Limiting structure of hydraulic jack

Abstract

According to the limiting structure of the hydraulic jack, the hydraulic jack comprises an oil cylinder, an outer sleeve and a piston rod, the oil cylinder is arranged in the outer sleeve, an oil storage cavity is formed between the outer wall of the oil cylinder and the inner wall of the outer sleeve, the piston rod is arranged in the oil cylinder in an up-down moving mode, and the limiting structure comprises a sealing piece. The piston rod is sleeved with the sealing piece, the sealing piece is matched with the inner wall of the oil cylinder 1 in a sealing mode, an oil return hole is formed in the inner wall of the upper end of the oil cylinder 1, and a limiting groove is formed in the position, corresponding to the position where the piston rod reaches the maximum jacking stroke, of the inner wall of the oil cylinder. A limiting hole communicated with the oil cylinder inner cavity and the oil storage cavity is formed in the limiting groove. The vertical oil jack has the advantages that pressure borne by the periphery of the oil return hole can be dispersed, a sealing piece is not prone to being damaged, the service life of the vertical oil jack is prolonged, and the purpose that the jack is safe and reliable to use is achieved.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic jack technology, specifically relating to a limiting structure for a hydraulic jack. Background Technology

[0002] Hydraulic jacks are mainly used in transportation, factories, and mines for vehicle repair and other lifting operations. When bearing loads, hydraulic jacks require a limiting structure to control their maximum stroke and prevent damage. Traditional vertical hydraulic jacks rely on limiting holes in the cylinder wall, along with seals, for this limiting function. When the jack rises to a certain height, causing the seal to reach the limiting hole, the hydraulic fluid returns through the hole to the inner casing, stopping the jack from rising further. However, this type of limiting structure results in relatively high pressure around the limiting hole, which can easily damage the seal, leading to high seal maintenance costs and affecting the jack's lifespan.

[0003] Specifically, the commonly used limiting structures currently include the following types:

[0004] The first type is as follows Figure 1 As shown, a limiting hole 11 is opened at the upper end of the oil cylinder 1. When the cup-shaped pad 4 passes through the limiting hole 11, the oil returns to the inside of the outer sleeve 2 through the limiting hole 11. The limitation structure of this cup-shaped pad 4 and the limiting hole 11 has the disadvantage that the limiting ability is generally poor.

[0005] The second type is as follows Figure 2 As shown, a groove 12 and an oil return hole 13 are provided at the upper end of the cylinder 1. When the Y-shaped sealing ring used as the sealing element 5 passes through the groove 12, the oil enters between the cylinder 1 and the piston rod 3 through the groove 12, and then returns to the inside of the outer sleeve 2 through the oil return hole 13. The limitation structure of this Y-shaped sealing ring and groove 12 is not suitable for products with low stroke.

[0006] The third type is as follows Figure 3 As shown, a limiting hole 11 is opened at the upper end of the cylinder 1. When the Y-shaped sealing ring used as the sealing element 5 passes through the limiting hole 11, the oil returns to the inside of the outer sleeve 2 through the limiting hole 11. Although the limiting ability of this kind of limiting structure with Y-shaped sealing ring and limiting hole 11 is improved to a certain extent compared with the previous two technologies, it still cannot meet the requirements of ultra-high number of operations.

[0007] In view of the above-mentioned existing technology, it is necessary to improve the limiting structure of the existing vertical hydraulic jack. To this end, the applicant has made a useful design, and the technical solution to be introduced below is produced in this context. Utility Model Content

[0008] The utility model discloses a hydraulic jack's limiting structure can effectively reduce the abrasion of sealing element, make the service life of vertical hydraulic jack prolong.

[0009] The utility model discloses a hydraulic jack's limiting structure can effectively reduce the abrasion of sealing element, make the service life of vertical hydraulic jack prolong.

[0010] In one embodiment of the utility model, it further includes a back support ring, which is matched with the sealing element above and is sleeved on the piston rod with the sealing element.

[0011] In another embodiment of the utility model, the sealing element has a step on the upper end, and the back support ring is matched with the step and is matched with the inner wall of the oil cylinder.

[0012] In another embodiment of the utility model, the sealing element is a Y-shaped sealing ring.

[0013] In another embodiment of the utility model, the limiting hole is arranged on the bottom of the annular limiting groove in the height direction.

[0014] In another embodiment of the utility model, the depth of the annular limiting groove is 0.2-0.8mm.

[0015] In another embodiment of the utility model, the upper end and the lower end of the annular limiting groove are respectively formed as inclined surfaces.

[0016] In another embodiment of the utility model, the height of the piston head of the piston rod is greater than the height of the annular limiting groove.

[0017] The utility model discloses a ring -shaped limit groove is set up in the oil cylinder inner wall of hydraulic jack, and is equipped with the limit hole on ring -shaped limit groove, and when reaching the maximum jacking stroke, the sealing element passes through ring -shaped limit groove, and the oil enters the oil storage cavity in the outer sleeve through the limit hole, so that the vertical hydraulic jack does not lift again, plays the limiting effect, and the structure can disperse the pressure around the limit hole, and the sealing element is not easy to damage, prolongs the service life of vertical oil pressure jack, and reaches the safe and reliable purpose of jack use. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is structural schematic diagram of one limit structure in prior art;

[0019] Figure 2 It is structural schematic diagram of another limit structure in prior art;

[0020] Figure 3 It is structural schematic diagram of still another limit structure in prior art;

[0021] Figure 4 It is structural schematic diagram of one embodiment of the utility model;

[0022] Figure 5 It is Figure 4 Structural schematic diagram of A part in it.

[0023] In the drawing: 1. oil cylinder, 11. limit hole, 12. pull groove, 13. oil return hole, 14. ring -shaped limit groove;2. outer sleeve, 21. oil storage cavity;3. piston rod, 31. piston head;4. bowl -type pad;5. sealing element, 51. step;6. base;7. oil pump;8. back ring. DETAILED DESCRIPTION

[0024] The specific embodiments of the utility model are described in detail in the following combined with the drawings, but the description of embodiment is not the limitation of technical scheme, and any form but not essential change according to the concept of the utility model should be regarded as the protection scope of the utility model.

[0025] In the following description, the concepts of directionality (or directionality) of up, down, left, right, front and back are for the position state of the figure being described, and the purpose is to facilitate the public to understand, so it cannot be understood as the special limitation of the technical scheme provided by the utility model.

[0026] See Figure 4 The utility model relates to a kind of limit structure of hydraulic jack, the hydraulic jack includes oil cylinder 1, outer sleeve 2 and piston rod 3, the oil cylinder 1 and outer sleeve 2 are set on base 6, oil cylinder 1 is set in outer sleeve 2, and oil storage cavity 21 is formed between the outer wall of the oil cylinder 1 and the inner wall of outer sleeve 2, and the piston rod 3 is movably arranged in oil cylinder 1.

[0027] The limiting structure comprises a back-up ring 8 and a sealing member 5, the back-up ring 8 is matched with the sealing member 5 at the upper part of the sealing member 5 and is sleeved to the lower part of the piston rod 3 with the sealing member 5. The sealing member 5 is provided with a step 51 at the outer edge of the upper end, and the back-up ring 8 is limited and fixed by the step 51. The outer wall of the back-up ring 8 and the sealing member 5 is in sealing cooperation with the inner wall of the oil cylinder 1. In the embodiment, the sealing member 5 is a Y-shaped sealing ring, when the oil acts on the groove of the Y-shaped sealing ring, the wall of the Y-shaped sealing ring expands towards the inner wall of the oil cylinder 1, so that the ideal sealing contact between the Y-shaped sealing ring and the inner wall of the oil cylinder 1 is achieved, and the piston rod 3 will not fall during the process of lifting the load, so as to ensure the safety. Of course, the sealing member 5 is not limited to the Y-shaped sealing ring, and can be a bowl gasket or other ring-shaped sealing member.

[0028] Continue to see Figure 4 and in combination Figure 5 As the technical scheme provided by the utility model, the oil cylinder 1 is provided with an oil return hole 13 on the inner wall of the upper end, further, the oil cylinder 1 is provided with an annular limiting groove 14 around the inner wall and corresponding to the position where the piston rod 3 reaches the maximum lifting stroke. The annular limiting groove 14 is arranged around the inner wall of the oil cylinder 1, that is, in a ring shape; a limiting hole 11 is formed in the bottom position of the annular limiting groove 14 in the height direction. The oil return hole 13 and the limiting hole 11 are in communication with the inner cavity of the oil cylinder 1 and the oil storage cavity 21.

[0029] When the operator presses the oil pump 7 up and down, the oil in the oil cylinder 2 enters the bottom of the inner cavity of the oil cylinder 1 through the oil channel on the base 6, pushes the piston rod 3 to rise, and reaches the maximum lifting stroke. If the operator continues to operate the oil pump 7 at this time, the back-up ring 8 and the sealing member 5 at the lower part of the piston rod 3 pass through the annular limiting groove 14 as the piston rod 3 rises, at this time, the oil in the lower part of the inner cavity of the oil cylinder 1 enters the oil storage cavity 21 in the outer sleeve 2 through the limiting hole 11 in the annular limiting groove 14, so that the piston rod 3 does not rise any more, and plays a limiting role. In order to enable the back-up ring 8 and the sealing member 5 to pass through the annular limiting groove 14 smoothly, the upper edge and the lower edge of the annular limiting groove 14 are respectively formed into inclined surfaces. Further, the height H of the piston head 31 of the piston rod 3 is greater than the height h of the annular limiting groove 14.

[0030] The above limiting structure mentioned in the utility model can disperse the pressure around the oil return hole, is not easy to cause damage to the sealing member 5, is favorable for prolonging the service life of the low-pressure vertical hydraulic jack, and thus the purpose of the invention is achieved.

Claims

1. A hydraulic jack limiting structure, said jack comprising a cylinder (1), an outer sleeve (2) and a piston rod (3), said cylinder (1) being arranged in the outer sleeve (2), and an oil storage cavity (21) being formed between the outer wall of the cylinder (1) and the inner wall of the outer sleeve (2), said piston rod (3) being arranged in the cylinder (1) and moving up and down, said limiting structure comprising a sealing member (5), said sealing member (5) being sleeved on said piston rod (3) and sealingly cooperating with the inner wall of said cylinder (1), and said cylinder (1) being provided with an oil return hole (13) on the inner wall of the upper end, characterized in that: The oil cylinder (1) is provided with an annular limiting groove (14) on the inner wall and corresponding to the position where the piston rod (3) reaches the maximum lifting stroke, and the annular limiting groove (14) is provided with a limiting hole (11) communicating with the inner cavity of the oil cylinder (1) and the oil storage cavity (21). ​ 2. The hydraulic jack limiting structure according to claim 1, characterized in that: A back-up ring (8) is further included, which is matched with the sealing member (5) above the sealing member (5) and is sleeved on the piston rod (3) with the sealing member (5).

3. The hydraulic jack limiting structure according to claim 2, characterized in that: The sealing member (5) is provided with a step (51) on the outer edge of the upper end, and the back-up ring (8) is matched and installed with the step (51) and forms a sealing cooperation with the inner wall of the oil cylinder (1).

4. The hydraulic jack limiting structure according to claim 1, characterized in that: The sealing member (5) is a Y-shaped sealing ring.

5. The hydraulic jack limiting structure according to claim 1, wherein: The limiting hole (11) is provided on the bottom of the annular limiting groove (14) in the height direction.

6. The hydraulic jack limiting structure according to claim 1, wherein: The depth of the annular limiting groove (14) is 0.2-0.8mm.

7. The hydraulic jack limiting structure according to claim 1, wherein: The upper end and the lower end of the annular limiting groove (14) are respectively formed into inclined surfaces.

8. The hydraulic jack limiting structure according to claim 1, wherein: The height of the piston head (31) of the piston rod (3) is greater than the height of the annular limiting groove (14).

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