JP6663331B2 - Power steering device - Google Patents

Description

  The present invention relates to a power steering device.

  2. Description of the Related Art As a conventional power steering device, for example, a device described in Patent Document 1 below is known.

  This power steering device includes a first pump driven by an engine and a second pump driven by an electric motor. Normally, steering is assisted by supplying hydraulic pressure to the steering mechanism using only the first pump or both the first and second pumps. When the supply of hydraulic pressure by the first pump cannot be expected, for example, when the first pump fails, the steering assist is continued by driving the second pump.

JP 2013-018379 A

  Meanwhile, in recent years, in order to enable automatic driving, a technique has been devised in which a steering motor for providing a steering assist force is attached to a steering device of the conventional power steering device. In such a case, it is conceivable that the steering motor is also driven when the first pump fails and the steering assist is continued by cooperation of the second pump and the steering motor. Does not describe a steering motor, and naturally does not consider a steering motor.

  The present invention has been devised in view of the conventional situation, and a power steering device capable of suppressing an increase in a driver's steering load by cooperation of a second pump and a steering motor even when a first pump is stopped. It is intended to provide.

  The present invention provides a steering mechanism, a power cylinder that applies a steering assist force to the steering mechanism, a first pump that is driven by an engine and discharges a hydraulic fluid, and a hydraulic pump that is driven by a pump driving motor. A second pump for discharging, a rotary valve for selectively supplying hydraulic fluid supplied from the first pump or the second pump to a pair of hydraulic chambers of the power cylinder, and an input shaft of the steering mechanism. A steering motor for applying a steering force, and a pump drive motor control unit that is provided in the control device and that drives the pump drive motor when at least the first pump is in a stopped state; and A steering motor control unit that drives the steering motor when at least the first pump is in a stopped state.

  According to the present invention, even when the first pump is stopped, an increase in the driver's steering load can be suppressed by cooperation between the second pump and the steering motor.

1 is a schematic diagram showing a power steering device according to the present invention. It is a longitudinal section of a power steering device main part concerning the present invention. FIG. 3 is a view as viewed in the direction of arrow A in FIG. 2, showing a steering motor removed. FIG. 4 is a hydraulic circuit diagram when the first pump is operating. FIG. 4 is a hydraulic circuit diagram when the first pump is stopped. FIG. 3 is a control block diagram illustrating an arithmetic circuit configuration of the control device. It is a figure which shows the relationship between a steering torque and the steering assist force which a steering motor outputs. FIG. 4 is a diagram illustrating a relationship between a steering torque and a rotation speed of a pump driving motor. 4 is a flowchart illustrating a series of flow of drive control processing of a steering motor and a pump drive motor by a control device. FIG. 9 is a control block diagram illustrating an arithmetic circuit configuration of a control device according to a second embodiment of the present invention. FIG. 4 is a diagram illustrating a relationship between a steering torque and a motor drive current for driving a second pump. It is a figure which shows the relationship between a steering speed and the rotation speed of a 2nd pump. It is a figure which shows the relationship between a steering speed and the rotation speed of a 2nd pump. It is a figure showing details of control of the number of rotations of the 2nd pump concerning a 3rd embodiment of the present invention.

  Hereinafter, an embodiment of a power steering device according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic diagram showing a configuration of a power steering device according to a first embodiment of the present invention and a hydraulic circuit applied to the power steering device.

  The power steering apparatus according to the present embodiment amplifies a steering force input to a steering wheel (not shown) by a first power cylinder C1 (see FIG. 2) and a steering motor M1, which will be described later. A power steering device body 10 that assists the driver's steering operation by transmitting the signal to the outside first steered wheels, and a power steering device body 10 that is provided separately from the first steered wheels and that is different from the first steered wheels. A second power cylinder C2 for steering the two steered wheels, and a main pump driven by the engine E of the vehicle and supplying oil as hydraulic fluid to the power cylinders C1 and C2 via a rotary valve 13 described later. Is driven by a first pump P1 and a pump driving motor M2, which is an electric motor, and supplies oil to each power through a rotary valve 13. A second pump P2 as a sub-pump to be supplied to the cylinders C1 and C2, a reservoir tank T for storing oil to be supplied to each of the power cylinders C1 and C2, and drive control of a pump drive motor M2 and a steering motor M1 And a control device 70 provided for

  The reservoir tank T is partitioned into a first storage part T1 and a second storage part T2 by a partition wall TW provided to extend upward in the direction of gravity from the bottom wall. The first storage part T1 is mainly used for storing the oil sucked and discharged by the first pump P1, while the second storage part T2 is mainly used for storing the oil sucked and discharged by the second pump P2. . In addition, when the liquid level of the oil stored in the reservoir tank T is higher than the height of the partition wall TW, the first and second storage units T1 and T2 share the oil with each other, and When the surface is lower than the height of the partition wall TW, the oil is held independently. The liquid level of the oil is detected by a liquid amount sensor 71 disposed at a position substantially equal to the height of the partition wall TW on the peripheral wall of the reservoir tank T.

  The control device 70 is configured to include an electronic component such as a microcomputer, and is turned on by receiving an ignition-on signal (IGN signal) from an ignition switch.

  The control device 70 receives a steering angle signal θs from a later-described first resolver 55 provided in the power steering device main body 10, and receives a steering motor rotation angle signal from a later-described second resolver 62 also provided in the power steering device main body 10. θm1 is input. Further, the control device 70 receives a pump drive motor rotation angle signal θm2 from a pump drive motor rotation angle sensor (not shown) attached to the pump drive motor M2. Further, the control device 70 receives an oil level signal OL indicating the height of the oil level from the liquid amount sensor 71, and is provided in a first supply passage F1 described later, and is connected to the rotary valve 13 from the first pump P1. A hydraulic pressure signal OP indicating the level of the supply hydraulic pressure is input from a pressure sensor 72 that detects a supply hydraulic pressure (supply hydraulic pressure) of the supplied oil. Then, based on these various signals, the control device 70 performs various control processes including drive control of the pump driving motor M2 and the steering motor M1.

  FIG. 2 is a longitudinal sectional view showing a specific configuration of the power steering device main body 10.

  The power steering apparatus main body 10 includes a so-called integral type hydraulic power steering apparatus equipped with the above-described steering motor M1 to perform steering assist control and automatic operation control by cooperation between hydraulic pressure (oil pressure) and motor torque. And so on.

  That is, the power steering device main body 10 includes a steering mechanism 11 that steers the first steered wheels in accordance with a steering operation of a steering wheel (not shown), a housing 12 that accommodates a part of the steering mechanism 11 therein, and a housing 12. Of the first power cylinder C1 and the rotary valve 13 and the connection between the first and second pumps P1 and P2 and the rotary valve 13, and the first and second storage portions T1 of the rotary valve 13 and the reservoir tank T , T2, a switching valve 14 (see FIG. 4) for switching the connection between the rotary valve 13 and the second power cylinder C2, and a housing 12 of the steering mechanism 11. And a steering motor M1 attached to the exposed portion.

  One end of the steering mechanism 11 faces the outside of the housing 12 and is connected to the steering wheel. The other end of the steering mechanism 11 is connected to the steering shaft 16 housed in the housing 12 and the other end of the steering shaft 16. A transmission mechanism 17 for transmitting rotation to the first steered wheels.

  One end of the steering shaft 16 is connected to the steering wheel so as to be integrally rotatable, and the other end of the input shaft 18 is connected to a first torsion bar 20 (corresponding to a torsion bar according to the present invention) at one end. And an output shaft 19 connected to the output shaft 19 so as to be relatively rotatable.

  The input shaft 18 has a first input shaft 21 at one end directly connected to the steering wheel, and a first input shaft 21 at the other end rotatably connected to the first input shaft 21 via a second torsion bar 23. And a second input shaft 22. The first input shaft 21 is formed in a hollow shape and accommodates most of the second torsion bar 23 inside. The first input shaft 21 has an opening formed at the other end to have a smaller diameter than the one end at the steering wheel side and the other end formed at one end of the second input shaft 22 at the steering wheel side. It is housed in the recess 22a. Further, two needle bearings 24, 24 are provided between the outer peripheral surface of the other end of the first input shaft 21 and the inner peripheral surface of the open recess 22a of the second input shaft 22. The first input shaft 21 is rotatably supported by the second input shaft 22 via the needle bearings 24, 24.

  The output shaft 19 is formed in a hollow shape and accommodates most of the first torsion bar 20 therein. The output shaft 19 has one end on the input shaft 18 side with a larger diameter than the other end, and houses the other end of the second input shaft 22 inside the one end.

  The first torsion bar 20 has a function of changing a flow path and a flow path cross-sectional area of the rotary valve 13 described later according to the twist direction and the twist angle. On the other hand, the second torsion bar 23 is configured as a torsion bar for a torque sensor 78 (see FIG. 6) not shown in FIG. 2, and the torque sensor 78 performs steering according to the amount of twist of the second torsion bar 23. The torque is detected.

  The transmission mechanism 17 converts a steering force (rotational force) input to the output shaft 19 into a movement force in the rotation axis X direction of the steering shaft 16, and a movement force converted by the ball screw mechanism 25. And a sector shaft 26 that rotates based on the rotation.

  The ball screw mechanism 25 includes an output shaft 19 as a screw shaft having a spirally formed ball groove 25a formed on the outer circumference, and a ball groove 25b disposed on the outer circumference side of the output shaft 19 and corresponding to the ball groove 25a on the inner circumference. And a plurality of balls 25c housed in both ball grooves 25a and 25b. The piston 29 has a tooth portion 29a at a portion facing the sector shaft 26 on the outer periphery.

  The sector shaft 26 is disposed so as to be substantially perpendicular to the rotation axis X of the steering shaft 16. The sector shaft 26 has a tooth portion 26a which can be engaged with the tooth portion 29a of the piston 29 on the outer periphery of one end in the axial direction, and a pitman (not shown) which is a part of a transmission mechanism at the other end. The arm is connected. The pitman arm is adapted to appropriately change the direction of the first steered wheels by being pulled in the width direction of the vehicle body as the sector shaft 26 rotates.

  The housing 12 includes a first housing 27 that is open at one end on the steering wheel side, a second housing 28 that is provided so as to close one end of the first housing 27, and that accommodates a rotary valve 13 described below, It has. The first housing 27 and the second housing 28 are fastened to each other with a plurality of bolts (not shown) arranged at predetermined positions in the circumferential direction with respect to the rotation axis X of the steering shaft 16.

  The first housing 27 is formed along the rotation axis X direction of the steering shaft 16, and has a substantially cylindrical cylinder portion 27 a in which a piston 29 is housed. The first housing 27 is substantially orthogonal to the cylinder portion 27 a and partially has a cylinder shape. And a shaft accommodating portion 27b formed so as to face the portion 27a and accommodating the sector shaft 26 therein.

  The first power cylinder C1 includes a cylinder portion 27a of the first housing 27 and a piston 29 housed inside the cylinder portion 27a.

  The piston 29 has a bobbin shape, and one end 29b closer to the steering wheel and the other end 29c farther from the steering wheel in the direction of the rotation axis X have outer diameters slightly smaller than the inner diameter of the cylinder 27a. Have been. As a result, the piston 29 is maintained in a stable posture in the cylinder portion 27a. An annular seal member 29d is mounted on the outer periphery of the other end 29c of the piston 29. The seal member 29d divides the internal space of the cylinder portion 27a into a first hydraulic chamber X1 on the steering wheel side of the seal member 29d and a second hydraulic chamber X2 on a side separated from the steering wheel. Have been. That is, the first power cylinder C1 has the first and second hydraulic chambers X1 and X2, which are a pair of hydraulic chambers partitioned by the piston 29 in the cylinder portion 27a.

  When oil is supplied to the first hydraulic chamber X1 or the second hydraulic chamber X2, the first power cylinder C1 uses a pressure difference between the two hydraulic chambers X1 and X2 as a steering assist force and serves as a piston that is also a part of the steering mechanism 11. 29. At this time, the oil in the first hydraulic chamber X1 is guided to the shaft accommodating portion 27b, and the space between the teeth 26a and 29a is lubricated when the oil is supplied to the first hydraulic chamber X1. It has become.

  The rotary valve 13 opens according to the amount of torsion of the first torsion bar 20 based on the relative rotation between the second input shaft 22 and the output shaft 19, and connects to the hydraulic chambers X1, X2, etc. of the first power cylinder C1. Supply or drain oil.

  Specifically, when the steering wheel is steered in any one direction, the rotary valve 13 supplies oil to the first hydraulic chamber X1 through the first communication passage 30 formed through the output shaft 19. The oil is discharged from the second hydraulic chamber X2 through a second communication passage 31 provided across the first and second housings 28. On the other hand, when the steering wheel is steered in the other direction, oil is supplied to the second hydraulic chamber X2 via the second communication path 31 and from the first hydraulic chamber X1 via the first communication path 30. It is designed to drain oil.

  FIG. 3 is a view on arrow A of FIG. 2 showing the steering motor M1 removed. In FIG. 3, a part of the portion related to the switching valve 14 and the cylinder switching valve 15 is shown in a partial cross section. Hereinafter, both valves 14 and 15 will be described in detail with reference to FIG.

  The switching valve 14 includes a valve body 32 having a valve body housing hole 33 that is open at one end in the longitudinal direction and is closed at the other end, a plug 34 that closes one end of the valve body housing hole 33, and a valve body housing hole. A spool-shaped valve body 35 movably accommodated in the axial direction of the port 33 and switching the communication state of each port described later with a land portion provided on the outer peripheral portion according to the axial position; A valve spring 36 is provided between the bottom of the housing hole 33 and the valve body 35 and constantly urges the valve body 35 toward the plug 34, and controls the oil pressure of the oil supplied from the first pump P 1. Switching operation is performed as pilot pressure.

  The valve body 32 is connected to the second housing 28 on the side of the rotary valve 13. As a result, the switching valve 14 is radially outward of the rotary valve 13 in the radial direction with respect to the rotation axis of the rotary valve 13 (because the rotation axis X is coaxial with the rotation axis X of the steering shaft 16). And arranged so as to overlap with the rotary valve 13 in the direction of the rotation axis X.

  Further, on the side of the valve body 32, a first pump connection port PC1 for introducing oil from the first pump P1 into the valve housing hole 33, and an oil from the second pump P2 inside the valve housing hole 33. A second pump connection port PC2 to be introduced into the rotary valve 13, an introduction port IP for introducing oil supplied from one or both of the first and second pumps P1 and P2 into the rotary valve 13 through an introduction oil passage 37, and a discharge port. A discharge port XP for guiding the oil discharged from the rotary valve 13 through the oil passage 38 into the valve housing hole 33, and the oil in the valve housing hole 33 flows back to the first storage portion T1 of the reservoir tank T. A first tank connection port TC1 and a second tank connection port TC2 for recirculating the oil in the valve body housing hole 33 to the second storage portion T2 of the reservoir tank T are formed to penetrate therethrough.

  Here, the introduction oil passage 37 and the discharge oil passage 38 will be described in detail. These two oil passages 37, 38 correspond to a pair of oil passages according to the present invention, and are respectively provided in the second housing. 28 is formed so as to extend along the radial direction of the rotation axis X. The two oil passages 37 and 38 are used to connect the first and second screws 39 a to 39 d for connecting the steering motor M <b> 1 to the second housing 28. 39a and 39b. In other words, the first screw 39a is disposed on one side of both the oil passages 37 and 38 in the direction around the rotation axis X, and the second screw 39b is disposed on one side of the oil passages 37 and 38 in the direction around the rotation axis X. 38 on the other side.

  Similarly to the switching valve 14, the cylinder switching valve 15 also has a valve body 40 that has a valve body receiving hole 41 that is open at one end in the longitudinal direction and is closed at the other end, and closes one end of the valve body receiving hole 41. A spool 42 which is movably accommodated in the axial direction in the plug 42 and the valve body accommodating hole 41 and switches the communication state of each port described later with a land portion provided on the outer peripheral portion according to the axial position. And a valve spring 44 provided between the bottom of the valve body receiving hole 41 and the valve body 43 and constantly biasing the valve body 43 toward the plug 42. The first pump P1 The switching operation is performed using the oil pressure of the oil supplied from the controller as the pilot pressure.

  The valve body 40 is connected to the second housing 28 on the side of the rotary valve 13, similarly to the valve body 32 of the switching valve 14. Accordingly, the cylinder switching valve 15 is also arranged radially outside the rotary valve 13 in the radial direction with respect to the rotation axis X, and overlaps with the rotary valve 13 in the rotation axis X direction. .

  Also, on the side of the valve body 40, two first and second valve connection ports BC1 and BC2 connected to the rotary valve 13, and a pair of first and second hydraulic chambers of the second power cylinder C2. Of the second hydraulic chambers Y1 and Y2 (see FIGS. 1 and 4), a first cylinder connection port CC1 connected to the first hydraulic chamber Y1 and a second cylinder chamber connected to the second hydraulic chamber Y2 of the second power cylinder C2. The two-cylinder connection port CC2 is formed to penetrate therethrough.

  With the above-described configuration, the steering assist by the hydraulic pressure according to the present embodiment is performed according to the hydraulic circuit as shown in FIG. 4 or FIG. 5, depending on the operation state of the first pump P1.

  FIG. 4 is a hydraulic circuit diagram when the first pump P1 is operating.

  That is, in this state, since the oil pressure of the oil supplied by the first pump P1 acts on the switching valve 14 as pilot pressure, the valve body 35 is connected to the plug 34 against the spring force of the valve spring 36 based on this oil pressure. Move to the first position on the opposite side.

  Then, since the first and second pump connection ports PC1 and PC2 are connected to the introduction port IP, only the first pump P1 or both the first and second pumps P1 and P2 are selected depending on the operation state. Is supplied to the rotary valve 13 through the first and second supply passages F1 and F2 and the switching valve 14. Then, according to the opening state of the rotary valve 13 based on the steering operation, oil is supplied from the rotary valve 13 to one of the hydraulic chambers X1 and X2 of the first power cylinder C1, while the other is supplied. Oil is discharged from the pressure chamber. Here, in the switching valve 14, when the valve body 35 is at the first position, the discharge port XP is connected to the first tank connection port TC1. Therefore, all of the oil discharged from the first power cylinder C1 is returned to the first storage portion T1 of the reservoir tank T through the first circulation passage R1 while passing through the first tank connection port TC1. .

  When the first pump P1 is operating, the hydraulic pressure of the oil supplied by the first pump P1 also acts as a pilot pressure on the cylinder switching valve 15, so that the cylinder switching valve 15 is also operated based on this hydraulic pressure. The valve element 43 moves to the first position opposite to the plug 42 against the spring force of the valve spring 44.

  Then, the first valve connection port BC1 is connected to the first cylinder connection port CC1, and the second valve connection port BC2 is connected to the second cylinder connection port CC2. Thereby, according to the opening state of the rotary valve 13 based on the steering operation, oil is supplied from the rotary valve 13 to one of the hydraulic chambers Y1 and Y2 of the second power cylinder C2, while the other is supplied. The oil is discharged from the pressure chamber and is returned to the first storage portion T1 of the reservoir tank T.

  FIG. 5 is a hydraulic circuit diagram when the first pump P1 is stopped.

  That is, in this state, no oil is supplied from the first pump P1 to the switching valve 14, and the valve body 35 moves to the second position on the plug 34 side by the spring force of the valve spring 36.

  Then, while the communication between the first pump connection port PC1 and the introduction port IP is cut off, the state where the second pump connection port PC2 and the introduction port IP are connected is maintained. Therefore, only the oil discharged by the second pump P2 is supplied to the rotary valve 13 through the second supply passage F1 and the switching valve 14. Then, according to the opening state of the rotary valve 13 based on the steering operation, oil is supplied from the rotary valve 13 to one of the hydraulic chambers X1 and X2 of the first power cylinder C1, while the other is supplied. Oil is discharged from the pressure chamber. Here, in the switching valve 14, since the valve body 35 is at the second position, the discharge port XP is connected to the second tank connection port TC2. Therefore, all of the oil discharged from the first power cylinder C1 is returned to the second storage portion T2 of the reservoir tank T through the second circulation passage R2 while passing through the second tank connection port TC2. .

  When the first pump P1 is stopped, no pilot pressure is applied to the cylinder switching valve 15, so that the valve body 43 moves to the second position on the plug 42 side against the spring force of the valve spring 44. Will move.

  Then, the communication between the first valve connection port BC1 and the first cylinder connection port CC1 is cut off, and the communication between the second valve connection port BC2 and the second cylinder connection port CC2 is also cut off. The communication with the hydraulic chambers Y1 and Y2 of the second power cylinder C2 is cut off. That is, when the first pump P1 is stopped, the second power cylinder C2 does not operate, and the steering assist by the second power cylinder C2 is not performed.

  Referring back to FIG. 2, the steering motor M1 is a hollow motor provided so as to surround the input shaft 18 and a so-called three-phase AC brushless motor, which is used to generate a steering assist force. And a motor housing 45 accommodating the motor element therein.

  The motor element includes a cylindrical motor rotor 46 fixed to the second input shaft 22 via a coupling member 48 so as to be integrally rotatable, and a cylindrical motor stator disposed on the outer peripheral side of the motor rotor 46 with a predetermined gap therebetween. 47.

  The motor housing 45 is opened toward the housing 12 side, and has a first motor housing component 49 having a closed cylindrical shape that accommodates the motor element therein, and a disc that closes the opening of the first motor housing component 49. And a second motor housing component 50 in the shape of a letter. These first and second motor housing components 49 and 50 are both made of a predetermined metal material such as an aluminum alloy.

  The first motor housing component 49 is formed such that the inner diameter of the cylindrical portion 49a is substantially the same as the outer diameter of the motor stator 47, and the motor stator 47 is fixed to the inner periphery by press fitting, shrink fitting, or the like.

  The first motor housing component 49 has a flange 49b on the outer peripheral side of the opening, and the flange 49b is fastened and fixed to the disk-shaped adapter member 51 by bolts 52. Here, the adapter member 51 is also fastened and fixed to the second housing 28 of the housing 12 by a bolt 53. Therefore, the first motor housing component 49 is fixed to the second housing 28 via the adapter member 51.

  An insertion hole into which the coupling member 48 (the steering shaft 16) is inserted is formed in the lid portion 49c of the first motor housing component 49, and an inner peripheral surface of the insertion hole and an outer peripheral surface of the coupling member 48 are formed. A first ball bearing 54 is provided between them.

  Further, a first resolver 55 is disposed at a position closer to the steering wheel than the cover 49c.

  The first resolver 55 includes an annular resolver rotor 55a fixed to the outer periphery of the first input shaft 21 so as to be integrally rotatable, and an annular resolver stator 55b arranged at a predetermined gap on the outer periphery of the resolver rotor 55a. And The rotation angle of the first input shaft 21, that is, the steering angle of the steering wheel is detected by detecting the rotation position of the resolver rotor 55a by the resolver stator 55b. Note that the detected steering angle signal θs, which is a signal of the steering angle of the steering wheel, is transmitted to the control device 70 via the first sensor harness 56.

  The first resolver 55 is covered by a cover member 57. The cover member 57 is fastened and fixed to the first motor housing component 49 by bolts 58. Further, an insertion hole for inserting the first input shaft 21 is formed at an axial center position of the cover member 57, and the first input shaft 21 is provided between the insertion hole and the first input shaft 21. A second ball bearing 59 rotatably supported and a seal member 60 for sealing between the insertion hole and the first input shaft 21 are provided.

  The second motor housing constituent part 50 has an insertion hole for inserting the coupling member 48 (the steering shaft 16) at an axial position thereof, and the inner peripheral surface of the insertion hole and the outer peripheral surface of the coupling member 48 are connected to each other. A third ball bearing 61 is provided between them.

  Further, a second resolver 62 is disposed at a portion of the second motor housing component 50 on the housing 12 side. The second resolver 62 is disposed at a predetermined gap on the outer peripheral side of the resolver stator 62a and an annular resolver rotor 62a fixed to the outer periphery of the second input shaft 22 via the coupling member 48 so as to be integrally rotatable. And an annular resolver stator 62b. The rotation angle of the second input shaft 22 is detected by detecting the rotation position of the resolver rotor 62a by the resolver stator 62b. The rotation angle of the second input shaft 22 is equal to the rotation angle of the motor rotor 46 of the steering motor M1. Therefore, the second resolver 62 also functions as a motor rotation angle sensor that detects the motor rotation angle that is the rotation angle of the motor rotor 46. The motor rotation angle signal θm1 which is a signal of the detected motor rotation angle (the rotation angle of the second input shaft 22) is transmitted to the control device 70 via the second sensor harness 63. .

  FIG. 6 is a control block diagram showing the arithmetic circuit configuration of the control device 70.

  The control device 70 includes, in the microcomputer, a first pump drive state determination unit 73 that determines the drive state of the first pump P1, a steering motor control unit 74 that controls the drive of the steering motor M1, and a pump drive motor. And a pump drive motor control unit 75 for controlling the drive of M2. In addition, the microcomputer of the control device 70 includes a stroke end determination unit 76 that determines whether the steering mechanism 11 is at the stroke end, and a steering control that receives a steering torque signal Tr from the torque sensor 78. A torque signal receiving unit 77 and the like are provided.

  The first pump drive state determination unit 73 determines whether the vehicle is in the idling stop control period or not, and determines whether the operation of the accelerator pedal (not shown) of the vehicle is in the off state. , A hydraulic pressure drop determining unit 81 that determines whether the supply oil pressure (discharge pressure) of the first pump P1 is equal to or less than a predetermined value, and these determining units 79, 80, 81. And a final determination unit 82 that determines whether the first pump P1 is in a stopped state based on the determination result.

  The idling stop determining unit 79 determines whether or not the vehicle is in the idling stop control period based on the vehicle speed signal Vs or the engine speed signal Ne obtained by CAN (Controller Area Network) communication or the like.

  More specifically, when the vehicle speed signal Vs or the engine speed signal Ne is equal to or less than a predetermined value, the idling stop determination unit 79 determines whether the engine speed signal Ne is based on the engine speed Ne. When Ne is equal to or less than the predetermined rotation speed, it is determined that the engine E is in the idling stop control period. Then, the idling stop determination signal SigA is output to the final determination unit 82.

  When the accelerator opening signal AO acquired by the CAN communication or the like is 0, the accelerator off determination unit 80 determines that the accelerator pedal operation of the vehicle is in the off state, and sends the accelerator off determination signal SigB to the final determination unit 82. Output.

  When the hydraulic pressure signal OP transmitted from the pressure sensor 72 is equal to or less than a predetermined value, the hydraulic pressure decrease determining unit 81 determines that the hydraulic pressure supplied by the first pump P1 is decreasing, and The determination signal SigC is output to the final determination unit 82.

  When the idling stop determination signal SigA, the accelerator off determination signal SigB, or the hydraulic pressure decrease determination signal SigC is input from the preceding determination units 79, 80, 81, the final determination unit 82 is in the stopped state. Judge. Then, a first pump stop signal SigD indicating that the first pump P1 is stopped is output to the steering motor control unit 74 and the pump drive motor control unit 75.

  The steering motor control unit 74 calculates a steering motor torque command Tm1 * necessary for drive control of the steering motor M1, and a steering motor torque command Tm1 * based on the steering motor torque command Tm1 *. And a steering motor drive unit 84 that drives and controls M1.

  On the other hand, the pump drive motor control unit 75 includes a pump drive motor torque command calculation unit 85 that calculates a pump drive motor torque command Tm2 * necessary for drive control of the pump drive motor M2, and a steering motor torque command Tm. * 2, and a pump motor drive unit 86 that drives and controls the pump drive motor M2 based on * 2.

  Both motor torque command calculation units 83 and 85 function as a first pump signal receiving unit that receives a first pump stop signal SigD that is a signal indicating the driving state of the first pump P1. Then, the motor torque commands Tm1 * and Tm2 * are respectively determined based on the steering torque signal Tr received by the steering torque signal receiving unit 77 while considering the driving state of the first pump P1 based on the received first pump stop signal SigD. It is designed to calculate.

  That is, when the first pump P1 is driven, most of the necessary steering assist force is generated based on the oil pressure of the oil supplied by the first pump P1. Therefore, both motor torque command calculation units 83 and 85 convert the motor torque commands Tm1 * and Tm2 * that can compensate for a part of the steering assist force that cannot be covered by the hydraulic pressure supplied by the first pump P1 into the steering torque signal Tr. It will be calculated based on this. In a state where the steering assist force can be almost covered by the hydraulic pressure supplied by the first pump P1, both or one of the motor torque commands Tm1 * and Tm2 * can be set to zero.

  Hereinafter, the steering motor torque command Tm1 * and the pump driving motor torque command Tm2 * calculated while the first pump P1 is being driven are referred to as “steering motor torque command Tm1 * (A)” and “ Pump drive motor torque command Tm2 * (A) ".

  On the other hand, when the first pump P1 is stopped, that is, when the first pump stop signal SigD is input from the final determination unit 82 to the two motor torque command calculation units 83 and 85, the first pump P1 No hydraulic pressure is supplied, and a steering assist force based on this hydraulic pressure cannot be expected. Therefore, both motor torque command calculation units 83 and 85 provide motor torque commands Tm1 * and Tm2 that can cover all necessary steering assist forces by the hydraulic pressure supplied by second pump P2 and the motor torque output by steering motor M1. Is calculated based on the steering torque signal Tr.

  Hereinafter, the steering motor torque command Tm1 * and the pump drive motor torque command Tm2 * calculated in the stop state of the first pump P1 are referred to as “steering motor torque command Tm1 * (B)” and “pump drive torque” for convenience. Motor torque command Tm2 * (B) ".

  More specifically, when the first pump P1 stops, the steering motor torque command calculation unit 83 determines whether the steering motor torque has become equal to or more than the first torque T1 that is the first predetermined value. The calculation of the command Tm1 * (B) is started. Note that the steering motor torque command Tm1 * (B) calculated at this time is set so as to gradually increase as the steering torque signal Tr increases.

  Thus, when the first pump P1 is stopped, the steering assist force output by the steering motor M1 with respect to the steering torque input to the steering wheel has a relationship as shown in FIG. ing. In other words, the steering motor control unit 74 drives and controls the steering motor M1 so that the steering assist force output from the steering motor M1 increases in accordance with the increase in the steering torque.

  On the other hand, when the first pump P1 is stopped, the pump drive motor torque command calculation unit 85 determines that the value of the steering torque signal Tr is equal to or greater than the second torque T2 which is a second predetermined value larger than the first torque T1. In this case, the calculation of the pump driving motor torque command Tm2 * (B) is started. The pump drive motor torque command Tm2 * (B) calculated at this time is set so as to gradually increase as the steering torque signal Tr increases.

  Thus, when the first pump P1 is stopped, the rotational speed Nm2 of the pump driving motor M2 with respect to the steering torque input to the steering wheel has a relationship as shown in FIG. In other words, the pump drive motor control unit 75 drives and controls the pump drive motor M2 such that the rotation speed Nm2 of the pump drive motor M2 increases in accordance with the increase in the steering torque signal Tr. .

  In FIG. 8, the pump driving motor M2 rotates a fixed number of times even in a region where the value of the steering torque signal Tr is less than the second torque T2. However, this only improves the startability of the second pump P2. This is due to idling for improvement, and is not included in the driving control of the pump driving motor M2. Further, the idling function of the second pump P2 is not an essential function. Therefore, the pump driving motor M2 in a region where the value of the steering torque signal Tr is less than the second torque T2 can be completely set to zero. is there.

  When the stroke end determining unit 76 determines that the steering mechanism 11 is at the stroke end when the first pump P1 is stopped, the pump driving motor control unit 75 controls the driving of the pump driving motor M2. Not to be.

  The stroke end determining unit 76 receives a steering angle signal θs that is a signal of the steering angle detected by the first resolver 55, and, when the steering angle signal θs is equal to or greater than a predetermined steering angle close to the stroke end, the steering mechanism. 11 is determined to be at the stroke end. Then, a stroke end determination signal SigE is output to the pump drive motor control unit 75.

  Next, a drive control process of the steering motor M1 and the pump drive motor M2 by the control device 70 of the present embodiment will be specifically described based on the flowchart shown in FIG.

  In this flow, first, after the hydraulic pressure signal OP indicating the supply hydraulic pressure of the first pump P1 is fetched into the hydraulic pressure drop judging section 81 (Step S101), it is determined whether or not the fetched hydraulic pressure signal OP is equal to or higher than the predetermined pressure OPx. It is determined whether or not it is (step S102). Here, if it is determined to be Yes, it is determined that the first pump P1 has stopped or the normal oil supply by the first pump P1 has not been performed, and the process proceeds to subsequent Step S112.

  On the other hand, if No is determined in step S102, the accelerator opening signal AO is subsequently fetched into the accelerator off determination unit 80 (step S103), and then whether the fetched accelerator opening signal AO is 0 or not. Is determined (step S104). Here, when it is determined as Yes, the process proceeds to step S112 assuming that the first pump P1 is in the stop state due to the accelerator-off.

  On the other hand, if No is determined in step S104, the vehicle speed signal Vs is subsequently taken into the idling stop determination section 79 (step S105), and then whether or not the taken vehicle speed signal Vs is equal to or lower than the predetermined vehicle speed Vx. Judge. Here, if it is determined to be Yes, it is determined that the first pump P1 is in a stop state due to the idling stop of the engine E, and the process proceeds to step S112. In this flow, it is determined in step S105 whether the first pump P1 is in a stop state due to the idling stop of the engine E based on the vehicle speed signal Vs captured in step S104. The same determination can be made by replacing the engine speed with Ne. In this case, in step S105, when the taken engine speed Ne is equal to or less than the predetermined speed Nx, it is determined that the first pump P1 is in a stop state due to the idling stop of the engine E.

  On the other hand, if No is determined in step S106, it is determined that the first pump P1 is normally driven, and after the steering torque signal Tr is received from the torque sensor 78 via the steering torque signal receiving unit 77 ( In step S107), a steering motor torque command Tm * (A) and a pump driving motor torque command Tm2 * (A) are calculated based on the taken steering torque signal Tr (steps S108 and S109). Then, the drive control of the steering motor M1 and the pump drive motor M2 based on the motor torque commands Tm1 * (A) and Tm2 * (A) (steps S110 and S111) ends the program.

  When the process proceeds to step S112, it is considered that the first pump P1 is in a stopped state or is in an abnormal state in which oil cannot be normally supplied to the steering mechanism 11. Therefore, in a series of flows from step S112 to step S119, the steering motor torque command Tm1 * (B) and the pump drive motor torque command Tm2 * (B) when the first pump P1 stops are appropriately calculated. .

  That is, in this series of flows, first, after the steering torque signal Tr is captured (step S112), it is determined whether or not the value of the captured steering torque signal Tr is equal to or more than the first torque T1 (step S113). ). If the determination is No, the motor torque command for steering Tm1 * (B) and the motor torque command for pump drive Tm2 * (B) when the first pump P1 is stopped are calculated without calculating both motor torque commands. Tm1 * (B) and Tm1 * (B) are set to 0, and the process proceeds to step S110. In this case, the program ends without driving the steering motor M1 and the pump driving motor M2.

  On the other hand, if Yes is determined in step S113, the process proceeds to step S115 after calculating the steering motor torque command Tm1 * (B) when the first pump P1 is stopped in step S114.

  In step S115, it is determined whether or not the value of the steering torque signal Tr is equal to or greater than a second torque T2 that is larger than the first torque T1. If No is determined here, the pump drive motor torque command Tm2 * (B) is set to 0 without calculating the pump drive motor torque command Tm2 * (B), and the process proceeds to step S110. In this case, the driving of the steering motor M1 is controlled based on the steering motor torque command Tm1 * (B) when the first pump P1 is stopped, but the pump driving motor M2 is not driven, and this program ends. I do.

  On the other hand, if Yes is determined in step S115, a pump drive motor torque command Tm2 * when the first pump P1 is stopped is calculated (step S116), and the first resolver 55 outputs to the stroke end determination unit 76. After fetching the steering angle signal θs (step S117), the process proceeds to step S118.

  In step S118, it is determined whether the steering angle signal θs fetched in step S117 is equal to or larger than a predetermined angle θx. Here, if it is determined as Yes, it is determined that the steering mechanism 11 is at the stroke end, the pump driving motor torque command Tm2 * (B) is set to 0 (step S119), and the process proceeds to step S110. In this case, the driving of the steering motor M1 is controlled based on the steering motor torque command Tm1 * (B) when the first pump P1 is stopped, but the pump driving motor M2 is not driven, and this program ends. I do.

On the other hand, if No is determined in step S118, the process directly proceeds to step S110 without setting the pump drive motor torque command Tm2 * (B) to 0. In this case, the driving of the steering motor M1 is controlled based on the steering motor torque command Tm1 * (B) when the first pump P1 is stopped, and the pump driving motor M2 is the pump driving motor when the first pump P1 is stopped. Drive control is performed based on the torque command Tm2 * (B).
[Operation and effect of the present embodiment]
In a configuration such as a conventional power steering device in which the steering assist is continued by driving the second pump by the steering motor when the first pump driven by the engine is stopped due to a failure or the like, the sub pump The second pump is often smaller in capacity than the first pump, which is the main pump. In such a case, if the first pump stops, the hydraulic pressure output by the first pump cannot be covered by the second pump, and the steering assist force is insufficient, so that the driver's steering load is reduced. May increase.

  On the other hand, in the present embodiment, when the first pump P1 is stopped, not only the steering assist force based on the hydraulic pressure supplied from the second pump P2 to the steering mechanism 11, but also the motor torque output by the steering motor M1. The steering assist force based on the vehicle is also provided. That is, when the steering assist force is applied when the first pump P1 is stopped, the motor torque of the steering motor M1 provided from the viewpoint of automatic driving and the like is also taken into consideration.

  Therefore, according to the present embodiment, even when the first pump P1 is stopped, a sufficient steering assist force can be applied to the steering mechanism 11 by the second pump P2 and the steering motor M1, so that the steering load applied to the driver is reduced. Increase can be suppressed.

  In the present embodiment, the pump driving motor M2 and the steering motor M1 can be driven when the engine E is in the idling stop control period. This makes it possible to perform assist control for the steering operation (stationary operation) even when it is necessary to perform stationary operation during the idling stop control period.

  Further, in the present embodiment, the pump driving motor M2 and the steering motor M1 can be driven even when the accelerator pedal operation of the vehicle is not performed. Thus, the assist control can be performed even when the engine is stopped due to the accelerator off. In other words, the steering assist force can be applied to the steering mechanism 11 not only during a stop but also during coasting when traveling at a high speed or traveling downhill.

  Further, in the present embodiment, a pressure sensor 72 for detecting the oil pressure of the oil supplied from the first pump P1 is provided, and when the hydraulic pressure signal OP calculated by the pressure sensor 72 is equal to or less than a predetermined value OPx, the pump driving motor The driving of the M2 and the steering motor M1 is controlled. Thereby, not only when the first pump P1 is simply stopped, but also when the pipe through which the oil discharged from the first pump P1 flows is damaged, the normal oil supply by the first pump P1 is ensured. Even when it is not performed, the steering assist force can be applied to the steering mechanism 11.

  Further, in the present embodiment, focusing on the fact that the required steering assist force increases as the steering torque input to the steering wheel increases, the pump driving motor M2 and the steering motor M1 are respectively controlled based on the steering torque. Drive control. As a result, even when the steering torque is large and the load is high, a sufficient steering assist force can be applied to the steering mechanism 11, so that the driver's steering load can be effectively reduced. Further, when the steering torque is small and the load is low, the rotation speeds of the pump driving motor M2 and the steering motor M1 can be suppressed, so that energy can be saved.

  By the way, it is generally known that the steering assist using the motor torque and the steering assist using the hydraulic pressure tend to have a small output but good responsiveness, and the latter has a poor response but a large output.

  Therefore, in the present embodiment, the steering motor M1 is controlled to start driving when the value of the steering torque signal Tr becomes equal to or more than the first torque T1, and the steering torque signal Tr is controlled for the pump driving motor M2. Is started when the value becomes equal to or more than the second torque T2 which is larger than the first torque T1. This makes it possible to achieve both high responsiveness at a low load and application of a steering assist force with a large output at a high load.

  In the present embodiment, the steering motor control unit 74 does not drive the pump driving motor M2 when the steering mechanism 11 is at the stroke end. As a result, unnecessary steering force application at the stroke end can be prevented from being performed, so that energy can be saved and fuel efficiency can be improved. If the steering wheel is turned at the end of the stroke, the reaction force of the steered wheels is reflected on the first and second power cylinders C1 and C2, and there is a possibility that a feeling of steering discomfort may occur. Such a feeling of steering discomfort can be sufficiently reduced.

  Furthermore, in the present embodiment, of the first to fourth screws 39a to 39d that connect the steering motor M1 and the second housing 28, the first and second screws 39a and 39b that are arranged close to the switching valve 14. Are arranged on one side and the other side of the introduction oil passage 37 and the discharge oil passage 38 in the direction around the rotation axis X. Thereby, interference between the first and second screws 39a and 39b and the two oil passages 37 and 38 can be suppressed.

[Second embodiment]
The second embodiment of the present invention shown in FIG. 10 has substantially the same basic configuration as that of the first embodiment, except that the method of judging the decrease in the hydraulic pressure of the first pump P1 by the hydraulic pressure decrease judging section 81 has been changed. . In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and a specific description thereof will be omitted (the same as in each of the following embodiments).

  Assuming that the drive of the pump drive motor M2 is controlled based on the motor drive current I1, which is a constant and arbitrary motor drive current I, regardless of whether the first pump P1 is normal or when the fluid pressure is low, When the first pump P1 is normal, the steering assist is performed by the first pump P1, so that the value of the steering torque signal Tr becomes relatively small. Specifically, the first and second threshold values Tb1 and Tb2 shown in FIG. Will fit within. On the other hand, when the hydraulic pressure of the first pump P1 decreases, the steering assist by the first pump P1 is hardly performed, so that the value of the steering torque signal Tr is determined according to the magnitude of the motor drive current I1. , The second threshold Tb2, which is larger of the second thresholds Tb1 and Tb2.

  This is based on whether the value of the steering torque signal Tr when the arbitrary motor drive current I1 is output to the pump drive motor M2 exceeds the second threshold value Tb. This indicates that a decrease in the hydraulic pressure of P1 can be determined.

  The hydraulic pressure drop judging section 81 according to the present embodiment is configured in consideration of the above-described contents. As shown in FIG. 10, the hydraulic pressure drop judging section 81 takes in the motor driving current I1 from the pump motor driving section 86 and performs steering The steering torque signal Tr is taken in from the torque signal receiving section 77. When the value of the steering torque signal Tr is higher than the larger second threshold Tb2 of the first and second thresholds Tb1 and Tb2 determined according to the motor drive current Im, the hydraulic pressure is applied to the first pump P1. It is determined that a decrease has occurred, and a hydraulic pressure decrease determination signal SigC is output to the final determination unit 82.

  With the above configuration, according to the power steering device of the present embodiment, it is possible to obtain the same operation and effects as in the first embodiment without using the pressure sensor 72. This eliminates the need for the pressure sensor 72, so that the number of components can be reduced, thereby reducing the manufacturing cost.

  The other operation and effects are almost the same as those of the first embodiment.

[Third embodiment]
The third embodiment of the present invention shown in FIGS. 12 to 14 has the same basic configuration as that of the first embodiment, except that a pump driving motor torque command Tm2 * (B ) Is a modified version of the calculation processing.

  In setting the rotation speed Nm of the pump driving motor M2, a method is performed based on the correlation with the steering speed ωs as shown in FIG. 12, and the value of the steering torque signal Tr as shown in FIG. And a method based on the correlation of

  On the other hand, the pump driving motor torque command calculation unit 85 of the present embodiment determines the rotation speed Nm of the pump driving motor M2 in consideration of both the steering speed ωs and the steering torque signal Tr. .

  That is, as shown in FIG. 14, the pump driving motor torque command calculation unit 85 of the present embodiment basically determines the rotation speed Nm of the pump driving motor M2 based on the steering speed ωs. The increase correction can be appropriately performed according to the magnitude of the torque signal Tr.

  With this configuration, according to the power steering device of the present embodiment, when a large steering torque is input to the steering wheel, a large steering assist force can be immediately applied, so that a smooth steering feeling is secured. It is possible to do.

  Other functions and effects are almost the same as those of the first embodiment.

  The present invention is not limited to the configurations of the above embodiments, and the configurations can be changed without departing from the spirit of the invention.

  For example, in each of the above embodiments, the present invention is applied to an integral type power steering device. However, the present invention can be applied to a rack and pinion type or column type power steering device having a transmission mechanism including a rack bar and a tie rod. .

  Further, in the present embodiment, the steering motor control unit 74 and the pump drive motor control unit 75 are both provided in the microcomputer of the same control device 70. It may be provided in a computer.

  The control device provided with the steering motor control unit 74 and the control device provided with the pump drive motor control unit 75 do not necessarily need to be the same control device. That is, the pump drive motor control unit 75 may be provided in a microcomputer of a control device dedicated to the second pump P2, and the steering motor control unit 74 may be provided in a microcomputer of a separate control device. is there.

  As the power steering device based on each of the embodiments described above, for example, the following embodiments can be considered.

  In one aspect, a power steering device transmits an input shaft that rotates with a steering operation of a steering wheel, an output shaft connected to the input shaft via a torsion bar, and rotation of the output shaft to a steering wheel. And a power cylinder having a pair of hydraulic pressure chambers separated by a piston, for applying a steering assist force to the steering mechanism, and a hydraulic fluid driven by an engine of the vehicle. And a second pump driven by a pump driving motor, which is an electric motor, for discharging hydraulic fluid, and the first pump or the second pump according to the relative rotation of the input shaft and the output shaft. A rotary valve for selectively supplying hydraulic fluid supplied from a pump to a pair of hydraulic chambers of the power cylinder, and an electric motor for applying a steering force to the input shaft A motor, a control device equipped with a microcomputer, a first pump signal receiving unit provided in the control device for receiving a signal of a driving state of the first pump, and a pump drive provided in the control device. A pump drive motor control unit that drives and controls the motor for pump control, at least when the first pump is in a stopped state, a pump drive motor control unit that drives the pump drive motor, provided in the control device, A steering motor control unit that drives and controls the steering motor, the steering motor control unit driving the steering motor when at least the first pump is in a stopped state.

  In a preferred aspect of the power steering device, the pump drive motor control unit enables the pump drive motor to be driven during an idling stop control period in which an engine is stopped when a vehicle speed is equal to or lower than a predetermined value, and the steering motor control is performed. The unit is capable of driving the steering motor during the idling stop control period.

  In another preferred aspect, in any one of the aspects of the power steering device, the pump drive motor control section enables the pump drive motor to be driven when an accelerator pedal operation of the vehicle is not performed, The motor control unit for driving enables the steering motor to be driven when the accelerator pedal of the vehicle is not operated.

  In still another preferred aspect, in any one of the aspects of the power steering apparatus, the power steering apparatus includes a pressure sensor that detects a supply pressure of hydraulic fluid supplied from the first pump, When the supply hydraulic pressure of the first pump is equal to or less than a predetermined value, the motor control unit controls the drive of the pump drive motor, and the steering motor control unit determines that the supply hydraulic pressure of the first pump is When the value is equal to or less than a predetermined value, the driving of the steering motor is controlled.

  In still another preferred aspect, in any of the aspects of the power steering apparatus, the control device includes a steering torque signal receiving unit that receives a steering torque signal, and the pump driving motor control unit includes the steering torque signal. And controls the driving of the pump driving motor based on the steering torque, and the steering motor control unit controls the driving of the steering motor based on the steering torque signal.

  In still another preferred aspect, in any one of the aspects of the power steering device, the steering motor control unit drives and controls the steering motor when the steering torque is equal to or greater than a first predetermined value, and controls the driving of the pump. The motor control section controls the drive of the pump driving motor when the steering torque is equal to or greater than a second predetermined value that is larger than the first predetermined value.

  In still another preferred aspect, in any of the aspects of the power steering device, the control device includes a steering speed signal receiving unit that receives a steering speed signal, and the pump driving motor control unit includes a steering torque control unit that controls the steering torque. The driving of the pump driving motor is controlled such that the rotation speed of the pump driving motor increases in accordance with the increase or the increase in the steering speed.

  In still another preferred aspect, in any of the aspects of the power steering apparatus, the pump drive motor control unit does not drive the pump drive motor when the steering mechanism is at a stroke end.

  In still another preferred aspect, in any one of the aspects of the power steering apparatus, the power steering apparatus includes: a switching valve configured to switch between supply and cutoff of the hydraulic fluid supplied from the first pump to the rotary valve; A pair of oil passages connecting the valve and the rotary valve, wherein the switching valve is radially outside the rotary valve in a radial direction with respect to a rotation axis of the rotary valve, and is in a rotation axis direction of the rotary valve; , The steering motor is a hollow motor provided so as to surround the input shaft, and is connected to the housing by a first screw and a second screw. , The first screw rotates the rotary valve. In the direction about the axis, wherein arranged in a pair on one side of the oil passage, the second screw is located on the other side of the oil passage of said pair in a direction about the rotation axis of the rotary valve.

DESCRIPTION OF SYMBOLS 11 ... Steering mechanism, 13 ... Rotary valve, 17 ... Transmission mechanism, 18 ... Input shaft, 19 ... Output shaft, 20 ... 1st torsion bar (torsion bar), 29 ... Piston, 60 ... Control device, 74 ... Steering motor Control unit, 75: pump drive motor control unit, 83: steering motor torque command calculation unit (first pump signal reception unit), 85: pump drive motor torque command calculation unit (first pump signal reception unit), C1 ... First power cylinder (power cylinder), X1, X2 ... First and second hydraulic chambers (a pair of hydraulic chambers), E ... Engine, P1 ... First pump, P2 ... Second pump, M1 ... Steering motor , M2 ... Pump drive motor

Claims (7)

A steering mechanism having an input shaft that rotates with the steering operation of the steering wheel, an output shaft connected to the input shaft via a torsion bar, and a transmission mechanism that transmits rotation of the output shaft to the steered wheels;
A power cylinder having a pair of hydraulic chambers separated by a piston, and applying a steering assist force to the steering mechanism;
A first pump driven by an engine of the vehicle and discharging hydraulic fluid;
A second pump that is driven by a pump driving motor that is an electric motor and discharges a hydraulic fluid,
A rotary valve for selectively supplying hydraulic fluid supplied from the first pump or the second pump to a pair of hydraulic chambers of the power cylinder in accordance with the relative rotation of the input shaft and the output shaft;
A steering motor that is an electric motor that applies a steering force to the input shaft;
A control device equipped with a microcomputer;
A first pump signal receiving unit that is provided in the control device and receives a signal indicating a driving state of the first pump;
A pump drive motor control unit that is provided in the control device and that drives the pump drive motor at least when the first pump is in a stopped state;
A steering motor control unit that is provided in the control device and that drives the steering motor when at least the first pump is in a stopped state;
Have a,
The control device includes a steering torque signal receiving unit that receives a steering torque signal,
The steering motor control unit, when the steering torque is equal to or more than a first predetermined value, controls the drive of the steering motor,
The power steering device, wherein the pump drive motor control unit controls the drive of the pump drive motor when the steering torque is equal to or greater than a second predetermined value larger than the first predetermined value . The power steering device according to claim 1,
The pump drive motor control unit, during an idling stop control period for stopping the engine when the vehicle speed is equal to or less than a predetermined value, the pump drive motor can be driven,
The power steering apparatus according to claim 1, wherein the steering motor control unit is capable of driving the steering motor during the idling stop control period. The power steering device according to claim 1,
The pump drive motor control unit, when the accelerator pedal operation of the vehicle is not performed, to be able to drive the pump drive motor,
The power steering device according to claim 1, wherein the steering motor control unit is capable of driving the steering motor when an accelerator pedal operation of the vehicle is not performed. The power steering device according to claim 1,
A pressure sensor for detecting a supply fluid pressure of the working fluid supplied from the first pump,
The pump drive motor control unit, when the supply hydraulic pressure of the first pump is equal to or less than a predetermined value, controls the drive of the pump drive motor,
The power steering apparatus, wherein the steering motor control unit controls the driving of the steering motor when the supply hydraulic pressure of the first pump is equal to or less than the predetermined value. The power steering device according to claim 1 ,
The control device includes a steering speed signal receiving unit that receives a steering speed signal,
The pump drive motor control unit controls the drive of the pump drive motor such that the rotation speed of the pump drive motor increases in accordance with an increase in the steering torque or an increase in the steering speed. Power steering device. The power steering device according to claim 1,
The power steering apparatus according to claim 1, wherein the pump driving motor control unit does not drive the pump driving motor when a steering mechanism is at a stroke end. The power steering device according to claim 1,
A switching valve for switching between supply and cutoff of the hydraulic fluid supplied from the first pump to the rotary valve, and a pair of oil passages connecting the switching valve and the rotary valve;
The switching valve is disposed radially outside the rotary valve in a radial direction with respect to the rotation axis of the rotary valve, and is arranged to overlap with the rotary valve in the rotation axis direction of the rotary valve.
The steering motor is a hollow motor provided so as to surround the input shaft, and is connected to the housing by a first screw and a second screw,
The first screw is disposed on one side of the pair of oil passages in a direction around a rotation axis of the rotary valve,
The power steering device, wherein the second screw is disposed on the other side of the pair of oil passages in a direction around a rotation axis of the rotary valve.

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