JP2007297943A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll compressor capable of improving efficiency of compression of the compressor while improving strength and workability of fixed side and movable side bottom plates. <P>SOLUTION: This scroll compressor is constituted in such a way that end walls 16a, 18a of at least either of fixed and movable scrolls 16, 18 are exposed into a compression chamber 71 and have exposed faces 16b, 18b positioned in a scope from abutting faces 68c, 70c abutted on the same end wall to slide-contact faces 68b, 70b being continuous with the abutting faces by predetermined plate thickness. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scroll compressor suitable for a refrigeration circuit used for air conditioning of a vehicle.

In this type of scroll compressor, a compression chamber is formed by the cooperation of a fixed spiral body integrally formed on the end wall of the fixed scroll and a movable spiral body integrally formed on the end wall of the movable scroll. After the refrigerant as the working fluid is sucked into the chamber and the sucked refrigerant is compressed, the compressed refrigerant is discharged from the discharge hole of the fixed scroll.
In order to ensure the airtightness of the compression chamber, the fixed and movable scrolls are provided with a spiral fixed side and a movable side bottom plate in which the other-side spiral body is in sliding contact with the tip seal (for example, Patent Document 1). reference).
Japanese Patent Laid-Open No. 10-9157

  In the scroll compressor disclosed in Patent Document 1, there is no fixed bottom plate around the discharge hole of the fixed scroll, and the end wall of the fixed scroll is exposed to the compression chamber to form an exposed surface. For this reason, in the periphery of the discharge hole, the exposed surface and the sliding contact surface of the movable spiral body on the fixed-side bottom plate have a step corresponding to the plate thickness of the fixed-side bottom plate. There is a problem that the volume of the space constituted by becomes a dead volume and the compression efficiency of the compressor decreases.

In view of this, it is conceivable to reduce the dead volume by forming the fixed end plate with a sharp tip at the center end so as to wind the center end of the fixed spiral body. However, since the tip has a sharp shape, it is difficult to process the fixed-side bottom plate, and the tip is easily cracked, so that the reliability of the fixed-side bottom plate is lowered.
On the other hand, the end wall of the movable scroll of Patent Document 1 is covered with the movable-side bottom plate so that the entire center end portion of the movable spiral body is wound, and there is almost no dead volume as described above. However, since the central end of the movable bottom plate is formed so as to wind the sharp tip of the central end of the movable spiral body, the central end of the movable bottom plate is the tip of the central end of the movable spiral body. And a concave shape with a large curvature radius. For this reason, the mold of the movable side bottom plate, that is, a so-called press mold structure must be sharp, and there is a problem that the strength of the press mold is lowered and the durability is lowered.

  The present invention has been made in view of such a problem, and an object thereof is scroll compression capable of improving the compression efficiency of the compressor while improving the strength and workability of the fixed side and movable side bottom plates. Is to provide a machine.

  In order to achieve the above object, a scroll compressor according to claim 1 is provided with an end wall having a discharge hole, a fixed scroll having a fixed spiral body integrally formed with the end wall, and an end wall facing the end wall. And a movable scroll having a movable spiral body that is integrally formed on the end wall and that discharges the working fluid from the compression chamber formed in cooperation with the fixed spiral body from the discharge hole, and is in sliding contact with the movable spiral body. A slidable contact surface, a spiral fixed bottom plate having a predetermined thickness from the slidable contact surface, and a contact surface that contacts the end wall of the fixed scroll, and a fixed spiral body A sliding contact surface, and a spiral movable bottom plate having a contact surface that contacts the end wall of the movable scroll with a predetermined thickness from the sliding contact surface. Any one of the end walls is exposed to the compression chamber, and It is characterized by having an exposed surface that is positioned within the range of sliding surface continuing to exist a predetermined thickness on the abutting surface from the contact surface to be in contact with the one end wall.

Further, the invention according to claim 2 is characterized in that the exposed surface is positioned flush with the sliding contact surface.
Furthermore, the invention according to claim 3 is characterized in that the fixed side and movable side bottom plates have the same shape.

  Therefore, according to the scroll compressor of the first aspect of the present invention, when the end wall of the fixed scroll has an exposed surface, the step between the exposed surface and the sliding surface of the movable spiral body in the fixed side bottom plate. And the dead volume resulting from this step is reduced. Therefore, in order to reduce the dead volume, the fixed-side bottom plate is not formed so as to involve the fixed spiral body. Thereby, the compression efficiency of the compressor is improved while ensuring the strength of the fixed-side bottom plate.

On the other hand, when the end wall of the movable scroll has an exposed surface, the movable spiral body and the movable side bottom plate have a clearance corresponding to the area of the exposed surface. Therefore, the movable side bottom plate is not formed so as to involve the movable spiral body. As a result, the press die is prevented from having a sharp shape, and the life of the press die of the movable side bottom plate is improved.
According to the second aspect of the present invention, the level difference between the exposed surface of the end wall of the fixed scroll and the sliding contact surface of the fixed side bottom plate, and the sliding contact between the exposed surface of the end wall of the movable scroll and the movable side bottom plate. Since the step with the surface is eliminated and the dead volume resulting from these steps becomes zero, the compression efficiency of the compressor is greatly improved.

  Furthermore, according to the invention described in claim 3, since the fixed side and movable side bottom plates can be made common, the cost can be reduced and the productivity can be improved by making the parts common.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a scroll compressor, which is incorporated in a refrigeration circuit for air-conditioning a vehicle, and is used for compression of refrigerant circulating in the refrigeration circuit.
The scroll compressor includes a rear casing 10 and a front casing 12, and a scroll unit 14 is accommodated in the rear casing 10. The scroll unit 14 includes a fixed scroll 16 fixed to the rear casing 10 and a movable scroll 18 assembled to the fixed scroll 16.

  A discharge chamber 20 is formed in the rear casing 10 between its end wall and the fixed scroll 16 of the scroll unit 14. A discharge hole 24 is formed in the end wall 16 a of the fixed scroll 16, and a discharge chamber 20 can be connected to the discharge hole 24 via a reed valve type discharge valve 25, while a discharge port ( It is connected to the refrigerant circulation path of the refrigeration circuit via a not-shown).

The rear casing 10 is also formed with a refrigerant suction port (not shown). The suction port introduces the refrigerant into the rear casing 10 from the refrigerant circulation path, and the introduced refrigerant enters the scroll unit 14. Inhaled.
On the other hand, a drive shaft 26 is disposed in the front casing 12, and the drive shaft 26 has a large diameter end portion 28 and a small diameter shaft portion 30. The large diameter end portion 28 is rotatably supported by the front casing 12 via a needle bearing 32, and the small diameter shaft portion 30 is rotatably supported by the front casing 12 via a ball bearing 34. Further, a lip seal 36 is disposed between the small diameter shaft portion 30 and the front casing 12, and the lip seal 36 partitions the inside of the front casing 12 in an airtight manner.

  A small-diameter shaft portion 30 of the drive shaft 26 protrudes from the front casing 12, and the protruding end is connected to a drive pulley 38 incorporating an electromagnetic clutch. The drive pulley 38 is rotatably supported by the front casing 12 via a bearing 40. ing. The drive pulley 38 is connected to an output pulley on the engine side of the vehicle via a belt, and is rotated by receiving power from the engine. Therefore, during driving of the engine, if the electromagnetic clutch in the drive pulley 38 is on, the drive shaft 26 is rotated together with the drive pulley 38.

On the other hand, a crank pin 42 protrudes from the large-diameter end portion 28 of the drive shaft 26 toward the movable scroll 18, and the crank pin 42 supports a boss 48 of the movable scroll 18 via an eccentric bush 44 and a needle bearing 46. ing. Accordingly, when the drive shaft 26 is rotated, the movable scroll 18 performs a turning motion via the crank pin 42 and the eccentric bush 44.
More specifically, the fixed scroll 16 includes an end wall 16a and a fixed spiral body 60 formed integrally with the end wall 16a. The movable scroll 18 includes an end wall 18a facing the end wall 16a and the end wall 18a. And a movable spiral body 62 that is integrally formed. The inner and outer surfaces of the fixed and movable spiral bodies 60 and 62 are formed of involute curved surfaces except for the central end portion thereof, and fixed and movable tip seals 64 and 66 are formed at the spiral wrap ends of the fixed and movable spiral bodies 60 and 62. Are arranged.

  On the other hand, in each spiral space formed between the turns of the fixed and movable spiral bodies 60 and 62, spiral fixed side and movable side bottom plates 68 and 70 made of an abrasion-resistant material and having a predetermined plate thickness are provided. Each is arranged. The movable spiral body is moved relative to the stationary spiral body 60 while the movable and stationary chip seals 66 and 64, which are tip seals of the counterpart spiral body, are brought into sliding contact with the fixed and movable bottom plates 68 and 70, respectively. By cooperating with 62, a highly airtight compression chamber 71 is formed. The refrigerant compressed in the compression chamber 71 is discharged from the discharge hole 24 in the vicinity of the central end 60 a of the fixed spiral body 60. As described above, when the movable scroll 18 is swung with respect to the fixed scroll 16, the scroll unit 14 undergoes a series of processes from suction of refrigerant to compression and discharge of refrigerant from the discharge hole 24 of the fixed scroll 16. Run the process continuously.

In FIG. 1, reference numeral 50 indicates a counterweight for the movable scroll 18, and the counterweight 50 is attached to the eccentric bush 44.
Further, a rotation prevention coupling is disposed between the front casing 12 and the end wall 18 a of the movable scroll 18. In the case of this embodiment, the rotation prevention coupling comprises a so-called EM coupling 52, and the EM coupling 52 is configured by sandwiching a ball 58 between the annular race grooves of both the movable plate 54 and the fixed plate 56 each having a ring shape. ing.

Hereinafter, the positional relationship between the fixed side and movable side bottom plates 68 and 70 with respect to the end walls 16a and 18a will be described in order.
First, as shown in FIGS. 2 to 4, the fixed-side bottom plate 68 is slidably contacted with the movable tip seal 66 on the upper surface on the compression chamber 71 side to form a slidable contact surface 68b. The end wall 16a is in contact with the lower surface of the opposite side that is continuous with the thickness t1, and the contact surface 68c is formed. The fixed-side bottom plate 68 has a size that covers the swivel movement area when the movable tip seal 66 is brought into sliding contact with the sliding contact surface 68b as the movable scroll 18 turns. Further, the fixed-side bottom plate 68 does not close the discharge hole 24, and a certain clearance is secured between the central end 68 a of the fixed-side bottom plate 68 and the discharge hole 24.

  Referring to the enlarged view of the central end portion 60a of the fixed spiral body 60 shown in FIG. 3, there is no fixed-side bottom plate 68 in the vicinity of the central end portion 60a, and the end wall 16a around the discharge hole 24 is exposed. The exposed surface 16b is formed. As shown in FIG. 4, the exposed surface 16b is higher than the contact surface 68c on the slidable contact surface 68b side in a range not exceeding a predetermined plate thickness t1 of the fixed-side bottom plate 68.

  More specifically, in the exposed surface 16b, the sliding contact surface 68b is higher on the compression chamber 71 side by a step amount of α1 up to the sliding contact surface 68b. In other words, the end wall 16a is formed by increasing the plate thickness by a predetermined rising step amount (t1-α1) when viewed from the contact surface 68c. This step amount (t1-α1) is determined so that the movable tip seal 66 is in sliding contact with the sliding contact surface 68b in consideration of the tolerances of the thickness of the end wall 16a and the thickness t1 of the fixed bottom plate 68. The range is from the contact surface 68c to the sliding contact surface 68b.

  Thus, the end wall 16a in the vicinity of the center end portion 60a has the exposed surface 16b raised by the step amount (t1-α1), and the end wall 16a portion having the exposed surface 16b is fixed at the periphery. The spiral body 60 and the inner peripheral wall of the fixed bottom plate 68 are surrounded. Between the exposed surface 16b and the surface on which the movable tip seal 66 including the slidable surface 68b slides, and the exposed surface 16b, the slidable surface 68b and the exposed surface 16b have an area S1 excluding the opening area of the discharge holes. A space having a volume V1 = S1 · α1 multiplied by the step amount α1 of the exposed surface 16b is formed. Preferably, α1 = 0, that is, by making the rising step amount from the contact surface 68c the same as the plate thickness t1, the exposed surface 16b and the slidable contact surface 68b are flush with each other, and V1 = 0.

  Next, as shown in FIGS. 5 to 7, the movable-side bottom plate 70 has a sliding contact surface 70b of the fixed tip seal 64 and a contact surface 70c that contacts the end wall 18a, like the fixed-side bottom plate 68. The fixed tip seal 64 is slidably in contact with the slidable contact surface 70b so that the movable scroll can be turned. Preferably, the movable-side bottom plate 70 has the same shape as the fixed-side bottom plate 68, and can be diverted by changing the front and back.

  As shown in FIG. 6, the end wall 18a is exposed and raised by a step amount (t2-α2) at a location where the movable-side bottom plate 70 does not exist in the vicinity of the central end 62a of the movable spiral body 62. An exposed surface 18b is formed. Here, t2 is the thickness of the movable bottom plate 70, and α2 is the step amount between the sliding contact surface 70b and the exposed surface 18b. Further, as shown in FIG. 7, the step amount (t2−α2) is slidably contacted from the contact surface 70c so that the fixed chip seal 64 is slidably contacted with the slidable contact surface 70b in consideration of each plate thickness tolerance. It is determined appropriately so as to fall within the range up to the surface 70b.

  The end wall 18a portion having the exposed surface 18b is surrounded by the movable spiral body 62 and the inner peripheral wall of the movable side bottom plate 70, and forms a clearance therebetween. And between the surface where the fixed chip seal 64 including the sliding contact surface 70b slides and the exposed surface 18b, the area S2 of the exposed surface 18b is multiplied by the step amount α2 between the sliding contact surface 70b and the exposed surface 18b. A space having a volume V2 = S2 · α2 is formed. Preferably, α2 = 0, that is, by making the rising step amount from the contact surface 70c the same as the plate thickness t2, the exposed surface 18b and the slidable contact surface 70b are flush with each other, and V2 = 0.

  As described above, in the present embodiment, the end wall 16a of the fixed scroll 16 protrudes convexly by the step amount (t1-α1) on the exposed surface 16b. The volume is reduced by ΔV = S1 · (t1−α1) as compared to the case where the bulge is not raised, and becomes S1 · α1. Here, the refrigerant compressed in the compression chamber 71 is peeled off from the seal-off point (start point of the involute curved surface described above) at the central end 60a of the fixed spiral body 60, and then the pressure is reduced in the space having the volume of V1. V1 exists as a so-called dead volume. Therefore, by reducing the step between the exposed surface 16b and the sliding contact surface 68b, the dead volume is reduced by ΔV = S1 · (t1−α1), and the pressure drop of the refrigerant from the discharge hole 24 is reduced. This can reduce the compression efficiency of the compressor.

  Further, for the purpose of reducing the dead volume, it is not necessary to extend the tip of the center end portion 68a of the fixed-side bottom plate 68 in a sharp shape so as to wind the fixed spiral body 60. Thereby, the compression efficiency of the compressor can be improved while ensuring the strength of the fixed-side bottom plate 68 to ensure the reliability of the tip of the fixed-side bottom plate 68 and improving the workability.

  Further, the end wall 18a of the movable scroll 18 has an exposed surface 18b, and the movable spiral body 62 and the movable side bottom plate 70 have a clearance by an area S2 of the exposed surface 18b. Therefore, since the movable side bottom plate 70 is not formed so as to enclose all of the movable spiral body 62, the central end portion 70 a of the movable side bottom plate 70 comes into contact with the tip end of the central end portion 62 a of the movable spiral body 62 and the radius of curvature is increased. It will not be a large concave shape. Thereby, it is prevented that the front-end | tip of the center edge part 70a of the movable side bottom plate 70 becomes a sharp shape, and the lifetime of this press die improves.

  Furthermore, by setting α1 = α2 = 0, V1 = V2 = 0 and the dead volume is eliminated. Further, it is possible to ensure the reliability of the tip of the fixed-side bottom plate 68 and improve the workability, and to improve the durability of the press die of the movable-side bottom plate 70. Therefore, the compression efficiency of the compressor is greatly improved while improving the workability of the fixed side and movable side bottom plates 68 and 70.

Further, by making the fixed side and movable side bottom plates 68 and 70 the same shape, it is possible to reduce the cost by making the parts common, and it becomes easier to process and assemble the fixed side and movable side bottom plates 68 and 70. , Production efficiency is greatly improved.
Although the description of the embodiment of the present invention has been completed above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, both the end walls 16a and 18a of the fixed and movable scrolls 16 and 18 have the exposed surfaces 16b and 18b raised, respectively, but one of the end walls 16a and 18a is this. The other end wall may have a conventional end wall, that is, an end wall having an exposed surface that is not raised in the case of a fixed scroll, or an end wall that does not have an exposed surface in the case of a movable scroll. As long as either one has the raised exposed surface, the compression efficiency of the compressor can be improved while improving the strength and workability of the bottom plate.

It is sectional drawing which showed the scroll compressor. It is the top view which looked at the fixed scroll of FIG. 1 from II direction. FIG. 3 is an enlarged view of the vicinity of the center portion of FIG. 2. FIG. 4 is a cross-sectional view of FIG. 3. It is the top view which looked at the movable scroll of FIG. 1 from the V direction. It is an enlarged view of the center part vicinity of FIG. It is sectional drawing of FIG.

Explanation of symbols

16 fixed scroll 16a end wall 16b exposed surface 18 movable scroll 18a end wall 18b exposed surface 24 discharge hole 60 fixed spiral body 62 movable spiral body 68 fixed side bottom plate 68b sliding surface 68c abutting surface 70 movable side bottom plate 70b sliding contact Surface 70c contact surface 71 compression chamber

Claims (3)

An end wall having a discharge hole, and a fixed scroll having a fixed spiral formed integrally with the end wall;
A movable scroll having an end wall opposite to the end wall, and a movable spiral body that is integrally formed with the end wall and discharges the working fluid from the compression chamber formed in cooperation with the fixed spiral body from the discharge hole. When,
A spiral fixed bottom plate having a sliding contact surface that is slidably contacted with the movable spiral body and a contact surface that is in contact with the end wall of the fixed scroll with a predetermined thickness from the sliding contact surface When,
A spiral movable bottom plate having a sliding surface that is in sliding contact with the fixed spiral body, and a contact surface that is in contact with the end wall of the movable scroll with a predetermined thickness from the sliding contact surface And
The end wall of at least one of the fixed and movable scrolls is exposed to the compression chamber and has a predetermined plate thickness from the contact surface that contacts the same end wall to the contact surface. A scroll compressor having an exposed surface positioned within a range up to the slidable contact surface.   The scroll compressor according to claim 1, wherein the exposed surface is positioned flush with the sliding contact surface.   The scroll compressor according to claim 1 or 2, wherein the fixed side and movable side bottom plates have the same shape.

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