JP2017035959A - Hydraulic steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic steering device which allows an operator to feel a reaction force according to a steering state from an operation member.SOLUTION: A hydraulic steering device includes: a hydraulic cylinder for oscillating a front vehicle body with respect to a rear vehicle body according to an operation amount of a steering wheel; a steering angle sensor 6 for acquiring a steering angle of a steering shaft connected to the steering wheel; and a reaction force application device for applying a reaction force with respect to the steering shaft in the opposite direction from the steering direction. The reaction force application device includes: an electric motor 31 for applying the reaction force to the steering shaft; and a target reaction force determination part 41 for determining a target current of the reaction force applied to the steering shaft, based on the steering angle acquired by the steering angle sensor 6. The electric motor 31 is controlled based on the target current.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hydraulic steering device.

  Patent Document 1 describes a hydraulic steering device applied to an articulated construction machine in which a front vehicle body and a rear vehicle body are rotatably connected via a connecting pin. In the hydraulic steering device described in Patent Document 1, the user tilts the operation lever to the left and right, switches the position of the steering valve via the pilot valve, and expands and contracts the two cylinders attached to the vehicle body. The main body is rotated left and right with respect to the rear body.

JP 2007-106308 A

  However, in the hydraulic steering device described in Patent Document 1, since the operation lever and the front vehicle body are not mechanically connected, the front vehicle body is rotated when the front vehicle body is rotated left and right with respect to the rear vehicle body. I could not feel the reaction force received by the wheel from the control lever. If the reaction force cannot be felt from the operation lever in this way, it is difficult for the operator to sensuously recognize the steering state such as the angular position of the operation lever from the operation lever.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hydraulic steering device that allows a driver to feel a reaction force according to a steering state from an operation member.

  A first aspect of the present invention is a hydraulic steering device that steers a work vehicle having a front vehicle body and a rear vehicle body that is swingably connected to the front vehicle body by a connection mechanism, and a working fluid supplied from a pump A fluid pressure actuator that is driven by and swings the front vehicle body relative to the rear vehicle body according to the operation amount of the steering member, a steering angle acquisition unit that acquires a steering angle of a steering shaft coupled to the steering member, and steering A reaction force applying device that applies a reaction force to the shaft in a direction opposite to the steering direction. The reaction force applying device is acquired by the electric motor that applies the reaction force to the steering shaft and the steering angle acquisition unit. A target reaction force determination unit that determines a target value of a reaction force to be applied to the steering shaft based on the steering angle, and the electric motor is based on the target value determined by the target reaction force determination unit It is controlled.

  In the first invention, a reaction force is applied to the steering shaft by controlling the electric motor based on the steering angle acquired by the steering angle acquisition unit.

  The second invention is characterized in that the target value of the reaction force applied to the steering shaft is determined according to the vehicle speed of the work vehicle.

  In the second aspect of the invention, since the reaction force corresponding to the vehicle speed is given to the steering shaft in addition to the steering angle of the steering member, the steering feeling is improved.

  The third invention further includes a torque sensor that detects a steering torque acting between the steering member and the reaction force applying device on the steering shaft, and the electric motor has a target value determined by the target reaction force determination unit, Control is performed based on a difference from the steering torque detected by a torque sensor.

  In the third aspect of the invention, the electric motor 31 is controlled based on the difference between the target value determined by the target reaction force determination unit and the steering torque detected by the torque sensor. The force can be applied with high accuracy.

  According to a fourth aspect of the present invention, the reaction force applying device further includes a speed calculating unit that calculates the speed of the steering member, and the target value of the reaction force applied to the steering shaft is corrected by the speed calculated by the speed calculating unit. It is characterized by that.

  In the fourth aspect of the invention, since the reaction force corresponding to the steering speed of the steering member is applied to the steering shaft in addition to the steering angle of the steering member, the steering feeling is improved.

  According to a fifth aspect of the invention, the target reaction force determination unit applies the reaction force applied to the steering shaft based on the difference between the steering angle acquired by the steering angle acquisition unit and the bending angle between the front vehicle body and the rear vehicle body. The target value is determined.

  In the fifth aspect of the invention, since the reaction force is applied to the steering shaft based on the difference between the steering angle and the bending angle, the driver steers that the front vehicle body cannot follow the steering of the steering member. It can be recognized sensuously from the member.

  According to a sixth aspect of the present invention, the reaction force applying device further includes a change rate calculating unit that calculates a change rate of the difference between the steering angle and the bending angle, and the target value of the reaction force applied to the steering shaft is calculated as a change rate It is corrected by the rate of change calculated by the unit.

  In the sixth aspect of the invention, the target value of the reaction force applied to the steering shaft is further corrected by the change rate of the difference between the steering angle and the bending angle, so that the driver can change the follow-up delay of the front vehicle body. Can be recognized sensuously from the steering member.

  In a seventh aspect of the invention, the operating member is a swing lever, and the swing lever is provided with biasing springs for biasing the swing lever to the neutral position on both sides in the swing direction. .

  In the seventh invention, the biasing spring biases the swing lever to the neutral position. As a result, even if the reaction force applying device fails and cannot apply the reaction force to the steering shaft, the steering state can be sensibly recognized by the urging force of the urging spring.

  According to the present invention, it is possible to provide a hydraulic steering device in which a driver can feel a reaction force according to a steering state from an operation member.

FIG. 1 is a conceptual diagram of a work vehicle and a hydraulic steering device according to a first embodiment of the present invention. FIG. 2 is a conceptual diagram of the hydraulic steering device according to the first embodiment of the present invention. FIG. 3 is a block diagram of the controller according to the first embodiment of the present invention. FIG. 4 is a map stored in the controller according to the first embodiment of the present invention. FIG. 5 is a block diagram of a controller according to the second embodiment of the present invention. FIG. 6 is a map stored in the controller according to the second embodiment of the present invention. FIG. 7 is a block diagram of a controller according to the third embodiment of the present invention. FIG. 8 is a block diagram of a controller according to the fourth embodiment of the present invention. FIG. 9 is a map stored in the controller according to the fourth embodiment of the present invention. FIG. 10 is a block diagram of a controller according to the fifth embodiment of the present invention. FIG. 11 is a map stored in the controller according to the fifth embodiment of the present invention. FIG. 12 is a map stored in the controller according to the fifth embodiment of the present invention. FIG. 13 is a configuration diagram of a steering member of a hydraulic steering device according to a modification of the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment>
A hydraulic steering device 100 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

  The hydraulic steering device 100 is used, for example, in a work vehicle such as a so-called articulated wheel loader in which a front vehicle body and a rear vehicle body are rotatably connected via a connecting pin.

  As shown in FIG. 1, the work vehicle 10 includes a front vehicle body 11 to which a loader bucket 15 is attached, a rear vehicle body 12 that is swingably connected to the front vehicle body 11 by a pin 13 as a connection mechanism, A hydraulic steering device 100 that bends the vehicle body 11 with respect to the rear vehicle body 12 and a bending angle sensor 16 as a bending angle acquisition unit that acquires the bending angle θ between the front vehicle body 11 and the rear vehicle body 12 are provided. The rear vehicle body 12 is provided with a cabin having a driver's seat (not shown). The front vehicle body 11 and the rear vehicle body 12 each include a pair of wheels 14. The bending angle sensor 16 is provided in the vicinity of the pin 13.

  The hydraulic steering device 100 is driven by hydraulic pump 21 that supplies hydraulic fluid as a hydraulic fluid, and a pair of fluid pressures that are driven by the hydraulic fluid supplied from the pump 21 to swing the front vehicle body 11 with respect to the rear vehicle body 12. Hydraulic cylinders 22a and 22b as actuators, and a rotary control valve 23 that controls supply and discharge of hydraulic fluid supplied from the pump 21 to the hydraulic cylinders 22a and 22b are provided. The control valve 23 is provided on the rear vehicle body 12.

  The control valve 23 includes a supply port 23a communicating with the pump 21, a first cylinder port 23b communicating with a piston side chamber of the hydraulic cylinder 22a and a rod side chamber of the hydraulic cylinder 22b, a rod side chamber of the hydraulic cylinder 22a, and a piston of the hydraulic cylinder 22b. A second cylinder port 23 c that communicates with the side chamber and a discharge port 23 d that communicates with the tank 24 are provided.

  The control valve 23 includes an outer sleeve 23A that is rotatably accommodated in a valve body (not shown), and an inner sleeve 23B that is rotatably accommodated inside the outer sleeve 23A. The control valve 23 is configured such that the inner peripheral surface of the outer sleeve 23A and the outer peripheral surface of the inner sleeve 23B slide. By rotating the outer sleeve 23A and the inner sleeve 23B relative to each other, the control valve 23 has a neutral position A in which the supply port 23a and the discharge port 23d communicate with each other, and the first and second cylinder ports 23b and 23c are blocked. The switching position B where the supply port 23a and the second cylinder port 23c communicate with each other and the first cylinder port 23b and the discharge port 23d communicate with each other, the supply port 23a and the first cylinder port 23b communicate with each other, and the second cylinder port 23c and the discharge port 23d are switched to a switching position C.

  The inner sleeve 23B is connected to a steering wheel 1 as a steering member via a steering shaft 2 as a steering shaft. The outer sleeve 23 </ b> A is connected to the front vehicle body 11 via the link mechanism 20.

  The link mechanism 20 is a mechanism for feeding back the bending angle θ between the front vehicle body 11 and the rear vehicle body 12 to the control valve 23. Specifically, the link mechanism 20 rotates the outer sleeve 23 </ b> A according to the bending angle θ that the front vehicle body 11 is bent with respect to the rear vehicle body 12.

  As shown in FIG. 2, the steering shaft 2 includes an input shaft 3 to which steering torque is transmitted in conjunction with the steering wheel 1, an output shaft 4 having a lower end connected to the inner sleeve 23B, and the input shaft 3 and the output shaft. 4 and a torsion bar 5 connecting the four. Steering torque input to the steering wheel 1 by the operator's operation is transmitted to the output shaft 4 via the input shaft 3 and the torsion bar 5, and the inner sleeve 23B rotates together with the output shaft 4. A speed reducer may be provided between the output shaft 4 and the inner sleeve 23B.

  The hydraulic steering device 100 includes a steering angle sensor 6 as a steering angle acquisition unit that acquires the steering angle of the input shaft 3, and a steering torque sensor that detects a steering torque that acts on the torsion bar 5 when the steering wheel 1 is steered. 7 and a reaction force applying device 30 that applies a reaction force based on the steering angle acquired by the steering angle sensor 6. The reaction force applying device 30 is provided on the output shaft 4 of the steering shaft 2.

  Next, steering in the hydraulic steering device 100 will be described with reference to FIG. FIG. 1 shows a state in which the front vehicle body 11 is rotated rightward.

  First, a case where the work vehicle 10 is rotated to the right by a predetermined angle will be described. The driver steers the steering wheel 1 from the neutral state (the straight traveling state of the work vehicle 10) to the right. The rotation of the steering wheel 1 is transmitted to the inner sleeve 23B via the steering shaft 2. As a result, the inner sleeve 23B rotates relative to the angle outer sleeve 23A corresponding to the steering amount of the steering wheel 1, and the control valve 23 switches from the neutral position A to the switching position B.

  When the control valve 23 is switched to the switching position B, the hydraulic oil discharged from the pump 21 is supplied to the piston side chamber of the hydraulic cylinder 22a and the rod side chamber of the hydraulic cylinder 22b through the supply port 23a and the second cylinder port 23c. . At the same time, the hydraulic oil in the rod side chamber of the hydraulic cylinder 22a and the piston side chamber of the hydraulic cylinder 22b is discharged to the tank 24 through the first cylinder port 23b and the discharge port 23d. As a result, the hydraulic cylinder 22a extends and the hydraulic cylinder 22b contracts, so that the front vehicle body 11 moves so as to be bent in the right direction with respect to the rear vehicle body 12.

  As described above, the outer sleeve 23 </ b> A rotates according to the angle (bending angle θ) at which the front vehicle body 11 is bent with respect to the rear vehicle body 12. As a result, the relative angle between the outer sleeve 23A and the inner sleeve 23B gradually decreases as the hydraulic cylinder 22a expands, the hydraulic cylinder 22b contracts, and the bending angle θ approaches an angle corresponding to the steering amount of the steering wheel 1. Become. When the relative angle between the outer sleeve 23A and the inner sleeve 23B becomes 0 (zero), the control valve 23 returns to the neutral position A. In this way, the front vehicle body 11 rotates with respect to the rear vehicle body 12 in accordance with the steering amount of the steering wheel 1.

  Next, a case where the work vehicle 10 is rotated to the left by a predetermined angle will be described. The driver steers the steering wheel 1 from the neutral state (the straight traveling state of the work vehicle 10) to the left. The rotation of the steering wheel 1 is transmitted to the inner sleeve 23B via the steering shaft 2. As a result, the inner sleeve 23B rotates relative to the angle outer sleeve 23A corresponding to the steering amount of the steering wheel 1, and the control valve 23 switches from the neutral position A to the switching position C.

  When the control valve 23 is switched to the switching position C, the hydraulic oil discharged from the pump 21 is supplied to the rod side chamber of the hydraulic cylinder 22a and the piston side chamber of the hydraulic cylinder 22b through the supply port 23a and the first cylinder port 23b. . At the same time, the hydraulic oil in the piston side chamber of the hydraulic cylinder 22a and the rod side chamber of the hydraulic cylinder 22b is discharged to the tank 24 through the second cylinder port 23c and the discharge port 23d. As a result, the hydraulic cylinder 22a starts to contract, while the hydraulic cylinder 22b extends, so that the front vehicle body 11 moves to bend leftward with respect to the rear vehicle body 12.

  As described above, the outer sleeve 23 </ b> A rotates according to the angle (bending angle θ) at which the front vehicle body 11 is bent with respect to the rear vehicle body 12. As a result, the relative angle between the outer sleeve 23A and the inner sleeve 23B gradually decreases as the hydraulic cylinder 22a contracts, the hydraulic cylinder 22b extends, and the bending angle θ approaches an angle corresponding to the steering amount of the steering wheel 1. Become. When the relative angle between the outer sleeve 23A and the inner sleeve 23B becomes 0 (zero), the control valve 23 returns to the neutral position A. In this way, the front vehicle body 11 rotates with respect to the rear vehicle body 12 in accordance with the steering amount of the steering wheel 1.

  Since the steering wheel 1 and the front vehicle body 11 are not mechanically connected, when the front vehicle body 11 rotates with respect to the rear vehicle body 12, the operator receives the reaction force received by the wheel 14 of the front vehicle body 11. I cannot feel it from the steering wheel 1. For this reason, the hydraulic steering device 100 is provided with the reaction force applying device 30 so that the operator can feel the reaction force according to the steering state from the steering wheel 1. Below, the structure of the reaction force provision apparatus 30 is demonstrated, referring FIGS. 2-4.

  As shown in FIG. 2, the reaction force applying device 30 includes an electric motor 31 that applies a reaction force to the steering shaft 2, and first and second speed reducers that reduce and transmit the rotation of the electric motor 31 to the steering shaft 2. 32 and 33 and a controller 40 for controlling the electric motor 31. The electric motor 31 is a power source for applying a reaction force to the steering of the steering wheel 1 by the operator. The electric motor 31 is provided with a current sensor 9 that detects an applied current. The rotational torque output from the electric motor 31 is decelerated by the first and second reducers 32 and 33 and transmitted to the output shaft 4 of the steering shaft 2 as a reaction force. The first reduction gear 32 is a planetary gear type reduction gear, and the second reduction gear 33 is a worm reduction gear. Note that the speed reducer may be only the second speed reducer 33.

  Next, the controller 40 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram of the controller 40.

  The controller 40 temporarily stores a CPU that controls the operation of the electric motor 31, a ROM that stores a control program and a map necessary for the processing operation of the CPU, and information acquired by various sensors such as the steering angle sensor 6. RAM for storing.

  The controller 40 includes a target reaction force determination unit 41 that determines a target current I as a target value of the reaction force applied to the steering shaft 2 based on the steering angle acquired by the steering angle sensor 6, and a target reaction force determination unit. And a motor control unit 42 that controls the current applied to the electric motor 31 based on the target value determined by 41. The target reaction force determination unit 41 stores a map shown in FIG. 4 in advance.

  A steering angle acquired by the steering angle sensor 6 is input to the target reaction force determination unit 41. The target reaction force determination unit 41 determines a target current I corresponding to the input steering angle based on the map shown in FIG. 4 and outputs the target current I to the motor control unit 42.

  The map shown in FIG. 4 shows the relationship between the steering angle acquired by the steering angle sensor 6 and the target current I. In the map shown in FIG. 4, the target current I changes proportionally according to the magnitude of the steering angle. Specifically, the target current I increases to the negative side as the steering angle increases in the right direction. Conversely, the target current I increases to the positive side as the steering angle increases in the left direction. When the target current I is negative, the electric motor 31 generates a reaction force that rotates the steering shaft 2 in the left direction. When the target current I is positive, the electric motor 31 moves the steering shaft 2 to the right. A reaction force that rotates in the direction is generated.

  The motor control unit 42 includes a proportional / integration unit 43 for performing PI control, and a drive control unit 44 for controlling a current applied to the electric motor 31. The proportional / integral unit 43 calculates the driving target current by performing PI control on the deviation between the target current I and the current detected by the current sensor 9. The drive control unit 44 controls the current applied to the electric motor 31 based on the calculated drive target current.

  Next, a specific operation of the reaction force applying device 30 will be described.

  When the operator steers the steering wheel 1, the steering shaft 2 connected to the steering wheel 1 rotates. At this time, the steering angle sensor 6 acquires the rotation angle of the steering shaft 2, that is, the steering angle of the steering wheel 1, and outputs the acquired steering angle signal to the controller 40 (see FIGS. 2 and 3).

  In the target reaction force determination unit 41, the controller 40 determines the target current I from the input steering angle with reference to the map shown in FIG. The controller 40 controls the electric motor 31 so that the motor control unit 42 generates a reaction force corresponding to the target current I. The rotational torque output from the electric motor 31 is decelerated by the first and second reducers 32 and 33 and transmitted to the output shaft 4 of the steering shaft 2 as a reaction force. Further, this reaction force is transmitted to the steering wheel 1 connected to the steering shaft 2. Thereafter, the current flowing through the electric motor 31 is acquired by the current sensor 9 to perform feedback control.

  In the hydraulic steering device 100, the target current I increases as the steering angle of the steering wheel 1 increases. That is, the reaction force increases as the steering angle of the steering wheel 1 increases. As a result, when the operator steers the steering wheel 1, a reaction force corresponding to the steering angle acts on the steering wheel 1, so that the steering angle of the steering wheel 1 is sensibly recognized. Can do.

  According to the above 1st Embodiment, there exist the following effects.

  In the hydraulic steering device 100, the reaction force applying device 30 applies a reaction force to the steering shaft 2 based on the steering angle acquired by the steering angle sensor 6. As a result, the operator can feel a reaction force according to the steering state from the steering wheel 1. That is, the steering feeling is improved. Moreover, the magnitude of the steering angle of the steering wheel 1 can be sensibly recognized by changing the reaction force in proportion to the steering angle.

  In the hydraulic steering device 100, the reaction force is always generated by the reaction force applying device 30 when the steering wheel 1 is in a position other than the neutral position. That is, the reaction force applying device 30 always urges the steering wheel 1 toward the neutral position. Therefore, after steering the steering wheel 1, the operation of returning to the neutral state can be performed with a small force. Further, since the neutral state of the steering wheel 1 is easily maintained, the straight traveling performance of the work vehicle 10 can be ensured.

Second Embodiment
A hydraulic steering device according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the hydraulic steering of 1st Embodiment, and description is abbreviate | omitted.

  In the first embodiment, the target current I is determined based on the steering angle acquired by the steering angle sensor 6, but in the second embodiment, in addition to this, the target current I is determined according to the vehicle speed acquired by the vehicle speed sensor 8. Thus, the target current I is determined, which is different from the first embodiment.

  The work vehicle 10 is provided with a vehicle speed sensor 8 as a vehicle speed acquisition unit that acquires the speed of the work vehicle 10. The speed of the work vehicle 10 acquired by the vehicle speed sensor 8 is input to the controller 140. The controller 140 includes a target reaction force determination unit 141 that determines a target current I of reaction force applied to the steering shaft 2 according to the steering angle acquired by the steering angle sensor 6 and the vehicle speed acquired by the vehicle speed sensor 8. . In the target reaction force determination unit 141, a map shown in FIG. 6 is stored in advance.

  The map shown in FIG. 6 shows the relationship between the steering angle acquired by the steering angle sensor 6 and the target current I. Furthermore, the map shown in FIG. 6 has characteristics corresponding to low speed, medium speed, and high speed. For each characteristic corresponding to low speed, medium speed, and high speed, the target current I changes proportionally according to the magnitude of the steering angle. Specifically, the target current I increases to the negative side as the steering angle increases in the right direction. Conversely, the target current I increases to the positive side as the steering angle increases in the left direction. When the target current I is negative, the electric motor 31 generates a reaction force that rotates the steering shaft 2 in the left direction. When the target current I is positive, the electric motor 31 moves the steering shaft 2 to the right. A reaction force that rotates in the direction is generated.

  The characteristic corresponding to the medium speed is set such that the ratio of the change in the target current I to the change in the steering angle is smaller than that corresponding to the low speed. For this reason, even if the steering angle is the same, a smaller reaction force is applied at a medium speed than at a low speed. The characteristic corresponding to the high speed is set so that the ratio of the change in the target current I to the change in the steering angle is further smaller than the characteristic corresponding to the medium speed. For this reason, even if the steering angle is the same, a smaller reaction force is applied at high speed than at medium speed.

  The target reaction force determination unit 141 selects one of the characteristics of low speed, medium speed, and high speed according to the vehicle speed acquired by the vehicle speed sensor 8. Further, the target reaction force determination unit 141 determines the target current I from the steering angle acquired by the steering angle sensor 6 with reference to the selected characteristic. In FIG. 6, the characteristics of low pressure, medium pressure, and high pressure are stepwise, but the characteristics may be continuously changed.

  The target current I determined in this way is input to the motor control unit 42. Since the control of the electric motor 31 by the motor control unit 42 is the same as in the first embodiment, description thereof is omitted.

  According to the second embodiment described above, the following effects are obtained in addition to the effects of the first embodiment.

  The reaction force applying device 30 applies a reaction force based on the steering angle acquired by the steering angle sensor 6 and the vehicle speed of the work vehicle 10 acquired by the vehicle speed sensor 8 to the steering shaft 2. Thereby, in addition to the steering angle of the steering wheel 1, a reaction force corresponding to the vehicle speed is applied to the steering shaft 2, so that the steering feeling is improved.

<Third Embodiment>
A hydraulic steering device according to a third embodiment of the present invention will be described with reference to FIG. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the hydraulic steering of 1st Embodiment, and description is abbreviate | omitted.

  In the third embodiment, a steering torque sensor 7 that detects a steering torque that acts between the steering wheel 1 and the reaction force applying device 30 in the steering shaft 2 is provided, and the electric motor 31 has a difference between the target current I and the steering torque. It is different from the said 1st Embodiment by the point controlled based on.

  As described above, the torsion bar 5 is provided between the input shaft 3 to which the steering torque is transmitted in cooperation with the steering wheel 1 and the output shaft 4 whose lower end is coupled to the inner sleeve 23B ( (See FIG. 2). When a reaction force is applied to the steering shaft 2 by the electric motor 31 while the operator is steering the steering wheel 1, torque (twist) is generated in the torsion bar 5. This torque (hereinafter referred to as “steering torque”) is detected by the steering torque sensor 7. The steering torque corresponds to the reaction force actually felt when the operator steers the steering wheel 1. The reaction force applied to the steering shaft 2 by the electric motor 31 based on the target current I may be reduced due to mechanical loss before being transmitted to the steering wheel 1. That is, the reaction force that the operator feels from the steering wheel 1 may be smaller than the target reaction force. Therefore, the controller 240 feedback-controls the electric motor 31 based on the difference between the target current I and the steering torque so that the reaction force felt by the operator from the steering wheel 1 matches the target reaction force. Thereby, the reaction force felt by the operator from the steering wheel 1 can be matched with the target reaction force. A specific configuration will be described below.

  As shown in FIG. 7, the controller 240 subtracts the steering torque detected by the steering torque sensor 7 from the target current I. That is, the controller 240 calculates the difference between the target current I and the steering torque. The controller 240 performs P control in the proportional unit 246 on the difference between the target current I and the steering torque, and inputs the final target value to the motor control unit 42. Note that the control of the electric motor 31 by the motor control unit 42 is the same as in the first embodiment, and thus the description thereof is omitted. In addition, although P control was implemented in the proportional part 246, PI control and PID control may be sufficient.

  According to the above 3rd Embodiment, in addition to the effect of 1st Embodiment, there exist the following effects.

  The electric motor 31 targets the reaction force that the driver feels from the steering wheel 1 based on the difference between the target current I determined by the target reaction force determination unit 41 and the steering torque detected by the steering torque sensor 7. Controlled to match the reaction force. Thereby, the target reaction force can be reliably applied to the steering shaft 2.

<Fourth embodiment>
A hydraulic steering device according to a fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the hydraulic steering of 1st Embodiment, and description is abbreviate | omitted.

  The fourth embodiment is different from the first embodiment in that the controller 340 includes a speed calculation unit 345.

  As shown in FIG. 8, the controller 340 further includes a speed calculation unit 345 that calculates the steering speed of the steering wheel 1 based on the steering angle detected by the steering angle sensor 6.

  The speed calculation unit 345 calculates the steering speed of the steering wheel 1 from the change in the steering angle per unit time.

  The speed calculation unit 345 stores a map shown in FIG. 9 in advance. The speed calculation unit 345 determines a speed compensation current Is according to the calculated steering speed of the steering wheel 1 based on the map shown in FIG.

  The map shown in FIG. 9 shows the relationship between the calculated steering speed of the steering wheel 1 and the speed compensation current Is. In the map shown in FIG. 9, the speed compensation current Is changes in proportion to the steering speed. Specifically, in a state where the steering wheel 1 is steered rightward, the speed compensation current Is increases to the negative side as the steering speed increases. Conversely, in a state where the steering wheel 1 is steered leftward, the speed compensation current Is increases to the positive side as the steering speed increases. When the speed compensation current Is is negative, the electric motor 31 generates a reaction force that rotates the steering shaft 2 in the left direction. When the speed compensation current Is is positive, the electric motor 31 Generates a reaction force that rotates the to the right.

  The speed compensation current Is determined in this way is added to the target current I and input to the motor control unit 42. In other words, the target current I is corrected by the speed compensation current Is and input to the motor control unit 42. Thereby, in addition to the steering angle of the steering wheel 1, a reaction force corresponding to the steering speed of the steering wheel 1 is applied to the steering shaft 2. Note that the control of the electric motor 31 by the motor control unit 42 is the same as in the first embodiment, and thus the description thereof is omitted.

  According to the above 4th Embodiment, in addition to the effect of 1st Embodiment, there exist the following effects.

  The target current I of the reaction force applied to the steering shaft 2 is corrected by the speed compensation current Is calculated by the speed calculation unit 345. Therefore, in addition to the steering angle of the steering wheel 1, a reaction force corresponding to the steering speed of the steering wheel 1 is applied to the steering shaft 2, so that the steering speed can be recognized from the steering wheel 1 sensuously. Specifically, for example, when the steering speed of the steering wheel 1 is high, the rotation of the front vehicle body 11 may not follow the steering of the steering wheel 1. In such a case, the reaction force applied to the steering shaft 2 is increased so that the driver can recognize that the steering speed is fast, and the steering of the front vehicle body 11 may not follow. It can be recognized.

<Fifth Embodiment>
A hydraulic steering apparatus according to a fifth embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the hydraulic steering apparatus 100 of 1st Embodiment, and description is abbreviate | omitted.

  In the first embodiment, the target current I is determined based on the steering angle acquired by the steering angle sensor 6. However, in the fifth embodiment, the steering angle and bending angle sensor 16 acquired by the steering angle sensor 6. The second embodiment is different from the first embodiment in that the target current I is determined based on the angle difference from the bending angle obtained by the above and the target current I is corrected based on the rate of change of the angle difference.

  As shown in FIG. 10, the bending angle acquired by the bending angle sensor 16 is input to the controller 440. The controller 440 determines the target reaction I for determining the target current I of the reaction force applied to the steering shaft 2 based on the angle difference between the steering angle acquired by the steering angle sensor 6 and the bending angle acquired by the bending angle sensor 16. A force determination unit 441. The target reaction force determination unit 441 stores a map shown in FIG. 11 in advance.

  The target reaction force determination unit 441 receives an angle difference between the steering angle acquired by the steering angle sensor 6 and the bending angle acquired by the bending angle sensor 16. The target reaction force determination unit 441 determines a target current I corresponding to the input angle difference based on the map shown in FIG.

  The map shown in FIG. 11 shows the relationship between the angle difference between the steering angle and the bending angle and the target current I. In the map shown in FIG. 11, the target current I changes proportionally according to the magnitude of the angle difference. Specifically, in a state where the steering wheel 1 is steered rightward, the target current I increases toward the negative side as the angle difference between the steering angle and the bending angle increases. Conversely, in a state where the steering wheel 1 is steered leftward, the target current I increases to the positive side as the angle difference between the steering angle and the bending angle increases. When the target current I is negative, the electric motor 31 generates a reaction force that rotates the steering shaft 2 in the left direction. When the target current I is positive, the electric motor 31 moves the steering shaft 2 to the right. A reaction force that rotates in the direction is generated.

  The controller 440 further includes a change rate calculation unit 442 that calculates the change rate of the angle difference between the steering angle and the bending angle. The change rate calculation unit 442 calculates the change rate of the angle difference from the change of the angle difference per unit time.

  The change rate calculation unit 442 stores a map shown in FIG. The change rate calculation unit 442 determines a change rate compensation current Ir according to the calculated change rate of the angular difference of the steering wheel 1 based on the map shown in FIG.

  The map shown in FIG. 12 shows the relationship between the calculated change rate of the angle difference and the change rate compensation current Ir. In the map shown in FIG. 12, the change rate compensation current Ir changes proportionally according to the magnitude of the steering speed. Specifically, in a state where the steering wheel 1 is steered in the right direction, the change rate compensation current Ir increases toward the negative side as the change rate increases. Conversely, in a state where the steering wheel 1 is steered leftward, the change rate compensation current Ir increases to the positive side as the change rate increases. When the change rate compensation current Ir is negative, the electric motor 31 generates a reaction force that rotates the steering shaft 2 in the left direction. When the change rate compensation current Ir is positive, the electric motor 31 is rotated. Generates a reaction force that rotates the steering shaft 2 in the right direction.

  The target current I determined by the target reaction force determination unit 441 is added to the change rate compensation current Ir determined by the change rate calculation unit 442 and is input to the motor control unit 42. In other words, the target current I is corrected by the change rate compensation current Ir and input to the motor control unit 42. The corrected target current I is input to the motor control unit 42. Since the control of the electric motor 31 by the motor control unit 42 is the same as in the first embodiment, description thereof is omitted.

  Thus, by controlling the electric motor 31 based on the angle difference between the steering angle and the bending angle, the operator can feel a reaction force according to the angle difference from the steering wheel 1. Specifically, for example, when the work vehicle 10 is traveling in a muddy state, the front vehicle body 11 may not follow the steering of the steering wheel 1. In such a case, since the state where the angle difference between the steering angle and the bending angle is large is maintained, the reaction force applied to the steering shaft 2 is also maintained large. Accordingly, the operator can sensuously recognize from the steering wheel 1 that the front vehicle body 11 cannot follow the steering of the steering wheel 1.

  Further, when the target current I is corrected by the change rate compensation current Ir, the reaction force applied to the steering shaft 2 in the case where the follow-up of the front vehicle body 11 is further delayed with respect to the steering of the steering wheel 1. Becomes larger. Thereby, the operator can recognize from the steering wheel 1 sensibly a further delay in following.

  According to the above 5th Embodiment, there exist the following effects.

  The target current I of the reaction force applied to the steering shaft 2 is determined based on the angle difference between the steering angle and the bending angle. Thereby, the operator can feel a reaction force according to the angle difference from the steering wheel 1 and can sensuously recognize whether or not the front vehicle body 11 is following when the steering wheel 1 is steered.

  Further, the reaction force target current I applied to the steering shaft 2 is corrected by the rate of change of the angle difference between the steering angle and the bending angle. As a result, the operator can sensuously recognize the change in the tracking delay from the steering wheel 1.

  The change rate calculation unit 442 further improves the accuracy of the reaction force and is not an essential configuration.

  Note that the target current I in the fifth embodiment may be determined based on the vehicle speed of the work vehicle 10 as in the second embodiment. Further, the target current I in the fifth embodiment is configured to control the electric motor 31 based on the difference between the target current I and the steering torque detected by the steering torque sensor 7 as in the third embodiment. May be.

  In the first to fifth embodiments, the steering wheel 1 in which the steering member is a rotary type has been described as an example. However, the steering member may be a swing lever as shown in FIG. Below, the modification using the rocking lever 51 is demonstrated.

  In the modification shown in FIG. 13, biasing springs 52 that bias the swing lever 51 to the neutral position are provided on both sides in the swing direction. Thereby, when the swing lever 51 is steered, a reaction force acts on the swing lever 51 by the biasing spring 52. Therefore, even if the reaction force applying device 30 breaks down and cannot apply the reaction force to the steering shaft 2, the reaction force is applied by the urging force of the urging spring 52. The state can be recognized sensuously.

  The configuration, operation, and effect of the embodiment of the present invention configured as described above will be described together.

  The hydraulic steering device 100 is driven by the working fluid supplied from the pump 21, and swings the front vehicle body 11 with respect to the rear vehicle body 12 in accordance with the operation amount of the steering member (the steering wheel 1 and the swing lever 51). A steering angle acquisition unit (steering angle sensor) for acquiring a steering angle of a steering shaft (steering shaft 2) coupled to a fluid pressure actuator (hydraulic cylinders 22a, 22b) and a steering member (steering wheel 1, swing lever 51) 6) and a reaction force applying device 30 that applies a reaction force to the steering shaft (steering shaft 2) in a direction opposite to the steering direction. The reaction force applying device 30 includes the steering shaft (steering shaft 2). ) And a steering shaft (steering shaft) based on the steering angle acquired by the steering angle acquisition unit (steering angle sensor 6). Target reaction force determination units 41, 141, 441 for determining a target value (target current I) of reaction force to be applied to the shaft 2), and the electric motor 31 has target reaction force determination units 41, 141, 441. Control is performed based on the target value (target current I) determined by the above.

  According to this configuration, a reaction force is applied to the steering shaft (steering shaft 2) by controlling the electric motor 31 based on the steering angle acquired by the steering angle acquisition unit (the steering angle sensor 6). As a result, the operator can feel a reaction force according to the steering state from the steering shaft (steering shaft 2), so that the steering feeling is improved.

  Further, the hydraulic steering apparatus 100 is characterized in that the target value (target current I) of the reaction force applied to the steering shaft (steering shaft 2) is determined according to the vehicle speed of the work vehicle 10.

  According to this configuration, the steering shaft (steering shaft 2) is provided with a reaction force corresponding to the vehicle speed in addition to the steering angle of the steering member (steering wheel 1, swing lever 51). improves.

  The hydraulic steering device 100 also detects a steering torque 7 that detects a steering torque that acts between the steering member (the steering wheel 1 and the swing lever 51) and the reaction force applying device 30 on the steering shaft (the steering shaft 2). The electric motor 31 is controlled based on the difference between the target value (target current I) determined by the target reaction force determination units 41, 141, 441 and the steering torque detected by the steering torque sensor 7. It is characterized by being.

  In this configuration, the electric motor 31 is controlled based on the difference between the target value (target current I) determined by the target reaction force determination units 41, 141, 441 and the steering torque detected by the steering torque sensor 7. Thus, the reaction force acting on the steering shaft (steering shaft 2) can be applied with high accuracy.

  The hydraulic steering device 100 further includes a speed calculation unit 345 that calculates the speed of the steering member (the steering wheel 1 and the swing lever 51), and the target value of the reaction force applied to the steering shaft (the steering shaft 2). The (target current I) is corrected by the speed calculated by the speed calculation unit 345.

  According to this configuration, the steering shaft (steering shaft 2) has a steering speed of the steering member (steering wheel 1, swing lever 51) in addition to the steering angle of the steering member (steering wheel 1, swing lever 51). Since the corresponding reaction force is applied, the steering feeling is improved.

  In the hydraulic steering device 100, the target reaction force determination unit 441 includes the steering angle acquired by the steering angle acquisition unit (the steering angle sensor 6), the bending angle θ between the front vehicle body 11 and the rear vehicle body 12, and The target value (target current I) of the reaction force applied to the steering shaft (steering shaft 2) is determined based on the difference between the two.

  According to this configuration, since the reaction force is applied to the steering shaft (the steering shaft 2) based on the difference between the steering angle and the bending angle θ, the driver can operate the steering member (the steering wheel 1, the swing lever 51). ) That the front vehicle body 11 cannot follow the steering of the steering wheel (steering wheel 1, swing lever 51).

  In the hydraulic steering device 100, the reaction force applying device 30 further includes a change rate calculating unit 442 that calculates the change rate of the difference between the steering angle and the bending angle, and is applied to the steering shaft (steering shaft 2). The reaction force target value (target current I) is corrected by the change rate calculated by the change rate calculation unit 442.

  Since the target value of the reaction force applied to the steering shaft (steering shaft 2) is corrected by the rate of change of the difference between the steering angle and the bending angle, the driver can detect the change in the tracking delay by the steering member (steering wheel). 1. It can be recognized sensuously from the swing lever 51).

  The operating member is a swing lever 51, and the swing lever 51 is provided with biasing springs 52 for biasing the swing lever 51 to the neutral position on both sides in the swing direction. .

  According to this configuration, even if the reaction force applying device 30 breaks down and cannot apply the reaction force to the steering shaft (steering shaft 2), the steering state can be sensed sensuously by the urging force of the urging spring 52. Can be recognized.

  The controls in the first to fifth embodiments can be combined as appropriate. In the above embodiment, the control valve 23 is described as a rotary type. However, as long as the control valve 23 has a configuration capable of feeding back the bending angle θ, the control valve 23 may be of other types such as a spool type or a poppet type. May be. Further, the control valve 23 may be used as a pilot valve. In this case, a control valve for controlling the hydraulic cylinders 22 a and 22 b is separately provided, and the pilot pressure of the control valve is controlled by the control valve 23. Further, when the control valve 23 is used as a pilot valve, a pilot pump that supplies hydraulic oil to the control valve 23 may be separately provided in addition to the pump 21.

  In the map in each embodiment, an upper limit may be provided for the target current I. Thereby, reaction force is not provided excessively. In each embodiment, the target current I may be determined by calculation without using a map.

  Further, the maps shown in FIGS. 4 and 6 have such characteristics that the same reaction force is generated when the steering direction is the right direction and the left direction, but the characteristics may be different between the right direction and the left direction. . For example, since the swing lever 51 is normally operated with one hand, the reaction force felt by the operator is sensuously different between the right direction and the left direction (the pushing direction and the pulling direction). Therefore, as described above, by making the characteristics different between the right direction and the left direction, the reaction force can be felt as having the same level in the right direction and the left direction (the pushing direction and the pulling direction).

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

DESCRIPTION OF SYMBOLS 100 ... Hydraulic steering device, 1 ... Steering wheel (steering member), 2 ... Steering shaft (steering shaft), 5 ... Torsion bar, 6 ... Steering angle sensor (steering angle acquisition unit) ), 7 ... steering torque sensor, 8 ... vehicle speed sensor (vehicle speed acquisition unit), 9 ... current sensor, 10 ... work vehicle, 11 ... front vehicle body, 12 ... rear vehicle body , 13 ... Pin (coupling mechanism), 16 ... Bending angle sensor, 21 ... Pump, 22a, 22b ... Hydraulic cylinder (fluid pressure actuator), 23 ... Control valve, 30 ... Reaction force applying device, 31 ... electric motor, 40, 140, 240, 340, 440 ... controller, 41, 141, 441 ... target reaction force determination unit, 42 ... motor control unit, 51. ..Oscillating lever (steering part Material), 52 ... biasing spring, 345 ... speed calculation unit, 442 ... change rate calculation unit

Claims (7)

A hydraulic steering device for steering a work vehicle having a front vehicle body and a rear vehicle body swingably connected to the front vehicle body by a connection mechanism,
A fluid pressure actuator driven by a working fluid supplied from a pump and swinging the front vehicle body with respect to the rear vehicle body according to an operation amount of a steering member;
A steering angle acquisition unit for acquiring a steering angle of a steering shaft coupled to the steering member;
A reaction force applying device that applies a reaction force in a direction opposite to the steering direction with respect to the steering shaft,
The reaction force applying device is:
An electric motor for applying a reaction force to the steering shaft;
A target reaction force determination unit that determines a target value of the reaction force applied to the steering shaft based on the steering angle acquired by the steering angle acquisition unit;
The hydraulic steering device according to claim 1, wherein the electric motor is controlled based on the target value determined by the target reaction force determination unit.   The hydraulic steering apparatus according to claim 1, wherein the target value of the reaction force applied to the steering shaft is determined according to a vehicle speed of the work vehicle. A torque sensor for detecting a steering torque acting between the steering member and the reaction force applying device on the steering shaft;
The electric motor is controlled based on a difference between the target value determined by the target reaction force determination unit and the steering torque detected by the torque sensor. The hydraulic steering device described in 1. The reaction force applying device further includes a speed calculation unit that calculates the speed of the steering member,
4. The hydraulic system according to claim 1, wherein the target value of the reaction force applied to the steering shaft is corrected by the speed calculated by the speed calculation unit. 5. Steering device.   The target reaction force determination unit is a reaction force applied to the steering shaft based on a difference between the steering angle acquired by the steering angle acquisition unit and a bending angle between the front vehicle body and the rear vehicle body. The hydraulic steering device according to any one of claims 1 to 4, wherein the target value is determined. The reaction force applying device further includes a change rate calculation unit that calculates a change rate of a difference between the steering angle and the bending angle,
6. The hydraulic steering apparatus according to claim 5, wherein the target value of the reaction force applied to the steering shaft is corrected by the change rate calculated by the change rate calculating unit. The operating member is a swing lever,
The hydraulic type according to any one of claims 1 to 6, wherein the swinging lever is provided with biasing springs that bias the swinging lever to a neutral position on both sides in the swinging direction. Steering device.

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