having a small diameter on the inner end support bearing 63 side is provided between the serration coupling portion 30 of the first output shaft 35 and the inner end support bearing 63. 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 disc 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. 10). 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, along the outer periphery of the disc part 58, a scooping convex part 66 protruding in the direction facing the inside of the differential 13 is provided between the shaft holes 64a on the large-diameter PCD. A fitting and fixing projection 67 is provided on the tip surface of the convex portion 66.

  The differential carrier 54 has a disk portion 58 interposed between the casing lid 15c and a gear group such as the differential 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. 8). 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 differential side pinion gears 52a and 52b are eight in total, in order to support them stably, the differential side carrier auxiliary member 70 of the annular plate body is different from the disc portion 49a of the differential side ring gear 49. It is interposed between gear groups such as the moving side pinion gears 52a and 52b.

  As shown in FIG. 11, 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 faces the radial direction.

  Radial screw holes 73a and 73b reaching the shaft holes 71a from the outer peripheral surface of the carrier auxiliary member 70 and reaching the shaft holes 71b from the bottom 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 differential side carrier 54 is fitted into the fitting hole 74 and then fixed by welding, so that the carrier auxiliary member 70 is integrated.

  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 set screws 75b screwed from the screw holes 73a and 73b, respectively. . Also in this case, there is a method in which a pin (not shown) is inserted through the pinion shafts 53a and 53b in the radial direction and the pin is fixed by a screw screwed into a screw hole.

  As other fixing methods, there are a method of fixing by crimping the end surfaces of the pinion shafts 53a and 53b, a method of fixing the pinion shafts 53a and 53b by press-fitting the differential side carrier 54 and the carrier auxiliary member 70, and the like.

  The washers 50 are configured so that the pinion gears 52a and 52b rotate smoothly between the outer end surface of each of the differential side pinion gears 52a and 52b and the differential side carrier 54 and between the inner end surface and the carrier auxiliary member 70, respectively. Is interposed.

  Further, a thrust bearing 76 using needle rollers is interposed between the disc portion 58 of the differential side carrier 54 and the differential side sun gear 51 (see FIG. 4). Similarly, a thrust bearing 77 using needle rollers is also interposed between the disc portion 49 a of the differential side ring gear 49 and the differential side 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 differential carrier 54 and the auxiliary member 70 is set so as to reach the oil level accumulated on the inner bottom surface of the deceleration differential casing 15b.

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

  When the electric motor 11 shown in FIG. 3 is driven, the motor output shaft 17 rotates, and at the same time, the reduction gear input shaft 22 integrated with the motor output shaft 17 and the reduction-side sun gear 27 integrated with the input shaft 22 rotate. To do. The reduction-side pinion gear 29 engaged with the reduction-side sun gear 27 revolves while rotating. Due to the revolution, the deceleration side 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 is Zs / (Zs + Zr) when the number of teeth of the reduction-side sun gear 27 is Zs and the number of teeth of the reduction-side ring gear 28 is Zr.

  In the differential device 13, the first output shaft 35 is integrally coupled with the differential-side sun gear 51, and the second output shaft 36 is integrated with the differential-side carrier 54. , 36, the differential sun gear 51, pinion gears 52a and 52b, the carrier 54 and the ring gear 49 rotate together and rotate relative to each other. There is nothing to do. In other words, the input rotation is evenly distributed to the first and second output shafts 35 and 36, and the left and right wheels are rotated 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 is smaller than the input rotational speed Nr of the ring gear 49 by ΔN, the rotational speed of the carrier 54 is increased. 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.

On the other hand, when the load acting on the second output shaft 36 is 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 device 13 will be described with reference to FIG.

  The lubricating oil stored up to the oil level L at a predetermined height on the inner bottom surface of the speed reducing differential casing 15b 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 speed reduction pinion gear 29 provided at three locations on the outer periphery of the speed reduction side carrier 32 pass through the oil below the oil level L of the lubricating oil in the middle of rotation, The lubricating oil is scraped up (see the white arrow in FIG. 12). The scraped up lubricating oil is scattered inside the speed reducer 12 and applied to each component.

  Some of them pass axially through the lubricating hole 45 of the speed reducing carrier 32, its central hole 39, and the lubricating hole 38 of the pinion gear 29 (see the arrow in FIG. 12), or directly without passing through them. The thrust bearing 47, the input shaft support bearing 23, the rolling bearing 33 and the like are supplied.

  In this case, since there is the above-described oil supply gap h, the thrust bearing 47 and the input shaft support bearing 23 are supplied with oil through the gap h in the axial direction.

  A part of the reduction-side pinion gear 29 having a turning radius that extends to the oil level also contributes to the scraping action.

  On the other hand, in the differential device 13, the convex portions 66 provided at the four positions on the outer peripheral portion of the differential side carrier 54, the differential side pinion gears 52a and 52b, and the concave portion 72 of the differential side carrier auxiliary member 70 are lubricated. The oil is scraped up (see the white arrow in FIG. 12).

  The scraped-up lubricating oil 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. 12) or directly supports the second output shaft without passing through them. The bearing 61, thrust bearings 76 and 77 interposed on 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 differential-side sun gear 51 is effective for supplying oil to the thrust bearings 76 and 77 interposed between both end surfaces of the sun gear 51.

  Also in this case, part of the differential-side 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, the reduction gear 12 includes the reduction-side sun gear 27, the pinion gear 29, and the ring gear 28. The differential device 13 includes a differential-side sun gear 51, the same pinion gears 52 a and 52 b, and the same ring gear 49. As shown in FIG. 13, 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.

  For each of the speed reducer 12 and the differential 13, it is effective to improve the lubricity of the gear and to extend the service life by subjecting at least the gear having the smallest diameter to the process of forming countless hollows 83. 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 processing on both, for example, even if the smallest gear is subjected to the above processing to increase its life, if the other gear meshing with it 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 recess 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 Reducer 13 Differential device 14 Oil bath lubrication means 15 Casing 15a Motor casing 15b Deceleration differential casing 15c Casing lid 16 Stator 17 Motor output shaft 18 Core 19 Rotor 20 Spacer 21 Output shaft support bearing 22 Reducer input Shaft 23 Input shaft support bearing 23a Outer ring 23b Inner ring 27 Decreasing side sun gear 28 Decreasing side ring gear 29 Decreasing side pinion gear 30 Serration coupling part 31 Decreasing side pinion shaft 32 Decreasing side carrier 33 Rolling bearing 34 Stepped 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 44a Pin 44b Set screw 45 Lubrication hole 46 Convex portion 47 Thrust bearing 49 Differential side ring Gear 49a Disc portion 49b Peripheral portion 50 Spacer 51 Differential side sun gear 52a, 52b Differential side pinion gear 53a, 53b Differential side pinion shaft 54 Differential side carrier 55 Shaft hole 56 Lubrication hole 57 Outer end support bearing 58 Circle Plate portion 59 Center boss portion 61 Second output shaft support bearing 62 Bearing concave portion 63 Inner end portion support bearing 64a, 64b Shaft hole 65 Lubrication hole 66 Convex portion 67 Fitting fixing protrusion 68a, 68b Needle roller bearing 70 Differential side carrier Auxiliary member 71a, 71b Shaft hole 72 Recess 73a, 73b Screw hole 74 Fitting hole 75a Pin 75b Set screw 76 Thrust bearing 77 Thrust bearing 79 Tooth surface 80 Tooth tip 81 Tooth base 82 Tooth bottom 83 Indent 85 Seal member 86 O Ring 87 inclined part

Claims (12)

  A planetary gear device characterized in that a ball bearing is disposed around a pinion shaft attached to a carrier, and the pinion gear is rotatably supported by the ball bearing.   2. The planetary gear device according to claim 1, wherein a width surface of the pinion gear is not in contact with the carrier.   The planetary gear device according to claim 2, wherein a spacer is disposed 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.   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.   An automatic transmission for a vehicle using the planetary gear device according to claim 1.   The automatic transmission for a vehicle according to claim 6, wherein the lubrication mechanism is oil bath lubrication.   6. A reduction gear differential for an electric vehicle using the planetary gear set according to claim 1.   9. A reduction gear differential for an electric vehicle according to claim 8, wherein the lubrication mechanism is oil bath lubrication.   10. The roughened surface treatment is performed on at least the tooth surface of the gear having the smallest diameter among the gears of the speed reducer that constitutes the vehicle reduction differential device. Reducer differential for electric vehicles.   10. The roughened surface treatment is performed on at least the tooth surface of the gear having the smallest diameter among the gears of the differential gear constituting the vehicle deceleration differential gear. 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 reduction differential for an electric vehicle according to claim 10, wherein

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