JP2910123B2 - Method of forming oil sump groove on the end face of aluminum alloy rotor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an aluminum rotor of a vane rotary type compressor, and more particularly to a method of forming a seizure preventing oil reservoir groove of a lightweight aluminum alloy rotor. It is.

[Conventional technology]

A rotor of a compressor used for a car air conditioner or the like has a plurality of vane grooves in which vanes slide as shown in FIG. 1 and is integrated with a rotating shaft.
The rotor rotates while sliding on inner wall surfaces of side plates fixed to both sides of the cylinder block. 5 of rotor, vane, cylinder block, both side plates
The cooling gas sucked into the compression chamber divided by two parts
After compression, it is discharged. Since the compression chamber requires airtightness, the clearance between the components is designed to be extremely small. In addition, since the rotor and the side plate slide while receiving a compressive force, seizure easily occurs.

Conventionally, a rotor is made of steel or an iron-based sintered alloy, and a side plate is made of flaky graphite cast iron or an iron-based sintered alloy. In the combination of iron-based materials, the wear resistance of the material is relatively good, and flaky graphite cast iron and sintered alloy are excellent in oil retention, so the problem of seizure was not so serious, but in some cases, An oil sump groove was provided on one end or both sides of the rotor to prevent seizure.

In recent years, the need for lighter compressors has increased, and aluminum-based iron-based materials have been studied. With the development of powdered aluminum alloys made from rapidly solidified powders and high-strength aluminum materials with advances in continuous casting technology, it has become possible to convert rotors to aluminum, which could not be used with conventional aluminum materials. As for the side plate, aluminum can be used by adopting Al-high Si material such as A390 material. Although these alloys contain a large amount of alloy components such as Si to improve wear resistance and seizure resistance and maintain a high level of clearance accuracy, the seizure resistance between the rotor and the side plate is high. It is not sufficient, and especially when oil runs out on the sliding surface, seizure easily occurs. Therefore, an oil sump groove on the rotor end face is essential.

[Problems to be solved by the invention]

However, in the case of aluminum alloy rotors, oil sump grooves cannot be formed at the time of powder molding unlike conventional iron-based sintered rotors due to restrictions on the manufacturing method, so a new oil sump groove processing step was added. I have to do it. As a machining method, end mill machining or electric discharge machining can be considered, but there is a problem that the equipment is expensive and machining is expensive.
In addition, in the end milling, the degree of freedom in providing the groove shape is small.

An object of the present invention is to solve the above problems, and an object of the present invention is to economically manufacture a rotor made of an aluminum alloy for a vane rotary type compressor having an oil sump groove on a rotor end face. .

[Means for solving the problem]

The present invention provides a method for easily and inexpensively forming an oil sump groove of an aluminum alloy rotor by forming an oil sump groove on an end face of a rotor that slides with a side plate in a range of 0.1 to 2.0 mm. Using a metal mold having a tangent angle of 30 to 75 ° with respect to the engraving direction on the side surface of the protrusion, and press-marking the concave groove portion at a warm temperature to provide a method. Is what you do.

In a preferred embodiment of the present invention, the aluminum alloy used as the material of the rotor needs to have low thermal expansion in order to stabilize the clearance with other components constituting the compressor with high precision, and it is necessary to have abrasion resistance. It is necessary to contain Si in an amount of 12 to 30% by weight because it is necessary to have high stiffness and high stiffness. .
It is desirable to contain 5 to 5.0% by weight and 0.2 to 2.0% by weight of Mg. Further, in order to improve heat resistance, wear resistance or mechanical properties as needed, 1.0 to 10.0% by weight of a transition element such as Fe, Ni, Mn is contained.

The above pressure stamping is usually heated to 150-450 ° C to soften the rotor itself, and the depth of the oil sump groove is generally 2.
0 mm or less.

FIGS. 2 (A) and 3 (A) are cross-sectional views each showing an example of a mold used for stamping an oil reservoir groove as shown in FIG. 1 with pressure. ) And FIG. 3 (B) are conceptual diagrams showing the shape of the oil sump groove obtained by the mold, respectively. Here, FIG. 2 (A) shows a curvature radius R representing a tip shape of a mold projection and a tangent angle θ of a side surface of the projection.
It is shown.

[Action]

Hereinafter, the above-mentioned composition range of the aluminum alloy which is the material of the rotor conforming to the present invention will be described. The aluminum alloy may be either a powder sintered alloy or a continuous cast alloy.

Si, which is a main additive element, is an element effective for decreasing the expansion coefficient and improving wear resistance and rigidity by increasing the content. If the content is less than 12% by weight, the coefficient of thermal expansion is high and the wear resistance is not sufficient. If the content exceeds 30% by weight, the ductility of the material is deteriorated and the notch toughness value of the rotor is reduced. It is preferable that the content is not less than 30.0% by weight and not more than 3% by weight. If the content is less than 12% by weight, the deformability of the material is large, so that it is not necessary to perform warm stamping, which is one of the features of the present invention. If the content exceeds 30% by weight, the ductility of the material is reduced. In addition, cracks are easily generated by stamping. Also from this viewpoint, the Si content is desirably 12.0% by weight or more and 30.0% by weight or less.

Cu and Mg are age hardening elements for increasing the strength and hardness of the alloy. Cu content less than 0.5% by weight, M
If the g content is less than 0.2% by weight, sufficient strength and hardness cannot be obtained. When the Cu content exceeds 5% by weight or when the Mg content exceeds 2% by weight, coarse precipitates are formed and the strength is deteriorated, and the thermal stability is lowered. Therefore, the Cu content is 0.5-5.0% by weight and the Mg content is 0.2-2.0%.
% By weight.

If necessary, a transition element such as Fe, Ni, or Mn is contained in order to improve heat resistance, wear resistance, or mechanical properties. However, if the content is less than 1.0% by weight, the effect is small. .
If the content exceeds 0% by weight, the toughness of the material is reduced, the reliability of the material is lost, the deformability is reduced, and cracks are easily generated by stamping. Therefore, the content of these transition elements is adjusted to 1.0 to 10.0.
% By weight.

When stamping an oil sump groove on a rotor having the above composition, since a large amount of Si or a transition element that reduces the ductility of the material is contained, cracking or cracking occurs in stamping in the cold state. .

Therefore, it is necessary to perform stamp forming in a state where the material is heated and softened. The heating temperature depends on the composition of the material and the required properties of the oil sump groove.
Desirably, it is heated to 150 to 450 ° C. If the temperature is lower than 150 ° C., cracks and cracks are generated, and a large deformation resistance and a high pressing force are required. If the temperature exceeds 450 ° C., the material is annealed, precipitates such as Si crystals and crystallized substances become coarser than necessary, and the material deteriorates, and the specifications of peripheral equipment become high-grade. Therefore, the heating temperature of the rotor itself for pressure stamping is 15
Desirably, the temperature is 0 to 450 ° C.

Next, the range limitation of the shape of the protrusion of the mold will be described.

As described above, since the rotor material contains a large amount of Si, a transition element, or the like that reduces ductility, cracks and cracks are likely to occur even in warm stamping. In particular, if the tip R of the projection is less than 0.1 mm, cracks and cracks are likely to occur.
On the other hand, if the tip R exceeds 2.0 mm, a large pressing force is required to sufficiently secure the depth of the oil sump groove, and the amount of deformation in the pressing direction and the vertical direction increases, and the rotor It deforms around the vane groove, narrowing the vane groove width and deteriorating dimensional accuracy. Therefore, the tip shape R of the protrusion of the mold is preferably 0.1 to 2.0 mm.

If the tangent angle on the side surface of the protrusion of the mold is less than 30 °, the swelling toward the rotor end face side becomes large, and the tip portion and the rotor material bite. Exceeding 75 mm, tip R
Since the same problem as in the case of a large shape occurs, the tangent angle of the protrusion of the mold is set to 30 ° to 75 ° with respect to the marking direction.

Also, if the groove depth obtained by stamping exceeds 2.0 mm, cracks and cracks are likely to occur, and the material will move to the end face and around the vane groove due to plastic deformation and the dimensional accuracy will not be obtained, so it is usually The maximum depth of the oil sump groove is 2.0mm.

〔The invention's effect〕

As described above, according to the present invention, the oil sump groove on the aluminum alloy rotor end face of the compressor is hot-pressed and stamped into the concave groove portion, so that simple work can be performed using a simple press facility. Molding can be performed at low cost and with good material yield.

〔Example〕

Table 1 shows the results of experiments in which 15 types of powdered sintered aluminum alloys and 2 types of continuously cast aluminum alloys were prepared as rotor materials and the engraving molding conditions were changed. That is, Sample Nos. 1 to 21 are powder sintered alloys,
Nos. 22 to 29 are continuous cast alloys.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a vane rotary type compressor rotor, FIG. 2 (A) and FIG. 3 (A).
FIGS. 2A and 2B are cross-sectional views showing examples of dies used for stamping oil sump grooves as shown in FIGS. 1 and 2, respectively. FIGS. 2B and 3B show the dies, respectively. It is a conceptual diagram which shows the shape of the oil sump groove obtained by this.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F04C 18/356 F04C 29/00 B22F 3/24

Claims (3)

(57) [Claims] 1. A concave oil sump groove is formed on an end face of a rotor that slides with a side plate, a tip R of a projection is in a range of 0.1 to 2.0 mm, and a tangent angle of a side face of the projection is 30 degrees with respect to a marking direction.
A method of forming an oil sump groove on an end face of a rotor made of an aluminum alloy for a vane rotary type compressor, wherein the stamping is performed at a warm pressure using a mold of up to 75 °. 2. The aluminum alloy according to claim 1, wherein the aluminum alloy comprises Si: 12 to 30% by weight Cu: 0.5 to 5% by weight Mg: 0.2 to 2% by weight Transition element: 1 to 10% by weight Al: balance the method of. 3. The method according to claim 1, wherein the pressure stamping is performed at a rotor temperature of 150 to 450 ° C.