JPH04108039A - Power vehicle - Google Patents

Abstract

PURPOSE:To prevent a front wheel side from running thoughtlessly at a high speed during low speed work so as to improve safety by correlating a suitable detector, which detects a running car speed, to a front wheel side acceleration switching machine in a manner wherein acceleration of the front wheel side is invalidated caused by the running car speed increased to a predetermined high speed or more. CONSTITUTION:In the case of performing farming work by mounting a work machine to a tractor, high speed work such as running on a road is not normally performed. Accordingly, a subtransmission 7 is shifted to a low speed side to place a main transmission 6 in an intermediate or low speed. Here, by reading a rotational speed of an input gear 16 of a car speed detecting part by a detector 18, its detection signal is input to a CPU20 through an A/D converter circuit. When a running speed is increased to a high speed, a switch of an acceleration switching mechanism 14 is controlled off by the CPU20 to excite a solenoid based on the rotational speed of the gear 16 detected by the detector 18. In this way, rotation in a side of a front wheel 2 is maintained to a stance of acceleration inability.

Description

[Detailed Description of the Invention] Industrial Application Field This invention includes a rear wheel side transmission system and a front wheel side transmission system,
A first driving state in which the rotational circumferential speed of the front wheel side and the rotational circumferential speed of the rear wheel side are the same, and a second drive state in which the rotational circumferential speed of the front wheel side is higher than the rotational circumferential speed of the # & wheel side. The present invention relates to a power vehicle equipped with a front wheel speed increasing mechanism that can be switched between two states.

BACKGROUND ART Conventionally, as seen in Japanese Utility Model Application Publication No. 60-62127, the turning speed is increased by increasing the rotational circumferential speed of the front wheels than the rotational circumferential speed of the rear wheels.

Some vehicles have a safety mechanism that does not switch the front wheels to high speed only when the sub-shift is operated at high speed.

Problems to be Solved by the Invention In the prior art, the front wheel high speed switching does not occur due to the driver's intention to switch between high speed, medium speed, and low speed in the overall high speed. Even if the vehicle is running at a low speed, if the engine throttle causes the vehicle to increase in speed, a situation where the front wheels are at high speed may occur, creating the risk of the vehicle rolling over during a turn.

In other words, the prior art has a safety mechanism that ignores the true vehicle speed, which poses a risk of causing a serious accident.

Means to solve problems This invention aims to solve the above problems.

A first drive state in which a transmission system for the rear wheel side and a transmission system for the front wheel side are provided, and the rotational circumferential speed of the front wheel side and the rotational circumferential speed of the rear wheel side are approximately the same, and the rotational circumferential speed of the rear wheel side. In a self-propelled vehicle equipped with a front wheel side speed increase switching mechanism 14 capable of switching to a second state in which the rotational peripheral speed of the front wheel side becomes extremely large, an appropriate vehicle speed can be detected. A power vehicle characterized in that a vehicle speed detector 18 and the front wheel side speed increase switching mechanism 14 are connected so that speed increase on the front wheels is disabled when the traveling vehicle speed becomes higher than a predetermined speed. And so.

Functions and Effects of the Invention According to the present invention, a detector that can detect the actual vehicle speed prevents the front wheels from going into a high speed state. ! Even if a situation arises in which the vehicle speed increases in the dark, the front wheels will
It is extremely safe as there is no speed increase.

That is, the present invention has been able to eliminate the conventional dangerous situation by using a technical means that prevents the front wheels from being in a high speed state due to the automatic element of substantially increasing the vehicle speed.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 denotes an agricultural tractor which is an example of a vehicle, and a pair of left and right front wheels 2, 2 and a pair of left and right rear wheels 3, 3. It has the following. A suitable working machine can be attached to the rear of the tractor 1 with the ability to raise and lower the tractor.

Further, both the front wheels 2, 2 and the rear wheels 3, 3 are configured to be driven via a transmission system. To explain the transmission system in detail, transmission is transmitted from the engine 4 via the main clutch 5 to the main transmission 6 and the auxiliary transmission 7 to the first output shaft 8, and from the first output shaft 8 to the rear wheel differential mechanism 9. through rear wheel 3
, 3 axles 10.10 are arranged for transmission. In addition, a second output from the 18th force shaft 8 via the deceleration mechanism 11! 12 is transmitted, and the power is transmitted to the front wheel differential mechanism 13. A speed increase switching mechanism 14 is interposed in the middle of transmission of the second output shaft 12. This speed increase switching mechanism 14 is configured to switch from a low speed rotation state to a high speed rotation state using a solenoid S, so that the same rotation of the front wheel drive output side shaft 8a is changed between high and low speeds. . The front wheel differential gear 4!1113 is transmitted from this shaft 8a, and the axles 15.15 of the front wheels 2, 2 are transmitted.

The electric circuit for energizing and de-energizing the solenoid S of the speed increase switching mechanism 14 will be explained starting from an example in which the same rotation speed of the shaft of the front wheel side rotation system is detected in 4 when the vehicle speed of the first implementation is detected. .

A permanent magnet 617 is embedded in the outer circumference of the input gear 16 of the speed reduction mechanism 11, for example, in the mesh -k 16a to impart magnetic force, and a permanent magnet 17 is provided at a fixed position on the rotational circumference of the wheel 16. A magnetic force detector 18 is provided to detect when M 16 a rotates.

The AID conversion circuit 19 converts the pulses of Magnetic Kai No. 3 that are intermittently detected by this detector 18, and extracts an output current from the C)'TJ (control unit) 20. When a current exceeding a certain level flows, the switch 1 The solenoid S is actuated via the solenoid S to switch the speed increase switching mechanism 14. Fifth
Symbols in the electrical control circuit in the figure: 22 is a key switch, 23
is the main switch.

24 is a manual switch for immediate running of rear wheel 2, which cuts off front wheel drive; 25 is a steering switch;
1IiS when the cutting angle of 2 is cut larger than the specified value.
It is a switch that changes the state.

That is, to explain the operation of the first embodiment first, when carrying out agricultural work in a field by attaching a working machine such as a rotary or a plow to the tractor 1 as a vehicle, high-speed work such as driving on the road is normally not possible. Don't do it. therefore,
The work is carried out by shifting the sub-transmission device 7 to a low speed side using a change lever (not shown) and setting the main transmission device 6 to a medium or low speed. At this time, the input gear 16 of the vehicle speed detection section
The rotation speed of C is read by the detector 18, and the detection signal is extracted as a current value by the A/D conversion circuit 19.
FIJ2. It is input to O. Then, the switch 21 is turned off and the solenoid SL is activated by a control signal generated inside the CPU.

That is, when the transmission rotational speed to the rear wheel side and the front wheel side is substantially below a certain rotational range, the switch 21 is set to r, the solenoid S is kept energized, and the rotation speed of the front wheel side can be increased. You will need to maintain a good posture. That is, the speed increase switching mechanism 14 maintains the speed increased switching state.

Therefore, when the steering switch 25 is energized when the steering wheel is operated to turn and the turning angle of the front wheels 2°2 is turned larger than a predetermined value, the speed increase switching mechanism 14 is in the speed increase state and the rear wheel is turned. The rotational circumferential speed of the front wheels 2, 2 becomes considerably larger than the rotational circumferential speed of the wheels 3, 3, resulting in a so-called double-speed turning state, which increases the turning speed and improves work efficiency.

However, when working with the main transmission side set to medium or high speed, the engine 4 is often set to high speed by operating the throttle when turning. In this case, the traveling speed becomes high even if the sub-shift is changed to a low speed. Even in such a case, since the rotation speed of the gear 16 is constantly read by the detector 18, the CPU 2
0, a command is issued to turn off the switch 21, and the solenoid S is energized.

Therefore, the rotation of the front wheels is maintained in a position in which it is impossible to increase the speed. That is, the activation switch 22 of the speed increase switching mechanism 14 is maintained in a disconnected state.

Therefore, even if the steering switch 25 is turned by operating the steering wheel and the turning angle of the front wheels 2.degree. The running condition is maintained in which the circumferential speed and the rear wheel side circumferential speed are approximately the same speed, and safe turns can be made without allowing sudden turns when turning.

Next, another example 2 will be described.

In the case of the second embodiment, the rotation speed of the drive shaft of the power transmission system to the front wheels or the rear wheels is not directly detected, but is detected from the rotation speed of the engine 7.

In order to detect the rotation of the engine, it is appropriate to detect the power generation of the generator 26 (alternator) which is directly transmitted from the engine 4, and when the voltage of the generator 26 exceeds a certain voltage, All you have to do is cut the high-speed drive state of the front wheel drive.

That is, the rotation of the engine 4 is normally controlled manually using a throttle lever, but during work, the engine horsepower is used at or above the rated level.

However, when driving on the road or in straight-line work in ordinary fields, the horsepower consumption is small and there is no need to increase the horsepower above the rating; on the other hand, increasing the horsepower beyond the rating causes a lot of noise and is not effective in terms of fuel efficiency. Therefore, it is extremely logical and effective control to perform front wheel speed increase/cut control by detecting the power generation state due to the power generation of 41$26.

For this purpose, in this second embodiment, the solenoid S of the first embodiment described above is used as the electric control circuit in FIG. It is the voltage sensor for machine 26. That is, when the voltage generated by the rotation of the generator 26 exhibits the characteristics shown in FIG. When "off", the solenoid S is de-energized and the speed increase switching mechanism 14 is configured to be in a low speed switching state.

Also in this second embodiment, as described above, when the engine throttle is set to a working speed close to fully open, the generated voltage exceeds a predetermined voltage, and this is detected by the detector 18a, preventing the front wheels from entering a high speed state. Since the speed increase switching mechanism 14 is switched in this manner, a safe state can be maintained.

[Brief explanation of drawings]

The figures show one embodiment of the present invention. Fig. 1 is a side view of an agricultural tractor as an embodiment of the vehicle, and Fig. 2 is a diagram showing its transmission mechanism. Fig. 3 is a side sectional view of the main parts, Fig. 4 is a rear view of the main parts, Fig. 5 is a simplified electrical circuit diagram, Fig. 6 is a simplified electrical circuit diagram of another example, and Fig. 6 is a simplified electrical circuit diagram of another example. Figure 7 is a diagram showing the performance of the generator. In the figure, symbol 14 indicates a front wheel side speed increase switching mechanism, and 18 indicates a detector.

Claims (1)

[Claims] A first drive state in which a transmission system for the rear wheel side and a transmission system for the front wheel side are provided, and the rotational circumferential speed of the front wheel side and the rotational circumferential speed of the rear wheel side are approximately the same, and the rotational circumferential speed of the rear wheel side. In a self-propelled vehicle equipped with a front wheel side speed increase switching mechanism 14 that can be switched to a second drive state in which the rotational circumferential speed of the front wheel side is significantly increased,
An appropriate vehicle speed detector 18 capable of detecting the traveling vehicle speed and the front wheel side speed increase switching mechanism 14 are connected so that the front wheel speed increase becomes invalid due to the traveling vehicle speed becoming higher than a predetermined speed. A powered vehicle characterized by: