A resin member contains a thermoplastic resin and is bonded to another resin member by ultrasonic welding. The resin member includes projections that are projected from a surface of a bonding target section of the resin member and melted by application of contact pressure during the ultrasonic welding. The projections include projections having different projection heights from the surface of the bonding target section.
1. A first resin member, comprising:
a base having a flat surface having an elevation, the flat surface comprising a center position, and
a plurality of projections projected from the flat surface of the base and rising above the elevation,
wherein the flat surface and the plurality of projections bond the first resin member to a second resin member, wherein the plurality of projections melt by contact pressure in an ultrasonic welding process,
wherein the flat surface and the plurality of projections comprise a thermoplastic resin,
wherein the plurality of projections include:
a plurality of central projections arranged around the center position of the flat surface of the first resin member, wherein each central projection is equidistant from the center position, and wherein a distance between each adjacent pair of central projections is the same, and
surrounding projections located further from the center position than the plurality of central projections are located:
wherein the flat surface of the first resin member comprises a region at the elevation, the region is located within a boundary defined by a circle having its center at the center position of the first resin member and its radius equal to a shortest distance between the center position and one of the plurality of central projections;
wherein the plurality of central projections has a first projection height highest among the plurality of projections.
2. The first resin member according to claim 1 , wherein, among the plurality of projections, the first projection height of each central projection is higher than projection heights of the surrounding projections.
3. The first resin member according to claim 1 ,
wherein among the surrounding projections, any first surrounding projection that is more proximal to the center position has a projection height greater than that of a second surrounding projection that is more distal to the center position compared to the first surrounding projection.
4. The first resin member according to claim 2 ,
wherein among the surrounding projections, any first surrounding projection that is more proximal to the center position has a projection height greater than that of a second surrounding projection that is more distal to the center position compared to the first surrounding projection.
5. The first resin member according to claim 1 , wherein the surrounding projections comprise a subset of surrounding projections, wherein each surrounding projection of the subset of surrounding projections is equidistant from the center position, and wherein a distance between each adjacent pair of surrounding projections from the subset of surrounding projections is the same.
6. The first resin member according to claim 2 , wherein the surrounding projections comprise a subset of surrounding projections, wherein each surrounding projection of the subset of surrounding projections is equidistant from the center position, and wherein a distance between each adjacent pair of surrounding projections from the subset of surrounding projections is the same.
7. The first resin member according to claim 3 , wherein the surrounding projections comprise a subset of surrounding projections, wherein each surrounding projection of the subset of surrounding projections is equidistant from the center position, and wherein a distance between each adjacent pair of surrounding projections from the subset of surrounding projections is the same.
8. The first resin member according to claim 4 , wherein the surrounding projections comprise a subset of surrounding projections, wherein each surrounding projection of the subset of surrounding projections is equidistant from the center position, and wherein a distance between each adjacent pair of surrounding projections from the subset of surrounding projections is the same.
9. The first resin member according to claim 1 , wherein the first resin member is a carbon fiber-reinforced plastic member.
10. The first resin member according to claim 2 , wherein the first resin member is a carbon fiber-reinforced plastic member.
11. The first resin member according to claim 4 , wherein the first resin member is a carbon fiber-reinforced plastic member.
12. The first resin member according to claim 3 , wherein the first resin member is a carbon fiber-reinforced plastic member.
13. The first resin member according to claim 1 , wherein a cross-sectional shape of each projection comprises rectangular shape or a dented rectangular shape.
14. The first resin member according to claim 1 , wherein the first projection height of at least one central projection of the plurality of central projections is different from projection heights of the surrounding projections, wherein the first projection height of the at least one central projection is in a range of 0.1 mm to 3.0 mm, and wherein the projection heights of the surrounding projections are in a range from 0.01 mm to 2.9 mm.
15. The first resin member according to claim 1 , wherein the surrounding projections comprises six projections which are arranged around the center position of the flat surface, wherein the six projections are equidistant from the center position, and wherein a distance between each adjacent pair of projections of the six projections is the same.
16. The first resin member according to claim 1 , wherein the second resin member is stably held on the first resin member during the ultrasonic welding process by the plurality of central projections arranged around the center position.
17. A first resin member, comprising:
a plurality of projections projected from a surface of an area of the first resin member, wherein the area bonds the first resin member to a second resin member, wherein the plurality of projections melt by contact pressure in an ultrasonic welding process,
wherein the first resin member comprises a thermoplastic resin,
wherein the plurality of projections include:
a first set of six surrounding projections which are equidistant from a center position of the area of the first resin member, wherein the first set of six surrounding projections defines vertices of a first regular hexagon, and
a second set of six surrounding projections which are equidistant from the center position of the area of the first resin member, wherein the second set of six surrounding projections defines vertices of a second regular hexagon,
wherein a height of the first set of six surrounding projections is greater than a height of the second set of six surrounding projections,
wherein a distance of each projection of the first set of six surrounding projections from the center position is less than a distance of each projection of the second set of six surrounding projections from the center position, and
wherein no vertex of the first regular hexagon is collinear with a pair of opposing vertices of the second regular hexagon.