JPH0328059A - Control device for load sensing valve - Google Patents

Abstract

PURPOSE:To give a proper fold point liquid pressure and establish the ideal characteristic with four-wheel simultaneous lock by putting a solenoid valve in communication or shutting it off under control on the basis of the result from comparison of the valve given by a master cylinder liquid pressure sensing means with the corrected fold point liquid pressure value. CONSTITUTION:A control device for a load sensing valve according to the present invention includes a master cylinder liquid pressure sensing means 15, brake switch SW, load calculating means 22, fundamental fold point liquid pressure setting means 18, memory device 23, and car body deceleration sensing means 16. The fold point liquid pressure correction amount (e) is calculated by a fold point liquid pressure correction amount calculating means 19 from the value P given by the mentioned master cylinder liquid pressure sensing means 15 and the valve (g) given by the car body deceleration sensing means 16, while the fundamental fold point liquid pressure value (a) of the memory device 23 is corrected with the fold point liquid pressure correction amount (e), and a corrected fold point liquid pressure value A is determined by a correcting means 20. This corrected fold point liquid pressure value A is compared with the value P given by the master cylinder liquid pressure sensing means 15, and on the basis of the result from this comparison a solenoid valve 12 is put in communication or shut off by a comparing means 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a load sensing valve in a vehicle brake.

[Conventional technology]

The load sensing valve is installed in the brake fluid pressure circuit between the master cylinder and the wheel cylinder, and is used to adjust the fluid pressure control start pressure ( This is a blow-off valve that changes the turning point) and has the function of preventing early locking of the rear wheels when the load is reduced.

As a conventional load sensing valve control device, there is one disclosed in, for example, Japanese Patent Laid-Open No. 105862/1983. This load sensing valve control device includes a load sensor that detects the live load of the vehicle and outputs a load signal representing the live load, and a deceleration signal that detects the deceleration of the vehicle and represents the deceleration. The load signal is determined based on a predetermined constant relationship between the deceleration sensor that outputs the deceleration sensor, the flashing speed at which the brake fluid pressure supplied to the rear wheel brakes should start to be suppressed, and the vehicle's carrying load. a master cylinder; The hydraulic pressure control valve is inserted into a fluid circuit connecting the rear wheel brake, and suppresses the brake hydraulic pressure supplied from the master cylinder to the rear wheel brake in accordance with the suppression signal.

[Intelligence B that the invention attempts to solve] However, in this type of conventional load sensing valve control device, the turn-off speed corresponding to the load is determined, and when the deceleration of the vehicle exceeds the turn-off speed, the master cylinder supplies the signal to the rear wheel brake. Since the system was designed to suppress the brake fluid pressure that is applied to the vehicle, there is a problem in that deceleration and brake fluid pressure cannot be made to correspond well. For example, when driving with a high friction coefficient of the lining or pad and depressing the brake pedal to produce a predetermined deceleration, that is, a flashing speed, if a suppression signal is output, if the brake pedal depression force is large, the If the brake fluid pressure supplied to the rear wheel brakes has already increased and the corner fluid pressure is set high, and conversely the brake pedal depression force is small, the brake fluid pressure supplied to the rear wheel brakes will increase. It is set low. In addition, if a load sensor that detects the vehicle's live load is one that calculates the live load from the amount of displacement between the sprung mass and unsprung mass of the vehicle, the amount of displacement between the sprung mass and unsprung mass will be constant during braking. First, it was not possible to determine the accurate m load, and as a result, inappropriate braking fluid pressure was applied, making it impossible to provide the ideal characteristics of four-wheel simultaneous locking. [Means to solve the problem]

The present invention was made in view of such conventional technical problems, and consists of a master cylinder that generates pressurized fluid during braking operation, and an inflow port that communicates with the fluid chamber of the master cylinder. , a cylinder body having an outflow port communicating with the rear wheel cylinder; a first liquid chamber slidably inserted into the internal space of the cylinder body and communicating with the inflow port; A piston that opens and closes a valve provided between the two liquid chambers according to the liquid pressure acting on the difference in pressure receiving area, and a blown-off spring that opens and opens the valve. A power piston that biases the piston, a containment chamber that is supplied with brake fluid that biases the power piston, and a fluid passageway that supplies brake fluid to the containment chamber, and communicates with the fluid passageway. or a control device for a load sensing valve comprising a solenoid valve that shuts off, a master cylinder hydraulic pressure detection means, a brake detection means for detecting a braking operating state or a non-braking operating state, a live load calculation means for calculating a live load from the amount of displacement between the sprung and unsprung parts; and a basic corner point hydraulic pressure setting means for calculating a basic corner point hydraulic pressure value according to a set value of the live load calculation means. , a storage device for storing the basic corner point hydraulic pressure value, a vehicle deceleration detection means for detecting vehicle deceleration in a braking operation state, a detected value of the master cylinder hydraulic pressure detection means, and the vehicle deceleration detection. a corner point hydraulic pressure correction amount calculation means for calculating a corner point hydraulic pressure correction amount from the detection value of the means; A correction means for determining a corner point hydraulic pressure value compares the corrected corner point hydraulic pressure value with a detection value of the master cylinder hydraulic pressure detection means, and controls the solenoid valve to open or shut off based on the comparison result. This is a load sensing valve control device equipped with a comparison means. [Operation] Accordingly, in the load sensing valve, when the brake pedal is depressed, the brake fluid in the fluid chamber of the master cylinder flows into the first fluid chamber from the inflow port of the cylinder body, and the valve in the open state and the second fluid chamber It is then supplied to the rear wheel cylinder to generate braking force. When the hydraulic pressure rises and reaches a turning point, the piston slides due to the hydraulic pressure acting on the difference in the pressure receiving area, and the first liquid chamber and the second liquid chamber are shut off by a valve, and then a predetermined ratio is reached. The system supplies reduced pressure brake fluid to the rear wheel cylinders to prevent the rear wheels from locking up early. The hydraulic pressure in the rear wheel cylinders that takes care of this turning point depends on the hydraulic pressure supplied to the containment chamber, and can be changed by connecting or shutting off the solenoid valve interposed in the piping that supplies the brake fluid. can do.

In this control device using such a load sensing valve, the brake detecting means detects whether braking is in operation or not, and when the brake is not in operation, the load is calculated using the displacement between the upper and lower parts of the spring. Determine the live load by means. The set value of the live load calculating means is supplied to the basic corner point hydraulic pressure setting means to obtain a standard basic corner point hydraulic pressure value corresponding to the live load.

This basic corner point hydraulic pressure value is temporarily stored in the storage device.

The braking operation state is detected by the brake detection means, and
When the solenoid valve is in communication, the corner point hydraulic pressure correction amount is calculated by the corner point hydraulic pressure correction amount calculation means using the detected value of the vehicle body deceleration detection means and the detected value of the master cylinder hydraulic pressure detection means. . Further, the correction means corrects the basic turning point hydraulic pressure value using the basic turning point command pressure value stored in the storage device,
Find the corrected corner fluid pressure value.

Next, the corrected corner hydraulic pressure value after the correction and the detected value of the master cylinder hydraulic pressure detection means are compared by the comparison means, and the detected value of the master cylinder hydraulic pressure detection means is higher than the corrected corner hydraulic pressure value. If the pressure exceeds this value, the solenoid valve is shut off and the brake fluid corresponding to the ideal corrected corner fluid pressure value is contained in the containment chamber. On the other hand, if the solenoid valve has already been controlled to shut off, but the detected value of the master cylinder hydraulic pressure detection means is smaller than the corrected corner hydraulic pressure value, there is no need to control the brake hydraulic pressure in the containment chamber. , connect the solenoid valve. In this way, the pressure in the containment chamber is set to the appropriate turning point fluid pressure according to the vehicle's carrying load, so the load sensing valve is alerted to the appropriate turning point. [Embodiment 3] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the arrangement of the components of the present invention, and FIG. 2 shows the arrangement of the components of an embodiment of the invention.

In FIG. 2, reference numeral 1 designates a tandem-type master cylinder, and when the brake pedal 2 is depressed, pressurized fluid in the front wheel side fluid chamber 1a is supplied to each front wheel cylinder of a pair of front wheels (not shown) via piping 29. Also, the rear wheel side liquid chamber 1
The pressure fluid b is supplied to the pair of rear wheel cylinders 4 of the rear wheels 3 via piping 28, and each generates a braking force. Here, the rear wheel cylinder 4 is a drum brake wheel cylinder or a disc brake cylinder.

A load sensing valve 1l in which a solenoid valve 13 is incorporated into a hydraulic pressure modulator 12 is interposed in a pipe 28 connected to the rear wheel cylinder 4. The hydraulic pressure modulator l2 is connected to the piping 2
An inflow port 31 connected to the rear wheel liquid chamber lb side of the cylinder body 8 and an outflow port 32 connected to the rear wheel cylinder 4 side are formed on the third cylinder body, and the piston 30 is inserted into the internal space of the cylinder body 38. It is slidably inserted. This cylinder body 38 and piston 3o have both ports 31, 3
A first liquid chamber 33 and a second liquid chamber 34 communicate with each other, and a valve 35 (valve seat 35B and valve seat 35a) between both liquid chambers 33 and
A valve body 35b) mounted on the piston 30 is provided so as to sit on the piston 30 and shut off both liquid chambers 33 and 34. 45
is a spring. The cylinder body 38 also includes a power piston 41 that is biased by a return spring 39 and a provisioning spring 40 that biases the piston 30 and is slidably fitted into the cylinder body 38, and a containment chamber 4.
2 and the inflow port 3l is the first ? & room 33
, a containment chamber 42 via a liquid passage 36 having a valve body housing space 43 in the middle for housing a valve body 13c to be described later.
The brake fluid having the same pressure as the rear wheel side fluid chamber 1b of the master cylinder 1 is supplied to the containment chamber 42. The electromagnetic valve 13 disposed in the valve body housing space 43 is an on-off valve having a solenoid 13a and a spring 13b, and the valve body 13c is in one normal position biased by the spring 13b in the valve body housing space 43. The valve body 13c is released from seating on the valve seat 13d, and brake fluid is supplied to the containment chamber 42, and the valve body 13c is seated on the valve seat 13d in the other position where it is energized by the solenoid 13a.
Contains brake fluid. Thus, when the brake pedal 2 is depressed, the load sensing valve 11 causes the brake fluid in the rear wheel side fluid chamber 1b of the master cylinder 1 to flow into the inflow port 3 of the cylinder body 38.
1 flows into the first liquid chamber 33, passes through the open valve 35 and the second liquid chamber 34, and is supplied to the rear wheel cylinder 4 to generate braking force. When the fluid pressure rises and reaches the corner fluid pressure, the piston 30 slides due to the fluid pressure acting on the difference in pressure receiving area, and the first fluid chamber 33 and the second fluid chamber 34 are shut off by the valve 35. Then, brake fluid whose pressure has been reduced at a predetermined ratio is supplied to the rear wheel cylinder 4 to prevent the rear wheels from locking up early. The hydraulic pressure in the rear wheel cylinder 4 that generates this turning point depends on the hydraulic pressure supplied to the containment chamber 42, and the hydraulic pressure in the rear wheel cylinder 4 that generates this turning point depends on the hydraulic pressure supplied to the containment chamber 42.・Can be changed by blocking. 44 is a microcomputer, an ink face,
It has a microprocessor and a memory, and has a basic corner point hydraulic pressure setting means as shown in FIG.
, correction 1,000 steps 20, comparison 1,000 steps 21, live load calculation means 22
and functions as a storage device 23. As shown in FIG. 2, the interface of this microcomputer 44 includes a solenoid 13a of the electromagnetic valve 13, and a brake switch which is a brake detection means for detecting whether or not the brake pedal 2 is depressed, that is, whether braking is activated or not. S
W1 Master cylinder hydraulic pressure detection stage 15 for detecting the pressure P of the rear wheel side liquid chamber lb of the master cylinder 1, the vehicle body 2
6 is connected to a vehicle deceleration detecting means 16 and a displacement meter 24 for determining the amount of displacement between the sprung and unsprung portions of the vehicle. The displacement meter 24 measures the amount of relative displacement between the vehicle body 26, which is located above the spring 25 of the vehicle suspension, and the axle tube 27, which is located below the spring 25, based on the brake pedal 2.
This is determined in a non-braking state where the brake pedal is not pressed, such as an electric micrometer. The detected value as an analog signal of this displacement meter 24 is converted into a digital signal by an A/D converter (not shown) and sent to a microcomputer 44.
As shown in Figure 1, the live load calculation stage 2
In step 2, the current (non-braking operating state, preferably non-travelling state) live load is determined. Next, the setting value of the live load calculating means 22 is supplied to the basic corner hydraulic pressure setting means 18, and the set value corresponds to the corner hydraulic pressure value corresponding to the carrying load in a state where the lining or pad has a standard friction coefficient. Find the basic corner point liquid pressure value a. This basic corner point liquid pressure value a is stored in the storage device 23.
Let it be memorized once. When the vehicle is running and the brake pedal 2 is depressed and the brake switch SW is turned on, the vehicle deceleration detecting means 16 detects the vehicle deceleration g. Next, using the detected value g of the vehicle body deceleration detection means and the detected value P of the master cylinder hydraulic pressure detection stage 15, the corner point hydraulic pressure correction amount e is calculated in the corner point hydraulic pressure correction amount calculation stage 19. do.

Using this corner point hydraulic pressure correction i1e, the standard basic corner point hydraulic pressure value a stored in the storage device 23 is corrected in the correction means 20 to obtain a corrected corner point hydraulic pressure value A. This corrected corner point hydraulic pressure value A after correction is compared with the detection value P of the master cylinder hydraulic pressure detection stage 15, and based on the comparison result,
An electric signal for controlling communication or disconnection of the electromagnetic valve 13 is sent from the comparison stage 2l. However, this solenoid valve l3 is normally biased by the spring 13b and in a communicating state, and when an electrical fault occurs, uncontrolled brake fluid is supplied to the rear wheel cylinder 4. This makes it fail-safe. In addition, vehicle body deceleration detection means l
Reference numeral 6 includes a G sensor or the like for detecting vehicle deceleration, and master cylinder hydraulic pressure detection means 15 includes a pressure sensor or the like. The detected values as analog signals of the 1,000-stage vehicle deceleration detection l6 and the 1,000-stage master cylinder hydraulic pressure detection l5 are also converted into digital signals by an A/D converter (not shown).

The control device for such a load sensing valve 1l is as follows:
According to the flowchart shown in FIG. 3, control is performed as follows. First, as an initial step, it is determined in step (2) whether the brake pedal 2 is depressed or not, that is, whether the brake switch SW is turned on. The amount of displacement between the upper and lower parts of the spring is detected by the displacement meter 24 (step ■), this detected value is supplied to the microcomputer 44, and the live load calculation stage 22 is operated! Find the loading load (step ■). Based on the calculated value of the live load calculation stage 22, the standard basic corner fluid pressure (aa) corresponding to the live load is determined from various corner fluid pressure values stored in advance in the ROM of the microcomputer 44. Step (2), this basic corner point hydraulic pressure {1a is temporarily stored in the storage device 23 of the microcomputer 44 in step (2). As shown in FIG. 4, as the amount of displacement between the upper and lower parts of the spring increases, that is, the load increases, the basic corner point hydraulic pressure value a also gradually increases.

Next, when the brake switch SW is turned on, the process moves to step 2, and it is determined whether the solenoid 13a of the solenoid valve 13 is on. If the solenoid 13a is OFF, the process proceeds to step 2, and the vehicle body deceleration is detected. The detected value of the means 16 is read, and further the detected value P of the master cylinder hydraulic pressure detecting means 15 is read in step (3). Thereafter, the process moves to step (2), and using the detection value g of the vehicle body deceleration detection means 16 and the detection value P of the master cylinder hydraulic pressure detection stage 15, the corner point hydraulic pressure is determined by the corner point hydraulic pressure correction amount calculation means 19. Calculate the correction amount e. This corner hydraulic pressure correction 51e is a value that changes depending on the magnitude of the friction coefficient of the lining or pad, and as the value of deceleration g/master cylinder hydraulic pressure P shown in FIG. The coefficient of friction of the pad increases. If the friction coefficient of the lining or pad is large and a large deceleration g can be obtained with the master cylinder hydraulic pressure P lower than the basic corner hydraulic pressure value a, the corner hydraulic pressure correction i1e
Gradually make it smaller and make it a negative number.

In step [phase], the storage device 23 is
Using the readout of the basic corner hydraulic pressure a-t- stored in and the corner hydraulic pressure correction i1e, the basic corner hydraulic pressure value a is corrected in the correction stage 20, and the corrected corner hydraulic pressure value A is Find (Step 0). Next, the process moves to step @, where the corrected corner hydraulic pressure value A after the correction and the detection value P of the master cylinder hydraulic pressure detection means 15 are compared at the comparison stage 21, and the master cylinder hydraulic pressure detection unit When the detected value P of the stage 15 is equal to or higher than the corrected corner fluid pressure value A, the solenoid 13a is turned on (step 0), the brake fluid at a predetermined pressure is confined in the containment chamber 42, and the brake fluid is transferred to the load sensing hub l1. When the break point is detected and the detected value P of the master cylinder hydraulic pressure detection means 15 is less than the corrected break point hydraulic pressure value A, the process returns to the initial stage without controlling the solenoid 13a.

On the other hand, in step (2), the solenoid 1 of the electric valve 13
If 3a is already ON, proceed to step [phase], and judge whether the detected value P of the master cylinder hydraulic pressure detection stage 15 is less than the corrected corner hydraulic pressure value A. If YES, Since there is no need to control the brake fluid pressure in the containment chamber 42,
In step (2), the solenoid 13a is turned OFF and the process returns to the initial stage. If NO, the containment chamber 42
Return to maintain the brake fluid pressure control state. [Effects of the Invention] As understood from the above explanation, according to the present invention, the solenoid valve is controlled by comparing the master cylinder hydraulic pressure, which is directly involved in braking force, and the corrected corner hydraulic pressure. Since this corrected corner hydraulic pressure is determined using the vehicle body deceleration and the master cylinder hydraulic pressure, the rear wheel wheel cylinder hydraulic pressure can be obtained with high accuracy depending on the friction coefficient of the lining or pad. , As a result, ideal control of four-wheel simultaneous locking can be provided. In addition, since the live load of the vehicle is determined by the live load calculation means from the amount of displacement between the sprung mass and unsprung mass of the vehicle in the non-braking operating state, the positive i1
As a result, an appropriate turning point hydraulic pressure can be provided, and ideal characteristics for four-wheel simultaneous locking can be provided.

[Brief explanation of drawings]

Fig. 1 is a layout diagram of structural elements of this invention, Fig. 2 is a layout diagram of structural elements showing an embodiment of this invention, Fig. 3 is a flowchart, and Fig. 4 is a sprung upper and lower part. Fig. 5 is a diagram showing the characteristics of the displacement amount in between and the basic corner point hydraulic pressure value, and Fig. 5 is a diagram showing the characteristics of the corner point hydraulic pressure correction amount and deceleration/master cylinder hydraulic pressure. 1: Master cylinder. 1b = Rear wheel side liquid chamber (liquid chamber),
2: Brake pedal. 3: Rear wheel, 4: Rear wheel cylinder, l1: Load sensing valve 13: Solenoid valve, 1
3a: Solenoid, 13c: Valve body, l5: Master cylinder hydraulic pressure detection means l6: Vehicle deceleration detection means, l8
Two basic corner point hydraulic pressure setting means, 19: corner point hydraulic pressure correction amount calculation means, 20: correction means, 21: comparison means. 22: Live load calculation means, 23: Storage device, 24: Displacement meter, 25: Spring, 26: Vehicle body. 30: Piston, 3l: Inflow ball 3
2: Outflow bow}, 33: First liquid chamber, 34: Second liquid chamber. 3
5: Valve, 38: Cylinder body, 40: Blowing spring, 41: Power piston, 42: Containment chamber, 43: Valve body housing space, SW: Brake switch (brake detection means).

Claims (1)

[Claims] (1) a master cylinder that generates pressure fluid during braking operation; an inflow port that communicates with the fluid chamber of the master cylinder;
a cylinder body having an outflow port that communicates with the rear wheel cylinder; a first liquid chamber that is slidably inserted into the internal space of the cylinder body and communicates with the inflow port; and a first liquid chamber that communicates with the outflow port. A piston that partitions the second liquid chamber and opens and closes a valve provided between the two liquid chambers by the liquid pressure acting on the difference in pressure receiving area, and a proportioning spring that opens the valve. A power piston that biases the piston, a containment chamber that is supplied with brake fluid that biases the power piston, and a fluid passageway that supplies brake fluid to the containment chamber, and communicates with the fluid passageway. or a control device for a load sensing valve comprising a solenoid valve that shuts off, a master cylinder hydraulic pressure detection means, a brake detection means for detecting a braking operating state or a non-braking operating state, sprung mass
A live load calculating means for calculating a live load from the amount of displacement between the unsprung parts; a basic corner hydraulic pressure setting means for calculating a basic corner hydraulic pressure value according to a setting value of the live load calculating means; A storage device for storing a hydraulic pressure value, a vehicle deceleration detecting means for detecting vehicle deceleration in a braking operation state, a detected value of the master cylinder hydraulic pressure detecting means, and a detected value of the vehicle deceleration detecting means. a corner point hydraulic pressure correction amount calculating means for calculating a corner point hydraulic pressure correction amount; and a comparison means that compares the corrected corner point hydraulic pressure value with a detected value of the master cylinder hydraulic pressure detection means and controls the solenoid valve to open or shut off based on the comparison result. A load sensing valve control device characterized by: