JPH08112721A - Manufacture of forming metal mold for water governer center core and parts having small radius of curvature - Google Patents

Abstract

PURPOSE: To machine the radius of curvature of the bottom of the concave parts of a center core into a small radius of curvature by manufacturing a forming metal mold through the complex machining of electric discharge machining executed using the first and the second forming electrode having each forming convex part. CONSTITUTION: Forming convex parts 42 corresponding to the alternate convex parts of a center core are formed on the first forming electrode 40, and on the other hand, forming convex parts 52 corresponding to the above convex parts 42 are formed on the second forming electrode 50. The XY coordinates system of the first and the second forming electrode 40, 50 is maintained at the same during the machining of the forming electrode using the first and the second forming electrode 40, 50, and electric discharge machining is executed on the same electrode blank by the first and the second forming electrode 40, 50. Thus, in the forming metal mold formed by the first and the second forming electrode 40, 50, a part corresponding to the bottom of a concave part between the convex parts of the center core becomes an acute-angled inward convex, and as a result, the radius of curvature of the bottom of the concave parts do not become larger than an ideal radius of curvature.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a center core of a water governor (simple flow rate limiting device) or a small radius equal to that of the center core.
The present invention relates to a method for manufacturing a molding die for a component having a.

[0002]

2. Description of the Related Art FIG. 10 and FIG.
The basic structure of the water governor directly targeted by the present invention will be described. This water governor aims to supply a substantially constant flow rate regardless of the upstream pressure, and it regulates the maximum flow rate of faucets in centralized boilers, tankless flush toilets, hotels, etc. It is being used for other purposes. The basic form was proposed in Japanese Examined Patent Publication No. 51-23059. This water governor includes a casing 10, a center core 20, and an O
And a ring (elastic member) 30. The center core 20 has a columnar core portion 20A and a flange portion 20B. The core portion 20A has a plurality of convex portions 21 extending in the radial direction on the outer surface thereof and concave portions 22 between these convex portions 21. Are formed. The ridge lines of the convex portion 21 and the concave portion 22 are inclined with respect to the axis of the core portion 20A. The O-ring 30 is fitted on the outer periphery of the core portion 20A of the center core 20, and forms a flow path 23 between the O-ring 30 and the recess 22. A plurality of through holes 24 are formed between the core portion 20A and the flange portion 20B of the center core 20, except for the bridge portion 25. Depending on the type, the through hole 26 may be additionally formed in the central portion. The casing 10 supports the combined body of the center core 20 and the O-ring 30, and has a stepwise cross section for receiving the flange 20B of the center core 20. The casing 10 is fixed in, for example, the water pipe 11 in a direction in which the center core 20 is pressed against the casing 10 by the pressure on the upstream side.

According to this water governor, the fluid on the upstream side (referred to as water) flows into the O-ring 30 side from the through hole 24, passes through the flow path 23 between the O-ring 30 and the concave portion 22, and reaches the downstream side. Flowing to the side. At this time, the O-ring 30 elastically deforms inward according to the flow velocity of the water passing through the flow path 23 to change the area of the flow path 23. An example of the position of the O-ring 30 after elastic deformation is shown by reference numeral 30 'in FIG. That is,
As the flow velocity is faster, the O-ring 30 is elastically deformed inward and the flow channel of the flow channel 23 is narrowed, so that a substantially constant flow rate can always be taken out to the downstream side regardless of the pressure level on the upstream side. it can.

In the mass-produced product, the center core 20 of the water governor is formed by molding a resin material. However, since the center core 20 having a small diameter has a small diameter of around 10 mm, it has been revealed that the center core 20 has the following problems. 12 to 14 show the ideal shape of the molding electrode 20F for forming the mold for the center core 20, that is, the molding having the molding convex portion 21F and the molding concave portion 22F having the same shape as the convex portion 21 and the concave portion 22 of FIG. The electrode 20F is shown. In this forming electrode 20F, the required R (radius of curvature) of the bottom of the forming recess 22F is a small R26 indicated by the solid line due to the limitation of the machining blade or the discharge gap during electric discharge machining.
Although it is r, the actual R that can be achieved becomes a large R26R. Thus, the molding recess 22F of the molding electrode 20F is formed.
If the R at the bottom of R is larger than the required R (in design), the center core 20 molded in the same shape as the molded electrode 20F cannot obtain the required flow rate limiting characteristics. That is, when the flow velocity is increased, the flow passage 23 is excessively narrowed, which causes a problem that the flow rate is reduced with respect to the pressure increase on the upstream side. In other words, R at the bottom of the recess 22 formed by the adjacent protrusions 21
The (diameter) has a great influence on the flow rate limiting characteristic, whereas the conventional center core 20 forming die cannot cope with this problem.

[0005]

It is an object of the present invention to directly provide a method of manufacturing a molding die capable of processing the bottom R of the recess of the center core into a small R, and more generally, a molding die for a small R part. The purpose is to obtain a method of manufacturing a mold.

[0006]

SUMMARY OF THE INVENTION The present invention provides a center core having a plurality of radially extending projections and recesses located between these projections; and a flow path fitted between the center core and the recesses. And a casing that supports the center core and the elastic ring and allows a fluid to flow in the flow path. A method of manufacturing a molding die for a center core of a water governor, the method comprising: A first forming electrode having a forming protrusion corresponding to every other protrusion of the protrusions, and a forming protrusion corresponding to every other protrusion of the same plurality of protrusions The second molding electrode is provided, and the molding die is manufactured by a combined machining of the electric discharge machining by the first molding electrode and the electric discharge machining by the second molding electrode. According to the mold manufactured by this method, the R of the bottom of the recess of the center core to be molded can be made sufficiently small or can have an acute angle.

If the radius R of the bottom of the recess of the center core to be molded is too small, an inward protrusion corresponding to the bottom of the recess of the center core formed by the first molding electrode and the second molding electrode is post-processed. It is sufficient to provide a step of For this post-processing, for example, a third shaping electrode for post-processing is provided, and for the mold processed by these first and second shaping electrodes,
This can be performed by working with the third shaped electrode.

More generally, the present invention relates to a molding die for resin-molding a small R component having a plurality of radially extending projections on the outer periphery and recesses located between these projections. In the manufacturing method, a first molded electrode having a molding projection corresponding to every other projection of the plurality of radial projections of the small R component, and the remaining one of the same projections. A second molding electrode having a molding convex portion corresponding to every other convex portion is provided, and the molding die is formed by a combined machining of the electric discharge machining by the first molding electrode and the electric discharge machining by the second molding electrode. It is characterized by being manufactured. If the bottom R of the recess of the center core to be molded is too small, the third molded electrode can be used as well.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a molding die of the present invention will be described below with reference to the drawings. This manufacturing method is shown in FIGS.
The present invention is applied to the manufacture of a mold for molding the center core 20 having the shape shown in FIG. 1 and 2 show the first shaped electrode 40 used in the present invention, and FIGS. 3 and 4 show the second shaped electrode 50. The first and second forming electrodes 40 and 50 have shafts 41 and 51 supported by the same electric discharge machine, respectively, and reference the XY coordinates passing through the shaft centers O1 and O2 of the shafts 41 and 51. Molding convex part 4
Equipped with 2, 52. That is, for each convex portion 21 of the center core 20 of FIG. 11, the XY coordinates passing through the axis O as shown in FIG. 11 are considered, and the convex portions 21 are denoted by the symbols A and B every other portion. Formed on the first molded electrode 40 are molded convex portions 42 corresponding to every other convex portion 21A of the center core 20,
On the other hand, on the second molded electrode 50, a molded convex portion 52 corresponding to the convex portion 21B is formed. First and second shaped electrodes 4
The XY coordinate system of 0 and 50 is defined by the first and second shaped electrodes 4
While machining the shaped electrode by 0, 50, the same electrode blank is subjected to electric discharge machining by the first and second shaped electrodes 40, 50 for the same electrode blank.

FIG. 5 shows the first and second shaped electrodes 40,
It is the figure which drew 50 by making the XY coordinate system correspond and it piled up. The thick line in the figure shows the shape of the forming protrusion 42 of the first forming electrode 40, and the thin line shows the shape of the forming protrusion 52 of the second forming electrode 50. 6 and 7 show the shape of the recess (bottomed recess) formed in the electrode blank by the first and second molded electrodes 40, 50. 6 and 7, the shape of the recess 42C formed by the forming protrusion 42 of the first forming electrode 40 is a thick line, and the recess 52C formed by the forming protrusion 52 of the second forming electrode 50 is shown.
The shape of is drawn with a thin line.

As described above, the first and second molded electrodes 40,
In the molding die formed by 50, the portion corresponding to the bottom of the concave portion 22 between the convex portions 21 of the center core 20 becomes the acute-angled inner convex portion 43. Therefore, the concave portion 22F as described in FIG. The situation where the bottom R becomes larger than the ideal R does not occur. On the other hand, since the bottom of the recess 22 of the center core 20 formed by such an inward projection 43 is sharp and deep, the flow velocity of the water passing through the flow path 23 increases and the O-ring 30 elastically deforms inward. Also in this case, there is a possibility that the flow passage area of the flow passage 23 cannot be sufficiently reduced.

In such a case, the inner convex portion 43 is post-processed. The processing line 44 in FIGS. 8 and 9 is a post-processing line for cutting and removing the tip of the inward convex portion 43. This post-processing can be performed by machining, but can also be performed by using the third shaped electrode. FIG. 9 shows the shape of the concave portion of the shaped electrode after the post-processing.
Comparing with FIG. 7, it is apparent that the tip of the inward convex portion 43 is the non-acute angle inward convex portion 43B. If the inner convex portion 43 between the concave portion 42C and the concave portion 52C is formed as the non-acute angle inner convex portion 43B, the bottom of the concave portion 22 of the center core 20 molded by this molding die becomes too deep. Therefore, when the flow velocity of water passing through the flow path 23 increases and the O-ring 30 elastically deforms inward, the flow path 23
It is possible to prevent the occurrence of a situation in which the flow passage area cannot be sufficiently narrowed. That is, it is possible to set a preferable depth (flow passage area) of the recess 22 (flow passage 23) for making the flow rate substantially constant according to an increase in the flow velocity of water passing through the flow passage 23.

While the present invention has been applied to the method for manufacturing the molding die for molding the center core 20 having the planar shape shown in FIG. 11, the present invention is not limited to the radial convex portions and the concave portions between the convex portions. In general, it is widely applicable when the bottom of the concave portion is formed into an acute angle or its R is reduced.

[0014]

As described above, according to the present invention, in the case of molding a center core of a water governor or a small R component of the same kind in which the bottom of the recess has an acute angle, or the R thereof is small, the molding die is formed. Can be manufactured easily and reliably.

[Brief description of drawings]

FIG. 1 is a plan view showing a shape example of a first molding electrode used in a method for manufacturing a molding die according to the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a plan view showing an example of the shape of a second molding electrode used in the method for manufacturing a molding die according to the present invention.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a plan view showing phases of combined processing of a first shaping electrode and a second shaping electrode.

FIG. 6 is a plan view showing a concave shape of the molding die after processing.

FIG. 7 is a partially enlarged view of FIG.

FIG. 8 is a plan view illustrating a portion (inward convex portion corresponding to a concave bottom portion of the center core) to be processed by the third molding electrode on the molding die in FIG. 6;

FIG. 9 is an enlarged plan view showing an example of the shape of the inward convex portion of the shaped electrode processed by the third shaped electrode.

FIG. 10 is a vertical cross-sectional view showing an example of a water governor directly targeted by the present invention.

11 is a plan view of the center core alone used in the water governor of FIG. 10 as seen in the direction of arrow A in FIG.

12 is a plan view of a conventional molding electrode for manufacturing the center core molding die of FIG. 11. FIG.

FIG. 13 is a side view of FIG.

FIG. 14 is a partially enlarged view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing 20 Center core 21 Radial convex part 22 Recessed part 23 Flow path 24 Through hole 25 Bridge part 30 O-ring (elastic member) 40 First molded electrode 50 Second molded electrode 41 51 Shaft 42 52 Molded convex part 42C 52C Recessed part 43 inward convex 43C non-sharp inward convex

Claims (4)

[Claims] 1. A center core having a plurality of radially extending projections on its outer periphery and recesses located between these projections;
The center core of the water governor including an elastic ring fitted to the outer periphery of the center core and forming a flow path between the center core and the recess; and a casing that supports the center core and the elastic ring and flows a fluid into the flow path. The method of manufacturing a molding die according to claim 1, wherein the first molding electrode having a molding convex portion corresponding to every other convex portion of the plurality of convex portions in the radial direction of the center core, and the same convex portion A second forming electrode having a forming convex portion corresponding to every other one of the remaining convex portions is provided, and the forming die includes an electric discharge machining by the first forming electrode and an electric discharge machining by the second forming electrode. A method for manufacturing a center core molding die of a water governor, which is manufactured by a composite process with. 2. The molding die according to claim 1, further comprising a step of post-processing an inward convex portion formed by the first molding electrode and the second molding electrode and corresponding to a bottom portion of the concave portion of the center core. Mold manufacturing method. 3. The manufacturing method according to claim 2, wherein a third molding electrode for a post-processing step is provided, and a molding die is manufactured by composite processing of these first, second and third molding electrodes. 4. A method for manufacturing a molding die for resin-molding a small R part having a plurality of radially extending projections on the outer periphery and recesses located between these projections, which is a small R part. Corresponding to every other convex portion of the same plurality of convex electrodes, and a first molded electrode having a molding convex portion corresponding to every other convex portion of the plurality of radial directions of And a second molding electrode having a molding convex portion for forming the molding die, wherein the molding die is manufactured by combined machining of electric discharge machining by the first molding electrode and electric discharge machining by the second molding electrode. A method of manufacturing a molding die for a small R part.