Workpiece conveying device

It is a subject to provide a workpiece conveying device capable of linearly conveying a workpiece with a light-weight and simple configuration. The present invention is a workpiece conveying device 100 for conveying a workpiece W, the workpiece conveying device 100 comprising a main body portion 10; a rail portion 1 mounted to an upper portion of the main body portion 10; a guide portion 1a slidable along the rail portion 1; an arm 3 in which a first pivotally attaching portion 3b at the upper end thereof is pivotally attached to the guide portion 1a; a holding means 4 which is mounted to a second shall 3a at a lower end of the arm 3 and which can hold the workpiece W; an auxiliary arm 20 mounted to a first shaft 2b of the main body portion 10 to be rotatable; a slider portion 2a slidable along the auxiliary arm 20; and servomotors for driving the auxiliary arm 20, wherein a second pivotally attaching portion 3c at approximately a center of the arm 3 is pivotally attached to the slider portion 2a.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage of International Application No. PCT/JP2013/006274, which was filed on Oct. 23, 2013, and which claims priority to JP 2012-234222 which was filed on Oct. 23, 2012, and which are both herein incorporated by reference.

TECHNICAL FIELD

The present invention relates to a workpiece conveying device, and more particularly to a workpiece device capable of linearly conveying a workpiece with a light-weight and simply configuration.

BACKGROUND ART

Workpiece conveying devices are used for conveying workpieces in tandem press lines for successively pressing workpieces.

There are various workpiece conveying devices of robot style provided with arms.

For instance, there is known a workpiece conveying device comprising a beam built between adjoining press machines, a carrier provided to be freely movable along the beam, a cradle table supported by the carrier and being driven to swing along a workpiece conveying direction, and a crossbar suspending and supporting a workpiece via vacuum cups holding the workpiece in a freely detachable manner, wherein a relative distance between a swing center of the cradle table and the crossbar is arranged to be variable by providing a field lever at the cradle table via a linear moving mechanism (see, for instance, Patent Literatures 2 and 3).

Further, there is known a workpiece conveying device comprising a workpiece holding means which holds a workpiece, a carrier disposed between adjoining presses and being linearly movable in a direction orthogonal to a workpiece conveying direction by means of a driving mechanism, and a swinging body which central axis of swinging is provided at the carrier and which is driven to swing along the work conveying direction by means of a swinging mechanism (for instance, Patent Literature 4).

In this workpiece conveying device, there is provided a so-called Scott Russell mechanism in which an inter-axial distance of both ends of a second link is defined to be half of an inter-axial distance of both ends of a first link, and in which one end of the second link is coupled to a center of the axis interval of both ends of the first link while the other end of the second link is positioned on an extension of a moving line of another end of the first link.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In the workpiece conveying devices recited in the above Patent Literatures 1 to 3, while the relative distance between the center of the rotation supporting axis and the crossbar is varied via the linear moving mechanism, there is a drawback in that complicated adjustments are necessary for linearly conveying a workpiece.

Moreover, since the linear moving mechanism is of large weight, large load is applied to the device due to inertial force and other factors when the carrier is moved along the beam or when the cradle table is rotated which might cause a breakdown.

Further, due to its large weight, it is not quite superior in energy efficiency.

In the workpiece conveying device recited in the above Patent Literature 4, there is a drawback in that the device becomes excessively large because it requires a lift driving means which drives a supporting member in the vertical direction in addition to the driving means which drives the first link and the second link.

The present invention has been made in view of the above circumstances, and it is an object thereof to provide a workpiece conveying device capable of linearly conveying a workpiece with a light-weight and simply configuration.

Solution to Problems

By performing earnest considerations for solving the above problems, the inventors of the present invention have found that the above problem can be solved by making the arm to be slidable along a rail portion via a guide portion and further by making a slider portion to which the arm is pivotally attached to be slidable along an auxiliary arm, and have come to complete the present invention.

The present invention resides (1) in a workpiece conveying device for conveying a workpiece, the workpiece conveying device comprising a main body portion; a rail portion provided to extend at an upper portion of the main body portion; a guide portion slidable along the rail portion; an arm which upper end is pivotally attached to the guide portion by means of a first pivotally attaching portion; a holding means which is mounted to a second shaft at a lower end of the arm and which can hold the workpiece; an auxiliary arm mounted to a first shaft of the main body portion to be rotatable; and a slider portion slidable along the auxiliary arm, wherein approximately a center of the arm is pivotally attached to the slider portion by means of a second pivotally attaching portion.

The present invention resides (2) in the workpiece conveying device according to above (1) wherein the second pivotally attaching portion is provided closer to the first pivotally attaching portion side than a central portion with respect to a longitudinal direction of the arm.

The present invention resides (3) in the workpiece conveying device according to above (1) or (2) wherein a ratio of a distance from the first pivotally attaching portion to the second pivotally attaching portion and a distance from the second shaft to the second pivotally attaching portion is 1:1.2 to 2.

The present invention resides (4) in the workpiece conveying device according to any one of above (1) to (3) wherein a ratio of a distance from the first shaft to the second pivotally attaching portion and a distance from the first pivotally attaching portion to the second shaft is 1:2 to 4.

The present invention resides (5) in the workpiece conveying device according to any one of above (1) to (4) wherein a belt portion which slides along a longitudinal direction of the auxiliary arm is extended at the auxiliary arm, and wherein the slider portion is fixed at the belt portion.

The present invention resides (6) in the workpiece conveying device according to any one of above (1) to (5) wherein all of rotation of the holding means, rotation of the auxiliary arm and sliding of the slider portion is performed by driving a servomotor.

The present invention resides (7) in the workpiece conveying device according to any one of above (1) to (6) wherein the holding means is comprised of a crossbar connected to the arm and suction portions mounted to the crossbar.

The present invention resides (8) in the workpiece conveying device according to any one of above (1) to (7) which is used as a device carrying a workpiece in and out with respect to a press machine and which is mounted to a post of the press machine.

Advantageous Effects of Invention

In the workpiece conveying device of the present invention, it is possible to adjust heights of workpieces at the time of conveying workpieces by sliding the guide portion to which the arm is mounted along the rail portion. With this arrangement, it is possible to convey a workpiece linearly.

Further, in the workpiece conveying device, by sliding the slider portion to which the arm is pivotally attached at the second pivotally attaching portion along the auxiliary arm, the auxiliary arm can support the arm without interfering linear conveyance of a workpiece. With this arrangement, it is possible to linearly convey also a workpiece of relatively large weight.

Moreover, since the workpiece conveying device is of simple and light-weight configuration, it is superior in energy efficiency, installation thereof easy, and it requires no space.

In the workpiece conveying device of the present invention, the device can be made compact since the second pivotally attaching portion is provided closer to the first pivotally attaching portion side than the central position with respect to the longitudinal direction of the arm. Particularly, the device can be made more compact when the ratio of the distance from the first pivotally attaching portion to the second pivotally attaching portion and the distance from the second shaft to the second pivotally attaching portion is 1:1.2 to 2, and it is also possible to reduce energy costs necessary for conveyance.

The size of the device can be made more compact when the ratio of the distance from the first shaft to the second pivotally attaching portion and the distance from the first pivotally attaching portion to the second shaft is 1:2 to 4.

In the workpiece conveying device of the present invention, the belt portion which slides along the longitudinal direction of the auxiliary arm is extended at the auxiliary arm, and when the slider portion is fixed at the belt portion, the belt portion slides in a state in which the slider portion is supported at the belt portion, and it can endure larger weight loads.

In the workpiece conveying device of the present invention, when all of rotation of the holding means, rotation of the auxiliary arm and sliding of the slider portion is performed by driving servomotors, it is possible to perform control at high accuracy, and since no space is required, the configuration might be simpler when compared to other driving sources.

In the workpiece conveying device of the present invention, when the holding means is comprised of the crossbar connected to the arm and the suction portions mounted to the crossbar, it is possible to suck and hold a workpiece also in case it is of a relatively large workpiece.

The workpiece conveying device of the present invention can be used as a device carrying a workpiece in and out with respect to a press machine by attaching the same to a post of the press machine. In case of a tandem press line, the entire line can be made compact.

Since the workpiece can be conveyed linearly, it is possible to carry the workpiece in and out quickly and efficiently.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be explained in details hereinbelow with reference to drawings as necessary. In this respect, identical elements are marked with identical reference signs, and duplicated explanations will be omitted. Further, unless specified otherwise, positional relationships of top and bottom or right and left are based on the positional relationships as shown in the drawings. Moreover, dimensional ratios of the drawings are not limited to the illustrated ratios.

FIG. 1is a front view showing one example of a workpiece conveying device according to the present embodiment.

As shown inFIG. 1, the workpiece conveying device100according to the present embodiment comprises a main body portion10; a rail portion1provided to extend at an upper portion of the main body portion10; a guide portion1aslidable along the rail portion1; an arm3which upper end is pivotally attached to the guide portion1aby means of a first pivotally attaching portion3b; a holding means4which is mounted to a second shaft3aat a lower end of the arm3and which can hold a workpiece W; an auxiliary arm20mounted to a first shaft2bof the main body portion10to be rotatable; and a slider portion2aslidable along the auxiliary arm20.

The slider portion2ais pivotally attached to approximately the center of the arm3by means of a second pivotally attaching portion3c.

In this manner, the workpiece conveying device100is of light-weight and simple configuration.

In the workpiece conveying device100, the workpiece W is conveyed by holding the workpiece W by means of the holding means4and by rotating the arm3to which the holding means4is mounted at the first pivotally attaching portion3b.

At this time, the guide portion in pivotally attached to the arm3by means of the first pivotally attaching portion3bslides along the rail portion1in the vertical direction, and simultaneously therewith, the slider portion2apivotally attached to approximately the center of the arm3by means of the second pivotally attaching portion3cslides in the longitudinal direction of the auxiliary arm20. In this respect, details of these movements will be described later. With this arrangement, it is possible to reliably hold the workpiece W while the workpiece W can be conveyed linearly with a compact configuration.

The workpiece conveying device100will hereinafter be explained in further details.

In the workpiece conveying device100, the rail portion1extending linearly in the longitudinal direction (vertical direction) of the main body portion10is provided to extend at an upper portion of the main body portion10, and the guide portion1ais mounted to the rail portion1to be freely slidable in the vertical direction along the rail portion1.

The guide portion1ais pivotally attached to the upper end of the arm3by means of the first pivotally attaching portion3b.

Accordingly, the upper end of the arm3slides in the vertical direction along the rail portion1integrally with the guide portion1a. With this arrangement, it is possible to adjust heights of workpieces W at the time of conveying workpieces W.

The auxiliary arm20is mounted to the main body portion10in a rotatable manner.

Here, the auxiliary arm20is mounted to the main body portion10just below the rail portion1and being apart therefrom by a certain distance. With this arrangement, it is possible to make the auxiliary arm20more compact and to reduce the moving distance of the slider portion2at the time of conveying a workpiece. Namely, it is possible to make the slider portion2asmoothly follow movements of the arm3while movements of the slider portion2aitself are relatively limited.

FIG. 2is a side view showing one example of a workpiece conveying device according to the present embodiment.

As shown inFIG. 2, in the workpiece conveying device100, a servomotor (hereinafter referred to as “first servomotor” for the sake of convenience)7aand a reduction gear8acoupled to the first servomotor are mounted to the rear surface of the rail portion1. Therefore, by suitably selecting reduction ratios, the first servomotor7acan suppress torque of a motor shaft.

Here, the auxiliary arm20rotates around the first shaft2bprovided at the main body portion10. Further, the first servomotor7ais coupled to the first shaft2bvia the reduction gear8a. Therefore, the auxiliary arm20is arranged to rotate around the first shaft2bof the main body portion10as indicated by arrow A based on driving of the first servomotor7a.

Returning toFIG. 1, the main body portion10is arranged to be mounted to a post of a press machine as it will be described later. Namely, the workpiece conveying device100can be mounted to a post P1of a press machine via the main body portion10(seeFIG. 5).

The arm3is pivotally attached to the guide portion1aat its upper end by means of the first pivotally attaching portion3band is made to rotate largely around the first pivotally attaching portion3b.

Further, approximately the center of the arm3is pivotally attached to the slider portion2aby means of the second pivotally attaching portion3c.

Moreover, the holding means4capable of holding a workpiece W is mounted to the second shaft3aat the lower end of the arm3.

Here, the second pivotally attaching portion3cis provided to lean closer to the first pivotally attaching portion3bside (guide portion1aside) than the central portion with respect to the longitudinal direction of the arm3. With this arrangement, the length of the auxiliary arm20can be reduced, and the device can be made more compact.

At this time, it is preferable that the ratio of the distance H1from the first pivotally attaching portion3bto the second pivotally attaching portion3cand the distance H2from the second shaft3ato the second pivotally attaching portion3c(H1:H2) is 1:1.2 to 2. In this case, the device can be made more compact, and it is also possible to reduce energy costs necessary for conveyance.

Further, it is preferable that the ratio of the distance H3from the first shaft2bto the second pivotally attaching portion3cand the distance (H1+H2) from the first pivotally attaching portion3bto the second shaft3b(H3:H1+H2) is 1:2 to 4. In this case, the size of the device can be made more compact.

The holding means4comprises the crossbar4acoupled to the second shaft3aat the lower end of the arm and a plurality of suction portions4bmounted to the crossbar4a. Therefore, it is possible to suck and hold a workpiece W also in case of a relatively large workpiece W.

FIG. 3is a top view showing the holding means in the workpiece conveying device according to the present embodiment.

As shown inFIG. 3, the suction portions4beach comprised of a pair of right and left vacuum cups are mounted at eight spots of the crossbar4ain the holding means4.

Each of the suction portions4bsucks and holds a planar portion of a workpiece W by sucking its interior. In this respect, it is also possible that each of the suction portions4bsucks and holds the workpiece W independently from each other. In this case, it is possible to suitably select suction portions4bto be used depending on shapes and sizes of workpieces W.

In the holding means4, a servomotor7c(hereinafter referred to as “second servomotor” for the sake of convenience) is coupled to the second shaft3a(seeFIG. 2).

Accordingly, the crossbar4ais made to rotate based on driving of the second servomotor7c. In this respect, the crossbar4arotates with the suction portions4bcontinuously facing directly downward corresponding to the position of the rotating arm3.

FIG. 4is an enlarged front view showing the auxiliary arm in the workpiece conveying device according to the present embodiment.

As shown inFIG. 4, in the workpiece conveying device100, the belt portion2which slides along the longitudinal direction of the auxiliary arm20is extended at the auxiliary arm20, and the slider portion2ais fixed at the belt portion2.

More specifically, at the auxiliary arm20, the belt portion2is extended in the longitudinal direction via a follower pulley9aand a drive pulley9b, and the slider portion2ais fixed to the belt portion2.

Further, a servomotor7b(hereinafter referred to as “third servomotor” for the sake of convenience) for driving the follower pulley9bis mounted to the auxiliary arm20via a reduction gear8b. Therefore, by suitably selecting reduction ratios, the third servomotor7bcan suppress torque of the motor shaft.

In the auxiliary arm20, the drive pulley9bmoves based on driving of the third servomotor7b, and the belt portion2slides along the longitudinal direction of the auxiliary arm20.

At this time, since the slider portion2ais fixed to the belt portion2, the slider portion2awill also slide along the longitudinal direction of the auxiliary arm20integrally with the belt portion2. In this respect, the arm3is pivotally attached to the slider portion2aby means of the second pivotally attaching portion3cas described above.

In the workpiece conveying device100, the arm3rotates at the first pivotally attaching portion3b, through the cooperation of the first servomotor7afor driving the auxiliary arm20and the third servomotor7bfor driving the slider portion2a.

In the workpiece conveying device100, by sliding the slider portion2apivotally attached to the arm3along the auxiliary arm20mounted to the main body portion10in a rotatable manner, the auxiliary arm20supports the arm3via the slider portion2awhile it does not interfere linear conveyance of the workpiece W. With this arrangement, it is possible to linearly convey also a workpiece W of relatively large weight as it will be described later.

In the workpiece conveying device100, since all of rotation of the holding means4, rotation of the auxiliary arm20and sliding of the slider portion2ais performed by driving the servomotors as described above, the configuration does not require space and be even simpler.

The workpiece conveying device100according to the present embodiment is preferably used, for instance, as a device for carrying a workpiece in and out with respect to a press machine and which is mounted to a post of the press machine.

FIG. 5is a schematic perspective view showing a press machine to which the workpiece conveying device according to the present embodiment is mounted. In this respect, detailed portions of the press machine will be omitted.

As shown inFIG. 5, the press machine P is arranged in that the main body portion10of the workpiece conveying device100is mounted to a post P1. Namely, since the workpiece conveying device100according to the present embodiment is of light-weight and simple configuration and is space-saving, it can be installed in a small space.

In the press machine P, a workpiece after pressing is carried out by the workpiece conveying device100. In this respect, it is, of course, also possible to carry a workpiece in before pressing into the press machine.

For instance, also in case a plurality of press machines P is aligned to comprise a tandem press line, the workpiece conveying devices100will not require large spaces and the entire line can be made compact.

Moreover, as described above, since the workpiece conveying device100can convey a workpiece linearly, it is possible to carry the workpiece in and out quickly and efficiently in the press machine P.

Next, a workpiece conveying method using the workpiece conveying device100will be explained.

FIGS. 6(a)toFIG. 6(f)are explanatory views for explaining tracks of the lower end (base portion of the second shaft3a) of the arm when a workpiece is conveyed using the workpiece conveying device according to the present embodiment. In this respect, detailed descriptions of the holding means4are omitted for the sake of convenience.

As shown inFIG. 6(a), the lower end of the arm3holds a workpiece (not shown) at position A via the holding means. At this time, the guide portion1ais positioned on the lowermost side of the rail portion1and the slider portion2ais positioned closer to the upper side of the auxiliary arm20.

Then, the guide portion1ais moved upward up to approximately the center of the rail portion1and the slider portion2ais moved to the uppermost side of the auxiliary arm20. Then, the arm3will move upward while maintaining a predetermined angle as shown inFIG. 6(b)and the lower end of the arm3reaches position B. With this arrangement, the workpiece (not shown) is lifted up.

Next, the slider portion2amaintains the state in which it is at the uppermost position of the auxiliary arm20and the guide portion1ais moved to the uppermost side of the rail portion1. Then, the arm3and the auxiliary arm20rotate to be aligned on the same line as shown inFIG. 6(c). Consequently, the lower end of the arm3moves rightward and reaches position C. At this time, the guide portion1a, the rail portion1, the slider portion2a, the auxiliary arm20and the arm3will overlap on the same line.

Next, the slider portion2amaintains the state in which it is at the uppermost position of the auxiliary arm20and the guide portion1ais moved downward up to approximately the center of the rail portion1. Then, the arm3and the auxiliary arm20rotate as shown inFIG. 6(d)and the lower end of the arm3moves further rightward and reaches position D.

Next, the guide portion1ais moved to the lowermost side of the rail portion1and the slider portion2ais moved to a position closer to the upper side of the auxiliary arm20from the uppermost position of the auxiliary arm20. Then, the arm3moves downward in a state in which it maintains the predetermined angle as shown inFIG. 6(e)and the lower end of the arm3reaches position E. Holding of the workpiece (not shown) is then released via the holding means4.

Conveyance of a workpiece is performed in this manner.

In this respect, after conveying the workpiece, the guide portion1ais moved to approximately center of the rail portion1and the slider portion2ais moved to the lowermost side of the auxiliary arm20. Then, the arm3and the auxiliary arm20rotate as shown inFIG. 6(f)and the lower end of the arm3moves leftward and reaches position F. At this time, the guide portion1a, the rail portion1, the slider portion2a, the auxiliary arm20and the arm3will repeatedly be overlapped on the same line.

Then, the guide portion1ais moved to the lowermost side of the rail portion1and the slider portion2ais moved from the lowermost position of the auxiliary arm20to a position closer to the upper side of the auxiliary arm20. Then, the arm3and the auxiliary arm20rotate, the second shaft3amoves leftward, and the lower end of the arm3reaches the position A as shown inFIG. 6(a).

In the workpiece conveying method using the workpiece conveying device100, it is possible to linearly convey a workpiece by sliding the guide portion1apivotally attached to the arm3along the rail portion1on one hand and by sliding the slider portion2apivotally attached to the arm3along the auxiliary arm20on the other hand.

When a workpiece is sucked and held, the workpiece can be linearly conveyed in the lateral direction in a state in which it is lifted upward, and when no workpiece is sucked and held, the second shaft3aat the lower end of the arm3can be moved linearly in the lateral direction without moving it upward. Namely, it is possible to move the second shaft3ain the lateral direction via two types of paths.

While a preferred embodiment of the present invention has been explained above, the present invention is not to be limited to the above embodiment.

For instance, while the holding means4comprising the crossbar4aconnected to the second shaft3aat the lower end of the arm3and suction portions4bmounted to the crossbar4ais used as a means which holds a workpiece W in the workpiece conveying device100according to the present embodiment, the present invention is not limited to this, and it is also possible to employ a gripper or the like.

Further, while suction portions4bcomprised of a pair of right and left vacuum cups are mounted to the crossbar4aat eight spots, spots and numbers of mounting the suction portions4bare not limited to this.

While one end of the crossbar4ais coupled to the second shaft3aat the lower end of the arm3in the workpiece conveying device100according to the present embodiment, it is also possible that a pair of workpiece conveying devices100is coupled to both ends of the crossbar. Namely, it is also possible that a pair of workpiece conveying devices100is coupled via the crossbar.

While the slider portion2ais mounted to the auxiliary arm20via the belt portion2in the workpiece conveying device100according to the present embodiment, the present invention is not limited to this configuration.

For instance, it is also possible to provide a rail at the auxiliary arm20and to make the slider portion slide along this rail or to move the slider itself using wires or the like.

While all of rotation of the holding means4, rotation of the auxiliary arm20and the sliding of the slider portion2ais performed through driving servomotors in the workpiece conveying device100according to the present embodiment, the present invention is not limited to this, and it might also be driving using invertor motors or the like.

On the other hand, it is also possible to perform sliding of the guide portion1aby driving a servomotor instead of rotation of the auxiliary arm20.

In the workpiece conveying device100according to the present embodiment, mounting of the reduction gears to the first servomotor, the second servomotor and the third servomotor is arbitrary.

INDUSTRIAL APPLICABILITY

The workpiece conveying device according to the present invention is preferably used as a workpiece conveying device for conveying a workpiece used, for instance, for press working.

According to the workpiece conveying device according to the present invention, a workpiece can be conveyed linearly with a light-weight and simple configuration.

REFERENCE SIGNS LIST