RU2104606C1 - Electric drive - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: electric drive has two coaxial rotors 6, 9 rotating in opposite directions. On side of output shaft, rotors 6 and 9 are mounted in bearing on shaft 4. On other side, internal rotor 9 is coupled with driving roller 11 of flexible friction transmission that kinematically links internal rotor 9 with external rotor 6. Driving roller 11 has rim formed by oblique plate brackets possessing equal resistance for tangential-force bending. This rim compensates for geometric and other types of slip at contacting points with coupled tops and bases of cones 13 installed in bearings on shafts within holder and inclined to shaft 4 of drive through angle equal to half the angle at top of cone 13. External generating lines of other group of cones 13 contact rim 20 built up of stack of flat steel rings split at one point with splits uniformly distributed around stack circumference. Inner side of rings has grooves whose number is a multiple of the number of contacting cones 13. Triangular ridges 31 are made on external surface which enter obtuse-angle slots of ring mounted on external rotor. Flexible members installed between ridge and slot, together with groves, provide for compensation for slips at contacting points due to strain of flexible members. Obtuse-angle slots and ridges create compression forces for first and second transmission steps. Shaft speed governor has rods mounted in casing with clearance fit and fixed to holder of coupled cones. External ends of rods are joined with screw pair ensuring axial displacement of cones. EFFECT: improved compensation for geometric and other slips at contacting points. 3 cl, 5 dwg

Description

 The invention relates to mechanical engineering, in particular to electric drives.

 Drives with oppositely rotating rotors are known, which are most often used to rotate twin ship propellers. Such drives include a counter-rotor cascade with a synchronous generator (Parfenov E.E., Alekseev S.A. Research of a non-contact counter-rotor cascade with a synchronous generator. - Izvestiya AN SSSR. Energetika i transport. N 2, 1978, p. 107). The disadvantages of this drive are the use only for the propeller and the lack of regulation of the frequency of rotation of the output shafts.

 The closest to the device and the achieved result is an electromechanical system for driving propellers (a. From. USSR N 403003, H 02 P 5/34, 1973). In this drive, two coaxial rotors mounted on the housing are connected to two propellers rotating in opposite directions.

 The disadvantage of this drive is its limited use and a constant speed of the output shafts. The increase in torque is achieved only due to electromagnetic forces, which requires large dimensions of the electric drive in comparison with an equivalent mechanical transmission.

 The objective of the invention is an electric drive with one output shaft and smoothly controlling the speed of this shaft.

 The task is achieved in that the electric drive with two rotors rotating in opposite directions is mounted on a fixed axis fixed in the body, the legs of which are attached to the frame or to the machine body of the gun. On the output shaft side, which is connected to the outer rotor, bearings of the outer and inner rotors are mounted on the axis. On the output shaft, collector rings are installed that supply alternating current to the winding of the external rotor. The inner rotor has a shorted winding. On the other hand, the rotors are connected by a kinematically adjustable friction gear. The inner rotor is connected to a drive roller, which is mounted on a bearing on the drive axis. The drive roller has a rim, consisting of radial oblique plate consoles, which bends compensates for the geometric slip that occurs in the contact spots with the cones evenly spaced around the circumference of the roller rim. The number of cones is determined by the conditions of the neighborhood. The cones are paired with each other by bases and mounted in a cage on bearings and axes inclined to the drive axis at an angle equal to half the angle at the apex of the cone. In this case, the extreme inner generators of one group of cones in contact with the driving roller, and the outermost generators of another group of cones in contact with the enclosing rim, become parallel to the axis of the drive. This provides the possibility of axial movement of the cage with twin cones during operation of the drive.

 The enveloping rim through the elastic elements interacts with obtuse grooves of the ring connected to the outer rotor. The enveloping rim consists of a pack of thin flat steel rings cut in one place with a uniform arrangement of ring cuts around the circumference of the rim. On the outer surface of each ring of the rim there are uniformly arranged obtuse-angled protrusions by which each ring is supported by elastic elements mounted between the walls of the protrusions and grooves of the large ring. This interaction transmits torque, compensates for geometric sliding together with the grooves, and creates pressure forces proportional to the transmitted torque of the second and first gears.

 On the inner working surface of the rings there are grooves with a depth of 1 - 2 mm and a width of 2 - 4 mm, which, starting from the cut, are evenly spaced around the circumference of the rings, and their number is a multiple of the number of contacting cones. Grooves and elastic elements provide compensation for geometric sliding due to the deformation of the elastic elements.

где d₂ - рабочий диаметр на конусах, контактирующих с ведущим катком;
d₄ - внутренний диаметр охватывающего обода;
d₁ - диаметр ведущего катка;
d₃ - рабочий диаметр на другом спаренном конусе у полюса качения.A ferrule with paired cones is mounted in the housing on cylindrical rods that can move axially in the housing. The ends of the rods extending outward are connected to a screw pair. The screw head of this pair is rotatably fixed in the housing. When the screw rotates, the cones move axially, changing the operating parameters. The gear ratio of this mechanism is determined by the formula:

where d ₂ is the working diameter on the cones in contact with the drive roller;
d ₄ is the inner diameter of the female rim;
d ₁ - the diameter of the drive roller;
d ₃ - working diameter on another paired cone at the rolling pole.

где d_{2 max} и d_{2 min} - максимальный и минимальный диаметры на конусах, контактирующих с ведущим катком;
d_{3 max} и d_{3 min} - максимальный и минимальный рабочие диаметры на конусах, контактирующих с охватывающим ободом.The range of regulation of the friction mechanism is expressed by the formula:

where d _{2 max} and d _{2 min} - the maximum and minimum diameters on the cones in contact with the drive roller;
d _{3 max} and d _{3 min} - the maximum and minimum working diameters on the cones in contact with the enclosing rim.

 To increase the control range, bearings should be moved from the twin cones to the cage walls. This will increase the length of the working part of the forming paired cones.

где n - число консолей в пятне контакта;
t - толщина рабочей поверхности консолей на кромке;
t₁ - ширина прорези по кромке между консолями;
b - ширина обода.To ensure uniform tangential elasticity of the rim of the drive roller, it is necessary that the contact spot always contains the same number of oblique plate consoles. This is determined by the angle β of the tilt of the console to the generatrix of the cylindrical surface. This dependence is expressed by the formula:

where n is the number of consoles in the contact patch;
t is the thickness of the working surface of the consoles at the edge;
t ₁ - the width of the slot along the edge between the consoles;
b is the width of the rim.

 The height of the consoles and other parameters can be determined from the system of equations, where the first equation is the equality of the deflection arrow under the action of the tangential force per one console, and the geometric slip value in this section of the contact spot. The second equation determines the normal thickness of the console at the base, the third equation determines the bending stresses in the console under the action of shear forces.

где F - касательная сила, приходящаяся на одну консоль;
l - длина консоли в расчетном сечении;
β - угол наклона консоли к образующей цилиндра;
E - модуль упругости;
b₀ - ширина консоли у основания;
t₀ - нормальная толщина консоли у основания;
ε₁ - относительное геометрическое скольжение, компенсируемое консолью у кромки, обращенной к полюсу качения, принимаемое конструктивно из условий работы передачи;
α - угол при вершине конуса;
x - расстояние от полюса качения до расчетного сечения обода;
d₂- диаметр конуса у полюса качения;
t - толщина консоли по окружности рабочей поверхности;
L - расстояние от кромки обода у полюса качения до расчетного сечения;
n_k - число консолей в ободе;
t₁ - ширина прорези между консолями по окружности;
[σ] - допустимые напряжения на изгиб.

where F is the tangential force per console;
l is the length of the console in the design section;
β is the angle of inclination of the console to the generatrix of the cylinder;
E is the modulus of elasticity;
b ₀ is the width of the console at the base;
t ₀ is the normal thickness of the console at the base;
ε ₁ is the relative geometric slip compensated by the cantilever at the edge facing the rolling pole, taken constructively from the operating conditions of the transmission;
α is the angle at the apex of the cone;
x is the distance from the rolling pole to the calculated section of the rim;
d ₂ is the diameter of the cone at the rolling pole;
t is the thickness of the console around the circumference of the working surface;
L is the distance from the edge of the rim at the rolling pole to the design section;
n _k is the number of consoles in the rim;
t ₁ - the width of the slot between the consoles in a circle;
[σ] - permissible bending stresses.

From this system it is necessary to determine l, b ₀ and t ₀ . In addition, the roller must be checked for contact stress, taking into account the slots between the consoles.

Во второй ступени передачи охватывающий обод выполняет функции упругофрикционной передачи и создает силы прижатия для второй и первой ступеней передач. Эта сила зависит от угла наклона стенки паза к радиусу, проведенному в центр этой стенки

. Из треугольника векторов сил определяется оптимальный угол по формуле:

где γ - величина тупого угла;
d - диаметр окружности расположения середин упругих элементов;
μ_o - коэффициент трения покоя в контакте обода с конусами;
d₄ - внутренний диаметр охватывающего обода.When calculating, it is necessary to take at least three positions: L = 0,

In the second gear stage, the female rim performs the functions of an elastic-friction gear and creates pressure forces for the second and first gear stages. This force depends on the angle of inclination of the groove wall to the radius drawn to the center of this wall

. From the triangle of force vectors, the optimal angle is determined by the formula:

where γ is the value of the obtuse angle;
d is the diameter of the circumference of the midpoints of the elastic elements;
μ _o - coefficient of static friction in contact of the rim with the cones;
d ₄ is the inner diameter of the female rim.

There are grooves on the inner surface of the rim rings. One of them coincides with the section, and their number is a multiple of the number of contacting cones. On the first ring from the rolling pole, located in the direction of the top of the cone, there is a number of grooves 1k equal to the number of cones, behind this ring there are packs of rings with the number of grooves 2k, then 3k, etc. For the first ring, we set the relative geometric slip ε ₁ , which will be compensated by this ring when interacting with elastic elements.

 When the rim works, each ring works independently. When the contact spot enters the arc between the grooves, the peripheral speed of the surface of the cone is greater than the speed of the surface of the ring. In the absence of slip, the cones carry the ring along and deform the elastic elements. This compensates for the geometric slip. When contact spots approach the next grooves, the tangential force reaches a maximum, and above the grooves the ring loses adhesion with the cones and the elastic forces of the elements return to the free state. Then each contact patch passes to another arc of the ring, and the process repeats. Thus, each ring implements an average tangential force equal to half the maximum.

где K - число контактирующих конусов.The amount of slip along the length of the arc for the first ring will be:

where K is the number of contacting cones.

From this formula it can be seen that the amount of slip depends on the relative geometric slip ε ₁ and the length of the arc between the grooves.

 In order for “C” to be constant, it is necessary to reduce the length of the arc between the grooves as much by increasing the relative geometric slip.

где X_k - расстояние от полюса качения до расчетного сечения пятна контакта;
α - угол при вершине конуса;
d₃ - диаметр на конусе в полюсе качения.The relative geometric slip at any point of the contact spot for the first ring described above is expressed by the formula:

where X _k is the distance from the rolling pole to the calculated cross section of the contact spot;
α is the angle at the apex of the cone;
d ₃ - diameter on the cone in the rolling pole.

 Behind the first ring there are rings with the number of grooves 2k, and behind them 3k, 4k, etc. During the operation of the rim, the rings have relative movement, which can lead to fretting corrosion. To avoid this, between the rings you need to install anti-friction linings or cover the side surfaces with copper or graphite.

 For optimal operation of the rings of the covering rim, it is necessary to determine the stiffness of the elastic elements, which will provide maximum tangential force when compensating for sliding along the length of the arc between the grooves.

 This is achieved by solving a system of two equations, the first of which is the equality of the moments of the tangential forces and the elastic forces of the elements acting on the ring. The second equation expresses the proportionality of the geometric slip along the length of the arc to the elastic deformation of the elements corresponding to the diameters of their location.

где Q - сила прижатия кольца к конусу;
Z - жесткость упругого элемента;
h - нормальная глубина погружения выступа в упругий элемент;
l_э - длина пятна контакта выступа кольца с упругим элементом;
n_э - число упругих элементов.

where Q is the force of pressing the ring to the cone;
Z is the stiffness of the elastic element;
h is the normal immersion depth of the protrusion in the elastic element;
l _e - the length of the contact spot of the protrusion of the ring with the elastic element;
n _e - the number of elastic elements.

 From this system of equations, Z and h are determined.

 In FIG. 1 shows a longitudinal section of an electric drive; in FIG. 2 - section along A - A; in FIG. 3, 4 - lead roller; in FIG. 5 - design scheme.

In FIG. 1 body 1 paws 2 is attached to the body of the machine guns 3. In the middle of the body is a fixed axis 4. On the axis of the bearings 5, an external rotor 6 with an alternating current winding is installed. The rotor is connected to the output shaft 7, on which the collector rings are mounted 8. The internal rotor 9 with a short-circuited winding is mounted on an axis on the bearing 10. On the other hand, it is attached to the drive roller 11 of the friction gear, which is mounted on the axis on the bearing 12. The drive roller is in contact with a group of paired cones 13, the number of which is determined by the conditions of the neighborhood. Paired cones are mounted on bearings 14 and axes 15, inclined to the axis of the drive at an angle equal to half the angle at the apex of the cone (in Fig. 1 - the angle at the apex α = 60 ^o ). Paired cones can also be made of steel and ceramic (boron carbide, which in contact with steel has μ = 0.6 - 0.8).

 Bearings 14 can be placed in the walls of the cage (Fig. 5). This will increase the range of regulation.

 When the axes are inclined, the extreme inner generators of the cones in contact with the drive roller and the outermost generators of another group of cones become parallel to the axis of the drive. The axis of the cones are installed in the cage 16. The cage with cylindrical rods 17 is attached to the housing 1 with the possibility of axial movement. The outer ends of the rods are connected to a driving nut 18, which moves along a screw 19, the head of which is rotatably fixed in the housing. When the screw rotates and the drive operates, the entire system of cage rods and cones moves in the axial direction, changing the gear ratio.

 Another group of cones 13 is in contact with the enclosing rim 20, consisting of a package of flat thin steel rings cut in one place with a uniform distribution of cuts around the circumference of the rim. Such a device of the rim provides pressing it to the cones and shock-free operation.

 On the outer side of the rings there are uniformly arranged obtuse-angled protrusions 21 (Fig. 2), which are included in the same obtuse-grooves of the large ring 22, which is attached to the outer rotor 6. Between the walls of the obtuse-angled protrusions and grooves are installed elastic elements 23 (for example, rubber), whose rigidity is calculated from the system of equations (8).

 The drive roller 11 (Fig. 3 and 4) compensates for geometric and other types of slides due to the bending of the arms 24 under the action of tangential forces that occur in the absence of slippage in the contact spots.

 In the elastic-friction transmission, the contact spot and the rolling pole are different from the contact spots and the rolling pole of the same pairs with rigid rolling bodies. In the proposed transmission, in the contact of the driving roller with the cones, the linear contact spot has gaps associated with the slots between the consoles, and does not have sliding friction. Linear contact spots of the covering rim with the cones consist of the contact points of each ring with the cones, which allows to increase the allowable contact stress.

 In gears with rigid rolling bodies, the rolling pole is within the contact spot. When the rolling pole exits the contact spot, slipping occurs.

In the elastic-friction transmission, the rolling pole has theoretical significance, since there is no slip in the contact patch. In design mode, the rolling pole is outside the contact spots. This is shown by points P ₁ and P ₂ (Fig. 5). In this case, the entire rim transmits torque, which increases the traction ability of the rim.

 The parameters of the consoles 24 of the rim of the drive roller are determined from the solution of the system of equations (4). The angle of the consoles to the generatrix is determined by the formula (3).

The female rim 20 is driven, and the rolling pole of the second gear stage is shifted to the tops of the cones. This is shown in FIG. 5 point P ₂ .

При этом условии выход полюса качения за пятно контакта составит:

Такое же расстояние X₁ будет между расчетными кольцами, реализующими полную расчетную касательную силу. В промежутках между этими кольцами устанавливаются кольца с одинаковым числом канавок. Число колец с одинаковым числом канавок определяется по формуле:

где B - толщина кольца.When determining the magnitude of the output of the rolling pole beyond the contact spot, we set the value of the relative geometric slip ε ₁ , which is compensated by the first ring. Compensated slip by the first ring will be:

Under this condition, the output of the rolling pole for the contact spot will be:

The same distance X ₁ will be between the design rings that realize the full design tangential force. Between these rings, rings with the same number of grooves are installed. The number of rings with the same number of grooves is determined by the formula:

where B is the thickness of the ring.

 Intermediate rings realize a tangential force less than the calculated one.

где i определяется по формуле (1).The operation of the electric drive is based on the opposite rotation of the external and internal rotors connected by an adjustable elastic-friction transmission. When the relative rotational speed of the rotors ω ₀ and the frequency of rotation of the output shaft ω ₁ we get:

where i is determined by the formula (1).

 The advantages of the proposed electric drive: provides regulation of the frequency of rotation of the output shaft in a wide range; Compensation of geometric and other types of slides in the contact spots of friction pairs ensures operation without lubrication of friction surfaces; unloading bearings and axles from the pressing forces reduces the energy loss in the friction units and reduces their mass.

Claims (3)

 1. An electric drive containing two coaxial AC rotors mounted for rotation in opposite directions, characterized in that the rotors are mounted on bearings and an axis mounted in the housing, the inner rotor is connected to a drive roller of elastic-friction transmission in contact with a group evenly spaced along it the perimeter of paired cones and mounted in a cage on bearings and axles inclined to the axis of the drive at an angle equal to half the angle at the tops of the cones so that the extreme inner and outer The various generatrices of the paired cones become parallel to the axis of the drive, and the cage with cylindrical rods is fixed in the housing with the possibility of axial movement, the outer ends of the rods are connected to the screw nut of the screw pair, the screw head of which is rotatably fixed in the housing, the other group of cones is surrounded by an elastic-friction transmission mounted into a large ring connected to the outer rotor, which is connected to the output shaft of the drive with collector rings mounted on the shaft. 2. The drive according to claim 1, characterized in that the elastic-friction roller has a rim consisting of radial oblique consoles of equal bending resistance by tangential forces, for uniform transmission of torque, the angle of inclination of the console to the generatrix of the cylindrical working surface is determined by the formula

where n is the number of consoles in the contact patch;
t the thickness of the working surface of the console along the edge;
t _{1 the} width of the slot along the edge between the consoles;
b rim width;
β is the angle of inclination of the console to the generatrix of the cylinder;
and the console parameters are determined from the system of equations, where the first expresses the equality of the console deflection of the console in different sections and the geometric slip in the same sections, the second equation expresses the dependence of the thickness of the console at the base on the height of the console, the third equation expresses the bending stress at the base of the console under the tangent strength. 3. The electric drive according to claims 1 and 2, characterized in that the elastic-friction transmission covering the rim is made of a package of flat thin steel rings cut in one place and with uniform distribution of ring cuts around the rim circumference, obtuse-angled protrusions are made on the outer side of the rings, which include in the grooves of the same shape of a large ring connected to the outer rotor, elastic elements are installed between the lateral surfaces of the protrusions and grooves, an obtuse angle determines the force of pressing the rim to the cones when transmitting torque, on the inside On the bottom surface of each ring, grooves are made 1 to 2 mm deep and 2 to 4 mm wide, one of them coincides with the cut of the ring, on the first ring from the top of the cone there are 1K grooves, behind this ring there are rings with the number of grooves 2K, then 3K, etc. . the number of rings with the same number of grooves is determined by the formula

where N _{K is the} number of rings with the same number of grooves;
ε ₁ is the relative geometric slip compensated by the first ring of the rim (adopted structurally);
d ₄ inner diameter of the rim;
To the number of contacting cones;
In the thickness of the ring;
α is the angle at the vertices of the cones.

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