JP2000219124A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and to efficiently use energy. SOLUTION: This brake device receives hydraulic pressure of a master cylinder and hydraulic pressure of wheel cylinder with different areas and from the different directions. The brake device is provided with a piston 37 to be moved to one side when the hydraulic pressure having the specified times in the area ratio exceeds hydraulic pressure of the wheel cylinder, a valve 52 for shutting off the communication between the master cylinder and the wheel cylinder when the piston 37 is moved to one side, a detecting means 49 for detecting the movement of the piston 37, and a control means for driving a pump 16 when the detecting means 49 detects that the piston 37 is moved to one side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for controlling a hydraulic pressure obtained by a pump based on an input from a brake pedal to obtain a braking force.

[0002]

2. Description of the Related Art Hydraulic pressure obtained by a pump is used as a brake device for a hybrid engine vehicle that obtains driving force by using both an internal combustion engine and an electric motor and an electric vehicle that obtains driving force only by an electric motor. It is preferable to use one that obtains a braking force by controlling based on an input from a brake pedal, and various such brake devices have been developed.
An example is shown in FIG. The brake device includes a brake pedal 200, a pedaling force sensor 201 for detecting an input to the brake pedal 200, and a master cylinder 202 for generating a brake fluid pressure based on an input from the brake pedal 200.
And a stroke simulator 20 for absorbing the brake fluid pressure generated by the master cylinder 202 and applying a reaction force corresponding to the depression to the brake pedal 200.
3 and the brake fluid pressure generated in the master cylinder 202 when the system failed,
And an NC valve 204 for preventing the gas from being introduced into the control valve 3. Further, a reservoir tank 205 for storing brake fluid is provided.
A pump 206 for generating brake fluid pressure by sucking brake fluid from the reservoir tank 205;
An accumulator 207 for storing the brake fluid pressure generated in 6 and a relief valve 208 for releasing the fluid pressure on the accumulator 207 side to the reservoir tank 205 side as needed. Further, calipers 209, 209,... Provided for each wheel to generate a braking force, and provided for each of the calipers 209, 209,... To control the communication between the corresponding caliper 209 and the accumulator 207. An electromagnetic switching type pressure increasing valve 210 for controlling the pressure of the brake fluid supplied to the caliper 209
Are provided for each of the calipers 209, 209,..., And are electromagnetically switched decompression for controlling the communication between the corresponding calipers 209 and the reservoir tank 205 to reduce the brake fluid pressure supplied to the calipers 209. Are provided for each of the calipers 209, 209,..., And are electromagnetically switched switching valves 212 for switching the supply source of the brake fluid pressure to the corresponding calipers 209 to one of the master cylinder 202 and the accumulator 207. And In addition, each caliper 209,
,.., 209,... Each of which detects a brake fluid pressure of the corresponding caliper 209.
, And a pressure sensor 214 provided between the relief valve 208 and the pressure-intensifying valves 210, 210,. In such a brake device, the output from the treading force sensor 201 is mainly used as a command signal, and the output from the pressure sensors 213, 213,... Provided in the calipers 209, 209,. , Pressure reducing valve 2
, And the switching valves 212, 212,... Are switched.

[0003]

As described above, a conventional brake device which obtains a braking force by controlling a hydraulic pressure obtained by a pump based on an input of a brake pedal has a large number of parts and is required for piping and wiring. There was a problem that it took time. In addition, while the required pressure is about 3 MPa in a normal brake operation with a deceleration of about 0.3 G, in the above-mentioned conventional apparatus, a high pressure of 13 to 20 MPa is generated by a pump, and the pressure is reduced by a solenoid valve to reduce the caliper. And thus there is a problem that a large amount of energy is wasted. Therefore, the present invention can reduce the number of components and efficiently use energy in a brake device that obtains a braking force by controlling a hydraulic pressure obtained by a pump based on an input of a brake pedal. It is an object of the present invention to provide a brake device that can perform the braking.

[0004]

According to a first aspect of the present invention, there is provided a brake device comprising: a master cylinder for generating a hydraulic pressure according to an input of a brake pedal; A wheel cylinder for generating a braking force, a pump for generating a hydraulic pressure to be introduced into the wheel cylinder, and a hydraulic cylinder for receiving the hydraulic pressure of the master cylinder and the hydraulic pressure of the wheel cylinder from different directions in different areas, respectively, and When the hydraulic pressure of the master cylinder multiplied by a predetermined value exceeds the hydraulic pressure of the wheel cylinder, the hydraulic cylinder moves to one side. A piston that moves to the opposite side when the pressure drops below
When the piston moves to the one side, the communication between the master cylinder and the wheel cylinder is cut off, while when the piston moves to the opposite side, a valve that connects the master cylinder to the wheel cylinder, Detecting means for detecting the position, and driving the pump in a state where the movement of the piston to the one side is detected by the detecting means, while detecting the movement of the piston to the opposite side by the detecting means; And a control means for stopping the driving of the pump in the closed state. As a result, when the brake pedal is depressed, the hydraulic pressure generated in the master cylinder increases, and when the hydraulic pressure of the master cylinder, which is a predetermined multiple of the area ratio of the piston, becomes greater than the hydraulic pressure of the wheel cylinder, the piston moves to one side. Go to Then, while the valve is closed to cut off the communication between the master cylinder and the wheel cylinder, the detection means detects the movement of the piston to the one side, so that the control means drives the pump. As a result, the brake fluid discharged from the pump is introduced into the wheel cylinder without being released to the master cylinder side by the valve, and the braking force increases. On the other hand, when the brake pedal is released and the hydraulic pressure generated in the master cylinder decreases, and the hydraulic pressure of the master cylinder, which has been multiplied by a predetermined value by the area ratio of the piston, becomes lower than the hydraulic pressure of the wheel cylinder, the piston moves to the opposite side. Moving. Then, while the valve is opened and the hydraulic pressure of the wheel cylinder is returned to the master cylinder, the detection means detects the movement of the piston to the opposite side, so the control means stops the pump. As a result, the brake fluid is released to the master cylinder side via the valve, and the braking force is reduced.

According to a second aspect of the present invention, there is provided a brake device comprising:
The pump according to claim 1, wherein the pump generates a hydraulic pressure by reciprocating the plunger, and the plunger is driven by a magnetic force by a voice coil motor. As described above, since the plunger pump that reciprocates the plunger by the magnetic force using the voice coil motor is used as the pump, the thrust within the stroke can be made constant and high-speed response can be achieved.

According to a third aspect of the present invention, there is provided a brake device comprising:
The brake device according to claim 1 or 2, further comprising an actuator capable of forcibly moving the piston. As a result, the brake pedal is depressed, and the hydraulic pressure generated in the master cylinder increases,
Even if the hydraulic pressure of the master cylinder, which has been multiplied by a predetermined value in the area ratio of the piston, is higher than the hydraulic pressure of the wheel cylinder, the valve is opened by forcibly moving the piston to the opposite side by the actuator, thereby opening the master cylinder. And the wheel cylinder can communicate with each other, and the hydraulic pressure of the wheel cylinder can be released to the master cylinder side.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brake device according to a first embodiment of the present invention will be described below with reference to FIGS. First
As shown in FIG. 1, the brake device 11 according to the embodiment has a brake pedal 1 to which an operation amount is input by a driver.
2, a master cylinder 13 for generating a hydraulic pressure (control target hydraulic pressure) according to the input of the brake pedal 12, a reservoir tank 14 for storing the brake fluid and supplying the brake fluid to the master cylinder 13, It has a wheel cylinder 15 of a brake caliper that generates a braking force by hydraulic pressure, and a pump 16 that generates a hydraulic pressure that sucks brake fluid from a reservoir tank 14 via a master cylinder 13 and introduces the brake fluid into the wheel cylinder 15. .

Further, the brake device 11 compares the hydraulic pressure of the master cylinder 13 with the hydraulic pressure of the wheel cylinder 15 to output a signal, and controls the pressure for controlling the communication between the master cylinder 13 and the wheel cylinder 15 and the cutoff of the communication. A detection / decompression mechanism 17, a control circuit (control means) 18 for controlling the driving of the pump 16 based on a signal from the pressure detection / decompression mechanism 17, and a power supply to the control circuit 18. A vehicle-body-side ECU (vehicle motion control device) 19 for exchanging signals such as a wheel cylinder pressure signal as a monitoring signal of a braking force, and a low pressure (almost atmospheric pressure) capable of storing brake fluid. And an in-wheel reservoir.

The wheel cylinder 15, the pump 16, the pressure detecting / reducing mechanism 17, the in-wheel reservoir and the control circuit 18 are provided with a wheel brake 2 attached to the wheel.
0, and this wheel brake 20 is provided for each wheel, although not shown.

The pressure detecting / reducing mechanism 17 will be further described with reference to FIG. The pressure detecting / reducing mechanism 17 has a cylinder 22. The cylinder 22 has a small-diameter hole 23 formed at one end thereof, an intermediate-diameter hole 24 formed coaxially with and adjacent to the small-diameter hole 23 and having a larger diameter than the small-diameter hole 23. A stepped cylinder hole 26 having a large-diameter hole 25 larger in diameter than the intermediate-diameter hole 24 formed coaxially on the opposite side of the small-diameter hole 23 of the large-diameter hole 24 is formed. ing.

The cylinder 22 has one end opening at a predetermined position opposite to the intermediate diameter hole 24 of the large diameter hole 25 of the cylinder hole 26, and the other end opening outside the cylinder 22. As described above, the master cylinder communication passage 28 is formed orthogonal to the large diameter hole 25, and the master cylinder communication passage 28 is communicated with the master cylinder 13.

The cylinder 22 has a cylinder hole 26.
The large-diameter hole 25 is perpendicular to the large-diameter hole 25 so that one end is opened at a predetermined position opposite to the intermediate-diameter hole 24 and the other end is opened outside the cylinder 22. Thus, a suction-side communication passage 29 is formed.
Is connected to the suction side of the pump 16 via an external communication passage 30 outside the cylinder 22.

In addition, the cylinder 22 has a cylinder bore 2
6 so that one end opening is opened at a predetermined position opposite to the large diameter hole 25 of the intermediate diameter hole 24 and the other end is opened outside the cylinder 22. At right angles, a discharge-side communication passage 31 is formed, and the discharge-side communication passage 31 is communicated with the discharge side of the pump 16 via an external communication passage 32 outside the cylinder 22.

The cylinder 22 has a cylinder hole 26.
The middle diameter hole 24 is orthogonal to the middle diameter hole 24 so that one end is opened at a predetermined position opposite to the large diameter hole 25 and the other end is opened outside the cylinder 22. do it,
A wheel cylinder communication passage 33 is formed, and the wheel cylinder communication passage 33 is communicated with the wheel cylinder 15.

Further, the cylinder 22 has a cylinder bore 2
6 is perpendicular to the large-diameter hole 25 so that one end of the large-diameter hole 25 opens at a predetermined position on the side of the intermediate-diameter hole 24 and the other end opens to the outside of the cylinder 22. A reservoir communication passage 34 communicating with a not-shown in-wheel reservoir is formed. In addition, the cylinder 22 is formed with an internal communication passage 35 having an opening at one end at a predetermined position intermediate the small-diameter hole 23 of the cylinder hole 26 and an opening at the other end in the reservoir communication passage 34.

A stepped piston 37 is slidably inserted into the large-diameter hole portion 25 and the intermediate-diameter hole portion 24 of the cylinder hole 26. The piston 37 has a large-diameter shaft portion 38 and a small-diameter shaft portion 39 formed coaxially and adjacent to the large-diameter shaft portion 38 and having a smaller diameter than the large-diameter shaft portion 38. The shaft 38 is disposed in the cylinder hole 26 such that the shaft 38 is located in the large-diameter hole 25 and the small-diameter shaft 39 is substantially located in the intermediate-diameter hole 24.

At the center of the piston 37, a communication hole 40 is provided.
Are formed. The communication hole 40 includes a large-diameter communication hole 41 formed from the end face on the large-diameter shaft portion 38 side and a small-diameter shaft portion 3.
The small-diameter communication hole 42 has a smaller diameter than the large-diameter communication hole 41 formed from the end face on the 9th side. Here, the opposite end of the small-diameter communication hole portion 42 to the large-diameter communication hole portion 41 includes:
A tapered valve seat 43 whose diameter increases at the tip end is formed. Therefore, the valve seat 43 is provided with a throttle.

A ring-shaped cup seal 45 which is slidable with respect to the large-diameter hole 25 and opens and closes a gap with the large-diameter hole 25 is fixed to the large-diameter shaft 38. This cup seal 45 always exists between the master cylinder communication passage 28 and the reservoir communication passage 34 regardless of the position of the piston 37. When the hydraulic pressure is higher than the hydraulic pressure, the closed state is established. When the hydraulic pressure in the master cylinder communication path 28 is lower than the hydraulic pressure in the reservoir communication path 34, the opened state is established.

A ring-shaped cup seal 46 which is slidable with respect to the intermediate diameter hole 24 and opens and closes a gap with the intermediate diameter hole 24 is fixed to the small diameter shaft 39. The cup seal 46 always exists between the wheel cylinder communication passage 33 and the reservoir communication passage 34 regardless of the position of the piston 37. When the hydraulic pressure is higher than the hydraulic pressure, the closed state is established, and when the hydraulic pressure in the wheel cylinder communication path 33 is lower than the hydraulic pressure in the reservoir communication path 34, the opened state is set.

The large-diameter shaft portion 38 and the small-diameter shaft portion 3 of the piston 37
9 and a step between the large-diameter hole 25 of the cylinder hole 26 and the intermediate-diameter hole 24, the piston 37 is positioned at the moving end on the large-diameter hole 25 side. There is provided a piston spring 47 which is urged by a weak urging force so as to cause the piston spring 47 to urge.

A stroke sensor (detection means) 49 is mounted on the small-diameter hole 23 side of the cylinder 22.
The stroke sensor 49 has a sensor main body 50 attached to the cylinder 22 and a valve body 51 which is inserted into the cylinder hole 26 from the sensor main body 50 and faces the valve seat 43 and has a smaller diameter than the small diameter hole 23. ing. This valve element 51
Is movable within an extremely small range in the axial direction, and the distal end abuts and separates from the valve seat 43 of the piston 37 so that the communication hole 40 of the piston 37 can be closed and opened. Together with 43, a pressure reducing valve (valve) 52 is constituted.

The sensor body 50 movably supports the valve element 51 and detects the position of the valve element 51.
A valve body spring (not shown) for urging the valve body 51 with a strong urging force in a direction protruding from the sensor body 50 to abut the valve body 51 against a forward end stopper (not shown), and the valve body 51 It has a switch (not shown) that is turned off when the vehicle is advanced, and is turned on when the valve element 51 moves toward the retreating end of the sensor body 50.

Here, specifically, the switch is located at a position where the piston 37 and the valve element 51 are in contact with each other and the valve element 51 is further moved by a predetermined amount toward the sensor main body 50 in a state where the pressure reducing valve 52 is closed (however, The switch position is located before the moving end in this direction), and is switched from OFF to ON when the valve body 51 passes through the switch position while moving in the direction of the sensor body 50.
, And is switched from ON to OFF when passing through this switching position while moving in the reverse direction. In the small-diameter hole portion 23 of the cylinder hole 26, a pair of ring-shaped seal members 54 and 55 that are slidable with respect to the valve body 51 and close a gap with the valve body 51 are provided with an internal communication passage. 35 is fixed so as to sandwich the opening.

As described above, the piston 37 receives the hydraulic pressure of the master cylinder 13 and the hydraulic pressure of the wheel cylinder 15 in different areas (master cylinder side area> wheel cylinder side area) from opposite directions, and the area ratio between these areas. When the hydraulic pressure of the master cylinder 13 multiplied by the predetermined value exceeds the hydraulic pressure of the wheel cylinder 15, the hydraulic cylinder moves toward one side close to the stroke sensor 49, while the hydraulic pressure of the master cylinder 13 multiplied by a predetermined ratio in the area ratio is increased. When the pressure becomes lower than the hydraulic pressure of the wheel cylinder 15, it moves toward the opposite side away from the stroke sensor 49.

Specifically, the pressure of the master cylinder 13 is Pm, the effective area of the piston 37 on the master cylinder 13 side is Sa, the pressure of the wheel cylinder 15 is Pw, the effective area of the piston 37 on the wheel cylinder 15 side is Sb, Assuming that the effective pressure receiving area of the valve element 51 is Sz and the sliding resistance and the spring reaction force are Fs, the pressure from the in-wheel reservoir is almost 0, and therefore the balance of the force of the piston 37 is expressed by the following equation. F = Pm × Sa−Pw × (Sb−Sz) −Fs

When the force F is positive, the piston 37 moves toward the one side in the direction of the stroke sensor 49. Then, the pressure reducing valve 52 is closed by bringing the valve seat 43 into contact with the valve element 51 of the stroke sensor 49 to cut off the communication between the master cylinder 13 and the wheel cylinder 14, and the valve element 51 is moved toward the sensor body 50. The sensor is moved to output an ON signal to the switch of the sensor main body 50.

On the other hand, when the force F is smaller than 0, the piston 37 moves toward the opposite side, which is away from the stroke sensor 49. Then, the movement of the valve body 51 in contact with the piston 37 to the opposite side to the sensor body 50 causes the switch of the sensor body 50 to output an OFF signal. The pressure reducing valve 52 is opened by separating from the valve body 51, and the master cylinder 13 and the wheel cylinder 15 are communicated through the communication hole 40.

The control circuit 18 drives the pump 16 when the ON signal is output from the switch of the sensor body 50, that is, when the stroke sensor 49 detects that the piston 37 has moved to the one side, When the OFF signal is output from the sensor main body 50, that is, when the stroke sensor 49 detects that the piston 37 has moved to the opposite side, the pump 16 is controlled to stop driving.

The reservoir communication passage 34 accumulates the leakage from the cup seals 45 and 46 due to the brake fluid and the wheel cylinder pressure corresponding to the area of the intermediate portion of the piston 37 × the stroke, and the hydraulic pressure of the master cylinder 13 is applied to the reservoir communication passage 34. When the fluid pressure falls below the predetermined value, the brake fluid is returned to the master cylinder 13 via the cup seals 45 and 46. The in-wheel reservoir is preferably formed of bellows or the like in order to prevent leakage of brake fluid. The reservoir communication passage 34 may be open to the atmosphere instead of communicating with the in-wheel reservoir.

The amount of liquid consumed by the wheel cylinder 15 is about 2 cc per wheel, but the pump 16 must be able to obtain a hydraulic pressure of 10 MPa or more in the shortest possible time during rapid braking. A small discharge, high pressure plunger pump with low leakage and high volumetric efficiency is used. That is, the pump 16 includes an eccentric cam 57, a plunger 58 that reciprocates by the rotation of the eccentric cam 57, and a liquid chamber 59 whose volume increases and decreases by reciprocation of the plunger 58.
A suction-side check valve 60 that allows only the flow of the liquid from the master cylinder communication passage 28, the suction-side communication passage 29, and the external communication passage 30 to the liquid chamber 59;
2. Discharge side communication passage 31 and wheel cylinder communication passage 3
3 and a discharge-side check valve 61 that allows only the flow of the liquid to the discharge port 3.

The control circuit 18 drives the pump 16 when the stroke sensor 49 detects that the piston 37 has moved to the one side. On the other hand, when the stroke sensor 49 detects that the piston 37 has moved to the opposite side, the driving of the pump 16 is stopped.

The brake device 1 according to the first embodiment described above.
1 will be described with reference to FIG. FIG. 3A shows the ON / OFF state of the pump 16 with respect to the stroke position of the piston 37, and FIG.
7 shows the open / closed state of the pressure reducing valve 52 with respect to the stroke position 7, and FIG. 3C shows the state of the resultant force of the spring reaction force and the valve body reaction force with respect to the stroke position of the piston 37.

When the brake pedal 12 is depressed, the hydraulic pressure generated in the master cylinder 13 increases, and the piston 37
Is greater than the hydraulic pressure of the wheel cylinder 15 (i.e., the master cylinder generated by the input of the brake pedal 12 which is a command for obtaining the required braking force). When the wheel cylinder pressure corresponding to the pressure becomes higher than the wheel cylinder pressure at that time), the piston 37 starts to move toward the one side (position S1 in FIG. 3).

When the piston 37 moves by a predetermined amount toward the one side, the valve seat 43 of the piston 37 comes into contact with the valve element 51 of the stroke sensor 49, and the communication hole 40 is closed by the pressure reducing valve 52 composed of these. Then, the communication between the master cylinder 13 and the wheel cylinder 15 is cut off (position S2 in FIG. 3). Further, when the piston 37 moves by a predetermined amount toward the one side together with the valve element 51, a switch in the sensor main body 50 is turned on. Then, the control circuit 18 starts driving the pump 16 based on the ON signal (position S3 in FIG. 3). As a result, the brake fluid discharged from the pump 16 is introduced into the wheel cylinder 15 without being released to the master cylinder 13 side, and the braking force increases. Thereafter, the piston 37 moves to the one moving end together with the valve element 51 and stops (position S4 in FIG. 3).

On the other hand, from this state, the brake pedal 12
Is reduced, the hydraulic pressure generated in the master cylinder 13 decreases, and the hydraulic pressure of the master cylinder 13, which is a predetermined multiple of the area ratio of the piston 37, becomes smaller than the hydraulic pressure of the wheel cylinder 15 (required braking force) When the wheel cylinder pressure corresponding to the master cylinder pressure generated by the input of the brake pedal 12 as a command for obtaining the pressure becomes lower than the wheel cylinder pressure at that time), the piston 37 starts to move toward the opposite side.

Then, the valve element 51 moves toward the opposite side by the valve element spring together with the piston 37, and the sensor body 5
The switch 0 is turned off, and the control circuit 18 stops the pump 16 based on the OFF signal. Further, when the piston 37 moves toward the opposite side, the piston 37 separates from the valve body 51 and the pressure reducing valve 52 constituted by these opens the communication hole 40, and the hydraulic pressure of the wheel cylinder 15 is moved to the master cylinder 13 side. return. As a result, the brake fluid is released to the master cylinder 13 via the pressure reducing valve 52, and the braking force is reduced. When the hydraulic pressure of the wheel cylinder 15 is reduced, the brake fluid supplied to the wheel cylinder 15 is returned to the master cylinder 13, so that the brake pedal 12 is pushed back as the pedaling force is reduced.

The brake device 1 according to the first embodiment described above.
According to No. 1, the pump, accumulator and pressure control unit on the vehicle body side can be reduced and the number of parts can be reduced as compared with the conventional device for controlling the hydraulic pressure obtained by the pump to obtain the braking force.・ Easy wiring. Also, since the pump 16 is driven after the hydraulic pressure on the wheel cylinder 15 side needs to be increased, energy is used more efficiently than in the conventional method in which a high pressure for emergency is constantly generated and the pressure is reduced by the pressure reducing valve. can do. Further, the pressure and the amount of fluid required for braking can be obtained in the wheel brake 20, which is a place where the hydraulic pressure is consumed. Further, since the piston 37 for detecting the pressure constitutes a part of the pressure reducing valve 52, the number of parts can be reduced.

Here, the use of a plunger pump as the pump 16 allows the brake fluid from the master cylinder 13 to receive the suction-side check valve 60, the liquid chamber 59 and the discharge-side reverse even during the delay of the pump 16 startup. Since the liquid is supplied to the wheel cylinder 15 via the stop valve 61, the initial liquid amount due to the invalid stroke of the wheel cylinder 15 can be rapidly filled.

A rod is extended from the piston 37, and a voice coil motor or a solenoid, etc., capable of forcibly moving the piston 37 through the rod in a direction to cancel the pressure from the master cylinder 13 to force the piston 37 to move. May be provided. With this configuration,
When the brake pedal 12 is depressed, the master cylinder 13
Even if the hydraulic pressure of the master cylinder 13, which is multiplied by a predetermined value in the area ratio of the piston 37, is greater than the hydraulic pressure of the wheel cylinder 15, the piston 37 is moved by the actuator to the opposite side. , The pressure reducing valve 52 is opened to allow the master cylinder 13 and the wheel cylinder 15 to communicate with each other, and the hydraulic pressure of the wheel cylinder 15 can be released to the master cylinder 13 side. Therefore, the present invention can be applied to a system in which the braking force must be forcibly reduced, such as ABS.

In this case, when an ABS pressure reduction command signal is output from the vehicle body side ECU 19, the control circuit 18 responds thereto.
Applies a biasing force to the piston 37 with an actuator to open the pressure reducing valve 52. At this time, the pressure of the wheel cylinder 15 does not drop below the pressure of the master cylinder 13, but since the boosting ratio of the vacuum booster which is normally used is 4 times or more, the braking force is reduced to 1/4. The following can be lowered, ABS
Function can be secured.

Next, a brake device according to a second embodiment of the present invention will be described below with reference to FIG. 4, focusing on differences from the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. First
When a pump of the type that reciprocates the plunger 58 by electrically rotating the eccentric cam 57 as in the embodiment is used, there is room for further improvement in improving the high-speed response. The embodiment improves this point. That is, in the second embodiment, in order to respond at a high speed, the pump 16 that reciprocates the plunger with a voice coil motor is employed.

The suction side communication passage 29 of the second embodiment is
The cylinder 22 is slightly formed in the cylinder 22 at right angles to the large diameter hole 25 so as to open at a predetermined position opposite to the intermediate diameter hole 24 of the large diameter hole 25 of the large diameter hole 25. Further, the discharge side communication passage 31 is formed orthogonal to the intermediate diameter hole 24 so as to open at a predetermined position opposite to the large diameter hole 25 of the intermediate diameter hole 24 of the cylinder hole 26. It has a first discharge side passage portion 31a and a second discharge side passage portion 31b formed parallel to the cylinder hole 26.

The cylinder 22 has a suction side communication passage 2
9 is formed adjacent to the suction-side communication passage 29 and has a smaller diameter than the suction-side communication passage 29. A valve chamber 71 having a larger diameter than the portion 70 is formed adjacent to and coaxial with the valve base hole 70, and a smaller diameter than the valve chamber 71 is provided on the opposite side of the valve base hole 70 of the valve chamber 71. The communication hole 72 is formed adjacent to and coaxial with the valve chamber 71.

Further, a valve chamber 74 having a smaller diameter than the second discharge side passage portion 31b is formed adjacent to the cylinder 22 so as to be coaxial with the second discharge side passage portion 31b. On the opposite side to the discharge side passage portion 31b, the valve chamber 74 is provided.
A valve head hole 75 having a smaller diameter is formed adjacent to the valve chamber 74 so as to be coaxial with the valve chamber 74, and has a larger diameter than the valve head hole 75 on the opposite side of the valve chamber 74 from the valve head hole 75. The liquid chamber forming hole 76 is formed adjacent to and coaxial with the valve base hole 75. Here, the communication hole 72 communicates with the liquid chamber forming hole 76 at a position perpendicular to the liquid chamber forming hole 76. Further, the liquid chamber forming hole 76 is opened outside the cylinder 22.

The reservoir communication passage 34 is formed perpendicularly to the large diameter hole 25 so as to open at a position between the cup seal 45 and the cup seal 46 in the large diameter hole 25 of the cylinder hole 26. The reservoir passage portion 34a and the cylinder hole 26
And a second reservoir passage portion 34b formed in parallel with. At an end of the second reservoir passage portion 34b, a reservoir accommodation hole 77 having a diameter larger than that of the second reservoir passage portion 34b is formed, and the reservoir accommodation hole 77 opens outside the cylinder 22. .

The internal communication passage 35 has an opening at one end between the seal member 54 and the seal member 55 in the small-diameter hole 23 of the cylinder hole 26, and has the other end at a predetermined position in the liquid chamber forming hole 76. It is open, and its intermediate portion communicates with the second reservoir communication portion 34b of the reservoir communication passage 34.

The valve chamber 71 is provided with a suction-side check valve 60 that allows the flow of the liquid from the suction-side communication passage 29 toward the liquid chamber forming hole 76 and prevents the flow of the liquid in the opposite direction. . That is, the suction-side check valve 60 includes a valve chamber 71, a spherical valve body 79 movably housed in the valve chamber 71,
Abuts against the valve seat 80 of the valve chamber 71 of the valve chamber 71 to bias the suction-side communication passage 29 in a direction to close the suction-side communication passage 29.
And 1.

The valve chamber 74 is also provided with a discharge-side check valve 61 that allows a flow from the liquid chamber forming hole 76 toward the second discharge-side passage portion 31b and blocks the flow of the liquid in the opposite direction. .
That is, the discharge-side check valve 61 includes a valve chamber 74 and a valve chamber 74.
A spherical valve element 82 movably housed therein, and the valve element 8
2 has a spring member 84 which abuts on the valve seat 83 of the valve chamber 74 side of the valve chamber 74 to bias the second discharge side passage portion 31b in the closing direction.

A substantially bottomed cylindrical outer yoke 88 having a cylindrical portion 86 and a bottom portion 87 is provided on the opening side of the liquid chamber forming hole 76 of the cylinder 12. Liquid chamber forming hole 7
6 and is fixed coaxially. This outer yoke 8
An insertion hole 89 is formed on the bottom 87 of the nozzle 8 so as to be coaxial with the liquid chamber forming hole 76.

A plunger 91 is inserted into the liquid chamber forming hole 76 of the cylinder 22 and the insertion hole 89 of the outer yoke 88 with a gap. A ring-shaped seal member 92 for closing a gap between the plunger 91 and the liquid chamber forming hole 76 is fixed to a tip portion of the plunger 91 on the liquid chamber forming hole 76 side. It is slidable.

Here, the liquid chamber forming hole 76 and the communication hole 72
The liquid chamber whose volume increases and decreases due to the reciprocating motion of the plunger 91, the suction check valve 60, the discharge check valve 61, the seal member 92, and a part of the plunger 91 protruding from the seal member 92. 93 will be defined.

A ring-shaped sealing member 95 for closing a gap with the plunger 91 is fixed to the opening side of the hydraulic pressure forming hole 76.
Is slidable. Here, the internal communication passage 35 is open between the seal member 95 and the seal member 92. The reservoir accommodation hole 77 accommodates a variable-volume in-wheel reservoir 96 that communicates with the internal communication passage 35, whereby the in-wheel reservoir 96 is
Discharge liquid in a chamber located between the cylinder hole 26 and the piston 37 and between the cup seals 45 and 46 is stored, and between the cylinder hole 26 and the piston 37 and between the seal members 54 and 55. Between the liquid chamber forming hole 76 and the plunger 91 and the sealing member 9
It stores leaks to the room located between 2,95
When the hydraulic pressure of the master cylinder 13 is released, the stored liquid is discharged to the master cylinder communication passage 28 via the cup seal 45 of the piston 37.

Inside the outer yoke 88, a cylindrical inner yoke 98 is coaxially fixed to the bottom 87. A plunger 91 is supported inside the inner yoke 98 in a state where misalignment is prevented by a support body 99. A cylindrical magnet for forming a magnetic path is provided on the outer diameter side of the inner yoke 98. 100 is fixed coaxially. Further, a short-circuit ring 101 is fixed to the outer peripheral surface of the magnet 100. This short-circuit ring 101
Is made of a copper plate, and is attached so as to surround the outer periphery of the magnet 100 seamlessly.

The coil 1 is located between the outer diameter side of the short-circuit ring 101 and the inner diameter side of the cylindrical portion 86 of the outer yoke 88.
The coil 102 is fixed to the plunger 91 on the cylinder 22 side of the magnet 100. The magnet 100 includes the short-circuit ring 10
1. A magnetic flux that circulates in the order of the air gap including the coil 102, the outer yoke 88, and the inner yoke 98.
A pressing force proportional to the product of the current of the coil 102 and the magnetic flux density of the air gap is generated.

The short-circuit ring 101 forms a one-turn transformer for the coil 102. When a voltage is applied to the coil 102, a large current flows through the short-circuit ring 101,
The current rise characteristics of the coil 102 are improved. The above plunger 91, outer yoke 88, inner yoke 9
8. Support 99, magnet 100, short-circuit ring 101
The coil 102 constitutes a voice coil motor 103 that drives the plunger 91 by magnetic force.

A stroke sensor 104 is mounted on the outer yoke 88 on the side opposite to the cylinder 22. The stroke sensor 104 detects both end positions of the stroke of the plunger 91, and the control circuit 18
Controls the reversal of the polarity of the current of the coil 102 based on the detection result of the stroke sensor 104,
The coil 102, that is, the plunger 91 reciprocates between both ends of the stroke.

In the pump 16 having such a configuration, the master cylinder communication passage 28 communicates with the master cylinder 13, the wheel cylinder communication passage 33 communicates with the wheel cylinder 15, and the plunger 91 is reciprocated by the voice coil motor 103. The expansion of the volume in the liquid chamber 93 due to the movement of the plunger 91 in one direction (left direction in FIG. 4) causes the suction-side check valve 60 to open while the discharge-side check valve 61 remains closed. Liquid is introduced into liquid chamber 93 from master cylinder 13. Due to the subsequent movement of the plunger 91 in the opposite direction (rightward in FIG. 4), the volume in the liquid chamber 93 is reduced, and the discharge-side check valve 61 is opened while the suction-side check valve 60 is closed. The pressure liquid is discharged from the liquid chamber 93 to the wheel cylinder 15. By repeating such reciprocation, the pressure liquid is forcibly discharged from the master cylinder 13 to the wheel cylinder 15.

The brake device 1 according to the second embodiment described above.
1 will be described. When the brake pedal 12 is depressed, the hydraulic pressure generated in the master cylinder 13 increases, and the hydraulic pressure of the master cylinder 13, which is a predetermined multiple of the area ratio of the piston 37, becomes larger than the hydraulic pressure of the wheel cylinder 15 (ie, When the wheel cylinder pressure corresponding to the master cylinder pressure generated by the input of the brake pedal 12 which is a command for obtaining the required braking force becomes higher than the wheel cylinder pressure at that time), the piston 37
Starts moving toward the one side.

When the piston 37 moves by a predetermined amount toward the one side, the valve seat 43 of the piston 37 comes into contact with the valve element 51 of the stroke sensor 49 to close the pressure reducing valve 52 constituted by these elements, and the master cylinder is closed. 13 and the wheel cylinder 15 are disconnected. Piston 37 is valve element 5
When the switch 1 further moves toward the one side by a predetermined amount, a switch in the sensor main body 50 outputs an ON signal. Then, based on this, the control circuit 18 starts driving the pump 16. That is, a current is applied to the coil 102 in a direction corresponding to the detection result of the stroke sensor 104 to reciprocate the plunger 91. As a result, the brake fluid sucked and discharged from the master cylinder 13 side by the pump 16 is introduced into the wheel cylinder 15 without being released to the master cylinder 13 side, and the braking force increases. After the drive of the pump 16 is started, the piston 37 is moved to the valve body 5.
1 together with the moving end on the one side and stops.

On the other hand, from this state, the brake pedal 12
Is reduced, the hydraulic pressure generated in the master cylinder 13 decreases, and the hydraulic pressure of the master cylinder 13, which is a predetermined multiple of the area ratio of the piston 37, becomes lower than the hydraulic pressure of the wheel cylinder 15 (that is, the required hydraulic pressure). When the wheel cylinder pressure corresponding to the master cylinder pressure generated by the input of the brake pedal 12, which is a command for obtaining the braking force, becomes lower than the wheel cylinder pressure at that time), the piston 37 moves toward the opposite side.

Then, the valve body 51 moves toward the opposite side by the valve body spring together with the piston 37, and the sensor body 5
The switch 0 outputs an OFF signal, and based on this, the control circuit 18 stops the current supply to the coil 102 of the pump 16 and stops the pump 16. Further, when the piston 37 moves toward the opposite side, the piston 37 separates from the valve body 51 to open the pressure reducing valve 52 constituted by these members, and the hydraulic pressure of the wheel cylinder 15 is transmitted through the communication hole 40 to the master cylinder 13. Return to As a result, the brake fluid is released to the master cylinder 13 side, and the braking force decreases.

The brake device 1 according to the second embodiment described above
According to the first embodiment, the same effect as that of the first embodiment can be obtained, and of course, the voice coil motor 10
Since a plunger pump that reciprocates the plunger 91 by magnetic force is used in step 3, the thrust within the stroke can be made constant and high-speed response can be achieved. Therefore, a stable pressure can be immediately generated.

[0063]

As described in detail above, claim 1 of the present invention
According to the brake device described above, when the brake pedal is depressed, the hydraulic pressure generated in the master cylinder increases, and the hydraulic pressure of the master cylinder, which is a predetermined multiple of the area ratio of the piston, becomes greater than the hydraulic pressure of the wheel cylinder. , The piston moves to one side. Then, while the valve is closed to cut off the communication between the master cylinder and the wheel cylinder, the detection means detects the movement of the piston to the one side, so that the control means drives the pump. As a result, the brake fluid discharged from the pump is introduced into the wheel cylinder without being released to the master cylinder side by the valve, and the braking force increases. On the other hand, when the brake pedal is released, the hydraulic pressure generated in the master cylinder decreases, and the hydraulic pressure of the master cylinder, which is a predetermined multiple of the area ratio of the piston, becomes lower than the hydraulic pressure of the wheel cylinder, the piston moves to the opposite side. Go to Then, the valve is opened and the hydraulic pressure of the wheel cylinder is returned to the master cylinder, while the detection means detects the movement of the piston to the opposite side, so that the control means stops the pump. As a result, the brake fluid discharged from the pump is released to the master cylinder side via the valve,
The braking force decreases. Thus, the number of parts can be reduced as compared with the conventional device for controlling the hydraulic pressure obtained by the pump to obtain the braking force, so that piping and wiring can be simplified. In addition, since the pump is driven after the hydraulic pressure on the wheel cylinder side needs to be increased, energy is used more efficiently compared to the conventional method in which high pressure for emergency is constantly generated and the pressure is reduced by the pressure reducing valve. Can be.

According to the brake device of the second aspect of the present invention, since the plunger pump that reciprocates the plunger by the magnetic force by the voice coil motor is used as the pump, the thrust within the stroke can be made constant and the high-speed response can be achieved. It becomes possible. Therefore, a stable pressure can be immediately generated.

According to the brake device of the third aspect of the present invention, the brake pedal is depressed, the hydraulic pressure generated in the master cylinder increases, and the hydraulic pressure of the master cylinder is increased to a predetermined value by the area ratio of the piston. Even if the pressure is greater than the hydraulic pressure of the wheel cylinder, the actuator opens the valve by forcibly moving the piston to the opposite side, allowing the master cylinder and the wheel cylinder to communicate with each other. You can escape to the side. Therefore, the present invention can be applied to a system in which the braking force is forcibly reduced like ABS.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a brake device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing a pressure detection / pressure reduction mechanism of the brake device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing each state with respect to a stroke position of a piston of the brake device according to the first embodiment of the present invention.

FIG. 4 is a side sectional view showing a pressure detection / pressure reduction mechanism of a brake device according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional brake device.

[Explanation of symbols]

 Reference Signs List 11 brake device 12 brake pedal 13 master cylinder 15 wheel cylinder 16 pump 18 control circuit (control means) 37 piston 49 stroke sensor (detection means) 52 pressure reducing valve (valve) 91 plunger 103 voice coil motor

Claims (3)

[Claims] 1. A master cylinder for generating a hydraulic pressure according to an input of a brake pedal, a wheel cylinder for generating a braking force by the introduced hydraulic pressure, a pump for generating a hydraulic pressure to be introduced to the wheel cylinder, The hydraulic pressure of the master cylinder and the hydraulic pressure of the wheel cylinder are received from opposite directions in different areas, respectively, and the hydraulic pressure of the master cylinder, which is a predetermined multiple of the area ratio, exceeds the hydraulic pressure of the wheel cylinder. A piston that moves to one side, and moves to the opposite side when the hydraulic pressure of the master cylinder, which has been multiplied by a predetermined ratio in area ratio, becomes lower than the hydraulic pressure of the wheel cylinder; and the master moves when the piston moves to the one side. While the communication between the cylinder and the wheel cylinder is cut off, the master moves when the piston moves to the opposite side. A valve for communicating the cylinder with the wheel cylinder, detecting means for detecting the position of the piston, and driving the pump in a state where the movement of the piston to the one side is detected by the detecting means, Control means for stopping driving of the pump in a state where the movement of the piston to the opposite side is detected by the detection means,
A brake device comprising: 2. The pump according to claim 1, wherein the pump generates a liquid pressure by reciprocating the plunger, and the plunger is driven by a magnetic force by a voice coil motor. Brake device. 3. The brake device according to claim 1, further comprising an actuator capable of forcibly moving the piston.