JPH04300046A - Device for manufacturing lost foam female screw pattern for casting - Google Patents

Abstract

PURPOSE:To form a high accurate female screw continued from one end part to the other end part on the inner peripheral face of a pattern, to miniaturize a device and to reduce the cost. CONSTITUTION:One piece of a core 5 forming a male screw 5a on the outer peripheral face is inserted through and set in a metallic mold 4 under the condition of projecting the left end part thereof from left end part of the metallic mold 4. Then, the left end part of a core 5 is inserted through under the condition of screwing a screw hole 61 and connected with a motor shaft 101 through a coupling K. A driving motor 10 is fixed to a supporting table 9 arranged slidably on a slide plate 8. Further, foam plastic P is poured in a cavity C and foamed and after forming it to the prescribed shape, a switch for the driving motor 10 is turned on to rotate the core 5. Then, the core 5 is shifted together with the driving motor 10 to left direction and pulled out from left end part of the metallic mold 4 with the screw action between the foam plastic P and the hole 61 and energizing force of an energizing device H.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a disappearing female thread model for casting.

0002

2. Description of the Related Art A conventional apparatus for manufacturing a disappearing female thread model for casting is described in Japanese Patent Application Laid-Open No. 2-258136. This manufacturing device is equipped with a lower mold and an upper mold that can be released vertically, and two cores with male threads formed on the outer periphery. (Hereinafter, it may be simply referred to as a "model.") To manufacture the model, first, one ends of two cores are connected to each other. Next, the connected core is placed between the lower mold and the upper mold so as to pass through them. Next, foamed plastic is blown into the cavity formed between the inner surface of the mold and the outer surface of the core. After the foamed plastic is solidified, the two cores are rotated and moved away from each other and pulled out from both ends of the mold. Thereafter, by releasing the mold, a cylindrical disappearing female thread model for casting with a female thread formed on the inner circumferential surface is obtained.

0003

SUMMARY OF THE INVENTION In the manufacturing apparatus for a disappearing female thread model for casting having the above structure, two cores are connected to each other. In this case, it is very difficult to align the axes of the two cores. For this reason, there was a problem in that the axes of one end and the other end of the female thread of the manufactured model were misaligned with each other. In addition, when connecting two cores, it is difficult to make the ends of the threads of each core continuous, so it is necessary to connect the threads from one end to the other on the inner circumferential surface of the manufactured vanishing female thread model for casting. There was a problem in that it was not possible to form a continuous female thread up to the end. Furthermore, it is necessary to provide rotational drive mechanisms for rotationally moving the two cores at both ends of the mold. For this reason, there have been problems in that the device becomes larger and the cost of the device increases. The present invention was made against the background of the above-mentioned conventional technical problems, and it is possible to form a female screw whose axis does not shift between one end and the other end, and also to create a disappearing female screw model for casting. A manufacturing device for a disappearing female thread model for casting, which can form a continuous high-precision female thread from one end to the other on the inner circumferential surface of the machine, and further reduce the size and cost of the device. The purpose is to provide.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a mold for a disappearing female thread model for casting provided in a frame, and a mold having one end protruding from the mold. a core that is inserted through the frame so as to be insertable and removable and rotatable, and has a male thread formed on its outer periphery; a female thread member that is fixed to the frame and into which the core is screwed; and the frame. is provided movably in the axial direction of the core,
and a rotational drive mechanism for rotating the core.

[0005]

[Operation] A single core having a male thread formed on the outer periphery is inserted into the mold with one end protruding from the mold. At this time, one end of the core protruding from the mold passes through the female screw member in a screwed state and is connected to the rotational drive mechanism. Next, foamed plastic is injected into the mold and foamed to form a predetermined shape. Next, after the foamed plastic has solidified, the core is rotated by a rotation drive mechanism. Then, due to the screw action between the foamed plastic and the internally threaded member, the core moves together with the rotary drive mechanism in a direction away from the mold, and is pulled out from one end of the mold. Thereafter, by releasing the mold, a disappearing female thread model for casting is obtained.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. In addition, in explaining this example,
First, a disappearing female thread model for casting manufactured by the manufacturing apparatus of this embodiment will be explained. FIG. 8 shows a part of the disappearing female thread model 1 for casting cut away, and this model 1 is formed in an elongated cylindrical shape. A continuous internal thread 1a from one end to the other end is formed on the inner circumferential surface thereof.

FIGS. 1 to 4 show a manufacturing apparatus 2 for a vanishing internal thread model 1 for casting, which is the present embodiment. It includes a book core 5, a female screw member 6, and a rotational drive mechanism 7.

The mold 4 has a frame 3 as shown in FIG.
It has an upper mold 4a and a lower mold 4b. By abutting the upper mold 4a and the lower mold 4b against each other, a cavity 4c having a circular cross section corresponding to the model 1 is formed inside the mold 4. In this case, the lower die 4b is
It is formed deeper than the upper mold 4a, and the axis of the cavity 4c is located slightly downward from the upper end of the lower mold 4b. A through hole 41 extending on the axis of the cavity 4c is formed at the left end of the lower mold 4b. This through hole 4
1 is for arranging the core 5, which will be described later, in the mold 4 so that it can be inserted and removed and rotated with the rear end (left end) of the core 5 protruding from the left end of the mold 4. Its inner diameter is the same as or slightly larger than the outer diameter of the core 5. On the other hand, a recess 42 is formed at the right end of the lower die 4b on the axis of the cavity 4c.

The core 5 is formed into a long cylindrical shape, as shown in FIG. A male thread 5a corresponding to the female thread 1a of the model 1 is formed on the outer peripheral surface of the core 5 from the tip (right end) to the vicinity of the rear end (left end). The dimension of this male screw 5a in the axial direction is longer than the dimension from the left end to the right end of the mold 4. Further, the rear end portion of the core 5 has a non-threaded portion 5b having a non-threaded outer periphery. The core 5 configured in this way is inserted into the cavity 4 of the mold 4.
It is arranged so as to penetrate through c. That is, with the right end of the core 5 fitted into the recess 42 and the left end rotatably and slidably passing through the through hole 41, the axis of the core 5 and the cavity 4c are aligned. It is arranged in the mold 4 so that the axes of the two sides coincide with each other. Then, the core 5 is the mold 4
By being arranged so as to penetrate the cavity 4c of
A cavity C having the same shape as the model 1 is formed between the inner surface of the mold 4 and the outer surface of the core 5.

As shown in FIGS. 1 and 2, the female screw member 6 is formed into a block shape, and is screwed to the frame 3 while contacting the left end of the mold 4. A screw hole 61 penetrating from the left end to the right end is formed in the center of the female threaded member 6 so as to coincide with the axis of the cavity 4c. Further, the male thread 5a of the core 5 is screwed into the inner circumferential surface of the screw hole 61. Note that a sealing material (such as an O-ring), not shown, is provided between the mold 4 and the female threaded member 6, thereby creating an airtight state between them.

As shown in FIGS. 1 and 2, the rotational drive mechanism 7 includes a slide plate 8, a support base 9, and a drive motor 10 with a reduction gear. As shown in FIGS. 1 and 2, the slide plate 8 is formed into a rectangular plate shape that is long in the left-right direction, and is arranged so that its longitudinal direction is parallel to the axis of the cavity 4c, and its right end is connected to the frame. It is fixed to the left end of 3. In addition, in the figure, reference numeral H denotes a biasing device for biasing the drive motor 10 leftward to facilitate the withdrawal of the core 5.

As shown in FIGS. 2 and 3, the support stand 9 includes guide portions 91 and 92 each having a U-shaped cross section and which are slidably fitted to the left and right sides of the slide plate 8, respectively, and these guide portions 91. , 92 extending upwardly from each other.
, 94.

The drive motor 10 rotates the core 5, and as shown in FIGS. 1 and 2, supports plates 93 and 94.
The axis of the motor shaft 101 is aligned with the axis of the core 5 and fixed. The motor shaft 101 is connected to the non-threaded portion 5b of the core 5 via a coupling K.

Further, the motor shaft 101 is provided with a steam inflow mechanism 20 for causing steam to flow into the hollow portion of the core 5. This steam inflow mechanism 20 includes a rotating body 201,
A support member 202 is provided.

As shown in FIGS. 1 and 2, the rotating body 201 is formed into a thick-walled cylindrical shape, and is fixed with its hollow portion fitted into the tip of the motor shaft 101. As shown in FIG. 3, the rotating body 201 has a plurality of grooves 20 (eight in this embodiment) that penetrate from the outer circumferential surface to the inner circumferential surface.
3... are formed along the axis at a pitch of 45° (see Fig. 3). The tip of the motor shaft 101 described above is formed into a cylindrical shape, as shown in FIGS. 2 and 3. In addition, the tip of the motor shaft 101 has a plurality of grooves 10 (eight in this embodiment) that penetrate from the outer circumferential surface to the inner circumferential surface.
2... are formed along the axis at a pitch of 45°. These grooves 102... are the grooves 2 of the rotating body 201.
03... are arranged so as to communicate with each other.

The support member 202 rotatably supports the rotating body 201 therein, and is formed into a box shape as shown in FIGS. 2 and 3. The support member 202 is prevented from rotating by stoppers 204 and 205 provided on the support plates 93 and 94. In addition, the support member 20
2, as shown in FIG.
6... are formed at three locations in total. These steam inlets 2
At least one of the grooves 203 of the rotary body 201 communicates with any of the grooves 203 of the rotary body 201 when the rotary body 201 stops at an arbitrary position. Note that a sealing material (such as an O-ring), not shown, is provided between the steam inflow mechanism 20 and the coupling K, so that
There is an airtight condition between them.

Next, the operation of the manufacturing apparatus 2 will be explained. First, as shown in FIG. 5, the core 5 is placed through the cavity 4c of the mold 4. As a result, a cavity C having the same shape as the model 1 is formed between the inner surface of the mold 4 and the outer peripheral surface of the core 5. At this time, the right end of the core 5 is fitted into the recess 42, and the left end of the core 5 is rotatably and slidably passed through the through hole 41. In addition, the left end of the core 5 is
It passes through the female screw member 6 in a screwed state, and the coupling
The motor shaft 101 of the drive motor 10 is connected to the motor shaft 101 of the drive motor 10 via. Note that the drive motor 10 is biased leftward by a biasing device H.

Next, a foamed plastic P that has been pre-foamed to a diameter of about 0.9 mm is injected into the cavity C through the injection port T formed in the upper mold 4a, and the inside of the mold 4 is heated with steam. Then, as shown in FIG. 6, the foamed plastic P is expanded and filled into the entire cavity C.

To heat the inside of the mold 4 with steam, steam is introduced into the steam inlet 206 of the steam inlet mechanism 20 . At this time, the steam inlet 206 into which the steam flows is in communication with any of the grooves 203 of the rotating body 201 (see FIG. 3). Therefore, the steam flowing into the steam inlet 206 flows through the groove 203, the groove 102, and the motor shaft 10.
1 and the hollow part of the coupling K to the core 5.
flows into the hollow part of. As a result, the core 5 is heated,
Heat is transferred into the mold 4.

Next, the mold 4 is cooled with water to solidify the foamed plastic. Thereafter, the switch (not shown) of the drive motor 10 is turned on to rotate the core 5. Then, the core 5 moves together with the drive motor 10 in the direction of leaving the mold, that is, to the left in FIG. Finally, as shown in FIG. 7, it is pulled out from the left end of the mold 4. Thereafter, by releasing the mold, a cylindrical disappearing female thread model 1 for casting with a female thread 1a formed on the inner circumferential surface as shown in FIG. 8 is obtained.

[0021] In the manufacturing apparatus for the disappearing female thread model 1 for casting having the above structure, one core 5 having a male thread 5a formed on its outer peripheral surface is used. Therefore, it is possible to form a female thread 1a in which the axis line does not shift between one end and the other end in the manufactured disappearing female thread model 1 for casting.

[0022] Furthermore, by using one core,
A highly accurate internal thread 1a that is continuous from one end to the other end can be formed on the inner circumferential surface of the model 1.

Furthermore, in order to pull out the core 5 only from the left end of the mold 4, the rotation drive mechanism 7 for rotating the core 5 is
It is sufficient to provide it only at the left end of the mold 4. Therefore, it is possible to reduce the size and cost of the entire device.

Furthermore, in this embodiment, the rear end of the core 5 is connected to the motor shaft 101 of the drive motor 10 to rotate the core 5. Therefore, the rotational drive mechanism 7 can be made smaller than when the core 5 is rotated using a gear mechanism or the like. Therefore, a plurality of cores 5 can be inserted through the mold, that is, so-called multiple cores can be inserted, and productivity can be improved.

The present invention is not limited to the above-mentioned embodiments, but can be modified without departing from the gist of the present invention. For example, in this embodiment, a cylindrical core 5 is used, but it is not necessarily limited to this.
A cylindrical shape can also be used.

Further, in this embodiment, the rear end of the core 5 is connected to the motor shaft 101 of the drive motor 10 to rotate the core 5, but it is not necessarily limited to this, and a gear mechanism may be used. Alternatively, it is also possible to rotate the core 5 by employing a chain mechanism or the like. However, if a gear mechanism or the like is employed, the rotary drive mechanism 7 becomes large-sized, so the above-mentioned so-called so-called multiple installation is restricted.

[0027]

[Effects of the Invention] According to the manufacturing device for a vanishing female thread model for casting of the present invention, there is a mold for a vanishing female thread model for casting provided on a frame, and a state in which one end protrudes from the mold. a core that is inserted through the frame so as to be insertable and removable and rotatable, and has a male thread formed on its outer periphery; a female screw member that is fixed to the frame and into which the core is screwed; A rotational drive mechanism is provided that is movable in the axial direction of the core and rotates the core. Therefore, it is possible to form a female thread in the manufactured model in which the axis does not shift between one end and the other end, and moreover, it is possible to form a highly accurate female thread that is continuous from one end to the other end. Furthermore, it is possible to achieve the effects of miniaturizing the device and reducing costs.

[Brief explanation of drawings]

FIG. 1 is an overall view of a manufacturing apparatus for a disappearing female thread model for casting according to the present invention.

FIG. 2 is a view taken along arrow II in FIG. 1;

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is a sectional view of a main part of the core.

FIG. 5 is a diagram showing a state in which the core is inserted through the mold.

FIG. 6 is a diagram showing a state in which the cavity is filled with foamed plastic.

FIG. 7 is a diagram showing a state in which the core has been pulled out from one end of the mold.

FIG. 8 is an overall perspective view of a disappearing female thread model for casting manufactured by the manufacturing apparatus of the present invention.

[Explanation of symbols]

1 Disappearing female thread model for casting 2 Manufacturing device for vanishing female thread model for casting 3 Frame 4 Mold 5 Core 6 Female thread member 7 Rotation drive mechanism

Claims (1)

[Claims] Claim 1: A mold for a vanishing female thread model for casting provided on a frame, and a mold disposed through the mold so that it can be inserted and removed and rotated with one end protruding from the mold, and one core having a male thread formed on its outer periphery; a female screw member fixed to the frame and into which the core is screwed; A manufacturing device for a vanishing female thread model for casting, characterized by comprising a rotation drive mechanism for rotating a core.