Interfitting mechanism of spiral elements for scroll type fluid displacement apparatus

Abstract

 A scroll type fluid displacement apparatus (10), a method of assembling the apparatus (10), and an adjustment member (40) for use in the assembly method are disclosed. The apparatus (10) includes a front end plate (11) through which a hole extends (113), a hole (214) formed in end plate (211) of orbiting scroll (21), and a indentation (206) formed in a fixed scroll (20). The adjustment member (40) is inserted through the hole (113) and extends into the hole (214) of orbiting scroll (21) and indentation (206) of fixed scroll (20). Then, the front end plate (11) is rotated toward the undriving direction end a drive shaft (13) is rotated toward the driving direction with a predetermined torque. Therefore, the angular relationship between both scroll (20, 21) is adjusted.

Description

[0001] This invention relates to a fluid displacement apparatus, and more particularly, to an adjusting mechanism of angular relationship between spiral elements for a scroll type fluid displacement apparatus.

[0002] Scroll type fluid displacement apparatus are well known in the prior art. For example, U.S. Patent No. 801,182 (Creux) discloses a device including two scroll members each having a circular end plate and a spiroidal or involute spiral element. These scroll members are maintained angularly and radially offset so that both spiral elements interfit to make a plurality of line contacts between their spiral curved surfaces to thereby seal off and define at least one pair of fluid pockets. The relative orbital motion of the two scroll members shifts the line contacts along the spiral curved surfaces and, therefore, the fluid pockets change in volume. Since the volume of the fluid pockets increases or decreases dependent on the direction of the orbiting motion, the scroll type fluid displacement apparatus is applicable to compress, expand or pump fluids.

[0003] In comparison with conventional compressors of the piston type, the- scroll type compressor has certain advantages, such as fewer parts and continuous compression of fluid. However, scroll type compressors has the problem that adjusting of angular relationship between the spiral elements is difficult and operation. If the angular relationship between spiral element is in error, a radial sealing points between two spiral elements are resolved to causes the fluid leakage. As a result of the fluid leakage, a efficiency of the compressor does not reach the predetermined volume. One solution to resolved the above problem is reduced error of parts. However, the manufacturing of the parts is complicated and spend much cost. Further solution to resolved the problem is method to indirectly the limits of holerale maintained the angular relationship between the both spiral elements. However, since these methods have many factors which cause the unsuitable angular relationship, these methods can not become the final solution.

[0004] Particularly, during the assembly of compressor which has the ball coupling mechanism, relative angular offset between the both scroll members is occured due to the following factors ;

(1) the relative angular offset between the fixed scroll element and housing;

(2) the relative angular offset between the housing and the front end plate;

(3) the relative angular offset between the front end plate and the fixed ring of ball coupling mechanism;

(4) the relative angular offset caused by the difference of the inner diameter of hole formed in fixed ring of ball coupling mechanism from the outer diameter of ball;

(5) the relative angular offset caused by the difference of the outer diameter of ball from the inner diameter of hole formed in movable ring of the ball coupling mechanism; and

(6) the relative angular offset between movable ring of the ball coupling mechanism and orbiting scroll member.

[0005] In order to solve these factors, one technique to adjust the angular relationship is provided that the hole is formed on the end wall surface of spiral element of one scroll member, and the hole in formed through the front end plate opposite to said hole of the scroll member. The adjusting of angular relationship between both scroll elements is operated by angle adjusting member inserted in the both holes from outside of the front end plate.

[0006] However, the above techniques can solve only the above- mentioned factors of the relative angular offset (1)-(3), the remained factors of the relative angular offset (4)-(6) can not be solved.

[0007] It is a primary object of this invention to provide an efficient scroll type fluid displacement apparatus.

[0008] It is another object of this invention to provide a scroll type fluid displacement apparatus wherein the angular relationship between both scroll members is easily and exactly established.

[0009] It is still another object of this invention to realize the above objects with a simple construction and assembly technique.

[0010] According to the present invention there is provided in a scroll type fluid displacement apparatus including a first scroll member having a first end plate from which a first spiral element extends, a second scroll member having a second end plate from which a second spiral element extends, said first and second scroll members interfitting at an angular and radial offset to make a plurality of line contacts to define at least one pair of sealed off fluid pockets, a driving mechanism operatively connected to said second scroll member to effect the orbital motion of said second scroll member while the rotation of said second scroll member prevented by a rotation preventing/thrust bearing mechanism, whereby the fluid pockets change volume, the improvement comprises, said first scroll member being formed with a bore having a predetermined depth, said second end plate of second scroll member formed through a penetrating hole, said front end plate having a hole extending completely through to be substantial alignment with said bore and penetrating hole by adjusting member inserted into bore and penetrating hole through said hole of front end plate during assembly of the apparatus to set the angular relationship between both scroll members.

[0011] One embodiment of the invention includes a housing having a front end plate, and a pair of scroll members. One of the scroll members is fixedly disposed relative to the housing and has an end plate from which a first wrap extends into the interior of the housing. The other scroll member is movably disposed for non-rotative orbital movement within the interior of the housing and has an end plate from which a second wrap extends. The first and second wraps interfit at an angular and radial offset to make a plurality of line contacts to define at least one pair of sealed off fluid pockets. A driving mechanism is operatively connected to the other scroll member to effect its orbital motion, whereby the fluid pockets move and change volume. The fixed scroll member is formed with a bore which has predetermined depth, and the front end plate of the housing is formed with a hole extending completely through it. The hole is adapted to be aligned with the bore by an adjustment member which extends through it into the bore during the assembly of the apparatus to set the angular relationship between the two scroll members.

[0012] The present invention is also directed to the structure of the adjustment member per se, and to a method for assembling the scroll type fluid displacement apparatus.

[0013] The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a vertical sectional view of a scroll type compressor according to one embodiment of this invention;

Figure 2 is an exploded perspective view of a driving mechanism for an orbiting scroll used in the compressor of Figure 1;

Figure 3 is an exploded perspective view of a rotation preventing/thrust bearing mechanism for an orbiting scroll used in the compressor of Figure 1;

Figure 4 is a diagrammatic view of fixed scroll illustrating the position of indentation.

[0014] Referring to Figure 1, an embodiment of a scroll type fluid displacement apparatus is accordance with the present invention, in particular as scroll type refrigerant compressor is shown. The compressor includes a compressor housing 10 having a front end plate 11 and a cup shaped casing 12 fastened on the rear end surface of front end plate 11. An opening 111 is formed in the center of front end plate 11 for penetration or passage of a drive shaft 13. An opening portion of cup shaped casing 12 is covered by front end plate 11, and mating surface between front end plate 11 and cup shaped casing 12 is sealed by an O-ring 14. Front end plate 11 has an annular sleeve 15 projecting from the front end surface thereof which surrounds drive shaft 13 and defines a shaft seal a cavity.

[0015] Drive shaft 13 is rotatably supported by sleeve 15 through a bearing 16 located within the front end of sleeve 15. Drive shaft 13 has a disk shaped rotor 131 at its inner end which is rotatably supported by front end plate 11 through a bearing 17 located within opening 111 of front end plate 11.

[0016] A number of elements is disposed within the interior of cup shaped casing 12 including a fixed scroll 20, an orbiting scroll 21, a driving mechanism for orbiting scroll and a rotation preventing/thrust bearing mechanism 22 for orbiting scroll 21. The interior of cup shaped casing 12 is defined between the inner wall of cup shaped casing 12 and the rear end surface of front end plate 11.

[0017] Fixed scroll 20 includes a circular end plate 201, a wrap or spiral element 202 affixed to or extending from one side surface of circular end plate 201 and a plurality of internally threaded bosses 203 axially projecting from the other side surface of circular end plate 201. An axial end surface of each bosses 203 is seated on the inner surface of end plate 121 of cup shaped casing 12 and is fixed to end plate 121 by bolts 23. Fixed scroll 20 is thus fixed within cup shaped casing 12. Circular end plate 201 of fixed scroll 20 partitions the inner chamber of cup shaped casing 12 into two chamber, such as discharge chamber 24 having bosses 203, and a suction chafer 25 in which spiral element 202 is located. A seal ring 26 is placed between the outer peripheral surface of circular end plate 201 and the inner surface of cup shaped casing 12 to secure the sealing therebetween. A hole or discharge port 204 is formed through circular end plate 201 of fixed scroll 20 at a position near the center of spiral element 202; hole 204 is connected between the fluid pocket of the spiral elements center and discharge chamber 24.

[0018] Orbiting scroll 21, which is disposed in suction chamber 25, comprises a circular end plate 211 and a wrap or spiral element 212 affixed to or extending from one side surface of end plate 211. The spiral element 212 of orbiting scroll 21 and spiral element 202 interfit at an angular offset of 180° and predetermined radial offset to make a plurality of line contacts. Therefore, at least one pair of sealed off fluid pockets are defined between their spiral elements 202 and 212. Orbiting scroll 21 is connected to the driving means and rotation preventing/thrust bearing means 22. These lastest two means effect the orbital motion of orbiting scroll 21 by rotation of drive shaft 13.

[0019] Referring to Figures 1 and 2, the driving mechanism of orbiting scroll 21 will be described. Drive shaft 13 is formed with a disk shaped 131 at its inner end and is rotatably supported by sleeve 15 through a bearing 16 which is disposed within sleeve portion 15. D sk shaped portion 11 through bearing 17.

[0020] A crank pin or drive pin 132 projects axially from an end surface of disk portion 131 and is radially offset from the center of drive shaft 13. Circular plate 211 of orbiting scroll 21 is provided with a tubular boss 213 axially projecting from an end surface opposite to the side thereof from which spiral element 212 extends. A discold or short axial bushing 27 is fitted into boss 213, and is rotatably supported therein by a bearing, such as a needle bearing 28. Bushing 27 has a balance weight 271 which is shaped as a portion of a disk or ring and extends radially outward from bushing 27 along a front surface thereof. An eccentric hole 272 is formed in bushing 27 radially offset from the center of bushing 27. Drive pin.132 is fitted into the eccentrically disposed hole 272 within which a bearing 29 may be applied. Bushing 27 is therefore driven by the revolution of drive pin 132 and is permitted to rotate by needle bearing 28.

[0021] Referring to Figure 3, the rotation preventing/thrust bearing device 22 will be described. Rotation preventing/thrust bearing device 22 is disposed between the rear end surface of front end plate 11 and the end surface of circular end plate 211 of orbiting scroll 21 on the side opposite spiral element 212. Rotation preventing/thrust bearing device 22 includes a fixed portion, an orbital portion and a bearing element, such as a plurality of spherical balls.

[0022] The fixed portion includes an annular fixed race 221 having one end surface fitted against the axial end surface of an annular projection of front end plate 11, and a fixed ring 222 fitted against the other axial end surface of fixed race 221. Fixed race 221 and fixed ring 222 are attached to the axial end surface of annular projection by pins 223.

[0023] The orbital portion also includes an annular orbital race 224, which has one end surface fitted against an axial end surface of circular end plate 221, and an orbital ring 225 fitted against the other axial end surface of orbital race 224 to extend outwardly therefrom and cover the other axial end surface of orbital race 224. A small clearance is maintained between the end surface of fixed ring 222 and the end surface of orbital ring 225. Orbital race 224 and orbital ring 225 are attached to the end surface of circular end plate 211 by pins 226. Alternatively, rings 222, 225 may be formed integral with races 221, 224, respectively.

[0024] Fixed ring 222 and orbital ring 225 each have a plurality of holes or pockets 222a and 225a in the axial direction, the number of holes or pockets in each of rings 222 and 225 being equal. The holes or pockets 222a on fixed ring 222 correspond to or are a mirror image of the holes or pockets 225a on orbital ring 225; i.e., each pair of pockets facing each other have the same size and pitch, and the radial distance of the pockets from the center of their respective rings 222 and 225 is the same; i.e., the centers of the pockets are located the same distance from the center of rings 222 and 225. Thus, if the centers of rings 222 and 225 were aligned, which they are not in actual operation of the rotation preventing/thrust bearing device 22, the holes or pockets 222a and 225a would be identical or in alignment. Bearing elements, such as balls 227, are placed between facing generally aligned pairs of pockets 222a and 225a of fixed and orbital rings 222, 225 with the rings 222, 225 facing one another at a predetermined clearance.

[0025] In this construction of scroll type compressor, fixed scroll 20 is at least provided with a projection 205 projecting from the outer surface of spiral element 202, and preferably integral with it. A round bore 206, which has predetermined depth, is formed in projection 205 of fixed scroll 20. As shown in Figure 4, round bore 206 is placed on a line drawn through a center of generating circule of the spiral element which has a predetermined angule relative to a line connected through a plurality of line contacts A, B between the spiral element 202 and 212. Circular end plate 211 of orbiting scroll 21 is formed through a penetrating hole 214. Front end plate 11 is also formed with a round hole 113. Hole l13 is designed to be aligned with bore 206 and penetrating hole 214, in a manner described herein after. A part of fixed ring 221 of rotation preventing/thrust bearing mechanism 22 which extends over the end of annular projection to cover hole 113 may be formed with a cut portion 221C. Hole l13 has a diameter larger than the diameter of bore 206 and penetrating hole 214.

[0026] With this arrangement, assembly of the compressor is accomplished by the following method. Fixed scroll 20 is fixed within the interior of cup shaped casing 12 by bolts 23. The driving mechanism of orbiting scroll 21, orbiting scroll 21 and a part of rotation preventing/thrust bearing mechanism 22 are assembled on front end plate 11. Then, front end plate 11 is placed in the opening portion of cup shaped casing 12 to close it. At this time, an adjustment member 40 is inserted through hole 113, penetrating hole 214 and into bore 214.

[0027] After inserted adjustment member 40, front end plate 11 is rotated coward the undriving direction to interact ball 227 between facing pockets 222a and 225a. Because, during the operation of the apparatus ball 227 of rotation preventing/thrust bearing mechanism 22 is usually interacted between the edge of both pockets 222a and 225a without gap to prevent the rotation of orbiting scroll 21, thereby the formal angular relationship between fixed ring 222 and orbiting scroll 21 is determined. Then, drive shaft 13 is rotated toward the driving direction due to a predetermined torque to rotate spiral element 212 of orbiting scroll 21 around adjustment member 40 to push spiral element 212 against spiral element 202 of fixed scroll 20. At this operation, orbiting ring 225 is fixed on end plate 211 of orbiting scroll 21, therefore orbiting ring 225 is rotated together with orbiting scroll 21. Since, ball 227 of rotation preventing/thrust bearing mechanism 22 is interacted between the edge of both pockets, fixed ring 222, hence front end plate 11 is rotated toward the driving direction following with the rotation of orbiting scroll 21. Thus, the relationship between both scroll 20, 21 and rotation preventing mechanism 22 and orbiting scroll 21 are set up the operating condition of the compressor.

[0028] The angular relationship between both scrolls, can therefore be adjusted and set by above mentioned operation. After the predetermined desired offset between the scroll is aligned, adjustment member 40 is removed from compressor unit. The offset between the scroll is fixed by tightening the fastening means. A plug 41 is screwed into a screw portion l13a of hole 113, add seal ring 42 is disposed within an annular depression 113b formed at end portion of hole l13 to form a seal between plug 41 and hole 113 to seal off the inner chamber of cup shaped casing 12.

[0029] This invention has been described in detail in connection with a preferred embodiment, but this embodiment is merely for example only and this invention is not restricted thereto. It will be easily understood by those skilled in the art that other variations and modifications can be easily made within the scope of this invention, as defined by the appended claims.

Claims

1. In a scroll type fluid displacement apparatus including a first scroll member having a first end plate from which a first spiral element extends, a second scroll member having a second end plate from which a second spiral element extends, said first and second scroll members interfitting at an angular and radial offset to make a plurality of line contacts to define at least one pair of sealed off fluid pockets, a driving mechanism operatively connected to said second scroll member to effect the orbital motion of said second scroll member while the rotation of said second scroll member prevented by a rotation preventing/ thrust bearing mechanism, whereby the fluid pockets change volume, the improvement comprises, said first scroll member being formed with a bore having a predetermined depth, said second end plate of second scroll member formed through a penetrating hole, said front end plate having a hole extending completely through to be substantial alignment with said bore and penetrating hole by adjusting member inserted into bore and penetrating hole through said hole of front end plate during assembly of the apparatus to set the angular relationship between both scroll members.

2. The scroll type f3uid displacement apparatus of claim 1 wherein said bore and penetrating hole have a diameter smaller than said hole of front end plate.

3. The scroll type fluid displacement apparatus of cliam 1 wherein said indentation is placed on a line drawn through a center of generating circul of said spiral element with a predetermined angle against to a line passing through a plurality of the line contacts defined between said both spiral elements.

4. A method for assembling a scroll type fluid displacement apparatus comprising the steps of:

(a) fixing a casing having at least one opening portion about a fixed scroll member having a circular end plate from which a first wrap extends:

(b) assembling a driving mechanism and an orbiting scroll member operatively connected to the driving mechanism on a front end plate;

(c) placing the front end plate into the opening portion of the casing;

(d) inserting an adjusting member into a bore formed in the fixed scroll member and a penetrating hole formed through the circular end plate of fixed scroll member through a hole which is formed through the front end plate from out side of the front end plate;

(e) rotating the front end plate to undriving direction untill the front end plate prevented the movement;

(f) rotating the drive shaft with predetermined torque;

(g) securely fixing the front end plate to the casing; and

(h) closing an open portion of the hole.

Drawing