Work machine

A frame structure of a work machine includes a left frame in which a first left rail of a first guide device is provided at a lower portion thereof; a right frame in which a second right rail of a second guide device is provided at a lower portion thereof; a center frame disposed between the left frame and the right frame and in which a first right rail of the first guide device and a second left rail of the second guide device are provided at a lower portion thereof; a front frame connecting a pair of front columns together and also connecting respective front ends of the left frame, the right frame, and the center frame; and a rear frame connecting a pair of rear columns together and also connecting respective rear ends of the left frame, the right frame, and the center frame.

TECHNICAL FIELD

The present application relates to a work machine.

BACKGROUND ART

Patent literature 1 discloses, as a work machine for performing various types of work by moving a head, a component mounter for mounting electronic components on circuit boards. Among guide devices for moving a head in such a work machine, there are guide devices which are of a suspension type in which a moving body of the guide device is supported by being suspended from a rail. Such suspension type guide devices have a configuration like one described, for example, in patent literature 1, in which a pair of rails and a drive device for applying a driving force to the moving body are disposed on a frame spanning a front column and a rear column.

PATENT LITERATURE

BRIEF SUMMARY

Technical Problem

For work machines like the one described above, there is a demand to improve the working accuracy by reducing the effect of vibrations caused by the moving head. In addition, in order to improve the productivity per installation area, it is desirable for the work machines to be made smaller. An object of the present description is to provide a work machine which improves the rigidity of the entire machine to reduce the effect of vibrations caused by a moving head thereof.

Solution to Problem

The present description discloses a first work machine including: a base; a pair of front columns provided on left and right sides of a front portion of the base; a pair of rear columns provided on left and right sides of a rear portion of the base; a frame structure spanning the pair of front columns and the pair of rear columns; a first head and a second head both configured to perform predetermined work in movable ranges defined so as not to overlap each other above the base; a first guide device provided on the frame structure on a left side of the center of the base in a left-right direction thereof and configured to allow the first head to move in a front-rear direction of the base, and a second guide device provided on the frame structure on a right side of the center of the base in the left-right direction thereof and configured to allow the second head to move in the front-rear direction of the base; wherein the first guide device further comprises: a first left rail and a first right rail both extending in the front-rear direction of the base, the first left rail and the first right rail being parallel, and a first moving body provided so as to move in the front-rear direction of the base while being suspended from the first left rail and the first right rail and supporting the first head; wherein the second guide device further comprises:

a second left rail and a second right rail both extending in the front-rear direction of the base, the second left rail and the second right rail being parallel, and a second moving body provided so as to move in the front-rear direction of the base while being suspended from the second left rail and the second right rail and supporting the second head; and wherein the frame structure further comprises: a left frame in which the first left rail of the first guide device is provided at a lower portion thereof; a right frame in which the second right rail of the second guide device is provided at a lower portion thereof; a center frame, being disposed between the left frame and the right frame, in which the first right rail of the first guide device and the second left rail of the second guide device are provided at a lower portion thereof; a front frame connecting the pair of front columns together and also connecting respective front ends of the left frame, the right frame, and the center frame together, and a rear frame connecting the pair of rear columns together and also connecting respective rear ends of the left frame, the right frame, and the center frame together.

The present description discloses a second work machine including: a base; a pair of front columns provided on left and right sides of a front portion of the base; a pair of rear columns provided on left and right sides of a rear portion of the base; a frame structure spanning the pair of front columns and the pair of rear columns; a first head configured to perform predetermined work in a movable range defined above the base, and a first guide device provided on the frame structure and configured to allow the first head to move in a front-rear direction of the base, wherein the first guide device further comprises: a first left rail and a first right rail both extending in the front-rear direction of the base, the first left rail and the first right rail being parallel, and a first moving body, being provided so as to move in the front-rear direction of the base, while being suspended from the first left rail and the first right rail, and supporting the first head, wherein the frame structure further comprises: a left frame in which the first left rail of the first guide device is provided at a lower portion thereof; a right frame in which the first right rail of the first guide device is provided at a lower portion thereof; a front frame connecting the pair of front columns together and also connecting respective front ends of the left frame and the right frame together, and a rear frame connecting the pair of rear columns together and also connecting respective rear ends of the left frame and the right frame together; and wherein the first left rail and the first right rail of the first guide device are disposed respectively in ranges where the movable range of the first head overlaps left and right support ranges defined in a left-right direction of the base where the pair of front columns and the pair of rear columns are connected to the frame structure.

Advantageous Effects

With the configuration of the first work machine, the pair of front columns and the pair of rear columns are connected together by the frame structure including the left and right frames, the front and rear frames, and the center frame. As a result, the work machine improves the overall rigidity of the work machine with the structural rigidity of the frame structure while maintaining the overall external dimensions of the work machine. Thus, the frequency of vibrations caused in association with movement of the first head and the second head can be increased, which facilitates suppressing and controlling the vibrations. As a result, the effect of the vibrations can be reduced to thereby improve the working efficiency of the work machine. In addition, the frame structure supports the first guide device and the second guide device, which are both suspended, as a result of the rails being provided individually at the lower portions of the left frame, the right frame, and the center frame. As a result, the work machine can reliably bear the loads of the first guide device and the second guide device and suppress the occurrence of vibrations that would otherwise be caused in association with movement of the first head and the second head.

With the configuration of the second work machine, the pair of front columns and the pair of rear columns are connected together by the frame structure including the left and right frames and the front and rear frames. As a result, the work machine improves the overall rigidity of the work machine with the structural rigidity of the frame structure while maintaining the overall external dimensions of the work machine. Thus, since the frequency of the vibrations caused in association with movement of the first head can be increased, which facilitates suppressing and controlling the vibrations As a result, the effect of the vibrations can be reduced to thereby improve the working efficiency of the work machine. The frame structure supports the first guide device, which is suspended, with the individual rails provided at the lower portions of the left frame and the right frame. As a result, the work machine can reliably bear the load of the first guide device and can suppress the occurrence of vibrations that would otherwise be caused in association with movement of the first head.

DESCRIPTION OF EMBODIMENTS

1. First Embodiment

Hereinafter, an embodiment of a work machine will be described by reference to the drawings. A work machine performs various types of work by moving a head. In this embodiment, the work machine is described as a component mounter. The component mounter is a production device for producing board products by mounting electronic components in predetermined mounting positions on circuit boards. Hereinafter, a “circuit board” will simply be referred to as a “board”, and an electronic component will simply be referred to as a “component”.

1-1. Configuration of Component Mounter1

As illustrated inFIG. 1, multiple component mounters1are provided to be aligned side by side in, for example, a direction in which boards Bd are conveyed, constituting a production line for producing board products. Each component mounter1includes base2, board conveyance device10, component supply device20, two component transfer devices30, front column member60, rear column member70, frame structure80, control device90, and the like.

In the following description, a horizontal width direction of component mounter1(a direction directed from an upper left to a lower right inFIG. 1) is referred to as an X-axis direction or a left-right direction. A horizontal depth direction of component mounter1(a direction directed from a lower left to an upper right inFIG. 1) is referred to as a Y-axis direction or a front-rear direction. A vertical direction perpendicular to an X-axis and a Y-axis (an up-down direction inFIG. 1) is referred to as a Z-axis direction or an up-down direction.

Board conveyance device10is placed on base2and is made up of a belt conveyor or the like. Board conveyance device10conveys boards Bd sequentially in a conveyance direction (in an X-axis direction in this embodiment). Board conveyance device10locates board Bd in a predetermined position inside component mounter1. Then, after component mounter1has performed a mounting process on board Bd, board conveyance device10conveys board Bd so processed outside of component mounter1.

Component supply device20is placed on base2and supplies components to be mounted on boards Bd. Component supply device20includes multiple feeders21that are set individually in multiple slots disposed side by side in the X-axis direction in a replaceable fashion. A carrier tape installing with a number of components is wound around supply reel22and is loaded in each feeder21. Feeder21feeds out the carrier tape to supply a component to a supply position located at a distal end of feeder21so that the component can be picked up there.

Each of two component transfer devices30is used for a mounting process of picking up a component supplied by component supply device20and then mounting the component on board Bd. In this embodiment, two component transfer devices30are disposed to be aligned side by side in the left-right direction of component mounter1and are supported by frame structure80. The detailed configuration of two component transfer devices30will be described later.

As illustrated inFIG. 2, front column member60includes pair of front columns61and connecting member62. Pair of front columns61are provided at left and right sides of a front portion of base2. In this embodiment, pair of front columns61are connected together at front end portions by connecting member62extending in a left-right direction of base2to form an integral portal-like structure.

Rear column member70is disposed separated from front column member60in the front-rear direction of base2. Rear column member70includes pair of rear columns71and a connecting member72. Pair of rear columns71are provided at left and right sides of a rear portion of base2. In this embodiment, pair of rear columns71are connected together by connecting member72extending in the left-right direction of base2to form an integral portal-like structure.

Frame structure80spans pair of front columns61and pair of rear columns71. Frame structure80is a strength member configured not only to support two component transfer devices30but also to connect front column member60and rear column member70together to thereby improve the overall rigidity of the work machine. A detailed configuration of frame structure80will be described later.

Control device90is made up mainly of CPU, various memories, and a control circuit. Control device90executes a mounting process of mounting components on boards Bd. The mounting process is executed based on a control program and constitutes a pick and place cycle of picking up a component supplied by component supply device20and transferring the component to a predetermined mounting position on board Bd repeatedly multiple times.

In addition, in the mounting process, when controlling the operation of mounting heads35, which will be described later, control device90receives information outputted from various sensors provided in component mounter1, and the result of a recognition process by image processing or the like. Then, the control device sends control signals to component transfer devices30based on the control program, information from the various sensors, and the results of the various recognition processes. As a result, positions and angles of components held by mounting heads35are controlled.

To improve further the accuracy of the mounting process, control device90suppresses and controls vibrations generated in association with the operation of mounting heads35. For example, when moving mounting head35to a position above a mounting position while executing the mounting process, control device90calculates the time it takes until the amplitude of vibration generated in association with the movement of mounting head35is dampened to be equal to or less than an allowable value based on a starting position and an ending position of the movement of mounting head35, a traveling speed of mounting head35, a mass of the moving member, and the like. Then, after having waited for the calculated dampening time to elapse, control device90lowers suction nozzle36holding a component and mounts the component in a predetermined mounting position on board Bd. An improvement in the accuracy of the mounting process is achieved by executing the mounting process while controlling the vibration in the way described above.

Additionally, since vibrations generated during execution of a mounting process by component mounter1generate a waiting time corresponding to a dampening time, the vibrations constitute a cause that extends the cycle time necessary for the mounting process. Here, the frequency of vibrations generated in component mounter1tends to increase as the rigidities of the constituent members thereof increase, and the dampening time decreases as the frequency increases. By increasing the rigidities of the constituent members of component mounter1, a waiting time attributed to vibrations generated in a mounting process can be expected to be shortened. Therefore, in component mounter1, it is desirable that frame structure80is highly rigid, frame structure80being a frame structure connecting front column member60and rear column member70provided on base2and supporting two component transfer devices30.

1-2. Detailed Configuration of Component Transfer Device30

As illustrated inFIG. 2, component transfer device30includes Y-axis guide device31, linear motor32, X-axis guide device33, and mounting head35. Y-axis guide device31moves mounting head35in a front-rear direction (a Y-axis direction) of base2. Y-axis guide device31includes pair of guide rails311, four guide blocks312, and Y-axis moving body313. Pair of guide rails311is made up of left rail311L and right rail311R that both extend in the front-rear direction of base2and are disposed parallel to each other.

Four guide blocks312are each in slidable engagement with pair of guide rails311. Y-axis moving body313is fixed to lower portions of four guide blocks312. As a result, Y-axis moving body313can move in the front-rear direction of base2while being suspended from left rail311L and right rail311R. As described above, Y-axis guide device31is of a suspension type in which Y-axis moving body313is supported while being suspended from pair of guide rails311, allowing a large movable range to be ensured in a left-right direction.

Linear motor32includes motor shaft321, motor block322, and cooling device323. Motor shaft321is a fixed member that is disposed parallel to pair of guide rails311in a space defined in the Y-axis direction between pair of guide rails311. Multiple ring-like permanent magnets are disposed on motor shaft321along an axial direction. The multiple permanent magnets are disposed in such a manner that magnetic poles of two adjacent magnets differ from each other.

Motor block322is a movable device that is disposed on motor shaft321so as to slide over motor shaft321in a direction in which motor shaft321extends. Motor block322include multiple inductors that are disposed along the extending direction of motor shaft321. Cooling device323is made up of a heat conductive pipe, a fan, and the like, all of which are not illustrated. Cooling device323dissipates heat generated as a result of driving of linear motor32to an exterior portion to thereby cool linear motor32.

Y-axis moving body313of Y-axis guide device31is fixed to a lower portion of motor block322of linear motor32. Linear motor32generates a thrust by feeding the inductors of motor block322. Linear motor32moves Y-axis moving body313fixed to motor block322to a predetermined position in the Y-axis direction by controlling the feeding of the inductors.

X-axis guide device33moves mounting head35in a left-right direction (an X-axis direction) of base2. X-axis guide device33includes X-axis rail331and X-axis moving body332. X-axis rail331is disposed on Y-axis moving body313in such a manner as to extend in the X-axis direction. X-axis moving body332is in slidable engagement with X-axis rail331. X-axis moving body332is moved to a predetermined position in the X-axis direction by a drive device, not illustrated. To the drive device, for example, a ball screw device or a linear motor can be applied.

Mounting head35is fixed to X-axis moving body332by a clamp, not illustrated. Mounting head35includes multiple suction nozzles36that are provided detachably. Mounting head35supports suction nozzles36individually in such a manner as to be revolved around an R axis parallel to a Z axis and lifted up and down. The lifting and lowering position and angle of each suction nozzle36relative to mounting head35, along with the supply of negative pressure, are controlled. When supplied with negative pressure, each suction nozzle36picks up through suction a component supplied by feeder21of component supply device20.

Two component transfer devices30that are configured in the way described above are disposed to be aligned side by side in the X-axis direction and are allowed to operate independently of each other. Specifically, as illustrated inFIGS. 3 and 4, respective mounting heads35of two component transfer devices30individually mount components on boards Bd in corresponding movable ranges Rm1, Rm2that are defined above base2so as not to overlap each other. Here, movable ranges Rm1, Rm2are ranges determined by a mechanical configuration of Y-axis guide device31and X-axis guide device33and are defined as a range that encircles mounting head35when moving mounting head35to both left and right ends and both front and rear ends.FIGS. 3 and 4illustrate respective movable ranges Rm1, Rm2of two component transfer devices30in the X-axis direction.

Hereinafter, for the sake of simplifying the description, as denoted by parenthesized reference numerals inFIG. 2, of two component transfer devices30, in component transfer device35on a left side (an upstream side in a conveyance direction of board Bd), Y-axis guide device31is also referred to as first guide device40, linear motor32as first drive device45, and mounting head35as first head46. Left rail311L and right rail311R that constitute pair of guide rails311of first guide device40are also referred to as first left rail41and first right rail42, respectively.

Further, of two component transfer devices30, in component transfer device35on a right side (a downstream side in the conveyance direction of board Bd), Y-axis guide device31is also referred to as second guide device50, linear motor32as second drive device55, and mounting head35as second head56. Left rail311L and right rail311R that constitute pair of guide rails311of second guide device50are also referred to as second left rail51and second right rail52, respectively.

1-3. Detailed Configuration of Frame Structure80

In this embodiment, frame structure80is fixed to front column member60and rear column member70, which each have an integral portal-like structure, while spanning these column members. In this embodiment, as illustrated inFIG. 3, frame structure80has a rectangular shape that surrounds an outer circumference of component mounter1when viewed from above. Frame structure80has a box-like shape that is opened downwards and upwards to thereby ensure structural rigidity thereof.

As illustrated inFIG. 3, frame structure80includes left frame81, right frame82, center frame83, front frame84, rear frame85, and the like. Left frame81extends in the front-rear direction (the Y-axis direction) of base2and spans a space defined between a left end portion of front column60and a left end portion of rear column member70. As illustrated inFIG. 4, in left frame81, the external shape of a cross section at right angles to the Y-axis direction extends in an up-down direction. First left rail41of first guide device40is provided at a lower portion of left frame81.

Right frame82is axially symmetric with left frame81with respect to the center of base2in the left-right direction thereof as a center line. As illustrated inFIG. 3, right frame82extends in the front-rear direction (the Y-axis direction) of base2and spans a space defined between a right end portion of front column member60and a right end portion of rear column member70. As illustrated inFIG. 4, in right frame82, the external shape of a cross section at right angles to the Y-axis direction extends in the up-down direction. Second right rail52of second guide device50is provided at a lower portion of right frame82.

As illustrated inFIG. 3, center frame83is disposed between left frame81and right frame82in the X-axis direction. Center frame83extends in the Y-axis direction and spans a space defined between a center portion of front column member60and a center portion of rear column member70. As illustrated inFIG. 4, in center frame83, the external shape of a cross section at right angles to the Y-axis direction has a rectangular shape that extends in the up-down direction. First right rail42of first guide device40and second left rail51of second guide device50are provided at a lower portion of center frame83.

As illustrated inFIG. 3, front frame84and rear frame85extend in the X-axis direction, and in each of front frame84and rear frame85, the external shape of a cross section at right angles to the X-axis direction extends in the up-down direction. Front frame84connects respective upper portions of pair of front columns61together and also connects respective front end portions of left frame81, right frame82, and center frame83together. Rear frame85connects respective upper portions of pair of rear columns71and also connects respective rear ends of left frame81, right frame82, and center frame83together.

Here, in this embodiment, pair of front columns61are connected together by connecting member62to thereby form front column member60, which has an integral portal-like structure. In this embodiment, pair of rear columns71are connected together by connecting member72to thereby form rear column member70, which has an integral portal-like structure. With this configuration, the rigidity of base2in the left-right direction thereof can be further increased. Further, the overall rigidity of component mounter1is increased as a result of connecting front column member60and rear column member70being connected together by frame structure80, thereby making it possible to reduce further a risk of generating vibrations.

In this embodiment, an outer frame of frame structure80connects together left frame81, right frame82, front frame84, and rear frame85each having almost the same width in the up-down direction. In frame structure80, center frame83is disposed between left frame81and right frame82, fabricating a structure that increases the rigidity further. The cross sections of frames81to86are elongated in the up-down direction increasing the modulus of sectional shape, thereby increasing the bending rigidity of frame structure80. As a result, frequencies in the X-axis direction and the Y-axis direction of vibrations generated in association with movement of first head46and second head56can be increased.

In this embodiment, frame structure80ensures the rigidity in the X-axis direction required for frame structure80(for example, the rigidity with which a frequency of vibration in the X-axis direction that is generated by a specified operation of mounting head35reaches a threshold value or greater) with front frame84and rear frame85. As a result, frame structure80includes no other member configured to connect left frame81and right frame82together other than front frame84and rear frame85. As a result, a reduction in weight of frame structure80as well as a reduction in production cost and installation cost of frame structure80is achieved.

As a result of adopting the configuration described above, frame structure80has the box-like shape that is opened in the up-down direction and ensures a space for installing first drive device45between left frame81and center frame83and a space for installing second drive device55between right frame82and center frame83. Specifically, first drive device45is disposed between left frame81and center frame83in the X-axis direction and is supported at both end portions in the front-rear direction of base2by front frame84and rear frame85. Similarly, second drive device55is disposed between right frame82and center frame83in the X-axis direction and is supported at both end portions in the front-rear direction of base2thereof by front frame84and rear frame85.

Specifically, as illustrated inFIG. 3, first drive device45and second drive device55, which are both linear motors32, are supported at both end portions of motor shafts321thereof in the Y-axis direction by front frame84and rear frame85. Then, first drive device45applies a driving force for moving first head46in the front-rear direction of base2to first moving body43. Similarly, second drive device55applies a driving force for moving second head56in the front-rear direction of base2to second moving body53.

As described above, first left rail41of first guide device40is provided at the lower portion of left frame81. In this embodiment, as illustrated inFIG. 4, first left rail41is disposed within a range where movable range Rm1of first head46overlaps support range Rs in the left-right direction of base2where pair of front columns61and pair of rear columns71are connected to frame structure80. InFIG. 4, inner end faces of left front column61and left rear column71are indicated by broken lines.

Second right rail52of second guide device50is provided at the lower portion of right frame82. In this embodiment, as illustrated inFIG. 4, second right rail52is disposed within a range where movable range Rm2of second head56overlaps support range Rs in the left-right direction of base2where pair of front columns61and pair of rear columns71are connected to frame structure80. InFIG. 4, inner end faces of right front column61and right rear column71are indicated by broken lines.

Here, support ranges Rs are ranges in the X-axis direction where frame structure80connects to front column member60and rear column member70. Support ranges Rs correspond to ranges represented by a range in the X-axis direction where left frame81is supported directly or indirectly by one of the pair of front columns61and one of the pair of rear columns71and a range in the X-axis direction where right frame82is supported directly or indirectly by the other of the pair front columns61and the other of the pair of rear columns71.

With such a configuration, a downward load exerted to left frame81from first left rail41is generally transmitted to left front column61and left rear column71that reside in support range Rs as a buckling load. Similarly, a downward load exerted to right frame82from second right rail52is generally transmitted to right front column61and right rear column71that reside in support range Rs as a buckling load.

As a result of the transmission of the loads in this way, first guide device40and second guide device50, which generate vibrations as movement occurs, are supported with the buckling strengths of front column member60and rear column member70via frame structure80. As a result, the overall structural rigidity of component mounter1is increased, thereby not only suppressing the generation of vibrations but also increasing the frequency of generated vibrations.

First right rail42of first guide device40and second left rail51of second guide device50are provided at the lower portion of center frame83. In this embodiment, as illustrated inFIG. 4, first right rail42is disposed inside movable range Rm1of first head46in the X-axis direction. Similarly, second left rail51is disposed inside movable range Rm2of second head56in the X-axis direction.

Here, as illustrated inFIG. 2, pair of front columns61and pair of rear columns71both have side surfaces611,711, on both sides in the left-right direction (the X-axis direction) of base2, constituting the same flat plane. This configuration is designed to enable installation of component mounter1as close to another adjacent component mounter1as possible as illustrated inFIG. 1when a production line including component mounters1is configured. As a result, the production line including component mounters1can be shortened to thereby improve the productivity per unit area in an assembling facility.

Further, as illustrated inFIG. 1, pair of left and right connecting plates89are disposed on side surfaces611of pair of front columns61and side surfaces711of pair of rear columns71to connect side surfaces (611,711) together. As a result of adopting this configuration, component mounter1increases its overall rigidity in the front-rear direction by making use of the tensile strength of connecting plates89. Consequently, this configuration increases particularly the rigidity in the Y-axis direction, increasing the frequency in the Y-axis direction of vibrations generated as first head46and second head56move.

1-4. Advantageous Effects of Configuration of First Embodiment

With the configuration of component mounter1described above, pair of front columns61and pair of rear columns71are connected together by frame structure80. As a result, the overall rigidity of component mounter1is improved by the structural rigidity of frame structure80while maintaining the overall external dimensions of component mounter1. Thus, the frequency of vibrations generated as first head46and second head56move can be increased. As a result of increasing the frequency of the vibrations, suppressing and controlling the vibrations comes to be facilitated, which means an improvement in mounting accuracy is achieved by reducing the effect of the vibrations.

Additionally, in frame structure80, first guide device40and second guide device50, which are suspended, are supported by providing individual rails (41,42,51,52) at the lower portions of left frame81, right frame82, and center frame83. As a result of adopting this configuration, component mounter1reliably bears the loads of first guide device40and second guide device50with base2, front column member60, rear column member70, and frame structure80, making it possible to suppress the occurrence of vibrations that would otherwise be caused as first head46and second head56move.

2. Second Embodiment

2-1. Configuration of Component Mounter101

A work machine (component mounter101) of a second embodiment differs from component mounter1of the first embodiment mainly in the configuration of frame structure80. Since other common configurations are substantially the same as those of the first embodiment, detailed descriptions thereof will be omitted. Specifically, as illustrated inFIG. 5, component mounter101includes base102, board conveyance device10, component supply device20(omitted inFIG. 5), one component transfer device30(first guide device140), front column member160, rear column member170, frame structure180, control device90, and the like.

In contrast to the configuration of component mounter1of the first embodiment in which two component transfer devices30are provided, component mounter101of this embodiment has only one component transfer device30. Due to this, compared with component mounter1of the first embodiment, widths in an X-axis direction of component mounter101and base102are generally half of those of component mounter1. Component transfer device30of this embodiment is of the same type as two component transfer devices30of the first embodiment and includes first guide device140, first drive device145, first head146, and the like.

Front column member160has an integral portal-like structure, which has pair of front columns61, provided at left and right sides of a front portion of base102, connected by connecting member162extending in the X-axis direction. Similarly, rear column member170has an integral portal-like structure, which has pair of rear columns71provided at left and right sides of a rear portion of base102connected by connecting member172extending in the X-axis direction.

2-2. Detailed Configuration of Frame Structure180

Frame structure180is a strength member that supports one component transfer device30and improves the overall rigidity of component mounter101by connecting front column member160and rear column member170together. Frame structure180has a similar configuration to the configuration of frame structure80of the first embodiment except that center frame83is removed from or is not provided on frame structure180and includes left frame81, right frame82, front frame84, rear frame85, and the like.

As illustrated inFIG. 6, first left rail41of first guide device140is provided at a lower portion of left frame81. First right rail42of first guide device140is provided at a lower portion of right frame82. As in the first embodiment, front frame84connects pair of front columns61together and also connects respective front ends of left frame81and right frame82together. Rear frame85connects pair of rear columns71together and also connects respective rear ends of left frame81and right frame82.

As illustrated inFIG. 6, first left rail41and first right rail42of first guide device140are disposed within ranges where movable range Rm1of first head46overlaps support ranges Rs in a left-right direction of base102where pair of first front columns61and pair of rear columns71are connected to frame structure180. InFIG. 6, inner end faces pair of front columns61and pair of rear columns71are indicated by broken lines.

First drive device145is disposed between left frame81and right frame82. As illustrated inFIG. 5, first drive device145is supported at both end portions in the front-rear direction of base102by front frame84and rear frame85. Specifically, first drive device145, which is a linear motor32, is supported at both end portions of motor shaft321in a Y-axis direction by front frame84and rear frame85. First drive device145applies a driving force, to first moving body43, for moving first head146in the front-rear direction of base102.

As a result of adopting this configuration, as in the configuration of the first embodiment, a downward load exerted to frame structure180from first guide device140is generally transmitted to pair of front columns61and pair of rear columns71that both reside in support ranges Rs as a buckling load. As a result, first guide device140, which can generate vibrations as it operates, is supported with the bucking strengths of front column member160and rear column member170via frame structure180. As a result, in component mounter101, not only is the generation of vibrations suppressed by increasing the overall structural rigidity of component mounter101, but also the frequency of generated vibrations is increased.

2-3. Advantageous Effects of Configuration of Second Embodiment

With the configuration of component mounter101described above, pair of front columns61and pair of rear columns71are connected together by frame structure180. As a result, in component mounter101, the overall rigidity thereof is improved by the structural rigidity of frame structure180while maintaining the overall external dimensions of component mounter101. Thus, the frequency of vibrations generated as first head146moves can be increased. As a result, suppression and control of the vibrations are facilitated, thereby reducing the effect of the vibrations and improving working accuracy.

In frame structure180, first guide device140, which is suspended, is supported by providing the individual rails (41,42) at the lower portions of left frame81and right frame82. As a result, in component mounter101, the load of first guide device140can be reliably borne by base102, front column member160, rear column member170, and frame structure180, thereby making it possible to suppress the generation of vibrations that would otherwise be caused as first head146moves.

3. Modified Examples of First and Second Embodiments

3-1. Configuration of Frame Structure80

In the first embodiment and the second embodiment, frame structures80,180have a box-like shape that is opened downwards and upwards. In contrast to the configuration described above, frame structures80,180may have, for example, a shape that is covered with a plate or a cover member at the upper side thereof. Additionally, as long as the overall rigidity of the frame structure can be ensured, the external shape of a cross section of at least part of each frame (81,82,84,85) that constitutes the outer frame of the frame structure may have shapes other than a shape that is elongated in the up-down direction, and hence, the frame structure need not have a box-like shape.

In addition, in the first embodiment and the second embodiment, front column members60,160form an integral portal-like structure as a result of pair of front columns61being connected together by connecting members62,162. In contrast to the configuration described above, front column members60,160need not have connecting members62,162and may be connected together only at upper portions thereof by frame structures80,180. Similarly, rear column members70,170need not have connecting members72,172and may be connected together only at upper portions thereof by frame structures80,180. However, from the viewpoint of securing the rigidity and reducing the number of components, the aspects exemplified in the first embodiment and the second embodiment are desirable.

3-2. Configuration of Connecting Plate89

In the first and second embodiments, pair of connecting plates89are individually made to connect the respective side surfaces (611,711) of pair of front columns61and pair of rear columns71together. In contrast to the configuration described above, in frame structures80,180, side surfaces801on both the sides in the X-axis direction may both constitute the same planar shape as the side surfaces (611,711), and pair of front columns61and pair of rear columns71may be connected together by pair of connecting plates89.

With this configuration, in component mounters1,101, the overall rigidity in the front-rear direction can be increased further by the tensile strength of pair of connecting plates89. As a result, since the frequency of vibrations in the front-rear direction generated as mounting head35moves can be increased, the suppression and control of the vibrations is facilitated, thereby reducing the effect of the vibrations and improving mounting accuracy. Further, connecting plates89may be made to connect the side surfaces of bases2and102.

3-3. Basic Configuration of Work Machine

In the first and second embodiments, first drive devices45,145and second drive device55are each described as being linear motor32. In contrast to the configuration described above, a linear motion device such as a ball screw device may be applied to first drive devices45,145and second drive device55, as long as the linear motion device can apply, to first moving body43and second moving body53, a driving force for moving first heads46,146and second head56in the front-rear direction (the Y-axis direction) of bases2,102. For example, in the case where first drive devices45,145and second drive device55are each made up of a ball screw device, both end portions of a threaded shaft are supported by front frame84and rear frame85.

In the first embodiment and the second embodiment, the work machine is described as forming component mounters1,101for producing board products. In contrast to the configuration described above, the work machine may be of various types of work machines other than the component mounter, as long as such work machines are such that various types of work are performed by moving the head. Specifically, the work machine may be a solder printer that constitutes a production line together with component mounters1,101or an inspection device configured to inspect circuit boards on which components are mounted.

REFERENCE SIGNS LIST