JPH0567761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scroll type fluid machine that can be used as a compressor, an expander, a motor, a pump, etc.

An example of a conventional scroll compressor is shown in FIGS. 1 to 5, and in FIG. 1, 10 is a housing, which is composed of a cup-shaped portion 12 and a front end plate 11 that closes the opening. A fixing hole 123 drilled in the opening edge of the shaped portion 12
The front end plate 11 is fastened with a fixing bolt 17 passing through a fixing hole 113 drilled in the periphery of the front end plate 11. A sleeve portion 15 protruding forward is fixed to the end surface of the front end plate 11, and a main shaft 14 passing through the sleeve portion 15 and the center of the front end plate 11 is rotatably supported via ball bearings 16, 13. ing. Built into the housing 10 are a fixed scroll member 20, a movable scroll member 21, a drive mechanism for the movable scroll member 21, and a rotation prevention mechanism 22, which will be described in detail later. The fixed scroll member 20 includes a side plate 201, a spiral body 202 implanted on one side thereof, and a leg portion 203 provided on the side opposite to the spiral body 202, and the leg portion 203 is formed into a cup-shaped portion. 12 from the outside of the cup-shaped portion 12
The bottom part 121 is fixed on the inner wall by fastening bolts passing through the bottom part 121 of the side plate 20.
1 and the inner wall surface of the cup-shaped portion 12 by sealing with an O-ring or the like.
The space inside is partitioned into a suction chamber 25 and a discharge chamber 26. Furthermore, a communication hole (not shown) is provided in the center of the side plate 201 to communicate the sealed space 23 formed between the scroll members 20 and 21 with the discharge chamber 26 .

The movable scroll member 21 has a side plate 211 and a side plate 211.
It is composed of a spiral body 212 planted on the side surface. The movable scroll member 21 is meshed with the spiral body 212 of the fixed scroll member 20 so that the spiral body 202 of the fixed scroll member 20 has an angular deviation of 180°. Then, the spiral bodies 202 and 212 come into contact at a plurality of points, and the spiral body 2
The outer ends of 02 and 212 are opposite spiral bodies 212, 2
When installed on the flank surface of 02, they contact at points A, B, C, and D, as shown in FIG. The center of revolution of the movable scroll member 21, that is, the main axis 14, perpendicular to the line connecting contact points A and B or the line connecting C and D.
Positioning holes 208 and 218 are formed in the fixed scroll member 20 and the movable scroll member 21, respectively, on an axis Y passing through the axis of A through hole 122 is formed in the bottom 121 of the cup-shaped portion 12 on the same axis as the positioning hole 208.
is drilled.

As shown in FIGS. 1 and 2, the rotation prevention mechanism 22 of the movable scroll member 21 includes a ring-shaped fixing plate 221 embedded and fixed in the inner surface of the front end plate 11, and a ring-shaped fixing plate 221 that covers the fixing race 221. a fixed ring 222 fixed to the inner surface of the movable scroll member 21; a ring-shaped fixed race 214 embedded and fixed to the outer surface of the side plate 211 of the movable scroll member 21;
4 and is fitted into a plurality of pockets 222a and 215a, which are formed in the fixed ring 222 and the movable ring 215 and penetrate in the axial direction. It consists of a ball 224. When the movable scroll member 21 is driven clockwise in FIG. 2, the movable ring 215 also moves in a circular orbit so that its center draws a circle with a radius Ror. At this time, a rotational force or moment is generated in the movable scroll member 21 in the clockwise direction in the figure due to the deviation between the point of application of the reaction force of the fluid compressed in the closed space 23 and the point of application of the driving force.
The movable scroll member 21 attempts to rotate clockwise around the center of the movable ring 215. However, the nine balls 224 in the upper part of the figure are connected to the edge of the pocket 222a of the fixed ring 222 and the movable ring 2.
The movable ring 215 cannot rotate because it is pinched by the edge of the pocket 215a of No. 15.
This prevents the movable scroll member 21 from rotating. In the illustrated state, the movable ring 215
The center of is at the far right in the figure, and the rotation stopping force distribution is
It will look like c ₁ to c ₅ . As described above, the ball 224 at the top of the figure contributes the most, and the further away from it, the smaller the ball 224, and the nine balls 224 at the bottom half of the figure do not serve to prevent rotation.
However, due to the reaction force of the compressive force, the movable scroll member 2
The pressure applied in the axial direction of 1 is thrust supported by the fixed race 221 via the movable race 214 and all the balls 224.

Next, the drive mechanism of the movable scroll member 21 will be explained. A large diameter portion 141 formed at the inner end of the main shaft 14 is supported by a pole bearing 13. Further, a drive pin (not shown) is provided on the distal end surface of the large diameter portion 141 at a position eccentric from the center thereof so as to protrude in the axial direction. On the other hand, in an annular boss 213 protruding from a side plate 211 of the movable scroll member 21, a thick disk-shaped or short shaft-shaped bush 27 is rotatably supported via a needle bearing 28. The bush 27 has a disc-shaped balance weight 271 integrally extending in the radial direction, and
The bush 27 has an eccentric hole extending in the axial direction at a position offset from the center Oc, and the drive pin is fitted into the eccentric hole and rotatably supported via a needle bearing.

When the fluid is compressed by the circular orbit movement of the movable scroll member 21, the reaction force acts on the movable scroll member 21 through the spiral body 212 in the tangential direction of the circular orbit. This force ultimately acts on the center O of the bush 27 as shown by Fd in FIG. By the way, since the bush 27 is rotatable around the drive pin, the moment of rotation around the center Od of the drive pin is expressed as a force Fd.
receive by. This moment is calculated when the angle between the direction of the force Fd and the line connecting the bush center Oc and the drive pin center Od is θ as shown in Figure 3.
It can be expressed as Fd・ε ₂ Sinθ. As a result, bush 27
The movable scroll member 21 supported above is subjected to a moment of rotation around the center Od of the drive pin, which causes the spiral body 212 to be pressed against the spiral body 202. . If this pressing force is Fp, then Fp・ε ₂ cosθ=Fd・
Since ε ₂ Sinθ, it is given by Fp=Fd・tanθ.

That is, when the bush 27 having the eccentric hole and the movable scroll member 21 are driven, a pressing force is automatically obtained at the line contact portion of both the spiral bodies 212 and 202 due to the reaction force of the fluid compression, and as a result, the closed space 23 Furthermore, as mentioned above, the center Oc of the bush 27 is secured.
is rotatable around the center Od of the drive pin, so for example, even if the thickness of the spiral body changes due to dimensional errors in the spiral bodies 202 and 212, the distance between Oc and Os will change accordingly. can. In other words, as shown in Fig. 3, the point Oc can be moved to the point Oc' or Oc'', for example, on a circular arc with radius ε ₂ centered on Od.As a result, even if there is such a dimensional error, The movable scroll member 21 can perform smooth movement.

When assembling this scroll type compressor, first, the fixed scroll member 20 and the movable scroll member 21 are temporarily fixed by screwing the bolts 17 into the fixing holes 113 and 123, and then the fixed scroll member 20 and the movable scroll member 20 are temporarily fastened together. Scroll member 21
After aligning the positioning holes 208, 218 drilled in the cup-shaped portion 12, the positioning rod 18 inserted through the through hole 122 provided in the bottom 121 of the cup-shaped portion 12 is inserted into the positioning holes 208, 218. As a result,
The movable scroll member 21 has a degree of freedom within a certain angular range around the positioning rod 18. That is, the movable scroll member 21 moves within the amount of play of the bush 27, and this bush 2
The pocket 215a of the movable ring 215 also moves by an angle equivalent to the operating angle range of 7. The rotation prevention mechanism 22, which prevents the rotational movement of the movable scroll member 21, is constantly held between the edges of the pockets 215a and 222a of the movable ring 215 and the fixed ring 222 during its operation. In order to determine the correct meshing angle position of both scroll members 20 and 21, the front end plate 11 to which the fixing ring 222 is fixed is rotated in the direction opposite to the rotational direction of the main shaft 14, so that the ball 224 engages with the fixing ring 222. It is necessary to place both scroll members 20 and 21 in the correct meshing angle position so that the pockets 222a and 215a of the movable ring 215 are sandwiched without any gap between the edges. Here, front end plate 1
Since the inner diameter of the fixing hole 113 of No. 1 is larger than the outer diameter of the bolt 17, with the bolt 17 inserted into the fixing hole 123 of the cup-shaped portion 12, the front end plate 11 is rotated in the opposite direction to the rotation direction of the main shaft 14. Rotate and move in the direction. After this, bolt 1
By tightening 7, the front end plate 11 and the cup-shaped portion 12 are joined and fixed.
As a result, the correct meshing angle position of both scroll members 20, 21 is determined. In addition,
Cup-shaped portion 12 and front end plate 11
The positioning rod 18 is removed after the screws 20 of the positioning hole 208 are inserted into the fixed scroll member 20 with the bolt 19 passing through the through hole 122 provided in the bottom 121 of the cup-shaped portion 12.
9, both positioning holes 20
8, 218 and the through hole 122 are fixed.

However, the conventional assembly method described above has the following drawbacks. That is, (1) the cup-shaped portion 12 and the front end plate 11 are temporarily fixed by screwing the bolts 17 into the plurality of fixing holes 113 and 123; (3) Rotate the front end plate 11 in the opposite direction to the direction of rotation of the main shaft 14 until it stops moving. (4) Completely fasten the cup-shaped part 12 and the front end plate 11 with the bolts 17, (5) Remove the positioning rod 18, and tighten the cup-shaped part 12 and the front end plate 1 with the bolts 19.
1 will be concluded.

By the above procedure, both scroll members 20, 21
When the meshing angle is set, initial wear will cause
Spiral body 202 of both scroll members 20, 21,
212 are in contact with each other, when the radius of rotation of the circular orbit motion of the movable scroll member 21 becomes large, even if the drive mechanism of the movable scroll member 21 follows the radius of orbit, the movable scroll member 21 relative to the fixed scroll member 20 becomes larger. The phase around the center of the drive shaft is shifted, and both spiral bodies 20
There was a problem in that a gap was formed between the flank surfaces, that is, side surfaces of No. 2, 212, and as a result, gas leaked from this gap, significantly reducing the performance of the compressor.

The present invention was invented in order to solve the above problems, and its purpose is to eliminate the gap between the flank surfaces of the spiral wound body due to initial wear of the flank surfaces, and to This system is intended to prevent gas leakage, and its gist is that a pair of fixed scroll members each having a spiral body erected on the side surface of a side plate;
The movable scroll member is meshed with the phase shifted,
While preventing the movable scroll member from rotating on its own axis via the rotation prevention mechanism, the drive mechanism causes the movable scroll member to revolve around the revolution, and the drive mechanism fits a bushing rotatable around the eccentric drive pin of the drive shaft, and engages the bushing in the drive mechanism. In a scroll type fluid machine having a variable turning radius mechanism formed by fitting the movable scroll member, the movable scroll member adjusts the phase of the movable scroll member and the fixed scroll member according to the initial wear of these spiral bodies. A scroll-type fluid machine characterized in that the scroll-type fluid machine is assembled by being shifted in the rotation direction of the scroll-type fluid machine.

Since the present invention has the above configuration,
Even if the phases of the movable scroll member and the fixed scroll member are shifted due to initial wear of the spiral body, no gap is created between the flank surfaces of the spiral body, and fluid leakage from this gap is prevented and the scroll-type fluid Can prevent functional decline.

In addition, in the initial wear of the spiral wound body described above, the contact pressure increases locally in the convex part of the flank surface caused by insufficient machining accuracy, and in the part deviated from the theoretical involute curve due to an error. Occurs due to In addition, initial wear is likely to occur in areas where the surface roughness has deteriorated due to surface treatment performed on the flank surface or in relatively soft areas.

The present invention will be explained with reference to an embodiment shown in FIG. FIG. 6 is a diagram corresponding to FIG. 4, and the same members as in the conventional one are given the same reference numerals. Reference numeral 208a denotes a positioning hole drilled in the fixed scroll member 20, and the positioning hole 208a is used to measure the initial wear of the flank surfaces of each spiral body 202, 212, aμ, which is predicted in advance, and the basis of the involute curve of each flank surface. When the radius of the circle is bmm, for reasons described later, the position is shifted in the rotational direction of the main shaft 14 from the positioning hole 218 bored in the movable scroll member 21 by an angle εrad determined by ε=1/1000・a/b. established in If a=10~40μ,
When b=5 mm, εdeg=0.1° to 0.5°. Positioning hole 208a drilled in fixed scroll member 20
, the positioning hole 218 of the movable scroll member 21
The positioning rods 18 are provided to be shifted by εrad in the rotating direction of the main shaft 14, that is, in the rotating direction of the movable scroll member 21, and the positioning rods 18 are provided in these positioning holes 208a and 218.
Fixed scroll member 20 by inserting
and the movable scroll member 21 are assembled so that the phases of the movable scroll member 21 and the movable scroll member 21 are shifted in the rotating direction of the movable scroll member 21. Therefore, even if the phase of the movable scroll member 21 is shifted due to initial wear of the flank surfaces of each spiral wound body 202, 212, no gap is created between the flank surfaces, and therefore, gas leaks from this gap. Since this does not occur, a scroll compressor with good performance can be obtained.

The reason why this gas leak does not occur will be explained below.

First, there are the following three types of relative positional deviation between the movable scroll member 21 and the fixed scroll member 20.

(a) There is no rotational deviation between the X and Y axes of the movable scroll member 21 and the fixed scroll member 20, and the axes are centered at (R).
When the radius becomes smaller (smaller than the radius Ror), the gap between each seal point → P opens as shown in Figure 7, which deteriorates the sealing performance and causes leakage.

(b) When the X and Y axes of the movable scroll member 21 rotate (counterclockwise), a gap opens at the seal point → Q as shown in Figure 8, causing leakage.

(c) When the X and Y axes of the movable scroll rotate (clockwise), a gap opens at the seal point → Q as shown in Figure 9, causing leakage.

As described above, the relative positional deviation between the movable scroll member 21 and the fixed scroll member 20 is an important factor in securing the clearance.

The movable scroll member 21 receives a force in the direction of rotation as shown in FIG. 8 with respect to the coordinate axis due to gas pressure. For this reason, the area corresponding to →P will initially wear out,
The result is the same as if the coordinates of the movable scroll were rotated by the amount of initial wear, creating a gap at the point on the →Q side and causing leakage.

Next, the functions and effects of the present invention will be explained with reference to FIGS. 10 and 11.

Fig. 10 is an enlarged view of the wear points in Fig. 8. The hatched areas are subject to a load on the contact surface due to gas pressure, which makes them more likely to wear out, and when the initial wear is over, as shown in Fig. 8. , the shaft moves by the amount lost due to wear, and a gap opens at →Q.

For this reason, the part that is considered to rotate due to initial wear is rotated in the opposite direction, as shown in FIG. 11.

Therefore, when initial wear occurs, the X and Y axes are in the correct position, the clearances on both sides of →P and →Q are maintained, and leakage can be prevented.

The important point here is that a self-aligning mechanism is provided so that the relative positions of the movable scroll member 21 and the fixed scroll member 20 are always meshed.

Next, the reason for determining the rotation angle ε (rad) will be explained.

The flank surfaces of the spiral bodies 202 and 212 form an involute curve with respect to the base circle radius b, and the coordinates of the involute curve are determined by determining the starting point of the base circle as described below.

The involute curve is the trajectory when winding the thread around the outer diameter of the base circle and unwinding the thread, so the first
As shown in Figure 2, point A is the length of A-A ₁ and A ₀ -
A is the point where the length of ₁ is equal.

Here, the length of A ₀ −A ₁ is b・ε ₀ (length of circular arc)
(ε ₀ ... in rad units).

Next, as shown in Fig. 13, when the flank surface is worn and becomes an involute curve passing through point B (the length of A-B is the wear amount), the coordinates of the involute curve are B _{The 0} point is the starting point of the involute curve.

Here, the deviation angle ε between the starting points of A ₁ and B ₀ is expressed by the following formula.

ε=A ₀ -B ₀ /b (A ₀ -B ₀ is the arc length) Here, A ₀ -B ₀ = A - B (wear length) = a (wear length).

Sideways ε=a/b, the unit of a is μ, and the unit of b is mm Then, combining the units, ε=1/1000a/b.

From the above, it can be seen that when aμ wears, the shape of the involute becomes as if the coordinates were shifted by ε.

[Brief explanation of drawings]

Figures 1 to 5 show an example of a conventional scroll compressor, with Figure 1 being a longitudinal sectional view during the assembly process, Figure 2 being a view of the rotation prevention mechanism as seen from the movable ring side, and Figure 3 is a diagram illustrating the pressing force acting on the movable scroll member, Figure 4 is a diagram showing the relative positions of the spiral body of the fixed scroll member, the spiral body of the movable scroll member, and the positioning hole, and Figure 5 is after assembly. FIG. FIG. 6 is a diagram corresponding to FIG. 4 showing one embodiment of the present invention, FIGS. 7 to 9 are diagrams showing relative positional deviations between the movable scroll member and the fixed scroll member, and FIG. Fig. 11 is an enlarged view of the wear points shown in Fig. 11. Fig. 11 is an enlarged view of the state in which initial wear has been compensated for by the present invention, Fig. 12 and Fig. 13.
The figure is a theoretical explanatory diagram for determining the angle at which the movable scroll member is rotated in advance in response to initial wear according to the present invention. Movable scroll member...21, spiral body...21
2. Fixed scroll member...20, Thin winding body...20
2.

Claims (1)

[Claims] 1 A pair of fixed scroll members each having a spiral wound body erected on the side surface of a side plate and a movable scroll member are meshed with each other with a phase shift, and the movable scroll member is prevented from rotating through an autorotation prevention mechanism. In addition, a variable turning radius mechanism is provided in which the drive mechanism is driven to revolve around the revolution, and the drive mechanism fits a bushing rotatable around an eccentric drive pin of the drive shaft, and the movable scroll member is fitted to the bushing. In a scroll type fluid machine comprising:
A scroll-type fluid machine characterized in that the movable scroll member and the fixed scroll member are assembled by shifting the phases of the movable scroll member and the fixed scroll member in the rotating direction of the movable scroll member in accordance with the initial wear of these spiral bodies.