JP2516773B2 - Tandem master cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a cylinder body having first and second oil reservoirs, and a sleeve fitted in a cylinder hole of the cylinder body. And a front plunger that is slidably fitted in the sleeve to define a front hydraulic chamber between the front end wall of the cylinder hole and a front hydraulic chamber between the front plunger and the front plunger. A rear plunger that is slidably fitted in the sleeve, a front return spring that is compressed in the front hydraulic chamber to bias the front plunger in the backward direction, and a rear plunger in the backward direction. A rear return spring that is compressed in the rear hydraulic chamber,
It consists of a front one-way seal member that is attached to the cylinder hole to bring the lip into close contact with the outer peripheral surface of the front plunger, and a rear one-way seal member that is attached to the sleeve to bring the lip into close contact with the outer peripheral surface of the rear plunger. The front plunger is provided with a front relief port which communicates between the first oil reservoir and the front hydraulic chamber immediately after the front one-way seal member when it is at a predetermined retract limit, and the rear plunger is The present invention relates to an improvement of a tandem type master cylinder 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 is in a predetermined retreat limit.

(2) Prior Art This type of master cylinder is known as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-16952, and in this known art, at the time of assembly, a sleeve is provided in a cylinder hole of the cylinder body. A front return spring, a front plunger, a rear return spring, and a rear plunger are sequentially inserted, and finally a cover is attached to the rear end of the cylinder body to prevent the rear plunger from coming off.

(3) Problems to be Solved by the Invention In the tandem type master cylinder as described above, the retreat limit defining means for the front plunger is not provided between the plunger and the sleeve, and the rear end of the front plunger is not provided. Since the rear return spring holding cylinder and the rear plunger are in contact with each other so as to be separable from each other, the sleeve is separated from the cylinder body, and the front and rear plungers are set in place in the sleeve. It is not possible to make a small assembly as a whole, so when assembling the master cylinder, insert the sleeve, front return spring, front plunger, rear return spring, rear plunger, etc. individually into the cylinder hole of the cylinder body one after another. Finally, since a cover must be attached to the rear end of the cylinder body to prevent the rear plunger from coming off, assembly work efficiency is poor overall. In addition, there is a problem in that when the master cylinder is fully assembled, it is necessary to specially extend a stopper for preventing the rear plunger from slipping out at the rear end of the cylinder body, which increases the overall length of the cylinder body. .

The present invention has been proposed in view of the above, and an object thereof is to provide a tandem master cylinder that can solve all the above problems of the conventional one.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a front plunger with a protrusion protruding from the outer peripheral surface thereof, and the protrusion is provided from the front side of the sleeve. A sleeve is provided with an axial guide groove that slidably engages and a stopper wall that receives the protruding piece and defines the retreat limit of the front plunger, and has an enlarged head on one of the front and rear plungers. Has a guide shaft projecting toward the other side, and a holding cylinder that can slide on the guide shaft and that abuts the enlarged head of the holding cylinder that defines the backward limit of the rear plunger.
A subassembly of the sleeve and the front and rear plungers is formed by locking the other of the rear plungers in the axial direction so as not to be able to move relative to each other, and when the subassembly is inserted into the cylinder bore from its rear side, the sleeve from the cylinder bore is inserted. A feature of the present invention is that a retainer member for preventing disengagement is attached to the cylinder body.

(2) Operation During mass-production assembly of the master cylinder, the protrusion of the front plunger and the stopper wall of the sleeve are engaged with each other, and the guide shaft fixed to one plunger and the other plunger are immovably fixed in the axial direction. Based on the contact with the stopped holding cylinder, a small assembly in which the front and rear plungers are collectively placed in a fixed position in the sleeve can be preassembled on a line different from the completed assembly line. In the completed assembly line, it is only necessary to insert the above-mentioned subassembly into the cylinder hole of the cylinder body and mount the pressing member on the cylinder body, that is, to perform the above-mentioned subassembly and the whole assembly separately and efficiently. it can.

Further, when the master cylinder is completely assembled, the rearward limit of the rear plunger can be defined by utilizing the engagement between the front plunger projection and the stopper wall of the sleeve.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, in FIG. 1 and FIG. 4, M is a tandem type master cylinder for a two-system hydraulic brake of an automobile, the cylinder body 1 of which is located 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 sump cylinder 3 is integrally provided on the upper side of the cylinder body 1, and a main oil sump cylinder 4 is connected thereto. The main oil sump 4 has a cap 5 at the upper end, and a known oil level sensor 6 supported by the cap 5 is provided inside.

The inside of the auxiliary oil sump cylinder 3 is divided into the first and second oil sumps by the partition wall 7.
8 _1, 8 ₂ is partitioned into these oil reservoir 8 _1, 8 ₂ is supplemented with hydraulic fluid from the main oil reservoir tube 4, respectively.

The first and second oil reservoirs 8 ₁ and 8 ₂ are front and rear through holes 9 ₁ and 9 _{2 respectively.}
Through the cylinder hole 10 of the cylinder body 1.
The cylinder hole 10 includes a first hole 10a whose front end is closed, and the first hole 10a.
a second hole 10b having a diameter larger than a and continuing to the rear end, and this second hole 10b
The third hole 10c has a diameter larger than that of the hole 10b and is connected to the rear end of the hole 10b, and the rear end is open. The second hole 10b and the third hole 10c.
The partition collar 12 is fitted in the step portion between them, and the sleeve 13 fitted into the rear end of the collar 12 and the bearing 14 fitted into the rear end of the sleeve 13 are fitted into the third hole 10c. An annular cap screw 15 that is mounted and presses the rear surface of the bearing 14 is screwed into the rear opening of the third hole 10c.

The outer peripheral surface of the sleeve 13 defines a front annular oil chamber 11 ₁ connected to the front through hole 9 ₁ and a rear annular oil chamber 11 ₂ connected to the rear through hole 9 ₂ in the third hole 10c.

A pair of front and rear plungers 16 ₁ and 16 ₂ are slidably fitted to the sleeve 13, 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. 16 _1, 16 ₂
A rear hydraulic chamber 17 ₂ is defined therebetween. These hydraulic chambers 17 ₁ , 17 ₂
Are communicated with the two brake hydraulic circuits of the two systems 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 extends rearward of the cylinder body 1 through a bearing 14, further enters into the booster shell 2, the output of the vacuum booster B is articulated hole 45 bottomed opening at its rear end The rod 19 is inserted.

The booster shell 2 through which this rear plunger 16 ₂ penetrates
For a negative pressure from the hole 20 of the inside of to prevent leakage, the seal member 21 to close the lip on the outer peripheral surface of the rear plunger 16 ₂ is held between the cylinder body 1 and the booster shell 2.

In order to connect the rear hydraulic chamber 17 ₂ and the rear output port 18 ₂ to each other, the sleeve 13 has three axial grooves 23 running on the inner peripheral surface from the front end to the rear end and an annular groove 25 running on the outer peripheral surface. , And a lateral hole 24 that communicates between each axial groove 23 and the annular groove 25.

The front end surface of the rear plunger 16 _2, the spring holding hole ₃₁₂ with a bottom for receiving the rear return spring 30 ₂ urges the plunger 16 ₂ in the backward direction is provided. Also front plunger 16 ₁
To the rear end, the guide shaft 32 protruding to a predetermined length axis direction toward the rear plunger 16 ₂ is screwed across the seat plate 46, it is enormous head 32a is formed at the front end. This guide shaft 32
A hat-shaped holding cylinder 33 is slidably fitted in the
The top wall of the holding cylinder 33 comes into contact with the enlarged head 32a so as not to be pulled out from the guide shaft 32. Rear return spring 30 ₂ a outward flange 33a formed at the rear end of the holding cylinder 33 between the seat plate 46 is mounted under compression.

The seat plate 46 is provided with three projecting pieces 46a that project radially from the peripheral surface of the front plunger 16 _1.
Three axial guide grooves 28 with which 6a slidably engages are formed in the inner peripheral wall of the sleeve 13 alternately with the axial grooves 23 on the circumference. These guide grooves 28 start from the front end of the sleeve 13 and end in the middle thereof, the end of which is closed by a stopper wall 29 integral with the sleeve 13.

As clearly shown in FIG. 3, the guide groove 28 has a protrusion 46a.
In order to allow the oil in the guide groove 28 to flow in front of and behind the protruding piece 33a along with the forward and backward sliding of the protruding piece 33a, a cross-sectional shape sufficiently larger than that of the protruding piece 46a is given, and the axial groove 23 has the protruding piece 46a. In order to prevent an erroneous assembly in which the protrusions 46a are inserted, the protrusion 46a is provided with a cross-sectional shape that cannot be inserted.

As clearly shown in FIG. ₂ , the spring hole 31 ₁ of the rear plunger 16 ₂ has a large-diameter hole 31a which opens at the rear end face of the plunger 16 ₂ and is larger than a locking ring 48 described later, and a taper to the large-diameter hole 31a. A small diameter hole 31c that is connected to the rear return spring 30 _{2 and} has a diameter slightly larger than that of the rear return spring 30 _2.
An annular locking groove 47 adjacent to the bottom surface is formed on the peripheral surface of the small diameter hole 31c. Meanwhile, the rear return spring 30
_A locking ring 48 is formed at the rear end of _{2 so that} the end thereof can be expanded and elastically engaged with the locking groove 48. Further, the outward flange 33a of the holding cylinder 33 is formed to have a diameter slightly smaller than that of the small diameter hole 31c so as to contact the bottom surface thereof.

Then, the rear return spring 30 ₂ is attached to the spring hole 31 ₂ from the side of the locking ring 48.
, The locking ring 48 passes through the large diameter hole 31a, is then reduced in diameter by the tapered portion 31b and is guided to the small diameter hole 31c, and
When it reaches 47, it expands in diameter due to its own elasticity and engages with the locking groove 47. At this time, the retaining ring 48 cooperates with the bottom surface of the small diameter hole 31c to clamp the outward flange 33a of the holding cylinder 33. Holding cylinder 33 is in this manner locked in relatively immovable engagement with the plunger axis direction through the rear return retaining ring 48 of the spring 30 ₂ to the locking groove 47 of the rear plunger 16 _2.

Incidentally, projecting a guide shaft 32 in the rear plunger 16 _2, the holding cylinder 3
The 3 may be locked to the front plunger 16 ₁ so as to be relatively immovable in the axial direction thereof.

Referring again to FIGS. 1 and 4, a plurality of radial grooves 34 ₂ are provided at the front end of the bearing 14, and a plurality of axial grooves communicating between the radial grooves 34 ₂ and the rear annular oil chamber 11 ₂ are provided. 40 is provided on the outer peripheral surface of the sleeve 13. Rear direction seal member 35 ₂ is mounted on the sleeve 13 the rear end by close contact with the outer peripheral surface of the lip rear plunger 16 ₂ to permit the flow of oil from the radial grooves 34 ₂ to the sleeve 13 axial groove 23 To be done.

Further, at the rear end of the sleeve 13, a rear one-way seal member 35
A retainer 36 ₂ for holding the _second front end portion, and the spacer 37 ₂ is inserted between the rear direction seal member 35 ₂ and the bearing 14 is mounted.

The rear plunger 16 _2, when it is in the retracted limit,
Rear relief port 38 ₂ communicating between radial grooves 34 ₂ and the spring hole 31 ₂ immediately after the rear one-way sealing member 35 ₂ is bored.

The sealing member 3 is in an annular groove 41 formed on the inner peripheral surface of the bearing 14 to close the lip on the outer peripheral surface of the rear plunger 16 ₂
9 ₂ is installed.

On the other hand, the front end of the front plunger 16 ₁ extends through the partition wall collar 12 to the first hole 10a, and its front end face is
Front return spring 3 which biases the front plunger 16 ₁ in the backward direction
0 ₁ spring hole 31 ₁ bottomed for receiving is provided.

The partition wall collar 12 is provided with a radial groove 34 ₁ continuous with the front annular oil chamber 11 ₁ , and from this groove 34 ₁ to the front hydraulic chamber 17 ₁
Front one-way seal member that allows only oil flow to 35 ₁
However, the lip is attached to the second hole 10b with the outer surface of the front plunger 16 ₁ being in close contact.

The second hole 10b, also, the retainer 36 ₁ for holding a front end portion of the front one-way sealing member 35 _1, spacer 37 ₁ is inserted between the seal member 35 ₁ and the partition wall collar 12 is attached.

The front plunger 16 ₁ has a
Radial grooves 34 ₁ and the front relief port 38 ₁ for communicating between the spring hole 31 ₁ is drilled.

Also in the annular recess 42 formed in the front end portion of the sleeve 13, the seal member 39 ₁ to close the lip on the outer circumferential surface of the front plunger 16 ₁ it is mounted.

 Next, the operation of this embodiment will be described.

Now, when the negative pressure booster B is operated to move the output rod 19 forward, both plungers 16 ₁ and 16 ₂ are pushed by the negative pressure booster B to move forward while compressing the corresponding return springs 30 ₁ and 30 ₂ . When the relief port 38 ₁ of the front plunger 16 ₁ is moved to the front of the front one-way sealing member 35 _1, hydraulic pressure is generated in the front hydraulic chamber 17 ₁ in response to the advancing force of the front plunger 16 _1, also the relief port 38 ₂ of the rear plunger 16 ₂ moves forward of the rear one-way sealing member 35 _2, hydraulic pressure is generated in the rear pressure chamber 17 ₂ in response to the advancing force of the rear plunger 16 _2.

In this way, the hydraulic pressure generated in the front and rear hydraulic chambers 17 ₁ and 17 ₂ is output from the corresponding output ports 18 ₁ and 18 _2, and the hydraulic brakes of the two systems can be simultaneously actuated to brake the vehicle.

When the negative pressure booster B is returned to the inoperative state in order to release the braking, each plunger 16 ₁ , 16 ₂ causes the corresponding return spring 30 ₁ , 30 ₂
Each of the hydraulic chambers 17 ₁ and 17 ₂ is depressurized by the repulsive force of the one-way seal members 35 ₁ and 35 ₂ due to the pressure difference between the front and back. Since the hydraulic oils 17 ₁ and 17 ₂ are bent toward the hydraulic chambers 17 ₁ and 17 ₂ respectively, the working oil in the _first oil sump 8 ₁ passes through 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. supplemented through the inner _one of the lip to the front hydraulic chamber 17 _1, and the second oil reservoir ₈₂ of hydraulic fluid, through holes 9 _2, rear annular oil chamber 11 _2, Jikukatamizo 40, radial grooves 34 _2, The oil is supplied to the rear hydraulic chamber 17 ₂ through the inside of the lip of the rear one-way seal member 35 ₂ and the axial groove 23.

At this time, an excessive supply of the hydraulic chambers 17 _1, 17 ₂ to the hydraulic oil is performed, the excess, when the plungers 16 _1, 16 ₂ is returned to the retreat limit, the relief ports 38 _1, 38 ₂ Oil sump 8 ₁ ,
8 ₂ Released to the side.

By the way, the projecting piece 46a of the seat plate 46 fixed to the front plunger 16 ₁ is slidably engaged with the guide groove 28 extending in the axial direction of the sleeve 13, so that the seat plate together with the front plunger 16 _{1 is} seated. There is nothing to prevent the 46 from moving back and forth.

Further, when the front and rear plungers 16 ₁ and 16 ₂ are retracted, the projecting piece 46a is first received by the stopper wall 29 at the end of the guide groove 28 to define the retracting limit of the front plunger 16 ₁ ,
Then retreat limit of the rear plunger 16 ₂ is defined by the abutment of the large head 32a and the holding cylinder 33 of the guide shaft 32.

Is hitting the mass assembly of such tandem type master cylinder M, the first of the assembly line, the guide shaft in the rear back seat plate 46 and the holding cylinder 33 to face each other across the spring 30 ₂ 32
The inserted, the guide shaft 32 is screwed to the rear end of the front plunger 16 _1, then the front plunger 16 ₁ into the guide groove 28 of the projecting piece 46a of the seat plate 46 is inserted from the front into the sleeve 13 After engaging, the holding tube 33 and the rear return spring 30 ₂ are attached to the rear plunger 16 ₂
Inserted into the spring hole 31 _2, locking the holding cylinder 33 at the rear plunger 16 ₂ in the manner described above. In this way, the sleeve 13 and the sub-assemblies of the front and rear plungers 16 ₁ and 16 ₂ are assembled.

Next, in the second assembly line, the front part return spring 30 ₁ , the partition wall collar 12, the front and rear one-way seal members 35 ₁ and 35 ₂ and the bearing 14 are attached to the subassembly, and the subassembly is attached to the cylinder. The master cylinder M is completed by fitting it into the cylinder hole 10 of the main body 1 and finally screwing the cap screw 15 onto the cylinder main body 1.

Thus, by performing the small assembly and the completed assembly in parallel, mass productivity can be greatly improved.

Also, in the assembled state, the rear plunger 16 ₂
Since it is connected to the front plunger 16 ₁ through the holding cylinder 33, even if the cap screw 15 is removed for maintenance, the rear plunger 1 is repulsed by the elastic force of the rear return spring 30 _2.
6 ₂ never fly out to the outside, thus can be performed with confidence disengagement of cap screws 15, maintainability is improved.

C. Effects of the Invention As described above, according to the present invention, the front plunger is provided with the projecting piece projecting from the outer peripheral surface thereof, and the projecting piece is slidably engaged from the front side of the sleeve in the axial guide groove. When,
The sleeve is provided with a stopper wall that receives the protrusion and regulates the retracting limit of the front plunger, and a guide shaft with an enlarged head is projected toward one of the front and rear plungers toward the other. A holding cylinder that can slide on the shaft and abuts the enlarged head of the rear plunger to regulate the rearward limit of the rear plunger is fixed to the other of the front and rear plungers so as to be relatively immovable in the axial direction of the sleeve and the front. Since a sub-assembly of the rear plunger is configured and the sub-assembly is inserted into the cylinder hole of the cylinder body from the rear side, a pressing member that prevents the sleeve from coming out of the cylinder hole is attached to the cylinder body. During assembly, the protrusion of the front plunger and the stopper wall of the sleeve are engaged with each other, and the guide shaft fixed to one plunger and the other plunger are locked so that they cannot move axially relative to each other. Based on the contact with the holding cylinder, the small assembly with the front and rear plungers put together in a fixed position in the sleeve is placed in advance in a small assembly line separate from the master cylinder completed assembly line with high accuracy, efficiency and concentration. In a completed assembly line, such a small assembly is simply inserted into the cylinder hole of the cylinder body and the pressing member is attached to the cylinder body. Therefore, the mass production and assembly of the master cylinder is excellent as a whole, and it can greatly contribute to the improvement of the efficiency of the assembly work.

Further, since the rear limit of the rear plunger can be regulated by the engagement between the front plunger protrusion and the stopper wall of the sleeve when the master cylinder is completely assembled, a dedicated rear limit regulating means for the rear plunger is provided on the rear side of the cylinder body. It is not necessary to specifically extend the end portion, which can contribute to the simplification of the structure, and can shorten the axial direction of the cylinder body.

Further, a stopper wall, which is a common backward limit defining means for the front and rear plungers, is provided on the sleeve inserted into the cylinder body. There is no need to provide specially, the seal structure is simplified and the possibility of oil leakage is reduced, and there is no possibility that the retreat limit defining means will be separated from the cylinder body.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a vertical sectional side view of a tandem type master cylinder, FIG. 2 is an enlarged view of an essential part of FIG. 1, and FIG. 3 is III- of FIG. III sectional view, 4th
The figure is an exploded perspective view of the main part of FIG. M: Tandem type master cylinder 1 ... Cylinder body, 8 ₁ , 8 ₂ ... 1st, 2nd oil reservoir, 10 ...
Cylinder hole, 13 …… Sleeve, 15 …… Pressing screw, 16 ₁ , 16
₂ …… Front and rear plungers, 17 ₁ , 17 ₂ …… Front and rear hydraulic chambers, 18 ₁ , 18 ₂ …… Front and rear output ports, 28 …… Guide groove, 2
9 …… Stopper wall, 30 ₁ , 30 ₂ …… Front and rear return springs, 32…
… Guide shaft, 32a… Enlarged head, 33… Holding cylinder, 33a… Outward flange, 46… Seat plate, 46a… Projection piece, 47… Lock groove, 48… Lock ring

Claims (1)

(57) [Claims] 1. A cylinder body (1) having first and second oil reservoirs (8 ₁ , 8 ₂ ) and a sleeve (13) fitted in a cylinder hole (10) of the cylinder body (1). And a front plunger (16 ₁ ) slidably fitted in the sleeve (13) to define a front hydraulic chamber (17 ₁ ) between the front end wall of the cylinder hole (10), A rear plunger (16 ₂ ) slidably fitted in a sleeve (13) to define a rear hydraulic chamber (17 ₂ ) between the front plunger (16 ₁ ) and the front plunger (16 ₂ ). ₁ ) to urge the rearward hydraulic pressure in the front hydraulic chamber (1
The front return spring (30 ₁ ) compressed to 7 ₁ ) and the rear hydraulic chamber (17 ₂ ) to urge the rear plunger (16 ₂ ) in the backward direction.
Rear return spring (30 ₂ ) compressed to the cylinder hole (1
0) to attach the lip to the outer surface of the front plunger (16 ₁ ) and the front one-way seal member (35 ₁ ) and to the sleeve (13) to attach the outer surface of the rear plunger (16 ₂ ). Rear one-way sealing member (35 ₂ ) that keeps the lip in close contact with
The front plunger (16 ₁ ) includes a _first oil sump (8 ₁ ) and a front hydraulic chamber (17 ₁ ) immediately after the front one-way seal member (35 ₁ ) when it is in the retracted limit. ) Is provided with a front relief port (38 ₁ ) and a rear plunger (1
6 ₂ ) includes a _second oil sump (8 ₂ ) and a rear hydraulic chamber (1 ₂ ) immediately after the rear one-way seal member (35 ₂ ) when it is at the backward limit.
7 ₂ ) In a tandem type master cylinder provided with a rear relief port (38 ₂ ) communicating with each other, the front plunger (16 ₁ ) is provided with a projecting piece (46a) projecting from its outer peripheral surface, and this projecting piece is also provided. The axial guide groove (2) in which (46a) slidably engages from the front of the sleeve (13).
8) and the protrusion (46a) to receive the front plunger (1
A stopper wall (29) that defines the retreat limit of 6 ₁ ) is provided on the sleeve (13), and a guide shaft (32a) with an enlarged head (32a) is provided on one of the front and rear plungers (16 ₁ , 16 ₂ ). ) Projecting toward the other side and slidable on the guide shaft (32) and contacting the enlarged head (32a) of the holding shaft (33) for defining the backward limit of the rear plunger (16 ₂ ). ) Front and rear plunger (16
_1, 16 ₂₎ other on and sealed relatively immovable engaged in the axial direction of the sleeve (13) and front and rear plunger (16 _1, 1
6 ₂ ) A subassembly for holding the sleeve (13) from the cylinder hole (10) when the subassembly is inserted into the cylinder hole (10) of the cylinder body (1) from the rear of the subassembly. A tandem master cylinder characterized in that (15) is attached to the cylinder body (1).