JPH0367775B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing a rotor, and more specifically, a method for manufacturing rotors for rotary compressors for air conditioning installed in automobiles, rotors for rotary vacuum pumps for brake control, etc. It is related to. [Conventional technology] Iron-based sintered alloys have traditionally been used for the rotors of air-conditioning rotary compressors installed in automobiles and the rotors of rotor-type vacuum pumps for brake control, but in recent years iron-based sintered alloys have been used for the purpose of weight reduction. The use of aluminum is being considered. As shown in FIG. 8, a groove 52 in which a vane is housed is cut into the rotor of an air-conditioned rotary type installed in an automobile. At this tip, the purpose is to reduce the concentration factor of stress applied to the groove 52 and its bottom, and the purpose is to form a relief part for a tool during finishing machining of the groove to facilitate machining.
A cylindrical portion 53 is often formed for the purpose of applying back pressure to the vane and improving sealing performance. The rotor 1 also has a shaft hole 54 into which a steel shaft is press-fitted. Tensile stress acts on the cylindrical portion 53 at the bottom of the groove due to the shaft being press-fitted into the shaft hole 54, and when the compressor is in operation, the vanes housed in the groove 52 are
In order to repeatedly slide within the groove while compressing the refrigerant, tensile stress is repeatedly applied to the cylindrical portion 53. As compressors become smaller, it becomes necessary to move the cylindrical portion 53 of the vane as close to the shaft hole 54 of the rotor as possible, and the stress applied to the cylindrical portion 53 from the steel shaft becomes even higher. In order to withstand such load stress, aluminum alloy must have no casting defects due to its material properties.
It is essential that the cast structure is destroyed in the grooves by forging, etc., and that it has heat treatability. The method for manufacturing such a rotor is as follows:
Conventionally, a hot extrusion method was used that completely destroyed the cast structure. This method has the advantage that a long extruded material can be obtained and a large number of rotors can be efficiently manufactured by cutting, but it has the following problems. The extruded material is easily twisted, bending and warping, resulting in poor dimensional accuracy and low retention during finishing. The stress on the die is high and the life of the die is short. The die is particularly prone to breakage at the groove portion where the vane is housed. Since almost no lubrication effect can be expected between the die and the extruded material, galling and cracking occur in the extruded material. If there is any galling or cracking on the outer periphery, which serves as a processing reference during finishing, the machining axis of the vane housing or shaft hole will become eccentric, making it impossible to ensure the positional accuracy of the groove that houses the vane. In addition, nicks and cracks that occur in the cylindrical portion of the groove bottom act as notches when stress is applied to the cylindrical portion during use, reducing the durability of the rotor. During extrusion, a large pressing force of 800 to 2,500 tons is required, making the equipment large and expensive. Unlike a round bar, the rotor is a deformed material, so there are many sliding parts between the die and the extruded material, which can cause cracks in the extruded material unless extruded at a very low speed. For this reason, although it is an expensive facility, productivity is extremely low, and the cost of the rotor material obtained is extremely high. Furthermore, as compressors become smaller, manufacturing the rotor becomes more difficult. That is, as the diameter of the rotor becomes smaller and the performance becomes higher, it becomes necessary to ensure the length of the vane as long as possible, so the cylindrical portion at the bottom of the groove in the vane storage portion approaches the shaft hole. In order to keep this distance above a certain level in order to ensure the strength of the rotor, it is also necessary to increase the shift amount f of the groove 52 from the center of the rotor axis, as shown in FIG. This leads to the wall thickness of the groove 52 and the outer peripheral surface of the rotor becoming thinner on one side of the groove, which further causes the aforementioned problem of susceptibility to twisting due to the imbalance of plastic flow during extrusion. This causes further deterioration of mold life and dimensional accuracy. The present applicant has previously proposed a method perpendicular to the axial direction in the container with respect to a cross section perpendicular to the axial direction of the die hole, as a means to improve the shortcomings of dimensional accuracy, surface scratches, processing yield, and die life due to the conventional hot extrusion method. A heated blank is placed in a heated container using a mold structure having a container with a cross-sectional area ratio of 1:1 to 1:2 and a die backed up by a container and a die plate arranged coaxially with each other. Insert
The blank is pushed into the hole of a heated die having the outer contour shape of the rotor material using a pressure punch, filling the space created by the die-container-punch-die plate, and the shaped blank is inserted into the die. A manufacturing method is provided in which the plate is knocked out and taken out through a container using a knockout punch in the plate. FIG. 10 shows an example of the entire mold structure exemplified in this patent application, and the die 5b consists of a die body that is shrink-fitted by a die ring, as shown in detail in FIGS. 2 and 3. , the outer contour of the rotor material (see Figure 8) becomes the die space 2
It has a dimensional shape, and one end surface of the die 5b is in close contact with the die plate 13. A container 12 is heated and maintained at 300 to 450°C by a heater (not shown) together with the dice 5b. Reference numeral 13 denotes a die plate, which has a structure that completely contacts the fin portion 10 (FIG. 2) of the die 5b and the small cylindrical portion 11 (FIG. 2) at the tip thereof.
3 (Fig. 10), a knockout punch 14 is provided in the center of the rotor material 15 after forging is completed.
is designed to be knocked out in the upward direction of the diagram. Further, a pressure punch 16 is attached to a platen (not shown) at the top. If this method is used, the fin portion 10 of the die corresponding to the vane storage portion
Although it is possible to significantly reduce the axial shear stress acting on the rotor (Fig. 2) and extend the life of the die, the shift amount f (Fig. 9) from the shaft center is ) increases, the plastic flow is caused by V on one side of the fin of the die hole.
It becomes larger in the character-shaped area a, and the area V on the opposite side
This causes an imbalance in the plastic flow, which causes a force to act on the fin section during molding in the direction of the arrow in Figure 2, causing folding deformation of the fin section 10 of the die, which impairs the dimensional accuracy of the rotor material. It was also found that there was a problem with the die life. [Problems to be Solved by the Invention] The present invention is an aluminum alloy that further improves dimensional accuracy by adding a mechanism to prevent folding deformation of the fin portion that corresponds to the vane housing portion, in a method for manufacturing a rotor that punches an aluminum alloy. Our objective is to provide a method for manufacturing rotor materials. [Means for Solving the Problems] The present invention solves the above problems by providing a blank made of an aluminum alloy for manufacturing a material for an aluminum alloy rotor in which vane storage grooves are cut inward from the circumferential surface. is inserted into a container and placed in a bottomed die having an inner circumferential surface that defines the outer circumferential shape of the rotor material and also serves as the base of the fin section described below, and a fin section that defines the shape of the vane storage groove. pressing the blank with a pressure punch to fill the die hole defined by the bottom, inner peripheral surface, and fin portion, and reducing the cross-sectional area of the blank with respect to the cross-sectional area of the container; and then actuating a knock-out punch whose tip surface functioned as part of the bottom of the die in a direction opposite to the pressing direction of the pressure punch to eject the blank out of the container. In the method for manufacturing a manufactured rotor material, an extended fin portion extending toward the bottom of the die hole is integrally provided in the fin portion, and a space is provided or placed between at least a part of the circumferential surface of the extended fin portion. Instead, a backup part having a groove into which the extended fin part is inserted is provided, and the sagging of the fin part is prevented by the extended fin part coming into contact with the groove during blank processing, thereby solving the problem. Specifically, as will be explained in the examples below, a space perpendicular to the axial direction of the die hole is used to prevent the mold fins forming the vane storage part and the small cylinder from collapsing, which is a particular problem in terms of mold strength. A mold having a back-up plate having a dimension of preferably 0.008L or less in whole or in part, where L is the distance between the die and the fin part in the cross section from the mold base to the center of the small cylindrical part. structure, or use a mold in which the backup plate and die are integrally molded. [Operation] The method of the present invention needs to satisfy the following requirements. An inner circumferential surface that determines the outer circumferential shape of the rotor material and also serves as the base of the fin portion described below;
This is a forging method in which a blank is pushed into a die with a pressure punch, which has a fin section that defines the shape of the vane storage groove, and the die hole defined by the bottom, inner peripheral surface, and fin section is filled with the blank. thing. By using such a die forging process, the shape of the outer circumferential surface of the rotor material and the vane housing groove can be formed all at once without using an extrusion method. In order to take the blank out of the die after molding, the knockout punch is operated in a direction opposite to the pressing direction of the pressure punch to take out the blank out of the container. The tip of this knockout punch functions as part of the die bottom during forging. The cross-sectional area of the container is increased or remains substantially the same relative to the area perpendicular to the axis of the die bore. If the cross-sectional area of the die hole is larger than the container, it will be difficult to take out the blank with a knock-out punch, so the cross-sectional area of the die hole must be avoided to be larger than the cross-sectional area of the container. With such a processing method, the structure of the rotor material in the vicinity of the groove of the vane storage portion can be made to plastically flow, thereby making it possible to strengthen the rotor material. The deformation of the fins, such as the fins caused by the imbalance of plastic flow mentioned above, is backed up by the bottom of the die, and the main part of the fin (other than the extension part) is to prevent undesired collapse or twisting of the When a die is machined into a two-dimensional shape using a wire electrical discharge machine or the like and used, a back-up to prevent deformation of the fin part is fitted on the circumferential surface of the die or the end part of the fin part (the bottom part of the die), or a gap is installed. By not forming a punch and using a bottomed mold having a hole through which a knockout punch passes, the back-up effect can be delayed. When using the inset type, there is a gap on the fin circumference.
It becomes necessary to form , and during that time the amount is
It is preferable that the total or partial size is 0.008 L or less when measured in a direction perpendicular to the circumferential surface of the fin portion. However, as shown in FIG. 1, L is the distance from the base of the fin section 10 to its tip (if there is a cylindrical section 11, the distance to its tip).
When the distance 74 is 0.008L or more, the amount of folding deformation of the fin portion 10 is large, and the wall surface at the bottom of the die is originally in contact with the end of the fin, and even in a situation where it should be backed up, the end portion is not backed up and becomes plastic. This is not preferable because it will cause deformation. In this case, the fins may undergo plastic deformation, and the twisting of the vane housing groove may exceed the machining and finishing allowance for the rotor material. Once plastic deformation occurs, it does not return to its original position, which is extremely inconvenient in mass production, as there is a risk that many defective products will be produced. As a back-up for preventing deformation of the fin portion of a die processed into a two-dimensional shape, a back-up plate fitted into the bottom of the die is used so as to form the bottom of the die. That is, in this case, parts constituting a part of the die other than the die 5b and the die plate 13 (see FIG. 10) are used as the backup plate. The back-up plate is shown in FIG. 4, for example, and has a hole 71 in the center through which a knock-out punch passes, and a groove 72 into which the fin portion and cylindrical portion of the die enter, respectively, and a cylindrical portion 73. It is rare. Main surface 4 of backup plate 4
a constitutes a part of the bottom surface of the mold. FIG. 1 is a horizontal sectional view of the bottom of the die, showing the relationship between the die 5b' and the backup plate 4.
The die 5b' has a small gap 7 so that the fin part 10 can be easily inserted into the groove 72 of the back-up plate 4 and the cylindrical part 73 (FIG. 4).
4, and the ring-shaped part that becomes the base from which the fin part 10 protrudes also has a small gap 74 between it and the back-up plate 4 on the side surface, and the die hole is formed on the main surface of the back-up plate 4. 4
a and the tip of the knockout punch. Regarding the method of setting the backup plate in the die space, in addition to the method of fitting it in, it is also possible to fix it to the die plate 13 with bolts 32 as shown in FIG. 5a. Although not shown, it is also possible to fix the backup plate 4 to the die 5b. Furthermore, it is also possible to integrate the die plate 13 and the backup plate 4 as shown in FIG. 5b. Furthermore, Figure 5c
As shown in FIG. 5d, which is a cross-sectional view taken along the line A--A, the die may be integrated with a die and have a bottomed mold having a hole through which a knockout punch passes. In addition, in the case of using a die with a bottom, it is advantageous for the life of the mold to provide the joint portion between the fin portion and the bottom surface of the die with as large a corner radius as possible. Dice 5b (6th
The cross-sectional area perpendicular to the axial direction of the die hole (see figure) S ₁
is preferably 1:1 to 1:2 with respect to the cross-sectional area _S2 perpendicular to the axial direction inside the container 12. If this ratio is less than 1:1, the rotor material that has been forged cannot be knocked out through the container 12. On the other hand, if this cross-sectional area is 1:2 or more, a large pressure is required to force the rotor material into the die hole, which increases the load stress on the die 5b, shortens the life of the die 5b, and causes loss of lubrication. Cheap. A heated blank using the above mold structure is inserted into a heated container, and is pushed into a heated die or mold by a pressure punch, so that the blank is inserted into the molding space within the die or mold. When the container is almost full, the blank is knocked out through the container by the knockout punch 14 and taken out. By this method, a back-up effect was obtained against the folding deformation of the mold fins caused by imbalance of plastic flow in the blank during forging, and a rotor material with good accuracy could be obtained. Furthermore, we were able to strengthen the structure of the rotor material near the grooves of the vane storage section by causing plastic flow. [Example] The details of the present invention will be explained based on the example shown in the drawings. As shown in FIG. 9, the outer diameter D = 50.2 mm, and the circumferential diameter D ₁ = where the plurality of cylindrical parts 53 are arranged at the bottom of the groove.
14.33mm, inner diameter d of cylindrical part 53 = 4.5mm, (vane)
Width of the groove 52 t = 2.7 mm, angular interval θ in the circumferential direction of the open end of the (vane) groove 52 = 72, shift amount from the rotor axis center to the (vane) groove center f = 10 mm
Rotor material 1 for a rotary compressor for vehicle-mounted air conditioning was manufactured. The die 5b shown in FIGS. 2 and 3 has a fin portion 10 corresponding to the groove 52 and a small cylindrical portion 11 corresponding to the groove bottom from the die inner circumferential portion 6 corresponding to the outer circumferential portion of the rotor material 1. Five stand out. The die 5b is manufactured to have a hole size that takes into consideration thermal expansion with the mold material during hot forging so that the above-mentioned dimensions can be obtained as the rotor material dimensions after molding. In addition, the distance L from the base of the die fin part to the center of the small cylinder part
(See Figure 1) is approximately 12.5 mm. In FIG. 7, 12 is a container, and 5b
4 is a die, and 4 is a backup plate, each of which is heated to 300℃ by a heater (not shown).
Heated and maintained at ~400℃. Reference numeral 13 denotes a die plate, which is structured to be in close contact with the fin portion 7 and small cylindrical portion 8 of the die 5b. The backup plate 4 had a shape as shown in FIG. 4, and had a thickness tb of 8 mm. The distance from the die 74 (see Figure 1) is 0.02mm (12.5mmx0.008=
0.10mm or less). An example of an actual forging operation will be explained below. The inner diameter of the container 12 (see Figure 7) is 50.3
mm, and the ratio of the cross-sectional area perpendicular to the axial direction of the die hole of the die 5b to the cross-sectional area perpendicular to the axial direction of the container 9 was set to 1:1. A knock-out punch 14 is provided on the die plate 13 and the die 5b, so that the rotor material 1 that has been completely forged is knocked out upward in the figure. As an aluminum alloy, 11% by weight manufactured by hot-top continuous casting method.
(All percentages below indicate weight%) Si, 5% Cu, 0.6%
A material consisting of Mg, 0.3% Fe, 0.8% Mn, and the remainder substantially Al was made into a forged material, ie, a blank, with a diameter of 50 mm and a height of 45 mm. This blank is heated in a continuous heating furnace.
It was heated to 350 to 450°C and hot forged in the process shown in Fig. 7 under the conditions of a container temperature of 480°C and a die temperature of 400°C. The maximum pressure during forging was 15 tons. FIG. 7a shows a state in which the heated blank 15 is automatically inserted into the container 12 and then forging is started by the pressure punch 16. Note that the container 12 and the die body 5b are
Before forging, an appropriate amount of lubricant mainly composed of graphite was sprayed to form a thin lubricant film on the surface. The surface of the blank 15 may not be lubricated, but it is more difficult to seize if the same lubricant film is provided on the die body 5b. FIG. 7b shows a state in which the pressure punch 16 has completed a predetermined stroke movement and the blank 15 has been forged into the die 5b. In this state, the blank 15 is in a sealed state inside the die 5b,
Finished to specified dimensions. Further, when mass-producing forging, it is necessary to take measures that take into consideration dimensional variations in the blank 15. For example, when using a hydraulic press, set the maximum load, and when using a mechanical press, keep the stroke constant using the butting method shown in the figure to minimize the risk of die breakage. desirable. In FIG. 7c, the blank 1 is punched by the pressure punch 16.
After forming the rotor material 5 into a predetermined shape, the pressure punch 16 is moved back by a predetermined stroke to remove the container 12.
Then, the forged blank 15, that is, the rotor material, is taken out from the container 12 using the knockout punch 14. As explained above, at the end of forging, the die is almost completely filled with blanks, so it is possible to manufacture a rotor material with high dimensional accuracy without bending, twisting, or warping. Furthermore, the above method
Compared to the hot extrusion method, it is possible to apply lubricant to the die etc. after each forging process to achieve a lubricating effect, which reduces the occurrence of scratches and cracks caused by sliding between the container and die and the blank. I can do it. In order to quantitatively demonstrate the effect of the back-up plate, which is a feature of the present invention, the common condition is that the die fin part has a die plate as a part that backs up in the forging axis direction, and dies of the same size are used. We investigated by actual forging how the presence or absence of a back-up plate affects the amount of folding deformation of the die fin. The measurement results are shown in the table below.

〔Effect of the invention〕

According to the method of the present invention, a better lubrication effect can be obtained compared to the hot extrusion method, and scratches and cracks are less likely to occur, and the back-up plate for preventing the die fin from collapsing provides a high-precision rotor Can be manufactured at high speed using small equipment with low capacity materials. In addition, according to the method of the present invention, the surface condition and dimensional accuracy are superior compared to rotor materials obtained by manufacturing using conventional hot extrusion methods, so the finishing allowance can be set to a small amount, reducing the burden of post-processing. can. In addition, due to the back-up effect of the die fin, which poses a strength problem, when the fin receives bending stress and shear stress in the rotor shaft axis direction, and further receives bending stress acting in the folding direction, the die fin Deformation can be significantly reduced,
Dice life can be extended. If the method of the present invention is applied to the method previously provided by the applicant, dimensional accuracy, surface scratches, processing yield, die life, etc. can be improved, and the repetitive stress applied to the groove bottom of the vane storage part and the impact during liquid compression can be improved. In order to withstand such stress, at least the structure near the vane storage area and the groove bottom is strengthened by plastic flow through forging, and a mechanism is also added to prevent the mold fins that correspond to the vane storage area from collapsing. By doing so, dimensional accuracy can be further improved. Furthermore, it was possible to strengthen the structure of the rotor material near the groove of the vane housing by causing the composition to flow.

[Brief explanation of drawings]

Figure 1 is a horizontal sectional view of the die bottom and backup plate used in the method of the present invention;
The figure is a plan view of a die without a backup plate previously provided by the applicant;
Figure 4 is a perspective view of the backup plate, Figures 5a and b are explanatory diagrams of how the backup plate is assembled into the die, and Figures 5c and d are the die and backup plate integrated. , a plan view and a cross-sectional view of the mold with a bottom, FIG. 6 is an explanatory diagram of the cross-sectional area of the die and the container, and FIG. 7 a-
c is a cross-sectional view of a forging device showing the steps of the manufacturing method according to the present invention, FIG. 8 is a perspective view showing an example of a rotor for an air conditioning rotary compressor mounted on a car, and FIG. 9 shows the dimensions of the rotor. The plan view, FIG. 10, is an explanatory diagram of the method previously proposed by the applicant. 1... Rotor, 2... Vane groove, 4... Backup plate, 5b... Die, 12... Container, 13... Die plate, 13... Blank, 14... Knockout punch, 16... Machining Pressure punch, 52... Vane storage groove, 53... Cylindrical portion, 54... Shaft hole portion, 74... Interval.

Claims (1)

[Scope of Claims] 1. A blank made of an aluminum alloy for manufacturing an aluminum alloy rotor material in which vane storage grooves are cut inward from the circumferential surface is inserted into a container, and a blank made of the aluminum alloy is inserted into a container. The blank is pushed with a pressure punch into a die with a bottom, which has an inner peripheral surface that defines the outer peripheral surface shape of the material and also serves as the base of the fin section described below, and a fin section that defines the shape of the vane storage groove. filling the die hole defined by the bottom, inner circumference and fins with the blank while reducing or keeping the cross-sectional area of the blank substantially the same with respect to the cross-sectional area of the container; ,
In the method for manufacturing an aluminum alloy rotor material, the blank is taken out of the container by operating a knock-out punch whose tip surface functions as a part of the die bottom in a direction opposite to the pressing direction of the pressure punch. The extension fin portion is integrally provided with an extension fin portion extending toward the bottom of the die hole portion, and the extension fin portion is arranged with or without a gap between at least a part of the circumferential surface of the extension fin portion. A method for manufacturing an aluminum alloy rotor material, characterized in that a back-up portion having a groove into which the blank is inserted is provided, and sagging of the fin portion is prevented by contact between the extended fin portion and the groove during processing of the blank. 2. The method for manufacturing an aluminum alloy rotor material according to claim 1, wherein the bottom portion of the die is constituted by a backup plate integrally fixed with the die or fitted into the die, and the backup plate is used as the backup portion. . 3. The method of manufacturing an aluminum alloy rotor material according to claim 1, wherein the tip of the die plate holding the die protrudes into the die, and the extension fin is inserted into the bottom of the die. 4. The method of manufacturing an aluminum alloy rotor material according to claim 1, wherein a mold is used in which the inner circumferential surface, the fin portion, and the bottom portion are integrally molded.