JPS6146752A - Hydraulic booster - Google Patents

Abstract

PURPOSE:To reduce a degree of valve opening resistance due to input hydraulic pressure, by staggering the valve opening timing of plural inlet valves interposingly installed in an oil passage lying between input and output hydraulic chambers. CONSTITUTION:When a brake pedal is operated, a valve piston 35 and an interlocking ring 48 are pushingly moved forward via an input rod 36, and from relations of L3<L1 and L1<L2, first an annular groove 39 is intercepted from an outlet port 38 whereby an outlet valve 27 is closed. Next, the interlocking ring 48 comes into contact with a rear end of an operating rod 321 of a first inlet valve 261, pushing this forward, whereby a ball valve body 301 is separated from its valve seat. Afterward, the interlocking ring 48 comes into contact with a rear end of an operating rod 322, pushing this forward, whereby a ball valve body 302 is separated from its valve seat. Thus, these first and second inlet valves 261 and 262 are opened in order.

Description

DETAILED DESCRIPTION OF THE INVENTION A0 Object of the Invention (1) Industrial Application Field The present invention relates to a hydraulic booster used for boosting a brake mask cylinder of an automobile, in particular,
a booster cylinder; a booster piston that is slid into a cylinder hole of the booster cylinder and partitions its interior into a front input hydraulic chamber connected to a hydraulic pressure source; and a rear output hydraulic chamber having a larger pressure receiving area; The input rod is connected to the pusher piston so that it can advance and retreat: It is interposed in the oil passage connecting the input and output hydraulic chambers, and is linked to the input rod so that it closes when the input rod retreats and opens when it moves forward. an inlet valve that connects the output hydraulic pressure chamber and the oil tank; and an outlet valve that is interlocked with the input rod so that it opens when the input rod retreats and closes when the input rod moves forward; This invention relates to an inlet valve configured as a ball type.

(2) Prior Art Conventionally, in this type of booster, one ball-type inlet valve or two ball-type inlet valves with negative opening timings are installed.

(3) Problems to be Solved by the Invention In general, when a ball-type inlet valve is closed, the hydraulic pressure in the input hydraulic chamber acts on the ball valve body as a valve-closing force; It is determined by the product of the cross-sectional area at the seating point on the valve seat and the oil pressure, and this becomes the main opening resistance of the inlet valve. Therefore, if a small-diameter ball valve body is used, the valve closing force due to the hydraulic pressure is small, and the valve can be opened with a small input, but on the other hand, the valve hole that is opened and closed by the ball valve body is inevitably Since the inlet valve must be formed to be very thin, flow path resistance increases, resulting in disadvantages such as a slow hydraulic pressure transmission speed when the inlet valve is opened and a decrease in the operational response of the booster. On the other hand, if the valve hole is made thicker in order to improve the operational response of the booster, a ball valve body with a large diameter must be used, which results in high valve opening resistance and operability. This causes inconvenience that reduces the

For this reason, conventional boosters are forced to sacrifice either operational response or operability.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a booster that can satisfy both operational response and operability.

B0 Structure of the Invention (1) Means for Solving Problems The present invention provides at least two inlet valves connected in parallel,
It is characterized in that it is interposed in the oil passage between the output hydraulic chambers, and its inlet valves are linked to the input rod so that their opening timings are shifted from each other.

(2) Operation When the input rod moves forward, the outlet valve closes and the inlet valve, which opens earlier, opens. At the initial stage, the input and output hydraulic chambers have approximately the same pressure, so the valve opening timing The opening resistance of the slow inlet valve is extremely small. Therefore, at the next stage when the input rod moves further forward, the inlet valve that opens later can be opened with almost no resistance.

If all the inlet valves are opened, the flow resistance between the input and output hydraulic chambers is significantly reduced, so the hydraulic pressure in the input hydraulic chamber is quickly supplied to the output hydraulic chamber.

(3) Embodiment An embodiment of the present invention will now be described with reference to the drawings. First, in FIG. An oil tank 2 is formed, and the lower half thereof is separated by a front oil tank 2.alpha. by a partition wall 2α. and rear oil sump 2. It is divided into

The cylinder hole 3 of the cylinder body 1 has a small diameter hole 3α passing directly below the oil tank 2, and a large diameter hole 3 connected to the rear end of the small diameter hole 3a.
h and is formed in a stepped manner. Front oil sump 2 is installed in the small diameter hole 3α.
．． The entire front mask piston 4 defines a front hydraulic chamber (not shown) which is supplied with oil between the front end wall of the cylinder hole 3 and the rear hydraulic chamber 6 which is supplied with oil from the rear oil reservoir 22. The front end of the rear mask piston 5 defined between the front mask piston 4, i.e., the small diameter piston part 5α, is slid together, and the rear end of the rear mask piston 5, i.e., the large diameter piston part, is fitted into the large diameter hole 3h. 5b are slid together. Therefore, the rear mask piston 5 is composed of a small-diameter piston portion 5α and a large-diameter piston portion 5b having a larger diameter.

A supply oil chamber 7 is defined in the large diameter hole 3b of both piston portions 5α, 5h, and this oil chamber 7 is communicated with the rear oil reservoir 22 via an oil passage 8.

An elastic piston cup 9 is provided on the front surface of the small diameter piston portion 5α.
is installed, and an IJ-float 10 is bored in the cylinder body 1 and opens just before this piston cup 9 at the retraction limit of the rear mask piston 5 to communicate between the rear hydraulic chamber 6 and the oil passage 8. In the small diameter piston part 5a,
A through hole 11 is bored through which the supply oil chamber 7 communicates with the back of the piston cup 9.

The front hydraulic chamber (not shown) and the rear hydraulic chamber 6 house return springs 12 that bias the front and rear mask pistons 4.5 in the backward direction, respectively.

When the rear mask piston 5 is pushed forward and the piston cup 9 crosses the opening of the relief port 10, hydraulic pressure is generated in the rear hydraulic chamber 6.
and a brake hydraulic circuit (not shown) in communication with the brake hydraulic pressure circuit (not shown).

When the rear mask piston 5 retreats from the forward position and the rear hydraulic chamber 6 is depressurized, the outer periphery of the piston cup 9 bends forward due to the pressure difference between the front and rear, creating a gap between it and the inner surface of the cylinder hole 3. As a result, the rear oil sump 2. oil is in oil path 8,
It flows into the rear hydraulic chamber 6 through the supply oil chamber 1 and the through hole 11,
Hydraulic oil is replenished, and if excessive replenishment occurs, the excess is returned to the rear oil sump 22 through the relief port 10.

The front mask piston 4 moves forward as the pressure in the rear hydraulic chamber 6 increases, generates hydraulic pressure in the front hydraulic chamber, and supplies this to the corresponding brake hydraulic circuit. Furthermore, when the piston 4 retreats, the oil in the front oil reservoir 21 is replenished into the front hydraulic chamber, and the mechanism for generating oil pressure and the oil replenishment mechanism are substantially the same as those on the rear hydraulic chamber 6 side. Therefore, detailed explanation thereof will be omitted.

As clearly shown in FIG. 2, the front end of the booster cylinder 16 of the hydraulic booster B is fitted to the rear end of the cylinder body 1 of the mask cylinder M with the annular body 15 in between, and the cylinder body 1 and the booster cylinder 16 are They are fastened together by bolts 17.

Here, the small diameter hole 3a of the cylinder hole 3 of the mask cylinder M
The diameter of the large diameter hole 3b is D1, the diameter of the large diameter hole 3b is D2, and the annular body 15
The inner diameter of the booster cylinder 16 is D3, and the cylinder hole 18 of the booster cylinder 16 is
Assuming that the diameter of is D4, these dimensions are set in the following relationship.

Dl<D3<D4<D2 The booster piston 19 has a small diameter piston part 19α at the front, a large diameter piston part 19h at the rear, and a large diameter piston part 19.
The small diameter piston portion 19.b consists of a rond portion 19C protruding from the rear end surface of the piston portion 19. The Z and large diameter piston portion 195 are connected to the annular body 15 and the cylinder hole 18 of the booster cylinder 16.
The rond portion 19C penetrates the rear end wall of the booster cylinder 16 in an oil-tight manner and projects to the outside. In order to define the retraction limit of the booster piston 19, a stepped portion 1 capable of supporting the rear end surface of the large diameter piston portion 19b is provided.
8α is formed at the rear end of the cylinder hole 18.

The annular body 15 supports the rear end of the rear master piston 5 on its front end surface and defines its retraction limit. Further, in the cylinder hole 18, the annular body 15 and the large diameter piston portion 19b define an input hydraulic chamber 20 therebetween, and the large diameter piston portion 19b and the rear end wall of the booster cylinder 16 define an output hydraulic chamber 21 therebetween. to be accomplished. This output hydraulic chamber 2
1 is naturally formed to have a larger pressure receiving area than the input hydraulic pressure chamber 20. Further, the large diameter piston portion 5h of the rear mask piston 5 of the mask cylinder M and the small diameter piston portion 19α of the booster piston 19 define an outlet chamber 22 therebetween.

The input hydraulic pressure chamber 20 is connected to the oil tank 2 by a supply oil passage 23, and a hydraulic pump 24 as a hydraulic pressure source for pumping the reservoir of the oil tank 2 to the input hydraulic chamber 20 is interposed in the oil passage 23. A pressure accumulator 25 is connected downstream of the pump 24 .

The booster piston 19 has a ball type first. Second inlet valve 26. ．． 262 and one spool type outlet valve 27 are arranged in parallel.

The first inlet valve 261 has an oil passage 28.21 communicating between the input and output hydraulic chambers 20.21. A cylindrical valve chamber 29° formed along the axial direction of the booster piston 19 and the valve chamber 29
．． A ball valve body 30° opens and closes the oil passage 281 in cooperation with a valve seat formed on the rear end wall, and the valve body 3
0. Valve spring 31. which biases the valve in the closing direction. , the ball valve body 30. resists the force of the valve spring 311. It has an operating rod 321 that can be opened, making it more normally closed. Operating rod 32. is fitted into the booster piston 19 so as to be slidable in its axial direction, and its rear end protrudes into the output hydraulic chamber 21 .

Second inlet valve 26. is arranged symmetrically with the first inlet valve 261 with respect to the axis of the sheath stabilizer 19, and its configuration is the same as the first inlet valve 261 except for the difference in length of the operating rods 32□ and 322. , in the figure, the first inlet valve 26.
The corresponding part has the same major sign and a minor sign 1 at the end.
．． Add ``.

Thus, the opening timing of the first inlet valve 261 is adjusted to the second inlet valve 26.
2, the actuation rod 3 of the first inlet valve 26
2. is formed to be longer than the operating rod of the second inlet valve 262 by 32 degrees, and when the valve is closed, the opposing gap L1 between the rear end of the operating rod 321 and the front surface of the interlocking ring 48, which will be described later, is interlocked with the rear end of the operating rod 322. Ring 4
8 is set smaller than the facing gap L2 with the front surface. That is, L
It is said to be 1-kuri.

The outlet valve 27 is composed of a valve cylinder 33 fitted to the booster piston 19 on the axis of the piston 19, and a valve piston 35 slidably engaged with the inner hole of the valve cylinder 33, that is, the valve hole 34. A brake pedal 3 is provided at the rear end of the piston 35.
An input rod 36 operated by 7 is connected.

The valve cylinder 33 has an outlet port 38 connected to the output hydraulic chamber 21, and the valve piston 35 has an annular groove 39 that blocks and communicates with the outlet port 38 according to its advance and retreat, and this annular groove 3.
The oil passage 40 is connected to the oil passage 9. This oil passage 40 is communicated with the outlet chamber 22 via an oil passage 41 formed in the booster piston 19, and the outlet chamber 22 is connected to a radial groove 42 (see FIG. 4) provided on the front end surface of the annular body 15. ), an annular oil passage 43 formed at the rear end of the cylinder body 1, and the oil passage 43
It is communicated with the oil tank 2 via a return oil passage 44 connected to the oil tank 2 .

In the output hydraulic chamber 21, a bottle 45 is fitted into the valve piston 35 perpendicularly to its axis. Both ends of this bottle 45 are connected to the valve cylinder 33 and the rod portion 1 of the booster piston 19.
The rod portions 9C pass through long axial holes 46 and 47 formed in the rod portion 19C, and protrude from the outer circumferential surface of the rod portion 19C, and the projecting ends 45α and 45α are formed in a truncated conical shape. This both side protruding end portions 45α.

45.2, as shown in FIG. 3, there is a connecting hole 49.2 of the two-piece interlocking ring 48 that is slidably engaged with the outer peripheral surface of the rod portion 19C.
49 is fitted, and in order to maintain the connection state between the pin 45 and the interlocking ring 48, a coil spring 5 is installed around the outer periphery of the interlocking ring 48.
0 is wound. Therefore, the interlocking ring 48 is connected to the valve piston 35.
In response to the advance of the two men, 0 valve 26. , 2B, operating rod 3
2. ．． 32□ is placed opposite the rear end to push it forward.

In order to define the retraction limit of the valve piston 35, a circlip 51 capable of supporting the rear end surface is engaged with the inner circumferential surface of the rod portion 19C, and a return spring 52 that urges the valve piston 35 in the retraction direction is connected to the rod. It is compressed between the portion 19C and the valve piston 35. This return spring 52 also has the function of maintaining the fixed position of the valve cylinder 33 to the booster piston 19.

Here, when the booster piston 19 and the valve piston 35 are at their respective backward limits, the forward stroke L3 of the valve piston 35 required to close the outlet valve 27 is equal to the forward stroke L3 of the valve piston 35 required to open the first inlet valve 26. It is set smaller than the forward stroke L1 of 35. That is, L3<Ll.

The booster piston 1g has a large diameter hole 53 that opens on its front surface, and a small diameter hole 54 that opens on the rear end wall of this large diameter hole 53.
A rubber elastic piston 55 and a pressure receiving piston 56 of the same diameter are formed in the large diameter hole 53 in order from the back thereof.
A recoil piston 57 is slid into the small diameter hole 54 and has both ends abutted against opposing surfaces of the valve piston 35 and the elastic piston 55.

An output rod 58 is integrally protruded from the front surface of the pressure receiving piston 56, and this output rod 58 deeply enters a recess 59 on the rear surface of the rear mask piston 5 and comes into contact with the piston 5, whereby the rear piston 5 and the booster piston 19 are arranged as close as possible.

The depth of the recess 59 is selected to be equal to or larger than the radius of the large diameter piston portion 5z of the rear mask piston 50. In this way, when the rear mask piston 5 is pushed by the output rod 5B, an interesting effect can be applied to the piston 5.

In the above, the pressure receiving piston 56, the elastic piston 55, and the reaction piston 51 constitute a reaction mechanism R that transmits the operational reaction force of the mask cylinder M to the valve piston 35.

Next, the operation of this embodiment will be explained.

In the inoperative state of the valve valve valve 37, the valve piston 35 is held at the retracting limit by the force of the return spring 52 together with the interlocking ring 48, as shown, and the annular groove 39 is located at the outlet, J-"-
) 38, the outlet valve 27 is in an open state, while the first and second inlet valves 261
-262, operating rod 32I.

32□ is released from the interlocking ring 4B, and the ball valve body 3
0. ．． Since 30° is seated on the valve seats of the valve chambers 29I and 292 with the blade of the valve spring 311.31□, both valves are in a closed state. Therefore, the input and output hydraulic chambers 20
．． Between 21 and 26, both people have 0 valves. .

262, and the output hydraulic chamber 21 is connected to the oil tank 2 via the outlet port 38, the annular groove 39, the oil passage 401, the outlet chamber 22, the radial groove 42, the annular oil passage 43, and the return oil passage 44. Since the mask pistons 4 and 5 communicate with each other and are at atmospheric pressure, the front and rear mask pistons 4 and 5 and the booster piston 19 are held at the retracting limit by the force of the return spring 12 of each mask piston.

Furthermore, in this case, hydraulic pressure from the hydraulic pump 24 or the pressure accumulator 25 is introduced into the input hydraulic chamber 20, and this hydraulic pressure acts on the front surface of the large diameter piston portion 116 of the booster piston 19. Piston 19 is held at the retraction limit.

Further, since the ball valve bodies 30s and 30z have high obstructing properties, leakage of pressure oil from the input hydraulic chamber 20 to the output hydraulic chamber 21 can be reliably prevented.

Now, when the brake pedal 3T is depressed to brake the automobile, the valve piston 35 and the interlocking ring 48 are pushed forward from the brake pedal 37 via the input rod 36, and the above-mentioned Ls<
First, the annular groove 39 is blocked from the outlet port 38 due to the relationship Ls and Lt<Lz, that is, the outlet valve ? 7 closes,
The interlocking ring 48 then contacts the rear end of the operating rod 321 of the first inlet valve 261 and pushes it forward, thereby causing the ball valve body 30. is separated from its valve seat, and then the interlocking ring 4
B contacts the rear end of the operating rod 322 of the second inlet valve 262 and pushes it forward, thereby separating the valve body 302 from its valve seat. Thus the first and second inlet valves 2
61.26□ are opened sequentially.

By the way, at the initial stage when the outlet valve 27 is closed and the first inlet valve 26° is opened, the output hydraulic pressure chamber 21 is disconnected from the oil tank 2, and the input hydraulic pressure chamber is input from the hydraulic pump 24 or the pressure accumulator 25. The hydraulic pressure introduced into the valve chamber 29. is supplied to the output hydraulic chamber 21 through both hydraulic chambers 2
0.21 is approximately the same pressure. Therefore, the second inlet valve 26 before opening. Now, ball valve body 30. so that it can receive approximately the same hydraulic pressure on both front and rear surfaces, and the closing force of the ball valve body 30 □ due to the hydraulic pressure of the input hydraulic chamber 20 is offset or canceled by the valve opening force due to the hydraulic pressure of the output hydraulic chamber 21. Significantly reduced ball valve body 30
Since the valve opening resistance of No. 2 is extremely small, when the interlocking ring 48 pushes the operating rod 32t in the next step, the ball valve body 302 essentially only resists the force of the valve spring 312.
can be opened easily.

Then, when both 0 valves 2L-262 open, both oil passages 28. ．． 28. Since the pressure oil in the input hydraulic chamber 20 is smoothly supplied to the output hydraulic chamber 21 through the hydraulic pressure, the booster piston 19 can be rapidly advanced using the hydraulic pressure.

The advancing booster piston 19 is moved to the rear via the reaction mechanism R and the output rod 58. advance. In this way, the mask cylinder M is actuated with a booster force.

While the booster piston 19 is pushing the rear mask piston 5, the pressure receiving piston 56 receives the operational reaction force of the mask cylinder M from the rear mask piston 5 and operates to compress the elastic piston 55, and the compression force is A part of the valve piston 35 passes through the reaction piston 57, and then to the input rod 3.
6 to the brake pedal 37, which allows the driver to sense the magnitude of the braking force. The boost ratio at this time is that the cross-sectional area of the pressure receiving piston 56 is S8, the cross-sectional area of the reaction piston 57 is 5°, and in the illustrated example, the first and second inlet valves 26. ．． 26□ ball valve body 3
0□, 302 are formed to have the same diameter, but the first inlet valve 26. In order to minimize the opening resistance of the ball valve body 30. It is also effective to form the ball valve body 302 with a small diameter and to make the ball valve body 302 a large diameter in order to minimize the flow resistance.It is also effective to further increase the number of inlet valves and open them one after another. It is also effective to let the

C0 Effects of the Invention As described above, according to the present invention, at least two inlet valves are inserted in parallel and interposed in the oil passage between the output hydraulic chambers, and the opening timings of the inlet valves are staggered from each other. Therefore, the valve opening resistance due to the input oil pressure is caused by the early valve opening time, and only one inlet valve acts. The valve can be opened with a small input.

Moreover, by arranging a plurality of inlet valves in parallel, it is possible to significantly reduce the flow path resistance between the input and output hydraulic chambers, and as a result, both the operability and operational response of the single booster are improved. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view showing a uniform embodiment of the present invention, Fig. 2 is an enlarged view of its main parts, Fig. 3 is an enlarged sectional view taken along the line ■-■ of Fig. 1, and Fig. 4 is a 1 is a sectional view taken along the line ■-■ in FIG. B... Booster, M... Master cylinder, R...
Recoil mechanism 2...Oil tank, 16...Booster cylinder, 19...
・Booster piston, 20...Input hydraulic chamber, 21...
- Output hydraulic chamber, 22... Outlet chamber, 23... Supply oil path, 24... Hydraulic pump as a hydraulic pressure source, 25... Pressure accumulator, 26. . 262...1st. Second inlet valve, 27... Outlet valve, 2
81゜282...Oil passage, 29s=29g...Valve chamber,
3-01.

Claims (1)

[Claims] a booster cylinder; a booster piston that is slid into a cylinder hole of the booster cylinder and partitions its interior into a front input hydraulic chamber connected to a hydraulic pressure source; and a rear output hydraulic chamber having a larger pressure receiving area; The input rod is connected to the booster piston so that it can move forward and backward; it is interposed in the oil passage connecting the input and output hydraulic chambers, and is linked to the input rod so that it closes when the input rod retreats and opens when it moves forward. an inlet valve; an outlet valve that is interposed in the oil passage connecting the output hydraulic chamber and the oil tank and is linked to the input rod so that it opens when the input rod retreats and closes when the input rod moves forward; In a hydraulic booster in which valves are configured in a ball type, at least two of the inlet valves are input in parallel and interposed in an oil passage between the output hydraulic chambers, and the inlet valves are arranged in such a manner that their opening timings are adjusted. It is characterized by being linked to the input rod so that they are offset from each other.
Hydraulic booster.