JPH032470Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a lock pin sensor that detects engagement and disengagement of a lock pin for fixing a hydraulic cylinder in a piston rod groove in a rear steering device and provides an alarm.

BACKGROUND ART For the purpose of improving steering stability at high speeds and reducing the turning radius, so-called rear steering devices have been considered that steer the rear wheels in addition to the normal front wheel steering. In such a rear steering device, the rear wheels are steered by a hydraulic cylinder for rear wheel steering, but when the rear wheels are not being steered, a lock pin is inserted into the groove of the piston rod of the hydraulic cylinder to rotate the piston rod. It was fixed in a neutral position. The piston rod was previously fixed by engaging and disengaging the piston rod with a groove using a lock pin, but the state of engagement and disengagement of the lock pin for switching rear wheel steering operation was achieved by sliding the lock pin. This was indicated by the operation of a switch installed on the side wall and end of the lock pin chamber (Utility Application No. 58-75447 (Utility Model Application No. 59-179756))
reference). However, because of this switch position, even if the lock state display disappeared, it could not be said that the lock pin had completely come out of the groove.
In addition, it could not be said that they were completely engaged.

Problems to be Solved by the Invention Therefore, according to the conventional structure described above, when switching the rear wheel steering operation, the lock display disappears even when the lock pin is not completely engaged with or disengaged from the piston rod groove. This was inconvenient because the lock pin or piston rod could be damaged if the rear wheel steering was performed assuming that the rear wheel steering was possible because the lock pin had disappeared.

In order to eliminate the above-mentioned disadvantages, the present invention improves the lock pin sensor so that it can detect the complete engagement state and the complete disengagement state of the lock pin.

Means for Solving the Problems The present invention solves the above-mentioned problems by penetrating a piston rod connected to the rear wheels through a hydraulic cylinder that performs rear wheel steering using hydraulic pressure, and engaging a lock pin in a groove of the piston rod. A rear steering device that locks and releases the rear wheels to a neutral position by disengaging the lock pin has a variable resistor whose resistance value changes according to the displacement of the lock pin, and A first threshold value for detecting an engagement completion state and a second threshold value for detecting a disengagement completion state are set for the detected output, and the output reaches the second threshold value. This lock pin sensor in a rear steering device is characterized in that it is configured to issue a warning that the rear wheels cannot be steered unless it is detected that the rear wheels have been steered.

Operation According to the above-mentioned means, the displacement of the lock pin is detected using a variable resistor whose resistance value changes continuously according to the displacement of the lock pin that locks and releases the lock to the neutral position of the rear wheel. Therefore, by detecting that the output detected from the variable resistor has reached a predetermined first or second threshold, it is possible to determine whether the lock pin is fully engaged or disengaged. Can be detected.

Embodiment An embodiment of the lock pin sensor in the rear steering device according to the present invention will be described based on FIGS. 1 and 2. As shown in FIG. A uniaxial piston rod 4 passes through the steering cylinder chamber 2, and a piston 5 is housed in the steering cylinder chamber 2, with the piston 5 being pivotally attached to the piston rod.In the lock cylinder chamber 3, a lock body 6 is pivotally attached to the piston rod. , the piston rod is provided with a locking groove 7. A lock pin 9 that engages and disengages from the groove 7 is arranged to be able to slide vertically within the lock pin chamber 8, and the lock pin 9 is connected to the spring 10.
The lock pin 9 is pushed up by the negative force and engaged with the groove 7, and the lock pin 9 is pushed down by the hydraulic pressure and disengaged from the groove 7. This lock pin 9 has a projecting portion 11 which is connected to a slider of a variable resistor 24.
As a result, the slider changes the resistance value of the variable resistor 24 in conjunction with the lock pin 9 which slides up and down under the bias of the spring 10 or hydraulic pressure, and the voltage that changes according to the resistance value is used as the measurement value. Continuously output. With respect to this voltage value, a first threshold value corresponding to the fully engaged state of the lock pin 9 and a second threshold value corresponding to the fully disengaged state of the lock pin 9 are set.
A threshold value is set, and unless it is detected that the output voltage value has reached the second threshold value, a warning is issued that the rear wheel steering is not possible. That is, lock pin 9
Since the displacement can be detected by the change in the voltage value constantly output from the variable resistor 24,
Not only the engagement completion state and disengagement completion state but also the intermediate state can be detected. Note that both lock bodies 6 of the lock cylinder chamber 3 are pressed by hydraulic pressure, and this pressure forms a neutral position for steering by the piston 5 of the steering cylinder chamber 2, and at that neutral position, the groove 7 of the lock part and the lock pin 9 are connected. The positions are configured to match.

The rear wheel steering hydraulic cylinder 1 as described above is disposed in a rear steering device as shown in FIG. That is, one side 14a of the hydraulic pump 14 driven by the engine 13 operates the front wheel steering gear box 15, and the other side 14b operates the front wheel steering gear box 15.
The steering controller 17 operates in response to a signal from the steering wheel angle sensor 16, and the control valve mechanism 18 is controlled by the steering controller 17 and supplied to the hydraulic cylinder 1, and the hydraulic pressure drives the piston rod 4. The drive causes the rear wheels to be steered via the parallel link 19 of the rear wheels. In addition, 20 is an accumulator, 21 is a handle, 22 is a reservoir, and 23 is a suspension.

Next, the operation of the lock pin sensor in the rear steering device having the above-mentioned configuration will be explained. When the rear steering device does not need to operate, the piston rod 4 is pressed by the lock body 6 that receives hydraulic pressure and is in the neutral position, as shown in FIG. The piston rod 4 is engaged with the piston rod 4 to lock the operation thereof. In this fully engaged state, the slider of the variable resistor 24 is located at the upper end, and the voltage set as the first threshold is output. When it becomes necessary to steer the rear wheels, the lock pin 9 is pushed down by hydraulic pressure and is disengaged from the groove 7. Further, at the same time as the lock pin 9 is pushed down, the protrusion 11 and the slider are also lowered together, and the voltage value output from the variable resistor 24 is detected in proportion to the change in resistance value. Therefore, the voltage value changes continuously from the first threshold value and reaches the second threshold value, but at the time the voltage set as the second threshold value is detected, the lock pin is The engagement of the piston rod 9 with the groove 7 is completely released, and even if the piston rod 4 operates, there is no interference with the lock pin 9, that is, the lock pin 9 has been completely disengaged. In this way, by detecting the second threshold value and detecting the disengagement completion state, the rear wheels become capable of steering for the first time, the alarm is canceled, and the control valve mechanism 18 receives the signal from the steering controller 17. The rear wheels are steered by the hydraulic pressure supplied to the hydraulic cylinder 1.

In addition, using the variable resistor 24, the lock pin 9
Since the displacement of the variable resistor 24 is detected, the output from the variable resistor 24 can always be obtained. Therefore, in the event of a complete failure, an output abnormality will occur, which can be immediately detected. Also, lock pin 9 and variable resistor 2
4 is always connected, so it has superior durability and reliability compared to using a contact type switch.

Effects of the invention According to the invention described above, the displacement of the lock pin is detected by the change in the voltage value constantly output from the variable resistor, and the voltage value has a first threshold indicating the engagement completion state. value and a second threshold value indicating the detachment completion state, and the output voltage value
The system is configured to detect that the lock pin has reached the threshold and determine that rear wheel steering is possible, so even if the lock display disappears, rear wheel steering is possible even if the lock pin is not completely removed. This eliminates the inconvenience caused by prying the lock pin. Furthermore, since displacement of the lock pin is continuously detected using a variable resistor, even if a complete failure occurs, it can be immediately detected from the abnormal voltage, resulting in a highly reliable and durable lock pin sensor. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rear wheel steering hydraulic cylinder showing an embodiment of the present invention, and FIG. 2 is an explanatory view of a rear steering device in which the hydraulic cylinder is arranged. 1...Hydraulic cylinder, 2...Steering cylinder room,
3... Lock cylinder chamber, 4... Piston rod, 5... Piston, 6... Lock body, 7... Groove, 8... Lock pin chamber, 9... Lock pin, 1
1...Protrusion, 14...Hydraulic pump, 16...Handle angle sensor, 17...Steering controller, 18...
Control valve mechanism, 24...variable resistor.

Claims (1)

[Scope of utility model registration request] The piston rod 4 connected to the rear wheels is passed through the hydraulic cylinder 1 that performs rear wheel steering using hydraulic pressure, and the lock pin 9 is engaged and disengaged from the groove 7 of the piston rod, thereby locking and releasing the rear wheels to the neutral position. This rear steering device has a variable resistor 24 whose resistance value changes according to the displacement of the lock pin, and a variable resistor 24 that detects an engagement completion state based on an output detected from the variable resistor. A threshold value 1 and a second threshold value for detecting a disengagement completion state are set, and unless it is detected that the output has reached the second threshold value, the rear wheel steering becomes possible. A lock pin sensor in a rear steering device, characterized in that it is configured to issue an alarm.