JPH02279455A - Hydraulic intensifier for brake fluid pressure - Google Patents

Abstract

PURPOSE:To enhance the degree of freedom for a layout in front of a driver's seat in a vehicle by intensifying a brake fluid at the outside of a brake fluid pressure source, while constituting the brake fluid out of a high pressure fluid supply source so as to put back to a reservoir of this supply source. CONSTITUTION:This hydraulic intensifier 1 has a casing 11 equipped with a port being connected to a master cylinder 3, a port being connected to a high pressure fluid supply source 9 comprising a pump 7 and a port being connected to a wheel cylinder 4. A stepped piston 14 and a boost control piston 15 are fitted in a stepped cylinder 12 and a boost control cylinder 13 formed in this casing 11, respectively. A low pressure chamber 22 to be partitioned off by a large diametral part 19 and a small diametral part 20 of the stepped piston 14 is connected to a reservoir 6 of the high pressure fluid supply source 9, while a small diametral part 25 to be partitioned off by the stepped cylinder 12 and the small diametral part 20 is connected to the low pressure chamber 22 via a pressure regulating valve 27 and to the discharge side of the pump 7 via a high pressure valve 34, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brake fluid pressure increasing device for reducing the pedal force of a front brake.

(Prior Art) Many vehicles these days are equipped with a booster for the purpose of reducing the pedal force exerted by the driver.

Conventional boosters are integrally attached to the master cylinder, and the actuating plunger inside the master cylinder is assisted by negative engine pressure or positive fluid from a separate hydraulic pressure source to increase the pedal force. A force increased in proportion to is supplied to the foil sylinter.

By the way, in order to make it possible to downsize the master cylinder without reducing the boosting effect on the brake system and to increase the degree of freedom in the layout in front of the driver's seat in a vehicle, Japanese Patent Application No. 6:1-37184 was proposed. No. 1 proposes a device that increases the pressure of brake fluid in the middle of the piping connecting the master cylinder and wheel cylinder.

This brake fluid pressure increase device is fitted into a sliding groove in a casing placed in the middle of the piping connecting the master cylinder and wheel cylinder, and is connected to the upstream side (master cylinder @).
The pressure receiving surface of the stepped piston is larger than the downstream side (wheel cylinder side), and a communicating hole is formed to allow the flow of brake fluid.The stepped piston communicates with the stepped piston when it moves downstream. It consists of a control valve that gUTs the hole, and a check valve that connects and shuts off piping that connects a high-pressure liquid supply source such as a pump to the wheel cylinder, and the control valve and check valve are connected according to the movement of the stepped piston. It is linked.

According to this configuration, when the hydraulic pressure on the master cylinder side rises, the stepped piston moves downstream and blocks the communication hole, and then the check valve opens and brake fluid is supplied from the high-pressure fluid supply source. or supplied to the wheel cylinder. In addition, the stepped piston also moves to the flow side due to the brake fluid from the high-pressure fluid supply source, and the check valve closes to stop the supply of brake fluid from the high-pressure fluid supply source. When the fluid pressure is increased, the check valve opens. In this way, the reciprocating movement of the stepped piston causes the supply of brake fluid from the high-pressure fluid supply source to be repeated, and the wheel cylinder is supplied with a hydraulic pressure several times higher than the hydraulic pressure from the master cylinder. Ru.

(Problem to be Solved by the Invention) However, the conventional pressure increasing device has the following problems.

When the pressure in the master cylinder is reduced, the stepped piston moves upstream, and the brake fluid that is being supplied to the wheel cylinder from the high-pressure fluid supply is returned to the master cylinder through the communicating hole in the stepped piston, or If you repeat and rapidly apply the brake fluid, all of the brake fluid will be sent to the wheel cylinder again before it returns to the master cylinder, so the amount of pressure on the brake pedal to obtain the same braking force will change. (When stepping on the brake pedal after turning green, the width of the brake pedal gradually becomes smaller), which caused a problem in that the pedal feel link was extremely deteriorated.

In addition, the brake fluid supplied to the wheel cylinders from the high-pressure fluid supply source is returned to the reservoir of the master cylinder, so it is necessary to communicate or share the reservoir of the high-pressure fluid supply source with the reservoir of the master cylinder. The reservoir installed in the master cylinder has become larger,
There were also problems such as not being able to sufficiently downsize the master cylinder, and requiring long connecting pipes, making assembly into a vehicle difficult.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a brake fluid pressure increasing device that does not worsen pedal feel link.

(Means and effects for solving the problem) The brake fluid pressure increasing device of the present invention has a connection system that supplies hydraulic pressure generated by human operation to a brake device for increasing braking force on a vehicle. , a connection line that increases the hydraulic pressure generated by the high-pressure fluid supply source at a constant rate higher than the hydraulic pressure generated by the human operation and supplies the brake equipment to the brake equipment; It is characterized by having a thread path for returning brake fluid from the high-pressure fluid supply source used to increase the pressure to the high-pressure fluid supply source.

According to this configuration, when the flake operation is released or weakened after the hydraulic pressure generated by the high-pressure fluid supply source is used to increase the hydraulic pressure to the brake equipment, when the flake operation is released or weakened, the brake equipment is The brake fluid from the high-pressure fluid supply source used to increase the pressure of the supplied fluid is returned to the high-pressure fluid supply source from a separate line, so excess brake fluid is returned to the brake fluid pressure source. Things are gone,
If you always perform the same operation, you will get the same braking force.

Further, the brake fluid pressure increasing device of the present invention is a connection system between a brake fluid pressure generation source that generates fluid pressure by human operation and a brake device that receives brake fluid pressure and applies braking force to a vehicle. A high-pressure medium supply source that is slidably inserted into the passageway, receives hydraulic pressure from the brake fluid pressure generation source on the end face on the large diameter side, and generates high hydraulic pressure on the end face on the small diameter side. a stepped piston that receives hydraulic pressure; a high-pressure valve that is provided in a connection path between the high-pressure fluid supply source and the brake device and opens and closes the connection path; and a stepped piston in the connection path and the brake device. and a control valve provided between the control valve and the control valve that opens and closes the connection line.

Opening/closing means for opening the high pressure valve in response to movement of the stepped piston in one direction when the force applied to the large diameter side of the stepped piston becomes greater than the force applied to the small diameter side; and the stepped piston. l3J4r''t'4 means for closing the control valve in response to movement in one direction.

Return means for returning brake fluid supplied from the high pressure fluid supply source to the brake device to the high pressure fluid supply source in response to movement of the stepped piston to the other side.

It is characterized by being composed of.

According to this configuration, initially, the brake fluid from the brake fluid pressure generation source due to the brake operation is sent to the brake equipment without moving the stage 4 piston to provide power to the vehicle. Then, as the pressure of the brake fluid increases, the force applied to the large diameter part of the stepped piston becomes greater than the force applied to the small diameter part, and the stepped piston moves in one direction, opening the high pressure valve by the opening/closing means, and then controlling the piston. The valve is closed and the high hydraulic pressure from the high pressure liquid supply source increases the hydraulic pressure supplied to the brake system. At this time, the stepped piston moves so as to be balanced by the hydraulic pressure from the brake fluid pressure generation source applied to the large diameter part and the hydraulic pressure from the high pressure fluid supply source applied to the small diameter part, and opens and closes the high pressure valve and control valve. For control purposes, hydraulic pressure increased in proportion to the ratio of the pressure-receiving areas of the large-diameter portion and the small-diameter portion of the stepped piston is supplied to the brake device.

In addition, when the brake operation is released or weakened, the force applied to the large diameter side of the stepped piston becomes smaller and moves in the other direction, closing the high pressure valve and opening the control valve, and the force is supplied to the brake device. The brake fluid from the high-pressure fluid supply source used to increase the fluid pressure is returned to the high-pressure fluid supply source by the return means. If you perform this operation, the same braking force will be obtained.

(Example) Next, embodiments of the present invention will be described based on the drawings.

First, a first embodiment of the present invention will be described based on FIG.

The pressure booster 1 is disposed in the middle of a pipe 5 that connects a master cylinder 3, which is a brake fluid pressure generation source that generates fluid pressure in response to depression of a brake pedal 2, and a wheel cylinder 4 of a brake device on each wheel side. The pressure booster 1 includes a pump 7 that pumps the oil in the reservoir 6, and a pump 7.
A high-pressure liquid supply source 9 consisting of an accumulator 8 that stores oil under pressure at a predetermined pressure is connected thereto. The motor 10 that drives the pump 7 is a pressure switch (not shown)! The oil stored in the accumulator 8 is appropriately controlled by $' to maintain it at a predetermined pressure.

Inside the goo sink 11 of the pressure booster l, there is a stepped cylinder 12.
and a pressure increase control cylinder 13 are arranged side by side with their axial directions aligned, and a stepped piston 14 and a pressure increase control piston 15 are slidably fitted into each cylinder 12,13. Three large-diameter chambers 17 are connected to the large-diameter cylinder 16 side of the stepped cylinder 12, and the large-diameter chambers 17 are communicated with the master cylinder 3 through a connecting pipe 5. Large diameter chamber 1
7 and the pressure increase control cylinder 13 communicate with each other through a passage 18, and further, the pressure increase control cylinder I3 communicates with the wheel cylinder 4 through a connecting pipe 5, so that the master cylinder 3 and the large diameter chamber 17, It communicates with the wheel cylinder 4 via the passage 18 and the pressure increase control cylinder 13.

The stepped piston 14 has the large diameter portion 1g side connected to the stepped cylinder 12.
The small diameter cylinder 2 is connected to the large diameter cylinder 16 on the small diameter cylinder 20 side.
1, and a low pressure chamber 22 defined by the stepped cylinder 12, a large diameter portion 19, and a small diameter portion 20 is provided with a stepped piston 14 that engages with the large diameter portion 19 and is in sliding contact with the large diameter portion 19 and the small diameter portion 20. A spring 23 that presses against the diameter chamber 17 is also provided. Further, the low pressure chamber 22 is communicated with the reservoir 6 of the high pressure liquid supply source 9 through a connecting pipe line 24 .

A small diameter chamber 25 defined by the stepped cylinder 12 and the small diameter portion 20 of the stepped piston 14 communicates with the low pressure chamber 22 through a return passage 26 formed in the stepped piston 14. A spherical pressure regulating valve 27 and a valve seat 28 that seats the pressure regulating valve 27 and blocks communication are provided therein. The pressure regulating valve 27 is urged toward the valve seat 28 by the spring 29, but when the stepped piston 14 is located at the end on the large diameter chamber 17 side (the state shown in FIG. 1), It is separated from the valve seat 28 by the valve stem 30 . Note that 31 is a valve stem stopper that supports the valve stem 30.

A high pressure chamber 33 is formed in the casing 11 and communicates with the small diameter chamber 25 via a passage 32, and a spherical high pressure valve 34 is provided in the high pressure chamber 33. Also, aisle 3
A valve seat 35 on which a high pressure valve 34 is seated and blocks communication is formed at the end of the valve 2, and the high pressure valve 34 is urged toward the valve seat 35 by a spring 36. A protrusion 37 that can be inserted into the passage 32 is formed on the end face of the small diameter portion 20 of the first stage piston 14 as an opening/closing means, and the first stage piston 14 is moved toward the small diameter chamber 25 side (toward the left side in the figure). movement), the protrusion 37 presses the high pressure valve 34 and the valve seat 3
It can be separated from 5. Note that the protrusion 3 of this opening/closing means
7 may be provided in the high pressure valve 34 instead of the stepped piston 14.

The high pressure chamber 3 communicates with the high pressure liquid supply source 9 through a connecting pipe 38, and oil liquid at a predetermined pressure is always introduced therein.

The pressure increase control piston 15 is connected to the pressure increase control cylinder 13.
The inside is defined by a front chamber 39 of the passage 18 which communicates the large diameter chamber 17 and the pressure increase control cylinder 13, and a rear chamber 40 on the opposite side, and the pressure increase control piston 15 is connected to the pressure increase control cylinder 13. 13 is biased toward the rear chamber 40 by a spring 41 disposed inside the chamber 13. The small diameter chamber 2!5 of the stepped cylinder 12 and the rear chamber 40 of the pressure increase control cylinder 13 are communicated through a connecting pipe 42.

A valve seat 4 is provided at the end of the passage 18 on the pressure increase control cylinder 13 side.
A main valve 44 is provided in the pressure increase control cylinder 13, which is a control valve that seats on this valve seat 43 and blocks communication between the large diameter chamber 17 and the wheel cylinder 4. The main valve 44 is movably supported by a guide 45,
It is biased by a spring 46 in the direction of seating on the valve seat 43. The main valve 44 also includes a pressure increase control piston 1.
A rod 48 extending to the 5 side and inserted into a hole 47 formed in the pressure increase control piston 15 is coupled thereto. When the pressure increase control piston 15 is located at the rear chamber 40 side end of the pressure increase control cylinder 13, the enlarged diameter portion 49 provided at the end of the rod 48 or the end of the pressure increase control piston 15 The main valve 44 is separated from the valve seat 43 and the large diameter chamber 17 and the wheel cylinder 4 are communicated with each other.

In order to prevent oil leakage between the large diameter chamber 17 and the low pressure chamber 22, the large diameter portion 19 of the stepped piston 14 is located outside the large diameter chamber 19 and the low pressure chamber 22.
In order to prevent leakage of oil between the small diameter chamber 25 and the small diameter portion 20 of the stepped piston 14, the pressure increase control cylinder 13
In order to prevent leakage of oil between the front chamber 39 and the rear chamber 40, a seal member 51 made of an O-ring or the like is provided on the outer periphery of the pressure increase control piston 15, respectively.

The operation of the pressure booster having the above configuration will be explained.

first. Before pressing brake pedal 2.

The state is as shown in FIG.

When the brake pedal 2 is depressed, brake fluid pressure-fed from the master cylinder 3 is supplied to the wheel cylinder 4 via the connection pipe 5, the large diameter chamber I7, and the pressure increase control cylinder 13. As the pressure of the brake fluid from the master cylinder 3 increases, large fluid pressure is applied to the end surface of the large diameter portion 19, and the stepped piston 14 begins to move toward the small diameter chamber 25 against the biasing force of the spring 23. Accordingly, the pressure yJR regulating valve 27 is seated on the valve seat 28, and the return passage 26 that communicates the small diameter chamber 25 and the low pressure chamber 22 is cut off. The movement of the stepped piston H at this time is such that the product of the hydraulic pressure in the large diameter chamber 17 and the pressure receiving area of the large diameter part 19 of the stepped piston 14 is the hydraulic pressure in the small diameter chamber 25 and the pressure receiving area of the small diameter part 20. This occurs when the product becomes larger than the product of the elastic force of the spring 23 and the elastic force of the spring 23.

Further, as the stepped piston 14 moves, the protrusion 37 on the end surface of the small diameter portion 20 presses the high pressure valve 34 and separates it from the valve seat 35, so that high pressure oil is introduced from the high pressure chamber 33 into the small diameter chamber 25. . Then, oil is supplied from the small diameter chamber 25 to the rear chamber 40 of the pressure increase control cylinder 13 via the connecting pipe 42, and the pressure increase control piston 15 moves and the main valve 44 is moved to the valve seat 43.
The hydraulic pressure on the wheel cylinder 4 side is increased by the movement of the pressure increase control piston 15. In addition, small diameter room 2
The hydraulic pressure inside the stepped piston 14 also rose and the stepped piston 14 was pushed back, causing the high pressure valve 34 to sit on the valve seat 35 and close the passage 32, thereby temporarily maintaining the force balance of the stepped piston 14. It will be done. The balance relationship of the forces applied to the stepped piston 14 at this time is Pw'A''PA-a+
Fo = (1) P, hydraulic pressure PA applied to the large diameter portion 19 side of the two-stage piston 14 = hydraulic pressure A applied to the small diameter portion 20 side of the stepped piston 14; Pressure-receiving area a: Pressure-receiving area Fo on the small diameter portion 20 side of the two-stage piston 4 = force i of the spring 23.

In this state, when the brake pedal 2 is further depressed and the hydraulic pressure on the master cylinder 3 side increases, the high pressure valve 34 is separated from the valve seat 35 again and high pressure oil is introduced into the small diameter chamber 25. In this way, as the stepped piston 14 moves, the high pressure valve 34 is repeatedly moved away from and seated on the valve seat 35, thereby supplying the rear chamber 40 of the pressure increase control cylinder 13 with oil with increased pressure.

The balance relationship of the force applied to the pressure increase control piston 15 at this time is Pw-B + F, = PA-B - (2) P
w: Fluid pressure on the wheel cylinder 4 side B: Pressure-receiving area (both sides) of the pressure increase control piston 15 F, elastic force of the spring 41, PA is calculated from equation (1) as follows: PA= 1/a (Pw” A −F ,)
It is represented by "" (:l), and when this is substituted into equation (2), P, = A/a-P.

((Fo/a)” (F+/B))=・(
4) is obtained.

As can be seen from equation (4), the rate of increase in the hydraulic pressure on the wheel cylinder 4 side relative to the hydraulic pressure from the master cylinder 3 is the same rate until the stepped piston 14 starts moving; After the start of movement, the pressure will be increased at a ratio of A/a (as shown in Figure 3).

Further, when the brake pedal 2 is released and the hydraulic pressure on the master cylinder 3 side decreases, the stepped piston 14 moves toward the large diameter chamber 17 because the hydraulic pressure in the large diameter chamber 17 decreases. The high pressure valve 34 is seated on the valve seat 35 to block the passage 32 communicating between the high pressure chamber 33 and the small diameter chamber 25, and furthermore, the pressure regulating valve 27 is separated from the seat surface 28 by the valve stem 30,
The small diameter chamber 25 and the reservoir 6 are communicated with each other. This results in
The oil in the rear chamber 40 of the pressure increase control cylinder 13 is transferred to the reservoir 6.
The pressure increase control piston 15 is moved toward the rear chamber 40 by the spring 41, and the main valve 44 is pushed out from the valve seat 43, so that the master cylinder 3 and the wheel cylinder 4 communicate with each other.

Next, a second embodiment will be described. Note that the same members as those in the first embodiment are designated by the same reference numerals, and corresponding members are designated with an "a" in addition to the reference numerals in the first embodiment, and detailed description thereof will be omitted.

Inside the casing lla, a stepped cylinder 12a on which a single-stage piston 14a slides and a pressure increase control cylinder 13a on which a pressure increase control piston 15a slides are arranged in parallel axial directions. It is formed in the stepped piston 14a.

A return passage 26 that communicates the low pressure chamber 22a and the small diameter chamber 25a.
a is open at the axial position of the small diameter portion 20a. In addition, the high pressure valve 34a provided in the high pressure chamber 33a has a rotating mechanism that contacts the opening of the return passage 25a formed in the stepped piston 14a and blocks the return passage 26a. As the attached piston 14a moves, the high pressure valve 34a
A protrusion 52 is integrally formed to separate the valve from the valve seat 35a.

A check valve 53 is interposed between the large diameter chamber 17a that communicates with the master cylinder 3 and the connecting pipe 5 of the wheel cylinder 4. It consists of a spring 56 that urges a valve seat 55 formed on the 19 side. Moreover, the large diameter portion 1 of the stepped piston 14a
A protrusion 57 is provided at the end of the check valve 53 so that the valve body 54 of the check valve 53 can be separated from the valve seat 55 against the biasing force of a spring 56. Note that this protrusion 57 may be provided on the valve body 54 of the check valve 53 instead of the stepped piston 14a.

The rear chamber 40a of the pressure increase control cylinder 13a communicates with the small diameter chamber 25a through a passage 58, and the front chamber 39a communicates with the downstream side of the check valve 53 through a passage 59.

The operation of the pressure booster 1a of the second embodiment having the above configuration will be explained.

First, before stepping on brake pedal 2.

The state is as shown in FIG.

When the brake pedal 2 is depressed, brake fluid pumped from the master cylinder 3 is supplied to the wheel cylinder 4 via the connecting pipe 5, the large diameter chamber 17a, and the check valve 53. As the hydraulic pressure of the brake fluid from the master cylinder 3 increases, pressure is applied to the end face of the large diameter portion 19a, and the stepped piston 14a resists the biasing force of the spring 23a toward the small diameter portion 20a of the stepped cylinder 12a. As the wheel cylinder begins to move, the valve body 54 of the check valve 53 first seats on the valve seat 55, and communication between the master cylinder 3 and the wheel cylinder 4 is cut off. Subsequently, the protrusion 52 of the high pressure valve 34a contacts the return passage 26a that communicates the small diameter chamber 25 and the low pressure chamber 22a, thereby blocking the communication.

Further, as the stepped piston 14a moves, the stepped piston 14a presses the high pressure valve 34a and separates it from the valve seat 35a, thereby introducing high pressure oil from the high pressure chamber 33a into the small diameter chamber 25a. and.

Oil is supplied from the small diameter chamber 25a to the rear chamber 40a of the pressure increasing i'IJ control cylinder through the passage 58, and the pressure increasing control piston 15a moves to increase the hydraulic pressure on the wheel cylinder 4 side. Further, the hydraulic pressure in the small diameter chamber 25a also rises and pushes back the stepped piston 14a, and accordingly, the high pressure valve 34a seats on the valve seat 35a and blocks the passage 32a, temporarily causing the stepped piston +4a The balance of power is maintained.

In this state, when the brake pedal 2 is further depressed and the hydraulic pressure on the master cylinder 3 side increases, the high pressure valve 34a
is separated from the valve seat 35a, and high pressure oil is introduced into the small diameter chamber 25a. In this way, by the movement of the stepped piston eye a, the detached dust is returned to the high pressure valve 34a or the valve seat 35a, and oil liquid with increased pressure is supplied to the rear chamber 40a of the pressure increase control cylinder 13a. .

At this time, the ratio of increase in the hydraulic pressure on the wheel cylinder 4 side to the hydraulic pressure from the master cylinder 3 is the same as in the first embodiment.

Also, if the hydraulic pressure on the master cylinder 3 side decreases,
Because the hydraulic pressure in the large diameter chamber 17a decreases, the stepped piston 14
a moves to the large diameter chamber 17a side, and the high pressure valve 3 and β move to the valve seat 35.
a, the passage 32a that communicates between the high pressure chamber 33a and the small diameter chamber 25a is closed, and the return passage 26a of the stepped piston 14a is opened, and the small diameter chamber 25a and the reservoir 6 are opened.
It will be communicated. As a result, the pressure increase control cylinder 13a
The oil in the rear chamber 40a is returned to the reservoir 6, and the pressure increase control piston 15a is moved to the rear chambers j and oa by the spring 41a.
Move to the side. Then, the protrusion 57 of the stepped piston 14a
As a result, the valve body 54 of the check valve 53 is separated from the valve seat 55, and the master cylinder 3 and the wheel cylinder 4 are communicated with each other.

Note that in this second embodiment, the pressure increase control piston 15a
Since the valve body 54 of the check valve 53 is seated on the valve seat 55 before the check valve 53 moves, and the communication between the master cylinder 3 and the wheel cylinder 4 is closed, the wheel cylinder is closed due to the movement of the pressure increase control piston 15a during pressure increase operation. Since the brake fluid supplied to the cylinder 4 is prevented from flowing back to the master cylinder 3 side, there is an advantage that a good pedal feeling can be obtained.

Furthermore, in the second embodiment, the stepped piston 14a is
It is formed from two members, a member on the large diameter portion 19a side and a member on the small diameter portion 20a side.By forming from the two members in this way, a stepped piston that is easy to manufacture and has high dimensional accuracy is provided. can do.

(Effects of the Invention) As described in detail above, the present invention increases the pressure of brake fluid with a device external to the brake fluid pressure generation source, such as a master cylinder, so that it is possible to increase the brake fluid pressure generation source itself. In addition, the brake system can be operated with a sufficiently large boost without any pressure increase, and the brake fluid supplied from the high-pressure fluid supply source is not returned to the brake fluid pressure generation source to increase the pressure, but the brake fluid is supplied with high-pressure fluid. Since the brake force is returned to the original reservoir, the same brake force is always generated even when the same brake pedal is depressed, resulting in a good pedal feel. As a result, the effect of expanding the degree of freedom of the driver in front of the driver's seat in the vehicle is achieved without deteriorating the pedal feel.

Furthermore, since the reservoir for the high-pressure fluid supply source can be provided separately from the reservoir provided for the brake fluid pressure generation source, the long piping that connects the high-pressure fluid supply source from the brake fluid pressure generation source reservoir as in the past is eliminated. Furthermore, it is also possible to downsize the reservoir of the brake fluid pressure generation source.

[Brief explanation of drawings]

1 is a schematic diagram of a first embodiment of a brake fluid pressure increase device of the present invention; FIG. 2 is a schematic diagram of a second embodiment of a brake fluid pressure increase device of the present invention; The figure is a diagram showing the relationship between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure when the brake fluid pressure increase device of the present invention is used. ■...Pressure booster 3...Master cylinder (brake fluid pressure generation source) 4...
・Wheel cylinder (brake device) 9... High pressure fluid supply device 12... Stepped cylinder 13... Pressure increase control cylinder 14... Stepped piston 15... Pressure increase control piston 17... Large Diameter chamber 25...Narrow diameter chamber 1
Figure 34... High pressure valve 39... Front chamber 44... Main valve (control valve) 37... Protrusion (opening/closing means) 40... Rear chamber

Claims (8)

[Claims] (1) A connection line that supplies hydraulic pressure generated by the human operation to a brake device for applying braking force to the vehicle, and a hydraulic pressure generated by the high-pressure fluid supply source to utilize the hydraulic pressure generated by the human operation. a connection line that supplies the brake device with a hydraulic pressure that is increased at a constant rate from the hydraulic pressure generated by the brake device; and the high-pressure fluid supply that is used to increase the hydraulic pressure that is supplied to the brake device. A brake fluid pressure increasing device comprising: a line for returning brake fluid from a source to the high pressure fluid supply source. (2) Sliding freely within the first connection path that connects the brake fluid pressure generation source where fluid pressure is generated by human operation and the brake device that receives brake fluid pressure and applies braking force to the vehicle. The stepper is fitted into the brake fluid pressure source and receives hydraulic pressure from the brake fluid pressure generation source on the end face of the large diameter part, and receives hydraulic pressure from the high pressure fluid supply source that generates high hydraulic pressure on the end face of the small diameter part. Provided in a second connection line connecting the piston, the high-pressure fluid supply source, and the brake device, when the force applied to the large diameter side of the stepped piston becomes greater than the force applied to the small diameter side. a high-pressure valve that opens the second connection line in response to movement of the stepped piston in one direction; and a high pressure valve provided between the stepped piston and the brake device in the first connection line, a control valve that closes the first connection line in response to movement of the stepped piston in one direction, and a brake fluid of the high-pressure fluid supply source used to increase the fluid pressure supplied to the brake device. , a return means for returning the stepped piston to the high-pressure fluid supply source in accordance with the movement of the stepped piston to the other side; and a brake fluid pressure increasing device. (3) A brake fluid pressure increase device installed in the connection piping between the master cylinder and the wheel cylinder to increase the fluid pressure from the master cylinder and supply it to the wheel cylinder, which is used for stepped cylinders. A large-diameter chamber is provided on the large-diameter side of a slidable stepped piston, and a small-diameter chamber is provided on the small-diameter side, and the master cylinder and the wheel cylinder are communicated via the large-diameter chamber, and the small-diameter chamber and a high-pressure liquid supply source that generates high-pressure liquid pressure are connected via a high-pressure valve, and when the force applied to the large diameter side of the stepped piston is greater than the force applied to the small diameter side, the stepped piston An opening/closing means is provided to open the high pressure valve in response to movement of the piston in one direction, and the pressure increase control piston divides the inside of the pressure increase control cylinder into a front chamber communicating with the wheel cylinder and a rear chamber communicating with the small diameter chamber. a control valve that closes communication between the large diameter chamber and the wheel cylinder in response to movement of the stepped piston in one direction, and opens communication in response to movement of the stepped piston in the other direction; A brake fluid pressure system characterized in that a return means is provided for returning the brake fluid supplied to the rear chamber of the pressure increase control cylinder to the high pressure fluid supply source in accordance with the movement of the stepped piston in the other direction. pressure booster. (4) Claim (3) wherein the control valve is a main valve that is provided on the pressure increase control piston and opens and closes a passage communicating between the large diameter chamber and the wheel cylinder according to the movement of the pressure increase control piston.
The brake fluid pressure increase device described in . (5) A claim in which the control valve comprises a check valve connected to a large diameter chamber, and a protrusion provided on either the stepped piston or the valve body of the check valve to open and close the check valve. The brake fluid pressure increase device according to (3). (6) The brake fluid pressure increasing device according to claim 3, wherein the opening/closing means for opening and closing the high pressure valve comprises a stepped piston or a protrusion provided on the high pressure valve. (7) A return means is formed in the stepped piston, and includes a return passage that communicates the small diameter chamber with a reservoir provided in the high pressure liquid supply source, and a force applied to the large diameter side of the stepped piston through the return passage. The brake fluid according to claim (3), (4), (5) or (6), further comprising a pressure regulating valve that opens in response to movement of the stepped piston when the force applied to the small diameter portion becomes smaller than the force applied to the small diameter portion. Pressure intensifier. (8) Claims (2), (3), (4), (
5), the brake fluid pressure increasing device according to (6) or (7).