JP2015093563A - Control device of hydraulic power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a hydraulic power steering device which can suppress excessive consumption of a current while being provided with a plurality of electric pumps.SOLUTION: A control device includes: first and second current detection means which detect first and second current values flowing through first and second electric pumps; transmission means which transmits the second current value detected from the second current detection means to the first electric pump; and control means which controls actuation of a hydraulic actuator through drive power supply to an electric motor. The control means stops actuation of the second electric pump when a sum of the first current value detected from the first current detection means and the second current value detected from the second current detection means transmitted by the transmission means is larger than a 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. However, in this case, there is a problem that a very large amount of current is consumed at a high load.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a control device for a hydraulic power steering device that includes a plurality of electric pumps and can suppress an excessive current consumption. Is to provide.

  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 having two electric pumps, first and second current detecting means for detecting first and second current values flowing through the first and second electric pumps; A transmission means for transmitting the second current value detected from the two current detection means to the first electric pump; and a control means for controlling the operation of the hydraulic actuator through the supply of drive power to the electric motor, The control means detects the first current value detected from the first current detection means and the second current detection means transmitted by the transmission means. If the sum of the current value of 2 is larger than the predetermined current value, and summarized in that stops the operation of the second electric pump.

  According to the above configuration, when the sum of the first and second current values flowing through the first and second electric pumps is greater than the predetermined current value, the operation of the second electric pump is stopped. It is possible to suppress the current consumption from becoming excessive, and at the same time, it is possible to operate the hydraulic actuator up to the maximum usable current value.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the consumption of an electric current becomes excessive, providing a some electric pump.

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 FIG.1 and FIG.2, the 1st and 2nd electric pumps 22 and 23 are mutually connected via CAN (in-vehicle network) 61 (transmission 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. The first and second current values Im1 and Im2 are transmitted from the first and second microcomputers 71 and 73 to the CAN 61, respectively. 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, the control procedure of the first electric pump by the first microcomputer in this 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). Next, the first microcomputer 71 reads the first current value Im1 of the first ECU from the first current sensor 76 (step S103). Next, the first microcomputer 71 receives the second current value Im2 of the second ECU read from the second current sensor 78 from the CAN 61 (step S104).

  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. Then, speed control is executed (step S105).

  Next, the first microcomputer 71 determines whether or not the sum of the first current value Im1 of the first ECU and the second current value Im2 of the second ECU is smaller than the predetermined current value Io (step S106). When the sum of the first current value Im1 of the first ECU and the second current value Im2 of the second ECU is smaller than the predetermined current value Io (step S106: YES), the first microcomputer 71 Normal rotation speed control is executed (step S107).

  On the other hand, when the sum of the first current value Im1 of the first ECU and the second current value Im2 of the second ECU is equal to or greater than the predetermined current value Io (step S106: NO), the first microcomputer 71 stops the second electric pump. Command COMSTP2 is transmitted to the second ECU at CAN 61 (step S108), the process proceeds to step S107, and the first electric pump executes normal rotation speed control.

Next, the control procedure of the second electric pump by the second microcomputer in this 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). Next, the second microcomputer 73 reads the second current value Im2 of the second ECU from the second current sensor 78 (step S203). Next, the second microcomputer 73 transmits the second current value Im2 of the second ECU read from the second current sensor 78 to the first ECU through the CAN 61 (step S204).

Subsequently, the second microcomputer 73 calculates a 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. Then, speed control is executed (step S205).
Next, the second microcomputer 73 determines whether or not the second electric pump stop command COMSTP2 signal is transmitted from the first ECU to the second ECU via the CAN (step S206).

  Then, when the second electric pump stop command COMSTP2 signal is not transmitted from the first ECU to the second ECU via the CAN (step S206: YES), the second microcomputer 73 rotates the second electric pump at the normal rotation. Number control is executed (step S207). On the other hand, when the second electric pump stop command COMSTP2 signal is transmitted from the first ECU to the second ECU via CAN (step S206: NO), the second microcomputer 73 is the second motor for the second electric pump. The supply of drive power to 44 is stopped, and the second motor 44 is stopped (step S208).

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.
First and second current detection means for detecting the first and second current values flowing through the first and second electric pumps, and the second current value detected from the second current detection means as the first electric pump And a control means for controlling the operation of the hydraulic actuator through supply of drive power to the electric motor, the control means transmitting the first current value detected from the first current detection means, and the transmission When the sum of the second current value detected from the second current detection means transmitted by the means is larger than the predetermined current value, the operation of the second electric pump is stopped.

  According to the above configuration, when the sum of the first and second current values flowing through the first and second electric pumps becomes larger than the predetermined current value, the operation of the second electric pump can be stopped. it can. As a result, it is possible to prevent the current consumption from becoming excessive, and at the same time, it is possible to operate the hydraulic actuator up to the maximum usable current value.

In addition, the said embodiment can also be implemented in the following aspects which changed this suitably.
In the present embodiment, the first electric pump 22 is the master and the second electric pump 23 is the slave, and the sum of the first current value Im1 of the first ECU and the second current value Im2 of the second ECU is equal to or greater than the predetermined current value Io. In this case, the rotational speed control of the first electric pump is continued. However, the present invention is not limited to this method, and the second electric pump 23 may be a master and the first electric pump 22 may be a slave so that the rotational speed control of the second electric pump 23 is continued.

  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 (transmission means), 62: Steering sensor,
63: vehicle speed sensor, 71: first microcomputer (control means), 72: first drive circuit,
73: second microcomputer (control means), 74: second drive circuit, 75: on-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,
COMSTP2: Second electric pump stop command,
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

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 ,
First and second current detection means for detecting first and second current values flowing through the first and second electric pumps;
Transmitting means for transmitting the second current value detected from the second current detecting means to the first electric pump;
Control means for controlling the operation of the hydraulic actuator through supply of drive power to the electric motor,
The control means is configured such that a sum of a first current value detected from the first current detection means and a second current value detected from the second current detection means transmitted by the transmission means is greater than a predetermined current value. If larger, stopping the operation of the second electric pump;
A control device for a hydraulic power steering device.

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