JP6548456B2 - Wheel drive braking system - Google Patents

Description

  The present invention relates to a wheel drive braking device applied to an electric vehicle equipped with an electric motor for driving.

  BACKGROUND In recent years, electric vehicles and hybrid vehicles (hereinafter, collectively referred to as “electric vehicles”) that use an electric motor as a drive source have become widespread. Among such electric vehicles, there are in-wheel motor electric vehicles in which an electric motor is disposed inside a wheel or coaxially integrated with a wheel hub.

  Many such in-wheel motor type electric vehicles are equipped with a reduction mechanism integrally with the electric motor so that the rotation of the electric motor is reduced and transmitted to the wheel. This is because the drive wheels can be driven with low rotation and high torque while using a high efficiency and high rotation electric motor.

  For example, FIG. 2 is a longitudinal sectional view showing a drive braking device for wheels of an in-wheel motor type electric vehicle disclosed in Patent Document 1. As shown in FIG. As shown in FIG. 2, a driving electric motor 102 is mounted on the wheel 111 of the wheel 101 by the in-wheel motor method, a reduction mechanism 103 interposed between the wheel 111 and the electric motor 102, and the wheel 111. Are arranged in this order from the center side of the vehicle body to the side of the vehicle body side by side in the axle shaft direction. In addition, let the thing by which the tire 112 was mounted | worn with the wheel 111 be the wheel 101. FIG.

  The hub 113 of the wheel 111 is fastened to the output shaft 131 of the speed reduction mechanism 103 by a bolt 115, and the outer periphery of the projecting portion 114 projecting to the vehicle center side of the hub 113 and the outer periphery of the projecting portion 132 projecting to the vehicle side of the output shaft 131 Is pivotally supported by the inner race (inner race) 161 of the bearing 106. An outer race (outer race) 162 of the bearing 106 is supported by a casing 104 on the vehicle body side that accommodates the electric motor 102 and the reduction mechanism 103. A braking mechanism 107 is disposed on the outer peripheral side of the bearing 106 in the casing 104.

JP-A-2-11419

However, the technique according to the conventional drive braking device for wheels as in Patent Document 1 has the following problems.
That is, in the above-described technology, the device is miniaturized in the axial direction by arranging the braking mechanism 107 including a disk, a cylinder, a piston and the like on the outer peripheral side of the bearing 106 in the casing 104. This can be done because the outer diameter of the projection 132 of the output shaft 131 and the projection 114 of the hub 113 disposed inside the bearing 106 is kept small.

  However, for example, in the case of a front-wheel drive vehicle that drives the front wheel, which is a steered wheel, the steering operation force increases, and in order to reduce this, the convex portion 114 of the wheel 111 is expanded in diameter [eg, the maximum of the wheel 111 The diameter expanded to about half of the outer diameter (rim diameter) is increasing. In the case of a wheel having a large outer diameter of such a convex portion, the bearing 106 has a large diameter, the space on the outer peripheral side of the bearing 106 in the casing 104 is reduced, and it becomes difficult to incorporate the braking mechanism 107. It will have to be made larger in the radial direction.

  The present invention is intended to solve the above-mentioned problems, and restrains the size of the device in the radial direction and the axial direction even when the outer diameter of the convex portion protruding to the vehicle body center side of the wheel hub is large. It is an object of the present invention to provide a drive braking device for a wheel that can be used.

(1) In order to achieve the above object, the drive braking system for a wheel according to the present invention comprises a drive electric motor mounted in-wheel on a wheel of a wheel mounted on an electric vehicle, the wheel, and the wheel A power transmission mechanism having an internal gear for output and interposed between an electric motor and connected to the wheel and capable of changing the rotational speed, and a bearing rotatably supporting the wheel on the vehicle body of the vehicle And a braking mechanism for applying a braking force to the wheel, wherein the electric motor, the power transmission mechanism, and the hub of the wheel are arranged along an axle direction of the wheel. The output internal gear and the hub are arranged in this order from the center of the vehicle body to the side of the vehicle, the output internal gear and the hub are adjacent along the axle direction, and the outer peripheral portion of the output internal gear and the hub are powered. Connecting part to connect There is equipped with the bearing and the brake mechanism, the outer peripheral side of the connecting member, is arranged along the axle direction, wherein the brake mechanism includes a cylinder that is provided on the outer ring side of the bearing, the said cylinder It is characterized in that it comprises: a piston whose tip is protruded according to a braking pressure which is inserted and supplied to the cylinder; and a brake disk surface formed on the vehicle body center side of the inner ring of the bearing .

  (2) It is preferable that the inner ring of the said bearing is formed in the said connection member.

  According to the present invention, since the connecting member for power connecting the internal gear for output of the power transmission mechanism and the hub of the wheel is disposed on the outer peripheral side of these, the increase of the axial dimension of the device is suppressed. Can. Further, since the bearing and the braking mechanism are provided side by side along the axle direction on the outer peripheral side of the connecting member, it is possible to suppress an increase in the radial dimension of the device. Further, since the bearing and the braking mechanism are juxtaposed in the direction of the axle, the diameter of the bearing can be increased while suppressing the radial dimension of the device. Even if the diameter is large, accommodation is possible.

It is a longitudinal cross-sectional view (only an upper half shows) of the wheel which shows the drive-braking apparatus of the wheel concerning one Embodiment of this invention, and its axle part. FIG. 1 is a longitudinal sectional view of an axle portion showing a wheel drive braking system according to the background art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the embodiments described below are merely illustrative, and there is no intention to exclude the application of various modifications and techniques that are not specified in the following embodiments. The configurations of the following embodiments can be variously modified and implemented without departing from the scope of the invention, and can be selected or combined as appropriate.

〔Constitution〕
FIG. 1 is a longitudinal sectional view showing an upper half portion of an axle center CL of a wheel and an axle portion of a wheel. The vehicle according to the present embodiment is an electric vehicle (electric vehicle or hybrid vehicle) including an electric motor as a drive source. As shown in FIG. 1, the drive electric motor 2 mounted on the vehicle is mounted on the wheel 11 of the wheel 1 by an in-wheel motor system, that is, coaxially disposed inward of the wheel 11. ing. In addition, let the thing by which the tire which is not shown in figure was mounted | worn with the wheel 11 be the wheel 1. FIG.

  Between the wheel 11 and the electric motor 2, a transmission mechanism 3 and an output internal gear 31 are provided as a power transmission mechanism 3A capable of changing the rotational speed. The transmission mechanism 3 needs to apply a small size that can be accommodated inside the casing (axle case) 4 together with the electric motor 2. For example, a multi-disk transmission mechanism is preferable. The output rotation of the transmission mechanism 3 is output from the output internal gear 31 to the wheel 11 side. In addition, the electric motor 2, the power transmission mechanism 3A, and the hub 12 of the wheel 11 are directed from the vehicle center side (inside of the vehicle) IS to the side of the vehicle (outside of the vehicle) OS along the axle direction (direction of axle center CL). They are arranged in this order.

  The multi-disk transmission mechanism is a known transmission mechanism disclosed in, for example, Japanese Patent No. 4668307, Japanese Patent No. 5683748, and the like. Although this multi-disc transmission mechanism is not shown, an input shaft coaxially connected to the output shaft 21 of the electric motor 2, an output shaft disposed parallel to the input shaft, and a disk-shaped input disk provided on the input shaft And a disc-shaped output disc provided on the output shaft and arranged to overlap with the input disc.

  Further, in the overlapping area of the input disc and the output disc, the pressing means is movable along an axial center connecting line connecting the axis of the input shaft and the axis of the output axis. The pressing means is moved to a position according to the required gear ratio, and both discs are elastically deformed and pressed so as to be in pressure contact with each other, thereby forming a torque transmission contact portion between both discs. When the pressure is released, the torque transmission is interrupted by the elastic restoring force of both disks.

  An output pinion (not shown) engaged with the output internal gear 31 is fixed to the output shaft of the multi-disc transmission mechanism. Therefore, the rotation of the electric motor 2 is shifted by the transmission mechanism 3 at a transmission gear ratio corresponding to the position of the torque transmission contact portion (the radial position of the disk), and output from the output pinion to the output internal gear 31.

  In other words, since the input and output shafts of the multi-disk transmission mechanism are arranged in parallel as described above, the output shaft is eccentrically arranged with respect to the output shaft 21 and the input shaft of the motor 2 coaxially arranged along the axle center CL. It will be done. Therefore, the multi-disk transmission mechanism is suitable as a transmission mechanism to be combined with the output internal gear 31 having a relatively large diameter.

  In the case of a belt-pulley type continuously variable transmission, it is necessary to increase the distance between the input and output shafts to avoid interference between the two pulleys, but in the case of a multi-disc transmission mechanism, the distance between the input and output shafts Since the distance between the shafts can be set to be slightly larger than the radius of the disk, the distance between the axes can be set short, which is suitable as the transmission mechanism of the in-wheel motor drive mechanism.

  The output internal gear 31 and the hub 12 of the wheel 11 are power-connected by the connecting member 5. The connecting member 5 includes an internal gear connecting portion 51 which is power-connected to the outer peripheral portion of the output internal gear 31 and a wheel hub connecting portion 52 which is power-connected to the convex portion 12 a which protrudes to the vehicle body center side IS of the hub 12. And a base portion 53 connecting the internal gear connection portion 51 and the wheel hub connection portion 52.

  The internal gear connection portion 51 is formed in a cylindrical shape having an inner periphery along the outer peripheral portion of the output internal gear 31. In the present embodiment, the wheel hub connecting portion 52 includes a disc-like portion 52 a formed in a disk shape extending from the vehicle body side OS of the internal gear connecting portion 51 toward the axle center CL, and the axle center CL. And a boss 52b formed along the same. The convex portion 12a of the hub 12 is formed in an annular shape having a hole portion 12b, and the convex portion 12a of the hub 12 is externally fitted with the hole portion 12b in the boss portion 52b, and an annular surface 12c facing the vehicle center side IS Is abutted against the disc-like portion 52a and connected by fastening of a bolt (not shown).

  Further, the base portion 53 is formed in an annular shape in which the main portion thereof protrudes toward the vehicle body side OS more than the disc-shaped wheel hub connecting portion 52. The protrusion of the main portion of the base portion 53 to the vehicle body side OS is located in the recessed space on the outer peripheral side of the convex portion 12 a of the hub 12. Further, the internal gear coupling portion 51 is formed to project from the base portion 53 toward the vehicle center side IS.

  A bearing 6 rotatably supporting the output internal gear 31 and the wheel 11 on the casing 4 is disposed on the outer peripheral side of such a connecting member 5. As the bearing 6, a ball bearing including a ball 61, an inner ring 62 and an outer ring 63 is used. In the present embodiment, the inner ring 62 is integrally formed with the base 53 on the outer peripheral side of the base 53 of the connecting member 5. The outer ring 63 is coupled and fixed to the casing 4 by a bolt 41.

  The bearing 6 is, as an axial position (a position in the direction along the center line CL of the axle), a position shifted to the vehicle side OS from the output internal gear 31, that is, a space on the outer peripheral side of the hub 12. And is disposed at a position substantially along the outer peripheral surface of the convex portion 12a. Therefore, a space is formed on the outer peripheral side of the output internal gear 31 and the internal gear connection portion 51. In the present embodiment, the bearing 6 is provided with the balls 61 in only one row in the axial direction, and the axial length of the bearing 6 is suppressed, so the space on the outer peripheral side of the internal gear coupling portion 51 is in the axial direction Are also secured large. The braking mechanism 7 is disposed in this space.

The braking mechanism 7 is fixed to the outer ring 63 of the bearing 6 by a bolt 76 and restricted in rotation, and is inserted into the cylinder 71 and an annular cylinder 71 surrounding the internal gear connecting portion 51. The tip has an axial direction (the center line of the axle according to the hydraulic pressure (braking pressure) of the hydraulic oil supplied to the oil chamber 72 of the cylinder 71, having a convex portion (not shown) fitted in the concave portion (not shown). And a brake disc surface 74 formed on the inner ring 62 of the bearing 6, and a brake pad 75 provided at the tip of the piston 73. When the oil pressure in the oil chamber 72 increases, the tip of the piston 73 strokes to the side OS of the vehicle body, and the brake pad 75 contacts the brake disc surface 74. As a result, the frictional force between the brake pad 75 and the brake disk surface 74 is transmitted to the non-rotational outer ring 63 through the piston 73 and the cylinder 71, thereby applying a braking force to the inner ring 62 side.
In this manner, the cylinder 71 is disposed on the outer peripheral side of the internal gear coupling portion 51, and the side surface of the vehicle center side IS of the inner ring 62 of the bearing 6 is utilized as the brake disc surface 74. The space on the outer peripheral side of the above can be used effectively, and the axial length of the device can be shortened.

  In the present embodiment, the cylinder 71 is mounted on the outer ring 63, but the cylinder 71 may be mounted on the outer ring 63 side (non-rotation side) of the bearing 6, for example, may be mounted on the casing 4. The brake disc surface 74 may also be formed on the inner ring 62 side of the bearing 6. Further, in the present embodiment, the cylinder 71 and the piston 73 are formed in an annular shape, but for example, a general cylindrical cylinder 71 and the piston 73 or only a cylindrical piston 73 is divided into a plurality of It may be arranged intermittently along the outside of the tooth gear connection portion 51 in a circular manner.

  If the piston 73 is divided into a plurality of parts, the oil chamber 72 is also divided similarly, but if the piston 73 is annular, the oil chamber 72 may be annular or the oil chambers 72 may be divided into a plurality. It is also possible to divide and arrange in a circle in an intermittent manner, and to project individual pistons axially moving in the respective oil chambers 72 on the back surface of the annular piston 73.

  In addition, the seal ring 77 which seals the hydraulic fluid in the oil chamber 72 is equipped on the inner periphery and the outer periphery of the piston 73, and the ball 61 of the bearing 6 is also provided on the surface on which the brake pad 75 at the tip of the piston 73 is equipped. A seal ring 78 is provided to seal the lubricating oil in the receptacle of the Furthermore, the vehicle body side OS of the bearing 6 is also equipped with a seal ring 81 for sealing the lubricating oil in the housing portion of the ball 61 through the bracket 80 coupled and fixed to the casing 4 together with the outer ring 63 by fastening the bolt 41.

[Action and effect]
The wheel drive braking device according to the embodiment of the present invention is configured as described above, and therefore, the device is also provided when the outer diameter of the convex portion 12 a protruding to the vehicle body center side of the hub 12 of the wheel 11 is large. An increase in the axial dimension of the device and an increase in the radial dimension of the device can be suppressed.

  That is, since the connecting member 5 for power-connecting the output internal teeth 31 of the power transmission mechanism 3A and the hub 12 of the wheel 11 is disposed on the outer peripheral side, suppressing an increase in the axial dimension of the device Can.

  Further, if the connecting member 5 is arranged on the outer peripheral side, the bearing 6 is arranged on the outer peripheral side of the connecting member 5, and the braking mechanism 7 is further arranged on the outer peripheral side of the bearing 6, the radial dimension of the device is increased. However, since the bearing 6 and the braking mechanism 7 are arranged side by side along the axle direction (the direction of the axial center CL) on the outer peripheral side of the connecting member 5, the diameter of the bearing 6 may be increased to some extent. An increase in radial dimension can be suppressed.

  When the diameter of the bearing 6 is expanded, the space on the inner peripheral side of the bearing 6 is expanded in diameter, so that the projection 12a having a large outer diameter can be accommodated using this space. In recent years, the diameter of the convex portion 12a of the hub 12 of the wheel 11 has been increased (for example, the diameter has been increased to about half of the maximum outer diameter (rim diameter) of the wheel 11). Even wearing it becomes possible.

  Further, if the diameter of the bearing 6 is enlarged, the load load on the individual balls 61 of the bearing 6 is reduced, so that the balls 61 of the bearing may be arranged in only one row in the axial direction as in this embodiment. Even when a plurality of 61 is provided in the axial direction, the size of the ball 61 can be reduced, and the axial length of the bearing 6 can be reduced. Therefore, the space on the outer peripheral side of the internal gear coupling portion 51 is enlarged in the axial direction. Therefore, the bearings 6 and the braking mechanism 7 can be arranged side by side along the axle direction.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A part of structure of the said embodiment is applied in the range which does not deviate from the meaning of this invention, The configuration of the embodiment can be appropriately changed and implemented.

  For example, although the example which equips 3 A of power transmission mechanisms with the multi-disk transmission mechanism was demonstrated in the said embodiment, as long as it is a compact transmission mechanism which can be accommodated in a limited space, it may be a thing of any system.

  Moreover, you may equip not a transmission mechanism but a deceleration mechanism. In this case, for example, using the double pinion type planetary gear mechanism, the internal gear 31 described in the embodiment is applied to the internal gear (ring gear) of the planetary gear mechanism to fix the carrier and reduce the sun gear. The speed reduction mechanism can also be configured as an input portion of the drive mechanism and an internal gear as an output portion of the speed reduction mechanism. In such a configuration, since the transmission mechanism shown in FIG. 1 is omitted, the axial dimension of the device can be greatly suppressed.

  Moreover, in the said embodiment, although the inner ring 62 of the bearing 6 is integrally formed in the connection member 5, and the connection member 5 and the inner ring 62 are made into the same member, the inner ring 62 is made into another member with the connection member 5, a connection member You may comprise so that it may connect with 5 and one. The cross-sectional shape of the connecting member 5 is also an example of the above embodiment and can be appropriately changed.

1 wheel 2 electric motor 3A power transmission mechanism for driving 3 speed change mechanism 4 casing (axle case)
Reference Signs List 5 connecting member 6 bearing 7 braking mechanism 11 wheel 12 hub 11 a of hub 11 convex portion 12 b of hub 12 hole portion of convex portion 12 a 21 output shaft of electric motor 2 output internal gear 31 bolt 51 internal gear of connecting member 5 Gear connecting portion 52 Wheel hub connecting portion 52 of connecting member 5 Disc-like portion 52b of wheel hub connecting portion 52 Boss of wheel hub connecting portion 52 Base portion of connecting member 5 61 Ball 62 Inner ring 63 Outer ring 71 Cylinder 72 Oil chamber 73 Piston 74 brake disc surface 75 brake pad 76 bolt 77, 78 seal ring 80 bracket 81 seal ring CL axle center IS body center side (inside of the vehicle)
OS Body side (body outside)

Claims (2)

A drive electric motor mounted in-wheel on a wheel of a wheel mounted on an electric vehicle, and an output internal tooth gear interposed between the wheel and the electric motor and connected to the wheel And a power transmission mechanism capable of changing the rotational speed, a bearing rotatably supporting the wheel on the vehicle body of the vehicle, and a braking mechanism for applying a braking force to the wheel. And
The electric motor, the power transmission mechanism, and the hub of the wheel are disposed in this order from the center side of the vehicle body to the side of the vehicle body along the axle direction of the wheel,
The output internal gear and the hub are adjacent to each other along the direction of the axle, and a connecting member is provided for power connecting the outer peripheral portion of the output internal gear to the hub.
The bearing and the braking mechanism are juxtaposed along the axle direction on the outer peripheral side of the connection member ,
The braking mechanism includes a cylinder mounted on the outer ring side of the bearing, a piston having a tip projecting according to a braking pressure inserted into the cylinder and supplied to the cylinder, and a vehicle center side of an inner ring of the bearing And a brake disc surface formed on the wheel. The wheel drive braking system according to claim 1, wherein an inner ring of the bearing is formed on the connecting member .

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