Patent Application
20240246515
The present invention relates to a structure of a wiper blade of a wiper for wiping the windshield of a vehicle.
A vehicle wiper mainly includes a supporting body (vertebra) to which a wiper arm for causing a wiper to perform reciprocating arc motion is coupled, and a blade rubber that is held entirely by the supporting body and comes into direct contact with and wipes off rain drops and dust attached to a windshield. To uniformly wipe off the rain drops and the dust, it is necessary for the blade rubber to constantly press the surface of the windshield with uniform force. However, it is difficult for the blade rubber to constantly uniformly press a curved surface of the windshield that changes with the arc motion of the wiper. To obtain sufficient pressing force, it is necessary to increase force of the wiper arm applied to the vertebra. This leads to a problem that the blade rubber is nonuniformly worn out and deteriorated to reduce the service life of the blade rubber. Therefore, to obtain uniform pressing force to the surface of the windshield without increasing the force of the wiper arm, blade rubbers having various cross-sectional structures have been devised.
A cross-sectional structure of a normal blade rubber mainly includes a tip portion that has a thin width and abuts on the surface of the windshield, a fixing portion that includes a protrusion to attach the blade rubber to the vertebra, and an intermediate portion to cause the blade rubber to have elasticity in a vertical direction and a lateral direction. The intermediate portion that has an inverted-triangular cross-section and is hollow or not hollow, is common (Patent Literatures 1 to 5); however, various intermediate portions each having another shape have been proposed (Patent Literatures 6 and 7).
As described above, it is difficult to constantly apply uniform pressure to the curved surface of the windshield that changes with the reciprocation motion of the wiper, only by pressurization by the wiper arm. In particular, in a cross-sectional structure of a blade rubber, the cross-section of which is not hollow, only elasticity of a material of the linear blade rubber is used as pressure to wipe the windshield. Therefore, it is difficult to flexibly follow the change of the surface shape of the windshield, and sufficient wiping performance is not obtainable.
In a structure of a wiper blade according to the present invention, when a frame side is assumed to be an upper side, a neck portion extends in a vertical direction at center, a wing portion extending in a horizontal direction is provided on both sides of an uppermost part of the neck portion for fixation to the frame, and the neck portion extends downward and is coupled to a hollow deformation portion. The cross-sectional shape of the hollow portion is a heart shape with the neck portion as a center line. As a result, the cross-section of the deformation portion has symmetrical curved sides with the neck portion as the center line. The neck portion is coupled to an upper intersection of the curved portions, and a contact portion wiping the windshield extends downward from a lower intersection of the curved portions.
A blade rubber according to the present invention is configured as follows.
A blade rubber to be attached to a frame of a vehicle wiper and to wipe a windshield, includes: a wing portion extending in a horizontal direction to fix the blade rubber to the frame; a neck portion perpendicularly coupled to the wing portion; a deformation portion elastically deformable and coupled to a lower end of the neck portion; and a contact portion provided on a side of the deformation portion opposite to a side provided with the neck portion, and configured to abut on the windshield. The deformation portion internally includes a cavity portion having a heart-shaped cross-section. The neck portion is coupled to an intersection of arc parts of two curved portions surrounded by an outside of the deformation portion and the heart-shaped cavity portion. The contact portion is coupled to an intersection at which the curved portions are coupled at an acute angle.
Further, each of the two curved portions is less in thickness than the neck portion and the contact portion.
Further, the wing portion includes a first wing portion to be inserted into a holding groove of the frame, and a second wing portion abutting on a bottom surface of the frame to fix the blade rubber. A clearance is provided between upper surfaces of the arc parts of the two curved portions in the heart shape and the second wing portion.
With the cross-sectional structure according to the present invention, the curved portions of the deformation portion having the heart-shaped cavity are deformed and crushed in the vertical direction and the lateral direction. As a result, restoring force greater than restoring force by the existing technique occurs. Further, by the action of the deformation portion, the blade is deformed by flexibly following the change of the curved surface of the windshield with the motion of the wiper. This makes it possible to wipe the windshield with more uniform pressing force. Accordingly, as compared with the existing blade rubber, it is possible to largely improve the wiping performance.
An embodiment of the present invention is described in detail below by using an example.
The deformation portion 20 internally includes a cavity portion 22 having a heart-shaped cross-section. As a result, an outside of the deformation portion 20 is formed by two curved portions 24, and the neck portion 16 is coupled to an upper intersection 26 that is an intersection of upper arc parts of the two curved portions 24. Further, a contact portion 30 abutting on a windshield extends downward from a lower intersection 28 at which the heart shape is coupled at an acute angle, at the lower end of the deformation portion 20. The heart shape has characteristics that both sides are formed by curved lines symmetrical about the center line, the upper part has an arc shape, the upper intersection 26 of the curved lines is recessed downward, and the lower intersection 28 protrudes downward. As described below, the shape exerts a large effect in improving its wiping performance.
The blade rubber having the structure according to the present invention is characterized in that large asymmetrical deformation is possible relative to the center line of the heart shape. This is because the curved portions 24 on both sides of the heart shape and the neck portion 16 are coupled at the upper intersection 26, and a thickness of the neck portion 16 is greater than a thickness of most part of the curved portions 24, which causes the curved portions 24 to be deformed easier than the neck portion 16. In other words, by the external force of the wiper arm and the force in the direction opposite to the traveling direction, received from the windshield caused by the lateral motion, the curved portion 24 on the side opposite to the traveling direction side is deformed before the neck portion 16, to incline the whole of the deformation portion 20. As a result, the contact portion 30 is also inclined. When the inclination of the contact portion 30 is further increased, the upper surface of the largely deformed curved portion 24 abuts on a bottom surface of the second wing portion 14, and the curved portion 24 is further crushed and deformed because the curved portion 24 cannot move upward any more. When the deformation is increased, the restoring force by the elasticity of the rubber at a drastically deformed portion is increased, and a downward component thereof acts as force pressing the contact portion 30 downward. In addition, the curved portion 24 on the traveling direction side is also deformed and the restoring force by the elasticity of the rubber is generated, and the downward component thereof contributes to force pressing the contact portion 30 downward. Further, the restoring force by the elastic deformation of the contact portion 30 is added with the restoring force of the curved portions 24 on both sides of the deformation portion 20, and large downward pressing force to the windshield is accordingly given to the tip of the contact portion 30.
In contrast, in the case of the blade rubber having the existing structure without a cavity portion, the intermediate portion having a substantially triangular cross-section is hardly elastically deformed because the intermediate portion is greater in thickness than the neck portion and the contact portion, and elastic deformation mainly occurs on the neck portion and the contact portion. The restoring force by elasticity of the neck portion and the contact portion is obviously less than the restoring force according to the present invention including the curved portions 24.
The magnitude of the pressing force of the blade rubber according to the present invention depends on a width of the upper intersection 26, an interval between the upper surfaces of the arc parts and the second wing portion 14, and the thicknesses of the curved portions 24 (namely, size of cavity portion 22). Therefore, these parameters are determined so as to obtain desired pressing force. Note that, in the present embodiment, the cavity portion 22 having the symmetrical heart shape is described; however, the heart shape may not be symmetrical as long as the heart shape has the curved portions easily deformed right and left.
Further, the deformation portion 20 having the heart-shaped cavity portion 22 can be flexibly deformed in both of the lateral direction and the vertical direction because both sides of the center line can be deformed to different shapes. The deformation portion 20 can react to changes of the curved surface of the windshield with the reciprocation motion of the wiper, like a shock absorber, and can follow large changes. In contrast, in the case of the blade rubber not having the cavity portion as illustrated in
Note that the present invention is described based on the above-described embodiment; however, the present invention is not limited to the embodiment, and it is apparent to those skilled in the art that various modifications and corrections can be made within the spirit of the present invention and the scope of the appended claims. In the above-described embodiment, the cavity is empty (air). Alternatively, for example, as an additional function, a liquid agent such as a water repellent agent may be injected into the cavity so as to seep from the cavity, thereby imparting water repellency to the windshield. Further alternatively, the size of the cavity portion may be increased or decreased depending on the position of the blade rubber in the longitudinal direction, and elasticity may be varied depending on the position.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/017382 | 4/8/2022 | WO |
