Hydraulic SAI GM motor
GM05 GM1 GM2 GM3 GM4 GM5 GM6 GM7 GM9

SAI GM series hydrulic piston motor

Crankshaft Design Radial Piston Motors
Model range: GM 05- GM9, Displacement (cc/r):59~12026, Torque (N.m): 235~47850
Rated pressure: 250 bar, Max. pressure: 350 bar, Power: 20~375 KW.
The main characteristics of this type of design are high mechanical efficiency, especially at start up, and high volumetric efficiency.
A number of features distinguish SAI Motors from other radial piston designs:


Displacement range (ml/rev.): 570 – 176720

Pivoting cylinder: the cylinder (1) remaining aligned with the eccentric of the crank (3), eliminates side loading between the cylinder and piston (2)The articulation of the cylinder-piston assembly is achieved with large diameter trunnions (4) ensuring low specific loads.Double piston support bearing: the pistons transmit their load to the shaft via a hydrostatic bearing (5) and a central roller bearing (6). The roller bearing eliminates the sliding velocity between the piston foot and the spherical piston support ring, reducing heat, friction, wearing and improving starting torque, low speed operation (reduced stick slip) and high speed operation. The hydrostatic bearing reduces metal-metal contact ensuring optimal lubrication and low friction.
Piston retaining rings (7) ensure the piston remains in contact with the shaft in all operating conditions, even during capitation.
Rotary axial distributor (8) ensures optimal distribution with short, large section ducts for reduced power-loss with high flows, and very high volumetric efficiency; extensive clearance recovery capability of the seals ensures optimal functionality throughout the motor lifetime and in conditions of thermal shock.
Interchangeable motor (9): a wide range of distributors are available with various pressure and flow control valves.
Sai GM Series Characteristics
GM Series Piston Hydraulic Motor are a result of the many years of experience gained with the preceding M, L and P Series Motors, and incorporate a number of design variations with respect to these series to in- crease the strength of the motor casings and the load capacity of the internal dynamic components. The result is a series of motors with high continuous power ratings, reduced internal loads and high mechanical and volumetric efficiency that contribute in reducing the amount of heat and therefore also the negative effects associated with it.
 

- Radial injection cylinder feed (1) eliminates direct hydraulic axial loading of the motor casing.
- Larger cylinder feed channels (1) for reduced power loss with high flows.
- Stronger castings (2) and internal reinforcement ribbing: increased casing strength and stiffness for higher internal and external load capacity.
- High load capacity bearings (3) for applications requiring high lifetime, high power/pressure, high external loads.
- Larger cylinder trunnions (4) for increased strength and stiffness and reduced specific loads.
- Cylinder trunnions with hydraulic balancing (5) to reduce friction, wearing and heat generation, enabling operation with higher powers and improved efficiency.
- Compatibility with shafts (6), adaptors, flanges, distributors of the motors of the preceding series.
- Reduced number of components for a more simple and reliable design.
- Compatibility with non-polluting oils.

Technical Data of GAI GM Motor
Table of values (theoretical values, without efficiency and tolerances; values rounded)

GM05 motor	GM05 90		GM05 110			GM05 130		GM05 150		GM05 170
Displacement    cc/rev.	86			115		129		151		166
Rated torque     Nm	343			458		513		600		660
Max. speed      rpm	1000			900		900		900		800
Max. power     KW(HP)	20(27)			20(27)		20(27)		20(27)		20(27)
GM1 motor	GM1 100	GM1 150			GM1 175	GM1 200	GM1 250	GM1 300	GM1 320	GM1 350
Displacement    cc/rev.	99	154			172	201	243	290	314	340
Rated torque     Nm	385	600			670	785	950	1130	1225	1060
Max. speed      rpm	1000	1000			900	800	700	650	600	550
Max. power     KW(HP)	48(65)	48(65)			48(65)	48(65)	48(65)	48(65)	48(65)	48(65)
GM2 motor	GM2 200	GM2 250			GM2 300	GM2 350	GM2 420	GM2 500	GM2 600	GM2 630
Displacement    cc/rev.	192	251			304	347	425	493	565	623
Rated torque     Nm	750	980			1188	1355	1658	1923	2208	2433
Max. speed      rpm	800	800			750	750	750	700	700	650
Max. power     KW(HP)	59(79)	59(79)			59(79)	59(79)	59(79)	59(79)	59(79)	59(79)

GM3 motor	GM3 500		GM3 600			GM3 700			GM3 800		GM3 900		GM3 1000
Displacement    cc/rev.	486		595			690			792		873		987
Rated torque     Nm	1895		2320			2700			3100		3400		3850
Max. speed      rpm	600		575			500			500		400		350
Max. power     KW(HP)	80(107)		80(107)			80(107)			80(107)		80(107)		80(107)
GM4 motor	GM4 600		GM4 800			GM4 900			GM4 1000		GM4 1100		GM4 1300
Displacement    cc/rev.	616		793			904			1022		1116		1316
Rated torque     Nm	2403		3100			3525			4000		4350		5125
Max. speed      rpm	550		550			450			400		400		350
Max. power     KW(HP)	100(134)		100(134)			100(134)			100(134)		100(134)		100(134)
GM5 motor	GM5 1000	GM5 1200			GM5 1300		GM5 1450			GM5 1600		GM5 1800	GM5 2000
Displacement    cc/rev.	1039	1185			1340		1462			1634		1816	2007
Rated torque     Nm	4050	4625			5225		5700			6350		7075	7825
Max. speed      rpm	450	400			400		350			300		300	250
Max. power     KW(HP)	120(160)	120(160)			120(160)		120(160)			120(160)		120(160)	120(160)
GM6 motor	GM6 1700			GM6 2100				GM6 2500				GM6 3000
Displacement    cc/rev.	1690			2127				2513				3004
Rated torque     Nm	6600			8300				9800				11875
Max. speed      rpm	400			350				300				250
Max. power     KW(HP)	170(228)			170(228)				170(228)				170(228)

PRESSURE RATINGS
All the motors are rated at a nominal continuous pressure rating of 3,650 psi. The continuous and average operating pressure, however, should be chosen in function of the required bearing lifetime (see bearing lifetime graphs). The peak operating pressures are given in the relative displacement tables. The motors may work at peak pressures for periods not exceeding 1% per minute, no more than 10 times per hour.
BACK-PRESSURE
The motors are capable of operating with high back-pressures with high efficiency, e.g. for series circuit applications.
The allowable pressures vary in function piston diameter and other factors. If the motors are required for an application with back pressure contact the technical department for further details.
CASE PRESSURE
Continuous case pressure: 15 psi, Peak case pressure: 75 psi. The case pressure is independent of the return line pressure.
For higher pressures (up to 350 psi) contact the technical department.
TORQUE
To obtain the theoretical output torque of a motor, multiply the specific torque (lb.ft/psi) given in the displacement tables by the pressure (psi). The graph below shows the output torque variation as the shaft rotates through 360°
STARTING TORQUE
Typical starting torque efficiencies are given in the performance graphs of the motors. The starting torque, how- ever, also depends on the starting position of the shaft.
LOW SPEED OPERATION
The motors are capable of operating at low speeds with a high degree of speed stability. The minimum stable speed depends on the displacement of the motor. In general the motors remain sensitive to flows of 6 in3/min + motor leak- age rate. Best results are obtained with 75-150 psi back- pressure and after the circuit has been completely purged of air by running it at 2/3 max speed for 5-10 mins.
The output torque does not fall off at very low speeds or at standstill.
NOISE LEVELS
The motors operate at lowest noise levels with a back-pres- sure of 75-150 psi, such as in closed circuits. Pressure lines and motor support structures can be efficient noise propagators or amplifiers. Pressure lines should preferably be made up of straight rigid lengths, flexible corners, firmly fixed to rigid supports at irregular intervals away from sheet paneling. Motors must be rigidly fixed to solid supports.
SILENT MOTORS
Motors can be supplied with special distributor that run nearly silently in a wide operating range.
Please contact technical department for further details.
VIBRATION
The motors can be supplied with a counterbalanced shaft to reduce vibrations at high speeds.
Please contact technical department for further details.
START-UP
Before connecting any tubes ensure that they are thoroughly cleaned, any excess material that could work loose should be removed and there should not be any oxidation of surfaces that come into contact with the oil.
Before starting work the motor casing must be filled with oil.
Before starting work the hydraulic circuit should be purged of air. This can be achieved by running the motor without load for 10-20 minutes, during which time checks should be made for leakages from connections.
During the first few hours of working under load checks should be made for leak- ages from connections and to ensure that all components remain firmly fixed to their supports.
All motors are factory tested and do not require to be run in.

 

To obtain details of this product range please contact us.