sacrifice
軷 centers on a ritual sacrifice, specifically an ancient practice of offering to the gods of the road before a journey.
軷 combines 車 (vehicle, cart) with 犮, which likely contributes the sound. The character refers to a road sacrifice where a cart was used in the ritual.
A cart (車) is used in a roadside sacrifice, with the right side 犮 suggesting the ritual action. Picture an ancient cart being offered to the road gods before a journey.
For ハツ, imagine a hat being placed on the cart as part of the sacrifice: hat -> ハツ, and the cart is blessed for the road.