Metal deforming – By use of tool acting during relative rotation between tool... – Tool orbiting or rotating about an axis
Reexamination Certificate
2002-12-17
2004-07-27
Tolan, Ed (Department: 3725)
Metal deforming
By use of tool acting during relative rotation between tool...
Tool orbiting or rotating about an axis
C072S122000, C072S452800
Reexamination Certificate
active
06766675
ABSTRACT:
TECHNICAL FIELD
This invention relates to a spindle mechanism, and more particularly to a spindle mechanism in a drawing apparatus, in which drawing tools, while revolved, are slid in a radial direction.
BACKGROUND ART
As shown in
FIG. 14A
, there is known a conventional method in which drawing tools (spinning rollers)
102
are moved in a direction X—X (axial direction) and a direction Y—Y (radial direction) at an end portion of a tube
101
of metal, the end portion of the tube
101
is drawn by spinning, and a gradually-tapered portion
103
and a smaller-diameter portion
104
are formed integrally at the end portion of an ordinary portion (stock tube portion)
101
a
of the tube in coaxial relation thereto. As shown in
FIG. 14B
, there is known another method in which a gradually-tapered portion
103
and a smaller-diameter portion
104
are formed in an eccentric (offset) relation to an axis of an ordinary portion (stock tube portion) of a tube
101
. Although not shown in the drawings, there is known a further method in which the gradually-tapered portion
103
and the smaller-diameter portion
104
are formed in an oblique and skew relation to the axis of the tube
101
. Methods of forming such tubes are disclosed, for example, in JP-B2-2957153 and JP-B2-2957154.
Among the above spinning methods, for example, JP-B2-3-008412 discloses a spindle mechanism of a special-purpose apparatus for effecting a spinning operation, in which a workpiece (stock tube) is fixed, and the spinning is carried out by revolving spinning rollers. In the spindle mechanism proposed and disclosed in this publication, a spindle and an auxiliary shaft (cam shaft) are provided coaxially with each other, and a slide base is mounted on one of the two while a cam plate is mounted on the other, and the difference in rotational speed is produced between the slide base and the cam plate by the rotational speed difference between the spindle and the auxiliary shaft, and drawing tools (spinning rollers), mounted on the slide base, are arbitrarily moved in a radial direction by this rotational speed difference.
In the above conventional spindle mechanism, planetary gear mechanisms (planetary units) are provided respectively at the spindle and the auxiliary shaft in order to produce the rotational speed difference between the spindle and the auxiliary shaft, and these are worked with each other to form a speed-change system. The speed-change system is thus formed by working the two planetary gear mechanisms with each other, and therefore this system is complicated, and the weight and cost increase, and besides, a backlash and a rotational inertia loss are large, and therefore the efficiency is not good.
Furthermore, the heavy speed-change system is supported by the spindle and the auxiliary shaft, and thus the two shafts need to have a large strength, and there are encountered problems that it is difficult to achieve a lightweight design of the two shafts and that it is difficult to pass a mandrel or the like through the spindle.
In order to solve these problems, for example, EP1052035A1 discloses a drawing system in which a speed-change mechanism is provided separately from a spindle mechanism comprising such a spindle and a cam shaft (auxiliary shaft) as described above. However, since the independent speed-change mechanism is provided, there is encountered a problem that the compact, lightweight and low-cost design of the spindle mechanism can not be achieved satisfactorily.
It is therefore an object of this invention to provide a spindle mechanism which solve the above problems.
DISCLOSURE OF THE INVENTION
In order to solve the above problems, the present invention provides a spindle mechanism wherein a drawing tool-mounting member, on which drawing tools are supported for sliding movement in a radial direction, is provided at a distal end of a spindle, and a cam shaft is rotatably provided at the spindle in coaxial relation thereto, and a cam plate whose rotation causes the drawing tools to move in the radial direction is provided at a distal end of the cam shaft, and a relative rotation difference is produced between the spindle and the cam shaft, thereby moving the drawing tools in the radial direction;
characterized in that the relative rotation difference between the spindle and the cam shaft is produced by adjusting a condition of engagement of the spindle with the cam shaft.
With this construction, in a condition in which the spindle and the cam shaft rotate in the same direction, when the condition of engagement of the spindle with the cam shaft in the circumferential direction is adjusted, the relative rotation difference between the spindle and the cam shaft is produced, so that the drawing tools are moved in the radial direction.
In the present invention, the structure may be constructed that a slot is formed in one of the spindle and the cam shaft while a spiral torque cam groove is formed in the other to extend around an axis thereof, and a torque cam pin is engaged in the slot and the torque cam groove, and the torque cam pin is moved in the axial direction by drive means so as to change the relative position of the spindle with respect to the cam shaft in a circumferential direction.
In this construction, the longitudinal directions of the slot and the torque cam groove are inclined relative to each other, and therefore, when the torque cam pin engaged in the slot and the torque cam groove is moved in the axial direction, the position of the spindle relative to the cam shaft in the circumferential direction is changed, and the relative rotation difference is produced between the spindle and the cam shaft, so that the drawing tools are moved in the radial direction.
In the present invention, the structure also may be so constructed that the cam shaft is mounted within the spindle in coaxial relation thereto, and the slot is formed in the spindle, and the torque cam groove is formed in the cam shaft.
In this construction, also, similar effects as described above are achieved.
In the present invention, further, the structure may be constructed that a holder is mounted on an outer periphery of the spindle for rotation and for sliding movement in the axial direction, and the torque cam pin is provided at the holder, and the holder can be moved in the axial direction by drive means.
In this structure, the holder provided with the torque cam pin is mounted on the outer periphery of the spindle, and when the torque cam pin is moved with the holder in the direction of the axis of the spindle, the holder is satisfactorily moved in the axial direction since the slot is formed in the spindle.
In the present invention, the structure can be also constructed that the spindle and the cam shaft are made of a hollow tube, respectively, and the latter is fitted into the former so as to rotate relatively to each other, and a mandrel is provided in the hollow tube of a smaller diameter so as to move forward and backward.
In this construction, the mandrel can be arranged so as to move in the axial direction in a center portion of the spindle and cam shaft.
REFERENCES:
patent: 4061009 (1977-12-01), Kaporovich et al.
patent: 5788733 (1998-08-01), Dieckow
patent: 6295856 (2001-10-01), Tobimatsu et al.
patent: 6368052 (2002-04-01), Uesugi et al.
patent: 1052035 (2000-11-01), None
patent: 1151812 (2001-11-01), None
patent: 1-198334 (1989-08-01), None
patent: 01258833 (1989-10-01), None
patent: 01258834 (1989-10-01), None
patent: 38412 (1991-02-01), None
patent: 2957153 (1999-07-01), None
patent: 2957154 (1999-07-01), None
patent: 2001030018 (2001-02-01), None
International Search Report dated Jul. 30, 2002.
Sakuragawa Kiyofumi
Suzuki Yukinori
Sango Co. Ltd.
Stevens, Davis, Miller & Mosher, LLP.
Tolan Ed
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