JPH0144915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an open gas compressor used for automobile air conditioning compressors, etc., and particularly relates to improving the sealing performance and durability of the shaft sealing device thereof. .

Conventional configurations and their problems Regarding open refrigerant compressors with differential pressure oil supply conventionally used in compressors for automobile air conditioning, etc., for example, Japanese Patent Application Laid-Open No. 133811/1982 and Japanese Patent Application Laid-Open No. 1983-1989
Various proposals have been made in Publication No. 78190, Japanese Utility Model Application Publication No. 109686/1986, and so on. However, including this proposal, oil is supplied to each sliding part using the differential pressure between the high pressure side and the low pressure side within the compressor body, as shown in the conventional method shown in FIG. In a so-called differential pressure oil supply type rolling piston rotary compressor, sufficient consideration has not been given to ensuring an oil film on the airtight sliding surface of the shaft sealing device. That is, the oil reservoir 14 on the high pressure side and the shaft sealing device space 26 on the low pressure side are communicated through the oil suction passage 11, the gap between the thrust bearing 5, and the gap between the needle bearings 4 and 4a, and further, the shaft sealing device space 26 and the suction refrigerant gas passage 27 through a bypass passage 28a.

In addition, in order to reduce the amount of refrigerating machine oil and refrigerant gas leaking from the shaft seal device 22, a pressure reducing device 15 (for example, an oil seal) is installed in the oil supply path between the oil reservoir 14 and the shaft seal device space 26. The shaft sealing device space 26 was devised to have a low pressure atmosphere by attaching it to the drive shaft 8b and the front plate 2a.

However, with just this type of fuel passage configuration,
This is because the discharge pressure does not reach the appropriate value during the first few minutes of compressor startup. The oil supply from the oil reservoir 14 reaches only the pressure reducing device 15, and the shaft seal device space 26 downstream of the pressure reducing device 15 is not supplied with oil. Also,
Conversely, if the pressure reduction capacity of the pressure reduction device 15 is reduced,
During normal operation, the oil supply to the shaft sealing device space 26 becomes excessive, the pressure in the shaft sealing device space 26 increases, and there is a problem that leakage of refrigerating machine oil and refrigerant gas increases. The most important problem is that the relationship between the pressure in the shaft sealing device space 26 and the amount of refrigerant leaking from the shaft sealing device 22 after the compressor is stopped is shown in Figure 2 (the horizontal axis is the elapsed time after the compressor is stopped, When the vertical axis shows atmospheric pressure and refrigerant leakage amount),
Due to the pressure balance of the refrigeration cycle, refrigerant gas flows into the shaft sealing device space 26 through the bypass passage 28a and becomes an intermediate pressure between high pressure and low pressure.After that, the refrigerant gas is cooled and the pressure gradually decreases. The refrigerating machine oil in the space 26 flows out to the suction refrigerant gas passage 27 via the bypass passage 28a, and as the residual oil decreases, the oil film formation on the sliding surface of the shaft sealing device 22 is gradually lost, and the amount of refrigerant leaked from the compressor decreases. The problem is that the amount of refrigerant leaks increases dramatically compared to when the refrigerant is in operation, and especially when vibrations are transmitted from the prime mover while the compressor is stopped, such as in compressors for automobile air conditioning, there is a disadvantage that the amount of refrigerant leaks further increases.

OBJECTS OF THE INVENTION The present invention is particularly intended to improve the sealing performance and durability of the shaft sealing device by eliminating the oil film breakage of the shaft sealing device when the compressor is stopped.

Structure of the Invention As a structure for this purpose, the present invention includes a shaft sealing device for ensuring airtightness of gas and lubricating oil in the compressor main body, and a pressure reducing device for supplying oil from an oil reservoir on the discharge side to the shaft sealing device space. a bypass passage communicating from the shaft sealing device space to the suction gas passage of the compressor main body; and a passage driven by a compression drive shaft upstream of the oil supply passage. A lubrication device is provided that performs intermittent lubrication only when the compressor body is rotating, and when the compressor main body is stopped, the rotation body blocks the lubrication passage by regulating the stop angle of the drive shaft, and the bypass passage is provided with the shaft sealing device. A check valve device is provided that communicates only in one direction from the space to the intake gas passage when the differential pressure is equal to or higher than a set pressure.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIGS. 3 and 4 showing one embodiment thereof.
The explanation will be given with reference to the figure and FIG.

This embodiment shows an open type rolling piston rotary refrigerant compressor, in which a front plate 2 and a rear plate 3 are arranged at both ends of a cylinder block 1, and a needle bearing 4 is provided on the up plate 3.
and a thrust bearing 5 mounted thereon, a thrust bearing holding plate 7 having a fixed passage 6 at its end, and a rotating body having a rotating passage 9 driven by a drive shaft 8 and communicating intermittently with the fixed passage 6. 10,
Oil case 12 having a narrow oil suction passage 11
is located. The bottom of the compressor is the discharge space 13
This is the oil sump 14 that leads to the Further, a pressure reducing device 15 consisting of a needle bearing 4a and a simple shaft sealing device (such as an oil seal) is attached to the front plate 2. Then, needle bearings 4, 4a and thrust bearing 5
A piston 17 rotating inside a cylinder 16 is loosely fitted into the eccentric portion 8a of the drive shaft 8 supported by the partition vane 18, which is pressed by a spring 19 so as to be in constant contact with the piston 17. There is. A discharge valve device (not shown) is attached to the rear plate 3, and a discharge cover 20 covers it. moreover,
An outer cylinder 21 is welded and fixed to the front plate 2 and surrounds the compression function component to form a discharge space 13. Further, a shaft sealing device 22 and a main body portion 24 of an electromagnetic clutch 23 are attached to the end of the front plate 2 on the power drive side, and an armature portion 25 of the electromagnetic clutch 23 is attached to the end of the drive shaft 8 on the power transmission side. It is being Shaft seal device space 26 of shaft seal device 22
and a suction refrigerant gas passage 27 adjacent to the cylinder 16.
is communicated with by a bypass passage 28. As shown in FIG. 5, the bypass passage 28 includes a throttle passage A.
29a is installed, and this valve body 30
A steel ball 31 is installed between the and the throttle passage B29b,
A check valve 33 is installed that allows sealing only when the valve seat A 32a and the steel ball 31 are in close contact with each other, but cannot achieve a tight seal between the valve seat B 32b and the steel ball 31. Furthermore, the fixed passage 6 and the opening/closing passage 9 are in communication with the oil reservoir 14 and the suction refrigerant gas passage 27 only at the rotation angle of the drive shaft 8 at which the partition vane 18 is at the most retracted position with respect to the cylinder side. They are communicated by an oil supply device 34 that passes through gaps between the bearings and sliding parts.

In such a configuration, after the electromagnetic clutch 23 is energized, the armature portion 25 is attracted to the main body portion 24, power is transmitted from the prime mover (not shown), the drive shaft 8 rotates, and the refrigerant gas begins to be compressed.
The pressure in the discharge space 13 increases and the suction refrigerant gas passage 2
The pressure at 7 decreases, creating a differential pressure between them. The refrigerating machine oil in the oil sump 14 is distributed between the oil suction passage 11, the fixed passage 6, the gap between the thrust bearing 5, the gap between the needle bearing 4, the gap between the inside of the piston 17 and the eccentric portion 8a of the drive shaft 8, and the gap between the needle bearing 4a. , shaft sealing device space 26, bypass passage 2
8 to the suction refrigerant gas passage 27 and the cylinder 1
6. Refrigerating machine oil lubricates each sliding part along this oil supply path.

Suction refrigerant gas passage 2 from oil sump 14 during normal operation
The pressure states of the oil supply passages 34 up to No. 7 are distributed as being sequentially reduced from the discharge pressure to the suction pressure. That is, the refrigerating machine oil containing refrigerant gas flowing from the oil sump 14 is first depressurized when passing through the narrow oil suction passage 11, and is refilled between the rotating passage 9 and the fixed passage 6, which are intermittently supplied with oil by the rotation of the drive shaft 8. When passing through the decompression device 15 of the simple shaft sealing device, the pressure is tertiaryly reduced, and when passing through the bypass passage 28, the pressure is finally reduced. The pressure in the oil supply passage 34 between the fixed passage 6 and the pressure reducing device 15 of the simple shaft seal device is reduced to an intermediate pressure between the discharge pressure and the suction pressure, and the pressure in the shaft seal device space 26 is reduced to the pressure in the suction pressure. The pressure has been reduced to a state close to that of the original pressure.

Furthermore, when the electromagnetic clutch 23 is de-energized and the compressor stops, the drive shaft 8 is subjected to a combined load of the spring force pressing the partition vane 18 against the piston 17 and the pressure load acting on the rear end surface of the partition vane 18. ,
Due to the action of the eccentric cam mechanism between the piston 17 and the partition vane 18, the angle between the top dead center angle of the piston 17 and the suction start point angle (the inner space of the cylinder in this angular range is determined by the angle where the piston 17 rotates in the opposite direction). , changes to compressed space).
Then, the fixed passage 6 and the rotating passage 9 are kept in a state of not communicating with each other. Further, as the pressure balance of the refrigeration cycle progresses, the pressure in the suction refrigerant gas passage 27 increases, and the refrigerant gas passes through the bypass passage 28 and enters the shaft sealing device space 26.
However, due to the action of the check valve 33, communication from the suction refrigerant gas passage 27 to the shaft sealing device space 26 is cut off. On the other hand, the refrigerating machine oil containing refrigerant gas trapped in the oil supply passage 34 from the pressure reducing device 15 of the simple shaft sealing device to the fixed passage 6 is gradually reduced in pressure by the pressure reducing device 15 of the simple shaft sealing device. It flows into the sealing device space 26 until the pressure is almost balanced. The shaft sealing device space 26 is filled with refrigerating machine oil and maintains the lowest pressure in the refrigerating cycle.

Further, the rotary body 10 having the rotary passage 9 is pressed against the thrust bearing press plate 7 by the differential pressure, thereby preventing refrigerating machine oil from flowing into the piston 17 from the oil sump 14 .

In the above embodiment, the rotary passage 9 was provided in the rotary body 10 at a position where the rotary passage 9 and the fixed passage 6 communicate only when the partition vane 18 was retracted the most. The stopping angle of the drive shaft 8 that drives the
When the partition vane 18 is moved back by at least half of its angle due to the rotation angle other than the angle of rotation (degrees), the rotation passage 9 is placed in a position where the rotation passage 9 and the fixed passage 6 communicate with each other.
may be provided on the rotating body 10.

Further, in the above embodiment, a lubricating system using the differential pressure between the oil reservoir and the suction refrigerant gas passage has been described, but the same effect can be applied when a pump device is provided at the end of the drive shaft for lubricating.

In addition, in the above embodiment, the rolling piston
Although the rotary compressor has been described, a slide vane rotary compressor or other compressors also function in a similar manner. In other words, in the case of a slide vane rotary compressor, even if the stop angle of the drive shaft is arbitrary when the compressor is stopped, reversal of the drive shaft due to refrigerant gas in the high pressure space flowing into the low pressure space within the cylinder is used. Then, the rotating body having a suitable angular positioning device is reversely rotated, and the opening/closing passage of the oil supply device including the oil suction passage can be closed.

Effects of the Invention As described above, according to the open refrigerant compressor of the present invention, the oil supply device having the opening/closing passage is arranged on the upstream side of the oil supply passage, and during normal operation, the oil sump on the discharge side is connected to the suction side. Refrigerating machine oil is intermittently supplied to each sliding part up to the shaft sealing space of the simple shaft sealing device while being depressurized in sequence through the pressure reducing device bypass passage.When the compressor is stopped, the oil supply path from the oil reservoir is cut off, and the refrigeration cycle As the pressure balance progresses, the pressure in the suction gas passage increases, liquid refrigerant returns to the suction gas passage, and due to the check action of the check valve provided in the bypass passage, liquid refrigerant flows from the suction gas passage to the shaft sealing device space. By cutting off the influx,
Prevents the viscosity of the refrigerating machine oil in the shaft seal device space from decreasing,
This prevents refrigerant from leaking from the airtight sliding surface of the shaft sealing device. In addition, since it prevents the refrigerating machine oil from flowing out in the shaft sealing device space, the sliding surface of the shaft sealing device remains submerged in oil even when the compressor is stopped, and a sufficient oil film is formed on the airtight sliding surface, preventing refrigerant leakage and refrigerating machine oil. Leakage is much less than during operation. Furthermore, even when the compressor is restarted, the shaft sealing device is sufficiently lubricated from the initial stage of startup, maintaining good sealing performance and improving durability. In addition, since there is no flow of refrigerating machine oil from the discharge side oil sump to the suction side cylinder when the compressor is stopped, liquid compression does not occur when the compressor is restarted, and operating efficiency is reduced due to the flow of refrigerating machine oil into the refrigeration cycle. There was no decrease in

In addition, sufficient refrigerating machine oil remains in the oil supply passage between the oil supply device and the shaft seal device space, so that sufficient oil can be supplied to each sliding part from the beginning of restarting the compressor, and there is no seizure during restart. In addition, since the bypass passage is a passage that opens when the differential pressure is higher than the set value, it is possible to prevent refrigerating machine oil from splashing out from the shaft seal device space to the suction gas passage when the compressor is restarted, and to prevent liquid compression within the cylinder. It has many excellent effects, such as preventing refrigerant leakage from the shaft sealing device due to temporary loss of refrigerating machine oil in the device space, as well as abrasion of the airtight sliding surface.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a conventional refrigerant compressor, and FIG. 2 is a graph showing the passage of time after the refrigerant compressor is stopped, the atmospheric pressure of the shaft sealing device, and the amount of refrigerant leakage.
FIG. 3 is a longitudinal cross-sectional view of an open compressor showing an embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line -- in FIG. 3, and FIG. This is an enlarged view. 1... Cylinder block, 2... Front plate, 3... Rear plate, 8... Drive shaft, 9...
...Rotating passage, 11...Oil suction passage, 12...Oil case (oil supply device), 14...Oil sump, 15...
Pressure reducing device, 17... Piston, 18... Partition vane, 22... Shaft sealing device, 26... Shaft sealing device space,
27...Suction refrigerant gas passage, 28...Bypass passage, 33...Check valve, 34...Refueling passage.

Claims (1)

[Claims] 1. A shaft sealing device for ensuring airtightness of the refrigerant and lubricating oil in the compressor main body, an oil supply passage equipped with a pressure reducing device to supply oil from the oil reservoir on the discharge side to the shaft sealing device space, and from the shaft sealing device space. A bypass passage communicating with the suction gas passage of the compressor main body is provided, and the upstream side of the oil supply passage has a passage driven by the drive shaft of the compressor, which is opened only when the rotating body is rotated, and the compressor is supplied with oil. When the drive shaft is stopped, the rotation body is provided with an oil supply device that blocks the oil supply passage by regulating the stop angle of the drive shaft, and the bypass passage includes:
An open type compressor provided with a check valve device that communicates only in one direction from the shaft seal device space to the suction gas passage when the differential pressure is equal to or higher than a set pressure difference.