JPH0238420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake pressure compensator controlled by vehicle load.

Huns Patent No. 1282714 discloses a brake pressure correction device controlled by the vehicle load. The device includes a control unit consisting of a push rod, a preload spring that exerts a set thrust on the push rod, and a control spring that applies a traction force on the push rod that varies in magnitude as an inverse function of the vehicle load. .

Although the compensating device described in the above-mentioned French patent ensures a limitation of brake pressure, the teaching of the invention can also be applied to a brake compensator that ensures a limitation of the increase in brake pressure.

This type of control unit requires the casing of the compensator to be installed in substantially the same direction as the direction of movement of the vehicle's suspension springs, and also has the disadvantage that such an installation is not necessarily possible in all vehicles. There is profit.

Also, as suggested in the French patent mentioned above, a control is provided so that the casing of the compensator can be placed in a direction different from the direction of movement of the suspension spring, for example in a direction substantially perpendicular to said direction. It is possible to use a reversing lever device between the spring and the push rod.

However, in such devices, the orientation of the control spring in a plane perpendicular to the axis of the casing is limited to approximately only one preferred direction. Therefore, if the compensator casing needs to be rotated about its axis for any reason, a newly designed casing is required to accommodate the reversing lever device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake pressure compensator which eliminates the above-mentioned drawbacks and is designed to be mounted in any direction on the sprung or unsprung part of a vehicle without requiring any modifications. It's about doing.

To achieve this objective, the present invention comprises a casing mounted on one of the sprung and unsprung parts of a vehicle and accommodating a compensation valve, a push rod connected to the compensation valve, and a push rod for biasing the compensation valve in one direction. a preload spring that applies a set pressing force to the push rod, and an annular bearing surface whose enlarged end is integrally formed with the casing by the action of the preload spring so as to extend coaxially with the said direction. a connecting member which is supported by a connecting member, one end of which is fixed to the other of the sprung and unsprung portions of the vehicle, and the other end of which is latched to a projecting end that projects from the casing of the connecting member, in the biasing direction of the preload spring. A brake pressure compensator is provided which is sensitive to the load of a vehicle, characterized in that it comprises a control spring extending in a substantially perpendicular direction.

According to the above configuration, the connecting member that transmits the control tractive force that changes depending on the load of the vehicle from the control spring to the push rod can rotate in any direction with respect to the annular seat surface of the casing through its enlarged end. There are no restrictions as to the orientation of the control spring in a plane perpendicular to the axis of the control spring, which provides an extremely large degree of freedom in the installation of the casing and the control spring in the sprung and unsprung parts of the vehicle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a brake pressure compensator 10 includes a casing 12 with an inlet orifice 14 and an outlet orifice 16. Inlet orifice 14 is connected to a source of pressurized fluid, such as a brake master cylinder (not shown), and outlet orifice 16 is connected to one or more brake actuators (not shown). Finally, the casing 12 is fixed on the sprung part of the vehicle, the chassis.

Although the internal structure of the casing 12 is not shown in detail in FIG. 1, FIG. 2 and the related description can be referred to.

At this stage of explanation, it will only be briefly stated that a compensation valve is mounted on the casing 12, that this valve is further controlled by a piston 18, and that one end 18a of the piston protrudes from the casing 12 to the outside. I'll keep it.

A control unit 20 is secured to the casing 12 and applies a force to the piston 18 that varies as a function of vehicle load.

The control unit 20 comprises a push rod 22 housed in a tubular housing 24, which is secured to the casing 12, for example by a screw connection. Preload spring 26
is interposed between the abutment surface 28 of the inwardly facing shoulder of the housing 24 and the abutment surface of the outwardly facing flange 30 of the push rod 22 to hold the push rod 22 and the piston 18 within the casing 12. Pressing in the pushing direction. pushyrod 2
2 has, at its end remote from the piston 18, an enlarged head 32 housed in a cavity 34 of an inverting device 36, which inverts the tubular housing 2.
It is supported on a planar support surface consisting of an annular seat 38 formed at the end of the 4.

The reversing device 36 includes an axial coupling member 40 with a control spring 4 extending substantially perpendicularly to the coupling member at its free end 40a.
2 is hooked.

The control spring 42 is connected at its other end to the unsprung portion of the vehicle in any suitable manner.

The control unit 20 therefore causes a preload thrust of a set magnitude to be applied to the push rod 22 by the preload spring 26 on the piston 18 and a vehicle thrust force applied by the spring 42 via the reversing device 36. A control force is applied whose components include a control traction force whose magnitude varies as an inverse function of the load.

Since the reversing device 36 is mounted on the casing by means of a swivel joint type articulation device, the orientation of the spring 42 in the plane perpendicular to the axis of the reversing device is ensured. This is a matter that could not be ensured with conventional lever devices when transmitting the force of the spring 42 to the push rod 22. This also allows for both the installation of the casing 12 on the vehicle's chassis and the positioning of the other end of the spring 42 in the unsprung portion of the vehicle.
This significantly expands the scope. In this embodiment, the swivel joint type is configured as a swivel joint with a planar bearing surface.

Furthermore, the initial setting of the preload spring 26 can be ensured independently by the manner in which the tubular housing 24 is screwed onto the casing 12. Similarly, the mounting of control spring 42 allows independent adjustment of this spring.

In the embodiment shown in FIG.
cooperates directly with the wheel cylinder 150.
All components of this correction device are substantially the same as those of the first embodiment and are designated by the same reference numerals.
Shown with 100 added.

In FIG. 2, the internal structure of the casing is shown in detail. That is, the casing 112 has a hole 152 therein, and an inlet orifice 114 is inserted into the hole.
and exit orifice 116 is open. A sleeve 154 is mounted between the inlet orifice 114 and the open end of the bore 152 and is held in place by a tubular housing 124. The piston 118 is stepped and the sleeve 1
A small diameter portion 118a that slides within the hole 118a slides within the hole 1
52, and a large diameter portion 118b that slides within the inner diameter portion 118b.

Piston 118 and bore 152 cooperate to define an inlet chamber 156 near inlet orifice 114 and an outlet chamber 158 near outlet orifice 116. Passage 16 provided within piston 118
0 connects the two chambers 156, 158, and a ball valve 162 is provided in the passageway 160 to control the flow of brake fluid therein. Stop member 16 mounted at the bottom of hole 152
4 is provided with a finger 166 which projects towards the ball of the valve 162 and is arranged to open said valve 162 when the piston moves towards the stop member 164.

In this embodiment, the correction device 110 cooperates directly with the wheel cylinder 150 in the following manner.
The casing 112 includes a second bore 168 substantially perpendicular to the bore 152, and two actuating pistons are slidably received at opposite ends of the bore 168 (only piston 170 is shown). It is shown). Working chamber 17 between these two pistons
4 is limited, and the same room has a direct exit orifice 116
is connected to. It is clear that this embodiment provides a particularly compact correction device and wheel cylinder unit.

In this embodiment, the casing of the compensator is fixed to the unsprung part of the vehicle and the control spring 1
The free end of 42 is connected to the chassis, which is the sprung portion of the vehicle. This type of attachment can of course be adopted in the first embodiment.

The correction devices shown in FIGS. 3 and 4 have substantially the same elements as in the correction devices of FIGS. 1 and 2 with the same reference numerals plus 200 and 300, respectively.

In FIG. 3, the compensator 210 is secured to the sprung portion of the vehicle and includes a housing 212 having an inlet orifice 214 and an outlet orifice 216, the inlet orifice 214 being connected to the vehicle's master cylinder (not shown). ), and the outlet orifice 216 is connected to a rear brake motor (not shown). A compensation valve 217 is housed within the housing 212 and is controlled by a piston 28 . One end 218a of the piston 218 projects to the outside of the housing 212.

Compensation valve 217 is substantially the same as the valve of FIG. 2 and will not be described in detail.

A control unit 220 is secured on the housing 212 and applies a force to the piston 218 that varies as a function of vehicle load.

As shown, control unit 220
includes a push rod 222 housed within a tubular housing 224 that is secured to casing 212 (eg, by a threaded connection). A preload spring 226 is interposed between an inwardly facing shoulder 228 of housing 224 and an outer flange 230 of push rod 222 to bias push rod 222 and piston 218 into casing 212. are doing.

In this embodiment, the push rod 222 itself constitutes an inverting device as follows. That is, flange 230 is supported on a planar support surface defined by an annular seat 238 within tubular housing 224, and push rod 222 has visible extension 240 as an axial coupling member. A control spring 242 is hooked to the free end 240a of the section and extends substantially perpendicularly to the push rod 222. The other end of the spring 242 is connected to an unsprung portion of the vehicle by an appropriate method not shown.

The control unit 220 loads the piston 218 with a push rod 2 by means of a preload spring 226.
22 and a control force resulting from the resultant of a setpoint axial preload thrust applied to 22 and an axial control traction force whose magnitude varies as an inverse function of the vehicle load. The above axial control traction force is
This is caused by the force of spring 242 acting on free end 240a of push rod 222 causing push rod 222 to rotate on support surface 238. At this time, since the push rod 222 is in contact with the piston 218 via the rounded protrusion 229, the force exerted by the push rod 222 on the piston 218 is always parallel to the axis of the piston.

Finally, the surface 231 of the flange 230 supported by the annular seat surface 238 is formed such that the ratio of the distances h and d is always constant, regardless of the rotation angle of the push rod. Here, the distance h is
Annular seat surface 238 and push rod end 240a
is the axial distance between the point at which the control spring 242 is hooked, and d is the axial distance between the control spring 242 and the point at which the control spring 242 is hooked;
From the point of contact between 22 and piston 218, surface 231
This is the radial distance to the point of contact between the annular seat surface 238 and the annular seat surface 238.

Further, an inwardly facing shoulder 228 supporting a preload spring 226 is connected to the tubular housing 224.
It should be noted that the ring 225 is formed on a ring 225 which is axially adjustable (e.g., by a threaded connection). This structure allows the initial setting of the preload spring 226 to be easily changed.

Compared to the previously described embodiments, this correction device can (i) reduce the size of the correction device in the axial direction, (ii) reduce the number of parts, and (iii) use the correction device described above. There are advantages such as simplifying assembly without losing the advantages obtained.

In FIG. 4, a correction device 310 is the device shown in FIG. 3 with the following modifications. That is,
Preload spring 326 is supported on push rod 322 via cup 344, with push rod 322 and cup 344 having two mutually aligned spherical bearing surfaces 346, 348.

An advantage of this construction is that it prevents twisting of the preload spring 326 when the push rod 322 rotates, especially since this rotation is in any direction.

In the case of the compensator 210 shown in FIG. 3, as the push rod 222 rotates, the preload force of the spring 226 acting on the rod changes as a function of the direction of rotation. The reason is that the rotation of this spring causes different deformations depending on the direction of rotation.

Conversely, in the compensator of FIG. 4, regardless of the direction of rotation of the push rod 322, the rotation of the push rod's spherical support surface 348 causes the cup 344 to remain in a parallel position, so that the preload spring 326 is substantially This results in compression in the axial direction.

[Brief explanation of drawings]

FIG. 1 is a side view showing a first embodiment of the brake pressure compensator according to the present invention, partially shown in longitudinal cross section, and FIG. 2 is a cross section showing a second embodiment of the brake pressure compensator according to the present invention. 3 is a sectional view showing a third embodiment of the brake pressure correction device according to the present invention, and FIG. 4 is a sectional view showing a fourth embodiment of the brake pressure correction device according to the invention. 10... Brake pressure compensator, 12... Casing, 14... Inlet orifice, 16... Outlet orifice, 18... Piston, 20... Control unit, 22... Push rod, 24... Tubular housing, 26... Preload spring, 28...
...Shoulder, 30...Flange, 36...Reversing device,
38... Annular seat surface, 40... Connection member, 42...
control spring.

Claims (1)

[Claims] 1. Casing 12, 24; 11 that is attached to one of the sprung and unsprung parts of the vehicle and accommodates the correction valve.
2,124; 212,224; 312,324
and a push rod 22; 2 connected to the compensation valve.
22; 322; a preload spring 26; 226; 326 for applying a set pressure force on the push rod to bias the compensator in one direction; and a preload spring generally extending coaxially with said direction. a connecting member 40; 240; 340 whose enlarged end is supported against an annular seating surface 38; 238; 338 formed integrally with the casing; A control spring 42; 142; 24 which is fixed and whose other end is engaged with a protruding end 40a; 240a;
2; 342,
Brake pressure compensator sensitive to vehicle load. 2. The enlarged ends of the push rod 22; 222; 322, the preload spring 26; 226; 326 and the connecting member 40; 240; 340 are attached to the casing 12; 112; 212; 338 and abutment surface 28 for one end of the preload spring; 228; 32
Tubular housing 24 forming 8; 12
4; 224; 324; 224; 324; 324; 324; 3. The push rod 22 has an abutment surface 30 for the other end of the preload spring 26 adjacent to the compensating valve and has a contact surface 30 for the other end of the preload spring 26 and a connecting member 4 at the opposite end.
3. The brake pressure compensator according to claim 2, further comprising a head 32 accommodated in a cavity 34 formed at the enlarged end of the brake pressure compensator. 4 Connecting member 240; 340 is the push rod 2
22; Consisting of an extension of 322, the connecting member 24
The enlarged end of 0; 340 is an annular seat surface 238; 338
consists of a radial flange 230; 330 having a surface 231; Claim 1, characterized in that the surface of the radial flange is shaped to keep the ratio h/d constant, given the radial distance between the contact point of the seat and the axis of the push rod. Brake pressure correction device according to item 2. 5 Push rod 322 is preload spring 3
a cup 34 forming an abutment surface for the other end of 26;
A spherical support surface 34 cooperating with a spherical support surface 348 of 4
Claim 4 characterized in that it has 6
Brake pressure compensation device as described in section. 6 The casing 112 is the unsprung portion 150 of the vehicle.
The brake pressure correction device according to any one of claims 1 to 5, characterized in that the device is mounted on a brake pressure correction device. 7 The casing 112 is the wheel cylinder 150
7. The brake pressure compensator according to claim 6, further comprising an outlet orifice (116) which is integral with the casing of the wheel cylinder and communicates with the inlet orifice of the wheel cylinder.