JPH0540977Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a stamping molding apparatus for thermoplastic resin sheets.

2. Description of the Related Art A stamping molding device is equipped with a male die and a female die, and performs stamping molding on a thermoplastic resin sheet by pressing the preheated and softened thermoplastic resin sheet with the male die and female die. It has been known.

Problems to be solved by the invention By the way, when it is necessary to form a through hole in a molded product by stamping molding, it is usually possible to form the through hole by post-processing such as punching or drilling. However, it increases manufacturing man-hours, making it difficult to obtain sufficient productivity and increasing costs. On the other hand, there are problems in that it is difficult to make the inner circumferential surface of the through hole smooth and it is difficult to obtain sufficient dimensional accuracy of the through hole. It was hot.

On the other hand, a protrusion is provided on one of the molding surface of the male die and the molding surface of the female die, and a fitting hole into which the protrusion is fitted is provided on the other of both molding surfaces. If the through hole is formed by performing stamping molding on the thermoplastic resin sheet using a mold and at the same time extruding a part of the thermoplastic resin sheet into the fitting hole using the protrusion,
It is believed that the above-mentioned problem can be solved.

However, in this case, the fitting hole is
Usually, it is constructed with a through hole or a deep hole with a bottom, so the amount of material extruded into the fitting hole of the thermoplastic resin sheet may vary, resulting in a shortage of material, which can lead to chipping of the molded product. Otherwise, there is a risk that the dimensional accuracy of the molded product, such as the wall thickness, may be impaired.

The present invention was developed against the background of the above circumstances, and its purpose is to form a through hole by pushing out a part of the thermoplastic resin sheet into the fitting hole using the protrusion at the same time as stamping molding. An object of the present invention is to provide a stamping molding apparatus that can suitably prevent material shortage by keeping the amount of the thermoplastic resin sheet pushed out into the fitting hole substantially constant.

Means for Solving the Problems In order to achieve the above object, the present invention includes a male mold and a female mold, and presses a thermoplastic resin sheet that has been softened by heating with the male mold and female mold. The stamping molding apparatus is of a type that performs stamping molding on the thermoplastic resin sheet and forms through holes at the same time, and (a) the male molding surface is formed on one of the molding surface of the male mold and the molding surface of the female mold. (b) a protrusion that protrudes in the pressing direction of the mold and the female mold and has a protrusion height greater than the thickness dimension of the thermoplastic resin sheet after stamping molding; (c) a bottomed fitting hole provided on the other molding surface of the mold, into which the thermoplastic resin sheet is filled during the stamping molding and into which the protruding portion is fitted by a predetermined amount; and (c) a bottom surface of the fitting hole. (d) a movable member that is fitted into the hole so as to be movable toward and away from the protrusion, and is prevented from moving beyond a certain limit in the direction toward the protrusion; and (e) constantly biasing the movable member in a direction approaching the protrusion and filling the fitting hole until the protrusion starts fitting into the fitting hole during stamping molding. Although the thermoplastic resin sheet is not elastically compressed and deformed through its movable member due to the pressure of the thermoplastic resin sheet, after the protrusion starts fitting into the fitting hole, the heat filled in the fitting hole It is characterized by including a spring that is elastically compressed and deformed via its movable member as the pressure of the plastic resin sheet increases.

Function and Effect of the Invention According to the thermoplastic resin sheet stamping molding apparatus configured as described above, the thermoplastic resin sheet, which has been heated and softened in advance, is pressed by the male mold and the female mold, thereby the heat is applied to the thermoplastic resin sheet. Stamping is performed on the thermoplastic resin sheet, and at the same time as the stamping is being performed, the protruding portion is fitted into the fitting hole by a predetermined amount, so that a part of the thermoplastic resin sheet is pushed out into the fitting hole by the protruding portion. Then, a through hole is formed in the thermoplastic resin sheet. At this time, until the protrusion starts fitting into the fitting hole, the movable member resists the biasing force of the spring and is separated from the protrusion due to the pressure of the thermoplastic resin sheet filled in the fitting hole. Therefore, the amount pushed into the fitting hole of the thermoplastic resin sheet can be approximately constant based on the volume of the fitting hole. After this starts, as the pressure of the thermoplastic resin sheet filled in the fitting hole increases, the thermoplastic resin sheet is caused to flow into the hole, and the movable member resists the biasing force of the spring. Since the protrusion is pushed in the direction away from the protrusion, even if the bottomed fitting hole is filled with a thermoplastic resin sheet, the protrusion can be easily fitted to the fitting hole by a predetermined amount.
Through holes can be formed in the thermoplastic resin sheet.

As a result, through-holes are formed in the thermoplastic resin sheet at the same time as stamping molding, which reduces manufacturing man-hours, improves productivity, and reduces costs compared to the conventional method of forming through-holes through post-processing. In addition, the inner peripheral surface of the through hole can be made smooth and the dimensional accuracy of the through hole can be improved. Moreover, by making the amount pushed out into the fitting hole of the thermoplastic resin sheet approximately constant during stamping molding, material shortages can be effectively prevented, thereby preventing chips from occurring in the molded product. This can be suitably prevented and the dimensional accuracy of the molded product, such as its wall thickness, can be suitably ensured.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing the main parts of a stamping molding apparatus to which the present invention is applied, and includes an upper mold 10 and a lower mold 12. The upper die 10 has a convex portion 14 and is fixed to a movable platen of a press device (not shown), and the lower die 12 has a concave portion 16 into which the convex portion 14 is fitted, and is fixed to a movable platen of a press device (not shown). It is fixed to a fixed platen (not shown). Therefore, in this embodiment, the upper mold 10 corresponds to the male mold, and the lower mold 12 corresponds to the female mold. Molding surface 18 of convex portion 14
A protrusion 20 that protrudes toward the lower mold 12 in the moving direction of the upper mold 10 is integrally provided at the center of the mold. In this embodiment, the protrusion height of the protrusion 20 is determined by the height of the thermoplastic resin sheet 50, which will be described later.
It is smaller than the thickness of the thermoplastic resin sheet 50 before stamping, but larger than the thickness of the thermoplastic resin sheet 50 after stamping.

A bottomed fitting hole 24 into which the protrusion 20 is fitted during stamping molding is provided at the center of the molding surface 22 of the recess 16 and at a position facing the protrusion 20 . This fitting hole 24
The depth dimension is such that the thermoplastic resin sheet 50 is filled in the fitting hole 24 before the fitting of the protruding part 20 into the fitting hole 24 starts, and the depth dimension of It is predetermined in advance to be a predetermined dimension larger than the total dimension, and in this example, the dimension is determined to be sufficiently smaller than the thickness of the charged material (thickness of the thermoplastic resin sheet 50 before stamping molding). There is.

At the center of the bottom of the fitting hole 24, there is a medium diameter hole 2.
6. A through-hole 32 consisting of a large-diameter hole 28 and a small-diameter hole 30 is provided, and on the outer periphery of the bottom of the fitting hole 24, for example, 3 through-holes are provided at predetermined intervals in the circumferential direction.
(only two shown) through holes 34 are provided. An ejector pin 36 is inserted into the through hole 32, and an ejector pin 38 is inserted into each through hole 34, respectively. These ejector pins 36 and 38 are each fixed to a plate-like member 40 that is provided in the lower mold 12 so as to be movable toward and away from the upper mold 10.
A rod 41 protruding from the surface of the plate member 40 opposite to the ejector pins 36 and 38 is driven by a drive device (not shown), so that the retracted position shown in FIG. 1 and the retracted position shown in FIG. It is designed to be actuated in two positions, including the extended position shown. The distal end surface of the ejector pin 36 is substantially flush with the bottom surface of the fitting hole 24 in the retracted position, and the distal end surface of each ejector pin 38 is flush with the bottom surface of the recess 16 in the retracted position. .

At the tip of the ejector pin 36, there is a cylindrical portion 42 having an axial length that is approximately the same as the axial length of the medium-diameter hole portion 26 of the through hole 32, and a cylindrical portion
A movable member 46 consisting of a flange portion 44 protruding toward the outer circumferential side at one end of 2 is slidably fitted. The outer circumferential surface of the cylindrical portion 42 is connected to the medium diameter hole 2.
6, and the flange portion 44 is positioned within the large diameter hole 28 of the through hole 32, and the flange portion 44 is connected to the medium diameter hole 26 and the large diameter hole. Based on the contact with the stepped surface formed between the parts 28, the protruding part 2 of the movable member 46
Movement beyond a certain limit in the direction approaching zero is prevented. Therefore, in this embodiment, the medium-diameter hole portion 26 corresponds to a hole. The flange portion 44 of the movable member 46 and the large diameter hole portion 2
8 and the stepped surface formed between the small diameter hole 30 on the outer peripheral side of the ejector pin 36.
A compression coil spring 48 is inserted with a predetermined preload applied thereto. As a result, the movable member 46 is always urged in the direction approaching the protrusion 20 according to the urging force of the compression coil spring 48, and the step between the flange 44 and the large diameter hole 28 and the small diameter hole 30 In the state of contact with the attached surface, as shown in FIGS. 2 to 4, the movable member 4
The end surface of 6 on the side opposite to the flange portion 44 is substantially flush with the bottom surface of the fitting hole 24 . The compression coil spring 48 constitutes the spring of this embodiment, and its preload is maintained in the fitting hole 24 until the protrusion 20 starts fitting into the fitting hole 24. Although the movable member 46 is not elastically compressed and deformed due to the pressure of the thermoplastic resin sheet 50 filled in the fitting hole 24 of the protrusion 20
After the fitting is started, the thermoplastic resin sheet 50 filled in the fitting hole 24 is elastically compressed and deformed via the movable member 46 as the pressure of the thermoplastic resin sheet 50 increases. It is predetermined in relation to the viscosity, etc. of 50. In addition, upper mold 1
0 and the lower mold 10, cooling water or the like is normally refluxed.

Next, the operation of the stamping forming apparatus configured as above will be explained based on FIGS. 1 to 5.

First, as shown in FIG. 2, with the upper mold 10 raised, a predetermined thermoplastic resin sheet (hereinafter abbreviated as sheet) that has been heated and softened in advance is placed on the bottom surface of the recess 16 of the lower mold 12. 50 is placed. Next, by lowering the upper mold 10, the third
As shown in FIGS. 4 and 1, the sheet 5
0 is subjected to stamping molding to form a molded product 52 having a bottomed cylindrical shape, and the molded product 5
A through hole 54 is formed in the center of the bottom of the 0. That is, in the state shown in FIG. 3, the upper die 10 and the lower die 12 have started pressing the sheet 50, and the fitting hole 24 has already been filled with the sheet 50, but the protrusion does not occur. The fitting of the part 20 into the fitting hole 24 has not yet started. Next, the upper mold 10
When the protrusion 20 is further lowered from the position shown in the figure, the protrusion 20 starts fitting into the fitting hole 24. FIG. 4 shows the point at which the fitting starts. Up to this point, the movable member 46 has not been pushed away from the protrusion 20 by the resin pressure in the fitting hole 24 against the biasing force of the compression coil spring 48; 10 is lowered together with the protrusion 20, as the resin pressure in the fitting hole 24 increases, the inner circumferential surface of the medium diameter hole 26 of the through hole 32 and the ejector pin 36 A fitting hole 24 is formed in the annular space formed between the outer peripheral surface of the
While the resin inside is made to flow, the movable member 46 is pushed in a direction away from the protrusion 20 against the biasing force of the compression coil spring 48 . This results in
Even if the bottomed fitting hole 24 is filled with resin,
Since the protrusion 20 can be easily fitted into the fitting hole 24 by a predetermined amount, a through hole 54 having the same diameter as the protrusion 20 is formed in the center of the sheet 50, more precisely, in the center of the molded product 52. It is formed. After cooling the resin in this state for a predetermined period of time until it solidifies, the upper mold 10 is raised and the ejector pins 36 and 38 are respectively protruded by the drive device, thereby forming the resin as shown in FIG. part 52 and the extruded portion 56 into the fitting hole 24
is released from the lower mold 12. Next, after removing the molded product 52 and the extruded portion 56 and retracting the ejector pins 36, 38, the next sheet 50 is placed on the bottom surface of the recess 16 of the lower mold 12, and the process is performed in the same manner as in the above case. A molded product 52 having a through hole 54 formed therein is then molded.

As described above, according to this embodiment, at the same time that the sheet 50 is stamped by the upper die 10 and the lower die 12, the protrusion 20 protruding from the molding surface 18 of the upper die 10 is stamped. A through hole 54 is formed in the sheet 50 (molded product 52) based on the fit with the fitting hole 24 provided on the molding surface 22 of the lower die 12, so such a through hole 54 can be formed by punching or drilling. Compared to the conventional case of forming by post-processing such as machining, the number of manufacturing steps is reduced, productivity is improved, and costs are reduced. Improves dimensional accuracy.

Further, according to this embodiment, until the protrusion 20 starts fitting into the fitting hole 24, the fitting hole 24 is closed.
Because the movable member 46 is not pushed in the direction away from the protrusion 20 against the biasing force of the compression coil spring 48 due to the resin pressure in the seat 50, the amount pushed into the fitting hole 24 of the seat 50 is limited to the amount that is pushed into the fitting hole 24. It is assumed to be approximately constant based on the volume of 24. As a result, it is possible to effectively prevent the occurrence of material shortages, and therefore it is possible to suitably prevent the occurrence of chips, etc. at the opening side end of the molded product 52, which has a cylindrical shape with a bottom. The dimensional accuracy of the bottom wall thickness, etc. can be suitably ensured.

In addition, in the above-mentioned embodiment, the molded product 52 having a bottomed cylindrical shape having one through hole 54 at the bottom is molded, but it is possible to form two or more through holes. Alternatively, a molded product having a shape other than a cylindrical shape with a bottom may be molded.

Further, in the above embodiment, the protrusion height of the protrusion 20 is smaller than the thickness dimension of the sheet 50 before stamping, but the protrusion height of the protrusion is smaller than the thickness of the sheet 50 before stamping. It is possible to obtain the effects of the present invention even when the size is larger than the length. In this case, the fitting of the protrusion into the fitting hole will start before the upper die 10 and the lower die 12 start pressing the sheet 50. In short, the height of the protrusion only needs to be larger than the thickness of the thermoplastic resin sheet after stamping molding.

Further, in the above embodiment, the movable member 46 is configured to have the cylindrical portion 42 and the flange portion 44, but this is not necessarily necessary.
As shown in the figure, it may be a movable member 62 consisting of a cylindrical portion 58 and a flange portion 60 protruding toward the outer circumference at one end thereof. In Figure 6,
In place of the ejector pin 36, a joint pin 64 having a male thread formed at one end is fixed to the plate member 40 at the other end, and has a cylindrical shape with a bottom, and has a through hole 66 in the center of the bottom. A protruding member 68 having the joint pin 64 is screwed onto the male thread of the joint pin 64 on the side opposite to the bottom side. The protruding member 68 is slidably fitted into a through hole 70 provided at the bottom of the fitting hole 24,
In the retracted position of the protruding member 68, the end surface of the protruding member 68 on the side opposite to the joint pin 64 is substantially flush with the bottom surface of the fitting hole 24, and substantially covers a part of the bottom surface of the fitting hole 24. It consists of The cylindrical portion 58 is slidably fitted into the through hole 66, and the flange portion 60 and the protruding member 6
The movable member 62 is disposed inside the protruding member 68 and is prevented from moving beyond a certain limit in the direction approaching the protruding portion 20 due to contact with the bottom of the joint pin 64 . Movable member 6
A compression coil spring 72 is inserted between the two. Therefore, in this embodiment, the through hole 66 corresponds to a hole. Even in this case, substantially the same effect as in the above-described embodiment can be obtained. In FIG. 6, the same parts as in the above-described embodiment are designated by the same reference numerals, and detailed explanation thereof will be omitted.

Furthermore, in the above embodiment, the upper mold 10 is a male mold.
A protrusion 20 is provided protrudingly on the molding surface 18 of the lower mold 12, and a fitting hole 24 into which the protrusion 20 is fitted is provided on the molding surface 22 of the lower mold 12, which is a female mold. Conversely, a protrusion may be provided on the molding surface of the female mold, and a fitting hole into which the protrusion is fitted may be provided on the molding surface of the male mold. In this case, the female mold can be used as the upper mold and the male mold can be used as the lower mold.

Furthermore, in the above embodiment, the upper die 10 is fixed to the movable platen of the press device and the lower die 12 is fixed to the fixed platen, but the upper die 10 is fixed to the fixed platen of the press device and the lower die 12 is fixed to the movable platen of the press device. It is also possible to configure the mold 12 to be fixed to a movable platen.

In addition, various changes may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the stamping molding apparatus of the present invention, and shows a state in which mold clamping is completed. FIG. 2 is a diagram showing a state in which a softened thermoplastic resin sheet is placed on the lower mold of FIG. 1, and is a diagram showing the main parts. 3 and 4 are views showing the main parts of the apparatus shown in FIG. 1 in a state in the middle of stamping forming, and FIG. 3 shows the state immediately before the protrusion starts fitting into the fitting hole. , and FIG. 4 shows the starting point of fitting of the protrusion into the fitting hole, respectively. FIG. 5 is a diagram showing a mold release operation of a molded product etc. molded by the apparatus shown in FIG. 1. FIG. 6 is a diagram showing another example of the present invention, and corresponds to FIG. 1. 10... Upper mold (male type), 12... Lower mold (female type),
18, 22...molding surface, 20...protrusion, 24...
...Fitting hole, 26...Medium diameter hole (hole), 46, 62
... Movable member, 48, 72 ... Compression coil spring (spring), 50 ... Thermoplastic resin sheet, 54 ... Through hole, 66 ... Through hole (hole).

Claims (1)

[Claims for Utility Model Registration] Stamping on a thermoplastic resin sheet comprising a male mold and a female mold, by pressing a preheated and softened thermoplastic resin sheet with the male mold and the female mold. The stamping molding device is of a type that forms a through hole at the same time as performing molding, and the stamping molding device is provided with a molding surface of the male mold and a molding surface of the female mold protruding in the pressing direction of the male mold and the female mold, a protrusion having a protrusion height larger than the thickness dimension of the thermoplastic resin sheet after stamping molding; a bottomed fitting hole filled with a plastic resin sheet and into which the protrusion is fitted by a predetermined amount; a hole provided at the bottom of the fitting hole; and a hole movable toward and away from the protrusion. a movable member that is fitted into the hole and prevented from moving beyond a certain limit in the direction approaching the protrusion; and the movable member is constantly biased in the direction approaching the protrusion during stamping forming. Until the protrusion starts fitting into the fitting hole, it is not elastically compressed and deformed via the movable member due to the pressure of the thermoplastic resin sheet filled in the fitting hole. After the protrusion starts fitting into the fitting hole, the spring is elastically compressed and deformed via the movable member as the pressure of the thermoplastic resin sheet filled in the fitting hole increases. A stamping molding device for a thermoplastic resin sheet, comprising: