JP2000162022A - Liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liq. level detector having a fixing structure of a float arm easy to assemble with the number of components restricted. SOLUTION: The liquid level detector comprises a float arm 2 having a float floating on the lid. surface, an arm holder 4 which holes the float arm 2 and moves with the rotation of the float arm 2, a slide board 5 having a slide contact fixed to the arm holder 4, and a main frame 3 having a circuit board 7 in contact with the slide contact. The frame 3 has a bearing 21 having a through-hole 20, the arm holder 4 has a shaft 25 to be inserted in the bearing 21, the shaft 25 has an elastically deformable lock piece 26 having a lock claw 27, the shaft 25 has a hole 33 for inserting the float arm 2, the shaft 25 is inserted in the through-hole 20 and secured to an opening 31 of the bearing 21 through the lock claw 27, and a base end shaft 12 of the float arm 2 is inserted in the hole 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detecting device, and more particularly to a liquid level detecting device having a floating arm bearing structure.

[0002]

2. Description of the Related Art A conventional liquid level detecting device 1 is disclosed in
As shown in FIG. 10 and FIG. 11, a float arm 2 provided with a float (not shown) that moves due to a change in the liquid level and provided at the tip is rotatably supported on the main body frame 3.

The float arm 2 is provided with an arm holder 4 which moves with the rotation of the float arm 2.

A sliding plate 5 is fixed to the arm holder 4,
A sliding contact 6 protrudes from the tip of the sliding plate 5. A pair of opposing pieces 4a are formed on the upper part of the arm holder 4,
The opposing surface of the opposing piece 4a is formed in an arc shape so as to conform to the outer surface shape of the float arm 2, and the float arm 2 is pressed into the arc surface while pushing the opposing piece 4a from the upper open portion between the opposing pieces 4a. The float arm 2 is configured so as not to come out upward due to the elastic restoring force of the facing piece 4a. The positional relationship between the float arm 2 and the sliding plate 5 is determined via the arm holder 4.

The sliding contact 6 is configured to slide on a circuit board 7 made of ceramic provided on the main body frame 3 with a predetermined contact pressure.

The circuit board 7 has a band-shaped resistor (not shown) on its surface and a band-shaped comb-shaped electrode (not shown) along the band-shaped resistor. The sliding contact 6 is slid to ground by pressure.
And outputting a current change corresponding to a variable resistance amount with respect to a base end of the resistor to detect a liquid amount.

The conventional bearing structure of the float arm 2 in the liquid level detecting device 1 has a bearing fitting portion 8 formed at a position corresponding to the main body frame 3, and a bearing member 9 is mounted on the bearing fitting portion 8. The arm member 4 and the sliding plate 5 are fitted on the bearing member 9 so as to be rotatable, and the shaft hole 10 provided on the bearing member 9 and the shaft hole 11 provided on the base of the arm holder 4 are provided. A base shaft 12 obtained by bending the float arm 2 in an L-shape in a substantially right angle direction is inserted therethrough.
A push nut as a slip-off preventing member 13 is press-fitted into a tip end portion 12a that protrudes from the lower surface of the bearing member 9 and the float arm 2 is pulled down by the press-fitting of the push nut 13 and crimped.

Further, a flange-shaped flange portion 14 is formed on the outer periphery of the base shaft 12 of the float arm 2 on the way of the base shaft 12 by header processing to form a flange-shaped flange portion 14.
5 is formed around the shaft hole 11 of the arm holder 4, and a contact surface 16 is formed at a position where it contacts the bearing member 9. At this time, the arm holder 4 provided with the sliding plate 5 receives the flange 14 of the float arm 2 on the receiving surface 15 and the float arm 2
The arm holder 4 and the sliding plate 5 are assembled so as not to rattle.

Therefore, when the push nut 13 is tightened, the base shaft 12 of the float arm 2 is pulled downward, and the flange 14 of the float arm 2 receives the receiving surface 15.
The contact surface 16 of the arm holder 4 contacts the bearing member 9.
The bearing member 9 is fixed while being sandwiched between the arm holder 4 and the push nut 13, so that the float arm 2 and the bearing member 9 rotate together. A force is always applied to the upper side of the arm holder 4 by a coil spring 17 electrically connected to the sliding plate 5. The upward force of the coil spring 17 is applied to the stepped portion 8a of the bearing fitting portion 8.
Arm 2 which is received by the step portion 9a of the bearing member 9
Together with the bearing member 9 are prevented from falling upward. Since the bearing member 9 protrudes from the main body frame 3 and abuts on the arm holder 4 and the main body frame 3 is separated from the arm holder 4, the assembly of the float arm 2, the arm holder 4 and the bearing member 9 becomes the main body. It rotates with respect to the frame 3.

Reference numerals 18 and 19 denote terminals. One terminal 18 is connected to the circuit board 7 and the other terminal 19 is connected to the slide plate 5 via a coil spring 17.

[0011]

In recent years, there has been a demand for reducing the manufacturing cost of the liquid level detecting device, and it has been desired to reduce the manufacturing cost of the liquid level detecting device. SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid level detecting device having a float arm fixing structure that can reduce the number of parts and is easy to assemble.

[0012]

The present invention comprises a float arm having a float floating on a liquid surface, an arm holder holding the float arm and moving with the rotation of the float arm, and a sliding contact. In a liquid level detection device including a sliding plate fixed to the arm holder and a main body frame including a circuit board with which the sliding contact contacts, a bearing portion having a through hole in the main body frame is provided. A shaft portion to be inserted into the bearing portion is provided on the arm holder, a locking piece elastically deformable is provided on the shaft portion, a locking claw is provided on the locking piece, and the float arm is inserted into the shaft portion. A hole is provided, the shaft portion is inserted into the through hole, the locking claw is locked in the opening of the bearing portion, and the float arm is inserted into the hole.

[0013] Further, a stepped portion facing the surface of the locking claw that comes into contact with the opening of the bearing portion is provided on the shaft portion.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid level detecting device according to the present invention comprises: a float arm 2 having a float floating on a liquid surface; an arm holder 4 holding the float arm 2 and moving as the float arm 2 rotates. A sliding plate 5 having sliding contacts 6 and fixed to the arm holder 4 and a circuit board 7 with which the sliding contacts 6 come into contact
And a main body frame 3 having
A bearing 21 having a through hole 20 is provided in the bearing 2.
1 is provided on the arm holder 4 and the shaft 2
5 is provided with an elastically deformable locking piece 26, a locking claw 27 is provided on the locking piece 26, a hole 33 is provided in the shaft 25 for the float arm 2 to be inserted, and the shaft 25 is inserted into the through hole 20. Then, the base 31 of the float arm 2 is inserted into the hole 33 by locking the opening 31 of the bearing portion 21 with the locking claw 27, so that the number of parts is reduced, and the arm holder 4 and the float The arm 2 can be assembled from one direction, the assembling is easy, and the productivity can be improved while suppressing the manufacturing cost.

The opening 3 of the bearing 21 of the locking claw 27
By providing the step portion 30 facing the surface 32 that contacts the shaft 1 in the shaft portion 25, the axial displacement of the shaft portion 25 can be suppressed, and reliable contact between the sliding contact 6 and the circuit board 7 can be ensured. Obtainable.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment of the present invention. The same and corresponding parts as in the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted.

The liquid level detecting device 1 of the present invention has a float (not shown) at the tip of the float arm 2 which floats on the liquid level. The arm holder 4 moves with the rotation of the float arm 2. The main body frame 3 is provided with a bearing 21 having a through hole 20. The through hole 20 has a large diameter portion 22 and a small diameter portion 23. As shown in FIG. 5, the large diameter portion 22 is located on the upper side in the figure, and the large diameter portion 22 and the small diameter portion 2 are located.
A step 24 is provided at the boundary with 3. In addition, large diameter part 2
2. The inner surfaces of the small diameter portions 23 are all cylindrical.

The arm holder 4 is provided with a shaft 25 to be inserted into the bearing 21. An elastically deformable locking piece 26 is provided on the distal end side of the shaft portion 25. The two locking pieces 26 are provided.
Is provided with a locking claw 27 at its end. The shaft portion 25 also has a large-diameter portion 28 and a small-diameter portion 29, and the portion of the locking piece 26 is a small-diameter portion 29. As shown in FIG. It is. And the small diameter part 29 and the large diameter part 28
A step 30 is provided at the boundary between the two. The cross section of the large diameter portion 28 and the small diameter portion 29 of the shaft portion 25 is similar to an ellipse formed by connecting a semicircle and a semicircle with a straight line. It is formed to be large.

The small-diameter portion 23 of the bearing portion 21 corresponds to the small-diameter portion 29 of the shaft portion 25, and the large-diameter portion 22 of the bearing portion 21 corresponds to the shaft portion 25.
And the large diameter portion 28 of FIG. Shaft 25
The small diameter portion 29 and a part of the outer surface of the large diameter portion 28
Abuts on the cylindrical inner surface of the through hole 20 and smoothly rotates.

In particular, the large-diameter portion 28 allows the arm holder 4 to rotate more smoothly than the small-diameter portion 29 provided with the elastically deformable locking piece 26.

The locking claw 27 has a surface 32 which comes into contact with the opening 31 of the bearing portion 21.
And the step portion 30 of the shaft portion 25, the small-diameter portion 23 of the through hole 20 is formed.
Respectively, and abuts the opening 31 and the step 24, and restricts the arm holder 4 from moving in the axial direction of the proximal shaft 12. The arm holder 4 does not come off the main body frame 3 by coming into contact with the opening 32 of the through hole 20 by the surface 32 of the locking claw 27.

A through hole 33 is formed in the shaft portion 25 of the arm holder 4. The hole 33 is connected to the locking piece 26, and the portion of the locking piece 26 connected to the hole 33 has a curved inner surface. The base shaft 12 of the float arm 2 is inserted into the hole 33. When the base shaft 12 is inserted into the hole 33, the elastically deformable locking piece 26 cannot be deformed, and the arm holder 4 does not come off the main body frame 3 unless the base shaft 12 is pulled out from the hole 33.

In this embodiment, the sliding plate 5 is held by an elastic piece 35 having a locking claw 34 provided on the arm holder 4 while the shaft 25 of the arm holder 4 penetrates.

Next, a method of assembling the float arm 2 according to the present invention will be described. First, the arm holder 4 having only the sliding plate 5 is attached to the main body frame 3. The shaft portion 25 is inserted into the through hole 20 from above in FIG. The locking piece 26 is deformed when the locking claw 27 abuts on the inner surface of the small diameter portion 23, and when the locking claw 27 passes through the through hole 20, the stepped portion 30 of the shaft portion 25 is
Abuts on the step 24 of the through hole 20, the deformed locking piece 26 is restored, the surface 32 of the locking claw 27 is locked in the opening 31 of the through hole 20, and the arm holder 4 is Not get out of

Next, the base shaft 12 of the float arm 2
Is inserted into the hole 33 of the arm holder 4 from above in FIG. Then, the float holder 2 is fixed to the arm holder 4 by press-fitting the arm holder 4 between the opposing pieces 4a. By inserting the base shaft 12 into the hole 33, the locking piece 26 cannot be deformed.
The arm holder 4 is not detached from the main body frame 3 unless the float arm 2 is detached.

In this embodiment, the base shaft 12 has the hole 33.
And the distal end portion 12a is exposed outside the distal end portion of the locking piece 26, but if the deformation of the locking piece 26 is to be prevented, the base shaft 12 is No need to expose.

With the above configuration, the float arm 2 can be rotatably fixed without using the bearing member 9 and the slip-off preventing member 13 as in the conventional example, so that the number of parts can be reduced and the parts can be assembled. However, instead of assembling the components from the upper and lower two directions of the main body frame 3 such as the float arm 2 from the upper side and the detachment preventing member 13 from the lower side as in the conventional example, the upper side 1 of the main body frame 3 is not mounted.
Since assembly from the direction is sufficient, workability is improved, and production costs can be reduced.

Note that L1 and L2 are lead wires, and both the lead wires L1 and L2 are connected to the circuit board 7, and are connected to each other via the circuit board 7, the sliding contacts 6, and the sliding plate 5.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same and corresponding parts as those in the conventional example and the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the upper part of the arm holder 4
Two locking claws 4b and two receiving portions 36 are formed for positioning and fixing the float arm 2 to the arm holder 4, and the locking claws 4b and the receiving portion 36 are formed in the outer surface shape of the float arm 2. The arcuate surface is formed so as to match, the base shaft 12 of the float arm 2 penetrates the hole 33 of the arm holder 4, and the float arm 2 is rotated rightward from the position of the dashed line in FIG. The float arm 2 is press-fitted into the circular arc surface while pushing and expanding the locking claw 4b from the side opening portion of the receiving portion 4b and the receiving portion 36, and the float claw 4b does not come out sideways due to the elastic restoring force of the locking claw 4b. It is configured to be stopped. Further, a mortar-shaped guiding portion 37 is formed near the hole 33 of the arm holder 4, and the float arm 2 is assembled so as to be supported by the receiving portion 36 of the arm holder 4.

In the first embodiment, a flange-shaped flange portion 14 is formed on the outer periphery of the base shaft 12 of the float arm 2 by header processing to form a flange-shaped flange portion 14, and this flange portion 14 is attached to the receiving surface 15 of the arm holder 4. To determine the position of the float arm 2 and the arm holder 4 in the axial direction of the base shaft 12 of the float arm 2 and the float arm 2 and the arm holder 4.
In this embodiment, the float arm 2 is received by the locking claw 4b of the arm holder 2 and the receiving portion 36, and the float arm 2 is connected to the arm holder 4. Since the position of the base shaft 12 in the axial direction can be determined to prevent the float arm 2 from rattling with the arm holder 4 and the sliding plate 5, the base shaft of the float arm 2 as in the first embodiment can be prevented. It is not necessary to form the collar portion 14 on 12, and the processing cost of the float arm 2 can be reduced. In addition, since there is no flange 14, the liquid level detecting device 1 can be made thinner accordingly.

[0032]

As described above, according to the present invention, there is provided a liquid level detecting apparatus which can achieve the initial object, has a small number of parts, is easy to assemble, and can improve the productivity. be able to.

[Brief description of the drawings]

FIG. 1 is a top view of a first embodiment of the present invention.

FIG. 2 is a bottom view of the embodiment.

FIG. 3 is a sectional view taken along line AA in FIG. 1 of the embodiment.

FIG. 4 is a sectional view taken along line BB in FIG. 1 of the embodiment.

FIG. 5 is a cross-sectional view for explaining the assembling of line AA in FIG. 1 of the embodiment.

FIG. 6 is a top view of a second embodiment of the present invention.

FIG. 7 is a sectional view of the same example taken along line CC in FIG. 6;

FIG. 8 is a sectional view of the same example taken along line DD in FIG. 6;

FIG. 9 is an explanatory view of assembling the float arm of the embodiment.

FIG. 10 is a top view of a conventional example.

FIG. 11 is a sectional view of the conventional example taken along line EE in FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid-level detection apparatus 2 Float arm 3 Main frame 4 Arm holder 4a Opposing piece 5 Sliding plate 6 Sliding contact 7 Circuit board 8 Bearing fitting part 8a Step part 9 Bearing member 9a Step part 10 Shaft hole 11 Shaft hole 12 base End shaft 12a Tip portion 13 Pull-out preventing member (push nut) 14 Collar portion 15 Receiving surface 16 Contact surface 17 Coil spring 18, 19 Terminal 20 Through hole 21 Bearing portion 22 Large diameter portion 23 Small diameter portion 24 Step 25 Shaft portion 26 Stop piece 27 Locking claw 28 Large diameter portion 29 Small diameter portion 30 Stepped portion 31 Opening 32 Surface 33 Hole 34 Locking claw 35 Elastic piece 36 Receiving portion 37 Inviting portion

Claims (2)

[Claims] 1. A float arm having a float floating on a liquid surface, an arm holder holding the float arm and moving with the rotation of the float arm, and a slide fixed to the arm holder having a sliding contact. In a liquid level detecting device comprising a moving plate and a main body frame provided with a circuit board with which the sliding contact comes into contact, a shaft portion provided with a through hole in the main body frame and inserted into the bearing portion Is provided on the arm holder, an elastically deformable locking piece is provided on the shaft, a locking claw is provided on the locking piece, a hole is provided in the shaft for the float arm to be inserted, and the shaft is A liquid level detecting device, wherein the liquid level detecting device is inserted into the through hole, is locked to the opening of the bearing portion by the locking claw, and the float arm is inserted into the hole. 2. The liquid level detecting device according to claim 1, wherein a step portion is provided on the shaft portion, the step portion being opposed to a surface of the locking claw that comes into contact with the opening of the bearing portion.