Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1980-12-12
1983-06-07
Duggan, Donovan F.
Electrical generator or motor structure
Dynamoelectric
Rotary
310268, H02K 3700
Patent
active
043873120
DESCRIPTION:
BRIEF SUMMARY
The subject of the present invention is a polyphase stepping motor for direct driving of the seconds' or minutes' axis of a time piece movement, comprising a disc-shaped rotor which is magnetized so as to exhibit on at least one of its surfaces 2 N alternately positive and negative poles, and comprising at least two stator elements including each a magnetic circuit of magnetically permeable material with an air gap in which the rotor poles are moving, and including each at least one coil coupled with the magnetic circuit and fed by a periodic control current, the arrangement being such that the number of steps P made per control current period is 60 m
, m=1, 2, 3, . . . .
In electronic time piece movements, in particular in quartz clocks, the noise generated by the intermediate movable parts between the rotor of the motor and the seconds' or minutes' axis and by the intermittent contacts between the teeth of the various gear pairs is comparatively loud and is a nuisance. It is therefore desired to have a motor capable of directly driving the seconds' or minutes' axis to provide a more silient mechanism.
The object of the present invention is therefore to provide a motor with m.60 steps per rotor turn, which is of a specially simple and reliable structure. The invention also aims to reduce the manufacturing cost of the motor taking into account, in particular, the required control circuit and the manufacturing margins in mass-production.
The attached drawing shows, by way of example, various embodiments of a stepping motor according to the invention, and the advantages and characteristic features of the invention will become clearly apparent from the description given hereafter with reference to these various embodiments.
In the drawing:
FIG. 1 is a partial top view of a three-phase homopolar motor according to the invention,
FIG. 2 is a section along broken line II--II of the motor of FIG. 1,
FIG. 3 is a partial top view of a two-phase heteropolar motor according to the invention,
FIG. 4 is a section along broken line IV--IV of the motor of FIG. 3,
FIG. 5 is a top view of a two-phase homopolar motor according to the invention,
FIG. 6 is a section alone broken line VI--VI of the motor of FIG. 5,
FIG. 7 is a partial top view of the motor of FIG. 5 showing the magnetisation of the rotor,
FIG. 8 is a sectional view similar to that of FIGS. 2 and 6 of an alternative embodiment of a homopolar polyphase motor according to the invention, and
FIG. 9 is a partial sectional view of a motor according to the invention in which each stator element comprises two U-shaped parts.
The preferred embodiments described by way of example, are based on the following considerations. The realization of rotors in the form of multipolar magnets with N pairs of poles for use in time piece movements is in practice limited to maximum values of N=15. The polyphase control of the stator element coils allows to obtain P steps per electric period so that the motor makes N.multidot.P steps per turn. As the number of coils as well as the number of transistors of the output stage of the control circuit and its number of terminals is related to P, it is advantageous to make P small. Furthermore, when choosing a unipolar or bipolar control (pulses of same polarity or of alternating polarity) it is to be considered that bipolar controls require four transistors and two insulated wires per coil contrary to one transistor or even two transistors and one insulated wire per coil controlled by unipolar pulses. Under these circumstances, the preferred solution for a motor making 60 steps per complete revolution of the rotor are the following: control control with mid-point coils.
It is to be noted that solutions 2, 3, and 5 require four, three and four transistors, respectively, without taking into account as much possible damping transistors to short-circuit the unfed coils on themselves. If damping transistors are used, solutions 1 and 4 are more advisable than solutions 2 and 5 which use only one half of a coil at a time, at an equal total number
REFERENCES:
patent: 3803433 (1974-04-01), Ingenito
Duggan Donovan F.
Portescap
LandOfFree
Stepping polyphased motor for a clockwork mechanism does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stepping polyphased motor for a clockwork mechanism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stepping polyphased motor for a clockwork mechanism will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2344850