Active balancing system and method in rotating machines

Abstract

The invention relates to an active balancing system and method in rotating machines that precisely balances rotating machines in real-time, minimising dynamic vibrations and increasing the performance and efficiency of the machines.

Description

[0001] ACTIVE BALANCING SYSTEM AND METHOD IN ROTATING MACHINES Technical field of the invention:

[0002] The invention relates to an active balancing system and method in rotating machines that provides a solution to imbalance problems occurring in rotating machines by using a real-time and innovative mass distribution system.

[0003] In addition, the invention relates to an active balancing system and method in rotating machines that precisely balances rotating machines in real-time, minimising dynamic vibrations and increasing the performance and efficiency of the machines.

[0004] State of the art:

[0005] Rotating machines are defined as machines having rotating components for the purpose of energy generation, performing mechanical work, or providing motion. These machines generally operate by converting energy into a type of rotational motion. Rotating machines are widely used in many different fields, including industry, electrical power generation, the automotive sector, and especially industrial machines and agricultural machines.

[0006] Balancing systems in rotating machines are used to minimise vibrations and imbalances that may arise from the imbalance of rotating parts. These imbalances reduce the performance of the machine, accelerate wear and tear, and may even cause failures. Balancing is particularly critical in high-speed rotating machines, because the force arising from the amount of imbalance may lead to greater vibrations as the speed increases.

[0007] Static imbalance refers to a condition in a single plane in which the centre of mass of a rotor is offset from the axis of rotation. If the thickness of the rotor is small (in this case, it may be considered as a disk), the imbalance may be balanced by adding or removing mass in a single plane.Dynamic imbalance arises from the mass distribution of the rotor being unbalanced in two or more planes and from the principal inertia axis being different from the axis of rotation. Dynamic imbalance creates a dynamic moment in the rotor or shaft bearings. For dynamic balancing, by adding or removing mass in two planes, dynamic and static imbalances are eliminated simultaneously.

[0008] The difficulty of solving the vibration problem arising from rotor imbalance has been addressed by various researchers for many years. The mass causing imbalance on the rotational axis generally changes as the machine operates or before the machine is restarted (for example, a washing machine). In both cases, active balancing techniques are required in order for the machine to operate in an optimal condition. In order to achieve the desired result, researchers have tried various balancing methods. The liquid utilisation technique generally consists of pushing water to the opposite side of the imbalance. The most suitable machines for this process are known as washing machines and centrifuges. For this purpose, a ring containing water is placed around a drum, and when the machine starts operating, the drum pushes the water in the opposite direction of the imbalance and, as a result, reduces vibration by generating a balancing force.

[0009] The first recorded use of liquid as a balancing technique was carried out by Leblanc in 1915 and was later followed by Thearle with attempts involving the use of balls. Since then, many studies on automatic balancing have been carried out by various scientists I engineers. Most of these studies generally include a rigid shaft in which balancing is performed by placing balls in one or two planes, or a flexible body is used instead of a rigid shaft in order to achieve balance.

[0010] By applying modem equipment such as optical disks to balancing methods, much quieter and smoother operation has been achieved, together with the advantage of increased service life. Recently, researchers have also begun to apply electromagnetic fields to ring balancers for mass imbalance compensation.

[0011] Although various proposals and applications have been developed in the state of the art for systems / methods for balancing rotating machines, these developments are not sufficient. Some applications related to inventions developed for this purpose are given below.The invention subject to the application numbered “WO2016138924A1” in the state of the art relates to a washing machine that provides efficient operation by balancing the unbalanced load occurring in the drum of the washing machine by means of a liquid distribution system. By controlling the water inside the drum in a controlled manner, the balancing of unbalanced loads and the minimisation of the vibration of the machine are described.

[0012] The invention subject to the application numbered “US2023057772A1” in the state of the art describes a method for actively balancing a rotor and a device having a mechanism assigned to the rotor for actively balancing the rotor and enabling active balancing during the rotation of the rotor.

[0013] In the state of the art, active and passive balancing systems and methods for balancing rotating machines are known. However, in rotating machines (rotors, shafts, washing machines, etc.), whether the imbalance is constant or time-varying, there is no system / method that can perform real-time active balancing and precisely perform this balancing operation by moving the shafts of DC linear motors located in two planes. As a result, due to the negative aspects described above and the insufficiency of existing solutions regarding the subject, it has become necessary to carry out a development in the relevant technical field.

[0014] The aim of the invention:

[0015] The most important aim of the invention is to calculate new motor shaft positions present in the balancing system by means of new values obtained from the sensors of the closed-loop designed system in the event that the amount of unbalanced mass in rotating systems changes. Thus, mass balancing can be performed actively.

[0016] Another aim of the invention is that the selected motors have high position accuracy and high positioning speeds. In this way, the balancing formed can be provided precisely and rapidly.

[0017] Another aim of the invention is the use of mass distribution control systems (MDCS). In this way, by effectively reducing vibration in rotating machines, it ensures that rotating machines operate more stably and that their service life is extended.Another aim of the invention is that the balancing system can actively perform balancing by itself while the rotating machine is in operation.

[0018] Another aim of the invention is that balancing is automatic and that the balancing accuracy is high.

[0019] Another aim of the invention is that balancing of the entire system in rotating machines can be performed in a single operation. There is no need to individually balance each part of the machines.

[0020] Another aim of the invention is that, by performing balancing in rotating machines and ensuring that the system is exposed to less vibration, the overall performance of the rotating machines is improved.

[0021] Description of the drawings:

[0022] FIGURE-1 is a drawing providing a front view of the large-scale prototype of the active balancing system in rotating machines that is the subject of the invention.

[0023] FIGURE-2 is a drawing providing a view of the A-A cross-section of the large-scale prototype of the active balancing system in rotating machines that is the subject of the invention.

[0024] FIGURE-3 is a drawing providing a view of the mass distribution control system (MDCS) balancing element used in the active balancing system in rotating machines that is the subject of the invention.

[0025] FIGURE-4 is a drawing providing a common view of the system components in the active balancing system in rotating machines that is the subject of the invention.

[0026] FIGURE-5 is a drawing providing a view of the shaft, disks, and belt-pulley mechanism of the active balancing system in rotating machines that is the subject of the invention.

[0027] FIGURE-6 is a drawing providing a view of the distances of the centres of mass of the motor shafts in the mass distribution control system (MDCS) balancing systems used in the active balancing system in rotating machines that is the subject of the invention from the shaft axis.Reference numbers:

[0028] 1. Motor 1

[0029] 2. Motor 2

[0030] 3. Slip ring

[0031] 4. Hall effect sensor

[0032] 5. Force sensor

[0033] 6. Bearing

[0034] 7. Body

[0035] 8. Disk

[0036] 9. Shaft

[0037] 10. Belt

[0038] 11. Pulley

[0039] 12. Speed-controlled DC motor

[0040] D. Balancing planes

[0041]

[0042] of the invention:

[0043] The invention relates to an active balancing system and method in rotating machines that precisely balances rotating machines in real-time, minimising dynamic vibrations and increasing the performance and efficiency of the machines.

[0044] With the invention, a solution is provided to imbalance problems occurring in rotating machines by using a real-time and innovative mass distribution system. These imbalances may adversely affect the performance and efficiency of the machines, may shorten the service life of the components, and may cause vibrations and noise. The invention solves these problems in real-time (instant).

[0045] The invention solves significant problems in the field of balancing and control of rotating machines. The invention increases the performance and efficiency of the machines by minimising dynamic vibrations, which is its main focus. By using two innovative mass distribution control systems (MDCS), the system resolves imbalance problems on the rotating shaft. These systems aim to reduce vibrations by adjusting the centres of mass of the machines. The invention performs balancing precisely in real-time. In this way,by ensuring that rotating machines operate more stably, efficiently, and with a longer service life, significant improvements are achieved in industrial applications.

[0046] The invention uses two innovative mass distribution control systems (MDCS) to eliminate balance problems on the rotating shaft (9). The MDCS consists of motor 1 (1) and motor 2 (2), which are two linear DC servo motors arranged perpendicular to each other (Figure-3), and uses the shaft weights of the motors for balancing.

[0047] To eliminate imbalance with the invention, the dynamic (imbalance) forces occurring in the shaft bearings (6) of the unbalanced system detected by the force sensors (5) are used in the static and dynamic balancing algorithm to determine the amount and location of the mass to be added in the balancing planes (D). Subsequently, the shafts of motor 1 (1 ) and motor 2 (2) in the MDCS balancing system are moved by calculating the angle and position of their centres of mass relative to the reference axis in accordance with the obtained data (Figure-6). Thus, balancing is carried out precisely. The invention increases the performance and efficiency of the machines by minimising dynamic vibrations. With the invention, detection of imbalances in rotating machines and elimination of these imbalances by using an active balancing system are ensured. In this way, machine performance is improved and the service life of the components is extended.

[0048] Since the invention performs active balancing, it always produces the same output based on sensor data under the same imbalance conditions, and the shafts of motor 1 (1) and motor 2 (2), which are linear DC servo motors, are displaced in the same manner. In this way, balancing is always carried out with the same efficiency. The invention ensures that rotating machines operate with a longer service life and more stably and reduces maintenance and repair costs.

[0049] With the invention, if amount of unbalanced mass in the system changes, mass balancing can be actively performed by means of new motor shaft positions to be calculated using new values obtained from the sensors of the closed-loop designed system. In addition, since the selected motors have high position accuracy and high positioning speeds, the balancing to be formed can be provided precisely and rapidly. With the invention, there is no need for the rotating system or the machine to stop. The invention can actively perform balancing by itself. In this way, the balancing operationis continuously carried out actively without the need for the system to stop. Balancing accuracy is high. With the invention, balancing of the entire system can be performed. Thus, there is no need for an additional balancing operation in order to balance the entire system.

[0050] The invention can perform imbalance measurement and precise balancing of the system to be balanced in real-time while it is operating. For balancing, there are two linear motors on each side, each having motor 1 (1) and motor (2). The invention can be mounted to different rotating machines by making dimensional and design changes. In order to be able to carry out tests related to the reduction or complete elimination of vibrations arising from imbalance and to compare these with computer simulations, the experimental setup prototype shown in Figure 1 is formed. This experimental setup includes a shaft (9) supported on both sides by bearings (6) and whose speed can be adjusted by a DC motor. The thickness of the shaft (9) is kept thick (rigid) in order to prevent bending during rotation.

[0051] In order to bring the system into an unbalanced state, masses (m) are placed at a desired radius (r) on two disks (8) located on the shaft (9) (Figure-5). When the shaft is rotated at any speed (co), dynamic forces and moments arising from imbalance occur in the bearings. Thus, a real unbalanced system is obtained. In real systems, the unbalanced masses (amount of imbalance) are not known. The dynamic forces created by these in the bearings (6) are measured.

[0052] In order to balance the system, the dynamic (imbalance) forces occurring in the shaft bearings (6) of the unbalanced system detected by the force sensors are used in the static and dynamic balancing algorithm (engineering calculations) to determine the amount and location of the mass in the balancing planes (these planes are the points where the z-axis intersects the shaft axes of the balancing motors in the prototype) (D). Subsequently, the shafts of motor 1 (1 ) and motor 2 (2) in the MDCS balancing system are moved by calculating the angle and position of their centres of mass relative to the reference axis in accordance with the obtained data (Figure-6). Thus, balancing is carried out precisely.

[0053] Since the amount and direction of the unbalanced mass are not known in real systems, balancing calculations are performed by making use of the forces created by these forces in the bearings (6). As seen in Figure-4, a Hall effect sensor (4) is used in thesystem in order to determine the positions (directions) of the forces to be obtained from the force sensors in the bearings (6) relative to a specific reference.

[0054] In the prototype system, in order to automatically rebalance the shaft that is made unbalanced by adding mass to two disks, balancing systems consisting of two Linear DC Motors each are placed at both ends of the shaft. The motors placed on the axis perpendicular to the shaft are as shown in Figure-3 and Figure-6.

[0055] The bodies of Linear DC motor 1 (1) and motor 2 (2) shown in Figure-6 are mounted back-to-back to each other so as to form a plus shape in each plane. The balancing amount (kg m, kg mm, or g mm) calculated from the dynamic forces obtained from the force sensors (5) in the bearings (6) and required to be added to the balancing planes (D) in which Linear DC motor 1 (1) and motor 2 (2) are located is carried out in the manner described below.

[0056] Since the bodies are placed perpendicular to the z-axis, the movement of the motor shafts occurs along the x-y axes. When the shafts of the motors, having an approximate mass of 200 g (valid only for this prototype, a different mass may be used as desired), are moved, the centre of mass of the rotating shaft also shifts, and the vector resultant of the centres of mass of the motor shafts moved along the x-y axes (Figure-6) provides the balancing amounts required for balancing. Thus, by balancing the system, the dynamic forces arising from imbalance become close to zero and the vibrations associated therewith are prevented.

[0057] Movement of the shaft (9), receiving signals from the position sensor, measurement of bearing forces, and formation of balancing amounts and vectors through the movement of the shafts of Linear DC Motor 1 (1 ) and motor 2 (2) can be easily achieved with the aid of a computer and a data acquisition system.

[0058] The balancing operations of the unbalanced system are actively carried out by a computer in real-time. In other words, the system has the capability of balancing itself. In the invention, a slip ring (3) (Figure-1 and Figure-4) is additionally used to transmit the balancing motor cables from the shaft (9) to the computer.

[0059] The real-time operating method of the invention is as follows:At t = 0, the shafts of linear DC servo motor 1 (1) and motor 2 (2) are in a centred position. Prior to the experiment, imbalance masses are fixed into the holes on the disks (8) (to create imbalance in the experimental study, imbalance is not known in the real system). With the operation of the speed-controlled DC motor (12), the belt-pulley mechanism connected to the shaft (9) is engaged, and the shaft (9) and all components connected thereto start rotating. The belt-pulley mechanism includes a belt (10) and a pulley (11).

[0060] The force sensors (5), Hall effect sensor (4), linear DC servo motor 1 (1 ), and motor 2 (2) data acquisition modules used in the system are connected to the computer. Control or monitoring operations can be performed via the computer. The cabling of the linear DC motors is arranged via slip rings (3) in order to prevent entanglement due to the rotation of the main shaft (9).

[0061] When the Hall effect sensor (4) passes tangentially to a magnet placed on the shaft (9), it sends a digital signal to the computer to which it is connected. The position of this magnet is important in terms of determining the x and y coordinates of the system. The coordinate axis on which balancing calculations are performed always remains fixed during operations.

[0062] When the shaft (9) starts rotating at the angular speed determined for the experiment, the system performs a balancing position calculation by using the force sensor (5) data obtained at the moment when the signal from the Hall effect sensor (4) is captured. As a result of this calculation, the balancing positions of the centres of mass of the shafts of linear DC servo motor 1 (1) and motor 2 (2) along the x or y axes are calculated. The closed-loop model prepared on the computer drives linear motor 1 (1) and motor 2 (2) to the required positions in order to bring the system into balance.

[0063] For example, a shaft rotating at a speed of 600 rpm passes through the origin axes 10 times per second; this means that balancing calculations can be performed 10 times per second. Determination of the balancing centres of mass and movement of the motor shafts to the relevant positions depend on the speed of the computer used and the distance of the shaft from the origin. Nevertheless, these operations are carried out very rapidly.

[0064] After balancing is completed, the system continues to operate periodically and to provide balancing within the closed-loop system on the computer by performing thesecalculations. In the event that a change occurs in the balanced system, for example when a change occurs in the amount or position of the imbalance mass, the computer detects this condition and repeats the balancing operations by making the necessary position changes in the shafts of motor 1 (1 ) and motor 2 (2).

Claims

CLAIMS1. An active balancing system in rotating machines, comprising;- at least two motor 1 (1 ) and at least two motor 2 (2), which are linear DC servo motors arranged perpendicular to each other on both sides of the active balancing system in rotating machines in order to provide balancing, and which form the mass distribution control system, and enable balancing to be performed by moving their shafts by calculating the angle and position of their centres of mass relative to the reference axis in accordance with the obtained data,- a slip ring (3) that prevents entanglement of the cabling of linear DC motor 1 (1 ) and motor 2 (2) due to rotation of the main shaft (9), and enables transmission of the cables of balancing motor 1 (1) and motor 2 (2) from the shaft (9) to the computer,- a Hall effect sensor (4) that enables determination of the x and y coordinates of the active balancing system in rotating machines by sending a digital signal to the computer to which it is connected when passing tangentially to a magnet placed on the shaft (9), thereby enabling determination of the positions of the forces to be obtained from the force sensors (5) in the bearings (6) relative to a specific reference,- force sensors (5), the data of which are used by the computer to perform balancing position calculations at the moment when the signal from the Hall effect sensor (4) is captured when the shaft (9) starts rotating at angular speed, - a bearing (6) which is the bearing of the shaft (9),- a body (7) forming the body of the active balancing system in rotating machines, - a shaft (9) supported by bearings (6) on both sides and the speed of which can be adjusted by a speed-controlled DC motor (12),- a belt (10) and a pulley (11 ) forming a belt-pulley system that transmits motion from the speed-controlled DC motor (12) to the shaft (9),- a speed-controlled DC motor (12) connected to the belt-pulley system and enabling speed adjustment of the shaft (9), and- a computer that enables simultaneous balancing by controlling and monitoring, by the computer, the force sensors (5), Hall effect sensors (4), linear DC servo motor 1 (1) and motor 2 (2) data acquisition modules used in the active balancing system in rotating machines, and that enables formation of the balancing amounts and vector by means of the movement of the shafts of linear DC motor 1 (1 ) and motor 2 (2) using these data.

2. An active balancing system in rotating machines according to claim 1 , comprising linear DC motor 1 (1) and motor 2 (2) mounted back-to-back to each other such that their bodies form a plus shape in each plane.

3. An active balancing method in rotating machines, comprising the process steps of;- positioning, by the computer, the shafts of motor 1 (1 ) and motor 2 (2) such that they are centred,- engaging the belt-pulley mechanism connected to the shaft (9) by operating the speed-controlled DC motor (12), and starting rotation of the shaft (9) and all components connected thereto,- calculating, by the computer, balancing positions, namely the balancing positions of the centres of mass of the shafts of linear DC servo motor 1 (1 ) and motor 2 (2) along the x or y axes, by using the force sensor (5) data obtained at the moment when the signal from the Hall effect sensor (4) is captured, - driving, by the computer, linear motor 1 (1) and motor 2 (2) to the required positions in order to bring the system into balance, and- completing the balancing and continuing operation of the computer to maintain balancing.

4. An active balancing method in rotating machines according to claim 3, wherein, in the event that an imbalance occurs in the active balancing system in rotating machines, the method comprises the process step of detecting the imbalance by the computer, performing calculations, and driving the shafts of motor 1 (1) and motor 2 (2) to new positions in accordance with the performed calculations.

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