Brushless direct current motor

Claim 2

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means defining a gap through which a magnetic field flows in a direction substantially parallel to said rotary axis; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said magnetic sensitive element means including at least one Hall element and is adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 3

A brushless direct current motor as recited in claim 1, wherein said magnetic sensitive element means is mounted within an aperture in said stator.

Claim 4

A brushless direct current motor as recited in claim 1, wherein said magnetic sensitive element means is mounted within a recess in the surface of said flat stator.

Claim 5

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means defining a gap through which a magnetic field flows in a direction substantially parallel to said rotary axis; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means inclUding at least one magneto resistive element mounted thereon in said gap to thereby be within said magnetic field, said magneto resistive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magneto resistive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 6

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means defining a gap through which a magnetic field flows in a direction substantially parallel to said rotary axis; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means inclUding at least one magneto resistive element mounted thereon in said gap to thereby be within said magnetic field, said magneto resistive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magneto resistive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 7

A brushless dirrct current motor as recited in claim 4, wherein said magneto resistive element is mounted within an aperture in said stator.

Claim 8

A brushless direct current motor as recited in claim 4, wherein said magneto resistive element is mounted within a recess in a surface of said flat stator.

Claim 9

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means, said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, the angle of the sector defined between said opposed edges of each of said driving coils is equal to about 2 pi Divided by by the number of permanent magnets in each of said groups of permanent magnets, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 10

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means, said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, the angle of the sector defined between said opposed edges of each of said driving coils is equal to about 2 pi Divided by by the number of permanent magnets in each of said groups of permanent magnets, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 11

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned with said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting siGnal, the driving coils controlled by one of said magnetic sensitive element means are spaced by an angle equal to about an integral multiple of 2 pi Divided by by the number of permanent magnets in each of said groups.

Claim 12

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned with said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting siGnal, the driving coils controlled by one of said magnetic sensitive element means are spaced by an angle equal to about an integral multiple of 2 pi Divided by by the number of permanent magnets in each of said groups.

Claim 13

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal, the magnetic sensitive element means and the driving coil controlled thereby are spaced about said rotary axis such that the angle between the axis of each of said coils and said magnetic sensitive element means is equal to about the sum of an integral multiple of 2 pi Divided by by the number of permanent magnets in each group and pi Divided by by the number of permanent magnets in each group.

Claim 14

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator plate positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said driving coil means including at least two flat coils having a pair of opposed edges essentially extending radially relative to said rotary axis and defining a sector therebetween, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal, the magnetic sensitive element means and the driving coil controlled thereby are spaced about said rotary axis such that the angle between the axis of each of said coils and said magnetic sensitive element means is equal to about the sum of an integral multiple of 2 pi Divided by by the number of permanent magnets in each group and pi Divided by by the number of permanent magnets in each group.

Claim 15

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator pole positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal, said motor having at least two magnetic sensitive element means and at least two driving coils controlled by each of said magnetic sensitive element means, said magnetic sensitive element means being positioned about said rotary axis so that the angle defined therebetween is equal to the sum of an integral multiple of 2 pi Divided by by the number of permanent magnets in each group and pi Divided by by the number of permanent magnets in each group.

Claim 16

A brushless direct current motor comprising a rotor rotatable about a rotary axis and carrying magnetic circuit means said magnetic circuit means of said rotor including first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group; a flat stator pole positioned within said gap and having driving coil means and magnetic sensitive element means mounted thereon in said gap to thereby be within said magnetic field, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal, said motor having at least two magnetic sensitive element means and at least two driving coils controlled by each of said magnetic sensitive element means, said magnetic sensitive element means being positioned about said rotary axis so that the angle defined therebetween is equal to the sum of an integral multiple of 2 pi Divided by by the number of permanent magnets in each group and pi Divided by by the number of permanent magnets in each group.

Claim 17

A brushless direct current motor comprising a rotor rotatable about a rotary Axis and carrying magnetic circuit means said magnetic circuit means of said rotor includes first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group, half of the permanent magnets of each group extend radially beyond the other permanent magnets of said group, said first-mentioned half of said permanent magnets of respective groups being in facing relation and arranged alternately within the group with the permanent magnets of lesser radial dimension, said magnetic sensitive element means including magneto resistive element means positioned within the locus of said permanent magnets of greater radial dimensions but outside of the locus of said permanent magnets of lesser radial dimension, a flat stator plate positioned within said gap and having driving coil means and magneto resistive element means mounted thereon in said gap to thereby be within said magnetic field, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 18

A brushless direct current motor comprising a rotor rotatable about a rotary Axis and carrying magnetic circuit means said magnetic circuit means of said rotor includes first and second groups of essentially pie-shaped permanent magnets mounted in spaced relation to define a gap, through which a magnetic field flows in a direction substantially parallel to said rotary axis, the permanent magnets of each group being distributed circumferentially about said rotary axis and being polarized along an axis extending substantially parallel to said rotary axis, each adjacent pair of permanent magnets in each group being of opposite polarity, the poles of the permanent magnets of said first group being of opposite polarity to the facing poles of the permanent magnets of said second group, half of the permanent magnets of each group extend radially beyond the other permanent magnets of said group, said first-mentioned half of said permanent magnets of respective groups being in facing relation and arranged alternately within the group with the permanent magnets of lesser radial dimension, said magnetic sensitive element means including magneto resistive element means positioned within the locus of said permanent magnets of greater radial dimensions but outside of the locus of said permanent magnets of lesser radial dimension, a flat stator plate positioned within said gap and having driving coil means and magneto resistive element means mounted thereon in said gap to thereby be within said magnetic field, said magnetic sensitive element being adapted to detect the condition of said magnetic field when said rotor is still and moving to produce a detecting signal in response thereto; and circuit means interconnecting said driving means and magnetic sensitive element means for applying a driving current to said driving coil means in response to said detecting signal.

Claim 19

A brushless direct current motor as recited in claim 11, including at least two magnetic reluctance elements and at least two driving coils, said circuit means interconnecting each of said driving coils with one of said magnetic reluctance elements for the control thereof.