Hard fork usually doesn't create new coin, unless the community can't agree decide to split. For example, BCH had hard fork that raise block size from 8MB to 32MB. But it doesn't lead to new coin being created.
Is BCH not a new coin as a result of chain split after the community altercations?
There should be a chain split in a hard fork, but that should be if there is a consensus. With bitcoin cash (BCH), there was no consensus, but Bitcoin Cash developers moved to create another coin themselves, but bitcoin is still bitcoin.
Assuming if BCH receive up to 70% of support that signals for the upgrade instead of the 37% that it had, there will be a chain split. The old chain which is still the one bitcoin is using now will be left for the new one and the new coin will be BCH. It may not be called BTC but remain as BTC but there will be a chain split and a new coin. BCH is not a new coin, it supposed not to be created because there was no consensus.
If there is a chain split, BCH of today supposed to be BTC as the old chain would be left, but no new coin created but BCH which is an altcoin that was created after no consensus.
But it is possible that if there was more support for BCH and there was chain split and new bitcoin was created, some miners and nodes may continue to support the old bitcoin just like what happened to ETH which was newly created after an upgrade while some miners and nodes stayed on the old chain and named the old ETH as ETHW (old ETH). I think it happened with ethereum classic and ETH. I just use the altcoins as an example because no upgrade that I know about bitcoin that caused chain split.
With hard fork, bitcoin will have to have a chain split, making it non-backward compatible, new blockchain will be created, nodes have to upgrade and move to the new chain.
Soft fork is backward compatible and no chain split is the difference it has with hard fork.
Do not let BCH articles you see online to confuse you, there was no new coin (no new bitcoin) that was created.