JP4677925B2 - Brake device for in-wheel motor vehicles - Google Patents

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.

  2. Description of the Related Art Conventionally, an in-wheel motor in which a brake oil pressure source is provided outside a wheel is known (see, for example, Patent Document 1).

In addition, in the vehicle braking device including a braking energy regeneration unit equipped for each wheel, a storage device that stores braking energy generated by the braking energy regeneration unit, and a control device that controls the braking energy regeneration unit, The braking energy regeneration unit has a hydraulic pump motor connected to the wheel shaft and driven by the rotational force of the wheel, and an accumulator as the accumulator that stores the hydraulic pressure generated by the hydraulic pump motor, and accumulates in the accumulator A vehicular braking device is known that uses the braking energy thus produced as a driving force when starting the vehicle (see, for example, Patent Document 2).
JP 2005-81872 A JP-A-11-157422

  By the way, as described in the above-mentioned Patent Document 1, in the in-wheel motor, the space in the wheel is largely occupied by the wheel driving motor, so that the brake oil pressure source is disposed outside the wheel. It is common to use a pump system (motor, pump, accumulator).

  However, in-wheel motors are also useful in terms of space efficiency and cost if a brake oil pressure source can be efficiently arranged in the wheel.

  Therefore, an object of the present invention is to provide a brake device for an in-wheel motor vehicle in which a brake oil pressure source is efficiently arranged in the wheel.

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 hydraulic brake mechanism which generates a wheel braking force by the oil pressures,
A hydraulic circuit for guiding the hydraulic pressure generated by the hydraulic pump to the hydraulic brake mechanism;
Clutch means provided between the output shaft of the motor and the input shaft of the hydraulic pump and capable of opening and closing;
And a rotary inertia body provided on an input shaft of the hydraulic pump .

A second invention is a brake device for an in-wheel motor vehicle provided 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 hydraulic brake mechanism that generates braking force of the wheel by hydraulic pressure;
A hydraulic circuit for guiding the hydraulic pressure generated by the hydraulic pump to the hydraulic brake mechanism;
A second brake device that applies a braking force different from the hydraulic braking force generated by the hydraulic pump to the wheels;
When the hydraulic pressure generated by the hydraulic pump becomes a predetermined value or less, the braking force by the second brake device is applied to the wheels.

3rd invention is the brake device which concerns on 2nd invention,
The second brake device includes:
A master cylinder that generates hydraulic pressure according to the amount of operation of the brake pedal;
And a second hydraulic circuit that guides the hydraulic pressure generated by the master cylinder to the hydraulic brake mechanism via a valve that can be controlled to open and close . Thereby, even when the hydraulic pressure generated by the hydraulic pump becomes equal to or less than a predetermined value, the necessary braking force can be secured using the master cylinder pressure.

4th invention is the brake device which concerns on 2nd invention,
The second brake device is an electric brake device . Thereby, even when the hydraulic pressure generated by the hydraulic pump is equal to or less than a predetermined value, the necessary braking force can be ensured by using the braking force generated by the electric brake device.

5th invention is the brake device which concerns on invention in any one of 1-4 ,
It is characterized by having a hydraulic pressure estimation means for estimating the magnitude of the hydraulic pressure generated by the hydraulic pump based on the rotational speed of the motor . As a result, it is possible to eliminate a hydraulic pressure sensor that detects the magnitude of the hydraulic pressure generated by the hydraulic pump.

  ADVANTAGE OF THE INVENTION According to this invention, the brake device for in-wheel motor vehicles by which the pressure source of brake oil is efficiently arrange | positioned in a wheel is 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.

  Planetary gear 80 constitutes a speed reduction mechanism for rotation of 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 brake 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.

  When the brake oil is supplied to the wheel cylinder 55, the brake 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 brake 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. Thereby, it becomes possible to generate the braking force of the wheels by 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 generate the braking force of 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. . For this purpose, the oil pump 90 is designed for oil performance such as capacity and output in consideration of the braking ability required for the hydraulic brake mechanism.

  In this embodiment, the hydraulic pressure generating source (oil pump 90) is disposed in the wheel together with the hydraulic brake mechanism, so that the pump is provided outside the wheel (typically on the front side of the brake booster). Since the oil passage from the oil pressure generation source to the wheel cylinder 55 can be shortened, the pipe vibration is reduced and the response of the brake is improved.

  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 a quantity detection means 600 and a wheel speed sensor 610 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. In the case of a configuration having a master cylinder, the brake operation determination unit 510 may detect the operation of the brake pedal based on a master pressure sensor or the like that detects the master cylinder pressure.

  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. Further, in the present 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 hydraulic circuit that connects the master cylinder and the wheel cylinder 55 of the specific wheel is provided. It is possible to eliminate the master cylinder itself or to simplify the entire configuration of the hydraulic brake mechanism.

  FIG. 4 is a diagram illustrating a main circuit of a brake device for an in-wheel motor vehicle according to the second embodiment. In the second embodiment, a hydraulic circuit from the master cylinder 700 is added to the first embodiment. Hereinafter, the same configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  A brake pedal 720 is connected to the master cylinder 700. The master cylinder 700 includes a hydraulic chamber 705 therein. In the hydraulic pressure chamber 705, a master cylinder pressure corresponding to the brake depression force is generated. The master cylinder 700 may be disposed adjacent to the brake pedal 720 as in a normal vehicle (a vehicle that is not an in-wheel motor vehicle).

  A master passage 715 is connected to the hydraulic chamber 705. The master passage 715 is connected to the wheel cylinder 55 via a master cut valve 710. At this time, the master passage 715 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 710 is a normally open valve that is normally open.

  The master cut valve 710 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 710 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 730 may also be connected to the master passage 715 via a simulator cut valve 740. The simulator cut valve 740 is a normally closed electromagnetic on-off valve that normally shuts off the master passage 715 and the stroke simulator 730 and supplies them with an ON signal from the control device 500. The stroke simulator 730 is configured to cause the brake oil of an amount corresponding to the master cylinder pressure generated in the hydraulic pressure chamber 705 of the master cylinder 700 to flow into the interior of the master cylinder 700 under the situation where the simulator cut valve 740 is opened. Yes.

  The simulator cut valve 740 is opened when the master cut valve 710 is closed. As a result, an amount of brake oil corresponding to the master cylinder pressure flows from the hydraulic chamber 705 into the stroke simulator 730. Accordingly, a pedal stroke corresponding to the brake depression force is generated in a state where the master cut valve 710 is closed.

  When the master cut valve 710 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 700 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 700.

  FIG. 5A is a diagram showing the relationship between the pump hydraulic pressure generated by the oil pump 90 and the vehicle speed (V). As shown in FIG. 5A, 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.

  In contrast, in the present embodiment, the wheel cylinder pressure is controlled using the master cylinder pressure generated by the master cylinder 700 in addition to the pump hydraulic pressure generated by the oil pump 90. Even when the pump hydraulic pressure decreases with the decrease, a desired braking force can be generated using the master cylinder pressure. For example, as shown in FIG. 5B, in a low vehicle speed region where the vehicle speed is less than a predetermined value Vmin, the braking force necessary for stopping the vehicle can be obtained by compensating the insufficient pump hydraulic pressure with the master cylinder pressure. it can.

  FIG. 6 is a functional block diagram of the control device 500 according to the present embodiment. As shown in FIG. 6, the control device 500 includes a brake operation determination unit 510 and a brake operation time control unit 530. In addition to the hydraulic pressure sensors 430 and 432, a wheel speed sensor 610 is connected to the brake operation time control unit 530. In addition to the cooling cut valve 400, the pressure increasing linear valve 410, and the pressure reducing linear valve 420, a master cut valve 710 is connected to the brake operation control unit 530 as a control target.

  FIG. 7 is a functional block diagram of the brake operation time control unit 530 according to this embodiment. As shown in FIG. 7, the brake operation control unit 530 includes an auxiliary hydraulic pressure necessity determination unit 532, a normal brake control unit 534, an auxiliary brake control unit 536, and a valve control unit 538. The processing of these units will be described with reference to FIG.

  FIG. 8 is a flowchart showing a flow of main processing realized by the control device 500 according to the present embodiment in the brake operation process up to stopping.

  In step 100, it is determined by the brake operation determination unit 510 whether or not the brake operation has been started. When the brake operation determination unit 510 determines that the brake operation has been started, the process proceeds to step 110.

  In step 110, the cooling cut valve 400 is closed by the valve control unit 538. 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 120, the auxiliary hydraulic pressure necessity determination unit 532 determines whether the vehicle speed is equal to or higher than a predetermined value Vmin based on the output signal of the wheel speed sensor 610. If the vehicle speed is equal to or higher than the predetermined value Vmin, the process proceeds to step 130. If the vehicle speed is less than the predetermined value Vmin, the process proceeds to step 140.

  In step 130, normal brake control using pump hydraulic pressure is executed by the normal brake control unit 534. Specifically, the normal brake control unit 534 controls the open / close state of the pressure-increasing linear valve 410 and the pressure-reducing linear valve 420 via the valve control unit 538 to generate a braking force according to the operation amount of the brake pedal. . For example, the normal brake control unit 534 calculates the target braking force according to the operation amount of the brake pedal, determines the target opening of the pressure increasing linear valve 410 and the pressure reducing linear valve 420 according to the target braking force, An instruction is output to the valve control unit 538 so that the target opening degree is realized. The normal brake control by the normal brake control unit 534 is continued until the vehicle speed becomes less than the predetermined value Vmin by the normal brake control.

  In step 140, the master cut valve 710 is opened by the valve control unit 538. When the master cut valve 710 is opened, the master cylinder pressure can be supplied to the wheel cylinder 55 via the pressure-increasing linear valve 410.

  In step 150, the auxiliary brake control unit 536 executes auxiliary brake control using the pump hydraulic pressure and the master cylinder pressure. Specifically, the auxiliary brake control unit 536 controls the open / close state of the pressure-increasing linear valve 410 and the pressure-reducing linear valve 420 via the valve control unit 538 to generate a braking force according to the operation amount of the brake pedal. . For example, the auxiliary brake control unit 536 calculates a braking force necessary for stopping, determines the target opening of the pressure increasing linear valve 410 and the pressure reducing linear valve 420 according to the braking force, and the target opening is realized. Thus, an instruction is output to the valve control unit 538. At this time, as shown in FIG. 5B, the master cylinder pressure may be introduced into the wheel cylinder 55 in such a manner that the master cylinder pressure increases as the vehicle speed decreases. The auxiliary brake control by the auxiliary brake control unit 536 is continued until the vehicle speed becomes zero by the auxiliary brake control (that is, continued until the vehicle is determined to be stopped in step 160).

  As described above, according to the present embodiment, the master cylinder pressure is introduced into the wheel cylinder 55 in the low vehicle speed region where the pump hydraulic pressure is insufficient. Therefore, the shortage of the pump hydraulic pressure is compensated by the master cylinder pressure and is necessary for stopping the vehicle. A braking force can be secured.

  Further, according to the present embodiment, it is possible to eliminate the hydraulic pressure sensor 432 because the pump hydraulic pressure shortage state is estimated based on the vehicle speed and the normal brake control and the auxiliary brake control are switched. Similarly, switching from normal brake control to auxiliary brake control may be realized when the rotation speed (or rotation speed, hereinafter the same) of the motor 60 or the oil pump 90 falls below a predetermined value. In this case as well, the hydraulic pressure sensor 432 can be eliminated. However, even in these cases, the hydraulic sensor 432 can be provided without being abolished, and the output signal of the hydraulic sensor 432 can be used for other purposes (for example, abnormality detection).

  The third embodiment is different from the second embodiment in that the shortage of the pump hydraulic pressure is compensated not by the master cylinder pressure but by the braking force by the electric parking brake (EPB). Hereinafter, the configuration unique to the third embodiment will be described, but other configurations may be the same as those of the second embodiment.

  FIG. 9 is a diagram showing a main circuit of the brake device for the in-wheel motor vehicle of the present embodiment. The electric parking brake 800 includes a PKB actuator 810 (for example, an electric motor). Under the control of the control device 500, the PKB actuator 810 drives the parking brake mechanism (not shown) provided on the wheel by driving the cable up or down. When the cable is wound up or rewound by the PKB actuator 810, the parking brake mechanism realizes the application or release of the braking force to the wheels by the tension transmitted through the cable. The parking brake mechanism does not need to be a cable type, and may be of another type (for example, a parking brake mechanism with a built-in wheel using a ball screw).

  FIG. 10 is a functional block diagram of the brake operation control unit 530 in the control device 500 according to the present embodiment. As shown in FIG. 10, the brake operation time control unit 530 includes an auxiliary hydraulic pressure necessity determination unit 532, a normal brake control unit 534, an auxiliary brake control unit 536, and a valve control unit 538. An electric parking brake 800 is connected to the auxiliary brake control unit 536.

  FIG. 11 is a flowchart showing a flow of main processes realized by the control device 500 according to the present embodiment in the brake operation process until the vehicle stops. The processing of steps 200 to 230 may be the same as the processing of steps 100 to 130 described with reference to FIG.

  If the vehicle speed is less than the predetermined value Vmin, the routine proceeds to step 240. In step 240, electric parking brake 800 is operated in accordance with an instruction from auxiliary brake control unit 536. For example, the auxiliary brake control unit 536 calculates a braking force necessary for stopping, and outputs an instruction to the electric parking brake 800 so that the braking force is generated. At this time, the braking force generated by the electric parking brake 800 may be changed in a manner that increases as the vehicle speed decreases, as shown in FIG. 5B, similarly to the master cylinder pressure in the second embodiment. Or it may be fixed.

  The auxiliary brake control by the auxiliary brake control unit 536 is continued until the vehicle speed becomes zero by the auxiliary brake control (that is, continued until stop is determined in step 250).

  Thus, according to the present embodiment, since the electric parking brake 800 is operated in the low vehicle speed region where the pump hydraulic pressure is insufficient, the shortage of the pump hydraulic pressure is compensated by the braking force generated by the electric parking brake 800, and the vehicle The braking force required for stopping can be ensured.

  Further, according to the present embodiment, it is possible to eliminate the hydraulic pressure sensor 432 because the pump hydraulic pressure shortage state is estimated based on the vehicle speed and the normal brake control and the auxiliary brake control are switched. Similarly, switching from normal brake control to auxiliary brake control may be realized when the rotation speed of the motor 60 or the oil pump 90 falls below a predetermined value. In this case as well, the hydraulic pressure sensor 432 can be eliminated.

  FIG. 12 is a cross-sectional view schematically illustrating a main part of a wheel including a brake device for an in-wheel motor vehicle according to a fourth embodiment. The brake device according to this embodiment is different from the configuration shown in FIG. 1 (configuration according to the first embodiment) mainly in that it includes a clutch 900 and a flywheel 910. Hereinafter, the configuration unique to the fourth embodiment will be described, but other configurations may be the same as those of the first embodiment.

  The clutch 900 is provided between the output shaft of the motor 60 and the input shaft of the oil pump 90, and has a function of switching the connection state between the motor 60 and the oil pump 90 to engagement or release. In the example shown in FIG. 12, the vehicle inner end portion of the shaft 110 (output shaft of the motor 60) spline-connected to the planetary carrier 84 extends further to the vehicle inner side beyond the planetary carrier 84. An input shaft of the oil pump 90 is connected to an extension portion of the shaft 110 via a clutch 900. The input shaft of the oil pump 90 extends coaxially with the shaft 110 and is provided with a flywheel 910 that forms a rotary inertia body. The clutch 900 may be, for example, a one-way clutch that transmits only rotation in one direction of the motor 60 (for example, rotation in the vehicle forward direction), or may be a clutch that can transmit rotation in the forward and reverse directions. The switching of the state (engaged or released) of the clutch 900 may be realized by an actuator for clutch control.

  When the clutch 900 between the motor 60 and the oil pump 90 is engaged, the oil pump 90 is operated by the rotational output of the motor 60 as described above.

  On the other hand, when the clutch 900 between the motor 60 and the oil pump 90 is released, transmission of the rotational output of the motor 60 to the input shaft of the oil pump 90 is interrupted. In this case, when the clutch 900 is released when the rotational speed of the motor 60 is not zero, the input shaft of the oil pump 90 continues to rotate due to the rotational inertia of the flywheel 910 at that time.

  By the way, in the state where the clutch 900 between the motor 60 and the oil pump 90 is engaged, as described above, in the low vehicle speed region where the rotational output of the motor 60 becomes low, the rotational output of the motor 60 decreases. There is a possibility that the pump hydraulic pressure (or the amount of oil that can be sucked) that can be generated is insufficient, and the necessary braking force cannot be obtained only with the pump hydraulic pressure.

  Therefore, in this embodiment, the clutch 900 between the motor 60 and the oil pump 90 is released before reaching the low vehicle speed region where the rotational output of the motor 60 is low. Thereby, even in the low vehicle speed region, the input shaft of the oil pump 90 continues to rotate due to the rotational inertia of the flywheel 910, so that the pump hydraulic pressure in the low vehicle speed region is prevented from decreasing.

  FIG. 13 is a functional block diagram of the brake operation control unit 530 in the control device 500 according to the present embodiment. As shown in FIG. 13, the brake operation time control unit 530 includes an auxiliary hydraulic pressure necessity determination unit 532, a normal brake control unit 534, an auxiliary brake control unit 536, and a valve control unit 538. The auxiliary brake control unit 536 performs hydraulic control related to the clutch 900.

  FIG. 14 is a flowchart showing a flow of main processing realized by the control device 500 according to the present embodiment in the brake operation process up to stopping. The processing in steps 300 and 310 may be the same as the processing up to steps 100 and 110 described with reference to FIG.

  In step 320, the auxiliary hydraulic pressure necessity determination unit 532 determines whether or not the vehicle speed is equal to or higher than a predetermined value V0 based on the output signal of the wheel speed sensor 610. If the vehicle speed is greater than or equal to the predetermined value V0, the process proceeds to step 330. If the vehicle speed is less than the predetermined value V0, the process proceeds to step 340. The predetermined value V0 is determined in consideration of braking energy or the like as necessary to make the vehicle speed of the predetermined value V0 zero, and may be a value larger than the predetermined value Vmin. This is because the rotational speed of the input shaft of the oil pump 90 gradually decreases due to the rotational inertia of the flywheel 910.

  In step 330, normal brake control using pump hydraulic pressure is executed by the normal brake control unit 534. The normal brake control by the normal brake control unit 534 is continued until the vehicle speed becomes less than the predetermined value V0 by the normal brake control.

  In step 340, the clutch 900 is released by the auxiliary brake control unit 536. When the clutch 900 is released, the input shaft of the oil pump 90 is disconnected from the shaft 110 of the motor 60 and is rotated by the rotational inertia of the flywheel 910 without being affected by the decrease in the rotational speed of the shaft 110 due to the braking force. to continue. That is, the rotational speed of the oil pump 90 is independent of the rotational speed of the shaft 110 that decreases by the subsequent braking, and is therefore greater than the rotational speed of the shaft 110.

  In step 350, auxiliary brake control using pump hydraulic pressure is executed by the auxiliary brake control unit 536. Specifically, the auxiliary brake control unit 536 controls the open / close state of the pressure-increasing linear valve 410 and the pressure-reducing linear valve 420 via the valve control unit 538 to generate a braking force according to the operation amount of the brake pedal. . As a result, the rotational energy of the flywheel 910 when the vehicle speed is about V0 is used as a pump hydraulic pressure source (braking force source). The auxiliary brake control by the auxiliary brake control unit 536 is continued until the vehicle speed becomes zero by the auxiliary brake control (that is, continued until the vehicle is determined to be stopped in step 360).

  As described above, according to the present embodiment, in the low vehicle speed region where the pump hydraulic pressure can be insufficient, the rotational inertia of the flywheel 910 is used to prevent the pump hydraulic pressure from being insufficient and to secure the braking force necessary for stopping the vehicle. can do.

  Further, according to the present embodiment, it is possible to eliminate the hydraulic pressure sensor 432 because the pump hydraulic pressure shortage state is estimated based on the vehicle speed and the normal brake control and the auxiliary brake control are switched. Similarly, switching from normal brake control to auxiliary brake control may be realized when the rotation speed of the motor 60 or the oil pump 90 falls below a predetermined value. In this case as well, the hydraulic pressure sensor 432 can be eliminated.

  In this embodiment, the clutch 900 released as described above is used when the rotational speed of the shaft 110 of the motor 60 increases and catches up with the rotational speed of the oil pump 90 at the time of subsequent start or reacceleration. , Switched to the engaged state. As a result, a smooth engagement of the clutch 900 with high efficiency and low shock is realized.

  FIG. 15 is a diagram illustrating a main circuit of a brake device for an in-wheel motor vehicle according to the fifth embodiment. The brake device according to the present embodiment is different from the configuration shown in FIG. 1 (configuration according to the first embodiment) mainly in that the pressure increasing linear valve 410 and the hydraulic pressure sensors 432 and 430 are omitted. Hereinafter, the configuration unique to the fourth embodiment will be described, but other configurations may be the same as those of the first embodiment.

  The pressure reducing linear valve 420 connects the wheel cylinder 55 and the oil reservoir 130. The pressure-reducing linear valve 420 is a linear control valve that, when supplied with a drive signal from the control device 500, increases the opening according to the magnitude of the drive signal. Therefore, the wheel cylinder pressure can be linearly controlled based on the drive current supplied to the pressure reducing linear valve 420. The controller 500 receives the rotation speed of the motor 60 (or the oil pump 90) (output of the rotation speed sensor). The control device 500 determines a drive current to be supplied to the pressure reducing linear valve 420 based on the rotation speed of the motor 60.

  FIG. 16 is a flowchart illustrating the flow of a drive current value determination process realized by the control device 500 according to the fifth embodiment.

  In step 400, the rotational speed of the motor 60 is measured based on the output of the rotational speed sensor.

  In step 410, based on the measured rotation speed of the motor 60, the flow rate of the pressure reducing linear valve 420 corresponding to the rotation speed is estimated (calculated).

  In step 420, a target value of braking force (target braking force) is captured. The target braking force is calculated by another control device (for example, a brake ECU) and is taken into the control device 500. However, as in the above-described embodiment, the control device 500 itself may calculate according to the brake operation amount obtained from the brake operation amount detection means 600.

  In step 430, the target value of hydraulic pressure is calculated based on the acquired target braking force.

  In step 440, the target valve opening of the pressure reducing linear valve 420 is calculated based on the calculated target value of the hydraulic pressure and the estimated flow rate of the pressure reducing linear valve 420. In other words, the valve opening degree at which the hydraulic pressure target value is realized by the oil supplied at the estimated flow rate of the pressure reducing linear valve 420 is calculated as the target valve opening degree.

  In step 450, 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 pressure reducing linear valve 420. When the drive signal is supplied from the control device 500, the opening degree is realized in the pressure-reducing linear valve 420 according to the magnitude of the drive signal.

  As described above, according to the present embodiment, an optimum braking force based on the pump hydraulic pressure can be generated with a simple configuration using only one linear control valve for one wheel. Further, since the flow rate of the pressure reducing linear valve 420 is estimated based on the number of rotations of the motor 60 and the opening degree of the pressure reducing linear valve 420 is controlled based on the estimation result, the hydraulic sensors 432 and 430 are omitted in a simple configuration. An optimal braking force based on the pump hydraulic pressure can be generated.

  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, the second embodiment and the third embodiment described above can be realized in combination. In this case, the auxiliary braking force by the master cylinder pressure and the auxiliary braking force by the electric parking brake 800 may be selectively used or may be used in cooperation.

  Further, in the above-described second embodiment, a control mode is realized in which the wheel cylinder 55 is controlled with the pump hydraulic pressure as the main and the master cylinder pressure as the sub, and the shortage of the pump hydraulic pressure occurring in the low vehicle speed range is compensated with the master cylinder pressure. However, the pump hydraulic pressure and the master cylinder pressure may be appropriately distributed and introduced into the wheel cylinder 55 by other control modes.

  Further, in the above-described second embodiment, the pump hydraulic pressure shortage state is estimated based on the vehicle speed so that the hydraulic pressure sensor 432 can be omitted, but the pump hydraulic pressure is determined based on the output signal of the hydraulic pressure sensor 432. When the value falls below the value, switching from the normal brake control to the auxiliary brake control may be realized.

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 circuits of the brake device for in-wheel motor vehicles by Example 2. FIG. FIG. 5A is a diagram showing the correlation between the pump hydraulic pressure and the vehicle speed, and FIG. 5B shows an example of a control mode in which the master cylinder pressure compensates for the shortage of the pump hydraulic pressure that occurs in the low vehicle speed range. 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 2. FIG. 6 is a functional block diagram of a brake operation control unit 530 according to Embodiment 2. FIG. It is a flowchart which shows the flow of the main processing implement | achieved by the control apparatus 500 by Example 2 in the brake operation process leading to a stop. It is a figure which shows the main circuits of the brake device for in-wheel motor vehicles of Example 3. FIG. FIG. 10 is a functional block diagram of a brake operation control unit 530 according to a third embodiment. It is a flowchart which shows the flow of the main processing implement | achieved by the control apparatus 500 by Example 3 in the brake operation process leading to a stop. It is sectional drawing which shows roughly the principal part of a wheel provided with the brake device for in-wheel motor vehicles by Example 4. FIG. It is a functional block diagram of the control part 530 at the time of brake operation in the control apparatus 500 by Example 4. It is a flowchart which shows the flow of the main processing implement | achieved by the control apparatus 500 by Example 4 in the brake operation process leading to a stop. It is a figure which shows the main circuit of the brake device for in-wheel motor vehicles by Example 5. FIG. 10 is a flowchart illustrating a flow of a drive current value determination process realized by a control device 500 according to a fifth embodiment.

Explanation of symbols

40 Brake rotor 50 Brake caliper 55 Wheel cylinder 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 determining unit 530 When brake is operated Control unit 600 Brake operation amount detection means 610 Wheel speed sensor

Claims (6)

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 hydraulic brake mechanism which generates a wheel braking force by the oil pressure,
A hydraulic circuit for guiding the hydraulic pressure generated by the hydraulic pump to the hydraulic brake mechanism;
Clutch means capable of opening / closing control provided between the output shaft of the motor and the input shaft of the hydraulic pump;
A brake device comprising: a rotary inertia body provided on an input shaft of a hydraulic pump . 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 hydraulic brake mechanism that generates braking force of the wheel by hydraulic pressure;
A hydraulic circuit for guiding the hydraulic pressure generated by the hydraulic pump to the hydraulic brake mechanism;
A second brake device that applies a braking force different from the hydraulic braking force generated by the hydraulic pump to the wheels;
The brake device according to claim 1 , wherein when the hydraulic pressure generated by the hydraulic pump becomes equal to or less than a predetermined value, a braking force by the second brake device is applied to a wheel. The second brake device includes:
A master cylinder that generates hydraulic pressure according to the amount of operation of the brake pedal;
The brake device according to claim 2 , further comprising: a second hydraulic circuit that guides the hydraulic pressure generated by the master cylinder to the hydraulic brake mechanism via a valve that can be controlled to be opened and closed. The second brake device is an electric brake device, the brake device according to claim 2. The brake device according to any one of claims 1 to 4 , further comprising: a hydraulic pressure estimation unit that estimates a hydraulic pressure generated by the hydraulic pump based on a rotation speed of the motor. The brake device according to any one of claims 1 to 5, further comprising an oil circulation mechanism that circulates oil in the motor using hydraulic pressure generated by the hydraulic pump.

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