AA2FO23/61R-VBD55

Manufacturer: Bosch Rexroth

Material #: R902156091

Model : AA2FO23/61R-VBD55

***Disclaimer: The following summary contains information gathered from various sources such as product descriptions, technical specifications and catalogs. While efforts have been made to provide accurate details, inaccuracies may occur. It is advised to verify all information by contacting Bosch Rexroth directly.***
The Bosch Rexroth AA2FO23/61R-VBD55 (R902156091) is a high-performance axial piston pump designed for demanding applications requiring a robust and efficient hydraulic power source. This pump is characterized by its bent-axis design, contributing to its very high total efficiency and high power density, ensuring reliable operation and a long service life. The AA2FO23/61R-VBD55 is engineered to handle nominal pressures up to 250 bar with a maximum pressure capacity of up to 315 bar, making it suitable for open circuit systems in a wide range of hydraulic functions. This model is specifically tailored for the US market with an SAE version, ensuring compatibility with standard American equipment interfaces. The pump's large variety of available nominal sizes allows for precise adjustment to specific application requirements, enhancing performance and reducing energy consumption. Additionally, there is an option to include long-life bearings particularly for this nominal size, which further extends the service life of the pump under harsh operating conditions. The Bosch Rexroth AA2FO23/61R-VBD55 is ideal for use in mobile and industrial applications where reliability and efficiency are paramount. Its robust construction and design make it well-suited to function in environments that demand consistent high-pressure hydraulic power. Whether it's in construction machinery, manufacturing equipment, or other heavy-duty hydraulic systems, this pump promises to deliver exceptional performance that meets the stringent requirements of various applications.

$3,113.00 USD

More are expected on April 30, 2025

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Status: This product is temporarily out of stock.

Qty: Delivered as early as April 30, 2025 when ordered in

This product is eligible for factory repair.

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Robust pump with long service life Very high total efficiency High power density Large variety of available nominal sizes allows exact adjustment to the application Optional with long-life bearings for the nominal size 250 Bent-axis design

Table of values

Size				10	12	16	23	28	32	45	56	63	80	90	107	125	160	180	250
Displacement geometric, per revolution		Vg	cm³	10.3	12	16	22.9	28.1	32	45.6	56.1	63	80.4	90	106.7	125	160.4	180	250
Nominal pressure		pnom	bar	400	400	400	400	400	400	400	400	400	400	400	400	400	400	400	350
Maximum pressure		pmax	bar	450	450	450	450	450	450	450	450	450	450	450	450	450	450	450	400
Maximum speed		nnom 1)	rpm	3150	3150	3150	2500	2500	2500	2240	2000	2000	1800	1800	1600	1600	1450	1450	1500
Maximum speed		nmax 2)	rpm	6000	6000	6000	4750	4750	4750	4250	3750	3750	3350	3350	3000	3000	2650	2650	1800
Flow	at nnom	qV	l/min	32	38	50	57	70	80	102	112	126	145	162	171	200	233	261	375
Power	at nnom and pnom	P	kW	22	25	34	38	47	53	68	75	84	96	108	114	133	155	174	219
Torque 3)	at pnom	M	Nm	66	76	102	146	179	204	290	357	401	512	573	679	796	1021	1146	1393
Rotary stiffness		c	kNm/rad	0.92	1.25	1.59	2.56	2.93	3.12	4.18	5.94	6.25	8.73	9.14	11.2	11.9	17.4	18.2	73.1
Moment of inertia for rotary group		JTW	kg·m²	0.0004	0.0004	0.0004	0.0012	0.0012	0.0012	0.0024	0.0042	0.0042	0.0072	0.0072	0.0116	0.0116	0.022	0.022	0.061
Maximum angular acceleration		ɑ	rad/s²	5000	5000	5000	6500	6500	6500	14600	7500	7500	6000	6000	4500	4500	3500	3500	10000
Case volume		V	l	0.17	0.17	0.17	0.2	0.2	0.2	0.33	0.45	0.45	0.55	0.55	0.8	0.8	1.1	1.1	2.5
Weight (approx.)		m	kg	6	6	6	9.5	9.5	9.5	13.5	18	18	23	23	32	32	45	45	73

1)	These values are valid at: - an absolute pressure of pabs = 1 bar at suction port S - for the optimum viscosity range from vopt = 36 to 16 mm2/s - with hydraulic fluid based on mineral oils
2)	Maximum speed (limiting speed) with increased inlet pressure pabs at suction port S, see the following diagram.
3)	Torque without radial force, with radial force see table "Permissible radial and axial forces of the drive shafts"

Maximum speed

Note

The values in the table are theoretical values, without consideration of efficiencies and tolerances. The values are rounded. Exceeding the maximum or falling below the minimum permissible values can lead to a loss of function, a reduction in operational service life or total destruction of the axial piston unit. Other permissible limit values, such as speed variation, reduced angular acceleration as a function of the frequency and the permissible angular acceleration at start (lower than the maximum angular acceleration) can be found in data sheet 90261.

Determining the operating characteristics
Flow		[l/min]
Torque		[Nm]
Power		[kW]

Key
Vg	Displacement per revolution [cm3]
Δp	Differential pressure [bar]
n	Rotational speed [rpm]
ηv	Volumetric efficiency
ηhm	Hydraulic-mechanical efficiency
ηt	Total efficiency (ηt = ηv • ηhm)

Hydraulic fluids

The axial piston unit is designed for operation with mineral oil HLP according to DIN 51524.

Application instructions and requirements for hydraulic fluids should be taken from the following data sheets before the start of project planning:

90220: Hydraulic fluids based on mineral oils and related hydrocarbons 90221: Environmentally acceptable hydraulic fluids 90222: Fire-resistant, water-free hydraulic fluids (HFDR, HFDU) 90223: Fire-resistan, water-containing hydraulic fluids (HFAE, HFAS, HFB, HFC) 90225: Restricted technical data for operation with fire-resistant hydraulic fluids

Viscosity and temperature of hydraulic fluids

	Viscosity	Temperature1)	Comment
Cold start	νmax ≤ 1600 mm²/s	ϑSt ≥ -40 °C	t ≤ 3 min, without load (p ≤ 50 bar), n ≤ 1000 rpm, permissible temperature difference between axial piston unit and hydraulic fluid max. 25 K
Warm-up phase	ν = 400 … 1600 mm²/s		t ≤ 15 min, p ≤ 0.7 • pnom and n ≤ 0.5 • nnom
Continuous operation	ν = 10 … 400 mm²/s3)	ϑ ≤ +103 °C	measured at bleed port R (ΔT = ca. 12 K between the bearing/shaft seal and port R)
Continuous operation	νopt = 16 … 36 mm²/s		range of optimum operating viscosity and efficiency
Short-term operation	νmin = 7 … 10 mm²/s	ϑ ≤ +103 °C	t ≤ 3 min, p ≤ 0.3 • pnom

1)	If the specified temperatures cannot be maintained due to extreme operating parameters, please contact us.
2)	Special version, please contact us.
3)	Equates e.g. with the VG 46 a temperature range of +5 °C to +85 °C (see selection diagram)

Explanatory note regarding the selection of hydraulic fluid

The hydraulic fluid should be selected such that the operating viscosity in the operating temperature range is within the optimum range (vopt see selection diagram).

Selection diagram

Filtration of the hydraulic fluid

Finer filtration improves the cleanliness level of the hydraulic fluid, which increases the service life of the axial piston unit.

A cleanliness level of at least 20/18/15 is to be maintained according to ISO 4406.

At a hydraulic fluid viscosity of less than 10 mm²/s (e.g. due to high temperatures in short-term operation) at the drain port, a cleanliness level of at least 19/17/14 according to ISO 4406 is required.

For example, the viscosity is 10 mm²/s at:

HLP 32 a temperature of 73°C HLP 46 a temperature of 85°C

Operating pressure range

Pressure at working port A or B (high-pressure side)			Definition
Nominal pressure	pnom	see table of values	The nominal pressure corresponds to the maximum design pressure.
Maximum pressure	pmax	see table of values	The maximum pressure corresponds to the maximum operating pressure within the single operating period. The sum of the single operating periods must not exceed the total operating period.
Single operating period		10 s
Total operating period		300 h
Minimum pressure	pHP min	25 bar	Minimum pressure on high-pressure side (port A or B) required to prevent damage to the axial piston unit.
Rate of pressure change	RA max	16000 bar/s	Maximum permissible rate of pressure build-up and reduction during a pressure change over the entire pressure range.
Pressure at suction port S (inlet)			Definition
Minimum pressure	ps min	0.8 bar absolute	Minimum pressure at inlet (suction port S) that is required to avoid damage to the axial piston unit. The minimum required pressure is dependent on the speed of the axial piston unit. (see diagram "Maximum speed")
Maximum pressure	ps max	30 bar absolute
Case pressure at port T			Definition
Continuous differential pressure	ΔpT cont	2 bar	Maximum averaged differential pressure at the shaft seal (case to ambient)
Maximum differential pressure	ΔpT max	see diagram "Maximum differential pressure at the shaft seal"	Intermittent differential pressure at the shaft seal (permitted at reduced speed)
Pressure peaks	pT peak	10 bar	t < 0.1 s

Note

Working pressure range valid when using hydraulic fluids based on mineral oils. Values for other hydraulic fluids, please contact us.

Pressure definition

1)	Total operating period = t1 + t2 + ... + tn

Rate of pressure change

Maximum differential pressure at the shaft seal

Note

The service life of the shaft seal is influenced by the speed of the axial piston unit and the case pressure. The service life decreases with an increase of the mean differential pressure between the case and the ambient pressure and with a higher frequency of pressure spikes. The case pressure must be equal to or higher than the ambient pressure.

Direction of flow

Direction of rotation, viewed on drive shaft	clockwise	counter-clockwise
Direction of flow	S to B	S to A

Permissible radial and axial forces of the drive shaft

Size			10			12			16		23			28			32		45		56				63			80				90			107				125			160			180		250
Drive shaft	Code		S	P	B	S	P	B	S	B	S	P	B	S	P	B	S	B	S	P	S	T	P	B	S	T	B	Q	U	P	B	Q	U	B	U	S	P	B	U	S	B	S	P	B	S	B	S, P
Maximum radial force at distance a (from shaft collar)	Fq max	kN	2.8	3	3.2	3.3	3	3.2	4.3	3.2	3.6	5.7	5.4	4.4	5.7	5.4	5.1	5.4	7.3	7.6	7.6	9.2	9.5	9.1	7.6	10.3	9.1	7.6	11.6	11.6	11.4	7.6	11.6	11.4	12.4	12.2	13.6	14.1	12.4	14.3	14.1	14.9	18.1	18.3	14.9	18.3	1.2
Maximum radial force at distance a (from shaft collar)	a	mm	16.8	16	16	16.8	16	16	16.8	16	24	16	16	24	16	16	24	16	24	18	24	24	18	18	24	24	18	24	24	20	20	24	24	20	27	33.5	20	20	27	33.5	20	33.5	25	25	33.5	25	41
Permitted torque at Fq max	Tq max	Nm	66	66	66	76	76	76	98	102	146	146	146	179	179	179	204	204	290	290	302	357	357	357	302	401	401	302	450	512	512	302	450	573	594	679	679	679	594	796	796	828	1021	1021	828	1146
Permitted differential pressure at Fq max	Δpq max	bar	400	400	400	400	400	400	385	400	400	400	400	400	400	400	400	400	400	400	339	400	400	400	301	400	400	237	352	400	400	211	314	400	349	400	400	400	298	400	400	325	400	400	289	400
Maximum axial force, when standstill or in non-pressurized conditions	+ Fax max	N	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	- Fax max	N	320	320	320	320	320	320	320	320	500	500	500	500	500	500	500	500	630	630	800	800	800	800	800	800	800	1000	1000	1000	1000	1000	1000	1000	1250	1250	1250	1250	1250	1250	1250	1600	1600	1600	1600	1600	2000
Maximum axial force, per bar operating pressure	+ Fax max	N/bar	3	3	3	3	3	3	3	3	5.2	5.2	5.2	5.2	5.2	5.2	5.2	5.2	7	7	8.7	8.7	8.7	8.7	8.7	8.7	8.7	10.6	10.6	10.6	10.6	10.6	10.6	10.6	12.9	12.9	12.9	12.9	12.9	12.9	12.9	16.7	16.7	16.7	16.7	16.7

General information

The specified values are maximum data and not approved for continuous operation. The axial force in the direction of action -Fax is to be avoided as this reduces the bearing life cycle. The output by means of belts requires special conditions. Please consult us.

Notes for size 250:

In case of radial forces limited performance data is valid. Please contact us. In case of axial forces during operation of the unit please contact us.

Effect of radial force Fq on the service life of bearings

By selecting a suitable direction of radial force Fq the load on the bearings caused by the internal rotary group forces can be reduced, thus optimizing the service life of the bearings. Recommended position of mating gear is dependent on direction of rotation. Examples:

Toothed gear drive, size 10 … 180

Toothed gear drive, size 250

1	Direction of rotation "clockwise", pressure at port B
2	Direction of rotation "counter-clockwise", pressure at port A

Long-Life bearing

Size 250

For long service life and use with HF hydraulic fluids. Identical external dimensions as version with standard bearings. Subsequent conversion to long-life bearings is possible. Bearing and case flushing via port U is recommended.

Bearing flushing

Flushing flow (recommended)

Size		250
Flushing flow qv	l/min	10

Size 10 … 16

Drive shafts S, P and B

1)	Toothing data valid for basic number of teeth 48
2)	Thread according to ASME B1.1
3)	Center bore according to DIN 332 (thread according to DIN 13)

Ports

Size			10	12	16
B (A)	Working port	Size	1 1/16 in 12UN-2B; 20 mm deep
		Standard 1)	ISO 11926
		State on delivery	With protective cover (must be connected)
S	Suction port	Size	1 5/16 in 12UN-2B; 20 mm deep
		Standard 1)	ISO 11926
		State on delivery	With protective cover (must be connected)
T1	Drain port	Size	9/16 in 18UNF-2B; 13 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	With protective cover (must be connected)
T2	Drain port	Size	9/16 in 18UNF-2B; 13 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	Plugged (observe installation instructions)
R	Air bleed port	Size	5/16 in 24UNF-2B; 10 mm deep
		Standard 1)	ISO 11926
		State on delivery	Plugged

1)	The spot face can be deeper than specified in the appropriate standard.
2)	Unless otherwise specified. Other layouts on request.

Size 23 … 180

Size	D1		D3	D4	D6	D8	D11	D12	D13	D14	D15	D16	D17	D18	D20	D22	D25	D28	D29	D32	D40	D41	D42	D43	D44
Size	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm
23	127	0 - 0.05	210	120	60	20	12.7	70	161	91	186	14	27	125	59	31	146	162	14.3	106	18.2	40.5	13	22.2	47.6
28	127	0 - 0.05	210	120	60	20	12.7	70	161	91	186	14	27	125	59	31	146	162	14.3	106	18.2	40.5	13	22.2	47.6
32	127	0 - 0.05	210	120	60	20	12.7	70	161	91	186	14	27	125	59	31	146	162	14.3	106	18.2	40.5	13	22.2	47.6
45	127	0 - 0.05	230	132	64	20	12.7	80	179	102	205	20	30	133	66	34	146	162	14.3	118	23.8	50.8	19	26.2	52.4
56	127	0 - 0.05	248	141	68	20	12.7	87	195	109	221	23	33	143	74	36	146	162	14.3	128	23.8	50.8	19	26.2	52.4
63	127	0 - 0.05	248	141	68	20	12.7	87	195	109	221	23	33	143	74	36	146	162	14.3	128	23.8	50.8	19	26.2	52.4
80	127	0 - 0.05	282	158	73	20	12.7	99	225	122	253	25	41	161	93	40	146	162	14.3	183	27.8	57.2	25	30.2	58.7
90	127	0 - 0.05	282	158	73	20	12.7	99	225	122	253	25	41	161	93	40	146	162	14.3	183	27.8	57.2	25	30.2	58.7
107	152.4	0 - 0.05	306	173	89	25	12.7	110	246	136	277	20	43	175	96.9	44	200	228.6	20.6	150	31.8	66.7	32	35.7	69.9
125	152.4	0 - 0.05	306	173	89	25	12.7	110	246	136	277	20	43	175	96.9	44	200	228.6	20.6	150	31.8	66.7	32	35.7	69.9
160	152.4	0 - 0.05	326	189	101	25	12.7	121	269	149	303	15	47	190	104	45	200	229	21	180	31.8	66.7	32	35.7	69.9
180	152.4	0 - 0.05	326	189	101	25	12.7	121	269	149	303	15	47	190	104	45	200	229	21	180	31.8	66.7	32	35.7	69.9

Drive shafts S and U

1)	Thread according to ASME B1.1

Splined shaft SAE J744

NG	Code	Designation 1)	Thread G	N2	N3	N4	N5	ØN6	N9	⌀N10
NG	Code	Designation 1)	Thread G	mm	mm	mm	mm	mm	mm	mm
23	S	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	35	55.9	80
28	S	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	35	55.9	80
32	S	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	35	35	55.9	80
45	S	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	35	55.9	95
56	S	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	40	55.9	105
56	T	1 3/8 in 21T 16/32 DP	7/16-14UNC-2B	9.5	28	40	48	40	55.9	105
63	S	1 1/4 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	40	55.9	105
63	T	1 3/8 in 21T 16/32 DP	7/16-14UNC-2B	9.5	28	40	48	40	55.9	105
80	Q	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	45	56	115
80	U	1 3/8 in 21T 16/32 DP	7/16-14UNC-2B	9.5	28	40	48	45	56	115
90	Q	1 1/4 in 14T 12/24 DP	7/16-14UNC-2B	9.5	28	40	48	45	56	115
90	U	1 3/8 in 21T 16/32 DP	7/16-14UNC-2B	9.5	28	40	48	45	56	115
107	U	1 1/2 in 23T 16/32 DP	5/8-11UNC-2B	12	36	56	62	50	69.9	125
107	S	1 3/4 in 13T 8/16 DP	5/8-11UNC-2B	12	36	55	67	50	74.9	125
125	U	1 1/2 in 23T 16/32 DP	5/8-11UNC-2B	12	36	56	62	50	69.9	125
125	S	1 3/4 in 13T 8/16 DP	5/8-11UNC-2B	12	36	55	67	50	74.9	125
160	S	1 3/4 in 13T 8/16 DP	5/8-11UNC-2B	12	36	55	67	60	74.9	140
180	S	1 3/4 in 13T 8/16 DP	5/8-11UNC-2B	12	36	55	67	60	74.9	140

1)	Toothing data valid for basic number of teeth 48

Drive shafts P and B

1)	Center bore according to DIN 332 (thread according to DIN 13)

Parallel keyed shaft DIN 6885

NG	Code	Designation	Thread G	⌀N1		N2	N3	N5	⌀N6	N7	N8	N9	⌀N10
NG	Code	Designation	Thread G	mm	mm	mm	mm	mm	mm	mm	mm	mm	mm
23	P	⌀25, AS8x7x40	M8 × 1.25	25	+ 0.015 + 0.002	6	19	50	35	28	8	57.9	80
23	B	⌀30, AS8x7x50	M10 × 1.5	30	+ 0.015 + 0.002	7.5	22	50	35	33	8	57.9	80
28	P	⌀25, AS8x7x40	M8 × 1.25	25	+ 0.015 + 0.002	6	19	50	35	28	8	57.9	80
28	B	⌀30, AS8x7x50	M10 × 1.5	30	+ 0.015 + 0.002	7.5	22	50	35	33	8	57.9	80
32	B	⌀30, AS8x7x50	M10 × 1.5	30	+ 0.015 + 0.002	7.5	22	50	35	33	8	57.9	80
45	P	⌀30, AS8x7x50	M12 × 1.75	30	+ 0.015 + 0.002	9.5	28	60	35	33	8	67.9	95
56	P	⌀30, AS8x7x50	M12 × 1.75	30	+ 0.015 + 0.002	9.5	28	60	40	33	8	67.9	105
56	B	⌀35, AS10x8x50	M12 × 1.75	35	+ 0.018 + 0.002	9.5	28	60	40	38	10	67.9	105
63	B	⌀35, AS10x8x50	M12 × 1.75	35	+ 0.018 + 0.002	9.5	28	60	40	38	10	67.9	105
80	P	⌀35, AS10x8x56	M12 × 1.75	35	+ 0.018 + 0.002	9.5	28	70	45	38	10	78	115
80	B	⌀40, AS12x8x56	M16 × 2	40	+ 0.018 + 0.002	12	36	70	45	43	12	78	115
90	B	⌀40, AS12x8x56	M16 × 2	40	+ 0.018 + 0.002	12	36	70	45	43	12	78	115
107	P	⌀40, AS12x8x63	M12 × 1.75	40	+ 0.018 + 0.002	9.5	28	80	50	43	12	87.9	125
107	B	⌀45, AS14x9x63	M16 × 2	45	+ 0.018 + 0.002	12	36	80	50	48.5	14	87.9	125
125	B	⌀45, AS14x9x63	M16 × 2	45	+ 0.018 + 0.002	12	36	80	50	48.5	14	87.9	125
160	P	⌀45, AS14x9x70	M16 × 2	45	+ 0.018 + 0.002	12	36	90	60	48.5	14	97.9	140
160	B	⌀50, AS14x9x70	M16 × 2	50	+ 0.018 + 0.002	12	36	90	60	53.5	14	97.9	140
180	B	⌀50, AS14x9x70	M16 × 2	50	+ 0.018 + 0.002	12	36	90	60	53.5	14	97.9	140

Ports

Size			23	28	32	45	56	63	80	90	107	125	160	180
B (A)	Working port	Size	1/2 in			3/4 in			1 in		1 1/4 in
		Standard 1)	Dimensions according to SAE J518
		Fastening thread	5/16 in 18UNC-2B; 18 mm deep			3/8 in 16UNC-2B; 21 mm deep	3/8 in 16UNC-2B; 18 mm deep		7/16 in 14UNC-2B; 22 mm deep		1/2 in 13UNC-2B; 19 mm deep
		State on delivery	With protective cover (must be connected)
S	Suction port	Size	3/4 in			1 in			1 1/4 in				1 1/2 in
		Standard	Dimensions according to SAE J518 1)
		Fastening thread	3/8 in 16UNC-2B; 20 mm deep						7/16 in 14UNC-2B; 26 mm deep		7/16 in 14UNC-2B; 24 mm deep		1/2 in 13UNC-2B; 24 mm deep
		State on delivery	With protective cover (must be connected)
T1	Drain port	Size	3/4 in 16UNF-2B; 15 mm deep						7/8 in 14UNF-2B; 17 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	With protective cover (observe installation instructions)
T2	Drain port	Size	3/4 in 16UNF-2B; 15 mm deep						7/8 in 14UNF-2B; 17 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	Plugged (observe installation instructions)
R	Air bleed port	Size	5/6 in 24UNF-2B; 10 mm deep			7/16 in 24UNF-2B; 12 mm deep			7/16 in 20UNF-2B; 12 mm deep				9/16 in 20UNF-2B; 13 mm deep
		Standard 1)	ISO 11926
		State on delivery	Plugged

1)	The spot face can be deeper than specified in the appropriate standard.
2)	Unless otherwise specified. Other layouts on request.

Size 250

Drive shafts S and K

1)	Toothing data valid for basic number of teeth 48
2)	Thread according to ASME B1.1

Ports

Size			250
B (A)	Working port	Size	1 1/4 in
		Standard 1)	Dimensions according to SAE J518
		Fastening thread	1/2 in 13UNC-2B; 20 mm deep
		State on delivery	With protective cover (must be connected)
S	Suction port	Size	2 1/2 in
		Standard	Dimensions according to SAE J518 1)
		Fastening thread	1/2 in 13UNC-2B; 20 mm deep
		State on delivery	With protective cover (must be connected)
T1	Drain port	Size	7/8 in 14UNF-2B; 17 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	With protective cover (observe installation instructions)
T2	Drain port	Size	7/8 in 14UNF-2B; 17 mm deep
		Standard 1)	ISO 11926
		State on delivery 2)	Plugged (observe installation instructions)
U	Bearing flushing	Size	9/16 in 20UNF-2B; 13 mm deep
		Standard 1)	DIN 3852
		State on delivery	Plugged

1)	The spot face can be deeper than specified in the appropriate standard.
2)	Unless otherwise specified. Other layouts on request.

Installation instructions

General

During commissioning and operation, the axial piston unit must be filled with hydraulic fluid and air bled. This must also be observed following a relatively long standstill as the axial piston unit may drain back to the reservoir via the hydraulic lines. Particularly in the installation position "drive shaft upwards" filling and air bleeding must be carried out completely as there is, for example, a danger of dry running. The case drain fluid in the housing must be directed to the reservoir via the highest available drain port (T1,T2). If a shared drain line is used for several units, make sure that the respective case pressure is not exceeded. The shared drain line must be dimensioned to ensure that the maximum permissible case pressure of all connected units is not exceeded in any operating conditions, specifically on cold start. If this is not possible, separate reservoir lines must be laid as required. To achieve favorable noise values, all connecting lines should be decoupled by using elastic elements and above-reservoir installation is to be avoided. In all operating conditions, the suction and drain lines must lead into the reservoir below the minimum fluid level. The permissible suction height hS results from the overall loss of pressure; it must not, however, be higher than hS max = 800 mm. The minimum suction pressure at port S must also not fall below 0,8 bar absolute during operation and during cold start. When designing the reservoir, ensure adequate space between the suction line and the drain line.This provides a slow-down and desgasification of the fluid and prevents that heated return flow is being drawn directly back into the suction line.

Installation position

See the following examples 1 to 8.

Further installation positions are possible upon request. Recommended installation position: 1 and 2.

Below-tank installation (standard)

Below-tank installation is at hand if the axial piston unit is installed below the minimum liquid level outside the tank.

Installation position	Air bleeding	Filling
1	‒	T1
2	‒	T2
3	‒	T1
4	R (U)	T2

Above-reservoir installation

Above-reservoir installation means that the axial piston unit is installed above the minimum fluid level of the reservoir.

Recommendation for installation position 8 (drive shaft upward): A check valve in the drain line (cracking pressure 0,5 bar) can prevent draining of the pump housing.

Installation position	Air bleeding	Filling
5	F	T1 (F)
6	F	T2 (F)
7	F	T1 (F)
8	R (U)	T2 (F)

Key
F	Filling / Air bleeding
R	Air bleed port
U	Bearing flushing / air bleed port
S	Suction port
T1, T2	Drain port
ht min	Minimum required immersion depth (200 mm)
hmin	Minimum required spacing to reservoir bottom (100 mm)
SB	Baffle (baffle plate)
hS max	Maximum permissible suction height (800 mm)

	Note: Connection F is part of the external piping and must be provided on the customer side to simplify the filling and bleeding.

Note

Connection F is part of the external piping and must be provided on the customer side to simplify the filling and bleeding.

General project planning notes

The axial piston unit is designed to be used in open circuits. The project planning, installation and commissioning of the axial piston unit require the involvement of qualified skilled personnel. Before using the axial piston unit, please read the corresponding instruction manual completely and thoroughly. If necessary, request it from Bosch Rexroth. Before finalizing your design, request a binding installation drawing. The specified datas and notes must be observed. Preservation: Our axial piston units are supplied as standard with preservative protection for a maximum of 12 months. If longer preservative protection is required (maximum 24 months), please specify this in plain text when placing your order. The preservation times are valid under optimal storage conditions. Details of these conditions can be found in the data sheet 90312 or the instruction manual. A pressure relief valve is to be provided in the hydraulic system. Observe the instructions in the instruction manual regarding tightening torques of connection threads and other threaded joints used. The notes in the instruction manual on tightening torques of the port threads and other screw joints must be observed. The ports and fastening threads are designed for the permissible maximum pressure pmax (see instruction manual). The machine or system manufacturer must ensure that the connecting elements and lines correspond to the specified operating conditions (pressure, flow, hydraulic fluid, temperature) with the necessary safety factors. The working ports and function ports are designated only to accommodate hydraulic lines.

During and shortly after operation, there is a risk of burns on the axial piston unit. Take appropriate safety measures (e.g. by wearing protective clothing).

AA2FO23/61R-VBD55

Manufacturer: Bosch Rexroth

Material #: R902156091

Model : AA2FO23/61R-VBD55

More are expected on April 30, 2025

This product is eligible for factory repair.

Table of values

Maximum speed

Note

Hydraulic fluids

Viscosity and temperature of hydraulic fluids

Explanatory note regarding the selection of hydraulic fluid

Selection diagram

Filtration of the hydraulic fluid

Operating pressure range

Note

Pressure definition

Rate of pressure change

Maximum differential pressure at the shaft seal

Note

Direction of flow

Permissible radial and axial forces of the drive shaft

General information

Notes for size 250:

Effect of radial force Fq on the service life of bearings

Toothed gear drive, size 10 … 180

Toothed gear drive, size 250

Long-Life bearing

Size 250

Bearing flushing

Flushing flow (recommended)

Size 10 … 16

Drive shafts S, P and B

Ports

Size 23 … 180

Drive shafts S and U

Splined shaft SAE J744

Drive shafts P and B

Parallel keyed shaft DIN 6885

Ports

Size 250

Drive shafts S and K

Ports

Installation instructions

General

Installation position

Below-tank installation (standard)

Above-reservoir installation

Note

General project planning notes

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Information

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