JPH02238191A - Rotor for vane rotary type compressor - Google Patents

Abstract

PURPOSE:To increase the fixture strength of a rotor to a shaft by providing a smaller diameter part in the middle of the circumferential surface of the shaft where the rotor of aluminum alloy is installed, forming knurling tool grooves in the smaller diameter part, and integrating the shaft with the rotor by melt forging. CONSTITUTION:A cover 5 and a cylinder block 6 are disposed between a front and a rear side block 3, 4, and a shaft 8 consisting of iron-based material is supported freely rotatably at the center of both side blocks 3, 4 through bearings 7. A smaller diameter part 8a is formed almost in the middle of this shaft 8, and knurling tool grooves 9 are formed in the circumferential surface of this smaller diameter part 8a. A rotor 10 consisting of Al-Si aluminum alloy is then installed in the circumferential surface of the shaft around the smaller diameter part 8a. In this case, the rotor 10 is molded by melt forging of Al-Si aluminum alloy, and the shaft 8 is integrated by casting simultaneously, thereby both bodies 8, 10 are strongly fixed to each other.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a rotor for a vane rotary compressor that can be easily and inexpensively produced. The rotor and the shaft are either fixed by press-fitting into the -M, or recently, weight reduction of compressors has been pointed out as a measure to improve the fuel efficiency of vehicles, and for this reason, the rotor is constructed of a lightweight aluminum alloy. A steel shaft is press-fitted into the shaft.

However, in this case, the coefficient of thermal expansion of the aluminum alloy that is the rotor member is larger than that of the steel that is the shaft member, so when the compressor is driven, slipping occurs at the press-fit parts, making it impossible to reliably transmit torque. There is a problem of damage.

Therefore, in order to solve the above problem, methods such as increasing the press-fitting allowance or lengthening the press-fitting length may be considered, but in this case, galling may occur during press-fitting, or the rotor may break at the press-fitting part. I can't hire someone because of resentment.

Also, for example, as in Japanese Patent Application Laid-open No. 59-68586,
When press-fitting a shaft with knurled grooves into an aluminum alloy rotor, the side surfaces of the rotor are pressurized in the axial direction to form a depression, and rotor material corresponding to the volume of the depression is bitten into the knurled groove. In addition, in the method of fixing both, knurled grooves are formed in the circumferential direction of the shaft, so the slip limit value against shaft torque is low, and there is not only concern that the shaft may slip, but also that the compression device There is a problem with increasing the size.

In view of these points, the applicant has developed various methods for strongly fixing the rotor and shaft, and has already filed applications for these methods. For example, in Japanese Utility Model Application No. 63-57380, a knurled groove is formed on the circumferential surface of the shaft, and an annular groove is provided on the circumferential surface of the shaft hole of the rotor that compresses the shaft to collect press-fit burrs, which occur during compression. The pressure plate is collected in the annular groove to prevent large pressure cracks.
In this issue, the rotor is extruded with aluminum alloy powder,
The joint strength between the shaft and rotor is strengthened.

(Problem to be Solved by the Invention) In the method already applied for, for example, in the former case, the function and strength are sufficient, but the dimensional tolerances of the shaft hole and shaft are strict. This results in high costs, and in the latter case, there are some problems in terms of yield.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a rotor for a vane rotary compressor, which allows the rotor to be manufactured easily and inexpensively, and which can strengthen the fixing strength between the rotor and the shaft. The purpose is to

(Means for Solving the Problems) Therefore, the rotor for a vane rotary type compressor of the present invention is a rotor for a vane rotary type compressor in which a rotor made of aluminum alloy is attached to the shaft, and the rotor for a vane rotary type compressor has an aluminum alloy rotor attached to the shaft. By providing a small diameter part in the part and forming a knurled groove in the small diameter part, it is possible to prevent the rotor from slipping around the shaft and to prevent the rotor from moving in the axial direction due to thermal expansion. By integrating the rotor and the rotor, it is possible to provide a rotor that is dense, has excellent mechanical properties, and has excellent seizure resistance and wear resistance.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.
In Figures 1 to 8, 1 and 2 are a front casing and a rear casing that form the outer shell of the compressor.
A front side block 3 and a rear side block 4 are arranged spaced apart between them, and a cover 5 and a cylinder block 6 are arranged between them. Above front side block 3 and rear side block 4
A bearing 7.7 is mounted at the center of the shaft 8, and a shaft 8 made of a ferrous material such as carbon steel or chrome steel is rotatably supported between these bearings 7.7.

A small diameter portion 8a is provided approximately in the middle of the shaft 8;
A knurled groove 9 is formed on the circumferential surface of a. The row red grooves 9 may be either so-called flat grooves, which are formed parallel to the circumferential surface of the shaft, or so-called cross-grain grooves, which are formed on the circumferential surface of the shaft in a lattice pattern. With this in mind, the flattening process described above was adopted. Then, on the shaft peripheral surface centered on the small diameter portion 8a. AI-
A rotor 10 made of Si-based aluminum alloy is attached. The rotor 1o has a substantially cylindrical shape as shown in FIG. 3, and a plurality of vane slots 11 for slidably accommodating vanes (not shown) are arranged radially inside the rotor 1o. It opens on the circumferential surface and side end surface of the metal.

At the inner end of the vane slot 11, the slot l1
A slightly wider vane slot inner 11a is formed, and the inner 11a is a high-pressure refrigerant gas passage (not shown).
In the figure, 12 is a concave oil reservoir formed on the side end surface of the rotor 10, and 13 is a concave oil reservoir formed on the peripheral surface of the rotor 1o. This is a bomb chamber defined by the inner peripheral surface of the cylinder block 6.

The rotor 10 is the eutectic point of AI-Si, 7%
It is composed of a hypereutectic Al-Si alloy containing silicon (Si) as described above, which has low thermal expansion, high high-temperature strength, light weight, and excellent wear resistance. Coefficient 8800Kg/mm2, tensile strength 41Kg/mm2,
An alloy with a hardness of H*B87 is used, and the alloy is processed using a molten metal forging process.
The rotor 10 is molded using the same method, and the shaft 10 is simultaneously cast into the body. The rotor 10 is formed by a known direct molten metal forging method or indirect molten metal forging method, an example of which is shown in FIGS. 5 to 8. 1 shows an example of the molding process and the mold used by the direct intrusion molten metal forging method. In the figure, 14 is a male punch that can move up and down, and is composed of a cylindrical body with approximately the same diameter as the outer diameter of the rotor 10. A plurality of vane slot molded pieces l5 and oil reservoir molded pieces 16 are provided protruding from the lower end surface.

The suppressing surface shapes of these molded pieces 15 and 16 are formed to be approximately the same as the hollow cross-sectional shapes of the corresponding vane slot 11 and vane slot inner 11a, and the hollow cross-sectional shape of the oil sump l2, as shown in FIG. The length is approximately the same as the axial length of the vane slot 11, that is, the length of the rotor 10, and the depth of the oil sump l2. Further, a recessed hole l7 into which the end of the shaft 8 can be inserted is opened in the center of the lower end surface of the punch l4, and a large diameter part 18 is further formed in the middle and high part of the bunch l4.

On the other hand, a bottomed cylindrical mold 19 is provided below the punch 14, and a molding chamber 2l capable of accommodating the molten metal 20 of the aluminum alloy is provided inside the mold 19. The inner diameter of the molding chamber 21 is approximately the same diameter as the outer diameter of the rotor lO, and is formed to be able to fit tightly with the punch l4, and an oil sump molding piece 22 similar to the oil sump molding piece l6 is provided on the bottom surface of the molding chamber 21. As shown in FIG. 7, they are protruded, and a through hole 23 into which the shaft 8 can be inserted is formed in the center thereof.

In the figure, reference numeral 24 denotes an engagement opening formed at the upper part of the opening of the molding chamber 21, which is formed to be able to fit tightly into the large diameter portion l8.

Figure 8 shows an example of the molding process and the mold used by the indirect intrusion molten metal forging method. A mold 26 and a lower mold 27 are provided.

A cylindrical punch guide 26a is protruded from the lower surface of the upper mold 26, and a guide hole 28 into which the punch 25 can be inserted is formed through the guide 26a. A plurality of molding chambers 29 are arranged on both sides of the punch guide 26a, and their lower ends are open to the lower surface of the upper mold 26. l5
A pen slot molded piece 30 and an oil sump molded piece (not shown) similar to the oil sump molded piece 16 are protruded, and a recessed hole 3l into which the upper end of the shaft 8 can be inserted is formed in the center thereof. ing.

On the other hand, the lower mold 27 has an upper surface 27a that can be tightly engaged with the lower surface of the upper mold 26, and a substantially mortar-shaped sump 32 that can accommodate the molten metal 20 is provided in the center of the upper surface 27a. There is. The lower end of the punch guide 26a is disposed in a protruding manner at the upper part of the sump 32 so that the punch guide 26a can be immersed into the molten metal 20, and the upper end of the sump 32 is opened at the lower end of the molding chamber 29. The runner to the chamber 29 is made as short as possible to enable slow and continuous movement of the melter 20. A shaft 8 is provided on the lower surface of the lower mold 27 facing the molding chamber 29.
An engagement hole 33 is provided that can maintain the upright state of the hole 3.
An oil sump molded piece (not shown) similar to the oil sump molded piece l6 is provided protruding around the opening of 3.

In the figure, 34 is a bottle insertion hole that communicates with the engagement hole 33,
A push-up bottle (not shown) can be inserted from below the lower mold 27.

In addition, reference numeral 35.35 in the figure indicates a relief stepped portion provided for grinding the end surface of the rotor 10.

(Function) When molding the rotor lO by such a molten metal forging method, it is necessary to machine the shaft 8 in advance. A small diameter portion 8a having a predetermined length, which in the embodiment is equal to or less than the length of the rotor 10, may be formed on the circumferential surface of the shaft on which the lO is attached, and a knurled groove 9 may be formed along the axial direction on the circumferential surface of the portion 8a.

In this case, since the shaft 8 is integrally cast with the rotor lO as described above, strict dimensional tolerances and processing accuracy are not required as in the conventional press-fitting method, and therefore, the processing of the shaft 8 is much easier. This makes it easy to reduce processing costs.

Using the thus machined shaft 8, for example,
The rotor 1 is actually produced by the direct intrusion molten metal forging method shown in the figure.
When molding 0, as a preparatory work, the bunch 14 and the mold 19 are cleaned, preheated to a predetermined temperature, and a graphite-based mold coating agent, for example, is applied to their peripheral surfaces.

On the other hand, before and after the above operation, the processed shaft 8 is carried into the molding chamber 2l of the mold 19, and at this time, one of the annular grooves 35 is aligned with the bottom surface position of the molding chamber 2l, and as shown in FIG. ), the upper half of the shaft 8 is held upright in the molding chamber 2l.

Under these circumstances, the molten metal 20 of hypereutectic Al-Si aluminum alloy heated to a predetermined casting temperature is poured into the molding chamber 2.
1, and immediately after pouring the molten metal, the punch 14 is lowered and pushed into the molding chamber 2L. In this way, the vane slot molded piece 15 protruding from the lower end of the punch 14 is immersed into the molten metal 20, and then the punch 14 is similarly immersed into the molten metal 20, pushing the molten metal 20 in the liquid phase region. At the same time, this molten metal 20 is pressurized and compressed before it becomes a semi-molten region of liquid phase and solid phase, and when the molten metal 20 in the molding chamber 2L is compressed by the length of the rotor 10, the descent of the punch l4 is stopped. do.

In the embodiment, the molten metal 20 is pressurized at 500 to 1500 kg/cm2, and this pressure compression action is performed until the molten metal 20 is completely solidified, and during this pressurization process, the vane slot molded piece 15 and the oil sump molded piece 16. 22, the pen slot 11, the inner 11a, and the oil reservoir 12 are molded.

Therefore, the molten metal 20 is forcibly pressed against the inner circumferential surface of the mold l9 and the surfaces of the vane slot molded piece l5 and the oil sump molded piece 16.22 due to the pressure, while inside the molten metal, this is pressed against the row red groove 9. and solidify.

Therefore, when the molten metal 20 solidifies, no air gap is generated between the molten metal 20 and their contact surfaces due to solidification contraction, and heat transfer is improved, shortening the solidification time and promoting rapid cooling. As a result, the solidified structure becomes finer, improving mechanical properties, and at the same time, the casting surface becomes extremely smooth, improving dimensional accuracy.

In this case, if rapid cooling is promoted as described above during the solidification process,
Due to insufficient diffusion, dendrites
) There is a concern that the structure will be more likely to segregate and the mechanical properties will deteriorate; however, as mentioned above, since the pressurized compression action is performed until the molten metal 20 is completely solidified, the occurrence of the above segregation is suppressed, Forms a nearly isotropic structure.

Therefore, in products processed in one direction such as rolled or forged products, the dendrites elongate in the forging direction and exhibit a so-called fibrous structure, resulting in directional mechanical properties, but in Doki molten metal forging, this There are no such problems.

Further, since the molten metal 20 is pressed against the knurled grooves 9 and solidified by the above-mentioned pressurization, the adhesion to the knurled grooves 9 is improved, and a tight bonding state between the two can be obtained. in this case,
Since the hypereutectic Al--Si alloy has very good fluidity of the molten metal, together with the above-mentioned pressurization, the molten metal 20 can easily wrap around the row red groove 9, and this effectively affects the above-mentioned bonding.

Moreover, the pressurization prevents the occurrence of casting defects such as shrinkage cavities, and the difference in quality between the inside and outside of the molten metal 20 is smaller than that of ordinary castings, which only promotes higher density and homogenization. In addition, the pressurization increases the gas solubility, thereby suppressing the occurrence of blowholes, bottle holes, etc. due to residual gas in the molten metal. 6 In this way, the rotor lO and shaft 8 are
When molding the rotor 10 in one piece, the desired molded product can be obtained by pouring a fixed amount of molten metal 20, so the yield is better than when extruding powdered aluminum alloy. Since the vane slot l1, the inner vane lla, and the oil reservoir l2 can be molded in parallel, this type of molding can be carried out rationally.

When the solidification of the molten metal 20 is completed in this way, the pressurized compression action is released, the punch l4 is moved upward, and
For example, the rotor lO, which is integrated with the shaft 8, is taken out from the molding chamber 2l via a push-up bottle (not shown).

On the other hand, when the rotor 10 is molded by the indirect molten metal forging method shown in FIG. 8, for example, as shown in FIG. are inserted and housed in an upright state, and then the upper mold 26 and the lower mold 27 are clamped. The positioning of the shaft 8 in this case is the same as described above.

Under these circumstances, the molten metal 20 of the hypereutectic Al-Si aluminum alloy heated to a predetermined casting temperature is poured into the sump 32.
Immediately after pouring the molten metal into the molten metal, the punch 25 is lowered to push the molten metal into the molten sump 32 through the guide hole 28. In this way, the liquid phase molten metal 20 accommodated in the sump 32 is pushed away by the punch 25 and continuously pushed into the molding chamber 29, 29 at a low speed as shown in FIG. 8(b). The inner circumferential surface of the chamber 29 and the upper surface 2 of the lower mold 27 facing the chamber 29 are subjected to pressurization and compression within the chamber 29.29.
7a and the vane slot molding piece 30 accommodated in the molding chamber 29, etc.

The above-mentioned pressure is the same as described above, and this pressurizing and compression action is performed until the molten metal 20 is completely solidified, as described above, thereby obtaining the same quality as described above.

When the molten metal 20 has completely solidified in this way, the pressure compression action is released, the punch 25 is moved upward, the upper mold 26 is also moved upward, and the shaft 8 is pushed up via a push-up bottle (not shown). , the rotor 10 integrated with the shaft 8 is placed in the molding chamber 2.
Take it out from 9.

As described above, the indirect molten metal forging method allows a plurality of rotors 10 to be molded in one molding process, and therefore can achieve mass production of molding compared to the above-mentioned direct molten metal forging method. The raw material 10 taken out from the molding chamber 21 or 29 is then removed from casting burrs or cut and its peripheral surface ground, completing a series of molding operations. In this case, when grinding the end surface of the rotor 10, since the row red groove 9 is completely cast into the rotor 10 and is not exposed on the end surface of the rotor 10, the grinding chips dig into the groove 9, which causes the compressor. There is no need to worry about it falling off after assembly and turning into foreign objects.

Since the rotor 10 manufactured in this manner is made of a hypereutectic Al-Si alloy as described above, its thermal expansion is small (for example, the coefficient of thermal expansion of 18 to 25% Si is 3.
18.3~22.3XIO-') between 0~300℃,
It has high strength at high temperatures, is lightweight, and has excellent wear resistance.

Therefore, the vane slot 1 formed in the rotor lO
Even if a vane (not shown) slides inside the slot l1 at high speed and the part becomes hot, the width of the slot l1 is kept substantially uniform;
Since the friction with the vanes is suppressed, the seizure of the vanes due to the heat generation is prevented, and the wear of the vanes and the vane slots 11 is reduced by improving the wear resistance and high temperature strength. Since these are integrally cast together and increase the contact area at the joint through the row red grooves 9, the slip limit value against shaft torque is high and the slip around the rotor 10 relative to the shaft 8 is reduced. Furthermore, since the rotor 10 and the shaft 8 are connected through the small diameter portion 8a, even if the rotor 10 thermally expands in the direction coaxial with the shaft 8 when the compressor is driven,
Since the coefficient of thermal expansion of the rotor 10 around the small diameter portion 8a is larger than that of the shaft 8, the small diameter portion 8a is always kept in a tightened state by the rotor IO, and the rotor 10 is engaged with the stepped portion of the small diameter portion 8a. This prevents movement in the axial direction.

(Effects of the Invention) As described above, the rotor for a vane rotary type compressor of the present invention has a rotor for a vane rotary type compressor in which a rotor made of aluminum alloy is attached to the shaft, and the rotor has a small diameter in the middle part of the circumferential surface of the shaft on which the rotor is attached. Since a knurled groove is formed in the small diameter part, a high sliding limit value around the rotor axis can be obtained with respect to the shaft torque, and it is possible to prevent the rotor from sliding around the axis, and also to prevent the rotor from sliding around the axis due to thermal expansion of the rotor. can prevent the movement of

In addition, since the shaft and rotor are integrated using the molten metal forging method in the present invention, it is possible to provide a rotor that is dense, has excellent mechanical properties, and has excellent seizure resistance and wear resistance. By being able to reduce the machining accuracy of the shaft,
This can be manufactured easily and inexpensively, and has the effect of improving yields compared to the conventional extrusion molding method of powdered aluminum alloy.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of a vane rotary compressor to which the present invention is applied, Fig. 2 is an enlarged sectional view taken along line A-A in Fig. 1, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a front view showing an example of a shaft applied to the present invention, FIG. Figure 6 shows the situation before pressing, and Figure (b) shows the situation after pressing. Figure 6 is a bottom view of the punch applied to the molten metal forging method described above, and Figure 7 shows the punch applied to the molten metal forging method described above. FIG. 8 is a plan view of the mold, and a cross-sectional view showing the molding process by the indirect molten metal forging method applicable to the present invention; FIG. 8(a) shows the state before pressurization, and FIG.
shows the situation after pressurization. 8...Shaft, 8a...Small diameter portion 9...Knurled groove, 10...Rotor diagram (Fig. 6 of b)

Claims (1)

[Claims] In a rotor for a vane rotary compressor that has an aluminum alloy rotor attached to the shaft, a small diameter section is provided in the middle of the circumferential surface of the shaft on which the rotor is attached, a knurled groove is formed in the small diameter section, and the shaft and rotor are connected. A rotor for a vane rotary compressor that is integrated using a molten metal forging method.