JP4046544B2 - Traveling drive device for tracked vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traveling drive device for a construction machine vehicle, such as a bulldozer or a hydraulic excavator, which mainly works on rough terrain, and more specifically relates to the durability of a sprocket for driving a crawler track. The present invention relates to a traveling drive device for a tracked vehicle having a function to enhance.
[0002]
[Prior art]
Conventionally, a traveling device in a track-type construction machine vehicle travels with a crawler belt formed in an endless shape wrapped around a sprocket and an idler incorporated in a driving device provided at a predetermined distance before and after the vehicle body. Have been to. The crawler belt includes a plurality of track links arranged on the left and right sides at a predetermined interval, a bush provided therebetween, and a plurality of connection pins inserted into the bushes to connect the track links to each other. A crawler plate is bolted on the left and right track links to form an endless shape.
[0003]
A traveling device having a crawler belt having such a configuration is driven by the sprocket and the crawler bush being sequentially engaged during driving, and the crawler belt is in contact with the bottom of the sprocket while the mesh is engaged. Has been communicated. However, when the crawler belt driven by meshing with the sprocket moves to the ground plane side, the crawler plate is in contact with the ground and supports the vehicle body, so it is wound around the sprocket (the sprocket on the ground plane side). The push-up force acts through the bush of the shoeboard (which meshes with the teeth).
[0004]
For this reason, the sprocket teeth include not only the surface pressure against the bush due to the rotational driving force, but also the thrust load generated for supporting the vehicle body, the initial position where the bush sequentially engages, and the slip when separating from the tooth The load caused by In addition, the earth and sand that is rolled up when traveling on rough terrain enters the meshing area between the sprocket teeth and the bush of the crawler belt, and if the running operation continues, friction with the earth and sand becomes significant, and the teeth of the bush and sprocket teeth are severely worn. Become. In particular, in a tracked vehicle such as a bulldozer that repeatedly and violently moves over a long period of time, the sprockets are heavily consumed and often have to be replaced.
[0005]
Under these circumstances, in order to reduce the wear on the teeth of the sprocket of the travel drive device, as one way to improve the meshing structure of the crawler bush and the sprocket teeth, it is possible to drive without engaging the bush to the bottom of the tooth. There is a way of thinking. In this way, when the sprocket and the crawler bush are engaged, there is a gap in the root of the tooth even if soil enters, so when the bush engages with the tooth, friction is caused by rubbing with the sand that adheres to the bottom of the tooth. Can be prevented, and friction can be prevented from occurring due to earth and sand, thereby reducing wear. By the way, there is a prior art disclosed in Japanese Patent Laid-Open No. 10-45056, which has a different purpose from the present invention.
[0006]
As shown in FIG. 6, in the traveling apparatus for a tracked vehicle disclosed in Japanese Patent Laid-Open No. 10-45056, the sprocket 60 is fastened to the outer periphery of the housing 65 of the speed reducer by a bolt 66, and the crawler belt 70. Is wound around the sprocket 60 so that the inner surface 71a of the track link 71 of the crawler belt 70 abuts the outer peripheral surface (contact portion) of the housing 65 so that the sprocket 60 and the bush 72 of the crawler belt 70 are in contact with each other. In the meshing part, a configuration is disclosed in which a gap t is formed between the bush 72 and the tooth bottom 62. Reference numeral 61 denotes sprocket teeth.
[0007]
In addition, as another prior art example, there is one in which the configuration of the meshing portion between the sprocket and the crawler belt is changed to facilitate the replacement of the worn portion, for example, the one described in US Pat. No. 6,220,378. is there. FIG. 7 is a side view showing a part of the structure in section. In this prior art, a plurality of meshing members 82 are detachably attached at an equal pitch to the outer peripheral portion of a hub 81 attached to a speed reducer to constitute a sprocket assembly 80. On the other hand, traction lugs 77 are detachably attached to the non-ground surfaces of the crawler plate 76 of the crawler belt 75 by bolts 78, respectively. The mesh member 82 of the sprocket assembly 80 and the groove 79 provided by the front and rear end portions of the traction lug 77 of the crawler belt 75 mesh with each other to drive the crawler belt 75 and receive a radial load. Yes. In short, the meshing member 82 and the groove 79 of the traction lug 77 receive the driving force and the radial load at the same time. Therefore, since the meshing member 82 and the traction lug 77 are wear members, they can be detached and exchanged easily.
[0008]
[Problems to be solved by the invention]
However, the prior art described above has the following problems.
First, in the one disclosed in Japanese Patent Laid-Open No. 10-45056, when the crawler belt 70 is wound around the sprocket 60, the link contact portion in the outer peripheral portion of the housing 65 of the speed reducer and the inner peripheral side of the track link 71 are disclosed. Since the surface 71a is in contact with the outer surface 71a, the link contact portion on the outer peripheral portion of the housing 65 is worn. If such wear occurs, the reduction gear housing 65 needs to be replaced, which requires a lot of time for replacement, and the cost of replacement parts is high. Further, since the surface 71a on the inner periphery side of the crawler belt of the track link 71 is also heavily worn, the life of the link is reduced. In general, the track link and crawler belt replacement work is very difficult and the replacement cost is high, so the actual situation is that the track link and crawler belt replacement frequency is set lower than the sprocket replacement frequency. If the frequency of track link replacement increases for the reason, it will be a large economic loss.
[0009]
Further, in the one disclosed in the above-mentioned U.S. Pat. No. 6,220,378, the driving force and the radial load of the engagement member 82 of the sprocket assembly 80 and the traction lug 77 on the crawler belt 75 side are simultaneously received. Becomes shorter and the replacement frequency increases. Therefore, since it is necessary to replace the high-cost engaging member 82 and the traction lug 77, there is a problem that the maintenance cost naturally increases. In particular, in the meshing structure between the groove 79 provided in the traction lug 77 and the meshing member 82 of the sprocket assembly 80, the traction lug 77 is interposed between the meshing members 82 and 82 on the sprocket side. In a state where the earth and sand are involved, the earth and sand that have entered between the meshing members 82 and 82 are pressed by the bottom surface of the pulling lug 77, making it difficult to discharge to the outside. There is a problem that not only the rotation of the large member is prevented, the wear thereof becomes more intense, the smooth drive is not performed, and the replacement frequency is further increased.
[0010]
The present invention has been made in view of such a situation, and has improved the durability of the sprocket and the crawler belt bush, and has improved the ease of replacement of the wear member and the drive force transmission function of the sprocket. It is an object of the present invention to provide a travel drive device for a vehicle.
[0011]
[Means for solving the problems and actions / effects]
In order to achieve the above-described object, a traveling drive device for a tracked vehicle according to the first invention comprises:
In a traveling drive device for a tracked vehicle,
The sprocket has a tooth thickness slightly smaller than the length of the arc between the bushes of the crawler belt with which the tooth portion meshes, the tooth tip is formed on a flat surface, and a groove is provided in the centripetal direction on the side surface of the tooth portion, An abutting member is provided on the non-grounding surface side of the crawler belt so as to contact the tooth tip of the tooth portion and secure a gap between the bush and the tooth bottom portion of the sprocket.
[0012]
In the present invention, the sprocket of the power transmission mechanism in the crawler travel drive device and the crawler belt link that is wound and driven by the sprocket are in contact with the tip of the sprocket on the non-grounding surface side of the crawler belt. Since the members are in contact with each other, a gap is secured between the bush of the crawler belt and the tooth bottom portion of the sprocket to engage with each other. Therefore, the crawler belt link can maintain the state in which the bush does not contact the tooth bottom while the bush engages with the tooth of the sprocket and moves. Further, the contact member on the crawler belt side and the tooth tip of the sprocket are in contact with each other over a wide surface, and the engagement between the tooth portion and the bush can be maintained.
[0013]
According to the present invention, the crawler belt bushing can be engaged and driven in a state where it is not in contact with the bottom of the tooth. Therefore, when the bush meshes with the teeth, it can be prevented from rubbing with the earth and sand adhering to the bottom of the tooth, and large friction can be prevented. There is an effect that can be increased. Further, by making the tooth thickness slightly smaller than the size between the bushes of the crawler belt, both forward and backward driving forces can be performed at the tooth portion at the meshing position, so that it can be driven effectively even if the number of teeth is reduced. In addition, by increasing the tooth thickness, the contact surface with the contact member attached to the non-grounding surface side of the crawler belt can be widened, and the meshing of the crawler belt bush when it is away from the tooth bottom can be stably maintained. The strength of the part can be increased. Further, since the sprocket tooth is provided with a groove on the side surface in the centripetal direction, it penetrates into the crawler belt link at the position where the tooth portion and the contact member provided on the non-grounding surface side of the crawler belt contact each other. In this state, the earth and sand brought in are discharged from the groove portion to the outside without being compressed by the contact member and the tooth portion of the sprocket. Therefore, there is an effect that the sprocket replacement frequency can be reduced to improve the operation efficiency.
[0014]
The earth removal groove provided on the side surface of the tooth portion of the sprocket is preferably formed to expand from the tooth base toward the mounting portion side (second invention). In this way, when the sprocket teeth mesh with the crawler belt link, the earth and sand introduced into the link is discharged by the pressing force caused by the contact between the contact member attached to the crawler belt side and the tooth tip. At this time, by reducing the resistance to the discharge side, it is possible to obtain an effect that the soil is quickly discharged and the frictional resistance at the meshing portion due to earth and sand can be reduced.
[0015]
The sprocket may be composed of a plurality of segments divided at intermediate positions where the bushes and teeth of the crawler belt do not mesh with each other, and may be detachably attached to the drive wheels (third invention). In addition, the sprocket segment preferably includes a mounting portion that can be bolted from the outside to a hook-shaped mounting portion formed on the drive wheel (fourth invention). This makes it easy to assemble or replace, sometimes has the effect of partially replacing the segments, and reducing manufacturing costs.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific embodiment of the traveling drive device for a tracked vehicle according to the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a side view of a drive unit of a traveling drive device for a tracked vehicle according to the present invention. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is an enlarged front view of the sprocket teeth, and FIG. 4 is a view taken along line BB of FIG. .
[0018]
A travel drive device 1 according to this embodiment includes a crawler belt 3 wound around an idler (not shown) and drive wheels 2 on both sides of a body frame as a lower traveling body in a tracked vehicle (not shown). The crawler belt 3 which is attached and receives the power transmitted from the engine (not shown) and is wound around the driving wheel 2 through the reduction gear mechanism is driven. 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.
[0019]
The drive wheel 2 has a planetary gear speed reduction mechanism 6 supported at the end of the vehicle body frame with a well-known structure, a wheel 8 fixedly supported by the output shaft 7 and driven to rotate, and an outer periphery of the wheel 8 in a bowl shape. It is comprised with the cyclic | annular sprocket 20 with which the mounting part 8a formed is mounted | worn with a concentric circle.
[0020]
The wheel 8 is supported by a boss 6b of a casing 6a of the planetary gear reduction mechanism 6 via a rolling bearing 6c, and the output shaft of the planetary gear reduction mechanism 6 protrudes outside through the boss 6b. 7 (integrated with the carrier) are connected coaxially through a support ring 9 fitted and fixed by a spline key at the end. A plurality of sprocket mounting holes 11 are provided at a required radial position so as to be parallel to the axis at a predetermined pitch in the mounting portion 8a formed in a bowl shape.
[0021]
The sprocket 20 has a plurality of teeth, and as shown in FIG. 1, a bush that connects the link 4 between the tooth portion 21 and the tooth portion 21 (corresponding to a tooth valley). The tooth thickness dimension is increased by alternately forming the locations where one 5 is located and the locations where two 5 are located. And the tooth part 21 which meshes with the bush 5 of the link 4 is set as the structure used as the part in which any one tooth part 21 and the bush 5 are received in the part in which the said two bushes 5 are received. Therefore, as shown in FIG. 1, the bush 5 that does not contact the tooth portion 21 and the tooth surface are associated with each other so that a gap s that does not hinder driving is formed.
[0022]
The tooth portion 21 of the sprocket 20 has a tooth thickness T slightly smaller than the arc length obtained by subtracting the diameter of the bush 5 from the pitch of the pin 1 that substantially connects the link 4 of the crawler belt 3 to flatten the tooth tip 21a. Is formed. And the groove | channel 22 for earth removal of the width | variety is suitably formed in the side surface center part of the tooth | gear part 21 on both side surfaces. The groove 22 has a shape that widens from the tooth base toward the center of the wheel 8 (centripetal direction), so that earth and sand can be easily discharged.
[0023]
As shown in FIG. 1, the sprocket 20 according to the present embodiment is formed into an intermittent tooth shape every two teeth, and is divided at an intermediate position in the intermittent portion of the teeth to be divided into four segments. It is configured by combining. Therefore, each sprocket segment 20a consists of the same shape. The inner peripheral part of each sprocket segment 20a is formed in a stepped shape, and the rear side step part in the hooked mounting part 25 of the inner peripheral part is formed on the outer periphery of the mounting part 8a formed in the hooked shape of the wheel 8. A sprocket mounting hole 11 provided on the engagement surface of the hook-shaped mounting portion 8a of the wheel 8 by being engaged, and a mounting hole of the mounting portion 25 provided at a pitch matching the sprocket mounting hole 11 The nut 27 is screwed into the fastening bolt 26 inserted from the rear surface, and is fastened and fixed.
[0024]
In the crawler belt 3 with respect to the sprocket 20 having such a configuration, a rectangular contact member 30 is provided on the surface of the tooth tip 21a of the tooth portion 21 of the sprocket 20 on the non-ground surface side of the crawler plate 3a. It is fastened with bolts 35 from the outside so as to abut. When the link 4 meshes with the tooth portion 21 of the sprocket 20, the abutment member 30 contacts the non-grounded end surface 31 with the surface of the tooth tip 21 a, so that the bush 5 of the link coupling portion meshing with the tooth 21 is formed. The height dimension is set so as to be separated from the tooth bottom 23 by a required interval t.
[0025]
The travel drive device 1 of the present embodiment configured as described above receives power from a drive source and is decelerated to a required speed by the planetary gear mechanism 6 so that the sprocket 20 rotates together with the wheel 8. The crawler belt 3 wound around the sprocket 20 is driven by each tooth portion 21 except for the intermittent tooth portion of the sprocket when the link 4 moves and the bush 5 of the connecting portion meshes with the tooth portion 21 of the sprocket 20. The bush 5 meshes with the tooth surface in the rotational direction. Therefore, with regard to the meshing between the sprocket 20 and the link 4, the four teeth are substantially meshed with the eight teeth, and the power is transmitted at the locations where the teeth 21 come into contact with the teeth 21. However, since each tooth portion 21 can have a tooth thickness dimension larger than that of a general sprocket tooth, power can be transmitted reliably. The bush 5 in a position where it does not mesh with the tooth portion 21 does not receive a driving force directly in the tooth forming space portion, but an operation of connecting and moving the link 4 is performed.
[0026]
Further, when the link 4 of the crawler belt 3 meshes with the sprocket 20, the contact member 30 attached to the non-grounded side surface of the link 4 contacts and is received by the top surface of the tooth tip 21 a of the tooth portion 21 of the sprocket 20. Therefore, the meshing position of the bush 5 with respect to the tooth surface is defined. As a result, a gap t is always formed between the bush 5 and the tooth bottom 23, and the bush 5 can be rubbed against the earth and sand even if there is intrusion of earth and sand. In addition, the rubbing phenomenon can be reduced.
[0027]
Further, when the link 4 of the crawler belt 3 and the tooth portion 21 of the sprocket 20 are engaged, for example, when the earth and sand are engaged with each other in a state where soil and sand have entered and adhered to the non-grounding surface side of the crawler belt, in particular, the space inside the link 4, When the contact member 30 and the tooth portion 21 are engaged with each other, the earth and sand in the inner space portion of the link 4 is provided with the soil discharging grooves 22 on both side surfaces of the tooth portion 21, so that it is not consolidated inside. , It is pushed out by the groove 22. Since the groove 22 has a shape that expands from the tooth base toward the center of the wheel 8, the groove 22 is easily pushed out when pressed, and the soil is not consolidated inside the groove 22.
[0028]
Since the crawler belt 3 wound around the sprocket 20 is always supported and rotated by contact between the contact member 30 and the tooth tip 21a surface of the tooth portion 21, the thrust load is applied to the tooth tip surface. However, since the tooth portion 21 is formed with a tooth thickness T larger than usual, the tooth portion 21 can be driven while bearing a radial load and a traction load without any trouble. Therefore, it is not necessary to increase the diameter of the bush 5b or use an expensive material, and there is an advantage that the production cost on the crawler belt side can be reduced. Of course, the wear resistance of the sprocket 20 is improved and the frequency of replacement can be reduced.
[0029]
When the tooth portion 21 of the sprocket 20 is worn away and needs to be replaced after a long period of use, it is easy to disengage the divided sprocket segment 20a from the mounting bolt 26 and nut 27 to the wheel 8. Can be removed. In the fastening portion formed by the bolt 26 and the nut 27, each nut 27 is loosened on the front surface so that the fastening can be released and the sprocket segment 20a can be removed. It can be easily replaced on site.
[0030]
Next, FIG. 5 is a partially omitted front view showing another embodiment of the sprocket. In this embodiment, the basic configuration is the same as that of the above embodiment, and the sprocket structure is partially different. Therefore, the same structural parts as those of the above embodiment are denoted by the same reference numerals as those described above, and the description thereof is omitted.
[0031]
In this embodiment, the sprocket 20A has intermittent portions formed every other tooth, and is composed of six sprocket segments 20b divided at intermediate positions of the intermittent portions. Each of these sprocket segments 20b is a stepped mounting portion 25 formed on the inner peripheral portion, as in the above-described embodiment, and the stepped portion behind it is engaged with the outer periphery of the wheel 8, The bolts 26 and the nuts 27 are fastened through mounting holes provided so as to match the sprocket mounting holes provided on the eighth side.
[0032]
Since the sprocket 20A of such an embodiment is substantially the same as the sprocket 20 of the above-described embodiment, the same effects as those of the above-described embodiment are achieved. In addition, in sprocket 20A of this embodiment, since sprocket segment 20b for every tooth is combined, even if the situation where it breaks by any chance should arise, it can respond by exchanging only the part concerned. There is. Further, since all the sprocket segments 20b are divided and formed on the basis of the tooth portion 21, the sprocket segments 20b can be produced under the same conditions in manufacturing, and there is also an advantage that handling on the work becomes easy.
[0033]
As described above, according to the present invention, in a sprocket that is configured to be exchangeable when worn by operation, a portion that wears under the influence of earth and sand during meshing drive with a crawler belt link (bush) is strengthened and discharged. Since the earth function is added, it is possible to obtain a traveling drive device that can withstand long-term use and extend the replacement time.
[0034]
In addition, the flat surface of the tip of the sprocket in the present invention includes a flat surface, a convex curved surface, or a concave curved surface, and comes into contact with a contact member provided on the crawler belt side at a position where it meshes with the crawler belt link. It suffices to have a surface that can withstand the load.
[0035]
In addition, it goes without saying that this does not limit the present invention with respect to the reference numerals appended in the respective claims describing the constituent features of the present invention.
[Brief description of the drawings]
FIG. 1 is a side view of a drive unit of a traveling drive device for a tracked 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 front view of a tooth portion of a sprocket.
FIG. 4 is a BB view of FIG. 3;
FIG. 5 is a partially omitted front view showing another embodiment of the sprocket.
FIG. 6 is a front view showing a part of an example of a conventional travel drive device in section.
FIG. 7 is a side view showing, in section, a part of an example in a conventional travel drive device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Travel drive device 2 Drive wheel 3 Crawler belt 3a Crawler plate 4 Crawler belt link 5 Bush 6 Planetary gear mechanism 8 Wheel 8a Attachment part 11 Sprocket attachment hole 20, 20A Sprocket 20a, 20b Sprocket segment 21 Sprocket tooth part 21a Tooth tip 22 Exhaust Groove for earth 23 Tooth bottom 25 Sprocket mounting part 26 Bolt 30 Contact member 31 End surface of contact member

Claims (4)

In a traveling drive device for a tracked vehicle,
The sprocket (20) has a tooth thickness slightly smaller than the arc length between the bushes (5, 5) of the crawler belt (3) with which the tooth portion (21) meshes, and the tooth tip (21a) is formed on a flat surface. In addition, a groove (22) is provided in the centripetal direction on the side surface of the tooth portion (21), and the non-grounding surface side of the crawler belt (3) is in contact with the tooth tip (21a) of the tooth portion (21). A travel drive device for a tracked vehicle, wherein a contact member (30) for ensuring a gap is provided between the bush (5) and a tooth bottom portion (23) of the sprocket (20). The traveling drive of the tracked vehicle according to claim 1, wherein the earth removing groove (22) provided on the side surface of the tooth portion of the sprocket (20) is formed to expand from the tooth base toward the mounting portion side. apparatus. The sprocket (20) is composed of a plurality of segments divided at an intermediate position where the bush (5) and the tooth portion (21) of the crawler belt (3) do not mesh with each other, and is detachably attached to the drive wheel (2). The traveling drive apparatus for a tracked vehicle according to claim 1 or 2, wherein the traveling drive apparatus is configured. The sprocket segment (20a, 20b) is provided with a mounting portion that can be detachably bolted from the outside to a hook-shaped mounting portion (8a) formed on the drive wheel (2). Driving device for a tracked vehicle.

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