Piston assembly and oil cylinder with same

Abstract

The piston assembly comprises a cylinder body, a piston rod and the piston assembly, an oil cavity is formed in the cylinder body, an oil port communicated with the oil cavity is formed in the cylinder body, the piston rod is arranged in the cylinder body in a penetrating mode, the piston assembly is arranged in the cylinder body to separate the oil cavity, and the piston assembly is connected with the piston rod. In the assembling process of the piston assembly and the piston rod, the matching face of the piston assembly is suitable for being converted between interference fit and clearance fit with the piston rod. When the piston rod and the piston assembly of the oil cylinder are assembled, firstly, the matching face between the piston rod and the piston assembly is pressurized, so that the connection relation between the piston assembly and the piston rod is changed into clearance fit from initial interference fit, and after the piston assembly reaches a proper position on the piston rod, the piston assembly is separated from the piston assembly. That is to say, the clearance fit between the piston assembly and the piston rod is changed into interference fit again, so that the adjustment of the assembly position of the piston assembly and the piston rod is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of oil cylinders, in particular to a piston assembly and an oil cylinder having the same. Background Art

[0002] At present, some of the oil cylinder structures on the market are processed as a whole with the piston and the piston rod, which will lead to serious waste of raw materials, large processing volume, high cost and long processing cycle. Another part of the structure is processed separately, but the existing separate processing technology on the market also has obvious disadvantages. For example, when the thermal expansion assembly method is used for assembly, the fixation of the piston and the piston rod is achieved by the interference fit between them to generate friction. When assembling the oil cylinder, the piston needs to be heated to more than 650 degrees. After the piston is heated, it will expand due to physical heat. At this time, the piston rod is quickly pressed into the piston. After the piston cools down, the piston shrinks to its original size and holds the piston rod tightly. The interference fit surface of the piston and the piston rod will form a strong positive stress, so as to achieve a larger static friction between the piston rod and the piston, so that the piston rod and the piston are connected as one. However, this assembly method has the following defects:

[0003] First, the piston needs to be heated to a temperature of over 100 degrees before being quickly assembled, which makes assembly in a workshop difficult and dangerous.

[0004] Secondly, when the temperature of the piston rises, only the radial dimension of the piston needs to increase, but the axial dimension will also increase. This causes that when the piston cools and shrinks, at a certain critical point, the friction between the piston and the piston rod is large enough, and the piston holds the piston rod tightly in the axial direction. However, the piston has not yet returned to room temperature, and the piston will continue to shrink. The deformation of the piston in the radial direction cannot be restored due to the influence of friction, resulting in local stress. This plastic deformation will affect the dimensional accuracy of the piston and the interference between the piston rod and the piston, and further affect the friction between the two.

[0005] In addition, after the piston is assembled, the cooling time is very slow. After testing, even if it is heated to 450 degrees, there is still residual temperature after 4 hours, and the assembly efficiency is low;

[0006] Furthermore, due to the deformation of the piston after cooling from high temperature and the difficulty of high temperature operation, the connection position of the piston and the piston rod is difficult to control and has poor accuracy, and it cannot be adjusted after assembly, thus affecting the inherent performance of the product.

[0007] In view of this, it is necessary to design a piston assembly and an oil cylinder using the piston assembly to solve the above problems. Utility Model Content

[0008] The utility model aims to solve at least one of the technical problems existing in the prior art.

[0009] To this end, the utility model provides a piston assembly, which can adjust the installation position between the piston rod and the piston multiple times, and will not be affected by external factors such as high temperature during assembly, so the assembly time is short and the safety is higher.

[0010] According to a first aspect of the utility model, a piston assembly is provided, comprising:

[0011] A piston rod and a piston assembly component, wherein the piston assembly component is sleeved on the piston rod, and the piston assembly component includes a piston body and an assembly oil port component opened in the piston body, so as to transport oil between the mating surface of the piston body and the piston rod through the assembly oil port component, and the oil is suitable for simultaneously pressing the piston body and the piston rod, so that the mating surface of the piston assembly component is suitable for switching between an interference fit and a clearance fit with the piston rod.

[0012] Further preferably, the assembly oil port assembly includes multiple first sealing rings, the inner wall of the piston body is provided with first annular grooves near both sides, the multiple first sealing rings are respectively arranged in each of the first annular grooves, and an assembly adjustment cavity is formed between the multiple first sealing rings and the piston rod.

[0013] Preferably, the assembly oil port assembly further comprises an oil supply assembly, and the oil supply assembly is adapted to be connected to the assembly regulating cavity so as to be able to input oil into the assembly regulating cavity or output oil in the assembly regulating cavity.

[0014] Further preferably, the piston rod comprises a piston rod main body section and an assembly fitting section provided at least at one end of the piston rod main body section, and the assembly fitting section is clearance-fitted with the piston body.

[0015] Further preferably, the diameter of the assembly fitting section is smaller than the diameter of the piston rod main body section.

[0016] Further preferably, an assembly chamfer is formed between the assembly fitting section and the piston rod main body section.

[0017] Further preferably, the value range of the inclination angle a of the assembly chamfer is: 0°<a<20°.

[0018] Further preferably, the length of the assembly fitting section is greater than the length of the piston body.

[0019] Further preferably, the outer side wall of the piston body is provided with a second annular groove, and a second sealing ring is provided in the second annular groove.

[0020] The second aspect of the utility model provides an oil cylinder, comprising:

[0021] The piston assembly according to the first aspect of the utility model;

[0022] A cylinder body, wherein an oil chamber is formed in the cylinder body and the piston assembly is accommodated therein, and an oil port communicating with the oil chamber is opened on the cylinder body;

[0023] Guide sleeves are arranged at both ends of the cylinder body, and the piston rod of the piston assembly simultaneously passes through the guide sleeves located at both ends to guide the piston rod to reciprocate along its axial direction through the guide sleeves.

[0024] The beneficial effect of the utility model is that when the piston rod and the piston assembly of the oil cylinder are assembled, the mating surface between the two is firstly pressurized so that the connection relationship between the piston assembly and the piston rod is changed from the initial interference fit to a clearance fit; when the piston assembly reaches the appropriate position on the piston rod, the pressure is released so that the clearance fit between the piston assembly and the piston rod is changed again to an interference fit, thereby conveniently realizing the adjustment of the assembly position of the piston assembly and the piston rod; in addition, this assembly method will not be affected by external factors, and the time for adjusting the assembly position is short, and the safety is high.

[0025] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model are realized and obtained by the structures specifically pointed out in the description, claims and drawings.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0028] Figure 1 This is a cross-sectional view of the overall structure of the oil cylinder of the utility model;

[0029] Figure 2 This is a three-dimensional diagram of the internal structure of the oil cylinder of the utility model after assembly;

[0030] Figure 3 It is a three-dimensional enlarged view of the piston assembly component and the piston rod of the utility model when assembled;

[0031] Figure 4 It is an enlarged view of the assembly chamfer of the utility model.

[0032] In the figure:

[0033] 1. Cylinder body; 11. Oil chamber; 12. Oil port; 13. Assembly adjustment chamber;

[0034] 2. Piston rod; 21. Piston rod main section; 22. Assembly matching section; 23. Assembly chamfer;

[0035] 3. Piston assembly component; 31. Piston body; 32. Assembly oil port component; 321. Oil supply component; 322. First sealing ring;

[0036] 4. Guide sleeve. DETAILED DESCRIPTION

[0037] The present invention is now described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention. In the description of the present invention, it should be understood that, unless otherwise specified, the meaning of "multiple" is two or more.

[0038] See also Figure 1 to Figure 2 A specific embodiment of the utility model is a cylinder, comprising a cylinder body 1, a piston rod 2 passing through the cylinder body 1, and a piston assembly 3 arranged in the cylinder body 1 and connected to the piston rod 2. In one embodiment, the cylinder is a double-rod cylinder. An oil chamber 11 is formed in the cylinder body 1, and an oil port 12 connected to the oil chamber 11 is provided on the cylinder body 1, so that hydraulic oil can be transported into the oil chamber 11 through the oil port 12. In addition, the piston assembly 3 provided in the cylinder body 1 can separate the oil chamber 11 formed in the cylinder body 1, that is, there is an oil chamber 11 on each side of the piston assembly 3. When hydraulic oil is injected into the oil chamber 11 on one side of the piston assembly 3, the piston rod 2 moves toward the oil chamber 11 on the other side of the piston assembly 3 under the action of the hydraulic oil. In addition, guide sleeves 4 are provided at both ends of the cylinder body 1, and the piston rod 2 passes through the guide sleeves 4 at both ends of the cylinder body 1 at the same time. The space of the cylinder body 1 between the guide sleeves 4 and the piston assembly component 3 is an oil chamber 11 for pushing the piston rod 2 to realize axial reciprocating motion, and by injecting hydraulic oil into different oil chambers 11, the piston rod 2 can be pushed to move along the direction defined by the guide sleeves 4.

[0039] See also Figure 3A piston assembly according to a specific embodiment of the utility model includes a piston rod 2 and a piston assembly assembly 3, wherein, in order to facilitate the assembly of the piston assembly assembly 3 and the piston rod 2, convenient assembly between the two is achieved mainly by adjusting the matching relationship between the piston assembly assembly 3 and the piston rod 2. The matching relationship between the piston assembly assembly 3 and the piston rod 2 includes a clearance fit and an interference fit, and the piston assembly assembly 3 and the piston rod 2 can switch between the clearance fit and the interference fit. wherein, when the two are in a clearance fit state, the piston assembly assembly 3 can move to any position on the piston rod 2, and when the two are in an interference fit state, the piston assembly assembly 3 is fixed on the piston rod 2 and can no longer move.

[0040] See also Figure 1 and 3 The piston rod 2 includes a piston rod main section 21 and at least one assembly matching section 22, at least one assembly matching section 22 is arranged on one side of the piston rod main section 21, the piston assembly component 3 includes a piston body 31 and an assembly oil port component 32 opened in the piston body 31, wherein the assembly oil port component 32 includes an oil supply component 321 and a plurality of first sealing rings 322, a first annular groove is provided on the inner wall of the piston body 31 near the two sides, and the plurality of first sealing rings 322 are respectively arranged in the corresponding first annular grooves, and an assembly adjustment cavity 13 can be formed between the matching surfaces of the plurality of first sealing rings 322 and the piston rod main section 21 and the piston assembly component 3, the oil supply component 321 is connected to the assembly adjustment cavity 13, and oil can be transported into the assembly adjustment cavity 13 through the oil supply component 321. It should be noted that the assembly adjustment cavity 13 is mainly formed by a plurality of first sealing rings 322 abutting against the surface of the piston rod 2, so that the formed assembly adjustment cavity 13 becomes a closed cavity, thereby ensuring that no leakage occurs after the oil is injected therein, and at the same time, high pressure is generated in the assembly adjustment cavity 13 to compress the piston body 31 and the piston rod 2 to deform.

[0041] Specifically, during assembly, the piston assembly component 3 is first pushed into the assembly matching section 22 of the piston rod 2. Since the diameter of the assembly matching section 22 is smaller than the inner ring diameter of the piston body 31 of the piston assembly component 3, the piston body 31 can be easily pushed into the assembly matching section 22. At this time, there is a clearance fit between the assembly matching section 22 and the piston body 31. In this embodiment, two assembly matching sections 22 are provided, which are respectively located on both sides of the axial direction of the piston rod main section 21 and are integrally formed with the piston rod main section 21.

[0042] In order to facilitate the piston assembly component 3 to be pushed into the piston rod main section 31, it is necessary to continuously inject oil into the assembly adjustment cavity 13. As the oil is continuously injected, the oil can simultaneously press the piston body 31 and the piston rod 2, so that the piston body 31 is subjected to the internal pressure generated by the oil and the diameter is strained and expanded, and the piston rod 2 is subjected to the external pressure and the diameter is strained and compressed, and then by adjusting the amount of oil injected into the assembly adjustment cavity 13, the size of the inner ring diameter of the piston body 31 can be adjusted. In this embodiment, the inner ring diameter of the piston body 31 is adjusted to be larger than the diameter of the piston rod main section 21 through the assembly adjustment cavity 13, so that the position of the piston body 31 on the piston rod main section 21 can be adjusted.

[0043] In addition, when oil is transported into the assembly adjustment cavity 13 through the oil supply component 321, it is necessary to wait until the piston body 31 is completely pushed into the assembly fitting section 22 of the piston rod 2 before supplying oil into the assembly adjustment cavity 13 through the oil supply component 321. Therefore, the length of the assembly fitting section 22 needs to be set to be greater than the axial length of the piston body 31.

[0044] See also Figure 4 , wherein, as the piston assembly component 3 is continuously pushed toward the piston rod main section 21, the volume of the assembly adjustment chamber 13 formed between the piston assembly component 3 and the piston rod 2 gradually decreases. Since the diameter of the piston rod main section 21 is larger than the assembly matching section 22 of the piston rod 2, an assembly chamfer 23 is also provided between the two. By providing the assembly chamfer 23, when the first sealing ring 322 provided on the inner wall of the piston body 31 moves from the assembly matching section 22 to the piston rod main section 21, it can smoothly transition from the assembly matching section 22 to the assembly matching section 22 along the assembly chamfer 23, wherein the value range of the inclination angle a of the assembly chamfer 23 is 0°<a<20°.

[0045] In one embodiment, a second annular groove is disposed on the outer side wall of the piston body 31, and a second sealing ring is disposed in the second annular groove.

[0046] After the piston assembly component 3 transitions from the assembly matching section 22 to the appropriate position on the piston rod main section 21, the oil in the assembly adjustment cavity 13 is unloaded through the oil supply component 321. At this time, the piston body 31 and the piston rod main section 21 are changed from clearance fit to interference fit again, and the piston body 31 can be fixed on the piston rod main section 21, and then the oil inlet of the oil supply component 321 is blocked. If it is necessary to adjust the position of the piston body 31 on the piston rod main section 21 again, oil can be injected into the assembly adjustment cavity 13 again through the oil supply component 321, so that the piston body 31 and the piston rod main section 21 are restored to clearance fit again, and the relative position of the piston body 31 and the piston rod main section 21 can be adjusted again. Therefore, by adjusting the matching relationship between the piston assembly component 3 and the piston rod 2, the installation distance of the oil cylinder can be adjusted multiple times, and during the assembly process of the two, it will not be affected by other external factors such as high temperature, which will cause plastic deformation of the body, and the whole adjustment method is simple, the adjustment time is short, and the safety is higher.

[0047] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0048] The above description is based on the ideal embodiment of the utility model. Through the above description, relevant staff can make various changes and modifications without deviating from the technical concept of the utility model. The technical scope of the utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A piston assembly, characterized in that: include: A piston rod (2) and a piston assembly component (3), wherein the piston assembly component (3) is sleeved on the piston rod (2), and the piston assembly component (3) comprises a piston body (31) and an assembly oil port component (32) provided in the piston body (31), so as to transport oil between the matching surface of the piston body (31) and the piston rod (2) via the assembly oil port component (32), wherein the oil is suitable for simultaneously pressing the piston body (31) and the piston rod (2), so that the matching surface of the piston assembly component (3) and the piston rod (2) are switched between an interference fit and a clearance fit.

2. The piston assembly according to claim 1, characterized in that The assembly oil port assembly (32) includes a plurality of first sealing rings (322), the inner wall of the piston body (31) is provided with first annular grooves near both sides, the plurality of first sealing rings (322) are respectively arranged in each of the first annular grooves, and an assembly adjustment cavity (13) is formed between the plurality of first sealing rings (322) and the matching surfaces of the piston rod (2) and the piston assembly assembly (3).

3. The piston assembly according to claim 2, characterized in that The assembly oil port assembly (32) further comprises an oil supply assembly (321), wherein the oil supply assembly (321) is connected to the assembly adjustment cavity (13) so as to be able to input oil into the assembly adjustment cavity (13) or output oil from the assembly adjustment cavity (13).

4. The piston assembly according to claim 2, characterized in that: The piston rod (2) comprises a piston rod main section (21) and an assembly fitting section (22) provided at least at one end of the piston rod main section (21); the assembly fitting section (22) is clearance-fitted with the piston body (31).

5. The piston assembly according to claim 4, characterized in that The diameter of the assembly matching section (22) is smaller than the diameter of the piston rod main body section (21).

6. The piston assembly according to claim 5, characterized in that An assembly chamfer (23) is formed between the assembly matching section (22) and the piston rod main body section (21).

7. The piston assembly according to claim 6, characterized in that The value range of the inclination angle a of the assembly chamfer (23) is: 0°<a<20°.

8. The piston assembly according to claim 4, characterized in that The length of the assembly fitting section (22) is greater than the length of the piston body (31).

9. The piston assembly according to claim 1, characterized in that The outer side wall of the piston body (31) is provided with a second annular groove, and a second sealing ring is provided in the second annular groove.

10. An oil cylinder, characterized in that: include: The piston assembly according to any one of claims 1 to 9; A cylinder body (1), wherein an oil chamber (11) is formed in the cylinder body (1) and accommodates the piston assembly, and an oil port (12) connected to the oil chamber (11) is opened on the cylinder body (1); Guide sleeves (4), the guide sleeves (4) are arranged at both ends of the cylinder body (1), and the piston rod (2) of the piston assembly simultaneously passes through the guide sleeves (4) located at both ends, so as to guide the piston rod (2) to reciprocate along its axial direction through the guide sleeves (4).

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