Patent Application
20080008614
A description will be given below of an embodiment in accordance with the present invention with reference to the accompanying drawings.
A description will be given of a whole structure of an embodiment in accordance with the present invention with reference to
A compressor mechanism portion and an electric motor portion are stored in a sealed container 100, and an inner space of the sealed container is comparted into a space storing the compressor mechanism portion and a space to which a discharge pipe is installed, by an auxiliary frame 160 and a support plate 162 fixed to the sealed container and supporting the auxiliary frame.
As shown in
The communication path 213 may have a pipe and a communication pipe as shown in
As shown in
As shown in
A basic element of a driving portion driving so as to swing the orbiting scroll 120 is constituted by an electric motor stator 180 fixed to the sealed container, a rotor 181, the driving shaft 170, the Oldham ring 140 corresponding to a rotation preventing mechanism part of the orbiting scroll 120, a main bearing 131 and an auxiliary bearing 161 rotatably engaging the main frame 130 with the driving shaft 170 and constructing a shaft support portion of the driving shaft 170, an eccentric pin portion 172 of the orbiting scroll 120 and the driving shaft 170, and the bearing support portion 123 of the orbiting scroll engaging so as to be movable in a thrust direction and be rotatable. The main bearing 131 and the auxiliary bearing 161 of the driving shaft 170 are arranged on the compression chamber side of the electric motor and an opposite compression chamber side.
A trochoid pump 190 is provided at a shaft end portion of the driving shaft 170 on a discharge pipe installed chamber side, and an oil feeding pipe 191 constructing an oil feeding passage so as to be open to a lower portion of the sealed container is attached to the trochoid pump.
The driving shaft 170 is rotationally driven by the electric motor rotor 181, and the orbiting scroll 120 is swung on the basis of the rotation of the driving shaft, whereby the compressor chamber reduces a volumetric capacity and a compression operation is executed. The Oldham ring 140 is arranged in an outer peripheral space 153 of a space structured by the main frame 130 and the fixed scroll 110 together with the orbiting scroll 120, thereby preventing the orbiting scroll from rotating its own axis on the basis of a sliding motion of two sets of orthogonal keys (not shown) formed in the Oldham ring 140, and making it possible to compress the gas.
A working fluid is sucked into the compression chamber via a suction port 102 and a suction space 114 in accordance with the swinging motion of the orbiting scroll 120. The sucked working fluid is discharged from a discharge space 115 via the discharge port 113 in accordance with a compression stroke. The compressed gas passes through an upper passage 182 of an outer peripheral portion of the electric motor stator 180, a gap between the electric motor stator 180 and the electric motor rotor 181 and the like, via an outer peripheral gas passage 116 provided at a far position from a lubricating oil in an outer peripheral portion of the fixed scroll 110 and the main frame 130, cools the electric motor, passes through the upper communication path 211 and is discharged out of the compressor from the discharge pipe 101.
On the basis of the rotation of the driving shaft 170, the trochoid pump 190 is driven so as to take up a lubricating oil from the oil feeding pipe 191, supply the oil to the auxiliary bearing 161 via the oil feeding path 171 provided within the driving shaft and thereafter flow out from an auxiliary bearing end portion to a compressor mechanism portion chamber. The lubricating oil passing through the oil feeding path 171 lubricates an orbiting bearing 124 from a space in a drive shaft end portion, lubricates a main bearing 131 via a center portion space 152 sealed by a seal ring 150 and kept at a discharge pressure, is introduced to an oil discharge pipe 132 from an oil discharge hole provided in the frame and is discharged to a sealed container bottom portion at a far position from the outer peripheral gas passage 116. The seal ring 150 is received in a ring-like groove.
A part of the lubricating oil introduced to the center portion space 152 leaks out from the seal ring 150 so as to be introduced to the outer peripheral portion space 153, lubricates the Oldham ring 140 and the end plate surface forming an orbiting scroll end plate sliding portion and is introduced to the suction space 114 of the compressor chamber. Further, a part of the lubricating oil enters into the compressor chamber from a communication hole 126, is discharged together with a refrigerant gas, is separated within the sealed container, and is returned to a lubricating oil tank in a lower portion of the sealed container. A lot of lubricating oil discharged to the center portion space 152 is introduced to the oil discharge pipe 132 so as to be returned to the oil tank. As mentioned above, in accordance with the present embodiment, since an oil feeding system of the lubricating oil is separated from a compressed gas flow, it is possible to reduce a so-called oil ascent that the oil flows out of the compressor in accordance with the compressor gas flow.
The communication path 211 in the support plate 162 generates a pressure loss at a time of passing the refrigerant gas therethrough. On the basis of the pressure loss, a pressure in the space to which the discharge pipe is installed becomes somewhat lower than a pressure in the space containing the compressor mechanism portion. On the basis of the pressure difference, the lubricating oil in the compressor mechanism portion passes through the communication path 212 on a lower side of the support plate 162, and moves to the discharge pipe installed space, whereby it is possible to hold the lubricating oil in the discharge pipe installed space. The oil level difference is fluctuated in accordance with a cross sectional area of the communication path provided in the support plate and a flow rate of the refrigerant gas. The oil level difference H can be determined by the numerical expression (1).
H=(ζ/2g)·{N·G·(PS/Pd)1/n/ρA}2 (1)
In which, N is rotational speed, G is refrigerant circulating amount (per one rotation), ζ is resistance coefficient, g is gravitational acceleration, Ps is suction pressure, Pd is discharge pressure, ρ is suction gas density, A is communication hole area, and n is polytropic exponent.
The oil level difference can be determined by the numerical expression (1), however, is particularly fluctuated largely by a change of the rotational speed N in an inverter operation. If the oil level difference H necessary at a time of the low-speed operation is set, the oil level difference H is enlarged at a time of the high-speed operation, the oil level reaches the discharge pipe portion, and the lubricating oil flows out of the compressor.
On the contrary, if the oil surface difference H necessary at a time of the high-speed operation is set, the oil level difference H becomes small at a time of the low-speed operation, and it is impossible to hold a necessary amount of lubricating oil in the discharge pipe installed space.
In the present embodiment, the communication hole area is set in accordance with the numerical expression (1) in such a manner that the necessary oil surface difference H can be obtained at a time of the low-speed operation. In the case that the oil level ascends at a time of the high-speed operation, the communication path 213 is provided so as to be open to the position which is above the center of rotation of the electric motor rotor 170 and below the discharge port 101, and moves the lubricating oil to the compressor chamber side if the oil level reaches the upper portion than the opening end, whereby the lubricating oil does not flow out of the compressor from the discharge pipe.
A valve 214 which is normally open is attached to the opening portion on the compressor chamber side of the communication path 213. If the compressor is operated, and the pressure difference is generated in the vicinity of the support plate 162, the valve 214 is closed on the basis of the pressure difference. If the oil level of the discharge pipe installed chamber ascends and the communication path 213 is filled with the lubricating oil, a closing force of the valve 214 is lost, the valve 214 comes to the normal open state, and the lubricating oil is moved to the compressor mechanism portion chamber. If the oil level descends and the communication pipe is filled only with the gas pressure within the discharge pipe installed chamber, the valve 214 is closed. The oil level in the discharge pipe installed chamber is kept approximately at the end surface position of the opening portion of the communication path 213, by repeating the operations mentioned above.
As described in
The oil flowing out to the center portion space 152 flows out to the outer peripheral portion space 153 at a small amount in the seal portion of the seal ring 150 provided in such a manner as to come into contact with the end surface of the orbiting scroll shaft support portion 123, however, most oil passes through the rolling bearing 131 corresponding to the main bearing, and is returned to the lubricating oil reservoir 200 in the lower portion via a path 183 provided in a side surface of a bearing cap 133 and the oil discharge pipe 132. Accordingly, it is possible to reduce the so-called oil ascent that the oil is taken out of the compressor in accordance with the flow of the refrigerant gas of the working fluid, without mixing the oil lubricating the shat support portion 123 of the orbiting scroll member, and the main bearing 131 and the auxiliary bearing 161 of the drive shaft 170 with the working fluid sucked from the suction port 102.
In this case, the path 183 is structured such that the lubricating oil is introduced between the sealed container 100 and the electric motor stator 180, as exemplified in
The oil supply path 183 and the oil discharge pipe 132 provided in the center portion spaces 179 and 152, the rolling bearing 131 and the bearing cap 133 side surface are exposed to a pressure ascending effect caused by the pump effect and a pressure descending effect caused by the passage through the bearing portion and the gap portion, however, form a space having approximately same level as the discharge pressure. The outer peripheral portion space 153 is intermittently or continuously communicated with the compression chamber in process of compression via the communication hole 126, and comes to a pressure state between the suction pressure and the discharge pressure. According to a difference between the force pushing up the orbiting scroll, which force is generated by the pressure in the outer peripheral space 153 which is an intermediate pressure between the suction pressure and the discharge pressure and the pressure in the central spaces 179, 152 which is approximately the discharge pressure on the back surface side of the orbiting scroll lap, and the force pushing down the orbiting scroll which force is generated by the pressure produced on the compression chamber, the orbiting scroll is pushed in the direction of the fixed scroll 110, thereby, ensuring an airtightness of the compression chamber.
It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-187383 | Jul 2006 | JP | national |
