JP5926306B2 - Brake system for vehicles - Google Patents

Description

  The present invention relates to a vehicle brake system.

  In the drive system, a so-called in-wheel motor that drives a vehicle by housing a driving force source such as a motor in the wheel and driving the wheel by the driving force source is known. By housing the driving force source in the wheel, parts such as a gear device and a drive shaft are reduced, thereby improving weight, space efficiency, cost, maintainability, and the like.

  In a vehicle including an in-wheel motor, a disc brake that clamps a disc with a friction material using hydraulic pressure (hydraulic pressure) is used as a braking device (brake). As such a brake device, a device is disclosed in which a disc brake is integrally mounted on a rotating member fixed to a rotor of an electric motor (Patent Document 1).

Japanese Patent Laying-Open No. 2005-212656

  The prior art described in Patent Document 1 controls the braking force of a brake with hydraulic pressure. When the parking lock is provided in the brake device having such a configuration, it is necessary to control the parking lock by hydraulic pressure. In this case, no hydraulic pressure is generated when the hydraulic pressure source is in an inactive state, so that the locked state cannot be maintained when the vehicle system is stopped.

  On the other hand, the conventional wire parking lock which locks by a driver | operator's operation can also be used. In this case, the wire must be provided avoiding the in-wheel motor, which not only complicates the structure but also provides only a weak locking force.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a vehicle brake system that can maintain a parking lock state even when hydraulic pressure is not supplied.

According to one embodiment of the present invention, a motor disposed in or near the wheel, an input shaft that is rotationally driven by the motor, an output shaft that is disposed in parallel with the input shaft, an input shaft, and A plurality of disks fixed to the output shaft and arranged to overlap each other between the input shaft and the output shaft, and a plurality of disks are pressed against each other in the overlapping region where the plurality of disks overlap. And a pressing mechanism that transmits rotation from the shaft to the output shaft, and the pressing mechanism moves in the radial direction of the plurality of discs in the overlapping region so that rotation transmitted from the input shaft to the output shaft can be changed. a drive transmission, provided to the wheel drive device and a hydraulic piston for forward and backward movement on the basis of the hydraulic pressure in the hydraulic chamber formed in the housing, the arm connected to the hydraulic piston, collected eccentrically on the end of arm A cam being kicked, an elastic body, a piston is pressed by the cam, is formed in the housing, it is applied to a brake system comprising a locking groove cam is fitted, and a control unit for controlling the oil pressure condition, the. When the control unit increases the hydraulic pressure to press the disc with the piston to apply a braking force to the disc, and the control unit sets the hydraulic pressure to be equal to or higher than the predetermined hydraulic pressure, the hydraulic piston is located at the position where the cam and lock groove are fitted Even when the hydraulic pressure drops below the predetermined hydraulic pressure, the braking force to the disc is maintained by maintaining the engagement state between the cam and the lock groove, and the control unit increases the hydraulic pressure. The piston provided on the output shaft is pressed by the piston to give a braking force to the disc .

  According to the above aspect, the braking force to the disc can be maintained by controlling the hydraulic pressure and fitting the cam into the lock groove. As a result, the braking force can be maintained even when the hydraulic pressure is not supplied, for example, after the ignition is turned off, and can function as a parking lock.

It is explanatory drawing of a vehicle provided with the wheel drive device of embodiment of this invention. It is explanatory drawing of the wheel drive device of embodiment of this invention. It is explanatory drawing of the wheel drive device of embodiment of this invention. It is explanatory drawing of the wheel drive device of embodiment of this invention. It is explanatory drawing which shows the brake system of embodiment of this invention. It is explanatory drawing which shows the structure of the brake device of embodiment of this invention. It is explanatory drawing which shows the structure of the brake device of embodiment of this invention. It is explanatory drawing which shows the brake operation | movement of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram of a vehicle 4 including a wheel driving device 1 according to an embodiment of the present invention.

  The wheel drive device 1 according to the present embodiment is housed in a wheel 10 that constitutes the drive wheel 2 of the vehicle, and rotates the drive wheel 2 by the drive force of the motor 20 that is a drive force source. Let it run. The vehicle 4 is provided with a steering device 5 and controls the steering direction of the drive wheels 2. The wheel driving device 1 operates under the control of the control device 3 based on instructions such as operation of the steering device 5 by the driver, operation of the accelerator pedal 6, the brake pedal 7, the parking lock lever (or switch) 11, and the like. .

  The control device 3 sends an instruction to the hydraulic pressure control unit 9 to supply hydraulic pressure to the brake device 72 (see FIG. 2) provided in the wheel drive device 1 to generate a braking force on the vehicle. The hydraulic control unit 9 includes a hydraulic pump that generates hydraulic pressure by mechanical rotation of a gear or the like, an electric motor, or the like, and generates hydraulic pressure based on an instruction from the control device 3.

  Although the vehicle 4 is provided with four wheels, it is sufficient that at least two wheels are configured as the drive wheels 2.

  2 to 4 are explanatory views showing the configuration of the wheel drive device 1 of the present embodiment.

  2 to 4 set the horizontal x-axis, the vertical y-axis, and the z-axis orthogonal to the x-axis y-axis, and show cross-sectional views in the x-axis plane, the y-axis plane, and the z-axis plane, respectively. .

  The wheel drive device 1 includes a wheel 10, a motor 20, a speed change mechanism 30, and a speed reduction mechanism 40.

  The wheel 10 includes a substantially cylindrical rim portion 10 a that holds a tire, and a disk-shaped disc portion 10 b that is attached to a rotation-side hub 15 via bolts 16. A drive device such as a motor 20 accommodated in the housing 12 is housed inside the wheel 10. The housing 12 has a substantially cylindrical shape that is slightly smaller than the inner diameter of the rim portion 10 a of the wheel 10, and is connected to a suspension (not shown) of the vehicle 4.

  The motor 20 is configured as an axial gap motor in which disk-shaped stators 21 and 22 having coils and a disk-shaped rotor 23 having permanent magnets are arranged side by side in the rotation axis direction. The rotation of the rotor 23 that rotates when the motor 20 is driven is input to the speed change mechanism 30 from the input shaft 31 fixed to the rotor 23.

  The input shaft 31 extends from the motor 20 into the housing 12, and the end of the input shaft 31 is rotatably supported at the center of the hub 15 coupled to the disk portion 10b of the wheel 10 via a bearing 12a. .

  The speed change mechanism 30 is configured such that a disk-shaped primary disk 32 fixed to the input shaft 31 and a disk-shaped secondary disk 34 fixed to the output shaft 33 are brought into contact with each other by a pressing mechanism 35, whereby the input shaft 31. This is a friction drive transmission that transmits the rotation of the motor to the output shaft 33 so as to be variable.

  The speed reduction mechanism 40 includes an external gear output gear 33a provided on the output shaft 33 and an internal gear 14 meshing with the external gear output gear 33a, and the rotation output from the output shaft 33 is the internal gear. The speed is reduced by 14 and the reduced speed is transmitted to the wheel 10 via the hub 15.

  Next, each structure of the wheel drive device 1 will be described.

  The motor 20 is configured by sequentially arranging a stator 21, a rotor 23, and a stator 22 in the axial direction. The motor 20 has a substantially cylindrical shape whose outer periphery matches the inner diameter of the opening of the housing 12, and is fixed to the inner peripheral side of the housing 12.

  The rotor 23 is disposed between the stators 21 and 22 disposed with a gap in the axial direction, and rotates by the action of the magnetic field generated by these. Each of the stators 21 and 22 is provided with a plurality of coils in the circumferential direction. Each coil is wound around an axis parallel to the rotation axis of the motor 20. In the motor 20 of the present embodiment, the permanent magnet provided in the rotor 23 is configured as a ferrite magnet.

  The control device 3 rotates the rotor 23 by supplying current corresponding to the depression amount of the accelerator pedal 6 to the coils provided in the stators 21 and 22. As the rotor 23 rotates, the input shaft 31 rotates. The rotation of the input shaft 31 is input to the speed change mechanism 30.

  The transmission mechanism 30 includes a primary disk 32 fixed to the input shaft 31, a secondary disk 34 fixed to the output shaft 33, and a pressing mechanism 35.

  The primary disk 32 is configured by mounting two circular disks 32 a side by side in the axial direction of the input shaft, and rotates integrally with the input shaft 31. The two disks 32a are arranged at a predetermined interval. The outer peripheral end of the disk 32 a is disposed so as to be close to the output shaft 33.

  The secondary disk 34 is configured by a center disk 34 a and two side disks 34 b provided facing the both sides of the center disk 34 a arranged side by side in the axial direction of the output shaft 33, and integrated with the output shaft 33. Turns and turns. The center disk 34a and the side disk 34b are arranged at a predetermined interval. The outer peripheral ends of the center disk 34 a and the side disks 34 b are arranged so as to be close to the input shaft 31.

  The disk 32a of the primary disk 32 is disposed between the center disk 34a and the side disk 34b of the secondary disk 34. The primary disk 32 and the secondary disk 34 form a disk overlap region where a part of the disk overlaps between the input shaft 31 and the output shaft 33.

  In the disk overlap region, a gap is formed between the disk 32a of the primary disk 32 and the center disk 34a of the secondary disk 34 in a state where the pressing force by the pressing mechanism 35 does not act. In a state in which the pressing force by the pressing mechanism 35 is applied, the primary disk 32 and the secondary disk 34 are elastically deformed to come into contact with each other, and a torque transmission contact portion is formed.

  By forming a torque transmission contact portion between the primary disk 32 and the secondary disk 34, rotation is transmitted from the input shaft 31 to the output shaft 33. By moving the torque transmission contact portion in the radial direction of the primary disk 32 and the secondary disk 34 in the disk overlapping region, the rotation of the input shaft 31 can be transmitted to the output shaft 33 in a variable speed manner. In FIG. 3, an axis connection line O indicated by a thick dotted line connects the axis of the input shaft 31 and the output shaft 33 and is orthogonal to the input shaft 31 and the output shaft 33. The torque transmission contact portion is formed on the shaft connection line O.

  The pressing mechanism 35 includes a pressing roller mechanism 130, a disk clamping mechanism 131, a pressing force adjusting mechanism 132, and a sliding actuator 133.

  The pressing roller mechanism 130 includes a pressing roller 140, a holding portion 141, a pressing roller shaft 142, a guide block 149, a guide block 150, and a guide block shaft 151.

  The pair of pressing roller mechanisms 130 are arranged on both sides of the primary disk 32 and the secondary disk 34 and are attached to the guide block 149. The guide block 149 is attached between the two guide blocks 150 attached to the inner periphery of the housing 12 and is slidably attached to a plurality of guide block shafts 151 extending in the direction of the axis connection line O.

  As shown in FIG. 4, the disk clamp mechanism 131 includes a front clamp arm 167 and a rear clamp arm 168. The front clamp arm 167 and the rear clamp arm 168 are each slidably attached with a guide portion 146 on the lower side of the pressing roller mechanism 130. The front clamp arm 167 and the rear clamp arm 168 are moved in a direction in which the primary disk 32 and the secondary disk 34 are clamped with each other by the pressing force adjusting mechanism 132, thereby pressing the pressing roller 140 against the disk.

  The pressing force adjusting mechanism 132 moves the front clamp arm 167 and the rear clamp arm 168 in a direction to sandwich the primary disk 32 and the secondary disk 34 by the operation of the actuator 190. By operating the actuator 190 in response to a command signal from the control device 3, the pressing roller 140 is pressed against the disk side. Thereby, the primary disk 32 and the secondary disk 34 are elastically deformed and brought into contact with each other to form a torque transmission contact portion, and the rotation of the input shaft 31 is transmitted to the output shaft 33.

  The sliding actuator 133 includes an electric motor 134 and a sliding mechanism 135. The sliding actuator 135 is moved forward and backward by operating the electric motor 134 according to a command signal from the control device 3, and is connected to the sliding mechanism 135. The pressing roller mechanism 130 is moved along the axial connection line O. As a result, the pressing roller 140 of the pressing roller mechanism 130 is moved in the direction of the axis connection line O to form a torque transmission contact portion at a position corresponding to the target gear ratio.

  An external gear 33a is provided at the end of the output shaft 33 on the disk portion 10b side. The external gear output gear 33 a meshes with the internal gear 14 fixed to the hub 15 coupled to the wheel 10 to rotate the internal gear 14.

  The external tooth output gear 33a meshes with an idler gear 51 that is provided on the inner peripheral side of the internal gear 14 and is rotatably provided coaxially with the input shaft 31. The internal gear 14 and the idler gear 51 have the same rotation shaft, and there is an interval between the external gear 33a and the external gear 33a. The idler gear 51 is pivotally supported via a bearing 51 a so as to be rotatable with respect to the output shaft 33.

  Between the internal gear 14 and the idler gear 51, a pinion 61a having substantially the same shape as that of the external gear 33a is engaged with a position different from that of the external gear 33a. The pinion 61 a is provided on the disk portion 10 b side of the counter shaft 61.

  The external gear 33a of the output shaft 33 is provided at one point in the circumferential equal division point of the internal gear 14, and the pinion 61a of the counter shaft 61 is provided at another point in the circumferential equal division point of the internal gear 14. In the present embodiment, the external tooth output gear 33a and the pinion 61a are arranged in the diameter direction of the internal gear 14 with the input shaft 31 as the center, but more pinions 61a and counter shafts may be arranged.

  A bearing 17 is provided on the inner peripheral side of the housing 12 and on the disk portion 10b side, and the internal gear 14 is supported by the bearing 17 so as to be rotatable from the outer periphery. The internal gear 14 is fixed to the hub 15. The hub 15 is rotatably supported by the housing 12 via the internal gear 14 and the bearing 17. The disk portion 10 b of the wheel 10 is coupled to the hub 15 via a bolt 16.

  An oil seal 18 is provided between the hub 15 and the housing 12. The oil seal 18 prevents the lubricating oil from scattering from the bearing 17 and the like to the wheel 10 and the outside thereof.

  The secondary disk 34 fixed to the output shaft 33 is provided with a brake device 72. The brake device 72 imparts rotational resistance by sandwiching the center disk 34a and the two side disks 34b constituting the secondary disk 34, and brakes the rotation of the output shaft 33. A braking force is applied to the vehicle by braking the rotation of the output shaft 33.

  As will be described later, the brake device 72 uses the hydraulic pressure supplied from the hydraulic control unit 9 in accordance with an instruction from the driver, for example, an instruction from the control device 3 in accordance with an amount of depression of the brake pedal. To control.

  As described above, the wheel drive device 1 according to the present embodiment shifts the output of the motor 20 by the speed change mechanism 30, and the wheel 10 via the internal gear 14 provided on the inner side of the wheel 10 with the speed-changed rotation. It is the structure which is transmitted to. Thus, by transmitting the rotation to the wheel 10 by the internal gear 14, the rotation to the wheel 10 can be transmitted with a large reduction ratio, and the space in the inner diameter portion of the internal gear 14 is driven by the wheel. Since it can use for the component of the apparatus 1, the depth of a component can be formed flat, and the size and weight of the wheel drive device 1 can be reduced.

  Next, the structure of the brake system 8 of this embodiment is demonstrated.

  FIG. 5 is an explanatory diagram showing the brake system 8 of the present embodiment.

  The brake system 8 applies a braking force to the secondary disk 34 of the wheel drive device 1 by supplying hydraulic pressure from the hydraulic control unit 9 to the brake device 72 under the control of the control device 3.

  The control device 3 calculates the hydraulic pressure supplied to the brake device 72 so that the required braking force is obtained by the driver's depressing force of the brake pedal 7 or the operation of the parking lock lever 11, and the calculated hydraulic pressure is supplied to the hydraulic control unit. 9 is instructed. The hydraulic control unit 9 supplies hydraulic pressure to the brake device 72 based on the instruction.

  As will be described later, the braking force of the brake device 72 is controlled by supplying the brake force adjusting hydraulic pressure, and the fitting between the cam 270 and the lock groove 290 is released by supplying the return hydraulic pressure. The hydraulic control unit 9 is provided with a switching valve 9a, and the switching valve 9a switches between supplying the brake device 72 with a brake force adjusting hydraulic pressure or supplying a return hydraulic pressure.

  6 and 7 are explanatory views showing the configuration of the brake device 72 of the present embodiment. FIG. 6A is an explanatory diagram showing a configuration of the brake device 72 when not braked, and FIG. 6B is a cross-sectional view taken along line AA of FIG. FIG. 7 is an explanatory diagram showing a configuration of the brake device 72 during braking.

  The brake device 72 presses the center disk 34a and the side disk 34b of the secondary disk 34 sandwiched between the lining 351 and the intermediate lining 361 by moving the piston 280 housed in the housing 210 forward and backward by hydraulic pressure, A braking force is applied to the disk 34.

  The piston 280 is moved by a hydraulic piston 250 that moves forward and backward by the hydraulic pressure of the hydraulic oil supplied to the hydraulic chamber 221. An arm 260 is connected to the hydraulic piston 250, and a cam 270 is connected to the end of the arm 260. The piston 280 is pressed by the cam 270 moving forward and backward as the hydraulic piston 250 moves forward and backward.

  The piston 280 is provided with a pressing plate 310 and a disc spring 320. The pressing plate 310 is fitted into a recess formed in the piston 280 via a disc spring 320. When the pressing plate 310 is pressed by the cam 270, the disc spring 320 is compressed and the piston 280 moves forward. The lining 351 fixed to the piston 280 is pressed against the secondary disk 34 by the urging force generated by the compression of the disc spring 320, and a braking force is applied to the secondary disk 34.

  A pair of arms 260 is connected to the hydraulic piston 250. A guide rod 261 passes through the distal ends of the pair of arms 260, and the cam 270 is supported so as to be rotatable about the guide rod 261. The cam 270 has a substantially disc shape, and the guide rod 261 passes through a hole 271 formed at a position eccentric from the disc-shaped center of the cam 270.

  A hydraulic chamber 221 defined by a hydraulic chamber wall 225 is formed inside the housing 210. The hydraulic chamber 221 includes a brake force adjusting hydraulic chamber 222 and a return hydraulic chamber 223 with the hydraulic piston 250 as a boundary. The hydraulic piston 250 moves forward and backward in the hydraulic chamber 221 according to the hydraulic pressure of the supplied hydraulic oil. The hydraulic piston 250 is provided with a seal 251 that seals hydraulic oil. The brake force adjustment hydraulic pressure chamber 222 and the return hydraulic pressure chamber 223 communicate with a brake force adjustment hydraulic pressure supply port 230 and a return hydraulic pressure supply port 240, respectively. The hydraulic oil supplied from the hydraulic pressure control unit 9 is supplied to each oil chamber via the brake force adjusting hydraulic pressure supply port 230 and the return hydraulic pressure supply port 240, and the hydraulic pressure in each oil chamber is controlled.

  As shown in FIG. 6B, the interior of the housing 210 is formed with a substantially rectangular cavity 221a when cut along an AA plane orthogonal to the forward and backward direction of the hydraulic piston 250. In this embodiment, the hollow portion having a substantially rectangular cross section is used. However, since the hydraulic chamber 221 is generally a cylindrical shape that is easy to ensure liquid-tightness, the shape of the hollow portion 221a is the shape of the hydraulic chamber 221. You may make it match with a shape.

  A pair of bearing grooves 261a for supporting the guide rod 261 are formed on the inner wall surface in the vertical direction of the hollow portion 221a so as to face each other. The bearing groove 261a supports the guide rod 261 so as to be slidable in the forward / backward direction of the hydraulic piston 250.

  The hole 271 of the cam 270 is formed at a position eccentric from the disc-shaped center of the cam 270. The hole 271 is disposed on the moving direction side of the hydraulic piston 250 with respect to the disc-shaped center of the cam 270 and on the lower side in the vertical direction (on the lock groove 290 side) with respect to the disc-shaped center of the cam 270.

  In the hollow portion 221a, a lock groove 290 into which the cam 270 can be fitted is formed at the bottom of the cam 270 on the forward direction side.

  As shown in FIG. 7, the lock groove 290 is engaged with the cam 270 in a state where the hydraulic pressure of the brake force adjusting hydraulic chamber 222 is substantially maximum, and the movement of the cam 270 is locked, so that the braking state of the brake To maintain.

  By increasing the hydraulic pressure in the brake force adjusting hydraulic chamber 222, the hydraulic piston 250 moves forward in the direction in which the braking force is applied. The cam 270 advances in conjunction with the advance of the hydraulic piston 250 and presses the pressing plate 310 of the piston 280. As a result, the pressing plate 310 compresses the disc spring 320. The lining 351 of the piston 280 presses the secondary disk 34 by the urging force of the compressed disc spring 320.

  When the hydraulic pressure in the brake force adjusting hydraulic chamber 222 is lowered, the hydraulic piston 250 moves backward due to the compression reaction force of the disc spring. The cam 270 moves backward in conjunction with the backward movement of the hydraulic piston 250, and the force with which the piston 280 presses the pressing plate 310 decreases. Thereby, the force by which the lining 351 of the piston 280 presses the secondary disk 34 is released.

  In this manner, the braking force applied to the secondary disk 34 can be adjusted by adjusting the hydraulic pressure that the control device 3 supplies to the brake force adjusting hydraulic chamber 222 according to the depression amount of the brake pedal 7.

  The brake device 72 of the present embodiment can maintain the braking state of the secondary disk 34 regardless of the hydraulic pressure in the brake force adjusting hydraulic chamber 222.

  When the hydraulic pressure in the brake force adjusting hydraulic chamber 222 is larger than the predetermined hydraulic pressure (approximately the maximum value), the hydraulic piston 250 compresses the disc spring 320 and the cam 270 reaches the position of the lock groove 290. The cam 270 moves downward in the vertical direction while rotating the guide rod 261 counterclockwise, and engages with the lock groove 290.

  In this case, the cam 270 is fitted into the lock groove 290 as shown in FIG. When the cam 270 is fitted into the lock groove 290, the cam 270 is locked to the lock groove 290 due to the balance between the repulsive force of the disc spring 320 and the friction between the cam 270 and the lock groove 290. In a state where the cam 270 is fitted in the lock groove 290, the cam 270 does not move even if the hydraulic pressure in the brake force adjusting hydraulic chamber 222 is lowered, and the piston 280 pressed by the cam 270 maintains the pressing of the secondary disk 34. To do. In this way, the braking state is maintained even when the brake force adjusting hydraulic pressure is discharged.

  FIG. 8 is an explanatory diagram showing a brake operation in the brake device 72 of the present embodiment.

  In FIG. 8, the brake force adjustment hydraulic pressure of the brake force adjustment hydraulic chamber 222 is F, the spring reaction force of the disc spring 320 is Fsprg, the friction between the cam 270 and the inner wall of the housing 210 is f, the radius of the cam 270 is r, and the cam 270 The vertical distance (offset) between the center of the guide rod 261 and the center of the guide rod 261 is L, the horizontal distance (offset) between the center of the cam 270 and the center of the guide rod 261 is M, and the groove depth of the lock groove is Δx. And

  FIG. 8A shows a state where the brake device 72 applies a braking force.

  When the driver depresses the brake pedal 7 when the vehicle is in a driving state, the control device 3 applies a braking force to the wheel driving device 1.

  The control device 3 determines the required deceleration from the depression force of the brake pedal 7 by the driver, and controls the braking force by the wheel driving device 1 based on the determined required deceleration. Since the wheel drive device 1 includes the motor 20, a braking force is generated by causing the motor 20 to perform a regenerative operation. The braking force is also generated by applying a braking force to the secondary disk 34 by the brake device 72.

  The control device 3 gives priority to regenerating the motor 20 in order to improve the energy balance efficiency. Specifically, the control device 3 calculates a difference value obtained by subtracting the deceleration that can be generated by the braking force when the motor 20 is regenerated from the requested deceleration. If the calculated difference value is negative, the required deceleration can be satisfied by the deceleration due to regeneration of the motor 20, so that the control device 3 does not supply hydraulic pressure to the brake device 72 and does not control the brake device 72. Does not give power.

  If the calculated difference value is positive, further deceleration is required by the difference value, and therefore the deceleration of this difference value (hereinafter referred to as “brake deceleration”) is used as the braking force by the brake device 72. Is generated.

  In this case, the control device 3 calculates the hydraulic pressure supplied to the brake force adjusting hydraulic chamber 222 so as to obtain a braking force necessary for generating the brake deceleration, and instructs the hydraulic pressure control unit 9 of the calculated hydraulic pressure. To do. The hydraulic control unit 9 generates hydraulic pressure based on the instruction and supplies the hydraulic pressure to the brake force adjusting hydraulic chamber 222.

  At this time, by adjusting the brake force adjustment hydraulic pressure F so as to exceed the spring reaction force Fsprg, the cam 270 presses the piston 280 and applies a braking force to the secondary disk 34. Thus, the braking force can be controlled by adjusting the braking force adjustment hydraulic pressure F.

  When the brake force adjustment hydraulic pressure F increases and becomes equal to or greater than the predetermined brake force adjustment hydraulic pressure Fmax, that is, when the brake force adjustment hydraulic pressure F exceeds the predetermined braking force in the brake device 72, the cam 270 is locked as described below. A predetermined braking force is maintained by fitting in the groove 290. The predetermined braking force is, for example, the maximum braking force that can be generated by the brake device 72. Alternatively, any braking force required for the park lock may be used.

  When the cam 270 moves forward and reaches the position of the lock groove 290 (see FIG. 8B), the brake force adjustment hydraulic pressure F is applied to the center of the guide rod 261, whereas the spring reaction force Fsprg is the cam Add to the center of 270. At this time, a counterclockwise rotational moment represented by F × L is generated at the center of the guide rod 261, and the cam 270 rotates counterclockwise around the guide rod 261. As a result, the cam 270 moves to the lock groove 290 side, and the cam 270 is fitted into the lock groove 290 (FIG. 8C).

When the cam 270 is fitted into the lock groove 290, a force (Fsprg × (L−Δx)) for rotating the cam 270 counterclockwise by the spring reaction force Fsprg acting on the cam 270 and the guide rod 261 are The clockwise rotational moment (f × r) as the center is balanced as in the following equation (1). As a result, the cam 270 is locked in the lock groove 290.
Fsprg × (L−Δx) = f × r Equation 1

  In a state where the cam 270 is locked in the lock groove 290, a predetermined braking force is maintained on the secondary disk 34 by the piston 280.

  When the cam 270 is locked in the lock groove 290, the predetermined braking force is maintained even when the brake force adjustment hydraulic pressure F is reduced to zero, that is, even when the hydraulic pressure is discharged. Using this, the brake device 72 can be used for parking lock.

  For example, when the vehicle gives a parking lock instruction by operating the parking lock lever 11 while the vehicle is stopped, the control device 3 adjusts the brake force adjustment hydraulic pressure F to a predetermined brake force adjustment as described above. It controls so that it may become more than oil pressure Fmax. As a result, the cam 270 is locked in the lock groove 290. In this state, even when the vehicle control is stopped such as turning off the ignition key and the hydraulic pressure is no longer supplied to the brake device 72, the predetermined braking force is maintained.

  When it is no longer necessary to maintain the predetermined braking force, for example, when the driver gives an instruction to release the parking lock by operating the parking lock lever 11, the control device 3 supplies the return hydraulic pressure Fr to the return hydraulic chamber 223. Supply. By supplying the return hydraulic pressure Fr, a force for moving the hydraulic piston 250 in the backward direction is applied. This force is transmitted to the cam 270 via the arm 260.

In this case, with respect to the force (Fsprg × (L−Δx)) that causes the cam 270 to rotate counterclockwise by the spring reaction force Fsprg acting on the cam 270, the return hydraulic pressure Fr is applied to the guide rod 261 in the rotational direction. When the force F′r is applied, the force relationship is changed as in the following formula 2, and the cam 270 rotates clockwise (see FIG. 8D).
Fsprg × (L−Δx) <F′r × (r−L) Equation 2

  As a result, the cam 270 rotates clockwise around the guide rod 261, and the lock of the cam 270 to the lock groove 290 is released.

  When the lock between the cam 270 and the lock groove 290 is released, the control device 3 adjusts the brake force adjustment hydraulic pressure F as described with reference to FIG. The braking force can be controlled by pressing the secondary disk 34.

  As described above, the brake system of this embodiment includes the hydraulic piston 250 that moves forward and backward based on the hydraulic pressure of the hydraulic chamber 221 formed in the housing 210, the arm 260 that is connected to the hydraulic piston 250, and the arm 260. A cam 270 that is eccentrically attached to the end, a disc spring 320 that is an elastic body, a piston 280 that is pressed by the cam 270, a lock groove 290 that is formed in the housing 210 and into which the cam 270 is fitted, and a hydraulic chamber A control device 3 and a hydraulic control unit 9 as a control unit for controlling the hydraulic state of 221, and the control unit increases the hydraulic pressure so that the secondary disk 34 is pressed by the lining 351 provided in the piston 280, It gives braking force to the disc.

  In the brake system according to the present embodiment, in such a configuration, when the brake force adjustment hydraulic pressure F is equal to or higher than a predetermined hydraulic pressure, the hydraulic piston 250 moves forward to a position where the cam 270 and the lock groove 290 are fitted to each other. Even when the force adjustment hydraulic pressure is lower than the predetermined hydraulic pressure, the braking force applied to the secondary disk 34 is maintained by maintaining the fitting state between the cam 270 and the lock groove 290.

  With such a configuration, the brake system can generate a braking force in the wheel drive device 1 that drives the vehicle. Since the braking force applied to the secondary disk 34 is maintained by controlling the brake force adjustment hydraulic pressure to fit the cam 270 and the lock groove 290, the brake device 72 can function as a parking lock. Thereby, parking lock can be performed even when the hydraulic pressure is not supplied to the brake device 72, for example, after the ignition is turned off. This effect corresponds to claim 1.

  In the brake system of the present embodiment, the hydraulic chamber 221 is provided with a return hydraulic chamber 223 to which a return hydraulic pressure is supplied to urge the hydraulic piston 250 in the reverse direction. The fitting state with the lock groove 290 is released. With such a configuration, the fitted state can be easily released by hydraulic pressure, so that it can function as a parking lock with a simple configuration. This effect corresponds to claim 2.

  In the brake device 72 of the present embodiment, when the parking lock is instructed by the driver, the brake force adjustment hydraulic pressure is set to a predetermined hydraulic pressure or more and the cam 270 is fitted into the lock groove 290, so that the parking lock is performed according to the driver's instruction. It can be carried out. This effect corresponds to the third aspect.

  The brake device 72 according to the present embodiment includes a motor 20 disposed inside the wheel 10, an input shaft 31 that is driven to rotate by the motor 20 and disposed on the rotation center axis of the wheel 10, and is parallel to the input shaft 31. And a plurality of disks (primary disk 32, secondary disk) fixed to the input shaft 31 and the output shaft 33, respectively, and arranged to overlap each other between the input shaft 31 and the output shaft 33. Disk 34) and a pressing mechanism 35 that transmits rotation from the input shaft 31 to the output shaft 33 by pressing a plurality of disks against each other in the overlapping region where the disks overlap, and the pressing mechanism 35 is in the overlapping region. A wheel drive comprising: a speed change mechanism 30 as a friction drive transmission capable of shifting the rotation transmitted from the input shaft 31 to the output shaft 33 by moving in the radial direction of the disk. Sonaeraru to the device 1. The brake device 72 increases the brake force adjusting hydraulic pressure, thereby pressing the secondary disk 34 provided on the output shaft 33 by the lining provided on the piston to give a braking force.

  With such a configuration, the brake device 72 can be provided inside the wheel 10 of the vehicle, and the size of the wheel drive device 1 is not increased. Thereby, the size and weight of the wheel drive device 1 can be reduced. This effect corresponds to claim 4.

  The brake device 72 of the present embodiment acquires a required deceleration required for the vehicle, calculates a brake deceleration obtained by reducing a deceleration generated by regenerating the motor 20 among the required decelerations, The brake deceleration is generated by increasing the force adjusting hydraulic pressure and applying a braking force to the secondary disk 34. With such a configuration, priority can be given to generating deceleration by regeneration of the motor 20 during deceleration, and the efficiency of energy balance by regeneration can be improved. This effect corresponds to the fifth aspect.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  The brake device 72 of the present embodiment is configured to apply a braking force to the secondary disk 34 on the output side of the speed change mechanism 30 that is a friction drive transmission in the wheel drive device 1, but is not limited thereto. The present invention can also be applied to a so-called general disc brake that includes a brake disc that rotates together with a driving wheel or driven wheel of a vehicle and applies a braking force to the brake disc.

1 Wheel drive device 3 Control device (control unit)
7 Brake pedal 8 Brake system 9 Hydraulic control part 9a Switching valve 10 Wheel 20 Motor 30 Speed change mechanism (friction drive transmission)
31 Input shaft 32 Primary disk 33 Output shaft 34 Secondary disk 72 Brake device 210 Housing 222 Brake force adjusting hydraulic chamber 223 Return hydraulic chamber 250 Hydraulic piston 260 Arm 261 Guide rod 270 Cam 280 Piston 290 Lock groove 320 Disc spring 351 Lining

Claims (4)

A motor disposed inside or in the vicinity of the wheel, an input shaft that is rotationally driven by the motor, an output shaft that is disposed in parallel with the input shaft, and the input shaft and the output shaft, respectively. A plurality of disks arranged to overlap each other between the input shaft and the output shaft, and the input shafts by pressing the plurality of disks against each other in a polymerization region where the plurality of disks overlap. A pressing mechanism that transmits rotation from the input shaft to the output shaft by moving the pressing mechanism in the radial direction of the plurality of disks in the overlapping region. A friction drive transmission capable of shifting, and a wheel drive device comprising:
A hydraulic piston that moves forward and backward based on the hydraulic pressure of a hydraulic chamber formed in the housing;
An arm connected to the hydraulic piston;
A cam attached eccentrically to the end of the arm;
A piston pressed by the cam;
A controller that controls the state of the hydraulic pressure,
A lock groove is formed in the housing,
The controller raises the hydraulic pressure, thereby pressing the disc with the piston to give a braking force to the disc,
When the control unit sets the hydraulic pressure to be equal to or higher than a predetermined hydraulic pressure, the hydraulic piston moves forward to a position where the cam and the lock groove are fitted,
Even when the hydraulic pressure is lower than the predetermined hydraulic pressure, the braking force to the disk is maintained by maintaining the fitting state between the cam and the lock groove ,
The vehicular brake system , wherein the control unit raises the hydraulic pressure to press a disk provided on the output shaft by the piston to apply a braking force to the disk . The hydraulic chamber is provided with a return hydraulic chamber to which a return hydraulic pressure for urging the hydraulic piston in the reverse direction is supplied.
2. The vehicle brake system according to claim 1, wherein when the return hydraulic pressure is supplied by the control unit, a fitting state between the cam and the lock groove is released.   3. The vehicle according to claim 1, wherein when the parking lock is instructed by a driver, the control unit sets the hydraulic pressure to be equal to or higher than a predetermined hydraulic pressure and causes the cam to fit into the lock groove. Brake system. The controller is
Get the required deceleration required for the vehicle,
Of the required deceleration, calculate the brake deceleration by reducing the deceleration generated by regenerating the motor,
The vehicle brake system according to claim 1, wherein the brake deceleration is generated by increasing the hydraulic pressure and applying a braking force to the disc .

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