Shop Manual

20-59
 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”.