JPS6146777A - Automatic tension device for crawler - Google Patents

Abstract

PURPOSE:To give the specified tension to a crawler, by letting pressure oil, making an operating part go up and down, operate on an idler pushing hydraulic cylinder. CONSTITUTION:When a selector valve 17 is operated, pressure oil in a hydraulic pump 19 is fed to a reaping part lifting hydraulic cylinder 15 as well as fed to an idler pushing hydraulic cylinder 12 via a check valve 13, making an idler 9 move in its tension direction. And, when a reaping part goes up to the full and the hydraulic cylinder 15 extends as far as its stroke end, the pressure oil is relieved at a relief valve 21, whereby relief pressure consisting of the specified high pressure is fed to the idler pushing hydraulic cylinder 12. With this constitution, the idler 9 give its fixed pressing force to a crawler.

Description

Detailed Description of the Invention (a) Field of Industrial Application The present invention relates to an automatic crawler tensioning device used in working vehicles such as combines, and more specifically, a crawler tensioning device that uses hydraulic pressure to act on a working part such as a reaping part. Related to automatic tensioning equipment.

(B) Conventional Technology Conventionally, a crawler tensioning device has been constructed by connecting an idler to a bolt through a push rod, and manually tensioning the crawler by moving the idler by screwing in the bolt.

(c) Problems that the invention attempts to solve Because of this, it takes a lot of time to tension the crawler.

It is necessary and very troublesome, and it is difficult to maintain the tension in the optimum condition, resulting in tension.

In addition, if the crawler length increases over time, the idler position remains constant (unless manual adjustment is made), so the tension on the crawler is lost, and the N1 wheels, etc., get over the protrusion of the crawler, causing work in the field, etc. It often happened that the wheels would easily come off and become undriveable. Furthermore, since the idler is fixed in place with the bolt screwed in, when the crawler protrusion rides on the wheels or the tread of the idler, there is no escape (it can cause deformation or damage to the fuselage, push rod, and sometimes the crawler itself). It was.

(d) Means for Solving the Problems The present invention aims to solve the above-mentioned problems by providing a hydraulic cylinder connected to the idler, and further connecting the hydraulic chamber of the hydraulic cylinder to the hydraulic chamber. It is characterized in that it communicates with a hydraulic cylinder for lifting and lowering the working part via a check valve that prevents water from flowing out.

(E) Effect Based on the above-mentioned configuration, the pressure oil that raises and lowers the working part acts on the hydraulic chamber of the hydraulic cylinder for lifting and lowering the working part, and also acts on the hydraulic chamber of the hydraulic cylinder for pushing the idler via the check valve. , the idler is pressed against the crawler by the pressure acting on the hydraulic chamber to automatically apply a predetermined tension to the crawler.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG.
A reaping section 5 is supported in front of the reaping section 5 so as to be movable up and down by a hydraulic cylinder. In addition, the crawler traveling device 2 has drive wheels 6
, a large number of roller wheels 7..., an idler 9, and a crawler 10 wound around these, and the idler 9
An automatic crawler tensioning device 11 according to the present invention is installed in the vehicle.

As shown in FIG. 1, the automatic crawler tensioning device 11 has a hydraulic cylinder 12 for pushing an idler, and a piston 12a of the cylinder 12 is connected to a support shaft 9a of the idler 9. Moreover, the hydraulic chamber 12b of the hydraulic cylinder 12
is in communication with a hydraulic chamber 15a of a hydraulic cylinder 15 for raising and lowering the reaping section 5 via an oil passage a and a check valve 13, and the hydraulic chamber 15a of the hydraulic cylinder 15 is connected to a hydraulic chamber 15a which is operated by a hydraulic lever 16. It communicates with valve 17. Further, the switching valve 17 communicates with a hydraulic pump 19 and a tank 20, and a relief valve 21 is connected to the pressure oil path from the hydraulic pump 19.
are arranged in a branched manner.

Further, the oil path a between the idler pushing hydraulic cylinder 12 and the check valve 13 is branched and communicated with a pressure accumulator 22, and also communicates with a pressure relief valve 23. is in communication with the tank 20. Note that the check valve 13 does not prevent the flow from the reaping section lifting hydraulic cylinder 15 toward the idler pushing hydraulic cylinder 12, but blocks the flow in the opposite direction. Further, 10a is a projection formed at the center of the back surface of the crawler, and the idler 9 and the like are engaged and guided in the groove formed by these projections 10a.

Since this embodiment has the above configuration, the switching valve 1
7 is operated to supply pressure oil from the hydraulic pump 19 to the hydraulic cylinder 15 for raising and lowering the reaping section, the reaping section 5 rises and the pressure oil from the pump 19 passes through the check valve 13 and the oil passage and pushes the idler. The piston 12a expands and moves the idler 9 in the tensioning direction.

Then, the reaping section 5 is fully raised and the hydraulic cylinder 15
When the hydraulic pump 19 extends to the stroke end, the pressure oil from the hydraulic pump 19 is relieved by the relief valve 21, and the relief pressure consisting of the predetermined high pressure is applied to the idler pushing hydraulic cylinder 1.
2 and is also supplied to the pressure accumulator 22. As a result, relatively high pressure oil having a constant pressure of i is constantly introduced into the hydraulic chamber 12b of the hydraulic cylinder 12.
When the idler 9 presses the crawler 10 with a constant pressure, a force is exerted on the crawler 10, and a constant tension is always applied to the crawler 10.

Furthermore, even if the crawler 10 extends and the piston 12a extends together with the idler 9, oil is sent from the pressure accumulator 22 to the hydraulic chamber 12b to guarantee the pressure in the hydraulic chamber 12b. As the reaping section 5 moves up and down, relief pressure frequently acts on the idler pushing hydraulic cylinder 12, and oil corresponding to the new extension position is supplied to the hydraulic chamber 12b.
A constant pressing force always acts on the idler 9. Note that when operating the switching valve 17 to drain the lifting hydraulic cylinder 15 into the tank 20 and lowering the reaping section 5, the check valve 13 prevents the pressure oil from flowing out of the idler pushing hydraulic cylinder 12. Therefore, the hydraulic chamber 12b
Even when the pressure of
The pressure a is applied to the idler pushing hydraulic cylinder 12 via the check valve 13. Further, when an abnormal load is applied to the crawler 10, the pressure in the hydraulic chamber 12b of the idler pushing hydraulic cylinder escapes to the pressure accumulator 22, and the idler 9 is retracted, thereby absorbing the abnormal load on the crawler 10. When replacing the crawler 10, the pressure relief valve 23 is opened to drain the oil in the hydraulic chamber 12b of the hydraulic cylinder and the pressure accumulator 22 into the tank 20, and the pressing force of the idler 9 is removed. It will be done.

Next, a partially modified embodiment will be described based on FIG. 2.

In the above embodiment, the pressure relief valve 23 is installed for idler replacement, etc.
Even if the pressure in the hydraulic chamber 12b is released by operating the idler 9, the idler 9 will only return to the extended length of the crawler 10, so it is necessary to push the idler 9 back by hand or the like until the piston 12a is in the forged state.

Also, if you use rubber crawlers for many years,
The rubber, core metal, and steel cord will deteriorate, but if you always apply a constant strong tension to prevent the crawler from coming off,
This will accelerate deterioration and shorten the lifespan.

Therefore, in this embodiment, a spring 25 is compressed between the back surface of the piston 12b and the cylinder end surface 12c, so that the spring 25 acts against the pressure in the hydraulic chamber 12b, and the pressure is applied to the hydraulic chamber 12b. When the piston 12a is not acting, the piston 12a is configured to move to a forged state.

Therefore, when the crawler 10 deteriorates and expands significantly, the piston 12a is moved between the springs 2 and 3 by the hydraulic chamber 12b to which a constant pressure based on the relief pressure is applied.
Stretch against 5. At this time, the spring 25 is deformed to a greater extent, and a large biasing force is stored, and this biasing force goes against the pressure in the hydraulic chamber 12b, which is a constant pressure, and
The pressing of the idler 9 by the idler 9 acts in the direction of reducing the force. As a result, the pressing force of the idler 9 is reduced according to the amount of elongation of the crawler 10, and an optimum tension is applied to cope with crawler deterioration, thereby maintaining a long life of the crawler 10.

Furthermore, when the pressure release valve 23 is opened and the oil in the hydraulic chamber 12b of the hydraulic cylinder and the pressure accumulator 22 is drained into the tank 20, the piston 12a is moved to the forged state by the spring 25, and the idler 9 is also integrated. Move to crawler 1
0, making it easy to replace the crawler.

(g) As described in detail, according to the present invention, the pressure oil for raising and lowering the working parts such as the reaping part 5 is supplied to the hydraulic cylinder 15 for raising and lowering the working parts.
In addition to acting on the hydraulic chamber 15a of the hydraulic cylinder 12 for pushing the idler via the check valve 13, the pressure acting on the hydraulic chamber 12b automatically causes the idler 9 to maintain a predetermined tension. can be applied to the crawler 10, no idler tensioning work is required, equal and optimal tension can be applied to the left and right crawlers 10, 10, and unevenness in crawler tension can be eliminated. Furthermore,
Even if the crawler 10 extends, oil corresponding to the extension is automatically supplied to the hydraulic chamber 12b of the idler pushing hydraulic cylinder 12, so a predetermined crawler tension can always be applied regardless of the amount of crawler extension. Even without adjusting the tension, it is possible to prevent the crawler from coming off and being unable to run. In addition, if the pressure accumulator 22 is installed branching off to the oil path a between the idler pushing hydraulic cylinder 12 and the check valve 13, even if the crawler protrusion 10a rides on the wheel 7 or the idler tread when the crawler comes off, Abnormal loads caused by running aground can be absorbed by the pressure accumulator 22, thereby preventing deformation or damage to the aircraft body or crawler.

[Brief explanation of drawings]

Fig. 1 is an overall schematic diagram showing an automatic crawler tensioning device according to the present invention, Fig. 2 is an overall schematic diagram showing a partially modified embodiment thereof, and Fig. 3 is an overall side view showing a combine harvester to which the invention is applied. It is. 1. Work vehicle M (combine harvester), 2. Crawler traveling device, 3. Machine body, 5. Working part (reaping part)
, 9 Idler , 10... Crawler ,
11. Automatic crawler tensioning device, 12. Hydraulic cylinder for pushing idler, 12a. Piston,
12b71II pressure chamber, 13... check valve, 15
Hydraulic cylinder for lifting and lowering the working part, 15a Hydraulic chamber
, 21. Relief valve, 22... Pressure accumulator, 2
3.Pressure relief valve

Claims (1)

[Claims] (1) In the work vehicle 1 in which the working part 5 is supported by the hydraulic cylinder 15 on the machine body 3 supported by the crawler traveling device 2 so as to be able to rise and lower, the hydraulic cylinder 12 is connected to the idler 9 of the crawler traveling device 2. The automatic crawler tensioning device is configured such that the hydraulic chamber 12b of the hydraulic cylinder is communicated with the hydraulic cylinder 15 for lifting and lowering the working part via a check valve 13 that prevents outflow from the hydraulic chamber.