JPS6040701A - Scroll hydraulic machine - Google Patents

Abstract

PURPOSE:To reduce mechanical loss by specifying the crank radius of a crank shaft connected to a rotary scroll to retain a required gap in the radial direction between the both laps of a fixed scroll and said rotary scroll, and preventing the contact between the both laps. CONSTITUTION:In a scroll hydraulic machine, a fixed scroll 1 has a spiral lap 1b, a rotary scroll 2 has a spiral lap 2b which is engaged with the lap 1b, and the rotary scroll 2 is rotated by means of a motor and through a crank shaft 6. This crank shaft 6 consists of a main shaft 6a connected to the rotor of the motor, and an eccentric shaft 6b constructed in an integrated form with the main shaft 6a. The rotary scroll 2 is connected to the eccentric shaft 6b of the crank shaft 6 through a bearing 17c. In this case, the value of the crank radius epsilons of the crank shaft 6 is set smaller than the value of the rotating radius which is determined by the lap by a certain quantity delta, which is set at a greater value than the half of the diametral clearance of the bearing 17c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a scroll fluid machine used as a compressor, vacuum pump, liquid pump, or expander.

[Background of the invention]

A scroll fluid machine is a scroll member in which a thinly wound wrap is provided upright on an end plate, and a pair of scroll members are engaged with each other with the wraps facing each other, so that one scroll member rotates relative to the other without rotating on its own axis. It is used for compressing gases, transporting liquids, or expanding gases. In such a device, Japanese Patent Laid-Open No. 53-92915 discloses that a small radial gap is provided between the side wall surfaces of the wraps of a pair of scroll members to minimize wear caused by sliding of the wraps. There is. However, although this conventional method can provide a gap between the side wall surfaces of both wraps, it does not necessarily provide a gap of a size suitable for the device. This is because the gap between the bearings disposed between the orbiting scroll member and the drive shaft is not considered at all, so the crank radius is substantially increased by the distance corresponding to the size of the bearing gap. This is because during operation, there may be no gap between the wraps, or the gap between the side wall surfaces of the wraps may become smaller than the gap planned in advance. Further, since the bearing gap of the bearing used at that location is not necessarily constant, the gap between the side wall surfaces of the wraps is not constant after all.

[Purpose of the invention]

An object of the present invention is to provide a scroll fluid device in which the turning radius of the crankshaft portion has an easily adapted value.

[Summary of the invention]

The main feature of the present invention is that the crank radius of the crankshaft (the distance from the center of the shank to the center of the center of the crankshaft) which determines the gap between the side wall surfaces of the wraps in the pair of scroll members is used in this device. This is because it was determined based on the bearing clearance provided by the manufacturer. Specifically, the crank radius εl+ of the crankshaft is made smaller than the value εW of the turning radius ε determined by the scroll member by a length corresponding to half the diameter gap C of the bearing, and This is to prevent the substantial turning radius of the crankshaft from becoming larger than the turning radius determined by the scroll. (1) The orbiting scroll must be able to move within the bearing clearance relative to the crankshaft, and during operation, the orbiting scroll is subject to centrifugal force and load force (opposite to the rotation direction). (acting in the direction) acts.

The centrifugal force acts to maximize the effective turning radius of the crankshaft within the range of the bearing clearance, and the load force acts to make the effective turning radius of the crankshaft approach the crank radius εS of the crankshaft. to work.

When the device is in operation, both centrifugal force and load force act on the orbiting scroll member, so the effective turning radius ε of the crankshaft during operation is determined by the crank radius εB of the crankshaft and the crank radius ε8 of the bearing. The length εs is the sum of the length equivalent to about half the diameter gap C/2
+C/2). If this is expressed as an equation, it will be as shown in equation (2).

ε8≦Square εs1C/2 ・・・・・・・・・(2) On the other hand, as mentioned above, the crank radius of the crankshaft ε8
is formed as εS=εwC/2, so by substituting this relationship into equation (2), εw−C/2≦εW...
......(3).

Therefore, the substantial turning radius ε of the crankshaft during operation is equal to the turning radius εW determined from the scroll υ
The gap always becomes smaller, and a minute gap is inevitably formed between the wrap side wall surfaces. In this way, the turning radius ε. If the length to reduce the diameter of the bearing is set to about half the diameter clearance C of the bearing, during operation, the gap between the laps can be reduced from a maximum of about half the bearing clearance C to a minimum due to the action of the load force acting on the orbiting scroll member. It can be operated within a range that avoids contact with the lap.

In the present invention, the turning radius determined from the scroll wrap means the turning radius when the orbiting scroll rotates without rotating on its own axis, with the side wall surfaces of both wraps lightly touching each other. This is a turning radius that takes into consideration factors such as the machining accuracy of the side surface of the lap, and the surface roughness.

Of course, this turning radius can be determined from the actual measurement results, but it can also be calculated from the theoretical turning radius, machining accuracy, and surface roughness.

Also, the set gap means the gap given in advance between the side walls of the wraps of both scrolls and the dirt floor, and the size of the set gap is arbitrary; however, the amount of thermal expansion and deformation of the crankshaft,
It is determined by considering the amount of inclination, etc.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 11.

FIG. 1, FIG. 2, and FIG. 3 are explanatory diagrams of a first embodiment in which the present invention is applied to a compressor.

This scroll compressor includes a casing 3, a frame 4 fixed to the inner wall surface of the casing 3, and a frame 4 fixed to the inner wall surface of the casing 3.
a fixed scroll 1 fixed to the frame 4, an orbiting scroll 2 disposed between the fixed scroll 1 and the frame 4, a crankshaft 6 supported by the frame 4 via bearings, a motor 5 attached to the crankshaft 6, and a frame. 4
and the orbiting scroll 2.
It is equipped with

The casing 3 has a body 3a, an upper cover 3b, and a lower cover 3C formed in a sealed shape, and a compressed gas discharge chamber 8 is formed in the upper part of the inside of the casing 3.
A compression nozzle discharge chamber 9 is formed in the middle part, and a lubricating oil chamber 10 is formed in the lower part.

The production fluid is sucked in through the suction pipe 11, compressed in the compression chamber (2), discharged from the discharge hole 12 into the discharge chamber 8, and discharged through the frame cutout 13 into the discharge chamber 9. Here, the lubricating oil is separated and settled in the lubricating oil chamber 10, and only the gas is discharged from the casing 3 through the discharge pipe 14.

The fixed scroll 1 consists of an end plate 1a, a thinly wound wrap 1b standing upright on the end plate 1a, and an annular peripheral edge IC. The end plate 1a is provided with a discharge hole 12 for discharging the regular gas from the center of the compression chamber V, and the peripheral portion 1C is provided with a suction hole 15 for the gas to be compressed. It is being

The orbiting scroll 2 consists of an end plate 2a, a wrap 2b standing upright on the end plate 2a, and a bearing part 2C.
It is installed in a housing chamber formed at the top of the.

A back pressure chamber 7 is formed between the end plate 2a and the frame 4, and the end plate 2a is provided with back pressure holes 15a and 16b for guiding gas pressure from the middle part of the compression chamber V to the back pressure chamber 7. ing.

The crankshaft 6 includes a main shaft 5a connected to the rotor 5a of the motor 5, and an eccentric shaft 6b integrally formed at the upper end of the main shaft 5a. The axial center Op of the eccentric shaft 6b is provided at a position offset by a distance ε8 from the axial center O11 of the main shaft 6a. The main shaft 6a is supported by the frame 4 by two bearings 17a and 17b attached to the frame 4.

The orbiting scroll 2 is attached to the eccentric shaft 6b via a bearing portion 17C.
are connected, the orbiting scroll 2fc and the fixed scroll 1
It is designed so that it can be rotated at rotation 9 of center 01. A balance weight 6C is integrally formed on the crankshaft 6, and a counterweight 18 is installed at the lower end of the motor rotor 5a to balance the centrifugal force acting on the orbiting scroll. The orbiting scroll is
Mass balance is maintained so that the center of gravity is located at the center of the lap base circle, and this center coincides with the axis of the bearing portion 2c.

The Oldham ring 19, which is a member that prevents rotation of the orbiting scroll, is attached to the back surface of the end plate 2a of the orbiting scroll 2 and the frame 4.
is established between. The Oldham ring 19 is similar to a well-known modification of the Oldham joint (e.g. French patent 1248634), and has a ring-like shape, with a surface facing the end plate 2a and a surface facing the frame 4 having a ring shape. has a straight groove (not shown). The groove provided on the surface facing the frame 4 is orthogonal to the groove provided on the surface facing the end plate 2a. Oldham keys 20 (20a, 20b) are installed in the groove provided on the surface facing the frame 4.
Oldham keys 21 (21a, 21b) are fitted and fixed in grooves provided on the surface facing the end plate 2a (see FIG. 3). The Oldham ring 19 reciprocates along these Oldham keys,
Although it prevents the orbiting scroll 2 from rotating, it does not have a restraining force on the movement of the orbiting scroll 2 in the radial direction.

In such a configuration, the present invention provides the crankshaft 6
on the eccentric shaft 6b and bearing 17c. crankshaft 6
The crank radius (the amount of eccentricity from the main axis of the eccentric shaft) εS becomes smaller than the turning radius εW determined by the wrap,
The reduction amount (εW-εS) is the diameter clearance C of the bearing 17c! and is less than 6-6 of the turning radius εW determined from the laps lb and 2b. That is, bearing 17
If the inner diameter of the bushing 17c' press-fitted into C is equal to the outer diameter of the Ds1 eccentric shaft 6b, then the bearing clearance is C1=DI
] I) a, reduction amount of crank radius a-(tw-
C8 is 2 (D s Da) (g, W-εskuo, o6xεW. This configuration has the following effects.

As shown in FIG. 4, when centrifugal force Fc acts on the orbiting scroll 2, the orbiting scroll moves in the eccentric direction of the eccentric shaft 6b of the crankshaft 6 because the orbiting scroll itself does not have a balance mechanism to counter the centrifugal force. . Therefore, the eccentric shaft 6
As the orbiting scroll moves in the radial direction, as long as the clearance of the bearing 17c in b allows, the substantial orbiting radius ε1 becomes large and the clearance δ on the wrap side becomes small. However, RiD
d) (Since δW - ε8 is small, there is no radial contact in the lap, which has the effect of providing a highly reliable fluid machine with low mechanical loss. Also, the crank radius The smaller the reduction amount δ = (εW - εS) within the above conditions, the smaller the gap between the laps and the smaller the fluid loss, so a rank shaft is better, but if high dimensional accuracy is required, mass production processing is required. Therefore, we considered fluid loss and machining precision K that can be measured in mass production machining.

By using a crankshaft with a crank radius reduction (εW - εS) in the range of εW - εs (0.06XεW), the mechanical loss, This has the effect of providing a scroll fluid machine that has low fluid loss and is easy to process and assemble.

If the wrap wall is lubricated with oil or a conformable soft material is formed on the wrap surface, the amount of decrease in crank radius (εW - εB) will be reduced even by the bearing bushing 17.
The relationship between c' and the eccentric shaft 6b is such that when the fluid force is small, such as during startup, the centrifugal force Fc acting on the orbiting scroll 2 causes a radial gap between the laps δ and C1 as shown in FIG.
is decided.

However, as the gas is compressed, the fluid force increases and as shown in FIG. The radial clearance δ between the two increases. The orbiting radius ε2 of the orbiting scroll 2 when fluid force is applied is as follows: DI+=Bearing force of the eccentric shaft Inner diameter Dd=Outer diameter of the eccentric shaft ε8 Eccentricity of the two eccentric shafts Fc: Centrifugal force F acting on the orbiting scroll : Tangential gas force acting on the orbiting scroll Fr : Radial gas force acting on the orbiting scroll: Reaction force from the eccentric shaft acting on the orbiting scroll is 1 or less. Therefore, during movement, half-turning,
Radial contact of the laps no longer occurs.

In addition, if there is a gap C2 between the main shaft bearings 17a and 17b, the fluid force F acting on the orbiting scroll as shown in FIG.
Since the main shaft 6a is rotated about 1 in the direction of the resultant force of t and F, the orbiting scroll 2 is moved somewhat in the direction of the main shaft center 03 by being dragged by it. Then, the orbiting motion radius ε2 of the orbiting scroll becomes even smaller, and the radial clearance δ7 of the lamp becomes smaller.
increases.

At this time, if the centrifugal force Fc acting on the orbiting scroll 2 is accurately balanced by the balance weight 6C and the counterweight 18, the crankshaft 6 will not be tilted by the centrifugal force. When there is a gap between the main shaft bearings 17a and 17b, the orbiting radius ε2 of the orbiting scroll is (see Fig. 8): tl: Main shaft bearing length 172: Distance from the main shaft bearing to the center of the eccentric shaft C2: Bearing Diameter Clearance of Main Shaft Another embodiment of the present invention is shown in FIGS. 9 and 10.

This is a compressor suitable for compressing dry gas, and the bearing of the g-moving part uses a υ bearing with sealed rollers filled with grease, and an anti-thrust bearing that uses a solid lubricant, and does not require forced oil lubrication. not going. As the turning drive means, one driving crankshaft and one or more crank pins for preventing rotation are used. The bearing 17a of the main shaft 6a is a ball bearing, which is filled with grease and has oil seals 22a and 2.
2b prevents grease from leaking. Main shaft bearing 17
b is a sealed ball bearing. Bearing 17C of eccentric shaft 6b
is a sealed needle roller bearing.

A thrust bearing 23 made of solid lubricant is installed between the back surface of the orbiting scroll 2 and the frame 4, and receives the axial gas force acting on the orbiting scroll 2 to stably support the orbiting scroll. The orbiting scroll 2 and the fixed scroll 1 have a crank pin 24 (24.
i, 24j, 24k) are provided and coupled. These crank pins function to prevent rotation of the orbiting scroll 2 and maintain the phase relationship, and are a substitute for the Oldham ring 19 shown in FIGS. 1 and 3 of the embodiment. In this embodiment, three crank pins 24 are installed as shown in FIG. 10, but if there are eleven or more crank pins 24, the function will be fulfilled. The crank pin 24 has an auxiliary shaft 24a fitted into a bearing 17d provided on the fixed scroll 1, and an auxiliary eccentric shaft 24 fitted into a bearing 17e provided on the orbiting scroll 2.
It consists of b. The amount of eccentricity between the auxiliary shaft 24a and the auxiliary eccentric shaft 24b is substantially the same in the three rank bins, and is also the same as the crank radius ε8 of the crankshaft.

Sealed needle roller bearings are used for each of the crank pin bearings 17d and 17e. Roller bearing] The radial clearance is specified by ISO or JIS, and in addition to the normal clearance, you can select one with a small clearance or one with a wide clearance. The bearing diameter clearance of the auxiliary shaft 24a of the crank pin is 03, and the bearing diameter clearance of the auxiliary eccentric shaft 24b kc<,
The bearing diameter clearance of the eccentric shaft 6b of the crankshaft 6 is C
Let it be I. In the embodiment, C1 is C3+04. With this setting, the centrifugal force Pc acting on the orbiting scroll 2 is not transmitted to the crank pin 24. Furthermore, the crank radius εB of the crankshaft 6 is smaller than the turning radius εW determined by the wrap, and the amount of decrease thereof (ε
W-εS), the amount of radial movement of the orbiting scroll 2 is limited by the bearing clearance CI of the eccentric shaft of the crankshaft, and a radial clearance δ always occurs in the lap, so that no contact occurs.

Further, by setting CI≧Cs+C4, a part or most of the centrifugal force of the orbiting scroll can be transmitted to the crankshaft/24. In this case, the crank radius εS of the crankshaft 6 must be tw-gg(-(C3+04)) for the force to be exerted.By doing this, the amount of radial movement of the orbiting scroll 20 is
is limited to the sum of the bearing clearances (C3+04), and
There is always a radial gap in the wrap, which has the effect of preventing contact.

Another embodiment of the invention is shown in FIG.

This is an example in which the above-mentioned turning drive means (two or more driving crankshafts) are used. Since the drive shaft also serves to prevent the orbiting scroll from rotating, no other rotation preventing member is required. The fixed scroll 1 includes an end plate 1a, a wrap 1b standing upright thereon, an annular peripheral edge 1c, another plate 1a', a wrap lb' standing upright thereon, and an annular edge 1c. It consists of /. The wrap 1b and the wrap 7'lb' are assembled so as to face each other, and are bolted together at the annular peripheral portions 1c and 1c/. The end plates 1j, a are provided with a discharge hole 12 for discharging compressed gas from the center of the compression chamber 1, and an intake hole 15 for the gas to be compressed.

The orbiting scroll 2 consists of an end plate 2a and wraps 2b and 2b' standing upright on both sides of the end plate 2a, and is incorporated into the fixed scroll 1. Lap 1b and lap 2b
There is a compression chamber Vt (Vtr, Vt2"Vt1.
Vtz...) is formed, and wrap lb' and lug 2b
', there are compression chambers Vb (Vb I, Vb 2 ,
...Vbx', Vbz'・) 7>" is formed.

The end plate 2a has a discharge gas passage hole 12' in the center for moving the compressed gas from the compression chamber Vb to V+, and a suction hole 12' in the periphery for distributing the gas to be compressed to the compression chambers MV t and Vb. A gas passage hole 15' is provided. Since the axial gas forces in the compression chambers Vb and Vf are equal, the resultant axial force acting on the orbiting scroll 2 is zero, and no thrust bearing is required to receive it.

A lance shaft 27 is rotatably coupled to the periphery of the end plate 2a of the orbiting scroll via a bearing 28b. It is sufficient if there are two or more crankshafts 28. In this embodiment, three crankshafts 271, 27J127k are arranged equally on the circumference, as in FIG. 12.

The crankshaft 27 includes a first shaft 28a1 and an eccentric shaft 28b.
1 and a second shaft 28C. The first shaft 28a and the second shaft 28b are concentric and have the same diameter (they may have different diameters).

The eccentric shaft 27b has a first shaft 27a1 and a second shaft 27b.
It is eccentric by a distance εB. The first shaft 27a is coupled to the fixed scroll 1 via a bearing 28a provided on the annular peripheral portion IC of the fixed scroll 1. The second shaft 27C has a bearing 28 (1, 28
It is coupled to the fixed scroll 1 via d.

The three crankshafts z71.27j and 21 are combined so that the eccentric directions of their eccentric shafts are the same.

Auxiliary gears 29 (29i, 29j, 29k) are fixed to the end of the second shaft 27C of the crankshaft.

V balancer 30 (30i, 30j, 3
0k) is provided to balance the centrifugal force acting on the orbiting scroll 2.

A main gear 32 is fixed to the end of the main shaft 31 and is meshed with the auxiliary gears 30 (30i, 30j, 30k). The main shaft 31 has a bearing 17a.

The main shaft 4 is coupled to the frame 4 via the shaft 17b, the shaft end protrudes outside the frame 4, and is coupled to an external drive source. Furthermore, where the shaft end of the main shaft 4 projects outside the frame 4, a pool means is provided. A mechanical seal 33 is provided to prevent leakage of gas and lubricating oil inside the frame 4.

The bearings, gears, and mechanical coolant are forcibly lubricated with lubricating oil, and the oil is circulated by an external oil circulation pump 34.

In the scroll compressor having such a configuration, the relationship between the bearing diameter clearance C3 between the eccentric shaft 25b of the crankshaft 25 and the bearing 26b, and the turning radius εW determined from the eccentricity εB of the eccentric shaft 25b and the wrap is -C5< εW-68. For this reason, wrap 2b of the orbiting scroll
, 2b' and a fixed scroll wrap lb.

lb' does not contact in the radial direction, mechanical loss is small,
This has the effect of providing a highly reliable scroll fluid machine.

〔Effect of the invention〕

As described above, according to the embodiments of the present invention, at startup, etc.
Even if centrifugal force is the dominant force acting on the orbiting scroll, there is a radial gap between the wraps and they do not contact each other, resulting in low mechanical loss and reliability with no increase in fluid leakage loss due to wear. This has the effect of providing a scroll fluid machine with high performance.

Further, according to the present invention, there is an effect that the radial gap between the lap side surfaces of the scroll and the earth can be made to a size suitable for the device.

[Brief explanation of the drawing]

/---・゛ Figure 11 is a sectional view of another embodiment of the present invention. 1... Orbiting scroll, 2... Fixed scroll, 1
a. 2a... End plate, lb, 2b... Wrap, 3... Casing, 4... Frame, 5... Motor, 5a...
...Motor rotor, 6...Crankshaft, 6a.
...Main shaft, 6b...-Eccentric shaft, 6C...Balance weight, 7...Back pressure chamber, 8...Discharge chamber, 9...Discharge chamber, 10...Lubricating oil chamber, 11...・Suction pipe, 12
...Discharge hole, 13...Frame notch, 14...
Discharge pipe, 15... Suction hole, 16a. 16 b-...Back pressure hole, 17 a+ l 7 b +
17 c. 17d, 17e...Bearing, 18...Counterweight, 19...Oldham ring, 20.21...Orgum key-122a, 22b...Oil seal, 23.
... Thrust bearing, 24... Crank pin, 24a.
... Auxiliary shaft, 24b ... Auxiliary eccentric shaft, 25 ... Bearing mounting part, 26 ... Fixing bolt, 27 ... Crankshaft, 27a ... Painter's shaft, 27b ... Eccentric shaft, 2
7C...Second axis, 28a, 28b, 28c, 28d-
-Bearing, 29 (291, 29j, 29k)... Auxiliary gear, 30 (30i, 30j, 30k)... Balancer, 31... Main n, 32... Main gear, 33... Mechanical Seal, 34...Oil circulation pump. 1st Mouth MZ Figure 3 Leap ¥J4 [2] Bowl 5th Eye 5th Figure 6 Sr- Sword 7 Figure 9 Mouth χ 10 Ro

Claims (1)

[Claims] 1. An end plate and a fixed scroll and an orbiting scroll formed on the end plate and having a spiral wrap having a thickness and height, which are engaged with each other with the wraps facing each other, One or more crankshafts are engaged with the orbiting scroll via bearings, and at least one of the crankshafts is engaged with the orbiting scroll through bearings.
In a system in which power is exchanged between the scroll and the orbiting scroll, the crankshaft includes a shaft portion rotatably supported on the stationary side and an eccentric portion formed on the shaft portion. The crank radius expressed as the distance from the center to the center of the eccentric portion should be a predetermined amount δ smaller than the turning radius determined by the wraps of both scrolls, and the predetermined amount δ should be less than half the diameter gap of the bearing. A scroll fluid machine characterized by having a large value. 2. The scroll fluid machine according to claim 1, wherein the predetermined amount δ has a value approximately half the diameter gap of the bearing. 3. The scroll fluid machine according to claim 1 or 2, wherein the eccentric portion formed in the main shaft portion is an eccentric shaft attached parallel to the main shaft portion. 4.% Permissible Claims In claim 1 or 2, the eccentric portion formed in the main shaft portion is a circular hole extending in the axial direction parallel to the main shaft portion, and the orbiting scroll is inserted into this circular hole via a bearing. Scroll fluid machine with engaging details mounted on. 5.4 A fixed scroll and an orbiting scroll formed on the plate and this end plate, and having a spiral wrap f: having a thickness and height, are rotated by a fixed scroll and an orbiting scroll with ramps facing each other, In a scroll in which one or more crankshafts are engaged with the scroll as bearings, and power is exchanged between at least one of the crankshafts and the orbiting scroll, the crankshaft is rotatably supported on the stationary side. The crank radius, which is represented by the distance from the center of rotation of the shaft to the eccentric part, is equal to the radius of gyration determined by the wraps of both scrolls. A scroll fluid machine characterized in that the predetermined amount δ is equal to the sum of a half value of the diameter gap of the bearing and a value of the set gap.