JPS5920507B2 - Anti-skid device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides acceleration and deceleration of wheels! The present invention relates to an anti-skid device for a vehicle in which the slip rate of the wheels is also added to the control factor.

When a vehicle suddenly brakes, if the braking input to the wheels is too large, the wheels lock, which not only reduces braking efficiency but also causes loss of directional stability and steering ability of the wheels.
Very dangerous.

In order to prevent such a dangerous situation, when there is a risk of wheel locking, it is necessary to keep the wheel slip rate within an appropriate range, for example 15 to 25, regardless of the braking input by the driver. It is known that it is sufficient to automatically control the braking torque of the wheels so that it is within a range of approximately 50%.
Therefore, various anti-skid brake devices have been proposed as devices for automatically controlling the braking torque of wheels, but none of them have been satisfactory in terms of performance, reliability, economy, etc. I can't say it's sufficient. In addition, conventional anti-skid devices detect wheel acceleration and deceleration, which is negative acceleration, and apply braking while determining whether there is a risk of wheel locking based on the magnitude of wheel acceleration or deceleration. I try to control the torque, but
If the control method is based only on wheel acceleration/deceleration, it is difficult to control the braking torque so that the wheel slip rate is within an appropriate range under all possible conditions. It is desirable to add slip rate to the control factors. Here, the wheel slip rate is defined as λ=1-Vw/V, where λ is the wheel slip rate, Vw is the circumferential speed of the wheel, and v is the vehicle body speed, but it is clear from this equation that As such, there is no direct relationship between the slip rate λ of the wheel and the differential value Vw of the wheel acceleration, that is, the wheel circumferential speed Vw.

Therefore, in order to detect the slip rate during braking, it is first necessary to detect the vehicle speed at that time. Conventionally, methods for detecting vehicle speed include (1) detection using a Doppler radar installed on the vehicle; (2) non-braking wheels are specially installed and vehicle speed is detected from the circumferential speed of the wheels. (3) A method of detecting the acceleration/deceleration of the vehicle body and calculating the vehicle speed from the integral value, etc., but these conventional methods have complicated structures and lack accuracy and reliability. It is difficult to obtain a vehicle speed detection device that is technically and economically satisfactory due to insufficient performance, or the number of parts and processing and assembly man-hours are large. In consideration of the actual situation, the present invention adds the slip rate of the wheels as well as the acceleration/deceleration of the wheels to the control factors, so that the slip rate of the wheels is always within an appropriate range under all assumed conditions. The main object of this invention is to obtain an anti-skid device for a vehicle that can control braking torque.

Another object of the present invention is to estimate the vehicle speed based on the circumferential speed of the wheels, obtain a slip rate from the estimated vehicle speed and the circumferential speed of the wheels, and calculate the slip rate and the acceleration/deceleration of the wheels. An object of the present invention is to obtain an anti-skid device for a vehicle that can determine the control timing of braking torque by combining them as control factors.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, a brake pedal 1 is operatively connected to a master cylinder 2, and when the driver depresses the brake pedal 1, The master cylinder 2 is designed to generate braking oil pressure.

The master cylinder 2 communicates via an oil passage 3 with a brake oil chamber 11 formed between a pair of pistons 7 and 8 in a wheel cylinder 6 mounted on a vehicle body. Each piston 7
, 8 extend outwardly through the end wall of the wheel cylinder 6, and the outer ends of each rod 9, 10 are in frictional contact with the brake drum 4 mounted on the wheel. The brake shoes 5 and 5' are respectively connected to a pair of brake shoes 5 and 5' which generate braking torque. Therefore, when the master cylinder 2 generates braking oil pressure when the brake pedal 1 is depressed, this braking oil pressure flows through the oil path 3.
As a result, the pistons R and 8 are pressed and moved in the direction away from each other, and accordingly, each brake shoe 5 and 5' is transferred to the brake drum 4.
is pressed toward the friction surface of the brake drum 4 to generate braking torque to the wheels in cooperation with the brake drum 4. If the brake oil pressure in the brake oil chamber 11 is too large, each brake shoe 5, 5'
The braking torque generated between the brake drum 4 and the brake drum 4 is too large, and as a result, the wheels become locked. In order to prevent this dangerous situation, a pair of control oil chambers 12, 12' are formed between each piston 7, 8 and the end wall of the wheel cylinder 6. By controlling the control oil pressure in the control oil chamber 11, when the brake oil pressure in the control oil chamber 11 is too large and there is a possibility or danger of wheel locking, the movement of each piston 7.8 by the brake oil pressure is suppressed. It is configured as follows. Therefore, a control device for controlling the control oil pressure in the control oil chambers 12, 12' will be explained below.

The pressurized control oil sucked up from the oil tank T by the pump p passes through the oil line 15 and the pressure accumulator 13, and is then sent to the electromagnetic coil 2.
0, and the outlet side boat of the inred valve 14 is fed to the control oil chamber 12 via an oil passage 16, and further to an oil passage 17. The control oil chambers 12' are communicated with each other through the respective control oil chambers 12'. In addition, the control oil chamber includes an oil passage 16,
The control oil chamber 12' communicates with the inlet side boat of the outlet valve 19, which is switched and controlled by the electromagnetic coil 21, through the oil passages 17 and 18, and the control oil chamber 12' through the oil passage 18. The outlet side boat of the valve 19 communicates with the oil tank T. inred valve 14
are normally held in the right-hand position in FIG. 1, and in this state, each control oil chamber 12,
12' is isolated from pump p and pressure accumulator 13.

When the electromagnetic coil 20 is actuated by a signal sent to the electromagnetic coil 20, the inlet valve 14 is switched to the left position in FIG. The oil is forced into each control oil chamber 12, 12' through the inlet valve 14, and pushes each piston 7, 8 toward each other against the control oil pressure in the control oil chamber 11. Further, the outlet valve 19 is normally maintained in the left position in FIG. has been done.

When the electromagnetic coil 21 is activated by a signal being sent to the electromagnetic coil 21, the outlet valve 19
is switched to the right-hand position in FIG. 1, so that each control oil chamber 12, 12' is isolated from the oil tank T. Therefore, as the second operating state, the inlet valve 14 is switched to the right position and the outlet valve 19 is switched to the left position, that is, each electromagnetic coil 20,
Considering the state in which no signal is sent to any of the control oil chambers 12 and 1γ, in this state, each control oil chamber 12, 1γ is connected to the oil tank T.
Since the pistons 7 and 8 are pressed and moved only depending on the control oil pressure in the control oil chamber 11, the braking torque during braking is freely increased according to the driver's braking operation. do.

Next, as a second operating state, the outlet valve 19
is switched to the right position, that is, electromagnetic coil 2
Considering the state in which the signal is sent to 1, in this state, each control oil chamber 12, 12' is cut off from the oil tank T, and the control oil in each control oil chamber 12, 12' is in a locked state. Therefore, each piston 7, 8 is restrained from further movement even if the control oil pressure in the control oil chamber 11 continues to increase.

As a result, the control torque during braking is held constant regardless of the driver's braking operation, so that this second operating state is suitable in the event of a possible locking of the wheels. Then, as the third operating state, the inlet valve 1
4 is switched to the left position and the outlet valve 19 is switched to the right position, that is, each electromagnetic coil 2
Considering the state in which signals are sent to both ports 0 and 21, in this state, the control oil sent from the pump P passes through the pressure accumulator 13 and the inlet valve 14 to the control oil chambers 12 and 1.
2' and each control oil chamber 12, 12'.
are cut off from the oil tank T, so the pistons 7 and 8 are pushed toward each other against the control oil pressure in the control oil chamber 11.

As a result, the braking torque during control is reduced independently of the driver's control actions, so that this third operating state is suitable if there is a risk of wheel locking. By the way, in order to find the slip rate of the wheels, it is first necessary to estimate the vehicle speed, and for this purpose, a practical vehicle speed estimation device 3
A specific example of No. 2 will be described below with reference to FIGS. 2 and 3.

First, in FIG. 2, each wheel has wheel speed detection devices 22, 23 that individually detect the circumferential speed of the corresponding wheel.
24 and 25, each wheel speed detection device 22, 23
, 24 and 25 each output a wheel speed signal having a value proportional to the circumferential speed of the corresponding wheel as a frequency signal Fl. Occurs as f2, f3 and F4. Each wheel speed frequency signal Fl,
f2, f3, and f4 are immediately connected to frequency-to-voltage converters 26, 27, and 27, respectively, in order to convert them into easy-to-handle signals.
28 and 29, where voltage signals UW,, UW2, UW3 and U are respectively proportional to the circumferential speed of each wheel.
Converted to W4. In Fig. 3, each wheel speed voltage signal U
The state of change in the values of Wl, UW2, UW3, and UW4 with respect to time during braking is exemplarily shown. Referring again to FIG. 2, each frequency-to-voltage converter 26, 27, 2
The wheel speed voltage signal UWl,U which is the output signal of 8,29
W2, UW3, and UW4 are subsequently sent to the high select circuit 30, respectively.

The high select circuit 30 always selects only the signal having the maximum value among the wheel speed voltage signals UWl, UW2-UW3, and UW4 received as input signals, and selects the signal with the highest value as shown by the thick solid line in FIG. Wheel speed voltage signal 1J
wrnax is generated as an output signal. Maximum wheel speed voltage signal Uwrn generated by high select circuit 30
a) c & ma, then sent to a memory circuit 31 having constant current discharge characteristics commensurate with standard vehicle body deceleration during braking. The memory circuit 31, as shown by the chain line in FIG.
For the input signal, the maximum wheel speed voltage signal b, oil a,
An estimated vehicle speed voltage signal U, which is a damping signal having a slope determined by the discharge characteristics of the storage device, is generated as an output signal. The vehicle body speed voltage signal U estimated in this way is applied to the reference wheel speed setting circuit 3 as shown in FIG.
Sent to 3.

The reference wheel speed setting circuit blade has a predetermined slip rate λ with respect to the estimated vehicle speed voltage signal U. This circuit sets the wheel speed such that the reference wheel speed voltage signal UR is set.

Since the reference wheel speed is set as described above, a specific example of a method and device for adding the wheel slip rate to the control factor in the anti-skid device will be described below. In FIG. 4, the circumferential speed of a wheel whose braking torque is to be controlled is first detected by a wheel speed detection device 34 attached to the wheel.

The wheel speed detection device 34 generates a wheel speed frequency signal fl having a value proportional to the wheel speed as its output signal, but this signal is immediately converted into a wheel speed voltage signal having a value proportional to the wheel speed by the frequency-to-voltage converter 35. Converted to Uwi. In order to obtain this wheel speed voltage signal (1), each wheel speed detecting device 22, 23 constituting the vehicle speed estimating device 32 shown in FIG. , 24, 25 and each frequency -
The voltage converters 26, 27, 28, 29 can be used for each wheel. Wheel speed voltage signal
is subsequently sent to a proportional circuit 36, a differentiating circuit 37 and a comparing circuit 38.

The comparison circuit 36 compares the wheel speed voltage signal Uwi with the reference wheel speed voltage signal U which is the output signal of the reference wheel speed setting circuit 33. The value of the wheel speed voltage signal Senmura is the reference wheel speed voltage signal U. When it is smaller than the value of
It is configured to generate an output signal only when <UR. Differentiator circuit 37 differentiates wheel speed voltage signal Uwi and generates wheel acceleration voltage signal Hi as an output signal.

Then, this wheel acceleration voltage signal [1Twi is immediately sent to comparison circuits 40, 41 and 42. Here, the comparison circuit 40 compares the wheel acceleration voltage signal 0wi with a reference wheel deceleration voltage signal WO indicating a preset negative reference wheel acceleration, and determines that the value of the wheel acceleration voltage signal 0W1 is the reference wheel deceleration signal WO. When the speed voltage signal is smaller than the value of -VwO,
That is, it is configured to generate an output signal only when Uwi<-VvO. Further, the comparison circuit 41 compares the wheel acceleration voltage signal i with a preset first reference wheel acceleration voltage signal W1, and determines that the value of the wheel acceleration voltage signal deviation 1 is equal to the first reference wheel acceleration voltage signal VWl. It is configured to generate an output signal only when it is larger than the value, that is, when W1<n.

Furthermore, the comparison circuit 42 compares the wheel acceleration voltage signal O shoulder with the wheel acceleration voltage signal O shoulder;
The first reference wheel acceleration voltage signal W2 is compared with a preset second reference wheel acceleration voltage signal W2 having a larger value than the first reference wheel acceleration voltage signal W2, and the value of the wheel acceleration voltage signal is compared to the second reference wheel acceleration voltage signal. It is configured to generate an output signal only when the value of W2 is greater than the value of W2, that is, when the value is zero.

The output side of this comparison circuit 42 is connected to the input side of an inversion circuit 45, and while the comparison circuit 42 is generating an output signal, the inversion circuit 45 cancels the signal and produces no output signal. However, while the comparison circuit 42 is not generating an output signal, it is configured to always generate an output signal. That is, the inversion circuit 45 is the comparison circuit 42
It functions to invert the output signal of By the way, the comparator circuit 38 compares the wheel speed voltage signal Uwi with a preset second reference wheel speed voltage signal VwO indicating an extremely low circumferential speed of the wheel.
The output signal is generated only when the value of VwO is smaller than the value of the second reference wheel speed voltage signal VwO, that is, when 6<VwO.

The output side of this comparison circuit 38 is connected to the input side of a pulse generator 39, and this pulse generator 39 is configured to generate a pulse with a constant time width T immediately after the comparison circuit 38 generates an output signal. has been done. Now, the output signals of the comparison circuits 36, 40, 41, 42 and the pulse generator 39 are determined through a logical judgment process, and the electromagnetic coil 20 for operating the inlet valve 14 shown in FIG.
The signal is sent as an operation command signal to the electromagnetic coil 21 for operating the outlet valve 19, and the logic circuit device therefor will be explained below.

The output sides of the comparison circuits 36 and 40 are both connected to the M1 circuit 43.
and the input side of the 0R circuit 44, and the comparison circuit 41
The output side of the pulse generator 39 is connected to the input side of the 0R circuit 44. The output sides of the AND circuit 43 and the pulse generator 39 are further connected to the input side of the 0R circuit 46, and the output sides of the 0R circuit 46 and the inverting circuit 45 are connected to the input side of the AND circuit 47. .

The output sides of the 0R circuit 44 and the inverting circuit 45 are A
It is connected to the input side of the ND circuit 48. AND circuit 4
7 is connected to the electromagnetic coil 20, and the AND circuit 47
generates an output signal, the electromagnetic coil 20 is actuated to switch the inlet valve 14 from the right-hand position to the left-hand position in FIG.
The circuit 48 is connected to the electromagnetic coil 21 and is configured such that when the AND circuit 48 generates an output signal, the electromagnetic coil 21 is actuated to switch the outlet valve 19 from the left position to the right position in FIG. . Since the logic circuit device is configured as described above, each comparison circuit 36, 40, 41, inversion circuit 45 and pulse generator 3
The processing of the output signal No. 9 is performed as follows.

First, the circumferential speed of the wheel is greater than the reference wheel circumferential speed, which is set extremely low, so the wheel speed voltage signal
Considering a state in which the value of the wheel speed voltage signal Himl is larger than the value of the second reference wheel speed voltage signal VwO and the pulse generator 39 does not generate an output signal, the value of the wheel speed voltage signal Himl is larger than the value of the reference wheel speed voltage signal UR. is also large, and the value of the wheel acceleration voltage signal Tml is greater than the value of the reference wheel deceleration voltage signal WO and smaller than the value of the first reference wheel acceleration voltage signal W1, that is, UR<UWi/). One division 0<T
ml? 1, or when the value of the wheel acceleration voltage signal NWi is greater than the value of the second reference wheel acceleration voltage signal W2 regardless of the value of the wheel speed voltage signal ml, that is, when VW′2<ml, It is determined that there is no possibility of the wheels locking, and both the AND circuits 47 and 48 do not generate output signals. Therefore, at this time, the electromagnetic coils 20 and 21 do not operate together, so the inlet valve 14 and the outlet valve 19 is placed in the first operating state, and the braking torque during braking is freely increased in accordance with the driver's braking operation.

Further, the value of the wheel speed voltage signal shoulder is larger than the value of the reference wheel speed voltage signal UR, and the wheel acceleration voltage signal ml is larger than the value of the reference wheel speed voltage signal UR.
When the value of is smaller than the value of the reference wheel deceleration voltage signal -VwO, that is, when i<-VwO, or when the wheel acceleration voltage signal is 1 regardless of the value of the wheel speed voltage signal is larger than the value of the first reference wheel acceleration voltage signal W1 and smaller than the value of the second reference wheel acceleration voltage signal VW2, that is, VWl<
or when the value of the wheel speed voltage signal Hml is smaller than the reference wheel speed voltage signal U8 and the value of the wheel acceleration voltage signal Bi is larger than the reference wheel deceleration voltage signal WO2. When it is smaller than the reference wheel acceleration voltage signal VW2, that is, Uwi<UR and -vertical WO<
When 0Wi<■JP, it is determined that there is a possibility of wheel locking, and the AND circuit 47 does not generate an output signal, but only the AND circuit 48 generates an output signal.

Therefore, at this time, the electromagnetic coil 20 does not operate, but the electromagnetic coil 21 operates, so that the inlet valve 14 and the outlet valve 19 are placed in the second operating state, and the braking torque during braking is related to the driver's braking operation. It is kept constant so that it does not increase any further. Furthermore, the value of the wheel speed voltage signal Himml is the reference wheel voltage signal U.

is smaller than the value of the wheel acceleration voltage signal [11wi
The value of the reference wheel deceleration voltage signal -<! When it is smaller than the value of WO, that is, Uwi<UR and 0wi<−VwO
When , it is determined that there is a risk of wheel locking, and AND circuits 47 and 48 both generate output signals. Therefore, at this time, the electromagnetic coils 20 and 2
1 are operated together, the inlet valve 14 and the outlet valve 19 are placed in the third operating state, and the braking torque during braking is reduced regardless of the driver's braking operation. By the way, the circumferential speed of the wheels becomes extremely low,
When the value of the wheel speed voltage signal UWl becomes smaller than the value of the second reference wheel speed voltage signal VwO, the comparator circuit 38 generates an output signal, and the pulse generator 39 outputs a pulse with a constant time width T. occurs as.

In such a case, the value of i to the wheel acceleration voltage signal is the second value.
Since it is smaller than the value of the reference wheel acceleration voltage signal W2, and therefore the inverting circuit 45 is generating output signal 1,
AND circuits 47 and 48 (tRegardless of the output signals of each comparison circuit 36, 40 and 41, both pulse generator 39
The output signal is generated only during the time width T of the pulse that is generated. Each electromagnetic coil 20, 2 only during this time width T.
1 are operated together, the inlet valve 14 and the outlet valve 19 are placed in the third operating state, and the braking torque during control is reduced regardless of the driver's braking operation. The comparator circuit 38 and the pulse generator 38 are configured to detect, for example, when the vehicle suddenly enters a road surface with a low friction coefficient from a road surface with a high friction coefficient while braking, the wheels may momentarily lock due to a delay in response of the control system. Even if this happens, it immediately releases it and functions as an additional circuit to reliably prevent continued wheel locking.

Comparison circuit 38 and pulse generator 39 shown in FIG.
A dividing circuit 49 and a comparing circuit 50 as shown in FIG. 5 can be provided to perform the same functions as those shown in FIG.

5, instead of providing the comparator circuit 38 and pulse generator 39 in FIG.
3, and in this dividing circuit 49, a low reference wheel speed voltage signal Ud having a value much smaller than the value of the reference wheel speed voltage signal j than the estimated vehicle speed voltage signal U is set. At the same time, this low reference wheel speed voltage signal U (is sent to the comparator circuit 50 as an output signal of the dividing circuit 49, and the comparator circuit 50 outputs the wheel speed voltage signal U).
l and the low reference wheel speed voltage signal Ud, and generates an output signal only when the value of the wheel speed voltage signal Hml is smaller than the value of the low reference wheel speed voltage signal Ud, and sets it to 0.
The difference from FIG. 4 is that the signal is sent to R circuits 44 and 46, but the rest of the configuration is exactly the same as FIG. 4. Therefore, in the circuit device shown in FIG. 5, when the value of the wheel speed voltage signal becomes smaller than the value of the low reference wheel speed voltage signal, that is, Uwi<Ud.
When this happens, the electromagnetic coils 20 and 21 operate together, and the inlet valve 14 and outlet valve 1
9 is placed in the third operating state, and the braking torque during braking is reduced regardless of the driver's braking operation.

FIG. 6 shows an example of the operation mode of the anti-skid device when the logic circuit device shown in FIG. 4 is employed.

In this FIG. 6, the horizontal axis shows the passage of time after the start of braking, and the vertical axis shows the estimated vehicle speed voltage signal U, the wheel speed voltage signal shoulder, and the reference wheel speed voltage at the top position. A signal UR is shown, in its lower position,
i is shown in the wheel acceleration voltage signal, and below it, in order, the output signal A of the comparison circuit 36, the output signal B of the comparison circuit 40, the output signal C of the comparison circuit 41, the output signal D of the comparison circuit 42, The third operating state (2), the second operating state (2), the first operating state 1, and the braking torque TB of the inlet valve 14 and the outlet valve 19 are shown, respectively. Immediately after starting braking at time t-0, neither of the AND circuits 47 and 48 generates an output signal, and therefore the hydraulic control system of the braking device is in the first operating state 1, so the braking torque is TB gradually increases, and along with this, both the wheel speed voltage signal S1 and the wheel acceleration voltage signal SWI gradually decrease.

When the value of the wheel acceleration voltage signal shoulder becomes smaller than the value of the reference wheel deceleration voltage signal WO at time t1, the output signal B of the comparator circuit 40 is generated, indicating that there is a possibility of wheel locking. The judgment is made and the AND circuit 48 generates an output signal, but since the output signal A of the comparison circuit 36 has not yet been generated at this time, the AND circuit 47 does not generate an output signal and the hydraulic control system of the braking device is operated by the second In the operating state (2), the braking torque TB is kept constant.

At this time, the braking torque TB may increase due to a delay in the operation of the hydraulic control system, etc.
Since has become excessive, the wheel speed voltage signal ml continues to decrease further, and as a result, the comparator circuit 36 generates an output signal A at time T2. At this point, the comparison circuit 36
The output signal A of the comparator circuit 40 and the output signal B of the comparator circuit 40 are generated together, and it is determined that there is a risk of wheel locking, so the AND circuits 47 and 48 generate output signals together, and each electromagnetic The coils 20 and 21 operate together, and the hydraulic control system enters the third operating state (2), and the braking torque TB is reduced. As the braking torque TB decreases, the acceleration of the wheels gradually increases, and as a result, at time T3, the value of the wheel acceleration voltage signal 1 becomes larger than the value of the reference wheel deceleration voltage signal WO for comparison. The output signal B of the circuit 40 disappears, and it is determined that the risk of wheel locking disappears, and the output signal of the AND circuit 47 disappears, but the output signal A of the comparator circuit 36 continues to be generated.
The output signal of circuit 48 does not disappear.

Therefore, the hydraulic control system is again in the second operating state ■.
Braking torque TB is held approximately constant. At this time, since the braking torque TB has decreased too much due to the delay in the operation of the hydraulic control system, the wheel acceleration voltage signal [11wi] continues to rise, and the wheel speed voltage signal begins to rise, and at time T4, the wheel acceleration voltage The value of the signal shoulder becomes larger than the value of the first reference wheel acceleration voltage signal W1, and the output signal C of the comparison circuit 41 is generated, and furthermore, at time T5, the value of the wheel acceleration voltage signal 0wi becomes the second reference wheel acceleration. The output signal D of the comparator circuit 42 is generated as the voltage signal becomes larger than the value of the voltage signal W2.

As a result, it is determined that there is no possibility of the wheels locking, and both the M1 circuits 47 and 48 do not generate output signals, and the electromagnetic coils 20 and 21 are both placed in an inactive state.
The hydraulic control system is in the first operating state 1, and the braking torque T
B begins to increase again. As the braking torque TB increases, the value of the wheel acceleration voltage signal rises at time T6 becomes smaller than the value of the second reference wheel acceleration voltage signal W2, and the output signal D of the comparison circuit 42 disappears. Since the output signal C of the comparison circuit 41 still remains, it is determined that there is a possibility of wheel locking, and the AND
The circuit 48 generates an output signal, the electromagnetic coil 21 is activated, the hydraulic control system enters the second operating state, and the braking torque T
B is kept constant. When the wheel speed voltage signal shoulder increases to the extent that an appropriate wheel slip rate can be maintained, the value of the wheel acceleration voltage signal Uwi changes to the first reference wheel acceleration voltage signal at time T7. The output signal C of the comparator circuit 41 becomes smaller than the value of W1.
disappears, and it is determined that there is no possibility of wheel locking, and AND circuits 47 and 48 do not generate output signals, and both electromagnetic coils 20 and 21 are placed in an inactive state, and hydraulic control is performed. The system enters a first operating state 1 and the control torque TB begins to increase.

Thereafter, the above process is repeated in the same way, and the vehicle speed decreases without the wheels locking.

In the above description, the wheel cylinder 6 mainly constitutes the braking device of the present invention, the inlet valve 14 and the outlet valve 19 cooperate with each other to constitute the braking force control actuation device of the present invention, and the divided circuit 33 constitutes the braking force control actuation device of the present invention. The wheel speed detecting device 34 and the frequency-to-voltage converter 35 cooperate with each other to constitute the wheel speed signal generating device of the present invention, and the AND circuits 43, 47,
48, the 0R circuits 44, 46, and the inverting circuit 45 cooperate with each other to constitute a logic circuit device of the present invention, and the estimated vehicle speed voltage signal U constitutes the estimated vehicle speed signal in the present invention, and the reference wheel speed voltage Signal U.

constitutes a reference wheel speed signal in the present invention, wheel speed voltage signal SEN1 constitutes a wheel speed signal in the present invention,
The wheel acceleration voltage signal PI constitutes the wheel acceleration signal in the present invention, the reference wheel deceleration voltage signal -VwO constitutes the reference wheel deceleration signal in the present invention, and the first reference wheel acceleration voltage signal r1 constitutes the wheel acceleration signal in the present invention. constitutes a first reference wheel acceleration signal at W, and further comprises a second reference wheel acceleration voltage signal W.
2 constitutes the second reference wheel acceleration signal in the present invention. As described above, according to the present invention, the wheel slip rate is added to the control factors as well as the wheel acceleration/deceleration, so that the wheel slip rate is always within an appropriate range under all assumed conditions. Thus, an anti-skid device for a vehicle can be obtained which can control braking torque in a manner similar to that described above.

In particular, in the present invention, the braking force control actuating device is configured to have three operating states, one of which is an operating state that maintains the braking force of the wheels constant. Therefore, it is possible to smoothly control the braking force while automatically checking the operating effect of the braking force control actuating device.As a result, it is possible to suppress the occurrence of vibration as much as possible and prevent damage to related equipment. be able to.

In addition, when estimating the vehicle speed, the vehicle speed is estimated based on the circumferential speed of multiple wheels.
A very practical vehicle speed estimating device can be employed, and the accuracy of the estimated value can be improved by increasing the number of times the estimated value is corrected.

Furthermore, a first comparison circuit for comparing the wheel speed signal and a reference wheel speed signal, and second, third, and third comparison circuits for comparing the wheel acceleration signal and various preset reference wheel acceleration/deceleration signals. and a fourth comparison circuit,
A logic circuit device is provided that logically processes the output signals of each comparison circuit to generate a command signal for operating the braking force control actuating device. In addition, the generation timing of the control force can be automatically and precisely determined.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional conceptual diagram of main parts showing a wheel braking device and a hydraulic control device for controlling the braking torque of the braking device;
FIG. 2 is a block diagram showing an example of a vehicle speed estimation device,
3 is a graph diagram for explaining an example of the operation of the vehicle speed estimating device shown in FIG. 2, FIG. 4 is a signal processing circuit and logic circuit diagram for operating the hydraulic control device shown in FIG. 1, and FIG. The figure is a signal processing circuit and logic circuit diagram similar to that in FIG. 4 showing a modification of FIG. 4, and FIG. 6 is a diagram of the braking device and hydraulic control device in FIG. It is an explanatory view showing an example of each operation mode with a circuit device. 6... Braking device, 14, 19... Braking force control actuation device, 32... Vehicle speed estimation device, 33... Reference wheel speed setting circuit, 34, 35... Wheel speed signal generation device , 36, 40, 41, 42...comparison circuit, 37...
・Differential circuit, 43-48...logic circuit device, U...
Estimated vehicle speed signal, UO...Reference wheel speed signal, Uw
i...wheel speed signal, shoulder...wheel acceleration signal, -
VwO...Reference wheel deceleration signal, W1...First reference wheel acceleration signal, Vol....Second reference wheel acceleration signal.

Claims (1)

[Claims] 1. When braking a wheel, in a first operating state, the braking force of the wheel is increased, in a second operating state, the braking force of the wheel is kept constant, and in a third operating state, the braking force of the wheel is increased. braking force control actuation devices 14, 19 that act on the braking device 6 of the wheels so as to reduce the braking force; and a wheel speed signal generator that detects the peripheral speed of the wheels and generates a wheel speed signal Uwi. devices 34 and 35, a wheel speed estimating device 32 that estimates a vehicle speed U based on the circumferential speeds of a plurality of wheels, and a wheel speed estimation device 32 that estimates a vehicle speed U based on the circumferential speed of a plurality of wheels, and a wheel slip that is preset to the vehicle speed U estimated by this vehicle speed estimation device. a reference wheel speed setting device 33 that generates a reference wheel speed signal U_R by considering the ratio; a differentiation circuit 37 that derives a wheel acceleration signal ■wi from the wheel speed signal Uwi; a first comparison circuit 36 that compares the wheel speed signal Uwi with the reference wheel speed signal U_R and generates an output signal only when the value of the wheel speed signal Uwi is smaller than the reference wheel speed signal U_R;
wi and a reference wheel deceleration signal which is a negative reference acceleration signal.
■ A second comparison circuit 40 that generates an output signal only when the value of the wheel acceleration signal ■wi is smaller than the value of the reference wheel deceleration signal -■wo by comparing the wheel acceleration signal ■wo; and the wheel acceleration signal ■ wi and the first reference wheel acceleration signal ■wi, which is a positive reference acceleration signal, are compared, and the value of the wheel acceleration signal ■wi is determined to be the first reference wheel acceleration signal ■w_1.
a third comparator circuit 41 that generates an output signal only when the value is larger than the value of the wheel acceleration signal ■wi and the first
By comparing the reference wheel acceleration signal ■w_1 with a second reference wheel acceleration signal Vw_2 having a larger value, it is determined that the value of the wheel acceleration signal ■wi is the second reference acceleration signal ■w_
2, which generates an output signal only when the value of
, the value of the wheel speed signal Uwi is larger than the value of the reference wheel speed signal U_R, and the value of the wheel acceleration signal ■wi is equal to the reference wheel deceleration signal -■.
The first reference wheel acceleration signal is larger than the value of wo.
When the value of the wheel acceleration signal ■wi is smaller than the value of the second reference wheel acceleration signal ■w_2, regardless of the value of the wheel speed signal ■wi, the braking force control The actuating devices 14, 19 are
The value of the wheel speed signal Uwi is greater than the value of the reference wheel speed signal U_R, and the value of the wheel acceleration signal ■wi is greater than the value of the reference wheel deceleration signal −■wo. or when the value of the wheel acceleration signal ■wi is greater than the value of the first reference wheel acceleration signal ■w_1 and the value of the second reference wheel acceleration signal ■w_2, regardless of the value of the wheel speed signal Uwi. or when the wheel speed signal Uwi is smaller than the reference wheel speed signal U_R and the wheel acceleration signal Uwi is larger than the reference wheel deceleration signal ■wo and smaller than the second reference wheel acceleration signal ■w_2. The braking force control actuation devices 14 and 19 are set to the second operating state, and further, the value of the wheel speed signal Uwi is smaller than the value of the reference wheel speed signal U_R, and the value of the wheel acceleration signal Uwi is set to the second operating state. Reference wheel deceleration signal -
(2) When the value of wo is smaller than the value of An anti-skid device for a vehicle, comprising logic circuit devices 43 and 48 that generate command signals to operate braking force control actuation devices 14 and 19.