JPH0735058A - Scroll compressor - Google Patents

Abstract

PURPOSE:To construct a scroll compressor in a small size and lessen torque variation without impairing its durability by forming the inner and outer walls of a stationary and a movable scroll with a corrected curve from an involute curve within the range where the spread angle has specific value. CONSTITUTION:From the beginning point Po, the spread angle theta is increased till the final value of spread angle, and a curve L1 is determined. At this time, the point P1 on the tangent 11 apart a distance (r) from the point Q on the basic circle Cs lies on this curve L1. This L1 forms an outer wall 22a. A normal 12 is drawn at the point P1 on the curve L1, and a point P2 is set in a position apart outward in an amount corresponding to the revolutional radius R on this normal 12, and a curve L2 is determined. Then the point L2 on the curve L2 is inverted to the position symmetrical about the origin 0, and a point P3 is set followed by determination of a curve L3. This L3 forms an inner wall 22b. The inner and outer walls 22a, 22b are formed with involute curve for one turn at the peripheral circumference, and with a corrected curve in the innermore part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type compressor (hereinafter simply referred to as "compressor"), and more particularly to improvements in a fixed scroll of a fixed scroll and a movable scroll of a movable scroll.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view of a general compressor.
This compressor has a fixed scroll 2 fixed in a housing 1 and a movable scroll 3 rotatably supported in the housing 1. Fixed scroll 2
Is composed of a fixed side plate 21 and a fixed spiral body 22 integrally formed on one surface of the fixed side plate 21. The movable scroll 3 is integrally formed with the movable side plate 31 on one surface of the movable side plate 31, and is fixed to the fixed scroll 22 by π (ra.
d) A movable spiral body 32 that meshes with a phase shift.

In this compressor, the rotation of the drive shaft 4 is changed by the eccentric bush 7 and the rotation preventing mechanism 8 to the movable scroll 3
The orbiting motion of the movable scroll 3 causes the plurality of compression chambers 5 formed between the fixed scroll 2 and the movable scroll 3 to move toward the center while sequentially reducing the volume, and thereafter, the compression chambers 5 are provided on the fixed side plate 21. From the discharge port 61 to the discharge chamber 6
Discharge compressed fluid to.

In such a compressor, generally, the inner and outer walls of the fixed and movable scrolls 22, 32 are both formed by involute curves. Here, the involute curve is r = a · θ in polar coordinates (r, θ) where the radius of the basic circle is a, the distance from the point on the basic circle is r, and the expansion angle is θ.

[0005] In addition, Japanese Patent Laid-Open No. 64-8381, Proceedings of the Academic Conference of the Japan Refrigeration Association (November 14, 1991-
15th) discloses a compressor in which both the inner and outer walls of the fixed and movable scrolls 22, 32 are formed by Archimedes curves. Here, the Archimedes curve is r = a · θ in polar coordinates (r, θ) where a is a positive constant, r is a distance from the origin, and θ is an expansion angle.

In these conventional compressors, the inner and outer walls of the fixed and movable scrolls 22, 32 are both formed by an involute curve or an Archimedes curve, so that the wall thickness is constant from the start end to the end. There is.

[0007]

However, in the above-described conventional compressor, it has been clarified that the torque fluctuation (NM) is still large, and there is a limit of reduction of power loss and vibration. In order to suppress such a large torque fluctuation, it is conceivable to increase the winding angle up to the final extension angle in order to secure a long process from the suction stage to immediately before discharge. However, in this case, the outer diameter of the compressor must be increased, or even if the outer diameter of the compressor is not increased, the wall thicknesses of the inner and outer walls of the fixed and movable scrolls must be reduced as a whole. , The miniaturization of the compressor is hindered and the durability is feared.

An object of the present invention is to reduce the torque fluctuation as much as possible without impairing the compactness and durability of the compressor.

[0009]

As a result of intensive studies, the inventors of the present invention discovered that the above problems can be solved by constructing the inner and outer walls of the fixed and movable scrolls with novel curves. Has been completed. That is, (1) In order to solve the above problems, the compressor according to claim 1 has a compression chamber between the fixed scroll and a movable scroll that is supported so as to be non-rotatable and revolvable so as to face the fixed scroll. In the scroll type compressor formed, the compression chamber is reduced in volume based on the revolution of the movable scroll,
The inner and outer walls of the fixed and movable scrolls are formed with an involute curve in a range where the expansion angle is larger than the difference between the final expansion angle and 2π (rad), and the expansion angle is the final expansion angle and 2π.
In the range smaller than the difference from (rad), the distance from the origin is smaller than the involute curve in the area where the expansion angle is small, and the distance from the origin is larger than the involute curve in the area where the expansion angle is large. A new means is adopted in which a correction coefficient is defined and a correction curve is formed by correcting the involute curve with the correction coefficient.

(2) In the compressor according to the first aspect, the inner and outer walls of the fixed and movable scrolls have a radius of a basic circle of a,
In polar coordinates (r, θ) where r is the distance from a point on the basic circle and θ is the expansion angle, the involute curve is r = a · θ, and the final expansion angle is Θ, the basic circle is The radius of a ₀ ,
When the negative correction coefficient is a ₁ , in the range of θ> θ−2π, a = a _{0 In} the range of θ ≦ θ−2π, a = a ₀ + a ₁ · sin 2π (θ / θ−2π) it can.

(3) In order to solve the above-mentioned problems, a compressor according to a third aspect of the present invention has a compression chamber between a fixed scroll and a movable scroll that faces the fixed scroll and is non-rotatably and revolvably supported. In the scroll type compressor, the compression chamber has a volume that decreases based on the revolution of the movable scroll.
In the range where the expansion angle is larger than the difference between the final expansion angle and 2π (rad), an Archimedes curve is formed, and in the range where the expansion angle is smaller than the difference between the final expansion angle and 2π (rad), the expansion angle is Of the Archimedes curve is smaller than the origin in the region of small, and the distance from the origin is larger than the Archimedes curve in the region of large expansion angle, the correction coefficient is determined, and the Archimedes curve is defined by the correction coefficient. It adopts a new means of being formed by a corrected correction curve.

(4) In the compressor according to the third aspect, the inner and outer walls of the fixed and movable scrolls are polar coordinates (r, θ) where a is a positive constant, r is a distance from the origin, and θ is an expansion angle. In the case where the Archimedes curve is r = a · θ, the final expansion angle is Θ, the positive constant of the Archimedes curve is a ₀ , and the negative correction coefficient is a ₁ , then θ> Θ-2π When a = a ₀ θ ≦ θ−2π, it can be a = a ₀ + a ₁ · sin 2π (θ / θ−2π).

[0013]

In the conventional compressor, the inner and outer walls of the fixed and movable scrolls are formed only by the involute curve or the Archimedes curve. For this reason, the distance from the origin decreases linearly as the extension angle θ decreases. On the other hand, in the compressor of the present invention, the expansion angle θ of the inner and outer walls is equal to the final expansion angle θ and 2
In the range larger than the difference between π (rad) and (θ> Θ-2π), it is formed by an involute curve or Archimedes curve, and the expansion angle θ is smaller than the difference between the final expansion angle Θ and 2π (rad) (θ ≦ In the Θ-2π) range, the correction curve is formed by correcting the involute curve or the Archimedes curve by the correction coefficient. Therefore, as the expansion angle θ decreases, the distance from the origin is larger than the involute curve or Archimedes curve in the large expansion angle area, and the distance from the origin is smaller than the involute curve or Archimedes curve in the small expansion angle area. Has been reduced. According to the test results of the present inventors, the torque fluctuation (NM) becomes small due to the volume change of the compression chamber thus determined.
This is because the length of the correction curve is longer than the length of the involute curve or Archimedes curve in the range of θ ≦ θ−2π, so that the volume of the compression chamber tends to be gradually reduced in this range as compared with the conventional case. It is believed that there is. Also,
This is because the distance from the origin is small in the region where the expansion angle is small, so the rate of change of the distance from the origin with respect to the expansion angle, that is, the slope of the correction curve is smaller than before. To be

Therefore, in this compressor, in order to reduce the torque fluctuation, it is not necessary to increase the winding angle up to the final expansion angle, and it is not necessary to reduce the thickness of the inner and outer walls as a whole. Further, in the present invention, the range of the correction curve is θ
Since it is limited to the range of ≤ Θ-2π, the outer wall is the same as the conventional one in the outermost circumference, and it is not necessary to change the outer shape.

[0015]

Embodiments Embodiments 1 and 2 embodying the present invention will be described below with reference to the drawings. (Embodiment 1) A compressor according to Embodiment 1 embodies the inventions of claims 1 and 2. This compressor is the same as the one described above except for the shapes of the fixed scroll 22 of the fixed scroll 2 and the movable scroll 32 of the movable scroll 3 in FIG. 7, and therefore the same configuration and operation will be described in detail below. Omitted.

First, the outer wall 22a and the inner wall 22b of the fixed scroll 22 will be described. That is, in general, the radius of the basic circle is a, the distance from the point on the basic circle is r, and the expansion angle is θ.
In polar coordinates (r, θ), the involute curve I is expressed by r = a · θ.

Here, as shown in FIG. 1, at the same polar coordinates (r, θ), the origin O, the basic circle Cs of radius a ₀ ,
The starting point P ₀ is taken, the final expansion angle is Θ, and the negative correction coefficient is a ₁
And Further, in the range of θ> θ−2π, a = a ₀ θ ≦ θ−2π, and in the range of a = a ₀ + a ₁ · sin 2π (θ / θ−2π). Based on this relationship, the expansion angle θ is increased from the starting point P ₀ to the final expansion angle θ (5π / 2 in the embodiment), and the curve L ₁ is obtained. At this time, for example, the point Q on the basic circle Cs
The point P ₁ on the tangent l ₁ away from the position r is located on the curve L ₁ . This curve L ₁ forms the outer wall 22a.

And the curve L₁Upper point, eg point P₁To
Normal I₂And set the normal l₂Outward for the orbital radius R above
At a point away from₂Take Curve L₁Same for other points above
The curve L₂Ask for. The starting point P₀At point C₀
Corresponds. Then, curve L₂Upper point, eg point P₂To
Invert to a position symmetrical with the origin O, and move to point P ₃Take Curve L₂
Do the same for the other points above.₃Ask for. This curve L
₃Form the inner wall 22b. Note that point C₀To point D₀But
Correspond. After this, start point P and point D₀And with a smooth curve
Connecting.

In the fixed spiral body 22 thus formed, as shown in FIG. 2, the inner and outer walls 22a, 22b are formed with an involute curve I for one circumference. Further, the inner and outer walls 22a and 22b are formed with a correction curve IF on the inner peripheral side thereof. Therefore, as shown in FIG. 3, the inner and outer walls 22a and 22b of the fixed spiral body 22 are equal to the involute curve I in the range of θ> θ−2π, and 3π / 2 <θ, as shown in FIG. ≤
The distance from the origin O is larger than the involute curve I in the region of Θ-2π, and the origin O in the region of 0 <θ ≦ 3π / 2.
The distance from is smaller than the involute curve I.

As for the inner and outer walls of the movable spiral body 32, first a circle is drawn which is in contact with the outer wall 22a of the fixed spiral body 22, and an involute curve I of a = a ₀ is obtained as the envelope of this circle by θ> Θ−2π. Connected to this involute curve I, a curve similar to the curve L ₁ is obtained from the relationship of θ ≦ Θ−2π a = a ₀ + a ₁ · sin 2π (θ / Θ−2π). This curve forms the outer wall. Then, like the fixed spiral body 22, an inner wall is formed. After that, the starting points are connected by a smooth curve, and the movable spiral body 32 is formed.

In the compressor including the fixed and movable spiral bodies 22 and 32, according to the test results of the present inventors, as shown in FIG. 4, if the correction coefficient a ₁ is negative,
Due to the volume change of the compression chamber 5, the torque fluctuation (NM) becomes small. Therefore, in this compressor, in order to reduce the torque fluctuation, it is not necessary to increase the winding angle up to the final expansion angle Θ, and it is not necessary to reduce the thickness of the inner and outer walls as a whole.

Therefore, it is understood that in this compressor, torque fluctuations can be minimized and power loss and vibration limits can be further reduced without impairing downsizing and durability. In addition, in this compressor, the fixed spiral body 22 of FIG.
As you can see, one round of the outer circumference is the involute curve I,
Fixed and movable spiral body 2 with correction curve IF on the inner peripheral side
Since the inner and outer walls of 2 and 32 are adopted, the wall thickness can be secured on the starting end side forming the high-pressure compression chamber 5 immediately before the discharge, and thereby excellent durability can be exhibited.

In this compressor, the wall thickness is constant over one circumference, but the wall thickness changes on the inner circumference side. Thus, from FIG. 4, the smaller the correction coefficient a _1, but it can reduce the torque variation, the smaller the correction coefficient a _1, because the minimum wall thickness is reduced, considering material, etc. Then, the optimum correction coefficient a ₁ is determined. However, in this compressor, even in such a case, since the fixed spiral body 22 and the movable spiral body 32 are out of phase with each other by π, the hermeticity of the compression chamber 5 is not hindered. (Embodiment 2) A compressor according to Embodiment 2 embodies the inventions of claims 3 and 4. This compressor is also the same as the above except for the shapes of the fixed scroll 22 of the fixed scroll 2 and the movable scroll 32 of the movable scroll 3 in FIG. 7, and hence the same configuration and operation will be described below. Detailed description is omitted.

First, the outer wall 22a and the inner wall 22b of the fixed scroll 22 will be described. That is, generally, in polar coordinates (r, θ) where a is a positive constant, r is a distance from the origin, and θ is an extension angle, the Archimedes curve A is represented by r = a · θ.

Here, as shown in FIG. 5, in the same polar coordinates (r, θ), the origin O is the starting point, the final expansion angle is Θ, the positive constant of the Archimedes curve A is a ₀ , and the negative correction is made. Let the coefficient be a ₁ . In the range of θ> Θ-2π, a = a ₀ θ ₁ <θ ≦ Θ-2π, a = a ₀ + a ₁ · sin 2π (θ / Θ-2π) In the range of θ <θ ₁ , the inner wall is formed. A central curve that smoothly connects to the outer wall is used. Based on this relationship, the expansion angle θ is increased from the point B ₀ (θ = θ ₁ ) to the final expansion angle θ (5π / 2 in the example), and the curve M ₁ is obtained. This curve M ₁ is the outer wall 22a
To form.

Then, the curve M₁Upper point, eg point S₁To
Normal I₂And set the normal l₂Outward for the orbital radius R above
Point S at a position away from₂Take Curve M₁Same for other points above
The curve M₂Ask for. Note that point B₀At point C₀But
Correspond. Then, curve M₂Upper point, eg point S₂The original
Invert to a point symmetrical to point O, and move to point S ₃Take Curve M₂Up
Do the same for the other points of₃Ask for. This curve M₃
Form the inner wall 22b. Note that point C₀To point D₀Is a pair
To respond. After this, origin O and point D₀And are connected with a smooth curve
To continue.

In the fixed spiral body 22 similar to that shown in FIG. 2 thus formed, the inner and outer walls 22a and 22b are formed with the Archimedes curve A for one circumference. Further, the inner and outer walls 22a and 22b are formed with a correction curve AF on the inner peripheral side thereof. Therefore, as shown in FIG. 6, the inner and outer walls 22a and 22b of the fixed spiral body 22 are equal to the Archimedes curve A in the range of θ> θ−2π and 3π / 2 <θ, as shown in FIG. ≤ Θ-2π
In the region of, the distance from the origin O is larger than that of the Archimedes curve A, and in the region of θ ₁ <θ ≦ 3π / 2, the distance from the origin O is smaller than that of the Archimedes curve A.

For the inner and outer walls of the movable spiral body 32, first, a circle that is in contact with the outer wall 22a of the fixed spiral body 22 is drawn, and as the envelope of this circle, an Archimedean curve A of a = a ₀ is obtained by θ> Θ-2π. Connected to this Archimedes curve A, a curve similar to the curve M ₁ is obtained from the relation of θ ≦ Θ−2π a = a ₀ + a ₁ · sin 2π (θ / Θ−2π). This curve forms the outer wall. Then, like the fixed spiral body 22, an inner wall is formed. After that, the origins are connected by a smooth curve, and the movable spiral body 32 is formed.

According to the test results of the present inventors, the torque fluctuation (N−M) is small even in the compressor including the fixed and movable scrolls 22 and 32. Therefore, also in this compressor, the same effect as that of the first embodiment can be obtained.

[0030]

As described above in detail, since the compressor of the present invention has the structure described in the claims, it is possible to reduce torque fluctuation as much as possible without impairing downsizing and durability. Can be made smaller. Therefore, if this compressor is adopted, the limit of power loss and vibration can be further reduced.

[Brief description of drawings]

FIG. 1 is a curve diagram showing inner and outer walls of a fixed scroll in a compressor according to a first embodiment.

FIG. 2 is a cross-sectional view showing a fixed spiral body in the compressor of the first embodiment.

FIG. 3 is a graph comparing the distance from the origin on the inner and outer walls of the fixed spiral body in the compressor of the first embodiment with the case of using an involute curve.

FIG. 4 is a graph showing a relationship between a correction coefficient and torque fluctuation in the compressor of the first embodiment.

FIG. 5 is a curve diagram showing inner and outer walls of a fixed scroll in the compressor of the second embodiment.

FIG. 6 is a graph comparing the distance from the origin with respect to the inner and outer walls of the fixed spiral body in the compressor of the second embodiment, compared with the case of using an Archimedes curve.

FIG. 7 is a vertical sectional view of a general compressor.

[Explanation of symbols]

2 ... Fixed scroll 3 ... Movable scroll 22
a ... Outer wall 22b ... Inner wall 5 ... Compression chamber θ ...
Extension angle Θ ... Final extension angle I ... Involute curve O ...
Origin a ₁ ... Correction coefficient IF, AF ... Correction curve Cs ... Basic circle A ... Archimedes curve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Kawamura 2-chome, Toyota-cho, Kariya city, Aichi stock company Toyota Industries Corp.

Claims (4)

[Claims] 1. A compression chamber is formed between a fixed scroll and a movable scroll opposed to the fixed scroll so as to be non-rotatable and revolvable, and the compression chamber has a volume based on the revolution of the movable scroll. In the scroll compressor that decreases, the inner and outer walls of the fixed and movable scrolls are formed with an involute curve in a range where the expansion angle is larger than the difference between the final expansion angle and 2π (rad), and the expansion angle is the final expansion angle. Open angle and 2π
In the range smaller than the difference from (rad), the distance from the origin is smaller than the involute curve in the area where the expansion angle is small, and the distance from the origin is larger than the involute curve in the area where the expansion angle is large. A scroll compressor, wherein a correction curve is defined and a correction curve is formed by correcting the involute curve with the correction coefficient. 2. The inner and outer walls of the fixed and movable scrolls have a radius of a basic circle, a distance from a point on the basic circle is r, and a polar angle (r, θ) where an expansion angle is θ. The curve is r = a · θ, the final expansion angle is Θ, the radius of the basic circle is a ₀ ,
If the negative correction coefficient is a ₁ , then in the range of θ> θ−2π, a = a _{0 In} the range of θ ≦ θ−2π, a = a ₀ + a ₁ · sin 2π (θ / θ−2π) The scroll type compressor according to claim 1, wherein the scroll type compressor is provided. 3. A compression chamber is formed between a fixed scroll and a movable scroll opposed to the fixed scroll so as to be non-rotatable and revolvable, and the compression chamber has a volume based on the revolution of the movable scroll. In the scroll compressor that decreases, the inner and outer walls of the fixed and movable scrolls are formed by Archimedes curves in a range where the expansion angle is larger than the difference between the final expansion angle and 2π (rad), and the expansion angle is the final expansion angle. Open angle and 2π
In the range smaller than the difference from (rad), the distance from the origin is smaller than the Archimedes curve in the region where the expansion angle is small, and the distance from the origin is larger than the Archimedes curve in the region where the expansion angle is large. The scroll type compressor is characterized in that it is formed by a correction curve in which the correction coefficient is defined and the Archimedes curve is corrected by the correction coefficient. 4. The inner and outer walls of the fixed and movable scrolls have a positive constant a, a distance from the origin r, and an expansion angle θ in polar coordinates (r, θ), where the Archimedes curve is r = a. If θ, the final extension angle is Θ, the positive constant of the Archimedes curve is a ₀ , and the negative correction coefficient is a ₁ , then θ> Θ-2π a = a ₀ θ ≦ Θ-2π when _{a = a 0 + a 1 ·} sin2π (θ / Θ-2π) scroll compressor according to claim 3, characterized in that the.