JPH03242487A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To prevent an outflow of lubricating oil from a breathing hole by providing the gas breathing hole at the intermediate position of a communication hole at the center of a main shaft radial ly through space outside the main shaft, and further providing the lower end of the main shaft with a means for preventing the pressure rise of a fluid coming from a lower side. CONSTITUTION:An eccentric hole 3b is provided in the large bore part 3 of a main shaft 3, and a communication hole 3d is also provided between an eccentric oil feed hole 3c and the lower end of the eccentric hole 3b. A breathing hole 3e radially continuous to the space 22 of a casing is formed at the intermediate height of the communication hole 3d in the main shaft 3. A hole 31 continuous to the communication hole 3d is provided at the lower end of the main shaft 3, and a ball 32 so housed in the aforesaid hole 31 as to be vertically movable is fitted to the lower end of the main shaft 3. The ball 31 is retained with a cover 33, thereby constituting a fluid forced feed prevention means 30. When the hole 31 and communication hole 3d are filled with a fluid, the fluid in the breathing hole 3e is discharged to the space 23 with the rotation of the main shaft 3, and the ball 32 moves to the upper part of the hole 31, thereby closing the communication hole 3d.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll compressor used in an air compressor, a refrigerant compressor, etc., and particularly relates to an improvement in oil supply means using a main shaft.

[Conventional technology]

FIG. 3 is a longitudinal sectional view of a conventional scroll compressor. In the figure, reference numeral 1 denotes a closed container consisting of a lower container 1a and an upper container 1b, and a lubricating oil 25 is stored at the bottom. 3 is a main shaft with an eccentric hole 3b provided in the large diameter part 3a at the upper end, an eccentric oil supply hole 3C eccentric from the shaft center, and a communication hole 3d at the shaft center passing through the eccentric hole 3b and the lower end. is provided.

The main shaft 3 is provided with a gas vent hole 3e that communicates with the container interior space front portion 22 in the radial direction at an intermediate height position of the communication hole 3d.

Reference numeral 4 denotes a cylindrical body fixed to the lower end of the main shaft 3, the lower end of which is formed into a funnel shape, enters the lubricating oil 25, and the eccentric oil supply hole 3c constitutes a centrifugal pump means.

Reference numeral 5 designates a fixed scroll having a spiral protrusion 5b provided at 7 portions of a base plate portion 5a, and a discharge lower portion is provided in the center thereof. Reference numeral 6 designates an oscillating scroll in which a spiral protrusion 6b is provided on the upper part of a base plate part 6a, a oscillating shaft part 6C is provided in the lower part of the center part, and an oscillating IC is provided in the eccentric hole 3b of the main shaft 3. ] Hata Uke 1
3.

8 is a suction port formed on the outer circumferential side between both scrolls 5 and 6; 9 is a compression chamber formed into a shape e by both spiral protrusions 5b and i3b; 10 is an upper bracket for fixing the field scroll 5; The swinging scroll 5 is supported from below via an upper thrust bearing 14, and the large diameter portion 3a of the main shaft 3 is supported in the radial direction via an upper bearing 15. The upper bracket 10 is provided with an oil return hole 10a. 11
is a lower bracket fixed in the lower volume Wla, which fixedly supports the upper bracket 10, and supports the main shaft 3 from below and in the radial direction via the lower thrust bearing 16 and the lower bearing 17. The lower bracket 11 is provided with an oil return groove 11a on its side circumference, and a gas release hole Lot) is provided in the sleeve portion on the center side. 12 is an Oldham joint interposed between the upper bracket 10 and the oscillating scroll 6, which prevents the oscillating scroll 6 from rotating and guides its revolution; 18 is a driving electric motor with a rotor fixed to the main shaft 3; 19a and a stator 19b attached to the lower part of the lower platen 11 with bolts.

20 is a suction pipe hermetically secured to the lower container 14, and 21 is a discharge pipe hermetically secured to the upper container i1b.

Next, the operation of the above conventional scroll compressor will be explained.

When the main shaft 3 is rotated by the rotor 19a of the electric motor 18,
The oscillating scroll 2 performs a revolving oscillating motion with the intervention of the Oldham joint 12. As a result, both spiral protrusions 5b and 6b
The gas compression chamber 9 formed by the combination of the gas and gas moves toward the center, gradually reduces its volume, increases the gas pressure, and is sent from the discharge lower through the discharge pipe 21.

On the other hand, due to the centrifugal pump action due to the rotation of the main shaft 3 and the cylinder body 4,
The lubricating oil 25 rises through the eccentric oil supply hole 3C and fills each cavity 23.
Gas and liquid are separated by
e, and is discharged to the lower bracket 11 and the lower cavity 22.

[Problem to be solved by the invention]

In the conventional scroll compressor as mentioned above, when starting up,
If excessive foaming occurs in the lubricating oil 25, if the pressure in the cavity 23 becomes lower than the pressure in the cavity 22, or if the refrigerant liquid is incorporated in a refrigeration system, it may enter the closed container 1. However, if the person falls down to a position exceeding the height of the gas vent hole 3e,
In this state, the communication hole 3d and the gas vent hole 3θ are filled with lubricating oil 25 or refrigerant liquid, and as the main shaft 3 rotates, the fluid in the gas vent hole 3e is subjected to centrifugal force and is discharged into the cavity 22. be done. Since this centrifugal force is proportional to the fluid mass, the acting force is small when the communication hole 3d is filled with gas during normal operation, but becomes excessive when it is filled with liquid.

Therefore, the pressure inside the cylinder 4 and the communication hole 3d becomes lower than that in the cavity 22, that is, it becomes a negative pressure.
rises through the communication hole 3d and enters the cavity 22 from the gas vent hole 3e.
A bypass phenomenon occurs in which the inside is discharged upward, and the bearings 13 to
There was a problem that the amount of oil supplied to the lubricating oil 17 was insufficient, and the amount of stored lubricating oil 25 was temporarily insufficient, resulting in poor lubrication.0 This invention was made to solve these problems. We developed a scroll compressor that reliably discharges the gas in the lubricating oil from the gas vent hole in the main shaft, prevents the lubricating oil from flowing out from the gas vent hole that occurs transiently, and ensures good lubricating of the bearings. The purpose is to obtain.

[Means to solve the problem]

In the scroll compressor according to the present invention, at the axis of the main shaft,
A communication hole is provided that penetrates from the eccentric hole at the upper end to the lower end, and a gas vent hole is provided at an intermediate position of the communication hole, which communicates with the cavity outside the main shaft in the radial direction.

A liquid pressure feeding prevention means is provided at the lower end of the main shaft to prevent the pressure of liquid from increasing from below into the communication hole.

[Effect]

In this invention, when the lubricating oil tries to rise to the communication hole of the main shaft, it is blocked by the liquid pumping prevention means, and the lubricating oil is discharged from the communication hole to the lower cavity of the lower casing through the gas vent hole. is eliminated and good lubrication of the bearings is maintained.

〔Example〕

FIG. 1 is a vertical cross-sectional view of the rotating part of a scroll compressor according to an embodiment of the present invention, and is a vertical cross-sectional view of parts 3.3a to 3.3e.

4.6.6a to 60, 13, 23, and 19a are the same as the above conventional ones. As shown in the figure, liquid pumping prevention means 30 is provided at the lower end of the main a3.

This liquid pumping prevention means 30 is configured as follows. A hole 31 communicating with the communication hole 3d is provided at the lower end of the main shaft 3, and serves as a valve seat. 32 is a ball accommodated in the hole 31 so as to be movable up and down, and is attached to the lower end of the main shaft 3.
It is held by a lid 33. The ball 32 is made of, for example, polytetrafluoroethylene resin (PTFE), and has a specific gravity smaller than that of the lubricating oil 25.

The liquid pumping prevention means 30 configured in this manner is shown in an enlarged view in FIG. 2. The lid 33 is made of a disc and is provided with a plurality of small holes 33a, and is fixed by means such as mounting screws.

The weight of the ball 320 is set as follows. As mentioned above, the cylinder 4. The following factors can be cited as factors that cause the liquid level (lubricant oil level) in the communication hole 3d to become high.

(1) A simple increase in the amount of lubricating oil 25 stored. (2) Cylindrical body 4,
The pressure in the cavity in the communication hole 3d is lower than the pressure in the cavity 22 in the closed container 1.

For example, as shown in FIG.
, the volume of the ball 32 is Vb, and the weight is 01), then the weight of the hole 320 is set so that Gb≦io(Hg+Vb).

Moreover, if the pressure difference shown in the above factor (2) is known, if the pressure difference lP1 is the inner diameter of the communication hole 3d is d, then Gb≦πd' (
AP/4) + Vl)・ro Set the weight.

The structure of the scroll compressor according to an embodiment of the present invention is the same as that of the conventional scroll compressor described above except that a liquid pumping prevention means 30 is provided at the lower end of the main shaft 3, and the explanation thereof will be omitted.

Next, the operation will be explained as shown in FIG. FIG. 2(a) shows a case where gas is flowing through the hole 31 and the communication hole 3d,
FIG. 2(1)) shows a case where the liquid is about to rise.

Flows are indicated by dashed arrows and solid arrows, respectively.

First, during normal operation, gas generated from the lubricating oil 25 flows from the cylindrical body 4 to the small hole 33 of the lid 33.
a, and is discharged from the first hole 31 → the communication hole 3 d → the gas vent hole 3 e → the cavity 22.

At this time, the lifting force on the ball 32 due to the slight pressure difference accompanying the gas flow increases the weight of the ball 32, so
The ball 32 is descending and does not block the communication hole 3d. Therefore, when the hole 31 and the communication hole 3d are in a gas atmosphere, a good gas exhaust function can be obtained as in the conventional case.

Next, the hole 3 that occurs due to the factors (1) and (2) above.
1 and the communication hole 3d are filled with liquid, for example, when the liquid level reaches the gas vent hole 3e while the refrigerant is trapped in the airtight container 1 in a refrigeration system, the rotation of the main shaft 3 will be affected. Accordingly, the liquid in the gas vent hole 3e is caused by centrifugal force to flow into the cavity 23.
is discharged to. At this time, a negative pressure acts inside the communication hole 3a to suck the liquid inside the cylinder 4, but the ball 32 receives a lifting force due to this negative pressure and buoyancy, moves to the upper part of the hole 31, and moves to the top of the hole 31. ! Block L.

Therefore, the lubricating oil 25 is prevented from rising up the communication hole 3d and flowing out from the gas vent hole 3e, and the lubrication problem is solved.

In the above embodiment, the button is operated using a ball 32 as the liquid pressure feeding prevention means, but the same effect is not limited to this, and the same effect can be achieved by using a check valve means or the like.

〔Effect of the invention〕

As described above, according to the present invention, a means for preventing liquid pressure feeding is provided at the lower end of the main shaft with respect to the communication hole of the shaft center, so that lubricant oil is removed from the gas vent hole during transient conditions such as during startup. Outflow is prevented, stable oil supply to the bearings is possible, and a highly reliable scroll compressor can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the rotating part of a scroll compressor according to an embodiment of the present invention, FIG. FIG. 3 is an enlarged cross-sectional view of a conventional scroll compressor. 1... Airtight container, 3... Main shaft, 3a... Large diameter part, 3
b... Eccentric hole, 3C... Eccentric oil supply hole, 3d... Communication hole, 3e... Gas vent hole, 4... Cylindrical body, 5... Fixed scroll, 5a... Base plate part , 5b... spiral protrusion, 6... rocking scroll, 6a... base plate part, 6b...
... spiral protrusion, 6C... rocking shaft part, 7... discharge port,
9... Compression chamber, 13... Rocking bearing, 18... Electric motor, 25... Lubricating oil, 30... Liquid mole feeding prevention means,
3 parts: hole, 32: ball, 33: lid, the same reference numerals in the drawings indicate the same or equivalent parts.

Claims (1)

[Claims] A fixed scroll is provided with a spiral protrusion below the base plate, and a fixed scroll with a discharge port opened upward in the center, and a spiral protrusion is provided above the base plate, and a compression chamber is attached to the spiral protrusion between the two. An oscillating scroll is formed with a oscillating shaft provided below the base plate, and an eccentric hole is provided in the large diameter portion of the upper end to support the oscillating shaft through a bearing, and the oscillating scroll is oscillated by rotation. A main shaft for causing the scroll to oscillate, compressing the fluid in the compression chamber and discharging it from the discharge port, an electric motor arranged on the lower side of the main shaft to rotate and drive the scroll, and a bottom portion for accommodating the scroll part and the electric motor part. a closed container storing lubricating oil; and a cylindrical body connected to the lower end of the main shaft, the lower end of which extends into the lubricating oil to act as an oil pump, and penetrating the main shaft from an eccentric hole to the lower end; A scroll compressor that is provided with an eccentric oil supply hole located eccentrically from the shaft center, a communication hole located at the shaft center position, and a gas vent hole that communicates in the radial direction from an intermediate position of the communication hole to a hollow space outside the main shaft. The device is characterized in that it is provided with a liquid pumping prevention means disposed at the lower end of the main shaft to allow the gas in the cylindrical shape to freely flow to the communication hole and to prevent the liquid from flowing to the communication hole. scroll compressor.