Component mounting apparatus

A component mounting apparatus has an intermittently rotated rotary mounting section which has a driver at an upper part for driving motors of mounting heads arranged on periphery of the rotary mounting section. A controller in a stationary part of the apparatus inputs power and control signals to the rotating driver which is formed in an annular shape, and includes motor driver mounting plates with motor drivers for controlling power supplied to each motor. The motor driver mounting plates are arranged radially around a rotation axis of the rotating driver with planar surfaces in parallel to the rotation axis.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a component mounting apparatus for mounting parts such as electronic components onto a substrate or the like. More particularly, the invention relates to a component mounting apparatus having a rotary mounting section provided with a plurality of mounting heads on the outer periphery thereof.

2. Description of Related Art

A known high-speed component mounting apparatus includes a rotary mounting section1for picking up components from a given component supply source3in a supply section2and for placing the components on a substrate5positioned on an X-Y table4, as shown in FIG.6. The apparatus further has a transfer rail for carrying in and out the substrate5, and a display unit for indicating operating conditions and alarms, should the apparatus malfunctions.

The rotary mounting section1includes, as shown inFIG. 7, a rotary table8having a plurality of mounting heads10on its outer periphery, only one of which is shown in the drawing for ease of illustration, and a rotary drive member9having a rotary shaft8aat its lower face for imparting intermittent motion of the rotary table8at a pitch space corresponding to the distance between two adjacent mounting heads10. Each of the mounting heads10includes a suction nozzle10afor holding a component and a motor11used for switching the suction nozzle from one type to another.

The rotary drive member9is provided with a support plate9athereon which rotates integrally with the rotary shaft8a. At the peripheral edge of the support plate9ais provided a plurality of box-shaped drivers51for respectively driving each of the motors11. A mercury contact type connector52is provided in the center of the support plate9afor inputting drive power and control signals for the motors11to the drivers51from a controller (not shown) built in a stationary part of the apparatus. The drivers51output the drive power and control signals thus inputted thereto via the connector52to the motors11of their respective mounting heads10through a wiring12passing through the hollow interior of the rotary shaft8aand the rotary table8.

Since the circular support plate9aholds the plurality of evenly spaced box-shaped drivers51thereon at its circumference, the space required for allowing the support plate with drivers to freely rotate is reduced as compared to a case where a single such box-shaped driver is held on the support plate. Nevertheless, these drivers51still require a relatively large installation space because of their corners protruding beyond the circumference of the support plate, thereby increasing the radius of rotation of the support plate. This causes bulkiness of the apparatus.

The driver51accommodates various circuit boards or substrates therein, among which the one having a motor driver for controlling electric current applied to the motor11is subjected to a large load and apt to generate heat. It is therefore desirable to cool the substrate, but it is built in a confined space in close proximity to other substrates within a box and effective cooling thereof is hardly achieved. Such substrate is also apt to fail because of the heat, but replacement of the substrate requires considerable work and time in view of the built-in structure, causing the productivity to lower.

SUMMARY OF THE INVENTION

The present invention has been devised in light of the above-described problems encountered by the prior art, and it is an object of the invention to provide a component mounting apparatus with a reduced driver installation space wherein a motor driver, which is apt to generate heat and fail because of large load, to be efficiently cooled and readily replaced.

To achieve the object, a component mounting apparatus according to the present invention includes a rotary table, having a plurality of mounting heads disposed on the periphery thereof and driven to rotate intermittently at a pitch corresponding to a pitch distance between adjacent mounting heads, a driver for driving motors respectively provided in each of the plurality of mounting heads, and a controller placed in a stationary part of the apparatus for inputting power and control signals to the driver. The characteristic feature of the component mounting apparatus is that the driver is formed in an annular shape.

These and other objects and characteristics of the present invention will become further clear from the following description with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows a rotary mounting section1of a component mounting apparatus according to one embodiment of the invention. The mounting head10is held on a rotary table8, with its body13being slidable upwards and downwards along a slide guide14. A groove cam (not shown) is provided to a stationary part around the rotary table8above the body13of the mounting head10, so that the mounting head10is moved upwards and downwards by the engagement between the groove cam and a cam follower (not shown) provided to the body13of the nozzle for picking up and mounting of components with the rotation of the rotary table8. The rotary table8holds a plurality of such mounting heads10equally spaced at the circumference thereof, only one of which is shown in the drawing for ease of illustration. Each of the mounting heads10is rotatable around its axis by their respective motor11.

A rotary drive member9is arranged in an upper part of the rotary mounting section1, having a support plate9a, on which an annular driver15is mounted for driving and controlling the motor11of each mounting head10. The annular driver15rotates in synchronism with the mounting heads10. A connector16is mounted in the hollow part of the annular driver15, to which drive power and control signals for the motors11are input from a controller17(seeFIG. 2) mounted on a stationary part of the apparatus. The connector16is composed of a cylindrical slip ring (not shown) for supplying drive power and an infrared receiver/transmitter18for passing on the control signals (see FIG.2).

Referring toFIG. 2, the controller17includes a main CPU19for controlling the overall operation of the component mounting apparatus, and a communication unit20for sending out and receiving control signals to and from the driver15via the infrared receiver/transmitter18. The driver15includes a communication unit21for sending and receiving the control signals, a sub CPU22for processing the control signals, and a pulse generator23for outputting electric current control signals for each of the motors11, which, in this preferred embodiment, are pulse motors, and a motor driver24for controlling drive power to the motors based on the electric current control signals and for applying controlled electric current to the motors11via a wiring12.

The driver15includes a lower plate25, an upper plate26, a base plate27, and a cover plate28, which are all formed in an annular shape, as shown inFIG. 3to FIG.5. The lower plate25and the upper plate26are spaced apart and connected to each other by four posts29standing at the inner circumference thereof. The base plate27is placed upon protrusions26aon the upper plate26and screwed thereto, while the cover plate28is placed upon the protrusions27aon the base plate27and screwed thereto.

On the base plate27is arranged the above-mentioned communication unit21, the sub CPU22, and the pulse generator23. Between the lower plate25and the upper plate26are a plurality of motor driver mounting plates30arranged radially around the rotation axis of the driver15, with their plane surfaces being perpendicular to the lower plate25, i.e., in parallel to the rotation axis of the rotary table8. The above-mentioned motor drivers24for each of the motors11are attached respectively to each one of the motor driver mounting plates30.

On one side face of the motor driver mounting plate30is formed a plurality of mounting bosses30aas shown inFIG. 5for attaching a PCB substrate including the motor driver24. The top edge and the bottom edge of the motor driver mounting plate30are bent toward one side for forming bonding flanges31,32which respectively make surface contact with the upper surface of the lower plate25and the lower surface of the upper plate26. The bonding flanges31,32have respective V-shaped notches33at the edge on the inner side in the radial direction of the annular upper and lower plates25,26. The motor driver mounting plate30further includes a lower mounting piece34and an upper mounting piece35bent toward the other side at the edge on the outer side in the radial direction of the annular upper and lower plates25,26. The upper and lower mounting pieces34,35respectively have a mounting hole36therein.

The lower plate25has a locator pin37on its upper surface at the inner periphery thereof, while the upper plate26has likewise a locator pin37on its lower surface at the inner periphery thereof. These locator pins37engage with the notches33in the bonding flanges31,32, whereby positioning of the motor driver mounting plate30in the circumferential direction is achieved. The lower plate25further has a lower bracket38provided to the upper surface at the outer peripheral edge thereof, while the upper plate26has an upper bracket39attached to the lower surface at the outer peripheral edge thereof. These brackets38,39respectively have connecting surfaces38a,39awhich are superposed upon the backside of the mounting pieces34,35, respectively, and screw holes40formed therein. The mounting pieces34,35are brought into surface contact with the connecting surfaces38a,39awith their respective holes36,40in registry, and fastened to each other with bolts41.

As described above, the driver15has a circular shape in cross section, thus reducing the radius of rotation as compared to the prior art. As a result, the driver15requires smaller installation space, enabling the apparatus to be made compact.

Thus the plurality of motor driver mounting plates30, to which are attached PCB substrates including the motor drivers24for controlling power supply to the motors11, stand in parallel to the rotation axis of the driver15, i.e., perpendicularly to the annular upper and lower plates25,26in a radially distanced arrangement. Accordingly, the motor drivers24which apt to generate heat are effectively cooled by air, as a cooling medium, flowing through the space between adjacent motor driver mounting plates30.

The motor drivers24are apt to fail because of heat as mentioned above. Even in the event of failure in some of the motor drivers24, the invention enables such malfunctioning motor drivers to be readily replaced in view of the motor driver mounting plates30that are detachable in a radial direction. Each of the motor driver mounting plates30is fixed in position, with its notch33at the inner peripheral side edge being engaged with the locator pins37of the upper and lower plates25,26, and its mounting pieces34,35at the outer peripheral side edge being fastened to the brackets38,39of the upper and lower plates25,26with the bolts41. Therefore, it is removable in a radial direction as indicated by a white arrow inFIG. 5, and thus mounting and dismounting of the motor driver mounting plate30are readily achieved by fastening the bolts41or removing same. Even though the driver15is disposed in a position relatively high above the rotary mounting section1, the motor driver mounting plates30are readily replaceable due to such structure.

Moreover, the driver15of the present invention allows for easy modification in respect of the number of mounting heads11to be mounted, i.e., by varying the position and the number of the upper and lower brackets38,39of the upper and lower plates25,26, respectively, the number of motor driver mounting plates30can be changed as required.

In the preferred embodiment, the controller17stops the operation of the component mounting apparatus upon detecting a malfunction in any of the motor drivers24, and makes an indication on a display7or the like for reporting such failure. Furthermore, the controller17drives the intermittent rotary driver member9so as to cause the motor driver mounting plate30to which the malfunctioning motor driver24is attached to come to a predetermined position where maintenance is performed. In this way, replacement of a motor driver mounting plate30is swiftly effected at a predetermined position in the event of a malfunction of a motor driver, thus improving working efficiency.

The subject matter of the invention is not limited to the above-described specific example and various modifications may be made. For example, the motor11may be servo-motors such as AC motors or voice coil motors instead of pulse motors. Also, any suitable structure may be adopted for the connector16which, in the above-described embodiment is constructed of a slip ring and an infrared receiver/transmitter.

The motor driver mounting plates30should not necessarily be arranged radially as in the above-described embodiment. For example, a suitable number of motor driver members may be arranged perpendicularly in parallel to each other with spaces therebetween, and these groups of motor driver mounting plates may be arranged radially along the circumference of the driver15. Alternatively, a plurality of motor driver members may be stacked parallel to each other with spaces therebetween in a vertical direction, these groups of motor driver members being radially arranged along the circumference of the driver15.

As described above, according to the component mounting apparatus of the invention, the rotary driver requires smaller space for installation, enabling the apparatus to be made compact. Motor driver mounting plates, to which motor drivers for controlling motors are attached, are spaced apart from each other, thus achieving high cooling performance and allowing easy access for maintenance.

Although the present invention has been fully described in connection with the preferred embodiment thereof, it is to be noted that various changes and modifications apparent to those skilled in the art are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.