Piston part with piston ring having functions of sealing and supporting ring

Abstract

The piston component comprises a piston body, a supporting ring and a plurality of piston rings, the supporting ring and the piston rings are arranged on the piston body, a plurality of ring grooves are formed in the piston body and used for arranging the supporting ring and the piston rings respectively, and no gap exists between the piston rings and the bottom diameters of the ring grooves. The piston ring has the sealing and supporting functions, and the supporting ring has the supporting function. According to the invention, the oil and oil-free working condition universal design of piston parts of the same model, the same specification and the same parameter is realized, the modularization and standardization level of the design is improved, the product quality is stabilized, and the operation reliability of the compressor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical equipment, and more specifically, to a piston component in which a piston ring has both sealing and supporting ring functions. Background Art

[0002] like Figure 1 As shown, the cylinder component 1, piston component 2, cylinder pressure packing 3 and cylinder head 4 of the reciprocating compressor constitute a closed working chamber with variable volume. One side of the piston component is the cylinder shaft end compression chamber 5, and the other side is the cylinder head end compression chamber 6. The piston component performs reciprocating linear motion in the cylinder to realize the processes of suction, compression, exhaust, expansion, etc. Figure 2 As shown, the piston component is composed of a piston body 7, a piston rod 8, a piston nut 9, a piston ring 10, a support ring 11 and other parts. Different numbers of piston rings are arranged on the piston body according to the size of the sealing pressure difference at both ends of the piston for sealing the compressed medium. The piston body is also provided with a support ring for supporting the weight of the piston body and the piston rod and maintaining the linearity of the operation of the piston component. Under normal circumstances, the piston ring only plays the role of sealing the compressed medium and does not participate in the support of the piston. There is a gap of more than 1mm between the bottom diameter of the piston ring and the bottom diameter of its ring groove.

[0003] Reciprocating compressors can be divided into oil-lubricated and oil-free according to whether the cylinder is oil-filled. For lubricated horizontal cylinders, the allowable specific pressure of the support ring specified in the API618 standard shall not be greater than 0.07 N / mm 2 For non-lubricated horizontal cylinders, the API618 standard stipulates that the allowable specific pressure of the support ring shall not exceed 0.035 N / mm 2 This specific pressure value is obtained by adding the mass of the entire piston assembly to half of the piston rod mass divided by the projection area of ​​the support ring perpendicular to the piston rod axis at 120° (see formula 3 for calculation formula).

[0004] from Figure 1 It can be seen that the cylinder compression chamber length L is related to the piston stroke S and piston length L 1 and the fixed cylinder axial clearance, as shown in Formula 1. For the selected model, the stroke S is a fixed value, the cylinder axial clearance is also a fixed value, and only the piston length L 1 Is a variable.

[0005] L=S(piston stroke)+L 1 +4 (cylinder axial clearance) mm (Formula 1) from Figure 2 It can be seen that the piston body length L 1It is associated with data such as the distance F between the end piston ring and the end face of the piston body, the width H and quantity of the piston ring groove, the width T and quantity of the piston body ring groove, and the width Z of the support ring. Under the conditions that the cylinder diameter, pressure, and valve size parameters are determined, the dimension F, the width H and quantity of the piston ring, and the width T and quantity of the piston body ring groove are determined. Only the width Z of the support ring is a variable, and the width Z of the support ring is related to factors such as the mass of the piston assembly plus the mass of the piston rod and whether the cylinder is lubricated.

[0006] L 1 =2×F+n×H+n×T+Zmm (Formula 2) n is the number of piston ring grooves and piston body ring groove land widths; P K = ( M PA + M R / 2 ) / (0.866×D×Z )N / mm (Formula 3) Then: Z = ( M PA + M R / 2 ) / (0.866×D×P K )mm (Formula 4) Where: P K = specific pressure on the support ring, N / mm; M PA = weight of piston assembly, N; M R = weight of piston rod, N; D = cylinder bore diameter, mm; Z = axial length of support ring, mm.

[0007] API618 standard stipulates that the allowable specific pressure of the lubricated horizontal cylinder piston support ring shall not exceed 0.07 N / mm 2 The permissible specific pressure of the piston support ring of oil-free horizontal cylinder shall not be greater than 0.035 N / mm 2 The permissible specific pressure of the oil-free lubricated piston support ring is half of that of the oil-lubricated one. Under the conditions of the same cylinder diameter, pressure, and valve size, according to formula 4, the axial length Z value of the piston support ring of the oil-free lubricated unit is twice that of the lubricated unit, that is, the oil-free piston length L of the cylinder with the same specifications and parameters is 1 Compared with oil, the cylinder is longer by 1 Z value, the corresponding cylinder compression chamber increases by 1 Z value, and the total length of the cylinder also increases by 1 Z value.

[0008] The result is that piston parts and cylinder parts of the same model, specification and parameters need to be designed in two specifications due to the requirements of oil- and oil-free working conditions, which is not conducive to the standardization, modularization and universality of the design, nor is it conducive to the cost control and mass production of the product. In addition, the lengthening of the piston body and piston rod increases the reciprocating mass, the reciprocating inertia force, the comprehensive piston force of the unit, and the reliability of the unit operation. Therefore, it is necessary to design a piston part that takes into account both oil- and oil-free working conditions, improves the modularization, standardization and universality of the design, stabilizes product quality, and enhances the reliability of the unit operation. Summary of the invention

[0009] One object of the present invention is to provide a piston component whose piston ring has both sealing and supporting ring functions, so as to realize universal design of piston components of the same model, specification and parameters for oil- and oil-free working conditions, improve the modularization and standardization level of the design, stabilize product quality and enhance the reliability of compressor operation.

[0010] In order to solve the above technical problems, the present invention provides a piston component having a piston ring with both sealing and supporting ring functions, comprising a piston body and a supporting ring and multiple piston rings arranged on the piston body, the piston body being provided with multiple ring grooves for respectively arranging the supporting ring and the multiple piston rings, and there is no gap between the multiple piston rings and the bottom diameters of the ring grooves, so that the piston ring has both sealing and supporting functions, and the support ring has a supporting function.

[0011] Preferably, the size of the piston ring is increased to completely fill the corresponding ring groove, or the size of the corresponding ring groove of the piston ring is reduced so that the corresponding piston ring completely fills the corresponding ring groove, thereby achieving no gap between the piston ring and the bottom diameter of its ring groove.

[0012] Preferably, the total width of the piston ring is n×H≥Z, wherein Z is the axial length of the support ring, H is the width of the piston ring, and n is the number of the piston rings, all in mm.

[0013] Preferably, the overall width of the piston ring is designed according to the allowable specific pressure of the support ring specified in API618 standard.

[0014] Preferably, the specific design process is as follows: According to API618 standard, the permissible specific pressure standard of the support ring of a lubricated horizontal cylinder is twice the permissible specific pressure standard of the support ring of a non-lubricated horizontal cylinder; The specific pressure value is the mass of the entire piston assembly plus half of the piston rod mass divided by the projection area of ​​the support ring perpendicular to the piston rod axis at 120°, as shown in the following formula: P K = (M PA +M R / 2 ) / (0.866×D×Z ), where PK = specific pressure of the support ring, N / mm; M PA = Weight of piston assembly, N; M R = weight of piston rod, N; D = diameter of cylinder bore, mm; Z = axial length of support ring, mm; Formula P K = (M PA +M R / 2 ) / (0.866×D×Z ) is transformed into the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ); Under the condition of the same cylinder diameter, pressure, and valve size parameters, only the axial length of the support ring is a variable. Since the allowable specific pressure standard of the support ring of a lubricated horizontal cylinder is twice that of the support ring of a non-lubricated horizontal cylinder, according to the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ), the axial length Z value of the piston support ring of the oil-free lubrication unit is set to at least twice the axial length Z value of the piston support ring of the lubricating oil unit; There is no gap between the multiple piston rings and the bottom diameter of the ring groove, so that the piston ring has both sealing and supporting functions, and the total width composed of the widths H of the multiple piston rings is set to be at least greater than the axial length Z of the support ring, that is, n×H≥Z; Ultimately, the piston components of the same model, specification and parameters can be universally used in both oil- and oil-free working conditions.

[0015] The present invention has at least the following beneficial effects: The present invention analyzes the functions and design concepts of piston rings and support rings, innovatively designs a piston component, eliminates the gap between the bottom diameter of the piston ring and the bottom diameter of its ring groove, so that the piston ring has the function of a support ring in addition to the function of sealing the compressed medium pressure, thereby realizing universal design and application of piston components of the same model, same specification and same parameters under oil and oil-free conditions, and also realizes the universality of cylinder components of the same specification, improves the modularization and standardization level of the design, enhances the design efficiency, stabilizes the product quality, and enhances the reliability of the unit operation.

[0016] 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 study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing the correlation between the piston and cylinder compression chamber dimensions of the present invention; Figure 2This is a diagram showing the composition and size association of conventional piston components of the present invention; Figure 3 The oil-free lubricating piston components of the present invention are structured and dimensionally related.

[0018] Description of reference numerals: 1. Cylinder parts, 2. Piston parts, 3. Cylinder pressure packing, 4. Cylinder head, 5. Cylinder shaft end compression chamber, 6. Cylinder head end compression chamber, 7. Piston body, 8. Piston rod, 9. Piston nut, 10. Piston ring, 11. Support ring. DETAILED DESCRIPTION

[0019] In order to better understand the purpose, structure and function of the present invention, the present invention 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.

[0020] 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" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] like Figure 3 As shown, the present invention provides a piston component with a piston ring having both sealing and supporting ring functions, including a piston body and a supporting ring and a plurality of piston rings arranged on the piston body, wherein the piston body is provided with a plurality of ring grooves for respectively arranging the supporting ring and the plurality of piston rings, and there is no gap between the plurality of piston rings and the bottom diameters of the ring grooves, so that the piston ring has both sealing and supporting functions, and the supporting ring has a supporting function. The size of the piston ring is increased to completely fill the corresponding ring groove, or the size of the corresponding ring groove of the piston ring is reduced so that the corresponding piston ring completely fills the corresponding ring groove, thereby achieving no gap between the piston ring and the bottom diameter of the ring groove. The total width of the piston ring is n×H≥Z, wherein Z is the axial length of the supporting ring, H is the width of the piston ring, and n is the number of piston rings, all in mm.

[0022] By analyzing the functions and design concepts of piston rings and support rings, the gap between the bottom diameter of the piston ring and the bottom diameter of its ring groove is eliminated, so that the piston ring has the function of a support ring in addition to sealing the compressed medium. According to the requirements of API618 standard, comprehensive considerations are taken into account when designing piston components, and the total width of the piston ring is n×H≥Z, realizing the universal design of piston components with oil and oil-free working conditions of the same model, specification and parameters, improving the modularization and standardization level of the design, stabilizing product quality, and improving the reliability of compressor operation.

[0023] The design principle of the piston ring total width is based on the allowable specific pressure of the support ring specified in API618 standard. The specific design process is as follows: According to API618 standard, the permissible specific pressure standard of the support ring of a lubricated horizontal cylinder is twice the permissible specific pressure standard of the support ring of a non-lubricated horizontal cylinder; The specific pressure value is the mass of the entire piston assembly plus half of the piston rod mass divided by the projection area of ​​the support ring perpendicular to the piston rod axis at 120°, as shown in the following formula: P K = (M PA +M R / 2 ) / (0.866×D×Z ), where P K = specific pressure of the support ring, N / mm; M PA = Weight of piston assembly, N; M R = weight of piston rod, N; D = diameter of cylinder bore, mm; Z = axial length of support ring, mm; Formula P K = (M PA +M R / 2 ) / (0.866×D×Z ) is transformed into the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ); Under the condition of the same cylinder diameter, pressure, and valve size parameters, only the axial length of the support ring is a variable. Since the allowable specific pressure standard of the support ring of a lubricated horizontal cylinder is twice that of the support ring of a non-lubricated horizontal cylinder, according to the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ), the axial length Z value of the piston support ring of the oil-free lubrication unit is set to at least twice the axial length Z value of the piston support ring of the lubricating oil unit; There is no gap between the multiple piston rings and the bottom diameter of the ring groove, so that the piston ring has both sealing and supporting functions, and the total width composed of the widths H of the multiple piston rings is set to be at least greater than the axial length Z of the support ring, that is, n×H≥Z; Finally, the generalization of the piston components with the same model, the same specification, and the same parameters under the lubricated and non-lubricated conditions is realized.

[0024] It can be understood that the present invention is described by way of some embodiments. Those skilled in the art will appreciate 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 above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples herein.

Claims

1. A piston component having a piston ring having both sealing and supporting ring functions, characterized in that: It includes a piston body and a support ring and multiple piston rings arranged on the piston body. The piston body is provided with multiple ring grooves for respectively arranging the support ring and the multiple piston rings. There is no gap between the multiple piston rings and the bottom diameters of their ring grooves, so that the piston ring has both sealing and supporting functions, and the support ring has a supporting function.

2. The piston component having both sealing and supporting ring functions as claimed in claim 1, characterized in that: The size of the piston ring is increased to completely fill the corresponding ring groove, or the size of the corresponding ring groove of the piston ring is reduced so that the corresponding piston ring completely fills the corresponding ring groove, thereby achieving no gap between the piston ring and the bottom diameter of the ring groove.

3. The piston component having the piston ring having both the sealing and supporting ring functions as claimed in claim 1, characterized in that: The total width of the piston ring is n×H≥Z, where Z is the axial length of the support ring, H is the width of the piston ring, and n is the number of piston rings, all in mm.

4. The piston component having the piston ring having both the sealing and supporting ring functions as claimed in claim 3, characterized in that: The overall width of the piston ring is designed based on the allowable specific pressure of the support ring specified in API618 standard.

5. The piston component having the piston ring having both the sealing and supporting ring functions as claimed in claim 4, characterized in that: The specific design process is as follows: According to API618 standard, the permissible specific pressure standard of the support ring of a lubricated horizontal cylinder is twice the permissible specific pressure standard of the support ring of a non-lubricated horizontal cylinder; The specific pressure value is the mass of the entire piston assembly plus half of the piston rod mass divided by the projection area of ​​the support ring perpendicular to the piston rod axis at 120°, as shown in the following formula: P K = (M PA +M R / 2 ) / (0.866×D×Z ), where P K = specific pressure of the support ring, N / mm; M PA = Weight of piston assembly, N; M R = weight of piston rod, N; D = diameter of cylinder bore, mm; Z = axial length of support ring, mm; Formula P K = (M PA +M R / 2 ) / (0.866×D×Z ) is transformed into the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ); Under the condition of the same cylinder diameter, pressure, and valve size parameters, only the axial length of the support ring is a variable. Since the allowable specific pressure standard of the support ring of a lubricated horizontal cylinder is twice that of the support ring of a non-lubricated horizontal cylinder, according to the formula Z = (M PA +M R / 2 ) / (0.866×D×P K ), the axial length Z value of the piston support ring of the oil-free lubrication unit is set to at least twice the axial length Z value of the piston support ring of the lubricating oil unit; There is no gap between the multiple piston rings and the bottom diameter of the ring groove, so that the piston ring has both sealing and supporting functions, and the total width composed of the widths H of the multiple piston rings is set to be at least greater than the axial length Z of the support ring, that is, n×H≥Z; Ultimately, the piston components of the same model, specification and parameters can be universally used in both oil- and oil-free working conditions.

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