JP2006160073A - Variable leg structure of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable leg structure of a working vehicle capable of smoothly moving right and left inner pipes with respect to an outer pipe without generating any set-in of the outer pipe even during the maximum leg opening, and smoothly changing the spacing between crawlers. <P>SOLUTION: The variable leg structure of the working vehicle comprises an outer pipe 7o which is provided along the width direction of a center frame 7 and has a sliding part 2b having an inside diameter face of the diameter smaller than that of an inside diameter face 7o1 at a center part on an end thereof, and inner pipes 8r, 9r, 8l, 9l which are fixed to track shoes 4l, 4r, and reciprocated in the outer pipe 7o while sliding on the inside diameter face of the sliding part sb to move the track shoes 4l, 4r in the width direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a variable leg structure in which a crawler belt extends and contracts in a width direction in a work vehicle such as a hydraulic excavator.

    Conventionally, a work vehicle such as a hydraulic excavator is used by transporting the work vehicle on a truck bed or when the work vehicle passes through a narrow place by using the left and right crawler belts contracted in the width direction. When performing, there is a variable leg structure in which the left and right crawler belts are extended in the width direction.

  This variable leg structure is formed by a central outer pipe and left and right inner pipes that slide in the width direction in the outer pipe. The outer pipe is attached to a center frame that supports a working vehicle body, and the left and right inner pipes are The left and right track shoes around which the crawler belts are wound are respectively fixed.

  The outer diameter of the outer pipe and the inner diameter of the inner pipe are set with a predetermined gap for sliding.

In addition, there exist the following patent documents 1 and 2 as literature well-known invention concerning this application.
Japanese Utility Model Publication No. 6-13040 Utility Model Notice Sho 63-24071

    By the way, in the above-described variable leg structure, since the outer pipe is attached to the center frame which takes a large weight of the vehicle body, when the left and right track shoes around which the crawler belt is wound are moved outward in the width direction, the heavy weight is applied. The central outer pipe sinks downward with respect to the inner pipe fixed to the left and right track shoes, and the parallelism between the central outer pipe and the left and right inner pipes is lost.

  For this reason, the edge of the inner pipe in the outer pipe squeezes the inner surface of the outer pipe, and the sliding movement of the left and right inner pipes with respect to the outer pipe cannot be performed smoothly. May not be possible.

  Note that Patent Document 1 has the above-mentioned problems, and Patent Document 2 has a complicated configuration.

  In view of the above situation, the present invention provides a variable work vehicle that can smoothly move the left and right inner pipes with respect to the outer pipes and smoothly change the interval between the crawler belts without causing the outer pipes to sag even when the legs are fully opened. The purpose is to provide a leg structure.

    In order to achieve the above object, a variable leg structure for a work vehicle according to claim 1 of the present invention comprises a lower traveling body having a track shoe around which a crawler belt for traveling is wound on both sides and a center frame on a central portion. A variable leg structure for a work vehicle that moves both the track shoes in the width direction to change the distance between the crawler belts on both sides, and is provided along the width direction of the center frame and is thinner than the inner diameter surface of the center portion An outer pipe having a sliding part with an inner diameter surface at the end and an outer pipe fixed to the track shoe, and reciprocatingly moved in the outer pipe by sliding on the inner diameter surface of the sliding part. And an inner pipe that moves in the direction.

  A variable leg structure for a work vehicle according to a second aspect of the present invention is the variable leg structure for a work vehicle according to the first aspect, wherein the variable leg structure of the work vehicle is close to an outer end edge portion of the sliding portion and between the outer pipe and the inner pipe. A cylindrical dust seal sandwiched between the two is provided.

  A variable leg structure for a work vehicle according to claim 3 of the present invention is the variable leg structure for a work vehicle according to claim 1 or 2, wherein a fluid for injecting lubricant into the inner diameter surface of the sliding portion is provided. A ting is provided on the outer pipe.

    As described above in detail, according to the variable leg structure of the work vehicle according to claim 1 of the present invention, the slide is provided along the width direction of the center frame and has an inner diameter surface narrower than the inner diameter surface of the center portion. An outer pipe having a moving portion at an end thereof, and an inner pipe fixed to the track shoe and reciprocating in the outer pipe by sliding on the inner diameter surface of the sliding portion to move the track shoe in the width direction. Therefore, the parallelism of the inner pipe with respect to the outer pipe is maintained, the inner pipe can reciprocate without contacting the inner surface of the outer pipe, and the track shoe can move smoothly in the width direction.

  Further, even when both the track shoes are opened to the maximum, the outer pipe provided in the center frame, which is heavy in weight, is prevented from falling downward.

  According to the variable leg structure of the work vehicle according to the second aspect of the present invention, since the cylindrical dust seal sandwiched between the outer pipe and the inner pipe is provided near the outer edge of the sliding portion, dust or the like Intrusion into the outer pipe is prevented.

  According to the variable leg structure of the work vehicle according to claim 3 of the present invention, since the fitting for injecting the lubricant into the inner diameter surface of the sliding portion is provided in the outer pipe, lubrication is periodically performed through the fitting. By injecting the agent, sliding between the inner pipe and the sliding portion can be performed smoothly.

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

  As shown in FIG. 1, a hydraulic excavator (work vehicle) 1 according to an embodiment of the present invention is attached to a lower traveling body 2 in which a crawler belt r for movement is installed, and to an upper portion of the lower traveling body 2 so as to be freely rotatable. And an upper swing body 3 on which a person gets on and performs work.

  The upper revolving unit 3 is provided with an operation seat 3a on which an operator sits and performs an operation, and in front thereof, is attached to the hydraulically driven boom 10a, the arm 10b, and the tip of the arm 10b. The working machine 10 having the excavating bucket 10c is pivotally supported so as to be swingable in the vertical direction.

  At the lower part of the upper revolving unit 3, a revo frame R as a base and a counterweight w fixed to the rear part of the revo frame R in order to balance the front and rear weights with respect to the front work machine 10 are disposed. ing.

  Further, in the lower exterior panel 3p1 of the upper swing body 3, a swing motor, a hydraulic valve main valve, a multi-controller, a fuel tank, and a hydraulic circuit for swinging the upper swing body 3 with respect to the lower traveling body 2 are provided. The hydraulic oil tank which comprises is arrange | positioned. Further, in the exterior panel 3p, an engine which is a pump drive source in the hydraulic circuit is disposed in a central portion in front of the counterweight, and the radiator for radiating the engine, a cooling fan for cooling the pump, and the pump are provided. An oil cooler connected by hydraulic piping, a battery, and the like are disposed.

  The lower traveling body 2 has driving wheels 5 and idle wheels 6 mounted on both ends of a pair of left and right track shoes 4l and 4r, respectively, and a crawler belt r is wound between the driving wheels 5 and the idle wheels 6. Disguise.

  In addition, a blade bracket br (see FIG. 2) is provided at the front portion of the lower traveling body 2 so that the blade b used when the soil dug back by the bucket 10c is backfilled can perform a predetermined operation as a soil discharge plate. ) To be freely swingable.

  The hydraulic excavator 1 having the above-described configuration rotates by driving the engine to convert the energy into hydraulic pressure and transmitting the power to the drive wheels 5, and by rotating the drive wheels 5, the crawler belt r is rotationally driven to travel. And various operations using the bucket 10c and the blade b are performed.

  Here, the distance between the track shoes 4l and 4r disposed on the left and right sides of the vehicle body is determined by the configuration described later, with the hydraulic cylinders (not shown) as the drive source and the track shoes 4l and 4r in the vehicle body width direction (see FIG. It can be expanded and contracted by moving each of them in a direction perpendicular to the paper surface of 1. For example, when the excavator 1 itself is transported by a truck for transportation, or when the excavator 1 passes through a narrow place, the distance between the outer edges of the crawler belts r on both sides is 980 mm at the shortest. Can shrink. On the other hand, during normal work, the distance between the outer edge portions of the crawler belts r and r can be extended to 1273 mm as much as possible.

  As shown in FIG. 2, the frame 2 </ b> F of the lower traveling body 2 is provided with a center frame 7 in which a mounting ring 7 r to which the upper swing body 3 is attached is disposed in the center, and in front of the center frame 7, The blade bracket br to which the blade b and the hydraulic cylinder for operating the blade b are attached is welded.

  On the other hand, track shoes 4r and 4l are arranged on both sides of the center frame 7, and the track shoes 4r are connected to the center frame 7 by two inner pipes 8r and 9r fixed by bolts via a mounting bracket tb. ing. Similarly, the track shoe 4l is connected to the center frame 7 by two inner pipes 8l and 9l fixed by bolts via a mounting bracket tb.

  The track shoe 4r and the pair of inner pipes 8r and 9r, and the track shoe 4l and the pair of inner pipes 8l and 9l are configured symmetrically with respect to the center plane in the width direction of the center frame 7.

  That is, the inner pipe 8r and the inner pipe 8l are configured to have a symmetrical shape with respect to the center plane in the width direction of the center frame 7, and similarly, the inner pipe 9r and the inner pipe 9l It has a symmetrical shape with respect to the center plane in the width direction.

  FIG. 3 is a cross-sectional view taken along line AA of FIG. 2. The right side of the center line shows the state where the inner pipe 9l has moved most outward from the outer pipe 7o, and the left side of the center line shows that the inner pipe 9r is the outer pipe 7o. The most moved state is shown. The inner pipe 9l and the inner pipe 9r have the same configuration, and the inner pipe 9l is inserted into an outer pipe 7o provided in the center frame 7 and moves as indicated by an arrow α.

  Further, the front inner pipe 8l shown in FIG. 2 is also configured in the same manner as the inner pipe 9l, and reciprocates through an outer pipe (not shown) provided in the center frame 7. In this way, the track shoe 4l around which the crawler belt r is wound is expanded and contracted with respect to the center frame 7 as indicated by an arrow β in FIG.

  Here, the outer pipe 7o is provided across the width direction of the center frame 7 as shown in FIG. 2, and the inner diameter s1 of the outer pipe 7o at the center is outside the inner pipe 9l as shown in FIG. It is configured to be larger than the diameter s2. For example, the inner diameter s1 of the outer pipe 7o = 114 mm, and the outer diameter s2 of the inner pipe 9l = 111.2 mm.

  A cylindrical sliding member (sliding portion) sb constituting a sliding surface with the outer diameter surface 9l1 of the inner pipe 9l is fixed to the inner diameter surface 7o1 at the end of the outer pipe 7o by welding.

  The sliding member sb is manufactured using a normal steel material such as carbon steel, and has an inner diameter having an outer diameter s2 of the inner pipe 9l and a gap of 0.4 mm on one side, for example.

  In this way, the gap between the inner pipe 9l and the sliding member sb corresponding to the sliding portion between the inner pipe 9l and the sliding member sb is set narrow, and the outer pipe 7o of the outer pipe 7o is larger than the outer diameter s2 of the inner pipe 9l. Since the inner diameter s1 is set sufficiently large, the parallelism of the inner pipe 9l with respect to the outer pipe 7o is sufficiently maintained, and the inner pipe 9l slides on the inner diameter surface of the sliding member sb without contacting the inner diameter surface 7o1 of the outer pipe 7o. it can.

  Thus, since the inner pipe 9l does not contact the inner diameter surface 7o1 of the outer pipe 7o, the inner pipe 9l does not squeeze or wear the inner diameter surface 7o1 of the outer pipe 7o. The inner pipe 9l may contact the inner diameter surface 7o1 of the outer pipe 7o, but it is preferable that the inner pipe 9l does not contact like the present embodiment from the viewpoint of avoiding wear and the like.

  As the sliding member sb, a sintered metal used for a sliding bearing material or the like other than the carbon steel, an impregnation bush having a self-lubricating property by impregnating carbon can be used. In this case, the inner diameter of the sliding member sb can be configured to have an outer diameter s2 of the inner pipe 9l and, for example, a gap of 0.1 mm. Thus, it goes without saying that a material other than carbon steel can be used for the sliding member sb.

  Further, a grease injection fitting gf for injecting grease as a lubricant to the sliding surface of the sliding member sb is provided at the outer end portion of the outer pipe 7o to which the sliding member sb is fixed. . By periodically injecting the grease of the lubricant using the fitting gf, the lubrication between the inner diameter surface of the sliding member sb and the outer diameter surface 9l1 of the inner pipe 9l becomes good, and the sliding becomes smooth.

  In this embodiment, the outer pipe 7o is manufactured by casting such as lost wax and the sliding member sb as another member is fixed. However, the sliding member sb portion is cast as a part of the entire outer pipe 7o. May be manufactured. Alternatively, the outer pipe 7o may be manufactured from sheet metal and the separate sliding member sb may be fixed.

  Further, in order to prevent intrusion of dust, dirt, water, etc. into the outer pipe 7o, the cylindrical dust seal ds shown in FIG. 4 is brought close to the outer edge of the sliding member sb shown in FIG. The outer pipe 7o is disposed at a portion (B portion in FIG. 3) sandwiched between the inner diameter surface of the outer pipe 7o and the outer diameter surface 9l1 of the inner pipe 9l.

  This dust seal ds is formed by attaching a ring-shaped rubber ds2 inside a ring-shaped iron metal frame ds1, and prevents dust from external O from entering the outer pipe 7o by the metal frame ds1 and rubber ds2. Is done.

  Although the configuration around the inner pipe 9l and the outer pipe 7o has been described above, the configuration of the inner pipes 8l, 8r, 9r and the outer pipe shown in FIG. 2 is the same as the configuration around the inner pipe 9l and the outer pipe 7o described above. Detailed description will be omitted.

  As described above, the inner pipes 8l, 9l, 8r, and 9r are reciprocated inside the outer pipes by sliding the inner diameter surface of the sliding member sb, so that the distance between the track shoes 4l and 4r is changed in the width direction. The width between the crawler belts r on both sides of the excavator 1 can be freely expanded and contracted from the shortest 980 mm to the maximum width 1273 mm.

  According to the above configuration, the sliding member sb is arranged at the outer end of the outer pipe 7o, and the outer diameter surface of each inner pipe slides with the inner diameter surface of the sliding member sb with a narrow gap. The parallelism with respect to the outer pipe 7o can be kept at a predetermined value.

  For this reason, the inner pipes are prevented from twisting or coming into contact with the inner diameter surface of the outer pipe 7o, and even when the crawler belts r, r on both left and right sides are contracted and extended in the width direction, the sliding between the inner pipe and the outer pipe is prevented. Can move smoothly.

  Further, even when the crawler belts r on both sides are opened to the maximum extent, the outer pipe does not fall downward.

  Further, the dust seal is disposed between the inner surface of the outer end portion of the outer pipe 7o and the outer surfaces of the inner pipes 8l, 9l, 8r, 9r in the vicinity of the outer end edge portion of the sliding member sb. Intrusion of dust, dust, water, etc. can be reliably prevented.

  Further, since the fitting gf is formed at the outer end portion of the outer pipe 7o in which the sliding member sb is inserted, grease is periodically injected into the inner diameter surface of the sliding member sb through the fitting gf. Thus, the sliding between the inner diameter surface of the sliding member sb and the outer diameter surface 9l1 of the inner pipe 9l is smoothly lubricated. Therefore, a favorable sliding bearing operation can be performed, and the inner pipes 8l, 9l, 8r, 9r can be smoothly moved with respect to the outer pipe 7o.

As an application example of the present invention, a hydraulic excavator has been exemplified as a work vehicle, but it goes without saying that the present invention can be effectively applied to other work vehicles other than a hydraulic excavator having a similar configuration.

  For example, the present invention can be effectively used for crawler dumpers, bulldozers, agricultural machines, and the like in addition to hydraulic excavators.

The side view which shows the hydraulic excavator in connection with the Example of this invention. The perspective view which shows the frame of the lower traveling body in connection with the Example of this invention. In the center frame of the lower traveling body in FIG. 2, the right side is a case where the track shoe is fully extended, and the left side is a cross-sectional view taken along line AA when the track shoe is fully contracted. The side sectional view showing the dust seal concerning the example of the present invention.

Explanation of symbols

1 ... hydraulic excavator (work vehicle),
2 ... Lower traveling body,
4l, 4r ... track shoes,
7 ... Center frame,
7o ... outer pipe,
7o1 ... Inner diameter surface of outer pipe,
8r, 9r, 8l, 9l ... inner pipe,
ds ... dust seal,
gf ... fitting,
r ... tracks,
sb: sliding member (sliding portion).

Claims (3)

A lower traveling body (2) having a track shoe (4l, 4r) around which a crawler belt (r) for traveling is wound is provided on both sides and a center frame (7) in the center. 4r) is a variable leg structure of the work vehicle (1) for changing the distance between the crawler belts (r, r) on both sides by moving in the width direction,
An outer pipe (7o) provided along the width direction of the center frame (7) and having a sliding part (sb) having an inner diameter surface that is narrower than the inner diameter surface (7o1) at the center, at the end;
The track shoe (4l, 4r) is fixed to the inner surface of the sliding part (sb) and reciprocates in the outer pipe (7o) to move the track shoe (4l, 4r) in the width direction. Inner pipes (8r, 9r, 8l, 9l) to be moved to
A variable leg structure for a work vehicle. A cylindrical dust seal (ds) sandwiched between the outer pipe (7o) and the inner pipe (8r, 9r, 8l, 9l) close to the outer edge of the sliding part (sb); The variable leg structure for a work vehicle according to claim 1. The work vehicle according to claim 1 or 2, wherein a fitting (gf) for injecting a lubricant into an inner diameter surface of the sliding portion (sb) is provided in the outer pipe (7o). Variable leg structure.

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