Patent Application
20090145293
1. Field of the Invention
The present invention relates to a tilting plate type compressor for reciprocating pistons by a swinging rotation of a tilting plate (swash plate, wobble plate).
2. Description of Related Art
A conventional tilting plate type compressor is disclosed in Japanese Patent Application Laid-Open Number 2007-127084. As shown in
A drive shaft 103 is provided at the center of the housing 101. Bearing cavities 104 and 105 is formed near both ends of the drive shaft 103 within the front head 101b and the cylinder block 101a. The bearing cavity 105 in the cylinder block 101a is configured of an inside cavity 105a opening into an after-mentioned crank chamber 112, a center cavity 105b having a smaller inner diameter and an outside cavity 105c provided on the side of the valve plate 102 as shown in
Within the cylinder block 101a, cylinder bores 110 are formed on a circumference with the drive shaft 103 as the center. A piston 111 capable of reciprocating is provided in each of the cylinder bores 110. A crank chamber 112 is provided within the front head 101a, which communicates with the cylinder bores 110. Within the crank chamber 112, provided are a rotor 113 fixed on an outer circumferential surface of the drive shaft 103, a sleeve 114 provided slidably on the outer circumferential surface of the drive shaft 103, a journal 116 provided outside the sleeve 114 and linked with the rotor 113 via a link 115 and a tilting plate 117 fixed on an outer circumferential surface of the journal 116. The pistons 111 are coupled to an outer circumference of the tilting plate 117 via pairs of shoes 118.
First and second springs S1 and S2 are provided at both sides of the sleeve 114. The tilting plate 117 will be returned to its initial position due to a balance between elastic forces of the first and second springs S1 and S2 after a shutdown.
On the drive shaft 103 rotating, the pistons 111 are reciprocated within the cylinder bores 110, respectively, due to the rotor 113, the tilting plate 117 and so on. A reciprocating stroke amount of the pistons 111 is varied due to a tilted angle of the tilting plate 117.
A suction chamber 120 and a discharge chamber 121 are provided within the rear head 101c.
The valve plate 102 is interposed between the cylinder head 101a and the rear head 101c. Therefore, the cylinder bores 110 and the chambers 120 and 121 are partitioned by the valve plate 102.
In addition, an extraction path 122 communicating the crank chamber 112 with the suction chamber 120 and an intake path (not shown) communication the crank chamber 112 with the discharge chamber 121 are provided in the housing 101 and so on. The extraction path 122 includes the inside cavity 105a and an intra-axis path 123 provided in the drive shaft 13 as its path. The intra-axis path 123 is configured of a radial path 123a extending a radial direction of the drive shaft 103 and an axial path 123b extending an axial direction of the drive shaft 103 as shown in
According to the above-mentioned configuration, the tilting plate 117 swings to reciprocate the pistons 111 on the drive shaft 103 being rotated. Refrigerant is supplied into the cylinder bore 106 from the suction chamber 120 during a suction stroke of the piston 111. The supplied refrigerant is compressed and discharged into the discharge chamber 121 during a compression stroke of the piston 111. The discharged refrigerant is circulated in a refrigerating cycle to be served for air-conditioning or the like and returned to the tilting plate type compressor 100.
A pressure in the crank chamber 112 is made low when thermal load for the refrigerating cycle becomes large during the tilting plate type compressor 100 driving. As a result, a moment to increase a titled angle of the tilting plate 117 is applied to the tilting plate 117 and the journal 116 due to a pressure difference between a crank chamber pressure (a back pressure of the pistons 111) and a front pressure of the pistons 111. The link 115 swings in an arrowed direction a in
On the other hand, the pressure in the crank chamber 112 is made high when the thermal load for the refrigerating cycle becomes small. As a result, a moment to decrease the tilted angle of the tilting plate 117 is applied to the tilting plate 117 and the journal 116 due to the pressure difference between the crank chamber pressure (the back pressure of the pistons 111) the front pressure of the pistons 111. The link 115 swings in an arrowed direction b in
During the above-mentioned driving operation of the tilting plate type compressor 100, friction parts within the crank chamber 112 (the radial bearings 106 and 107, the sleeve 114, the tilting plate 117, the shoes 118 and so on) are lubricated by oil contained in the refrigerant supplied into the crank chamber 112. Therefore, oil is contained sufficiently in the refrigerant. The refrigerant sufficiently containing oil is discharged into the suction chamber 120 via the extraction path 122 for adjusting the pressure in the crank chamber 120. Specifically, the refrigerant flows from the chamber 120 into the bearing cavity 150 and then finally flows into the suction chamber 120 through the intra-axis path 123 as shown in
In addition, the oil in the refrigerant flowing into the radial path 123a of the intra-axis path 123 is scattered toward the bearing cavity 150 by a centrifugal force due to the rotation of the drive shaft 103. This oil scattering prevents the oil contained in the refrigerant from flowing out of the crank chamber 120.
However, the oil scattered due to the centrifugal force of the drive shaft 103 attaches onto an inner surface of the bearing cavity 150 and stays therearound. When a much amount of the oil has stayed there, the oil may rush into the intra-axis path 123. As a result, the oil may leak into the suction chamber 120 through the intra-axis path 123 finally.
In the above-mentioned example, an expanded recess 105d is provided on a circumferential surface of the bearing cavity 105 in order to supply the refrigerant into the bearing cavity 105 as much as possible. However, the expanded recess 105d enlarges a space capacity for the oil staying and flowing-out of the oil through the intra-axis path 123 cannot be prevented by the expanded recess 105d.
An object of the present invention is to provide a titling plate type compressor that can prevent oil from flowing-out from a crank chamber through an extraction path as much as possible.
An aspect of the present invention is to provide a capacity variable compressor that includes a housing within which a plurality of cylinder bores and a crank chamber communicating with the plurality of cylinder bores are provided; a drive shaft rotatably provided within the housing so as to penetrate the crank chamber and supported by the housing via a bearing provided within a bearing cavity; a tilting plate provided within the crank chamber and capable of swingably rotating due to a rotation of the drive shaft; a plurality of pistons capable of reciprocating within the plurality of cylinder bores, respectively, due to swingably rotating of the tilting plate; an extraction path communicating between the crank chamber and a suction chamber; and an intake path communicating between the crank chamber and a discharge chamber. The extraction path includes an intra-axis path provided within the drive shaft and opens into the bearing cavity. The intake path opens into the bearing cavity and communicates with the crank chamber via the bearing cavity.
According to the aspect of the present invention, on refrigerant to be extracted flowing into the intra-axis path, oil had attached on an inner surface of the intra-axis path is sprayed outward due to a centrifugal force of the drive shaft and then attached on an inner surface of the bearing cavity and so on. Since the attached oil is returned to the crank chamber due to the refrigerant flowing to be inhaled into the crank chamber, oil leakage from the crank chamber can be prevented as much as possible.
It is preferable that an expanded cavity communicating with the bearing cavity is provided around the bearing cavity, and the intra-axis path opens into the expanded cavity.
According to this, since oil is scattered toward not only the bearing cavity but also the expanded cavity due to the centrifugal force of the drive shaft, a space toward which oil is scattered can be increased. As a result, it can be prevented as much as possible that oil staying on the inner surface of the cavities rushes into the intra-axis path and leaks.
It is also preferable that the intake path opens into the bearing cavity (or the expanded cavity) at a farther position from the crank chamber than an opening position of the intra-axis path into the bearing cavity (or the expanded cavity).
According to this, since the refrigerant to be inhaled flows into the crank chamber through an area, onto which oil had been scattered due to the centrifugal force of the drive shaft and then on which the oil stays. As a result, returned oil amount to the crank chamber can be increased.
It is also preferable that the intake path opens at a lower position within the bearing cavity (or the expanded cavity) under an installed condition of the compressor.
According to this, oil had attached onto the inner surface of the bearing cavity (or the expanded cavity) may drop due to its weight and then stay at a lower area on the inner surface. Since the refrigerant to be inhaled flows into the crank chamber through the area where the oil stays, the returned oil amount to the crank chamber can be further increased.
Hereinafter, one embodiment according to the present invention will be explained with reference to drawings.
As shown in
A drive shaft 4 is provided at the center of the housing 2. One end of the drive shaft 4 is projected outward from the front head 2b and a pulley 7 is fixed on the projected end to receive engine rotation. The drive shaft 4 is configured to rotate by receiving a drive force from the pulley 7 fixed on its one end.
Bearing cavities 30 and 31 is formed near both ends of the drive shaft 4 within the front head 2b and the cylinder block 2a. The bearing cavity 31 in the cylinder block 2a is configured of an inside cavity 31a opening into an after-mentioned crank chamber 10, a center cavity 31b having a smaller inner diameter and an outside cavity 31c provided on the side of the valve plate 3 as shown in
Cylinder bores 8 are formed within the cylinder block 2a. The cylinder bores 8 are formed at even intervals on a circumference with the drive shaft 4 as the center. A piston 9 capable of reciprocating is provided in each of the cylinder bores 8.
The crank chamber 10 is provided within the front head 2b, which communicates with the cylinder bores 8. Within the crank chamber 10, provided are a rotor 11 fixed on an outer circumferential surface of the drive shaft 4, a sleeve 12 provided slidably on the outer circumferential surface of the drive shaft 4, a journal 13 provided outside the sleeve 12 and rotating along with the rotor 11, a tilting plate 15 fixed on an outer circumferential surface of the journal 13 and rear ends of the pistons 9, each coupled to an outer circumference of the tilting plate 15 via a pair of shoes 16.
An outer circumferential surface of the sleeve 12 is formed almost spherical to smoothly guide a transition of the tilted angle of the tilting plate 13. First and second springs S1 and S2 are provided at both sides of the sleeve 12. The tilting plate 15 will be returned to its initial position due to a balance between elastic forces of the first and second springs S1 and S2 after a shutdown. The journal 13 and the rotor 11 are linked by a guide pin 13a which is fixed on the journal 13 and inserted into a guide hole 11a of the rotor 11.
On the drive shaft 4 rotating, its rotation is transmitted to the tilting plate 15 by the rotor 11 and the journal 13 to reciprocate the pistons 9 within the cylinder bores 8. In addition, each stroke of the pistons 9 is varied due to the tilted angle of the tilting plate 15 to change a discharge amount of refrigerant. Mechanism for adjusting the tilted angle of the tilting plate 15 will be explained later.
A suction chamber 20 and a discharge chamber 21 for refrigerant gas are provided within the rear head 2c. The suction chamber 20 is connected to an outlet of an evaporator in a refrigerating cycle via a suction port (not shown). The discharge chamber 21 is connected to an inlet of a condenser in the refrigerating cycle via a discharge port (not shown). In addition, the cylinder bores 8 and the chambers 20 and 21 are partitioned by the valve plate 3. Discharge holes 24 are provided on the valve plate 3 within partitioning areas between the bores 8 and the discharge chamber 21. A discharge valve is provided at each of the discharge holes 22. Suction holes (not shown) are provided on the valve plate 3 within partitioning areas between the bores 8 and the suction chamber 20. A suction valve (not shown) is provided at each of the suction holes.
Further, an extraction path 25 is provided between the crank chamber 10 and the suction chamber 20, which is always opened. An intake path 26 is provided between the crank chamber 10 and the discharge chamber 21. A pressure control valve (not shown) is provided on the intake path 23. The pressure control valve 24 is configured to control a pressure within the crank chamber 10 by adjusting its valve opening.
As shown in
The intake path 26 is configured of the bearing cavity 31, a first refrigerant path 27, a hole (not shown) provided on the valve plate 3 and a second refrigerant path (not shown). The first refrigerant path 27 is provided in the cylinder block 2a and its one end opens into the bearing cavity 31. The second refrigerant path is provided in the rear head 2c. One end of the second refrigerant communicates with the hole and another end thereof opens into the discharge chamber 21. In addition, the one end of the first refrigerant path 27 opens into the inside cavity 31a at a farther position from the crank chamber 10 than the opening position of the intra-axis path 34. Furthermore, the one end of the first refrigerant path 27 opens at the lower position within the inside cavity 31a under an installed condition of the compressor 1.
In the above configuration, on the drive shaft 4 rotating, the tilting plate 15 rotates due to the rotational force of the drive shaft 4. Then, the pistons 9 reciprocate within the cylinder bores 8. During the suction stroke of the pistons 9 (stroke from TDC to BDC), the suction holes 23 are opened due to a pressure reduction within the cylinder bores 8. As a result, the refrigerant gas is supplied from the suction chamber 20 to cylinder bores 8.
During the compression stroke of the pistons 9 (stroke from BDC to TDC), the suction holes (not shown) are closed and the refrigerant gas within the cylinder bores 8 is compressed adiabatically by the pistons 9. The compressed refrigerant gas with high-temperature and high-pressure is discharged from the discharge holes 24 to the discharge chamber 21. The discharged refrigerant gas with high-temperature and high-pressure is discharged from the tilting plate type compressor 1 via the outlet port (not shown). The discharged refrigerant gas is circulated in the refrigerating cycle to be served for air-conditioning or the like and returned to the tilting plate type compressor 1 again.
A supplying amount of the refrigerant into the crank chamber 10 through the intake path 26 is reduced by way of the pressure control valve (not shown) to reduce a pressure in the crank chamber 10 when thermal load for the refrigerating cycle becomes large during the tilting plate type compressor 1 driving. As a result, a balance will be disrupted between a counter-clockwise moment (to move the tilting plate 15 in
On the other hand, the supplying amount of the refrigerant into the crank chamber 10 through the intake path 26 is increased by way of the pressure control valve (not shown) to increase a pressure in the crank chamber 10 when the thermal load for the refrigerating cycle becomes small. As a result, the balance will be disrupted between the counter-clockwise moment due to the crank chamber pressure (the back pressure of the pistons 9) and the elastic force of the first spring S1 and the clockwise moment due to the front pressure of the pistons 9 and the elastic force of the second spring S2. Thereby, the counter-clockwise moment becomes large to decrease the tilted angle of the tilting plate 15, so that the tilting plate 15 and the journal 13 swing in an arrowed direction b in
Explained will be the refrigerant flowing into or from the crank chamber 10 during the tilting plate type compressor 1 driving. The refrigerant flows into the suction chamber 20 with a lower pressure from the crank chamber 10 with a higher pressure through the extraction path 25. Specifically, the refrigerant to be extracted enters into the inside cavity 31a and then flows into the intra-axis path 34. On the refrigerant flowing into the intra-axis path 34, oil had attached on the inner surface of the intra-axis path 34 is sprayed outward due to a centrifugal force of the drive shaft 4 and then attached on the inner surface of the inside cavity 31a and so on. On the other hand, the refrigerant to be inhaled flows into the crank chamber 10 through the intake path 26. Specifically, the refrigerant to be inhaled flows into the inside cavity 31a through the first refrigerant path 27 of the intake path 26 and then enters into the crank chamber 10 via the inside cavity 31a. Therefore, the above-mentioned oil on the inner surface of the inside cavity 31a is returned to the crank chamber 10 due to the inhaled refrigerant flowing. As a result, oil leakage from the crank chamber 10 can be prevented.
In addition, the refrigerant to be extracted supplies oil to the radial bearing 6 and the thrust bearing 32 by way of passing through the bearing cavity 31 as mentioned above. Especially in the present embodiment, since the refrigerant to be extracted passing through the interior of the thrust bearing 32 and then flows into the intra-axis path 34, oil can be supplied to the thrust bearing 32 sufficiently.
In the present embodiment, the one end of the intake path 26 (the first refrigerant path 27) opens into the bearing cavity 31 (the inside cavity 31a) at a farther position from the crank chamber 10 than the opening position of the intra-axis path 34. Therefore, the refrigerant to be inhaled flows into the crank chamber 10 through an area, onto which oil had been scattered due to the centrifugal force of the drive shaft 4 and then on which the oil stays. As a result, returned oil amount to the crank chamber 10 can be increased.
In the present embodiment, the one end of the intake path 26 (the first refrigerant path 27) opens at the lower position within the bearing cavity 31 (the inside cavity 31a) under an installed condition of the compressor 1. Therefore, oil had attached onto the inner surface of the bearing cavity 31 may drop due to its weight and then stay at a lower area on the inner surface. Since the refrigerant to be inhaled flows into the crank chamber 10 through the area where the oil stays, the returned oil amount to the crank chamber 10 can be further increased.
A modified embodiment is shown in
The first refrigerant path 27 of the intake path 26 opens into the expanded cavity 40 at a farther position from the crank chamber 10 than an opening position of the intra-axis path 34.
In addition, one end of the first refrigerant path 27 opens at a lower position within the expanded cavity 40 under an installed condition of the compressor 1.
Other components in the present embodiment is the same as or similar to those in the above-mentioned embodiment. Therefore, the same or similar components are allocated with the identical numerals to omit redundant explanations.
Similarly in the present embodiment, oil had attached on the inner surface of the bearing cavity 31 is returned to the crank chamber 10 due to the inhaled refrigerant flowing into the bearing cavity 31 from the intake path 26. As a result, oil leakage from the crank chamber 10 can be prevented as much as possible.
In the embodiment, the expanded cavity 40 communicating with the inside cavity 31a is provided around the inside cavity 31a and the intra-axis path 34 opens into the expanded cavity 40. Therefore, since oil is scattered toward not only the bearing cavity 31 but also the expanded cavity 40 due to the centrifugal force of the drive shaft 4, a space toward which oil is scattered can be increased. As a result, it can be prevented as much as possible that oil staying on the inner surface rushes into the intra-axis path 34 and leaks.
In the present embodiment, the intake path 26 opens into the expanded cavity 40 at a farther position from the crank chamber 10 than the opening position of the intra-axis path 34. Therefore, the refrigerant to be inhaled into the expanded cavity 40 flows into the crank chamber 10 through an area, onto which oil had been scattered due to the centrifugal force of the drive shaft 4 and then on which the oil stays. As a result, returned oil amount to the crank chamber 10 can be increased.
In the present embodiment, the one end of the intake path 26 (the first refrigerant path 27) opens at the lower position within the expanded cavity 40 under an installed condition of the compressor 1. Therefore, oil had attached onto the inner surface of the bearing cavity 31 may drop due to its weight and then stay at a lower area on the inner surface. Since the refrigerant to be inhaled into the expanded cavity 40 flows into the crank chamber 10 through the area where the oil stays, the returned oil amount to the crank chamber 10 can be further increased.
Note that, in the above-mentioned modified embodiment, the refrigerant is extracted through the interior of the thrust bearing 32 to supply oil to the thrust bearing 32 sufficiently. However, oil may be extracted through the interior of the radial bearing 6 to supply oil to the radial bearing 6 sufficiently. Alternatively, oil may be extracted through both interiors of the trust bearing 32 and the radial bearing 6 to supply oil to the bearings 32 and 6 sufficiently.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-315992 | Dec 2007 | JP | national |
