CN100545451C

CN100545451C - Hermetic compressor and refrigeration plant and refrigerator

Info

Publication number: CN100545451C
Application number: CNB2007100082054A
Authority: CN
Inventors: 佐藤真一; 石山明彦; 绀野元; 长尾智大; 别役健二
Original assignee: Hitachi Appliances Inc
Current assignee: Meizhi Weiling application parts (Thailand) Co.,Ltd.
Priority date: 2006-03-20
Filing date: 2007-01-25
Publication date: 2009-09-30
Anticipated expiration: 2027-01-25
Also published as: KR100883532B1; SG155937A1; SG136028A1; KR20070095185A; JP2007248020A; CN101042125A; JP4996867B2; KR20080046154A; KR100856629B1

Abstract

The invention provides a kind of hermetic compressor and refrigeration plant and refrigerator, realize to use energy-conservation, miniaturization, the high efficiency of refrigeration plant etc. of the refrigeration agent of hydrocarbon system, improve reliability simultaneously.The refrigeration plant of this hermetic compressor holds compression unit and electrodynamic element in use in closed container, and utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, use isobutane (R600a) with the compression unit refrigerant compressed, and refrigerating machine oil uses the fatty acid ester oil that has ester bond in the molecule, thereby improve the lubricity of slide part, realize that simultaneously high efficiency and reliability improve.

Description

Hermetic compressor and refrigeration plant and refrigerator

Technical field

The present invention relates to use hermetic compressor and the refrigeration plant and the refrigerator of hydrocarbon as refrigeration agent.

Background technique

In the past, on the refrigeration agent of refrigerator or air regulator, used CFC (chlorofluorocarbons), but, be limited in the world to use, and be converted to as this refrigeration agent that does not contain chlorine of HFC (hydrofluorocarbon) refrigeration agent owing to consider environmental problem.Particularly, have the thermodynamic properties close with CFC12 (dichlorodifluoromethane) R134a (1,1,1,2-tetrafluoroethane) be used for refrigerator.At this moment, replace the mineral oil with R134a refrigeration agent intermiscibility difference, ester oil is used on the refrigerating machine oil and is practical.In patent documentation 1 (spy opens flat 4-183788 communique), disclose refrigeration agent and used the R134a of HFC system, and used the example of ester oil as refrigerating machine oil.

But though the HFC refrigeration agent can not damage the ozone layer, the greenhouse effect coefficient is big, from preventing the viewpoint of global warming, uses the natural refrigeration agents such as HC (hydrocarbon) refrigeration agent of hydrocarbon system this year, on refrigeration plants such as refrigerator just in practicability.In fact, use the refrigerator commercialization of the little HC refrigeration agent of global warming coefficient for the replacement refrigeration agent in Europe.

In Japan preventing of holding in 1997 arranged also it is the background of greenhouse effect material that appointment HFC refrigeration agent is gone up in global warming capital of a country meeting (COP3), makes, sells the refrigerator that isobutane (R600a) is used for refrigeration agent before and after 2002.

For HC refrigeration agents such as propane (R290) or isobutane, the mineral oil intermiscibility height of naphthene series or paraffin series.And, good acquired or Economy is arranged, in the refrigeration plant that uses the HC refrigeration agent, use mineral oil (with reference to patent documentation 2: the spy opens the 2004-60952 communique) as refrigerating machine oil.In addition, the content that can use ester oil as the refrigerating machine oil of the refrigeration plant that uses the HC refrigeration agent is also disclosed in patent documentation 3 (spy opens the 2002-38135 communique).

In addition, refrigeration plant is connected in series and constitutes with the bottom: the compressor that is used for High Temperature High Pressure ground compressed refrigerant; The coagulator of compressed refrigeration agent as liquid refrigerant condenses; The decompressions (expansion) such as capillary tube that refrigeration agent through coagulator reduces pressure are installed; And the vaporizer that evaporates the refrigeration agent that is depressurized.In refrigerator or air regulator, use hermetic compressor, shown in patent documentation 4～6 (be followed successively by spy open 2003-184751 communique, spy are opened the 2003-214343 communique, the spy opens the 2004-27969 communique), adopt the structure of in closed container, holding compression unit and electrodynamic element.

As the known reciprocal compressor with pistons reciprocating as patent documentation 4～6 of hermetic compressor, reciprocal compressor connects crankshaft and piston with connecting rod (con rod), and reciprocating structure is changed in the motion that becomes the axle that will rotatablely move.

As the Placement of piston and connecting rod, known have a so-called ball pivot mode of utilizing spherical bearing to connect, also adopts this mode in the hermetic compressor of patent documentation 4～5.In patent documentation 4, eliminate the part of the outer spherical surface of the part of inner ball surface of piston and connecting rod simultaneously, be inserted into rotary-piston behind the interior bulb of piston in outer ball portion and connect connecting rod and piston connecting rod.

In patent documentation 5, the inner ball surface that is arranged on the piston is made the structure that utilizes the plastic working moulding, coat the spheroid portion that supports an end that constitutes connecting rod.And, between spheroid portion and inner ball surface, get involved thermoplastic resin material.

On the other hand, patent documentation 6 uses wrist pin in being connected of piston and connecting rod.The wrist pin mode is the position of alignment piston and connecting rod, as one man inserts wrist pin with the bearing of trend of bent axle and is connected.And, constitute structure to the slide part supplying lubricating oil of piston or wrist pin.

It is more and more stricter that the requirement of energy-conservationization of refrigeration plant, miniaturization and high efficiency in recent years becomes, more and more harsher to the interior condition of hermetic compressor.Refrigerating machine oil plays the effect of the slide part in lubricated or the coolant compressors such as sealing, cooling, but considers from the reliability aspect of guaranteeing compressor, requires the particularly refrigerating machine oil of high abrasion resistance of lubricity.

In patent documentation 2, naphthene series or paraffin series mineral oil are used for refrigerating machine oil, but because too high, and the decline of the viscosity of refrigeration agent/oily mixed solution takes place easily with the dissolubility of isobutane (R600a).And be easy to generate foam, do not have the oil condition of supply so become easily, thereby can worry insufficient lubrication.

In addition, the mineral oil of naphthene series or paraffin series constitutes molecular configuration by hydrocarbon, is roughly non-polar oil, thus can not be adsorbed on the slide member of iron system, thus there is the problem that is difficult to form oil film.And, because the HC refrigeration agent from do not comprise chlorine or fluorine in refrigerant molecules, therefore can not be expected the lubricity of refrigeration agent self.

In patent documentation 3, disclose the example that refrigerating machine oil uses ester oil, but be not the refrigerating machine oil of harshnessization of the above-mentioned interior condition of corresponding hermetic compressor.

Use motor as the electrodynamic element that is used for Driven Compressor.In recent years, utilize the variable control of revolution of the motor of frequency conversionization, realize control according to load.At this moment, require running, also require high efficiency at each rotary area from the high speed rotating zone to the low speed rotation regional stability.

In addition, in hermetic compressor, the wearing and tearing of the slide part in the closed container have brought influence for the reliability of compressor.As the slide part in the closed container can exemplify between cylinder and the piston, connecting rod-piston joint or bent axle-places such as connecting rod joint.Wherein, the sliding problem of the easiest generation connecting rod-piston joint.Because the load of the connecting rod-piston joint of reciprocal compressor in the week rotation of bent axle often changes, wearing and tearing or the big problem of heating change take place in the slide part that therefore is easy to generate at connecting rod or piston, thereby need guarantee material thermal resistance (endurance) or select best refrigerating machine oil.

In addition, the harshnessization of the condition of compressor inside causes the problem of contact stress of slide part (for example connecting rod-piston joint) or heating and the temperature that produces rises.The problem of ablation (baked is paid) ultimate load that for example can exemplify problem that contact stress (pressure of contact surface) that shape or operating condition by compressor cause increases particularly, cause by the operating condition of the characteristic of refrigeration agent and refrigerating machine oil or compressor or refrigerating machine oil problem foamy etc.

As for the lubricity that improves slide part to the characteristic that refrigerating machine oil requires, can exemplify viscosity with the state that mixes of refrigeration agent.Particularly, as if the too high resistance that then becomes slip of viscosity, the tendency of the decrease in efficiency that causes refrigeration plant is arranged.On the other hand, low if viscosity is crossed then as the characteristic variation of lubricant oil, there are the sealing decline of slide part or heating, wear problems.

In patent documentation 4, connecting rod utilizes the ball pivot mode to be connected with piston.And, eliminated the part of the outer spherical surface of the part of inner ball surface of piston and connecting rod simultaneously, become that assembling is good, the structure of the miniaturization of easy implement device.In addition, guaranteed connecting rod-piston joint is supplied with the space of refrigerating machine oil.But owing to eliminated the part of the outer spherical surface of the part of inner ball surface of piston and connecting rod simultaneously, so area of contact diminishes, and that the surface pressure of slide part becomes easily is big.

In patent documentation 5, the ball support of ball pivot structure is applied two sides or the side that nitriding treatment and manganese phosphate are handled, and sphere use high-carbon chromium steel material has again, between ball and tumbler bearing, possess the shock absorber that constitutes by thermoplastic resin materials such as PTFE, PFA in addition, thereby improve wear resistance.But, carrying out the processing of shape in order to make its plastic deformation, this structure not only needs to guarantee processability, and also raises the cost easily textural.In addition, do not consider harshnessization, the increase of the wearing and tearing that cause by the high capacityization of slide part or as the characteristic of refrigerating machine oil such as the ultimate load that spumes or ablate along with the interior condition of hermetic compressor.

In patent documentation 6, adopted the mode of utilizing wrist pin to connect connecting rod and piston.And, to make the structure of guaranteeing to be used for to supply with the feed path of refrigerating machine oil, but consider because further harshnessization of the interior condition of compressor etc. not especially to slide part, surface pressure uprises or the problem of refrigerator oil viscosity decline.

Summary of the invention

The present invention makes in view of the above problems, its purpose is energy-conservationization, miniaturization and the high efficiency that realize hermetic compressor, refrigeration plant and use the refrigerator of these hermetic compressors or refrigeration plant, helps to improve the reliability of these devices simultaneously.

In order to achieve the above object, the invention provides a kind of hermetic compressor, in closed container, hold compression unit and electrodynamic element, utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, structure with the joint slip that makes above-mentioned connecting rod and above-mentioned piston, in first scheme of the present invention, use isobutane (R600a) with above-mentioned compression unit refrigerant compressed, refrigerating machine oil uses the fatty acid ester oil that has ester bond in the molecule.

In addition, in order to achieve the above object, in alternative plan, use isobutane (R600a) with above-mentioned compression unit refrigerant compressed, refrigerating machine oil uses fatty acid ester oil, and it is also big that the value that the ablation ultimate load of the Falex test of this fatty acid ester oil is scaled stress likens the hertz stress that the contact stress for above-mentioned joint converts to.Have particularly, the pressure of contact surface of above-mentioned joint is more than the 10MPa again, possesses the structure that can supply with refrigerating machine oil to above-mentioned joint.

In addition, preferred being constructed as follows in above-mentioned each mode:

(1) use the ablation ultimate load of Falex test to be the refrigerating machine oil more than the 3000N;

(2) the refrigerator oil viscosity is 5～15cSt with the dynamic viscosity coefficient under 40 ℃;

(3) as refrigerating machine oil use foaming characteristic as below the 50mL, foam stability is the fatty acid ester oil below the 10mL;

(4) as fatty acid ester oil, use following general chemical formula (1)～(3) (in the formula, R ₁Expression hydrogen or carbon number are 1～3 alkyl, R ₂Expression carbon number is 5～12 alkyl) material;

[Chemical formula 1]

[Chemical formula 2]

[chemical formula 3]

(5) in the above-mentioned fatty acid ester oil shown in general chemical formula (1)～(3), comprise the fatty acid ester oil that constitutes by unrighted acid, at this moment, added antioxidant;

(6) joint of above-mentioned piston and above-mentioned connecting rod utilizes the ball pivot mode to be connected the inner ball surface of inside of above-mentioned piston and the spheroid portion of above-mentioned connecting rod, on above-mentioned connecting rod, be provided with from the eccentric part of above-mentioned bent axle and be communicated to above-mentioned joint and supply with the through hole of refrigerating machine oil, supply with refrigerating machine oil to the surface of contact of the spheroid portion of the inner ball surface of above-mentioned piston and above-mentioned connecting rod to above-mentioned joint; And

(7) on above-mentioned piston and above-mentioned connecting rod, use the agglomerated material apply the iron system that steam treatment or gas carbonitriding handle.

In addition, in above-mentioned any structure, it is characterized in that, will be set at 0.1 μ m～2.2 μ m at 10 mean roughness of the slip surface of the above-mentioned connecting rod of the joint of above-mentioned piston and above-mentioned connecting rod.Have again, it is characterized in that, will be set at 3 μ m～10 μ m at both gap size of the joint of piston and connecting rod.

In addition, third party's case of the present invention provides a kind of refrigeration plant, in closed container, hold compression unit and electrodynamic element, utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, in above-mentioned compression unit, have and directly connect coagulator, the mechanism of decompressor and vaporizer on the hermetic compressor of slide part, use isobutane (R600a) with above-mentioned compression unit refrigerant compressed, refrigerating machine oil uses the fatty acid ester oil that has ester bond in the molecule.

In addition, cubic case of the present invention possesses: hold compression unit and electrodynamic element in closed container, and utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, and have the hermetic compressor of slide part in above-mentioned compression unit; And be provided in the adiabatic space inside that separates above-mentioned hermetic compressor and adiabatic wall, and constitute the vaporizer of refrigeration cycle with above-mentioned hermetic compressor, as using isobutane (R600a), as the fatty acid ester oil that has ester bond in the refrigerating machine oil use molecule with the compression of above-mentioned compression unit and with the refrigeration agent of above-mentioned evaporator evaporation.

The present invention has following effect.

According to the present invention, can realize energy-conservationization, miniaturization, the high efficiency of hermetic compressor, refrigeration plant or refrigerator, improve reliability simultaneously.

Description of drawings

Fig. 1 is the figure of the refrigeration cycle of expression present embodiment.

Fig. 2 is the schematic representation of the refrigerator of expression present embodiment.

Fig. 3 is the longitudinal section of the hermetic compressor of present embodiment.

Fig. 4 is the in-built figure of expression piston.

Fig. 5 is the figure of the shape of expression connecting rod.

Fig. 6 is the stereogram of anticreep parts.

Fig. 7 is the figure of the assembling condition of expression piston and connecting rod.

Fig. 8 is the chart of expression wearing and tearing development.

Fig. 9 is expression wearing and tearing sliding test result's a chart.

Figure 10 is the figure of the ablation ultimate load of expression refrigerating machine oil.

Figure 11 is the figure of the relation of presentation surface roughness and ablation ultimate load.

Figure 12 is the concept map of the load of the point of contact in Falex test.

Among the figure:

The 1-cylinder; The 2-connecting rod; 2a-spheroid portion; 2a '-planar surface portion; The 4-piston; The inner ball surface of 4a-piston; The 4c-groove; The 7-bent axle; 10-anticreep parts; 10a-first spring section; 10b-second spring section; The 10c-supporting portion; 10d-rotates limitation part; 10d '-male portion; The 10e-extension part; The 100-hermetic compressor; The 101-testing machine; The 102-test film; The 110-coagulator; The 111-refrigerant piping; The 115-exsiccator; The 120-capillary tube; The 130-vaporizer.

Embodiment

Below, use the description of drawings one embodiment of the present invention.

Fig. 1 is the figure of the refrigeration plant of expression one embodiment of the present invention, and Fig. 2 is the schematic representation of the refrigerator of expression one embodiment of the present invention.

As shown in Figure 1, refrigeration plant is connected in series with refrigerant piping 111 and forms with the bottom: with the hermetic compressor 100 of refrigeration agent High Temperature High Pressure ground compression; By the condense coagulator 110 of refrigeration agent of heat radiation; Capillary tube 120 as the mechanism of decompressor; And, generate the vaporizer 130 of cold air by the refrigeration agent evaporation is absorbed heat.Solid arrow among the figure is represented the flow direction of refrigeration agent, and dotted arrow represents that heat moves.

Refrigeration plant is packed in the body of thermal insulating box, forms refrigerator.As shown in Figure 2, be connected in series hermetic compressor 100, coagulator 110, capillary tube 120 and vaporizer 130.Vaporizer 130 is provided in the case, utilizes in the change of state cooler bin of the refrigeration agent that flows in refrigerant piping 111.In addition, on the refrigerant piping 111 that the periphery along body of thermal insulating box sets, also dispel the heat, as the parts of the around openings generation dewfall that is suppressed at refrigerator.What represent with mark 115 in addition, is exsiccator.

Fig. 3 is the longitudinal section of the hermetic compressor 100 of one embodiment of the present invention.The hermetic compressor of present embodiment is to make piston 4 to-and-fro motion and constitute the reciprocal compressor of compression unit in cylinder 1, and this cylinder 1 is one-body molded with the 1a of bearing portion and the frame 1b that are arranged in the closed container.Possess stator 5 and the rotor 6 that constitutes motor in the bottom of frame 1b as electrodynamic element, be provided with crank pin 7a in position from the rotating center off-centre of bent axle 7.

Bent axle 7 connects the 1a of bearing portion of frame and extends to top from the bottom of frame 1b, is arranged to the upper side that crank pin 7a is positioned at frame 1b.The bottom of bent axle 7 directly is connected with rotor 6, and bent axle 7 utilizes the power rotation of motor.Connect with connecting rod 2 between crank pin 7a and the piston 4, become by crank pin 7a and connecting rod 2 pistons 4 reciprocating structures.

That is, the hermetic compressor of present embodiment, promptly holds cylinder 1, piston 4 etc. and compresses electrodynamic elements such as unit and motor as prerequisite with following structure in closed container, the rotating force that utilizes bent axle 7 to transmit from electrodynamic element.Joint construction about connecting rod 2 and piston 4 will be narrated in the back, and piston 4 has inner ball surface at bent axle 7 side openings in this opening.

So the refrigeration agent of supplying with in cylinder 1 is compressed by the to-and-fro motion of piston 4, in the discharge tube that compressed gas refrigerant is transported to cylinder head side is communicated with.Refrigeration agent returns in the compressor once more through coagulator, the mechanism of decompressor, vaporizer, forms to have the refrigeration cycle of these each mechanisms.

There is refrigerating machine oil (lubricant oil) in the closed container inner product, draws up with the pumping action that rotatablely moves that relies on bent axle 7, and be transported to compression unit portion.In addition, this refrigeration plant uses the refrigeration agent (HC refrigeration agent) of propane (R290) or isobutane hydrocarbon systems such as (R600a).And as the preferred isobutane of refrigeration agent (R600a) that is used for refrigerator.

Then use Fig. 4 that piston 4 is described.Fig. 4 is the figure of the piston 4 of expression present embodiment, and Fig. 4 (a) is the details drawing of the inboard structure of piston 4, is the figure that sees piston 4 from bent axle 7 sides, and Fig. 4 (b) is the A-A sectional view of Fig. 4 (a), and Fig. 4 (c) is the B-B sectional view of Fig. 4 (a).

As shown in Figure 3, under piston 4 was installed on state in the hermetic compressor, the above-below direction of Fig. 4 (a) was consistent with the above-below direction of the hermetic compressor of Fig. 3.And the left and right directions of Fig. 4 (a) becomes junction surface front side and inboard substantially horizontal in Fig. 3.Thereby to be expression see that from the upside of piston 4 or downside figure as the state of the A-A section of the section of horizontal plane, Fig. 4 (c) are expressions from the left side of piston 4 or figure as the state of the B-B section of the section of vertical is seen on the right side to Fig. 4 (b).In addition, the downside in Fig. 4 (b) among the figure becomes the inboard of piston 4, and the right side in Fig. 4 (c) among the figure becomes the inboard of piston 4.

As described later, the inner ball surface 4a of piston 4 is the parts that constitute the bearing construction of the outer spherical surface that supports the spheroid portion on the front end that is arranged at connecting rod 2, becomes the shape that coats the outer spherical surface of connecting rod 2 with the angle more than 180 ° in the A-A section.Thereby the outer spherical surface of connecting rod 2 is coated by the inner ball surface 4a of piston 4 and supports, and connects connecting rod 2 and piston 4.On the other hand, in the B-B section, become the shape that coats the outer spherical surface of connecting rod 2 with the angle below 180 °, become the slide area structure also littler in the B-B section than A-A section.

Like this, because therefore the central angle of circular arc of substantially horizontal (A-A section) that is formed on inner ball surface 4a becomes the ball pivot structure of the section that slide area is little on above-below direction than the big structure of central angle at the circular arc of vertical (B-B section).Thereby lubricant oil passes through easily, and the path self that lubricant oil passes through also shortens, and lubricant oil flows into and flows out at joint easily, can reduce because the wearing and tearing of sliding etc.And, owing to guaranteed the inflow and outflow of lubricant oil inside and outside slide part, therefore can suppress the abnormal heating of slide part.In addition, owing to have recess, therefore can further reduce slip surface in the inboard of inner ball surface 4a.

Under the state of hermetic compressor running, piston 4 has a slide part inside and outside.That is, be between the inner peripheral surface of the periphery of piston 4 and cylinder 1 slip and with the slip of the attachment portion of connecting rod 2.Inner ball surface 4a be and connecting rod 2 between slide part, if slide area diminishes, then have the part that wearing and tearing take place to diminish and pressure of contact surface becomes big tendency.

As shown in Figure 4, have recess 4a ', and the slip surface of above-below direction is local to be formed in the inboard of inner ball surface 4a.If will remove the part of recess 4a ' as slide part from the circular arc of inner ball surface 4a, then the radius at inner ball surface 4a is the occasion of r, the size of the slide part of substantially horizontal is r * θ 41 * 2, is r * θ 42 * 2 (with reference to Fig. 4 (b), (c)) on above-below direction to this.Because θ 41＞θ 42, therefore above the inner ball surface 4a of the inboard of the perimembranous that is positioned at piston 4 or below have the space, in this space, set anticreep parts 10.

Then, the connecting rod 2 that uses Fig. 5 explanation to be connected with piston 4.The connecting rod 2 of present embodiment be the 2a of spheroid portion that the inner ball surface 4a with piston 4 is connected as an end, the other end is the 2b of bearing portion that is connected with bent axle 7, and has the structure of the 2c of bar portion that connects these two ends, Fig. 5 is the stereogram that possesses the connecting rod 2 of this structure.

As shown in the figure, connecting rod 2 possesses: the interior 2a of spheroid portion of inner ball surface 4a that inserts piston 4; Insert the 2b of radial bearing portion of crank pin 7a; And the 2c of bar portion that connects spheroid 2a of portion and the 2b of radial bearing portion, the outer spherical surface of the 2a of spheroid portion becomes the structure that the part of spheroid is cut.

Like this, because a side and the opposite side made at the 2a of spheroid portion have the structure of planar surface portion 2a ', so even connect piston 4 and connecting rod 2, the path that lubricant oil passes through is also short, and because lubricant oil is mobile easily, can be so become to the structure of sliding parts supplying lubricating oil.

Connecting rod 2 and piston 4 be connected planar surface portion 2a ' on the 2a of spheroid portion that utilization is arranged at connecting rod 2.Shown in Fig. 4 (b), the inner ball surface 4a of piston 4 becomes the shape that coats the 2a of spheroid portion of connecting rod 2 with the angle more than 180 °, becomes the also little size of external diameter than the 2a of spheroid portion at the opening size L of the inner ball surface 4a of A-A section.On the other hand, the size between two planar surface portion 2a ' is set at also littler than the opening size L of inner ball surface 4a.The part of this opening size L becomes the gap of the 2a of spheroid portion that is used to insert connecting rod 2.

The planar surface portion of present embodiment is made as almost parallel, insert two average facial 2a ' in the opening of inner ball surface 4a after, makes the rotation and be connected both relatively of connecting rod 2 and piston 4.

There are not following situation in connecting rod 2 of Lian Jieing and piston 4 like this, and the slide relative that does not even have both then owing to the opening size of inner ball surface 4a also little the coming off of external diameter than the 2a of spheroid portion, in addition, can reduce slide part.

But if owing to any effects such as impact are rotated both relatively, then connecting rod 2 was disengaged with being connected of piston 4, so possess anticreep parts 10 in the present embodiment in order to prevent dockingundocking.

Use Fig. 6 and Fig. 7 that anticreep parts 10 are described.Fig. 6 is the stereogram of the anticreep parts 10 of present embodiment, and Fig. 7 is that expression is packed anticreep parts 10 into and the figure of the state of the piston 4 that connects and connecting rod 2.As a feature, anticreep parts 10 become the shape that has concurrently as the effect of the counterrotating rotation limitation part that prevents connecting rod 2 and piston 4, are fixed on piston 4 sides, are not in connecting rod 2 sides.

As shown in Figure 6, anticreep parts (and the rotation restricting unit of present embodiment.Below identical) 10 possess: the first spring section 10a; The second spring section 10b; The supporting portion 10c that connects these two elastic portions; And the counterrotating rotation limitation part 10d of limiting rod 2.In these constituted, the interior perimembranous butt of the open interior of the first spring section 10a and the second spring section 10b and piston 4 was by resilient support anticreep parts 10.

Rotation limitation part 10d is the parts that are formed for will counterrotating occasion limiting at connecting rod 2 and piston 4 this relative wall, and these walls are oppositely arranged.Under the state of installing connecting rods 2, be arranged at planar surface portion 2a ' and relative configuration of each rotation limitation part 10d on the 2a of spheroid portion of connecting rod 2.

Rotation limitation part 10d has the part of general plane, and, be configured such that two relative rotation limitation part 10d almost parallels.That is, between two relative rotation limitation part 10d, the planar surface portion of limitation part 10d and connecting rod 2 sides is respectively rotated in relative respectively configuration.Be provided with the gap between planar surface portion 2a ' and rotation limitation part 10d, both can not make contact under common operating condition.

In addition, possesses the extension part 10e that extends laterally from supporting portion 10c.The end of extension part 10e forms to the lateral bending song opposite with

spring section

10a, 10b.

Fig. 7 is the figure that the state of these anticreep parts 10 is installed in expression, and Fig. 7 (a) is a stereogram, and Fig. 7 (b) is a sectional elevation.Anticreep parts 10 are installed, and then the first spring section 10a produces the power of the interior perimembranous 4b that pushes piston 4, anticreep parts 10 is fixed on the open interior of piston 4 by frictional force.Same second spring section also with interior perimembranous 4b butt, make anticreep parts 10 be securely fixed in the open interior of piston 4.

By so fixing anticreep parts 10, even can become piston 4 in cylinder 1 inward turning then connecting rod 2 will be rotated relatively with piston 4, connecting rod 2 can not arrive from the structure of the position that piston 4 comes off yet.

In addition, under the state in the end with extension part 10e is inserted into groove 4c, because the relation of the direction that comes off of the curved shape of extension part 10e and anticreep parts 10, the front end of extension part 10e becomes support, and can suppress coming off from piston 4.On the other hand, in the occasion that anticreep parts 10 are installed, if the end of extension part 10e is pressed into the position of groove 4c, both are cooperated simply, installation property is also good.Thereby,, and prevent the dockingundocking of piston 4 and connecting rod 2 even on the direction that piston 4 comes off, in the active force, also can suppress to come off at anticreep parts 10.

Then, the structure that is used for to slide part supplying lubricating oil (refrigerating machine oil) is described.Shown in Fig. 7 (b), on connecting rod 2, be provided with through hole 2g.Through hole 2g penetrates into the end of the 2a of spheroid portion through the bar 2c of portion from the 2b of bearing portion.The lubricant oil that accumulates in the closed container is drawn up by bent axle 7 rotations, and a part is splashed from the top of crank pin 7a.The slide part of the lubricant oil that splashes between cylinder 1 and piston 4 supplied with, and another part is incorporated into slide part between piston 4 and the connecting rod 2 by through hole 2g.

As previously mentioned, be provided with recess 4a ' in the inboard of inner ball surface 4a.This recess 4a ' plays temporarily to accumulate lubricant oil, this lubricant oil is the lubricant oil of supplying with to slide part from through hole 2g, perhaps splash and arrive the planar surface portion 2a ' of the upside that is arranged at the 2a of spheroid portion from crank pin 7a, and the lubricant oil of supplying with to slide part from the planar surface portion 2a ' of this upside.

In addition, as mentioned above, be oppositely arranged anticreep parts 10, but, therefore can supply with the lubricant oil of the planar surface portion 2a ' of process upside to slide part owing between planar surface portion 2a ' and anticreep parts 10, be provided with the gap with planar surface portion 2a '.

Slide part then is described.Because the harshnessization of the interior condition of hermetic compressor has produced the slide part wear problems and has obviously changed, and causes the problem of reliability decrease easily.So, comprehensively found that in conjunction with what real machine was investigated reason is the increase of pressure of contact surface, the undersupply of lubricant oil or the heating of slide part.

The clear and definite especially because condition of above-mentioned harshnessization, the tendency that has the contact stress of slide part to uprise.Therefore, in order to seek the optimum shape of joint, different shape has been implemented the wearing and tearing sliding test of real machine, the result is as can be known if be scaled hertz stress, this value is increased to the degree above 10MPa, and then the wearing and tearing of slide part become obviously, and then causes the decline of device whole reliability easily.Below be described in detail these opinions.

In reciprocal compressor, can exemplify slide part between connecting rod-piston joint, the piston-cylinder, bent axle-connecting rod slide part or as the bent axle of main shaft and the slide part between the bearing as main slide part as present embodiment.Hermetic compressor is as shown in Figure 3 implemented the wearing and tearing sliding test, and in these each slide parts, the wearing and tearing of connecting rod-piston joint are the most obvious as can be known for the result.

The result that the big reason of wearing and tearing quantitative change of connecting rod-piston joint is studied shows: connecting rod-piston joint and other slide parts compare, slip form difference.And as can be known, the motion of the slide part the when difference of this slip form is turned round by hermetic compressor and causing.

Here, consideration is at 1 circuit sliding distance of each slide part.(A) connecting rod-piston joint is the slide part according to the caused by relative motion of connecting rod and piston.From piston side, at ball pivot structure part, a connecting rod crankmotion predetermined angular.(B) piston-cylinder slide part is because the slide part of the caused by relative motion of piston and cylinder, and carries out the to-and-fro motion according to the distance of the offset of crank pin.(C) bent axle-connecting rod slide part is the slide part according to the caused by relative motion of bent axle (crankpin) and connecting rod, becomes the motion that the radial bearing portion one-period at connecting rod rotates a circle.(D) slide part of main shaft part is according to the slide part that rotatablely moves of the bent axle of electrodynamic element, becomes the motion that one-period rotates a circle.

If the forms of motion to the slide part of these (A)～(D) is classified, then (A) connecting rod-piston joint is the low speed to-and-fro motion, relative therewith, (B) piston-cylinder slide part is the high speed to-and-fro motion, (C) bent axle-connecting rod slide part and (D) slide part of main shaft part be high speed rotary motion.And, becoming the reciprocating connecting rod of low speed-piston joint, the load when also being applied in the refrigeration agent compression sometimes easily becomes critical lubricated easily.Relative therewith, other slide parts are because relation such as the direction of forms of motion or load and keep fluid lubrication easily.These passes tie up in the table 1 gathers.

In addition, said here high speed/low speed is relative velocity, in the present embodiment, has exemplified connecting rod-piston slide part as the slide part of Sliding velocity minimum.In addition, it is the straight line type to-and-fro motion of the slip between the barrel surface as piston-cylinder slide part that to-and-fro motion has more than, but also comprise the rotary-type to-and-fro motion of the slip between the sphere as connecting rod-piston slide part, expression outlet and the common motion in return road.

Table 1

If the slip form becomes critical lubricated, then can worry the contact between the metal covering, at this moment, wearing and tearing or heating become obvious.Thereby it is critical lubricated and can not produce the countermeasure of the situation of obvious damage to need the slip form of connecting rod-piston joint to become.Therefore, in the hermetic compressor of present embodiment, the reciprocating slide part of low speed is made further research.

In the hermetic compressor of present embodiment, the 2a of spheroid portion of the inner ball surface 4a of piston 4 and connecting rod 2 is equivalent to connecting rod-piston joint.As mentioned above, be provided with recess 4a ' in the inboard of inner ball surface 4a, the 2a of spheroid portion of connecting rod 2 part is cut and become planar surface portion 2a ', so in fact the part of Hua Donging diminishes.Particularly, be θ 42 angle parts shown in θ 41 angle parts shown in Fig. 4 (b) and Fig. 4 (c) at the slide part of inner ball surface 4a, be the part of removing planar surface portion 2a ' at the slide part of the 2a of spheroid portion.

Suppose to uprise, critical lubricating then taken place easily, carried out the evaluation of hertz stress as if contact stress at this connecting rod-piston joint.

(Young's modulus E, Poisson's ratio v) come to determine by the curvature of contacting part, the load of contacting part (N), material behavior to have the contact stress (hertz stress) of connecting rod-piston joint of above-mentioned structure.That is, if as the curvature R of the inner ball surface 4a of the piston 4 of contacting part, equally as the curvature r of the 2a of spheroid portion of the connecting rod 2 of contacting part, the load p of contacting part, the Young's modulus E of piston material _R, the Young's modulus Er of connecting rod material, the Poisson's ratio v of piston material _R, connecting rod material Poisson's ratio v _r, surface of contact radius a then ₁Available following formula is represented.At this moment, hertz stress p _Max=3P/ (2 π a ₁2).Wherein, the curvature during concave surface is calculated as negative value.Below, claim p _MaxBe hertz stress.

[formula 1]

a_{1} = \sqrt[3]{\frac{3 P}{4} (\frac{1 - {v_{R}}^{2}}{E_{R}} + \frac{1 - {v_{r}}^{2}}{E_{r}}) / (\frac{1}{R} + \frac{1}{r})}

As mentioned above, in the present embodiment,, have again in the inboard of inner ball surface 4a to be provided with recess 4a ', therefore have the surface of contact of slide part to reduce to be equivalent to the tendency of the area of this part because the part of the 2a of spheroid portion is cut.In addition, 2a of spheroid portion and inner ball surface 4a are similar to proper sphere and estimate, but if the error on considering to process or the offset of assembly error or the rotation under the real-world operation state etc. can reckon with that then the contact stress (pressure of contact surface) of the connecting rod-piston joint on real machine further becomes big in the part.That is to say, it is contemplated that the contact stress (pressure of contact surface) on real machine is also higher than the theoretical contact stress that obtains from above-mentioned formula.

For the reason of reliability decrease, further investigate.As shown in Figure 3, piston 4 utilizes ball-and-socket hinge device to be connected with connecting rod 2.At this moment, the diameter of the inner ball surface 4a of piston 4 is set at also bigger a little than the diameter of the 2a of spheroid portion of connecting rod 2, and there is the gap between.Form oil film by refrigerating machine oil in this gap, when suppressing wearing and tearing, the steady running of hermetic compressor is carried out.

If the difference of the diameter of the diameter of inner ball surface 4a and the 2a of spheroid portion diminishes, then both contacts are near " face contact ", so hertz stress reduces.On the other hand, owing to the gap reduces, so refrigerating machine oil is difficult to flow into.In addition, if consider foozle etc., then be difficult to do the gap also littler than given size.

If it is big that the difference of the diameter of the diameter of inner ball surface 4a and the 2a of spheroid portion becomes, then both contacts are near " some contact ", so hertz stress increases.In addition,,, form local contact easily, can not fully supply with refrigerating machine oil this contact segment though exteriorly the gap becomes big by calculating.

Therefore, the gap of inner ball surface 4a and the 2a of spheroid portion is defined as both radius poor, the relation of the hertz stress when being set at 0.5 μ m～10 μ m in the gap that will define and the reliability evaluation of the wearing and tearing sliding test under this hertz stress is investigated, and obtains table 2.As the load of contacting part, consider local contact, be set at 411N as representational load.In addition, refrigerating machine oil has used and the good mineral oil of HC refrigeration agent intermiscibility such as isobutane.

Table 2

Mark in the result is expressed as follows the meaning respectively.

◎: good

Zero～△: level out of question in the practicality

*: can not practical level

As can be known from these results, if hertz stress will be set at below the 10MPa, the gap need be set at about 1 μ m or below it.That is, improve reliability for the wearing and tearing that suppress to be present in the slide part in the hermetic compressor, adopting the hertz stress that suppresses slide part is that the following structure of 10MPa is more effective.

But, if as this single piece production goods of goods, then can grind etc., but to produce occasion in a large number as prerequisite in order to reduce the gap, there are foozle or assembly error etc. as mentioned above, and are difficult to do the gap also littler than given size.In addition, in the occasion that connecting rod 2 or piston 4 as slip surface are carried out steam treatment or nitriding treatment, must control surperficial thickness such as nitride film, cost becomes high on making.Therefore, other main causes that increase pressure of contact surface are studied.

As other reasons that increases pressure of contact surface, think bigger by the sneaking into of foreign matter, problem that the shape of slide part causes.Therefore, about problem, when employing is used to guarantee the structure (recess 4a ', through hole 2g, planar surface portion 2a ' etc.) of lubricant oil feed path, attempt to realize the optimization of slide part shape in the slip of piston-connecting rod joint.Particularly, make the structure that contacts of position and the 2a of spheroid portion of connecting rod 2 of avoiding becoming the reason of wearing and tearing as recess 4a ' edge on every side etc.In addition, also can on the 2a of spheroid portion of connecting rod 2, be provided for making and lodge in the drain tank that the interior foreign matter of recess 4a ' drains to the outside of recess easily.

Then, lubricant oil is studied.About lubricant oil undersupply, studied and guaranteed that lubricant oil supplies with structure (above-mentioned recess 4a ', through hole 2g, planar surface portion 2a ' etc.) and avoid taking place content foamy (about the narration in the back that spumes) simultaneously to slide part.In addition, about the problem of heating, think that the heat resistance deficiency of slide member material or refrigerating machine oil becomes the reason of wearing and tearing progress, thereby the selection of slide member material and the characteristic of refrigerating machine oil are studied.As the characteristic of refrigerating machine oil, to Falex ablation ultimate load (test method: ASTM D3233) estimate.Below, only to the occasion of ablation ultimate load, expression is according to the load of this Falex test.

Below study the hertz stress of the connecting rod-piston joint (ball pivot joint) of the hermetic compressor that is suitable for producing in batches.The external diameter (diameter) of piston 4 cylindraceous is set at 26.2mm, and at this moment, the maximum value of pressure load that is applied to the front end of piston 4 reaches roughly 1MPa, and the load that is applied in the ball pivot portion is about 400～500N.

When consider producing the piston material of property selection ferrous material and connecting rod material in batches, according to the adaptability of intensity or processability, the steel of considering to use (A) to forge (forged material), the casting thing (casting material) of (B) casting or (C) agglomerated material of sintering.Agglomerated material is because easily processing and also can suppress cost significantly, but from the viewpoint of wearing and tearing sliding properties, (A) forged material optimum, (C) agglomerated material is the poorest.Thereby think that if use agglomerated material also can guarantee the endurance of wearing and tearing and sliding, then first can realize cost degradation, second uses other materials also can suppress wearing and tearing.

It is that 0.23 iron is that (the JIS specification: SMF4040), it is that 0.21 iron is agglomerated material (JIS specification: SMF4020) as 100GPa, Poisson's ratio v that connecting rod 2 uses Young's modulus E to agglomerated material as 110GPa, Poisson's ratio v that the piston 4 of present embodiment uses Young's modulus E.And, the interior bulb diameter of the inner ball surface 4a of piston 4 is set at 13mm, gap size is set at more than the 3 μ m.That is, hertz stress is more than the 10MPa.

As shown in table 2, if hertz stress (theoretical contact stress) is also higher than 10MPa, easy generation is then arranged because the tendency of the reliability decrease of wearing and tearing.Therefore, about producing the hermetic compressor of the hertz stress that surpasses 10MPa, use multiple refrigerating machine oil to implement the sliding wear testing of slide part.The head pressure that table 3 is illustrated in refrigeration agent is the occasion of carrying out long-term sliding wear testing under the condition of 1.7MPa, 4900rpm, measures the result of the wear extent between piston and the connecting rod.

Table 3

Refrigerating machine oil	Paraffin series mineral oil (VG8)	Paraffin series mineral oil (VG10)	Ester oil
Refrigerating machine oil	Paraffin series mineral oil (VG8)	Paraffin series mineral oil (VG10)	Ester oil	The sliding wear testing result	×	×	○

Using the occasion of mineral oil at refrigerating machine oil, is that 1.7MPa, revolution are under the condition of 4900rpm heavier wearing and tearing to take place in head pressure, thus the result of reliability appears worrying, in the occasion of using ester oil (VG8, VG10), unconfirmed to significantly wearing and tearing.

Fig. 8 is the chart that is illustrated in the wearing and tearing development that changes when implementing test under the pressure condition.The head pressure of refrigeration agent and the load of slide part have substantial connection.This is because big if head pressure becomes, and then connecting rod 2 power of pushing piston 4 becomes big.Thereby big if head pressure becomes, then the contact stress at connecting rod-piston joint becomes big.

As shown in Figure 8, in the occasion of refrigerating machine oil use mineral oil, along with the time produces wearing and tearing.Represent the time history of wear extent when head pressure is 1.7MPa, 1.6MPa, 1.39MPa in the drawings, wear and tear do not have the special tendency of finding variation also just slow generation of the occasion that reduces head pressure.

On the other hand, when using ester oil as refrigerating machine oil, tendency differs widely with the occasion of mineral oil.Though knownly produce some wearing and tearing, become gradually slowly, and be in the scope of certain wear extent.And each testing machine for the gap being made as 5～10 μ m also obtains identical tendency.Promptly obtain following result: more than the gap is 5 μ m, when hertz stress surpasses 20MPa, also can suppress wearing and tearing.

Fig. 9 is the critical lubricated wearing and tearing sliding test result of imagination when using paraffin series mineral oil (VG10) and ester oil, is illustrated in the friction factor when to the wear testing machine imposed load it being slided and the warm relation of oil of lubricant oil.The longitudinal axis represent coefficientoffriction, oil temperature (℃) and load (kgf), for the convenience on the literary style, the unit of load is made as kgf.Piston material and connecting rod material and above-mentioned material do not have special variation, use the JIS specification: the iron of SMF4040, JIS specification: SMF4020 is agglomerated material, uses the material or the compound material that applies this steam treatment and gas carbonitriding processing that utilize steam treatment to form tri-iron tetroxide and seal the interparticle intergranular gap of each sintering particle.

In the drawings, compare mineral oil and ester oil, big in the occasion friction factor and the oily warm change of mineral oil, friction factor and oily temperature stably develop during ester oil.Can think that the change of friction factor or oil temperature represents the variation of surface state of slip surface or the movement of frictional heating.

In a word, in the example of mineral oil, surface state changes greatly so that the possibility height of wearing and tearing.And, if the poor lubricity of slip surface then causes the rising of oil temperature.If surplus temperature rises, then, therefore need avoid these on the performance or also undesirable on the reliability.In the example of ester oil, though exist some inhomogeneously when load load, friction factor, oil temperature all are in roughly certain scope.This expression slip surface is by sufficient lubrication.

These results are investigated, obtain as drawing a conclusion.The first, the heating of slide part of thinking the reason of wearing and tearing as can be known is by the lubricity of refrigerating machine oil, particularly the ultimate load of ablating causes with the heat resistance deficiency of material.The second, be fit to use ester oil for refrigerating machine oil as can be known, particularly in order to keep the lubricity of the slide part of heating easily, especially the ester oil of good heat stability is more effective in ester oil.Based on these conclusions, following content can be described about preferred refrigerating machine oil.

As the ester oil of the refrigeration plant that is suitable for present embodiment, preferably synthetic by polyatomic alcohol polybasic alcohol and unary fatty acid, and the type of being obstructed of good heat stability (ヒ Application ダ one De ィプ).The ester that does not have hydrogen atom here on the β carbon that the ester of the said type of being obstructed refers at hydroxyl.Approaching at the ester that has the alcohol of hydrogen atom on the β carbon (non-being obstructed) by the oxygen atom of hydrogen atom on the heating β carbon and ester bond, form the intermediate of six membered ring structure, so under low-yield, cause thermolysis easily.The ester that is obstructed does not have hydrogen atom and can not obtain six membered ring structure on β carbon, thus can not thermolysis under low-yield, and (rice leaf favour one, open country two youths write: " new edition fatty acid chemistry second edition " at high temperature to cause the thermolysis of free radical; Hot study).Thereby, used the ester that is obstructed of structure in the present embodiment with good heat stability.

For example, as polyatomic alcohol polybasic alcohol neopentyl glycol, trihydroxymethyl propane, pentaerythritol are arranged.As unary fatty acid valeric acid, caproic acid, enanthic acid, sad, 2-Methyl Butyric Acid, 2 methyl valeric acid, 2 methyl caproic acid, 2 ethyl hexanoic acid, isooctyl acid, 3 are arranged, 5,5-tri-methyl hexanoic acids etc. use these separately or use the fatty acid mixed more than 2 kinds in these.

Particularly, as the base oil of refrigerating machine oil, preferably use select in the group of ester oil of fatty acid of the following general chemical formula of the usefulness that from molecule, has two ester bonds at least (1)～(3) expressions at least a.

[Chemical formula 1]

[Chemical formula 2]

[chemical formula 3]

In formula, R ₁And R ₂Be expressed as follows content.

R ₁: H or carbon number are 1～3 alkyl

R ₂: the carbon number is 5～12 alkyl

The ester of representational chemosynthesis unary fatty acid and polyatomic alcohol polybasic alcohol shows kinetic viscosity or the dynamic viscosity coefficient (40 ℃, cSt) as table 4.

Table 4

	Neopentyl glycol	Trihydroxymethyl propane	Pentaerythritol
	Neopentyl glycol	Trihydroxymethyl propane	Pentaerythritol		2 ethyl butyric acids	4.7	18.7	45.4
Enanthic acid	5.0	-	-		2 ethyl butyric acids	4.7	18.7	45.4
Enanthic acid	5.0	-	-	2 methylhexanoic acids, 2 ethyl valeric acids, 2 thylhexoic acids	5.3	15.6	28.4
2 thylhexoic acids	7.4	24.8	47.6		5.3	15.6	28.4
2 thylhexoic acids	7.4	24.8	47.6	3,5,5 tri-methyl hexanoic acids	12.9	51.5	112.9

These fatty acid esters are as the base oil of lubricant oil, the modulation standard kinetic viscosity grade by an amount of mixing (VG:40 ℃ time dynamic viscosity coefficient (cSt)).

For example, for normal viscosity VG5, with the ester oil of neopentyl glycol and enanthic acid separately or 2 ethyl butyric acids of light viscosity oil and ester and other high viscosity ester oil hybrid modulation of neopentyl glycol, in addition, VG8, VG10, VG15, VG22, VG32 are based on same notion, low viscous neopentyl glycol ester oil and full-bodied pentaerythritol ester oil are mixed in right amount, can accurately be modulated to desirable viscosity.

In addition, also can in ester oil, add antioxidant, oxygen trapping agent, defoamer, metal inert agents etc.Fatty acid comprises unrighted acid, is effective but add antioxidant especially in the occasion of using unrighted acid.If refrigerating machine oil uses the oil with unrighted acid, then improve lubricity, at this moment, can realize the raising of sliding properties.

From above-mentioned test result clear and definite the heat resistance of refrigerating machine oil reliability is brought very big influence, therefore the ablation ultimate load of each refrigerating machine oil has been carried out estimating and representing with table 5.

Table 5

Refrigerating machine oil	Paraffin series mineral oil (VG8)	Paraffin series mineral oil (VG10)	Ester is obstructed
Refrigerating machine oil	Paraffin series mineral oil (VG8)	Paraffin series mineral oil (VG10)	Ester is obstructed	Ablation load (N)	1400	1600	3800

Can be clear and definite according to this result, the ablation ultimate load and the mineral oil of the ester oil that is obstructed (VG8, VG10) are bigger, from the sliding wear testing result as can be known, even hertz stress surpasses the raising that the hermetic compressor of 10MPa also can be realized reliability.

Therefore, be used for the occasion of refrigerating machine oil, in order further to investigate, in viscosity grade is the scope of VG5, VG10, VG15, VG22, VG32, head pressure be made as 2.0MPa and implemented high-potting at the ester oil that will be obstructed (below, abbreviate ester oil as).In the also not ablation of this exacting terms lower slider portion, suppressed the generation of wearing and tearing.In addition, can confirm,, then surpass under the environment of 10MPa and also can keep high reliability at the hertz stress of slide part if use the ablation ultimate load to surpass the refrigerating machine oil of 3000N from the result of the test of using the different refrigerating machine oil of ablation ultimate load.To the technical meaning of this 3000N, research more in the back.

Then, the material and the ablation ultimate load of piston 4 and connecting rod 2 are studied.Figure 10 is to use the connecting rod test film to measure and is using agglomerated material (the JIS specification: the chart of the ablation ultimate load of refrigerating machine oil in the time of SMF4040) of carrying out the iron system of sealing of hole by steam treatment as piston 4.As refrigerating machine oil paraffin series mineral oil (VG10) and ester oil are represented.

In addition, (the JIS specification: SMF4020), having used at 10, to estimate roughness Rz be the material of 0.1～0.2 μ m to have used the agglomerated material that applies the iron system that steam treatment and gas carbonitriding handle as connecting rod material.One of reason that connecting rod material is applied the gas carbonitriding processing is in order to improve hardness.That is, the sliding system of piston 4 and connecting rod 2 makes connecting rod 2 relative static piston motions, and passes through this both relative movement generation and slide, but if both hardness is many near the situation that then produces undesirable condition.Therefore, the hardness of the connecting rod material of the motion side of raising sliding system.

As shown in figure 10 as can be known, the ablation ultimate load and the mineral oil of ester oil is higher under in conjunction with the situation of the shape of real machine, as the excellent heat resistance of refrigerating machine oil.In fact confirm, follow the harshnessization of the running environment of compressor,, also can give full play to greasy property to the load increase or the compressor high speed rotating of slide part.

Figure 11 is the chart that is illustrated in the relation of the surface roughness of the slip surface (2a of spheroid portion) of connecting rod 2 when using ester oil as lubricant oil and ablation ultimate load.Particularly, be to use the chart of the ablation ultimate load of test material evaluation when 10 mean roughness Rz are 0.1～0.2 μ m, 0.4～0.6 μ m, 1.2～1.5 μ m.As shown in figure 11, some are inhomogeneous even produce on the surface roughness of connecting rod, also do not see a great difference of ablation ultimate load.

Therefore, the value of 10 mean roughness Rz of slip surface is the scope of 0.4～2.2 μ m after running in, has implemented real machine test.Particularly, enclosing 180g refrigeration agent R600a, is that 2.0MPa, revolution are to turn round under the condition of 4900rpm in head pressure, has confirmed the wearing and tearing of slide part afterwards.Its result not having discovery to produce big wearing and tearing under the situation of any surface roughness on piston inner ball surface 4a and the connecting rod spheroid 2a of portion, obtains good result.Can think that this is because because ester oil has the high adsorption to metal covering, thereby even surface roughness there are some differences also can guarantee lubricity.So as can be known, estimating roughness Rz at 10 after the running in is under the situation of 0.1～2.2 μ m, can obtain wearing and tearing and suppress effect.

In addition, detailed, in the occasion of using mineral oil, the ablation ultimate load changes greatly because of surface roughness.Can prefer wearing character thus changes because of surface roughness.Promptly as can be known, by using ester oil, in being the scope of 0.1～2.2 μ m, Rz can reduce the influence to lubricity of surface roughness at least.

As can be known from these results, even the inhomogeneous wearing and tearing that also can keep ester oil that some surface roughnesses are arranged suppress effect, and be effective according to the evaluation of the refrigerating machine oil of ablation ultimate load.

Therefore, based on test result, the hertz stress and the relation of the stable on heating ablation ultimate load of expression refrigerating machine oil of slide part are investigated.Obtain as drawing a conclusion from up to the present test result etc., promptly in the occasion of using agglomerated material, if use the ablation ultimate load to surpass the refrigerating machine oil of 3000N, then also can bring into play sufficient wearing and tearing and suppress effect, go on foot from the relation of hertz stress and ablation ultimate load enterprising and investigate.

Figure 12 is the concept map of the load of the point of contact in Falex test.Compress the test film of being clamped by testing machine 101 102 with load p, then testing machine 101 contacts on 4 points with test film 102.Thereby, on these point of contact, be applied in load with the P/4 of load p equidirectional.In Figure 12, as representing point of contact, be that example describes, if explain the load p of Vertical direction with load p with upper left point of contact _f, then be

Thereby in the occasion of using the ablation ultimate load as the ester oil of 3000N, point of contact is equivalent to be applied in the state of the load of about 530N.

Can derive following opinion from this research.As mentioned above, the load that is applied to ball pivot portion under common user mode is about 400～500N.Thereby,, can utilize the following fact to describe from the conclusion of " if use surpasses the ester oil of the ablation ultimate load of 3000N, the inhibition effect of then can being worn and torn fully " that the wear test result obtains.

(about 400～500N) is big than the actual load that is applied to ball pivot portion to utilize lubricant oil can guarantee the load of fluid lubrication (=approximately 530N).

Because it is littler than ester oil that mineral oil can be kept the ablation ultimate load of level of fluid lubrication, thereby produce wearing and tearing.

In other words, by use the value that the ablation ultimate load is scaled stress is likened to (for example becoming the reciprocating slide part of critical lubricated low speed easily, the slide part of connecting rod 2 and piston 4) contact stress and the also big refrigerating machine oil of hertz stress that converts can suppress to produce undue wear.

These are the evaluations when using the agglomerated material of iron system.Thereby in the occasion of using forged material and casting material, even identical shaped physical property is also different, the wearing and tearing sliding properties also changes.But as mentioned above, if wear and tear in view of agglomerated material also can suppress to produce, then clearly forged material or casting material also can suppress wearing and tearing certainly.In fact confirm, on the test level of service test sheet, even other materials also shows the wear resistance very high to wearing and tearing.

In addition, in order to improve the ablation ultimate load, except using ester oil, also consider to use the method for additive.For example, the phosphate ester (TCP) of the high-tension lubrication oil additive by adding phosphorus system in mineral oil etc. can improve the ablation ultimate load, can improve the heat resistance to sliding.In addition, polyglycols (PAG) is by using same additive, and the ablation ultimate load is also higher than ester oil, excellent heat resistance.

But ester oil possesses ester bond in molecular configuration, has the suction-operated to the metal surface, and is relative therewith, and in the occasion of using additive, if continue to use refrigeration plant, then additive is consumed gradually.Thereby, can not avoid because the long-term reliability decrease of bringing of using.In addition, PAG has the shortcoming of poor lubricity.We can say and guaranteeing which is all poor aspect the long-term reliability, thereby preferably use ester oil.In fact, as shown in Figure 8, surpass decline that also can't see greasy property in 1000 hours running time, realized stable running.

Then, the foaming of refrigerating machine oil is studied.As the foaming in closed container, except the foaming that You Yu Noise-of-dashing-waves boils, can exemplify because the foaming of stirring action.If refrigerating machine oil bubbles, then insufficient to the supply of the lubricant oil of slide part, therefore need avoid.Particularly the occasion of bubbling easily at lubricant oil perhaps is difficult to from the occasion of the recovering state that bubbles, and can be difficult to guarantee supply with oil to slide part.

Therefore, according to the result of foaming test (JIS K2518), carried out estimating and confirming about the influence that the lubricity of hermetic compressor or refrigeration plant is brought.As refrigerating machine oil use foaming characteristic in JIS K2518 test as 50mL below (24 ℃, 93.5 ℃, 93.5 ℃～24 ℃), foam stability as 10mL below the ester oil of (24 ℃, 93.5 ℃, 93.5 ℃～24 ℃), the result does not see that the reliability to hermetic compressor and refrigeration plant has considerable influence.

By using ester oil, also suppress Noise-of-dashing-waves significantly than mineral oil and boil.Can exemplify different with the intermiscibility of refrigeration agent as this reason.That is, the intermiscibility of ester oil and HC refrigeration agent is good, dissolves like that but be not so good as mineral oil.Thereby, can be suppressed at compressor start Shi De Noise-of-dashing-waves and boil, prevent abnormal sound.In addition and since with mineral oil relatively, few to dissolving in of refrigeration agent, so can remain on practical viscosity under the state of mixing, can help the raising of reliability.In fact confirm, by the ester oil that use refrigerator oil viscosity is 5～32cSt at 40 ℃ of following dynamic viscosity coefficients, can guarantee reliability, and be preferably in the high efficiency that can also realize refrigeration plant when using 5～15cSt ester oil.

Particularly, in refrigeration plant as shown in Figure 1, connect to use the refrigeration agent of as above explanation and the hermetic compressor of refrigerating machine oil, during less than 5cSt, can confirm to take place some wearing and tearing in the viscosity of ester oil, but, can not produce special problem by using the above ester oil of 5cSt.Confirming in addition, is in so-called low-pressure membrane chamber (low pressure チャ Application バ) the formula compressor of low pressure in closed container, is set at below the 15cSt by the viscosity with ester oil, and fray is in the scope out of question as the efficient of refrigeration plant.

Under the viscosity of ester oil is the low viscosity of 5～15cSt, also can guarantee reliability and high efficiency like this, as its reason can think have following some.Because the adsorptivity of ester oil and metal surface is good, so suppress effect even the low viscosity about 5cSt is also brought into play the wearing and tearing of slide part.If be situated between the high lubricant oil of viscosity arranged on slide part, then to become the resistance of slip and the tendency that has running efficiency to descend, the occasion resistance low in viscosity is little, thereby can raise the efficiency.According to these research, be the ester oil of 5～15cSt by using the dynamic viscosity coefficient under 40 ℃, can when reducing slip resistance, suppress wearing and tearing, the result can realize simultaneously that reliability is guaranteed and high efficiency.

Equally, according to the result of these researchs,, therefore, also can access same action effect in the occasion of using with the refrigerating machine oil of mineral oil because the characteristic that self is had as ester oil possesses the high adsorption with the metal surface.

Then narrate the enclosed volume of refrigeration agent.The HC refrigeration agent of Shi Yonging is flammable in the present embodiment, thereby requires to reduce the amount of enclosing in the refrigeration plant.If refrigerating machine oil uses ester oil, then reduce the refrigeration agent enclosed volume and also effective to the Security that improves refrigeration plant.It is the reasons are as follows.

In the occasion of using HC refrigeration agents such as isobutane, ester oil is compared mineral oil, decreased solubility.According to this deliquescent difference, as mentioned above, not only having bubbles suppresses effect, and also effective to the minimizing of refrigeration agent enclosed volume.If because when enclosing the refrigeration agent of same amount, the actual refrigeration agent increase that acts on refrigeration cycle is equivalent to be not dissolved in the part in the refrigerating machine oil.That is,, then can reduce the enclosed volume that is used to bring into play as the refrigeration agent of the required ability of refrigeration plant if refrigerating machine oil is changed to ester oil from mineral oil.Thereby the enclosed volume of inhibition combustible refrigerant can provide safe refrigeration plant.

Also confirm in addition, also be in level more not a halfpenny the worse when using mineral oil about COP (coefficient of refrigeration).That is, use ester oil can not cause decrease in efficiency, realized same degree or its above efficient.In addition, in the variable so-called ability various type hermetic compressor of revolution, have because the variation of running revolution, i.e. high rotationization or hang down the interior bigger tendency of temperature variation of closed container that rotationization causes, but, in each revolution zone, can realize high-efficient operation by using the ester oil that is obstructed that in the temperature band of wide ranges, can keep stable greasy property.

In the example shown in above, illustrated and used the occasion of the reciprocal compressor that connects by ball-and-socket hinge device, but be not confined to this especially.In the occasion of the reciprocating compressor that uses so-called dog link formula or wrist pin mode, also applicable to the high occasion of contact stress of slide part (the particularly reciprocating slide part of low speed).

Claims

1. hermetic compressor, it is configured to: hold compression unit and electrodynamic element in closed container, utilize connecting rod to connect crankshaft and piston with above-mentioned electrodynamic element driving, the joint of above-mentioned connecting rod and above-mentioned piston slides, it is characterized in that,

Above-mentioned joint utilizes the ball pivot mode to connect the inner ball surface of inside of above-mentioned piston and the spheroid portion of above-mentioned connecting rod,

Use isobutane (R600a) with above-mentioned compression unit refrigerant compressed,

Refrigerating machine oil uses fatty acid ester oil, and it is also big that the value that the ablation ultimate load of the Falex test of this fatty acid ester oil is scaled stress likens the hertz stress that the contact stress for above-mentioned joint converts to.

2. hermetic compressor according to claim 1 is characterized in that,

The pressure of contact surface of above-mentioned joint is more than the 10MPa, possesses structure from refrigerating machine oil to above-mentioned joint that can supply with.

3. hermetic compressor according to claim 1 is characterized in that,

Use the ablation ultimate load of Falex test to be the refrigerating machine oil more than the 3000N.

4. hermetic compressor according to claim 2 is characterized in that,

5. according to any one described hermetic compressor in the claim 1～4, it is characterized in that,

Dynamic viscosity coefficient during with 40 ℃ represents that above-mentioned refrigerator oil viscosity is 5～15cSt.

6. according to any one described hermetic compressor in the claim 1～4, it is characterized in that,

As refrigerating machine oil use foaming characteristic as below the 50mL, foam stability is the fatty acid ester oil below the 10mL.

7. hermetic compressor according to claim 5 is characterized in that,

8. according to any one described hermetic compressor in the claim 1～4, it is characterized in that,

Above-mentioned fatty acid ester oil shown in following general formula (1)～(3), in the formula, R ₁Expression hydrogen or carbon number are 1～3 alkyl, R ₂Expression carbon number is 5～12 alkyl,

[Chemical formula 1]

[Chemical formula 2]

[chemical formula 3]

9. hermetic compressor according to claim 8 is characterized in that,

Comprise the fatty acid ester oil that constitutes by unrighted acid as above-mentioned fatty acid ester oil, and be added with antioxidant.

10. according to any one described hermetic compressor in the claim 1～4, it is characterized in that,

On above-mentioned connecting rod, be provided with from the eccentric part of above-mentioned bent axle and be communicated to above-mentioned joint and supply with the through hole of refrigerating machine oil to above-mentioned joint,

Surface of contact to the spheroid portion of the inner ball surface of above-mentioned piston and above-mentioned connecting rod is supplied with refrigerating machine oil.

11. hermetic compressor according to claim 8 is characterized in that,

12. hermetic compressor according to claim 8 is characterized in that,

Above-mentioned piston and above-mentioned connecting rod use by steam treatment and form tri-iron tetroxide and the iron of sealing of hole is agglomerated material or has implemented steam treatment and the iron of the compounding of gas carbonitriding processing is agglomerated material.

13. hermetic compressor according to claim 12 is characterized in that,

10 mean roughness Rz at the slip surface of the above-mentioned connecting rod at the joint place of above-mentioned piston and above-mentioned connecting rod are 0.1 μ m～2.2 μ m.

14. hermetic compressor according to claim 10 is characterized in that,

Both gap size at the joint place of above-mentioned piston and above-mentioned connecting rod is 3 μ m～10 μ m.

15. refrigeration plant, on hermetic compressor, directly connect coagulator, the mechanism of decompressor and vaporizer, this hermetic compressor holds compression unit and electrodynamic element in closed container, utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, utilize the ball pivot mode to connect the inner ball surface of inside of above-mentioned piston and the spheroid portion of above-mentioned connecting rod, in above-mentioned compression unit, have slide part, it is characterized in that

Use isobutane (R600a) with above-mentioned compression unit refrigerant compressed, refrigerating machine oil uses fatty acid ester oil, and it is also big that the value that the ablation ultimate load of the Falex test of this fatty acid ester oil is scaled stress likens the hertz stress that the contact stress for above-mentioned joint converts to.

16. a refrigerator is characterized in that,

Possess: hermetic compressor, it holds compression unit and electrodynamic element in closed container, utilize connecting rod to connect the crankshaft and piston that drives with above-mentioned electrodynamic element, utilize the ball pivot mode to connect the inner ball surface of inside of above-mentioned piston and the spheroid portion of above-mentioned connecting rod, in above-mentioned compression unit, have slide part; And vaporizer, it is provided in the adiabatic space inside that separates above-mentioned hermetic compressor and adiabatic wall, and constitutes refrigeration cycle with above-mentioned hermetic compressor,

As with the compression of above-mentioned compression unit and with the refrigeration agent use isobutane (R600a) of above-mentioned evaporator evaporation,

Use fatty acid ester oil as refrigerating machine oil, it is also big that the value that the ablation ultimate load of the Falex test of this fatty acid ester oil is scaled stress likens the hertz stress that the contact stress for above-mentioned joint converts to.