JP2016070358A - Lubrication device of in-wheel motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor drive unit which can supply a lubricant to a gear of a reduction gear even in reverse traveling.SOLUTION: An in-wheel motor drive unit 21 comprises: a motor part A which generates a drive force; a reduction gear B which reduces the rotation of the motor part A, and outputs it; and a wheel hub C which transmits outputs from the reduction gear B to drive wheels. The motor part A and the reduction gear B are accommodated in a casing 22, a lubricant is sucked from a lubricant sump at a lower part of the casing 22 by the rotation of an inner rotor, and an oil pump is arranged which supplies the lubricant to the motor part A and the reduction gear B, and performs the lubrication and cooling of the motor part A and the reduction gear B. Oil grooves which suck the lubricants and supply the lubricants to gears in the reduction gear when the gears of the reduction gear rotate to a direction in which a pump drive shaft of the oil pump is inverted are formed at side faces of the gears of the reduction gear.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lubrication device for an in-wheel motor drive device.

  As shown in FIG. 11, the in-wheel motor drive device 121 includes an electric motor A that generates a driving force, a speed reducer B that decelerates and outputs the rotation of the electric motor A, and outputs from the speed reducer B to a wheel ( And a wheel hub C to be transmitted to (not shown).

  The motor part A and the speed reducer B are accommodated in the casing 122. The casing 122 includes a casing 122a on the motor part A side and a casing 122b on the reduction gear B side, and an intermediate wall 122c is provided between the casing 122a on the motor part A side and the casing 122b on the reduction gear B side. Yes.

  The motor part A uses a radial gap type of which a stator 123 is provided on the inner peripheral surface of the casing 122a and a rotor 124 is provided at an interval on the inner periphery of the stator 123.

  The rotor 124 has a motor shaft 124a in the center. The motor shaft 124a is connected to the input shaft 130 of the speed reducer A and is inserted into the casing 122b of the speed reducer B. The bearings 125a and 125b are connected to the casing 122a. And is supported rotatably. The input shaft 130 is provided with an input gear 148 in the casing 122b of the speed reducer B and transmits the rotation to the speed reduction mechanism.

  An oil reservoir 141 is provided below the reduction gear B, and the lubricating oil in the oil reservoir 141 is sucked by the oil pump 142, and the lubricating oil is supplied to the electric motor A and the reduction gear B to perform lubrication and cooling.

  The lubricating oil sucked in by the oil pump 142 is sent from the oil supply passage 143 provided in the casing 122a of the electric motor A to the internal oil passage 146 of the motor shaft 124a, and from the internal oil passage 146 by the centrifugal force and the pressure of the oil pump 142. It is supplied into the electric motor A and guided into the casing 122b of the speed reducer B by the centrifugal force and the pressure of the oil pump 142 from the internal oil passage 144 provided at the center of the input shaft 130 connected to the motor shaft 124a. It circulates to the oil sump 141 at the bottom of the B casing 122b.

  As shown in FIG. 11, the suction port 145 of the oil pump 142 is installed in the lower part of the intermediate wall 122c.

  By the way, as the oil pump 142, there is an oil pump that uses an output rotation of the electric motor A or the speed reducer B, for example, a cycloid pump (Patent Document 1). In the example of FIG. 11, the oil pump 142 is driven by the pump drive shaft 148 using the output rotation of the output gear 127 of the speed reducer B.

  When using the oil pump 142 that is driven by the internal rotational force, there is an advantage that no external driving force (power source or the like) is required.

Japanese Patent No. 4876768

  By the way, since the rotation direction of the oil pump 142 is usually determined, the pump does not function even if it rotates in the reverse direction.

  Therefore, during reverse travel, the oil pump 142 reverses, so that no lubricating oil is supplied from the oil pump 140 to the inside of the unit.

  In the casing 122b of the speed reducer B, the gears are lubricated by stirring the lubricating oil by the gears constituting the speed reducer B.

  However, when the vehicle travels in the reverse direction, such as in a garage, where the vehicle is expected to travel at a low speed, the stirring effect in the casing 122 of the speed reducer B cannot be expected. There is a risk that seizure of the constituting gear and damage of each part may occur.

  Therefore, the present invention is intended to provide an in-wheel motor drive device that can supply lubricating oil to the gears constituting the reduction gear B during back travel when the oil pump is reversely rotated.

  The present invention includes a motor unit that generates a driving force, a speed reducer that decelerates and outputs the rotation of the motor unit, and a wheel hub that transmits an output from the speed reducer to a drive wheel. The motor unit and the speed reducer An oil pump that is housed in a casing and sucks lubricating oil from a lubricating oil reservoir below the casing by rotation of the inner rotor and supplies the lubricating oil to the motor unit and the reduction gear to lubricate and cool the motor portion and the reduction gear. In the in-wheel motor drive device having the above, when the gear of the speed reducer rotates on the side surface of the gear constituting the speed reducer in the direction to reverse the pump drive shaft of the oil pump, An oil groove to be supplied to a gear in the reduction gear is formed.

  The oil groove has a spiral shape from the center of the gear toward the outer diameter side or a radial shape from the center of the gear toward the outer diameter side.

  A plate may be installed on the side surface of the gear of the speed reducer that transmits the rotational force to the pump drive shaft of the oil pump, and the oil groove may be formed between the plate and the side surface of the gear.

  The oil groove may be formed on a side surface of the side plate.

  As described above, according to the present invention, when the gear of the speed reducer that transmits the rotational force to the pump drive shaft of the oil pump reversely rotates when the vehicle is traveling backward, the center of the gear provided on the side surface of the gear is provided. Lubricating oil accumulated in the lower part of the reducer casing is sucked up by the principle of Archimedes pump by a spiral oil groove from the center of the gear toward the outer diameter side or a radial oil groove from the center of the gear toward the outer diameter side. Lubricating oil is supplied to the gears in the casing.

It is sectional drawing of the in-wheel motor drive device which concerns on this invention which shows the relationship between the input gear of the reduction gear B, a counter gear, and an output gear. It is sectional drawing of the in-wheel motor drive device which concerns on this invention which shows the relationship with the motor drive shaft which meshes | engages and drives with the output gear of the reduction gear B. It is an enlarged view of an oil pump. It is the schematic side view which looked at the gear train of the reduction gear B from the inboard side. It is a schematic side view of the gear formed with a spiral oil groove. It is a schematic side view of a gear having a radial oil groove formed therein. It is sectional drawing which shows an example of the counter gearwheel which formed the oil groove in the side surface. It is sectional drawing which shows the other example of the counter gearwheel which formed the oil groove in the side surface. It is a schematic plan view of the electric vehicle using the in-wheel motor drive device of FIG. It is the figure which looked at the electric vehicle of FIG. 9 from back. It is sectional drawing of the conventional in-wheel motor drive device.

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

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 9, an electric vehicle 11 including an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 12, front wheels 13 as steering wheels, drive wheels (rear wheels) 14, left and right And an in-wheel motor drive device 21 that transmits a drive force to each of the drive wheels 14. As shown in FIG. 10, the drive wheel 14 is accommodated in a wheel housing 12a of the chassis 12, and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12b. As a mounting form of the in-wheel motor drive device 21, any of a front wheel drive system and a four wheel drive system may be used in addition to the rear wheel drive system shown in FIGS.

  The suspension device 12b supports the driving wheel 14 by a suspension arm extending in the left-right direction, and absorbs vibrations that the driving wheel 14 (see FIGS. 9 and 10) receives from the ground by a strut including a coil spring and a shock absorber. The vibration of the chassis 12 is suppressed. Furthermore, a stabilizer that suppresses the inclination of the vehicle body when 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 driving wheels to the road surface. Is desirable.

  The electric vehicle 11 needs to be provided with a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12 by providing an in-wheel motor drive device 21 that drives the left and right drive wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a speed reducer B that decelerates and outputs the rotation of the motor unit A, and an output from the speed reducer B as driving wheels. 14 is provided in series on the same axis. The motor part A and the speed reducer B are accommodated in the casing 22 and attached to the wheel housing 12a of the electric vehicle 11 as shown in FIG.

  The motor part A and the speed reducer B are accommodated in the casing 22. The casing 22 includes a casing 22a on the motor part A side and a casing 22b on the reduction gear B side. Between the casing 22a on the motor part A side and the casing 22b on the reduction gear B side, an intermediate wall 22c that partitions the motor part A and the reduction gear B is provided.

  The motor part A uses a radial gap type in which a stator 23 is provided on the inner peripheral surface of the casing 22a, and a rotor 24 is provided at an interval on the inner periphery of the stator 23.

  The rotor 24 has a motor shaft 24a in the center, and the motor shaft 24a is connected to the input shaft 30 of the speed reducer B and is inserted into the casing 22b of the speed reducer B. The bearings 25a and 25b are connected to the casing 22a. And is supported rotatably.

  In the present invention, “outboard” means the outside of the vehicle (left side in FIG. 1), and “inboard” means the inside of the vehicle (right side in FIG. 1).

  As the motor unit A, a motor having an arbitrary configuration such as an axial gap motor can be applied in addition to the radial gap motor.

  The speed reducer B is a two-stage parallel gear speed reducer. As shown in FIG. 1, the counter gear 26 that meshes with the input gear 28 provided on the input shaft 30 connected to the motor shaft 24a of the motor unit A, An output gear 27 that meshes with the counter gear 26 is provided. An end portion on the outboard side of the input shaft 30 is supported by the output gear 27 by a bearing 31 provided in a recess formed in the center portion of the end surface on the inboard side of the output gear 27. Further, the end portion on the inboard side of the input shaft 30 is spline-fitted to the inner surface of the motor board 24 a on the outboard side, and the intermediate portion of the input shaft 30 is supported by the intermediate wall 22 c by the bearing 32.

  The counter gear 26 has a large-diameter gear 26a that meshes with an input gear 28 provided on the input shaft 30, and a small-diameter gear 26b that meshes with an output gear 27. The gear shaft 26c of the counter gear 26 is an end on the inboard side. Is supported by the intermediate wall 22c by a rolling bearing 33 provided in a recess formed on the surface of the intermediate wall 22c on the outboard side, and the end on the outboard side is the front end of the casing 22a that houses the speed reducer B. The casing 22a is supported by a rolling bearing 34 provided in a recess formed in the wall 22d.

  An output shaft 27b that is spline-fitted with the wheel hub C is provided on the outboard side of the gear shaft 27a of the output gear 27.

  As shown in FIG. 2, the lubricating oil in the lubricating oil reservoir 41 below the reducer B is sucked up at a position below the intermediate wall 22c that partitions the motor part A and the reducer B, and the lubricating oil is supplied to the motor part A. An oil pump 42 is provided that circulates inside and the speed reducer B.

  The oil supply passage 43 that supplies lubricating oil to the inside of the speed reducer B extends along the inside of the casing 22a from the discharge port of the oil pump 42 that is driven by using the output rotation of the speed reducer B that decelerates the rotation of the motor part A. And a passage extending from the rear of the casing 22a through the internal oil passage 44 of the motor shaft 24a and the internal oil passage 45 of the input shaft 30 of the speed reducer B into the casing 22b of the speed reducer B. . The lubricating oil supplied from the oil pump 42 is scattered by the centrifugal force and the pressure of the oil pump 42 from the radial supply port provided in the internal oil passage 44 of the motor shaft 24a of the motor part A, and the motor part. The inside of A is lubricated and cooled. The lubricating oil that has passed through the internal oil passage 44 of the motor shaft 24a is scattered by the centrifugal force and the pressure of the oil pump 42 from the radial supply port provided in the internal oil passage 45 of the input shaft 30 of the speed reducer B. The inside of the reduction gear B is lubricated and cooled. A so-called axial center lubrication system is adopted.

  The return passage 46 for the lubricating oil is provided at the bottom of the casing 22b of the speed reducer B. Lubricating oil scattered in the motor part A flows by gravity on the inner wall of the casing 22a of the motor part A and gathers in the lower part of the casing 22a, and gathers in the casing 22b of the speed reducer B by a through hole (not shown) provided below the intermediate wall 22c. Return to the lubricating oil reservoir 41 inside. On the other hand, the lubricating oil scattered in the speed reducer B flows through the inner wall of the casing 22b of the speed reducer B by gravity and returns to the lubricating oil reservoir 41 below the casing 22b.

  As shown in FIG. 3, the oil pump 42 includes an inner rotor 72 that rotates using the rotation of the speed reducer B, an outer rotor 73 that rotates following the rotation of the inner rotor 72, a pump chamber 74, and a feedback The cycloid pump includes a suction port 75 communicating with the passage 46 and a discharge port 76 communicating with the oil supply passage 43.

  Inner rotor 72 has a tooth profile formed of a cycloid curve on the outer diameter surface. Specifically, the shape of the tooth tip portion 72a is an epicycloid curve, and the shape of the tooth gap portion 72b is a hypocycloid curve. As shown in FIG. 2, the inner rotor 72 is rotated by a pump drive shaft 51 that is engaged with and driven by the output gear 27 of the speed reducer B.

  The outer rotor 73 has a tooth profile formed of a cycloid curve on the inner diameter surface. Specifically, the shape of the tooth tip portion 73a is a hypocycloid curve, and the shape of the tooth gap portion 73b is an epicycloid curve. The outer rotor 73 is rotatably supported by the pump case 77.

  The inner rotor 72 rotates around the rotation center c1. On the other hand, the outer rotor 73 rotates around a rotation center c2 different from the rotation center c1 of the inner rotor 72. Further, when the number of teeth of the inner rotor 72 is n, the number of teeth of the outer rotor 73 is (n + 1). In this embodiment, n = 5.

  A plurality of pump chambers 74 are provided in the space between the inner rotor 72 and the outer rotor 73. When the inner rotor 72 is rotated by the rotation of the pump drive shaft 51 that is driven by meshing with the output gear 27, the outer rotor 73 is driven to rotate. At this time, since the inner rotor 72 and the outer rotor 73 rotate around different rotation centers c1 and c2, the volume of the pump chamber 74 continuously changes. As a result, the lubricating oil flowing in from the suction port 75 is pumped from the discharge port 76 to the oil supply passage 43. In addition to the cycloid pump, a trochoid pump may be applied as an oil pump type.

  As shown in FIG. 1, the casing 22 b of the reduction gear B is provided with a lubricating oil reservoir 41 at the lower portion. The lubricating oil in the lubricating oil reservoir 41 is sucked by the oil pump 42 through the return passage 46, and the motor unit A Lubricating oil is supplied to the reducer B, and lubrication and cooling are performed.

  The pump drive shaft 51 that is engaged with and driven by the output gear 27 of the speed reducer B is provided in parallel with the axis of the output gear 27 of the speed reducer B, and the end on the outboard side is the front end of the casing 22b of the speed reducer B. It is supported by the front end wall 22d of the casing 22b by a rolling bearing 52 provided in a recess formed in the wall 22d, and the end on the inboard side is intermediate between the casing 22b of the reduction gear B and the casing 22a of the motor part A. The intermediate wall 22c is supported by a rolling bearing 53 provided in a recess formed in the wall 22c.

  A small-diameter gear 54 that meshes with the output gear 27 of the speed reducer B is provided at an intermediate portion of the pump drive shaft 51.

  The small gear 54 of the pump drive shaft 51, the output gear 27 of the speed reducer B, the input gear 28 provided on the input shaft 30, the counter gear 26 meshing with the input gear 28, and the large diameter of the counter gear 26 constituting the speed reducer B The positional relationship of the gear train such as the gear 26a and the small-diameter gear 26b of the counter gear 26 is illustrated in FIG.

  By the way, since the oil pump 42 uses a cycloid pump, when the vehicle moves forward and the pump drive shaft 51 is driven in the forward rotation direction, the lower part of the casing 22b of the speed reducer B is lubricated. Lubricating oil can be sucked from the oil sump 41 and supplied to the gear train of the speed reducer B.

  However, during reverse travel, the pump drive shaft 51 rotates in the reverse direction, so that the lubricating oil cannot be sucked from the lubricating oil reservoir 41 by the oil pump 42, so that the supply of the lubricating oil to the gear train of the reduction gear B may be delayed.

  For this reason, in the present invention, the oil groove 55 is formed on the side surface of the counter gear 26 to suck up and discharge the lubricating oil from the center of the counter gear 26 in the outer radial direction according to the principle of the Archimedes pump when the counter gear 26 rotates in the reverse direction. Forming.

  As shown in FIG. 5, the oil groove 55 is formed on the side surface of the large diameter gear 26a of the counter gear 26 in a spiral shape from the center of the gear toward the outer diameter side, or as shown in FIG. The side surface of the gear 26a has a radial shape from the center of the gear toward the outer diameter side.

  As shown in FIGS. 7 and 8, a plate 56 is installed on the side surface of the large-diameter gear 26a of the counter gear 26 so that a suction passage by the oil groove 55 is formed.

  The oil groove 55 may be provided directly on the side surface of the counter gear 26 as shown in FIG. 6, or may be provided on the inner surface of the plate 56 as shown in FIG. Moreover, the helical oil groove 55 and the radial oil groove 55 are provided on both surfaces of the large-diameter gear 26a. Plates 56 are also provided on both sides of the large-diameter gear 26a. When the spiral oil groove 55 and the radial oil groove 55 are provided on both surfaces, the lubricating oil can be sucked up effectively, but the spiral oil groove 55 and the radial oil groove 55 are large gears. Only one side of 26a may be sufficient, and plate 56 may be provided only in one side.

  When the oil groove 55 is formed on the inner surface of the plate 56, it can be processed by press processing or the like, and therefore, processing is easier than providing it on the side surface of the counter gear 26.

  In the above embodiment, an example in which the oil groove 55 is provided on the side surface of the large-diameter gear 26a of the counter gear 26 has been described. However, the oil level height h (see FIG. 4, 5, and 6), the gear provided with the oil groove 55 is not limited to the large-diameter gear 26 a of the counter gear 26 as long as the outer diameter portion of the gear is located. The small gear 26b of the counter gear 26 may be used, the small gear 54 of the pump drive shaft 51, or the output gear 27 may be used.

  As shown in FIGS. 1 and 2, the wheel hub C is spline-coupled to an output shaft 27 b formed at an end portion on the outboard side of the gear shaft 27 a of the output gear 27, and a spline portion 80 a is formed on the inner diameter surface. The inner member 80 having a double row inner ring raceway in the outer diameter portion, the outer member 81 having a double row outer ring raceway in the inner diameter surface, and the inner member 80 and the outer member 81 are provided. It consists of double row rolling elements 82.

  In the wheel hub C shown in FIGS. 1 and 2, outboard inner ring raceways of the inner members 80 are formed integrally with the inner member 80 on the outboard side, and the double row outer ring raceways are formed. A so-called third-generation member formed integrally with the inner diameter surface of the outer member 81 is shown. The wheel hub C shown in FIGS. 1 and 2 is a wheel bearing device for a double row angular ball bearing, and is not limited to the third generation, but may be the first generation or the second generation.

  A wheel mounting flange 83 is formed integrally with the inner member 80, and a brake rotor 84 and a wheel (not shown) are mounted on the wheel mounting flange 83 with bolts 85.

  The outward member 81 is fixed to the front end wall 22d of the casing 22b of the speed reducer B by a bolt 86. A knuckle (not shown), which is a vehicle body attachment member, is integrally formed on the casing 22b of the speed reducer B.

  As mentioned above, although embodiment of this invention was described with reference to drawings, the electric vehicle carrying the in-wheel motor drive device 21 concerning this invention may use a rear wheel as a driving wheel, and also uses a front wheel as a driving wheel. It may be a four-wheel drive vehicle. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

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

11: Electric vehicle 12: Chassis 12a: Wheel housing 12b: Suspension device 13: Front wheel 14: Drive wheel 21: In-wheel motor drive device 22: Casing 22a: Casing 22b: Casing 22c: Intermediate wall 22d: Front end wall 23: Stator 24 : Rotor 24a: Motor shaft 25a: Bearing 25b: Bearing 26: Counter gear 26a: Large diameter gear 26b: Small diameter gear 26c: Gear shaft 27: Output gear 27a: Gear shaft 27b: Output shaft 28: Input gear 30: Input shaft 31 : Bearing 32: Bearing 33: Rolling bearing 34: Rolling bearing 41: Lubricating oil reservoir 42: Oil pump 43: Oil supply passage 44: Internal oil passage 45: Internal oil passage 46: Return passage 51: Motor drive shaft 52: Rolling bearing 53 : Rolling bearing 54: Small diameter gear 55: Oil groove 56: Plate 72 : Inner rotor 72a: Tooth tip portion 72b: Tooth groove portion 73: Outer rotor 73a: Tooth tip portion 73b: Tooth groove portion 74: Pump chamber 75: Suction port 76: Discharge port 77: Pump case 80: Inner member 80a: Spline part 81: Outer member 82: Rolling element 83: Wheel mounting flange 84: Brake rotor 85: Bolt 86: Bolt A: Motor part B: Reducer C: Wheel hub

Claims (5)

  A motor unit that generates a driving force, a speed reducer that decelerates and outputs the rotation of the motor unit, and a wheel hub that transmits the output from the speed reducer to the drive wheels, and the motor unit and the speed reducer are accommodated in a casing The oil pump is provided with an oil pump that sucks lubricating oil from the lubricating oil reservoir below the casing by rotation of the inner rotor, supplies the lubricating oil to the motor unit and the speed reducer, and lubricates and cools the motor unit and the speed reducer. In the wheel motor driving device, when the gear of the speed reducer rotates on the side surface of the gear constituting the speed reducer in the direction to reverse the pump drive shaft of the oil pump, the lubricating oil is sucked up and the lubricating oil is geared in the speed reducer. An in-wheel motor drive device characterized by forming an oil groove to be supplied to the vehicle.   The in-wheel motor drive device according to claim 1, wherein the oil groove has a spiral shape from the center of the gear toward the outer diameter side.   The in-wheel motor drive device according to claim 1, wherein the oil groove has a radial shape from the center of the gear toward the outer diameter side.   The plate is installed in the side surface of the gear of the reduction gear which transmits rotational force to the pump drive shaft of the said oil pump, The said oil groove is formed between this plate and the side surface of a gear. The in-wheel motor drive device in any one of.   The in-wheel motor drive device according to claim 4, wherein the oil groove is formed on a side surface of the plate.

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