JPS61286030A - Formation of cylindrical body with large diameter part on inner surface - Google Patents

Abstract

PURPOSE:To reduce and simplify the process by fitting externally a rigid ring to the outside of a formation corresponding part of a large diameter part of the inner surface in a cylindrical coarse section, and bringing the formation corresponding part of said large diameter part to a spinning work with ironing. CONSTITUTION:A coarse section 30 is fitted and installed to the main body part 24c of a mandrel 24, its front end face is made to abut on a stepped part 24b, and the rigid ring 25 fitted externally to both end parts of the coarse section 30 is positioned so as to correspond roughly to the formed part of a small diameter part 31a. Subsequently, the part between the rings 25, 25 is brought to spinning with ironing by a roller 8, and in a state that both end parts of the coarse section 30 are held by the ring 25, a material between both the rings 25, 25 is made to flow backward and brought to drawing, and in that case, a gap is generated against the main body part 24c. Accordingly, in a cylindrical body formed part 31, the small diameter part 31a, and a large diameter part 31b are formed in accordance with the external fitting part of the ring 25, and in accordance with between both the rings 25, 25, respectively. According to such a method, the cylindrical body formed part 31 can be formed by one process with one arrangement.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention involves pressing a roller 2 against the outer periphery of a cylindrical rough-shaped material fitted onto a mandrel, and rotating the roller relative to the mandrel. The present invention relates to a method for forming a cylindrical product having a large-diameter portion on the inner surface by so-called iron spinning forming, in which the rough-shaped material is stretched while moving the material and relatively displaced in the axial direction.

(Prior art) Fig. 2 is an explanatory diagram of a conventionally commonly used spinning forming machine, and Fig. 3 shows a conventional method of forming a cylindrical body with a large diameter portion on the inner surface using this spinning forming machine. It is an explanatory diagram.

Mainly in Fig. 2, 1 is the bed of the molding machine, 2 is a gear box integrated with this bed, 3 is a spindle supported by this gear box, and spindle 3 is connected to the gear in gear box 2 by a motor (not shown). Rotationally driven through. It is fitted onto the spindle 3 with a 4-hard drill.

As shown in FIG. 3, this mandrel is formed from a large-diameter base end 4a and a small-diameter main body 4C extending from the base end via a step 4b. The diameter is determined based on the inner diameter of the large diameter portion to be formed on the inner surface of the cylindrical product. 5 is a tail stock for supporting the rear end (right end in the drawing) of the mandrel 4.

A saddle 6 is engaged with the bed 1 and can slide parallel to the rotation axis of the mandrel 4. The saddle 6 is driven toward the gear box 2 by a feeding means (not shown), and is moved forward by the feeding means (not shown). It is possible to move back. T represents, for example, three brackets supported by the saddle 6, and 8 represents a roller supported by each of the brackets 1. These brackets can be pushed out toward the rotational axis by a pressing means not shown.

Incidentally, some spinning molding machines include one in which the spindle 3 is fixed and the set of rows 28 is rotated, and one in which the saddle 6 is fixed and the spindle 3 is fed.

The process of forming the cylindrical product using the spinning forming machine will be explained mainly with reference to FIG.

In FIG. 3, 10 is a thick-walled short cylindrical rough-shaped member that can be fitted onto the mandrel main body 4C. Figure 0 shows a cylindrical product 13, and the distance 210 from both ends is the inner diameter D.
Small diameter part 13a of l, middle! The section No. 2 is the large diameter portion 13b with the inner diameter D2.

First step: As shown in FIG. 3, the rough profile 10 is fitted onto the mandrel main body 4C, its front end surface (left end surface in the drawing) is brought into contact with the stepped portion 4b, and the mandrel 4 is driven to rotate. The position of the saddle 6 is adjusted to place the roller 8 at the distance l from the rear end of the rough section 10. Next, the suppressing means of the bracket 7 is activated to press the roller 8 against the outer periphery of the rough section 10, and the feeding means of the saddle 6 is activated so that the roller 8 is placed at the distance 131 from the front end of the rough section. Move it back and forth until it reaches . At this point, the roller 8 is released from the pressed contact and is caused to move back. When this reciprocating motion is repeated, the rough section 1
The material of 0 is squeezed and extruded backwards, and the middle part is stretched and becomes thinner, as shown in ω) in the same figure.1 Igneous product 11
is formed.

2nd step: 1. Remove the igneous product 11 and the mandrel 4, and replace the main body 4b (as shown in the figure (O) with another mandrel 4' with a smaller diameter. Also, prepare the side plate 9. 9
consists of, for example, three vertically divided members, and the mandrel main body Acl can be enclosed by these members as a whole. In this state, 91 is a large diameter part of the split plate 9 formed corresponding to the intermediate section 12 of the cylindrical product 13, 9b, 9b are small diameter parts formed on both sides of this large diameter part, and 9b is a small diameter part formed on both sides of this large diameter part. diameter to 1
Next, the inner diameter of the product 11 and the outer diameter of the small diameter portion 9b are made to correspond to the inner diameter of the small diameter portion 13a in the cylindrical product.

Third step: As shown in FIG. 3 (Q), one igneous product 11 is fitted into the mandrel main body portion 4cI through the cut 9, and its front end surface is brought into contact with the stepped portion 4b'Ic.Next, the first step Following the same procedure, the rear end portion of the first igneous product 11 is spun into the row 281C.As a result, this portion is dropped into the small diameter portion 9bK, and the second igneous product 12 is formed.

Fourth step: The second igneous product 12 is turned over with the 2wariya 9, and its front end (rear end when turned over) is subjected to the same spinning process as in the third step. As a result, a cylindrical product 13 as shown in FIG. 3(c) is obtained.

Thereafter, the outer periphery and end face of the cylindrical product 13 are subjected to necessary machining, and the small diameter portions 13a, 13a are precisely machined and the shaft body is inserted therein. In this case, the large diameter portion 13b forms a relief portion.

(Problem) Iron spinning forming is an extremely advantageous method in that it can easily form a cylinder with high product accuracy and a good material structure. As can be seen from the above explanation, when trying to mold a body, many steps and accompanying set-up changes are required, resulting in a high cost of the finished product.

Therefore, an object of the present invention is to reduce the number of steps while taking advantage of the above-mentioned advantages of the method.

(Means of the present invention) The means of the present invention for solving the above-mentioned problems is to fit a rigid ring outside the forming corresponding part of the large diameter part in the cylindrical rough profile material, and to form the forming corresponding part of the large diameter part. This process involves ironing and spinning.

(effect) The present invention will be described in detail with reference to FIG. 3 (6).

As mentioned above, when the material of the rough section 10 is extruded backwards and stretched, the core material flows from the outside to the inside while being squeezed by the rollers 8, and the inner material flows along with the flow. Since it is pulled outward, a gap d is created between it and the mandrel main body 4c as the molding progresses. The backs of both ends of the rough profile are squeezed and reduced in diameter, resulting in a tapered shape as shown in the drawing, and there is also a gap d here.
' occurs.

Based on the above background, the present invention provides a spinning process in which a rigid ring is fitted outside the part corresponding to the formation of the large diameter part, in this example, both ends of the rough profile 10, and the part corresponding to the formation of the large diameter part 13b is attached. As a result, a gap d is created in the processed part and its inner diameter is expanded,
Further, the deformation of both ends is prevented by rigid rings fitted thereon. As a result, a small diameter portion is formed on the inner surface corresponding to the ring, and a large diameter portion is formed corresponding to the above-mentioned processed portion.

(Example) Figure 1 (2) shows a state in which the setup for ladder spinning molding has been completed, and (2) in the same figure shows a state in which the molding process has been completed and a cylindrical product 31 has been obtained.

In FIG. 1 (4), 24 is a mandrel, and the second
It is attached to the spinning molding machine shown in the figure and rotated by the spindle 3. The mandrel 24 is formed from a large-diameter base end 24m and a small-diameter main body 24e extending from the base end via a step 24b-t.

30 is a thick-walled short cylindrical rough-shaped material, and the mandrel main body 24
c K can be loosely fitted. The inner diameter of the rough profile 30 is determined to be substantially equal to the outer diameter of the mandrel main body portion 24c and the inner diameter D1 of the small diameter portion 31a of the cylindrical product 31. 25.2
Reference numeral 5 designates a rigid ring that is fitted onto both ends of the rough profile 30, and is positioned so as to substantially correspond to the formation of the small diameter portions 31a, 31a.

The rough profile 30 is fitted onto the mandrel main body 24c, its front end surface is brought into contact with the step 24b, and in the same manner as the conventional first step, it is inserted between the a-ra 8 and the sill 25.25. Stretch and spin. Therefore, the material between the rings 25, 25 flows rearward and stretches the rough section 30 while its both ends are held in shape by the rings 25, 25, and at this time, as described above, a gap is created between the entire mandrel main body 24c. arise.

Therefore, the cylindrical product 31 is formed with small diameter portions 31 a and 31 a corresponding to the outer fitting portions of the rings 25 and 25, and a large diameter portion 31 b between the rings.

That is, the cylindrical product 31 can be formed in one step with one set-up, and in addition, troublesome tools such as the split mold or another mandrel are not required.

(Effects) As explained above, according to the present invention, when forming a cylindrical product with a large diameter portion on the inner surface by ironing and spinning, the process can be extremely simplified, thereby reducing the cost of the product. be able to. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the process of the present invention, FIG. 2 is a perspective view of a main part of a spinning molding machine used in the present invention and the conventional method, and FIG. 3 is an explanatory diagram of the conventional process. 4.4', 24... Mandrel 8... Roller for ironing 10.30... Rough shaped material 13, 31... Cylindrical body product 13b, 31b... Large diameter part 25... Ring Patent applicant: Nissan Motor Co., Ltd.

Claims (1)

[Claims] In a method for forming a cylindrical product having a large diameter portion formed on the inner surface by fitting a cylindrical rough shape into a mandrel and performing ironing and spinning from the outer periphery of the rough shape, the cylindrical rough shape is A method for forming a cylindrical product, in which a rigid ring is externally fitted outside the portion corresponding to the formation of the large diameter portion in the shape material, and the portion corresponding to the formation of the large diameter portion is provided with a large diameter portion on the inner surface.