JPS6324121B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing device for a scroll fluid machine used in a compressor, an expander, a liquid pump, or the like.

A scroll fluid machine consists of an orbiting scroll that has an end plate and a wrap that stands upright on the end plate and is formed by an involute or a curve close to an involute, and a fixed scroll that has a configuration in which a discharge port is added to the orbiting scroll, with the wraps facing inward. interlocking with each other and placing it inside a housing having a suction port, interposing an Oldham ring between the orbiting scroll and the housing or the fixed scroll to prevent rotation of the orbiting scroll,
A crankshaft is engaged with the orbiting scroll, the orbiting scroll is rotated by the crankshaft so as not to appear to rotate on its own axis, and a pump is applied to the fluid in the sealed space formed by both scrolls, or pressurized fluid is supplied from the discharge port. The compressor supplies and expands the pressure fluid to generate rotational power to the crankshaft. A scroll fluid machine of this type is disclosed, for example, in US Pat. No. 3,884,599.

The crankshaft in this scroll fluid machine is usually arranged vertically, and the shaft portion is supported by two upper and lower sliding bearings, and the crank portion is engaged with a sliding bearing provided on the orbiting scroll. Therefore, the crankshaft is able to move a small amount in the radial direction within the gap that exists between the crankshaft and the opposing sliding bearing. On the other hand, in this scroll fluid machine, fluid pressure within a sealed space formed by both scrolls acts in the radial direction of the crank portion of the crankshaft through the orbiting scroll. For this reason, the crankshaft is tilted between the upper sliding bearing and the lower sliding bearing that support the shaft portion, and is strongly pressed against each bearing in a one-sided state. As a result, each bearing was unable to obtain an oil film reaction force capable of responding to the load due to this fluid pressure, and each bearing was subject to wear or seizure.

The present invention has been made based on the above-mentioned matters, and an object thereof is to provide a bearing device for a scroll fluid machine that can always generate an appropriate oil film pressure on the bearing and prevent wear and seizure of the bearing. do.

The present invention is characterized in that a fixed scroll and an orbiting scroll are combined, a crank portion connecting the orbiting scroll and a shaft is supported by a sliding bearing, and the shaft is provided in a frame.
and a scroll fluid machine supported by a first sliding bearing close to the orbiting scroll and a second sliding bearing farther from the orbiting scroll, the bearing clearance between the first sliding bearing and the second sliding bearing; By setting the ratio between the distance between the sliding bearings and the distance between the sliding bearings to an appropriate value, an appropriate oil film pressure distribution is always generated in the bearings, and seizure or wear of the bearings is prevented.

Embodiments of the present invention will be described below with reference to the drawings.

In the embodiments described below, a case will be described in which a scroll fluid machine is used as a compressor.

FIGS. 1 to 3 show a scroll fluid machine equipped with an example of the oil supply device of the present invention. In FIG. 1, 1 is a chamber, 2 is a fixed scroll, and 3 is a chamber.
is an orbiting scroll. The fixed scroll 2 and the orbiting scroll 3 each have disk-shaped end plates 4 and 5 and spiral wraps 6 and 7 formed upright thereon.
and are interlocked with their laps 6 and 7 facing inward. A sliding bearing 8 is mounted on the lower surface of the orbiting scroll 3. This slide bearing 8 has a shaft portion 9 of a crankshaft 9.
A crank portion 9b that is eccentric with respect to the center of a is engaged. A shaft portion 9a of the crankshaft 9 is supported by an upper sliding bearing 11 and a lower sliding bearing 12 mounted on a frame 10. The crankshaft 9 is rotated by an electric motor 13. Due to this rotation of the crankshaft 9, the orbiting scroll 3 is moved to the Oldham ring 14.
Although it makes a turning movement by the Oldham key 15 and the Oldham key 15, the apparent rotation is prevented. Due to this movement, the gas sucked in from the suction pipe 16 is compressed inside the orbiting scroll 3 and the fixed scroll 2, and is discharged from the discharge port 17 into the chamber 1 and discharged from the discharge pipe 18. Both scrolls 2,
Due to the compression action of the fluid confined by 3,
The load acting on the shaft portion 9a through the orbiting scroll 3, the slide bearing 8, and the crank portion 9b of the crankshaft 9 is received by the slide bearings 11 and 12. An eccentric oil supply passage 19 is provided in the crankshaft 9, and the eccentricity of the passage 19 increases with respect to the center of the shaft portion 9a toward the top thereof. The eccentric oil supply path 19 sucks up oil from the bottom of the chamber 1 by the action of a centrifugal pump as the crankshaft 9 rotates, and supplies the oil to each of the bearings 8, 11, and 12.

The oil supply structure for each bearing 8, 11, 12 will be explained with reference to FIGS. 2 and 3. In these figures, oil supply to the sliding bearing 8 of the orbiting scroll 3 is performed as follows. That is, the eccentric oil supply path 19
The oil at the bottom of the chamber 1 is sucked up by the centrifugal pump action of the
The upper end leads to an oil chamber 20 defined by the plain bearing 8 and the orbiting scroll 3. The oil led to the oil chamber 20 passes through an oil supply groove 21 provided in the axial direction on the outer peripheral surface of the crank portion 9b of the crankshaft 9, and lubricates the sliding bearing 8 of the orbiting scroll 3 and the crank portion 9b. The oil that lubricates the slide bearing 8 passes through an annular groove 23 provided at the connection between the crank part 9b of the crankshaft 9 and the balance weight 22 to the thrust bearing 2 integrally formed at the bottom of the slide bearing 8.
4 is then discharged into an intermediate chamber 25 defined by the frame 10 and the orbiting scroll 3.

To supply oil to the upper plain bearing 11 that supports the shaft portion 9a of the crankshaft 9, the oil sucked up by the eccentric oil supply path 19 is passed through the oil supply hole 2b which communicates with the eccentric oil supply path 19, and the shaft portion 9a. This is done by supplying oil to a groove 27 provided in the axial direction on the outer peripheral surface of the oil. The oil that lubricates this sliding bearing 11 flows through an annular groove 2 provided at the connection between the shaft portion 9a and the balance weight 22.
8 and flows into the last bearing 29 integrally formed on the upper part of the slide bearing 11, and after lubricating this, is discharged into the intermediate chamber 25. A portion of the oil lubricating the upper sliding bearing 11 is discharged from the lower end of the sliding bearing 11 into the oil drain chamber 30 defined by the shaft portion 9a, the frame 10, the sliding bearings 11, and 12. The oil is discharged into the chamber 1 through the oil drain hole 31 provided in the frame 10.

The oil discharged into the aforementioned intermediate chamber 25 passes through the pores 32 provided in the orbiting scroll 3 and is discharged to the meshing portion of both scrolls 2 and 3. Therefore, the pressure in the intermediate chamber 25 is intermediate between the discharge pressure and the suction pressure. Therefore, the upper plain bearing 11
The oil supply to the sliding bearing 8 of the orbiting scroll 3 is performed using the pressure difference between the discharge pressure and the intermediate pressure, and the eccentric oil supply path 1.
This is carried out by the centrifugal pump action of 9.

To supply oil to the lower plain bearing 12 that supports the shaft portion 9a of the crankshaft 9, the oil sucked up by the eccentric oil supply passage 19 is passed through the oil supply hole 33 which communicates with the eccentric oil supply passage 19 and the oil supply hole 33 that communicates with the eccentric oil supply passage 19. This is done by supplying the oil to the oil supply groove 34 provided in the axial direction on the outer circumferential surface of 9a. The oil that lubricates this sliding bearing 12 is
The oil is discharged into the chamber 1 from the upper end through the oil drain chamber 30 and the oil drain hole 31, and is also discharged into the chamber 1 from the lower end of the slide bearing 12.

In this example, the axial oil supply grooves 21, 27, 34 and the oil supply holes 26, 33 mentioned above are lines connecting the center S of the shaft portion 9a of the crankshaft 9 and the center C of the crank portion 9b, as shown in FIG. It is placed on the X. That is, the oil supply groove 21 has a fluid pressure P
The oil supply groove 27 is provided at a position shifted by 180 degrees with respect to the oil supply groove 21, and the oil supply groove 34 is provided at a position shifted by 180 degrees with respect to the oil supply groove 27. It is located at a different position. These oil supply grooves 21, 27, 3
The arrangement 4 is to effectively generate a bearing oil film reaction force, and to ensure that the eccentric oil supply path 19 is on the line X connecting the center S of the shaft part 9b and the center O of the crank part 9b when viewed from the upper end of the crank part 9b. This is based on the fact that the oil supply holes 26 and 33 are provided in the oil supply holes 26 and 33, and on the manufacturing aspects of the oil supply holes 26 and 33. However, the oil supply grooves 21, 27, 34 and the oil supply holes 26, 33 do not necessarily need to be arranged on the above-mentioned line X for the following reason. That is, the total pressure P of the fluid in the plurality of sealed spaces formed by the scrolls 2 and 3 acts on the crank portion 9b at a substantially right angle to the line X, as shown in FIG. It has been confirmed that the rotation moves in synchronization with the rotation of the When this fluid pressure P is decomposed into component forces perpendicular to it, it can be divided into component force P _x in the direction of line X and component force P ₁ perpendicular to line X, and these component forces P _x
The size ratio between P x and P ₁ is about P _x :P ₁ = 1:8. Therefore, the fluid pressure P can be considered to be approximately the same as the component force P ₁ perpendicular to the line X.

The crankshaft 10 is driven by the electric motor 13 into the fourth
When rotated clockwise as shown by arrow A in the figure, the orbiting scroll 3 performs an orbiting motion relative to the fixed scroll 2, internally compressing the gas sucked in from the suction pipe 16, and discharging it from the discharge pipe 18. During such a compression stroke, the pressure P ₁ of the fluid in the closed space formed by both scrolls 2 and 3 increases to the crankshaft 9 through the orbiting scroll 3 and the plain bearing 8, as shown in FIGS. 3 and 4. It acts on the crank portion 9b. Therefore, the crankshaft 9 is mounted on the upper sliding bearing 11.
and tilt within the lower bearing 12. Rare, swivel bearing 8
Among them, the crank portion 9b is tilted. If this inclination becomes large, appropriate and sufficient oil film pressure within the bearing and oil film reaction force based on this oil film pressure cannot be obtained.
There is a large uneven contact at the lower part of the swing bearing 8, the upper part of the upper sliding bearing 11, and the lower part of the lower sliding bearing, and there is a risk of seizure and wear. Therefore,
It is necessary to keep this slope within a certain range. now,
The upper end of the upper sliding bearing 11 and the lower sliding bearing 12
If the distance from the lower end of is L, and the bearing diameter clearances between the upper sliding bearing 11 and the lower sliding bearing 12 are respectively C ₁ and C ₂ , then increasing the bearing diameter clearances C ₁ and C ₂ will reduce the shaft inclination. get bigger and distance
Considering that shortening L ₁ increases C ₁ ,
By keeping the dimensions of C ₂ and L ₁ , ie (C ₁ + C ₂ )/2L, below a certain value, seizure and wear of the bearing can be prevented.

Next, the operation of the embodiment of the present invention described above will be explained.

The fluid pressure _P1 passes through the orbiting scroll 3 and the plain bearing 8 to the crank part 9 of the crankshaft 9.
It acts on b. Therefore, the crankshaft 9 is tilted between the upper sliding bearing 11 and the lower sliding bearing 12. As a result, the sliding bearing 11 is loaded with
A load P ₂ acts on the slide bearing 12, and a load P ₃ acts on the sliding bearing 12. The relationships among the positions of the oil supply grooves 21, 27, and 34, the direction of load action, and the oil film pressure distribution generated in each bearing at this time are shown in FIGS. 5 to 7, respectively.
In these figures, the fluid pressure P is expressed as its component force _P1 for convenience of explanation. As is clear from these figures, the oil supply grooves 21, 27, and 34 are always located 90 degrees clockwise with respect to the line of action of each load P ₁ , P ₂ , and P ₃ , and each load P ₁ ,P ₂ ,
P ₃ rotates and moves in synchronization with the rotation of the crankshaft 9. At this time, if (C ₁ + C ₂ )/2L is set to an appropriate value, the oil that has flowed into the bearing clearance of each bearing 8, 11, 12 through the oil supply grooves 21, 27, 34 will be As shown in the figure, each load P ₁ ,
Oil film reaction force F ₁ , F ₂ , sufficient to oppose P ₂ , P ₃ ,
Causes _F3 . As mentioned above, the positional relationship between the lines of action of the loads P ₁ , P ₂ , and P ₃ and the oil supply grooves 21 , 27 , and 34 is constant for each bearing, so the formation of oil film pressure in each bearing is approximately the same. It's the same. Therefore,
The oil film pressure distribution formed between the upper sliding bearing 11 and the shaft portion 9a shown in FIG. 6 will be explained in more detail.

The center O ₁ of the shaft portion 9a is eccentric from the center B ₁ of the sliding bearing 8 due to the load. center of these
In the line Y ₁ connecting O ₁ and B ₁ , the minimum clearance position Z _a1 of the bearing is formed on the side where the load P ₂ acts, and the maximum clearance position Z _a2 is formed on the opposite side. and,
The oil introduced from the oil supply groove 27 with a supply pressure is drawn into the bearing gap between the shaft section and the slide bearing 11 by the supply pressure and the rotation of the shaft section 9a, and is drawn out with respect to the rotation direction of the shaft section 9a. It is forced into the area of the bearing clearance, which is a narrow clearance, and a so-called wedge effect occurs. Due to the effect of this wedge action, the oil film pressure increases from the maximum clearance position Z _a2 and reaches its maximum before the minimum clearance position Z _a1 , producing an oil film pressure F ₁ that opposes the load P ₁ . After that, the oil film pressure decreases and becomes approximately an intermediate pressure at the minimum clearance position Z _a1 . In a widening gap region from the minimum clearance position Z _a1 formed along the rotational direction of the shaft portion 9a, the oil film pressure decreases from the minimum clearance position Z _a1 and becomes lower than the intermediate pressure.
Thereafter, the oil film pressure reaches the minimum value and then recovers, and becomes the supply oil pressure at the oil supply groove 27 portion. And oil supply groove 2
1 and the maximum clearance position Z _a2 , the crank part 9
Since the gap widens in the direction of rotation of b, the oil film pressure decreases and then gradually recovers, reaching approximately intermediate pressure at the maximum gap position Z _a2 .

Next, the axial oil film pressure distribution generated between the upper sliding bearing 11 and the shaft portion 9a will be explained. Shaft part 9a of crankshaft 9
is tilted within the upper and lower plain bearings 11 and 12, so the bearing clearance Z _b at the upper end of the load side of the upper plain bearing 11 is small, and conversely, the clearance Z _c at the lower end is small, as shown in Fig. 4. big. Therefore, the oil film pressure becomes an intermediate pressure at the upper end of the sliding bearing 11, and as it goes downward, the oil film pressure increases rapidly at first, reaches the maximum value, and then gradually decreases until it reaches almost the supply level at the lower end of the sliding bearing 11. It becomes hydraulic.

As mentioned above, when (C ₁ + C ₂ )/2L is set to an appropriate value, the inclination of the shaft portion 9a within the upper sliding bearing 11 and the lower sliding bearing 12, and the crank portion within the slewing bearing 8. The inclinations of bearings 8 and 1 are simultaneously set to approximately the same appropriate values.
1 and 12, oil film reaction forces F ₁ to F ₃ sufficient to support loads P ₁ to _{P 3} are simultaneously and appropriately generated on their sliding surfaces. Further, the reaction moment due to the oil film reaction forces F ₂ and F ₃ that opposes the moment due to the loads P ₁ to _{P 3} that tends to tilt the crankshaft increases, and the inclination of the shaft can be reduced. As a result, the crankshaft 9 and each bearing 8,
11, 12 is prevented, each bearing 8, 1
Wear and seizure of items 1 and 12 can be prevented at the same time. It has been confirmed that the value of (C ₁ + C ₂ )/2L that can prevent seizure and wear is 6×10 ^-4 or less.

Figures 8 and 9 show the oil film pressure generated within the bearing when the bearing diameter clearance between the upper sliding bearing 11 and the lower sliding bearing 12 increases and (C ₁ + C ₂ )/2L increases. This shows the distribution. In this case, since the inclination between the upper sliding bearing 11 and the shaft portion 9a in FIG. 8 is large, the clearance Z _c at the lower end of the upper sliding bearing 11 becomes larger than in the case of FIG. 4, and the oil film pressure reaches its maximum value. The rate of decrease in the oil film pressure after this is large, and for this reason the maximum value is also smaller than in the embodiment shown in FIG. Therefore, as shown in FIG. 9, the maximum value of the oil film pressure in the circumferential direction also becomes smaller, and the oil film pressure generated within the bearing becomes smaller overall. As a result, each bearing 8,
11 and 12, loads P ₁ to _{P 3} are applied to the sliding surfaces.
In addition, sufficient oil film reaction force is not obtained to support the oil film reaction force, and the reaction moment due to the oil film reaction forces F ₂ and F ₃ does not act sufficiently, causing uneven contact between each bearing 8, 11, 12 and crankshaft portion 9. , each bearing 8, 11,
There is a risk of wear and seizure of 12.

FIG. 10 shows an embodiment in which an example of the bearing device of the present invention is applied to another type of scroll fluid machine. In this figure, 35 is a fixed scroll, and 36 is an orbiting scroll. A sliding bearing 38 is mounted inside the upper side of the large diameter portion 37a of the crankshaft 37. The slide bearing 38 is eccentric with respect to the center of the large diameter portion 37a, and a rotating shaft 36a formed integrally with the orbiting scroll 36 is engaged with the slide bearing 38. crankshaft 3
The large diameter portion 37a of No. 7 has an upper sliding bearing 40 and a lower sliding bearing 41 mounted on the frame 39.
Supported by. Both scrolls 35,3
Due to the compression action of the fluid confined by 6,
The load acting on the crankshaft 37 through the orbiting scroll 36, the orbiting shaft 36a, and the slide bearing 38 is received by the slide bearings 40 and 41. An eccentric oil supply path 42 is provided in the crankshaft 37, and the eccentricity of the oil supply path 42 increases with respect to the center of the crankshaft 37 toward the top thereof. The sliding bearing 38 is supplied with oil through an oil chamber 43 that communicates with an eccentric oiling passage 42 and an axial oiling groove 44 that communicates with this and is provided on the inner peripheral surface of the sliding bearing, and the upper sliding bearing 40 is supplied with oil through an eccentric The lower sliding bearing 41 is supplied with oil through an eccentric oil supply passage through an oil supply hole 45 that communicates with the oil supply passage 42 and an axial oil supply groove 46 that communicates with this and is provided on the outer peripheral surface of the large diameter portion 37 of the crankshaft 37. This is done through an oil supply hole 47 communicating with the oil supply hole 42 and an axial oil supply groove 48 which communicates with the oil supply hole 47 and is provided on the outer peripheral surface of the shaft portion 37b of the crankshaft 37. Oil that lubricated the plain bearing 38 and the upper plain bearing 40
The oil that lubricates the large diameter portion 37a of the crankshaft
The thrust bearing 51 formed integrally with the upper part of the sliding bearing 40 is lubricated through an annular groove 50 provided at the connecting portion of the balance weight 49 and the balance weight 49, and is discharged into an intermediate chamber 52 defined by the frame 39 and the orbiting scroll 36. be done. A portion of the oil lubricating the slide bearing 40 flows from the lower end of the slide bearing 40 to the shaft portion 37.
b, the oil is discharged into the oil drain chamber 53 defined by the frame 39, the slide bearing 40, and the slide bearing 41, and then is discharged into the chamber through the oil drain hole 54 provided in the frame 39. Lower plain bearing 41
The lubricated shaft is discharged from the upper end of the slide bearing 41 into the chamber through the oil drain chamber 53, and is also discharged into the chamber from the lower end of the slide bearing 41.

The oil discharged into the intermediate chamber 52 mentioned above passes through the pores 55 provided in the orbiting scroll 36 and is discharged to the meshing portion of both scrolls 35 and 36. Therefore, the pressure in the intermediate chamber 52 is intermediate between the discharge pressure and the suction pressure. Therefore, the upper plain bearing 4
Oil supply to the sliding bearing 38 is performed by the differential pressure between the discharge pressure and the intermediate pressure, and by the centrifugal pump action of the eccentric oil supply path 42. Lower plain bearing 4
1 is supplied with oil by the centrifugal pump action of the eccentric oil supply path 42.

The aforementioned axial oil supply grooves 44, 46, and 48 are located at positions where the center of the plain bearing 38 is eccentric to the center of the crankshaft 37 on the line X connecting the center S of the crankshaft 37 and the center O of the plain bearing 38. It has been placed. In this way, the direction of load application and the positional relationship of each oil supply groove can be adjusted according to the fourth embodiment described above.
As in Figures to Figures 7, each oil supply groove is always at a position 90° clockwise relative to the direction of load action.
The relationship between each oil supply groove position and oil film pressure distribution is also the same.

In this embodiment, since the pivot shaft 36a is engaged with a slide bearing 38 located inside the large diameter portion 37a of the crankshaft 37, the load _P1 due to the fluid pressure acts on the upper slide bearing 40.
Therefore, the crankshaft 37 is forced to one side as shown in FIG. Upper sliding bearing 40 and large diameter portion 37a of crankshaft 37
The bearing diameter clearance between the lower sliding bearing 41 and the shaft part 37 of the crankshaft 37 is _C1 .
Assuming that the clearance with respect to b is _C2 , the diameter of the upper sliding bearing 40 is larger than that of the upper sliding bearing 41. In such cases, the clearance C ₁ is usually changed to the clearance C ₂
Become bigger. Due to the difference between the clearance C ₁ and the clearance C ₂ , the crankshaft 37 tilts between the upper and lower sliding bearings 40, 41. As this tilt increases, the upper and lower sliding bearings 40, 4
The large diameter portion 37 of the crankshaft 37 at the upper end of 1
a and the shaft portion 37b, and at the same time, the bottom end of the slide bearing 38 has a large uneven contact with the pivot shaft, creating a risk of seizure and wear. The magnitude of the inclination of _the crankshaft 37 is determined by (C ₁
−C ₂ )/2L ₁ . If this value is set to 6×10 ⁻⁴ or less as in the above-described embodiment, seizing and wear of the slide bearings 38, 40, and 41 can be prevented at the same time.

In the embodiment shown in FIGS. 10 to 12, the shaft portion 37b of the crankshaft 37 is the large diameter portion 37a.
Although the diameter is smaller, the same can be said for the same diameter. In other words, the bearing diameter clearances C ₁ and C ₂ cannot be made the same due to processing considerations. When the clearance C ₁ is larger than the clearance C ₂ , the embodiment is the same as shown in Figures 10 to 12, but when the clearance C ₁ is smaller than the clearance C ₂ , the slope is reversed, and C ₂ −C When ₁ becomes large, uneven contact occurs between the upper ends of the upper and lower sliding bearings 40 and 41 and the upper end of the sliding bearing 38. In such a case, assuming that the distance between the upper ends of the upper and lower sliding bearings 40, 41 is _L2 , the magnitude of the inclination of the crankshaft 37 is expressed as ( _C2 - _C1 )/ _2L2 .
It is necessary to set this value to 6×10 ^-4 or less.

In the case described above, the inclination of the crankshaft within the bearing becomes large. However, as the bearing diameter clearance decreases, the inclination decreases;
If the clearance becomes too small, the amount of heat generated within the bearing will increase, the bearing temperature will rise, and the viscosity of the oil will decrease, which will reduce the thickness of the oil film between the crankshaft and the bearing, resulting in metal-to-metal contact and bearing seizure. ,
Risk of wear. Therefore, the bearing clearance, that is, the size of the shaft inclination (C ₁ + C ₂ )/2L,
(C ₁ −C ₂ )/2L ₁ and (C ₂ −C ₁ )/2L ₂ need to be greater than a certain value. And we have confirmed that this value is 2×10 ^-4 .

As detailed above, according to the present invention, it is possible to prevent uneven contact of the bearing of a scroll fluid machine, thereby preventing seizure and wear of the bearing, and improving the life and reliability of the scroll fluid machine. be able to.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a scroll fluid machine equipped with an embodiment of the oil supply device of the present invention, and FIG. 2 is a longitudinal cross-section showing an enlarged portion of a crankshaft equipped with an embodiment of the oil supply device of the present invention. 3 is a plan view of the crankshaft showing the relationship between the oil supply groove and the direction of load application in the device of the present invention, and FIG. 4 is a plan view of the crankshaft of the scroll fluid machine shown in FIG. An explanatory diagram showing the relationship between the load acting direction and the bearing oil film pressure distribution in the state of rotation. Figures 5 to 7 are plan views showing the relationship between the load acting direction and the bearing oil film pressure distribution in each bearing. , 5th
The figure is a view taken from the - line of Fig. 4, Fig. 6 is a view taken from the - line of Fig. 4, Fig. 7 is a view taken from the - line of Fig. 4, and Fig. 8 shows a crankshaft with a large inclination. Fig. 9 is an explanatory diagram showing the relationship between the load action direction and the bearing oil film pressure distribution in the case of the above cases, and Fig. 9 is a view taken along the - line in Fig. 8; FIG. 10 is an enlarged vertical sectional view of a crankshaft portion when an embodiment of the bearing device of the present invention is applied to another type of scroll fluid machine, and FIG. 11 is a longitudinal sectional view showing the crankshaft portion shown in FIG. 10. FIG. 12 is an explanatory diagram showing the relationship between the direction of load action and the bearing oil film pressure distribution when the crankshaft of the scroll fluid machine shown in FIG. 10 is rotated 90 degrees counterclockwise. . 1...Chamber, 2...Fixed scroll, 3...
...Orbiting scroll, 4, 5...End plate, 6,7...
Rap, 8...Sliding bearing, 9...Crankshaft, 9a...Shaft part of crankshaft 9, 9b...Crank part of crankshaft, 1
1, 12...Sliding bearing, 19...Eccentric oil supply path,
21, 27, 34... Oil supply groove.

Claims (1)

[Claims] 1. A fixed scroll and an orbiting scroll are combined, a crank part connecting the orbiting scroll and a shaft is supported by a sliding bearing, and the shaft is mounted on a frame and close to the orbiting scroll side. In a scroll fluid machine supported by a first plain bearing and a second plain bearing on a side farther from the orbiting scroll, the first bearing diameter clearance with the shaft in the first plain bearing and the second plain bearing in the second plain bearing. 2nd with shaft
A bearing for a scroll fluid machine, characterized in that a bearing diameter clearance and a distance between the first and second sliding bearings are set in a positional relationship that prevents uneven contact with the bearing due to shaft tilting. Device. 2 In a crank unit that combines a shaft body provided eccentrically at the end of the shaft and a sliding bearing provided in the boss portion of an orbiting scroll, the first bearing diameter clearance C ₁ and the second bearing diameter clearance C ₂ and
The distance L between the end of the first sliding bearing on the orbiting scroll side and the end of the second sliding bearing on the anti-orbiting scroll side is 2×10 ^-4 <C ₁ +C ₂ /2L <6×10 ^-4 2. A bearing device for a scroll fluid machine according to claim 1, wherein the bearing device is set in a relationship with the bearing device of claim 1. 3 In a crank unit that combines a shaft body provided eccentrically to the boss portion of an orbiting scroll and a sliding bearing provided at the end of the shaft, the first bearing diameter clearance C ₁ is equal to the second bearing diameter clearance C ₂ , the distance L between these clearances C ₁ and C ₂ and the orbiting scroll side ends of the first and second plain bearings is 2×10 ^-4 <C ₁ −C ₂ /2L _1. A bearing device for a scroll fluid machine according to claim 1, characterized in that the relationship is set to 1<6×10 ⁻⁴ . 4 In a crank unit that combines a shaft body provided eccentrically to the boss portion of an orbiting scroll and a sliding bearing provided at the end of the shaft, the first bearing diameter clearance C ₁ is equal to the second bearing diameter clearance C ₁ , the distance L ₂ between these clearances C ₁ and C ₂ and the anti-orbiting scroll side ends of the first and second plain bearings is 2×10 ^-4 <C ₂ −C ₁ 2. The bearing device for a scroll fluid machine according to claim 1, wherein the bearing device is set to the relationship: /2L ₂ <6×10 ⁻⁴ .