Dual-mode active rear-wheel steering device

A dual-mode active rear-wheel steering device, comprising:

• an outer casing;
• a main shaft;
• an intermediate gear;
• a planetary gear coupling mechanism;
• a transmission gear;
• and
• a mode switching assembly;
• wherein a steering motor is fixedly provided on the outer casing, and a first input gear is coaxially arranged with and fixed on an output end of the steering motor;
• the main shaft is rotatably arranged in a middle portion of the outer casing;
• one end of the main shaft is connected to a first rear-wheel motion conversion mechanism through a cylindrical two-stage gear transmission system to drive a first rear wheel to steer, and the other end of the main shaft is connected to a second rear-wheel motion conversion mechanism through the planetary gear coupling mechanism to drive a second rear wheel to steer;
• the intermediate gear is coaxially arranged with and fixed on the main shaft;
• and coaxially arranged with the cylindrical two-stage gear transmission system, and meshes with the first input gear;
• the planetary gear coupling mechanism comprises a sun gear, a plurality of planetary gears, a planetary carrier, an inner ring gear sleeve, a first inner ring gear, a second inner ring gear and a plurality of pin shafts;
• wherein the sun gear is coaxially arranged with and fixed at the other end of the main shaft;
• the inner ring gear sleeve is rotatably arranged inside the outer casing;
• the first inner ring gear is provided at one side of the inner ring gear sleeve, and is concentric with the sun gear;
• the plurality of planetary gears are uniformly provided outside the sun gear in a circumferential direction, and respectively mesh with the sun gear and the first inner ring gear;
• the planetary carrier is coaxially arranged with the sun gear in spaced manner, and the planetary carrier and the second rear-wheel motion conversion mechanism are coaxially connected to drive the second rear wheel to rotate;
• one end of each of the pin shafts rotatably passes through the corresponding planetary gear, and the other end of each of the pin shafts is fixedly provided on the planetary carrier;
• and
• the second inner ring gear is provided on the other side of the inner ring gear sleeve;
• wherein the transmission gear is coaxially arranged with and fixed on the main shaft, and is provided between the sun gear and the intermediate gear;
• one end of the mode switching assembly is coaxially provided with a second input gear that meshes with the transmission gear, and the other end of the mode switching assembly is coaxially provided with a second output gear that meshes with the second inner ring gear, which is configured to selectively drive or lock the first inner ring gear;
• wherein when the mode switching assembly is disconnected, the first inner ring gear is locked to the outer casing by the mode switching assembly, and the planetary carrier is driven only by the sun gear on the main shaft, and then the second rear-wheel motion conversion mechanism is driven to operate;
• when the mode switching assembly is connected, the main shaft drives the sun gear and the first and second inner ring gears in the mode switching assembly to realize the speed coupling, thereby driving the second rear-wheel motion conversion mechanism.