JPH0117769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cylindrical member, and more particularly to a method for manufacturing a cylindrical member that can significantly improve the accuracy of the cylindrical member.

Conventionally, the cylindrical member has been a so-called butt-type cylindrical member in which a rectangular plate-shaped material is curved and its ends are butted together, or a rectangular plate-shaped material is curved and formed at each end thereof. A so-called clinch type cylindrical member in which a concave portion and a convex portion are engaged with each other is known.

As a means for improving the roundness and wall thickness accuracy of this type of cylindrical member, it is possible to improve the roundness and wall thickness accuracy of this type of cylindrical member by using a shaft core disposed within the cylindrical member and a holder disposed on the outer surface side of the cylindrical member. Examples include a so-called sizing method in which a cylindrical member is compressed in the radial direction, and a so-called lateral pressure method in which a compressive force is applied to the cylindrical member from both ends in the axial direction. Furthermore, as a means to further improve the precision of the cylindrical member, it has been proposed that the cylindrical member formed by the above-mentioned sizing method is further formed by a lateral pressure method in the next step.

However, manufacturing a cylindrical member through a process using the sizing method and a process using the lateral pressure method in this way, although it is possible to improve the accuracy of the cylindrical member to a certain extent, has traditionally been difficult to do with sizing. The lateral pressure process is a separate process, which makes manufacturing difficult, and since forces act on the cylindrical member from different directions in each process, the distortion of the cylindrical member corrected in the previous process can be transferred to the next process. However, there were problems such as reoccurrence, and sufficient accuracy could not always be expected.

The present invention has been made to solve these conventional difficulties, and its purpose is to provide a method for manufacturing a cylindrical member that can improve the roundness and wall thickness accuracy of the cylindrical member. It is in.

The present invention is characterized by focusing on the fact that the conventional drawback is that the sizing process and the lateral pressure process are separate processes, and the two processes are performed almost simultaneously.

More specifically, a rectangular plate material is curved to form a butt or clinch type cylindrical member, and then this cylindrical member is formed into a cylindrical member having a wall thickness smaller than that of the cylindrical member and a cylindrical member of the holder. The inner diameter of the shaped bore and the outer diameter of the cylindrical member, or the outer diameter of the cylindrical shaft core and the inner diameter of the cylindrical member are set to be the same, and the diameter is plastically deformed while being inserted into the gap in the bore. While applying a pressing force in the direction, the inner circumference and outer circumference of the cylindrical member are simultaneously restrained, and further, while maintaining this radial pressing force, plastic deformation occurs in the axial direction at the end of the process of applying the radial pressing force. Compressive forces are applied together, and the axial compressive force and radial pressing force impart desired roundness and straightness to the cylindrical member.

Hereinafter, one embodiment of the present invention will be described using a butt type cylindrical member as an example.

First, Figure 1 shows a butt-type cylindrical member 1.
As is conventionally known, this cylindrical member 1 is formed by curving a rectangular plate-shaped material and abutting both ends thereof against each other. This cylindrical member 1 is given the required dimensional accuracy by the device shown in FIG. 2, and its configuration is as follows. That is, as is clear from FIG. 2, this device includes a die 2 provided with a bore 3 into which a cylindrical member 1 is inserted, and a core 5 protruding from the tip to be inserted into the cylindrical member 1. a punch 4 that is pushed into the inside of the punch 3 with a force P shown in the figure; a knockout punch 6 that faces the punch 4 and receives the cylindrical member 1;
It further comprises a base 7 that supports the die 2, the diameter D1 of the bore ₃ provided in the die 2 is formed to be the same as the outer diameter _D3 of the cylindrical member 1 before processing, and a punch 4. The diameter D ₂ of the core 5 is larger than the inner diameter D ₄ of the cylindrical member 1 before processing.
In other words, the gap between the die 2 and the core 5 is set smaller than the wall thickness of the cylindrical member 1 before processing.
If the cylindrical member 1 is attached to the core 5 of the punch 4 and press-fitted into the bore 3 of the die 2, a radial force will be applied to the cylindrical member 1, and the final Sometimes, the punch 4 and the knock-out punch 6 are used to clamp and apply compressive force in the axial direction at the same time. The bore 3 and the core 5 are formed with high roundness accuracy that matches the planned finishing dimensions of the inner and outer diameters of the cylindrical member.

Therefore, to explain the manufacturing method of the cylindrical member 1 using the above-mentioned apparatus, in manufacturing, prior to the above-mentioned precision imparting processing, a rectangular plate-shaped material is first curved and both ends of the material are butted against each other to form the cylindrical member 1. do.

Next, this cylindrical member 1 is inserted into the core 5 of the punch 4.
This cylindrical member 1 is press-fitted into the bore 3 of the die 2 with a force of P as shown in the figure. In such a case, the diameter D ₂ of the core 5 is the same as the diameter D 2 of the cylindrical member 1 before processing.
Since it is formed to have a larger diameter than the inner diameter D ₄ of the cylindrical member 1 , a force in the direction of diameter expansion is applied to the cylindrical member 1 when the core 5 is press-fitted. At the same time, when the punch 4 is inserted, the cylindrical member 1 is pressed from both sides in the axial direction by the punch 4 and the knockout punch 6, so that a compressive force in the axial direction is applied to the cylindrical member 1. be done. Therefore, due to the pressing force in the diameter expanding direction and the compressive force in the axial direction, which are applied almost simultaneously,
The cylindrical member 1 is strongly pressed against the inner circumferential surface of the bore 3 and the outer circumferential surface of the core 5, which have been manufactured in advance with a high degree of circularity, thereby providing extremely high degree of circularity and wall thickness accuracy. It happens.

This is clear from the following experimental results.
That is, the applicant has determined that the diameter D ₁ of the bore 3 is 49.65φ.
A machining experiment was carried out on a cylindrical member 1 with an outer diameter D ₃ of 49.65 φ mm before machining using a die 2 with a diameter D ₂ of 44.88 φ mm and a punch 4 with a core 5 having a diameter D 2 of 44.88 φ mm. 10~30μm, wall thickness variation 0.02~0.04
mm, and back straightness values of 10 to 30 μm could be obtained.

Note that the relationship between the diameter D ₁ of the bore 3 and the outer diameter D ₃ of the cylindrical member before processing does not necessarily have to be exactly the same, but may be within the standard for roundness, wall thickness variation, and straightness. If you do so, you can achieve the desired effect.

Normally, the standard for this type of cylindrical member is that the outer diameter roundness is 150 μm or less and the wall thickness variation is 0.15 mm or less, so the above experimental results confirm that the method of the present invention can achieve sufficiently good accuracy. can.

In the embodiments and processing experiments described above, the diameter D ₂ of the core 5 of the punch 4 is made larger than the inner diameter D ₄ of the cylindrical member 1 before processing, and a force in the diametrical direction is applied to the cylindrical member 1. In the above explanation, the diameter D ₂ of the core 5 is the same as the inner diameter D ₄ of the cylindrical member 1 before processing, and the diameter D 1 of the bore 3 of the die 2 is the same as the diameter D 4 of the cylindrical member ₁ before processing. Outer diameter of member 1 D ₃
Even if the cylindrical member 1 is made to have a smaller diameter and a force is applied in the direction of diameter reduction, the same effect as in the above embodiment can be expected.

As explained above, in the first embodiment of the present invention, a butt-type cylindrical member is formed by curving a rectangular plate-like material, and then a shaft core is inserted into this cylindrical member, and the cylindrical member is The shaped member is placed in the bore of the holder, and the inner diameter of the bore and the outer diameter of the cylindrical member are set to be the same, or the outer diameter of the shaft core and the inner diameter of the cylindrical member are set to be the same and the gap between the bore and the shaft core is set as above. By making it smaller than the wall thickness of the cylindrical member,
First, a radial pressing force that causes plastic deformation is applied to this cylindrical member, and while this radial pressing force is maintained, a compressive force that causes plastic deformation in the axial direction is applied at the end of the process of applying the radial pressing force. Since the cylindrical member is applied with a radial pressing force at the beginning of processing, the undulations of the inner and outer surfaces that occur during the cylinder forming process are corrected, and the undulations of the inner and outer surfaces that occur during the cylinder forming process are corrected, and The applied axial compressive force achieves a process of conforming the inner and outer surfaces to the bore and the shaft core surface, and the strain in each part is dispersed and absorbed between them. In other words, according to this invention, the conventional sizing process and the lateral pressure process are performed at the same time, and compared to the conventional method in which both processes were performed separately, both processes are performed almost simultaneously. Due to the synergistic effect, the generated strain can be complemented with each other, and the roundness and wall thickness accuracy of the cylindrical member can be significantly improved. Therefore, it is clear that when this cylindrical member is used as a bearing, abnormal heat generation and seizure can be effectively eliminated.

Next, another embodiment of the present invention will be described using a clinch type cylindrical member as an example.

FIG. 3 shows a clinch type cylindrical member 11, which is a generally rectangular plate-like material having a concave portion 11a and a convex portion 11b at both ends, as is conventionally known. The concave portion 11a and the convex portion 11b are engaged with each other to connect and connect the abutting portions. This cylindrical member 11 is given the required dimensional accuracy by the device shown in FIG.
As is clear from the illustrated embodiment, this device has basically the same structure as the device used for the butt-type cylindrical member 1.

That is, this device, as shown in FIG.
A die 12 is provided with a bore 13 into which the cylindrical member 11 is inserted, and a punch 14 is provided with a protruding core 15 at its tip to be inserted into the cylindrical member 11 and is pushed into the bore 13 with a force of _P1 as shown in the figure. , a knockout punch 16 that faces the punch 14 and receives the lower end side of the cylindrical member 11, and a base 17 that supports the die 12. With these configurations, it is possible to simultaneously apply compressive force in the axial direction and force in the radial direction to the cylindrical member 11, similar to the embodiment shown in FIG. 3 above. However, unlike the device used for the butt-type cylindrical member 1 described above, this device
1 is unique in that it applies a force in the diameter-reducing direction instead of applying a force in the diameter-increasing direction.

That is, the diameter D ₁₁ of the bore 13 of the die 12 is smaller than the outer diameter D 13 of the cylindrical member 11 before processing, while the diameter D ₁₂ of the core 15 of the punch 14 is smaller than the outer diameter D ₁₃ of the cylindrical member 11 before processing.
is formed to have the same diameter as the inner diameter _D14 of the cylindrical member 11 before processing.

Therefore, a force is applied to the cylindrical member 11 in the direction of diameter reduction by the die 12 and the punch 14, and a compressive force in the axial direction is applied by the punch 14 and the knockout punch 16 simultaneously with the diameter reduction force. It will be added.

Note that the reason why the force in the diametrical direction is applied to the cylindrical member 11 instead of the force in the diametrical expanding direction is that when a force in the radial expanding direction is applied to the clinch type cylindrical member 11, the clinch portion, That is, this is because an undesirable separation phenomenon occurs at the engagement portion between the recess 11a and the protrusion 11b.

Next, the method for manufacturing this clinch type cylindrical member 11 will be explained. Similar to the above-mentioned butt type, when manufacturing, first, a rectangular plate-shaped material is curved, and the recesses 11a at both ends of the cylindrical member 11 are The convex portions 11b are engaged with each other to form the cylindrical member 11 shown in FIG. 3.

Next, the core 15 of the punch 14 is inserted into the cylindrical member 11, and in this state, the cylindrical member 11 and the punch 14 are pressed into the bore 13 of the die 12 with a force of _P1 as shown in the figure. Since D ₁₁ is formed to have a smaller diameter than the outer diameter D ₃ of the cylindrical member 11 before machining, compressive force is applied to the cylindrical member 11 in the diameter reduction direction by the press-fitting operation into the bore 13, and this At the same time, by pressing the cylindrical member 11 into the bore 13, the cylindrical member 11 is inserted into the punch 14.
The cylindrical member 11 is clamped from both sides in the axial direction between the cylindrical member 11 and the knockout punch 16, and a compressive force in the axial direction is simultaneously applied to the cylindrical member 11. Thus, due to the synergistic effect of the compressive force in the diametrical direction and the compressive force in the axial direction, the cylindrical member 11 is compressed by the bore 13 and the core 15 with high dimensional accuracy, and has extremely excellent roundness and It is possible to provide wall thickness accuracy.

The experimental results shown in FIG. 5, FIG. 6, and _FIG .
Using a punch 14 with a core 15 having a diameter D ₁₂ of 44.82φ,
Diameter of bore 13 when outer diameter D ₁₃ before processing is set as 1
A machining experiment was carried out on a cylindrical member 11 having an outer diameter D ₁₃ where D ₁₁ corresponds to 0.997. Fifth
The experimental results shown in Figs. Changes in outer diameter straightness, back surface straightness, and wall thickness variations were measured when the axial length of the cylindrical member was changed. The four types of symbols shown in FIG. 8 each indicate the wall thickness at the measurement location shown in FIG. 7.

As understood from the above experimental results, good accuracy can be obtained by setting the side pressure ratio to 2% or more, preferably about 3% to 8%. Regarding compression in the direction of diameter reduction, when the outer diameter of the cylindrical member before compression is 1, good results can be obtained when the outer diameter after compression is 0.950 to 0.997. has been confirmed.

As explained above, in the second embodiment of the present invention, a compressive force in the radial direction is first applied to the cylindrical member, and at the end of the additional stroke of the radial compressive force, the axial compressive force is cooperated. Since the compressive force in the diameter reduction direction is applied to the cylindrical member at the initial stage of processing, the waviness of the inner and outer surfaces and the biasing of the clinch portion that occur during the cylinder forming process are corrected, and the tension is also reduced. Subsequently, the axial compressive force applied in cooperation achieves a process of conforming to the inner and outer surfaces of the bore and the shaft core surface, and the strain of each part is mutually dispersed and absorbed between these. In other words, according to this second embodiment, the conventional sizing process and the lateral pressure process are performed simultaneously and in parallel, and compared to the conventional method in which both processes were performed separately, almost Due to the synergistic effect of both processes performed simultaneously, the generated strains are complemented with each other, and the roundness and wall thickness accuracy of the cylindrical member can be significantly improved. In particular, since a force is applied to the cylindrical member in the direction of diameter reduction for sizing, there is no risk of separation occurring at the clinch portion of the cylindrical member, making it extremely suitable for manufacturing clinch-type cylindrical members. be able to.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a butt type cylindrical member, FIG. 2 is a sectional view showing an example of a device for processing this cylindrical member, and FIG. 3 is a perspective view showing a clinch type cylindrical member. Fig. 4 is a cross-sectional view showing an example of a device for processing this cylindrical member, and Figs. 5, 6, and 8 show the outer diameter roundness and back roundness when changing the side pressure ratio, respectively. FIG. 7 is a diagram showing the measurement positions in the experiment shown in FIG. 8. 1, 11... Cylindrical member, 2, 12... Dice,
3,13...Bore, 4,14...Punch, 5,15...
Core, 6, 16...knockout punch, 11a...
Concave portion, 11b... Convex portion.

Claims (1)

[Claims] 1. A rectangular plate-shaped material is curved to form a butt or clinch type cylindrical member, and then this cylindrical member is formed into a material having a wall thickness smaller than that of the cylindrical member and of a holder. The inner diameter of the cylindrical bore and the outer diameter of the cylindrical member, or the outer diameter of the cylindrical shaft core and the inner diameter of the cylindrical member are set to be the same, and plastic deformation occurs while being inserted into the gap in the shaft core and the bore. While applying a radial pressing force, the inner circumference and outer periphery of the cylindrical member are simultaneously constrained, and further, while maintaining this radial pressing force, plastic deformation is caused in the axial direction at the end of the process of applying the radial pressing force. A method for producing a cylindrical member, characterized in that the axial compressive force and the radial pressing force are used to impart desired roundness and straightness to the cylindrical member. 2 When the axial length of the cylindrical member before compression is l and the axial length after compression is l', the lateral pressure ratio of the cylindrical member given by (l-l')/l x 100 is 3. The manufacturing method according to claim 1, characterized in that the content is 8% to 8%. 3. Claims characterized in that the cylindrical member is compressed so that the wall thickness after compression is 0.950 to 0.997, assuming that the wall thickness of the cylindrical member before being compressed in the diameter reduction direction is 1. The manufacturing method according to item 1 or 2.