JP2003327174A - Travelling drive unit of track-laying-type vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a travelling drive unit of a track-laying-type vehicle with increased durability in a sprocket and the bush of a crawler and improved easiness of replacement of an abrasion member and the driving force transmission function of the sprocket. <P>SOLUTION: In the travelling drive unit of the track-laying-type vehicle, gear thickness is set slightly smaller than the circular arc length between bushes 5, 5 of the crawler 3 meshing with a gear section 21 in the sprocket 20, and a groove 22 force earth movement is provided in a centripetal direction on the side of the gear section 21. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling drive device for a construction machine, such as a bulldozer or a hydraulic excavator, which is a track-type construction machine vehicle that mainly works on rough terrain. The present invention relates to a traveling drive device for a tracked vehicle having a function of enhancing the durability of a driven sprocket.

[0002]

2. Description of the Related Art Conventionally, a traveling device in a track-type construction machine vehicle has an endless track formed on a sprocket and an idler incorporated in a drive device provided at a required distance in front of and behind the vehicle body. It is designed to be wrapped around and run. The crawler track has a number of track links (hereinafter simply referred to as links) arranged on the left and right at predetermined intervals.
A bush provided between them and a plurality of connecting pins that are inserted into each bush to connect the links to each other, and a shoe plate is bolted onto each of the left and right links to form an endless shape. ing.

As shown in FIG. 5, the traveling device having the crawler belt having such a structure is driven by the sprocket 101 assembled to the drive wheel 100 of the drive device and the bush 108 of the crawler belt 105 sequentially meshing with each other during traveling. When engaging, the bush 108 provided on the connecting pin 107 that connects the link 106 of the crawler belt 105 and the tooth 102 of the sprocket 101 mesh with each other to transmit power. However, when the crawler belt 105 that is driven by meshing with the sprocket 101 moves to the ground contact surface side, the track plate comes into contact with the ground to support the vehicle body, so that the crawler belt 105 is wound around the sprocket 101 (ground contact surface side). The push-up force acts through the bush 108 of the crawler belt 105 which meshes with the teeth of the sprocket.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the tooth portion 102 of the sprocket 101, not only the surface pressure with the bush 108 due to the rotational driving force but also the thrust load generated for supporting the vehicle body, the initial position where the bush 108 meshes sequentially, and the slippage when the tooth portion 102 is separated from each other. The load caused by is large. Furthermore, the earth and sand to be hoisted during traveling on an uneven terrain is affected by the teeth 102 of the sprocket 101 and the crawler belt 1.
No. 05 enters the meshing part with the bush 108, and when the running operation is continued, the friction with the sand is remarkable, and the bush 10
8 and the tooth portion 102 of the sprocket are severely worn. In particular, in a track-type vehicle such as a bulldozer that repeatedly moves violently for a long period of time, the sprocket 101 is worn out so much that it must be replaced frequently. Therefore, the replacement of the sprocket requires not only the cost of the replacement part but also a lot of labor for the replacement, and the work vehicle cannot be used during that time, which causes a problem such as a delay in construction period.

Further, as shown in FIG. 5, the tooth portion 102 of the sprocket 101 of such a traveling drive device has a general sprocket tooth shape, and therefore meshes with the bush 108 of the crawler belt 105. In this state, the tooth portion 10 of the sprocket 101 is
When the bush 108 of the crawler belt 105 and the bush 108 of the crawler belt 105 are intruded into the inside of the link 106, when the bush 108 and the tooth portion 102 are engaged with each other, they are rubbed against each other by the earth and sand to cause a large amount. Friction will occur. Moreover,
In the conventional sprocket tooth part, the backlash at the meshing part between the tooth surface and the bush is large, so if driving operation that frequently moves forward and backward continues, the sand that enters the meshing part causes friction. Since the tooth wear is severe due to the severe vibration, the power transmission function may be deteriorated, and the replacement frequency increases, so that the durability is required to be increased.

The present invention has been made in view of the above circumstances, and provides a tracked vehicle in which the durability of the sprocket is improved, the wear members are easily replaced, and the driving force transmission function of the sprocket is improved. It is an object of the present invention to provide a traveling drive device.

[0007]

In order to achieve the above-mentioned object, a traveling drive device for a track-tracked vehicle according to the present invention comprises:
The tooth thickness of the sprocket is slightly smaller than the arc length between the bushes of the crawler belt with which the tooth portions of the sprocket are meshed, and the side surface of the tooth portion is provided with a groove for earth removal in the centripetal direction. Is.

According to the present invention, the tooth thickness of the tooth portion of the sprocket of the power transmission mechanism in the traveling drive device of the crawler belt is compared with the meshing space portion between the bushes in the link of the crawler belt driven by being wound around. Since the meshing is large within the allowable range, the earth and sand that enter and move into the links of the crawler belt during driving act so as to be pushed out when meshing with the teeth of the sprocket. The earth and sand pushed toward the non-grounded surface side is discharged in the axial direction through the groove provided on the tooth side surface without being compacted between the tooth tip and the track surface. Therefore, it is possible to prevent the sand and sand from being caught in the meshing surfaces of the bushes and the tooth portions, resulting in severe wear of both, and it is possible to reduce the frequency of replacing the sprockets and improve the operation efficiency. In addition, the tooth strength is increased by increasing the tooth thickness, and since the gap between the bush and the tooth surface is small during the forward / backward reversing operation during traveling, so-called play can be reduced and instant reversal driving can be performed. Therefore, there is an effect that mobility can be enhanced as a traveling drive device for a working machine that frequently repeats forward and backward movements.

It is preferable that the soil discharging groove provided on the side surface of the tooth portion of the sprocket is formed so as to widen from the tooth root toward the mounting portion side (second invention). This way
When the teeth of the sprocket and the crawler belt link are engaged, when the sand that enters the link and is brought into the link is discharged by the pressing force applied to the non-ground surface side of the crawler belt by the tooth tip, resistance to the discharge side By reducing the amount, it is possible to obtain the effect that the soil is promptly discharged and the frictional resistance at the meshing portion due to the earth and sand can be reduced.

The sprocket is preferably composed of a plurality of segments divided at an intermediate position where the bushes and teeth of the crawler belt do not mesh with each other, and is detachably attached to the drive wheel (third invention). . Further, it is preferable that the sprocket segment includes an attachment portion that can be detachably bolted from the outside to a flange-shaped attachment portion formed on the drive wheel (fourth invention). This has the effect that the assembly or replacement work becomes easy, sometimes the segments can be partially replaced, and the manufacturing cost can be reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, specific embodiments of a traveling drive device for a track-mounted vehicle according to the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a drive unit of a traveling drive device for a track-mounted vehicle according to the present invention. FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is an enlarged plan view taken along the line BB of FIG.

The traveling drive device 1 of this embodiment comprises an idler (not shown) and a crawler belt 3 wound around a drive wheel 2 on both sides of a vehicle body frame as a lower traveling body in a track-type vehicle (not shown). The crawler belt 3 is attached to a vehicle body frame and is driven by a drive wheel 2 via a reduction gear mechanism 6 by receiving power transmitted from an engine (not shown). In this configuration, the relationship between the sprocket 20 that transmits power to the link 4 of the crawler belt 3 in the drive wheel 2 and the link 4 of the crawler belt will be described.

The drive wheel 2 includes a planetary gear speed reduction mechanism 6 supported by an end portion of a vehicle body frame of a well-known structure, a wheel 8 fixedly supported by an output shaft 7 of the planetary gear reduction mechanism 6, and an outer periphery of the wheel 8. It is composed of a ring-shaped sprocket 20 which is concentrically mounted on a mounting portion 8a formed in a brim.

The wheel 8 is supported by the boss portion 6b of the casing 6a of the planetary gear reduction mechanism 6 via a rolling bearing 6c, and the planetary gear reduction mechanism 6 is projected through the boss portion 6b to the outside. The output shaft 7 (integrated with the carrier) is coaxially connected via a support ring 9 fitted and fixed by a spline key at the end. And
A large number of sprocket mounting holes 11 are provided at a predetermined radial position in the collar-shaped mounting portion 8a so as to be parallel to the axis at a predetermined pitch.

The sprocket 20 is an intermittent tooth having a plurality of teeth. As shown in FIG. 1, the link 4 is provided between the tooth portions 21 and 21 (corresponding to the roots of teeth). The tooth thickness is increased by alternately forming a portion where one bush 5 is connected and a portion where two bushes 5 are connected. The tooth portion 21 that meshes with the bush 5 is a portion that receives two of the bushes 5 and a portion that receives one of the tooth portions 21 and one bush 5. Therefore, FIG.
As shown in FIG. 5, a gap s is formed between the bush 5 that does not contact the tooth portion 21 and the tooth surface so that a gap s that does not interfere with driving is formed.

The tooth portion 21 of the sprocket 20 has a tooth thickness dimension T which is substantially smaller than the arc length obtained by subtracting the diameter of the bush 5 from one pitch of the pins that connect the links 4 of the crawler belt 3 to each other. The tip 21a is formed flat. In addition, a groove 22 for earth removal having an appropriate width is formed on both side surfaces at the center of the side surface of the tooth portion 21. The groove 2
2 is from the tooth root toward the center of the wheel 8 (centering direction)
The shape is widened to facilitate the discharge of sediment.

As shown in FIG. 1, the sprocket 20 of the present embodiment thus configured is formed into an intermittent tooth shape with every two teeth and is divided at an intermediate position in the intermittent portion 23 of the teeth. It is configured by combining four segments. Therefore, each sprocket segment 20a
Have the same shape. The inner peripheral portion of each sprocket segment 20a is formed into a stepped shape, and the rear side step portion of the collar-shaped mounting portion 25 of the inner peripheral portion of the collar-shaped mounting portion 8a of the wheel 8 is formed. The collar-shaped mounting portion 8a of the wheel 8 is engaged with the outer periphery.
Mounting hole 11 provided on the engaging surface of
And a mounting hole of the mounting portion 25 provided at a pitch that matches the sprocket mounting hole 11, a nut 27 is screwed into a fastening bolt 26 inserted from the rear surface, and is fastened and fixed.

The traveling drive system 1 of the present embodiment thus constructed receives the power from the drive source and the planetary gear mechanism 6 is received.
The speed is reduced to a required speed, the sprocket 20 rotates together with the wheel 8, and the crawler belt 3 wound around the sprocket 20 is driven to travel. When the link 4 of the crawler belt 3 moves and the bush 5 of the connecting portion thereof is driven by meshing with the tooth portion 21 of the sprocket 20, each tooth portion 21 other than the intermittent tooth portion 24 of the sprocket is rotated. The bush 5 meshes with the surface. Therefore, the sprocket 20
For the meshing of the link with the link 4 (bush 5), see 8
As a result, four teeth will actually mesh with one tooth,
Power is transmitted at a position where the teeth 21 come into contact with and mesh with each other. However, since each tooth portion 21 can be made large in tooth thickness dimension unlike a tooth of a general sprocket, power can be reliably transmitted. The bush 5 located at a position that does not mesh with the tooth portion 21 has a tooth forming space portion (intermittent portion 24).
Although the drive force is not directly received at, the link 4 is connected and moved.

Thus, when the link 4 of the crawler belt 3 meshes with the tooth portion 21 of the sprocket 20, for example, the link 4 of the crawler belt 3 may mesh with the non-grounded surface side of the crawler belt 3, particularly in the space inside the link 4 in a state where earth and sand enter and adhere. Even if there is, the tooth portion 21 of the sprocket 20
Has a large tooth thickness T and has a small gap at the time of meshing with the bushes 5 and 5 located in the front and rear in the rotation direction, the earth and sand in the space inside the link 4 is discharged to both side surfaces of the tooth 21. Since the groove 22 for use is provided, it is pushed back toward the shoe plate 3a side by the tooth tip 21a and is extruded to the outside along the groove 22 for earth removal. Since the groove 22 has a shape that spreads from the root of the tooth toward the center of the wheel 8, when the earth and sand in the internal space of the link receives a pressing force, it is easily extruded and the earth is compacted inside the groove 22. There is no such thing. Therefore, it is possible to reduce the amount of earth and sand caught between the bush 5 and the tooth bottom portion 23, and the bush 5 and the tooth surface being rubbed by the earth and sand.

Further, since the tooth portion 21 of the sprocket 20 is formed with the tooth thickness T larger than usual, the strength can be increased and the radial load and the traction load can be shared and driven without any trouble. Therefore, there is an advantage that it is not necessary to increase the diameter of the bush 5b or use an expensive material, and it is possible to reduce the manufacturing cost on the track side. Of course, the wear resistance of the sprocket 20 is improved, and the frequency of replacement can be reduced.

When the tooth portion 21 of the sprocket 20 wears out due to long-term use and it becomes necessary to replace it, the segment 20a of the divided sprocket is unfastened from the wheel 8 by the mounting bolts 26 and nuts 27. It can be easily removed. In the fastening portion formed by the bolts 26 and the nuts 27, the nuts 27 are loosened on the front surface so that the sprocket segment 20a can be detached and the sprocket segment 20a can be removed. It has good performance and can be easily replaced on site.

FIG. 4 is an enlarged front view of the essential parts of another embodiment of the sprocket. In this embodiment, the basic configuration is the same as that of the previous embodiment, but the structure of the sprocket is partly different. Therefore, the same structural parts as those of the above-mentioned embodiment are designated by the same reference numerals as those described above, and the description thereof will be omitted.

In this embodiment, the sprocket 20A has an intermittent portion formed every other tooth, and the sprocket segment 20 divided at the intermediate position of each intermittent portion.
It is configured by combining a plurality of b (for example, eight).
Each of these sprocket segments 20b is a flange-shaped mounting portion 25 formed on the inner peripheral portion, and the step portion behind the sprocket segment 20b is formed on the outer periphery of the wheel 8 in the same manner as in the above embodiment. The wheel 8 is engaged with the mounting portion 8a.
It is fastened and fixed by a bolt 26 and a nut 27 through a mounting hole provided so as to match the sprocket mounting hole 11 provided on the side.

The sprocket 20A of such an embodiment
In the above, since it is substantially the same as the sprocket 20 of the above-described embodiment, the same operational effect as that of the above-described embodiment is obtained. The sprocket 20A of this embodiment is
Then, since the sprocket segment 20b for each tooth is combined, even if a situation occurs in which a part of the sprocket segment 20b is damaged, there is an advantage that it can be dealt with by replacing only that part. Also, its sprocket segment 2
Since all of 0b are divided and formed with the tooth portion 21 as a reference, they can be produced under the same conditions in production, and there is also an advantage that handling in machining becomes easy.

As described above, according to the present invention, in a sprocket configured to be replaced when worn due to operation, the portion worn by the influence of earth and sand when being engaged with the link (bush) of the crawler belt is reinforced. In addition, since the construction is such that the soil discharging function is added, it is possible to obtain a traveling drive device capable of enduring long-term use and prolonging the replacement period.

[Brief description of drawings]

FIG. 1 is a side view of a drive unit of a travel drive device for a track-type vehicle according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged plan view taken along line BB of FIG.

FIG. 4 is an enlarged front view of essential parts showing another embodiment of the sprocket.

FIG. 5 is a diagram showing a drive unit of an example of a travel drive device in a conventional tracked vehicle.

[Explanation of symbols]

1 traveling drive 2 drive wheels 3 tracks 3a Footwear 4 Track links 5 bush 6 Planetary gear mechanism 8 wheels 8a mounting part 11 Sprocket mounting hole 20,20A sprocket 20a, 20b sprocket segment 21 Sprocket teeth 21a addendum 22 Ditch for earth removal 23 Tooth bottom 25 Sprocket mounting part 26 bolts

Claims (4)

[Claims] 1. In a traveling drive device for a tracked vehicle, a tooth thickness of a sprocket is set to be slightly smaller than an arc length between bushes of a crawler belt which meshes with each other, and a side surface of the tooth portion is ejected in a centripetal direction. A travel drive device for a tracked vehicle, which is provided with a groove for soil. 2. The traveling drive device for a track-tracked vehicle according to claim 1, wherein the soil discharging groove provided on the side surface of the tooth portion of the sprocket is formed so as to expand from the tooth root toward the mounting portion side. . 3. The sprocket is composed of a plurality of segments divided at an intermediate position where a bush of a crawler belt and a tooth portion do not mesh with each other, and is detachably attached to a drive wheel. A traveling drive device for a track-tracked vehicle according to item 1. 4. The tracked vehicle according to claim 3, wherein the sprocket segment includes an attachment portion that can be detachably bolted from the outside to a flange-shaped attachment portion formed on the drive wheel. Travel drive.