JPH049698B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Industrial Field of Application The present invention provides a cylinder body provided with first and second oil reservoirs, a sleeve fitted into a cylinder hole of the cylinder body, and a sleeve fitted into a cylinder hole of the cylinder body. a front plunger slidably fitted within the sleeve to define a front hydraulic chamber between the sleeve and the front end wall of the cylinder bore; and a rear hydraulic chamber defined between the front plunger and the front plunger. A rear plunger that is slidably fitted into the sleeve, a front return spring that biases the front plunger in the backward direction, a rear return spring that biases the rear plunger in the backward direction, and a rear plunger that is attached to the cylinder hole. a front one-way seal member that is attached to the sleeve and brings the lip into close contact with the outer peripheral surface of the front plunger; a rear one-way seal member that is attached to the sleeve and brings the lip into close contact with the outer peripheral surface of the rear plunger; and a bearing attached to the cylinder body to slidably support the outer peripheral surface of the rear plunger.The front plunger has a bearing immediately after the front one-way seal member when the front plunger is at a predetermined retraction limit. 1 A front relief port is provided to communicate between the oil sump and the front hydraulic chamber.
The present invention also relates to an improvement of the tandem type master cylinder in which the rear plunger is provided with a rear relief port that communicates between the second oil reservoir and the rear hydraulic chamber immediately after the rear one-way seal member when the rear plunger is at a predetermined retraction limit.

(2) Prior art This type of master cylinder is, for example,
As disclosed in Japanese Patent No. 16952, this is already known, and in order to fix the sleeve to the cylinder body, a bearing that abuts the rear end of the sleeve is screwed onto the cylinder body.

(3) Problems to be Solved by the Invention In the above master cylinder, it is important to ensure the coaxiality of the bearing screwed onto the cylinder body with respect to the sleeve fitted into the cylinder hole of the cylinder body. This is extremely difficult, and when the rear plunger slides between these two areas, there is a risk that the sliding resistance will increase or the sliding surface may become galled.

The present invention has been made in view of the above points, and
It is an object of the present invention to provide the above-mentioned tandem type master cylinder in which the coaxiality of the bearing with respect to the sleeve can be easily ensured, and thereby the rear plunger can always slide smoothly.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a cylinder body with a plurality of inwardly facing holes located at the rear end opening of the cylinder hole and directed radially inward. A cylindrical part rotatably fitted into the cylinder hole and abutting the rear end of the sleeve, and a notch between adjacent inward protrusions on the rear end of the cylindrical part are provided. It is composed of a plurality of outward protrusions that pass through and engage with the front surfaces of the plurality of inward protrusions by rotation of the cylindrical part, and intervenes between adjacent outward protrusions in at least one notch part. It is characterized by being equipped with a stop member.

(2) Effect When the cylindrical portion of the bearing is fitted into the cylinder hole as described above, coaxiality of the bearing with respect to the sleeve can be easily ensured in terms of processing accuracy.

In addition, the bearing can be easily attached to and removed from the cylinder body through extremely simple operations such as insertion and removal of the bearing in the cylinder hole, rotation, and attachment and detachment of the stop member, which improves the maintainability of the master cylinder. can.

(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 , 9 ₂ to the cylinder hole 10 of the cylinder body 1
will be communicated with. The cylinder hole 10 includes a first hole 10a with a closed front end, a second hole 10b having a larger diameter than the first hole 10a and continuous to the rear end, and the second hole 10a.
It consists of a third hole 10c which has a larger diameter than b and is continuous to the rear end and has an open rear end. The large-diameter front part a of the front bulkhead collar 12 ₁ is fitted into the second hole 10 b, and the rear surface of the flange c between the large-diameter front part a and the small-diameter rear b of this collar 12 ₁ is fitted into the third hole 10 c. The mounted sleeve 13 abuts, and the small diameter rear portion b is fitted into the front end of the sleeve 13. The large-diameter front part a of the rear bulkhead collar 12 ₂ is fitted into the rear end of the sleeve 13, and a third hole 10c is arranged in 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 12 ₂ . The provided bearing 14 is brought into contact with the bearing 14, and 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 peripheral 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 .

Front bulkhead collar 12 ₁ and sleeve 13 Front and rear bulkhead collar 12 ₂ and sleeve 13
A pair of front and rear plungers 16 ₁ and 16 ₂ are fitted to the rear portion so as to be slidable in the front and rear direction, and a front hydraulic chamber 17 ₁ is defined between the front plunger 16 ₁ and the front end wall of the first hole 10a. Also, both plungers 16 ₁ , 1
A rear hydraulic chamber 17 ₂ is defined between 6 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 6, 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 the hole 3
1 ₂ accommodates a rear return spring 30 ₂ that urges the plunger 16 ₂ in the backward direction. 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, 3, and 6, a plurality of notches n are formed at equal intervals on the circumference in the flange portion c of the rear partition wall collar ₁₂₂ . Also, the large diameter front part a
A plurality of radial grooves 34 ₂ are formed on the front surface of the radial grooves 34 ₂ so as to cut into each notch n.
It communicates with the rear annular oil chamber ₁₁₂ via. The rear one-way seal member 35 ₂ , which only allows the flow of hydraulic oil from these radial grooves 34 ₂ to the long axial groove 23 ₂ of the sleeve 13, has its lip brought into close contact with the outer circumferential surface of the rear plunger 16 ₂ so that the sleeve 13 It is attached to the rear end of the

Also, at the rear end of the sleeve 13 is a retainer 36 ₂ that holds the front end of the rear one-way seal member 35 _{2 .}
and an annular spacer 37 ₂ interposed between the rear one-way seal member 35 ₂ and the rear bulkhead collar 12 ₂ .

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 16 is located in the recess 15 of the bearing 14.
Seal member 39 ₂ that brings the lip into close contact with the outer peripheral surface of 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 fact that its rear end abuts against the flange portion 33 a of the spring holding 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 lip closely connected to the outer circumferential surface of the front plunger 16 ₁ , and is connected to the second hole. 10b.

The second hole 10b also includes a retainer 36 ₁ that holds the front end of the front one-way seal member 35 ₁ and an annular spacer 37 1 interposed between the seal member 35 ₁ and the front partition collar 12 _{1 .} Or installed.

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.

Further, a sealing member 39 ₁ is attached to the front end of the sleeve 13 to bring the lip into close contact with the outer peripheral 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 and 3, 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
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 rotation of the bearing 14 is prevented by a stop spring 48 as a stop member, and the stop spring 48 includes a U-shaped portion 49 that urges opposing pieces 49a and 49b in a direction to separate them from each other, and each opposing piece 49.
facing pieces 49a,
Engagement piece 50 bent at an acute angle to the outside of 49b
It consists of a 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 both engaging pieces 4
The tips of 9a and 49b engage with the opposing surfaces of adjacent outward protrusions 43 and the front surfaces of adjacent inward protrusions 41, respectively. Due to this engagement, the notch 46
The stop spring 48 is prevented from falling off, and the bearing 14 is prevented 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 , 1
It is output from 8 ₂ and can operate two hydraulic brake systems at the same time to brake the car.

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 lips of the corresponding one-way seal members 35 ₁ , 35 ₂ will bend toward the hydraulic chambers 17 ₁ , 17 ₂ due to the pressure difference between the front and rear, so that 1 oil reservoir 8 ₁ is supplied to the front hydraulic chamber 17 1 through the through hole 9 ₁ , the front annular oil chamber 11 ₁ , the radial groove 34 ₁ and the inside of the lip of the front one-way seal member _{35 1 .} , and the hydraulic oil in the second oil reservoir ₈₂ is
Through hole 9 ₂ , rear annular oil chamber 11 ₂ , radial groove 34 ₂ ,
The rear hydraulic chamber 17 ₂ is supplied through the inner side of the lip of the rear one-way seal member 35 ₂ and through the long axial groove 23 ₂ .

At this time, if excess hydraulic oil is supplied to each hydraulic chamber 17 ₁ , 17 ₂ , the excess amount will be absorbed by each relief port 38 ₁ , 38 ₂ when each plunger 16 ₁ , 16 ₂ returns to the retraction limit. The oil is discharged from the oil sump 8 ₁ and 8 ₂ side.

By the way, 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 are pressed against the front and rear partition collars 12 ₁ and 12 ₂ via the spacers 37 ₁ and 37 ₂ . However, as described above, the inner end d of each radial groove 34 ₁ , 34 ₂ is connected to each spacer 37 ₁ , 34 2 .
Since it is located radially outward from the inner peripheral edge e of 37 ₂ , the front and rear one-way seal members 35 ₁ , 3
The rear inner peripheral edge of the front and rear plungers _{16 1} does not dig into the radial grooves 34 _{1 and} 34 ₂ , thereby improving the durability of the front and rear one-way seal members 35 ₁ and 35 ₂ . , 16 ₂ can be advanced and retreated smoothly.

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, the coaxiality of the bearing with respect to the sleeve can be easily ensured, and the rear plunger can always slide smoothly. Furthermore, the bearing can be easily attached and detached from the master cylinder body, thereby improving the maintainability of the master cylinder.

[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-
Line sectional view, Figure 4 is line sectional view of Figure 1- Line sectional view, Figure 5
The figure is a sectional view taken along the line of FIG. 4, and FIG. 6 is an exploded perspective view of the main parts. M...tandem type master cylinder, 1... cylinder body, 8 ₁ , 8 ₂ ... first and second oil sump, 10...
... Cylinder hole, 13 ... Sleeve, 14 ... Bearing, 16 ₁ , 16 ₂ ... Front, rear plunger, 17
₁ , 17 ₂ ... Front, rear hydraulic chamber, 30 ₁ , 30 ₂ ...
Front and rear return springs, 35 ₁ , 35 ₂ ... front and rear one-way seal members, 38 ₁ , 38 ₂ ... front and rear relief ports, 41 ... inward projection, 42 ... cylindrical part, 43 ... ...Outward projection, 46...Notch, 4
8...Stop spring as a stop member.

Claims (1)

[Claims] 1 A cylinder body provided with first and second oil reservoirs, a sleeve fitted into a cylinder hole of this cylinder body, and a front end wall of the cylinder hole which is slidably fitted into this sleeve. a front plunger defining a front hydraulic chamber; a rear plunger slidably fitted within a sleeve to define a rear hydraulic chamber between the front plunger; and a rear plunger that moves the front plunger in a backward direction. a front return spring that biases the rear plunger; a rear return spring that biases the rear plunger in the backward direction; a front one-way seal member that is attached to the cylinder hole and brings the lip into close contact with the outer peripheral surface of the front plunger; a rear one-way seal member that is attached to bring the lip into close contact with the outer circumferential surface of the rear plunger; a bearing that is attached to the cylinder body to slidably support the outer circumferential surface of the rear plunger behind the rear one-way seal member; The front plunger is provided with a front relief port that communicates between the first oil reservoir and the front hydraulic chamber immediately after the front one-way seal member when the front plunger is at a predetermined retraction limit, and the rear plunger is provided with a front relief port that communicates between the first oil sump and the front hydraulic chamber immediately after the front one-way seal member. In the tandem type master cylinder, which is provided with a rear relief port that communicates between the second oil sump and the rear hydraulic chamber immediately after the rear one-way seal member when the cylinder is at a predetermined retraction limit, there is a cylinder hole in the cylinder body. A plurality of inward protrusions are provided at the rear end opening and extend radially inward, and the bearing is connected to a cylindrical portion rotatably fitted into the cylinder hole and abutting the rear end of the sleeve, and the cylindrical portion. a plurality of outward protrusions that are located at the rear end of the part, pass through a notch between adjacent inward protrusions, and engage with the front surfaces of the plurality of inward protrusions, respectively, by rotation of the cylindrical part; A tandem-type master cylinder, characterized in that a stop member that intervenes between adjacent outward protrusions is attached to at least one notch.