JPS5836612Y2 - Tandem master cylinder with booster - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tandem master cylinder with a borrowing device that is attached to a vehicle or the like and generates high braking pressure proportional to the operating pedal force when a driver performs a braking operation.

Conventionally, in vehicles equipped with a braking system that generates braking pressure only by the driver's pedal effort, when the vehicle weight is a dog or the carrying load is a dog,
Sufficient braking effect cannot be obtained with braking pressure based only on pedal force, so in order to supplement pedal force and generate larger braking pressure to obtain the maximum braking effect, brake pressure intensifiers or pedal force boosters, etc. are used. It is becoming increasingly common to install

However, recently, the above-mentioned devices have the disadvantage of occupying a larger space inside the vehicle body, and in vehicles with multiple braking systems, it is extremely uneconomical to provide each of the above-mentioned devices in one system. For this reason, and also because recent vehicles are equipped with a liquid delivery pump used for power steering, the tandem master cylinder is driven by the liquid delivery pump. A type that integrates a booster has been proposed.

On the other hand, there are two types of tandem master cylinders: a type in which the first piston and the second piston are connected elastically, and a type in which the first piston and the second piston are connected fixedly so that there is no relative displacement.
In order to balance the hydraulic pressure in the braking pressure generating chambers formed before and after the piston, in the former type the first piston itself moves, and in the latter type, opposing hydraulic pressure is created in the braking hydraulic pressure circuit outside the mask cylinder. The balance piston that receives the pressure moves, but the latter type requires special equipment in addition to the tandem master cylinder, so the former type is often used.

Even if a booster is integrated into the tandem master cylinder of the former type as described above, it is difficult to balance the hydraulic pressure in the hydraulic pressure generation chambers formed before and after the first piston. This is essential in order to obtain an even braking effect between the front and rear wheels, or to maintain a preset braking pressure distribution relationship between the front and rear wheels.

In addition, the tension relationship between the compression springs provided before and after the first and second pistons is limited to a predetermined relationship in advance so that the first and second pistons return to preset positions after a braking operation. .

However, as mentioned above, the valve mechanism of the booster is integrated into the second piston of the tandem master cylinder, and the first piston has a balance function as mentioned above, and furthermore, it is installed before and after the first piston. Limiting the tension distribution of the compression spring to a predetermined relationship in advance means that even if the positional relationship between the first piston and the second piston is restricted by using a cage spring, for example, the number of components of the mask cylinder will increase. However, this leads to complexity and complexity in the design stage or multi-step assembly process.

The present invention was developed in view of the above problems, and aims to provide a tandem master cylinder with a booster that satisfies the various required characteristics and has a simplified structure. This is because the first piston in the stepped cylinder hole is suitable for a tandem master cylinder with a hydraulic booster in which the valve device or valve mechanism of the booster is incorporated in the second piston of the tandem master cylinder. The reason is that the pressure of the pressure chamber is made to act directly on both the piston and the second piston.

As a result, the return springs provided on each piston can be provided independently, and the tension distribution between the return springs can be set in various ways, which not only eliminates design complexity, but also eliminates the need for return springs during manufacturing. This makes it possible to use them in combination, and improves workability in assembly work.

In addition, the pressure in the two hydraulic pressure generation chambers is balanced with the pressure in each pressure chamber, so if the return springs are the same, the pressures in the two braking systems can be made almost the same, and the hydraulic pressure generation starts almost immediately. This can be done at the same time, resulting in an even braking effect on the entire wheel, improving safety and reliability.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

1 to 3 are diagrams showing an embodiment of a tandem master cylinder with a booster according to the present invention. The main body of the tandem master cylinder with a booster is indicated by 1, and the main body 1 is A stepped hole 5 consisting of a small diameter part 3 and a large diameter part 4 which are arranged in series.
A small-diameter first piston 6 is slidably and tightly fitted into the small-diameter portion 3 to define a first hydraulic pressure generating chamber 7 .

The first piston 6 has a retainer 8 integrally provided at its front end and a stopper 9 provided so as to protrude from the inner wall of the small diameter hole 3.
By coming into contact with , the compression spring 10 is biased to a predetermined return position.

(In this specification, the front and rear refer to the left side toward the tandem master cylinder shown in FIG. 1 as the front, and the right side as the rear.

) The rear end 6a of the first piston 6 is slidably slidable into the front part of the central through-hole 12 of the hollow second piston 11, which is slidably and tightly fitted into the large diameter part 4 of the stepped hole 5. It is tightly fitted.

A hole 13 having a larger diameter than the center through hole 12 is provided in the front end portion of the second piston 11, and an annular ring 14 is loosely fitted between the inner wall of this hole 13 and the first piston 6. The annular ring 14 has a protrusion 1 provided in the front part within the hole 13.
5 and a protrusion 16 provided on the outer periphery of the rear end 6a of the first piston 6.

The second piston 11 is biased rearward by a compression spring 17 disposed between the stepped portion 2 of the stepped hole 5 and the front end of the second piston 11. The stop ring 20 provided at the opening of the stepped hole 5 is brought into contact with the stop ring 20 provided at the opening of the stepped hole 5 via the fitted closing member 19, and is positioned at a predetermined return position.

A second hydraulic pressure generating chamber 18 is defined in the front side of the second piston 11 in the housing.

A spool 23 having a center hole 28 is slidably inserted into the center through hole 12 of the second piston 11 with a relatively weak spring 21 interposed between it and the first piston 6. The rear end of the piston rod 22 is in contact with the front end surface of the piston rod 22 whose pressure receiving end surface is exposed to the first pressure chamber 24 provided at the rear of the second piston 11 .

The piston rod 22 has a protrusion 25 provided near its front end.
comes into contact with a protrusion 26 provided at the rear end of the second piston 11 and is prevented from retreating.

A second pressure chamber 27 is located between the front end of the spool 23 and the rear end of the first piston 6 through the center through hole 12 of the second piston 11.
This second pressure chamber 27
is constantly communicated with the first pressure chamber 24 through a center hole 28 of the spool 23 and a through hole 29 provided at the front end of the piston rod 22 that matches the center hole 28 .

Further, two grooves 30 and 31 are provided on the outer circumference of the spool 23, and a step 32 is formed between the grooves 30 and 31.

The groove 31 communicates with the central hole 28 of the spool 23 by a radial hole 33.

Grooves 34 and 35 are provided on the inner wall of the central through-hole 12 of the second piston 11 at positions corresponding to the grooves 30 and 31 of the spool 23, and a stepped portion 36 is formed between the grooves 34 and 35. ing.

Further, the second piston 11 has a first recess 40 on its outer periphery.
Second recess 41. A third recess 42 is provided, further comprising:
Auxiliary recesses 40a, 4 are located symmetrically to each recess.
1a and 42a are provided respectively, and the center through hole 1 of the spool 23 and the second piston 11 receives high hydraulic pressure only on one side.
This prevents an increase in sliding resistance due to friction between the two inner walls.

The first recess 40 and the auxiliary recess 40a, the second recess 41 and the auxiliary recess 41a, the third recess 42 and the auxiliary recess 42a
are connected to each other.

Further, the first recess 40 communicates with the groove 34 of the first piston 11 through the hole 37, the second recess 41 communicates with the groove 35 through the hole 38, and the third recess 42 communicates with the groove 34 of the first piston 11 through the hole 37. Second piston 11
It communicates with the groove 30 of the spool through a hole 39 drilled in the spool.

The first recess 40, the hole 37 and the groove 34 form a preliminary chamber;
The second recess 41, hole 38 and groove 35 form a pressureless chamber.

Liquid-tight sealing between the spool 23 and the second piston 11 is achieved by making the gap between the outermost circumferential surface of the spool 23 and the innermost surface of the second piston 11 extremely small, and slight liquid leakage is not allowed. , the liquid leaks into the second recess 41 forming a pressureless chamber.

The first recess 40 is connected to a liquid delivery pump 45 via a hole 43 and a pipe 44, and the second recess 41 is connected to a hole in a projection 67 of a reservoir 66 projecting into the second recess 41. 46
This button constantly communicates with the inside of the reservoir 66, and the reservoir 66 communicates with the liquid storage tank 47 via a pipe 48.

The third recess 42 communicates with the power steering device 51 via a hole 49 provided in the outer peripheral portion of the main body 1 and a pipe 50, and communicates with the tank 47 via the power steering device 51 and a pipe 52.

Reference numerals 64 and 65 indicate inclined valves, and when the mask cylinder is not in operation, the inclined valves 64 and 65 communicate the inside of the reservoir 66 with the first hydraulic pressure generating chamber 7 and the second hydraulic pressure generating chamber 18, and the mask When the cylinder is operated, the above communication is cut off by the elasticity of the spring.

The operation of the inclined valves 64 and 65 is to move the downwardly extending shaft portions 64a and 65a to the flange portion 8a at the front end of the retainer 8 and the second
This is done by engaging and disengaging the flange 11a at the front end of the piston 11.

Reference numeral 53 represents a brake device of one system, and numeral 54 represents a brake device of another system, which are connected to the hydraulic pressure generating chamber of the master cylinder through pipes 55 and 56, respectively.

It was, 57, 58, 59, 60, 61. 62 and 63 all indicate sealing members, and the type of sealing member appropriately selected depending on the suitability of each part is used.

The operation of the tandem master cylinder with the above configuration will be explained.

A liquid delivery pump 45 that constantly sends out pressurized liquid is driven by the prime mover that is the driving source of the vehicle, and the pressurized liquid is sent to the piping 44.
The first recess 40 is reached through the first recess 40 .

In the state shown in FIG. 1, the liquid flows from the hole 37 to the groove 34, and
4, passes through the groove 30, reaches the third recess 42 from the hole 39, passes through the pipe 50 and the power steering device 51, and returns to the tank 4γ via the pipe 52.

The first pressure chamber 24 communicates with the groove 31 through the through hole 29, the center hole 28, and the hole 33, the second pressure chamber 27 communicates with the groove 31 through the center hole 28, and the groove 31 communicates with the groove 31 through the groove 35 and the hole 38. It communicates with the second recess 41 and eventually the hole 46 and the reservoir 6.
6. The first button and the second pressure chambers 24 and 27 are in a pressureless state by communicating with the tank 47 through a pipe 48.

1. When a brake pedal (not shown) is driven to operate the brake and the piston rod 22 moves forward, the spool 23 is pressed by the piston rod 22 and moves forward.

The positional relationship between the groove 34.35 of the second piston 11 and the groove 30.31 of the spool 23 at this time is shown in FIG.

When the spool 23 moves forward, it cuts off communication between the grooves 31 and 35, and communicates the removal grooves 31 and grooves 34 at an interval that allows free flow of liquid.

At the same time, the fluid passage between the groove 34 and the groove 30 is constricted by the stepped portion 32 of the spool 23, and the liquid flowing into the groove 34 through the first recess 40 is restricted from freely flowing into the groove 30. 31 and sends the liquid to the first and second pressure chambers 24 and 27 through the hole 33 button and the center hole 28.

As mentioned above, since the fluid passage from the groove 34 to the groove 30 is constricted, the liquid flowing into the first and second pressure chambers 24 and 27 is directed to the rear end surfaces of the first piston 6 and the second piston 11. In addition to applying liquid pressure, pressure is also applied to the piston rod 22 whose pressure-receiving end surface is exposed to the first pressure chamber 24 .

Braking pressure is generated in the first and second hydraulic pressure generating chambers 7 and 18 by the first and second pistons 6.11, which move forward under the pressure of the liquid pressure acting in each pressure chamber 24.27. The pressure generated in each hydraulic pressure generating chamber 1.18 is transmitted to the brake device 53.54 via piping 55.56.

The pressure generated in the first and second pressure chambers 24,27 is determined by the driving force transmitted to the piston rod 22.

In other words, the reaction force generated when the pressure generated in the pressure chambers 24 and 27 acts on the pressure receiving area of the piston rod 22 is:
It is equal to the driving force of the piston rod 22.

When the driving force is input and the force driving each piston 6.11 from button k is output, the output is the effective pressure receiving area of each piston 6.11 and the hydraulic pressure generated in the pressure chambers 24, 2γ. and increases proportionally to the input.

When the brake is released, the piston rod 22 retreats and the spool 23 simultaneously retreats, and the flow of liquid between the grooves 34 and 30 is no longer restricted, and the flow of liquid between the grooves 34 and 31
The grooves 31 and 35 are communicated with each other.

Therefore, the pressure generated in the first and second pressure chambers 24 and 27 is released by the communication between the grooves 31 and 35, and the pressure that has been generated in the first and second pressure chambers 24 and 27 is released.
11 is retracted by the compression springs 10, 17, the excess liquid in the first and second pressure chambers 24, 2γ flows through the holes 28, grooves 31. The reservoir 66 passes through the groove 35, hole 38, etc.
It is discharged to the tank 47 via the piping 48.

On the other hand, since the groove 34 and the groove 30 communicate without restriction, the pressure liquid sent from the pump 45 through the hole 43 flows through the hole 39, the third recess 42, etc. to the power steering device 51. leading to.

During this series of operations, for example, if a fluid leak occurs in one of the braking systems connected to the hydraulic pressure generation chamber 7 and the system is in a state where no pressure is generated, hydraulic pressure is generated to compensate for the lack of braking force. It is required that the brake fluid pressure in other brake systems connected to the chamber 18 be generated faster and at higher pressures.

In the illustrated embodiment, when the mask cylinder is operated, the system connected to the hydraulic pressure generating chamber 7 breaks down, causing the hydraulic pressure generating chamber 18 to fail.
When the system connected to is normal, the liquid flowing into the first and second pressure chambers 24,27 causes
The first piston 6 is quickly moved forward, and the protrusion 16 of the first piston 6 is brought into contact with the protrusion 15 of the second piston 11 via the annular ring 14.

After that, the first piston 6 and the second piston 11 move forward integrally.

At this time, the pressure inside the second pressure chamber 21 is
It acts on the second piston 11 through the second piston 11.
The pressure that acts to generate pressure in the second hydraulic pressure generating chamber 18 is greater than when both systems are normal, and the pressure in the second hydraulic pressure generating chamber 18 is increased to a higher pressure more quickly. As a result, the brake device 54 exhibits a higher braking effect.

Conversely, if the braking system connected to the 20th hydraulic pressure generating chamber 18 is out of order, the first pressure chamber 2
The second piston 11 moves forward rapidly due to the liquid flowing into the second piston 4, and the stepped portion between the center through hole 12 and the hole 13 of the second piston 11 comes into contact with the protrusion 16 of the first piston 6. 1
The rear and second piston 6.11 move forward together.

At this time, as well as above, the pressure within the first pressure chamber 24 also acts on the first piston 6 via the second piston 11,
The pressure that acts to generate pressure in the 10th hydraulic pressure generation chamber T becomes larger than when both systems are normal, and the pressure in the first hydraulic pressure generation chamber 7 increases faster and at a higher pressure. The brake device 53 also exhibits a higher braking effect.

In the above embodiment, if the liquid delivery pump 45 fails and the boosting effect of the booster cannot be obtained, the protrusion 25 of the piston rod 22 comes into contact with the second piston 11, and the second hydraulic pressure is generated. After creating some pressure in chamber 18, the second
At the same time that the step between the center through hole 12 and the hole 13 of the piston 11 comes into contact with the protrusion 16 of the first piston 6 and pressure starts to be generated in the first hydraulic pressure generating chamber γ, from now on, the first and Braking pressure is generated in the second hydraulic pressure generating chambers 7 and 18 only by the pedal force transmitted to the piston rod 22.

In the embodiment described above, the first piston 6 and the second piston 11 are each provided with separate pressure chambers 27, 24, so that the return compression spring 10.17 is applied to each corresponding piston. It is possible to set the tension distribution between both compression springs independently, and the return position of the piston is accurate because it is provided for each spring. This eliminates complexity and complexity in design and manufacturing, and eliminates the need for extra parts such as cage spring assemblies, making it possible to create a mask cylinder with a reduced number of parts and a simplified structure. It becomes possible.

Furthermore, since the pressure in the pressure chamber directly acts on each piston 6 and 11, the pressure generated in the first hydraulic pressure generation chamber γ and the pressure generated in the second pressure chamber 27 are On the other hand, the second hydraulic pressure generation chamber 18
Since the pressure generated within the hydraulic pressure chamber 24 and the pressure generated within the first pressure chamber 24 are balanced, the pressure within the first and second hydraulic pressure generation chambers 7 and 18 is increased via the pressure within the pressure chamber. It is indirectly balanced, and there is no need to provide a particular balancing mechanism or device to balance the hydraulic pressure in the separate system.

In addition, the part fitted into the small diameter part 3 of the first piston 6 and the part fitted into the center through hole 12 of the second piston 11 may be made separate, or the image part may be eccentric in the radial direction. If they are connected via a permissible connection mechanism, the small diameter part 3 and the large diameter part 4 of the stepped hole 5, or the small diameter part 3 and the center through hole 1 of the second piston 11, in the design stage and the manufacturing stage.
Even if the eccentricity tolerance regarding the axis alignment of the second class is relatively large, there is no problem, and dimensional control becomes extremely easy.

Note that the diameter of the rear end 6a of the first piston 6 is slightly reduced to give the first piston 6 a stepped piston shape, and the diameter of the center through hole 12 of the second piston 11 is slightly reduced to form the second piston 11. The difference between the inner and outer diameters may be increased to form a groove deep enough to insert the sealing member 58, or the first recess 40, the second recess 41 . It is also possible to provide a sufficient difference between the inner and outer diameters to form the third recess 42 and the inner grooves 34-35.

Furthermore, according to the above embodiment, the first piston and the second piston
Although they are separate from the piston, each is directly pressed by the pressure within the pressure chamber, so the positional relationship between the tilt valve 64 and the first piston 6, and the tilt valve 65 and the second piston 1
If the positional relationship of 1 is set the same, each hydraulic pressure generating chamber I,
18 pressure generation can be started at the same time, and by slightly changing the positional relationship, the pressure generation can be started slightly.

Even if one of the two systems breaks down, the braking pressure in the other system can be increased to a higher pressure more quickly, without unnecessarily increasing the braking distance.

As described above, according to the tandem master cylinder with a booster according to the present invention, each of the first piston button and the second piston has a configuration in which the pressure receiving end face is directly exposed to the pressure chamber, so that each piston has an independent A compression spring for return can be provided, which eliminates the complexity and complexity of design related to tension distribution, etc., and also simplifies the structure of the entire mask cylinder, making the manufacturing process easier and simpler. Not only can you obtain the effect of being able to measure the characteristics of the tandem master cylinder, but you can also obtain the effect of satisfying the various characteristics required of a tandem master cylinder, and even more characteristics by making slight changes or additions to the structure. .

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a side sectional view of one embodiment of the present invention, Fig. 2 is a front sectional view conveniently showing the main parts of the embodiment shown in Fig. 1, and Fig. 3 is a front sectional view of the embodiment shown in Fig.
This figure is an enlarged partial side sectional view showing the operating state of the main parts of the embodiment shown in FIG. 1. 1...Main body, 2...Step part, 3...Small diameter part, 4...
・Large diameter portion, 5...Stepped hole, 6...First piston, 6
a... rear end of 6, 7... first hydraulic pressure generating chamber, 8...
...Retainer, 8a--Brim, 9...Stopper 1
0... Compression spring, 11... Second piston, 11a.
...11 tsuba, 12...11 center gadoko L13...
・11 hole, 14... annular ring, 15... 11 protrusion, 16... 6 protrusion, 17... compression spring, 18
... 20th hydraulic pressure generation chamber, 19... Closing member, 20.
...Stop ring, 21...Spring, 22...Piston rod, 23...Spool, 24...First pressure chamber, 25...Protrusion of 22, 26...Protrusion of 11,
27... second pressure chamber, 28... center hole of 23, 2
9...22 through holes, 30.31...23 grooves, 32
...23 step, 33...23 hole, 34,35...
...11 groove, 36... step, 37.3B, 39.
...11 holes, 40...first recess, 41...second
recess, 42... third recess, 43... hole, 44...
...Piping, 45...Liquid delivery pump, 46...66
hole, 47...Liquid storage tank, 48...Piping, 4
9... 11 holes, 50... Piping, 51... Power steering device, 52... Piping, 53, 54... Brake device, 55.56... Piping, 57, 58, 59゜60
; 61, 62, 63... Sealing member, 64... Inclined valve, 64a... Shaft portion of 64, 65... Inclined valve, 65a
...65 shaft part, 66...reservoir, 67...6
6 protrusions, 40a, 41a, 42a... auxiliary recesses.

Claims (1)

[Scope of utility model registration request] A first piston and a second piston define two hydraulic pressure generating chambers in the cylinder hole and are slidably inserted, and a second piston is formed on the rear side of the second piston that is inserted into the rear side of the cylinder hole. A pressure chamber, a piston rod whose pressure-receiving end surface is exposed to the pressure chamber, and a valve device installed in the second piston to introduce pressure from a liquid pressure source into the pressure chamber in accordance with an input from the piston rod. In the mask cylinder with a booster, the rear end of the first piston is slidably and in close contact with a recess provided on the front end side of the second piston.
A tandem master cylinder with a booster, which defines a pressure chamber and is provided with a passage connecting the second pressure chamber to the pressure chamber.