JPH11124067A - Idler supporting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the assembly of an idler to a truck frame easier, and to allow effective restriction of movement of the idler during running. SOLUTION: An axial portion of a yolk 40 is connected to a connecting member 41 that is connected and fixed to an end of a piston 22 that protrudes from a cylinder 19 that constitutes an adjuster 18. For an end face of the connecting member 41, a projection 41b is formed in the center of peripheral connecting plane 41a, and for an end face of the axial portion of the yolk 40, a connecting plane 42a is formed in a circular shape. In the center of the connecting plane 42a, a fitting concave portion 42b is formed to fit the projection 41b of the connecting material 41. The yolk 40 and the connecting member 41 arranged in the piston 22 fit each other in a concave and convex form so that relative movements other than those in the axial direction are restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for an idler constituting a lower traveling body in a hydraulic shovel and other construction machines.

[0002]

2. Description of the Related Art An example of a construction machine is a hydraulic shovel as shown in FIG. In FIG. 1, reference numeral 1 denotes a lower traveling body, and an upper revolving body 3 is installed on the lower traveling body 1 via a revolving device 2 so as to be capable of turning. Upper revolving superstructure 3
Is provided with a driver's cab 4 and a front working mechanism 5 including a boom 5a, an arm 5b, and a bucket 5c. The front working mechanism 5 is used to perform operations such as excavation of earth and sand. Has become.

The lower traveling body 1 is provided with track frames 11 on both left and right sides of a traveling body frame (not shown), and one end side of each of the track frames 11 (usually a rear side in the traveling direction).
A sprocket 12, which is driven to rotate by a hydraulic motor (not shown), is mounted on the vehicle, and an idler 13 is provided on the other end (front side in the running direction). A crawler belt 14 is provided between the sprocket 12 and the idler 13. It is provided by winding. Thus, the left and right traveling units are formed by the sprockets 12, idlers 13 and crawler belts 14 provided on the left and right track frames 11, and the respective sprockets 12
Are driven independently by a hydraulic motor to drive the vehicle.

[0004] The idler 13 is rotatably supported by the track frame 11, and the idler 13 causes the crawler belt 1 to rotate.
The system is provided with a mechanism for adjusting the tension of 4 and exerting a shock-absorbing effect when the vehicle collides with an obstacle during traveling. 6 to 8 show a support structure of the idler 13. FIG.
As is apparent from these figures, the shaft 15 of the idler 13
Are rotatably supported by a pair of left and right bearings 17 provided in connection with the yoke 16.

[0005] As is apparent from FIG.
The shaft portion 16b is connected to a support portion 16a having a substantially U-shape, and a bearing 17 is connected and fixed to the tip of the support portion 16a. The track frame 11 is provided with guide portions 11a and 11b, which are formed by bending a steel plate up and down in a substantially L-shape, and fixedly provided by means such as welding. Guide part 11
a and 11b are arranged at predetermined intervals above and below, and a space extending in a horizontal direction and extending to a predetermined length is formed therebetween. The bearing 17 connected to the support 16a of the yoke 16 is sandwiched between the guides 11a and 11b, and is movable in the horizontal direction. A bearing 17 is provided on a support 16 a of the yoke 16, and the shaft 15 of the idler 13 is mounted on the bearing 17. Idler 1
Since the crawler belt 14 is wound around the yoke 16, the movement of the yoke 16 in the direction protruding from the track frame 11 is regulated by the crawler belt 14 being wound around the idler 13. On the other hand, for the opposite direction of the yoke 16,
The crawler belt 14 is regulated by an adjuster 18 that performs a tension adjusting function.

FIG. 9 shows a schematic configuration of the adjuster 18.
The adjuster 18 includes a cylinder 19 and a buffer spring 20. The spring 20 is elastically mounted between a spring receiver 21 fixedly provided on the track frame 11 and a flange portion 19a of a cylinder 19, and a piston 22 is slidably inserted into the cylinder 19. Cylinder 1
9 and the piston 22 inserted therein, the working chamber 23
The working chamber 23 is filled with, for example, grease as a high-viscosity fluid. Therefore, if the amount of the high-viscosity fluid filled in the working chamber 23 is increased or decreased, the piston 22 extends or contracts with respect to the cylinder 19, so that the yoke 16 is connected to the guide portions 11a and 11a.
The tension of the crawler belt 14 can be adjusted by sliding the idler 13 in a direction of pressing against the crawler belt 14 or displacing the idler 13 in a direction away from the crawler belt 14 by sliding along the 11b. Further, the connecting rod 24 is provided with a greasing portion 27 for supplying grease into the cylinder 19, and the connecting rod 24 is provided with a passage extending from the greasing portion 27 to the working chamber 23. .

When the tension of the crawler belt 14 is adjusted, the yoke 16 has its shaft portion 16b in contact with the piston 22, and this piston 22 is connected to the cylinder 19. Therefore, the crawler belt 14 has tension. The reaction force generated by the action acts on the cylinder 19. Therefore, the tip of a connecting rod 24 is connected to the cylinder 19, the connecting rod 24 is fitted to a spacer 25, and the other end is fixed to a spring receiver 21 with a nut 26. Spring receiver 21
Is fixed to the track frame 11 so that the track 1
4 is received by the track frame 11 via the cylinder 19, the connecting rod 24 and the spring receiver 21.

The high viscosity fluid in the cylinder 19 is sealed, and the cylinder 19 is urged by the spring 20 in the direction of contact with the yoke 16.
The adjuster 6 and the adjuster 18 function as a unit in the front-rear direction. The spring 20 is provided to exert a shock-absorbing effect when the vehicle collides with an obstacle during traveling. When the vehicle travels, the idler 13 is normally positioned in the forward direction in the traveling direction. Thus, when the vehicle travels on the ground having unevenness and poor traveling conditions, the riding comfort is improved by the buffering action of the spring 20.

[0009]

The yoke 16
The adjuster 18 and the adjuster 18 are not fixed, and the shaft 16 b of the yoke 16 is kept in contact with the end face of the piston 22 protruding from the cylinder 19. In this state,
As long as no external force acts, the yoke 16, the piston 22, the cylinder 19,
Further, the connecting rod 24 and the spring receiver 21 are all held in a state of being aligned with the center axis A (FIG. 9) in the front-rear direction of the vehicle.

When the vehicle is running, external forces in various directions act on the idler 13. Since the idler 13 is elastically pressed and held in the front-rear direction by the urging force of the spring 20,
The external force acting in the direction parallel to the central axis A acts only in the direction of compressing the spring 20, that is, the force in the direction of arrow H in FIG. 9, so that a large load acts in this direction even if they are not fixed to each other. There is no danger that the contact portion will shift. However, at the joint between the shaft portion 16b of the yoke 16 and the piston 22, no restriction is imposed except for the direction of the central axis A, so that when an external force acts in any direction, the joint surfaces are displaced or mutually inclined. Movement occurs.

In particular, the running conditions of the hydraulic excavator are extremely severe because the excavator works on uneven terrain, rubble and the like, and the running condition of the excavator is extremely severe.
Since 4 has a wide width, it vibrates violently up and down and is largely inclined in the left-right direction. Therefore, an excessive external force acts in the direction in which the idler 13 is pushed up, tilted, or twisted, and the shaft 1
Forces in various directions act on the joint between the piston 6b and the piston 22. As a result, the idler 13, the shaft 15, the bearing 17,
There is a possibility that the yoke 16 and the guide portions 11a and 11b of the track frame 11 with which the yoke 16 abuts may be deformed or damaged. In severe cases, such deformation and damage may cause a problem that results in poor rotation of the idler 13.

Since the cylinder 19 is connected and fixed to the track frame 11 by the connecting rod 24, in order to suppress the above-described movement, as shown in FIG. 10, a bearing 30 on which the shaft 15 of the idler 13 is mounted is used. A configuration in which the connected and fixed yoke 31 is connected and fixed to the rod 33 inserted into the cylinder 32 is conceivable.

As is apparent from FIG. 1, a thread is provided at the tip of the rod 33 and a spacer 34 is attached. On the other hand, the yoke 31 has a concave portion 31a and a shaft insertion portion 35 through which the rod 33 is inserted. A stopper 33a is provided at one end of the rod 33. By disposing the stopper 33a in the cylinder 32, the space between the rod 33 and the cylinder 32 is fixedly held at a predetermined position. Further, the piston 36 inserted into the cylinder 32 is configured to be fixed to the track frame 11. And the spring 37 which exerts a buffering action
Is mounted between the end face of the yoke 31 and the flange 32 a provided on the cylinder 32.

With the above construction, the center axes of the yoke 31, the rod 33, the cylinder 32, and the piston 36 are maintained in a fixed state from the shaft 15 of the idler 13, and the external force is applied to the idler 13 from any direction. The movement of the idler 13 can be restricted even if the above-mentioned operation is performed.
Therefore, these parts can be prevented from being deformed or damaged.

When the cylinder 32 and the yoke 31 are thus connected and fixed via the rod 33, the idler 13 can be stably held. However, it is necessary to assemble the idler 13 with the rod 33 and the cylinder 32 assembled in addition to the yoke 31. For this reason, there is a disadvantage that the weight of the entire assembly is increased and it becomes difficult to mount the idler 13 on the track frame 11.

The present invention has been made in view of the above points, and it is an object of the present invention to easily attach an idler to a track frame and to effectively restrict the movement of the idler during traveling. To be able to do it.

[0017]

In order to achieve the above-mentioned object, the present invention provides a track frame consisting of a pair of right and left wheels mounted with a traveling unit formed by winding a crawler belt between a sprocket and an idler. In order to adjust the tension of each crawler belt, an adjuster is configured by slidably mounting a yoke that supports the rotation shaft of the idler movably in the horizontal direction and a piston that pushes the yoke in a cylinder. Is mounted on the track frame, the yoke is provided with a shaft, and the shaft is brought into contact with the piston of the adjuster. The feature is that the fitting portion is formed.

Here, the concave / convex fitting portion may be configured such that a projection is provided on one side of a joint portion between the shaft portion of the yoke and the piston, and a concave portion is formed on the other side. Further, the piston may be formed with a portion which is directly in contact with the shaft portion of the yoke and is fitted with the concave and convex portions. Can also be formed.

[0019]

Embodiments of the present invention will be described below. First, FIGS. 1 and 2 show a first embodiment of the present invention, and FIGS. 3 and 4 show a second embodiment. In these embodiments, the overall schematic structure of the idler support structure is not particularly different from that shown in FIG. 9, and therefore, the same or equivalent components as those shown in FIG. The description is omitted by attaching the reference numerals.

1 and 2, reference numeral 40 denotes a yoke, and the yoke 40 includes a pair of left and right support portions 40a,
A bearing 17 on which the shaft 15 of the idler 13 is mounted is connected and fixed to the support portion 40a. Further, a shaft portion 40b is connected to both of the support portions 40a, 40a. On the other hand, the joining member 4 is attached to the tip of the piston 22 projecting from the cylinder 19 constituting the adjuster 18.
1 are connected and fixed by means such as press fitting. The end surface of the joining member 41 is provided with a projection 41 at the center of the surrounding joining surface 41a.
b is formed. The tip surface of the shaft portion 40b of the yoke 40 is a joining surface 42a formed in an annular shape.
A fitting recess 42b for fitting the projection 41b of the joining member 41 is formed at the center thereof. Therefore, the yoke 40
Is not directly joined to the piston 22, but is connected and fixed to the piston 22.
Is joined to the joining member 41 forming an integral body. The joining surface 42a of the shaft portion 40b is
The projection 41b of the joining member 41 is fitted into the fitting recess 42b at the center of the shaft portion 40b in a state of contact with the joining surface 41a. Here, the fitting between the fitting concave portion 42b and the projection 41b is loosely fitted so that a slight gap is generated, so that the fitting and the disengagement of the fitting can be easily performed. Moreover, both the fitting concave portion 42b and the protrusion 41b have a substantially frusto-conical shape, and by having such a tapered shape,
It will function as a call-in part when both are fitted.

The piston 22 is drawn into the cylinder 19 unless the cylinder 19 is filled with a high-viscosity fluid such as grease. 22
Can be separately assembled to the track frame 11. When grease or the like is supplied from the greasing unit 27 into the cylinder 19 after the assembly is completed, the piston 22 projects and the joining surface 41a of the joining member 41 at the tip thereof.
Abuts on the joint surface 42a of the shaft portion 40b of the yoke 40, and the fitting recess 42b on the shaft portion 40b side and the protrusion 41b of the joint member 41 are fitted into the concave and convex. Here, since a slight gap is formed in the fitting portion between the fitting concave portion 42b and the protrusion 41b and the calling portion is provided, the projection 41 of the joining member 41 is surely formed by the projection of the piston 22.
b fits into the fitting concave portion 42b of the shaft portion 40b, and the outer portions thereof come into surface contact with each other. by this,
The idler 13 and its supporting mechanism are
Attached to.

As described above, the shaft 1 provided on the idler 13
Piston 2 connecting yoke 40 and joining member 41 to 5
2 and the cylinder 19, the connecting rod 24 and the spring receiver 21 are all maintained in alignment with the center axis A in the front-rear direction of the vehicle. And in this state,
Everything except the space between the yoke 40 and the joining member 41 is fixedly connected. The yoke 40 and the joining member 41 are fitted with the fitting concave portion 42b and the projection 41b. Therefore, the direction in which the yoke 40 and the joining member 41 approach and separate from each other can freely move. However, cylinder 19
Is biased by the spring 20, and the tension of the crawler belt 14 is applied to the idler 13 to which the yoke 40 is connected. Therefore, the yoke 40 is constantly applied with a force in the direction of pressing against the joining member 41. Therefore, even if an external force acts in this direction, that is, the joining surface 42a on the shaft portion 40b of the yoke 40
Even if an external force acts in a direction away from the joining surface 41a of the joining member 41, the fitting state between the fitting recess 42b and the projection 41b is stably maintained. In addition to this direction, relative movement is restricted by the fitting of the fitting recess 42b and the projection 41b. As a result, even when forces on the idler 13 in various directions are applied to the idler 13 through the crawler belt 14 when the vehicle travels on rough roads and gets over unevenness on the ground, the idler 13 and the yoke 40 connected to the idler 13 are applied. Movement is effectively regulated. Therefore, idler 13, shaft 15,
There is no risk of deforming or damaging the bearing 17, the yoke 40, and the guide portions 11a and 11b of the track frame 11 with which the yoke 40 contacts.

Next, in the second embodiment shown in FIGS. 3 and 4, the left and right support portions 50a,
A joint surface 51a is provided around the shaft portion 50b which is connected to the shaft 50b.
Is formed, and a frustoconical projection 51b is formed at the center of the joining surface 51a. On the other hand, it is connected and fixed to the tip of the piston 22 by means such as press fitting,
The joining member 52 integrated with the piston 22 has a joining surface 52a at an outer peripheral portion and a fitting concave portion 52b at a central portion. With this configuration,
Since the yoke 50 is fitted to the piston 22 via the joining member 52, the yoke 50, the cylinder 19, and the piston 22 are separately assembled into the track frame 11 and then separated from each other, as in the first embodiment. In the connected state, the movement of the idler 13 can be regulated and stably held by the concave-convex fitting portion.

[0024]

As described above, according to the present invention, the shaft portion is provided on the yoke, the shaft portion is brought into contact with the piston of the adjuster, and the uneven fitting portion is provided therebetween. It is easy to assemble the idler to the track frame, and it is possible to effectively control the movement of the idler during traveling.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an idler support mechanism according to a first embodiment of the present invention, in which an adjuster is sectioned.

FIG. 2 is a side view of FIG. 1 showing a main part in cross section.

FIG. 3 is a plan view showing a configuration of an idler support mechanism according to a second embodiment of the present invention, in which an adjuster is sectioned.

FIG. 4 is a side view of FIG. 3 showing a main part in cross section.

FIG. 5 is an external view of a hydraulic shovel as an example of a construction machine.

FIG. 6 is a side view showing a conventional structure for supporting an idler on a track frame.

FIG. 7 is a sectional view taken along line XX of FIG. 6;

FIG. 8 is a plan view of a main part of a support mechanism of the idler.

FIG. 9 is a plan view showing a section of an adjuster of an idler support mechanism according to the related art.

FIG. 10 is a plan view showing an idler support mechanism according to another conventional technique in which a portion of an adjuster is sectioned.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower traveling body 10 Center frame 11 Track frame 11a Guide part 12 Sprocket 13 Idler 14 Crawler belt 18 Adjuster 19 Cylinder 20 Spring 21 Spring receiver 22 Rod 23 Working chamber 24 Connecting rod 40, 50 Yoke 40a, 50
a Supporting portions 40b, 50b Shaft portions 41, 52
Joining members 41a, 42a, 51a, 52a Joining surfaces 41b, 51b Projections 42b, 52
b Fitting recess

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiaki Sekiguchi 650 Kandamachi, Tsuchiura-shi, Ibaraki Prefecture Within Hitachi Construction Machinery Engineering Co., Ltd.

Claims (4)

[Claims] 1. A track frame comprising a pair of left and right sides,
A yoke that supports a rotating shaft of the idler so as to be movable in a horizontal direction, in order to mount a traveling unit formed by winding a crawler belt between a sprocket and an idler and adjust the tension of each crawler belt, An adjuster configured by slidably mounting a pushing piston in a cylinder is mounted on the track frame. A shaft is provided on the yoke, and the shaft is used as a piston of the adjuster. An idler support structure for a construction machine, wherein a contact portion between the shaft portion and the piston is formed with an uneven fitting portion. 2. A piston of the adjuster is provided with a flange portion and a projection protruding from the flange portion, and a fitting surface of the yoke which is in contact with a flange portion of the piston and the projection is loosely fitted on a shaft portion of the yoke. 2. The idler support structure for a construction machine according to claim 1, wherein a concave portion is provided to be fitted in a shape. 3. A joint surface having a projection in the center is provided on the shaft portion of the yoke, and a flange portion and the projection are loosely fitted on the piston of the adjuster. The idler support structure for a construction machine according to claim 1, wherein a concave portion to be fitted is provided. 4. A structure in which a joining member is connected to the distal end of the piston, and the joining member is brought into contact with the shaft portion of the yoke and is fitted into the projection and recess. An idler support structure for a construction machine according to any one of claims 2 and 3.