Forklift lifting oil cylinder shaft sealing mechanism

Abstract

The utility model discloses a forklift lifting oil cylinder shaft sealing mechanism. The forklift lifting oil cylinder is a single-action oil cylinder, and the shaft sealing mechanism (3) is arranged at the end of the rod side of the oil cylinder body (1). The shaft sealing mechanism comprises a guide sleeve (32) and a sliding bearing (31); the guide sleeve is installed at the end of the rod side of the oil cylinder body, the piston rod (2) is sleeved with the guide sleeve, the sliding bearing is assembled on the inner side of the guide sleeve, the piston rod is sleeved with the sliding bearing, and the piston rod and the guide sleeve are separated through the sliding bearing. A closed oil storage cavity is formed in the piston rod around the piston rod, and lubricating grease is injected into the oil storage cavity. According to the shaft sealing mechanism, the oil storage cavity is formed around the piston rod, the piston rod is always in contact with lubricating grease in the oil storage cavity, a lubricating oil film can be always kept on the surface of the piston rod, and therefore abrasion between the piston rod and the shaft sealing mechanism can be reduced.

Description

Technical Field

[0001] The utility model relates to a hydraulic equipment mechanism, in particular to a forklift lifting oil cylinder shaft sealing mechanism. Background Art

[0002] At present, the lifting cylinders of forklifts all use single-acting cylinders. The single-acting cylinder is a type of cylinder in the prior art, which generates a driving force through the pressure of liquid in a chamber to enable the device to push or pull. When the pressure oil enters a chamber of the hydraulic cylinder, it generates a thrust to push the piston rod forward. When a return stroke is required, the piston rod is pulled back to the initial position by external forces such as gravity or a spring.

[0003] One side of a single-acting cylinder is called the "rod side" and the other side is called the "piston side". The chamber on the rod side of a single-acting cylinder is called the rod chamber, and the chamber on the piston side of a single-acting cylinder is called the rodless chamber. The piston rod of a single-acting cylinder extends from the rod side of the cylinder body.

[0004] A shaft seal is provided at the rod side end of the cylinder body. The shaft seal and the piston rod are in closed sliding contact. On the one hand, it can guide the piston rod, and on the other hand, it can seal the rod cavity to prevent foreign matter from entering the rod cavity.

[0005] The current problem is:

[0006] There is no hydraulic oil in the rod chamber of the single-acting cylinder, so the piston rod surface cannot contact the hydraulic oil, and no oil film will be formed on the piston rod surface. When the single-acting cylinder is telescopic, there will be wear and tear because there is no lubricating oil film between the piston rod and the shaft seal, and the service life of both the piston rod and the shaft seal will be greatly reduced. Summary of the invention

[0007] The utility model aims to provide a shaft sealing mechanism for a lifting oil cylinder of a forklift, which can always keep a lubricating oil film on the surface of a piston rod.

[0008] In order to achieve the above technical purpose, the utility model adopts the following technical solutions:

[0009] A forklift lifting cylinder shaft sealing mechanism, the forklift lifting cylinder is a single-acting cylinder, the shaft sealing mechanism is arranged at the rod side end of the cylinder body; the shaft sealing mechanism includes a guide sleeve and a sliding bearing; the guide sleeve is installed at the rod side end of the cylinder body, the guide sleeve is sleeved on the piston rod, the sliding bearing is assembled on the inner side of the guide sleeve, the sliding bearing is sleeved on the piston rod, and the sliding bearing isolates the piston rod from the guide sleeve; a closed oil storage chamber is arranged around the piston rod in the piston rod, and the oil storage chamber is filled with lubricating grease.

[0010] Furthermore, the oil storage chamber has a specific structural form as follows: the shaft sealing mechanism also includes a dust ring; a dust ring embedding portion is arranged around the piston rod at the outer end portion of the guide sleeve, the dust ring is sleeved on the piston rod and embedded in the dust ring embedding portion, and an oil storage recess is arranged on the side of the dust ring facing the dust ring embedding portion, and the oil storage recess of the dust ring, the dust ring embedding portion and the piston rod together enclose the oil storage chamber.

[0011] Furthermore, the dust ring is a double-lip dust ring.

[0012] Furthermore, the dustproof ring is provided with a metal frame.

[0013] Furthermore, a lubrication enhancement gap is provided around the piston rod in the guide sleeve, and the lubrication enhancement gap is connected to the oil storage chamber.

[0014] Furthermore, the lubrication enhancement gap is specifically implemented in the form of a structure in which, under the isolation effect of the sliding bearing, a gap is retained between the piston rod and the guide sleeve at a portion of the guide sleeve close to the oil storage chamber, and the gap is connected to the oil storage chamber, thereby forming the lubrication enhancement gap.

[0015] Furthermore, the shaft sealing mechanism also includes a first sealing ring, which is arranged at the gap between the piston rod and the guide sleeve, and the first sealing ring closes the lubrication enhancement gap.

[0016] Furthermore, an oil filling cup and an overflow valve are provided on the piston rod, and the oil filling cup and the overflow valve are both connected to the oil storage chamber.

[0017] Compared with the prior art, the shaft sealing mechanism of the utility model has the following beneficial effects:

[0018] In the shaft sealing mechanism of the utility model, an oil storage chamber is arranged around the piston rod, and the piston rod always keeps in contact with the lubricating grease in the oil storage chamber, and the surface of the piston rod can always maintain a lubricating oil film, thereby reducing the wear between the piston rod and the shaft sealing mechanism. The service life of both the piston rod and the shaft sealing mechanism will be greatly extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The utility model is a schematic structural diagram of a forklift lifting cylinder shaft sealing mechanism. DETAILED DESCRIPTION

[0020] The utility model is further described below with specific embodiments:

[0021] This embodiment provides a forklift lifting cylinder shaft sealing mechanism, which is arranged at the rod side end of the cylinder body 1. In addition to realizing basic functions (see background technology introduction), the shaft sealing mechanism can also keep a lubricating oil film on the surface of the piston rod at all times.

[0022] See also Figure 1 The shaft sealing mechanism of this embodiment includes a sliding bearing 31, a guide sleeve 32, a first sealing ring 33, a second sealing ring 34, a dust ring 35, an oil filling cup 37 and a relief valve 38.

[0023] At the rod side end of the cylinder body 1 , the guide sleeve 32 is installed at the rod side end of the cylinder body 1 by means of bolt fasteners, and the guide sleeve 32 is sleeved on the piston rod 2 of the cylinder, or in other words, the piston rod 2 passes through the guide sleeve 32 .

[0024] A sliding bearing 31 is provided between the guide sleeve 32 and the piston rod 2. The sliding bearing 31 is assembled on the inner side of the guide sleeve 32 and is sleeved on the piston rod 2. The sliding bearing 31 separates the piston rod 2 from the guide sleeve 32 and partially separates the piston rod 2 from the guide sleeve 32, so that the piston rod 2 does not directly contact the guide sleeve 32. At the part not separated by the sliding bearing 31, a certain gap is retained between the piston rod 2 and the guide sleeve 32 (as indicated by the arrow B in the figure).

[0025] It should be noted that the partitioned portion is located at the portion of the guide sleeve 32 close to the piston, and the unpartitioned portion, that is, a certain gap portion is retained between the piston rod 2 and the guide sleeve 32, which is located at the portion of the guide sleeve 32 far away from the piston.

[0026] The piston rod 2 performs a telescopic movement at the rod-side end of the cylinder body 1 based on the sliding bearing 31. During the telescopic movement, the piston rod 2 and the sliding bearing 31 are in sliding contact, while the piston rod 2 and the guide sleeve 32 remain in a non-contact state.

[0027] A first sealing ring 33 is provided between the piston rod 2 and the guide sleeve 32. The first sealing ring 33 is provided at the unblocked position mentioned above, and the first sealing ring 33 plays the role of closing the gap. A second sealing ring 34 is provided between the guide sleeve 32 and the oil cylinder body 1. Under the sealing effect of the first sealing ring 33 and the second sealing ring 34, the rod side end of the oil cylinder body 1 is completely sealed.

[0028] The following are important innovations of the shaft sealing mechanism 3 of the present embodiment.

[0029] In order to accurately describe the technical solution, the following definitions are made in this implementation:

[0030] The end of the guide sleeve 32 away from the piston is called the outer end of the guide sleeve 32;

[0031] The end of the guide sleeve 32 close to the piston is referred to as the inner end of the guide sleeve 32 .

[0032] An annular recess is provided around the piston rod 2 at the outer end of the guide sleeve 32, and the annular recess is used to embed and assemble the dust ring 35. Therefore, the annular recess is called a dust ring embedding portion. The dust ring 35 is sleeved on the piston rod 2 and embedded in the dust ring embedding portion, thereby achieving a closed dustproof effect.

[0033] Importantly,

[0034] An annular depression is provided on one side of the dust ring 35 facing the dust ring embedding portion, and the annular depression is called an "oil storage depression" (as indicated by arrow A in the figure). When the dust ring 35 is assembled in the dust ring embedding portion, the oil storage depression of the dust ring 35, the dust ring embedding portion and the piston rod 2 together enclose a closed annular space around the piston rod 2 (as indicated by arrow A in the figure). For the convenience of description, the annular space is called an "oil storage chamber".

[0035] The oil filling cup 37 and the overflow valve 38 are arranged for the oil storage chamber.

[0036] Specifically,

[0037] The oil filling cup 37 and the relief valve 38 are both arranged on the guide sleeve 32 and are arranged near the oil storage chamber, and both are connected to the oil storage chamber through the pipeline channel inside the guide sleeve 32. In this way, lubricating grease can be injected into the oil storage chamber through the oil filling cup 37, and the relief valve 38 can discharge the excessive lubricating grease injected into the oil storage chamber.

[0038] In the oil storage chamber, the piston rod 2 always keeps in contact with the lubricating grease. During the extension and retraction process of the piston rod 2, the surface of the piston rod 2 can maintain an oil film with the help of the lubricating grease in the oil storage chamber, and the contact between the piston rod 2 and other components will have a lubricating effect, thereby reducing the situation of "sliding contact between the piston rod 2 and other components causing mutual wear".

[0039] In addition, the oil storage chamber is also connected to the previously mentioned "gap between the piston rod 2 and the guide sleeve 32 not separated by the sliding bearing 31" (as indicated by the arrow B in the figure), so that the lubricating grease injected into the oil storage chamber by the oil filling cup 37 also enters the gap. The most direct benefit of this arrangement is that the contact area between the lubricating grease and the piston rod 2 is greatly increased, which is more conducive to maintaining an oil film on the surface of the piston rod 2.

[0040] The gap between the piston rod 2 and the guide sleeve 32 that is not separated by the sliding bearing 31 actually plays a role in enhancing the lubrication effect. Therefore, this gap can be called a "lubrication enhancement gap" (as indicated by the arrow B in the figure).

[0041] In summary, the lubrication enhancement gap is arranged around the piston rod 2, and the lubrication enhancement gap is communicated with the oil storage chamber.

[0042] It should be noted that the dustproof ring 35 of the present embodiment is a metal frame dustproof ring, that is, the dustproof ring 35 is provided with a metal frame 351 , or in other words, the dustproof ring 35 is based on the metal frame 351 .

[0043] It should be noted that the dust ring 35 is a double-lip dust ring, which has a better dustproof sealing effect than the ordinary dust ring 35.

[0044] In the shaft sealing mechanism of this embodiment, the oil storage recess of the dust ring, the dust ring embedded part of the guide sleeve and the piston rod together form an oil storage chamber surrounding the piston rod. This arrangement allows the piston rod to always remain in contact with the lubricating grease, and the surface of the piston rod can always maintain a lubricating oil film, thereby reducing the wear between the piston rod and the shaft sealing mechanism. The service life of both the piston rod and the shaft sealing mechanism will be greatly extended.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A shaft sealing mechanism for a forklift lifting cylinder, wherein the forklift lifting cylinder is a single-acting cylinder, and the shaft sealing mechanism (3) is arranged at the rod-side end of the cylinder body (1); Features: The shaft sealing mechanism (3) comprises a guide sleeve (32) and a sliding bearing (31); The guide sleeve (32) is mounted on the rod-side end of the oil cylinder body (1), and the guide sleeve (32) is sleeved on the piston rod (2). The sliding bearing (31) is assembled on the inner side of the guide sleeve (32), the sliding bearing (31) is sleeved on the piston rod (2), and the sliding bearing (31) separates the piston rod (2) from the guide sleeve (32); A closed oil storage chamber is arranged inside the piston rod (2) and around the piston rod (2), and lubricating grease is filled in the oil storage chamber.

2. The forklift lifting cylinder shaft sealing mechanism according to claim 1, characterized in that: The oil storage chamber is specifically implemented in the following structural form: The shaft sealing mechanism (3) also includes a dust ring (35); a dust ring embedding portion is arranged around the piston rod (2) at the outer end of the guide sleeve (32); the dust ring (35) is sleeved on the piston rod (2) and embedded in the dust ring embedding portion; an oil storage recess is arranged on the side of the dust ring (35) facing the dust ring embedding portion; the oil storage recess of the dust ring (35), the dust ring embedding portion and the piston rod (2) together enclose the oil storage chamber.

3. The forklift lifting cylinder shaft sealing mechanism according to claim 2, characterized in that: The dustproof ring (35) is a double-lip dustproof ring.

4. The forklift lifting cylinder shaft sealing mechanism according to claim 2, characterized in that: The dustproof ring (35) is provided with a metal frame (351).

5. The forklift lifting cylinder shaft sealing mechanism according to claim 1, characterized in that: A lubrication enhancement gap is arranged around the piston rod (2) in the guide sleeve (32), and the lubrication enhancement gap is connected to the oil storage chamber.

6. The forklift lifting cylinder shaft sealing mechanism according to claim 5, characterized in that: The lubrication enhancement gap is specifically implemented in the following structural form: Under the isolation effect of the sliding bearing (31), a gap is retained between the piston rod (2) and the guide sleeve (32) at a portion of the guide sleeve (32) close to the oil storage chamber, and the gap is connected to the oil storage chamber, thereby forming the lubrication enhancement gap.

7. The forklift lifting cylinder shaft sealing mechanism according to claim 6, characterized in that: The shaft sealing mechanism (3) also includes a first sealing ring (33), which is arranged at the gap between the piston rod (2) and the guide sleeve (32), and the first sealing ring (33) closes the lubrication enhancement gap.

8. The forklift lifting cylinder shaft sealing mechanism according to claim 1, characterized in that: The piston rod (2) is provided with an oil filling cup (37) and an overflow valve (38), and the oil filling cup (37) and the overflow valve (38) are both connected to the oil storage chamber.

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