JPH02147435A - Device for restraining high-speed backing of power vehicle - Google Patents

Abstract

PURPOSE:To enable high speed backing when necessary and greatly improve operation efficiency by operating the releasing means of a restraining means for switchover from high-speed advancing to backing when engine speed becomes below a defined value. CONSTITUTION:When an auxiliary transmission is being switched over to a high speed side, a relay R2 is in an operating condition while a relay R5 is in a nonoperating condition and, at this time, a throttle lever or pedal is returned to a low speed side to lower the engine speed of an engine 2 below a prescribed engine speed. When the engine speed is lowered below the prescribed value, an engine speed detecting device 50 detects this and an engine speed judging device 52 is operated to operate the relay R2 while further operating the relay R5. As the relay R5 is operated, the relay R2 which has been operated hitherto is returned to a nonoperating position and, therefore, as a backing pusher 43b is pushed in this condition, a machine body can be backed. Once the machine body is backed, this condition can be maintained even if the engine speed of the engine 2 is increased after that.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high-speed reversing restraint device for a power vehicle such as a tractor having a single forward/reverse switching device.

[Prior Art] Conventionally, in a power vehicle such as a tractor, a forward/reverse switching device is connected in series to a transmission consisting of a main transmission and an auxiliary transmission, and by operating this forward/reverse switching device, the vehicle can be driven at approximately rotational speed. There is something that tries to move the aircraft forward and backward.

In such a power vehicle, if the transmission is switched to a high-speed state, when the forward/reverse switching device is switched from the forward side to the reverse side, the operator will receive a considerable shock, which may lead to an unexpected accident. There is a risk of inviting For this reason,
As described in Publication No. 70827, when the forward/reverse switching device is switched to the reverse side while the transmission is switched to a high speed state, the transmission is automatically switched to the lower speed side by one gear. Alternatively, as described in Japanese Utility Model Application Publication No. 60-103027, the transmission is switched to a neutral state.

[The problem that the invention seeks to solve 1IJ11However,
In the above-mentioned conventional apparatus, even if the operator attempts to reverse at high speed, the restraint mechanism end is working, so the operator is unable to reverse at high speed, and work efficiency may deteriorate on the contrary.

[Means for Solving the Problems] The present invention is proposed in view of the above-mentioned problems, and takes the following technical measures.

In other words, the transmission device 7 that is capable of changing multiple speeds in the traveling system
．． 8 and a forward/reverse switching device 6 for switching the traveling direction of the aircraft in series, a detector 5o for detecting the rotational speed of the engine 2 and a means for checking switching from high-speed forward movement to reverse movement of the aircraft. and a release means for releasing the production control means, and the release means is configured to be activated when the rotational speed of the engine 2 falls below a predetermined value. composition.

[Example] Hereinafter, the present invention will be described in detail based on the drawings.

First, to explain the structure, reference numeral 1 is a tractor, in which an engine 2 is mounted on the front part of the machine body, and a clutch housing 3 and a transmission case 4 are sequentially connected to the rear part of the engine 2. A main clutch 5 is provided in the clutch housing 3, and a forward/reverse switching device 6 for switching the direction of movement of the aircraft, and a hydraulic main transmission 7 capable of shifting in four stages are provided inside the transmission case 4. , a hydraulic sub-transmission device 8 capable of two-speed shifting are provided in series in this order.

Next, the hydraulic circuit will be explained. As shown in the hydraulic circuit diagram in Fig. 2, the hydraulic oil sent out from the hydraulic pump 11 enters the diverter valve 12, where the hydraulic oil is transferred to A for lifting and lowering the working machine and B for shifting.
It is divided into two parts. Reference numeral 13 denotes a pressure increase control valve, and the pressure of the hydraulic oil passing through this control valve 13 is controlled in accordance with the current value passed to the solenoid 14. When this solenoid 14 is demagnetized, a hydraulic clutch 19 for forward and backward movement, which will be described later,
．． A portion of the hydraulic oil is sent to 20 as lubricating oil. Reference numeral 15 denotes a control valve for forward/reverse switching, which normally maintains a neutral position, and when the left solenoid 16a is energized, the forward hydraulic clutch 19 is held in the connected state, and the right solenoid 16b is energized. The reverse hydraulic clutch 20 is connected. Further, the hydraulic fluid branched from between the boost control valve 13 and the forward/reverse switching control valve 15 is sent to the control valves 22, 23, and 24 on the main transmission 7 and auxiliary transmission 8 sides. 27, 28, 29, 30 are respectively 1st speed, 2nd speed, 3rd speed,
This is a 4-speed solenoid. 31 is a high-speed side solenoid for sub-shifting, and 32 is a low-speed solenoid. -1
- Each of the control valves 22.23.24 maintains a neutral state under normal conditions, and the solenoid 27.2 of each control valve 22.23.24
When 8.29.30.31.32 is excited, the oil passage is switched and the gear shifting piston rod 33.34.35 is moved in the longitudinal direction of the piston rod 33.34.35.

The main transmission 7 and the auxiliary transmission 8 are switched to desired shift positions. The gear change of the main and sub-transmission devices 7 and 8 is as follows.

This is done by appropriately operating pushbutton switches 42a, 42b, . . . on an operation panel 41 provided next to the cockpit 40. Similarly, push button switch 4 also switches forward and backward.
This is done by operating 3a and 43b.

Next, the control system of this device will be explained based on the electric circuit shown in FIG.

Each push button switch 42a, 42 from 1st speed to 4th speed
b, 42c, 42d are delay circuits 46a, 46b, 4, respectively.
Relays 47a, 47b, 47c, via 6c, 46d,
47d, and further connected to respective relays 47a and 47b.
, 47c, 47d are solenoids 27.28.29.30
It is connected to the. 'r' is a timer, and R, , R, , are relays with two contacts. When the forward push button switch 43a or the reverse push button switch 43b of the forward/reverse switching device 6 is pressed, the contacts of the inactive relay R are closed, so the forward solenoid 16a or the reverse solenoid IGb is energized. Then, either the forward or reverse hydraulic clutch 19, 20 is connected. Furthermore, when any of the switches 42a, 42b, 42c, 42d of the main transmission 7 from 1st to 4th speed is operated, the timer T1 is activated and the previously connected forward or reverse Hydraulic clutch for 19.
20 is shut off for a predetermined period of time. At the same time, the main transmission 7 is activated by the solenoid (27
, 28, 29, 30) is excited. This is done in consideration of the fact that there is a time delay before the hydraulic clutches 19, 20 of the forward/reverse switching device 6 are actually disengaged. R1 is a 2-contact relay, R4, R6
is a relay. Also, in the same figure, 50 is the engine 2.
The rotation speed is a detector that detects the rotation speed of the motor, and when the detected rotation speed becomes equal to or lower than a predetermined low speed rotation speed, the rotation speed determination device 52 determines this and activates the relay R1.

Hydraulic auxiliary transmission.

When the high-speed push button switch 51a of No. 8 is pressed to turn on, the solenoid 31 of the sub-transmission device 8 is energized, and at the same time, the relay R2 is activated. Also.

When the low speed push button switch 51b is turned on,
Solenoid 32 is energized and relay R4 is activated at the same time.

Next, the effect will be explained. In the above configuration, when the aircraft is moving forward, the switches 42a and 42b of the main transmission 7
, 42c, or 42d, the timer T1 is activated, the relay R1 is activated, and the forward hydraulic clutch 19 is disengaged for the time set by the timer T□. There is a slight delay between the hydraulic oil in the hydraulic clutch 19 being drained and the hydraulic clutch 19 actually being disconnected, but the shift push button switch (42) of the main transmission 7
When one of a to 42d) is operated, the delay circuit (4
6a to 46d) is activated, and after a predetermined time delay, the shift solenoid (one of 27 to 30) is energized. When the sub-transmission device 8 is switched to the high-speed side, the relay R2 is activated, and when the sub-transmission device 8 is switched to the low-speed side, the relay R2 is kept in an inactive state. Even if the reverse push button switch 43b is turned on in an attempt to move one aircraft backward when the auxiliary transmission 8 is switched to the high speed side, the forward/reverse switching hydraulic clutch 6 is activated because the relay R is activated. The electric circuit leading to the reverse solenoid 16b is cut off, and therefore the aircraft cannot be moved backward. That is, no matter what shift position the main transmission 7 is at, as long as the sub-transmission 8 is switched to the high-speed side, the aircraft cannot be moved backwards.However, the low-speed push button switch 51b of the sub-transmission 8 When is turned on, the aircraft can be moved backwards.

Even when the sub-transmission device 8 is switched to the high speed side, the aircraft can be moved backward in the following cases. That is, when the auxiliary transmission 8 is switched to the high speed side, relay R2 is activated and relay R5 is inactive, but at this point, the throttle lever or pedal (not shown) is returned to the low speed side, and the rotational speed of the engine 2 is changed. When the rotation speed falls below a predetermined value, the rotation speed detector 50 detects this and the rotation speed discrimination device 52 is activated to activate relay R3, and then to activate relay R6. let The activation of relay R5 causes relay R2, which has been activated up to now, to return to its inoperative position, and therefore, in this state, the aircraft can be moved backward by pressing the reverse push button 43b.

As is clear from the explanation below, the auxiliary transmission 8 has been switched to the high speed side, and the reverse push button switch 43 has been switched to the high speed side.
Even when b is turned on, engine 2
By reducing the number of rotations below a predetermined value, the aircraft can be moved backwards. Once the aircraft moves backward, that state is maintained even if the rotational speed of the engine 2 increases by -1. In other words, the rotation speed of the engine 2 becomes 1 again.
- When the rotation speed determination device 52 increases, power is no longer supplied to relay R1, but power from relay R4 is supplied to relay R3, so relay R3 remains activated, and therefore the aircraft It is possible to move backwards at high speed. As is clear from the circuit diagram, the relay R3 is reset when the forward push button switch 43a is pressed or the low speed push button switch 51b of the auxiliary transmission 8 is turned on. In this embodiment, the relays R, , R, constitute a check means for checking the high-speed backward movement of the aircraft, and the relay R3, the rotation detector 50 of the engine 2, and the rotation speed discriminator 51 constitute a release means.

[Effects of the Invention] Since the present invention is configured as described above, it has the following technical effects. That is, when the speed change bag Fl17.8 is switched to the high-speed running state, the production control means is activated, so even if the operator unconsciously switches the forward/backward switching device 6 to the reverse side and attempts to move backward, the aircraft will not move backward. Therefore, as with the conventional device, the aircraft can be shifted safely. On the other hand, if the operator consciously tries to move the aircraft backwards at high speed from this state, the restraint can be released by simply operating the accelerator pedal or thrower 1 lever to reduce the rotation of engine 2 to a predetermined value or less. After that, if the operator increases the engine speed by 20 rpm again, the aircraft can be moved backwards at high speed. Efficiency can be greatly improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, with FIG. 1 being a side view of a tractor, FIG. 2 being a hydraulic circuit diagram, and FIG. 3 being an electrical circuit diagram. Explanation of symbols 1 Tractor 2 Engine main clutch transmission device 6 Forward/forward switching device 8 Sub-transmission device

Claims (1)

[Claims] 1) A transmission device 7 capable of switching multiple speeds in the driving system;
8 and a forward/reverse switching device 6 for switching the traveling direction of the aircraft in series, a detector 50 for detecting the rotational speed of the engine 2 and a means for checking the switching from high-speed forward movement to reverse movement of the aircraft. 1. A high-speed reversing restraint device for a power vehicle, comprising: and a release means for releasing the restraint means, and the release means is configured to operate when the rotational speed of the engine 2 falls below a predetermined value.