JPH0344644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to the structure of a liquid level meter installed in a liquid storage tank such as a fuel tank.

(Prior Art) A liquid level meter 50 having a structure shown in FIG. 12 has been known as a liquid level meter for detecting the liquid level of fuel contained in a fuel tank.

This liquid level meter 50 includes a tightly wound portion 53 of a coil 52 formed at the upper end of a rod-shaped core 51 made of ferrite, and a loosely wound coil 52 formed on the core 51 adjacent to the tightly wound portion 53. portion 54 and the tightly wound portion 5
3 and the loosely wound portion 54 are inserted into the casing 55, and the loosely wound portion 5 of the casing 55
The liquid level 5 is
7 and a conductor ring 58 floating on top of the conductor ring 58.

(Problems to be Solved by the Invention) However, the liquid level meter 50 having the above structure has the following problem.

That is, depending on various factors such as the height of the fuel tank 61 and the way in which the liquid level meter 50 is attached, it may be necessary to provide a liquid level meter 50 in which only the length of the guide portion 56 is different.

However, in the casing 55, the guide portion 56 and the head portion 60 in which the tightly wound portion 53 is built in above the guide portion 56 are molded simultaneously and integrally by, for example, injection molding. , when attempting to industrially produce the casing 55 in which the length of the guide portion 56 is changed,
There is a problem in that various molding molds must be prepared depending on the length of the guide portion 56. This results in an increase in the cost of the product due to the manufacture of various molding dies, and also leads to the problem of complicating the management of the dies.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid level meter having a structure that can solve the above-mentioned problems.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned object, the present invention provides a casing having a tightly wound portion of the coil formed around the core and a similarly formed loosely wound portion. The liquid level meter is composed of a head part in which the tightly wound part is built-in and a guide part in which the loosely wound part is built in, and the head part is integrally molded with a pre-formed guide part. This configuration is adopted.

(Function) A portion to become a guide portion is formed in advance from pipes etc. cut into various lengths, and a head portion is integrally molded at one end thereof. This makes it possible to mold casings with guide portions of various lengths by using only one mold for forming the head portion. A tightly wound portion and a sparsely wound portion of the coil formed at one end of the core are inserted into these casings. When the conductor ring into which the guide portion is loosely inserted is set, liquid level gauges of various lengths are formed. When the level gauge is installed in a liquid tank of corresponding length, it works as well as a level gauge using a conventionally manufactured casing.

(Example) Next, an example in which the present invention is embodied in a liquid level meter installed in a fuel tank will be described based on FIGS. 1 to 6.

A liquid level gauge 3 is attached to an upper member 2 of a fuel tank 1 serving as a liquid storage tank in which fuel L is accommodated. The liquid level meter 3 includes a rod-shaped core 4 formed by winding a silicon steel plate with a thickness of about 0.1 mm on both sides electrically into a roll, and a coil 5b formed by winding a conducting wire 5a around the core 4.
and a casing 6 in which the coil 5b is built-in,
It mainly consists of a conductor ring 8 that floats up and down along the casing 6 in response to fluctuations in the liquid level 7 of the fuel L.

The core 4 consists of a densely wound part 9 in which the conducting wire 5a is tightly wound, and a sparsely wound part 10 in which the conductive wire 5a is loosely wound.The former is formed at the upper end of the core 4, while the latter is formed in the remaining portion of the core 4.

The casing 6 has a head part 11 in which the tightly wound part 9 is built-in, and a guide part 1 in which the loosely wound part 10 is built in.
A stopper 13 is fixed to the lower end of the loosely wound portion 10 to close the end in a liquid-tight manner and to prevent the conductor ring 8 from falling off.

Further, the diameter of the head portion 11 is larger than that of the loosely wound portion 10, so that even if the liquid level 7 rises to the level of the head portion 11, the rise of the conductive ring 8 will not occur.
Stop at the lower end of 1.

In addition, in order to be able to detect the liquid level of the fuel L stored in the fuel tank 1 when it is almost full, the head portion 11 is made to protrude from the upper member 2, and the conductor ring 8 is attached to the upper member of the fuel tank 1. The structure can be changed so that it can rise along the guide part 12 to the lower surface of the guide part 2.

In this embodiment, both the head part 11 and the guide part 12 are made of synthetic resin, specifically, polylauramide (nylon 12), and furthermore,
The guide portion 12 is molded before the head portion 11 is formed by cutting the pipe 14 to a predetermined length. The head portion 11
is obtained by a so-called integral molding method, in particular, an insert molding method, in which nylon 12 is melted and molded onto one end of the guide portion 12, and at the same time the molded head portion 11 is adhered to the guide portion 12. It is something. Therefore, in the present invention, when the head portion 11 is integrally molded with the guide portion 12,
Synthetic resins with good bonding properties are used in combination to bond the two.

Specifically, to describe the method of manufacturing the casing 6, first, as shown in FIG. 2, a pipe 14 for forming the guide portion 12 is formed by extrusion from nylon 12. This pipe 14 is cut to the length of the guide part 12, taking into account the joining margin for the head part 11, and the end thereof is inserted into the head part molding die 15 as shown in FIG. Then, molten nylon 12 is injected into the cavity C formed in the shape of the head part 11 through the gate 16, and the head part 11 is insert-molded. The head molding die 15 used in this embodiment is composed of a lower mold 17 and an upper mold 18 which is stacked on the lower mold 17 to form the cavity C, and the lower mold 17 has two parts at the front and rear. It is becoming divided. The lower mold 17
An insertion hole 19 into which the end of the pipe 14 can be inserted is formed in the upper mold 18 to prevent the end from being blocked by the resin during insert molding. A plug portion 20a having an outer diameter substantially the same as the inner diameter of the hole 14 is formed.

After the injection of the resin into the cavity C is completed, when the mold is released, the fourth mold is removed from the head molding die 15.
As shown in the figure, a molded product is obtained in which the head portion 11 is integrally molded onto the pipe 14.

Next, as shown in FIG. 5, a handle 21a is formed at the base end of the pipe 14 in the molded product, a closed portion 21b with an enlarged diameter is formed at the distal end, and furthermore, the pipe 14 in the molded product is formed with a handle 21a at the base end and a closed section 21b with an enlarged diameter at the distal end. A plug member 21 having a large length is inserted from the head 11 side to close the other end of the pipe 14, and at the same time, the conductor ring 8 is inserted from the other end.

The conductor ring 8 is made of a magnetic material, and a floating body 22 such as a foamed resin is attached around the conductor ring 8, so that the conductor ring 8 can float on the liquid level 7 of the fuel L.

After the conductor ring 8 is inserted, the end of the pipe 14 is set in the stopper mold 23.

This stopper mold 23 has the stopper 1
It is composed of a lower mold 24 provided with a concave portion having the shape of 3, and an upper mold 25 that is overlapped with the lower mold 24 to form a cavity D. The upper mold 25 is divided into two parts, front and rear. It's getting old. The upper mold 2
5 also has an insertion hole 26 into which the end of the pipe 14 can be inserted.
A gate 29 for injecting resin is also provided.

After the end of the pipe 14 is inserted into the stopper mold 23, a molten nylon 12 is injected into the cavity D. If the molded product is removed from the stopper mold 23 after being released from the mold, a casing 6 in which the conductor ring 8 is loosely inserted into the guide portion 12 is obtained as shown in FIG.

A core 4 having a tightly wound part 9 and a loosely wound part 10 is inserted into the casing 6 as shown in FIG. 1, and the upper outer periphery of the casing 6 is locked to the upper member 2 of the fuel tank 1. .

Then, the conductive wire 5a is connected to, for example,
The liquid level 7 of the fuel tank 1 can be detected by connecting it to a meter or other liquid level indicator via the L-V conversion circuit and output correction circuit (both not shown) disclosed in Publication No. 253920. become.

Next, to describe the function and effect of this embodiment, the guide portion 1 formed as a pipe 14 in advance
2 as an insert member, this is set in the head molding mold 15, and insert molding is performed to form the head portion 11, and the head portion 11 is joined to the guide portion 12. Therefore, when producing this liquid level meter 3 industrially, it is necessary to prepare guide parts 12 of various lengths, and then prepare one head part molding die 15 to mold the head part 11. For example, it becomes possible to manufacture liquid level meters 3 equipped with guide portions 12 having various lengths. As a result, fuel tanks 1 of various depths
It is possible to manufacture a liquid level meter 3 applicable to Therefore, the increase in product cost caused by the manufacturing cost of the head molding die 15 and the management cost of the die is eliminated.

The present invention is not limited to the above embodiments, but
For example, it can also be implemented in the following manner.

(1) As long as the fuel L does not enter the casing 6, there is no need to provide the stopper 13 on the guide portion 12. Methods of closing one end of the pipe 14 or forming the stopper 13 at the one end include welding a hot plate, melt-bonding while rotating the closing member, spin welding, and using an adhesive. Various methods can be adopted.

(2) When forming the stopper 13, the stopper 1
3 can be insert molded prior to molding the head portion 11. In addition, as shown in FIG. 7, two pipes 14 that will become the guide part 12 are prepared, one of which is used as an insert for molding the head part 11, and the other one is used as an insert for molding the stopper 13. It is also possible to mold using the simultaneous molding die 28. In this embodiment, by reversing the pipe 14 and performing molding again using the simultaneous molding die 28, two casings 6 are produced simultaneously.

(3) Core 20 of the upper mold 18 used in the above example
The pipe 14 may be separated from the upper mold 18 as shown in FIG. 8, the pipe 14 may be temporarily closed with its closing portion 20a, and then they may be set in the head molding die 15 as shown in FIG.

(4) As shown in Figures 10 and 11, the upper mold 18,
25. Insert molding can also be performed by configuring the lower molds 17 and 24 so that the pipe 14 is inserted horizontally.

(5) In addition to the injection molding method, the head portion 11 can also be molded by a blow molding method, a monomer casting method, a RIM molding method, or the like.

(6) The liquid level gauge 3 measures various liquids in addition to fuel L.
For example, it can be used to detect the liquid level of water, chemicals, etc.

(7) By directly supporting the liquid level gauge 3 on the lower member 27 of the fuel tank 1 shown in FIG. However, by displacing the liquid level meter 3 downward together with the lower member 27, the error in detecting the liquid level can be reduced.

Effects of the Invention As detailed above, the present invention has a structure in which the head portion of the casing is integrally molded and joined to the pre-formed guide portion, so that it is easy to use when industrially producing liquid level meters. As long as guide portions having various lengths are prepared, a liquid level meter that can be applied to various liquid storage tanks can be produced using a single molding die, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of the embodiment installed in the fuel tank, Fig. 2 is a partially longitudinal side view of the pipe formed in the guide part, and Fig. 3 is a longitudinal cross-sectional view showing the forming process of the head part. 4 is a partial longitudinal sectional view of the casing, FIG. 5 is a longitudinal sectional view showing the stopper forming process, FIG. 6 is a longitudinal sectional view of the casing, and FIG. 7 is a longitudinal sectional view of the casing.
The figure is a partial vertical sectional view showing the process of simultaneously molding the head part and the guide part, FIG. 8 is a partial vertical sectional view showing the preparation process for forming the head part in a different manner, and FIG. Fig. 10 is a longitudinal sectional view showing another form of the head mold, and Fig. 11 shows another form of the stopper mold. longitudinal section,
FIG. 12 is a longitudinal sectional view showing the prior art. 1...Liquid storage tank, 3...Liquid level meter, 4
...Core, 5b...Coil, 6...Casing, 7...Liquid level, 8...Conductor ring, 9...Tightly wound part, 10...Losely wound part.

Claims (1)

[Claims] 1. A casing 6 having a tightly wound portion 9 of a coil 5b formed around the core 4 and a similarly formed loosely wound portion 10, and a casing 6 on the outer peripheral side of the loosely wound portion 10. In the liquid level meter 3, the casing 6 is connected to a head part 11 in which the tightly wound part 9 is built in, and a conductive ring 8 that can float in the liquid storage tank 1 along 1. A liquid level meter comprising a guide part 12 having a built-in head part 11 and a head part 11 integrally formed with the guide part 12 formed in advance. 2. The liquid level meter according to claim 1, wherein the guide portion 12 is obtained from a pipe 14. 3. The liquid level meter according to claim 1, wherein the head portion 11 and the guide portion 12 are made of synthetic resin, and the guide portion 12 is obtained from the pipe 14. 4. The liquid level meter according to claim 3, wherein the synthetic resin is polyamide.