JPS6267288A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To make variable displacement control possible, by selectively opening or closing a vent hole connected with a communication hole passing through a movable scroll member so as to communicate a compressive operating space of one operation chamber with a compressive operating space of the other operation chamber. CONSTITUTION:A teeth portion 14b of a fixed scroll member 14 is meshed with a front teeth portion 22f of a movable scroll member 22 to form a front operation chamber, while a teeth portion 18b of the member 14 is meshed with a rear portion 22r of the member 22 to form a rear operation chamber. Communication holes 42 and 44 are formed to pass through a base portion 22a of the member 22, so as to connect both the operation chambers. A cylinder 54 functioning as a vent hole is formed to intersect both the communication holes 42 and 44 and open at its outer end to a suction hole 38. When the vent hole is in a closed condition, suction of fluid is carried out, that is, the fluid sucked into the front operation chamber is fed through the communication holes 42 and 44 to the rear operation chamber, and is discharged therefrom, thus attaining a high displacement. When the vent hole is opened, the fluid is fed to one of the operation chambers, thus attaining a low displacement. Thus, the displacement control is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scroll compressor equipped with a variable displacement mechanism.

[Conventional technology]

A scroll compressor is a scroll type compressor in which a spiral scroll tooth provided on a fixed scroll member and a complementary spiral scroll tooth provided on a movable scroll member are engaged to create a compression action between these scroll teeth. form a space,
By driving a movable scroll member, the compression action is performed while reducing the compression action space.

For the purpose of increasing compression capacity, Japanese Patent Application Laid-Open No. 57-17100
No. 2 and Japanese Unexamined Patent Publication No. 57-203801 disclose scroll type compressors in which scroll teeth are provided on both end surfaces of a movable scroll member. However, in these prior art techniques, a bearing that receives a force acting in the axial direction on the movable scroll member is formed on the outer periphery of the movable scroll member, so there is a problem that the outer diameter cannot be reduced. Ta.

In Japanese Patent Application No. 59-276896, which is an earlier application of the present application, scroll teeth with different numbers of threads are provided on both sides of a movable scroll member, working chambers are provided on both sides, and the working chambers on both sides are connected through a communication hole. We have disclosed a scroll type compressor that is relatively small and has a capacity of 8 volumes. Furthermore, in this compressor, a bearing that receives the thrust force of the movable scroll member is formed inside the scroll teeth, and the compressor has been successfully reduced in size. Reducing the external dimensions of a compressor has significant advantages in its application. For example, when used as a refrigerant compressor for an automobile air conditioner, small external dimensions and high capacity are very useful.

[Problem that the invention seeks to solve]

There is also a demand for refrigerant compressors for air conditioners that are capable of capacity control. Conventionally, reciprocating type and Hoehn type compressors have been provided with a variable capacity mechanism (Ij), but scroll type compressors have not had a variable capacity mechanism. An object of the present invention is to provide a scroll compressor equipped with a variable displacement mechanism.

[Failure to solve the problem]

A scroll compressor according to the present invention includes a housing, and front and rear fixed scrolls having spiral scroll teeth having different numbers of threads disposed in the housing at intervals in the axial direction and raised in mutually opposing directions. and a spiral scroll crest disposed between the front and rear fixing members and protruding from both end surfaces of the scroll member in order to cooperate with the spiral teeth of the two identification scroll members to perform compression work, respectively. and a single drive stage for the IJ movable scroll member, thereby forming working chambers on both sides of the movable scroll member, and a compression working space of one working chamber on the other side. A communication hole is provided through the movable scroll member to communicate with the compression working space of the side working chamber, a vent hole is connected to the communication hole, and means for selectively opening or closing the vent hole is provided. It is characterized by

[For production]

When the vent hole is closed, fluid is sucked into the front and rear working chambers, and the suction fluid in the front working chamber is sent from the middle through the communication hole to the rear working chamber, and the fluid sucked from both sides is is discharged from the rear working chamber. Therefore, high capacity is achieved at this time. By opening the vent hole, the communication hole is connected to the suction space, and at least the suction fluid in the front working chamber is not sent to the rear working chamber, and the compression action is performed only in the remaining compression working space of the second stage. It will be done. At this time, low capacity is achieved.

〔Example〕

In FIG. 1, the housing of the scroll compressor according to the invention is axially connected to a front housing 1.
0 and a rear housing 12, between which a front fixed scroll member 14 is fixed with bolts 16. A rear fixed scroll member 18 is inserted into the rear housing 12 and fixed to the rear housing 12 with bolts 20. A movable scroll member 22 is further inserted into the housing between the front and rear fixed scroll members 14 and 18. These three scroll members 14, 18, and 22 have flat base portions 14a, 18a, and 2 that extend transversely within the housing, respectively.
2a, and scroll teeth protruding from their bases in the axial direction of the housing.

That is, the scroll teeth 14b of the front fixed scroll member 14 are formed toward the intermediate movable scroll member 22, and the scroll teeth 18b of the rear fixed scroll member 18 are also formed toward the intermediate movable scroll member 22. From the front and rear end surfaces of the base 22a of the intermediate movable scroll member 22, the scroll teeth 22f,
22r is formed.

As will be further explained later, the scroll teeth 14b of the front fixed scroll member 14 and the front scroll teeth 22f of the intermediate movable scroll member 22 mesh with each other to form a front working chamber, and the scroll teeth of the rear fixed scroll member 18 mesh with each other to form a front working chamber. The tooth portion 18b and the scroll member 22r on the rear side of the movable scroll member 22 mesh with each other to form a rear working chamber.

Holes are formed passing through the centers of the front housing 10 and the front fixed scroll member 14 in the axial direction, and bearings 24 and 26 are installed in these holes, respectively, and drive shafts connected to an external power source. 28 is supported. This drive shaft 28 protrudes a bearing 26, and its tip 28a is formed eccentrically from the root portion supported by the bearings 24 and 26. Therefore, the tip 28a is formed to rotate according to the amount of eccentricity as the drive shaft 28 rotates. It moves in a circular orbit with a radius. A balance weight 29 is attached to the drive shaft 28. On the other hand, a boss portion 22b is formed on the front side of the movable scroll member 22 and projects from the center of the base portion 22a.

The tip end 28a of the drive shaft 28 has a needle bearing 3
0 and is fitted into the boss portion 22b of the movable scroll member 22. Therefore, the movable scroll member 22 moves along the above-mentioned circular orbit together with the tip of the drive shaft 28. Furthermore, the base 22 of the movable scroll member 22
A plurality of circular grooves 22C are formed inwardly from the scroll tooth portion 22f on the front surface of a, and the front fixed scroll member 14 facing this also has a circular groove 14C of the same shape at a position facing the circular grooves 22c. are formed. A plurality of steel balls 32 are inserted into these plurality of circular grooves 22c and 14c.
is arranged to form a thrust bearing that receives a force applied to the movable scroll member 22 in the axial direction from the rear side to the front side, and prevents the movable scroll member 22 from rotating relative to the housing.

Therefore, as described above, the movable scroll member 22 revolves in a circular orbit together with the tip end 28a of the drive shaft 28, but since it does not rotate, its posture, that is, its angular position is constant.

A space 34 formed by the front housing 10 and the front fixed scroll member 14 includes a refrigerant gas inlet (not shown) for connection to an evaporator (not shown) of a refrigeration cycle including this compressor. ing. A seal 33 is provided to seal this space. This suction space 34 is provided between the respective bases 14a and 18a of the front and rear fixed scroll members 14 and 18 via a boat 36 formed by penetrating the peripheral portion of the front fixed scroll member 14. , 22
It communicates with a suction chamber 38 surrounding the outermost peripheral ends of f, 22r, and 18b. This suction chamber 38 is common to front and rear working chambers formed on the front and rear sides of the movable scroll member 22, respectively. On the other hand, the discharge chamber 40 is formed as a space surrounded by an annular wall 40a provided approximately at the center between the rear fixed scroll member 18 and the rear housing 12.
A discharge port 18p passes through approximately the center of the base 18a of the
It communicates with a high-pressure space in the center of a rear working chamber formed on the rear side of the movable scroll member 22, and is further connected to a condenser (not shown) of the refrigeration cycle by a discharge boat 12a. A discharge valve 41a and a valve holder 41b are arranged at the discharge port 18p. Furthermore, the base 22 of the movable scroll member 22 is used to connect the front and rear working chambers.
Two communication holes 42 that penetrate through a and extend between both end faces thereof.
, 44 are formed. Next, referring to FIGS. 2 to 7, the scroll teeth 14b and 22f.

22r, 18b and the communication holes 42, 44 will be explained in detail.

2 to 5 are cross-sectional views taken along the line ■-■ in FIG. 1, showing the relationship of the movable scroll member 22 to the front fixed scroll member 14 when the drive shaft 28 rotates 90 degrees. It shows. 6 and 7 are cross-sectional views taken along the line Vl-Vl in FIG. 1, and FIG. 7 shows a state in which the 1' live shaft 28 has been rotated 180 degrees with respect to FIG. 6. It is. FIGS. 2 to 5 show the front working chamber, and it can be seen that the scroll teeth 22f of the movable scroll member 22 are provided in a spiral shape, that is, in a range of approximately 360 degrees.

It can be seen that the posture of the movable scroll member 22 is constant, for example, as its outer end 22e and inner end 22i are located at the bottom end and the top end, respectively, in the drawing.

Scroll mountain portion 14 of front fixed scroll member 14
b is similarly formed in a spiral shape, but this is approximately 1
Only the cliffs extend. That is, its outer end is located at a position opposite to the outer end 22e of the movable scroll tooth portion 22f in the mountain diameter direction, and its inner end is configured to confine the inner end of the movable scroll tooth portion 22f.

Therefore, there are confined spaces 46, 4 which serve as compression operating spaces on the inner and outer sides of the movable scroll tooth portion 22f, respectively.
8 is formed. These confined spaces 46° 48 become smaller as the drive shaft 28 rotates, compressing the fluid.

The communication holes 42 and 44 described above are connected to the movable scroll teeth 22.
It is formed by penetrating the base 22a at the -7 position near the inner end 22i of the compressor f (near the end of the compression working space) and adjacent to its inner and outer walls. As shown in FIG. 7, the rear working chamber is formed by three spirals, and similarly, there are confined spaces 50 that serve as compressed working spaces on the inside and outside of the movable scroll peak 22r.
, 52 are formed according to the number of threads. The communication hole 4 mentioned above
2 and 44 are scroll peaks 22 for the rear working chamber.
In the middle of the spiral r, it opens inward and outward at a portion about one thread from the outer end.

Therefore, the refrigerant gas sucked from the front working chamber and the rear 11 moving chamber joins the rear working chamber halfway, and is then compressed in the rear working chamber.

Returning to FIG. 1, a cylinder 54 is formed in the plate-shaped base 22a of the movable scroll member 22 so as to intersect with the communication holes 42 and 4.1 described above. The outer end of the cylinder 54 opens 7 into the suction chamber 38 and therefore has the function of a hent hole. Its inner end passes through the port L 56 , 5B and into the pressure control chamber 60 . The port 56 extends through the base 22a of the movable scroll member 22 to the contact surface with the rear fixed scroll member 18, and the port 58 extends from the contact surface through the rear fixed scroll member 18. In order to allow the stiff ports 56, 58 to freely communicate while the movable scroll member 22 is moved relative to the rear fixed frame [1-small member], an opening 58a of the port 5B is provided.
is widened by a hole. A seal can be placed on this contact surface.

A spool 62 is inserted into the cylinder 54, a stopper 64 is fixed near the outer opening of the cylinder 54, and a spring 62 is inserted between the stopper 64 and the spool 62.
6 is placed. Figure 8 shows the spool 62 and stopper 64.
, which shows the spring 66 in detail. The spool 62 and the stopper 64 have an oval cross section, and therefore the cylinder 54 into which they are inserted also has an oval cross section. The spool 62 is divided into two parts in the longitudinal direction, and the distal end part has the above-mentioned communication hole 4.
Two holes 68 and 70 corresponding to holes 2 and 44 are provided. The remaining portion 72 is cut out flatly. A hole 74 is provided in the stopper 64.

By controlling the operating pressure supplied from the control pressure chamber 60 behind the spool 62 in the cylinder 54, the position of the spool 62 is controlled so that the holes 68 and 70 are connected to the communication holes 42 and 44.
W (FIG. 1), where the notch 72 corresponds to the communication hole 42
, 44 (FIG. 10), and the spool 6
2 passes through the communication holes 42 and 44 (Fig. 11)
can be controlled.

FIG. 9 is a block diagram for adjusting the operating pressure of the control pressure chamber 60. The high pressure of the discharge chamber 40 can be introduced into the control pressure chamber 60 via a solenoid valve 76, and the low pressure of the suction chamber 38 can be introduced through a throttle 78. . The solenoid valve 76 is energized under an electric control device that operates according to the load of the air conditioner, etc., and when the solenoid valve 76 is in the position shown in FIG. 9, high pressure is introduced from the discharge chamber 40 into the control pressure chamber 60. be done. Therefore, at this time, the compressor is in the state shown in FIG.
70, the lower end portion (vent hole) of the cylinder 54 is closed to the communicating holes 42,44.

Therefore, at this time, the compressor is at 100% capacity, fully utilizing the front and rear working chambers.

The capacity in this state is the sum of the confined spaces 46 and 48 and the confined spaces 50 and 52 in FIGS. 2 and 6.

When the solenoid valve 76 is switched, the control pressure chamber 60 is filled with the discharge chamber 40.
The high pressure in the suction chamber 38 is no longer introduced, and the low pressure in the suction chamber 38 is introduced through the throttle. In addition to maintaining these fully open and fully closed positions, the solenoid valve 76 can repeat the fully open and fully open positions in short cycles, known as duty control, thereby reducing the high pressure in the discharge chamber 40 and the suction. An intermediate pressure between the low pressure in chamber 38 can be created. At this intermediate pressure, the compressor is in the state shown in FIG. 10, and the notch 72 of the spool 62 (FIG. 8)
, 44. Here, the cutout surface of the notch 72 is opened to the communicating holes 42, 44, and the confined spaces 46, 48 of the front working chamber are connected to the communicating holes 42, 44,
Spool notch 72, cylinder 54 and stopper 6
It is communicated with the suction chamber 38 through the 60 hole 72, and the effect of the front working chamber is substantially eliminated. Notch 7
2 blocks the opening to the rear working chamber, and the compression action of the rear working chamber is carried out by the front working chamber and the communication hole 42.
, 44 would be performed as a single stage as if they were not present.

Therefore, compared to the 100% capacity, a capacity reduced to, for example, 60% is realized. In addition, the capacity in this state is 6th
In the figure, this is the capacity of the confined spaces 50 and 52.

In this embodiment, as described above, the control pressure chamber 60
Furthermore, the low pressure of the suction chamber 38 is introduced. In this case, the spool 62 is brought to a position past the communication holes 42 and 44 by the spring force of the spring 66 (first
1), the communication holes 42 and 44 are the movable scroll member 22
In this case, the communication holes 42 and 44 communicate with the suction chamber 38 via the outer end of the cylinder 54 and the hole 72 of the stopper 64. Since the holes are completely opened), not only is the front working chamber no longer active, but also the compression capacity is reduced in the rear working chamber. That is, as shown in FIGS. 6 and 7, the communication holes 42 and 44 are located inside and outside the rear working chamber at a portion about one thread from the outer end in the middle of the spiral of the scroll tooth portion 22r. Since the communication holes 42 and 44 are vented to the suction chamber 38 through the cylinder 54, there is no compression action outside the openings of the communication holes 42 and 44 in the rear working chamber. Instead, the compression action is performed only by the confined space inside the openings of the communication holes 42 and 44. Therefore, at this time, a capacity reduced to, for example, 40% is realized compared to the 100% capacity. The capacity in this state is the sum of the confined space 50a in FIG. 6 and the confined space 52a in FIG. 7.

FIG. 12 is a block diagram of another example for adjusting the pressure in the control pressure chamber 60. In this example, instead of the solenoid valve 76 in FIG. 9, the suction pressure of the compressor is adjusted according to the cooling load. A pressure control valve 82 that takes advantage of the change in pressure is used.

Inside the main body of the pressure control valve 82 is a cylinder 8 having a diameter of two stages.
4 is formed, and a spool 86 having two diameters is similarly slidably inserted into the cylinder 84. A small diameter portion 88 of a spool 86 is inserted into a small diameter portion 85 of the cylinder 84, and a ball 90 is fixed to the tip thereof. A spring 94 is inserted between the spool 86 and the stopper 92, and urges the spool 86 toward the distal end. A boat 96 is connected to the cylinder 84 at the tip of the large diameter portion of the spool 86, and this boat 96 is connected to the suction chamber 38.

A boat 98 that can be closed by a ball 90 is connected to the small diameter portion 85 of the cylinder 84, and this boat 98 is connected to the control pressure chamber 60 and the boat 10.
0 and the suction chamber 38 via the throttle 102. Further, a boat 104 is connected to the small diameter portion 85 of the cylinder 84 at the tip end of the small diameter portion 88 of the spool 86 , and this boat 104 is connected to the discharge chamber 40 .

The operation of the example shown in FIG. 12 will be explained. The suction pressure according to the cooling load to be controlled is Ps (kg/cj, abs
). Since the cooling load is large when the compressor starts operating, the suction pressure in the suction chamber 38 of the compressor is greater than P. This pressure is acting on the spool 86 from the boat 96, and overcomes the force of the spring 94, causing the spool 86 to
is moved to the right in Figure 12. Along with this, the ball 90 separates from the valve seat at the opening of the boat 98, and as a result, the boat 98 and the port 90 communicate with each other. Therefore, the high pressure of the discharge chamber 40 is introduced into the control pressure chamber 601. This achieves 100% capacity of the compressor as explained in the example of FIG.

As the operation continues, the cooling load decreases, and the pressure in the suction chamber 38 reaches P, and then becomes below Ps. Then, the spring force of the spring 94 becomes greater than the force due to suction pressure acting on the spool 86, and the spool 86 moves to the left. Therefore, the pole 90 seats on the valve seat to cut off communication between the port 98 and the boat 104, and suction pressure is introduced into the control pressure chamber 60 via the throttle 102. Therefore, the compressor changes from the state shown in FIG. 10 to the state shown in FIG. 11, with the capacity reduced. If operation with reduced capacity is continued, the cooling load will eventually increase and the suction pressure in the suction chamber 38 will become greater than P.

Then, the spool 86 moves to the right again, and the high pressure of the discharge chamber 40 is introduced into the control pressure chamber 60.

By repeating these operations, the suction pressure in the suction chamber 38 is maintained near the target value P3, and the capacity of the compressor can be adjusted according to the cooling load.

13 to 15 show a second embodiment of a scroll compressor according to the present invention. The overall structure is the first
The base 2 of the movable scroll member 22 is similar to the embodiment.
The difference from the first embodiment is that the spool inserted into the cylinder 54 intersects with the communication holes 42 and 44 passing through 2a. The spool 162 is formed as a cylindrical body as shown in FIG. 14, and therefore the cylinder 54 into which it is inserted is also formed in a cylindrical shape. On the outer periphery of the spool 162, there are two annular 1
168 and 172 are formed. Also, the stopper 164
It is also cylindrical and has a hole 174. Therefore, when high pressure is introduced into the cylinder 54, the annular grooves 168 and 170 of the spool 162 align with the communication holes 42 and 44, respectively, as shown in FIG. Similarly, 100% capacity is achieved. When low pressure is introduced into the cylinder 54, the spool 162 is at a position past the communication holes 42 and 44, as shown in FIG. % capacity is achieved. The spool 162 may be provided with a cutout similar to the cutout 72 of the spool 62 of FIG. 8 to further achieve an intermediate capacity as described in FIG. 10.

〔Effect of the invention〕

As explained above, according to the present invention, a variable capacity scroll compressor was obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a first embodiment of a scroll compressor according to the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, and FIGS. 3 to 5 are separate from each other. 6 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 7 is a sectional view similar to FIG. 6 in another operating state. 8 is an enlarged exploded perspective view of the spool, spring, and stopper in FIG. 1, FIG. 9 is a pressure control block diagram, and FIGS. 10 and 11 are the diagrams in FIG. 1 in different operating states. Partial view, Fig. 12 is a pressure control block diagram showing a variation of Fig. 9, Fig. 13 is a partial view corresponding to Fig. 1 of the second embodiment, Fig. 1411-1 shows the spool and spring in Fig. 13. and an enlarged exploded perspective view of the stopper, FIG. 15 is a view similar to FIG. 13 in another operating state. 10, 12... Housing, 14... Front fixed scroll member, 18... Rear fixed scroll member, 22... Movable scroll member, 14b, 18b, 22f, 22r - Scroll tooth portion,
42, 44...Communication hole, 54...Cylinder, 62...Spool. Figure 2 Figure 3 Figure 6, 58° Figure 7 '74 Figure 8 Figure 9 Figure 11 Figure 12 Figure 14 Figure 48 14t) 44 1b4 1bb') i 1st
Figure 5

Claims (1)

[Claims] a housing; a front and rear fixed scroll member having spiral scroll teeth having different numbers of threads disposed in the housing at intervals in the axial direction and raised in mutually opposing directions; and front and rear fixed scroll members thereof; a movable scroll member disposed between the scroll members and having spiral scroll teeth protruding from both end surfaces thereof in order to perform compression work in cooperation with the spiral scroll teeth of both fixed scroll members; a driving means for the movable scroll member, thereby forming compression stages on both sides of the movable scroll member, and converting the compression working space of the compression stage on one side into the compression working space of the compression stage on the other side. A scroll compressor characterized in that a communication hole is provided through the movable scroll member for communication, a vent hole is connected to the communication hole, and means for selectively opening or closing the vent hole is provided. .