Patent Grant
9004888
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-239642, filed Oct. 30, 2012, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a rotary compressor used for an air conditioner, for example.
2. Description of the Related Art
A rotary compressor which has the above-stated configurations has had a problem that after the annular pistons 125S, 125T revolve in the cylinders 521S, 521T and pass through the discharge ports 190S, 190T, in small spaces 538S, 538T surrounded by the cylinder inner walls 523S, 523T, the annular pistons 125S, 125T, and the vanes 127S, 127T, refrigerant gas which is not discharged from the discharge ports 190S, 190T is compressed resulting in over compression loss which causes decrease in compression effect and worsening of COP.
Conventionally, a closed compressor (rotary compressor) including a closed container and electric elements and compression elements contained in the closed container, the compression elements being composed of a cylinder having an actuation chamber inside the cylinder, a roller (annular piston) which rotates in the cylinder by an eccentric portion of a rotary shaft thereof, a vane which contacts with the roller and slides a guide groove provided in the cylinder so as to divide the actuation chamber of the cylinder into a compression chamber and a suction chamber, and a frame (end plate) which seals the actuation chamber of the cylinder, the frame being provided with a discharge port which communicates with the compression chamber of the cylinder, wherein the discharge port is located completely inside the compression chamber of the cylinder and shaped in a circle, a long hole, or a crescent which does not protrude inside of an inner circumferential edge of the roller, moreover, the roller is shaped in a cylinder or a cylinder whose end face portion at the discharge port side is thick is disclosed (for example, refer to Japanese Patent Application Laid-open No. 05-133363.)
Additionally, a closed rotary compressor enclosing a motor unit and a rotary compression mechanism connected to the motor unit via a rotary shaft in a closed case, the rotary compression mechanism including a cylinder which forms a cylinder chamber, first and second cover members provided on both end faces of the cylinder so as to cover the cylinder chamber, and a roller and a vane which separate the cylinder chamber interior into a compression chamber and a suction chamber, wherein a discharge port for discharging a refrigerant compressed in the cylinder chamber is provided in at least one of the first and second cover members, provided a cross sectional area of the compression chamber when the vane is in a lower dead position is B (m2) and a cross sectional area of the discharge port is C (m2), the discharge port is set so as to satisfy C/B≦0.15, and the length of the discharge port is set to be 3 mm or less, moreover, a proportion of area that the discharge port faces the cylinder chamber is set to be 87% or more of the cross sectional area of the discharge port, and the cylinder is not provided with a notch groove for refrigerant discharge, is disclosed (for example, refer to Japanese Patent Application Laid-open No. 2007-198319.)
However, according to the conventional art disclosed in Japanese Patent Application Laid-open No. 05-133363, since the discharge port is located completely inside the compression chamber of the cylinder and a discharge notch is not provided in the compression chamber of the cylinder, although it is possible to decrease re-expansion loss, after the roller passes through the discharge port, refrigerant gas which is not discharged is compressed resulting in over compression loss in a space surrounded by the inner wall of the cylinder, the roller, and the vane, and the high pressure refrigerant gas returns to the suction chamber side of low pressure, causing decrease in compression effect and worsening of COP, which must be the problem.
Moreover, according to the conventional art disclosed in Japanese Patent Application Laid-open No. 2007-198319, since the proportion of area that the discharge port faces the cylinder chamber is 87% or more of the cross sectional area of the discharge port, volume of the space surrounded by the inner wall of the cylinder, the roller, and the vane after the roller passes through the discharge port decreases compared with that of Japanese Patent Application Laid-open No. 05-133363 so that the over compression loss slightly decreases, but still, the compression effect decreases and the COP of the whole refrigeration cycle worsens.
The present invention has been made considering the above-stated matters and aims to decrease the over compression loss and improve the compression effect so as to obtain a rotary compressor with better COP.
It is an object of the present invention to at least partially solve the problems in the conventional technology. According to an aspect of the present invention, a rotary compressor comprises a compression unit that includes an annular cylinder including a suction port and a vane groove which are radially provided to a side portion thereof; an end plate which covers an end portion of the cylinder; an annular piston which is fitted into an eccentric portion of a rotary shaft rotated by a motor and revolves in the cylinder along a cylinder inner wall of the cylinder so as to form an actuation chamber between the cylinder inner wall and the annular piston; and a vane which protrudes into the actuation chamber from an inside of the vane groove provided in the cylinder so as to abut against the annular piston and divide the actuation chamber into a suction chamber and a compression chamber. A discharge port is provided in the end plate near the vane groove, the discharge port communicates with the compression chamber, and a part of the discharge port is located outside the cylinder inner wall; and a discharge groove is provided in the cylinder inner wall near the vane groove, the discharge groove communicates the compression chamber with the discharge port, and one side end portion of the discharge groove is located in an end portion of a wall portion of the vane groove on a compression chamber side.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
Hereafter, embodiments of the rotary compressor according to the present invention are described in detail with reference to the drawings. Note that, the invention is not limited by the embodiments.
First Embodiment
As illustrated in
A stator 111 of the motor 11 having a cylindrical form is fixed on the inner circumferential surface of the compressor casing 10 by shrink fit. A rotor 112 of the motor 11 is arranged inside the cylindrical stator 111 and fixed by shrink fit to a rotary shaft 15 which mechanically connects the motor 11 and the compression unit 12.
The compression unit 12 includes a first compression unit 12S, and a second compression unit 12T which is arranged in parallel with the first compression unit 12S and stacked above the first compression unit 12S. As illustrated in
As illustrated in
In the first and second cylinders 121S and 121T, the first and second vane grooves 128S, 128T which radially range the whole cylinder height from the first and second cylinder inner walls 123S, 123T are formed. In the first and second vane grooves 128S, 128T, tabular first and second vanes 127S, 127T are slidably fit, respectively.
As illustrated in
Additionally, at the first and second cylinders 121S, 121T, first and second pressure introduction passages 129S, 129T which communicate the back portions of the first and second vane grooves 128S, 128T with the inside of the compressor casing 10 via an opening portion R illustrated in
At the first and second cylinders 121S, 121T, first and second suction ports 135S, 135T which communicate the first and second suction chambers 131S, 131T with the outside are provided for inhaling refrigerant from the outside into the first and second suction chambers 131S, 131T.
Additionally, as illustrated in
At the lower end plate 160S, an auxiliary bearing portion 161S is formed. An auxiliary axis portion 151 of the rotary shaft 15 is rotatably supported by the auxiliary bearing portion 161S. At the upper end plate 160T, a main bearing portion 161T is formed. A main axis portion 153 of the rotary shaft 15 is rotatably supported by the main bearing portion 161T.
The rotary shaft 15 includes a first eccentric portion 152S and a second eccentric portion 152T whose phases are shifted by 180 degrees relative to each other so as to be eccentric. The first eccentric portion 152S is rotatably fit into the first annular piston 125S of the first compression unit 12S. The second eccentric portion 152T is rotatably fit into the second annular piston 125T of the second compression unit 12T.
When the rotary shaft 15 rotates, the first and second annular pistons 125S, 125T revolve in the counterclockwise direction in
As illustrated in
The lower muffler chamber 180S is a chamber which is annularly formed, and a portion of a communication passage which communicates the discharge side of the first compression unit 12S with the inside of an upper muffler chamber 180T through a refrigerant passage 136 (refer to the
As illustrated in
The first cylinder 121S, the lower end plate 160S, the lower muffler cover 170S, the second cylinder 121T, the upper end plate 160T, the upper muffler cover 170T, and the mid-division panel 140 are integrally fastened by a plurality of through bolts 175 and the like. In the compression unit 12 which is integrally fastened by the through bolts 175 and the like, the outer circumferential portion of the upper end plate 160T is secured to the compressor casing 10 by spot welding so as to fix the compression unit 12 to the compressor casing 10.
On the outer circumferential wall of the cylindrical compressor casing 10, axially spaced first and second through holes 101, 102, from bottom to top, are provided for passing first and second suction pipes 104, 105. Additionally, on the outer portion of the compressor casing 10, an accumulator 25 composed of an independent cylindrical closed container is held by an accumulator holder 252 and an accumulator band 253.
To the center of the ceiling portion of the accumulator 25, a system connecting pipe 255 to be connected with an evaporator of the refrigeration cycle is connected. To a bottom through hole 257 provided on the bottom portion of the accumulator 25, first and second low pressure communication pipes 31S, 31T, of which one end extends to the upper portion of the interior of the accumulator 25 and the other end is connected to the other end of the first and second suction pipes 104, 105, are connected.
The first and second low pressure communication pipes 31S, 31T, which guide the low pressure refrigerant of the refrigeration cycle to the first and second compression units 12S, 12T through the accumulator 25, are connected to the first and second suction ports 135S, 135T (refer to
To the ceiling portion of the compressor casing 10, a discharge pipe 107 as a discharge portion which connects with the refrigerant cycle so as to discharge high pressure refrigerant gas to the condenser side of the refrigeration cycle. Namely, the first and second discharge ports 190S, 190T are connected to the condenser of the refrigeration cycle.
In the compressor casing 10, lubrication oil is enclosed approximately to the level of the second cylinder 121T. In addition, the lubrication oil is absorbed from a feed oil pipe 16 attached to the lower end portion of the rotary shaft 15 by a wing pump (not illustrated) inserted into the lower portion of the rotary shaft 15, and circulates in the compression unit 12 so as to lubricate sliding parts as well as sealing tiny gaps of the compression unit 12.
Next, a characteristic configuration of the rotary compressor 1 of the first embodiment is described, referring to
On the first and second compression chambers 133S, 133T side of the lower end plate 160S and the upper end plate 160T, the first and second discharge ports 190S, 190T which communicate with the first and second compression chambers 133S, 133T are provided near the first and second vane grooves 128S, 128T. Parts of the first and second discharge ports 190S, 190T are located outside the first and second cylinder inner walls 123S, 123T.
Near the first and second vane grooves 128S, 128T of the first and second cylinder inner walls 123S, 123T, first and second discharge grooves 137S, 137T are formed. The first and second discharge grooves 137S, 137T communicate the first and second compression chambers 133S, 133T with the first and second discharge ports 190S, 190T. One side end portions of the first and second discharge grooves 137S, 137T are located in end portions 128Sa, 128Ta of the wall portions of the first and second vane grooves 128S, 128T on the compression chamber side.
The first and second discharge grooves 137S, 137T are formed in a semicircular shape (or a semicircular cone shape) with a curvature radius R2 which is equal or approximate to a radius R1 of the first and second discharge ports 190S, 190T (0.9R1≦R2≦1.1R1, for example), and the semicircular shape inclines in the manner that a depth thereof becomes deeper as a position thereof approaches the lower and upper end plates 160S, 160T. The center of the curvature radius R2 is formed so as to be offset by a predetermined angle α (five degrees in the first embodiment) from the center of the first and second discharge ports 190S, 190T to the first and second vane grooves 128S, 128T side. As illustrated in
In the rotary compressor 1 of the embodiment, even after the first and second annular pistons 125S, 125T thereof revolve in the counterclockwise direction, the contact point between the first and second annular pistons 125S, 125T and the first and second cylinder inner walls 123S, 123T approaches the first and second vane grooves 128S, 128T, and the first and second annular pistons 125S, 125T completely cover the first and second discharge ports 190S, 190T, the first and second discharge grooves 137S, 137T communicate first and second small spaces 138S, 138T (refer to
Second Embodiment
Next, a characteristic configuration of the rotary compressor 1 of a second embodiment is described, referring to
As illustrated in
Near the first and second vane grooves 128S, 128T of the first and second cylinder inner walls 123S, 123T, first and second discharge grooves 237S, 237T are formed. The first and second discharge grooves 237S, 237T communicate the first and second compression chambers 133S, 133T with the first and second discharge ports 190S, 190T. One side end portions thereof are located in end portions 128Sa, 128Ta of the wall portions of the first and second vane grooves 128S, 128T on the compression chamber side.
The first and second discharge grooves 237S, 237T are formed in a semicircular shape (or a semicircular cone shape) with a curvature radius R3 which is larger than a radius R1 of the first and second discharge ports 190S, 190T, and the semicircular shape inclines in the manner that a depth thereof becomes deeper as a position thereof approaches the lower and upper end plates 160S, 160T. The first and second discharge grooves 237S, 237T communicate with the majority of the part, which is located outside the first and second cylinder inner walls 123S, 123T, of the first and second discharge ports 190S, 190T.
In the rotary compressor 1 of the second embodiment, even after the first and second annular pistons 125S, 125T thereof revolve in the counterclockwise direction, the contact point between the first and second annular pistons 125S, 125T and the first and second cylinder inner walls 123S, 123T approaches the first and second vane grooves 128S, 128T, and the first and second annular pistons 125S, 125T completely cover the first and second discharge ports 190S, 190T, the first and second discharge grooves 237S, 237T communicate first and second small spaces 138S, 138T (refer to
Since the first and second discharge grooves 237S, 237T of the second embodiment communicate with the majority of the part, which is located outside the first and second cylinder inner walls 123S, 123T, of the first and second discharge ports 190S, 190T, flow resistance is low when relieving the compressed refrigerant gas in the first and second small spaces 138S, 138T to the first and second discharge ports 190S, 190T.
Note that, while the embodiments of the two cylinder type rotary compressor have been described in the first and second embodiments, the rotary compressor of the present invention can be applied to a single cylinder type rotary compressor and a two stage compression type rotary compressor.
The present invention provides the benefit of obtaining a rotary compressor whose over compression loss is low, compression effect is high, and COP of the whole refrigeration cycle thereof is high.
Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-239642 | Oct 2012 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4537567 | Kawaguchi et al. | Aug 1985 | A |
| 5823755 | Wilson et al. | Oct 1998 | A |
| 6042351 | Bushnell et al. | Mar 2000 | A |
| Number | Date | Country |
|---|---|---|
| 59158396 | Sep 1984 | JP |
| 05-133363 | May 1993 | JP |
| 2007-198319 | Aug 2007 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20140119968 A1 | May 2014 | US |
