JPH03124954A - Liquid level detecting device - Google Patents

Abstract

PURPOSE:To improve the precision of the detected value of a liquid level detecting means by arranging a fixing means for fixing the housing of the liquid level detecting means in close contact with the bottom wall section in a tank. CONSTITUTION:A fixing means (sub-tank) 6 is arranged in close contact with the bottom wall section in a tank 2, and the housing of a liquid level detecting means 5 fixed on the fixing means 6 is invariably located at the constant height from the bottom wall section of the tank 2. Even if the tank 2 is expanded by the fluctuation of the internal pressure of the tank 2, the height of the housing of the detecting means 5 is kept constant from the bottom wall section of the tank 2, thus the liquid level of a liquid is precisely detected by a float 51 fitted at the tip of a float arm 52.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a liquid level detection device.

[Prior Art] Conventionally, in Japanese Patent Application Laid-Open No. 1-159456,
A fuel sender incorporated into a vehicle fuel supply system is disclosed. This type of fuel sender includes a float floating on the fuel liquid m1, a float arm attached to the tip of the float, and a housing that rotatably supports the float arm. The housing was suspended from a cover that closed an opening formed in the earthen wall of the fuel tank.

[Problems to be Solved by the Invention] However, the internal pressure of the fuel tank fluctuates, for example, by about 0 to 0.15 kf/aA depending on temperature changes and fuel properties.

Due to such fluctuations in the internal pressure within the fuel tank, there is a possibility that the height of the fuel tank may change by, for example, ±5 degrees.

If a mounting method such as the above-mentioned fuel sender is used, when the fuel tank expands, the float will rise to a certain height even at the E (empty) point when there is little fuel left, so the vehicle occupants There was a possibility that the fuel could be mistakenly recognized as having a large amount of fuel remaining. Furthermore, since the height of the float decreases when the fuel tank is compressed, there is a possibility that the vehicle occupant may mistakenly believe that the remaining amount of fuel is low.

Therefore, in the mounting method in which the fuel sender is suspended from the upper wall of the fuel tank, there is a possibility that an error may occur in the detected value of the fuel level by the fuel sender.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid level detection device that can improve the accuracy of the detection value of a liquid level detection means.

[Means for Solving the Problems] The liquid level detection device of the present invention has a bottom wall portion, is disposed in a tank, and has a float attached thereto, and a float arm that rotatably supports the float arm. and a fixing means for fixing the housing, the liquid level detecting means having a housing arranged in a closed position on the bottom wall of the tank.

[Operation] Since the fixing means is disposed in close contact with the bottom wall of the tank, the housing of the liquid level detection means fixed to the fixing means is always located at a constant height from the bottom wall of the tank. . Therefore, even if the tank expands or contracts due to fluctuations in the internal pressure inside the tank, the height of the housing from the bottom wall of the tank remains constant, so the float attached to the tip of the float arm keeps the liquid level at a constant level. is detected with high accuracy.

[Effect of the invention] The accuracy of the detection value of the liquid level detection means can be improved.

Therefore, the user can accurately judge the amount of liquid in the tank.

[Example] A liquid level detection device of the present invention will be explained based on an example shown in FIGS. 1 to 3.

FIG. 1 shows an automobile fuel supply device incorporating a liquid level detection device.The automobile fuel supply device 1 supplies fuel from a fuel tank 2 to an internal combustion engine ( (not shown).

The fuel tank 2 has an opening 21 formed therein, a wall 22, a bottom wall 23, and a IIIJP section (not shown) connecting these. It is covered by a cover 24 made of resin. A connector 25 is integrally formed on the cover 24. A lead wire 2G is provided protruding from the connector 25.

When energized, the fuel pump sucks fuel and pumps it to the outside of the fuel tank 2 via the discharge vibrator 31 . The pressure-fed fuel is supplied to the combustion chamber of the internal combustion engine via a fuel injection valve (not shown), and excess fuel is led back into the sub-tank 6 through the return vibe 32. Discharge vibrator 31
A flange member 33 with the same name is provided on the outer periphery of the central portion of the flange member 33 . The discharge vibrator 31 and the return pipe 32 are each made of metal such as 5 pcc, and are insert-molded in the cover 24.

Further, this fuel pump is integrally assembled with the liquid level detection device 4. The liquid level detection device 4 is inserted into the fuel tank 2 through the opening 21 .

The liquid level detection device 4 includes a fuel sender 5 as a liquid level detection means, a sub tank 6 as a fixing means, and a coil spring 7 as a biasing means.

2 and 3 show how the fuel sender 5 is assembled to the sub-tank 6.

The fuel sender 5 has a float 5 floating on the liquid surface of the fuel.
1. Float arm 5 with the float 51 attached to the tip
2, and a housing 53 that rotatably supports the float arm 52 and has sliding resistance (not shown).
has. The output value of the fuel sender 5 changes as the position of the contact that slides on the sliding resistance changes in accordance with the movement of the float 51. Further, in the fuel sender 5, a bracket 54, which is integrally assembled to the housing 53, is assembled to the sub-tank 6 by screws 55 and screws 71-56. And bracket 5
A plurality of holes 51 are formed in the lower end portion of 4.

In addition, the fuel sender 5 may be a fuel level indicator that turns on a lamp when the remaining amount of fuel in the fuel tank 2 becomes low to warn the vehicle occupants.

The sub-tank 6 has a sub-tank main body GO1 made of resin such as polyacetal with an open upper end and a sub-tank cover 61 that closes the opening of the sub-tank main body 60 to accommodate the fuel pump, and is supported by a placket 62.

A locking groove 63 is provided in a predetermined position to protrude from the upper outer peripheral wall of the sub-tank body 60.

On the outer periphery of the sub-tank cover 61, there is a sub-tank main body 6.
0 locking grooves 63 and three claw-like engaging portions 65 that engage with the bracket 62.
is provided. Therefore, the sub tank cover 61 is
It is fixed to the sub-tank main body 60 by placing it over the opening of the sub-tank main body 60 and fitting the claw-like locking portion 64 into the locking groove 63 of the sub-tank main body 60 to lock it in place. The sub-tank cover 61 also has a boss portion 6 that protrudes toward the cover 24 and through which the discharge vibrator 31 is inserted.
6 is integrally formed. Note that the discharge vibrator 31 and the boss portion 66 are slidable in the vertical direction. Further, a bracket 54 is provided on the upper side of the sub-tank cover 61.
A plurality of protrusions 67 are provided to protrude toward the cover 24 for positioning the fuel sender 5 to be fitted into the plurality of holes 57 . Furthermore, sub tank cover 61
A rotation stopper 68 for the nut 56 is provided on the lower side of the nut 56 .

The bracket 62 is formed continuously from the lower end of the cover 24 and is located at three claw-like engaging portions 65 of the sub-tank cover 61.
It is extended downward in the figure at a location corresponding to . A vertically elongated window (not shown) that engages with a claw-like engagement portion 65 of the sub-tank cover 61 is formed in the center of the bracket 62 . This window has a width large enough to fit the claw-like engaging portion 65, is formed long in the vertical direction, and supports the claw-like engaging portion 65 so as to be slidable in the vertical direction. Therefore, the sub-tank 6 is regulated from displacement in the circumferential direction by the bracket 62 and is supported so as to be movable in the vertical direction.

The coil spring 7 is disposed between the flange member 33 of the discharge vibrator 31 and the outer periphery of the boss portion 66 of the sub-tank cover 61. The coil spring 7 urges the sub-tank 6 toward the bottom wall 23 of the fuel tank 2, thereby bringing the bottom wall surface 69 of the sub-tank 6 into close contact with the bottom wall 23 of the fuel tank 2.

The operation of the liquid level detection device 4 of this embodiment will be explained based on FIGS. 1 to 3.

For example, when the fuel tank 2 expands due to fluctuations in the internal pressure within the fuel tank 2, the height of the upper wall portion 22 of the fuel tank 2 rises. In this way, when the height of the wall 22 increases, the cover 2 that closes the opening 21 of the upper wall 22
The height of 4 also rises.

The sub-tank 6 is urged toward the bottom wall portion 23 of the fuel tank 2 by a coil spring 7 disposed between the flange member 33 of the discharge vibrator 31 and the outer periphery of the boss portion 66 of the sub-tank cover 61.

Therefore, the claw-like engaging portion 65 of the sub-tank cover 61 moves downward with respect to the bracket 62 formed continuously on the cover 24. At the same time, the boss portion 66 of the sub-tank cover 61 slides downward relative to the discharge vibe 31 insert-molded in the cover 24, so that the bottom wall surface 69 of the sub-tank 6 is aligned with the fuel tank 2.
It comes into close contact with the bottom wall part 23 of.

Conversely, even if the fuel tank 2 is compressed due to fluctuations in the internal pressure within the fuel tank 2 and the height of the cover 24 is reduced, the coil spring 7 will bias it toward the bottom wall 23 of the fuel tank 2. Therefore, the bottom wall surface 6 of the sub tank 6
9 is in close contact with the bottom wall portion 23 of the fuel tank 2.

That is, the bottom wall surface 69 of the sub-tank 6 is connected to the cover 24.
Regardless of variations in height from the bottom wall 23 of the fuel tank 2, the fuel tank 2 is always in close contact with the bottom wall 24 of the fuel tank 2.

On the other hand, the housing 53 of the fuel sender 5 is connected to the sub-tank cover 61 of the sub-tank 6 via the bracket 54.
It is integrally assembled on the upper side of the.

Therefore, since the bottom wall surface 69 of the sub-tank 6 is always in close contact with the bottom wall 23 of the fuel tank 2 as described above, the height of the housing 53 of the fuel sender 5 is always adjusted to the bottom wall of the fuel tank 2. It will be located at a constant height from the section 23.

Therefore, the resistance value detected by the float 51 attached to the tip of the float arm 52 rotatably supported by the housing 53 is always the resistance value based on the bottom wall portion 23 of the fuel tank 2. Therefore, since the fuel level is detected with high accuracy, even if the pointer of the fuel gauge is at point E, where there is little remaining fuel, the height of the float 51 does not rise, allowing vehicle occupants to check the fuel level. There will be no misunderstanding that there is a large amount remaining. In addition, even if the pointer of the fuel gauge is at the F (full) point, the height of the float 51 does not fall, so the vehicle occupant will not mistakenly believe that the fuel level is low.

(Modification) In this embodiment, the fuel sender is fixed to the side of the sub-tank cover, but it may also be fixed to the side wall of the sub-tank body. However, it is necessary to form a screw hole in the side wall of the sub-tank body. Furthermore, since the amount of fuel secured in the sub-tank is less than in this embodiment, this embodiment is preferable for the fixing location.

Further, as a fixing method, any method such as welding, adhesion, Pol I tightening, etc. can be used.

In this embodiment, the present invention is incorporated into a fuel supply system for an automobile, but the present invention may also be incorporated into a fuel supply system for a vehicle, a ship, an airplane, or the like. Further, the present invention may be incorporated into a fuel supply device of a combustion device.Furthermore, not only fuel but also liquids such as hydraulic oil and water may be used as the liquid.

In this embodiment, the 11 force means is disposed between the flange member 33 of the discharge vibrator 31 and the outer periphery of the boss portion 66 of the sub-tank cover 61, but it urges the sub-tank 6 toward the bottom wall portion 23 of the fuel tank 2. The biasing means may be placed anywhere if possible, and a leaf spring, rubber, or the like can be used as the biasing means.

In this example, a sub-tank was used as the fixing means, but
As the fixing means, a joining member joined to the bottom wall of the tank by welding, gluing, fastening, etc. may be used. As this joining member, a fuel pump, a bracket, etc. can be used.

In this embodiment, a variable resistance type fuel sender is used as the detection means, but a bimetal type fuel sender may be used as the detection means.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an automobile fuel supply system that integrally incorporates a liquid level detection device adopted in an embodiment of the present invention, and Fig. 2 shows the state in which a fuel sender is assembled to a sub-tank. The front view and FIG. 3 are rear views showing the assembly of the fuel sender to the sub-tank. In the diagram 1... Automotive fuel supply device 2... Fuel tank 4
...Liquid level detection device 5...Fuel sender (liquid level detection means) 6...Sub tank (fixing means) 7
...Coil spring 23...Bottom wall village 3 diagram

Claims (1)

[Scope of Claims] 1) (a) A liquid level detection means disposed in a tank having a bottom wall portion and having a float arm to which a float is attached, and a housing that rotatably supports the float arm; (b) disposed in close contact with the bottom wall in the tank;
and fixing means for fixing the housing.