US3516766A - Rotary compressor - Google Patents

Description

June 23, 1970 TUNEQ MQNDEN ETAL I 3,516,766

ROTARY COMPRESSOR Filed July 10, 1958 2 Sheets-Sheet 1 FIG. I

INVENTOR) June 23, 1970 TUNEO .MONDEN ETAL ROTARY COMPRESSOR 2 Sheets-Sheet 2 Filed July 10, 1966 FIG. 3

FIG. 4

INVENTORS United States Patent O US. Cl. 41863 1 Claim ABSTRACT OF THE DISCLOSURE In a rotary compressor wherein a rotor supported by an eccentric is caused to roll along the inner periphery of a hollow cylinder, a pair of annular grooves extending axially from the opposite end surfaces of the rotor are provided near the inner periphery of the rotor to permit elastic deformation of the rotor periphery.

BACKGROUND OF THE INVENTION This invention relates to a rotary compressor and more particularly to a motor driven rotary compressor for air conditioners and contained in a hermetically sealed casing.

This type of motor compressor comprising a driving motor inserted in the upper portion of the sealed casing, a flange supporting the shaft of the motor and a compressor located beneath the flange. The compressor comprises a cylinder, a rotor mounted on an eccentric of the motor shaft to eccentrically roll along the inner surface of the cylinder and a slide blade contained in a slot of the cylinder and urged against the outer periphery of the rotor by means of a spring whereby upon rotation of the rotor, gaseous refrigerant is sucked into a low pressure chamber in the cylinder, compressed and is then discharged into a condenser from a high pressure cham ber. As the interior of the cylinder is divided into the low and high pressure chambers by the slide blade the contact surface between the inner surface and the outer surface of the eccentric would not become a uniform surface contact but instead the load concentrates to some portion causing excessive wear thereof. Operation over a long period under such concentrated load not only decreases the efliciency of gas compression but also applies an overload to the driving motor.

In accordance with this invention these troubles are eliminated by providing a pair of annular grooves axially extending from the opposite end surfaces of the rotor near the inner periphery thereof thus permitting elastic deformation thereof.

The outer diameter of the eccentric may be reduced at the central portion of the portion opposing the solid portion of the rotor between the bottoms of the annular grooves.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal section of a motor compressor embodying this invention;

FIG. 2 shows a partial cross-sectional view of the compressor shown in FIG. 1 taken along a line IIII.

FIG. 3 is a partial view, partly in section to show the concentrated load at the contacting surface between the eccentric and the rotor of a prior art compressor;

FIG. 4 is a view, partly in section, of the rotor and eccentric showing the distribution of said pressure;

FIG. 5 is a cross-sectional view, taken along a line V--V in FIG. 4 and viewed in the direction of arrows; and

3,516,766 Patented June 23, 1970 FIG. 6 is an enlarged view to show the elastic deformation of contacting surface between the eccentric and rotor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, a rotary compressor embodying this invention is shown as comprising a cylindrical hermetically sealed casing 10 in which is inserted a stator 12 of a motor 13. The stator 12 is provided with a winding 17 to drive a rotor 11 having a shaft 18 journaled by a frame 19 also force fit in the sealed casing. A cylinder 21 of the compressor is clamped between the lower surface 19a of frame 19 and a lower end plate 22. In a cylinder cavity 23 are contained an eccentric 14 of the motor shaft 18 and a rotor 15 encircling the eccentric 14. A slide blade 24 is received in a slot cut in the cylinder 21, which is normally urged against the periphery of the rotor by means of a spring 25. Cylinder 21 has a suction port 30 communicating with a suction perforation 26, an exhaust port 31 which is normally closed by a discharge valve 32 and a high pressure discharge chamber 33 communicating with a condenser through a discharge perforation 27. As shown in FIG. 2 the lower end plate 22 is connected to the frame 19 by bolts 29 extending through bolt holes 28.

With the prior construction, due to the above-mentioned side pressure P, the contact pressure between the rotor and the eccentric is not uniform as diagrammatically shown in FIG. 3. Thus the load is the highest at a point C causing undesirable wear at this point and undesirable overload of the driving motor.

As shown in FIGS. 4 and 5, according to this invention, outside diameter of the eccentric 14 is reduced about 0.1 to 1 mm., at the central portion over a length of about Vs of the total axial length and the rotor is provided with annular grooves 103 near its inner periphery, said annular grooves extending from opposite end surfaces of the rotor towards the axial center thereof.

In FIG. 4, the reduced portion of the outside diameter of the eccentric 14 is shown by the reference numeral 141, portions adjacent to the bottom of said annular grooves 103 and said reduced portion 141 of the eccentric 14 being axially overlapped with respect to each other. In the arrangement shown, the eccentric 14 contacts only thin, inner peripheral walls 106 of the rotor 15 which are disposed adjacent to a pair of grooves and, therefore, the side pressure applied to the eccentric is uniformly distributed as illustrated by arrows in FIG. 4.

The operation of the novel compressor is a follows: When the rotor 15 is rotated by the electric motor to compress the gaseous refrigerant, load is concentrated at a point C shown in FIG. 6, by the side pressure acting upon the rotor 15 to deform the rotor as shown by GP, thus causing non-uniform contact between the rotor and the eccentric. However, annular grooves 103 permits elastic deformation of thin peripheral walls 106 between the annular grooves 103 and the inner periphery of the rotor thus causing the contact surface of the rotor to assume a position shown by CO thus assuring uniform distribution of the side pressure in the eccentric 14. Thus the undesirable effect of side pressure is alleviated to reduce local wear and smooth operation over a long time.

Since the solid portion 105 between the bottoms of annular grooves 103 does not undergo elastic deformation, the diameter of the eccentric opposing this portion is reduced to make more effective the elastic deformation. However, it will be clear that elastic deformation can be permitted to occur without reducing the diameter of the central portion of the eccentric. Further, it is clear that the pair of annular grooves 103 may be unsymmetrical.

While the invention has been shown and described in terms of a preferred embodiment it should be understood that many alterations and modifications will occur to those skilled in the art without departing from the true scope and spirit of the invention as defined in the appended claim.

What is claimed is:

1. In a rotary compressor comprising a cylinder including an inner peripheral wall; an eccentric, eccentrically disposed in said cylinder; a rotor, slidably contacting said inner peripheral wall and rotatably force fitted around the eccentric, and a slidable blade normally urged against said rotor; the improvement therein in that a pair of annular grooves are provided near the inner periphery of said rotor and extend axially from the opposite end surfaces of 1.)

said rotor; and at the central portion of said eccentric,

4 the outer diameter is such as to define a reduced portion thereat.

References Cited UNITED STATES PATENTS WILLIAM L. FREEH, Primary Examiner W. J. GOODLIN, Assistant Examiner U.S. Cl. X.R. 417424; 41881

Images