JP2011098734A - Brake liquid pressure control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain sound vibration caused by vibration generated from a motor when operating a pump, in a brake liquid pressure control device. <P>SOLUTION: This brake liquid pressure control device includes two sets of independently drivable rotational driving type pump motors installed in a housing so that rotary shafts mutually become the same direction, two sets of pumps arranged in the housing and driven by the respective pump motors, and a control unit installed in the housing and capable of rotatingly driving the respective pump motors for pressurizing a plurality of wheel cylinders arranged in a vehicle by pressurizing a brake liquid. The control unit rotatingly drives the respective pump motors based on a command value arithmetically operated in response to brake operation of a driver, and mutually reversely rotates the respective motors when request liquid pressure to the wheel cylinders is higher than preset liquid pressure, and pressurizes the wheel cylinders by rotating one of the rotational driving type pump motors when the request liquid pressure is lower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake fluid pressure control device, and more particularly to a brake fluid pressure control device including a motor pump for each wheel and a hydraulic unit capable of performing anti-skid brake control independently for each wheel.

  In the conventional brake fluid pressure control device, each wheel is provided with a hydraulic unit independently, and each hydraulic unit and the master cylinder are connected by a steel pipe.

JP-A-5-147524

In the technique described in Patent Document 1, the above-described brake fluid pressure control device has the following problems. Since each wheel is independently provided with a hydraulic unit composed of a motor pump, and the motor rotates in the same direction when the motor pump is operated, the number of hydraulic units increases, leading to an increase in cost. Further, there is a problem that vibrations generated from the motor when the pump is operated are superimposed on each other and transmitted to the inside of the vehicle via the steel pipe.
The present invention has been made paying attention to the above problem, and an object of the present invention is to suppress sound vibration caused by vibration generated from a motor during operation of a pump in a brake fluid pressure control device.

  In order to achieve the above object, in the present invention, two sets of rotary drive pump motors that are assembled to the housing so that the rotation axes thereof are in the same direction and can be driven independently are provided in the housing. Two sets of pumps driven by a pump motor, and a control unit which is assembled to the housing and capable of rotating the pump motors to pressurize brake fluid and pressurize a plurality of wheel cylinders provided in the vehicle And when the control unit rotates and drives each pump motor based on a command value calculated in accordance with a driver's brake operation, and the required hydraulic pressure for the wheel cylinder is higher than a set hydraulic pressure. The motors are rotated in reverse from each other. If the motor is low, one of the rotary drive pump motors is rotated to rotate the motor. Was that pressurizing the cylinder.

  Therefore, the vibrations generated by the motors with different rotation directions are canceled out by the vibrations generated by the motors of each other, and the sound vibration caused by the vibrations generated from the motors during the pump operation can be suppressed.

It is the perspective view which looked at the brake fluid pressure control unit in a present Example from the pump motor side. 1 is a hydraulic circuit diagram of a front wheel side hydraulic unit in Embodiment 1. FIG. 1 is a hydraulic circuit diagram of a rear wheel side hydraulic unit in Embodiment 1. FIG. 3 is a flowchart showing the contents of motor drive control in the first embodiment. It is a figure which shows the relationship between the rotation direction of the pump motor in Example 1, and the vibration which generate | occur | produces.

  Hereinafter, the best mode for realizing the brake fluid pressure control device of the present invention will be described based on Example 1 shown in the drawings.

First, the brake fluid pressure control device of this embodiment will be described. The hydraulic unit of the first embodiment is provided separately on the front wheel side and the rear wheel side, and a plurality of pump motors are provided in each hydraulic unit. In describing the configuration of the hydraulic unit, the front wheel side will be described as an example.
FIG. 1 is a perspective view of a front wheel side hydraulic unit F / U as viewed from the pump motor side in the brake fluid pressure control unit in the present embodiment. The front wheel side hydraulic unit F / U includes pump motors 12 and 13, a valve unit V / U, and a control unit C / U, which are arranged so as to overlap each other. That is, the pump motors 12 and 13 are assembled in the common housing 4. Further, the rotation direction of the pump motor 12 is B (counterclockwise), and the rotation direction of the pump motor 13 is A (clockwise), that is, they rotate in opposite directions. Details of the rotation of the pump motors 12 and 13 will be described with reference to FIG.

[Hydraulic circuit and control of front wheel side hydraulic unit]
FIG. 2 is a hydraulic circuit diagram of the front wheel side hydraulic unit F / U in the first embodiment. First, the configuration will be described.

  When the brake pedal 1 is depressed, hydraulic pressure is generated in the master cylinder 3. The master cylinder 3 is a so-called tandem type, and can supply the same hydraulic pressure independently to the P system supplied via the oil passage 26 and the S system supplied via the oil passage 27. The master cylinder 3 is provided with a reservoir tank 24 for storing brake fluid.

  A shutoff valve 6 is provided on the oil passage 26, and a shutoff valve 7 is provided on the oil passage 27. A wheel cylinder 8 (FL) is provided on the oil passage communicating from the shutoff valve 6 to the oil passage 26 → the oil passage 28. A wheel cylinder 9 (FR) is provided on the oil passage communicating from the shutoff valve 7 to the oil passage 27 to the oil passage 29.

  A pump 10 is provided on the oil passage 38. A pump 11 is provided on the oil passage 39. The pumps 10 and 11 are driven by pump motors 12 and 13 based on command values from the control unit. In the present embodiment, the pumps 10 and 11 are provided for each wheel, but the configuration may be provided with two or more hydraulic pressure sources, and is not particularly limited.

  An isolation valve 22 is provided between the pumps 10, 11 and the wheel cylinders 8, 9 that can communicate and block the oil passages for each wheel. The isolation valve 22 is in a closed state (so-called normally closed type) when not energized.

  Discharge check valves 18 and 19 are provided on the discharge side of the pumps 10 and 11 in series with the pump. This is so that when the pumps 10 and 11 are driven to supply a necessary amount of hydraulic pressure, the discharge check valves 18 and 19 are provided so that the hydraulic pressure does not return to the pumps 10 and 11 side. Thereby, it becomes possible to hold | maintain a hydraulic pressure, without driving the pumps 10 and 11 any more, and it is comprised so that a hydraulic pressure can be supplied by the drive of the minimum required pumps 10 and 11. FIG.

  A pressure reducing valve 14 is provided on the oil passage 34. A pressure reducing valve 15 is provided on the oil passage 35. When de-energized, the shut-off valves 6 and 7 are opened, and the pressure reducing valves 14 and 15 are closed. When the brake pedal 1 is depressed in this state, the brake switch 2 is set to ON and pressure is generated in the master cylinder 3. The pressure generated in the master cylinder 3 is transmitted to the wheel cylinder 8 in the order of the oil passage 26 → the shut-off valve 6 → the oil passage 28. Further, the oil is transmitted to the wheel cylinder 9 in the order of the oil passage 27 → the shut-off valve 7 → the oil passage 29.

  A relief valve 16 is provided on the oil passage 36. A relief valve 17 is provided on the oil passage 37. The allowable hydraulic pressure value of the relief valves 16 and 17 is set to the required maximum hydraulic pressure in the hydraulic circuit.

(Brake-by-wire control in front wheel side hydraulic unit F / U)
The front wheel side hydraulic unit F / U in this embodiment performs so-called brake-by-wire control. That is, when the IGN is turned on by the driver's key operation, the shutoff valves 6 and 7 are closed. Then, the driver's intention to operate the brake is detected from the master cylinder pressure or the like, and a desired brake fluid pressure is generated by the pumps 10 and 11 in accordance with the intention and traveling conditions.

  Here, when the pumps 10 and 11 are driven, the brake fluid is sucked from the reservoir tank 24 and pressurized. The pressurized brake fluid pressurizes the inside of the wheel cylinder 8 through the oil passages 28, 30, 32 and 38. Further, the inside of the wheel cylinder 9 is pressurized through the oil passages 29, 31, 33 and 39. The generated brake fluid pressure is detected by the wheel cylinder pressure sensors 20 and 21. The master cylinder pressure can be detected by a master cylinder pressure sensor, a stroke sensor, or the like, but is not limited to these, and other means may be used.

(ABS control)
When the driver depresses the brake pedal 1 and the braking force is input to the front wheel side wheel cylinders 8 and 9, when the wheel lock is detected by a wheel speed sensor or the like, the front wheel side wheel cylinder pressure is controlled. Thus, ABS control can be performed. That is, the shutoff valves 6 and 7 are closed, the pressure reducing valves 14 and 15 are opened, the pressure is reduced, and the pressure reducing valves 14 and 15 are closed to maintain the hydraulic pressure and the shutoff valves 6 and 7 are opened. The pressure can be increased by this, and ABS control can be achieved.

(TCS control)
When the slip state of the front wheel is detected by a wheel speed sensor or the like, TCS control can be performed by controlling the front wheel side wheel cylinder pressure. That is, the shutoff valves 6 and 7 are closed, the pump motors 12 and 13 and the pumps 10 and 11 are driven, and the pressure is increased from the reservoir tank 24 via the flexible hose 41 and the pumps 10 and 11. In addition, the hydraulic pressure can be maintained by stopping the pumps 10 and 11, and the pressure can be reduced by opening the pressure reducing valves 14 and 15, and TCS control can be achieved.

(Spin prevention control)
By providing a sensor that detects the spin direction of the vehicle, such as a yaw rate sensor, and performing the same control as the above TCS control, the spin prevention control can be performed.

  In the front wheel side hydraulic unit F / U of the present embodiment, by using the housing 4 in common, the hydraulic units can be combined into one, so that the number of hydraulic units can be reduced. As a result, the number of parts can be reduced, and the cost can be reduced. Further, the proportion of the hydraulic unit in the brake fluid pressure control device can be reduced, and space saving and weight reduction can be achieved.

[Hydraulic circuit and control of rear wheel side hydraulic unit]
FIG. 3 is a hydraulic circuit diagram of the rear wheel side hydraulic unit R / U. Since the external appearance is basically the same as that of the front wheel side hydraulic unit F / U, description thereof is omitted. First, the configuration will be described.

  The wheel cylinders 52 (RL) and 53 (RR) that generate braking force on each of the rear wheels are not directly connected to the master cylinder 3. It consists of shut-off valves 50 and 51 and pressure reducing valves 58 and 59 which are hydraulic pressure control valves capable of increasing and maintaining the hydraulic pressure of each wheel cylinder 52 and 53. Further, the rear wheel side hydraulic unit R / U is connected to the reservoir tank 24 via the flexible hose 71.

  The hydraulic pressure control of each wheel cylinder 52, 53 will be described. When the pressure is increased, the shut-off valves 50 and 51 are opened, and the brake fluid temporarily passes from the reservoir tank 24 to the diaphragms 72 and 73 via the flexible hose 71, the shut-off valves 50 and 51, and the oil passages 78 and 81. Is accumulated in the oil passages 79 and 82. By driving the pump motors 56 and 57 to drive the pumps 54 and 55, the brake fluid is supplied to the wheel cylinders 52 and 53 via the oil passages 75 and 77. In the present embodiment, plunger pumps are applied as the pumps 54 and 55.

  Unlike the pressure reducing valves 14 and 15 on the front wheel side, the pressure reducing valves 58 and 59 are normally open valves. The normally open valve prevents the brake fluid from being contained in the wheel cylinder and generating unnecessary braking force when the rear wheel is fail-safe and the system is shut off during braking.

  The pumps 54 and 55 are driven by pump motors 56 and 57 based on a command value from a control unit calculated in accordance with a brake operation. Then, the pump motors 56 and 57 are driven so that the pressure detected by the wheel cylinder pressure sensors 69 and 70 becomes an appropriate value.

  Here, suction check valves 67 and 68 are provided on the pump suction side, and discharge check valves 65 and 66 are provided on the discharge side. On the discharge side, pulse pressure reducing orifices 63 and 64 are provided. Furthermore, relief valves 61 and 62 are provided on the oil passages 80 and 83. The allowable value of the relief valves 61 and 62 is set to a necessary maximum hydraulic pressure value in the hydraulic circuit.

  The isolation valve 60 is in a valve open state (so-called normal open type) when not energized (OFF), and shuts off the oil path on the right rear wheel side and the left rear wheel side. By closing the isolation valve 60, the hydraulic pressure generated in the pumps 54 and 55 can be supplied independently to the left and right wheels. That is, even when a failure occurs in the oil passage communicating with one of the wheel cylinders and the system is shut off, the left and right wheel cylinders 53, 53 and the master cylinder 3 are secured as independent hydraulic circuits by the isolation valve 60. Therefore, at least one wheel can generate a braking force, and safety can be ensured.

  In the rear wheel side hydraulic unit R / U, as with the front wheel side hydraulic unit F / U, by controlling the shutoff valves 50 and 51 and the pressure reducing valves 58 and 59, brake-by-wire control, ABS control, TCS control, Control such as anti-spin control can be performed.

  That is, in the rear wheel side hydraulic unit R / U as well as the front wheel side hydraulic unit F / U, the number of hydraulic units can be reduced by making the housing 4 common. Therefore, the cost can be reduced by reducing the number of parts, and the proportion of the hydraulic unit in the brake fluid pressure control device can be reduced, thereby saving space and weight.

  Further, since the rear wheel side hydraulic unit R / U is connected to the reservoir tank 24 provided in the master cylinder 3 by the flexible hose 71, the sound vibration to the master cylinder 3 side is compared with the case where it is connected by a steel pipe. Can be suppressed.

[Details of pump motor drive control]
Next, taking the front wheel side hydraulic unit F / U as an example, the contents of the pump motor drive control will be described. FIG. 4 is a flowchart showing the contents of motor drive control in the first embodiment.

  In step 101, a self-check is performed to determine whether both pump motors 12 and 13 rotate. If both rotate, proceed to step 102. Otherwise, the process proceeds to step 112, a fail safe mode operation is performed, and this control flow is terminated.

  In step 102, the driver's brake operation is detected.

  In step 103, the vehicle body condition is detected by a yaw rate sensor or the like, and it is confirmed whether an independent control amount is required for each of the left and right wheels. If independent control amounts are required for the left and right wheels, the process proceeds to step 104. Otherwise, the process proceeds to step 107.

  In step 104, the isolation valve 22 is closed and the routine proceeds to step 105.

  In step 105, the necessary hydraulic pressure increase amount for each wheel is determined by a microcomputer or the like, and the process proceeds to step 106.

  In step 106, both pump motors 12 and 13 are operated, and the routine proceeds to step 111. The pump motors 12 and 13 are respectively operated in reverse rotation.

  In step 107, the isolation valve 107 is opened and the routine proceeds to step.

  In step 108, a necessary increase in hydraulic pressure is determined for each wheel by a microcomputer or the like, and the process proceeds to step 109.

  In step 109, it is determined whether the requested hydraulic pressure is higher than a threshold value. When it is higher than the threshold value, the routine proceeds to step 106 and both the pump motors 12 and 13 are operated. If it is lower than the threshold, only one of the pump motors 12 and 13 is operated, and the routine proceeds to step 111.

  In step 111, the required brake amount for each wheel is increased, and this control flow ends.

  That is, when two pump motors are used, there are two types: 1) when it is necessary to control the left and right wheels independently, and 2) when there is a large amount of required hydraulic pressure. When these two pump motors are used, they are rotated in directions opposite to each other. Details regarding the rotation direction of the pump motor will be described later with reference to FIG.

[Relationship between rotation direction of pump motor and generated vibration]
FIG. 5 is a diagram illustrating a relationship between the rotation direction of the pump motor and the generated vibration in the first embodiment. The front wheel side hydraulic unit F / U will be described as an example. The same relationship is established in the rear wheel side hydraulic unit R / U. Here, the amount of torque generated in the rotation direction A is Ta, and the amount of torque generated in the rotation direction B is -Tb.

  FIG. 5A is a diagram illustrating a case where the rotation directions of the pump motors 12 and 13 are the same. The torque amount received by the entire front wheel side hydraulic unit F / U by the rotation of the pump motors 12 and 13 is Ta + Ta, that is, the sum of the torque amounts generated by the two pump motors is the vibration source from the front wheel side hydraulic unit F / U. Become. The vibration is transmitted to the passenger compartment through the oil passages 26 and 27.

  FIG. 5B is a diagram illustrating a case where the rotation directions of the pump motors 12 and 13 are opposite. The amount of torque received by the entire front wheel side hydraulic unit F / U due to the rotation of the pump motors 12 and 13 is Ta-Tb. That is, the torque amount Ta caused by the pump motor 12 and the torque amount Tb caused by the pump motor 13 can be offset each other. For this reason, it is possible to reduce the amount of torque received by the front wheel side hydraulic unit F / U as compared with the case where at least the rotation directions of the pump motors 12 and 13 are the same, and the torque is transmitted to the vehicle interior via the oil passages 26 and 27. Vibration can be suppressed. The above effect can be achieved because the two pump motors 12 and 13 share the housing 4.

  As described above, the brake hydraulic pressure control device according to the first embodiment is configured by the front wheel side hydraulic unit F / U and the rear wheel side hydraulic unit R / U. In each hydraulic unit, the housing of two pump motors. 4 is common, and the pump motors are driven to rotate in opposite directions when the pump motor is operated.

  Thereby, the torque amounts resulting from the two pump motors can be canceled out. Therefore, in the front wheel side hydraulic unit F / U, it is possible to reduce the amount of torque received by the front wheel side hydraulic unit F / U compared to the case where the rotation directions of at least two pump motors 12 and 13 are the same. Vibration transmitted to the vehicle interior via the roads 26 and 27 can be suppressed. In the rear wheel side hydraulic unit R / U, since the hydraulic unit and the master cylinder 3 side are connected by the flexible hose 71, the influence of the sound vibration transmitted to the vehicle interior by driving the pump motors 56 and 57 is further reduced. be able to.

  Moreover, the number of hydraulic units can be reduced by combining the hydraulic units into one on each of the front wheel side and the rear wheel side. As a result, the number of parts can be reduced, and the cost can be reduced. Further, the proportion of the hydraulic unit in the brake fluid pressure control device can be reduced, and space saving and weight reduction can be achieved.

  In the first embodiment, the front wheel side hydraulic unit F / U and the rear wheel side hydraulic unit R / U are separated from each other. However, both may be combined into one. In this configuration, four pump motors are included in total, but if at least one pump motor rotates in a direction opposite to the other pump motors, all pump motors rotate in the same direction. Sound vibration can be suppressed as compared with the case of doing so.

  Further, technical ideas other than the claims that can be grasped from the respective embodiments will be described below together with the effects thereof.

(A) In the brake fluid pressure control device according to claim 1,
A brake fluid pressure control device that performs brake-by-wire control that performs fluid pressure control by driving a pump motor during braking.

  In brake-by-wire control, pressurization is performed by driving a pump motor during normal braking. That is, since vibration can be suppressed during normal braking where the pump motor is frequently used, the sound vibration suppression effect can be enhanced.

1 Brake pedal 2 Brake switch 3 Master cylinder 4 Housing 6, 7 Shut-off valve 8 Wheel cylinder (FL)
9 Wheel cylinder (FR)
10, 11 Pump 12, 13 Pump motor 14, 15 Pressure reducing valve 16, 17 Relief valve 18, 19 Discharge check valve 20, 21 Wheel cylinder pressure sensor 22 Isolation valve 24 Reservoir tank 26, 27 Oil passage 41 Flexible hose 50, 51 Shut-off valve 52 Wheel cylinder (RL)
53 Wheel cylinder (RR)
54, 55 Pump 56, 57 Pump motor 58, 59 Pressure reducing valve 60 Isolation valve 61, 62 Relief valve 63, 64 Pulse pressure reducing orifice 65, 66 Discharge check valve 67, 68 Suction check valve 69, 70 Wheel cylinder pressure sensor 71 Flexible hose 72, 73 Diaphragm

Claims (2)

Two rotationally driven pump motors that are assembled to the housing so that their rotational axes are in the same direction and can be driven independently;
Two sets of pumps provided in the housing and driven by the pump motors;
A control unit assembled to the housing and capable of rotating the pump motors to pressurize the brake fluid and pressurize a plurality of wheel cylinders provided in the vehicle,
The control unit rotationally drives the pump motors based on a command value calculated according to a driver's brake operation. When the required hydraulic pressure for the wheel cylinder is higher than a set hydraulic pressure, the motors The brake hydraulic pressure control apparatus is characterized in that the wheel cylinders are rotated in the opposite directions, and when the pressure is low, one of the rotationally driven pump motors is rotated to pressurize the wheel cylinder. In the brake fluid pressure control device according to claim 1,
The housing includes an oil passage for supplying brake fluid from a reservoir tank provided in the master cylinder to the pump,
The brake hydraulic pressure control device, wherein the reservoir tank and the oil passage are connected by a flexible hose.

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