JP2005273453A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the strength of a lap tip part of a scroll compressor and to reduce power loss caused by excessive compression. <P>SOLUTION: A fixed scroll 10 and a movable scroll 20 with spiral laps 13, 23 erected on the inner surfaces of end plates 11, 21 respectively are joined to form compression chambers P1, P2 variable in volume between both laps. A scroll start point A of each outer peripheral surface 13a separates from an inner peripheral surface when going over a scroll start point C which is near a seal off position of each inner peripheral surface 13b, and both compression chambers communicate with a center chamber P3. Each lap is formed large in the thickness of a center side tip part, and the inner surface abutting on the center chamber of at least one end plate is formed with counter boring parts 15, 25 communicating the center chamber with at least one of both compression chambers P1, P2 when the scroll start point on the outer peripheral surface goes over a part near the scroll start point on the inner peripheral surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scroll compressor, and more particularly to a scroll compressor that reduces power loss due to overcompression.

As such a scroll compressor that reduces power loss due to overcompression, there is a technique disclosed in Japanese Patent Laid-Open No. 2000-120565 (Patent Document 1). This is a fixed scroll in which a spiral wrap made of an involute curve is erected on an end plate having a discharge hole in the center, and a turning scroll in which a spiral wrap made of an involute curve is erected on the end plate facing this fixed scroll , And a scroll compressor comprising a plurality of compression chambers. The winding start portion of each scroll wrap is externally connected to the winding start point of the outer involute curve. It is formed by an arc and an inner arc that is discontinuously connected to the winding start point of the inner involute, and the center point of the outer arc is provided on the tangent line of the base circle passing through the winding start point of the outer involute curve, while the outer arc and The inner arc contact is provided on a straight line connecting the center point of the outer arc and the center point of the inner arc. According to such a configuration, it is possible to obtain an effect that the gas passage immediately after discharge is widened, an increase in compressor input due to discharge resistance is reduced, and compressor efficiency can be improved.
Japanese Unexamined Patent Publication No. 2000-120565 (paragraph [0006], paragraph [0015]], FIGS. 2 to 4).

  In the prior art scroll shown in FIG. 7 of Patent Document 1, the inner involute of the wrap is connected to extend to the outer arc at the tip without providing the inner arc, and the outer involute of one wrap and the other Each of the contact positions with the inner involute moves to the tip side with the turning of the movable scroll, and the volume of each compression chamber decreases. Immediately before the compression ratio of each compression chamber reaches a value at which a predetermined output pressure is obtained during rated operation, the contact position of the outer involute of one lap reaches the winding start point and the contact of the inner involute of the other wrap When the position reaches the seal-off position and the winding start point of the outer involute of one lap moves beyond the seal-off position to the center side, the winding starting point moves away from the inner involute and the center of both wraps. The dimensional relationship of each part is set so that both compression chambers are communicated with a central chamber formed in the above and provided with a discharge hole. The speed at which this winding start point moves away with respect to the turning angle of the orbiting scroll wrap is small, and therefore the communication area of the gas passage between each compression chamber and the central chamber immediately after the start of discharge is not sufficient, so that the gas in the compression chamber is overcompressed. Causes power loss. If the orbiting scroll further rotates by a considerable angle after the winding start point of the outer involute of one lap exceeds the seal-off position, a part of the discharge hole is opened in one compression chamber and the compression chamber directly discharges. It comes to communicate with the hole. This communication is performed only for one of the compression chambers, and as indicated by the broken line d in FIG. 10, the opening start angle is delayed and the rate of increase in the communication area is small.

  On the other hand, in Patent Document 1, an inner arc that is discontinuously connected to the winding start point of the inner involute of the wrap is provided, and this inner arc is located outside the extended portion of the inner involute further from the winding start point toward the base circle. Therefore, when the orbiting scroll turns and the winding start point of the outer involute curve exceeds the winding start point near the seal off position of the inner involute, the winding start point of the outer involute curve and the inner arc of the inner involute The gap between the two is larger than that of the prior art in which no inner arc is provided, and the above-described effects can be obtained. However, in the above-described technique of Patent Document 1, in order to sufficiently secure a gas passage area after the start of discharge and sufficiently prevent overcompression, the thickness of the front end portion on the center side of the wrap is set to the start of winding of the inner involute. Since it is necessary to make it considerably smaller than the thickness of the lap before this point, when considering durability, the strength of the center side tip is insufficient and sliding with the other side scroll or The risk of damage due to the force of compressed gas or the like increases.

  The present invention increases the strength of the tip of the wrap by increasing the thickness of at least a part of the tip of the wrap as compared with the prior art, and provides a counterbore on the inner surface that is the center of the end plate of the scroll. An object of the present invention is to prevent damage to the tip of the wrap and reduce power loss due to overcompression.

  To this end, the scroll compressor according to the present invention includes a fixed scroll in which a spiral fixed side wrap is erected on the inner surface of the fixed side end plate, and a movable scroll in which a spiral movable side wrap is erected on the inner surface of the movable side end plate. Are joined so that one outer peripheral surface of both laps contacts the other inner peripheral surface, and the volume gradually decreases with the turning of the movable scroll with respect to the fixed scroll between the two wraps, and at least moves to the center side. A pair of compression chambers are formed, and when the swirl advances and the winding start point of the spiral on each outer peripheral surface exceeds the vicinity of the seal-off position on each inner peripheral surface, the winding start point is separated from the inner peripheral surface and the two compression chambers are separated. In a scroll compressor that communicates with a central chamber formed at the center of both wraps and that communicates discharge holes with the central chamber, each inner peripheral surface of each wrap is wound around an inner peripheral surface that is a seal-off position. Starting point Each lap is a concave arc surface that enters inside the original spiral line of the inner peripheral surface within a range that does not interfere with the winding start point of the outer peripheral surface of the wrap that abuts at least a part of the front end on the center side. The thickness of at least a part of the tip portion that is the center side of the scroll is larger than the thickness of the wrap that is on the near side from the vicinity of the seal-off position, and the inner surface that is in contact with the central chamber of at least one end plate of both scrolls When the turning progresses and the winding start point of the outer peripheral surface exceeds the vicinity of the winding start point of the inner peripheral surface, a counterbore portion is formed which communicates the central chamber with at least one of both compression chambers. .

  In the scroll compressor described in the preceding paragraph, the counterbore formed on at least one of the end plates is circular when viewed from the direction of the orbiting axis of the movable scroll, and is formed on the inner peripheral surface of the wrap erected on the end plate from the vicinity of the discharge hole. It is preferable to form it eccentrically toward the seal-off position direction.

  In the scroll compressor described in the preceding paragraph, the counterbore formed on at least one of the end plates is an oval shape when viewed from the orbiting axis direction of the movable scroll, and the inner portion of the wrap standing on the end plate from the vicinity of the discharge hole. It is preferable to form it so as to extend in the direction of the seal-off position on the peripheral surface.

  2. The scroll compressor according to claim 1, wherein the counterbore portion formed on at least one of the end plates is erected on the end plate in a fan shape with the vicinity of the discharge hole as seen from the swivel axis direction of the movable scroll. It is preferable to form it so that it may extend toward the seal-off position direction of the inner peripheral surface of the wrap.

  According to the first aspect of the present invention, each inner peripheral surface of each wrap has at least a part of the tip portion that is closer to the center side than the winding start point of the inner peripheral surface that is the seal-off position. As long as it does not interfere with the winding start point of the outer peripheral surface, the thickness of at least a part of the tip portion on the center side of each lap as a concave arc surface entering the inner spiral surface of the inner peripheral surface is near the seal-off position. The thickness of the wrap is larger than the thickness of the wrap on the near side, so even if durability is taken into consideration, the tip of the wrap will not have insufficient strength. There is no possibility of causing damage due to the force of. In this way, in the state where the winding start point of the outer peripheral surface of one wrap exceeds the seal-off position of the inner peripheral surface of the other wrap, the winding start point of the outer peripheral surface is compared with the technique of Patent Document 1. In addition to the above, in the invention of claim 1, in addition to the above, on the inner surface in contact with the central chamber of at least one end plate of both scrolls, the turning progresses and the winding start point of the outer peripheral surface Since the counterbore that connects the central chamber to at least one of the two compression chambers is formed when the vicinity of the winding start point of the inner peripheral surface is exceeded, the winding start point of the outer peripheral surface of one wrap is the winding of the inner peripheral surface. In the state beyond the vicinity of the starting point, at least one of the two compression chambers is communicated with the central chamber to which the discharge hole is communicated by this counterbore, so that the communication area between the compression chamber and the central chamber is sufficiently large. can do. Thereby, there is no possibility of causing damage due to insufficient strength at the tip of the lap, and power loss of the scroll compressor due to overcompression can be reduced.

  The counterbore formed on at least one end plate is circular as seen from the orbiting axis direction of the movable scroll, and is decentered from the vicinity of the discharge hole toward the seal-off position on the inner peripheral surface of the wrap standing on the end plate. According to the invention of claim 2 formed as described above, since the counterbore part can be easily processed, the manufacturing cost can be reduced.

  The counterbore formed on at least one of the end plates is oval when viewed from the orbiting axis direction of the movable scroll and extends from the vicinity of the discharge hole toward the seal-off position on the inner peripheral surface of the wrap standing on the end plate. According to the invention of claim 3 formed as described above, the area of the oval counterbore portion is smaller than that of the circular counterbore portion, so that the influence on the member attached to the inner surface near the center of the end plate of the scroll is reduced. be able to.

  The counterbore formed on at least one of the end plates is in the shape of a fan having a caulking portion in the vicinity of the discharge hole as seen from the orbiting axis direction of the movable scroll in the direction of the seal-off position of the inner peripheral surface of the wrap erected on the end plate According to the invention of claim 4 formed so as to extend in the direction where the winding start point of the outer peripheral surface of the other scroll wrap is located in the vicinity of the winding start point of the inner peripheral surface of one scroll wrap. The large arc-shaped outer peripheral portion on the seal-off side of the fan-shaped counterbore portion formed in one scroll is generally along the outer peripheral surface of the tip end portion of the other scroll wrap. If the movable scroll turns beyond the position, the communication area between the compression chamber and the central chamber via the counterbore portion increases rapidly. Therefore, even when the thickness of the tip of the wrap is increased in order to increase the strength of the tip of the wrap, the power loss of the scroll compressor due to overcompression can be reduced.

  First, a first embodiment of a scroll compressor according to the present invention will be described with reference to FIGS. As shown mainly in FIGS. 1 and 2, the scroll compressor of this embodiment includes a fixed side end plate 11 and a fixed scroll 10 in which a spiral fixed side wrap 13 is erected on its inner surface, a movable side end plate 21 and its The movable scroll 20 includes a movable scroll 20 having a spiral movable side wrap 23 standing on the inner surface. The movable scroll 20 has a side on which the outer peripheral portion of the inner surface of the movable side end plate 21 is erected and fixed on the outer peripheral portion of the fixed end end plate 11. The upper end surface of the peripheral wall 12 is slidably contacted (see the modification shown in FIG. 5), and is assembled so as to turn without rotating relative to the fixed scroll 10. In the scrolls 10 and 20, the outer peripheral surface 13a of the fixed side wrap 13 and the inner peripheral surface 23b of the movable side wrap 23 are brought into contact with each other at a plurality of locations to form a plurality of first compression chambers P1 therebetween. The outer peripheral surface 23a of the movable side wrap 23 and the inner peripheral surface 13b of the fixed side wrap 13 are in contact with each other at a plurality of locations and joined so as to form a plurality of second compression chambers P2 therebetween. Both the compression chambers P1, P2 move to the center side while the volume gradually decreases as the movable scroll 20 turns with respect to the fixed scroll 10, and compress the gas confined in the inside thereof.

  A central chamber P3 is formed at the center of both wraps 13, 23 between the two end plates 11, 21, and circular counterbore portions 15, 25 are formed on the inner surfaces of the end plates 11, 21 in contact with the central chamber P3. Is formed. The fixed scroll 10 is formed with a circular discharge hole 16 communicating with the central chamber P3 through the counterbore 15 so as to penetrate in the direction of the turning axis of the movable scroll 20. A reed valve 17 is provided which allows outflow but prevents inflow.

  Next, the shape of each lap 13, 23 will be described with reference to FIG. In the following, the shape of the fixed wrap 13 will be described, but in the case of a symmetrical scroll, the shapes of both wraps 13 and 23 are the same. The outer peripheral surface 13a and the inner peripheral surface 13b of the fixed side wrap 13 are made of a part of an involute curve having a common base circle G. The involute curve of the outer peripheral surface 13a of the fixed side wrap 13 starts from the winding start point A, and the two-dot chain line H1 indicates an extended portion reaching the basic circle G of the omitted involute curve. The most distal end of the fixed side wrap 13 is a convex arc surface (convex arc surface) 13c having a radius R2 centered on a point O2 on the tangent to the basic circle G passing through the winding start point A. The inner peripheral surface 13b of the fixed wrap 13 is composed of an involute curve portion and a concave arc surface 13d. The involute curve portion starts from the winding start point C, and the two-dot chain line H2 extends to the base circle G of the omitted involute curve. Shows the part. The portion of the inner peripheral surface 13b that is closer to the center than the winding start point C is a concave arc surface (concave arc surface) 13d having a radius R1 with the point O1 as the center, and the tip portion thereof is a concave arc surface 13d and a convex arc. The straight portion 13e that is in contact with the surface 13c is connected to the convex arc surface 13c. The concave arc surface 13d of this embodiment has a shape in which it extends from the winding start point C to the outside of the extension part H2 of the involute curve of the inner peripheral surface 13b and then crosses the extension part H2 at the point D and enters the inside thereof. is there. The thickness of the tip end portion of the fixed side wrap 13 in which the concave arcuate surface 13d has entered the inside of the extension portion H2 is the front side (the side opposite to the center side) from the winding start point C as indicated by reference numeral I. It becomes larger than the thickness of the wrap 13. The winding start point C of the inner peripheral surfaces 13b and 23b of the laps 13 and 23 in the first embodiment is set to be near the seal-off position described above.

  The counterbore portion 15 of the fixed side end plate 11 is provided on the inner surface in contact with the central chamber P3, is circular when viewed from the direction of the orbiting axis of the movable scroll 20, surrounds the discharge hole 16, and the fixed side end plate 13 of the fixed side end plate 11 is fixed. The inner circumferential surface 13b is formed eccentrically toward the seal-off position direction, and the depth is constant. The spot facing portion 25 formed on the movable side end plate 21 has the same positional relationship as the spot facing portion 15 with respect to the movable side wrap 23 except that the discharge hole 16 is not provided. As shown in FIG. 1, the counterbore portions 15 and 25 are configured such that the winding start point A of the outer peripheral surfaces 13 a and 23 a of the wraps 13 and 23 is the winding start point C of the inner peripheral surfaces 23 b and 13 b of the wraps 23 and 13. In the state of being located in the vicinity, the compression chambers P1 and P2 are not communicated with each other. However, as shown in FIGS. 2 and 3, the winding start point A of each of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 is the wrap 23. , 13 beyond the vicinity of the winding start point C of the inner peripheral surfaces 23b, 13b, and into the range of the inner arc portions 23d, 13d, they are communicated with the compression chambers P1, P2, and the counterbore portions 15, 25 are connected to each other. The compression chambers P1, P2 are communicated with the central chamber P3. The communication from the first and second compression chambers P1, P2 to the discharge hole 16 is between the winding start point A of the outer peripheral surfaces 13a, 23a of the wraps 13, 23 and the inner arc portions 23d, 13d of the inner peripheral surfaces 23b, 13b. There are those that are made via the gap d and those that are made via the counterbore portions 15 and 25 described above. The latter communication from the compression chambers P1 and P2 to the discharge hole 16 is shown in FIG. As shown by the characteristic of the solid line a of 10, it starts at a faster rotation angle than the characteristic of the broken line d in the technique of Patent Document 1 described above, and the rate of increase in the communication area is large, and the first compression chamber P1. Since both the second compression chamber P2 and the counterbore portions 15 and 25 are communicated with each other, the communication area between the compression chambers P1 and P2 and the discharge hole 16 is smaller than that in the case of the technique of Patent Document 1. It will be quite large.

  In the first embodiment configured as described above, the compression chambers P1 and P2 for compressing the gas confined in the compression chambers P1 and P2 whose volume gradually decreases as the movable scroll 20 turns with respect to the fixed scroll 10 are compressed into the wrap 13. 1 until the winding start point A of each of the outer peripheral surfaces 13a, 23a reaches the vicinity of the winding start point C of each of the inner peripheral surfaces 23b, 13b of the laps 23, 13 until a predetermined output pressure is reached. As shown in FIGS. 2 and 3, after the winding start point A reaches the vicinity of the winding start point C and reaches a predetermined output pressure, first, the outer peripheral surfaces 13a and 23a are not communicated with the central chamber P3. The winding start point A is separated from the inner arc portions 23d and 13d of the inner peripheral surfaces 23b and 13b, and the compression chambers P1 and P2 are communicated with the central chamber P3. Next, the counterbore portions 15 and 25 are communicated with the compression chambers P1 and P2. Being pressure The area of communication between the chambers P1, P2 and the central chamber P3 is increased.

  According to such a 1st embodiment, since the thickness of the tip part of each lap 13 and 23 becomes larger than the thickness of each lap 13 and 23 which becomes the near side rather than winding start point C, it is durable. In consideration of the above, the strength of the tip ends of the wraps 13 and 23 does not become insufficient, and there is no possibility of causing damage due to sliding with the other side scroll, the scrolls 10 and 20 or force due to compressed gas. In this way, the winding start point A of the outer peripheral surface 13a (23a) of one wrap 13 (23) exceeds the seal-off position of the inner peripheral surface 23b (13b) of the other wrap 23 (13). In the state, the gap d between the winding start point A of the outer peripheral surface 13a (23a) and the inner arc portion 23d (13d) of the inner peripheral surface 23b (13b) is reduced as compared with the technique of Patent Document 1. However, in the first embodiment, the counterbore portions 15 and 25 are communicated with the compression chambers P1 and P2 as described above, and the communication area between the compression chambers P1 and P2 and the central chamber P3 is increased. Therefore, there is no possibility of causing damage due to insufficient strength at the front ends of the wraps 13 and 23 of the scrolls 10 and 20, and power loss of the scroll compressor due to overcompression can be reduced.

  In the modification shown in FIGS. 5 and 6, the inner surface of the end plate 11 (21) of one scroll 10 (20) abutted against each other and the top surface of the wrap 23 (13) of the other scroll 21 (20) In order to prevent wear between them, spiral wear prevention plates 18 and 28 made of thin plates (for example, iron plates having a thickness of 0.3 mm) are provided on the inner surfaces of the end plates 11 and 21 except for the wraps 13 and 23. It is in close contact.

  In this modification, a step corresponding to the thickness e of the wear preventing plates 18 and 28 is formed between the wear preventing plates 18 and 28 and the inner surfaces of the end plates 11 and 21 as shown in FIG. Further, as shown in the front sectional view of FIG. 6, it is necessary to prevent the wear preventing plates 18 and 28 from being applied to the counterbore portion 15, and the front end portion 18a on the center side can be sharpened to prevent turning. However, it is necessary to form an arc having a considerably large radius. Accordingly, in the illustrated state where the winding start point A of the outer peripheral surface 23a of the movable side wrap 23 reaches the winding start point C of the outer peripheral surface 13a of the fixed side wrap 13, the root portion of the arcuate tip portion 18a of the wear preventing plate 18 is illustrated. In the range indicated by the symbol α1 extending from the vicinity to the vicinity of the winding start point C, it corresponds to the thickness of the wear preventing plate 18 between the inner surface of the fixed side end plate 11 of the fixed scroll 10 and the top surface of the movable side wrap 23 of the movable scroll 20. A gap e is generated, and the second compression chamber P2 and the central chamber P3 communicate with each other through the gap e. This gap e is obtained before the winding start point A of the outer peripheral surface 23a of the movable wrap 23 reaches the winding start point C of the outer peripheral surface 13a of the fixed wrap 13 and the second compression chamber P2 reaches a predetermined output pressure. Since the second compression chamber P2 and the central chamber P3 communicate with each other, the gas in the central chamber P3 having a predetermined output pressure leaks into the second compression chamber P2. Similarly, the gas in the central chamber P3 leaks into the first compression chamber P1. Since the leaked gas is recompressed by the compression chambers P1 and P2, there is a problem that the efficiency of the scroll compressor is lowered.

  This problem is reduced by the second embodiment shown in FIG. In this second embodiment, the counterbore 15A provided on the inner surface of the fixed side end plate 11 in contact with the central chamber P3 is oval when viewed from the orbiting axis direction of the movable scroll 20, and both sides thereof are on the outer periphery of the discharge hole 16. It contacts and extends in parallel toward the seal-off position direction of the inner peripheral surface 13b of the fixed-side wrap 13 of the fixed-side end plate 11, and the arc at the tip is located at the seal-off position or on the inner side of the collar. The spot facing portion 25A formed on the movable side end plate 21 has the same positional relationship as the spot facing portion 15A with respect to the movable side wrap 23 except that the discharge hole 16 is not provided. The structure of the second embodiment excluding the spot facings 15A and 25A is the same as that of the first embodiment. As shown in FIG. 7, the counterbore portions 15A and 25A have a winding start point A on each of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 and a vicinity of the winding start point C of each of the inner peripheral surfaces 23b and 13b of the wraps 23 and 13. In the state of being located, the compression chambers P1 and P2 are not communicated with each other. However, as in the first embodiment, the winding start points A of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 are the respective wraps 23 and 13. If it passes the vicinity of the winding start point C of the inner peripheral surfaces 23b and 13b and enters the range of the inner arc portions 23d and 13d, they are communicated with the compression chambers P1 and P2, and are compressed through the counterbore portions 15A and 25A. The chambers P1 and P2 communicate with the central chamber P3. The communication area from both the compression chambers P1 and P2 to the discharge hole 16 through the counterbore portions 15A and 25A of the second embodiment is indicated by a solid line a as shown by a one-dot chain line b in FIG. Although it becomes smaller than the case of 1st Embodiment, it becomes larger than the case of the technique of the patent document 1 shown with the broken line d.

  FIG. 8 shows a front cross-sectional view of a modification in which a wear preventing plate 18A (wear preventing plate 28A is not shown) is provided in the second embodiment. Also in this modified example, the thickness of the wear preventing plate 18 is equivalent to the thickness between the inner surface of the fixed side end plate 11 of the fixed scroll 10 and the top surface of the movable side wrap 23 of the movable scroll 20 as in the case of the first embodiment. A gap e is formed, and the second compression chamber P2 and the central chamber P3 are communicated with each other by the gap e. However, since the counterbore 15A of the second embodiment is narrower than the counterbore 15 of the first embodiment, the tip 18Aa of the wear preventing plate 18A is fixed side wrap more than in the case of the first embodiment. 13 approaches the winding start point C of the inner peripheral surface 13b. Accordingly, in the illustrated state where the winding start point A of the outer peripheral surface 23a of the movable side wrap 23 reaches the winding start point C of the outer peripheral surface 13a of the fixed side wrap 13, the root portion of the arcuate tip portion 18a of the wear preventing plate 18 is illustrated. Since the range indicated by the symbol α2 from the vicinity to the vicinity of the winding start point C is narrower than the range indicated by the symbol α1 in the first embodiment, the amount of gas leaking from the central chamber P3 to the first and second compression chambers P1 and P2. Is less than in the first embodiment. Therefore, according to 2nd Embodiment, the problem that the efficiency of a scroll compressor falls by such a gas leak is reduced.

  Next, the third embodiment shown in FIG. 9 will be described. In this third embodiment, the spot facing portion 15B provided on the inner surface of the fixed side end plate 11 in contact with the central chamber P3 has a fan shape with the vicinity of the discharge hole 16 as a caulking portion when viewed from the turning axis direction of the movable scroll 20, and is fixed. It forms so that it may extend toward the seal-off position direction of the internal peripheral surface 13b of the stationary-side wrap 13 erected on the side end plate 11. The spot facing portion 25B formed on the movable side end plate 21 has the same positional relationship as the spot facing portion 15B with respect to the movable side wrap 23 except that the discharge hole 16 is not provided. The structure of the third embodiment excluding the spot facings 15B and 25B is the same as that of the first and second embodiments. As shown in FIG. 9, the counterbore portions 15B and 25B have a winding start point A on each of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 in the vicinity of the winding start point C of each of the inner peripheral surfaces 23b and 13b of the wraps 23 and 13. Is not communicated with each of the compression chambers P1 and P2, but has a large arcuate shape on the seal-off side of the fan-shaped counterbore 15B (25B) formed on one scroll 10 (20). The outer peripheral portion is substantially along the outer peripheral surface 23a (13a) of the tip portion of the wrap 23 (13) of the other scroll 20 (10). Therefore, if the movable scroll 20 turns beyond this position, the length of the opening between the two compression chambers P1, P2 and the central chamber P3 increases abruptly. Therefore, the double compression through the counterbore portions 15B, 25B. The communication area between the chambers P1, P2 and the central chamber P3 increases abruptly as indicated by a two-dot chain line c in FIG.

  As described above, the communication from the first and second compression chambers P1 and P2 to the discharge hole 16 includes the winding start point A of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 and the inner arc portions of the inner peripheral surfaces 23b and 13b. There are ones that are made via the gap d between 23d and 13d and ones that are made via the counterbore portions 15 and 25 described above. In each of the above-described embodiments, the inner circumference of the wraps 13 and 23 The concave arcuate surfaces 13d and 23d of the surfaces 13b and 232 exit from the winding start point C to the outside of the involute curve extension H2 of the inner peripheral surface 13b, intersect the extension H2 at the point D and enter the inside thereof. In order to increase the communication area between the compression chambers P1, P2 and the central chamber P3 immediately after the seal-off position, the concave arc surfaces 13d, 23d are involute curves of the inner peripheral surfaces 13b, 23b. Extension H2 The outer peripheral surface 13a due to the exit to the outside, the winding start point A and the inner circumferential surface 23b of the 23a, the inner arc portion 23d of the 13b, the increase in the gap d between the 13d have contributed to some extent. However, according to the third embodiment, the communication area between the compression chambers P1, P2 and the central chamber P3 via the counterbore portions 15B, 25B increases rapidly. The involute is within a range in which the front end portion that is closer to the center than the winding start point C of the involute curve that is the peripheral surfaces 13b and 23b does not interfere with the winding start point A of the outer peripheral surfaces 13a and 23a of the wraps 13 and 23 that are in contact therewith. The concave arc surfaces 13d and 23d that enter the inside of the extended portion of the curve can sufficiently secure the communication area between the compression chambers P1 and P2 and the central chamber P3, and can sufficiently reduce power loss due to overcompression. . In this way, the strength can be ensured by sufficiently increasing the thickness of the tip of each wrap 13, 23.

  In each of the above-described embodiments, the pair of wraps 13 and 23 and the pair of counterbore portions 15 and 25 (15A, 25A; 15B, 25B) are arranged in a point symmetry with the same shape. However, the present invention is not necessarily required to do this, and the position of the winding start point A of the outer peripheral surfaces 13a, 23a of the pair of wraps 13, 23 or the winding start point C of the inner peripheral surfaces 13b, 23b is shifted. The shape of the counterbore parts 15, 25 (15A, 25A; 15B, 25B) may be slightly changed, and the arrangement of each pair may be slightly shifted from the point-symmetrical position. By doing so, the suction d into each compression chamber P1, P2, the gap d between the winding start point A of the outer peripheral surfaces 13a, 23a of the wraps 13, 23 and the inner arc portions 23d, 13d of the inner peripheral surfaces 23b, 13b or By shifting the communication timing between the compression chambers P1, P2 and the discharge holes 16 through the counterbore portions 15, 25 (15A, 25A; 15B, 25B), the pressure peaks of the compression chambers P1, P2 By shifting the position, the effect of reducing overcompression can be further enhanced.

  In each of the above-described embodiments, the counterbore portions 15 and 25 (15A and 25A; 15B and 25B) are provided on the fixed side end plate 11 and the movable end end plate 21, respectively. When there are few, you may implement by providing a counterbore part in either one of both the end plates 11 and 21.

It is front sectional drawing of the center part of 1st Embodiment of the scroll compressor by this invention. It is 2-2 sectional drawing of FIG. It is front sectional drawing similar to FIG. 1 in the state in which the movable scroll turned. It is a front view which shows the shape of the center part of a scroll. It is a cross-sectional view showing a modification of the first embodiment. It is front sectional drawing of the center part and its periphery of the modification shown in FIG. It is front sectional drawing of the center part of 2nd Embodiment of the scroll compressor by this invention. It is front sectional drawing of the center part of the modification of 2nd Embodiment, and its periphery. It is front sectional drawing of the center part of 3rd Embodiment of the scroll compressor by this invention. It is a figure which shows the change characteristic of the communication area between a compression chamber and a center chamber with respect to the rotation angle of a movable scroll.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fixed scroll, 11 ... Fixed side end plate, 13 ... Fixed side wrap, 13a, 23a ... Outer peripheral surface, 13b, 23b ... Inner peripheral surface, 13d, 23d ... Concave arc surface (concave arc surface), 15, 25, 15A , 25A, 15B, 25B ... Counterbore part, 16 ... discharge hole, 20 ... movable scroll, 21 ... movable side end plate, 23 ... movable side wrap, P1, P2 ... compression chamber, P3 ... central chamber, A ... winding start point , C ... winding start point.

Claims (4)

A fixed scroll in which a spiral fixed side wrap is erected on the inner surface of the fixed side end plate, and a movable scroll in which a spiral movable side wrap is erected on the inner surface of the movable side end plate, and one outer peripheral surface of both wraps is the other Forming at least one pair of compression chambers that move toward the center while the volume gradually decreases with the turning of the movable scroll with respect to the fixed scroll between the two wraps so as to be in contact with the inner peripheral surface of the fixed scroll, When the swirl progresses and the winding start point of the spiral on each outer peripheral surface exceeds the vicinity of the seal-off position on each inner peripheral surface, the same winding start point is separated from the inner peripheral surface, and the both compression chambers are in contact with the two wraps. In the scroll compressor, which is communicated with a central chamber formed in the central portion and has a discharge hole communicated with the central chamber, each inner circumferential surface of each wrap is wound around the inner circumferential surface which is the seal-off position. start A concave arc that enters at least a part of the front end portion that is closer to the center than the original spiral line of the inner peripheral surface within a range that does not interfere with the winding start point of the outer peripheral surface of the wrap that is in contact therewith The thickness of at least a part of the tip portion on the center side of each wrap as a surface is larger than the thickness of the wrap on the near side from the vicinity of the seal-off position, and at least one of the end plates of both scrolls If the swirl advances and the winding start point of the outer peripheral surface exceeds the vicinity of the winding start point of the inner peripheral surface, the central chamber communicates with at least one of the two compression chambers on the inner surface of the central chamber. A scroll compressor characterized in that a counterbore part is formed. 2. The scroll compressor according to claim 1, wherein the counterbore portion formed on at least one of the end plates is circular as viewed from the direction of the orbiting axis of the movable scroll and is erected on the end plate from the vicinity of the discharge hole. A scroll compressor characterized in that it is formed to be eccentric toward the seal-off position direction of the inner peripheral surface of the wrap. 2. The scroll compressor according to claim 1, wherein the counterbore portion formed on at least one of the end plates is elliptical when viewed from the direction of the orbiting axis of the movable scroll and is erected on the end plate from the vicinity of the discharge hole. A scroll compressor characterized by being formed so as to extend toward the seal-off position of the inner peripheral surface of the wrap. 2. The scroll compressor according to claim 1, wherein the counterbore portion formed on at least one of the end plates has a fan shape with a vicinity of the discharge hole as seen from a turning axis direction of the movable scroll in the end plate. A scroll compressor characterized in that the scroll compressor is formed so as to extend toward the seal-off position direction of the inner peripheral surface of the wrap erected.

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