Detailed description

The A2FM is a fixed displacement motor featuring an axial piston, bent axis design, specifically engineered to be suitable for hydrostatic drives in both open and closed circuits. Its bent axis structure optimizes power transmission efficiency, reduces internal mechanical wear, and ensures stable operation in different circuit systems, meeting the diverse needs of hydraulic drive applications. This motor is widely applicable to both mobile and industrial scenarios, including construction machinery, agricultural equipment, industrial hydraulic stations, and other equipment requiring reliable hydraulic power, adapting well to harsh mobile working environments and stable industrial operation conditions. The output speed of the A2FM motor depends on the flow capacity of the matching pump and the motor’s own displacement—higher pump flow or smaller motor displacement leads to higher output speed, allowing flexible adaptation to different speed requirements. Its torque increases with the pressure difference between the high and low pressure sides, as well as with increasing displacement, ensuring sufficient power to drive heavy loads stably. A careful selection of the available displacement options allows the motor sizes to be precisely matched to practically every application, enhancing versatility. Additionally, it adopts one-piece pistons with piston rings, which improves sealing performance, reduces internal leakage, and enhances the motor’s durability and operational reliability.

Technical Data

Hydraulic fluid

The A2FM fixed displacement motor is suitable for use with mineral oil.

Viscosity range

We recommend that a viscosity (at operating temperature)for optimum

efficiency and service life purposes of

V_op_t= optimum viscosity 16...36mm²/s

Be chosen, taken the circulation temperature (closed circuit) and tank temperature (open circuit) into account.

Limits of viscosity range

The following values apply extreme cases:

V_min=5mm²/s
short term(t < 3 min) at max. permitted temperature
t_max=115℃

V_max=1600mm²/s
short term (t<3 min) with cold start(P<3MPa,
n≤1000rpm t_min=-40℃)

Note that the maximum hydraulic fluid temperature must not be exceeded locally either (e.g.bearing area).The temperature in the bearing area is-depending on pressure and speed-up to 12 K higher than the average case drain temperature.

Selection diagram

Details regarding the choice of hydraulic fluid

The correct choice of pressure fluid requires knowledge of the operating temperature in relation to the ambient temperature:in a closed circuit the circulation temperature,in an open circuit the tank temperature.

The hydraulic fluid should be selected so that within the operating temperature range,the operating viscosity lies within the optimum range (υ opt) (see shaded section of the selection diagram).We recommend that the highest possible viscosity range should be chosen in each case.

Example:At an ambient temperature of X℃ an operating temperature of 60℃ is set in the circuit . In the optimum operating viscosity range (υ opt; shaded area) this corresponds to the viscosity classes VG 46 or VG68; to be selected: CG 68

Please note : The leakage fluid temperature, which is affected by pressure and rotational speed, is always higher than the circulation temperature or tank temperature. At no point in the system may t-he temperature be higher than 115℃.

Filtration

The finer the filtration, the cleaner the fluid and the longer the service life

of the axial piston unit.

To ensure proper function of the axial piston unit, the hydraulic fluid must have a cleanliness level of least.

20/18/15 according to ISO 4406.

At very high hydraulic fluid temperatures (90℃ to max. 115℃),a cleanliness level of at least.

19/17/14 according to ISO 4406 is required.

Please contact us if these cleanliness levels cannot be achieved.

Operational pressure range

Maximum pressure on port A or B

(pressure data according to DIN 24312)

	Shaft end A,Z	Shaft end B, P
Nominal pressure P_N	40 Mpa	35 Mpa
Peak pressure P_max	45 MPa	40 MPa
summation pressure (A+B)	70 MPa	70 MPa

Please note:at the shaft end Z and P, a nominal pressure of P_N=31. 5MPa (P_max=35MPa) is permitted for the driven shaft end that is subjected to transverse bending (pinions, V-belts) !

Size 56 with shaft end Z:P_N=35MPa, P_max=40MPa

in cases of pulsating loading above 31. 5MPa, we recommend the version with splined shaft A or splined shaft Z(sizes 45)

Direction of flow

Speed rang

No limit to minimum speed n_min. If uniform motion is required,n_min must not be less than 50 rpm.

Shaft seal ring

permissible pressure load

The pressure service life of the shaft seal ring is affected by the speed of the motor and the case drain pressure. The permitted loading with intermittent case drain pressure depends on the rotational speed(see chart). Short-term (t<5 min) pressure spikes of up to 1 Mpa absolute are permitted.

The average permanent case drain pressure must not exceed 0. 3Mpa absolute.

The pressure in the case must be equal to or greater than the external pressure on the shaft seal.

Temperature range

The FKM shaft seal is admissible for a housing temperature range

from -25℃ to +115℃

Table of values (theoretical values, ignoring η_min and η_v; values rounded)

Size				10	12	16	23	28	32	45
Displacement		V_g	mL/r	10.3	12.0	16.0	22.9	28.1	32	45.6
Speed max		n_max	min^-1	8000	8000	8000	6300	6300	6300	5600
Speed max		n_{max limit}¹⁾	min^-1	8800	8800	8800	6900	6900	6900	6200
Flow max.		q_vmax	L/min	82	96	128	144	176	201	255
Torque constants		T_K	Nm/MPa	1.64	1.9	2.5	3.6	4.45	5.09	7.25
Torque at	Δp=35 MPa	T	Nm	57	67	88	126	156	178	254
Torque at	Δp=40 MPa	T	Nm	65	76	100	144	178	204	290
Filling capacity			L	0.17	0.17	0.17	0.20	0.20	0.20	0.33
Mass moment of inertia around output shaft		J	kgm²	0.0004	0.0004	0.0004	0.0012	0.0012	0.0012	0.0024
Mass(approx.)			kg	5.4	5.4	5.4	9.5	9.5	9.5	13.5

Size				56	63	80	90	107	125	160	180
Displacement		V_g	mL/r	56.1	63.0	80.4	90.0	106.7	125.0	160.4	180.0
Speed max		n_max	min^-1	5000	5000	4500	4500	4000	4000	3600	3600
Speed max		n_{max limit}¹⁾	min^-1	5500	5500	5000	5000	4400	4400	4000	4000
Flow max.		q_vmax	L/min	280	315	360	405	427	500	577	648
Torque constants		T_K	Nm/MPa	8.9	10.0	12.7	17.0	19.9	25.4	28.6	31.8
Torque at	Δp=35 MPa	T	Nm	312	350	445	501	595	697	889	1001
Torque at	Δp=40 MPa	T	Nm	356	400	508	572	680	796	1016	1144
Filling capacity			L	0.45	0.45	0.55	0.55	0.8	0.80	1.1	1.1
Mass moment of inertia around output shaft		J	kgm²	0.0042	0.0042	0.0072	0.0072	0.0116	0.0116	0.0220	0.0220
Mass(approx.)			kg	18	18	23	23	32	32	45	45

1) intermittent maximum speed: overspeed at discharge and over-running travel operations,t<5 sec. and Δp<15MPa.

Determining the size

Flow	q_v=(V_g∙n)/(1000∙η_v)	[L/min]	V_g=Displacement per revolution in mL/r Δp=Differential pressure in MPa n=Speed in rpm η_v=Volumetric efficiency η_mh=Mechanical-hydraulic efficiency η_t=Overall efficiency
speed	n=(qv∙1000∙ηv)/Vg	[rpm]
Torque	T=（V_g∙ Δp∙η_mh）/20π	[Nm]
Power	P=(2π∙T∙n)/60000=(q_v∙Δp)/(600∙ηt)	[KW]

Permissible radial and axial loading on the drive shaft

The values given are maximum values and do not apply to continuous operation

Size			10	12	16	23	28	32	45	56
Radial force,max.¹⁾ at distance a (from shaft collar)	F_qmax	N	2350	2750	3700	4300	5400	6100	8150²⁾	9200²⁾
Radial force,max.¹⁾ at distance a (from shaft collar)	a	mm	16	16	16	16	16	16	18	18
Axial force, max.³⁾	＋F_{ax max}	N	320	320	320	500	500	500	630	800
Axial force, max.³⁾	-F_{ax max}	N	320	320	320	500	500	500	630	800
Permissible axial force/MPa operating pressure	±Fax per/MPa	N/MPa	30	30	30	52	52	52	70	87

Size			63	80	90	107	125	160	180
Radial force,max.¹⁾ at distance a (from shaft collar)	F_qmax	N	10300	11500²⁾	12900	13600	15900	18400	20600
Radial force,max.¹⁾ at distance a (from shaft collar)	a	mm	18	20	20	20	20	25	25
Axial force, max.³⁾	＋F_{ax max}	N	800	1000	1000	12500	1250	1600	1600
Axial force, max.³⁾	-F_{ax max}	N	800	1000	1000	12500	1250	1600	1600
Permissible axial force/MPa operating pressure	±Fax per/MPa	N/MPa	87	106	106	129	129	167	167

1) during intermittent operation

2)permissible max.radial force with shaft end Z:Fq max = 6500N

3)max. permissible axial force when stopped or when axial piston unit working in pressureless conditions

4)when stopped or when axial piston unit working in pressureless condition. Higher forces are permitted when under pressure.

Please contact us.

When considering the permissible axial force, the force-transfer direction must be taken into account:

-F_ax_max = increase in service life of bearings

+F_ax_max=reduction in service life of bearings(avoid if at all possible)

Minimum inlet pressure on service line port A(B)

In order to avid damage of the motor a minimum inlet pressure at the inlet zone must be assured.

The minimum inlet pressure is related to the rotational speed of the fixed motor.

Please contact us if these conditions cannot be satisfied.

Fixed Displacement Motor A2F

Detailed description