Die cast sub-frame
A pound or number sign shaped (#-shaped) die cast sub-frame includes first and second horizontal members and first and second vertical members. The sub-frame has four arm mounting portions provided at four corners thereof, respectively. The arm mounting portion is a die cast part obtained near a communication portion of a runner formed in a die casting machine. Generally triangular bulged portions are formed at junction portions where the first horizontal member meets the first and second vertical members. Each junction portion has increased width. The junction portion is a die cast obtained within a cavity of increased width of the die casting machine. The bulged portion is pierced to provide a hole. The bulged portion having the hole formed therein is to be mounted to a small vehicle component.
1. A die cast sub-frame for use in mounting a vehicle component to a vehicle body, the sub-frame comprising:
a body portion; and
a mounting portion adapted to be attached to the vehicle component, the mounting portion being provided on the body portion;
the sub-frame being produced by a die casting process and a die casting machine having formed therein a gate, runners communicating with the gate, and a cavity communicating with a communication portion of the runner, the die casting process comprising the steps of:
positioning the mounting portion in correspondence with the communication portion;
flowing molten alloy through the runner into the cavity, wherein solidification occurs at the farthest portion of the alloy from the communication portion;
applying pressure to the nearest part of the alloy to the communication portion, thereby compressing the nearest part into a dense cast structure having greater mechanical strength than the rest of the die cast sub-frame.