JP4972965B2 - Power steering device - Google Patents

Description

The present invention provides a detection signal from a dedicated or shared detector to an input terminal pulled up or pulled down through a resistor, and drives and controls a steering assisting electric motor or hydraulic actuator based on the given detection signal. it relates to Rupa word steering system.

  Recently, hydraulic power steering devices that supply hydraulic oil from an oil pump to a power cylinder coupled to a steering mechanism of a vehicle and generate a steering assist force from the power cylinder have become widespread. In such a power steering apparatus, in order to obtain an optimum steering assist force, the command rotational speed to the electric motor is determined according to a motor rotational speed map determined by the steering speed and the vehicle speed (vehicle speed).

The steering speed is obtained by counting the number of pulse (row) signals per predetermined time from a steering angle sensor having a rotary encoder that rotates together with the steering wheel (steering member, steering wheel).
In a power steering device, the input voltage of the pulse signal from the steering angle sensor to the electronic control unit is stabilized, and the input terminal of the electronic control unit to which the pulse signal is input is connected to a resistor in order to prevent the influence of electromagnetic noise. Pulled up by.

Patent Document 1 describes an on-chip pull-up circuit that can be selectively enabled / disabled.
Patent Document 2 describes a power steering device that determines an instruction rotational speed for an electric motor according to a motor rotational speed map determined by a steering speed and a vehicle speed (vehicle speed).
Japanese Patent Laid-Open No. 5-259876 JP 2005-7951 A

  In the power steering apparatus described above, the detection signal from the steering angle sensor is also used other than the electronic control unit of the power steering apparatus (for example, ABS (Anti-lock Brake System), SCS (Stability Control) System) etc.) and may be given to other electronic control units. In such a case, there is a problem that it is necessary to replace the resistor pulling up the input terminal of the detection signal.

For example, when the detection signal from the steering angle sensor is used only for the electronic control unit of the power steering apparatus, the pull-up resistance is appropriately about 1 kΩ. However, when it is used other than the electronic control unit of the power steering apparatus, the pull-up resistor needs to be about 100 kΩ so as not to affect the level of the detection signal to the other electronic control unit.
The above-described problem also occurs in a power steering apparatus that is a type that assists steering by an electric motor.

The present invention has been made in view of the circumstances as described above, even if the need to change the resistance value that the input terminal of the control device detection signal is input to pull-up or pull-down there, resistance An object of the present invention is to provide a power steering device that can easily change the resistance value without replacing the power.

The power steering device according to the first aspect of the invention includes an electric motor or hydraulic actuator for assisting steering, and a detection signal from a dedicated or shared detector is given to an input terminal pulled up or pulled down through a first resistor, In a power steering apparatus that drives and controls the electric motor or hydraulic actuator based on a given detection signal, one or a plurality of second resistors that pull up or pull down the input terminal, and the second resistor is energized or de-energized One or a plurality of switching elements to be brought into a state and an external setting are accepted , and the detector is shared with other devices depending on the type of vehicle to be mounted and when the detector is occupied According to circumstances, it comprises setting means for setting on / off of the switching element.

A power steering apparatus according to a second aspect of the present invention further includes a switching element that causes the first resistor to be in an energized state or a non-energized state, and a setting unit that receives an external setting and sets the on / off state of the switching element. It is characterized by that.

In a power steering apparatus according to a third aspect of the present invention, the setting means includes a nonvolatile memory that stores the setting by communication from outside, and the switching element is turned on / off according to the setting stored in the nonvolatile memory. It is characterized by being configured to set.

In a power steering device according to a fourth aspect of the invention, the detector is a steering angle detector that detects a steering angle of a steering member.

According to the power steering apparatus of the first invention, the one or more second resistors pull up or pull down the input terminal, and the one or more switching elements cause the second resistor to be in the energized state or the non-energized state. Since the setting means accepts the setting from the outside and sets on / off of the switching element, even when it is necessary to change the resistance value pulling up or pulling down the input terminal to which the detection signal is input, A power steering device that can easily change the resistance value without exchanging the resistance can be realized.

According to the power steering device of the second aspect of the invention, the switching element causes the first resistor to be in the energized state or the non-energized state, and the setting unit accepts an external setting and sets the switching element on / off. Even if it is necessary to change the resistance value that pulls up or pulls down the input terminal to which the detection signal is input, the power steering can change the resistance value more easily without changing the resistance. An apparatus can be realized.

According to the power steering device of the third invention, the setting means stores the setting by communication from the outside in the nonvolatile memory, and sets the switching element on / off according to the setting stored in the nonvolatile memory. Therefore, even if it is necessary to change the resistance value that pulls up or pulls down the input terminal to which the detection signal is input, the resistance value can be easily set without replacing the resistor or adding parts. A power steering device that can be changed can be realized.

According to the power steering device of the fourth aspect of the invention, the detector that is occupied or shared by the control device is a steering angle detector that detects the steering angle of the steering member, so the input terminal of the control device to which the detection signal is input Even when it is necessary to change the resistance value that is pulling up or pulling down the power steering device, it is possible to realize a power steering device that can easily change the resistance value without replacing the resistance.

Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.
FIG. 1 is an explanatory view schematically showing a main part configuration of an embodiment of a power steering apparatus according to the present invention. This power steering device assists steering in a steering mechanism 1 of a vehicle, and a steering shaft 3 is connected to a steering wheel 2. A pinion 4 is attached to the tip of the steering shaft 3, and the pinion 4 meshes with a rack shaft 5 that extends in the vehicle width direction. A front wheel tire 7 (the other is not shown) is attached to the rack shaft 5 via a tie rod 6.

The rack shaft 5 is also connected to a piston 11 of a power cylinder (hydraulic actuator) 10, and the power cylinder 10 includes a pair of cylinder chambers 10 a and 10 b formed by the piston 11. A hydraulic control valve 13 is connected to the cylinder chambers 10a and 10b through oil supply paths 12a and 12b indicated by broken lines, respectively.
The hydraulic control valve 13 is connected in the middle of an oil circulation path 14 indicated by a broken line, and the hydraulic oil stored in the reservoir tank 15 is pumped out by the oil pump 16 and pumped out. After the hydraulic oil is discharged from the oil pump 16, it is configured to return to the reservoir tank 15 again.
When the oil pump 16 is driven by the electric motor M, the hydraulic oil circulates through the oil circulation path 14, and when it is not driven, the circulation of the hydraulic oil is stopped.

  The opening of the hydraulic control valve 13 changes according to the direction and magnitude of the torque applied to the steering shaft 3, thereby changing the supply state of hydraulic oil to the power cylinder 10. When hydraulic oil is supplied to any cylinder chamber of the power cylinder 10, the piston 11 moves in any direction along the vehicle width direction, thereby generating a steering force and moving the rack shaft 5. Assisted.

The vehicle speed sensor 18 detects the rotational speed of the rotor of the front wheel tire 7, and detects a magnetic metal piece fixed to the rotor, an optical sensor that optically detects a hole provided in the rotor, or the like. Can be used. A vehicle speed signal V that is a detection signal of the vehicle speed sensor 18 is given to the electronic control unit 35.
The steering shaft 3 is provided with a steering angle sensor (steering angle detector) 8 having a rotary encoder for detecting the steering angle of the steering wheel 2, and a pulse signal S of the rotary encoder is transmitted from an electronic control unit (control device). ) 35.

A rotation speed sensor 17 that detects the rotation speed (number of rotations) of the electric motor M is attached to the electric motor M, and the rotation speed Vm detected by the rotation speed sensor 17 is given to the electronic control unit 35.
The electronic control unit 35 determines an instruction rotational speed based on the given pulse signal S and vehicle speed signal V, and drives the electric motor M based on a deviation between the instruction rotational speed and the rotational speed detected by the rotational speed sensor 17. The circuit 19 is feedback controlled to drive the electric motor M, thereby driving the oil pump 16.

  In the power steering device having such a configuration, when the steering wheel 2 is operated and the rotational force is transmitted to the steering shaft 3, the pinion 4 at the tip thereof is rotated, whereby the rack shaft 5 is Move in the direction. As a result, the amount of movement of the rack shaft 5 is transmitted to the tie rod 6, and the direction of the front tire 7 changes. The power cylinder 10 generates an auxiliary force to be applied to the rack shaft 5 when the rack shaft 5 moves in the vehicle width direction.

  FIG. 2 is a block diagram illustrating a configuration example of the electronic control unit 35, the drive circuit 19, the electric motor M, and the rotation speed sensor 17 described above. In the electronic control unit 35, the steering speed calculation unit 24 is given a pulse (sequence) signal S from the steering angle sensor 8 having a rotary encoder, and calculates the steering speed based on the number of given pulse signals S per predetermined time. Then, the steering speed signal Vθ is given to the motor rotation speed map 20. A vehicle speed signal V from the vehicle speed sensor 18 is given to the motor rotation speed map 20.

The input terminal to which the pulse signal S of the steering speed calculation unit 24 is given is pulled up to a 5V power source by a resistor R1, and a PNP transistor Tr1 (switching element) having an emitter connected to the 5V power source and a resistor R2 are connected to the resistor R1. Are connected in parallel.
A resistor R3 is connected between the emitter and base of the transistor Tr1, and the base of the transistor Tr1 is connected to the control unit (setting means) 25 through the resistor R4.
The control unit 25 is connected to an interface circuit 26 for communicating with the outside of the electronic control unit 35 via CAN (Controller Area Network) or K-LINE, and turns on or off the transistor Tr1 depending on the contents set by communication with the outside. Turn off.

The motor rotation speed map 20 records a reference map that defines the relationship between the steering speed, the vehicle speed, and the motor rotation speed. According to the given steering speed signal Vθ and the vehicle speed signal V, the command rotation to the electric motor M is recorded. The speed is output and given to the deviation calculator 21.
The rotation speed detected by the rotation speed sensor 17 of the electric motor M is given to the deviation calculation unit 21, and the deviation calculation unit 21 calculates the deviation by subtracting the rotation speed from the command rotation speed and gives it to the PI control unit 22. .

The PI control unit 22 calculates a control signal for performing PI control based on the given deviation, and provides it to the PWM circuit 23.
The PWM circuit 23 outputs a pulse signal having a pulse width corresponding to the given control signal, turns on / off the drive circuit 19, and drives the electric motor M.
The motor rotation speed map 20, the deviation calculation unit 21, the PI control unit 22, the steering speed calculation unit 24, and the control unit 25 described above are realized by a microcomputer and an EEPROM (Electrically-Erasable Programmable ROM, nonvolatile memory).

  FIG. 3 is a block diagram showing a connection example of the electronic control unit 35 and the steering angle sensor 8 illustrating the microcomputer 34 described above. The steering angle sensor 8 gives an on / off signal from a built-in rotary encoder to the base of the NPN transistor Tr2. The emitter of the transistor Tr2 is grounded through the resistor R6, and the collector is connected to the input terminal of the A / D converter 30 built in the microcomputer 34 (corresponding to the input terminal of the steering speed calculation unit 24 (FIG. 2)). ing.

The microcomputer 34 performs operations of the motor rotation speed map 20, the deviation calculation unit 21, the PI control unit 22, the steering speed calculation unit 24, and the control unit 25 by the main software SW. An EEPROM (setting means) 28 is externally attached.
The base of the transistor Tr1 is connected to the I / O port 29 (corresponding to the output terminal of the control unit 25 (FIG. 2)) of the microcomputer 34 through the resistor R4.

A vehicle speed signal V from the vehicle speed sensor 18 (FIG. 1) is given to an input terminal (corresponding to an input terminal of the motor rotation speed map 20 (FIG. 2)) of the A / D converter 31 built in the microcomputer 34.
A rotation speed signal Vm from the rotation speed sensor 17 of the electric motor M is given to an input terminal (corresponding to an input terminal of the deviation calculation unit 21 (FIG. 2)) of the A / D converter 33 built in the microcomputer 34.

An output terminal (corresponding to an output terminal of the PI control unit 22 (FIG. 2)) of the D / A converter 32 built in the microcomputer 34 is connected to an input terminal of the PWM circuit 23.
The resistor R1 is, for example, 100 kΩ, and the resistor R2 is, for example, 1 kΩ. Other configurations are the same as those of the electronic control unit 35 shown in FIG.

In the electronic control unit 35 having such a configuration, the inspection communication tool 27 is connected to the interface circuit 26 when being incorporated into the vehicle, and a pull-up resistance value is set according to the type of the vehicle. From the inspection communication tool 27, “0” or “1” corresponding to the type of vehicle is written in the pull-up selection information bit in the EEPROM 28.
For example, when “0” is set in the pull-up selection information bit, the microcomputer 34 turns off Tr1 by the OFF signal from the I / O port 29, and “1” is set in the pull-up selection information bit. If Tr1 is ON, Tr1 is turned ON by an ON signal from the I / O port 29.
When Tr1 is off, the pull-up resistance value is 100 kΩ, and when Tr1 is on, the pull-up resistance value is 1 kΩ.

  As described above, in the vehicle type in which the detection signal S from the steering angle sensor 8 is used only for the electronic control unit 35, the vehicle type in which the pull-up resistance value is about 1 kΩ and the detection signal S is used for other than the electronic control unit 35. Then, the pull-up resistance value can be set to about 100 kΩ. Thereby, in the vehicle model in which the detection signal S is used only for the electronic control unit 35, the detection signal S can be maintained at an appropriate level. In the vehicle model in which the detection signal S is used in addition to the electronic control unit 35, other electronic The level of the detection signal to the control unit can be prevented from being affected.

Similar to the transistor Tr1, a transistor for energizing / de-energizing the resistor R1 may be provided so that the pull-up resistance value can be set in four ways. Further, it is possible to further provide a pull-up resistor and a transistor for energizing / de-energizing the resistor. Further, the pull-down resistor can be the same as the pull-up resistor described above.
In the above-described embodiment, the hydraulic power steering apparatus is described. However, the same can be applied to a power steering apparatus that assists steering by an electric motor.

In engaging Rupa word steering apparatus of the present invention, avoided in the manufacturer, since the selection process a pull-up resistor or pull-down resistor, it is possible to avoid the model number increased component suppliers, the occurrence of production management costs associated with model number increase can do. Further, when a flash microcomputer or the like is used, the cost of a high part is increased. However, the power steering apparatus conventionally uses an EEPROM (nonvolatile memory) for storing a fail code. In the present invention, this EEPROM is used. The vehicle manufacturer can cope with various vehicle types and options only by changing the software.
The present invention can be widely applied to control devices other than the control device of the power steering device and other systems that require sensors when the interface circuit is of an open collector type. is there.

It is explanatory drawing which shows typically the principal part structure of embodiment of the power steering device which concerns on this invention. It is a block diagram which shows the structural example of an electronic control unit, a drive circuit, an electric motor, and a rotational speed sensor. It is a block diagram which shows the example of a connection of the electronic control unit which illustrated the microcomputer, and a steering angle sensor.

Explanation of symbols

  1 Steering mechanism, 2 Steering wheel, 3 Steering shaft, 4 Pinion, 5 Rack shaft, 8 Steering angle sensor (detector), 10 Power cylinder, 11 Piston, 13 Hydraulic control valve, 16 Oil pump, 19 Drive circuit, 20 Motor Rotational speed map, 24 Steering speed calculation section, 25 Control section (setting means), 26 Interface circuit, 27 Communication tool for inspection, 28 EEPROM (setting means, nonvolatile memory), 29 I / O port, 34 Microcomputer, 35 Electronic control unit (control device), M electric motor, R1 to R6 resistors, Tr1 transistor (switching element), Tr2 transistor.

Claims (4)

An electric motor or hydraulic actuator for assisting steering is provided, and a detection signal from a dedicated or shared detector is given to an input terminal pulled up or pulled down through a first resistor, and the electric motor is based on the given detection signal Or in a power steering device that drives and controls a hydraulic actuator,
One or a plurality of second resistors for pulling up or pulling down the input terminal, one or a plurality of switching elements for bringing the second resistor into an energized state or a non-energized state, and an external setting should be accepted and mounted Setting means for setting on / off of the switching element according to the type of vehicle when the detector is occupied and when the detector is shared with other devices. A featured power steering device. 2. The power steering apparatus according to claim 1, further comprising a switching element that causes the first resistor to be in an energized state or a non-energized state, and a setting unit that receives an external setting and sets the on / off state of the switching element. The setting unit includes a nonvolatile memory that stores the setting by communication from the outside, and is configured to set on / off of the switching element in accordance with the setting stored in the nonvolatile memory. Item 3. The power steering device according to Item 1 or 2. The power steering apparatus according to any one of claims 1 to 3, wherein the detector is a steering angle detector that detects a steering angle of a steering member.

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