JPS5948266A - Motor controller for power steering gear - Google Patents

Abstract

PURPOSE:To prevent an assisting force from becoming excessively large even at the time of a rapid braking during high-speed running, by controlling a supply power quantity regulating means by a signal from a rapid braking detecting means so that the quantity of electric power supplied to a motor is forcibly reduced to or below a predetermined value. CONSTITUTION:When rapid braking is conducted during high-speed running, signals from a vehicle speed sensor 21 and a brake switch 26 are inputted into an AND circuit 51 provided in a rapid braking detecting circuit 24. Since the circuit 51 causes the output from a Q'-terminal of a flip-flop 50 to become ''L'', an output from an AND circuit A remains to be ''L'' even when a signal from a steering sensor 36 is inputted. The output ''L'' from the circuit A is inverted into ''H'', and is inputted into an AND circuit 37. The circuit 37 supplies a signal PI from an idle signal generating circuit 38 to a power transistor 30 provided in the supply power quantity regulator 19. In accordance with the signal, the transistor 30 supplies a small amount of an electric current I to the motor 18, and the motor 18 is operated in an idling condition. Accordingly, discharge quantity of a pump is restricted, and the assisting force at the time of rapid braking is maintained to be appropriate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor control device for a power steering device, and more particularly to a motor control device for an oil pump device of a power steering device.

Conventional oil pump devices used in power steering devices generally consist of an oil pump driven by an engine and a flow control valve that controls the flow rate of pressurized oil discharged from the oil pump. In order to always obtain the optimum steering force for the power steering device depending on the magnitude of is supplied to the e-war cylinder device, and its sufficient output enables light steering operation.On the other hand, when driving at high speeds with little steering resistance, most of the pressure oil discharged from the oil pump is diverted to oil. The output of the blower cylinder device is reduced by circulating the flow to the suction side of the pump, allowing relatively stable handle operation.

However, as mentioned above, in conventional pump devices, the amount of oil supplied to the power cylinder device is controlled not by controlling the discharge amount of the oil pump, but by controlling the flow rate with a flow rate control valve installed afterwards. Therefore, even if the power cylinder device does not require much pressure oil, the mail pump must always discharge a large amount of pressure oil, and the difference in energy is wasted and the power cylinder device is The disadvantage is that the amount of oil supplied tends to fluctuate under the influence of pressure fluctuations due to operation, making it difficult to obtain a stable operating feel.

Therefore, in the pump device for the power steering device disclosed in Japanese Patent Application Laid-Open No. Sho-33039, the oil pump is driven by an electric motor, and the rotational speed of the electric motor, that is, the rotational speed of the oil pump, is adjusted depending on the vehicle speed. By controlling the amount of oil, only the required amount of oil can be discharged by the oil pump and supplied to the power cylinder, thereby solving the drawbacks such as energy loss in the conventional device.

However, this Unexamined Patent Application Publication No. 1973-! The pump device for the power steering device of No. 5-039 uses an electric motor that is controlled according to the vehicle speed as the drive means for the mail pump, so it can efficiently apply the steering assist force under normal conditions. This allows steering to be performed in the desired condition, but if you apply sudden brakes while driving at high speed and simultaneously perform steering, the steering assist force may become excessive and oversteer may occur, resulting in a dangerous situation. . This is because, although the assist force for steering during sudden braking should be determined according to the driving speed before braking, when the wheels are locked due to sudden braking, the assist force is generally determined by the vehicle speed sensor. The output of the motor suddenly decreases, and the electric motor is operated in the same way as when the station is stationary, and as a result, the oil motor driven by this electric motor is driven by the electric motor. This is because the pressure oil discharged from the pump becomes excessive.

Therefore, in view of the drawbacks of the prior art, the present invention provides a power steering device that can obtain the optimum assist force without excessive steering assist force even when braking suddenly while driving at high speed as described above. The object of the present invention is to provide a motor control device.

The present invention relates to a power cylinder device that assists steering force, an oil pump that generates pressure oil to be supplied to this power cylinder device, an electric motor that drives this oil pump, and an adjustment of the amount of power supplied to this electric motor. a vehicle speed sensor that generates a vehicle speed signal according to the traveling speed of the vehicle; and a vehicle speed sensor that receives the vehicle speed signal and decreases the supply type 1JFt according to an increase in the traveling speed indicated by the vehicle speed signal. In the motor control device of the e-power steering device, which has a control means for controlling the power supply amount adjustment means, the brake is operated in a high speed range state where the traveling speed indicated by the vehicle speed signal is equal to or higher than a reference vehicle speed. sudden braking detection means for detecting the sudden braking, and a reduction in the amount of supplied power that receives the output of the sudden braking detection means and controls the supplied power amount adjusting means to forcibly reduce the amount of supplied power to a predetermined value or less. It is characterized by having means.

In the motor control device for the /F quateering device of the present invention having the above structure, the sudden braking detection means detects that the brake is operated in a high speed range state, and controls the amount of power supplied to the electric motor to a predetermined value. The motor is forced to idle below this value, and the amount of oil discharged from the oil pump is kept at the minimum necessary level or zero, so it is not necessary to apply the brakes while driving at high speed. When steering at the same time, even if the wheels become locked and the output of the vehicle speed sensor becomes 0, the steering assist force will not become excessive due to this and the steering will always be maintained. A good steering smoothing force can be obtained.

Hereinafter, a motor control device for a power steering device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a circuit in which the motor control circuit of the present invention is incorporated.
FIG. 2 is a system diagram showing an example of a power steering device.

The power steering device P is equipped with rank and pinion type steering as manual steering. In the figure, reference numeral 1 denotes a steering wheel, and a steering shaft 2 rotated by the steering wheel 1 is connected to a pinion 5 via joints 3 and 4. The vinyl membrane 5 is meshed with a rack 6, and tyron doors a and 7b are connected to both ends of the rack 6 at one end. The other end of each tyron door a, 7b is connected to a knuckle arm 9a, 9b rotatably supported around a shaft 8a, sb, respectively. With the above structure, when the steering wheel 1 is steered and the rotation of the steering shaft 2 is transmitted to the rack 6 via the pinion 5, the rack 6 moves in the left and right direction, and the knuckle arm 9a is moved via the tie rods 7a and 7b. , 9b to give a steering angle to the steering wheels 10a and iQb, which are generally front wheels.

The power steering device P has a power cylinder device 11 that performs a power assist function, and the power cylinder device 11 includes pressure chambers 11a and 11b formed by a piston 11c. This ring device 11
The rack 6 passes through the inside, and the piston 11c is fixed to the rack 6. Therefore, the piston 711c includes this rack 6, the tie rods 7a and 7b, and
and the steering wheel 10a via the knuckle arms 9a, 9b.
, 10b.

Each of the pressure chambers 11a and 11b is a hydraulic passage 12a.

It is connected to the control pulp 13 via 12b. This control pulp 13 is connected to an oil pump 7'14 for supplying pressure oil to the cylinder device 11 via a discharge passage 15 and a return passage 11 having a reservoir 16 disposed therebetween. The control valve 13 has been conventionally used in this type of /f power steering device, and it connects the discharge passage 15 and return passage 17 of the oil pump 14 to the hydraulic passage 12a, the hydraulic passage 12a, and the return passage 17, respectively, according to the steering direction. and 12b, or conversely, the hydraulic system is switched to connect to 12b and 12a. For example, when the rack 6 is steered to move to the right in the figure, the discharge passage 15 is connected to the hydraulic passage 12.
b, the return passages 17 are respectively connected to the hydraulic passages 12a, and as a result, the pressure chambers 11b of the power cylinder device 11
Pressure oil is supplied to the piston 11c, and this pressure oil acts on the left side surface of the piston 11c in the drawing, thereby assisting the rightward movement of the rack 6. Furthermore, when the steering shaft 2 is not being rotated, the control pulp valve 13 allows direct communication between the discharge passage 15 and the return passage: l-7, so as not to send pressure oil to the power cylinder 11. .

The mail pump 7° 14 is driven by an electric motor 18, and the electric motor 18 is connected to a power supply regulator 19 having a power transistor, and is supplied from the power supply regulator 19. A control circuit 20 is connected to the power supply regulator 19.
Connected to this control circuit 20 is a vehicle speed sensor 21 that detects vehicle speed and generates a vehicle speed signal SI indicating this vehicle speed. The control circuit 20 receives the vehicle speed signal S+ from the vehicle speed sensor 21 and outputs a control signal S2 having a value inversely proportional to the magnitude of the vehicle speed signal SL to the power supply amount regulator 19. The power supply regulator 19 supplies the motor 18 with an amount of power W proportional to the control signal S2. That is, the supply power amount regulator 19 supplies a larger power W to the motor 18 as the vehicle speed decreases.
The amount of pressure oil discharged from 4 is increased to enable light steering at low speeds where steering resistance is high or when the vehicle is stopped.

However, with a power steering device that only has the configuration described above, it is difficult to turn the steering wheel at relatively long speeds, such as when changing directions when entering a garage, at a U-Turf, or when waiting at a traffic light, or when stationary while stopped. When the full steering condition is maintained, the pressure oil discharged from the oil pump 14 continues to be supplied to the power cylinder device, and the pressure oil is continuously supplied to the power cylinder device 15 and the hydraulic path 12a and 12b between the power cylinder device 11 and the oil pump 14. pressure becomes abnormally high,
As a result, the electric motor 18 that drives the oil pump f14 must be operated for a long time in an overloaded state.

Therefore, in the motor control device of this embodiment, the electric motor 1
A supply power reduction circuit 22 is provided which forcibly reduces the power supplied to the motor 18 when the electric motor 8 becomes overloaded, thereby maintaining the safety of the electric motor 18 and the like. This power supply reduction circuit 22 includes a power detector 23 that detects the power W supplied to the motor 18 from the regulator 19.
When the power W detected by the power detector 23 is larger than the reference power indicating an overload of the motor 18, it outputs a signal S3 to stop the operation of the control circuit 2o, and outputs a signal S3 to stop the operation of the control circuit 2o. Control signal s of constant value
4 is supplied to the power supply amount regulator 19. Therefore, the power supply regulator 19 supplies a relatively small constant power to the electric motor 18 to put the motor 18 in an idling state, thereby protecting the motor 18 and the like.

A power steering device with only the configuration described above works well when the vehicle is in normal driving condition and when the vehicle is stationary while the vehicle is stopped. When the wheels are locked by the brakes, the vehicle speed sensor 2
1 becomes 0, the power supply regulator 19 sends a large amount of power to the motor 18, and as a result, the oil pump f14
Since the pump discharges a large amount of pressure oil and supplies it to the power cylinder device 11, the assist force by the power cylinder device 11 becomes excessive.

Therefore, in the motor control device of the present invention, a circuit for forcibly reducing the power supplied to the electric motor 18 is provided in order to ensure safe steering even during sudden braking as described above. That is, the sudden braking detection circuit 24 is connected to the power supply amount reduction circuit 22,
A comparator 25 and a brake switch 26 are connected to the sudden braking detection circuit 24. The vehicle speed sensor 21 is connected to one input terminal of the comparator 24, and the constant voltage generation circuit 27 is connected to the other input terminal.

This constant voltage generator 27 generates a reference voltage Vref indicating a predetermined high vehicle speed region. The comparator 25 compares this reference voltage Vref with the vehicle speed signal SI, and when the vehicle speed signal SI is thicker than the reference voltage Vref, that is, when the vehicle speed indicated by this vehicle speed signal S1 is in a high vehicle speed region, the vehicle speed is high. Outputs a signal S.

The sudden braking detection circuit 24 receives the high vehicle speed signal sa from the comparator 25.
When the brake switch 25 receives a brake signal S6 from the brake switch 25, it outputs a sudden braking signal S7 indicating that it is in a sudden braking state. The power supply amount reduction circuit 22 is
When receiving the sudden braking signal S from the sudden braking detection circuit 24,
Similarly to the above-mentioned shutdown, a signal S3 for stopping the operation of the control circuit 20 is output, and a constant control signal S4 having a relatively small value is supplied to the power supply amount regulator 19. Therefore, the power supply amount regulator 19 controls the electric motor 18
A relatively small constant electric power is supplied to the motor 18 to put it in an idling state, and the amount of oil discharged from the oil ponzo 14 is limited, thereby limiting the assist force by the power cylinder device 11 to a constant value. .

Next, a specific example of an electric control system used in the motor control device described above will be explained with reference to the first part.

The power supply regulator 19 that adjusts the power W supplied to the 1E motor 18 includes a power transistor 30 and a protection circuit 30a connected in parallel to the power transistor 3o to protect it. . ) The base of the f-two transistor 30 is connected to the output terminal of an AND circuit 31, and one input terminal of the AND circuit 31 is connected to the output terminal of a comparator 32. A triangular wave generation circuit 33 is connected to one input terminal of the comparator 32, and a vehicle speed-voltage conversion circuit 34 is connected to the other input terminal. This vehicle speed-voltage conversion circuit 34 is connected to the vehicle speed sensor 21, receives a time series signal indicating the vehicle speed from the vehicle speed sensor 21, and generates a voltage SI that decreases as the vehicle speed increases. The comparator 32 includes a triangular wave generation circuit 3
The triangular wave from 3 is converted into the voltage S from the vehicle speed-voltage conversion circuit 34.
1, a pulse signal ps is generated when the voltage from the circuit 34 is high. The pulse width of this signal Ps becomes smaller as the vehicle speed increases.

An output to the AND circuit is connected to the other input terminal of the AND circuit 31, and a steering timer 35 is connected to one input terminal to the AND circuit. The steering timer 35 includes a transistor 35a, a time constant circuit 35b, and a comparator 35c. L1 to the pace of the transistor 35a of the steering timer 35
A steering sensor 36 is connected that detects a steering operation of the steering wheel 1 and generates a current in accordance with the steering operation. The steering timer 35 outputs a pulse PL whose pulse width is proportional to the time interval during which the current is applied to the pace of the transistor 35a. When the vehicle is in a normal driving state, this signal PL passes through the AND circuit and is input to the other input terminal of the AND circuit 31, and the AND circuit 31
The Noculus signal PS from the comparator 32 is passed through by the width of the input Noyals, and is applied to the pace of the word transistor 30.・The drawer transistor 30 is connected to this ・
A current 1f is applied to the electric motor 18 in proportion to the signal Ps:
and rotates the motor 18 in proportion to the current 1.

The oil pump 14 is operated by the rotation of the motor 18 to supply pressure oil to the lower cylinder device 11, thereby obtaining a steering assist force corresponding to the vehicle speed when steering the steering wheel 1.

The protection circuit 30a includes a coil 30b and a contact 30.
The coil 31b is connected to the power detector 23. The detection of the power from the regulator 19 is based on the current 1 if the voltage is constant.
Therefore, the power detector 23 is constituted by a current detector in this embodiment. Therefore, the power detector 23 will be referred to as the current detector 23 hereinafter. The current detector 23 has a transistor switch 23a connected to the coil 30b, and the transistor switch 23 is connected to the base end of the transistor switch 23a.
The output terminal of an AND circuit 23b that supplies a signal for turning on and off a is connected. One input terminal of this AND circuit 23b is connected to the current 1 supplied to the motor 18 from the power supply amount regulator 19.
A first current detection element 23c is connected which outputs an H1 signal when the allowable current value 1o of 0 is greater than, for example, 23A. Still, the current 1 is connected to the other input terminal of the AND circuit 23b at the allowable current value 1max of the motor 18 and the circuit components of the motor 18, for example '75.
A, a first current detection element 23c is connected which outputs an H1 signal when the current is smaller than A. Therefore, AND circuit 23
When the current 1 is smaller than the allowable current value of the power transistor 30, an LO multiplied signal is output to turn the transistor switch 23'aeOFF, and power is supplied to the motor 18 via the mother power trannosta 30. However, the above current 1 is equal to the allowable current value to of the transistor (+-)
(,25A) or more and less than the allowable current value of the circuit element 1max C'73A), the AND circuit 23b outputs a Hi-fold signal and the transistor switch 23
Turn a on. When the transistor switch 23a is turned on in this way, the coil 30 of the protection circuit 30
b is energized and becomes excited, contact 30C is connected, and this protection circuit 3 mainly supplies current to the motor 18.
This is done via 0a.

When the vehicle speed is O or due to the protection circuit 3Da explained above,
When the contactor 30c that protects the power transistor 30 is closed, the current 1 continues to be supplied to the motor 18. Therefore, since the motor 18 continues to rotate, the oil pump 14 continues to supply pressure oil to the power 7 cylinder device 11.

Then, as mentioned before, the pressure in the discharge passage 15 and the hydraulic passage 12a or 12b between the oil pump 14 and the power cylinder device 11 becomes abnormally high, and as a result, the electric pressure that drives the oil pump 14 becomes abnormally high. This results in the motor 18 being operated in an overloaded state. Therefore, in the motor control device of this embodiment, the load on the electric motor 18 increases, and the power supply amount regulator 19
The current 1 supplied to
When it changes to , the output of the AND circuit 23b becomes Low,
As a result, the transistor 23 a f:'OFF
As a state, the protection circuit 30a is turned off. In this state, in order to prevent excessive current from flowing through the power transistor 30, a supplied power amount reduction circuit 22 is provided. This power supply amount reduction circuit 22 has an AND circuit 37 whose output terminal is connected to the pace of the )9W rannosk 30 . An idle signal generator 38 is connected to one input terminal of the AND circuit 37, and the idle signal generator 38 generates an idle signal P1. occurs. The output of the inverter 39 and the AND circuit A is connected to the other input terminal of the AND circuit 37. The AND circuit A receives the output of the steering timer 35 as an input, and when the output of the steering timer 35 is Low, the inverter 39 inputs the other input terminal of the AND circuit 31 to a high level.
1 signal and supplies the idle signal PI to the power transistor 30. Therefore, when the output of the steering timer 35 is Hl, the Noyawer Tranostar 30 is supplied with the pulse signal Ps from the comparator 32 via the AND circuit 31, and on the other hand, when the output of the steering timer 35 is Low, An idle signal PI from an idle signal generator 38 is supplied via an AND circuit 37, and a current l having a value corresponding to each signal PsXP/ is supplied.
is supplied to the motor 18.

The trannostar 35a of the steering timer 35 is grounded via a transistor switch 40 at its emitter end. The base of this L-lannostar switch 400 is connected to the Q terminal of the flip-flop 41, and the S terminal of this flip-flop 041 is connected to the current detection element 23 of the current detector 23 via an inverter 42.
The output terminal of d is connected. Therefore, as described above, when the load on the electric motor 18 increases and the output of the λ-th current detection element 23d changes from Hl to Low, the S terminal of the flip-flop 41 receives the H1 signal, that is, the signal "/" is applied, and as a result, the Q terminal enters the H1 state, that is, outputs the signal "/".

In this way, when the Q terminal of the flip-flop 41 is in the H1 state, the transistor switch 40 is turned on, the trannostar 35a is grounded, and the comparator 35C
In other words, the output of the steering timer 35 is forced to Lo.
It is considered as w. As a result, the supply of the pulse signal Ps to the P word lanoster 30 via the AND circuit 31 is cut off. On the other hand, the output signal PL in the Low state from the steering timer 35 is inverted to Hl by the inverter 39 and input to the AND circuit 37. As a result, the AND circuit 37
supplies the idle signal PI from the idle signal generator 38 to the power transistor 30. The power transistor 30 generates a small current I in response to this idle signal P.
is supplied to the motor 18, the motor 18 is operated in an idle state, and the amount of oil discharged from the cylinder 7'14 is limited.
Protect 2b etc.

Note that the steering sensor 36 is also connected to the R terminal of the flip-flop 41, and supplies a pulse generated during the next steering to the R terminal to output the flip-flop f41.
I'm trying to reset it.

According to the electric control system used in the motor control device configured as described above, it is possible to perform steering during normal operation of the vehicle or to stop the vehicle in good condition. In the case of steering, there is a possibility that the wheels may be locked due to sudden braking, and in the locked state, the vehicle speed detected by the vehicle speed sensor 21 is substantially 0, so that the /
Since the F pulse signal Ps is of high duty, the current I supplied from the power supply amount regulator 19 to the motor 18 becomes a high value, and there is a possibility that the steering assist force becomes excessive.

Therefore, in the motor control circuit of this embodiment, in order to ensure safe steering even during sudden braking, the supply current 1 to the electric motor 18 is forcibly reduced. An idle signal generator 38, an AND circuit 37, A, etc., which are part of the power supply amount reduction circuit 22, are used. A flip-flop 50 is connected to the other input terminal of the AND circuit A at the same terminal. At the S terminal of this flip-flop 50,
An AND circuit 51 is connected at its output end. One input terminal of this AND circuit 51 is connected to a comparator 25 which outputs a high vehicle speed signal S5 when the vehicle speed is in a high vehicle speed range. A vehicle speed sensor 21 and a constant voltage generating circuit 27 are connected to the input terminals of each of the comparators 250, respectively.

In this embodiment, the vehicle speed sensor 21 is connected to one input terminal of the comparator 25 via a vehicle speed-voltage conversion circuit 34. Therefore, when the vehicle speed exceeds a predetermined speed determined by the input voltage from the constant voltage generating circuit 27, the comparator 25 generates an output at the Hl level. The other input end of the AND circuit 51 is connected to a brake switch 26 that outputs a brake signal S6 when the brake is activated.

In the above configuration, when the brake is suddenly pressed during high-speed driving, the high vehicle speed signal S5 and the brake signal S6 are manually input to the Ω input terminals of the AND circuit 51. At this time, the AND circuit 51 outputs the H1 signal, the today 1 signal is supplied to the S terminal of the flip-flop 50, and a Low signal is generated at the Q terminal of the flip-flop 50.

If this condition occurs during steering, or if steering is performed under this condition, AND circuit A will
Although it receives the pulse signal PL from the steering timer 35, since the signal from the flip-flop 50 becomes Low, it outputs a Low signal. This flip flop 5
The Low signal from 0 is inverted to High by the inverter 39 and input to the AND circuit 37, and as a result, the AND circuit 37 supplies the idle signal P from the idle signal generator 38 to the power transistor 30. The power transistor 30 supplies a small current 1 to the motor 18 in response to the idle signal PI to operate the motor 18 in an idle state and limit the amount of oil discharged from the pump 14.
This maintains the appropriate steering assist force during sudden braking, ensuring steering stability.

At this time, since one input terminal of the AND circuit 31 receives the Low signal from the AND circuit A, the pulse signal from the comparator 32 is not passed through.

Note that even after the brake is released and the brake switch 26 does not generate the brake signal S6, it takes some time for the wheels to return to their original state from the locked state, so the above control is performed for this time interval. It is desirable to continue
For this reason, the brake switch 26 and the flip flop 50
It is desirable to connect a one-shot multi-pipe rake 52 as shown between the R terminals. This one-shot multi-pipe rake 52 is connected to the brake switch 26
A reset signal SR is supplied to the R terminal of the flip 70 and the nozzle 50 after a certain period of time T has elapsed from the time when the signal changes from ON to 0FFK, thereby causing the e-word run source 30 to
Even after the brake is released, it is controlled by the idle signal PI for the above-mentioned time T, and the supply current 1 is maintained in a reduced state.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a power steering device in which the motor control device of the present invention is incorporated, and FIG.
FIG. 2 is a circuit diagram of an electrical control system used in a motor control device according to an embodiment of the present invention. P... Power steering device, 14... Male pump, 18... Electric motor, 19... Supply power amount regulator, 22... Supply power amount reduction circuit, 24... Sudden braking detection circuit . Patent applicant: Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] A cylinder device that assists the steering force, an oil pump that generates pressure oil to be supplied to the cylinder device, an electric motor that drives this oil pump, and adjusts the amount of power supplied to this electric motor. a supply power amount adjusting means, a vehicle speed sensor that generates a vehicle speed signal according to the traveling speed of the vehicle, and a vehicle speed sensor that receives the vehicle speed signal and reduces the supplied power amount in accordance with an increase in the traveling speed indicated by the vehicle speed signal. In a motor control device for a power steering device having a control means for controlling an amount adjusting means, there is provided a motor control device for detecting that the brake is operated in a high speed range state where the traveling speed indicated by the vehicle speed signal is equal to or higher than a reference vehicle speed. A power steering device comprising a braking detection means, and a power supply amount reducing means that receives the output of the sudden braking detection means and controls the power supply amount adjusting means to forcibly reduce the power supply amount to a predetermined value or less. motor control device.