JPH0593621U - Mandrel for forming recesses in hollow shafts - Google Patents

Abstract

(57) [Summary] [Purpose] A high-precision recess can be formed in the hollow shaft, and the split cored bar is removed after forming the recess to reduce the weight of the product. [Configuration] The hollow part of the hollow shaft A cylindrical core metal main body to be fitted is provided, and the core metal main body is divided in the radial direction to form a plurality of divided core metals, and a molding concave portion that is recessed in the axial direction in the outer peripheral portion of a predetermined divided core metal. Form.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a core metal for forming a recess in a hollow shaft, which is used when forming a recess that is recessed in the axial direction in a part of the hollow shaft in the longitudinal direction.

[0002]

[Prior Art]

 A cylindrical mandrel made of a single piece is formed of a relatively soft metal material, and the mandrel is closely fitted to a part of the hollow shaft in the longitudinal direction, and a punch is used to fit the hollow shaft. There has also been a method in which a core metal is pressed and compressed in the axial direction to form an arcuate recess.

[0003]

[Problems to be solved by the device]

 The above-mentioned conventional product has a drawback that the core weight remains in the hollow shaft after the recess is formed, which increases the weight of the product. It is an object of the present invention to obtain a new hollow core metal for forming a recess in a hollow shaft, which solves the above-mentioned drawbacks.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a cylindrical cored bar main body that fits into the hollow portion of a hollow shaft, divides the cored bar main body in a radial direction to form a plurality of divided cored bars, This is a structure in which a molding recessed portion that is recessed in the axial direction is formed on the outer peripheral portion of a predetermined split cored bar.

[0005]

[Action]

 Since the present invention is configured as described above, when the split cored bars are assembled into a cylindrical shape and fitted into the hollow shaft, the split cored bars close the hollow portion of the hollow shaft. In this state, when the wall portion of the hollow shaft corresponding to the molding recess of the predetermined split cored bar is pressed by the punch in the axial direction, the wall portion is pressed by the punch and the molding recess to have a predetermined shape. A recess that is recessed in the axial direction is formed. After this recess is formed, if another split core bar having no forming recess is pulled out from the hollow shaft, a predetermined split core bar having the forming recess falls downward in the hollow shaft, and the forming recess is formed in the hollow shaft. To leave. As a result, the predetermined split cored bar having the molding recess can be pulled out from the hollow shaft.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. First, as shown in FIGS. 1 and 2, a core metal main body 1 is formed from carbon steel for machine structure (S40C) or die steel. In this core metal main body 1, three molding recesses 2a, 2b and 2c which are recessed in the axial direction are formed in parallel in the longitudinal direction in the longitudinal intermediate portion of the upper part of the cylindrical main body 1a. Next, as shown in FIGS. 3 and 4, the main metal core body 1 is radially divided into Y-shapes to form three divided metal cores 2, 3 and 4, and the molding recesses 2a, 2b and 2c are formed. Only the upper split core metal 2 holds it.

A hollow shaft formed by assembling each of the split core bars 2, 3 and 4 into a columnar shape and cutting them into a metal pipe material such as STKM12C into a predetermined size as shown in FIG. Closely fit in the right part of 5. In this state, as shown in FIG. 6, the punch 6 having the three arc-shaped projections 6a, 6b, 6c formed in the lower part thereof is directed toward the forming recesses 2a, 2b, 2c of the split metal core 2 in the upper part. The recesses 5a, 5b, 5c are formed by driving and wall deformation of the wall of the hollow shaft 5 corresponding to the molding recesses 2a, 2b, 2c under pressure in the axial direction.

After forming the recesses 5a, 5b, 5c, the lower split cored bars 3 and 4 are pulled out from the hollow shaft 5 as shown in FIG. 8, and the upper split cored bar 2 is hollowed as shown in FIG. The molding recesses 2a, 2b, 2c are dropped in the shaft 5 to separate from the recesses 5a, 5b, 5c of the hollow shaft, and then the split core metal 2 is pulled out from the hollow shaft 5. In this case, the divided cored bars 2, 3 and 4 are divided in such a manner that the drop amount H2 of the upper divided cored bar 2 inside the hollow shaft 5 is larger than the depth H1 of the molding recesses 2a, 2b and 2c. Set.

According to the above-mentioned embodiment, the split cored bars 2, 3, 4 of the hollow shaft 5 close the inside of the hollow shaft 5 in which the recesses 5a, 5b, 5c are molded, and the split cored bar 2 on the upper side. Since the molding recesses 2a, 2b, 2c are formed in the inner wall of the punch 6, when the wall facing the molding recesses 2a, 2b, 2c is compressed and deformed by the punch 6 in the axial direction, the wall of the projection 6a, The high precision concave portions 5a, 5b, 5c are formed by being pressed by the concave portions 6b, 6c and the molding concave portions 2a, 2b, 2c, and the portions adjacent to the concave portions 5a, 5b, 5c are not deformed. Further, since the split cored bars 2, 3, 4 can be removed from the hollow shaft 5 after the recesses 5a, 5b, 5c are molded, the weight is reduced.

FIG. 10 shows a second embodiment. This is a hollow shaft in which the above-mentioned core metal main body 1 is vertically divided into two parts, and the upper divided core metal part 2-1 is notched so that its width W1 is substantially equal to the width of the molding recesses 2a, 2b, 2c. The amount of drop within 5 is increased, the lower split cored bar 2-2 is formed in a semi-cylindrical shape, and the others are the same as in the first embodiment described above. Also in this product, when the lower split cored bar 2-2 is pulled out from the hollow shaft 5 after the recesses 5a, 5b, 5c are formed, the upper split cored bar 2-1 falls downward inside the hollow shaft 5 and The molding recesses 2a, 2b, 2c are detached from the recesses 5a, 5b, 5c of the hollow shaft, whereby the upper split core metal 2-1 can be pulled out from the hollow shaft 5. The numbers of the projections 6a, 6b, 6c of the punch 6 and the molding recesses 2a, 2b, 2c are set appropriately according to the type of product.

[0011]

[Effect of the device]

 As is clear from the above description, the present invention can form a highly accurate recess in the hollow shaft and can remove the split cored bar after forming the recess, so that the weight of the product does not increase. Play.

[Brief description of drawings]

FIG. 1 is a side view of a core metal main body showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a side view of a split cored bar showing an embodiment of the present invention.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a partial cross-sectional side view of a split cored bar fitted to a hollow shaft.

FIG. 6 is a cross-sectional side view of essential parts of a hollow shaft in a recessed state.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a cross-sectional view showing a state in which a lower split cored bar is pulled out from the hollow shaft.

FIG. 9 is a cross-sectional view showing a state where an upper split cored bar has dropped inside the hollow shaft.

FIG. 10 is a sectional view corresponding to FIG. 7, showing another embodiment of the present invention.

[Explanation of symbols]

 1 core metal main body 1a main body 2 split core metal 2a molding recess 2b molding recess 2c molding recess 3 split core metal 4 split core metal 5 hollow shaft 5a recess 5b recess 5c recess 6 punch 6a projection 6b projection 6c projection

Claims (1)

[Scope of utility model registration request] 1. A cylindrical cored bar main body which fits into a hollow portion of a hollow shaft is provided, and the cored bar main body is radially divided to form a plurality of divided cored bars. A core metal for forming a recess in a hollow shaft, characterized in that a molding recess which is recessed in the axial direction is formed on the outer peripheral portion.