JP2001041162A - Displacement fluid machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a bearing end part especially in the case where a bearing is under the eccentric contact condition by always generating proper lubricating fluid film pressure in the whole area in a bearing surface. SOLUTION: This displacement fluid machinery includes a mechanism part 13 for compressing or transferring fluid or taking out dynamic energy from working fluid, a shaft 7 for driving the mechanism part 13 or taking out dynamic energy, bearings 3f, 4f for supporting the shaft 7, a lubricating fluid supply hole 7f for supplying a lubricating fluid to a bearing part formed by the shaft 7 and the bearings 3f, 4f, and a storage chamber for storing lubricating fluid. In this fluid machinery, lubricating fluid supply grooves 31, 32 communicating with the lubricating fluid supply hole 7f are provided axially in the bearing part, and the lubricating fluid supply grooves 31, 32 are formed to be gradually decreased in sectional area as they go toward the ends of the supply grooves 31, 32 where lubricating fluid flows.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to a refrigerator or a refrigerant compressor for refrigeration or air conditioning, a gas compressor for air or helium, and an expander, a vacuum pump, a fluid pump, etc. which operate in the opposite direction. Related to a positive displacement fluid machine.

[0002]

2. Description of the Related Art A scroll fluid machine will be described as an example of a positive displacement fluid machine provided with a supply passage for supplying a lubricating fluid to a bearing portion.

The scroll fluid machine described in Japanese Patent Application Laid-Open No. 2-264182 has a fixed scroll and an orbiting scroll each provided with a disk-shaped head plate and a spiral wrap formed upright on the disk-shaped head plate. These are housed in a case having a suction port and a discharge port. The orbiting scroll has a cylindrical bearing mounted on the back side thereof, and this bearing is loosely fitted to a crank portion eccentric to the center of the crankshaft.
The shaft portion of the crankshaft is supported by upper and lower bearings mounted on the frame.

The pressure difference between the pressure in the storage chamber at the bottom of the case, which is the same as the discharge pressure, and the intermediate pressure in the back pressure chamber formed by the frame, the fine holes, and the orbiting scroll, is applied to the bearing. The power is supplied through a supply hole that rises up a supply path in the crankshaft, and is supplied to a supply hole that communicates with the supply path, and a supply groove that is provided on the surface of the crankshaft.

[0005] The lubricating fluid that has risen in the supply path flows into an oil chamber at the upper end of the crankshaft, and then flows into a supply groove provided in the axial direction on the surface of the crank section to lubricate the swing bearing section. The oil that has lubricated the slewing bearing and the main bearing is discharged into the back pressure chamber, then escapes into the compression chamber, is discharged into the case from the discharge hole, and returns to the storage chamber along the case wall and the like.

The lubricating fluid supplied to each bearing portion is a refrigerant mixture oil in which a refrigerant gas is dissolved. In the above publication, a supply groove formed in a crankshaft loosely fitted to a slewing bearing is shown, but in order to prevent foaming of dissolved refrigerant gas from oil in the supply groove, one of the supply grooves is provided. The other side is communicated with the back pressure chamber, but the other side is closed off and becomes smooth, in other words, a smooth portion is formed at the end of the groove and closed off.

In the scroll fluid machine disclosed in Japanese Patent Application Laid-Open No. 7-12068, the supply groove is provided in the axial direction on the surface of the crankshaft, and the position of the supply groove is such that the supplied oil is quickly drawn into the load surface. From the direction of the bearing load rotating in synchronization with the rotation of the crankshaft.
It is provided at the position of the advance angle of 0 °. Further, in order to suppress the bubbling of the refrigerant gas in the supply groove, a weir-shaped step is provided at the end of the supply groove to prevent a pressure drop due to a sudden decrease in the flow path area.

[0008]

However, in the above prior art, since both the smooth portion and the weir-shaped step are in the bearing, the lubricating fluid flows from the smooth portion or the weir-shaped step to the load surface of the bearing. Is difficult to supply, and the cross-sectional area of the supply groove is sharply reduced, so that foaming due to reduced pressure in the supply groove is prevented, but rapid foaming occurs in a smooth portion or a weir-shaped step portion, For this reason, in the case where the bearing portion is in the one-side contact condition, it is necessary to consider that the bearing may be damaged due to the shortage of the supply amount to the bearing end portion due to the blocking of the supply groove.

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive displacement type fluid machine which always generates an appropriate oil film pressure in the whole area of a bearing portion and prevents damage at the bearing end even when the bearing is in a one-sided condition. It is in.

[0010]

In order to achieve the above object, a positive displacement fluid machine according to the present invention comprises a mechanism for compressing or transferring a fluid or extracting mechanical energy from a working fluid; A shaft for driving the mechanical portion or extracting mechanical energy, a bearing for supporting the shaft, a lubricating fluid supply hole for supplying a lubricating fluid to a bearing portion including the shaft and the bearing, In a positive displacement fluid machine having a storage chamber for storing fluid, a lubricating fluid supply groove communicating with a lubricating fluid supply hole is provided in the bearing portion in the axial direction,
The cross-sectional area is formed so as to decrease toward the end of the supply groove through which the lubricating fluid flows.

Preferably, the lubricating fluid supply groove is formed such that the groove width is constant and the groove depth is reduced toward the end of the supply groove through which the lubricating fluid flows, so that the sectional area decreases. is there.

Preferably, the lubricating fluid supply groove is formed such that both the groove width and the groove depth decrease toward the end of the supply groove through which the lubricating fluid flows.

More preferably, the lubricating fluid supply groove is such that an end of the lubricating fluid supply groove is closed in a bearing portion.

Still preferably, the length of the sealing portion is in the range of 1 to 20% of the bearing width.

In order to achieve the above object, a positive displacement type fluid machine according to the present invention comprises a mechanism for compressing or transferring a fluid or extracting mechanical energy from a working fluid, and a mechanism for the mechanism. A shaft for driving or taking out mechanical energy, a bearing for rotatably supporting the shaft, a lubricating fluid supply hole for supplying a lubricating fluid to a bearing unit composed of the shaft and the bearing, and storing the lubricating fluid In the positive displacement fluid machine including a storage chamber, a lubricating fluid supply groove communicating with a lubrication fluid supply hole communicating with the storage chamber is provided in the bearing portion in the axial direction of the shaft, and an end of the supply groove through which the lubricating fluid flows is provided. It is sealed in the bearing part, and the length of the sealed part is 1 to 20% of the bearing width.
In the range.

[0016] Preferably, the lubricating fluid supply groove is provided on an outer surface of the shaft or an inner surface of the bearing where no load is applied.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of a positive displacement fluid machine according to the present invention, specifically, an example of a horizontal hermetic scroll compressor. FIG. 1 is a vertical sectional view of a hermetic scroll compressor. The hermetic scroll compressor is a high-pressure chamber type hermetic scroll compressor in which the pressure in the compressor case becomes a discharge pressure. The diameter of the compressor is approximately 10 mm to 1000 mm. is there.

First, an outline of the configuration will be described. The fixed scroll member 2 housed in the case 1 has its end plate 2
A scroll wrap 2b is formed at a, and a discharge hole 2c is opened at the center. A plurality of flow grooves 2j through which gas and a lubricating fluid (in this embodiment, lubricating oil is used) are provided on the outer circumference of the fixed scroll member 2. The orbiting scroll member 3 is formed with a scroll wrap 3b having an involute or an algebraic spiral as a basic line on its end plate 3a.
On its back surface, a swivel bearing 3f and swivel Oldham grooves 3d, 3e
Are provided.

The frame 4 is provided with a frame Oldham groove (not shown) for disposing the Oldham ring 5 inside the frame 4 and the orbiting scroll member 3. Further, a shaft seal 4a and a main bearing 4f are provided at a central portion of the frame 4, and a shaft thrust surface 4b for receiving a force in a thrust direction of the shaft 7, which will be described later, is provided. Further, on the outer peripheral surface of the frame 4, a plurality of flow grooves 4 c serving as gas and lubricating fluid channels are provided, and communicate with the flow grooves 2 j of the fixed scroll member 2. The Oldham ring 5 is provided with a frame projection (not shown) on one surface, and a turning projection 5 on the other surface.
c and 5d are provided.

The shaft 7 is provided therein with a shaft lubrication fluid supply hole 7a, a main bearing lubrication fluid supply hole 7b, a shaft seal lubrication fluid supply hole 7c, and a sub-bearing lubrication fluid supply hole 7f. A balance holding portion 7e having an enlarged diameter is provided at an upper portion of the shaft 7, and the balance holding portion 7e
The shaft balance 14 is press-fitted into the shaft. Reference numeral 15 denotes a suction pipe.

The motor 10 includes a rotor 8 and a stator 9.
The stator 9 is attached to the case 1. The motor chamber 20 is separated from the storage chamber 26 by the bearing support plate 11, and the storage chamber 26 stores the lubricating fluid 22 to be supplied to the sliding portion of the bearing. An auxiliary bearing 24 is provided on the bearing support plate 11.
Is mounted, and supports the shaft 7 together with the main bearing 4f.

A differential pressure control mechanism 30 is provided between the back side conduction path 2i and the suction side conduction path 2h, and the differential pressure control mechanism 30 is connected to the fixed scroll member 2, the orbiting scroll member 3, and the frame 4. This is for controlling the back pressure in the back pressure chamber 29.

Reference numeral 13 denotes a compression mechanism, which basically comprises the fixed scroll member 2 and the orbiting scroll member 3. In this embodiment, since the displacement type fluid machine is a scroll compressor, it serves as a compression mechanism, but when it is used as a pump for simply transferring fluid, it serves as a pump mechanism, and also from a working fluid. When used as a drive source such as a motor for extracting energy, it serves as a drive mechanism.

Next, the operation will be described. First, the operation immediately after starting the compressor will be described. By driving the motor 10, the shaft 7 rotates, and the orbiting scroll member 3 makes orbital motion. The orbiting scroll member 3 is prevented from rotating due to the presence of the Oldham ring 5. By this operation, the gas in the suction chamber 18 at the outer peripheral portion of the region where the two scroll wraps 2b and 3b mesh with each other is confined in the compression chamber 6 formed between the two scroll members 2 and 3, and is compressed and discharged. 2c is discharged to the fixed side rear chamber 19.
The gas discharged from the discharge hole 2c to the fixed rear chamber 19 is:
Flow groove 2 around fixed scroll member 2 and frame 4
It passes through j and 4c and flows into the space between the motor 10 and the frame 4 in the motor chamber 20.

The gas flowing into the space between the motor 10 and the frame 4 further reaches the bearing support plate 11 side of the motor chamber 20 through a gap between the rotor 8 and the stator 9. The compressed gas that has reached the bearing support plate 11 accumulates in the motor chamber 20, and the pressure in the motor chamber 20 increases. This pressure increase is caused by the motor chamber 20 and the fixed-side rear chamber 1.
9 is pressurized on the fluid surface of the lubricating fluid 22 stored in the lower part of the cylinder 9. As a result, the lubricating fluid 22 flows into the storage room 26 through the lower passage opening 11a of the bearing support plate 11, and the storage room 26
The fluid level on the side rises. When the fluid level of the motor chamber 20 reaches the uppermost portion of the lower flow port 11a, the lower flow port 11a serves as a flow path, and gas flows from the motor chamber 20 to the storage chamber 26. At this time, the gas is blown out from below the lubricating fluid 22 in the storage chamber 26, rises as bubbles, and rises.
The gas that has risen to the surface of the compressor is discharged from the discharge pipe 16 to the outside of the compressor. As described above, since a large amount of the lubricating fluid 22 can be stored in the compressor, the fluid does not run out.

The pressure in the back pressure chamber 29 immediately after the start is close to the suction pressure. Due to the pressure difference between the pressure in the back pressure chamber 29 and the pressure in the storage chamber 26 which is close to the discharge pressure, the lubricating fluid in the storage chamber 26 enters the supply cap 27 from the lubricating fluid supply pipe 23 and is supplied to the shaft lubricating fluid supply hole 7a. Is done. Part of the lubricating fluid that has entered the shaft lubricating fluid supply hole 7a is supplied to the bearing portion of the sub-bearing 24 through the sub-bearing lubricating fluid supply hole 7f when centrifugal force is applied, and the other part is similarly centrifuged. The force is applied to the shaft seal 4a through the shaft seal lubricating fluid supply hole 7c, the other part is supplied to the main bearing 4f through the main bearing lubricating fluid supply hole 7b by centrifugal force, and the rest is swiveled. After reaching the center of the back surface of the scroll member 3, it is supplied to the orbit bearing 3f by the differential pressure and the centrifugal force. As a result, a lubricating fluid chamber 28 to which a pressure equal to the discharge pressure is applied is formed at the center of the back surface of the orbiting scroll member 3.

The lubricating fluid supplied to the main bearing 4f and the slewing bearing 3f enters the back pressure chamber 29 after lubricating the bearing portion.
Since the average pressure of the lubricating fluid in the bearing is higher at a pressure closer to the pressure of the storage chamber 26 than the pressure of the back pressure chamber 29, it is blown out to the back pressure chamber 29. As a result, the temperature rise and the pressure suddenly decrease due to the friction of the bearing portion, so that the solubility of the gas component decreases, and a foaming phenomenon occurs in which the gas dissolved in the lubricating fluid is vaporized at a stretch. Further, the lubricating fluid becomes fine droplets due to the bubbling of the gas component, moves along the flow of the gas, and moves toward the orbiting scroll member 3, so that the lubricating fluid also flows in that direction. An Oldham ring 5 is provided in the path from the main bearing 4f and the orbiting bearing 3f to the orbiting scroll member 3, and a sliding portion of the Oldham ring 5 is also supplied with lubricating fluid.

Immediately after startup, the amount of gas flowing into the back pressure chamber 29 sharply increases, the flowing gas flows into the suction chamber 18, and the lubricating fluid also flows into the suction chamber 18. Suction chamber 18
Lubricating fluid flows into the compression chamber 6 having a slight gap in the axial direction, and the sealing performance of the compression chamber 6 is improved.
And has the effect of promoting an increase in discharge pressure. Thereafter, the lubricating fluid flows out from the discharge holes 2c into the fixed-side rear chamber 19 together with the gas. Since the amount of lubricating fluid in the flowing fluid is large and partially forms a seal portion, the back pressure chamber 29
The amount of gas and lubricating fluid flowing out of the fixed side rear chamber 19 is smaller than the amount of gas and lubricating fluid flowing into the chamber, and the pressure in the back pressure chamber 29 rises sharply.

The discharge pressure rises, and the pressure in the lubricating fluid chamber 28 also rises, and the force for pressing the orbiting scroll member 3 against the fixed scroll member 2 sharply increases. The pressing force in a short time becomes greater than the separating force, and the orbiting scroll member 3 is pressed against the fixed scroll member 2.
As a result, the gap between the tooth tip and the tooth root between the scroll wraps is reduced, the sealing performance of the compression chamber 6 is improved, the amount of internal leakage of gas during compression is reduced, and the performance is lower than immediately after startup. Is shifted to the normal operation with a drastically improved state.

Next, a description will be given of a normal operation in a state where the orbiting scroll member 3 is pressed against the fixed scroll member 2. Except that all the gas and lubricating fluid flowing into the back pressure chamber 29 do not directly flow into the suction chamber 18, the operation is the same as that immediately after the compressor is started. The gas and the lubricating fluid flowing into the back pressure chamber 29 move around the side surface of the orbiting scroll member 3, and a part of the gas flows into the suction chamber 18.
However, the side of the orbiting scroll member 3 is
9, the pressure in this region is substantially equal to the pressure in the back pressure chamber 29. Therefore, the back pressure chamber 29
Most of the gas and lubricating fluid flowing into the
It flows into the suction chamber 18 through the differential pressure control mechanism 30 via i. Here, the differential pressure control mechanism 30 opens the internal valve when the pressure in the back pressure chamber 29 becomes higher than the suction pressure by a predetermined value, so that the back pressure chamber 29 is connected to the suction side conduction path 2 h and the back side conduction path 2.
It communicates with the suction chamber 18 through i.

As a result, most of the gas and the lubricating fluid flowing into the back pressure chamber 29 are supplied to the back side conduction path 2 i and the differential pressure control mechanism 3.
0, and flows into the suction chamber 18 sequentially through the suction-side conduction path 2h. Then, the gas in the compression chamber 6 is mixed with the gas in the compression chamber 6.
Is transferred to the center of the wrap while improving the sealing property of the wrap, and is discharged from the discharge hole 2c. Therefore, the lubricating fluid supplied to the slewing bearing 3f and the main bearing 4f is entirely contained in the compressed gas discharged from the discharge hole 2c.

Further, the gas and the lubricating fluid are supplied to the flow grooves 2
The motor chamber 20 is entered through j and 4c. Thereafter, the lubricating fluid and the gas are separated in the storage chamber 26 in the same manner as when the compressor is started, and the lubricating fluid is stored in the storage chamber 26.

Next, the slewing bearing and the main bearing will be described. FIG. 2 is an enlarged view of a slewing bearing portion and a main bearing portion of FIG. 1,
FIG. 3 is a longitudinal sectional view when FIG. 2 is viewed from the left side direction.

In the same figure, an axial lubricating fluid supply groove 3 is provided in each of the swivel bearings to supply a lubricating fluid to each bearing.
1. An axial lubricating fluid supply groove 32 is provided on the shaft surface in the main bearing portion. That is, in the main bearing portion, the axial lubricating fluid supply groove 32 is provided from the main bearing lubricating fluid supply hole 7b toward the bearing end on the side of the back pressure chamber 29, which is the flow direction of the lubricating fluid. In the revolving bearing portion, an axial lubricating fluid supply groove extends from the lubricating fluid chamber 28 communicating with the shaft lubricating fluid supply hole 7a toward the bearing end on the back pressure chamber 29 side, which is also in the lubricating fluid flow direction. 31 are provided.

Each of the axial lubricating fluid supply grooves 31 and 32 has a cross-sectional area of the flow passage decreasing toward the bearing end on the back pressure chamber 29 side in order to prevent gas components from foaming in the lubricating fluid supply groove. In this case, the plane and the cross section are formed in a triangular shape. The axial lubricating fluid supply grooves 31 and 32 are provided at positions advanced by about 90 ° in the rotational direction with respect to the directions of the fluid forces acting on the slewing bearing 3f and the main bearing 4f, respectively. The axial lubricating fluid supply groove 31 for 3f and the axial lubricating fluid supply groove 32 for the main bearing 4f are located at opposite phase angles.

When the motor 10 is driven to rotate and the orbiting scroll member 3 makes orbital movement with respect to the fixed scroll member 2 to compress the suction gas, a load due to the compressive action of the fluid is applied to the shaft 7 via the orbiting scroll member 3. Join. Therefore, a load is also applied to the main bearing 4f and the slewing bearing 3f that support the shaft 7. Since these loads rotate in synchronization with the shaft 7, there is no change in the angular position of the load applied to the shaft 7. Therefore, the lubricating fluid is supplied from the lubricating fluid so that an optimal lubricating fluid film pressure adapted to the load is generated from the axial lubricating fluid supply grooves 31 and 32 always located at a position advanced by about 90 ° with respect to the load application position. Can be supplied.

The axial lubricating fluid supply grooves 31 and 32 have a cross-sectional area decreasing toward the bearing end in the lubricating fluid flow direction and are narrowed, so that the axial lubricating fluid supply grooves 31 and 32 are narrowed. The pressure of the lubricating fluid that has entered inside is maintained at the discharge pressure, and gas bubbling in the lubricating fluid due to reduced pressure hardly occurs. Further, as shown in FIG. 3, the cross-sectional shape of the axial lubricating fluid supply grooves 31 and 32 is
It is expected that the pressure at the bearing end on the back pressure chamber 29 side will be higher than the discharge pressure due to the wedge effect due to the flow of the lubricating fluid because of the triangular wedge shape toward the bearing end on the side. .

Further, in this embodiment, since the axial lubricating fluid supply grooves 31 and 32 are formed near the bearing end on the back pressure chamber 29 side, the lubricating fluid is supplied over the entire area up to the bearing end. The lubricating fluid supply pressure at the bearing end does not decrease due to the wedge effect in the lubricating fluid supply groove. Therefore, it is possible to prevent gas components from foaming due to rapid pressure reduction at the bearing end and to prevent damage to the bearing due to insufficient lubricating fluid supply at the bearing end.

Furthermore, since the structure is such that the sectional area of the lubricating fluid supply groove does not change suddenly, disturbance of the flow of the lubricating fluid throughout the bearing portion is suppressed, and it is necessary to form fine bubble nuclei which are the starting points of foaming. Since the amount of heat energy generated can be reduced, the refrigerant in the lubricating fluid in the bearing becomes supersaturated, and foaming can be suppressed.

For the above reasons, even in a positive displacement type fluid machine, such as a scroll compressor, in which a contact of a bearing is unavoidable due to its structure, foaming of gas components in the bearing can be prevented and the bearing on the back pressure chamber side can be prevented. By improving the lubricating fluid supply pressure at the end, damage to the bearing piece can be prevented, and reliability is improved.

Since there is no stepped portion in the axial lubricating fluid supply grooves 31 and 32, abrasion powder of the sliding portion and foreign matter from the outside of the compressor are mixed into the compressor. Even when the lubricating fluid supply grooves 31 and 32 enter the lubricating fluid supply grooves 31 and 32 through the lubricating fluid supply hole 7a, it is possible to prevent the accumulation of abrasion powder and foreign matter at the steps. If abrasion powder or foreign matter accumulates in the lubricating fluid supply groove, the lubricating fluid is supplied from there to the bearing load surface together with the lubricating fluid, causing local abrasion due to the foreign matter and reducing reliability. In this case, the lubricating fluid supply grooves 31 and 32 gradually decrease in cross-sectional area, and since there is no step, even if abrasion powder or foreign matter enters the lubricating fluid supply groove, it can be dispersed and discharged to the outside of the bearing. In addition, bearing damage can be prevented.

Further, axial lubricating fluid supply grooves 31, 32
Since the lubricating fluid supply groove has a triangular plane and cross section, the lubricating fluid supply groove can be easily processed by grinding, milling, or the like. Since the conventional lubricating fluid supply groove has a flat portion or a weir-like step portion, a step of deburring the step portion is necessary after the groove processing. , 32 do not have a step because they do not have a step, so that workability can be improved and manufacturing cost can be reduced.

The lubricating fluid supply groove may not have a triangular shape depending on the processing method, but may have a trapezoidal shape in which the lubricating fluid supply groove slightly communicates with the bearing end face, or a shape combining curved surfaces. In this case, the same effect as that of the lubricating fluid supply groove can be obtained.

Furthermore, since the axial lubricating fluid supply grooves 31 and 32 according to the present embodiment have no steps, there is no stress concentration portion where cracks are likely to occur, so that material destruction hardly occurs and reliability is improved. I do.

As described above, according to this embodiment, the cross-sectional area of the lubricating fluid supply groove provided in the shaft is reduced in the direction of the flow of the lubricating fluid, so that the bubbling phenomenon of the gas component dissolved in the lubricating fluid can be prevented. In addition, since the lubricating fluid that requires the most lubricating fluid at the time of one-sided contact can be sufficiently lubricated, the load-bearing capacity (load capacity) of the bearing has been significantly improved, and a positive displacement fluid machine with improved reliability and performance has been developed. Can be provided.

FIG. 4 shows a second embodiment of the positive displacement fluid machine according to the present invention. Specifically, the non-orbiting scroll member is movable in the axial direction, and the back pressure chamber is provided on the side of the end plate opposite to the compression chamber. And a compressor in which the member supporting the non-orbiting scroll member in the required operating pressure condition range is a orbiting scroll member, that is, a vertical non-orbiting float type scroll compression in which the non-orbiting scroll member is pressed against the orbiting scroll member. This is a low pressure chamber type machine.

FIG. 1 is a longitudinal sectional view of the compressor. First, an outline of the structure will be described. The non-orbiting scroll member 2 'housed in the case 1' has a scroll wrap 2b 'formed on its end plate 2a' and a center base 2e 'at the center of the back surface.
And a discharge hole 2c 'and a plurality of bypass holes 2d' are provided on the upper surface thereof. A bypass valve plate 12 'is fixed to the bypass hole 2d'. Further, a back recess 2f 'is provided in the center base portion 2e', and a differential pressure control mechanism 30 'is provided near the periphery of the back recess 2f', and the differential pressure control mechanism 30 'adjusts the excessive suction pressure. It is a mechanism for doing. The orbiting scroll member 3 ′ has a scroll wrap 3 b ′ formed on a head plate 3 a ′, and the orbital Oldham grooves 3 d ′ and 3 e ′, a slewing bearing 3 f ′ and a thrust surface 3
c ′ are arranged.

The frame 4 'is provided with a mounting portion for mounting the non-orbiting scroll member 2' on the outer peripheral portion and a sliding thrust bearing surface for receiving the thrust surface 3c 'inside the mounting portion. Z) is also provided. Also, a plurality of suction grooves (not shown) are provided on the outer peripheral portion.
And a shaft seal 4a 'and a main bearing 4f' in the center.
And a shaft thrust surface 4b 'for receiving the shaft 7' is provided on the scroll side. A lubricating fluid discharge passage 4h 'is provided so as to pass from the lowest portion of the upper surface of the frame 4' to the lower surface of the frame. A lateral hole 4g 'is opened from the shaft seal 4a' and the main bearing 4f 'toward the space on the side surface of the frame. A frame projection (not shown) is provided on one surface of the Oldham ring 5 ', and a turning projection (not shown) is provided on the other surface.

The pressure partition 25 'is provided with a discharge opening 25a' at the center and a discharge back flow path 25b 'with a throttle communicating the lower surface and the upper surface. Here, another piece having a small diameter hole is press-fitted. Shaft 7 '
Are provided therein with a shaft lubrication fluid supply hole 7a ', a main bearing lubrication fluid supply hole 7b', a shaft seal lubrication fluid supply hole 7c ', and a sub bearing lubrication fluid supply hole 7f'. A balance holding portion 7e 'having an enlarged diameter is provided at an upper portion of the shaft 7', and a shaft balance 14 'is press-fitted therein.

The motor chamber 20 'is separated from the storage chamber 26' by a bearing support plate 11 'having a lower passage opening 11a'. The storage chamber 26 'has a lubricating fluid 22' to be supplied to the sliding portion of the bearing. Is stored. An auxiliary bearing 23 'is attached to the bearing support plate 11', and supports the shaft 7 'together with the main bearing 4f'. In the compressor of the present embodiment, the supply of the lubricating fluid to the bearing is a forced supply system,
Therefore, the lubricating fluid supply pump 1
7 'is attached.

The motor 10 'composed of the rotor 8' and the stator 9 'is the same as that of the first embodiment and will not be described.

As in the first embodiment, reference numeral 13 'denotes a compression mechanism, which basically comprises a fixed scroll member 2' and an orbiting scroll member 3 '. In this embodiment,
Since the displacement type fluid machine is a scroll compressor, it becomes a compression mechanism, but when used as a pump for simply transferring fluid, it becomes a pump mechanism, and also for extracting mechanical energy from working fluid. When used as a drive source such as a motor, the drive mechanism is the same as in the first embodiment.

Next, the operation will be described. The gas entering the motor chamber 20 'from the suction pipe 15' passes through a suction groove 4r 'provided in the frame 4' and sucks the gas into the suction chamber 18 '.
Sucked into. The air is compressed in the compression chamber 6 'by the orbiting motion of the orbiting scroll member 3' from the suction chamber 18 ', and is discharged from the discharge hole 2c' to the upper non-orbiting rear chamber 19 'of the non-orbiting scroll member 2'. Exit from the compressor from 16 '.

The non-orbiting scroll member 2 'is provided with a compression chamber 6'.
Although a separating force in a direction away from the orbiting scroll member 3 ′ is received by the internal gas pressure, it is pressed against the orbiting scroll member 3 ′ by a pressing force by the rear recess 2 f ′. That is, the urging force of the non-orbiting scroll member 2 'is given from the rear recess 2f'. On the other hand, the orbiting scroll member 3 'has no pressing force and is supported by a sliding thrust bearing (not shown) on the orbiting back surface. As a result, the gap between the tooth tip and the tooth bottom of both scroll members does not increase, and the compression operation can be continued.

Here, the pressure in the rear recess 2f 'is controlled by a differential pressure control mechanism 30'. This differential pressure control mechanism 30 '
Has the same structure as that of the first embodiment, except that the pressure is introduced by the compressible gas and the lubricating fluid passing through the bearing. As described above, an optimal design can be achieved by considering only the pressure introduction into the rear recess 2f 'corresponding to the back pressure chamber 29 in the first embodiment.

The lubricating fluid 22 'stored in the storage chamber 26' located at the bottom of the compressor is supplied by the lubricating fluid supply pump 17 'through the shaft lubrication fluid supply hole 7a' to the slewing bearing 7c '. . Further, the lubricating fluid 22 'is supplied to the main bearing 4a' via the main bearing lubricating fluid supply hole 7b '. The supplied lubricating fluid enters the suction chamber 18 'while lubricating the sliding thrust bearing after entering the swirl back pressure chamber 21', and the other passes through the lubricating fluid discharge passage 4h 'to the motor chamber 20'. And collects in a storage room 26 'located at the bottom of the compressor.

Next, the slewing bearing and the main bearing will be described. The slewing bearing 3f 'is provided with a lubricating fluid supply groove 31' having the same shape as the axial lubricating fluid supply groove in the first embodiment described above with reference to FIGS. 4f 'is different from the first embodiment in that axial lubricating fluid supply grooves 32' are provided on the shaft surface in both directions from the main bearing lubricating fluid supply holes 7 'toward both ends of the main bearing. The reason is that in the main bearing 4f ', the flow of the lubricating fluid from the main bearing lubricating fluid supply hole 7b' is transmitted not only to the bearing end on the turning back pressure chamber 21 'side but also to the bearing end on the shaft seal 4a' side. It is to head. Further, the axial lubricating fluid supply grooves 31 ', 32'
In order to prevent gas components from foaming in the lubricating fluid supply groove, the axial lubricating fluid supply grooves 3 are formed so that the cross-sectional area of the flow path decreases toward the bearing end similarly to the first embodiment.
The planes and cross sections of 1 ′ and 32 ′ are formed in a substantially triangular shape. Further, the axial lubricating fluid supply grooves 31 ', 3
2 ′ is provided at a position advanced by about 90 ° in the rotation direction from the position of the fluid force acting on each bearing portion, and therefore,
The lubricating fluid supply groove 31 'for the slewing bearing 3f' and the lubricating fluid supply groove 32 'for the main bearing 4f' are at opposite phase angles.

In the case of the present embodiment, since the pressure of the storage chamber 26 'is equal to the suction pressure because of the low pressure chamber type compressor, the amount of the refrigerant gas dissolved in the lubricating fluid 22' is limited to the high pressure chamber of the first embodiment. The amount of gas component foaming is small compared to the case of the system. However, there is always a depressurizing section together with a high-pressure section caused by the generation of dynamic pressure in the bearing, and foaming of gas components always occurs. Therefore, the effects of the lubricating fluid supply grooves 31 'and 32' in this embodiment are exactly the same as those in the above embodiment, and are also effective in a low pressure chamber type compressor.

The axial lubricating fluid supply grooves of the first embodiment and the present embodiment are provided at angular positions advanced by about 90 ° in the rotational direction from the position of the fluid force acting on the bearing. May be provided at a leading angle position such as 180 ° or 270 °. If the axial lubricating fluid supply groove is provided in the advance angle position range of about 90 ° to 300 °, the lubricating fluid will be supplied to the depressurized region in the bearing, and the effect of further preventing the pressure drop will be exhibited.

FIG. 5 shows a positive displacement fluid machine according to a third embodiment of the present invention, in which a main bearing and a swivel bearing are partially cut away. This embodiment differs from the first and second embodiments in that the axial lubricating fluid supply groove 32 has a deep groove shape whose depth is greater than the width, and is closest to the main bearing lubricating fluid supply hole 7b. This is to make the part deepest and shallow as you move away. However, as in the first embodiment, the flow path is provided so that the cross-sectional area decreases toward the upper end of the bearing. In the case of the present embodiment, the cross-sectional area of the flow channel can be made larger than in the first and second embodiments. Therefore, when the lubricating fluid that lubricates the bearing flows into the working chamber without any problem, or when the amount of lubricating fluid supplied to the bearing is increased due to the problem of heat generation in the bearing and the like, the lubricating fluid of the present embodiment is used. The supply groove is effective.

FIG. 6 is a vertical sectional view of a main bearing and a slewing bearing according to a fourth embodiment of the displacement type fluid machine according to the present invention.

This embodiment is different from the above embodiments in that sealing portions 31a and 32a are provided on the shaft 7 near the bearing end of the axial lubricating fluid supply groove 32, which is the lubricating fluid outlet. . That is, the sealing portion 31a is provided near the bearing end of the axial lubricating fluid supply groove 32 of the shaft 7 at the portion corresponding to the main bearing 4f, and the axial lubricating fluid is supplied to the shaft 7 at the portion corresponding to the swing bearing 3f. A sealing portion 32a is provided near the bearing end of the groove 31.

In general, if a one-sided operation occurs due to the bubbling of the gas component due to the rapid pressure reduction in the sealing portions 31a and 32a and the insufficient supply of the lubricating fluid from near the bearing end, the bearing will be damaged by the contact.

Also, in the case of the scroll compressor as in the above embodiment, or in other types of positive displacement fluid machines, when the bearing load becomes a rotational load or a variable load, a repeated load is applied to the bearing portion. In such a case, fatigue wear or fatigue fracture of the bearing surface may become dominant as bearing damage. In particular, at the time of one-side contact, the lubricating fluid film pressure becomes maximum near the shaft end, and a much larger pressure acts than at the time of parallel contact. However, in the present embodiment, the above-described damage and the like are avoided from being configured as described below.

The reason will be described in detail with reference to FIG. The lubricating fluid film pressure at the time of one-side contact is as shown in FIG. The vertical axis represents the lubricating fluid film pressure (relative value), and the horizontal axis represents the dimensionless bearing width standardized by the bearing width. A curve A in the figure is a case of a bearing material (for example, a resin material such as Teflon) which is easily deformed, and a curve B is a case of a virtual material having no deformation.

As shown in the figure, the maximum value of the lubricating fluid film pressure is located about 5 to 25% of the bearing width at a position closer to the center from the bearing end face.
Emitted from this maximum pressure portion. Therefore, in order to prevent pressure reduction in the lubricating fluid supply groove when the lubricating fluid supply amount decreases, the lubricating fluid supply groove is extended from the maximum position to the bearing end side from the maximum position. This allows for the supply of the lubricating fluid to the places where damage is most likely to occur. In addition, a sudden decrease in the pressure of the lubricating fluid or an increase in the flow rate of the lubricating fluid in the lubricating fluid supply groove is prevented by the closing portion 31.
a, 32a, and can prevent foaming of gas components in the lubricating fluid.

That is, the width C of the sealing portions 31a and 32a
By setting (see FIG. 6) 1 to 20% of the bearing width C + D that is effectively acting as a bearing, an effective sealing action can be obtained.

In the embodiment of FIG. 6, the sealing portions 31a and 32a are combined with the rectangular lubricating fluid supply grooves 31 and 32. However, in combination with the lubricating fluid supply groove having the shape shown in FIG. Has the same effect.

Although not shown, also in the first and second embodiments, the lubricating fluid supply groove is closed at the end of the lubricating fluid supply groove in which the lubricating fluid flows in the bearing portion. The same effect can be obtained even if the length is within the range of 1 to 20% of the bearing width.

As described above, according to the above-described embodiment, it is possible to prevent damage to the end of the bearing at the time of one-sided contact, and to generate the lubricating fluid film pressure in the bearing by preventing the gas component from foaming in the sliding bearing. Is sufficiently performed, and an effect of significantly increasing the load resistance (load capacity) of the bearing can be obtained.

Although the above embodiment has been described with reference to a closed scroll compressor as an example, the same applies to a case where the present invention is applied to a displacement type fluid machine such as a pump or an expander as well as a compressor other than the scroll type. The effect is obtained. Similar effects can be obtained not only when a lubricating fluid or the like is used as the bearing lubricating fluid, but also in a process fluid lubricated bearing that uses the working fluid itself for lubrication.

Further, the lubricating fluid supply groove has been described as an axial groove, but the same effect can be obtained when the present invention is applied to a spiral groove in which a screw pump action is exerted by rotation of a shaft.

[0073]

As described above, according to the present invention,
A positive displacement type that always generates an appropriate lubricating fluid film pressure in the entire area of the bearing surface, and supplies lubricating fluid to the bearing end even when the bearing is in one-sided contact condition, preventing damage at the bearing end. A fluid machine can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a high-pressure chamber type horizontal scroll compressor according to a first embodiment of the positive displacement fluid machine of the present invention.

FIG. 2 is an enlarged view of a main bearing portion of FIG.

FIG. 3 is a longitudinal sectional view when FIG. 2 is viewed from a left side direction.

FIG. 4 is a cross-sectional view of a low-pressure chamber type vertical scroll compressor according to a first embodiment of the positive displacement fluid machine of the present invention.

FIG. 5 shows a third embodiment of the positive displacement fluid machine according to the present invention, in which a main bearing and a swivel bearing are partially cut away. .

FIG. 6 is a longitudinal sectional view of a main bearing and a swivel bearing in a fourth embodiment of the positive displacement fluid machine according to the present invention.

FIG. 7 is an explanatory diagram of a lubricating fluid film pressure at the time of one-side contact of a bearing.

[Explanation of symbols]

1, 1 'case 2 fixed scroll member 2' non-orbiting scroll member 2a 2a 'end plate 2b 2b' scroll wrap 2c 2c 'discharge hole 2d' bypass hole 2
e ': central base portion, 2f': rear concave portion, 2h: suction side conductive path, 2i ... rear side conductive path, 2j ... circulation groove 3, 3 '... revolving scroll member, 3a, 3a' ... end plate,
3b, 3b ': scroll wrap, 3c': thrust surface, 3d, 3d ', 3e, 3e': turning Oldham groove, 3
f, 3f '... slewing bearing 4, 4' ... frame, 4a, 4a '... shaft seal, 4b,
4b ': shaft thrust surface, 4c: flow groove, 4f, 4
f ': Main bearing, 4g': Horizontal hole, 4h ': Lubricating fluid discharge path, 4r': Suction groove 5, 5 '... Oldham ring, 5c, 5d: Revolving protrusion 6, 6' ... Compression chamber 7, 7 '... shaft, 7a, 7a' ... shaft lubrication fluid supply hole, 7, 7b '... main bearing lubrication fluid supply hole, 7c, 7
c ': shaft seal lubricating fluid supply hole, 7f, 7f': auxiliary bearing lubricating fluid supply hole, 7e, 7e ': balance holding portion 8, 8' ... rotor 9, 9 '... stator 10, 10' ... motor 11, 11 ': auxiliary bearing support plate, 11a: lower passage opening 12': bypass valve plate 13, 13 ': compression element 14, 14': shaft balance 15, 15 ': suction pipe 16, 16': discharge pipe 17, 17 '... Lubricant fluid supply pump 18,18' ... Suction chamber 19 ... Fixed side rear chamber, 19 '... Non-rotating side rear chamber 20,20' ... Motor chamber 22,22 '... Lubricant fluid 23,23' ... Lubricant fluid supply Pipes 24, 24 '... sub-bearings 25, 25' ... pressure bulkheads, 25a '... discharge openings, 25
b ': discharge back flow path 26, 26' ... storage chamber 27 ... lubricating fluid supply cap 28 ... lubricating fluid chamber 29 ... back pressure chamber 30, 30 '... differential pressure control mechanism 31, 31' ... axial direction on the slewing bearing side Lubricating fluid supply grooves 32, 32 '... axial lubricating fluid supply grooves on the main bearing side

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Isao Hayase 502, Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. Inside the Machinery Research Laboratory (72) Inventor Yugo Mukai 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling & Heating Dept., Hitachi, Ltd. F-term (ref.) 3H003 AA05 AB03 AB05 AC03 BD03 BD07 CA02 3H029 AA02 AA15 AA21 AB02 AB03 AB04 BB06 BB44 BB50 CC16 CC17 CC22 CC33 3H039 AA02 AA06 AA12 BB05 BB11 CC09 CC10 CC19 CC27 CC42

Claims (7)

[Claims] 1. A mechanism for compressing or transferring a fluid or extracting mechanical energy from a working fluid, a shaft for driving the mechanism or extracting mechanical energy, and a bearing for supporting the shaft. When,
In a positive displacement type fluid machine including a lubricating fluid supply hole for supplying a lubricating fluid to a bearing unit including the shaft and the bearing, and a storage chamber for storing the lubricating fluid, the lubricating fluid communicates with the storage chamber in the bearing unit. A volume type wherein a lubricating fluid supply groove communicating with the supply hole is provided in the axial direction, and the lubricating fluid supply groove is formed so that a sectional area decreases toward an end of the supply groove through which the lubricating fluid flows. Fluid machinery. 2. The lubricating fluid supply groove is formed so that the groove width is constant and the groove depth is reduced toward the end of the supply groove through which the lubricating fluid flows, so that the sectional area decreases. The positive displacement fluid machine according to claim 1. 3. The lubricating fluid supply groove according to claim 1, wherein both the groove width and the groove depth decrease toward the end of the supply groove through which the lubricating fluid flows.
A positive displacement fluid machine as described. 4. The positive displacement fluid machine according to claim 2, wherein the lubricating fluid supply groove has an end portion of the supply groove through which the lubricating fluid flows closed in a bearing portion. 5. The method according to claim 1, wherein the length of the sealing portion is 1 to 2 of the bearing width.
5. The positive displacement fluid machine according to claim 4, wherein the range is 0%. 6. A mechanism for compressing or transferring a fluid or extracting mechanical energy from a working fluid, a shaft for driving the mechanism or extracting mechanical energy, and rotatably supporting the shaft. In a displacement type fluid machine including a bearing, a lubricating fluid supply hole configured to supply a lubricating fluid to a bearing unit including the shaft and the bearing, and a storage chamber storing the lubricating fluid, the bearing unit communicates with the storage chamber. A lubricating fluid supply groove communicating with the lubricating fluid supply hole is provided, and an end of the lubricating fluid flowing groove is sealed in the bearing portion, and the length of the sealed portion is set within a range of 1 to 20% of the bearing width. A positive displacement fluid machine. 7. The positive displacement fluid machine according to claim 1, wherein the lubricating fluid supply groove is provided on a surface on which no load is applied among the outer shaft surface and the inner bearing surface.