High-precision piston rod connecting structure of reciprocating compressor

Abstract

The high-precision piston rod connecting structure comprises a piston rod, the upper end of the piston rod is connected with a piston body, the lower end of the piston rod is connected with a crosshead, the upper end of the crosshead is connected with a positioning flange with a center hole, and the lower end of the piston rod is a reducing end transited through a conical surface section. The reducing end penetrates through the center hole of the positioning flange and is stretched and locked by a first fastening structure; the upper section of the center hole of the positioning flange is a taper hole matched with the conical surface section of the piston rod; the upper end of the piston rod penetrates into a center hole of the piston body, is stretched and locked by a second fastening structure and is provided with an anti-rotation structure. Automatic centering is achieved through conical surface matching, stable pre-tightening force is provided in cooperation with a double-fastening structure, the problems that a traditional connecting structure is insufficient in precision and poor in locking reliability are effectively solved, the operation precision and stability of a compressor are greatly improved, and meanwhile the compressor connecting structure has the advantages of being convenient to install and maintain and long in service life.

Description

Technical Field

[0001] This utility model relates to an improved invention of a reciprocating compressor, and more particularly to an improved invention of a high-precision piston rod connection structure for a reciprocating compressor. Background Technology

[0002] In reciprocating compressors, the piston rod is the core component for transmitting power, and the precision of its connection with the crosshead directly affects the compressor's operational stability, service life, and compression efficiency. Existing piston rod-crosshead connection structures mostly use a straight-hole fit with a single nut for locking, which presents several problems:

[0003] Insufficient precision: The coaxiality of the straight hole fit is difficult to control precisely. Under long-term reciprocating alternating loads, the fit clearance will gradually increase, causing the piston rod to wobble radially. This will not only aggravate the wear of the piston and cylinder inner wall, but also significantly reduce the operating precision of the compressor.

[0004] Poor locking reliability: The single-nut locking structure is prone to loosening under long-term vibration, and cannot continuously provide a stable preload to the piston rod, which in turn causes loosening and abnormal noise at the connection point. In severe cases, it may even pose a safety hazard of the piston rod falling off.

[0005] Installation and maintenance are inconvenient: The preload of traditional structures relies on the high torque of the nut, which not only requires high-quality operating tools, but also makes it difficult to accurately control the preload. The disassembly and reassembly process during later maintenance is cumbersome and consumes a lot of time and manpower. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a high-precision piston rod connection structure for a reciprocating compressor.

[0007] To solve the above-mentioned technical problems, this utility model adopts the following technical solution: a high-precision piston rod connection structure for a reciprocating compressor includes a piston rod, the upper end of which is connected to a piston body, and the lower end of which is connected to a crosshead. The crosshead has a positioning flange at its upper end, the positioning flange having a central hole, the lower end of the piston rod being a reduced-diameter end transitioned by a tapered section, the reduced-diameter end of the piston rod passing through the central hole of the positioning flange and being stretched and locked by a first fastening structure, and the upper section of the central hole of the positioning flange being a tapered hole that matches the tapered section of the piston rod.

[0008] The first fastening structure includes a first nut, which is threaded to the reduced diameter end of the piston rod. The first nut has a first threaded hole on the outer ring of the central threaded hole, and a first screw is installed in the first threaded hole. The upper end of the first screw is pressed against the lower end of the positioning flange, and the lower end of the first screw is the screwing end.

[0009] A first washer is provided between the first screw and the positioning flange.

[0010] The first screw hole is provided with a first annular step, and the first screw is provided with a first shoulder step. The first annular step constitutes the lower limit of the first shoulder step.

[0011] The lower end of the positioning flange is provided with a positioning step, which is matched and placed in the shaft hole of the crosshead. The corresponding crosshead fits the connecting surface of the positioning flange and the positioning step.

[0012] The positioning flange has an installation hole on the outer ring of the center hole, and a screw hole on the upper end of the corresponding crosshead. The positioning flange is fixed to the upper end of the crosshead by a stud, and the upper end of the stud is equipped with a raised cap nut.

[0013] The upper end of the piston rod is inserted into the central hole of the piston body and is stretched and locked by the second fastening structure. An anti-rotation structure is provided between the upper end of the piston rod and the piston body.

[0014] The second fastening structure includes a second nut, which is threaded to the upper end of the piston rod. The second nut has a second threaded hole on the outer ring of the central threaded hole, and a second screw is installed in the second threaded hole. The lower end of the second screw is pressed against the piston body, and the upper end of the second screw is a screwing end.

[0015] A second washer is provided between the second screw and the piston body.

[0016] The second screw hole is provided with a second annular step, and the second screw is provided with a second shoulder step. The second annular step constitutes the upper limit of the second shoulder step.

[0017] The beneficial effect of this utility model is the improved high-precision piston rod connection structure of the reciprocating compressor.

[0018] High-precision coaxiality assurance: Through the precise matching of the positioning flange and the positioning step of the crosshead, and the precise matching of the piston rod tapered section and the positioning flange tapered hole, the piston rod, crosshead, and piston body are automatically aligned, effectively ensuring the coaxiality and perpendicularity of the connection parts, greatly improving the operating accuracy of the compressor, and reducing the wear rate of the piston and cylinder.

[0019] Stable and reliable pre-tightening effect: The first and second fastening structures apply pre-tightening force by tightening the screws and pulling the nuts. The required installation torque is small, which can accurately provide pre-tension to the elastic part of the piston rod. In addition, the limiting structure of the first and second screws can eliminate the risk of loosening and falling off.

[0020] Improved ease of installation and maintenance: The raised cap nut of the positioning flange provides ample operating space, facilitating tool operation; the preload application method eliminates the need for high-torque tightening, reducing the requirements for operating tools and making it easier to accurately control the preload magnitude. The subsequent disassembly and reassembly process is simple, effectively shortening maintenance time.

[0021] Extending equipment lifespan: High-precision connections and stable preload reduce abnormal wear between components, lower the failure rate, and extend the overall lifespan of the reciprocating compressor, thereby reducing equipment maintenance costs. Attached Figure Description

[0022] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This utility model Figure 1 Enlarged view of part B.

[0025] Figure 3 This utility model Figure 1 Enlarged view of part A. Detailed Implementation

[0026] The accompanying drawings illustrate the structure of this utility model, and further details will be described below with reference to the drawings. In this embodiment, see the attached drawings. Figure 1-3 The high-precision piston rod connection structure of this reciprocating compressor includes a piston rod 1 with an oil slinger ring. The upper end of the piston rod 1 is connected to the piston body 2, and the lower end of the piston rod 1 is connected to the crosshead 3. A crosshead pin is assembled in the transverse hole of the crosshead 3 through a retaining ring and a positioning pin. The lower end of the crosshead 3 is machined with a process step for installation and positioning. The upper end of the crosshead 3 is connected to a positioning flange 4 with a center hole. The lower end of the piston rod 1 is a reduced-diameter end 11, which is transitioned by a tapered section 12. The reduced-diameter end 11 of the piston rod 1 passes through the center hole of the positioning flange 4 and is stretched and locked by a first fastening structure 5. The corresponding first fastening structure 5 is matched and located in the vertical hole of the crosshead 3. The upper section of the center hole of the positioning flange 4 is a tapered hole 41, which matches the tapered section 12 of the piston rod 1 to form tapered positioning and automatic centering.

[0027] As a further improved embodiment, the first fastening structure 5 includes a first nut 51, which is threaded to the reduced-diameter end 11 of the piston rod 1. The first nut 51 has a first threaded hole 52 around its central threaded hole, and a first screw 53 is fitted inside the first threaded hole 52. The upper end of the first screw 53 is pressed against the lower end of the positioning flange 4, and the lower end of the first screw 53 is the tightening end. This first fastening structure 5 has a small installation torque, pre-stretches the elastic part of the piston rod 1, and, in conjunction with the tapered surface connection, automatically finds its center and becomes coaxial.

[0028] As a further improved implementation, a first washer 54 is provided between the first screw 53 and the positioning flange 4 to avoid wear on the positioning flange 4 and to make the force on the positioning flange 4 more balanced.

[0029] As a further improved embodiment, the first screw hole 52 is provided with a first annular step 55, and the first screw 53 is provided with a first shoulder step 56. The first annular step 55 constitutes the lower limit of the first shoulder step 56, restricting the first screw 53 from disengaging from the first screw hole 52 and preventing damage to the crosshead 3 and crankcase. The first screw 53 is inserted from the top of the first screw hole 52, and the screwing end of the first screw 53 can pass through the first annular step 55.

[0030] As a further improved specific implementation, the lower end of the positioning flange 4 is provided with a positioning step 42, which is matched and placed in the shaft hole of the crosshead 3. The corresponding crosshead 3 fits the connecting surface of the positioning flange 4 and the positioning step 42 to ensure the coaxiality and perpendicularity of the piston rod 1.

[0031] As a further improved specific implementation, the outer ring of the center hole of the positioning flange 4 is provided with a mounting hole, and the upper end of the corresponding crosshead 3 is provided with a screw hole. The corresponding positioning flange 4 is fixed to the upper end of the crosshead 3 by a stud 6, and the upper end of the stud 6 is provided with a thrust washer and a raised cap nut 7. The raised cap nut 7 increases the installation space and facilitates the operation and tightening of the socket and torque wrench.

[0032] As a further improved specific implementation, the upper end of the piston rod 1 is inserted into the central hole of the piston body 2 and is stretched and locked by the second fastening structure 8. An anti-rotation structure 9 is provided between the upper end of the piston rod 1 and the piston body 2. The anti-rotation structure 9 consists of a matching anti-rotation pin and an anti-rotation hole.

[0033] As a further improved specific implementation, the second fastening structure 8 includes a second nut 81, which is threaded to the upper end of the piston rod 1, and the outer ring of the central screw hole of the second nut 81 is provided with a second screw hole 82, and a second screw 83 is provided in the second screw hole 82. The lower end of the second screw 83 is pressed against the piston body 2, and the upper end of the second screw 83 is a screwing end.

[0034] As a further improved implementation, a second washer 84 is provided between the second screw 83 and the piston body 2 to avoid wear on the piston body 2 and to make the force on the piston body 2 more balanced.

[0035] As a further improved embodiment, the second screw hole 82 is provided with a second annular step 85, and the second screw 83 is provided with a second shoulder step 86. The second annular step 85 constitutes the upper limit of the second shoulder step 86, restricting the second screw 83 from disengaging from the second screw hole 82 and preventing damage to the piston body 2 and piston cavity. The second screw 83 is inserted from below the second screw hole 82, and the screwing end of the second screw 83 can pass through the second annular step 85.

[0036] The connection and pre-tightening principle of the piston rod 1 and crosshead 3 of this utility model is as follows: First, the reduced-diameter end 11 of the lower end of the piston rod 1 is passed through the center hole of the positioning flange 4, so that the tapered section 12 of the piston rod 1 is precisely matched with the tapered hole 41 of the upper section of the center hole of the positioning flange 4, realizing automatic centering and ensuring the coaxiality of the piston rod 1 and the positioning flange 4. Then, the first fastening structure 5 is installed: the first nut 51 is threaded to the reduced-diameter end 11 of the piston rod 1, and the first screw 53 is installed in the first screw hole 52 of the first nut 51. By screwing the screw end of the first screw 53, the force of the upper end of the first screw 53 pressing against the lower end of the positioning flange 4 pulls the first nut 51 in the opposite direction, thereby pre-stretching the elastic part of the piston rod 1 and providing a stable pre-tightening force for the piston rod 1. Next, the positioning flange 4 is placed in the shaft hole of the crosshead 3 through the positioning step 42 at the lower end, so that the connecting surface of the crosshead 3 is in close contact with the positioning step 42 and the positioning flange 4, ensuring the coaxiality of the positioning flange 4 and the crosshead 3; then, through the mounting hole of the outer ring of the center hole, the positioning flange 4 is fixed to the upper end of the crosshead 3 with a stud and a heightened cap nut. The heightened cap nut provides sufficient space for installation and operation, facilitating the operation of the socket and torque wrench.

[0037] The connection and anti-rotation principle of the piston rod 1 and piston body 2 in this invention involves inserting the upper end of the piston rod 1 into the central hole of the piston body 2 and tightening it through the second fastening structure 8. A second nut 81 is threaded onto the upper end of the piston rod 1. Tightening the screw end of the second screw 83 causes the lower end of the second screw 83 to press against the piston body 2, and pulling the second nut 81 in the opposite direction achieves pre-tightening of the upper end of the piston rod 1. The anti-rotation structure 9 between the upper end of the piston rod 1 and the piston body 2 restricts the relative rotation between them, ensuring that the piston body 2 always moves synchronously with the piston rod 1 during reciprocating motion, thus avoiding wear and loosening of the connection caused by relative rotation.

[0038] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A high-precision piston rod connection structure for a reciprocating compressor, comprising a piston rod, wherein the upper end of the piston rod is connected to a piston body and the lower end of the piston rod is connected to a crosshead, characterized in that: The upper end of the crosshead is connected to a positioning flange, which has a central hole. The lower end of the piston rod is a reduced-diameter end, transitioned by a tapered section. The reduced-diameter end of the piston rod passes through the central hole of the positioning flange and is stretched and locked by a first fastening structure. The upper section of the central hole of the positioning flange is a tapered hole, which matches the tapered section of the piston rod.

2. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 1, characterized in that: The first fastening structure includes a first nut, which is threaded to the reduced diameter end of the piston rod. The first nut has a first threaded hole on the outer ring of the central threaded hole, and a first screw is installed in the first threaded hole. The upper end of the first screw is pressed against the lower end of the positioning flange, and the lower end of the first screw is the screwing end.

3. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 2, characterized in that: A first washer is provided between the first screw and the positioning flange.

4. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 2, characterized in that: The first screw hole is provided with a first annular step, and the first screw is provided with a first shoulder step. The first annular step constitutes the lower limit of the first shoulder step.

5. The high-precision piston rod connection structure of the reciprocating compressor as described in claim 1, characterized in that: The lower end of the positioning flange is provided with a positioning step, which is matched and placed in the shaft hole of the crosshead. The corresponding crosshead fits the connecting surface of the positioning flange and the positioning step.

6. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 1, characterized in that: The positioning flange has an installation hole on the outer ring of the center hole, and a screw hole on the upper end of the corresponding crosshead. The positioning flange is fixed to the upper end of the crosshead by a stud, and the upper end of the stud is equipped with a raised cap nut.

7. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 1, characterized in that: The upper end of the piston rod is inserted into the central hole of the piston body and is stretched and locked by the second fastening structure. An anti-rotation structure is provided between the upper end of the piston rod and the piston body.

8. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 7, characterized in that: The second fastening structure includes a second nut, which is threaded to the upper end of the piston rod. The second nut has a second threaded hole on the outer ring of the central threaded hole, and a second screw is installed in the second threaded hole. The lower end of the second screw is pressed against the piston body, and the upper end of the second screw is a screwing end.

9. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 8, characterized in that: A second washer is provided between the second screw and the piston body.

10. The high-precision piston rod connecting structure of a reciprocating compressor according to claim 8, characterized in that: The second screw hole is provided with a second annular step, and the second screw is provided with a second shoulder step. The second annular step constitutes the upper limit of the second shoulder step.

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