Low-temperature aluminum piston anti-loosening structure for reciprocating compressor

Abstract

The utility model discloses a low-temperature aluminum piston anti-loose structure for a reciprocating compressor, which comprises a piston body and a piston rod, a supporting ring is arranged on the outer circle of the piston body, and the low-temperature aluminum piston anti-loose structure is characterized in that the piston body is an aluminum pressure-bearing piston body, the piston rod is a steel piston rod, and the piston rod is fixedly arranged in a shaft hole of the piston body in a penetrating mode. A limiting step and a locking nut are arranged on the piston rod, mounting grooves are formed in the positions, corresponding to the front end and the rear end of the piston body shaft hole, of the piston body respectively, the mounting grooves are formed around the piston body shaft hole, steel pressure-bearing rings are arranged in the mounting grooves, and the limiting step and the locking nut are matched with the corresponding steel pressure-bearing rings in a limiting mode respectively. The aluminum piston is adopted, the weight is light, manufacturing is easy, the specific pressure of the supporting ring is small, and the service life is longer.

Description

Technical Field

[0001] The utility model relates to an improved invention for a reciprocating compressor, in particular to an improved invention for an anti-loosening structure of a low-temperature aluminum piston used in a reciprocating compressor. Background Art

[0002] The operating temperature of the low-temperature piston in the cylinder can reach -160℃. The weight of the piston of the reciprocating compressor affects the stability of the unit operation. Both stainless steel pistons and aluminum pistons can be used at low temperatures, but aluminum pistons have the advantages of light weight, simple manufacturing, and small support ring pressure. Under the same size as stainless steel pistons, aluminum pistons are lighter and the service life of the support rings is longer.

[0003] At low temperatures, the shrinkage amount = length * expansion coefficient. The expansion coefficient of the piston rod is 10*10-6 for steel, and the expansion coefficient of the piston body is 23*10-6 for aluminum alloy. Under the same working temperature of -160℃, the shrinkage of the aluminum piston is about 2 times that of the piston rod in the same length direction. The difference in shrinkage amount will cause the piston to loosen and fall off at low temperatures. In order to ensure the pre-tightening of the piston at low temperatures and avoid loosening, changing the piston contraction length becomes an effective means. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a low-temperature aluminum piston anti-loosening structure for a reciprocating compressor.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions: the low-temperature aluminum piston anti-loosening structure for the reciprocating compressor includes a piston body and a piston rod, and a support ring is provided on the outer circle of the piston body, and is characterized in that: the piston body is an aluminum pressure-bearing piston body, and the piston rod is a steel piston rod. The piston rod is fixedly inserted into the piston body shaft hole, and a limiting step and a locking nut are provided on the piston rod. The piston body corresponding to the front and rear ends of the piston body shaft hole is respectively provided with mounting grooves, the mounting grooves are arranged around the piston body shaft hole, and a steel pressure ring is provided in the mounting groove, and the limiting step and the locking nut are respectively limited and matched with the corresponding steel pressure ring.

[0006] A gap of 0.5 to 2 mm is reserved between the outer circle of the steel pressure ring and the ring wall of the installation groove.

[0007] The inner end of the annular wall of the mounting groove is provided with a rounded corner.

[0008] A gap of 0.5 to 2 mm is reserved between the outer circle of the locking nut and the annular wall of the mounting groove.

[0009] The contracted length of the piston rod is L1, and the contracted length of the piston body is L2. When the operating temperature is -100~-160°C, L2=0.5*L1; when the operating temperature is -66~-99°C, L2=0.7*L1.

[0010] The beneficial effect of the utility model is that the improved low-temperature aluminum piston anti-loosening structure for reciprocating compressors adopts an aluminum piston, which is light in weight, simple to manufacture, has a small supporting ring specific pressure and a longer service life; a steel pressure ring is provided to change the piston contraction length to avoid loosening of the piston due to pre-tightening under low-temperature conditions; chamfered corners are provided on the pressure-bearing surfaces of the aluminum piston and the steel part to avoid stress concentration and cracks caused by contraction and expansion of the aluminum piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings.

[0012] Figure 1 It is a structural diagram of the present utility model. DETAILED DESCRIPTION

[0013] The accompanying drawings show the structure of the present invention, and the following further describes its relevant details in conjunction with the accompanying drawings. Figure 1 The low-temperature aluminum piston anti-loosening structure for the reciprocating compressor includes a piston body 1 and a piston rod 2. A supporting ring 3 is provided on the outer circle of the piston body 1. The piston body 1 is an aluminum pressure-bearing piston body, and the piston rod 2 is a steel piston rod. The piston rod 2 is fixedly inserted into the axial hole of the piston body 1. A limiting step 4 and a locking nut 5 are provided on the piston rod 2. The piston body 1 corresponding to the front and rear ends of the axial hole of the piston body 1 is respectively provided with mounting grooves 6. The mounting grooves 6 are arranged around the axial hole of the piston body 1, and a steel pressure ring 7 is provided in the mounting groove 6. The limiting steps 4 and the locking nut 5 are respectively limited and matched with the corresponding steel pressure ring 7. Specifically, the locking nut 5 abuts against the end surface of the steel pressure ring 7, and the limiting step 4 is embedded in the end surface of the steel pressure ring 7.

[0014] As a further improved specific implementation method, a gap of 0.5 to 2 mm is reserved between the outer circle of the steel pressure ring 7 and the ring wall of the installation groove 6 to prevent deformation due to shrinkage and extrusion in the diameter direction.

[0015] As a further improved specific implementation method, the inner end of the ring wall of the installation groove 6 is provided with a chamfer 8 to prevent stress concentration and cracks caused by the shrinkage and expansion of the aluminum piston body 1.

[0016] As a further improved specific implementation method, a gap of 0.5 to 2 mm is reserved between the outer circle of the locking nut 5 and the annular wall of the mounting groove 6 to prevent deformation due to shrinkage and extrusion in the diameter direction.

[0017] As a further improved embodiment, the retracted length of the piston rod 2 is L1, and the retracted length of the piston body 1 is L2. When the operating temperature is -100 to -160°C, L2 = 0.5 * L1; when the operating temperature is -66 to -99°C, L2 = 0.7 * L1. This prevents loosening of the piston preload at low temperatures.

[0018] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A low-temperature aluminum piston anti-loosening structure for a reciprocating compressor, comprising a piston body and a piston rod, wherein a support ring is provided on the outer circumference of the piston body, characterized in that: The piston body is an aluminum pressure-bearing piston body, and the piston rod is a steel piston rod. The piston rod is fixedly inserted into the piston body shaft hole. A limiting step and a locking nut are provided on the piston rod. The piston body corresponding to the front and rear ends of the piston body shaft hole are respectively provided with mounting grooves. The mounting grooves are arranged around the piston body shaft hole, and a steel pressure ring is provided in the mounting groove. The limiting step and the locking nut are respectively limited and matched with the corresponding steel pressure ring.

2. The low-temperature aluminum piston anti-loosening structure for a reciprocating compressor according to claim 1, characterized in that: A gap of 0.5 to 2 mm is reserved between the outer circle of the steel pressure ring and the ring wall of the installation groove.

3. The low-temperature aluminum piston anti-loosening structure for a reciprocating compressor according to claim 1 or 2, characterized in that: The inner end of the annular wall of the mounting groove is provided with a rounded corner.

4. The low-temperature aluminum piston anti-loosening structure for a reciprocating compressor according to claim 1, characterized in that: A gap of 0.5 to 2 mm is reserved between the outer circle of the locking nut and the annular wall of the mounting groove.

5. The low-temperature aluminum piston anti-loosening structure for a reciprocating compressor according to claim 1, characterized in that: The contracted length of the piston rod is L1, and the contracted length of the piston body is L2. When the operating temperature is -100~-160°C, L2=0.5*L1; when the operating temperature is -66~-99°C, L2=0.7*L1.

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