WO2022030571A1

WO2022030571A1 - Die structure, pressing device, and pressing method

Info

Publication number: WO2022030571A1
Application number: PCT/JP2021/029067
Authority: WO
Inventors: 真一北角; 良淳池浦
Original assignee: 株式会社一志精工電機; 国立大学法人三重大学
Priority date: 2020-08-06
Filing date: 2021-08-05
Publication date: 2022-02-10
Also published as: CN116234646A; JPWO2022030571A1

Abstract

Provided is a die structure and so forth by which effects of unstable positioning precision due to a press main unit can be reduced, adjustment of a pressing device by an experienced worker is unnecessary, productivity is excellent, and attachment to and detachment from the press main unit is easy. A die structure 1 includes a lower die 3 fixed to a fixing stage 2, an upper die 4 provided above the lower die 3, a first elastic member 11 and a stopper 10 provided between the upper die 4 and the lower die 3, and a pressure adjusting device 6 linked to a movable stage 5 side of the upper die 4. When not applying pressure in pressing, the first elastic member 11 separates the upper die 4 and the lower die 3, and when applying pressure in pressing, a working piece 30 is interposed and pressed between the upper die 4 and the lower die 3 with pressure from the movable stage 5 applied to the upper die 4 via a second elastic member 8 from a pressure plate 7 of the pressure adjusting device 6, with the stopper 10 restricting the bottom dead point position of the upper die 4.

Description

Mold structure, press processing equipment, and press processing method

The present invention relates to a die structure for press working, a press working device using this die structure, and a press working method.

In various electronic devices, home appliances, industrial machines, automobiles, communication peripheral devices, etc., metal connector terminals and conductor rods (hereinafter collectively referred to as "connector terminals") are used to electrically connect multiple circuits and components. ") Is used.

For example, in hybrid and electric vehicles, whose production has been increasing remarkably in recent years, connector terminals play the role of relays, resistors, fuses, power sensors, etc., and are important parts for supplying, shutting off, and distributing high-voltage power. Is. In the future, it is expected that the number of electronic components mounted in the power supply box will increase in order to respond to higher voltage and improve safety and convenience. Along with this, it is necessary for the connector terminals to cope with higher densities, and there is a demand for connector terminals with finer processing.

The connector terminal is generally manufactured by pressing a thin metal material. Various methods are known as press working methods, such as single-shot working and progressive press working. In the case of single-shot machining, which is the simplest pressing method, dies required for each process such as shearing, bending, and drawing are prepared separately. In single-shot processing, it is necessary to put in and take out the material to be processed in each process, so the more processes there are, the more time it takes to manufacture, and the production efficiency tends to decrease. On the other hand, in progressive press processing, a plurality of processing processes are provided in one die, and each press processing is performed one after another while automatically feeding the material to be processed to the next process. It is not necessary to put the processed material in and out of the mold. Therefore, progressive press working is a processing method having the fastest processing speed and excellent production efficiency among various press processing methods, and is suitable for mass production.

In order to mass-produce connector terminals that have been finely processed, it is necessary to perform high-precision processing in a stable manner. Here, "high-precision machining" means that fine machining of the work material is performed so as to be within the target error range, and the dimensional change over time after the production of the product is within the predetermined range. It means to do it so that it fits in. The accuracy of machining is affected by both the accuracy of the mold itself as designed and the positioning accuracy of the upper and lower molds that make up the mold. As a result of increasing the demand level for microfabrication of connectors, the influence of the positioning accuracy of the upper mold and the lower mold becomes relatively large, and its improvement has become an important issue. Factors that affect the positioning accuracy of the upper and lower dies include wear of the press body, backlash of sliding parts, and expansion and contraction of the housing due to temperature changes. As a result, the bottom dead center position of the movable table may not be stable, and the pressure on the work piece (hereinafter, also referred to as “machining force”) may become unstable. Here, the bottom dead center means the time when the upper mold and the lower mold are closest to each other, and the bottom dead center position means the position when the upper mold and the lower mold are closest to each other. Further, the press machine main body is used as a general term for parts of a press processing apparatus that performs press processing, excluding dies and the like, for example, mechanical parts such as a movable table, a fixed table, and a housing.

Further, in bending by a press working device, there is a phenomenon called springback in which the angle becomes larger than the desired angle immediately after pressurization after bending the work material. As a countermeasure against springback, the introduction of a press processing device (hereinafter referred to as "servo press") having an advanced control function can be mentioned.

Since it is not easy to predict the factors that affect the positioning accuracy of the upper and lower dies mentioned above by calculation, at the production site, the die height adjustment of the press processing equipment and the correction of the dies based on the experience and intuition of skilled technicians, etc. Is being done. Here, the die height means the vertical distance between the bottom dead center position of the movable table of the press working apparatus and the fixed table.

Various methods have been proposed as methods for improving the positioning accuracy of the upper and lower dies. For example, as a press machine that improves positioning accuracy and shortens the optimum position search time, a press machine that cushions breakthroughs that occur during material punching by a buffer hydraulic cylinder provided between the upper and lower dies of the press machine. Is known (see Patent Document 1).

In addition, even if the stroke of the moving table or cam operated by the driving means changes due to the thermal influence or the inertial force at the time of starting and stopping, the amount of change in the stroke can be absorbed by the urging means, and the pressing force is predetermined. As a press device that can hold the pressure and improve the machining accuracy, the punch plate to which the punch is attached is not directly connected to the displacement operating member such as a rod or cam that is moved up and down by the driving means, but via an urging means. A press device using a free clamp system is known (see Patent Document 2).

Japanese Unexamined Patent Publication No. 10-58200 Japanese Patent No. 5038172

However, in the press machine described in Patent Document 1, since the upper die and the movable table are fixed, excessive pressure is applied from the movable table to the work material due to expansion and contraction of the housing due to temperature change, for example. In some cases, the effect of buffering by the buffer hydraulic cylinder is considered to be limited.

In the press device described in Patent Document 2, a moving table provided with the first urging means is fixed to the upper frame. Further, a punch plate and a base base provided with a second coil spring are fixed to the lower frame. During the manufacture of this press device, the parallelism between the moving table and the base is precisely adjusted so that the rod on the moving table side is pressed vertically to the punch plate on the base table side when the upper frame is lowered. There is a need to. Further, when removing the mold structure, it is necessary to remove both the upper frame and the lower frame, and it is not easy to replace the mold structure.

In addition, the servo press, which is effective as a countermeasure against springback, has restrictions such as the machining speed cannot be increased or the required machining force cannot be obtained. Therefore, the application of the servo press is limited, and the productivity may decrease as compared with a normal press processing device.

Furthermore, at present, it is becoming difficult to secure human resources, and there is a shortage of engineers with skills such as die height adjustment and mold correction. In addition, since it is becoming difficult to inherit the technology, it is a big problem in the press industry to change the conventional processing method that depends on the skill of the engineer to the processing method that does not depend on the skill of the engineer.

The present invention has been made in view of such circumstances, and can reduce the influence of unstable positioning accuracy caused by the press machine body in a scene of high-precision machining, and can be used by a skilled engineer for a press working apparatus. It is an object of the present invention to provide a mold structure that does not require adjustment, is excellent in productivity, and is easy to be attached to and detached from the press machine body. Another object of the present invention is to provide a press working apparatus and a press working method using this die structure.

The mold structure of the present invention is a mold structure that is arranged between a movable table and a fixed table of a press machine body to press a work material, and the mold structure is fixed to the fixed table. The lower mold to be formed, the upper mold provided above the lower mold, the first elastic body and the stopper provided between the upper mold and the lower mold, and the movable base side of the upper mold. It is provided with a connected pressure adjusting device, and the pressure adjusting device has a pressure plate abutting on the movable table and a second elastic body provided between the pressure plate and the upper mold. Then, during non-pressurization of the press working, the first elastic body separates the upper mold from the lower mold, and at the time of pressurization, the stopper defines the lower dead point position of the upper mold. The pressure from the movable table is applied from the pressure plate of the pressure adjusting device to the upper mold via the second elastic body to sandwich the work material between the upper mold and the lower mold. It is characterized by.

It is characterized in that the end surface of the upper end of the second elastic body is in non-fixed contact with the lower surface of the pressure plate.

The second elastic body is characterized by being a fluid spring. Further, the fluid spring has a housing, a fluid enclosed inside the housing, and a piston rod that can expand and contract in the axial direction of the housing, and the end surface of the upper end of the piston rod is under pressure. It is characterized in that it abuts on the lower surface of the plate in a non-fixed manner, and a pressure is applied from the pressure plate to the piston rod in the axial direction of the housing.

The mold structure is characterized by having a means for suppressing changes in the speed and acceleration of the upper mold.

The press working apparatus of the present invention includes the mold structure of the present invention, a fixed base on which the lower mold of the mold structure is fixed, and a movable base to which the pressure plate of the mold structure is abutted. It is characterized by being equipped with.

The press working method of the present invention is a press working method for pressing the work material by using the mold structure of the present invention, and after arranging the work material in the lower mold, the first method is performed. The upper die, which is separated from the lower die by an elastic body, receives the pressure of the movable table via the pressure adjusting device, descends, and is positioned at the target bottom dead point position by the stopper. With the mold positioned, the movable table descends to the bottom dead point position of the movable table while compressing the second elastic body of the pressure adjusting device, and the movable table changes to an ascending stroke. Until the compression of the second elastic body is released, the upper die stays at the target lower dead point position, so that the work material is sandwiched between the upper die and the lower die for a predetermined time and pressed. It is characterized by processing.
Here, the target bottom dead center position of the upper die means the bottom dead center position of the upper die in which the optimum machining force can be applied to the material to be machined.

The mold structure of the present invention is a mold structure that is arranged between the movable base and the fixed base of the press machine body to press the work material, and is a lower mold fixed to the fixed base and a lower mold. A pressure adjusting device including a first elastic body and a stopper provided between the upper die and the upper die and the lower die, and a pressure adjusting device connected to the movable base side of the upper die. However, it has a pressure plate that is in contact with the movable table and a second elastic body provided between the pressure plate and the upper mold, and the first elastic body is the upper mold during non-pressurization of press working. When pressurizing, the pressure from the movable table is applied from the pressure plate of the pressure regulator to the upper mold via the second elastic body while the stopper defines the lower dead point position of the upper mold. Since the work material is sandwiched between the upper mold and the lower mold, the pressure adjustment device adjusts the position of the lower dead point of the movable table while positioning the lower dead point position of the upper mold with high accuracy. Can be absorbed. Therefore, the influence of unstable positioning accuracy caused by the press machine body can be reduced, and high-precision machining can be performed. Further, since the pressure adjusting device is contained in the mold structure, it can be easily attached to and detached from the press machine body. These eliminate the need for skilled technicians to adjust the press working equipment, which is required in the case of conventional press working equipment. Furthermore, compared to the conventional press working device, even if the time for the movable table to move up and down once is shorter, the time to stay at the bottom dead center position of the upper die (hereinafter referred to as "bottom dead center time") is longer. Since it can be kept for a long time, it is possible to significantly reduce the springback without reducing the machining speed and machining force unlike the servo press, and it is excellent in productivity. In addition, the crushing stability of the material in the plate thickness direction is improved.

Since the end face of the upper end of the second elastic body is in non-fixed contact with the lower surface of the pressure plate, the force in the thrust direction is transmitted to the second elastic body even when the pressure plate is slightly displaced. It is difficult and can prevent distortion of the second elastic body.

Since the second elastic body is a fluid spring, it is superior in the property of attenuating the vibration caused by the press machine body, and the influence of unstable positioning accuracy caused by the press machine body can be further reduced.

Further, the fluid spring has a housing, a fluid enclosed inside the housing, and a piston rod that can expand and contract in the axial direction of the housing, and the end surface of the upper end of the piston rod is not on the lower surface of the pressure plate. Since the contact is fixed and pressure is applied from the pressure plate to the piston rod in the axial direction (vertical vertical direction) of the housing, even if the pressure plate is slightly displaced, the piston rod is in the thrust direction. It is difficult to transmit the force of the fluid spring, and it is possible to prevent the internal fluid of the fluid spring from leaking to the outside due to the tilt of the piston rod. As a result, it is possible to prevent the performance of the pressure regulator from deteriorating.

Since the die structure has a means for suppressing changes in the speed and acceleration of the upper die, the sudden decrease in the repulsive force from the work piece during punching is damped, and the high acceleration movement of the upper die is suppressed. It is possible to suppress the end of the stopper at high acceleration. As a result, noise during press working can be reduced.

The press working apparatus of the present invention includes the above-mentioned mold structure of the present invention, a fixed base to which the lower mold of the mold structure is fixed, and a movable base to which the pressure plate of the mold structure is abutted. Therefore, compared to the conventional press processing equipment, it is not necessary for a skilled engineer to adjust the press processing equipment such as a die height, and high-precision processing can be performed regardless of the skill of the engineer.

The press working method of the present invention is a press working method of pressing a work material by using the above-mentioned mold structure of the present invention. The upper die, which is separated from the upper die, receives the pressure of the movable table through the pressure adjustment device, descends, and is positioned at the target bottom dead center position by the stopper. While compressing the second elastic body of the adjusting device, it descends to the bottom dead center position of the movable table, the movable table changes to the ascending stroke, and the upper mold is released until the compression of the second elastic body is released. By staying at the target bottom dead center position, the work material is sandwiched between the upper mold and the lower mold for a predetermined time and pressed, so the bottom dead center time of the upper mold can be lengthened and springback is greatly reduced. can. In addition, the crushing stability of the material in the plate thickness direction is improved. Further, even if the position of the movable table is displaced, the pressure adjusting device can absorb the displacement, so that the influence of unstable positioning accuracy can be reduced and high-precision machining can be performed.

It is a side view of the mold structure (when not pressurized) of this invention. It is a side view of the mold structure (at the time of pressurization) of this invention. It is a top view when the pressure adjusting device is seen from above. It is sectional drawing of the fluid spring which is an example of the 2nd elastic body. It is a perspective view of the connector terminal which was pressed. It is a side view of the mold structure provided with the restraining means. It is a figure which shows the trajectory of the conventional press working apparatus. It is a figure which shows the processing force of the conventional press processing apparatus. It is a figure which shows the trajectory of the press working apparatus of this invention. It is a figure which shows the processing force of the press processing apparatus of this invention.

An example of the mold structure of the present invention will be described with reference to FIGS. 1 and 2. 1 and 2 are side views when the mold structure of the present invention is viewed from the side surface orthogonal to the traveling direction of the material to be processed, FIG. 1 shows a state when no pressure is applied, and FIG. 2 shows an addition. The state at the time of compression is shown respectively.
As shown in FIGS. 1 and 2, the mold structure 1 includes a lower mold 3 fixed to a fixing base 2, an upper mold 4 provided above the lower mold 3, and an upper mold 4 and a lower mold 3. It is provided with a first elastic body 11 and a stopper 10 provided between the two, and a pressure adjusting device 6 connected to the movable table 5 side of the upper die 4. Here, the fixed base 2 and the movable base 5 are not included in the configuration of the mold structure of the present invention, and are a part of the press working apparatus to which the mold structure 1 is attached.

When the press working shown in FIG. 1 is not pressurized, the first elastic body 11 separates the upper mold 4 and the lower mold 3, and when the pressing work shown in FIG. 2 is pressed, the stopper 10 is the upper mold 4. While defining the bottom dead center position, the pressure from the movable table 5 is applied from the pressure plate 7 of the pressure adjusting device 6 to the upper die 4 via the second elastic body 8, and the work material 30 is moved to the upper die 4 and the lower die 4. It is sandwiched between the mold 3 and pressed.

The lower mold 3 includes a metal plate 3a that supports the work material 30 and a metal plate 3b that is fixed to the fixing base 2. The metal plate 3a is a die plate and the metal plate 3b is a backing plate. Further, the upper mold 4 includes a metal plate 4a arranged directly under the pressure adjusting device 6 and a metal plate 4b arranged under the metal plate 4a. The metal plate 4a is a backing plate. The metal plate 4b includes a punch plate and a stripper plate arranged below the punch plate (not shown). A punch 14 that pressurizes the work piece 30 from above is provided on the lower surface of the metal plate 4b. The punch 14 pressurizes the workpiece 30 through the punch holes of the stripper plate. The upper surface of the metal plate 3a is provided with a recess 15 arranged so as to face the punch 14 in the vertical direction. The punch 14 sandwiches the work material 30 between the recess 15 and the work material 30 and pressurizes the punch 14 to give the work material 30 a predetermined shape.

The pressure adjusting device 6 includes a pressure plate 7 that comes into contact with the movable table 5, a second elastic body 8, and a regulating member 13. The second elastic body 8 is arranged between the pressure plate 7 and the upper mold 4. The pressure plate 7 and the movable base 5 are only in contact with each other and are not fixed. In the present invention, since the pressure adjusting device 6 is provided on the upper part of the upper die 4, when the upper die 4 is fixed to the movable table 5, it is necessary to fix the pressure plate 7 of the pressure adjusting device 6 to the movable table 5. .. Due to its structure, it is not easy to fix. Even if the mold structure 1 does not fix the upper mold 4 (pressure plate 7) and the movable base 5, the movable base 5 is formed on the entire upper surface of the pressure plate 7 while fixing the lower mold 3 to the fixed base 2. Since it is in close contact with the lower surface and receives pressure vertically, the position of the mold structure 1 does not shift.

The relationship between the pressure adjusting device 6 and the upper die will be described with reference to FIG. FIG. 3 is a plan view of the pressure adjusting device as viewed from the upper surface of the pressure plate.
As shown in FIG. 3, the side surface of the pressure plate 7 is provided with a regulating member 13 that slidably abuts on the side surface of the upper metal plate 4a arranged below the pressure plate 7. The regulating member 13 is provided on all four side surfaces of the pressure plate 7 which constitutes a quadrangle when viewed from above. The pressure plate 7 and the metal plate 4a have the same shape when viewed from above. Each of the four regulating members 13 comes into contact with the four side surfaces of the upper die 4 without a gap, so that the displacement of the horizontal positional relationship between the pressure adjusting device 6 and the upper die 4 can be prevented. As a result, the lower surface of the pressure plate 7 and the upper surface of the metal plate 4a repeatedly approach and separate only in the vertical direction, so that the pressure from the pressure plate 7 is applied to the upper surface of the metal plate 4a via the second elastic body 8. It hangs perpendicular to. In addition to the above-mentioned regulating member, the regulating member may not necessarily be provided as long as it can be regulated so that the horizontal positional relationship between the pressure adjusting device and the upper die is kept constant by a method such as a guide.

In FIG. 3, 11 second elastic bodies 8 (indicated by dotted lines) are provided at predetermined intervals in order to evenly apply the pressure received from the movable table to the entire upper surface of the upper die. Here, the upper surface of the upper mold means the upper surface of the metal plate 4a in FIG. In FIG. 3, the pressure plate 7 and the upper surface of the upper mold are restricted from moving in the horizontal direction as described above. On the other hand, the pressure plate 7 and the upper mold are not fixed by the second elastic body in the vertical direction. Therefore, the pressure plate 7 is connected by a plurality of disconnection prevention portions 16 so as to be movable in the vertical direction with respect to the upper mold but not to be disengaged. The pull-out prevention portion 16 is provided so that the vertical distance between the lower surface of the pressure plate 7 and the upper surface of the upper die is maintained within a predetermined range. As a result, the lower surface of the pressure plate 7 and the upper surface of the upper mold can be brought close to each other and separated from each other while remaining parallel. Further, the insertion member 12c penetrates the pressure plate 7 in the vertical direction and is provided at four places at predetermined intervals, and the horizontal movement of the mold structure is regulated by the guide rod.

The structure of the fluid spring used as the second elastic body will be described with reference to FIG. FIG. 4 is a cross-sectional view of a fluid spring which is an example of the second elastic body.
As shown in FIG. 4, the second elastic body 8'has a housing 18, a fluid 19 sealed inside the housing 18, and a piston rod 17 that can expand and contract in the axial direction (XY direction) of the housing 18. Is a spring that utilizes the elasticity of the fluid 19. By using the fluid spring for the second elastic body, the vibration caused by the press machine body can be attenuated, so that the influence of the unstable positioning accuracy caused by the press machine body can be reduced.

The second elastic body is not limited to the fluid spring, but can be selected from various elastic bodies such as metal springs and rubber springs. The optimum spring can be selected according to the member cost, required characteristics, and the like, and the fluid spring is preferably used as the second elastic body because it is excellent in the above-mentioned damping characteristics. The fluid of the fluid spring can be selected from, for example, oil, air, nitrogen and the like. Further, in the present invention, since it is necessary to use an elastic body having a high spring constant as the second elastic body, it is preferable to select a fluid in which high-pressure nitrogen gas or the like is enclosed. Further, the number and the arrangement location of the second elastic body can be appropriately set, and the configuration is not limited to that shown in FIG.

The mode of installing the second elastic body will be described with reference to FIG. The end face of the upper end of the second elastic body 8 is in contact with the lower surface of the pressure plate 7. In particular, it is preferable that the end surface of the upper end of the second elastic body 8 and the lower surface of the pressure plate 7 are not fixed without being fixed with bolts or the like. In the case of a fluid spring as shown in FIG. 4, the end surface of the upper end of the piston rod abuts on the lower surface of the pressure plate 7 in a non-fixed manner, and pressure is applied from the pressure plate 7 to the piston rod in the axial direction of the housing. Can be configured. A recess is provided on the upper surface of the upper die 4, and the upper die 4 and the second elastic body 8 are positioned by fitting the lower end of the second elastic body 8 into the recess. Here, the lower end of the second elastic body may be firmly fixed or may be loosely fitted only. For positioning, a recess may be provided on the lower surface of the pressure plate, and the upper end of the second elastic body may be fitted with a gap in the recess.

The horizontal positional relationship between the pressure plate and the upper mold of the pressure regulator is regulated by regulatory members so that it remains constant, but slight deviations may occur. Therefore, with the above configuration (non-fixed), it is difficult for the force in the thrust direction to be transmitted to the piston rod of the second elastic body, and the pressure applied to the second elastic body from the pressure plate is the pressure of the second elastic body. It hangs only in the vertical direction (vertical direction) along the long axis. As a result, distortion of the second elastic body can be prevented. In particular, when the second elastic body is a fluid spring, it is possible to prevent the internal fluid of the fluid spring from leaking to the outside due to the inclination of the piston rod or the like. As a result, the performance of the pressure adjusting device can be easily maintained, and the influence of unstable positioning accuracy caused by the press machine body can be reduced for a long period of time. Further, since the second elastic body is not fixed to the pressure plate and the upper mold, the second elastic body can be easily replaced, so that the time and labor at the time of design change can be reduced.

A first elastic body 11 and a stopper 10 are provided between the upper mold 4 and the lower mold 3. The stopper 10 defines the bottom dead center position of the upper die 4 at the time of pressurization. The stopper 10 includes an upper stopper 10a and a lower stopper 10b provided at a position where the stopper 10 abuts. The upper stopper 10a is provided on the lower surface of the metal plate 4a of the upper mold 4, and the lower stopper 10b is provided on the upper surface of the metal plate 3b of the lower mold 3. The number and location of stoppers (a pair of upper and lower parts) can be set as appropriate, and is not limited to the configuration shown in FIG.

The first elastic body 11 is provided to separate the upper mold 4 and the lower mold 3 when the pressure is not applied, and a metal coil spring is used. When the mold structure is viewed from above, the first elastic bodies 11 are provided at predetermined intervals along the outer peripheral portion of the mold structure, and a total of eight first elastic bodies 11 are provided (not shown). The spring constant of the second elastic body 8 is larger than the spring constant of the first elastic body 11. After pressurizing the work piece 30, the first elastic body 11 lifts both the upper die 4 and the pressure adjusting device 6 when the movable table 5 rises from the bottom dead center. At that time, the upper surface of the pressure plate 7 and the lower surface of the movable base 5 are not separated from each other.

The first elastic body can be selected from metal springs, fluid springs, rubber springs, and the like as long as it is an elastic body. As the first elastic body, it is preferable to use a metal coil spring which is excellent in cost and can secure a large amount of deformation. Further, the number and the arrangement location of the first elastic body 11 can be appropriately set, and the configuration is not limited to that shown in FIG.

As shown in FIGS. 1 and 2, in the press working apparatus provided with the mold structure 1 of the present invention, pressure is also applied to the upper mold 4 via the pressure plate 7 by lowering the movable table 5, and the upper mold 4 is subjected to pressure. Go down. The amount of deformation of the first elastic body 11 at that time is larger than the amount of deformation of the second elastic body 8. When the upper mold 4 descends and approaches the lower mold 3, the upper stopper 10a and the lower stopper 10b abut each other, and the upper mold 4 reaches the target bottom dead center position by the stopper whose length is adjusted in advance. The movable table 5 descends further, while the upper die 4 stays at its target bottom dead center position. The movable table 5 deforms only the second elastic body 8 and descends to the bottom dead center position of the movable table 5 while displacing the pressure adjusting device 6 downward.

While the movable table 5 is descending, the upper mold 4 continues to receive the pressure from the movable table 5 via the pressure plate 7. While the upper die 4 stays at the target bottom dead center position due to the repulsive force from the stopper 10, the second elastic body 8 absorbs the pressure received from the movable table 5 and deforms from the movable table 5. The pressure applied to the stopper 10 can be reduced. After that, the movable base 5 starts to rise, the compression of the second elastic body 8 is released, the upper stopper 10a and the lower stopper 10b are separated from each other, and at the same time, the upper die 4 also rises from the target bottom dead center position. By operating in this way, the stopper 10 does not receive a force equal to or higher than a predetermined pressure from the movable table 5, and is not easily damaged or deformed even if it is repeatedly pressed. As a result, the bottom dead center position of the upper die 4 can be defined as the target position for a longer period of time, so that the quality of the product tends to be within the target error range.

The pressure adjusting device 6, the upper mold 4, and the lower mold 3 are connected by a guide 12. The guide 12 is composed of a guide rod 12a, an insertion member 12b, and an insertion member 12c. The guide rod 12a is provided so as to penetrate the three members of the pressure plate 7, the metal plate 4a, and the metal plate 3b. The pressure plate 7 is provided with an insertion member 12c having an insertion hole through which the guide rod 12a is inserted. Further, the metal plate 4a is provided with an insertion member 12b having an insertion hole through which the guide rod 12a is inserted. Here, the inner surface of each insertion member and the outer surface of the guide rod 12a are slidably in contact with each other. As a result, the pressure adjusting device 6 can be slidably displaced in the vertical direction along the guide rod 12a. Similarly, the upper die 4 can be slidably displaced in the vertical direction along the guide rod 12a.

The mold structure may be further provided with means for suppressing changes in the speed and acceleration of the upper mold. The means for suppressing changes in the speed and acceleration of the upper die is referred to as a suppressing means. As an example of the mold structure provided with the suppressing means, FIG. 6 shows a mold structure having a pressure adjusting device provided with the suppressing means. As shown in FIG. 6, in the mold structure 1', the pressure adjusting device 6'includes a pressure plate 7, a second elastic body 8, a suppressing means 9, and a regulating member 13. A plurality of suppressing means 9 are arranged between the pressure plate 7 and the upper mold 4 at predetermined intervals. An oil damper is used as the suppressing means 9.

When an oil damper is used as the suppressing means, the fixing method can be the same as that of the second elastic body 8 described above. Similar to the second elastic body, by making the end face of the suppressing means 9 and the pressure plate 7 non-fixed, a thrust load is not applied to the suppressing means, so that uneven wear between the members of the suppressing means inside the suppressing means is caused. It is suppressed. Suppression of uneven wear leads to reduction of oil leakage from the suppressing means and maintenance of performance of the pressure regulator.

The second elastic body of the pressure regulator uses an elastic body with a spring constant larger than that of the first elastic body. If the die structure is not provided with restraining means, the repulsive force from the work piece sharply decreases during punching, and the downward pressure from the pressure regulator generates a large acceleration in the upper die. , The upper stopper and the lower stopper hit. The end force generated here may affect noise, product accuracy, maintenance life, and the like. Therefore, it is preferable to use the suppressing means because it suppresses changes in the speed and acceleration of the upper die during punching and suppresses the abutting of the stopper at high acceleration.

As for the suppression performance, which is the ability to suppress changes in the speed and acceleration of the upper mold, the higher the performance, the more sudden changes in the speed and acceleration of the upper mold can be suppressed, but if it is too high, excessive pressure will be generated. Therefore, the spring constant of the second elastic body, the number of second elastic bodies, the type and number of restraining means, and their It is necessary to comprehensively consider the positional relationship. It should be noted that the above problem may be solved by using a type of the second elastic body, a different type of elastic body, or the like without using the suppressing means.

The type of suppression means is not limited to oil dampers, but can be freely selected, including metal dampers and rubber dampers. Further, the place where the suppressing means is provided is not limited to between the pressure plate and the upper mold, but may be provided between the upper mold itself or between the upper mold and the lower mold, and can be freely selected. When the suppressing means is provided between the upper mold and the lower mold, for example, the suppressing means may be provided between the upper mold and the lower mold so as to be parallel to the first elastic body, as in the case of the first elastic body. , The first elastic body and the restraining means may be provided so as to be connected in series in the vertical direction between the upper mold and the lower mold. When the suppressing means is provided between the upper mold and the lower mold, the speed and acceleration of the upper mold can be directly suppressed because the downward movement of the upper mold is resisted.

As a suppressing means, a metal plate for a weight may be provided on the upper mold to increase the mass of the upper mold. The metal plate for the weight may be provided exclusively for increasing the mass, or the backing plate, punch plate, or the like may be increased in mass to have the function of the metal plate for the weight. Since the inertial force is proportional to the mass, increasing the mass of the upper mold has the effect of suppressing changes in the velocity and acceleration of the upper mold. The type of metal of the metal plate for the weight can be freely selected from, for example, lead, brass, tungsten, iron, stainless steel, and the like. A metal plate made of tungsten is preferable because the high specific density of tungsten makes it possible to improve the suppression performance and reduce the size of the mold structure at the same time. On the other hand, a lead metal plate has a relatively high specific gravity and is inexpensive as a raw material price, and is preferable because it has an excellent balance between suppression performance and price. In this way, by providing the metal plate for the weight, changes in the speed and acceleration of the upper die can be easily suppressed, and noise, product accuracy, and maintenance life can be improved.

The method of attaching the mold structure of the present invention to the press machine will be described below. When attaching the die structure to the press machine, place only the lower die of the die structure on the fixing table of the press machine, and fix it with bolts so that the lower surface of the lower die is parallel to the upper surface of the fixing table. .. At that time, the pressure adjusting device may not be fixed to the movable table and may be separated from the movable table. Next, the height of the movable table is adjusted so that the upper surface of the pressure plate and the lower surface of the movable table come into contact with each other at the top dead center position of the movable table. Here, the top dead center means the time when the distance between the movable table and the fixed table is the farthest in the vertical movement, and the top dead center position means the position at the top dead center. The height of the movable table is adjusted by adjusting the height adjusting portion of the movable table provided in the press machine.

By abutting the upper surface of the pressure plate and the lower surface of the movable table at the top dead center position of the movable table, the upper surface of the pressure plate and the lower surface of the movable table are in contact with each other while the movable table moves up and down. Is maintained. As a result, when the movable table is lowered, the movable table does not collide with the pressure plate, and problems such as vibration, noise generation, and energy loss can be prevented. Further, the adjustment for bringing the upper surface of the pressure plate into contact with the lower surface of the movable table at the top dead center of the movable table is an adjustment only for bringing the respective surfaces into contact with each other. Since it is not a die height adjustment for positioning the upper and lower molds, the mold structure can be easily replaced even by a non-skilled technician.

The method of positioning the upper mold and the lower mold in the mold structure of the present invention will be described below. Positioning of the upper mold and lower mold, that is, the definition of the target bottom dead center position of the upper mold is performed by adjusting the length of the stopper. Specifically, the length of the stopper when the upper stopper and the lower stopper are in contact with each other is adjusted so that the upper die stops at the target bottom dead center position when the movable table of the press machine is lowered. The length of the stopper can be easily adjusted by an ordinary technician by using a contact-type length measuring device, a non-contact type optical shape measuring device, or the like. The ability to easily position without having to adjust the die height by a skilled technician can lead to securing technicians and solving problems in technology transfer.

In the mold structure of the present invention, a first elastic body and a stopper are provided between the lower mold and the upper mold, and a pressure adjusting device is provided above the upper mold. Further, the press working apparatus provided with the mold structure of the present invention is a press working apparatus provided with a mold structure, a fixed base for fixing the mold structure, and a movable base which can move in the vertical direction with respect to the fixed base. The effect of such a configuration will be described below with reference to FIGS. 7 to 10 in comparison with the conventional press working apparatus.

FIG. 7 shows the track of the movable table of the conventional press working device and the track of the upper die. The trajectory of the movable table means a change in the position of the movable table with time in a single vertical motion of descending and ascending to press the work material. Similarly, the orbit of the upper mold means the change of the position of the upper mold with time. Here, the solid line represents the target trajectory that is the target trajectory passing through the target bottom dead center position, and the dotted line is the trajectory in which the actual bottom dead center position is changed below the target bottom dead center position. Represents an orbit.

In a conventional press working device, the upper die is fixed to a movable table and the lower die is fixed to a fixed table, and the movable table is lowered so that the upper die and the lower die add a work material placed between them. Processing is performed by pressing and transferring the mold shape to the work material. The pressure received by the work material, that is, the work force, is determined not only by the strength of the force of the press device but also by the positional relationship between the upper die, the lower die, and the work material. Therefore, in the conventional press working apparatus, the position of the upper die is affected by the position of the movable table which is fixed. In the case of bending, the work material begins to receive processing force from the time when the upper mold begins to deform the work material, and the work force reaches the bottom dead center of the movable table, that is, until the upper mold reaches bottom dead center. Continues to increase. At bottom dead center, the maximum processing force is applied to the material to be processed.

In the conventional press working equipment, the upper die is fixed to the movable table, so when the trajectory of the movable table changes, the trajectory of the upper die also displaces the changed trajectory deviated from the target trajectory. Changes in the trajectory of the movable table are caused by wear in the mechanism that drives the movable table, backlash of sliding parts, environmental temperature, and expansion and contraction of the housing due to temperature changes generated by the press machine itself. For example, if the housing expands slightly due to a temperature rise, the trajectory of the movable table shifts below the target trajectory. In that case, the upper die orbit fixed to the movable table also shifts downward from the target orbit, and the lower dead center of the upper die changes to a position lower than the target lower dead center position (see FIG. 7).

FIG. 8 shows the change with respect to the time of the processing force received by the work material from the time when the movable table of the conventional press working equipment descends to press the work material and then rises. Here, the solid line represents the change in machining force with respect to time when the movable table moves on the target trajectory, and the dotted line represents the change in machining force with respect to time when the movable table moves on the changing trajectory shifted downward.

When the bottom dead center position of the upper mold deviates from the target bottom dead center position, various problems occur. For example, when the bottom dead center position of the upper die changes above the target bottom dead center position, the force applied to the work material is small, and the processing may be insufficient. On the other hand, when the bottom dead center position of the upper die changes below the target bottom dead center position, a machining force that is excessive compared to the target machining force is applied to the work material and the mold, so the work material is processed. In addition to deterioration of accuracy and material breakage, it may lead to damage to the mold (see FIG. 8). Therefore, in order to perform stable and highly accurate press working, even if the trajectory of the movable table changes for some reason, the bottom dead center position of the upper die hardly changes from the target bottom dead center position, which is an allowable range. It is desirable to be controlled within. The

It is also important to apply the target machining force to the work material for a predetermined time in order to perform stable and highly accurate press working. If the target machining force load time, which is the time for applying the target machining force to the work material, changes, it causes variations in product quality. Therefore, it is necessary to keep not only the bottom dead center position of the upper die but also the target machining force load time constant so that it does not change. Further, in order to reduce springback and the like, it is generally preferable to lengthen the target machining force load time.

For the above reasons, in the conventional press working equipment, in order to control the bottom dead center position of the upper die and generate the optimum machining force for machining, a skilled technician adjusts the die height to position the bottom dead center. Will be done. Specifically, after attaching the die to the press machine, the die height is adjusted so that the distance between the upper mold and the lower mold when the movable table is lowered to the bottom dead center position becomes a predetermined distance. Further, in the conventional press working apparatus, when the upper die and the lower die come into contact with each other at the bottom dead center, a problem such as damage to the die occurs. Therefore, a stopper is provided for the purpose of protecting the die. Actually, the upper die and the lower die are pressed under the condition that they do not come into contact with each other by adjusting the die height, so the stopper works to prevent the upper die and the lower die from coming into contact with each other. Only when it is misaligned.

FIG. 9 shows the track of the movable table of the press working apparatus provided with the mold structure of the present invention and the track of the upper die. The meanings of the orbit of the movable table, the orbit of the upper die, the target orbit, and the change orbit are the same as those in FIG.

FIG. 10 shows a change with respect to the time of the processing force received by the work material from the time when the movable table of the press working apparatus provided with the mold structure of the present invention descends to press the work material and then rises. .. Similar to FIG. 8, the solid line represents the change in machining force over time when the movable table moves on the target trajectory, and the dotted line represents the change in machining force over time when the movable table moves on the changing trajectory.

In the mold structure of the present invention, the stopper is provided not for the purpose of protecting the mold but for the purpose of positioning the bottom dead center of the upper mold. When not pressurized, the upper mold is lifted by a first elastic body placed between it and the lower mold (see FIG. 1). As the pedestal descends, the pedestal pushes down on the pressure regulator and the upper mold. The pushed-down upper mold is positioned at the target bottom dead center position when the lower end of the upper stopper and the upper end of the lower stopper meet (see FIGS. 2 and 9).

Even after the upper stopper and the lower stopper hit each other, the movable table descends to the bottom dead center position of the movable table while compressing the second elastic body of the pressure adjusting device. The movable platform then changes to an ascending stroke. The upper die stays at the target bottom dead center position of the upper die until the movable base changes to the ascending stroke and the upper stopper and the lower stopper are separated from each other. As a result, the bottom dead center position of the upper die is defined by the stopper at the target bottom dead center position, so even if the bottom dead center position of the movable table changes, such as when the bottom dead center position shifts downward, the pressure regulator absorbs the change. , Excessive pressure is not applied to the stopper (see FIG. 10).

In the conventional press processing device, the bottom dead center position of the upper die is adjusted by adjusting the die height of the movable table, whereas in the mold structure of the present invention, the upper stopper and the lower stopper abut and the bottom dead center of the upper die is reached. Since the position is specified, die height adjustment is not required. This contributes to securing skilled engineers and solving problems in technology transfer. By using the mold structure of the present invention, it is possible to control the deviation from the target bottom dead center position of the upper mold within several tens of μm without adjusting the die height.

In addition, the conventional press processing device applies the target processing force only at the moment when the movable table reaches the bottom dead center position (see FIG. 8). On the other hand, the press working apparatus provided with the mold structure of the present invention is above for a certain period of time before and after the movable table reaches the bottom dead center position, that is, during the stay at the target bottom dead center position of the upper die. The mold continues to load the target machining force on the work piece (see FIG. 10). The press working apparatus provided with the mold structure of the present invention can keep the bottom dead center time of the upper die longer, so that the target machining force load time can be made longer. As a result, it is possible to significantly reduce the springback without reducing the machining speed unlike the servo press, and the productivity is excellent. In the case of a conventional press working apparatus, the bottom dead center time of the upper die is about several milliseconds to several tens of milliseconds. On the other hand, when the mold structure of the present invention is used, the bottom dead center time of the upper mold can be lengthened.

In the case of progressive press processing, each metal member slides at high speed and repeatedly collides, so compared to a single press, the vibration of the press machine and the expansion of the heat-generating housing cause the bottom dead center position of the movable table. Misalignment is likely to occur. Therefore, the mold structure of the present invention, which can reduce the influence of unstable positioning accuracy caused by the press machine body, can be particularly preferably used for the use of progressive press processing.

An example of a processed product produced by pressing a work material by the press processing apparatus of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of a connector terminal manufactured by continuously shearing or bending a copper plate as a work material. As shown in FIG. 5, the connector terminal 40 has a plurality of bent portions and punched portions. The length of the long side of the connector terminal 40 is 30 mm, the thickness of the metal plate is 0.5 mm, and the width of the terminal tip is 2.3 mm.

In the press working method and the press working apparatus of the present invention, as described above, the target machining force load time on the work piece can be made longer and the springback can be significantly reduced, so that such a processed product can also be highly accurate. Can be processed with high productivity.

The mold structure of the present invention can reduce the influence of unstable positioning accuracy caused by the press machine body, does not require adjustment of the press processing device by a skilled engineer, is excellent in productivity, and can be applied to the press machine body. Since it is easy to install and remove, it can be used for processing various metal parts used in electronic devices and automobiles.

1, 1'Mold structure 2 Fixed base 3 Lower mold 3a, 3b Metal plate 4 Upper mold 4a, 4b Metal plate 5 Movable base 6, 6'Pressure regulator 7 Pressure plate 8, 8'Second elastic body 9 Suppressing means 10 Stopper 10a Upper stopper 10b Lower stopper 11 First elastic body 12 Guide 12a Guide rod 12b, 12c Insertion member 13 Restriction member 14 Punch 15 Recession 16 Detachment prevention part 17 Piston rod 18 Housing 19 Fluid 30 Work material 40 Connector terminal

Claims

It is a die structure that is placed between the movable table and the fixed table of the press machine body to press the work material.
The mold structure includes a lower mold fixed to the fixing base, an upper mold provided above the lower mold, and a first elastic body and a stopper provided between the upper mold and the lower mold. And a pressure adjusting device connected to the movable table side of the upper die.
The pressure adjusting device has a pressure plate abutting on the movable table and a second elastic body provided between the pressure plate and the upper mold.
The first elastic body separates the upper die from the lower die during non-pressurization of the press working, and the stopper defines the bottom dead center position of the upper die during pressurization. It is characterized in that the pressure from the movable table is applied from the pressure plate of the pressure adjusting device to the upper die via the second elastic body to sandwich the work material between the upper die and the lower die. Mold structure.
The mold structure according to claim 1, wherein the end surface of the upper end of the second elastic body is in non-fixed contact with the lower surface of the pressure plate.
The mold structure according to claim 1, wherein the second elastic body is a fluid spring.
The fluid spring has a housing, a fluid enclosed inside the housing, and a piston rod that can expand and contract in the axial direction of the housing.
3. The third aspect of the present invention is that the end surface of the upper end of the piston rod abuts on the lower surface of the pressure plate in a non-fixed manner, and pressure is applied from the pressure plate to the piston rod in the axial direction of the housing. The described mold structure.
The mold structure according to claim 1, wherein the mold structure has means for suppressing changes in the speed and acceleration of the upper mold.
The mold structure according to claim 1, characterized by comprising a fixed base to which the lower mold of the mold structure is fixed, and a movable base to which the pressure plate of the mold structure is abutted. Press processing equipment.
A press working method for pressing the work material by using the mold structure according to claim 1.
After arranging the work material in the lower mold, the upper mold in a state of being separated from the lower mold by the first elastic body receives the pressure of the movable table via the pressure adjusting device and descends. The stopper is positioned at the target bottom dead center position.
With the upper mold positioned, the movable table descends to the bottom dead center position of the movable table while compressing the second elastic body of the pressure adjusting device.
The upper mold stays at the target bottom dead center position until the movable table changes to the ascending stroke and the compression of the second elastic body is released.
A press working method characterized in that the work material is sandwiched between the upper mold and the lower mold for a predetermined time and press working.