ISO 5781:2000 pdf download
ISO 5781:2000 pdf download.Hydraulic fluid power – Pressure-reducingvalves, sequence valves, unloading valves,throttle valves and check valves 一 Mounting surfaces.
4.2 The graphic symbols used in Figures 2, 3, 5, 6, 8, 9, 11, 12, 14 and 15 are in conformance with the graphical symbols in ISO 121 9-1.
4.3 The code system used in this International Standard is defined in ISO 5783.
5 Tolerances
5.1 The following values shall be applied to the mounting surface, i.e. the area within the chain thick lines:
surface roughness: Ra 0,8 pm (see ISO 1302);
— surface flatness: 0,01 mm over a distance of 100 mm (see ISO 1101); tolerance on diameters of locating pin holes: Hi 2
5.2 With respect to the point of origin, along the x and v axes, the following tolerances shall be complied with:
— pin holes: ± 0,1 mm
— screw holes: ± 0,1 mm
— main ports: ± 0,2 mm
For the other dimensions, refer to the figures.
6 Dimensions
6.1 Mounting surface dimensions for hydraulic pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves shall be selected from the figures and tables specified in 6.2 to 6.6.
6.2 Mounting surface dimensions for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 4,5 mm maximum diameter (code: 5781-02-01-0-00) are given in Figure 1.
6.3 Mounting surface dimensions for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 7,5 mm maximum diameter (code: 5781-03-04-0-00) are given in Figure 4.
6.4 Mounting surface dimensions for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 14,7 mm maximum diameter (code: 5781-06-07-0-00) are given in Figure 7.
6.5 Mounting surface dimensions for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 23,4 mm maximum diameter (code: 5781-08-10-0-00) are given in Figure 10.
6.6 Mounting surface dimensions for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 32 mm maximum diameter (code: 5781-10-13-0-00) are given in Figure 13.
7 Port marking
7.1 The port symbols to be used for pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves shall be selected from the figures specified in 7.2 to 7.11.
7.2 The symbols for directly-operated pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 4,5 mm maximum diameter (code: 5781-02-01-0-00) are given in Figure 2.
7.3 The symbols for pilot-operated pressure-reducing valves, sequence valves and unloading valves with main ports of 4,5 mm maximum diameter (code: 5781 -02-01-0-00) are given in Figure 3.
7.4 The symbols for directly-operated pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 7,5 mm maximum diameter (code: 5781-03-04-0-00) are given in Figure 5.
7.5 The symbols for pilot-operated pressure-reducing valves, sequence valves and unloading valves with main ports of 7,5 mm maximum diameter (code: 5781 -03-04-0-00) are given in Figure 6.
7.6 The symbols for directly-operated pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 14,7mm maximum diameter (code: 5781-06-07-0-00) are given in Figure 8.
7.7 The symbols for pilot-operated pressure-reducing valves, sequence valves and unloading valves with main ports of 14,7 mm maximum diameter (code: 5781 -06-07-0-00) are given in Figure 9.
7.8 The symbols for directly-operated pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 23,4 mm maximum diameter (code: 5781-08-10-0-00) are given in Figure 11.
7.9 The symbols for pilot-operated pressure-reducing valves, sequence valves and unloading valves with main ports of 23,4 mm maximum diameter (code: 5781 -08-10-0-00) are given in Figure 12.
7.10 The symbols for directly-operated pressure-reducing valves, sequence valves, unloading valves, throttle valves and check valves with main ports of 32 mm maximum diameter (code: 5781-10-13-0-00) are given in Figure 14.
7.11 The symbols for pilot-operated pressure-reducing valves, sequence valves and unloading valves with main ports of 32 mm maximum diameter (code: 5781-10-13-0-00) are given in Figure 15.
7.12 The direction A to B should not be used in new designs.
8 Modular stack valves
For modular stack valves, the mounting surfaces and port markings defined in ISO 4401 shall be used.
9Rated pressure
For an indication of the maximum limit of the rated pressure, see paragraph 1 of Figures 1,4,7,10 and 13.
10 ldentification statement (Reference to this International Standard)
lt is strongly recommended to manufacturers who have chosen to conform to this International Standard that thefollowing statement be used in test reports,catalogues and sales literature:
“Mounting surface dimensions of pressure-reducing valves, sequence valves, unloading valves, throttle valves andcheck valves conform to ISO 5781:2000，Hydraulic fluid power — Pressure-reducing valves，sequence valves,unloading valves, throttle valves and check valves – Mounting surfaces.”
The supplier shall establish the maximum rated pressure for subplates and manifold blocks.
The minimum thread depth is 1.5 times the screw diameter, D. The full thread depth recommended is 2D +6 mm, tofacilitate interchangeability of valves and reduce the number of fixing screw lengths. The recommended engagement of fixingscrew thread for ferrous mountings is 1,25D.
