JPS591872Y2 - hydraulic booster - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a hydraulic booster.

In order to reliably operate a brake device with a small force, a hydraulic pressure booster has been developed that utilizes hydraulic pressure to boost input and output.

In this device, an input rod and an output rod that are slidably connected to each other at their ends are housed in a main body that has an inlet that is connected to a fluid source and an outlet for fluid. A free piston attached to the output rod is fluid-tightly and slidably interposed between the inner wall of the main body and the outer circumferential surface of the input rod to create an inlet-side liquid chamber and a discharge-side liquid chamber within the main body. The two liquid chambers are connected by a communication path of the input rod, and this communication path has a sufficient opening area to prevent pressure difference between the two liquid chambers, and the input rod A rigid valve body is fixedly provided on the output rod, and a valve seat is provided on the output rod, so that when the two rods approach each other, the opening area of the communication passage is narrowed.

When human power is applied to the input rod to advance the input rod into the main body, the valve body of the input rod throttles the communication passage, pinches the free piston, and creates a space between the inlet side liquid chamber and the discharge outlet side liquid chamber. Creates a pressure difference.

The differential pressure applied to the free piston and the hydraulic pressure applied to the output rod due to the rise in hydraulic pressure in the chamber in front of the constriction part were applied to the output rod as an output.

However, in a hydraulic pressure booster with this configuration, at the initial stage of operation, after the input rod starts moving, the communication path is narrowed between the valve body and the valve seat, creating a pressure difference between the two liquid chambers. Since it takes some time for the output to occur, the generation of the output is delayed by that amount of time, causing the user to feel uneasy.

The purpose of the present invention is to provide a hydraulic booster that eliminates the above-mentioned drawbacks, and is characterized by being able to generate output by immediately applying a pressure difference to both liquid chambers at the initial stage of operation. That is.

The invention will be explained in detail below with reference to the illustrated embodiments.

In FIG. 1, a main body 1 having a cylinder IA therein is provided with an inlet 3 and an outlet 4 connected to a fluid source 2 at its ends, respectively, and both open ends of the main body 1 are The guide bodies 5 and 6 are closed by guide bodies 5 and 6, and the guide bodies 5 and 6 are attached to the main body 1 with bolts 7.8, and the inner circumferential surface of the cylinder 1A and the outer circumferential surface of the guide body 5. Confidentiality is maintained.

The inventive band 11 produces the guide sound of the guide body 6 [
The output rod 12 is slidably supported by the guide body 5 and has one end 11A facing into the cylinder 1A, and the output rod 12 is slidably supported by the guide body 5 and has one end 12A facing into the cylinder 1A.

Here, the shaft outer diameter D1 of the implanter 1 to the rod 11 and the shaft outer diameter D2 of the output rod 12 are the same diameter.

A recess 13 is provided in the guide portion 6A of the guide body 6 to surround the input rod 11, and a cup seal rule 14 is provided in the recess 13 to connect the inner peripheral wall of the recess 13 and the input rod 11.
Liquid tightness is maintained with the outer peripheral surface of the

15 has its respective ends connected to the main body 1 and the input rod 11
A dust boot is attached to the terminal end of the input rod 11 and is sheathed on the input rod 11.

A recess 5A is formed in the guide body 5 surrounding the output rod 12, and a cup seal 16 is fitted into the recess 5A.
Liquid tightness between the inner peripheral wall of A and the outer peripheral surface of the output rod 12 is maintained.

Reference numeral 17 denotes a mask cylinder of the brake device. The mask cylinder 17 is fixed to the guide body 5 by a bolt 7 and a nut 1B, and a piston 19 of the mask cylinder 17 is directly engaged with the output rod 12.

A power steering device 20 is connected to the discharge port 4 of the main body 1, and a tank 21 of the fluid source 2 is connected to the fluid discharge port side of the power steering device 20.

A spring 22 is interposed between the guide body 5 and the output rod 12 to bias the output rod 12 in the right direction in the figure.

The input rod 11 is placed on the axis of the input rod 11.
A free piston 23 is slidably fitted and supported to maintain liquid tightness between the outer peripheral surface of the cylinder 1A and the inner peripheral surface of the cylinder 1A, and the free piston 23 connects the inside of the cylinder 1A to a liquid chamber A on the inlet side. and the liquid chamber B on the discharge port side are nationally recognized.

A recess 24 is formed in one end 12A of the output rod 12, into which the one end 11A of the input rod 11 is fitted for relative displacement, and the one end 11A of the implant 1 hero rod 11 is fitted into the recess 24. , the input rod 11 is biased toward the outside of the cylinder by a spring 25.

The edge 24A of the recess 24 is expanded in diameter outward in the radial direction of the output rod 12, and the edge 24A and the cylinder IA
A gap C is secured between the inner circumferential surface of

The edge 24A has an end surface 24 that the free piston 23 comes into contact with.
A valve seat 24C is formed on the end surface 24B at a position radially inward from the portion in contact with the free piston 23.

Here, a gap 1 is formed between the bottom of the recess 24 and the one end 11A of the input rod 11 when the input rod 11 is not in operation.

26 is a seal ring, and the seal ring 26 connects the inner peripheral surface of the recess 24 and the one end 11A of the input rod 11.
A liquid-tight seal is maintained between the outer circumferential surface of the

The free piston 23 is provided with a notch 23A located on the end surface 24B side, and the valve chamber formed by the free piston 23 and the output rod 12 and the liquid chamber B are connected to the notch 23A and the output rod. 12 and the inner peripheral surface of the cylinder 1A.
It communicates with

The free piston 23 is provided with a notch 23B located on the guide body 6 side, and when inactive, this notch 23B is provided.
The liquid chamber A is secured by 3B.

A communication passage 2B that communicates between the liquid chamber A and the valve chamber is formed inside the input rod 11, and ultimately the liquid chambers A and B are communicated with each other by the communication passage 2B.

The effective cross-sectional area of this communication passage 2B is set so as to generate a fluid pressure difference between the liquid chambers A and H.

A flange-shaped valve body 29 is integrally formed on the input rod 11.

The valve body 29 cooperates with the edge 24A of the output rod 12 to form a valve chamber at the opening of the liquid chamber B on the discharge port side of the communication passage 28.

Here, the valve body 29 is configured to approach the valve seat 24C when the input rod 11 moves toward the output rod 12, thereby narrowing the opening area of the liquid chamber A, the valve chamber, and the liquid chamber B. .

A bypass passage 30 is provided between the input rod 11 and the free piston 23.

Here, the bypass passage 30 is formed on the outer circumferential surface of the input rod 11, and when not in operation, the bypass passage 30 communicates between the liquid chambers A and B, and at the initial stage of operation, the bypass passage 30 communicates with the fluid chambers A and B, and at the beginning of operation, the bypass passage 30 is formed on the outer peripheral surface of the input rod 11. It is positioned so as to be closed when the rod 11 is relatively displaced.

When this bypass passage 30 is open, the liquid chamber A
, B communicate with this bypass passage 30 via the communication passage 28, and in the hydraulic pressure booster having the above configuration in which no pressure difference occurs between the liquid chambers A and B, when the hydraulic pressure booster is not in operation, that is, when the input rod 11 is applied with braking force. When the output rod 12 is not applied, the spring force of the spring 22
The two-ton free screw 23 is pressed against the guide body 6, and the input rod 11 is pushed to the right in the figure by the spring force of the spring 25.

At this time, the bypass passage 30 is the liquid chamber A. It connects 8 spaces.

In addition, the output rod 12 and the input rod 11
A gap l is formed between them.

Here, since the outer diameter D1 of the input rod 11 and the outer diameter D2 of the output rod 12 are the same diameter, the pressure inside the cylinder 1A will not fluctuate unless a pressure difference occurs on both sides of the free piston 23. Also, no force to the outside of the cylinder acts on the input rod 11 and the output rod 12.

The fluid from the fluid source 2 is delivered to the power steering device via the inlet 3, the liquid chamber A, the communication passage 28, the bypass passage 30, the valve chamber D, the notch 23A of the free piston 23, the gap C1, the liquid chamber B, and the discharge port 4. 20 and returned to tank 21.

When the driver operates the brake pedal or the like to apply an input to the input rod 11, the input rod 11 moves slightly to the left against the spring 25 in the initial stage of operation.
Since the spring force of the spring 22 is greater than that of the spring 25, the input rod 11 is displaced relative to the output rod 12 and the free piston 23, and the bypass passage 30 is closed.

When the bypass passage 30 is closed, the liquid chambers A and B are communicated only through the communication passage 2B, and due to the throttling action in the communication passage 28, a pressure difference is created between the liquid chambers A and 8. The pressure difference acts on the output rod 12 via the free piston 23, and the output rod 12
A force that pushes outward (to the left), that is, an output is generated.

At this time, the gap between the valve seat 24C and the valve body 29 is hardly narrowed, and therefore the pressure in the valve chamber is approximately equal to that in the liquid chamber B.

Therefore, no resistance force is generated on the input rod 11.

If the external resistance of the output rod 12 is greater than the above output, the output rod 12 will not move.

Therefore, if the pushing force of the input rod 11 is further increased, the spring 25 is bent, the input rod 11 approaches the output rod 12, the gap between the valve seat 24C and the valve body 29 is narrowed, and the effective opening of the communication passage 2B is The area is sandwiched,
The pressure difference between liquid chambers A and B increases, and the force transmitted to the output rod 12, ie, the output, increases.

At this time, the pressure in the valve chamber acts as a resistance to the pushing force of the input rod 11, giving the driver a pedal feeling.

Further, the output is the sum of the force that the output rod 12 receives in the valve chamber and the pressure that the free piston 23 receives.

Therefore, by appropriately selecting the pressure receiving area of the valve chamber and the pressure receiving area of the free piston 23, the output relative to the input can be made constant, and the ratio thereof can also be determined arbitrarily.

Figure 2 compares the input-output characteristics of the device of the present invention with the conventional device. In the conventional device, as shown by the broken line, there is a slight force loss (
An interval t) in the figure occurs.

This is due to the fact that the spring 22 and the spring of the master cylinder (not shown) are bent before the gap between the valve seat and the valve body is narrowed.

On the other hand, in the device of the present invention, as described above, the bypass passage 30 is closed immediately after the input is generated, a pressure difference is created between the liquid chambers A and B, and the output is immediately obtained.

That is, the output jumps up immediately after the input occurs, as shown by the solid line in the figure, and exhibits an increasing characteristic faithful to the input.

Therefore, pedal feel is improved.

When the pressure on the input rod 11 is loosened, the pressure in the valve chamber causes the input rod 11 to shift from the output rod 1.
2, the gap between the valve seat 24C and the valve body 29 becomes larger, the bypass passage 30 opens, and the pressure difference between the liquid chambers A and B decreases.

Therefore, the input rod 11 stops at a pressure position commensurate with the pushing force (input) of the input rod 11, and the forces are balanced.

When the pushing force of the input rod 11 is reduced to zero, the spring 22
, 25, the output rod 12, free piston 23 and input rod 11 return to their initial positions.
becomes inactive.

FIG. 3 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same components as in the above embodiment.

Here, a retainer 31 having the same outer diameter as the input rod 11 is coaxially screwed onto one end 11 A of the implant rod 11, and a flexible valve body 29 is provided between the retainer 31 and the input rod 11. A communication passage 28' is formed by sandwiching the input rod 11 and passing through the input rod 11 and the retainer 31 to form a communication passage 28' which functions in the same manner as the communication passage 28 described above.

Therefore, also in the device of this example, the bypass passage 30 performs the same function as described above.

In this example, when the input rod 11 suddenly moves due to sudden depression of the brake pedal, or
When operating in a state where hydraulic pressure is not supplied to the main body 1 (when the pump fails or the car is stopped), the valve body 29' closes to the valve seat 24.
Even if the valve body 29' is seated on the valve body 29', the valve body 29' is bent, thereby preventing the generation of so-called "rugged noise", reducing impact, and extending the life of the valve body 29'.

FIG. 4 shows another embodiment of the present invention, in which the same reference numerals as in FIG. is being carried out.

Here, the valve flange portion 3 is placed on the axis of the input rod 11.
2A is slidably provided, a free piston 23 is slidably provided on the outside of the valve 32, and a bypass passage 30' is provided on the inner surface of the free piston 23 that communicates the liquid chambers A and B.
The bypass passage 30' can be opened and closed by the valve flange portion 32A of the valve 32.

In addition, in this example, the right guide body is formed integrally with the main body 1, and in the recesses 5A and 13, there are stoppers 33.
34 is fitted.

Therefore, in this example device, when the input rod 11 moves to the left at the initial stage of operation, the valve 32 moves to the left together with the input rod 11 relative to the free piston 23, and the valve flange portion 32A of the valve 32 moves toward the bypass passage 30. Close ′.

As a result, the oil fluid flows only through the communication path 2B', creating a pressure difference between the fluid chambers A and B.

At this time, there is little throttling action in the gap between the valve seat 24C and the valve body 29', and therefore the pressure in the valve chamber is approximately the same as that in the liquid chamber B.

Therefore, the pressure difference acts on the output rod 12 via the free piston 23, and an output is generated.

Therefore, the input-output characteristic shown by the solid line in FIG. 2 is obtained similarly to the above embodiment.

In the above embodiment, a free piston, which is a separate member from the output rod, is inserted into the input rod, but the present invention is not limited to this, and a piston formed integrally with the output rod is inserted into the input rod. It may be slidably inserted into the rod.

As explained above, according to the present invention, a jump-up characteristic of the output appears immediately after the input occurs, and there is almost no loss of the output with respect to the input, and the correspondence between the input and the output is improved, resulting in excellent pedal performance. A hydraulic booster can be provided.

In addition, since the conventional device can be improved to the present device by making some changes, it can be provided at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a hydraulic booster showing an embodiment of the present invention. FIG. 2 is an input-output characteristic diagram showing a comparison between the device of the present invention and the conventional device. FIG. 3 is a vertical cross-sectional view of a main part of a hydraulic booster showing another embodiment of the present invention. FIG. 4 is a longitudinal sectional view of a hydraulic booster showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Main body, 2...Fluid source, 3...Inflow port, 4...
...Discharge port, 11...Input rod, 12...
Output rod, 23...Free piston, 24
C...Valve seat, 2B, 2B'...Communication path, 29.2
9'...Valve body, 30.30'...Bypass passage, 3
2...Valve, 32A...Valve flange, A, B...
liquid chamber.

Claims (1)

[Scope of utility model registration request] a main body having an inflow port connected to a fluid source and a fluid discharge port; an input rod and an output rod whose ends are slidably connected to each other within the main body;
The input rod is slidably and fluid-tightly interposed between the outer peripheral surface of the input rod and the inner wall of the main body, and the main body is divided into an inlet side liquid chamber and a discharge side liquid chamber, and is connected to the output rod. a piston, a communication passage provided in the input rod for communicating the two liquid chambers by applying a pressure difference; It is provided between a valve seat and a valve body that form a throttle part at the opening, and the input rod and the piston, and communicates both the liquid chambers when not in operation, so that the input rod is displaced relative to the piston at the beginning of operation. 1. A hydraulic booster comprising: a bypass passage that is occasionally blocked;