WO2008047515A1

WO2008047515A1 - Compressor

Info

Publication number: WO2008047515A1
Application number: PCT/JP2007/067345
Authority: WO
Inventors: Kazuhiro Yokota
Original assignee: Panasonic Corporation
Priority date: 2006-09-27
Filing date: 2007-08-30
Publication date: 2008-04-24
Also published as: CN101356368A; JP2009509076A

Abstract

A compressor includes a cylinder having an opening end and an inner wall, a piston inserted in the cylinder and reciprocating in the cylinder, a valve plate for sealing the opening end of the cylinder and having a suction port and a discharge port provided therein, a suction reed held between the opening end of the cylinder and the valve plate for opening and closing the suction port, and a gasket provided between the opening end of the cylinder and the suction reed. The suction reed includes a head for opening and closing the suction port, an arm elastically supporting the head, and a base connected to the arm and held between the opening end of the cylinder and the valve plate. The base is held at a border positioned away from the inner wall of the cylinder towards outside of the cylinder. The border has a shape coinciding with an isodynamic stress line of a bending stress produced on the base of the suction reed. The suction reed of the compressor hardly breaks and thus has high reliability.

Description

DESCRIPTION

COMPRESSOR

TECHNICAL FIELD

The present invention relates to a compressor for use in a cooling apparatus, such as a refrigerator, an air conditioner, or a freezing and refrigerating system.

BACKGROUND ART

Fig. 5 is a schematic view of a conventional compressor 501 disclosed in Japanese Patent Laid-Open Publication No.2001-221161. Fig. 6 is a cross sectional view of the conventional compressor 501 taken along line 6-6 shown in Fig. 5. A cylinder 22 is provided in a cylinder block 1 and allows a piston 3 to reciprocate therein. A valve plate 44 is placed at an opening end of the cylinder 22 for sealing the opening and. A suction reed 5 made of a thin plate of spring steel is held between the valve plate 44 and the opening end of the cylinder 22. A gasket 66 is provided between the suction reed 5 and the opening end of the cylinder 22. The valve plate 44 has a suction port 7 and a discharge port 8 provided therein. The suction reed 5 includes a head 9 for closing and opening the suction port 7, a tongue 10 projecting from a distal end of the head 9, an arm 11 elastically supporting the head 9, and a base 12 for securing the arm 11 to the cylinder 22. More particularly, the suction reed 5 is fixed to the gasket 66 at the base 12. The suction reed 5 includes portions 5A and 5B separated at a border 13. The portion 5A moves when the suction reed 5 is displaced. The portion 5B does not move when the suction reed 5 is displaced. A stopper 14 is provided in an inner wall of the cylinder 22 for stopping the tongue 10 of the suction reed 5.

An operation of the conventional compressor 501 will be described below. The piston 3 reciprocates in the cylinder 22. During a suction stroke, the pressure in the cylinder 22 decreases and causes the suction reed

5 to open the suction port 7, thereby introducing an refrigerant into the cylinder 22 the suction port 7. During a discharge stroke, the pressure in the cylinder increases and causes the suction reed 5 to close the suction port

7, thereby allowing the refrigerant to discharge from the discharge port 8 to outside.

When the suction reed 5 opens the suction port 7, the stopper 14 contacts the tongue 10 and restricts the deforming of the suction reed 5 to control a stress on the suction reed 5.

In the conventional compressor 501, when the suction reed 5 is excessively deflected due to backward flow of liquid, a stress may concentrate at both ends of the border 13, thereby causing the suction reed 5 to break.

SUMMARY OF THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view of a compressor according to Exemplary Embodiment 1 of the present invention.

Fig. 2 is a cross sectional view of the compressor taken along line 2-2 shown in Fig. 1.

Fig. 3 is a schematic view of a compressor according to Exemplary Embodiment 2 of the invention. Fig. 4 is a cross sectional view of the compressor taken along the line

4-4 shown in Fig. 3.

Fig. 5 is a schematic view of a conventional compressor. Fig. 6 is a cross sectional view of the conventional compressor taken along the line 6-6 shown in Fig. 5.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS EXEMPLARY EMBODIMENT 1

Fig. 1 is a schematic view of a compressor 1001 according to Exemplary

Embodiment 1 of the present invention. Fig. 2 is a cross sectional view of the compressor 1001 taken along a line 2-2 shown in Fig. 1. A cylinder 102 having a cylindrical shape is provided in a cylinder block 101. A piston 103 inserted in the cylinder 102 reciprocates along an inner wall 102B of the cylinder 102. A valve plate 104 is placed at an opening end 102A of the cylinder 102 for sealing the opening end 102A. A suction reed 105 made of a thin plate of spring steel is supported between the valve plate 104 and a gasket 106. The gasket 106 is provided between the suction reed 105 and the opening end 102A of the cylinder 102. The suction reed 105 contacts the gasket 106. The gasket 106 contacts the opening end 102A of the cylinder 102. The valve plate 104 has a discharge port 108 and two suction ports 107 provided therein. The suction ports 107 have circular shapes. The suction reed 105 includes a head 109 for closing and opening the suction ports 107, an arm 111 elastically supporting the head 109, and a base 112 for securing the arm 111 to the cylinder 102. The gasket 106 is made of a sheet of paper coated with rubber material, and has a small elasticity.

The suction reed 105 deforms and is displaced as to open and close the suction ports 107. The suction reed 105 is held between the gasket 106 and the valve plate 104. The suction reed 105 has portions 105A and 105B. The portion 105A is displaced as to open and close the suction ports 107. The portion 105B contacts the gasket 106 and is not displaced. A border 113 is positioned at the border between the portions 105A and 105B of the suction reed 105 and separates the suction reed 105 into the portions 105A and 105B. The border 113 is located at the base 112 of the suction reed 105. The suction reed 105 extends between the two discharge ports 108.

The border 113 is set back from the inner wall 102B of the cylinder 102, i.e., is positioned away from the inner wall 102B of the cylinder 102 in a direction Tl directing outward from the cylinder 102. The base 112 is held at the border 113. The suction reed 105, upon sagging and deforming, has a stress distributed to produce isodynamic lines 120A to 120C. The border 113 has a shape coinciding with the isodynamic stress line 120C of a bending stress induced on the base 112. The border 113 shown in Fig. 2 has an arcuate shape.

An amount of setback, i.e., a distance Dl from the inner wall 102B to the border 113 of the cylinder 102 and a radius Rl of the arcuate shape are determined to prevent the suction reed 105 from contacting the opening end

102A of the cylinder 102 when the suction reed 105 is displaced by a maximum amount.

An operation of the compressor 1001 will be described below.

The piston 103 reciprocates in the cylinder 102, and decreases the pressure in the cylinder 102 during a suction stroke. This creates a difference between a pressure in the suction port 107 and a pressure in the cylinder 102, accordingly applying a force to the head 109 of the suction reed 105. Then, the arm 111 of the suction reed 105 deflects inward and opens with respect to the base 112 as a fulcrum, thus opening the suction port 107 and introducing the refrigerant into the cylinder 102. During a discharge stroke, the pressure in the cylinder 102 increases to cause the suction reed 105 to close the suction port 107, thereby allowing the refrigerant to flow out from the discharge port 108 via a discharge valve to outside of the cylinder 102. In order to increase the refrigerating capacity of the compressor 1001, the opening area of the suction port 107 is increased to reduce a suction resistance to the flow of the refrigerant. As the opening area of the suction port 107 becomes larger, the head 109 for opening and closing the suction port 107 necessarily has a larger size. If the arm 111 is excessively thin with respect to the large size of the head 109, the arm 111 may twist and break when the suction reed 105 deflects.

If the arm 111 has a width identical to that of the head 109, the suction reed 105 has an excessively large rigidity, accordingly reducing the amount of the deflection of the suction reed 105 and increasing the suction resistance. If the base 112 has a large width, the effective length of the portion 105A of the suction reed 105 which deflects becomes shorter, hence causing a stress to concentrate at both ends of the border 113 and breaking the base 112.

If the gasket 109 is merely set back from the inner wall 102B of the cylinder 102 in the direction Tl directing outside of the cylinder 102 to increase the effective length of the suction reed 105, the suction reed 105 may contact the opening end 102A of the cylinder 102, and may have the base 112 break. In order to avoid this, a portion of the opening end 102A of the cylinder 102 facing the base 112 of the suction reed 102 is provided with a slanting recess. This structure decreases the volume of a clearance, i.e., a space provided between the valve plate 104, the inner wall 102B of the cylinder 102, and the piston 103, accordingly decreasing the refrigerating capacity of the compressor 1001.

In the compressor 1001 according to this embodiment, the arm 111 has a width preventing the above twisting of the arm 111. The gasket 106 is set back away from the inner wall 102B of the cylinder 102 in the direction Tl directing towards the outside of the cylinder 102. The border 113 holding the base 112 has the shape coinciding with the isodynamic stress line 120C of a bending stress produced on the base 112, and has the arcuate shape according to this embodiment. This structure prevents the suction reed 105 from causing the bending stress to concentrate at a portion of the base 112, thus providing the compressor 1001 with the suction reed 105 hardly breaking and having high reliability.

In the compressor 1001, even when deflecting by the maximum amount, the suction reed 105 does not contact the opening end 102A of the cylinder 102, hence hardly deforming and hardly breaking.

The border 113 has the arcuate shape coinciding with the isodynamic stress line of the bending stress produced on the base 112 of the suction reed 105, and hence, minimizes a space between the inner wall 102B of the cylinder 102 and the border 113 of the suction reed 105, which is provided by setting back the border 113 from the inner wall 102B in the direction directing towards the outside of the cylinder 102. Accordingly, the volume of the clearance is minimized, and prevents the refrigerating capacity of the compressor 1001 from decreasing due to the increase of the volume of the clearance.

In the compressor 1001, the two circular suction ports 107 provide a large total opening area. A single circular suction port having a large opening area could reduce a suction resistance to the flow of the refrigerant. In this case, however, the stress produced on the head 109 of the suction reed 105 increases due to a difference between the pressure in the single suction port and the pressure in the cylinder 102 during a discharge stroke, and may cause the suction reed 105 to deform and break.

In the compressor 1001 according to this embodiment, the two circular suction ports 107 having small opening areas provide the large total opening area while reducing the stress produced on the head 109 of the suction reed 105. Accordingly, the compressor 1001 has the large refrigerating capacity and high reliability and prevents the suction reed 105 from breaking.

According to this embodiment, the gasket 106 is made of paper coated with rubber material. The gasket may be made of paper with no coating of rubber material or a strip of rubber material made of mixture of fiber, binder, and rubber. EXEMPLARY EMBODIMENT 2

Fig. 3 is a schematic view of a compressor 1002 according to Exemplary Embodiment 2 of the present invention. Fig. 4 is a cross sectional view of the compressor 1002 taken along a line 4-4 shown in Fig. 3. A cylinder 202 having a cylindrical shape is provided in a cylinder block 201. A piston 203 inserted in the cylinder 202 reciprocates along an inner wall 202B of the cylinder 202. A valve plate 204 is placed at an opening end 202A of the cylinder 202 for sealing the opening end 202A. A suction reed 205 made of a thin plate of spring steel is supported between the valve plate 204 and a gasket 206. The gasket 206 is provided between the suction reed 205 and the opening end 202A of the cylinder 202. The suction reed 205 contacts the gasket 206. The gasket 206 contacts the opening end 202A of the cylinder 202. The valve plate 204 has a discharge port 208 and a suction port 207 provided therein. The suction port 207 has a non-circular shape. The suction reed 205 includes a head 209 for closing and opening the suction port 207, a tongue 210 projecting from an end of the head 209, an arm 211 elastically supporting the head 209, and a base 212 for securing the arm 211 to the cylinder 202. The arm 211 has an aperture 211A provided therein. The gasket 206 is made of a sheet of paper coated with rubber material, and has a small elasticity.

The suction reed 205 deforms and is displaced as to open and close the suction port 207. The suction reed 205 is held between the gasket 206 and the valve plate 204. The suction reed 205 has portions 205A and 205B. The portion 205A is displaced as to open and close the suction port 207. The portion 205B contacts the gasket 206 and is not displaced. A border 213 is positioned at the border between the portions 205A and 205B of the suction reed 205 and separates the suction reed 205 into the portions 205A and 205B. The border 213 is located at the base 212 of the suction reed 205.

The border 213 is set back from the inner wall 202B of the cylinder 202, i.e., is positioned away from the inner wall 202B of the cylinder 202 in a direction T2 directing outward from the cylinder 202. The base 212 is held at the border 213. The suction reed 205, upon sagging and deforming, has a stress distributed to produce isodynamic lines 220A to 220C. The border 213 has a shape coinciding with the isodynamic stress line 220C of a bending stress induced on the base 212. The border 213 shown in Fig. 4 has an arcuate shape. An amount of setback, i.e., a distance D2 from the inner wall 202B of the cylinder 202 to the border 213 and a radius R2 of the arcuate shape are determined to prevent the suction reed 205 from contacting the opening end 202A of the cylinder 202 when the suction reed 205 is displaced by a maximum amount. A stopper 214 is provided in the opening end 202A of the cylinder 202.

The stopper 214 is a recess extending from the inner wall 202B in a direction T3 directing outward from the cylinder 202. When the suction reed 205 opens, the tongue 210 of the suction reed 205 contacts the stopper 214 to prevent the head 209 and the arm 211 from being distorted. An operation of the compressor 1002 will be described below.

The piston 203 reciprocates in the cylinder 202, and decreases the pressure in the cylinder 202 during a intake stroke. This creates a difference between a pressure in the suction port 207 and a pressure in the cylinder 202, accordingly applying a force to the head 209 of the suction reed 205. Then, the arm 211 of the suction reed 205 deflects inward and opens with respect to the base 212 as a fulcrum, thus opening the suction port 207 and introducing the refrigerant into the cylinder 202. During a discharge stroke, the pressure in the cylinder 202 increases to cause the suction reed 205 to close the suction port 207, thereby allowing the refrigerant to flow out from the discharge port 208 via a discharge valve to outside of the cylinder 202. When the suction reed 205 opens during a suction stroke, the tongue

210 contacts the stopper 214 to limit the deflection of the suction reed 205. This prevents the suction reed 205 from being distorted and reduces an internal stress produced in the suction reed 105.

The relation between a minimum width Wl of the arm 211, a width W2 of the base 212, a distance Ll from the position providing the minimum width Wl of the arm 211 to the base 212, the radius R2 of the arcuate shape of the border 213 at the gasket 206, and a stress produced at the border 213 was studied. It was confirmed that the border 213 had the shape, the arcuate shape according to Embodiment 2, approximating the isodynamic stress line 220C of a bending stress produced on the base 212 when the following relation is satisfied^:

0.45<20xLl/(R2x(W2-Wl))<1.80.

This relation prevents the suction reed 205 from breaking, and provides the compressor 1002 with high reliability. According to Embodiment 2, the minimum width Wl of the arm 211 is 8 mm, the width W2 of the base 212 is 12 mm, the distance Ll from the position providing the minimum width Wl of the arm 211 to the base 212 is 7 mm, and the radius R2 of the arcuate shape of the border 213 is 30 mm.

The compressor 1002 according to Embodiment 2 has an aperture 211A provided in the arm 211 of the suction reed 205. The aperture 211A allows the arm 211 to deflect by a large amount at the head 209. Accordingly, the opening area of the suction port 207 increases, accordingly introducing the refrigerant easily. The aperture 211A reduces the deflection of the arm 211 at the base 212. This reduces the stress produced on the base 212, accordingly providing the compressor 1002 with high refrigerating capacity, high efficiency, and high reliability. The setback amount, the distance D2 from the inner wall 202B of the cylinder 202 to the border 213 and the radius R2 of the arcuate shape are determined to prevent the suction reed 205 from contacting the opening end 202A of the cylinder 202 when the suction reed 205 deflects by a maximum amount. This structure prevents the suction reed 205 from contacting the opening end 202A of the cylinder 202, thus from deforming and breaking.

The border 213 has the arcuate shape coinciding with the isodynamic stress line of the bending stress produced on the base 212 of the suction reed 205, and hence, minimizes a space between the inner wall 202B of the cylinder 202 and the border 213 of the suction reed 205, which is provided by setting back the border 213 from the inner wall 202B in the direction directing towards the outside of the cylinder 202. Accordingly, the volume of the clearance is minimized, and prevents the refrigerating capacity of the compressor 1002 from decreasing due to the increase of the volume of the clearance. According to Embodiment 2, the suction port 207 has the non-circular shape to have a large opening area. A circular suction port having a large opening area increases a difference between a pressure in the cylinder 202 and a pressure in the port during a suction stroke, and provides the head 209 of the suction reed 205 with a large load, accordingly causing the suction reed 205 to deform and break. The suction port 207 having the non-circular shape reduces the deformation of the head 209 caused by a load applied to the head 209. The compressor 1002 has the suction port 207 having the large opening area and the suction reed 205 reducing the stress produced on the head 209, accordingly having high efficiency and high reliability.

According to Embodiment 2, the gasket 206 is made of strip of rubber material of mixture of fiber, binder, and rubber. The gasket may be made of paper coated with rubber material or paper with no coating of rubber material.

The size and shape of the border 213 of the suction reed 205, the shape of the suction port 207, the tongue 210 of the suction reed 205, and the stopper 214 of the cylinder 202 according to Embodiment 2 may be applicable to the compressor 1001 of Embodiment 1 shown in Figs. 1 and 2, providing the same effects.

The present invention is not limited to the foregoing embodiments.

INDUSTRIAL APPLICABILITY A compressor according to the present invention includes a suction reed hardly breaking, and has high reliability. This compressor is applicable to a refrigerating system, such as a refrigerator, an air conditioner, or a freezing refrigerator, and to a valve mechanism of a vacuum pump and an air compressor.

Claims

1. A compressor comprising: a cylinder having an opening end and an inner wall; a piston inserted in the cylinder and reciprocating along the inner wall of the cylinder; a valve plate for sealing the opening end of the cylinder, the valve plate having a suction port and a discharge port provided therein; a suction reed held between the opening end of the cylinder and the valve plate, the suction reed opening and closing the suction port; and a gasket provided between the opening end of the cylinder and the suction reed, wherein the suction reed includes a head for opening and closing the suction port; an arm elastically supporting the head, and a base connected to the arm, the base being held between the opening end of the cylinder and the valve plate, the base is held at a border positioned away from the inner wall of the cylinder in a direction towards outside of the cylinder, and the border has a shape coinciding with an isodynamic stress line of a bending stress produced on the base of the suction reed.

2. The compressor according to claim 1, wherein the border has an arcuate shape, and a minimum width Wl of the arm, a width W2 of the base, a distance Ll from a position providing the minimum width Wl of the arm to the base, and a radius R2 of the arcuate shape of the border satisfy the relation expressed as:

0.45<20xLlx(R2x(W2-Wl))<1.80.

3. The compressor according to claim 1, wherein the border has an arcuate shape, and a distance between the inner wall of the cylinder and the border and a radius of the arcuate shape of the border are determined to prevent the suction reed from contacting the opening end of the cylinder when the suction reed deflects.

4. The compressor according to claim 1, wherein the suction reed further includes a tongue projecting from the head, and the cylinder has a recess provided in the inner wall for contacting the tongue of the suction reed.

5. The compressor according to claim 1, wherein the valve plate further has a further suction port provided therein, the further suction port being opened and closed with the suction reed.

6. The compressor according to claim 1, wherein the suction port has a non-circular shape.

7. The compressor according to claim 1, wherein the arm has a width smaller than a width of the head.