JP2016166639A - Cycloid reduction gear and motor drive unit having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the acoustic performance, durability and power transmission efficiency of a cycloid reduction gear.SOLUTION: A cycloid reduction gear (reduction part B) comprises: an input shaft 25 having eccentric parts 25a, 25b; curved plates 26a, 26b which are held at external peripheries of the eccentric parts 25a, 25b via a rolling bearing 40; and an oil feed passage F1 which supplies a lubricant circulating in an oil passage 25c extending to an axial direction in an input shaft 25 to an internal space of the rolling bearing 40. The rolling bearing 40 comprises: a cylindrical roller 44 interposed between an inside raceway surface 42 and an outside raceway surface 43; an inner ring 41 having circular flange parts 46, 46 which are adjacently arranged outside the cylindrical roller 44 in an axial direction; and a cage 45 which is interposed between both the raceway surfaces 42, 43, and holds the cylindrical roller 44. When a radial dimension of the flange part 46 is set as H, and a diameter dimension of the cylindrical roller 44 is set as D, a ratio of D with respect to H (=H/D) is set at 0.3 or larger and 0.5 or smaller.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cycloid reducer and a motor drive device including the same, and more particularly, a cycloid reducer applied to a reduction unit for reducing the rotation of a motor mounted on a vehicle as a driving source for driving and traveling, and The present invention relates to a motor drive device provided with the same.

The motor drive device (vehicle motor drive device) described above is housed in the interior of the wheel or disposed near the wheel, so that the weight and size of the motor drive device (vehicle performance) Affects the size of the room space. For this reason, the motor drive apparatus for vehicles needs to be as light and compact as possible. On the other hand, the vehicle motor drive device requires a large torque to drive the wheels. In order to satisfy these requirements at the same time, for example, in Patent Document 1 below, a motor unit that generates a driving force employs a high-rotation type motor that can rotate at a rotational speed of, for example, about 15000 min ^−1. An in-wheel motor drive device has been proposed as a motor drive device that employs a cycloid reducer that is compact and can provide a high reduction ratio in a speed reduction portion that decelerates the rotation of the portion.

  The speed reducer to which the cycloid reducer is applied has an eccentric part, and is rotatably held on the outer periphery of the eccentric part via an input shaft connected to the rotating shaft of the motor part and a rolling bearing, and rotates the input shaft. Along with this, there is provided a curved plate that performs a revolving motion around its rotational axis, and a motion conversion mechanism that converts the rotational motion of the curved plate generated in the revolving motion into the rotational motion of the output shaft. In the speed reduction portion having such a configuration, when the motor portion is driven, the input shaft rotates, and accordingly, a rolling bearing fitted to the outer periphery of the eccentric portion (hereinafter also referred to as “eccentric bearing”) has a curved line. A large load (mainly radial load) is repeatedly applied via a plate or the like. For this reason, as an eccentric bearing, the cylindrical roller bearing which can respond to high-speed rotation and was excellent in load capacity is used suitably. In this eccentric bearing, an annular flange is usually provided at both axial ends of the inner ring, extending radially outward and disposed on the axially outer side of the cylindrical roller. Due to the presence of such a flange portion, an induced thrust load generated due to the eccentric load on the cylindrical roller is received, and the cylindrical roller is held on the rolling surface (between both raceway surfaces).

  Moreover, said cycloid reduction gear is provided with the lubrication mechanism for lubricating and cooling the inside (contact part of members). The lubrication mechanism includes an axial oil passage extending in the axial direction inside the input shaft, and an oil supply passage for supplying lubricating oil flowing through the axial oil passage to the internal space of the eccentric bearing. . The oil supply passage is, for example, a radial oil passage that opens to the inner diameter surface of the input shaft (the inner wall surface of the axial oil passage) and the outer diameter surface of the eccentric portion, or a through hole that opens to the inner and outer diameter surfaces of the inner ring of the eccentric bearing. It is comprised including. In this case, when the cycloid reducer is driven, the lubricating oil flowing through the axial oil passage is supplied to the internal space of the eccentric bearing through the oil supply passage due to the influence of the centrifugal force generated by the rotation of the input shaft. Lubricate the inside of the eccentric bearing. Lubricating oil that has lubricated the inside of the eccentric bearing flows out of the eccentric bearing through a radial clearance formed by each of the outer diameter surface and inner diameter surface of the cage, and then is affected by centrifugal force and the like. Move outward in the direction, and lubricate the contact area between the curved plate and the inner pin.

JP 2012-148725 A

  By the way, as described above, when the cycloid reduction gear is driven (when the input shaft rotates), the eccentric bearing is operated under an environment of high rotation and high load. Therefore, even if the cycloid reduction gear is provided with the above-described lubrication mechanism (oil supply path) capable of directly supplying oil to the eccentric bearing, it has desired acoustic performance (silence), durability, and power transmission efficiency. It turned out to be insufficient for realizing a cycloid reducer.

  In view of the above situation, an object of the present invention is to provide a cycloid provided with a lubrication mechanism for lubricating and cooling a rolling bearing (eccentric bearing) or the like that is fitted to an eccentric portion of an input shaft and rotatably holds a curved plate. It is to further improve the acoustic performance, durability and power transmission efficiency of the reduction gear.

  As a result of intensive studies, the present inventors have found that the radial dimension (height dimension) of the flange provided on the inner ring of the eccentric bearing, more specifically, the radial dimension H of the flange and the eccentric bearing It is found that setting the ratio (H / D) with the diameter dimension D of the rolling element (cylindrical roller) within a predetermined numerical range is effective in solving the above-mentioned problems, and the present invention is completed. It came to.

  That is, it is considered that it is preferable to make the radial dimension (the above ratio (H / D)) as large as possible considering the function of the collar. If the radial dimension of the flange is small, the contact area between the flange and the cylindrical roller will be small, and when a large induced thrust load is applied to the flange, high surface pressure will be generated at the sliding contact portion of both. This is because abnormal noise and abnormal heat generation occur, and there is a concern that the acoustic performance and durability of the cycloid reducer may be reduced. However, for the reasons described below, the radial dimension of the collar cannot be increased unnecessarily.

  First, as described above, the eccentric bearing is used in a severe environment of high rotation and high load. Therefore, as a cage that is interposed between the inner and outer rings of the eccentric bearing and holds the cylindrical rollers at predetermined intervals in the circumferential direction, it is preferable to use a self-lubricating resin cage (resin cage). It can be said. However, if the strength required for the resin cage is to be ensured, it is necessary to give the cage a thickness in the radial direction, and therefore, between the outer diameter surface of the cage and the inner diameter surface of the outer ring, and the cage The gap width of the radial gap to be provided between the inner diameter surface of the inner ring and the outer diameter surface of the inner ring (the collar portion) is inevitably reduced. As described above, when the gap width of the radial gap is reduced, the discharge performance of the lubricating oil supplied to the inner space of the eccentric bearing via the oil supply passage is lowered. When the oil drainage from the eccentric bearing is reduced, a large stirring resistance is generated during the rotation of the eccentric bearing, and as a result, the power transmission efficiency of the cycloid reducer particularly during high speed rotation is adversely affected.

  Therefore, in the present invention, an input shaft having an eccentric portion and a curve that is rotatably held on the outer periphery of the eccentric portion via a rolling bearing and performs a revolving motion around the rotational axis as the input shaft rotates. Lubricating oil that circulates in an axial oil passage extending in the axial direction inside the input shaft, and a motion conversion mechanism that converts the rotational motion of the curved plate generated on the curved plate during revolving motion into rotational motion of the output shaft An oil supply passage that supplies the inner space of the rolling bearing to the rolling bearing, and the rolling bearing includes a plurality of cylindrical rollers that are freely rollable between the inner raceway surface and the outer raceway surface, and an inner raceway surface on the outer diameter surface. Provided with an inner ring having an annular flange disposed adjacent to the outer side in the axial direction of the cylindrical roller, and a cage for holding a plurality of cylindrical rollers interposed between the inner raceway surface and the outer raceway surface, The oil supply path includes a through hole that opens to the outer and inner diameter surfaces of the inner ring. The cycloid reducer is characterized in that the ratio (H / D) of the diameter D of the cylindrical roller to the radial dimension H of the flange is set to 0.3 or more and 0.5 or less. To do. The “rolling bearing” in the present invention corresponds to the “eccentric bearing” described above.

  When the above ratio (H / D) is less than 0.3, the contact area between the cylindrical roller and the inner ring collar part becomes too small, so that a large surface is formed on the sliding contact part between the cylindrical roller and the collar part under a large induced thrust load. As pressure is generated, abnormal noise and abnormal heat generation are likely to occur. When the ratio (H / D) exceeds 0.5, problems such as abnormal heat generation are less likely to occur, but the discharge performance of the lubricating oil supplied to the internal space of the rolling bearing is reduced and rolling. Since the agitation resistance of the lubricating oil inside the bearing is increased, the torque loss particularly during high-speed rotation is increased. On the other hand, if the ratio (H / D) is set within a range of 0.3 to 0.5, the sliding contact portion between the cylindrical roller and the flange portion is placed under a high surface pressure. While preventing problems such as abnormal heat generation as much as possible, the drainage of the lubricating oil supplied to the internal space of the rolling bearing through the oil supply passage is improved, and the power transmission efficiency during high-speed rotation is deteriorated. Can be prevented. Thereby, the cycloid reduction gear excellent in acoustic performance, durability, and power transmission efficiency is realizable.

  In the case of using a resin cage, the present invention is preferably applied to a case in which a radial thickness has to be made relatively large in order to secure a desired mechanical strength. Can do. Resin cages have better wear resistance than metal cages due to the self-lubricating property of the resin, so the above rolling bearings used in harsh environments with high rotation and high loads, and thus cycloids. This is advantageous in increasing the durability of the reduction gear.

  If the outer raceway surface is formed on the inner diameter surface of the curved plate, the outer ring of the rolling bearing can be omitted, so that the cycloid reduction gear can be reduced in weight and size.

  The cycloid reduction gear according to the present invention can be preferably applied to a speed reduction portion of a motor drive device that includes a motor portion and a speed reduction portion that reduces the rotation of the motor portion. As the motor drive device, for example, a wheel bearing portion that rotatably supports the wheel is connected to an output shaft of the speed reduction portion (in-wheel motor drive device), or an output from the speed reduction portion is transmitted to the wheel. For example, a drive shaft connected to the output shaft of the speed reduction unit and the entire device mounted on the vehicle body (on-board type motor drive device) can be used.

  As described above, according to the present invention, it is possible to realize a cycloid reduction gear excellent in acoustic performance, durability, and power transmission efficiency, and a motor driving device including the same.

It is a figure which shows the whole structure of the in-wheel motor drive device which connected the wheel bearing part to the output shaft of the reduction part among the motor drive devices which applied the cycloid reduction gear which concerns on embodiment of this invention to the reduction part. (A) A figure is the elements on larger scale of the deceleration part of the in-wheel motor drive device shown in FIG. 1, (b) A figure is the elements on larger scale of (a) figure. FIG. 2 is a cross-sectional view taken along line X1-X1 in FIG. It is explanatory drawing which shows the load which acts on a curve board. It is a cross-sectional view of a rotary pump. It is a figure which shows the whole structure of the on-board type motor drive device which connected the drive shaft to the output shaft of the reduction part among the motor drive devices which applied the cycloid reduction gear which concerns on embodiment of this invention to the reduction part. It is a schematic plan view of an electric vehicle. It is the schematic sectional drawing which looked at the electric vehicle of Drawing 7 from back.

  Based on FIG. 7 and FIG. 8, the outline | summary of the electric vehicle 11 carrying the in-wheel motor drive device as a motor drive device is demonstrated. As shown in FIG. 7, the electric vehicle 11 includes an chassis that drives each of a chassis 12, a pair of front wheels 13 that function as steering wheels, a pair of rear wheels 14 that function as drive wheels, and left and right rear wheels 14. A wheel motor drive device 21. As shown in FIG. 8, the rear wheel 14 is accommodated in the wheel housing 12a of the chassis 12, and is fixed to the lower part of the chassis 12 via a suspension device (suspension) 12b. The “electric vehicle” in the present specification is a concept including all vehicles that use electric power as driving force, and includes, for example, a hybrid car.

  The suspension device 12b supports the rear wheel 14 by a suspension arm that extends to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the road surface by a strut including a coil spring and a shock absorber. Furthermore, a stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 12b is an independent suspension type in which the left and right wheels can be moved up and down independently in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the rear wheel 14 to the road surface. desirable.

  In this electric vehicle 11, an in-wheel motor drive device 21 that rotates each of the left and right rear wheels 14 is incorporated in the left and right wheel housings 12 a, so that a motor, a drive shaft, a differential gear mechanism, and the like are mounted on the chassis 12. There is no need to provide it. Therefore, the electric vehicle 11 has an advantage that a large cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight. Moreover, in order to expand the cabin space of the electric vehicle 11, it is necessary to reduce the size of the in-wheel motor drive device 21. Therefore, an in-wheel motor drive device 21 as shown in FIG. 1 is employed.

  Based on FIGS. 1-5, the in-wheel motor drive device 21 which applied the cycloid reduction gear which concerns on embodiment of this invention to the deceleration part is demonstrated. As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and outputs from the deceleration unit B to the rear wheels. 14 (see FIGS. 7 and 8), and a wheel bearing portion C that is transmitted to 14 (see FIGS. 7 and 8). The casing 22 is mounted in the wheel housing 12a (see FIG. 8) of the electric vehicle 11.

The motor part A includes a stator 23a fixed to the casing 22, a rotor 23b disposed opposite to the inside of the stator 23a via a radial gap, and a hollow rotating shaft (motor) mounted with a rotor 23b on the outer periphery. A rotary gap) 24. The motor rotation shaft 24 can rotate at a maximum rotation speed of about 15000 min ⁻¹ .

  The motor rotating shaft 24 has ends on one side in the axial direction (right side in FIG. 1, hereinafter also referred to as “inboard side”) and the other side (left side in FIG. 1 and hereinafter also referred to as “outboard side”). The bearings are rotatably supported with respect to the casing 22 by rolling bearings (in the example shown, deep groove ball bearings) 36 and 36 disposed in the respective portions.

  The wheel bearing portion C includes a hollow hub wheel 32 having a hollow structure and a wheel bearing 33 that rotatably supports the hub wheel 32 with respect to the casing 22. The hub wheel 32 integrally includes a cylindrical hollow portion 32a connected to the output shaft 28 of the speed reduction portion B and a flange portion 32b extending radially outward from the end portion on the outboard side of the hollow portion 32a. . Since the rear wheel 14 (see FIGS. 7 and 8) is connected and fixed to the flange portion 32b by the bolt 32c, the rear wheel 14 rotates integrally with the hub wheel 32 when the hub wheel 32 rotates.

  The wheel bearing 33 is fitted to an inner member having an inner raceway surface 33 f formed on the outer diameter surface of the hub wheel 32 and an inner ring 33 a fitted to a small diameter step portion of the outer diameter surface, and an inner diameter surface of the casing 22. The outer ring 33b that is fixed together, a plurality of balls 33c disposed between the inner member and the outer ring 33b, a cage 33d that holds the balls 33c in a circumferentially spaced state, and the axial direction of the wheel bearing 33 It is a double row angular contact ball bearing provided with a pair of seal members 33e, 33e for sealing both ends.

  As shown in enlarged view in FIG. 2A, the speed reduction unit B includes an input shaft 25 that is rotationally driven by the motor unit A, an output shaft 28 that is arranged coaxially with the input shaft 25, and an input shaft 25. A cycloid reduction gear provided with a speed reduction mechanism that decelerates the rotation of the motor and transmits it to the output shaft 28 is employed. The output shaft 28 transmits the rotation of the input shaft 25 decelerated by the deceleration mechanism to the wheel bearing portion C.

  The input shaft 25 fits a spline 25g (including serrations; the same applies hereinafter) formed on the outer periphery of the end portion on the inboard side to a spline formed on the inner periphery of the end portion on the outboard side of the motor rotation shaft 24. The motor rotating shaft 24 is connected so as to be able to transmit torque by so-called spline fitting.

  As shown in enlarged view in FIG. 2A, eccentric portions 25 a and 25 b in which the shaft center is eccentric with respect to the rotational shaft center of the input shaft 25 are integrally or separately provided at two positions in the axial direction of the input shaft 25. (Integrated in this embodiment). The two eccentric portions 25a and 25b are provided with a phase difference of 180 ° in order to cancel out the centrifugal force generated by the eccentric motion (eccentric rotation).

  The input shaft 25 is rotatably supported with respect to the output side of the speed reduction unit B by rolling bearings 37a and 37b that are spaced apart from each other in two axial directions. Each of the rolling bearings 37a and 37b is a ball bearing using a ball as a rolling element.

  As shown in FIG. 1, the output shaft 28 includes a shaft portion 28b and a flange portion 28a. The flange portion 28 a has a hole portion (through hole in the illustrated example) to which an end portion on the outboard side of the inner pin 31 to be described later is fixed, and the hole portion has a circumference centering on the rotation axis of the output shaft 28. A plurality are formed at equal intervals on the top. The shaft portion 28b is connected to the hub wheel 32 of the wheel bearing portion C by spline fitting so that torque can be transmitted. The output shaft 28 is rotatably supported by the outer pin housing 60 via the outboard-side rolling bearing 48 among the rolling bearings 48, 48 arranged on both axial sides of the inner pin 31.

  As shown in FIG. 2A, the speed reduction mechanism is rotatably held on the outer periphery of the eccentric portions 25a and 25b via the rolling bearings 40 and 40, and the rotation axis is rotated as the input shaft 25 rotates. The curved plates 26a and 26b that perform the revolving motion around the center and the outer pin housing 60 are held at fixed positions and engaged with the outer peripheral portions of the curved plates 26a and 26b (during the revolving motion) to form the curved plates 26a and 26b. A plurality of outer pins 27 that cause rotation motion, a motion conversion mechanism that converts the rotation motion of the curved plates 26a and 26b to the rotation motion of the output shaft 28, and a pair that are disposed adjacent to the outer sides in the axial direction of the eccentric portions 25a and 25b. Counterweights 29, 29.

  As shown in FIG. 3, the curved plate 26 a has a plurality of waveforms formed of trochoidal curves such as epitrochoid on the outer periphery thereof. The curved plate 26a has axial through-holes 30a and 30b that open at both end faces thereof. A plurality of through holes 30a are provided at equal intervals on the circumference centered on the rotation axis of the curved plate 26a, and one inner pin 31 described later is inserted into each through hole 30a. The through hole 30 b is provided at the center of the curved plate 26 a and is fitted to the outer periphery of the eccentric portion 25 a via the rolling bearing 40.

  As shown in FIGS. 2 (a) and 3, the rolling bearing 40 has an inner raceway surface 42 on the outer diameter surface, an inner ring 41 fitted to the outer diameter surface of the eccentric portion 25a, and a curved plate 26a. An outer raceway surface 43 directly formed on an inner diameter surface (an inner wall surface defining the through-hole 30b), and a plurality of cylindrical rollers 44 disposed between the inner raceway surface 42 and the outer raceway surface 43 so as to be freely rollable; This is a cylindrical roller bearing provided with a retainer 45 (not shown in FIG. 3) that holds the cylindrical rollers 44 at predetermined intervals in the circumferential direction. The inner ring 41 integrally includes annular flanges 46, 46 that extend radially outward from both axial end portions thereof and are disposed adjacent to the axially outer side of the cylindrical rollers 44. The retainer 45 is, for example, a so-called resin retainer that is injection-molded with a resin material containing polyphenylene sulfide (PPS) or polyether ether ketone (PEEK) as a main component and an appropriate filler added thereto. used.

  Although a detailed description is omitted, the curved plate 26b has a structure similar to that of the curved plate 26a, and with respect to the eccentric portion 25b via the rolling bearing 40 similar to the rolling bearing 40 that supports the curved plate 26a. It is supported rotatably.

  The counterweight 29 has a substantially fan shape and is fitted and fixed to the outer periphery of the input shaft 25. Each counterweight 29 is arranged with a 180 ° phase shift from the eccentric portion 25a (or 25b) adjacent in the axial direction in order to cancel out the unbalanced inertia couple generated by the rotation of the curved plates 26a, 26b.

  As shown in FIG. 3, a plurality of outer pins 27 are provided at equal intervals on a circumference centered on the rotation axis of the input shaft 25. When the curved plates 26a and 26b revolve with the rotation of the input shaft 25, the outer peripheral portions of the curved plates 26a and 26b and the outer pins 27 engage with each other, causing the curved plates 26a and 26b to rotate. As shown in FIG. 2, each outer pin 27 has a pair of rolling bearings (needle roller bearings) 61, 61 arranged at both ends in the axial direction and a pair of needle roller bearings 61, 61 on the inner periphery. It is rotatably supported on the casing 22 via the held outer pin housing 60. With this configuration, the contact resistance between the outer pin 27 and the curved plates 26a and 26b is reduced.

  Although not shown in detail, the outer pin housing 60 is supported in a floating state with respect to the casing 22 by a detent means having an elastic support function. This absorbs a large radial load or moment load generated by turning or sudden acceleration / deceleration of the vehicle, and damages the components of the motion conversion mechanism that converts the rotational motion of the curved plates 26a and 26b into the rotational motion of the output shaft 28. This is to prevent it.

  As shown in FIGS. 2A and 3, the motion conversion mechanism of the present embodiment includes a plurality of through holes 30a provided in the curved plates 26a and 26b, and a plurality of one inserted into each through hole 30a. It is comprised with the inner pin 31. FIG. The inner pins 31 are arranged at equal intervals on the circumference centering on the rotation axis of the output shaft 28, and the end portion on the outboard side is fixed to the hole provided in the flange portion 28 a of the output shaft 28. Has been. A needle roller bearing 31a is provided in a portion of the inner pin 31 facing the inner wall surface of the through hole 30a. The inner diameter dimension of the through hole 30a is set larger than the outer diameter dimension of the inner pin 31 (referred to as “maximum outer diameter including the needle roller bearing 31a”; the same applies hereinafter). Since the needle roller bearing 31a is provided in this manner, the frictional resistance between the inner pin 31 and the curved plates 26a and 26b is reduced, so that torque loss in the motion conversion mechanism is prevented as much as possible.

  As illustrated in FIG. 2A, the speed reduction unit B further includes a stabilizer 70. The stabilizer 70 includes a ring-shaped annular portion 70a and a cylindrical portion 70b extending from the inner diameter surface of the annular portion 70a toward the inboard side, and the end portion on the inboard side of each inner pin 31 is an annular portion. It is fixed to 70a. As a result, when the motor part A is driven (when the input shaft 25 is rotated), the load applied to some of the inner pins 31 from the curved plates 26a, 26b is all the inner pins 31 via the output shaft 28 and the stabilizer 70. Supported by.

  Here, the state of the load acting on the curved plate 26a and further on the input shaft 25 when the motor part A is driven will be described with reference to FIG. When the motor unit A is driven, a load acts on the curved plate 26b in the same manner as described below.

The axis O ₂ of the eccentric portion 25 a provided on the input shaft 25 is eccentric from the axis (rotation axis) O of the input shaft 25 by the amount of eccentricity e. A curved plate 26a is held on the outer periphery of the eccentric portion 25a via a rolling bearing 40. Since the eccentric portion 25a rotatably supports the curved plate 26a via the rolling bearing 40, the shaft center O ₂ has a curved plate 26a. It is also the axis of The outer peripheral portion of the curved plate 26a is formed by a waveform curve, and has concave portions 34 that are recessed in the radial direction at equal intervals in the circumferential direction. Around the curved plate 26 a, a plurality of outer pins 27 that engage with the recesses 34 are arranged in the circumferential direction around the axis O of the input shaft 25.

  In FIG. 4, when the input shaft 25 rotates counterclockwise on the paper surface as the motor portion A is driven, the eccentric portion 25a and the curved plate 26a held on the outer periphery thereof are centered on the shaft center O. Since the revolving motion is performed, the concave portion 34 formed on the outer peripheral portion of the curved plate 26a sequentially contacts the outer pin 27 in the circumferential direction. As a result, the curved plate 26a rotates clockwise in response to a load Fi as indicated by an arrow in the drawing from the plurality of outer pins 27.

Further, the curve plates 26a and a plurality of circumferentially disposed around the the axis O ₂ through hole 30a, the through holes 30a, fixed to the input shaft 25 coaxially disposed output shaft 28 An internally provided pin 31 is inserted. Since the inner diameter of the through hole 30a is larger than the outer diameter of the inner pin 31, the inner pin 31 does not hinder the revolving motion of the curved plate 26a, and the inner diameter of the through hole 30a of the rotating curved plate 26a is not reduced. The rotational movement of the curved plate 26a is taken out by sliding contact with the wall surface, and the output shaft 28 is rotated (converted into the rotational movement of the output shaft 28). At this time, the output shaft 28 has a higher torque and a lower rotational speed than the input shaft 25, and the curved plate 26a receives a load Fj as indicated by arrows in the figure from the plurality of inner pins 31. The resultant force Fs of these loads Fi and Fj acts on the input shaft 25 via the rolling bearing 40.

The direction of the resultant force Fs changes due to the influence of centrifugal force in addition to geometric conditions such as the shape of the outer peripheral portion of the curved plate 26a and the number of concave portions 34. Specifically, through the rotation axis O _2, and the reference line X extending in the direction of 90 ° to the straight line Y connecting the the axis O rotation axis O _2, the angle α formed by the force Fs substantially Fluctuates between 30 ° and 60 °. The directions and magnitudes of the loads Fi and Fj change during one rotation of the input shaft 25. As a result, the resultant force Fs acting on the input shaft 25 also varies in the direction and magnitude of the load. . When the input shaft 25 rotates once, the concave portion 34 of the curved plate 26a is decelerated and rotated clockwise by one pitch, resulting in the state shown in FIG.

  The in-wheel motor drive device 21 has a lubrication mechanism that supplies lubricating oil to various portions of the motor part A and the speed reduction part B mainly in a flow as shown by white arrows in FIGS. This lubrication mechanism is provided in the oil passage 22 a provided in the wall portion of the casing 22, oil passages 24 a and 24 b provided in the motor rotation shaft 24, oil passages 25 c and 25 d 1 to 25 d 3 and 25 e provided in the input shaft 25, and the stabilizer 70. An oil passage 70c, an internal oil passage 31b provided in the inner pin 31, a drain port 22b provided in the casing 22, a lubricating oil storage portion 22d provided below the casing 22 and storing (temporarily) lubricating oil, The rotary pump 51 is configured to include an oil passage 22e provided between the lubricating oil reservoir 22d and the rotary pump 51.

  The oil passages 24a and 24b provided in the motor rotating shaft 24 extend in the axial direction and the radial direction inside the motor rotating shaft 24, respectively, and the oil passage 24a extends in the axial direction inside the input shaft 25. An oil passage 25c as an axial oil passage is connected. The oil passages 25d1 to 25d3 extend in the radial direction from the oil passage 25c toward the outer diameter surface of the input shaft 25, and the outer diameter end portions of the oil passages 25d1 to 25d3 of the present embodiment are respectively connected to the input shaft 25. Out of the outer diameter surfaces, openings are opened in substantially the same axial position as the inner diameter side opening of the oil passage 70c provided in the stabilizer 70, the outer diameter surface of the eccentric portion 25a, and the outer diameter surface of the eccentric portion 25b. The oil passage 25e extends in the axial direction from the end portion on the outboard side of the oil passage 25c, and opens to the outer end surface of the input shaft 25 on the outboard side.

  As shown in FIG. 2 (a), the inner ring 41 of the rolling bearing 40 fitted to the inboard side eccentric portion 25a has a through hole 41a opened in its inner diameter surface and outer diameter surface (inner raceway surface 42). The inner ring 41 is fitted on the outer periphery of the eccentric portion 25a so as to match the phase of the through hole 41a and the oil passage 25d2 of the input shaft 25. With this configuration, the oil passage 25c of the input shaft 25 and the internal space of the rolling bearing 40 fitted to the eccentric portion 25a communicate with each other via the oil passage 25d2 of the input shaft 25 and the through hole 41a of the rolling bearing 40. As a result, an oil supply passage F1 is formed that can supply the lubricating oil flowing through the oil passage 25c of the input shaft 25 to the rolling bearing 40 fitted to the eccentric portion 25a.

  The inner ring 41 of the rolling bearing 40 fitted to the eccentric part 25b on the outboard side also has a through hole 41a that opens to the inner diameter surface and the outer diameter surface. The inner ring 41 is connected to the through hole 41a. The input shaft 25 is fitted to the outer periphery of the eccentric portion 25b so as to be in phase with the oil passage 25d3. With this configuration, the oil passage 25c of the input shaft 25 and the internal space of the rolling bearing 40 fitted to the eccentric portion 25b communicate with each other via the oil passage 25d3 of the input shaft 25 and the through hole 41a of the rolling bearing 40. Thereby, the oil supply path F1 is formed that can supply the lubricating oil flowing through the oil path 25c of the input shaft 25 to the internal space of the rolling bearing 40 fitted to the eccentric portion 25b.

  In addition, although illustration is abbreviate | omitted, you may provide an annular groove in the axial direction position in which the oil path 25d2 is provided among the outer diameter surfaces of the eccentric part 25a, for example. In this case, since the oil passage 25d2 and the through hole 41a of the inner ring 41 can be communicated with each other via the annular groove, when the inner ring 41 is fitted to the outer periphery of the eccentric portion 25a, the oil passage 25d2 and the through hole 41a Phase alignment is not necessary. The same applies to the eccentric portion 25b.

  As shown in FIG. 1, the oil discharge port 22 b provided in the casing 22 is for discharging the lubricating oil inside the speed reduction part B to the lubricating oil storage part 22 d, and is a part in which the speed reduction part B is accommodated in the casing 22. Are provided at least at one location. The oil discharge port 22b and the oil passage 24a of the motor rotating shaft 24 are connected via a lubricating oil reservoir 22d, an oil passage 22e, and an oil passage 22a. Therefore, the lubricating oil discharged from the oil discharge port 22b to the lubricating oil reservoir 22d and stored in the lubricating oil reservoir 22d passes through the oil passage 22e and the oil passage 22a to the oil passage 24a of the motor rotating shaft 24. It flows in again.

The rotary pump 51 is provided between the oil passage 22e and the oil passage 22a connected to the lubricating oil reservoir 22d. By disposing the rotary pump 51 in the casing 22, it is possible to prevent the in-wheel motor drive device 21 from being enlarged as a whole. As shown in FIG. 5, the rotary pump 51 of the present embodiment includes an inner rotor 52 that rotates using the rotation of the output shaft 28, an outer rotor 53 that rotates following the rotation of the inner rotor 52, and both rotors The cycloid pump includes a plurality of pump chambers 54 provided in a space between 52 and 53, a suction port 55 communicating with the oil passage 22e, and a discharge port 56 communicating with the oil passage 22a. The inner rotor 52 rotates about the rotation center c ₁ , and the outer rotor 53 rotates about a rotation center c ₂ different from the rotation center c ₁ of the inner rotor 52. Further, when the number of teeth of the inner rotor 52 is n, the number of teeth of the outer rotor 53 is (n + 1), and in this embodiment, n = 5. Therefore, when the inner rotor 52 rotates as the output shaft 28 rotates, the volume of the pump chamber 54 changes continuously. As a result, the lubricating oil flowing into the pump chamber 54 from the suction port 55 is pumped from the discharge port 56 to the oil passage 22a.

  The lubrication mechanism mainly has the above configuration, and lubricates and cools each part of the motor part A and the speed reduction part B as follows.

  First, as shown in FIG. 1, in the motor portion A, the rotor 23 b and the stator 23 a are mainly lubricant oil supplied to the oil passage 24 a of the motor rotating shaft 24 via the oil passage 22 a of the casing 22. The portion is lubricated by being discharged from the opening on the outer diameter side of the oil passage 24 b under the influence of the centrifugal force generated with the rotation of the motor rotating shaft 24 and the pressure of the rotary pump 51. That is, the lubricating oil discharged from the outer diameter side opening of the oil passage 24b is supplied to the rotor 23b and then supplied to the stator 23a. Further, the rolling bearing 36 that supports the inboard side end of the motor rotating shaft 24 mainly oozes out part of the lubricating oil flowing through the oil passage 22 a from the gap between the casing 22 and the motor rotating shaft 24. To be lubricated. Furthermore, the rolling bearing 36 that supports the end portion on the outboard side of the motor rotating shaft 24 is mainly discharged from the oil passage 24b, and the inner wall surface on the outboard side of the portion of the casing 22 that houses the motor portion A. It is lubricated by the lubricating oil that has passed through.

  Next, the lubricating oil that has flowed into the oil passage 25c of the input shaft 25 via the oil passage 24a of the motor rotation shaft 24, as shown in FIG. By being affected by the pressure, the oil is supplied into the reduction portion B through the oil passages 25d1 to 25d3 and 25e.

  Specifically, first, the lubricating oil discharged from the outer diameter end portions of the oil passages 25d2 and 25d3 is supplied to the internal space of the rolling bearing 40 through the through holes 41a provided in the inner ring 41 of each rolling bearing 40. Then, the raceway surfaces 42 and 43 and the cylindrical roller 44 are lubricated. The lubricating oil that has lubricated the raceway surfaces 42, 43, etc. is between the outer raceway surface 43 and the outer diameter surface of the cage 45, and the outer diameter surface of the flange 46 provided on the inner ring 41 and the inner diameter surface of the cage 45. Are discharged to the outside of the rolling bearing 40 through radial gaps (detailed illustration is omitted) respectively formed between them, and thereafter, the curved plates 26a and 26b and the inner pins 31 (needle rollers 31) by the action of centrifugal force. It moves radially outward while lubricating the contact portion with the bearing 31a), the contact portion between the curved plates 26a, 26b and the outer pin 27, and the like. The lubricating oil discharged to the outside of the input shaft 25 through the oil passage 25e lubricates the rolling bearing 37b that supports the end of the input shaft 25 on the outboard side by the action of centrifugal force, and then the rolling bearing. 40 (especially the rolling bearing 40 fitted to the eccentric portion 25b), the contact portions between the curved plates 26a and 26b and the inner pin 31, and the like are moved radially outward while being lubricated.

  On the other hand, the lubricating oil discharged from the outer diameter end of the oil passage 25d1 is supplied to the needle roller bearing 31a via the oil passage 70c of the stabilizer 70 and the internal oil passage 31b of the inner pin 31, and the needle roller bearing. Lubricate the raceway surface and needle rollers of 31a. The lubricating oil that has lubricated the inside of the needle roller bearing 31a in this manner lubricates the contact portions between the curved plates 26a, 26b and the inner pins 31, the contact portions between the curved plates 26a, 26b and the outer pins 27, and the like. While moving radially outward. The lubricating oil discharged from the outer diameter end of the oil passage 25d1 also lubricates the inside of the rolling bearing 37a that supports the substantially central portion of the input shaft 25 in the axial direction. Further, in the present embodiment, the lubricating oil discharged from the outer diameter side opening of the oil passage 70 c is supplied to the inner oil path 31 b of the inner pin 31 on the radially outer side of the outer diameter side opening of the oil passage 70 c of the stabilizer 70. Since the guiding member 71 for guiding is provided, the lubricating oil can be efficiently supplied to the needle roller bearing 31a and the like.

  Then, the lubricating oil that has moved to the outside in the radial direction under the influence of centrifugal force and finally reached the inner wall surface of the casing 22 gathers in the lower part of the casing 22 due to gravity, and is discharged from the oil discharge port 22b. It is stored in the storage unit 22d. Thus, since the lubricating oil reservoir 22d is provided between the oil discharge port 22b and the oil passage 22e connected to the rotary pump 51, lubrication that cannot be completely discharged by the rotary pump 51 especially during high-speed rotation or the like. Even if oil is temporarily generated, the lubricating oil can be stored in the lubricating oil storage portion 22d. As a result, it is possible to prevent an increase in heat generation and torque loss at various portions of the deceleration portion B. On the other hand, especially during low-speed rotation, the amount of lubricating oil reaching the oil discharge port 22b is reduced. Even in such a case, the lubricating oil stored in the lubricating oil storage portion 22d is removed from the casing 22. Since the oil can be returned to the oil passage 24a of the motor rotating shaft 24 and further to the oil passage 25c of the input shaft 25 through the oil passage 22a and the like, the lubricating oil can be stably supplied to the motor portion A and the speed reduction portion B. Can do.

  In addition, the lubricating oil inside the deceleration part B moves radially outward also by gravity in addition to centrifugal force. Therefore, it is desirable that the in-wheel motor drive device 21 is attached to the electric vehicle 11 so that the lubricating oil reservoir 22d is positioned below the in-wheel motor drive device 21.

  The overall structure of the in-wheel motor drive device 21 is as described above, and the in-wheel motor drive device 21 of the present embodiment is a cycloid reducer in order to increase its acoustic performance (silence), durability, and power transmission efficiency. In the speed reduction part B adopting the above, a characteristic configuration as shown below is adopted.

  First, in the rolling bearing (cylindrical roller bearing) 40 that holds the curved plates 26a and 26b rotatably, as shown in FIG. 2B, the radial dimension (inner raceway surface 42) of the flange 46 provided on the inner ring 41 is obtained. And the outer diameter surface of the flange portion 46) (H), and the diameter of the cylindrical roller 44 is D, the ratio of D to H (= H / D) is 0.3 or more and 0.5. Hereinafter, it is more preferably set to 0.35 or more and 0.45 or less. This is because, as a result of intensive studies by the inventors, the radial dimension of the flange 46 provided on the inner ring 41 of the rolling bearing 40, more specifically, the radial dimension H of the flange 46 and the cylindrical roller Setting the ratio (H / D) to the diameter dimension D of 46 within a predetermined numerical range is effective in improving the acoustic performance of the cycloid reduction gear (deceleration unit B) and, consequently, the in-wheel motor drive device 21. It comes from the fact that it was found. In short, when the present inventors investigated the above ratio (= H / D), the results shown in Table 1 below were obtained. In Table 1, “◯” means that there is no problem in practical use, “Δ” means that there is a slight possibility that a problem may occur depending on use conditions, and “×” indicates that This means that there is a high possibility of problems in practical use.

  As shown in FIG. 2B and the like, since the R portion is usually provided at the outer peripheral edge portions of the both ends of the cylindrical roller 44, the ratio (H / D) is 0. When the ratio is less than 3, the contact area between the cylindrical roller 44 and the flange portion 46 of the inner ring 41 cannot be secured sufficiently. In particular, as shown in FIG. 2B, in order to finish each part of the inner ring 41 with a predetermined shape and accuracy, the cylindrical part of the inner ring 41 (the part where the inner raceway surface 42 is provided on the outer diameter surface) and the flange part 46 When the Nusumi part is provided in the vicinity of the boundary, the contact area between the cylindrical roller 44 and the flange part 46 is significantly reduced. As described above, when the contact area between the cylindrical roller 44 and the flange portion 46 is reduced, a high surface pressure is generated at the sliding contact portion between the cylindrical roller 44 and the flange portion 46 under a large induced thrust load. Even if a sufficient amount of lubricating oil is supplied to the internal space of the rolling bearing 40 via the path F1, abnormal noise and heat generation that are regarded as problems in practice are likely to occur.

  On the other hand, when the ratio (H / D) exceeds 0.5, problems such as abnormal heat generation due to the small contact area between the cylindrical roller 44 and the flange 46 are less likely to occur. Since the gap width of the radial gap provided between the radial surface and the outer raceway surface 43 and between the inner diameter surface of the retainer 45 and the outer diameter surface of the flange portion 46 is reduced, the oil supply passage F1 is used. Since the discharge performance of the lubricating oil supplied to the internal space of the rolling bearing 40 is lowered, the agitation resistance generated when the cylindrical roller 44 rolls particularly when the rolling bearing 40 rotates at a high speed is very high. growing. In particular, when the resin retainer 45 is used to provide the retainer 45 with self-lubricating properties as in the present embodiment, the retainer 45 is required to secure the strength required for the retainer 45. Since it is necessary to have a thickness in the radial direction, the tendency of the lubricating oil to be discharged becomes remarkable.

  On the other hand, as apparent from Table 1, if the ratio (H / D) is set within a range of 0.3 to 0.5 (preferably 0.35 to 0.45), Lubricating oil supplied to the internal space of the rolling bearing 40 via the oil supply passage F1 while preventing problems such as abnormal heat generation due to the contact area between the cylindrical roller 44 and the flange portion 46 being reduced as much as possible. Therefore, it is possible to suppress the stirring resistance when the rolling bearing 40 rotates at a high speed. Thereby, the cycloid reduction gear (deceleration part B) excellent in acoustic performance, durability, and power transmission efficiency, and by extension, the in-wheel motor drive device 21 can be realized.

  Further, in the rolling bearing 40, the surface roughness of at least one of the end surface of the cylindrical roller 44 and the end surface of the flange portion 46 facing each other in the axial direction is set to Ra 0.25 μm or less, more preferably Ra 0.13 μm or less. preferable. The surface roughness of at least one of the two opposing surfaces can be set to Ra 0.25 μm or less by sufficiently turning under specific processing conditions.

  Thus, if the surface roughness of the two opposing surfaces is set to Ra 0.25 μm or less, the rolling element of the rolling bearing 40 is used in view of the fact that the rolling bearing 40 is used in a severe environment of high rotation and high load. Even when it is necessary to use a relatively large diameter cylindrical roller 44, it is possible to prevent as much as possible the generation of abnormal noise and vibration associated with the sliding contact between the cylindrical roller 44 and the flange 46. Thereby, the acoustic performance and durability of the reduction part B (cycloid reduction gear) and by extension, the in-wheel motor drive device 21 can be improved further.

  The cylindrical roller 44 is preferably made of bearing steel, subjected to carbonitriding, and the amount of retained austenite in the surface layer portion is preferably 20 to 35%. Further, the inner ring 41 is preferably made of bearing steel, subjected to carbonitriding treatment, the amount of retained austenite in the surface layer is 25 to 50%, and the amount of retained austenite in the core is preferably 15 to 20%. In this way, the rolling fatigue life can be improved and the generation and development of cracks can be suppressed. Therefore, the durability of the rolling bearing 40 and thus the in-wheel motor drive device 21 can be improved (long life). ). Further, in order to ensure the same life, it is possible to reduce the thickness of the raceway compared to the case where raceways (inner and outer races) that do not have the above configuration are employed. Therefore, the in-wheel motor drive device 21 can be reduced in size and weight through, for example, downsizing the rolling bearing 40 in the radial direction.

  Although not shown in detail, the curved plates 26a and 26b are formed of case-hardened steel such as SCM415, SCM420, and SCr420, and are surface hardened by subjecting them to carburizing and tempering as heat treatment. It is preferable to have a layer.

  In this way, even in the present embodiment in which the outer raceway surface 43 of the rolling bearing 40 is directly formed on the inner diameter surface of the curved plate 26a, wear and damage due to transfer of the cylindrical roller 44 on the outer raceway surface 43 is possible. It can be prevented as much as possible. Moreover, if the hardened layer accompanying carburizing quenching and tempering is formed on the surface layer portion of the curved plates 26a and 26b, the outer peripheral portion of the curved plates 26a and 26b may be deformed by the load applied from the outer pin 27, or The inner surface of the through hole 30a provided in the curved plates 26a and 26b is deformed by a load applied from the inner pin 31, or the inner pin is worn with sliding with the pin 27. It is possible to effectively prevent wear due to sliding with 31 (needle roller bearing 31a). Therefore, the durability of the curved plates 26a and 26b and the speed reduction part B can be increased.

  On the other hand, if the above-mentioned thing is employ | adopted as curved board 26a, 26b, the hardened layer will not be formed in the core part of curved board 26a, 26b, In this case, curved board 26a, 26b has toughness. . Thereby, for example, even when an instantaneous impact load is input to the deceleration portion B via the wheel bearing portion C during driving of the vehicle, the curved plates 26a and 26b may be deformed or damaged by the impact load. Can be effectively reduced. In addition, the case-hardened steel is relatively soft and rich in workability before the heat treatment (carburizing quenching and tempering), so that the curved plates 26a and 26b having complicated shapes can be produced efficiently. Moreover, since the carburizing and quenching tempering selected as the heat treatment method has flexibility in changing the shape, the cost required for newly producing and changing the design of the curved plates 26a and 26b can be reduced.

  The overall operation principle of the in-wheel motor drive device 21 having the above configuration will be described with reference to FIGS. 1 and 4.

  In the motor part A, for example, the rotor 23b made of a permanent magnet or a magnetic material rotates by receiving an electromagnetic force generated by supplying an alternating current to the coil of the stator 23a. Accordingly, when the input shaft 25 connected to the motor rotation shaft 24 rotates, the curved plates 26 a and 26 b revolve around the rotation axis of the input shaft 25. At this time, the outer pin 27 engages with the curved waveform provided on the outer periphery of the curved plates 26a and 26b in the circumferential direction, and the curved plates 26a and 26b rotate in the direction opposite to the rotation direction of the input shaft 25. Rotate.

  The inner pin 31 inserted through the through hole 30a comes into contact with the inner wall surface of the through hole 30a as the curved plates 26a and 26b rotate. Thereby, the revolution movement of the curved plates 26 a and 26 b is not transmitted to the inner pin 31, but only the rotational motion of the curved plates 26 a and 26 b is transmitted to the wheel bearing portion C via the output shaft 28. At this time, the rotation of the input shaft 25 is transmitted to the output shaft 28 after being decelerated by the decelerating unit B. Therefore, even when the low-torque, high-rotation type motor unit A is employed, the drive wheels (rear wheels) 14 It is possible to transmit the torque required for.

The speed reduction ratio of the speed reducing portion B having the above-described configuration is expressed as (Z _A −Z _B ) where Z _{A is} the number of outer pins 27 and Z _B is the number of waveforms (recesses 34) provided on the outer peripheral portions of the curved plates 26a and 26b. ) / is calculated by Z _B. In the embodiment shown in FIG. 3, since Z _A = 12 and Z _B = 11, a very large reduction ratio of 1/11 can be obtained.

  In this way, by adopting the speed reduction unit B that can obtain a large speed reduction ratio without using a multi-stage configuration, the in-wheel motor drive device 21 having a compact and high speed reduction ratio can be obtained. Further, by providing rolling bearings (needle roller bearings) 61 and 31a that rotatably support the outer pin 27 and the inner pin 31, friction between the curved plates 26a and 26b and the outer pin 27 and the inner pin 31 is achieved. Since the resistance is reduced, the power transmission efficiency in the speed reduction portion B is also improved from this point.

  As described above, the in-wheel motor drive device 21 of this embodiment is light and compact as a whole device. Therefore, if the in-wheel motor drive device 21 is mounted on the electric vehicle 11, the unsprung weight can be suppressed, so that the electric vehicle 11 excellent in running stability and NVH characteristics can be realized.

  As mentioned above, although the motor drive device (in-wheel motor drive device 21) which applied the cycloid reducer which concerns on embodiment of this invention to the deceleration part B was demonstrated, the summary of this invention is included in the in-wheel motor drive device 21. FIG. Various changes can be made without departing from the scope of the invention.

  For example, in the above description, the cycloid pump is adopted as the rotary pump 51 constituting the lubrication mechanism. However, the present invention is not limited to this, and any rotary pump driven by using the rotation of the output shaft 28 can be adopted. Furthermore, the rotary pump 51 may be omitted, and the lubricating oil may be circulated only by centrifugal force.

  In the above description, the eccentric portions 25a and 25b are provided at two positions in the axial direction of the input shaft 25. However, the number of the eccentric portions can be set arbitrarily. For example, the eccentric portions can be provided at three positions in the axial direction of the input shaft 25. In this case, the eccentric portions change the phase by 120 ° so as to cancel the centrifugal force generated by the rotation of the input shaft 25. It is preferable to provide it.

  In the above description, the motion conversion mechanism is mainly configured by the through holes 30a provided in the curved plates 26a and 26b and the inner pins 31 slidably fixed to the output shaft 28 with the inner wall surface of the through holes 30a. However, the motion conversion mechanism is not limited to this, and may have any configuration that can transmit the rotational motion of the curved plates 26a and 26b to the hub wheel 32 of the wheel bearing portion C.

  The description of the operation in the present embodiment has been made by paying attention to the rotation of each member, but in reality, power including torque is transmitted from the motor part A to the rear wheel 14. Therefore, the power decelerated as described above is converted into high torque.

  Moreover, although the case where the electric power is supplied to the motor unit A to drive the motor unit A and the power from the motor unit A is transmitted to the rear wheel 14 is shown, the vehicle decelerates or slopes are reversed. When it falls, the power from the rear wheel 14 side can be converted into high-rotation and low-torque rotation by the speed reduction part B and transmitted to the motor part A, and the motor part A can generate power. . Furthermore, the electric power generated here can be stored in a battery and used as electric power for driving the motor unit A and electric power for operating other electric devices provided in the vehicle.

  Further, in the embodiment described above, a radial gap motor is adopted as the motor part A, but the present invention adopts an axial gap motor that makes the motor part A face the stator and the rotor through an axial gap. In this case, it can be preferably applied.

  Further, the in-wheel motor drive device 21 according to the present invention is not limited to the rear wheel drive type electric vehicle 11 having the rear wheel 14 as the drive wheel, but also the front wheel drive type electric vehicle having the front wheel 13 as the drive wheel, The present invention can also be applied to a four-wheel drive type electric vehicle having 13 and rear wheels 14 as drive wheels.

  The cycloid reducer according to the present invention is a motor drive device for an electric vehicle other than the in-wheel motor drive device, for example, the drive shaft is connected to the output side (output shaft 28) of the reduction unit B so that torque can be transmitted, The present invention can also be preferably applied to a reduction portion of a so-called on-board type motor drive device in which the entire device is mounted on a vehicle body.

  Here, an example of the on-board type motor driving device will be described with reference to FIG. The motor drive device 81 shown in the figure includes a motor unit A ′ that generates a driving force, a deceleration unit B ′ that decelerates and outputs the rotation of the motor unit A ′, a deceleration unit B ′, and driving wheels (rear wheels). 14 and two drive shafts 100 are provided to individually rotate and drive the pair of left and right drive wheels 14. The two motor parts A 'are coaxially arranged adjacent to each other back to back, and the pair of left and right reduction parts B' and the drive shaft 100 are arranged coaxially with the motor part A '. The motor unit A ′ and the reduction unit B ′ of the motor drive device 81 have basically the same configuration as the motor unit A and the reduction unit B applied to the in-wheel motor drive unit 21 shown in FIGS. The thing is adopted. Therefore, detailed description of the structure, operation mode, and the like of the motor unit A ′ and the deceleration unit B ′ will be omitted.

  The drive shaft 100 includes a fixed type constant velocity universal joint 101 on the drive wheel 14 side, a sliding type constant velocity universal joint 102 on the speed reduction portion B ′ side, and an intermediate shaft 103 that connects the two constant velocity universal joints 101 and 102. Is the main configuration. The output shaft of the speed reduction unit B ′ is connected to the sliding type constant velocity universal joint 101 by spline fitting, and the output of the speed reduction unit B ′ is transmitted to the drive wheel 14 via the drive shaft 100.

  In the motor drive device 81 shown in FIG. 6, in order to individually drive the left and right drive wheels 14, two motor parts A ′ and two speed reduction parts B ′ are provided, and two speed reduction parts B ′ are provided. The cycloid reducer according to the present invention is applied to each, but the cycloid reducer according to the present invention is an on-board type motor drive provided with one motor part A ′ and one reducer part B ′. The present invention can also be preferably applied to the deceleration portion B ′ of the apparatus.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 11 Electric vehicle 21 In-wheel motor drive device 22 Casing 25 Input shaft 25a, 25b Eccentric part 26a, 26b Curved board 27 Outer pin 28 Output shaft 40 Rolling bearing 41 Inner ring 42 Inner raceway surface 43 Outer raceway surface 44 Cylindrical roller 46 ridge part 81 Motor drive device 100 (on-board type) Drive shaft A Motor part A ′ Motor part B Deceleration part (cycloid reduction gear)
B 'Reducer (Cycloid Reducer)
C Wheel bearing part D Diameter dimension of cylindrical roller F1 Oil supply path H Radial dimension of flange

Claims (5)

An input shaft having an eccentric portion, a curved plate that is rotatably held on the outer periphery of the eccentric portion via a rolling bearing, and that performs a revolving motion around the rotational axis as the input shaft rotates, A motion converting mechanism for converting the rotational motion of the curved plate generated in the curved plate in motion into a rotational motion of an output shaft, and lubricating oil flowing through an axial oil passage extending in the axial direction inside the input shaft. An oil supply passage for supplying the internal space of the rolling bearing,
The rolling bearing is provided with a plurality of cylindrical rollers rotatably arranged between an inner raceway surface and an outer raceway surface, and the inner raceway surface is provided on an outer diameter surface, and is disposed adjacent to the outer side in the axial direction of the cylindrical roller. An inner ring having an annular flange, and a cage that is interposed between the inner raceway surface and the outer raceway surface and holds the plurality of cylindrical rollers, and the oil supply path is disposed outside the inner ring. In a cycloid reducer configured to include a through-hole opened in a radial surface and an internal diameter surface,
The cycloid reduction gear characterized by setting ratio (H / D) of the diameter D of the said cylindrical roller with respect to the radial direction dimension H of the said collar part to 0.3-0.5.   The cycloid reducer according to claim 1, wherein the cage is made of resin.   The cycloid reducer according to claim 1 or 2, wherein the outer raceway surface is formed on an inner diameter surface of the curved plate.   A wheel that includes a motor unit and a deceleration unit that decelerates rotation of the motor unit, wherein the cycloid reducer according to any one of claims 1 to 3 is applied to the deceleration unit, and the wheel is rotatably supported. A motor drive device in which a bearing portion is connected to the output shaft.   A cycloid speed reducer according to any one of claims 1 to 3 is applied to the speed reduction part, and the output from the speed reduction part is a wheel. A motor drive device in which a drive shaft for transmission to the output shaft is coupled to the output shaft.

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