Patent Application
20130287618
The present invention relates to a refrigerant compressor to be used for a vehicle air-conditioning systems, and the like, and more specifically, relates to a recirculation structure for lubrication oils.
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 aft-conditioning system becomes high, heat exchange is prevented and the cooling performance drops. Accordingly, it is required to lower the oil circulation rate.
Therefore, as described in Patent Document 1, an oil recirculation mechanism is provided, which separates an oil from a refrigerant discharged from a compressing mechanism and returns the oil to a suction pressure region of the compressing mechanism.
The oil recirculation mechanism includes an oil-separation portion (separation chamber 41 and separation tube 43) for separating an oil from the refrigerant, an oil storage chamber (oil retaining chamber 44) for storing the separated oil, an oil return passage (oil supply passage 61a, 61b) through which the oil storage chamber communicates with a suction pressure region, and an orifice (fluid restrictor 62) that is a depressurizing device provided in the oil return passage.
Thus, in order to return the oil separated from the discharged refrigerant to the suction pressure region, in addition to the oil storage chamber and the oil return passage, it is necessary to provide an orifice as a depressurizing device in the oil return passage. Furthermore, in order to prevent clogging of such an orifice, it is necessary to provide a filter on the upstream side of the orifice.
Accordingly, it is necessary to add elements, that are an oil storage chamber, an oil return passage and a depressurizing device (orifice), to constitute an oil recirculation mechanism on a cylinder head side of a compressor housing, and further, it is necessary to add a filter. Since it is necessary to lay out these elements in the housing under various design restrictions, a process for forming and fabricating the housing becomes complicated, which has been causing deterioration of productivity.
Under these circumstances, it is an object of the present invention to provide a refrigerant compressor which has an oil recirculation mechanism excellent in productivity.
A refrigerant compressor according to the present invention premises a construction including a compressing mechanism that compresses a refrigerant gas drawn from an external refrigerant circuit and discharges the compressed refrigerant, and an oil recirculation mechanism that separates a lubrication oil from the refrigerant discharged from the compressing mechanism and returns the lubrication oil to a suction pressure region of the compressing mechanism.
Here, the oil recirculation mechanism includes: an oil separation portion for separating an oil from the discharged refrigerant; an oil storage chamber for storing the oil separated by the oil separation portion; an oil return passage through which the oil storage chamber communicates with the suction pressure region; and a depressurizing device provided in the oil return passage.
Furthermore, the oil storage chamber extends in a diametric direction of a compressor housing and has an open end at an outer face of the housing, the open end is occluded by an occluding member; a partition wall, that separates the oil storage chamber from the suction pressure region, is present in a region more inside than the opening of the open end; a through-hole, that is the oil return passage and that penetrates through the partition wall and has one end which opens to the oil storage chamber and the other end which opens to the suction pressure region, is linearly formed so that the through-hole can be observed from the opening of the open end; and the depressurizing device is accommodated and positioned in the through-hole.
According to the present invention, since the oil return passage and the depressurizing device are disposed in a region of the oil storage chamber more inside than the opening of the open end, it is possible to accommodate the oil recirculation mechanism compactly. Further, it is possible to easily form the oil return passage (through-hole) from the open end side of the oil storage chamber, and it is possible to easily attach the depressurizing device. Furthermore, since the attachment of the depressurizing device is easy, attachment of a depressurizing device with a filter also becomes easy.
Now embodiments of the present invention will be described in detail.
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 101a 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 102a 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 102a, 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 101a 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 117a is formed, and the outer peripheral portion of the swash plate 107 is accommodated in the recess 117a 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 101a.
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 on 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 103a through which the cylinder bores 101a (compression chambers of pistons 117) communicate with the suction chamber 119 in the cylinder head 104, and discharge ports 103b through which the cylinder bores 101a (compression chambers of pistons 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, as illustrated in
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 103c 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 will be described with reference to
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, an oil return passage through which the oil storage chamber communicates with a suction pressure region, and a depressurizing device provided in the oil return passage.
The discharge passage 104b is constituted by a lead-out hole 104b1 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 104b2 that has a cylindrical shape of which diameter is greater than that of the lead-out hole 104b1 and disposed substantially coaxially with the lead-out hole 104b1 and below the lead-out hole 104b1; an separation pipe 130 projecting into the separation chamber 104b2 and press-fit into and fixed to the lead-out hole 104b1; and an introduction hole 104b3 extending in a direction substantially perpendicular to the axial line of the separation chamber 104b2 and opening along an inner wall of the separation chamber 104b2, through which the separation chamber 104b2 communicates with the discharge chamber 120.
Accordingly, a gas-state refrigerant, that is discharged from each cylinder bore 101a into the discharge chamber 120 and contains an oil, flows through the introduction hole 104b3 into the separation chamber 104b2, 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 104b1 into the external refrigerant circuit. The introduction hole 104b3, the separation chamber 104b2 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 extends in the diametric direction of the cylinder head 104 and has an open end which opens downwardly at the outer face of the cylinder head 104, the oil storage chamber 132 is formed so that its opening area increases toward the open end, and the oil storage chamber 132 at the open end side has a cylindrical shape. The open end is occluded by the occluding member 134. The oil storage chamber 132 has a region bulging into the suction chamber 119 and the discharge chamber 120 so as to suppress increase of size of the compressor.
An open end of the separation chamber 104b2 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 104b2 drops directly into the oil storage chamber 132 and is stored. That is, the open end of the separation chamber 104b2 acts as a role of an oil introduction hole into the oil storage chamber 132.
In the oil storage chamber 132, a bulge portion 132a is provided so as to bulge into a region more inside than the opening of the open end, and the bulge portion 132a forms a partition wall separating the oil storage chamber 132 from the suction chamber 119. Further, through the bulge portion 132a forming the partition, a through-hole 132b being an oil return passage having one end which opens into the oil storage chamber 132 and the other end which opens into the suction chamber 119, is formed linearly so that the through-hole can be observed from the opening of the open end.
In the through-hole 132b, an orifice (orifice with a filter) functioning as a depressurizing device is accommodated and fixed.
The orifice 136 includes an orifice member 136a having a pipe shape and limiting a flow rate by its inner diameter, and a filter 136b made of a resin and covering an oil chamber side opening of the orifice member 136a. The filter 136b is constituted by a frame 136b1 having a tubular shape and a filter member 136b2 attached to the inner face of the frame 136b1. The filter 136b is disposed so as to protrude into the oil storage chamber 132 so that the tip of the filter 136b1 faces in proximity to the tip of the occluding member 134. That is, the occluding member 134 also functions of preventing the orifice 136 from coming out from the through-hole 132b.
Further, between the inner periphery of the through-hole 132b and the outer periphery of the orifice 136, an o-ring 138 being a sealing member is provided, and the orifice 136 is retained in the through-hole 132b by elasticity of the o-ring 138.
Here, the diameter of the orifice 136, that is the inner diameter of the pipe-shaped orifice member 136a, is set so that an oil is stored in the oil storage chamber 132.
Accordingly, an oil separated in the separation chamber 104b2 is stored in the oil storage chamber 132, and an oil stored in the oil storage chamber 132 is returned to the suction chamber 119 through the orifice 136 (orifice member 136a) by a pressure difference between the oil storage chamber 132 and the suction chamber 119.
The above oil recirculation mechanism provides the following effects.
Since the oil return passage (through-hole 132b) is linearly provided in a region of the oil storage chamber 132 more inside than the open end and the orifice with a filter is provided in the oil return passage (through-hole 132b), it is possible to accommodate the oil recirculation mechanism compactly.
Further, it is possible to easily form the oil return passage (through-hole 136b) and the oil introduction hole (separation chamber 104b2) from the open end side of the oil storage chamber 132, and it is possible to easily attach the orifice 136. Accordingly, such a construction is excellent in productivity.
Furthermore, the oil storage chamber 132 extends in the diametric direction of the cylinder head 104 and has an open end which opens downwardly at the outer face of the cylinder head 104, and the oil storage chamber 132 is formed so that its opening area increases toward the open end, the volume increases toward a lower region (occluding member 134 side) of the oil storage chamber 132. Thus, it is possible to obtain an oil-storing space effectively and to form the oil storage chamber 132 easily by casting.
Furthermore, in a cylinder head 104 in which the suction chamber 119 is disposed on an extended line of the axis of a drive shaft 106 and the discharge chamber 120 is disposed in an annular form so as to encircle the suction chamber 119 in the diametric direction, it is possible to easily dispose an oil introduction hole into the oil storage chamber 132 in an upper region of the cylinder head 104, and accordingly, it is possible to obtain a space for the oil storage chamber 132 in a lower region of the cylinder head 104 without significantly increasing the size of the compressor.
Furthermore, according to the embodiment of the present invention, between the inner periphery of the through-hole 132b and the outer periphery of the depressurizing device (orifice 136), a sealing member (o-ring 138) is provided, the depressurizing device (orifice 136) has a filter 136b covering an oil storage chamber side opening of the depressurizing device, and the filter 136b protrudes into the oil storage chamber so that the tip of the filter 136b faces in proximity to the tip of the occluding member 134. Accordingly, the occluding member 134 functions of preventing the filter 136b and the orifice 136 from coming out from the through-hole 132b, and it is not necessary to fix the depressurizing device (orifice 136) to the housing and thus attachment becomes easy. Further, since the depressurizing device (orifice 136) can be removed easily by removing the occluding member 134, such a construction is excellent in maintainability.
Furthermore, according to the embodiment of the present invention, the oil storage chamber 132 extends in the vertical direction so that the open end is on the lower side, and the oil introduction hole (open end of the separation chamber 104b2) into the oil storage chamber 132 is formed in a region opposing to the opening of the open end, and thus, it is possible to easily form the oil introduction hole from the open end side of the oil storage chamber 132.
Furthermore, according to the embodiment of the present invention, since the oil storage chamber 132 is formed so that its opening area increases toward the open end, the volume increases toward a lower region (occluding member 134 side) of the oil storage chamber 132 and it is possible to obtain an oil-storing space effectively and to form the oil storage chamber easily by casting.
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.
Furthermore, in the above embodiment, the oil storage chamber 132 extends in the vertical direction so that the open end is on the lower side, but the construction is not necessarily limited thereto, and the oil storage chamber 132 may be disposed so as to be inclined so that the open end is on the lower side.
Furthermore, in the above embodiment, a bulge portion is provided in the oil storage chamber and a through-hole is formed linearly through the bulge portion, but as illustrated in
In such a configuration, it is not necessary to form the oil storage chamber into a complex shape and it is possible to easily form the oil storage chamber.
Furthermore, in the above embodiment, a fixed orifice is employed as the depressurizing device, and, as the depressurizing device, a variable orifice or a valve of which opening degree is variable may be employed.
Furthermore, in the above embodiment, the suction chamber 119 is disposed on an extended line of the axis of a drive shaft 106 and the discharge chamber 120 is disposed in an annular form so as to encircle the suction chamber 119 in the diametric direction. In contrast to the abovementioned arrangement, the arrangement in which the discharge chamber 120 is disposed on an extended line of the axis of a drive shaft 106 and the suction chamber 119 is disposed in an annular form so as to encircle the discharge chamber 120 in the diametric direction, may be employed.
Furthermore, in the above embodiment, a reciprocation type variable displacement compressor is employed as the refrigerant compressor, and the refrigerant compressor may be a fixed displacement compressor. Furthermore, the compressor may be employs another compressing mechanism such as a scroll compressor or a vane compressor.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-287025 | Dec 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/076544 | 11/17/2011 | WO | 00 | 6/24/2013 |
