Oil drain valve, energy accumulation device, hydraulic system and working machine

An oil drain valve, comprising a valve body, a valve core and an elastic element;

• wherein
• the valve body is provided with a first oil port and a second oil port, and the valve core is provided between the first oil port and the second oil port;
• the valve core is communicated with the first oil port and the second oil port, and the valve core is movable in the valve body to switch from a first working position to a second working position;
• the elastic element is provided between a first end of the valve core and the valve body, the first end of the valve core is communicated with the first oil port, and a second end of the valve core is communicated with the second oil port;
• in response to hydraulic oil in the oil drain valve flows from the first oil port to the second oil port, the valve core is configured to switch from the second working position to the first working position under an action of the elastic element;
• in response to the hydraulic oil in the oil drain valve flows from the second oil port to the first oil port, the valve core is configured to compress the elastic element and switch from the first working position to the second working position;
• and
• a flow quantity of the oil drain valve in response to the valve core operates in the second working position is less than a flow quantity of the oil drain valve in response to the valve core operates in the first working position;
• wherein an oil passage is provided in the valve body;
• a first back cavity is formed between the first end of the valve core and the valve body, and the elastic element is provided in the first back cavity;
• the oil passage is configured to communicate with the first back cavity and the first oil port to form a first feedback oil path;
• and
• the second end of the valve core is provided with a cavity communicated with the second oil port;
• a side wall of the cavity is provided with a first oil hole, and the cavity is communicated with the first oil port through the first oil hole;
• an open degree of the first oil hole in response to that the valve core operates in the first working position is larger than an open degree of the first oil hole in response to that the valve core operates in the second working position;
• wherein the valve body comprises a valve seat and a valve sleeve;
• the first oil port and the second oil port are both provided on the valve seat, and the valve seat is provided with a valve core cavity;
• the valve sleeve is fixedly provided in the valve core cavity, and the valve core is slidably provided in the valve sleeve;
• a second oil hole is provided on a side wall of the valve sleeve, and the second oil hole is communicated with the first oil port and the first oil hole.