A.1.4 Hr Servo Solenoid Valves - Siemens Sinumerik 840D Series Function Manual

A Hydraulics
A.1 Servo solenoid valves
A.1.4 HR servo solenoid valves
General
Features
Graphic symbol in simplified form
O B
P T
Fig. A-17 Directly-controlled HR servo solenoid valve (Rexroth)
A-252
The HR (High Response) series of servo solenoid valves from Bosch
Rexroth offers particularly good dynamic and static characteristics, making it the
ideal addition to the range for highly sophisticated applications.
At the heart of the series is the 4WRREH 6 valve. This is also used as a pilot
valve in type 4WRVE pilot-controlled HR servo solenoid valves.
Both valve stages on pilot-actuated valves operate under position control.
In contrast to the other valves, the HR servo solenoid valve has the following
features:
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Significantly better dynamic response
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More compact dimensions
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A higher hydraulic switching capacity.
The HR valve comprises the following components:
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Flow-force-compensated hydraulic section with wear-resistant steel sleeve
and spring centered control spool
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Double-stroke solenoid with inductive position encoder (LVDT) and
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Integrated electronics (OBE)
HR valves do not have the fail-safe position provided on other servo solenoid
valves. Many applications therefore require external non-return valves,
such as those available as sandwich-plate valves.
12-pin connector
Valve amplifier
Steel sleeve Valve spool
SINUMERIK 840D/SIMODRIVE 611 digital, HLA Module (FBHLA) - 10.03 Edition
Double-stroke solenoid Position encoder
 Siemens AG, 2003. All rights reserved
10.03