Expansible chamber devices – Relatively movable working members – Interconnected with common rotatable shaft
Reexamination Certificate
1997-11-20
2001-09-18
Nguyen, Hoang (Department: 3748)
Expansible chamber devices
Relatively movable working members
Interconnected with common rotatable shaft
C092S012200, C074S060000, C417S269000
Reexamination Certificate
active
06289785
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a swash plate type compressor and, more particularly, to improved lubricating performance of the sliding contact surfaces of a swash plate and a shoe of the compressor.
2. Description of the Related Art
Hitherto, swash plate type compressors have been used as an apparatus for compressing refrigerant gas in automotive climate control systems. Such swash plate type compressors are equipped with a cylinder block assembly which has a plurality of cylinder bores provided parallel to a drive shaft; a swash plate secured to the drive shaft so as to be rotated by the drive shaft in the cylinder block assembly; pistons slidably fitted to reciprocate in the cylinder bores to compress the refrigerant gas; and shoes which are provided between the pistons and the swash plate which reciprocate the pistons in response to the rotation of the swash plate.
In the above swash plate type compressor, high load and high sliding speed regularly act on the sliding contact surfaces of the swash plate and the shoes. Accordingly the sliding contact surfaces of the swash plate and the shoes are apt to become dry due to any insufficient supply of lubricating oil. This poses a problem especially where aluminum or an aluminum alloy is used as the base metal of the swash plate because of its light weight.
To solve this problem, as disclosed in Japanese Patent Application Laid-open No. 60-22080, at least the swash plate or the shoes employ aluminum or an aluminum alloy as the base metal with the sliding contact surface thereof coated with an alloy which contains molybdenum disulfide (MoS2) as the main component. Another solution has been proposed in Japanese Patent Application Laid-open No. 2-130272, in which the surface of the swash plate is plated with an alloy, in which tin is the main component, to form a surface treating layer.
In the former solution, although the solid lubricant layer, containing molybdenum disulfide as the main component, exhibits good lubricating performance, it has such shortcomings as poor wear resistance and a short service life.
The latter solution provides a high degree of hardness and accordingly good wear resistance; however, it is disadvantageous in that the lubricating performance is not as high as that of the former solution.
SUMMARY OF THE INVENTION
The present invention has been made with a view toward solving the problems with the prior art described above, and it is an object of the invention to improve the lubricating performance of the sliding contact surfaces of a swash plate and a shoe and to maintain the improved lubricating performance for a long period of time.
To this end, according to the present invention, there is provided a swash plate type compressor equipped with: a cylinder block assembly which has a plurality of cylinder bores provided parallel to a drive shaft; the drive shaft rotatably held in the cylinder block assembly; a swash plate which is rotatably disposed to the drive shaft in the cylinder block assembly; pistons slidably disposed in the cylinder bores; and shoes which are slidably provided between the pistons and the swash plate which reciprocates the pistons in response to the rotation of the swash plate; wherein the swash plate and the shoes are in sliding contact, a sliding contact surface of the swash plate or the shoes being covered with a plating layer composed of tin or an alloy containing tin as the main component, and the plating layer being covered with a coating layer composed of molybdenum disulfide as the main component which serves as a solid lubricant layer.
The plating layer composed of tin or an alloy containing tin as the main component refers to an alloy plating layer in which the weight of tin is greater than the weight of the other alloy components. The coating layer composed of molybdenum disulfide as the main component refers to an alloy coating layer in which the weight of molybdenum disulfide is the greatest among the contained components, except for a binder.
With this arrangement, the coating layer, which serves as a solid lubricant layer, is formed on the surface of the swash plate on the shoes which make sliding contact, so that good lubricating performance can be achieved. The coating layer has the shortcoming of poor wear resistance; hence, it is possible that the coating layer may wear or peel after an extended period of use because of the high sliding contact load applied when the pistons reach their top dead centers. However, the plating layer is applied under the coating layer; the plating layer exhibits high wear resistance, and the plating layer and the molybdenum disulfide in the coating layer have good affinity. Further, the sliding contact surfaces of the swash plate and the shoes are periodically subjected to high and low sliding contact load. Hence, when the sliding contact load decreases intermittently, frictional heat causes the coating layer to flow to the portion which has worn or peeled. Thus, the portion of the plating layer which has been exposed due to wearing or peeling, is re-covered and repaired by the coating layer as a solid lubricant layer.
As set forth above, whenever the sliding contact load decreases, the coating layer is repaired, permitting high lubricating performance to be maintained for a long period of time.
Thus, providing the coating layer mainly composed of molybdenum disulfide on the plating layer composed of tin or the alloy, which contains tin as the main component, improves its adhesion to the base metal. The coating layer also has a self-repairing function. This enables long lasting high lubricating performance.
In a preferred form of the invention, the swash plate is made of aluminum or an aluminum alloy, and the sliding contact surface of the swash plate is provided with the plating layer as a surface treating layer.
With this arrangement, the adhesion between the plating layer and the base metal is improved and the service life of the plating layer is extended, thus enabling high lubricating performance to be maintained for a longer period of time.
In another preferred form of the invention, the aforesaid surface of the swash plate is arranged so that primary crystal silicon particles are exposed. The plating layer composed of tin or an alloy containing tin as the main component is provided as the surface treating layer on the exposed surface of the swash plate.
With this arrangement, adhesion between the plating layer and the base metal is further improved, allowing high lubricating performance to be maintained for an even longer period of time.
In another preferred form of the invention, the coating layer on a plating layer contains graphite as an additional component.
With this arrangement, the coating layer provides better lubrication between the surface of the swash plate and the shoes than a coating layer which, excepting for a binder, is composed only of molybdenum disulfide.
REFERENCES:
patent: 4037522 (1977-07-01), Inoshita et al.
patent: 4568252 (1986-02-01), Hattori et al.
patent: 4934442 (1990-06-01), Futamura et al.
patent: 5056417 (1991-10-01), Kato et al.
patent: 5057274 (1991-10-01), Futamura et al.
patent: 5655432 (1997-08-01), Wilkosz et al.
patent: 5845560 (1998-12-01), Nagata et al.
patent: 5851320 (1998-12-01), Auran et al.
patent: 5875702 (1999-03-01), Kawagoe et al.
patent: 0 679 809 (1995-11-01), None
patent: 6-022080 (1985-02-01), None
patent: 61-291941 (1986-12-01), None
patent: 2-130272 (1990-05-01), None
patent: 8-199327 (1996-08-01), None
patent: PCT/JP96/01293 (1996-11-01), None
Patent Abstracts of Japan Publication No. 10205442, published Aug. 4, 1998.
Patent Abstracts of Japan Publication No. 08199327, published Aug. 6, 1996.
Patent Abstracts of Japan Publication No. 05071528, published Mar. 23, 1993.
Ikeda Hayato
Kato Masafumi
Kato Takayuki
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan , LLP
Nguyen Hoang
LandOfFree
Swash plate type compressor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Swash plate type compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Swash plate type compressor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2524831