JPH0583427B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic booster for assisting the operation of a brake or clutch master cylinder of a vehicle or the like.

Conventionally, this kind of device has a main body formed with a cylinder hole, a piston slidably inserted into the cylinder hole, and a pressure source formed on the side of the piston and connected to a pressure source that supplies pressurized liquid. an input room;
A pressure chamber formed at the rear of the piston, a recess provided at the rear side of the piston in communication with the input chamber and the pressure chamber, a valve device provided in the recess, and the valve device operable. Equipped with an input shaft arranged in
The valve device includes a movable valve body slidably inserted into the recess, a valve seat formed on a rear side wall of the recess opposite to the movable valve body, and a movable valve seat such that the movable valve is seated on the valve seat. It is known that the movable valve body has a valve spring that biases the valve body backward, the front side of the valve seat is connected to the input chamber, and the rear side is connected to the pressure chamber, and further, the movable valve body is made of steel. It is known as a ball.

However, in such conventional valves, the movable valve body receives the pressure in the input chamber over a fairly large area, which increases the operating force required to open the valve at the start of operation, increases the operating resistance, and reduces the speed of operation or There is a problem that efficiency decreases.

The present invention was made in view of the above problems, and an object of the present invention is to provide a hydraulic booster with improved operating efficiency. According to the present invention, this object includes a main body having a cylinder hole, a piston that is slidably inserted into the cylinder hole and is biased rearward when not in operation.
an accumulator pressure chamber formed on the side of the piston and connected to a pressure source for supplying pressurized fluid; a pressure chamber formed at the rear of the piston; It includes a recess provided in the rear side, a valve device provided in the recess, and an input shaft on which the valve device is operable, and the valve device is inserted into the recess and aligned with the axis of the piston. A movable valve body that is movable in a direction, a valve seat formed on a rear side wall of the recess opposite to the movable valve body, and a valve spring that biases the movable valve body rearward so as to be seated on the valve seat. The front side of the valve seat is connected to the accumulator pressure chamber, and the rear side is connected to the pressure chamber, and when the input shaft is not in operation, the pressure chamber is connected to a reservoir, and the input shaft is connected to the front side. In the hydraulic booster configured to move the movable valve body away from the valve seat to introduce pressure fluid into the pressure chamber and move the piston forward during operation, the movable valve body includes: , a columnar portion extending toward the front side of the piston and fitted into the recess through a sealing member; a reduced diameter portion extending from the columnar portion toward the rear end side and having a smaller diameter than the columnar portion; and the columnar portion. and a stepped portion located between the reduced diameter portion and the valve seat, and the valve seat is sealed by the seating area of the stepped portion with respect to the valve seat and the sealing member of the columnar portion. This is achieved by a hydraulic booster formed by bulging the recess radially inward so that the areas are equal to each other.

In the above configuration, the difference between the seating area of the stepped portion and the sealing area by the sealing member becomes almost zero, and the force exerted on the movable valve body by the hydraulic pressure in the input chamber becomes almost zero, eventually causing the movable valve body to close to the valve seat. The pressing force is almost solely the spring force of the valve spring, and the force that causes the input shaft to move the movable valve body away from the valve seat is extremely small, making it possible to greatly improve the speed and efficiency of operation.

EMBODIMENT OF THE INVENTION Hereinafter, a master cylinder with a hydraulic booster for brakes according to an embodiment of the present invention will be described with reference to the drawings.

In the figure, the master cylinder with a hydraulic booster of this embodiment is indicated as 1 as a whole, and a master cylinder part 3 is located on the left side of the cylinder body 2.
A booster unit 4 is provided on the right side. A stepped hole 5 is formed in the cylinder body 2, the front end is a closed end, and the rear end opening is closed by a lid 6. The lid body 6 is fixed to the cylinder body 2 by a plurality of bolts 16 with a seal ring 7 interposed therebetween, and the entire master cylinder 1 with a hydraulic booster is fixed to a toe board (not shown) by the bolts 16.

A shaft-shaped input member 9 having a cup seal 11 attached to its rear end is slidably fitted into the center through hole 8 of the lid 6, and is biased rearward by a spring 10. (Note that in this specification, the front means the left side in the figure, and the rear means the right side in the figure.) Also, the recess 15 formed at the rear end of the input member 9 is not shown in the figure. The tip of the rod portion 13 of the connecting member 12 connected to the brake pedal is received and prevented from coming off by a rubber member 15a. A boot 14 is provided between the rod portion 13 and the lid body 6.
is fixed to prevent dust.

The stepped hole 5 of the cylinder body 2 consists of a large diameter hole 17 and a small diameter hole 18, and a first piston 19 is slidably fitted into the large diameter hole 17 and the small diameter hole 18. , a second piston 20 is provided in the small diameter hole portion 18.
are slidably fitted. The first piston 19 has a first large diameter part 21, a second large diameter part 22 (same diameter as the first large diameter part 21), and a small diameter part 23 at the rear end, middle part, and front end, respectively, and has a cup seal. 24,
25 and 26 are installed. Thus, an auxiliary pressure chamber 27 is formed between the second large diameter section 22 and the small diameter section 23, and an accumulator pressure chamber 28 is formed between the second large diameter section 22 and the first large diameter section 21. Ru. Further, a boosting pressure chamber 29 is formed between the first large diameter portion 21 and the lid 6. These auxiliary pressure chambers 27,
Of the accumulator pressure chamber 28 and booster pressure chamber 29, only the auxiliary pressure chamber 27 belongs to the master cylinder section 3, and the front half of the first piston 19 that defines this pressure chamber 27 is the master cylinder. Although it belongs to part 3, hereinafter referred to as this master cylinder part 3.
The details will be explained below. A bolt 31 is screwed onto the front end of the first piston 19.
A substantially spring-shaped spring receiver 33 is engaged with the head portion of the spring, and a ring-shaped spring receiver 32 is fitted with the shaft portion of the spring receiver 33. A spring 34 is tensioned in a compressed state between these spring receivers 32 and 33. The spring receiver 33 is located at the rear end of the second piston 20, and the spring receiver 32 is located at the rear end of the first piston 1.
It is pressed against the front end of 9. Also, the first piston 1
Small diameter portion 23 as a head formed at the front end of 9
The above-mentioned cup seal 26 is mounted in contact with this, and the rear end large diameter portion 36 of the second piston 20 is mounted on the other hand.
Since the cup seal 38 is attached to the first piston 19 and the second piston 20, the first
A hydraulic pressure generating chamber 40 is formed. Note that a through hole 30 is formed in the small diameter portion 23 of the first piston 19 located behind the cup seal 26, and a through hole 30 is formed in the small diameter portion 23 of the first piston 19.
When the hydraulic pressure in the first hydraulic pressure generating chamber 40 is higher than that in the first hydraulic pressure generating chamber 40, the hydraulic fluid passes through the through hole 30, opens the lip of the cup seal 26, and flows into the first hydraulic pressure generating chamber 40. It is configured as follows. 1st
No hydraulic fluid flows from the hydraulic pressure generating chamber 40 into the auxiliary pressure chamber 27 through the through hole 30. That is, the lip portion of the cup seal 26 and the portion of the small diameter portion 23 of the first piston 19 where the through hole 30 is formed constitute a check valve.

A cup seal 37 is also attached to the front end large diameter portion 35 of the second piston 20, so that the front end large diameter portion 35
A pressureless chamber 39 is formed between the piston 20 and the rear end large diameter portion 36, and a second hydraulic pressure generating chamber 41 is formed between the piston 20 and the bottom wall of the cylinder body 2.
The second piston 20 is biased to the right by a return spring 47 stretched between a spring receiver 48 fitted to the front end of the second piston 20 and the bottom wall of the cylinder body 2 . Note that the cylinder body 2 includes a first
An output port is formed in communication with each of the hydraulic pressure generating chamber 40 and the second hydraulic pressure generating chamber 41, and these are connected to pipe lines 44, 43, and first electromagnetic valves 110, 11, which will be described later.
2. Rear wheel 46 via second solenoid valves 111, 113
The wheel cylinder 46a of the front wheel 45 is connected to the wheel cylinder 45a of the front wheel 45. In addition, the front wheel 45,
Although only one rear wheel 46 is shown in the figure, it is assumed that the other front wheel and rear wheel have a similar configuration.

A check valve similar to that described above is also provided between the second hydraulic pressure generating chamber 41 and the pressureless chamber 39. That is, the second piston 20 is located behind the cup seal 37.
A through hole 42 is formed in the front large diameter portion 35 of the cup seal 37 , and when the hydraulic pressure in the no-pressure chamber 39 is higher than the hydraulic pressure in the second hydraulic pressure generating chamber 41 , the hydraulic fluid passes through this through hole 42 and closes the cup seal 37 . The liquid pressure is configured to flow into the second hydraulic pressure generating chamber 41 by opening the lip portion of the hydraulic pressure generating chamber 41 . No hydraulic fluid flows from the second hydraulic pressure generating chamber 41 into the pressureless chamber 39 through the through hole 42 . That is, the lip portion of the cup seal 37 and the portion of the large front portion 35 of the second piston 20 where the through hole 42 is formed constitute a check valve.

A boss portion 51 is formed on the upper wall of the front end portion of the cylinder body 2, and its fluid connection hole 52 communicates with the second fluid pressure generating chamber 41 through the return hole 50 when the brake shown in the figure is not in operation. and is constantly in communication with the pressureless chamber 39 via the supply hole 49. Further, a cylindrical portion 55 of a reservoir joint 54 is press-fitted into the liquid connection hole 52 via a grommet seal 53, and its flange portion is interposed between the fixing member 58 and the grommet seal 53. The reservoir joint 54 is fixed to the cylinder body 2 by fixing the downward protrusion 58a to the lateral protrusion 51a of the boss portion 52 with a screw 59. A rubber tube is connected to the rubber tube connection portion 56 of the reservoir joint 54 as shown by the dotted line, and communicates with the reservoir shown at a point 57.

A boss portion 62 higher than the above-mentioned boss portion 51 is formed on the upper wall of the intermediate portion of the cylinder body 2, and a multiple valve device 64 whose details are shown in FIG. 2 is disposed below the liquid connection hole 63. This lower bottom hole 65
is in communication with the first hydraulic pressure generating chamber 40 via the return hole 61, and is always in communication with the auxiliary pressure chamber 27 via the supply hole 60. In addition, a reservoir joint 6 is connected to the upper part of the liquid connection hole 63 via a grommet seal 66.
The cylindrical portion 68 of No. 7 is press-fitted, and its flange portion is interposed between the fixing member 58 and the grommet seal 66, and the downward protruding portion 58 of the fixing member 58 is
a to the lateral protrusion 51a of the boss portion 52 with the screw 59.
By fixing the reservoir joint 67 to the cylinder body 2, the reservoir joint 67 is fixed to the cylinder body 2. That is, the fixing member 58 is a common fixing means for both reservoir joints 54 and 67. Rubber pipe connection part 6 of reservoir joint 67
A rubber tube is connected to 9 as shown by the dotted line and communicates with the reservoir shown at point 57. Although a bore 70 is shown for reservoir joint 67, the other reservoir joint 54 has a similar shape and includes a similar bore. Further, a plurality of protrusions 71 are formed on the flange portions of the reservoir joints 54 and 67 as shown in the figure for one reservoir joint 67, and by engaging with a plurality of recesses of the fixing member 58, both reservoir joints 54, 67 is firmly fixed to the cylinder body 2.

Next, details of the multiple valve device 64 disposed in the lower part of the boss portion 62 will be explained with reference to FIG. 2.

This valve device 64 includes a first valve portion 72 and a second valve portion 73.
These valve parts 72 and 73 are comprised of a valve body 74.
are common. A spring receiver 78 is provided on the valve body 74.
The entire valve device 64 is fluid-tightly secured to the boss portion 62 by a stop ring 82 which is fitted to the outer edge and engages with the spring receiver 78, and a seal ring 80 which is in pressure contact with the lower tapered portion 64a of the valve body 74. Liquid connection hole 6
Fixed to 3. Spring receiver 78 and valve body 7
A first valve chamber 79 is formed between the valve body 4 and the valve body 74, and within this valve chamber 79, a ball valve 76 is seated on a valve seat 74c formed in the valve body 74. Ball valve 76 is spring receiver 78
A leaf spring 77 stretched between the valve body 74 and the valve body 74 biases the valve seat 74c toward the valve seat 74c. Also, the valve body 7
A first through hole 74a is formed in the center of the valve body 74, and this through hole 74a is connected to a second through hole 74a formed below the valve body 74.
It communicates with a bottom hole 65 serving as a valve chamber, and in the normal illustrated state, a first valve chamber 79 is connected by a ball valve 76.
Communication with has been cut off.

A plurality of second through holes 74b are further formed around the first through hole 74a in the valve body 74, and these communicate with the first valve chamber 79, and normally the valve body 74
Communication with the bottom hole 65 serving as the second valve chamber is blocked by a rubber valve member 81 fixed to the lower end of the valve chamber. As described above, the first valve portion 72 is connected to the ball valve 7.
6, the valve body 74, the valve seat 74c, and the leaf spring 77;

The first valve chamber 79 is a central opening 78a of the spring receiver 78.
The bottom hole portion 65 serving as the second valve chamber communicates with the inside of the cylinder hole of the cylinder body 2 through the return hole 61 and the supply hole 60 as described above. ing. Further, a throttle groove 74d is formed in the lower end peripheral portion of the valve body 74,
The first valve chamber 79 and the bottom hole portion 65 serving as the second valve chamber are always in communication via the throttle groove 74d and the second through hole 74b.

When the pressure in the bottom hole 65 serving as the second valve chamber becomes higher than the pressure in the first valve chamber 79 by a predetermined value or more, the first valve chamber 7
2 opens, and the bottom hole 65 as the second valve chamber and the first
It is in free communication with the valve chamber 79. This valve opening pressure is determined by the strength of the leaf spring 77, the seating area of the ball valve 76 with respect to the valve seat 74, etc. Further, the opening pressure of the second valve part 73 is sufficiently small, and when the pressure in the bottom hole part 65 as the second valve chamber is lower than the pressure in the first valve chamber 79 communicating with the reservoir by a predetermined value or more, that is, the second valve part 73 is opened. The valve is configured to open when the bottom hole 65 as a chamber becomes negative pressure.

Next, details of the booster section 4 will be explained with reference to FIG. 1 again.

The first piston 19 is also one of the main components of the booster section 4, and is located above the above-mentioned accumulator pressure chamber 28 formed on the rear and side circumferential portions, and has a boss portion in the cylinder body 2. 83 is formed, and a connecting member 84 is screwed onto this. Boss part 8
A check valve consisting of a ball valve 85 and a valve spring 86 is disposed inside 3, and the forward direction is from the upper side to the lower side, and the side of the pipe line 87 is connected to the connecting member 84 through the through hole 83a. can communicate with the accumulator pressure chamber 28. An accumulator 88 is connected to the conduit 87, and a discharge port of a hydraulic pump 91 is connected via a conduit 89 and a check valve 90. The check valve 90 is connected to the pipe line 87 from the discharge port side of the hydraulic pump 91.
The direction toward the side is defined as the forward direction. The hydraulic pump 91 is also driven by a motor 92, and its suction port is connected to the reservoir 57, shown as a dot, via a conduit 93 shown in dotted lines. That is, the reservoir 57 serves as a common reservoir of hydraulic fluid for the master cylinder section 3 and booster section 4 described above. Furthermore, as will be described later, the anti-skid piping section 1
It also works as a reservoir for 30.

A stepped hole 9 is provided in the rear part of the first piston 19 in the axial direction.
4 is formed, and this medium diameter hole portion 95 and large diameter hole portion 9
A movable valve body 97 is slidably inserted over 6. The movable valve body 97 has a stepped cylindrical shape and includes, in order from the front, a columnar portion 97d and an annular protrusion 9 as a stepped portion.
7a, a reduced diameter portion 97e, and a rear end portion 97f, and the annular protrusion 97a is a stepped portion, so it has a larger diameter than the outer shape of the columnar portion 97d and protrudes outward, and the reduced diameter portion 97e at the rear thereof has a columnar shape. portion 97d, rear end portion 97
The diameter is smaller than the outer shape of f, and the columnar part 97d on the front end side fits into the medium diameter hole part 95 via the seal ring 99. A small diameter hole portion 121 at the front end of the stepped hole 94 communicates with the auxiliary pressure chamber 27 via an axial through hole 122 . Movable valve body 97
A rubber ring 102 is interposed between the front end of the stepped hole 94 and the step between the small diameter hole 121 and the medium diameter hole 95, and the movable valve body 97 has a stepped hole in the axial direction. A through hole 97c is formed which is aligned and communicates with the small diameter hole portion 121 of 94. A spring receiving ring 98 is disposed in contact with the step between the medium diameter hole 95 and the large diameter hole 96 of the stepped hole 94, and the movable valve body 97
A valve spring 100 is stretched between the movable valve body 97 and an annular protrusion 97a formed on the outer periphery of the movable valve body 97, and urges the movable valve body 97 rearward.

A sleeve 104 is fitted with a seal ring 103 into the rear end opening of the stepped hole 94 of the first piston 19, and is prevented from coming off by a stopper 105. The rear end of the movable valve body 97 fits into the inner hole of the sleeve 104 and is slidable, and the rear end surface to which the rubber sheet 106 is attached is an annular protrusion 107 formed on the front end surface of the input member 9. and are opposed to each other at a predetermined distance when the illustrated device is not in operation. That is, the annular projection 97a of the movable valve body 97 comes into contact with the inner flange 104a formed at the front end of the sleeve 104 by bulging in the inner diameter direction of the recess, so that the movable valve body 97 changes relative to the first piston 19. Rear position is restricted.

An input chamber a is formed around the middle portion of the movable valve body 97 in the large diameter hole portion 96 of the stepped hole 94, and is connected to the accumulator pressure chamber 28 through a through hole 101 formed in the first piston 19. I am in constant communication with. Also, within the sleeve 104, the movable valve body 97
A communication chamber b is formed around the rear end, and this communicates with the boosting pressure chamber 29 via a groove 97b on the outer periphery of the rear end of the movable valve body 97 and a groove 109 on the outer periphery of the front end of the input member 9. We are in constant communication. Annular protrusion 97a of movable valve body 97 and inner flange 1 of sleeve 104
04a constitutes a supply valve, that is, the inner flange portion 104a forms a valve seat, which is closed in the illustrated state, but when opened, the input chamber a and the communication chamber b, that is, the boosting pressure chamber 29 communicate with. In addition, the rubber sheet 1 on the rear end surface of the movable valve body 97
06 and the annular protrusion 107 at the front end of the input member 9 constitute a discharge valve, which is opened in the illustrated state to open the axial passage hole 97c of the movable valve body 97 and the small diameter hole portion of the stepped hole 94 of the first piston 19. The reservoir side and the boosting pressure chamber 29 side communicate with each other via the radial through hole 122 and the auxiliary pressure chamber 27, but when this is closed, the communication between them is cut off. As described above, the input member 9 is biased rearward by the spring 10, but its rear position is restricted by the stopper 108 fixed to the rear end opening of the sleeve 104.

Next, an explanation will be given of the anti-skid piping section 130 which is connected by piping between the master cylinder 1 with a hydraulic booster configured as described above and the front wheels 45 and rear wheels 46.

The second hydraulic pressure generating chamber 41 and the first hydraulic pressure generating chamber 40 of the master cylinder section 3 are connected to first electromagnetic valves 110 and 112 via conduits 43 and 44, respectively. These first solenoid valves 110, 112, front wheels 45, rear wheels 4
Second electromagnetic valves 111 and 113 are connected between the six wheel cylinders 45a and 46a. In addition, the first solenoid valves 110, 112 and the second solenoid valves 111, 1
A third electric throttle valve 117 is connected to the conduit connecting 13 through check valves 118 and 119 and conduits 123 and 124. The inlet of the third solenoid valve 117 is connected to the pressure chamber 29 of the booster section 4 via a conduit 120.
Furthermore, the discharge ports of the second solenoid valves 111 and 113 are connected to the reservoir 57 via fourth solenoid valves 114 and 115 and a conduit 116, respectively.

First, second, third and fourth solenoid valves 110, 11
2, 111, 113, 117, 114, and 115 are 2-position solenoid valves, and each solenoid 110a,
112a, 111a, 113a, 117a, 11
4a and 115a are energized, but can take two states depending on whether they are energized or not. Although not shown, each output terminal of the anti-skid control circuit is connected to solenoids 110a, 112a, 111a, 113.
a, 117a, 114a, and 115a, and each solenoid is energized by an output of “1”.
With an output of "0", each solenoid is not energized.
Based on wheel speed detection signals from wheel speed sensors mounted on the front wheels 45 and rear wheels 46, the anti-skid control circuit determines the skid condition of the wheels and determines whether the brakes should be applied, loosened, or held constant. Decide on the strength. Depending on this determination, an output of "1" or "0" is selectively generated at each output terminal.

First solenoid valves 110, 112 and fourth solenoid valve 11
Reference numeral 5 denotes a so-called "on-off" type valve, which takes the illustrated state A when the solenoids 110a, 112a, and 115a are not energized, and the inlet and outlet are in communication. Also, the solenoid 110a,
When 112a and 115a are excited, they assume the B state, and the inlet and outlet are out of communication. The second solenoid valves 111, 113 and the third solenoid valve 117 are so-called "3-port valves" and have an inlet and an outlet, and an outlet, and when the respective solenoids 11a, 113a, 117a are not excited, the take a state.
That is, in the second solenoid valves 111 and 113, the first solenoid valves 110 and 112 are placed in communication with the wheel cylinders 45a and 46a of the front and rear wheels 45 and 46, and in the third solenoid valve 117, the check valve 118 is placed in communication. ,11
Although the 9 side and the reservoir 57 side are in communication, the inlet and the outlet, that is, the pipe line 120 side and the check valves 118 and 119 side are in a non-communicating state. When the solenoids 111a and 113a are energized, the second electromagnetic valves 111 and 113 take the state D, and the inlet and the outlet are cut off, but the outlet and the discharge port are in communication. That is, the wheel cylinders 45a, 46a side of the front and rear wheels 45, 46 and the fourth solenoid valve 1
14 and 115 side come into communication. Also,
When the solenoid 117a is excited, the third solenoid valve 1
17 assumes state F, and the inlet and outlet are placed in communication. That is, the check valves 118, 119 side and the pipe line 120 side are communicated. Note that the check valves 118, 119 are connected from the third solenoid valve 118, 119 side to the first, second solenoid valves 110, 112, 111,
The direction toward the pipe line between 113 and 113 is defined as the forward direction.

The tandem master cylinder with hydraulic booster according to the embodiment of the present invention is configured as described above,
Next, this action, effect, etc. will be explained.

When the brake is not activated, each part is in the state shown. When the driver depresses a brake pedal (not shown) in this state, the connecting member 12 moves forward and pushes the input member 9. The annular projection 107 at the tip of the input member 9 is connected to the rubber sheet 1 at the tip of the movable valve body 97.
Seated in 06. That is, the discharge valve is closed and the pressure chamber 29 and the reservoir side are placed in a non-communicating state.
When the input member 9 moves further forward, the movable valve body 97 moves to the left relative to the first piston 19 against the elastic force of the valve spring 100 and the rubber ring 102.
The annular projection 97a is separated from the inner flange 104a of the sleeve 104. That is, the supply valve opens, and pressure fluid flows from the input chamber a into the pressure chamber 29 through the communication chamber b, the groove 97b on the outer periphery of the movable valve body 97, and the groove 109 on the outer periphery of the input member 9. As a result, the first piston 19 receives hydraulic pressure at the right end surface of its first large diameter portion 21, and a force for moving it to the left is generated. It is assumed that the motor 92 is driven and the hydraulic pump 91 is operated when the vehicle starts running or when the brake starts operating. Pressure liquid is accumulated in the accumulator 98 at a predetermined pressure.
This is connected to the accumulator pressure chamber 28 via the ball valve 85.
Supplied within. The pressure of the accumulator pressure chamber 28 is constantly applied to the input chamber a through the through hole 101.

As the first piston 19 advances, the input member 9 also advances, and the discharge valve remains closed. Cup seal 26 attached to small diameter portion 23 of first piston 19
passes through the return hole 61, the first hydraulic pressure generating chamber 40
is in a sealed state with respect to the reservoir side, but the pressure in the first hydraulic pressure generating chamber 40 hardly increases at the beginning of forward movement in order to compensate for the liquid loss on the wheel cylinder side. On the other hand, the pressure in the auxiliary pressure chamber 27 increases as the first piston 19 advances, and the pressure difference between the auxiliary pressure chamber 27 and the first hydraulic pressure generating chamber 40 causes the hydraulic fluid to flow through the through hole of the small diameter portion 23 of the first piston 19. 30, deforms the lip portion of the cup seal 26, and flows into the first hydraulic pressure generating chamber 40. As a result, the fluid loss on the wheel cylinder side connected to the output port of the first fluid pressure generating chamber 40 is rapidly compensated for.

When the pressure in the auxiliary pressure chamber 27 reaches the opening pressure of the first valve part 72, the hydraulic fluid in the auxiliary pressure chamber 27 flows through the supply hole 60, the bottom hole part 65 as the second valve chamber, and the through hole 74.
a, between the ball valve 76 and the valve seat 74c, the first valve chamber 7
9 to the reservoir side. When the first piston 19 moves further forward, the pressure in the first hydraulic pressure generating chamber 40, that is, in the wheel cylinder connected thereto, increases rapidly, since the liquid loss on the wheel cylinder side has already been compensated for. The second piston 20 also moves forward together with the first piston 19, but after the first piston 19 moves forward slightly, the first hydraulic pressure generating chamber 40
As the pressure inside begins to rise rapidly, the second piston 2
In addition to the pressure difference before and after 0, the first piston 19 moves forward quickly, compensating for the fluid loss on the wheel cylinder side, and the pressure in the second fluid pressure generating chamber 41 increases almost simultaneously with that in the first fluid pressure generating chamber 40. begins to rise rapidly, and the hydraulic pressures in the first and second hydraulic pressure generating chambers 40, 41 rise equally. In this way, the desired brake can be applied to the vehicle.

When the desired brake is applied, the input F applied to the input member 9 via the connecting member 12 and the force exerted on the input member 9 by the hydraulic pressure Pa introduced into the pressure chamber 29 are balanced, and When the force exerted by the hydraulic pressure Pa on the right end surface of the first piston 19 and the force exerted on the left end surface of the first piston 19 by the hydraulic pressure Pm generated in the first hydraulic pressure generation chamber 40 are balanced, the first piston 1
9 has stopped and the supply valve has also closed. That is, the annular projection 97a of the movable valve body 97 is in contact with the inner flange 104a of the sleeve 104, and the above-mentioned constant hydraulic pressure Pa is introduced into the pressure chamber 29.

That is, in the above balanced state, the following equation holds true.

F=Pa( _S4 - _S3 )...(1) Pm×Sm=Pa×Sa...(2) Here, _S4 is the cross-sectional area of the large diameter portion 9a at the rear end of the input member 9, and _S3 is an annular projection 107 at the tip of the input member 9
Sm is the cross-sectional area of the small-diameter portion 23 of the first piston 19, and Sa is the cross-sectional area S of the large-diameter hole 17 into which the first large-diameter portion 21 of the first piston 19 fits. The above S ₃ is subtracted from (S
−S ₃ ) respectively.

From equations (1) and (2) above, Pm=Sa/Sm×F/S ₄ −S ₃ =S−S ₃ /Sm×F/S ₄ −S ₃ Input F when booster section 4 is not used If the hydraulic pressure in the first hydraulic pressure generating chamber 40 is Pm',
Since Pm'=F/Sm, the following equation holds.

Pm'/Pm'=S- _S3 / _S4 - _S3 .

From the figure, it is clear that S>S ₄ , so it can be seen that the power is doubled.

When the driver releases the brake pedal to release the brake, the input member 9 moves back to the right under the hydraulic pressure in the pressure chamber 29 and the spring force of the spring 10. As a result, the annular projection 107 at the tip is separated from the rubber sheet 106 of the movable valve body 97. That is, the discharge valve opens. The pressure liquid in the pressure chamber 29 flows into the auxiliary pressure chamber 27 through the groove 109 on the outer periphery of the tip of the input member 9, the through hole 97c of the movable valve body 97, and the radial through hole 122.

As the pressure in the pressure chamber 29 decreases, the first piston 19 and the second piston 2 are
0 begins to move back to the right. The pressure in the auxiliary pressure chamber 27 tends to become negative due to the backward movement of the first piston 19, but this is compensated by the inflow of hydraulic fluid from the pressure chamber 29 and the reservoir 57. On the other hand, the first
The hydraulic pressure generation chamber 40 also tries to become negative pressure, but the hydraulic fluid that has flowed into the auxiliary pressure chamber 27 is partially
The liquid passes through the through hole 30 of the small diameter portion 23 of the piston 19, bends the outer edge of the cup seal 26, and flows into the first hydraulic pressure generating chamber 40. This compensates for negative pressure. The second hydraulic pressure generation chamber 41 also tries to become a negative pressure, but this chamber 41 passes through a supply hole 49 and a through hole 42 in the large diameter portion 35 of the second piston 20, and bends the outer edge of the cup seal 37. Then, hydraulic fluid flows in from the reservoir side. This compensates for negative pressure. After the pressure in the pressure chamber 29 becomes zero and the second valve part 73 closes, the hydraulic fluid gradually flows into the auxiliary pressure chamber 27 through the throttle groove 74d, and thus the auxiliary pressure chamber 27, the first The pressure in the hydraulic pressure generating chamber 40 and the second hydraulic pressure generating chamber 41 becomes zero, and each part reaches the state shown in the figure. Note that the aperture groove 74
d also functions to compensate for changes in volume of the hydraulic fluid in the auxiliary pressure chamber 27 due to temperature changes when the first valve portion 72 and the second valve portion 73 are closed.

The above is a case where the vehicle is driving on a road with a normal coefficient of friction and the brake pedal is depressed moderately, but if the vehicle is driving on a road with a small coefficient of friction, such as an ice slope, and the brakes are applied suddenly, the wheels In this embodiment, anti-skid control is performed if there is a risk of locking up.
That is, before the brake pedal is depressed and the hydraulic pressure in the hydraulic pressure generating chambers 40, 41 reaches a constant value according to the input F, the brake is released, maintained at a constant level, and the brake is applied several times.

When the anti-skid control circuit (not shown) determines that the brake is applied too much, the first solenoid valve 11
0, 112 and the solenoids 110a to 113a of the second solenoid valves 111, 113 are excited. In addition, 4
Although anti-skid control may be applied to each wheel individually, in order to make the explanation easier to understand, it is assumed that all wheels 45 and 46 are in the same skid state and are subjected to anti-skid control in the same way.

First solenoid valve 110, 112 and second solenoid valve 11
1,113 now assumes states B and D. Solenoids 114 of other solenoid valves 114, 115, 117
Since a, 115a, and 117a are not excited, they remain in the states of A and E shown in the figure. Wheels 45, 46
The wheel cylinders 45a and 46a of the reservoir 5
7 side, but is not communicated with the hydraulic pressure generating chambers 40, 41 side of the master cylinder section 3. The pressure fluid in the wheel cylinders 45a and 46a is stored in a reservoir 57.
flows out to. This releases the brakes.

When it is determined that the overpressure of the brake is released, the solenoid 114 of the fourth solenoid valve 114, 115
a, 115a is excited. Take the state from A to B. The first and second solenoid valves 110 to 113 remain energized. As a result, the wheel cylinder 45
The hydraulic pressure at that time is contained within a and 46a. That is, the braking force is held constant.

When it is determined that the wheel speed has sufficiently recovered, the third
Solenoid 117a of electromagnetic valve 117 is energized,
Take the state from E to F. First solenoid valve 110, 11
The second solenoid 110a, 112a remains excited, but the second solenoid valve 111, 113 solenoid 111a, 113a and the fourth solenoid valve 11
No. 4,115 solenoids 114a and 115a are demagnetized. As a result, the wheel cylinder 45
a, 46a are not in communication with the reservoir 57 side and the hydraulic pressure generating chambers 40, 41 side of the master cylinder section 3, but are connected to the third solenoid valve 117, the check valves 118, 119, and the second solenoid valves 111, 113. It is in communication with the pressure chamber 29 of the booster section 4 via the booster section 4. This causes pressure fluid to flow from the pressure chamber 29 to the wheel cylinders 45a, 4.
6a, and the braking force increases again.

When the anti-skid control circuit determines that the brake is applied too much, the solenoid 117 of the third solenoid valve 117 is demagnetized, and the second solenoid valve 111,
No. 3 solenoids 111a and 113a are excited. Solenoid 11 of first solenoid valve 110, 112
0a and 112a remain excited. The wheel cylinders 45a, 46a are connected to the fourth solenoid valve 114,
115 to communicate with the reservoir 57, and the pressurized fluid from the wheel cylinders 45a, 46a flows into the reservoir 57.
is discharged to. This releases the brakes.

When it is determined that the over-applied brake has been released, the solenoid 11 of the fourth solenoid valve 114, 115
4a and 115a are excited, and the wheel cylinder 4
5a and 46a are also cut off from the reservoir 57 side, and the braking force is kept constant.

When it is determined that the wheel speed has sufficiently recovered, the third
Solenoid 117a of electromagnetic valve 117 is energized,
Pressure fluid is supplied from the pressure chamber 29 of the booster section 4 to the wheel cylinders 45a, 46a, and the braking force increases again.

In the above way, many times in a short period of time,
This prevents the wheels from locking up due to repeated reductions in braking force, holding it at a constant level, and increasing it.
When the vehicle reaches a desired speed or comes to a stop, the pressure on the brake pedal is released, and the anti-skid control circuit also cuts off the current to the solenoid of the electromagnetic valve that was energized at that time. That is, each electromagnetic valve 110 to 115, 117 assumes the illustrated state. The pressure fluid in the wheel cylinders 45a, 46a is supplied to the second solenoid valves 111, 113 and the first solenoid valve 1.
10 and 112 to the hydraulic pressure generating chambers 40 and 41 of the master cylinder section 3, and excess pressure liquid is returned to the reservoir 57 through the return holes 50 and 61. On the other hand, the pressure chamber 29 of the booster section 4 is discharged to the reservoir 57 side through the through hole 97c of the movable valve body 97, as in the case where the anti-skid control described above is not performed. Thus, the braking force becomes zero.

When performing anti-skid control as described above, the wheel cylinders 45a and 46 are
Pressure fluid is partially discharged from a to the reservoir 57, but the braking force is increased again by supplying pressure fluid from the pressure chamber 29 of the booster section 4, and the hydraulic pressure of the master cylinder section 3 increases. Since the fluid is not supplied from the generation chambers 40, 41, the hydraulic pressure generation chambers 40, 41
There is no possibility that the pistons 19, 20 will be overstroked due to insufficient hydraulic fluid. Since pressurized liquid is supplied into the pressure chamber 29 of the booster section 4 from the hydraulic pump 91 or the accumulator 88 through the open supply valve, the hydraulic pressure does not decrease. That is, during brake operation, the annular protrusion 97b of the movable valve body 97
When the first piston 19 is in contact with the inner flange portion 104a of the sleeve 104, the pressure fluid is discharged from the pressure chamber 29 to the wheel cylinders 45a and 46a, thereby reducing the fluid pressure in the pressure chamber 29. This causes the movable valve body 9 to move to the right.
The annular projection 97b of No. 7 is separated from the inner flange 104a of the sleeve 104, and pressurized fluid flows into the pressure chamber 29 from the input chamber a and is replenished. That is, the sum of the input F to the input member 9, the moving force of the booster section 4 with respect to the first piston 19, and the hydraulic pressure at this time in the hydraulic pressure generating chambers 40, 41 of the master cylinder section 3 are applied to the first piston 19. The state of balance with the reaction force exerted is maintained.

The embodiments of the present invention perform the above-mentioned functions, but also have the following effects.

(1) The movable valve body 97 is substantially columnar, and its front end is fitted into the medium diameter hole 95 of the stepped hole 94 of the first piston 19 via a seal ring 99. Therefore, the force with which the hydraulic pressure in the input chamber a presses the annular projection 97a of the movable valve body 97 against the inner flange 104a of the sleeve 104 can be minimized. That is, the cross-sectional area of the front end side which is the columnar part 97a of the movable valve body 97 is _S5 , and the sleeve 104 of the annular protrusion 97a of the movable valve body 97 is
The seating area on the inner flange portion 104a of S ₆ ,
If the hydraulic pressure in the input chamber a is Pi, and the sum of the spring force of the valve spring 100 and the elastic force of the rubber ring 102 is f, then the annular protrusion 97a of the movable valve body 97 presses against the inner flange 104a of the sleeve 104. The pressing force F' is (S ₆ −S ₅ )×Pi+f, and can be made as small as possible by bringing S ₆ close to S ₅ . That is, by making S ₆ and S ₅ almost the same, F'≈f can be satisfied. Therefore, the force for opening the supply valve configured in this manner by the input member 9 can be minimized, and the operation can be speeded up. Conventionally, a steel ball is used instead of the columnar movable valve body 97, and the force required to open the valve is equal to the seating area of the steel ball x Pi + the spring force of the valve spring, and the entire large steel ball seating area is used to close the input chamber. It was receiving the hydraulic pressure of a. Therefore, the force required to open the valve was large, making it difficult to operate quickly.
However, according to this embodiment, the force required to open the valve is almost entirely generated by the spring force of the valve spring and the rubber ring 10.
Since the force can be made equal to the sum of the two elastic forces, the speed can be greatly improved.

In addition, when performing anti-skid control as in this embodiment, even if pressure fluid is supplied from the pressure chamber 29 to the wheel cylinders 45a, 46a, the opening pressure of the supply valve is small, so pressure immediately flows from the input chamber a side. Fluid can be replenished. As a result, it is possible to cope with an increase in braking force during repeated decreases, constant maintenance, and increases within a short period of time.

(2) When the annular protrusion 97a of the movable valve body 97 is separated from the inner flange 104 of the sleeve 104, the spring force that resists opening the supply valve is generated by the valve spring 100 (coil spring) and the rubber ring. The viscosity coefficient or damping coefficient of the coil spring is small, but that of the rubber ring 102 is large. If the spring force for resisting valve opening is obtained only by the coil spring, if the input member 9 suddenly pushes the movable valve body 97, the coil spring and therefore the movable valve body 97 will move forward more than necessary, and hunting will occur. This may result in unstable control. However, in this embodiment, since the spring force of the rubber ring 102 is also resisted, it is possible to suppress the above-mentioned forward movement more than necessary, and stable control can be achieved even when a sudden force is applied to the input member 9. It can be performed. Further, since the groove 97b functions as a throttle groove, sudden inflow of the working fluid from the input chamber a is prevented, and hunting can also be prevented by this.

(3) When the discharge valve is opened, that is, the input member 9
When the annular projection 107 at the tip of the movable valve body 97 is separated from the rubber sheet 106, the pressure chamber 2
9 is supplied to the through hole 97c of the movable valve body 97 and the first
Small diameter hole 121 of piston 19, auxiliary hydraulic pressure chamber 2
7 to the reservoir 57. No special drain structure is provided in the cylinder body 2 to return the pressure liquid in the pressure chamber 29 to the reservoir 57. Therefore, the configuration for this purpose is simplified.

(4) First solenoid valve 110, 112 and second solenoid valve 11
1, 113 and the pressure chamber 29 of the booster section 4, the third solenoid valve 117 is disposed between the pressure chamber 29 of the booster section 4 and the hydraulic pressure generating chamber 40 of the master cylinder section 3 during anti-skid control. , 41 to increase the braking force of the wheel cylinders again, and it is possible to prevent a shortage of fluid in the hydraulic pressure generating chambers 40, 41.

The embodiments of the present invention have been described above, but of course the present invention is not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the anti-skid piping section 130 was provided to enable anti-skid control, but this may be omitted and used as a normal brake device.

Further, in the above embodiments, a hydraulic booster for assisting the operation of a brake master cylinder has been described, but the present invention is not limited to this and may be used for a clutch, for example.

Further, in the above embodiments, the inner flange portion 104a of the sleeve 104 was used as the valve seat of the supply valve, but a step portion is formed in the inner hole of the first piston 19,
This can also be used as a valve seat. Alternatively, the sleeve 104 may be omitted by changing the shape of the inner hole of the first piston.

Further, in the above embodiment, the cross-sectional area S ₅ on the front end side of the movable valve body 97 = the sealing area of the seal ring 99 with respect to the columnar portion 97d, and the seating area of the discharge valve = the rubber of the annular protrusion 107 of the input member 9. sheet 10
The seating area for the supply valve 6 is smaller than the seating area S ₆ of the supply valve = the seating area of the annular protrusion 97a for the inner flange 104a of the sleeve 104, but the movable valve body 97 and the input member 9 are adjusted so that these are equal. may be configured. In this case, the force required to open the supply valve is equivalent to the spring force of the valve spring 100, making it possible to achieve extremely quick operability.

As described above, according to the hydraulic booster of the present invention, the substantially columnar movable valve body is fitted into the recess of the piston via the sealing member, so that the operating force required to open the valve is reduced. It can be made as small as possible, thus allowing faster operation and improved efficiency.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a master cylinder with a brake hydraulic booster according to an embodiment of the present invention together with an anti-skid piping section, and FIG. 2 is an enlarged side sectional view showing details of the multiple valve device in FIG. 1. It is. In the figure, 1... Master cylinder with brake hydraulic booster, 4... Booster section, 9...
...Input shaft, 19...First piston, 29...Boosting pressure chamber, 94...Stepped hole, 97...Movable valve body,
97a... Annular protrusion, 97d... Column-shaped part, 97
e...Reduced diameter part, 99...Seal ring, 104a
...Inner flange portion of the sleeve 104.

Claims (1)

[Claims] 1 A main body formed with a cylinder hole, a piston that is slidably inserted into the cylinder hole and is biased backward when inactive, and connected to a pressure source formed on the side of the piston that supplies pressurized fluid. an accumulator pressure chamber, a pressure chamber formed at the rear of the piston, a recess provided at the rear side of the piston in communication with the accumulator pressure chamber and the pressure chamber, and a valve device provided in the recess; an input shaft on which the valve device is operable, and the valve device includes a movable valve body inserted into the recess and movable in the axial direction of the piston; It has a valve seat formed on the rear side wall, and a valve spring that biases the movable valve body rearward so as to be seated on the valve seat, and the front side of the valve seat is connected to the accumulator pressure chamber, and the rear side is connected to the accumulator pressure chamber. each communicates with a pressure chamber, and when the input shaft is not operated, the pressure chamber is connected to a reservoir, and when the input shaft is operated forward, the movable valve body is separated from the valve seat to drain the pressure fluid. In the hydraulic booster configured to be introduced into the pressure chamber and move the piston forward, the movable valve body includes a hydraulic booster that extends toward the front side of the piston and fits into the recess through a sealing member. A columnar portion to be fitted together, a reduced diameter portion extending from the columnar portion toward the rear end side and having a smaller diameter than the columnar portion, and a step located between the columnar portion and the reduced diameter portion and capable of being seated on the valve seat. and the valve seat expands radially inward of the recess so that the seating area of the step part with respect to the valve seat and the sealing area of the columnar part by the sealing member are equal to each other. A hydraulic booster made by letting it out.