JP2007132259A - Hermetic compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep deformation of a compression chamber and an auxiliary bearing small, improving reliability and efficiency of a compressor by keeping fastening torque of bolt fixing the auxiliary bearing low. <P>SOLUTION: In a hermetic compressor, friction coefficient in a piston reciprocating direction can be kept high, fastening torque of a bolt 131 can be kept relatively low, and deformation of the compression chamber 123a can be kept small by forming a wave shape mark on one of a surface of abutting block 123 or a surface of abutting auxiliary bearing 132. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hermetic compressor mainly used for a household refrigerator.

  Conventionally, there is a secondary bearing mounting surface for fixing a secondary bearing to a block of a hermetic compressor, which is a surface obtained by lapping or grinding (see, for example, Patent Document 1).

  Hereinafter, a conventional hermetic compressor will be described with reference to the drawings.

  7 is a longitudinal sectional view of a conventional hermetic compressor, FIG. 8 is a top plan view of a hermetic container of the conventional hermetic compressor, and FIG. 9 is a perspective view of a main part of the conventional hermetic compressor. .

  7, 8, and 9, the airtight container 1 is filled with the refrigerant 2 and the refrigerating machine oil 3 is stored.

  The electric element 11 includes a stator 12 connected to an external power source (not shown), and a rotor 13 arranged with a predetermined gap from the inside of the stator 12.

  The compression element 21 is fixed above the stator 12 and the shaft 22 having the eccentric shaft portion 22b and the auxiliary shaft portion 22c and the main shaft portion 22a that are coaxially provided above and below the eccentric shaft portion, and the compression chamber 23a. , A main bearing 24 that is provided on the block 23 and supports the main shaft portion 22a, a sub bearing 32 that supports the sub shaft portion 22c fixed to the block 23, and a reciprocating motion in the compression chamber 23a. And a connecting means 26 for connecting the piston 25 and the eccentric shaft portion 22b to form a reciprocating compression mechanism.

  The auxiliary bearing 32 abuts the surfaces perpendicular to the axis of the shaft 22 and is fixed to the block 23 with bolts 31.

  The operation of the hermetic compressor configured as described above will be described below.

  When the stator 12 is energized from an external power source, the rotor 13 rotates with the shaft 22. Accordingly, the eccentric movement of the eccentric shaft portion 22b causes the piston 25 to reciprocate in the compression chamber 23a via the connecting means 26 to perform a predetermined compression operation for compressing the suction gas.

The main bearing 24 and the sub-bearing 32 pivotally support a compression load that acts on the eccentric shaft portion 22b from the piston 25 via the connecting means 26.
Japanese Utility Model Publication No. 53-11710

  However, in the conventional configuration described above, in order to increase the flatness of the abutting surfaces of the block 23 and the sub-bearing 32, both abutting surfaces are lapped or ground. Therefore, the surface roughness of the abutting surface is small and the friction coefficient is small, and the bolts are tightened with a high tightening torque so that no slippage occurs even if the secondary bearing 32 receives the reaction force of the compression load resulting from the compression operation of the piston 25. It is necessary to tighten 31.

  However, it has been found that particularly when the fastening portion of the bolt 31 is provided in the vicinity of the compression chamber 23a of the block 23, a large distortion is partially generated inside the compression chamber 23a by the tightening force of the bolt 31. This has been found from the fact that even if the clearance between the piston 25 and the compression chamber 23a is controlled to a predetermined value before tightening the bolt, a contact mark is generated at a specific portion of the piston 25 and the compression chamber 23a. .

  Therefore, the clearance between the piston 25 and the compression chamber 23a has to be increased by an excessive amount of distortion. As a result, the overall clearance is widened, the refrigerant gas leaks and the efficiency is deteriorated. Further, since the distortion of the compression chamber 23a adversely affects the sliding of the piston 25, the reliability is also impaired.

  Even if the fastening portion of the bolt 31 is not provided in the vicinity of the compression chamber 23a of the block 23, the secondary bearing 32 is distorted by the fastening force of the bolt 31, and the high efficiency and high reliability are similarly lost. End up.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a highly reliable and highly efficient hermetic compressor.

  In order to solve the above-described conventional problems, the hermetic compressor according to the present invention is formed by forming a wavy mark on one of the surfaces where the block and the auxiliary bearing abut, and the piston on the surface where the block and the auxiliary bearing abut. Since the coefficient of friction in the reciprocating motion direction increases, the tightening torque of the bolt for fixing the auxiliary bearing can be reduced.

  The hermetic compressor of the present invention can reduce the tightening torque of the bolt for fixing the sub-bearing, so that the distortion of the compression chamber and the sub-bearing can be kept small. Can be provided.

  According to the first aspect of the present invention, lubricating oil is stored in a sealed container and an electric element and a compression element driven by the electric element are accommodated. The compression element sandwiches the eccentric shaft portion and the eccentric shaft portion. A shaft having a sub-shaft portion and a main shaft portion provided coaxially in the vertical direction, a block having a compression chamber, a main bearing provided in the block and supporting the main shaft portion, and fixed to the block A secondary bearing that pivotally supports the secondary shaft portion; a piston that reciprocates in the compression chamber; and a connecting means that connects the piston and the eccentric shaft portion, wherein the secondary bearing is an axis of the shaft. The surface perpendicular to each other is fixed to the block with bolts, and wavy marks are formed on either the surface of the block that contacts or the surface of the auxiliary bearing that contacts, The secondary bearing Since the friction coefficient of the abutting surface in the reciprocating direction of the piston is increased, the tightening torque of the bolt for fixing the auxiliary bearing can be reduced, and the distortion of the compression chamber and the auxiliary bearing can be reduced. A highly reliable and highly efficient hermetic compressor can be provided.

  According to a second aspect of the present invention, in addition to the first aspect of the present invention, the wavy trace is formed in a direction perpendicular to the reciprocating motion direction of the piston, and the surface of the surface where the block and the sub-bearing contact each other. The friction coefficient in the reciprocating direction of the piston is maximized, so that the tightening torque of the bolt for fixing the auxiliary bearing can be further reduced, and the distortion of the compression chamber and the auxiliary bearing can be reduced. In addition to the effects of the invention, a highly reliable and highly efficient hermetic compressor can be provided.

  In addition to the invention of claim 1 or 2, the invention of claim 3 is formed by forming wavy marks by cutting, and at the same time when machining the contact surface of the block or the auxiliary bearing. Since it can be formed, it is not necessary to add a special process, so that productivity can be further improved in addition to the effects of the invention described in claim 1 or claim 2.

  In addition to the invention described in claim 3, the invention described in claim 4 has a wavy mark formed in an arc shape and can be processed by a general-purpose processing machine such as a milling machine. Since there is no need to do this, in addition to the effect of the invention of claim 3, the facility cost can be further reduced.

  According to a fifth aspect of the present invention, in addition to the first aspect of the present invention, the block and the auxiliary bearing are made of cast iron, and are in contact with each other. Since the same kind of metal is used, the friction coefficient in the reciprocating direction of the piston on the surface where the block and the sub-bearing come into contact with each other is further increased due to the adhesion effect, so that the tightening torque of the bolt for fixing the sub-bearing is further increased. In addition to the effects of the invention according to any one of claims 1 to 4, in addition to the effects of the invention according to any one of claims 1 to 4, it is possible to reduce the distortion of the compression chamber and the sub-bearing. Machine can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
1 is a longitudinal sectional view of a hermetic compressor according to the first embodiment of the present invention, FIG. 2 is a top plan view of the hermetic compressor according to the first embodiment, and FIG. 3 is a hermetic compression according to the same embodiment. 4 is an enlarged view of the main part of the block of the hermetic compressor according to the embodiment, FIG. 5 is a cross-sectional view of the main part of the block of the hermetic compressor according to the same embodiment, and FIG. The processing drawing of the block of the hermetic compressor in the embodiment is shown.

  1 to 6, the airtight container 101 is filled with the refrigerant 102 and the refrigerating machine oil 103 is stored. Here, the refrigerant 102 is R600a which is a hydrocarbon refrigerant, and the refrigerating machine oil 103 is compatible with the refrigerant 102, for example, synthetic oil, mineral oil, or polyol ester oil.

  The electric element 111 includes a stator 112 connected to an external power source (not shown), and a rotor 113 arranged with a predetermined gap from the inside of the stator 112.

  The compression element 121 is fixed above the stator 112 and the shaft 122 having the auxiliary shaft portion 122c and the main shaft portion 122a that are coaxially provided above and below the eccentric shaft portion 122b and the eccentric shaft portion, and the compression chamber 123a. A cast iron block 123 that forms a shaft, a main bearing 124 that is provided on the block 123 and supports the main shaft portion 122a, a cast iron sub bearing 132 that is fixed to the block 123 and supports the sub shaft portion 122c, and a compression chamber A reciprocating compression mechanism is formed by including a piston 125 that reciprocates within 123a and a connecting means 126 that connects the piston 125 and the eccentric shaft portion 122b.

  The auxiliary bearing 132 has a surface 132a that contacts the block 123 finished by polishing, and is processed at a right angle to the surface 132a that the hole that supports the auxiliary shaft portion 122c contacts with respect to the contacting surface 132a. ing.

  On the other hand, wavy marks 141 are formed on the plurality of surfaces 123b with which the sub bearings 132 provided on the block 123 abut in a direction perpendicular to the reciprocating direction of the piston 125.

  The wavy trace 141 is formed by cutting with a milling machine. Triangular peaks and troughs appear continuously in the radial direction of the milling cutter 151, and each triangular peak and trough of the milling cutter 151. It is continuously formed coaxially with the shaft center. Specifically, the difference between the peak of the mountain and the bottom of the valley is 50 μm, and the pitch of the peak of the mountain is 50 μm.

  When the surface roughness is Rmax 5 μm or less, the coefficient of friction is small, and when Rmax is 100 μm or more, the abutting surface 123b is difficult to be machined perpendicular to the axis of the shaft 122. The surface roughness Rmax is preferably in the range of 5 μm to 100 μm.

  The auxiliary bearing 132 and the block 123 abut on the abutting surface 132 a and the abutting surface 123 b and are fixed by the bolt 131. The bolt 131 is M5, and the compression load supported by the auxiliary bearing 132 in the case of a hermetic compressor using R600a as the refrigerant 102 is about 980 N, and the tightening torque is changed from the conventional 980 N · cm to 490 N · cm. It has dropped in half.

  The operation of the hermetic compressor configured as described above will be described below.

  When the stator 112 is energized from an external power source, the rotor 113 rotates with the shaft 122. Accordingly, the eccentric movement of the eccentric shaft portion 122b causes the piston 125 to reciprocate in the compression chamber 123a via the connecting means 126 to perform a predetermined compression operation for compressing the suction gas.

  The main bearing 124 and the sub-bearing 132 pivotally support the reaction force of the compression load that acts on the eccentric shaft portion 122b from the piston 125 through the connecting means 126.

  The compressive load acting on the secondary bearing 132 is supported by the frictional force in the reciprocating direction of the piston 125 on the surface where the block 123 and the secondary bearing 132 abut, and the frictional force is greater than the load acting on the secondary bearing 132. When the secondary bearing 132 is not displaced, the main bearing 124 and the secondary bearing 132 remain coaxial.

  In the present embodiment, the friction coefficient in the reciprocating direction of the piston 125 on the surface where the block 123 and the auxiliary bearing 132 abut is increased by the wavy trace 141, and as a result, the tightening torque of the bolt 131 is reduced from the conventional 980 N · cm. The sub-bearing 132 did not shift due to the compressive load despite being halved to 490 N · cm.

  On the other hand, by reducing the tightening torque to half that of the prior art, almost no distortion occurs inside the compression chamber 123a, and by narrowing the clearance between the piston 25 and the compression chamber 23a by 2.5 μm from the conventional clearance, The compressor performance was improved by about 3%, and the efficiency was improved by about 1.5%.

  Moreover, even if an operation test or a severe test was performed, contact marks did not occur at specific locations of the piston 125 and the compression chamber 123a.

  As described above, since the distortion of the compression chamber 123a and the sub-bearing 132 can be suppressed, a highly reliable and highly efficient hermetic compressor can be provided.

  In the present embodiment, the wavy trace 141 is cut by a milling machine, and triangular peaks and valleys appear continuously in the radial direction of the milling cutter 151, and each triangular peak and valley is Although an example in which the milling cutter 151 is continuously formed coaxially with the axial center of the milling cutter 151 is illustrated, the same operation and effect can be obtained even if triangular crests and valleys are continuously formed linearly using, for example, a cylindrical grinding machine. .

  Further, in the present embodiment, the surface 132a that contacts the block 123 of the sub-bearing 132 is illustrated as being finished by polishing, but is perpendicular to the wavy trace 141 provided on the surface 123b that contacts the block 123. That is, by providing the same wavy marks as the block 123 in parallel with the reciprocating direction of the piston 125, when the bolt 131 is tightened, the wavy marks are engaged with each other at a right angle, and a higher frictional force can be obtained. Therefore, it is particularly effective when a higher compressive load is generated, for example, when a high-pressure refrigerant such as R290 (propane) or R404a is used as the refrigerant.

  As described above, since the hermetic compressor according to the present invention can be provided with a highly efficient and reliable one, the hermetic compressor used in a refrigeration cycle apparatus such as an air conditioner or a vending machine. It can also be applied to machines.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. Top plan view of hermetic compressor in the same embodiment The principal part perspective view of the hermetic compressor in the embodiment The principal part enlarged view of the block of the hermetic compressor in the embodiment Sectional drawing of the principal part of the block of the hermetic compressor in the same embodiment Processing drawing of block of hermetic compressor in the same embodiment Vertical section of a conventional hermetic compressor Top plan view of a sealed container of a conventional hermetic compressor Main part perspective view of a conventional hermetic compressor

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Airtight container 103 Lubricating oil 111 Electric element 121 Compression element 122 Shaft 122a Main shaft part 122b Eccentric shaft part 122c Sub shaft part 123 Block 123a Compression chamber 124 Main bearing 125 Piston 126 Connecting means 131 Bolt 132 Sub bearing 141 Wave-like trace

Claims (5)

  Lubricating oil is stored in a sealed container and an electric element and a compression element driven by the electric element are accommodated, and the compression element is provided with an eccentric shaft portion and a countershaft provided coaxially vertically with the eccentric shaft portion interposed therebetween. A shaft having a portion and a main shaft portion, a block having a compression chamber, a main bearing provided in the block for supporting the main shaft portion, and a sub shaft supporting the auxiliary shaft portion fixed to the block A bearing, a piston that reciprocates in the compression chamber, and a coupling means that couples the piston and the eccentric shaft portion, wherein the auxiliary bearing abuts surfaces perpendicular to the shaft center of the shaft, and A hermetic compressor in which a wavy mark is formed on at least one of the surface of the abutting block or the abutting sub-bearing surface while being fixed to the block with a bolt.   The hermetic compressor according to claim 1, wherein the wavy trace is formed in a direction perpendicular to a reciprocating direction of the piston.   The hermetic compressor according to claim 1, wherein the wavy trace is formed by cutting.   The hermetic compressor according to claim 3, wherein the wavy trace is formed in an arc shape.   The hermetic compressor according to any one of claims 1 to 4, wherein the block and the auxiliary bearing are made of cast iron.

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