JPH0611263Y2 - Linkage type hydraulic control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a linkage type hydraulic control valve in which an operation starting point is variable according to a vehicle load.

[Prior Art] Conventionally, as a hydraulic control valve of this type, for example, there is one shown in FIG. That is, the plunger 4 facing the push rod 3 fixed to the link arm 1 with the nut 2 is slidably accommodated in the cylinder hole 6 of the housing 5, and the locking member 7 is provided between the push rod 3 and the plunger 4. Via the proportioning spring 8 via
The return spring 9 is interposed between the housing 5 and the push rod 3, and the relative displacement between the sprung portion and the unsprung portion of the vehicle is converted into a load by a sensor spring (not shown). When the brake fluid pressure input from the input port (not shown) during braking exceeds a predetermined value by pressing the plunger 4 via the, the plunger 3 lifts to open and close the fluid flow passage (not shown). By operating, the brake fluid pressure to the output port (not shown) was controlled.

[Problems to be Solved by the Invention] However, in such a conventional hydraulic control valve, since the push rod 3 directly abuts on the plunger 4 during non-braking, in order to prevent the plunger 4 from being damaged or the like. There is a problem that it is necessary to increase the size of the device, which eventually leads to an increase in the size of the entire device.

Further, by sealing the plunger 4 and the cylinder hole 6 with the cup seal 10 and the backup ring 11, and by locking the backup ring 11 to the snap ring 12 locked at one end of the cylinder hole 6, the backup ring 1
1 has a structure to prevent it from slipping out to the right side of the figure, but if the snap ring 12 falls off under any condition,
The backup ring 11 also falls off from the cylinder hole 6, causing a problem of loss of brake fluid pressure.

[Means for Solving the Problems] The present invention has been made in view of such problems,
It is an object of the present invention to provide a linkage type hydraulic control valve having a structure in which a plunger is miniaturized and a backup ring is completely retained.

To achieve this object, the present invention provides a seat member between the push rod and the plunger for stopping the movement of the push rod toward the plunger side when not braking at a predetermined position by locking with one end of the housing. Set up in.

In addition, a backup ring for retaining the cup seal for sealing between the plunger and the cylinder hole,
A snap ring or the like that is locked to a first ring member such as a snap ring provided at one end of the housing, and is locked and stopped when the seat member facing the plunger moves to a predetermined position on the push rod side. A second ring member at one end of the housing, and
Even if the ring member comes off and the backup ring moves to the seat member side, when the seat member is locked to the second ring member, the backup ring has a sufficient length such that the entire backup ring does not fall out of the cylinder hole. The backup ring length was set.

[Operation] According to the present invention having such a configuration, even if a shock or the like is received during non-braking, the force of the push rod is received by the seat member and is not applied to the plunger. It is not necessary to increase the rigidity to reduce the size of the plunger.

Also, even if the first ring member comes off and the backup ring moves toward the seat member side, the movement of the backup ring is restricted by the second ring member and the entire ring does not fall out of the cylinder hole, so brake fluid leakage is prevented. Can be reliably performed.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 showing the structure of this embodiment, 13 is a housing of a hydraulic pressure control valve 14, and an input port 15 into which hydraulic pressure from a master cylinder is input to the housing 14 and a brake hydraulic pressure to a brake unit. The output port 16 is formed.

Reference numeral 17 denotes a plunger slidably accommodated in a cylinder hole 18 between the input port 15 and the output port 16 and having an upper end in the figure sealed by a cup seal 19 and a backup ring 20. The snap ring 21 is used to prevent disengagement, and the step portion between the large diameter portion and the small diameter portion of the cylinder hole 18 and the plunger 1 are prevented.
A seal 22 is interposed between the seal 22 and the seal 7.

Reference numeral 23 is a seat member provided so as to face the plunger 17, and is movable in the axial direction only between a step portion 24 and a snap ring 25 provided at a predetermined distance from the snap ring 21.

Reference numeral 26 is a push rod formed of a thermoplastic resin, one end of which is integrally fixed to the link arm 27 by thermal caulking, and the other end of which is opposed to the seat member 23 via a metal cup 28 having an elastic member 40 inside. It is arranged to. A return spring 29 is provided between the push rod 26 and the snap ring 25, and a proportioning spring 30 is provided between the cup 28 and the seat member 23. Reference numeral 31 is a dustproof boot interposed between the housing 13 and the push rod 26.

One end of the link arm 27 is supported so as to rotate about a fulcrum A, a sensor spring 33 is engaged with a spring guide 32 formed at the other end, and the other end of the sensor spring 33 is a spring of the vehicle. It is attached to a bracket 34 fixed below.

Then, the relative displacement between the sprung portion and the unsprung portion according to the vehicle load is converted into a load by the sensor spring 33, and the plunger 17 is pressed via the link arm 27 and the seat member 23 in proportion to the load. When the braking operation is performed in this state and the hydraulic pressure input from the input port 15 exceeds the pressure (split point) set by the pressing force on the plunger 5 according to the relative displacement of the vehicle top and bottom springs,
The plunger 17 moves the sheet member 23 to the upper side of the drawing, the liquid flow path is closed by the seal 22, and when the liquid pressure balance changes due to this closing, the liquid flow path is opened again, and this opening / closing operation is repeated. The liquid pressure is reduced and supplied to the output port 16. In this way
As shown in FIG. 2, the split point changes according to the pressing force applied to the plunger 5 according to the vehicle load, so that the braking force according to the lightness or weight of the vehicle load can be set.

In this way, the seat member 23 is interposed between the push rod 26 and the plunger 17, and the movement of the seat member 23 is restricted by the step portion 23 so as not to press the plunger 17 more than a predetermined stroke. Since the pressing force of the push rod 26 is not directly applied to the plunger 17 during non-braking, and the rigidity of the push rod 26 may be low, it is possible to reduce the size.

Further, the positional relationship between the backup ring 20, the seat member 23 and the snap ring 25 will be described in detail with reference to FIG. 3. The stroke of the plunger 17 that is operated by the brake fluid pressure during braking (equal to the stroke of the seat member 23). Is 1 and the thickness of the seal member 23 is W, the snap ring 25 is provided at a position separated from the step portion 24 by a distance of 1 + W. Further, assuming that the gap distance formed between the backup ring 20 and the seat member 23 when the seat member 23 contacts the step portion 24 and the plunger 17 during non-braking is 2, the fitting length of the backup ring 20 and the cylinder hole 18 is set. 3 was made longer than 1 + 2 (ie 3> 1 + 2). Therefore, the snap ring 21 comes off under some conditions and the backup ring 2
Even if 0 is pulled out from the cylinder hole 18, the sheet member 23 in contact with the snap ring 25 prevents the entire backup ring 20 from falling out of the cylinder hole 18, and the brake fluid is lost. Can be prevented.

[Advantages of the Invention] As described above, according to the present invention, the force of the push rod is prevented from being applied to the plunger through the seat member during non-braking, so that damage to the plunger can be prevented. Along with this, the plunger can be downsized.

Also, even if the first ring member comes off and the backup ring moves toward the seat member side, the movement of the backup ring is restricted by the second ring member and the entire ring does not fall out of the cylinder hole, so brake fluid leakage is prevented. The fail-safe function can be surely exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of an embodiment of the present invention, FIG. 2 is an explanatory view for explaining the operation of the embodiment, and FIG. 3 is a cross-sectional view of a main part for explaining a backup ring retaining structure in the embodiment FIG. 4 and FIG. 4 are sectional views of a conventional linkage type hydraulic control valve. Reference numerals in the figure: 13; housing 14; hydraulic control valve 15; input port 16; output port 17; plunger 18; cylinder hole 19; cup seal 20; backup ring 21; snap ring 23; seat member 24; step portion 25 Snap ring 26; Push rod 28; Metal cup 40; Elastic member

Claims (2)

[Scope of utility model registration request] 1. A push rod, which is integral with a rotatable link arm, presses a plunger in a housing according to a relative displacement between a sprung part and an unsprung part of a vehicle, and a master cylinder hydraulic pressure has a predetermined value during braking. In the linkage type hydraulic control valve for controlling the brake fluid pressure to the brake unit to be reduced by operating the plunger so that the fluid flow passage is closed, the movement of the push rod to the plunger side during non-braking is prevented. A linkage type hydraulic control valve, wherein a seat member that is stopped at a predetermined position by being locked with one end of the housing is interposed between the push rod and the plunger. 2. The linkage type hydraulic control valve according to claim 1, wherein a backup ring for retaining a cup seal for sealing between the plunger and the cylinder hole is provided at one end of the housing. A second ring member is provided at one end of the housing, the second ring member being locked to the ring member and locking when the seat member facing the plunger moves to a predetermined position on the push rod side and stopping the movement. Even if the first ring member comes off and the backup ring moves to the sheet member side,
Linkage type hydraulic control valve, wherein the backup ring length is set to a sufficient length so that the entire backup ring does not fall out of the cylinder hole when locked to the ring member.