JPS634974Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a positive displacement flowmeter in which the rotation of a rotor is transmitted to a counting section via a magnetic coupling.

Conventionally, as this type of flowmeter, the one shown in FIG. 1 is known. That is, 1 in the figure is the casing,
The casing 1 includes a casing body 1A and a bolt 2.
A lid body 1 that is placed on the casing body 1A by
It consists of B. The casing 1 is formed with an inlet and an outlet (both not shown) for the fluid to be measured in the vertical direction in the plane of the paper in FIG. 1, and a measuring chamber 3 is provided within the casing 1. A pair of oval gear type rotors 4 and 5 are provided in the measuring chamber 3 so as to mesh with each other, and bearings 6 and 7 made of carbon material are provided in the center holes 4A and 5A of each of the rotors 4 and 5. It is fixedly provided by means of press-fitting, driving, etc. (hereinafter referred to as press-fitting). In one bearing 6, a driving magnet 8 made of ferrite, alnico (trade name), samarium cobalt, etc. is located between the bearing 6 and the center hole 4A and is flush with the outer peripheral surface of the bearing 6. It is buried so that it becomes, and is press-fitted into the center hole 4A together with the bearing 6. 9 and 10 are rotors 4 and 5
The support shafts 9 and 10 are for rotatably supporting the casing body 1A and the lid body 1B.
They are fixed liquid-tightly in between. The support shafts 9, 10
The inner circumferential surfaces of bearings 6 and 7 are rotatably inserted through the outer circumferential surfaces of the rotors 4 and 5 with a slight gap, thereby supporting the rotors 4 and 5. Here, one of the support shafts 9 is configured as a hollow shaft with a bottom, and a hollow chamber 1 is provided in the support shaft 9.
1 is formed. Further, 12 indicates a rotation transmission shaft, one end of the rotation transmission shaft 12 is disposed within the hollow chamber 11, and the other end is provided with a counting section (not shown) such as an integration counter and a pulse transmitter. Further, the rotating shaft 12 is supported by a bearing member 13 midway. Further, within the hollow chamber 11, a driven magnet 14 is fixed to the rotation transmission shaft 12 at a position corresponding to the main driving magnet 8, and each magnet 8, 1
4 constitutes a magnetic joint.

In the positive displacement flowmeter configured in this way,
When the fluid to be measured flows from the inlet to the outlet of the casing 1, the rotors 4 and 5 are rotated by the fluid pressure. At this time, the rotors 4 and 5 and the bearings 6 and 7 rotate while sliding on the outer peripheral surfaces of the support shafts 9 and 10. On the other hand, the driven magnet 14 is attracted to the driving magnet, rotates together with the rotation transmission shaft 12 without a phase difference with respect to the rotation of the rotors 4 and 5, and transmits the rotation to the counter.

However, in the prior art,
A driving magnet 8 made of a fragile material such as ferrite is buried in the bearing 6 made of carbon material so as to be flush with the outer peripheral surface of the bearing 6.
When press-fitting the bearing 6 into the center hole 4A of the rotor 4,
Stress strain and impact are applied to the driving magnet 8,
There is a drawback that the main drive magnet 8 is easily damaged. For this reason, the work takes a long time and is likely to cause defects. In addition, in a flow meter that measures corrosive fluids such as chemical liquids and food fluids, if there is a gap between the center hole 4A and the bearing 6,
There was a drawback that corrosive fluid entered through the gap and corroded the main drive magnet 8 itself.

The present invention aims to improve the drawbacks of the above-mentioned prior art, and its feature is that the entire circumference of the driving magnet is molded into the center hole of one of the pair of rotors. A ring-shaped synthetic resin body is fixed thereto, and a pair of bearings are fixed on both sides of the synthetic resin body, and at least one of the two support shafts is formed by a hollow shaft, and the hollow shaft One of the rotors is rotatably supported by inserting the synthetic resin body and a bearing into the hollow shaft, and a rotation transmission shaft disposed in the hollow shaft has a rotation transmitting shaft that follows the rotation of a driving magnet embedded in the synthetic resin body. By providing a driven magnet that rotates with the main drive magnet, the synthetic resin body and bearing can be press-fitted into the center hole separately, and corrosion is prevented by molding the entire circumference of the main drive magnet with synthetic resin. The present invention provides a positive displacement flowmeter that can perform

Hereinafter, the present invention will be described together with the embodiments shown in FIGS. 2 to 4. Constituent elements that are the same as those of the prior art shown in FIG.

Reference numeral 21 denotes an annular synthetic resin body fixed to the center hole 4A of the rotor 4 by press-fitting means, and the synthetic resin body 21
Grooves 21A, 21A,
... is formed, and the inner peripheral side thereof forms a support shaft insertion hole 21B having a slightly larger diameter than the outer diameter of the support shaft 9. Here, the synthetic resin body 21 is made of, for example, phenol resin, polypropylene resin, vinyl chloride resin, or the like. 22 is the synthetic resin body 2
The magnet 22 is a main drive magnet that is molded so that its entire circumference is covered within the synthetic resin body 2.
1 is molded at the same time as resin molding. 2
Reference numerals 3 and 24 denote annular bearings fixed in the center hole 4A of the rotor 4 by press-fitting means. , 24 support shaft insertion hole 2
A support shaft 9 is inserted through 3A and 23B, and the rotor 4 is rotatably supported with respect to the support shaft 9.

Although the present invention is configured as described above, the center hole 4A
The bearing 23, the synthetic resin body 21, and the bearing 24 may be press-fitted in this order and fixed. vice versa,
The synthetic resin body 21 may be press-fitted first, and then the bearings 23 and 24 may be press-fitted from both sides thereof. At this time, a driving magnet 22 is molded into the synthetic resin body 21, and since the entire circumference of the magnet 22 is covered and can be press-fitted separately from the bearings 23 and 24, a light external force is required. It can be press-fitted, and therefore damage caused by impact, stress strain, etc. during press-fitting can be prevented. In particular, since grooves 21A are formed all around the outer periphery of the synthetic resin body 21, the protrusions between the grooves 21 deform toward the respective grooves 21 during the press-fitting operation, and the press-fitting operation can be carried out with a light external force. This can reliably prevent damage to the driving magnet 22, and also prevent the synthetic resin body 21 from rattling as the protrusion is in close contact with the center hole 4A in the crushed state. Furthermore, since the main drive magnet 22 is entirely covered with resin that can withstand corrosive fluids, there is no fear of corrosion.

In the above embodiment, elliptical gear type rotors are used as the rotors 4 and 5, but roots type rotors may also be used.
Further, although it has been described that only one of the support shafts 9 and 10 is a bottomed hollow shaft, it may be a cylindrical body that opens to the outside from the lid body 1B side. Since the inside of the chamber 11 communicates with the outside air, the cooling effect can be enhanced. moreover,
Of course, the other support shaft 10 may also be a hollow shaft or may be a cylindrical body opened to the outside from the lid 1B side.

As described in detail above, the positive displacement flowmeter according to the present invention has a structure in which the active magnet is molded in a synthetic resin body, and bearings are provided on both sides of the synthetic resin body with respect to the center hole of the rotor. Therefore, the following effects can be achieved.

The main drive magnet is covered all around in a synthetic resin body, and the synthetic resin body can be press-fitted into the center hole separately from the bearing, so press-fitting can be done with a light external force, preventing damage to the main drive magnet. sell.

The active magnet is molded all around, so there is no risk of corrosion.

As a result of the above, productivity can be improved, the defect rate can be reduced, and the yield can be increased.

By forming grooves on the outer circumferential surface of the synthetic resin body, the protrusions between each groove are easily deformed during press-fitting, allowing for press-fitting with less force, and the protrusions are crushed and tightly contact the center hole. , it is possible to reliably prevent the occurrence of backlash in the active magnet.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a positive displacement flowmeter according to the prior art, FIGS. 2 to 4 show a positive displacement flowmeter according to the present invention, and FIG. 3 is a sectional view taken in the direction of the - arrow in FIG. 2, and FIG. 4 is a perspective view of the synthetic resin body and the bearing. 1... Casing, 3... Measuring chamber, 4, 5...
Rotor, 4A, 5A...center hole, 9, 10...support shaft, 12...rotation transmission shaft, 14...driven magnet, 21...synthetic resin body, 21A...groove, 22
...Driver magnet, 23, 24...Bearing.

Claims (1)

[Scope of utility model registration request] A casing having a metering chamber between an inlet and an outlet; a pair of rotors provided in the metering chamber and rotating in proportion to the flow rate of the fluid to be measured; In a positive displacement flowmeter consisting of two support shafts provided in the casing to rotatably support each rotor, the center hole of one of the pair of rotors has the entire drive magnet. A ring-shaped synthetic resin body having a molded circumference is fixed, and a pair of bearings are fixed across the synthetic resin body, and at least one of the two support shafts is formed by a hollow shaft. The synthetic resin body and the bearing are inserted into the hollow shaft to rotatably support one rotor, and the rotation transmission shaft disposed within the hollow shaft has a main drive embedded in the synthetic resin body. A positive displacement flowmeter equipped with a driven magnet that rotates as the magnet rotates.