JPH0253639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric compressor having a scroll compressor, and more particularly to a mechanism for stably supplying oil to a compressor bearing.

A conventional scroll compressor is constructed as shown in FIG. That is, the orbiting scroll 1 consists of an end plate 2 and a lap 3, and the fixed scroll 4 has a lap 4a and is meshed with the lap 3. Reference numeral 5 denotes a swing bearing, which supports the crankshaft 7 together with a main bearing 6. Reference numeral 8 denotes an oil supply hole, which is provided to penetrate the crankshaft 7. Reference numeral 9 denotes a frame into which the main bearing 6 is fitted. 10
A motor is fixedly attached to the lower part of the closed container 11, and connects the crankshaft 7 and the rotor part. Reference numeral 12 denotes an oil reservoir, which is formed at the bottom of the closed container, and the tip of an oil supply device 23 provided at the shaft end of the crankshaft 7 is immersed in the oil in the oil reservoir 12. 13 is an inhalation pipe, which is connected to the airtight container 1
1 and communicates with the meshing suction chamber of the orbiting scroll 1 and the fixed scroll 4. 14
is a discharge hole, which opens into the upper space 2 inside the closed container 11. 15 is a passageway, and the airtight container 11 is
The inner upper space 21 and the inner space 22 of the closed container 11 between the frame 9 and the motor 10 are electrically connected. 1
Reference numeral 6 denotes a self-spindle prevention mechanism, which is interlocked between the orbiting scroll 1 and the frame 9. 17
is a back pressure hole, which is provided through the end plate 2 of the orbiting scroll 1, and is connected to the back pressure chamber 18 and the intermediate compression chamber 2.
Conducted with 0. 19 is a discharge pipe, and the above space 2
It is open to 2. 7a is a balance weight.

As described above, the above-described scroll compressor is provided with a back pressure chamber 18 on the back surface of the orbiting scroll 1, and in order to adjust this pressure, a back pressure hole 17 is provided to communicate the back pressure chamber 18 with the closed chamber 20 of the scroll during compression. The pressure in the back pressure chamber 18 is set between the suction pressure and the discharge pressure to prevent the orbiting scroll 1 from detaching, and oil is supplied to the orbiting bearing 5 and the main bearing 6 through the oil supply hole 8 in the crankshaft 7. Refueling. but,
In such a structure, when the cycle is operated when the balance pressure in the cycle is high, such as at startup, the pressure in the compression chamber of the back pressure hole 17 communicating with the back pressure chamber 18 becomes higher than the discharge pressure, and therefore the back pressure increases. Pressure chamber 1
This had the disadvantage that the pressure inside the bearing was higher than the discharge pressure and the bearing was no longer supplied with oil. For example, when the four-way valve is switched to a reverse cycle during defrosting during heating operation, the discharge pressure decreases, the suction pressure increases, and the pressure in the back pressure chamber 18 becomes higher than the discharge pressure. A similar phenomenon occurred and caused a practical problem.

The present invention was made in view of the above points, and an object of the present invention is to ensure that each bearing is reliably lubricated by ensuring that the pressure in the back pressure chamber is always lower than the discharge pressure. It is something to do.

In order to achieve the above object, the present invention provides a path that communicates the back pressure chamber with a pressure source lower than the discharge pressure, such as a suction pipe, in order to always maintain the pressure of the back pressure chamber lower than the discharge pressure. It is characterized by a configuration in which a regulating valve is provided and the passage is opened and closed by the pressure difference between the pressure in the back pressure chamber and the discharge pressure.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 2 and 3.

In the figure, the same or similar parts as in FIG. 1 are represented by the same reference numerals, and their explanations are omitted. A pressure regulating valve 24 is provided in the frame 9, one passage 25 of the pressure regulating valve communicates with the back pressure chamber 18, and the other passage 26 communicates with the space 22.
It is electrically conductive. Furthermore, the passage 27 is opened and connected to the suction pipe 13 via a communication pipe 28. A spring 29 is biased to press a piston 30, and the upper surface of the piston 30 is seated on a seat surface 31.

Due to the rotation of the motor 10, the orbiting scroll 1 performs an orbiting motion relative to the fixed scroll 4 by means of the crankshaft 7 and the rotation prevention mechanism 16. As a result, the volume of the space formed by the orbiting scroll 4 and the fixed scroll 1 decreases as it moves toward the center.
The gas sucked through the suction pipe 13 is compressed and discharged from the discharge hole 14 of the fixed scroll 4. The discharged gas flows into the space 22 through the passage 15, cools the motor 10, and is then discharged from the discharge pipe 19 to the outside of the compressor. On the other hand, the discharged oil accumulates in the oil reservoir 12 due to gravity. Further, the back pressure chamber 18 is communicated with the sealed chamber 20 during compression of the scroll through the back pressure hole 17, and the pressure inside the back pressure chamber 18 is lower than the discharge pressure. This pressure is a pressure balanced with the thrust force of the orbiting scroll 1. Therefore, since the oil in the oil reservoir 12 is at a high pressure, the swing bearing 5 and the main bearing 6 are supplied with oil by the pressure difference between the oil and the intermediate pressure lower than the discharge pressure. Oil is supplied through the oil supply hole 8 by the oil supply device 23. Oil entering the back pressure chamber 18 is sucked in through the back pressure hole 17 and discharged to the discharge side. The back pressure chamber 18 and the suction pipe 13 are connected by a communication pipe 28 via a control valve 24. It goes without saying that this communication pipe 28 may be connected to any pressure source lower than the discharge pressure, such as an accumulator (not shown) or a gas-liquid separator (not shown). The regulating valve 24 is made up of a piston 30 and a spring 29. Discharge pressure and back pressure are applied to both sides of the piston 30, respectively, and the piston 30 normally sits on a seat 31, but when the back pressure becomes higher than the discharge pressure, the piston 30 moves to the seat 31. The low pressure side communication hole 28 and the back pressure chamber 18 are connected to each other and gas flows to the low pressure side, lowering the pressure in the back pressure chamber 18 and stably lubricating the bearing. Note that the passage 25, which is the communication hole on the back pressure chamber side, is preferably connected to the back pressure hole 18.
According to this structure, when oil accumulates in the back pressure chamber 18, the oil is returned to the suction side, thereby reducing oil agitation loss due to the balance weight 7a.

According to the present invention, since the pressure in the back pressure hole can always be kept below the discharge pressure, it is possible to reliably supply oil to the swing bearing and the main bearing.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional scroll compressor, Fig. 2 is a sectional view of a scroll compressor of the present invention, and Fig. 3 is a sectional view of a conventional scroll compressor.
The figure is a structural diagram of a regulating valve. 1... Orbiting scroll, 2... End plate, 3... Wrap,
4...Fixed scroll, 5...Swivel bearing, 6...Main bearing, 7...Crankshaft, 7a...Balance weight,
8... Oil supply hole, 9... Frame, 10... Motor, 11
...Airtight container, 12...Oil sump, 13...Suction pipe, 14...
Discharge hole, 15... Passage, 16... Rotation prevention mechanism, 17
...Back pressure hole, 18...Back pressure chamber, 19...Discharge pipe, 24...
Pressure regulating valve, 25... passage, 26... passage, 27... passage, 28... communicating pipe, 29... spring, 30... piston, 3... seat surface.

Claims (1)

[Claims] 1. An orbiting scroll and a fixed scroll consisting of an end plate and a spiral wrap standing upright on the end plate, both scrolls are assembled with the wraps facing inward, and each lap and end plate are assembled with each other with the wraps facing inward. It has a scroll compression mechanism in which both scrolls move relative to each other so that the volume of the space formed by the scroll moves toward the center of the scroll. The inside of the closed container is communicated with the discharge port to maintain the pressure inside the closed container at the discharge pressure, while the back pressure chamber on the opposite side of the orbiting scroll is pressure-blocked from the inside of the closed container. During normal operation, the pressure in the back pressure chamber is lower than the discharge pressure, and the differential pressure is used to supply oil to the swing bearing and main bearing. An electric compressor characterized in that the electric compressor is connected to the compressor by a passage, and when the pressure in the back pressure chamber becomes higher than the discharge pressure, a control valve is opened to establish the communication. 2. The electric compressor according to claim 1, wherein the path opening into the back pressure chamber opens at the bottom of the back pressure chamber. 3. The electric compressor according to claim 1, wherein the control valve body is formed in the frame. 4. The electric compressor according to claim 1, wherein the path communicating with the suction side is a pipe, which penetrates the closed container and projects outside the closed container, and then opens to connect to the suction side pipe.