JPH0224704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a master cylinder used in a brake system of an automobile, and more particularly to a tandem-type master cylinder equipped with a hydraulic pressure control valve.

(Prior Art) Conventionally, tandem-type master cylinders used in dual-system brakes for automobiles have been of the type that is integrally equipped with a hydraulic pressure control valve mechanism that controls the front and rear wheel brakes to a predetermined hydraulic pressure. Are known. To give an example, for example, a hydraulic control mechanism includes a stepped piston having a large diameter part and a small diameter part, and an actuator having a diameter smaller than the large diameter part of the stepped piston and larger than the small diameter part of the stepped piston. The pistons are slidably inserted in contact with each other to form a communication passage in the stepped piston that communicates one chamber of the master cylinder with the rear wheel brake side, and also to allow the stepped piston to slide. Accordingly, a valve is provided to open and close the communication passage, and one end of the stepped piston applies hydraulic pressure to the rear wheel brake and a biasing force by a spring, and one end of the operating piston applies hydraulic pressure to the front wheel brake. There is a device (for example, Japanese Unexamined Patent Publication No. 54-23876) that is configured to do so.

(Problem to be Solved by the Invention) However, in a master cylinder equipped with this type of hydraulic control valve, when the brake system fails due to breakage of the front brake system pipe, the operating piston Since the compensation function of the hydraulic pressure control valve was performed by hydraulic pressure control by reducing the force acting on the master cylinder to zero, a separate hydraulic circuit from the master cylinder and the hydraulic control valve was required, and the operation The size of the piston had to be increased due to the need for space to assemble the piston.

The present invention solves the above-mentioned problems, and its purpose is to provide a compact master cylinder with a hydraulic pressure control function.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a discharge port 2 of a tandem type master cylinder body 1.
A hydraulic pressure control valve 24 is connected to the hydraulic pressure control valve 2.
The valve body 35 of No. 4 is provided with an engaging portion 37 that protrudes toward the master cylinder body 1, and a slider 40 is provided between the valve body 35 and the master cylinder body 1.
is slidably arranged on the slider 40,
One end portion 43a applies rotational force to the engaging portion 37 as the slider 40 slides, and the other end portion 43b
is provided with a protrusion 43 that protrudes in the master cylinder body 1 through a slit 23 formed in the master cylinder body 1, and a pair of pistons 2 that are slidably inserted into the master cylinder body 1,
A valve actuation release member 6 is attached to one of the pistons 3 to engage with the other end 43b of the protrusion 43 and displace the other end 43b when the one piston moves by a predetermined stroke or more. It has a different configuration.

(Function) With the above-described configuration, when the pistons 2 and 3 in the master cylinder body 1 are displaced by a predetermined stroke or more due to failure of the brake system, the valve actuation release member 6 releases the hydraulic pressure control valve via the slider 40. 24 valve bodies 35 are removed from their seats, and the oil circuit of the hydraulic pressure control valve can be used to compensate for failures in the brake system.

Further, one end portion 43 of the protruding portion 43 of the slider 40
Since a acts on the engaging portion 37 of the valve body 35 at a location very close to the rotation fulcrum, the valve body 35 can be rotated by a certain rotation amount by a slight displacement of the slider 40. For this reason, the length of the slit 23 for ensuring the movement of the protrusion is extremely short compared to the case where the protrusion is formed integrally with the valve body and the valve body is tilted.

Furthermore, since the valve body 35 and the slider 40 are separate parts, only the slider 40 can be held by inserting its protrusion 43 into the slit 23 during assembly. Even if a bending force is applied to one end 43a, the slider 40
Since the plate surface receives the resistance force from the master cylinder main body 1, no bending force is applied to the other end 43b of the protrusion 43.

Furthermore, the valve body 3 and the slider 40 are separate parts, and the axial length of the protruding portion 43 is shortened by the amount that the engaging portion 37 is formed on the valve body 35.

(Example) An example of the present invention will be described below with reference to the drawings.

1 to 7, reference numeral 1 denotes a tandem-type master cylinder body having a cylindrical shape with a bottom, and a primary piston 2 is located on the opening side (right side in FIG. 1) in the master cylinder body 1, and A secondary piston 3 is slidably fitted into each of the pistons (left side in FIG. 1). A first pressurizing chamber 4 is formed between the primary piston 2 and the secondary piston 3,
A second pressurizing chamber 5 is formed between the secondary piston 3 and the bottom of the master cylinder body 1.
The first pressurizing chamber 4 communicates with a rear wheel brake system via a hydraulic pressure control valve 24, which will be described later, and the second pressurizing chamber 5 communicates with a front wheel brake system.

Primary piston 2 and secondary piston 3
A spring 7 is interposed between the secondary piston 3 and the primary piston 2, and the spring 7 presses and holds one end of a cylindrical member 6, which is a valve release member, on the end surface of the secondary piston 3 facing the primary piston 2. The cylindrical portion of the cylindrical member 6 is loosely fitted to the outer shape of the spring 7, and the other end is connected to the primary piston 2.
It extends towards the side. A flange portion 6a is formed on the outer peripheral edge of the other end of the cylindrical member 6, and the outer diameter of the flange portion 6a is expanded to near the inner peripheral surface of the master cylinder body 1. Further, a spring 8 is interposed between the secondary piston 3 and the bottom of the master cylinder body 1.

A first supply chamber 9 is formed between the outer periphery of the central part of the primary piston 2 and the master cylinder body 1.
Liquid-tightness is ensured by sealing materials 10 and 11 held on the outer circumferential surfaces of. Secondary piston 3
A second supply chamber 12 is formed between the outer periphery of the central part of the master cylinder body 1 and the second supply chamber 1.
2, liquid tightness is ensured by sealing materials 13 and 14 held on the outer peripheral surface of the secondary piston 3. The first replenishment chamber 9 communicates with the inside of the reservoir tank 16 in which oil is stored through a passage 15, and the second replenishment chamber 12 communicates with the inside of the reservoir tank 16 through a passage 17. Similarly, the first pressurizing chamber 4 and the second pressurizing chamber 5 also have passages 18 and 19, respectively.
communicated through.

In Fig. 2, S ₁ is the set stroke of the primary piston 2, S ₂ is the set stroke of the secondary piston 3, 20 is the stop bolt that restricts the movement of the secondary piston 3 toward the primary piston 2, and 21 is the master of the primary piston 2. This is a retaining ring that restricts movement outside the cylinder body 1.

A cylindrical discharge port 22 is provided in a protruding manner on the side wall of the master cylinder main body 1.
The inside communicates with the inside of the master cylinder body 1.
A hydraulic pressure control valve 24 is assembled to this discharge port 22. This hydraulic pressure control valve 24 will be explained with reference to FIG. 26 and an enlarged diameter section 27, and the housing 25 consists of a reduced diameter section 26 and an enlarged diameter section 27.
It is attached by screwing into the inner periphery of the discharge port 22. The inner circumferential side of the reduced diameter portion 26 is a stepped hole 28, and the stepped hole 28 includes a small diameter portion 28a, a medium diameter portion 28b, and
A large diameter portion 28c is formed. A cylindrical adapter 30 having a stepped hole 29 is screwed onto the inner periphery of the enlarged diameter portion 27 . part 29a, medium diameter part 29b, small diameter part 29c, threaded part 2
9d is formed, and the threaded portion 29d has a brake pipe (not shown) communicating with the rear wheel brake system.
is installed.

The middle diameter part 29b of the adapter 30 and the housing 25
A flanged operating piston 31 is slidably fitted into the small diameter portion 28a inside the reduced diameter portion 26, and the operating piston 31 is urged toward the adapter 30 by a return spring 32.
A valve seat 33 is formed on the end surface of the operating piston 31 on the master cylinder body 1 side.
The pressure receiving area of the side end face is set smaller than the pressure receiving area of the end face of the actuating piston 31 on the adapter 30 side. A communicating passage 34 is formed in the working piston 31. One end of this communicating passage 34 opens from the valve seat 33 into the inside of the reduced diameter portion 26, and the other end opens from the end surface of the working piston 31 on the adapter 30 side to the adapter 3.
0 is open inside.

Inside the reduced diameter portion 26 of the housing 25 is a valve body 3.
5 is placed. This valve body 35 has a disk shape, and a valve portion 36 corresponding to the valve seat 33 is formed in the center portion on one side of the valve body 35 . A cylindrical engagement portion 37 is formed on the other surface of the valve body 35 and is aligned with the axis of the valve body 35. It is located in The outer diameter of the valve body 35 is the middle diameter portion 28b.
and smaller than the diameter of the large diameter portion 28c, and the peripheral edge portion on one side of the valve body 35 can be seated and separated from the stepped portion 38 formed by the medium diameter portion 28b and the large diameter portion 28c. is biased by a spring 39. A through hole (not shown) is formed in the peripheral portion of the valve body 35, and when the peripheral portion of the valve body 3 is seated on the stepped portion 38, the diameter reducing portion 2 is formed through the through hole.
The inside of the medium diameter portion 28b and the inside of the large diameter portion 28c of No. 6 communicate with each other.

Inside the discharge port 22, a slider 40 is disposed between the tip of the reduced diameter portion 26 of the housing 25 and the master cylinder body 1. This slider 40
As shown in FIG. 4, it consists of a disc part 42 having a plurality of communication holes 41, and a shaft part 43 as a protruding part attached to the disc part 42 so as to extend in the axial direction of the disc part 42. . The disc portion 42 is slidable within the discharge port 22 along the inner bottom of the discharge port 22, and has a plurality of communication holes 41 in the disc portion 42.
The first pressurizing chamber 4 and the inside of the discharge port 22 are always in communication via the slit 23 and the slit 23. One end of the shaft portion 43 is spherical, and the spherical end 43 a faces into the cylindrical portion 37 of the valve body 35 . Shaft portion 43
The other end portion 43b projects into the first pressurizing chamber 4 through the slit 23, and the other end portion 43b of the shaft portion 43
faces the displacement movement region of the flange portion 6a of the cylinder member 6 when the front wheel brake system fails.

Next, the operation of the master cylinder will be explained.

(1) If both the front and rear brake systems are normal.

When the brake pedal is depressed and the primary piston 2 is pushed against the springs 7 and 8 toward the secondary piston 3 via a push rod (not shown), the oil in the first pressurizing chamber 4 and the second pressurizing chamber 5 is pressurized. The same liquid pressure is applied to both pressurized chambers 4 and 5.
_PM occurs.

In the initial stage (when the hydraulic pressure P _M is not applied), the valve seat 33 of the operating piston 31 is separated from the valve body 35 due to the urging force of the return spring 32, and the first pressurizing chamber 4 and the rear wheel brake are separated. It communicates with the system through the slit 23, the communication hole 41 of the slider 40, the through hole of the valve body 35, and the communication path 34. For this reason, the liquid pressure in the first pressurizing chamber 4
_PM is directly transmitted to the rear brake system.
In such a state, the force pushing the operating piston 31 due to the increase in the hydraulic pressure P _M overcomes the return spring 32 and the valve seat 3 of the operating piston 31
This continues until the valve body 35 is seated on the valve body 3. Point C in FIG. 5 indicates the point at which the valve body 35 is seated on the valve seat 33, and this point is called the cut point. After this cut point, the actuating piston 31 slightly reciprocates in the direction of the opening/closing valve in accordance with the increase in the hydraulic pressure in the first pressurizing chamber 4, and the valve body 35 repeats seating and separation from the valve seat 33. As shown in FIG. 5, the hydraulic pressure supplied from the first pressurizing chamber 4 to the rear wheel brake system rises slowly compared to the initial rise.

On the other hand, the hydraulic pressure _PM in the second pressurizing chamber 5 is transmitted to the front wheel brake system, and the same hydraulic pressure as the hydraulic pressure _PM in the second pressurizing chamber 5 is always transmitted to the front wheel brake system.

(2) When the rear wheel brake system is normal and the front wheel brake system has failed.

When the primary piston 2 is pushed toward the secondary piston 3 via the push rod against the springs 7 and 8, the secondary piston 3
It will be displaced until it comes into contact with the bottom of the master cylinder body 1, and will be displaced for a predetermined stroke or more. In conjunction with this, the flange portion 6a of the cylinder member 6 engages with the other end portion 43b of the shaft portion 43 of the slider 40, and the slider 40 slides together with the secondary piston 3 in the displacement direction of the secondary piston 3. As a result, the spherical end portion 43a of the shaft portion 43 comes into contact with the cylindrical engaging portion 37 of the valve body 35, and a rotational force centered on the step portion 38 is applied to the valve body 35, causing the valve body 35 to operate. The piston 31 is removed from the valve seat 33 (see FIG. 6). For this reason,
The first pressurizing chamber 4 and the rear wheel brake system are in communication, and the hydraulic pressure P _M in the first pressurizing chamber 4 is directly transmitted to the rear wheel brake system without causing a cut point. The hydraulic pressure P _M of No. 4 and the hydraulic pressure P _R of the rear wheel brake system are proportional from the beginning with a linear relationship of 45 degrees (see Figure 7).

(3) When the front wheel brake system is normal and the rear wheel brake system has failed.

When the primary piston 2 is pushed through the push rod, the primary piston 2 transmits its pushing force to the secondary piston 3, and a hydraulic pressure _PM is generated in the second pressurizing chamber 5. This hydraulic pressure P _M is directly transmitted to the front wheel brake system. The above is the operation of the master cylinder according to this embodiment.

By the way, in the configuration of this embodiment, in order to keep the valve body 35 always away from the valve seat 33 when the front wheel brake system fails, the shaft portion 43 of the slider 40 is attached to the cylindrical engagement portion 37 of the valve body 35. spherical end 43 of
a gives the stepped portion a rotational force about the fulcrum 38. At this time, the spherical end 43a engages the engaging portion 37 at a position extremely close to the stepped portion 38, which is the rotational fulcrum, to cause the slider 40 to slide. A force based on the displacement movement in the direction is applied, and the valve body 35 rotates extremely greatly based on the extremely small amount of slide of the slider 40. This can be easily understood by comparing this structure with the above-mentioned structure, although there is a structure in which the shaft portion 43 is integrally attached to the valve body 35. That is, in the latter case, since the distance from the rotational fulcrum to the point on which the force based on the displacement movement acts is smaller than in the former case, in order to rotate the valve body 35 by a certain amount using the stepped portion 38 as the fulcrum, In the latter case, it is sufficient to move the shaft portion 43 smaller than in the former case, and accordingly, in the latter case, the length of the slit 23 can be made smaller than in the former case. This means that it can be made shorter in the direction. Therefore, in the latter case, i.e.
In the present invention, since the length of the slit 23 can be extremely shortened, it is possible to prevent the sealing materials 10, 13 from moving due to sliding contact with the slit 23.
is no longer damaged by the periphery or edge forming the slit 23.

In addition, since the slider 40 is provided as a separate component to the valve body 35, and the slider 40 is composed of a disk portion 42 and a shaft portion 43, during assembly,
First, the slider 40 is held in the master cylinder body 1 by inserting its shaft portion 43 through the slit 23, and then the housing 25 incorporating the valve body 35 is screwed onto the master cylinder body 1. . That is, if the slider 40 is first held in the master cylinder body 1, even if a bending force is subsequently applied to the spherical end 43a, the disc part 42 will act as a drag force on the inner bottom of the discharge port 22. Receptacle, the other end 43b of the shaft portion 43
No force based on bending force acts on the Therefore, during assembly, breakage of the shaft portion 43 can be reliably prevented.

Furthermore, since the valve body 35 and the slider 40 are separate parts, the shaft portion 43 of the slider 40 that provides rotational force to the valve body 35 is such that the valve body 35 and the shaft portion 43 are integrally attached. The axial length of the shaft portion 43 can be made shorter than that of the conventional one, and the bending strength of the shaft portion 43 can be improved. Moreover, since the cylindrical engaging portion 37 is formed on the valve body 35, the joint between the valve body 35 and the engaging portion 37 is extremely strong, and the rotational force by the shaft portion 43 is transferred to the valve body 35.
will be reliably communicated.

FIGS. 8 and 9 show other embodiments, and the same components as those of the previous embodiment are given the same reference numerals and their explanations will be omitted.

This embodiment is an improvement of the slider 40, and the slider 40 is provided with a plurality of tongues 44 having spring properties on its peripheral edge. Due to the plurality of tongues 44, when the brake system is normal, the slider 4
0 is held so that its axis coincides with the axis of the housing 25, and when a failure occurs in the brake system, the slider 40 reliably rotates the valve body 35. Further, when the brake system returns to a normal state from a failure state, in addition to the force exerted by the spring 39, the force exerted by the tongue piece 44 acts as a multi-dimensional force, and the return to the original state is quickly performed.

Although the embodiments have been described above, the present invention includes the following aspects.

One front wheel cylinder is communicated with the first pressurizing chamber 4, and one rear wheel cylinder is communicated with the second pressurizing chamber 5 via the hydraulic pressure control valve 24, and the other front wheel cylinder is communicated with the second pressurizing chamber 5. At the same time, the present invention is applied to a so-called X-brake pipe that communicates with other rear wheel cylinders via the hydraulic pressure control 24.

The slider 40 according to another embodiment is molded from polypropylene resin or the like.

The shaft portion 43 of the slider according to each of the above embodiments is as follows:
Although the spherical end 43a at one end and the other end 43b are provided with their axes aligned, they may be provided with their respective axes shifted.

(Effects of the Invention) As described above, the present invention can compensate for failures in the brake system by using the oil circuit of the hydraulic pressure control valve, so there is no need to prepare a special oil circuit. , miniaturization can be achieved.

In addition, since the slit length can be made extremely short in the sliding direction of the slider, it is possible to prevent the sealing member attached to the outer circumferential surface of the piston in the master cylinder body from coming into sliding contact with the slit. Damage caused by the periphery forming the slit can be prevented.

Furthermore, during assembly, the plate surface of the slider receives the bending force that acts on one end of the protrusion, and the bending force does not reach the other end of the protrusion, improving the strength of the protrusion. This makes it possible to prevent the protrusion from breaking.

Furthermore, since the axial length of the protrusion of the slider can be shortened, the strength of the protrusion of the slider can also be improved from this point of view.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a master cylinder according to the present invention, FIG. 2 is a vertical cross-sectional view of FIG. 1, FIG.
The figure is a perspective view showing the slider according to the present invention, Figure 5 is a characteristic diagram of the hydraulic pressure control valve when the brake system is normal, Figure 6 is an operating state diagram of Figure 3, and Figure 7 is the front wheel brake system. A characteristic diagram of the hydraulic pressure control valve when it fails, FIG. 8 is an enlarged sectional view of the main part of a master cylinder according to another embodiment, and FIG. 9 is a perspective view of the slider used in FIG. 8. . DESCRIPTION OF SYMBOLS 1... Master cylinder main body, 2... Primary piston, 3... Secondary piston, 6... Cylinder material (valve operation release member), 23... Slit, 24
...Liquid pressure control valve, 35...Valve body, 37...Engaging part, 40...Slider, 43...Shaft part (protruding part),
43a...spherical end, 43b...other end.

Claims (1)

[Scope of Claims] 1. A hydraulic pressure control valve is connected to the discharge port of the tandem type master cylinder body, and the valve body of the hydraulic pressure control valve is provided with an engaging portion that protrudes toward the master cylinder body, and the A slider is slidably disposed between the valve body and the master cylinder body, and one end of the slider applies rotational force to the engaging portion according to the slide of the slider, and the other end applies rotational force to the master cylinder according to the slide of the slider. A protrusion is provided in the cylinder body that protrudes through a slit formed in the master cylinder body, and one of the pistons is slidably inserted into the master cylinder body. When the displacement exceeds the specified stroke,
A master cylinder characterized in that a valve actuation release member is attached that engages with the other end of the protrusion and displaces the other end. 2. A cylindrical housing of a hydraulic pressure control valve is screwed onto the inner periphery of a cylindrical discharge port formed in the master cylinder body, and a slider is disposed between the inner bottom of the discharge port and the tip of the housing. Claim 1
Master cylinder as described in section. 3. The master cylinder according to claim 1, wherein the slider is provided with a communication hole that communicates the slit with the hydraulic pressure control valve side. 4. The master cylinder according to claim 1, wherein a spring member is provided on the outer periphery of the slider for positioning the slider in the sliding direction and for returning the slider to its original position. 5. The master cylinder according to claim 4, wherein the spring member is a plurality of elastic tongues integrally formed on the peripheral edge of the plate-like portion constituting the slider.