JPH03242490A - Molding method for oil sump groove on edge of aluminum alloy rotor - Google Patents

Abstract

PURPOSE:To economically manufacture an aluminum alloy rotor by forming an oil sump groove on a rotor edge in slidable contact with a side plate in a pressure stamping process at a warm temperature. CONSTITUTION:A recessed oil sump groove A is molded on a rotor edge in slidable contact with a side plate, using a pressure stamping process at a warm temperature. In this case, an aluminum alloy comprises 12 to 30wt.% of Si, 0.5 to 5wt.% of Cu, 0.2 to 2wt.% of Mg, 1 to 10wt.% of a transition element and aluminum as a rest. Pressure stamping is applied when a rotor temperature is within 150 to 450 deg.C. As aforementioned, the oil sump groove A on the edge of the aluminum alloy rotor is made in the form of a recess in the pressure stamping process. According to the aforesaid construction, the oil sump groove A can be molded more easily, less expensively and yet with a good material yield, using simple press facilities.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement of an aluminum rotor for a vane rotary type compressor, and particularly to a method for forming oil sump grooves for preventing seizure in a lightweight aluminum alloy rotor. It is.

[Conventional technology]

The rotor of a compressor used in 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 the inner wall surfaces of side plates fixed to both sides of the cylinder block. Cooling gas is drawn into a compression chamber partitioned by five parts: a rotor vane, a cylinder block, and both side plates, and is then discharged after being compressed. The compression chamber requires airtightness, so the clearance between each part is designed to be extremely small.
In particular, the rotor and side plates slide while being subjected to compressive force, making them susceptible to seizure.

Conventionally, rotors have been made of steel or iron-based sintered alloys, and side plates have been made of flake graphite cast iron or iron-based sintered alloys.

In combinations of iron-based materials, the wear resistance of the materials is relatively good, and flake graphite cast iron and sintered alloys have excellent oil retention, so the problem of seizure was not as serious, but in some cases, Oil sump grooves were provided on one or both sides of the rotor to prevent seizure.

In recent years, the need for lighter compressors has increased, and the use of aluminum instead of iron-based materials has been considered. With the development of powdered aluminum alloys made from rapidly solidified powder and high-strength aluminum materials made possible by advances in continuous casting technology, it has become possible to use aluminum for rotors, which was previously not possible with aluminum materials. The side plates can also be made of aluminum by using AI-high Si materials such as A390 material. These alloys are wear resistant and
Despite containing a large amount of alloy components such as Si to improve seizure resistance and maintain a high level of clearance accuracy, the seizure resistance between the rotor and side plate is insufficient, especially on the sliding surface. Seizure easily occurs when the oil runs out, so an oil sump groove on the end face of the rotor is essential.

[Problem to be solved by the invention]

However, in the case of aluminum alloy rotors, due to constraints in the manufacturing process, it is not possible to form oil sump grooves during powder molding as with conventional iron-based sintered rotors, so a new process for forming the oil sump grooves has been added. I have to. Possible machining methods include end mill machining and electrical discharge machining, but these have the problems of high-grade equipment and expensive machining. Furthermore, in end milling, the degree of freedom in forming the groove shape is small.

The present invention aims to solve the above-mentioned problems, and aims to economically manufacture an aluminum alloy rotor for a vane rotary type compressor having an oil sump groove on the end face of the rotor. .

[Means to solve the problem]

The present invention provides an oil sump groove in an aluminum alloy rotor.
The present invention provides a simple and inexpensive method of forming an oil reservoir groove on the end face of a rotor that slides on a side plate by warmly stamping a concave groove under pressure. .

In a preferred embodiment of the present invention, the aluminum alloy used as the material for the rotor needs to have low thermal expansion in order to stabilize the clearance with other parts constituting the compressor with high precision, and is resistant to wear. sex,
Since it is necessary to have high rigidity, it is desirable to contain 12 to 30% by weight of Si, and if necessary, Cu, which is an age hardening element, is added to increase the strength and hardness.
0.5-50% by weight and Mg 0.5-50% by weight
It is desirable that it be included.

Furthermore, in order to improve heat resistance, wear resistance, or mechanical properties as required, transition elements such as Pe, Ni, and Mn are contained in an amount of 1.0 to 10.0 wt%.

The above pressure stamp is usually heated to 150 to 450 degrees Celsius in order to soften the rotor itself, and the mold used to form the oil reservoir groove at that time has a protrusion tip shape R of 0.
．． It is preferably in the range of 1 to 2.011 m, and the tangential angle of the side surface of the protrusion is 30 to 75 m with respect to the marking direction.
Preferably. The depth of the oil sump groove is generally 2.
0 mm or less.

Figures 2 (^) and 3 (A) are cross-sectional views showing examples of molds used for pressure stamping oil sump grooves as shown in Figure 1, and Figure 2 (B). ) and Figure 3 (B)
2A and 2B are conceptual diagrams showing the shapes of oil sump grooves obtained by the above-mentioned molds, respectively. FIG. 2 (^) shows the radius of curvature R representing the shape of the tip of the mold protrusion and the tangent angle θ of the side surface of the protrusion.

[Effect]

The above composition range of the aluminum alloy, which is the material of the rotor suitable for the present invention, will be explained below. The aluminum alloy may be either a powder sintered alloy or a continuously cast alloy.

Si, which is a main additive element, is an element that is effective in lowering the expansion coefficient and improving wear resistance and rigidity by increasing the content. If the Si content is less than 12 wt%, the coefficient of thermal expansion will be high and the wear resistance will not be sufficient. If the content exceeds 30 wt%, the ductility of the material will deteriorate and the notch toughness value of the rotor will decrease. Therefore, the Si content is 12.0 wt%. % or more 30
．． 0 wt% or less is preferable. In addition, if the content is less than 12 wt%, the deformability of the material is large, so there is no need for warm stamping, which is one of the features of the present invention, and if the content exceeds 30 wt%, the ductility of the material decreases, so the stamping Cracks are more likely to occur due to molding. From this point of view, the Si content is 12.
It is desirable that the content is 0 wt% or more and 30.0 wt% or less.

Cu and Mg are age hardening elements for increasing the strength and hardness of the alloy. Cu content is 0.5wt%
If the Mg content is less than 0.2 wt%, sufficient strength and hardness cannot be obtained. When the Cu content exceeds 0.5 wt% or when the Mg content exceeds 0.2 wt%, coarse precipitates are formed, which not only deteriorates the strength but also reduces thermal stability. Therefore, the Cu content is set to 0.5 to 5.
It is desirable that the Mg content is 0.2 to 2.0 wt%.

Transition elements such as Re, Ni, and Mn are included to improve heat resistance, wear resistance, or mechanical properties as necessary, but if the content is less than 1.0 wt%, the effect is small. If it exceeds 10.0 wt%, the toughness of the material decreases, the material becomes unreliable, deformability decreases, and cracks are more likely to occur due to stamping. Therefore, the content of these transition elements should be set at 1.0 to It is preferable to set it to 10.0 wt%.

When stamping oil reservoir grooves on a rotor with the above composition, cold stamping may result in cracks and cracks as the material contains a large amount of Si or transition elements that reduce the ductility. .

Therefore, it is necessary to heat and soften the material before stamping it. The heating temperature varies depending on the composition of the material and the required oil sump groove, but when the rotor itself is 1.
It is desirable that the temperature is 50 to 450°C. 15
If the temperature is less than 0°C, cracks and cracks will occur, and the deformation resistance will be large, requiring a high pressing force. If the temperature exceeds 450° C., the material may be annealed, precipitates such as Si crystals may become coarser than necessary, and the quality of the material may deteriorate, and the specifications of peripheral equipment may become higher-grade. Therefore, it is desirable that the heating temperature of the rotor itself for pressure stamping is 150 to 450°C.

Next, limiting the range of the shape of the protrusion of the mold will be explained.

As mentioned above, since the rotor material contains a large amount of Si or transition elements that reduce ductility, cracks and cracks are likely to occur even during warm stamp forming. In particular, if the tip R of the protrusion 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 will be required to ensure a sufficient depth of the oil reservoir groove, and the amount of deformation in the direction perpendicular to the pressing direction will increase. It deforms the area around the vane groove of the rotor, narrowing the vane groove width and worsening dimensional accuracy. Therefore,
It is preferable that the tip shape R of the protrusion of the mold is 0.1 to 2.0 mm.

If the tangential angle of the side surface of the protrusion of the mold is less than 30°, the protrusion toward the end surface of the rotor becomes large, causing the tip and the rotor material to bite. If the angle exceeds 75°, the same problem as when the tip radius shape is large will occur, so it is desirable that the tangential angle of the protrusion of the mold is 30° to 75° with respect to the marking direction.

In addition, the groove depth obtained by stamping molding is 2.0 mr.
Normally, the oil sump groove depth should be set to 2.0 mm, because if it exceeds n, cracks and cracks are likely to occur, and the material will move to the end face or around the vane groove due to plastic deformation, making it impossible to obtain dimensional accuracy.
0 mm is the limit.

[Effects of the Invention] As explained above, according to the present invention, the oil sump groove on the end face of the aluminum alloy rotor of the compressor is stamped with a warm concave groove using simple press equipment. It has become possible to mold with simple operations at low cost and with a high material yield.

〔Example〕

Table 1 shows the results of experiments conducted using 15 types of powder sintered aluminum alloys and 2 types of continuously cast aluminum alloys as rotor materials, and varying the stamping forming conditions. That is, samples Nα1 to 21 are powder sintered alloys, and samples N (122 to 29 are continuously cast alloys).

[Brief explanation of drawings]

Figure 1 is a conceptual diagram showing a vane rotary type compressor rotor, Figure 2 (^)'J3 and Figure 3 (
^) is a sectional view showing an example of a mold used for pressure stamping an oil sump groove as shown in Fig. 1, and Fig. 2
FIG. 3(B) and FIG. 3(B) are conceptual diagrams showing the shape of the oil sump groove obtained by the above mold, respectively.

Claims (3)

[Claims] (1) An oil sump groove on the end face of an aluminum alloy rotor for a vane rotary type compressor, which is characterized by forming a concave oil sump groove on the end face of the rotor that slides on the side plate by warm pressure stamping. molding method. (2) Aluminum alloy is Si: 12-30% by weight Cu: 0.5-5% by weight Mg: 0.2-2% by weight Transition element: 1-10% by weight Al: remainder The method according to claim (1), comprising: (3) The method according to claim (1), wherein the pressure stamping is performed at a rotor temperature in the range of 150 to 450°C.