JP2518980B2 - Method for drilling precision aluminum alloy product with holes - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole machining method for finishing a hole of a precision aluminum product having a hole having a bottom and a vertical inner wall with a high dimensional accuracy by cold forging.

[0002]

2. Description of the Related Art For example, like a receiving plate having a hole for press-fitting a piston of a compressor and supporting the piston as a whole, a hole having a high dimensional accuracy and having a bottom and a vertical inner wall surface is required. In the drilling of precision aluminum alloy products we have, semi-finished products with a shape close to the product dimensions are processed by warm forging or hot forging, and the holes of this semi-finished product are finished by cutting with a ball end mill etc. It was
This is because warm forging (for example, 150 to 300 ° C.) and hot forging (for example, 350 to 500 ° C.) can process rough hole dimensions, but cannot improve dimensional accuracy.

[0003]

Conventionally, since the hole portion of the semi-finished product processed by warm forging or hot forging has been finished by cutting, it takes a lot of time and labor to cut the cost. Also, for example, when the hole bottom is a concave spherical surface,
Alternatively, as described in the examples, in the case of a hard aluminum alloy having high strength and abrasion resistance (for example, an Al-Si alloy), there is a drawback that the cutting process becomes more difficult and the cost becomes higher. An object of the present invention is to provide a method for drilling a precision aluminum product, which solves the problem of such drilling and enables more efficient drilling with high dimensional accuracy.

[0004]

The method of the present invention for achieving the above-mentioned object is a hole drilling method for precisely finishing a hole of a precision aluminum alloy product having a bottom and an inner wall having a vertical hole by cold forging. Therefore, first, an aluminum alloy blank obtained by slicing an extruded material is formed into a hole having an approximate size by warm forging at a temperature of 150 to 300 ° C., then this is annealed, and then cold forged to a predetermined precision. A method of drilling a precision aluminum product having a hole characterized by finishing the hole to a size.

[0005]

The present invention will be described in detail below. In the hole drilling method according to the present invention, first, an aluminum alloy blank material obtained by slicing an extruded material is formed into a semi-finished product by warm forging into the approximate size of a hole, which is a semi-finished product. As shown in FIG. 1, the core 11 of the mold die is pushed into the blank material 41 to perform the molding process into the approximate size of the predetermined hole. Here, the reason why the extruded material is sliced and used as the aluminum alloy blank material instead of the casting as in the embodiment is that the extruded material has fewer defects on the surface and inside of the material.

Further, the reason why warm forging is adopted for the hole processing is that the hole is easily formed and the die (die core 11) does not need a draft. In addition, generally 3
Forging at 00 ° C or lower is called warm forging, and forging at a temperature over 300 ° C is called hot forging. In the case of hot forging, the temperature is high, so even if the surface of the blank material is lubricated, it is lubricated. Is not effective and requires a draft in the die used for hot forging, and this draft cannot be corrected during the subsequent cold forging, so it is not possible to machine a hole with a vertical portion on the inner wall. . Therefore, in the present invention, warm forging is adopted.

If the temperature of the warm forging is less than 150 ° C., it is difficult to form the hole, and if it exceeds 300 ° C., the effect of the lubricant applied to the surface of the blank material is lost and the die (the die of FIG. The core 11) does not come off, and a draft is required for the mold. If the wall surface of the hole is sloped, the final cold forging cannot finish the hole whose inner wall is vertical to a predetermined size. Therefore, the warm forging temperature is 150 to 300 ° C.
And The temperature for warm forging is selected according to the hardness of the aluminum alloy as a material and the complexity or size of the hole shape. Generally, for soft materials, and when the required dimensional accuracy is relatively low, low temperatures are selected, and vice versa.

The semi-finished product which has been hole-formed by warm forging as described above is then annealed, in order to recrystallize and soften the work-hardened material by warm forging. As this annealing condition, a condition that is usually performed is adopted. In the present invention, the inner wall is then finished by vertical cold forging into a hole having a predetermined precision dimension, and no further processing is required. The dimensional accuracy after cold forging is, for example, about ± 0.06 mm or less of the design dimension, as will be apparent from the examples described later.

According to the hole drilling method of the present invention, the hole portion of the semi-finished product machined by warm forging has an approximate shape and size (for example, 85% of the designed size), but this is cold forged. By doing so, the dimensional accuracy of the hole is corrected (for example, 15% of the designed size), and a precise product having a hole with a very small error from the designed size is mass-produced without cutting. In addition, the plastic working during cold forging increases the strength and wear resistance of the hole portion.

[0010]

1 and 2 show examples of forging dies (die 1, die core 11, punch 3, etc.) used in the examples of the method of the present invention, and FIGS. 3 and 4 show the present invention. FIGS. 3 and 4 respectively show an aluminum alloy product with a hole to be machined in the embodiment of the method, and the product 4 in FIGS. 3 and 4 is a ring-shaped receiving member for receiving a piston of a compressor (not shown) in an automobile air conditioner, and is shown on an outer periphery thereof Do not press the holes 4a for press-fitting the pistons of the compressors at equal angles (approximately 7
The holes 4b are provided at intervals of 2 degrees and have a punched hole 4b in the center, and the hole 4a has a concave spherical inner bottom.

The diameter L of the product 4 in FIG. 4 is 97 mm,
The diameter l of the hole 4b is 35 mm, the diameter of the circle connecting the centers of the holes 4a is 75 mm, the diameter R of the hole 4a is 14.3 mm, the vertical wall depth d1 of the hole 4a is 5.5 mm, and the inside of the concave spherical surface is The bottom radius d2 is designed to be 7.15 mm.

Molds for forging are SKD-11 and SKH-
It is made of a steel material approximately in the middle of No. 9, and is composed of a die 1, a punch 3 and the like fixed on a machine base 10. The die 1 has a core 11 for forming the hole 4a of the product 4, a knockout pin 2 is provided at the center, and a knockout hole for flushing the material is provided at the center of the upper part of the knockout pin 2. 20 are formed.

An embodiment of the method of the present invention will be specifically described below. First, an A4032 alloy containing 10% silicon (Al
-12% Si-1.0% Mg alloy), an aluminum alloy having a composition close to that of (12% Si-1.0% Mg alloy) was extruded to form a hollow rod having a diameter of approximately 100 mm, and the hollow rod was sliced to a thickness of about 16 mm.
Blank material 41 is manufactured.

After applying a lubricant composed of sodium metal soap to the surface of the material 41 (film thickness of about 1 micron), this is supplied into a furnace (not shown) and heated to about 300 ° C., and then, as shown in FIG. 2 into the die 1, and the punch 3 applies a pressure of about 63 kg / mm ^{2 for} about 0.5 seconds.
The semi-finished product 40 of 1. is warm forged. This semi-finished product 40 is
After the warm forging, the die 1 is knocked out and cooled to room temperature. This warm forging die (die 1 and punch 3
3) is set to be slightly larger than the size of the product 4 in FIGS. 3 and 4, but the semi-finished product 40 is reduced by cooling, and the semi-finished product 40 with a dimensional accuracy of about 85% of the design size is obtained. Is manufactured.

Next, the semi-finished product 40 is supplied into a furnace (not shown), annealed at about 320 ° C. for about 2 hours, and then gradually cooled to room temperature over about 8 hours.

After the cooling, the surface of the semi-finished product 40 is lubricated in the same manner as the above-mentioned lubrication process, and another mold having the same structure as the mold of FIG. The cold forging by pressing at the same pressure as that in the warm forging for the same time at room temperature for about 15% to correct the shape and dimension and plastic working, and the extruded flash shown in FIG. A product 4 was manufactured by cutting a portion 42 with a press (not shown).

When 30 products 4 were manufactured by the above procedure, the vertical wall depth d1 of the hole 4a was ± 0.06 m, which is the design value.
m or less, the radius d2 of the concave spherical bottom of the hole 4a is within +0.025 mm of the design value, and the diameter R of the hole 4a is + of the design value.
Within 0.02 mm, center distance between holes 4a is ± 1 of design value
It was less than 0 '. In addition, the semi-finished product is processed by warm forging or hot forging, and the mass productivity is much improved as compared with the case where the hole portion of the semi-finished product is cut and the required dimensional accuracy is secured. The portion 4a had improved strength and wear resistance due to plastic working.

Although the hole 4a of the product 4 is a round hole and has an inner bottom on a concave spherical surface in the above-mentioned embodiment, the method of the present invention can be applied only to the processing of an aluminum alloy product having such a hole 4a. However, it is also effective when processing aluminum alloy products with flat bottom holes, conical bottom holes, polygonal holes, etc. Rather, products with holes of this shape are more suitable for cold forging. Since the piezoresistive force and the amount of deformation are small, it can be processed more precisely and easily. The method of the present invention is not limited to products made of aluminum and aluminum alloys,
For example, it can be applied to the processing of products having precise holes made of copper and its alloys, magnesium and other metals.

[0019]

According to the method of the present invention, a hole is formed into a semi-finished product by warm forging into a semi-finished product, which is then annealed and then cold forged to obtain a hole with high dimensional accuracy. Since it is straightened and plastically worked, mass productivity is much improved compared to the conventional case where the hole size is straightened by cutting, and it is possible to provide aluminum alloy products with holes at low cost. It has a notable industrial effect such that the strength and wear resistance of the hole portion are improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a material is supplied to a forging die used in an embodiment of the method of the present invention.

FIG. 2 is a half sectional view showing a state where a material is pressed in the mold of FIG.

FIG. 3 is a plan view of a precision aluminum alloy product having holes manufactured by the method of the present invention.

FIG. 4 is a sectional view taken along arrow AA in FIG. 3;

[Explanation of symbols]

 1 Die 11 Core 2 Knockout Pin 20 Escape Hole 3 Punch 4 Product 40 Semi-finished Product 41 Blank Material 42 Flash

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-119942 (JP, A) JP-A-2-200334 (JP, A) JP-A-3-9242 (JP, U)

Claims (1)

(57) [Claims] 1. A precision tool having a bottom and an inner wall having a vertical hole.
Precisely finish the hole of the aluminum alloy product by cold forging
This is a drilling method for drilling holes.
Luminium alloy blank at a temperature of 150-300 ℃
Warm forging to form holes with approximate dimensions to produce semi-finished products
Then, this is annealed, followed by cold forging
Precision with holes characterized by finishing to holes with precise dimensions
Drilling method for dense aluminum alloy products.