JP2012031934A - Reduction differential gear for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction differential gear for an electric vehicle comprising a planetary gear type reduction gear and a differential gear, wherein lubricating oil can be sufficiently distributed to respective parts in the gear and no special component is required to be added as a scratching-up means while increasing a traveling distance per charge by realizing the reduction in size and weight by employing an oil-bath lubrication as a lubrication means.SOLUTION: A reduction differential gear for an electric vehicle is formed through the combination of an electric motor 11, a planetary gear type reduction gear 12, a differential gear 13 and a lubrication means 14, and employs an oil bath lubrication as the lubrication means 14, wherein rotational radii of respective carriers 32, 54 of the reduction gear 12 and differential gear 13 are formed to be not more than an oil level. Scratching-up protrusions 46 are provided to outer peripheral surfaces of respective carriers 32, 54.

Description

  The present invention relates to a deceleration differential device for an electric vehicle using a motor as a drive source, and is particularly characterized in that it is reduced in size and weight, thereby reducing restrictions on layout and extending a travel distance per charge.

  Conventionally known reduction gear differentials for automobiles are constituted by a combination of an electric motor, a planetary gear type reduction gear, a planetary gear type differential device, and lubricating means. The speed reducer includes an input shaft that is integrated with an output shaft of the electric motor, and the differential device includes a 2-output shaft that receives the speed reduction output of the speed reducer as an input and is coaxially opposed. The two output shafts are configured to distribute and output the rotation corresponding to the difference in load acting on the left and right wheels (Patent Documents 1 and 2).

  In the electric vehicle, the reduction gear is provided because the electric motor is reduced in size and weight and rotates at a high speed, so that it is necessary to reduce the speed and transmit it to the wheels. The planetary gear mechanism is used for the differential device because the axial length is smaller than that of the bevel gear type and the entire device can be downsized. Further, in order to reduce the size, a structure is adopted in which one of the two output shafts provided in the differential device passes through the inside of the speed reducer input shaft and the motor output shaft.

  In addition, it is conventionally known that a hydraulic pump and an electric motor for driving the hydraulic pump are provided as lubrication means of the deceleration differential device (Patent Document 3). Also, in the case of oil bath lubrication, where the amount of lubricating oil supplied is limited, in order to improve the durability of the gear, it is easy to form an oil film by roughening the tooth surfaces of a large number of gears constituting the device. It is also known to do (Patent Document 4).

JP-A-8-42656 Japanese Patent Laid-Open No. 7-323741 JP-A-11-190417 JP 2009-127842 A

  Needless to say, if the hydraulic pump as described above is used as the lubrication means, the lubricating oil can be sufficiently supplied to the necessary portions. However, if the hydraulic pump is used, there is a problem that the apparatus becomes larger and the weight increases by the volume. is there. In addition, since the electric motor that drives the hydraulic pump consumes electric power, it is an undesirable problem for an electric vehicle that wants to extend the travel distance per charge as much as possible.

  For this reason, by adopting oil bath lubrication (so-called splash-type lubrication) as an alternative to the hydraulic pump, the size and weight of the device can be reduced, layout restrictions can be reduced, and travel per charge can be achieved. It may be possible to increase the distance.

  However, in the case of oil bath lubrication, the lubricant that has been scraped up by the scraping means is simply splashed, so there is a problem that it is difficult to sufficiently distribute the lubricant to all bearings and gears that require lubrication. is there.

  Therefore, the present invention adopts oil bath lubrication as the above-mentioned lubricating means to reduce the size and weight of the apparatus, reduce the restrictions on the layout, extend the travel distance per charge, In both apparatuses, it is an object to realize oil bath lubrication that does not require the addition of special parts as a scraping means.

  Further, when the above-described oil bath lubrication is employed, another object is to sufficiently distribute the lubricating oil to necessary portions.

  In order to solve the above-mentioned problems, the present invention comprises a combination of an electric motor, a planetary gear type reduction gear, a planetary gear type differential device and a lubricating means, and the reduction gear includes a motor output shaft of the electric motor. An integrated reduction gear input shaft is provided, and the differential device has a reduction output of the reduction gear as an input, and has two output shafts opposed on the same axis, and distributes differential rotation to the two output shafts. In the reduction differential for an electric vehicle, wherein the oil bath lubrication is adopted as the lubricating means, and the oil bath lubrication supplies the lubricating oil to the movable parts of the reduction gear and the differential. The rotating radius of at least one of the speed reduction carrier and the differential carrier, which is a component of the machine and the differential gear, is formed to a size that is equal to or less than the oil level of the lubricating oil accumulated at the bottom of the machine. Means scooped constituted by projections or recesses on the outer peripheral surface of each carrier is obtained by adopting a configuration in which is provided.

  The reduction-side carrier and the differential-side carrier are essential members for the planetary gear mechanism that constitutes the reduction gear and the differential device, respectively. The rotational radius of these carriers can be set as described above, and the lubricating oil can be scraped up with a simple configuration in which a convex portion or a concave portion is provided on the outer peripheral surface thereof. Therefore, it is not necessary to add new parts, and the advantages of downsizing and weight reduction of the apparatus by employing oil bath lubrication are not impaired.

  In addition, by adopting a configuration in which each carrier is provided with a lubrication hole penetrating in the axial direction, the lubricating oil can be easily moved in the axial direction, and a necessary portion, particularly a pinion shaft portion supported by each carrier. It becomes easy to guide the lubricant. In the differential side carrier, the lubricating oil can be easily guided to the second output shaft disposed in the vicinity thereof.

  The supply of lubricating oil to the input shaft support bearing arranged at the end of the reduction gear side of the device tends to be insufficient, but the inner diameter of the speed reduction carrier is set larger than the inner ring outer diameter of the input shaft support bearing Thus, an oil supply gap is formed between the reduction gear input shaft and the inner diameter of the carrier. Thereby, the supply path of the lubricating oil from the inside of the reduction gear to the input shaft support bearing is secured.

  As described above, according to the present invention, by adopting oil bath lubrication, it is possible to maintain good lubrication of each member without using a hydraulic pump. Can be significantly reduced, and the travel distance per charge can be extended.

  Further, as the scraping means for oil bath lubrication, to adopt a configuration in which a concave portion or a convex portion as the scraping means is provided on the speed reduction side and the differential side carrier which are essential members for the speed reducer and the differential device. In addition, there is no increase in the number of parts and the above-mentioned merit due to the adoption of oil bath lubrication is not impaired.

  Further, by providing a lubrication hole in each of the carriers, it is possible to move the lubricating oil in the axial direction, and it is possible to keep the lubrication of each member well.

FIG. 1 is a cross-sectional view of the first embodiment. FIG. 2 is a partially enlarged sectional view of the above. 3 is a cross-sectional view taken along line X1-X1 of FIG. 4A is a front view of the reduction-side sun gear, and FIG. 4B is a cross-sectional view taken along line X2-X2 of FIG. 4A. FIG. 5A is a front view of the deceleration side carrier, and FIG. 5B is a cross-sectional view taken along line X3-X3 in FIG. 6 is a cross-sectional view taken along line X4-X4 of FIG. Fig.7 (a) is a front view of a differential side sun gear, FIG.7 (b) is sectional drawing of the X5-X5 line | wire of Fig.7 (a). 8A is a front view of the differential carrier, and FIG. 8B is a cross-sectional view taken along line X6-X6 in FIG. 8A. 9A is a front view of the carrier auxiliary member, and FIG. 9B is a cross-sectional view taken along line X7-X7 in FIG. 9A. FIG. 10 is an exploded cross-sectional view of a main part of the first embodiment. FIG. 11 is an enlarged perspective view illustrating a part of the gear according to the second embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[Embodiment 1]

  As shown in FIGS. 1 to 10, the electric vehicle deceleration differential apparatus according to the first embodiment includes an electric motor 11, and a planetary gear type speed reducer 12 arranged in the axial direction coaxially with the electric motor 11. The planetary gear type differential device 13 arranged in the axial direction coaxially with the speed reducer 12 and the oil bath lubrication means 14 common to the speed reducer 12 and the differential device 13.

  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. 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 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 center of 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. 3) 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. The fixed reduction side ring gear 28, the reduction side pinion gear 29 and the reduction side carrier 32 (see FIG. 1) interposed at equal intervals in three locations in the circumferential direction between the sun gear 27 and the ring gear 28.

  Deceleration side pinion gear 29 meshes with sun gear 27 and ring gear 28. The pinion gear 29 is supported by a reduction pinion shaft 31 via a needle roller bearing 33 (see FIG. 3). One end of the pinion shaft 31 is inserted into and supported by the reduction carrier 32.

  The reduction-side ring gear 28 is positioned and fixed by applying a side surface thereof to a step 34 (see FIG. 1) formed on the inner surface of the reduction differential casing 15b.

  As shown in FIGS. 3 and 4, the reduction-side pinion gear 29 is provided with a lubrication hole 38 penetrating in the axial direction at a position equally divided into three around the shaft hole 37. Each lubricating hole 38 is formed by a long hole curved in the circumferential direction. As will be described later, the lubricating hole 38 becomes a passage hole for the lubricating oil that has been scraped up and splashed off by oil bath lubrication, and has a function of reducing the weight of the pinion gear 29. The lubrication hole 38 is formed to a size that can maximize the above function within a range in which the strength of the pinion gear 29 is maintained.

  The function of the lubrication hole 38 is as follows for the lubrication holes of other members described later (the lubrication hole 45 of the speed reduction side carrier 32, the lubrication hole 56 of the differential side sun gear 51, and the lubrication hole 65 of the differential side carrier 54). Is the same.

  The speed reducing carrier 32 has a radial clearance h around the speed reducer 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. 2). As shown in FIG. 5, 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. 1) The following size is set.

  Three shaft holes 41 through which the pinion shaft 31 is inserted are provided at equal intervals on the same PCD between the center hole 39 and the outer peripheral edge of the deceleration side carrier 32. 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. 2) inserted into the screw hole 43 and a set screw 44b screwed. As a means for fixing the pinion shaft 31, there is a method in which a pin (not shown) is inserted in the pinion shaft 31 in the radial direction and the pin is fixed with a screw.

  Three lubrication holes 45 are provided on the PCD between the screw holes 43 (see FIG. 5). 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 bent from the outer peripheral edge inward 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. 2 and 5) 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 so that the pinion gear 29 can rotate smoothly.

  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.

  Therefore, in the first 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 case shown in the figure (see FIG. 2), the inner diameter of the carrier 32 and the inner diameter of the thrust bearing 47 are set equal to or larger than the inner diameter of the outer ring 23a of the bearing 23, so The clearance h is secured.

  Next, the differential device 13 will be described. The differential device 13 is provided coaxially on the opposite side of the speed reducer 12 and the electric motor 11 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.

  Note that it is conventionally known that a double pinion type is adopted in a deceleration differential device for an automobile (see Patent Document 2).

  The inner end portion of the first output shaft 35 passes through the shaft hole 55 (see FIG. 7) 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. 1) 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 includes a disc portion 49a (see FIG. 2) 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. A peripheral edge 49b is provided by bending outward (in the axial direction and in the direction in which the second output shaft 36 protrudes). 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 equal intervals in the circumferential direction (see FIG. 7). 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. 6, while meshing with each other, one pinion gear 52a has a larger PCD than the other pinion gear 52b and meshes with the ring gear 49, and the pinion gear 52b with the smaller PCD meshes with the sun gear 51.

  As shown in FIG. 8, 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. 1 and 2). 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.

  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. 8). Further, between the small diameter PCD and the center boss portion 59, lubrication holes 65 are provided at four equal intervals 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. 6). 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. 9, 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.

  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 to be integrated with the carrier auxiliary member 70.

  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 75 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 into the pinion shafts 53a and 53b in the radial direction and the pin is fixed by a screw screwed into the screw hole.

  Washers 50 for smooth rotation between the outer end surfaces of the differential-side pinion gears 52a and 52b and the differential-side carrier 54 and between the inner end surface and the differential-side carrier auxiliary member 70, respectively. Is interposed.

  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. 2). 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.

  The rotational radius of the differential carrier 54 and its auxiliary member 70 is set to be equal to or less than the oil level L of the lubricating oil stored on the inner bottom surface of the deceleration differential casing 15b. The aforementioned deceleration side carrier 32 is also set to such a size that its turning radius is less than or equal to the oil level L, but it is also possible to set the turning radius of either the differential side or the reduction side to such a size. Good.

  The electric vehicle deceleration differential apparatus of Embodiment 1 is configured as described above, and the operation thereof will be described next.

  When the electric motor 11 shown in FIG. 1 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 reduction-side sun gear integral with the reduction gear input shaft 22. 27 rotates. 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 (see paragraph 0032 of Patent Document 2).

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. 10).

  The scraped up lubricating oil is scattered inside the speed reducer 12 and applied to each component. Some of them pass axially through the lubrication hole 45 of the deceleration side carrier 32, its central hole 39, and the lubrication hole 38 of the pinion gear 29 (see the arrow in FIG. 10), or directly without passing through them. The thrust bearing 47, the input shaft support bearing 23, the needle roller 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 speed reduction pinion gear 29 having a rotation radius equal to or less than the oil level L 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. 10).

  The scraped 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. 10), or directly passes through these without supporting the second output shaft. The bearing 61, thrust bearings 76 and 77 interposed on both sides 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 equal to or less than the oil level L also contributes to the scraping action.
[Embodiment 2]

  The automobile differential gear according to the second embodiment employs the same oil bath lubrication as that of the first embodiment.

  In the case of the first embodiment, the case where oil is supplied to the bearing portion exclusively by oil bath lubrication has been described. However, since the lubricating oil is also applied to the meshing portions of the various gears, the portions are also lubricated. However, in the case of oil bath lubrication, as described above, there is a case where the lubricating oil does not reach the necessary part sufficiently. Therefore, in the second embodiment, the durability of the gear can be sufficiently exhibited even by oil bath lubrication by improving the lubricity of the gear tooth surface.

  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. 11, 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.

  Since the reduction-side pinion gear 29 and the differential-side pinion gears 52a and 52b are smaller than other gears and have a larger load torque, it is effective to apply a process for forming the indentation 83 innumerably compared to other gears. It is.

  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 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 Washer 21 Output shaft support bearing 22 Reducer input shaft DESCRIPTION OF SYMBOLS 23 Input shaft support bearing 23a Outer ring 23b Inner ring 27 Deceleration side sun gear 28 Deceleration side ring gear 29 Deceleration side pinion gear 31 Deceleration side pinion shaft 32 Deceleration side carrier 33 Needle roller bearing 34 Stepped part 35 First output shaft 36 Second output shaft 37 Shaft Hole 38 Lubrication hole 39 Center hole 40 Stepped portion 41 Shaft hole 42 Notch surface 43 Screw hole 44a Pin 44b Set screw 45 Lubrication hole 46 Convex portion 47 Thrust bearing 49 Differential side ring gear 9a disc portion 49b peripheral edge portion 50 washer 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 disc portion 59 Center boss 61 Second output shaft support bearing 62 Bearing recess 63 Inner end support bearing 64a, 64b Shaft hole 65 Lubrication hole 66 Projection 67 Fitting fixing projection 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 part 82 Tooth bottom 83 Indentation

Claims (12)

  It comprises a combination of an electric motor, a planetary gear type reduction gear, a planetary gear type differential and a lubrication means, the reduction gear comprising a reduction gear input shaft integrated with a motor output shaft of the electric motor, and the difference The moving device is provided with two output shafts that are coaxially opposed to each other as input to the deceleration output of the speed reducer, and is configured to distribute and output differential rotation to the two output shafts, and oil bath lubrication is adopted as the lubricating means. In the reduction differential for an electric vehicle, the lubricant is supplied to the movable parts of the reduction gear and the differential device by oil bath lubrication, and the reduction-side carrier that is a component of the reduction gear and the differential device And the rotation radius of at least one of the differential side carriers is formed to be smaller than the oil level of the lubricating oil accumulated at the bottom of the apparatus, and the outer peripheral surface of each carrier is formed by a convex portion or a concave portion. Reduction differential gear for an electric vehicle that has made a scooping means, characterized in that provided.   2. A reduction differential for an electric vehicle according to claim 1, wherein a lubricating hole penetrating in the axial direction is provided in each of the reduction-side carrier and the differential-side carrier, which are constituent members of the reduction gear and the differential device. apparatus.   The deceleration differential device for an electric vehicle according to claim 1 or 2, wherein the lubrication hole is formed by a long hole curved in the circumferential direction. The speed reducer includes a speed reduction sun gear integrally provided on the speed reducer input shaft, a speed reduction side ring gear fixed coaxially to a casing on the outer diameter side of the sun gear, and interposed between the sun gear and the ring gear. A reduction-side pinion gear meshed with the gear and a reduction-side carrier that supports the shaft of the pinion gear;
The differential device includes a differential side ring gear coupled to the speed reduction side carrier, a differential side sun gear provided coaxially on the inner diameter side of the ring gear, and interposed between the ring gear and the sun gear. A differential double pinion gear meshed with each other, a differential carrier that supports each shaft of the double pinion gear, and a first that is coupled to the center of the differential sun gear and penetrates the speed reducer input shaft and the motor output shaft. An output shaft and a second output shaft provided integrally with the differential carrier and disposed coaxially with the first output shaft;
The reduction gear differential for an electric vehicle according to any one of claims 1 to 4, wherein a reduction gear input shaft support bearing is provided in the reduction gear, and a second output shaft support bearing is provided in the differential gear.   The differential-side carrier has a differential-side carrier auxiliary member facing the differential-side pinion gear, with one end of the shaft of the pinion gear supported by the carrier and the other end supported by the auxiliary member. The speed-reduction differential device for electric vehicles of Claim 4 characterized by the above-mentioned.   The rotational radius of the differential side carrier auxiliary member is formed so as to be equal to or less than the oil level of the lubricating oil stored in the bottom of the apparatus, and a convex portion or a concave portion is provided on the outer peripheral surface thereof. 5. A reduction gear differential for an electric vehicle according to 5.   7. The reduction differential for an electric vehicle according to claim 4, wherein an inner diameter of the deceleration side carrier is set larger than an outer diameter of an inner ring of a support bearing of the input shaft.   5. An internal diameter of a thrust bearing in which the deceleration side carrier and the casing are interposed between surfaces facing each other in an axial direction is set larger than an outer diameter of an inner ring of the input shaft support bearing. The deceleration differential for an electric vehicle according to any one of 7.   A small number of concave depressions are randomly formed on at least the tooth surface of the reduction-side pinion gear among the gears of the reduction gear and on at least the tooth surface of the differential-side pinion gear among the gears of the differential gear. The reduction | decrease differential apparatus for electric vehicles in any one of Claim 1 to 8 characterized by the above-mentioned.   The surface roughness parameters of the tooth surface on which the infinite number of concave recesses are formed are as follows: Ryni is 2.0 to 5.5 μm, Rymax is 2.5 to 7.0 μm, and Rqni is 0.3 to 1. The reduction differential apparatus for an electric vehicle according to claim 9, wherein 1 μm and Rsk are 1.6 or less.   11. The infinite number of concave recesses formed by applying a recess forming means for causing micro hard particles to collide with a tooth surface smoothed by polishing. The reduction | decrease differential apparatus for electric vehicles of description. The electric vehicle deceleration differential apparatus according to claim 11, wherein the recess forming means is a liquid honing process.

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