JPS6347665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid device for preventing wheels from locking during braking of a two-wheeled vehicle.

Conventionally, anti-skid devices for vehicles detect the rotational state of the wheels, and when the deceleration of the wheels exceeds a predetermined reference value, they reduce the pressure of the fluid that operates the brakes, that is, the brake pressure, and reduce the deceleration of the wheels. When the brake pressure becomes smaller than the reference value, the brake pressure is held constant and then increased.

By the way, a wheel speed detection device that detects the rotational speed of a wheel (hereinafter referred to as wheel speed) has a rotor attached to the wheel side that rotates together with the wheel, whereas a wheel speed detection device that detects the rotational speed of the wheel generates a signal proportional to the rotational speed of the wheel. The device is attached to the vehicle body. Therefore, due to the inertial movement of the vehicle body that occurs when braking,
A relative movement is generated between the wheel side and the vehicle body side, and as a result, a rotational movement is induced between the rotor and the detector. When the braking force increases and the wheel speed tends to decrease, this rotational motion occurs in the direction of decreasing the wheel speed, and when the braking force decreases and the wheel speed tends to recover, this rotational motion occurs in the direction of increasing the wheel speed. Therefore, the change in wheel speed detected by the wheel speed detection device is apparently larger than the actual change in wheel speed. Furthermore, while the actual wheel speed changes without delay in response to changes in braking force, the rotational movement between the wheels and the vehicle body due to the inertial motion is due to the rigidity of the vehicle body.
This occurs with a slight delay in response to changes in braking force. Therefore, due to this delay in rotational movement, the change in wheel speed detected by the wheel speed detection device has a phase lag with respect to the actual change in wheel speed. However, for this change in actual wheel speed,
The amplification and phase delay of changes in wheel speed detected by the wheel speed detection device are small in normal vehicles.

However, in the case of a two-wheeled vehicle, the front wheels are directed by two forks with relatively low rigidity, so the relative movement between the forks and the wheels due to changes in braking force is instantaneous and extremely large, causing the front wheels to move against the rotor. The change in wheel speed detected by the wheel speed detection device attached to the fork or fork connection is amplified to a greater extent than in the case of a normal wheel compared to the actual change in wheel speed, and the phase lag is big. In other words, in the case of a two-wheeled vehicle, the point at which the deceleration, which is the change in wheel speed detected by the wheel speed detection device (hereinafter referred to as deceleration by the wheel speed detection device), decreases to the deceleration reference value is the actual wheel speed. If the deceleration, which is a change in deceleration (hereinafter referred to as actual deceleration), is greater than the point at which the deceleration decreases to the deceleration reference value, a delay of about 90 degrees occurs in terms of phase difference.

However, in conventional anti-skid devices for two-wheeled vehicles, the influence of such amplification and phase delay due to fork on the wheel speed detected by the wheel speed detection device is ignored, and the deceleration of the wheel is determined based on the deceleration standard. The brake pressure continued to drop rapidly until it recovered to the specified value. Therefore, the brake pressure is excessively relaxed from the time when the actual deceleration decreases to the deceleration reference value until the time when the deceleration measured by the wheel speed detection device decreases to the deceleration reference value. Therefore, the brake pressure decreases more than necessary, and as a result, it becomes necessary to rapidly increase the brake pressure, resulting in a large range of change in the brake pressure during anti-skid control. Therefore,
This had the disadvantage that the deceleration change occurring in the vehicle body was large, deteriorating maneuverability and ride comfort.

The present invention has been made in view of the above-mentioned drawbacks, and is based on the assumption that the amplification effect and phase delay of the wheel speed change caused by the fork by the wheel speed detecting device is taken into account, and the deceleration by the wheel speed detecting device is set as the deceleration standard. At the point where the phase is 90 degrees ahead of the point at which the brake pressure decreases to the value, and the rate of change in deceleration becomes zero, that is, at the point when the deceleration reaches the maximum value, the brake pressure is reduced gradually instead of suddenly. The time when the actual deceleration decreases to the deceleration reference value is approximated to the time when the maximum value of the deceleration measured by the wheel speed detection device is reached. That is, a discriminator is provided that generates a deceleration reduction signal when the deceleration of the wheel is reduced, and when the deceleration reduction signal is generated, the brake pressure decrease rate is determined based on the signal when the deceleration reduction signal is not generated. It is an object of the present invention to provide an anti-skid device which is designed to reduce the rate of decrease in brake pressure in comparison with the rate of decrease in brake pressure, thereby preventing brake pressure from decreasing more than necessary.

Hereinafter, details of the present invention will be explained based on illustrated embodiments. In FIG. 1, which shows a control circuit of the brake system according to the embodiment as a block diagram, 1 is a wheel speed detector that generates an output signal with a frequency proportional to the rotational speed of the wheel, and 2 is a wheel speed detector 1.
This is a wheel speed signal generator that receives a signal from the wheel and generates a wheel speed signal V having a magnitude proportional to the wheel speed. 3 is an approximate vehicle speed signal generator, which normally has the same value as the wheel speed signal V, but when the wheel speed starts to decrease at a predetermined deceleration or higher, it decreases at a predetermined slope to approximate the vehicle speed. Approximate vehicle speed signal E
occurs. Reference numeral 4 denotes a slip rate signal generator that generates a slip rate signal S, which compares the wheel speed signal V with the approximate vehicle body speed signal E, and determines whether the wheel speed signal V is a predetermined percentage of the approximate vehicle body speed signal E, for example, 80% or less. In other words, when the slip rate becomes 20% or more, the output slip rate signal S becomes an H signal, and when it is less than 20%, it becomes an L signal. 5 is a differentiator that detects the rate of change of the wheel speed signal V, that is, the acceleration or deceleration. 6 is an acceleration signal generator that generates an acceleration signal +b, which compares the output of the differentiator 5 with a value corresponding to an acceleration reference value of an acceleration of 0.5g, and when the acceleration of the wheel exceeds the reference value, the output is The acceleration signal +b becomes an H signal, and when smaller than the reference value, becomes an L signal. 7 is the deceleration signal -
The output of the differentiator 5 is compared with a value corresponding to a standard deceleration value of 1.5 g of deceleration, and if the deceleration of the wheel exceeds 1.5 g, the output is reduced. The speed signal -b becomes an H signal, and when it is smaller than the reference value, it becomes an L signal. 8 is a differentiator that differentiates the output of the differentiator 5 again in order to judge whether the wheel deceleration is increasing or decreasing; when the wheel deceleration is decreasing, the output signal is H. , that is, a deceleration reduction signal is generated, and when the deceleration signal is not in a decreasing state, it becomes an L signal. 9 is or gate, 1
0 is an AND gate. Reference numeral 11 is an off-delay timer, and when the input signal becomes H, the output signal immediately becomes H, but after the input signal becomes L, the output signal is held at H for a predetermined period of time, for example, 0.3 seconds, and then the output signal is set to L. becomes. 12 is an OR gate in which at least one of the acceleration signal +b, the output signal of the AND gate 10, or the output signal of the OFF delay timer 11 is H.
When this happens, the output signal becomes H. 13 is an amplifying circuit, and when the output signal of the OR gate 12 becomes H, the solenoid 1 of the supply valve 27 shown in FIG.
A current Is is supplied to 4. 15 is a NAND gate, and 16 is a pulse generator. 17 is an up counter, and when the signal at the reset terminal R becomes L, the clock pulse f ₀ from the pulse generator 16 is output.
is counted, and when a predetermined count value is reached, the signal at the output terminal is momentarily set to L, and then counting is started again. 18 is an AND gate, and 19 is a monostable multivibrator that generates a pulse with a predetermined pulse width every time an H signal is received from the AND gate 18. A pulse signal C for reducing the brake pressure stepwise is generated by the pulse generator 16, up counter 17, AND gate 18, and monostable multivibrator 19. 20 is an AND gate, and 21 is an amplification circuit. The amplifying circuit 21 is configured such that the output signal of the AND gate 20 is H.
When this happens, a current Ie is supplied to the solenoid 22 of the discharge valve 28 shown in FIG. 2 to operate the discharge valve 28. Incidentally, a pulse generator 16, an up counter 17, and an AND gate 1 generate the pulse signal C.
8, monostable multivibrator 19, deceleration signal generator 7, OR gate 9, AND gate 10
and AND gate 20 constitute a brake pressure reduction speed changing device. Next, FIG. 2 showing a piping diagram of the brake device will be explained. 25 is a master cylinder, which is connected to a disc brake 30 via a pipe 26, a supply valve 27, a discharge valve 28, and a pipe 29.
It is connected to the hydraulic cylinder 31 of. 32 is a reservoir, and 33 is a hydraulic pump. The reservoir 32 is connected to the discharge port of the discharge valve 28 via a pipe 34 and to the suction port of the pump 33 via a pipe 35. Further, a discharge port of the pump 33 is connected to the pipe 26 via a pipe 36. In a non-operating state where no current is supplied to the solenoid 14 of the supply valve 27 and the solenoid 22 of the discharge valve 28, the master cylinder 25 communicates with the hydraulic cylinder 31.

The operation of the embodiment will be explained with reference to FIG. 1, FIG. 2, and FIG. 3 showing the operation characteristics. now,
When the master cylinder 25 is operated at time _t0 in FIG. 3 and the brake fluid pressure increases along line P, the brake is applied to the wheels and the wheel speed begins to decrease. Then, the wheel speed signal V output from the wheel speed signal generator 2 and the signal V〓 representing the output of the differentiator 5, that is, the acceleration or deceleration, change according to the lines V and V〓. At the same time, the approximate vehicle speed signal E output from the approximate vehicle speed signal generator 3 gradually decreases along line E. When the brake fluid pressure increases and the wheel deceleration becomes larger than the deceleration reference value at time _t1 , that is, the output signal V of the differentiator 5 falls below the reference value -g, the deceleration signal generator 7 deceleration signal-
b becomes H. Therefore, this H signal is transmitted to the OR gate 12 via the OFF delay timer 11, the output signal of the OR gate 12 is set to H, and the amplification circuit 13 supplies the current Is to the solenoid 14.
At the same time, this H signal is transmitted to the OR gate 9, the output signal of the OR gate 9 becomes H, and further,
Since the acceleration signal +b, which is the other input signal of the AND gates 10 and 20, and the output signal C of the monostable multivibrator 19 are both L, the output signals of the AND gates 10 and 20 are set to H. Therefore, the current Ie is applied to the solenoid 22 by the amplifying circuit 21.
is supplied. Therefore, the supply valve 27 and the discharge valve 2
8 operates at the same time, the fluid communication path between the master cylinder 25 and the hydraulic cylinder 31 is cut off, the pressure fluid of the hydraulic cylinder 31 is discharged to the reservoir 32, and the brake fluid pressure of the hydraulic cylinder 31 is reduced. Due to the decrease in brake fluid pressure, the increase in wheel deceleration slows down, and when the deceleration begins to decrease at time _t2 , the output signal of the differentiator 8 becomes H. At this time, since the deceleration signal -b of the deceleration signal generator 7 is H, the output signal of the NAND gate 15 becomes L, and the reset signal R of the up counter 17 becomes L. Then, the up counter 17 counts the clock pulse f ₀ from the pulse oscillator 16, and transmits an L signal to the monostable multivibrator 19 via the AND gate 18 every time the count reaches a predetermined value. The monostable multivibrator 19 receives the signal and generates a single pulse with a predetermined pulse width every time the signal changes from L to H, thereby forming a pulse signal C. Therefore, the output signal of the AND gate 20 is the pulse signal C
Each time becomes H, it becomes L, the solenoid 22 of the discharge valve 28 is demagnetized, the discharge valve 28 is operated intermittently, and the brake fluid pressure is lowered stepwise. The deceleration of the wheel decreases, and at _t3 , the deceleration becomes smaller than the reference deceleration, that is, when the output V of the differentiator 5 becomes higher than the reference value -g, the deceleration signal -b becomes L. . Then, at this time, the wheel speed signal V is larger than the value ηE obtained by multiplying the approximate vehicle speed signal E by a predetermined ratio,
Since the slip rate signal S is L, the output signals of OR gate 9 and AND gates 10 and 20 will be L, demagnetizing solenoid 22 and returning discharge valve 28 to its inoperative position. However, since the output signal of the off-delay timer 11 remains high for a predetermined period of time, the output signal of the OR gate 12 remains high, and the supply valve 27 maintains its operating state. Therefore, the brake fluid pressure is kept constant. Then, the acceleration of the wheel becomes equal to or higher than the acceleration reference value, that is, the output V of the differentiator 5
When becomes above the reference value +g, the acceleration signal +b of the acceleration signal generator 6 becomes H, the H signal is transmitted to the OR gate 12, and the output signal of the OR gate 12 continues to be maintained at H. The wheel speed approaches the vehicle body speed, and at time _t4 , the wheel acceleration becomes smaller than the acceleration reference value, and the acceleration signal +b becomes L.
Then, the output signal of the OR gate 12 becomes L, the solenoid 14 is demagnetized, the supply valve 27 returns to the non-operating position, and the hydraulic pressure in the hydraulic cylinder 31 increases. Note that the delay time of the off-delay timer 11 is such that the output signal reaches L before the acceleration signal +b becomes L.
It is set to be. When the deceleration of the wheels becomes equal to or higher than the deceleration reference value again at time _t5 due to an increase in the hydraulic pressure of the hydraulic cylinder 31, the deceleration signal -
b becomes H, the OR gate 12 and the AND gate 20 become H, the supply valve 27 and the discharge valve 28 are operated, and the brake fluid pressure in the hydraulic cylinder 31 is reduced. When the wheel deceleration passes its maximum value at time _t6 and begins to decrease due to a decrease in brake fluid pressure, the output signal of the differentiator 8 becomes H. Then, the output signal of the NAND gate 15 becomes L, and the up counter 17 and monostable multivibrator 19 operate to generate the pulse signal C, as described above. Therefore, the discharge valve 28 operates intermittently, and the brake fluid pressure decreases stepwise. Then, at time _t7 , when the deceleration of the wheels becomes smaller than the deceleration reference value, the deceleration signal -b becomes L. However, at this time, the wheel speed signal V is smaller than the predetermined ratio value ηE of the approximate vehicle body speed signal E, that is, the slip ratio of the wheels is greater than the reference value, so the slip ratio signal S is at H. Therefore, the output signal of OR gate 9 is H. Then, since the output signal of the monostable multivibrator 19 becomes L, the output signal of the AND gate 20 becomes H again. Therefore, the discharge valve 28 is continuously energized and the brake fluid pressure drops rapidly. Due to a decrease in brake fluid pressure, time ts
When the acceleration of the wheel becomes equal to or higher than the acceleration reference value, the acceleration signal +b becomes H, and the output signal of the AND gate 10 becomes L. Therefore, the output signal of the AND gate 20 becomes L, the discharge valve 28 returns to the non-operating position, and the brake fluid pressure is maintained constant. Then, when the wheel speed approaches the vehicle body speed, the wheel acceleration becomes smaller than the acceleration reference value again, and the acceleration signal +b becomes L, the supply valve 27 also returns to the non-operating position and the brake fluid pressure increases again. Thereafter, by repeating the above-described operation, the brake fluid pressure is optimally controlled.

As is clear from the above description, the present invention detects whether the deceleration of the wheel detected by the wheel speed detection device is increasing or decreasing after the deceleration of the wheel detected by the wheel speed detection device exceeds the deceleration reference value. When the deceleration is increasing, the brake pressure is decreased rapidly, and when the deceleration is decreasing, the brake pressure is gradually decreased, so that the brake pressure is reduced from the point when the actual deceleration decreases to the deceleration reference value. Until the deceleration measured by the wheel speed detection device decreases to the deceleration reference value, a sudden drop in brake pressure can be prevented, and therefore an unnecessarily low drop in brake pressure can be prevented. Since the speed at which the brake pressure decreases is changed according to the state of change in the brake pressure, excellent effects such as being able to minimize the influence of a phase delay in the wheel speed caused by the wheel speed detection device are achieved.

In addition, in the embodiment, the rate of decrease in brake pressure is reduced by decreasing the brake pressure in steps, but the present invention is not limited to this. A throttle valve may be provided, and when the wheel deceleration reaches its maximum value and begins to decrease, the throttle valve is activated to slow down the decrease in brake pressure.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control circuit of a brake device showing one embodiment of the present invention, FIG. 2 is a piping diagram of the brake device, and FIG. 3 is an operation diagram showing operating characteristics. DESCRIPTION OF SYMBOLS 1...Wheel speed detector, 2...Wheel speed signal generator, 3...Approximate vehicle body speed signal generator, 4...Slip rate signal generator, 5, 8...Differentiator, 6...Acceleration signal generator, 7...Deceleration Signal generator, 13, 21... Amplification circuit, 14, 22... Solenoid, 16... Pulse transmitter, 17... Up counter, 19... Monostable multivibrator, 25... Master cylinder, 27
... Supply valve, 28 ... Discharge valve, 30 ... Disc brake, 31 ... Hydraulic cylinder, 32 ... Reservoir, 33
…Hydraulic pump.

Claims (1)

[Claims] 1 A rotor that rotates together with the wheel, a wheel speed detection device that is attached to a fork or a fork connection facing the rotor and that generates a signal proportional to the wheel speed, and a wheel speed detection device that generates a signal proportional to the wheel speed, and a wheel speed detection device that is installed on a fork or a fork connection part opposite to the rotor, and that detects when the deceleration of the wheel is equal to or higher than a predetermined deceleration reference value. a deceleration signal generator that generates a deceleration signal when the deceleration signal is generated;
The brake pressure on that wheel was reduced2.
An anti-skid device for a wheeled vehicle includes a discriminator that generates a deceleration decrease signal when the deceleration of the wheel decreases, and the discriminator generates a deceleration decrease signal and the deceleration signal generator The vehicle is characterized by being provided with a brake pressure reduction speed changing device that reduces the speed of reduction of the brake pressure during the period when the speed signal is being generated, compared to the speed of reduction of the brake pressure when the deceleration reduction signal is not generated. Anti-skid device for two-wheeled vehicles.