Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
1999-07-28
2001-05-22
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C310S013000, C310S027000
Reexamination Certificate
active
06236124
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improved linear motor which is capable of producing a larger thrust in a particular section than thrust produced during normal linear travel.
The linear motors are, in effect, a linearly-unrolled version of the rotary motors. Among currently-known examples of the linear motors are a linear d.c. motor (monopolar or multipolar), linear synchronous motor, linear induction motor and linear pulse motor. Thrust of the linear motors, corresponding to torque of the rotary motors, generally depends on the structure of the motors.
Of various machines etc. to which the linear motors are applied, some require a sufficiently great thrust and others do not require such a great thrust. Further, some of the former may require a great thrust only for a selected or particular working section, and they have so far employed, over an entire working range, a linear motor capable of producing the required thrust. In cases where the required thrust can not be given via the linear motor alone, an additional drive means has been used, in conjunction with or in place of the linear motor, to produce the great thrust for that particular working section.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a linear motor which is capable of producing a larger thrust in a particular section than thrust produced during normal linear travel.
It is another object of the present invention to provide a linear motor which is capable of easily producing a particular degree of thrust that can not be produced by conventional linear motors.
According to an aspect of the present invention, there is provided a linear motor which comprises: a first member tapered relative to a traveling direction thereof to provide a surface slanted relative to the traveling direction toward one end of the first member; a second member having a surface that is opposed to the slanted surface of the first member and slanted relative to the traveling direction at an angle corresponding to a slanted angle of the slanted surface of the first member; a field pole producing section that produces field poles on the slanted surface of one of the first member and second member; and an armature section provided on another of the first member and second member and including armature windings so as to produce electromagnetic poles corresponding to electric currents passed through the armature windings. Thus, the one of the first member and second member moves relative to the other of the first member and second member in response to excitation of the armature windings.
Generally, conventional-type linear motors comprise an armature section having electromagnetic poles movable in a predetermined traveling direction, and a mover or moving member provided in such a manner that its field poles face the electromagnetic poles of the armature section with a slight gap therebetween. The slight gap is always constant in width along the traveling direction irrespective of a position of the moving member; that is, the gap was a uniform-width gap along the full length thereof. According to the present invention, however, the first member (for example, a moving member) has a contour tapered relative to the traveling direction to thereby provide a surface slanted toward one of its ends in the traveling direction, and the second member (for example, a stator equipped with an armature) has a surface that is opposed to the slanted surface of the first member and also slanted relative to the traveling direction at an angle corresponding to the slanted angle of the slanted surface of the first member; thus, the opposed surface of the first and second members form a gap tapered relative to the traveling direction). Further, in the conventional-type linear motors, magnetic attraction forces are produced between the moving member and the armature core in the normal direction, thus resulting in substantial cancellation between the attraction forces. However, in the present invention, by the opposed surface of the moving member and armature core (first and second members) being arranged to form the gap tapered relative to the traveling direction, the magnetic attraction produced between the moving member and armature core (first and second members) is partly split in the traveling direction, which contributes to a greater thrust than the thrust produced by the conventional-type linear motors. Although, in the linear motor of the invention, the slight gap between the opposed surfaces of the first and second members varies in its width as the two members move relative to each other, the gap width variation can be at a very slow or mild rate because of the gradually tapered gap between the opposed slanted surfaces of the two members.
In a preferred implementation of the present invention, the first member includes magnetic and non-magnetic substance segments provided on the slanted surface thereof alternately along the traveling direction, and the armature section is provided on the second member. Further, the field pole producing section includes a magnetic field core and field windings provided independently of the first member, and the magnetic field core is fixed relative to the second member and has a surface that is opposed to the slanted surface of the first member and also slanted relative to the traveling direction at an angle corresponding to the slanted angle of the slanted surface of the first member, so that field poles corresponding to magnetic poles produced on the magnetic field core are produced on the magnetic substance segments of the first member in response to excitation of the field windings. In this instance, the magnetic substance segments are magnetically separated from each other by the non-magnetic substance segments. The magnetic field and armature cores are magnetically coupled with each other through the magnetic substance segments. Thus, N and S field poles produced on the magnetic field core are coupled with each other via the magnetic substance segments of the first (or moving) member and the armature core, thereby forming closed magnetic circuitry. Because the magnetic field and armature cores and first (or moving) member are magnetically coupled with each other via the slanted surfaces, the magnetic attraction produced between them is partly split in the traveling direction, which acts on the moving member as a axial thrust. If the field pole producing section is fixed relative to the armature section provided on the second member and the first member is a mover, then these elements will be fixed to the stator. In this case, the armature section produces a first linearly moving magnetic field and the field pole producing section produces a second linearly moving magnetic field synchronizing with the first linearly moving magnetic field in a predetermined phase relationship; this arrangement provides a synchronous-type linear motor.
In another preferred implementation of the present invention, the field pole producing section includes field windings provided on the first member and produces field poles on the slanted surface of the first member by excitation of the field windings. In this case, the magnetic field produced by the field windings need not be a moving magnetic field, because the first member and field windings are provided as an integral unit.
In still another preferred implementation of the present invention, the field pole producing section includes permanent magnets provided on the first member and produces field poles on the slanted surface of the first member by means of the permanent magnets.
In a still further preferred implementation of the present invention, the first member (e.g., moving member) is in the shape of a truncated right quadrangular pyramid having the surface slanted toward one end of the first member in the traveling direction. Each side surface of the truncated right quadrangular pyramid provides such a slanted surface. Note that the base of the truncated right quadrangular pyramid may of course be of any des
Matsubara Satoru
Nishida Satoshi
Sekiyama Tokuzou
Shibuya Hiroshi
Dinh Le Dang
Morrison & Foerster
Nisso Electric Corporation
Ramirez Nestor
LandOfFree
Linear motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Linear motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Linear motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2539707