Bosch Rexroth Corp., RE-A 91610/12.2015
10 A6VM series 71 | Axial piston variable motor
HP – Proportional hydraulic control
HP – Proportional hydraulic control
The proportional hydraulic control provides infinite adjust-
ment of the displacement. The control is proportional to 
the pilot pressure applied to port X.
HP1, HP2 positive control
▶ Beginning of control at Vg min (minimum torque, maxi-
mum permissible speed at minimum pilot pressure)
▶ End of control at Vg max (maximum torque, minimum 
speed at maximum pilot pressure)
HP5, HP6 negative control
▶ Beginning of control at Vg max (maximum torque, mini-
mum speed at minimum pilot pressure)
▶ End of control at Vg min (minimum torque, maximum 
permissible speed at maximum pilot pressure)
Note
▶ Maximum permissible pilot pressure: pSt=1450psi (100bar)
▶ The control oil is internally taken from the high pressure 
side of the motor (Aor B). For reliable control, an oper-
ating pressure of at least 435psi (30bar) is required in 
A(B). If a control operation is performed at an operat-
ing pressure <435psi (30bar), an auxiliary pressure of 
at least 435psi (30bar) must be applied at port Gvia 
an external check valve. For lower pressures, please 
contact us. 
Please note that pressures up to 7250psi (500bar) can 
occur at port G.
▶ Please state the desired beginning of control in plain text 
when ordering, e. g.: beginning of control at 145psi (10bar).
▶ The beginning of control and the HP characteristic curve 
are influenced by the case pressure. An increase in case 
pressure causes an increase in the beginning of control 
(see page 6) and thus a parallel displacement of the 
characteristic.
▶ A leakage flow of maximum 0.08gpm (0.3l/min) can 
escape at port Xdue to internal leakage (operating pres-
sure > pilot pressure). The control is to be suitably 
configured to avoid an independent build-up of pilot 
pressure.
Response time damping
The response time damping is influencing the stroke char-
acteristics of the motor and thus the reaction speed of the 
machine.
Standard with Size 60 to 215
HP without damping.
HP.D with throttle pin on both sides, symmetrical (as to 
table)
Option with Size 60 to 215
HP with throttle pin on both sides, symmetrical (as to 
table)
▼ Overview Throttle Pins
Size 60 85 115 150 170 215
Groove 
size 
[inch] 0.018 0.018 0.022 0.022 0.022 0.026
[mm] 0.45 0.45 0.55 0.55 0.55 0.65
HP1, HP5 pilot pressure increase ΔpSt = 145psi (10bar)
HP1 positive control
A pilot pressure increase of 145psi (10bar) at port X
results in an increase in displacement from Vg min to Vg max.
HP5 negative control
A pilot pressure increase of 145psi (10bar) at port X
results in a decrease in displacement from 
Vg max
 
to
 
Vg min.
▶ Beginning of control, setting range 30 to 290psi (2 to 
20bar)
▶ Standard setting: 
Beginning of control at 45psi (3bar) (end of control at 
190psi (13bar))
▼ Characteristic curve
0 0.2 0.4 0.6 0.8 1.0
Vg min Vg max
Vg/ Vg max
HP5 HP1
510 (35)
435 (30)
365 (25)
290 (20)
220 (15)
175 (12)
145 (10)
75 (5)
30 (2)
Beginning of control 
setting range
Displacement
Pilot pressure pSt [psi (bar)]
Pilot 
pressure 
increase