Extendable device

This extendable device includes: a base member; a first ball screw that is provided to the base member and that rotates according to a driving force supplied from a drive source; a first movable member that is coupled to the base member via the first ball screw and that moves relative to the base member as the first ball screw rotates; a second ball screw that is provided to the first movable member and that rotates as the first movable member moves; a third ball screw that is provided to the first movable member; a transmission mechanism that transmits the rotation of the second ball screw to the third ball screw; and a second movable member that is coupled to the first movable member via the third ball screw and that moves relative to the first movable member as the third ball screw rotates.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is national stage application of International Application No. PCT/JP2019/027719, filed Jul. 12, 2019, which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Application No. 2018-137807, filed Jul. 23, 2018, the entire contents of each are incorporated herein by reference.

FIELD

Various aspects and embodiments of the present disclosure relate to an extendable device.

BACKGROUND

Conventionally, an extendable device that extends and contracts in a height direction or a horizontal direction has been used for substrate conveying robots. For example, in an extendable device that extends and contracts in a height direction, a first ball screw is provided on a fixed support column serving as a base, for example, and a first movable support column is coupled to the fixed support column via a first ball screw. In addition, a second ball screw that is coupled to the first ball screw via a predetermined transmission mechanism is provided to the first movable support column, and a second movable support column is coupled to the first movable support column via a second ball screw. Furthermore, a motor constituting a drive source is attached to the first movable support column. Further, through rotation of the thread of the first ball screw and the threaded shaft of the second ball screw according to a driving force supplied from the motor attached to the first movable support column, the first movable support column moves up and down with respect to the fixed support column, and the second movable support column moves up and down with respect to the first movable support column.

However, in the foregoing technology, because the motor constituting the drive source is attached to the first movable support column, a load including the weight of the motor itself is applied to the motor when the first movable support column and the second movable support column are moving. When the load including the weight of the motor itself is applied to the motor, there is a reduction in the rotational speeds of the first ball screw and second ball screw which rotate according to the driving force supplied from the motor. As a result, there is a reduction in the speeds of movement of the first movable support column and second movable support column, thereby hindering a high-speed extension/contraction operation. Note that, although problems pertaining to an extendable device that extends and contracts in a height direction are described here, similar problems also arise with an extendable device that extends and contracts in a horizontal direction.

SUMMARY

An extendable device includes: a base member; a first ball screw that is provided to the base member and that rotates according to a driving force supplied from a drive source; a first movable member that is coupled to the base member via the first ball screw and that moves relative to the base member as the first ball screw rotates; a second ball screw that is provided to the first movable member and that rotates as the first movable member moves; a third ball screw that is provided to the first movable member; a transmission mechanism that transmits the rotation of the second ball screw to the third ball screw; and a second movable member that is coupled to the first movable member via the third ball screw and that moves relative to the first movable member as the third ball screw rotates.

DESCRIPTION OF EMBODIMENT

Exemplary embodiment of the extendable device disclosed in the present application will be described in detail hereinbelow with reference to the drawings. Note that the same reference signs are assigned to the same or equivalent parts in each of the drawings.

FIG. 1is a perspective view in a case where an extendable device100according to the present embodiment is viewed from the front.FIG. 2is a perspective view in a case where the extendable device100according to the present embodiment is viewed from the rear.FIG. 3is a planar view of the extendable device100according to the present embodiment.FIG. 4is a side elevation of the extendable device100according to the present embodiment.

As illustrated inFIGS. 1 to 4, the extendable device100is coupled via a coupling mechanism102to a motor101which is a drive source separate from the extendable device100, and extends and contracts in a height direction upon receiving a driving force supplied from the motor101. The extendable device100includes a base member110, a first ball screw120, a first movable member130, a second ball screw140, a third ball screw150, a transmission mechanism160, a second movable member170, a first guide mechanism180and a second guide mechanism190.

The base member110is a plate-shaped member that is fixed so as to stand upright on a flat surface such as a floor, for example.

The first ball screw120is provided to the base member110. The first ball screw120is coupled to the motor101via the coupling mechanism102in a state where the motor101is disposed separately from the first movable member130and the second movable member170and rotates according to the driving force supplied from the motor101. Note that the coupling mechanism102includes a pulley that is attached to the output shaft of the motor101, a pulley that is attached to the threaded shaft of the first ball screw120, and a belt that couples together these two pulleys.

The first movable member130is a plate-shaped member that is coupled to the base member110via the first ball screw120. Further, the first movable member130moves relative to the base member110as the first ball screw120rotates. In the present embodiment, the first movable member130moves up and down along the height direction of the base member110. A specific configuration of parts coupling together the base member110and the first movable member130will be described in detail subsequently.

The second ball screw140is provided to the first movable member130and rotates as the first movable member130moves.

The third ball screw150is provided to the first movable member130.

The transmission mechanism160transmits the rotation of the second ball screw140to the third ball screw150.

The second movable member170is a plate-shaped member which is bent in an L shape and has a planar section171for mounting other components such as a conveying arm, for example. The second movable member170is coupled to the first movable member130via the third ball screw150. Further, the second movable member170moves relative to the first movable member130as the third ball screw150rotates. In the present embodiment, the second movable member170moves up and down along the height direction of the first movable member130. A specific configuration of the parts coupling together the first movable member130and the second movable member170will be described in detail subsequently.

Further, the first guide mechanism180guides the movement of the first movable member130with respect to the base member110. More specifically, the first guide mechanism180has a pair of guide rails181and182, and a pair of guide blocks183and184. The pair of guide rails181and182are attached to the base member110and extend in the height direction of the base member110. The pair of guide blocks183and184are attached to the first movable member130and are slidably coupled to the pair of guide rails181and182. As a result of the pair of guide blocks183and184sliding on the pair of guide rails181and182, the first movable member130is guided by the pair of guide rails181and182while moving up and down along the height direction of the base member110.

The second guide mechanism190guides the movement of the second movable member170with respect to the first movable member130. More specifically, the second guide mechanism190has a pair of guide rails191and192, and a pair of guide blocks193and194. The pair of guide rails191and192are attached to the first movable member130and extend in the height direction of the first movable member130. The pair of guide blocks193and194are attached to the second movable member170and are slidably coupled to the pair of guide rails191and192. As a result of the pair of guide blocks193and194sliding on the pair of guide rails191and192, the second movable member170is guided by the pair of guide rails191and192while moving up and down along the height direction of the first movable member130.

Next, the parts coupling together the base member110and the first movable member130will be described in detail with reference toFIG. 5.FIG. 5is a diagram illustrating a configuration of parts coupling together the base member110and the first movable member130, according to the present embodiment. Note thatFIG. 5illustrates a cross-section along line A-A inFIG. 3.

As illustrated inFIG. 5, the first ball screw120provided to the base member110has a threaded shaft121and a nut122. The threaded shaft121is rotatably fixed to the base member110via fixing members121aand121b, and the end of the threaded shaft121is coupled to the output shaft of the motor101via the coupling mechanism102.

The nut122is attached to the threaded shaft121and fixed to the first movable member130via a fixing member122a. Thus, the first movable member130is coupled to the base member110via the first ball screw120(the threaded shaft121and the nut122). Further, the threaded shaft121of the first ball screw120rotates according to the driving force supplied from the motor101, and the nut122causes the first movable member130to move along the threaded shaft121as the threaded shaft121rotates.

Thus, in the extendable device100, the motor101is disposed separately from the first movable member130, and the first movable member130moves relative to the base member110as the first ball screw120rotates using the driving force supplied from the motor101. Hence, when the first movable member130moves, a reduction in the rotational speed of the first ball screw120is suppressed without the load including the weight of the motor101itself acting on the motor101. As a result, a reduction in the speed of movement of the first movable member130is suppressed, thereby enabling a high-speed extension/contraction operation to be realized.

Next, the parts coupling together the first movable member130and the second movable member170will be described in detail with reference toFIGS. 6 to 8.FIGS. 6 to 8are diagrams illustrating configurations of parts coupling together the first movable member130and the second movable member170, according to the present embodiment. Note thatFIG. 6illustrates a cross-section along line B-B inFIG. 3;FIG. 7illustrates a cross-section along line C-C inFIG. 3; andFIG. 8illustrates a cross-section along line D-D inFIG. 4.

As illustrated inFIG. 6, the second ball screw140provided to the first movable member130has a nut141and a threaded shaft142. The nut141is fixed to the base member110via a fixing member141a.

The threaded shaft142is attached to the nut141and rotatably fixed to the first movable member130via the fixing members142aand142b.

As illustrated inFIG. 7, the third ball screw150provided to the first movable member130has a threaded shaft151and a nut152. The threaded shaft151is rotatably fixed to the first movable member130via fixing members151aand151b.

The nut152is attached to the threaded shaft151and fixed to the second movable member170via a fixing member152a. The fixing member152ais inserted into a through-hole131that is formed in an area of the first movable member130which corresponds to the threaded shaft151, thereby coupling together the nut152and the second movable member170. Thus, the second movable member170is coupled to the first movable member130via the third ball screw150(the threaded shaft151and the nut152).

In addition, the threaded shaft142of the second ball screw140and the threaded shaft151of the third ball screw150are coupled to each other by the transmission mechanism160as illustrated inFIG. 8. In other words, the transmission mechanism160has a first pulley161, a second pulley162, and a transmission belt163. The first pulley161is attached to the threaded shaft142of the second ball screw140. The second pulley162is attached to the threaded shaft151of the third ball screw150. The first pulley161and second pulley162are of the same diameter and are coupled to each other by the transmission belt163. When the first movable member130moves, the threaded shaft142of the second ball screw140rotates, and the first pulley161rotates as the threaded shaft142of the second ball screw140rotates. The rotation of the first pulley161is transmitted by the transmission belt163to the second pulley162. The second pulley162rotates as a result of the rotation of the first pulley161being transmitted to the second pulley162. Further, the threaded shaft151of the third ball screw150rotates as the second pulley162rotates, and the nut152causes the second movable member170to move along the threaded shaft151. Here, the first pulley161and the second pulley162are of the same diameter, and the speed of movement of the first movable member130and the speed of movement of the second movable member170are identical.

Thus, in the extendable device100, the motor101is disposed separately from the second movable member170, and the second movable member170moves relative to the first movable member130as the third ball screw150rotates on the basis of the movement of the first movable member130. Hence, when the second movable member170moves, a reduction in the rotational speed of the third ball screw150is suppressed without the load including the weight of the motor101itself acting on the motor101. As a result, a reduction in the speed of movement of the second movable member170is suppressed, thereby enabling a high-speed extension/contraction operation to be realized.

According to the present embodiment hereinabove, the first movable member130is made to move relative to the base member110as the first ball screw120rotates using the driving force supplied from the motor101which is separate from the first movable member130. Furthermore, according to the present embodiment, the rotation of the second ball screw140, which moves together with the movement of the first movable member130, is transmitted to the third ball screw150by the transmission mechanism160, and the second movable member170is made to move relative to the first movable member130as the third ball screw150rotates. Hence, when the first movable member130and the second movable member170move, a reduction in the rotational speeds of the first ball screw120and third ball screw150is suppressed without the load including the weight of the motor101itself acting on the motor101. As a result, a reduction in the speeds of movement of the first movable member130and the second movable member170is suppressed, thereby enabling a high-speed extension/contraction operation to be realized.

In addition, according to the present embodiment, because the motor101does not move, the burden that acts on the power supply cable connected to the motor101can be reduced and the lifespan of the power supply cable can be extended.

Furthermore, in a case where the extendable device100according to the present embodiment is disposed in a vacuum device, because the motor101can be disposed separate from the extendable device100, it is not necessary for the motor101to be disposed inside the vacuum device. It is therefore possible to place the motor101in an atmospheric environment.

Moreover, according to the present embodiment, because the first movable member130is coupled to the base member110and the second movable member170is coupled to the first movable member130, the stroke length can be made large.

Note that, although the speed of movement of the first movable member130and the speed of movement of the second movable member170are identical in the foregoing embodiment, the ratio of the speed of movement of the second movable member170to the speed of movement of the first movable member130may be modified. That is, the first pulley161and second pulley162which are illustrated inFIG. 8may also be of different diameters. In addition, the threaded shaft142of the second ball screw140illustrated inFIG. 8and the threaded shaft151of the third ball screw150may also have different thread groove pitches.

Moreover, although the extendable device100extends and contracts in the height direction in the foregoing embodiment, same may also extend and contract in the horizontal direction. In this case, the base member110illustrated inFIG. 1is fixed parallel to a flat surface such as a floor, for example.

One aspect of the disclosed extendable device affords the advantageous effect of enabling a high-speed extension/contraction operation to be realized.