JPH082577Y2 - Volumetric flow meter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shaft structure of a rotor that rotates according to a flow rate in a measuring chamber, and more particularly to a positive displacement flow meter that can be easily fixed by a shaft and can be provided at low cost.

2. Description of the Related Art As is well known, a volumetric flowmeter has a rotor that rotates in proportion to the flow rate in a measuring chamber that is bored in a main body inserted in a pipe through which a fluid to be measured flows, and that is small between the rotor and the measuring chamber. It is rotatably supported with a gap, and detects the rotation of the rotor to display the flow rate. Conventionally, for example, the structure shown in FIG. 4 was used. The volumetric flowmeter of FIG. 4 is a cross section of the main body interposed in the pipe as seen from a plane orthogonal to the pipe, and the dotted circle 100 is the inflow or outflow port. In the figure, 1
Is an outer casing of the main body, and a measuring chamber 10 is provided therein. Weighing room 10
Communicates with the inflow / outflow port 100 and forms a recess. 2,2
Are a pair of rotor shafts having the same diameter and having a collar 21 at one end, and a bolt 22 is formed on the outer wall surface of the main body casing 1 at the collar 21.
Is screwed on. The shaft portion of the cylinder penetrates the bottom portion of the measuring chamber 10 of the main body outer casing 1 and is arranged in parallel in the measuring chamber 10. 3 and 3 are a pair of rotors, which are shown as non-circular gears in the figure.
32 is a tooth which meshes with each other of the non-circular gear. Reference numeral 31 denotes a bearing, which is fitted in the center of rotation of the rotor 3 and is rotatably supported by the rotor shafts 2, 2. The rotors 3, 3 rotate with a minute gap between them and the inner wall of the measuring chamber 10. Reference numeral 4 denotes a lid of a concave portion of the measuring chamber 10, through which shaft holes 41, 41 into which the cylindrical ends of the rotor shafts 2, 2 are inserted, are fixed by a positioning pin 5 with the main body outer casing 1. It
Reference numeral 6 denotes a rear lid, which is liquid-tight by an O-ring 8 and screwed to the main body outer casing 1 by a bolt 7. Reference numeral 9 denotes an outer casing of a counting unit, which houses a counting unit (not shown) that detects the rotation of the rotor and displays the flow rate.

Problems of Prior Art In the conventional volumetric flow meter described above, the rotor shaft 2 is fixed to the main body outer casing 1 at the collar 21, but the shaft structure having the collar 21 is large in material and cannot be made inexpensive. Since the end face plate 4 fits and holds the shaft end of the rotor shaft 2, there is a slight gap between the rotor shaft 2 and the shaft hole 41, and liquid leakage occurs. There was a problem that the lid 6 had to be liquid-sealed by the O-ring 8, which was expensive.

Means for Solving Problems The present invention has been made in view of the above problems, and an inexpensive positive displacement flow meter from the viewpoint of material and assembly time by simplifying the shaft structure and facilitating assembly. The purpose of this is to provide rotation of a pair of rotors that rotate according to the flow rate around a rotor shaft that is fixed in a measuring chamber that is bored in the main body through which the fluid to be measured flows. In a volumetric flow meter that detects the flow rate from a cylinder, a rotor shaft with a rotation-preventing pin eccentrically embedded in one end face of a cylinder with a constant diameter is bored in the end face of the main body of the measuring chamber, and a shaft is provided on the bottom face of this shaft hole. Fits into the hole and an eccentric hole that is eccentrically provided, and the rotation-preventing pin is rotationally fixed so that it comes into pressure contact with the eccentric hole, and the other end of the rotor shaft is screwed to the main body in a liquid-tight manner and weighed. Fix the rotor shaft by inserting it into the shaft hole that is formed in the rear lid that forms the end face of the chamber. It fixes the rotor shaft.

Example FIG. 1 is a sectional view showing a volumetric flow meter of the present invention, which is a sectional view taken along a plane orthogonal to a pipe, similar to the volumetric flow meter of FIG. 4, and is similar to the case of FIG. 4 in the figure. Constituent elements that operate are given the same reference numerals as in FIG. 4 and their explanations are omitted. In the figure, 20 is a rotor shaft, which is a cylinder having a uniform cross section, and one end face of which is eccentrically embedded with a detent pin 22. An eccentric pin hole 13 (see FIG. 2) is formed in the other end surface. 2 is an enlarged detail of the shaft structure in the cross section of FIG. 1, and FIG. 2 (b) shows a cross section taken along the line XX (when the rotor 20 is removed).
A shaft hole 11 having a predetermined depth for inserting the rotor shaft 20 is bored on the bottom surface of the measuring chamber 10 of the main body outer casing 1, and further an eccentric hole 12 eccentric by a distance d is formed on the bottom surface of the shaft hole 11. You are sitting down. 60
The rear cover is provided with a shaft hole 61 into which the other end of the rotor shaft 20 is inserted, and a pin hole 62 for positioning and a bolt hole 63 for screwing the rear cover 60 to the main body outer casing 1 with a bolt 7 are formed. Penetrates. In the above-described volumetric flow meter of the present invention, the shaft 20 is fixed to the main body outer casing 1 by using the shaft mounting jig 30 shown in FIG. The shaft mounting jig 30 is one in which a pin 16 is embedded in a position of a pin hole 13 at the bottom of the recess 15 of a column 14 having a recess 15 having an inner diameter into which the rotor shaft 20 is fitted and which is bored on the end surface. In the shaft mounting jig 30, the recess 15 is inserted into the end of the rotor shaft 20 and the pin 16 is inserted into the pin hole 13. At this time, the detent pin is placed at the position A of the eccentric hole 12. Then, the rotor shaft 20 is rotated in the arrow R direction. Since the rotor shaft 20 is constrained in the shaft hole 11, at the position B, the rotation stop pin 22 has the eccentric hole 12
Is pressed against. At this time, the rotor shaft 20 tilts within the range of the shaft hole 11 but is fixed in a two-sided manner by the shaft holes 61, 61 positioned by the positioning pin 5 of the rear lid 60.
Since the shaft holes 61, 61 and 11, 11 eccentric holes 12, 12 do not penetrate the rear lid 60 and the main body outer casing 1, the end face plate 4 is unnecessary. In this case, the rotation of the rotor 3 is performed by, for example, a magnetic sensor or the like (not shown) arranged in the outer casing 1 of the main body so that the magnetic flux of the transmitting magnet embedded in the end surface of the rotor 3 faces the magnet. It is detected without contact.

Effect According to the above-mentioned volumetric flow meter of the present invention, the rotor shaft 20 has a shaft hole.
The rotation prevention pin 22 is fixed in the eccentric hole 12 by pressing in the eccentric hole 12 by a simple operation.
Is a cylinder having a constant outer diameter, and the end face plate 4 is not required, so that an inexpensive volumetric flow meter can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view in a plane orthogonal to the flow of the volumetric flow meter of the present invention, FIG. 2 is a detailed view of a shaft structure, FIG. 3 is a shaft mounting jig, and FIG. 4 is a conventional volume. A cross-sectional view of the flow meter is shown. 1 …… Main body outer case, 2,20 …… Rotor shaft, 3 …… Rotor, 4
…… End plate, 6,60 …… Rear lid, 11,41,61 …… Shaft hole, 12 ……
Eccentric hole, 22 …… Anti-rotation pin.

Claims (2)

[Scope of utility model registration request] 1. A positive displacement flowmeter for detecting a flow rate from the rotation of a pair of rotors that rotate in accordance with the flow rate around a rotor shaft fixed in a measuring chamber formed in a main body through which a fluid to be measured flows. , A shaft hole in which a rotation prevention pin is eccentrically embedded and embedded in one end face of a cylinder with a constant diameter in the end face of the main body of the measuring chamber, and an eccentric hole eccentrically formed in the bottom face of the shaft hole. It is inserted into the hole, and the anti-rotation pin is rotatably fixed so as to come into pressure contact with the eccentric hole, and the other end of the rotor shaft is screwed into the main body in a liquid-tight manner and is drilled in the rear lid that forms the end face of the measuring chamber. A volumetric flowmeter, characterized in that the rotor shaft is fixed by being inserted into an established shaft hole. 2. A jig for punching a pin hole at an axially eccentric position on an end surface of a rotor shaft which does not have a whirl-stop pin and engaging the pin hole to rotate the rotor shaft. The shaft fixing jig for a volumetric flow meter according to claim 1, wherein a concave portion having an inner diameter slightly larger than a rotor shaft diameter is formed on an end surface of the body, and a pin is embedded in the bottom surface of the concave portion so as to be eccentric.