Liquid level detecting device with arm fixing portion having holding groove for receiving float arm

1. A device comprising:

a sensor housing;

a holder which is held rotatably by the sensor housing;

an arm fixing portion provided in the holder;

a float arm which has a base portion fixed to the holder by the arm fixing portion;

a float which is attached to a tip portion of the float arm and varies in position following a surface level of liquid stored in a tank;

a magnet provided in the holder; and

a Hall element which is provided in the sensor housing and detects a displacement of the magnet of the holder,

wherein the arm fixing portion comprises:

a lock hole configured to receive a lock end portion of the float arm, the lock end portion having a bending shape;

a holding portion having a holding groove configured to receive the float arm; and

a retaining portion having a claw configured to lock on a circumferential surface of the float arm that is fitted in the holding groove;

wherein the holding portion has a holding piece that extends parallel with a front surface of the holder and thereby forms the holding groove; and

wherein the holding piece has a holding projection that projects toward the front surface of the holder so that a projection length of the holding projection increases gradually as the holding piece goes away, along a longitudinal direction of the holding groove, from the lock hole.

2. The device according to claim 1 , wherein the holding projection has a holding surface that is inclined so as to come closer to the front surface of the holder as the holding projection goes toward an opening of the holding groove.

3. The device according to claim 2 , wherein the holding surface is inclined so that a projection length of the holding surface in a direction of a rotation axis of the holder increases as the holding surface goes toward the opening of the holding groove.

4. The device according to claim 3 , wherein the holding projection has a guide surface which is adjacent to the holding surface and which is arranged closer to the opening of the holding groove than the holding surface; and

wherein the guide surface is inclined so that a projection length of the guide surface in the direction of the rotation axis of the holder decreases as the guide surface goes toward the opening of the holding groove.

5. The device according to claim 1 , wherein the lock portion extends from the holder so as to have a flexible cantilever arm structure.

6. The device according to claim 1 , wherein the tank is a fuel tank installed in a vehicle for storing fuel as the liquid, and the device is used for detecting a surface level of the fuel in the fuel tank.

7. The device according to claim 1 ,

wherein, in the longitudinal direction, a length of the holding piece is greater than a length of the claw.