Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
1998-12-04
2001-06-05
Horabik, Michael (Department: 2635)
Communications: electrical
Continuously variable indicating
With meter reading
C340S870310, C340S870350, C324S207110, C324S207180, C324S207250, C318S661000
Reexamination Certificate
active
06243023
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Present Invention
The present invention relates to an encoder used for various motors and a parameter establishing device capable of establishing various bits of parameter information for the encoder from the outside of the encoder.
b) Description of the Related Art
As shown in
FIG. 8
, a conventional servo motor comprises, for example, brushless motor
41
, encoder
45
, which separately detects data on a rotational position of brushless motor
41
and data on an absolute position of the motor's magnetic poles, and control device
42
which controls the driving of brushless motor
41
according to a detection signal from encoder
45
. Also, cables are used for transmission of signals between encoder
45
and control device
42
.
Encoder
45
is stored in case
50
as shown in
FIG. 8
(indicated with a dotted line to avoid making the figure busy) wherein disc-shaped pole detecting magnet
46
is formed at the end of main shaft
41
a of brushless motor
41
. Pole detecting magnet
46
transmits driving position data in association with U, V and W phases; also, it is magnetized in such a way that N and S poles, which are equivalent of magnetic poles of brushless motor
41
, alternate around the circumference. In addition, drum-shaped magnetic recording medium
47
is formed between pole detecting magnet
46
and brushless motor
41
. Magnetic recording medium
47
transmits rotational position data in association with Z, A and B phases; also, it consists of an upper portion, which is magnetized in such a way that a pair of N and S poles is positioned adjacent to each other at a position on the circumference, and a lower portion which is magnetized in such a way that N and S poles alternate around the circumference.
Furthermore, a plurality of Hall devices
45
a
and MR sensor
45
b
are positioned across from the magnetized areas of pole detecting magnet
46
and magnetic recording medium
47
, respectively. Hall devices
45
a
are mounted on the reverse side of signal processor base
17
on which an encoder internal signal processor circuit is formed.
Hall devices
45
a
and MR sensor
45
b
generate pulses caused by rotation of brushless motor
41
. Also, encoder
45
and control device
42
are connected to each other via cables such that control device
42
controls the driving of brushless motor
41
by using pulses from encoder
45
.
In this case, brushless motor
41
can be of various modes; for example, ones with 50 W, 100 W to 1.1 kW and ones having two pairs or one pair of N and S poles of magnets. Also, depending on the use, encoder
45
itself can be such that 500 pulses or 1,000 pulses per rotation can be generated. Therefore, various combinations of brushless motor
41
and encoder
45
are possible.
However, conventional encoder
45
does not have a function to determine what kind of encoder shall be used according to kind of the brushless motor, that is, a self-diagnosing function. Hence, various parameters must be established during manufacturing of the encoder. Examples of such various bits of parameter information include the number of magnetic poles of brushless motor
41
, the code indicating intensity of brushless motor
41
in watts, an identification number (ID) of encoder
45
, codes indicating the manufacturing number, model, manufacturer and manufacturing date of encoder
45
, codes assigning the number pulses per rotation in association with A and B phases of encoder
45
, and a transmission format. The above various bits of parameter information are established on signal processor base
17
by a short pin or a dip switch; after the information is established, the cover of case
50
is closed.
Nonetheless, transmission of signals from encoder
45
and control device
42
in the above conventional servo motor is one-way transmission in which only output from encoder
45
to control device
42
is constantly generated. As a result, once the cover of case
50
of encoder
45
is closed after various bits of parameter information are established, the information in encoder
45
cannot be changed. Therefore, if there is a mistake in the selection of signal processor base
17
in encoder
45
or a mistake in the established parameter information, replacement of signal processor base
17
and reestablishment of the mistaken parameter information must be carried out by reopening the cover. This causes undesirable operations such that the cost of the servo motor is increased.
OBJECT AND SUMMARY OF THE INVENTION
Therefore, the present invention has, as its primary object, to provide an encoder in which various bits of parameter information in the encoder can be reestablished by electric operation from outside of the encoder while the cover of the encoder is closed and to provide a parameter establishing device in which various bits of parameter information of the encoder can be established from outside of the encoder.
In accordance with the invention, an encoder comprises position detecting means for detecting a magnetic pole position and a rotational position of a motor. The encoder also includes a memory portion for storing parameter information particular to the motor or the position detecting means. A transmitting portion of the encoder is provided for externally transmitting parameter information particular to the position detecting means as a differential signal. Transmission suspension request detecting means are provided for detecting that the differential signal is driven by a given signal externally provided such that the differential signal does not exist as a transmission signal and for generating a transmission suspension request signal requesting suspension of transmission of the differential signal. Finally, switching control means are provided for switching the transmitting portion to a transmission suspending condition based on the transmission suspension request signal provided by the transmission suspension request detecting means.
REFERENCES:
patent: 4646088 (1987-02-01), Inoue
patent: 4707695 (1987-11-01), Takahashi et al.
patent: 4764767 (1988-08-01), Ichikawa
patent: 4779075 (1988-10-01), Zagelein et al.
patent: 4855734 (1989-08-01), Elsdoerfer
patent: 5254919 (1993-10-01), Bridges et al.
patent: 5625353 (1997-04-01), Kitagiri et al.
patent: 5815089 (1998-09-01), Katagiri et al.
Edwards, Jr. Timothy
Horabik Michael
Reed Smith LLP
Sankyo Seiki Mfg. Co. Ltd.
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