Raindrop detection device

Abstract

A raindrop detection device includes a first fixing member which is fixed to a windshield and has a first engagement portion, an inner housing in which a detection unit is accommodated, an outer housing in which the inner housing is accommodated and which is fixed to the inner housing, a second fixing member having a second engagement portion which is detachably engaged with the first engagement portion of the first fixing member, and a leaf spring which is engaged with the inner housing to press and bias the inner housing toward the windshield. The second fixing member has a leaf-spring biasing portion, which contacts the leaf spring to elastically bias the leaf spring toward the windshield at a predetermined pressing force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which:

FIG. 1 is a partially sectional plan view showing a raindrop detection device when being viewed in a front-rear direction according to an exampled embodiment of the present invention;

FIG. 2 is a partially sectional view showing the raindrop detection device in FIG. 1 when being viewed in an up-down direction;

FIG. 3 is a partially sectional view showing the raindrop detection device in FIG. 1 when being viewed in a left-right direction;

FIG. 4 is a partially sectional view showing the raindrop detection device in FIG. 3 when a first engagement portion of a first fixing unit is omitted;

FIG. 5 is a partially sectional view showing the raindrop detection device in FIG. 3 when leaf-spring engaging portions are indicated in broken line;

FIG. 6 is a graph showing load variations of the raindrop detection device according to the exampled embodiment and a raindrop detection device according to a comparison example due to temperature and humidity; and

FIG. 7 is a graph showing output property variations of the raindrop detection device according to the exampled embodiment and the raindrop detection device according to the comparison example due to temperature and humidity.

Claims

1. A raindrop detection device, comprising: a first fixing member which is fixed to a windshield and has a first engagement portion;a detection unit for optically detecting raindrop adhered to the windshield;an inner housing in which the detection unit is accommodated;an outer housing in which the inner housing is accommodated and which is fixed to the inner housing;a second fixing member having a second engagement portion which is detachably engaged with the first engagement portion of the first fixing member, the second fixing member being detachably engaged with the inner housing to detachably fix the inner housing to the first fixing member; anda leaf spring which is engaged with the inner housing to press and bias the inner housing toward the windshield, whereinthe second fixing member has a leaf-spring biasing portion, which contacts the leaf spring mounted to the inner housing to elastically bias the leaf spring toward the windshield at a predetermined pressing force.

2. The raindrop detection device according to claim 1, wherein a length direction and a width direction of the leaf spring are substantially parallel with a main plane of the windshield.

3. The raindrop detection device according to claim 1, wherein the leaf spring is a flat leaf spring.

4. The raindrop detection device according to claim 1, wherein: the inner housing has a pair of leaf-spring engaging portions by which two ends of the leaf spring are supported; anda substantial middle portion of a length direction of the leaf spring is elastically biased toward the windshield by the leaf-spring biasing portion of the second fixing member.

5. The raindrop detection device according to claim 4, wherein the outer housing has an opening which is arranged at an end surface of a side of the outer housing, the second fixing member being insertable into the outer housing through the opening in such a state that the second fixing member is substantially parallel with a main plane of the windshield.

6. The raindrop detection device according to claim 5, wherein the leaf spring is positioned nearer a side of the windshield than the second fixing member and extends in an insertion direction of the second fixing member.

7. The raindrop detection device according to claim 6, wherein the leaf-spring biasing portion of the second fixing member bends the leaf spring toward the windshield while making a main plane of the leaf spring sliding, when the second fixing member is inserted into the outer housing.

8. The raindrop detection device according to claim 6, wherein a line connecting the second engagement portion of the second fixing member with the leaf-spring biasing portion thereof is substantially parallel with a normal to the windshield.

9. The raindrop detection device according to claim 1, wherein the first fixing member is bonded to the windshield.

10. The raindrop detection device according to claim 4, wherein the leaf-spring engaging portion is arranged at an outer surface of a side wall of the inner housing, and protrudes from the outer surface.

11. The raindrop detection device according to claim 1, wherein the leaf-spring biasing portion is a taper-shaped protrusion, and is arranged at a substantially same position as the second engagement portion in the up-down direction.