Tubular motor, control method for brushless motor, and motor equipped with brake

Patent metadata

Field	Value
Publication number	US-10298093-B2
Application number	US-201515312300-A
Country	US
Kind code	B2
Filing date	Oct 2, 2015
Priority date	Oct 7, 2014
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A tubular motor may include a tubular case, a motor unit provided inside the case, and a first planetary gear unit placed inside the case at an output side in the motor shaft direction with respect to the motor unit. On the motor unit, a concave part may be formed in an output side end surface of an output side end plate section that supports a rotor, at an output side of the rotor. On the first planetary gear unit, a planetary carrier may include a supporting plate that overlaps with planetary gears at an counter-output side in order to support the planetary gears from the counter-output side. The first planetary gear unit may be immediately adjacent to the output side end plate section at an output side.

First claim

What is claimed is:

1. A tubular motor comprising:
a tubular case that stretches in a motor shaft direction;
a motor unit provided inside the case; and
a first planetary gear unit placed inside the case at an output side in the motor shaft direction with respect to the motor unit;
wherein, in the motor unit, a concave part, being recessed toward a counter-output side, is formed in an output side end surface of an output side end plate section that supports a rotor, in such a way as to be rotatable, at an output side of the rotor;
in the first planetary gear unit, a planetary carrier comprises a supporting plate that overlaps with planetary gears at an counter-output side in order to support the planetary gears from the counter-output side; and
the first planetary gear unit is immediately adjacent to the output side end plate section at an output side;
wherein, the first planetary gear unit comprises a cylindrical member in which an internal gear is formed on an internal surface, and a counter-output side end section of the cylindrical member contacts the output side end plate section;
wherein, the output side end plate section comprises an inner circumferential ring convex part protruding toward an output side from the output side end surface; and an outer circumferential ring convex part protruding toward an output side from the output side end surface, the outer circumferential ring convex part being positioned at an outer side of the inner circumferential ring convex part in a radial direction; and
a space between the inner circumferential ring convex part and the outer circumferential ring convex part form the concave part;
wherein, at the counter-output side end section of the cylindrical member, a step part is circularly formed, where an inner diameter of a section located at a counter-output side is larger than an inner diameter of a part having the internal gear formed there; and
at the step part, a first part facing a counter-output side contacts the outer circumferential ring convex part from an output side; and at the step part, a second part facing inside in a radial direction contacts the outer circumferential ring convex part from an outside in a radial direction.

2. The tubular motor according to claim 1 ;
wherein, inside the cylindrical member, a second planetary gear unit is placed at an output side of the first planetary gear unit; and
in the second planetary gear unit, a planetary carrier comprises a supporting plate that overlaps with planetary gears at an counter-output side in order to support the planetary gears from a counter-output side.

3. The tubular motor according to claim 2 ;
wherein, inside the cylindrical member, a third planetary gear unit is placed at an output side of the second planetary gear unit; and
in the third planetary gear unit, a planetary carrier comprises a supporting plate that overlaps with planetary gears at an counter-output side in order to support the planetary gears from a counter-output side.

4. The tubular motor according to claim 3 ;
wherein, all of an internal gear of the first planetary gear unit, an internal gear of the second planetary gear unit, and an internal gear of the third planetary gear unit are formed on the internal surface of the cylindrical member.

5. The tubular motor according to claim 4 ;
wherein, inner diameters of the cylindrical member become larger step by step from an output side toward a counter-output side.

6. The tubular motor according to claim 1 ;
wherein, a brake unit is provided inside the case, the brake unit being structured to apply a brake on the rotor of the motor unit at a position adjacent to a counter-output side of the motor unit.

7. A control method for a brushless motor including a rotor comprising a rotor magnet, a stator having a plurality of drive coils, and magnetic sensor elements for creating a position detecting signal corresponding to a turning motion of the rotor magnet; the control method comprising:
carrying out a turning detection process in order to detect a turn of the rotor, on the basis of a detection result by the magnetic sensor elements, before starting to supply the drive coils with electricity, in a first direction driving process for driving the rotor to turn in a first direction, wherein a load for turning in the first direction being externally applied to the rotor;
supplying the plurality of drive coils with a drive current for driving the rotor to turn in the first direction, in the case where a turning speed of the rotor is less than a threshold, according to a detection result of the turning detection process; and
applying a braking force to the rotor, in the case where the turning speed of the rotor is equal to or higher than the threshold;
wherein, the braking force is generated by way of short-circuiting both terminals of at least one drive coil out of the plurality of drive coils.

8. The control method for a brushless motor according to claim 7
wherein, at a time of applying the braking force to the rotor, a comparison is made between a commanded speed for driving the rotor to turn in the first direction, and a turning speed of the rotor detected by the magnetic sensor elements, in order to change a level of the braking force, on the basis of a comparison result between the commanded speed and the turning speed.

9. The control method for a brushless motor according to claim 7 ;
wherein, in a second direction driving process for driving the rotor to turn in a second direction, being opposite to the first direction, without the turning detection process, the plurality of drive coils are supplied with a drive current for driving the rotor to turn in the second direction.

10. The control method for a brushless motor according to claim 7 ;
wherein, after supplying the plurality of drive coils with the drive current, a turn of the rotor is detected on the basis of the detection result by the magnetic sensor elements; and
if the turning speed of the rotor is lower than a specified speed value, the drive current is increased; and
in the meantime, if the turning speed of the rotor is lower than a specified speed value, the drive current is decreased.

11. The control method for a brushless motor according to claim 7 ;
wherein, the rotor is connected to a turning shaft for winding a shutter, by the intermediary of a series of speed-reduction gears.

12. A motor equipped with a brake comprising:
a motor unit comprising a motor shaft that is rotatable around an axis line; and
a brake unit structured to apply a braking force to the motor shaft;
wherein, the brake unit comprises:
a disc-like first plate that turns together with the motor shaft;
a second plate that faces the first plate in a shaft direction;
a cylindrical holder placed around the second plate;
a turning prevention mechanism structured to prevent the second plate from turning around the axis line; and
a plate drive mechanism structured to drive the second plate to one direction for making the first plate and the second plate contact with each other as well as to the other direction for making the first plate and the second plate draw apart from each other; and
the second plate comprises: a plate part that faces the first plate, and a convex part that protrudes from the plate part toward a counter side being opposite to the first plate; and
the turning prevention mechanism is structure to prevent the second plate from turning, between the convex part and the cylindrical holder; and
at a time when the plate drive mechanism has the first plate and the second plate contact with each other, the first plate and the second plate contact with each other

Assignees

• Nidec Sankyo Corp

Inventors

• Ando Masaaki
• Yoshikawa Shinichi
• Nakamura Goro
• Kurosawa Hironori
• Akuzawa Yuu
• Takeda Tadashi
• Ashibe Noburu

Classifications

• H02K7/1163

  where at least two gears have non-parallel axes without having orbital motion · CPC title

• F16D55/36

  Brakes with a plurality of rotating discs all lying side by side · CPC title

• H02P6/24

  Arrangements for stopping · CPC title

• H02K7/116 Primary

  with gears · CPC title

• H02P3/22

  by short-circuit or resistive braking · CPC title