JPS58112863A - Hydrostatic control device for rear wheel brake - Google Patents

Abstract

PURPOSE:To obtain the optimum braking force for rear wheels in accordance with the mounted load by controlling a hydrostatic control valve by means of a control device to make computation according to a fixed functional relation indicating the ideal distribution of front and rear wheel braking forces on the basis of a mounted load signal and a deceleration signal. CONSTITUTION:The operation of a hydrostatic control valve 22 in a rear wheel braking circuit is controlled by a control circuit 30. That is, a deceleration signal SG from a deceleration sensor 24 and front and rear load signals FW and RW from front and rear wheel load sensors 26 and 28 are respectively supplied to an A/D converter 34 in the control circuit 30 via low-pass filters 32, 36, and 38. On the basis of the signal converted into a digital code by the converter 34, a CPU40 makes computation according to a program previously memorized in an ROM44 using the memorizing function of an RAM42, and outputs a signal via an I/O port 46 and a driver 50. By the signal thereof, the hydrostatic control valve 22 is controlled. The above-said program is prepared on the basis of a fixed functional formula indicating the ideal distribution of front and rear wheel braking forces using variables of front and rear wheel loads.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control device for rear wheel brakes in a vehicle, and more particularly to a hydraulic pressure control device that changes its operating point in accordance with the load and operates with high precision. .

When braking a vehicle, the load moves, so it is desirable to combine the rear wheel braking force with respect 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 insert a pulp (inertia valve) into the fluid oil between the mask cylinder and the rear wheel brake. The housed ball valve is seated on the valve seat against the inclined surface,
A hydraulic pressure control device is provided that suppresses the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brake after that.

However, such conventional hydraulic pressure control devices uniformly suppress the braking force of the rear wheel brakes when the deceleration of the vehicle exceeds a certain level. There was an inconvenience that rear wheel braking force could not be obtained.

In other words, in order to obtain an ideal distribution of front wheel braking force and rear wheel braking force that can obtain large braking force while preventing rear wheel locking, as the load of the vehicle increases, the supply to the rear wheel brakes increases. It is necessary to increase the rear wheel braking force by increasing the deceleration at the point where the brake fluid pressure starts to be suppressed.
The operating deceleration of the G valve in a conventional hydraulic pressure control device is constant, and the brake fluid pressure value is sufficient to suppress the supply of brake fluid pressure to the rear wheel brakes in response to changes in the vehicle's payload. This results in a lack of rear wheel braking force.

In addition, in G-pulp in conventional hydraulic control devices, the ball valve that operates by inertia is housed in the valve chamber together with the brake fluid, so the operation of the ball valve may be affected by changes in the viscosity of the brake fluid due to temperature changes or changes over time. The disadvantage was that the operating point of hydraulic pressure control varied greatly.

The present invention has been made against the background of the above circumstances,
The purpose is to provide a rear wheel brake hydraulic pressure control device that can obtain a desired rear wheel braking force according to the load and has high operational accuracy.

In order to achieve such an object, the rear wheel brake hydraulic pressure control device of the present invention suppresses the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brakes, thereby increasing the front braking force and the rear wheel braking force of the vehicle. This is a rear wheel brake hydraulic pressure control device that adjusts the ratio between the front wheels of the vehicle and the rear wheel brakes, the device comprising: (1) a front wheel load sensor that detects a load applied to the front wheels of a vehicle and outputs a front load signal representing the load; (2) a rear wheel load sensor that detects a load applied to the rear wheels of a vehicle and outputs a rear load signal representing the load; and (3) detects deceleration of the vehicle and outputs a deceleration signal representing the deceleration. a deceleration sensor; (4) a predetermined fixed functional relationship representing an ideal distribution of front wheel braking force and rear wheel braking force with front wheel load and rear wheel load as variables; and the front load signal and rear load signal. When calculating the value of the standard rear wheel braking force when the front wheel braking force of the vehicle is a predetermined blind value based on A corner deceleration corresponding to the calculated reference rear wheel braking force is determined based on the determined constant relationship, and as the deceleration of the vehicle represented by the deceleration signal increases, the corner deceleration increases. (5) a control device that is inserted in a fluid passage connecting the mask cylinder and the rear wheel brake and supplies the rear wheel brake from the mask cylinder in accordance with the suppression signal; It is characterized in that it includes a hydraulic pressure control valve that suppresses the clam liquid pressure.

In this way, a predetermined constant functional relationship representing an ideal distribution of front wheel braking force and rear wheel braking force with front wheel load and rear wheel load as variables, and the front load signal and rear load signal can be set. Based on this, the value of the reference rear wheel braking force when the front wheel braking force of the vehicle is a predetermined constant value is calculated, and the value of the reference rear wheel braking force and the corner deceleration is determined to be a predetermined constant value. The corner deceleration corresponding to the calculated reference rear wheel braking force is determined based on the relationship, and the hydraulic control valve is operated when the deceleration of the vehicle exceeds the corner deceleration. Regardless of the loading position, a desired rear wheel braking force can be obtained in accordance with the loaded load. Since the deceleration of the vehicle is detected by a deceleration sensor that is not related to the fluid passage that transmits brake fluid pressure, deceleration can be detected accurately regardless of changes in the viscosity of the brake fluid, resulting in consistent and accurate detection. The result is a hydraulic control operation.

Further, in another aspect of the present invention, a rear wheel brake hydraulic pressure control device controls the ratio of the front wheel braking force and the rear wheel braking force of the vehicle by suppressing the brake hydraulic pressure supplied to the rear wheel brakes from the mask cylinder. A rear wheel brake hydraulic pressure control device that adjusts (1) a front wheel load sensor that detects a load applied to the front wheels of a vehicle and outputs a front load signal representing the load; (2) a rear wheel of the vehicle; (3) a rear wheel load sensor that detects the load applied to the vehicle and outputs a rear load signal representing the load; and (3) an deceleration sensor that detects the deceleration of the vehicle and outputs a deceleration signal representing the deceleration. (4) Based on a predetermined fixed functional relationship representing the ideal distribution of front wheel braking force and rear wheel braking force with front wheel load and rear wheel load as variables, and the front load signal and rear load signal. Calculating a reference rate of change in rear wheel braking force when the front wheel braking force of the vehicle is a predetermined constant value, and
Based on a predetermined constant relationship between the reference rate of change of the rear wheel braking force and the corner deceleration, the calculated reference rate of change (the corresponding corner deceleration is determined), and the deceleration signal is (5) a control device that outputs a suppression signal when the deceleration of the vehicle exceeds the turning point deceleration as the deceleration of the vehicle increases; The present invention is characterized in that it includes a hydraulic pressure control valve that suppresses the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brake in accordance with the suppression signal.

In this way, a predetermined constant functional relationship representing an ideal distribution of front wheel braking force and rear wheel braking force with front wheel load and rear wheel load as variables, and the front load signal and rear load signal can be set. Based on this, the reference rate of change in the rear wheel braking force when the front wheel braking force of the vehicle is a predetermined constant value is calculated, and the reference rate of change in the rear wheel braking force and the corner deceleration are calculated in advance. A corner deceleration corresponding to the calculated reference rate of change is determined based on a predetermined constant relationship, and the hydraulic control valve is actuated when the deceleration of the vehicle exceeds the corner deceleration. Therefore, the desired rear wheel braking force can be obtained in accordance with the loaded load regardless of the loading position. Since the deceleration of the vehicle is detected by a deceleration sensor that is not related to the fluid passage that transmits brake fluid pressure, deceleration can be detected accurately regardless of changes in the viscosity of the brake fluid, resulting in consistent and accurate detection. The result is a hydraulic control operation.

Here, the corner deceleration indicates the deceleration value at which the brake fluid pressure supplied from the mask cylinder to the rear wheel brakes starts to be suppressed, and is the difference between the front wheel braking force and the rear wheel braking force of the vehicle. In a graph representing the relationship, in other words, a graph representing the relationship between the brake fluid pressure generated in the mask cylinder (brake fluid pressure supplied to the front wheel brakes) and the brake fluid pressure supplied to the rear wheel brakes, This corresponds to the point in time when the characteristic curve forms an inflection point.

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 has a first brake cylinder in which equal braking fluid pressure is generated as the brake pedal 12 is operated.
A hydraulic chamber 14 and a second hydraulic chamber 16 are provided.
The hydraulic pressure chamber 14 is connected to the wheel cylinder 18 of the front wheel brake, and the second hydraulic chamber 16 is connected to the wheel cylinder 20 of the rear wheel brake with an electromagnetic on-off valve 22 which is a hydraulic pressure control valve.
connected via. The vehicle includes a deceleration sensor 24 that outputs a deceleration signal 8G representing the deceleration of the vehicle, and a front load signal FW and a rear load signal that detect the loads on the front and rear wheels of the vehicle and represent the front and rear wheel loads. A front wheel load sensor 26 and a rear wheel load sensor 28 that each output RW are provided.

The deceleration signal 8G, front load signal FW and rear load signal RW are supplied to a control circuit 80 which is a control device, and a suppression signal SL is sent from the control circuit 30 to the electromagnetic on-off valve 22.
It is now output to .

The control circuit 80, as shown in FIG.
A converter 34 is provided.

Similarly, the front wheel load sensor 26 and the rear wheel load f, sensor 2
Front load signal FW and rear load signal RW output from 8
is supplied to the A/D converter 34 via low-pass filters 36 and 38. Those low pass filters 82.8
6.88 is a low-pass active filter for noise removal consisting of an operational amplifier, a capacitor, a resistor, etc.

The A/D converter 84 converts an analog signal into a digital code signal, and receives the input deceleration signal 8G.
, converts the front load signal FW and rear load signal RW into digital code signals, and outputs the C through the data bus line.
PU40, RAM42, ROM44, I10 boat 46
supply to.

The CPU 40 is an arithmetic control device that executes arithmetic control according to a program stored in advance in the ROM 44 while utilizing the storage function of the RAM 42.
6 to output a signal to the outside or input an external signal.

A brake switch 48 that is activated in response to the operation of the brake pedal 12 is connected to the I10 boat 46, and a pedal operation signal SP indicating that the brake pedal 12 has been operated is supplied thereto. The suppression signal SL (drive current) is supplied from the I10 boat 46 to the electromagnetic on-off valve 22 via the driver 50.

The electromagnetic on-off valve 22 closes the fluid passage from the second hydraulic chamber 1G of the master 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, as shown in FIG.
A second port 74 that communicates with the boat 72 and the wheel cylinder 20 is formed in a housing 76, and a valve cover 78 is screwed onto the housing 76, thereby forming a valve chamber that connects the first boat 72 and the second port 74. 8° is formed. A poppet valve 86 urged toward a valve seat 84 by a spring 82 is accommodated in the valve chamber 80, and when the poppet valve 86 is seated on the valve seat 84, the second port 74 and the valve chamber 80 are connected. communication is now cut off.

Inside the housing 76, there is a cylindrical solenoid 90 fixed by a lower lid 88 screwed to the bottom of the housing 76, and a non-magnetic material that is liquid-tightly fixed to the lower lid 88 and inserted into the solenoid 90. Sleeve 92 and Sleeve 9
A cylindrical core 94 is provided which is fitted within the poppet valve 2 for axial movement and abuts against 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 82.

Therefore, in the electromagnetic on-off valve 22, when the solenoid 9° is not energized, the poppet valve 86 is separated from the valve seat 84, and the first boat 72 and the second port 74 are communicated with each other.
When the solenoid 9o is energized via the lead IIA92, the core 94 is attracted against the urging force of the spring 96, and the poppet valve 86 is seated on the valve seat 84, and the first boat 72
and the second boat 74 are cut off. Note that the poppet valve 86 is connected to the pressure of the second boat 74 in the valve chamber 8.
When the pressure becomes higher than 0, the electromagnetic on-off valve 22 also has the function of a check valve because it is removed from its seat against the biasing force of the spring 82. The core 94 also has a through hole 98 that passes through it in the axial direction in order to equalize the pressure on both end surfaces.
is formed 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.

As the brake pedal 12 is operated, the control circuit 30 operates according to the flowchart shown in FIG.

That is, first step 81 is executed, and the operating state of the brake switch 48 is determined. Pedal operation signal 8P
If this has not occurred yet, step S1 is repeated. When the brake pedal 12 is operated, a pedal operation signal S is generated.
When P is supplied to the CPU 40 via the I10 boat 46, steps 82 to S5 are sequentially executed.

In step 82, the front wheel load W represented by the front load signal FW and the rear wheel load W1 represented by the rear load signal RW are read, and in step s3, the front wheel load Wf and the rear wheel load W are read.

The corner deceleration X is determined based on . That is, front wheel braking force B with front wheel load Wr and rear wheel load Wr as variables
, and the rear wheel braking force Br; where h is the height of the center of gravity of the vehicle, and l is the wheel pace, both of which are generally constants.

A calculation program is stored in advance in the ROM 44,
From the above relational expression (1), front wheel type Wf and rear wheel load Wr
Based on this, a reference rear wheel braking force when the front wheel braking force is a predetermined constant value A is calculated. Then, a predetermined difference between the standard rear wheel braking force and the corner braking hydraulic pressure is determined so that the corner braking pressure is determined to obtain the desired rear wheel braking force as large as possible while preventing the rear wheels from locking. A certain relationship (corresponding data) shown in No. 5 is stored in the ROM 44, and from this relationship, the corner braking hydraulic pressure corresponding to the voice reference rear wheel braking force calculated above is determined. For example, the above equation (1) is expressed as shown by the two-dot chain line that varies within the range between the solid lines in Figure 6 depending on the load, and the front wheel braking force is set at a predetermined constant value. When A, the reference rear wheel braking force 31,5= is calculated, and the corner deceleration X corresponding to the reference rear wheel braking force is determined from the relationship shown in FIG. In other words, the load condition of the front wheels and rear wheels is determined based on the standard rear wheel braking force.
The turning point deceleration X is determined according to the reference rear wheel braking force.

Then, in step 84, the deceleration G of the vehicle represented by the deceleration signal SG is read, and in step S5
Then, it is determined whether the deceleration G is larger than the corner deceleration X or not. If the deceleration G is still smaller than the corner deceleration 0 When the operation of the brake pedal 12 is released and the pedal operation signal 8P disappears, the operation state of the electromagnetic on-off valve 2 is determined.
Open 2! The process is executed again from step 81 via step S8 in which the brake pedal 12 is held.
If the operation continues and the pedal operation signal SP continues to be generated, the process is executed again from step S4.

While the above operations are repeated at high speed, when the braking effect of the vehicle becomes large and the deceleration G exceeds the corner deceleration X, steps S9 and S7 are immediately executed. That is,
In step S9, the suppression signal SL is
6 to the electromagnetic on-off valve 22 via the driver 50, and is supplied from the second hydraulic pressure chamber 16 to the wheel cylinder? A small amount of the brake fluid pressure supplied to the wheel cylinder 20 is blocked by the electromagnetic on-off valve 22, and thereafter, an increase in the brake fluid pressure of the wheel cylinder 20 is suppressed, and the same operation as described above is performed from step 87 onwards. It is.

Therefore, since the corner deceleration X is determined based on the predetermined constant relationship shown in FIGS. 5 and 6, the ideal curve A distribution of front wheel braking force and rear wheel braking force that approximates # (shown by the solid line) can be obtained, and a desirable rear wheel braking force can be obtained according to the load conditions of the front wheels and rear wheels. The relationship between the braking force of the brake and the braking fluid pressure supplied thereto is approximately proportional.

In this way, according to this embodiment, the corner deceleration is determined based on the front load signal FW and the rear load signal RW, so even if the positions where the loads are loaded are different, the load This allows the desired rear wheel braking force to be obtained. Moreover, since the deceleration of the vehicle is detected by the deceleration sensor 24, which is not related to the fluid passage that transmits the brake fluid pressure, the deceleration can be detected accurately regardless of changes in the viscosity of the brake fluid, and the deceleration can be detected accurately without variation. Accurate hydraulic control operation is obtained.

Furthermore, in this embodiment, the electromagnetic on-off valve 22 is configured to open when power is not applied, so even if a failure occurs in the control circuit 80, solenoid 90, etc., operation of the rear wheel brake is ensured, resulting in high safety. There are advantages.

Furthermore, according to this embodiment, the load sensors 26, 28 and the electromagnetic on-off valve 22, which is a hydraulic pressure control valve, have no mechanical relationship with each other and can be installed at their own locations.
It does not need to be attached to the suspension part that detects the load, unlike the conventional live load sensing type Takigawa control valve.

Therefore, it is advantageous that a single type of hydraulic control valve can be used for most vehicle models, without having to make different shapes for each vehicle model.
There is 'rQ.

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 embodiment described by IMJ, the operation of the control circuit 30 in step S3 in FIG. 4 can also be performed as follows.

That is, from equation (1), the front load signal FW, and the rear load signal KW, as shown in FIG. 8, an ideal distribution line (2
A functional relationship represented by a chain of dots #) is specified, and from that functional relationship, a reference rate of change α of the rear wheel braking force when the front wheel braking force is a predetermined constant value A is calculated, and the RO
From the predetermined constant relationship (corresponding data) shown in FIG. 9 between the reference rate of change and the corner deceleration stored in M44, the corner deceleration X corresponding to the reference rate of change & calculated above. may be determined. The above reference rate of change α determines the corresponding rear wheel braking force when the front wheel braking force is a predetermined constant value A, and also determines the front wheel braking force in the relationship shown in FIG. Slightly increase A+ΔA
Then, the rear wheel braking force ΔD can be determined, and the quotient of the increase (ΔD/ΔA) can be found as the reference rate of change α.

In this way, for example, when the live load increases, the reference rate of change α also increases, and at the same time, the corner deceleration X is also changed in the increasing direction, so that the same effect as in the above embodiment can be obtained.

The hydraulic pressure control valve of the above embodiment is configured to block the braking hydraulic pressure supplied to the rear wheel brakes only by the electromagnetic on-off valve 22, but the hydraulic pressure is supplied to the rear wheel brakes as follows. It may also be configured to reduce the brake fluid pressure at a constant rate with respect to the brake fluid pressure of the mask cylinder 10.

In FIG. 10, the decompression device 116 has a first boat 118 and a second boat 120 that are mask cylinders, 10
．． It is connected to the second hydraulic pressure chamber 16 and the wheel cylinder 20 of the rear wheel brake, and is connected in parallel to the electromagnetic on-off valve 22. By screwing the valve cover 124 into the housing 122, 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 128 in the form of a circular hole with an eave formed in the valve cover 124 are formed. A large-diameter piston 182 and a small-diameter piston 184 are slidably fitted into the large-diameter cylinder bore 126 and the small-diameter cylinder bore 128, respectively. Those pistons 182
．． 184 is a spring receiver 13 which is brought into contact with each other and is attached to the cavity 130 side of the large diameter piston 182;
6 and the valve cover 124 is a compression fill spring 188.
is inserted, and the large diameter piston 132 is always urged toward the bottom of the large diameter cylinder bore 126.

Note that the first port 118 and the second boat 120 are a small diameter cylinder bore 128 and a large diameter cylinder bore 12, respectively.
6.

Therefore, when the suppression signal SL is not yet supplied to the electromagnetic opening/closing valve 22, the braking hydraulic pressure in the second hydraulic pressure chamber 16 is directly supplied to the wheel cylinder 20 through the opened electromagnetic opening valve 22, and As the braking fluid pressure increases, the large diameter piston 132 is moved toward the cavity 180 against the biasing force of the compression coil spring 138.

Next, when the suppression signal 8L is supplied and the electromagnetic on-off valve 22 is closed, the pressure applied to the small diameter piston 134 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 the braking fluid pressure generated within the large-diameter cylinder bore 126 as the large-diameter piston 132 moves is applied to the second port 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 pressure supplied to the wheel cylinder 20 is prevented from increasing. Until the increase in the brake fluid pressure is stopped, the large diameter piston 182 moves against the urging force of the compression coil spring 188 according to the magnitude of the brake fluid pressure supplied through the electromagnetic on-off valve 22. Determined by quantity.

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

In FIG. 12, the proportional control valve 140 has a first boat 144 and a second boat 146 provided on its housing 142 and an eighth boat 15 provided on its valve cover 148.
0, the first boat 144 is the mask cylinder 1
0, an electromagnetic on-off valve 22 is connected between the first boat 144 and the second boat 146, and the third port 150 is connected to the wheel cylinder 20 of the rear wheel brake. It is connected. A stepped hole-shaped valve chamber is formed in the housing 142 by screwing the valve lid 148, and a cup-shaped elastic valve seat 152 is disposed in the stepped portion. A valve piston 154 passing through is disposed 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 larger diameter side of the boat 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, thereby forming a spring chamber 162 that separates the valve chamber from the partition wall 160. 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. The valve piston 154 is biased in a direction in which its valve element 156 is moved away from the resilient valve seat 152. And the second boat 146
is communicated with the inside of the cylinder bore 157.

Therefore, when the suppression signal SL is not yet supplied to the electromagnetic opening valve 22, the braking hydraulic pressure in the second hydraulic pressure chamber 16 is supplied to the first boat 144 and the second port 146. For this reason, the piston 164 is moved to the coil spring 168 by the braking fluid pressure supplied through the second port 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 port 144 and the eighth 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 braking fluid pressure supplied to the second boat 146 is prevented from increasing and the movement of the piston 164 is stopped.
A constant bias or force is applied to the pulp piston 154 from the coil spring 168. On the other hand, the first port 1
44 is increased, the pulp piston 154 is moved toward the spring chamber 162 against the biasing force of the coil spring 168, and the valve element 156 is brought into engagement with 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 pulp piston 154 and the biasing force of the coil spring 168 are balanced, and the braking fluid of the eighth boat 150 is adjusted by well-known hydraulic control. pressure is the first
It is increased at a constant rate lower than the rate of increase of the brake fluid pressure in port 144.

As a result, the distribution characteristic shown by the two-dot chain line in FIG. 13 is obtained.

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 master cylinder 10 is transmitted to the wheel cylinder 18 of each wheel by an Of course, the configuration may be such that the information is transmitted to .20. In such a case, it is necessary to connect a hydraulic pressure control valve to each wheel cylinder 20, but according to the hydraulic pressure control device of the present invention, the corner hydraulic pressures of the left and right hydraulic pressure control valves can be matched. Therefore, there is an advantage that the variation in braking force between the left and right rear wheels is almost eliminated.

The electromagnetic on-off valve 22 is connected to the wheel cylinder 2 of the rear wheel brake.
Since it is sufficient that the brake fluid pressure supplied to the valve 0 can be controlled in accordance with the suppression signal SL, there is no problem even if it does not have a check valve function but merely has an opening/closing function.

The control circuit 80 described above can be partially or entirely constituted by a dual-mode microcomputer, and the microphone 4 computer can also be used for other purposes at the same time. Of course, the relationships shown in the figures and FIG. 9 may be non-linear.

In addition, the load sensors 26 and 28 described above detect relative movement between the vehicle body and an unsprung member by utilizing the deformation of the front and rear wheel suspension systems, respectively, or detect relative movement between the vehicle body and the unsprung members, or use pneumatic suspension systems or vehicle height adjustment systems. It may be configured to detect the fluid pressure of each of the front wheels and the rear wheels.

Furthermore, in steps S1 and S2 in the flowchart of FIG. 4, the loads Wf and Wr may be read in advance using other timing signals generated when the vehicle is stable.

It should be noted that what has been described above is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

As detailed above, according to the rear wheel brake hydraulic pressure control device of the present invention, the corner deceleration is determined based on the front wheel load signal and the rear wheel load signal, regardless of the loading position of the cargo. The desired rear wheel braking force can be obtained according to the load being carried. Moreover, since the deceleration of the vehicle is detected by a deceleration sensor that is not related to the fluid passage that transmits brake fluid pressure, deceleration can be detected accurately regardless of changes in the viscosity of the brake fluid, resulting in consistent and accurate detection. The result is a hydraulic control operation.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing the electrical configuration of the embodiment of FIG. 1. FIG. 8 is a sectional view showing the configuration of the electromagnetic M valve used in the embodiment of the first factor. FIG. 4 is a flowchart illustrating the operation of the control device of FIG. 1. 5 and 6 are graphs each showing a predetermined constant relationship used in step S3 of the 70-chart of FIG. 4. FIG. FIG. 7 is a diagram illustrating the operation of the embodiment shown in FIG. 1. FIGS. 8 and 9 correspond to FIGS. 6 and 5 in other embodiments of the present invention. FIG. 10 and FIG. 12 are diagrams each illustrating the configuration of a hydraulic pressure control valve in another embodiment of the present invention. Figures 11 and 13 are similar to Figure 10 and 1.
2 is a graph illustrating the operation of the embodiment shown in FIG.
IO: Mask cylinder 24; Deceleration sensor 26: Front wheel load sensor 80: Control circuit (control device) Applicant Toyota Motor Corporation Fig. 3 8 Fig. 8 MIr*I Gas-Ichiriki (B pipe) Figure 10 Figure 11 Figure 13 Front wheel vP1 power 12th factor 15δ

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 front wheel load sensor detects the load applied to the front wheels of the vehicle and outputs a front load signal representing the load, and a rear wheel load sensor detects the load applied to the rear wheels of the vehicle and outputs a rear load signal representing the load. A sensor, a deceleration sensor that detects vehicle deceleration and outputs a deceleration signal representing the deceleration, and an ideal distribution of front braking force and rear wheel braking force using front wheel load and rear wheel load as variables. A reference rear wheel braking force value is calculated when the front wheel braking force of the vehicle is a predetermined constant value based on the predetermined constant functional relationship expressed and the front load signal and the rear load signal. At the same time, a corner deceleration corresponding to the calculated reference rear wheel braking force is determined based on a predetermined constant relationship between the reference rear wheel braking force and the corner deceleration, and the deceleration signal is a control device that outputs a suppression signal when the deceleration of the vehicle expressed exceeds the turning point deceleration as the deceleration of the vehicle increases; A hydraulic pressure control device for a rear wheel brake, comprising: a hydraulic pressure control valve that suppresses the brake hydraulic pressure supplied from the mask cylinder to the rear wheel brake according to the invention. (2) 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, the vehicle A front wheel load sensor detects the load applied to the front wheels of the vehicle and outputs a front load signal representing the load, and a rear wheel load sensor detects the load applied to the rear wheels of the vehicle and outputs a rear load signal representing the load. A sensor, a deceleration sensor that detects vehicle deceleration and outputs a deceleration signal representing the deceleration, and an ideal distribution of front wheel braking force and rear wheel braking force using front wheel load and rear wheel load as variables. Calculate the reference rate of change in rear wheel braking force when the front wheel braking force of the vehicle is at a predetermined constant value based on the predetermined constant functional relationship expressed and the front load signal and rear load signal. At the same time, a corner deceleration corresponding to the calculated reference rate of change is determined based on a predetermined constant relationship between the reference rate of change in rear wheel braking force and the corner deceleration, and the deceleration is a control device that outputs a suppression signal when the deceleration of the vehicle represented by the signal increases and exceeds the turning point deceleration; and a control device that is inserted in a fluid passage connecting the master cylinder and the rear wheel brake; A hydraulic pressure control device for a rear wheel brake, comprising: a hydraulic pressure control valve that suppresses brake hydraulic pressure supplied from the mask cylinder to the rear wheel brake in accordance with a suppression signal.