Electrical generator or motor structure – Dynamoelectric – Reciprocating
Reexamination Certificate
2001-12-31
2004-03-02
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Reciprocating
C074S025000, C074S110000
Reexamination Certificate
active
06700231
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a thrust converter for driving a press-working machine or a chucking apparatus for holding a workpiece through use of a lathe, to a method of controlling the thrust converter, and to a controller for controlling the thrust converter.
BACKGROUND ART
A press-working machine or a drive machine having a chucking mechanism for holding a workpiece through use of a machine tool or the like often employs thrust induced by a hydraulic cylinder or a pneumatic cylinder.
FIG. 13
is a fragmentary longitudinal cross-sectional view showing one example of a related-art press-working machine using a hydraulic cylinder as a drive source. A hydraulic cylinder
51
is secured on a stand
52
byway of a cylinder bracket
50
and is connected to a hydraulic system
53
via a pipe
54
. A push-pull rod
56
is fixed to a load-side extremity of a piston
55
of the hydraulic cylinder
51
. A press punch
57
matching a geometry to be machined is attached to the extremity of the push-pull rod
56
. A work table
58
is situated in a lower position within the stand
52
, and a workpiece
59
is fixedly placed on the work table
58
. The push-pull rod
56
is guided by the cylinder bracket
50
by way of a slide guide
60
so as to be slidable in the axial direction.
In such a related-art press-working machine, the piston
55
of the hydraulic cylinder
51
is reciprocated by means of oil supplied from the hydraulic system
53
by way of the pipe
54
. By means of thrusting action of the push-pull rod
56
fixed to the piston
55
, the press punch
57
is pushed, to thereby press, into a desired geometry, the workpiece
59
fixedly placed on the work table
58
.
FIG. 14
is a fragmentary transverse cross-sectional view showing one example of related-art chucking apparatus using a hydraulic cylinder as a chuck drive source. A rotary hydraulic cylinder
64
is supported by a cylinder cover
66
via shaft bearings
65
a
and
65
b
. A rear extremity of a main spindle
70
is secured on a load-side extremity of the rotary hydraulic cylinder
64
via an adapter
72
a.
A chuck
71
is secured on the front extremity of the main spindle
70
via an adapter
72
b
. A draw bar
73
is inserted into an internal hollow spindle core of the main spindle
70
, and the extremity of the draw bar
73
is engaged with chuck claws
74
via an operation conversion mechanism
75
. The operation conversion mechanism
75
converts axial operation of the draw bar
73
into radial operation of the chuck claws
74
by means of a cam lever or a taper.
The rear extremity of the draw bar
73
is secured to the load-side extremity of a piston
55
of the rotary hydraulic cylinder
64
.
In the related-art chuck drive system using a hydraulic cylinder as a chuck drive source, oil is supplied to the rotary hydraulic cylinder
64
from a hydraulic system
53
via a pipe
54
, thereby reciprocating the piston
55
. The axial operation of the draw bar
73
is converted into a radial operation of the chuck claws
74
, thereby causing the chuck
71
to hold a workpiece
67
.
After the chuck claws
74
have held the workpiece
67
, a main spindle motor
76
is rotated, thereby cutting the workpiece
67
and causing rotation of the main spindle
70
, the draw bar
73
, the chuck
71
, the operation conversion mechanism
75
, the rotary hydraulic cylinder
64
, the piston
55
, the workpiece
67
, and the adapters
72
a
and
72
b
, thereby machining the workpiece
67
.
In the related-art examples, a hydraulic cylinder is used for a press-working machine or a chucking apparatus. The same also applies to a case where a pneumatic cylinder is employed.
Another related-art example is a chucking apparatus using an electric motor as a chuck drive source described in Japanese Patent Application Laid-Open No. 34708/1987.
The chucking apparatus described in Japanese Patent Application Laid-Open No. 34708/1987 employs an electric motor as a chuck drive source. Drive force of the electric motor is amplified by a decelerator, and the thus-amplified drive force is transmitted to the chucking apparatus main unit. The chuck is closed by means of the thus-amplified drive force, thereby holding a workpiece.
At the time of machining operation, the workpiece is machined while a draw bar drive system is separated from a rotary system of the main spindle by means of an electromagnetic clutch.
In a press-working system or a chucking apparatus employing a related-art hydraulic cylinder or pneumatic cylinder, thrust is determined by the pressure which a hydraulic or pneumatic system can produce as well as by the diameter of the cylinder. When greater thrust is required, the pressure and/or the diameter must be changed correspondingly, thereby adding to costs.
Some decelerators employ gears as a torque amplification (or torque reduction) mechanism. Such a decelerator usually amplifies (or reduces) a rotational input and outputs as a rotational output. In order to amplify (or reduce) an axial input (or thrust) and output an axial output (thrust), mechanical components such as various gears must be combined together, thereby rendering the chucking apparatus bulky. Reactive force is exerted on a bearing which supports gears in a rotatable manner, thereby shortening the life of the decelerator. For this reason, a desire exists for a low-cost, compact, long-life thrust converter of simple construction which can amplify (reduce) an axial input (thrust) and output the thus-amplified axial input as an axial output (thrust).
Employment of a decelerator adopting a gear mechanism for amplifying the rotation torque of a motor, as in, for example, a chucking apparatus described in Japanese Patent Application Laid-Open No. 34708/1987, requires an electromagnetic clutch for separating a draw bar drive system from a main spindle rotation system during machining of a workpiece. Thus, the chucking apparatus presents a problem of an increase in the number of components, thereby adding to costs.
In the electromagnetic chucking apparatus, a workpiece is held by imparting axial thrust to a draw bar. During machining of a workpiece, a bearing which rotatably supports the draw bar receives all reaction force of axial thrust. Hence, an increase in the rotational speed of the main spindle or an increase in holding force due to an increase in axial thrust of a draw bar poses problems of drastically shortening the life of a bearing.
DISCLOSURE OF THE INVENTION
The present invention provides a thrust converter comprising:
reciprocating movement means;
reciprocation-rotation conversion means for converting reciprocating movement of the reciprocation movement means into rotational movement;
rotation-reciprocation conversion means for converting rotational movement of the reciprocation-rotation conversion means into reciprocating movement; and
reaction-force receiving means for supporting reaction force of reciprocating movement of the rotation-reciprocation conversion means.
Hence, thrust imparted to the reciprocation movement means can be imparted to a load while being amplified or reduced, through employment of a compact and simple construction. So long as the thrust converter is applied to a press-working machine or a chuck drive machine, thereby providing a useful novel thrust converter.
Preferably, the reciprocation movement means, the reciprocation-rotation conversion means, the rotation-reciprocation conversion means, and the reaction-force receiving means are aligned in one line, and a through hole is formed so as to pass through the center axes thereof.
Hence, there can be provided a thrust converter which can be applied to a lathe chuck for machining long materials.
Preferably, the reciprocation-rotation converter means comprises a first screw member to which axial thrust is imparted by the reciprocation movement means, a second screw member to be screw-engaged with the first screw member, and a first detent section for locking the first screw member so as to restrict movement to only an axial direction; the rotation-reciprocation convers
Hatsutori Yoshiyuki
Ito Hidenobu
Kasuga Yoshio
Mimura Seiichi
Mizutani Takao
Jones Judson H.
Mitsubishi Denki & Kabushiki Kaisha
Tamai Karl
LandOfFree
Thrust converter, method of controlling the same, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thrust converter, method of controlling the same, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thrust converter, method of controlling the same, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3242833