CN105604915A - Piston, compressor provided with same and machining method of piston - Google Patents

Abstract

The invention discloses a piston, which includes a piston body, wherein a groove is provided on the outer peripheral surface of the piston body, and the groove includes a first groove section and a second groove section, wherein the first groove The segment is located on one side of the first central plane of the piston body, the second groove segment is located on the other side of the first central plane, and the area of the second groove segment is larger than the area of the first groove segment ; Wherein, the first center plane is a plane passing through the axis of the piston body. Due to the different areas of the grooves on the outer peripheral surface on both sides of the piston body, there is a difference in the gas force generated by the gas pressure in the grooves on both sides, which can be used to offset the lateral component of the external force on the piston itself , so that the lateral friction of the piston can be reduced and the reliability of the piston can be improved. The invention also discloses a compressor and a processing method for the piston.

Description

A piston, a compressor having the same and a processing method for the piston

technical field

The invention relates to the technical field of piston compressors, in particular to a piston. The invention also relates to a compressor with the piston and a processing method for the piston.

Background technique

The core structure of a common piston compressor (such as a refrigerator piston compressor) is shown in Figures 1 and 2. The moving parts of the compressor are mainly composed of frame 1, piston 3, piston pin 2, crankshaft 5, and connecting rod 4. The schematic diagram of its mechanism is shown in Figure 3. In the working process, the piston 3 compresses the gas to do work under the action of the thrust F of the _{connecting rod} 4 . The thrust F on the _{connecting rod} on the piston can be decomposed into the force F of the compressed _gas and the lateral force F _lateral , while the reaction force F' on the crankshaft on the _{connecting rod} can be decomposed into the rotational resistance F _torque and the restraint force F _constraint . Among them, the presence of F _sideways causes one side of the piston to rub against the cylinder wall. At the same time, under the _lateral action of F, the piston will deviate from the center position, so the leakage on both sides of the piston is different, resulting in different gas pressures on both sides of the piston and causing additional lateral force, which further increases the total lateral force on the piston. Big.

For this reason, in the prior art, an eccentricity e is usually set between the center of the piston and the rotation center of the crankshaft to reduce the _lateral magnitude of the lateral component force F, but the effect is very limited. In addition, in the prior art, grooves are also provided on the outer peripheral surface of the piston body, such as a circle of grooves with a constant width as shown in Figure 4, so as to balance the pressure and reduce the contact area between the piston and the cylinder wall , thereby reducing friction, but the lateral force on the piston is still relatively large. Therefore, the piston structure of the prior art hinders further improvement of the performance of the compressor.

Contents of the invention

In view of the above-mentioned status quo of the prior art, the main purpose of the present invention is to provide a piston, which can reduce the lateral friction of the piston and improve the reliability of the piston.

Above-mentioned purpose realizes through following technical scheme:

A piston, which includes a piston body, wherein a groove is provided on the outer peripheral surface of the piston body, and the groove includes a first groove segment and a second groove segment, wherein the first groove segment is located on the piston body One side of the first central plane, the second slot section is located on the other side of the first central plane, and the area of the second slot section is larger than the area of the first slot section; wherein, the The first central plane is a plane passing through the axis of the piston body.

Preferably, the piston body is provided with a pin hole for connecting with the connecting rod, and the first central plane passes through the axis of the pin hole.

Preferably, the second groove segment is symmetrical with respect to the second central plane of the piston body, wherein the second central plane is a plane passing through the axis of the piston body and perpendicular to the first central plane.

Preferably, at least a portion of said second slot segment has a width greater than the width of said first slot segment.

Preferably, the second groove segment comprises a first portion coaxial with the piston body and a second portion non-coaxial with the piston body.

Preferably, said first slot segment is coaxial with a first portion of said second slot segment.

Preferably, the distance between the axis of the second portion of the second groove segment and the axis of the piston body is equal to the depth of the first groove segment.

Preferably, said second slot section is coaxial with said first slot section.

Preferably, both ends of the second slot section are located on the first central plane, and the width of the second slot section is equal everywhere.

Preferably, the piston body is a powder metallurgy part or a die-casting part.

Another object of the present invention is to provide a compressor comprising the aforementioned piston.

Yet another object of the present invention is to provide the aforementioned piston processing method, which includes the steps of:

rotating the piston body around its own axis, turning a part of the first groove segment and the second groove segment on the piston body;

The remainder of the second groove section is machined.

Preferably, when said second slot section comprises a first portion and a second portion which are not coaxial, the step of machining said remaining portion of the second slot section comprises:

offsetting the center of rotation of the piston body from its own axis toward the first groove segment, and turning the remaining portion;

When the second groove segment is coaxial with the first groove segment, the machining steps of the remaining part of the second groove segment include:

The piston body is rotated around its own axis, and the remaining part is milled.

In the piston of the present invention, due to the different areas of the grooves arranged on the outer peripheral surfaces on both sides of the piston body, the gas forces generated by the gas pressure in the grooves on both sides are different, and the difference between the gas forces on both sides can be used to offset the piston. The lateral force or part of the external force received by itself can reduce the lateral friction of the piston and improve the reliability of the piston. In particular, in the preferred solution of the present invention, the groove on the piston body includes a non-axial part, which can be processed twice through conventional turning and eccentric turning.

Description of drawings

Preferred embodiments of a piston, a compressor, and a piston processing method according to the present invention will be described below with reference to the accompanying drawings. In the picture:

Fig. 1 is a top view schematic diagram of a prior art piston compressor core structure;

Fig. 2 is a schematic cross-sectional view of the movement structure of Fig. 1;

Figure 3 is a schematic diagram of the mechanism of the piston compressor;

Fig. 4 is the schematic front view of the piston body of the prior art;

Fig. 5 is a schematic front view of a piston body in a preferred embodiment of the present invention;

Fig. 6 is a three-dimensional schematic diagram of the piston body of Fig. 5;

Fig. 7 is a schematic diagram of the force situation of the piston body in Fig. 5;

Fig. 8 is a schematic front view of another preferred embodiment of the piston body of the present invention;

Fig. 9 is a three-dimensional schematic diagram of the piston body of Fig. 8;

Figure 10 is a schematic diagram of traditional turning;

Figure 11 is a schematic diagram of eccentric turning.

detailed description

The present invention provides a piston in view of the aforementioned status of the prior art, which includes a piston body 6, referring to Figures 5-9, a groove is provided on the outer peripheral surface of the piston body 6, and the groove includes a first groove Segment 8 and second groove segment 9. Wherein, the first slot section 8 is located on one side of the first central plane of the piston body, and the second slot section 9 is located on the other side of the first central plane. In particular, the area of the second groove segment 9 is larger than the area of the first groove segment 8 . Here, the area of the groove section may refer to the area defined by the outer edge of the groove on the outer peripheral surface of the piston body, or may refer to the projected area of the groove on the first central plane. In the present invention, the first center plane is a plane passing through the axis of the piston body 6 .

That is, the grooves on the outer peripheral surface of the piston body of the present invention are asymmetrical grooves with respect to the first central plane, which is the primary difference between the present invention and the prior art pistons.

Since the area of the first groove section is different from that of the second groove section, and the gas pressure (here referred to as pressure) in the two groove sections is the same when the piston is working, the gas on the side of the larger groove section generates The gas force is also large, as shown in Figure 7, F2>F1, so by installing the piston correctly, the difference F2-F1 of the gas force on both sides can at least partially offset the external force on the piston (such as the connecting rod thrust F The _lateral component F of the _{connecting rod} ) helps to reduce the friction between the piston and the cylinder wall. Specifically, during installation, one side of the second groove segment can be placed on the side where the piston is closer to the cylinder wall, that is, the side that bears the _lateral force F, so that F2 can be opposite to the _lateral direction of F.

Usually, the piston body 6 is provided with a pin hole 7 for connecting with the connecting rod. In this case, the aforementioned first central plane also passes through the axis of the pin hole 7 . For example, in Figures 5 and 8, the first center plane coincides with the illustrated centerline. Therefore, when the aforementioned groove is provided on the piston body having a pin hole, the first groove segment and the second groove segment can be conveniently defined based on the pin hole. At the same time, it is also very easy to place one side of the second groove section on the side where the piston is closer to the cylinder wall during installation.

Preferably, the first groove segment 8 is in communication with the second groove segment 9 , especially the two can surround the outer peripheral surface of the piston body at 360 degrees, that is, form a full circle of grooves. Preferably, the two can meet at the position of the pin hole 7 , that is, the groove can pass through both ends of the pin hole 7 .

Preferably, the second groove segment 9 is symmetrical with respect to the second central plane of the piston body 6, wherein the second central plane passes through the axis of the piston body and is perpendicular to the first central plane plane, for example, in Figures 5 and 8, the second center plane coincides with the paper plane. Since the outer peripheral surface of the piston body 6 is, for example, a cylindrical surface, the direction of the gas force in the second groove section is different. When the second groove section is symmetrical about the second center plane, the gas force in the second groove section is symmetrical The resultant force direction of F is perpendicular to the first center plane, that is, perpendicular to the axis of the pin hole, thus just opposite to the _lateral direction of F, so it only plays the role of offsetting the _lateral direction of F, and does not cause the piston to deviate in other directions.

Preferably, the width of at least a part of the second groove segment 9 is greater than the width of the first groove segment 8 . In the present invention, the width of the groove segment refers to the size of the groove segment in the axial direction of the piston. For example, as shown in FIG. 5 , the width of the first slot segment is h, and the width of the second slot segment is H, wherein H>h. Or as shown in FIG. 8 , the width of only a part of the second groove segment is greater than the width of the first groove segment.

No matter whether the first groove section and the second groove section are connected or not, and whether they surround the piston body in a complete circle, the area of the groove section can be easily realized by setting the width of the groove section differently. In the case where the first groove section communicates with the second groove section, especially when the two surround the piston body for a full circle, as long as the second groove section has a part of the width greater than the width of the first groove section, it can be realized. difference in area. Preferably, the width of the first groove segment is constant, and the width of a part of the second groove segment may be the same as that of the first groove segment.

Obviously, the more H is greater than h, the more beneficial it is to reduce the aforementioned lateral force F _sideways , but the premise of using a larger H is that the contact area between the piston and the cylinder wall must be guaranteed to ensure sealing and contact stress. For example, when the length of the piston is 18-22 mm, generally, h can be 2-4 mm, and H can be 5-10 mm.

Preferably, as shown in FIGS. 5-7 , the second groove segment 9 includes a first portion 10 coaxial with the piston body 6 and a second portion 11 non-coaxial with the piston body 6 . That is to say, the second slot segment may include two parts with different axes, especially, the second part 11 is a part wider than the first slot segment. Here, whether the groove section is coaxial with the piston body refers to whether the cylindrical surface where the groove bottom of the groove section is located is coaxial with the outer peripheral surface of the piston body.

Since the second part of the second groove segment is not coaxial with the first part, but the first part is coaxial with the piston body, the depth of the second part is gradual, for example, preferably increases from 0 to the same depth as the first part. In this way, the second part can be processed by eccentric turning, which will be described in detail later.

Preferably, the first slot section 8 may be coaxial with the first portion 10 of the second slot section 9 . In this way, during specific processing, for example, the first groove segment 8 and the first portion 10 can be processed at one time, for example by conventional turning.

Two vertical centerlines are shown in Figure 5, wherein the longer centerline is the axis of the piston body, the first groove section, and the first part of the second groove section, and the shorter centerline is the second groove The axis of the second part of the segment.

Preferably, the eccentricity (that is, the distance between the axes) between the second part 11 of the second groove segment 9 and the piston body 6 (and also the first part or the first groove segment) is equal to the The depth of the first groove segment (preferably also the depth of the first part of the second groove segment).

Especially, when this eccentricity is equal to the depth of the first groove section, the groove bottom radius of the first part of the second groove section can be equal to the radius of the piston body, at this time, if the maximum depth of the second part is equal to the first groove section depth (preferably also the depth of the first part of the second groove segment), the two ends of the second part are roughly located at the position of the first central plane. That is to say, the length of the second groove segment is the longest and the width is equal everywhere, so as to maximize the difference in area from the first groove segment, thereby maximizing the characteristic of the piston in reducing lateral friction.

In addition, when the eccentricity is not equal to the depth of the first groove segment, according to the size of the eccentricity between the two parts of the second groove segment, by setting an appropriate groove bottom radius for the second part, the second part can also be made The two ends of the second part of the slot section are located approximately at the position of the first central plane, so that the length of the second slot section is the longest and the width is equal everywhere. However, in this case, the maximum depth of the second part may not be equal to the depth of the first part (or the first groove segment), and the calculation of the groove bottom radius of the second part will be relatively troublesome.

Alternatively, the second slot section may also be coaxial with the first slot section as a whole. That is, the wide part of the second groove section is also coaxial with the first groove section, so the groove bottom radius of the second groove section is equal everywhere, that is, the depth is also equal everywhere, equal to the depth of the first groove section, For example, as shown in Figures 8 and 9. Compared with the second groove section in the previous embodiment, which includes two parts with different axes, the second groove section in this embodiment is troublesome to process, for example, it cannot be completed on a lathe, but needs to be first A lathe is used to complete the turning of the first groove section and a part of the second groove section, and then use, for example, a milling machine to mill the part where the second groove section is wider than the first groove section. In this embodiment, the widened part of the second groove section may also extend to the position of the first central plane, that is, the width of the second groove section is equal everywhere, and the length reaches the longest.

Preferably, the piston body of the present invention can also be a powder metallurgy part or a die-casting part. That is, since the outer peripheral surface of the piston body is provided with grooves with different areas (asymmetric as a whole), the grooves can be manufactured at one time by powder metallurgy or die casting.

Alternatively, the groove on the piston body of the present invention can also be machined. Preferably, the processing method of the piston body may include the steps of:

(1) The piston body is rotated around its own axis, and a part of the first groove section and the second groove section are turned on the piston body. The turning process can adopt the traditional turning shown in FIG. 10 , that is, the piston body rotates, and its rotation center coincides with the axis of the piston body, and the turning tool 12 is fed to complete the turning.

(2) Machining the remainder of the second groove segment.

In particular, the above two steps can be performed in any order. That is, both the first groove section and a part of the second groove section can be processed first, and then the remaining part of the second groove section (that is, the part wider than the first groove section) can be processed, or the second groove section can be processed first. The widened part of the groove segment, and then process the corresponding part of the first groove segment and the second groove segment.

Preferably, when said second slot section comprises a first portion and a second portion which are not coaxial, the step of machining said remaining portion of the second slot section comprises:

The center of rotation of the piston body is offset from its own axis towards the first groove segment, and the remainder is machined by turning. That is, the center of rotation during turning can not coincide with the axis of the piston body, that is, eccentric turning as shown in Figure 11 (wherein the longer center line is the center of rotation, and the shorter center line is the axis of the piston body), And the center of rotation is deviated to one side of the first groove segment, and the turning tool 12 is fed to complete turning. Preferably, the plane formed by the center of rotation and the axis of the piston body should be perpendicular to the axis of the pin hole, so as to ensure the difference between the gas force (F2-F1) generated by the two groove segments of the groove and the lateral distribution of the thrust of the connecting rod. The force F _{lateral direction} is in the same plane and opposite in direction, so as to achieve the purpose of offsetting at least a part of the F _lateral direction during specific use.

When the above method is used to process the groove, due to the eccentric turning method, it is easy to realize the difference in the area of the groove sections on both sides of the piston, and the groove sections on both sides are connected, and the internal pressure (here refers to the pressure) is the same, so the area of the groove section is large The pressure generated by the gas on one side (here refers to the product of pressure and area) is also large.

Alternatively, when the second slot segment is coaxial with the first slot segment (that is, the widened portion of the second slot segment is also coaxial with the first slot segment), the remaining portion of the second slot segment Processing steps include:

The piston body is rotated around its own axis, and the remaining part is milled.

When the piston of the present invention is in use, the side with the larger groove section area is placed on the side closer to the piston and the cylinder (for example, due to the effect of the connecting rod thrust), the gas force generated on the side with the larger groove section area It is larger than the gas force generated on the side with a small area of the groove section, so as to offset or partially offset the lateral component of the thrust of the connecting rod, reduce the friction between the piston and the cylinder wall, and improve the reliability of the piston.

It should be noted that when the piston of the present invention is in use, the internal volume of the groove cannot communicate with the low pressure side inside the compressor, otherwise the aforementioned beneficial effects cannot be achieved.

Another aspect of the present invention provides a compressor comprising the aforementioned piston. The compressor of the present invention is, for example, a refrigerator piston compressor. Because the piston of the present invention can counteract part of the lateral force of the connecting rod thrust, the friction between the piston and the cylinder wall (that is, the lateral friction) is reduced, the reliability of the piston is improved, and the performance of the compressor is improved.

Those skilled in the art can easily understand that the above-mentioned measures can be freely combined and superimposed on the premise of no conflict.

It should be understood that the above-mentioned implementations are only exemplary rather than limiting, and those skilled in the art can make various obvious or equivalent solutions to the above-mentioned details without departing from the basic principles of the present invention. Any modification or replacement will be included in the scope of the claims of the present invention.

Claims (13)

1. a piston, it comprises piston only, it is characterized in that the outer peripheral face of described piston onlyBe provided with groove, described groove comprises the first groove section and the second groove section, wherein, and described the first groove sectionIn a side of the first median plane of piston only, described the second groove section is positioned at the another of described the first median planeOne side, and the area of described the second groove section is greater than the area of described the first groove section; Wherein, described inThe first median plane is the face through the axis of described piston only.

2. piston according to claim 1, is characterized in that, described piston only is provided with useIn the pin-and-hole being connected with connecting rod, described the first median plane is through the axis of described pin-and-hole.

3. piston according to claim 1 and 2, is characterized in that, described the second groove section aboutThe second median plane symmetry of described piston only, wherein, described the second median plane is the described piston of processThe axis of body the face vertical with described the first median plane.

4. according to the piston one of claim 1-3 Suo Shu, it is characterized in that, described the second groove sectionThe width of at least a portion is greater than the width of described the first groove section.

5. according to the piston one of claim 1-4 Suo Shu, it is characterized in that described the second groove section bagDraw together the Part I coaxial with described piston only and with described piston only out-of-alignment Part II.

6. piston according to claim 5, is characterized in that, described the first groove section and describedThe Part I of two groove sections is coaxial.

7. according to the piston described in claim 5 or 6, it is characterized in that of described the second groove sectionDistance between the axis of two parts and the axis of described piston only equals the dark of described the first groove sectionDegree.

8. according to the piston one of claim 1-4 Suo Shu, it is characterized in that, described the second groove section withDescribed the first groove section is coaxial.

9. according to the piston one of claim 1-8 Suo Shu, it is characterized in that, described the second groove sectionTwo ends are positioned at described the first median plane place, and the width of described the second groove section equates everywhere.

10. according to the piston one of claim 1-9 Suo Shu, it is characterized in that described piston onlyFor metallic sintered products or die casting part.

11. 1 kinds of compressors, is characterized in that, comprise according to the work one of claim 1-10 Suo ShuPlug.

12. according to the processing method of the piston one of claim 1-9 Suo Shu, it is characterized in that bagDraw together step:

Make the axis rotation of piston only around self, on piston only turning process the first groove section andA part for the second groove section;

Process the remainder of the second groove section.

13. processing methods according to claim 12, is characterized in that,

In the time that described the second groove section comprises out-of-alignment Part I and Part II, the institute of the second groove sectionThe procedure of processing of stating remainder comprises:

The pivot that makes piston only is from the axis of self towards described the first groove field offset, and turning addsWork goes out described remainder;

When described the second groove section is with described the first groove section when coaxial, the described remainder of the second groove sectionProcedure of processing comprises:

Make piston only around self axis rotation, Milling Process goes out described remainder.