ILLUSTRATED S O U RCEBOOK of MECHANICAL C O M P O N E N T S
SECTION 25
Types of Valves Used in Hydraulic Transmissions
25-2
8 Ways to Make a Poppet Valve
25-4
Weirs Replace Gate Valves
25-6
Siphon Serves as Regulating Valve
25-9
Triple-Duty Valve
25-1 1
Flow Regulator Valve
25-13
Fuel Injection Systems-Secondary Problems
25-14
25-2
Types of Valves Used
in Hydraulic Transmissions
Fig. I-Schematic diagram of rotary reversing valve. Oilwoys
in an oscillating cylindrical plug register roith ports rvhich
connect both the main oil line from the pump and the dis-
charge tine to the reservoir with either end of the operating
cylinder. When oil is directed from the pump to one end of
the operating cylinder, oil in the other end of the cylinder is
discharged through the reversing value to the reservoir. One
position of the reversing valve shown.
PUMP
Fig. 3 - Spring-loaded relief calve. This valve is placed in the
piriirp discharge line to permit oil to escape from the line to the
reservoir when the anioimt of nil delivered by a constant-dis-
charge picnip is more than is needed. High pressure over-
comes the compression of the spring. lifts the valve from irs
seat, and by-passes the oil iiirtil the pressure drops below the
compression adjustment of the spring.
MAIN OIL LINE
-FROM
PUMP
Valves are the nerve center of hydraulic circuits.
In machine tools, they provide reversal of mo-
tion, dwell and throttling action, sequence con.
trol, and relief of oil pressure. Some of the corn.
inon forms of these valves are illustrated. Data
and illustrations supplied from Socony-Vacuum
Oil Company publication ”Hydraulic Systems.”
TO CYLINDER h3 2
SPOOL
I
TO CYLINOER
NO 1
FROM PUMP
Fig. 2-Sequence controt valve. Some machines are designed
so that one series of motions mttst be completed before
another series can start. This type valve prevents the flow of
oil IO No. 2 operating cylinder until the motion in No. 1
cylinder has been completed. Both ends of the freely floating
spool