Swash plate type compressor

The present invention relates to a swash plate type compressor used for a vehicle air conditioner, and the like.

Japanese Patent Application Publication No. 2001-317453 discloses a swash plate type compressor in which a shoe is interposed between a swash plate connected to a drive shaft driven to rotate and a reciprocable piston. In the swash plate type compressor, the swash plate has a smooth convex curved surface formed on an axial end faces of the swash plate on which the shoes slide with an extremely large radius of curvature. A wedge-shaped clearance is provided between the convex curved surface of the swash plate and the plane surface of the shoe. Lubricating oil is supplied through such clearance to sliding surfaces of the swash plate and the shoes, thus improving the sliding characteristics between the swash plate and the shoes, and reducing abrasion occurring during sliding.

Japanese Patent Application Publication No. 2001-317453 discloses a typical swash plate type variable displacement compressor wherein the inclination angle of the swash plate relative to the drive shaft is varied to control the displacement of the compressor. When the compressor is required to be operated at the maximum displacement, the inclination angle of the swash plate is increased, and the reciprocating stroke length of the piston is increased, accordingly. As a result, reciprocating inertia force of the shoe disposed on the front side of the swash plate or on the far side of the swash plate from the cylinder bore is increased. This reciprocating inertia force acting on the shoe becomes maximum when the shoe contacts with the swash plate at the bottom dead center of the swash plate. FIG. 10 schematically illustrates a state wherein the swash plate 50 is positioned at the maximum inclination angle thereof, and the swash plate 50 is in contact at the bottom dead center thereof with the shoe 51A. As shown in FIG. 10, the reciprocating inertia force F acting on the shoe 51A in arrow direction (or leftward in FIG. 10) causes a slight clearance H to be formed between the plane surface 51C of the shoe 51A and the sliding surface 50A of the swash plate 50. The plane surface 51C of the shoe 51A is in edge contact with the edge 50B of the swash plate 50 at and adjacent to the bottom dead center thereof. In this state, the edge 50B of the swash plate 50 also receives a reaction force against suction force acting so as to urge the shoe 51A against the swash plate 50, as well as a normal force acting so as to urge the swash plate 50 against the shoe 51A. Thus, a load applied to the edge 50B becomes maximum. Then, the contact pressure applied to the plane surface 51C of the shoe 51A that is in contact with the edge 50B becomes also maximum. As a result, the plane surface 51C of the shoe 51A or the edge 50B of the swash plate 50 is abraded, thereby producing abrasion powder. Abrasion powder mixed in refrigerant gas deteriorates the performance of the compressor. Japanese Patent Application Publication No. 2001-317453 refers to a swash plate having a smooth convex curved surface on axial end faces thereof with an extremely large radius of curvature. However, no reference is made by Publication to an edge between the convex curved surface and the outer peripheral surface of the swash plate at and adjacent to the bottom dead center thereof. It is noted that the slight clearance H between the plane surface 51C of the first shoe 51A and the sliding surface 50A of the swash plate 50 is shown exaggerated in FIG. 10 for the sake of understanding the problem underlying the present invention.

To solve the above problem, it may be contemplated that the swash plate is made with an increased outer diameter, so that the edge of the swash plate at and adjacent to the bottom dead center thereof may be out of contact with the shoe. However, if the outer diameter of the swash plate is increased, it is necessary to design the swash plate in consideration of harmful interference of the swash plate with a piston when the swash plate is positioned at the minimum inclination angle thereof. As a result, the compressor is made larger in size.

The present invention, which has been made in light of the above problems, is directed to a swash plate type compressor which may restrict the abrasion of an edge of the swash plate or a plane surface of a shoe that are located on the far side of the swash plate from the cylinder bore.

In accordance with an aspect of the present invention, a swash plate type compressor has a cylinder block, a drive shaft, a piston, a pair of first and second shoes and a swash plate. The cylinder block has a plurality of cylinder bores. The drive shaft is supported by the cylinder block. The piston is accommodated in the cylinder bore. The first and second shoes are accommodated in the piston. The swash plate is connected to the drive shaft so as to be rotated integrally with the drive shaft. The swash plate is connected to the piston through the first and second shoes. The swash plate rotates around the drive shaft, and moves between the top dead center and the bottom dead center of the swash plate thereby to reciprocate the piston. The swash plate has a first surface on the far side of the swash plate from the cylinder bore in slide contact with the first shoe and a second surface on the same side of the swash plate as the cylinder bore in slide contact with the second shoe. The swash plate has a first edge formed between the first surface and an outer peripheral surface of the swash plate and a second edge formed between the second surface and the outer peripheral surface of the swash plate. The swash plate has a curved surface formed on the first edge at and adjacent to the bottom dead center of the swash plate whose radius of curvature is larger than a radius of curvature of the surface of the second edge.

A swash plate type compressor has a cylinder block, a drive shaft, a piston, a pair of a first shoe and a second shoe and a swash plate. The cylinder block has a plurality of cylinder bores. The drive shaft is supported by the cylinder block. The piston is accommodated in the cylinder bore. The first and second shoes are accommodated in the piston. The swash plate is connected to the drive shaft so as to be rotated integrally with the drive shaft. The swash plate is connected to the piston through the first and second shoes. The swash plate rotates around the drive shaft, and moves between the top dead center and the bottom dead center of the swash plate thereby to reciprocate the piston. The swash plate has a first surface on the far side of the swash plate from the cylinder bore in slide contact with the first shoe and a second surface on the same side of the swash plate as the cylinder bore in slide contact with the second shoe. The swash plate has a first edge formed between the first surface and an outer peripheral surface of the swash plate and a second edge formed between the second surface and the outer peripheral surface of the swash plate. having a flat chamfered surface formed on the first edge at and adjacent to the bottom dead center of the swash plate. The swash plate has a coating layer formed on the first surface and the first edge whose thickness on the first edge at and adjacent to the bottom dead center of the swash plate is larger than the thickness on the first surface.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a longitudinal cross-sectional view showing a swash plate type compressor of a first preferred embodiment of the present invention;

FIG. 2 is a fragmentary enlarged cross-sectional view showing the swash plate of FIG. 1 in the bottom dead center thereof and in contact with a shoe;

FIG. 3 is a schematic view showing the swash plate of FIG. 1 as viewed from the front of the compressor;

FIG. 4 is a cross-sectional view taken along the line I-I of FIG. 3;

FIG. 5A is a schematic view showing the swash plate in the bottom dead center thereof and in contact with the shoe according to the first preferred embodiment;

FIG. 5B is a schematic view showing the swash plate in an intermediate position thereof between the top and bottom dead centers thereof and in contact with the shoe according to the first preferred embodiment;

FIG. 5C is a schematic view showing the swash plate in the top dead center thereof and in contact with the shoe according to the first preferred embodiment;

FIG. 6 is a cross-sectional view similar to FIG. 4, but showing a swash plate according to a second preferred embodiment;

Continue reading about Swash plate type compressor...
Full patent description for Swash plate type compressor

Brief Patent Description - Full Patent Description - Patent Application Claims

Click on the above for other options relating to this Swash plate type compressor patent application.
###


How KEYWORD MONITOR works... a FREE service from FreshPatents
1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored.
3. Each week you receive an email with patent applications related to your keywords.  
Start now! - Receive info on patent apps like Swash plate type compressor or other areas of interest.
###


Previous Patent Application:
Portable hybrid gas compressor
Next Patent Application:
Fuel pump
Industry Class:
Pumps

###

Design/code © 2009 FreshContext LLC/Freshpatents.com. Website Terms and Conditions - Also read: About this Page
Patent data source: patents published by the United States Patent and Trademark Office (USPTO)
Information published here is for research/educational purposes only (and in conjunction with our Keyword Monitor) and is not meant to be used in place of the full USPTO patent document/images or a comprehensive patent archive search. Complete official applications are on file at the USPTO and often contain additional data/images (Freshpatents is currently text-only). FreshPatents.com is not affiliated with or endorsed by the USPTO or firms/individuals or products/designs/ideas related to listed patents.

FreshPatents.com Support
Thank you for viewing the Swash plate type compressor patent info.
IP-related news and info


Results in 2.33401 seconds


Other interesting Feshpatents.com categories:
Computers:  Graphics ,  I/O ,  Processors ,  Dyn. Storage ,  Static Storage ,  Printers paws