JP3640539B2 - Flow detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flow rate detector for detecting a flow rate of a fluid.
[0002]
[Prior art]
In general, a flow rate detector is provided with a flow straightening blade for rotating the flow of the fluid in a pipe for flowing the fluid, and the rotational speed of the impeller including the magnetic material is changed according to the flow rate of the fluid. The flow rate of the fluid is detected by providing a magnetism detecting means disposed on the downstream side of the rectifying blades so as to be freely rotatable and for detecting a change in the magnetic field caused by the rotation of the impeller.
[0003]
In order to rotatably support a shaft rod that serves as a rotating shaft of such an impeller, bearings are required at both front and rear ends thereof. Therefore, the upstream bearing is formed in the central portion of the rectifying blade, and the downstream bearing has a bearing member fixedly disposed in the pipe.
[0004]
[Problems to be solved by the invention]
In the conventional structure as described above, the downstream bearing member is a part that functions only as a bearing. Therefore, if it can be formed integrally with a pipe or the like instead of being configured as an independent part, the part cost and assembly cost are reduced. Both can be reduced.
[0005]
However, since the conventional shaft rod is made of metal such as stainless steel, for example, it is necessary to form the bearing member with a material having very good lubricity in order to prevent the bearing member from being worn out at an early stage. For this reason, the bearing member needs to be a separate part from the pipe, and the configuration as described above has to be taken.
[0006]
Then, an object of this invention is to provide the flow rate detector which can implement | achieve the reduction of the components cost concerning the bearing of an impeller, and an assembly cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a flow rate detector according to the present invention includes a flow rectifying blade for rotating a flow of fluid in a pipe for flowing a fluid, and an impeller including a magnetic material. A magnetism detecting means is provided on the outside of the pipe for detecting a change in the magnetic field caused by the rotation of the impeller, which is rotatably arranged downstream of the rectifying blade so that the rotation speed changes according to the flow rate. In the flow rate detector, a shaft rod that is a rotating shaft of the impeller is formed of a plastic material having good lubricity, and a first bearing that rotatably supports one end side of the shaft rod is integrated with the pipe. It is formed.
[0008]
The pipe and the first bearing may be integrally formed of a structural plastic material, and a second bearing that rotatably supports the other end of the shaft rod is provided at the central portion of the rectifying blade. It may be formed. The rectifying blades may be formed of a structural plastic material.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a flow rate detector according to a first embodiment of the present invention. Reference numeral 1 denotes a pipe through which water or other fluid flows, and is formed in a pipe line bent at a right angle by molding using a structural plastic material such as PPS (polyphenylene sulfide).
[0010]
In the pipe 1, an impeller 2 in which a plurality of blades project radially from an axial position is disposed so as to be rotatable around a shaft rod 3. In the impeller 2 of this embodiment, as shown in the side view of FIG. 2, four flat blades are projected in parallel with the axis at intervals of 90 °.
[0011]
The impeller 2 is molded with a plastic material mixed with magnetic powder. On the other hand, the shaft rod 3 is made of a plastic material having good lubricity, such as a fluororesin or a polyacetal resin, and is fitted into the axial position of the impeller 2 by press-fitting or the like in a state protruding from both sides of the impeller 2. It is fixed.
[0012]
Reference numeral 4 denotes a rectifying blade disposed on the upstream side of the impeller 2. In this embodiment, seven screw-like blades twisted around the axis are shown in the side view of FIG. 3. Are formed radially at equal intervals.
[0013]
As shown in the front view of FIG. 4, the outer edge portions of the seven blades are connected in an annular shape and are attached to the tips of the foot pieces 4 a protruding from three locations toward the downstream side. A claw 4b is projected. In this embodiment, these are integrally formed with the rectifying blade 4 by molding using a structural plastic material such as PPS.
[0014]
The rectifying blade 4 is fitted into the pipe 1 while elastically deforming the foot piece 4a, and when the engaging piece 4b is engaged with the stepped portion in the pipe 1, the foot piece 4a returns to its natural state by its own elasticity. As shown in FIG. 1, the foot piece 4a is fixed in the pipe 1 in a state in which the foot piece 4a is prevented from coming off.
[0015]
A shaft hole 5a (second bearing) is formed in the shaft portion 4c of the rectifying blade 4 from the downstream side in accordance with the axial position of the pipe 1, and the upstream end portion of the shaft rod 3 is formed in the shaft hole 5a. It is rotatably inserted.
[0016]
On the downstream side of the impeller 2, for example, three stays 1 a project from the pipe 1 toward the center axis position as shown in FIG. 5, which is a VV sectional view. The stay 1a is molded integrally with the pipe 1, and a shaft hole 5b (first bearing) is formed in the central shaft portion from the upstream side as shown in FIG. The downstream end is rotatably inserted into the shaft hole 5b.
[0017]
As described above, the shaft hole 5b that pivotally supports one end of the shaft rod 3 is formed of a plastic material integrally with the pipe 1. However, since the shaft rod 3 is formed of a material having good lubricity, the shaft hole 5b is formed. Wear is small and can be used continuously for a long time.
[0018]
A magnetic detector 6 using a Hall element or the like is disposed on the outer surface portion of the pipe 1 so as to be aligned with the impeller 2, and a change in the magnetic field caused by the rotation of the impeller 2 can be detected. It should be noted that the thickness of the pipe 1 is thin at the portion where the magnetic detector 6 is disposed.
[0019]
In the flow rate detector configured as described above, the flow of the fluid in the pipe 1 is rotated by passing through the rectifying blades 4, thereby rotating the impeller 2. Since the rotation speed corresponds to the flow rate of the fluid, the flow rate of the fluid flowing in the pipe 1 can be detected by calculating the rotation speed of the impeller 2 from the output signal from the magnetic detector 6.
[0020]
FIG. 6 shows a flow rate detector according to a second embodiment of the present invention, in which a stay 1 similar to that of the first embodiment is formed integrally with a straightly formed pipe 1 and its central shaft portion is shown. Further, a shaft hole 5b that pivotally supports one end of the shaft rod 3 is formed. As described above, the present invention is not limited to the above-described embodiment, and various embodiments can be employed.
[0021]
【The invention's effect】
According to the present invention, the first bearing that rotatably supports one end side of the shaft rod, which is the rotating shaft of the impeller, is formed integrally with the pipe, thereby reducing the component cost and assembly cost related to the impeller bearing. Since the shaft rod which becomes the rotating shaft of the impeller is formed of a plastic material with good lubricity, the wear of the bearing is small and long-term durability is obtained.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a flow rate detector according to a first embodiment of the present invention.
FIG. 2 is a side view of the impeller according to the first embodiment of the present invention.
FIG. 3 is a side view of the rectifying blade according to the first embodiment of this invention.
FIG. 4 is a front view of the rectifying blade according to the first embodiment of this invention.
FIG. 5 is a cross-sectional view taken along line VV in FIG. 1 according to the first embodiment of the present invention.
FIG. 6 is a front sectional view of a flow rate detector according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piping 1a Stay 2 Impeller 3 Shaft rod 4 Rectification blade 5a Shaft hole (2nd bearing)
5b Shaft hole (first bearing)

Claims (4)

A rectifying blade for rotating the fluid flow is arranged in a pipe for flowing the fluid, and the impeller including the magnetic material is rotatable so that the rotational speed changes in accordance with the flow rate of the fluid. In a flow rate detector disposed on the downstream side of the rectifying blades and provided with magnetic detection means on the outside of the pipe for detecting a change in the magnetic field caused by the rotation of the impeller,
The shaft rod, which is the rotating shaft of the impeller, is formed of a plastic material having good lubricity, and a hook-shaped protrusion is formed to protrude near the downstream end of the shaft rod so that the shaft rod is the blade A flow rate detection characterized in that a first bearing that is press-fitted from a downstream side into a hole formed in a vehicle axial position and rotatably supports a downstream end portion of the shaft rod is formed integrally with the pipe. vessel. The flow rate detector according to claim 1, wherein the pipe and the first bearing are integrally formed of a structural plastic material. The flow rate detector according to claim 1, wherein a second bearing that rotatably supports the other end side of the shaft rod is formed at a central portion of the rectifying blade. 4. The flow rate detector according to claim 3, wherein the rectifying blade is formed of a structural plastic material.

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