Welded structure and manufacturing method thereof

1. A welded structure comprising:

a first member having a spherical surface part which is formed in a spherical surface shape; and

a second member which is formed in a plate shape;

wherein a part of an end face of the second member before laser welding is performed is formed to be a contact end face having a contact part with which a part of the spherical surface part is contacted;

wherein the second member is formed with a joining part including the contact end face, the joining part being joined to the spherical surface part by laser welding;

wherein at least before laser welding is performed, a plate thickness of the joining part is thinner than a plate thickness of a portion of the second member except the joining part; and

wherein the spherical surface part of the first member and the end part of the second member are joined to each other by laser welding.

2. The welded structure according to claim 1 , wherein the second member comprises two third members which are formed in a plate shape and are laminated so as to abut with each other.

3. The welded structure according to claim 2 , wherein

the first member is a spherical body, an entirety of which is the spherical surface part, and

the second member is a gimbal spring.

4. The welded structure according to claim 2 , wherein the spherical surface part is joined to the joining part by laser welding and thereby the two third members and the spherical surface part are joined to each other and the two third members are joined to each other.

5. The welded structure according to claim 4 , wherein

thicknesses of the two third members in the joining part are equal to each other,

abutting faces of the two third members and a center of curvature of the spherical surface part are substantially coincided with each other in a thickness direction of the second member, and

the spherical surface part is joined to the joining part.

6. The welded structure according to claim 4 , further comprising a cut-out part which is formed in the joining part of one of the two third members, the cut-out part being penetrated in a thickness direction of the third member and being opened on a side of the contact end face,

wherein the two third members and the spherical surface part are joined to each other and the two third members are also joined to each other.

7. The welded structure according to claim 6 , wherein

thicknesses of the two third members in the joining part are equal to each other, and

abutting faces of the two third members and a center of curvature of the spherical surface part are substantially coincided with each other in the thickness direction of the second member.

8. The welded structure according to claim 1 , wherein

the second member is formed in a frame shape,

the contact end face is formed at an inner peripheral end of the second member, and

the joining part is formed in a range from the inner peripheral end of the second member to its outer peripheral end.

9. The welded structure according to claim 1 , wherein

the second member is a gimbal spring which is structured of two plate springs laminated on each other,

the gimbal spring is formed in a substantially square frame shape having four sides each of which is provided with a spring part,

the joining part is formed at a corner part of each of four corners of the gimbal spring,

the first member is made of a spherical body,

a plate thickness of the joining part is thinner than a plate thickness of the spring part of the gimbal spring and is smaller than a diameter of the spherical body, and

four spherical bodies are respectively joined to the contact end faces which are provided on inner sides of the corner parts of the four corners of the gimbal spring by laser welding.

10. The welded structure according to claim 9 , wherein

the gimbal spring is structured of two plate springs having the same width and the same thickness which are laminated so as to abut with each other,

the joining part of one of the two plate springs is formed with a cut-out part for exposing the joining part of the other plate spring abutted with the spherical body, and

the spherical body and the joining part of the other plate spring are welded to each other.

11. The welded structure according to claim 9 , wherein the gimbal spring is a gimbal spring for swingably holding a movable module on which a lens for photographing and an imaging element are mounted through the four spherical bodies.

12. A manufacturing method of a welded structure which is formed such that a spherical surface part of a first member having the spherical surface part formed in a spherical surface shape and an end part of a second member formed in a plate shape are joined to each other by laser welding, the manufacturing method comprising:

previously forming a contact part with which a part of the spherical surface part is contacted in a part of an end face of the second member as a contact end face before laser welding is performed;

previously forming a joining part including the contact end face in the second member which is structured of two third members formed in a plate shape and laminated so as to abut with each other;

at least before laser welding is performed, setting a plate thickness of the joining part to be thinner than a plate thickness of a portion of the second member except the joining part; and

joining the spherical surface part to the joining part by laser welding and thereby the two third members and the spherical surface part are joined to each other and the two third members are joined to each other.

13. The manufacturing method of a welded structure according to claim 12 , wherein a laser is irradiated from both sides in a thickness direction of the second member in a state that abutting faces of the two third members and a center of curvature of the spherical surface part are substantially coincided with each other in the thickness direction of the second member and thereby the spherical surface part is joined to the joining part.

14. The manufacturing method of a welded structure according to claim 12 , wherein

previously forming a cut-out part in the joining part of one of the two third members, the cut-out part penetrating in a thickness direction of the third member and opening a contact end face side of the joining part, and

a laser is irradiated to the cut-out part from a side of the one of the two third members formed with the cut-out part in the thickness direction of the second member and thereby the two third members and the spherical surface part are joined to each other and the two third members are also joined to each other.

15. The manufacturing method of a welded structure according to claim 12 , wherein

the second member is a gimbal spring which is structured of two plate springs laminated on each other,

the gimbal spring is formed in a substantially square frame shape having four sides each of which is provided with a spring part,

the joining part is formed at a corner part of each of four corners of the gimbal spring,

the first member is made of a spherical body,

a plate thickness of the joining part is thinner than a plate thickness of the spring part of the gimbal spring and is smaller than a diameter of the spherical body, and

four spherical bodies are respectively joined to the contact end faces which are provided on inner sides of the corner parts of the four corners of the gimbal spring by laser welding.

16. The manufacturing method of a welded structure according to claim 15 , wherein

the gimbal spring is structured of two plate springs having the same width and the same thickness which are laminated so as to abut with each other,

the joining part of one of the two plate springs is previously formed with a cut-out part for exposing the joining part of the other plate spring abutted with the spherical body, and

a laser is irradiated to the cut-out part from a side of the one of the two plate springs formed with the cut-out part and thereby the spherical body and the joining part of the one of the two plate springs are welded to each other and the spherical body and the joining part of the other plate spring are welded to each other.