Product Description

Bearing Feature:

Angular Contact Ball Bearing is mainly applied on high speed, high precision and little axial load occasions, such as airplane engine main shaft, machine tool main shaft and main shafts of other high speed precision machine. It can also be applied on high frequency motor, steam turbine, oil pump, air compressor and printing machine etc. It is 1 of the bearings most widely used in machinery industry.

 

Applications:

Single row angular contact ball bearings: machine tool spindles, high frequency motors, gas turbines, centrifuges, small car front wheel, differential pinion shaft, booster pumps, drilling platforms, food machinery, dividing head, fill welder, low-noise cooling towers, electrical and mechanical equipment, painting equipment, machine slot board, arc welding machine.
Double row angular contact ball bearings: pump, blower, air compressor, various types of transmission, fuel injection pumps, printing machinery, planetary reducer, extraction equipment, cycloid reducer, food packaging machinery, welding machines, electric irons, square box, gravity gun, wire strippers, axle, test analysis equipment, fine chemicals, machinery.

 

Product Number	Bore Dia (d)	Outer Dia (D)	Width (B)	Dynamic Load Rating (Cr) (kN)	Static Load Rating (Cor) (kN)
7000	10 mm	26mm	8mm	4.65	2.07
7001	12 mm	28 mm	8 mm	5.05	2.46
7002	15 mm	32 mm	9 mm	5.8	3.15
7003	17 mm	35 mm	10 mm	7.15	3.85
7004	20 mm	42mm	12mm	9.7	5.6
7005	25 mm	47mm	12mm	10.7	6.85
7006	30 mm	55mm	13mm	13.9	9.45
7007	35 mm	62mm	14mm	17.5	12.6
7008	40 mm	68mm	15mm	18.8	14.6
7009	45 mm	75mm	16mm	22.3	17.7
7571	50 mm	80mm	16mm	23.7	20.1
7011	55 mm	90mm	18mm	31	26.3
7012	60 mm	95mm	18mm	32	28.1
7013	65 mm	100mm	18mm	33.5	31.5
7014	70 mm	110mm	20mm	42.5	39.5
7015	75 mm	115mm	20mm	43.5	41.5
7016	80 mm	125mm	22mm	53.5	50.5
7017	85 mm	130mm	22mm	54.5	53.5
7018	90 mm	140mm	24mm	65	63.5
7019	95 mm	145mm	24mm	67	67
7571	100 mm	150mm	24mm	68.5	70.5
7571	105 mm	160mm	26mm	80	81.5
7571	110 mm	170mm	28mm	92	93
7571	120 mm	180mm	28mm	93.5	98.5
7026	130 mm	200mm	33mm	117	125
7571	140 mm	210mm	33mm	120	133
7030	150 mm	225mm	35mm	137	154
7032	160 mm	240mm	38mm	155	176
7034	170 mm	260mm	42mm	186	214
7036	180 mm	280mm	46mm	219	266
7038	190 mm	290mm	46mm	224	280
7040	200 mm	310mm	51mm	252	325

 

How to Calculate Stiffness, Centering Force, Wear and Fatigue Failure of Spline Couplings

There are various types of spline couplings. These couplings have several important properties. These properties are: Stiffness, Involute splines, Misalignment, Wear and fatigue failure. To understand how these characteristics relate to spline couplings, read this article. It will give you the necessary knowledge to determine which type of coupling best suits your needs. Keeping in mind that spline couplings are usually spherical in shape, they are made of steel.

Involute splines

An effective side interference condition minimizes gear misalignment. When 2 splines are coupled with no spline misalignment, the maximum tensile root stress shifts to the left by 5 mm. A linear lead variation, which results from multiple connections along the length of the spline contact, increases the effective clearance or interference by a given percentage. This type of misalignment is undesirable for coupling high-speed equipment.
Involute splines are often used in gearboxes. These splines transmit high torque, and are better able to distribute load among multiple teeth throughout the coupling circumference. The involute profile and lead errors are related to the spacing between spline teeth and keyways. For coupling applications, industry practices use splines with 25 to 50-percent of spline teeth engaged. This load distribution is more uniform than that of conventional single-key couplings.
To determine the optimal tooth engagement for an involved spline coupling, Xiangzhen Xue and colleagues used a computer model to simulate the stress applied to the splines. The results from this study showed that a “permissible” Ruiz parameter should be used in coupling. By predicting the amount of wear and tear on a crowned spline, the researchers could accurately predict how much damage the components will sustain during the coupling process.
There are several ways to determine the optimal pressure angle for an involute spline. Involute splines are commonly measured using a pressure angle of 30 degrees. Similar to gears, involute splines are typically tested through a measurement over pins. This involves inserting specific-sized wires between gear teeth and measuring the distance between them. This method can tell whether the gear has a proper tooth profile.
The spline system shown in Figure 1 illustrates a vibration model. This simulation allows the user to understand how involute splines are used in coupling. The vibration model shows 4 concentrated mass blocks that represent the prime mover, the internal spline, and the load. It is important to note that the meshing deformation function represents the forces acting on these 3 components.

Stiffness of coupling

The calculation of stiffness of a spline coupling involves the measurement of its tooth engagement. In the following, we analyze the stiffness of a spline coupling with various types of teeth using 2 different methods. Direct inversion and blockwise inversion both reduce CPU time for stiffness calculation. However, they require evaluation submatrices. Here, we discuss the differences between these 2 methods.
The analytical model for spline couplings is derived in the second section. In the third section, the calculation process is explained in detail. We then validate this model against the FE method. Finally, we discuss the influence of stiffness nonlinearity on the rotor dynamics. Finally, we discuss the advantages and disadvantages of each method. We present a simple yet effective method for estimating the lateral stiffness of spline couplings.
The numerical calculation of the spline coupling is based on the semi-analytical spline load distribution model. This method involves refined contact grids and updating the compliance matrix at each iteration. Hence, it consumes significant computational time. Further, it is difficult to apply this method to the dynamic analysis of a rotor. This method has its own limitations and should be used only when the spline coupling is fully investigated.
The meshing force is the force generated by a misaligned spline coupling. It is related to the spline thickness and the transmitting torque of the rotor. The meshing force is also related to the dynamic vibration displacement. The result obtained from the meshing force analysis is given in Figures 7, 8, and 9.
The analysis presented in this paper aims to investigate the stiffness of spline couplings with a misaligned spline. Although the results of previous studies were accurate, some issues remained. For example, the misalignment of the spline may cause contact damages. The aim of this article is to investigate the problems associated with misaligned spline couplings and propose an analytical approach for estimating the contact pressure in a spline connection. We also compare our results to those obtained by pure numerical approaches.

Misalignment

To determine the centering force, the effective pressure angle must be known. Using the effective pressure angle, the centering force is calculated based on the maximum axial and radial loads and updated Dudley misalignment factors. The centering force is the maximum axial force that can be transmitted by friction. Several published misalignment factors are also included in the calculation. A new method is presented in this paper that considers the cam effect in the normal force.
In this new method, the stiffness along the spline joint can be integrated to obtain a global stiffness that is applicable to torsional vibration analysis. The stiffness of bearings can also be calculated at given levels of misalignment, allowing for accurate estimation of bearing dimensions. It is advisable to check the stiffness of bearings at all times to ensure that they are properly sized and aligned.
A misalignment in a spline coupling can result in wear or even failure. This is caused by an incorrectly aligned pitch profile. This problem is often overlooked, as the teeth are in contact throughout the involute profile. This causes the load to not be evenly distributed along the contact line. Consequently, it is important to consider the effect of misalignment on the contact force on the teeth of the spline coupling.
The centre of the male spline in Figure 2 is superposed on the female spline. The alignment meshing distances are also identical. Hence, the meshing force curves will change according to the dynamic vibration displacement. It is necessary to know the parameters of a spline coupling before implementing it. In this paper, the model for misalignment is presented for spline couplings and the related parameters.
Using a self-made spline coupling test rig, the effects of misalignment on a spline coupling are studied. In contrast to the typical spline coupling, misalignment in a spline coupling causes fretting wear at a specific position on the tooth surface. This is a leading cause of failure in these types of couplings.

Wear and fatigue failure

The failure of a spline coupling due to wear and fatigue is determined by the first occurrence of tooth wear and shaft misalignment. Standard design methods do not account for wear damage and assess the fatigue life with big approximations. Experimental investigations have been conducted to assess wear and fatigue damage in spline couplings. The tests were conducted on a dedicated test rig and special device connected to a standard fatigue machine. The working parameters such as torque, misalignment angle, and axial distance have been varied in order to measure fatigue damage. Over dimensioning has also been assessed.
During fatigue and wear, mechanical sliding takes place between the external and internal splines and results in catastrophic failure. The lack of literature on the wear and fatigue of spline couplings in aero-engines may be due to the lack of data on the coupling’s application. Wear and fatigue failure in splines depends on a number of factors, including the material pair, geometry, and lubrication conditions.
The analysis of spline couplings shows that over-dimensioning is common and leads to different damages in the system. Some of the major damages are wear, fretting, corrosion, and teeth fatigue. Noise problems have also been observed in industrial settings. However, it is difficult to evaluate the contact behavior of spline couplings, and numerical simulations are often hampered by the use of specific codes and the boundary element method.
The failure of a spline gear coupling was caused by fatigue, and the fracture initiated at the bottom corner radius of the keyway. The keyway and splines had been overloaded beyond their yield strength, and significant yielding was observed in the spline gear teeth. A fracture ring of non-standard alloy steel exhibited a sharp corner radius, which was a significant stress raiser.
Several components were studied to determine their life span. These components include the spline shaft, the sealing bolt, and the graphite ring. Each of these components has its own set of design parameters. However, there are similarities in the distributions of these components. Wear and fatigue failure of spline couplings can be attributed to a combination of the 3 factors. A failure mode is often defined as a non-linear distribution of stresses and strains.