JPH06336123A - Traveling controller equipped with hydraulic pump for vehicle - Google Patents

Abstract

PURPOSE:To provide a traveling controller for a vehicle which is equipped with a pump which can carry out stable traveling even if one wheel idle- revolves. CONSTITUTION:A hydraulic pump 11 is driven by an enginne 12. The left and right driving wherls 13L and 13R of a vehicle are directly diiven by the hydraulic motors 14L and 14R for traveling. The hydraulic motors 14L and 14R are driven by the working oil supplied from the hydraulic pump 11. Solenoid valves 21a and 21b are installed in a conduit leading from the hydraulic pump 11 to the hydraulic motor 14L, and solenoid valves 22a and 22b are installed midway in the conduit leading from the hydraulic pump 11 to the hydraulic motor 14R. Revolution sensors 23L and 23R are installed on the motor shafts of the hydraulic motors 14L and 14R for traveling. A controller 24 judges the idle revolution of oen wheel from the difference of the number of revolution which is detected by the revolution sensors 23L and 23R, and solenoid valves 21a, 21b, 22a, and 22b on the hydraulic motors 14L and 14R sides for traveling in idling are opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control device equipped with a hydraulic pump, and more particularly to a travel control device for an engine vehicle equipped with a variable speed variable displacement hydraulic pump.

[0002]

2. Description of the Related Art Conventionally, various industrial vehicles such as forklifts have been proposed which are driven by a variable speed variable displacement hydraulic pump.

FIG. 3 shows a general structure of a traveling drive system in such an industrial vehicle. A swash plate type variable displacement hydraulic pump (hereinafter, abbreviated as hydraulic pump) 11 is driven by an engine 12. The swash plate (not shown) of the hydraulic pump 11 is driven by hydraulic oil supplied from a charge pump (not shown), and the tilt angle and the tilt direction of the swash plate change.
Therefore, the discharge capacity and discharge direction of the hydraulic oil discharged from the hydraulic pump 11 are controlled by the rotation speed of the engine 12 and the tilt angle and tilt direction of the swash plate.

The left and right drive wheels 13L and 13R of the vehicle are provided with traveling hydraulic motors 14L and 14R, respectively, and are directly driven. Then, each traveling hydraulic motor 14
L and 14R are driven by hydraulic oil supplied from the hydraulic pump 11.

Therefore, each traveling hydraulic motor 14L, 1
The rotation speed of 4R (that is, the rotation speed of each drive wheel 13L, 13R) is controlled by the discharge capacity of the hydraulic pump 11. Thereby, the traveling speed of the vehicle is controlled.

[0006]

By the way, when the industrial vehicle having the above-mentioned structure is run on a place where the ground contact state with respect to each drive wheel 13L, 13R is different (for example, on an uneven terrain or a frozen road), Only one of the drive wheels 13L and 13R may idle.

Then, the hydraulic oil discharged from the hydraulic pump 11 is supplied only to the traveling hydraulic motor 14L (or 14R) of the idling drive wheel 13L (or 13R). Therefore, the idling drive wheel 13L (or 13R) is finally idling, while the non-idling drive wheel 13R (or 13L) is not driven. As a result, the vehicle loses control and it is difficult to return by itself, so that stable running cannot be performed.

The present invention has been made to solve this problem, and an object thereof is to provide a travel control device for a vehicle equipped with a hydraulic pump capable of performing stable travel even if one wheel runs idle. To provide.

[0009]

In order to solve the above problems, the present invention is directed to a hydraulic pump and a first hydraulic pressure driven by hydraulic oil supplied from the hydraulic pump to drive a right drive wheel for traveling. A motor, a second hydraulic motor driven by hydraulic oil supplied from the hydraulic pump to drive the left drive wheel for traveling, and an idle rotation detecting that one of the left and right drive wheels is idle. When the idling detecting means detects that the detecting means and one of the left and right drive wheels are idling, the hydraulic circuit independent means for making the hydraulic circuit of the first hydraulic motor and the hydraulic circuit of the second hydraulic motor independent. The gist of the provision of and.

[0010]

Therefore, according to the present invention, when one of the left and right drive wheels is idling, the idling detecting means detects it. Then, the hydraulic circuit independent means makes the hydraulic circuit of the first hydraulic motor and the hydraulic circuit of the second hydraulic motor independent.
As a result, even if one drive wheel remains idle, the other drive wheel that is not idle will be driven. Therefore, the vehicle does not lose control and can return by itself, which enables stable traveling.

[0011]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIG.

In the present embodiment, the same components as those in the conventional example shown in FIG. 3 are designated by the same reference numerals and detailed description thereof will be omitted. From the hydraulic pump 11 to the traveling hydraulic motor 14
Open / close switching electromagnetic valves (hereinafter abbreviated as valves) 21a and 21b are provided in the middle of the pipeline of the hydraulic oil supplied to L. Similarly, valves 22a and 22b are provided in the middle of the pipeline of the hydraulic oil supplied from the hydraulic pump 11 to the traveling hydraulic motor 14R.

The traveling hydraulic motors 14L and 14R are also provided.
Each motor shaft is provided with each rotation sensor 23L, 23R for detecting the rotation speed. And
The controller 24, based on the rotational speeds of the traveling hydraulic motors 14L and 14R detected by the rotational sensors 23L and 23R (that is, the rotational speeds of the drive wheels 13L and 13R), the valves 21a, 21b, 22a and 22b. Switch control.

Here, the controller 24 and the rotation sensor 2
3L and 23R constitute an idling detection means, and the controller 24 and the valves 21a and 21b constitute a hydraulic circuit independent means.

Next, the operation of this embodiment will be described. In normal traveling, the controller 24 controls the valves 21a,
21b, 22a and 22b are opened. As a result, the traveling hydraulic motors 14L and 14R are driven by the hydraulic oil supplied from the hydraulic pump 11, and the drive wheels 13L and 1R are driven.
3R is driven.

At this time, when the difference between the rotation speeds of the drive wheels 13L and 13R detected by the rotation sensors 23L and 23R exceeds a set value, the controller 24 causes the drive wheel 13L (or 13R) having the higher rotation speed to be detected. Is determined to be spinning. In addition, the set value is set when the vehicle is run in a place where the ground contact state with respect to the drive wheels 13L and 13R is different (such as an uneven ground or a frozen road), and only one of the drive wheels 13L and 13R is idling. It can be obtained by an experiment for obtaining the difference in rotation speed.

When the controller 24 determines that one of the drive wheels 13L (or 13R) is idling, the controller 24 determines that the valve 2 on the side of the drive wheel 13L (or 13R) is in motion.
1a and 21b (or 22a and 22b) are closed. Then, the drive wheel 13L (or 13
Supply of hydraulic oil to the traveling hydraulic motor 14L (or 14R) of R) is cut off, and the other drive wheel 13R (or 1
The hydraulic oil is supplied only to the traveling hydraulic motor 14R (or 14L) of 3L.

As a result, one drive wheel 13L (or 1
Even if (3R) remains idle, the other non-idling drive wheel 13L (or 13R) is driven. Therefore, the vehicle does not lose control and can return by itself, which enables stable traveling.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment differs from the first embodiment shown in FIG. 1 only in the following points. Therefore, the other components are given the same reference numerals, and detailed description thereof will be omitted.

1) In place of one hydraulic pump 11, two tandem pump types (31R, 31L) are provided. That is, each hydraulic pump 31
R and 31L are hydraulic pumps of the same standard and are integrally driven by the engine 12. Also, each hydraulic pump 3
Each of the swash plates 1R and 31L (not shown) is driven by hydraulic oil supplied from the same charge pump (not shown), and the tilt angle and the tilt direction of the swash plate change. Therefore, the discharge volumes and discharge directions of the hydraulic oil discharged from the hydraulic pumps 31R and 31L are the same, and are controlled by the rotation speed of the engine 12 and the tilt angle and tilt direction of the swash plate.

2) Valves 32a and 32b are provided between the oil feed lines of the hydraulic pumps 31R and 31L. That is, when both valves 32a and 32b are closed, the configuration is the same as that in which two hydraulic pumps 11 are provided in parallel in the conventional example shown in FIG. Also, both valves 32
When a and 32b are open, the hydraulic circuits of the traveling hydraulic motors 14R and 14L are independent. That is, when both valves 32a and 32b are open, the traveling hydraulic motor 14R is driven only by the hydraulic pump 31R, and the traveling hydraulic motor 14L is driven by the hydraulic pump 31L.
Only driven by.

3) The controller 24 controls each rotation sensor 2
Each hydraulic motor 14L, 1 for traveling detected by 3L, 23R
The valves 32a and 32b are switch-controlled based on the rotation speed of 4R (that is, the rotation speed of the drive wheels 13L and 13R).

Here, the controller 24 and the valve 32
The hydraulic circuit independent means is constituted by a and 32b. Next, the operation of this embodiment will be described.

During normal traveling, the controller 24
Keeps the valves 32a and 32b open. as a result,
The traveling hydraulic motors 14L and 14R are the respective hydraulic pumps 31.
The driving wheels 13L and 13R are driven by the hydraulic oil supplied from a and 31b.

At this time, when the difference between the rotation speeds of the drive wheels 13L and 13R detected by the rotation sensors 23L and 23R exceeds the set value, the controller 24 causes the drive wheel 13L (or 13R) having the higher rotation speed. ) Is determined to be spinning.

When the controller 24 determines that one drive wheel 13L (or 13R) is idling, the controller 24 closes both valves 32a and 32b. Then, the traveling hydraulic motor 14R is driven only by the hydraulic pump 31R, and the traveling hydraulic motor 14L is driven only by the hydraulic pump 31L. Therefore, each drive wheel 13L, 13
Each R will be driven independently.

As a result, one drive wheel 13L (or 1
Even if (3R) remains idle, the other non-idling drive wheel 13L (or 13R) is driven. Therefore, the vehicle does not lose control and can return by itself, which enables stable traveling.

The present invention is not limited to the above embodiment, but may be carried out as follows. (1) The rotation sensors 23L and 23R are omitted, and a flow meter that detects the flow rate of the hydraulic oil supplied to each of the traveling hydraulic motors 14L and 14R is provided. Then, the controller 24 determines that the drive wheel 13L (or 13R) having the larger flow rate is idling when the difference between the flow rates of the hydraulic oils supplied to the traveling hydraulic motors 14L and 14R exceeds the set value. To do.

(2) Swash plate type variable displacement hydraulic pumps 11, 3
Replace 1L and 31R with another type of variable displacement hydraulic pump or constant displacement hydraulic pump. (3) Replace the engine 12 with an electric motor.

(4) One drive wheel 13L (or 13
When R) idles, the rotation speed of the engine 12 is also controlled in addition to the above control. That is, the rotational speed of the engine 12 is appropriately increased according to the detected difference in rotational speed to increase the rotational speed of the drive wheel 13R (or 13L) that is not idling. Or, depending on the detected difference in rotational speed,
The rotational speed of the drive wheel 13R (or 13L) that is not idling is lowered by appropriately lowering the rotational speed of the engine 12.
This makes the traveling of the vehicle more stable.

[0031]

As described in detail above, according to the present invention, it is possible to provide a vehicle travel control device equipped with a hydraulic pump capable of performing stable travel even when one wheel runs idle. There is an effect.

[Brief description of drawings]

FIG. 1 is a hydraulic and electric circuit diagram of a first embodiment embodying the present invention.

FIG. 2 is a hydraulic and electric circuit diagram of a second embodiment embodying the present invention.

FIG. 3 is a hydraulic circuit diagram of a conventional example.

[Explanation of symbols]

11, 31L, 31R ... hydraulic pump, 13R ... right running drive wheel, 14R ... running hydraulic motor as first hydraulic motor, 13L ... left running drive wheel, 14L ... as second hydraulic motor Hydraulic motors for running, 21a, 2
1b, 32a, 32b ... Open / close switching electromagnetic valve, 23L,
23R ... Rotation sensor, 24 ... Controller

Claims (1)

[Claims] 1. A hydraulic pump, a first hydraulic motor driven by hydraulic oil supplied from the hydraulic pump, and driving a driving wheel on the right side, and a first hydraulic motor driven by hydraulic oil supplied from the hydraulic pump. A second hydraulic motor for driving the left drive wheel, a idle detection means for detecting that one of the left and right drive wheels is idle, and one of the left and right drive wheels If the idling detection means detects that the hydraulic circuit of the first hydraulic motor and the second
And a hydraulic circuit independent means for making the hydraulic circuit of the hydraulic motor independent of each other.