JPH08165993A - Scroll type fluid device - Google Patents

Abstract

PURPOSE: To improve machine efficiency through improvement of constitution to balance a rotation system and to improve reliability through ensurance of oil return, in a shaft-through type double-tooth scroll fluid device. CONSTITUTION: In a shaft-through type double-tooth scroll fluid device wherein a driven mechanism 4 is arranged at the inner upper part of a casing 2 and a scroll mechanism 3 is provided at the lower part thereof, balance weights 20a and 20b are arranged on upper and lower sides, respectively, of the scroll mechanism 3 of a crank shaft 8 extending from the drive mechanism 4 to the scroll mechanism 3. The lower end of the crank shaft 8 is supported on the under surface of a lower fixed scroll 11 and a shaft support member 21 to form a high pressure introduction space B between the lower fixed scroll 11 and the shaft support member is provided. Through-holes 10e and 11e through which the high pressure introduction space B and a space A on the discharge side are intercommunicated are formed in scrolls 10 and 11, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid device, and more particularly to improvement of a structure for balancing a rotary system.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication (Kokai) No. 3-23720.
A scroll type fluid device as disclosed in Japanese Patent Publication No. 2 is known. The structure of this type of scroll type fluid device will be described with reference to FIG. 4. In the casing (a), the motor part (b) is arranged in the lower part, and the compression mechanism part (c) is arranged in the upper part. The crankshaft (e) connected to the rotor (d) of (1) extends into the compression mechanism (c).

In the compression mechanism section (c), a wrap (f2) is erected on the front surface of an end plate (f1), and a pair of fixed scrolls (f), (f) arranged such that the front surfaces face each other. f) and the fixed scrolls (f), (f), and are fitted on both sides of the end plate (g1) with the fixed scrolls (f), (f) wraps (f2), (f2). The orbiting scroll (g) is provided with wraps (g2) and (g2) forming the working chambers (h) and (h). Also, through holes (f3), (f3), (g) are provided in the center of each scroll (f), (f), (g).
3) are respectively formed in the crankshaft (e) so that the eccentric part (e1) is located in the through hole (g3) of the orbiting scroll (g). , (g3). Lubricating oil supplied to the sliding parts of the crankshaft (e) and the orbiting scroll (g) is stored at the bottom of the casing (a).

When the apparatus is driven, the motor section (b)
The crankshaft (e) rotates with the driving of the eccentric part (e1), and the eccentric rotation of the eccentric part (e1) causes the orbiting scroll (g) to orbit with respect to the fixed scrolls (f) and (f). ), (h) are contracted to compress the fluid.

When the crankshaft (e) rotates, the eccentric part (e
In order to cancel the centrifugal force generated due to the eccentric rotation motion of 1), a balance weight (i) is provided at the lower position of the compression mechanism part (c) on the crankshaft (e), and
A counterweight (j) is provided at the lower end of the crankshaft (e) in order to cancel the moment generated in the crankshaft (e) about the compression mechanism (c). That is, these weights (i) and (j) were both arranged under the compression mechanism section (c) and sandwiching the motor section (b).

[0006]

By the way, in the above-mentioned structure, since the distance between the counterweight (j) and the compression mechanism portion (c) is relatively large, the rotating system is sufficiently balanced. It was difficult, and in order to obtain this balance, the counterweight (j) had to be large. Therefore, when the device is driven, the large counterweight (j) rotates in the casing (a), which agitates the fluid in the casing (a) to increase the agitation loss and increase the compression efficiency. It was a factor that hindered the improvement of.

Since the counterweight (j) is provided at the lower end of the crankshaft (e), the casing
It may be immersed in the lubricating oil stored at the bottom of (a).
This results in a great resistance to the rotation of the device, and the mechanical efficiency of the device is significantly reduced.

Incidentally, these problems are not limited to the so-called double-toothed scroll type fluid device in which the orbiting scroll is provided between the pair of fixed scrolls as described above, and one fixed scroll and one orbiting scroll are provided. The same occurs in a so-called single-tooth scroll fluid device.

The present invention has been made in view of this point, and an object of the present invention is to improve the compression efficiency and the mechanical efficiency by improving the structure for balancing the rotating system in a scroll type fluid device. To do.

[0010]

In order to achieve the above object, the present invention eliminates the counterweight by setting the disposition position of the balance weight on both sides of the compression mechanism in the scroll type fluid device. In addition, each balance weight has been made smaller.

Specifically, as shown in FIG. 1, the invention according to claim 1 has a spiral wrap (10) on the end plates (10a, 11a), (12a).
b, 11b), (12b, 12c) are erected, and each lap (10b, 11b), (12
b, 12c) mesh with each other to form working chambers (13), (14), and at least a pair of scrolls (10, 11), (12) arranged for relative swivel motion. Compression mechanism (3)
An eccentric part (8b) is formed in part so that the pair of scrolls (10, 11) and (12) perform a relative orbital motion.
A drive mechanism (4) having a drive shaft (8) in which the eccentric part (8b) is linked to a compression mechanism (3) is housed in a casing (2),
With the eccentric rotation of the eccentric part (8b) due to the rotation of the drive shaft (8), the pair of scrolls (10, 11) and (12) perform a relative orbital motion, and the fluid is transferred to the working chamber (13), It is premised on a scroll type fluid device in which the internal volumes of the working chambers (13) and (14) are contracted and compressed after being introduced into (14). Then, the drive shaft (8) is penetrated through the compression mechanism (3), and one end of the drive shaft (8) opposite to the side where the drive mechanism (4) is arranged is projected from the compression mechanism (3). Let Also, the drive shaft (8)
In addition, balance weights (20a), (20b) for canceling the centrifugal force generated by the eccentric rotation of the eccentric part (8b) are attached to the drive shaft.
It is provided on both sides of the compression mechanism (3) in the extension direction of (8).

According to a second aspect of the present invention, in the scroll type fluid device according to the first aspect, each balance weight is provided.
(20a) and (20b) are arranged in positions opposite to the eccentric direction of the eccentric part (8b) of the drive shaft (8) and at positions equidistant from the eccentric part (8b), and It is configured to have the same weight.

According to a third aspect of the present invention, in the scroll type fluid device according to the first or second aspect, a drive mechanism is provided.
The (4) is placed in the upper part of the casing (2), the compression mechanism (3) is placed in the lower part of the casing (2), and the bottom of the casing (2) is used to lubricate the compression mechanism (3). An oil sump (2a) in which lubricating oil is stored is provided. Further, on the lower surface of the compression mechanism (3), discharge space forming members (21) and (22) that form a discharge space (B) communicating with the discharge side of the working chamber (14) between the lower surface are attached, Balance weight (20b) below the compression mechanism (3)
Is located inside the discharge space (B).

According to a fourth aspect of the present invention, in the scroll type fluid device according to the third aspect, the space (A) above the compression mechanism (3) is communicated with the discharge side of the working chamber (13) to perform compression. The mechanism (3) has an oil return passageway (23), one end of which opens into the upper space (A) and the other end of which opens into the oil sump (2a) while avoiding the discharge space (B). There is.

According to a fifth aspect of the present invention, in the scroll type fluid device according to the third or fourth aspect, the lower end of the drive shaft (8) is rotated on the upper surfaces of the discharge space forming members (21), (22). It is configured to be placed freely.

[0016]

With the above construction, the present invention provides the following actions. In the invention according to claim 1, as the fluid compression operation, when the device is driven, the pair of scrolls (10, 11) and (12) make a relative orbital motion, and the fluid is respectively scrolled (10, 11). , (12) wrap (10b, 11b), (12b, 12c) is introduced into the working chamber (13), (14) formed between (14), after compression,
Discharge from the working chambers (13), (14). During such driving, the balance weights (20a), (20b) provided on both sides of the compression mechanism (3) and the weights of the balance weights (20a), (20b) can be set by setting the weights appropriately. The centrifugal force generated by the eccentric rotation of the eccentric part (8b) of the drive shaft (8) is canceled by 20b). Therefore, the individual balance weights (2
0a) and (20b) The centrifugal force can be satisfactorily offset while the weight is significantly reduced.

According to the second aspect of the present invention, the balance weights (20a) and (20b) can be made common, the balance weights (20a) and (20b) can be easily designed, and the manufacturing work can be performed. Is also simplified.

In the third aspect of the invention, the discharge space (B) in which the lower balance weight (20b) is located is a high pressure space because it is communicated with the discharge side of the working chamber (14). On the other hand, the oil sump (2a) is a space having a pressure slightly lower than that of the discharge space (B). Therefore, due to the differential pressure in each space, the oil level of the lubricating oil in the discharge space (B)
It is lower than the oil level in a). In other words, since the oil level around the lower balance weight (20b) is low, the balance weight (20b) is prevented from being immersed in the lubricating oil, and the lubricating oil rotates the drive shaft (8). Can be avoided.

In the invention according to claim 4, the lubricating oil reaching the upper side of the compression mechanism (3) is stored in the oil sump (2
It will be collected in a). With regard to this recovery operation, the oil return passageway (23) is provided separately from the communication passageways of the spaces (A) and (B), so it is obstructed by the flow of discharge gas flowing from the space (B) to the space (A). Without being collected in the oil sump (2a).

According to the fifth aspect of the present invention, the discharge space forming members (21), (22) can be made to serve both as the thrust bearing of the drive shaft (8) and the muffler mechanism.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. The scroll type fluid device according to this example is used as a compressor for a refrigerator, and compresses and discharges a refrigerant gas.

As shown in FIG. 1, the scroll type fluid device (1) has a closed casing (2), and a lower part inside the scroll type fluid device (1) serves as a compression mechanism for sucking and compressing and discharging a refrigerant gas. The scroll mechanism (3) and the drive mechanism (4) at the top for driving the scroll mechanism (3)
Are housed respectively. In addition, a suction pipe (5) for sucking the refrigerant gas is provided on a side wall of the casing (2) at a position corresponding to the scroll mechanism (3) so as to project laterally. Discharge pipes (6) for discharging the compressed refrigerant gas to the outside are respectively projected on the upper surface.

The drive mechanism (4) comprises an electric motor (7) and a crankshaft (8) as a drive shaft connected thereto. Electric motor
(7) is a stator fixed to the inner wall of the casing (2)
(7a) and a rotor (7b) inserted in the stator (7a). The upper part of the crankshaft (8) is inserted into the rotor (7b), and the lower part of the crankshaft (8) penetrates the scroll mechanism (3) to the vicinity of the lower end of the casing (2). The crankshaft (8) extends and the lower end of the crankshaft (8) is configured as an oil supply pump (8a), and the oil supply pump (8a) is immersed in the lubricating oil stored in the oil sump (2a) below the casing (2). Has been done. In addition, the crankshaft (8) has an oil pump (8a)
An oil supply passage (not shown) for supplying the lubricating oil pumped up by the scroll mechanism (3) is formed therethrough.

The scroll mechanism (3) comprises a pair of upper and lower fixed scrolls (10), (11). Each fixed scroll (1
0) and (11) are formed integrally with the casing (2). The upper fixed scroll (10) is a disk-shaped end plate (10a)
An involute-shaped wrap (10b) is erected on the lower surface of the. Also, in the center of the end plate (10a) of the upper fixed scroll (10), the crankshaft
A central hole (10c) for inserting (8) is formed.

The lower fixed scroll (11) is substantially symmetrical to the upper fixed scroll (10) described above. In other words, the wrap (11b) formed in a spiral shape (involute shape) is erected on the upper surface of the disk-shaped end plate (11a). In addition, the end plate (11
A central hole (11c) for inserting the crankshaft (8) is formed in the center of (a).

The fixed scrolls (10) and (11) thus formed are arranged so that the wraps (10b) and (11b) face each other.

The upper and lower fixed scrolls (10),
An orbiting scroll (12) is arranged between the (11) and (11).
This orbiting scroll (12) is a wrap formed in a spiral shape (involute shape) on the upper and lower surfaces of a disk-shaped end plate (12a).
(12b) and (12c) are erected, respectively, and are arranged so as to mesh with the wraps (10b) and (11b) of the fixed scrolls (10) and (11) facing each other. And the orbiting scroll
On the upper surface side of the end plate (12a) of (12), the inner and outer wall surfaces of the upper wrap (12b) of the orbiting scroll (12) are the outer peripheral side of the wrap (10b) of the upper fixed scroll (10). And the inner peripheral wall surface is meshed with each other at a plurality of positions in the spiral direction, and a working chamber (13) for compressing the refrigerant gas is formed between the meshing portions. On the other hand, the end plate (12a) of the orbiting scroll (12)
On the underside of the orbiting scroll (12), the underside wrap (12
Similarly, a working chamber (14) for compressing the refrigerant gas is formed between the c) and the wrap (11b) of the lower fixed scroll (11).

A central hole for inserting the eccentric portion (8b) of the crankshaft (8) is provided in the central portion of the orbiting scroll (12).
(12d) is formed, and the edge of this center hole (12d) has approximately the same height dimension as the wraps (12b), (12c), and the upper and lower end faces have respective fixed scrolls (10). A boss portion (12e) which is set so as to be close to the inner surface of (11) and extends vertically is formed. Further, the eccentric portion (8b) of the crankshaft (8) has its axis (P) slightly eccentric with respect to the axis (Q) of the crankshaft (8). Therefore, when the crankshaft (8) rotates due to the drive of the drive mechanism (4), the orbiting scroll (12) revolves around the axis (Q) of the crankshaft (8) and revolves around the working chamber (13),
It is designed to contract (14).

Further, the discharge holes (10) for communicating the working chambers (13), (14) with the internal spaces (A), (B) of the closed casing (2).
d) and (11d) are formed on the fixed scrolls (10) and (11), respectively. Specifically, the discharge hole (10d) formed in the upper fixed scroll (10) has a working chamber (13) whose one end is on the upper side.
Of the upper fixed scroll (10) to the casing inner space (A) on the upper side, respectively, and the refrigerant gas compressed in the upper working chamber (13) flows into the upper casing inner space. It is designed to discharge to (A). Also,
Discharge hole (11d) formed in the lower fixed scroll (11)
Has one end at the center of the lower working chamber (14) and the other end at the lower fixed scroll (11) lower casing internal space (B)
The refrigerant gas compressed in the lower working chamber (14) is discharged to the lower casing internal space (B).

Further, in each fixed scroll (10), (11),
Through holes (10e), (11e) are formed to guide the refrigerant gas discharged from the lower working chamber (14) to the lower casing inner space (B) to the upper casing inner space (A). ing.

The crankshaft (8) and each scroll (1
Lubricating oil is supplied between 0), (11) and (12) from the oil supply passage.

Further, an Oldham ring (15) as a rotation preventing member (not shown) for preventing rotation of the orbiting scroll (12) and performing a predetermined revolving motion is provided on the outer peripheral edge of the orbiting scroll (12). It is provided (see FIG. 3).

Then, one of the characteristic configurations of this example is as follows.
It is on the balance weight (20) for balancing the rotating system of this device. This balance weight (20) is a drive mechanism.
It is intended to cancel the centrifugal force generated by the eccentric part (8b) of the crankshaft (8) during the rotation of (4), and is located above the scroll mechanism (3) of the crankshaft (8). It consists of a balance weight (20a) and a lower balance weight (20b) located on the lower side. That is,
The pair of balance weights (20a), (20b) are arranged so as to sandwich the scroll mechanism (3).

Further, each of these balance weights (20a), (2
0b) is located in the direction opposite to the eccentric direction of the eccentric part (8b) of the crankshaft (8), and the distances from the eccentric part (8b) are set equal to each other and set to the same weight. ing. And, as each weight of each of the balance weights (20a), (20b), it is possible to obtain a centrifugal force which is about a half of the centrifugal force generated by the weight of the part of the eccentric part (8b) which is bulged in the eccentric direction. The weights are set respectively to cancel the centrifugal force generated around the eccentric portion (8b) when the crankshaft (8) rotates.

Next, other characteristic parts of this example will be described. First, the structure for supporting the lower end of the crankshaft (8) will be described. On the lower surface of the lower fixed scroll (11), there is attached a shaft support member (21) which constitutes a discharge space forming member having an inverted hat type cross-sectional shape. The space (B) is formed between the lower surface of the scroll (11) and the discharge side of the lower working chamber (14) as the discharge space. Also, this shaft support member (21)
Is attached to the lower surface of the fixed scroll (11) below the outer periphery of the through hole (11e) so that the lower end of the through hole (11e) is located in the space (B). Has been. More specifically, as shown in FIG. 2, the vertical wall portion (21a) of the shaft support member (21) has a substantially cylindrical shape arranged concentrically with the casing (2), and has an inner wall surface of the casing (2). It is arranged at a position with a predetermined space between the through hole (11e)
Only the portion facing the arrangement portion is formed in the bulging portion (21b) bulging to the outer peripheral side, and the lower end opening of this through hole (11e) is located in the space (B).

Further, in the central portion of the shaft support member (21),
A circular opening (21 mm) with a diameter larger than that of the crankshaft (8)
c) is formed, and the lower edge of this opening (21c) is
A thrust plate (22) is attached so as to close the opening (21c) from below. The crankshaft (8) is placed on the upper surface of the thrust plate (22), and the crankshaft (8) is supported in the thrust direction.

Due to such a constitution, the shaft support member
The space (B) formed between (21) and the lower surface of the lower fixed scroll (11) is defined by the lower discharge hole (11d) as the working chamber (14).
Through the through holes (10e), (11e) formed in the fixed scrolls (10), (11) to the upper casing inner space (A), which functions as a so-called muffler. Is configured to fulfill. In addition, a slight gap is formed in the connecting portion between the shaft supporting member (21) and the lower fixed scroll (11) and the connecting portion between the shaft supporting member (21) and the thrust plate (22). Internal space of member (21)
(B) and the oil sump (2a) communicate with each other through this gap. Therefore, when high-pressure refrigerant gas is introduced into the internal space (B) of the shaft support member (21), this pressure is introduced into the oil sump (2a) through the gap, but the pressure here Due to the loss, the pressure in the oil sump (2a) is
It is designed to be set lower than the pressure in (B).

In addition, each fixed scroll (10), (11),
Oil return passages (23), (23) are formed. As shown in FIGS. 2 and 3, the oil return passages (23) and (23) are located farther than the vertical wall portion (21a) of the shaft support member (21) in the fixed scrolls (10) and (11). It is formed so as to penetrate vertically at a position on the outer peripheral side. In other words, the upper ends of the oil return passages (23), (23) are open to the upper casing internal space (A),
The lower end is open to the oil sump (2a) at the bottom of the casing.
That is, the oil return passages (23), (23) are connected to the shaft support member (2
It is formed as a passage that is not opened in the space (B) formed between 1) and the lower surface of the lower fixed scroll (11).

Next, the compression operation of the scroll type fluid device (1) constructed as described above will be explained. Electric motor
When (7) is driven, the crank shaft (8) rotates around the shaft center (Q). At this time, the eccentric part (8b) is
It revolves around the axis (Q) of (8). Along with this, the orbiting scroll (12), through which the eccentric portion (8b) is inserted, revolves around the fixed scrolls (10), (11). Further, the orbiting scroll (12) does not rotate due to the rotation preventing member. As a result, on the upper and lower sides of the end plate (12a) of the orbiting scroll (12), the opposing wraps (10b), (12b), (11b), (12b)
The meshing points in c) move toward the center. With this movement, the working chambers (13) and (14) are contracted while moving spirally toward the center. By this series of operations, low-pressure refrigerant gas flows from the suction pipe (5) to the working chambers (13), (14).
Into the working chambers (13), (1
Reach the center of 4). Then, the refrigerant gas compressed in the upper working chamber (13) is discharged from the upper discharge hole (10d) to the upper casing internal space (A) and then discharged from the discharge pipe (6). On the other hand, the refrigerant gas compressed in the lower working chamber (14) is discharged from the lower discharge hole (11d) into the internal space (B) of the shaft support member (21), and from this space (B). After passing through the through holes (10e) and (11e) formed in the fixed scrolls (10) and (11), it is led out to the upper casing internal space (A) and the discharge pipe
It is discharged from (6).

In such a compression operation, the balance weights (20a), (20b) rotate integrally with the crankshaft (8), and the eccentric portion (8b) of the crankshaft (8) rotates. The centrifugal force that accompanies it is offset well, and the balance of the rotating system of this device is maintained.

Thus, in the configuration of this example, the balance weights (20a) and (20b) are installed on both sides of the scroll mechanism (3) at the same distance from the eccentric part (8b) of the crankshaft (8), Further, by setting the weights to be equal to each other, it is possible to satisfactorily cancel the centrifugal force while significantly reducing the weight of each balance weight (20a), (20b). That is, according to the configuration of this example, it is not necessary to provide a large counterweight as in the conventional case, so that the stirring loss generated by the swiveling motion of the counterweight can be significantly reduced and the compression efficiency can be improved. Can be planned.

Further, in the structure of this example, the internal space (B) of the shaft support member (21) is in a high pressure state, whereas the oil sump (2a) is a relatively lower pressure space than the space (B). Therefore, the pressure difference suppresses the introduction of the lubricating oil into the internal space (B) of the shaft support member (21). In other words, the oil level is locally lowered inside this space (B), and the lower balance weight (20b) is located at the part where this oil level is lowered.
Will be installed. Therefore, the balance weight (20b) is suppressed from being immersed in the lubricating oil, and as in the conventional case, the weight is rotated while being immersed in the lubricating oil to increase the resistance to the rotation of the crankshaft (8). Can be avoided, and the mechanical efficiency of the device can be improved.

Also, during this compression operation, the oil supply pump (8a)
Lubricating oil pumped by is supplied to the bearing part around the crankshaft (8) through the oil supply passage, and
The crankshaft (8) is lubricated so as to rotate smoothly with respect to (10), (11), and (12). Then, a part of this lubricating oil reaches the upper surface of the upper fixed scroll (10), and is introduced into the upper casing internal space (A) together with the refrigerant gas and separated from the refrigerant gas in this space (A). The lubricating oil also reaches the upper surface of the upper fixed scroll (10). Then, these lubricating oils are collected in the oil sump (2a) from the oil return passages (23) formed in the fixed scrolls (10), (11). In this recovery operation, the oil return passageway (23) has its upper end opened to the high-pressure upper casing internal space (A), while its lower end is opened to the oil sump (2a). It is smoothly collected in the oil sump (2a) by its own weight without being disturbed by the flow of discharge gas from 14). As described above, since the refrigerant gas flow passage and the lubricating oil recovery passage are individually provided so that the lubricating oil recovery operation is not hindered, the oil rise in the oil sump is reliably suppressed.

Although the compressor for the refrigerator has been described in this example, the scroll type fluid device (1) of the present invention may be used for a vacuum pump, an expander or the like.

In this example, the scroll mechanism (3) is provided on the lower side of the casing (2), but the scroll mechanism (3) is provided on the upper side of the casing (2). , Balance weights (2
0a) and (20b) may be arranged.

The present invention is not limited to a scroll scroll provided between a pair of fixed scrolls, but can be applied to a scroll scroll provided between a pair of fixed scrolls.

[0047]

As described above, according to the present invention, the following effects are exhibited. According to the invention of claim 1, the drive shaft is provided with a balance weight for canceling a centrifugal force generated by the eccentric rotation of the eccentric portion.
Since the balance weights are provided on both sides of the compression mechanism in the extension direction of the drive shaft, if the balance weights are arranged at appropriate positions and weights, the centrifugal force generated by the eccentric rotation of the eccentric part of the drive shaft is generated by the balance weights. Are offset.
Therefore, the weight of each balance weight can be significantly reduced while the conventional counterweight is eliminated, and the centrifugal force can be canceled well. Therefore, since it is not necessary to provide a large counterweight as in the conventional case, it is possible to significantly reduce the stirring loss that has been caused by the swiveling motion of the counterweight, and it is possible to improve the compression efficiency.

According to the second aspect of the present invention, each balance weight is provided in a direction opposite to the eccentric direction of the eccentric portion of the drive shaft.
In addition, since the balance weights are arranged at positions equidistant from the eccentric portion and are formed to have the same weight, the respective balance weights can be made common, which facilitates the design of the balance weights, and the manufacturing work. Is also simplified. Therefore, it is possible to realize the configuration for obtaining the effect according to the invention described in claim 1.

According to the third aspect of the present invention, the oil level of the lubricating oil in the discharge space can be made lower than the oil level in the oil sump due to the pressure difference between the discharge space and the oil sump, and the compression mechanism Also, the lower balance weight is prevented from being immersed in the lubricating oil, and the lubricating oil can be prevented from becoming a resistance against the rotation of the drive shaft, and the mechanical efficiency of the device can be surely improved.

According to the fourth aspect of the present invention, the lubricating oil can be smoothly recovered without being hindered by the flow of the discharge gas from the space below the compression mechanism, and the oil can be reliably prevented from rising into the refrigeration system. The property is improved.

According to the fifth aspect of the invention, the lower end portion of the drive shaft is rotatably mounted on the upper surface of the discharge space forming member so that the discharge space forming member also serves as the thrust bearing of the drive shaft. Therefore, it is possible to reduce the number of parts while securing the effects according to the inventions of claims 3 and 4.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shaft penetration type double-toothed scroll type fluid device according to an embodiment.

FIG. 2 is a sectional view taken along a line II-II in FIG.

3 is a cross-sectional view at a position corresponding to a line III-III in FIG.

FIG. 4 is a view corresponding to FIG. 1 in a conventional example.

[Explanation of symbols]

(1) Scroll type fluid device (2) Closed casing (3) Scroll mechanism (compression mechanism) (4) Drive mechanism (8) Crankshaft (drive shaft) (8b) Eccentric part (10), (11) Fixed scroll ( 12) Orbiting scroll (10a), (11a), (12a) End plate (10b), (11b), (12b), (12c) Wrap (13), (14) Working chamber (20a), (20b) Balance weight (21) Shaft support member (22) Thrust plate (23) Oil return passage (A) Upper casing inner space (B) Lower casing inner space (Discharge space)

Claims (5)

[Claims] 1. A spiral wrap on an end plate (10a, 11a), (12a).
(10b, 11b), (12b, 12c) are erected, and each lap (10b, 11b),
(12b, 12c) meshes with each other to form working chambers (13), (14), and includes at least a pair of scrolls (10, 11), (12) arranged so that relative swivel motion is possible. Compression mechanism (3)
And an eccentric part (8b) is formed in a part so that the pair of scrolls (10, 11), (12) perform a relative orbital motion, and the eccentric part (8b) is compressed by the compression mechanism (3 ) And a drive mechanism (4) having a drive shaft (8) linked to the housing (2) are housed in the casing (2), and a pair of eccentric parts (8b) are eccentrically rotated by the rotation of the drive shaft (8). After the scrolls (10, 11) and (12) perform relative swirling motion to introduce the fluid into the working chambers (13) and (14), the internal volumes of the working chambers (13) and (14) are changed. In a scroll type fluid device which is configured to contract and compress, the drive shaft (8) penetrates the compression mechanism (3) and
One end on the side opposite to the side where (4) is installed is a compression mechanism.
The drive shaft (8) is projected from (3), and balance weights (20a), (2) for canceling centrifugal force generated by eccentric rotation of the eccentric part (8b)
0b) is provided on both sides of the compression mechanism (3) in the extension direction of the drive shaft (8). 2. Each balance weight (20a), (20b) is in the direction opposite to the eccentric direction of the eccentric part (8b) of the drive shaft (8) and is equidistant from the eccentric part (8b). The scroll type fluid device according to claim 1, wherein the scroll type fluid devices are arranged at respective positions and are formed with the same weight. 3. The drive mechanism (4) is arranged in the upper part of the casing (2), the compression mechanism (3) is arranged in the lower part of the casing (2), and the bottom part of the casing (2) is Compression mechanism
An oil sump (2a) is provided to store lubricating oil for lubricating (3), and the lower surface of the compression mechanism (3) is connected to the discharge side of the working chamber (14) between the lower surface and the lower surface. The discharge space forming members (21) and (22) that form the communicating discharge space (B) are attached, and the balance weight (20b) below the compression mechanism (3) has this discharge space (B).
The scroll type fluid device according to claim 1 or 2, wherein the scroll type fluid device is located inside. 4. The space (A) above the compression mechanism (3) is
It communicates with the discharge side of the working chamber (13), and one end of the compression mechanism (3) opens into the upper space (A) and the other end avoids the discharge space (B) and holds the oil sump ( Oil return passage (23) opening to 2a)
The scroll type fluid device according to claim 3, wherein the scroll type fluid device is provided. 5. The lower end of the drive shaft (8) is rotatably mounted on the upper surfaces of the discharge space forming members (21), (22). Scroll type fluid device.