Metal working – Means to assemble or disassemble – Means to assemble electrical device
Reexamination Certificate
2001-12-21
2004-06-15
Chang, Richard (Department: 3729)
Metal working
Means to assemble or disassemble
Means to assemble electrical device
C029S739000, C029S741000, C029S743000, C029S721000, C029S759000, C029SDIG004, C029S832000, C029S833000, C901S040000, C414S737000, C414S751100, C414S752100, C294S064200
Reexamination Certificate
active
06748649
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a component holding head for use, e.g., in mounting electronic components on electronic circuit boards, a component mounting apparatus equipped with the component holding head, and a component hold method carried out by the component mounting apparatus.
2. Background Art
A component suction head part set in a component mounting apparatus adapted to automatically mount electronic components onto electronic circuit boards has nozzles to suck and mount the electronic components to the electronic circuit boards. Lately, precise control of the nozzles coming into contact with electronic components during sucking and mounting of the electronic components is considered as one of factors to improve quality of the electronic circuit boards to be produced. An example of the conventional electronic component mounting apparatus will be described with reference to FIG.
4
.
FIG. 4
shows a component suction head part
101
including the aforementioned nozzles, a sucking device
103
for sucking the electronic components with the use of the nozzles, an X-Y robot
102
moving the head part
101
in X, Y directions, and a control device
104
controlling operations of the head part
101
, the X-Y robot
102
, and the sucking device
103
in the conventional electronic component mounting apparatus. The head part
101
is constructed as will be described below. Only essential parts constituting the head part
101
are indicated in
FIG. 4 and
, for instance, a body part of the head part
101
and the like are not illustrated. Reference numeral
135
in
FIG. 4
is a spline shaft which has a nozzle
136
set at one end part
135
a
for sucking an electronic component
138
through a suction action, and a rotation receiver
143
at the other end part
135
b
. The suction action is conducted by the sucking device
103
, whereby the air is guided into the sucking device
103
through the nozzle
136
and the spline shaft
135
. Two nuts
131
,
134
are fitted to the spline shaft
135
in an axial direction of the spline shaft
135
to make the spline shaft
135
slidable in the axial direction. These nuts
131
,
134
are held to the body part (not shown) of the head part
101
via respective bearings
132
,
133
. The spline shaft
135
is accordingly rendered movable in the axial direction and rotatable in a circumferential direction relative to the body part.
The rotation in the circumferential direction of the spline shaft
135
is achieved by a motor
142
. Specifically, a pulley
139
rotating along with the spline shaft
135
is fitted to the spline shaft
135
. The spline shaft
135
is movable in the axial direction relative to the pulley
139
. A pulley
141
is attached to a driving shaft of the motor
142
and is coupled to the pulley
139
via a belt
140
. When the motor
142
rotates the pulley
141
, the spline shaft
135
is accordingly rotated in the circumferential direction via the belt
140
and the pulley
139
.
Meanwhile, the movement in the axial direction of the spline shaft
135
is caused by a motor
149
. More specifically, a nut
146
, whereat a lever
147
projects, is meshed with a ball screw
145
connected to a driving shaft of the motor
149
via a coupling
148
. A roller
144
at a leading end of the lever
147
is engaged with a groove
143
a
formed in the rotation receiver
143
. When the ball screw
145
is rotated by the motor
149
, the lever
147
moves in the axial direction while the roller
144
is engaged with the rotation receiver
143
, thereby moving the spline shaft
135
in the axial direction.
The conventional component mounting apparatus of the above constitution operates in the following manner.
When the X-Y robot
102
operates under the control of the control device
104
, the head part
101
is moved to a component suction position where the electronic component is to be sucked. The motor
149
is driven under the control of the control device
104
, thereby lowering the spline shaft
135
and the nozzle
136
. At the same time, the sucking device
103
is driven to make the nozzle
136
suck the electronic component. Subsequently, the ball screw
145
is rotated backward by the motor
149
to raise the nozzle
136
. In order to correct a mount direction of the sucked electronic component, the motor
142
is driven through the control action of the control device
104
to rotate the nozzle
136
to a proper position. The X-Y robot is driven again to move the head part
101
to a component mount position above the electronic circuit board, and then the motor
149
is driven to lower the nozzle
136
. The electronic component
138
is thus mounted on the electronic circuit board.
The above-described constitution of the conventional component mounting apparatus has drawbacks, though.
In these days, the component mounting apparatus is adapted to handle not only electronic components, in which silicon substrates having electronic circuits formed thereon are sealed with resin material, but bare ICs and the like. In the case of bare ICs, a mount pressure by the nozzle
136
to the bare ICs at the time of mounting is required to be controlled to prevent damage to the bare ICs. Therefore, the component mounting apparatus is constituted to correctly manage a position of the nozzle
136
relative to the bare ICs in X, Y directions, and also to manage the pressure of the nozzle
136
on the bare ICs on the basis of a torque of the motor
149
moving the nozzle
136
up and down. Although a sensor is preferred to be directly installed at the nozzle
136
in the component mounting apparatus to correctly measure the position of the nozzle
136
in the X, Y directions and an up-down direction, it is impossible to set the sensor to the spline shaft which moves in the axial direction and the circumferential direction as described above. As such, the position of the nozzle
136
in the up-down direction is actually controlled on the basis of output information from a rotary encoder
150
incorporated in the motor
149
.
On the other hand, the position of the spline shaft
135
in the axial direction is hard to correctly grasp, because the movement of the spline shaft
135
in the axial direction is carried out via the rotation receiver
143
and the roller
144
, etc., which is dependent on movement accuracy of the ball screw
145
in the axial direction. Moreover, the rotation receiver
143
and the roller
144
, etc. are formed of non-rigid material. Under the circumstances, the conventional electronic component mounting apparatus finds difficulty in accurate control of the movement of a leading end of the nozzle, resulting in an impediment to improvement of mount quality.
The present invention is devised to solve the aforementioned drawbacks and has for its object to provide a component holding head, a component mounting apparatus equipped with the component holding head, and a component hold method executed by the component mounting apparatus, which can improve mount quality of components to articles to which the components are to be mounted.
SUMMARY OF THE INVENTION
In accomplishing this and other objects, the present invention is constituted as described below.
According to a first aspect of the present invention, there is provided a component holding head equipped with a shaft which has a nozzle, for holding a component, set at one end part of the shaft and is driven in an axial direction thereof A magnet is fixed to a circumferential face of the shaft and a coil is disposed around the magnet, thereby constituting a voice coil motor for driving the shaft in the axial direction, so that movement of the shaft in the axial direction is controlled through control of power supply to the voice coil motor.
According to a second aspect of the present invention, there is provided a component holding head according to the first aspect, further comprising a detecting device which is installed at the shaft for detecting the movement of the shaft in the axial direction, so that an amou
Kabeshita Akira
Okuda Osamu
Shida Satoshi
Sueki Makoto
Chang Richard
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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