RU2224146C2 - Method to increase service life of triple-race bearing support and suspension of electromechanical device high-speed unit (versions) - Google Patents

Abstract

FIELD: mechanical engineering, instrumentation engineering. SUBSTANCE: invention can be used in devices in which reliability and long service life at considerable speeds of rotation are of vital importance. According to proposed method, intermediate race of triple-race bearing support is rotated in direction opposite to sense of rotation of its inner race at a speed defined by given mathematical expressions. Method is implemented in four design versions of suspension of high-speed unit employing triple-race supports and synchronous generator-synchronous motor set. Proposed systems can be used for suspending also slow-speed units of devices in which reliability and long service life are of vital importance. Owing to the fact that proposed invention ensures equality of dynamic loads on intermediate and outer races and rolling elements of tiers, service life of support is increased. EFFECT: increased service life. 6 cl, 4 dwg

Description

 The proposed technical solutions relate to machine and / or instrument engineering and can be used in devices to which increased demands are placed on reliability and durability at significant rotational speeds of their movable unit.

 A three-ring bearing (sometimes, for brevity, a "support") will be referred to below as one three-ring bearing or two two-ring bearings connected in series (the outer ring of one with the inner ring of the other). In the latter case, these rings and the elements connecting them perform the function of an intermediate ring of a three-ring bearing.

 We consider a suspension as two three-ring supports, the inner rings of which are placed on the shaft of the suspended unit. A component of the suspension will be considered a device that drives the intermediate rings of bearings into rotation.

 Known bearings containing three-ring [1, 2] and connected in series two-ring bearings [3]. Balls [1], cylindrical rollers [2] and conical rollers [3] are used as rolling elements in the bearings of these bearings.

 The proposed technical solutions relate to the supports of both of these types.

 In [1], essentially a method was proposed to increase the accuracy of the gyrometer by reducing the friction moment in the suspension supports of the slowly rotating inner frame of the cardan suspension of the high-speed assembly — the gyrometer rotor. For this, the intermediate ring of each support is connected with the rotor of an individual reversible (according to modern ideas [4]) electric motor rotating it with a certain constant speed, independent of the speed and direction of rotation of the inner ring.

 The amount of friction between the bodies and raceways of the bearings, which leads to wear and / or thermal jamming of the latter at high speeds, and the durability of any bearing is determined. Based on this, the method of reducing friction proposed in [1] is also advisable to use in the supports of high-speed units.

 Friction in a three-ring support depends on the rotation speed of the active (in our case, inner) ring, the associated rotation speed of the intermediate ring, the load on the support and the centrifugal forces of interaction between the bodies and raceways that arise when the separators rotate about the rolling bodies around the axis of the support and creating at their high speeds significant additional contact stresses between the surfaces of the rolling bodies and raceways of the intermediate and outer rings.

 The bearing load and the rotation speed of the active ring are predetermined values. Therefore, the durability of the support can be increased only by the optimal distribution of centrifugal forces along the tiers of the three-ring support by maintaining a certain relationship between the speeds and directions of rotation of the inner and intermediate rings.

 The disadvantage of the method described in [1], as will be shown below, when used in high-speed nodes, is the absence of such a dependence. This dependence is established by the inventions [2] and [3], which contradict each other.

 Thus, according to the invention [2], the intermediate ring is rotated at a speed equal to half the speed of rotation of the inner ring in the direction opposite to the direction of rotation of the latter.

 According to the invention [3], the intermediate ring is also rotated at a speed equal to half the speed of rotation of the inner ring, but in the same direction as that of it.

 In the support according to the invention [2], the rotation of the intermediate ring is carried out using an additional two-stage rolling body, interacting with the intermediate ring in one step, and the other with the inner ring mounted on the shaft of the rotating assembly of the device.

 In the support (in fact, the suspension) according to the invention [3], the rotation of the intermediate rings is carried out using an intermediate (according to the terminology [3]) shaft connecting these bearing rings of both bearings, connected to one additional electric drive through a V-belt drive.

 Both of these supports have limited applications and are unsuitable for use in suspensions of high-speed units of devices that are subject to increased requirements for reliability, durability, weight and dimensions, for example, in electromechanical actuators of orientation systems for spacecraft with flywheel engines in or without a gimbal or in flywheel energy storage devices of medium and low power, for which a significant kinetic moment is created not due to the mass of the flywheel, but due to high speed of its rotation.

 Consider whether the supports of the inventions [2] and [3] achieve the positive effect of increasing durability indicated there.

для радиальных и радиально-упорных подшипников со сферическими телами качения.It is known [5] that the rotation speed of a separator with rolling bodies of the inner tier of a three-ring bearing during rotation of the intermediate ring in the same direction with the inner ring is determined by the expression:
n _{c, c} = K ₁ n _c + K ₂ n _pr , (1)
the same speed when the intermediate ring rotates in the direction opposite to the inner ring - according to the expression:
n _{c, c} = K ₁ n _c + K ₂ n _pr , (2)
and the speed of rotation of the separator of the outer tier with a stationary outer ring - by the expression:
n _{c, n} = K ₃ n _ave . (3)
Here and below: indices “b” - inner, “n” - outer tiers of the bearing (bearings);
"c" is a separator, "pr" is an intermediate ring;
K ₁ , K ₂ , K ₃ - coefficients determined by the expressions:

for radial and angular contact bearings with spherical rolling elements.

In the expressions (4) - (6):
d is the average diameter of the corresponding tier of the bearing (support);
D is the diameter of the rolling body of the corresponding tier of the bearing (bearings);
α is the contact angle in the corresponding tier of the bearing (bearings).

 In this case, d, D, α are unchanged values inherent in a particular bearing.

где m - масса тела качения.It is also known [5] that the centrifugal force of interaction between the rolling body and the raceway that occurs when the separator rotates with the rolling bodies around the bearing axis is determined by the expression (in our notation):

where m is the mass of the rolling body.

 From the expressions (1) and (2) it follows that when the intermediate ring rotates in the direction of rotation of the inner ring, the rotation speed of the inner tier separator exceeds the speed of rotation of the outer tier separator. Moreover, as follows from expression (7), when using bearings of the same size (with the same m and d) [3], the centrifugal forces developed by the rolling elements of the inner tier will exceed the centrifugal forces developed by the rolling bodies of the outer tier. Therefore, the bodies and raceways of the inner tier (bearings of the central shaft [3]) are dynamically more loaded than if even the outer tier were absent and the outer rings of the bearings of the central shaft were motionless.

 Therefore, the method according to the invention [3] cannot increase the durability of the support.

 From the expression (2) it follows that when the intermediate ring rotates towards the inner, the rotation speed of the inner tier separator decreases, respectively, the centrifugal forces, the contact stresses and the spalling intensity determined by them, decrease. Therefore, the method according to the invention [2] can increase the durability of the support.

 However, as follows from expression (3), with an increase in the speed of the intermediate ring, the speed of the separator of the outer tier increases and, starting at a certain speed, the centrifugal forces developed in the outer tier will exceed the centrifugal forces developed in the inner tier of the bearing. The durability of the support in this case will decrease due to wear of bodies and raceways of its outer tier. This speed depends on the geometric dimensions of the tiers (d) and the mass of their rolling bodies (m).

Obviously, to increase the longevity of the support as a whole, it is necessary to choose a ratio of speeds n _in and n _pr so that the dynamic loads on the bodies and the raceways of the tiers are equal.

The method according to the invention [2] with a fixed ratio of speeds (n _CR = 0.5n _in ) does not take into account this need, and the proposed method takes it into account.

Приравняем выражения (7.1) и (7.2), подставим n_с,в и n_с,н из выражений (2) и (3) и после преобразований получим выражение для скорости вращения промежуточного кольца, при которой F_в=F_н, в виде

или
n_пр=К₄n_в,
где

не изменяемый для выбранной опоры коэффициент.We write expression (7) in the form:

Equating the expressions (7.1) and (7.2), we substitute n _s, and n _{s, n} of the expression (2) and (3) and after transformations we obtain an expression for the speed of rotation of the intermediate ring, in which F _in = F _n, a

or
n _ol = K ₄ n _in ,
Where

coefficient unchanged for the selected support.

Таким образом, вращение промежуточного кольца трехколечной опоры быстроходного узла в направлении, противоположном относительно направления вращения ее внутреннего кольца, со скоростью, определенной по выражениям (8) или (10), обеспечивает равенство динамических нагрузок на промежуточное и наружное кольца и тела качения ярусов и тем самым увеличивает долговечность опоры.For the support containing two serially connected two-ring one-dimensional bearings (d _n = d _in ; m _n = m _in ), expressions (8) and (9) will have the form:

Thus, the rotation of the intermediate ring of the three-ring support of the high-speed assembly in the direction opposite to the direction of rotation of its inner ring, at a speed determined by expressions (8) or (10), ensures that the dynamic loads on the intermediate and outer rings and the rolling elements of the tiers are equal thereby increasing the durability of the support.

The speed of rotation of the intermediate ring n _pr is determined during the integrated design of the high-speed assembly after determining n _in and choosing the type of support and its bearings.

В этом случае СГ, ротор которого установлен на валу быстроходного узла, служит источником питания СД, ротор которого связан с промежуточными кольцами опор подвеса. Статоры СГ и СД установлены в корпусе устройства.The method can be implemented, for example, by using a synchronous generator - synchronous motor ("SG-SD") aggregate device with a ratio of the number of pairs of generator and motor poles in the suspension of a high-speed unit

In this case, the SG, the rotor of which is mounted on the shaft of the high-speed assembly, serves as the power source of the LED, the rotor of which is connected with the intermediate rings of the suspension supports. Stators SG and SD are installed in the device casing.

 In FIG. Figures 1-4 show four options for constructing suspension schemes for a high-speed assembly using three-ring supports and an SG-SD unit.

 Figure 1 shows a structural diagram of the suspension of a high-speed assembly of an electromechanical device 1 mounted on a hollow main shaft 2. The suspension contains two three-ring rolling bearings 3 and 4, the inner rings of which are located at the ends of the main shaft, and the outer ones are in the device body. The rotation of the intermediate rings of the bearings is carried out by the bushings 5 and 6 connected to them, interconnected by an additional shaft 7 located coaxially with the main shaft 2 and driven into rotation by the SG-SD unit. The rotor 8 of the aggregate generator is mounted on the main shaft of the high-speed assembly, and its stator 9 is installed in the device’s casing and is electrically connected to the motor stator 10 also installed in the casing of the device, the rotor of which 11 is mounted on the additional shaft 7. When the high-speed assembly rotates, the SG generates electrical voltage, whose frequency is proportional to the speed of rotation of the unit, and the LED fed with this voltage rotates the sleeves 5 and 6 and the intermediate rings connected to them at a speed determined by expressions (8) and (10).

 The embodiment of the suspension scheme shown in FIG. 2 of the same as in FIG. 1, the high-speed assembly 1 also mounted on the hollow main shaft 2 differs from the previous one in that here the three-ring bearings are made by the serial connection of the two-ring bearings 12 and 13, 14 and 15 with the help of sleeves 16 and 17 connected with an additional shaft 18, driven into rotation by the same unit as in FIG. 1, by the SG-SD 8 ... 11 unit.

 In this version of the suspension, it is possible to use one-dimensional bearings in the bearings, which ensures the equality of not only dynamic, but also static loads on the bodies and raceways of the bearings and also increases the durability of the bearings.

 A variant of the suspension structural design shown in FIG. 3 differs from that shown in FIG. 1 in that the same high-speed assembly 1 is mounted on a solid shaft 19, also located in the inner rings of the three-ring bearings 3 and 4, the intermediate rings of which are connected to the bushings with axes 20 and 21 installed in the additional bearings 22 and 23, and the SG-SD unit here contains one SG 8, 9 and two LEDs, the stators of which 10 and 24 are installed in the device body, and the rotors 11 and 25 are on the axes of the bushings 20 and 21 respectively.

 This suspension option is preferable with a significant mass of the high-speed assembly, since it allows you to transfer part of the static load to the bodies and raceways of additional bearings, the inner rings of which rotate at a much lower speed than the inner rings of the three-ring bearings of the bearings, which also contributes to an increase in the durability of the bearings and the assembly as a whole .

 In the embodiment of the suspension structural design shown in FIG. 4, as in the embodiment of FIG. 2, the three-ring bearings are made by connecting the two-ring bearings 12 and 13, 14 and 15 in series using the bushings with the axles 20 as in FIG. 2 and 21, also driven into rotation by an SG-SD unit with one SG with a rotor 8 and a stator 9 and two LEDs with a stator 10, rotor 11 and stator 24, rotor 25, respectively. In this embodiment, one-dimensional bearings can also be used.

 All of the above suspensions can be used for hanging and relatively slow-moving units of devices, which also have high demands on reliability and durability.

Sources of information
1. Auth. testimonial. USSR SU 657246 A (S.V. GORIN et al.), Cl. G 01 C 19/00, 04/15/1979.

 2. Auth. testimonial. USSR SU 1401177 A1 (N.M. POTAPOV et al.), Cl. F 16 C 19/54, 07/07/1988.

 3. Auth. testimonial. USSR SU 1381279 A1 (K.K. YATSKEVICH and others), cl. F 16 C 35/07, 19/54, 03/15/1988.

 4. Gyroscopic systems. Part 3. Elements of gyroscopic devices. Ed. PELPOR D.S. M., 1972.

 5. BEISELMAN R.D. etc. Rolling bearings. Directory. M., 1975.

Claims (5)

1. A method of increasing the durability of a three-ring bearing support, according to which the intermediate ring is rotated towards the rotation of the inner ring with a speed determined by the expression

where K ₁ , K ₂ , K ₃ are the coefficients determined by the expressions:

for radial and angular contact bearings with spherical rolling elements, where in - the inner tier of the support; n is the outer tier of the support; pr - an intermediate support ring; d is the average diameter of the corresponding tier of the support; D is the diameter of the rolling body of the corresponding tier of the support; α is the contact angle in the corresponding tier of the support. 2. Suspension of a high-speed assembly of an electromechanical device, characterized in that it consists of two three-ring bearing bearings, the inner rings of which are located at the ends of the hollow main shaft of the assembly, and the outer rings are in the device housing, two bushings connected to the intermediate rings of the bearings and connected between an additional shaft located coaxially with the main shaft, as well as a synchronous generator, the rotor of which is mounted on the main shaft, and the stator in the device’s body, a synchronous motor, the rotor of which is sized It is mounted on an additional shaft, and the stator is installed in the device body and is electrically connected to the generator stator. 3. Suspension of a high-speed assembly of an electromechanical device, characterized in that it consists of two three-ring bearing bearings formed by two pairs of two-ring bearings, the first bearings of which are installed by the inner rings on the hollow main shaft of the electromechanical device, and the outer ones in the bushings connected by an additional shaft, placed coaxially with the main in the inner rings of the second bearings of the pairs, the outer rings of which are installed in the device housing, as well as the synchronous generator the stator, the rotor of which is mounted on the main shaft, and the stator - in the device casing, the synchronous motor, the rotor of which is placed on the additional shaft, the stator is installed in the device casing and is electrically connected to the generator stator. 4. Suspension of a high-speed assembly of an electromechanical device, characterized in that it consists of two three-ring bearing bearings, the inner rings of which are located on the shaft of the assembly, and the outer rings in the device housing, two bushings with axles connected to the intermediate rings of the bearings, two two-ring bearings rolling elements, the inner rings of which are mounted on the axes of the bushings, and the outer ones in the device’s body, as well as a synchronous generator, the rotor of which is mounted on the shaft of the unit, and the stator in the device’s body, two synchronous motors To rotors which are arranged on sleeves axes, and the stators are installed in the chassis and electrically connected with the stator of the synchronous generator. 5. Suspension of a high-speed assembly of an electromechanical device, characterized in that it consists of two three-ring bearing bearings formed by two pairs of two-ring bearings, the first bearings of which are mounted by inner rings on the shaft of the assembly, and the outer ones by bushings with axles, the second bearings of the pairs are installed by internal rings on the axles of the bushings, and the outer ones in the device’s body, as well as a synchronous generator, the rotor of which is mounted on the shaft of the unit, and the stator in the device’s body, and two synchronous motors, p whose holes are located on the axes of the bushings, and the stators are installed in the device casing and are electrically connected to the stator of the synchronous generator.

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