JP2560866B2 - Scroll compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll compressor, and more particularly to improvements in a fixed scroll and a movable scroll.

[Prior Art] Fig. 13 shows a cross-sectional view of a general scroll compressor. This scroll type compressor has a fixed scroll 2 fixed in a housing 1 and a movable scroll 3 supported in the housing 1 so as to freely revolve.
The fixed scroll 2 includes a fixed side plate 21 and a fixed scroll 22 integrally formed on one surface of the fixed side plate 21. The movable scroll 3 is integrally formed on one surface of the movable side plate 31, and is fixed to the fixed scroll 22 with respect to the movable side plate 31.
And a movable spiral body 32 that meshes with a phase difference. In this scroll-type compressor, the pair of compression chambers 5 formed between the fixed scroll 2 and the fixed scroll 2 are gradually reduced in volume by the orbital motion of the movable scroll 3 via the shaft 4, and the compressed chambers 5 move toward the center to form a single unit. Then, the compressed fluid is discharged from the discharge port 61 provided in the fixed side plate 21.

By the way, in the conventional general scroll compressor,
Both the fixed spiral body 22 and the movable spiral body 32 have inner and outer walls formed by only involute curves defined by the base circle. In a scroll compressor that employs both spiral bodies with inner and outer walls formed only by involute curves,
The contact distance (pitch) of both spirals changes due to the processing error of both spirals, and thermal expansion strain concentrates on both spirals near the discharge port due to the temperature rise during operation. Easy to leak. JP 57-62
Japanese Patent Publication 988 discloses a scroll compressor capable of suitably sealing the compression chamber immediately before discharge by avoiding fluid leakage due to such a processing error of both spiral bodies in a play provided in the compression chamber which is not high pressure. ing. As shown in FIG. 14, this scroll type compressor has a structure in which a pair of compression chambers 5m and 5n are made into a single compression chamber at the moment when the spiral bodies 22 and 32 have contact points X, X to an outer peripheral end portion Y, Up to Y, the inner walls 228, 328 and the outer walls 229, 329 of both spiral bodies 22, 32 are formed to have a wall thickness thinner by a thickness α. In this scroll compressor, both spiral bodies 22, 32 have a thickness of 2α between the contact point X and the outer peripheral end portion Y.
Because of the gap, the compression chamber immediately before discharge can be suitably sealed even if there is a processing error or the like in both spiral bodies 22, 32.

[Problems to be Solved by the Invention] However, in the scroll compressor described in the above publication, as shown in FIG. 15, after the pair of compression chambers 5m and 5n are made into a single compression chamber 51, , A single compression chamber 51 pushes the discharge valve 62 (see FIG. 13) optionally provided to discharge the compressed fluid, so that the two spiral bodies 22, 32 contact the contacts X, X.
Since the central end portions Z, Z are in sliding contact with each other, both spiral bodies 22, 32
Will always be supported by two points T, T. In these two-point-supporting spirals, P = k {F (1 / r ₁ + 1 / r ₂ )} ^1/2 (where P is the surface pressure received by the spirals, k is the surface pressure of the spirals. A constant depending on the material, F: component force received by the inner and outer walls due to the compression force,
It is known that the Hertz equation of r ₁ and r ₂ : the radius of curvature of the inner and outer walls) holds. According to this Hertz's equation, if the radii of curvature r ₁ and r ₂ become smaller, the surface pressure P will become larger, so that both spiral bodies will be worn when a certain limit is exceeded. In the scroll compressor described in the above publication in which the inner and outer walls 228 and the like are formed only by the involute curve, the central end portions of both spiral bodies 22, 32 are compared with the outer peripheral end side due to the nature of the involute curve. Since it will be formed with a smaller radius of curvature,
The central ends of the spiral bodies 22, 32 are easily worn. And, in particular, by switching the inner and outer walls from the inward-routing curve to the connecting line including the inscribed arc between the outer peripheral end portion and the central end portion, the scroll type in which the strength of each central end portion of both spiral bodies is improved. In the compressor, since the radius of curvature of the connecting line including the inscribed arc is smaller than that of the involute curve, the central ends of both spirals are more easily worn.

The present invention has been made in view of the above-mentioned conventional inconvenience, and switches the inner and outer walls of both spiral bodies from an involute curve to a connecting line including an inscribed arc between the outer peripheral end and the central end. In a scroll type compressor, it is a technical problem to be solved to appropriately seal a compression chamber immediately before discharge and to reduce wear of central ends of both spiral bodies.

[Means for Solving the Problems] In the scroll compressor of the present invention, in order to solve the above problems, a fixed side plate fixed in a housing and an inner and outer wall integrally formed on one surface of the fixed side plate are provided. A fixed scroll composed of a fixed scroll formed based on an involute curve, a movable side plate rotatably supported in the housing,
A movable scroll that is integrally formed on one surface of the movable side plate, has inner and outer walls formed according to an involute curve, and that has the fixed scroll and the movable scroll that meshes with each other with a 180 ° phase shift. The fixed spiral body and the movable spiral body are configured such that an involute curve of the outer wall starts from a first extension point based on a first base point on a base circle and the inner wall forms a second base point on a second base point on the base circle.
Starting from the extension point, the inner and outer walls are formed by connecting the first extension point and the second extension point with a connecting line including at least two inscribed arcs, In a scroll compressor in which a compression chamber formed between the fixed scroll and the fixed scroll is formed to move toward the center while sequentially reducing the volume, at least one of the fixed scroll and the movable scroll has the outer wall. Is the first point near the first base point on the base circle that has advanced 360 ° in the direction of extension of the involute curve.
The first expansion based on the change point is formed so as to have a thin wall thickness up to the outer peripheral edge with the change point as a boundary, and / or the inner wall is extended from the second base point on the base circle in a direction in which the involute curve extends. A novel means is adopted in which the second extension change point based on the second change point in the vicinity of the advanced position is used as a boundary so that the outer peripheral end portion has a thin wall thickness.

It is possible to form both the spiral bodies or one of the spiral bodies to form the wall thickness to the outer peripheral end side with the extension change point as a boundary. In such a case, the inner and outer walls may be thinly formed, or only one of the inner and outer walls may be thinly formed. However, the change point of the extension of the inner wall is determined by the change point that advances 360 ° or more from the base point on the basic circle that determines the extension point of the inner wall. The extension change point of the outer wall is determined by the change point that has advanced more than 360 ° from the base point on the basic circle that determines the extension point of the outer wall.

[Operation] In the scroll compressor of the present invention, at least one of both spiral bodies is formed such that at least one of the inner and outer walls has a thin wall thickness up to the outer peripheral end with the extension change point as a boundary. At the stage where a single compression chamber discharges the compressed fluid, when both spiral bodies are in sliding contact with each other at the center end side with the extension point as a boundary, that is, both spiral bodies include an inscribed arc with a smaller radius of curvature. When making sliding contact with the connecting line, both spiral bodies are supported at three or four points. For this reason, since the force is dispersed as compared with the two-point support, both spiral bodies come into contact with each other with a small surface pressure, and the central end portions of both spiral bodies are less likely to be worn. Further, after the moment when the pair of compression chambers are made into a single compression chamber, both the spiral bodies are brought into sliding contact with each other at two points on the central end side from the extension change point, so that the compression chamber immediately before the discharge is suitable. Sealed.

Embodiments Embodiments embodying the present invention will be described below with reference to the drawings.

(Embodiment 1) The scroll type compressor of the present embodiment is a fixed scroll 2
Since the fixed scroll 22 and the movable scroll 32 of the movable scroll 3 are the same as those in FIG. 13, the detailed description of the same configurations and operations will be omitted.

As shown in FIG. 1, this scroll compressor is embodied under the following conditions.

The fixed spiral body 22 and the movable spiral body 32 have expansion change points H, which will be described later, set under the same conditions, and the spiral bodies 22 and 32 are assembled with their phases shifted by 180 °.

The involute curves of the inner and outer walls 221 and 222 of the fixed spiral body 22 and the inner and outer walls 321 and 322 of the movable spiral body 32 are determined by the basic circle O having the same radius.

The inner and outer walls 221 and 222 of the fixed spiral body 22 and the inner and outer walls 321 and 322 of the movable spiral body 32 are set at the same phase angle (θ ° = angle AOB).

Further, in the following description, the midpoint S between the origins A and B on the basic circle O is used as the reference for the expansion angle. In addition, fixed spiral body
The distance between the center of the basic circle O that determines 22 and the center of the basic circle O that determines the movable scroll 32 (the radius of the orbit of the movable scroll 3) is r ₀ .

As shown in FIG. 1, the fixed spiral body 22 and the movable spiral body 32 are both formed by outer walls 221 and 321 and inner walls 222 and 322. The involute curves of the outer walls 221 and 321 start from a midpoint S on the base circle O to a first inflection point D based on a first base point C having an inflection angle (angle SOC = β °). Inner wall 222, 3
The involute curve of 22 starts from the second inflection point F based on the second base point E which advances 180 degrees (angle COE) from the first base point C on the basic circle O. Then, the first extension point D and the second extension point F
And are connected by an inscribed arc and a tangent line. That is,
An inscribed arc having a radius r and having a center on the straight line CD is connected to the first extension point D. Further, an inscribed arc having a radius R (R = r ₀ + r) having a center on the straight line EF is connected to the second extension point F. The inscribed arcs are connected by a common tangent line.

Both the fixed spiral body 22 and the movable spiral body 32 have inner walls 222, 3
22 is the second change point G that progresses 360 ° (angle EOG) from the second base point E on the basic circle O to the direction of extension of the involute curve.
The second expansion change point H based on (the same as the second base point E) is used as a boundary so that the outer peripheral end portions 22b and 32b are thinned by a thickness α.

In this scroll compressor, as in the conventional case, as shown in FIG. 13, it is formed between the fixed scroll 2 and the shaft of the movable scroll 3, the eccentric bush 7, and the rotation preventing mechanism 8 by the revolution movement. The pair of compression chambers 5 move toward the center while sequentially reducing their volumes to move into a single compression chamber 51.
After that, the compressed fluid is discharged from the discharge port 61 provided in the fixed side plate 21. That is, when the state of the fixed spiral body 22 and the movable spiral body 32 shown in FIG. 2 is set to a crank angle of 0, both spiral bodies 22 and 32 form a pair of compression chambers 5a and 5b, and the compression immediately before discharge is performed. The chamber 51 communicates with the discharge port 61. In this state, the compression chambers 5a and 5b have a gap of thickness α, but the compression chamber 51 is sealed by two points I and J. In the state shown in FIG. 3 where the crank angle is π / 2, the compression chambers 5a and 5b also have a gap of thickness α, the compression chamber 51 is sealed by two points I and J, and a new pair of compression chambers is used. 5c and 5d are being formed. After that, in the state shown in FIG. 4 where the crank angle is π, the first and second extension points D and F of both spiral bodies 22 and 32 coincide with the contact points I and J, and the second extension change point H. , H coincide with the contacts K, L. That is, the compression chamber
5a is sealed by 2 points K and J, and compression chamber 5b is also 2 points L and I
And the compression chamber 51 is also closed by two points I and J. The compression chamber 51 shown in FIGS.
The compressed fluid is discharged from the discharge port 61 when (see FIG. 13) is pushed open. In the state shown in FIG. 5 where the crank angle is 3π / 2, the compression chambers 5a and 5b are slidably contacted at the second extension change points H and two points K and L on the side of the central end portions 22a and 32a with respect to the second extension change points H. Soon, a single compression chamber 51 is formed, and compression chambers 5c and 5d are formed.
The state of the figure is reached. After that, the states of FIGS. 2 to 5 are repeated,
The compression cycle of the pair of compression chambers ends at a crank angle of 4π.

Therefore, in this scroll type compressor,
As shown in the figure, when the compression chamber 51 is in the discharge stage,
Both the spiral bodies 22, 32 are both the second extension change points H, 2 points I, J, 2 points K, J or 2 points L, I on the central end portions 22a, 32a side.
And the compression chamber 51 and the compression chambers 5a and 5b in FIG. 4 are sealed. Therefore, even when there is a processing error or the like in both spiral bodies 22, 32, the compression chamber 51 immediately before the discharge can be suitably sealed, and the compression chambers 5a, 5b which are in the discharge stage in the next cycle are also included. It can be suitably sealed.

Further, in this scroll type compressor, both spiral bodies 22 and 32 are supported at two points I and J until just before the crank angle π. Then, from the moment of crank angle π shown in FIG.
Immediately after the crank angle 3π / 2 shown in the figure, that is, from the moment when the two spiral bodies 22, 32 are slidably contacted with each other at a connecting line including an inscribed arc having a smaller radius of curvature, the pair of compression chambers 5a, 5b is a single compression chamber.
Until the two spiral bodies 22 and 32 are slidably contacted with each other at the central end portions 22a and 32a with the first and second inflection points D and F (see FIG. 1) as boundaries, until both spiral bodies 22 and 32 are formed. 22 and 32 are supported by four points I, J, K and L. Therefore, since the force is dispersed as compared with the two-point support, the two spiral bodies 22, 32 come into contact with each other with a small surface pressure, and the central end portions 22a, 32a of the both spiral bodies 22, 32 are less likely to be worn.

In the first embodiment described above, as shown in FIG.
Applying the second extension change point H to 222 and 322, the outer peripheral end portions 22b and 3
Although the wall thickness is made thin up to the 2b side, it may be made thin by applying the extension change point to the outer wall. For example, as shown in FIG. 6, if the wall thickness is formed by the outer wall 223 of the fixed spiral body 22, the other conditions are made the same as those of the spiral bodies 22 and 32 of the first embodiment, and the base circle O is formed. Outer peripheral edge 22b side with the first expansion change point N as the boundary based on the first change point M (same as the first base point C) that has advanced 360 ° (angle COM) from the first base point C of the involute curve It is formed so that the wall thickness is thin by the thickness α.

Further, by using the fixed spiral body 22 whose outer wall 223 shown in FIG. 6 has a thin wall thickness and the movable spiral body 32 whose inner wall 322 shown in FIG. 1 has a thin wall thickness, both spiral bodies 22, The gap of 32 is 2α.

(Embodiment 2) The scroll compressor of this embodiment is an assembly of a scroll compressor having a fixed spiral body 22 and a movable spiral body 32, which have different extension and change points. Since other conditions are the same as those in the first embodiment, the description of the same configuration and operation will be omitted below.

The fixed spiral body 22 is the same as the fixed spiral body 22 of the first embodiment. That is, as shown in FIG. 1, the fixed scroll 22 has a second extension change point H applied to the inner wall 222.

In the movable scroll 32, as shown in FIG. 7, the inner wall 323 is
A wall thickness that is thinner by a thickness α from the second base point E on the base circle O toward the outer peripheral end 32b side with the extension change point Q based on the change point P that has advanced 270 ° (angle EOP) in the direction of extension of the involute curve. It is formed so that.

In this scroll type compressor, if the state of the fixed scroll 22 and the movable scroll 32 shown in FIG.
Both spiral bodies 22, 32 form a pair of compression chambers 5a, 5b, and communicate the compression chamber 51 immediately before discharge with the discharge port 61.
In this state, the compression chambers 5a and 5b have a gap of thickness α, but the compression chamber 51 is sealed by two points I and J. In the state shown in FIG. 9 where the crank angle is π / 2,
The compression chambers 5a and 5b also have a gap of thickness α, and
Is sealed by two points I and J, and a new pair of compression chambers
5c and 5d are being formed. Thereafter, in the state shown in FIG. 10 where the crank angle is π, the first and second extension points D and F of both spiral bodies 22 and 32 coincide with the contact points I and J, and the second extension change point H. Coincides with contact point K. That is, the compression chamber 5a has two points K,
It is sealed by J and the compression chamber 5b has a gap of thickness α,
The compression chamber 51 is closed by two points I and J. 8th-10th
When the compression chamber 51 shown in the drawing pushes the discharge valve 62 (see FIG. 13) open, the compressed fluid is discharged from the discharge port 61. In the state shown in FIG. 11 where the crank angle is 3π / 2, the extension change point Q coincides with the contact point L. That is, the compression chamber 5
The a and 5b are slidably contacted at the two points K and L on the side of the central end portions 22a and 32a from the second extension change point H and the extension change point Q, and soon become a single compression chamber 51, and the compression chambers 5c and 5d. Are formed and the state shown in FIG. 8 is reached. After that, the states shown in FIGS. 8 to 11 are repeated to complete the compression cycle of the pair of compression chambers at the crank angle of 4π.

Therefore, in this scroll type compressor,
As shown in the figure, when the compression chamber 51 is in the discharge stage,
The two spiral bodies 22, 32 are in sliding contact with the second extension change point H and two points I, J on the side of the central ends 22a, 32a from the extension change point Q, and the compression chamber 51
Is in a sealed state. In addition, the compression chamber 5a shown in FIG.
Is in a sealed state because the movable scroll 32 is in sliding contact with the fixed scroll 22 at the second extension change point H. Therefore, even if there is a processing error or the like in both spiral bodies 22, 32,
The compression chamber 51 immediately before discharge can be suitably sealed, and one of the compression chambers 5a and 5b, which is in the discharge stage in the next cycle, can also be suitably sealed.

Further, in this scroll type compressor, both spiral bodies 22 and 32 are supported at two points I and J until just before the crank angle π. Then, from the moment of crank angle π shown in FIG.
Immediately after the crank angle 3π / 2 shown in the figure, that is, from the moment when the two spiral bodies 22, 32 are slidably contacted with each other at a connecting line including an inscribed arc having a smaller radius of curvature, the pair of compression chambers 5a, 5b is a single compression chamber.
Until it is set to 51, the two spiral bodies 22, 32 have central ends with the first and second inflection points D, F (see FIGS. 1 and 7) as boundaries.
Even if the sliding contact is made on the side of 22a, 32a, both spiral bodies 22, 32 have three points I,
Supported by J and K. Therefore, since the force is dispersed as compared with the two-point support, the two spiral bodies 22, 32 come into contact with each other with a small surface pressure, and the central end portions 22a, 32a of the both spiral bodies 22, 32 are less likely to be worn.

In the second embodiment, as shown in FIG.
Although the extension change point Q is applied to 323 and the wall thickness is thinned to the outer peripheral end 32b side, the extension change point may be applied to the outer wall. For example, as shown in FIG. 12, if the wall thickness of the outer wall 324 of the movable spiral body 32 is made thin, other conditions are made the same as those of the spiral bodies 22 and 32 of the first embodiment, and the base circle O is placed. First of
The wall thickness is reduced by the thickness α to the outer peripheral end 22b side with the extension change point V based on the change point U (same as the origin A) that has advanced 270 ° (angle COU) from the base point C in the direction of extension of the involute curve. To be formed.

[Effects of the Invention] As described in detail above, in the scroll compressor of the present invention in which the central ends of both spiral bodies are improved in strength, at least one of the inner and outer walls of at least one of the spiral bodies is the second one. Alternatively, since the outer peripheral end portion is formed to have a thin wall thickness with the second expansion change point as a boundary, the compression chamber immediately before discharge can be suitably sealed, and wear of both spirals can be reduced. .

[Brief description of drawings]

1 to 6 relate to Example 1 of the present invention, FIG. 1 is an enlarged schematic view of a fixed scroll and a movable scroll, and FIGS. 2 to 5 are cross-sectional views showing a meshed state of both scrolls, and FIG. The figure is an enlarged schematic view of another fixed spiral body. 7 to 12 relate to Embodiment 2 of the present invention, FIG. 7 is an enlarged schematic view of a movable spiral body, FIGS. 8 to 12 are sectional views showing a meshed state of both spiral bodies, and FIG. It is an expansion schematic diagram of a movable spiral body. FIG. 13 is a vertical sectional view of the scroll compressor. FIG. 14 and FIG. 15 are cross-sectional views showing a meshed state of both conventional spiral bodies. 1 ... Housing, 2 ... Fixed scroll 21 ... Fixed side plate, 22 ... Fixed scroll 22a ... Center end, 22b ... Outer end 221, 223 ... Outer wall 222 ... Inner wall, 3 ... Movable Scroll 31 …… Movable side plate, 32 …… Movable scroll 32a …… Center end, 32b …… Outer peripheral end 321,324 …… Outer wall 322,323 …… Inner wall C …… First base point, D …… First Extension point E ... 2nd base point, F ... 2nd extension point G ... 2nd change point, M ... 1st change point, P, U ... change point H ... 2nd extension point , N …… Changes in the first extension, Q, V
…… Changes in development O …… Basic circle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Izumi 2-chome Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation (56) Reference JP-A-58-13184 (JP, A) JP-A-SHO 60-222580 (JP, A) JP-A 1-211601 (JP, A)

Claims (1)

(57) [Claims] 1. A fixed scroll comprising a fixed side plate fixed in a housing, and a fixed scroll body integrally formed on one surface of the fixed side plate and having inner and outer walls formed based on an involute curve, and the housing. A movable side plate rotatably supported in the inside of the movable side plate, and an inner and outer wall formed integrally with one surface of the movable side plate based on an involute curve, and meshed with the fixed spiral body at 180 ° out of phase with each other. And a movable scroll composed of a movable scroll body, wherein the fixed scroll body and the movable scroll body have an involute curve of the outer wall starting from a first extension point based on a first base point on a base circle, and the inner wall Starting from a second extension point based on a second base point on the base circle, the inner and outer walls connect the first extension point and the second extension point with a connecting line including at least two inscribed arcs. Formed by A scroll-type compressor in which a compression chamber formed between the fixed scroll and the fixed scroll is formed so as to move toward the center while sequentially reducing the volume thereof by the orbital motion of a dynamic scroll, wherein the fixed scroll and the movable scroll are At least one of the first wall is the first wall near the first base point on the base circle, which has advanced 360 ° in the direction in which the involute curve extends.
The first expansion based on the change point is formed so as to have a thin wall thickness up to the outer peripheral edge with the change point as a boundary, and / or the inner wall is extended from the second base point on the base circle in a direction in which the involute curve extends. A scroll compressor characterized in that it is formed to have a thin wall thickness up to the outer peripheral end with a second extension change point as a boundary based on the second change point in the vicinity of the progress.