JPH06344807A - Traveling device of working vehicle - Google Patents

Abstract

PURPOSE:To avoid an engine stall on rising a stairs and a dangerous speed on descending to automatically adjust the speed within an appropriate range for both upward and downward directions and always the engine is driver at the rated revolution to drive a vehicle at a high efficiency and the driver's operation can be simplified. CONSTITUTION:This device is provided with a detector 8 for detecting the inclination of a vehicle body 1, a detector 9 for detecting the load on an engine 3, a first transmission Changing means 10 for setting the upper speed limit lower as the loading ratio is larger when the detected loading rate exceeds 50% and a second transmission Changing means 11 for setting the upper speed limit lower as the slant of the vehicle body is larger and the slope angle is more acute. When rising with a larger load, the speed is lowered in two stages to reduce the engine load and when descending with a smaller load, the vehicle speed is reduced more as the descending angle is more acute to avoid a dangerous speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling device for working vehicles such as emergency / rescue vehicles and baggage-carrying vehicles that can freely move up and down steep slopes and stairs.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an emergency vehicle or the like that can freely go up and down stairs to enter an underground mall in the event of a fire in an underground mall. The crawler, and the crawler is interlocked with a hydraulic transmission device called a so-called hydrostatic transmission having a hydraulic pump driven by an engine and a hydraulic motor driven by the hydraulic pump. It is possible to change the vehicle speed within a range of a vehicle speed upper limit value determined by adjusting a swash plate angle provided in a variable control element provided in the apparatus, that is, generally in a hydraulic pump.

[0003]

However, in the above, even if the driver lowers the vehicle speed upper limit value and adjusts to a low speed when entering the stairs from the flat ground and trying to climb the stairs, Depending on the inclination angle of the stairs and the weight of the load, the horsepower of the engine is insufficient on the way, and the engine speed drops sharply below the rated speed, causing a so-called engine stall. On the other hand, when trying to descend the stairs, even if the vehicle is adjusted to a low speed as well, there is a problem that the vehicle speed becomes unexpectedly high due to acceleration, which gives the driver a fear. In such a case, it is difficult and complicated for the driver to readjust the vehicle speed in the middle of the stairs.

An object of the present invention is to avoid an engine stall when ascending and avoid a dangerous speed when descending when going up and down a steep slope such as stairs, and to automatically adjust to an appropriate vehicle speed for both ascent and descent. However, it is another object of the present invention to provide a traveling device for a working machine capable of performing high-efficiency operation by rotating the engine at a rated speed and simplifying the operation.

[0005]

To achieve the above object, the machine body 1 is provided with a crawler 2 for traveling, and the crawler 2 is driven by a hydraulic pump 4 driven by an engine 3 and the hydraulic pump 4. A traveling device for a working vehicle, which is interlocked with a hydraulic transmission device 6 having a hydraulic motor 5 and is capable of changing a vehicle speed within a range of a vehicle speed upper limit value determined by adjusting a variable control element 7 provided in the hydraulic transmission device 6, A vehicle body inclination angle detecting means 8 for detecting the inclination of the vehicle body 1 with respect to the horizontal direction, a load factor detecting means 9 for detecting a load factor of the engine 3, and a vehicle speed upper limit value which is reduced when the detected load factor exceeds a predetermined value. The vehicle speed changing means 10 and the second vehicle speed changing means 11 for decreasing the vehicle speed upper limit value when the detector body inclination angle is large are provided.

[0006]

When the load factor of the engine 3 exceeds a predetermined value such as when going up a slope, the vehicle speed upper limit is reduced by the first vehicle speed changing means 10 and the rotation of the hydraulic motor 5, that is, the vehicle speed falls, but the hydraulic pump 4 And the engine 3 that drives it
Load is reduced. Further, when the vehicle is going up a slope or the slope is steep, the second vehicle speed changing means 11 further reduces the vehicle speed upper limit value, and the load on the engine 3 is further reduced. With these, stalling can be avoided.

On the other hand, when the load factor of the engine 3 falls below a predetermined value, such as when going down a slope, the second vehicle speed changing means 11 only adjusts the vehicle speed upper limit value. The second vehicle speed changing means 11 can reduce the vehicle speed upper limit value to avoid a dangerous speed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, reference numeral 1 denotes a machine body, and a drive wheel 21, a driven wheel 22, and a rolling wheel 2 are provided under the machine body 1.
3 and four traveling crawlers 2 having an endless belt 24. Further, the body 1 includes a pair of hydraulic pumps 4 driven by the engine 3 and four hydraulic motors 5 driven by the hydraulic pumps 4.
The hydraulic power transmission 6 having the above-described structure is provided, and each motor output shaft 51 in the hydraulic power transmission 6 is connected to each crawler 2 through an interlocking body 50 using sprockets 52, 53 and a chain 54.
It is interlocked with the drive wheel 21 of. In FIG. 2, 1
Reference numeral 0 is a driving cabin that is freely lifted and lowered via an elevator 12, 13 is a driving seat, 14 is a joystick for control,
Reference numeral 15 is a monitor.

Then, as shown in FIG. 1, a joystick controller 101 connected to the input side thereof is controlled by a control device 100 having a microcomputer.
According to the operation of the auxiliary shift volume 102, the variable control element 7 formed of a swash plate provided in each hydraulic pump 4 is angularly adjusted by current-controlling the control coil 70 of the swash plate angle control valve of the nozzle flapper type or the like. The vehicle speed can be changed within the range of the vehicle speed upper limit value determined by the inclination angle of the plate 7.

With the above structure, as shown in FIG.
In addition, a machine body tilt angle detection means 8 for detecting the tilt of the machine body 1 with respect to the horizontal direction is provided and is input to the control device 100. or,
The engine 3 includes an electronic governor controller 90 that maintains the engine speed at a rated value by adjusting the fuel injection amount by adjusting the throttle opening. The governor controller 90 is used to generate engine horsepower data or throttle opening. A load factor detection means 9 for detecting the load factor by inputting data to the control device 100 is provided.

Further, as shown in FIG.
The electronic governor controller 90
When the load factor detected based on the engine horsepower data (see FIG. 4) taken in from above exceeds a predetermined value, for example, when the load factor exceeds 0.5 (50%), the vehicle speed upper limit value is reduced to the value shown by the following equation. First vehicle speed changing means 10 is provided (steps a and b in FIG. 3).

Upper limit value of vehicle speed × (1-detection load factor) ... Further, the difference between the sensor output voltage (see FIG. 5) fetched from the machine body inclination angle detecting means 8 and a reference voltage indicating horizontal, for example, 2.5 volts. The larger the absolute value of, that is, the steeper the slope is for both the uphill slope and the downhill slope, the second vehicle speed changing means 11 that reduces the vehicle speed upper limit value according to the following formula is provided (steps c and d in FIG. 3).

Vehicle speed upper limit value × (1− | sensor output voltage−2.5 | ÷ 2.5) ... In this way, the load factor of the engine 3 is 0.5 (50%) when climbing a slope. When the vehicle exceeds the first vehicle speed changing means 10
As a result, the higher the load factor, the lower the vehicle speed upper limit value, and the rotation of the hydraulic motor 5, that is, the vehicle speed decreases, but the load on the hydraulic pump 4 and the engine 3 that drives the hydraulic pump 4 is reduced. Further, when the vehicle is going up a slope and the slope is steep, the second vehicle speed changing means 11 further reduces the vehicle speed upper limit value as the slope becomes steeper, thereby further reducing the load on the engine 3. As a result, the engine 3 can always be operated at the rated speed, and engine stalling can be avoided.

On the other hand, when the load factor of the engine 3 falls below 0.5 (50%), such as when going down a slope, the second vehicle speed changing means 11 only adjusts the vehicle speed upper limit value, and the downward slope is tight. In this case, the second vehicle speed changing means 11 can prevent the vehicle speed upper limit value from becoming smaller as the inclination becomes steeper, thereby avoiding a dangerous speed.

[0015]

As described above, according to the present invention, when going up and down a steep slope such as stairs, it is possible to avoid an engine stall when ascending and to avoid a dangerous speed when descending. , It can be automatically adjusted to an appropriate vehicle speed, the engine 3 can be rotated at a rated speed, and highly efficient driving can be performed, and the driver does not need to adjust the vehicle speed one by one in the middle of the hill. It can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a traveling device for a working machine according to the present invention.

FIG. 2 is a side view showing the overall structure of the working machine.

FIG. 3 is a flowchart showing vehicle speed control by the traveling device.

FIG. 4 is a diagram illustrating a relationship between engine speed and horsepower for explaining a load factor detection unit.

FIG. 5 is a diagram illustrating a relationship between a sensor output voltage and an angle, which illustrates a tilt angle detection unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Airframe, 2; Crawler, 3; Engine, 4; Hydraulic pump, 5; Hydraulic motor, 6; Hydraulic transmission device, 7; Variable control element, 8; Aircraft inclination angle detecting means, 9; Load factor detecting means,
10; first vehicle speed changing means, 11; second vehicle speed changing means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taiji Mizukura 1-32, Chayamachi, Kita-ku, Osaka, Osaka Prefecture Yanmar Agricultural Machinery Co., Ltd. (72) Wataru Nakagawa 1-32, Chaya-machi, Kita-ku, Osaka, Osaka No. Yanmar Agricultural Machinery Co., Ltd. (72) Inventor Ritsuko Kajioka 1-32 Chayamachi, Kita-ku, Osaka City, Osaka Prefecture Yanmar Agricultural Machinery Co., Ltd.

Claims (1)

[Claims] 1. A vehicle body (1) is provided with a crawler (2) for traveling, and the crawler (2) is driven by an engine (3) and a hydraulic pressure is driven by the hydraulic pump (4). Interlock with a hydraulic transmission (6) with a motor (5),
A traveling device for a working vehicle, the vehicle speed of which can be changed within a vehicle speed upper limit value determined by adjusting a variable control element (7) provided in the hydraulic power transmission (6). Airframe inclination angle detecting means (8) for detecting, and load factor detecting means (9) for detecting the load factor of the engine (3).
A first vehicle speed changing means (10) for decreasing the vehicle speed upper limit value when the detected load factor exceeds a predetermined value, and a second vehicle speed changing means (11) for decreasing the vehicle speed upper limit value when the detected body tilt angle is large. A traveling device for a working vehicle characterized by being provided.