JP2005133657A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auxiliary bearing structure with high reliability capable of giving elasticity to the auxiliary bearing structure, relaxing half contact of a crank shaft with an inner periphery of the bearing caused by flexure of an assembly structure and the crank shaft, and reducing a sliding surface pressure without using a conventional spherical surface bearing which requires extraordinary cost increase but using a sliding bearing of which material cost and machining cost are low. <P>SOLUTION: An elastic portion is provided at a flange portion of a housing which presses in and retains a bearing bush to make the auxiliary bearing follow inclination of the axis core of the crank shaft. Besides, the winding bush having a bronze powder porous sintered layer is also used. This surface layer is plastic deformable and the sliding surface is formed in a working form during work operation to reduce the sliding surface pressure and to increase sliding reliability. Besides, a carbon bearing is used to prevent seizure due to missing of an oil film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bearing for a rotary compressor such as a scroll compressor.

  As a conventional scroll compressor, there is JP-A-6-173877 (referred to as Patent Document 1).

  FIG. 8 is a longitudinal sectional view showing an example of a conventional scroll compressor.

  According to this conventionally known example, the posture of the crankshaft 26 can be freely changed in the auxiliary bearing 29 by the automatic alignment function. Therefore, the inclination of the crankshaft 26 during assembly and the sealing of the auxiliary bearing support frame 33 are sealed. The inclination at the time of attaching the container 21 can be absorbed, and the assemblability can be improved. Similarly, there is an effect that the deflection of the crankshaft 26 during operation is absorbed and the sliding reliability of the auxiliary bearing is improved by preventing one-sided contact.

  Further, in the known technique, for example, the spherical bearing 29a is formed by heat treatment such as carbon steel for mechanical structure, heat treatment is performed, and after forming a nitriding layer, surface treatment such as molybdenum disulfide coating or manganese phosphate treatment is performed (see FIG. In some cases, the sliding reliability of the auxiliary bearing 29 may be further improved.

  However, the conventionally known scroll compressor using the spherical bearing described above is extremely excellent in assemblability and sliding reliability, but requires high precision grinding and complicated and sophisticated surface treatment of the spherical bearing, In addition, many processes are required, such as cutting and grinding of the inner spherical surface of the housing. As a result, the construction of the secondary bearing requires a large amount of money and equipment, and the manufacturing cost of the compressor Had the disadvantage of causing soaring.

JP-A-6-173877 (FIGS. 8 to 17)

  The present invention does not use a conventional spherical bearing that causes a significant increase in cost, uses a plain bearing that is low in material cost and processing cost, and gives elasticity to the structure of the sub-bearing. It is an object of the present invention to provide a highly reliable sub-bearing structure by reducing the bearing inner diameter and crankshaft contact caused by deflection and the like to reduce the sliding surface pressure.

  A housing comprising a cylindrical portion into which a simple cylindrical bearing bush serving as a slide bearing is press-fitted, and a flange portion that is fixed to the auxiliary bearing joint surface of the auxiliary bearing support frame attached to the sealed container by welding or the like; An elastic structure is provided at the connecting portion of the cylindrical portion and the flange portion, and the inner diameter of the bearing bush and the inclination of the axis of the auxiliary bearing portion of the rotating shaft are absorbed by the elastic deformation of the connecting portion having elasticity, and the auxiliary bearing The problem can be solved by following the sliding surface to reduce the sliding surface pressure and improving the wear resistance.

  Spherical bearings with self-aligning performance that are used in conventionally known scroll compressors are made by grinding the outer spherical surface of the spherical bearing and the inner spherical surface of the housing with special processing equipment, and also using carbon steel with poor lubricity. In order to improve wear resistance, spherical hardening and nitriding treatment are performed, and molybdenum disulfide coating and manganese phosphate treatment are carried out to improve familiarity. As a result, the manufacturing cost has been soaring.

  Therefore, the present invention uses a slide bearing using an inexpensive bearing bush as a bearing for the purpose of significantly reducing the cost, and an elastic shape portion is provided in a housing for press-fitting the bearing, thereby tilting the auxiliary bearing portion. The bearing bush is provided with a surface layer of a porous sintered layer made of bronze powder (which may be impregnated with a fluororesin) having excellent lubricity and wear resistance. Using a sheet-wound bushing, the sliding surface pressure is reduced and the conformability is improved by local deformation of the surface layer having excellent plastic formability, and smooth sliding performance is obtained.

  In addition, by using a carbon material having excellent solid lubricity for the bearing bush to prevent seizure, it is possible to provide an inexpensive and highly reliable bearing structure in combination with the elastic action of the housing of the present invention.

  The present invention has been described by taking a scroll compressor as an example, but if it is a rotary compressor or pump having a secondary bearing as in the present invention, it can be applied to apply the same as in the present invention. Performance and cost reduction effect can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  Here, 1 is an airtight container, 2 is a compression mechanism part, 3 is a fixed scroll, 4 is a turning scroll, 5 is a compression chamber, 6 is a crankshaft, 7 is an Oldham ring, 8 is a frame, 9 is a main bearing, 10 is An auxiliary bearing, 11 is a housing, 12 is an auxiliary bearing support frame, 13 is an electric motor, 14 is a stator, 15 is a rotor, 16 is a bearing bush, 17 is a grinding wheel, and 18 is a wound bush.

  FIG. 1 is a longitudinal sectional view showing an example of the scroll compressor of the present invention.

  That is, the compression mechanism portion 2 is accommodated in the upper portion and the electric motor 12 is accommodated in the lower portion of the sealed container 1 as shown in FIG. 1, and the compression mechanism portion 2 is a fixed scroll 3 in which a spiral wrap 3b stands on an end plate 3a. And a plurality of compression chambers 5 are formed by meshing the respective wraps 3b and 4b of the orbiting scroll 4 with the spiral wrap 4b upright on the end plate 4a. The crankshaft 6 has its eccentric portion 6 a fitted into the boss portion of the orbiting scroll 4 to transmit the rotational force of the electric motor 13 and revolve the orbiting scroll 4. The orbiting scroll 4 is prevented from rotating by the action of the Oldham ring 7.

  The orbiting scroll 4 is accommodated in the frame 8, the fixed scroll 3 is fastened, and the crankshaft 6 is rotatably inserted into and supported by the main bearing 9 of the frame 8.

  The sub-bearing 10 is disposed on the side opposite to the motor (below the motor 12) with respect to the main bearing 9, and the sub-bearing 10 is press-fitted into the inner diameter of the hermetic container 1 and fixedly joined by welding or the like. Twelve sub-bearing joint surfaces 12a are fixedly connected. The electric motor 13 includes a stator 14 and a rotor 15, and the crankshaft 6 coupled to the rotor 15 is supported by a main bearing 9 and a sub-bearing 10 provided on both sides of the electric motor 13.

  The main bearing 9 is a general sliding bearing having a straight inner diameter surface as in the conventional known technology.

  On the other hand, in the present invention, the auxiliary bearing 10 uses a bearing bush 16 that is a plain bearing having a straight inner surface as in the main bearing.

  This sub-bearing is formed by press-fitting a bearing bush 16 into the housing 11, and the configuration method will be described in detail with reference to FIGS.

  FIG. 2 is a fragmentary enlarged view showing an example of the auxiliary bearing structure of the present invention, as viewed from the direction of arrow F in FIG. That is, the bearing bush 16 is press-fitted into the cylindrical portion 11 a of the housing 11, and the cylindrical portion 11 a of the housing 11 is integrally connected by the flange portion 11 c and the thin-walled connecting portion 11 b. In a state where the inner diameters of the portion 6b and the bearing bush 16 are fitted, they are attached to the auxiliary bearing joint surface 12a of the auxiliary bearing support frame 12 by welding (not shown) or the like.

  FIG. 3 shows an inner surface grinding machine (not shown) with the inner diameter of the bearing bush 16 after press-fitting the housing 11 as a reference with respect to the end face of the flange portion 11c so as to be fitted to the auxiliary bearing portion 6b of the crankshaft 6 as shown in FIG. Thus, an example of a state in which the grinding wheel 17 is precisely machined so as to form an appropriate sliding clearance with the auxiliary bearing portion 6b of the rotating shaft 6 is shown.

  Here, the basic structure of the housing 11 is a flange portion 11c that is fixedly bonded by welding or the like between the cylindrical portion into which the bearing bush 16 is press-fitted and the sub-bearing joining frame 12, and a connecting portion that elastically connects both of them. 2 is not limited to the example shown in FIG. 2 and may be as shown in FIG. 4. The installation space of the secondary bearing and the inclination of the secondary bearing joint surface 12 a of the secondary bearing support frame 12 fixedly attached to the hermetic container 1 may be used. The shape may be freely selected depending on the degree of elasticity required from the above.

  FIG. 5 shows an example of the assembly state of the housing 11 to the scroll compressor described above.

  That is, if the right angle between the flange surface 11d of the housing 11 and the inner diameter of the bearing bush 16 cannot be secured due to the inclination of the auxiliary bearing support frame 12 with respect to the sealed container or the inclination of the crankshaft 6, the connecting portion 11b of the housing 11 is elastically deformed. Then, the inner diameter of the bearing bush 16 follows the outer diameter of the crankshaft 6.

  On the other hand, the bearing bush 16 is required to have excellent sliding lubricity, but is a metal plate provided with a porous sintered layer made of bronze powder as a surface layer, which is generally inexpensive and easily used. A winding bush 18 in which the surface layer is rolled inwardly is used frequently.

  FIG. 6 shows a method for manufacturing the wound bush 18, which is made by winding a metal plate 18b having a surface layer 18a excellent in lubricity and wear resistance with the surface layer inside. The cross section of the winding bush 18 is composed of a metal plate 18b, a bronze powder porous sintered layer 18c, and a surface layer 18d impregnated with a fluororesin in order from the outside. 18e shows bronze powder.

  In the above-described FIG. 6, the porous sintered layer 18c made of bronze powder is impregnated with a fluororesin so as to further improve the lubricity of the surface layer 18a. A wound bush 18 (not shown) having a porous sintered layer 18c made of bronze powder that is not impregnated as a surface layer 18a is widely used.

  By using a wound bushing having the porous sintered layer 18c made of bronze powder and the surface layer 18a rarely impregnated with a fluororesin, combined with the elastic deformation effect of the connecting portion of the housing 11 of the present invention. By using this, the following effects are exhibited.

  That is, in the assembled state of the auxiliary bearing 10 according to the present invention, the bearing surface effectively follows to some extent by the elastic action of the connecting portion 11b of the housing 11 as described above. In comparison, even if the right angle accuracy of the flange surface 11d of the housing 11 and the inner surface of the auxiliary bearing 10 (winding bush 18) is precisely formed by the above-described abrasive processing, the auxiliary bearing of the auxiliary bearing support frame 12 attached to the sealed container 1 is used. The deflection of the joint surface 12a and the compression mechanism portion 2 of the crankshaft 6 causes the inclination of the axis of the auxiliary bearing 10 with respect to the axis of the auxiliary bearing portion 6a of the rotary shaft 6, and one-side contact (line contact). May occur. However, even if the operation is continued in that state, the bearing surface having the bronze powder porous sintered layer 18c is subjected to the reaction force of the gas pressure due to the operation of the compression mechanism portion 2 and the deflection of the crankshaft 6 as shown in FIG. The plastic deformation is caused by the force, and the portion shown by hatching of the auxiliary bearing 10, that is, the portion that is locally in line contact disappears, the area of the sliding surface is enlarged, the sliding surface pressure is reduced, and the sliding reliability Can be obtained.

  Similarly, the bearing surface having the porous sintered layer 18c made of bronze powder is deformed (not shown) in the lower line contact portion of the auxiliary bearing 10, and sliding reliability can be obtained.

  Further, by adopting a carbon bearing (not shown) having excellent solid lubricity for the bearing bush 16, the sub-bearing portion 10 in which one end contact (line contact) is produced as shown in FIG. Even when the oil film breaks, the contact portion can be prevented from being seized, and the sliding characteristics can be efficiently enhanced by combining with the housing using the elastic connecting portion of the present invention.

The longitudinal cross-sectional view which shows an example of the scroll compressor concerning this invention. F arrow figure of the compressor shown in FIG. The side view which shows an example of the abrasive grain (grinding) process of the internal diameter of the subbearing concerning this invention. The sectional side view which shows another example of the formation method of the subbearing concerning this invention. The sectional side view which shows an example of the condition of the inclination assembly with respect to the crankshaft axial center of the subbearing concerning this invention. The perspective view explaining an example of the winding bush used for the bearing of the compressor shown in FIG. The sectional side view which shows an example of the sliding face shape after the driving | operation of the winding bush of the bronze powder porous sintered layer used for the subbearing of this invention. The longitudinal cross-sectional view which shows an example of the scroll compressor concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sealed container, 2 ... Compression mechanism part, 3 ... Fixed scroll, 3a ... End plate, 3b ... Wrap, 4 ... Orbiting scroll, 4a ... End plate, 4b ... Wrap, 5 ... Compression chamber, 6 ... Crankshaft, 6a ... Eccentric part, 6b ... Sub bearing part, 7 ... Oldham ring, 8 ... Frame, 9 ... Main bearing, 10 ... Sub bearing, 11 ... Housing, 11a ... Cylindrical part, 11b ... Linking part, 11c ... Flange part, 11d ... Flange Surface 12, auxiliary bearing support frame, 12 a, auxiliary bearing joint surface, 13 electric motor, 14 stator, 15 rotor, 16 bearing bush, 17 grinding wheel, 18 winding bush, 18 a surface layer, 18 b Metal plate, 18c: Bronze powder porous sintered layer, 18d: Surface layer impregnated with fluororesin, 18e: Bronze powder.

Claims (4)

An airtight container accommodates an electric motor and a compression mechanism connected to the electric motor. Each of the end plates has a spiral wrap, and a compression chamber is formed by engaging the wrap. A fixed scroll and an orbiting scroll; a crankshaft for transmitting the rotational force of the electric motor to revolve the orbiting scroll; a frame having a main bearing for supporting and rotating the crankshaft; and means for preventing rotation of the orbiting scroll, In the scroll compressor provided with a secondary bearing supporting the crankshaft on the side opposite to the frame of the electric motor,
The auxiliary bearing is constituted by a bearing bush that becomes a slide bearing and a housing that press-fits the bearing bush, and the housing is formed by a cylindrical portion that press-fits the bearing bush, and a flange portion that is elastically linked integrally with the cylindrical portion, The bearing bush is press-fitted into the cylindrical portion of the housing and subjected to precision machining, and the flange portion of the housing is attached to the auxiliary bearing joint surface of the auxiliary bearing support frame fixedly attached to the inner diameter of the sealed container by welding or the like. Scroll compressor.   For the bearing bush of the secondary bearing, using a winding bush made by winding a metal plate provided with a porous sintered layer made of bronze powder having lubricity and wear resistance with the sintered layer inside, The scroll compressor according to claim 1, wherein this is press-fitted into a housing, and a sintered layer having an inner diameter of a wound bush is subjected to abrasive processing.   A metal plate having a surface layer impregnated with a fluororesin in a bronze powder porous sintered layer having lubricity and wear resistance is wound on the bearing bush of the secondary bearing with the surface layer inside. 2. The scroll compressor according to claim 1, wherein the winding bush is press-fitted into a housing, and the surface layer of the inner diameter of the winding bush is subjected to abrasive processing. 2. The scroll compressor according to claim 1, wherein a carbon sintered bush having solid lubricity is used as a bearing bush of the sub-bearing, and this is press-fitted into a housing and the inner diameter thereof is subjected to abrasive processing.

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