JP3859097B2 - Pressing mold with horizontal stripper pressure mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press working mold with a horizontal stripper pressure mechanism used when punching a lead frame for a multi-pin semiconductor package or the like from a workpiece.
[0002]
[Prior art]
Conventionally, a general semiconductor package is manufactured by bonding a semiconductor integrated circuit or the like to a lead frame and molding it with a resin. For punching the lead frame, a working die attached to a press device is used. As shown in FIG. 5, this press working mold 1 includes upper and lower molds 2 and 3, and a punch 4 is installed in the upper mold 2 in order to punch out a lead frame from a workpiece, and the lower mold 3 A die 5 that hits the punch is installed. Further, in order to operate the punch 4 in the upper die 2, a backing plate 7 and a punch plate 8 are installed on the lower side of the upper die set 6, and a stripper 10 and a punch guide 11 are connected via a suspension bolt 9. Install.
[0003]
The upper mold 2 is provided with a stripper pressurizing mechanism 12 for pressing the workpiece. The stripper pressurizing mechanism 12 includes a compression coil spring 13 for pressurizing the stripper built in the upper die set 6 and a push rod 14 which is a vertical motion member for transmitting a pressurizing force installed below the spring 13. In addition, the stripper pressurizing spring 13 is accommodated in the vertical hole 15 formed in the thickness direction of the upper die set 6, and the center line of the spring 13 is arranged in the vertical direction. Then, the pressurizing direction of the spring 13 becomes the vertical direction and coincides with the moving direction of the push rod 14. Therefore, the spring force urging below the stripper pressurizing spring 13 is received by the head 16 of the push rod 14, and the pressure generated by the spring 13 is transmitted to the stripper 10 as it is, so that the workpiece (not shown) is transferred. It can be used as a pressing force. Reference numeral 17 denotes a headless screw for adjusting the pressurizing force installed in the spring housing hole 15 and is in contact with the upper end of the stripper pressurizing spring 13.
[0004]
In the lower mold 3, a die holder 19 that supports the die 5 is installed on the lower die set 18, and a guide member 20 that guides the movement of the workpiece is installed on the die holder 19 and the like. . In addition, 21 is a communication hole for dropping a punched chip provided in the die 5, the lower die set 18, the die holder 19, etc., and 22 is a moving direction of the upper mold 2 with respect to the lower mold 3. A main guide post for determining (pressing direction) 23 is a sub guide post.
[0005]
[Problems to be solved by the invention]
However, such an upper die set 6 is necessary in terms of strength because the stripper pressurizing spring 13, the vicinity of the head 16 of the push rod 14, the pressure adjusting headless screw 17, etc. are disposed in the vertical direction and stored. It has the above thickness, and there is a problem that the weight is heavy. The reason is that if the press mold 1 has a heavy upper mold 2, (1) the inertia is increased, the position of the bottom dead center of the press is not stable, and (2) the press power is lost. This is because problems such as (3) resulting in a decrease in work ability cannot be achieved. Therefore, it is desirable that the upper die 2 is light, and the thinner the upper die set 6 is, the better the strength and function are satisfied.
[0006]
Therefore, in order not to make the upper die set 6 too thick, a stripper pressing spring 13 having a short overall length is used. Then, since a large deflection cannot be obtained, a hard spring having a large spring constant must be used. Therefore, it is difficult to finely adjust the pressure applied to the spring 13. Moreover, the spring 13 is tightened from the upper surface of the upper die set 6 by the pressure adjusting headless screw 17, but a movable platen is installed on the upper die set 6. Therefore, there is a problem that the pressure cannot be adjusted by operating the headless screw 17 unless the working die 1 is removed from the press device.
[0007]
The present invention has been made paying attention to such a conventional problem, and is a horizontal stripper pressurizing mechanism which can make the upper die set thinner to make the upper mold lighter and can use a stripper pressurizing spring having a long overall length. An object is to provide a press working die.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the press working mold with a horizontal stripper pressurizing mechanism according to the present invention, a spring for stripper pressurization to the upper mold and the pressurizing force generated by the spring are transmitted to the stripper. A stripper pressurizing mechanism for pressing a workpiece provided with the vertical motion member is installed, and the stripper pressurizing spring is housed in a hole provided in the upper die set. At that time, a spring accommodation hole having a certain depth is formed by drilling from the side surface in the central portion in the thickness direction of the upper die set. A stripper pressurizing spring is arranged in the hole so that the pressurizing direction with respect to the spring is horizontal, and the pressurizing force generated by the spring between the stripper pressurizing spring and the vertical motion member for transmitting the pressurizing force. As a pressurizing direction conversion transmitting means for transmitting by changing the direction, a peristaltic cam that can rotate around an axis is installed.
[0009]
Moreover, it is preferable to install the peristaltic cam in an upper die set or a cam storage chamber provided with an inner wall that regulates the rotation direction of a cam holder built in the upper die set.
[0010]
Also, one force point of the swing cam is in contact with the tappet attached to one end of the stripper pressurizing spring, and the other force point of the swing cam is in contact with one end of the vertical motion member for applying pressure, the swing cam It is preferable that the distance between the center of rotation and the force point in contact with the tappet is larger than the distance between the center of rotation of the swing cam and the force point in contact with the vertical movement member for transmitting pressure.
Further, a pressure adjusting screw that contacts the outer end of the spring may be installed in the spring accommodating hole for stripper pressurization.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a longitudinal sectional view showing a structure in the vicinity of a stripper pressurizing spring when a press working mold with a horizontal stripper pressurizing mechanism to which the present invention is applied is not pressed. The basic structure of this press working die is also substantially the same as that of the conventional press working die 1. However, in order to make the stripper pressurization mechanism 24 horizontal, the arrangement direction of the compression coil spring 25 for stripper pressurization is made different. The center line 26 of the conventional stripper pressing spring 13 is arranged in the vertical direction, whereas the center line 26 of the stripper pressing spring 25 is arranged in the horizontal direction.
[0012]
Therefore, a spring accommodating hole 28 having a certain depth from the side surface is formed in the central portion in the thickness direction of the upper die set 27 arranged in the horizontal direction, and a stripper pressurizing spring 25 is formed at a predetermined position of the spring accommodating hole 28. Storing. However, a tappet 29 that can slide freely inside the spring housing hole 28 is fixed to the end of the spring housing hole 28 before it is housed in the spring housing hole 28 before being attached to the spring housing hole 28. Keep it. Then, a headless screw 30 for adjusting the pressurizing force that contacts the outer end of the stripper pressurizing spring 25 is installed on the inlet side of the spring housing hole 28. An extension 31 is provided on the inlet side of the spring housing hole 28 to facilitate the insertion of the stripper pressurizing spring 25, the screwing operation of the pressure adjusting screw 30, and the like. Further, a female side screw portion 32 for screwing the pressure adjusting screw 30 is provided on the back side of the extended portion 31 up to the vicinity of the center portion of the spring housing hole 28.
[0013]
Further, the upper die set 27 is provided with a cam holder installation hole 33 at a lower position adjacent to the back side of the spring storage hole 28, and a cam holder 36 having a cam storage chamber 35 is fixed thereto using a tap 34. A part 37 of the cam holder 36 is slightly inserted into the spring housing hole 28 in advance. The insertion portion 37 serves as a stopper for the spring 25. Then, a swing cam 38 having a shape obtained by cutting the disk into approximately one-fourth is installed in the cam storage chamber 35 so as to be rotatable in the direction of the arrow. The cam storage chamber 35 includes an inner wall 39 having an arcuate curved surface that regulates the rotation direction of the swing cam 38, so that the swing cam 38 swings around the shaft position 40 without providing a special shaft. The cam 38 can be smoothly rotated. It should be noted that the shaft of the swing cam 38 may actually be provided at the shaft position 40 regardless of the presence or absence of the inner wall 39 that restricts the rotation direction.
[0014]
Then, a push rod 42 penetrating the backing plate 41 is installed as a vertical motion member for transmitting pressure under the swing cam 38 installed on the upper die set 27 in the same manner as in the prior art. However, the push rod 42 is a cylindrical body having the same diameter and does not have an extended head. 2 is a plan view of the vicinity of the cam holder 36 of the upper die set 27, and shows the positional relationship among the tap 34, the swing cam 38, the push rod 42, and the like.
[0015]
In this way, the swing cam 38 is installed between the stripper pressurizing spring 25 and the push rod 42, and the swing cam 38 has a power point on both surfaces orthogonal to the spring 25 and the push rod 42. Protrusions 43 and 44 are provided respectively. Then, the swing cam 38 is made to act as a pressurizing direction change transmission means by using one protrusion 43 as a force point to contact the tappet 29 and the other protrusion 44 as a force point to contact one end of the push rod 42. The horizontal pressing force generated by the stripper pressing spring 25 can be easily changed to the vertical direction and transmitted to the push rod 42, or the movement of the push rod 42 can be transmitted to the spring 25 as the pressing force. The force point projection 43 facing the spring 25 is arranged at the center of the spring housing hole 28 as shown in FIG.
[0016]
Therefore, even if the stripper pressurizing spring 25 is accommodated in the spring accommodating hole 28 of the upper die set 27, the thickness of the upper die set 27 can be reduced and the upper mold can be reduced in weight. Then, the position of the press bottom dead center becomes stable, and there is no loss of press power, so that high-speed pressing becomes possible. Further, a stripper pressing spring 25 having a long overall length can be used. Then, even if the applied pressure is the same as that of the conventional spring 13, a spring having a small spring constant and a large deflection can be used, so that it is easy to finely adjust the spring force, that is, the applied pressure. Moreover, even if a movable platen is installed on the upper die set 27, the position of the headless screw 30 can be adjusted from the side, so that the spring force can be adjusted with the press die attached to the processing die. In addition, the pressure can be easily managed.
[0017]
Further, when the force point projections 43 and 44 protrude from the swing cam 38, the distance L1 between the rotation center 40 of the swing cam 38 and the force point contacting the tappet 29 is pushed with the rotation center 40. When the distance L2 with the force point contacting the upper end of the rod 42 is larger than, for example, 4 to 3, the pressing force of the spring 25 can be increased by the lever principle, and the large pressing force can be transmitted to the push rod 42. Therefore, even a spring having a short overall length and a small applied force can be easily used as a spring for pressurizing the stripper. Of course, the ratio of L1 and L2 can be arbitrarily set.
[0018]
When a multi-pin semiconductor lead frame or the like is punched by such a press working die, if the applied pressure generated by the spring 25 is transmitted to the stripper by the downward movement of the push rod 42, the workpiece is pressed by the stripper. However, each process such as bending, crushing, and cutting can be sequentially performed with each punch. Then, when the punch reaches the bottom dead center of the press in each of these steps, the stripper moves upward away from the workpiece. Then, since it is pushed up by the stripper, as shown by the arrow in FIG. 4, the push rod 42 moves upward, and its upper end portion slightly enters the cam storage chamber 35. Therefore, when the upper end of the push rod 42 pushes up the force point protrusion 44 of the swing cam 38, the swing cam 38 rotates in the direction of the arrow, and the other force point protrusion 43 causes the tappet 29 to be in the horizontal direction indicated by the arrow. Press to. Therefore, the stripper pressurizing spring 25 is contracted to increase the applied pressure, so that the process can be shifted to the next bending, crushing, cutting or the like.
[0019]
In the above embodiment, the case where the cam holder 36 and the swing cam 38 are used as a unit has been described. However, the cam storage chamber is directly provided in the upper die set without using the cam holder, and the swing cam is provided there. May be stored.
In the above embodiment, the swing cam 38 itself is provided with a shaft. However, the shaft that is the center of rotation of the swing cam is fixed to either the upper die set or the backing plate. The swing cam and the push rod or the swing cam and the tappet may be mechanically connected to each other.
[0020]
【The invention's effect】
According to the present invention described above, according to the first aspect of the present invention, the spring accommodating hole having a certain depth is formed in the central portion in the thickness direction of the upper die set from the side surface, and the stripper is formed in the hole. The pressurizing spring is arranged so that the pressurizing direction with respect to the spring is horizontal, and the direction of the pressurizing force generated by the spring is changed and transmitted between the stripper pressurizing spring and the pressurizing force transmitting vertical motion member. As the pressurization direction conversion transmission means to be installed, a peristaltic cam that can rotate around the shaft is installed, so the horizontal pressurization generated by the stripper pressurization spring is easily converted into the vertical pressurization force It can be transmitted to the vertical motion member for transmission. Even if the spring for pressing the stripper is housed and provided in the spring housing hole of the upper die set, the thickness of the upper die set can be reduced and the upper die can be reduced in weight. Therefore, the position of the press bottom dead center becomes stable, and high-speed pressing becomes possible, thereby improving work efficiency. Further, a stripper pressing spring having a long overall length can be used in the spring housing hole of the upper die set. Therefore, a spring having a small spring constant and a large deflection can be used, and the applied pressure can be easily finely adjusted.
[0021]
According to the second aspect of the present invention, since the peristaltic cam is installed in the cam storage chamber provided with the inner wall for restricting the rotation direction, the swing cam is stored in the cam regardless of the presence or absence of the shaft serving as the center of rotation. It can be smoothly rotated indoors.
[0022]
According to a third aspect of the present invention, the distance between the pivot center of the swing cam and the force point that contacts the tappet is greater than the distance between the pivot center of the swing cam and the force point that contacts the vertical motion member for transmitting pressure. Therefore, it is possible to transmit a pressing force larger than the pressing force generated by the stripper pressing spring to the pressing force transmission vertical motion member. Therefore, even a spring having a short overall length and a small applied force can be easily used as a spring for pressurizing the stripper.
Further, in the invention described in claim 4 , since the pressure adjusting screw that contacts the outer end of the spring is installed in the spring accommodating hole for stripper pressurization, even if a movable platen is installed on the upper die set, The position of the adjusting screw can be adjusted from one side. Therefore, it is possible to adjust the spring force with the working die attached to the press device, and the pressure force can be easily managed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a structure in the vicinity of a stripper pressure spring during non-pressing of a press working mold with a horizontal stripper pressurizing mechanism to which the present invention is applied.
FIG. 2 is a plan view of the vicinity of a cam holder of an upper die set installed in the press working mold.
FIG. 3 is a side view showing the position of a protrusion serving as one of the power points of a swing cam facing a spring housing hole provided in the upper die set of the press working mold.
FIG. 4 is a longitudinal sectional view showing an operating state of a stripper pressurizing mechanism immediately after reaching the press bottom dead center of the press working mold.
FIG. 5 is a longitudinal sectional view showing the position of each component at the press top dead center of a conventional press working mold.
[Explanation of symbols]
24 ... Stripper pressurizing mechanism 25 ... Stripper pressurizing spring 26 ... Center line 27 ... Upper die set 28 ... Spring storage hole 29 ... Tappet 30 ... Pressure adjusting screw 38 ... Swing cam 39 ... Rotation direction regulating inner surface 40 ... Shaft position 41 ... Backing plate 42 ... Vertical motion member 43 for transmitting pressure force 43 ... Projection for power point

Claims (4)

A stripper pressurizing mechanism for pressing a workpiece, which includes a spring for pressurizing the stripper and a vertical motion member for transmitting a pressurizing force generated by the spring to the stripper, is installed in the upper die. In a press working mold with a stripper pressurizing mechanism that stores a pressurizing spring in a hole provided in the upper die set, the spring storing hole has a certain depth from the side at the center in the thickness direction of the upper die set. A stripper pressurizing spring is disposed in the hole so that the pressurizing direction with respect to the spring is horizontal, and the spring is interposed between the stripper pressurizing spring and the vertical motion member for applying pressure transmission. in the pressing direction converting transmission means for transmitting by changing the direction of the generated pressure, pivotable swing cam about the axis Horizontal postfix expression stripper pressure mechanism with pressing mold, characterized in that the installation. 2. The press with a horizontal stripper pressurizing mechanism according to claim 1 , wherein the peristaltic cam is installed in an upper die set or a cam storage chamber provided with an inner wall for regulating a rotation direction of a cam holder built in the upper die set. Processing mold. One force point of the peristaltic cam contacts the tappet attached to one end of the stripper pressurizing spring, the other power point of the swing cam contacts one end of the vertical motion member for pressure transmission, and the swing cam rotates. 3. The horizontal stripper according to claim 2 , wherein a distance between the center and a force point that contacts the tappet is larger than a distance between the rotation center of the swing cam and the force point that contacts the vertical movement member for transmitting pressure. Press working mold with pressure mechanism. Stripper pressurizing spring accommodating hole, according to claim 1, 2 or 3 lateral postfix expression stripper pressure mechanism with pressing mold, wherein placing the pressure adjusting screw which contacts the outer end of the spring.

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