JPH0747500A - Formed part thickness control method in crank press - Google Patents

Abstract

PURPOSE:To improve the thickness accuracy of a press formed part by setting a striking load larger than a load required for forming, and controlling the striking load by other abutting face than a metallic die. CONSTITUTION:On a bed 1, the lower metallic die 3 is provided through the lower bolster 2. On the lower face of a slide 4, the upper metallic die 6 is provided through the upper bolster 5. They are installed a press frame A and the slide 4 is allowed to ascend and descend by a crank mechanism. In addition to the upper and the lower metallic dies 3, 6, abutting faces 9, 10 which are adjacent to both the metallic dies 3, 6 and abut on each other before the upper and lower metallic dies 6, 3 are closed at the time of descent of the slide 4 are provided. A striking load of a press is set larger than load required for forming, for instance, to 1.05-1.15 folds. Subsequently, at the time of forming operation, the striking load of the press is controlled by allowing the abutting faces 9, 10 to abut on each other. In such a way, thickness of a formed part can be controlled so as to be constant without being influenced by a fluctuation of the load required the forming of a material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a crank press, especially a mold for forging a material between a lower mold on a bed and an upper mold mounted on an ascending / descending slide. The present invention relates to a method for controlling the thickness of a molded product in a crank press having a contact surface adjacent to the mold.

[0002]

2. Description of the Related Art Generally, in a crank press,
An upper die attached to a slide that moves up and down via a crank mechanism is pressed against the material placed on the lower die for molding.

[0003]

However, the conventional crank press of this type has the advantages that the molding speed is fast and the amount of slide stroke is constant, but on the other hand, the mold temperature, material temperature, lubrication state of the mold, etc. It is unavoidable that the die hitting load varies due to the difference in the hitting conditions and the change in the shut height due to the temperature change of the die, slide and frame. As a result, different stamping loads are applied to the molding material, which inevitably suffers from the drawback that the thickness of the molded product is not constant. It is an object of the present invention to prevent the thickness of a molded product from changing due to variations in the stamping load of the press due to variations in the stamping conditions and the shut height amount, and to improve the thickness accuracy of the press molded product. .

[0004]

According to the present invention, there is provided a crank press having a lower die mounted on a bed and an upper die mounted on a slide, the slide being moved up and down by a crank mechanism. In addition to the lower mold and the upper mold, a contact surface adjacent to both molds is provided on the bolster or the mold holder so that the upper and lower molds come into contact with each other before the mold is completely closed when the slide descends. In addition, the stamping load of the press is set to be larger than the load required for molding, preferably 1.05 times to 1.15 times the load required for molding, and the contact surfaces contact each other during the molding operation. A method for controlling the thickness of a molded product in a crank press, characterized in that the punching load of the press is controlled by bringing them into contact with each other. In the method for controlling the thickness of a molded product in the crank press, the bed and the slide are provided with a plurality of lower molds and upper molds respectively, and the shut height is adjusted according to the presence or absence of a molding material in each mold. A method for controlling the thickness of a molded product in a crank press, which is characterized in that the punching load is controlled.

[0005]

According to the method for controlling the thickness of the molded product in the crank press of the present invention, the stamping load of the press is set to be larger than the load required for molding, and the contact surface (die kiss surface) of the mold holder or the bolster during molding. ) Are brought into contact with each other so that the sum of the load required for molding the molding material and the load supported by the contact surface (dye kiss surface) is controlled to be equal to the stamping load. The contact surface absorbs the fluctuation of the punching load due to the fluctuation of the height, and forging can be performed with less fluctuation of the thickness of the molded product.

[0006]

EXAMPLES The present invention will be described below with reference to examples.
For convenience of description, first, a crank press for carrying out the method of the present invention will be described. Although FIG. 1 and FIG. 2 show different embodiments, since the basic configuration is the same, the same parts will be described together.

Referring to FIGS. 1 and 2, reference numeral 1 is a bed, and a lower die 3 is provided on the bed 1 via a lower bolster 2. Reference numeral 4 denotes a slide, and an upper die 6 is provided on the lower surface of the slide 4 via an upper bolster 5. And
The bed 1, the lower bolster 2, the lower mold 3, the slide 4,
The upper bolster 5 and the upper die 6 are housed inside a press frame A partially shown in FIG. 1, and the slide 4 is moved up and down by a well-known crank mechanism (not shown) so that the upper die 3 is moved relative to the lower die 3. The mold 6 is designed to be opened and closed.

The above construction is the same as that of a known crank press, but in the present invention, the following construction is added.
In the example of FIG. 1, the lower mold 3 is mounted on the lower bolster 2 via a lower mold holder 7, and the upper bolster 5 is mounted on the upper mold 6 via an upper mold holder 8. Is installed. The heights of the facing surfaces 9 and 10 of the lower mold holder 7 and the upper mold holder 8 facing each other will be described later from the height of the facing surface of the lower mold 3 and the upper mold 6, that is, the height of the parting surface. The amount is set high. Therefore, the facing surfaces 9, 1
Reference numeral 0 denotes a contact surface, that is, a so-called die kiss surface, which contacts the molds 3 and 6 before the molds 3 and 6 are closed.

In the example of FIG. 2, the lower bolster 2 and the upper bolster 5 are provided with abutting surfaces 9a, 10a adjacent to the mounting surfaces of the molds 3, 6 and facing each other.
The height of 10a is the same as in the case of FIG.
The height is set to be higher than the height of the parting surface, and the height can be adjusted by the wedge mechanisms 11 and 12.

Next, referring also to FIG. 3, the slide 4 is provided with the shut height adjusting mechanism shown in FIG. This shut height adjusting mechanism connects a connecting shaft 13 that connects a crank mechanism (not shown) and the slide 4 via an eccentric shaft 14, and the eccentric shaft 14 is electrically driven via a worm / worm wheel 15. Or hydraulic motor 16
By rotating the slide 4 to adjust the position of the slide 4, the gap between the bed 1 and the lower surface of the slide 4, that is, the so-called shut height H is controlled. 1
7 is a position sensor for detecting the position of the slide 4, and 18
Is a detector for detecting the presence / absence of a molding material or a molded product in the lower mold 3 or, when having a plurality of molds, detecting the arrangement (presence / absence) of the molding material in each mold.

The shut height adjusting mechanism is
The shut height control device 19 calculates the shut height H based on the input (setting) signals such as the pressing force, the arrangement of the molding material, the presence or absence of the molding material, and the calculated value and the position signal from the position sensor 17. And a drive signal is output to the motor 16 and a predetermined shut height H
It is controlled to become.

Next, the method of the present invention will be described using the above apparatus. Once the molded product is determined, a known method is used to calculate what the load required for molding should be, and the shut height adjusting mechanism is operated so that the stamping load becomes the load required for molding. It suffices to adjust the shut height amount so as to obtain the shut height H. As described above, in the crank press, especially in the hot forging crank press, as described above, the temperature of the material to be molded, the die, It is known that the stamping load (load required for molding) changes depending on the stamping conditions such as the lubrication state and the change of the shut height due to temperature changes, etc.
And it is practically impossible to eliminate it.
It is empirically known that the fluctuation of the stamping load (load required for molding) is about ± 5 to 15% with respect to the set load in an ordinary crank press.

Therefore, in the method of the present invention, it is necessary to provide the die kiss surfaces (abutting surfaces 9 and 10) adjacent to the die so that the die kiss surfaces are always brought into contact with each other at the time of molding. When the fluctuation of the stamping load is + (plus), it is possible to prevent the load more than the setting from being applied when the fluctuation is equal to the load required for the molding material, but when the fluctuation is negative (-), the molding material is It is not possible to add the necessary load to. Therefore, in the present invention, a punching load that is at least as large as that is set in the shut height control device 19 so that the required load can be added even when the variation of the punching load acts negatively (-). .

Therefore, as can be seen from the molding process diagrams shown in FIGS. 4 (A) to 4 (C), the molding material M ₁ is inserted between the molds 3 and 6, and the slide is lowered to move the upper mold 6 up. When pressed to the lower die 3 side, as shown in the right half of FIG. 4 (B), the contact surfaces 8 and 9 provided on the die holders 7 and 8 are in contact with each other (dye kiss).
At the same time, the molding material M ₁ in the molds 3 and 6 is compressed to mold the molded product M ₂ . d ₁ is the bending amount (deformation amount) of the press body when a load necessary for molding is applied to the molded product. Usually, the molding is completed by this, but in the present invention, as described above, in consideration of the fluctuation of the stamping load, the stamping load is made larger than the load necessary for the molding, and as much as that, FIG.
As shown in (4), the contact surface (daikiss surface) is further pressed, and the press body further bends (deforms) by d ₂ . However, since the influence of this deformation on the molds 3 and 6 can be ignored,
The thickness (shape) of the molded product M ₂ is substantially the same.

Next, an example of performing multi-step molding or simultaneous molding using a plurality of molds according to the method of the present invention will be described with reference to FIG.
Will be described with reference to. First, the shut height H is initialized (step S1). For the initial setting of the shut height H, the position of the slide 4 is adjusted so that, for example, the press die hitting load is 1.15 times the load required for maximum forming for the reason described above.

Next, for example, the detector 18 detects the arrangement state of the molding material in the plurality of molds, and the output signal thereof is input to the shut height controller 19 (step S2). With this input signal, the control device 19
In advance, the load required for molding set in advance according to the arrangement of the molding material is read and input to the molding load setting device.

The load required for molding set in the molding load setting device will be described below. For example, a case will be described in which a multi-step die has a die row of three steps, and the molding material is sequentially transferred to the die one by one. In advance
By calculation or simulation, for example, when the molding material is present only in the first step of the mold row, the load p ₁ required for the molding is 430 tf, and when the molding material is present only in the second step, the molding is performed. The load p ₂ required for the molding is determined to be 870 tf, and when the molding material is used in the first and third steps, the load p ₃ required for the molding is determined to be 1300 tf.

Then, the press height driving load is calculated by the shut height control device 19 based on the load required for molding set corresponding to the arrangement state of the molding material and the detection signal from the detector 17 ( Step S3). That is, as a unique value that differs for each crank press,
When the variation value acting on the- (minus) side of the stamping load with respect to the load required for molding is 15% of the load required for molding, press stamping when there is molding material only in the first step of the mold row. The load P ₁ is P ₁ = p ₁ × 1.15 = 430 × 1.15≅500 tf When the molding material is used only in the second step of the mold row, the press-molding load P ₂ is P ₂ = p ₂ × 1.15 = 870 × 1.15≈1000t
f When the molding material is used in the first and third steps of the mold row, the pressing force P ₃ is P ₃ = p ₃ × 1.15 = 1300 × 1.15≈1500
It becomes tf.

The shut height increase / decrease amount Δh is calculated from the press die hitting load by the following equation. (Step S4) Δh = ΔP × α α: Press spring constant (here, for example, at 1600 tf, it is assumed to be 1.5 × 10 ⁻³ mm / t) ΔP = Maximum punching load−Punching load Therefore, maximum If initializes the stamping load 1500Tf, shut height decrease amount △ h ₁ in the case where there is a molding material only into the first step of the mold _{string, △ h 1 = △ P 1} × α = (1500-500) × 1.5 ×
10¯ ³ = 1.5mm shut height amount △ h ₂ when only the initial setting second step of 1.5mm rise die columns than level there is material in _{the, △ h 2 = △ P 2} × α = (1500- 1000) x 1.5
× 10¯ 0.75mm higher than ³ = 0.75 mm initial setting level, the time-series 0.7
Shut height amount △ h ₃ when there is material only in the first and third step of 5mm drop die _{column, △ h 3 = △ P 3} × α = (1500-1500) × 1.5
× 10 − ³ = 0 Same as the initial setting level. The time series is 0.75mm.

Based on this shut height amount, the shut height control device outputs a motor drive command signal to the motor 16 to adjust the shut height H (step S).
5). The shut height H is adjusted by, for example, comparing and calculating the present shut height amount detected by the position detector 17 and the adjusted shut height amount by the shut height control device 19 and using the difference as the adjustment amount. Motor 1
Output to 6. The shut height H is adjusted while the slide 4 is moving up, down, or stopped, that is, when the slide 4 is not at the bottom dead center, depending on the arrangement state of the molding material in the mold row to be processed next. Do it. Further, in the above-described embodiment, the case where the molding material is sequentially changed to three ways in the multi-step mold has been described. However, when the same processing is simultaneously performed by a plurality of molds, the molding material is partially applied to the plurality of molds. Needless to say, it can be applied to the case where there is no case.

[0021]

As described above, according to the method for controlling the thickness of the molded product of the crank press of the present invention, the stamping load is set to be larger than the load required for molding, and the stamping load is set adjacent to the mold separately from the mold. Since the contact surface is provided and the load exceeding the load required for molding is received by the contact surface, the thickness of the molded product can be controlled to be constant without being affected by the fluctuation of the load necessary for molding the material. In addition, the die kiss load is set within a range that can be absorbed by the press body, so that sticking does not occur and operation is not hindered.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment in which upper and lower die holders are brought into contact with each other.

FIG. 2 is a perspective view of an essential part showing an embodiment in which upper and lower bolsters are provided with contact surfaces.

FIG. 3 is a schematic view of a shut height adjusting mechanism of the crank press of the present invention.

FIG. 4 is a molding process diagram according to the method of the present invention.

FIG. 5 is an operation flowchart in the embodiment of the present invention.

[Explanation of symbols]

 1 bed 2 lower bolster 3 lower mold 4 slide 5 upper bolster 6 upper mold 7,8 mold holder 9,10 contact surface (dye kiss surface) 16 motor 17 detector 19 shut height control device

Claims (4)

[Claims] 1. A crank press having a lower mold mounted on a bed and an upper mold mounted on a slide, wherein the slide is moved up and down by a crank mechanism.
Aside from the lower mold and the upper mold, adjacent to both molds, a contact surface is provided which contacts the upper and lower molds before the molds are completely closed when the slide descends. A method for controlling the thickness of a molded product in a crank press, wherein the load is set larger than that required for molding, and the abutting surfaces are brought into contact with each other during a molding operation to control the stamping load of the press. 2. A molded product thickness control method in a crank press according to claim 1, wherein the contact surface is provided on a bolster or a mold holder. 3. The method for controlling the thickness of a molded product in a crank press according to claim 1, wherein the stamping load of the press is 1.05 to 1.15 times the load required for molding. . 4. The bed and slide are provided with a plurality of lower molds and a plurality of upper molds respectively, and the shut height H is adjusted according to the presence or absence of molding material in each mold to control the stamping load of the press. The method for controlling the thickness of a molded product in a crank press according to claim 1, 2, or 3, characterized in that.