Contact Characteristics of a Laser Scanner Motor at Low Speed Region

    Research output: Contribution to journalArticle

    Abstract

    This paper describes a transient contact phenomenon during start-stop operation of a polygonal mirror scanner rotor driven by a flat-type brushless DC motor and supported by a passive thrust magnetic bearing and a radial air bearing. From experimental investigations, the following characteristics have been clarified. The rotor is statically unstable at very low speed region. This instability occurs because the stiffness of the air bearing is not induced without rotation and it is small at the very low speed region, whereas the magnetic negative stiffness of the magnetic bearing is existent even at zero speed. Dry contact between the rotor and stator shaft is induced at the speed lower than the threshold, because a static displacement due to non-uniform magnetization of the magnetic bearing and forced vibration due to unbalance of the rotor exceed the air gap of the air bearing. Vertical support of the rotor results in the increase of the threshold speed, in the order of several tens per cent, compared to horizontal support. Vibration due to unbalance of the rotor scarecely affects the contact phenomena. Since the dry contact reduces the lifetime of the air bearing, it is preferable to avoid the frequent start–stop operations and to keep the rotor speed higher than the threshold. The instability is reduced to adopt the magnetic bearing composed of a pair of permanent magnets.

    Original languageEnglish
    Pages (from-to)2387-2392
    Number of pages6
    JournalNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
    Volume67
    Issue number659
    DOIs
    Publication statusPublished - 2001 Jan 1

    Fingerprint

    Bearings (structural)
    Rotors
    Magnetic bearings
    Lasers
    Air
    Stiffness
    Brushless DC motors
    Thrust bearings
    Contacts (fluid mechanics)
    Stators
    Permanent magnets
    Magnetization
    Mirrors

    Keywords

    • Air Bearing Magnetic Bearing
    • Electromagnetic-Induced Vibration
    • Information Processing Equipment
    • Laser Printer
    • Scanner Motor

    ASJC Scopus subject areas

    • Mechanics of Materials
    • Mechanical Engineering
    • Industrial and Manufacturing Engineering

    Cite this

    @article{b15c2ed48e724879bc79493c62da18fa,
    title = "Contact Characteristics of a Laser Scanner Motor at Low Speed Region",
    abstract = "This paper describes a transient contact phenomenon during start-stop operation of a polygonal mirror scanner rotor driven by a flat-type brushless DC motor and supported by a passive thrust magnetic bearing and a radial air bearing. From experimental investigations, the following characteristics have been clarified. The rotor is statically unstable at very low speed region. This instability occurs because the stiffness of the air bearing is not induced without rotation and it is small at the very low speed region, whereas the magnetic negative stiffness of the magnetic bearing is existent even at zero speed. Dry contact between the rotor and stator shaft is induced at the speed lower than the threshold, because a static displacement due to non-uniform magnetization of the magnetic bearing and forced vibration due to unbalance of the rotor exceed the air gap of the air bearing. Vertical support of the rotor results in the increase of the threshold speed, in the order of several tens per cent, compared to horizontal support. Vibration due to unbalance of the rotor scarecely affects the contact phenomena. Since the dry contact reduces the lifetime of the air bearing, it is preferable to avoid the frequent start–stop operations and to keep the rotor speed higher than the threshold. The instability is reduced to adopt the magnetic bearing composed of a pair of permanent magnets.",
    keywords = "Air Bearing Magnetic Bearing, Electromagnetic-Induced Vibration, Information Processing Equipment, Laser Printer, Scanner Motor",
    author = "Hiroyuki Kawamoto",
    year = "2001",
    month = "1",
    day = "1",
    doi = "10.1299/kikaic.67.2387",
    language = "English",
    volume = "67",
    pages = "2387--2392",
    journal = "Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C",
    issn = "0387-5024",
    publisher = "Japan Society of Mechanical Engineers",
    number = "659",

    }

    TY - JOUR

    T1 - Contact Characteristics of a Laser Scanner Motor at Low Speed Region

    AU - Kawamoto, Hiroyuki

    PY - 2001/1/1

    Y1 - 2001/1/1

    N2 - This paper describes a transient contact phenomenon during start-stop operation of a polygonal mirror scanner rotor driven by a flat-type brushless DC motor and supported by a passive thrust magnetic bearing and a radial air bearing. From experimental investigations, the following characteristics have been clarified. The rotor is statically unstable at very low speed region. This instability occurs because the stiffness of the air bearing is not induced without rotation and it is small at the very low speed region, whereas the magnetic negative stiffness of the magnetic bearing is existent even at zero speed. Dry contact between the rotor and stator shaft is induced at the speed lower than the threshold, because a static displacement due to non-uniform magnetization of the magnetic bearing and forced vibration due to unbalance of the rotor exceed the air gap of the air bearing. Vertical support of the rotor results in the increase of the threshold speed, in the order of several tens per cent, compared to horizontal support. Vibration due to unbalance of the rotor scarecely affects the contact phenomena. Since the dry contact reduces the lifetime of the air bearing, it is preferable to avoid the frequent start–stop operations and to keep the rotor speed higher than the threshold. The instability is reduced to adopt the magnetic bearing composed of a pair of permanent magnets.

    AB - This paper describes a transient contact phenomenon during start-stop operation of a polygonal mirror scanner rotor driven by a flat-type brushless DC motor and supported by a passive thrust magnetic bearing and a radial air bearing. From experimental investigations, the following characteristics have been clarified. The rotor is statically unstable at very low speed region. This instability occurs because the stiffness of the air bearing is not induced without rotation and it is small at the very low speed region, whereas the magnetic negative stiffness of the magnetic bearing is existent even at zero speed. Dry contact between the rotor and stator shaft is induced at the speed lower than the threshold, because a static displacement due to non-uniform magnetization of the magnetic bearing and forced vibration due to unbalance of the rotor exceed the air gap of the air bearing. Vertical support of the rotor results in the increase of the threshold speed, in the order of several tens per cent, compared to horizontal support. Vibration due to unbalance of the rotor scarecely affects the contact phenomena. Since the dry contact reduces the lifetime of the air bearing, it is preferable to avoid the frequent start–stop operations and to keep the rotor speed higher than the threshold. The instability is reduced to adopt the magnetic bearing composed of a pair of permanent magnets.

    KW - Air Bearing Magnetic Bearing

    KW - Electromagnetic-Induced Vibration

    KW - Information Processing Equipment

    KW - Laser Printer

    KW - Scanner Motor

    UR - http://www.scopus.com/inward/record.url?scp=85024438264&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=85024438264&partnerID=8YFLogxK

    U2 - 10.1299/kikaic.67.2387

    DO - 10.1299/kikaic.67.2387

    M3 - Article

    VL - 67

    SP - 2387

    EP - 2392

    JO - Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C

    JF - Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C

    SN - 0387-5024

    IS - 659

    ER -