JP2829818B2 - Shearing method and wall-shearing mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shearing process for preventing a reduction in thickness of a product due to sagging at a shearing portion when a sheet metal is sheared by a press machine, and for obtaining a product with good precision. The invention relates to a method and to a mold used in an intermediate step in the practice of the method.

[0002]

2. Description of the Related Art As a means for finishing a product profile with high precision by shearing with a press machine, there is a method shown in FIG. In FIG. 8A, a is a die, b is a punch for removing a work, and the clearance c is relatively large in order to reduce the shear resistance, so that a large dripping d and a crack e occur during shearing. As a result, the thickness of the work near the shear surface becomes thin. Thick Therefore, even when the finishing process using the finishing shaving punch b ₂ of the shaving punch b ₁ and 8 in FIG. 8 (b) (c), because the removal amount is small, based on the sagging d and crack e It is difficult to recover the decrease.

[0003] Therefore, when high precision is expected in size and shape, means for finishing by milling is often used, and it is inevitably expensive.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to finish a profile without reducing the thickness of a work by press working.

[0005]

According to a first aspect of the present invention, there is provided a method for rough-working a workpiece with an upper die and a lower die, and a method of performing a roughing process from an inner side to an outer side of a surface to be finished. The work is supported by a lower mold having a step lower than the work mounting surface, and the lower surface of the work is projected to the step while the upper mold having a shearing blade half-punches the outside of the surface to be finished to near the lower end. It is characterized by comprising a thickening step and a finishing step of shaving and shearing the work along the surface to be finished.

According to the second aspect of the present invention, the mold used in the intermediate step has a stepped portion slightly lower than the workpiece mounting surface provided from the inside to the outside of the surface to be finished. It is characterized by comprising a mold, and an upper mold having a shearing blade that moves up and down along a processing surface set slightly outside the surface to be finished.

[0007]

In the method according to the first aspect, the work obtained in the pre-punching step having the finishing allowance is sheared slightly outside the surface to be finished to near the lower end in the next thickening half-punching step, and the half-punching is performed. In this state, the half blank portion is pushed into the lower mold step with the upper mold pressure together with the inner portion thereof, and the thickness near the shearing portion increases. When shaving shearing is performed in the next finishing step including the portion having the increased thickness, the thickness of the sheared portion becomes approximately equal to the thickness of the inner portion of the work.

[0008] In the mold according to the second aspect, the first aspect.
In the description of the operation described above, the part where the sag of the work is large is half-punched with the upper die, and the half-punched meat is pressed into the step of the lower die, so that the part close to the half-punched surface is increased in thickness.

[0009]

An embodiment will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a ratchet used for a side brake of a four-wheeled vehicle. The ratchet includes a shaft support hole 2 at the center, a claw 3 at one end, and an engaging portion 4 of an operating rod at the other end. The ratchet 1 is, for example, punched from a steel plate having a thickness of 4 mm. When the ratchet 1 is used, a large force is applied to the pawl 3. Therefore, in order to ensure the engagement state and provide durability, the pawl 3 It is required that the profile be accurate and the thickness be not less than the plate thickness.

[0010] FIG. 2 shows the work 1 ₁ punched from steel plate,
The work 1 _1, finishing allowance 3 on the outside of the finish scheduled surface of the nail 3
₁ is provided, but the other parts are not finished and are left in a punched state. The workpiece 1 _1, and FIG. 2 (b)
As is apparent from the above, sagging d at the time of punching occurs at a corner of one surface. The sagging d may be present at a place other than the nail 3, but must be removed from the nail 3.

FIG. 3 shows an example of the use of the ratchet 1, wherein 5 shows the entire side brake operation section,
Is fixed to the vehicle body by a ratchet gear having teeth 6a.
The brake lever 7 is connected to the ratchet gear 6 by a pin 7a.
The brake pulling wire 7c is connected to a pin 7b provided near the pin 7a, the ratchet 1 is pivotally connected to the pin 7d, and a grip 7e is continuously provided on the distal end side. An operating rod 8 is inserted movably in the longitudinal direction, is urged by a spring 8b so that a push button 8a at the tip projects, and a hook 8c at the other end is engaged with the engaging portion 4 of the ratchet 1. I agree.

When the brake lever 7 is pulled up, the brake pull wire 7c is pulled to operate a brake (not shown).
The brake lever 7 is locked by the engagement between the pawl 3 and the teeth 6a, and the lock is released by pressing the push button 8a.

FIG. 4 et seq. Show a mold used in the manufacturing process of the ratchet 1. The mold 10 shown in FIG.
1 by shearing the outer portion of the finishing allowance 3 ₁ provided in _one of the claws 3 Figure 2 to reduce the width of the sagging d in (b), used in the prior punching process.

The front die 10 includes a die 11, a punch 1
4 (a) and 4 (b), the die 11 is provided with a hole 13 in the vertical direction and a lower blade 14 projecting into the hole 13 in a peninsula shape. A guide 15 is provided on the open side of the reference numeral 13. The ridge line 14a of the lower blade 14 becomes a blade portion.

FIG. 4C is a bottom view of the punch 12 in which an upper blade 16 cooperating with the lower blade 14 of the die 11 is formed in a bay shape.

The workpiece 1 ₁ is placed as shown in phantom were fixed in an unillustrated fixing means and descends along the punch 12 in the guide 15 and the holes 13, finishing allowance 3 shown in FIG. 2 (a) ₁
7, that is, the outer portion of the portion having the sag d
(A) or as shown in FIG. 8 (a).

The mold 20 of Figure 5 is a mold used to increase meat half punching step, the die 21, slightly smaller lower blade 24 and the upward guide 25 than the form of the distal end side of the work 1 ₁ claw 3 is provided Can be The outer line 24a of the lower blade 24 corresponds to the claw 3 shown in FIG.
A little smaller than the virtual outline of. The hole 23 is extremely shallow, and the bottom is a step 23a. on the other hand,
The upper blade 26 of the punch 22 is slightly larger than the virtual outline, and the blades 24 and 26 have a relatively large clearance.

The stroke of the punch 22 is set to the stroke of half blanking that does not reach the lower surface of the workpiece 1 _1, FIG. 5
It is lowered to the position shown in FIG. Finishing allowance 3 ₁ of the work 1 ₁ is half blanking in slightly outside the finished scheduled surfaces, FIG. 5 (a), the Hami out portion 3 ₂ is extruded onto the stepped portion 23a as shown in FIG. 7 (b) And pressurized. The extrusion and the pressure by the excision of the portion with sag d, the thickness of the finished scheduled surface, that is, the thickness of the claws 3, made in the thickness of the workpiece 1 ₁ and more equal.

FIG. 6 shows a finishing mold 30 in which a die 31 is provided with a lower blade 34 having the same shape as the claw 3 side of the product and an upward guide 35 , and protrudes into a hole 33. Upper blade 36 of the punch 32 is intended to have a slight clearance between the lower blade 34, after thin shaving sheared finished scheduled surface lowers the punch 32 to shear the outer peripheral side of the Hami out portion 3 _2. The working surface of the punch 32 coincides with the shaving surface indicated by the symbol S in FIG. After the shearing, the inner peripheral side of the extruded portion remains on the product side as shown in FIG. 7C, so that it becomes a part of the thickness of the product, and the original thickness is maintained.

The step formed on the lower surface of the claw 3 by the step 23a can be flattened by pressing in the thickness direction before or after the step of FIG. Also, if punching of workpiece removal can be done with relatively little dripping,
The punching can be a pre-punching step.

[0021]

As is apparent from the above description, according to the first and second aspects of the present invention, the sag portion generated on the work can be removed using only the mold, and the plate thickness of the shearing portion can be reduced. Therefore, there is an advantage that a member having an accurate shape can be made extremely efficiently and inexpensively.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a product manufactured by implementing the present invention.

FIG. 2 is a plan view and a cross-sectional view of the material of the product.

FIG. 3 is a sectional view of a usage example of the product.

FIG. 4 shows a mold in a pre-punching step, (a) is a sectional view,
(B) is a plan view of the die, and (c) is a bottom view of the punch.

5 (a) is a cross-sectional view, FIG. 5 (b) is a plan view of a die, and FIG. 5 (c) is a bottom view of a punch.

6 (a) is a cross-sectional view, FIG. 6 (b) is a plan view of a die, and FIG. 6 (c) is a bottom view of a punch.

FIG. 7 is a process explanatory view of the present invention.

FIG. 8 is a process explanatory view of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ratchet 1 1 Work 3 Claw 3 ₁ Finishing allowance 3 ₂ Slip-out part 11,21,31 Die 12,22,32 Punch 23
a step

Claims (2)

(57) [Claims] 1. A pre-punching step for roughing a work with an upper die and a lower die, and a work mounting surface from inside to outside of a surface to be finished
A work of supporting the work with a lower mold having a lower step, and an upper mold having a shearing blade, wherein the outer surface of the surface to be finished is half-cut to near the lower end, and the lower surface of the work projects to the step. A finishing step of shaving and shearing the workpiece along a predetermined plane. 2. A lower mold having a stepped portion slightly lower than a workpiece mounting surface extending from the inside to the outside of a surface to be finished, and a shearing blade which moves up and down along a processing surface set slightly outside the surface to be finished. And an upper mold provided with a thickening shearing mold.