Piston structure for oil cylinder of large pile driving barge capable of accurately applying pre-tightening force

Abstract

The piston structure comprises a piston, a piston rod matched with the piston, a nut matched on the piston rod and a plurality of screws arranged on the nut, the center of the piston is a two-step-shaped through hole, the piston rod is matched in the piston through hole, and the screw is arranged on the nut. An external thread is arranged on the periphery of the piston rod, the nut is connected to the external thread of the piston rod in a threaded mode, a plurality of threaded holes penetrating to the inner end face of the nut are evenly formed in the outer end face of the nut in the circumferential direction at intervals, a plurality of screws are arranged in the threaded holes in a one-to-one correspondence and matched mode, and the screws abut against the step face of the piston through hole. According to the utility model, the purchase cost of large-scale equipment can be reduced; meanwhile, the labor cost and the time cost required for applying the torque are reduced; and a corresponding accurate torque value can be ensured to be applied.

Description

Technical Field

[0001] The utility model relates to the field of hydraulic technology, and more specifically to a piston structure for a large-scale pile-driving ship oil cylinder that can accurately apply pre-tightening force. Background Art

[0002] The piston structure of the oil cylinder of a large pile-driving ship is generally a large piston of a large oil cylinder. It is generally difficult to accurately apply preload force to the piston of a large oil cylinder. Most of the tightening is done by manpower or equipment. The main problem is that the specific torque value cannot be confirmed. Even if it is the same equipment, it is difficult to ensure that the torque applied each time is the same. When repairing the oil cylinder, there are often no large torque-applying equipment on the construction site. After disassembling or replacing the piston, the corresponding preload torque cannot be accurately applied on site. Generally, it is installed only by manpower, and the thread may be too tight or too loose. In addition, the application of piston thread preload has a great influence on the fatigue life of the thread. Excessive or too small preload force is not good for the service life of the thread. Therefore, it is crucial to accurately apply preload force to the piston of a large oil cylinder.

[0003] In the existing technical solutions, the piston connection is generally a threaded connection, such as Figure 1 At present, there are generally the following designs for applying preload to the piston:

[0004] 1. One end of the piston is milled into a hexagonal shape, such as Figure 2 As shown. After the piston is milled hexagonally, the torque can be accurately applied by a special torque wrench. However, this method is only suitable for pistons with smaller diameters due to the limitations of processing equipment and special tool sizes.

[0005] 2. Drill a threaded hole on the piston end face, such as Figure 3 As shown. For pistons with large diameters, threaded holes are usually drilled on the piston end faces, and torque is applied with the assistance of special equipment. However, the torque value applied in this way is uncontrollable, inaccurate, and often too small or too large.

[0006] Therefore, the current method of applying preload force to a large diameter piston in the prior art is time-consuming, labor-intensive, and costly, and the applied torque value is inaccurate. Utility Model Content

[0007] One purpose of the utility model is to provide a piston structure for a large pile-driving ship oil cylinder that accurately applies preload, which solves the problem that a large oil cylinder cannot accurately apply preload when installing the piston, and the problem that a large oil cylinder equipment maintenance site does not have a large torque application device, resulting in the inability to apply the corresponding preload. The torque tool of the present application can overlap with the torque tool of an ordinary screw, that is, a manual or pneumatic torque wrench can be used, which reduces the equipment purchase cost; at the same time, it reduces the labor and time cost required for torque application; and can also ensure that the corresponding accurate torque value is applied.

[0008] In order to solve the above technical problems, the utility model provides a piston structure for a large pile-driving ship cylinder that accurately applies a preload, comprising a piston, a piston rod that cooperates with the piston, a nut that cooperates with the piston rod, and a plurality of screws arranged on the nut, wherein the center of the piston is a two-stepped through hole, the piston rod cooperates in the piston through hole, the outer periphery of the piston rod is provided with an external thread, the nut is threadedly connected to the external thread of the piston rod, the outer end face of the nut is circumferentially evenly provided with a plurality of threaded holes that penetrate to the inner end face of the nut, and a plurality of screws are respectively arranged in the nut in a one-to-one corresponding manner, and the screws are tightly against the step surface of the piston through hole.

[0009] Preferably, it further comprises an annular washer which is sleeved on the outer periphery of the piston rod and located on the step surface of the piston through hole, and the screw is tightly pressed against the annular washer.

[0010] Preferably, the nut is located in the through hole of the piston, and the outer diameters of the nut and the annular washer are both smaller than the inner diameter of the piston.

[0011] Preferably, the outer ends of the plurality of screws are integrally provided with a tightening portion, the outer diameter of which is larger than the outer diameter of the screw.

[0012] Preferably, a hexagonal recessed hole is provided at the center of the outer end surface of the tightening portion.

[0013] The utility model at least has the following beneficial effects:

[0014] The present application discloses a piston structure design for a large pile-driving ship oil cylinder that accurately applies preload force. The design is characterized in that only a small torque tool is required to quickly, safely and accurately apply a large preload force, thereby reducing the difficulty of applying a large preload force and the cost of purchasing large torque-applying equipment. The torque-applying tool and the torque-applying tool for ordinary screws can be overlapped, that is, a manual or pneumatic torque wrench can be used, thereby avoiding the problem of no torque-applying equipment on site for piston replacement and requiring less labor and time costs.

[0015] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a general threaded connection of a piston in the background technology of the utility model;

[0017] Figure 2 This is a schematic diagram of a hexagonal milling on one end of a piston in the background technology of the utility model;

[0018] Figure 3This is a schematic diagram of a threaded hole on the piston end surface in the background technology of the utility model;

[0019] Figure 4 This is a schematic diagram of the installation of the piston structure of the utility model;

[0020] Figure 5 This is the explosion diagram of the piston structure of the utility model.

[0021] Explanation of the reference numerals: 1. piston, 2. piston rod, 3. nut, 4. annular washer, 5. screw, 6. tightening part, 7. threaded hole. DETAILED DESCRIPTION

[0022] In order to better understand the purpose, structure and function of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement it according to the description.

[0023] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0024] like Figure 4 and Figure 5 As shown, the utility model provides a piston structure for a large-scale pile-driving ship oil cylinder that accurately applies a preload, comprising a piston 1, a piston rod 2 matched with the piston 1, a nut 3 matched with the piston rod 2, and a plurality of screws 5 arranged on the nut 3, wherein the center of the piston 1 is a two-step-type through hole, the piston rod 2 is matched in the through hole of the piston 1, the outer periphery of the piston rod 2 is provided with an external thread, the nut 3 is threadedly connected to the external thread of the piston rod 2, the outer end surface of the nut 3 is circumferentially evenly provided with a plurality of threaded holes 7 penetrating to the inner end surface of the nut 3, wherein a plurality of screws 5 are respectively arranged in a one-to-one corresponding manner, and the screws 5 are tightly pressed against the step surface of the through hole of the piston 1.

[0025] The number and size of the screws 5 are determined according to the size of the thread connecting the piston 1 and the piston rod 2. Larger-sized threads require greater preload, so the size and number of the screws 5 required will also increase accordingly. The screws 5 are operated by a torque wrench, which has high precision and is generally a torque wrench with a digital display. A preset torque value is set for the torque wrench, and then the screws 5 are tightened to apply precise preload.

[0026] In another technical solution, an annular washer 4 is further included, which is sleeved on the outer periphery of the piston rod 2 and located on the step surface of the through hole of the piston 1. The screw 5 is tightly pressed against the annular washer 4, and the annular washer 4 is a steel washer.

[0027] In another technical solution, the nut 3 is located in the through hole of the piston 1 , and the outer diameters of the nut 3 and the annular gasket 4 are both smaller than the inner diameter of the piston 1 .

[0028] In another technical solution, the outer ends of the plurality of screws 5 are integrally provided with a tightening portion 6, whose outer diameter is larger than the outer diameter of the screw 5. A hexagon socket is provided at the center of the outer end surface of the tightening portion 6. The tightening portion 6 is used to facilitate the operation of a torque wrench, and the setting of the hexagon socket facilitates the connection of a torque wrench.

[0029] During assembly, first assemble the piston 1 and the piston rod 2 together, and install the annular gasket 4 inside the piston 1 on the step surface; secondly, connect multiple screws 5 with nuts 3, and then thread the nuts 3 onto the piston rod 2; then use a small torque wrench to apply the set precise torque to the screws 5 in turn, so as to apply precise preload force to the entire piston 1 structure.

[0030] It can be understood that the present invention is described by some embodiments, and those skilled in the art know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation mode. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, other modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the illustrations shown and described here.

Claims

1. A piston structure for a large pile-driving ship cylinder that accurately applies preload, characterized in that: It includes a piston, a piston rod matched with the piston, a nut matched with the piston rod and a plurality of screws arranged on the nut. The center of the piston is a two-step step-type through hole. The piston rod is matched in the piston through hole. The outer periphery of the piston rod is provided with an external thread. The nut is threadedly connected to the external thread of the piston rod. The outer end surface of the nut is circumferentially evenly provided with a plurality of threaded holes penetrating to the inner end surface of the nut, and a plurality of screws are respectively matched and arranged in the nut in a one-to-one manner. The screws are tightly against the step surface of the piston through hole.

2. The piston structure for a large pile-driving ship cylinder for accurately applying preload force according to claim 1, characterized in that: It also includes an annular washer, which is sleeved on the outer periphery of the piston rod and located on the step surface of the piston through hole, and the screw is tightly pressed against the annular washer.

3. The piston structure for a large pile-driving ship cylinder for accurately applying preload as claimed in claim 2, characterized in that: The nut is located in the piston through hole, and the outer diameters of the nut and the annular washer are both smaller than the inner diameter of the piston.

4. The piston structure for a large pile-driving ship cylinder for accurately applying preload force according to claim 1, characterized in that: The outer ends of the plurality of screws are all integrally provided with a tightening portion, the outer diameter of which is larger than the outer diameter of the screw.

5. The piston structure for a large pile-driving ship cylinder for accurately applying preload force as claimed in claim 4, characterized in that: A hexagonal recessed hole is arranged at the center of the outer end surface of the tightening part.

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