Double-deep-hole piston rod sealed by ball expansion type high-pressure plug

Abstract

The utility model provides a double-deep-hole piston rod sealed by a ball expansion type high-pressure plug. The double-deep-hole piston rod comprises a rod body, a rodless cavity liquid passing deep hole, a rod cavity liquid passing deep hole, a rod cavity liquid passing hole and a rod cavity plug hole, a plug is mounted at the rod cavity plugging hole and comprises a shell and a steel ball; the plug end of the shell is closed, the other end of the shell is provided with an expansion hole, and the whole shell is cylindrical; a tooth surface structure which is annularly distributed is arranged on the peripheral surface of the shell and serves as an occlusal surface; the diameter of the steel balls is larger than the inner diameter of an expansion hole in the shell, the steel balls are used for being filled into the expansion hole to be in interference fit with the expansion hole and enable the shell to expand in the radial direction, and the meshing face of the plug is used for being meshed with the side wall of a rod cavity plugging hole. The scheme has the advantages of being good in sealing performance and high in sealing efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of piston rods, in particular to a double-deep-hole piston rod sealed by a ball-expanding high-pressure plug. Background Art

[0002] In order to facilitate the processing of the deep hole through the liquid in the rod cavity of the double deep hole piston rod, it is necessary to drill a process hole on the end face. After the processing of the deep hole through the liquid in the rod cavity is completed, the process hole needs to be blocked and sealed to ensure the normal use of the piston rod under high pressure conditions.

[0003] At present, the commonly used sealing process is plug welding, which has the following problems:

[0004] (1) During plug welding, due to improper control of welding parameters such as current and voltage, plug welding pad welding often occurs, causing welding slag, welding nodules, splashes, etc. to enter the deep hole of the rod cavity, affecting the cleanliness. In severe cases, it will scratch the seal and cause the jack function to fail;

[0005] (2) The process hole diameter is small, and it is easy for the molten pool and the side wall to not fuse or fuse poorly during plug welding, resulting in plugging and sealing failure. During the pressure test, liquid crossflow occurs between the rod cavity and the rodless cavity;

[0006] (3) After the plug welding is completed, the plug welding part needs to be flat-grinded to ensure the end surface flatness requirements, which affects production efficiency;

[0007] (4) The plug welding process requires grinding, preheating, welding, slag cleaning and other processes, which is not convenient for automated production.

[0008] Based on the above problems, it is necessary to redesign the structure of the double deep hole piston rod to avoid the above problems.

[0009] In order to solve the above problems, people have been seeking an ideal technical solution. Utility Model Content

[0010] The purpose of this utility model is to address the deficiencies in the existing technology and thus provide a double deep-hole piston rod with good sealing performance and high sealing efficiency, which solves the problems raised in the background such as easy leakage of liquid, difficulty in controlling cleanliness, and low sealing efficiency of the double deep-hole piston rod and adopts a ball-expanding high-pressure plug seal.

[0011] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a double deep hole piston rod sealed by a ball expansion type high-pressure plug, comprising a rod body, a rodless cavity liquid deep hole, a rod cavity liquid deep hole, a rod cavity liquid hole and a rod cavity plugging hole;

[0012] A plug is installed at the rod cavity blocking hole, and the plug includes a shell and a steel ball;

[0013] The plug end of the shell is closed, and the other end is provided with an expansion hole, and the shell is cylindrical as a whole;

[0014] The outer peripheral surface of the housing is provided with an annularly distributed tooth surface structure as an engaging surface;

[0015] The diameter of the steel ball is larger than the inner diameter of the expansion hole in the shell. The steel ball is used to fill the expansion hole to have an interference fit with the expansion hole and cause the shell to expand radially. The engaging surface of the plug is used to engage with the side wall of the rod cavity plugging hole.

[0016] Based on the above, the outer diameter of the shell is smaller than the inner diameter of the rod cavity blocking hole, and the length of the shell is smaller than the depth of the rod cavity blocking hole.

[0017] Based on the above, the allowable pressure of the ball expansion type high-pressure plug is 45MPa, the maximum working pressure is 70MPa, and the working temperature is -40~150℃.

[0018] Based on the above, the materials of the shell and the steel balls are both stainless steel.

[0019] Based on the above, the depth of the expansion hole in the shell is greater than the diameter of the steel ball.

[0020] Based on the above, the plug end of the shell is set to be a frustum shape.

[0021] Based on the above, the inner end surface of the expansion hole is a conical surface.

[0022] The utility model has substantial features and progress compared to the existing technology. Specifically, the utility model adopts a ball-expanding high-pressure plug to seal the rod cavity of the piston rod. By designing that the diameter of the steel ball is larger than the aperture of the shell, the steel ball is knocked into the expansion hole of the shell and is embedded in the piston rod body through the annular tooth surface on the outer peripheral surface, so that the sealing performance is good and the leakage rate is reduced.

[0023] The use of stainless steel can avoid seal failure due to rust, and reduce the difficulty of disassembling and repairing the jack due to unqualified pressure test after the piston rod and cylinder are assembled, which will lead to long cycle problems.

[0024] Since there is no welding process, problems such as spatter, weld nodules, weld slag and welding defects are avoided during the welding process, which greatly improves the cleanliness and extends the service life of the jack;

[0025] Due to its simple structure, the sealing cost is extremely low, only the cost of a ball-expansion high-pressure sealing plug; in conjunction with the assembly workstation, it can achieve automated precise positioning and installation, improving production efficiency. At the same time, it no longer requires high-level welders to perform plug welding processes, reducing leakage rates and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1The utility model is a structural schematic diagram of a double deep hole piston rod sealed by a ball expansion type high pressure plug.

[0027] Figure 2 The utility model is a schematic structural diagram of a rod body of a double-deep-hole piston rod sealed by a spherical expansion type high-pressure plug.

[0028] Figure 3 It is a structural schematic diagram of the ball expansion type high-pressure plug in the utility model.

[0029] Figure 4 It is a structural schematic diagram of the shell in the utility model.

[0030] In the figure: 1. Shell; 2. Steel ball; 3. Expansion hole; 4. Tooth surface structure; 11. Rod body; 12. Deep hole for liquid flow through rodless cavity; 13. Deep hole for liquid flow through rod cavity; 14. Liquid hole for rod cavity; 15. Rod cavity plugging hole; 16. Ball-expansion high-pressure plug. DETAILED DESCRIPTION

[0031] The technical solution of the present utility model is further described in detail below through specific implementation methods.

[0032] Example 1

[0033] like Figure 1-Figure 4 As shown, a double deep hole piston rod sealed with a ball expansion type high pressure plug includes a rod body 11, a rodless cavity liquid deep hole 12, a rod cavity liquid deep hole 13, a rod cavity liquid hole 14 and a rod cavity plugging hole 15.

[0034] A plug is installed at the rod cavity plugging hole 15 , and the plug is the spherical expansion type high pressure plug 16 . The occlusal surface of the spherical expansion type high pressure plug 16 is used to occlude with the side wall of the rod cavity plugging hole 15 .

[0035] Specifically, the spherical expansion type high-pressure plug includes a shell 1 and a steel ball 2.

[0036] The plug end of the shell 1 is closed, and the other end is provided with an expansion hole 3, and the shell 1 is cylindrical as a whole;

[0037] The outer peripheral surface of the housing 1 is provided with an annularly distributed tooth surface structure 4 as an occlusal surface;

[0038] The diameter of the steel ball 2 is larger than the inner diameter of the expansion hole 3 in the shell. The steel ball 2 is used to fill the expansion hole 3 to have an interference fit with the expansion hole 3 and cause the shell 1 to expand radially.

[0039] In this embodiment, the shell 1 and the steel ball 3 are both made of stainless steel, which is corrosion-resistant, can avoid sealing failure, and extend the service life.

[0040] In a preferred embodiment, the depth of the expansion hole in the housing is greater than the diameter of the steel ball, which can prevent the steel ball from easily falling out.

[0041] The plug end of the housing 1 is configured as a frustum, which allows for easier entry into the sealed hole.

[0042] The inner end surface of the expansion hole is a conical surface, which is easier to process on the one hand and can accommodate the entry of steel balls on the other hand.

[0043] Working principle:

[0044] In this embodiment, the inner diameter of the rod cavity blocking hole 15 is φd4(+0.05, 0), with a roundness of <0.05mm. The inner diameter of the rod cavity liquid depth hole 13 is φD2(0, -0.02). The outer diameter of the housing is smaller than the inner diameter of the rod cavity blocking hole, and the length of the housing is smaller than the depth of the rod cavity blocking hole.

[0045] The allowable pressure of the ball expansion type high-pressure plug is 45MPa, the maximum working pressure is 70MPa, and the working temperature is -40~150℃.

[0046] During installation, first ensure that the inner diameter of the hole port is slightly smaller than the outer diameter of the shell 1, and process a step at a certain depth of the hole. The diameter of the hole further inward from the step is significantly smaller than the outer diameter of the shell 1 to prevent the shell from entering too deep and provide support for the process of knocking in the steel ball 2; then knock the shell 1 into the hole port first, and after the shell 1 is completely entered into the hole, continue to knock in the steel ball 2. As the steel ball 2 enters the expansion hole 3, the steel ball 2 drives the shell 1 to expand radially, and the corrugated tooth surface distributed annularly on the outside of the shell 1 bites the inner wall of the hole to achieve high-pressure sealing.

[0047] In this embodiment, the outer diameter φD1 of the steel ball 2 is larger than the inner diameter φd2 of the housing 1, forming an interference fit that ensures the steel ball 2 is pre-pressed into the housing 1 and does not fall out. The outer diameter φD2 of the housing 1 is smaller than the inner diameter φd4 of the rod cavity plug hole 15, and the length L1 of the housing 1 is smaller than the depth L2 of the rod cavity plug hole 15. This ensures that the steel ball 2 of the ball-expanding high-pressure plug 16 can be installed in the rod cavity plug hole 15 before it is pressed in, and that the steel ball 2 does not extend beyond the end face of the piston rod body 11 after it is pressed in.

[0048] The holes that can be used for sealing are generally those with high pressure requirements, and the materials are mostly metal. They are especially suitable for sealing holes in hydraulic components.

[0049] Compared with the traditional plug welding sealing method, the utility model utilizes the ball-expanding high-pressure plug 16 to be placed in the rod cavity plugging hole 15, and presses the steel ball 2 into the shell 1. The axial extrusion of the steel ball 2 causes the shell 4 to expand radially, and the annular tooth surface actively engages and embeds into the inner surface of the rod cavity plugging hole 15 to achieve high-pressure sealing.

[0050] In a preferred embodiment, the pressing process of the steel balls is driven by the hydraulic power of the assembly workstation, which provides sufficient power while saving manpower, improving efficiency and enhancing automation.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and not to limit it; although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the utility model can still be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solution of the utility model, they should all be included in the scope of the technical solution for which protection is requested in the utility model.

Claims

1. A double deep hole piston rod sealed with a ball expansion high pressure plug, characterized in that: It includes a rod body, a rodless cavity liquid-passing depth hole, a rod cavity liquid-passing depth hole, a rod cavity liquid-passing hole and a rod cavity blocking hole; A plug is installed at the rod cavity blocking hole, and the plug includes a shell and a steel ball; The plug end of the shell is closed, and the other end is provided with an expansion hole, and the shell is cylindrical as a whole; The outer peripheral surface of the housing is provided with an annularly distributed tooth surface structure as an engaging surface; The diameter of the steel ball is larger than the inner diameter of the expansion hole in the shell. The steel ball is used to fill the expansion hole to have an interference fit with the expansion hole and cause the shell to expand radially. The engaging surface of the plug is used to engage with the side wall of the rod cavity plugging hole.

2. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 1, characterized in that: The outer diameter of the shell is smaller than the inner diameter of the rod cavity blocking hole, and the length of the shell is smaller than the depth of the rod cavity blocking hole.

3. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 1 or 2, characterized in that: The allowable pressure of the ball expansion type high-pressure plug is 45MPa, the maximum working pressure is 70MPa, and the working temperature is -40~150℃.

4. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 3, characterized in that: The shell and the steel balls are both made of stainless steel.

5. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 4, characterized in that: The depth of the expansion hole in the shell is greater than the diameter of the steel ball.

6. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 5, characterized in that: The plug end of the shell is configured to be frustum-shaped.

7. The double deep hole piston rod sealed with a spherical expansion type high pressure plug according to claim 5 or 6, characterized in that: The inner end surface of the expansion hole is a conical surface.

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