Link seal for an infinite track and method for manufacturing the same

Abstract

The present invention relates to a link seal for an endless track truck and a manufacturing method thereof. When manufacturing the link seal, a shape restoring portion for partially or entirely doubling the restoring force is integrally formed with the body of the link seal, thereby eliminating the need to further fit in a separate ring-shaped shape restoring member. This eliminates the need for assembly of the link seal itself, and the structure is simple. In addition, there is no slack in the ring-shaped shape restoring member, so the restoring force of the link seal can be maintained for a long period of time. This provides a link seal for an endless track truck and a manufacturing method thereof that can significantly reduce the manufacturing costs of the link seal.

Description

Technical Field

[0001] The present invention relates to a link seal for an endless track and a method for manufacturing the same. More specifically, the present invention relates to a structure of a link seal mounted on a track shaft of an endless track-shaped track mounted on a tank, an armored vehicle, a bulldozer, an excavator, etc., which improves the resilience of the link seal transmitted in the axial direction of the bush due to compression and expansion and maintains it over a long period of time, while reducing the manufacturing cost and having a structure that is easy to assemble. The present invention relates to a link seal for an endless track and a method for manufacturing the same.

Background Art

[0002] Generally, an endless track vehicle is a vehicle that runs on two endless tracks (caterpillars) attached one on each side of the vehicle body, and examples include tanks, armored vehicles, bulldozers, excavators, etc. An endless track is a device in which a steel belt is wound around a wheel, and because the contact surface with the ground is large, it can run on steep roads, slopes, etc.

[0003] Conventionally, such an endless track is provided with a link seal that prevents leakage of oil or the like injected into the internal friction portion of the joint where the inner and outer links are joined. The inner link and the outer link are joined by a fixing pin, a bush is joined to the outside of the fixing pin, and a link seal is fitted between the tip of the outer link and the bush. A link joint sealing device for an endless track in which a pair of link seals are fitted in different directions has been proposed in Japanese Utility Model Publication No. 54-17541 (Reference 1).

[0004] However, in the technology proposed in the above Reference 1, although the link seal inserted between both ends of the outer link and the bush has a buffering function to some extent of compressing and expanding when the impact force associated with the transfer on the endless track is transmitted, when a strong impact force acts in the axial direction of the bush, the link seal cannot properly respond to the impact force. As a result, the function of retaining the lubricating oil injected inside without leakage due to damage to the parts or wear due to friction deteriorates, and it becomes necessary to replenish the lubricating oil at any time. When foreign matter flows in from the outside, there are problems such as shortened lifespan.

[0005] Needless to say, in order to solve the problems of Reference 1 as described above, Korean Registered Patent No. 10-2322467 (Reference 2) has been proposed. Reference 2 relates to a link seal for an endless track in which restoring rings are disposed on the inner and outer surfaces of the link seal to double the restoring force in the compressed state of the link seal due to the load and impact transmitted in the axial direction of the bush.

[0006] However, Reference 2 has drawbacks in that the link seal and the restoring ring are manufactured separately, and by fitting the restoring ring on the inner and outer surfaces of the link seal, not only is the work complicated, but the assembly time is prolonged and the manufacturing cost is also high.

[0007] In addition, when the link seal in a state where the restoring ring is disposed as described above is fitted into the fixing pins disposed on the inner and outer links and the link seal is compressed and expanded by the impact force in the axial direction of the bush, there is a problem that the restoring force of the link seal becomes weak due to the slack of the restoring ring supported by the link seal. Summary of the Invention Problems to be Solved by the Invention

[0008] Therefore, in order to solve the problems of such conventional technologies, the present invention improves the structure of a link seal mounted on a track axle of an endless track type track mounted on a tank, armored vehicle, bulldozer, excavator, etc., and transmits the compression and expansion in the axial direction of the bush. An object of the present invention is to provide a link seal for an endless track type track and a manufacturing method thereof that can reduce manufacturing costs while maintaining the restoring force of the link seal over a long period of time.

[0009] In particular, the present invention integrally forms a restoring ring in the link seal without separately manufacturing it, and in a state where the link seal is fitted into fixing pins arranged on the inner and outer links, even if the compression and expansion of the link seal due to an impact force are repeatedly performed in the axial direction of the bush, An object of the present invention is to provide a link seal for an endless track type track and a manufacturing method thereof that can prevent weakening of the restoring force of the link seal over a long period of time.

Means for Solving the Problems

[0010] In order to solve such technical problems, the present invention has a donut shape, but has a fitting hole drilled in the center of the inner side, a support portion protruding in the center on the outer side, and a close contact space portion having a predetermined space on both sides of the support portion. A link seal body in which the first and second elastic portions protrude so as to be separated from each other, and a shape restoring portion integrally formed with the link seal body to double the restoring force of the link seal body. A molding groove having a narrow support claw at the entrance is formed at the inner end of the close contact space portion of the link seal body so as to prevent the separation of the shape restoring portion, and the shape restoring portion is formed in the molding groove of the link seal body by ethylene propylene diene monomer (EPDM). It is characterized by being integrally joined by double injection.

[0011] In addition, the manufacturing method of a link seal for a tracked truck of the present invention includes a first step of molding a link seal body using a first synthetic resin material, the link seal body being donut-shaped, with an insertion hole drilled in the center on the inside, a support part protruding in the center on the outside, and first and second elastic parts protruding apart so as to have a contact space part with a predetermined space on both sides of the support part, and a second step of molding a shape restoring part by double injection of a second synthetic resin material, ethylene propylene diene monomer (EPDM), into part or all of the link seal body, wherein in the first step, a molding groove having a support claw with a narrow entrance is formed at the inner end of the contact space part of the link seal body to prevent the shape restoring part from coming off. Effect of the Invention

[0012] According to the present invention, when manufacturing a link seal, a shape restoring portion for doubling the restoring force partially or entirely is integrally formed with the link seal body, thereby eliminating the need to further fit in a separate ring-shaped shape restoring member. This eliminates the need for assembly of the link seal itself, simplifies the structure, and there is no slack in the ring-shaped shape restoring member, allowing the link seal's restoring force to be maintained for a long period of time.

[0013] In addition, according to the present invention, it is not necessary to fabricate a separate ring-shaped shape restoring member, and while it is possible to form a shape restoring portion for doubling the restoring force of the link seal body in various shapes through double injection, it is not necessary to fabricate and fit a separate ring-shaped shape restoring member, which has the advantage of significantly reducing the manufacturing costs of the link seal. [Brief description of the drawings]

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the features should be understandable from embodiments in which a link seal for an endless track according to the present invention and a method for manufacturing the same will be described in detail based on the accompanying drawings.

[0016] FIGS. 1 to 4 are diagrams shown for explaining a link seal for an endless track according to a first embodiment of the present invention.

[0017] Referring to the same figure, a link seal 100 for an endless track according to the present invention is fitted into a fixing pin 3 penetrating through a pair of inner and outer links 1 and 2 of an endless track vehicle, and is installed between the outer link 2 and the tip of a bush 4 to perform buffering and prevent oil leakage.

[0018] Such a link seal 100 of the present invention has a donut shape, but an insertion hole 111 through which the fixed pin 3 of the infinite track penetrates is formed in the inner center, and a support portion 112 protrudes in the center on the outside. A link seal body 110 in which first and second elastic portions 114 and 115 protrude so as to be separated from each other with a close contact space portion 113 having a predetermined space on both sides of the support portion 112, and a shape restoration portion 120 integrally formed on part or all of the link seal body 110 to double the restoring force of the link seal body 110.

[0019] In this case, the link seal 100 is manufactured by first molding the link seal body 110 using a first synthetic resin material and then secondarily double-injecting the shape restoration portion 120 using a second synthetic resin material onto the link seal body 110.

[0020] Hereinafter, the present invention will be described in detail.

[0021] First, the link seal body 110 has a donut shape, an insertion hole 111 through which the fixed pin 30 of the infinite track penetrates is formed in the inner center, a support portion 112 protrudes in the center on the outside, the first and second elastic portions 114 and 115 are continuous on both sides of the support portion 112, and a close contact space portion 113 having a predetermined space is continuously provided between the support portion 112 and the first and second elastic portions 114 and 115. Needless to say, a close contact space portion may be further continuously provided on the inner surface of the insertion hole 111.

[0022] At this time, the support portion 112 may be inclined in both directions from the upper end portion, or may be provided in various shapes.

[0023] And the first and second elastic portions 114 and 115 may have a predetermined thickness, extend from both end portions of the support portion 112, and be formed to incline at a predetermined angle, or may be formed vertically. Needless to say, the first and second elastic portions 114 and 115 are not limited thereto and may exhibit various shapes.

[0024] Further, it goes without saying that the close contact space portion 113 formed between the support portion 112 and the first and second elastic portions 114 and 115 can exhibit various shapes according to the support portion 112 and the first and second elastic portions 114 and 115.

[0025] Such a link seal body 110 is preferably injection-molded from a first synthetic resin material. As the first synthetic resin material, a high-strength resin material having elasticity, for example, polycarbonate (PC), can be used. However, the resin material is not limited thereto, and various known materials having elasticity can be adopted.

[0026] On the other hand, the shape restoring portion 120 is integrally formed in part or all of the close contact space portion 113 of the link seal body 110 to double the restoring force of the link seal body 110. The shape restoring portion 120 is preferably formed by double injection into the link seal body 110 from a second synthetic resin material. As the second synthetic resin material, synthetic rubber, for example, ethylene propylene diene monomer (EPDM: Ethylene-Propylene Diene Monomer), can be used.

[0027] The ethylene propylene diene monomer (EPDM) is a material having excellent durability and is similar in that the rubber material is resistant to high temperatures. However, it has the advantage of being excellent in low-temperature compatibility. Needless to say, various materials including rubber or silicon materials and having substantially the same physical properties can be equally adopted as the second synthetic resin material.

[0028] Such a shape restoring portion 120 is integrally formed inside the close contact space portion 113 of the link seal body 110 and at the boundary portion between the support portion 112 and the first and second elastic portions 114 and 115. Needless to say, when a close contact space portion is further continuously provided inside the insertion hole 111, a shape restoring portion may be further formed.

[0029] More specifically, in order to prevent the shape restoration part 120 from being removed from the link seal body 110 during use due to the heterogeneity between the first and second synthetic resin materials forming the link seal body 110 and the shape restoration part 120, when the link seal body 110 is injection-molded for the first time, a molding groove 116 having a support claw 116a with a narrow inlet is formed at the inner end of the close contact space part 120. Next, the molten secondary synthetic resin is injected into the molding groove 116 of the link seal body 110 through secondary double injection and cured to form the shape restoration part 11.

[0030] In this case, the molding groove 116 has a circular structure with an opening formed in its cross-section. Therefore, it is preferable that the shape restoration part 120 is formed to have an overall ring shape with a circular cross-section. Needless to say, the cross-sections of the molding groove 116 and the shape restoration part 120 are not limited to this, and they may be molded to have various cross-sectional shapes such as semi-circular, triangular, diamond-shaped, trapezoidal, etc. Such a design change to this extent also belongs to the scope of the rights of the present invention.

[0031] When such a shape restoration part 120 is integrally formed in the molding groove 116 of the link seal body 110, it is supported by the support claw 116a so as to prevent detachment, and it is also possible to prevent the shape restoration part 120 from being removed from the link seal body 110 when the link seal 100 is compressed and expanded.

[0032] As described above, if the shape restoration part 120 is formed in the molding groove 116 of the link seal body 110 through double injection, it is not necessary to further fit a separate ring-shaped shape restoration member. Therefore, the assembly work of the link seal 100 itself is unnecessary, the structure is simple, and since there is no slack in the ring-shaped shape restoration member, the restoring force of the link seal 100 can be maintained for a long time, and the manufacturing cost of the link seal 100 can also be significantly reduced.

[0033] On the other hand, FIG. 5 is a diagram shown to explain the link seal of the track for an endless track according to the second embodiment of the present invention.

[0034] According to this, when forming the shape restoration part 120 in the molding groove 116 of the link seal body 110 through double injection molding, by further extending the locking projection 121 that protrudes outside the support claw 116a to make the connection between the molding groove 116 of the link seal body 110 and the shape restoration part 120 even stronger, it is possible to prevent the shape restoration part 120 from being removed (detached) from the molding groove 116 of the link seal body 110.

[0035] Although only the locking projection 121 of the shape restoration part 120 with an end in a straight shape is shown, it is needless to say that it is not limited thereto, and the end of the locking projection 121 may be designed and formed to have various cross-sectional shapes such as a dome-shaped structure with a protruding center.

[0036] And FIG. 6 is a diagram shown to explain the link seal for an endless track according to the third embodiment of the present invention.

[0037] According to this, the shape restoration part 120 may be formed with a constant set thickness (for example, 0.5 to 1.0 mm) throughout along the outer surface of the link seal body 110. As an example, the shape restoration part 120 can be formed with a uniform thickness by double injection molding of ethylene propylene diene monomer (EPDM), which is a second synthetic resin material, into the support part 112 forming the close contact space part 113 and the first and second elastic parts 114, 115.

[0038] In this way, when forming the shape restoration part 120 on the link seal body 110, not only can the restoring force of the first and second elastic parts 114, 115 be improved, but also the wear of the first and second elastic parts 114, 115 and the support part 112 can be prevented, and the service life of the link seal 100 can be extended.

[0039] The operation of the endless track link seal of the present invention according to FIGS. 1 to 7 above will be described.

[0040] First, when an impact force is applied axially to the bush 4, the link seal 100 compresses and expands. When the impact force is transmitted axially to the bush 4 and the link seal 100 is compressed together, an expansion force is generated by the repulsive force of the shape restoration part 120 itself to return the close contact space part 113 side of the link seal body 110 to its original position. Next, when the bush 4 moves backward, the expansion force of the shape restoration part 120 is transmitted to the link seal body 110, and the restoring force for the link seal 100 to return to its original position can be maximized.

[0041] Even if such an operation is repeated, there is an effect that the reduction of the restoring force of the link seal 100 by the shape restoration part 120 can be suppressed as much as possible. In this way, wear such as uneven wear of the link seal 100 can be reduced, leakage of lubricating oil can be prevented, inflow of foreign substances from the outside can be blocked, and the life can be further extended.

[0042] The above description merely exemplarily explains the technical idea of the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains should be able to make various modifications and deformations without departing from the essential characteristics of the present invention. Therefore, the protection scope of the present invention should be interpreted by the scope of the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the rights of the present invention.

Description of Reference Numerals

[0043] 100 Link seal 110 Link seal body 111 Insertion hole 112 Support part 113 Close contact space part 114 First elastic part 115 Second elastic part 116 Forming groove 120 Shape restoration part

Claims

1. A link seal body (110) that has a donut shape, with an insertion hole (111) drilled in the center of the inner side, a support portion (112) protruding from the center on the outer side, and first and second elastic portions (114) and (115) protruding so as to be separated with an adhering space portion (113) having a predetermined space on both sides of the support portion (112); A shape restoration portion (120) integrally formed with the link seal body (110) to double the restoring force of the link seal body (110); Comprising; At the inner end of the adhering space portion (113) of the link seal body (110), a forming groove (116) having a support claw (116a) whose inlet is narrower than the maximum width in the forming groove (116) is formed so as to prevent the separation of the shape restoration portion (120); The shape restoration portion (120) is double-injected with ethylene propylene diene monomer (EPDM), a second synthetic resin material, into the forming groove (116) of the link seal body (110) and integrally joined. A link seal for an endless track, characterized in that

2. In a method for manufacturing a link seal for an endless track, A first step of forming a link seal body (110) using a first synthetic resin material, which has a donut shape, with an insertion hole (111) drilled in the center of the inner side, a support portion (112) protruding from the center on the outer side, and first and second elastic portions (114) and (115) protruding so as to be separated with an adhering space portion (113) having a predetermined space on both sides of the support portion (112); A second step of double-injecting ethylene propylene diene monomer (EPDM), which is a second synthetic resin material, into a part of the link seal body (110) to form a shape restoration portion (120); Including; In the first step, the link seal body (110) is formed with the forming groove (116) having a support claw (116a) whose inlet is narrower than the maximum width in the forming groove (116) at the inner end of the adhering space portion (113) so as to prevent the separation of the shape restoration portion (120). A method for manufacturing a link seal for an endless track, characterized in that

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