JP3086981B2 - Reinforcement method of mounting plate part in sheet metal pulley - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing a mounting plate in a sheet metal pulley, and more particularly to a method for reinforcing a mounting plate provided with a mounting hole for a boss fitted on a spindle or a rotating shaft.

[0002]

2. Description of the Related Art Sheet metal pulleys manufactured by performing sheet metal working on a metal sheet material are conventionally known. FIG. 6 shows a pulley for a flat belt, FIG. 7 shows a pulley for a V belt, and FIG. The respective pulleys are partially shown in cross section. The cross-sectional shape of each of these pulleys is cup-shaped, and a mounting hole 2 is formed in the mounting plate portion 1, a boss 100 is fitted into the mounting hole 2, and a flange portion 101 of the boss 100 is connected to the mounting hole 2. The peripheral portion 3 is overlapped and joined, and means such as welding is selected for joining. Reference numeral 4 denotes a penetration part by welding.

In these sheet metal pulleys, mounting holes 2
Increasing the dimensional accuracy of the diameter D is useful for improving the mounting accuracy of the boss 100, and increasing the strength of the peripheral portion 3 of the mounting hole 2 is useful for securely mounting the boss 100. . Therefore, conventionally, the strength of the peripheral portion 3 of the mounting hole 2 has been secured by forming the mounting hole 2 in a thick plate material.

[0004]

However, if the method of forming the mounting holes 2 in a thick plate material is adopted, there is a problem in that there is a restriction in improving the drilling accuracy by the thickness of the plate material. .

Further, as can be seen from FIGS. 6 to 8, in each pulley, a portion other than the peripheral portion 3 of the mounting hole 2 is not required to have much strength. 3 can be formed thinner.

However, in order to secure the strength of the peripheral portion 3 of the mounting hole 2, if a pulley is manufactured using a plate material having a thickness corresponding to the strength, not only the peripheral portion 3 of the mounting hole 2 but also the entire pulley is manufactured. Since the thickness becomes unnecessarily thick, there is a problem that the material cost is extremely increased and the weight of the obtained sheet metal pulley is significantly increased.

The present invention has been made in view of the above problems, and an object of the present invention is to make the peripheral portion of the mounting hole have a thickness suitable for required strength even when a thin plate material is used. It is an object of the present invention to provide a method of reinforcing a mounting plate portion in a sheet metal pulley which can be provided.

[0008]

According to the present invention, there is provided a method of reinforcing a mounting plate in a sheet metal pulley, comprising the steps of: mounting a plate in a sheet metal pulley having a mounting plate having a mounting hole for a boss and a belt winding portion; A drilling step of opening a hole smaller in diameter than the mounting hole in a portion corresponding to the plate portion, and the entire periphery of the hole smaller in diameter than the mounting hole, the diameter of the smallest diameter portion is the hole A burring step of forming a truncated conical protrusion larger than the diameter of the portion, and the protrusion having a diameter of the smallest diameter portion of the protrusion formed in the burring step kept longer than the diameter of the hole. To make the portion thick by flattening.

[0009]

In the above-described method for reinforcing the mounting plate portion of the sheet metal pulley, the diameter of the hole formed through the thickening step is adjusted by adjusting the diameter of the mounting plate portion of the mounting plate portion of the final product, the sheet metal pulley. If the diameter is set to be the same as the diameter of the mounting hole, the peripheral portion of the mounting hole becomes thicker through the thickening step, and is reinforced accordingly. The point at which the peripheral portion of the mounting hole is reinforced by thickening is a thickening step performed after the drilling step and the burring step. Therefore, the drilling step and the burring step are performed on a thin plate material. Will be

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of reinforcing a mounting plate portion in a sheet metal pulley according to the present invention includes a punching step, a burring step, and a thickening step. In the method of reinforcing the mounting plate portion in the sheet metal pulley according to the embodiment, a burring step (FIGS. 2 and 4) and a thickening step (FIGS. 3 and 5) are divided into two stages. In the embodiment of the present invention, not only the upper mold and the lower mold, but also the auxiliary mold is used depending on the case. Further, a plate member (hereinafter, referred to as a work) W has a bottom plate portion 6 corresponding to the mounting plate portion 1 (see FIGS. 6 to 8) and a belt winding portion 5 (see FIGS. 6 to 8). The corresponding peripheral plate 9 has already been formed by sheet metal working. Hereinafter, a specific description will be given with reference to FIGS.

(1) Drilling Step (FIG. 1) In this step, a hole 7a smaller in diameter than the mounting hole 2 (see FIGS. 6 to 8) is formed in the bottom plate 6 of the work W.
The thickness of the bottom plate 6 is T1 in FIG. 1, and the diameter of the hole 7a is D1.
It is represented by

In this step, a lower die 51 and an upper die 61 for punching are used, and the center of the bottom plate portion 6 of the work W placed on the lower die 51 is punched by the upper die 61 so as to have the above-described diameter. A small hole 7a is opened.

(2) Burring Step (First Burring Step: FIG. 2) In this embodiment, the burring step is divided into a first burring step shown in FIG. 2 and a second burring step shown in FIG. In these steps, the diameter of the smallest diameter portion is smaller than the diameter of the hole portions 7a, 7b over the entire periphery of the hole portions 7a, 7b smaller in diameter than the mounting hole 2 described with reference to FIGS. This is also a step of forming the large frustoconical projections 8a and 8b. Here, the first burring step of FIG. 2 will be described.

In the first burring step, a lower mold 52 having a convex part 52a and a spherical molding surface 52b capable of fitting the hole 7a opened in the hole making step in a positioned state.
And a vertically movable auxiliary mold 5 disposed around the lower mold 52.
3 and an upper die 6 having a downwardly expanding tapered forming surface 62a.
2 is used. That is, as shown in the left half of FIG. 2, the hole 7 a of the work W is fitted and positioned in the protrusion 52 a of the lower mold 52, and the bottom plate 6 of the work W is supported by the auxiliary mold 53. From this state, the work W is lowered by lowering the upper die 62 as indicated by an arrow X1 (at this time, the auxiliary die 53 is processed together with the work W). In this way, each time the workpiece W is hit, the hole edge 7a of the hole 7a
a ′ is rubbed while being expanded on the molding surface 52b of the lower die 52, and is lifted until it hits the molding surface 62a of the upper die 62.
As shown in the right half of the figure, a frusto-conical projection 8a is formed. The diameter of the smallest diameter portion of the protrusion 8a thus formed, that is, the diameter of the inner peripheral surface of the upper end of the protrusion 8a is larger than the diameter D1 of the hole 7a opened in the drilling step.

(3) Thickening Step (First Thickening Step: FIG. 3) In this embodiment, the thickening step is the first thickening step shown in FIG. 3 and the thickening step shown in FIG. This step is divided into a second thickening step. In these steps, the protrusions 8a and 8b formed in the burring step use two molds without changing the diameter of the smallest diameter part. This is a step of thickening the portion by tapping and flattening. Here, the first thickening step in FIG. 3 will be described.

In the first thickening step, the outer diameter of the protrusion 8a formed in the first burring step is the same as the diameter of the smallest diameter part, and the protrusion amount is slightly longer than the thickness dimension of the work W. Convex portion 54a and a horizontal and flat molding surface 54b
, A vertically movable auxiliary die 55 disposed around the lower die 54, and an upper die having a horizontal pressing surface 63a and a vertical surface 63b for preventing the work W from expanding in diameter. 63 is used. That is, as shown in the left half of FIG. 3, by positioning and placing the bottom plate 6 of the work W on the auxiliary mold 55, the protrusion 8 a is opposed to the molding surface 54 b of the lower mold 54. By lowering the upper die 63 from this state as indicated by an arrow X2, the protrusion 8a of the work W is hit, whereby the protrusion 8a is fitted to the protrusion 54a of the lower die 54, and the right half of FIG. Flatten the hit area as shown in (2). At this time, the work W and the auxiliary mold 55 are
Slightly depressed by 3. At this time, the vertical surface 63b of the upper die 63 is fitted to the peripheral plate portion 9 of the work W and the work W
Prevents the diameter from expanding.

In the first thickening step, the projection 8a is flattened without changing the diameter of the smallest diameter portion of the projection 8a formed in the first burring step, so that the projection 8a is flattened. The flattened portion (that is, the portion fitted to the convex portion 7b) is thickened by the material flow generated in the process. Therefore, the bottom plate 6 of the work W is provided with a hole 7b whose peripheral edge is thicker than the thickness of the work W at the time of departure. The diameter of the hole 7b obtained through the first thickening step is indicated by D2, and the thickness of the periphery of the hole 7b is indicated by T2.

(4) Burring Step (Second Burring Step: FIG. 4) In the second burring step, the convex portion 56 which can fit the hole 7b formed in the first thickening step in a positioned state.
a and a lower mold 56 having a spherical molding surface 56b, a vertically movable auxiliary mold 57 disposed around the lower mold 56, and an upper mold 64 having a downwardly expanding tapered molding surface 64a. Is used. The procedure is the same as the procedure for the first burring step described with reference to FIG. Therefore, detailed description is omitted. Projection 8 formed in the second burring step
The diameter of the smallest diameter portion of b, that is, the diameter of the inner peripheral surface of the upper end of the protruding portion 8b is larger than the diameter D2 of the hole 7b obtained through the first thickening step described with reference to FIG.

(5) Thickening Step (Second Thickening Step: FIG. 5) In the second thickening step, the outer diameter is the same as the diameter of the smallest diameter portion of the projection 8b formed in the second burring step. And a protrusion 58a whose protrusion amount is slightly longer than the thickness T2 of the peripheral portion of the hole 7b obtained through the first thickening step, and a horizontal and flat molding surface. A lower mold 58 having a lower mold 58b, a vertically movable auxiliary mold 59 disposed around the lower mold 58, a horizontal pressing surface 65a and a vertical surface 65b for preventing the work W from expanding in diameter. A mold 65 is used. The procedure is the same as the procedure for the first thickening step described with reference to FIG. Therefore, detailed description is omitted.

Here, the lower mold 5 used in the second thickening step is used.
Assuming that the same outer diameter as the diameter of the mounting hole 2 described with reference to FIGS. 6 to 8 is given to the outer peripheral diameter of the projection 58a of FIG. 8, the protrusion is obtained through the second thickening step. The hole is the mounting hole 2 itself, and its diameter D3 is larger than the diameter D1 of the hole 7b obtained through the first thickening step. Therefore, D3>D2> D1. Also,
The thickness T3 of the peripheral edge of the mounting hole 2 is larger than the thickness T2 of the peripheral edge of the hole 7b obtained through the first thickening step. Therefore, T3>T2> T1.

When the peripheral portion of the mounting hole 2 is thickened in this manner, even if a thin work is used for the work W at the time of departure, the thickened peripheral portion 3 of the mounting hole 2 can be used. The strength corresponding to the thickness is given. Further, the thickness of the work W at the time of departure may be adjusted to the thickness of the portion where thickening is not necessary, so that the portion other than the peripheral portion 3 of the mounting hole 2 in the sheet metal pulley which is the final product. Is not unnecessarily thick.

For the peripheral plate portion 9, at a stage after the thickness of the peripheral portion 3 of the mounting hole 2 is increased, or at an earlier stage, depending on the use of the pulley as a final product, Sheet metal processing for giving a shape corresponding to a flat belt, a V belt, a poly V belt, or the like is performed.

In the first thickening step of this embodiment,
Although the diameter of the smallest diameter portion of the projection 8a formed in the first burring step is flattened without changing the diameter, the diameter of the smallest diameter portion of the projection 8a is established in the drilling step. If it is a method of flattening the protruding portion 8a while keeping it longer than the diameter D1 of the hole 7a,
A method of flattening the projection 8a while maintaining a diameter smaller than the diameter of the smallest diameter portion of the projection 8a formed in the first burring step may be adopted. The same applies to the second thickening step, and the protrusion 8 formed in the second burring step is formed.
b, while keeping the diameter of the smallest diameter portion longer than the diameter of the smallest diameter portion of the projection 8a formed in the first burring step, the projection 8b is flattened.
A method of flattening the projection 8b while maintaining a diameter smaller than the diameter of the smallest diameter portion of the projection 8b formed in the second burring step may be adopted.

Further, in the above embodiment, each of the burring step and the thickening step is performed in two stages, but the required strength can be met by performing the burring step and the thickening step only once. If the thickness is obtained, then these steps only need to be performed once,
In the case where the thickness corresponding to the required strength cannot be obtained even if the burring step and the thickening step are performed twice each as in the example,
By performing each step in more steps, it is possible to obtain a thickness that meets the required strength.

Further, in the above embodiment, the bottom plate 6
Although the drilling process is performed on the work W on which the bottom plate portion 6 and the peripheral plate portion 9 are formed, the sheet metal working for forming the bottom plate portion 6 and the peripheral plate portion 9 on the flat work is performed after the drilling process. It may be performed in stages.

[0026]

According to the method of reinforcing the mounting plate portion in the sheet metal pulley according to the present invention, a hole corresponding to the mounting plate portion can be formed in a thin plate material. It can be performed with high accuracy. Similarly, it is possible to easily and accurately form a frusto-conical projection on the entire periphery of the hole formed in the drilling step for a thin plate material. In addition, since the reinforcement of the mounting plate portion is performed by increasing the thickness of only the peripheral portion of the portion corresponding to the mounting hole, the portion where high strength is not required can be thinned to reduce waste of material cost, Moreover, an increase in the weight of the sheet metal pulley can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a drilling step in an embodiment of the present invention.

FIG. 2 is an explanatory view of a first burring step in the embodiment of the present invention.

FIG. 3 is an explanatory view of a first thickening step in the embodiment of the present invention.

FIG. 4 is an explanatory view of a second burring step in the embodiment of the present invention.

FIG. 5 is an explanatory view of a second thickening step in the embodiment of the present invention.

FIG. 6 is a partial sectional view of a flat belt pulley to which a boss is attached.

FIG. 7 is a partial sectional view of a V-belt pulley to which a boss is attached.

FIG. 8 is a partial cross-sectional view of a poly-V belt pulley to which a boss is attached.

[Explanation of symbols]

 Reference Signs List 1 mounting plate portion 2 mounting hole 5 belt wrapping portion 6 bottom plate portion (portion corresponding to mounting plate portion) 7a, 7b holes 8a, 8b projecting portions 54, 58 lower die 63, 65 upper than mounting holes Mold 100 Boss W Work (plate material)

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21D 53/26 B21D 19/08 F16H 55/44 B23P 15/00

Claims (1)

(57) [Claims] 1. A sheet metal pulley having a mounting plate portion provided with a mounting hole for a boss and a belt winding portion, a hole having a diameter smaller than the mounting hole is formed in a portion corresponding to the mounting plate portion of the plate material. A burring step of forming a truncated conical protruding portion in which the diameter of the smallest diameter portion is larger than the diameter of the hole portion over the entire periphery of the hole portion smaller in diameter than the mounting hole. A step of increasing the thickness of the projection by flattening the projection while maintaining the diameter of the smallest diameter portion of the projection formed in the burring step longer than the diameter of the hole;
A method of reinforcing a mounting plate portion in a sheet metal pulley including: