13
2) Oil refilling valve
A. Structure (see Figure 7)
The oil refilling valve mainly comprises pressure valve nut, seal nut, valve seat, valve spool (connecting rod
ball), spring, spring seat, filter and O-ring. The oil refilling mechanism is installed at the bottom of the cylinder
block mounting position (see the structure diagram of pump hydraulic end), and the two O-rings on the valve
must be intact for good sealing performance upon installation. The connecting rod ball shall be inserted into the
valve seat hole, and the ball and hole shall be tightly sealed. The connecting rod body is provided with a spring,
spring seat and two lock nuts, and the connecting rod ball can axially run out under force. In addition, the
cross-drilled hole on the outer ring of valve seat is used as an oil-liquid makeup channel. In order to refill clean
oil, the external ring of the valve is provided with a filter.
1
2
3
4
5
6
7
8
9
10
11
7
160 mesh
Filter
BYF-05
6
5
Subassembly
Connecting rod ball
BYF-04
4
45
Valve seat
BYF-03
3
45
Pressure valve nut
BYF-02
2
Q235-A
Sealing nut
BYF-01
1
GB3452.1-1982
O ring 16*1.8
NBR
GB3452.1-1982
O ring 25.8*2.65
NBR
8
BYF-06
Spring
60Si2Mn
9
BYF-07
Spring seat
Q235-B
10
BYF-08
Gasket
1
F4
11
GB170-1986
Nut
2
Serial number
Code
Name
Quantity
Material
1
1
1
1
1
1
1
1
1
Figure 7 Structure Diagram of Oil refilling Valve
B. Reasons
The oil refilling valve acts mainly because the diaphragm chamber is not full after leakage occurs. Specifically,
when the piston is pushed in, the diaphragm chamber is empty. If the piston is further pushed in, a vacuum is
formed inside the diagram chamber. Under certain vacuum conditions, the oil refilling valve spool (connecting
rod ball) will make up oil against spring so that the diaphragm chamber is full of hydraulic oil, the diaphragm
withholds equal force on both sides, and its service life is prolonged.
C. Adjustment
For the oil refilling valve, its spring force is mainly adjusted. Under common working conditions (when the inlet
is under positive pressure), the spring force of connecting rod ball should be adjusted at around 100g (f). If the
pump is pushed in, especially under certain negative pressure, the spring force will gradually increase, so as to
avoid diaphragm damage resulting from excessive oil refill.
