JPH0589154U - Front two-axle steering device - Google Patents

Abstract

(57) [Abstract] [Purpose] The maximum permissible steering angle in the case of mechanically steering the first and second axes of the front two axes by a link mechanism and hydraulically steering the first and second axes. The adjustment of the position stopper is simplified and the link mechanism is made smaller and lighter. [Structure] A stopper 10 and a maximum allowable steering angle detection limit switch 21 are provided on the first shaft. When the limit switch 21 detects that the front front wheel 6 has reached the maximum allowable steering angle, the first and second solenoid valves 19 and 20 are closed, and the oil supply to the hydraulic cylinder 15 of the second shaft is stopped. ..

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a steering device for steering a front two-axle in a front two-axle vehicle.

[0002]

[Prior Art]

 The following is a conventional example of a steering device for a front two-axle vehicle. That is, the steering force of the steering wheel is mechanically transmitted to the first shaft and the second shaft of the front two-axle vehicle via the link mechanism to steer each steered wheel, and the steering hydraulic cylinder of each steered wheel is controlled. Oil is supplied in synchronism with the mechanical operation of the steering wheel to assist the steering force.

Here, a stopper bolt is attached to the knuckle of each steered wheel, and when the steered wheel is steered to a maximum allowable steering angle, the stopper bolt is brought into contact with the stopper on the axle main body side so that the steered wheel is It is not possible to steer more than the maximum allowable steering angle (see "Maintenance truck in the maintenance manual" issued by Nissan Diesel Industry Co., Ltd. in April 1986).

[0004]

[Problems to be solved by the device]

 By the way, since the steered wheels of the first shaft and the second shaft are steered by the hydraulic mechanism at the same time as the mechanical operation by the link mechanism, the steering in which the stopper bolt contacts the stopper in the first shaft and the second shaft. If the angles are not adjusted to be the same, the stopper bolt of one shaft may not contact the stopper when the stopper bolt of one shaft contacts the stopper. For this reason, since the steered wheels are about to be steered by the hydraulic mechanism on the other shaft, an excessive force acts on the link mechanism, so that it is necessary to increase the strength of the link mechanism more than necessary. There is a problem that it becomes large. In order to solve this, the stoppers of the first shaft and the second shaft must be accurately adjusted, which makes the adjustment work complicated.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to simplify stopper adjustment, prevent an excessive force from acting on the link mechanism, and reduce the size of the link mechanism. To do.

[0006]

[Means for Solving the Problems]

 Therefore, in the present invention, a stopper portion for restricting the steering angle of the steered wheels to be within the maximum allowable steering angle is provided on one of the first shaft and the second shaft in the front two-axle vehicle and the steering angle of the steered wheels is Steering angle detecting means for detecting that the maximum allowable steering angle is reached is provided near the stopper portion, and the hydraulic type is used when the steering angle detected by the steering angle detecting means is the maximum allowable steering angle. An oil supply stopping means for stopping the oil supply to the drive device is provided.

[0007]

[Action]

 In this manner, the stopper portion is provided on one of the first shaft and the second shaft, and the steering angle detection means for detecting the maximum allowable steering angle position is provided, and the stopper adjustment is performed on one shaft. The simplification has been made, and when the steering angle reaches the maximum allowable steering angle, the oil supply to the hydraulic drive device is stopped so that no excessive force acts on the link mechanism.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, an intermediate portion between the first axis idler arm 1 and the second axis idler arm 2 of the front two axes in a work vehicle such as a crane truck is swingably attached to the vehicle body. One ends of the two are connected by a middle link 3. Further, one end of the first-axis drag link 4 and one end of the second-axis drag link 5 are swingably attached to the other ends of the idler arms 1 and 2, respectively. The other ends of the glinks 4 and 5 are swingably attached to steering arms 8 and 9 of the knuckles of the front front wheel 6 and the front and rear wheels 7, respectively. The left and right knuckles are connected by a tie rod (not shown).

Here, stopper bolts 10 are attached to both sides of the axle body of the first shaft, respectively, while stoppers (not shown) are formed in the knuckles of the front front wheels 6. The stopper comes into contact with the stopper bolt 10 when the front front wheels 6 are steered to the maximum allowable steering angle. Here, the stopper and the stopper bolt 10 form a stopper portion.

Further, one end portion of a link 11 is swingably attached to the other end side of the idler arm 1 for the first shaft, and the other end portion of the link 11 is a lever portion of a gear box 13 of a steering wheel 12. It is mounted so that it can swing freely. Then, the operating force of the steering wheel 12 is mechanically transmitted from the gear box 13 to the idler arm 1 for the first shaft via the link 11. On the first shaft side, the steering force is transmitted from the first shaft idler arm 1 to the steering arm 8 via the drag link 4 and the front front wheels 6 are steered. On the second shaft side, the steering force is transmitted from the first shaft idler arm 1 to the second shaft idler arm 2 via the middle link 3 and then to the steering from the idler arm 2 via the drag link 5. It is transmitted to the arm 9 and the front and rear wheels 7 are steered. Therefore, the idler arms 1, 2, the middle link 3, the drag links 4, 5, and the link 11 form a link mechanism.

A pair of return type steering first hydraulic cylinders 14 are attached to the axle body of the first shaft, and the piston rods of the first hydraulic cylinders 14 can freely swing on the knuckles of the left and right front front wheels 6. Are installed in each. A pair of return-type steering second hydraulic cylinders 15 are attached to the axle body on the second shaft side, and piston rods of the second hydraulic cylinders 15 are attached to the knuckles of the left and right front and rear wheels 7 so that they can swing freely. There is. Here, the first and second hydraulic cylinders 14 and 15 form a hydraulic drive device.

One of the hydraulic chambers of the first and second hydraulic cylinders 14 and 15 is connected to one port of an oil flow switching valve 17 via a first oil passage 16, and the first and second hydraulic cylinders 14 and 15 are connected to each other. The other hydraulic chambers of 15 and 15 are connected to the other port of the switching valve 17 through a second oil passage 18. A first solenoid valve 19 is provided in a first oil passage 16 for supplying oil to one hydraulic chamber of the second hydraulic cylinder 15 of the second shaft, and oil is supplied to the other hydraulic chamber of the second hydraulic cylinder 15 in the first hydraulic passage 16. A second solenoid valve 20 is provided in the second oil passage 18 for supply. The first and second solenoid valves 19 and 20 are opened when energized and closed when de-energized to close the oil passages 16 and 18. Therefore, the first and second solenoid valves 19 and 20 form oil supply stopping means.

Normally-closed limit switches 21 as steering angle detecting means are attached to both sides of the axle body of the first shaft along with the stopper bolt 10, and the front front wheels 6 are steered to the maximum allowable steering angle position. When the limit switch 21 is contacted, the contact of the limit switch 21 comes into contact with the contact of the front wheel 6 and the contact of the limit switch 21 is turned off. The limit switches 21 are connected in series, and the solenoids of the first and second solenoid valves 19 and 20 and the battery 22 are connected via the limit switches 21.

Reference numeral 23 is an oil pump as an oil supply device, and 24 is an oil tank. According to this structure, when the front front wheel 6 and the front and rear wheels 7 are steered at a steering angle smaller than the maximum allowable steering angle, both limit switches 21 are turned on. Since the first and second solenoid valves 19 and 20 are opened by being energized, oil is supplied to the second hydraulic cylinder 15 on the second shaft side through the first and second oil passages 16 and 18. Therefore, since oil is supplied through the steering wheels 16 and 18, the steering force of the steering wheel 12 is applied to the front front wheel 6 and the front and rear wheels 6 through the link mechanism such as the link 11, the idler arms 1 and 2, and the middle link 3. At the same time as being mechanically transmitted to the wheel 7, oil is supplied to the first and second hydraulic cylinders 14 and 15 to assist the steering force of the steering wheel 12.

When the front front wheel 6 and the front and rear wheels 7 are steered to the maximum allowable steering angle position, the knuckle stopper of the front front wheel 6 contacts the stopper bolt 10 and at the same time, the contact portion of one limit switch 21. The limit switch 21 is turned off. As a result, the first and second solenoid valves 19, 20 are de-energized and closed, and the first and second oil passages 16, 18 are closed, so that the second hydraulic cylinder of the second shaft is closed. Since the oil supply to 15 is stopped, the steering of the front and rear wheels 7 by the second hydraulic cylinder 15 is completed. As a result, the second hydraulic cylinder 15 does not steer the front and rear wheels 7 beyond the maximum allowable steering angle and no excessive force acts on the link mechanism, so the strength of the link mechanism can be kept lower than before. As a result, the link mechanism can be made smaller and lighter.

Further, since the stopper portion and the limit switch 21 are provided only on the first shaft, the stopper adjustment only needs to be performed on the first shaft, and the stopper adjustment can be easily performed. The stopper and the limit switch may be provided only on the second shaft. Further, the oil supply to the first and second hydraulic cylinders 14 and 15 may be stopped at the same time.

[0017]

[Effect of the device]

 As described above, the present invention provides the hydraulic drive device for providing the stopper portion and the means for detecting the maximum allowable steering angle on one of the first shaft and the second shaft, and for steering the steered wheels when the maximum allowable steering angle is detected. Since the oil supply to the engine is stopped, the stopper adjustment can be simplified and the link mechanism can be made smaller and lighter.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1,2 Idler arm 3 Middle link 4,5 Drag link 6 Steering wheel 7 Front and rear wheels 10 Stopper bolt 11 Link 12 Steering wheel 14 1st hydraulic cylinder 15 2nd hydraulic cylinder 19 1st solenoid valve 20 2nd solenoid valve 21 Limit switch

Claims (1)

[Scope of utility model registration request] 1. A steering force of a steering wheel is mechanically transmitted to a steering wheel of a first shaft and a steering wheel of a second shaft in a front two-axle vehicle through a link mechanism, and the first shaft and the second shaft are connected.
Steering of a front two-axle vehicle in which hydraulic drive devices for steering the steered wheels are respectively provided on the shaft and oil is supplied from the oil supply device to each hydraulic drive device substantially in synchronization with steering of the steering wheel. In the device, a stopper portion that restricts a steering angle of the steered wheels to be within a maximum allowable steering angle is provided on one of the first shaft and the second shaft, and the steering angle of the steered wheels is the maximum allowable steering angle. An oil supply for locating a steering angle detecting means for detecting the oil pressure is provided near the stopper portion, and for stopping the oil supply to the hydraulic drive device when the steering angle detected by the steering angle detecting means is the maximum allowable steering angle. A steering device for a front two-axle vehicle, characterized in that stop means is provided.