JPH07267062A - Load sensing proportioning valve - Google Patents

Abstract

PURPOSE:To inform abnormality to an operation room, and detect abnormality of a sensor spring by monitoring a condition of a lever to energize a repulsive load of the loading load detecting sensor spring to a plunger of a load sensing proportioning valve. CONSTITUTION:A primary side fluid chamber 16 on which master cylinder fluid pressure acts, a secondary side fluid chamber 17 connected to a rear wheel cylinder, a plunger 41 arranged in a differential pressure generating chamber 40, a valve body 34 and a built-in spring 46 are arranged in a housing 15. A sensor spring 51 rotatably supported in the vertical direction is arranged between it and an axle side member 70. A switch 80 is arranged in the housing 15, and an actuating piece 81 is constituted so as to separate from a part 66 to be detected when a lever 50 descends in rotation since the sensor spring 51 is broken. An alarm is actuated by this separation, and informs abnormality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load-sensing proportioning valve for controlling distribution of front wheel brake hydraulic pressure and rear wheel brake hydraulic pressure in a vehicle such as a truck in accordance with a load and pitching. .

[0002]

2. Description of the Related Art A load sensing proportioning valve mounted on a vehicle changes the ratio of the rear wheel brake hydraulic pressure to the front wheel brake hydraulic pressure (master cylinder hydraulic pressure) according to the vehicle load and the like. That is,
When the vehicle is braking, the larger the deceleration is, the more the front wheel load increases and the rear wheel load ratio decreases.Therefore, in the range where the braking force exceeds a predetermined value, the rear wheel brake fluid pressure increase rate is changed to the front wheel brake fluid pressure increase rate. By making the amount smaller than that, it is possible to approach the ideal brake fluid pressure distribution.

For example, a known load sensing proportioning valve 100 shown in FIG. 5 has a proportioning main body portion 102 having a valve body 101 built therein, a load sensing portion 10 having a lever 103 and a sensor spring 104.
It has 5. The housing 110 of the proportioning main body 102 is fixed to a member on the vehicle body side. The housing 110 has a primary-side fluid chamber where the master cylinder fluid pressure acts.
111 and a secondary side fluid chamber 112 connected to the rear wheel cylinder via the rear wheel brake pipe are provided, and the valve body 101 is provided between the primary side fluid chamber 111 and the secondary side fluid chamber 112. It is provided.

The valve body 101 is open until the brake fluid pressure acting on the fluid chambers 111 and 112 reaches a predetermined value.
Further, the plunger 116 is housed in the differential pressure generating chamber 115 provided in the housing 110. The plunger 116 is interlocked with the valve body 101 and is biased by a built-in spring 117 in a direction to open the valve body 101, and the liquid chambers 111, 11
When the brake fluid pressure acting on 2 exceeds a predetermined value, the valve body 101 is displaced in the closing direction due to the difference in pressure receiving area.

Therefore, the proportioning main body 102
Until the braking force (brake hydraulic pressure) of the vehicle reaches a predetermined value, the brake hydraulic pressure generated in the master cylinder is sent as it is to the secondary hydraulic chamber 112 via the primary hydraulic chamber 111, so Equivalent brake fluid pressure acts on the wheels.

When the brake fluid pressure exceeds a predetermined value,
When the plunger 116 is pushed down against the resilience of the built-in spring 117 and the valve body 101 moves in the closing direction, and the brake fluid pressure rises further, the plunger 116 is pushed by the differential pressure according to the difference in the pressure receiving area of the plunger 116. Since the valve body 101 is driven and moves in the valve opening direction, the brake fluid pressure introduced into the primary side fluid chamber 111 is reduced at a constant rate, and the secondary side fluid chamber is reduced.
Sent to 112. Therefore, as shown by the solid line in FIG. 6, for example, a polygonal line-shaped characteristic is obtained in which the increase rate of the rear wheel brake fluid pressure becomes smaller than the front wheel brake fluid pressure increase rate at a specific fluid pressure. To be

On the other hand, the lever 10 of the load sensing unit 105
3 is provided so as to be rotatable in the vertical direction by a shaft 120, and when the lever 103 is raised, the plunger 11
It is designed to push up 6. Sensor spring 104
Is provided between the tip of the lever 103 and the member 121 on the axle side, and urges the lever 103 in the direction of raising it.

In this case, when the loaded load increases, the vehicle body is displaced in the direction of sinking, so that the housing 110 is lowered with respect to the member 121 on the axle side. When the amount of bending of the sensor spring 104 increases in this way, the lever 10
The repulsive load in the direction of pushing up 3 is increased, and this repulsive load is added to the repulsive load of the built-in spring 117 to push up the plunger 116.

For this reason, when the load is large, as shown by the broken line in FIG. 6, the timing when the rear wheel brake fluid pressure reduction distribution starts is delayed and the rear wheel brake fluid pressure is maintained properly. To be In other words, the characteristic is that the time when the reduced pressure distribution starts (the starting point of the polygonal line) moves in the direction of arrow A in FIG. 6 as the load increases.

[0010]

In the above-mentioned load-sensing proportioning valve 100, if the sensor spring 104 becomes abnormal such as broken or disengaged, a predetermined brake fluid pressure cannot be distributed. Measures have been taken to reduce the hydraulic pressure to a certain rate, or to increase the rear-wheel brake hydraulic pressure to a certain rate in some vehicles. In any case, since the brake fluid pressure distribution between the front wheels and the rear wheels may deviate from an ideal value when the sensor spring is broken, normal traveling is not hindered, but it is desired to know the abnormality of the sensor spring at an early stage.

Therefore, an object of the present invention is to enable an occupant to be notified of an abnormality that has occurred in a sensor spring, so that the braking force can be exerted under a normal brake fluid pressure distribution.

[0012]

A load sensing proportioning valve of the present invention developed to achieve the above-mentioned object is a housing fixed to the vehicle body side, and a master cylinder hydraulic pressure provided on the housing acts. A primary side liquid chamber and a secondary side liquid chamber connected to the rear wheel cylinder; and the primary side liquid chamber and the secondary side liquid chamber provided between the primary side liquid chamber and the secondary side liquid chamber. A valve body for controlling the opening and closing of the state of communication with the chamber; and a master cylinder fluid that is provided in the housing and is urged in the direction of opening the valve body by interlocking with the valve body and a built-in spring. When the pressure exceeds a predetermined value, the valve body is displaced in the closing direction to reduce the increase rate of the rear wheel cylinder hydraulic pressure with respect to the master cylinder hydraulic pressure. Provided between the lever, which is rotatably supported in the up-down direction in the vertical direction and displaces the plunger in the direction to open the valve body when in the raised position, and the other end of the lever and a member on the axle side. A sensor spring for increasing the urging force in the direction of raising the lever as the load capacity of the vehicle increases, a detection means for outputting an electric signal when the lever is rotated and lowered by a predetermined angle or more; And an informing means which is provided on the driver's cab side and operates based on the output signal of the detecting means.

[0013]

According to the load sensing proportioning valve of the present invention, the brake fluid pressure generated in the master cylinder passes through the primary side fluid chamber as it is to the secondary side until the master cylinder fluid pressure reaches a predetermined value, like the conventional one. Since it is sent to the fluid chamber, the same brake fluid pressure acts on the front and rear wheels.
When the master cylinder hydraulic pressure exceeds a predetermined value, the plunger moves against the resilience of the built-in spring and sensor spring, and the valve body moves toward the closing direction.When the master cylinder hydraulic pressure rises further, the pressure receiving area of the plunger The plunger is driven by the pressure difference according to the difference between the two, and the valve element moves in the valve opening direction. Therefore, the brake pressure introduced into the primary side liquid chamber is reduced at a constant rate and sent out to the secondary side liquid chamber.

Further, the deflection amount of the sensor spring increases as the loaded load increases, and the repulsive load of the sensor spring corresponding to the loaded load is added to the repulsive load of the built-in spring to urge the plunger. When it is large, the time when the rear wheel brake fluid pressure reduction distribution starts is delayed.

When a stone or any obstacle that has been bounced up from the road surface while the vehicle is traveling hits the sensor spring and the sensor spring is bent or disengaged so that the lever is displaced in the direction in which the lever hangs down, a detecting means for monitoring the state of the lever. Is activated to activate the warning means in the cab, turn on or blink the warning light, or generate an alarm sound such as a buzzer.Therefore, it is possible to immediately know that the sensor spring is abnormal even while traveling. it can.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The load sensing proportioning valve 10 shown in FIG. 1 is provided with a proportioning main body portion 11 and a load sensing portion 12 as in the conventional one.

The proportioning body 11 has a housing 15 fixed to the vehicle body side. The housing 15 is provided with a primary side liquid chamber 16 and a secondary side liquid chamber 17. A brake pipe 21 communicating with the master cylinder is connected to the connection port 20 of the primary side fluid chamber 16 so that front wheel brake fluid pressure acts on the primary side fluid chamber 16. A rear wheel brake pipe 23 communicating with the rear wheel cylinder is connected to the connection port 22 of the secondary side liquid chamber 17.

As shown in the enlarged view of FIG. 2, the primary side liquid chamber 1
6 and the secondary side liquid chamber 17, a communication hole 30 and a valve chamber 31.
And a secondary side inflow chamber 32 is provided. The valve chamber 31 is provided with a valve seat 33, a valve body 34 that contacts and separates from the valve seat 33, a seat spring 35 that pushes the valve body 34 toward the valve seat 33, and the like.

Further, a differential pressure generating chamber 40 communicating with the primary side liquid chamber 16 is provided. A plunger 41 is housed in the differential pressure generating chamber 40. The plunger 41 is vertically movable, and the large diameter portion 42 of the plunger 41 is inserted into the secondary side inflow chamber 32. The small diameter portion 43 of the plunger 41 penetrates the differential pressure generating chamber 40 in the vertical direction, and the lower end 44 of the plunger 41 projects to the lower surface side of the cap member 45. The plunger 41 is biased by a built-in spring 46 in a direction to open the valve element 34.

On the other hand, the load sensing section 12 includes a lever 50 extending in a generally horizontal direction and a sensor spring 5.
1 is provided. The base portion 52 of the lever 50 is supported on the lower portion of the housing 15 by a shaft 53 so that the lever 50 can rotate in the vertical direction. A roller 54 is provided at an intermediate portion in the length direction of the lever 50, and the lower end 44 of the plunger 41 faces the upper side of the roller 54.

The lower part of the housing 15 and the base side of the lever 50 are covered with a cover 60 having rubber-like elasticity. A collar-shaped stopper wall 61 is provided on the upper portion of the cover 60. The stopper wall 61 is fixed to the housing 15.

An adjusting screw 65 extending vertically is provided at the tip of the lever 50. The upper end of the adjusting screw 65 faces the lower surface of the stopper wall 61, and the rising end (upper limit position in the arrow F direction) of the lever 50 is regulated according to the amount of advance of the adjusting screw 65 (protruding height of the upper end face). It is supposed to be done. Further, a detected portion 66 that rises in an L shape is provided at the tip of the lever 50. The detected portion 66 is fixed to the lever 50 using a lock nut 67 screwed to the adjusting screw 65.

One end of a sensor spring 51 is connected to the tip of the lever 50. As shown in FIG. 1, the sensor spring 51 is made of strip-shaped spring steel,
It extends toward the member 70 on the axle side. The sensor spring 51 of this embodiment has an adjusting screw 65 and a nut 67.
Since it is fastened together with the detected portion 66 by utilizing, the number of parts required for fixing is small, and the mounting work is easy.

A link 71 rising in the vertical direction is fixed to the member 70 on the axle side, and the male spring portion 72 connected to the upper end side of the link 71 is connected to the sensor spring 5.
The other end side tip portion 73 of 1 is fixed by a nut 74. By changing the screwing position of the nut 74, the height of the tip portion 73 of the sensor spring 51 can be variably set. The length of the sensor spring 51 is, for example, about 50 cm, but the length, shape, spring constant and the like are appropriately selected according to the type of vehicle.

In the load sensing section 12 having the above-mentioned sensor spring 51, the height of the housing 15 is relatively lowered due to the sinking of the vehicle body when the load is large, so that the amount of deflection (biasing force) of the sensor spring 51 is increased.
Grows larger. Since the position of the housing 15 is high when the load is small or when the load is empty, the sensor spring 5
The bending amount of 1 becomes small. In this way, the amount of flexure of the sensor spring 51 changes according to the size of the loaded load, and the repulsive load of the sensor spring 51 changes, so that the biasing force that pushes up the lever 50 changes.

A switch 80 as an example of a detecting means is provided on the side surface of the housing 15. The switch 80 outputs an electric signal according to the position of the lever 50, and a known limit switch or the like can be used. The operator 81 of the switch 80 is the detected part 6
6, the detection target portion 66 separates from the operator 81 when the lever 50 pivots and descends beyond a predetermined angle, so that the contact circuit 8 inside the switch 80
2 is supposed to close. The switch 80 is
An optical switch using an optical sensor or a proximity switch using a magnetic sensor may be adopted instead of the limit switch.

As shown in FIG. 1, the switch 80 is electrically connected via a harness 85 to a vehicle-mounted battery 86 and a notification device 87 as an example of notification means. Alarm 87
Is provided at a position where an occupant can know it, such as an instrument panel in the cab of a vehicle.

An example of the alarm 87 is a status indicator lamp such as a warning lamp that is turned on or blinks by a current flowing when the switch 80 is closed, but in some cases, an alarm sound generator such as a buzzer may be used, or a lamp. And a warning sound generator may be combined.

Next, the operation of the load sensing proportioning valve 10 having the above structure will be described. The brake fluid pressure generated in the master cylinder during vehicle braking is introduced into the primary side fluid chamber 16. At this time, until the brake hydraulic pressure reaches a predetermined value, the plunger 41 is pushed up by the repulsive load of the built-in spring 46 as shown in FIG. 2, and the valve body 34 is also raised accordingly. In this case, the brake fluid introduced into the primary side fluid chamber 16 remains as it is in the communication hole 30.
Since it is sent to the secondary side fluid chamber 17 via the valve chamber 31 and the inflow chamber 32, the same brake fluid pressure acts on the front wheels and the rear wheels.

When the brake fluid pressure in the primary side fluid chamber 16 and the secondary side fluid chamber 17 increases due to the increase in the braking force, the pressure in the valve chamber 31 and the inflow chamber 32 also increases, and the pressure reaches a predetermined value. When the repulsive load of the built-in spring 46 and the pushing force of the lever 50 are overcome, the valve body 34 is displaced in the valve closing direction and the plunger 41 is lowered. When the brake fluid pressure becomes higher than that, the large diameter portion 4 of the plunger 41
The differential pressure corresponding to the difference between the pressure receiving areas of 2 and the small diameter portion 43 acts in the direction of opening the plunger 41 and the valve body 34, so that the brake fluid pressure reduced at a rate corresponding to the differential pressure is generated in the valve chamber 31. It comes to flow into the secondary side liquid chamber 17 through the inflow chamber 32. Therefore, as shown in FIG. 6, a polygonal line-shaped characteristic is obtained in which the increase rate of the rear wheel brake hydraulic pressure is smaller than the increase rate of the front wheel brake hydraulic pressure at a specific hydraulic pressure.

On the other hand, since the amount of deflection of the sensor spring 51 increases as the loaded load increases, the repulsive load of the sensor spring 51 increases as the loaded load increases and is added to the repulsive load of the built-in spring 46, resulting in a larger force. Then, the plunger 41 is pushed up. For this reason, when the load becomes large, the time when the reduction distribution of the rear wheel brake hydraulic pressure starts is delayed as shown by the broken line in FIG. 6, and the rear wheel brake hydraulic pressure is maintained appropriately.

For some reason, the sensor spring 5
When 1 is broken or the sensor spring 51 is disengaged, the repulsive load of the sensor spring 51, which has raised the lever 50 until then, does not act on the plunger 41.
As shown in FIG. 5, the lever 50 pivots down about the shaft 53 due to the weight of the lever 50 and the weight of the sensor spring 51.

As a result, the operator 81 of the switch 80 separates from the detected portion 66, the contact circuit 82 closes, and a current flows through the alarm 87, whereby the alarm 87 is released.
Makes an alarm action. Therefore, the occupant is notified that the sensor spring 51 is abnormal even while the vehicle is traveling.

In this embodiment, since the sensor spring 51 extends horizontally from the tip side of the lever 50,
When the sensor spring 51 is broken, the weight of the lever 50 and the weight of the sensor spring 51 act as a moment in the direction in which the lever 50 is rotated and lowered. Therefore, the lever 50
Can be reliably lowered, and the switch 80 can be reliably operated.

When the sensor spring 51 is broken, the force for pushing up the plunger 41 is only the built-in spring 46. Therefore, for example, as shown by the chain double-dashed line in FIG. Become. In this case, there is no hindrance to normal traveling, but by operating the alarm 87, it is possible to appropriately determine when to replace the sensor spring 51.

In the above embodiment, the switch 80 is provided on the ordinary housing 15 and the detected portion 66 is provided on the lever 50.
Is provided and the alarm 87 is added, so that the implementation is easy and the cost is low.

[0037]

According to the present invention, an occupant can immediately recognize an abnormality occurring in the sensor spring even while the vehicle is traveling, and the distribution ratio of the front wheel brake fluid pressure and the rear wheel brake fluid pressure is in a normal state. Vehicles can be operated while checking them at all times, improving safety.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an entire load sensing proportioning valve showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a part of the load sensing proportioning valve shown in FIG.

FIG. 3 is a cross-sectional view of the load sensing proportioning valve shown in FIG. 1 in a state where the valve body is closed.

FIG. 4 is a cross-sectional view of the load sensing proportioning valve shown in FIG. 1 in a state where the lever is lowered.

FIG. 5 is a cross-sectional view of a conventional load sensing proportioning valve.

FIG. 6 is a diagram showing a hydraulic pressure distribution characteristic of a load sensing proportioning valve.

[Explanation of symbols]

 10 ... Load sensing proportioning valve 15 ... Housing 16 ... Primary side liquid chamber 17 ... Secondary side liquid chamber 34 ... Valve body 40 ... Differential pressure generating chamber 41 ... Plunger 46 ... Built-in spring 50 ... Lever 51 ... Sensor spring 70 ... Axle Side member 80 ... Detection means (switch) 87 ... Notification means (report device)

Claims (4)

[Claims] 1. A housing fixed to a vehicle body, a primary side liquid chamber provided in the housing and acted by a master cylinder hydraulic pressure, and a secondary side liquid chamber connected to a rear wheel cylinder, and the primary side liquid. A valve body which is provided between the chamber and the secondary side liquid chamber and controls opening and closing of the communication state between the primary side liquid chamber and the secondary side liquid chamber, and the valve body which is provided in the housing When the master cylinder fluid pressure exceeds a predetermined value, the valve body is displaced in the direction to close the valve body by a built-in spring and is urged by a built-in spring to move the rear cylinder against the master cylinder fluid pressure. A plunger that reduces the rate of increase in the wheel cylinder hydraulic pressure; and a plunger that opens the valve body when one end side is supported by the housing in a vertically rotatable manner and is in a raised position. A lever that displaces the lever, a sensor spring that is provided between the other end of the lever and a member on the axle side, and that increases the urging force in the direction of raising the lever as the vehicle load increases. A detection means for outputting an electric signal when the lever is rotated and lowered by a predetermined angle or more; and a notification means provided on the driver's cab side of the vehicle and operated based on the output signal of the detection means. Characteristic load sensing proportioning valve. 2. The detecting means is a switch having an operator that separates from the detected portion of the lever when the sensor spring is broken and the lever hangs down, and the inside of the switch when the operator separates from the detected portion. The load sensing proportioning valve according to claim 1, wherein a contact is closed to energize the informing means. 3. The load sensing proportioning valve according to claim 1, wherein said informing means is a warning light which is turned on or blinks when the switch is closed. 4. The load-sensing proportioning valve according to claim 1, wherein the informing means is an alarm sound generator that sounds when the switch is closed.