JPH0872761A - Adjusting device for crawler tension - Google Patents

Abstract

PURPOSE: To appropriately adjust the tension of a crawler according to the condition of a working site by using a hydraulic cylinder for the adjust mechanism of the crawler and actuating the hydraulic cylinder by operating a switching valve. CONSTITUTION: A cylinder 24 is disposed behind a yoke 9 for supporting a slide block 4. An adjuster mechanism 23 is constructed by interposing a buffer spring 10 between a spring seat 24A formed in front of this cylinder 24 and a spring receiver 9A formed in the rear face part of the yoke 9. The cylinder 24 is driven back and forth by supplying pressure oil supplied from a pressure oil source 26 to the head side chamber 24B or the rod side chamber 24C of the cylinder 24 via a switching valve 27, an idler 5 is moved back and forth via the spring 10, the yoke 9 and the slide block 4 and tension of a crawler 6 is adjusted. Further, the leakage of the pressure oil inside the head side chamber 24B is prevented by a pilot check valve 28 inserted into a tube passage 31 and slackening of the crawler 6 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension adjusting device for a crawler mounted mainly on construction machines such as hydraulic excavators and work vehicles.

[0002]

2. Description of the Related Art FIG. 4 is a side view of a main portion of a lower traveling body 1 showing a first embodiment of a crowbar tension adjusting device of the prior art. In the figure, reference numeral 2 denotes a side frame of the lower traveling body 1, and a guide portion 3 having an open tip is provided at one end of the side frame 2. Reference numeral 4 is a slide block slidably fitted in the guide portion 3, reference numeral 5 is an idler rotatably supported by the slide block 4, and reference numeral 6 is a crawler wound around the idler 5. Next, 7 shows an adjuster mechanism which constitutes a tension adjusting device of the crawler. Reference numeral 8 denotes a cylinder of the adjuster mechanism 7, which has a flange-shaped spring seat 8A on one side in the axial direction of the cylinder 8 and a rod portion 8B on the other side in the axial direction. Reference numeral 9 denotes a yoke which is continuously provided at the rear portion of the slide block 4, and the yoke 9 is provided.
A spring receiver 9A facing the spring seat 8A of the cylinder 8 is formed in the rear portion, and a spring 10 is stretched between the spring seat 9A and the spring seat 8A. Reference numeral 11 denotes a piston slidably fitted in the cylinder 8, and the end portion of the piston 11 is supported by the side frame 2. Further, a grease nipple 12 for enclosing the grease in the cylinder 8 is attached near the end of the piston 11. As described above, the conventional adjuster mechanism 7 includes the cylinder 8, the yoke 9, the spring 10, the piston 11, and the grease nipple 12. And green nipple 1
The cylinder 8 is slid to the idler 5 side by injecting grease into the cylinder 8 via the 2 and the idler 5 is displaced to the tip side of the side frame 2 via the yoke 9 so as to move the black. -The tension of the la 6 is adjusted. On the other hand, while the hydraulic excavator is running, the crawlers may collide with obstacles such as rocks and receive a large impact load. When the idler 5 comes into the state, the idler 5 is retracted through the yoke 9 against the spring force of the spring 10, so that the black
The la 6 can maintain an appropriate tension.

FIG. 5 shows a second embodiment of the prior art.
It is a principal part side view of the tension | tensile_strength adjustment apparatus of the crawler described in the 2-114882 publication. As shown in the figure, an opening 14 is formed in the upper surface of the side frame 13 at the center in the longitudinal direction. 15 is an adjuster mechanism 1 described later.
In order to support 6, the side frame 13 is a support portion vertically protruding from the lower surface of the upper portion of the side frame 13 so as to face the opening 14, and is formed in a cylindrical shape with a bottom. 16 is the support portion 15
The adjuster mechanism provided in FIG. Reference numeral 17 is a cylinder of the adjuster mechanism, and the cylinder 17 is a spring seat 17
A and a small diameter oil passage 17B are integrally formed. 18
Is a support portion 1 facing the spring seat 17A of the cylinder 17
5 is a spring receiver provided on the inner bottom portion, and a spring 19 for elastically supporting the cylinder 17 in the vertical direction is stretched between the spring receiver 18 and the spring seat 17A of the cylinder 17. Two
Reference numeral 0 denotes a piston slidably fitted in the cylinder 17, and the piston rod 20A of the piston 20 has an opening 1
4 protrudes toward the upper crawler 6. A yoke 21 is fixed to the upper end of the piston rod 20A, and an upper roller 22 for guiding the crawler 6 is rotatably attached to the yoke 21. As described above, the adjuster mechanism 16 includes the cylinder 17, the spring receiver 18, the spring 19 and the piston 20,
Grease is injected into the cylinder 17 through the grease nipple 12 and the oil passage pipe 17B, and the piston 20 is raised to raise the upper roller 22 so that the crawler 6 can maintain an appropriate tension. Adjust the height to. On the other hand, when the crawler 6 receives a large tension due to collision with an obstacle while the hydraulic excavator is running, the upper roller 22 is pushed down by the crawler 6, and the yoke 21 and the piston rod are pushed. The piston 20 descends via 20A so as to compress the grease. As a result, the cylinder 17 has the spring 1
It slides down in the support portion 15 against the spring force of 9 and the
The tension applied to the roller 6 at the time of collision can be released, and the appropriate tension is always applied to the roller 6.

[0004]

The above-mentioned prior art crowbar tension adjusting device has the following problems. When running the hydraulic excavator on sandy ground,
The sand may be caught in the crawler, and the crawler may be strongly stretched, resulting in excessive tension, which may cause partial wear of the crawler parts, particularly the track link pins, and power loss. For this reason, when traveling on normal sandy land, the operator must
It is necessary for the machine to remove grease from the cylinder and loosen the tension of the crawlers before running. However, the work is to loosen the screw with a tool, to handle the removed grease,
Since it takes a lot of time to clean it, it seems that most of the adjustment work of the crawler is not performed at present. The present invention aims to solve the above problems.

[0005]

In order to achieve the above object, a tension adjusting device for a crawler according to the present invention has a cylinder arranged behind a yoke supporting a slide block, and a front portion of the cylinder. A spring seat perpendicular to the axis of the cylinder is formed, a spring receiver is formed on the rear surface of the yoke so as to face the spring seat, and a buffer spring is stretched between the spring seat and the spring receiver. The end portion of the piston rod protruding from the rear of the cylinder is supported by the side frame, while the pressure oil supplied from the hydraulic pressure source is supplied to the head side chamber or the rod side chamber of the cylinder through the switching valve. By doing so, the cylinder is actuated to move the idler in the forward and backward directions to adjust the tension of the crawler.

A flange having a spring seat is arranged behind the yoke supporting the slide block, and a spring receiver is formed on the rear surface of the yoke so as to face the spring seat of the flange. A cushioning spring is stretched between the seat and the spring receiver to support the flange on the side frame, while an opening is formed at the center of the upper surface of the side frame in the longitudinal direction. -Insert the cylinder vertically toward the inside of the frame to support it on the side frame, fix the yoke on the upper end of the piston rod protruding from the opening, and attach the crawler to the yoke. A guide upper roller is rotatably mounted, and pressure oil supplied from an oil pressure source is supplied to the head side chamber or the rod side chamber of the cylinder through a switching valve to operate the cylinder to operate the upper roller. On La, it is moved downward, the black - and to adjust the tension of the La.

A pilot switching valve is inserted in the middle of the pipeline connecting the hydraulic power source and the cylinder, and a pilot valve is provided in the operator's cab to connect the pilot valve and the pilot switching valve by a pipeline. By operating the pilot valve, the cylinder is operated via the pilot switching valve, and the tension of the crawler is adjusted from the cab.

[0008]

When working with a hydraulic excavator, for example, when the machine is run on sandy ground, the sand is caught in the crawlers and the crawlers are tensioned strongly, resulting in an over tension condition. Parts, especially track link pins, may wear and power loss may occur. For this reason, when traveling on a normal sandy ground, it is necessary for the operator to relax the tension of the chlora in advance before traveling. In this way, the tension of the chlora is usually adjusted according to the situation at the site.
In the crawler tension adjusting device of the present invention, a hydraulic cylinder is used for an adjuster mechanism arranged at the rear part of the slide block supporting the idler, and the idler is moved forward and backward while operating the hydraulic cylinder by operating a switching valve. It is moved in the direction to adjust the tension of the crawlers. Alternatively, an opening is formed in the center of the upper surface of the side frame in the longitudinal direction, a hydraulic cylinder is erected inside the side frame of the opening, and a yoke is provided at the upper end of the piston rod of the cylinder projecting from the opening. An upper roller is attached to guide the crawler via. Therefore, it is possible to adjust the tension of the crawler by operating the switching valve to operate the piston rod to move the upper roller upward and downward. Since the tension of the crawler can be adjusted simply by operating the switching valve in this way, the tension of the crower can be easily obtained according to the situation of the site without getting the hands dirty. Further, a pilot switching valve is used to operate the hydraulic cylinder, and a pilot valve is provided in the operator's cab so that the pilot switching valve can be operated by the pilot valve. As a result, the tension of the crawler can be adjusted easily by simply operating the pilot valve in the operator's cab, which is more convenient.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a crawl tension adjusting device according to claim 1 of the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. An idler 5 rotatably supported by a slide block 4 is disposed on one end side of the side frame 2. Reference numeral 23 denotes an adjuster mechanism that constitutes the tension adjusting device of the crowbar 6,
Reference numeral 4 is a cylinder of the adjuster mechanism 23, and a spring seat 24A is formed on the front surface of the cylinder 24. Reference numeral 9 denotes a yoke that is continuously provided at the rear portion of the slide block 4, and a spring receiver 9A is formed on the rear surface of the yoke 9 so as to face the spring seat 24A of the cylinder 24. The spring 10 is stretched between 24A. Reference numeral 25 is a piston rod of the cylinder 24, and an end portion of the piston rod 25 is supported by the side frame 2. Further, the hydraulic pressure source 26 and the switching valve 27 are connected by a conduit 30, and the head side chamber 24B and the rod side chamber 24C of the cylinder 24 and the switching valve 27 are connected by conduits 31 and 32, respectively. In addition, a pilot check valve 28 is inserted in the middle of the pipeline 31 and branched from the pipeline 30 to release the relief valve 2.
9 is provided. As described above, the adjuster mechanism 23 is composed of the cylinder 24, the yoke 9, and the spring 10.
The pressure oil supplied from the hydraulic pressure source 26 is passed through the switching valve 27 to the head side chamber 24B or the rod side chamber 24C of the cylinder.
The cylinder 24 is actuated in the front-rear direction by supplying the water to the idler 5, and the idler 5 is moved forward and backward through the spring 10, the yoke 9 and the slide block 4 to adjust the tension of the crawler 6. it can. The pilot check valve 28 inserted in the pipe line 31 prevents the pressure oil from leaking in the head side chamber 24B of the cylinder 24 and prevents the crawler 6 from loosening. Further, the relief valve 29 regulates the maximum pressure of the pressure oil and can prevent the crawler 6 from being overtightened. On the other hand, when the crawler 6 collides with an obstacle such as rock and receives a large tension while the hydraulic excavator is running, the idler 5 retreats through the yoke 9 against the spring force of the spring 10. The crawler 6 can maintain an appropriate tension.

FIG. 2 is an explanatory view of a crowbar tension adjusting device according to claim 2 of the present invention. An idler 5 rotatably supported by the slide block 4 is disposed on one end side of the side frame 13. Reference numeral 33 denotes a shock absorber, and 34 is a flange of the shock absorber 33, and a spring seat 34A is formed on the front surface thereof. Reference numeral 9 denotes a yoke which is continuously provided on the rear portion of the slide block 4, and the spring seat 34 is provided on the rear surface portion of the yoke 9.
A spring receiver 9A facing A is formed, and a spring 10 is stretched between the spring receiver 9A and the spring seat 34A. The flange 34 is supported by the side frame 13. An opening 35 is formed on the upper surface of the side frame 13 at the center in the longitudinal direction. 36 is the opening 3
5 is a supporting portion provided on the side frame 13 facing the side 5. A cylinder 37 is erected on the support portion 36, and a piston rod 38 of the cylinder 37 projects toward the crawler 6. A yoke 39 is fixed to the upper end of the piston rod 38, and an upper roller 22 for guiding the crawler 6 is rotatably attached to the yoke 39. Further, the hydraulic pressure source 26 and the switching valve 27 are connected by the pipe line 26, and the head side chamber 37A of the cylinder 37 is connected.
And the rod-side chamber 37B and the switching valve 27 through the conduit 4 respectively.
1, 42 are connected. Further, a pilot check valve 28 is inserted in the middle of the pipeline 41, and a relief valve 29 is provided branching from the pipeline 40. Therefore, the hydraulic power source 26
By supplying the pressure oil supplied from the cylinder to the head side chamber 37A or the rod side chamber 37B of the cylinder via the switching valve 27, the piston rod 38 is actuated in the vertical direction, and the upper roller 22 is moved via the yoke 39. The tension of the crawler 6 is adjusted by moving it upward and downward. Further, the pilot check valve 28 prevents the pressure oil from leaking in the head side chamber 37A of the cylinder 37 and prevents the crawler 6 from loosening. Further, the relief valve 29 regulates the maximum pressure of the pressure oil to prevent the crawler 6 from being overtightened.
On the other hand, when the crawler 6 collides with an obstacle such as rock and receives a large tension while the hydraulic excavator is running, the idler 5 retreats through the yoke 9 against the spring force of the spring 10. The crawler 6 can maintain an appropriate tension.

FIG. 3 is a hydraulic system diagram of a crowbar tension adjusting device according to a third aspect of the present invention. In the figure, reference numeral 43 denotes a pilot switching valve inserted between the hydraulic power source 26 and the cylinder 24 for adjusting the tension of the crawler 6, and the hydraulic power source 26 and the pilot switching valve 43 are connected by a pipe line 47 to form a cylinder. 24
The head side chamber 24B, the rod side chamber 24C, and the pilot switching valve 43 are connected to each other by pipelines 48 and 49, respectively. Further, a pilot valve 45 is provided in the operator's cab 46, the pilot valve 45 is connected to a pilot hydraulic power source 44 via a pipe line 50, and the output portion of the pilot valve and the operating portion of the pilot switching valve 43 are piloted. Conduit 5
1, 52 are connected. Therefore, by operating the pilot valve 45, the pilot pressure oil supplied from the hydraulic pressure source 44 is sent to the operating portion of the pilot switching valve 43,
The pilot switching valve 43 is operated to supply the pressure oil from the hydraulic pressure source 26 to the head side chamber 24B or the rod side chamber 24C of the cylinder 24, and the cylinder 24 is expanded and contracted to cause the crow 6 to move.
The tension can be adjusted. In this way, the cab 46
By operating the pilot valve 45 inside, the tension adjustment of the crawler 6 can be easily performed.

[0012]

According to the present invention, since the hydraulic cylinder is used for the adjusting mechanism of the crawler and the hydraulic cylinder is operated by the operation of the switching valve, it is possible to easily adjust the tension of the crawler. became. This makes it possible to easily obtain the proper tension of the crawler according to the situation of the work site,
Since it is possible to avoid excessive tension of the crawler, uneven wear of the track pin can be prevented and power loss can be prevented. In addition, a pilot valve is installed in the driver's cab so that the tension of the crawler can be adjusted from the driver's cab, which makes it even more convenient. As a result, the adjustment work can be significantly shortened, and the maintenance cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a crawler tension adjusting device according to claim 1 of the present invention.

FIG. 2 is an explanatory diagram of a crowbar tension adjusting device according to claim 2 of the present invention.

FIG. 3 is a hydraulic system diagram of a crawler tension adjusting device according to claim 3 of the present invention.

FIG. 4 is a side view of the essential portions of the lower traveling body showing the first embodiment of the chlora tension adjusting device of the prior art.

FIG. 5 is a side view of a main part of a lower traveling body showing a second embodiment of the chlora tension adjusting device of the prior art.

[Explanation of symbols]

 4 Slide Block 5 Idler 6 Crawler 7, 16, 23 Adjuster Mechanism 8, 17, 24, 37 Cylinder 9, 21, 39 Yoke 10, 19 Spring 11, 20A, 25, 38 Piston Rod 22 Upper Roller 27 Switching valve 43 Pilot switching valve 45 Pilot valve

Claims (3)

[Claims] 1. An idler is attached to one end of each of left and right side frames constituting a lower traveling body via a slide block which is movable in the front-rear direction, and a crawler is hung around the idler to tension the crawler. In a crawler-type construction machine provided with an adjuster mechanism for adjusting and buffering, a cylinder is arranged behind a yoke supporting the slide block, and a spring perpendicular to the axis of the cylinder is provided on the front surface of the cylinder. A seat is formed, a spring receiver is formed on the rear surface of the yoke so as to face the spring seat, a buffer spring is stretched between the spring seat and the spring receiver, and the rear of the cylinder is provided. The end of the more projecting piston rod is supported by the side frame, while the pressure oil supplied from the hydraulic pressure source is supplied to the head side chamber or rod side chamber of the cylinder through the switching valve. A tension adjusting device for a crawler, wherein the idler is moved to move the idler forward and backward to adjust the tension of the crawler. 2. An idler is attached to one end of each of the left and right side frames constituting the lower traveling body via a slide block which is movable in the front-rear direction, and the idler is rotated around the idler to tension the idler. In a crawler-type construction machine provided with an adjuster mechanism for adjusting and buffering, a flange having a spring seat is disposed behind a yoke supporting the slide block, and the rear surface of the yoke is provided with the flange. A spring bearing is formed facing the spring seat of the flange, and a cushioning spring is stretched between the spring seat and the spring bearing to support the flange on the side frame, while the side frame is supported.
An opening is formed at the center of the upper surface of the frame in the longitudinal direction, and the cylinder is vertically inserted from the opening toward the inside of the side frame so that the cylinder is supported by the side frame, and at the upper end of the piston rod protruding from the opening. Fix the yoke, and
The upper roller for guiding the crawler is rotatably attached to the cylinder, and pressure oil supplied from a hydraulic pressure source is supplied to the head side chamber or the rod side chamber of the cylinder through a switching valve to thereby move the cylinder. A tension adjusting device for a crawler which is activated to move the upper roller upward and downward to adjust the tension of the crawler. 3. A pilot switching valve is inserted in the middle of a pipeline connecting the hydraulic pressure source and the cylinder, and a pilot valve is provided in the operator's cab to connect the pilot valve and the pilot switching valve by a pipeline. Claims 1 and 2 are characterized in that the cylinder is operated via the pilot switching valve by operating the pilot valve, and the tension of the crawler is adjusted from the operator's cab. The tension adjusting device for the crower described in 2.