JPH09217821A - Reflux oil control device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of defective lubrication due to insufficiency in oil by a method wherein reflux oil is fed to a necessary spot according to the inclination state of a machine body. SOLUTION: A tractor comprises an inclination sensor 40 to sense an inclination angle in a longitudinal direction wit the horizontal plane of a machine body; an electromagnetic switching valve 44 in which reflux oil fed to the respective parts of a machine body flows; and a microcomputer 48 to compute a destination of reflux oil according to the inclination angle of a machine body based on a detection signal from the inclination sensor 40 and switch and control the electromagnetic switch valve 44 according to the computing result. Reflux oil is returned to an oil insufficient spot and oil levels at inner parts of a transmission case 32 are held approximately at a constant value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle such as a tractor, and more particularly to a circulating oil control device for a work vehicle for driving and controlling a hydraulic control device such as a three-point link lifting device while circulating oil.

[0002]

2. Description of the Related Art In a work vehicle such as a tractor, oil stored in a lower portion of a transmission case is circulated between the transmission case and a hydraulic control device such as a three-point link lifting device and power steering, and the hydraulic control device is used. Is controlled and the oil level of each part in the transmission case is held substantially constant by the circulating oil.

By the way, conventionally, as shown in FIG. 5, the circulating oil from the hydraulic control device 60 into the transmission case 32 is, for example, a rear case 38 (a circulating oil from the power steering unit 50) which is predetermined through a pipe 46. In this case, it was returned to a certain place such as being returned to the front case 34).

[0004]

However, although the oil level in the entire transmission case 32 is normally equalized, if the airframe tilts forward or backward or left or right, there will be some oil shortages, and oil shortages will occur. May cause poor lubrication. In such a case,
It is conceivable to increase the amount of oil in advance and store it in the transmission case 32 in order to eliminate the oil shortage, but this not only increases the cost, but also causes a power loss due to an excessive amount of oil, an increase in the oil temperature, and the like. Defect occurs.

The present invention has been made to solve the above problems, and an object thereof is to feed circulating oil to a necessary place according to the tilted state of the machine body to cause poor lubrication due to insufficient oil. Another object of the present invention is to provide a circulating oil control device for a work vehicle capable of preventing the above.

[0006]

In order to achieve the above object, the present invention provides a transmission case (3
Oil stored in 2) is circulated between the hydraulic control device (60) and the transmission case (3).
In a work vehicle for driving and controlling the hydraulic control device (60) while keeping the oil level of each part in 2) substantially constant, a tilt sensor (40, 42) for detecting a tilt angle of the machine body (12) with respect to a horizontal plane. ), An import (44a) into which the circulating oil from the hydraulic control device (60) flows, and a pipe (4) guided to each part in the transmission case (32).
6) a plurality of outports (44b, 44c,
44d) and a switching valve (44) having a switching valve (44d), and an output destination of the circulating oil according to the tilt angle of the machine body (12) based on the detection signals from the tilt sensor (40, 42). A control means (48) for controlling switching of the switching valve (44) based on the switching valve (44).

(Operation) According to the present invention, when the machine body (12) is tilted in the front-rear direction in the present invention, there may be an oil-deficient portion in each part of the transmission case (32) which is particularly long in the machine front-rear direction. , The tilt angle of the fuselage (12) with respect to the horizontal plane at this time
0, 42), and based on the detection signal at this time,
The control means (48) calculates the output destination of the circulating oil according to the inclination angle of the machine body (12), and returns the circulating oil to the oil-deficient portion of each part.

In this case, the control means (48) controls switching of the switching valve (44) based on the calculation result to return the circulating oil to the oil-deficient portion of each part. The switching valve (44) Is an import (44a) into which the circulating oil from the hydraulic control device (60) flows, and a pipe (46) that is guided to each part in the transmission case (32).
To a plurality of outports (44b, 44c, 44)
d), and in response to a command from the control means (48), a specific outport is opened to supply circulating oil to the pipe (4).
Send to 6).

The reference numerals in the above parentheses are for the purpose of comparing the drawings, but do not limit the structure of the present invention.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of a tractor 10 as a work vehicle to which the present invention is applied.
0 indicates that the vehicle body 12 has front wheels 14, 14 and rear wheels 16,
A driver's seat 20 is provided which is supported by 16 and has a seat 22 at the front and an engine 18 at the center. On a side portion of the driver's seat 20, an operation lever 24 capable of swinging operation is provided.
And a clutch pedal and a brake pedal (not shown) are provided in step 28 below the steering wheel 26.

Further, below the step 28, the rotation of the engine 18 is continuously changed to change the speed of the rear wheels 16, 1.
Transmission 30 as a transmission device for transmitting to 6
It has.

As shown in FIG. 2, oil used as lubricating oil and hydraulic oil is stored in the lower part of the transmission case 32 that covers the outer peripheral portion of the transmission 30, and this oil is used as a three-point link lifting device. The hydraulic control device 60 is drive-controlled while circulating the hydraulic pressure control device 60 such as a power steering device or the like while keeping the oil level of each part in the transmission case 32 substantially constant.

The transmission case 32 has a front case 34, a middle case 36 and a rear case 38, and the front case 34 is directly connected to the engine 18.
The rear case 38 is fixed to the chassis. Further, the rear case 38 is provided with a constantly rotating PTO shaft 62, and the PTO shaft 62 drives the hydraulic pump. Oil circulated with the hydraulic control device 60 is stored in the lower portion of the transmission case 32.

Here, in the present invention, the inclination sensor for detecting the inclination angle of the machine body 12 with respect to the horizontal plane, the import into which the circulating oil from the hydraulic control device 60 flows in, and the pipes guided to the respective parts in the transmission case 32 are provided. And a switching valve having a plurality of communicating outports.

That is, in FIG. 2 described above, the body 1
Inclination sensors 40 and 42 that detect the inclination angle in the front-rear direction or the left-right direction with respect to the horizontal plane are provided at appropriate positions in 2, and when the body 12 tilts in the front-rear direction by moving on a sloping ground, for example, The oil level in the transmission case 32 having a long shape in the front-rear direction changes accordingly, and the tilt sensor 40 detects the tilt angle of the body 12 at that time.

Further, an import 44a into which circulating oil from the hydraulic control device 60 flows into the machine body 12 via a pipe 46a, a front case 34, a middle case 36, and a rear case 38 of the transmission case 32.
(Or a brake chamber, a rear axle case) An electromagnetic switching valve 44 as a switching valve provided with a plurality of out ports 44b, 44c, 44d communicating with a plurality of pipes 46b, 46c, 46d guided to respective parts is provided. There is.

Next, the present invention relates to the tilt sensor 4
Control means for calculating the output destination of the circulating oil according to the tilt angle of the machine body 12 based on the detection signals from 0 and 42, and controlling the switching of the switching valve 44 based on the calculation result.

That is, in FIG. 2 described above, the microcomputer 48 as the control means is based on the detection signals from the tilt sensors 40 and 42, and the body 12
Grasp the inclination of the aircraft with respect to the horizontal plane, and
The location where oil shortage will occur depending on the inclination angle of is stored in advance, and the output destination of the circulating oil is calculated based on the detection signal. Then, from the front case 34, the middle case 36, the rear case 38, etc., the output destination where the oil shortage occurs is selected based on the calculation result, and the electromagnetic switching valve 44 is switch-controlled according to the selected destination. The circulating oil is sent to the output destination.

In this way, even during the continuous tilting operation of the machine body 12, the entire oil level including the inside of the transmission case 32 is made uniform, and the occurrence of insufficient lubrication due to insufficient oil is prevented.

In this embodiment, the inclination sensor 40
Although the case where the inclination of the machine body 12 in the front-rear direction is detected has been described above, the same applies to the case where the inclination sensor 42 detects the inclination of the machine body 12 in the left-right direction.

Next, FIGS. 3 and 4 show an embodiment in which the power steering can be operated even when the engine of the tractor 10 is stopped.

In this embodiment, even if the pumps 56a and 56b are stopped by stopping the engine, by steering the steering wheel 26 to the left and right, oil is sucked from the steering column pipe 52 serving as a self-sufficient tank to steer the wheels. Power cylinders (right and left) 58 are operated to enable power steering of the front wheels 14.

That is, conventionally, a structure is provided in which a dedicated self-contained tank is provided or the circulating oil is returned to the oil level in the transmission case 32 as indicated by a broken line so that the pumps 56a and 56b do not suck air and cause a trouble. Therefore, it is difficult to utilize the circulating oil, but in this embodiment, the upper and lower portions of the steering column pipe 52 provided on the upper portion of the power steering unit 50 are sealed with oil seals 54, 54. As a result, since the steering column pipe 52 is used as a self-contained tank, it is not necessary to return the oil to the oil surface, and the circulating oil can be returned to a necessary position in the transmission case 32 to make the oil level uniform. .

Thus, the power steering unit 50
Oil discharged from the tank port T of the hose 55
The power steering unit 50 can be steered by turning the steering wheel 26 even when the engine is stopped.

Next, the operation of this embodiment will be described.

When the wheels of the tractor 10 are driven to travel, the inclination of the body 12 in the front-rear direction or the left-right direction with respect to the horizontal plane is constantly detected by the inclination sensors 40 and 42, and the detected value is detected by the microcomputer 48. It is remembered each time. On the other hand, the oil in the transmission case 32 is circulated between the transmission case 32 and the hydraulic control device 60 such as the power steering unit 50 and the three-point link lifting device.

By the way, for example, when the machine body 12 is inclined in the front-rear direction with respect to the horizontal plane, the transmission case 32 is long in the front-rear direction of the machine body. May be. Therefore, by storing in advance in the microcomputer 48 the location of the oil shortage that occurs depending on the tilted state, the microcomputer 48
Is based on the detection signals from the tilt sensors 40 and 42,
Calculate where oil is insufficient. The calculation result is sent to the electromagnetic switching valve 44, and the electromagnetic switching valve 44 controls the switching of the valve based on the command signal, and the hydraulic control device 6
Feed the reflux oil from 0 to the designated place.
As a result, it is possible to prevent a partial lack of oil from occurring, and prevent occurrence of poor lubrication.

[0029]

As described above, according to the present invention,
An inclination sensor that detects the inclination angle of the machine body with respect to the horizontal plane, a switching valve that controls the output destination of the circulating oil from the hydraulic control device, and a control unit that controls the switching valve based on the detection signal from the inclination sensor. By including the above, it is possible to prevent occurrence of poor lubrication due to insufficient oil even during continuous tilting operation. Also,
Since the oil can be returned to a high place, it is possible to lower the overall oil level, so even if the oil level is lowered, the lubrication function is improved, power loss can be reduced, and the oil amount can be reduced. Because it is less, it also leads to cost reduction.

[Brief description of drawings]

FIG. 1 is an external perspective view of a tractor to which the present invention is applied.

FIG. 2 is a diagram schematically showing the configuration of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a main part of another embodiment.

FIG. 5 is a diagram schematically showing a configuration of a conventional circulating oil control device.

[Explanation of symbols]

 10 Tractor 12 Aircraft 14 Front Wheel 16 Rear Wheel 26 Steering Wheel 30 Transmission 32 Transmission Case 34 Front Case 36 Middle Case 38 Rear Case 40, 42 Inclination Sensor 44 Electromagnetic Switching Valve 44a Import 44b to 44d Outport 46 Piping 48 Microcomputer

Claims (1)

[Claims] 1. The hydraulic control device is driven and controlled while the oil stored in the transmission case is circulated between the hydraulic control device and the hydraulic control device while keeping the oil level of each part in the transmission case substantially constant. In a work vehicle, it has an inclination sensor that detects the inclination angle of the machine body with respect to the horizontal plane, an import that the circulating oil from the hydraulic control device flows in, and a plurality of outports that communicate with piping that is led to each part in the transmission case. A switching valve, and a control means for calculating the output destination of the circulating oil according to the tilt angle of the machine body based on the detection signal from the tilt sensor, and controlling the switching of the switching valve based on the calculation result. A circulating oil control device for a work vehicle characterized by the above.