JP2003136131A - Method for manufacturing hollow member provided with solid-core portion in end side - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a hollow member provided with a solid-core portion in an end side capable of manufacturing the hollow member with a good yield and a less deflected thickness. SOLUTION: An inner face regulating tool 2 is inserted into the hollow portion 20a of a stock material 20 provided with the solid-core portion in the end side of the axial direction of the hollow portion 20a, and, for example, by an inclined rolling mill provided with three pieces of roll 1, a diameter reducing work accompanied by a thickness reducing work is performed at least in the hollow portion 20a to manufacture the hollow member 10 provided with the solid-core portion in the end side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow member having a solid portion on one end side in the axial direction.

[0002]

2. Description of the Related Art A shaft for power transmission of an industrial machine, a shaft of a starter motor of an internal combustion engine, or the like is integrally formed with a gear or serration whose tip diameter is substantially equal to that of the shaft on the outer surface at one end side. There is. Some long bolts are provided with a screw on the outer surface of one end side of a predetermined length. These shafts and bolts are manufactured by integrally forming gears, screws, etc. on the outer surface of one end side of a solid or hollow elongated member by plastic working such as rolling and forging, and machining. .

The solid member and hollow member, which are the materials for the shaft and the like, are manufactured by the following method, for example.

A large-diameter round steel piece or square steel piece that has been heated is
The cross-sectional area is sequentially reduced at a predetermined rolling reduction by the hole type roll row to form a small diameter solid member.

[0005] A heated round steel slab is pierced at its axial center with a piercer to form a hollow shell, which is directly or if necessary subjected to standard rolling with a sizing mill, and then stretch-rolled with a mandrel mill, and further a reducing mill. The diameter of the hollow member is reduced by, and then a refining process is performed to obtain a hollow member having a small diameter.

The plate material is formed into a circular shape by a plurality of forming rolls, and the abutting portions are joined by welding to form a hollow member having a small diameter.

The solid member or hollow member manufactured by the above-mentioned method is subjected to secondary and tertiary processing as required, and then the outer surface at one end side is subjected to plastic working such as rolling and forging, and mechanical working. Thus, for example, a gear is formed into a shaft.

Recently, in order to reduce the weight of the device and to rationalize the cost, it has been attempted to reduce the outer diameter of the shaft or the like by using a high-strength material for the solid member or hollow member. .

A method of manufacturing the shaft as described above is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-5037 and Japanese Patent Application Laid-Open No. 7-18571.
No. 4 publication.

The method disclosed in Japanese Patent Laid-Open No. 3-5037 is a method of forming a gear, for example, on the outer surface of one end side of a solid member by forward extrusion using a mold. However, since the shaft manufactured by this method has a solid overall length,
Not suitable for the purpose of weight reduction.

The method disclosed in Japanese Unexamined Patent Publication No. 7-185714 is a method in which, for example, a gear is heated and formed on one end side of the hollow member when heat treatment is applied to the hollow member to increase hardness and strength. Since the shaft manufactured by this method has a hollow entire length, it is possible to reduce the weight. However, since the gear is formed in the hollow member, the thickness of the portion where the gear is formed is thin, and the strength is inferior to the case where the gear is formed in the solid member. Therefore, when it is repeatedly used, there is a possibility that a crack may occur and break. Further, if the hollow member has a large uneven thickness, the strength of the thin portion is further reduced due to the uneven thickness, and the same problem as described above occurs.

As described above, it is difficult for the shaft manufactured from the solid member or the hollow member to simultaneously achieve the two purposes of weight saving and securing of strength. for that reason,
A shaft manufactured from a hollow member having a solid end at which gears and the like are formed and having a solid end at the other end is used.

When manufacturing a hollow member having a solid portion at its end, conventionally, a hole is drilled from one end side of the solid member, or the solid member and the hollow member are joined by welding or the like. Was. However, in the method of drilling from one end side of the solid member with a drill etc., not only the yield is bad, but when drilling with a small diameter and a long axial direction, bending of the drill or eccentricity causes uneven thickness of the hollow part. Deteriorates and the material strength in the thin portion is reduced due to uneven thickness. Further, in the method of joining a solid member and a hollow member by welding or the like, skill is required to weld them without eccentricity, and the shape of the joint portion of both members is devised to prevent eccentricity. However, there is a problem that the manufacturing cost is high.

A method for manufacturing a shaft from a hollow member having a solid portion at its end is disclosed in Japanese Patent Laid-Open No. 59-197330. This method is a method in which, after cold-drawing an electric resistance welded pipe, the pipe end is made solid by upsetting and a gear is provided at the solid end of the pipe by machining.
In this method, since the drilling process by the drill and the joining of the solid member and the hollow member are not performed, the above problems do not occur. However, since the solid portion is formed by upsetting the electric resistance welded pipe, the entire solid portion is not metallurgically joined. Therefore, the strength of the portion where the gear is formed may be poor.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method which is small in thickness unevenness and can be manufactured with a high yield even when a hollow member having a solid portion on one end side has a small diameter. To do.

[0016]

The gist of the present invention resides in the following method (1), (2) and (3) for manufacturing a hollow member having a solid portion on one end side.

(1) An inner surface regulating tool is inserted into the hollow portion of a material having a solid portion on one end side in the axial direction of the hollow portion, and at least the hollow portion is subjected to a diameter reduction process accompanied by a thickness reduction process. And a method of manufacturing a hollow member having a solid portion on one end side.

(2) The above-mentioned processing is carried out hot by an inclined rolling mill provided with three or four rolls around the pass line, and a solid portion is provided on one end side as described in (1) above. A method for manufacturing a hollow member provided.

(3) The above-mentioned processing is carried out by an inclined rolling machine having three rolls provided around the pass line when the outer diameter reduction ratio B defined by the following formula (1) is 50% or less and the following ( The cross-sectional reduction rate C of the hollow part defined by the formula 2) is 80.
%, The method for producing a hollow member having a solid portion on one end side as described in (2) above.

B (%) = 100 · (OD ₂ −OD ₁ ) / OD ₂ ... (1) C (%) = 100 · (A ₂ −A ₁ ) / A ₂ ... (2) Here And A ₂ = (OD ₂ ² −ID ₂ ² ) A ₁ = (OD ₁ ² −ID ₁ ² ) where OD _{2 is} the outer diameter (mm) of the material OD _{1 is} the outer diameter (mm) after processing ID ₂ : Inside diameter of material (mm) ID ₁ : Inside diameter after processing (mm)

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a shaft member having a solid portion on one end side of a hollow portion (hereinafter referred to as a shaft member) according to the manufacturing method of the present invention will be described with reference to FIGS. It will be explained based on.

FIG. 1 is a partial sectional side view showing an example of the shape of a shaft member manufactured by the method of the present invention.

In the figure, the shaft member 10 has a constant outer diameter OD ₁ over the entire length L ₁ , and a hollow portion 10 a having a predetermined inner diameter ID ₁ , wall thickness T ₁ , and length La _1. A solid portion 10b having a predetermined length Lb ₁ is provided on one end side. The shaft member 10 is a shaft having a gear formed at its one end by machining, for example, a gear on the solid portion 10b.

FIG. 2 is a partial cross-sectional side view showing the shape of the material used in the present invention.

In the figure, the raw material 20 has a constant outer diameter OD ₂ over the entire length L ₂ , and has a long inner diameter ID ₂ , a wall thickness T ₂ , and a length La ₂ at one end of the hollow portion 20 a. Lb ₂
And a solid portion 20b. As will be described later, the material 20 is subjected to a diameter reduction process, and the shaft member 1 shown in FIG.
It is set to 0. Therefore, the length L ₂ of the material 20 and the outer diameter OD
₂ , inner diameter ID ₂ of hollow portion 20a, wall thickness T ₂ and length L
a _2, and the length Lb ₂ of the solid portion 20b is set the size required to the shaft member 10, by a working ratio in the diameter reduction.

The object of the present invention is to reduce the uneven thickness of the hollow portion 10a even if the shaft member 10 has a small diameter. Therefore, it is important to reduce the uneven thickness of the hollow portion 20a of the material 20 as much as possible. When the inner diameter ID ₂ of the hollow portion 20a of the material 20 is small and the length La ₂ is long, the hollow portion 20a is produced at the stage of manufacturing the material 20 described later.
Uneven thickness may worsen.

Therefore, the inner diameter ID ₂ of the hollow portion 20a of the material 20 is set to the hollow portion 10a of the shaft member 10 so that the hollow portion 20a of the material 20 is not affected by uneven thickness. It is preferable to set it to be sufficiently larger than the inner diameter ID ₁ . Further, the wall thickness T ₂ of the hollow portion 20a of the material 20 is set to be larger than the wall thickness T ₁ required for the hollow portion 10a of the shaft member 10. Thus hollow part 2
If the inner diameter ID _{2 of} 0a and the wall thickness T ₁ are set, the material 20 can be formed based on the dimensions of the hollow portion 10a of the shaft member 10.
Since the outer diameter of the hollow portion 20a can be set, this outer diameter may be set as the outer diameter OD ₂ of the material 20.

If the dimensions of the material 20 are set as described above, the diameter reduction processing is performed over the entire length of the material 20 during the diameter reduction processing described later, and the hollow portion 20a of the material 20 is further reduced. Thinning is applied.

The manufacturing method of the material 20 is not limited.
It may be manufactured by a commonly used method. For example,
The following two methods are general manufacturing methods.

One of them is a method of manufacturing by forging or extrusion. That is, after heating a solid billet, for example, it is housed in a vertical container whose inner diameter is slightly larger than the outer diameter of the billet, and after pushing the mandrel from the upper end of this billet for a predetermined length along the axial center. Pull out. As a result, in the portion where the mandrel is pushed in, the hollow portion 20a whose inner diameter ID ₂ corresponds to the diameter of the mandrel
Thus, the material 20 whose outer diameter OD ₂ corresponds to the inner diameter of the container is manufactured over the entire length.

Further, using a vertical container having a die at the bottom, the mandrel is pushed along the axial center by a predetermined length as described above, and then the billet is pushed out together with the mandrel from the die and then the mandrel. Pull out. As a result, the part where the mandrel is pushed in is
Hollow part 20 whose inner diameter ID ₂ corresponds to the diameter of the mandrel
and the outer diameter OD ₂ is equal to the inner diameter of the die, and the raw material 20 is manufactured.

The other one is drilling with a drill or the like.
It is a method of manufacturing. That is, outer diameter OD_TwoSolid
Prepare the material and use one end face of this solid material for drilling etc.
Drilling is performed along the axial center for a predetermined length. This
As a result, the part that has been drilled will have an inner diameter ID_TwoIs the above
A hollow portion 20a corresponding to the diameter of the drill is formed, and the outer diameter is OD. _Two
Is the outer diameter OD before processing over the entire length_TwoMaterial 20 equal to
Manufactured.

When drilling with this drill or the like, the smaller the inner diameter ID ₂ of the hollow portion 20a of the material 20, the smaller the inner diameter ID with respect to the length La ₂ of the hollow portion 20a.
_The smaller the ratio of ₂ (ID ₂ / La ₂ ) is, the larger the uneven thickness is likely to occur. Therefore, it is preferable that the inner diameter ID ₂ of the hollow portion 20a of the material 20 is 20 mm or more, and the ratio of the inner diameter ID ₂ to the length La ₂ of the hollow portion 20a (ID ₂ / La ₂ ) is 0.07 or more. .

After the inner surface restricting tool is inserted into the hollow portion 20a of the material 20, the outer diameter of the material 20 is reduced to form a shaft member 10 having a solid portion 10b at one end of the hollow portion 10a. To be done. This diameter reduction process is based on the material 2
It is applied over the entire length of 0. Thereby, the hollow portion 20a
Is subjected to a diameter reduction process accompanied by a thickness reduction process, the solid portion 20b is subjected to a diameter reduction process, and the hollow portion 20a and the solid portion 20b are stretched to have a predetermined length.

As typical methods of this diameter reduction processing, there are the following rolling method using inclined rolls, rolling method using hole-type rolls, drawing or punching method using dies, and punching method using rolls. Hereinafter, these methods will be described.

Rolling Method Using Inclined Rolls This method is a method of rolling the material 20 onto the shaft member 10 by using an inclined rolling machine provided with three or four rolls around the pass line.

FIG. 3 is a schematic view for explaining a rolling state by the 3-roll type inclined rolling mill, and is a front view seen from the entrance side of the inclined rolling mill. FIG. 4 is a sectional view taken along the line AA in FIG. FIG. 5 is a view on arrow EE of FIG.

In these drawings, a three-roll type inclined rolling mill is composed of three rolls 1 arranged around a pass center (also referred to as a pass line) X and a mandrel which is an inner surface regulation tool arranged on the pass line X. And a bar 2.

The roll 1 has a diameter dr in the middle portion in the axial direction.
The entrance face 1b has a substantially truncated conical shape having a gorge portion 1a of which the roll diameter decreases from the gorge portion 1a toward the entrance side end, and a roll cone of which the roll diameter increases toward the exit side end. It is a cone type having a trapezoidal shape or a cylindrical outlet surface 1c having substantially the same diameter. In this roll 1, the intersection angle γ, the inclination angle β, and the shortest distance Rg from the pass line X to the peripheral surface of the gorge portion 1a (hereinafter, referred to as roll position Rg) are set by a setting mechanism (not shown). The roll 1 is driven to rotate about its axis Y by a drive mechanism (not shown).

The mandrel bar 2 is connected to the thrust block 3 which can move along the path line X, and has a structure rotatable about its axis.

When the material 20 is rolled by the three-roll type tilt rolling machine having such a structure, first, the intersection angle γ, the tilt angle β and the roll position Rg of the roll 1 are set. The crossing angle γ and the inclination angle β of the roll 1 may be the angles that are usually set when manufacturing the seamless pipe. For example, the cross angle γ of the roll 1 is about 0 to 5 degrees, and the inclination angle β is about 3 to 10 degrees.
The roll position Rg is set based on the outer diameter OD ₁ required for the shaft member 10.

Further, the mandrel bar 2 having a predetermined outer diameter dm
Is connected to the thrust block 3. Mandrel bar 2
The outer diameter dm is determined based on the inner diameter ID ₁ required for the hollow portion 10a of the shaft member 10.

Then, the material 20 heated to a predetermined temperature
The solid portion 20b of the thrust block 3 is set to the rolling tip side.
Is moved in the direction of the white arrow shown in FIG. 4 (hereinafter, the movement in this direction is referred to as forward movement) to insert the mandrel bar 2 into the hollow portion 20a of the material 20. Then, after the tip of the mandrel bar 2 reaches the bottom of the hollow portion 20a, the thrust block 3 is further advanced to advance the material 20.

The tip of the raw material 20 is bitten by the inlet surface 1b of the roll 1, and thereafter, the raw material 20 is rotated and moved forward by the rotation of the roll 1, and the diameter reduction processing is started from the solid portion 20b.

The thrust block 3 is advanced even after the diameter reducing process is started, and the mandrel bar 2 is advanced together with the material 20. Thereby, the solid portion 20b of the material 20
Is subjected to diameter reduction processing by a roll 1, and then the hollow portion 2
The roll 0 and the mandrel bar 2 are subjected to diameter reduction processing and wall thinning processing on 0a. After the time when the processing of the hollow portion 20a is started, the thrust block 3 may be advanced to advance the mandrel bar 2 according to the advance speed of the material 20 being rolled, or it may be stopped. However, when stopped, the hollow portion 20a is thinned only in a part of the mandrel bar 2 in the axial direction, and the mandrel bar 2 is partially worn. Therefore, it is preferable to advance the mandrel bar 2 in terms of life. Mandrel bar 2
It is preferable to use the inner surface regulation tool shown in FIG.

FIG. 6 is a side view showing another example of the inner surface regulation tool. The inner surface regulation tool shown in the figure has a structure in which a plug 2b is provided at the tip of a support rod 2a. Plug 2b
Is an outer diameter that is the same as the outer diameter dm of the mandrel bar 2 and is about the length of the region where the hollow portion 20b is rolled by the roll 1. With such a structure, the plug 2b can be, for example, hot work tool steel, and the support rod can be carbon steel.

If the surface of the mandrel bar 2 or the plug 2b may be seized during the processing of the hollow portion 20a, it is preferable to apply a lubricant to these surfaces in advance. The material 20 is rolled in this way,
The shaft member 10 includes a solid portion 10b on one end side of the hollow portion 10a shown in FIG. When the rolling is completed, the mandrel bar 2 is pulled out from the hollow portion 10a of the shaft member 10.

By the way, in the rolling by the above-mentioned three-roll type inclined rolling mill, the raw material 20 is rolled in contact with the three rolls 1 provided around the pass line X. for that reason,
In the cross section perpendicular to the axis of the material 20, the material 2 being rolled
The part of the roll 0 which is not in contact with the roll 1 bulges outward.

If this bulge becomes large, the angle of biting into the roll 1 becomes large, and slippage may occur between the material 20 and the roll 1 during rolling. Also,
In the hollow portion 20b, rolling becomes unstable and eccentric movement occurs,
The uneven thickness of the hollow portion 10a of the rolled shaft member 10 may increase.

Therefore, during rolling, the outer diameter reduction rate B defined by the following equation (1) is set to 50% or less, and the cross-sectional reduction rate C of the hollow portion defined by the following equation (2) is set to 80. % Or less.

B (%) = 100 · (OD ₂ −OD ₁ ) / OD ₂ ... (1) C (%) = 100 · (A ₂ −A ₁ ) / A ₂ ... (2) Here Where A ₂ = (OD ₂ ² −ID ₂ ² ) A ₁ = (OD ₁ ² −ID ₁ ² ) Note that OD ₂ , OD ₁ , ID ₂ and ID _{1 in the} above formula.
Indicates the symbol of the dimension described in FIGS. 1 and 2.

Outer diameter rolling reduction B and hollow area reduction C
The above upper limit of is obtained from the results of the following tests. That is, FIGS.
By the rolling method with the 3-roll type inclined rolling mill described in
The material 20 was rolled into the shaft member 10. Table 1 shows the dimensions of the raw material 20, the dimensions of the shaft member, and the rolling conditions. The results are shown in Table 2.

[0053]

[Table 1]

[0054]

[Table 2]

In the column of rolling conditions in Table 2, ∘ indicates that rolling was possible without problems, and x indicates that the rolling was stopped during rolling. In the column of occurrence of uneven thickness, ◯ indicates that the uneven thickness ratio of the hollow portion 10a of the shaft member is equal to or less than the uneven thickness ratio of the hollow portion 20a of the material 20, and x indicates the hollow portion of the shaft member. The uneven thickness of 10a is the hollow portion 20a of the material 20.
This is the case when it becomes larger than the uneven thickness ratio of. Here, the uneven thickness ratio is a value obtained by dividing the difference between the maximum wall thickness and the minimum wall thickness in the circumferential direction of the hollow portion 10a by the average wall thickness in the circumferential direction, which is expressed in%.

From Table 2, when the rolling reduction of the outer diameter B of the rolled material exceeds 50%, the rolling stops, and when the cross-sectional reduction rate C of the hollow portion exceeds 80%, the rolling stops and the uneven thickness ratio increases. You can see that it is increasing.

Therefore, the material 20 is used as the shaft member 1
When the outer diameter reduction rate B when rolling to 0 exceeds 50% or the cross-sectional reduction rate C of the hollow portion exceeds 80%, the outer diameter reduction rate B and the cross-sectional reduction rate C within the range not exceeding these
It is better to carry out rolling multiple times.

In the rolling method using this 3-roll type inclined rolling mill, the roll position R of the roll 1 is rolled during the rolling of the material 20.
By changing g at the boundary between the solid portion 20b and the hollow portion 20a, it is possible to manufacture the shaft member 10 in which the outer diameter OD ₁ is different between the hollow portion 10a and the solid portion 10b. That is, when the solid portion 10b has a margin in strength, the solid portion 10b has a small diameter, and when the hollow portion 20a has a margin in strength, the hollow portion 10a has a small diameter to further reduce the weight. .

Although the cone type roll 1 is used in the above description, the barrel type (barrel type) roll 1 has a roll diameter that decreases from the gorge portion 1a toward both the inlet and outlet sides. May be used.

Further, as the tilt rolling mill, the three-roll type tilt rolling mill in which the three rolls 1 are provided around the pass line X has been described, but four rolls 1 are provided around the pass line X. A 4-roll type inclined rolling mill may be adopted. However, an inclined rolling mill having five or more rolls 1 has a complicated structure and is not practical. On the other hand, in an inclined rolling mill having two rolls 1, an internal defect is likely to occur in the solid portion 10b of the rolled shaft member 10 due to the so-called Mannesmann effect during rolling of the solid portion 20b, Further, the guides provided at positions different by 90 degrees around the pass line X with respect to the two rolls 1 may cause seizure flaws. Therefore, a 3-roll type or 4-roll type inclined rolling mill is used.

Rolling Method Using Hole Rolls This method is a method in which the material 20 is rolled onto the shaft member 10 by a pair of hole rolls that are vertically opposed to each other with a pass line in between.

That is, instead of the three cone-shaped rolls provided around the pass line described with reference to FIGS. 3 to 5, the rolls are vertically opposed to each other with the pass line interposed therebetween.
A rolling mill equipped with a pair of hole rolls is used. This hole-type roll has a structure in which a plurality of hole-types having different sizes are provided in the axial direction thereof, and the hole-type roll is rotationally driven and the space between the upper and lower rolls can be adjusted.

Material 2 shown in FIG. 2 is produced by such a rolling mill.
When 0 is rolled into the shaft member 10 shown in FIG. 1, the outer diameter OD ₂ of the material 20 to the outer diameter OD of the shaft member 10
Set a roll with multiple pore types between ₁ and
The upper and lower roll intervals are adjusted, and the shaft member 10
A mandrel bar having an outer diameter dm corresponding to the inner diameter ID ₁ of the hollow portion 10a is connected to the thrust block. Then, the solid portion 20b of the raw material 20 heated to a predetermined temperature is set to the rolling front side, the thrust block is advanced to insert the mandrel bar into the hollow portion 20a of the raw material 20, and the raw material 20 is further advanced.

The end of the material 20 is bitten into one of a plurality of hole types provided on the roll, and thereafter, the material 20 is advanced by rotation of the roll, and the diameter is reduced in order from the solid portion 20b. To be done. During this time, the thrust block is also advanced, and the mandrel bar is advanced together with the material 20. 1
When the diameter reduction processing with one hole die is completed, the material 20 is retracted together with the mandrel bar, and the material 20, the mandrel bar and the thrust block are laterally moved to a portion of the hole die having a smaller diameter than the above hole die, The material 20 is rolled by the mold. Repeat this.

During the repeated rolling, the solid portion 20b and the hollow portion 20a are reduced in diameter, and after the inner surface of the hollow portion 20a contacts the mandrel bar, the hollow portion 20a is thinned. When rolling to the predetermined outer diameter is completed,
The mandrel bar is pulled out from the hollow portion 10a of the shaft member 10.

Method of drawing or pushing out with a die This method uses a die provided on the pass line to
This is a method of drawing the material 20 into the shaft member 10.

That is, one die is provided on the pass line instead of the three cone type rolls provided around the pass line described with reference to FIGS. 3 to 5, and
A drawing device equipped with a chuck that moves along the pass line on the exit side of the die is used.

When the material 20 shown in FIG. 2 is drawn into the shaft member 10 shown in FIG. 1 by such a drawing device, a die having an inner diameter corresponding to the outer diameter OD ₁ of the shaft member 10 and a shaft are used. Hollow part 10a of the member 10
The mandrel bar having the outer diameter dm corresponding to the inner diameter ID ₁ of ₁ is set in the drawing device. After that, the solid portion 20b of the material 20 having the lubricating coating formed on the inner and outer surfaces is pulled out to the leading end side, and the thrust block is advanced to insert the mandrel bar into the hollow portion 20a of the material 20. Then, after the tip of the mandrel bar reaches the bottom of the hollow portion 20a, the thrust block is further advanced to push the material 20 into the die, and the tip of the solid portion 20b is projected to the exit side of the die to form a grip portion. To do. After that, the gripping portion is gripped by a chuck, and the material 20 is pulled out from the die by the chuck.

During drawing, the thrust block may be advanced to advance the mandrel bar according to the advance speed of the material 20 being rolled, or it may be stopped. When stopping, it is preferable to use an inner surface restricting tool having a plug 2b at the tip of the supporting rod 2a having the same structure as that in FIG.

As a result, the solid portion 20b is reduced in diameter, and the hollow portion 20a is reduced in diameter and reduced in thickness. When the drawing process is completed, attach the mandrel bar to the shaft member 1.
0 from the hollow portion 10a.

In this drawing method, when the workability (outer diameter reduction rate B and hollow section reduction rate C) required to form the material 20 into the shaft member 10 is small,
It may be performed once, and may be performed a plurality of times when the required degree of processing is large. The upper limits of the outer diameter reduction rate B and the cross-section reduction rate C of the hollow portion during the drawing process are determined by the strength of the material 20, the drawing force of the apparatus, the lubrication coefficient between the material 20 and the die, and the like.

In the above description, the lubricating film is formed in advance on the inner and outer surfaces of the material 20, but, for example, lubricating oil may be supplied to the die and the mandrel bar during the drawing process. Also,
The material 20 was pushed into the die to form the grip,
A grip portion having a diameter smaller than the bearing diameter of the die may be formed in advance at the tip of the solid portion 20b of the material 20.

Further, the chuck which moves along the path line may be omitted, and the material 20 may be pushed out from the die by a thrust block through a mandrel bar. Punching Method by Roll This method is a method of punching the material 20 into the shaft member 10 by using a plurality of hole-shaped rolls provided in series on the pass line.

That is, instead of the three cone type rolls provided around the pass line described with reference to FIGS. 3 to 5, a pair of hole type rolls facing each other with the pass line interposed therebetween are provided along the pass line. A punching device having a plurality of structures is used. The plurality of hole type rolls have smaller hole type diameters on the downstream side of the pass line and are not driven to rotate.

When the material 20 shown in FIG. 2 is punched into the shaft member 10 shown in FIG. 1 by such a punching device, the shaft member 10 is cut from the outer diameter OD ₂ of the material 20.
Outer diameter OD ₁ of a plurality of diameter rolls is set to adjust the upper and lower roll intervals, and the outer diameter dm corresponding to the inner diameter ID ₁ of the hollow portion 10 a of the shaft member 10.
Connect the mandrel bar of to the thrust block. Then, the solid portion 20b of the material 20 is set to the rolling front side, and the thrust block is advanced to move the mandrel bar to the material 20.
It is inserted in the hollow portion 20a of the. Then, after the tip of the mandrel bar reaches the bottom of the hollow portion 20a, the thrust block is further advanced to push the material 10 through a plurality of hole-shaped rolls. As a result, the solid portion 20b is reduced in diameter, and the hollow portion 20a is reduced in diameter and reduced in thickness.

When the punching is completed, the mandrel bar is pulled out from the hollow portion 10a of the shaft member 10. In addition,
Also in this case, the punching process may be performed plural times.

Among the methods (1) to (4) described above, in the rolling method using the inclined roll, since the material 20 is thinned by the roll 1 and the mandrel bar 2 while rotating around the axis, the material 20 is manufactured. There is an effect that uneven thickness generated at the time of is corrected. Therefore, the rolling method using the inclined roll is preferable for the diameter reduction processing in the present invention. However, the method of ~ may be used, or another method of reducing the diameter may be used.

The above description is for the case where the hollow portion 20a of the material 20 is subjected to the diameter reduction processing accompanied by the thickness reduction processing, and the solid portion 20b is subjected to the diameter reduction processing. However, there are cases where it is not necessary to reduce the diameter of the solid portion 20b.

That is, the outer diameter of the solid portion 10b is the hollow portion 1
This is a case where a shaft member having an outer diameter larger than 0a is manufactured. In this case, the material 20 shown in FIG. 2 having the same length as the outer diameter of the solid portion 10b of the shaft member may be used, and only the hollow portion of the material 20 may be subjected to the diameter reduction process accompanied by the thickness reduction process. In this case, using the above-mentioned or a device provided with a roll whose interval can be adjusted, after the solid part 20b passes, the roll interval is adjusted to a predetermined interval to reduce the diameter of the hollow part 20a. Give. Even when manufacturing the shaft member of FIG. 1 in which the outer diameter of the hollow portion 10a and the outer diameter of the solid portion 10b are the same, the outer diameter of the solid portion 20b is the same as that of the solid portion 10b of the shaft member. When a material having an outer diameter equal to the outer diameter and an outer diameter of the hollow portion 20a larger than this is used, only the hollow portion 20a of the material 20 may be subjected to a diameter reduction process accompanied by a thickness reduction process. In this case, the above methods (1) to (4) can be adopted.

[0080]

EXAMPLE 1 A shaft member 10 was formed into 5 by a rolling method using a 3-roll type inclined rolling mill shown in FIGS.
0 pieces were manufactured. Table 3 shows the conditions of the material 20, the rolling conditions, and the dimensions of the shaft member.

[0081]

[Table 3]

Then, the hollow portion 10a is rolled 40 mm from the end of the hollow portion 10a of the shaft member 10.
The uneven thickness ratio up to the middle position was investigated.

As a comparative example, 50 solid materials made of JIS S45C having an outer diameter of 30 mm and a length of 850 mm were prepared, and a hollow portion having a length of 540 mm was formed by a drill having a diameter of 20 mm and a length of 1000 mm. As a shaft member, the uneven thickness ratio was investigated in the same manner as above.

As a result, the rate of occurrence of the shaft member having a wall thickness deviation of more than 5% was 0% in the present invention example, whereas it was 12% in the comparative example.

Example 2 Fifty shaft members 10 were manufactured by a rolling method using a 3-roll type inclined rolling mill shown in FIGS. 3 to 5. Table 4 shows the conditions of the material 20, the rolling conditions, and the dimensions of the shaft member.

[0086]

[Table 4]

Thereafter, the hollow portion 10a is rolled from a position 40 mm from the end of the hollow portion 10a of the shaft member 10 which is rolled.
The uneven thickness ratio up to the middle position was investigated.

As a comparative example, 50 solid materials made of JIS S45C having an outer diameter of 30 mm and a length of 1455 mm are used.
This preparation was performed, and a hollow portion having a length of 920 mm was formed with a drill having a diameter of 20 mm and a length of 1200 mm to form a shaft member, and the uneven thickness ratio was investigated in the same manner as described above.

As a result, the rate of occurrence of the shaft member having a wall thickness deviation of more than 5% was 4% in the present invention example, while it was 30% in the comparative example.

Example 3 Fifty shaft members 10 were manufactured by a rolling method using a three-roll tilt rolling mill shown in FIGS. 3 to 5. Table 5 shows the conditions of the raw material 20, the rolling conditions, and the dimensions of the shaft member.

[0091]

[Table 5]

Thereafter, the hollow portion 10a is rolled from a position 40 mm from the end of the hollow portion 10a of the shaft member 10 rolled.
The uneven thickness ratio up to the middle position was investigated.

As a comparative example, 50 solid materials made of JIS S45C having an outer diameter of 30 mm and a length of 830 mm were prepared, and a hollow portion having a length of 500 mm was formed by a drill having a diameter of 24 mm and a length of 1200 mm. As a shaft member, the uneven thickness ratio was investigated in the same manner as above.

As a result, the rate of occurrence of the shaft member having a thickness deviation ratio of more than 5% was 0% in the inventive example, whereas it was 10% in the comparative example.

[0095]

According to the method of the present invention, a hollow member having a solid portion on one end side can be manufactured with a small uneven thickness and a high yield. Therefore, it is particularly suitable for manufacturing a shaft member having a small diameter.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an example of the shape of a shaft member manufactured by the method of the present invention.

FIG. 2 is a partial cross-sectional side view showing the shape of a material used in the present invention.

FIG. 3 is a schematic view for explaining a state of rolling by a 3-roll type inclined rolling mill, and is a front view seen from the entrance side of the inclined rolling mill.

FIG. 4 is a sectional view taken along the line AA in FIG.

FIG. 5 is a view on arrow EE of FIG.

FIG. 6 is a side view showing another example of the inner surface regulation tool.

[Explanation of symbols] 1: roll, 2: Mandrel bar (inner surface control tool), 3: Thrust block, 10: shaft member, 10a: hollow part, 10b: solid part, 20: Material, 20a: hollow part, 20b: Solid part.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B21D 53/88 B21D 53/88 Z (72) Inventor Kazushi Shimoda 4 Kitahama, Chuo-ku, Osaka-shi, Osaka 5th to 33rd Sumitomo Metal Industries, Ltd. F term (reference) 3J033 AA01 AB03 AC01 BA01 BA07 4E028 EA07

Claims (3)

[Claims] 1. An inner surface restricting tool is inserted into the hollow portion of a material having a solid portion on one end side in the axial direction of the hollow portion, and at least the hollow portion is subjected to diameter reduction processing accompanied by wall thinning processing. A method of manufacturing a hollow member having a solid portion on one end side thereof. 2. The hollow having a solid portion on one end side according to claim 1, wherein the processing is carried out hot by an inclined rolling mill provided with three or four rolls around a pass line. A method of manufacturing a member. 3. The above-mentioned processing is carried out by using an inclined rolling mill having three rolls provided around a pass line so that an outer diameter reduction ratio B defined by the following formula (1) is 50% or less and the following (2) The method for manufacturing a hollow member having a solid portion on one end side according to claim 2, wherein the cross-sectional reduction rate C of the hollow portion defined by the formula is 80% or less. _{B (%) = 100 · (} OD 2 -OD 1) / OD 2 ··· (1) C (%) = 100 · (A 2 -A 1) / A 2 ··· (2) where, A ₂ = (OD ₂ ² −ID ₂ ² ) A ₁ = (OD ₁ ² −ID ₁ ² ) where OD _{2 is} the outer diameter of the material (mm) OD _{1 is} the outer diameter after processing (mm) ID _{2 is the} material Inside diameter (mm) ID ₁ : Inside diameter after processing (mm)