JPH0671880B2 - Hydraulic booster - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic booster used for assisting the operation of a master cylinder or the like in a vehicle or the like.

[Prior art]

For example, a hydraulic booster disclosed in JP-A-60-176859 includes a cylinder body having a cylinder hole, a piston slidably inserted in the cylinder hole and defining a servo chamber on one end side, An abutting portion formed in the cylinder body with which one end of the piston abuts when the piston is in the return position and inoperative, a valve hole provided in the piston and connected to the servo chamber, and a valve hole disposed in the valve hole. A valve device for controlling communication / interruption with respect to an external pressure source and a pressure release source of the servo chamber according to an input; and a control member fitted to the valve hole and transmitting an operation input from the outside to the valve device, The valve device includes a supply valve seat located between the servo chamber provided on the inner wall of the valve hole and the external pressure source, and the servo chamber provided at the end of the control member and the pressure release source. Discharge located between and A seat, a valve body that penetrates the supply valve seat and has one end extending toward the discharge valve seat, and is provided so as to be movable in the axial direction; A seatable first seating portion, a second seating portion that can be seated on and off the discharge valve seat formed at one end of the valve body, and the valve body is biased toward the control member to First
And a valve spring for seating the seating portion on the supply valve seat, and the control member for biasing the second seating portion and the discharge valve seat toward the side opposite to the valve body. And a return spring.

[Problems to be solved by the invention]

However, in the above device, the discharge valve seat and the valve body are separated from each other in the axial direction in order to secure the passage area required for loosening.
This distance of separation is large, and the play in the initial stage of operation is large.

Further, in order to eliminate the play at the initial stage of operation, the exhaust valve seat and the valve body may be seated in the non-operating state, but the dimensions of each member may change due to temperature changes during the cycle. There is a problem that the seating positions of the discharge valve seat and the valve body change, and the supply valve opens carelessly.

The present invention has been made in view of such a problem, and provides a hydraulic booster capable of eliminating play at the initial stage of operation and reducing changes in seating positions of a discharge valve seat and a valve body even when ambient temperature changes. The purpose is to do.

[Means for solving problems]

The above-mentioned object is, in the above-mentioned configuration, when the piston is in the return position in the cylinder body and is inoperative, engages with the control member and restricts the movement against the biasing force of the return spring. Is provided with an engaging portion for seating on the discharge valve seat, and the engaging portion is located at an intermediate position between the seating position of the second seating portion and the contact portion with respect to the discharge valve. This is achieved by a hydraulic booster adapted to engage the control member on the contact side.

[Work]

Since the movement amount of the control member for shutting off the servo chamber from the pressure release source becomes zero according to the operation input, when the operation member is applied and the control member starts moving, the valve body is immediately moved through the control member. The external pressure source communicates with the servo chamber, which is separated from the supply valve seat and isolated from the pressure release source. Therefore, play at the beginning of operation is reduced to improve operability,
The braking force can be raised quickly.

In addition, one end of the valve element extends through the supply valve seat toward the discharge valve seat provided in the control member, and at one end thereof, a second seat portion that can be seated on and released from the discharge valve seat is provided, and the second seat part is provided. The engagement position with the mating part is located closer to the contact part than the seating position of the valve body with respect to the discharge valve seat and the intermediate position between the piston, the cylinder body and the contact part. The axial distance to the part can be shortened. Therefore, even if the ambient temperature changes, the displacement of the seating position of the valve body with respect to the discharge valve seat can be reduced, and the supply valve does not open accidentally.

〔Example〕

Hereinafter, a hydraulic booster according to an embodiment of the present invention will be described with reference to the drawings.

In the figure, the apparatus of the present embodiment is indicated by (1) as a whole, and a master cylinder part (3) is shown on the left side of the cylinder body (2) and its details are shown on the right side of FIG. Is provided with a booster section (4). 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 (6) is fixed to the cylinder body (2) by a stop ring (16) with a seal ring (7) interposed, and the entire device is fixed to a toe board (not shown).

An input member (9) as a shaft-shaped control member is slidably fitted in the cup seal (11) in the center through hole (8) of the lid body (6). (In this specification, the front means the left side in the drawing, and the rear side means the right side.) Further, in the recess (15) formed at the rear end of the input member (9). The rod portion (13) of the connecting member, which is connected to a brake pedal (not shown), receives the tip of the rod portion (13) and is prevented from coming off by the ring (12). A boot (14) is fixed between the rod portion (13) and the rear end of the main body (2) to prevent dust.

The stepped hole (5) of the cylinder body (2) is composed of a large diameter hole portion (17) into which the lid body (6) is fitted and a small diameter hole portion (18) which occupies most of the large diameter hole portion (17). ) And the first piston (19) are slidably fitted over the small diameter hole (18), and the second piston (20) is slidably fitted on the left side of the small diameter hole (18). I am fit. The first piston (19) has a first large diameter portion (21) (see FIG. 2) at the rear end portion, the intermediate portion and the front end portion, respectively.
It has a second large diameter portion (22) and a third large diameter portion (23), and has seal rings (24) (25) (see FIG. 2) and a cup seal (2
6) is attached. Thus, a pressureless chamber (27) is formed between the second large diameter portion (22) and the third large diameter portion (23), and the second large diameter portion (22) and the first large diameter portion (21) are formed. ) And an accumulator pressure chamber (28) is formed. Also, the first large diameter portion (21)
As a servo chamber between the cover and the lid (6), a booster pressure chamber (2
9) (See FIG. 2) is formed. These non-pressure chamber (27), no pressure chamber only (27) of the accumulator chamber (28) and the booster pressure chamber (29) is belongs to the master cylinder unit (3), the free chamber ( 27) to define the first piston (1
The front half of 9) belongs to the master cylinder section (3),
The details of the master cylinder section (3) will be described below. A bolt (31) is screwed onto the front end of the first piston (19), a generally cup-shaped spring bearing (33) is engaged with the head of the bolt (31), and a ring is attached to the shaft. -Shaped spring bearings (32) are fitted together, and a spring (34) is stretched between these spring bearings (32) (32) in a compressed state, so that the spring bearing (33) is attached to the second piston (20). The spring receiver (32) is pressed against the front end of the first piston (19) at the rear end. Further, the cup seal (26) is attached to the first large diameter portion (23) as a head portion formed at the front end portion of the first piston (19) in contact therewith, and the second piston (20) ) Rear large diameter part (36)
Also, by mounting the cup seal (38), a first hydraulic pressure generating chamber (40) is formed between the first piston (19) and the second piston (20).

The cup seal (37) is also attached to the large diameter portion (35) of the front end of the second piston (20), whereby a pressureless chamber is provided between the large diameter portion (35) of the front end and the large diameter portion (36) of the rear end. (39) is formed, and the 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) has a return spring (4) 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).
It is biased to the right by 7). An output port (42) is formed at the front end of the cylinder body (2) so as to communicate with the second hydraulic pressure generating chamber (41), and the output port (42) is connected to the wheel cylinder of the front wheel via a conduit (not shown). Further, although not shown, another output port is formed in the cylinder body (2) so as to communicate with the first hydraulic pressure generating chamber (40) , which is connected to the wheel cylinder of the rear wheel through a pipe line (not shown). Connected.

On the upper wall of the front end of the cylinder body (2), the boss (5
1) is formed, and the liquid connection hole (52) communicates with the second hydraulic pressure generation chamber (41) through the return hole (50) when the normal brake (not shown) is operated, and the replenishment hole (49). It is in constant communication with the pressureless chamber (39) via. Further, the connecting cylinder portion (55) of the reservoir (54) is press-fitted into the liquid connection hole (52) via the grommet seal (53).

The reservoir (54) has a known structure, and has a cylindrical main body (43).
The upper opening of the chamber is covered by the cap (44), and the inside is the liquid level detection chamber (58) , the first and second reservoir chambers (45).
It is defined in (46).

A boss portion (62) higher than the above-mentioned boss portion (51) is formed on the upper wall portion of the intermediate portion of the cylinder body (2), and the liquid connection hole (63) of the boss portion (63) is formed through the return hole (61). It is in communication with the hydraulic pressure generating chamber (40) and is always in communication with the non-pressure chamber (27) through the supply hole (60). Further, the other connection cylinder portion (65) of the reservoir (54) is press-fitted into the upper portion of the liquid connection hole (63) via the grommet seal (64).

Next, the details of the booster unit (4) will be described with reference to FIGS. 1 and 2.

The first piston (19) is one of the main components in the booster unit (4), but it is located above the accumulator pressure chamber (28) formed on the rear side and on the rear side of the cylinder and is located above the cylinder. A boss (83) is formed on the main body (2), and a connecting member (84) is screwed to the boss. A check valve consisting of a ball valve (85) and a valve spring (86) is arranged in the boss (83), and is connected via the communication hole (83a) with the direction from the upper side to the lower side as the forward direction. The conduit (87) side connected to the member (84) can communicate with the accumulator pressure chamber (28) . An accumulator (88) is connected to the pipe line (87), and a discharge port of the hydraulic pump (91) is connected to the pipe line (89). The hydraulic pump (91) is driven by a motor (not shown), and its suction port connects the pipe line (93) to the second reservoir (90). The reservoir (90) is connected to the connection port (43a) of the first reservoir (54) via the pipe line (92). The first reservoir (54) acts as a common reservoir of hydraulic fluid for the master cylinder section (3) and booster section (4), but the second reservoir (90) is for the servo section. It works to ensure the minimum amount of fluid, and even if the brake system connected to one reservoir chamber (46) fails and fluid leaks and it becomes impossible to supply fluid to the servo section, a hydraulic pump. Since (91) has already sucked and stored a sufficient amount of liquid in the second reservoir (90) for normal operation of the servo section, this works for the operation of the servo section.

A stepped hole (94) is formed in the rear portion of the first piston (19) in the axial direction, and the movable valve body (97) is slidable over the small diameter hole portion (95) and the medium diameter hole portion (96). Has been inserted. The front end of the small-diameter hole (9
5) is fitted. The small diameter hole portion (95) of the stepped hole (94) communicates with the pressureless chamber (27) through the radial passage hole (122). Further, the movable valve body (97) is formed with a through hole (97c) axially communicating with the small diameter hole portion (95) of the stepped hole (94). Small diameter hole (95) and medium diameter hole (9) of stepped hole (94)
A spring bearing ring (98) is arranged so that the seal ring (99) is brought into contact with a step portion between the ring projection (6) and the annular protrusion (which is formed on the outer peripheral portion of the movable valve body (97). A valve spring (100) is stretched between it and 97a), and urges the movable valve body (97) rearward.

A sleeve (104) is fitted and fitted with a seal ring (103) at the rear end opening of the stepped hole (94) of the first piston (19), and this is prevented from coming off by a stopper (105). ing. The rear end of the movable valve body (97) is slidable in the inner hole of the sleeve (104), and the rear end thereof is the input member (9).
Aligned with a recess (107) formed in the front end of the. The movable valve body (97) has a sleeve (10a) with its annular projection (97a).
By contacting the front end (104a) of 4),
The rear position relative to the piston (19) is restricted.

Within the medium diameter hole (96) of the stepped hole (94), the movable valve body (9
An input chamber a is formed around the middle portion of 7) and is always in communication with the accumulator pressure chamber (28) through the through hole (101) formed in the first piston (19). A communication chamber b is formed around the sleeve (104) and is always in communication with the boosting pressure chamber (29) . A supply valve is formed by the annular projection (97a) of the movable valve body (97) and the front end (104a) of the sleeve (104), which is closed in the state shown in the drawing, but is formed in the sleeve (104) when opened. Perforated holes (109)
Via input chamber a and communication chamber b, that is, pressure chamber for boosting (29)
Communicate with. Further, a discharge valve is constituted by the rear end portion of the movable valve body (97) and the tapered valve seat (107a) formed at the opening end portion of the recess (107) at the front end of the input member (9), The state shown is inactive but closed according to the invention. The through hole (150) formed in the sleeve (104), the axial through hole (97c) of the movable valve body (97), and the first piston (1
9) Stepped hole (94) Small diameter hole (95), radial through hole (1
22), via the pressureless chamber (27) to the reservoir side and booster pressure chamber (2
Although it is possible to communicate with the 9) side, when the input member (9) advances and the valve seat (107a) comes into pressure contact with the rear end of the movable valve body (97), the communication between them is cut off. The input member (9) is biased rearward by a spring (10) stretched between the flange portion (9a) and the sleeve (104), and the rear end of the first piston (19) comes into contact with the lid. The rear position is regulated by a stopper member (106) fixed to the end surface of the body (6). That is, the distance between the rear end of the movable valve body (97) and the valve seat (107a) is set to zero.

As described above, the piston (1
When 9) is in the return position and is inoperative, it engages with the input member (9) as a control member to restrict the movement against the urging force of the return spring (10) and to move as a second seating portion. The right end portion of the body (97) is provided with a stopper member (106) as an engaging portion for seating on the discharge valve seat (107a), and this engaging portion serves as a second seat portion (first seat portion) for the discharge valve. Is the movable valve body (9
7) above the intermediate position between the seating position of the annular projection (97a) (right end) and the contact portion, that is, the inner end surface of the lid (6) with which the right end surface of the piston (19) contacts. The control member is engaged on the contact side.

The hydraulic booster according to the embodiment of the present invention is configured as described above, and its operation will be described below.

The input member (9) moves to the left in FIG. 2 when a brake pedal (not shown) is depressed. The valve seat (107) formed at the front end of the input member (9) when the brake is not operated.
a) and the rear end of the movable valve body (97) are seated,
b is in a state of being cut off from the reservoir side. When the input member (9) moves forward in such a state, the movable valve body (97) is pushed to separate the annular protrusion (97a) from the valve seat (104a). As a result, the pressure liquid is introduced from the accumulator pressure chamber into the communication chamber b . That is, this pressure liquid is introduced into the booster pressure chamber (29) , and a hydraulic pressure is applied to the right end pressure receiving portion of the piston (19) to give a moving force to the left in the figure. In this way, the hydraulic pressure in the booster pressure chamber (29) increases as the input member (9) advances.

The operation until the desired braking force is obtained will be further described. When the input member (9) advances as described above, the movable valve body (97) resists the elastic force of the valve spring (100) to move the first piston ( 19) moves to the left relative to the annular projection (97a) and separates from the front end (104a) of the sleeve (104). That is, the supply valve is opened, and the pressure liquid from the input chamber a flows into the pressure chamber (29) through the communication chamber b . This makes the first
The piston (19) receives the liquid pressure at the right end surface of the first large diameter portion (21), and a moving force to the left occurs. It is assumed that the motor is driven and the hydraulic pump (91) is operated when the vehicle starts running or when the brake starts operating. The pump (91) is driven by the motor so that the accumulator (88) stores a pressure in a predetermined range, for example, a pressure of 120 to 150 Kgf / cm ² . Second reservoir (90)
A predetermined amount of liquid is stored in. The pressure liquid is supplied into the accumulator pressure chamber (28) via the ball valve (85). Input room
The pressure of the accumulator pressure chamber (28) is constantly applied to a through the through hole (101).

As the first piston (19) advances, the input member (9) also advances, and the discharge valve remains closed. The cup seal (26) attached to the third large diameter portion (23) of the first piston (19) and the cup seal (37) attached to the large diameter portion of the second piston (20) are respectively returned holes (61). ) (50), the first and second hydraulic pressure generating chambers (40) and (41) are closed to the reservoir side, and thereafter, the first and second hydraulic pressure generating chambers (40) and (41) are advanced as the pistons (19) and (20) move forward. The hydraulic pressure in the hydraulic pressure generating chambers (40) (41) rises equally. The desired brake is thus applied to the vehicle.

When the desired brake is applied, the input applied to the input member (9) via the connecting member (12) and the hydraulic pressure Pa introduced into the boosting pressure chamber (29) are applied to the input member (9). )
The force exerted on the right end surface of the first piston (19) and the hydraulic pressure Pm generated in the first hydraulic pressure generation chamber (40) are proportional to the left end surface of the first piston (19). The first piston (19) is stopped, and the supply valve is also closed. That is, the annular protrusion (97a) of the movable valve body (97) is in contact with the front end (104a) of the sleeve (104), and the constant pressure Pa described above is applied to the booster pressure chamber (29). Has been introduced. This gives a boosting effect.

When the driver returns the brake pedal to release the brake, the input member (9) lifts the hydraulic pressure of the boosting pressure chamber (29) and the spring force of the spring (10) to return to the right. . As a result, the recess (107) at the tip is separated from the rear end surface of the movable valve body (97). That is, the discharge valve opens. Booster Pressure Chamber (29)
The pressurized liquid flows into the pressureless chamber (27) through the communication hole (97c) and the radial through hole (122) of the movable valve body (97).

As the pressure in the boost pressure chamber (29) decreases, the first hydraulic pressure generating chamber
The first piston (19) and the second piston (20) move to the right under the hydraulic pressure of (40) and the spring force of the return spring (47), and take the position shown in the figure to loosen the brake.

The return position of the input member (9) is restricted by the stopper member (105), and the recess (107) at the tip thereof is movable valve body (97).
It comes into contact with the rear end.

The recess (107) of the input member (9) is the movable body valve (97).
The piston (19) moves to the left relative to the input member (9) by the pressure of the boosting pressure chamber (29), and is regulated so as to come into contact with the rear end of the rear end and stop. As a result, the discharge valve is opened and the pressure fluid is returned to the reservoir side, so that the fluid pressure in the booster fluid pressure chamber (29) can be made substantially zero. That is,
The residual pressure can be almost zero.

The embodiment of the present invention performs the above-mentioned actions,
Further, the following effects are exhibited. That is, as shown in FIG. 2, when the device is not operating, the rear end of the movable valve body (97) and the valve seat (107a) formed in the recess (107) of the input member (9) are in contact with each other. Therefore, when the brake is applied, the supply valve can be opened immediately when the input member (9) starts moving, so that the operating characteristics of the brake can be made extremely excellent. If the distance between the rear end of the movable valve element and the valve seat formed at the tip of the input member is large as in the conventional case, the input member must be moved considerably in order to bring them into contact with each other first, that is, the play is Since it is large, the brake operability is poor, but according to the present embodiment, it can be greatly improved.

A second seat portion that can be separated from and seated in the discharge valve seat is provided at one end of the valve body (97), and the engagement position with the stopper member (106) engaged with the control member (9) is determined by the valve body (97). ) Is located closer to the contact portion than the intermediate position between the seating position for the discharge valve seat, the piston (19), and the contact portion with the cylinder body (2). The axial distance between and can be shortened. Therefore, even if the ambient temperature changes, the discharge valve seat (107) of the valve body (97)
The displacement of the seating position with respect to a) can be reduced,
The supply valve does not open carelessly.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the valve seat is formed by the conical recess formed at the tip of the input member as the discharge valve, and the discharge valve is constituted by this and the rear end surface of the movable valve body. Instead of this, a known valve structure can be used.
Further, the hydraulic booster to which the present invention is applied is not limited to the one shown in the drawing, but can be applied to a general hydraulic booster.

〔The invention's effect〕

As described above, according to the hydraulic booster of the present invention, the initial operating characteristics can be made much better than before, and the operation for improving the operability and obtaining the desired braking force can be made smoother and easier. It can be done.

That is, when the brake is released, the control member is allowed to move in the direction in which the discharge valve seat and the valve body are separated from each other by the biasing force of the return spring until the piston reaches the return position. Since the pressure in the servo chamber is discharged to the pressure release source before the inoperative state and no residual pressure is generated in the servo chamber, a stable boosting action can be obtained according to a change in the operation input.

Further, the axial distance between the abutment portion and the engagement portion can be shortened. Therefore, even if the ambient temperature changes, the displacement of the seating position of the valve body with respect to the discharge valve seat can be reduced, and the supply valve can be carelessly supplied. Will never open.

[Brief description of drawings]

FIG. 1 is a sectional view showing the entire hydraulic booster according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the booster section in FIG. In the figure, (9) …… input member (10) …… spring (97) …… movable valve body (106) …… stopper member

Claims (1)

[Claims] 1. A cylinder body having a cylinder hole, a piston slidably inserted into the cylinder hole to define a servo chamber on one end side, and a piston formed in the cylinder body at which the piston is in a return position. An abutting portion with which one end of the piston sometimes abuts, a valve hole provided in the piston for communicating with the servo chamber, and a communication / interruption of an external pressure source and a pressure release source of the servo chamber arranged in the valve hole. And a control member that fits into the valve hole and transmits an operation input from the outside to the valve device, wherein the valve device is provided on the inner wall of the valve hole. A supply valve seat located between the chamber and the external pressure source, a discharge valve seat provided at the end of the control member between the servo chamber and the pressure release source, and the supply valve seat. Penetration and one end is discharged A valve body extending toward the seat and movably in the axial direction; a first seating portion formed at an intermediate portion of the valve body and seatable on and away from the supply valve seat; and one end of the valve body. A second seat portion that is formed and can be seated on and off the discharge valve seat; and a valve spring that biases the valve body toward the control member to seat the first seat portion on the supply valve seat. A hydraulic booster having a return spring that biases the control member toward the side opposite to the valve body so as to separate the second seat portion and the discharge valve seat, When the piston is in the return position in the cylinder body and is inoperative, the second seat portion is seated on the discharge valve seat by engaging with the control member and restricting movement against the biasing force of the return spring. And an engaging portion that allows the engaging portion to move forward and backward with respect to the seating position of the second seat portion with respect to the discharge valve. Hydraulic booster which is adapted to engage the control member in the contact portion side than the intermediate position between the abutment.