Metal deforming – By use of closed-die and coacting work-forcer – Cup or shell drawing
Utility Patent
1999-04-28
2001-01-02
Larson, Lowell A. (Department: 3725)
Metal deforming
By use of closed-die and coacting work-forcer
Cup or shell drawing
C072S417000
Utility Patent
active
06167741
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a silent structure of a processing machine, a silent structure of a pressing machine, a silent structure of a pressing die, and more particularly, to a silent structure of a drawing die and a silent run-up unit thereof used when a metal plate part such as an automobile or an electric home appliance is subjected to a drawing working.
2. Description of Background Art
The background of the present invention will be explained based on the drawing die as an example.
FIG. 9
shows one example of the drawing die. The drawing die comprises a punch
101
located at a central position of the drawing die, a blank holder
103
fitted around the punch
101
and vertically movably supported by a cushion pin
102
, and a die
104
disposed such as to oppose the punch
101
for vertical movement. The reference number
105
represents an air vent.
A lower die
109
comprising the punch
101
and the blank holder
103
is fixed to a bolster
106
of a pressing machine, and an upper die
110
comprising the die
104
is fixed to a ram
107
of the pressing machine. The upper die
110
moves vertically by driving the pressing machine. The blank holder
103
is supported by the cushion pin
102
, the cushion pin
102
is moved vertically by a cushion device of the pressing machine and with this movement, the blank holder
103
is also moved vertically.
A drawing processing will be explained. First, the blank holder
103
is moved up to a position shown with phantom lines by the cushion pin
102
.
Next, a thin plate
108
is placed on the blank holder
103
and the punch
101
as shown with the phantom lines.
Then, if the upper die
110
is lowered, the die
104
collides against the thin plate
108
on the blank holder
103
around the entire outer periphery of the punch
101
so that the thin plate
108
is sandwiched between the blank holder
103
and the die
104
. Subsequently, if the upper die
110
is lowered, the thin plate
108
sandwiched between the blank holder
103
and the die
104
is drawn by the punch
101
, and when the upper die
110
reaches the bottom dead center, the thin plate
108
is drawn to form a workpiece W.
If the upper die
110
moves up, the blank holder
103
is moved up to the position shown with the phantom lines by the ascending force of the cushion pin
102
, and the workpiece W is removed from the punch
101
. The die
104
of the upper die
110
is provided with the air vent
105
so that the negative pressure is prevented from being generated between the workpiece W and the die
104
when the workpiece W is dropped by its own weight. Alternatively, the workpiece W may be moved downwardly by a push pin (not shown) biased by a spring, thereby removing the workpiece W from the die
104
. The workpiece W removed from the pressing machine is transferred to the a pressing machine of the next step.
In the above described drawing working, when the die
104
collides against the thin plate
108
placed on the blank holder
103
, die
104
and the thin plate
108
over the entire outer peripheral surface of the punch
101
(i.e., the thin plate
108
on the blank holder
103
) are directly contacted with each other concurrently and since the upward biasing pressure of the cushion
102
may be about 60 to 100 tons in some cases, a great noise of 110 dB or higher is generated. Since a quiet workplace environment is required in recent years, the noise of the drawing die is not socially acceptable.
In order to prevent the noise generated when the die collides against the thin plate on the blank holder of the drawing die, an attempt was made to provide a urethane rubber or a gas spring on the blank holder so that the die collided against the urethane rubber or the gas spring before colliding against the thin plate, thereby absorbing the impact force to reduce the noise. However, a sufficient effect could not be obtained.
Further, so as to prevent the noise from being generated outside, there is an example that the pressing machine is surrounded by a soundproof wall. However, an opening must be formed in the soundproof wall for bringing in and out the workpiece from and to the pressing machine and thus, the noise leaks from the opening. On the other hand, an operator working in the vicinity of the pressing machine surrounded by the soundproof wall is bothered by the great noise.
Further, when the die collides against the thin plate on the blank holder, an attempt was made to reduce the cushion pressure only during a certain time period of initially lowering movement of the cushion pin. However, the cushion device of the pressing machine must be improved, which is too expensive.
SUMMARY AND OBJECTS OF THE INVENTION
Although the above description has been made based on the drawing die of the pressing die as the example, not only the noise of the drawing die, but also a noise of a pressing die sandwiching a thin plate or a workpiece for machining or working is also not socially acceptable.
Further, in relation to the pressing die, the noise of a pressing machine having a pressing die, and the noises of other processing machines for metal or resin are also regarded as not socially acceptable
Since a quiet environment is required in recent years, it is required to reduce the noise generated by a processing machine, a pressing machine and a pressing die as small as possible.
Especially in the drawing die, a great noise is generated when a die collides against a thin plate on a blank holder, and it is required to reduce this noise as small as possible.
Thereupon, so as to reduce the noise generated from a processing machine as small as possible, according to the present invention, there is provided a silent structure of a processing machine comprising a stationary bed, a movable member vertically movable with respect to the bed, a pad of a cushion device located below the bed for biasing a cushion pin upwardly, wherein the stationary member is rotatably provided with a run-up lever, the movable member facing the run-up lever is vertically provided with an operation cam, the operation cam acts on the run-up lever before mounted working tools sandwich a workpiece, and the pad is allowed to run up.
Further, so as to reduce the noise generated from a pressing machine as small as possible, according to the present invention, there is provided a silent structure of a pressing machine comprising a stationary bed, a ram vertically movable with respect to the bed, a pad of a cushion device located below the bed for biasing a cushion pin upwardly, wherein the stationary member is rotatably provided with a run-up lever, the ram facing the run-up lever is vertically provided with an operation cam, the operation cam acts on the run-up lever before mounted pressing dies sandwich a thin plate or a workpiece, and the pad is allowed to run up.
Further, so as to reduce the noise generated from a drawing die as small as possible, according to the present invention, there is provided a silent structure of a drawing die comprising a punch, a blank holder fitted around the punch and vertically movably supported by a cushion pin, and a vertically movable die disposed such as to face the punch, a thin plate being placed on a blank holder which is moved up by the cushion pin, the die being lowered, thereby sandwiching the thin plate between the blank holder and the die for drawing the thin plate by the punch, wherein a lower base plate is rotatably provided with a run-up lever for pushing the blank holder for allowing the latter to run up before the die collides against the thin plate, an operation cam for driving the run-up lever is disposed at a position on the die facing the run-up lever, and the die collides against the thin plate on the blank holder after the blank holder runs up.
Furthermore, according to the invention, the operation cam has a cam surface a tilt angle for changing speed.
Further, in order to facilitate the improvement of the existing drawing die to include a silent structure, there is provided a s
Birch & Stewart Kolasch & Birch, LLP
Larson Lowell A.
Umix Co., Ltd.
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