Çamaşır makinesi için V kayışlı varyatör sistemi tasarımı
V-belt variator design for washing machine
Yazar: TUNAHAN CEYHAN
Danışman: DR. ÖĞR. ÜYESİ VEDAT TEMİZ
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Konstrüksiyon Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Kayış-kasnak mekanizması = Belt-pulley mechanism ; Varyatör = Variator

Özet:
Günümüzde çamaşır makineleri hayatımızın vazgeçilmez bir parçası haline gelmiştir. Bu cihazın bu kadar vazgeçilmez oluşu da üzerinde yapılan geliştirme çalışmalarına da yansımaktadır. Beyaz eşya üreten firmalar her sene yeni modeller ile piyasada pazar payı toplamaya çalışmaktadırlar. Bu rekabetin sonucunda her geçen gün makineler daha az enerji ve su tüketerek çamaşırları etkin şekilde temizlemeyi sağlamaktadırlar. Çamaşır makineleri yükleme tipine göre temel olarak ikiye ayrılmaktadır, bunlar üstten yüklemeli ve önden yüklemeli olarak belirtilebilir. Üstten yüklemeli makinelerde çamaşırlar makinenin üstünde bulunan kapak açılarak tambur içerisine yerleştirilirler. Önden yüklemeli makinelerde kapak ön yüzün ortasında yer alır. Üstten yüklemeli makinelerden farklı olarak kapak ve tambur arasında körük bulunur. Bunun sebebi suyun kapak seviyesini geçmesi sebebiyle doğan sızdırmazlık ihtiyacıdır.
Çamaşır makinesine alternatif tahrik sistemi tasarımı yapılmadan önce piyasadaki çözümler ve bu konu üzerine alınan patentler incelenmiştir. Elde edilen bilgiler ışığında avantajlı ve dezavantajlı yanlar gözden geçirilmiştir. Mevcutta kullanılan tahrik sistemi incelenerek bu sistemin artıları ve eksileri incelenmiştir.
Bu çalışmada Arçelik'in önden yüklemeli kayış kasnak sistemi ile güç aktaran çamaşır makinelerinde kullanılmak üzere alternatif tahrik sistemi tasarlanmıştır. Sistem tasarlanırken boyut kısıtları göz önüne alınarak tasarıma başlanmıştır. Gövde derinliği için hedeflenen aralığın dışına çıkılmadan tasarımlar yapılmıştır. Güncel sistemde kullanılmakta olan kayış kasnak mekanizmalarında motor miline akuple kanallı bir kasnak, tambur miline şekil bağlı bir kasnak ve bu kasnaklar arasındaki güç aktarımını sağlayan bir poly-V kayışı bulunmaktadır. Aradaki çap farkı oranı sistemin çevrim oranını belirlemektedir. Motor momenti, tamburda bu çevrim oranı katına çıkarken, motor devri tamburda bu çevrim oranı katı kadar düşmektedir. Bunun sonucunda düşük momentler üretebilen fakat çok yüksek devirlere çıkabilmesi gereken motorların kullanılması zorunlu hale gelmiştir. Yıkama adımında tambur 50-60 d/dk olan motor devri sıkma çevriminde 1200 d/dk' ya çıkmaktadır. Tambur devirlerine karşılık gelen motor devri yıkama adımında 400-500 d/dk sıkma adımında ise 9500-10000 d/dk'dir. Tasarlanan varyatör sisteminde çiftler halinde yerleştirilmiş konik kasnaklar, bu kasnaklar arasındaki güç aktarımını sağlayan bir V kayış, V kayışın gerginliğini sağlayan bir yay ve çevrim oranının değiştirilmesini sağlayan bir santrifüj aktüatör bulunmaktadır. Projenin prototipleme aşamasında Arçelik'te bulunan hızlı prototipleme teknolojilerinden yararlanılmıştır. Burada SLS ve SLA 3 boyutlu yazıcıları ve lazer kesim tezgahlarından yararlanılmıştır. Üretilen prototipler ile konseptin doğrulanması sağlanmış ve karşılaşılan problemler incelenerek bu problemlere uygun çözümler geliştirilmiştir. Sonuç kısmında elde edilen veriler ve öğrenimler işlenmiş gelecekte gelişime açık olan yanlar anlatılmıştır.
Arçelik A.Ş. Merkez Ar-Ge Dijital Modelleme ve Yapısal Tasarım Ailesi' nde yapılan çamaşır makinesi için v kayışlı varyatör sistemi tasarımı bu tez çalışmasının içeriğini oluşturmaktadır.

Abstract:
Washing machines have become an indispensable part of our lives today. The fact that this device is so indispensable is also reflected in the development work on it. Companies producing white goods are trying to gather market share in the market with new models every year. As a result of this competition, the machines consume less energy and water day by day and provide effective cleaning of the laundry. When we look at the history of the washing machine, it is seen that the first examples appeared in 1767. In these years, mixing arms in a barrel were used to clean the laundry. In the following years, it was discovered that a barrel that could rotate around a horizontal axis offered better cleaning performance. Thanks to the rotational movement around this horizontal axis, it has been revealed that the laundry can do mechanical cleaning more effectively by rubbing more on each other. Later, all these mechanical movements performed with human power began to be driven by electric motors. First of all, semi-automatic washing machines were produced. Later, fully automatic machines were introduced to the market. Today, fully automatic washing machines are widely used.
In the washing machines we use today, the laundry is placed in a drum and cleaned. The drum is located in the tub. The tub is connected to the main body with a shock absorber and spring group. In this way, the vibrations in the tub are damped. The moment needed for the rotation movement of the drum is provided by an electric motor. Power transmission between motor and drum is provided by belt pulley system. Poly V belts are widely used in this systems. Pumps are used to dispose of the waste water formed after washing. In modern washing machines, cleaning takes place in four cycles.
In the pre-wash cycle, the detergent in the detergent box is mixed with water to reach the laundry in the drum. In this step, the laundry interacts with the detergent and chemical cleaning begins. In the main washing cycle, mechanical cleaning is carried out in addition to chemical cleaning by providing the laundry to rub on each other with various agitation algorithms. In most programs, high temperature is applied to better clean the dirt stuck on the laundry. In the rinsing cycle, it is ensured that the laundry is separated from the remaining detergent and dirt residues. This step can also be called the final wash. In the last cycle, the spin cycle, the drum reaches high speeds. In this way, it is ensured that the water particles on the laundry are removed. Thanks to the spin cycle, the drying time of the laundry after leaving the machine is significantly reduced. Washing machines are basically divided into two according to the type of loading, they can be divided into top-loading and front-loading. In top-loading machines, the laundry is placed in the drum by opening the cover on the top of the machine. In front-loading machines, the cover is located in the middle of the front wall. Unlike top-loading machines, there is a bellows between the door and the drum. The reason for this is the need for impermeability due to the fact that the water passes the door level. Top-loading washing machines are widely sold in the American market, and front-loading washing machines are sold in the European market. Before designing an alternative drive system for the washing machine, the solutions in the market and the patents on this subject were examined. In the light of the information obtained, the advantages and disadvantages were reviewed. The pros and cons of this system were examined by examining the drive system currently used.
In this study, an alternative drive system was designed to be used in washing machines that transmit power with Arçelik's front-loading belt-pulley system. While designing the system, the design was started by considering the size constraints.
In the thesis prepared, the limitations of the motors used in washing machines are mentioned in the first chapter. Afterwards, the definition of the problem determined within the scope of the thesis was made.
In the second part, the history of the washing machine is mentioned. In the following, washing machine types and parts in washing machines are mentioned. Literature researches related to the study area and detailed examination of the current propulsion system are included.
In the third section, the list of wishes was determined and alternative designs that emerged as a result of these requests were included. Value analyzes of these designs were made and the final design was selected. During the prototyping phase, rapid prototyping technologies within Arçelik were used. SLS, SLA, 3D printer and laser cutting technologies are used. The concept was verified with the prototypes produced. The problems encountered were examined in detail and appropriate solutions were developed for these problems. Since width and height are standard in washing machines, designs are made without going beyond the targeted range for body depth. In the belt pulley mechanisms used in the current system, there is a pulley coupled to the motor shaft, a pulley connected to the drum shaft and a poly-V belt that provides power transfer between these pulleys. The diameter difference ratio determines the drive ratio of the system. While the engine torque is increased by a factor of this drive ratio, the engine speed is reduced by a factor of this drive ratio in the drum. The engine speed of the drum, which is 50-60 rpm in the washing cycle, increases to 1200 rpm in the spin cycle. The engine speed corresponding to the drum revolutions is 400-500 rpm in the washing cycle and 9500-10000 rpm in the spin cycle. As a result of all these requirements, it has become necessary to use motors that can produce low torques but must be able to reach very high speeds.
Thanks to the designed variator system, it is possible to use the engines that cannot reach high revolutions in the machines. In the designed variator system, there are conical pulleys placed in pairs. The diameter of the pulleys on the drum side are larger than those on the motor side. In this way, it is ensured to reach the high moment values required in the main washing cycle. Power transmission between the conical pulley pairs is provided by the variator belt. This belt has a narrower groove angle, unlike normal v-belts. In this way, while the pulleys approach and move away from each other, larger diameter changes can be achieved at smaller axial advances. At the same time, there is a spring that maintains the tension of the belt and a centrifugal actuator that allows the drive ratio to be changed. In this actuator, there is a ramp geometry that will enable the conical pulleys to approach each other thanks to the centrifugal masses and the centrifugal movement of these masses. In this design, the weights of the masses in the actuator can be changed. In this way, it is ensured to obtain the desired drive ratio at the desired number of revolutions. Thanks to this modularity, the system can be adapted to washing machines with different requirements. The conical pulleys can return to their starting positions when the rpm of the system decreases. The pulleys coupled to the drum shaft work together with a spiral spring.
In the fourth chapter, engineering calculations are given. In this section, each part of the variator system has been processed separately and its calculations and experimental studies have been carried out. The detailed design created with the calculated and experimental data is included in this section.
In the last section, evaluations about the study are given. Opinions about the areas that are open to improvement can be found in this section.
Arçelik A.S. The V-belt variator system design for the washing machine made in the Central R&D Digital Modeling and Structural Design Family constitutes the content of this thesis.