Moving magnet linear motor

• US 4,583,027 A
• Filed: 12/20/1984
• Issued: 04/15/1986
• Est. Priority Date: 12/27/1982
• Status: Expired due to Fees

• Current Assignee: Hitachi Metals International Limited
• Original Assignee: Hitachi Metals International Limited
• Inventors: Parker, Rollin J., Cornell, Allan W.
• Primary Examiner(s): Duggan, Donovan F.
• Application Number:
  US06/684,125
• Time in Patent Office: 481 Days
• Field of Search: 318/118-132, 310/29, 310/28, 310/15, 310/12
• US Class Current: 318/128
• CPC Class Codes: G05D 19/02 characterised by the use of electric means
• CPC Class Codes: H02K 33/06 with polarised armatures
• CPC Class Codes: H02K 33/10 wherein the alternate energisation and de-energisation of the single coil system is effected or controlled by movement of the armatures

Abstract

A linear electric motor having an oscillating linear armature disposed in proximity to a stationary stator and provided with an output member which can be directly coupled to a load. A power supply and control circuit is provided for matching the power input to the linear motor according to changing load conditions at the output.

Claims

1. A moving magnet oscillating linear motor comprising a stator having a single planar face, an electrical winding in said stator, a linear armature having a single planar face disposed in close proximity and substantially parallel to said stator planar face, said linear armature being linearly displaceable relative to said stator planar face, a pair of separate permanent magnets affixed side-by-side to said linear armature, said permanent magnets having opposite direction pole polarity in close proximity to and directed toward said winding in said stator, a flux return path member for said permanent magnets, a resilient mechanical restraining member in the form of a coil spring elastically attaching said linear armature to a stationary member, linear bearing means disposed between said stator planar face and said linear armature planar face, means connecting said linear armature to a load, and means for applying an alternately reversing voltage across said winding.

2. The motor of claim 1 wherein said means for applying an alternately reversing voltage across said winding comprises means for generating a first electrical signal of a pre-set adjustable frequency, means for generating a pulsed constant voltage second signal of a pulse width varying as a function of said frequency, means for comparing said second signal with a reference signal for generating a third signal and means for amplifying said third signal and for applying said amplified third signal across said winding.

3. The motor of claim 2 further comprising means for generating a feed-back signal as a function of the amplitude of oscillation of said linear armature, means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.

4. The motor of claim 2 further comprising means for generating a feed-back signal as a function of the frequency of oscillation of said linear armature, means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.

5. The motor of claim 2 further comprising means for generating a feed-back signal as a function of the amplitude and frequency of oscillation of said linear armature, means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.

6. In combination with an oscillating linear motor having a stator member, a linearly reciprocable armature member, an electrical winding disposed in one of said members and a pair of side-by-side permanent magnets of opposite direction pole polarity directed toward said winding and disposed in the other of said members, a power supply for applying an alternately reversing voltage across said winding comprising means for generating a first electrical signal of a pre-set adjustable frequency as a function of mechanical resilience of said linear motor, means for comparing said first signal with a reference signal and for generating a pulsed constant voltage signal of a pulse width varying as a function of said comparison, means for generating a feed-back signal, means for varying said reference signal as a function of variations of a feed-back signal, position sensor means providing said feed-back signal as a function of at least one of said armature member oscillation frequency and amplitude and means for amplifying said pulsed constant voltage signal and for applying said amplified signal across said winding, whereby the phase and frequency at which said linearly reciprocable armature member oscillates vary according to changing load conditions applied on said armature member.

7. The power supply of claim 6 wherein said means for generating said feed-back signal generates said feed-back signal as a function of the amplitude of oscillation of said linear armature member and further comprising means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.

8. The power supply of claim 6 wherein said means for generating said feed-back signal generates said feed-back signal as a function of the frequency of oscillation of said linear armature member, and further comprising means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.

9. The power supply of claim 6 wherein said means for generating said feed-back signal generates said feed-back signal as a function of the amplitude and frequency of oscillation of said linear armature member, and further comprising means for comparing said feed-back signal with said first signal, and means for generating from said comparison a control signal for varying said reference signal.