JP7394698B2 - Rubber crawler starting wheel, drive mechanism, and vehicle - Google Patents

Description

The present disclosure relates to a starting wheel, a drive mechanism, and a vehicle.

BACKGROUND OF THE INVENTION Endless tracks have been widely put into practical use primarily as devices for smooth movement of vehicles over rough terrain. The endless track has a belt shape that is wound around a starting wheel, a guide wheel, and a rolling wheel provided on both sides of the vehicle in the width direction, and is driven by the starting wheel to roll in the winding direction. Traditionally, endless tracks have been made of metal, but in recent years, they are increasingly being made of rubber to reduce weight and cost. This type of endless track is called a crawler (or rubber crawler).

There are two ways to drive the rubber crawler: one uses the frictional force between the cylindrical surface of the starting wheel and the rubber crawler, the other uses the teeth of the starting wheel to engage the rubber crawler, and a combination of these methods. It has been put into practical use so far. In either method, the driving wheel itself is generally made of resin.

Japanese Patent Application Publication No. 7-205852

However, when the starting wheel is made of resin, there is a problem in that it is difficult to obtain a frictional force between the cylindrical surface and the rubber crawler, and furthermore, the cylindrical surface and the tooth portion are likely to wear out.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a starting wheel, a drive mechanism, and a vehicle that have high transmission torque and are less prone to wear.

In order to solve the above problems, a starting wheel of a rubber crawler according to the present disclosure includes a sprocket part that is annular around an axis and has a plurality of teeth arranged in the circumferential direction, and a sprocket part that is coaxial with the sprocket part. and a ring part that is integrally provided and whose outer circumferential surface is a cylindrical surface having an outer diameter larger than the maximum outer diameter of the sprocket part around the axis , and a tooth part of the sprocket part. The friction coefficient of the cylindrical surface of the ring part is larger than the friction coefficient of the surface of the ring part.

According to the present disclosure, it is possible to provide a starting wheel for a rubber crawler , a drive mechanism, and a vehicle that have high transmission torque and are less prone to wear.

1 is a side view of a vehicle according to an embodiment of the present disclosure. FIG. 2 is a front view of a driving wheel according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view of a driving wheel according to an embodiment of the present disclosure.

(Vehicle configuration)
Hereinafter, a vehicle 100 including a starting wheel 11 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. Vehicle 100 is a transportation machine used primarily for the purpose of moving over rough terrain. As shown in FIG. 1, the vehicle 100 includes a vehicle body 1 and a drive mechanism 2.

The vehicle body 1 includes an upper vehicle body 1A that accommodates passengers, luggage, etc., a lower vehicle body 1B that accommodates an engine, a transmission, etc., and a plurality of wheels provided on both sides of the lower vehicle body 1B in the width direction. There is. More specifically, one starting wheel 11, one guiding wheel 12, a plurality (for example, five) of lower rolling wheels 13A, and a plurality of (for example, five) upper rolling wheels 13B. It is provided. The starting wheel 11 is attached to the front end of the lower part 1B of the vehicle body. The starting wheel 11 has a plurality of teeth 21 (described later) that engage with a crawler 3 (rubber crawler) described later. The starting wheel 11 and the crawler 3 constitute a drive mechanism 2. The starting wheel 11 is rotationally driven around a rotation axis extending in the width direction of the vehicle 100 by power transmitted from the engine. Note that in the following description, the width direction of the vehicle 100 will be simply referred to as the "width direction."

The guide wheel 12 is provided at the end of the lower part of the vehicle body 1B on the opposite side to the starting wheel 11. The guide wheel 12 is rotatable around a rotation axis extending in the width direction. In other words, no power is applied to the guide wheels 12. The lower roller 13A is provided at the lower part of the vehicle body lower part 1B, and is rotatable around a rotation axis extending in the width direction while supporting the load of the vehicle body 1. The upper roller wheel 13B is provided above the lower roller wheel 13A and between the starting wheel 11 and the guide wheel 12 in order to prevent the crawler 3 from hanging down.

(Crawler configuration)
A crawler 3 serving as an endless track is wound around these starting wheels 11, guide wheels 12, lower rollers 13A, and upper rollers 13B so as to surround them from the outside. More specifically, the crawler 3 extends from the starting wheel 11 to the guiding wheel 12 via the upper rolling wheel 13B, and from the guiding wheel 12 to the starting wheel 11 via the lower rolling wheel 13A. In the following description, the direction in which the crawler 3 extends will be referred to as the "winding direction."

The crawler 3 has a plurality of track plates 3B mainly made of rubber. The crawler 3 can be freely curved in a plane perpendicular to the width direction. By rotating the starting wheel 11 while the claws of the starting wheel 11 are engaged with the crawler 3, driving force is applied to the crawler 3. That is, the crawler 3 rolls toward either side in the winding direction. In addition, the driving method of the crawler 3 is not limited to the above, and it is also possible to adopt a method in which the crawler 3 is driven by, for example, the lower roller 13A or the upper roller 13B. Further, it is also possible to adopt a configuration in which the guide wheel 12 is not provided.

For example, the crawler 3 is divided into a plurality of parts at an intermediate position in the winding direction. That is, the annular crawler 3 is formed by connecting a plurality of units having a certain unit length. Note that the annular crawler 3 may be configured by connecting both ends of one continuous unit.

(Composition of starting wheel)
Next, the configuration of the driving wheel 11 will be described with reference to FIGS. 2 and 3. The starting wheel 11 includes a wheel body 10, a sprocket portion 20, a ring portion 30, a holding plate 40, and a bolt 41.

The wheel body 10 has a cylindrical shape centered on an axis Ac extending in the width direction. As shown in FIG. 3, the wheel body 10 includes a pair of cylindrical portions 10A, a pair of reduced diameter portions 10B, a pair of bottom portions 10C, and a pair of collar portions 10D. The pair of cylindrical portions 10A have a cylindrical shape centered on the axis Ac, and are spaced apart from each other in the width direction. The reduced diameter portion 10B has a conical shape that gradually reduces in diameter from the opposing edges of the pair of cylindrical portions 10A toward the center in the width direction. The bottom portion 10C has a disk shape centered on the axis Ac, and connects the pair of reduced diameter portions 10B to each other. A collar portion 10D is provided on the outer circumferential surface of the cylindrical portion 10A at a position biased toward the reduced diameter portion 10B. The flange portion 10D has an annular shape centered on the axis Ac.

One sprocket portion 20 is provided on the outer peripheral surface of each cylinder portion 10A. As shown in FIG. 2, the sprocket portion 20 has an annular shape centered on the axis Ac, and has a plurality of teeth 21 arranged in the circumferential direction. These teeth 21 engage with recesses formed in the edge of the crawler 3. Each tooth portion 21 projects radially outward. The sprocket portion 20 is formed by integrally connecting these tooth portions 21 in an annular shape centered on the axis Ac. The sprocket portion 20 is press-fitted into the cylindrical portion 10A. Although not shown in detail, a key is provided on the inner peripheral side of the tooth portion 21 to engage with a key groove formed in the cylindrical portion 10A. Furthermore, the sprocket portion 20 is made of a resin material. Note that it is also possible to form the sprocket portion 20 with a metal material having a different coefficient of friction from that of the crawler 3.

The ring portion 30 is coaxially mounted adjacent to the sprocket portion 20 on the outer circumferential surface of the cylinder portion 10A. More specifically, one ring part 30 is arranged inside each of the pair of sprocket parts 20. The ring portion 30 includes a cylindrical portion 31 having a cylindrical shape centered on the axis Ac, and an annular support portion 32 extending inward from an edge of the cylindrical portion 31. The outer peripheral surface of the cylindrical portion 31 is a cylindrical surface 31S centered on the axis Ac. This cylindrical surface 31S abuts against the inner surface of the crawler 3 with a frictional force. That is, in this drive mechanism 2, the crawler 3 is caused to roll by the engagement by the sprocket portion 20 described above and the frictional force by the ring portion 30. The ring portion 30 is made of a metal material or a resin material that has a larger coefficient of friction than the resin material forming the sprocket portion 20. In other words, the friction coefficient of the cylindrical surface 31S is set to be larger than that of the surface of the tooth portion 21. Note that in order to realize such a difference in the coefficient of friction, in addition to the configuration using different materials as described above, it is also possible to use the same material but with different surface roughness. It is also possible to adopt a configuration in which the surface roughness is further varied using different materials. In other words, the sprocket portion 20 and the ring portion 30 may be formed of materials having different surface friction coefficients.

The ring portion 30 and the sprocket portion 20 are fitted into the cylindrical portion 10A of the wheel body 10 in this order from the outside in the width direction. In this state, the presser plate 40 is attached to the outer surface of the sprocket portion 20. The holding plate 40 has an annular shape centered on the axis Ac. The presser plate 40 is coupled to the end 10E of the cylindrical portion 10A by bolts 41. Note that the end portion 10E is an annular end surface of the cylindrical portion 10A that faces in the direction of the axis line Ac. The sprocket part 20 and the ring part 30 are held between the presser plate 40 and the collar part 10D. In other words, by removing the bolts 41, the sprocket portion 20 and the ring portion 30 can be respectively removed.

(effect)
Next, the operations of vehicle 100 and crawler 3 will be explained. In order to move the vehicle 100, the starting wheel 11 is first rotated by the engine. The tooth portion 21 of the starting wheel 11 engages with the crawler 3, and driving force is applied to the crawler 3 by rotating the starting wheel 11 while the ring portion 30 is in frictional contact with the crawler 3. Thereby, the crawler 3 rolls toward either side in the winding direction. As a result, propulsion force is provided to vehicle 100.

Here, if the starting wheel 11 is integrally formed only with resin, it is difficult to obtain a frictional force between the cylindrical surface 31S and the crawler 3, and furthermore, wear easily progresses between the cylindrical surface 31S and the tooth portion 21. There is a possibility. However, according to the above configuration, the friction coefficient of the cylindrical surface 31S is larger than the friction coefficient of the surface of the tooth portion 21 of the sprocket portion 20. Thereby, it is possible to ensure a large frictional force generated between the cylindrical surface 31S and the crawler 3, and to suppress the frictional force generated between the toothed portion 21 and the crawler 3 to be small. Thereby, the ratio of torque transmission by the ring part 30 among the torque transmission by the sprocket part 20 and the ring part 30 can be increased, so that wear of the tooth part 21 can be suppressed. As a result, wear and tear on the starting wheel 11 as a whole can be reduced, and the vehicle 100 can be stably operated over a longer period of time.

According to the above configuration, since the sprocket portion 20 is formed of a resin material, the weight of the entire driving wheel 11 can be kept small. Furthermore, since the ring portion 30 is formed of a metal material, wear of the ring portion 30 can be kept to a small level even when a large load is applied under a high torque transmission ratio.

According to the above configuration, since the sprocket portion 20 and the ring portion 30 are removable from the wheel body 10, they can be easily replaced when the sprocket portion 20 and the ring portion 30 become worn. I can do it. Thereby, the maintainability of the vehicle 100 can be further improved.

(Other embodiments)
Although the embodiment of the present disclosure has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and may include design changes without departing from the gist of the present disclosure. For example, in the embodiment described above, the sprocket portion 20 is provided outside the ring portion 30. However, it is also possible to employ a configuration in which the sprocket portion 20 is provided inside the ring portion 30.

<Additional notes>
The starting wheel 11, drive mechanism 2, and vehicle 100 described in each embodiment are understood as follows, for example.

(1) The starting wheel 11 according to the first aspect includes a sprocket part 20 having a ring shape centered on the axis Ac and having a plurality of teeth 21 arranged in the circumferential direction, and a sprocket part 20 that is coaxial with the sprocket part 20 and has a plurality of teeth 21 arranged in the circumferential direction. It has a ring part 30 that is integrally provided and whose outer peripheral surface is a cylindrical surface 31S centered on the axis Ac, and the friction coefficient of the surface of the tooth part 21 of the sprocket part 20 is higher than the friction coefficient of the surface of the tooth part 21 of the sprocket part 20. The coefficient of friction of the cylindrical surface 31S of the ring portion 30 is large.

According to the above configuration, the friction coefficient of the cylindrical surface 31S of the ring part 30 is larger than the friction coefficient of the surface of the tooth part 21 of the sprocket part 20. Thereby, it is possible to ensure a large frictional force generated between the cylindrical surface 31S and the crawler 3, and to suppress the frictional force generated between the toothed portion 21 and the crawler 3 to be small. Thereby, the ratio of torque transmission by the ring part 30 among the torque transmission by the sprocket part 20 and the ring part 30 can be increased, so that wear of the tooth part 21 can be suppressed.

(2) In the starting wheel 11 according to the second aspect, the sprocket portion 20 and the ring portion 30 are formed of materials having different surface friction coefficients.

According to the above configuration, since the sprocket part 20 and the ring part 30 are formed of materials with different surface friction coefficients, wear can be kept to a minimum even when a large load is applied at a high torque transmission ratio. be able to.

(3) The starting wheel 11 according to the third aspect includes a cylindrical wheel body 10 centered on the axis Ac, the sprocket part 20 detachably attached to the wheel body 10, and the ring part 30. and has.

According to the above configuration, since the sprocket portion 20 and the ring portion 30 are removable from the wheel body 10, they can be easily replaced when the sprocket portion 20 and the ring portion 30 become worn. I can do it.

(4) The drive mechanism 2 according to the fourth aspect includes a starting wheel 11 and a rubber crawler (crawler 3) that is driven while being wound around the starting wheel 11.

According to the above configuration, the drive mechanism 2 can be operated stably over a long period of time by providing the starting wheel 11 that is less prone to wear.

(5) The vehicle 100 according to the fifth aspect includes a drive mechanism 2 and a vehicle body 1 driven by the drive mechanism 2.

According to the above configuration, it is possible to provide the vehicle 100 that can be operated more stably over a long period of time.

100 Vehicle 1 Car body 1A Car body upper part 1B Car body lower part 2 Drive mechanism 3 Crawler 10 Wheel body 10A Cylindrical part 10B Reduced diameter part 10C Bottom part 10D Flange part 10E End part 11 Starting wheel 12 Guide wheel 13A Lower roller wheel 13B Upper roller wheel 20 Sprocket part 21 Tooth portion 30 Ring portion 31 Cylindrical portion 31S Cylindrical surface 32 Support portion 40 Holding plate 41 Bolt Ac Axis

Claims (5)

a sprocket part having a ring shape centered on the axis and having a plurality of teeth arranged in the circumferential direction;
a ring portion that is coaxially and integrally provided with the sprocket portion and has an outer circumferential surface that is a cylindrical surface having an outer diameter larger than a maximum outer diameter of the sprocket portion around the axis ;
has
A starting wheel for a rubber crawler, wherein the friction coefficient of the cylindrical surface of the ring part is larger than the friction coefficient of the surface of the teeth of the sprocket part. The starting wheel for a rubber crawler according to claim 1, wherein the sprocket portion and the ring portion are formed of materials having different surface friction coefficients. a cylindrical wheel body centered on the axis;
The sprocket portion and the ring portion are removably attached to the wheel body;
The starting wheel for a rubber crawler according to claim 1 or 2, comprising: The starting wheel according to any one of claims 1 to 3;
a rubber crawler that is driven while being wound around the starting wheel;
A drive mechanism comprising: The drive mechanism according to claim 4;
a vehicle body driven by the drive mechanism;
A vehicle equipped with

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