JPH0144383Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention uses a double master cylinder to
A brake hydraulic pressure control device for a vehicle braking system, which has a brake hydraulic circuit configured into two independent systems, in particular a brake hydraulic pressure system that supplies hydraulic pressure lower than the front wheel brake hydraulic pressure as the rear wheel brake hydraulic pressure. This relates to a control device.

Conventionally, as shown in FIG.
The rear wheel brakes B, Br' and B', Br have independent first and second output ports extending from the first and second output ports of the double master cylinder M to the hydraulic operating parts of the rear wheel brakes B, Br' and B', Br.
There is a type in which the flow paths L ₁ and L ₂ are connected separately.
In this type of braking system, during heavy braking, each rear wheel brake hydraulic pressure is automatically reduced at a fixed ratio to the front wheel brake hydraulic pressure of the same system, and the load on the rear wheels is reduced by tilting the vehicle forward. In order to obtain efficient braking even when the
It is known that a common brake hydraulic control device C is provided between L ₁ and L ₂ and the rear wheel brakes Br and Br'.

The present applicant has previously proposed the above-mentioned first device as such a device.
A common housing is interposed in the middle of the second flow path, a pair of left and right pressure receiving pistons are slid into the cylinder holes in the housing, and the pressure receiving pistons are connected to the inner ends of the first and second flow paths. First and second input hydraulic chambers that communicate separately upstream, and first and second input hydraulic chambers that communicate separately downstream of both flow paths on the outer end side.
In addition to forming output hydraulic chambers, the pressure receiving area on each output hydraulic chamber side of each pressure receiving piston is made larger than the receiving pressure area on each input hydraulic chamber side, and the space between each adjacent input and output hydraulic chambers is Communicates through a valve that opens at the limit of outward sliding and closes at inward sliding,
We proposed a common pressure regulating spring compressed between both pressure receiving pistons.

The above-mentioned housing is generally divided into a pair of housing halves in the axial direction to facilitate processing and assembly of the internal mechanism, and these housing halves are connected to each other. They are butted together and connected with multiple bolts. However, with this method of connecting the two housing halves, not only is the assembly complicated and time-consuming, but also the internal adjustment is difficult when the two housing halves are rotated relative to each other in order to align the bolt holes in the housing halves. Twisting a pressure spring or the like may change its spring characteristics.

An object of the present invention is to provide the above-mentioned device, which has a simple structure and does not have the above-mentioned drawbacks, by making it possible to reliably connect both housing halves with one connecting tube.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, the dual master cylinder M is configured in a tandem type. ₁ and ₂ are the first and second output ports, respectively.
Pressure oil is supplied from P ₁ and P ₂ to the first and second flow paths L ₁ and L ₂ , and this pressure oil is guided to the front wheel brakes B and B' and the brake hydraulic control device C. There is.

The brake hydraulic control device C is configured symmetrically. The housing 3 consists of a pair of left and right housing halves 3 _{1 and 3 2} that are divided in the axial direction. An open positioning recess 3b is formed. Both housing halves 3 ₁ ,
3 ₂ is with those divided planes butted against each other,
The housing halves 3 1 and 3 2 are connected by a connecting cylinder 4 that is fitted inside them, thereby maintaining the coaxial arrangement of both housing halves 3 ₁ and 3 ₂ . On the peripheral wall of the connecting cylinder 4, a second
As shown in Fig. 3, two lines aligned in the generatrix direction are cut and raised outward so that the tip surfaces can face each other.
A set of one-way locking claws 4a are provided at three locations at equal intervals on the circumference. Furthermore, a positioning protrusion 4b extending in the generatrix direction is provided on the outer peripheral surface of the connecting cylinder 4 in a protruding manner. These one-way locking pawls 4a and positioning protrusions 4b are formed by press molding on a steel plate, which is the material of the connecting tube 4, and then the connecting tube 4 is obtained by bending the steel plate into a cylindrical shape. 4c is a seam.

When connecting the two housing halves 3 ₁ and 3 ₂ , they are fitted into the connecting tube 4 from both ends, their divided surfaces abutted against each other, and the positioning protrusions 4b are engaged with the positioning recesses 3b that communicate with each other, Further, each one-way locking pawl 4a is locked in each locking recess 3a. During this connection, each one-way locking pawl 4a connects the housing half 3 ₁ ,
3 It is pressed by the inner peripheral surface of ₂ and bends inward, so
Both housing halves 3 ₁ , 3 ₂ and the connecting cylinder 4 are allowed to fit together, while each one-way locking pawl 4a is inserted into each locking recess 3
When it is locked in a, the connecting cylinder 4 and both housing halves 3 ₁ ,
3 Secession with ₂ is prevented. Furthermore, the coupling cylinder 4 is prevented from rotating by the engagement between the positioning recess 3b and the positioning protrusion 4b.

The housing 3 has cylinder holes 7 ₁ and 7 ₂ and a large diameter hole 8 having a larger diameter than the cylinder holes 7 1 and 7 2 and into which the connecting cylinder 4 is fitted.
₁ , 8 ₂ are formed, and each cylinder hole 7 ₁ ,
Pressure receiving pistons 9 ₁ and 9 ₂ having the same diameter are slidably connected to each other on 7 ₂ . Small cylinder holes 10 ₁ , 10 ₂ having the same diameter are formed in each pressure receiving piston 9 ₁ , 9 ₂ , and these small cylinder holes 10 ₁ , 10 ₂ have
Valve moving pistons 11 whose backs abut each other
₁ and 11 ₂ are sliding together.

In the large diameter holes 8 ₁ , 8 ₂ , both pressure receiving pistons 9 ₁ ,
9. On the outer periphery of the axially intermediate portion of ₂ , there is a shoulder portion 3 facing oppositely.
1 ₁ , 31 ₂ are formed, and these shoulder parts 31 ₁ , 31 ₂
A common relatively strong coiled pressure regulating spring 12 is compressed between them via washers 32 ₁ and 32 ₂ that abut against them. Therefore, the pressure regulating spring 12 surrounds the opposing inner ends of the pressure receiving pistons 9 ₁ and 9 ₂ .

Further, between the two valve moving pistons 11 ₁ and 11 ₂ , shoulder portions 13 ₁ and 13 ₂ of each piston 11 ₁ and 11 ₂ are provided.
and the inner and outer shoulder portions 1 of the small cylinder holes 10 ₁ and 10 ₂
A relatively weak coil-shaped positioning spring 17 is compressed through washers 16 ₁ and 16 ₂ that can abut on _{4 1} and 14 ₂ and 15 1 and 15 ₂ , respectively.

First and second input hydraulic chambers 18 ₁ , 18 ₂ are connected to the outer ends of the valve moving pistons 11 ₁ , 11 ₂ in both small cylinder holes 10 ₁ , 10 ₂ , and both cylinder holes 7 ₁ , 7 ₂ includes pressure receiving pistons 9 ₁ , 9 ₂
The first and second output hydraulic chambers 19 ₁ ,
19 ₂ are respectively defined, and these first and second input hydraulic chambers 18 ₁ , 18 ₂ have inflow ports 20 ₁ ,
Upstream of the first and second flow paths L ₁ , L ₂ via 20 ₂ are also connected to the first and second output hydraulic chambers 19 ₁ , 1
9 ₂ has both passages through outflow ports 21 ₁ and 21 ₂
The downstream sides of L ₁ and L ₂ are connected so that they are always in communication with each other.

The end walls of the small cylinder holes 10 ₁ and 10 ₂ are provided between adjacent input and output hydraulic chambers 18 ₁ and 19 ₁ and between the adjacent input and output hydraulic chambers 18 1 and 18 ₂ , 1
Communication holes 22 ₁ , 22 ₂ are provided to communicate between the valve opening rods _{24 1} , ₂₄ , which project from the outer ends of the valves _{23 1 ,} 23 ₂ , respectively. ₂ can penetrate. Each valve 23 ₁ , 23 ₂ and valve moving piston 11 ₁ ,
Closing springs _{25 1 and} 25 ₂ are respectively compressed between the valves 11 and 11 2 , and normally the opening rods 24 ₁ and 24 ₂ of the valves 23 ₁ and 23 ₂ are connected to the end walls of the cylinder holes 7 ₁ and 7 ₂ . The valves 23 ₁ and 23 ₂ are held in the open position at the outward sliding limit of each pressure receiving piston 9 ₁ and 9 ₂ . When the pressure receiving pistons 9 ₁ , 9 ₂ move inward and the end walls of the small cylinder holes 10 ₁ , 10 ₂ come into contact with the valves 23 ₁ , 23 ₂ , the communication holes 22 1 , 23 ₂ come into contact with each other.
22 ₂ is occluded.

Connectors 26 ₁ and 26 ₂ are attached to the inner ends of each valve 23 ₁ and 23 ₂ , respectively. The inner ends of these connectors 26 ₁ , 26 ₂ are connected to stoppers provided at the outer ends of the valve moving pistons 11 ₁ , 11 ₂ when the pistons 11 ₁ , 11 ₂ move inward by a predetermined distance ι ₂ . 27 ₁ and 27 ₂ . This distance ι ₂ is equal to the distance between the valves 23 ₁ ,
The distance ι 1 that the pressure receiving pistons 9 ₁ , 9 ₂ move from the valve opening position to the valve closing position of 23 ₂ is greater than the distance ι ₁ and the washer 16 ₁ , 16 with respect to this distance ι ₁ and the small cylinder holes 10 ₁ , 10 ₂ . ₂ is smaller than the sum of the possible distance ι ₃ .

ι ₂ >ι ₁ …(1) ι ₂ <ι ₁ +ι ₃ …(2) Moreover, the distance between the pressure receiving pistons 9 ₁ and 9 ₂ is such that each pressure receiving piston is not interfered with by the other pressure receiving piston. A necessary minimum interval ι ₄ is provided so that ι ₁ can be moved. Therefore, the interval ι ₄ is set equal to twice the distance ι ₁ or slightly larger than that.

ι ₄ ≧ 2 × ι ₁ ...(3) The connecting cylinder 4 connects each washer 32 ₁ , 3 when each pressure receiving piston 9 ₁ , 9 ₂ moves inward by a certain distance ι ₅
2 ₂ to stop its movement, and the distance ι ₅ is set to half the distance ι ₄ .

ι ₅ =ι ₄ /2 (4) Note that the distance ι ₆ that each of the valve moving pistons 11 ₁ , 11 ₂ can move outward away from each washer 16 ₁ , 16 ₂ is the distance ι ₃ and ι Set equal to or greater than the sum of ₅ .

ι ₆ ≧ι ₅ +ι ₃ ...(5) An annular groove 28 is defined on the outer circumferential surface of the divided portion of both housing halves 3 ₁ and 3 ₂ by abutting them, and an annular groove 28 is formed in the annular groove 28 from outside. A seal ring 29 is attached to prevent dust from entering.
This seal ring 29 allows hydraulic oil etc. to flow from the inside to the outside, and seal members 30 ₁ , 30 ₂ between the pressure receiving pistons 9 ₁ , 9 ₂ and the cylinder holes ₇ 1 , 7 _{2 .} If the hydraulic oil leaks into the large diameter holes 8 ₁ , 8 ₂ due to wear and tear on the connecting cylinder 4
It flows out between the outer circumferential surface and the inner circumferential surface of the large-diameter holes 8 ₁ and 8 ₂ , between the dividing surfaces of both housing halves 3 ₁ and 3 ₂ , and between the annular groove 28 and the seal ring 29 to prevent the failure from occurring in the master cylinder M. It is possible to detect this as an abnormal drop in the oil level in the reservoir.

Next, the operation of this embodiment will be explained.
When the master cylinder M is not in operation, both the left and right pressure receiving pistons 9 ₁ and 9 ₂ are pressed to the outward sliding limit shown in the figure by the spring force of the pressure regulating spring 12 and the positioning spring 17, and the valves 23 ₁ and 23 ₂ are The valves are open, and the first and second input and output hydraulic chambers 18 ₁ , 1
9 ₁ and 18 ₂ and 19 ₂ are in communication. Therefore, when the brake pedal 1 is operated here, the output hydraulic pressure of the master cylinder M is transmitted to each downstream of the first and second flow paths L ₁ and L ₂ , and
Rear wheel brakes B, B' and Br, Br' operate simultaneously.

Then, as the output oil pressure of the master cylinder M increases, the first and second input and output oil pressure chambers 18 ₁ , 19 ₁
The pressure inside the pressure receiving pistons 9 ₁ , 19 ₂ also rises, but when the pressure reaches a certain value, the difference in the pressure receiving areas between the inner and outer ends of the pressure receiving pistons 9 ₁ , 9 _{2 increases} .
The differential hydraulic pressure acting on the pressure regulating _{spring 12} and the positioning spring 17 becomes larger than the set load of the pressure regulating spring 12 and the positioning spring 17, and the pressure receiving pistons ₉₁ and ₉₂ slide inward while compressing the pressure regulating spring 12 and the positioning spring 17, respectively. move. On the other hand, even if the valve moving pistons 11 ₁ and 11 ₂ move in either the left or right direction due to the pressure difference between the input hydraulic chambers 18 ₁ and 18 ₂ at this time, the formula (1), that is, ι ₂
> From the relationship ι ₁ , the valve moving piston 11 ₁ , 1
The stoppers 27 ₁ and 27 ₂ of 1 ₂ are still connected to the connector 2.
6 ₁ , 26 ₂ , each valve 23 ₁ , 23 ₂
are pressed outward by the closing springs 25 ₁ , 25 ₂ to maintain the state in which the valve opening rods 24 ₁ , 24 ₂ are in contact with the end walls of the cylinder holes 7 ₁ , 7 ₂ . Therefore, when each pressure receiving piston 9 ₁ , 9 ₂ moves inward by a distance ι ₁ , the valves 23 ₁ , 23 ₂ close the communicating holes 22 ₁ , 22 ₂ . During this period, the braking oil pressure for the rear wheels does not increase.

When the output hydraulic pressure of the master cylinder M further increases, the pressure within the input hydraulic chambers 18 ₁ and 18 ₂ increases, pushing each pressure receiving piston 9 ₁ and 9 ₂ outward.
Therefore, the valves 23 ₁ , 23 ₂ open again, increasing the pressure in the output hydraulic chambers 19 ₁ , 19 ₂ . When this pressure reaches a certain value, the pressure receiving piston 9 ₁ ,
9 ₂ is activated again, the communication holes 22 ₁ and 22 ₂ are closed, and the increase in pressure is stopped. By repeating these actions, the braking oil pressure for each rear wheel gradually increases.

On the other hand, since the output hydraulic pressure of the master cylinder M directly acts on the front wheel brakes B and B', the front wheel braking hydraulic pressure increases rapidly as the output hydraulic pressure of the master cylinder M increases. In this way, when braking is applied strongly, the front wheel brakes B and B' are applied more strongly to the front wheel on the side where the vehicle body leans forward and the downward load increases.
Rear brake for the rear wheel on the side where the load is reduced
Since Br and Br' are operated weakly, efficient braking can be performed without causing skids in each wheel.

Next, one of the systems in the brake hydraulic circuit, for example the second flow path _L2 side, breaks down and the rear wheel brake
Suppose that braking hydraulic pressure is no longer applied to the hydraulic operating part of Br′. At this time, when the brake pedal 1 is operated, the output oil pressure of the master cylinder M is changed to the first flow path _L1.
The first input and output hydraulic pressure chambers 18
₁ , 19 ₁ increases, but the pressure in the second input and output hydraulic chambers 18 ₂ , 19 ₂ does not increase. Therefore, the pressure receiving piston 9 ₁ and the valve moving piston 1
1 ₁ and 11 ₂ both move inward, that is, to the right in the figure, but the amount of movement of the pressure receiving piston 9 ₁ is limited to ι ₅ by the washer 32 ₁ coming into contact with the end surface of the connecting cylinder 4. , On the other hand, the valve moving piston 11 ₁ moves further to the right after the pressure receiving piston 9 ₁ is stopped,
The amount of movement from then is ι ₃ due to the washer 16 ₁ coming into contact with the inner shoulder 14 ₁ of the small cylinder hole 10 ₁ .
regulated by. Therefore, the total stroke of the valve moving piston 11 ₁ is ι ₅ +ι ₃ . At this time, the valve moving piston 11 ₂ is the valve moving piston 11 ₁
Although it is pressed by and moves the same amount, the above equation (5),
That is, from the relationship ι ₆ ≧ι ₅ +ι ₃ , the valve moving piston 1
1. Do not interfere in any way with the above movement of ₁ .

When the valve moving piston 11 ₁ has moved by a predetermined distance ι ₂ or more within the range of the above-mentioned total stroke ι ₃ +ι ₅ , the stopper 27 ₁ at its outer end is engaged with the inner end of the connector 26 ₁ to close the valve 23 ₁ . Since it is moved inward, the valve 23 ₁ is separated from the end wall of the small cylinder hole 10 ₁ and maintained in the open state according to the above equation (2), that is, the relationship ι ₂ <ι ₁ + _ι 3 . As a result, the output hydraulic pressure of the master cylinder M is directly transmitted to the first output hydraulic chamber ₁₉₁ , and the front and rear wheel brakes B' and Br of the first flow path _L1 operate with the same strength. That is, this brake hydraulic control device C is provided with a bypass function.

In addition, in the above embodiment, the valve moving pistons 11 ₁ and 11 ₂ are configured as separate bodies, but
If there is no problem with processing accuracy, these can be integrated.

As described above, according to the present invention, the pressure receiving piston 9
₁ , 9 ₂ , the housing 3 that accommodates the valves 23 ₁ , 23 ₂ and the pressure regulating spring 12 is composed of a pair of left and right housing halves 3 ₁ , 3 ₂ divided in the axial direction, and these housing halves 3 ₁ , A locking recess _3a on the inner circumferential surface of 3 and a positioning recess 3 opening on the dividing surface.
b is provided, and with the divided surfaces of both housing halves 3 ₁ and 3 ₂ abutting each other, the connecting cylinder 4 that is fitted inside them is engaged with the locking recess 3 a and the connecting cylinder 4 is Since the one-way locking pawl 4a that prevents the housing halves 3 ₁ and 3 ₂ from being separated from each other and the positioning protrusion 4b that engages with the positioning recess 3b and prevents the connecting cylinder 4 from rotating, both housing halves can be attached to each other. The bodies 3 ₁ and 3 ₂ can be easily and reliably connected via the connecting cylinder 4, and the connecting cylinder has a small number of parts, making the structure simple. Furthermore, when connecting the housing halves 3 ₁ and 3 ₂ , there is no need to rotate the housing halves 3 ₁ and 3 ₂ relative to each other in order to align the bolt holes of the connecting flanges as in the conventional case. This also contributes to stabilizing performance without causing any twisting.

[Brief explanation of the drawing]

FIG. 1 is a two-system hydraulic circuit diagram of a braking system for an automobile, FIG. 2 is a vertical sectional plan view showing an embodiment of the device of the present invention, and FIG. 3 is a cross-sectional side view of a connecting cylinder. Br, Br′... Rear wheel brake, L ₁ , L ₂ ... 1st,
Second flow path, M...Master cylinder, _P1 , _P2 ...
1st and 2nd output ports, 3...housing, 3 ₁ ,
3 ₂ ... Housing half, 3a ... Locking recess, 3
b...Positioning recess, 4...Connecting cylinder, 4a...One-way locking claw, 4b...Positioning protrusion, 7 ₁ , 7 ₂ ...
... Cylinder hole, 9 ₁ , 9 ₂ ... Pressure receiving piston, 12
... Pressure regulating spring, 18 ₁ , 18 ₂ ... First and second input hydraulic chambers, 19 ₁ , 19 ₂ ... First and second output hydraulic chambers, 23 ₁ , 23 ₂ ... Valves.

Claims (1)

[Scope of utility model registration request] First and second flow paths connecting the first and second output ports P ₁ and P ₂ of the dual master cylinder M and the hydraulic operating parts of the pair of left and right rear wheel brakes Br and Br'.
A common housing 3 is inserted between L ₁ and L ₂ ,
A pair of left and right pressure receiving pistons 9 ₁ , 9 ₂ are slid into the cylinder holes 7 ₁ , 7 ₂ in the housing 3, and the first and second flow paths are formed on the inner end sides of the pressure receiving pistons 9 ₁ , 9 ₂ . The first and _second input hydraulic chambers 18 ₁ and 18 ₂ are connected to the upstream side of L 1 and L ₂ separately, and the outer end side is connected to the downstream side of both flow paths L ₁ and L ₂ respectively. The first and second output hydraulic chambers 19 ₁ , 19 ₂ are formed respectively, and the pressure receiving area of each output hydraulic chamber 19 ₁ , 19 ₂ of each pressure receiving piston 9 ₁ , 9 ₂ is determined by the pressure receiving area of each input hydraulic chamber 18 ₁ , 18 . The pressure receiving area is larger than the pressure receiving area on _{the 2} side, and the adjacent input and output hydraulic chambers 19 ₁ , 19 ₂ are opened at the outward sliding limit of each pressure receiving piston 9 ₁ , 9 ₂ and closed at the inward sliding limit. communicate via the valves 23 ₁ and 23 ₂ ,
In a braking hydraulic control device for a vehicle in which a common pressure regulating spring 2 is compressed between both the pressure receiving pistons 9 ₁ and 9 ₂ , a pair of left and right housing halves 3 ₁ and 3 are obtained by dividing the housing 3 in the axial direction. ₂ , each of the housing halves 3 ₁ and 3 ₂ has a locking recess 3 a on the inner circumferential surface, and a positioning recess 3 b opening on the dividing surface.
The connecting cylinder 4 is fitted into the housing halves 3 ₁ and 3 ₂ with their divided surfaces abutted against each other, and the connecting cylinder 4 is fitted into the connecting cylinder 4 by engaging with the locking recess 3a. a one-way locking pawl 4a for preventing separation from the housing halves 3 ₁ and 3 ₂ ; and the positioning recess 3b.
A braking hydraulic control device for a vehicle, comprising a positioning protrusion 4b that engages with the connecting cylinder 4 to prevent rotation of the connecting cylinder 4.