Oil cylinder with anti-loosening and anti-seepage oil cylinder cover

Abstract

The invention discloses an oil cylinder with an anti-loosening and anti-seepage cylinder cover, comprising a cylinder barrel and a piston rod slidably connected in the cylinder barrel, the end of the cylinder barrel is fixedly connected with the cylinder cover, the cylinder cover is provided with a cylinder cover connecting tube at one end close to the cylinder barrel, the outer wall of the cylinder cover connecting tube is fixedly connected to the inner wall of the cylinder barrel; the end of the cylinder barrel close to the cylinder cover is provided with a connecting boss, the cylinder cover is provided with a cylinder cover ring groove arranged corresponding to the connecting boss, the connecting boss is inserted into the cylinder cover ring groove, the barrel mouth of the cylinder barrel of the present application is inserted into the cylinder cover ring groove of the cylinder cover, so that the cylinder cover generates a uniform centripetal pressure on the barrel mouth of the cylinder barrel; even if the door frame is elastically deformed after load, so that the oil cylinder is subjected to a large lateral force, the barrel mouth will not be deformed, and only the cylinder barrel as a whole will have a tendency of lateral movement, thereby avoiding the occurrence of oil leakage caused by the deformation of the barrel mouth of the cylinder barrel due to lateral force, thereby improving its safety and reliability.

Description

Technical Field

[0001] The invention relates to the technical field of oil cylinders, in particular to an oil cylinder with an anti-loosening and anti-seepage oil cylinder cover. Background Art

[0002] At present, most of the hydraulic cylinders used in the lifting systems of the forklift industry are piston cylinders, and some are plunger cylinders. The effective working area of ​​the piston cylinder is the inner diameter of the cylinder barrel, and the rod diameter of the piston is smaller, so the wall thickness of the cylinder head can be designed to be thicker. After removing the space for the second sealing ring or guide belt, the remaining space can meet the requirements of the sealing ring groove. Therefore, the seal is placed where the cylinder barrel wall thickness is the thickest and far away from the barrel mouth. For scenes with high stability of the long-stroke pressure rod, it is necessary to increase the rod diameter and reduce the gap between the piston rod and the cylinder barrel. For example, the plunger cylinder is relatively typical. The minimum wall thickness of the cylinder head support part is only 2.5mm, so there is no way to arrange the seal in the support part. Therefore, most of the seals are moved to the front of the cylinder head (guide sleeve) thread, at the barrel mouth of the cylinder.

[0003] Since the inner diameter of the cylinder where the sealing ring is arranged must be larger than the bottom diameter of the cylinder thread, the cylinder wall at the mouth of the cylinder is very thin, generally only a few millimeters, and the cylinder wall thickness cannot be increased. Increasing the wall thickness will increase the installation space of the cylinder and increase the cost. It is difficult to purchase non-standard wall thickness. With the existing wall thickness, moving the seal to the mouth of the cylinder will cause two quality risks:

[0004] 1. When the mast is under heavy load and high position, the oil cylinder will deform forward with the mast. At this time, the cylinder head needs to bear a large lateral force, causing the cylinder mouth to deform into an elliptical shape. Through finite element simulation, the maximum deformation exceeds 0.1mm, which is close to the critical compression of the seal. In actual use, oil leakage often occurs at the joint between the cylinder head and the cylinder end face. Secondly, under the action of alternating deformation, the threaded connection between the cylinder head and the cylinder is also prone to loosening.

[0005] 2. If in actual use, the piston cylinder accumulates oil in the upper chamber due to internal leakage, or it is a plunger cylinder and the upper and lower chamber channels are blocked, when the unloaded mast is raised to the highest position (that is, the piston is close to the cylinder head limit), the upper chamber will instantly generate an impact pressure of several tens of MPa, which will cause the barrel mouth to expand and deform. At the very least, it will cause the seal to leak due to insufficient compression. At worst, the deformation is too large, which will cause the connection between the cylinder head and the cylinder barrel to loosen, and even cause the cylinder head to fall off under the impact of high oil pressure. Summary of the invention

[0006] The object of the present invention is to provide an oil cylinder with an anti-loosening and anti-seepage oil cylinder cover to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An oil cylinder with an anti-loosening and anti-seepage oil cylinder cover, comprising a cylinder barrel and a piston rod slidably connected to the cylinder barrel, the end of the cylinder barrel is fixedly connected to the cylinder cover, the piston rod passes through the cylinder cover, the cylinder cover is provided with a cylinder cover connecting tube at one end close to the cylinder barrel, the cylinder cover connecting tube is inserted into the cylinder barrel, and the outer wall of the cylinder cover connecting tube is fixedly connected to the inner wall of the cylinder barrel;

[0009] The end of the cylinder barrel close to the cylinder head is provided with a connecting boss, and the cylinder head is provided with a cylinder head ring groove arranged corresponding to the connecting boss, and the connecting boss is inserted into the cylinder head ring groove.

[0010] As a further solution of the present invention: the thickness of the connecting boss gradually decreases from the end away from the cylinder head to the end close to the cylinder head to form a boss slope, and the cylinder head ring groove is provided with a ring groove slope arranged in coordination with the boss slope.

[0011] As a further solution of the present invention: the boss inclined surface is an annular structure, and the boss inclined surface is pressed against the inner side of the annular groove inclined surface.

[0012] As a further solution of the present invention: a dust ring is provided between the cylinder cover and the piston rod, and the dust ring is located at one end of the cylinder cover away from the cylinder barrel.

[0013] As a further solution of the present invention: a first sealing ring is provided between the cylinder cover and the piston rod, the first sealing ring is located at one end of the cylinder cover away from the cylinder barrel, and the dust ring is located on the outside of the first sealing ring.

[0014] As a further solution of the present invention: a steel back bearing is provided between the inner side of the cylinder head connecting tube and the piston rod.

[0015] As a further solution of the present invention: the outer wall of the cylinder head connecting tube is provided with an external thread, the inner wall of the cylinder barrel is provided with an internal thread, and the cylinder head connecting tube is threadedly connected to the cylinder barrel.

[0016] As a further solution of the present invention: a second sealing ring is provided between the cylinder head connecting tube and the cylinder tube, and the second sealing ring is located close to the cylinder head ring groove.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present application provides a cylinder head ring groove on the cylinder head and a connecting boss on the cylinder barrel. Since the barrel mouth of the cylinder barrel is inserted into the cylinder head ring groove of the cylinder head, when the cylinder head has a tendency to move sideways, the cylinder head will generate a uniform lateral pressure on the barrel mouth of the cylinder barrel, thereby not causing the barrel mouth of the cylinder barrel to deform, but only causing the cylinder barrel as a whole to move sideways, thereby avoiding the problem of the barrel mouth of the cylinder barrel being deformed. Since the barrel mouth will not be deformed, the barrel mouth seal will not fail, thereby improving the safety performance;

[0019] 2. The present application provides a cylinder head ring groove and a connecting boss with a slope structure, and the connecting boss is inserted into the cylinder head ring groove, so that the cylinder head forms a large tightening force on the barrel mouth of the cylinder barrel in the center line direction, which can effectively prevent the barrel mouth from expanding and deforming. At the same time, under the action of the tightening force, the thread gap between the cylinder head and the cylinder barrel will be compressed, the friction force of the thread pair will be increased, and the connection strength of the thread will be further improved to prevent the cylinder head from falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of this embodiment;

[0021] Figure 2 It is a schematic diagram of the local structure of this embodiment.

[0022] In the figure: 1-piston rod, 2-cylinder head, 21-cylinder head ring groove, 22-ring groove inclined surface, 23-cylinder head connecting tube, 3-second sealing ring, 4-steel back bearing, 5-cylinder barrel, 51-connecting boss, 52-boss inclined surface, 6-threaded connection pair, 7-dust ring, 8-first sealing ring. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1-2In the embodiment of the present invention, an oil cylinder with an anti-loosening and anti-seepage oil cylinder cover comprises a cylinder barrel 5 and a piston rod 1 slidably connected to the cylinder barrel 5. A piston is provided at the lower end of the piston rod 1. The piston slides up and down in the cylinder barrel 5, thereby driving the piston rod 1 to slide relative to the cylinder barrel 5. A cylinder cover 2 is fixedly connected to the end of the cylinder barrel 5. The piston rod 1 passes through the cylinder cover 2. A first sealing ring 8 is provided between the cylinder cover 2 and the piston rod 1. The first sealing ring 8 is located at one end of the cylinder cover 2 away from the cylinder barrel 5. A dust ring 7 is provided between the cylinder cover 2 and the piston rod 1. The dust ring 7 is located at one end of the cylinder cover 2 away from the cylinder barrel 5, that is, the dust ring 7 is located at the barrel mouth of the cylinder barrel 5. The first sealing ring 8 is located on the inner side of the dust ring 7. The dust ring 7 is used to prevent dust from entering the cylinder cover 2. The first sealing ring 8 is used to ensure the sealing performance between the outer end of the cylinder cover 2 and the piston rod 1. A cylinder head connecting tube 23 is provided at one end of the cylinder head 2 close to the inner side of the cylinder barrel 5. The cylinder head connecting tube 23 is inserted into the cylinder barrel 5. The outer wall of the cylinder head connecting tube 23 is fixedly connected to the inner wall of the cylinder barrel 5. The outer wall of the cylinder head connecting tube 23 is provided with an external thread, and the inner wall of the cylinder barrel 5 is provided with an internal thread. The external thread of the cylinder head connecting tube 23 is connected with the internal thread of the cylinder barrel 5 to form a threaded connection pair 6. A second sealing ring 3 is provided between the cylinder head connecting tube 23 and the cylinder barrel 5. The second sealing ring 3 is located at the position of the barrel mouth of the cylinder barrel 5, that is, the second sealing ring 3 is located on the outside of the threaded connection pair 6. A steel back bearing 4 is provided between the inner side of the cylinder head connecting tube 23 and the piston rod 1.

[0025] A connecting boss 51 is provided at the end of the cylinder barrel 5 close to the cylinder head 2. The cylinder head 2 is provided with a cylinder head ring groove 21 arranged corresponding to the connecting boss 51. The thickness of the connecting boss 51 gradually decreases from the end away from the cylinder head 2 to the end close to the cylinder head 2 to form a boss inclined surface 52. The cylinder head ring groove 21 is provided with a ring groove inclined surface 22 arranged in coordination with the boss inclined surface 52. The connecting boss 51 is inserted into the cylinder head ring groove 21. The boss inclined surface 52 is an annular structure, so that the connecting boss 51 forms a conical structure with a conical surface. The platform bevel 52 is crimped to the inner side of the annular groove bevel 22, so when the cylinder head 2 is connected to the cylinder barrel 5, the connecting boss 51 is screwed into the cylinder head annular groove 21 on the cylinder head 2, and the conical surface of the connecting boss 51 gradually penetrates into the cylinder head annular groove 21 as the cylinder head 2 and the cylinder barrel 5 are connected, and at the same time, the conical surface of the connecting boss 51 and the annular groove bevel 22 are squeezed and meshed with each other. The deeper the cylinder head 2 is screwed in, the tighter the meshing is, and a large tightening force in the centerline direction can be formed on the barrel mouth of the cylinder barrel 5 through the cylinder head 2.

[0026] When the present invention is in use, when the forklift mast is in a high position with a heavy load, most of the piston rod 1 of the oil cylinder is in an extended state. Due to the load, the forklift mast will produce elastic deformation forward, thereby generating a large lateral force on the piston rod 1 of the oil cylinder. Under the action of the lateral force, the piston rod 1 will have a tendency to move sideways, thereby generating a large extrusion pressure on one side of the cylinder head 2. In the traditional connection between the cylinder barrel 5 and the cylinder head 2, the cylinder head 2 will only transmit an extrusion pressure to one side of the cylinder barrel 5, which may cause the barrel mouth to undergo an elliptical deformation. In the present embodiment, since the barrel mouth of the cylinder barrel 5 is plugged into the cylinder head ring groove 21 of the cylinder head 2, when the cylinder head 2 has a tendency to move sideways, the cylinder head will generate a uniform centripetal pressure on the barrel mouth of the cylinder barrel 5, thereby not causing the barrel mouth of the cylinder barrel 5 to deform, but only causing the cylinder barrel 5 as a whole to have a tendency to move sideways, thereby avoiding the problem of deformation of the barrel mouth of the cylinder barrel 5. Since the barrel mouth will not deform, the barrel mouth seal will not fail, thereby improving safety performance.

[0027] When the oil cylinder is used for a long time, the piston rod may accumulate oil in the upper chamber of the oil cylinder due to internal leakage, or the upper and lower chamber channels of the plunger pump may be blocked. When the unloaded gantry is raised to the highest position, that is, the piston is close to the limit position of the cylinder head 2, the upper chamber of the oil cylinder will instantly generate a pressure of tens of MPa. This pressure will impact the inner wall of the cylinder head 2 and the cylinder barrel 5. In the radial direction, the mouth of the cylinder barrel 5 will be subjected to a large radial impact force, which may cause expansion deformation of the mouth of the cylinder. Since the cylinder head 2 and the cylinder barrel 5 are connected by threads, When the mouth of the cylinder barrel 5 undergoes expansion deformation, the connection between the cylinder head 2 and the cylinder barrel 5 becomes loose. Under the axial impact of the oil pressure, the cylinder head 2 is easy to fall off. However, in the present embodiment, the mouth of the cylinder barrel 5 is inserted into the cylinder sleeve, so the cylinder head 2 can form a large tightening force in the center line direction on the mouth of the cylinder barrel 5, which can effectively prevent the mouth from expanding and deforming. Moreover, under the action of the tightening force, the thread gap between the cylinder head 2 and the cylinder barrel 5 will be compressed, thereby increasing the friction of the thread pair, further increasing the connection strength and preventing the cylinder head from falling off.

[0028] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0029] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An oil cylinder with an anti-loosening and anti-seepage oil cylinder cover, comprising a cylinder barrel (5) and a piston rod (1) slidably connected to the cylinder barrel (5), the end of the cylinder barrel (5) is fixedly connected to a cylinder cover (2), and the piston rod (1) passes through the cylinder cover (2), characterized in that: A cylinder head connecting tube (23) is provided at one end of the cylinder head (2) close to the cylinder barrel (5), the cylinder head connecting tube (23) is inserted into the cylinder barrel (5), and the outer wall of the cylinder head connecting tube (23) is fixedly connected to the inner wall of the cylinder barrel (5); The cylinder barrel (5) is provided with a connecting boss (51) at the end close to the cylinder head (2); the cylinder head (2) is provided with a cylinder head ring groove (21) arranged corresponding to the connecting boss (51); the connecting boss (51) is inserted into the cylinder head ring groove (21); the thickness of the connecting boss (51) gradually decreases from the end away from the cylinder head (2) to the end close to the cylinder head (2) to form a boss inclined surface (52); the cylinder head ring groove (21) is provided with an annular groove inclined surface (22) arranged in coordination with the boss inclined surface (52); the boss inclined surface (52) is an annular structure; the boss inclined surface (52) is pressed against the inner side of the annular groove inclined surface (22).

2. The oil cylinder with an anti-loosening and anti-seepage oil cylinder cover according to claim 1, characterized in that: A dustproof ring (7) is provided between the cylinder cover (2) and the piston rod (1), and the dustproof ring (7) is located at one end of the cylinder cover (2) away from the cylinder barrel (5).

3. The oil cylinder with an anti-loosening and anti-seepage oil cylinder cover according to claim 2, characterized in that: A first sealing ring (8) is provided between the cylinder cover (2) and the piston rod (1); the first sealing ring (8) is located at one end of the cylinder cover (2) away from the cylinder barrel (5); and the dust ring (7) is located outside the first sealing ring (8).

4. The oil cylinder with an anti-loosening and anti-seepage oil cylinder cover according to claim 1, characterized in that: A steel back bearing (4) is provided between the inner side of the cylinder head connecting tube (23) and the piston rod (1).

5. The oil cylinder with an anti-loosening and anti-seepage oil cylinder cover according to claim 1, characterized in that: The outer wall of the cylinder head connecting tube (23) is provided with an external thread, the inner wall of the cylinder barrel (5) is provided with an internal thread, and the cylinder head connecting tube (23) is threadedly connected to the cylinder barrel (5).

6. The oil cylinder with an anti-loosening and anti-seepage oil cylinder cover according to claim 1, characterized in that: A second sealing ring (3) is provided between the cylinder head connecting tube (23) and the cylinder tube (5), and the second sealing ring (3) is located close to the cylinder head ring groove (21).

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