JPH0367776B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a rotor, specifically a method for manufacturing a rotor for a rotary compressor for air conditioning mounted on a car, a rotor for a rotary vacuum pump for brake control, etc. It is related to.

[Prior art]

In recent years, equipment mounted on automobiles has been required to be smaller and lighter in order to reduce fuel consumption and improve performance. Therefore, the parts used in these devices are also required to be lighter. The rotors of rotary compressors for air conditioning installed in automobiles and the rotors of rotary vacuum pumps for brake control are
Conventionally, iron-based sintered alloys were often used. In recent years, the use of aluminum has been considered for the purpose of weight reduction.

Conventionally, a rotor 51 of an air conditioning rotary compressor mounted on a car has a groove 52 in which a vane is housed, and a groove 52 at the bottom of the groove 52 for the purpose of reducing the stress concentration coefficient, as shown in FIG. A cylindrical part 53 is formed for the purpose of forming a relief part for the tool during finishing machining to facilitate machining, and for the purpose of applying back pressure to the vane to improve sealing performance, and a shaft into which a steel shaft is press-fitted. It has a hole 54.

A tensile stress is applied to the cylindrical portion 53 at the bottom of the groove of the rotor 51 due to the press-fitting of the shaft, and when the compressor is operating, gas pressure is applied as a load to the vanes that have protruded from the rotor. For use, the cylindrical part 53 which is the bottom of the vane groove
is subjected to repeated tensile stress as shown by the arrow. In addition, compressors for such applications usually compress refrigerant in a gaseous state, but in some cases they are operated with the refrigerant in a liquefied state, in which case very large impact stress is applied through the vanes. It acts on the cylindrical portion 53 at the bottom of the rotor groove. In addition, in order to downsize the compressor, it is necessary to bring the groove bottom cylindrical portion 53 of the vane as close as possible to the rotor shaft hole 54, and by doing so, the stress applied to the groove bottom cylindrical portion 53 is further reduced. It will be expensive.

Therefore, the aluminum alloy for the rotor needs to be a material with high strength and high toughness. However, the rotor 51 slides on the vanes going in and out of the groove 52, and further slides on the side plates at both end surfaces. Therefore, it is necessary to use a material with high wear resistance and seizure resistance.

Considering wear resistance and seizure resistance, a high-silicon aluminum alloy containing 10% or more of Si is appropriate. However, although it is easy to form the shape of the raw material using the casting method, it is difficult to form the shape of the rotor. It cannot withstand repeated stress applied to the bottom of the groove or impact stress during liquid compression. In order for such a material to withstand the above-mentioned load stress, it is essential to use a heat-treated material that has no casting defects and whose casting structure has been destroyed by forging.

Therefore, a hot extrusion method has conventionally been adopted as a method for manufacturing such a rotor.

In the conventional hot extrusion method, a rotor manufacturing process as shown in FIG. 6 was used.

First, as shown in FIG. 6a, an aluminum alloy billet 56 heated to 350°C to 450°C is inserted into a container 55 heated to 300°C to 400°C, and is diced by a stem 57. Pressure is applied in the direction of 58.

The die 58 is provided with a die hole 59 corresponding to the outer contour of the rotor 51 material, and by passing the billet 56 through the die hole 59, the extruded material 60 is given the outer contour shape of the rotor material. It will be done.

As shown in FIG. 6b, the stem 57 reaches a predetermined stroke to complete extrusion.

Thereafter, as shown in FIG. 6c, the container 55
Then, while the stem 57 is retreating in a direction away from the die 58, the remainder of the billet 56 is taken out from the container 55.

Next, as shown in FIG. 6d, the billet 56
The remaining portion is cut with a circular saw 61 in a portion close to the die 58.

Finally, as shown in FIG. 6e, the tip of the extruded material 60 is pulled to remove it from the die 58.

According to such an extrusion method, there is an advantage that a long extruded material can be obtained.

However, it has the following problems.

The extruded material is easily twisted, bent and warped, resulting in poor dimensional accuracy and low yield during finishing.

The stress on the die is high and the life is short. Particularly, the groove portion where the vane is housed is prone to breakage.

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 processing, the processing axis will become eccentric, making it impossible to ensure positional accuracy with respect to the groove that accommodates the vane. In addition, nicks and cracks that occur at the bottom of the groove act as notches when stress is applied during use, reducing durability.

During extrusion, a large pressing force of 800 to 2,500 tons is required, making the equipment large and expensive.

Because there are many sliding parts between the die and the extruded material,
Unless the speed is very low, cracks will occur in the extrusion. For this reason, although it is an expensive facility, productivity is extremely low, and the cost of the rotor material obtained is extremely high.

[Problem to be solved by the invention]

The present invention improves the disadvantages of dimensional accuracy, surface scratches, processing yield, and die life caused by the conventional hot extrusion method as described above, and reduces the repetitive stress applied to the bottom of the groove of the vane storage part and the problem during liquid compression. It is an object of the present invention to provide a method for manufacturing at a low cost an aluminum alloy rotor material in which the structure at least near the groove bottom of the vane storage portion is strengthened by plastic flow through forging in order to withstand impact stress. It is said that

[Means to solve the problem]

The present invention solves the above problem in a method of manufacturing an aluminum alloy rotor having a plurality of vane housings, by reducing the axially perpendicular cross section of the die hole with respect to the axially perpendicular cross section inside the container. Using a mold structure having a die and a container that are identical and coaxially arranged with respect to each other, a blank is inserted into the container, and the blank is inserted into the hole of the die having the outer contour shape of the rotor blank. A method for manufacturing an aluminum alloy rotor, characterized in that the blank in the die hole, which is pushed in by a pressure punch and backed up by a die plate, is knocked out and taken out through a container by a knockout punch in the die plate. Settled.

[Effect]

According to the present invention, a blank is inserted into a container, pushed into a die hole backed up by a die plate by a pressure punch, the die hole is filled with the blank, and a knock-out punch in the die plate is pressed. The blank is knocked out and removed through the container by a screw. At that time, pressure is applied from inside the container into the coaxial die hole so that the cross section perpendicular to the axial direction of the die hole is reduced or the same as the cross section perpendicular to the axial direction inside the container. As a result, we were able to plastically flow the structure of the rotor material near the grooves of the vane housing and strengthen it.

〔Example〕

The details of the present invention will be explained based on embodiments shown in the drawings.

As shown in Fig. 1, outer diameter D = 50.2 mm, circumferential diameter D1 = 14.33 mm where the cylindrical part 3 which is the groove bottom is arranged,
Inner diameter d of cylindrical portion 3 = 4.5 mm, width t of vane groove 2 =
An example of manufacturing a rotor material 1 for a rotary compressor for air conditioning mounted on a vehicle, in which the angular interval θ in the circumferential direction of the open end of the vane groove 2 is 72°, will be described.

In FIGS. 2 and 3, the die 5 includes a die inner circumferential portion 6 corresponding to the outer circumferential portion of the rotor material 1, a fin portion 7 corresponding to the vane storage groove 2,
A small cylindrical portion 8 corresponding to the vane groove bottom portion 3 is formed. The die 5 is made to have the same hole size as the rotor material 1 shown in FIG. 1, as shown in FIGS. 2 and 3.

FIG. 4 shows the structure of a mold for manufacturing rotor material by hot forging method, in which 9 is a container, 5 is the aforementioned die, and each is heated to 300°C to 300°C by a heater (not shown). Heated and maintained at 400℃. The axially perpendicular cross section of the die hole is reduced or substantially the same as the axially perpendicular cross section in the container, but the axially perpendicular cross section of the die hole in the container 9 is The ratio of cross sections perpendicular to the axial direction is preferably 1:1 to 1:2. When the ratio is less than 1:1, the rotor material that has been forged is often knocked out through a container. If it is 1:2 or more, a large pressing force is required, and the stress applied to the die becomes large.
The life of the die is shortened and the lubrication is likely to run out.

The dice 5 are arranged at least coaxially with the container 9, as shown in FIG.

As an example, the inner diameter of the container 9 is 50.3 mm, and the ratio of the cross-sectional area perpendicular to the axial direction of the hole of the die 5 to the cross-sectional area perpendicular to the axial direction of the container 9 is 1:1.1.
And so.

An example of an aluminum alloy is 11, which is manufactured by a hot-top continuous casting method.
Weight% (all percentages below indicate weight%) Si, 5%
A material consisting of Cu, 0.6% Mg, 0.3% Fe, 0.8% Mn, and the remainder substantially Al was used as a forged material, ie, a blank, with a diameter of 50 mm and a height of 45 mm. As an example, this blank is heated to 430℃, the container temperature is 430℃,
Hot forging was carried out as shown in Figure 4 at a die temperature of 400°C, and the maximum pressure during forging was 15 tons.

Reference numeral 10 denotes a die plate, which has a structure in which it completely contacts the fin portion 7 of the die 5 and the small cylindrical portion 8 at its tip.

A knock-out punch 11 is provided at the center of the die plate 10, and is adapted to knock out the rotor material 1 that has been completely forged upward in the figure. In addition, there is a pressure punch 12 at the top.
is attached to a platen (not shown).

The manufacturing process is carried out in the order shown in FIGS. 4a, b, and c.

In FIG. 4a, an aluminum alloy blank 13 heated to 350°C to 450°C in an external continuous preheating furnace (not shown) is automatically inserted into a container 9 and then forged by a pressure punch 12. This shows the state in which it has started. Note that, before forging, the container 9 and the die 5 are sprayed with an appropriate amount of a lubricant containing graphite as a main component to provide a thin lubricant film on their surfaces. The aluminum alloy blank 13 may not be lubricated, but it is preferable to provide the same lubricating film because it will be less likely to seize.

FIG. 4b shows a state in which the pressure punch 12 has completed a predetermined stroke movement. In this state, the aluminum alloy blank 13 is almost sealed inside the die 5, and is finished to a predetermined size. Further, during forging, measures must be taken in consideration of dimensional variations in the aluminum alloy blank 13. When using a hydraulic press, it is desirable to set the maximum load to prevent the die 5 from breaking. Further, in the case of a mechanical press, it is desirable to keep the stroke constant using the abutment method shown in the figure.

In FIG. 4c, after the blank 13 is formed into a predetermined shape by applying pressure with the pressure punch 12, the pressure punch 1
2 is moved by a predetermined stroke and separated from the container 9, and then the forged blank 13, that is, the rotor material 1, is taken out from the container 9 by the knockout punch 11.

In the hot extrusion method described above, since the extruded material must be passed through, it is not possible to back up the fin portion and the small cylindrical portion at the tip thereof using such a die plate. Therefore, large bending stress and shearing stress are applied to the portion where the fin portion connects to the inner peripheral portion of the die during extrusion, and the life of the die becomes extremely short. However, in the present invention, since there is backup by the die plate 10,
Bending stress and shearing stress on the fins can be significantly reduced and the life of the die can be extended.

Additionally, when forging is complete, the blank is almost sealed inside the die, resulting in a rotor material with high dimensional accuracy without bending, twisting, or warping.

In addition, since the lubrication effect can be exerted, it is possible to prevent scratches and cracks from occurring due to sliding of the blank with the container or die.

Using this method, 1000 rotors were cast and completed rotors were machined, and no processing defects occurred.

For comparison, 500 pieces were extruded into the same cross-sectional shape using a conventional hot extrusion method using an extruder with a container inner diameter of 210 mm at a maximum pressure of 2000 tons, and 500 pieces were completed.
The processing defect rate was 20%. In addition, scratches at the bottom of the vane groove occurred continuously except at the tip at the initial stage of extrusion, which has a die lubrication effect.

In the above example, a continuously cast aluminum alloy blank was used, but aluminum alloy powder containing high silicon (17%Si-4%Cu-1
It was confirmed that the rotor material could be manufactured using a blank made by hot compression molding of %Mg-5%Fe-balance Al).

In either case, in the structure near the lower part of the vane groove of the obtained rotor material, a part where plastic flow occurred due to forging was observed, and the strength and toughness were improved.

In the embodiment of the present invention, the pressure punch is provided in the upper part and the die is arranged in the lower part, but the structure may be turned upside down or may have a horizontal structure.

〔effect〕

In terms of manufacturing equipment, the present invention has the advantage that it does not require large-scale equipment used in conventional hot extrusion methods and can be made with small-sized equipment. In addition, the lubrication effect prevents scratches and cracks, so it has the advantage of being able to be manufactured at high speed.

According to the method of the present invention, it is clear that the rotor material can be manufactured using smaller equipment and has excellent dimensional accuracy and surface condition compared to manufacturing using the conventional hot extrusion method. Furthermore, in the hot extrusion method described above, since the extruded material must be passed through, it is not possible to back up the fin portion of the die and the small cylindrical portion at its tip using the die plate, which is possible with the present invention. Therefore, large bending stress and shearing stress are applied to the part where the fin part connects to the inner peripheral part of the die during extrusion, and the life of the die is extremely short. The bending stress of the die can be significantly reduced and the life of the die can be extended.

According to the rotor manufacturing method of the present invention, the structure of the rotor material near the groove of the vane storage part can be strengthened by causing plastic flow, thereby preventing twisting and bending.
To provide a rotor material that does not warp, have a long die life, and is free from galling and cracking, and can be manufactured at low cost using small equipment.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of a rotor for an air conditioning rotary compressor installed in an automobile manufactured according to the present invention, Fig. 2 is a plan view of a die, Fig. 3 is a side view of the die, and Figs. Fig. 5 is a perspective view of an example of a rotor of a conventional air conditioning rotary compressor mounted on a car, and Fig. 6 a to e are diagrams showing the steps of the manufacturing method according to the present invention. It is sectional drawing which sequentially explains the manufacturing process of a method. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Vane groove, 3... Groove end, 5... Die, 9... Container, 10... Die plate, 11... Knockout punch, 12
...Pressure punch, 13...Blank.

Claims (1)

[Claims] 1. In a method for manufacturing an aluminum alloy rotor having multiple vane housings, the axially perpendicular cross section of the die hole is reduced or substantially the same as the axially perpendicular cross section in the container, and the die holes are coaxial with each other. Using a mold structure with a die and a container disposed above, inserting an aluminum alloy blank into the container and pressing the blank into the hole of the die having the outer contour shape of the rotor material. The blank is pushed into the die hole by a punch and backed up by a die plate, and the blank is filled in the die hole, and the blank in the die hole is knocked out through a container by a knockout punch in the die plate and taken out. Method of manufacturing aluminum alloy rotor.