What is clearance and how to measure the clearance of rolling bearing?
1、 Original clearance
Clearance in free state before bearing installation. The original clearance is determined by the processing and assembly of the manufacturer.
2、 Installation clearance
Also known as fit clearance, it is the clearance when the bearing, shaft and bearing seat are installed but not working. Due to interference installation, either the inner ring is increased, or the outer ring is reduced, or both, the installation clearance is smaller than the original clearance.
3、 Working clearance
When the bearing is working, the inner ring has the maximum temperature rise and the maximum thermal expansion, which reduces the bearing clearance; At the same time, due to the load, the contact between the rolling element and the raceway produces elastic deformation, which increases the bearing clearance. Whether the bearing working clearance is larger or smaller than the installation clearance depends on the combined action of these two factors.
Some rolling bearings can not adjust the clearance, let alone disassemble. These bearings have six models, namely 0000 to 5000; Some rolling bearings can adjust the clearance, but can not be disassembled. There are 6000 type (angular contact bearing) and 1000, 2000 and 3000 type rolling bearings with conical holes in the inner ring. After adjustment, the installation clearance of these types of rolling bearings will be smaller than the original clearance; In addition, some bearings can be disassembled and the clearance can be adjusted. There are three types: 7000 (tapered roller bearing), 8000 (thrust ball bearing) and 9000 (thrust roller bearing). These three types of bearings do not have original clearance; For 6000 and 7000 type rolling bearings, the radial clearance is reduced, and the axial clearance is also reduced, and vice versa. For 8000 and 9000 type rolling bearings, only the axial clearance has practical significance.
1、 Original clearance
Clearance in free state before bearing installation. The original clearance is determined by the processing and assembly of the manufacturer.
2、 Installation clearance
Also known as fit clearance, it is the clearance when the bearing, shaft and bearing seat are installed but not working. Due to interference installation, either the inner ring is increased, or the outer ring is reduced, or both, the installation clearance is smaller than the original clearance.
3、 Working clearance
When the bearing is working, the inner ring has the maximum temperature rise and the maximum thermal expansion, which reduces the bearing clearance; At the same time, due to the load, the contact between the rolling element and the raceway produces elastic deformation, which increases the bearing clearance. Whether the bearing working clearance is larger or smaller than the installation clearance depends on the combined action of these two factors.
Some rolling bearings can not adjust the clearance, let alone disassemble. These bearings have six models, namely 0000 to 5000; Some rolling bearings can adjust the clearance, but can not be disassembled. There are 6000 type (angular contact bearing) and 1000, 2000 and 3000 type rolling bearings with conical holes in the inner ring. After adjustment, the installation clearance of these types of rolling bearings will be smaller than the original clearance; In addition, some bearings can be disassembled and the clearance can be adjusted. There are three types: 7000 (tapered roller bearing), 8000 (thrust ball bearing) and 9000 (thrust roller bearing). These three types of bearings do not have original clearance; For 6000 and 7000 type rolling bearings, the radial clearance is reduced, and the axial clearance is also reduced, and vice versa. For 8000 and 9000 type rolling bearings, only the axial clearance has practical significance.
Working condition and suffix meaning of fag self-aligning roller bearing for vibrating machinery
2021-09-10
The rolling bearing installed in the vibration exciter unit of these equipment must be able to withstand heavy load, high speed, acceleration and centrifugal force. Most of these applications work in very harsh environments, such as pollution and humidity. Fag's special self-aligning roller bearing is developed for vibration mechanical conditions and has achieved great success in practical application. In particular, the cage of rolling bearing must be able to withstand the force generated by high radial acceleration. Under worse working conditions, it may also bear the force generated by axial acceleration.
The rotation of the eccentric block will cause the deflection of the rotating shaft and the relative sliding inside the bearing. This will increase friction, resulting in an increase in bearing operating temperature. The dynamic centering capacity of special self-aligning roller bearing can reach 0.15 °. If you need to provide greater centering capability, please contact the industrial application engineer of Schaeffler Group. Basic design of FAG Special self-aligning roller bearing FAG Special self-aligning roller bearing series for vibration machinery is 223, and its main dimensions comply with e DIN 616: 1995-01 and ISO 15 standards. For the special stresses generated in vibrating machinery, FAG provides special self-aligning roller bearings with suffix t41a or t41d, which are described in section 1.5.
X-life self-aligning roller bearing 223-e1 series has very high bearing capacity by maximizing the use of bearing cross-section. For vibrating machinery, the inner diameter of X-life series self-aligning roller bearings available at present can reach 220 mm. 1.2. 1 X-life 223..- E1-t41a (d) series self-aligning roller bearing fag self-aligning roller bearing designed by E1 has no flange and has very high bearing capacity. FAG Special Bearing 223 with suffix t41a or t41d designed for vibrating machinery- E1 series also has this advantage, as shown in Figure 1. This is a new fag standard design for bearings with bearing diameters from 40 mm to 150 mm (bore series 08 to 30).
The rolling bearing installed in the vibration exciter unit of these equipment must be able to withstand heavy load, high speed, acceleration and centrifugal force. Most of these applications work in very harsh environments, such as pollution and humidity. Fag's special self-aligning roller bearing is developed for vibration mechanical conditions and has achieved great success in practical application. In particular, the cage of rolling bearing must be able to withstand the force generated by high radial acceleration. Under worse working conditions, it may also bear the force generated by axial acceleration.
The rotation of the eccentric block will cause the deflection of the rotating shaft and the relative sliding inside the bearing. This will increase friction, resulting in an increase in bearing operating temperature. The dynamic centering capacity of special self-aligning roller bearing can reach 0.15 °. If you need to provide greater centering capability, please contact the industrial application engineer of Schaeffler Group. Basic design of FAG Special self-aligning roller bearing FAG Special self-aligning roller bearing series for vibration machinery is 223, and its main dimensions comply with e DIN 616: 1995-01 and ISO 15 standards. For the special stresses generated in vibrating machinery, FAG provides special self-aligning roller bearings with suffix t41a or t41d, which are described in section 1.5.
X-life self-aligning roller bearing 223-e1 series has very high bearing capacity by maximizing the use of bearing cross-section. For vibrating machinery, the inner diameter of X-life series self-aligning roller bearings available at present can reach 220 mm. 1.2. 1 X-life 223..- E1-t41a (d) series self-aligning roller bearing fag self-aligning roller bearing designed by E1 has no flange and has very high bearing capacity. FAG Special Bearing 223 with suffix t41a or t41d designed for vibrating machinery- E1 series also has this advantage, as shown in Figure 1. This is a new fag standard design for bearings with bearing diameters from 40 mm to 150 mm (bore series 08 to 30).
Steel category and description of common bearing materials
Study on friction and wear properties of radial joint bearing
Secondly, we use the gez101es plain bearing specimens before and after optimization for wear comparison test. The test conditions are: positive pressure 607 kn, swing frequency 0.12 Hz, swing angle ± 30., Swing near the contact point of the inner and outer rings of the bearing. It is specified that one of the three conditions such as temperature rise ≥ 150 ℃, wear amount of the inner or outer ring ≥ 150 m or ring burn shall be used as the basis for judging the wear failure. No ring burn is found in the whole test process, and the temperature rise of the test piece shall not exceed 40 ℃ after 12 hours of continuous wear test, Therefore, the wear amount of 150 m is taken as the judgment basis for the termination of the test. The temperature of the bearing is monitored with a digital display thermometer, the thickness of the outer ring of the bearing is measured every 4 ~ 6 hours during the wear test, and the ball diameter of the inner ring of the bearing is measured with a micrometer. The wear thickness is equal to the initial thickness minus the thickness measured after the wear test
Secondly, we use the gez101es plain bearing specimens before and after optimization for wear comparison test. The test conditions are: positive pressure 607 kn, swing frequency 0.12 Hz, swing angle ± 30., Swing near the contact point of the inner and outer rings of the bearing. It is specified that one of the three conditions such as temperature rise ≥ 150 ℃, wear amount of the inner or outer ring ≥ 150 m or ring burn shall be used as the basis for judging the wear failure. No ring burn is found in the whole test process, and the temperature rise of the test piece shall not exceed 40 ℃ after 12 hours of continuous wear test, Therefore, the wear amount of 150 m is taken as the judgment basis for the termination of the test. The temperature of the bearing is monitored with a digital display thermometer, the thickness of the outer ring of the bearing is measured every 4 ~ 6 hours during the wear test, and the ball diameter of the inner ring of the bearing is measured with a micrometer. The wear thickness is equal to the initial thickness minus the thickness measured after the wear test
Study on transmission characteristics of cross shaft universal joint series shafting
The output characteristics under different installation conditions on the same shaft can be shown as follows: ① on the non-stationary transmission shaft, the speed, angular acceleration and torque cycle are π, the extreme value of acceleration lags behind the extreme value of speed π / 4, and the extreme value of torque lags behind the extreme value of acceleration π / 4; ② With the increase of the included angle of the universal joint, the instability between the two shafts connecting the universal joint increases, and the greater the input speed and torque, the greater the increase caused at the output end. The speed of the output shaft fluctuates up and down at a value higher than or equal to the speed of the input shaft, while the acceleration of the output shaft fluctuates up and down at a value of zero, that is, when the output shaft decelerates, The torque of the output shaft also fluctuates up and down higher than or equal to the torque value of the input shaft; ③ For the installation of ② and ③, although the transmission is relatively stable, there are requirements for the installation environment, that is, there must be an intermediate platform in the shaft system to ensure that the first, third and fifth shafts are parallel. The output of the same installation on different shafts shows that: ① for the shafting with the installation angle of each universal joint determined, the installation sequence of the angle will not affect the input and output characteristics of the shafting, but only the stability of the intermediate shafting. ② The speed, angular acceleration and torque of the output shaft of each universal joint differ by one π from the speed, angular acceleration and torque of its input shaft, that is, one cycle. ③ When the universal joint is connected in series with the shaft system, using the same rotation angle in pairs can realize the synchronous transmission of the shaft system, and using the same rotation angle continuously can obtain more stable transmission than using the same rotation angle at intervals. The smaller the difference between the rotation angles, the more stable the shaft system transmission. ④ By analyzing the curve in Figure 6, when multiple different rotation angles are connected in series with the shafting, the rotation speed order, angular acceleration order and torque order of different shafts are the same, and their respective synchronization reaches the maximum value. The latter rotation angle can offset the amplitude caused by the former rotation angle on the shafting, and the offset amount has an approximate linear relationship with the absolute value of the difference between the two rotation angles.
The relationship between the rotation angle, speed, angular acceleration and torque of any shaft in the cross shaft series shafting and the rotation angle of the input shaft of the shafting is deduced. The influence of various universal joint rotation angles on the transmission speed, angular acceleration and torque of the series shafting is analyzed by using the matlab program. From the analysis of the series shaft system of the cross shaft universal joint, it can be seen that not only the changes of the speed, angular acceleration and torque of the shaft system have cycles, but also the installation sequence of the included angle has a great impact on the dynamic characteristics of the shaft system, and its influence law can be used as a guide for the layout design of the shaft transmission system, The acceleration and torque of the intermediate shafting can be better controlled while realizing the input-output synchronous transmission of the shafting, so as to provide a reference for the vibration and noise control of the shafting.
The output characteristics under different installation conditions on the same shaft can be shown as follows: ① on the non-stationary transmission shaft, the speed, angular acceleration and torque cycle are π, the extreme value of acceleration lags behind the extreme value of speed π / 4, and the extreme value of torque lags behind the extreme value of acceleration π / 4; ② With the increase of the included angle of the universal joint, the instability between the two shafts connecting the universal joint increases, and the greater the input speed and torque, the greater the increase caused at the output end. The speed of the output shaft fluctuates up and down at a value higher than or equal to the speed of the input shaft, while the acceleration of the output shaft fluctuates up and down at a value of zero, that is, when the output shaft decelerates, The torque of the output shaft also fluctuates up and down higher than or equal to the torque value of the input shaft; ③ For the installation of ② and ③, although the transmission is relatively stable, there are requirements for the installation environment, that is, there must be an intermediate platform in the shaft system to ensure that the first, third and fifth shafts are parallel. The output of the same installation on different shafts shows that: ① for the shafting with the installation angle of each universal joint determined, the installation sequence of the angle will not affect the input and output characteristics of the shafting, but only the stability of the intermediate shafting. ② The speed, angular acceleration and torque of the output shaft of each universal joint differ by one π from the speed, angular acceleration and torque of its input shaft, that is, one cycle. ③ When the universal joint is connected in series with the shaft system, using the same rotation angle in pairs can realize the synchronous transmission of the shaft system, and using the same rotation angle continuously can obtain more stable transmission than using the same rotation angle at intervals. The smaller the difference between the rotation angles, the more stable the shaft system transmission. ④ By analyzing the curve in Figure 6, when multiple different rotation angles are connected in series with the shafting, the rotation speed order, angular acceleration order and torque order of different shafts are the same, and their respective synchronization reaches the maximum value. The latter rotation angle can offset the amplitude caused by the former rotation angle on the shafting, and the offset amount has an approximate linear relationship with the absolute value of the difference between the two rotation angles.
The relationship between the rotation angle, speed, angular acceleration and torque of any shaft in the cross shaft series shafting and the rotation angle of the input shaft of the shafting is deduced. The influence of various universal joint rotation angles on the transmission speed, angular acceleration and torque of the series shafting is analyzed by using the matlab program. From the analysis of the series shaft system of the cross shaft universal joint, it can be seen that not only the changes of the speed, angular acceleration and torque of the shaft system have cycles, but also the installation sequence of the included angle has a great impact on the dynamic characteristics of the shaft system, and its influence law can be used as a guide for the layout design of the shaft transmission system, The acceleration and torque of the intermediate shafting can be better controlled while realizing the input-output synchronous transmission of the shafting, so as to provide a reference for the vibration and noise control of the shafting.
Study on transmission characteristics of cross shaft universal joint series shafting (2)
Without considering the influence factors such as friction loss, inertia couple moment caused by angular acceleration of driven shaft and gravity, the torque relationship of input and output shaft can be obtained according to the 72 instantaneous power equality of input and output shaft in 2007 of Journal of Jiangsu University of science and Technology (NATURAL SCIENCE EDITION) Μ ｎ ＝ Μ １· ω １ ω ｎ（８） Μ ｎ ＝ Μ １·１＋（ｉ２ｎ１ －１）ｓｉｎ２ φ 1IN1 (9) observation formula (4) ～ (8) , a conclusion can be drawn that the rotation angle synchronization, speed synchronization, no acceleration and torque synchronization of the input and output shaft of the whole shaft system can be achieved only by making in1 = 1 in the assembly process of the shaft system. Therefore, it can be known that the transmission process of the universal coupling series shaft system can be realized as long as the steering angle of each universal joint is reasonably designed when the above conditions are met Inverse, that is, the instability caused by the former universal joint can be balanced by one or more universal joints behind. In the design process of series shafting, not only the synchronization of the input and output shafts of the whole shafting shall be ensured, but also the smooth transmission of the intermediate shaft shall be achieved as far as possible to avoid the vibration and damage of the shafting caused by the intermediate shaft, that is, the input and output rotation angle of each universal joint shall be reasonably designed during installation α ｋ（ｋ－１）。
Program and analyze the motion characteristics of series shafting Fig. 2 Schematic diagram of universal joint angle Fig. 2 using Matlab's powerful matrix processing ability and convenient and intuitive drawing function, The theoretical formula deduced above is programmed to calculate the transmission characteristics of any cross shaft universal joint series shaft system. The program input variables are: the number of universal joints, the rotation angle realized by each universal joint, the speed and torque of the input shaft. Figure 2 is a schematic diagram of the angle of the universal joint in the installation of a real ship shafting. Under normal operation, the input speed of the shafting is 750r / min (4500 ° / s) and the input torque is 15917n · M. the transmission characteristics of the shafting at four different installation angles are calculated by the program: ① α １＝４°、 α ２＝６°、 α ３＝－６°、 α ４＝－４°； ② α １＝６°、 α ２＝４°、 α ３＝－４°、 α ４＝－６°； ③ α １＝４°、 α ２＝－４°、 α ３＝６°、 α ４＝－６°； ④ α １＝６°、 α ２＝－６°、 α ３＝４°、 α ４＝－４°。 In order to represent the azimuth relationship between the input and output shafts of a universal joint, it is assumed that the clockwise angle is positive and vice versa. The input and output of the four cases are parallel, and the synchronous transmission of the input and output shafts is realized. The dynamic characteristics of each intermediate shaft are analyzed by program. After the program runs, the output of four installation angles is obtained, and the results are shown in Fig. 3 ~ Fig. 5. The relationships between output angle and input angle, output angular acceleration and input angle, output torque and input torque of each axis are displayed respectively, and the relationships between output angle and input angle, output angular acceleration and input angle, output torque and input torque of each axis are displayed.
Without considering the influence factors such as friction loss, inertia couple moment caused by angular acceleration of driven shaft and gravity, the torque relationship of input and output shaft can be obtained according to the 72 instantaneous power equality of input and output shaft in 2007 of Journal of Jiangsu University of science and Technology (NATURAL SCIENCE EDITION) Μ ｎ ＝ Μ １· ω １ ω ｎ（８） Μ ｎ ＝ Μ １·１＋（ｉ２ｎ１ －１）ｓｉｎ２ φ 1IN1 (9) observation formula (4) ～ (8) , a conclusion can be drawn that the rotation angle synchronization, speed synchronization, no acceleration and torque synchronization of the input and output shaft of the whole shaft system can be achieved only by making in1 = 1 in the assembly process of the shaft system. Therefore, it can be known that the transmission process of the universal coupling series shaft system can be realized as long as the steering angle of each universal joint is reasonably designed when the above conditions are met Inverse, that is, the instability caused by the former universal joint can be balanced by one or more universal joints behind. In the design process of series shafting, not only the synchronization of the input and output shafts of the whole shafting shall be ensured, but also the smooth transmission of the intermediate shaft shall be achieved as far as possible to avoid the vibration and damage of the shafting caused by the intermediate shaft, that is, the input and output rotation angle of each universal joint shall be reasonably designed during installation α ｋ（ｋ－１）。
Program and analyze the motion characteristics of series shafting Fig. 2 Schematic diagram of universal joint angle Fig. 2 using Matlab's powerful matrix processing ability and convenient and intuitive drawing function, The theoretical formula deduced above is programmed to calculate the transmission characteristics of any cross shaft universal joint series shaft system. The program input variables are: the number of universal joints, the rotation angle realized by each universal joint, the speed and torque of the input shaft. Figure 2 is a schematic diagram of the angle of the universal joint in the installation of a real ship shafting. Under normal operation, the input speed of the shafting is 750r / min (4500 ° / s) and the input torque is 15917n · M. the transmission characteristics of the shafting at four different installation angles are calculated by the program: ① α １＝４°、 α ２＝６°、 α ３＝－６°、 α ４＝－４°； ② α １＝６°、 α ２＝４°、 α ３＝－４°、 α ４＝－６°； ③ α １＝４°、 α ２＝－４°、 α ３＝６°、 α ４＝－６°； ④ α １＝６°、 α ２＝－６°、 α ３＝４°、 α ４＝－４°。 In order to represent the azimuth relationship between the input and output shafts of a universal joint, it is assumed that the clockwise angle is positive and vice versa. The input and output of the four cases are parallel, and the synchronous transmission of the input and output shafts is realized. The dynamic characteristics of each intermediate shaft are analyzed by program. After the program runs, the output of four installation angles is obtained, and the results are shown in Fig. 3 ~ Fig. 5. The relationships between output angle and input angle, output angular acceleration and input angle, output torque and input torque of each axis are displayed respectively, and the relationships between output angle and input angle, output angular acceleration and input angle, output torque and input torque of each axis are displayed.
Previous page
1
2
Next page
Contact Us
Address: Longshan, Sanjia village, Zhuhua street, Wafangdian City, Liaoning Province
Tel：13601934995
E-mail：13601934995@163.com
13601934995
E-mail
Copyright：FUJING HEAVY BEARING 辽ICP备2021010568号-1 Powerby:300.cn dalian