JP2017008809A - Compressor - Google Patents

Abstract

To provide a hermetic compressor with improved exchangeability of a sliding portion with respect to a piston of a cylinder.
A compressor provided with a substantially cylindrical cylinder bush 50 which is provided inside a cylinder 5a having a substantially circular opening when viewed from the front, and which can be attached to the cylinder. Installed on.
[Selection] Figure 10

Description

The present invention relates to a compressor.

  Patent document 1 is known as a related technique. Patent document 1 is disclosing the friction material installed in the structure which can replace | exchange the inner wall of a cylinder bore. In addition, the outer peripheral surface of the friction material is bonded and fixed to the inner peripheral surface of the spring member (summary).

JP 2008-151106 A

  Since the friction material described in Patent Document 1 employs a spring member, the structure is complicated, and there is a possibility that the cost may increase or the possibility of breakage increases.

  The present invention made in view of the above problems is a compressor including a substantially cylindrical cylinder bush that is provided inside a cylinder having a substantially circular opening in a front view and is attachable to the cylinder. It is attached to the inside of the cylinder by press-fitting.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1. FIG. AA sectional drawing of FIG. FIG. 3 is an enlarged cross-sectional view of a main part of the compression chamber of Example 1. The principal part expanded sectional view of the compression chamber of Example 2. FIG. The perspective view explaining the cylinder bush shown in FIG. The principal part expanded sectional view of the compression chamber of Example 2. FIG. The perspective view explaining the cylinder bush shown in FIG. The expanded sectional view of another system of a rod. The relationship diagram of V2 / V1 and cylinder bush chamfering. The cylinder bush of Example 2 and the attachment figure of a cylinder. The expanded sectional view with a cylinder step of Example 2. FIG. The front view of a refrigerator.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Similar components are denoted by the same reference numerals, and the same description will not be repeated.

  1 is a longitudinal sectional view of a hermetic compressor 100 according to a first embodiment of the present invention, and FIG. 2 is a plan view of the hermetic compressor 100 of FIG.

  The hermetic compressor 100 houses an electric element 2 and a compression element 3 in a hermetic container 1.

  The electric element 2 has a stator 2a and a rotor 2b. A crankshaft 8 is attached to the rotor 2b. When electric power is supplied to rotate the rotor 2b, this rotational force is transmitted and the crankshaft 8 rotates. The crankshaft 8 has a main shaft 8a and an eccentric shaft 8b on the upper portion of the main shaft 8a capable of eccentric rotational movement about the main shaft 8a.

  The compression element 3 has a cylinder block 5 made of, for example, cast iron or an iron-based material. The cylinder block 5 is formed with a cylinder 5a, a frame portion 5b, and a bearing portion 5c. The compression element 3 is elastically supported by the bottom part of the airtight container 1 with the coil spring through the stator 2a fixed to the lower part of the flame | frame part 5b. A balance weight 9 is provided between the cylinder 5a and the eccentric shaft 8b, and a gap communicating with the vicinity of the opening of the compression chamber 12 is located between the cylinder 5a and the balance weight 9.

  The hermetic compressor 100 is a so-called reciprocating type in which the piston 7 reciprocates in one end side of a substantially cylindrical cylinder bush 50 fixed to the cylinder 5a by, for example, press-fitting. One end of the rod 6 which is a connecting means is connected to the eccentric shaft 8 b and the other end is connected to the piston 7. The rod 6 has a large-end bearing portion that is fitted to the cylindrical eccentric shaft 8 b and a ball joint portion that is fitted to the piston 7. A known piston pin may be used for attachment to the piston 7.

  The eccentric rotational force of the eccentric shaft 8 b is converted by the rod 6 into the reciprocating power of the piston 7 and transmitted. As a result, the piston 7 reciprocates in the bore of the cylinder bush 50. The piston 7 can be loosely fitted to the cylinder bush 50 with a predetermined gap, for example, a gap dimension of about 10 μm due to a difference in diameter.

  The other end side of the cylinder bush 50 is closed by a cylinder head 10 in which a suction valve and a discharge valve (not shown) are incorporated. The cylinder head 10, the cylinder bush 50 and the piston 7 constitute a compression chamber 12. Yes. In the compression chamber 12, the suction valve and the discharge valve are opened and closed in synchronization with the reciprocating motion of the piston 7. The refrigerant is sequentially sucked into the compression chamber 12 and compressed as the piston 7 approaches the cylinder head 10. The compressed refrigerant is discharged from the discharge valve.

  Note that the lubricating oil 4 stored at the bottom of the sealed container 1 is pulled up by the centrifugal pump action of the oil pump 8 c attached to the lower end of the crankshaft 8 by the rotation of the crankshaft 8. The lubricating oil 4 is guided upward through a spiral groove 8d formed on the outer periphery of the main shaft 8a. A part of the lubricating oil 4 lubricates the large end bearing part and the ball joint part, and the other part is injected to the periphery from a lubricating oil radiation hole 8bb provided in the upper end part of the eccentric shaft 8b. Lubrication and sealing between the piston 7 and the cylinder bush 50 are mainly performed by the injected lubricating oil 4.

  The refrigerant flows into the sealed container 1 through the suction pipe 16 communicating with the inside and outside of the sealed container 1. Thereafter, the refrigerant passes through the plastic suction silencer 17 and enters the compression chamber 12 of the cylinder 5a. The refrigerant thus compressed is discharged from the cylinder head 10 into the discharge chamber in the head cover 11, passes through the discharge silencer 18, and passes through the discharge pipe 20 through the discharge pipe 19. Thereby, it flows out to the refrigerating cycle outside the airtight container 1.

FIG. 3 is an enlarged cross-sectional view of a main part of the compression chamber of the first embodiment. The cylinder bush 50 can be formed of, for example, a carbon material. Since the carbon material has a layered crystal structure and is self-lubricating, adhesion can be suppressed and sliding noise can be reduced. The dynamic friction coefficient of the carbon material is about 0.1 to 0.2, which is lower than the dynamic friction coefficient 0.3 to 0.5 of cast iron or iron-based material. In addition, the linear expansion coefficient of the carbon material is about 5 × 10 ⁻⁶ / K, which is lower than the linear expansion coefficient of cast iron or iron-based material, 12 × 10 ⁻⁶ / K. The amount can be suppressed. That is, since the change of the gap dimension between the piston 7 and the cylinder bush 50 is suppressed, the gap dimension at room temperature can be reduced, for example.

When the cylinder bush is formed as in this embodiment, the diameter gap dimension δ and the piston diameter φD between the piston 7 and the cylinder bush 50 are set to 3.8 × 10 ⁻⁵ ≦ δ / φD ≦ 3.8 × 10 ⁻⁴ . It becomes possible. From the viewpoint of the relationship between sliding loss and leakage loss, the compressor efficiency can be improved.

  The configuration of the second embodiment can be the same as that of the first embodiment except for the following points. FIG. 4 is an enlarged cross-sectional view of a main part of the compression chamber of the second embodiment. The cylinder bush 50 of the present embodiment is a wound bush obtained by rounding a copper-based baked bonded metal layer 50a inside a metal plate 50b. Since the copper-based sintered metal layer 50a is excellent in lubricity and wear resistance, the performance of the hermetic compressor 100 can be improved.

  FIG. 5 is an explanatory view for explaining a method of manufacturing the cylinder bush 50. The cylinder bush 50 is formed by winding a metal plate 50b having a copper-based sintered metal layer 50a on the surface so that the copper-based sintered metal layer 50a is on the inside.

  As shown in FIGS. 6 and 7, the cylinder bush 50 may employ a surface layer 50c impregnated with a PTFE resin instead of the copper-based sintered metal layer 50a. The surface layer 50c sliding on the piston 7 preferably includes a porous sintered layer 50e including bronze powder 50f on the metal plate 50b side. In this case, the cylinder bush 50 includes a metal plate 50b, a bronze powder porous sintered layer 50e, and a PTFE resin layer 50d in order from the outermost layer.

  The PTFE-based resin layer 50d has a lower coefficient of friction than the copper-based sintered metal layer 50a, and can reduce sliding loss. Moreover, abrasion resistance improves by providing the porous sintered layer 50e provided with the bronze powder 50f. In other words, the efficiency and reliability of the hermetic compressor 100 can be improved by using the material characteristics of the composite layers of different materials.

  Further, regarding the manufacturing method of the cylinder block 5 incorporating the cylinder bush 50, after the cylinder bush 50 is assembled to the cylinder block 5 by press fitting, shrink fitting or the like in the final process of the cylinder block 5 with a large number of machining steps, The inner diameter is polished and the mounting surface of the cylinder head 10 is ground. Here, even when the inner diameter dimension of the cylinder bush 50 is processed to be large and the clearance dimension value with the piston 7 is not managed, only the cylinder bush 50 is replaced, and the cylinder block 5 is lost by machining again. I don't have to. That is, the cylinder block 5 can be reused, and a resource-saving and inexpensive hermetic compressor can be provided.

  Further, if a chamfer or R shape for removing burrs and burrs generated during inner diameter processing is provided at the upper end of the inner diameter of the cylinder bush 50 on the cylinder head 10 side (top dead center side), an uncompressed space is generated in the compression chamber. . In general, it is considered that when the non-compressed space is increased, volumetric efficiency and compressor efficiency are reduced. Specifically, in the non-compression space, it is considered that the refrigerant gas that is not discharged from the compression chamber when the piston 7 reaches the top dead center is expanded by a so-called adiabatic change in the next suction process. ) Expansion so that x (volume) / (temperature) = constant. At this time, considering use in a refrigeration cycle such as a refrigerator, as an example, the pressure is about 20 times the maximum operating compression ratio of the compressor, and the temperature change is the absolute temperature ratio, 100 ° C. (370 K) → −20 Assuming that the temperature is about 2/3 times in the case of the temperature (250 K), the volume change is the reciprocal of this, so it is assumed that it is about 13 times. That is, it means that the refrigerant that has not been discharged expands and inhibits the intake of new refrigerant. Therefore, a C chamfer or R shape is provided at the upper end of the inner diameter of the cylinder bush 50 on the cylinder head 10 side (top dead center side) and By setting the ratio V2 / V1 of the compression chamber volume V1 to at most 1%, it is possible to prevent a decrease in volume efficiency and a decrease in compressor efficiency. Alternatively, a method of suppressing the increase in the non-compressed volume V2 by performing corner processing within C0.1 or R0.1 regardless of the ratio may be used.

  As a method for reducing the above-described non-compression space, the cylinder bush 50 is mounted on the cylinder and then the cylinder head 10 mounting surface (surface on the top dead center side) is processed to increase the height of the end surface of the cylinder bush 50. The height can be substantially matched with the mounting surface of the cylinder head 10, and the sealing performance with the cylinder head 10 can be improved.

  FIG. 10 shows a schematic diagram of the method of assembling the cylinder 5 and the cylinder bushing 50 according to this embodiment, and the assembling method will be described. When the cylinder bush 50 is assembled to the cylinder 5, breakage of the outer peripheral end surface of the cylinder bush 50 or strain deformation may occur in the cylinder bush 50. For example, assembling is facilitated by providing the chamfer 51 on the outer peripheral side of the end face of the cylinder bush 50 or the inner diameter side of the cylinder 5. Further, according to the chamfer 51, when the piston load is locally applied to the cylinder bush during operation, the cylinder bush 50 can be deformed relatively freely, so that the local surface pressure can be reduced and the reliability can be improved. The chamfer 51 may be provided on either the rod 6 side or the head cover 11 side.

  FIG. 11 shows an enlarged cross-sectional view of the cylinder step 5d. The cylinder stepped portion 5d is a portion protruding to the inner diameter of the cylinder 5 so as to narrow the inner diameter of the cylinder 5, and suppresses the cylinder bush 50 from moving in the reciprocating direction of the piston 7. The cylinder step 5 d is provided on the rod 6 side with respect to the cylinder 5. The cylinder bush 50 is closed at the top dead center side by a cylinder head. During operation, the cylinder bush 50 tends to move toward the bottom dead center from the pressure difference between the compression chamber 12 and the sealed container 1 and the piston 7. Take the load. For this reason, by providing the cylinder stepped 5d, the cylinder bush 50 does not move beyond the stepped position, and a highly reliable hermetic compressor can be provided. Further, when the cylinder bushing 50 is assembled to the cylinder 5, the cylinder step is positioned to position the cylinder bushing 50, so that the assembly dimension management of the bushing 50 is facilitated, and an inexpensive hermetic compressor can be provided.

  In order to manage the assembly position of the cylinder bush 50 by the cylinder step 5d or in the same manner, a projection may be provided in the cylinder bush 50 assembly hole of the cylinder block 5 to manage the assembly dimensions. Specifically, the stopper may be formed by forming a stepped annular shape having a diameter smaller than the outer diameter of the cylinder bush 50 or having a single or plural protrusions. If it is an annular shape, the pressure applied to the cylinder bush 50 can be reduced, so that damage can be suppressed. If it is a protrusion, it is easy to attach or remove the cylinder bush 50 using a jig from a portion other than the protrusion. . The cylinder stepped 5d may be a substantially annular shape having a gap extending substantially 0 ° out of the annular shape. In this case, the cylinder bush 50 can be easily attached and detached using, for example, a needle-shaped jig through the gap.

  In the case where the cylinder stepped 5d is formed in a protruding shape, it is preferable that the annular joint 52 of the cylinder bush 50 is provided at a position where it can be prevented from contacting the cylinder stepped 5d. For example, in a front view of the cylinder 5 (observation from the axial direction), a straight line passing through the axis of the cylinder bush 50 and the cylinder stepped portion 5d and a straight line passing through the axis of the cylinder bush 50 and the annular joint 52 are formed. The angle is preferably 30 ° or more or 45 ° or more.

  In the replacement operation of the cylinder bush 50, the cylinder bush 50 may be inserted using the means which is inserted into the inner diameter side of the cylinder bush 50 and the surface of the jig expands and comes into close contact with the outer diameter side. The diameter or height of the stepped shape portion shown in the cylinder stepped portion 5d may be provided with a portion that is lower than the inner diameter of the cylinder bushing, and the end of the cylinder bushing 50 may be pushed out.

  The cylinder stepped portion 5d or the stopper described above is preferably attached at a position where contact with the end of the cylinder bush 50 created by rounding (a cut portion extending in the axial direction in FIG. 7) can be suppressed. For example, it is preferable that the stopper is formed of a protrusion and the end of the cylinder bush 50 is provided at an angle of 45 ° or 60 ° or more, or approximately 90 ° or approximately 180 ° or more with respect to the protrusion.

  The compressor 100 of the present invention can be employed in various known devices such as the refrigerator 200 illustrated in FIG.

1 Airtight container
2 Electric elements
2a Stator
2b rotor
3 compression elements
4 Lubricating oil
5 Cylinder block
5a cylinder
5b Frame part
5c Bearing part
5d Stepped 6 rod (Connecting rod)
6a Rod (Scotch yoke)
7 Piston
8 Crankshaft
8a spindle
8b Eccentric shaft
8bb Lubricating oil radiation hole
8c Oil pump
8d Spiral groove 9 Balance weight
10 Cylinder head
11 Head cover
12 Compression chamber
16 Suction pipe
17 Suction silencer
18 Discharge silencer
19 Discharge pipe
20 Discharge pipe
30 Refueling hole
50 Cylinder bush 50a Copper-based sintered metal layer 50b Metal plate 50c Surface layer impregnated with PTFE-based resin 50d PTFE-based resin layer 50e Bronze sintered layer 50f Bronze powder 100 Sealed compressor 200 Refrigerator

Claims (5)

A compressor provided with a substantially cylindrical cylinder bush that is provided inside a cylinder having a substantially circular opening in a front view and is attachable to the cylinder,
The compressor, wherein the cylinder bush is attached to the inside of the cylinder by press-fitting. A cylinder head provided on one end of the cylinder;
Having a step provided on the other end side of the cylinder,
2. The step according to claim 1, wherein the inner dimension of any part on the other end side of the cylinder is smaller than the outer diameter or the inner diameter of the cylinder bush when the cylinder is viewed from the front. Compressor. The cylinder bush manufactured including a step of winding a plate-shaped member has an annular seam,
The step is a protrusion,
In the front view of the cylinder, an angle formed by a straight line passing through the axis of the cylinder bush and the stepped portion and a straight line passing through the axis of the cylinder bush and the annular joint is 30 ° or more. The compressor according to claim 2.   The compressor according to any one of claims 1 to 3, wherein the cylinder bush has a chamfered shape on an outer peripheral end surface. The cylinder bush includes a cylindrical sintered metal plate having a porous sintered layer made of bronze powder having lubricity and wear resistance and a surface layer impregnated with a PTFE resin inside.
A piston that reciprocates inside the cylinder bush,
When the diameter gap dimension of the piston and the cylinder bush is δ and the diameter of the piston is φD, δ / φD is in the range of 3.8 × 10 ⁻⁵ ≦ δ / φD ≦ 3.8 × 10 ^−4. The compressor according to any one of claims 1 to 4, wherein the compressor is characterized by the above.

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