EP2921706B1

EP2921706B1 - Scroll compressor

Info

Publication number: EP2921706B1
Application number: EP13862467.1A
Authority: EP
Inventors: Shunsuke Yakushiji
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2012-12-14
Filing date: 2013-09-03
Publication date: 2019-03-20
Anticipated expiration: 2033-09-03
Also published as: WO2014091641A1; EP2921706A4; JP6066708B2; JP2014118847A; EP2921706A1

Description

Technical Field

The present invention relates to a scroll compressor and in particular, to a scroll compressor in which vibration due to the movement of an Oldham ring that prevents an orbiting scroll from rotating is suppressed.

Background Art

A scroll compressor which is used in an air conditioner or a refrigeration unit is provided with a stationary scroll and an orbiting scroll each having a spiral scroll wall. Then, the orbiting scroll performs revolving motion without rotating with respect to the stationary scroll, and thus the volume of a compression chamber which is formed between the scroll walls of the two is reduced, whereby a refrigerant in the compression chamber is compressed.
In order to prevent the rotation of the orbiting scroll, an Oldham ring is interposed between the orbiting scroll and a housing which supports the orbiting scroll. The Oldham ring linearly reciprocates, as is well known, and therefore, it becomes a source of generation of an excitation force which causes the entire compressor to vibrate in a direction. In a case where a rotation speed of the compressor is low, the excitation force is also allowable. However, if it becomes high-speed rotation, vibration and noise become significant.
In other rotation system components which rotate, even if there is unbalance, by adding a balance weight to a motor which is a driving source, it is possible to make vibration due to the unbalance zero in theory. However, the excitation force by the Oldham ring cannot be offset by a conventional balance weight (or counterweight) which is provided in the rotation system component. This is because the Oldham ring linearly reciprocates, whereas the conventional balance weight rotates according to the rotation of a rotary shaft, and directions of motion of the two are different from each other.
With respect to the above, PTL 1 proposes an Oldham coupling in which a pair of ring members (a ring member which is disposed outside and a ring member which is disposed on the inside thereof) is provided and the respective ring members are disposed with the same mass and on the same plane such that a resultant force of the individual ring members which linearly reciprocate becomes the same centrifugal force as a centrifugal force which is generated by the revolution of an orbiting scroll. According to the Oldham coupling of PTL 1, vibration which is generated due to the motion of the pair of ring members is regarded as being able to be reduced by a conventional balance weight or counterweight and a reduction of noise of a device as a whole and avoidance of an adverse effect on equipment on the inside of the device are regarded as being able to be achieved.

Citation List

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 8-159050
JP H04 128583 discloses a scroll compressor.

Summary of Invention

Technical Problem

However, in the Oldham coupling of PTL 1, in the inner ring member (hereinafter sometimes referred to as a new balance weight), a guide groove is formed in the lower surface of the orbiting scroll and the new balance weight is allowed to linearly reciprocate along the guide groove. Therefore, the motion of the new balance weight follows the movement of the orbiting scroll and the new balance weight cannot move in an opposite direction to the orbiting scroll. Therefore, according to the proposal of PTL 1, a resultant force of the outer ring member and the inner ring member (the new balance weight) is applied in the same direction as a direction in which a centrifugal force of the orbiting scroll acts, and thus a tooth surface load of the orbiting scroll is increased by an amount corresponding to the resultant force, and therefore, it can become a new source of generation of vibration and noise, and uneasiness occurs in terms of the strength of the orbiting scroll itself or a stationary scroll.
The present invention has been made based on such technical problems and has an object to provide a scroll compressor which is provided with an Oldham coupling which enables a new balance weight which is used along with an Oldham ring to move in an arbitrary direction independently of the movement of an orbiting scroll.

Solution to Problem

The present invention is defined by claim 1. In the present invention, a new balance weight is moved by using an eccentric cam which is provided in an eccentric bushing of a main shaft which drives an orbiting scroll. In this case, since an angle at which the eccentric cam is provided can be arbitrarily set, it is possible to move the new balance weight (a second balance weight) in an arbitrary direction independently of the movement of the orbiting scroll.
That is, a scroll compressor according to the present invention is provided with a main shaft which is provided with an eccentric bushing and rotationally driven by a driving source, an orbiting scroll which is rotatably connected to the eccentric bushing of the main shaft, and a stationary scroll which faces the orbiting scroll, thereby forming a compression chamber which compresses a refrigerant, and has, at an end plate, a port which discharges the compressed refrigerant toward a high-pressure chamber.
The scroll compressor according to the present invention is provided with an Oldham ring which restricts movement of the orbiting scroll such that the orbiting scroll revolves without rotating with respect to the stationary scroll, a first balance weight which turns along with the eccentric bushing, an eccentric cam which turns along with the eccentric bushing, and a second balance weight which linearly reciprocates through the eccentric cam by rotational drive of the main shaft.
In the scroll compressor according to the present invention, it is preferable to cause the first balance weight to function as the eccentric cam, dispose the second balance weight in the same plane on the inside of the Oldham ring, and make a direction of reciprocating linear motion of the Oldham ring and a direction of reciprocating linear motion of the second balance weight be orthogonal to each other.
According to this scroll compressor, it is not necessary to separately prepare an eccentric cam. Further, since the second balance weight is disposed in the same plane on the inside of the Oldham ring, it is not necessary to consider balance of mass in an axial direction.
The present invention is not limited to a form of causing the first balance weight to function as the eccentric cam, and it is possible to provide an eccentric cam separately from the first balance weight. The eccentric cam can be provided at a different position of a rotation angle from the first balance weight. This suggests that it is possible to provide the eccentric cam at an arbitrary rotation angle. Also in this form, it is preferable that the second balance weight is disposed inside the Oldham ring.

Advantageous Effects of Invention

According to the present invention, the rotation of the main shaft moves the second balance weight 50 through the eccentric cam which is provided at the eccentric bushing. The eccentric cam can be mounted at an arbitrary angle on the eccentric bushing. Therefore, according to this embodiment, a direction in which the second balance weight linearly reciprocates can be arbitrarily set. For example, according to the present invention, it is possible to move the second balance weight in a direction opposite to a direction in which a centrifugal force of the orbiting scroll is generated.

Brief Description of Drawings

Fig. 1 is a vertical cross-sectional view of a scroll compressor according to an embodiment.
Fig. 2 shows an Oldham ring which is used in the scroll compressor of Fig. 1, wherein (a) is a plan view and (b) is a cross-sectional view taken along line IIb - IIb of (a) and viewed in a direction of an arrow.
Fig. 3 shows a second balance weight which is used in the scroll compressor of Fig. 1, wherein (a) is a plan view, (b) is a cross-sectional view taken along line IIIb - IIIb of (a) and viewed in a direction of an arrow, and (c) is a cross-sectional view taken along line IIIc - IIIc of (a) and viewed in a direction of an arrow.
Fig. 4 is a diagram showing an operation of the second balance weight 50 for each rotation angle of 45 degrees, wherein (a) shows an operating state at 0 degrees, (b) shows an operating state at 45 degrees, (c) shows an operating state at 90 degrees, and (d) shows an operating state at 135 degrees.
Fig. 5 follows Figs. 4(a) to 4(d), wherein (a) is 180 degrees, (b) is 225 degrees, (c) is 270 degrees, and (d) is 315 degrees.
Fig. 6 is a diagram shown by adding the Oldham ring 40 to Figs. 4(a) to 4(d), wherein (a) shows an operating state at 0 degrees, (b) shows an operating state at 45 degrees, (c) shows an operating state at 90 degrees, and (d) shows an operating state at 135 degrees.
Fig. 7 follows Figs. 6(a) to 6(d), wherein (a) is 180 degrees, (b) is 225 degrees, (c) is 270 degrees, and (d) is 315 degrees.
Fig. 8 shows a modified example of this embodiment, wherein (a) is a plan view and (b) is a cross-sectional view taken along line VIIIb - VIIIb of (a) and viewed in a direction of an arrow.

Description of Embodiments

Hereinafter, the present invention will be described in detail based on an embodiment shown in the accompanying drawings.
As shown in Fig. 1, a vertical type scroll compressor 10 is provided with a main shaft 12, an orbiting scroll 20 which rotates along with the main shaft 12, and a stationary scroll 30 fixed to a housing 11, on the inside of the housing 11.
In the scroll compressor (hereinafter referred to simply as a compressor) 10, a refrigerant is introduced from a refrigerant introduction port P1 formed in the housing 11 into the housing 11, and the refrigerant is compressed in a compression chamber which is formed between the orbiting scroll 20 and the stationary scroll 30. Then, the compressed refrigerant is discharged from a refrigerant discharge port P2 formed in the housing 11.
In the orbiting scroll 20, a spiral wrap wall 22 having a predetermined height is integrally formed at a disk-shaped end plate 21. The orbiting scroll 20 is supported on a bearing 14 of the housing 11 through an Oldham ring 40 (described later).
On the other hand, in the stationary scroll 30, a spiral wrap wall 32 facing and meshed with the wrap wall 22 of the orbiting scroll 20 is formed at an end plate 31 facing the orbiting scroll 20.
In this way, the orbiting scroll 20 and the stationary scroll 30 are combined with each other at the wrap wall 22 and the wrap wall 32. Thus, a compression chamber PR is formed between the orbiting scroll 20 and the stationary scroll 30.
In this way, the refrigerant introduced from the outer periphery sides of the orbiting scroll 20 and the stationary scroll 30 into the compression chamber PR is compressed by being sequentially sent from the outer periphery side to the inner periphery side by the revolving motion of the orbiting scroll 20 with respect to the stationary scroll 30. The refrigerant compressed in the compression chamber PR is discharged from the refrigerant discharge port P2 formed on the other end side of the housing 11 through a discharge hole 37 formed in the stationary scroll 30, a reed valve 38 provided in the discharge hole 37, and a reed valve 38 provided at an upper cover 39 provided so as to cover the stationary scroll 30.
The main shaft 12 is rotatably supported, at both end portions thereof, on the housing 11 through bearings 13 and 14. The main shaft 12 is rotationally driven by a motor 17 composed of a stator 15 fixed to the inner surface of the housing 11 and a rotor 16 fixed to the outer peripheral surface of the main shaft 12 and facing the stator 15. In addition, the main shaft 12 may have a configuration in which one end penetrates the housing 11, thereby protruding to the outside, and a driving source (not shown) such as an engine or a motor provided outside is connected to the one end of the main shaft 12, whereby the main shaft 12 is rotationally driven.
At the other end portion of the main shaft 12, an eccentric bushing 18 is formed to protrude at a position eccentric by a predetermined dimension from a central axis of the main shaft 12. On the main shaft 12 side of the orbiting scroll 20, a concave portion 23 accommodating the eccentric bushing 18 is formed. The eccentric bushing 18 is inserted into the concave portion 23 through a drive bushing (a bearing) 24, whereby the orbiting scroll 20 is rotatably retained on the eccentric bushing 18. Due to this, the orbiting scroll 20 is provided to be eccentric by a predetermined dimension with respect to the center of the main shaft 12, and thus, if the main shaft 12 rotates around its axis, the orbiting scroll 20 performs a rotation (a revolution) with a dimension eccentric with respect to the center of the main shaft 12 as a radius. The Oldham ring 40 is interposed between the orbiting scroll 20 and the main shaft 12 such that the orbiting scroll 20 does not rotate even while revolving.
The Oldham ring 40 is composed of a main body 41 having an annular shape, a pair of upper claws 43 which is provided at positions facing each other across the center of the main body 41 on the upper surface of the main body 41, and a pair of lower claws 45 which is provided on the lower surface at positions shifted by 90° in a circumferential direction of the main body 41 with respect to the upper claws 43, as shown in Fig. 2. In addition, the upper side as referred to herein means a side facing the orbiting scroll 20. The same applies to the following. Then, on the lower surface of the orbiting scroll 20, a pair of guide grooves (illustration is omitted) into which the upper claws 43 are respectively slidably fitted is formed, and on the upper surface of the bearing 14, a pair of guide grooves (illustration is omitted) into which the lower claws 45 are respectively fitted so as to be able to slide in a direction orthogonal to a slide direction of each of the upper claws 43 is formed.
Then, the upper claws 43 and the lower claws 45 are respectively fitted into the above-described guide grooves, and thus the Oldham ring 40 linearly reciprocates with respect to the bearing 14 and the orbiting scroll 20 linearly reciprocates with respect to the Oldham ring 40 in a direction orthogonal to a direction of the above-described reciprocating motion, whereby the orbiting scroll 20 revolves motion with respect to the bearing 14.
The main shaft 12 is provided with a first balance weight 25.
The first balance weight 25 is for balancing dynamic unbalance due to the revolving motion of the orbiting scroll 20 and is disposed at and fixed to the main shaft 12 symmetrically to the eccentric bushing 18, that is, so as to rotate with a phase shifted by 180 degrees with respect to the revolving motion of the orbiting scroll 20.
The first balance weight 25 is composed of a connection piece 25a which is fixed to the eccentric bushing 18 of the main shaft 12 and has an approximate fan shape in a plan view, as shown in Figs. 4(a) to 4(d), and a main body 25b which is provided to be erect upward from the connection piece 25a. In the main body 25b, a guide surface 25c of the outer periphery thereof has an arc shape in a plan view. The guide surface 25c acts on a second balance weight 50 (described next) from the inside of a cam groove 53 of the second balance weight 50, thereby being able to drive the second balance weight 50.
In the main shaft 12, a lubricating oil flow path 12a for supplying lubricating oil sucked up from an oil reservoir of a bottom portion of the housing 11 from an upper end portion of the main shaft 12 to the drive bushing 24 between the main shaft 12 and the concave portion 23 is formed.
The main shaft 12 is provided with the second balance weight 50.
The second balance weight 50 is for balancing dynamic unbalance due to the reciprocating linear motion of the Oldham ring 40 and performs reciprocating linear motion in a direction orthogonal to a movement direction of the Oldham ring 40 according to the rotation of the first balance weight 25. For this reason, the second balance weight 50 is disposed around the first balance weight 25.
The second balance weight 50 is provided with a main body 51 having a rectangular shape in a plan view, the cam groove 53 having a rounded rectangular shape and penetrating the front and the back at the center of the main body 51, and a pair of lower claws 55 which is provided at positions facing each other across the center of the main body 51 on the lower surface of the main body 51, as shown in Fig. 3. The cam groove 53 has a major axis formed along a short side direction (or a width direction) of the main body 61, and the pair of lower claws 55 is formed at both end portions of the main body 51 along a longitudinal direction (or a length direction) of the main body 51. However, the pair of lower claws 55 is slidably fitted into the pair of guide grooves which is formed in the bearing 14, and therefore, even if the second balance weight 50 is applied with a driving force, a direction of the motion thereof is restricted so as to follow the longitudinal direction of the main body 51. In addition, the guide grooves are common to the guide grooves for the Oldham ring 40.
In the second balance weight 50, the first balance weight 25 is accommodated in the cam groove 53. If the first balance weight 25 performs turning motion according to the rotation of the main shaft 12, the guide surface 25c acts on the second balance weight 50 from the inside of the cam groove 53, thereby being able to drive the second balance weight 50. The lower claws 55 are slidably fitted into the guide grooves, and therefore, the second balance weight 50 linearly reciprocates along the longitudinal direction of the main body 51.
Now, an operation of the compressor 10 having the above configuration will be described.
If the motor 17 is driven, the main shaft 12 rotates about the shaft center. Then, the eccentric bushing 18 revolves with respect to the shaft center of the main shaft 12. Accordingly, the orbiting scroll 20 with which the eccentric bushing 18 is linked revolves with respect to the stationary scroll 30 due to rotation being prevented by the Oldham ring 40. Due to this, the respective contact places between the wrap walls 22 and 32 of the scrolls 20 and 30 move toward a central portion of a scroll mechanism, and accordingly, the compression chamber PR is shrunk while spirally moving toward the central portion. Due to a series of these operations, low-pressure refrigerant gas flows from the refrigerant introduction port P1 into the compression chamber PR. Then, the refrigerant having flowed into the compression chamber PR is compressed to high pressure and reaches a central portion of the compression chamber PR, and is then discharged from the refrigerant discharge port P2 through the discharge hole 37.
Further, during this compression operation, the lubricating oil pumped up by an oil feed pump (illustration is omitted) is supplied to a radial bearing on the outer periphery side of the main shaft 12 or a thrust bearing of the upper end portion of the main shaft 12 by way of the lubricating oil flow path 12a and lubricates a sliding portion of the main shaft 12 or the orbiting scroll 20.
Next, an operation in this embodiment will be described.
The Oldham ring 40 interposed between the orbiting scroll 20 and the bearing 14 slides in a right-left direction in Fig. 1, that is, a direction (a first direction) orthogonal to the axis of the main shaft 12, according to the revolution motion of the orbiting scroll 20 described above, thereby generating an excitation force which causes the compressor 10 to vibrate in the slide direction.
On the other hand, the second balance weight 50 which is disposed inside the Oldham ring 40 slides in a direction perpendicular to the plane of Fig. 1, that is, a direction (a second direction) orthogonal to an axial direction of the main shaft 12 and the first direction, thereby generating an excitation force which causes the compressor 10 to vibrate in the slide direction. An example of an operation of the second balance weight 50 is shown in Figs. 4(a) to 4(d) and 5(a) to 5(d).
As shown in Figs. 4(a) to 4(d) and 5(a) to 5(d), if the eccentric bushing 18 turns according to the rotation of the main shaft 12, the first balance weight 25 turns with the central axis of the eccentric bushing 18 as a rotation axis. Then, the first balance weight 25 acts on the second balance weight 50 from the inside of the cam groove 53, thereby turning the second balance weight 50. That is, apparently, the second balance weight 50 performs reciprocating motion in up-down and right-left directions in the drawing with the rotation axis of the main shaft 12 as the center. However, as described above, the pair of lower claws 55 of the second balance weight 50 is fitted into the pair of guide grooves formed in the bearing 14. Therefore, with respect to the bearing 14, the movement of the second balance weight 50 is restricted to the direction in which the guide grooves are formed (the longitudinal direction of the main body 51 of the second balance weight 50). In addition, a rotation angle in Figs. 4(a) to 4(d) and 5(a) to 5(d) refers to a rotation angle of the eccentric bushing 18, and the definition of the rotation angle of 0° will be described later.
Next, operations of the second balance weight 50 and the Oldham ring 40 added to the second balance weight 50 will be described with reference to Figs. 6(a) to 6(d) and 7(a) to 7(d). In addition, in the following description, a state where the second balance weight 50 is shifted to the leftmost side and the Oldham ring 40 is shifted to the rightmost side is assumed that the rotation angle of the eccentric bushing 18 is 0°. Further, when the rotation angle is 0°, it is assumed that the centers of the second balance weight 50 and the Oldham ring 40 coincide with each other in the up-down direction in the drawing. In addition, in the description of Figs. 6 and 7, up and down and the right and left mean up and down and the right and left in the drawings.
The second balance weight 50 is displaced in a rightward direction as well as an upward direction as the eccentric bushing 18 rotates in the clockwise direction, and if the rotation angle reaches 90°, the second balance weight 50 is shifted to the uppermost side. With respect to the right-left direction, the second balance weight 50 is located at the center of a displacement stroke. The Oldham ring 40 is located at the center of a displacement stroke with respect to the right-left direction.
If the eccentric bushing 18 further rotates, the second balance weight 50 begins to be displaced in a downward direction and is displaced in the rightward direction, and if the rotation angle reaches 180°, with respect to the up-down direction, the second balance weight 50 is located at the center of the displacement stroke. The Oldham ring 40 is located on the leftmost side.
If the eccentric bushing 18 further rotates, the second balance weight 50 continues to be displaced in the downward direction and the rightward direction, and if the rotation angle reaches 270°, with respect to the up-down direction, the second balance weight 50 is located near the lowermost side. The Oldham ring 40 is located at the center of the displacement stroke in the right-left direction.
If the eccentric bushing 18 further rotates, the second balance weight 50 returns to the state in which the rotation angle is 0° (Fig. 6(a)).
As described above, the Oldham ring 40 and the second balance weight 50 which is disposed on the inside thereof linearly reciprocate in directions (respectively referred to as an X direction and a Y direction) orthogonal to each other. In addition, the Oldham ring 40 and the second balance weight 50 can be regarded as being located on the same plane and mass is set to be equal to each other. Therefore, excitation forces (referred to as F₄₀ and F₅₀) in the X direction and the Y direction by each of the Oldham ring 40 and the second balance weight 50 are the same, and the resultant force thereof acts on the entire device. Then, both of the excitation forces respectively increase and decrease according to the amount of displacement in the X direction and the amount of displacement in the Y direction of the orbiting scroll 20, and the respective excitation forces F₄₀ and F₅₀ sinusoidally change according to slide movements (the respective movements in the X direction and the Y direction) of the Oldham ring 40 and the second balance weight 50. For this reason, the resultant force of the excitation forces F₄₀ and F₅₀ acts as a certain centrifugal force.
Here, the excitation forces F₄₀ and F₅₀ by the Oldham ring 40 and the second balance weight 50 are respectively obtained by Expressions (1) and (2), and the resultant force thereof becomes (F₄₀ ²·F₅₀ ²)^1/2.
Here, m₄₀ and m₅₀ are the same, and therefore, the resultant force is expressed by Expression (3), and a certain centrifugal force based on the resultant force acts on the compressor 10. $F_{40} = m_{40} \cdot r \cdot ω^{2} \cdot sinθ$
$F$ $_{50} = m_{50} \cdot r \cdot ω^{2} \cdot cosθ$
$m \cdot r \cdot ω^{2}$

m₄₀: mass of the Oldham ring 40
m₅₀: mass of the second balance weight 50
r: revolution radius of the orbiting scroll 20
ω: angular velocity of the orbiting scroll 20
θ: rotation angle of the orbiting scroll 20

In this manner, in the compressor 10, the Oldham ring 40 and the second balance weight 50 are provided in a pair inside and outside, whereby forces which are generated according to the respective movements of the Oldham ring 40 and the second balance weight 50 can be treated in the same manner as a centrifugal force which is generated according to the rotation of the orbiting scroll 20. In addition, a direction of a centrifugal force which is generated by the resultant force occurs in the same direction as a centrifugal force which is generated by the revolution of the orbiting scroll 20.
For this reason, by appropriately setting the mass of the first balance weight 25, it is possible to offset the centrifugal force due to the movements of the Oldham ring 40 and the second balance weight 50. Typically, it is favorable if the mass of the first balance weight 25 is set to be slightly large, as compared to a case where the second balance weight 50 is not provided.
As described above, according to the compressor 10, the second balance weight 50 is provided in addition to the Oldham ring 40 and the first balance weight 25, and thus the resultant force of the Oldham ring 40 and the second balance weight 50 which linearly reciprocate becomes the same centrifugal force as the centrifugal force which is generated by the revolution of the orbiting scroll 20.
By doing so, the compressor 10 can reduce vibration according to an operation of the Oldham ring 40.
In the above, a role as an eccentric cam for driving the second balance weight 50 is given to the first balance weight 25. However, for example, as shown in Figs. 8(a) and 8(b), separately from the first balance weight 25, an eccentric cam 60 can also be provided at the eccentric bushing 18. The eccentric cam 60 has the same shape as the first balance weight 25. However, a mounting angle on the eccentric bushing 18 is different from that of the first balance weight 25. That is, the first balance weight 25 is provided in a direction opposite to the direction of the eccentricity of the orbiting scroll 20 by 180 degrees. However, the eccentric cam 60 can be mounted on the eccentric bushing 18 at an arbitrary angle with respect to the orbiting scroll 20.
For the reason as described above, the rotation of the main shaft 12 moves the second balance weight 50 through the eccentric cam (the first balance weight 25 or the eccentric cam 60) provided at the eccentric bushing 18. The eccentric cam can be mounted at an arbitrary angle on the eccentric bushing 18. Therefore, according to this embodiment, a direction in which the second balance weight 50 performs reciprocating linear motion can be arbitrarily set. For example, it is possible to move the second balance weight 50 in a direction opposite to a direction in which the centrifugal force of the orbiting scroll 20 is generated.
Further, according to this embodiment, a reciprocating movement distance (a stroke amount) of the second balance weight 50 can be arbitrarily set. That is, according to this embodiment, the stroke amount can be arbitrarily set by changing the eccentricity amount of the eccentric cam (the first balance weight 25 or the eccentric cam 60). This suggests that it is possible to arbitrarily set the mass of the second balance weight 50. In this embodiment, in order to make the inertia force of the second balance weight 50 be equivalent to the inertia force of the Oldham ring 40, it is favorable if any one of the eccentricity amount and the mass is adjusted. For example, while the mass of the second balance weight 50 is reduced, the eccentricity amount is increased, alternatively, while the mass of the second balance weight 50 is increased, the eccentricity amount is reduced, whereby it is possible to obtain a necessary inertia force.
In addition, in this embodiment, since only fitting the second balance weight 50 to the eccentric cam and also fitting the lower claws into the guide grooves of the bearing 14 is required, assemblability is good.
In addition, in the embodiment described above, the scroll compressor in which the motor 17 which is a driving source of a compression mechanism is mounted on the inside of the housing 11 has been taken as an example. However, the present invention can be applied to a scroll compressor in which a driving source of a compression mechanism is provided outside the housing 11.
In addition to this, it is possible to choose among the configurations mentioned in the above-described embodiment or appropriately change the configurations to other configurations unless it departs from the gist of the present invention.

Reference Signs List

10:: scroll compressor
11:: housing
12:: main shaft
13:: bearing
15:: stator
16:: rotor
20:: orbiting scroll
21:: end plate
25:: first balance weight
25a:: connection piece
25b:: main body
25c:: guide surface
30:: stationary scroll
31:: end plate
38:: reed valve
39:: upper cover
40:: Oldham ring
41:: main body
50:: second balance weight
51:: main body
P1:: refrigerant introduction port
P2:: refrigerant discharge port

Claims

A scroll compressor comprising:
a main shaft (12) which is provided with an eccentric bushing (18) and a driving source (17)configured to rotationally drive the main shaft (12);

an orbiting scroll (20) which is rotatably connected to the eccentric bushing (18) of the main shaft (12);

a stationary scroll (30) which faces the orbiting scroll (20), thereby forming a compression chamber configured to compress a refrigerant, and has, at an end plate, a port configured to discharge the compressed refrigerant toward a high-pressure chamber;

an Oldham ring (40) configured to restrict movement of the orbiting scroll (20) such that the orbiting scroll (20) is configured to revolve without rotating with respect to the stationary scroll (30);

a first balance weight (25) configured to turn along with the eccentric bushing (18);

an eccentric cam configured to turn along with the eccentric bushing (18); and

a second balance weight (50), the scroll compressor being characterized in that the second balance weight is provided with a main body (51) and a cam groove (53) provided at the centre of the main body (51) and is configured to linearly reciprocate through the eccentric cam by rotational drive of the main shaft (12) due to the eccentric cam configured to act on the second balance weight (50) from the inside of the cam groove (53),

so that a direction in which the second balance weight linearly reciprocates can be arbitrarily set.
The scroll compressor according to Claim 1, wherein the first balance weight (25) is configured to function as the eccentric cam,
the second balance weight (50) is disposed inside the Oldham ring (40), and
a direction of linear reciprocating motion of the Oldham ring (40) and a direction of linear reciprocating motion of the second balance weight (50) are orthogonal to each other.
The scroll compressor according to Claim 1, wherein the eccentric cam is provided at a different position of a rotation angle from the first balance weight (25), and
the second balance weight (50) is disposed inside the Oldham ring (40).
The scroll compressor according to any one of Claims 1 to 3, wherein the cam groove (53) has a major axis formed along a short side direction of the main body (51).
The scroll compressor according to any one of Claims 1 to 4, wherein the second balance weight (50) is provided with a pair of claws (55) and the pair of claws (55) is slidably fitted into grooves which are formed in a bearing (14) that supports the orbiting scroll (20).
The scroll compressor according to Claim 4 or 5, wherein the first balance weight (25) is provided with
a connection piece (25a), and
a main body (25b) which is provided to be erect from the connection piece (25a), and
an outer peripheral surface of the main body (25b) being configured to act on the second balance weight (50) from the inside of the cam groove (53).