JPS58105863A - Controller for hydraulic pressure of rear wheel brake - Google Patents

Abstract

PURPOSE:To control a hydraulic pressure with high accuracy and without any scattering, by a method wherein rear wheel brake pressure is controlled by controlling a solenoid valve on the basis of a signal fed from a hydraulic pressure sensor. CONSTITUTION:A solenoid valve 22 is provided between a master cylinder 16 and a rear wheel brake 20, and is controlled by a controlling circuit 30 incorporating a microcomputer. Master cylinder pressure is detected by a hydraulic pressure sensor 24, and a pressure signal is inputted into the circuit 30 together with signals fed from load sensors 26, 28. The circuit 30 controls the valve 22 on the basis of the signal, thereby controlling the rear wheel brake pressure. Accordingly, since the rear wheel brake pressure is controlled by detecting the hydraulic pressure in the master cylinder, the hydraulic pressure of the rear wheel brake can be accurately controlled irrespectively of changes in temperature or with time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control device for rear wheel brakes, and more particularly to a hydraulic pressure control device that performs highly accurate hydraulic pressure control operations.

Since the load moves when the vehicle is braked, it is desirable to suppress the rear wheel braking force compared to the front wheel braking force in order to prevent the rear wheels from locking early. One of the measures for this purpose is to suppress the brake fluid pressure supplied to the rear brakes when the brake fluid pressure of the mask cylinder exceeds a predetermined value in the fluid passage between the mask cylinder and the rear brakes. Hydraulic pressure control devices have been provided in which hydraulic pressure control valves such as L valves and P valves are inserted. The hydraulic control valve of such a device is generally equipped with a valve piston that protrudes toward the low-pressure atmosphere from a valve chamber that receives braking fluid pressure against the preload of a spring or the like. The brake fluid pressure supplied to the rear wheel flakes is configured to be suppressed by the movement.

However, according to such conventional devices, there is a strong structure between the valve piston and the housing from which the valve piston is protruded, in order to make the gap between the valve chamber, which has an extremely large pressure difference, and the outside (atmospheric side) liquid-tight. A large sealing member is inserted, and the sealing member applies a large frictional resistance to the valve piston, and the frictional resistance is not uniform for each part and changes over time and temperature, so the valve piston The point at which the brake fluid pressure supplied to the rear wheel brake starts to be suppressed due to movement (node fluid pressure) varies not only between hydraulic control valves but also over time and temperature, resulting in low control accuracy. There were drawbacks. In particular, in two-line piping such as so-called X-shaped piping, between the mask cylinder and the right rear wheel brake, and between the mask cylinder and the left rear wheel brake,
If hydraulic control valves are inserted, the braking fluid pressures supplied to the left and right rear wheels will not match, resulting in uneven braking force on the left and right sides of the vehicle, which may impair vehicle stability. There was an inconvenience.

The present invention has been made against the background of the above circumstances,
The objective is to provide a highly accurate hydraulic pressure control device for rear wheel brakes in which control characteristics do not vary not only between hydraulic pressure control valves but also over time and temperature.

In order to achieve such an object, the rear wheel brake hydraulic pressure control device of the present invention reduces the front wheel braking force and rear wheel braking force of the vehicle by suppressing the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brakes. A rear wheel brake hydraulic pressure control device that adjusts a ratio of: (1) a hydraulic pressure sensor that detects a brake hydraulic pressure generated in the mask cylinder and outputs a hydraulic pressure signal representing the brake hydraulic pressure; (2) a control device that generates a suppression signal based on the hydraulic pressure signal and outputs the suppression signal; and a hydraulic pressure control valve that suppresses the brake fluid pressure supplied from the mask cylinder to the rear wheel brake.

In this way, the brake fluid pressure generated in the mask cylinder is detected by a fluid pressure sensor that does not require a valve piston, so the detection of the brake fluid pressure is almost independent of temperature changes and aging factors and is accurate. As a result, highly accurate hydraulic control operation with no variations can be obtained.

In another aspect of the present invention, the rear wheel brake fluid adjusts the ratio between the front wheel braking force and the rear wheel braking force of the vehicle by suppressing the brake fluid pressure supplied from the mask cylinder to the rear wheel brakes. The pressure control device includes: (1) a load sensor that detects the live load of the vehicle and outputs a load signal representing the live load; (2) detects the braking fluid pressure generated in the mask cylinder and controls the braking. (3) a hydraulic pressure sensor that outputs a hydraulic pressure signal representing hydraulic pressure; Based on a certain relationship, a corner brake hydraulic pressure corresponding to the live load represented by the load signal is determined, and as the brake fluid pressure represented by the hydraulic pressure signal increases, the corner brake hydraulic pressure increases. (4) is inserted in a fluid passage connecting the master cylinder and the rear wheel brake, and is supplied from the mask cylinder to the rear wheel brake in accordance with the suppression signal. and a hydraulic pressure control valve that suppresses the braking hydraulic pressure.

In this way, the brake fluid pressure generated in the mask cylinder is detected by a fluid pressure sensor that does not require a valve piston, so the brake fluid pressure can be detected accurately regardless of temperature changes or changes over time. As a result, highly accurate hydraulic control operation with no variations can be obtained. In addition, based on a predetermined constant relationship between the brake fluid pressure at which suppression of the brake fluid pressure supplied to the rear wheel brakes should start and the vehicle's vehicle load, a corner point corresponding to the actual load is determined. The brake fluid pressure is determined, and when the brake fluid pressure generated in the mask cylinder exceeds the corner brake fluid pressure, the fluid pressure control valve is operated, so that the desired rear wheel braking force corresponding to the live load can be obtained. In addition, the hydraulic pressure control valve can be easily installed without being associated with the suspension system of the vehicle, and a single type of hydraulic pressure control valve can be used in many types of vehicles with different suspension structures.

Here, the corner brake hydraulic pressure refers to the brake hydraulic pressure of the mask cylinder in a state where suppression of the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brake starts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below based on the drawings.

In FIG. 1, the mask cylinder 10 is equipped with a first hydraulic pressure chamber 14 and a second hydraulic pressure chamber 16 in which equal braking hydraulic pressure is generated as the brake pedal 12 is operated. 14 is connected to a wheel cylinder 18 of a front wheel brake, and the second hydraulic pressure chamber 16 is connected to a wheel cylinder 20 of a rear wheel brake via an electromagnetic on-off valve 22 which is a hydraulic pressure control valve. The vehicle includes a hydraulic pressure sensor 24 connected to the second hydraulic pressure chamber 16 that detects the brake hydraulic pressure generated in the mask cylinder 10 and outputs a hydraulic pressure signal 8A representing the brake hydraulic pressure, and a hydraulic sensor 24 that detects the brake hydraulic pressure generated in the mask cylinder 10 and outputs a hydraulic pressure signal 8A representing the brake hydraulic pressure. A left load sensor 26 and a right load sensor 28 are provided for detecting the loads applied to the left and right rear wheels, respectively, and outputting a left load signal LW and a right load signal RW representing the loads.

The hydraulic pressure signal 8A, left load signal LW and right load signal RW are supplied to a control circuit 30 which is a control device, and a suppression signal SL is outputted from the control circuit 30 to the electromagnetic on-off valve 22. There is.

As shown in FIG. 2, the control circuit 30 includes low-pass filters 82, 84 . Set value adjustment circuit 86° comparison circuit 88
and a driver circuit 40. The low-pass filter 82 includes resistors 42, 44, 46, 48, . A well-known low-pass active filter for noise removal consisting of a capacitor 50, 52 and an operational amplifier 56, whose input signals are a left weight signal LW and a right weight signal RW.
The low frequency component of the approximately average value of is amplified at a predetermined constant amplification factor, and a corner signal 8D representing the corner liquid pressure is outputted to the comparison circuit 88 via the set value adjustment circuit 86. The set value adjustment circuit 86 is a series circuit of a variable resistor 58 and a fixed resistor 60 inserted between the power supply and the ground terminal, and by operating the variable resistor 58, the corner signal 8D is adjusted. This is to fine-tune the Similar to the low-pass filter 32, the low-pass filter 34 includes a resistor 62.6B.

64, a low-pass active filter consisting of capacitors 66, 68, and an operational amplifier 70, which supplies a hydraulic pressure signal SA that amplifies the low frequency component of the input signal from the hydraulic pressure sensor 24 to the comparison circuit i@as. The comparison circuit 88 compares the input corner signal 8D and the hydraulic pressure signal SA, and calculates the hydraulic pressure signal SA.
When exceeds the corner signal 8D, an output signal (H level) is supplied to the driver circuit 40. The driver circuit 40 is composed of a bias resistor 69 and a transistor 1, and when a signal is input from the comparator circuit 88, a transistor 71 is activated to send a suppression signal 8L to the electromagnetic on-off valve 22, that is, a drive current. supply.

Here, the point at which suppression of the brake fluid pressure supplied to the rear wheel brakes starts, that is, the corner brake fluid pressure indicated by the corner signal SD, is the ratio of the front wheel braking force to the rear wheel braking force. It is determined according to a certain functional relationship shown in Figure 3, which approximates the ideal ratio corresponding to changes in live load and obtains as much rear wheel braking force as possible while preventing rear wheel lock. Good. In the low-pass filter 32, an amplification factor is determined based on the functional relationship (slope), and is used to obtain an ideal braking force ratio corresponding to the load represented by the input load signals LW and l'tW. A corner signal SD representing the corner braking hydraulic pressure is output. In other words, when the live load is small, rear wheel lock is likely to occur when the rear wheel load is small and the brake fluid pressure is relatively low (at the beginning of braking), so it is necessary to reduce the corner fluid pressure, and vice versa. If the load is large, rear wheel lock will not occur until the rear wheel load is large and the braking fluid pressure becomes relatively large (until the braking effect becomes large), so rear wheel braking is performed by increasing the corner fluid pressure. It is necessary to increase the power as much as possible.

The electromagnetic on-off valve 22 closes the fluid passage from the second hydraulic pressure chamber 16 of the mask cylinder 10 to the wheel cylinder 20 in accordance with the suppression signal SL, so that the braking hydraulic pressure supplied to the wheel cylinder 20 is suppressed. That is, the fourth
As shown in the figure, a first boat 72 communicating with the second hydraulic pressure chamber 16 and a second boat 74 communicating with the wheel cylinder 20 are formed in a housing 76, and a valve cover 78 is screwed into the housing 76. By fitting together, a valve chamber 8° connecting the first port 72 and the second boat 74 is formed. A poppet valve 86 biased toward the valve seat 84 by a spring 82 is accommodated in the valve chamber 8o, and when the poppet valve 86 is seated on the valve seat 84, the second boat 74 and the valve chamber 80 are separated. communication is now cut off.

Inside the housing 76, a cylindrical solenoid 90 is fixed by a lower cover 88 screwed to the bottom of the housing 76, and a resolenoid 90 is fixed to the lower cover 88 in a liquid-tight manner.
A sleeve 92 made of a non-magnetic material is inserted into the poppet valve 86, and a cylindrical core 94 is fitted into the sleeve 92 so as to be movable in the axial direction and abuts the lower protrusion of the poppet valve 86. A spring 96 is inserted between the core 94 and the lower lid 88 to move the poppet valve 86 and the core 94 against the biasing force of the spring IJ ring 82. Therefore, in the electromagnetic on-off valve 22, when the solenoid 90 is not energized, the poppet valve 86 is
4, the first boat 72 and the second boat 74 are brought into communication, and when the solenoid 90 is energized via the lead wire 92, the core 94 is attracted against the biasing force of the spring 96, and the poppet valve 86 is seated on the valve seat 84, and the first port 72 and the second boat 74 are cut off. Note that when the pressure in the second boat 74 becomes higher than the pressure in the valve chamber 80, the poppet valve 86 is moved away from its seat against the biasing force of the spring 82, so the electromagnetic on-off valve 22 also functions as a check valve. We are prepared. In addition, a through hole 98 is formed in the core 94 so as to pass through it in the axial direction in order to equalize the pressure on both end faces of the core 94, so that the operation of the core 94 is not inhibited by the brake fluid pressure.

The operation of this embodiment will be explained below.

Along with the operation of the flake header 12, the mask cylinder 1
When the brake fluid pressure generated at zero is supplied to the wheel cylinders 18,20, the vehicle begins to decelerate slightly due to the braking forces generated at the front and rear wheels of the vehicle. At the start of such braking, the mask cylinder 1 represented by the hydraulic pressure signal SA
The left and right load signals LW compared to the braking fluid pressure of o is extremely small.

Since the respective loads represented by KW are large and the corner signal 8D is still larger than the hydraulic pressure signal SA, the suppression signal SL is not supplied to the electromagnetic on-off valve 22, and the electromagnetic on-off valve 22
communicates between the second hydraulic chamber 16 and the wheel cylinder 20. FIG. 4 shows this state.

When the braking hydraulic pressure of the mask cylinder 10 is increased to produce a braking effect on the vehicle, the hydraulic pressure signal SA increases, but the load represented by the left and right load signals LW and RW decreases due to the load shift, and a turning point is reached. Signal SD becomes smaller. When the hydraulic pressure signal 8A exceeds the corner signal 14-8D, an output signal is output from the comparison circuit 38, and a suppression signal SL is output from the driver circuit 40 to the electromagnetic on-off valve 2.
2. Therefore, since the electromagnetic on-off valve 22 is closed, the brake fluid pressure supplied to the wheel cylinders 20 from the second hydraulic pressure chamber 16 is thereafter cut off, and the rear wheel braking force increases regardless of the increase in the front wheel braking force. Rise is limited.

In such an operation, if the load on the vehicle changes significantly, for example, the left and right load signals T, W, and I (W increase accordingly, so the corner signal SD increases. Therefore, the braking of the mask cylinder 10 When the hydraulic pressure is further increased and the braking effect of the vehicle becomes even greater, the hydraulic pressure signal SA is activated.
exceeds the corner signal SD, and suppression of the brake hydraulic pressure supplied from the second hydraulic pressure chamber 16 to the wheel cylinder 20 starts. As a result, in the graph showing the relationship between the front wheel braking force and the rear wheel braking force in FIG. 5, the characteristics shown by the two-dot chain line, which approximate the ideal curve shown by the solid line at each load, are obtained. The braking force of the brake and the magnitude of the braking fluid pressure supplied to the wheel cylinder are approximately proportional to each other.

In this way, according to this embodiment, the ratio of the front wheel braking force to the rear wheel braking force is the ideal ratio (shown by the ideal curve above) that provides the maximum rear wheel braking force within the range where the rear wheels do not lock. As shown in FIG. The position can be changed to a suitable position according to the load, and desired rear wheel braking force can be obtained.

Since the brake fluid pressure of the mask cylinder 1o is detected by the fluid pressure sensor 24, which does not require a valve piston, the brake fluid pressure can be detected accurately regardless of temperature changes or changes over time, and variations in the brake fluid pressure can be achieved. This results in highly accurate hydraulic control operation. Generally, the liquid tuna sensor 24 is configured to electrically detect the amount of movement of a diaphragm that is displaced in accordance with the braking fluid pressure, and has high detection accuracy and extremely small temperature changes and changes over time.

Furthermore, since the electromagnetic on-off valve 22 is configured to open when power is not applied, the operation of the rear wheel brakes is ensured even in the event of a failure of the control circuit 30 or the solenoid 90, which has the advantage of maintaining a high level of vehicle safety. be.

Furthermore, the load sensors 26, 28 and the electromagnetic on-off valve 22, which is a hydraulic pressure control valve, do not require a mechanical relationship with each other and can be mounted at their own locations. Therefore, unlike conventional live load detection systems, it does not need to be installed in conjunction with a suspension system that detects the load. There is an advantage that a single type of hydraulic control valve can be used.

Next, another embodiment of the present invention will be described. In the following embodiments, the same parts as those in the above-mentioned embodiments are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the embodiments described above, the control circuit 30 is configured with an analog circuit, but it can also be configured with a digital circuit as follows.

In Fig. 6, control circuit 1 'O□0 is digital circuit 1
The hydraulic pressure signal SA output from the hydraulic pressure sensor 24 is supplied to the A/D converter 102 via the low-pass filter 34. Similarly, the left load signals ■ and W output from the left load sensor 26 and the right load sensor 28
The right load signal RW and the right load signal RW are averaged by passing through a low-pass filter 32, and are supplied to the A/D converter 102 as a load signal sw representing the rear wheel load.

The A/D converter 102 converts an analog signal into a digital code signal representing the magnitude thereof, converts the input load signal SW and hydraulic pressure signal SA into digital code signals, and connects the data bus line. Intervention 1. CPU
10'4. RAMI O6゜ROMI O8, T10 Baud) Supplied to 110.

(J, PUi04 is an arithmetic control unit and ROM I
RAM106 according to the program stored in advance in Q8.
In addition to practical calculation control while utilizing the memory function of
It outputs a signal to the outside or inputs an external signal through the T10 baud) 110.

The brake pedal 18 is located at the I'10 to □ ports
- A brake switch l12 which is activated in response to the operation of the brake pedal 12 is connected, and a pedal operation signal SP indicating that the brake pedal 12 has been operated is supplied.

The suppression signal SL is supplied from the I10 boat 110 to the electromagnetic on-off valve 22 via the driver 114.

The control circuit 100 configured as described above has the ROM1 stored in advance.
It operates according to the program stored in 08 as shown in the flowchart of FIG.

That is, first, in step S1, the operating state of the brake switch 112 is determined, and if the pedal operation signal SP has not yet been generated, step S1 is repeated. When the brake pedal 12 is operated, a pedal operation signal SP is generated.
is supplied to the CPU I04 via the I10 boat 110, steps S2 to S5 are executed. That is,
In step S2, the load signal SW is applied to the live load W.
is read, and in step S3, the corner point corresponding to the actual live load W represented by the load signal SW is determined from the relationship (corresponding data) between the live load and the corner point braking hydraulic pressure shown in FIG. 3, which is stored in advance in the ROM 10B. The brake fluid pressure X is determined, and the brake fluid pressure Y in step S4 is the corner brake fluid pressure X.
A comparative judgment is made as to whether or not it is greater than.

At the initial stage of braking, the brake fluid pressure Y of the mask cylinder 10 is still small compared to the corner brake fluid pressure X, so step S
6 and S7 are executed, the output of the suppression signal SL is blocked and the electromagnetic on-off valve 22 is held in the open state, and
The operating state of brake switch 112 is determined. When the operation of the brake pedal 12 is released and the pedal operation signal SP disappears, the process is executed again from step S1 via step S8, which opens the electromagnetic on-off valve 22, but the operation of the brake pedal 12 is continued and the pedal operation signal SP If SP continues to occur, the process starts from step S4.

While the above operations are repeated at high speed, when the braking effect of the vehicle becomes large and the brake fluid pressure Y of the vehicle exceeds the corner brake fluid pressure X, steps S9 and S7 are executed. That is, in step S9, the I10 boat IIO
A suppression signal SL is supplied from the driver 114 to the electromagnetic on-off valve 22, and the braking hydraulic pressure supplied from the second hydraulic pressure chamber 16 to the wheel cylinder 20 is suppressed by the closing operation of the electromagnetic on-off valve 22. , then step 87
In the following, operations similar to those described above are performed.

In the above operation, the corner braking hydraulic pressure Since it is determined based on the relationship between the corner braking hydraulic pressure and the live load, the relationship between the front wheel braking force and the rear wheel braking force shown by the two-dot chain line in FIG. 5 can also be obtained in this example. It is.

As described above, according to the present embodiment, in addition to obtaining the same effects as in the above-described embodiment, the load W represented by the load signal 8W remains at the brake pedal 12 where the vehicle is still stable.
Since the load signal SW is read at the start of the operation, variations in the load signal SW due to unevenness of the road surface, etc. can be easily eliminated, and more stable hydraulic control operation can be obtained. The relationship between the live load and the corner brake hydraulic pressure used in this embodiment differs in that the live load W is a value detected when the vehicle is stable.

Furthermore, according to the present embodiment, since the control circuit 100 is configured with a digital circuit, it can withstand noise that often occurs in vehicles and temperature drift caused by harsh temperature environments.
It has the advantage of extremely stable operation compared to analog circuits.

Furthermore, this embodiment has the advantage that even if the relationship shown in FIG. 8 is non-linear, it is not necessary to change the equivalent circuit configuration.

The hydraulic pressure control valve of the above-mentioned embodiment is configured to block the brake fluid pressure supplied to the rear wheel brake only by the electromagnetic on-off valve 22, but as follows, the electromagnetic on-off valve 22 is The brake fluid pressure supplied to the brake is transferred to the mask cylinder 10.
It can also be configured to be connected to a device that reduces the brake fluid pressure at a constant rate.

22- In FIG. 8, the pressure reducing device 116 is the first bow)
118 and a second boat 120 are connected in parallel to the electromagnetic on-off valve 22 while being connected to the second hydraulic chamber 16 of the mask cylinder IO and the wheel cylinder 20 of the rear wheel brake. The valve cover 124 is screwed into the housing 122 to form a large diameter cylinder bore 126 in the form of a circular hole with an eave formed in the housing 122 and a small diameter cylinder bore in the form of a circular hole with an eave formed in the valve cover 124. A large-diameter piston 132 and a small-diameter piston 134 are slidably fitted into the large-diameter cylinder bore 126 and the small-diameter cylinder bore 128, respectively. Those pistons 132,
184 is a spring receiver 136 which is brought into contact with each other and is attached to the cavity 130 side of the large diameter piston 182;
A compression coil spring 138 is inserted between the valve cover 124 and the large diameter piston 182, and the large diameter piston 182 is always urged toward the bottom of the large diameter cylinder bore 126. Note that the first boat 118 and the second boat 120 are communicated with a small diameter cylinder bore 128 and a large diameter cylinder bore 126, respectively.

Therefore, when the suppression signal SL is not yet supplied to the electromagnetic on-off valve 22, the braking fluid pressure in the second hydraulic pressure chamber 16 is directly supplied to the wheel cylinder 20 through the electromagnetic on-off valve 22 in the open state, and As the braking fluid pressure increases, the large diameter piston 182 is moved toward the cavity 130 against the biasing force of the compression coil spring 138.

Next, when the suppression signal SL is supplied and the electromagnetic on-off valve 22 is closed, the pressure applied to the small diameter piston 184 according to the braking fluid pressure supplied through the first boat 118 and the biasing force of the compression coil spring 138 The large-diameter piston 132 is moved, and as the large-diameter piston 132 moves, the braking fluid pressure generated within the large-diameter cylinder bore 126 is applied to the second boat 120.
It is supplied to the wheel cylinder 20 through. At this time, since the diameter of the small-diameter piston 134 is set smaller than the diameter of the large-diameter piston 132, the small-diameter cylinder bore 12
Compared to the increase in braking fluid pressure in 8, the large diameter cylinder bore 1
The brake fluid pressure in 26 increases at a reduced value at a constant rate. The large diameter piston 132 is connected to the large diameter cylinder bore 12.
6, the braking fluid pressure supplied to the wheel cylinder 20 is prevented from increasing. The point in time until the braking fluid pressure is stopped from increasing is the amount by which the large diameter piston 132 has moved against the biasing force of the compression coil spring 188, depending on the magnitude of the braking fluid pressure supplied through the electromagnetic on-off valve 22. determined by

As a result, as shown by the two-dot chain line in FIG.
This results in a ratio characteristic between the front wheel braking force and the rear wheel braking force that more closely approximates the ideal curve (solid line) that corresponds to changes in the live load.

In FIG. 10, the proportional control valve 140 has a first boat 144 and a second boat 146 provided on its housing 142 and a third port 150 provided on its valve cover 148.
The first boat 144 includes a mask cylinder 10
is connected to the second hydraulic pressure chamber 16 of the first boat 1.
An electromagnetic on-off valve 22 is connected between the 44 and the second bow 146, and the 25-third port 150 is connected to the wheel cylinder 2 of the rear wheel brake.
Connected to 0. Inside the housing 142 is a valve cover 14.
8 are screwed together, a stepped hole-shaped valve chamber is formed, and a cup-shaped elastic valve seat 15 is provided in the stepped portion.
2 is disposed, and a valve piston 154 passing through the elastic valve seat 152 is disposed so as to be movable in the axial direction.

A large-diameter valve element 156 is provided at the tip of the valve piston 154 and has a pressure-receiving surface and can be seated on the elastic valve seat 152.The small-diameter side of the valve chamber with the elastic valve seat 152 as a boundary is a third valve element 156. The large diameter side of the port 150 is connected to the first boat 144 . On the other hand, a lower cover 158 in which a cylinder bore 157 is formed is screwed into the lower part of the housing 142, so that a spring chamber 158 separating the valve chamber and the partition wall 160 is formed.
62 is formed. In the spring chamber 162, a coil spring 168 is inserted between a piston 164 that is slidably fitted into the cylinder bore 157 and a spring receiver 166 that abuts the valve piston 154 that protrudes through the partition wall 160. 26- The valve piston 154 has its valve element 156 on the elastic valve seat 1.
It is biased in the direction away from 52. A second boat 146 is communicated within the cylinder bore 157.

Therefore, when the suppression signal SL is not yet supplied to the electromagnetic on-off valve 22, the braking hydraulic pressure in the second hydraulic pressure chamber 16 is supplied to the first boat 144 and the second boat 146. For this reason, the piston 164 is moved to the coil spring 168 by the braking fluid pressure supplied through the second boat 146.
Since the coil spring 168 is moved against the biasing force of the valve piston 154, the biasing force applied to the valve piston 154 from the coil spring 168 increases, and the valve piston 154 maintains its valve element 156 separated from the elastic valve seat 152. be done. As a result, the first boat 144 and the third boat 150 are maintained in communication via the valve chamber, so that the braking hydraulic pressure in the second hydraulic pressure chamber 16 is directly supplied to the wheel cylinder 20. be.

Next, when the suppression signal SL is supplied and the electromagnetic on-off valve 22 is closed, the increase in the braking fluid pressure supplied to the second boat 146 is prevented and the movement of the piston 164 is stopped +hL. A biasing force is applied from the coil spring 168 to the valve piston 154. On the other hand, the first boat 1
44 is increased, the valve piston 154 is moved toward the anti-slip chamber 162 by the biasing force of the coil spring 168, and the valve element 156 is seated on the elastic valve seat 152. For this reason, the elastic valve seat 152
The valve piston 154 moves slightly so that the biasing force based on the pressure receiving area difference of the valve piston 154 and the biasing force of the coil spring 168 are balanced, and the braking fluid in the third port 150 is pressure is the first
The boat 144 is raised at a lower rate of increase than the rate of increase of the brake fluid pressure of the boat 144.

As a result, as shown by the two-dot chain line in Fig. 11, a ratio characteristic between the front wheel braking force and the rear wheel braking force is obtained that more closely approximates the ideal curve (solid line) according to the change in live load. .

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other embodiments.

For example, the brake fluid pressure generated in the mask cylinder 10 is
The transmission may be configured to be transmitted to the wheel cylinders 18 and 20 of each wheel through a so-called X-shaped pipe consisting of a pipe connecting the right front wheel and the left rear wheel and a pipe connecting the left front wheel and the right rear wheel. Of course. However, in this case,
Although a hydraulic pressure control valve is inserted in each piping system, the turning point hydraulic pressure of the left and right hydraulic pressure control valves can be made to match, which has the advantage that the dispersion in the braking force of the left and right rear wheels is almost eliminated. be.

The electromagnetic on-off valve 22 is connected to the wheel cylinder 2 of the rear wheel brake.
Anything that can suppress the braking fluid pressure supplied to 0 is sufficient.
Of course, there is no problem even if the valve does not have a check valve function but only has an opening/closing function.

In the embodiment described above, the left load sensor 26 and the right load sensor 28 are provided to detect the live load of the vehicle, but the live load may be detected by a single load sensor. . However, if the loaded load is uneven, by providing load sensors 26, 28 on both the left and right sides of the vehicle, the loaded load can be accurately detected, and locking of the rear wheels can be more reliably prevented.

The aforementioned control circuit 100 may be partially or entirely constituted by a so-called microcomputer, and the microcomputer may also be used for other purposes at the same time.

The load sensors 26 and 28 mentioned above may be configured to be attached to the loading platform and directly detect the vehicle's loaded load, but they may also be configured to directly detect the vehicle's carrying load, but they may also be configured to directly detect the vehicle's loading load by using deformation of the vehicle's suspension system. It may be configured to indirectly detect the live load by detecting movement or by detecting the air pressure of a pneumatic suspension system, a vehicle height adjustment device, or the like.

Further, in steps S1 and S2 of the embodiment shown in FIG. 7, the loading load W may be read in advance using another timing signal generated in the steady state of the vehicle.

Furthermore, in the embodiments described above, the load sensors 26, 28
is provided so that the 30-point braking hydraulic pressure is changed according to the vehicle's carrying load. The hydraulic pressure may be determined, and based on the braking hydraulic pressure generated in the mask cylinder 10,
The target braking fluid pressure to be supplied to the wheel cylinder 20 of the rear wheel brake from the vehicle load or the front wheel load and the rear wheel load is sequentially determined as the brake fluid pressure of the mask cylinder 10 increases to -, and the target braking pressure is determined. The brake fluid pressure supplied to the wheel cylinders 20 may be controlled so as to follow the fluid pressure. In addition, in the case of [(j) cars in which the live load does not change that much, the corner brake fluid pressure should be a predetermined constant value - (t).In such a case, the load The sensors 26 and 28 are no longer required, and the control circuits 30 and 100 are activated to generate a suppression signal when the hydraulic pressure signal 8A representing the braking hydraulic pressure at the mask cylinder level reaches a predetermined constant corner signal -(2 times). All you need is a control device that outputs .

The pressure sensor and control device in that case are also configured as follows. For example, a diaphragm corresponding to a pressure sensor is provided that is displaced against the biasing force of a spring according to the brake fluid pressure of the mask cylinder river O, and the diaphragm reaches a position corresponding to a predetermined constant brake fluid pressure. It may be configured by providing a switch that is activated when this happens.

At this time, the movement of the diaphragm is the hydraulic pressure signal SA, and the spring and switch are the control device that outputs the suppression signal. In short, the control device may be one that generates and outputs the suppression signal SL based on the hydraulic pressure signal.

The above-described embodiments are merely examples of the present invention, and the present invention may be modified in various ways without departing from its spirit. The hydraulic pressure control valve for the rear wheel brake of the invention detects the brake fluid generated in the mask cylinder by a hydraulic sensor that does not require a valve piston, so it is not affected by changes in humidity or changes over time due to the detection of brake fluid pressure. Regardless of the situation, the hydraulic pressure control operation is accurate and highly accurate with no variations. Therefore, in the case of two-system piping that requires hydraulic pressure control for each left and right rear wheel brake, compared to conventional hydraulic pressure control valves such as ■7 valves and P valves, it is possible to Braking power can be obtained.

Further, in another aspect of the present invention, in addition to the effect described in I- below, based on a predetermined constant relationship between 1J point brake fluid IF: and the vehicle's live load, the actual live load is χ
・The corresponding corner brake fluid pressure is determined, and the brake fluid pressure generated in the mask cylinder increases the corner brake fluid pressure by 1-
, since the hydraulic pressure control valve is activated when the vehicle rotates, the desired rear wheel braking force corresponding to the load can be obtained, and
Hydraulic control: The control valve can be easily installed without being associated with the suspension system of the vehicle, and a single type of hydraulic control valve can be used for many types of embossing with different suspension patterns.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a wiring diagram illustrating the control circuit of the embodiment shown in FIG. FIG. 3 is a graph showing the relationship between the product calculated in advance and the brake fluid pressure at one point, which is used in the control circuit of FIG. 1. Figure 4 is the first
It is a sectional view showing the composition of the electromagnetic on-off valve in the example of the figure. FIG. 5 is a graph illustrating the operation of the embodiment shown in FIG. FIG. 61 is a block diagram showing a control device 2 in another embodiment of the present invention. FIG. 7 is a flowchart illustrating the operation of the control device of FIG. 6. FIG. 8 and FIG. 1O are diagrams each illustrating the structure of a hydraulic pressure control valve in another embodiment of the present invention. Figures 9 and 11
The figures are graphs illustrating the operation of the embodiments of FIGS. 8 and 10, respectively. 10: Master cylinder 24: Hydraulic pressure sensor 34 - Fig. 3 Live load claw Fig. 4 Fig. 5 Front wheel braking force Fig. 6
Paraiba A102 ---
SL/ Fig. 7 scolding 8), Fig. 9- Fig. 11 #1 @ snout 1 initial force element 10

Claims (2)

[Claims] (1) A rear wheel brake hydraulic pressure control device that adjusts the ratio of front wheel braking force and rear wheel braking force of a vehicle by suppressing the brake fluid pressure supplied to the rear wheel brakes from a mask cylinder, comprising: a hydraulic pressure sensor that detects braking hydraulic pressure generated in the mask cylinder and outputs a hydraulic pressure signal representing the braking hydraulic pressure; and a control device that generates a suppression signal based on the hydraulic pressure signal and outputs the suppression signal. and a hydraulic pressure control valve that is inserted in a fluid passage connecting the mask cylinder and the rear wheel brake, and that suppresses the braking hydraulic pressure supplied from the mask cylinder to the rear wheel brake in accordance with the suppression signal. A rear wheel brake hydraulic pressure control device featuring: (2) A rear wheel brake hydraulic pressure control device that adjusts a ratio between a front wheel braking force and a rear wheel braking force of a vehicle by suppressing the brake fluid pressure supplied to the rear wheel brakes from a mask cylinder, the vehicle a load sensor that detects the live load of the mask cylinder and outputs a load signal representing the live load, and a hydraulic pressure sensor that detects the braking fluid pressure generated in the mask cylinder and outputs a fluid pressure signal representing the braking fluid pressure. and, based on a predetermined constant relationship between the turning point brake fluid pressure at which suppression of the brake fluid pressure supplied to the rear wheel brake should start and the vehicle load, the load represented by the load signal is adjusted. a control device that determines a corresponding corner braking fluid pressure and outputs a suppression signal when the braking fluid pressure represented by the fluid pressure signal exceeds the corner braking fluid pressure as the fluid pressure signal increases; a hydraulic pressure control valve that is inserted into a fluid passage connecting the rear wheel brake and that suppresses braking hydraulic pressure supplied from the master cylinder to the rear wheel brake in accordance with the suppression signal. Brake hydraulic control device.