Hydraulic control valve, hydraulic control system, and transmission

A hydraulic control valve, comprising a valve body, a slidable valve cartridge, and a pressing mechanism, wherein:

• a valve hole, a first oil supply port, a second oil supply port, and an oil discharge port are formed at the valve body, each of the first oil supply port, the second oil supply port, and the oil discharge port being in communication with the valve hole;
• both the slidable valve cartridge and the pressing mechanism are accommodated within the valve hole;
• the slidable valve cartridge has a small end close to an end of the valve hole and a large end abutting against the pressing mechanism;
• the pressing mechanism is disposed at another end of the valve hole;
• and
• the hydraulic control valve has a first operation state and a second operation state, wherein:
• in the first operation state, a total oil supply pressure on the slidable valve cartridge from the first oil supply port and the second oil supply port is small than or equal to a pressing force from the pressing mechanism, and the first oil supply port, the second oil supply port, and the oil discharge port are in no communication with each other;
• and
• in the second operation state, the total oil supply pressure on the slidable valve cartridge from the first oil supply port and the second oil supply port is greater than the pressing force from the pressing mechanism, and the slidable valve cartridge moves towards the pressing mechanism to bring the first oil supply port into communication with the oil discharge port via the valve hole.