Apparatus for auomatically press-fitting a turntable

An apparatus for automatically press-fitting a turntable has driving motor attachably/detachably installed to/from a driving motor fixing part. A turntable assembly fixing part is attachably/detachably installed with a turntable assembly and arranged to allow a rotating shaft of the turntable assembly to be exactly coaxial with a motor shaft of the driving motor. An insertion lug is formed at a lower surface of the turntable assembly fixing part to be fitted/separated into/from a groove in an upper corresponding surface of a turntable. A motor shaft fixing part arranged to an upper portion of a drive chassis coupled to the driving motor includes a stand portion formed with an elongated guide hole for receiving/separating the motor shaft and a motor shaft supporting portion which has a sidewall upwardly bent to perpendicularly extend from an edge of the elongated guide hole of the stand portion. The motor shaft supporting part grips to fix around the motor shaft while press-fitting the motor shaft into the turntable assembly to prevent warpage of the motor shaft caused by the press-fitting force in the axial direction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for automatically 
press-fitting a turntable, and more particularly to an apparatus for 
automatically press-fitting a turntable capable of minimizing an eccentric 
error by inserting a rotating shaft of a driving motor into a turntable 
assembly with significantly high precision. 
2. Description of the Prior Art 
Generally, an appliance such as optical video disc players, digital audio 
disc players and compact disc players is an apparatus for performing 
recording or reproducing operation with respect to a disc capable of 
magnetic recording or optical recording. In these appliances, the disc 
containing various audio signals or video signals is mounted to a 
turntable assembly of a corresponding disc player, and then the 
information is reproduced while rotating the disc by using the turntable 
assembly. U.S. Pat. Nos. 5,228,023 and 4,771,971 disclose examples of a 
construction and manufacturing method of the conventional turntable 
assembly. 
The conventional turntable assembly will be described with reference to 
FIGS. 1 and 2 below. 
FIG. 1 is an exploded perspective view showing the conventional turntable 
assembly, and FIG. 2 is a sectional view showing a joining state that the 
conventional turntable assembly is press-fitted into a driving motor. 
Here, a reference numeral 10 denotes a spindle motor as a driving motor 
which is formed with a motor shaft 11 at an upper portion thereof. A 
supporting shaft member 20 is integrally formed with a cylindrical core 
portion 21 fitted with spindle motor shaft 11 and a supporting portion 22 
for supporting a disc stand member 30. A plurality of insertion holes 24 
are formed in the bottom plane of supporting portion 22 which has a 
circular groove 23 along the outer circumference thereof. Disc stand 
member 30 is shaped as a disc having an opening 32 in the center for 
receiving supporting shaft member 20 therethrough. The inner periphery of 
disc stand member 30 is engaged into outer circular groove 23 in 
supporting portion 22 of supporting shaft member 20. Disc stand member 30 
is formed with a bending portion 31 which is upwardly bent for seating a 
disc thereon. A spring 60 is fitted to an upper portion of cylindrical 
core portion 21 of supporting shaft member 20. A pressing member 40 is put 
on cylindrical core portion 21 of supporting shaft member 20 coupled with 
spring 60. Pressing member 40 is formed with hook-like projections 41 
directing downward to be respectively inserted to insertion holes 24 of 
supporting shaft member 20. 
Then, as shown in FIG. 2, turntable assembly T is installed under the state 
of being inserted with motor driving shaft 11. While disc 50 is mounted to 
the upper portion of turntable assembly T, information within disc 50 can 
be reproduced by actuating the rotation of spindle motor 10. 
As described above, turntable assembly T undergoes the assembling process 
under the state that spindle motor shaft 11 is forcibly press-fitted into 
cylindrical core portion 21 of supporting shaft member 20. A conventional 
apparatus for press-fitting the turntable employed for this process 
consists of a jig for holding the outer periphery of driving motor 10 at 
the lower side thereof and a magnetic chuck for electrically holding 
supporting shaft member 20 of turntable assembly T at the upper side 
thereof. 
Under this state, the jig is moved upward and the magnetic chuck is moved 
downward to pressively fitting rotating shaft 11 of driving motor 10 fixed 
to the jig into the turntable fixed to the magnetic chuck, thereby 
assembling the elements. 
In the above-mentioned conventional press-fitting process, however, when 
driving motor shaft 11 is press-fitted into cylindrical core portion 21 of 
supporting shaft member 20 of turntable assembly T, rotating shaft 11 of 
driving motor 10 is warped due to the press-fitting force exerting in the 
axial direction to cause an eccentric error around the motor shaft portion 
after finishing the press-fitting process. Furthermore, the outer 
periphery of driving motor 10 is held by means of the jig, and the outer 
periphery of turntable assembly T is held by means of the magnetic chuck 
to be highly probable to produce the eccentric error at the cylindrical 
core portion and motor shaft portion which are the center portion. For 
these reasons, turntable assembly T is not precisely joined with driving 
motor shaft 11 to be liable to shake cylindrical core portion 21 of 
turntable assembly T with the consequence of degrading playback accuracy 
when the disc is being reproduced. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an apparatus for 
automatically press-fitting a turntable capable of minimizing an eccentric 
error by inserting a rotating shaft of a driving motor into a turntable 
assembly with significantly high precision. 
To achieve the above object of the present invention, an apparatus for 
automatically press-fitting a turntable includes a driving motor fixing 
part for installing a driving motor to be attachable/detachable state. 
Also, a turntable assembly fixing part for attachably/detachably 
installing a turntable assembly has a center arranged at an extending line 
of a motor shaft of said driving motor to permit a rotating shaft of said 
turntable assembly to be accurately coaxial with said driving motor when 
the turntable assembly is installed thereto. A motor shaft fixing part 
installed to an upper portion of a drive chassis coupled onto the driving 
motor for fixing the motor shaft includes a stand portion which is 
arranged to an upper portion of the driving motor and formed with an 
elongated guide hole capable of receiving/separating the motor shaft, and 
a motor shaft supporting portion which has a sidewall upwardly bent to 
perpendicularly extend from an edge of the elongated guide hole of the 
stand portion for supporting the motor shaft by closely contacting the 
motor shaft when the motor shaft is inserted. 
Here, the motor shaft fixing part is formed to be attachable/detachable 
to/from the driving motor part by a magnetic force. 
Preferably, the turntable fixing part is formed with an insertion lug at 
the lower surface thereof for being inserted/separated into/from a groove 
installed in an upper corresponding surface of a turntable portion, so 
that the turntable is firmly coupled to the turntable assembly fixing part 
when the driving motor shaft is press-fitted into the turntable assembly. 
While the driving motor shaft is press-fitted into the turntable assembly, 
a permanent magnet is installed to the lower portion of the turntable 
attached to the lower portion of the turntable assembly fixing part for 
securely attaching the turntable assembly to the turntable assembly fixing 
part. 
It is preferable that the turntable assembly fixing part is formed with a 
guiding slot in the lower surface thereof. An elastic member exercising an 
elastic motion in the up and down direction is installed to the upper 
portion of the guiding slot within the turntable assembly fixing part, and 
guide member is installed in contact with the elastic member at the lower 
portion of the elastic member. The guide member consists of a flat-type 
upper plane capable of performing the elastic motion by contacting the 
elastic member within the turntable assembly, and a guide rod for being 
inserted into a rotating shaft part of the turntable assembly while 
penetrating through the guiding slot to move in the up and down direction. 
The turntable assembly fixing part and motor shaft fixing part are 
installed such that the guide rod inserted into the rotating shaft part of 
the turntable assembly is exactly coaxial with the motor shaft of the 
driving motor. 
In view of the apparatus for automatically press-fitting the turntable, 
while the driving motor shaft is press-fitted into the rotating shaft of 
the turntable assembly, the motor shaft fixing part grips around the motor 
shaft for preventing the shaking of the motor shaft to inhibit the warping 
of the motor shaft. Therefore, the skew in the axial direction of the 
turntable can be prevented after the press-fitting process to enhance 
playback accuracy when the disc is reproduced. 
In addition, the assembling is carried out under the state that the 
rotating shaft portion of the turntable assembly and shaft portion of the 
driving motor are respectively gripped, so that the turntable assembly and 
driving motor shaft are joined with significantly high precision to 
further enhance the playback accuracy during the reproduction of the disc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Hereinbelow, an apparatus for automatically press-fitting a turntable 
according to the present invention will be described with reference to the 
accompanying drawings in detail. 
FIG. 3 is a diagrammatic section view showing the apparatus for 
automatically press-fitting the turntable according to the present 
invention, and FIG. 4 is a perspective view showing the motor shaft fixing 
part of the apparatus for automatically press-fitting the turntable of 
FIG. 3. FIG. 5 is a sectional view showing a state that the turntable 
assembly and motor part are mounted to the apparatus for automatically 
press-fitting the turntable shown in FIG. 3 for inserting the motor 
driving shaft into the rotating shaft part of the turntable assembly. 
As illustrated in FIGS. 3 to 5, a reference numeral 120 denotes a driving 
motor fixing part for installing a driving motor 210 to be 
attachable/detachable to/from the interior thereof. Motor fixing part 120 
is formed with a spindle motor installing groove 122 into which a spindle 
motor 210 is inserted. 
A drive chassis 160 is provided for arranging a turntable assembly 200 
joined with spindle motor 210 on the upper plane thereof when a disc is 
recorded/reproduced. Spindle motor 210 is screw-coupled to the lower 
portion of drive chassis 160 in such a manner that a motor shaft 211 of 
spindle motor 210 penetrates through drive chassis 160 to upwardly project 
in the vertical direction. Drive chassis 160 is installed onto a base 121 
of motor fixing part 120 under the state that spindle motor 210 joined at 
the lower portion of drive chassis 160 is installed to spindle motor 
installing groove 122. 
While spindle motor 210 is screw-coupled to drive chassis 160, spindle 
motor 210 is inserted into spindle motor installing groove 122 of motor 
fixing part 120 provided to the lower portion of spindle motor 210. 
A motor shaft fixing part 130 is attachably/detachably installed to the 
upper portion of drive chassis 160 coupled onto driving motor 210. A stand 
132 of motor shaft fixing part 130 is installed to the upper portion of 
driving motor 210, and formed with an elongated guide hole 136. A sidewall 
bent to perpendicularly extend to the upward direction from an edge of 
elongated guide hole 136 of stand 132 is provided to the upper portion of 
stand 132 to form a motor shaft supporting part 134 in a body for 
supporting motor shaft 211 by closely contacting motor shaft 211 when 
motor shaft 211 is inserted. 
A turntable assembly fixing part 170 is for attachably/detachably 
installing turntable assembly 200. Turntable assembly fixing part 170 
allows the central axis thereof to be correctly arranged onto an extending 
line of driving motor shaft 211. By doing so, a rotating shaft 201 of 
turntable assembly 200 becomes exactly coaxial with motor shaft 211 of 
driving motor 210 when turntable assembly 200 is installed. 
Turntable assembly fixing part 170 has an annular projection 171 inserted 
with a supporting shaft member 220 of turntable assembly 200 at the lower 
portion of the central axis thereof. Also, a guiding slot 172 for 
permitting annular projection 171 to pierce therethrough in the up and 
down direction is formed in turntable assembly fixing part 170. An elastic 
spring 173 is installed to the upper portion of guiding slot 172 within 
turntable assembly fixing part 170 to perform the elastic motion in the up 
and down direction. 
An upper wall 175 is installed over the upper portion of elastic spring 173 
to fix an upper end of elastic spring 173, and a guide pin 190 having a 
T-shaped section is installed to contact a lower end of elastic spring 
173. Guide pin 190 is formed by a flat-type upper plane 191 and a guide 
rod 192 integrally connected with upper plane 191. Upper plane 191 of 
guide pin 190 is arranged in contact with the lower end of elastic spring 
173 to be movable up and down within turntable assembly fixing part 170 
dependent upon the elastic motion of elastic spring 173. Guide rod 192 of 
guide pin 190 is formed with upper plane 191 in a body, and inserted into 
rotating shaft 201 of turntable assembly 200 while moving up and down by 
piercing through guiding slot 172. 
Thus, guide pin 190 arranged to exactly correspond guiding slot 172 of 
turntable assembly fixing part 170 to guide rod 192 is fitted into 
supporting shaft member 220 of turntable assembly 210. Accordingly, 
turntable assembly 210 can keep the balance rarely involving any error. 
Turntable assembly fixing part 170 is formed with an insertion lug 178 to 
the lower plane of annular projection 171 which contacts the upper surface 
of a turntable when mounting turntable assembly 200. A groove 179 is 
formed in the upper corresponding surface of the turntable portion for 
receiving/separating insertion lug 178. By this construction, turntable 
assembly 200 is firmly joined to turntable assembly fixing part 170 while 
driving motor shaft 211 is press-fitted into turntable assembly 200. 
A permanent magnet 140 is installed to the lower portion of the turntable 
attached to turntable assembly fixing part 170 in the process of 
press-fitting driving motor shaft 211 into turntable assembly 200, thereby 
securely attaching turntable assembly 200 to turntable assembly fixing 
part 170. 
A guide bearing 177 is installed to the sidewall of guiding slot 172 of 
turntable assembly fixing part 170 for facilitating the up and down motion 
of guide pin 190. 
A reference numeral 179 denotes an ascending gripping member for gripping 
to allow turntable assembly fixing part 170 which is to be mounted with 
turntable assembly 170 to move up and down. 
Now, an operation of the apparatus for automatically press-fitting the 
turntable will be described. 
FIG. 5 is the sectional view showing the state that the turntable assembly 
and motor part are mounted to the apparatus for automatically 
press-fitting the turntable shown in FIG. 3 for inserting the motor 
driving shaft to the rotating shaft part of the turntable assembly. FIG. 6 
is a sectional view showing a state that the motor driving shaft is 
inserted to the rotating shaft part of the turntable assembly by means of 
the apparatus for automatically press-fitting the turntable mounted with 
the turntable assembly and motor part. 
As shown in FIG. 5, in order to insert motor shaft 211 of driving motor 210 
within supporting shaft member 220 of turntable assembly 200, supporting 
shaft member 220 of turntable assembly 200 is primarily fitted into 
annular projection 171 of turntable fixing member 170. At this time, the 
end of guide pin 190 protruding from annular projection 171 after piercing 
through guiding slot 172 is inserted into rotating shaft 201 of turntable 
assembly 200, thereby accurately keeping the balance of turntable assembly 
200. Then, turntable assembly 200 is joined by the magnetic force of 
turntable assembly fixing part 170. 
Meantime, insertion lug 178 formed to the lower plane of annular projection 
171 of turntable assembly fixing part 170 is fitted into groove 179 formed 
in the corresponding portion of the upper surface of the turntable. Thus, 
turntable assembly 200 is more firmly joined to turntable assembly fixing 
part 170. 
Permanent magnet 140 is installed to the lower portion of the turntable 
attached to the lower portion of turntable assembly fixing part 170 to 
securely attach turntable assembly 200 to turntable assembly fixing part 
170. 
While motor shaft 211 of spindle motor 210 upwardly protrudes in the 
vertical direction by piercing through a motor shaft thruhole of drive 
chassis 160, spindle motor 210 is screw-coupled to drive chassis 160. 
Under the state that spindle motor 210 is screw-coupled to drive chassis 
160, spindle motor 210 is inserted into spindle motor installing groove 
122 of motor fixing part 120 provided to the lower portion of spindle 
motor 210. Thereafter, motor fixing part 120 fixes driving motor 210 and 
drive chassis 160 installed with motor shaft 211 of driving motor 210 by 
means of a magnetic force. 
Motor shaft fixing part 130 is attachably/detachably installed to the upper 
portion of drive chassis 160 coupled onto driving motor 210 by means of 
the magnetic force. Then, spindle motor shaft 211 is inserted along the 
sidewall of motor shaft supporting part 134 of motor shaft fixing part 
130. By thoroughly inserting motor shaft 121 into motor shaft supporting 
part 134, motor shaft 211 is supported by motor shaft supporting part 134 
in the whole direction excluding the inserting direction. 
After this, when turntable assembly 200 descends by ascending gripping 
member 179 of turntable assembly fixing part 170, rotating shaft 201 of 
turntable assembly 200 meets the upper end of motor shaft 211. By 
continuously descending turntable assembly 200, motor shaft 211 is 
inserted into rotating shaft 201. 
Since rotating shaft 201 of turntable assembly 200 is accurately coaxial 
with motor shaft 211 of driving motor 210, motor shaft 211 is inserted to 
exactly correspond to supporting shaft member 220 of turntable assembly 
200. 
Successively, motor shaft 211 upwardly pushes guiding slot 172 and guide 
pin 190 having the T-shaped section movable up and down within guiding 
slot 172 of turntable fixing member 170. Here, the central axis of guide 
pin 190 is accurately coaxial with motor shaft 211 of driving motor 210. 
Therefore, as shown in FIG. 6, guide member 190 is continuously pushed 
upward by motor shaft 211 and motor shaft 211 of driving motor 210 is 
completely inserted within supporting shaft member 220 of turntable 
assembly 200 while constricting spring 173 at the upper portion thereof. 
The continuous descending of turntable assembly fixing part 170 further 
inserts spindle motor 210, and, therefore, guide rod 192 and insertion 
projection 178 are upwardly biased to be drawn out from turntable assembly 
200. Accordingly, turntable assembly fixing part 200 is separated from 
turntable assembly 200. 
Then, turntable assembly fixing part 170 ascends to the original position 
thereof by ascending gripping member 179. At this time, guide member 190 
returns to the original state by the restoring force of elastic spring 
173. 
By doing so, the press-fitting of driving motor 210 with respect to 
turntable assembly 200 is completed. 
Driving motor 210 installed to drive chassis 160 and turntable assembly 200 
press-fitted into motor shaft 211 of driving motor 210 according to the 
above-described process are employed as one constituent during 
manufacturing an optical disc player. 
In the apparatus for automatically press-fitting the turntable constructed 
as above, when the driving motor shaft is press-fitted into the rotating 
shaft portion of the turntable assembly, the motor shaft is held to be 
gripped by the motor shaft fixing part around the motor shaft not to be 
shaken. As the result, the warpage of the motor shaft caused by the 
press-fitting force in the axial direction is prevented to inhibit the 
skew in the axial direction of the turntable after finishing the 
press-fitting process, thereby raising playback accuracy during the 
reproduction of the disc. 
Additionally, the joining of the rotating shaft part of the turntable 
assembly and shaft part of the driving motor is carried out with the 
significantly high precision while being respectively settling them to 
further raise playback accuracy during the reproduction of the disc. 
While the present invention has been particularly shown and described with 
reference to particular embodiment thereof, it will be understood by those 
skilled in the art that various changes in form and details may be 
effected therein without departing from the spirit and scope of the 
invention as defined by the appended claims.