JPH0816482B2 - Membrane gas meter blade shaft and wing blade fastening method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fastening a blade shaft provided on a membrane gas meter to a blade.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic structure of a main part of a membrane gas meter.

In the figure, in the membrane gas meter, the membrane 1 is reciprocated by the gas pressure generated by the intake and exhaust of gas. This reciprocating motion is converted into a reciprocating rotary motion of the blade shaft 3 via the wing blade 2, this motion is converted into a rotary motion by a crank mechanism (not shown) provided on the upper part of the lower case 4, and further, a rotary motion of the upper case (not shown). The gas flow rate is displayed by a counter mechanism arranged inside. The sclera membrane 1 has a trapezoidal disc shape, and the peripheral edge is fixed to the peripheral edge of the circular opening of the lower case 4. Further, a pair of membrane plates 5 are mounted on both sides of the central flat plate portion of the sac membrane 1, and a butterfly shaft 6 provided at one end side of the sac blade 2 is rotatably attached to the center of the front surface side membrane plate 5. A pair of supporting bearings 7 is fixed. Also wing shaft 3
Is rotatably supported in a shaft hole 8 provided in the lower case 4. In the membrane gas meter configured as described above, as a method of fastening and fixing the blade shaft 3 and the conical blade 2,
Conventionally, those shown in FIGS. 4 to 6 are known. In the one shown in FIG. 4, the blade shaft 3 is made of a brass rod, and a part of the outer circumference is D-cut into a plane parallel to the axial direction. It was concluded in 9.

In FIG. 5, the blade shaft 3 is made of a brass rod, the outer periphery of the fastening portion is knurled, and the calyx blade 2 made of resin is insert-molded at the fastening portion. .

Further, in the one shown in FIG. 6, the fastening portion of the blade shaft 3 is processed so that the cross section has an oval shape, and the hole portion 10 having the same cross section is formed at one end of the camouflage blade 2 formed of resin. Then
The fastening portion of the blade shaft 2 is press-fitted into the hole 10.

[0006]

However, according to the fastening method shown in FIG. 4, the blade shaft 3 must be threaded at two places, and moreover, it is positioned by a jig during assembly,
Since it is necessary to tighten the screws from the reverse side of the ascending membrane, which is the opposite side to the assembling direction, automation of the assembling is extremely difficult.

According to the fastening method shown in FIG. 5, in order to incorporate the blade shaft 3 into which the sail blade 2 is integrally insert-molded into the lower case 4, it is necessary to insert it obliquely from the sail film forming portion. Yes, automation of assembly is impossible. Moreover, the cost is high because of insert molding.

Further, according to the fastening method shown in FIG. 6, the fastening portion of the blade shaft 3 must be machined so that its cross section has an oval shape, resulting in high cost. Moreover, the dimensional accuracy for press fitting must be controlled to within ± 0.05 mm. Further, the blade 2 and the blade shaft 3 have to be accurately positioned during the assembly, which causes a problem that the assembly takes time and the cost increases.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for fastening a blade shaft of a membrane gas meter and a vane blade, which can be easily assembled at a low cost. .

[0010]

In order to achieve the above object, according to the present invention, a sac membrane having a peripheral edge fixed inside a case and reciprocating by a supply gas pressure, is fixed to the sac membrane. A membrane gas meter having a wing blade having one end rotatably connected to a membrane plate, and a wing shaft fixed to the other end of the wing blade for transmitting the reciprocating motion of the sac membrane to a crank mechanism. A method of fastening the blade shaft and the blade, comprising the resin blade having a cylindrical hole portion at one end of the blade.
The blade shaft is made of a metal member having a polygonal cross section, and the length of the diagonal line of the blade shaft cross section is formed slightly larger than the inner diameter of the hole of the blade shaft, and the blade is heated while the fastening portion is heated. It is characterized in that the shaft is press-fitted into the hole portion of the blade and fastened.

[0011]

According to the above method, since the blade shaft can use the drawn material, the dimensional accuracy can be secured and the cost is low. Also, by forming the blades by resin injection molding, it is possible to make the blades inexpensive and highly accurate. Further, when press-fitting the blade shaft into the hole of the blade, the centering is easy, and the pressure input can be reduced by heating the fastening portion. As a result, automatic assembly becomes easy and the cost of parts can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention. In FIG. 1, the blade shaft 11 is made of a brass drawn material having a regular hexagonal cross section. Therefore, the dimensional accuracy of the cross section is ±
It can be secured to about 0.04 mm. Further, both ends where the blade shaft 11 is fitted into the shaft hole 8 shown in FIG. 3 have a circular cross section by lathe processing, and a tapered positioning boss portion 12 is provided at the lower end.
Are formed.

The wing blade 13 is formed by injection molding of synthetic resin into a dogleg shape similar to the wing blade 2 of the conventional example shown in FIG. 3, and a cylinder is provided at one end to which the blade shaft 11 is fastened. The hole 14 is provided. The inner diameter of the hole 14 is smaller than the length of the diagonal line of the hexagonal apex of the cross section of the blade shaft 11 by about 0.5 mm.

When the blade shaft 11 is press-fitted into the hole portion 14 of the blade 13 as shown in FIG. 2, the boss portion 1 at the tip of the blade shaft 11 is pressed.
By inserting 2 into the hole portion 14, it is possible to easily perform centering and positioning. Further, at the time of press fitting, the fastening portion of the blade 13 is irradiated with a light beam or the like to heat it to about 120 degrees. As a result, the pressure input is about 120 kgf.

According to this embodiment, the parts cost of the blade shaft 11 and the blade 13 can be reduced, the positioning and press-fitting of both can be facilitated, and the assembly can be easily automated.

In the above-mentioned embodiment, the blade shaft 11 is made of brass drawn material having a regular hexagonal cross section, but the material and sectional shape of the blade shaft 11 are not limited to these.

[0018]

As described above, according to the present invention, a hole is formed at one end of a sill blade made of a resin molded member, and the hole is made of a metal member having a polygonal cross section. Since the blade shaft is press-fitted while being heated, the cost of parts can be reduced, the blade shaft can be easily fastened to the blade, and the assembly can be easily automated.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a state before fastening a blade shaft and a conical blade according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a state after fastening of FIG.

FIG. 3 is an exploded perspective view showing a general configuration of a main part of a membrane gas meter.

FIG. 4 is an explanatory view showing a first example of a conventional method of fastening a blade shaft and a blade.

FIG. 5 is an explanatory view showing a second example of a conventional fastening method of the blade shaft and the blade.

FIG. 6 is an explanatory view showing a third example of the conventional method of fastening the blade shaft and the blade.

[Explanation of symbols]

 1 Capsule 4 Case 5 Membrane plate 11 Blade axis 13 Capsule blade 14 Hole

Claims (1)

[Claims] 1. A spine membrane whose peripheral edge is fixed inside a case and which reciprocates by a supply gas pressure, and a spine blade whose one end is rotatably connected to a membrane plate fixed to the spine membrane. A fastening method between the vane shaft and the vane blade in a membrane gas meter, the vane shaft being fixed to the other end of the vane blade, the vane shaft transmitting the reciprocating movement of the vane membrane to a crank mechanism, The wing blade is made of a resin molded member having a cylindrical hole at one end, the wing shaft is made of a metal member having a polygonal cross section, and the length of the diagonal line of the cross section of the wing shaft is set to the wing blade. The blade shaft of the membrane gas meter is characterized in that the blade shaft is formed slightly larger than the inner diameter of the hole, and the blade shaft is press-fitted into the hole of the blade to fasten it while heating the connecting portion. Wing fastening method.