JP2015098210A - Control apparatus for hydraulic power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus for a hydraulic power steering device which is equipped with plural motor pumps, and in which even if drive of one or more motor pumps is stopped, decrease of an assist force can be prevented and steering feeling can be maintained.SOLUTION: A control apparatus for a hydraulic power steering device is configured to control the rotational frequency of a first motor pump at twice the amount in the case that the first motor pump is in a normal state among state quantities of the first motor pump and a second motor pump transmitted by communication means, a current value of the first motor pump is smaller than a predetermined current value and the second motor pump is in a stopped state, or in the case that the first motor pump is in a normal state among state quantities of the first and second motor pumps transmitted by the communication means and the current value of the first motor pump is equal to or more than the predetermined current value.

Description

  The present invention relates to a control device for a hydraulic power steering device.

  2. Description of the Related Art Conventionally, a hydraulic power steering device that applies an assist force to a steering system using a hydraulic actuator such as a hydraulic cylinder is widely known. For example, Patent Document 1 discloses a hydraulic power steering apparatus that uses an electric pump that generates hydraulic pressure by driving a motor as a hydraulic pressure source of a hydraulic actuator.

JP 09-095251 A

On the other hand, in recent years, it has been proposed to provide a plurality of electric pumps in a hydraulic power steering apparatus for the purpose of further improving the assist force. But in this case,
Since the assist force at the time of high load is generated by the driving of a plurality of electric pumps, when the driving of one or more electric pumps is stopped, the assist force is insufficient and the steering feeling is deteriorated. was there.

  The present invention has been made to solve the above-described problems, and its object is to provide a plurality of electric pumps and reduce assist force even when driving of one or more electric pumps is stopped. An object of the present invention is to provide a control device for a hydraulic power steering device that can prevent and maintain a steering feeling.

  A control device for a hydraulic power steering apparatus that solves the above-described problems is provided with a first and a second for supplying hydraulic oil to a hydraulic actuator that generates an assist force for assisting a steering operation in a steering system using an electric motor as a drive source. In the control device of the hydraulic power steering apparatus provided with two electric pumps, communication means for communicating the state quantities of the first and second electric pumps to each other, and the first and second electric pumps. First and second current detecting means for detecting the first and second current values flowing, and the state quantity are normal and abnormal states of the first and second electric pumps, and the first and second electric motors. Including the first and second current values flowing through the first and second electric pumps detected by the first and second current detecting means during rotation of the pump and in a stopped state; Control means for controlling the operation of the hydraulic actuator through supply of driving power to the control means, wherein the control means includes, among the state quantities transmitted and received by the communication means, to the first and second electric pumps. When the first electric pump is in a normal state and the current value of the first electric pump is smaller than a predetermined current value, and the second electric pump is in a stopped state, or the communication means Thus, among the state quantities transmitted to and received from the first and second electric pumps, the first electric pump is in a normal state and the current value of the first electric pump is greater than or equal to a predetermined current value The control unit controls the number of rotations of the first electric pump by a factor of two, while the control unit includes a second electric motor among the state quantities transmitted and received by the communication unit to the first and second electric pumps. pump In a normal state and when the magnitude of the current value of the second electric pump is smaller than the predetermined current value and the first electric pump is in a stopped state, the rotational speed of the second electric pump is set to The gist is to control at twice.

  According to the above configuration, among the state quantities transmitted and received by the first and second electric pumps by the communication means, the first electric pump is in a normal state and the current value of the first electric pump is large. When the second electric pump is in a stopped state or when the second electric pump is in a stopped state, or out of the state quantities transmitted and received by the communication means to the first and second electric pumps, the first electric pump is In the normal state and when the current value of the first electric pump is greater than or equal to a predetermined current value, the rotation speed of the first electric pump is controlled by a factor of 2, so the flow rate of the first electric pump is also 2 It becomes possible to operate the hydraulic actuator that can prevent the assist force from decreasing and maintain the steering feeling.

  On the other hand, among the state quantities transmitted and received by the communication means to the first and second electric pumps, the second electric pump is in a normal state and the current value of the second electric pump is predetermined. If the current is smaller than the current value and the first electric pump is in a stopped state, the rotation speed of the second electric pump is controlled twice, so that the flow rate of the second electric pump is also doubled. It is possible to operate the hydraulic actuator that can prevent the assist force from decreasing and maintain the steering feeling.

  According to the present invention, there is provided a control device for a hydraulic power steering device that includes a plurality of electric pumps and that can prevent a reduction in assist force and maintain steering feeling even when driving of one or more electric pumps is stopped. Can be provided.

1 is a schematic configuration diagram of a hydraulic power steering apparatus in the present embodiment. 1 is a block diagram of a hydraulic power steering apparatus in the present embodiment. The flowchart which shows the control procedure of the 1st electric pump by the 1st microcomputer in this embodiment. The flowchart which shows the control procedure of the 2nd electric pump by the 2nd microcomputer in this embodiment.

Hereinafter, embodiments of a hydraulic power steering apparatus will be described with reference to the drawings.
A hydraulic power steering apparatus 1 shown in FIG. 1 is mounted on a vehicle having an idle stop function for automatically stopping an engine at a temporary stop. As shown in the figure, a hydraulic power steering apparatus 1 includes a steering shaft 3 to which a steering wheel 2 is fixed, a rack shaft 5 that reciprocates in the axial direction according to the rotation of the steering shaft 3, and a rack shaft 5 And a substantially cylindrical rack housing 6 which is inserted so as to be reciprocally movable. The steering shaft 3 is configured by connecting a column shaft 7, an intermediate shaft 8, and a pinion shaft 9 in this order from the steering wheel 2 side.

The rack shaft 5 and the pinion shaft 9 are arranged in the rack housing 6 with a predetermined crossing angle, and the rack teeth 5a formed on the rack shaft 5 and the pinion teeth 9a formed on the pinion shaft 9 are meshed with each other. Thus, the rack and pinion mechanism 11 is configured.
Further, tie rods 12 are connected to both ends of the rack shaft 5, and the tip of the tie rod 12 is connected to a knuckle (not shown) to which the steered wheels 13 are assembled. Therefore, in the hydraulic power steering apparatus 1, the rotation of the steering shaft 3 accompanying the steering operation is converted into the axial movement of the rack shaft 5 by the rack and pinion mechanism 11, and this axial movement is transmitted to the knuckle through the tie rod 12. Thus, the turning angle of the steered wheels 13, that is, the traveling direction of the vehicle is changed.

  The hydraulic power steering apparatus 1 also includes a hydraulic cylinder 21 as a hydraulic actuator that generates an assist force that assists the steering operation, and first and second electric pumps 22 and 23 that supply hydraulic oil to the hydraulic cylinder 21. ing. In addition, the hydraulic power steering device 1 stores hydraulic oil supplied to and discharged from the hydraulic cylinder 21 by the switching valve 24 that controls supply and discharge of hydraulic oil to the hydraulic cylinder 21 and the first and second electric pumps 22 and 23. The storage tank 25 is provided.

  The hydraulic cylinder 21 includes a cylindrical cylinder tube 31 constituted by a part of the rack housing 6. That is, the rack shaft 5 is inserted into the cylinder tube 31 so as to be able to reciprocate. The hydraulic cylinder 21 includes a piston 34 that divides the cylinder tube 31 into a first hydraulic chamber 32 and a second hydraulic chamber 33, and the piston 34 is fixed to the rack shaft 5 so as to be movable in the axial direction. Has been.

  As shown in FIG. 2, the first electric pump 22 includes a first motor 41 as a driving source, a first pump 42 that generates hydraulic pressure by being driven by the first motor 41, and an operation of the first motor 41. And a first ECU 43 for controlling the control. The second electric pump 23 includes a second motor 44 serving as a drive source, a second pump 45 that generates hydraulic pressure when driven by the second motor 44, and a second ECU 46 that controls the operation of the second motor 44. And. That is, in the present embodiment, the first and second ECUs 43 and 46 constitute a control device. As shown in FIG. 1, each suction port (not shown) of the first and second electric pumps 22 and 23 is connected to the storage tank 25 via a suction oil passage 47.

  The switching valve 24 is configured as a known rotary valve that controls supply and discharge of hydraulic oil to and from the first and second hydraulic chambers 32 and 33 of the hydraulic cylinder 21 in conjunction with the steering operation. Specifically, the switching valve 24 is provided with a supply port 51, a discharge port 52, and first and second supply / discharge ports 53 and 54. The supply port 51 is connected to the discharge ports (not shown) of the first and second electric pumps 22 and 23 via a supply oil passage 55 that branches into two branches on one end side. The discharge port 52 is connected to the storage tank 25 through a discharge oil passage 56. The first supply / discharge port 53 is connected to the first hydraulic chamber 32 via the first supply / discharge oil passage 57, and the second supply / discharge port 54 is connected to the first oil supply / discharge passage 58 via the second supply / discharge oil passage 58. 2 It is connected to the hydraulic chamber 33.

  In the hydraulic power steering apparatus 1 configured as described above, the hydraulic oil sucked up from the storage tank 25 by the first and second electric pumps 22 and 23 is supplied to the switching valve 24 via the supply oil passage 55. . Then, the hydraulic oil supplied to the switching valve 24 passes through one of the first and second oil supply / discharge passages 57 and 58 according to the driver's steering operation, and the first and second hydraulic chambers 32. , 33 is supplied. At this time, the hydraulic oil is discharged from the other one of the first and second hydraulic chambers 32 and 33, and this hydraulic oil is the other of the first and second supply / discharge oil passages 57 and 58, the switching valve 24 and the discharge oil passage. It is discharged to the storage tank 25 through 56. As a result, a hydraulic pressure difference is generated between the first hydraulic chamber 32 and the second hydraulic chamber 33, and the steering operation is assisted by the rack shaft 5 moving in the axial direction together with the piston 34 based on this hydraulic pressure difference. The

Next, the electrical configuration of the hydraulic power steering apparatus 1 will be described.
As shown in FIGS. 1 and 2, the first and second electric pumps 22 and 23 are connected to each other via a CAN (in-vehicle network) 61 (communication means). A steering sensor 62 and a vehicle speed sensor 63 are connected to the CAN 61, respectively, and a steering angle θs and a vehicle speed SPD of the steering wheel 2 are transmitted. Further, the first and second ECUs 43 and 46 cooperate with each other based on the respective state quantities obtained via the CAN 61, and the first and second electric pumps 22 and 23 (first and second motors 41 and 44). It is comprised so that operation can be controlled. In the present embodiment, the first electric pump 22 is a master and the second electric pump 23 is a slave. And the master is comprised so that rotation speed control may be continued with respect to a slave as much as possible.

  Specifically, as shown in FIG. 2, the first ECU 43 includes a first microcomputer 71 (control means) that outputs a motor control signal, and a first power that supplies driving power to the first motor 41 based on the motor control signal. And a drive circuit 72. The second ECU 46 includes a second microcomputer 73 (control means) that outputs a motor control signal, and a second drive circuit 74 that supplies drive power to the second motor 44 based on the motor control signal. The first and second drive circuits 72 and 74 are connected to the same on-vehicle power source (battery) 75 mounted on the vehicle, respectively.

  The first and second drive circuits 72 and 74 include a known PWM inverter in which a pair of switching elements (for example, FETs) connected in series is a basic unit (switching arm) and these are connected in parallel. The motor control signal is used to define the on / off state (on-duty ratio) of each switching element. Then, the first and second drive circuits 72 and 74 supply drive power based on the on-duty ratio and the voltage of the in-vehicle power supply 75 indicated by the input motor control signal to the first and second motors 41 and 44, respectively. .

  The first microcomputer 71 includes a first current sensor 76 (first current detection means) for detecting a first current value Im1 indicating a current value flowing through the first motor 41 (first electric pump 22: master), and a first A first rotation angle sensor 77 that detects a first rotation angle θm1 indicating the rotation angle of the motor 41 is connected. On the other hand, the second microcomputer 73 includes a second current sensor 78 (second current detection means) that detects a second current value Im2 indicating a current value flowing through the second motor 44 (second electric pump 23: slave), and A second rotation angle sensor 79 that detects a second rotation angle θm2 indicating the rotation angle of the second motor 44 is connected.

The first and second microcomputers 71 and 73 detect each state quantity from each sensor at a predetermined sampling period, and receive each state quantity from the CAN 61. That is,
As each state quantity, the first microcomputer 71 transmits a first current value Im1, a first electric pump normal signal P1NL, and a first electric pump rotating signal P1RV to the second microcomputer 73. On the other hand, the second microcomputer 73 transmits the second current value Im2, the second electric pump normal signal P2NL, and the second electric pump rotating signal P2RV to the first microcomputer 71. Then, the first and second microcomputers 71 and 73 control the operation of the first and second motors 41 and 44 through the supply of driving power by outputting a motor control signal based on the acquired state quantities. To do.

Next, a control procedure of the first electric pump 22 by the first microcomputer 71 in the present embodiment will be described.
As shown in FIG. 3, the first microcomputer 71 receives the steering angle θs from the CAN 61 (step S101). Next, the first microcomputer 71 receives the vehicle speed SPD from the CAN 61 (step S102). Then, the first microcomputer 71 reads the first current value Im1 of the first ECU 43 from the first current sensor 76 (step S103).

  Subsequently, the first microcomputer 71 calculates the first ECU target speed command value ω1 * based on the steering angular speed ωs obtained by differentiating the steering angle θs received from the CAN 61 and the vehicle speed SPD received from the CAN 61. (Step S104).

  Next, the first microcomputer 71 transmits the state quantities of the first ECU 43 (the first current value Im1, the first electric pump normal signal P1NL, and the first electric pump rotating signal P1RV) to the second ECU 46 by CAN61 communication. (Step S105).

  On the other hand, the first microcomputer 71 receives state quantities (second current value Im2, second electric pump normal signal P2NL, and second electric pump rotating signal P2RV) of the second ECU 46 by the first ECU 43 through CAN61 communication. (Step S106).

  Next, the first microcomputer 71 determines whether or not the first electric pump 22 is normal based on the first electric pump normal signal P1NL (step S107). Then, when the first electric pump 22 is normal (step S107: YES), the first microcomputer 71 then determines that the first current value Im1 of the first ECU 43 is smaller than the predetermined current value Io. It is determined whether or not (step S108).

  Then, when the first current value Im1 of the first ECU 43 is smaller than the predetermined current value Io (step S108: YES), the first microcomputer 71 is next in the state where the second electric pump 23 is rotating. Is determined by the second electric pump rotating signal P2RV (step S109).

  Then, when the second electric pump 23 is rotating (step S109: YES), the first microcomputer 71 executes normal rotation speed control (step S110), and the process proceeds to step S101. Transition. Here, the normal rotation speed control is to perform control with the rotation speed of the first ECU target speed command value ω1 * described in step S104.

  On the other hand, when the second electric pump 23 is stopped (step S109: NO) or when the first current value Im1 of the first ECU 43 is equal to or greater than the predetermined current value Io (step S108: NO). The first electric pump 22 executes the rotation speed double control (step S111), and proceeds to step S101. Here, the rotation speed double control means that the rotation speed is controlled at twice the first ECU target speed command value ω1 * described in step S104.

  Further, when the first electric pump 22 is not normal (step S107: NO), the first microcomputer 71 stops the rotation of the first electric pump first motor 41 (step S112), and proceeds to step S101. .

Next, a control procedure of the second electric pump 23 by the second microcomputer 73 in the present embodiment will be described.
As shown in FIG. 4, the second microcomputer 73 receives the steering angle θs from the CAN 61 (step S201). Next, the second microcomputer 73 receives the vehicle speed SPD from the CAN 61 (step S202). Then, the second microcomputer 73 reads the second current value Im2 of the second ECU 46 from the second current sensor 78 (step S203).

  Subsequently, the second microcomputer 73 calculates the second ECU target speed command value ω2 * based on the steering angular speed ωs obtained by differentiating the steering angle θs received from the CAN 61 and the vehicle speed SPD received from the CAN 61. (Step S204).

  Next, the second microcomputer 73 receives the state quantities (the first current value Im1, the first electric pump normal signal P1NL, and the first electric pump rotating signal P1RV) of the first ECU 43 through the CAN 61 communication. (Step S205).

  On the other hand, the second microcomputer 73 transmits the state quantity (second current value Im2, second electric pump normal signal P2NL, and second electric pump rotating signal P2RV) of the second ECU 46 to the first ECU 43 through CAN61 communication. (Step S206).

  Next, the second microcomputer 73 determines whether or not the second electric pump 23 is normal based on the second electric pump normal signal P2NL (step S207). Then, when the second electric pump 23 is normal (step S207: YES), the second microcomputer 73 next determines that the second microcomputer 73 has the second current value Im2 of the second ECU 46 smaller than the predetermined current value Io. It is determined whether or not (step S208).

  Then, when the second current value Im2 of the second ECU 46 is smaller than the predetermined current value Io (step S208: YES), the second microcomputer 73 next determines that the second electric motor pump 22 is rotating. Is determined by the first electric pump rotating signal P1RV (step S209).

  Then, when the first electric pump 22 is rotating (step S209: YES), the second microcomputer 73 executes normal rotation speed control (step S210), and the process proceeds to step S201. Transition. Here, the normal rotation speed control is to perform control with the rotation speed of the second ECU target speed command value ω2 * described in step S204.

  On the other hand, when the first electric pump 22 is stopped (step S209: NO), the second microcomputer 73 executes the rotation speed double control (step S211), and the process proceeds to step S201. Transition. Here, the rotation speed double control means that the rotation speed is controlled at twice the second ECU target speed command value ω2 * described in step S204.

  Furthermore, the second microcomputer 73 determines that the second current value Im2 of the second ECU 46 is equal to or greater than the predetermined current value Io (step S208: NO) or the second electric pump 23 is not normal (step S207: NO). Then, the rotation of the second motor 44 for the second electric pump is stopped (step S212), and the process proceeds to step S201.

Next, the operation and effect of the control device for the hydraulic power steering apparatus of the present embodiment configured as described above will be described.
Of the state quantities transmitted and received by the CAN 61 (communication means) to the first and second electric pumps, the first electric pump is in a normal state, and the current value of the first electric pump is a predetermined current value. If the second electric pump is in a stopped state, or out of the state quantities transmitted and received by the CAN 61 (communication means) to the first and second electric pumps, the first electric pump is In the normal state and when the magnitude of the current value of the first electric pump is equal to or greater than a predetermined current value, the number of rotations of the first electric pump is controlled by twice, while the CAN 61 (communication means) Of the state quantities transmitted to and received from the first and second electric pumps, the second electric pump is in a normal state, and the current value of the second electric pump is smaller than a predetermined current value, and The first electric pump is stopped If the state was configured to control the rotational speed of the second electric pump twice.

  According to the above configuration, among the state quantities transmitted and received by the CAN 61 (communication means) to the first and second electric pumps, the first electric pump is in a normal state and the current value of the first electric pump is When the magnitude is smaller than the predetermined current value and the second electric pump is in a stopped state, or out of the state quantities transmitted and received by the CAN 61 (communication means) to the first and second electric pumps When the first electric pump is in a normal state and the current value of the first electric pump is greater than or equal to a predetermined current value, the rotation speed of the first electric pump is controlled by a factor of two. The flow rate of the electric pump is also doubled, and it is possible to operate the hydraulic actuator that can prevent the assist force from decreasing and maintain the steering feeling.

  On the other hand, out of the state quantities transmitted and received by the CAN 61 (communication means) to the first and second electric pumps, the second electric pump is in a normal state and the current value of the second electric pump is large. Is smaller than the predetermined current value, and when the first electric pump is in a stopped state, the rotation speed of the second electric pump is controlled by a factor of 2, so that the flow rate of the second electric pump is also doubled. Thus, it is possible to operate the hydraulic actuator that can prevent the assist force from decreasing and maintain the steering feeling.

In addition, the said embodiment can also be implemented in the following aspects which changed this suitably.
In the present embodiment, the first and second electric pumps 22 and 23 are provided as the hydraulic pressure source of the hydraulic cylinder 21, but three or more electric pumps may be provided.

  In the present embodiment, the first and second electric pumps 22, 23 have the first and second ECUs 43, 46, respectively. However, the present invention is not limited to this, and the first and second motors 41, The operation of 44 may be controlled.

1: Hydraulic power steering device, 2: Steering wheel,
3: Steering shaft, 5: Rack shaft, 5a: Rack teeth,
6: rack housing, 7: column shaft, 8: intermediate shaft, 9: pinion shaft,
9a: Pinion teeth, 11: Rack and pinion mechanism, 12: Tie rod,
13: steered wheel, 21: hydraulic cylinder,
22: 1st electric pump (master), 23: 2nd electric pump (slave),
24: switching valve, 25: storage tank,
31: cylinder tube, 32: first hydraulic chamber, 33: second hydraulic chamber,
34: piston, 41: first motor, 42: first pump,
43: first ECU, 44: second motor, 45: second pump,
46: second ECU, 47: intake oil passage, 51: supply port, 52: discharge port,
53: first supply / discharge port, 54: second supply / discharge port, 55: supply oil passage, 56: discharge oil passage, 57: first supply / discharge oil passage, 58: second supply / discharge oil passage,
61: CAN (communication means), 62: steering sensor,
63: vehicle speed sensor, 71: first microcomputer (control means), 72: first drive circuit,
73: 2nd microcomputer (control means), 74: 2nd drive circuit, 75: In-vehicle power supply,
76: first current sensor (first current detection means), 77: first rotation angle sensor,
78: second current sensor (second current detection means), 79: second rotation angle sensor,
θs: steering angle, SPD: vehicle speed, ωs: steering angular velocity,
ω1 *: first ECU target speed command value,
Im1: first current value, Im2: second current value, Io: predetermined current value,
θm1: first rotation angle, θm2: second rotation angle,
ω2 *: second ECU target speed command value,
P1NL: first electric pump normal signal, P2NL: second electric pump normal signal,
P1RV: first electric pump rotating signal, P2RV: second electric pump rotating signal

Claims (1)

In a control device for a hydraulic power steering apparatus including first and second electric pumps for supplying hydraulic oil to a hydraulic actuator that generates an assist force for assisting a steering operation in a steering system using an electric motor as a drive source ,
Communication means for communicating the state quantities of the first and second electric pumps to each other;
First and second current detection means for detecting first and second current values flowing through the first and second electric pumps;
The state quantity is detected from the normal and abnormal states of the first and second electric pumps, the rotating and stopping states of the first and second electric pumps, and the first and second current detecting means. Including first and second current values flowing through the first and second electric pumps;
Control means for controlling the operation of the hydraulic actuator through supply of drive power to the electric motor,
The control means includes the state quantity transmitted to and received from the first and second electric pumps by the communication means, wherein the first electric pump is in a normal state and the current value of the first electric pump is large. Is less than a predetermined current value and the second electric pump is in a stopped state, or among the state quantities transmitted and received by the communication means to the first and second electric pumps, When the first electric pump is in a normal state and the magnitude of the current value of the first electric pump is equal to or greater than a predetermined current value, the number of revolutions of the first electric pump is controlled by twice,
The control means includes the state quantity transmitted to and received from the first and second electric pumps by the communication means, wherein the second electric pump is in a normal state and the current value of the second electric pump is large. Is less than a predetermined current value, and when the first electric pump is in a stopped state, the number of revolutions of the second electric pump is controlled to be doubled.
A control device for a hydraulic power steering device.

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