JPH0310417B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a seamless thin-walled steel endless belt with high precision and uniform wall thickness.

(Prior art) Conventionally, thin-walled steel endless belts are formed by making a metal plate formed into a belt shape, polymerizing or butt welding it at both ends in the longitudinal direction to make it endless, and then polishing and deburring it. are doing.

However, since the thin-walled steel endless belt formed by this method is polymerized or butt welded at both ends in the longitudinal direction, the metallographic structure changes in the welded part and differs from other parts. It becomes a cast structure and forms a weak part.

In addition, thin-walled steel endless belts, especially thin-walled steel endless belts installed between the pulleys of continuously variable transmissions for vehicles, have a very large torque transmitted from the prime mover and a high rotational speed. The tension applied to the endless belt is very large.

Furthermore, in continuously variable transmissions, continuously variable speed is achieved by changing the effective radius of the pulley, so the curvature of the thin steel endless belt when wound around the pulley may become extremely small. . In this case, an alternating load with a large amplitude is applied to the thin steel endless belt by repeating a state of large curvature and a state of small curvature.

In the steel thin-walled endless belt formed by the above method, if there is a weak part such as a welded part, it may break or break at that part. A method of manufacturing a thin-wall steel endless belt with eliminated sections is provided.

According to this method, a thin metal plate is explosively formed,
After applying pressure to the center by drawing or the like to form a container shape, the container-shaped molded product is cut into rings perpendicular to the axis.

The edges of the ring-cut material are polished and deburred to form an endless belt material, and the endless belt material is then rolled to a predetermined size. At this time, the weakness inherent in the structure of the endless belt material is simultaneously removed by the rolling process (see Japanese Patent Publication No. 49-23476).

(Problems to be Solved by the Invention) However, in the steel thin-walled endless belt with the above structure, the inherent weakness in the structure can be eliminated, but the stress generated by cutting the container-shaped molded body into rings Therefore, it is not possible to remove the tissue changes remaining on both edges of the endless belt material.

That is, when cutting a container-shaped molded body into rings, the stress applied by the cutting blade is quite large because the container-shaped molded body is relatively thick.
Therefore, it is difficult to remove the structural change that occurs at both edges of the endless belt material by rolling, and the portion where the structural change has occurred extends circumferentially and remains due to rolling. .

Therefore, the present invention has high dimensional accuracy in overall circumference length, wall thickness, and width, can be manufactured efficiently and at low cost, and can eliminate the fragility that occurs in the endless belt material due to structural changes caused by processing. An object of the present invention is to provide a method for manufacturing a thin steel endless belt that can increase reliability in terms of strength and toughness.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention press-forms a thin steel sheet metal to form a molded body 3 having a cylindrical surface, and the molded body 3 is orthogonally disposed about the axis of the molded body 3. The rough section 4 of the seamless thin-walled steel endless belt 10 is produced by cutting along the plane.

Next, a pair of rolling rolls 6 having a width C slightly narrower than the width B of the rough shape material 4 are used to roll the rough shape material 4 with non-rolling portions remaining on both edges, The overall circumferential length and plate thickness of the width of the rolling roll 6 are adjusted to predetermined dimensions.

Then, both edges of the adjusted and processed belt 9 are separated by a width cutting process to obtain a width with a highly accurate dimension.

(Function and effects of the invention) Steel thin endless belt 10 of the present invention
The manufacturing method is to produce a width C that is slightly narrower than the width B of the rough section 4.
With the rolling rolls 6, the thickness of the rough shaped material 4 is reduced to a predetermined thickness at the width of the rolling roll 6, while leaving non-rolling parts on both edges of the rough shaped material 4. Since rolling processing is performed so that the rough shape material is not rolled, the non-rolling processing portion of the rough section acts as a resistance, and the amount of change in the total circumference length is reduced.

Therefore, compared to the case where the entire rough section 4 is subjected to rolling processing, the entire circumference length can be easily managed.

Furthermore, since the amount of change in the overall circumferential length can be reduced during rolling processing, elongation in the width direction is promoted. As a result, the tissue change caused by the cutting blade when cutting the container-shaped molded body into rings is pushed out in the width direction and is rejected from the rolling portion.

Then, by the width cutting process after the rolling process, both edges of the processed belt 9 are separated, and a thin steel endless belt 10 from which the tissue-changed portion has been completely removed can be obtained.

Although a structure change occurs at both ends of the steel thin endless belt 10 due to the width cutting process, the amount of the structure change is extremely small and does not affect the brittleness of the steel thin endless belt 10. That is, since the width cutting process is performed after the rolling process, the plate thickness of the width cutting process part is thin, and the necessary processing time is shortened. Therefore, the amount of heat generated during processing is small, and the structural changes that occur are extremely small.

Moreover, the structure change that occurs at both ends of the steel thin endless belt 10 by the width cutting process becomes uniform in the circumferential direction. In other words, at the time when a press-formed body is formed by press working, the thickness of the press-formed body is not uniform in the circumferential direction, and when the press-formed body is cut into rings, the resulting structural changes are uniform in the circumferential direction. instead, it increases vulnerability. On the other hand, when performing the width cutting process after the above-mentioned rolling process, the rolling process has already been performed and the entire plate thickness is homogeneous with an accuracy of ±0.005mm, so even if a structural change occurs, it will be homogeneous in the circumferential direction. The steel thin endless belt 10 does not become brittle.

In the above description, each element is given a reference numeral for convenience of explanation, but these do not limit the configuration of the present invention.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a perspective view of a disc-shaped blank in the method of manufacturing a thin steel endless belt of the present invention, Fig. 2 is a diagram of the state of press processing of the disc-shaped blank, and Fig. 3 is a perspective view of a press-formed product. , FIG. 4 is a perspective view of a rough profile obtained by ring-cutting a press-formed body, FIG. 5 is an explanatory diagram of the process of rolling processing, FIG. 6 is a sectional view of the endless belt after rolling processing, and FIG. The figure is a perspective view of the endless belt after width cutting processing.

First, as shown in FIG. 1, a thin steel sheet metal is punched out to form a disc-shaped blank 1, and the blank 1 is pressed as shown in FIG. The steel sheet metal is tempered to HRC30 or less before punching the blank 1, and it becomes possible to use a strong, high-tensile steel thin sheet metal that is difficult to press form as the material.

In Fig. 2, 2 is a press, 21 is a die, 2
2 is a cylindrical hole of a predetermined diameter formed in the die 21, and 23 is a holding plate 23 which holds the blank 1 between it and the die 21. A cylindrical punch 24 having a predetermined diameter is pushed into the cylindrical hole 22 to squeeze the blank 1 to a predetermined depth.

The cylindrical surface 3 as shown in Fig. 3 is obtained by deep drawing.
A press molded body 3 having A is formed. Subsequently, the molded body 3 is cut into a predetermined width B along a plane perpendicular to the central axis using a machine such as a lathe, to produce a rough-shaped steel thin-walled endless belt material 4 as shown in FIG. be done. The rough shaped material 4 has a width of B,
It is composed of an annular body with a thickness of E.

Next, the rough shaped material 4 manufactured in this way is
Rolling processing is performed by a rolling processing machine 8, an example of which is shown in FIG.

In the figure, 5 is the distance l between axes arranged in parallel.
A rough profile 4 (FIG. 4) is installed between the pulleys 5. A pair of rolling rolls 6 are arranged between the pair of pulleys 5 so as to sandwich the rough shaped material 4, and have a width C slightly narrower than the width B of the rough shaped material 4. Reference numeral 7 denotes a plate thickness measuring device for measuring the plate thickness of the rough section 4 during the rolling process.

In the rolling machine 8 having the above configuration, when the rolling roll 6 is rotated while controlling the distance l between the axes of the pair of pulleys 5, the rough section 4 is rolled and the thickness is increased as shown in FIG. The dimension E becomes a predetermined plate thickness dimension F at the width C of the rolling roll 6.

At this time, only a portion of the width C of the rolling roll 6 is rolled by the rolling roll 6, and the non-rolling portion of the rough section 4 serves as resistance to the rolling.

Therefore, the rough shaped material 4 does not extend in the circumferential direction, and the amount of change in the overall circumferential length is small, so the displaced flesh of the rough shaped material 4 is sent in the width direction, and the width of the rough shaped material 4 increases. is promoted. At this time, changes in the structure that occur on both edges of the rough shaped material 4 when cutting and forming the rough shaped material 4
It moves in the width direction of the rolling roll 6 and is pushed out from the width C portion of the rolling roll 6.

Next, both edges of the processed belt 9 obtained in the above steps are cut with a roll cutter (not shown) or the like to finish it to a predetermined width D as shown in FIG. Then, it is possible to manufacture a seamless, thin-walled steel endless belt 10 that has highly accurate overall circumferential length, plate thickness, and width, and is uniform in plate thickness.

Although a structure change occurs at both ends of the steel thin endless belt 10 due to the width cutting process, the amount of the structure change is extremely small and does not affect the brittleness of the steel thin endless belt 10. That is, since the width cutting process is performed after the rolling process, the plate thickness of the width cutting process part is thin, and the required processing time is shortened. Therefore, the amount of heat generated during processing is small, and the structural changes that occur are extremely small.

Moreover, the structure change that occurs at both ends of the steel thin endless belt 10 by the width cutting process becomes uniform in the circumferential direction. That is, at the time when the press-formed body 3 is formed by press working, the plate thickness of the press-formed body 3 is not uniform in the circumferential direction, and when the press-formed body 3 is cut into rings, the accompanying structural changes occur in the circumferential direction. It is not homogeneous in direction, which increases its fragility. On the other hand, when performing the width cutting process after the above-mentioned rolling process, the rolling process has already been performed and the entire plate thickness is homogeneous with an accuracy of ±0.005mm, so even if a structural change occurs, it will be homogeneous in the circumferential direction. The steel thin endless belt 10 does not become brittle.

Subsequently, the steel thin-walled endless belt 10 is quenched, and immediately following the quenching, it is tempered to homogenize the structure, resulting in a high-tensile steel thin-walled endless belt 10 with extremely superior tensile strength and toughness. can be manufactured.

In the method for manufacturing the steel thin endless belt 10 described above, the dimensions of the cylindrical surface 3A are precisely controlled when the press molded body 3 is shaped by press working, which is relatively easy to control dimensions. Therefore, the rough shaped material 4 with high dimensional accuracy in the entire circumferential length is produced, and then finely adjusted by rolling processing, so that the dimensional accuracy in the entire circumferential length of the steel thin endless belt 10 is extremely high.

In addition, the rolling process can ensure a plate thickness accuracy of ±0.005 mm, making the plate thickness dimension highly accurate and uniform.

And since there are no welds, it has excellent tensile strength.
Furthermore, since the manufacturing method does not require a welding machine or a finishing machine, capital investment can be significantly reduced.

Further, since the rolling roll 6 which is slightly narrower than the width of the rough shaped material 4 is used in the rolling process, the amount of change in the total circumferential length is reduced, making it easier to manage the total circumferential length during the rolling process.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a disc-shaped blank in the manufacturing method of a thin steel endless belt of the present invention, Fig. 2 is a diagram of the state of press processing of the disc-shaped blank, and Fig. 3 is a perspective view of a press-formed product. , FIG. 4 is a perspective view of a rough profile obtained by ring-cutting a press-formed body, FIG. 5 is an explanatory diagram of the process of rolling processing, FIG. 6 is a cross-sectional view of the endless belt after rolling processing, and FIG. The figure is a perspective view of the endless belt after the width cutting process. 1...Blank, 2...Press, 3...Press formed body, 4...Rough profile, 5...Pulley, 6...Rolling roll, 7...Plate thickness measuring device, 8...Rolling processing machine , 9... Belt after processing, 10... Steel thin endless belt, B... Width of rough profile material,
C...Width of rolled roll.

Claims (1)

[Claims] 1 Press-form a thin steel sheet metal to form a molded body with a cylindrical surface, cut the molded body on a plane perpendicular to the axis to make a rough shape for a seamless thin-walled steel endless belt, A pair of rolling rolls having a width slightly narrower than the width of the profile are used to roll the rough profile while leaving non-rolling parts on both edges, and the width of the rolling rolls is used to roll the entire circumference. A method for manufacturing a thin steel endless belt, which is characterized by adjusting the length and plate thickness to predetermined dimensions, and after the adjusted processing, cutting off both edges of the belt by width cutting processing to obtain a width of highly accurate dimensions.