JP2014148286A - Hydraulic power steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide hydraulic power steering capable of detecting deterioration of a working fluid, notifying a driver of the deterioration, and giving a stable sense of steering even when the working fluid is deteriorated.SOLUTION: There is provided a hydraulic power steering system that determines a flow rate value of a pressure oil to be fed to a power cylinder, according to a vehicle driving situation, controls a flow rate control valve disposed at a pressure oil exhaust port of a hydraulic pump, on the basis of the flow rate value, thereby changing the flow rate of the pressure oil to be fed to the power cylinder from a feed path. The hydraulic power steering system includes flow rate measurement means 111 including a thin pipe that bypasses the feed path, heating means that heats the pressure oil in the middle of the thin pipe, pieces of temperature measurement means 340 and 341 that measure the temperature of the pressure oil on the upstream and downstream respectively of the position of the heating means, and flow rate calculation means 110 that calculates the flow rate of the pressure oil on the basis of the results of measurements by the pieces of temperature measurement means 340 and 341. The hydraulic power steering system further includes deterioration detection means 115 that detects deterioration of the pressure oil on the basis of the flow rate and temperature of the pressure oil measured by the flow rate measurement means 111.

Description

  The present invention relates to a hydraulic power steering apparatus.

  Conventionally, a flow cylinder provided with a power cylinder for assisting the rack shaft in accordance with the steering operation of the vehicle and a hydraulic pump for supplying pressure oil to the power cylinder, provided at the pressure oil discharge port of the hydraulic pump. 2. Description of the Related Art There is a hydraulic power steering apparatus that includes a controller that controls the flow rate of pressure oil flowing through a power cylinder by a valve. In this hydraulic power steering apparatus, in order to output an assist force according to the driving situation, the controller controls the pressure oil of different flow rates to be supplied to the power cylinder according to the driving situation. For this reason, the controller determines the flow rate value of the pressure oil flowing to the power cylinder according to the operating situation, determines the command value related to the opening of the flow rate control valve based on the flow rate value, and drives the flow rate control valve, By changing the opening degree of the flow control valve, the flow rate of the pressure oil supplied to the power cylinder is controlled.

  By the way, the hydraulic oil (pressure oil) used in this hydraulic power steering device has a higher viscosity and is less likely to flow when the temperature is lower. Conversely, when the temperature is higher, the viscosity is lower and the fluid is likely to flow. Are known. Conventional pressure oil flow control does not handle such temperature changes, and even if the flow control valve opening is the same, if the temperature is low, the flow rate of pressure oil per unit time decreases and the temperature When the pressure is high, the flow rate of the pressure oil becomes relatively large, and there is a problem that the assist force varies depending on the temperature of the pressure oil. For example, in Patent Document 1, an oil temperature sensor that detects the temperature of pressure oil is provided, and when the temperature is low, the flow rate control valve is controlled to be relatively large. When the temperature is high, the flow rate control valve is controlled. There is disclosed a hydraulic power steering apparatus including a controller that controls the opening of the engine to be relatively small.

Japanese Patent Application Laid-Open No. 2002-347643

  However, this hydraulic oil deteriorates with use, and the viscosity of the hydraulic oil changes not only with temperature but also with deterioration, and the deteriorated hydraulic oil has a lower viscosity. In some cases, the steering feeling may be deteriorated due to insufficient control. In addition, the deteriorated hydraulic oil may cause problems such as loss of circulation in the hydraulic pump and equipment, seal corrosion, and abnormal friction of the sliding portion. In this way, hydraulic oil is not only used as a power transmission medium, but also has actions such as lubrication, rust prevention, cooling, etc. In order to fully demonstrate the functions of the hydraulic power steering device, at an appropriate timing Management such as exchange is also important.

  The present invention has been made to solve the above problems, and the problem to be solved by the present invention is to detect the deterioration of the hydraulic oil and notify the driver, and the hydraulic oil has deteriorated. However, it is to provide a hydraulic power steering capable of obtaining a stable steering feeling.

  According to a first aspect of the present invention, there is provided a power cylinder that assists a rack shaft in accordance with a steering operation of a vehicle, a hydraulic pump that supplies a predetermined amount of pressure oil to the power cylinder, and a pressure oil of the hydraulic pump. A controller for controlling the flow rate of the pressure oil flowing from the pressure oil supply path to the power cylinder by a flow rate control valve provided at the discharge port, and the controller that has received information on the operating status of the vehicle, The flow rate value of the pressure oil flowing through the power cylinder is determined according to the operating status, and the flow rate control valve is driven based on the flow rate value to obtain a command value related to the opening of the flow rate control valve, and the flow rate In the hydraulic power steering apparatus that changes the flow rate of the pressure oil fed from the feed path to the power cylinder by changing the opening of the control valve A fine rod that bypasses the supply path, a heating means that heats the pressure oil in the middle of the fine line, a temperature measuring means that measures the temperature of the pressure oil upstream and downstream from the position of the heating means, A flow rate measurement means comprising a flow rate calculation means for calculating the flow rate of the pressure oil based on the measurement result of the temperature measurement means is provided, and the deterioration of the pressure oil is detected from the flow rate and temperature of the pressure oil measured by the flow rate measurement means. It is characterized in that a deterioration detecting means is provided.

  According to the invention of claim 1 configured as described above, the fine oil supply passage that bypasses the supply passage is provided in the supply passage for the pressure oil supplied to the power cylinder, and the pressure oil is supplied in the middle of the fine passage. Heating means for heating and temperature measuring means for measuring the temperature of the pressure oil upstream and downstream from the position of the heating means are provided. The pressure oil that bypasses the feed path and flows through the fine rod is heated by the heating means, and the temperature rises. In the flow rate measuring means, the amount of heat transferred per unit time of the pressurized oil, which is a fluid, is obtained by multiplying the constant pressure specific heat by the rising temperature and the flow rate. The flow rate of oil can be calculated. The deterioration detecting means can detect the deterioration of the pressure oil from the calculated flow rate of the pressure oil and the measured temperature of the pressure oil.

  The invention according to claim 2 is the hydraulic power steering apparatus according to claim 1, wherein when the deterioration detecting means detects the deterioration of the pressure oil, the notifying means for notifying the driver of the vehicle. And the controller is configured to control the flow rate of the pressure oil flowing through the power cylinder by feeding back the actual flow rate of the pressure oil measured by the flow rate measuring means.

  According to the invention of claim 2 configured as described above, the deterioration detecting means can notify the driver of the detected hydraulic oil to the vehicle driver, so that the hydraulic oil can be appropriately managed. . In addition, the flow rate of the pressure oil measured by the flow rate measuring means is fed back to the flow rate of the pressure oil to the power cylinder determined according to the operating condition, and the flow rate control valve is controlled to converge the flow rate deviation. Therefore, even if the hydraulic oil is deteriorated, a stable steering feeling can be obtained.

  According to the present invention, it is possible to provide a hydraulic power steering capable of detecting the deterioration of the hydraulic oil and notifying the driver, and obtaining a stable steering feeling even when the hydraulic oil is deteriorated. .

1 is a perspective view of a hydraulic power steering apparatus according to an embodiment of the present invention. It is sectional drawing of the flow control valve of the hydraulic power steering device which concerns on embodiment of this invention. It is a principal part expanded sectional view of the flow control valve of FIG. It is a block diagram explaining the structure of the data processing of the controller of the hydraulic type power steering device which concerns on embodiment of this invention. It is the graph which showed the relationship between the electric current sent through the electromagnetic coil for every temperature of pressure oil, and flow volume.

Hereinafter, a hydraulic power steering apparatus according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the hydraulic power steering apparatus 1 according to this embodiment includes a rack shaft (not shown) having a rack gear and a pinion shaft 4 having a pinion gear (not shown). And a steering gear box 5 containing a rack and pinion gear mechanism.

  The hydraulic power steering device 1 includes a power cylinder 2 that assists the rack shaft with an assist force according to a steering operation of the vehicle, a hydraulic pump 10 that supplies a predetermined amount of pressure oil to the power cylinder 2, and the power cylinder 2. And a steering valve 40 for switching the flow path of the pressure oil. A flow rate control valve 12 is provided at the pressure oil discharge port of the hydraulic pump 10, and the flow rate control valve 12 is provided with a feed path through which pressure oil can be fed toward the power cylinder.

  The hydraulic power steering apparatus 1 detects a speed of a vehicle, a controller 50 for controlling the flow control valve 12, a steering angle sensor 310 for detecting a steering angle of the steering wheel input to the steering handle 3. A vehicle speed sensor 510. Then, the controller 50 that has received information on the driving state of the vehicle via the in-vehicle network 500 from the steering angle sensor 310 and the vehicle speed sensor 510 determines the flow rate value of the pressure oil that flows to the power cylinder 2 according to the driving state. doing. The in-vehicle network 500 is a network that connects between in-vehicle electronic devices, and can be exemplified by a CAN (Controller Area Network).

  The controller 50 obtains a command value related to the opening degree of the flow control valve 12 based on the flow value, drives the flow control valve 12, and changes the opening degree of the flow control valve 12. As a result, the flow rate of the pressure oil supplied from the supply path to the power cylinder 2 out of the pressure oil discharged by the hydraulic pump 10 is controlled.

  As shown in FIG. 2, the flow control valve 12 shares the housing 13 with the hydraulic pump 10, and the pressure oil discharge port of the hydraulic pump 10 formed in the housing 13 communicates with each internal space of the flow control valve 12. doing. The flow control valve 12 is formed in an axial shape, and has an internal space extending in the axial direction partitioned into a plurality of rooms. Among these rooms, the room where the pressure oil discharge port is opened is the input port 15 of the flow control valve 12.

  On both sides of the input port 15 in the axial direction of the flow control valve 12, a feed port 16 and a circulation port 17 are provided. The feed port 16 has an inner nozzle 18 projecting from the input port 15 side and a movable plug 19 projecting from the opposite side of the input port 15, and the tips of the inner nozzle 18 and movable plug 19 are butted together. ing.

  A plurality of lateral holes 15A are formed at the base end portion of the inner nozzle 18, and the input port 15 communicates with the inner space of the inner nozzle 18 through the lateral holes 15A. A throttle hole 18 </ b> A is formed at the tip of the inner nozzle 18. The throttle hole 18 </ b> A has a tapered diameter from both axial directions, and opens the inner space of the inner nozzle 18 to the feeding port 16.

  The movable plug 19 is slidable in the axial direction and is biased toward the inner nozzle 18 by a coil spring 21. As a result, the cylindrical end portion 19A of the movable stopper 19 is always in contact with the outer tapered surface of the throttle hole 18A in the inner nozzle 18 to close the throttle hole 18A.

  Further, the movable plug 19 slides away from the inner nozzle 18 by exciting the electromagnetic coil 23 assembled at one end of the flow control valve 12, and the throttle hole 18A is opened according to the sliding amount. At this time, the variable orifice 20 is constituted by a gap formed between the cylindrical end portion 19A of the movable stopper 19 and the throttle hole 18A of the inner nozzle 18. Then, the opening of the variable orifice 20 is changed according to the magnitude of the current flowing through the electromagnetic coil 23.

  A communication hole 18B that is smaller than the throttle hole 18A is open to the side at the tip of the inner nozzle 18. Thereby, even if the throttle hole 18A is closed, a small amount of pressurized oil that can pass through the communication hole 18B flows from the input port 15 to the feed port 16.

  The movable plug 19 is formed with a communication passage 19B for equalizing the internal pressure in the chambers on both sides of the flow control valve 12 (the feeding port 16 and the accommodating chamber 22 of the coil spring 21) with the movable plug 19 in between. ing.

  The recirculation port 17 disposed on the opposite side of the feed port 16 with the input port 15 interposed therebetween is in a state of being disconnected from the input port 15 by the differential valve 25. Specifically, the circulation port 17 is configured by an annular groove formed in a part in the axial direction of the inner peripheral surface of the housing 13 in which the differential valve 25 is accommodated.

  On the other hand, the differential valve 25 is slidable so as to be in contact with and away from the base end surface of the inner nozzle 18 and is biased toward the input port 15 by a coil spring 28 provided on the side opposite to the input port 15 to It is abutted against the base end face of the nozzle 18. Further, the differential valve 25 includes a small diameter portion at an axial intermediate portion, and the first and second large diameter portions 26 and 27 provided before and after the small diameter portion slide on the inner peripheral surface of the housing 13. To do.

  The first large-diameter portion 26 on one end side of the differential valve 25 is positioned between the circulation port 17 and the input port 15 in a state where the differential valve 25 is abutted against the proximal end portion of the inner nozzle 18. Thus, the circulation port 17 and the input port 15 are blocked.

  Further, when the first large diameter portion 26 moves to the recirculation port 17 side by moving the differential valve 25 away from the input port 15, the recirculation port 17 and the input port 15 communicate with each other. Pressure oil flows through the reflux port 17. Further, the second large diameter portion 27 always blocks the space between the spring accommodating chamber 29 provided on the opposite side of the input port 15 and the circulating port 17 with the differential valve 25 interposed therebetween.

  The spring accommodating chamber 29 and the feeding port 16 are connected to each other by a pressure transmission path 30 extending in parallel with a space in the housing 13 in which the inner nozzle 18 and the differential valve 25 are accommodated. Thereby, the same internal pressure as that of the feed port 16 is applied to the end face of the differential valve 25 on the spring accommodating chamber 29 side. The internal pressure of the input port 15 is applied to the end face of the differential valve 25 on the input port 15 side.

  Here, since the diameters of both end faces of the differential valve 25 are equal, when the internal pressure applied to both end faces of the differential valve 25 is the same, the differential valve 25 and the input port 15 are recirculated by the elastic force of the coil spring 28. The port 17 is held in a closed position.

  On the other hand, when the internal pressure applied to the end face on the input port 15 side of the differential valve 25 is greater than the internal pressure applied to the end face on the feed port 16 side, and the difference between the internal pressures exceeds the pressing force of the coil spring 28. Then, the differential valve 25 moves in the direction in which the coil spring 28 is compressed, and the input port 15 and the circulation port 17 are connected. Then, the pressure oil having a flow rate corresponding to the movement amount of the differential valve 25 flows from the input port 15 to the circulation port 17. Therefore, the differential valve 25 plays a role of maintaining the differential pressure between the input port 15 and the feed port 16 at a constant level.

  Here, the flow rate flowing through the variable orifice 20 is determined by the differential pressure between the input port 15 and the feed port 16 and the opening of the variable orifice 20. Since a constant differential pressure is maintained between the input port 15 and the feed port 16, the flow rate of the pressure oil flowing through the variable orifice 20 is changed by changing the opening of the variable orifice 20.

  As described above, the opening of the variable orifice 20 is changed by the value of the current flowing through the electromagnetic coil 23, and the pressure oil having a flow rate corresponding to the opening of the variable orifice 20 passes from the input port 15 through the variable orifice 20 to the feed port. 16 flows. At this time, the excessive amount of pressure oil that did not flow to the feed port 16 supplied from the hydraulic pump 10 to the flow rate control valve 12 flows from the input port 15 to the circulation port 17.

  The circulation port 17 communicates with the inner space of the circulation nozzle 32, and a pipe (not shown) connected to the circulation nozzle 32 communicates with the oil tank 45 on the suction port side of the hydraulic pump 10.

  On the other hand, the feed port 16 communicates with the inner space of the feed nozzle 31, is connected to a steering valve 40 to a pipe (not shown) connected to the feed nozzle 31, and further power is connected to the output side of the steering valve 40. Connected to the cylinder 2. The inner space of the feed port 16 and the feed nozzle 31 corresponds to the feed path according to the invention.

  The power cylinder 2 has a known structure for outputting an assist force for steering operation. That is, a linear motion shaft (not shown) is inserted inside the power cylinder 2, and the interior of the power cylinder 2 is divided into two chambers in the axial direction by a piston (not shown) fixed in the middle of the linear motion shaft. It is divided. The linear motion shaft is driven by the differential pressure between the two rooms, and an assist force is applied to the link mechanism connected to the steering wheel (for example, the front wheel) of the automobile.

  Further, the two chambers of the power cylinder 2 communicate with the steering valve 40. The steering valve 40 also has a known structure, and operates in conjunction with the operation of the steering wheel so that a differential pressure is generated between the two chambers of the power cylinder 2 when the steering wheel starts to be turned. Operate. Thereby, the power cylinder 2 outputs direct power (assist force) so as to assist the steering operation.

  In the present embodiment, a narrow rod-shaped bypass pipe 34 that bypasses the pressure oil supply path that connects the flow control valve 12 to the power cylinder 2 is provided. As shown in FIG. 3, the bypass pipe 34 includes a heater 35 that is a heating means for heating the pressure oil flowing through the bypass pipe 34, and a temperature sensor that is a temperature measurement means on each of the upstream side and the downstream side of the heater 35. 340 and a temperature sensor 341 are attached. The two temperature sensors 340 and 341 constitute a part of the bridge circuit 36.

  The controller 50 also captures information on the vehicle speed, steering angle, and steering angular speed, which is information relating to the driving situation of the vehicle, and the command value I5 of the current flowing through the electromagnetic coil 23 is determined based on these information. The flow control valve 12 is driven based on the command value I5.

Next, the data processing configuration in the controller 50 will be described.
As shown in FIG. 4, the controller 50 stores a map 100 that stores a command value I1 of a current that flows through the electromagnetic coil 23 for each steering angle, and a command value of a current that flows through the electromagnetic coil 23 for each steering angular velocity. A map 101 storing I2, a map 102 storing a command value I3 of current flowing through the electromagnetic coil 23 for each vehicle speed for each steering angle, and a command value of current flowing through the electromagnetic coil 23 for each vehicle angular velocity. And a map 103 storing I4.

  The controller 50 takes these steering angle, steering angular velocity, and vehicle speed into the controller 50, and obtains command values I1 to I4 corresponding to the steering angle, steering angular velocity, and vehicle speed from the maps 100 to 103. Then, in the command value calculation block 105, command values I1 to I4 are multiplied to calculate a command value I5 (= I1 × I2 × I3 × I4) of a current flowing through the electromagnetic coil 23.

  Further, the controller 50 includes a flow rate measuring unit 111 and a flow rate calculating unit 110, and heats the pressure oil flowing through the bypass pipe 34 with the heater 35, and temperature sensors 340 attached to the upstream side and the downstream side from the position of the heater 35. , 341, the temperature of the pressure oil at each position is measured.

  The flow rate calculation means 110 transmits an electrical signal corresponding to the flow rate to the controller 50 by the temperature difference detected by the temperature sensors 340 and 341 changing the balance of the bridge circuit 36. The controller 50 receives this electrical signal and calculates the flow rate flowing through the power cylinder 2. This flow rate measurement method is based on the fact that the amount of heat transferred per unit time of pressurized oil, which is a fluid, is obtained by multiplying the constant pressure specific heat by the rising temperature and the flow rate.

  The calculated flow rate is converted into a flow rate corresponding current value I6 by the flow rate / current conversion means 112. In the flow rate / current conversion means 112, the flow rate / current stored in the flow rate corresponding current value I6 as the flow rate corresponding current value I6 corresponding to various flow rates of the pressure oil flowing in the power cylinder 2 and obtaining these flow rates. A conversion map is provided. Then, the flow rate / current conversion unit 112 obtains the flow rate corresponding current value I6 from the flow rate / current conversion map based on the actual flow rate actually measured by the flow rate measurement unit 111.

  Further, the controller 50 subtracts the flow-corresponding current value I6 from the command value I5 of the current flowing through the electromagnetic coil 23, obtains a deviation, differentiates the deviation by a constant, a value obtained by time-integrating the deviation, and the deviation The corrected current value I7 is generated by adding these values. That is, proportional control and integral control (hereinafter referred to as PID control) are performed to correct the command value I5 and generate a corrected current value I7. Then, the correction current value I7 is given to the drive circuit 114 to excite the electromagnetic coil 23. Then, the movable plug 19 of the variable orifice 20 provided in the flow rate control valve 12 is linearly moved by receiving a magnetic force, whereby the opening degree of the variable orifice 20 is determined, and the pressure oil of a predetermined flow rate is supplied from the hydraulic pump 10 to the power cylinder 2 side. Flowing into.

  In addition, the controller 50 includes a deterioration detecting unit 115 including a flow rate measuring unit 111 and a temperature sensor 340. Here, the hydraulic oil used for pressure oil has a higher viscosity when the temperature is lower and becomes difficult to flow. Conversely, when the temperature is higher, the viscosity becomes lower and the flow is easier. It is specified by a constant determined by the flow path.

  On the other hand, the viscosity of the hydraulic oil changes not only due to temperature change but also due to deterioration, and the deteriorated hydraulic oil has a low viscosity. The deterioration detecting means 115 corresponds to various flow rates of the pressure oil for each temperature of the non-deteriorated hydraulic oil, and stores a map 104 that stores command values of currents that flow through the electromagnetic coil 23 in order to obtain those flow rates. I have.

Next, the operation of the present embodiment configured as described above will be described.
When the ignition is turned on and the engine of the vehicle rotates, pressure oil is supplied from the hydraulic pump 10 to the flow control valve 12. Then, the controller 50 determines a command value I5 related to the opening degree of the flow control valve 12 (that is, the opening degree of the variable orifice 20) according to the driving conditions of the steering angle, the steering angular speed, and the vehicle speed. Thereby, the flow volume of the pressure oil fed from the hydraulic pump 10 to the power cylinder 2 side is determined.

  FIG. 5 is a graph showing the relationship between the temperature of the pressure oil, the value of the current flowing through the electromagnetic coil 23, and the flow rate fed from the feed port 16 of the hydraulic pump 10 to the power cylinder 2 side. The temperature of the pressure oil shown in this graph is t1 <t2 <t3, and even if the current value flowing through the electromagnetic coil 23 is the same, the viscosity decreases and the flow easily occurs when the temperature of the pressure oil increases. This increases the flow rate. Here, since the viscosity of the hydraulic oil used for the pressure oil decreases when it deteriorates, even when the temperature of the pressure oil is low or high, even if the current value flowing through the electromagnetic coil 23 is the same, the flow rate is low. Becomes larger.

  The deterioration detecting means 115 is a flow rate corresponding to the current command value and the pressure oil actually measured by the flow rate measuring means 111 from the temperature actually measured by the temperature sensor 340 in the map 104 for each temperature of the undegraded hydraulic oil. When the difference exceeds a predetermined range, it is detected as deterioration of the hydraulic oil. When the deterioration detecting means 115 detects the deterioration of the hydraulic oil, the controller 50 sends a signal to the console panel 600 of the driver's seat and operates the driver by lighting a warning lamp provided in the console panel 600. Notify oil deterioration.

  Further, the controller 50 causes the PID to converge the deviation between the current command value I5 for exciting the electromagnetic coil 23 and the flow rate corresponding current value I6 obtained from the flow rate of the pressure oil actually measured by the flow rate measuring means 111. Take control. As a result, the flow rate of the pressure oil is controlled so that the command value I5 and the flow-corresponding current value I6 coincide with each other, and finally the pressure oil having the flow rate determined by the controller 50 is supplied from the hydraulic pump 10. The

  As described above, according to the hydraulic power steering apparatus 1 of the present embodiment, the deterioration of the hydraulic oil is detected and notified to the driver, and even if the hydraulic oil is deteriorated, the current command to be passed through the electromagnetic coil 23 is commanded. A predetermined flow rate of pressure oil can be supplied to the value I5, and a stable steering feeling can be obtained.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims. For example, in the above-described embodiment, the current command value related to the opening degree of the flow control valve 12 is feedback-controlled, but the feedback control may be performed using the flow rate of the supplied pressure oil as the command value.

1: Hydraulic power steering device, 2: Power cylinder, 3: Steering handle, 4: Pinion shaft, 5: Steering gear box, 10: Hydraulic pump, 12: Flow control valve, 13: Housing, 15: Input port, 16: Feeding port, 17: Circulation port, 18: Inner nozzle, 18A: Restriction hole, 18B: Communication hole, 19: Movable stopper, 19A: Cylindrical tip, 20: Variable orifice, 21: Coil spring, 22: Storage chamber 23: Electromagnetic coil, 25: Differential part, 26: Large diameter part, 27: Large diameter part, 28: Coil spring, 29: Spring accommodating chamber, 30: Pressure transmission path, 31: Feed nozzle, 32: Circulation nozzle 34: Bypass pipe, 35: Heater (heating means), 36: Bridge circuit, 40: Steering valve, 45: Oil tank, 50: Control Roller, 100 to 104: Map, 105: Command value calculation block, 110: Flow rate calculation means, 111: Flow rate measurement means, 112: Flow rate / current conversion means, 113: PID control block,
114: drive circuit, 115: deterioration detection means, 310: steering angle sensor, 320: steering angular velocity sensor, 330: vehicle speed sensor, 340: temperature sensor (upstream side), 341: temperature sensor (downstream side), 500: in the vehicle Network 600: Console panel

Claims (2)

A power cylinder that assists the rack shaft in accordance with the steering operation of the vehicle, a hydraulic pump that supplies a predetermined amount of pressure oil to the power cylinder, and a flow rate control provided at the pressure oil discharge port of the hydraulic pump A controller for controlling a flow rate of the pressure oil flowing from the pressure oil supply path to the power cylinder by a valve;
The controller that has received information on the driving situation of the vehicle determines a flow value of the pressure oil that flows to the power cylinder in accordance with the driving situation, and relates to an opening of the flow control valve based on the flow value. Hydraulic power steering that changes the flow rate of the pressure oil supplied from the supply path to the power cylinder by driving the flow control valve by obtaining a command value and changing the opening of the flow control valve In the device
A fine rod that bypasses the supply path, a heating means that heats the pressure oil in the middle of the fine line, a temperature measuring means that measures the temperature of the pressure oil upstream and downstream from the position of the heating means, A flow rate measurement means comprising a flow rate calculation means for calculating the flow rate of the pressure oil based on the measurement result of the temperature measurement means is provided, and the deterioration of the pressure oil is detected from the flow rate and temperature of the pressure oil measured by the flow rate measurement means. A hydraulic power steering apparatus characterized by comprising a deterioration detecting means. The hydraulic power steering device according to claim 1,
A notification means for notifying the driver of the vehicle when pressure oil deterioration is detected by the deterioration detection means;
The controller is configured to feed back an actual flow rate of the pressure oil measured by the flow rate measuring unit and control a flow rate of the pressure oil flowing to the power cylinder.

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