JPH1199930A - Master cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master cylinder that is able to do any travel regulations surely by obviating the breakdown of an antislip member for slip-stop motion from the cylinder body opening side of a piston at the primary side by means of hydraulic pressure to be taken out of an external actuator. SOLUTION: An antislip member 50 is so constituted that an engaging part 50a to be engaged with a piston 34 capable of regulating any movement of this piston 34 to the side of a cylinder body owing part 32a, and a tubular part 50b to be screwed direct to a cylinder body 32 are integrally formed up, whereby any hydraulic pressure is made so as to be received by the cylinder body 32 at a time when the hydraulic pressure from an external actuator (pump unit) is taken into a hydraulic chamber 36. With this constitution, any fear of the antislip member 50 being broken down is eliminated and thus any possible slip-out motion of the piston 34 is surely obviable in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master cylinder used for a hydraulic brake system for a vehicle.

[0002]

2. Description of the Related Art For example, Japanese Patent Application No. 8-354052 previously proposed by the present applicant is known as this kind of prior art, and will be described below with reference to FIG.

[0003] A conventional master cylinder is generally designated by 1 and has a cylinder bore 3 formed in a cylinder body 2.
The first piston 4 on the primary side and the second piston 5 on the secondary side are slidably inserted into the first piston 4 and the second piston 5, respectively. A first hydraulic chamber 6 is defined between the first piston 4 and the second piston 5, and a second hydraulic chamber 7 is defined between the second piston 5 and the bottom of the cylinder hole 3. At the upper part of the cylinder body 2, a connection part 10 of a hydraulic fluid reservoir,
A first boss portion 8 and a second boss portion 9 into which the grommet seals 11 and 12 are fitted are formed. The first piston 4 and the second piston 5 are provided with center valve parts 14, 15, and as is well known, the piston 4,
The center valve portions 14 and 15 are opened and closed according to the movement of the fifth valve 5. The hydraulic pressure generated in the first and second hydraulic chambers 6 and 7 is supplied to the wheel cylinder of each wheel from an output port (not shown). A pipe 24 having a pump device 9 as an external actuator and a check valve 23 provided on the discharge side thereof is connected between the inside of the second boss portion 9 and the first hydraulic chamber 6. The pump device 22 is driven at the time of wheel drive slip or over-steering or under-steering at cornering, and the pump pressure is introduced into the first hydraulic chamber 6 to move the second piston 5 to the second hydraulic chamber 7 side. An automatic brake control system that obtains a predetermined braking force by moving is configured.

[0004] In the first piston 4, a pin member 16 which is a part of a component of the center valve portion 14 is supported by a cylindrical support member 17 mounted on the outer peripheral portion of the first piston 4. Is the opening 2 of the cylinder body 2
The movement to the opening 2a side is restricted by the annular ring 18 attached to a. That is, the movement of the first piston 4 on the side of the opening 2 a is restricted by the annular ring 18. Further, the annular ring 18 is mounted on the opening 2 a and is in annular contact with the outer periphery of the first piston 4 to guide the movement of the first piston 4 by an annular guide member 19.
The guide member 19 is supported by the opening 2.
It is positioned by the retaining ring 20 which is engaged with the annular groove 21 on the inner wall surface at the end of FIG.

[0005]

However, in the structure of the conventional master cylinder 1, the movement of the first piston 4 toward the cylinder body opening 2a is restricted, that is, the opening 2a is restricted.
The first ring 4 is prevented from coming off by the ring 20 which is engaged with the annular groove 21, so that the external device (pump device) 22 can be used during automatic brake control.
Is driven and hydraulic pressure is introduced into the first hydraulic chamber 6, there is a problem that the retaining ring 20 may be damaged without being able to withstand the large hydraulic pressure. The retaining ring 20 is made of a C-shaped ring member.
Even if the thickness in the axial direction is increased to increase the pressure resistance, the force required for elastic deformation (diameter reduction) is rather increased, and the assemblability of the cylinder body 2 to the opening 2a is deteriorated. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and prevents a retaining member that restricts movement of a primary-side piston from being damaged by hydraulic pressure from an external actuator (pump device), thereby reliably restricting movement. It is an object to provide a master cylinder capable of performing the above.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylinder body having an opening formed at one end and having a cylinder hole therein, and a hydraulic pressure slidably inserted into the cylinder hole. A piston for partitioning the chamber, a communication passage communicating between the hydraulic chamber and the reservoir and being opened / closed in accordance with the movement of the piston, a throttle hole formed in the communication passage, and the piston from the opening. Having a retaining member for preventing the liquid from coming off, and a master cylinder capable of introducing a hydraulic pressure generated by an external actuator into the hydraulic pressure chamber,
The retaining member includes an engagement portion that engages with the piston so as to restrict movement of the piston toward the opening, and a cylindrical portion that is directly screwed to the cylinder body on the opening side. The problem is solved by a master cylinder which is integrally formed.

According to the present invention, there is provided a retaining member for preventing a piston from coming off from an opening of a cylinder body, comprising: an engaging portion for engaging the piston so as to restrict movement of the piston toward the opening; By integrally forming the cylindrical portion directly screwed to the cylinder body on the side, the cylinder body receives the hydraulic pressure introduced from the external actuator into the hydraulic chamber. Thus, the possibility that the retaining member is damaged can be eliminated, and the piston can be reliably prevented from coming off from the opening.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a center valve type master cylinder according to an embodiment of the present invention, and shows only a peripheral portion of a first piston on a primary side. A piston (first piston) 34 having an annular seal member 35 mounted on its outer periphery is slidably inserted into a cylinder hole 33 formed inside the cylinder main body 32, and a front portion thereof (in the drawing) (Left side), a hydraulic chamber (first hydraulic chamber) 36 is defined. Recess 3 formed in the front part of piston 34
7, a valve chamber 39 is defined by a retainer 45 supporting one end of a return spring 44 fixedly screwed into the recess 37 and extended in the hydraulic chamber 36. The valve chamber 39 is made of rubber. And a valve seat supporting member 51 for supporting the valve seat 48
, A poppet valve element 47 and a valve spring 52 for urging the poppet valve element 47 toward the valve seat. The shaft portion of the poppet valve body 47 faces the inside of a long hole 64 formed on the body portion of the piston 34 in a direction perpendicular to the axial direction. In the illustrated state, a pin member penetrating the long hole 64 The valve is in an open state in contact with the valve.

The pin member 46 is supported by an annular collar member 54 slidably mounted on the outer periphery of the piston 34. The collar member 54 includes a collar 63 and a guide 55.
The both ends of the pin member 46 are supported by the guide 55, and the outer periphery thereof is covered with the side periphery of the collar 63. Therefore, in the present embodiment, as shown in FIGS. 2 and 3, semicircular notches 63a, 63a, 63a are formed on the side peripheral portion of the collar 63 as pin member insertion portions at positions other than on the same diameter of the collar 63. That is, the pin members 46 are prevented from coming off by being formed at intervals of, for example, 120 degrees (see FIG. 3). The collar 63 and the guide 55 can move relative to each other.
4. A spring member 53 whose one end is supported by the flange portion 34a
The collar 63 is moved against the spring force of the pin 55, and the semicircular pin member insertion portion 63a and the pin insertion portion (hole) of the guide 55 are moved.
And is aligned by Further, in the present embodiment, the pin member insertion portions 63a are formed at three locations at equal intervals, thereby improving the assemblability of the pin member 46.

A retaining member 50 according to the present invention is provided at an opening 32a of the cylinder body 32 via a seal ring 56. The retaining member 50 is an engagement portion 50a that can restrict the movement of the piston 34 toward the opening 32a.
And a tubular portion 50b which is screwed directly to the cylinder body 32 on the opening 32a side, and the engaging portion 50a and the tubular portion 50b are formed integrally. In the present embodiment, the engaging portion 50a can be engaged with the piston 34 via the guide 55 of the collar member 54 described above. An annular guide member 49 through which the piston 34 penetrates is housed on the inner periphery of the retaining member 50 via a seal ring 59, and the inner periphery of the guide member 49 is slidably contacted with the outer periphery of the piston 34. The movement of the piston 34 is guided.

A boss 38 formed on the upper part of the cylinder body 32 has one connecting portion 4 of a working fluid reservoir (not shown).
0 is fitted via a grommet seal 42 so that the inside of the working fluid reservoir (liquid storage chamber) can communicate with the hydraulic pressure chamber 36. That is, in the illustrated non-operating state of the brake, since the center valve mechanism is opened, the inside of the hydraulic fluid reservoir is provided around the shaft of the supply chamber 68, the long hole 64, the poppet valve body 47, the valve chamber 39, The hydraulic chamber 3 is connected via a communication passage formed of a throttle hole 45a formed in the retainer 45.
6, the center valve mechanism is closed by the movement of the piston 34 toward the hydraulic chamber 36, and the communication passage is shut off. Has become. Also, at the time of a predetermined automatic brake control performed at the time of wheel driving slip or over-steering or under-steering during cornering, the hydraulic fluid in the hydraulic fluid reservoir is pressurized by a pump device (not shown) which is an external actuator. It can be supplied to the chamber 36.

The opening 32a of the cylinder body 32 is connected to a negative pressure type brake booster 70 shown by a dashed line in the figure. At this time, the negative pressure type brake booster 7 is provided by the seal ring 66 attached to the outer periphery of the retaining member 50.
The space between the negative pressure chamber (not shown) and the atmosphere (outside) is sealed. Further, the guide member 4 is provided on the inner periphery of the retaining member 50.
9 is closed between the supply chamber 68 and the atmosphere by an annular first sealing member 57 mounted adjacent to the guide member 49, and a negative pressure type is provided by an annular second sealing member 58 mounted on the step portion of the guide member 49. The space between the negative pressure chamber of the brake booster 70 and the atmosphere is sealed. The space between the first and second sealing members 57 and 58 communicates with the outside via a through hole 71 formed in the guide member 49 and a through hole 72 formed in the retaining member 50. The positioning of the guide member 49 and the second sealing member 58 is performed by the annular member 61 and the ring member 62.

This embodiment is configured as described above.
Next, this operation will be described.

When the brake control by the driver's brake operation, that is, the manual brake control is performed from the inoperative state of the brake shown in the figure, the piston 34 is moved to the hydraulic pressure chamber 36 side. At this time, the collar member 54 supporting the pin member 46 is relatively moved with respect to the piston 34 by the urging force of the spring member 53 while the piston 34 moves a predetermined distance, and the poppet valve body 47 is securely moved to the valve seat 48. It is seated and brake fluid pressure is generated in the hydraulic chamber 36 as is known. In addition, the second piston (not shown) is also moved by the movement of the piston 34 to generate brake fluid pressure in the second fluid pressure chamber.

When the braking force is released by the driver releasing the brake operation, the spring force of the return spring 44 moves the piston 34 toward the supply chamber 68. At this time,
The collar member 54 comes into contact with the engaging portion 50 a of the retaining member 50, and then the shaft portion (end) of the poppet valve body 47 comes into contact with the pin member 46. As a result, the poppet valve element 47 is separated from the valve seat 48, and the center valve mechanism is opened. Also,
The movement of the piston 34 is restricted by abutting the peripheral wall of the elongated hole 64 with the pin member 46, and the guide 55 of the collar member 54.
This is performed by the engaging portion 50a of the retaining member 50 via.

At the time of wheel driving slip or over-steering or under-steering during cornering, the hydraulic chamber 3 is driven by a pump device (not shown) as an external actuator.
The brake fluid pressure is introduced into 6 and predetermined automatic brake control is performed. At this time, although the center valve mechanism of the piston 34 is in the valve open state, the inflow of the pump pressure introduced into the hydraulic pressure chamber 36 to the supply chamber 68 side is restricted by the throttle hole 45a. Two pistons are moved,
A brake hydraulic pressure is generated in the second hydraulic chamber.

During the automatic brake control, the piston 34 in the non-operating state shown in the drawing receives the hydraulic pressure introduced into the hydraulic chamber 36, that is, the discharge pressure of the pump device. At this time, the piston 34 is
The force acting on the side a is received, and the acting force is
The contact between the engaging portion 50a of the retaining member 50 and the guide 55 of the collar member 54 is performed through the contact between the peripheral wall portion and the pin member 46 as described above. Therefore, in the present embodiment, the retaining member 50 (more precisely, the cylindrical portion thereof)
Is directly screwed to the cylinder body 32, so that the contact force can be reliably supported. In other words,
The cylinder body 32 receives a large discharge pressure of the pump device acting on the piston 34 during the automatic brake control.

Therefore, according to the present embodiment, even during automatic brake control in which a large pump pressure acts on the piston 34, there is no possibility that the retaining member 50 will be damaged.
The removal of the piston 34 from the opening 32a of the cylinder body 32 can be reliably prevented, and the movement of the piston 34 can be reliably restricted.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.

For example, in the above embodiment, the piston 3
Although a center valve type master cylinder in which the valve body 47 is arranged on the central axis of the cylinder No. 4 is applied, instead of this, for example,
The present invention is also applicable to a conventional master cylinder that opens and closes a communication hole provided on the cylinder body side as the piston moves.

In the above embodiment, the annular collar member 54 for supporting both ends of the pin member 46, which is a component of the center valve mechanism, is composed of the collar 63 and the guide 55. It is also possible to constitute this with one member. Further, the pin member insertion portion 63a
Of course, it is also possible to increase or decrease the number.

[0024]

As described above, according to the master cylinder of the present invention, the retaining member for preventing the piston from coming off from the opening of the cylinder body can restrict the movement of the piston toward the opening. Since the engagement portion that engages with the piston and the cylindrical portion that is directly screwed to the cylinder body on the opening side are integrally formed, the hydraulic pressure introduced from the external actuator into the hydraulic pressure chamber is controlled by the cylinder. The stopper can be received by the main body, whereby the risk of the retaining member being damaged can be eliminated, and the piston can be reliably prevented from coming out of the opening.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a master cylinder according to an embodiment of the present invention.

FIG. 2 is a sectional view showing one component of a collar member according to the present invention.

FIG. 3 is a view in the direction of arrows [3]-[3] in FIG. 2;

FIG. 4 is a cross-sectional view showing the entirety of a conventional master cylinder.

DESCRIPTION OF SYMBOLS 32 Cylinder main body 32a Opening 33 Cylinder hole 34 Piston 36 Hydraulic chamber 45a Restriction hole 46 Pin member 49 Guide member 50 Retaining member 50a Engaging portion 50b Cylindrical portion 54 Collar member 63a Pin member inserting portion

Claims (5)

[Claims] A cylinder body having an opening at one end and having a cylinder hole therein; a piston slidably inserted into the cylinder hole to define a hydraulic chamber in the cylinder hole; A communication passage communicating between the pressure chamber and the reservoir and being opened / closed in accordance with the movement of the piston, a throttle hole formed in the communication passage, and a retaining member for preventing the piston from coming off from the opening; A master cylinder capable of introducing a hydraulic pressure generated by an external actuator into the hydraulic chamber, wherein the retaining member and the piston are capable of restricting movement of the piston toward the opening. A master cylinder, wherein an engaging portion to be engaged and a tubular portion directly screwed to the cylinder body at the opening side are integrally formed. 2. The guide member according to claim 1, wherein the piston penetrates the inner periphery of the retaining member and guides the movement of the piston by slidingly contacting the outer periphery of the piston. Master cylinder. 3. The master cylinder is a center valve type master cylinder, wherein a pin member which is a part of a component of the center valve penetrates through the piston in a direction orthogonal to an axis of the piston. The end of the pin member is supported by an annular collar member fitted on the outer periphery of the piston, and the engagement portion and the piston can be engaged via the collar member. The master cylinder according to claim 1 or 2, wherein: 4. A plurality of pin member insertion portions are formed on the annular collar member, and the pin member insertion portions are
The master cylinder according to claim 3, wherein the master cylinder is formed at a position other than the same diameter. 5. The master cylinder according to claim 4, wherein said pin member insertion portion is formed by a semicircular notch at one end side of said annular collar member.