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 an end close to an end of the valve hole and a part that has a greater diameter than the end close to the end of the valve hole and abuts 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:
• the oil discharge port directly leads to an oil sump;
• wherein the slidable valve cartridge further comprises:
• a first pressure sensing end configured to sense an oil supply pressure from the first oil supply port, the first pressure sensing end being an annular surface between the end of the slidable valve cartridge and the part of the slidable valve cartridge;
• and
• a second pressure sensing end configured to sense an oil supply pressure from the second oil supply port, the second pressure sensing end being a small end surface of the slidable valve cartridge;
• and
• in the first operation state, a force on the slidable valve cartridge resulting from a total oil supply pressure on the slidable valve cartridge from the first oil supply port and the second oil supply port is smaller 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 not in communication with each other;
• and
• in the second operation state, the force on the slidable valve cartridge resulting from 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.