for motor/pump service 
Series QXM 


Reference: 100-P-000063-E-04 

Issue: 07.11 1/16 


s 
Page 

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1 General 
3 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

1.1 
Product description 3 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.2 
Advantages 3 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
1.3 Application 
3 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

2 Technical data 
3 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

2.1 
General 3 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
2.2 
Pressure range 1 4 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
2.3 
Pressure range 2 5 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
2.4 Pressure range 3 
6 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

3 Performance graphs 
7 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

3.1 
Pressure range 1 7 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
3.2 
Pressure range 2 8 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
3.3 
Pressure range 3 9 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
3.4 Noise level (Lp) 
10 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

4 Dimensions 
10 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

4.1 
Pressure range 1 11 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.2 
Pressure range 2 11 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.3 
Pressure range 3 11 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.4 
Ordering details 12 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.5 
Ordering example 12 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.6 
Standard configuration 12 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.7 
Special features 12 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
4.8 Direction of rotation 
12 
5 Fluid cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 
6 Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 
7 Fluid cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 
8 Operational reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

9 Accessories 
14 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

9.1 
Pipe flanges - high pressure type 14 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
9.2 
Low pressure type 14 
. . . . . . . . . . . . . . . . . . . . . . . . . . . 
9.3 Bolt-on valves - SAE J518 code 61 / ISO 6162-1 pattern 
15 
100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 




1.1 Product description 
The QXM drive unit can be used in open- and closed-loop 
hydrostatic drives, and can operate both as a pump and as 
a motor. 

This flexibility offers possibilities for various applications, 
one example being the raising and lowering of loads. The 
QXM works as a pump to lift the load and recovers energy 
when the load is being lowered. 

Used as a fully bi-directional pump/motor (four-quadrant 
operation), the unit controls a complete motion cycle of a 
cylinder. Fast acceleration/deceleration sequences can be 
achieved. 
The unit is based on the well-known QX internal gear pump, 
which is distinguished by its very low noise levels and almost 
imperceptible pressure pulsations. The large number 
of closely spaced sizes ensures that the right size is always 
available for every application. 

2 Technical data 

2.1 General 
1.2 Advantages 
. 
Very low noise levels 
. 
Negligible pressure pulsations 
. 
400 bar maximum pressure 
. 
Long service life 
. 
Suitable for special fluids such as HFB, HFC, HFD 
and bio-degradables 
. 
Suitable for variable-speed operation 
. 
2- and 4-quadrant operation is possible 
. 
Optimised flow path cross-sections and special gear 
profile give low susceptibility to cavitation 
1.3 Application 
. 
Injection molding machines 
. 
Hydraulic presses 
. 
Flight simulators 
. 
Wind-power plants 
. 
Lift/elevator drives 
. 
Winches 
Characteristics Description, value, unit 
Installation attitude unrestricted 
Mounting method (standard) oval 2-hole flange to ISO 3019/1 (SAE): QXM 3-6 
oval 2-hole flange to ISO 3019/2 (metric) QXM 2+8 
Direction of rotation unrestricted 
Drive method in-line, by a flexible coupling 
Hydraulic fluid HLP mineral oils to DIN 51524, Part 2 
HFB, HFD and HFC fluids to VDMA 24317 
other fluids - contact Bucher Hydraulics 
Min. fluid cleanliness level ISO 4406 class 20/18/15, or NAS 1638 class 9 
Operating viscosity 
Starting viscosity 
10 to 100 mm2/s 
10 to 300 mm2/s (higher values, contact Bucher Hydraulics) 
Hydraulic fluid temperature HLP mineral oil - 80C max. 
HFB, HFD and HFC 50C max. 
Max. pressure at drain port 1.5 bar absolute (higher values, contact Bucher Hydraulics) 
Accumulated pressure restriction Port P1 + Port P2 . 
continuous-/intermittent pressure 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Pressure range 1 
These operating data are valid for mineral oils with 42 mm2/s 

Type Displacement 
minimum Motor 
Speed 
[min-1] 5) 
maximum Speed 
[min-1] 3) 
Operating pressure 
on outlet side 
[bar] 
Torque 2) 
nominal effective 
Operating pressure 
on outlet side 
Pump Motor conti- intermit- 
[cm3/U] [cm3/U] ... 50% ... 100% operat. 4) operating nous tend 1) [Nm] 
QXM21-010 
QXM21-012 
QXM21-016 
010 
012 
016 
10 
12,6 
15,6 
1000 2500 
4000 
3600 
3200 
5500 
160 
125 
100 
210 
160 
125 
25 
QXM31-020 
QXM31-025 
QXM31-032 
020 
025 
032 
20,3 
25,1 
32,3 
800 2000 
3200 
3000 
2700 
5000 
160 
125 
100 
210 
160 
125 
50 
QXM41-040 
QXM41-050 
QXM41-063 
040 
050 
063 
39,2 
50,5 
63,5 
600 1500 
2700 
2350 
2050 
4600 
160 
125 
100 
210 
160 
125 
100 
QXM51-080 
QXM51-100 
QXM51-125 
080 
100 
125 
80,1 
100,9 
124,6 
600 1500 
2050 
1900 
1620 
4000 
160 
125 
100 
210 
160 
125 
200 
QXM61-160 
QXM61-200 
QXM61-250 
160 
200 
250 
162,7 
200,9 
248,8 
600 1500 
1500 
1350 
1200 
3200 
160 
125 
100 
210 
160 
125 
400 
QXM81-315 
QXM81-400 
QXM81-500 
315 
400 
500 
326 
402,6 
498,5 
600 1200 
1200 
1100 
1000 
3000 
160 
125 
100 
210 
160 
125 
800 

1) Intermittent pressure for max. 20 sec/min but not more than 10% of the duty cycle 
2) Theoretical value at the maximum permitted continuous pressure. For starting torques, see section 3. 
3) For higher speed contact us 
4) Minimum inlet pressure 1 bar absolute 

5) Recommended speed. For less speed the pressure must be reducing ( linear rate). 
For customized working cycle contact Bucher Hydraulics. 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


2.3 2.3 
These operating data are valid for mineral oils with 42 mm2/s 


Type Displacement 
minimum Motor 
Speed 
[min-1] 5) 
maximum Speed 
[min-1] 3) 
Operating pressure 
on outlet side 
[bar] 
Torque 2) 
nominal effective 
Operating pressure 
on outlet side 
Pump Motor conti- intermit- 
[cm3/U] [cm3/U] ... 50% ... 100% operat. 4) operating nous tend 1) [Nm] 
QXM22-010 
QXM22-012 
QXM22-016 
005 
006 
008 
5,1 
6,3 
8,0 
1650 3000 3250 6000 210 250 
17 
21 
26,5 
QXM32-010 
QXM32-012 
QXM32-016 
010 
012 
016 
10,0 
12,6 
15,6 
1400 2500 3050 5500 210 250 
33,5 
42 
52 
QXM42-020 
QXM42-025 
QXM42-032 
020 
025 
032 
20,3 
25,1 
32,3 
1000 1800 2900 5000 210 250 
68 
84 
108 
QXM52-040 
QXM52-050 
QXM52-063 
040 
050 
063 
39,2 
50,5 
63,5 
1000 1800 2500 4500 210 250 
131 
169 
212 
QXM62-080 
QXM62-100 
QXM62-125 
080 
100 
125 
80,1 
100,9 
124,6 
1000 1800 
2250 
2050 
1800 
4000 210 250 
268 
337 
416 
QXM82-160 
QXM82-200 
QXM82-250 
160 
200 
250 
162,7 
200,9 
248,8 
1000 1800 
1600 
1500 
1350 
3500 210 250 
544 
671 
832 

1) Intermittent pressure for max. 20 sec/min but not more than 10% of the duty cycle 
2) Theoretical value at the maximum permitted continuous pressure. For starting torques, see section 3. 
3) For higher speed contact us 
4) Minimum inlet pressure 1 bar absolute 

5) Recommended speed. For less speed the pressure must be reducing ( linear rate). 
For customized working cycle contact Bucher Hydraulics. 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Pressure range 3 
These operating data are valid for mineral oils with 42 mm2/s 

Type Displacement 
minimum Motor 
Speed 
[min-1] 5) 
maximum Speed 
[min-1] 3) 
Operating pressure 
on outlet side 
[bar] 
Torque 2) 
nominal effective 
Operating pressure 
on outlet side 
Pump Motor conti- intermit- 
[cm3/U] [cm3/U] ... 50% ... 100% operat. 4) operating nous tend 1) [Nm] 
QXM23-005 
QXM23-006 
QXM23-008 
005 
006 
008 
5,1 
6,3 
8,0 
1200 2500 3250 6000 320 400 
26 
32 
41 
QXM33-010 
QXM33-012 
QXM33-016 
010 
012 
016 
10,0 
12,6 
15,6 
1000 2000 3050 5500 320 400 
51 
64 
80 
QXM43-020 
QXM43-025 
QXM43-032 
020 
025 
032 
20,3 
25,1 
32,3 
750 1500 2900 5000 320 400 
103 
128 
164 
QXM53-040 
QXM53-050 
QXM53-063 
040 
050 
063 
39,2 
50,5 
63,5 
750 1500 2500 4500 320 400 
200 
257 
323 
QXM63-080 
QXM63-100 
QXM63-125 
080 
100 
125 
80,1 
100,9 
124,6 
750 1500 
2250 
2050 
1800 
4000 320 400 
408 
514 
635 
QXM83-160 
QXM83-200 
QXM83-250 
160 
200 
250 
162,7 
200,9 
248,8 
750 1500 
1600 
1500 
1350 
3500 320 400 
828 
1023 
1267 

1) Intermittent pressure for max. 20 sec/min but not more than 10% of the duty cycle 
2) Theoretical value at the maximum permitted continuous pressure. For starting torques, see section 3. 
3) For higher speed contact us 
4) Minimum inlet pressure 1 bar absolute 

5) Recommended speed. For less speed the pressure must be reducing ( linear rate). 
For customized working cycle contact Bucher Hydraulics. 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 




3.1 Pressure range 1 
3.1.1 Volumetric efficiency 
Measured with n = 1450 min-1 
Viscosity 42 mm2/s 

h [%]

 80 
90 
100 
21 
81 
61 
51 
41 
31 
95 
85 QXM 
p [bar]

50100 125 160 210

3.1.3 Starting torque 
M [N]

m
40 


30 

010 

20 

10 

0 

QXM 21 
016 012 

0 25 50 75 100 125 150 175 200 p [bar] 

M [Nm] 

80 

60 
020 
40 


20 

0 
0 25 50 75 100 125 150 175 200 p [bar] 

QXM 31 
032 
025 

M [Nm] 
120 
040 

100 
80 
60 
40 

20 
0 
0 25 50 75 100 125 150 175 200 p [bar] 


050QXM 41 063 

3.1.4 Maximum pressure accumulation at P1 + P2
p [bar] 
180 

140 

100 
60 
20 
0 1000 2000 3000 4000 5000 6000n [min-1] 


3.1.2 Hydro-mechanical efficiency 
h [%] 

31 
81 
90 
100 
21 
41 
51 
61 
85 
95 
QXM 
80

50 100 125 160 210p [bar] 

M [Nm] 

080 

300 
225 
150 
75 

QXM 51 
125 
100 

0 

0 25 50 75 100 125 150 175 200 p [bar] 
M [Nm] 
600 
450 
300 
150 

0 

250 
200 
QXM 61 

0 25 50 75 100 125 150 175 200 p [bar] 
M [Nm] 

300 
150 
450 
600 
750 
900 
315400 
500 
0 
QXM 81 
0 25 50 75 100 125 150 175 200 p [bar] 


= Dependent on frame size (see 2.2) 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Pressure range 2 
3.2.1 Volumetric efficiency 
Measured with viscosity 42 mm2/s, speed 1450 min-1 

Solid line = continous pressure / dashed line = max. intermittent pressure 
h [%] 

70 
80 
90 
100 
82 
62 
52 
42 
32 
22 
QXM 
0 50 100 150 200 250 p [bar] 

3.2.3 Starting torque 
M [Nm] 

QXM 32 


40 
30 
008 


20 
006 
005 
10 


0 
0 50 100 150 200 250 p [bar] 

QXM 22 

M [N]

m
60 


016 
40 
012 


010 
20 


0 
0 50 100 150 200 250 p [bar] 

M [Nm] 


120 

QXM 42 

032 

100 
80 

025 
020 

60 

40 
20 
0 


0 50 100 150 200 250 p [bar] 

3.2.4 Maximum pressure accumulation at P1 + P2
p [bar] 
250 
200 
150 
100 
50 


QXM 52 


QXM 62 


QXM 82 


3.2.2 Hydro-mechanical efficiency 
h [%] 
100 
90 

80 

70 

QXM 

0 50 100 150 200 

M [N]

m
200 


150 
100 
50 
0 

0 50 100 150 200 
M [Nm] 
400 
300 
200 
100 
0 
0 

50 100 150 200 
M [Nm] 
800 
600 
400 
200 
0 
0 
00 50 100 150 200 


82 
62 
52 
42 
32 
22 

250 p [bar] 

063 
050 
040 

250 p [bar] 

125 
100 
080 

250 

p [bar] 

250 
200 
160 

250 p [bar] 


= Dependent on frame size (see 2.3)

1000 2000 3000 4000 5000 6000 n [min-1] 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Pressure range 3 
3.3.1 Volumetric efficiency 
Measured with viscosity 42 mm2/s, speed 1450 min-1, 

Solid line = continous pressure / dashed line = max. intermittend pressure 
h [%] 

100 

QXM 

83

90 

63 
53 
43 

80 

33 

23 

70 
0 50 100 150 200 250 300 350 400 p [bar] 

3.3.3 Starting torque 
M [Nm] 


40 

QXM 23 

008 
006

30 
005 


20 
10 
0 

0 100 200 300 400 p [bar] 
M [N]

m


100 
80 

QXM 33 

016 
012 

60 

010 

40 
20 
0 


0 100 200 300 400 p [bar] 
M [Nm] 


180 

QXM 43 

032 

140 

025 
100 

020 

60 

20 
0 


0 100 200 300 400 p [bar] 

3.3.4 Maximum pressure accumulation at P1 + P2
p [bar] 
350 
300 
250 
200 
150 
100 
50 


0 1000 2000 3000 4000 5000 6000 n [min-1] 


3.3.2 Hydro-mechanical efficiency 
h [%] 

100 
90 
80 
70 
83 
63 
53 
43 
33 
23 
QXM 
QXM 63 


0 50 100 150 200 250 300 350 400 p [bar] 

M [Nm] 
400 

QXM 53 

063 
300 
050 
200 

040 
100 
0 

0 100 200 300 400 p [bar] 

M [Nm] 
800 

125 
600 
100 
400 

080 

200 
0 
0 100 200 300 400 p [bar] 
M [Nm] 


1400 

QXM 83 

250 

1200 

200

1000 

160

800 

600 
400 
200 
0 

0 100 200 300 400 p [bar] 


= Dependent on frame size (see 2.4) 

100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Noise level (Lp) 
Measured to DIN 45635, Part 26, in Stuttgart University’s low-echo noise 
Measurement chamber; 
Measurement distance 1 m; speed n = 1500 rpm; viscosity = 42 mm2/s 

LP [dB(A)] Q [l/min] 

80 
720 
360 
70 180 
92 
46 
60 
23 
11,5 
6,1 
50 
40 
40 
p [bar] 
10 
20 
120 
30 
60 
200 
50 
100 
280 320 
70 90 
140 180 
110 1 
2 
3 
Pressure range 

125 
210 
Dimensions 

Frame size 2 3 4 5 6 8 
Pressure range 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 
Service ports to SAE 
J518 1) P1, P2 
G1/2 3) 
thread 
G 3/4" 3) 
thread 
1" 1 1/4" 1 1/2" 2" 
Drain port to 
DIN 3852 Teil 2 
Part 2 
PL G1/4" G1/4" G1/4" G1/4" G 3/8" G1/2" 
Mounting: oval 
2-hole flange to ISO 
3019/1 
(SAE - size 3-6) 
ISO 3019/2 
(Metr. - sizes 2+8) 
A 118 132 170 212 267 330 
B(SAE) - 106 146 181 229 - 
B(Metr.) 100 109 140 180 224 280 
C 9 11 14 18 22 26 
N(SAE) - 82,55 - 0,05 101,6 - 0,05 127 - 0,05 152,4 - 0,05 - 
N(Metr.) 63 h8 80 h8 100 - h8 125 h8 160 - h8 200 h8 
O 8,5 8,5 10,5 12,5 16,5 20 
V 6 6 7 7 7 9 
Shaft end: 
parallel, to 
ISO/R775 2) 
D 20 j6 25 j6 32 j6 40 j6 50 j6 63 j6 
E 36 42 58 82 82 105 
F 6 8 10 12 14 18 
G 22,5 28 35 43 53,5 67 
I 45 50 68 92 92 117 
Housing 
K 37,5 44 52,5 60,5 74 90 
L 140 122 157 166 146 191 204 178 234 244 212 282 289 249 339 364 314 429 
M - 55 90 - 69,5 114 - 87 143 - 102 172 - 119 209 - 151 266 
T 86 107 133 177 214 220 273 275 
Z 50 60 62,5 78 97,5 125 
Weight kg 5 5 6,5 10 9,5 12,5 18 17 22 33 31 40 64 60 76 130 120 160 

1) For SAE J518 code 61 bzw. ISO6162-1 pipe flange dimensions see section 9 
2) For other shaft ends, contact Bucher Hydraulics 
3) Threaded ports to DIN 3852 Part 2 
10/16 100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


4.1 4.1 
L 


I K 
E P1, P2 
NGD 
V 
O 
T 
C 
A 
F 
B 
Z Z 
Port P2 Port P1 
External drain port PL 
4.2 Pressure range 2 
L 

I K M 
E 
N 
P2 
GD 
V 
O 
TA 
C 
F 
B 
Z Z 
P1 
Port P2 
Port P1 
External drain port PL 
4.3 Pressure range 3 
I 
L 
K M 
E 
T 
NGD 
V 
O 
C 
A 
Z Z 
B 
F 
P2 
External drain port PL 
Port P1 + P2 
P1 
100-P-000063-E-04/ 07.11 
Internal Gear Unit QXM 


Ordering details 
5 3QX M 
- 


N0 4 0 ** * 
Internal gear unit 
QXM 

Frame size 
2 / 3 / 4 / 5 / 6 / 8 

Pressure range 
1 / 2 / 3 

Geom. Displ./Consump. in cm3/rev 005 - 500 

Direction of rotation, unrestricted = N (see section 4.8) 

Variants / special features (to be inserted by the factory, see section 4.7 for a selection) 


4.5 Ordering example 
Required: internal gear drive unit QXM 
Displ./Consump.: 40 cm3/rev 
Continuous pressure: 300 bar 
For use with mineral oil: HLP 
Ordering code: QXM 53-040 N 

4.6 Standard configuration 
. 
Direction of rotation - unrestricted 
. 
2-hole mounting flange to ISO 3019/1; Frame size QXV 3-6 
2-hole mounting flange to ISO 3019/2; Frame size QXV 2+8 
. 
Nitrile seals 
. 
Cylindrical shaft end to ISO R775 
. 
Separate drain port in rear cover of the drive unit 
. 
Ports P1 + P2 both the same size 
. 
Compression proof shaft seal 
4.7 Special features 
09 = Viton seals 
130 = 2-quadrant operation, service port dimensions as per QX pumps 

2-hole mounting flange to ISO 3019/2 (metric) 
For other special features, contact Bucher 
Commissioning see Operating Instructions 100-I-000014 

4.8 Direction of rotation 
Direction of rotation: right 
(clockwise, viewed from the shaft end) = oil flows from P1 to P2 

Direction of rotation: left 
(counterclockwise , viewed from the shaft end) = oil flows from P2 to P1 

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Internal Gear Unit QXM 




QXM internal gear units require a fluid with a minimum 
cleanliness level of NAS 1638, Class 9 or ISO 4406, code 
20/18/15. 
HLP hydraulic oils to DIN 51524, Part 2, can be used without 
any special restriction as long as they remain within the specified 
temperature and viscosity ranges. HFC fire-resistant 
fluids to DIN 51502 can be used. Note that all fire-resistant 
fluids require special versions of the pumps or motors and 
must be approved by Bucher Hydraulics. We recommend 
the use of fluids that contain anti-wear additives for mixed- 
friction operating conditions. Fluids without appropriate additives 
can reduce the service life of pumps and motors. The 
user is responsible for maintaining, and regularly checking, 
the fluid quality. Bucher Hydraulics recommends a load capacity 
of > 30 N/mm2 to Brugger DIN 51347-2. 

6 Note 

This catalogue is intended for users with specialist knowledge. 
The user must check the suitability of the equipment 
described herein in order to ensure that all of the conditions 
necessary for the safety and proper functioning of the system 
are fulfilled. If you have any doubts or questions concerning 
the use of these pumps, please consult Bucher Hydraulics. 


7 Fluid cleanliness 

Cleanliness class (RK) as per ISO 4406 and 
NAS 1638 

8 Operational reliability 

To ensure a reliable operation and a long service life of the 
QXM internal gear units, a maintenance schedule must be 
prepared for the power unit, machine or system. The maintenance 
schedule must make sure that the provided or permissible 
operating conditions of the QXM internal gear units 
are adhered to over the period of use. 
In particular, compliance with the following operating parameters 
must be ensured: 
. The required oil cleanliness 
. The operating temperature range 
. The fluid level 
Moreover, the QXM internal gear units and the system must 
be inspected at regular intervals for changes in the following 
parameters: 
. Vibration 
. Noise 
. Differential temperature of internal gear unit . fluid in the

 tank 
. Foaming in the tank 
. Freedom from leakage 
Changes in these parameters indicate wear of components 

(e.g. drive motor, coupling, internal gear unit, etc.). The 
cause must be immediately pinpointed and eliminated. 
To provide high operational reliability of the QXM internal 
gear unit in the machine or system, we recommend continuous, 
automatic checks of the above parameters and an automatic 
shutdown in the case of changes that exceed the 
usual fluctuations within the provided operating range. 
Code 
ISO 4406 
Dirt particle number / 100 ml 
 4 µm  6 µm  14 µm NAS 1638 
23/21/18 8000000 2000000 250000 12 
22/20/18 4000000 1000000 250000 - 
22/20/17 4000000 1000000 130000 11 
22/20/16 4000000 1000000 64000 - 
21/19/16 2000000 500000 64000 10 
20/18/15 1000000 250000 32000 9 
19/17/14 500000 1300000 16000 8 
18/16/13 250000 64000 8000 7 
17/15/12 130000 32000 4000 6 
16/14/12 64000 16000 4000 - 
16/14/11 64000 16000 2000 5 
15/13/10 32000 8000 1000 4 
14/12/9 16000 4000 500 3 
13/11/8 8000 2000 250 2 

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Internal Gear Unit QXM 




9.1 Pipe flanges - high pressure type 
- Max. operating pressure 420 bar 
- Flange size SAE J518 code 61 / ISO 6162-1 


Threaded pipe flanges are spot-faced for DIN 2353 pipe fitings 
Material: ST37 / For Viton seals, contact Bucher Hydraulics 

Orderingnumber 
Ordering 
code 
Size DØ E F H L R X Y Viton seal 
90 Shore 
’A’ 
Retaining screws 
DIN912-12.9 / 
Torque Nm 
037000 RF 01-R08 G 1/2" 12,5 16 27 13 54 23 17,5 38 20,24x2,62 M8x30 30 
037010 RF 02-R10 G 3/4" 20 18 30 12 65 26 22,2 47,6 26,65x2,62 M10x30 60 
037020 RF 03-R11 G 1" 25 20 34 13 70 29 26,2 52,4 32,99x2,62 M10x35 60 
037030 RF 04-R12 G 1 1/4" 32 22 38 14 80 36 30,2 58,6 40,86x3,53 M10x40 60 
037040 RF 05-R13 G 1 1/2" 38 24 41 19 94 41 35,7 70 44,04x3,53 M12x45 120 
037050 RF 06-R14 G 2" 50 26 45 20 102 48 42,9 77,8 59,92x3,53 M12x50 120 
055470* RF 07-R16 G 2 1/2" * 63 30 50 18 114 57 50,8 89 72,62x3,53 M12x45 120 

* At RF07 only to 210 bar be allowed 
9.2 Low pressure type 
- Max. operating pressure 16 bar 
- Flange size SAE J518 code 61 / ISO 6162-1 

Material: ST37 / For Viton seals, contact Bucher Hydraulics 


Ordering 
number 
Ordering 
code 
SAE 
flange 
Size 
D K F H L R X Y Viton seal 
90 Shore ’A’ 
Retaining screws 
DIN 912-8.8 
Torque Nm 
pipe 1) 
O/dia. 
approx. 
062450 RN 07-S 2 1/2" 63 75 35 14 120 57 51 89 69,44x3,53 M12 x 30 70 75 
063880 RN 08-S 3" 76 88 140,5 68 62 106,5 85,32x3,53 M16 x 40 180 88 
063890 RN 09-S 3 1/2" 89 100 40 19 158,5 73 70 120,3 98,02x3,53 M16 x 40 180 100 
063900 RN 10-S 4" 103 115 168 79 78 130 110,72x3,53 M16 x 40 180 115 

1) We recommend the use of seamless precision steel tube to DIN 2391 with-wallthick. max 6 mm 

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Internal Gear Unit QXM 


9.3 9.3 
Pressure relief Pressure relief 
solenoid control 
Pressure relief 
proportional solenoid control 
Ordering details A DF / A DHS 
G 
S 
G A DA / ASDM S 
G A DPS 
G 
Symbols P T 
M 
Z 
P T 
M 
Z 
P T 
M 
Z 
Unloading valve 
Accomulator charging allve 
Ordering details 
A AF S 
G A SFS 
G 
Symbols P T 
M 
Z 
S = For pipe flange SAE 
J518 code 61 pattern 
(all size) 

G = With threaded port, G 1" 
(size QX2, 3) 

For other informations on Bolt-on valves see data sheet 100-P-000119 

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Internal Gear Unit QXM 




 2011 by Bucher Hydraulics GmbH, D-79771 Klettgau 
All rights reserved. 
Data is provided for the purpose of product description only, and must not be construed as warranted characteristics in the legal sense. 
The information does not relieve users from the duty of conducting their own evaluations and tests. Because the products are subject 
to continual improvement, we reserve the right to amend the product specifications contained in this catalogue. 

Classification: 420.245. 200 

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Internal Gear Unit QXM