JPS60209366A - Control unit for power steering device - Google Patents

Abstract

PURPOSE:To improve driving safety in time of trouble happening in a sensor, by setting oil flow to an optimum value at that point of time at a time when one or more than two running condition sensors to be used for controlling the oil flow fails to generate any signals. CONSTITUTION:A device bearing the above caption controls a solenoid coil 7 of an oil flow control valve inside an oil passage by means of a control circuit 8 where each output signal out of running condition sensors with a car speed signal generating circuit 1 is inputted, a steering signal generating circuit 2 and unillustrated heavy and light load detecting circuits and also controls an oil quantity to be fed to a power steering. In this case, the control circuit 8 is provided with a momentary car speed operational circuit 80, a mean car speed operational circuit 81 and a mean steering quantity operational circuit 82 or the like. And, when any of the said running condition sensors fails to generate any signals, oil flow is set to an optimum value at that point of time, and constituted so as to output an oil flow setting signal to a solenoid coil drive circuit 6 via a digital to analog converter 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control device for a power steering device that takes into consideration safety measures in the event of a failure.

[Prior art]

In general, a power steering device uses a solenoid pulp to control the flow rate of oil supplied from an oil pump to a power steering section according to driving conditions, so that a light steering force can be obtained over a wide range of driving speeds. There is.

However, in such a conventional device, if a sensor that detects running conditions fails, the oil flow rate is set to the maximum value or the minimum value, making it difficult to operate. For this reason, the solenoid pulp holds the plunger in a position where the oil flow becomes an intermediate flow when no electricity is applied.
It is conceivable to control the moving direction of the plunger to increase or decrease the oil flow rate, but such solenoid pulp not only has a complicated structure, but also requires delicate preparation, and is poor in economy and stability. There is a problem with becoming.

[Object and structure of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a control device for a power steering device that takes measures against failure of a sensor for detecting running conditions, and also ensures economic efficiency and stability. .

In order to achieve such an object, the present invention reads the oil flow rate corresponding to the vehicle speed from an oil flow decoder, corrects this oil flow rate according to the driving conditions, and adjusts the oil flow rate from the sensor that detects the driving conditions. When a signal cannot be obtained, the oil flow rate is controlled to the optimum value at that time. Hereinafter, the present invention will be described in detail using drawings showing embodiments.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, numeral 1 denotes a vehicle speed signal generating circuit, which generates a vehicle speed signal whose pulse number changes depending on the vehicle speed. Reference numeral 2 is a steering signal generating circuit which generates a steering signal with a number of pulses corresponding to the amount of steering. 3 is a heavy load detection port/path, which generates a heavy load signal of "0" level when the load value is larger than a predetermined value, and 4 is a light load detection circuit, which generates a heavy load signal of the predetermined value. When the load value is smaller than [(It is designed to generate a light load signal on a monthly level. 5 is a 17A conversion circuit, 6
is a solenoid coil drive circuit, 7 is a solenoid coil, and the solenoid coil drive circuit 6 is a D/A conversion circuit 5.
The duty ratio of the output signal is controlled according to the voltage supplied from the solenoid coil 7, and the duty ratio of the output signal is also controlled according to the value of the current flowing through the solenoid coil 7. Further, the solenoid coil T controls a valve (not shown) provided in the oil passage according to the duty ratio of the signal supplied from the solenoid coil drive circuit 6, thereby controlling the amount of oil supplied to the power steering device. It looks like this. Reference numeral 8 indicates a control circuit, and reference numeral 9 indicates an attached circuit. The control circuit 8 generates an oil flow rate setting signal for controlling the oil flow rate supplied to the power steering device according to the vehicle speed signal and the steering signal, and supplies the signal to the direct converter 5. At the same time,
The oil flow rate setting signal is corrected based on the load value. Further, the control circuit 8 includes a vehicle speed signal generation circuit 1. which is a driving condition sensor. Steering signal generation circuit 22 Heavy load detection circuit 3. When any of the light load detection circuits 4 no longer generates a signal, the oil flow rate is set to the optimal value at that time. The attached circuit 9 generates an initial reset signal IR, a clock signal CL, and a manual control signal MC for adjusting the steering force according to the driver's preference.

In order to realize the above-mentioned functions, the control circuit 8 includes an instantaneous vehicle speed calculation circuit 80 that calculates an instantaneous vehicle speed signal from the pulse signal period generated from the vehicle speed signal generation circuit 1;
an average vehicle speed calculation circuit 81 that calculates an average vehicle speed signal per second;
An average steering amount calculation circuit 82 that calculates an average steering signal for 30 seconds based on the steering signal, and a load detection circuit 83 that generates a load signal based on the signals generated from the heavy load detection circuit 3 and the light load detection circuit 4. , from the relative relationship between the average vehicle speed signal and the average steering amount signal, generates a driving condition signal that indicates whether the road is in an urban, suburban, or high-speed condition (however, when the average steering amount value is zero, a driving condition decoder 84 (which generates a signal representing an intermediate mode, ie, suburban driving, regardless of the value of the average vehicle speed); an oil flow decoder 85 which decodes an oil flow signal supplied to the power steering device in response to the instantaneous vehicle speed signal; Control pattern decoder 86 that generates a control pattern 4 = one signal to correct the oil flow rate signal from the driving condition signal and the load signal, and an oil flow rate that controls the oil flow rate by adding the oil flow rate signal and the control pattern signal. Oil flow rate setting circuit 8T that generates the setting signal, 1 millisecond which is the operating reference signal for each circuit,
1o IJ seconds, 3 seconds, 10 seconds, and a reference signal generation circuit 88 that generates signals at 30 second cycles, intermediate flow rate setting conditions, that is, a state where no vehicle speed signal is generated and the load condition is changing, which will be described later. A state in which the count value of the 3-second clock counter is 5 (this state will be described later, but it is a state when the vehicle speed state does not occur and three or more steering pulses do not occur in 3 seconds). An intermediate flow rate signal generation circuit 89 that generates a control signal so that the signal sent from the oil flow rate setting circuit 8γ at any time becomes an intermediate flow rate, and a comparison circuit 9 that detects that three or more steering pulses are generated.
Consists of 0.

The instantaneous vehicle speed calculation circuit 80 is composed of an OR circuit 80a, a clock counter 80b1, and a register 80c.The clock counter 80b is incremented every time a signal is supplied to terminal C, and a "1" level signal is supplied to terminal R. The counting results are reset every time. Then, when the register 80c is fully supplied with a signal having a period of less than 1 second to the terminal C and the signal falls twice or more,
Every time that signal falls, the signal that is being supplied to terminal R at that time is captured and stored, and the memorized signal is output, and when a "1" level signal is supplied to terminal R, the stored contents are reset. It looks like this.

The average vehicle speed calculation circuit 81 includes a vehicle speed counter 81a and a delay circuit 81b that delays the input signal by 1 microsecond.
The average steering amount calculation circuit 82 includes a steering counter 82a1, a delay circuit 82b1, and a register 82c. The vehicle speed counter 81a and the steering counter 82a have the same function as the clock counter 80b, and the delay circuit 82b has the same function as the delay circuit 81b.

The load detection circuit 83 includes AND circuits 83a and 83b, and a fall detection circuit 83d1 that generates a pulse signal every time a fall occurs in the vehicle speed signal.When a rise or fall occurs in either the heavy load signal or the light load signal, a pulse is generated. It has a rising/falling detection circuit 83e1 that generates a signal, a counter 83f□, a comparator 83f, a constant generation circuit 83f8, and a terminal C
1-second timer 83f1 load judgment that generates a "1" level output signal when the count value of the counter 83f0 that counts the signal supplied to the constant generating circuit 83f8 exceeds the value representing 1 second output from the constant generating circuit 83f8. Circuit 83h, register 831, falling memory circuit 83j, inverter 83~8
3m1 heavy load counter 83p1 light load kakunta 83q,
It is composed of a delay circuit 83r. counter 83p
, 83q are configured such that when a signal of level "1" is supplied to terminal C, the count value is counted up, and when a signal is supplied to terminal R, the count value is reset. The load determination circuit 83h is configured to determine the load by dividing it into three levels, light, medium, and double, according to the values indicated by the signals supplied to terminals a and b, based on the criteria shown in Table 1 below.

Table 1 Note that when the power is turned on, the register 831 is unconditionally set to the medium load state.

Intermediate flow rate signal generation circuit 89 is 3 second clock counter 8
9a, AND circuits 89b to 89f, inverter asg to
89h, OR circuits 89i to 89, load change memory circuit 8
It is composed of a 9t1 delay circuit 89m. And 3
The second clock counter 89a is configured to count down each time a signal is supplied to the terminal CD, and to count up each time a signal is supplied to the terminal CU, but the counted value is "5" or more. It is configured so that it does not. Moreover, this counter 89a has a count value of "4".
In the following cases, a "0" level signal is output, and when the count value is 5, a "1" level signal is output.

Note that the oil flow rate setting circuit 87 converts the supplied signal into a second
Processing is done based on the priority order and conditions shown in the document.

Table 2 Also, when the oil flow rate setting circuit 87 receives a signal with priority level 2, when the signal supplied to the terminal 87b is at the "1" level, it controls the oil flow rate to an intermediate flow rate, and the oil flow rate is controlled to an intermediate flow rate. When the signal is at the "0" level, the oil flow rate is controlled to the twisting flow rate.

The operation of the device configured in this way is as follows. First, normal operation will be explained. When the automobile starts running, the instantaneous vehicle speed is calculated by the instantaneous vehicle speed calculating circuit 80 based on the vehicle speed signal generated from the vehicle speed signal generating circuit 1.

The operation at this time will be explained with reference to FIG. When the vehicle speed signal shown in FIG. 2 (,) is generated from the vehicle speed signal generation circuit 1,
This signal is sent to the clock counter 8 via an OR circuit 80a.
Since it is supplied to the terminal R of 0b, the clock counter 80
b is reset every time a vehicle speed signal is generated. and,
When the reset is released, the clock counter 80b counts and increments the reference signal supplied to the terminal C every millisecond.

On the other hand, the vehicle speed signal is detected by the fall detection circuit 8 of the load detection circuit 83.
3d, the falling detection circuit 83d generates a pulse every time the vehicle speed signal falls, as shown in FIG. 2(c). The pulse generated by the falling detection circuit 83d is
Since it is supplied to the falling memory circuit 83j and also to the terminal R of the counter 83f0 of the 1-second timer 83f,
The falling memory circuit 83j sends out a "1" level signal as shown at time t1 in FIG. 2(e), and the 1-second timer 83f
Since the counter 83fl is reset, it is shown in Figure 2 (d).
), a signal at the rOJ level is sent out. (In this case, there is no change in level since it is at rOJ level even before reset.) Counter 83f in 1-second timer 83f
Since the reference signal with a period of 1 millisecond is supplied to the terminal C of 0, the counter 83f0 counts up the reference signal when the reset is released. If 1 second or more has passed since the reset was canceled, 1
The count value of the counter 83f0 of the second timer 83f is the comparator 8.
The constant J, which represents that the elapsed time supplied to 3f2 has reached 1 second, is also larger than 1l13f8, so
The one-second timer 83f begins to send out a signal at the "1" level, as shown at time t2 in FIG. Since the level signal is supplied, the output signal of the falling memory circuit 83j, which was at the "1" level as shown at time t2a in FIG. 2, becomes the rOJ level tonal.

The output signal of the falling memory circuit 83j is phase-inverted by the inverter 83m, becomes the "1" level, and is supplied to the instantaneous vehicle speed calculation circuit 80, thereby resetting the clock register 80b and the register 80C. Next, when the vehicle speed signal is supplied at time t2, the fall detection circuit 83d of the load detection circuit 83 generates the pulse shown in FIG. 2(C), so the output signal of the fall memory circuit 83j becomes "1" again. level. If the cycle of the vehicle speed signal supplied during the period from time t2 to time t7 is less than a predetermined period TI (set to 1 second in this example), the register 80c registers the second and subsequent rising edges of the vehicle speed signal. At each downlink time point, the counting result of the clock counter 80b at that time point is taken in and the second
Output as shown in Figure (f). However, time t7 and t
Since the period of 8 is 1 second or more, when 1 second or more elapses from the falling point of time t7, the 1 second timer 83f starts to send out a signal at the "1" level as shown in (d). As a result, the falling memory circuit 83j sends out a "0" level signal as shown in (e), so that the clock counter 80b and the register 80 of the instantaneous vehicle speed calculation circuit 80
c is reset and the output signal of register 80c is (f)
The level becomes "0" as shown in FIG. At time t8, the vehicle speed signal is supplied again, so a state change occurs in the one-second timer 83f and the falling edge detection circuit 83j, but at time t8
Since the period between t9 and t9 is 1 second or more, register 80
c, the output signal does not change during this period.

In this way, when the instantaneous vehicle speed calculation circuit 80 is repeatedly supplied with a vehicle speed signal with a period of less than 1 second, it calculates the counting result of the clock counter 80b every time the vehicle speed signal falls after the second falling point of the vehicle speed signal. Output as instantaneous vehicle speed. but,
When the vehicle speed signal period becomes 1 second or more, the clock counter 8
0b and register 80c are reset. The vehicle speed signal calculated in this manner is supplied to the oil flow rate decoder 85. Since the oil flow rate decoder 85 is constituted by a ROM in which oil flow characteristics corresponding to vehicle speed as shown in FIG. 3 are written, the oil flow rate decoder 85
reads out a signal representing the oil flow rate control amount corresponding to the vehicle speed at that time, and supplies the signal to the oil flow rate setting circuit BT.

The oil flow characteristics written in the oil flow decoder 85 differ depending on whether the load is small, medium, or small, and also depending on whether the road you are driving on is city, suburban, highway, etc., so it should normally depend on the driving condition. It is necessary to memorize all necessary oil flow characteristics. For example, as shown in the symbols S=1 to 8=5 in FIG.
Type. Normally, it would be necessary to store all the characteristics shown in FIG. 4, but here, only one type of characteristic of 8=3 is stored. As a result, the oil flow rate decoder 85 reads out a signal that changes the oil flow rate control amount corresponding to the instantaneous vehicle speed at that time in accordance with the characteristic shown by 8=3 in FIG. supply

Since the vehicle speed signal is also supplied to the average vehicle speed calculation circuit 81, the vehicle speed counter 81a of the average vehicle speed calculation circuit 81 counts up each time the vehicle speed signal is supplied. And 30
Since the reference signal is supplied from the reference signal generation circuit 88 every second, the register 81c takes in the count value of the vehicle speed counter 81a up to that point every time the reference signal is supplied. Then, the reference signal is sent to the delay circuit 81b for an appropriate time, for example, 1
Terminal R of the vehicle speed counter 81a is delayed by about microseconds.
The vehicle speed counter 81a can be reset completely. When the reset is released, the vehicle speed counter 81B starts counting the vehicle speed signal again. Therefore, register 81c
From there, the counted value of the vehicle speed signal for 30 seconds is sent out as an average vehicle speed signal, and is supplied to the driving condition decoder 84. Similarly, the steering signal output from the steering signal generation circuit 2 is calculated by the average steering amount calculation circuit 82, and the count value of the steering signal every 30 seconds is supplied to the running condition decoder 84 as the average steering signal.

The driving condition decoder 84 decodes whether the vehicle is traveling in an urban area, in the suburbs, or on an expressway, and has characteristics written therein in which the average vehicle speed and average steering amount are used as variables, as shown in FIG. When the average vehicle speed and the average steering amount are supplied, the driving condition decoder 84 reads the driving condition and supplies a signal representing the driving condition to the control pattern decoder 86. In addition, in FIG. 5, area A represents an urban driving area where the average vehicle speed is below a medium level and the area where the value is small has a wide average steering amount distribution, and the higher the average vehicle speed, the smaller the average steering amount distribution. Area B has a medium average vehicle speed, but the average steering amount is distributed in a relatively large value range in the part where the value is small, and the average steering amount distribution range becomes wider as the average vehicle speed increases. It represents an area. Area C
represents a high-speed driving area where the average vehicle speed is large regardless of the average steering amount. In FIG. 5, area A.

M=1, M=2, M=3 written in B and C
is a variable that differs depending on the driving zone used when correcting the oil flow rate, which will be described later.

On the other hand, the load detection circuit 83 is supplied with signals from the heavy load detection circuit 3, the light load detection circuit 4, and the vehicle speed signal generation circuit 1.
A load signal is generated according to the state of each signal, and this load signal is supplied to the control pattern decoder 86 and the intermediate flow rate setting circuit 89. The load detection circuit 83 receives “0” from either the heavy load detection circuit 3 or the light load detection circuit 4.
'' level signal is generated, the signal is inverted by the inverter 83k or 83t and supplied to the AND circuit 83a or 83b, so this signal is supplied to the heavy gravity wanton 83p or 83q every 10 milliseconds and is counted. be done. This count value is determined by the load determination circuit 83h,
The data of the determination result is supplied to the terminal of the register 831. Then, when a signal generated every 10 seconds from the reference signal generation circuit 88 is supplied to the terminal C of the register 83i, the load determination result is taken into the register 831. 1 At this time, the signals sent from the register 83i are designed to have the values shown in Table 3 depending on the load state. Further, since the signal generated every 10 seconds from the reference signal generation circuit 88 is supplied to the heavy load counter 83p and the light load counter 83q via the delay circuit 83r, these color /
The counter is reset every 10 seconds and counts new data.

Table 3 The running condition signal and load signal determined in this manner are supplied to the control pattern decoder 86, and calculations are performed according to the standard of equation (1) shown below, and the control pattern decoder 86 corrects the calculated Signal to oil flow rate setting circuit 87
supply to.

C=M+L...(1) However, the definition of each symbol is as follows.

C: Correction signal M: Running condition signal L: Load signal As a result, the correction signal C takes into account both the running condition and the load state.

In addition to the correction signal C, the oil flow rate setting circuit 8T is supplied with a signal representing the oil flow rate q determined by the characteristic of 8=3 in FIG. 4 read out from the oil flow rate decoder 85 and the vehicle speed. According to the criteria of formula (2),
A control signal for controlling a power steering device (not shown) is sent out.

Q=q+A(C-3) (2) However, the definition of each symbol is as follows.

Q: Control signal q: Signal that controls the oil flow rate read from the reference characteristic A: When each characteristic shown in Fig. 4 is assumed to be at equal intervals, the value representing the interval is Since we have selected 8-3 in the figure, for example, if the running condition is M-1 and the load signal is L = 1, the correction signal is C-2 from equation (1) υ, and the control signal is equation (2). Therefore, Q=q−A. For this reason, 8 in Figure 4
-2 characteristics are selected. Similarly, M=1. If it is L-0, it becomes Q-q-2, and the characteristic S-1 in FIG. 4 is selected. In this way, since the reference characteristics are shifted depending on the operating conditions, power steering that matches all operating conditions can be performed by storing only one type of characteristic in the oil flow decoder 85.

The signal output from the oil flow rate setting circuit 87 is converted into an analog voltage by the D/A converter 5, and this analog voltage is used to drive a solenoid coil having a duty ratio according to the magnitude of the analog voltage. converted into a signal. As a result, the solenoid coil 7 supplies the amount of oil according to the duty ratio to the power steering device (not shown), so that power steering is performed according to the operating conditions.

The above is the normal operation, but the operation when there is a failure in which no output signal is generated from each sensor from the vehicle speed signal generation circuit 1 to the light load detection circuit 4 is as shown in Table 4 below. In Table 4, the ◯ mark indicates a state in which the sensor is normally generating a signal, and the x mark indicates a state in which the sensor is not generating a signal.

The fourth failure mode can be roughly divided into a pattern in which no signal is generated from the vehicle speed sensor and a pattern in which a signal is generated from the vehicle speed sensor. First, the vehicle speed sensor fails and a vehicle speed signal is generated. I will explain the operation when the machine is overloaded.

When the ignition switch (not shown) is turned on, an initial reset is performed, so the load detection circuit 83
falling memory circuit 83j1, 3-second clock counter 89a1 of intermediate flow rate signal generation circuit 89, load change memory circuit 89t
Since each generates a "0" level signal, the oil flow rate setting circuit BT sets the oil flow rate to the fixed flow rate. Since no vehicle speed signal is generated, the one-second timer 83f generates an output signal at the "1" level one second after the ignition switch is turned on. As a result, Punto circuit 89C1 delay circuit 89m, AND circuit 89
Since the 3-second clock signal is supplied to the terminal CU of the 3-second clock counter 89a through the b@, the 3-second clock counter 89a is counted and amplified every 3 seconds. When this count is repeated 5 times, that is, 15 seconds after the ignition switch is turned on, the count value of the 3-second clock counter 89a reaches 15'', so the 3-second clock counter 89a reaches the ``1'' level. It begins to send out signals.

Since this signal sets the terminal 87b of the oil flow rate setting circuit 87 to the "1" level via the OR circuit 89k, the oil flow rate is switched from the final flow rate to the intermediate flow rate.

In this way, when the vehicle speed sensor, load sensor, and steering sensor are all out of order, the oil flow rate is controlled to be a constant flow rate after startup and then to an intermediate flow rate after a predetermined period of time, as shown in the fourth pattern A5.

Next, when the vehicle speed sensor and load sensor are out of order but the steering sensor is normal, a 3 second clock signal generated every 3 seconds is passed through the OR circuit 891 of the intermediate flow rate signal generation circuit 89 to the average steering amount calculation circuit. The signal generated from the steering sensor and processed by the steering signal generation circuit 2 is outputted from the average steering amount calculation circuit 82 every three seconds and compared by the comparison circuit 90. At this time, when the number of pulses generated in 3 seconds is 3 or more, the comparator circuit 90 generates an output signal of "1" level. Therefore, as in periods T1 to T6 in FIG. 6(, ), when the number of steering pulses every 3 seconds shown in () is less than 3, each time the 3-second clock signal shown in (C) is generated, Then, the 3-second clock counter 89a counts up as shown in (d). Therefore, the 3 second clock counter 89a
is counting a value less than 51, the oil flow rate is set to the final cutting flow rate as shown in (,).

When the period T6 begins, the count value of the 3-second clock counter 89a becomes "5", so the oil flow rate is switched from the final flow rate to the intermediate flow rate. During the period T7, four steering pulses are generated in 3 seconds as shown in FIG. As shown in (d), the count value changes from "5" to "4". Therefore, the intermediate flow period is the period T6. Only T7 is used, and the period T8 is switched to the final cutting flow rate.

Thereafter, operations are performed in the same manner, but for a period T10. At T11, four steering pulses are generated every 3 seconds, so
The 3-second clock counter 89a counts down both times. As a result, the count value of the 3-second clock counter becomes less than "5" during the period Tll to T13, and the flow rate is set to the final cutting rate during this period.

Therefore, when the vehicle speed sensor and load sensor are out of order and the steering sensor is normal, the flow rate is set to the final flow rate for a minimum of 15 seconds after the ignition switch is turned on, and thereafter the flow rate is switched to the intermediate flow rate. However, if there are several periods in which three or more steering pulses every 3 seconds occur during these 15 seconds, the cut-off flow rate period can be extended by the period equal to the number of times this phenomenon occurs multiplied by 3 seconds. Then, when the final flow rate period ends and the number of steering pulses every 3 seconds becomes 3 or more even in the intermediate flow period, the oil flow rate is set to the final flow rate again, and 3
If the period in which the number of steering pulses per second is 3 or more continues, the cutoff flow rate period is extended. For this reason, when the vehicle speed sensor and load sensor are out of order and the steering sensor is normal, control is performed in which "the flow rate is set to the final cutoff amount when the steering signal is generated" as shown in pattern A3 of Table 4.

Next, when the vehicle speed sensor and steering sensor are out of order and the load sensor is normal, a signal generated from the sensor is detected by the rise and fall detection circuit 83e, and is supplied to the load change storage circuit 89t via the AND circuit 89f. be remembered. As a result, the oil flow rate is controlled to be [intermediate flow rate when load fluctuation occurs] as shown in pattern A4 in Table 4.

If the vehicle speed sensor is malfunctioning, but the load sensor and steering sensor are normal, they will operate in the same way as described above, but depending on whether a load fluctuation occurs or a steering signal is generated, the operation shown in Table 4 will change. It is determined whether the control is to be performed as in pattern A1 where the flow rate is set to an intermediate flow rate when a load signal is generated, or the flow rate is set to a full cut flow rate when one steering amount is generated as in pattern A2.

The above is the operation when the vehicle is stopped, but if the vehicle speed sensor is malfunctioning, the operation is exactly the same when the vehicle is running as when the vehicle is stopped, and depending on whether each sensor is good or bad, the pattern Alt = A5a in Table 4 is shown. controlled by.

Next, when the vehicle speed sensor is normal, a signal generated from the vehicle speed sensor and processed by the vehicle speed signal generation circuit 1 is output to the falling edge detection circuit 8.
3d, the falling memory circuit 83j outputs “1”.
” level signal is output. As a result, the oil flow rate setting circuit 87 ignores the signal supplied to the terminal 87b and is dominated by the signals supplied to the terminals 87c and 87d.

When the average steering amount calculation circuit 82 generates a vehicle speed signal,
The average steering amount signal is sent out every 30 seconds, and when the steering sensor is out of order, the average steering amount signal is set to represent zero. On the other hand, when the value of the signal representing the average steering amount is zero, the driving condition decoder 84 selects the intermediate mode, i.e., urban, suburban,
The mode is set when driving on suburban roads, which are between expressways. Therefore, when the steering wheel height fails, the "intermediate mode when there is no steering pulse for a certain period of time (30 seconds in this embodiment)" is set, as shown in pattern B3 in Table 4.

Next, when the vehicle speed sensor height steering sensor is normal and the load sensor is out of order, the load detection circuit 83 determines that the load is neither heavy nor light, that is, the load is medium. For this reason, at this time, setting to a medium load state is performed as in turn B2 of Table 4. Furthermore, if both the load sensor and the steering sensor fail, each control is performed independently, so control is performed to "set to medium load state, intermediate mode" as in pattern B4 of Table 4.

FIG. 7 is a circuit diagram when the apparatus shown in FIG. 1 is constructed using a microcomputer. In the figure, the vehicle speed signal generation circuit 1 includes a reed switch 1a, a diode 1b,
Resistors 1C to 1e, NAND circuit 1f.

It is composed of 1g. And reed switch 1
As shown in FIG. 8, a is provided near a disc 1h configured to rotate integrally with the width of the vehicle, and whenever a magnet 11 provided around the disc 1h approaches the reed switch 1a. , reed switch 1& is turned on to generate a vehicle speed signal.

Steering signal generation circuit 2 includes photo interrupter 2 & resistor 2
b to 2e, and NAND circuits 2f and 2g.

The photointerrupter 2a is provided near the slit disk 21 which rotates together with the steering shaft 2h as shown in FIG. 928-(,).
The photointerrupter 2a is turned on every time the slit 2j provided in the slit disk 21 shown in FIG. 1 passes through four parts of the photointerrupter 2a. The heavy load detection circuit 3 includes a photointerrupter 3a and resistors 3b to 3e1.
The light load detection circuit 4 is composed of a photointerrupter 4a, resistors 4b to 4e, and NAND circuits 4f and 4g.

The photointerrupters 3a and 4a are incorporated into a load sensor as shown in FIG. 1 in Figure 10
00 is a wheel, 101 is an axle, 102 is a leaf spring, 103 is a link, 104 is a lever, 105 is a shaft, and 106 is a cylinder. The shaft 105 is rotatably supported by a vehicle body (not shown), and the cylinder 106 rotates together with the shaft 105. One end of the lever 104 is fitted into the shaft 105 so as to rotate together with the shaft 105, and the other end is rotatably supported on the upper end of the link 103. Link 1
The lower end of 03 is fixedly attached to the center of the leaf spring 102,
Therefore, when the load increases and the vehicle height decreases, the link 103 does not change its position, but the shaft 105 rotates and moves downward. Photo interrupter 3a
, 3b is fixed to the vehicle body, and is attached so that the light emitted from the light emitting part is turned on or off depending on whether the light is blocked by the peripheral edge 106a of the cylinder 106 in a non-contact state or passes through the slit 106b. ing.

The D/A conversion circuit 5 includes resistors 5a to 50 and an operational amplifier 5p. The solenoid coil drive circuit 6 is composed of resistors 6a to 6p, capacitors 6q, operational amplifier 6r, diodes 6B, 6t, transistors 5u, H6vs, comparators 6w, 6x, and 6y.The attached circuit 9 includes resistors 9a to 9d, It is composed of switches 9e to 9g, capacitors 9h and 9i, a ceramic oscillator 9j, and a reset circuit 9k. The control circuit 8, which is a microcomputer, is manufactured by Sanyo Electric LM641) 2
It consists of

The device configured in this manner is controlled by a program written in the control circuit 8, as shown in FIG. 11(a).

The operation is performed according to the flowchart shown in (b).

FIG. 11 shows the operation of a program configured to perform the same operations as the apparatus shown in FIG.

In FIG. 11(,), when the initial setting shown in step 200 is performed, the interrupt process shown in FIG. 11(b) is performed every millisecond. This process is performed in a timer (not shown) included in the reference signal generation circuit 88 in FIG.
1 is determined to be [YESJ, the process of setting the vehicle speed flag shown in step 302 to "0", the process of skipping step 302 when step 301 is determined to be "NO", and the process from step 303 to step 308. The processing from the 3 second timer count up to the 10 millisecond signal count up shown in step 309, and the 10 millisecond elapsed time shown in step 309 is [YE
When it is determined that sJ is the load state judgment shown in step 310, and depending on the load state, the process of setting the light load data 31-ta NL plus 1 as new light load data NL shown in steps 311 and 312. and a process in which the value obtained by adding 1 to the heavy load data NH is set as new heavy load data NH, and it is determined whether the vehicle speed flag shown in step 313 is "1" or not [oJ, step 31
When the determination of the existence of load fluctuation shown in step 4 is "YES", the L flag, that is, the load flag is set to 11 as shown in step 315.
”, the process of returning to the step where the interrupt occurred,
Then, after 10 milliseconds have elapsed as shown in step 309, whether the determination of the presence of load fluctuation as shown in step 314 is [oJ] or the determination that the vehicle speed flag is "1" as shown in step 313 is "YE".
The process of returning to the step where the interrupt occurred at "S" is performed sequentially.

On the other hand, in the main routine, when the vehicle speed signal is input as shown in step 201, the falling point of the vehicle speed signal can be determined in step 202, but if it is not the falling point of the vehicle speed signal, the steering signal is input as shown in step 203. is input. If it is determined in step 204 that it is the falling point of the steering signal, then as shown in step 205, the count value N of the steering counter 82a in FIG.
8 is 1 count 32- The door is slammed, and the vehicle speed flag at step 206 is "
1" is made, but if it is determined in step 204 that it is not the falling point of the steering signal, step 20 is made.
4, the vehicle speed flag in step 206 is determined as [1-1]. And step 206 is JYES
If it is determined that 10 seconds have passed as shown in step 207, a determination is made that 10 seconds have passed, and if this determination is l'-YE8J, the first
The load determination circuit 83h shown in the figure generates a load signal as shown in step 208 in accordance with the standards in Table 3 based on the data of the count value NH1 of the heavy load counter 83p and the count value NL of the light load counter 83q. At this time, as shown in Table 3, the value of L is set to "0" in a light load state, "1" in a heavy load state, and "2" in a heavy load state. Then, as shown in step 209, the count value of the heavy load counter 83p and the count value NLO value of the light load counter 83q are
0'' and it is determined in step 209 that 30 seconds have elapsed. However, if it is determined in step 207 that 10 seconds have not elapsed, steps 208 and 209
The process of step 210 can be omitted, and the step 210 determines whether 30 seconds have elapsed directly from step 207.

When it is determined in step 210 that 30 seconds have passed, the driving condition decoder 84 in FIG. Generate M. At this time, as shown in FIG. 5, the value of M is set to 1 when driving on an expressway, M=2 when driving on a general road, and M=3 when driving on a mountain road.

Then, as shown in step 212, the steering counter 82
Assuming that the count value Ns of a and the count value Nv of the vehicle speed counter 81a are 10'', as shown in step 213, after adding the value of the load signal and the value M of the driving condition to obtain the correction value C,
Flow returns to step 201. However, step 21
If it is not determined that 3 () seconds have passed at 0, step 2
11 and 212 are omitted.

On the other hand, if it is determined in step 206 that the vehicle speed flag is not 11, a determination is made in step 214 as to whether the F flag for setting the intermediate flow rate is 1, and if this determination is YES, step As shown in step 215, the oil flow rate setting circuit 87 in FIG. 1 controls the intermediate flow rate, and in the case of 1NO, the oil flow rate setting circuit 87 in FIG. 1 controls the final flow rate as shown in step 216.

Then, in step 217, if 3 seconds have passed, the answer is "YES".
When it is determined that Ns≧ as shown in step 218
Make judgment 3. This process is carried out in the comparator circuit 90.
It is determined whether the number Ns of steering pulses every 3 seconds is greater than 3 or not. If step 218 is determined as JYESJ, F, L as shown in steps 219 and 220
The flag is set to "0", and if the counted value of the 3-second clock counter 89a shown in FIG. 1 is not "10" as shown in step 221, r
The process Nss=N5s-IJ is performed and it is determined that the L flag shown in step 223 is "1". However, if it is determined in step 217 that 3 seconds have passed and the result is NOJ, the processes in steps 218 to 222 are omitted.

In addition, if it is determined in step 218 that "Ns≧3 is 1NO", a determination of NS8''5 shown in step 224 is made, and this step is determined as "NO".
5- After the processing of r N5s=Nss''j is performed as shown in step 225, ?'J is performed again in step 226.
A determination is made that ss=5. And step 226
If it is determined that ``1YES'' is determined, the F flag is set to ``1'' as shown in step 227, and the flow proceeds to step 223. However, if either the processing of N5s=0 shown in step 211 or N5s=5 shown in step 224 is determined to be [YESj], or if rNss=5J shown in step 226 is determined to be 1NOj, the flow will continue at that point. The process then proceeds to step 223.

If the L flag is determined to be rlJ in step 223, the F flag is set to "1" as shown in step 22B, the L flag is set to "0" as shown in step 229, and the flow returns to step 201. However, if it is determined in step 223 that the L flag is not "1", the processes in steps 228 and 229 are omitted.

While repeating steps 201 to 229,
Eventually, in step 202, it is determined that the vehicle speed signal has fallen, so steps 230 to 232 include processing to set the F and L flags to 10, reset the 1-second timer, and set the vehicle speed flag to 1. After the setting process is performed, the count value N of the vehicle speed counter 81a in FIG.
v is counted up by one as shown in step 233. Thereafter, in step 234, the instantaneous vehicle speed V is calculated based on the count value V of the 1 millisecond signal counted in step 307, and in step 235, the count value V of the 1 millisecond signal is set to "0". Thereafter, as shown in step 236, the oil flow rate q is read out from the oil flow rate decoder 85 according to the instantaneous vehicle speed V, and step 2
As shown in 37, this oil flow rate q is corrected according to the standard of equation (2) in accordance with the correction value C depending on the running conditions, and the oil flow rate Q that is suitable for the running conditions at this time is determined. Then, as shown in step 238, control is performed so that the oil flow rate becomes Q.

In this way, the correction signal C is generated from the load signal and the driving mode signal M, and the oil flow rate is corrected by this correction signal C. Therefore, even if only one characteristic is stored in the oil flow decoder 85, this Three types of characteristics can be corrected depending on the load state, and these three types of characteristics can be further corrected three types depending on the driving mode, so as a result, one suitable for the driving conditions can be selected from among nine types of characteristics.

〔Effect of the invention〕

As explained above, when the control device for the power steering device according to the present invention controls the oil flow rate according to the signals supplied from the plurality of running condition sensors, one or more of the running condition sensors When the output signal is no longer generated, the oil flow rate is controlled to the optimal value at that time, so when the driving condition sensor fails, the steering force does not fluctuate drastically like in the past. This has the effect of allowing safe driving.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram of each part showing the operation of the instantaneous vehicle speed calculation circuit 80 in FIG. 1, and FIG. 3 is a graph showing representative characteristics of vehicle speed and oil flow rate. , Fig. 4 is a graph showing the characteristics of the vehicle speed and oil flow rate determined by driving conditions, Fig. 5 is a graph showing the characteristics of the average steering amount distribution with respect to the vehicle speed, and Fig. 6 is a graph showing various parts for explaining the switching state of the oil flow rate. A waveform diagram, FIG. 7 is a diagram showing an example of the device shown in FIG. 1 configured with a microcomputer, FIG. ) is a cross-sectional view of the steering shaft portion with a photo interrupter added to the steering signal generation circuit, FIG. 9(b) is a plan view showing the slit disk, and FIG. 10 is a photo of the heavy load detection circuit and light load detection circuit. A perspective view showing a load sensor configured with an interrupter attached;
FIG. 11 is a flowchart showing the operation of the apparatus shown in FIG. 7. DESCRIPTION OF SYMBOLS 1...Vehicle speed signal generation circuit, 2...Steering signal generation circuit, 3...Heavy load detection circuit, 4...Light load detection circuit, 8...Control circuit, 80. ... Instantaneous vehicle speed calculation circuit, 81 ... Average vehicle speed calculation circuit, 82 ...
Average steering amount calculation circuit, 83...Load detection circuit, 83
a, 83b...G39-1 circuit, 83e...AND circuit, 83d...
Rise detection circuit, 83e... Rise and fall detection circuit, 83f... 1 second timer, 83h... Load judgment circuit, 83i... Register, 84...
Running condition decoder, 85...Oil flow rate decoder,
86...Control pattern decoder, 87...Oil flow rate setting (b) path, 88...Reference signal generation circuit,
89... Intermediate flow rate signal generation circuit, 90... Comparison circuit. Patent applicant: Jidosha Kiki Co., Ltd. Agent: Kazuki Yamakawa (2 people)

Claims (1)

[Claims] In a power steering device control device that controls oil flow rate in response to signals supplied from a plurality of running condition sensors, the oil flow rate is adjusted to that level when one or more running condition sensors no longer generate signals. 1. A control device for a power steering device, comprising a control circuit that sets an optimum value at a certain point in time.