JP5219763B2 - Steering control device - Google Patents

Description

  The present invention relates to a steering control device that assists a driver's steering force with hydraulic pressure, and more particularly to a steering control device used for a large vehicle.

Conventionally, in the power steering device disclosed in Patent Document 1, the steering shaft is driven by supplying the hydraulic pressure from the pump to the input shaft drive unit for generating torque in the left and right rotational directions, and automatic steering is performed. It is possible. The rotary valve is configured to selectively supply hydraulic oil supplied from the pump to the reservoir tank or the power cylinder. Further, the rotary valve is connected to the left and right rotational direction torque generating input shaft drive unit, and the left and right rotational direction torque generating input shaft drive unit is driven and controlled using the discharge pressure of the pump. .
JP 2007-168673 A

  In the above prior art, in the neutral state of the steering shaft, the hydraulic oil supplied from the pump is directly discharged to the reservoir tank via the rotary valve, so that the pressure in the hydraulic circuit does not increase. In order to increase the drive torque of the input shaft drive unit for generating the left and right rotational direction torque using this pressure, a throttle may be provided on the upstream side of the reservoir tank.

  However, when the pressure in the hydraulic circuit is increased by providing a throttle and the driving torque is increased, there is a problem that the driving load of the pump is always increased by the throttle and the fuel efficiency is deteriorated.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a steering control device in which the driving load of the pump is reduced and the fuel consumption performance is improved.

In order to achieve the above object, according to the first aspect of the present invention, the first steering shaft drive unit that is connected to the rotary valve and applies a rotational force in the clockwise direction to the steering wheel , and the rotary valve are connected to the steering wheel. a second steering shaft driving unit for applying a rotary force in the counterclockwise direction with respect to, provided in the first communication passage on for communicating the rotary valve and the first steering shaft driving unit, and blocking communication of the first communication passage a first solenoid valve for switching control, is provided on the second communication passage for communicating the rotary valve and the second steering shaft driving unit, and a second solenoid valve for controlling switching and blocking communication of the second communication path, create dynamic provided in the third communication passage on connecting the reservoir tank and the rotary valve for storing oil, and a third solenoid valve which controls switching and blocking communication of the third communication passage Information signal traveling state or a driver's driving state of the vehicle is input, the first solenoid valve, the second solenoid valve, and a third have a control circuit for driving and controlling the solenoid valve, the first steering shaft driving unit When the first solenoid valve is opened, it is driven by the pressure of the hydraulic oil supplied through the first communication path to apply a clockwise rotational force to the steering wheel. When the second solenoid valve is opened, it is driven by the pressure of the hydraulic oil supplied through the second communication path to apply a counterclockwise rotational force to the steering wheel. Based on the information signal of the driving state, it is determined whether to apply a clockwise rotational force or a counterclockwise rotational force to the steering wheel. Based on the result of the determination, a valve opening command signal is output to the first solenoid valve or the second solenoid valve, and a command signal is output to the third solenoid valve, including the first communication path and the second communication path. In order to increase the pressure in the hydraulic circuit, the oil passage area of the third communication path is reduced, and the outflow of hydraulic oil from the hydraulic circuit to the reservoir tank is suppressed .

  Therefore, a steering control device with improved fuel efficiency can be provided.

  Hereinafter, the best mode for realizing a steering control device of the present invention will be described based on an embodiment shown in the drawings.

[System configuration]
Example 1 will be described. FIG. 1 is a system configuration diagram of the power steering apparatus of the present application.

  The power steering apparatus 1 includes a steering wheel SW, an input shaft 4, a link mechanism 5, an output shaft 6, a steered wheel 7, a pressure control mechanism 10, a piston housing 11b, a steering shaft drive unit 400, a pump P, a power supply B, and a control unit. It has a CU (control circuit).

  The solenoid valves 100 to 300 (described later) in the pump P, the control unit CU, and the pressure control mechanism 10 are driven by the power of the power source B. The pump P supplies hydraulic oil to the piston housing 11b, and the movement of the piston housing 11b is transmitted from the output shaft 6 to the link mechanism 5 so that the steered wheels 7 are steered.

  The steering wheel SW is connected to the piston housing 11b via the input shaft 4, and a rotary valve 600 (see FIG. 3) is provided in the piston housing 11b. The rotary valve 600 distributes the discharge pressure of the pump P to the pressure chambers 21 and 22 (see FIG. 3) according to the rotation direction of the input shaft 4 to perform steering assist (normal steering assist).

  The steering shaft drive unit 400 is a hydraulic actuator that applies torque in the left-right rotation direction to the input shaft 4 by hydraulic pressure. The pressure control mechanism 10 supplies hydraulic oil discharged from the pump P to the steering shaft driving unit 400 based on a command from the control unit CU, and rotates the input shaft 4 (automatic steering).

  Further, at high vehicle speed, a torque in the opposite direction to the driver's steering input is applied to the input shaft 4 based on a command from the control unit CU, and a reaction force against the driver's steering input is applied (steering reaction force control (SSPS control)). mode)).

  The control unit CU includes environmental information detection devices (vehicle speed sensor 6a, steering sensor 6b (steering angle sensor, torque sensor, etc.), lane recognition sensor 6c, vehicle state sensor 6d (yaw rate sensor, lateral G sensor, etc.), and inter-vehicle distance sensor 6e. , Lane departure warning switch 6f, automatic steering request switch 6g), and steering shaft drive unit 400 is driven via pressure control mechanism 10 based on signals from pressure sensor 6h to perform automatic steering or steering reaction force control. .

  The control unit CU includes a transistor Tr therein, and supplies current to solenoid valves 100 to 300 (described later) in the steering shaft driving unit 400 via the transistor Tr to perform automatic steering or steering reaction force control. By controlling the control amount for the transistor Tr, the opening degree of each of the solenoid valves 100 to 300 is controlled to obtain a desired control state.

  Further, the control unit CU activates the alarm device 6h when it is determined that the vehicle is departing from the lane. By driving the steering shaft drive unit 400 via the pressure control mechanism 10, the input shaft 4 may be rotated alternately to the left and right to vibrate the steering wheel SW, and a warning may be issued to the driver.

[Hydraulic circuit]
FIG. 2 is a hydraulic circuit diagram. The pressure control mechanism 10 includes left and right solenoid valves 100 and 200 that apply a lateral torque to the steering shaft 2, and a back pressure solenoid valve 300 that controls a back pressure in the hydraulic circuit. The left and right solenoid valves 100 and 200 are normally closed, and the back pressure solenoid valve 300 is a normally open solenoid valve. In the first embodiment, the left and right solenoid valves 100 and 200 are proportional valves and the back pressure solenoid valve 300 is on.・ Off valve.

  The rotary valve 600 is connected to the pump P through the oil passage d1, and is connected to the reservoir tank 5 through the oil passage d2. The oil passage d2 is provided with a fixed orifice 500, and the back pressure solenoid valve 300 and the fixed orifice 500 are connected in parallel between the rotary valve 600 and the reservoir tank 5.

  The left and right solenoid valves 100 and 200 are connected to the rotary valve 600 via the upstream first and second communication passages a1 and b1, respectively, and to the left via the downstream first and second communication passages a2 and b2. The right steering shaft driving units 410 and 420 are connected. Moreover, it connects with the reservoir tank 5 through oil path a3, b3.

  The solenoid valves 100 and 200 are solenoid valves that are driven by solenoids SOL1 and SOL2, respectively, and switch communication / blocking between the left and right solenoid valves 100 and 200 and the pump P or the reservoir tank 5.

  When the steering shaft driving units 410 and 420 and the pump P are communicated with the left and right solenoid valves 100 and 200, the steering shaft driving units 410 and 420 are disconnected from the reservoir tank 5. On the other hand, when the respective steering shaft driving units 410 and 420 and the reservoir tank 5 are communicated, the respective steering shaft driving units 410 and 420 are disconnected from the pump P.

  The left and right steering shaft drive units 410 and 420 are actuators that respectively apply left and right torques to the input shaft 4, and function as reaction force actuators based on hydraulic pressure input from the pump P. On the other hand, when automatic steering control is required, such as when the driver is falling asleep or driving aside, it functions as a steering actuator that rotates the input shaft 4 to drive the rotary valve 600 and performs steering assist in the direction of torque application. (Details will be described later).

  The back pressure solenoid valve 300 is connected to the rotary valve 600 via the upstream third communication passage c1, and is connected to the reservoir tank 5 via the downstream third communication passage c2. The rotary valve 600 and the reservoir tank 5 are communicated / blocked by the back pressure solenoid valve 300.

  By turning off the back pressure solenoid valve 300, the hydraulic oil discharged from the rotary valve 600 is all supplied to the steering shaft driving units 410 and 420 except for the outflow from the fixed orifice 500. As a result, the discharge pressure of the pump P is efficiently applied to the steering shaft driving units 410 and 420.

  Further, by connecting the rotary valve 600 and the reservoir tank 5 via the fixed orifice 500, the pressure of the rotary valve 600 is prevented from becoming excessive even when the back pressure solenoid valve 300 is closed.

  When the discharge pressure of the pump P is introduced into the right steering pressure chamber 21 (first pressure chamber) of the cylinder 10, the volume of the right steering pressure chamber 21 increases and the piston 70 moves in the right assist direction. When the discharge pressure is introduced into the left steering pressure chamber 22 (second pressure chamber), the piston 70 moves in the left assist direction. Thus, steering assist is performed (see FIGS. 15 and 16).

  The upstream third communication passage c1 is provided with a pressure sensor 6h, which outputs the pressure between the rotary valve 600 and the back pressure solenoid valve 300 to the control unit CU.

[Axial sectional view]
3 is an axial sectional view of the power steering apparatus 1, and FIGS. 4 to 6 are external views. 4 is a front view in the y-axis positive direction, FIG. 5 is a front view in the z-axis negative direction, and FIG. 6 is an enlarged view of the vicinity of the back pressure solenoid valve 300 in FIG. The axial direction of the input / output shafts 4 and 6 is defined as the y-axis, and the input shaft 4 side is positive. Further, the sector shaft 30 side is defined as the x-axis positive direction when viewed from the piston 70 side, and the input shaft 4 side is defined as the z-axis positive direction orthogonal to the x and y axes and viewed from the back pressure solenoid valve 300.

  7 is an axial sectional view of the input / output shafts 4 and 6, FIG. 8 is an enlarged view of the outer periphery of the inner valve portion 610, and FIG. 9 is a sectional view taken along line II in FIG. 10 is a cross-sectional view of the vicinity of the left solenoid valve 100, FIG. 11 is a cross-sectional view of the vicinity of the right solenoid valve 200, and FIG. 12 is a cross-sectional view of the vicinity of the back pressure solenoid valve 300.

  The housing 11 of the power steering apparatus 1 includes a valve housing 11a that houses a rotary valve 600 that switches an assist direction, and a piston housing 11b that houses a piston 70 that generates an assist force by hydraulic pressure. The power steering device 1 has a sector shaft 30 that meshes with the piston 70 and rotates by the reciprocating motion of the piston 70 to steer the steered wheels 7.

  Both the valve housing 11a and the piston housing 11b are substantially cup-shaped members and are connected to each other in the axial direction opening. The input shaft 4 is inserted into the bottom of the valve housing 11a in the axial direction.

  In accordance with the rotation of the input shaft 4, the piston 70 in the piston housing 11b is slid in the axial direction by hydraulic pressure. The valve housing 11a is provided with a suction port IN and a discharge port OUT for supplying and discharging hydraulic oil.

  The piston housing 11b and the sector shaft 30 are provided at right angles to each other in the axial direction. The teeth provided on the piston 70 in the piston housing 11b and the teeth provided on the sector shaft 30 mesh with each other. Steering assist is performed by rotating the shaft 30.

  The piston 70 is accommodated in the piston housing 11b so as to be movable in the axial direction. By this piston 70, the piston housing 11b is supplied to the right steering pressure chamber 21 on the input shaft 4 side and the left steering pressure chamber 22 on the cup-shaped bottom side. It is separated and kept dense.

  The input shaft 4 is connected to the output shaft 6 by a torsion bar 50. The output shaft 6 is inserted into the piston 70 in the axial direction, and is fitted to the piston 70 by a ball screw mechanism 60a. Further, a piston tooth portion 71 carved in the circumferential direction is provided on the outer periphery of the piston 70, and the piston 70 meshes with the sector shaft 30 in the piston tooth portion 71.

  The piston housing 11b is provided so that its axis is orthogonal to the sector shaft 30, and a sector shaft storage portion 23 for storing a part of the sector shaft 30 is provided in a part of the piston housing 11b in the radial direction. The sector shaft storage portion 23 is supplied with hydraulic oil and communicates with the right steering pressure chamber 21 to perform lubrication in the engagement between the sector shaft 30 and the piston tooth portion 71.

  The right steering pressure chamber 21 in the piston housing 11b communicates with the rotary valve 600 by an oil passage 15 provided across the piston housing 11b and the valve housing 11a, and the left steering pressure chamber 22 is an oil passage provided in the valve housing 11a. 16 communicates with the rotary valve 600.

  The rotary valve 600 includes an inner valve portion 610 formed on the outer periphery of the input shaft 4 and an outer valve portion 620 formed on the inner periphery of the output shaft 6. The inner valve portion 610 is formed by recessing a cylindrical member provided on the outer periphery of the input shaft 4 in the inner peripheral direction, and the outer valve portion 620 is formed by recessing the inner periphery of the output shaft 6 on the outer peripheral side.

  The inner valve portion 610 has a first valve groove 611 (valve portion) recessed in the inner diameter direction, and the outer valve portion 620 has a second valve groove 621 (valve portion) recessed in the outer diameter direction. A plurality of first and second valve grooves 611 and 621 are provided in the circumferential direction.

  The rotary valve 600 introduces or discharges hydraulic oil from the suction port IN and the discharge port OUT to the right and left steering pressure chambers 21 and 22 according to the rotation of the input shaft 4. When the input shaft 4 rotates relative to the right side with respect to the output shaft 6, the pump P communicates with the right steering pressure chamber 21, and when rotated relative to the left side, the pump P communicates with the left steering pressure chamber 22.

  Further, left and right steering shaft driving units 410 and 420 are provided at the overlapping portion of the input shaft 4 and the output shaft 6 on the negative side of the rotary valve 600 in the y-axis direction. The left and right steering shaft driving portions 410 and 420 are provided with radial holes 410a and 420a on the output shaft 6 from the central axis toward the outer diameter side, and the pistons 411 and 421 are received in the radial holes 410a and 420a, respectively. It is formed by wearing.

Left and right pressure chambers 412 and 422 are formed on the outer diameter sides of the pistons 411 and 421 in the radial holes 410a and 420a, respectively , and are connected to the left and right solenoid valves 100 and 200, respectively. The left direction pressure chamber 412 is connected to the left direction solenoid valve 100 via the downstream side first communication path a2, and the right direction pressure chamber 422 is connected to the right direction solenoid valve 200 via the downstream side second communication path b2.

  On the other hand, a fixed orifice 500 is provided on the positive side of the rotary valve 600 in the y-axis direction. The fixed orifice 500 is provided on the outer peripheral surface 610a of the inner valve portion 610, with the y-axis positive direction side of the inner valve groove 611 cut out to the inner peripheral side, and has a planar shape over a predetermined circumferential range of the inner valve outer peripheral surface 610a. 4 are small diameter portions formed at four locations.

  A gap with a predetermined interval is formed between the fixed orifice 500 and the outer valve portion 620. On the other hand, the drain oil passage OUT ′ is configured to communicate with the fixed orifice 500 through a gap between the inner valve portion 610 and the outer valve portion 620.

  Since the fixed orifice 500 is positioned on the discharge oil passage OUT ′ connecting the rotary valve 600 and the reservoir tank 5, the pressure in the rotary valve 600 becomes excessive while keeping the pressure in the rotary valve 600 at a certain value or more. To prevent that.

  The fixed orifice 500 is formed only by reducing the diameter of a part of the inner valve portion 610, and the number of processing steps is reduced. Further, by forming the fixed orifice 500 in a planar shape over a predetermined range in the circumferential direction of the inner valve portion 610, abnormal noise when the hydraulic fluid passes through the fixed orifice 500 is suppressed.

  A left solenoid valve 100 (first solenoid valve) and a right solenoid valve 200 (second solenoid valve) that perform hydraulic pressure control are provided on the outer periphery of the valve housing 11a. The left solenoid valve 100 is provided on the x-axis negative direction side of the valve housing 11a, and communicates / blocks the rotary valve 600 and the left-direction steering shaft drive unit 410 via the upstream first communication passage a1.

  The right solenoid valve 200 is provided on the negative z-axis direction side of the left solenoid valve 100, and communicates / blocks the rotary valve 600 and the right steering shaft drive unit 420 via the upstream second communication passage b1. . By supplying pump pressure to the left and right steering shaft driving units 410 and 420 via the solenoid valves 100 and 200, the pistons 411 and 421 are moved in the inner circumferential direction, and serrations provided on the input shaft 4 are provided. The groove 41 is pressed to apply a torque in the left-right rotation direction to the input shaft 4.

[Details of steering shaft drive]
13 and 14 are radial cross-sectional views of the left and right direction steering shaft driving units 410 and 420. 13 is a II-II cross section of FIG. 7, and FIG. 14 is a III-III cross section.

  The radial holes 410a and 420a of the left and right steering shaft driving units 410 and 420 are provided from the central axis of the output shaft 6 toward the outer diameter side, and accommodate the pistons 411 and 421, respectively. Eight radial holes 410a and 420a are provided at equal intervals in the circumferential direction of the output shaft 6, and left and right pressure chambers 412 and 422 are formed on the outer diameter sides of the pistons 411 and 421, respectively.

  Further, substantially spherical contact portions 413 and 423 are provided at the inner diameter side end portions of the respective pistons 411 and 421. As the pistons 411 and 421 move toward the inner diameter side due to the hydraulic pressure in the directional pressure chambers 412 and 422, the contact portions 413 and 423 press the serration grooves 41 of the input shaft 4.

Here, the left and right steering shaft driving units 410 and 420 are provided with their rotational positions shifted from each other. That is, the BB line and the B′-B ′ line that are the axial lines of the radial holes 410 a and 420 a of the left and right steering shaft driving units 410 and 420, and the deepest groove 41 of the input shaft serration groove 41 facing each other a -A line connecting parts, A'-a 'line is the angle theta / 2 offset each other.

Therefore, the right abutment 423 presses the input shaft 4 at the left inclined face 43 of the line-side 'B'-B to line'A'-A, the left contact portion 413 relative to A -A line The input shaft 4 is pressed in the counterclockwise rotation direction on the left rotation convex slope surface 42 on the B-B line side.

  Since the input shaft 4 can rotate with a predetermined allowable amount, the input shaft 4 rotates counterclockwise. On the other hand, the right contact portion 423 presses the right inclined surface 43 of the serration groove 41 and similarly rotates the input shaft 4 in the right direction.

[Hydraulic circuit during normal steering assist]
15 and 16 are hydraulic circuit diagrams during normal steering assist. FIG. 15 shows the left steering assist state, and FIG. 16 shows the right steering assist state. In FIGS. 15 to 21, the thick line in the hydraulic circuit is a high pressure, the thin line is a low pressure, and the middle thick line is a medium pressure.

  At the time of normal steering assist, the normally closed solenoid valves 100 and 200 are in a non-energized state, and are upstream first communication passage a1, downstream first communication passage a2, upstream second communication passage b1, and downstream second communication. The passages b2 are blocked.

  On the other hand, the normally open back pressure solenoid valve 300 is deenergized and opened, and the rotary valve 600 and the reservoir tank 5 are connected through both the fixed orifice 500 and the back pressure solenoid valve 300.

(Normal left steering assist)
When the steering wheel SW is steered to the left by the driver, only the pump P, the oil passage 16, and the upstream second communication passage b1 communicate with each other by the relative rotation of the inner valve portion 610 and the outer valve portion 620 of the rotary valve 600, and the pump discharge pressure Is introduced into the left steering pressure chamber 22. On the other hand, the oil passage 15, the upstream first communication passage a1, and the oil passages d2, c1 are disconnected from the pump P.

  Since the right solenoid valve 200 connected to the upstream second communication passage b <b> 1 is in a closed state, all the discharge pressure of the pump P acts on the left steering pressure chamber 22 via the oil passage 16. As a result, the piston 70 moves in the left assist direction, and left steering assist is performed.

(Normally right steering assist)
When the steering wheel SW is steered to the right, the pump P communicates with the oil passage 15 and the upstream first communication passage a1 by the rotary valve 600, and the pump discharge pressure is introduced into the right steering pressure chamber 21. The oil passage 16, the downstream first communication passage a2, and the oil passages d1 and c1 are disconnected from the pump P.

  As with the left steering assist, the left solenoid valve 100 connected to the upstream first communication passage a1 is normally closed during normal operation, so that the discharge pressure of the pump P is all right via the oil passage 15. Acts on the chamber 21. As a result, the piston 70 moves in the right assist direction, and right steering assist is performed.

[Hydraulic circuit during automatic steering]
17 to 19 are hydraulic circuit diagrams at the time of automatic steering. 17 shows an automatic steering preparation state, FIG. 18 shows a left turn automatic steering state, and FIG. 19 shows a right turn automatic steering state. In addition, the middle line (medium pressure) of FIGS. 17-19 is a pilot pressure, and is the pressure which the pump P discharges in advance for automatic steering preparation.

(Automatic steering preparation)
When automatic steering is performed from the steering neutral state, the normally open back pressure solenoid valve 300 is first closed, and the upstream side first and second oil passages that are the pump P side (upstream side) oil passages of the left and right solenoid valves 100 and 200. Pump pressure is applied to the communication passages a1 and b1, and the pressures of the upstream first and second communication passages a1 and b1 are increased.

  For this reason, when the left and right solenoid valves 100 and 200 are opened, the hydraulic oil having a high pressure is supplied to the left and right steering shaft driving units 410 and 420 in advance. This makes it possible to speed up the response when the input shaft 4 is rotated by the left and right direction steering shaft driving units 410 and 420.

(Automatic steering left turn)
When turning left by automatic steering, the left solenoid valve 100 is opened and the pump discharge pressure is introduced into the left steering shaft drive unit 410. On the other hand, both the right direction solenoid valve 200 and the back pressure solenoid valve 300 are closed.

  As a result, the input shaft 4 is rotated in the left steering direction by the left steering shaft driving unit 410, and the pump discharge pressure is supplied to the left steering pressure chamber 22 by the relative rotation with the output shaft 6 in the rotary valve 600. Thereby, the left turn by automatic steering is performed. The solenoid valve 300 for back pressure is closed at the time of preparation for left automatic steering, and the left-hand steering shaft drive unit 410 is driven promptly by making the hydraulic circuit high in advance.

(Automatic steering right turn)
When turning right by automatic steering, the right solenoid valve 200 is opened and the pump discharge pressure is introduced into the right steering shaft drive unit 420. On the other hand, both the left solenoid valve 100 and the back pressure solenoid valve 300 are closed.

  As a result, the input shaft 41 is rotated in the right steering direction by the right steering shaft driving unit 420, the pump pressure is introduced into the right steering pressure chamber 21, and a right turn is performed by automatic steering. The solenoid valve 300 for back pressure is closed at the time of preparation for automatic steering, and the right-hand steering shaft drive unit 420 is driven quickly by setting the hydraulic circuit to a high pressure in advance.

[Hydraulic circuit during steering reaction force control (SSPS control)]
20 and 21 are hydraulic circuit diagrams at the time of steering reaction force control (SSPS mode). 20 shows a case where a reaction force in the right direction is applied to the driver's left steering input, and FIG. 21 shows a case in which a reaction force in the left direction is applied to the driver's right steering input. 20 and 21, the middle line (medium pressure) is the actuator operating pressure that is reduced by the solenoid valves 100 and 200 to drive the steering shaft driving units 410 and 420.

(Fig. 20: SSPS mode during left steering)
When the SSPS mode is executed when the driver is performing left steering, the right solenoid valve 200 is opened in the normal left steering assist state (see FIG. 15), and the pump discharge pressure is driven to the right steering shaft. Part 420 is introduced.

  As a result, a torque in the right steering direction is applied to the input shaft 4, and a reaction force is applied to the left steering input by the driver. When the vehicle is traveling at high speed, the vehicle behavior changes with respect to the steering input. Therefore, the vehicle behavior becomes more stable when the steering reaction force against the steering by the driver is larger. Therefore, when the driver performs left steering at a high vehicle speed, the SSPS control mode is executed and a right steering direction torque opposite to the steering input is applied to the input shaft 4 to avoid a sudden change in vehicle behavior. .

(Fig. 21: SSPS mode during right steering)
As in the case of left steering, when the SSPS mode is executed during right steering, the left solenoid valve 100 is opened in the normal right steering assist state (see FIG. 16), and the pump discharge pressure is set to the left steering shaft drive unit. 410.

  As a result, a torque in the left steering direction is applied to the input shaft 4, a reaction force is applied to the right steering input by the driver, and a sudden change in the vehicle behavior is avoided.

[Control flow]
(Main flow)
FIG. 22 is a main flow of the present application. Details of each step will be described later.
In step S1, initial abnormality determination is performed, and the process proceeds to step S2.
In step S2, system abnormality determination is performed, and the process proceeds to step S3.
In step S3, energization amount command values for the solenoid valves 100 to 300 are set, and the process proceeds to step S4.
In step S4, the solenoid valves 100 to 300 are driven, and the process returns to step S2.

(Initial abnormality judgment flow)
FIG. 23 is an initial abnormality determination flow (FIG. 22: step S1). If the pressure in the circuit detected by the pressure sensor 6h is less than a predetermined value, an abnormality is determined that the pressure does not increase. As the cause of the abnormality, there is a high possibility of malfunction of the back pressure solenoid valve 300 that discharges the pressure in the circuit to the reservoir tank 5, and therefore it is determined that the back pressure solenoid valve 300 is abnormal.
In step S101, the first and second solenoids SOL1, SOL2 provided in the left and right solenoid valves 100, 200 are de-energized, and the process proceeds to step S102.
In step S102, the third solenoid SOL3 provided in the back pressure solenoid valve 300 is energized with a predetermined value, and the process proceeds to step S103.
In step S103, the pressure value (pressure in the hydraulic circuit) detected by the pressure sensor 6h is read, and the process proceeds to step S104.
In step S104, energization of the third solenoid SOL3 is stopped, and the process proceeds to step S105.
In step S105, it is determined whether or not the pressure value detected in step S103 <the predetermined value. If YES, the process proceeds to step S106, and if NO, the control is terminated.
In step S106, the abnormality flag of the third solenoid SOL3 is set to 1 (abnormal), and the control is terminated.

(Abnormality judgment flow)
FIG. 24 is an abnormality determination flow (corresponding to step S2 in FIG. 22). When the system fails, all the solenoid valves 100 to 300 are set in a non-energized state (a state in which steering assist is possible).
In step S201, it is determined whether or not an abnormality has occurred in each of the solenoid valves 100 to 300, the control signal input to the control unit CU, and the control unit CU itself. If any one of them is abnormal, the process proceeds to step S202, and if all are normal, the process proceeds to step S203.
In step S202, it is determined that an abnormality has occurred, the energization permission amount of the first to third solenoids SOL1 to SOL3 provided in the solenoid valves 100 to 300 is set to 0, and the control is terminated as a steering assistable state. The normally closed solenoid valves 100, 200 in the left-right direction are closed, and the back pressure solenoid valve 300, which is normally open, is opened.
In step S203, energization of the first to third solenoids SOL1 to SOL3 is permitted, and the control ends.
When a system abnormality occurs, the steering assist force is ensured even when the abnormality occurs by shifting to a state where normal steering assist is possible. In the normal steering assist state (see FIGS. 15 and 16), the discharge pressure of the pump P is introduced into the left and right pressure chambers 21 and 22 even when the back pressure solenoid valve 300 is open as in step S202. Steering assist can be performed.
Further, by opening the back pressure solenoid valve 300 at the time of abnormality, even if the left and right solenoid valves 100 and 200 are opened, the discharge pressure of the pump P passes through the back pressure solenoid valve 300. Since the liquid is discharged to the reservoir tank 5, the hydraulic pressure of the steering shaft driving units 410 and 420 does not rise sufficiently. Therefore, when an abnormality occurs in the apparatus, the steering assist can be continued without being affected by the steering shaft driving units 410 and 420.
Further, the back pressure solenoid valve 300 is normally open and is opened in a non-energized state. For this reason, when the back pressure solenoid valve 300 fails and becomes non-energized, the third communication passages c1 and c2 are in communication, and the rotary valve 600 and the reservoir tank 5 are in communication with each other, so that the hydraulic pressure in the circuit is excessive. It will never be. Therefore, the load of the pump P at the time of failure is reduced.

(Energization amount command value setting flow)
FIG. 25 is a flowchart for setting energization amount command values for the first to third solenoids SOL1 to SOL3 provided in the solenoid valves 100 to 300 (FIG. 22: step S3).
In step S301, it is determined whether or not there is a control request for each solenoid SOL1-SOL3. If there is a control request, the process proceeds to step S302, and if not, the process proceeds to step S305.
In step S302, it is determined whether or not the mode is the SSPS control (steering reaction force control) mode. If YES, the process proceeds to step S303, and if NO, the process proceeds to step S304.
Since the SSPS control mode is set in step S303, the energization permission amount for the third solenoid SOL3 of the back pressure solenoid valve 300 is set to 0, and the process proceeds to step S306.
In the SSPS control mode, the normally open back pressure solenoid valve 300 is opened, and therefore it is not necessary to drive the third solenoid SOL3. Therefore, the energization amount command value for the third solenoid SOL3 of the back pressure solenoid valve 300 is set to zero.
In step S304, energization of the third solenoid SOL3 is permitted to execute control (steering wheel vibration generation or automatic steering) other than the SSPS control mode, an energization amount command value is calculated, and the process proceeds to step S308.
In step S305, since there is no control request for each of the solenoids SOL1 to SOL3, the energization permission amount for the third solenoid SOL3 is set to 0, and the process proceeds to step S309.
In step S306, the vehicle speed is read, and the process proceeds to step S307.
In step S307, in order to execute the SSPS control mode, the energization amount command values for the first and second solenoids SOL1, SOL2 of the left and right solenoid valves 100, 200 that are proportional valves are set according to the vehicle speed, and the input shaft 4 On the other hand, the steering reaction force according to the vehicle speed is appropriately applied to end the control.
In step S308, energization amount command values for the first and second solenoids SOL1 and SOL2 are set in order to execute control (steering wheel vibration generation or automatic steering) other than the SSPS control mode, and the control ends.
In step S309, the energization amount command value for the first and second solenoids SOL1, SOL2 is set to 0, and the control is terminated.
At the time of steering wheel vibration generation and automatic steering , the back pressure solenoid valve 300 reduces the oil passage area of the third communication passages c1 and c2, and the pressure in the hydraulic circuit increases. Thereby, the drive torque of the left and right direction steering shaft drive units 410 and 420 is efficiently increased.
Further, when the left and right steering shaft driving units 410 and 420 are not driven, such as during normal steering assist, the pump P is driven by reducing the throttle amount of the back pressure solenoid valve 300 which is an on / off valve to zero. Reduce the load. Since the back pressure solenoid valve 300 is an on / off valve, the back pressure solenoid valve 300 is inexpensive, and the calculation load and control configuration of the control unit CU for controlling the back pressure solenoid valve 300 are simplified.

(Energization drive flow)
FIG. 26 is an energization drive flow (FIG. 22: step S4). It implements individually with respect to each solenoid valve 100-300.
In step S401, it is determined whether the energization permission amount = 0 or not. If YES, the process proceeds to step S404, and if NO, the process proceeds to step S402.
In step S402, the energization amount command value is read, and the process proceeds to step S403.
In step S403, the transistor Tr is driven based on the energization amount command value, and energization is performed to the solenoids SOL1 to SOL3, and the control ends.
In step S404, the driving amount of the transistor Tr is set to 0, and the control ends.

[Effect of Example 1]
(1) housing 11;
An input shaft 4 connected to the steering wheel SW and rotatably accommodated in the housing 11;
An output shaft 6 rotatably accommodated in the housing 11 and connected to the input shaft 4 so as to be relatively rotatable;
A piston 70 housed in the housing 11 and separating the inside of the housing 11 into a right steering pressure chamber 21 and a left steering pressure chamber 22;
The hydraulic fluid that is provided in the housing 11 and is supplied from the pump P by the relative rotation of the input shaft 4 and the output shaft 6 is transferred to the right steering pressure chamber 21 (first pressure chamber) and the left steering pressure chamber 22 (second pressure chamber). A rotary valve 600 to selectively supply;
A ball screw mechanism 60a (conversion mechanism) that converts rotation of the output shaft 6 into axial movement of the piston 70;
A sector shaft 30 (transmission mechanism) that transmits the axial movement of the piston 70 to the steering wheel;
A left-hand steering shaft driving unit 410 (first steering shaft driving unit) that is connected to the rotary valve 600 and applies a rotational force to the steering wheel SW;
A right steering shaft drive unit 420 (second steering shaft drive unit) that is connected to the rotary valve 600 and applies a rotational force in the opposite direction to the left steering shaft drive unit 410 to the steering wheel SW;
The first communication passages a1 and a2 are provided on the first communication passages a1 and a2 communicating with the rotary valve 600 and the left steering shaft driving unit 410. A left-hand solenoid valve 100 (first solenoid valve) for switching and controlling the shutoff;
The second communication passages b1 and b2 are provided on the second communication passages b1 and b2 that connect the rotary valve 600 and the right steering shaft drive unit 420. The communication between the second communication passages b1 and b2 is based on the traveling state of the vehicle or the driving state of the driver. A right-hand solenoid valve 200 (second solenoid valve) for switching and controlling the shutoff;
Provided on the third communication passages c1 and c2 that connect the reservoir tank 5 that stores the hydraulic oil supplied from the pump P and the rotary valve 600, the left steering shaft driving unit 410 or the right steering shaft driving unit 420 is provided. When the drive control is performed, the back pressure solenoid valve 300 (third solenoid valve) for reducing the oil passage area of the third communication passages c1 and c2 is provided.
The back pressure solenoid valve 300 reduces the oil passage area of the third communication passages c1 and c2, and the pressure in the hydraulic circuit increases. As a result, the driving torque of the left and right steering shaft driving units 410 and 420 can be increased efficiently. Further, when the left and right steering shaft driving units 410 and 420 are not driven, the driving load of the pump P can be reduced by reducing or reducing the throttle amount of the back pressure solenoid valve 300.

(2) (20) The left solenoid valve 100 and the right solenoid valve 200 are configured to be closed in a non-energized state.
As a result, when a failure occurs, the solenoid valves 100 and 200 are closed, and a hydraulic circuit that is not affected by the solenoid valves 100 and 200 is configured. Therefore, the steering assist can be continued even when the solenoid valves 100 and 200 are in failure.

(3) A control unit CU (control circuit) for driving and controlling the left-side solenoid valve 100, the right-side solenoid valve 200, and the back pressure solenoid valve 300, and for inputting a running state or driving state information signal,
The first, second and back pressure solenoid valves 100, 200, 300 and the control unit CU are supplied with power from the power source B,
When the control unit CU detects an abnormality in each of the solenoid valves 100 to 300, the information signal input to the control unit CU, the power supply B, and the control unit CU itself, the control unit CU turns off all the solenoid valves 100 to 300. Control was made so that the energized state was obtained.
Thereby, at the time of failure, the hydraulic circuit which is not influenced by all the solenoid valves 100 to 300 can be configured, and the steering assist can be continued.

(4) It further includes a fixed orifice 500 in which the flow path area is kept constant,
The fixed orifice 500 is provided in parallel with the back pressure solenoid valve 300 and on an oil passage d2 (flow passage) connecting the reservoir tank 5 and the rotary valve 600.
Even when the back pressure solenoid valve 300 is fixed in a closed state, the minimum flow rate from the rotary valve 600 to the reservoir tank 5 can be secured through the fixed orifice 500.

(5) The rotary valve 600 is
An inner valve portion 610 provided on the input shaft 4;
An outer valve portion 620 provided on the output shaft 6 so as to surround the inner valve portion 610;
Formed on the outer peripheral surface of the inner valve portion 610 and the inner peripheral surface of the outer valve portion 620, the hydraulic fluid supplied from the pump P is supplied to the right steering pressure chamber 21 and the left steering pressure chamber 22 by the relative rotation of the input shaft 4 and the output shaft 6. Valve grooves 611 and 621 (valve portions) for switching oil passages so as to be selectively supplied to
A supply oil passage IN ′ formed in the outer valve portion 620 and supplying hydraulic fluid supplied from the pump P to the valve grooves 611 and 621;
Formed in the outer valve portion 620, and is constituted by a discharge oil passage OUT ′ for discharging the hydraulic fluid in the valve grooves 611 and 621 to the reservoir tank 5,
The fixed orifice 500 is provided on the outer peripheral surface of the inner valve portion 610 and closer to the input shaft 4 than the valve grooves 611 and 621, and the inner valve portion 610 has a predetermined gap between the outer valve portion 620. It is constituted by a small diameter portion formed over a predetermined range in the circumferential direction,
The drain oil passage OUT ′ is configured to communicate with the fixed orifice 500 through a gap between the inner valve portion 610 and the outer valve portion 620.
The fixed orifice 500 can be formed simply by reducing the diameter of a part of the inner valve portion 610. Further, by forming the fixed orifice 500 over a predetermined range in the circumferential direction of the inner valve portion 610, it is possible to suppress abnormal noise when the hydraulic fluid passes through the fixed orifice 500.

(6) (16) The rotary valve 600 is
When the steering wheel SW is steered counterclockwise, more hydraulic fluid from the pump P is supplied to the first pressure chamber than to the second pressure chamber,
When the steering wheel SW is steered clockwise, it is configured to supply more hydraulic fluid from the pump P to the second pressure chamber than to the first pressure chamber.
When the left solenoid valve 100 is opened and the pressure in the first pressure chamber is supplied to the left steering shaft driving unit 410, the left steering shaft driving unit 410 rotates clockwise in the steering wheel SW. Give power,
When the right solenoid valve 200 is opened and the pressure in the second pressure chamber is supplied to the right direction steering shaft drive unit 420, the right direction steering shaft drive unit 420 turns the steering wheel SW counterclockwise. Giving a rotational force,
When the vehicle speed is higher than the specified value,
The back pressure solenoid valve 300 is driven and controlled so that the flow passage areas of the third communication passages c1 and c2 are maximized,
The left solenoid valve 100 is driven and controlled so that the first communication passages a1 and a2 are in communication.
The right solenoid valve 200 is driven and controlled so that the second communication passages b1 and b2 are in a communication state.
In a high speed running state, the steering operation is more stable when the steering load is larger than that in the low speed running state. Therefore, in order to set the first and second communication passages a1, a2 and b1, b2 to the communication state in the high-speed traveling state, the left and right steering shaft drive units 410, 420 generate a reaction force in the direction opposite to the steering direction by the driver. generate. As a result, the driver's steering load during high-speed traveling increases, and the steering stability can be improved.

(7) (17) The left solenoid valve 100 and the right solenoid valve 200 variably control the flow passage cross sections of the first communication passages a1 and a2 and the second communication passages b1 and b2 according to the vehicle speed. It was.
By making the pressure introduced into the left and right steering shaft driving units 410 and 420 variable according to changes in the vehicle speed, a steering reaction force corresponding to the vehicle speed can be applied to the steering wheel SW.

(8) The back pressure solenoid valve 300 is an on / off valve.
The control configuration of the back pressure solenoid valve 300 and the control unit CU that drives the back pressure solenoid valve 300 can be simplified.

(9) (15) The back pressure solenoid valve 300 is configured to open in a non-energized state.
When the back pressure solenoid valve 300 fails and becomes non-energized, the third communication passages c1 and c2 are in a communication state, so that the rotary valve 600 and the reservoir tank 5 communicate with each other and the hydraulic pressure in the circuit is excessive. It will never be. Therefore, the load on the pump P can be reduced.

(11) The rotary valve 600 is
An inner valve portion 610 provided on the input shaft 4;
An outer valve portion 620 provided on the output shaft 6 so as to surround the inner valve portion 610;
The hydraulic fluid that is formed on the inner peripheral surface of the inner valve portion 610 and is supplied from the pump P by the relative rotation of the input shaft 4 and the output shaft 6 is selectively supplied to the right steering pressure chamber 21 and the left steering pressure chamber 22. Valve grooves 611 and 621 for switching oil passages;
A supply oil passage IN ′ formed in the outer valve portion 620 and supplying hydraulic fluid supplied from the pump P to the valve grooves 611 and 621;
Formed in the outer valve portion 620, and is constituted by a discharge oil passage OUT ′ for discharging the hydraulic fluid in the valve grooves 611 and 621 to the reservoir tank 5,
The back pressure solenoid valve 300 is provided between the drain oil passage OUT ′ and the reservoir tank 5.
The function and effect (1) can be obtained only by providing the back pressure solenoid valve 300 between the drain oil passage OUT ′ and the reservoir tank 5 which have been directly connected in the past.

(12) The third communication passages c1 and c2 further include a pressure sensor 6h that detects the pressure on the rotary valve 600 side relative to the back pressure solenoid valve 300,
When a command signal for closing the back pressure solenoid valve 300 is output to the back pressure solenoid valve 300 and the detected pressure of the pressure sensor 6h is equal to or lower than a predetermined value, an abnormality of the back pressure solenoid valve 300 is detected.
When the back pressure solenoid valve 300 does not close normally, the pressure detected by the pressure sensor 6h does not increase, so that an abnormality of the back pressure solenoid valve 300 can be detected.

(13) Environmental information detection devices 6a to 6g that detect vehicle, driver, or road information;
Based on the output signals of the environmental information detection devices 6a to 6g, when command signals are output to the left solenoid valve 100 and the right solenoid valve 200 and the left solenoid valve 100 or the right solenoid valve 200 is driven and controlled, The control unit CU for driving and controlling the back pressure solenoid valve 300 is provided so that the oil passage area of the three communication passages c1 and c2 is reduced.
The pressure in the hydraulic circuit is increased by reducing the oil passage area of the third communication passages c1 and c2 by the back pressure solenoid valve 300, and the torque applied to the steering wheel SW from the left and right steering shaft driving portions 410 and 420 is increased. Can be increased.

(14) The control unit CU detects any abnormality of the left solenoid valve 100, the right solenoid valve 200, the back pressure solenoid valve 300, the output signals from the environmental information detection devices 6a to 6g, and the control unit CU itself. When doing so, the back pressure solenoid valve 300 was opened.
When an abnormality in the apparatus is detected, the back pressure solenoid valve 300 is opened, so that the discharge pressure of the pump P is the back pressure solenoid even if the left and right solenoid valves 100 and 200 are opened. Since the liquid is discharged to the reservoir tank 5 through the valve 300, the hydraulic pressure of the steering shaft driving units 410 and 420 does not rise sufficiently.
Therefore, when an abnormality occurs in the apparatus, the steering assist can be continued without being affected by the steering shaft driving units 410 and 420.

(19) the housing 11;
An input shaft 4 connected to the steering wheel SW and rotatably accommodated in the housing 11;
An output shaft 6 rotatably accommodated in the housing 11 and connected to the input shaft 4 so as to be relatively rotatable;
A power cylinder having a right steering pressure chamber 21 and a left steering pressure chamber 22, and applying a steering force to the steered wheels by hydraulic fluid supplied to the right steering pressure chamber 21 and the left steering pressure chamber 22;
Provided in the housing 11, and a selectively supplying rotary valve 600 the hydraulic fluid supplied from the pump P by the relative rotation of the output shaft 6 and the input shaft 4 to the right steering pressure chamber 21 and the left steering pressure chamber 22 The configuration (1) is applied to the power steering device.
Accordingly, even in the power steering apparatus of the above formats, it is possible to obtain the same effects as the above (1).

Example 2 will be described. The basic configuration is the same as that of the first embodiment. In the first embodiment, the initial abnormality determination is performed regardless of whether or not the solenoid valves 100 to 300 are requested to be driven (see FIG. 23). In the second embodiment, the initial abnormality determination is performed only when there is no control request for the solenoid valves 100 to 300. It differs in that it performs.

  FIG. 27 adds step S101a when performing the initial abnormality determination flow of the first embodiment, and determines whether or not there is a control request for the solenoid valves 100 to 300. If there is a control request, the control is terminated, and if not, the initial abnormality determination similar to that in the first embodiment is performed. Thereby, when there is no control request, the initial abnormality determination can be performed, and the abnormality detection accuracy can be improved.

  Example 3 will be described. In the third embodiment, control when only the back pressure solenoid valve 300 has failed will be described. In the SSPS control mode, the back pressure solenoid valve 300 is in an open state (non-energized state), so the SSPS control mode is executed even when the third solenoid SOL3 provided in the back pressure solenoid valve 300 fails. Is.

FIG. 28 is an abnormality determination flow in the third embodiment. The following steps S201a and S201b are added to the abnormality determination flow of the first embodiment (see FIG. 24).
(Step S201a)
An abnormality flag of the third solenoid SOL3 in the back pressure solenoid valve 300 is determined.
(Step S201b)
In step S201b, since the back pressure solenoid valve 300 has failed, energization of the first and second solenoids SOL1, SOL2 provided in the left and right direction solenoid valves 100, 200 is permitted, and the back pressure solenoid valve 300 is turned on. The SSPS control mode is executed with the energization permission amount of the provided third solenoid SOL3 as 0. Thus, the SSPS control mode can be executed even when the back pressure solenoid valve 300 has failed.

  Example 4 will be described. In the first embodiment, the back pressure solenoid valve 300 is an on / off valve, but in the fourth embodiment, it is a proportional valve.

  FIG. 29 changes step S304 in the energization amount command value setting flow of the first embodiment (see FIG. 25) to S304a. As the back pressure solenoid valve 300 is a proportional valve, the energization amount command value of the third solenoid SOL3 of the back pressure solenoid valve 300 is variably controlled. Others are the same as FIG.

  When the left and right steering shaft driving units 410 and 420 are not driven, such as during normal steering assist, the driving amount of the pump P is reduced by reducing or reducing the throttle amount of the back pressure solenoid valve 300 that is a proportional valve. Can be reduced.

(10) (18) The first, second and back pressure solenoid valves 300 are proportional valves,
The back pressure solenoid valve 300 variably controls the flow passage areas of the third communication passages c1 and c2 in accordance with the pressure required for the left steering shaft driving unit 410 and the right steering shaft driving unit 420.
By controlling the valve opening amount of the back pressure solenoid valve 300 in accordance with the required pressure, the hydraulic pressure in the circuit can be appropriately controlled as compared with the case where the valve opening amount of the back pressure solenoid valve 300 is constant. . Therefore, the hydraulic pressure in the circuit does not become excessive, and the load on the pump P can be reduced.

[Other embodiments]
The best mode for carrying out the present invention has been described based on the embodiments. However, the specific configuration of the present invention is not limited to each embodiment, and the scope of the invention is not deviated. Design changes and the like are included in the present invention.

1 is a system configuration diagram of a power steering apparatus 1 of the present application. It is a hydraulic circuit diagram of a power steering device. It is an axial sectional view of a power steering device. It is an external view of a power steering device (y-axis positive direction front view). It is an external view of a power steering device (a z-axis negative direction front view). FIG. 5 is an enlarged view of the vicinity of a back pressure solenoid valve in FIG. 4. It is an axial sectional view of an input / output shaft. It is an enlarged view of an inner valve outer periphery. It is II sectional drawing of FIG. 7, FIG. It is sectional drawing of the left direction solenoid valve vicinity. It is sectional drawing of the right direction solenoid valve vicinity. It is sectional drawing of the solenoid valve for back pressure. It is the II-II cross section of FIG. It is the III-III cross section of FIG. FIG. 3 is a hydraulic circuit diagram during normal steering assist (left steering assist state). FIG. 3 is a hydraulic circuit diagram during normal steering assist (right steering assist state). It is a hydraulic circuit in an automatic steering preparation state. It is a hydraulic circuit in the left-turn automatic steering state. It is a hydraulic circuit in a right turn automatic steering state. It is a hydraulic circuit diagram at the time of steering reaction force control (SSPS mode) (right direction reaction force provision). It is a hydraulic circuit diagram at the time of steering reaction force control (SSPS mode) (left direction reaction force provision). It is the main flow of this application. It is an initial abnormality determination flow. It is an abnormality determination flow. It is an energization amount command value setting flow. It is an energization drive flow. It is an initial stage abnormality determination flow in Example 2. It is an abnormality determination flow in Example 3. It is an energization amount command value setting flow in the fourth embodiment.

Explanation of symbols

4 Input shaft 5 Reservoir tank 6 Output shafts 6a to 6g Environmental information detection device 11 Housing 21 Right steering pressure chamber (first pressure chamber)
22 Left steering pressure chamber (second pressure chamber)
30 Sector shaft (transmission mechanism)
60a Ball screw mechanism (conversion mechanism)
70 Piston 100 Left solenoid valve (first solenoid valve)
200 Right solenoid valve (second solenoid valve)
300 Back pressure solenoid valve (3rd solenoid valve)
410 Left-hand steering shaft drive unit (first reaction force control mechanism)
420 Right steering shaft drive (second reaction force control mechanism)
500 Fixed orifice 600 Rotary valve 610 Inner valve part 620 Outer valve part 611, 621 Valve groove (valve part)
a1, a2 First communication path b1, b2 Second communication path c1, c2 Third communication path B Power supply CU Control unit (control circuit)
IN 'Supply oil path OUT' Drain oil path P Pump SW Steering wheel

Claims (20)

A housing;
An input shaft connected to a steering wheel and rotatably accommodated with respect to the housing;
An output shaft that is rotatably accommodated with respect to the housing, and is connected to the input shaft so as to be relatively rotatable;
A piston housed in the housing and separating the interior of the housing into a first pressure chamber and a second pressure chamber;
A rotary valve provided in the housing and selectively supplying hydraulic oil supplied from a pump by relative rotation of the input shaft and the output shaft to the first pressure chamber and the second pressure chamber;
A conversion mechanism that converts rotation of the output shaft into axial movement of the piston;
A transmission mechanism for transmitting the axial movement of the piston to the steering wheel;
A first steering shaft driving unit that is connected to the rotary valve and applies a rotational force in a clockwise direction to the steering wheel;
A second steering shaft drive unit that is connected to the rotary valve and applies a counterclockwise rotational force to the steering wheel;
Provided in the first communication passage on which communicates with the rotary valve and the first steering shaft driving unit, a first solenoid valve for controlling switching and blocking communication of said first communication path,
Provided on the second communication passage for communicating the said rotary valve and the second steering shaft driving unit, and a second solenoid valve for controlling switching and blocking communication of said second communication path,
Wherein a reservoir tank for storing the created aggressive media provided on the third communication passage which connects the rotary valve, a third solenoid valve which controls switching and blocking communication of said third communication passage,
Information signal traveling state or a driver's driving state of the vehicle is inputted, the first solenoid valve, possess the second solenoid valve, and a control circuit for driving and controlling the third solenoid valve,
The first steering shaft drive unit is driven by the pressure of hydraulic oil supplied through the first communication path when the first solenoid valve is opened, and exerts a rotational force in a clockwise direction on the steering wheel. Grant,
The second steering shaft driving unit is driven by the pressure of hydraulic oil supplied through the second communication passage when the second solenoid valve is opened, and the counterclockwise rotational force is applied to the steering wheel. And grant
The control circuit determines whether to apply a clockwise rotational force or a counterclockwise rotational force to the steering wheel based on the information signal of the running state or the driving state, Based on the result of the determination, a valve opening command signal is output to the first solenoid valve or the second solenoid valve, and a command signal is output to the third solenoid valve, and the first communication path and the first solenoid valve are output. The oil passage area of the third communication passage is reduced so that the pressure in the hydraulic circuit including the two communication passages is increased, and the outflow of hydraulic oil from the hydraulic circuit to the reservoir tank is suppressed. Steering control device. The steering control device according to claim 1, wherein
The steering control device, wherein the first solenoid valve and the second solenoid valve are configured to close in a non-energized state. The steering control device according to claim 1, wherein
The first, second and third solenoid valves and the control circuit are supplied with power from a power source,
When the control circuit detects any abnormality of the first, second, and third solenoid valves, the information signal input to the control circuit, the power source, and the control circuit itself, the first, A steering control device characterized by controlling all of the second and third solenoid valves to be in a non-energized state. The steering control device according to claim 1, wherein
It further includes a fixed orifice that maintains a constant flow area,
The steering control device, wherein the fixed orifice is provided in parallel with the third solenoid valve and on a flow path connecting the reservoir tank and the rotary valve. The steering control device according to claim 4, wherein
The rotary valve is
An inner valve portion provided on the input shaft;
An outer valve portion provided on the output shaft so as to surround the inner valve portion;
Formed on the outer peripheral surface of the inner valve portion and the inner peripheral surface of the outer valve portion, hydraulic oil supplied from the pump is supplied to the first pressure chamber and the second pressure chamber by relative rotation of the input shaft and the output shaft. A valve section for switching the oil passage so as to be selectively supplied to
A supply oil passage formed in the outer valve portion and supplying hydraulic oil supplied from the pump to the valve portion;
A drain oil passage formed in the outer valve portion and discharging the hydraulic oil in the valve portion to the reservoir tank;
The fixed orifice is an outer peripheral surface of the inner valve portion and is provided closer to the input shaft than the valve portion, and a circumferential interval of the inner valve portion is formed so as to form a gap with the outer valve portion. It is constituted by a small diameter part formed over a predetermined range,
The steering control device according to claim 1, wherein the drain oil passage is configured to communicate with the fixed orifice through a gap between the inner valve portion and the outer valve portion. The steering control device according to claim 1, wherein
The rotary valve is
When the steering wheel is steered counterclockwise, supply more hydraulic oil from the pump to the first pressure chamber than to the second pressure chamber;
When the steering wheel is steered clockwise, it is configured to supply more hydraulic oil from the pump to the second pressure chamber than to the first pressure chamber,
When the first solenoid valve is opened and the pressure of the first pressure chamber is supplied to the first steering shaft driving unit, the first steering shaft driving unit rotates the steering wheel clockwise. Giving a rotational force,
When the second solenoid valve is opened and the pressure of the second pressure chamber is supplied to the second steering shaft drive unit, the second steering shaft drive unit rotates counterclockwise to the steering wheel. The rotational force of
When the vehicle speed is higher than the specified value,
The third solenoid valve is driven and controlled so that the oil passage area of the third communication passage is maximized,
The first solenoid valve is drive-controlled so that the first communication path is in a communication state,
The steering control device, wherein the second solenoid valve is driven and controlled so that the second communication path is in a communication state. The steering control device according to claim 6, wherein
The steering control device according to claim 1, wherein the first solenoid valve and the second solenoid valve variably control flow passage cross-sectional areas of the first communication path and the second communication path according to a vehicle speed. The steering control device according to claim 1, wherein
The steering control device, wherein the third solenoid valve is an on / off valve. The steering control device according to claim 1, wherein
The third solenoid valve is configured to open in a non-energized state. The steering control device according to claim 1, wherein
The first, second and third solenoid valves are proportional valves,
The third solenoid valve variably controls an oil passage area of the third communication path according to a pressure required for the first steering shaft driving unit and the second steering shaft driving unit. . The steering control device according to claim 1, wherein
The rotary valve is
An inner valve portion provided on the input shaft;
An outer valve portion provided on the output shaft so as to surround the inner valve portion;
An oil passage is switched to selectively supply hydraulic oil supplied from the pump to the first pressure chamber and the second pressure chamber by the relative rotation of the input shaft and the output shaft, which is formed in the inner valve portion. A valve section;
A supply oil passage formed in the outer valve portion and supplying hydraulic oil supplied from the pump to the valve portion;
A drain oil passage formed in the outer valve portion and discharging the hydraulic oil in the valve portion to the reservoir tank;
The steering control device, wherein the third solenoid valve is provided between the drain oil passage and the reservoir tank. The steering control device according to claim 1, wherein
A pressure sensor for detecting the pressure on the rotary valve side of the third solenoid valve in the third communication path;
An abnormality of the third solenoid valve is detected when a command signal for closing the third solenoid valve is output to the third solenoid valve and the detected pressure of the pressure sensor is a predetermined value or less. Steering control device. A housing;
An input shaft connected to the steering wheel and rotatably accommodated in the housing;
An output shaft housed in the housing and connected to the input shaft so as to be relatively rotatable;
A piston housed in the housing and separating the interior of the housing into a first pressure chamber and a second pressure chamber;
A rotary valve provided in the housing and selectively supplying hydraulic fluid supplied from a pump by relative rotation of the input shaft and the output shaft to the first pressure chamber and the second pressure chamber;
A conversion mechanism that converts rotation of the output shaft into axial movement of the piston;
A transmission mechanism for transmitting the axial movement of the piston to the steering wheel;
A first steering shaft driving unit that is connected to the rotary valve and applies a rotational force in a clockwise direction to the steering wheel;
A second steering shaft drive unit that is connected to the rotary valve and applies a counterclockwise rotational force to the steering wheel;
A first solenoid valve that is provided on a first communication path that communicates the rotary valve and the first steering shaft drive unit, and controls switching between communication and blocking of the first communication path;
A second solenoid valve that is provided on a second communication path that communicates the rotary valve and the second steering shaft drive unit, and controls switching between communication and blocking of the second communication path;
A third solenoid valve provided in the third communication passage on which connects the rotary valve and a reservoir tank for storing the work moving fluid,
An environmental information detection device that detects vehicle, driver, or road information;
The output signal of the environmental information detection apparatus is inputted, the first solenoid valve, possess the second solenoid valve, and a control circuit for driving and controlling the third solenoid valve,
The first steering shaft driving unit is driven by the pressure of the first pressure chamber supplied through the first communication passage when the first solenoid valve is opened, and is clockwise with respect to the steering wheel. The rotational force of
The second steering shaft drive unit is driven by the pressure of the second pressure chamber supplied via the second communication passage when the second solenoid valve is opened, and rotates counterclockwise with respect to the steering wheel. To give direction rotational force,
The control circuit determines whether to apply a clockwise rotational force or a counterclockwise rotational force to the steering wheel based on an output signal of the environmental information detection device, and the determination Based on the result of the above, a valve opening command signal is output to the first solenoid valve or the second solenoid valve, and a command signal is output to the third solenoid valve, so that the flow area of the third communication path is increased. By reducing the flow rate, the outflow of hydraulic fluid from the hydraulic circuit including the first communication path and the second communication path to the reservoir tank is suppressed.
A steering control device characterized by that. The steering control device according to claim 13,
When the control circuit detects an abnormality in any of the first solenoid valve, the second solenoid valve, the third solenoid valve, an output signal from the environmental information detection device, and the control circuit itself, A steering control device characterized by opening three solenoid valves. The steering control device according to claim 14, wherein
The steering control device, wherein the third solenoid valve is configured to be opened in a non-energized state. The steering control device according to claim 13,
The rotary valve is
When the steering wheel is steered counterclockwise, supply more hydraulic fluid from the pump to the first pressure chamber than to the second pressure chamber;
When the steering wheel is steered clockwise, supply more hydraulic fluid from the pump to the second pressure chamber than to the first pressure chamber ;
The control circuit includes:
When the vehicle speed is higher than a predetermined value, the third solenoid valve is driven and controlled so that the flow passage area of the third communication path is maximized,
Driving and controlling the first solenoid valve so that the first communication path is in a communication state;
The steering control device, wherein the second solenoid valve is drive-controlled so that the second communication path is in a communication state. The steering control device according to claim 16, wherein
The control circuit controls each of the first solenoid valve and the second solenoid valve so that flow path cross-sectional areas of the first communication path and the second communication path change according to a vehicle speed. A steering control device characterized by the above. The steering control device according to claim 13,
The first, second and third solenoid valves are proportional valves,
The control circuit controls the third solenoid valve so that a flow area of the third communication path changes according to a pressure required for the first steering shaft driving unit and the second steering shaft driving unit. A steering control device characterized by that. A housing;
An input shaft connected to the steering wheel and rotatably accommodated in the housing;
An output shaft rotatably accommodated in the housing and connected to the input shaft so as to be relatively rotatable;
A power cylinder having a first pressure chamber and a second pressure chamber, and applying a steering force to the steered wheels by hydraulic oil supplied to the first pressure chamber and the second pressure chamber;
Provided in the housing, selectively supplying rotary valve the hydraulic oil supplied from the pump by the relative rotation of the output shaft and the input shaft to the second pressure chamber and the first pressure chamber,
A first steering shaft drive unit that is connected to the rotary valve and applies a rotational force to the steering wheel;
A second steering shaft drive unit that is connected to the rotary valve and applies a rotational force in a direction opposite to the first steering shaft drive unit to the steering wheel;
Provided in the first communication passage on which communicates with the rotary valve and the first steering shaft driving unit, a first solenoid valve for controlling switching and blocking communication of said first communication path,
Provided on the second communication passage for communicating the said rotary valve and the second steering shaft driving unit, and a second solenoid valve for controlling switching and blocking communication of said second communication path,
Wherein a reservoir tank for storing the created aggressive media provided on the third communication passage which connects the rotary valve, a third solenoid valve which controls switching and blocking communication of said third communication passage,
A control circuit for driving and controlling the first solenoid valve, the second solenoid valve, and the third solenoid valve, when an information signal of a vehicle running state or a driver driving state is input;
I have a,
The first steering shaft drive unit is driven by the pressure of hydraulic oil supplied through the first communication path when the first solenoid valve is opened, and applies a rotational force to the steering wheel.
The second steering shaft driving unit is driven by the pressure of hydraulic oil supplied through the second communication passage when the second solenoid valve is opened, and the first steering shaft driving unit is driven with respect to the steering wheel. Giving a rotational force in the opposite direction,
The control circuit outputs a valve opening command signal to the first solenoid valve or the second solenoid valve and outputs a command signal to the third solenoid valve based on the information signal of the running state or the driving state. The hydraulic fluid is output and the oil passage area of the third communication passage is reduced, thereby suppressing the outflow of hydraulic oil from the hydraulic circuit including the first communication passage and the second communication passage to the reservoir tank.
A steering control device characterized by that. The steering control device according to claim 19,
Said first solenoid valve and the second solenoid valve, the steering control apparatus characterized by being configured to close valve in the non-energized state.

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