Iron species preform
View Patent ↗An iron species preform for forming a metal matrix composite is inserted in an aluminum species alloy member to be cast-in. The aluminum species alloy member has bearing faces having a section in a semicircular arc shape. An inner peripheral face of the iron species preform is provided with a plurality of inner side grooves. The inner side groove includes flat portions and groove bottom portions continuous to two end edges continuous to the inner peripheral face and opposed to each other. In a cast-in step, shrinkage in a peripheral direction accompanied by solidifying a melted aluminum species alloy is uniformly received by the respective inner side grooves, movement in the peripheral direction is restrained, a clearance at an interface can be prevented from being brought about, so that a cast-in performance is excellent, and stable bonding strength and close contact of the interface can be ensured.
1. An iron species preform for forming a metal matrix composite by casting-in the iron species preform with an aluminum species alloy base material, the iron species preform comprising:
an inner peripheral face having a section in a semicircular shape and continuously extending along a direction of a center axis; and
a plurality of inner side grooves formed on the inner peripheral face at spaces in a peripheral direction, each inner side groove continuously extending along the direction of the center axis and having a section of U-shape opened to the center axis,
wherein each inner side groove includes:
two flat portions opposed to each other and having base ends respectively continuous to end edges continuous to the inner peripheral face; and
a groove bottom portion continuously formed between depth ends of the two flat portions, and
when a length from the base end to the depth end of the flat portion is A, a groove width of the inner side groove is B, a radius of curvature of a sectional shape of the groove bottom portion orthogonal to the center axis is C, an angle of inclination of the flat portion relative to a reference line in a linear shape extended from the center axis to a center of the groove width is E, and a space between the centers of the respective groove widths of the inner side grooves contiguous to each other is F, then
0.1 mm≦A≦1.0 mm,
0.5 mm≦B≦10.0 mm,
C/B≦ 1.5,
E≦5°, and
F/B≦ 5.
2. The iron species preform according to claim 1 , when the radius of curvature of the sectional shape of the groove bottom portion orthogonal to the center axis is C, then
0.2B≦C≦B.
3. The iron species preform according to claim 1 , wherein a portion at which the two end edges continuous to the inner peripheral face and the flat portion are continuous is a smoothly continuous curved face or a faced shape.
4. The iron species preform according to claim 1 , when the space between the centers of the respective groove widths of the inner side grooves contiguous to each other is F, then
1.5B≦F≦5B.
5. The iron species preform for forming a metal matrix composite according to claim 1 , wherein the iron species preform comprises an iron species powder sintered member.
6. A structure of a journal portion in which the iron species preform according to claim 1 is cast-in with an aluminum species alloy base material having a bearing face in a recess shape having a section in a semicircular arc shape along the inner peripheral face of the iron species preform and continuously extending along the direction of the center axis.
7. The iron species preform according to claim 1 , when the radius of curvature of a sectional shape of the groove bottom portion orthogonal to the center axis is C, then
0.25B≦C≦B.