Apparatus for casting scroll member and method of manufacturing scroll member

Abstract

An apparatus for casting a scroll member of a compressor has a first die and a second die. The first die includes a molding surface for molding a base plate of the scroll member. The second die includes a molding surface for molding a scroll wall of the scroll member. The first and second dies define a cavity for casting the scroll member. The first die also includes a first die-member and a second die-member. The second die-member forms a portion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second dies separate from each other.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an apparatus for casting a scroll member for use in a compressor and a method of manufacturing a scroll member.

[0002] One of compressors used in a refrigerant circuit of a vehicle is a scroll type. The scroll type compressor generally accommodates a fixed scroll member and a movable scroll member in its housing. The fixed scroll member includes a base plate and a scroll wall, while the movable scroll member includes a base plate and a scroll wall. The scroll walls of the fixed and movable scroll members are engaged with each other.

[0003] Compression chambers are defined between the scroll walls. The compression chambers radially inwardly move from the peripheral side of the scroll walls toward the center of the scroll walls by orbiting the movable scroll member with respect to the central axis of the fixed scroll member, thus gradually compressing gas introduced from an outside.

[0004] In such a structure mentioned above, as the compression chambers move, the volumes of the compression chambers reduce, thus compressing refrigerant gas. Therefore, ensuring sealing performance around the compression chambers is important.

[0005] The movable and fixed scroll members are manufactured by die-casting, which is one of moldings. As shown in FIGS. 3A and 3B, when the movable scroll member is cast in a mold, a casting apparatus 55 provides a cope 43 and a drag 33 on its center. The cope 43 is a die for casting a scroll wall of a scroll member 50, while the drag 33 is a die for casting a base plate of the scroll member 50. The cope 43 and the drag 33 define a cavity 36 for casting by fitting the cope 43 to the drag 33. A molten metal is filled in the cavity 36 between the cope 43 and the drag 33, and is cooled. The cast scroll member 50 is taken off out of the cope 43 and the drag 33 after the molten metal solidifies. Besides, as a matter of convenience, the scroll member 50 is indicated by hatching in FIGS. 3A and 3B.

[0006] When the scroll member 50 is taken off out of the cope 43 and the drag 33, extruding plungers 45 provided in the cope 43 push the end 50a of the scroll wall and extrude the scroll wall synchronously with separating the cope 43 from the drag 33. Additionally, extruding plungers 35 provided in the drag 33 extrude the base plate of the movable scroll member.

[0007] When the scroll member 50 is taken off by the above-mentioned extruding plungers 35, 45, the scroll member 50 is die-cast with the extruding plungers 35, 45 being movably inserted in plunger holes 34, 44, which are formed in the drag 33 and the cope 43, respectively. Therefore, incorrect positioning, abrasion and deformation of the extruding plungers 35, 45 cause the shape of the ends of the extruding plungers 35, 45 to be diverse, and cause the length of the extruding plungers 35, 45 to be unequal. Consequently, after casting, rough marks due to the extruding plungers 35, 45 remain on the end 50a of the scroll wall of the scroll member 50. Namely, when the extruding plungers 45 protrude from the molding surface of the cope 43, recesses are formed on the end 50a of the scroll wall. When the extruding plungers 45 recede from the molding surface of the cope 43, protrusions are formed on the end 50a of the scroll wall. Also, when the scroll member 50 is taken off, the extruding plungers 45 push the thin end 50a of the scroll wall. Thereby, the scroll wall slightly deforms.

[0008] Due to such recess, protrusion and deformation, when the fixed and movable scroll members define the compression chambers, gaps between the end 50a of the scroll wall and the facing surface of the end 50a based on the recess and the protrusion exceed a permissible range, and another gaps are also defined between the scroll walls. Thereby, the refrigerant gas undesirably leaks. Accordingly, to ensure the sealing performance around the compression chambers, the end 50a of the scroll wall of the scroll member 50 and the surface of the scroll wall are required to be uniform by machining. Thereby, the process of manufacturing the scroll member 50 increases.

SUMMARY OF THE INVENTION

[0009] The present invention addresses the above-mentioned problems by improving a die for casting a scroll member

[0010] According to the present invention, an apparatus for casting a scroll member of a compressor has a first die and a second die. The first die includes a molding surface for molding a base plate of the scroll member. The second die includes a molding surface for molding a scroll wall of the scroll member. The first and second dies define a cavity for casting the scroll member. The first die also includes a first die-member and a second die-member. The second die-member forms a portion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second dies separate from each other.

[0011] The present invention also provides a method of manufacturing a scroll member, including a base plate and a scroll wall, by a die having a first part including a molding surface for the scroll wall, a second part including a molding surface for the base plate, and a third part including a molding surface to form a protrusion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second parts separate from each other. The method includes casting the scroll member in the die, separating the first part from the second and third parts while the third part engages with the protrusion, disengaging the third part from the protrusion, and separating the scroll member from the second part.

[0012] Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

[0014] FIG. 1A is a schematic cross-sectional view of an apparatus for casting a scroll member of a compressor in a state of fitting a cope to a drag according to an embodiment of the present invention;

[0015] FIG. 1B is a schematic cross-sectional view of an apparatus for casting a scroll member of a compressor in a state of separating a cope from a drag according to the embodiment of the present invention;

[0016] FIG. 1C is a schematic cross-sectional view of an apparatus for casting a scroll member of a compressor in a state of extruding a scroll member from a cope according to the embodiment of the present invention;

[0017] FIG. 2A is a top plan view of a cope according to the embodiment of the present invention;

[0018] FIG. 2B is a cross-sectional view taken along the line 1-1 in FIG. 2A;

[0019] FIG. 2C is an enlarged partial cross-sectional view of FIG. 2B;

[0020] FIG. 3A is a schematic cross-sectional view of an apparatus for casting a scroll member of a compressor in a state of fitting a cope to a drag according to a prior art; and

[0021] FIG. 3B is a schematic cross-sectional view of an apparatus for casting a scroll member of a compressor in a state of separating a cope from a drag according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of the present invention will now be described with reference to FIGS. 1A through 2C. A casting apparatus 25 shown in FIG. 1A is used for casting a scroll member 20 for use in a scroll type compressor. The scroll member 20 described in the present embodiment is a movable scroll member.

[0023] The casting apparatus 25 includes a fixed installation seat 1 at its lower side, and the fixed installation seat 1 provides a drag 3 as a first part including a molding surface for casting a scroll wall of the scroll member 20 and a molding surface for casting the surface of a base plate of the scroll member adjacent to the scroll wall. The casting apparatus 25 also includes a movable installation seat 11 at its upper side, and the movable installation seat 11 connects with a cylinder actuator or another reciprocating actuator as a driving apparatus, which is not shown, for operating the movable installation seat 11. Also, the movable installation seat 11 provides a cope 13 as a die including a molding surface for casting the base plate of the scroll member 20 through a stay 12.

[0024] Thereby, the movable installation seat 11 operatively moves up and down by the driving apparatus, so that the cope 13 can approach and leave from the drag 3. Also, the cope 13 forms a plurality of plunger holes 14, and the lower ends of the plunger holes 14 extend to a cavity 6, which is defined by the cope 13 and the drag 3. Extruding plungers 15 each extend through the plunger holes 14. One ends of the extruding plungers 15 are secured to an extruding plate 16, which is positioned between the movable installation seat 11 and the cope 13. The one ends of the extruding plungers 15 recede from and protrude into the cavity 6 by moving the extruding plate 16 up and down, respectively. The extruding plate 16 moves up and down by operating a cylinder actuator 19 or another reciprocating actuator as a driving apparatus

[0025] As shown in FIGS. 2A through 2C, the scroll member 20 manufactured by the casting apparatus 25 is constituted of a base plate 21 and a scroll wall 22. The base plate 21 provides a boss 32 on the side opposite to the scroll wall 22. Besides, the plunger holes 14 are formed in the cope 13, and the extruding plungers 15 extend the plunger holes 14 through. The plunger holes 14 and the extruding plungers 15 are not shown.

[0026] The cope 13, which is the die including the molding surface for casting the base plate 21, includes a first molding surface 31a for molding the base plate 21. The first molding surface 31a forms a disk-shaped cavity, which provides a plurality of recesses 37a (three recesses in the present embodiment) in equiangular positions on its outer periphery. The recesses 37a are trapeziform in shape, as seen from the upper side of the cope 13. The recesses 37a extend in a direction B, which is perpendicular to a direction in which the cope 13 and the drag 3 separate from each other or perpendicular to a direction A. The direction A is a vertical direction in the present embodiment.

[0027] The cope 13 also includes a second molding surface 32a for casting the boss 32. The second molding surface 32a forms a cylindrical cavity, which also provides a plurality of trapeziform recesses 38a (three recesses in the present embodiment) in equiangular positions on its outer periphery, as well as the recesses 37a. Protrusions 37, 38 are formed in the recesses 37a, 38a by casting, respectively.

[0028] The cope 13 includes a main die 13a as a first die-member and a second part and a plurality of sub dies 13b as a second die-member and a third part (three in the present embodiment). The main die 13a, which does not includes the recesses 37a, 38a, operates in the direction A. The sub dies 13b, which includes the recesses 37a, 38a, operate in the direction B perpendicular to the direction A and in a radial direction with respect to the central axis of the scroll member 20.

[0029] Meanwhile, the drag 3, which is the die including the molding surface for casting the scroll wall 22 of the scroll member 20, includes a third molding surface 22a for molding the scroll wall 22. The third molding surface 22a forms a scroll-shaped cavity. The cavity 6, which forms the scroll member 20, is defined by fitting the cope 13 to the drag 3.

[0030] In the above-described casting apparatus 25, the cavity 6 provides drafts θ in various portions so as to separate the scroll member 20 from the dies smoothly. As shown in FIG. 2, the second molding surface 32a of the cope 13 provides drafts θ on surfaces for casting the inner and outer circumferential walls of the boss 32. Also, the third molding surface 22a of the drag 3 provides drafts θ on surfaces for casting the inner and outer circumferential walls of the scroll wall 22. The recesses 37a, 38a of the sub dies 13b provide drafts θ on its upper and lower surfaces and both sides, respectively. The inclinations of the drafts θ are determined based on difficulty in separating the scroll member 20 from the dies and a required leave for machining after casting.

[0031] In FIG. 1, the sub dies 13b each connect with cylinder actuators or other reciprocating actuators, which are not shown, for operating the sub dies 13b, and the cylinder actuators or other reciprocating actuators are arranged on the movable installation seat 11. As the cylinder actuators or other reciprocating actuators each reciprocate, the sub dies 13b each move in the respective directions B. Namely, the cylinder actuators or other reciprocating actuators for operating the sub dies 13b are arranged so as to reciprocate in the respective directions B perpendicular to the direction A.

[0032] The operation of the casting apparatus 25 constructed above will now be described. As shown in FIG. 1A, the cope 13 is formed by fitting the sub dies 13b to the main die 13a.

[0033] As the driving apparatus operates, the cope 13 with the movable installation seat 11 moves downwardly. Thereby, the cope 13 fits onto the drag 3, thus defining the cavity 6. Heated molten metal passes through a gate, which is formed through the drag 3, and the molten metal is forced into the cavity 6 including the recesses 37a, 38a by operating a plunger for injecting the molten metal. The gate and the plunger are not shown. Meanwhile, the end of the extruding plungers 15 extend to the bottom openings of the plunger holes 14, and close the plunger holes 14 to define the cavity 6

[0034] The cope 13 and the drag 3 are cooled by cooling water flowing through a cooling pipe, which extends in the cope 13 and the drag 3. Thereby, the molten metal injected into the cavity 6 is efficiently cooled and solidified. In a practical manufacturing process, the molten metal is cooled and solidified for about a minute.

[0035] As shown in FIG. 1B, the movable installation seat 11 moves upwardly after the molten metal solidifies, and the cope 13 leaves from the drag 3, thus starting separating the scroll member 20 from the dies. Meanwhile, since the cylinder actuators or other reciprocating actuators, which are not shown, for operating the sub dies 13b are arranged on the movable installation seat 11 and connect with the sub dies 13b, the sub dies 13b integrally move upwardly with the movable installation seat 11. Also, since the sub dies 13b each engage with the protrusions 37, 38 formed in the recesses 37a, 38a, the base plate 21 is lifted up from the drag 3 by moving the cope 13 including the sub dies 13b upwardly. The base plate 21 is easily separated from the drag 3 due to the drafts θ of the scroll wall 22.

[0036] As shown in FIG. 1C, the sub dies 13b moves in the direction B perpendicular to the direction A and in the radial direction with respect to the central axis of the scroll member 20, thus separating the sub dies 13b from the protrusions 37, 38.

[0037] Meanwhile, the cylinder actuator 19 or other reciprocating actuator operates, and the extruding plungers 15 protrude. Thereby, the base plate 21 is force out, and leaves from the main die 13a.

[0038] Since a robot arm 39 extends to a space between the cope 13 and the drag 3 preceded the separation of the base plate 21 from the main die 13a, the robot arm 39 receives the scroll member 20, and finally carries the scroll member 20 to a next process.

[0039] In the scroll member 20 manufactured as described above, the end 20a of the scroll wall 22 does not provide any recesses and protrusions as those in the conventional casting apparatus 55. The base plate 21 provides recesses and protrusions on a surface opposite to the scroll wall 22. However, the surface opposite to the scroll wall 22 may be machined, and the recesses and protrusions may disappear. Even if the recesses and protrusions are left as it is, the condition of the surface does not affect the operation of the scroll member 20 in a state that the scroll member 20 is assembled to a compressor. Additionally, upon separating the scroll member 20 from the dies, the extruding plungers 15 push the thick flat base plate 21. Therefore, the scroll member 20 hardly deforms. If the protrusions 37, 38 are used for assembling the scroll member 20, or are available in operating the scroll member 20, the protrusions 37, 38 may be left. Basically, the protrusions 37, 38 are removed by machining.

[0040] The following advantageous effects are obtained from the present embodiment.

[0041] (1) According to the casting apparatus 25 described above, the end 20a of the scroll wall 22 of the scroll member 20 does not provide any recesses, any protrusions and any deformations as those by a plurality of the extruding plungers 45 in the conventional casting apparatus 55, and the surface of the end 20a is flat, thereby reducing or cutting a process for machining the end 20a and the wall surface of the scroll wall 22 of the scroll member 20. Accordingly, time and process of manufacturing may be reduced as compared with conventional time and process of manufacturing.

[0042] (2) Since the end 20a of the scroll wall 22 of the scroll member 20 provides the drafts θ, the scroll member 20 is easily separated from the dies. Therefore, molded surface, so-called a mill scale, which performs relatively high durability and abrasion resistance, remains without any recesses, any protrusions and any deformations, and is used as it is.

[0043] The embodiment described above may be modified into the following examples.

[0044] In the embodiment described above, the scroll member 20 is separated from the dies in order of the scroll wall 22, protrusions 37, 38, and the base plate 21. However, the order of the separation is not limited to it. For example, the scroll member 20, which is separated from the dies in order of the scroll wall 22, the base plate 21, and protrusions 37, 38, is also applied. In such a state, in case the sub dies 13b do not integrally move upwardly with the movable installation seat 11, an additional driving apparatus for moving the sub dies 13b upwardly is required in addition to the cylinder actuators or other reciprocating actuators for moving the sub dies 13b in the respective directions B.

[0045] The number of the divided pieces of the cope 13 and the shape of the cope 13 are not limited to the embodiment described above. Not hindering the main die 13a and the sub dies 13b, which constitute the cope 13, from separating from each other, any structure may be applied.

[0046] In the embodiment described above, the cope 13 and the drag 3 are vertically disposed. However, the cope 13 and the drag 3 may be disposed horizontally.

[0047] In the embodiment described above, the driving apparatus for operating the cope 13 is the cylinder actuator or other reciprocating actuator. However, the driving apparatus is not limited to it. For example, a robot arm may be substituted for the cylinder actuator or other reciprocating actuator.

[0048] In the embodiment described above, the scroll member is used in a compressor for an air conditioner of a vehicle. However, the scroll member may be used in another compressor other than the compressor for the air conditioner of the vehicle as far as the compressor is a scroll type.

[0049] According to the present invention, since the end of the scroll wall of the scroll member cast by the casting apparatus ensures a flat end surface, the time and process for machining the end surface of the scroll wall is reduced or cut.

[0050] Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.

Claims

1. An apparatus for casting a scroll member of a compressor, the apparatus comprising: a first die including a molding surface for molding a base plate of the scroll member; a second die including a molding surface for molding a scroll wall of the scroll member, the first and second dies defining a cavity for casting the scroll member; and wherein the first die comprises a first die-member and a second die-member, the second die-member forms a portion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second dies separate from each other.

2. The apparatus for casting the scroll member of the compressor according to claim 1, wherein the first die-member operates in the direction in which the first and second dies separate from each other, and the second die-member operates in a direction in which the portion extends.

3. The apparatus for casting the scroll member of the compressor according to claim 1, wherein the portion is a protrusion.

4. The apparatus for casting the scroll member of the compressor according to claim 1, wherein the number of the second die-member is three or more.

5. The apparatus for casting the scroll member of the compressor according to claim 4, wherein the number of the second die-member is three.

6. The apparatus for casting the scroll member of the compressor according to claim 1, wherein a driving apparatus for operating the first die-member is a reciprocating actuator.

7. The apparatus for casting the scroll member of the compressor according to claim 6, wherein a driving apparatus for operating the first die-member is a cylinder actuator.

8. An apparatus for casting a scroll member of a compressor, the apparatus comprising: a first die including a molding surface for molding a base plate of the scroll member; a second die including a molding surface for molding a scroll wall of the scroll member and a molding surface for molding the surface of the base plate, the first and second dies defining a cavity for casting the scroll member; and wherein the first die comprises a first die-member and a second die-member, the second die-member forms a portion of the scroll member, which extends in a direction substantially in parallel with the molding surface for molding the surface of the base plate.

9. The apparatus for casting the scroll member of the compressor according to claim 8, wherein the first die-member operates in the direction perpendicular to the molding surface for molding the surface of the base plate, and the second die-member operates in a direction in which the portion extends.

10. A method of manufacturing a scroll member, including a base plate and a scroll wall, by a die having a first part including a molding surface for the scroll wall, a second part including a molding surface for the base plate, and a third part including a molding surface to form a protrusion of the scroll member, which extends in a direction substantially perpendicular to a direction in which the first and second parts separate from each other, the method comprising the steps of: casting the scroll member in the die; separating the first part from the second and third parts while the third part engages with the protrusion; disengaging the third part from the protrusion; and separating the scroll member from the second part.

11. The method of manufacturing the scroll member according to claim 11, further comprising the step of removing the protrusions.

12. A cast scroll member product made by the method of claim 11.