TECHNICAL FIELD

The present invention relates to a technical field of a foreign substance removing device that cleans an object to be cleaned by ejecting a fluid from a nozzle.

BACKGROUND ART

A structure such as a vehicle is provided with various structure bodies, and among these structure bodies, it is desirable to remove foreign substances such as moisture, mud, and dust in order to ensure a good visibility for an in-vehicle camera, a vehicle lamp, and a rearview mirror, for example.

For example, although the in-vehicle camera is used as a device for displaying an image on a display in order to check the rear of the vehicle or check a position outside the vehicle that is difficult for a driver to see, an imaging portion may be contaminated by the mud spattered during traveling of the vehicle, and water droplets or the like adhering to the vehicle during the traveling in the rain or the like, so that the image displayed on the display may become blurred and the checking may be hindered.

In order to prevent such a problem, for example, there has been known a foreign substance removing device that removes foreign substances such as moisture, mud, dust, or the like adhering to an object to be cleaned by ejecting a fluid, for example, high-pressure air from a nozzle to the object to be cleaned such as an in-vehicle camera (for example, see Patent Literature 1).

In the foreign substance removing device described in Patent Literature 1, by moving a piston in a first direction in which the fluid is sent out with respect to the cylinder, for example, air is generated as high-pressure air, and the high-pressure air is ejected toward the object to be cleaned, so that the mud and the water droplets are blown away to eliminate contamination of the object to be cleaned.

The foreign substance removing device that eliminates the contamination of the imaging portion with the fluid such as the high-pressure air has advantages in that a liquid storage tank is not required and the ejected fluid does not remain in the imaging portion, as compared with a foreign substance removing device that ejects a high-pressure fluid such as water to eliminate the contamination.

CITATION LIST

Patent Literature

[Patent Literature 1]: WO 2015/159763

SUMMARY OF INVENTION

Technical Problem

However, in the foreign substance removing device described in Patent Literature 1, the piston is moved with respect to the cylinder at a high speed to generate the high-pressure fluid (high-pressure air), and an urging spring, for example, a compression coil spring is used to move the piston at a high speed. Accordingly, the piston is moved at the high speed by the compression of the compressed urging spring.

However, since the piston is moved by an urging force of the urging spring, a tip end surface of the piston may contact with an inner surface of the cylinder depending on the urging force of the urging spring or the like, and an operation noise due to the contact may be generated. There is a possibility that the operation sound is recognized as an abnormal noise by a user, for example, a driver or a passenger of a vehicle, and in this case, the driver or the passenger may feel uncomfortable, and vibration or the like may occur depending on a degree of contact.

An object of the present invention is to solve the above-described problems and to prevent contact between a piston and a cylinder when the piston is moved.

Solution to Problem

According to a first aspect of the present invention, there is provided a foreign substance removing device including:

a cylinder including a piston support portion of which an internal space is formed as a moving space;

a piston movably supported by the cylinder and configured to send out a fluid that has flowed into the cylinder;

a nozzle configured to eject the fluid sent out by the piston toward an object to be cleaned;

an urging spring configured to urge the piston; and

a moving mechanism configured to apply a moving force to the piston,

wherein a direction in which the fluid is sent out is a first direction of a moving direction of the piston,

wherein the piston is moved in the first direction by an urging force of the urging spring,

wherein the piston includes an operation portion that is moved in the moving space,

wherein the operation portion is formed with a convex portion or a concave portion,

wherein the piston support portion is formed with an insertion concave portion into which the convex portion is capable of being inserted or an insertion convex portion which is capable of being inserted into the concave portion, and

wherein a compression space of the fluid is formed in the moving space in a state in which the piston is moved in the first direction and the convex portion or the insertion convex portion is inserted into the insertion concave portion or the concave portion.

As a result, when the piston is moved in the first direction, the convex portion or the insertion convex portion is inserted into the insertion concave portion or the concave portion, and the compression space of the fluid is formed in the moving space, so that an action of a damper caused by the compressed fluid is generated with respect to the piston.

In the foreign substance removing device according to a second aspect of the present invention, it is preferable that the convex portion or the insertion convex portion is formed into a tubular shape.

As a result, the convex portion or the insertion convex portion having the tubular shape is inserted into the insertion concave portion or the concave portion, and airtightness of the compression space is increased.

In the foreign substance removing device according to a third aspect of the present invention, it is preferable that the operation portion is formed with the concave portion, and the piston support portion is formed with the insertion convex portion.

As a result, it is possible to reduce a size of the piston support portion in the moving direction of the piston.

In the foreign substance removing device according to a fourth aspect of the present invention, it is preferable that the concave portion is formed into an annular shape, the insertion convex portion is formed into a tubular shape, and a portion on an inner side of the concave portion of the piston is provided as an insertion portion to be inserted into an inner side of the insertion convex portion.

As a result, when the piston is moved toward the first direction side, the insertion convex portion of the cylinder is inserted into the concave portion of the piston, and the insertion portion is inserted into the inner side of the insertion convex portion.

In the foreign substance removing device according to a fifth aspect of the present invention, it is preferable that a seal ring is attached to an outer peripheral portion of the insertion portion or an inner peripheral portion of the insertion convex portion.

As a result, when the insertion portion is inserted into the inner side of the insertion convex portion, the insertion portion and the insertion convex portion are sealed by the seal ring.

In the foreign substance removing device according to a sixth aspect of the present invention, it is preferable that a seal member that slides on an inner peripheral surface of the cylinder when the piston is moved is attached to an outer peripheral portion of the operation portion.

As a result, the piston and the cylinder are sealed by the seal member when the piston is moved.

According to a seventh aspect of the present invention, there is provided a foreign substance removing device including:

a cylinder into which a fluid flows; a piston movably supported by the cylinder and configured to send out the fluid that has flowed into the cylinder;

a seal member attached to the piston and slid on an inner peripheral surface of the cylinder when the piston is moved;

a nozzle configured to eject the fluid sent out by the piston toward an object to be cleaned;

an urging spring configured to urge the piston; and

a moving mechanism configured to apply a moving force to the piston,

wherein a direction in which the fluid is sent out is a first direction of a moving direction of the piston,

wherein the piston is moved in the first direction by an urging force of the urging spring, and

wherein an inclined portion whose diameter decreases as it goes in the first direction is formed as a part of an inner peripheral surface of the cylinder.

As a result, a frictional force between the inner peripheral surface of the cylinder and the seal member is increased by the inclined portion.

In the foreign substance removing device according to an eighth aspect of the present invention, it is preferable that a large-diameter portion having a constant diameter is formed as a part of the inner peripheral surface of the cylinder, a small-diameter portion having a constant diameter is formed as a part of the inner peripheral surface of the cylinder, and the inclined portion is positioned between the large-diameter portion and the small-diameter portion.

As a result, the pressure applied from the large-diameter portion and the small-diameter portion to the seal member is constant, and a large frictional force is generated between the small-diameter portion and the seal member.

In the foreign substance removing device according to a ninth aspect of the present invention, it is preferable that the cylinder is formed with a stopper surface that is capable of contacting a tip end surface of the piston when the piston is moved in the first direction, and the inclined portion is formed to be continuous with the stopper surface.

As a result, there is no other surface between the inclined portion and the stopper surface.

In the foreign substance removing device according to a tenth aspect of the present invention, it is preferable that the cylinder includes a piston support portion supporting the piston and a connecting protrusion portion continuous with the piston support portion, the connecting protrusion portion is formed into a tubular shape, the fluid is sent out from the connecting protrusion portion, and an axial direction of the connecting protrusion portion coincides with the moving direction of the piston.

As a result, the fluid is sent out from the connecting protrusion portion whose axial direction coincides with the moving direction of the piston.

In the foreign substance removing device according to an eleventh aspect of the present invention, it is preferable that the cylinder includes a piston support portion supporting the piston and a connecting protrusion portion continuous with the piston support portion, the connecting protrusion portion is formed into a tubular shape, the fluid is sent out from the connecting protrusion portion, and an axial direction of the connecting protrusion portion is a direction orthogonal to the moving direction of the piston.

As a result, the axial direction of the connecting protrusion portion and the moving direction of the piston are orthogonal to each other.

According to a twelfth aspect of the present invention, there is provided a foreign substance removing device including:

a cylinder into which a fluid flows;

a piston movably supported by the cylinder and configured to send out the fluid that has flowed into the cylinder;

an elastically deformable annular seal member attached to an outer peripheral portion of the piston and slidable on an inner peripheral surface of the cylinder when the piston is moved;

a nozzle configured to eject the fluid sent out by the piston toward an object to be cleaned; and

a moving mechanism configured to apply a moving force to the piston,

wherein a direction in which the fluid is sent out is a first direction of a moving direction of the piston, and a direction opposite to the first direction is a second direction of the moving direction of the piston,

wherein a check valve configured to regulate flow of the fluid toward a second direction side is arranged in a flow path of the fluid in a first direction side of the piston,

wherein the seal member is formed with a groove portion opened in the first direction, and

wherein when the piston is moved, the seal member is elastically deformed or elastically restored by a difference of internal pressure in spaces on opposite sides of the cylinder, the seal member being sandwiched between the spaces.

As a result, when the piston is moved in the first direction, the seal member is pressed against and slid on the inner peripheral surface of the cylinder by the pressure in the direction in which the groove portion expands, whereas when the piston is moved in the second direction, the seal member is elastically deformed by the pressure in the direction in which the groove portion is narrowed so as to form the gap between the seal member and the inner peripheral surface of the cylinder.

In the foreign substance removing device according to a thirteenth aspect of the present invention, it is preferable that at least a part of the groove portion is positioned outside an outer peripheral surface of the piston.

As a result, when the piston is moved in the first direction, the air easily enters the groove portion, the pressure in the direction in which the groove portion expands is applied to the seal member, and the seal member is easily pressed against the inner peripheral surface of the cylinder.

In the foreign substance removing device according to a fourteenth aspect of the present invention, it is preferable that the cylinder includes a piston support portion supporting the piston and a connecting protrusion portion continuous with the piston support portion, the connecting protrusion portion is formed into a tubular shape, the fluid is sent out from the connecting protrusion portion, a pipe is connected to the connecting protrusion portion, and the check valve is arranged in the pipe.

As a result, the check valve is arranged in the pipe connecting the nozzle and the cylinder.

In the foreign substance removing device according to a fifteenth aspect of the present invention, it is preferable that the cylinder includes a piston support portion supporting the piston and a connecting protrusion portion continuous with the piston support portion, the connecting protrusion portion is formed into a tubular shape, the fluid is sent out from the connecting protrusion portion, and the check valve is arranged in the connecting protrusion portion.

As a result, since the check valve is arranged in a part of the cylinder, a dedicated member for arranging the check valve is not required.

In the foreign substance removing device according to a sixteenth aspect of the present invention, it is preferable that an axial direction of the connecting protrusion portion coincides with the moving direction of the piston.

As a result, the air is sent out from the connecting protrusion portion whose axial direction coincides with the moving direction of the piston.

Advantageous Effects of Invention

According to the present invention, when the piston is moved in the first direction, the convex portion or the insertion convex portion is inserted into the insertion concave portion or the concave portion to form the compression space of the fluid in the moving space, an action of a damper caused by the compressed fluid is generated with respect to the piston, so that it is possible to prevent contact between the piston and the cylinder when the piston is moved.

