JP4618709B2 - Resin inner container for meter and water meter - Google Patents

Description

  The present invention relates to a meter resin inner container assembled to a flow meter and a water meter including the meter resin inner container.

In the impeller-type water meter, a meter inner resin container (hereinafter simply referred to as “inner container”) is assembled, and the inner wall of the water meter flows through the bottom wall of the inner container. It is divided into an impeller accommodation chamber and a circuit accommodation chamber provided with a circuit for calculating a flow rate. And the water pressure by the water pressure and the water hammer phenomenon is applied to the bottom wall of the inner container. For this reason, the conventional inner container has a structure including ribs for improving the strength on the bottom wall. (For example, refer to Patent Document 1).
Japanese Patent Laying-Open No. 2002-5265 (FIG. 1)

  By the way, in recent years, there are plans to increase the water pressure of tap water from the current level. In addition, with the spread of the one-touch lever faucet, a water hammer phenomenon is likely to occur. For this reason, the strength improvement of the bottom wall of an inner container is calculated | required. However, when the thickness of the bottom wall or the thickness of the rib provided on the bottom wall is simply increased, there arises a problem that sink marks and voids are generated.

  “Sink” refers to a phenomenon in which partial shrinkage occurs due to a difference in cooling rate between a thin portion and a thick portion of a resin molded product, and the surface of the resin molded product is pulled and distorted. Due to the occurrence of this sink, the shape quality of the inner container is lowered. “Void” refers to bubbles generated in a resin molded product. Due to the generation of these voids, the strength decreases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inner container made of a resin for a meter and a water meter that can suppress the occurrence of sink marks and voids and improve the strength of the bottom wall as compared with the prior art. .

An inner resin container for a meter according to the invention of claim 1 made to achieve the above object is an inner resin container for a meter assembled in an impeller-type water meter, and has an inner region of the water meter. , Having a bottom wall partitioned into an impeller accommodating chamber through which tap water flows and a circuit accommodating chamber above the impeller accommodating chamber, and on the lower surface side of the bottom wall, a plurality of molded cells are formed with honeycomb cell walls It has a feature in that a honeycomb structure part having holes is integrally formed.

  According to a second aspect of the present invention, in the meter-made resin inner container according to the first aspect, the molding hole has a circular shape when viewed from the axial direction, and the diameter of the molding hole is 6 to 12 of the diameter of the bottom wall. %, And the thinnest part of the cell wall is characterized by a thickness of 0.8 to 2 mm.

  According to a third aspect of the present invention, in the resin inner container for a meter according to the first aspect, the molding hole has a hexagonal shape when viewed from the axial direction, and the diameter of the inscribed circle of the molding hole is that of the bottom wall. It is 6 to 12% of the diameter, and the thinnest part of the cell wall is characterized by a thickness of 0.8 to 2 mm.

  The invention of claim 4 is characterized in that, in the meter-made resin inner container according to any one of claims 1 to 3, the total thickness of the bottom wall and the honeycomb structure is 8 to 15 mm. Have.

The invention of claim 5 is characterized in that in the meter-made resin inner container according to any one of claims 1 to 4 , the meter is a molded product of ABS resin.

A water meter according to the invention of claim 6 is characterized in that it is provided with the resin inner container for meter according to any one of claims 1 to 5 .

According to the present invention, since the entire bottom wall of the meter-made resin inner container can be uniformly reinforced by the honeycomb-shaped cell wall provided in the honeycomb structure portion, the conventional method has been used to partially reinforce the bottom wall. The strength can be improved compared to the rib. In addition, since the strength can be improved without increasing the thickness, the occurrence of sink marks and voids can be suppressed (the inventions of claims 1 and 6 ).

  Here, in the honeycomb structure part, since the cell wall has a honeycomb shape, many welds can be generated. Specifically, if the width of the molding space in the shape of a honeycomb (that is, the thickness of the cell wall after molding) is too small in the resin molding die for the meter resin inner container, the fluidity of the molten resin is reduced. Deteriorate. Then, when the molten resin that has branched and flowed along the honeycomb eyes joined again, the joined molten resins are not fused and solidified to generate welds (resin joints). This weld can cause a decrease in strength. On the other hand, if the width of the honeycomb-shaped forming space is too large, the thickness of the cell wall becomes too large, causing the above-mentioned sinks and voids.

Therefore, as a result of intensive studies on this point, the inventors of the present application have made the diameter of the bottom wall equal to the diameter of the bottom wall when the shape viewed from the axial direction of the forming hole is circular as in the configuration of claim 2. By setting the thickness to 6 to 12% and the thickness of the thinnest portion of the cell wall to 0.8 to 2 mm, the occurrence of sink marks, voids, and welds could be suppressed. When the shape of the molding hole viewed from the axial direction is a hexagon as in the configuration of claim 3, the diameter of the inscribed circle of the molding hole is 6 to 12% of the diameter of the bottom wall, and By setting the thickness of the thinnest part of the cell wall to 0.8 to 2 mm, generation of sink marks, voids and welds could be suppressed. Here, it is preferable to set the thickness dimension of the bottom wall and the honeycomb structure portion to 8 to 15 mm (invention of claim 4). The material of the meter-made resin inner container is preferably ABS resin (acrylonitrile-butadiene-styrene copolymer resin) (Invention of Claim 5 ).

Moreover, since the bottom wall of the meter-made resin inner container receives water pressure from the lower surface side, it receives stress so that the lower surface side is recessed. Therefore, according to the configuration of the present invention in which the honeycomb structure portion is disposed on the lower surface side of the bottom wall, the honeycomb structure portion is also stressed so as to be generally recessed with the bottom wall, and at this time, the cell wall is subjected to compressive stress. Thereby, even if the weld is generated on the cell wall, the strength reduction due to the weld can be suppressed.

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the water meter 10 of the present embodiment is provided with a meter resin inner container 50 (hereinafter referred to as “inner container 50”) according to the present invention in an outer case 11. An internal region of the meter 10 is partitioned into an impeller housing chamber R1 and a circuit housing chamber R2. Specifically, the outer case 11 has a structure in which a pair of connecting pipes 15 and 15 protrudes in a direction opposite to each other from a lower end portion of a cylindrical case body 14 whose upper end is open. Then, a water pipe (not shown) is connected to the connection pipes 15 and 15, and the tap water passes through the outer case 11.

  A pivot 17 stands from the bottom wall 16 of the case body 14. The pivot 17 extends to an intermediate portion in the vertical direction of the case body 14, and an impeller 19 is rotatably supported on the pivot 17. The impeller 19 is formed by projecting a plurality of wing parts 19B radially from the rotating shaft body 19A, and tap water flowing from one connecting pipe 15 to the other connecting pipe 15 is received by the wing part 19B to obtain a flow rate of tap water. Rotates at the corresponding rotation speed. Further, a magnet 20 is fixed to the upper end portion of the rotating shaft body 19A, and the direction of the magnetic flux around the magnet 20 changes according to the rotation of the impeller 19.

  An inner container 50 is assembled to the case body 14 in a state where the impeller 19 is accommodated. The inner container 50 is an injection molded product made of ABS resin. The peripheral wall 41 of the inner container 50 has a cylindrical shape that rises vertically from the bottom wall 42, and has an outer diameter that increases stepwise on the way to the upper end side. The inner container 50 is fitted and inserted into the case main body 14 from the bottom wall 42 side, and the stepped portion 40D of the peripheral wall 41 is positioned against the stepped portion inside the case main body 14. Further, the lower end portion of the inner container 50 is fitted through a slight gap between the inner peripheral surface of the case main body 14. Thereby, the inner region of the water meter 10 is partitioned into the impeller housing chamber R1 below the bottom wall 42 of the inner container 50 and the circuit housing chamber R2 above the bottom wall 42 of the inner container 50 as described above. Has been. Further, a seal ring 30 is sandwiched between an intermediate portion in the vertical direction of the inner container 50 and the inner peripheral surface of the case main body 14. Thereby, the tap water that has flowed into the impeller housing chamber R1 of the outer case 11 through the connecting pipe 15 is prevented from entering the circuit housing chamber R2.

  The measuring unit 21 is accommodated inside the inner container 50 (that is, inside the circuit accommodating chamber R2). Further, a sealing lid 22 with a display window is joined to the upper surface of the inner container 50, and a retaining ring 23 locked to the lower end portion of the sealing lid 22 is screwed to the outer surface of the case main body 14. 50 and the sealing lid 22 are fixed to the case main body 14.

  The measuring unit 21 has a structure in which an electric circuit is sealed in a metal container. The electric circuit includes a magnetic sensor that detects the rotation of the impeller 19 in accordance with the change in the magnetic flux of the magnet 20, the CPU that calculates the flow rate of tap water based on the rotation of the impeller 19, and the flow rate. And a display device for displaying.

Now, as shown in FIG. 3, a honeycomb structure 44 is integrally formed on the bottom wall 42 of the inner container 50 on the lower surface side. The honeycomb structure portion 44 has a shape in which a plurality of forming holes 47 are partitioned by a honeycomb cell wall 48. Further, the molding hole 47 is circular when viewed from the lower surface of the inner container 50.

In the present embodiment, diameter D3 (see FIG. 2) of each molded hole 47 is set to 6-12% of the diameter D4 of the bottom wall 42 of the inner container 50 (see FIG. 2). Here, when the honeycomb structure portion 44 is provided on the lower surface side of the bottom wall 42 (that is, outside the inner container 50 of the bottom wall 42) as in the present embodiment, the diameter D4 outside the honeycomb structure portion 44 is provided. Corresponds to “the diameter of the bottom wall” according to the present invention.

  Moreover, the thickness t1 (refer FIG. 3) of the thinnest part among the cell walls 48 is 0.8-2 mm. Furthermore, the total thickness t3 (see FIG. 2) of the bottom wall 42 and the honeycomb structure 44 is 8 to 15 mm, and the thickness t2 of the honeycomb structure 44 (that is, the cell wall 48). The height dimension (see FIG. 2) is 3 to 7 mm.

As shown in FIG. 2, the central portion of the upper surface of the bottom wall 42 is slightly depressed, and a bottom protruding portion 21 </ b> T that slightly protrudes from the bottom surface of the measurement unit 21 is accommodated in the recessed portion 44 </ b> K. (See FIG. 1). A receiving portion 43 whose bottom surface is depressed upward is formed at the center of the bottom wall 42, and the upper end portion of the impeller 19 enters into the receiving portion 43.

  According to the present embodiment configured as described above, the entire bottom wall 42 of the inner container 50 can be uniformly reinforced by the honeycomb cell walls 48 provided in the honeycomb structure portion 44. Therefore, the strength can be improved as compared with the conventional rib reinforced. Moreover, since the strength can be improved without increasing the thickness, the occurrence of sink marks and voids can be suppressed.

  Further, since the shape of the molding hole 47 is circular, the manufacturing cost of the resin molding die can be suppressed, and the flow of the molten resin can be smoothed during molding, so that the occurrence of welds can be effectively suppressed. .

  Furthermore, according to the configuration of the present embodiment, even if a weld occurs in the honeycomb structure portion 44, there is an effect that it is possible to suppress the influence of the strength reduction due to the weld. That is, as shown in FIG. 4, since the bottom wall 42 of the inner container 50 receives water pressure on the lower surface, it receives stress so that the lower surface side is recessed. Therefore, by the configuration in which the honeycomb structure portion 44 is arranged on the lower surface side of the bottom wall 42 as in the present embodiment, the honeycomb structure portion 44 is also stressed so as to be recessed together with the bottom wall 42, and at this time, the cell wall 48 is Subjected to compressive stress from the horizontal direction. Therefore, even if the weld 90 extending in the vertical direction is generated on the cell wall 48, the force for expanding the weld 90 is not generated, and the strength reduction due to the weld 90 can be suppressed.

[Example]
The inner container 50 of the first embodiment was manufactured with the following dimensions. That is, the diameter D4 of the bottom wall 42 of the inner container 50 is 51 mm, the thickness dimension t2 of the honeycomb structure portion 44 is 5 mm, and the thickness dimension t3 of the bottom wall 42 and the honeycomb structure portion 44 is 10 mm. 4), the thickness t1 of the thinnest portion of the cell wall 48 is 1 mm (within the range of 0.8 to 2 mm according to claim 2), and the diameter D3 of the molding hole 47 is 5 mm (about 9.8% with respect to the diameter D4 of the bottom wall 42, within a range of 6 to 12% according to claim 2), and made of ABS resin.

  On the other hand, as compared with the conventional structure, a honeycomb structure having a rib on the bottom wall instead of the honeycomb structure portion 44 was manufactured with the following dimensions. That is, the diameter of the bottom wall of the conventional product was 51 mm, the thickness of the rib was 2 mm, and the combined thickness of the bottom wall and the rib was 10 mm.

  Then, the inner container 50 as an invented product and the conventional product are set in a pressure test jig, and water pressure is applied to the lower surface by holding for 10 seconds from 0 MPa to 0.5 MPa with a pressure pump, and the height of the bottom wall The “deformation amount” in the direction and the “pressure resistance value” that can be withstood without damaging the bottom wall were measured, and the measurement results are summarized in Tables 1 and 2.

  As shown in Table 1, the maximum value of the “deformation amount” was 0.69 mm for the conventional product, whereas it was 0.27 mm for the inner container 50 as an invention product, which was small.

  In addition, as shown in Table 2, the “pressure resistance value” was 7 MPa for the inner container 50 compared to 7 MPa for the conventional product, and increased.

  Thus, from the results of Tables 1 and 2, it was confirmed that the strength of the inner container 50 of the second embodiment was improved as compared with the conventional product. In addition, it was also confirmed that the occurrence of sink marks, voids, and welds is suppressed in the inner container 50 as an invention product.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various modifications are possible within the scope of the invention other than the following. It can be changed and implemented.

(1) of the shaped hole in the honeycomb structure section shape it is not limited to a circle type of the embodiment, for example, the shape of the molded hole, hexagonal, oval, or may be octagonal. For example, as shown in FIG. 5, when forming holes 46 are hexagonal, when the center points P <b> 1 of the adjacent forming holes 46 are connected by a line, the forming holes 46 are arranged so as to form an equilateral triangle T <b> 1. The inner surface of the formed molding hole 46 (that is, each side of the hexagon in FIG. 5) may be parallel to each other, or may be configured to be a square when the centers of the molding holes are connected by a line. At this time, it is preferable to set the diameter D2 of the inscribed circle C1 of each forming hole 46 and the thickness t4 of the thinnest portion of the cell wall 45 in the same manner as the diameter D3 and the thickness t1 in the above embodiment. .

Sectional drawing of the water meter of 1st Embodiment of this invention Side view of inner container Enlarged plan view of the bottom wall of the inner container Enlarged side sectional view of the bottom wall of the inner container Plan view of inner container according to modification

10 Water meter 14 Case body 19 Impeller
50 Inner container 42 Bottom wall 44 Honeycomb structure portion 45, 48 Cell wall 46, 47 Molding hole 90 Weld C1 Inscribed circle R1 Impeller housing chamber R2 Circuit housing chamber

Claims (6)

An inner container made of resin for a meter to be assembled in an impeller-type water meter,
The inner region of the water meter, and impeller housing chamber tap water flows, has a bottom wall that partitions into the circuit housing chamber above the said wheel housing chamber, the lower surface side of the bottom wall, honeycomb An inner container made of a resin for a meter, wherein a honeycomb structure formed by partitioning a plurality of molding holes in the cell wall is integrally formed. The molding hole has a circular shape when viewed from the axial direction, and the diameter of the molding hole is 6 to 12% of the diameter of the bottom wall;
The resin inner container for meter according to claim 1, wherein the thinnest portion of the cell wall has a thickness of 0.8 to 2 mm. The molding hole has a hexagonal shape when viewed from the axial direction, and the diameter of the inscribed circle of the molding hole is 6 to 12% of the diameter of the bottom wall;
The resin inner container for meter according to claim 1, wherein the thinnest portion of the cell wall has a thickness of 0.8 to 2 mm.   The resin inner container for a meter according to any one of claims 1 to 3, wherein a thickness dimension of the bottom wall and the honeycomb structure portion is 8 to 15 mm. 5. The meter-made resin inner container according to claim 1, wherein the meter-made resin inner container is an ABS resin molded product . A water meter, comprising the resin inner container for a meter according to any one of claims 1 to 5.

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