DIE

Abstract

A die includes a stationary die, a movable die, which is opposed to the stationary die and reciprocatable in a first direction to change a distance between the stationary and movable dies, and a transfer mechanism, which transfers a workpiece, upon which plastic deformation work is performed between the stationary and movable dies, in a second direction crossing the first direction. The transfer mechanism includes a clamp portion, which clamps/unclamps the workpiece, a synchronizing member, which is engaged with the movable die to reciprocate in synchronization with reciprocation of the movable die, a clamp-unclamp operation converter, which converts reciprocation of the synchronizing member into clamping/unclamping of the workpiece by the clamp portion, and an advance-return operation converter, which converts reciprocation of the synchronizing member into advance-return operation of the clamp portion, whereby the clamp portion advances the workpiece in the second direction and is returned after advancement of the workpiece.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application No. 2009-142639 filed on Jun. 15, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a die having a transfer mechanism that transfers a workpiece upon which plastic deformation work, such as press working or forge processing, is performed between a stationary die and movable die.

2. Description of Related Art:

Conventionally, a transfer press machine that obtains driving force of a transfer device for a workpiece from a power output of a driving rotatable shaft of the press machine, is known as a transfer press machine that performs press work, which is plastic deformation work (see, for example, Japanese Unexamined Patent Application Publication No. 2004-337953). In addition, a transfer press machine that obtains the driving force of the transfer device from an actuator, which is provided separately from the press machine, is also known (see, for example, Japanese Unexamined Patent Application Publication No. 2005-059080).

However, in the conventional technology of the above-described Publication No. 2004-337953, a transmission mechanism for transmitting the output of the rotatable shaft of the press machine to an input terminal of the transfer device is necessary. Accordingly, the rotatable shaft of the press machine needs to be adapted for the transmission of the output. Moreover, a rotational position relationship between an output terminal of the rotatable shaft of the press machine and the input terminal of the transfer device considerably influences synchronization between press working operation and transferring operation. Accordingly, work for adjustment of the synchronization becomes complicated.

In the conventional technology of the above-described Publication No. 2005-059080, the press machine needs to be adapted to include a detecting means for detecting an operating position of the press machine, for the synchronization between press working operation and transferring operation.

As a result of an elaborate investigation into the above-described problems, the following method for the synchronization between the working and transferring operations has been found. That is, if a transfer mechanism that operates in accordance with a displacement state of a movable die as opposed to a stationary die, is given to a die for performing plastic deformation work on a workpiece, the working operation can be synchronized with the transferring operation without the adaptation of the working machine.

SUMMARY OF THE INVENTION

The present invention addresses at least one of the above disadvantages.

According to the present invention, there is provided a die for performing plastic deformation work upon a workpiece. The die including a stationary die, a movable die, and a transfer mechanism. The movable die is opposed to the stationary die and reciprocatable in a first direction to change a distance between the stationary die and the movable die. The transfer mechanism is configured to transfer the workpiece, upon which plastic deformation work is performed between the stationary die and the movable die, in a second direction that crosses the first direction. The transfer mechanism includes a clamp portion, a synchronizing member, a clamp-unclamp operation converter, and an advance-return operation converter. The clamp portion is adapted to clamp or unclamp the workpiece. The synchronizing member is engaged with the movable die to reciprocate in synchronization with reciprocal movement of the movable die. The clamp-unclamp operation converter is configured to convert reciprocal movement of the synchronizing member into clamping and unclamping of the workpiece by the clamp portion. The advance-return operation converter is configured to convert the reciprocal movement of the synchronizing member into advance-return operation of the clamp portion, whereby the clamp portion advances the workpiece in the second direction and is returned after advancement of the workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is a front view roughly illustrating a structure of a die in accordance with an embodiment of the invention;

FIG. 2 is a plan view roughly illustrating structures of a lower die and a transfer mechanism of the die;

FIG. 3 is a perspective view illustrating a main feature of the transfer mechanism;

FIG. 4 is a front view illustrating the main feature of the transfer mechanism;

FIG. 5 is a top view illustrating the main feature of the transfer mechanism viewed from an arrow V in FIG. 4;

FIG. 6 is a side view illustrating the main feature of the transfer mechanism viewed from an arrow VI in FIG. 4;

FIG. 7 is a timing diagram illustrating an exemplary operation of the die;

FIG. 8A is a perspective view illustrating an operating state of the main feature of the transfer mechanism that corresponds to time (A) in FIG. 7;

FIG. 8B is a perspective view illustrating an operating state of the main feature of the transfer mechanism that corresponds to time (B) in FIG. 7;

FIG. 8C is a perspective view illustrating an operating state of the main feature of the transfer mechanism that corresponds to time (C) in FIG. 7;

FIG. 8D is a perspective view illustrating an operating state of the main feature of the transfer mechanism that corresponds to time (D) in FIG. 7;

FIG. 8E is a perspective view illustrating an operating state of the main feature of the transfer mechanism that corresponds to time (E) in FIG. 7;

FIG. 9 is a conceptual diagram illustrating power transmission when the die is used for a press machine; and

FIG. 10 is a conceptual diagram illustrating power transmission when a die in accordance with a comparative example is used for the press machine.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the invention is described below with reference to the accompanying drawings.

As illustrated in FIG. 1, a die 1 includes a lower die 2 disposed on an upper surface of a bolster of a press machine (not shown), and an upper die 3 disposed on a lower surface of a slide of the press machine. The lower die 2 may correspond to a stationary die, and the upper die 3 may correspond to a movable die. In accordance with the reciprocation of the slide in upper and lower directions or in a vertical direction, the upper die 3 reciprocates in the upper and lower directions to change a distance in a direction in which the upper die 3 is opposed to the lower die 2. Plastic deformation work is performed on a workpiece (i.e., a part being worked on) between the lower die 2 and the upper die 3.

The die 1 includes a transfer mechanism 4 that transfers the workpiece, which is plastically deformed between the lower die 2 and the upper die 3, rightward in FIG. 1, on the lower die 2. The transfer mechanism 4 includes a linear crank mechanism 10 disposed on a leftward portion of a working stage (plastic deformation working part) in FIG. 1, and a clamping mechanism 20 and a feed mechanism 30 which extend rightward from the linear crank mechanism 10.

As illustrated in FIG. 2, the transfer mechanism 4 is one of a pair of transfer mechanisms 4, and the mechanisms 4 transfer the workpiece one after another to the working stage on the right side, with the workpiece clamped by a pair of holding fingers 40 that are opposed to each other. The holding finger 40 may correspond to a clamp portion. Although in FIG. 2, more than one holding finger 40 (in the present example, eight holding fingers 40), are provided for the transfer mechanism 4, for instance, in accordance with the number of working stages, a configuration and operation of the transfer mechanism 4 will be described below in reference to FIGS. 3 to 9, taking as an example a single holding finger 40.

As illustrated in FIGS. 3 to 6, the linear crank mechanism 10 extends in the upper and lower directions, and includes a rod 11 and a crank mechanism 12. An upper end portion of the rod 11 is engaged with the upper die 3 using, for example, a screw or a lock pin, so that the rod 11 is reciprocated in the upper and lower directions in synchronization with the reciprocation of the upper die 3. The crank mechanism 12 is disposed on a lower end side of the rod 11 and converts the reciprocation of the rod 11 into rotary movement of a rotatable shaft 13. The rod 11 may correspond to a synchronizing member. The clamping mechanism 20 converts the rotary movement of the rotatable shaft 13 into work clamp-unclamp operation of the holding fingers 40. The feed mechanism 30 converts the rotary movement of the rotatable shaft 13 into advance-return operation of the holding fingers 40 in rightward and leftward directions (i.e., in a direction of the rotatable shaft 13) in FIG. 4. The clamping mechanism 20 may correspond to a clamp-unclamp operation converter. The feed mechanism 30 may correspond to an advance-return operation converter.

The clamping mechanism 20 includes a generally fan-shaped flat plate cam 21, a swaying block body 22 as a follower, and a clamp base 24. The flat plate cam 21 is fixed to the rotatable shaft 13 of the crank mechanism 12, and rotated in accordance with the rotary movement of the rotatable shaft 13. The swaying block body 22 has a cam follower 22a that is in contact with an outer peripheral surface of the flat plate cam 21, and is displaced (swayed) in the upper and lower directions in accordance with the rotary movement of the flat plate cam 21. The holding finger 40 is fixed on the clamp base 24.

An inclined groove 22b (through hole) is formed on the swaying block body 22. The inclined groove 22b is inclined to be further away from the holding finger 40 toward an upper portion of the inclined groove 22b in the upper and lower directions. A penetrating bar 23, which extends in the rightward and leftward directions in FIG. 4 on the opposite side of the clamp base 24 from the holding finger 40, is provided to pass through the inclined groove 22b. The swaying block body 22 is surrounded with a guide member (not shown), so that the block body 22 is made movable only in the upper and lower directions without being inclined. The swaying block body 22 is constantly urged downward by a spring, for example.

Accordingly, while the rotatable shaft 13 is rotating, as a result of a cam mechanism that is made up of the flat plate cam 21 and the swaying block body 22, a function of guiding the penetrating bar 23 along the inclined groove 22b and so forth, the holding finger 40, which is provided to project from the clamp base 24, alternately repeats a state of clamping the workpiece with its distance to the opposing holding finger 40 reduced, and a state of unclamping the workpiece with its distance to the opposing holding finger 40 increased.

The swaying block body 22 is surrounded with the guide member, to be allowed to move only in the upper and lower directions. Alternatively, length of the flat plate cam 21 in the direction of the rotatable shaft 13 may be increased not to limit a position of the swaying block body 22 in the direction of the rotatable shaft 13.

The feed mechanism 30 includes a cylindrical groove cam 31 and a cam follower 32a (see FIG. 5). The groove cam 31 is fixed to the rotatable shaft 13 to rotate in accordance with the rotary movement of the rotatable shaft 13. The cam follower 32a projects into a groove 31a formed on an outer peripheral surface of the groove cam 31. The feed mechanism 30 includes a swaying rod 32, an operation rod 33, and a feeding bar 34 having an insertion hole 34a. The rod 32 has a supporting point 32b at a lower end portion of the rod 32. The rod 32 is swayed in a shape of a circular arc with its supporting point 32b serving as a center in accordance with the rotation of the cylindrical groove cam 31. The rod 33 projects upward in FIG. 5 from an upper end portion of the swaying rod 32. The operation rod 33 is inserted in the hole 34a such that the rod 33 is fitted into the hole 34a with some play.

A through hole 34b is formed in the feeding bar 34. The above-described clamp base 24 passes through the hole 34b. The clamp base 24 is movable only in upper and lower directions in FIG. 5 relative to the feeding bar 34. Accordingly, while the rotatable shaft 13 is rotating, as a result of a cam mechanism that is made up of the cylindrical groove cam 31 and the swaying rod 32, an engagement relationship between the operation rod 33 and the feeding bar 34, and so forth, an advancing operation to feed the workpiece by making the holding finger 40, which is provided to project from the clamp base 24, proceed rightward in FIG. 4 in the direction of the rotatable shaft 13, and a returning operation to return the workpiece by making the holding finger 40 proceed leftward in FIG. 4, are alternately repeated.

As a result of the combination of change of a distance from an shaft center of the shaft 13 to the outer peripheral surface of the flat plate cam 21 fixed to the rotatable shaft 13, and position change of the groove 31a of the cylindrical groove cam 31 fixed to the rotatable shaft 13 in an axial direction of the shaft 13, the clamp-unclamp operation and the advance-return operation are synchronized. More specifically, as illustrated in FIG. 7, in accordance with the reciprocation of the upper die 3 in upper and lower directions, the operation to advance the workpiece with the workpiece clamped (held) by the holding finger 40, and the operation to return the workpiece with the workpiece unclamped (released) from the holding finger 40 are alternately repeated.

FIGS. 8A to 8E illustrate states of a main feature of the transfer mechanism 4 at time (A) to time (E) in the timing diagram in FIG. 7.

At time (A) in FIG. 7, as illustrated in FIG. 8A, the holding finger 40 is advanced to a maximum extent toward a reverse side of a plane of paper, and holds the workpiece. When the upper die 3 makes the transition to descend from its lifted position and time elapses from time (A) to time (B), because of functions of the rod 11, the crank mechanism 12, the cam mechanism of the feed mechanism 30 and so forth, which coordinate with the upper die 3, as illustrated in FIG. 8B, the feeding bar 34 is made to proceed rightward, so that the holding finger 40 is also made to proceed rightward, holding the workpiece.

Then, when the upper die 3 continues going down and time elapses from time (B) to time (C), the holding finger 40 is moved backward to a maximum extent from its maximum forward position toward an upper side of the plane of paper so as to release the workpiece, without changing the position of the feeding bar 34 in rightward and leftward directions as illustrated in FIG. 8C, owing to functions of the rod 11, the crank mechanism 12, the cam mechanism of the clamping mechanism 20 and so forth in synchronization with the upper die 3.

When the upper die 3 makes the transition to be lifted up from its lowered position and time elapses from time (C) to time (E), as illustrated in FIG. 8E, the feeding bar 34 is made to proceed leftward, so that the holding finger 40 is also made to proceed leftward with the holding finger 40 located at its maximum backward position (with the workpiece released), because of the functions of the rod 11, the crank mechanism 12, the cam mechanism of the feed mechanism 30 and so forth, which coordinate with the upper die 3. At time (D) (i.e., at a maximum lowered position or bottom dead point of the upper die 3) in the course of the time between time (C) and time (E) when the upper die 3 makes the transition to be lifted up from its lowered position, the workpiece is pressed between the lower die 2 and the upper die 3.

When the upper die 3 continues being lifted up and time elapses from time (E) to time (A), owing to functions of the rod 11, the crank mechanism 12, the cam mechanism of the clamping mechanism 20 and so forth in synchronization with the upper die 3, as illustrated in FIG. 8A, without changing the position of the feeding bar 34 in rightward and leftward directions, the holding finger 40 is advanced to a maximum extent from its maximum backward position toward the reverse side of the plane of paper, so as to hold the workpiece.

As a result of the above-described configuration and operation of the die 1, in the transfer mechanism 4 of the die 1, the rod 11 is engaged with the upper die 3, so that the rod 11 is synchronized with the reciprocation of the upper die 3 in upper and lower directions. The reciprocation of the rod 11 is converted into the rotary movement of the rotatable shaft 13 in the crank mechanism 12. The rotary movement of the rotatable shaft 13 is converted in the clamping mechanism 20 into the operation of clamping-unclamping of the workpiece by the holding finger 40, and the rotary movement of the rotatable shaft 13 is also converted in the feed mechanism 30 into the operation to advance the holding finger 40 in a work transfer direction and to return the holding finger 40 in a counter-work transfer direction, i.e., into the advance-return operation (the holding finger 40 advances the workpiece in a direction that crosses the reciprocation direction of the upper die 3, and the holding finger 40 is returned after the advancement of the workpiece).

Accordingly, when the workpiece is pressed between the lower and upper dies 2, 3 of the die 1, the workpiece is transferred by the transfer mechanism 4 in synchronization with the reciprocation of the upper die 3. As above, press working operation and transferring operation are readily synchronized only by attaching the die 1 to the press machine without adapting the press machine.

As illustrated in FIG. 10, conventionally, when a die 101 is mounted on a press machine, in order to transmit power to a transfer mechanism 104, for instance, a rotatable shaft of the press machine (i.e., a position corresponding to a base end of a black arrow) needs to be adapted for output power. Even if a transfer mechanism having an actuator, which is provided separately from the press machine, is employed, for the sake of the synchronization between press working operation and transferring operation, the press machine needs to be adapted for the installation of a sensor for detecting an operating position of the press machine at the position of the press machine corresponding to the base end of the black arrow.

On the other hand, when the die 1 of the present embodiment is employed, as illustrated in FIG. 9, the transfer mechanism 4 is operated in the die 1 by means of a part of power of the press machine to operate the die 1.

Moreover, both the clamping mechanism 20 and the feed mechanism 30 convert the rotary movement of the rotatable shaft 13 into the clamp-unclamp operation and the advance-return operation of the holding finger 40 using their cam mechanisms. Therefore, the conversion of operation of the rotatable shaft 13 is made very easy.

The embodiment of the invention have been described above. However, the invention is not by any means limited to the above-described embodiment, and may be embodied through various modifications without departing from the scope of the invention.

Modifications of the above embodiment will be described below. In the above embodiment, the die 1 includes the lower die 2 and the upper die 3. Alternatively, the die 1 may be any die as long as it is a die that is made up of a stationary die and a movable die and that performs plastic deformation work on a workpiece between the stationary die and movable die. For example, the die 1 may be a die in which a movable die reciprocates in a horizontal direction to change an opposing distance between the movable die and a stationary die.

In the above embodiment, the flat plate cam 21 is used in the clamping mechanism 20, and the cylindrical groove cam 31 is employed in the feed mechanism 30. However, the cams of the cam mechanisms are not limited to the flat plate cam 21 and the cylindrical groove cam 31. For both the clamping mechanism 20 and the feed mechanism 30, for example, in the case of a plane cam, a plate cam, groove cam, rib cam, or conjugate cam may be used, and in the case of a solid cam, an end cam, cylindrical groove cam, cylindrical rib cam, or drum-shaped rib cam may be employed.

In the above embodiment, both the clamping mechanism 20 and the feed mechanism 30 include the cam mechanisms. However, the mechanisms 20, 30 are not limited to those having the cam mechanisms. One or both of the mechanisms 20, 30 may be a link mechanism that does not have a cam mechanism. Furthermore, a link mechanism without the crank mechanism 12 may be used for the conversion of the reciprocation of the rod 11. For example, a rack and pinion gear may be employed for the conversion of the reciprocation.

In the above embodiment, the transfer mechanism 4 transfers the workpiece in the horizontal direction, which is perpendicular to a direction of the reciprocation of the upper die 3. However, the transfer mechanism 4 is not limited to those which transfer the workpiece in the horizontal direction. The transfer mechanism 4 may be any mechanism as long as it is a mechanism which transfers the workpiece in a direction that crosses a direction of the reciprocation of the movable die. In addition, the transfer mechanism 4 may be a mechanism that performs the combination of the transfer of the workpiece in the direction that crosses the direction of the reciprocation of the movable die, and the transfer of the workpiece in the reciprocation direction.

In the above embodiment, the workpiece is pressed between the lower and upper dies 2, 3 of the die 1. However, the embodiment is not limited to this as long as it is that which performs plastic deformation work on a workpiece between the stationary die and movable die. For example, the invention may be effectively applied to a die for forge processing.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.

Claims

1. A die for performing plastic deformation work upon a workpiece, the die comprising:

a stationary die;

a movable die that is opposed to the stationary die and reciprocatable in a first direction to change a distance between the stationary die and the movable die; and

a transfer mechanism that is configured to transfer the workpiece, upon which the plastic deformation work is performed between the stationary die and the movable die, in a second direction that crosses the first direction, wherein the transfer mechanism includes: a clamp portion that is adapted to clamp and unclamp the workpiece; a synchronizing member that is engaged with the movable die to reciprocate in synchronization with reciprocal movement of the movable die; a clamp-unclamp operation converter that is configured to convert reciprocal movement of the synchronizing member into clamping and unclamping of the workpiece by the clamp portion; and an advance-return operation converter that is configured to convert the reciprocal movement of the synchronizing member into advance-return operation of the clamp portion, whereby the clamp portion advances the workpiece in the second direction and is returned after advancement of the workpiece.

2. The die according to claim 1, wherein:

the transfer mechanism further includes a rotatable shaft and a crank mechanism that is configured to convert the reciprocal movement of the synchronizing member into rotation of the rotatable shaft;

the clamp-unclamp operation converter is configured to convert the rotation of the rotatable shaft into the clamping and unclamping of the workpiece by the clamp portion; and

the advance-return operation converter is configured to convert the rotation of the rotatable shaft into the advance-return operation of the clamp portion.

3. The die according to claim 2, wherein the clamp-unclamp operation converter includes a cam mechanism that is configured to convert the rotation of the rotatable shaft into the clamping and unclamping of the workpiece by the clamp portion.

4. The die according to claim 2, wherein the advance-return operation converter includes a cam mechanism that is configured to convert the rotation of the rotatable shaft into the advance-return operation of the clamp portion.