EP3388673A1

EP3388673A1 - Scroll compressor

Info

Publication number: EP3388673A1
Application number: EP17752966.6A
Authority: EP
Inventors: Yoshiaki Miyamoto; Yoshiyuki Kimata; Hajime Sato; Toshiyuki Goto; Takashi Watanabe
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2016-02-19
Filing date: 2017-02-01
Publication date: 2018-10-17
Also published as: CN108431419A; EP3388673A4; KR20180094056A; AU2017220218A1; WO2017141703A1; JP2017145806A; AU2017220218B2; JP6704751B2

Abstract

A scroll compressor is provided with: an annular thrust plate (32) provided within a housing and having a thrust bearing surface (32S) in contact with the rear surface of the end plate (21A) of an orbiting scroll (21); and a main balance weight (41) provided to a drive shaft (9) so as to be axially adjacent to the thrust plate (32) and cancelling centrifugal force caused by the eccentric orbiting movement of the orbiting scroll (21). The main balance weight (41) has a decreasing outer diameter section (41a) provided at the thrust plate (32)-side end of the main balance weight (41), the decreasing outer diameter section (41a) having an outer diameter gradually decreasing toward the thrust plate (32). The thrust plate (32) has an increasing inner diameter section (32a) on the main balance weight (41) side of the inner diameter section of the thrust plate (32), the increasing inner diameter section (32a) having an inner diameter gradually increasing toward the main balance weight (41). The decreasing outer diameter section (41a) and the increasing inner diameter section (32a) overlap each other in the radial direction and the axial direction.

Description

Technical Field

The present invention relates to a scroll compressor which compresses a refrigerant.

Background Art

As shown in Fig. 1 of PTL 1, a scroll compressor which compresses a refrigerant has a compression mechanism which includes a fixed scroll which is fixed inside a housing and an orbiting scroll which faces the fixed scroll so as to mesh with the fixed scroll. A cylindrical boss portion is formed at a center portion of a rear surface of an end plate of the orbiting scroll, a drive bush is rotatably fitted to the boss portion via a bearing, and an eccentric pin (crank pin) of the drive shaft is fitted to the drive bush. A rotation of the orbiting scroll is restricted by Oldham ring (rotation prevention mechanism).
If the drive shaft is rotationally driven by a drive source such as an engine or a motor, the orbiting scroll performs an eccentric orbiting movement with respect to the fixed scroll while the rotation of the orbiting scroll is restricted. Accordingly, a volume of a compression space formed between both scrolls is continuously changed, the refrigerant is sucked from a suction port when the volume is expanded, the refrigerant is compressed when the volume is decreased, and the compressed refrigerant is discharged from a discharge port at a timing after the refrigerant is maximally compressed.
As described above, the orbiting scroll performs the eccentric orbiting movement with respect to the fixed scroll, and thus, a rotational vibration is generated in the drive shaft by a weight unbalance as it is. In order to eliminate the weight unbalance, a balance weight is provided in which a weight is arranged in the direction opposite to an eccentric direction of the orbiting scroll on a drive bush or the drive shaft itself, and thus, a centrifugal force caused by the eccentric orbiting movement of the orbiting scroll is cancelled so as to suppress the rotational vibration.
When the scroll compressor is operated, the orbiting scroll is pressed in a direction (thrust direction) separated from the fixed scroll by a reaction force of the compressed refrigerant. An annular thrust plate (thrust bearing) is installed inside the housing in order to receive the thrust force. The rear surface of the end plate of the orbiting scroll comes into contact with the thrust bearing surface of the thrust plate and slides relative to each other. By increasing an area of this thrust bearing surface, a thrust load per unit area is decreased, an oil film between both members is secured, the orbiting scroll smoothly performs the eccentric orbiting movement, and it is possible to prevent abrasion of the end plate of the orbiting scroll and the thrust plate.

Citation List

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2011-214474

Summary of Invention

Technical Problem

In the scroll compressor, in order to increase capacity of the compression mechanism, it is necessary to increase diameters of the fixed scroll and the orbiting scroll or eccentricity of the orbiting scroll with respect to the fixed scroll. Accordingly, the centrifugal force caused by the eccentric orbiting movement of the orbiting scroll increases. Accordingly, in order to cope with the centrifugal force of the orbiting scroll, it is necessary to increase dimensions of the balance weight provided in the drive bush so as to increase the weight.
In order to increase the dimensions of the balance weight, it is necessary to expand a space around the drive bush, in which the balance weight is installed, in an axial direction and a radial direction. However, if the space is expanded in the axial direction and the radial direction, it is not possible to increase the inner diameter of the thrust plate which is formed annularly. As a result, the area of the thrust bearing surface on which the orbiting scroll and the thrust plate are in contact with each other decreases, a thrust load per unit area increases, and sliding heat generation increases.
The dimensions of the balance weight increase, and thus, a thickness of a bearing member pivotally supporting an intermediate portion of the drive shaft should be made relatively thin, and there is a problem that it is difficult to secure strength of a main bearing and a deflection amount decreases.
The present invention is made in consideration of the above-described circumstances, and an object thereof is to provide a scroll compressor capable of coping with an increase in capacity of a compression mechanism by increasing the dimensions of the balance weight without decreasing the area of the thrust bearing surface and decreasing the strength of the bearing member, by simple configuration.

Solution to Problem

In order to achieve the above-described object, the present invention adopts the following means.
That is, according to an aspect of the present invention, there is provided a scroll compressor, including: a fixed scroll which is fixed inside a housing; an orbiting scroll which faces the fixed scroll so as to mesh with the fixed scroll; a drive shaft which allows the orbiting scroll to perform an eccentric orbiting movement; a bearing member which is provided inside the housing and supports the drive shaft; an annular thrust plate which is installed inside the housing, includes a thrust bearing surface which is in contact with a rear surface of an end plate of the orbiting scroll, and receives a thrust force acting on the orbiting scroll; and a main balance weight which is provided in the drive shaft, is adjacent to the thrust plate in an axial direction, and cancels a centrifugal force caused by the eccentric orbiting movement of the orbiting scroll, in which the main balance weight includes an outer diameter decreasing portion which is provided on an end portion of the main balance weight on the thrust plate side and has an outer diameter which gradually decreases toward the thrust plate side, the thrust plate includes an inner diameter increasing portion which is provided on an inner diameter portion of the thrust plate on the main balance weight side and has an inner diameter which gradually increases toward the main balance weight side, and the outer diameter decreasing portion and the inner diameter increasing portion overlap each other in a radial direction and the axial direction.
According to this configuration, an inner diameter dimension of the thrust plate is increased from the thrust bearing surface side toward the main balance weight side by the inner diameter increasing portion. Accordingly, it is possible to increase a volume of an accommodation chamber of the main balance weight adjacent to the thrust plate in both directions of the radial direction and the axial direction while maintaining the area of the thrust bearing surface to a predetermined size.
Meanwhile, the outer diameter decreasing portion of the main balance weight overlaps the inner diameter increasing portion of the thrust plate in the radial direction and the axial direction. Accordingly, a radial dimension of the main balance weight can increase while an axial dimension of the main balance weight increases toward the thrust plate side.
Accordingly, the dimensions of the main balance weight increase without decreasing the area of the thrust bearing surface in the thrust plate, and thus, it is possible to cope with an increase in capacity of the compression mechanism.
In the scroll compressor having the above-described configuration, the outer diameter decreasing portion may have an outer conical surface shape and the inner diameter increasing portion may have an inner conical surface shape which is parallel to the outer diameter decreasing portion with a gap to face the outer diameter decreasing portion.
Alternatively, the outer diameter decreasing portion may have an outer stepped cylindrical surface shape having at least one step portion and the inner diameter increasing portion may have an inner stepped cylindrical surface shape which meshes with the outer diameter decreasing portion with a gap.
Accordingly, the outer diameter decreasing portion of the main balance weight is reasonably close to the inner diameter incresing portion of the thrust plate so as to increase the dimensions of the main balance weight, and thus, it is possible to cope with the increase in the capacity of the compression mechanism.
In the scroll compressor having the above-described configuration, the main balance weight may be provided to be adjacent to the bearing member in the axial direction and may include an inner peripheral overlap portion which overlaps a radially inner peripheral side of the bearing member, the inner peripheral overlap portion may include an outer diameter decreasing portion having an outer diameter which gradually decreases toward a radial bearing portion side of the bearing member in the axial direction, the bearing member may include an inner diameter increasing portion having an inner diameter which gradually increases toward the inner peripheral overlap portion side, and the outer diameter decreasing portion and the inner diameter increasing portion may overlap each other in a radial direction and the axial direction.
According to this configuration, the outer diameter of the bearing member is changed to a conical cylinder shape toward the inner peripheral overlap portion side of the balance weight in the inner diameter increasing portion. Therefore, for example, compared to a case where the inner diameter increasing portion is configured of a flat surface orthogonal to the axial direction and a cylindrical surface parallel to the axial direction, a thin portion is not generated in the bearing member. Accordingly, it is possible to cope with the increase in the capacity of the compression mechanism by increasing the dimensions of the balance weight (inner peripheral overlap portion) without decreasing the strength of the bearing member, by a simple configuration.
In the scroll compressor having the above-described configuration, the scroll compressor may further include a sub-balance weight which is separated from the main balance weight, in which the sub-balance weight may be provided on an opposite side of the main balance weight with respect to the bearing member so as to be adjacent to the bearing member in the axial direction and may include an outer peripheral overlap portion which overlaps a radially outer peripheral side of the bearing member, the outer peripheral overlap portion may include an inner diameter increasing portion having an inner diameter which gradually increases toward a fixing portion side of the bearing member in the axial direction, the bearing member may include an outer diameter decreasing portion having an outer diameter which gradually decreases toward the outer peripheral overlap portion side, and the inner diameter increasing portion and the outer diameter decreasing portion may overlap each other in a radial direction and the axial direction.
According to this configuration, the outer diameter of the bearing member is changed to a conical cylinder shape toward the outer peripheral overlap portion side of the balance weight in the outer diameter decreasing portion. Therefore, for example, compared to a case where the outer diameter decreasing portion is configured of a flat surface orthogonal to the axial direction and a cylindrical surface parallel to the axial direction, a thin portion is not generated in the bearing member. Accordingly, it is possible to cope with the increase in the capacity of the compression mechanism by increasing the dimensions of the balance weight (outer peripheral overlap portion) without decreasing the strength of the bearing member, by a simple configuration.

Advantageous Effects of Invention

As described above, according to the scroll compressor according to the present invention, it is possible to cope with an increase in capacity of a compression mechanism by increasing the dimensions of the balance weight without decreasing the area of the thrust bearing surface in the thrust plate and decreasing the strength of the bearing member, by simple configuration.

Brief Description of Drawings

Fig. 1 is a longitudinal sectional view of a scroll compressor according to an embodiment of the present invention.
Fig. 2 shows an II portion of Fig. 1 in an enlarged manner and is a longitudinal sectional view in the vicinities of a thrust plate and a balance weight showing a first embodiment of the present invention.
Fig. 3 is a longitudinal sectional view in the vicinities of a thrust plate and a balance weight showing a second embodiment of the present invention.

Description of Embodiments

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Fig. 1 is a longitudinal sectional view of a scroll compressor according to an embodiment of the present invention. For example, a scroll compressor 1 is an open type (a drive shaft protrudes toward the outside) compressor which is driven by an external drive source such as an engine, and includes a cylindrical container shaped housing 2 in which a bottomed front housing 3 and a bottomed rear housing 4 are integrally connected to each other by a plurality of bolts 5.
A bearing member 6 is fixed to an opening end side of the front housing 3 side inside the housing 2, and a drive shaft 9 is rotatably supported by a radial bearing portion 6A of the bearing member 6 and a rolling bearing 8 installed in the front housing 3. The bearing member 6 includes a flange-shaped fixing portion 6B and the fixing portion 6B is fastened and fixed to the front housing 3 by a plurality of bolts 7. One end portion of the drive shaft 9 penetrates the front housing 3 to protrude toward the outside, and power of the external drive source such as the engine is input to the protrusion portion via a pulley 10 and an electromagnetic clutch 11.
The pulley 10 is rotatably supported by an outer periphery of a flange member 13 fixed to a front end surface of the front housing 3 by a bolt 12, via a rolling bearing 14, and a coil assembly 15 of the electromagnetic clutch 11 is incorporated inside the pulley 10. An armature assembly 16 of the electromagnetic clutch 11 is attached to an external protrusion end of the drive shaft 9 via a boss portion 16A by a bolt 17 so as to face the pulley 10. In addition, a mechanical seal 18 for hermetically sealing a through portion of the drive shaft 9 is installed on an inner peripheral side of the flange member 13.
A compression mechanism 19 is incorporated in the rear housing 4 side inside the housing 2. In the compression mechanism 19, a fixed scroll 20 which is fixed inside the housing 2 and an orbiting scroll 21 facing the fixed scroll 20 mesh with each other to be deviated by a phase of 180°, and a pair of compression chambers 22 is formed between both scrolls 20 and 21. The compression mechanism 19 itself is well known.
The fixed scroll 20 is fastened and fixed to the bearing member 6 by a plurality of bolts 23, and a discharge cavity 26 is formed between a rear surface of an end plate 20A and an inner surface of the rear housing 4. A discharge port 24 through which a compressed gas is discharged into the discharge cavity 26 and a discharge valve 25 which opens and closes the discharge port 24 are provided in the end plate 20A of the fixed scroll 20. A discharge port 27 through which the compressed gas discharged into the discharge cavity 26 is discharged to the outside is open to the rear housing 4, and a discharge pipe configuring a refrigerating cycle can be connected to the discharge port 27.
Meanwhile, in the orbiting scroll 21, a cylindrical boss portion 28 is formed at a center portion of a rear surface of an end plate 21A, a cylindrical drive bush 29 is rotatably fitted to the boss portion 28 via the bearing 30, and an eccentric pin 9A provided on the inner peripheral side of the drive shaft 9 is rotatably fitted to the inner peripheral portion of the drive bush 29. Accordingly, if the drive shaft 9 is rotated, the orbiting scroll 21 is driven to be eccentrically orbited via the eccentric pin 9A and the drive bush 29 which are eccentrically rotated.
In the orbiting scroll 21, the rear surface of the end plate 21A is supported by an annular thrust plate 32 which is fixed to the bearing member 6 by a plurality of bolts 31, the rotation of the orbiting scroll 21 is prevented by a well-known rotation prevention mechanism 33 such as an Oldham link or a pin ring interposed between the rear surface of the end plate 21A and the bearing member 6, and the orbiting scroll 21 is driven to be orbited with respect to the fixed scroll 20.
A suction port 34 which is connected to a suction pipe on the refrigerating cycle side is provided on the outer periphery on the front end side of the rear housing 4, and a low-pressure gas sucked into a suction cavity 35 from the suction port 34 is sucked to the compression chamber 22 of the compression mechanism 19 so as to be compressed and is discharged from the discharge port 27 via the discharge port 24 (discharge valve 25) and the discharge cavity 26.
When the compression mechanism 19 is operated, the orbiting scroll 21 is pressed in a direction (thrust direction) separated from the fixed scroll 20 by a reaction force of the refrigerant compressed in the compression chamber 22. Accordingly, the rear surface of the end plate 21A of the orbiting scroll 21 is pressed against the thrust bearing surface 32S of the thrust plate 32, and a thrust force is received by the thrust plate 32. A lubricant is supplied from an oil supply passage (not shown) to a portion between the end plate 21A and the thrust plate 32, and thus, both members 21A and 32 smoothly slide relative to each other.
As described above, the orbiting scroll 21 performs the eccentric orbiting movement with respect to the fixed scroll 20, and thus, a rotational vibration is generated in the drive shaft 9 by a weight unbalance as it is. In order to eliminate the weight unbalance, in the drive shaft 9, a main balance weight 41 and a sub-balance weight 42 are pivotally supported in which weights are arranged in the direction opposite to an eccentric direction of the orbiting scroll 21.
The main balance weight 41 is pivotally supported by the eccentric pin 9A of the drive shaft 9 via the drive bush 29, is accommodated in a balance weight accommodation chamber 6C formed on the inner peripheral side of the bearing member 6, and is orbited in a circumferential direction. The sub-balance weight 42 is installed at an intermediate portion of the drive shaft 9 between the radial bearing portion 6A of the bearing member 6 and the rolling bearing 8, is accommodated in a balance weight accommodation chamber 6D formed on the outer peripheral side of the bearing member 6, and is orbited in the circumferential direction.
That is, the main balance weight 41 and the sub-balance weight 42 are provided to be adjacent to one side and the other side in the axial direction with respect to the bearing member 6. In other words, the bearing member 6 is interposed between the main balance weight 41 and the sub-balance weight 42. The balance weights 41 and 42 are provided, and thus, a centrifugal force caused by the eccentric orbiting movement of the orbiting scroll 21 is cancelled, and thus, the rotational vibration is suppressed.

[First Embodiment]

Fig. 2 shows an II portion of Fig. 1 in an enlarged manner and is a longitudinal sectional view in the vicinities of the thrust plate 32, the main balance weight 41, and the sub-balance weight 42 showing a first embodiment of the present invention.
As described above, the main balance weight 41 is provided on the drive shaft 9 to be adjacent to the bearing member 6 in an axial direction and includes an inner peripheral overlap portion 41A which overlaps a radially inner peripheral side of the bearing member 6. The inner peripheral overlap portion 41A becomes a substantial weight portion and is orbited in the circumferential direction in the balance weight accommodation chamber 6C. A C-chamfered outer diameter decreasing portion 41a is formed on the outer peripheral surface in an end portion of the inner peripheral overlap portion 41A on the thrust plate 32 side. The outer diameter decreasing portion 41a has an outer conical surface shape having an outer diameter which gradually decreases toward the thrust plate 32 side.
Meanwhile, in the thrust plate 32, a C-chamfered inner diameter increasing portion 32a is formed in the inner diameter portion on the main balance weight 41 (inner peripheral overlap portion 41A) side. The inner diameter increasing portion 32a has an inner conical surface shape having an inner diameter which gradually increases toward the main balance weight 41 (41A) side. The outer diameter decreasing portion 41a of the main balance weight 41 (41A) and the inner diameter increasing portion 32a of the thrust plate 32 overlap each other in a radial direction and in the axial direction, and are parallel to each other with a predetermined gap to face each other.
An inclination angle of a conical surface of each of the outer diameter decreasing portion 41a and the inner diameter increasing portion 32a is set to approximately 30° to 60° based on an axis of the drive shaft 9. An inclined surface of the inner diameter increasing portion 32a intersects the thrust bearing surface 32S, the inner diameter of the thrust bearing surface 32S increases, and an area of the thrust bearing surface 32S decreases. Accordingly, preferably, the inclination angle of the inner diameter increasing portion 32a is set such that the inclined surface of the inner diameter increasing portion 32a and the thrust bearing surface 32S do not intersect each other.
The thrust plate 32 is detachably fixed to the bearing member 6 by the bolt 31 (refer to Fig. 1), and thus, the main balance weight 41 can be attached to or detached from the balance weight accommodation chamber 6C by loosening the bolt 31 so as to remove the thrust plate 32.
A C-chamfered outer diameter decreasing portion 41b is formed on an end portion of the inner peripheral overlap portion 41A of the main balance weight 41 on the radial bearing portion 6A side. The outer diameter decreasing portion 41b has an outer conical surface shape having an outer diameter which gradually decreases toward the radial bearing portion 6A side in the axial direction.
Meanwhile, an inner diameter increasing portion 6a is formed in the bearing member 6. The inner diameter increasing portion 6a has an inner conical surface shape having an inner diameter which gradually increases toward the inner peripheral overlap portion 41A side. The inner diameter increasing portion 6a and the outer diameter decreasing portion 41b of the inner peripheral overlap portion 41A overlap each other in the radial direction and the axial direction, and are parallel to other with a predetermined gap to face each other.
The sub-balance weight 42 is provided on an opposite side of the main balance weight 41 with respect to the bearing member 6 so as to be adjacent to the bearing member 6 in the axial direction and includes an outer peripheral overlap portion 42A which overlaps the radially outer peripheral side of the bearing member 6. The outer peripheral overlap portion 42A becomes a substantial weight portion and is orbited in the circumferential direction in the balance weight accommodation chamber 6D. The outer peripheral overlap portion 42A includes an inner diameter increasing portion 42a having an inner conical surface shape which has an inner diameter which gradually increases toward the fixing portion 6B side of the bearing member 6 in the axial direction.
Meanwhile, in the bearing member 6, an outer diameter decreasing portion 6b having an outer diameter which gradually decreases toward the outer peripheral overlap portion 42A side of the sub-balance weight 42 is formed, and the outer diameter decreasing portion 6b and the inner diameter increasing portion 42a of the outer peripheral overlap portion 42A overlap each other in the axial direction and the radial direction and are parallel to each other with a predetermined gap to face each other.
According to the scroll compressor 1 having the above-described configuration, the following effects are exerted.
That is, in the scroll compressor 1, the inner diameter increasing portion 32a having the inner diameter which gradually increases toward the main balance weight 41 side is formed on the inner diameter portion of the thrust plate 32 on the main balance weight 41 (41A) side while the outer diameter decreasing portion 41a having the outer diameter which gradually decreases toward the thrust plate 32 side is formed on the end portion of the main balance weight 41 (inner peripheral overlap portion 41A) on the thrust plate 32 side, and the outer diameter decreasing portion 41a of the main balance weight 41 and the inner diameter increasing portion 32a of the thrust plate 32 overlap each other in the radial direction and the axial direction.
According to this configuration, an inner diameter dimension of the thrust plate 32 is increased from the thrust bearing surface 32S side toward the main balance weight 41 (41A) side by the inner diameter increasing portion 32a. Accordingly, it is possible to increase the volume of the balance weight accommodation chamber 6C adjacent to the thrust plate 32 in both directions of the radial direction and the axial direction while maintaining the area of the thrust bearing surface 32S to a predetermined size.
As described above, the outer diameter decreasing portion 41a of the main balance weight 41 overlaps the inner diameter increasing portion 32a of the thrust plate 32 in the radial direction and the axial direction, and thus, a radial dimension of the main balance weight 41 can increase while an axial dimension of the main balance weight 41 increases toward the thrust plate 32 side.
In the thrust plate 32, the area (width in the radial direction) of the thrust bearing surface 32S does not decrease according to the increase of the outer diameter of the main balance weight 41 (41A), and a contact area between the orbiting scroll 21 (end plate (21A)) and the thrust plate 32 (thrust bearing surface 32S) can be sufficiently secured.
Accordingly, the dimensions of the main balance weight 41 (41A) increase without decreasing the area of the thrust bearing surface 32S in the thrust plate 32, and thus, it is possible to cope with an increase in capacity of the compression mechanism 19.
The outer diameter decreasing portion 41a of the main balance weight 41 (41A) has an outer conical surface shape and the inner diameter increasing portion 32a of the thrust plate 32 has an inner conical surface shape which is parallel to the outer diameter decreasing portion 41a with a gap to face the outer diameter decreasing portion. Accordingly, the outer diameter decreasing portion 41a of the main balance weight 41 is reasonably close to the inner diameter increasing portion 32a of the thrust plate 32 so as to increase the dimensions of the main balance weight 41 (41A), and thus, it is possible to cope with the increase in the capacity of the compression mechanism 19.
The inner peripheral overlap portion 41A of the main balance weight 41 overlaps the radially inner peripheral side of the bearing member 6, the outer diameter decreasing portion 41b having the outer diameter which gradually decreases toward the radial bearing portion 6A side in the axial direction is formed on the inner peripheral overlap portion 41A, the inner diameter increasing portion 6a having the inner diameter which gradually increases toward the inner peripheral overlap portion 41A side is formed on the bearing member 6, and the inner diameter increasing portion 6a and the outer diameter decreasing portion 41b overlap each other in the radial direction and the axial direction.
According to this configuration, an outer diameter of an intermediate portion of the bearing member 6, that is, an outer diameter of a portion between the radial bearing portion 6A and the fixing portion 6B is increased to form a conical cylindrical shape toward the inner peripheral overlap portion 41A side of the main balance weight 41 by the inclined surface shape of the inner diameter increasing portion 6a. Therefore, for example, compared to a case where the inner diameter increasing portion 6a is configured of a flat surface orthogonal to the axial direction and a cylindrical surface parallel to the axial direction as shown by an imaginary line E in Fig. 2, a thin portion is not generated in the bearing member 6. Accordingly, the strength of the bearing member 6 is highly maintained and a deflection amount decreases. Accordingly, it is possible to cope with the increase in the capacity of the compression mechanism 19 by increasing the dimensions of the main balance weight 41 (inner peripheral overlap portion 41A) without decreasing the strength of the bearing member 6, by a simple configuration.
In the drive shaft 9, the sub-balance weight 42 separated from the main balance weight 41 is provided on an opposite side of the main balance weight 41 with respect to the bearing member 6 so as to be adjacent to the bearing member 6 in the axial direction. The sub-balance weight 42 includes the outer peripheral overlap portion 42A which overlaps the radially outer peripheral side of the bearing member 6, and the inner diameter increasing portion 42a having the inner diameter which gradually increases toward the fixing portion 6B side of the bearing member 6 in the axial direction is formed on the outer peripheral overlap portion 42A. Meanwhile, the outer diameter decreasing portion 6b which gradually decreases toward the outer peripheral overlap portion 42A side is formed on the bearing member 6, and the outer diameter decreasing portion 6b and the inner diameter increasing portion 42a overlap each other in the radial direction and the axial direction.
According to this configuration, the outer diameter of the intermediate portion of the bearing member 6 is changed to a conical cylinder shape toward the outer peripheral overlap portion 42A side of the balance weight 42 by the inclined surface shape of the outer diameter decreasing portion 6b. Therefore, for example, compared to a case where the outer diameter decreasing portion 6b is configured of a flat surface orthogonal to the axial direction and a cylindrical surface parallel to the axial direction as shown by an imaginary F in Fig. 2, a thin portion is not generated in the bearing member 6. Accordingly, the strength of the bearing member 6 is highly maintained and a deflection amount decreases. Accordingly, it is possible to cope with the increase in the capacity of the compression mechanism 19 by increasing the dimensions of the sub-balance weight 42 (outer peripheral overlap portion 42A) without decreasing the strength of the bearing member 6, by a simple configuration.

[Second Embodiment]

Fig. 3 is a longitudinal sectional view in the vicinities of the thrust plate 32 and the main balance weight 41 and the sub-balance weight 42 showing a second embodiment of the present invention. In Fig. 3, an inner peripheral surface of the thrust plate 32 and an end portion shape of the main balance weight 41 (inner peripheral overlap portion 41A) on the thrust plate 32 side are different from those of the first embodiment shown in Fig. 2, and other than that, the second embodiment have the same configurations as those of the first embodiment. Accordingly, the same reference numerals as those of Fig. 2 are assigned to the same portions, and descriptions thereof are omitted.
In the second embodiment, an outer diameter decreasing portion 41c having an outer stepped cylindrical surface shape including at least one step portion is formed on an end portion of the main balance weight 41 (41A) on the thrust plate 32 side. An inner diameter increasing portion 32b having an inner stepped cylindrical surface shape which meshes with the outer diameter decreasing portion (41c) with a gap is formed on the thrust plate 32.
Accordingly, like the combination between the outer diameter decreasing portion 41a of the main balance weight 41 (41A) having the outer conical surface shape and the inner diameter increasing portion 32a of the thrust plate 32 having the inner conical surface shape in the first embodiment (Fig. 2), the outer diameter decreasing portion 41c of the main balance weight 41 (41A) is reasonably close to the inner diameter increasing portion 32b of the thrust plate 32 so as to increase the dimensions of the main balance weight 41 (41A) in the radial direction and the axial direction, and thus, it is possible to cope with the increase in the capacity of the compression mechanism 19.
Each of the outer diameter decreasing portion 41c and the inner diameter increasing portion 32b is formed in a stepped cylindrical surface shape, and thus, it is possible to easily machine the outer diameter decreasing portion 41c and the inner diameter increasing portion 32b compared to the outer diameter decreasing portion 41a and the inner diameter increasing portion 32a of the first embodiment having a conical surface shape. Each of the outer diameter decreasing portion 41c and the inner diameter increasing portion 32b may be formed to have two or more steps.
The configuration having the stepped cylindrical surface shape may be applied to a facing portion between the inner diameter increasing portion 6a of the bearing member 6 and the outer diameter decreasing portion 41b of the main balance weight 41 (41A) and a facing portion between the outer diameter decreasing portion 6b of the bearing member 6 and the inner diameter increasing portion 42a of the sub-balance weight 42 (42A).
The present invention is not limited only to the configurations of the above-described embodiments, a modification or an improvement can be appropriately applied to the present invention, and an embodiment to which the modification or the improvement is applied is included in the scope of the present invention.
For example, in the above-described embodiments, the example is described, in which the present invention is applied to an open type scroll compressor 1 in which the drive shaft 9 is rotationally driven by the external power. However, the present invention can be applied to a close type scroll compressor in which the drive shaft is rotationally driven by a built-in electric motor. Reference Signs List

1: scroll compressor
2: housing
6: bearing member (main bearing)
6A: radial bearing portion
6B: fixing portion of bearing member
6a: inner diameter increasing portion
6b: outer diameter decreasing portion
9: drive shaft
20: fixed scroll
21: orbiting scroll
21A: end plate of orbiting scroll
32: thrust plate
32S: thrust bearing surface
32a, 32b: inner diameter increasing portion
41: main balance weight
41A: inner peripheral overlap portion
41a, 41b, 41c: outer diameter decreasing portion
42: sub-balance weight
42A: outer peripheral overlap portion
42a: inner diameter increasing portion

Claims

A scroll compressor, comprising:
a fixed scroll which is fixed inside a housing;

an orbiting scroll which faces the fixed scroll so as to mesh with the fixed scroll;

a drive shaft which allows the orbiting scroll to perform an eccentric orbiting movement;

a bearing member which is provided inside the housing and supports the drive shaft;

an annular thrust plate which is installed inside the housing, includes a thrust bearing surface which is in contact with a rear surface of an end plate of the orbiting scroll, and receives a thrust force acting on the orbiting scroll; and

a main balance weight which is provided in the drive shaft, is adjacent to the thrust plate in an axial direction, and cancels a centrifugal force caused by the eccentric orbiting movement of the orbiting scroll,

wherein the main balance weight includes an outer diameter decreasing portion which is provided on an end portion of the main balance weight on the thrust plate side and has an outer diameter which gradually decreases toward the thrust plate side,

wherein the thrust plate includes an inner diameter increasing portion which is provided on an inner diameter portion of the thrust plate on the main balance weight side and has an inner diameter which gradually increases toward the main balance weight side, and

wherein the outer diameter decreasing portion and the inner diameter increasing portion overlap each other in a radial direction and the axial direction.
The scroll compressor according to claim 1,
wherein the outer diameter decreasing portion has an outer conical surface shape and the inner diameter increasing portion has an inner conical surface shape which is parallel to the outer diameter decreasing portion with a gap to face the outer diameter decreasing portion.
The scroll compressor according to claim 1,
wherein the outer diameter decreasing portion has an outer stepped cylindrical surface shape having at least one step portion and the inner diameter increasing portion has an inner stepped cylindrical surface shape which meshes with the outer diameter decreasing portion with a gap.
The scroll compressor according to any one of claims 1 to 3,
wherein the main balance weight is provided to be adjacent to the bearing member in the axial direction and includes an inner peripheral overlap portion which overlaps a radially inner peripheral side of the bearing member,
wherein the inner peripheral overlap portion includes an outer diameter decreasing portion having an outer diameter which gradually decreases toward a radial bearing portion side of the bearing member in the axial direction,
wherein the bearing member includes an inner diameter increasing portion having an inner diameter which gradually increases toward the inner peripheral overlap portion side, and
wherein the outer diameter decreasing portion and the inner diameter increasing portion overlap each other in a radial direction and the axial direction.
The scroll compressor according to any one of claims 1 to 4, further comprising:
a sub-balance weight which is separated from the main balance weight,

wherein the sub-balance weight is provided on an opposite side of the main balance weight with respect to the bearing member so as to be adjacent to the bearing member in the axial direction and includes an outer peripheral overlap portion which overlaps a radially outer peripheral side of the bearing member,

wherein the outer peripheral overlap portion includes an inner diameter increasing portion having an inner diameter which gradually increases toward a fixing portion side of the bearing member in the axial direction,

wherein the bearing member includes an outer diameter decreasing portion having an outer diameter which gradually decreases toward the outer peripheral overlap portion side, and

wherein the inner diameter increasing portion and the outer diameter decreasing portion overlap each other in a radial direction and the axial direction.