JP2007223430A - Brake device for in-wheel motor vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake device for an in-wheel motor vehicle capable of generating a braking force even if hydraulic pressure outputted from a hydraulic pump drops. <P>SOLUTION: The brake device for the in-wheel motor vehicle having a motor 60 for rotating a wheel in a wheel comprises a hydraulic pump 90 which is connected to an output shaft of the motor and operated by the rotational output of the motor, a friction member 52 working on the wheel, a hydraulic cylinder 55 communicated with the hydraulic pump, and a piston provided in the hydraulic cylinder for pressing the friction member 52 against the wheel by the effect of the hydraulic pressure led into the hydraulic cylinder, and further comprises a hydraulic brake mechanism for giving the braking force to the wheel by the pressure of the piston on the friction member, a hydraulic pressure control means (410, etc.) for controlling the hydraulic pressure led into the hydraulic cylinder, and a lock mechanism 700 which is provided at the hydraulic brake mechanism to lock the piston while pressing the friction member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brake device for an in-wheel motor vehicle equipped with a motor for rotating the wheel in the wheel.

Conventionally, a mechanical brake mechanism as a parking brake mechanism is provided together with a hydraulic brake mechanism operated by hydraulic pressure from a master cylinder, and a camshaft having a cam groove is provided in a caliper in the brake device. Is known to perform a braking action by mechanically pushing a friction pad by driving a driven rod engaged with the cam groove and rotating a brake lever (see, for example, Patent Document 1). ).
JP-A-2-29509

  In recent years, in-wheel motor vehicles have been developed that include a motor for rotating the wheel in the wheel. In this in-wheel motor vehicle, a configuration is useful in which the motor not only functions as a wheel drive source but also functions as a brake hydraulic pressure generation source in cooperation with the hydraulic pump.

  However, in such a configuration, in a low vehicle speed range in which the rotational output of the motor decreases, the hydraulic pressure that can be output by the hydraulic pump decreases accordingly, and thus there is a problem that a braking force necessary for stopping the vehicle cannot be sufficiently obtained.

  Therefore, an object of the present invention is to provide a brake device for an in-wheel motor vehicle that can generate a necessary braking force even when the hydraulic pressure output from the hydraulic pump decreases.

In order to achieve the above object, a first invention provides a brake device for an in-wheel motor vehicle including a motor for rotating the wheel in the wheel.
A hydraulic pump connected to the output shaft of the motor and operated by the rotational output of the motor;
A friction member that acts on the wheel, a hydraulic cylinder that communicates with the hydraulic pump, and a piston that is provided in the hydraulic cylinder and that presses the friction member against the wheel by the action of hydraulic pressure guided into the hydraulic cylinder; A hydraulic brake mechanism that applies a braking force to a wheel by a pressing force of a piston against the friction member;
Hydraulic control means for controlling the hydraulic pressure introduced into the hydraulic cylinder;
A locking mechanism that is provided to the hydraulic brake mechanism and locks the piston while pressing the friction member.

The second invention relates to the first invention,
The locking mechanism is
A groove formed in the outer peripheral surface of the piston,
It has a locking part that fits into the groove part and locks the piston, and is operated to enter or exit from the hydraulic cylinder through a hole formed in the peripheral wall of the hydraulic cylinder, A locking member in which the locking portion is fitted into the groove portion at the entry position to form a locked state of the piston, and the locking portion is separated from the groove portion at the retracted position to form an unlocked state of the piston. Including
In the operating state of the locking mechanism, a state is formed in which the locking member is biased toward the entry position, and when the piston reaches the lock position, the locking portion is fitted into the groove portion. The locked state is realized. Thereby, a lock mechanism is realizable with a simple structure.

The third invention relates to the first or second invention,
The hydraulic brake mechanism further includes a second piston using the piston as a first piston,
The second piston is movable in the same direction as the first piston, and is connected to the first piston via an elastic body that can contract along the moving direction,
When the first piston is in the locked position, the second piston presses the friction member by the action of the repulsive force of the elastic body. As a result, an appropriate braking force can be generated in a locked state of the first piston in a manner that is not easily affected by the component accuracy.

The fourth invention relates to the first to third inventions,
The lock mechanism is actuated at a stage before the vehicle stops. As a result, the vehicle can be stopped by the braking force generated when the piston is locked.

The fifth invention relates to the first to fourth inventions,
The lock mechanism is maintained in an operating state when the vehicle is stopped. Thereby, the stop of the vehicle can be maintained by the braking force generated in the locked state of the piston.

The sixth invention relates to the first to fifth inventions,
The lock mechanism is released from the operating state when the vehicle starts. As a result, it is possible to ensure appropriate acceleration without being affected by the lock mechanism when the vehicle starts.

In a seventh invention according to the first to sixth inventions,
The piston locking position is set before the maximum movement position in the movement stroke of the piston. Accordingly, it is possible to generate a braking force larger than the braking force generated in the locked state of the piston when the lock mechanism is not operated, and it is possible to cope with emergency braking or the like.

The eighth invention relates to the first to seventh inventions,
The lock mechanism is prohibited from operating when a vehicle speed is equal to or higher than a predetermined value and an operation of a brake pedal is detected. This prevents the piston from being locked in a scene where a braking force greater than the braking force generated in the piston locked state is required, such as emergency braking.

  ADVANTAGE OF THE INVENTION According to this invention, the brake device for in-wheel motor vehicles which can generate | occur | produce a required braking force even when the hydraulic pressure which a hydraulic pump outputs falls can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a main part of a wheel to which a first embodiment of a brake device for an in-wheel motor vehicle according to the present invention is applied. In the following description, one wheel will be described, but the other wheels may have the same configuration unless otherwise specified.

  In the present specification and the appended claims, the term “in the wheel” means a substantially cylindrical space surrounded by the rim inner peripheral surface 10 a of the wheel 10. However, the expression that a part is arranged in the wheel does not necessarily mean that the whole part is arranged in the wheel, and does not exclude a configuration that partially protrudes from the wheel.

  In an in-wheel motor vehicle, as shown in FIG. 1, a driving motor 60 and a planetary gear 80 are disposed in the wheel.

  Motor 60 includes a stator core 61, a stator coil 62, and a rotor 63. The stator core 61 is fixed to the case 32. The stator coil 62 is wound around the stator core 61. When motor 60 is a three-phase motor, stator coil 62 includes a U-phase coil, a V-phase coil, and a W-phase coil. The rotor 63 is disposed on the inner peripheral side of the stator core 61 and the stator coil 62.

  The planetary gear 80 constitutes a speed reduction mechanism for the rotation of the motor 60 and includes a sun gear shaft 81, a sun gear 82, a pinion gear 83, a planetary carrier 84, a ring gear 85, and a pin 86.

  Sun gear shaft 81 is connected to rotor 63 of motor 60. The sun gear shaft 81 is rotatably supported by bearings 73 and 74. The sun gear 82 is connected to the sun gear shaft 81. The pinion gear 83 meshes with the sun gear 82 and is rotatably supported by a bearing 77 disposed on the outer periphery of the pin 86. The planetary carrier 84 is connected to the pinion gear 83 and is splined to the shaft 110. Planetary carrier 84 is rotatably supported by bearing 76. The ring gear 85 is fixed to the case 32. When the rotor 63 of the motor 60 rotates, the pinion gear 83 revolves around the sun gear 82 while rotating. Due to this rotation, the rotation of the rotor 63 of the motor 60 is decelerated and transmitted to the shaft 110 via the planetary gear 80.

  The present invention does not specify the configuration of the motor 60 or the speed reduction mechanism, and can be applied to any configuration of the motor 60 or speed reduction mechanism. For example, the motor does not need to be an inner rotor type motor as shown, and may be an outer rotor type motor. Further, the rotation output of the motor 60 may be output via a speed change mechanism including a planetary gear unit, for example.

  The shaft 110 forms an axle, is spline-fitted to the wheel hub 20 and the planetary carrier 84, and rotates with the rotation output of the motor 60. An oil passage 111 and an oil hole 112 are formed inside the shaft 110. An oil pump 90 is disposed at the end of the shaft 110 (the end inside the vehicle). An input shaft (rotary shaft) of the oil pump 90 is connected to the shaft 110 so as not to rotate. Note that the input shaft of the oil pump 90 may be integrated with the shaft 110.

  The oil pump 90 pumps up the oil accumulated in the oil reservoir 130 through the oil passage 120, and supplies the pumped oil to the oil passage 111. Oil in the oil passage 111 is supplied to the planetary gear 80 through the oil hole 112 by centrifugal force when the shaft 110 rotates. For example, in the illustrated example, the oil passage 121 is provided inside the pin 86 of the planetary gear 80. Thereby, cooling and lubrication of the planetary gear 80 are realized. The oil thus supplied to the planetary gear 80 is returned to the oil reservoir 130. Thus, in the present embodiment, an oil circulation mechanism that circulates oil in the motor 60 using the rotation output of the motor 60 is configured.

  The present invention does not particularly specify the details of the oil circulation mechanism, and any oil pump configuration or circulation path configuration may be used as long as it is a mechanism that circulates oil in the motor 60 using the rotation output of the motor 60. May be anything. For example, in the illustrated example, the oil pump 90 is a gear pump, but may be any type of gear pump such as an external gear pump, an internal gear pump (with or without crescent), and a vane pump. Other types of pumps may be used.

  Ball joints 140 and 150 are fixed to the case 32. The upper arm 170 has one end connected to the ball joint 140 and the other end fixed to the vehicle body 200. Lower arm 180 has one end connected to ball joint 150 and the other end fixed to the vehicle body. Upper arm 170 and lower arm 180 are fixed to the vehicle body so that the other ends can freely rotate in the direction of arrow 6. A spring 190 is provided between the vehicle body and the lower arm 180. Thereby, the wheel is suspended from the vehicle body. Note that the present invention is not particularly limited to the oil suspension mechanism, and is not limited to the multi-link type suspension shown in the figure, and other types of suspensions such as a strut suspension may be adopted.

  In an in-wheel motor vehicle, as shown in FIG. 1, a hydraulic brake mechanism is disposed in the wheel. The hydraulic brake mechanism in the illustrated example includes a disc brake device and includes a brake rotor 40 and a brake caliper 50. Although the present invention depends on the space in the wheel, the present invention can be applied to other types of hydraulic brake mechanisms such as a drum brake as long as it is a hydraulic brake mechanism.

  The brake rotor 40 is arranged so that the inner peripheral end is fixed to the outer peripheral end of the wheel hub 20 by screws 3 and 4 and the outer peripheral end passes through the brake caliper 50. The brake caliper 50 is fixed to the case 32. The brake caliper 50 includes a piston 51, a wheel cylinder 55, and brake pads 52 and 53. The brake pads 52 and 53 sandwich the outer peripheral end of the brake rotor 40.

  The hydraulic brake mechanism according to this embodiment includes a lock mechanism 700 that operates to lock the movement of the piston 51 at a predetermined position. The configuration and operation of the lock mechanism 700 will be described later with reference to FIG.

  When the brake oil is supplied to the wheel cylinder 55, the piston 51 moves to the right side of the page and pushes the brake pad 52 to the right side of the page. When the brake pad 52 is moved to the right side of the drawing by the piston 51, the brake pad 53 is moved to the left side of the drawing in response. As a result, the brake pads 52 and 53 sandwich the outer peripheral end of the brake rotor 40 and the wheel is braked.

  The hydraulic brake mechanism according to the present embodiment is configured to operate using the oil pump 90 as a hydraulic pressure generation source. Specifically, an oil passage 300 is set between the wheel cylinder 55 and the discharge port of the oil pump 90. The oil passage 300 may be communicated with the wheel cylinder 55 via a brake hose or the like as illustrated. This makes it possible to apply braking force to the wheels using the oil used in the oil circulation mechanism for cooling and lubricating the planetary gear 80. Further, since the hydraulic pressure necessary for generating the braking force is generated using the oil pump 90 for the oil circulation mechanism, it is possible to apply the braking force to the wheels without setting a new pump. . That is, by sharing the oil pump 90 between the oil circulation mechanism and the hydraulic brake mechanism, it is possible to set the hydraulic pressure generation source of the hydraulic brake mechanism in the wheel by efficiently using the limited space in the wheel. .

  The oil passage 300 is provided with a cooling cut valve 400, a pressure increasing linear valve 410, and a pressure reducing linear valve 420 (see FIG. 2), which will be described later. In the illustrated example, the unit including the cooling cut valve 400 (not visible in the view of FIG. 1), the pressure increasing linear valve 410 and the pressure reducing linear valve 420 is disposed adjacent to the radially outer side of the oil pump 90. However, it may be disposed adjacent to the inside of the vehicle of the oil pump 90, or may be configured as an integral unit including the oil pump 90. A check valve 310 may also be provided in the oil passage 300. The check valve 310 is a one-way valve that allows only an oil flow from the oil pump 90 toward the wheel cylinder 55.

  FIG. 2 is a diagram showing a main circuit of the brake device for the in-wheel motor vehicle of the present embodiment. As shown in FIG. 2, the discharge port of the oil pump 90 is connected to the oil passage 111 via the cooling cut valve 400. The cooling cut valve 400 is a normally open valve that is normally open. When the cooling cut valve 400 is open, the oil supplied from the discharge port of the oil pump 90 is used for cooling the motor 60 or lubricating the planetary gear 80 as described above.

  The discharge port of the oil pump 90 is connected to the wheel cylinder 55 of the brake caliper 50 of the wheel via the pressure increasing linear valve 410 by the oil passage 300. The pressure-increasing linear valve 410 is a normally closed valve that is normally closed. The pressure-increasing linear valve 410 is a linear control valve that increases the opening according to the magnitude of the drive signal when a drive signal is supplied from the control device 500 described later. Therefore, the amount of brake fluid flowing into the wheel cylinder 55 can be controlled linearly based on the drive current supplied to the pressure increasing linear valve 410. Thereby, the hydraulic pressure of the wheel cylinder 55 is increased in proportion to the increase amount of the opening degree of the pressure increasing linear valve 410.

  A pressure reducing linear valve 420 is connected between the pressure increasing linear valve 410 and the wheel cylinder 55. The pressure reducing linear valve 420 connects the wheel cylinder 55 and the oil reservoir (reservoir tank) 130. The pressure-reducing linear valve 420 is a normally closed valve that is normally closed. The pressure-reducing linear valve 420 is opened mainly to reduce the hydraulic pressure of the wheel cylinder 55.

  An oil pressure sensor 430 is provided in front of the wheel cylinder 55. The oil pressure sensor 430 is provided to detect the oil pressure (wheel cylinder pressure) in the wheel cylinder 55. A hydraulic pressure sensor 432 is provided between the oil pump 90 and the pressure increasing linear valve 410. The oil pressure sensor 432 is provided to detect the oil pressure (pump pressure) generated by the oil pump 90.

  FIG. 3 is a functional block diagram of the control device 500 for the brake device for the in-wheel motor vehicle of this embodiment. The control device 500 is configured as a microcomputer including a CPU, a ROM, a RAM, and the like connected to each other via a bus (not shown). The ROM stores programs and data executed by the CPU.

  The control device 500 includes various control devices such as an ECU for controlling the rotational drive of the motor 60, hydraulic sensors 430 and 432, and brake operation via an appropriate bus such as a CAN (Controller Area Network) or a high-speed communication bus. Various sensors such as the amount detection means 600, the wheel speed sensor 610, the accelerator opening sensor 620, and the like are connected. In addition, a cooling cut valve 400, a pressure increasing linear valve 410, and a pressure reducing linear valve 420, which are components to be controlled, are electrically connected to the control device 500.

  The brake operation amount detection means 600 may be a stroke sensor that outputs a signal corresponding to the operation amount (operation stroke) of the brake pedal, or a pedaling force sensor that outputs a signal corresponding to the brake pedaling force. Alternatively, in the case of a configuration having a master cylinder, the brake operation amount detection means 600 may be a master pressure sensor that outputs a signal corresponding to the master cylinder pressure. When a plurality of sensors (for example, a stroke sensor and a master pressure sensor) are provided, the brake operation amount detection means 600 may determine the brake operation amount based on the majority rule from these signals. Thereby, even when an abnormality occurs in a part of the stroke sensor, the master pressure sensor, or the like, the brake operation amount can be properly detected.

  As shown in FIG. 3, the control device 500 includes a brake operation determination unit 510 and a brake operation time control unit 530.

  The brake operation determination unit 510 detects whether or not the brake pedal is operated based on the detection result of the brake operation amount detection means 600.

  The brake operation control unit 530 operates when it is determined that the brake pedal is operated as a result of the determination by the brake operation determination unit 510. When it is determined that the brake pedal has been operated, the normal travel time control unit 520 closes the cooling cut valve 400. When the cooling cut valve 400 is closed, the oil discharged from the discharge port of the oil pump 90 can be supplied to the wheel cylinder 55 of the brake caliper 50 of the wheel through the oil passage 300.

  Thereafter, the brake operation control unit 530 controls the open / close state of the pressure increasing linear valve 410 and the pressure reducing linear valve 420 in the same manner as in the normal brake control until the operation of the brake pedal is finished, and A braking force corresponding to the operation amount is generated. That is, the brake operation control unit 530 adjusts the opening degree of the pressure increasing linear valve 410 and the pressure reducing linear valve 420 to control the wheel cylinder pressure to an arbitrary hydraulic pressure.

  Thus, according to the present embodiment, normal brake control can be realized by using the hydraulic pressure generated by the oil pump 90 to generate the wheel cylinder pressure corresponding to the brake operation amount. In addition, when a tendency of wheel locking occurs during normal brake control, the function of the antilock brake system (ABS) is increased or decreased by increasing or decreasing the wheel cylinder pressure of each wheel so that the slip ratio of the wheel does not exceed a predetermined value. Can be realized. Furthermore, the function of traction control (TRC), vehicle attitude control (VSC), and other brake controls can be realized by appropriately controlling the wheel cylinder pressure of each wheel in response to a request for automatic brake control.

  In this embodiment, as described above, the oil pump 90 used in the oil circulation mechanism is used as a hydraulic pressure generation source of the hydraulic brake mechanism, so that the pump system (pump of the brake actuator normally used as the hydraulic pressure generation source) , Motors and accumulators) can be abolished. However, the present invention does not completely exclude the configuration for setting this type of pump system. For example, an accumulator that stores high-pressure brake oil discharged from the oil pump 90 includes the oil pump 90 and the pressure-increasing linear valve 410. May be provided.

  FIG. 4 is a diagram schematically showing a main cross section of a hydraulic brake mechanism including a lock mechanism 700 according to this embodiment. FIG. 4 (A) shows an unlocked state of the piston 51, and FIG. The locked state of the piston 51 is shown. 4 corresponds to a partial view of the portion X in FIG. 1, and a part of the configuration outside the vehicle (configuration on the brake pad 53 side, for example, a claw portion of the brake caliper 50) is omitted in the drawing. Also, the back metal and shim are omitted in the drawing for the configuration of the brake pad 52 inside the vehicle.

  In the example shown in FIG. 4, the lock mechanism 700 includes an annular groove 51 a that is recessed in the outer peripheral surface of the piston 51, and a locking member 710 that fits into the annular groove 51 a and locks the movement of the piston 51. . An annular seal 706 is provided on the outer peripheral surface of the piston 51. As a result, the piston 51 can move (slid) along the piston moving direction Y while maintaining a liquid-tight state in the wheel cylinder 55.

  The locking member 710 is realized by a magnetic plunger that is electromagnetically operated by a solenoid 714. The locking member 710 is provided in the radial direction of the wheel cylinder 55 and is operated to enter or leave the wheel cylinder 55 through a hole 55 a formed in the peripheral wall of the wheel cylinder 55. At the entry position, the distal end portion 712 (locking portion) of the locking member 710 is fitted into the annular groove 51a, and the locked state of the piston 51 is formed. Further, at the retracted position, the distal end portion 712 of the locking member 710 is separated from the annular groove 51a, and the unlocked state of the piston 51 is formed.

  As shown in FIG. 4, the locking member 710 is biased toward the entry position by a spring 716. When the solenoid 714 is energized, the locking member 710 is attracted to the retracted position against the force of the spring 716, and the unlocked state of the piston 51 as shown in FIG. 4A is formed. When the energization of the solenoid 714 is released, the locking member 710 is biased toward the entry position by the spring 716. In this state, when the piston 51 moves in this state and the position of the annular groove 51a corresponds to the position of the hole 55a (position of the locking member 710) in the piston movement direction Y, the piston 51 moves toward the entry position. The biased locking member 710 fits into the annular groove 51a. Thereby, the locked state of the piston 51 as shown in FIG.

  In such a configuration, when the solenoid 714 is energized, the locking member 710 is attracted to the retracted position, so that the piston 51 moves and the position of the annular groove 51a corresponds to the position of the hole 55a. Even in this case, the locked state of the piston 51 is not realized. Further, even when the solenoid 714 is not energized (that is, even when the lock mechanism 700 is activated), the piston 51 does not move unless the piston 51 moves and the positions of the annular groove 51a and the hole 55a correspond to each other. The locked state is not realized.

  In this embodiment, the piston 51 is locked at a position where the brake pad 52 is pressed, so that a braking force is generated when the piston 51 is in a locked state. Hereinafter, the braking force generated when the piston 51 is in the locked state is also referred to as “locking braking force”. The wheel cylinder pressure when the piston 51 is in the lock position is referred to as “lock position cylinder pressure”.

  The lock position of the piston 51 (the position of the hole 55a) is set so that it can be stopped by the braking force at the time of locking or can be maintained. That is, the lock position of the piston 51 is determined so that the braking force at the time of locking corresponds to a braking force necessary for stopping or a braking force capable of maintaining the stopped state (hereinafter referred to as “stop braking force”). The

  Once the locked state of the piston 51 is realized, the brake pads 52 and 53 press and hold the outer peripheral end of the brake rotor 40 until the solenoid 714 is energized and the locked state is released. The state in which the hour braking force (stop braking force) is generated is maintained. This state is maintained irrespective of the hydraulic pressure in the wheel cylinder 55. That is, even when the hydraulic pressure in the wheel cylinder 55 is lowered, a state where a constant braking force is generated is maintained unless the locked state is released.

  FIG. 5 is a diagram illustrating a braking force supplement / maintenance function realized by the lock mechanism 700 of the present embodiment.

  In FIG. 5, the relationship between the braking force that can be generated by the pump hydraulic pressure generated by the oil pump 90 and the vehicle speed (V) is indicated by a solid line, and the stopping braking force is indicated by a broken line. As shown in FIG. 5, the pump hydraulic pressure (or pump discharge amount) has a relationship that is substantially proportional to the vehicle speed (V). That is, the pump hydraulic pressure depends on the rotational speed of the motor 60 (or the rotational speed of the motor 60). This is because the oil pump 90 is operated by the rotational output of the motor 60 as described above. For this reason, in the low vehicle speed region where the rotational output of the motor 60 is low, the pump hydraulic pressure (or the amount of oil that can be sucked) that can be generated becomes insufficient as the rotational output of the motor 60 decreases. There is a risk that the braking force cannot be obtained. That is, the braking force that can be generated from the pump hydraulic pressure is less than the stopping braking force, and it is difficult to realize or maintain the stopped state with the pump hydraulic pressure alone.

  On the other hand, in the present embodiment, even when the pump hydraulic pressure is reduced as the rotational output of the motor 60 is reduced, the locked state of the piston 51 by the lock mechanism 700 is formed, and the stopping braking force (braking force at the time of locking). Can be generated. For example, as shown in FIG. 5B, by locking the piston 51 at an appropriate lock position where the stopping braking force can be generated, the stopping braking force can be reduced even in a low vehicle speed region where the vehicle speed is less than Vmin. Can be secured. As a result, even in a low vehicle speed region where the rotational output of the motor 60 is low, it is possible to realize the stopped state and to maintain the stopped state.

  FIG. 6 is a flowchart showing an embodiment of main processing realized by the control device 500 (brake operation time control unit 530) according to the present embodiment in the process from the stop state to the next stop state.

  Referring to FIG. 6, in the stop state, for example, the solenoid 714 is not energized until the depression of the accelerator pedal is detected based on the output signal of the accelerator opening sensor 620 (until YES determination in step 110). A state is formed (step 100). That is, in the stopped state, the operating state of the lock mechanism 700 is maintained, so that the locked state of the piston 51 is maintained, and as a result, the generation state of the braking force during braking (stopped braking force) is maintained.

  When depression of the accelerator pedal is detected (YES in step 110), the solenoid 714 is energized for a predetermined time (step 120). As a result, the locking member 710 is pulled out of the annular groove 51a of the piston 51 and sucked to the retracted position, and the locked state of the piston 51 is released. Since the hydraulic pressure in the wheel cylinder 55 is reduced as will be described later in the stopped state, the piston 51 is separated from the brake pad 52 after the locking member 710 comes out of the annular groove 51a of the piston 51 (see FIG. Move to the left of 4). That is, when the locking member 710 comes out of the annular groove 51a of the piston 51, the piston 51 moves to the left side of FIG. When the locked state is released while the hydraulic pressure in the wheel cylinder 55 is low, the brake pads 52 and 53 are not pressed against the outer peripheral end of the brake rotor 40, and the brake rotor 40 can freely rotate. As a result, the vehicle can start and run according to depression of the accelerator pedal.

  In addition, once the locking member 710 comes out of the annular groove 51a of the piston 51, even if the solenoid 714 is de-energized thereafter, the piston 51 is moved by the brake operation and the positions of the annular groove 51a and the hole 55a do not correspond. As long as the piston 51 is locked, the locked state is not realized. For this reason, the energization to the solenoid 714 in this step 120 may be executed for a certain period of time.

  Thereafter, when depression of the brake pedal is detected by the brake operation determination unit 510 (YES determination in step 130), first, energization to the solenoid 714 is started and maintained (step 140). Further, the cooling cut valve 400 is closed. When the cooling cut valve 400 is closed, the pump hydraulic pressure generated by the oil pump 90 can be supplied to the wheel cylinder 55 through the oil passage 300.

  In step 150, the target braking force is calculated based on the brake operation amount (for example, brake pedal force) obtained from the brake operation amount detection means 600.

  In step 160, the target braking hydraulic pressure is calculated based on the calculated target braking force.

  In step 170, the flow rate of the control valve (the pressure-increasing linear valve 410 and the pressure-reducing linear valve 420) corresponding to the vehicle speed is estimated (calculated) based on the vehicle speed (or the rotational speed of the motor 60, etc.).

  In step 180, the target valve opening of the control valve is calculated based on the calculated target brake hydraulic pressure and the estimated flow rate of the control valve. In other words, a valve opening at which the target braking hydraulic pressure is realized by the oil supplied at the estimated flow rate of the control valve is calculated as the target valve opening.

  In step 190, a drive current (solenoid current value) corresponding to the target valve opening is determined. The drive current determined in this way is supplied to the control valve. When a drive signal is supplied from the control device 500, an opening degree is realized in the control valve according to the magnitude of the drive signal.

  The normal brake control from step 150 to step 190 is repeatedly executed until the vehicle speed becomes lower than the predetermined threshold A (until the determination of YES in step 200). That is, in the vehicle speed region where the vehicle speed is equal to or higher than the predetermined threshold A, a sufficiently large rotational output of the motor 60 can be secured, so that the braking force is covered only by the pump hydraulic pressure. A method for setting the predetermined threshold A will be described later.

Thereafter, when the vehicle speed becomes lower than the predetermined threshold A (YES determination at step 200), the braking / driving force adjustment control by the brake operation time control unit 530 (processing from step 210 to step 240) until the vehicle speed becomes lower than the predetermined threshold B. Is repeatedly executed. The predetermined threshold B is a vehicle speed limit value Vmin (see FIG. 5) at which the stopping braking force cannot be secured.
Threshold B = Vmin + solenoid response time Ts × vehicle maximum deceleration may be used.

  According to the braking / driving force adjustment control, the wheel cylinder pressure is controlled to be a target parking brake hydraulic pressure that is larger than the lock position cylinder pressure regardless of the brake depression force, and the braking force is controlled by the wheel cylinder pressure. As a result, a braking force corresponding to the brake depression force is realized.

  Specifically, when the vehicle speed becomes smaller than the predetermined threshold A, it is determined whether or not the wheel cylinder pressure controlled according to the brake pedal force is smaller than the target parking brake hydraulic pressure (step 210). If the wheel cylinder pressure is greater than the target parking brake hydraulic pressure, the routine returns to step 150. If the wheel cylinder pressure is smaller than the target parking brake oil pressure, the target brake oil pressure is set to the target parking brake oil pressure (step 220). That is, the target braking hydraulic pressure is corrected so that target braking hydraulic pressure = target parking braking hydraulic pressure.

  In step 230, the target driving force is calculated in order to compensate for the correction of the target brake hydraulic pressure in step 220. That is, target driving force = target braking force−target parking braking force (where target parking braking force = braking force corresponding to the target parking braking hydraulic pressure). In step 240, a current that generates the target driving force is supplied to the motor 60. As a result, a braking force corresponding to the brake depression force is generated by canceling the braking / driving force, so that it is possible to realize a brake control that does not make the driver feel uncomfortable.

  When the vehicle speed becomes smaller than the predetermined threshold B (YES in step 250), the energization to the solenoid 714 is stopped (step 260). In the braking / driving force adjustment control, as described above, the wheel cylinder pressure is controlled to be maintained at the target parking brake hydraulic pressure that is larger than the lock position cylinder pressure. However, as described above with reference to FIG. When the value is smaller than the value Vmin (see FIG. 5), it becomes impossible to generate the lock position cylinder pressure by the pump hydraulic pressure as described above. Accordingly, when the vehicle speed becomes lower than the predetermined threshold B, energization to the solenoid 714 is immediately stopped so that the above-described locked state of the piston 51 is realized. Thereby, since the piston 51 can be locked at the lock position, even when the vehicle speed is smaller than the limit value Vmin and the lock position cylinder pressure cannot be generated by the pump hydraulic pressure as described above, It is possible to obtain a stopping braking force by generating a braking force when locked.

  In step 220, the wheel cylinder pressure is controlled to be a target parking brake hydraulic pressure that is larger than the lock position cylinder pressure (that is, the position of the annular groove 51a of the piston 51 is higher than the position of the hole 55a). The target parking brake hydraulic pressure is controlled so as to be close to the brake pad 52. As a result, the vehicle speed becomes smaller than the predetermined threshold value B, and the piston 51 moves away from the brake pad 52 and the braking force is stopped. In the process, the annular groove 51a of the piston 51 can surely pass through the position of the hole 55a after the energization of the solenoid 714 is stopped, that is, after the energization of the solenoid 714 is stopped. Influenced by the time until the piston 51 is fitted into the annular groove 51a (that is, the response time Ts of the locking member 710). It not, it is possible to realize the locked state of reliably above the piston 51 by energizing stop for the solenoid 714.

  When the lock mechanism 700 is activated as described above, when the vehicle speed becomes smaller than the predetermined threshold B as described above and the wheel cylinder pressure falls to the lock position cylinder pressure, the piston 51 is locked, and thereafter The generation state of the braking force at the time of locking corresponding to the stopping braking force is maintained.

  Thereafter, when the vehicle speed becomes zero and the vehicle stops (YES determination at step 270), the control valve is fully opened after a certain time. That is, the wheel cylinder pressure is completely reduced. In this case, since the locked state of the piston 51 is realized, the piston 51 does not move in the direction away from the brake pad 52 and the braking force does not decrease. The fixed time is appropriately determined in consideration of the response time of the locking member 710. Further, in the configuration having a sensor for detecting the position (entrance position or withdrawal position) of the locking member 710, when it is detected that the locking member 710 is in the entry position (that is, the locked state of the piston 51 is detected). The control valve may be fully open.

  FIG. 7 is a timing chart showing changes in various operation amounts and outputs corresponding to the flowchart of FIG.

  FIG. 7 (A) shows how the accelerator pedal operation amount changes, FIG. 7 (B) shows how the brake pedal operation amount changes, and FIG. 7 (C) shows how the wheel cylinder pressure changes. 7 (D) shows a change mode of the vehicle speed, FIG. 7 (E) shows a change mode of the opening degree of the control valve (the pressure increasing linear valve 410 and the pressure reducing linear valve 420), and FIG. ) Shows how the drive current (solenoid current) changes with respect to the solenoid 714, FIG. 7G shows how the piston 51 changes position (wheel cylinder displacement), and FIG. The change aspect of drive torque (target drive force) is shown.

  As shown in FIG. 7 (A), the vehicle starts and travels when the accelerator pedal is depressed from time t = t0 when the vehicle is stopped. Accordingly, as shown in FIG. 7H, the driving torque of the motor 60 is controlled based on the target braking force corresponding to the amount of depression of the accelerator pedal. Thereafter, at time t = t1, as shown in FIG. 7 (B), when the depression of the brake pedal for reaching the stop state is started, the vehicle speed decreases as shown in FIG. 7 (D). I will do it. When the depression of the brake pedal is started, the solenoid 714 is energized as shown in FIG. 7 (F), and the target braking force according to the depression amount of the brake pedal is set as shown in FIG. 7 (E). Based on this, the opening of the control valve is controlled.

  At time t = t2, when the vehicle speed falls below a predetermined threshold A as shown in FIG. 7D, the opening degree of the control valve is set with the target parking braking oil pressure as the target braking force as shown in FIG. 7E. As a result, the wheel cylinder pressure is increased to the target parking brake hydraulic pressure as shown in FIG. Accordingly, as shown in FIG. 7H, the driving torque of the motor 60 is controlled based on a target braking force for offsetting (target driving force = target braking force−target parking braking force).

  When the vehicle speed falls below the predetermined threshold B as shown in FIG. 7D at time t = t3, the energization of the solenoid 714 is stopped as shown in FIG. 7F. Then, when the vehicle speed is decreased and the wheel cylinder pressure is lowered to the lock position cylinder pressure at time t = t4, the locked state of the piston 51 is realized. Thereafter, as shown in FIG. The position 51 is locked. Therefore, thereafter, as shown in FIG. 7C, the wheel cylinder pressure decreases, but the state where the parking braking force (stop braking force) is generated is maintained. The vehicle is stopped at time t = t6, and the driver depresses the brake pedal again when the vehicle stops, so that the vehicle stops. When the amount of depression of the brake pedal increases and the target braking force corresponding to the amount of depression of the brake pedal matches the target parking braking force at time t = t8, the output by the driving torque of the motor 60 is zero. Become. The driving torque of the motor 60 may be set to zero at the time t = t6 when the stop is realized. At time t = t9 after a certain time from time t = t6, the control valve is fully opened, and the wheel cylinder pressure reaches the reservoir pressure as shown in FIG. 7C.

  FIG. 8 is a timing chart showing changes of various operation amounts and outputs corresponding to the flowchart of FIG. FIG. 8 shows how the wheel cylinder pressure is determined to be greater than or equal to the target parking brake hydraulic pressure in step 210 described above. In this case as well, when the wheel cylinder pressure drops to the lock position cylinder pressure at time t = t4 immediately before stopping, the piston 51 is locked, and thereafter, as shown in FIG. 8 (G). The position of the piston 51 is locked.

  As described above, according to the present embodiment, by operating the lock mechanism 700 immediately before stopping the vehicle, the vehicle can be stopped by the braking force generated when the lock mechanism 700 is locked. Moreover, since the locked state of the piston 51 is maintained by maintaining the energized stop state for the solenoid 714 in the stop state, the stop state can be maintained. As a result, it is possible to abolish or simplify the parking brake mechanism used for maintaining the stopped state.

  In the present embodiment, in the vehicle speed region where the vehicle speed is equal to or higher than the predetermined threshold A, the solenoid 714 is energized as described above, and the state where the locking member 710 is attracted is maintained. Therefore, even if the annular groove 51a of the piston 51 further moves beyond the position of the hole 55a by the brake operation, the locking member 710 does not fit into the annular groove 51a, and the locked state of the piston 51 is realized. Absent. As a result, in a vehicle speed region where the vehicle speed is equal to or higher than the predetermined threshold A, it is possible to generate a braking force higher than the braking force at the time of locking (stop braking force) generated in the locked state, and emergency braking requiring a high braking force. It can cope with time.

In the present embodiment, in the vehicle speed region where the vehicle speed is smaller than the predetermined threshold A, the braking / driving force adjustment control by the brake operation time control unit 530 is executed as described above. This braking / driving force adjustment control cancels the wheel cylinder pressure, which is increased more than necessary as described above, by the braking force. Therefore, from the viewpoint of energy efficiency, it is desirable that the predetermined threshold A is as small as possible. On the other hand, if the predetermined threshold A is too small, a wheel cylinder pressure larger than the lock position cylinder pressure is generated before the vehicle speed falls below the predetermined threshold B, and the piston 51 is moved closer to the brake pad 52 than the lock position. It becomes impossible to keep it moving (as a result, it becomes impossible to realize the locked state of the piston 51 unless the vehicle speed increases thereafter). From this point of view, the predetermined threshold A may be set to a lower limit value of the vehicle speed that can generate a wheel cylinder pressure larger than the lock position cylinder pressure. The predetermined threshold A is, for example, using the predetermined threshold B,
A = predetermined threshold B + pump boost time Tp × vehicle deceleration may be used. Here, the pump pressurization time Tp is an operation time of the oil pump 90 required to generate a wheel cylinder pressure larger than the vehicle braking hydraulic pressure, and changes according to the wheel cylinder pressure and the vehicle speed at that time. On the other hand, when the vehicle deceleration is large, the pump pressurization time Tp is reduced. Therefore, the maximum value under various conditions may be used as the value of (pump boost time Tp × vehicle deceleration).

  In this embodiment, the flow rate of the pressure reducing linear valve 420 is estimated based on the vehicle speed (the number of rotations of the motor 60), the opening degree of the pressure reducing linear valve 420 is controlled based on the estimation result, and the lock is performed based on the vehicle speed. Since the energization control (ON / OFF control) for the solenoid 714 of the mechanism 700 is realized, the energization control for the solenoid 714 can be realized together with the brake control based on the pump hydraulic pressure with a simple configuration in which the hydraulic sensors 432 and 430 are omitted. . However, for example, the energization control for the solenoid 714 can be performed with higher accuracy using the output value of the hydraulic sensor 430. For example, when the vehicle speed becomes smaller than the predetermined threshold A and the wheel cylinder pressure based on the output value of the hydraulic pressure sensor 430 becomes smaller than a value slightly larger than the lock position cylinder pressure, the energization to the solenoid 714 is stopped. It is good as well. Also in this case, with a simple configuration in which the hydraulic pressure sensor 432 is omitted, it is possible to realize the energization control for the solenoid 714 together with the brake control based on the pump hydraulic pressure.

  FIG. 9 is a diagram illustrating a main cross section of a hydraulic brake mechanism including a lock mechanism 700 ′ according to the second embodiment. 9 corresponds to a partial view of a portion X in FIG. 1, and a part of the configuration outside the vehicle (such as a claw portion of the brake caliper 50) is omitted in the drawing. Except for the configuration specific to the second embodiment described below, the configuration may be the same as that of the first embodiment.

  The lock mechanism 700 'according to the second embodiment is mainly different from the lock mechanism 700 according to the first embodiment in that the piston 51 is realized by two pistons 51a and 51b. That is, the lock mechanism 700 'has a double structure of the pistons 51a and 51b. A pressing spring 708 is provided between the second piston 51a and the first piston 51b. The pressing spring 708 is held by a retainer 709 provided between the second piston 51a and the first piston 51b. The retainer 709 is provided to be movable in the piston moving direction Y with respect to the second piston 51a.

  A concave groove 51a is formed on the outer peripheral surface of the first piston 51b. The space between the outer peripheral surface of the first piston 51 b and the inner peripheral surface of the wheel cylinder 55 is sealed with an annular seal 706. As a result, the first piston 51b can move (slid) along the piston moving direction Y while maintaining a liquid-tight state in the wheel cylinder 55.

  As in the first embodiment, the locking member 710 has a tip 712 that can be fitted into the annular groove 51a. The locking member 710 has a function of locking the movement of the first piston 51b. As in the first embodiment, the locking member 710 is realized by a plunger that is electromagnetically operated by a solenoid 714. The locking member 710 is provided in the radial direction of the wheel cylinder 55 and is operated to enter or leave the wheel cylinder 55 through a hole 55 a formed in the peripheral wall of the wheel cylinder 55. At the entry position, the distal end portion 712 (locking portion) of the locking member 710 is fitted into the annular groove 51a, and the locked state of the first piston 51b is formed. In the retracted position, the distal end 712 of the locking member 710 is separated from the annular groove 51a, and the unlocked state of the first piston 51b is formed.

  As shown in FIG. 9, the locking member 710 is biased toward the entry position by a spring 716. When the solenoid 714 is energized, the locking member 710 is attracted to the retracted position against the force of the spring 716, and the unlocked state of the first piston 51b as shown in FIG. 9A is formed. The When the energization of the solenoid 714 is released, the locking member 710 is biased toward the entry position by the spring 716. In this state, when the first piston 51b moves and the position of the annular groove 51a corresponds to the position of the hole 55a (position of the locking member 710) in the piston movement direction Y, the first piston 51b is biased toward the entry position. The engaging member 710 is fitted into the annular groove 51a. Thereby, the locked state of the 1st piston 51b as shown in Drawing 9 (B) is realized.

  In such a configuration, when the solenoid 714 is energized, the locking member 710 is attracted to the retracted position, so the first piston 51b moves and the position of the annular groove 51a is the position of the hole 55a. Even in a case corresponding to the above, the locked state of the first piston 51b is not realized. Further, even when the solenoid 714 is not energized (that is, even when the lock mechanism 700 is activated), unless the first piston 51b moves and the positions of the annular groove 51a and the hole 55a correspond to each other, The locked state of the first piston 51b is not realized.

  Further, when brake oil is supplied to the wheel cylinder 55 in accordance with the brake operation and the wheel cylinder pressure increases, the pressing spring 708 starts to bend. As a result, the first piston 51b moves to the right side of the page and pushes the second piston 51a to the right side of the page via the pressing spring 708. When the brake pad 52 is moved to the right side of the drawing by the second piston 51a, the brake pad 53 is moved to the left side of the drawing in response. As a result, the brake pads 52 and 53 sandwich the outer peripheral end of the brake rotor 40 and the wheel is braked.

  The lock position of the first piston 51b is set to a position where the pressing spring 708 is bent (shrinked). Therefore, the second piston 51a presses the brake pad 52 by the repulsive force of the pressing spring 708 when the first piston 51b is in the locked state, and a braking force is generated. The configuration of the pressing spring 708 (spring characteristics and length) and the locking position of the first piston 51b are the same as in Example 1 in that the braking force generated when the first piston 51b is in the locked state (braking force when locked) is the same as in the first embodiment. The braking force required for stopping or the braking force that can maintain the stopped state (= stopping braking force) is determined.

  Once the locked state of the first piston 51b is realized, the brake pads 52 and 53 are held between the outer peripheral ends of the brake rotor 40 until the locked state is released, and the braking force is generated when locked. State is maintained. This state is maintained irrespective of the hydraulic pressure in the wheel cylinder 55. That is, even when the hydraulic pressure in the wheel cylinder 55 is lowered, a state where a constant braking force is generated is maintained unless the locked state is released.

  As described above, according to the second embodiment, as in the first embodiment, the piston 51 is locked by the lock mechanism 700 even when the pump hydraulic pressure is reduced as the rotational output of the motor 60 is reduced. Thus, a stopping braking force (braking force when locked) can be generated. For example, by stopping the first piston 51b at an appropriate lock position that can generate the stopping braking force, the stopping braking force can be ensured even in a low vehicle speed region where the vehicle speed is less than Vmin. As a result, even in a low vehicle speed region where the rotational output of the motor 60 is low, it is possible to realize the stopped state and to maintain the stopped state.

  Further, in the second embodiment, the number of parts is increased as compared with the first embodiment described above by using a structure in which the piston of the wheel cylinder 55 has a double structure and the brake pad 52 is pressed via the pressing spring 708. Although the structure is complicated, the stroke amount of the first piston 51b increases as a whole, and it is possible to reduce the fluctuation of the braking force at the time of locking due to the influence of component accuracy and assembly accuracy. .

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the case where the brake device for an in-wheel motor vehicle according to the present invention is configured as a disc brake has been described, but the present invention is not limited to other hydraulic brake mechanisms such as a drum brake. Is also applicable.

  In the above-described embodiment, the solenoid 714 is used as the actuator of the lock mechanism 700, but other types of actuators may be used as long as they can be electrically controlled, including shape memory alloys and artificial muscles. May be.

  In the above-described embodiment, the state where the solenoid 714 is not energized corresponds to the operating state of the lock mechanism 700, but may be reversed. In other words, the biasing direction of the spring 716 against the locking member 710 may be reversed, and the locking member 710 may be biased toward the entry position by the suction force of the solenoid 714 when the solenoid 714 is energized.

  In the above-described embodiment, the locking braking force is set to correspond to the stopping braking force, but the present invention is not limited to this. For example, when the brake pads 52 and 53 are subjected to predetermined wear or the like, the locking braking force is set to be the stopping braking hydraulic pressure + α so that the vehicle can be stopped or maintained by the locking braking force. May be.

  In the above-described embodiment, the pressure increasing linear valve 410 and the pressure reducing linear valve 420 are used as the hydraulic control means for controlling the hydraulic pressure introduced into the wheel cylinder 55. However, when control such as ABS is not required. The hydraulic control means may be configured by only one of the pressure-increasing linear valve 410 and the pressure-decreasing linear valve 420.

  Further, the lock mechanism 700 according to the first embodiment and the second embodiment can be applied to a configuration in which the wheel cylinder pressure is controlled by using the master cylinder pressure in addition to the pump hydraulic pressure, for example, as shown in FIG. .

  FIG. 10 is a diagram showing a main circuit of a brake device for an in-wheel motor vehicle that uses a master cylinder pressure. A brake pedal 920 is connected to the master cylinder 900. The master cylinder 900 has a hydraulic chamber 905 inside. In the hydraulic chamber 905, a master cylinder pressure corresponding to the brake depression force is generated. The master cylinder 900 may be disposed on the front side of the brake pedal 920 (on the front side of the brake booster), as in a normal vehicle (a vehicle that is not an in-wheel motor vehicle). A master passage 915 is connected to the hydraulic chamber 905. The master passage 915 is connected to the wheel cylinder 55 via a master cut valve 910. At this time, the master passage 915 is connected to a position between the oil pump 90 and the pressure-increasing linear valve 410 in the oil passage 300. The master cut valve 910 is a normally open valve that is normally open. The master cut valve 910 may be disposed in the wheel, like the pressure-increasing linear valve 410 and the pressure-decreasing linear valve 420, or may be disposed in an engine room or the like as in a normal vehicle. For example, the master cut valve 910 may be set only for a predetermined one of all wheels (typically four wheels) of the vehicle, or for a predetermined two wheels or three or more wheels. May be set independently of each other. When set for each of two predetermined wheels, two hydraulic chambers of the master cylinder are set, and each hydraulic chamber is communicated with the wheel cylinder of the corresponding wheel via a similar master cut valve. Just do it. A stroke simulator 930 may also be connected to the master passage 915 via a simulator cut valve 940. The simulator cut valve 940 is a normally closed electromagnetic on-off valve that normally shuts off the master passage 915 and the stroke simulator 930 and is turned on when supplied with an ON signal from the control device 500. The stroke simulator 930 is configured to allow an amount of brake oil corresponding to the master cylinder pressure generated in the hydraulic pressure chamber 905 of the master cylinder 900 to flow into the interior of the master cylinder 900 under the condition that the simulator cut valve 940 is opened. Yes. The simulator cut valve 940 is opened when the master cut valve 910 is closed. As a result, an amount of brake oil corresponding to the master cylinder pressure flows into the stroke simulator 930 from the hydraulic chamber 905. Accordingly, a pedal stroke corresponding to the brake depression force is generated in a state where the master cut valve 910 is closed. When the master cut valve 910 is in the open state, the pump hydraulic pressure generated by the oil pump 90 and the master cylinder pressure generated by the master cylinder 900 can be supplied to the wheel cylinder 55. In this state, it is possible to control the wheel cylinder pressure using the pump hydraulic pressure generated by the oil pump 90 and the master cylinder pressure generated by the master cylinder 900. This master cylinder pressure may be used at the time of a failure, or may be used when the vehicle speed decreases.

It is sectional drawing which shows the principal part of the wheel to which Example 1 of the brake device for in-wheel motor vehicles by this invention was applied. It is a figure which shows the main circuits of the brake device for in-wheel motor vehicles by Example 1. FIG. It is a functional block diagram of the control apparatus 500 with respect to the brake device for in-wheel motor vehicles by Example 1. FIG. It is a figure which shows the main cross section of a hydraulic brake mechanism provided with the lock mechanism 700 by a present Example. It is a figure which shows the braking force replenishment / maintenance function implement | achieved by the lock mechanism 700 of a present Example. It is a flowchart which shows one Example of the main process implement | achieved by the control apparatus 500 by a present Example in the process from a stop state to the next stop state. FIG. 7 is a timing chart showing various signal waveforms or output waveforms corresponding to the flowchart of FIG. 6 (No. 1). 7 is a timing chart showing various signal waveforms or output waveforms corresponding to the flowchart of FIG. 6 (part 2). It is a figure which shows the main cross section of a hydraulic brake mechanism provided with the locking mechanism 700 'by Example 2. FIG. It is a figure which shows the main circuits of the brake device for in-wheel motor vehicles by other Examples.

Explanation of symbols

40 brake rotor 50 brake caliper 51 piston 51a annular groove 55 wheel cylinder 55a hole 52, 53 brake pad 60 motor 61 stator core 62 stator coil 63 rotor 80 planetary gear 81 sun gear shaft 82 sun gear 83 pinion gear 84 planetary carrier 85 ring gear 86 pin 90 Oil pump 110 Shaft 111, 120, 121 Oil passage 112 Oil hole 130 Oil reservoir 140, 150 Ball joint 170 Upper arm 180 Lower arm 190 Spring 300 Oil passage 400 Cooling cut valve 410 Pressure increasing linear valve 420 Pressure reducing linear valve 500 Control device 510 Brake Operation determination unit 530 Brake operation control unit 600 Brake operation amount detection means 610 Wheel speed sensor 6 0 accelerator opening sensor 700 locking mechanism 706 seals 708 compression spring 710 engaging member 712 distal end (locking portion)
714 Solenoid 716 Spring

Claims (8)

In a brake device for an in-wheel motor vehicle equipped with a motor for rotating the wheel in the wheel,
A hydraulic pump connected to the output shaft of the motor and operated by the rotational output of the motor;
A friction member that acts on the wheel, a hydraulic cylinder that communicates with the hydraulic pump, and a piston that is provided in the hydraulic cylinder and that presses the friction member against the wheel by the action of hydraulic pressure guided into the hydraulic cylinder; A hydraulic brake mechanism that applies a braking force to a wheel by a pressing force of a piston against the friction member;
Hydraulic control means for controlling the hydraulic pressure introduced into the hydraulic cylinder;
A brake device comprising: a lock mechanism that is provided to the hydraulic brake mechanism and locks the piston while pressing the friction member. The locking mechanism is
A groove formed in the outer peripheral surface of the piston,
It has a locking part that fits into the groove part and locks the piston, and is operated to enter or exit from the hydraulic cylinder through a hole formed in the peripheral wall of the hydraulic cylinder, A locking member in which the locking portion is fitted into the groove portion at the entry position to form a locked state of the piston, and the locking portion is separated from the groove portion at the retracted position to form an unlocked state of the piston. Including
In the operating state of the locking mechanism, a state is formed in which the locking member is biased toward the entry position, and when the piston reaches the lock position, the locking portion is fitted into the groove portion. The brake device according to claim 1, wherein the locked state is realized. The hydraulic brake mechanism further includes a second piston using the piston as a first piston,
The second piston is movable in the same direction as the first piston, and is connected to the first piston via an elastic body that can contract along the moving direction,
3. The brake device according to claim 1, wherein when the first piston is in a locked position, the second piston presses the friction member by an action of a repulsive force of the elastic body.   The brake device according to any one of claims 1 to 3, wherein the lock mechanism is activated at a stage before the vehicle stops.   The brake device according to any one of claims 1 to 4, wherein the lock mechanism is maintained in an operating state when the vehicle is stopped.   The brake device according to any one of claims 1 to 5, wherein an operating state of the lock mechanism is released when the vehicle starts.   The brake device according to any one of claims 1 to 6, wherein a lock position of the piston is set before a maximum movement position in a movement stroke of the piston.   The brake device according to any one of claims 1 to 7, wherein the lock mechanism is inhibited from operating when a vehicle speed is equal to or higher than a predetermined value and an operation of a brake pedal is detected.

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