Patent Application
20060082218
This application claims priority to Korean Patent Application No. 10-2004-82181, filed Oct. 14, 2004, which is incorporated herein by reference in its entirety.
The present invention relates to an undercarriage equipped with a non-steel type rubber crawler using chain action, particularly to an undercarriage of a track system for a skid loader in which an auxiliary sprocket axis and an auxiliary sprocket are equipped to solve load concentration at the contact of a non-steel type rubber crawler, which is adopted to reduce total load of a vehicle, and cogs of a sprocket and a gearchain is equipped surrounding a main sprocket axis and the auxiliary sprocket axis, so that it receives the load dispersed over the large contact area of the non-steel type rubber crawler, thereby relieving internal stress concentration at the sprocket and the non-steel type rubber crawler and significantly improving life cycle of the non-steel type rubber crawler.
In general, heavy vehicles such as skid loader, excavator, bulldozer, etc. have an undercarriage part supporting the top part and transferring it to a wanted position.
Typically, a crawler is used in the undercarriage for efficient transportation of a heavy vehicle on rough or unstable ground. Recently, a rubber crawler is widely used to reduce vibration and noise during transpiration and minimize road damage.
Usually, the rubber crawler has a steel core inside the rubber track, which receives power from sprocket and the idler. But, with regard to improvement in bending ability of the rubber crawler and reduction of vehicle weight, a non-steel type rubber crawler without a steel core is proposed.
As seen in
The non-steel type rubber crawler 10 comprises a belt body having a closed-loop shape, pull lugs 11 formed on the outer surface of the belt body and protruding teeth 12 formed on the inner surface of the belt body. The sprocket 20, which receives rotational driving force from main axis 40, has protruding cogs 21 at the outer circumference. As they are geared with protruding teeth 12 at the inside of the non-steel type rubber crawler 10, the rotational driving force is transferred, so that the non-steel type rubber crawler 10 moves forward or backward. Then, the non-steel type rubber crawler 10 rotates along with track roller 50 at the bottom and idler 60 in the rear, moving forward or backward distributing the weight load of the vehicle uniformly to the ground surface.
In such an undercarriage, the most loaded parts are the cogs 21 where the sprocket 20 is geared with the non-steel type rubber crawler 10 and the point where the non-steel type rubber crawler 10 contacts the ground.
There are some researches on dynamic analysis at the point where the non-steel type rubber crawler 10 contacts the ground and distribution of internal stress thereabout. To take an example, Korean Patent Application No. 2002-0026894 (Rubber crawler and rubber crawler driving apparatus) reduces rigidity difference of less rigid first lug part and more rigid second lug part by lessening thickness of the second lug along the belt body direction smaller than that of the first lug part. As a result, deformation of the crawler is reduced, thereby reducing vibration and improving riding comfort.
On the other hand, there is no research on dynamic analysis at the cogs 21 where the sprocket 20 is geared with the non-steel type rubber crawler 10 (A-A′ in
Although there is advantage of improvement of bending ability of the rubber crawler and reduction of vehicle weight when the non-steel type rubber crawler 10 is used for an undercarriage, the non-steel type rubber crawler is difficult to equip and stress tends to be concentrated at specific points (see
Accordingly, it is required to relieve stress at the contact of the non-steel type rubber crawler and the sprocket in heavy vehicles like skid loader as friction between the vehicle and the ground is transferred to the rubber crawler, thereby reducing stress-induced deformation and improving life cycle and durability.
It is an object of the present invention to relieve stress at the contact of a non-steel type rubber crawler, which is adopted in an undercarriage of a heavy vehicle like skid loader to reduce load by the vehicle weight, and a sprocket, thereby reducing stress-induced deformation the rubber crawler and improving life cycle and durability.
It is another object of the invention to offer more efficient and stable transfer of driving force between the non-steel type rubber crawler and the sprocket, thereby improving riding comfort.
Other objects of the invention will be described in more detail herein below.
The undercarriage equipped with a non-steel type rubber crawler using chain action according to the present invention is characterized by comprising a rubber crawler inside of which is contacted by a rotating sprocket, an idler rotated by the rubber crawler, a track roller, a rotatable auxiliary sprocket contacting inside of the rubber crawler as spaced from a main sprocket axis and a gearchain outside of which contacts inside of the rubber crawler and inside of which contacts outside of the sprocket and the auxiliary sprocket, thereby preventing load concentration at the sprocket.
Preferably, gear ratio of the sprocket and the auxiliary sprocket is set to 2:1 for efficient stress dispersion.
And, preferably, the undercarriage may further comprise at least one supporting axis between the main axis and the auxiliary axis and a supporting sprocket having cogs that gear with the gearchain at both ends of the supporting axis in order to prevent the gearchain from being suspended downward because of the long distance from the main axis and the auxiliary axis and the weight of the gearchain and to prevent non-uniform contact of the gearchain with the non-steel type rubber crawler.
Preferably, the supporting axis and the supporting sprocket are located in between the main axis and the auxiliary axis. More supporting axis and supporting sprocket may be added when the distance between the main axis and the auxiliary axis is increased to increase contact area of the gearchain and the non-steel type rubber crawler.
Hereunder is given a detailed description of a preferred embodiment of the present invention referring to the attached drawings. In the description, known matters that are considered unnecessary in describing the invention will not be described in detail.
The terms were selected considering the roles in the present invention. The terms need to be defined based on the overall contents of this specification, since they may be used differently depending on users and practices.
Description of non-steel type rubber crawler 10 having protruding teeth 12 on the inside, track roller 50 and idler 60 will be omitted because they are the same as those of a conventional undercarriage. Auxiliary axis 30, auxiliary sprocket 80 and gearchain 70, which are key constituents of the invention, are shown in
Sprocket 20 is receives rotational driving force from main axis 40. It has cogs 21 spaced at a given interval on the outer circumference. The auxiliary axis 30 is spaced from the main axis 40 at a given interval. Each end of the auxiliary axis is axis-joined with the auxiliary sprocket 80 auxiliary cogs spaced at a given interval on the outer circumference.
In the embodiment, gear ratio, or the ratio of number of the cogs 21 of the sprocket 20 to that of the cogs 31 of the auxiliary sprocket 80, is 12:6, or 2:1, as seen in
The gearchain 70 receives rotational driving force from the cogs 21 of the sprocket 20, which receive rotational driving force from the main axis 40. As the gearchain 70 rotates, so does the auxiliary sprocket 80 at the auxiliary axis 30.
The portion of the gearchain 70 where the cogs 21, 31 of the sprocket 20 and the auxiliary sprocket 30 are rotated by the gearchain, i.e., section B-B′ in
While rotational driving force is transferred at a limited portion of the cogs 21 of the sprocket 20 (section A-A′ of
Section B-B′ of
The more the number of the supporting axis 90 and the supporting sprocket 91 between the main axis 40 and the auxiliary axis 30, the farther can be the auxiliary axis 30 from the main axis 40, providing larger contact area of the gearchain 70 with the non-steel type rubber crawler 10 and improving stress dispersion and durability.
While the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that various modifications and substitutions can be made thereto without departing from the spirit and scope of the invention.
The present invention offers the advantage of relieving stress concentration at between the non-steel type rubber crawler and the sprocket when driving a heavy vehicle like a skid loader and the consequent stress accumulation by increased contact area with the gearchain, thereby reducing deformation and stress of the protruding teeth, improving durability and extending life cycle.
Also, stable and efficient power transfer by the gearchain between the non-steel type rubber crawler and the sprocket offers improved riding comfort.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2004-82181 | Oct 2004 | KR | national |
