As abovementioned, the manual pump oil ports that under oil output status are connect to the valve sleeve oil ports that flow to steering cylinder, respectively; at the same time, the manual pump oil ports that are under the status of oil intake are connect to valve sleeve oil ports that flow to steering oil pump, respectively. When the faults of engine or oil pump result in the output of steering oil pump stop, the manual pump is intakes oil from oil tank due to the pressure and transmit the oil to steering cylinder that manipulate the steering operation, in such way, the necessary steering operation can still be maintained.
The other function of manual pump is regulating the output oil during operation period. In fact, the oil come from the steering oil pump must pass through the manual pump, because the steering wheel of interior gear of manual pump will forward one teeth when it rotate 1/7 circle, the interior gear push to output the corresponding oil, the oil output flow is direct proportion to the steering angle of steering wheel. When faults occurred in the engine or steering cylinder, the manual pump still has such function, so the normal oil output can still be maintained.
The comparison between cycloidal pump and steering gear manual pump The intake oil ports and the output oil ports are independent in the cycloidal pump. When the oil pump shaft turns to the position shown in the figure below, the oil pumps will intake oil from intake oil port and output oil from output port. The operation sequence is shown in 2 6 below. In manual pump, the input/output ports of oil pump are distributed in the gear tooth of interior gear.
When the oil pump rotates, the oil port shown in figure below will connect to steering oil pump according to the step 2 and step 3 and connect to steering cylinder according to the step 5 and step 6, which will transmit the oil to oil cylinder and the 7 holes independently and uniformly intake and output oil. The function of spring lamination X type spring lamination is composed of three-leaf spring, which is shown in figure below. The X type spring lamination installed in the valve sleeve and valve cartridge. When the steering wheel turns to another side, the valve cartridge compresses the spring lamination.
Because the X type spring lamination increase the angle difference between the valve sleeve and valve cartridge, which make the valve sleeve oil port connects to valve cartridge oil port, so the oil will pass through oil port and flow into steering cylinder. When the steering wheel stops turn, the manual pump will also stop turn, so the oil channel that flows to steering cylinder is closed and the oil pressure increases until the main overflow valve opens and the oil is output.
To avoid the oil pressure increase unnecessarily, the spring lamination returns to original status, which make there has no angle difference between the valve cartridge and valve sleeve, then the same situation has mentioned in the “When the steering wheel doesn’t turn”. 20-59