JP2961623B2 - Swash plate compressor - Google Patents

Description

The present invention relates to a refrigerant compressor for an automotive air conditioning system,
In particular, the present invention relates to a swash plate type compressor in which a guide mechanism for a piston support has a mechanism excellent in wear resistance and seizure resistance.

[Conventional technology]

Conventionally, in this type of refrigerant compressor, a cast material of an Al-Si alloy containing about 12% by weight of silicon has been used for a front housing, and an iron-based metal material has been used for a slide shoe. . However, in the above combination, especially the wear resistance and seizure resistance of the aluminum housing side are not sufficient, and the compressor noise often increases due to the abnormal wear of the slide shoe sliding portion, or the compressor lock due to seizure often occurs. Occurred. For this reason, measures have been taken to increase the silicon content to 16 to 20% by weight in order to improve the wear resistance and seizure resistance of the aluminum alloy-based housing.

As a refrigerant for these conventional compressors, Freon 12 (R1
2), Freon 22 (R22) and the like are used, and as lubricating oils, naphthenic and paraffinic mineral oils have been used. Each of the above-mentioned refrigerants is a Freon gas containing chlorine in a molecule, and this chlorine acts as an extreme pressure agent on an active sliding surface, and in particular, has a function of improving abrasion resistance and seizure resistance of an aluminum material. In addition, the mineral oil has a high pressure viscosity index, a relatively good formation of an oil film in a high load range, abrasion resistance,
The seizure resistance was improved.

However, chlorofluorocarbon gas containing chlorine in its molecule has been determined to reduce its production by destroying the ozone layer, and will be completely abolished by the end of this century, according to the chlorofluorocarbon regulations implemented in 1989. Therefore, the development of an alternative Freon gas containing no chlorine is urgent, and at present, 1,1,1,2-tetrafluoroethane, namely Freon 134a (R134a), is a promising alternative Freon gas for R12. Therefore, improvement of wear resistance and seizure resistance by chlorine cannot be expected in the future. Correspondingly, lubricating oils have to be changed to synthetic oils such as PAG (polyalkylene glycol) because existing mineral oils are not compatible with alternative chlorofluorocarbons. This synthetic oil has a low pressure viscosity index, and has a problem in forming an oil film in a high load range. Furthermore, this synthetic oil is hygroscopic, and there is a concern that various adverse effects such as corrosion, generation of acid by hydrolysis, and hydrogen embrittlement may be caused.

From the above, it is clear that the improvement of the wear resistance and the seizure resistance of the sliding portion of the slide shoe cannot be expected after the transition to the alternative CFC, simply by increasing the silicon content of the aluminum alloy-based housing.

As a conventional example related to the present invention, there is an example of a bearing device in which an aluminum shaft having an alumite layer is combined with a synthetic resin bearing that supports the shaft, as disclosed in Japanese Utility Model Laid-Open No. 1-80822. .

[Problems to be solved by the invention]

In the above prior art, when the guide groove sliding portion of the piston support is extremely insufficiently lubricated, for example, alternative refrigerant having less lubricity than the current one due to Freon regulation, no consideration has been given after transition to an alternative refrigerating machine oil. PFC using refrigerants that do not contain chlorine in the molecule, such as chlorofluorocarbon 134a,
When a synthetic oil having a low pressure viscosity index such as is used as a lubricating oil, the sliding portion becomes insufficiently lubricated depending on the operating conditions of the compressor, and abnormal wear of the guide groove or seizure with the slide shoe. This causes a problem that the compressor is inoperable.

An object of the present invention is to improve the abrasion resistance and seizure resistance of the sliding portion of the guide mechanism for the piston support of the swash plate compressor, and to use a substitute refrigerant having an inferior lubricity and an alternative refrigeration that is inferior to the current one due to Freon regulations. It is an object of the present invention to provide a swash plate type compressor having good seizure resistance and abrasion resistance, excellent durability, and high reliability even when the machine oil is used.

[Means for solving the problem]

In order to achieve the above object, in the sliding portion of the piston support guide groove, between the groove and the slide shoe, a guide having a surface mainly composed of a synthetic resin having wear resistance and self-lubricating properties. A plate is provided, and the slide shoe slides in the groove via the guide plate.

That is, the present invention provides a housing formed of an aluminum alloy, a drive shaft rotatably supported in the housing, and a swash plate rotatably mounted around an axis perpendicular to the drive shaft. A piston support that supports a piston rod and swings in accordance with the inclination angle of the swash plate, a bearing portion protruding in a radial direction of the piston support, and formed on an inner peripheral portion of the housing in parallel with a drive shaft. A swash plate type compressor having a guide groove fitted with a bearing part, wherein a guide plate made of a solid lubricant is provided between the swash plate type compressor and the bearing part in the guide groove.

The present invention also provides a housing having a crank chamber, a suction space, and a discharge space therein, formed of an aluminum alloy, a drive shaft rotatably supported in the housing, and a drive shaft. A plurality of cylinders arranged in the circumferential direction with the drive shaft and the axis parallel to each other, a piston reciprocally fitted to each of the cylinders, and a rotatably mounted around an axis perpendicular to the drive shaft. A swash plate, rods fixed to the piston, a piston support that supports the respective rods and performs a swinging motion corresponding to the inclination angle of the swash plate, and a guide fixed in a radial direction of the piston support A pin, a slide ball reciprocally and rotatably fitted to the guide pin, and a slide shoe rotatably fitted to the inside of the slide ball,
A guide groove formed in the inner peripheral portion of the housing in parallel to the drive shaft direction and having a cylindrical groove shape, and the slide shoe is mounted so as to be rotatable and slidable in the guide groove, and the swash plate with respect to the drive shaft In the swash plate type compressor, in which the slide shoe is fitted into the guide groove when the piston is reciprocated at a stroke corresponding to the inclination angle, the movement of the piston support in the drive shaft rotation direction is suppressed. In the groove and between the sliding portion of the slide shoe,
At least a sliding surface is provided with a guide plate made of a solid lubricant.

In the compressor, the solid lubricant is made of a synthetic resin, and the synthetic resin includes an ethylene tetrafluoride resin, a polyacetal resin, a ketone resin or an imide resin. Further, the slide shoe is formed of an iron-based material, and at least the sliding surface with the guide plate has a surface roughness of Rmax of 1 mm.
It is preferable that the thickness is less than μm.

[Action]

With the above-described guide mechanism for piston support, the slide shoe has abnormal wear due to the self-lubricating property of a solid lubricant such as a surface mainly composed of synthetic resin even when the sliding portion is insufficiently lubricated. It is possible to slide smoothly in the guide groove without causing any seizure. Further, since the driving torque of the compressor decreases due to the decrease in the coefficient of friction of the sliding portion, the overall adiabatic efficiency of the compressor improves,
That is, the burden on the automobile engine can be reduced. In addition, when compared with surface treatment such as hard anodizing, it is difficult to treat only the guide groove located on the inner circumference of the housing, and if implemented, treatment of unnecessary parts of the housing is inevitable. On the other hand, in the present invention, since it is only necessary to fit a guide plate having a solid lubricant such as a surface mainly composed of synthetic resin on the surface into the guide groove, this is a more efficient method, and is cost-effective. It is also advantageous in terms of productivity.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the entire structure of a variable stroke swash plate type compressor according to the present invention. This figure shows the case where the swash plate 12 is tilted to the maximum, that is, the piston stroke is the maximum.
At one end of the cylindrical cylinder block 2, a front housing 1 that rotatably supports a main shaft 13 via a radial bearing 18 is disposed and fixed at a central portion to form a swash plate chamber 10. The housing 1 is made of die-casting such as Al-Si alloy (ADC12) or B390. The cylinder block 2 is formed with a plurality of cylinder bores 33 which are arranged in a circumferential direction parallel to the axis of the main shaft 13 which is a drive shaft. The main shaft 13 is substantially on the center line of the cylinder block 2 and is rotatably supported by radial bearings 18 and 19 provided at the center of the cylinder block 2 and the front housing 1. 14 is fixed. The drive plate 14 is provided with a cam groove 142, in which a fulcrum pin 16 fitted with a clearance in the swash plate lug 121 is movably mounted. Further, the lug 141 of the drive plate 14 provided with the cam groove 142 and the swash plate lug 121 have a structure in which the side surfaces are in contact with each other. Thus, when the drive plate 14 is rotated by the rotation of the main shaft 13, a rotational force is applied to the swash plate lugs 121 from the lugs 141 of the drive plate 14, and the swash plate 12 is rotated.

A sleeve 15 is incorporated in the main shaft 13 so as to be movable in the axial direction of the main shaft 13. The sleeve 15 and the swash plate 12 are separated from each other by a pivot pin 17.
It is fastened so that it can rotate around 17. Therefore, the rotation of the main shaft 13 causes the drive plate 14, the swash plate
12, the sleeve 15 rotates together.

A piston support 21 is fastened to the swash plate 12 via a radial bearing 23, and a spacer 22 fixed to the swash plate 12 is provided.
The bearing 23 is fixed to the hub portion 122 of the swash plate by the 1 and the retaining ring 22 so that the bearing 23 does not move in the rotation axis direction of the swash plate 12. On the other hand, the piston support 21 is restricted from moving in the right direction in FIG. 1 with respect to the radial bearing 23 by the projection 211, and furthermore, by the thrust bearing 25 installed between the piston support 21 and the swash plate 12, the left side in FIG. Movement in the direction is also regulated.

Further, a guide pin 26 is fixed to the lower position of the piston support 21 in a radial direction by press-fitting, plastic coupling, or the like,
A slide ball 27 and a pair of semi-cylindrical slide shoes 29 having a spherical portion facing the slide ball 27 are mounted on the guide pin 26 so as to rotate and move in the length direction of the pin. The slide shoe 29 reciprocates in an axial groove 28 provided in the inner peripheral portion of the front housing 1, and serves as a rotation preventing mechanism for preventing the piston support 21 from rotating around the main shaft 13. Regulate exercise.

The piston support 21 has one end of a plurality of connecting rods 32 having balls 321 and 322 at both ends.
A piston 31 is rotatably mounted around the center of the ball 321 and the other end is rotatably mounted around the center of the ball 322. The plurality of pistons 31 are cylinder bores 33
Built in. The piston 31 has piston cylinders 34 and 35 mounted thereon. The cylinder block 2 includes a suction valve plate 5, a cylinder head 4, a discharge valve plate 6,
The packing 7 and the rear cover 3 are arranged, and are fixed to the rear cover 3 integrally with the front housing 1 by bolts (not shown). Front housing 1 and cylinder block 2
The O-ring 38 and the air-tightness of the rear cover 3, the cylinder block 2 and the packing 7 are maintained by the O-ring 39.
The cylinder head 4 is provided with a suction port 401 and a discharge port 402 corresponding to each of the cylinder bores 33. The suction chamber 8 and the discharge chamber 9 provided in the rear cover 3 are connected to the cylinder bores 33, respectively.
Is communicated to. The rear cover 3 is provided with a suction port 301 and a discharge port (not shown).
A control valve 41 is arranged between the suction chamber 8 and the suction chamber 8.

With the configuration described above, when the main shaft 13 of the compressor is driven from the engine (not shown) via the magnet clutch 50, the drive plate 14 and the swash plate 12 rotate,
The piston support 21 swings with respect to the rotation axis of the main shaft 13. Therefore, the piston 31 reciprocates in the cylinder bore 33 to suck and compress the gas. Note that the maximum stroke position is regulated by bringing the sleeve 15 into contact with the drive plate 14, and the minimum stroke position is regulated by installing a retaining ring 131 in a groove provided in the main shaft 13 and applying the sleeve to the retaining ring 131. It is done by.

The cam groove 142 formed in the drive plate 14 is a closed curve, and is a curve such that the position of the top dead center of the piston 31 does not always change even when the fulcrum pin 16 moves in the cam groove 142. The thrust force acting on the main shaft 13 when compressing gas is a thrust bearing 42 provided between the drive plate 14 and the front housing 1, and the radial force acting on the main shaft 13 is based on the front housing 1 and the cylinder block. 2 are supported by radial bearings 19 and 18, respectively.

FIG. 2 shows a guide plate 51 made of a solid lubricant and mounted in a guide groove 28 provided on the inner peripheral portion of the front housing 1. Guide plate 51 in this embodiment
Has a surface 52 composed mainly of a synthetic resin. Third
The figure is a partial sectional view of the piston support guide mechanism when the guide plate 51 is mounted. In a car air conditioner, the rotational speed of the compressor may reach up to about 8000 r / m, in which case the sliding speed of the slide shoe 29 is the highest.
The speed is as high as 16m / s. Therefore, when the sliding portion is insufficiently lubricated, for example, at the time of startup in a state where the sliding portion is washed by the liquid refrigerant, at the time of high-speed and high-pressure operation, and at the time of operation with too little refrigerant, the slide shoe 29 is not used. There is a problem that image sticking occurs between the guide groove and the guide groove. Furthermore, since the current Freon 12 is subject to regulation by the Freon regulation, it is currently effective to shift to Freon 134a as an alternative Freon. However, since Freon 134a does not contain chlorine in its molecule, self-lubricating properties
It is clear that 12 is considerably inferior. In addition, the current mineral oil cannot be used as a refrigerating machine oil because of its compatibility, and synthetic oils such as PAG (polyalkylene glycol) having a lower pressure viscosity index than mineral oil have to be used as an alternative refrigerating machine oil. It is expected that the sliding condition will be considerably worse than the current situation, and that the compressor will be unable to move due to the seizure of the sliding portion.

On the other hand, when the guide plate 51 is mounted in the guide groove 28, the slide shoe 29
Slides on the surface 52 mainly composed of synthetic resin formed on the inner peripheral surface of the, so that no seizure occurs even when the sliding portion is insufficiently lubricated. This is evident from the results of the boundary lubrication friction sliding test with SKD11 as shown in FIG. 4. The guide plate material of the system has a seizure-resistant surface pressure value twice or more as large as that. Also,
Due to the excellent self-lubricating property of the synthetic resin, the coefficient of friction of the sliding portion is reduced, thereby lowering the driving torque of the compressor, thereby improving the overall adiabatic efficiency of the compressor, that is, reducing the load on the engine. be able to. In the present embodiment, the convex bottom of the guide plate 51 plays a role of preventing rotation of the guide groove 28. As for the synthetic resin as the main component, almost the same results were obtained with polyacetal resin, ketone resin and imide resin in addition to the tetrafluoroethylene resin. These synthetic resins have a structure with a sintered body layer of Pb, Sn, etc. inside, or have a surface eutectoidized by adding other solid lubricants such as graphite to the synthetic resin to further seizure resistance. It was confirmed that the wear resistance was improved.

One example is shown in FIG. In the figure, reference numeral 61 denotes a synthetic resin containing Pb as an additive. 62 is a bronze sintered layer. In addition to bronze, phosphor bronze or lead bronze may be used. The chemical composition (% by weight) shown in Table 1 is preferred. 63 is a backing metal made of cold rolled steel (SPCC). The composition (% by weight) is preferably as shown in Table 2.

Further, the surface of the slide shoe 29, which is a mating member, slides at least between the guide plate 51 and the surface receiving friction, the surface roughness is preferably Rmax 1 μm or less, and when it is more than Rmax, the amount of friction tends to increase.

In the above embodiment, the guide plate 51 is integral, but as shown in FIGS. 6 and 7, the guide plates 51 are divided into left and right structures 51 (a) and 51 (b), 52 (a) and 52 (b). ). In that case, it is not necessary to be symmetrical.

Although the embodiment shown in FIG. 1 is a variable stroke swash plate type compressor, it goes without saying that the present invention is also effective for a fixed stroke swash plate type compressor.

〔The invention's effect〕

As described above, according to the present invention, in the piston support guide mechanism, the wear resistance, seizure resistance, and sliding characteristics are improved, so that a highly durable, highly reliable slope that can cope with CFC regulations. A plate type compressor can be provided.

[Brief description of the drawings]

1 is a block diagram of a variable stroke swash plate type compressor according to one embodiment of the present invention, FIG. 2 is a perspective view of a guide plate, FIG. 3 is a cross-sectional view taken along the line I-II of FIG. 1, and FIG. FIG. 5 is a view showing the results of a lubrication friction sliding test, FIG. 5 is a cross-sectional view of a main part of one embodiment of a guide plate, and FIGS. 6 and 7 are cross-sectional views taken along the line I-II of FIG. is there. 1 ... front housing, 2 ... cylinder block, 12 ... swash plate, 13 ... spindle, 21 ... piston support, 26 ... guide pin, 27 ... slide ball, 28 ... guide groove, 29 ... Slide shoe, 51 …… Guide plate.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideki Machimura 2520, Oaza, Kata, Ibaraki Pref. Sawa Plant, Hitachi, Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) F04B 27 / 08

Claims (4)

(57) [Claims] 1. A housing made of an aluminum alloy, a drive shaft rotatably supported in the housing, a swash plate rotatably mounted around an axis perpendicular to the drive shaft, and a piston. A piston support that supports a rod and swings in accordance with the inclination angle of the swash plate, a bearing portion projecting in a radial direction of the piston support, and a housing inner peripheral portion formed parallel to a drive shaft. A swash plate type compressor having a guide groove fitted with a bearing, wherein a guide plate made of a solid lubricant is provided between the bearing and the bearing in the guide groove. 2. A housing having a crank chamber, a suction space and a discharge space therein, formed of an aluminum alloy, a drive shaft rotatably supported in the housing,
A plurality of cylinders arranged in the circumferential direction with the drive shaft as the center and the axis parallel to the drive shaft, pistons respectively reciprocally fitted to the cylinders, and around an axis perpendicular to the drive shaft. A swash plate rotatably mounted, rods fixed to the piston, a piston support supporting each rod and performing a swinging motion in accordance with the inclination angle of the swash plate, and a diameter of the piston support. A guide pin fixed in the same direction, a slide ball reciprocally and rotatably fitted to the guide pin, a slide shoe rotatably fitted into the slide ball inside the guide pin, and driven by the inner peripheral portion of the housing. A guide groove formed in parallel with the axial direction and having a cylindrical groove shape, the slide shoe being mounted to be rotatable and slidable in the guide groove, and the swash plate being inclined with respect to the drive shaft. A swash plate type compressor in which the slide shoe is fitted into the guide groove when the piston is reciprocated at a stroke corresponding to the degree, thereby suppressing the movement of the piston support in the rotation direction of the drive shaft. A swash plate type compressor, wherein a guide plate having at least a sliding surface made of a solid lubricant is provided between a sliding portion between the inside and the slide shoe. 3. The swash plate compressor according to claim 1, wherein the solid lubricant comprises a synthetic resin, and the synthetic resin is an ethylene tetrafluoride resin, a polyacetal resin, a ketone resin or an imide resin. 4. A swash plate compressor according to claim 2, wherein the slide shoe is formed of an iron-based material, and at least a sliding surface with the guide plate has a surface roughness of 1 μm or less in Rmax.