SANYO DENKI Technical Report No.5 May 1998
Feature
Development of New Type Wire Winding Machines
"Inner Wire Winding Machine" and
"Work Rotation Type Wire Winding Machine"
Yutaka Takeuchi Ooki Hiroshi
1. Introduction
Remarkable advances in reducing the size and weight of motors including AC servo
motors have been made in recent years, assisted by improvements in wire winding
technology. As we face performance and price competition, a key target is to
develop better wire winding technology and improve the productivity.
Efforts to improve wire winding technology have focused on better wire alignment
degree and higher space factor. The key to better motor performance is how to
improve these two aspects at the same time.
With this background, the Production Technology Development Department has
developed two models of a new, innovative composite actuator (linear
motion/rotary motor and linear motion stepping motor). Using these actuators, we
have developed a new inner type (wires are wound directly around the laminated
core) wire winding machine.
We have also developed a work rotation type wire winding machine that winds
wires (magnet wire) while pressing the wire to bend it until it forms a curve shaped
like the divided core. Our "S-MAC" controller is installed in the work rotation type
wire winding machine. This paper reports on these two models of new wire winding
machine including the composite actuator. The control of the work rotation type
wire winding machine that is described in chapter 5 is described in a separate report
entitled "Application of "S-MAC" TYPE C (Development of Work Rotation Type
Wire Winding Machine)" in this issue.
2. Background of Development
With market demand increasing for the compact and medium size "P3" and "P5"
AC servo motors that are the main product line of Sanyo Denki, we decided to
introduce the wire winding machine. Wire winding machines are also needed
following the development of the 30 kW class large-capacity servo motor, which is
based on the existing large-size "P6" and "P8" servo motors. A wire winding
machine having good wire alignment degree and high productivity is required. The
large-capacity servo motor uses thick wire of up to 3.0 mm diameter that makes
winding difficult due to the rigidity of the wire.
3. Wire Alignment Degree and Space Factor
Before describing this development in detail, we describe the alignment degree and
space factor which are very important factors in wire winding technology as
mentioned at the beginning of this report.
The alignment degree indicates how closely the wires are brought into contact in
close alignment with the shape of the laminated core when the wires are wound
around the laminated core. The space factor is the ratio of the total cross-section of
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the wound wires to the spatial area of the core.
Fig. 1 and Fig. 2 show front and rear views of the laminated core around which the
wires are wound with the ideal winding method having good wire alignment degree.
The wires are wound across each other as shown in Fig. 2, which is essential to
achieve good wire alignment degree.
Also, the better the alignment degree, the higher space factor achieved.
4. Development of New Type Inner Wire Winding Machine
4.1 Features of the Wire Winding Machine
In the inner type wire winding machine that is developed for the "P3" and "P5" AC
servo motors, the nozzle has a box-shaped movement (linear forward + rotation in
forward direction + linear backward + rotation in reverse direction), and a linear
motion/rotary motor (AC servo motor) is used as the power source of these motions.
The linear motion/rotary motor (AC servo motor) can control both the linear motion
and rotation as desired. The linear and rotary motions of the nozzle can be
controlled as desired while winding the wires with the linear motion/rotary motor,
and the deflection angle and stroke of the nozzle can be changed at will in the new
wire winding machine.
The new type inner wire winding machine has the following features:
(1) Highly-aligned wire winding is achieved by changing the nozzle stroke during
winding.
(2) Operation and setup performance are improved; the deflection and stroke of the
nozzle, as well as model switchover, can be done by single touch panel operations.
(3) Ideal crossover of wires is achieved by the linear motion stepping motor and
servo controlled indexes.
(4) The simple mechanism generates good linear motion.
(5) The winding time of the nozzle triplet is shorter,improving productivity (200%
better than conventional equivalent).
Fig. 3 New type inner wire winding machine
4.2 Linear Motion/Rotary Motor
The linear motion/rotary motor as shown in
Fig. 4 is the main part of the "P6" and
"P8" AC servo motors. This AC servo motor has two pairs of stator and rotor in one
housing that are controlled by independent encoders.
The linear motion/rotary motor has two hollow shafts as shown
Fig. 5. The spline
nuts and ball screws are attached to each hollow shaft. Rotation of the front rotor
revolves the output shaft (spline shaft), while rotation of the rear rotor revolves the
ball screw nut. At this moment, rotation of the ball screw is withheld, and its
rotation is converted to linear motion that is then transmitted to the output shaft.
With this structure, the dual-axes drive of rotation and linear motion is achieved.
The linear motion/rotary motor shown in Fig. 5 has the maximum stroke of 250 mm
with linear motion of thrust force of about 2.6 kN (rated). The resolution per pulse is
0.036
in the rotary direction and 0.002 mm in the linear motion.
4.3 Linear Motion Stepping Motor
The linear motion stepping motor is developed on the basis of the "89 steps,
five-phase" series stepping motor. It has a ball screw spline inside the hollow motor
shaft as shown in
Fig. 6. The nuts of the ball screw spline include the ball screw nut
in the front and the spline nut in the rear. Rotation of rotor is caught by the spline
and the shaft moves in the linear motion with the stroke of 200 mm. The linear
motion stepping motor that is used in the wire winding machine develops thrust
force of about 2.5 kN with the resolution of 0.016 mm/p.
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