JPH04292593A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To miniaturize the whole compressor, and, at the same time, realize weight reduction too, maintaining the strength of a starting end part from a viewpoint of durability. CONSTITUTION:In fixed and movable scrolls 2, 3, external wall curves SG1, MG1 consist of curves whose arcuation is reduced from an involute curve I1 in response to the increase of an involute angler theta, internal wall curves SG3, MG3 consist of curves based on these external wall curves SM1, MG1, and starting end parts 22a, 32a are constituted connecting external wall curves SG1, MG1 and internal wall curves SG3, MG3 including parts of external wall curves SG1, Mg1 and parts of internal wall curves SG3, MG3.

Description

[Detailed description of the invention]

0001

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

0002

2. Description of the Related Art FIG. 10 shows a sectional view of a general compressor. This compressor has a fixed scroll 2 fixed within a housing 1 and a movable scroll 3 supported within the housing 1 so as to be freely rotatable. The fixed scroll 2 includes 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 a movable side plate 31 on one surface of the movable side plate 31, and is mutually π(r) with the fixed spiral body 22.
ad) A movable spiral body 32 that meshes with each other out of phase. The inner and outer walls of the fixed spiral body 22 and the movable spiral body 32 in a typical compressor are both formed by involute curves so as to be in constant contact with each other, and have a constant wall thickness from the starting end to the ending end.

In this compressor, the rotation of the drive shaft 4 is controlled by the movable scroll 3 via the eccentric bush 7 and the rotation prevention mechanism 8.
Due to the orbital movement of the movable scroll 3, the plurality of compression chambers 5 formed between the movable scroll 3 and the fixed scroll 2 move toward the center while sequentially decreasing their volume, and then the compression chambers 5 formed on the fixed side plate 21 move toward the center. From the discharge port 61 to the discharge chamber 6
Discharge compressed fluid to.

By the way, one way to reduce the weight of a compressor is to reduce its wall thickness. From this point of view, Japanese Patent Laid-Open No. 60-98186 discloses a compressor in which the wall thickness of the movable spiral body 32 is gradually thinned toward the terminal end. In this compressor, the outer wall curve of the movable spiral body 32 is formed by an involute curve formed by a base circle with a predetermined diameter, and the inner wall curve of the movable spiral body 32 is formed by an involute curve formed by a base circle with a smaller diameter than this base circle. By forming the movable spiral body 32, the wall thickness of the movable spiral body 32 is made thin up to the terminal end.

[0005]

However, in the compressor described in the above publication, the inner and outer walls of the fixed and movable spiral bodies 22, 32 in both the scrolls 2, 3 are formed by involute curves as in the conventional case. If fixed and movable spiral bodies 22 and 32 of a predetermined length are to be obtained in order to ensure a predetermined compression efficiency, each terminal end of the fixed and movable spiral bodies 22 and 32 must be located at a fixed position from the center of the compressor. As a result, it is not possible to reduce the diameter of the compressor, which leads to downsizing of the compressor.

[0006] In this compressor, both scrolls 2
, 3 to maintain contact with each other, the movable spiral body 3
The reduction in the wall thickness of 2 and the increase in the wall thickness of the fixed spiral body 22 compensate for each other. Further, in the disclosed content of this compressor, no consideration is given to the starting end, and the starting end is formed by simply and smoothly connecting the starting points of the involute curves. For this reason, if the wall thickness of the starting ends of both scrolls 2 and 3 is insufficient, the starting ends will be placed under the greatest pressure by sealing the fluid just before being discharged, and there is a risk of damage to the starting ends. However, there are problems with durability. However, both scrolls 2,
If the starting end of 3 has a wall thickness that is essential from the viewpoint of maintaining strength, the wall of the movable spiral body 32 becomes thinner toward the terminal end, but the wall thickness is fixed by the amount of decrease in the wall thickness of the movable spiral body 32. Since the wall thickness of the spiral body 22 increases, the fixed spiral body 22 similarly has an excessively thick wall thickness in the range where it meshes with the outer wall of the movable spiral body 32 as it goes from the start end to the terminal end of the wall thickness, which is essential. This makes it difficult to reduce the weight of the entire compressor.

An object of the present invention is to reduce the overall size of the compressor, and also to reduce the weight while ensuring the strength of the starting end from the viewpoint of durability.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the compressor of the present invention provides a position that is decreased from the expansion angle position on the involute curve in the direction of the expansion line as the expansion angle increases. Let the curve be the outer wall curve of the fixed and movable scroll,
The extension angle position is moved by the orbital radius of the movable scroll in the normal direction of the extension angle position on the outer wall curve or a direction similar thereto, and the moving extension angle position is taken. A point-symmetrical curve obtained by moving the position curve to a point-symmetrical position of the center point of the base circle of the involute curve is the inner wall curve of the fixed and movable scrolls, and at a certain extension/opening angle position on the starting point side on the outer wall curve. , providing a part of the outer wall curve located away from the expansion angle position on the starting point side, and moving the expansion angle position by the orbital radius in the normal direction at the expansion angle position or in a direction approximating this. The point symmetrical position on the inner wall curve where the moving extended angle position was moved to the point symmetrical position of the center point of the base circle has a position closer to the starting point than the point symmetrical position. A novel means is provided in which a part of the inner wall curve located apart from the other is provided, and a part of the outer wall curve and a part of the inner wall curve are included and connected to constitute the starting end of the fixed and movable scroll. We are hiring.

[0009] In the compressor of the present invention, when forming an inner wall curve based on an outer wall curve, the normal direction or a direction approximating this is directed outward, and an outer wall curve is formed based on the inner wall curve. In this case, the normal direction or a direction similar to this may be directed inward.

0010

[Operation] Geometrically, when drawing two involute curves from two starting points separated by a predetermined phase angle on the same base circle,
If you want to set the separation distance (wall thickness) between one involute curve and another involute curve, the phase angle can be calculated from the required separation distance because the phase angle and separation distance have a certain relationship. Then, each involute curve is drawn. However, for each involute curve, for example, an arbitrary expansion angle position of the outer involute curve is moved by a predetermined distance in the normal direction at that expansion angle position, and the movement expansion angle position is obtained. If the curve at the expansion/opening angle position is moved to a point-symmetrical position with respect to the center point of the base circle of the outer involute curve, the curve drawn by the moved point-symmetrical position becomes the inner involute curve. In the compressor of the present invention, paying attention to this point, the outer wall curve is formed by subtracting it from the involute curve according to the increase in the expansion/opening angle, and the outer wall curve is moved by the orbital radius of the movable scroll and a point symmetry operation is performed. It forms an inner wall curve. At this time, in addition to movement in the normal direction, movement in a direction similar to this is also allowed, so that even in such a case, the contact between the fixed and movable spiral bodies can be maintained substantially. It is from.

Therefore, in the compressor of the present invention, in the fixed and movable spiral bodies, the outer wall curve gradually moves away from the outer involute curve inward as the extension angle increases, and the inner wall curve also moves inward as the extension angle increases. Since the compressor gradually moves inward from the involute curve of the compressor and each end portion approaches the center side compared to a conventional compressor, size reduction is achieved by reducing the diameter. Note that even if the inner and outer walls are formed in this way, the inner wall is formed based on the outer wall or the outer wall is formed based on the inner wall, so the contact between the inner and outer walls is maintained, and the fixed and movable spiral bodies of a predetermined length are Maintain compression efficiency. In addition, by connecting the outer wall curve and the inner wall curve, including a part of the outer wall curve and a part of the inner wall curve, for both the fixed and movable spiral bodies, the starting end has a thicker wall thickness than the starting end of a conventional compressor. , maintain sufficient strength at the starting end. The extent to which the inner wall curve departs from the inner involute curve is smaller than the extent to which the outer wall curve departs from the outer involute curve due to the difference in expansion and opening angles. The wall thickness becomes thinner toward the end, reducing the overall weight of the compressor.

0012

Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 7, this compressor is the same as that shown in FIG. 10, except for the shapes of the fixed scroll body 22 of the fixed scroll 2 and the movable scroll body 32 of the movable scroll 3. A detailed description of the same configurations and functions will be omitted. (1) First, let us examine the geometrical characteristics of involute curves.

In FIG. 8, the involute curve I1
is the intersection point P11 (A, 0) with the x-axis on the base circle CS with radius A centered on the origin OS (0, 0) of the x-y coordinates
is created with this intersection P11 as the starting point. Here, let Q0 be the point on the base circle CS at the expansion angle θ (rad), and the involute curve I1 of the expansion angle θ
If the point above is P12 (x, y), then Aθ is Q0 P1
2, the involute curve I1 has the following relationship according to the Pythagorean theorem.

[0014] x2 +y2 =A2 +A2 θ2
……
Equation (1) Next, let l1 be the tangent (expansion line) at point Q0 on the base circle CS, let l2 be the tangent at point P12 on the involute curve I1, and let l3 be the normal line to the outside of tangent l2. . Then, a point P2 is obtained by moving the point P12 by a predetermined distance t in the direction of the normal l3.
If the coordinates of 2 are (X, Y), point P22 forms a curve I2 due to the change in expansion angle θ. Here, the normal l3
If the x component of the directional separation t is a and the y component is b,
t is expressed as in the following equation.

[0015] t2 = a2 + b2

...Equation (2) Also, X and x, and Y and y have the following relationship. X-x=a Y-y=b

...Equation (3) Therefore, by substituting Equation (3) into Equation (2), t2 = (X-x)2 + (Y-y)2 Rearranging this, X2 + Y2 = x2 + y2 + t2
+2(xa+yb) ...Formula (4) By the way, x
and y have the following relationship.

x=Acosθ+Aθsinθ
y=-Aθ cos θ+A sin θ
...Equation (5) Also, the normal l3
If the angle between and the y-axis is γ (rad), then a and b
is expressed as follows. a=tsinγ b=tcosγ
…
...Equation (6) Therefore, by substituting Equations (5) and (6) into Equation (4), X2 +Y2 =x2 +y2 +t2
+2tA{sinγ(c
osθ+θsinθ) +
cos γ (-θ cos θ + sin θ)} ...Equation (7) Now, point Q0 on the base circle CS at the extension angle θ
Let the coordinates of
x−x0 ) ...Equation (8) Here, x0 = Acos θ y0 = Asin θ, and from Equation (5) to Equation (8) becomes as follows.

dy0 /dx0 =-1/tanθ
...Equation (9) Also, if we differentiate Equation (1) with respect to x and organize it, we get
x+ydy/dx=A2 θdθ/dx
...Similar to equation (10), if we differentiate the expression for x in equation (5) with respect to θ and organize it, we get dx/
dθ=Aθcosθ
...Equation (11), therefore, Equation (10
) and (11) to find the slope dy/dx of the tangent line l2, dy/dx=(A/cosθ-x)/y
...Equation (12) Equation (12)
Substituting equation (5) into and rearranging, we get dy/
dx=tanθ
...Equation (13) Therefore,
From equations (9) and (13), it can be seen that the tangent line l1 and the tangent line l2 are orthogonal. Therefore, the tangent l1 and the normal l
3 has the same slope.

Therefore, it is possible to set cos γ = cos θ sin γ = -sin θ, and by substituting these into equation (7), we get
X2 +Y2 =x2 +y2 +t2
+2tA{-si
nθ(cosθ+θsinθ)
+cosθ(-θcosθ+sinθ)
}If we organize this, X2 +Y2 =x2 +y2 +t2
-2tAθ...Equation (14) After all, from Equations (1) and (14), X2 +Y2 =A2 +A2 θ2 +
t2 -2tAθ...Equation (15) Here, if t=Aδ, Equation (15) becomes X2 +Y2 =A2 +A2 (θ-δ
)2 ...Formula (16
) That is, the curve I2 obtained from the involute curve I1 is the involute curve I1 centered on the origin OS.
It can be seen that this is an involute curve obtained by rotationally shifting the angle δ (rad) to the right. Furthermore, the starting point P11 of the involute curve I1 has moved to point P21 (A, -t) on the involute curve I2.

As described above, if the inner and outer wall curves are to be formed by involute curves like the fixed spiral body in the conventional compressor, the involute curve I is formed from the starting point P11 as the outer wall curve with the origin OS of the base circle CS as the center.
1, and if this involute curve I1 is translated and rotated, that is, moved symmetrically around the origin OS, the resulting involute curve I
It can be seen that the inner wall curve can be obtained with 2. In addition, the involute curve I2, which is the inner wall curve, can also be obtained by creating the starting point P11 of the involute curve I1, which is the outer wall curve, from a starting point rotated to the left by an angle (π-δ) around the origin OS. Recognize.

For this reason, in a fixed spiral body in a conventional compressor, as shown in FIG. The movable scroll is moved by the revolution radius R to obtain point P22, and this point P22 is moved to a point symmetrical to the origin OS of the base circle CS to become point P3.
2, the locus of the point P32 due to changes in the expansion/opening angle θ becomes an involute curve I3, which is an inner wall curve. Note that the locus of point P22 due to changes in the expansion/opening angle θ becomes an involute curve I2. As a result, the starting point P11 of the involute curve I1 moves to the point P21 (A, -t) on the involute curve I2, and the involute curve I1 moves to the point P21 (A, -t) on the involute curve I2.
3, move to point P31 (-A, -t).

[0021] Then, by simply connecting the starting point P11 and the point P31 by a smooth curve D that does not enter the orbit of revolution, the starting end of the fixed spiral body is formed. The case where the inner and outer wall curves and the starting end of the fixed spiral body 22 are formed using the involute curves I1 and I3 has been discussed above, but when forming the inner and outer wall curves and the starting end of the movable spiral body 32, the involute curves I1 and I3 are also used. They are the same except that the phase is shifted by π. In this way, fixed and movable spirals are formed. (2) In the compressor of this embodiment, as shown in FIGS. 1 to 7, the fixed and movable spiral bodies 22 and 32 have outer walls that are different from the involute curves I1 and I3 that form the conventional fixed and movable spiral bodies. Curves SG1, MG1 and inner wall curve SG
3, MG3 is adopted, whereby the wall thicknesses of both the fixed and movable spiral bodies 22, 32 are gradually thinned toward the terminal ends. Here, for example, the outer wall curve SG1 and the inner wall curve SG3 of the fixed spiral body 22 will be considered.

In FIG. 1, the x-y coordinates are as shown in FIGS. 8 and 9.
Similarly, origin OS, base circle CS, starting point P11 (E1
1) Take involute curves I1, I2, I3, point Q0, and tangent line (expansion line) l1. Then, from the position of the expansion angle θ on the involute curve I1, the expansion line l1
Outer wall curve S
Let it be G1. If the intersection of the expansion line l1 and the outer wall curve SG1 is E12 (x, y), then (Aθ-Bθn) represents the distance Q0 E12, so the outer wall curve SG1 has the following relationship.

x2 +y2 =A2 +(Aθ−Bθn
)2 ...Formula (17)
That is, if we compare equation (17) with equation (1), Bθn
represents the distance between point P12 on the involute curve I1 and point E12 on the outer wall curve SG1, and
It can be seen that is a curve obtained by subtracting Bθn from the distance Q0 P12. Therefore, the outer wall curve SG1 gradually moves inward away from the involute curve I1 as the extension angle θ increases.

The inner wall curve SG3 corresponding to the outer wall curve SG1 expressed by equation (17) is similar to the above (1), that is, from the involute curve I1 to the involute curve I3.
It is made in the same way as when making . That is, the outer wall curve S
The expansion angle position on G1 is the normal l at that expansion angle position.
3 directions by the revolution radius R to create a curve SG2, and this curve SG2 is further moved symmetrically around the origin OS to create an inner wall curve SG3. Here, if the coordinates of point E22, which is obtained by moving point E12 in the direction of normal l3 by the revolution radius R, are (X, Y), then the change in expansion angle θ causes point E
22 forms a curve SG2. Similar to (1) above,
Assuming that the x component of the distance R in the direction of the normal l3 is a and the y component is b, then X and x and Y and y have the following relationships.

X−x=a Y−y=b

...According to equation (18), from equations (17) and (18),
Curve SG2 is expressed by the following equation (19). (X-a)2 + (Y-b)2 = A2
+(Aθ−Bθn)2

...Formula (19)
If point E22 on this curve SG2 is moved symmetrically with respect to the origin OS, and E32 is the point, E32 is the point E32.
32 forms an inner wall curve SG3. This inner wall curve SG
3 has the following relationship.

(X+a)2 +(Y+b)2 =A2
+(Aθ−Bθn)2

...Formula (20)
That is, by comparing equation (20) with equation (16), it can be seen that the curve SG3 also gradually moves away from the involute curve I3 inward as the extension angle θ increases. Note that since Bθn = 0, the starting point P11 where the extension angle θ = 0 coincides with the point E11 on the outer wall curve SG1, and this starting point P11 (E11) is P21 (E21) on the involute curve I2 (curve SG2). ) and P31 on the involute curve I3 (outer wall curve SG3)
Move to (E31). Here, a starting end 22a to be described later
In order to obtain, point P31 (E31
) to the base circle CS smoothly connecting curve SG4
Find the intersection of the base circle CS and the curve SG4 (
The starting point) is set as point P30 (E30).

In addition, in the fixed spiral body 22 of this embodiment, as shown in FIG. 2, a point Q1 with an arbitrarily small extension angle α is taken on the base circle CS, and a tangent l2 drawn to the point Q1 is connected to the outer wall curve. Let the intersection obtained by extending to SG1 be point S1. At point S1 on this outer wall curve SG1, point S1
A part of the outer wall curve SG1 located further away from the starting point P11 (E11) is connected. In other words, in this example, any other small extension angle β (β<
Take the point Q5 of α) and extend the tangent l10 drawn to the point Q5 to the outer wall curve SG1.
shall be. Then, S5 P11 of the outer wall curve SG1
The part (E11) is connected to point S1 as shown in FIG. At this time, the tangent l10 coincides with the tangent l2.

Thereafter, as shown in FIG. 2, a tangent l4 is drawn to the point S1, and a normal l5 to this tangent l4 is drawn. At the position of the revolution radius R of this normal l5, there is a curve SG2.
, and the intersection of the normal l5 and the curve SG2 is the point S2
shall be. By moving this point S2 to a point symmetrical position with the center point OS of the base circle CS, the intersection point S3 with the inner wall curve SG3 can be found. Draw a tangent l6 from point S3 to base circle CS, and define the tangent point as point Q2. A part of the inner wall curve SG3 located further away from the point S3 toward the starting point P30 (E30) is connected to this point S3. That is, in this embodiment, a tangent l11 is drawn to a point S5 on the outer wall curve SG1, and a normal l12 to this tangent l11 is drawn. This normal l1
There is a curve SG2 at a position corresponding to the revolution radius R of 2, and the intersection of the normal l12 and the curve SG2 is defined as a point S6. By moving this point S6 to a position symmetrical to the center point OS of the base circle CS, the intersection point S7 with the inner wall curve SG3 can be found. Then, from point S7 to point P31 (E
The sum of the part up to 31) and curve SG4 is connected to point S3 as shown in FIG. At this time, the tangent l13 coincides with the tangent l6.

Next, a straight line 112 is drawn from P11 (E11) on the part of the outer wall curve SG1 connected to the point S1 (S5) to the center point OS. A tangent line l13 is drawn parallel to the straight line l12 to the sum of the curve SG4 and a part of the inner wall curve SG3 connected to the point S3 (S7). Here, since the tangent line l13 touches the curve SG4, the point of contact is the point S
8. A normal line l14 is drawn from this point S8, and an arc SG5 whose radius is the revolution radius R is drawn on the normal line l14. Then, a tangent l15 is drawn from the point P11 (E11) to the arc SG5, and its point of contact is designated as S9.

[0030] Thus, point S1 on outer wall curve SG1
and the point S3 on the inner wall curve SG3 means the outer wall curve SG1
S5 P11 (E11), which is a part of , P11 (E11) S9 of tangent l15, and S9 S8 of arc SG5
, S8 P31 (E31) of the curve SG4 is connected to P31 (E31) S3 which is a part of the inner wall curve SG3. As a result, as shown in FIG. 4, the starting end 22a of the fixed spiral body 22 is made thicker than the starting end of a conventional compressor, and sufficient strength is maintained at the starting end 22a. In this way, the fixed spiral body 22 is obtained by the outer wall curve SG1, the inner wall curve SG3, and the starting end 22a.

The fixed spiral body 22 has been considered above, but as shown in FIG. 5, the outer wall curve MG1 of the movable spiral body 32
, the inner wall curve MG3 and the starting end 32a are also the same curves except that the phases are shifted by π. That is, the outer wall curve MG1 and inner wall curve MG3 of the movable spiral body 32 are the outer wall curve SG1 and the inner wall curve SG3 of the fixed spiral body 22.
is moved point-symmetrically about the origin OS, and then moved so that the center OM of the base circle CM forming the movable spiral body 32 is located on the revolution radius circle C0. Then, a straight line T1 T2 is provided on the base circle CM in parallel with the straight line Q1 Q2, and the intersection obtained by extending the tangent drawn to the point T2 to the outer wall curve MG1 is defined as a point M1. In addition, the outer wall curve MG1
A point on the inner wall curve MG3 obtained by performing parallel and point symmetrical movement of the upper point M1 is defined as a point M3. Then, point M1 on the outer wall curve MG1 and the inner wall curve MG
3. The upper point M3 is the starting end 22a of the fixed spiral body 22.
Similarly, it is connected by a part of the outer wall curve MG1, a tangent, a circular arc, a curve, and a part of the inner wall curve SG3. As a result, the starting end 32a of the movable spiral body 32 is also made thicker than the starting end of a conventional compressor, and sufficient strength is maintained at the starting end 32a. In this way, the outer wall curve MG1, the inner wall curve M
A movable spiral body 32 is obtained by G3 and the starting end 32a.

Due to the revolution of the movable scroll 3, the base circle C
The center OM of M moves on the orbit circle C0. For example, if the center OM of the base circle CM is at a revolution angle Φ (rad) from the y-axis on the orbit circle C0, and the fixed spiral body 22 and the movable spiral body 32 are in contact at points E1 and EX, , tangent l drawn from point E1 to base circle CS
7 and the base circle CS is Q3, then the straight line Q
3 OS and the straight line OS OM are at right angles. Also,
If the intersection of the tangent l8 drawn from the point EX to the base circle CM and the base circle CM is QX, then the straight line QX OM
and the straight line OS OM is also a right angle. That is, the point E1 on the outer wall curve SG1 of the fixed spiral body 22 corresponds to the point EX on the outer wall curve MG1 of the movable spiral body 32. However, if the point E1 is moved outward in the direction of the normal l9, the radius of revolution R
The point that has been moved by the same amount is E2, and the point that has been moved symmetrically with respect to the center OS of the base circle CS is a point E3 that does not coincide with the point EX. This means that the inner and outer walls of the fixed and movable spiral bodies 22 and 32 of this compressor have an outer wall curve SG1.
, MG1 and the inner wall curves SG3, MG3, and has a different shape from the involute curves I1, I3, so the slope of the normal l9 at the point E1 on the outer wall curve SG1 does not match the slope of the tangent l7.

However, both points E3 and EX are only slightly separated from each other in the tangential direction of the inner wall curve SG3 and outer wall curve MG1, and the amount of separation in the normal direction is extremely small. Therefore, the fixed and movable spiral bodies 22, 32 are connected to both points E3
, EX can be considered to be in close contact with each other. This is shown below. That is, by replacing the extension angle θ in equation (17) with the revolution angle Φ, as shown in FIG. 6, the coordinates of point EX on the outer wall curve SG3 are (X, Y),
Let EY (x, y) be a point on the involute curve when X is extended by BΦn in the direction of the tangent l8. BΦ
When the amount of n in the x-axis direction is Δx and the amount in the y-axis direction is Δy, the following relationship exists.

X=x−Δx Y=y−Δy

... Since the slope of the tangent l8 in equation (21) is -1/tanΦ similarly to equation (9), Δx and Δy have the following relationship. Δx=BΦn ・sinΦ Δ
y=-BΦn ・cosΦ
...Equation (22) Here, x and y in Equation (17) are differentiated with respect to X as X and Y, and when rearranged, we get:
A-BnΦn-1) dΦ/dX This formula is combined with formula (21),
By substituting (22), (x−BΦn s
inΦ)+(y+BΦn cosΦ)dY/dX
=(AΦ-BΦn)(A-BnΦn-1
) dΦ/dX ...Equation (23) By the way, Equation (22)
Substituting the formula for Δx in the formula for X in formula (21), differentiating this with Φ, and applying formula (11) yields dX/dΦ, so dX/dΦ=dx/dΦ−B( nΦn-1
sinΦ+Φn cosΦ)
=AΦcosΦ-B(nΦn-1 sinΦ
+Φn cosΦ)

...Equation (24) Here, for example, by substituting n=2 and Φ=π, Equation (23), (
24) and (5), dY/dX=2B/(A-Bπ)
...Equation (25) Equation (
25) represents the slope of the tangent l8 when the revolution angle Φ=π in the base circle CS. Here, for example, A=0.5(c
m), B=0.001, dY/dX=0.00
It becomes 4. On the other hand, according to equation (13), dy/dx=0. The degree of difference between the two is approximately the same at other revolution angles and positions.

That is, the normal line at point EX and point E3
Let ΔΦ be the angle formed with the normal line at , then ΔΦ≒t
anΔΦ≒dY/dX=0.004. If the revolution radius R is 1 (cm), then the point EX and the point E3 are separated by about 0.004 x 1 = 0.004 (cm) in the tangential direction, and 0.004 x 0.0 cm in the normal direction. 004=0.0
The distance will be approximately 00016 (cm). This separation distance in the normal direction of 0.000016 (cm) is within the error range for forming the inner and outer walls of the fixed and movable spiral bodies 22 and 32. Therefore, by appropriately setting the coefficient B,
The inner and outer wall curves SG1 and SG3 of the fixed spiral body 22 and the inner and outer wall curves MG1 and MG3 of the movable spiral body 32 can be substantially always in contact with each other with respect to the orbital displacement of the movable spiral body 32. Therefore, even if the inner and outer walls are formed as in this compressor, the contact between the inner and outer walls is maintained, and the fixed and movable spiral bodies 22 and 32 of a predetermined length maintain a constant compression efficiency.

In this compressor, as shown in FIG. 7, due to the revolution of the movable scroll 3, for example, the base circle CM
If the center OM of is at (0, R), the movable spiral body 32
The starting end 32a of the fixed scroll body 22 is in contact with the starting end 22a of the fixed scroll body 22, and then, as shown in FIG. The compression chamber 5 is moved toward the center to form a single compression chamber 5, and the discharge chamber 6 is opened from a discharge port 61 provided in the fixed side plate 21.
Discharge compressed fluid to.

[0037] Furthermore, the fixed spiral body 2 expressed by equation (17)
The outer wall curve SG1 of No. 2 can also be expressed as follows. L1 (θ)=Aθ−Bθn
……formula(
26) Similarly, the inner wall curve SG3 of the fixed spiral body 22 expressed by equation (20) can also be expressed as follows.

L2 (θ−π)=A(θ−π)−B(θ
-π)n...Equation (27) Then, as shown in FIG. 5, the wall thickness t of the fixed spiral body 22 is calculated by
, SG3 in the direction of the tangent l8 to the base circle CM, the wall thickness t has the following relationship. t(θ)=L1 (θ)−L2 (θ−π
) ...Equation (28) Here, if n=2, Equation (28) becomes t(θ)
=Aπ−2Bθπ+Bπ2
...Equation (29) In other words, it can be seen that the wall thickness t decreases linearly as the extension angle θ increases. Furthermore, it can be seen that even when n is 3 or more, the wall thickness decreases as θ increases.

Therefore, in this compressor, the inner wall curve S
The extent to which G3 deviates from the inner involute curve I3 is smaller than the extent to which the outer wall curve SG1 deviates from the outer involute curve I1 due to the difference in expansion angle θ. The wall thickness t becomes thinner toward the terminal end. Since this also applies to the movable spiral body 32, it can be seen that the weight of the entire compressor is reduced.

Furthermore, in the compressor of this embodiment, if the terminal end of the fixed spiral body 22 is expanded and opened at an angle θ=11π/2,
Considering the radius of the fixed spiral body 22 as the length of the expansion line when expansion angle θ = 11π/2, the outer wall curve SG1 is calculated from equation (26).
The length L1 (11π/2)=about 8.337 (cm). On the other hand, the involute curve I1 shown in FIG.
The length L0 of the expansion line is L0 (θ)=Aθ
…
...Since Equation (30) is satisfied, if the fixed spiral body is formed up to the end of the fixed spiral body at the same expansion and opening angle θ using the involute curve I1, L0 (11π/2)=about 8.635 (cm).

Therefore, in this compressor, in the fixed and movable spiral bodies 22, 32, the outer wall curves SG1, MG
1 gradually moves inward from the outer involute curve I1 as the extension angle θ increases, and similarly, the inner wall curve SG3
, MG3 also gradually moves away from the inner involute curve I3 as the expansion angle θ increases, and each terminal end approaches the center side compared to the conventional compressor, so it is possible to reduce the size by reducing the diameter. Recognize.

In the above embodiment, for example, in the fixed spiral body 22, as shown in FIGS. 2 and 3, the outer wall curve SG1
The outer wall curve SG1 from the starting point P11 (E11) to the predetermined extension angle β is adopted as a part of the inner wall curve SG3.
A curve SG4 and an inner wall curve SG3 are adopted from the starting point P30 (E30) as part of the fixed and movable spiral body 22.
, 32Circular arc SG5 of revolution radius R to avoid mutual interference
was used to correct the shape, but the starting point P11 (E11
), outer wall curve S from P30 (E30) to a certain extension angle
An intermediate portion between G1 and the inner wall curve SG3 may also be adopted. In this case, the shape may not need to be corrected depending on how the extension angle α is determined to determine the position where part of the outer wall curve SG1 and part of the inner wall curve SG3 are connected.

[0043]

As described in detail above, in the compressor of the present invention, in the fixed and movable scrolls, the outer wall curve is composed of a curve that is subtracted from the involute curve according to the increase in the expansion/opening angle. The inner wall curve is constructed from the curve based on the base curve, and the starting end is constructed by connecting the outer wall curve and the inner wall curve, including a part of the outer wall curve and a part of the inner wall curve, making the entire compressor smaller. In addition, the strength of the starting end can be ensured to improve durability, and weight reduction can also be achieved.

[Brief explanation of drawings]

FIG. 1 is a curve diagram showing an outer wall curve and an inner wall curve that form part of a fixed spiral body in a compressor according to an embodiment.

FIG. 2 is a curve diagram showing an outer wall curve, an inner wall curve, and a starting end part of a fixed spiral body in the compressor of the embodiment.

FIG. 3 is a curve diagram showing an outer wall curve, an inner wall curve, and a starting end part of a fixed spiral body in the compressor of the example.

FIG. 4 is a curve diagram showing an outer wall curve, an inner wall curve, and a starting end of a fixed spiral body in the compressor of the embodiment.

FIG. 5 is a curve diagram showing outer wall curves, inner wall curves, and starting ends of fixed and movable spiral bodies in the compressor of the embodiment.

FIG. 6 is a diagram showing an enlarged part of FIG. 3;

7 is a curve diagram showing an outer wall curve, an inner wall curve, and a starting end portion of a fixed and movable spiral body in a state where the movable scroll has revolved from the state shown in FIG. 3; FIG.

FIG. 8 is a curve diagram showing an outer wall curve forming a part of a fixed spiral body in a conventional compressor.

FIG. 9 is a curve diagram showing an outer wall curve, an inner wall curve, and a starting end of a fixed spiral body in a conventional compressor.

FIG. 10 is a longitudinal cross-sectional view of a general compressor.

[Explanation of symbols]

2...Fixed scroll
3...Movable scroll 5...Compression chamber
I1...Involute curve θ...Expansion angle
l3, l5, l9, l12...normal line SG1...outer wall curve
R…Revolution radius CS…Base circle
OS...Origin (center point)

Claims (1)

[Claims] Claim 1: A compression chamber is formed between a fixed scroll and a movable scroll that is supported so as to be non-rotatable but rotatable in opposition to the fixed scroll, and the compression chamber has a volume that increases based on the revolution of the movable scroll. In a decreasing scroll type compressor, the curve of the position that decreases from the expansion angle position on the involute curve in the direction of the expansion line as the expansion angle increases is the outer wall curve of the fixed and movable scroll, and the outer wall curve Move the extension angular position by the orbital radius of the movable scroll in the normal direction of the upper extension angular position or a direction similar to this, and take the moving extension angular position, and create a curve of the moving extension angular position. is moved to a point-symmetrical position of the center point of the base circle of the involute curve as the inner wall curve of the fixed and movable scrolls, and at a certain extension/opening angle position on the starting point side on the outer wall curve, Providing a part of the outer wall curve located further away from the opening angle position on the starting point side, and moving the expansion angle position by the orbital radius in the normal direction at the expansion angle position or in a direction approximating this. A point symmetrical position on the inner wall curve where a moving extension/opening angle position is taken and the moving extension/opening angle position is moved to a point symmetrical position of the center point of the base circle is located further away from the point symmetrical position toward the starting point side. Scroll-type compression characterized in that a part of the inner wall curve is provided, and a part of the outer wall curve and a part of the inner wall curve are included and connected to constitute the starting end of the fixed and movable scroll. Machine.