JPS6017956B2 - Scroll compressor - Google Patents

Description

[Detailed Description of the Invention] The present invention involves meshing a pair of spiral bodies at different angles, applying circular orbital motion to one of the spiral bodies, and moving the sealed space formed between both spiral bodies toward the center of the spiral bodies. The present invention relates to a scroll compressor in which the volume is reduced and compressed fluid is discharged from the center, and in particular, it relates to an improvement in the structure of the scroll in order to increase the compression ratio.

By the way, in such a scroll compressor,
The fluid taken into the sealed space formed on the outermost side is compressed as the volume decreases as the sealed space moves toward the center as the spiral moves.

Therefore, in order to increase the uptake of the fluid to be compressed and thus the compression capacity, either the number of turns of the spiral must be increased or the wall height of the spiral must be increased. However, increasing the number of spiral turns increases the diameter of the compressor. On the other hand, when the spiral wall is made high, the rigidity of the spiral body against compressed fluid pressure becomes weaker. In view of the above points, an object of the present invention is to provide a compressor that can increase the amount of fluid to be compressed without increasing the outer diameter of the compressor, and has a spiral body with increased rigidity. .

The present invention comprises a movable scroll member having a spiral body fixed on one side of a plate, and a fixed scroll member having a spiral body fixed on one side of the plate in the same machine, by shifting the angles of both spiral bodies. The movable scroll members are overlapped while interlocking,
It is moved relative to the fixed scroll member so as to revolve on a circular orbit, and takes in fluid while forming a closed fluid pocket between both spiral wound bodies, and as the movable scroll member moves. In a scroll compressor in which the fluid pocket is moved toward the center and is accompanied by a reduction in volume to perform unidirectional continuous compression, the dimension of the fluid pocket in the ball direction is equal to the outer diameter of the spiral body. The plate surface area between the pitches of the spiral bodies of at least one of the movable scroll member and the fixed scroll member decreases in size stepwise from the outer end to the inner end along the spiral. It is formed so that it becomes higher in a step-like manner toward the terminal end, and correspondingly, the height of the spiral body of the other scroll section decreases in a step-like manner from its outer end toward its inner end. This scroll type compressor is characterized by being formed as follows.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

Referring to FIG. 1, the illustrated compressor 1 has a compressor housing 10 consisting of a front end plate 11 made of aluminum or an aluminum alloy and a cup-shaped portion 12 installed on the front end plate 11. .

The front end plate 11 is formed around a through hole 111 through which the main shaft 13 is inserted, and an annular projection 112 having the same shape as the through hole 111 is formed on the back surface.

On the other hand, the cup-shaped portion 12 is formed by drawing a steel plate or by aluminum die-casting. The cup-shaped portion 12 is fixed by ironing its opening onto the annular projection 112 of the front end plate. Note that an O-ring 14 is held at the joint to provide a seal. A disc rotor 15 is fixed inside the main shaft 13,
The disc rotor 15 is rotatably supported within the through hole 111 by a ball bearing 16 and a thrust bearing 17. The front end plate 11 also includes a sleeve 18 extending forward so as to surround the main shaft 13.
have. The sleeve 18 may be formed integrally with the front end plate 11, but here it is formed of steel separately from the front end plate, and is attached to the front surface of the front end plate 11 by screws 19. Two shaft seal assemblies are assembled on the main shaft 13 in a sleeve 18. On the outer surface of the sleeve 18, although not shown, a pulley is rotatably supported by a bearing, and an electromagnet is fixed.

On the other hand, an armature plate (not shown) is elastically supported on the end of the main shaft 13 that protrudes from the sleeve 18. That is, an electromagnetic clutch is configured by a pulley, an electromagnet, and an armature plate, which transmits the rotation of an external drive source (for example, an automobile engine) to the pulley IJ- via a belt, and by energizing the electromagnet,
By attracting the armature plate to the pulley, rotational force is transmitted to the main shaft 13. A fixed scroll member 21, a movable scroll member 22, a movable scroll drive mechanism 23, and a movable scroll rotation prevention mechanism 24 are provided within the cup-shaped portion 12 whose opening is closed by the front end plate 11.

The fixed scroll member 21 generally consists of a side plate 211 and a spiral body 212 fixed to one side of the side plate 211. A cylindrical partition wall 213 is formed on the back side of the side plate 211 so as to protrude in all axial directions. The wall thickness increases at five positions at equal angular intervals, and the fixed scroll mounting legs 214
Configure.

Each leg 214 is fixed to the cup-shaped portion 12 by a screw 25 screwed into the leg 214 from the outside of the end plate portion 121 with its tip surface in contact with the inner surface of the end plate portion 121 of the cup-shaped portion 12. ing. A seal ring 26 is provided between the head of the screw 25 and the end plate portion 121 to prevent fluid from leaking along the screw 25.
Further, a groove 215 is formed on the outer peripheral surface of the side plate 211, and a seal ring 27 is arranged in the outer circumferential surface of the side plate 211.
A seal is formed between the outer peripheral surface of the cup-shaped portion 12 and the inner surface of the cup-shaped portion 12. Therefore, the inside of the cup-shaped portion is separated by the side plate 211 of the fixed scroll member 21 into a rear chamber 28 where the partition wall 213 is present and a front chamber 29 where the spiral body 212 is disposed. A movable scroll member 22 is disposed within the chamber 29 .

Movable desk. The coil member 22 is composed of a side plate 221 and a spiral body 222 fixed to one side thereof, and the spiral body 222 is engaged with the spiral body 212 with an angular deviation of 180 degrees to form a fluid pocket between both spiral bodies. There is. The movable scroll member 22 is connected to the disc rotor 1
The driving mechanism 231 is eccentrically connected to the inner end surface of the driving mechanism 5, and is rotatably installed via a radial bearing 232. On the other hand, a fixed ring 241 is fixedly connected to the front end plate 11, and a movable ring 24 is fixed to the side plate 221 of the movable scroll 22 so as to face the fixed ring 241.
2 and balls 245 arranged in ball receiving holes 243 and 244 formed in both rings constitute a rotation prevention mechanism 24. The compressor housing 10 has a cup-shaped portion 12 provided with a suction boat 30 and a discharge boat 31 for connection to an external fluid circuit.

The fluid introduced into the chamber 29 in the housing from the suction boat 30 is taken into the fluid pocket between both scroll members 21 and 22, and is compressed by the circular orbital movement of the movable scroll 22 and moves to the center, where it moves toward the center of the fixed scroll. It is blown out from a discharge hole 216 provided in the center of the side plate 211 of the section 21 into the chamber 28, and from there flows out through the lotus hole 217 formed in the partition wall 213, through the discharge boat 31, and into the fluid circuit. 32 is a discharge valve.

In the above configuration, when the main shaft 13 is rotated by an external drive source (not shown) due to the operation of the electromagnetic clutch described above, the movable scroll portion 22 is moved into a circular orbit via the movable scroll drive mechanism 23 and the rotation prevention mechanism 24. Do some exercise.

Therefore, the fluid pocket formed between both scroll members 21 and 22 takes in the fluid introduced from the suction boat 30 and moves toward the center while decreasing in volume.
The compressed fluid is thereby discharged from the discharge hole 216 to the central chamber 281 of the discharge chamber 28 and reaches the peripheral chamber 282 from the lotus through hole 217. By the way, in this type of compressor, the wall height of the spiral portion of both the fixed and movable scroll members of the slave is constant, and the bottom plate surface is flat.

That is, the axial dimension of the fluid pocket was constant with respect to changes in crank angle. Therefore, the volume of fluid taken in was proportional to the overall wall height, and the volume tended to decrease linearly as the crank angle changed, as shown by lines a and b in FIG. 2. In addition, in the same figure, a is the height of the wall,
Here, b is the case of day 2 (day, > day 2). However, if you think about it basically, the intake volume of the spiral is determined by the confined space formed at the outermost periphery, and has nothing to do with the middle or central part.

Further, the gas reaction force received during compression is proportional to the cross-sectional area of the compression chamber (compression direction), but the pressure is higher in the middle and central chambers. Therefore, it is desirable that the heel height of this part be low. Further, it is desirable that the minimum volume of the central chamber, which is the final point of compression, be as small as possible in consideration of re-expansion loss, and for this purpose as well, it is advantageous that the wall height is low. Considering the above, it can be said that the volume at the time of gas intake is large, and it is ideal to reduce the wall height as the compression pressure increases. However, since a scroll compressor performs compression by rotating the combined spirals in a plane, a structure in which the wall height can be changed while maintaining a closed space has never been thought of until now. The present invention realizes this ideal state, which has not been considered in the past, through a clever combination of the spiral wall height and the bottom height between the spiral pitches. Hereinafter, the structure of the scroll according to the present invention will be explained in detail.

An example of the spiral shape of the present invention is shown in cross-section in FIG.

In the illustrated example, the wall height is changed to two levels, but it may be changed to any number of levels. Here, a case of two-step change, which can be called basic, will be explained. Referring to FIGS. 3a and 3b, the spiral body 222 of the movable scroll member 22 has a wall height from the surface of the side plate 221 at its outer portion. This height is relatively (day, -12) due to the fact that the surface of the side plate is raised by 12 at any point proceeding inwardly from the outermost end of the spiral along the spiral. becomes high. From this part, the height of the wall is lowered by 1, at 8 points that are within the same radian at the expansion and opening angle of the spiral. That is, the height of the wall from the side plate surface at that point is 1,-12-1,=2. From this point onward, both the height of the side plate surface and the height of the wall are kept constant on the inside. Referring to FIGS. 4a and 4b, the fixed scroll member 21 also has the same shape as the movable scroll member 22, and has a nearly mirror-symmetrical shape. , day 2 correspond with the same dimensions.

Note that it is not necessary that the height change point of the side plate surface and the spiral wall height change point have a phase difference of only mrad, and as will be described later, the step shapes of both the fixed and movable scroll members are not necessarily symmetrical. Also good.

Here, a special case will be described in which the fixed and movable scroll members are completely mirror-image symmetrical with 1,=12. The state of compression when both scroll sections 21 and 22 are combined will be explained with reference to the diagrams shown in FIGS. 5A to 5D when the crank angle is changed by 90 degrees.

Figure 5a shows the end of fluid or gas uptake. In this figure, since the point in Figure 3 is set at a point that is approximately radians inward from the outermost end of the spiral, half of the opening angle is the wall height, and the other half is the wall height. , -1, -12 = day, -21 = day 2. Fifth
Figure b shows a state in which the crank is advanced by 900 degrees.

As can be seen from section K in the figure, the side edge L of the high portion of the wall and the curved end surface M section of the low section of the opposing plate surface are separated and no longer seal. However, the fluid pockets on both sides of this separated K portion form a pair of chambers of the same pressure, and no problem arises with both fluid pockets being open. In addition, this K section has the advantageous effect of equalizing the pressure in both paired fluid pockets. As is known, a scroll compressor forms a pair of symmetrical two-fluid pockets, and it is desirable from the viewpoint of force balance that both fluid pockets have the same pressure. However, it has been quite difficult to achieve equal pressure due to slight differences in the suction route or errors in shape. In the structure of the present invention, both fluid pockets are forced to equal pressure as shown in FIG. 5b.

Moreover, in FIG. 5b, a seal is maintained for each of the suction chambers and the inner fluid pockets. The state shown in FIG. 5e is a state in which the crank angle is further advanced by 9 degrees from the state shown in FIG. 5b. At this point the wall step seal is reestablished and the gas is further compressed. A state in which the crank angle is further advanced by 900 crank angles is shown in FIG. 5d.

Here, most of the wall height days, 11, 112 = days, 12
1=day 2, that is, a fluid pocket with a small dimension in the thin direction is formed when the wall height decreases L.
If the crank angle increases further, compression will occur only in the fluid pocket, which has a small axial dimension and is formed only by the portion with a low wall height. The characteristics of the crank angle versus volume change of the present invention are shown in FIG.

The characteristics of the embodiment of the present invention exhibit a curved line change as shown by the dotted line C in the same figure, and change to a linear change from the middle. Four points are shown on the curve, point A, point B, point C, and point ○.
This corresponds to each of the states shown in FIGS. 5a to 5d. As can be seen from Fig. 2, the initial fluid pocket for gas intake is formed in the high wall portion of the spiral body, so its axial dimension is large, and therefore, the volume of the fluid pocket corresponding to the crank rotation angle is V. The rate of change of △V/AO' is steep, and as it moves from B to C to D, the proportion of the portion with low wall height as the wax winding that forms the fluid pocket increases, so the fluid pocket The dimension in the ball direction becomes smaller, and therefore the slope ΔV/Δa becomes gentler. The structure and operation of one embodiment of the present invention have been outlined above, and the advantages of the present invention can be summarized as follows.

○'The volume of the gas intake portion at the outer end of the spiral can be increased.■The height of the wall at the center of the spiral is lower, improving wall rigidity in areas of high pressure.

'3} Since the height of the center wall of the spiral is lower, machining of the spiral becomes easier.

t4, the tsuba rib is applied at the low stiffness part of the bend, the force is small at the high pressure part, and the compressive load can be smoothed against the crank angle l.

That is, torque fluctuation becomes smaller. Eye During the compression process, the paired fluid pockets retract against each other, so the pressure in both fluid pockets can be balanced.

Therefore, various problems associated with the occurrence of uneven loads are eliminated.
'6) The final compression part of the swirl, that is, the sealed space in front of the discharge valve, becomes smaller, reducing residual gas.
Power loss associated with gas re-expansion can be reduced.

'7i Since the height of the center wall of the spiral is lower, the position of the driving bearing provided on the movable spiral body in the direction of the spiral can be moved closer to the spiral wall. It is possible to reduce the generation of the moment of movement.

Therefore, the load on each bearing portion can be reduced. '8) Normally, when controlling the capacity of this type of compressor, it is practical to provide a hole in the middle of the spiral and use a valve mechanism to substantially reduce the number of turns of the spiral, and this method has already been discussed. However, if this is applied to the present invention, the capacity control ratio can be increased, and since it basically has pressure equalization characteristics, the number of check holes in the paired chambers is not two. Only one valve is required, and the opening/closing mechanism of this valve can also be simplified. The present invention has many advantages as described above.

The geometric relationship of the change in the height of the spiral wall will be explained for one example with reference to FIG. At the point of the spiral expansion/opening angle Q, draw a semicircle with radius - 10 seasons (h: orbital radius of the movable scroll, t: wall thickness) centered on the midpoint between that wall and the inner wall. A step with a depth of 1 is provided on the side plate surface. On the other hand, it is sufficient to change the height of the wall in the semicircular shape of half-ridge 2 with a depth of 1 from the center of the spiral wall at a point where the extension angle is returned by a medium radian from this point. This is a two-stage type in which the fixed and movable scroll members are symmetrical. From the standpoint of mechanical balance, this is the best. However, an asymmetric type is basically possible if unbalance is tolerated. An example is shown in FIG. This is an example in which the side plate surface 221 of the movable scroll portion 22 is made flat. In this case, if the number of spiral turns of both scroll members 21 and 22 is equal, the volume of the paired chambers will be unbalanced when gas is taken in, but by changing the number of spiral turns of the other scroll member, the intake volume can be balanced. be.
Basically, the present invention is such that the dimension of the fluid pocket formed between both scrolls in the vertical direction gradually decreases from the outer end of the spiral body to the inner end of the spiral body. This is achieved by forming a step on the side plate surface of the body and adjusting the height of the wall protrusion of the other spiral body and the amount of expansion to match the step. Furthermore, although it has been described that the height of the spiral wall can be changed in one stage, it is also possible to change the height in multiple stages as described above. An example is shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a graph showing a change curve of the compression chamber internal volume of the present invention and the conventional one, and FIG. 3 is a movable scroll portion according to the present invention. In the figures, figure a is a perspective view, figure b is a cross-sectional view taken along the line A-A', and figure 4 is a view showing the fixed scroll portion according to the present invention, figure a is a perspective view, and figure b is a cross-sectional view taken along line A-A. , Fig. 5 is a diagram explaining the compression state, a to d are diagrams showing the state at different crank angles, Fig. 6 is a diagram showing the positional relationship of the steps, and Fig. 7 is a diagram showing the three-step difference. In the example of the scroll member in the case of
FIG. 7 is a cross-sectional view of another embodiment. 1...Compressor, 13...'Main shaft, 21...
・Fixed scroll part village, 211...Side plate, 21
2... Spiral body, 22... Movable scroll member, 221... Side plate, 222... Spiral body, day,, day 2... Whirlpool wall height, 1,,12・
·····Step. Screen 1 Figure 2 Figure 3 Bag 3 Figure 4 Figure 4 Figure 5 Porridge 5 Figure 5 Crocodile 5 Figure 6 Crocodile figure 8 Figure

Claims (1)

[Claims] 1. A movable scroll member with a spiral body fixed on one side of a plate and a fixed scroll member with a spiral body similarly fixed on one side of the plate while interlocking the two spiral bodies with different angles. In addition, the movable scroll member is moved relative to the fixed scroll member so as to revolve on a circular orbit, and fluid is taken in while forming a closed fluid pocket between both spiral bodies. In a scroll type compressor, the fluid pocket is moved toward the center as the scroll member moves, and its volume is decreased to perform a unidirectional continuous compression action. The plate surface area between the pitches of the spiral body of at least one of the movable scroll member and the fixed scroll member is such that the directional dimension gradually decreases from the outer end to the inner end of the spiral body. The height of the spiral body of the other scroll member increases in a stepwise manner from the outer end to the inner end along the outer end of the scroll member. A scroll compressor is characterized by being formed in a stepwise manner.