JP2016130572A - In-wheel motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor drive unit having a structure which can easily exchange and repair a component which is fractured by excessive torque from a wheel side so that a lock of a wheel is not caused when there occurs trouble in a reduction gear and the rotation of a motor part without dismantling the reduction gear and the motor part, and in which the fractured component does not fall and is not scattered to the outside.SOLUTION: In an in-wheel motor drive unit 21 having a motor part A which generates a drive force, a reduction gear B composed of a plurality of gears which decelerate the rotation of the motor part A, and output it, and a wheel hub C for transmitting an output from the reduction gear to a drive wheel, an end face of an inner member 41 at an inboard side that is a rotating member of the wheel hub C and an end face of an output gear 27 of the reduction gear B at an outboard side are connected to each other via a torque fuse member 32 which is broken at prescribed torque or larger, and blocks torque transmission.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an in-wheel motor drive device that prevents a wheel from being locked when trouble occurs in rotation of a motor unit or a speed reducer.

  As shown in FIG. 7, the in-wheel motor drive device 121 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 outputs from the speed reducer B to the wheel ( And a wheel hub C that transmits the motor part A and the reducer B to the casing 122.

  The casing 122 includes a cylindrical casing main body 122a, a front wall 122b fixed by bolts 122c to an opening on the outboard side (outside of the vehicle) of the casing main body 122a, and an inboard side (center of the vehicle) of the casing main body 122a. Side wall) and a rear wall 122e fixed by a bolt 122d. The casing body 122a is divided into a storage chamber for the motor part A and a storage chamber for the reduction gear B by a partition wall 122f.

  The motor part A uses a radial gap type in which a stator 123 is provided on the inner peripheral surface of the casing body 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, which is an output shaft of the motor part A, in the center. The motor shaft 124a is connected to the input shaft 130 of the speed reducer B, and is rotated with respect to the casing body 122a by bearings 125a and 125b. It is supported freely.

  The reduction gear B is a parallel gear reduction gear, and as shown in FIG. 7, a counter gear 126 provided on the input shaft 130 connected to the motor shaft 124 a of the motor unit A, and an output gear meshing with the counter gear 126. 127.

  A gear shaft 126a of the counter gear 126 is supported by the casing main body 122a and the front wall 122b via rolling bearings 126b and 126c.

  Both ends of the output gear 127 are also supported by the front wall 122b of the casing 122 and the casing body 122a via rolling bearings 128a and 128b.

  A spline shaft 127 a for transmitting power to the wheel hub C is integrally provided on the end shaft on the outboard side (outside of the vehicle) on the gear shaft of the output gear 127.

  The wheel hub C has an inner member 131 having a spline portion 131a coupled to the spline shaft 127a of the output gear 127 on the inner diameter surface, a double row inner ring raceway on the outer diameter portion, and a double row outer ring raceway on the inner diameter surface. The outer member 132 has a double row rolling element 133 provided between the inner member 131 and the outer member 132.

  A wheel mounting flange 134 is formed integrally with the inner member 131, and a brake rotor and a wheel (not shown) are mounted on the wheel mounting flange 134 with bolts 135.

  The outer member 132 is fixed to the front wall 122 b of the casing 122 by bolts 136.

  By the way, when the reduction gear B or the motor part A breaks down and the rotation is disturbed, the wheels are locked and the safety is impaired.

  For this reason, conventionally, when excessive torque is input on the power transmission path of the reducer B or the motor unit A from the wheel side, the weakest part of the parts of the reducer B or the motor unit A is caused by the excessive torque. Patent Documents 1 and 2 disclose a technique for preventing wheel lock by breaking.

JP 2010-471121 A JP 2011-148470 A

  However, in the above prior art, the weakest part that breaks when an excessive torque is input from the wheel side is provided in the components of the reduction gear B and the motor part A.

  Therefore, if the weakest part is damaged, it is necessary to disassemble the reduction gear B or motor part A and take out the internal parts for repair, or to replace the entire reduction gear B or motor part A. There are problems in that it takes time and labor and repair costs are high.

  Moreover, since the reducer B and the motor part A are rotating at high speed, the parts to be broken when excessive torque is input from the wheel side may cause the ruptured parts to fall and scatter to the outside, resulting in harm to occupants and the like. It must be out of reach.

  Therefore, in the present invention, when troubles occur in the rotation of the speed reducer B or the motor unit A, the parts that are broken by excessive torque from the wheel side are used as the speed reducer B or the motor so that the wheel is not locked. It is an object of the present invention to provide an in-wheel motor drive device having a structure that can be easily replaced and repaired without disassembling the part A, and that does not cause broken parts to fall or scatter.

  In order to solve the above problems, the present invention provides a motor unit that generates a driving force, a speed reducer that includes a plurality of gears that decelerate and output the rotation of the motor unit, and outputs from the speed reducer to the drive wheels. In an in-wheel motor drive device including a wheel hub for transmitting, an inboard side end surface of an inner member, which is a rotating member of the wheel hub, and an outboard side end surface of an output gear of a speed reducer at a predetermined torque or more It is connected through a torque fuse member that breaks and interrupts torque transmission.

  The torque fuse member is formed in a disk shape, and rotates on the surface on the outboard side of the disk-shaped torque fuse member and the surface on the inboard side of the inward member which is a rotating member of the wheel hub facing the disk. Are provided with tooth surfaces that mesh with each other so that a driving force in the direction is transmitted, and provided with a breaking protrusion that breaks at a predetermined rotational torque or more on the outer peripheral surface of the torque fuse member. Can be provided on the end face on the outboard side of the output gear of the speed reducer.

  As described above, according to the present invention, when trouble occurs in the rotation of the speed reducer or the motor unit of the in-wheel motor drive device, the breakage occurs due to excessive torque from the wheel side so that the wheel is not locked. Since the torque fuse member to be provided is provided between the end face on the inboard side of the inner member that is the rotating member of the wheel hub and the end face on the outboard side of the output gear of the speed reducer, by removing the wheel hub, The torque fuse member can be replaced and repaired.

  Further, since the torque fuse member that breaks due to excessive torque from the wheel side is provided between the wheel hub and the output gear of the speed reducer, the broken parts do not fall or scatter outside, which is safe.

It is sectional drawing which shows embodiment of the in-wheel motor drive device of this invention. It is sectional drawing which shows the state which removes the wheel hub of embodiment of FIG. 1 from a casing, and replaces | exchanges a torque fuse member. FIG. 1 and FIG. 2 are perspective views as seen from a direction in which a portion enclosed by a two-dot chain line in a square is disassembled and a tooth surface of an end face on the outboard side of a torque fuse member can be seen. FIG. 1 and FIG. 2 are perspective views as seen from a direction in which a toothed surface of an inboard side end surface of an inner member of a wheel hub can be seen by disassembling a portion surrounded by a two-dot chain line in FIGS. It is a schematic plan view of the electric vehicle which uses an in-wheel motor drive device. It is the figure which looked at the electric vehicle of FIG. 5 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. 5, 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. 6, 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, in addition to the rear wheel drive system shown in FIGS. 5 and 6, either the front wheel drive system or the four wheel drive system may be used.

  The suspension device 12b supports the drive wheel 14 by a suspension arm extending in the left-right direction, and absorbs vibration received by the drive wheel 14 (see FIGS. 5 and 6) 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 are mounted in the wheel housing 12a of the electric vehicle 11 as shown in FIG.

  The casing 22 includes a cylindrical casing main body 22a, a front wall 22b fixed by bolts 22c to an opening on the outboard side (outside of the vehicle) of the casing main body 22a, and an inboard side (center of the vehicle) of the casing main body 22a. The rear wall 22e is fixed to the opening on the side) by bolts 22d. The casing body 22a is divided into a storage chamber for the motor part A and a storage chamber for the reduction gear B by a partition wall 22f.

  A drain bolt 40 of lubricating oil is installed at the bottom of the storage chamber of the reduction gear B.

  The motor part A uses a radial gap type in which a stator 23 is provided on the inner peripheral surface of the casing body 22a, and a rotor 24 is provided at an interval on the inner periphery of the stator 23. As the motor part A, a motor having an arbitrary configuration such as an axial gap type in which a stator and a rotor are arranged to face each other through a gap opened in the axial direction can be applied.

  The rotor 24 has a motor shaft 24a, which is an output shaft of the motor part A, in the center. The motor shaft 24a is connected to the input shaft 30 of the speed reducer B and is connected to the casing body 22a by rolling bearings 25a and 25b. It is supported rotatably.

    The reduction gear B is a parallel gear reduction gear, and as shown in FIG. 1, a counter gear 26 provided on an input shaft 30 connected to the motor shaft 24 a of the motor unit A, and an output gear meshing with the counter gear 26. 27.

  The gear shaft 26c of the counter gear 26 is supported by the casing main body 22a and the front wall 22b via rolling bearings 28a and 28b.

  A gear shaft 27a on the inboard side (center side of the vehicle body) of the output gear 27 is supported by the partition wall 22f of the casing body 22a via a rolling bearing 29a.

  Further, a cylindrical flange portion 27 b projects from the end face of the output gear 27 on the outboard side (outside of the vehicle body), and the outer periphery of the cylindrical flange portion 27 b rolls to the opening portion of the front wall 22 b of the casing 22. It is supported by a bearing 29b.

  A seal member 31 is provided on the outboard side of the rolling bearing 29a. The outer peripheral surface of the cylindrical flange portion 27 b of the output gear 27 and the inner peripheral surface of the opening portion of the front wall 22 b of the casing 22 are sealed by the seal member 31.

  The cylindrical flange portion 27b provided on the end face on the outboard side of the output gear 27 is formed with a fitting recess 27c into which a fracture protrusion 32a formed on the outer peripheral surface of a torque fuse member 32 described later is fitted. (FIGS. 2, 3, and 4).

  As shown in FIGS. 1 and 2, the wheel hub C includes an inner member 41 having a double row inner ring raceway on an outer diameter portion to which the driving force of the output gear 27 is transmitted via a torque fuse member 32, and an inner diameter surface. The outer member 42 has a double-row outer ring raceway, and the double-row rolling elements 43 a and 43 b provided between the inner member 41 and the outer member 42.

  In the wheel hub C, the inner ring track on the outboard side of the double row inner ring raceways of the inner member 41 is formed integrally with the inner member 41, and the double row outer ring raceway is the inner surface of the outer member 42. Is a so-called third generation unit formed integrally.

  The double row inner ring raceway of the inner member 41 and the double row outer ring raceway of the outer member 42 are different from the PCD of the rolling element 43a arranged on the inboard side than the PCD of the rolling element 43a arranged on the outboard side. Is also provided with a larger diameter. By increasing the PCD of the rolling elements 43b arranged on the inboard side, the rigidity and load capacity of the wheel bearing device can be improved.

  The wheel hub C shown in FIG. 1 is a third generation wheel bearing device, but may be a first generation or a second generation.

  A wheel mounting flange 44 is formed integrally with the inner member 41, and a brake rotor and a wheel (not shown) are mounted on the wheel mounting flange 44 with bolts 45.

  The outer member 42 is fixed to the front wall 22b of the casing 22 by a bolt 46, and the wheel hub C can be removed from the casing 22 by the bolt 46 as shown in FIG.

  Between the inner member 41 and the outer member 42, grease is filled, and seal members 47 a and 47 b are installed on both sides of the double row rolling elements 43 a and 43 b so that the grease does not leak.

  The driving force of the output gear 27 is transmitted to the inner member 41 of the wheel hub C via the torque fuse member 32.

  As shown in FIGS. 2, 3 and 4, the torque fuse member 32 is provided separately from the inner member 41 and the output gear 27.

  3 and 4 are perspective views of a portion surrounded by a two-dot chain line in FIG. 2, and a portion of the output gear 27 facing the inboard side surface of the torque fuse member 32, and the torque fuse member 32. The part on the outboard side of the inner member 41 of the wheel hub C facing the surface on the outboard side is shown.

  The torque fuse member 32 is formed in a disk shape, and the driving force in the rotational direction is transmitted to the surface on the outboard side of the torque fuse member 32 and the surface on the inboard side of the inward member 41 opposite thereto. Thus, tooth surfaces 50a and 50b that mesh with each other are provided. The driving force is transmitted by so-called face spline fitting.

  A boss portion 52 protruding toward the outboard side is provided at the center of the surface of the disc-shaped torque fuse member 32 on the outboard side, and the torque fuse member is provided on the end surface on the outboard side of the inner member 41 of the wheel hub C. A boss hole 53 into which the 32 boss portions 52 are fitted is provided.

  On the outer peripheral surface of the disk-shaped torque fuse member 32, there is provided a fracture protrusion 32a that fits into a fitting recess 27c of a cylindrical flange portion 27b provided on the end face of the output gear 27 on the outboard side. .

  The breaking protrusion 32a is formed with such a strength as to break when the reduction gear B or the motor part A fails and an excessive torque greater than or equal to a predetermined torque is input from the wheel side.

  When the breaking protrusion 32a breaks, the engagement state with the fitting recess 27c on the end face of the output gear 27 on the outboard side is released, so that the torque fuse member 32 can be rotated with respect to the output gear 27 and the wheel is rotated. It is prevented from being locked.

  As shown in FIG. 2, since the wheel hub C is detachably fixed to the front wall 22b of the casing 22 by bolts 46, when the fracture protrusion 32a of the torque fuse member 32 breaks. By removing the wheel hub C from the front wall 22b of the casing 22, the torque fuse member 32 can be easily replaced.

  When the torque fuse member 32 is replaced, the seal member 31 is provided between the outer peripheral surface of the cylindrical flange portion 27b on the outboard side of the rolling bearing 29a and the inner peripheral surface of the opening portion of the front wall 22b of the casing 22. Since it is sealed by the oil, the oil can be exchanged without flowing out during the exchange.

  Further, since the fracture fragment of the fracture protrusion 32a of the torque fuse member 32 is accommodated in the space 51 between the front wall 22b of the casing 22 and the outer member 42 of the wheel hub C, the fracture fragment is exposed to the outside. Can prevent falling and scattering.

  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. Moreover, in the in-wheel motor drive device 21 according to the present invention, an example in which a parallel gear reducer is employed has been shown, but the present invention is not limited to this, and a planetary reducer, a cycloid reducer, and other reducers can be applied. It is.

  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 body 22b: Front wall 22c, 22d: Bolt 22e: Rear wall 22f : Partition wall 23: Stator 24: Rotor 24a: Motor shafts 25a and 25b: Rolling bearing 26: Counter gear 26c: Gear shaft 27: Output gear 27a: Gear shaft 27b: Flange portion 27c: Fitting recesses 28a and 28b: Rolling bearing 29a, 29b: Rolling bearing 30: Input shaft 31: Seal member 32: Torque fuse member 32a: Breaking protrusion 40: Drain bolt 41: Inner member 42: Outer member 43a, 43b: Rolling element 44: Wheel mounting flange 45 46: Bolts 47a, 47b: Sea Members 50a, 50b: tooth surface 51: space 52: boss 53: boss hole A: Motor unit B: reducer C: wheel hub

Claims (3)

  In an in-wheel motor drive device comprising: a motor unit that generates a driving force; a speed reducer composed of a plurality of gears that decelerates and outputs rotation of the motor unit; and a wheel hub that transmits output from the speed reducer to drive wheels. The end face on the inboard side of the inner member that is the rotating member of the wheel hub and the end face on the outboard side of the output shaft of the speed reducer are broken through a torque fuse member that cuts off torque transmission by breaking at a predetermined torque or more. An in-wheel motor drive device characterized by being connected.   The torque fuse member is formed in a disk shape, and the driving force in the rotational direction is applied to the surface on the outboard side of the torque fuse member and the surface on the inboard side of the inner member that is the rotating member of the wheel hub facing the torque fuse member. Are provided on the outer peripheral surface of the torque fuse member so as to break at a predetermined rotational torque or more. The in-wheel motor drive device according to claim 1, wherein the in-wheel motor drive device is provided on an end face of the output gear on the outboard side.   3. The in-wheel motor drive according to claim 1, further comprising a space for accommodating a broken piece of the torque fuse member between an end surface on the outboard side of the wheel hub and an end surface on the outboard side of the casing that houses the speed reducer. apparatus.

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