JP2003004509A - Liquid level sensor and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level sensor for enabling assembly of even a level sensor wherein the internal surface of an armholder with a U-shaped cross-section is provided with a protruding and recessed fitting section for maintaining turning stability, without breaking up the armholder, and its assembling method. SOLUTION: In the liquid level sensor, a bearing recessed section 4b2 used for maintaining turning stability is protrusively-installed from an upper surface of a lower support 4b on a float arm 3 with U-shaped cross-section toward a bypassing section 4d. Moreover, a frame inserting section 2a, which is thinner than the shortest distance between an upper end section and an upper support 4a of the bearing recessed section 4b2, is formed against an end section of a frame 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level sensor equipped with a float arm that rotates in accordance with the liquid level and a method for assembling the same, and more particularly, it has excellent rotational stability and flexibility in mounting location. And a method for assembling the same.

[0002]

2. Description of the Related Art Conventionally, there has been known a liquid level sensor having a rod-shaped float arm having a float attached at its tip, which float moves up and down according to the liquid level of fuel in a tank. FIG. 5 (A) is a plan view showing an example of a conventional liquid level sensor of this type, and FIG. 5 (B) is an enlarged sectional view of an essential part of the liquid level sensor shown in FIG. 5 (A).

A liquid level sensor 81 shown in FIGS. 5A and 5B is attached to, for example, a fuel tank of a vehicle, and includes a resin frame 82, a metal float arm 83, and a resin arm. It is configured to include a holder 84 and a float 86 having buoyancy with respect to the liquid to be measured.

The frame 82 is equipped with an electric circuit, such as a hall element 85c, for detecting the liquid level based on the rotation of the float arm 83 according to the fluctuation of the liquid level of the liquid to be measured. . In this frame 82,
An electronic device housing portion 82b that is open to the upper side is formed. The ring-shaped magnet 8 is provided in the electronic device housing portion 82b.
Hall element 85c as a magnetoelectric conversion element that detects the magnetic force from 5a and converts it into an electric signal, and this Hall element 8
A wiring board 85d on which 5c and the like are mounted is housed. The wiring board 85d is connected to an output terminal 5e for guiding the electric signal output from the hall element 85c to the outside. The electronic device housing portion 82b is filled with a molding material (not shown). The electric signal corresponds to the rotation angle of the float arm 83, that is, the liquid level. In addition, a core 85 as a magnetism collecting member is provided on the frame 82.
f is also attached.

Further, the frame 82 is an arm holder 8
4 has a concave cylindrical bearing portion 82a that is used at the time of mounting. A shaft hole into which the rotary shaft portion of the float arm 83 is inserted is formed in the central portion of the concave cylindrical bearing portion 82a.

The float arm 83 is in the form of a single metal rod, and comprises a rotary shaft portion serving as a fulcrum of rotation, and a rotary portion bent at a right angle to the rotary shaft portion. A cylindrical float 86 made of a material having buoyancy with respect to the liquid to be measured is attached to the tip of the rotating portion of the float arm 83.

The arm holder 84 holds the float arm 83 by an arm holding portion 84c and engages with the frame 82 to rotate the held float arm 83 with the rotary shaft portion as a fulcrum. The arm holder 84 has a convex cylindrical bearing portion 8 having a shape corresponding to the concave cylindrical bearing portion 82a of the frame 82.
4a. A shaft hole into which the rotary shaft portion of the float arm 83 is inserted is also formed in the center of the convex cylindrical bearing portion 84a.

When the liquid level sensor 81 is assembled,
First, the concave cylindrical bearing portion 82a and the convex cylindrical bearing portion 8 are formed.
4a is fitted and the frame 82 and the arm holder 84 are engaged with each other. Then, after inserting the rotating shaft portion of the float arm 83 into each shaft hole, the rotating portion of the float arm 83 is press-fitted into the arm holding portion 84c. This prevents the float arm 83 from falling off the frame 82. Further, the rotation of the float arm 83 is stabilized by fitting the concave cylindrical bearing portion 82a and the convex cylindrical bearing portion 84a.

A liquid level sensor 81 having such a structure
Is attached to a gasoline tank (not shown) that stores a liquid to be measured such as gasoline. Then, when the float 86 moves up and down due to the fluctuation of the liquid level, the float arm 83 rotates within the angular range θ1 with the rotary shaft portion as a fulcrum. Rotation within this angular range θ1 changes the magnetic force from the magnet 85a detected by the Hall element 85c, and an electric signal indicating the liquid level based on this change is taken out from the output terminal 5e.

However, since the gasoline tank is mounted by utilizing an empty space such as the rear portion of the vehicle, the shape thereof is various, and the frame 82 and the angle range θ1 as described above are used.
The liquid level sensor 81 having the above relationship may not be attached. For example, the frame 8 shown in FIG.
Float 86 to frame 8
In the case of a gasoline tank that can move up and down only on the right side of 2, that is, on the side opposite to the angle range θ1, the design must be changed to the liquid level sensor 91 as shown in FIG.

FIG. 6 (A) is a plan view showing another example of the conventional liquid level sensor, and FIG. 6 (B) is an enlarged cross-sectional view of the essential parts of the liquid level sensor shown in FIG. 6 (A). is there.

The liquid level sensor 91 shown here is shown in FIG.
With respect to the mounting position of the frame 82 shown in (A), the float 86 can move up and down on the right side of the frame 82, that is, in the range corresponding to the angular range θ2 opposite to the angular range θ1. However, this liquid level sensor 91
Structurally, the following structural problems occur.

[0013]

Problems to be Solved by the Invention FIGS. 6 (A) and 6 (B)
A liquid level sensor 91 shown in FIG. 2 is an electric circuit such as a frame 82, a float arm 83, a Hall element 85c mounted on the frame 82, similar to the liquid level sensor 81,
And float 86, and the liquid level sensor 81.
It is configured to include a resin arm holder 94 corresponding to the arm holder 84. The same applies to the action related to liquid level detection. Therefore, the duplicated description of the same parts as the liquid level sensor 81 will be omitted here, and only the different arm holder 94 will be described.

That is, the arm holder 94 of the liquid level sensor 91 is divided into an arm holder upper portion 94b and an arm holder lower portion 94c. A convex cylindrical bearing portion 94a equivalent to the convex cylindrical bearing portion 84a is formed on the arm holder lower portion 94c.

The reason why the arm holder upper portion 94b and the arm holder lower portion 94c are thus divided will be described with reference to FIGS. 6 and 7. 7A and 7B are explanatory views showing the problems of the liquid level sensor shown in FIG.
In particular, FIG. 7A shows a state before the arm holder is divided, and FIG. 7B is an explanatory diagram showing a state where the arm holder is divided.

The arm holder of the liquid level sensor 91 is mounted at the mounting position shown in FIG. 6A in order to secure the angular range .theta.2 in consideration of the extending direction of the float arm 83. It is necessary to form it in a U-shaped cross section as shown in B). With such a U-shaped cross section,
As shown in FIG. 7A, since the distance a1 between the upper end of the convex cylindrical bearing portion 94a of the arm holder 94 and the ceiling of the frame 82 is smaller than the height b1 of the frame 82,
Normally, the float arm 83 cannot be attached to the frame 82. Therefore, as shown in FIG. 7B, it becomes necessary to divide the float arm 83 into an arm holder upper portion 94b and an arm holder lower portion 94c.

As described above, in order to maintain the stability of the rotation of the float arm 83, in the liquid level sensor provided with the convex cylindrical bearing portion 94a fitted to the concave cylindrical bearing portion 82a, the above angle range To secure θ2, the arm holder upper portion 94b and the arm holder lower portion 94c are required.
The need to divide into comes out. That is, the number of parts increases, which causes an increase in manufacturing cost. Further, the division causes a decrease in strength of the arm holder and the liquid level sensor itself.

Therefore, in view of the above-mentioned present situation, the present invention also relates to a liquid level sensor provided with an uneven fitting portion on the inner surface of an arm holder having a U-shaped cross section for maintaining rotational stability. An object of the present invention is to provide a liquid level sensor which can be assembled without dividing an arm holder and an assembling method thereof.

[0019]

A liquid level sensor according to a first aspect of the present invention, which has been made to solve the above problems, has a rotating shaft portion 3a and this rotating shaft portion 3 as shown in FIGS.
The rod-shaped float arm 3 is formed by a rotating part 3b which is bent substantially at a right angle to a and rotates about the rotating shaft part 3a, and is attached to the tip of the rotating part 3b of the float arm 3. A float 6 having buoyancy with respect to the liquid to be measured, a frame 2 having an electric circuit for detecting the liquid level of the liquid to be measured based on the rotation of the float arm 3, and an upper surface of the frame 2. A cylindrical upper bearing tubular portion 2a2 having a frame portion rotary shaft hole 2a1 in the center thereof, which is provided in a projecting manner and through which the rotary shaft portion 3a is inserted,
The lower surface of the frame 2 is formed into a cylindrical shape that is hollowed out into an annular shape, and has a lower bearing cylindrical portion 2a3 that has the frame portion rotation shaft hole 2a1 at the center, and the lower bearing cylindrical portion 2a3 that sandwiches the frame 2 from above and below. An arm holder 4 having a U-shaped cross section including an upper holding part 4a and a lower holding part 4b formed in parallel, and a part of the upper holding part 4a,
A detour 4d formed so as not to obstruct the rotation of the float arm 3 and a detour 4d projecting from the upper surface of the lower holding part 4b toward the detour 4d. A bearing recess 4b2 having a cylindrical inner wall corresponding to 2a3 and having a holder portion rotation shaft hole 4b1 through which the rotation shaft portion 3a is inserted at the center, and a top surface portion of the upper holding portion 4a, The rotating portion 3b can be press-fitted from the upper side, and the arm holding portion 4c that holds the press-fitted rotating portion 3b, and the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion from the end portion of the frame 2. The frame insertion portion 2 which is a part of the frame 2 toward which the frame insertion portion 2 is thinner than the shortest distance a between the upper end portion of the bearing recess 4b2 and the upper holding portion 4a.
a, the lower bearing cylindrical portion 2a3 and the bearing recess 4b2 are fitted together, and the rotary shaft portion 3a is inserted through the frame rotary shaft hole 2a1 and the holder rotary shaft hole 4b1 to hold the arm. It is characterized in that the portion 4c holds the rotating portion 3b.

According to the first aspect of the present invention, in order to maintain the rotational stability, which is provided so as to project from the upper surface of the lower holding portion 4b of the U-shaped float arm 3 toward the bypass portion 4d. A bearing recess 4b2 to be used is provided. A frame insertion portion 2a, which is thinner than the shortest distance a between the upper end of the bearing recess 4b2 and the upper holding portion 4a, is formed toward the end of the frame 2. Therefore, the frame insertion portion 2a is provided with the bearing recess 4b2 when assembled.
Since it can pass between the upper holding part 4a and the upper holding part 4a,
The frame 2 can be sandwiched between the arm holders 4. As a result, the arm holder 4 can be assembled to the frame 2 without dividing the arm holder 4 unlike the conventional example.

A liquid level sensor according to a second aspect of the present invention, which has been made to solve the above-mentioned problems, is the same as the liquid level sensor according to the first aspect of the present invention, as shown in FIG. The side bearing cylindrical portion 2a3 is provided at a position deviated from the center of the frame 2, and the float arm 3 has the float 6 provided with the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion 2a3. It is characterized in that it is attached so as to rotate on the opposite side with the central portion sandwiched therebetween.

According to the second aspect of the present invention, the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion 2a3 are provided at positions deviated from the center of the frame 2, and the float arm 3 is different from this. It is attached so as to rotate in the opposite direction. As a result, the float arm 3 can rotate above the frame 2.

A liquid level sensor according to a third aspect of the present invention, which has been made in order to solve the above-mentioned problems, as shown in FIGS. 1 and 2, in the liquid level sensor according to the second aspect, the upper bearing cylindrical portion 2a2 is used. Is cylindrical, and the inner part of the bypass 4d is semicircular.

According to the third aspect of the present invention, since the upper bearing tubular portion 2a2 is cylindrical and the inner wall of the bypass portion 4d is semicircular, the assembly can be smoothly performed.

The liquid level sensor according to claim 4 made to solve the above-mentioned problems is, as shown in FIGS. 1 and 2, in the liquid level sensor according to claim 3, inside the bypass portion 4d. The part is characterized in that one end 4d1 which is in contact with the straight line portion has a semicircular shape like a heart-shaped half which is wider than the other end.

According to the fourth aspect of the present invention, the one end 4d1 which is in contact with the straight line portion has a semicircular shape which is half of a heart shape which is larger than the other end. Therefore, this open portion is used. Then, the upper bearing tubular portion 2a2 of the frame 2 is easily assembled.

In order to solve the above-mentioned problems, the liquid level sensor assembling method according to a fifth aspect of the present invention is, as shown in FIGS. 3 and 4, a rotary shaft portion 3a and the rotary shaft portion 3a.
And a rod-shaped float arm 3 formed by a rotating portion 3b that is bent at a substantially right angle with respect to the rotating shaft portion 3a and is attached to the tip end portion of the rotating portion 3b of the float arm 3. A float 6 having buoyancy with respect to the liquid to be measured, a frame 2 on which an electric circuit for detecting the liquid level of the liquid to be measured based on the rotation of the float arm 3 is mounted, and an upper surface portion of the frame 2. A cylindrical upper bearing tubular portion 2a2 having a frame portion rotary shaft hole 2a1 at the center thereof, which is provided in a protruding manner on the center of the frame, and the rotary shaft portion 3a is inserted therethrough;
The lower surface of the frame 2 is formed into a cylindrical shape that is hollowed out into an annular shape, and has a lower bearing cylindrical portion 2a3 that has the frame portion rotation shaft hole 2a1 at the center, and the lower bearing cylindrical portion 2a3 that sandwiches the frame 2 from above and below. An arm holder 4 having a U-shaped cross section including an upper holding part 4a and a lower holding part 4b formed in parallel, and a part of the upper holding part 4a,
A detour 4d formed so as not to obstruct the rotation of the float arm 3 and a detour 4d projecting from the upper surface of the lower holding part 4b toward the detour 4d. A bearing recess 4b2 having a cylindrical inner wall corresponding to 2a3 and having a holder portion rotation shaft hole 4b1 through which the rotation shaft portion 3a is inserted at the center, and a top surface portion of the upper holding portion 4a, The rotating portion 3b can be press-fitted from the upper side, and the arm holding portion 4c that holds the press-fitted rotating portion 3b, and the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion from the end portion of the frame 2. The frame insertion portion 2 which is a part of the frame 2 toward which the frame insertion portion 2 is thinner than the shortest distance a between the upper end portion of the bearing recess 4b2 and the upper holding portion 4a.
A method of assembling a liquid level sensor including a and
The arm holder 4 is attached to the frame 2 so that the inner side of the detour 4d faces the upper bearing cylinder 2a2.
A step of sandwiching the frame 2 with the arm holder 4 while inclining the frame 2 at a predetermined angle with respect to, and abutting and abutting the inner portion of the bypass portion 4d with the upper bearing tubular portion 2a2.
A fitting step of lifting the arm holder 4 with respect to the frame 2 and fitting the lower bearing cylindrical portion 2a3 into the bearing recess 4b2, and the rotating shaft portion 3a to the frame portion rotating shaft hole 2a1 and the holder portion. The insertion step of inserting the rotary shaft hole 4b1 and the rotation portion 3b into the arm holding portion 4
and a press-fitting step of press-fitting into c.

According to the fifth aspect of the invention, the bypass portion 4d is brought into contact with the upper bearing tubular portion 2a2 in the sandwiching contact step,
By the fitting process, the lower bearing cylindrical portion 2a3 becomes the bearing concave portion 4b2.
Is fitted to. Further, the float arm 3 is inserted into each shaft hole in the inserting step, and the float arm 3 is press-fitted into the arm holding portion 4c in the press-fitting step. By such an assembling method, the lower holding portion 4b of the float arm 3 having a U-shaped cross section
The liquid level sensor provided with the bearing recessed portion 4b2 used to maintain the rotational stability, which is provided so as to project from the upper surface portion to the bypass portion 4d, can be easily assembled.
As a result, the lower bearing cylindrical portion 2a through which the float 6 is inserted
By fitting 3 into the bearing recess 4b2, it is possible to obtain a liquid level sensor in which the rotational stability of the float arm 3 is maintained and the number of parts does not increase. That is, a liquid level sensor having high detection accuracy can be obtained without inviting cost increase and strength reduction. Further, the degree of freedom of the swinging direction of the float arm 3, that is, the rotation range is widened, and a liquid level sensor that can be attached to various places can be obtained.

According to a sixth aspect of the present invention, there is provided a liquid level sensor assembling method as set forth in the fifth aspect, wherein the liquid level sensor is assembled as shown in FIGS. 3 and 4. The arm holder 4 may further include a rotating step of rotating the arm holder 4 so as to be parallel to the longitudinal direction of the frame 2.

According to the invention of claim 6, the frame 2
Assembling the arm holder 4 to the frame 2 becomes easier by further including a rotating step of rotating so as to be parallel to the longitudinal direction of the arm holder 4.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, the structure and operation of the liquid level sensor of the present invention will be described with reference to FIGS. 1 and 2. FIGS. 1A and 1B are a plan view and an enlarged cross-sectional view of an essential part showing an embodiment of a liquid level sensor according to the present invention, respectively. 2A and 2B are respectively shown in FIG.
3 is a perspective view of the liquid level sensor shown in FIG. 2 and an exploded perspective view showing a state in which a frame and an arm holder are separated.

As shown in FIGS. 1 (A) and 1 (B), the liquid level sensor 1 of the present embodiment includes a resin frame 2,
A float arm 3 made of metal, an arm holder 4 made of resin, and a float 6 having buoyancy with respect to the liquid to be measured are included.

As shown in FIGS. 1 (A) and 1 (B), in the present liquid surface level sensor 1, a float that moves up and down as indicated by an arrow in the drawing in accordance with the fluctuation of the liquid surface level of the liquid to be measured. The float arm 3 to which 6 is attached rotates within a predetermined rotation angle range. The frame 2 is an electric circuit for detecting the liquid level, for example, a Hall element 5c described later.
Etc. Its outer shape is seen from above, as shown in FIG.
As shown in, the shape is close to a rectangle. The frame 2 is formed with an electronic device housing portion 2b that is open to the upper side. In the electronic device housing portion 2b, there are a hall element 5c as a magnetoelectric conversion element that detects a magnetic force from a ring-shaped magnet 5a described later and converts the magnetic force into an electric signal, and a wiring board 5d on which the hall element 5c and the like are mounted. It is housed. The wiring board 5d is connected to an output terminal 5e for guiding the electric signal output from the Hall element 5c to the outside. The electronic device housing portion 2b is filled with a molding material (not shown). This electrical signal will be described later,
This corresponds to the rotatable angle of the float arm 3, that is, the liquid level. A core 5f as a magnetism collecting member is also attached to the frame 2.

On the upper surface of the frame 2, a cylindrical upper bearing cylindrical portion 2a2 having a frame portion rotary shaft hole 2a1 through which the rotary shaft portion 3a is inserted at the center is provided in a protruding manner. Further, on the lower surface of the frame 2, a lower bearing cylindrical portion 2a3 is formed which is hollowed out in an annular shape to have a cylindrical shape, and has a frame portion rotation shaft hole 2a1 at the center. A part of the frame 2 extending from the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion toward the end of the frame 2 is formed with a frame insertion portion 2a having a thickness b smaller than other portions of the frame 2. The thickness b of the frame insertion portion 2a is determined by the bearing recess 4b.
It is formed so as to be thinner than the shortest distance a between the upper end of 2 and the upper holding portion 4a. The rotary shaft hole 2
The diameter of a1 is gradually reduced as it goes downward from the opening.

The float arm 3 is in the shape of a single metal rod, and is a fulcrum of rotation. The rotary shaft portion 3a and the rotary shaft portion 3a are bent at a substantially right angle to rotate about the rotary shaft portion 3a. It is composed of a rotating portion 3b. A cylindrical float 6 made of a material having buoyancy with respect to the liquid to be measured is attached to the tip of the rotating portion 3b of the float arm 3. The tip of the rotating portion 3b is fixed by penetrating the center of both bottom surfaces of the float 6.

The arm holder 4 holds the float arm 3 and meshes with the frame 2 to rotate the held float arm 3 within a predetermined rotation angle range with the rotation shaft portion 3a as a fulcrum. Let As shown in FIG. 1 (B), the arm holder 4 has a U-shaped cross section including an upper holding portion 4a and a lower holding portion 4b which are formed so as to sandwich the frame 2 from above and below and to be substantially parallel to each other. Are doing Further, as shown in FIGS. 1A and 2B, the arm holder 4 is a part of the upper holding portion 4a, and is detoured so as not to hinder the rotation of the float arm 3. It has a bypass portion 4d. The inner portion of the detour 4d has a semicircular shape, but in detail, it has a shape like a heart shape halved. This detour 4d is
As will be described with reference to FIG. 3, one end 4d1 of the bypass portion 4d connected to the straight portion is formed so that the upper bearing tubular portion 2a2 can be easily assembled.
Has a slightly open shape than the semicircle.

As shown in FIGS. 1 (B) and 2 (B),
A bearing recess 4b2 is provided on the upper surface of the lower holding portion 4b of the arm holder 4 so as to project toward the detour portion 4d. The bearing recess 4b2 is formed in the lower bearing cylindrical portion 2a of the frame 2.
3 has a cylindrical inner wall corresponding to 3 and further has a rotating shaft portion 3a.
It has a holder part rotation shaft hole 4b1 through which the is inserted in the center part. A magnet 5a is attached to the outer wall of the bearing recess 4b2. The lower bearing cylindrical portion 2a3 is rotatably fitted in the bearing recess 4b2.

The rotating portion 3b of the float arm 3 can be press-fitted into the upper surface of the upper holding portion 4a of the arm holder 4 from above, and the upper side holding the pressed rotating portion 3b is opened. An arm holding portion 4c having a claw shape is formed.

The frame 2 and the arm holder 4 are separately molded as shown in FIG. 2 (B). Then, the lower bearing cylindrical portion 2a3 and the bearing recess 4b2
, The rotary shaft portion 3a is inserted through the frame rotary shaft hole 2a1 and the holder rotary shaft hole 4b1, and the arm holding portion 4c holds the rotary portion 3b. Assembled as shown in A). The assembling method thereof will be described later with reference to FIGS. 3 and 4.

The liquid level sensor 1 having such a structure is
It is attached to a container (not shown) that stores a liquid to be measured such as gasoline. Then, when the float 6 moves up and down due to the fluctuation of the liquid level, the float arm 3 moves to the rotating shaft portion 3.
It rotates within a predetermined angle range θ1 with a as a fulcrum. The magnet 5 detected by the Hall element 5c by this rotation
The magnetic force from a changes, and an electric signal indicating the liquid level based on this change can be taken out from the output terminal 5e.

In the above embodiment, the upper bearing tubular portion 2a2
The lower bearing cylindrical portion 2a3 is provided at a position (left side in the drawing) deviated from the center of the frame 2, so that the float arm 3 rotates on the opposite side (right side in the drawing). Attached to. This allows the float arm 3
Can rotate above the frame 2, and the liquid level sensor including the rotation range of the float arm 3 can be downsized. As a result, the liquid level sensor can be attached to a small tank, and thus the degree of freedom in the place of attachment is increased.

Next, a method of assembling the above-mentioned liquid level sensor 1 will be described with reference to FIGS. 3 and 4.
3 (A) and (B), and FIG. 4 (A) and (B)
FIG. 4 is an explanatory diagram showing a method of assembling the liquid level sensor 1. Assembling order is shown in FIG. 3 (A), FIG. 3 (B), and FIG.
(A), proceed in the order of FIG. 4 (B), and in each drawing,
The upper drawing is based on a plan view and the lower drawing is based on a sectional view.

First, as shown in FIG. 3 (A), the arm holder 4 is mounted on the frame 2 so that the inner side of the detour 4d of the arm holder 4 faces the upper bearing cylinder 2a2 of the frame 2. Tilt at a specified angle. At this time, the straight part of the open end 4d1 of the bypass 4d having the above-described inner shape is arranged so as to be parallel to the longitudinal direction of the frame 2. By arranging in this way, the bypass portion 4d of the arm holder 4 can be separated from the upper bearing tubular portion 2
It becomes easy to assemble to a2. That is, it is only necessary to translate the arm holder 4 toward the frame 2 in the direction indicated by the arrow in the figure. Then, in the figure, the arm holder 4 is moved in the direction indicated by the arrow to move the frame 2 to the arm holder 4
And the inner side portion of the bypass 4d is brought into contact with the upper bearing tubular portion 2a2. The step shown in FIG. 3A corresponds to the pinching contact step of claim 5.

Next, as shown in FIG. 3B, the arm holder 4 is lifted with respect to the frame 2 in the direction indicated by the arrow to fit the lower bearing cylindrical portion 2a3 into the bearing recess 4b2. The step shown in FIG. 3B corresponds to the fitting step of claim 5.

Next, as shown in FIG. 4 (A), the arm holder 4 is rotated in the direction indicated by the arrow so as to be parallel to the longitudinal direction of the frame 2. The step shown in FIG. 4A corresponds to the rotating step of claim 6.

Finally, as shown in FIG. 4B, the rotary shaft portion 3a of the float arm 3 is connected to the frame portion rotary shaft hole 2a1.
Then, the holder portion rotation shaft hole 4b1 is inserted, and the rotating portion 3b is press-fitted into the arm holding portion 4c, whereby a series of assembling is completed.

With such an assembling method, the float arm 3 is used to maintain the rotational stability of the U-shaped float arm 3 projecting from the upper surface of the lower holding part 4b toward the detour part 4d. The liquid level sensor provided with the bearing recess 4b2 can also be easily assembled. Note that reference numerals given in FIGS. 3 and 4 are the same as those shown in FIGS. 1 and 2, and thus duplicated description thereof will be omitted.

As described above, according to this embodiment, in order to maintain the rotational stability, the bearing recess 4b is formed on the inner surface.
The U-shaped float arm 3 having the U-shaped cross section can be easily assembled to the frame 2. As a result, the lower bearing cylindrical portion 2 through which the float arm 3 is inserted
The float arm 3 is formed by fitting the a3 and the bearing recess 4b2.
It is possible to obtain a liquid level sensor that keeps the rotational stability of No. 1 and does not increase the number of parts. That is, a liquid level sensor having high detection accuracy can be obtained without inviting cost increase and strength reduction. Further, the degree of freedom of the swinging direction of the float arm 3, that is, the rotation range is widened, and a liquid level sensor that can be attached to various places can be obtained.

[0049]

As described above, according to the first aspect of the invention, the rotation stability of the float arm 3 is stabilized by fitting the lower bearing cylindrical portion 2a3 into which the float arm 3 is inserted and the bearing recess 4b2. It is possible to obtain a liquid level sensor that maintains the property and does not increase the number of parts. That is, a liquid level sensor having high detection accuracy can be obtained without inviting cost increase and strength reduction. In addition, the degree of freedom of the swinging direction of the float arm 3, that is, the range of rotation is widened
It is possible to obtain a liquid level sensor that can be attached to various places.

According to the second aspect of the present invention, the upper bearing cylindrical portion 2a2 and the lower bearing cylindrical portion 2a3 are provided at positions deviated from the center of the frame 2, and the float arm 3 is different from this. It is mounted so that it rotates on the opposite side. As a result, the float arm 3 can rotate above the frame 2, and the liquid level sensor including the rotation range of the float arm 3 can be downsized. As a result, the degree of freedom of the mounting place is increased.

According to the third aspect of the present invention, since the upper bearing tubular portion 2a2 is cylindrical and the inner wall of the bypass portion 4d is semicircular, the assembly can be smoothly performed. Also,
It is easy to manufacture these parts.

According to the fourth aspect of the present invention, the one end 4d1 which is in contact with the straight line portion has a semicircular shape which is half of a heart shape which is larger than the other end. Therefore, this open portion is used. Then, the upper bearing tubular portion 2a2 of the frame 2 is easily assembled.

According to the fifth aspect of the present invention, the upper surface of the lower holding portion 4b of the U-shaped float arm 3 in cross section is formed by the assembling method including the sandwiching contacting step, the fitting step, the inserting step, and the press-fitting step. It is possible to easily assemble the liquid level sensor provided with the bearing recess 4b2 that is used to maintain the rotational stability and that is provided so as to project from the portion toward the bypass 4d. As a result, the lower bearing cylindrical portion 2a3 through which the float 6 is inserted is fitted into the bearing recess 4b2 to maintain the rotational stability of the float arm 3 and to obtain a liquid level sensor without increasing the number of parts. To be That is, a liquid level sensor having high detection accuracy can be obtained without inviting cost increase and strength reduction. Further, the degree of freedom of the swinging direction of the float arm 3, that is, the rotation range is widened, and a liquid level sensor that can be attached to various places can be obtained.

According to the invention described in claim 6, the frame 2
Assembling the arm holder 4 to the frame 2 becomes easier by further including a rotating step of rotating so as to be parallel to the longitudinal direction of the arm holder 4. As a result, the assembly time of the liquid level sensor is shortened.

[Brief description of drawings]

1A and 1B are a plan view and an enlarged sectional view of an essential part showing an embodiment of a liquid level sensor according to the present invention, respectively.

2A and 2B are a perspective view of the liquid level sensor shown in FIG. 1 and an exploded perspective view showing a state in which a frame and an arm holder are separated, respectively.

3A and 3B show a liquid level sensor 1.
It is explanatory drawing which shows the assembling method of.

4A and 4B are explanatory views showing an assembling method subsequent to FIG.

FIG. 5A is a plan view showing an example of a conventional liquid level sensor of this type. FIG. 5B is an enlarged cross-sectional view of a main part of the liquid level sensor shown in FIG.

FIG. 6A is a plan view showing another example of a conventional liquid level sensor. FIG. 6B is an enlarged cross-sectional view of a main part of the liquid level sensor shown in FIG.

FIG. 7A is an explanatory diagram showing a state before the arm holder is divided. FIG. 7B is an explanatory view showing a state where the arm holder is divided.

[Explanation of symbols]

1 Liquid level sensor 2 frames 2a Frame insertion part 2a1 Frame part rotation shaft hole 2a2 Upper bearing cylinder 2a3 Lower bearing cylindrical part 3 float arms 3a rotating shaft 3b Rotating part 4 arm holder 4a Upper holding part 4b Lower holding part 4b2 bearing recess 4c Arm holding part 4d detour 6 floats

Claims (6)

[Claims] 1. A rod-shaped float arm formed by a rotary shaft portion and a rotary portion that is bent substantially at right angles to the rotary shaft portion and that rotates about the rotary shaft portion, and the rotation of the float arm. Attached to the tip of the part,
A float having buoyancy with respect to the liquid to be measured, a frame on which an electric circuit for detecting the liquid level of the liquid to be measured based on the rotation of the float arm is mounted, and a frame protruding from the upper surface of the frame. A cylindrical upper bearing cylinder portion having a frame portion rotation shaft hole through which the rotation shaft portion is inserted, and a lower surface portion of the frame, which is formed into a hollow cylindrical shape, A lower bearing cylindrical portion having a shaft hole at the center, and an arm holder having a U-shaped cross section including an upper holding portion and a lower holding portion formed so as to be substantially parallel to each other with the frame sandwiched from above and below. A part of the upper holding part, which is formed so as to bypass the rotation of the float arm, and a projecting part from the upper surface part of the lower holding part toward the detour part. The lower shaft A bearing concave portion having a cylindrical inner wall corresponding to the cylindrical portion and having a holder portion rotation shaft hole through which the rotation shaft portion is inserted in the center portion, and the rotation formed on the upper surface portion of the upper holding portion. A portion is press-fittable from the upper side, and is an arm holding portion that holds the press-fitted rotating portion, and a part of the frame that extends from the upper bearing cylindrical portion and the lower bearing cylindrical portion toward the end of the frame, A frame insertion part that is thinner than the shortest distance between the upper end part of the bearing recess and the upper holding part, the lower bearing cylindrical part and the bearing recess are fitted, and the rotary shaft part rotates the frame part. A liquid level sensor, wherein the arm holding part holds the turning part through the shaft hole and the holder part rotation shaft hole. 2. The liquid level sensor according to claim 1, wherein the upper bearing cylindrical portion and the lower bearing cylindrical portion are provided at positions deviated from a central portion of the frame, and the float arm includes: Where the float is provided with the upper bearing cylindrical portion and the lower bearing cylindrical portion,
A liquid level sensor, wherein the liquid level sensor is mounted so as to rotate on the opposite side of the center portion. 3. The liquid level sensor according to claim 2, wherein the upper bearing tubular portion has a cylindrical shape, and the inner portion of the bypass portion has a semicircular shape. . 4. The liquid level sensor according to claim 3, wherein the inner portion of the bypass portion has a semicircular shape in which one end that is in contact with the straight line portion is wider than the other end, and is a half heart shape. Is a liquid level sensor. 5. A rod-shaped float arm formed by a rotating shaft portion and a rotating portion that is bent substantially at right angles to the rotating shaft portion and rotates about the rotating shaft portion, and rotation of the float arm. Attached to the tip of the part,
A float having buoyancy with respect to the liquid to be measured, a frame on which an electric circuit for detecting the liquid level of the liquid to be measured based on the rotation of the float arm is mounted, and a frame protruding from the upper surface of the frame. A cylindrical upper bearing cylinder portion having a frame portion rotation shaft hole through which the rotation shaft portion is inserted, and a lower surface portion of the frame, which is formed into a hollow cylindrical shape, A lower bearing cylindrical portion having a shaft hole at the center, and an arm holder having a U-shaped cross section including an upper holding portion and a lower holding portion formed so as to be substantially parallel to each other with the frame sandwiched from above and below. A part of the upper holding part, which is formed so as to bypass the rotation of the float arm, and a projecting part from the upper surface part of the lower holding part toward the detour part. The lower shaft A bearing concave portion having a cylindrical inner wall corresponding to the cylindrical portion and having a holder portion rotation shaft hole through which the rotation shaft portion is inserted in the center portion, and the rotation formed on the upper surface portion of the upper holding portion. A portion is press-fittable from the upper side, and is an arm holding portion that holds the press-fitted rotating portion, and a part of the frame that extends from the upper bearing cylindrical portion and the lower bearing cylindrical portion toward the end of the frame, A method for assembling a liquid level sensor, comprising: a frame insertion part that is thinner than the shortest distance between the upper end of the bearing recess and an upper holding part, wherein an inner part of the bypass part faces the upper bearing cylinder part. So that the arm holder is tilted at a predetermined angle with respect to the frame, the frame is sandwiched by the arm holder, and a sandwiching contact step of contacting an inner portion of the bypass portion with the upper bearing cylinder portion, The above Lift the Muhoruda relative to the frame,
A fitting step of fitting the lower bearing cylindrical portion into a bearing recess, an inserting step of inserting the rotary shaft portion through the frame rotary shaft hole and the holder rotary shaft hole, and the rotating portion through the arm A method of assembling a liquid level sensor, comprising: a press-fitting step of press-fitting into a holding portion. 6. The liquid level sensor according to claim 5, further comprising a step of rotating the arm holder so as to be parallel to a longitudinal direction of the frame. How to assemble.