US20130272903A1

US20130272903A1 - Refrigerant Compressor

Info

Publication number: US20130272903A1
Application number: US13/997,543
Authority: US
Inventors: Tsutomu Ishikawa; Yujiro Morita; Yukihiko Taguchi
Original assignee: Sanden Corp
Current assignee: Sanden Corp
Priority date: 2010-12-24
Filing date: 2011-11-17
Publication date: 2013-10-17
Also published as: DE112011104509T5; CN103282661A; JP5413850B2; JP2012132407A; CN103282661B; WO2012086347A1; DE112011104509B4

Abstract

In a cylinder head 104 provided on a head side of a cylinder block 101 with a valve plate 103 interposed therebetween, a suction chamber 119 is formed on the center side and a discharge chamber 120 is formed so as to encircle the suction chamber 119. In the cylinder head 104, an oil storage chamber 132 for storing an oil separated from a discharged refrigerant by an oil separating portion (a separation pipe 130 etc.) is provided. The oil storage chamber 132 extends in the diametric direction of the cylinder head 104 integrally with the cylinder head 104 and has an open end at the outer face of the cylinder head 104, and the open end is occluded by an occluding member 134. Here, the oil storage chamber 132 has a portion bulging into the suction chamber 119.

Description

TECHNICAL FIELD

The present invention relates to a refrigerant compressor to be used for a vehicle air-conditioning system, and the like, and more specifically, relates to a cooling structure for lubrication oils.

BACKGROUND ART

In a refrigerant compressor, a lubrication oil is mixed in a refrigerant drawn into and discharged from the refrigerant compressor, but when an oil circulation rate (OCR) to an air-conditioning system becomes high, heat exchange is prevented and the cooling performance drops. Accordingly, it is required to lower the oil circulation rate.
Therefore, a circulation oil contained in a discharged refrigerant is separated and returned. However, since the oil separated from a high-temperature discharged refrigerant has a high temperature and thus has a low viscosity, lubrication performance becomes poor if such an oil is directly returned. Accordingly, it is required to cool the separated oil.
In a compressor described in Patent Document 1, to a cylinder head in which a suction chamber and a discharge chamber are formed, an auxiliary head is attached so as to extend in the axial direction of the cylinder head, and an oil storage chamber (chamber for retaining oil) is formed in the auxiliary head so that a separated oil is temporarily stored in the oil storage chamber. Further, the oil storage chamber is provided adjacently to the suction chamber, so that the oil in the oil storage chamber is cooled by a low-temperature drawn refrigerant.

CITATION LIST

Patent Document

Patent Document 1: Japanese Laid-Open Patent Application Publication No. S58-131380

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the refrigerant compressor described in Patent Document 1 has the following problems.
Since the discharge chamber is disposed in the central portion of a cylinder head and the suction chamber is disposed so as to encircle the discharge chamber, a region of the oil storage chamber adjacent to the suction chamber is narrow relative to an oil storage space of the oil storage chamber. Accordingly, when the oil storage amount becomes large, cooling of oil becomes insufficient.
Further, if the oil storage chamber is disposed adjacent to the suction chamber of the cylinder head, the cylinder head as a whole extends in the axial direction to increase the size of the compressor in the axial direction, such being not preferred.
Under these circumstances, it is an object of the present invention to provide a refrigerant compressor which achieves effective cooling of an oil in the oil storage chamber with a simple structure, and which can suppress increase of size of the refrigerant compressor in the axial direction.

Means for Solving the Problems

A refrigerant compressor according to the present invention premises a construction including a cylinder block that has a plurality of cylinder bores disposed in parallel to and around the axis of the cylinder block; a cylinder head that is provided on one end of the cylinder block with a valve plate interposed therebetween; pistons that are inserted from the other end of the cylinder block into the respective cylinder bores and configured to reciprocate in the cylinder bores to compress a refrigerant drawn from a suction chamber on the cylinder head side and discharge the compressed refrigerant into a discharge chamber on the cylinder head side; and an oil recirculation mechanism that separates a lubrication oil from the refrigerant discharged into the discharge chamber and returns the lubrication oil to a lubrication portion of the compressor.
Here, the cylinder head has, in its inside, the suction chamber, the discharge chamber, a suction passage for introducing a refrigerant drawn from an external refrigerant circuit into the suction chamber, and a discharge passage for leading out the refrigerant discharged into the discharge chamber to the external refrigerant circuit. The suction chamber is disposed on the center side in the diametric direction of the cylinder head, and the discharge chamber is disposed on the outer side in the diametric direction of the cylinder head so as to encircle the suction chamber.
Further, the oil recirculation mechanism has an oil storage chamber for storing the separated oil. The oil storage chamber includes a tubular portion, that extends in the diametric direction of the cylinder head integrally with the cylinder head and has an open end at the outer face of the cylinder head, and an occluding member that occludes the open end. The tubular portion has a bulge portion bulging to the suction chamber side.

EFFECTS OF THE INVENTION

According to the present invention, a high temperature oil in the oil storage chamber can be effectively cooled by a low temperature drawn refrigerant in the presence of the bulge portion into the suction chamber side, and it is possible to suppress drop of viscosity of the oil. Moreover, since the suction chamber is disposed in the center side in the cylinder head, it is easy to dispose the oil storage chamber adjacent thereto and so as to bulge into the suction chamber.
Further, by making the oil storage chamber bulge into the suction chamber side and thereby shift the oil storage chamber toward the suction chamber side, it is possible to suppress increase of the size of the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a refrigerant compressor (in particular, a variable displacement compressor) illustrating an embodiment of the present invention.

FIG. 2 is a view of a cylinder head observed from its valve-plate-side end.

FIG. 3 is a cross-sectional view of an oil storage chamber (A-A cross-sectional view in FIG. 2).

FIG. 4 is a cross-sectional view of a separation chamber.

FIG. 5 is a substantial-part cross-sectional view of a refrigerant compressor illustrating another embodiment of the present invention.

MODES FOR CARRYING OUT THE INVENTION

Now embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view of a refrigerant compressor (in particular, a variable displacement compressor) illustrating an embodiment of the present invention. Further, FIG. 2 is a view of a cylinder head observed from its valve-plate-side end, FIG. 3 is a cross-sectional view of an oil storage chamber (A-A cross-sectional view in FIG. 2), and FIG. 4 is a cross-sectional view of a separation chamber.
First, the basic construction of a variable displacement compressor will be described.
A variable displacement compressor 100 includes a cylinder block 101 that has a plurality of cylinder bores 101 a disposed in parallel to and around the axis of the cylinder block 101; a front housing 102 that is provided on one end of the cylinder block 101; and a cylinder head (rear housing) 104 that is provided on the other end of the cylinder block 101 with a valve plate (valve-port-formed member) 103 interposed therebetween. These components as well as interposed gaskets, which are not illustrated, are fastened together by bolts 140 to constitute a compressor housing.
In the central portions of the cylinder block 101 and the front housing 102, a drive shaft 106 is provided so as to extend laterally across a crank chamber 105 formed between the cylinder block 101 and the front housing 102, and a swash plate 107 is disposed around the drive shaft 106. The swash plate 107 is coupled via a connecting unit 109 with a rotor 108 fixed to the drive shaft 106, so that the inclination angle of the swash plate 107 along the drive shaft 106 is variable. Here, between the rotor 108 and the swash plate 107, a coil spring 110 for urging a force to the swash plate 107 toward the minimum inclination angle is attached, and further, on the other side across the swash plate 107, a coil spring 111 for urging a force to the swash plate 107 toward a direction of increasing the inclination angle is attached.
One end of the drive shaft 106 extends through a boss portion 102 a protruding outwardly from the front housing 102, to the outside and is connected to an electromagnetic clutch, which is not illustrated. Here, between the drive shaft 106 and the boss portion 102 a, a shaft seal device 112 is inserted so as to form a sealing between the inside and the outside of the front housing 102. The drive shaft 106 is supported by bearings 113, 114, 115 and 116 in radial and thrust directions, so that a drive force from an external drive source is propagated via the electromagnetic clutch to rotate the shaft 106.
In each cylinder bore 101 a of the cylinder block 101, a single head type piston 117 is inserted and disposed so that its head is on the cylinder head 104 side and that the piston 117 is reciprocatable. On the other end portion of the piston 117 opposite to the piston head, a rectangular recess 117 a is formed, and the outer peripheral portion of the swash plate 107 is accommodated in the recess 117 a so that the piston 117 and the swash plate 107 are configured to interlock with each other via a pair of front and rear shoes 118. Accordingly, by rotation of the drive shaft 106, each piston 117 can be reciprocated in each cylinder bore 101 a.
Inside of the cylinder head 104 is compartmented to form a suction chamber 119 and a discharge chamber 120. The suction chamber 119 is disposed in the center side in the diametric direction of the cylinder head 104 (on the extended axial line of the drive shaft 106), and the discharge chamber 120 is disposed on the outer side in the diametric direction of the cylinder head 104 so as to be in an annular form encircling the suction chamber 119.
In the valve plate 103, suction ports 103 a through which the cylinder bores 101 a (compression chambers of the piston 117) communicate with the suction chamber 119 in the cylinder head 104, and discharge ports 103 b through which the cylinder bores 101 a (compression chambers of the piston 117) communicate with the discharge chamber 120 in the cylinder head 104, are formed. In each suction port and each discharge port, a one-way valve (not illustrated) is provided.
In the cylinder head 104, a suction passage 104 a for introducing a refrigerant drawn from an external refrigerant circuit into the suction chamber 119, and a discharge passage 104 b for leading out a refrigerant discharged into the discharge chamber 120 to the external refrigerant circuit, are provided. Accordingly, the suction chamber 119 is connected to an air-conditioning system side via the suction passage 104 a and the discharge chamber 120 is connected to the air-conditioning system side via the discharge passage 104 b.
In this variable displacement compressor 100, rotation of the drive shaft 106 is converted by the swash plate 107 being a conversion mechanism into reciprocal movement of each piston 117, to draw and discharge the refrigerant. Here, the displacement can be changed by changing the stroke of each piston 117 by adjusting the inclination angle of the swash plate 107, and the inclination angle of the swash plate 107 is changed by the pressure in the crank chamber 105.
That is, since the inclination angle of the swash plate 107 is changed by a moment caused by pressure differences between front and back sides of all pistons 117, it is possible to optionally control the inclination angle of the swash plate 107 by the pressure in the crank chamber 105.
In order to achieve this control, a displacement control valve 200 is provided in the cylinder head 104. The displacement control valve 200 changes the opening degree of a gas supply passage 121 through which the discharge chamber 120 communicates with the crank chamber 105, to adjust an introduction amount of a discharge gas into the crank chamber 105.
Further, a refrigerant in the crank chamber 105 flows into the suction chamber 119 via a gas-extraction passage that passes through gaps between the drive shaft 106 and the bearings 115 and 116, a space 122 and an orifice 103 c formed in the valve plate 103.
Accordingly, by adjusting the opening degree of the displacement control valve 200, it is possible to change the pressure in the crank chamber 105 to change the inclination angle of the swash plate 107, and thereby to change the displacement. Here, the pressure in the suction chamber 119 is introduced into the displacement control valve 200 via a communication passage 123, and the displacement control valve 200 adjusts the introduction amount of the discharge gas into the crank chamber 105 so that the suction chamber 119 maintains a predetermined pressure.
Next, an oil recirculation mechanism for separating a lubrication oil from a discharged refrigerant and for returning the separated lubrication oil to a lubrication portion of the compressor will be described.
The oil recirculation mechanism includes an oil-separation portion for separating an oil from the discharged refrigerant, an oil storage chamber for storing the separated oil and an oil return passage for returning the oil from the oil storage chamber to a suction side (low pressure region).
The discharge passage 104 b is constituted by a lead out hole 104 b 1 that is an upward hole provided in an upper region of the cylinder head 104 and connected to an external refrigerant circuit; a separation chamber 104 b 2 that has a cylindrical shape of which diameter is greater than that of the lead out hole 104 b 1 and disposed below the lead out hole 104 b 1; a separation pipe 130 projecting into the separation chamber 104 b 2 and press-fit into and fixed to the lead out hole 104 b 1; and an introduction hole 104 b 3 extending in a direction substantially perpendicular to the axial line of the separation chamber 104 b 2 and opening along an inner wall of the separation chamber 104 b 2, through which the separation chamber 104 b 2 communicates with the discharge chamber 120.
Accordingly, a gas-state refrigerant, that is discharged from each cylinder bore 101 a into the discharge chamber 120 and contains an oil, flows through the introduction hole 104 b 3 into the separation chamber 104 b 2, and while the refrigerant whirls around the separation pipe 130, an oil is separated and a gas-state refrigerant is discharged through the inside of the separation pipe 130 and the lead out hole 104 b 1 into the external refrigerant circuit. The introduction hole 104 b 3, the separation chamber 104 b 2 and the separation pipe 130 constitute an oil separation portion for separating an oil from the discharged refrigerant.
In order to store the oil separated by the oil separation portion, an oil storage chamber 132 is provided.
The oil storage chamber 132 includes a tubular portion that extends in the diametric direction of the cylinder head 104 integrally with the cylinder head 104 and has an open end at the outer face of the cylinder head 104, and an occluding member 134 that occludes the open end. In more detail, the oil storage chamber (tubular portion) 132 has a substantially cylindrical shape extending in the diametric direction of the cylinder head 104 so as to extend through the center of the suction chamber 119 and obliquely across the suction chamber 119. The oil storage chamber 132 has an open end opening downwardly at the outer face of the cylinder head 104, and the open end is occluded by the occluding member 134. The oil storage chamber 132 is formed so that its cross-sectional area increases toward the open end so that its oil storage space increases toward its lower region.
The oil storage chamber 132 has a bulge portion 132 a bulging into the suction chamber 119 for cooling a stored oil.
Since the oil storage chamber 132 is disposed obliquely across the suction chamber 119 so as to cross the center of the suction chamber, that is so as to cross an imaginarily extended line of an axial center of the drive shaft 106, when the cylinder head 104 is observed from the direction of FIG. 2, most of the region from the lower region to the upper region bulges into the suction chamber 119. Further, FIG. 3 illustrates a cross section (A-A cross section of FIG. 2) of the oil storage chamber 132, which shows that an axial center of the oil storage chamber 132 formed into a substantially cylindrical shape bulges into the suction chamber 119 so that at least a half a circumferential wall of the oil storage chamber 132 faces the suction chamber 119.
Accordingly, a high temperature oil stored in the oil storage chamber 132 is effectively cooled by a low temperature refrigerant in the suction chamber 119.
Here, by making the oil storage chamber 132 bulge into the cylinder head 104, it is possible to suppress increase of size of the variable displacement compressor 100 caused by provision of the oil storage chamber 132, and by forming the oil storage chamber 132 into a tubular form, it is possible to limit a size-increase region.
An open end of the separation chamber 104 b 2 opens directly into a region of the oil storage chamber 132 opposing to the occluding member 134, and an oil separated in the separation chamber 104 b 2 drops directly into the oil storage chamber 132 and is stored. That is, the open end of the separation chamber 104 b 2 acts as an oil introduction hole into the oil storage chamber 132.
Meanwhile, in order that the oil separated and stored in the oil storage chamber 132 is returned to the suction side, a lower region of the oil storage chamber 132 communicates with the suction chamber 119 via an orifice 136 that functions as an oil-returning passage and a depressurizing means.
Accordingly, the high temperature oil separated in the separation chamber 104 b 2 is stored in the oil storage chamber 132, cooled by the low temperature refrigerant in the suction chamber 119 through the bulge portion 132 a, and returned to the suction chamber 119 via the orifice 136 by a pressure difference between the oil storage chamber 132 and the suction chamber 119. The returned oil is drawn into the cylinder bores 101 a and lubricates the inside of the variable displacement compressor 100.
Here, as illustrated in FIGS. 2 and 3, the suction passage 104 a extends in the diametric direction of the cylinder head 104 and is provided so that an imaginary line obtained by extending the suction passage 104 a into the suction chamber 119 crosses the bulge portion 132 a. Accordingly, a main flow of the refrigerant flowing through the suction passage 104 a into the suction chamber 119 directly collides with the bulge portion 132 a, and the oil stored in the oil storage chamber 132 is cooled further effectively.
According to this embodiment, the oil storage chamber 132 is constituted by a tubular portion, that extends in the diametric direction of the cylinder head 104 integrally with the cylinder head and has an open end at the outer face of the cylinder head, and an occluding member 134 that occludes the open end. The tubular portion has a bulge portion 132 a bulging into the suction chamber 119. Accordingly, a high temperature oil in the oil storage chamber 132 is effectively cooled by the low temperature drawn refrigerant, and it is possible to suppress drop of viscosity of the oil and to suppress increase of the size of the compressor.
Further, according to this embodiment, since the bulge portion 132 a includes at least a lower region of the oil storage chamber 132, it is possible to cool an oil returned to the suction side (low pressure region) regardless of the amount of the oil.
Further, according to this embodiment, since the oil storage chamber 132, that is, its tubular portion, is formed so that its cross-sectional area increases toward the open end that opens downwardly, even when the amount of the stored oil is small, the oil is always stored. Further, by increasing the space of the lower region bulging to the suction chamber 119 side, it is possible to securely cool an oil to be returned to the suction side.
Further, according to this embodiment, since the oil storage chamber 132 is provided so that the bulge portion 132 a crosses an axial line of the cylinder head 104 (extended axial line of the drive shaft 106), the oil storage chamber 132 is provided so that the bulge portion 132 a passes through the vicinity of the center of the suction chamber 119, and accordingly, the region bulging into the suction chamber 119 increases to increase the cooling effect.
Further, according to this embodiment, since the oil storage chamber 132 is provided laterally across the suction chamber 119, it is possible to further increase the cooling area and to cool the high temperature oil further effectively.
Further, according to this embodiment, since the suction passage 104 a is disposed so that an imaginary line obtained by extending the suction passage 104 a into the suction chamber 119 crosses the bulge portion 132 a, heat exchange is promoted and the oil is cooled effectively.
Here, when the lubrication oil is cooled by the drawn refrigerant, the temperature of the drawn refrigerant rises. However, since the amount of lubrication oil to be cooled is limited, the temperature rise of the drawn refrigerant is small, and the above advantage is by far greater than a disadvantage due to the temperature rise.
Next, another embodiment of the present invention will be described with reference to FIG. 5.
FIG. 5 is a substantial-part cross-sectional view of a refrigerant compressor illustrating another embodiment of the present invention. Here, elements common to those of FIG. 1 are indicated by the same symbols and their explanations are omitted. Explanation will be made for different elements.
An oil storage chamber 132 having a cylindrical shape is constituted by a lower region having a large diameter and an upper region having a small diameter, a bulge portion 132 a is constituted by the lower region 132 a 1 and the upper region 132 a 2, and the bulge portion 132 a 2 of the upper region is smaller than the bulge portion 132 a 1 of the lower region in bulge volume.
By this configuration, an oil stored in the lower region, that is to be returned to the suction chamber 119, is effectively cooled. Further, since the upper region is smaller than the lower region in bulge volume, heat exchange through the bulge portion 32 a 2 of the upper region with the sucked refrigerant is suppressed, and it is possible to suppress unnecessary heating of the drawn refrigerant.
Here, the oil storage chamber 132 may be formed into a taper form from the separation chamber 104 b 2 side toward the lower region and the bulge volume may be adjusted. Further, the oil storage chamber 132 may be disposed so as to be sloped and the bulge volume may be adjusted. Further, the upper region of the oil storage chamber not necessarily bulges.
According to this embodiment, the bulge volume of the oil storage chamber 132 increases toward the lower region and an oil stored in the lower region, that is to be returned to the suction chamber 119, is effectively cooled. Further, the upper region of the oil storage chamber 132 does not bulge into the suction chamber 119 or the upper region is smaller than the lower region in the bulge volume. Accordingly, heat exchange through the bulge portion of the upper region with the drawn refrigerant is suppressed, and it is possible to suppress unnecessary heating of the drawn refrigerant.
Here, the embodiments illustrated in the drawings are only examples of the present invention, and it is a matter of course that the present invention includes not only the constructions directly illustrated in the above embodiments, but also various improvements and modifications within the scope of claims usually done by a person skilled in the art.
For example, the oil separation portion is of a centrifugal separation type employing a separation pipe 130 in the above embodiments, but the separation pipe 130 is not necessarily employed. Further, the oil separation portion may be of another separation type such as a collision separation type, or a region in the discharge chamber 120 in which an oil tends to be accumulated may communicate with the oil separation chamber 132.
Further, in the above embodiments, the oil separation chamber 132 is disposed so as to be sloped so that the open end is on the lower side, but the structure is not necessarily limited thereto and for example, the open end may be on the horizontally lateral side.
Further, in the above embodiments, the oil separation chamber 132 is constituted by a tubular portion having a cylindrical shape, but the tubular portion may have a prismatic tubular shape such as a substantially quadrangular tubular shape.
Further, the suction passage 104 a may have a bulge portion bulging into the suction chamber 119, and in this configuration, an oil is more effectively cooled by drawn refrigerant flow.
Further, in the above embodiments, as the oil return passage, a structure in which the oil storage chamber 132 communicates with the suction chamber 119 via the orifice 136 is employed, but a valve may be disposed instead of the orifice, or the oil storage chamber 132 may communicate with the crank chamber 105.
Further, in the above embodiments, a variable displacement compressor is employed as the refrigerant compressor, but it may be a fixed displacement compressor. Further, the compressor may be a clutchless compressor having no electromagnetic clutch, or a compressor driven by a motor.

REFERENCE SYMBOLS

100 variable displacement compressor
101 cylinder block
101 a cylinder bore
102 front housing
102 a boss portion
103 valve plate
103 a suction port
103 b discharge port
103 c orifice
104 cylinder head
104 a suction passage
104 b discharge passage
104 b 1 lead out hole
104 b 2 separation chamber
104 b 3 introduction hole
105 crank chamber
106 drive shaft
107 swash plate
108 rotor
109 connecting unit
110, 111 coil spring
112 shaft seal device
113, 114, 115, 116 bearing
117 piston
117 a recess
118 shoe
119 suction chamber
120 discharge chamber
121 gas supply passage
122 space
123 communication passage
130 separation pipe
132 oil storage chamber
132 a bulge portion
134 occluding member
136 orifice
140 fastening bolt
200 displacement control valve

Claims

1. A refrigerant compressor comprising:

a cylinder block that has a plurality of cylinder bores disposed in parallel to and around the axis of the cylinder block;

a cylinder head that is provided on one end of the cylinder block with a valve plate interposed therebetween;

pistons that are inserted from the other end of the cylinder block into the respective cylinder bores and configured to reciprocate in the cylinder bores to compress a refrigerant drawn from a suction chamber on the cylinder head side and discharge the compressed refrigerant into a discharge chamber on the cylinder head side; and

an oil recirculation mechanism that separates a lubrication oil from the refrigerant discharged into the discharge chamber and returns the lubrication oil to a lubrication portion of the compressor,

wherein the cylinder head has, in its inside, the suction chamber, the discharge chamber, a suction passage for introducing a refrigerant drawn from an external refrigerant circuit into the suction chamber, and a discharge passage for leading out the refrigerant discharged into the discharge chamber to the external refrigerant circuit,

wherein the suction chamber is disposed on the center side in the diametric direction of the cylinder head,

wherein the discharge chamber is disposed on the outer side in the diametric direction of the cylinder head so as to encircle the suction chamber,

wherein the oil recirculation mechanism has an oil storage chamber for storing the separated oil,

wherein the oil storage chamber includes a tubular portion, that extends in the diametric direction of the cylinder head integrally with the cylinder head and has an open end at the outer face of the cylinder head, and an occluding member that occludes the open end, and

wherein the tubular portion has a bulge portion bulging to the suction chamber side.

2. The refrigerant compressor according to claim 1, wherein the bulge portion includes at least a lower region of the oil storage chamber.

3. The refrigerant compressor according to claim 2, wherein the oil storage chamber is disposed so that the bulge portion crosses the axis of the cylinder head.

4. The refrigerant compressor according to claim 3, wherein the oil storage chamber is disposed so as to cross the suction chamber.

5. The refrigerant compressor according to claim 1, wherein the suction passage is disposed so that an imaginary line obtained by extending the suction passage into the suction chamber crosses the bulge portion.

6. The refrigerant compressor according to claim 2, wherein an upper region of the oil storage chamber does not bulge into the suction chamber side or is smaller than the lower region in bulge volume.