JPH049699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Application Field The present invention relates to a master cylinder, particularly a cylinder body provided with an oil reservoir, a partition collar fitted into a cylinder hole of the cylinder body, A plunger is supported by a bulkhead collar so as to be slidable in the longitudinal direction and defines a hydraulic chamber in front of the bulkhead collar, a return spring biases the plunger in a backward direction, and a plunger is mounted on a cylinder body so as to face the hydraulic chamber. It consists of a one-way seal member that brings the inner lip into close contact with the outer peripheral surface of the plunger and the outer lip with the inner peripheral surface of the cylinder hole, and an annular spacer interposed between the one-way seal member and the partition collar. When the one-way seal member is at a predetermined retraction limit, a relief port that communicates with the hydraulic chamber is drilled immediately after the inner lip of the one-way seal member, and a relief port is provided between the relief port and the oil reservoir on the surface of the bulkhead collar facing the spacer. This invention relates to an improvement of a master cylinder in which radial grooves are formed to communicate with each other.

(2) Prior art This type of master cylinder is, for example,
This is already known as disclosed in Japanese Patent No. 151456.

(3) Problems to be solved by the invention In the conventional master cylinder, there is a gap between the outer circumferential surface of the spacer and the inner circumferential surface of the cylinder hole, so that a part of the rear outer circumferential edge of the one-way seal member There is a risk that the one-way seal member may bulge out from the gap and bite into the radial groove, resulting in damage to the one-way seal member.

An object of the present invention is to provide the master cylinder that can prevent such inconveniences.

B. Structure of the Invention (1) Means for Solving the Problems The present invention provides a structure in which, between the spacer and the partition wall collar,
An elastic ring is interposed between the opposing surfaces of a pair of opposing free ends using its own diameter reducing force, and the elastic ring expands in diameter while sliding on the opposing surfaces due to increased pressure in the hydraulic chamber. It is characterized in that both free ends are shifted in the axial direction from each other in a free state, and both opposing surfaces are inclined in the axial direction so that the inner peripheral surface of the cylinder hole is brought into close contact with the inner circumferential surface of the cylinder hole.

(2) Effect According to the above configuration, even if a part of the rear outer circumferential edge of the one-way seal member bulges out from the gap between the outer circumferential surface of the spacer and the inner circumferential surface of the cylinder hole as the pressure in the hydraulic chamber increases, the bulged portion The durability of the one-way seal member can be improved by preventing the elastic ring from digging into the radial groove.

In addition, as the pressure in the hydraulic chamber decreases, the diameter of the elastic ring decreases, forming a gap between its outer circumferential surface and the inner circumferential surface of the cylinder hole, and this gap functions as a passage for supplying hydraulic oil to the hydraulic chamber. Hydraulic oil replenishment efficiency can be improved.

(3) Embodiment In Fig. 1, M is a tandem type master cylinder for a two-system hydraulic brake of an automobile, and its cylinder body 1 is mounted in front of a booster shell 2 of a negative pressure booster B supported by a vehicle body (not shown). The rear end is fixed.

An auxiliary oil reservoir 3 is integrally provided on the upper side of the cylinder body 1, and a main oil reservoir 4 is connected thereto. The main oil reservoir 4 has a cap 5 at its upper end, and a known oil level sensor 6 supported by the cap 5 inside.
It is equipped with

The inside of the auxiliary oil reservoir 3 is divided by a partition wall 7 into first and second oil reservoirs 8 ₁ and 8 ₂ , and these oil reservoirs 8 ₁ ,
8 ₂ are each supplied with hydraulic oil from the main oil reservoir 4.

The first and second oil reservoirs 8 ₁ and 8 ₂ each have a through hole 9
₁ and 9 ₂ to communicate with the stepped hole 10 of the cylinder body 1. The stepped hole 10 is a first hole 1 whose front end is closed.
0a, a second hole 10b having a larger diameter than the first hole 10a and continuous to the rear end, and a third hole 10c having a larger diameter than the second hole 10b and continuous to the rear end and having an open rear end. A sleeve 13 forming a part of the cylinder body 1 is fitted into the cylinder body 10c, so that the first hole 10a, the second hole 10b and the through hole 13c of the sleeve 13 form a cylinder hole H. The large diameter front part a of the front partition collar 12 ₁ is fitted into the second hole 10 b, and the sleeve 13 abuts the rear surface of the flange part c between the large diameter front part a and the small diameter rear part b of this collar 12 ₁ . Further, the small diameter rear portion b is fitted into the front end portion of the through hole 13c of the sleeve 13. A rear bulkhead collar 1 is attached to the rear end of the through hole 13c of the sleeve 13.
The large diameter front part a of the collar ₁₂₂ is fitted, and the bearing 14 disposed in the third hole 10c is in contact with the rear surface of the flange part c between the large diameter front part a and the small diameter _rear part b of the collar 122. The small diameter rear portion b is fitted into the recess 15 of the bearing 14. The mounting structure of the bearing 14 to the cylinder body 1 will be described later.

A front annular oil chamber 11 ₁ connected to the front passage hole 9 ₁ is defined between the outer peripheral surface of the flange portion c of the front partition collar 12 ₁ and the inner peripheral surface of the third hole 10 c. Also, the outer circumferential surface of the flange c of the rear bulkhead collar 12 ₂ and the third
Rear annular oil chamber 11 defined between the inner peripheral surfaces of the hole 10c
₂ communicates with the rear through hole 9 ₂ via an axial groove 13 a and an annular groove 13 b running on the outer peripheral surface of the sleeve 13 .

A pair of front and rear plungers 16 ₁ and 16 ₂ are fitted in the front part of the front partition collar 12 ₁ and the through hole 13c of the sleeve 13, and in the rear part of the through hole 13c of the rear partition collar 12 ₂ and the sleeve 13, respectively, so as to be slidable in the front and rear directions. and front plunger 16 ₁
and the front hydraulic chamber 17 between the front end wall of the first hole 10a.
₁ is defined, and a rear hydraulic chamber 17 ₂ is defined between both plungers 16 ₁ and 16 ₂ . These hydraulic chambers 17 ₁ and 17 ₂ communicate with two brake hydraulic circuits via front and rear output ports 18 ₁ and 18 ₂ of the cylinder body 1.

The rear end of the rear plunger 16 ₂ passes through a bearing 14 that slidably supports the outer peripheral surface of the rear plunger 16 2 , extends to the rear of the cylinder body 1 , and further penetrates the front wall of the booster shell 2 to receive the output of the negative pressure booster B. Connect to rod 19.

In order to prevent negative pressure inside the booster shell ₂ from leaking from the through hole 20 of the booster shell 2 through which the rear plunger 16 2 passes, a sealing member 21 whose lip is brought into close contact with the outer peripheral surface of the rear plunger 16 ₂ is installed in the cylinder body 1 . and the booster shell 2.

As clearly shown in Figures 1 and 8, the rear hydraulic chamber 1
7 ₂ and the rear output port 18 ₂ , the sleeve 13 has a plurality of axial grooves 23 ₁ and 23 ₂ of two types long and short running on its inner circumference, a horizontal hole 24, and a plurality of axial grooves 23 2 running on its outer circumference. An annular groove 25 is provided. The rear plunger 16 ₂ is provided with a bottomed spring holding hole 31 ₂ that opens on its front end surface, and a rear return spring 30 ₂ that biases the plunger 16 ₂ in the backward direction is housed in the hole 31 ₂ . Further, a bolt 32 that projects a certain length in the axial direction from the end wall of the spring holding hole 31 ₂ is screwed onto the rear plunger 16 ₂ , and a hat-shaped spring that supports the front end of the rear return spring 30 ₂ is attached to the bolt 32 . The holding cylinder 33 is slidably connected within a certain stroke range.

The flange portion 33a of the spring holding cylinder 33 is provided with a plurality of protrusions p projecting in the radial direction, and each protrusion p is engaged with a short axial groove 23 ₁ of the sleeve 13.
The rear end of the axial groove 23 ₁ is closed by a stopper wall 29 integrated with the sleeve 13 , and when the projection p comes into contact with this stopper wall 29 , a predetermined retraction limit of the rear plunger 16 ₂ is determined. .

As clearly shown in FIGS. 2 to 4 and 8, a plurality of notches n are provided in the flange portion c of the front partition wall collar ₁₂₁ .
are formed at equal intervals on the circumference. Further, a plurality of radial grooves 34 ₁ are formed on the front surface of the large diameter front part a so as to cut into each notch part n, and each groove 34 ₄ connects to the front annular oil chamber 11 ₁ through each notch part n. communicate. From these radial grooves 34 ₂ to the long axial grooves 2 of the sleeve 13
A rear one-way seal member 35 ₂ that allows hydraulic oil to flow only to the rear plunger 16 ₂ has an inner lip l ₁ on the outer peripheral surface of the rear plunger 16 ₂ and an outer lip l ₂ on the back of the through hole 13 c of the sleeve 13 . They are attached to the sleeve 13 in close contact with the inner peripheral surfaces of the ends.

Further, at the rear end of the through hole 13c of the sleeve 13, there is a retainer _{362 that holds the front end of the rear one-way seal member 352 ,} and an annular retainer 362 that is interposed between the rear one-way seal member ₃₅₂ and the rear partition wall collar _122. A spacer 37 ₂ is attached.

At the large diameter front part a of the rear bulkhead collar 12 ₂ ,
An annular convex part f is formed on the inner peripheral part of the front end surface, and an elastic ring 22 shown in FIG. 5 is attached to the annular convex part f.
₂ is loosely fitted, whereby the elastic ring 22 ₂ is interposed between the spacer 37 ₂ and the rear bulkhead collar 12 ₂ .

The elastic ring 22 ₂ has a pair of opposing free ends 22 c and 22 d facing each other due to its own diameter reducing force.
a, 22b are abutted against each other, and both opposing surfaces 22a,
22b is inclined upward in the axial direction, thus from the front side to the rear side. Also, in a free state,
The acute angle part g of one free end 22c is the same as that of the other free end 22c.
2d is offset by ε in the axial direction, and hence forward, from the acute angle h, and thereby both free ends 22
c and 22d are shifted from each other in the axial direction. When the elastic ring 22 is in a free state, a gap is formed between its outer peripheral surface and the inner peripheral surface of the through hole 13c.

A rear relief port 38 ₂ is bored in the rear plunger 16 2 that communicates between the radial groove 34 ₂ and the spring retaining hole 31 ₂ immediately after the rear one-way seal member 35 ₂ when the rear plunger 16 ₂ is at a predetermined retraction limit. .

In addition, the rear plunger 1 is located in the recess 15 of the bearing 14.
6 Seal member 3 that brings the lip into close contact with the outer peripheral surface of ₂
9 ₂ is installed.

On the other hand, the front plunger 16 ₁ is provided with a bottomed spring holding hole 31 ₁ that opens on its front end surface, and a front return spring 30 _{1 is inserted into the hole 31 1} to bias the front plunger 16 ₁ in the backward _direction . is accommodated. The predetermined retraction limit of the front plunger 16 ₁ is determined by the rear end abutting against the flange portion 33 a of the spring retaining cylinder 33 that abuts against the stopper wall 29 .

The spring retaining hole 31 ₁ of the front plunger 16 ₁ is arranged so that the front return spring 30 ₁ can be reliably accommodated in its entirety when the plunger 16 ₁ advances until it abuts the front end wall of the first hole 10a. Majority part 31a
is enlarged. Such expansion may be stepped or tapered as shown in FIG.

Similar to the rear partition collar 12 ₂ , a plurality of notches n are formed at equal intervals on the circumference in the flange c of the front partition collar 12 ₁ . In addition, a plurality of radial grooves 34 are formed on the front surface of the large diameter front part a so as to cut into each notch part n.
₁ is formed, and each groove 34 ₁ communicates with the front annular oil chamber 11 ₁ via each notch n. The front one-way seal member 35 ₁ , which only allows the flow of hydraulic oil from these radial grooves 34 ₁ to the front hydraulic chamber 17 ₁ , has its inner lip l ₁ on the outer peripheral surface of the front plunger 16 ₁ .
Further, the outer circumferential lip _l2 is attached to the second hole 10b by bringing it into close contact with the inner circumferential surface of the second hole 10b.

A front one-way seal member 35 is provided in the second hole 10b.
An annular spacer 37 ₁ is installed between the retainer 36 ₁ that holds the front end of the retainer 36 ₁ and the seal member 35 ₁ and the front partition collar 12 ₁ .

As above, the large diameter front part a of the front partition collar 12 ₁
An annular convex portion f is formed on the inner periphery of the front end surface, and an elastic ring 22 ₁ having the same structure as the elastic ring 22 ₂ shown in FIG. 22 ₁ is spacer 37 ₁
and the front bulkhead collar 12 ₁ .

When the front plunger 16 ₁ is at a predetermined retraction limit, a front relief port 38 _{1 is bored immediately after the front one-way seal member 35 1} and communicates between the radial groove 34 ₁ and the spring retaining hole _{31 1.} will be established.

In addition, at the front end of the through hole 13c of the sleeve 13,
A sealing member 39 ₁ is attached to the outer peripheral surface of the front plunger 16 ₁ to bring the lip into close contact with the outer circumferential surface of the front plunger 16 1 .

Here, the radial inner end d of each radial groove 34 ₁ , 34 ₂ in the front and rear partition collars 12 ₁ , 12 ₂
As shown in FIGS. 2 to 4, each spacer 3
It ends at a position radially outward from the inner circumferential edge e of 7 ₁ and 37 ₂ .

Next, the cylinder body 1 is shown in FIGS.
The mounting structure of the bearing 14 will be explained.

In the cylinder body 1, the rear end opening of the third hole 10c is formed as a large-diameter annular step 40, and the step 40 has a plurality of inward protrusions 41 extending radially inward at the rear end edge of the step 40. Formed at even intervals. The tip end surface of each inward protrusion 41 is located on the extended inner peripheral surface of the third hole 10c.

The bearing 14 consists of a cylindrical portion 42 that supports the rear plunger 16 ₂ and a plurality of outward protrusions 43 formed at the rear end and directed radially outward, each outward protrusion 43 facing inwardly. It is designed so that it can be loosely inserted into a notch 46 between the protrusions 41.

The cylindrical portion 42 of the bearing 14 is rotatably fitted into the third hole 10c together with a ring-shaped seal member 45 attached to an annular groove 44 on the outer circumferential surface of the cylindrical portion 42, and at this time, each outward protrusion 43 is inserted into each notch. It passes through section 46. When the bearing 14 is rotated around the axis of the third hole 10c by engaging a tool with the pair of engagement holes 47 opened on the rear end surface, each outward protrusion 43 engages with the front surface of each inward protrusion 41. do.

The bearing 14 is prevented from rotating by a stop spring 48, which is connected to the opposing piece 4.
A U-shaped portion 49 that urges 9a and 49b in a direction to separate them from each other, and an engagement piece that is connected to the tip of each opposing piece 49a and 49b and bent at an acute angle to the outside of each opposing piece 49a and 49b. It consists of 50a and 50b. The U-shaped portion 49 is attached to one notch portion 46 by bending both opposing pieces 49a and 49b in a direction toward each other, and the tips of both engaging pieces 49a and 49b are bent outward toward each other. The protrusions 43 are engaged with the opposing surfaces and the front surfaces of the adjacent inward protrusions 41, respectively. This engagement prevents the stop spring 48 from falling off from the notch 46 and also prevents the bearing 14 from rotating.

Next, the operation of this embodiment will be explained.

Now, operate negative pressure booster B and increase its output rod 1.
9 is pushed forward, both plungers 16 ₁ and 16 ₂ are pressed by the corresponding return springs 30.
It moves forward while compressing _{1,30 2} . in this case,
Since the cylindrical portion 42 of the bearing 14 is fitted into the third hole 10c, the coaxiality of the bearing 14 with respect to the sleeve 13 is easily ensured in terms of processing accuracy, and therefore the sliding movement of the rear plunger 16 ₂ is easily ensured. can be carried out smoothly.

Then, when the front relief port 38 ₁ moves to the front of the front one-way seal member 35 ₁ , the front hydraulic chamber 17 ₁ responds to the forward force of the front plunger 16 ₁ .
Hydraulic pressure is generated at the rear relief port 38 ₂
When the rear one-way seal member 35 ₂ moves forward, hydraulic pressure is generated in the rear hydraulic chamber 17 ₂ in response to the forward force of the rear plunger 16 ₂ .

The hydraulic pressure generated in the front and rear hydraulic chambers 17 ₁ , 17 ₂ is transferred to the corresponding output ports 18 ₁ , 18 _{2 .}
It is possible to simultaneously operate two hydraulic brake systems and apply braking to a car.

During this braking, as the pressure in the front and rear hydraulic chambers 17 ₁ and 17 ₂ increases, the front and rear one-way seal members 35 ₁ and 35 ₂
is the elastic ring 22 via the spacers 37 ₁ and 37 _2
1 and 22 ₂ are pressed against the front and rear bulkhead collars 12 ₁ and 12 ₂ , the elastic rings 22 ₁ and 22 ₂ expand in diameter while sliding on both opposing surfaces 22a and 22b, as shown by the chain lines in FIG. the outer peripheral surface of the second hole 10b and the through hole 1.
3c, so that a part of the rear outer periphery of the front and rear one-way seal members 35 ₁ , 35 ₂ is in contact with the outer periphery of the spacers 37 ₁ , 37 ₂ and the second hole 10 b.
Even if the through hole 13c bulges out from the gap between the inner peripheral surfaces, the bulged portion can be prevented from digging into the radial grooves 34 ₁ and 34 ₂ .

Furthermore, even if the rear inner peripheral edges of the front and rear one-way seal members 35 ₁ and 35 ₂ bulge out from the gap between the outer peripheral surfaces of the front and rear plungers 16 ₁ and 16 ₂ and the inner peripheral surfaces of the spacers 37 ₁ and 37 ₂ , each radial Since the inner ends d of the grooves 34 ₁ , 34 ₂ are located radially outward than the inner circumferential edges e of the spacers 37 ₁ , 37 ₂ , the bulging portions of the grooves 34 ₁ , 34 2 cut into the radial grooves 34 1 , 34 ₂ . It doesn't get too crowded.

In this way, the front and rear one-way seal members 35 ₁ ,
35 Each radial groove 34 on the rear inner and outer peripheral edges in ₂
By preventing digging into the seal members ₁ and 34 ₂ , the durability of these seal members 35 ₁ and 35 ₂ can be improved. Further, by preventing the rear inner peripheral edges of the front and rear one-way seal members 35 ₁ and 35 ₂ from digging in, the front and rear plungers 16 ₁ and 16 ₂ can be smoothly advanced and retreated.

When the negative pressure booster B is returned to the inoperative state in order to release the brake, each plunger 16 ₁ , 16 ₂ is returned to a predetermined retraction limit by the repulsive force of the corresponding return spring 30 ₁ , 30 ₂ , but after that, If the pressure in each hydraulic chamber 17 ₁ , 17 ₂ is reduced during the retraction process, the outer periphery lip l ₁ , l ₂ of the corresponding one-way seal member 35 ₁ , 35 ₂ increases.
The pressure difference between the front and rear causes the hydraulic chambers 17 ₁ and 1 to open, respectively.
7 ₂ side, the hydraulic oil in the first oil reservoir chamber 8 ₁ flows into the inner circumferential lip of the through hole 9 ₁ , the front annular oil chamber 11 ₁ , the radial groove 34 ₁ and the front one-way seal member 35 ₁ . l ₁ is supplied to the front hydraulic chamber 17 ₁ , and the hydraulic oil in the second oil reservoir 8 ₂ is supplied to the through hole 9 ₂ , the rear annular oil chamber 11 ₂ , the radial groove 34 ₂ , and the rear one-way seal member 3
5 Inner circumference lip of ₂ l Inner side of ₁ and long axial groove 2
The rear hydraulic chamber 17 ₂ is supplied through 3 ₂ .

At the same time, as the pressure in the front and rear hydraulic chambers 17 ₁ , 17 ₂ decreases, the elastic rings 22 ₁ , 22 ₂ contract in diameter while sliding on both opposing surfaces 22 a, 22 b by their own diameter reducing force, and the elastic rings 22 ₁ , 22 ₂ outer peripheral surface and second hole 10
b _{. A} gap is formed between the inner circumferential surfaces of the through holes 13c _, and _{the front} , Rear hydraulic chamber 17 ₁ , 1
Hydraulic oil is replenished on 7 ₂ .

This makes it possible to improve the efficiency of replenishing hydraulic oil.

When the respective hydraulic oil chambers 17 ₁ , 17 ₂ are overfilled with hydraulic oil during the replenishment process, the excess amount is absorbed into the respective relief ports 38 ₁ , 38 when the respective plungers 16 ₁ , 16 ₂ return to the retraction limit. ₂ to the oil sump 8 ₁ and 8 ₂ side.

For maintenance of master cylinder M,
By removing the stop spring 48 and then rotating the bearing 14 so that the inward projections 41 and the outward projections 43 are aligned, the bearing 14 can be removed from the cylinder body 1, and the bearing 14 can also be installed. Since it is easy, the workability is good.

C. Effects of the Invention According to the present invention, by interposing the elastic ring having a specific structure as described above between the spacer and the partition wall collar, the one-way seal member is prevented from digging into the radial groove, and its durability is improved. In addition, the efficiency of replenishing hydraulic oil to the hydraulic chamber can be improved.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional side view of a tandem type master cylinder, and FIG.
The figure is a partially enlarged view of Figure 1, and Figure 3 is Figure 1-
4 is a partial perspective view of the rear bulkhead collar, FIG. 5 is a side view of the elastic ring, and FIG. 6 is a partial perspective view of the rear bulkhead collar.
7 is a sectional view taken along the line shown in FIG. 6, and FIG. 8 is an exploded perspective view of the main parts. H...Cylinder hole, M...Tandem type master cylinder, _l1 , _l2 ...Inner, outer lip, ε...Amount of deviation, 1...Cylinder body, ₈₁ , ₈₂ ...1st, 2nd Oil sump, 16 ₁ , 16 ₂ ... front, rear plunger,
17 ₁ , 17 ₂ ...Front, rear hydraulic chamber, 22 ₁ , 22 ₂
...Elastic ring, 22a, 22b...Opposing surface, 2
2c, 22d...free end, 30 ₁ , 30 ₂ ...front,
Rear return spring, 35 ₁ , 35 ₂ ... front, rear one-way seal member, 38 ₁ , 38 ₂ ... front, rear relief port.

Claims (1)

[Claims] 1 A cylinder body equipped with an oil reservoir, a partition collar fitted into a cylinder hole of the cylinder body, and a plunger supported by the partition collar so as to be slidable in the front and rear direction and defining a hydraulic chamber in front of the partition collar. a return spring that biases the plunger in the backward direction; and a return spring that is attached to the cylinder body so as to face the hydraulic chamber and has an inner circumferential lip on the outer circumferential surface of the plunger and an outer circumferential lip on the inner circumferential surface of the cylinder hole. and an annular spacer interposed between the one-way seal member and the partition wall collar, and the one-way seal member is provided with the one-way seal member when the plunger is at a predetermined retraction limit. In a master cylinder, a relief port communicating with the hydraulic chamber is bored immediately after the inner peripheral lip, and a radial groove communicating between the relief port and the oil reservoir is formed on a surface of the partition collar facing the spacer. , an elastic ring is interposed between the spacer and the partition wall collar, and the elastic ring has its own diameter reducing force abutting the opposing surfaces of the pair of opposing free ends, and the elastic ring is able to compress both sides by increasing the pressure of the hydraulic chamber. Both free ends are shifted in the axial direction from each other in a free state, and both opposing surfaces are tilted in the axial direction so that the diameter of the opposing surfaces is expanded while sliding and the outer circumferential surface is brought into close contact with the inner circumferential surface of the cylinder hole. A master cylinder characterized by: