Electricity: motive power systems – Synchronous motor systems
Reexamination Certificate
2001-04-20
2002-07-09
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Synchronous motor systems
C318S567000, C318S034000, C318S041000, C388S805000
Reexamination Certificate
active
06417643
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a synchronous control device used in processing systems for stretching resins and metals, conveyors and rotary presses. The present invention particularly relates to a synchronous control device which provides an origin matching operation in order to synchronously drive rotational phase and rotational frequency of electric motors in a master section and plural slave sections as well as synchronously drive the rotational phase and the rotational frequency of each machine shaft driven by said electric motors.
2. Description of the Related Art
FIGS.
23
(
a
), (
b
) illustrate an example of a conventional rotary press with shafts. FIG.
23
(
a
) illustrates a driving system of the conventional rotary press and is comprised of the following components, a main shaft
100
, an electric motor
101
, a sub shaft
102
, a transmitter or a deceleration device
103
, a paper feeding part
104
, a printing part
105
, color printing parts of yellow
106
, cyan
107
, magenta
105
and black
109
, running paper
110
, and a folding part
111
.
In FIG.
23
(
a
) each running paper
110
from the paper feeding part
104
is printed in the printing parts
105
~
106
and gathered to be folded in the folding part. Here, in the conventional rotary press, the printing parts
105
~
109
and the folding part
111
are mechanically combined and synchronously driven with the main shaft
100
and the sub shaft
102
which are driven by the plural electric motors.
FIG.
23
(
b
) diagrams a model of the printing part
105
~
109
, in which ink is supplied from an ink roller
105
a
to an image part of a lithographic plate which is wound on a plate cylinder
105
b
. The ink which is supplied to the image part of a lithographic plate is transferred to a face on a blanket cylinder
105
c
, then it is printed on the paper
105
d
. The printing position of each paper should be precisely accorded in the folding part
111
. Since the printing parts
106
~
109
conduct color print, the printing position in the color printing parts
106
~
109
especially should be accorded each other with high accuracy because a shear of only 20~30 &mgr;m in printing produces visual color misalignment.
According to the present invention, as plural electric motors can be synchronously controlled with high precision, a shaft-less rotary press can be realized in place of the conventional rotary press driven with shafts.
A master electric motor, a slave electric motor and a conventional synchronous control device driven by these electric motors are shown in the following.
FIG. 24
illustrates an example of a conventional synchronous control device for plural electric motors. For simplicity, this diagram is comprised of a master section and one slave section.
In
FIG. 24
,
0
is a master section,
1
is a slave section,
01
is a rotational frequency setting device, Cm is a master control device,
11
is a rotational frequency detector,
12
is a rotational frequency feedback detector,
13
is a gain amplifier, Am is a master driving device, Im is a master electric motor, Rm is a master rotary encoder, Km is a shaft of the master machine, Cs
1
is a slave control device,
21
,
23
,
26
and
28
are receiving interfaces,
22
is a rotational frequency detector,
24
is a rotational frequency feedback detector,
25
is a gain amplifier,
27
is a phase detector of the master electric motor,
29
is a phase detector of the slave electric motor,
30
is a phase deviation detector for the electric motors,
31
is a gain amplifier,
40
is a switch for a synchronous control, As
1
is a slave driving device, Is
1
is a slave electric motor, Rs
1
is a slave rotary encoder and Ks
1
is a shaft of the slave machine.
The master rotary encoder Rm and the slave rotary encoder Rs
1
output A phase pulse and B phase pulse in proportion to the rotation and output Z phase pulse per each rotation.
In
FIG. 24
, a signal from the rotational frequency setting device
01
is sent to the rotational frequency detector
11
of the control device Cm of the master section. The rotational frequency feedback detector
12
detects rotational frequency feedback according to the A phase signal and the B phase signal outputted from the master rotary encoder Rm attached to the master electric motor Im.
The output signals from the rotational frequency detector
11
and the rotational frequency feedback detector
12
are calculated and sent to the master driving device Am through the gain amplifier
13
. The master driving device Am then drives the master electric motor Im by controlling rotational frequency, and the shaft Km of the master machine is driven.
The A phase signal and B phase signal from the master rotary encoder Rm are also sent to the rotational frequency setting detector
22
through the receiving interface
21
of the slave control device Cs
1
so as to detect a setting rotational frequency of the slave section
1
. Addition, A phase signal and B phase signals outputted from the slave rotary encoder Rs
1
attached to the slave electric motor are sent to the rotational frequency feedback detector
24
through the receiving interface
23
of the slave control device Cs
1
in order to detect a rotational frequency feedback. The output signals from the rotational frequency detector
22
and the rotational frequency feedback detector
24
are calculated and sent to the slave driving device As
1
through the gain amplifier
25
. The slave driving device As
1
drives the slave electric motor Is
1
so as to tune the master electric motor Im and the shaft Km of the master machine and the shaft Ks
1
of the slave machine are driven in tune.
Furthermore, the phase detector
27
of the master electric motor in the slave control device Cs
1
counts the A phase pulse and B phase pulse outputted by the rotation of the master electric motor Im through the receiving interface
21
and clears the phase detector
27
by Z phase signal outputted by each rotation of the master electric motor Im through the receiving interface
26
. The phase detector
27
of the master electric motor constantly detects the rotational phase of the master electric motor and that of the shaft of the master machine with the number of pulses.
In the same manner, the phase detector
29
of the slave electric motor counts up the A phase pulse and B phase pulse outputted by the rotation of the slave electric motor Is
1
through the receiving interface
23
, and clears them by Z phase signal outputted by each rotation of the slave electric motor Is
1
, through the receiving interface
28
. The phase detector
29
of the slave electric motor constantly detects rotational phase of the slave electric motor and the shaft of the slave machine with number of pulses.
Then the output of the phase detector
27
of the master electric motor and the phase detector
29
of the slave electric motor are inputted to the phase deviation detector
30
so as to calculate the phase deviation and output it. The phase deviation goes through the gain amplifier
31
and switch
40
, which is closed when synchronous control is ON, and it is added to or subtracted from the output of the rotational frequency detector
22
as correction, then the synchronous control is performed.
Here, referring to
FIG. 26
, the phase deviation outputted from the phase deviation detector
30
according to the prior art is explained.
In
FIG. 26
, X axis shows difference of the rotational number between the master electric motor Im and the slave electric motor Is
1
, Y axis shows a phase deviation, which is outputted from the phase deviation detector
30
, converted to angle. In
FIG. 26-A
, a circle (a) shows the modeled shaft Km of the master machine, a line z
1
shows projection of Z phase position of the master rotary encoder Rm on the circle (a). In this invention, counterclockwise direction is defined as an ordinary direction of the electric motors, that is, from the center of the circle (a), which shows the shaft of the master machine Km, plus
Akiyama Toru
Fujita Masakatsu
Hisada Hiroyuki
Kotani Ikuo
Shiba Noriyuki
Bierman, Muserlian and Lucas
Kabushiki Kaisya Tokyo Kikai Seisakusho
Leykin Rita
Nappi Robert E.
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