CAN MAKING MACHINE

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from Japanese Patent Application No. 2016-154845 filed on Aug. 5, 2016, the entire contents of which are incorporated herein by reference.

BACKGROUND
Field of the Invention

The present invention relates to a can making machine which processes a cylindrical body (workpiece) to make a bottle can or an aerosol can.

Description of Related Art

Conventionally, as a can making machine which makes a bottle can, an aerosol can or the like made of an aluminum alloy material or the like, for example, an apparatus disclosed in Japanese Unexamined Patent Application, First Publication No. 2005-329424 is known.

A can making machine includes a main body frame, a holding table which is supported by the main body frame to hold a cylindrical body (workpiece), and a processing table which is supported by the main body frame via a shaft section penetrating the holding table in a direction of the table axis and disposed to face the holding table in the direction of the table axis and on which a processing tool for processing the cylindrical body is provided. The holding table is generally called a turntable or an index table, and the processing table is generally called a die table. These tables have a disk shape or a circular ring shape, their central axes (table axes) extend in a horizontal direction, and the central axes of the respective tables are disposed coaxially with each other.

In the holding table, cylindrical bodies such as DI cans are held as a workpiece along a circumferential direction of the table about the table axis. Specifically, chucks (cylindrical body holding tools) capable of holding the cylindrical bodies arranged in the circumferential direction of the table are provided on the holding table, and the cylindrical bodies are held on the chucks in a posture in which opening ends thereof are directed toward the processing table. In the processing table, processing tools for processing the cylindrical bodies are arranged along the circumferential direction of the table. Specifically, mounting holes penetrating in the direction of the table axis are formed in the processing table to be arranged in the circumferential direction of the table, and the processing tools are attached to the mounting holes in the processing order to the cylindrical bodies.

The processing tools include a die processing tool and a rotary processing tool. The die processing tool moves in the direction of its central axis (direction parallel to the table axis) with respect to the cylindrical body, and performs die processing such as drawing for reducing a diameter of a peripheral wall of the cylindrical body, or diameter expansion processing for expanding the diameter of the peripheral wall. The rotary processing tool moves around the central axis with respect to the cylindrical body to perform rotary processing such as trimming, screw forming, curling and throttle (curl crimping) processing on the peripheral wall of the cylindrical body by the rotary operation about the central axis.

Further, a crank unit, a table index unit and a wheel index unit are provided on the main body frame of the can making machine. The holding table and the processing table repeat an approaching movement and a separating movement in the direction of the table axis by the crank unit, and are intermittently relatively rotated in the circumferential direction of the table by the table index unit. Specifically, the processing table moves toward or away from the holding table in the direction of the table axis, and during one stroke (reciprocating movement) between the approaching movement and the separating movement, the holding table is rotationally moved relative to the processing table in the circumferential direction of the table by a predetermined amount.

Further, for each stroke in which the tables move toward or away from each other, the cylindrical body (workpiece) is processed, and the cylindrical body is moved to a processing position of the next processing tool. By repeating this operation, the cylindrical body held by the holding table is sequentially processed by processing tools provided on the processing table, and when the series of processing is finished, a can having a desired shape (a bottle can, an aerosol can, etc.) is made.

Further, a supply wheel (infeed wheel) which supplies the cylindrical body to the holding table, and a discharge wheel which discharges the cylindrical body (can) after processing from the holding table are provided in the can making machine. The supply wheel and the discharge wheel are supported by the main body frame and each central axis (wheel axis) is disposed parallel to the table shaft. On the respective outer peripheral surfaces of the supply wheel and the discharge wheel, recesses capable of holding the peripheral wall of the cylindrical body are formed at intervals in the circumferential direction. The supply wheel and the discharge wheel are intermittently rotated about each wheel axis in synchronism with the intermittent rotation about the table axis of the holding table by the wheel index unit and in a rotary direction opposite to the rotary direction of the holding table.

Further, when the supply wheel rotates intermittently and the cylindrical body held in the recess of the supply wheel is disposed at a position (just above the chuck) corresponding to the chuck of the holding table, a push-in portion provided in the processing table pushes the cylindrical body toward the holding table side, and the cylindrical body is delivered from the recess to the chuck and held by the chuck. Further, when the cylindrical body held by the chuck of the holding table is disposed at a position (just below the recess) corresponding to the recess of the discharge wheel after the overall processing is finished, a piston unit provided on the holding table pushes the cylindrical body toward the discharge wheel side, and the cylindrical body is delivered from the chuck to the recess and is held in the recess.

However, in the conventional can making machine, it was difficult to change an effective stroke of the processing table, and it was possible to make only cans of a constant drawing depth (processing height). That is, it was not possible to flexibly respond to a demand for increasing the processing height, such as performing the drawing process deeper than the conventional can. The effective stroke refers to a length in the direction of the table axis (the central axis direction of the cylindrical body) capable of processing the cylindrical body, during one stroke (among the total length of the stroke) in which the processing table approaches and moves away from the holding table in the direction of the table axis.

The aforementioned problem will be described in detail. In a conventional can making machine 100 shown in FIG. 7, a crank unit 101, a table index unit 102, and a wheel index unit 103 are driven by a single drive motor 104. That is, the crank unit 101, the table index unit 102, and the wheel index unit 103 are mechanically connected by gears, pulleys, belts, and the like, and are driven by the drive motor 104 in conjunction with each other.

The crank unit 101 includes a drive shaft 105, a crank shaft 106 which rotates about the central axis O of the drive shaft 105, a connecting rod (not shown in FIG. 7) which connects the crank shaft 106 and a shaft section connected to the processing table. In FIG. 7, reference numeral 107 denotes a holding table which is intermittently rotated about a table axis TA by the table index unit 102, and reference numeral 108 denotes a reduction gear pair which is directly connected to the drive shaft 105. Also, reference numeral 109 denotes a supply wheel, and reference numeral 110 denotes a discharge wheel. By the wheel index unit 103, the supply wheel 109 is intermittently rotated about the wheel axis SA, and the discharge wheel 110 is intermittently rotated about the wheel axis DA.

The table index unit 102 and the wheel index unit 103 both have a cam structure (not shown). The table index unit 102 rotates the holding table 107 about the table axis TA and stops rotation of the holding table 107 (intermittently rotates the holding table 107) with every stroke of the reciprocating movement of the processing table, by the cam structure. Further, the wheel index unit 103 rotates the supply wheel 109 about the wheel axis SA and stops rotation of the supply wheel 109 (intermittently rotates the supply wheel 109) with every stroke of reciprocating movement of the processing table by the cam structure, and rotates the discharge wheel 110 about the wheel axis DA and stops rotation of the discharge wheel 110 (intermittently rotates the discharge wheel 110).

Further, FIG. 4 is a graph showing a relationship between a circumferential position (crank angle) of the crank shaft 106 with respect to the central axis O of the drive shaft 105 and an amount of processing table displacement. The crank angle represents an angular position with respect to the central axis O while the crank shaft 106 makes one revolution (360° rotation) about the central axis O of the drive shaft 105, and the amount of processing table displacement represents an amount of displacement (distance) of processing table from the holding table 107 in the direction of the table axis TA, with a position (a bottom dead center) at which the table is closest to the holding table 107 as a reference (zero). Further, a position at which the processing table is farthest from the holding table 107 is a top dead center.

A dwell period shown in the graph of FIG. 4 means an angle range within which the holding table 107 does not rotate about the table axis TA with respect to the processing table by the table index unit 102 (an angle range of the crank angle within which the rotation of the holding table 107 is stopped). In the range of the dwell period, the processing table moves to approach the holding table 107 in the direction of the table axis TA, and various types of processing are performed on the cylindrical body (workpiece). Further, the range other than the dwell period among all crank angles is referred to as an assignment angle (index angle). Within this range of the assignment angle, the table index unit 102 causes the holding table 107 to rotationally move with respect to the processing table about the table axis TA. That is, the magnitude of the index period is 360°−(magnitude of the dwell period).

Further, in the conventional can making machine 100, in order to synchronize the crank unit 101, the table index unit 102 and the wheel index unit 103 (in order to synchronize the mechanisms), it is not possible to change the ratio (each angle range) of the dwell period and the assignment angle. That is, as shown in the comparative example of the related art in the graph of FIG. 4, the range of the dwell period (75 to 285°) is fixed, and the effective stroke (about 130 mm) determined depending on the range of the dwell period is also fixed and cannot be changed.

In the related art, in order to change (increase) the effective stroke, for example, it is possible to use a so-called variable stroke mechanism (stroke adjusting mechanism) capable of mechanically adjusting the stroke of the reciprocating movement of the processing table in the direction of the table axis with respect to the holding table. However, in this case, not only does the structure of the apparatus become complicated, but the crank radius also changes after the stroke adjustment, and the top dead center and the bottom dead center of the processing table change accordingly. Accordingly, the adjustment workpiece is also cumbersome.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a can making machine capable of changing an effective stroke with a simple structure and capable of making cans of various processing heights without changing the top dead center and the bottom dead center of the processing table.

SUMMARY OF THE INVENTION

A can making machine according to an aspect of the present invention includes a main body frame; a holding table supported by the main body frame to hold a cylindrical body; a processing table which is supported on the main body frame via a shaft section penetrating through the holding table in a direction of a table axis and disposed to face the holding table in the direction of the table axis, and in which a processing tool configured to process the cylindrical body is provided; a crank unit configured to cause the processing table to reciprocate with respect to the holding table in the direction of the table axis; a table index unit configured to intermittently rotationally move the holding table about the table axis with respect to the processing table; a first drive motor configured to drive the crank unit; and a second drive motor configured to drive the table index unit.

In the can making machine of the present invention, the crank unit configured to cause the processing table to reciprocate with respect to the holding table in the direction of the table axis is driven by the first drive motor. Further, the table index unit configured to intermittently rotationally move the holding table with respect to the processing table about the table axis is driven by the second drive motor. That is, the first drive motor configured to drive the crank unit and the second drive motor configured to drive the table index unit are provided separately (independently of each other). Therefore, since it is unnecessary to mechanically connect the crank unit and the table index unit unlike the related art, the following excellent operational effects are obtained.

That is, according to the present invention, while maintaining the constant speed at which the crank unit is driven by the first drive motor (the angular speed at which the crank shaft is rotated about the drive shaft), it is possible to increase the speed (the angular velocity at which the holding table is rotated about the table axis) at which the table index unit is driven by the second drive motor. That is, it is possible to shorten the time required for rotationally moving the holding table in the circumferential direction of the table by a predetermined amount during one stroke in which the processing table reciprocates in the direction of the table axis. Accordingly, it is possible to reduce the angle range (i.e., the magnitude of the index period) of the index period (index angle) in the crank angle. Further, it is possible to increase the angle range of the dwell period (i.e., the magnitude of the dwell period) of the crank angle accordingly.

Specifically, as shown in the graph of FIG. 4 as first to seventh examples of the present embodiment, a larger angle range of the dwell period of the crank angle (horizontal axis) can be secured than in the conventional comparative example. Further, by adjusting the rotational speed of the motor or the like of the second drive motor, the magnitude of the dwell period can be variously set. This makes it possible to increase and variously set the effective stroke. That is, according to the present invention, the effective stroke can be variously changed, without changing the top dead center and the bottom dead center of the processing table (that is, without changing the total length of the stroke). Further, it is possible to flexibly respond to the demand for increasing the processing height, such as performing the drawing process deeper than a conventional can, without requiring a large change in structure in the existing can making machine.

As described above, according to the present invention, the effective stroke can be changed with a simple structure, and cans of various processing heights can be made without changing the top dead center and the bottom dead center of the processing table.

Further, in the can making machine, the crank unit preferably includes a drive shaft; a crank shaft connected to the drive shaft and rotated about a central axis of the drive shaft with rotation of the drive shaft; and a connecting rod configured to connect the crank shaft and the shaft section. The can making machine further includes detecting unit capable of detecting a crank angle which is at a position in a circumferential direction of the crank shaft along a central axis of the drive shaft; and a control unit which controls a rotational speed of the second drive motor based on the crank angle detected by the detecting unit. Further, when the crank angle detected by the detecting unit is in a range of an index period including a top dead center which is at a position at which the processing table is farthest from the holding table, the control unit preferably enhances the rotational speed of the second drive motor as compared with a case in which the crank angle is in a range of a dwell period outside of the range of the index period in the crank angle.

In this case, when the crank angle detected by the detecting unit is in the range of the index period, the rotational speed of the second drive motor can be enhanced by the control unit as compared with the case in which the crank angle is the range of the dwell period. That is, the table index unit rotates the holding table about the table axis at a high speed when the crank angle is in the range of the index period. Therefore, the angle range of the index period of the crank angle can be reliably minimized. A large angle range of the dwell period can be secured, and the effective stroke can be enhanced accordingly.

Further, in the can making machine, it is preferable that the detecting unit be an angular position detecting sensor.

In this case, since the detecting unit is an angular position detection sensor (rotational angle sensor) such as a rotary encoder or a resolver, it is easy to incorporate the detecting unit with a highly precise and compact configuration into the apparatus, and it is easy to obtain and has good handleability.

Further, in the can making machine, it is preferable that the second drive motor be a servomotor.

In this case, since the second drive motor is a servomotor, it is possible to change the rotational speed of the motor, and it is possible to obtain the above-described operation and effect of the present invention with the simple structure.

Further, the aforementioned can making machine further includes a supply wheel configured to supply the cylindrical body to the holding table; a discharge wheel configured to discharge the cylindrical body from the holding table; and a wheel index unit configured to intermittently rotate the supply wheel and the discharge wheel about each wheel axis in synchronization with intermittent rotation about the table axis of the holding table, and the wheel index unit is preferably driven by the second drive motor.

In this case, the table index unit and the wheel index unit can be driven by the same drive motor (second drive motor). Therefore, by mechanically connecting the table index unit and the wheel index unit to each other, it is possible to synchronously and intermittently rotate the holding table, the supply wheel and the discharge wheel reliably and simply.

Further, the above can making machine further includes a supply wheel configured to supply the cylindrical body to the holding table; a discharge wheel configured to discharge the cylindrical body from the holding table; and a wheel index unit configured to intermittently rotate the supply wheel and the discharge wheel about each wheel axis in synchronization with intermittent rotation about the table axis of the holding table, and the wheel index unit is preferably driven by a third drive motor.

In this case, the table index unit is driven by the second drive motor, and the wheel index unit is driven by the third drive motor. Therefore, it is possible to compactly suppress the performance and the external shape of each of the second drive motor and the third drive motor, the range of component selection is expanded and it is easy to fit the components in the apparatus. Also, since the table index unit and the wheel index unit do not need to be mechanically connected to each other, the structure of the apparatus is simplified.

According to the can making machine of the present invention, it is possible to change the effective stroke with a simple structure and to make cans of various processing heights without changing the top dead center and the bottom dead center of the processing table.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing a schematic configuration of a can making machine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along a line II-II of FIG. 1.

FIG. 3 is a diagram for explaining an effective stroke and a crank angle (a dwell period and an index period) of a processing table.

FIG. 4 is a graph showing a relationship between a crank angle and an amount of processing table displacement.

FIG. 5 is a diagram showing a crank unit, a table index unit, a wheel index unit, a first drive motor, a second drive motor, and the like of the can making machine according to an embodiment of the present invention.

FIG. 6 is a diagram showing a crank unit, a table index unit, a wheel index unit, a first drive motor, a second drive motor, a third drive motor, and the like in a modified example of the can making machine according to an embodiment of the present invention.

FIG. 7 is a diagram showing a crank unit, a table index unit, a wheel index unit, a drive motor, and the like of a conventional can making machine.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a can making machine 1 according to an embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, a can making machine 1 of the present embodiment is a so-called bottle necker which makes a bottle can (can) B of a desired shape, by performing various types of bottlenecking including die processing and rotary processing on a cylindrical body W having a bottomed cylindrical shape.

A cylindrical body W supplied as a workpiece to the can making machine 1 is a DI can subjected to drawing & ironing (DI) processing, printing and coating in a previous process. The DI can is formed in a bottomed cylindrical shape, by applying a cupping process (drawing process), a DI process (drawing and ironing process), a trimming process, a printing process, a coating process and the like to a disk-like blank punched out from a plate material such as an aluminum alloy material.

The cylindrical body W includes a cylindrical peripheral wall (can barrel), and a substantially disk-like bottom wall (can bottom). The central axis of the peripheral wall of the cylindrical body W and the central axis of the bottom wall are arranged coaxially with each other, and in the present embodiment, the common axes are referred to as a central axis (can axis) of the cylindrical body W. By subjecting the cylindrical body W to the bottlenecking, a tapered neck portion which gradually decreases in diameter from the barrel portion toward a mouth portion along the direction of the central axis of the cylindrical body W is formed, between the barrel portion (a maximum diameter portion) and the mouth portion (an opening end portion, and a minimum diameter portion) in the peripheral wall. In FIG. 2, the bottle can B made by processing the cylindrical body W using the can making machine 1 is filled with contents such as a beverage in a subsequent process, and the cap is screwed on.

As shown in FIGS. 1 and 2, the can making machine 1 includes a main body frame 4, a holding table 3 which is supported by the main body frame 4 and on which a chuck (cylindrical body holding tool) 7 for holding the cylindrical body W is provided, and a processing table 2 which is supported by the main body frame 4 via a shaft section 5 penetrating through the holding table 3 in a direction of a table axis TA and disposed to face the holding table 3 in the direction of the table axis TA, and on which a processing tool 6 which processes the cylindrical body W is provided. The central axes (table axis TA) of each of the processing table 2 and the holding table 3 extend in the horizontal direction, and these central axes are disposed coaxially with each other.

Further, as shown in FIGS. 1, 3 and 5, the can making machine 1 includes a crank unit 8 which causes the processing table 2 to reciprocate in the direction of table axis TA with respect to the holding table 3, a table index unit 9 which intermittently rotationally moves the holding table 3 with respect to the processing table 2 about the table axis TA, a first drive motor 11 which drives the crank unit 8, and a second drive motor 12 which drives the table index unit 9.

As shown in FIGS. 2 and 5, the can making machine 1 includes a supply wheel 10 which supplies the cylindrical body W to the holding table 3, a discharge wheel 14 which discharges the cylindrical body W (bottle can B) after processing from the holding table 3, and a wheel index unit 15 which intermittently rotates the supply wheel 10 and the discharge wheel 14 about the respective wheel axes SA and DA in synchronism with the intermittent rotation about the table axis TA of the holding table 3. In the present embodiment, the wheel index unit 15 is driven by the second drive motor 12.

In the present embodiment, the direction along the table axis TA (a direction in which the table axis TA extends) is referred to as a direction of the table axis TA. Also, the direction orthogonal to the table axis TA is referred to as the radial direction of the table. In the radial direction of the table, a direction away from the table axis TA is referred to as an outside in the radial direction of the table, and a direction approaching the table axis TA is referred to as an inside in the radial direction of the table. Further, the direction revolving around the table axis TA is referred to as the circumferential direction of the table. In the circumferential direction of the table, a direction in which the holding table 3 is intermittently rotated with respect to the processing table 2 is referred to as a holding table rotary direction R1, and a rotary direction opposite to the rotary direction is referred to as a direction opposite to the holding table rotary direction R1.

Further, the holding table rotary direction R1 is the same direction as the direction in which processing tools 6 to be described later in the processing table 2 are arranged in the circumferential direction of the table in the processing order of to the cylindrical body W. Therefore, the holding table rotary direction R1 can be referred to as downstream in the processing order to the cylindrical body W (a processing forward direction), and the direction opposite to the holding table rotary direction R1 can be referred to as upstream in the processing order to the cylindrical body W.

In FIGS. 1 to 3 and 5, the holding table 3 and the processing table 2 repeat the mutual approaching movement and separating movement in the direction of the table axis TA by the crank unit 8, and are intermittently relatively rotated in the circumferential direction of the table by the table index unit 9. Specifically, the processing table 2 is moved toward or away from the holding table 3 in the direction of the table axis TA, and during one stroke (reciprocating movement) of the approaching movement and the separating movement, the holding table 3 rotationally moves (intermittently rotates) with respect to the processing table 2 in the circumferential direction of the table by a predetermined amount.

Further, for each stroke in which the processing table 2 and the holding table 3 move toward or away from each other, the cylindrical body W held by the chuck 7 of the holding table 3 is processed by the processing tool 6 provided on the processing table 2, and the holding table 3 moves the cylindrical body W downstream (in the holding table rotary direction R1) in the processing order to the processing position of the next (separate) processing tool 6. By repeating this operation, when the cylindrical body W held by the holding table 3 is sequentially processed by processing tools 6 provided on the processing table 2 and the series of processing is finished, a bottle can B having a desired shape is made (see FIG. 2).

The holding table 3 is generally called a turntable or an index table. The holding table 3 has a disc shape or a circular ring shape. Chucks 7 are arranged in the circumferential direction of the table at the outer peripheral portion of the surface of the holding table 3 facing the processing table 2 side. Each of the chucks 7 holds the cylindrical body W, and the opening end portion of the held cylindrical body W is opened toward the processing table 2.

The processing table 2 is generally called a die table. The processing table 2 has a disc shape or a circular ring shape. In the processing table 2, processing tools 6 which process the cylindrical body W held by the holding table 3 are disposed in the circumferential direction of the table. These processing tools 6 are arranged in the circumferential direction of the table on the outer peripheral portion of the surface of the processing table 2 facing the holding table 3 side, and are disposed to face the cylindrical bodies W held by the holding table 3 in the direction of the table axis TA. Further, a processing tool axis (central axis) of the processing tool 6 of the processing table 2, and the central axis (that is, the central axis of the chuck 7) of the cylindrical body W facing the processing tool 6 in the holding table 3 are disposed coaxially with each other. In a state in which the central axis of the cylindrical body W and the processing tool axis coincide with each other, the cylindrical body W is processed by the processing tool 6.

In the processing table 2, mounting holes penetrating in the direction of the table axis TA are arranged and formed in the circumferential direction of the table. The processing tools 6 are attached to the mounting holes in the processing order to the cylindrical body W.

The processing tools 6 include a die processing tool and a rotary processing tool. In the present embodiment, die processing tools and rotary processing tools are detachably disposed in mounting holes of the processing table 2 in the processing order to the cylindrical body W. Some of the mounting holes may be empty spaces to which the processing tool 6 is not attached. Also, oiling tools are disposed in some of the mounting holes.

The die processing tool moves in the direction of its central axis (the direction parallel to the table axis TA) with respect to the cylindrical body W, and performs the die processing such as drawing processing for reducing the diameter of the peripheral wall (can barrel) of the cylindrical body W or diameter expansion processing for expanding the diameter of the peripheral wall. One type of die processing is performed on the cylindrical body W by one die processing tool.

The rotary processing tool moves about the central axis with respect to the cylindrical body W and performs the rotary processing such as trimming, screw forming, curling, and throttle (curl caulking) processing on the peripheral wall (can barrel) of the cylindrical body W by the rotational operation about the central axis. One type of rotary processing is performed on the cylindrical body W by one rotary processing tool.

The shaft section 5 is integrally provided on the processing table 2, extends on the table shaft TA, penetrates through the holding table 3 in the direction of the table axis TA, and is movable with respect to the holding table 3 in the direction of table axis TA. The shaft section 5 is slidably supported by the main body frame 4 in the direction of the table axis TA, and the end portion on the side opposite to the processing table 2 in the direction of the table axis TA is connected to the connecting rod 18 to be described later of the crank unit 8.

The supply wheel 10 is referred to as an infeed wheel and has a substantially cylindrical shape. The supply wheel 10 receives the cylindrical body W supplied from the outside (previous process) of the can making machine 1, and delivers the cylindrical body W to the holding table 3. The discharge wheel 14 is referred to as a discharge wheel and has a substantially cylindrical shape. The discharge wheel 14 receives the cylindrical body W (bottle can B) processed by the can making machine 1 from the holding table 3, and discharges the cylindrical body W to the outside (subsequent process) of the can making machine 1.

The supply wheel 10 is supported by the main body frame 4 and its central axis (wheel axis) SA is disposed parallel to the table axis TA. The supply wheel 10 is rotated about the wheel axis SA in the wheel rotary direction R2. The discharge wheel 14 is supported by the main body frame 4 and its central axis (wheel axis) DA is disposed parallel to the table axis TA. The discharge wheel 14 is rotated about the wheel axis DA in the wheel rotary direction R3.

Recesses (not shown) capable of holding the peripheral wall of the cylindrical body W are formed on the respective outer circumferential surfaces of the supply wheel 10 and the discharge wheel 14 at intervals in the circumferential direction. The supply wheel 10 and the discharge wheel 14 are synchronized with the intermittent rotation about the table axis TA of the holding table 3 by the wheel index unit 15, and are intermittently rotated in the wheel rotary directions R2 and R3 opposite to the rotary direction R1 of the holding table 3. As shown in FIG. 5, the supply wheel 10 and the discharge wheel 14 are mechanically connected by a gear or the like, and intermittently rotate about the respective wheel axes SA and DA in synchronization with each other.

Specifically, in FIG. 2, when the supply wheel 10 intermittently rotates and the cylindrical body W held in the recess of the supply wheel 10 is disposed at a position (just above the chuck 7) corresponding to the chuck 7 of the holding table 3, a pushing portion provided in the processing table 2 pushes the cylindrical body W toward the holding table 3 side, and the cylindrical body W is delivered from the recess to the chuck 7 and is held on the chuck 7. When the cylindrical body W held by the chuck 7 of the holding table 3 is transported in the holding table rotary direction R1 with every stroke of the processing table 2 and is disposed at a position (just below the recess) corresponding to the recess of the discharge wheel 14 after finishing the overall processing, the piston unit provided on the holding table 3 pushes the cylindrical body W (bottle can B) out toward the discharge wheel 14 side, and the cylindrical body W is delivered from the chuck 7 to the recess and is held in the recess. The bottle can B held in the recess is delivered around the wheel axis DA with the intermittent rotation of the discharge wheel 14. After the bottle can B is released from the recess, and then the bottle can B is delivered to the outside of the can making machine 1.

As shown in FIG. 5, the crank unit 8, the table index unit 9, the wheel index unit 15, the first drive motor 11 and the second drive motor 12 are provided on the main body frame 4. In the example of the present embodiment, the first drive motor 11 is an inverter motor, and the second drive motor 12 is a servomotor. The second drive motor 12 is preferably an AC servomotor.

Further, a detecting unit 19 capable of detecting a crank angle to be described later, and a control unit 20 for controlling the rotational speed of the second drive motor 12 on the basis of the crank angle detected by the detecting unit 19 are provided on the main body frame 4. In FIG. 5, reference numeral 21 denotes a clutch & brake to which the rotational driving force of the first drive motor 11 is transmitted via a belt, and reference numeral 22 denotes a reduction gear which reduces the rotational speed from the clutch & brake 21, increases the rotational force (torque), and transmits the rotational force to the drive shaft 16 of the crank unit 8.

In FIG. 3 and FIG. 5, the crank unit 8 has a drive shaft 16, a crank shaft 17 which is connected to the drive shaft 16 and rotated about the central axis O of the drive shaft 16 with the rotation of the drive shaft 16, and a connecting rod 18 which connects the shaft 17 and the shaft section 5. The crank shaft 17 rotates about the central axis O of the drive shaft 16 at a constant angular velocity. The crank unit 8 converts the rotational motion about the central axis O input to the drive shaft 16 into a linear motion in the direction of the table axis TA and outputs the linear motion to the shaft section 5.

The table index unit 9 and the wheel index unit 15 both have a cam structure (not shown). The table index unit 9 rotates the holding table 3 about the table axis TA and stops rotation of the holding table 3 (intermittently rotates the holding table 3) with every stroke of the reciprocating movement of the processing table 2 by the cam structure. Further, the wheel index unit 15 rotates the supply wheel 10 about the wheel axis SA and stops rotation of the supply wheel 10 (intermittently rotates the supply wheel 10) with every stroke of reciprocating movement of the processing table 2 by the cam structure, and rotates the discharge wheel 14 about the wheel axis DA and stops rotation of the discharge wheel 14 (intermittently rotates the discharge wheel 14).

The detecting unit 19 detects the crank angle which is the circumferential position of the crank shaft 17 with respect to the central axis O of the drive shaft 16. The crank angle represents an angular position of the crank shaft 17 with respect to the central axis O while the crank shaft 17 makes one rotation (360° rotation) about the central axis O of the drive shaft 16. In the example of the present embodiment, the detecting unit 19 is an angular position detection sensor (rotational angle sensor) such as a rotary encoder or a resolver.

The crank angle will be described in detail. In (A) and (B) of FIG. 3, when the crank angle is 0°, the processing table 2 is located at the top dead center which is farthest from the holding table 3 in the direction of the table axis TA. Further, as shown in (B) of FIG. 3, when the crank angle is 180°, the processing table 2 is located at the bottom dead center which is closest to the holding table 3 in the direction of the table axis TA.

A range of the dwell period DP and a range of the index period IP are included in all crank angles (0 to 360°) with respect to the central axis O of the drive shaft 16. The range of the dwell period DP is larger than the range of the index period IP, and the sum of the magnitude of the central angle in the range of the dwell period DP and the magnitude of the central angle in the range of the index period IP is 360°. In other words, the magnitude of the index period IP is 360°−(magnitude of the dwell period DP).

In (A) and (B) of FIG. 3 and FIG. 4, the dwell period DP is an angle range in which the holding table 3 is not rotated about the table axis TA with respect to the processing table 2 by the table index unit 9 (the angle range of the crank angle in which the rotation of the holding table 3 is stopped). The dwell period DP includes a bottom dead center (crank angle of 180°). In the range of the dwell period DP, the processing table 2 moves to approach the holding table 3 in the direction of the table axis TA, and various types of processing are performed on the cylindrical body W serving as a workpiece.

Further, the index period (index angle) IP is an angle range in which the holding table 3 rotates about the table axis TA with respect to the processing table 2 by the table index unit 9. The index period IP includes a top dead center (crank angle of 0°). In the range of the index period IP, the processing table 2 is sufficiently spaced apart from the holding table 3 in the direction of the table axis TA, and the cylindrical body W is transported in the table rotary direction R1 to a position facing the processing tool 6 that will perform the next processing.

Further, the total length of the stroke of the reciprocating movement of the processing table 2 in the direction of the table axis TA is obtained by a difference in the distance between the top dead center and the bottom dead center in the direction of the table axis TA. In (A) and (B) of FIG. 3, reference numeral r denotes a crank radius (amount of crank shaft eccentricity), and the crank radius is half (½) of the total stroke length. In the example of the present embodiment, as shown in a vertical axis of the graph of FIG. 4, the total stroke length (the maximum value of the amount of processing table displacement) of the processing table 2 is 220 mm, and the crank radius is 110 mm.

Further, the amount of processing table displacement shown in FIG. 4 represents an amount of displacement (distance) of the processing table 2 from the holding table 3 in the direction of the table axis TA, with a position (bottom dead center) at which the processing table 2 is closest to the holding table 3 as a reference (zero). Further, the effective stroke shown in FIG. 4 refers to a length in the direction of the table axis TA (the direction of the central axis of the cylindrical body W) in which the cylindrical body W can be processed, during one stroke (in the total stroke length) in which the processing table 2 approaches and moves away from the holding table 3 in the direction of the table axis TA.

Specifically, the effective stroke is obtained by a difference in distance between a position of the processing table 2 in the direction of the table axis TA when the crankshaft 17 is disposed at a boundary (a starting point of the range of the dwell period DP) between the index period IP and the dwell period DP as shown in (A) of FIG. 3, and a position of the processing table 2 in the direction of the table axis TA when the crank shaft 17 is disposed at the bottom dead center (crank angle of 180°) as shown in (B) of FIG. 3. Therefore, the effective stroke decreases with respect to the total stroke length of the processing table 2.

Further, when the crank angle detected by the detecting unit 19 is in the range of the index period IP, the control unit 20 increases the rotational speed of the second drive motor 12 as compared with a case of the range of the dwell period DP outside of the range of the index period IP in the crank angle.

Specifically, when the crank angle detected by the detecting unit 19 is in the range of the dwell period DP, the control unit 20 drives the second drive motor 12 at the rotational speed of the motor A (first rotational speed of the motor). Further, when the crank angle detected by the detecting unit 19 is in the range of the index period IP, the control unit 20 drives the second drive motor 12 at a rotational speed of the motor B (second rotational speed of the motor) higher than the rotational speed of the motor A. Accordingly, the second drive motor 12 is driven while alternately repeating the low-speed rotation at the rotational speed of the motor A and the high-speed rotation at the rotational speed of the motor B in accordance with the rotational movement of the crank shaft 17 about the central axis O of the drive shaft 16.

In the can making machine 1 of the present embodiment, the crank unit 8, which causes the processing table 2 to reciprocate in the direction of table axis TA with respect to the holding table 3, is driven by the first drive motor 11. The table index unit 9, which intermittently rotationally moves the holding table 3 about the table axis TA with respect to the processing table 2, is driven by the second drive motor 12. That is, the first drive motor 11 for driving the crank unit 8 and the second drive motor 12 for driving the table index unit 9 are provided separately (independently of each other). Therefore, unlike the conventional can making machine 100 shown in FIG. 7, since it is not necessary to mechanically connect the crank unit 101 and the table index unit 102, the following excellent operational effects are obtained.

That is, according to the present embodiment, while maintaining the constant speed at which the crank unit 8 is driven by the first drive motor 11 (the angular speed at which the crank shaft 17 is rotated about the drive shaft 16), it is possible to increase the speed (the angular velocity at which the holding table 3 is rotated about the table axis TA) at which the table index unit 9 is driven by the second drive motor 12. That is, it is possible to shorten the time required for rotationally moving the holding table 3 in the circumferential direction of the table by a predetermined amount during one stroke in which the processing table 2 reciprocates in the direction of the table axis TA. Accordingly, it is possible to reduce the angle range (i.e., the magnitude of the index period IP) of the index period (index angle) IP in the crank angle. Further, it is possible to increase the angle range of the dwell period DP (i.e., the magnitude of the dwell period DP) of the crank angle accordingly.

Specifically, as shown in the graph of FIG. 4 and in the following Table 1 as first to seventh examples of the present embodiment, a larger angle range of the dwell period DP of the crank angle (horizontal axis) can be secured than in the conventional comparative example. Further, by adjusting the rotational speed of the motor or the like of the second drive motor 12, the magnitude of the dwell period DP can be variously set. This makes it possible to increase and variously set the effective stroke. That is, according to the present embodiment, the effective stroke can be variously changed without changing the top dead center and the bottom dead center of the processing table 2 (that is, without changing the total length of the stroke). Further, it is possible to flexibly respond to the demand for increasing the processing height, such as performing the drawing process deeper than conventional cans, without requiring a large change in structure in the existing can making machine.

TABLE 1

Range
Magnitude
Magnitude

Effective
of dwell
of dwell
of index

stroke
period
period
period

(mm)
(°)
(°)
(°)

First example
180.38
47 to 313
266
94

Second example
175.62
50 to 310
260
100

Third example
170.67
53 to 307
254
106

Fourth example
165.55
56 to 304
248
112

Fifth example
160.27
59 to 301
242
118

Sixth example
149.35
65 to 295
230
130

Seventh example
139.95
70 to 290
220
140

Comparative
130.36
75 to 285
210
150

example

Specifically, in FIG. 4 and Table 1, in the conventional comparative example, the range of the dwell period DP is 75 to 285° (that is, the magnitude of the dwell period DP is 210°), the magnitude of the assignment angle IP is 150°, and the effective stroke is 130.36 mm. That is, the effective stroke of the comparative example is approximately 59% of the total stroke length (220 mm). Further, it is not possible to change the effective stroke. Meanwhile, in the first to seventh examples of the present embodiment, the magnitude of the dwell period DP exceeds 210° (specifically, variously set between 220° or more and 266° or less), the magnitude of index period IP is less than 150° (specifically, variously set between 94° or more and 140° or less), and the effective stroke exceeds 130.36 mm (specifically, variously set between 139.95 mm or more and 180.38 mm or less). Further, the effective stroke of the first example reaches approximately 82% of the total stroke length (220 mm), and remarkably increases compared to the effective stroke of the comparative example.

As described above, according to the present embodiment, it is possible to change the effective stroke with a simple structure and to make the bottle can (can) B of various processing heights without changing the top dead center and the bottom dead center of the processing table 2.

Further, in the present embodiment, the can making machine includes the detecting unit 19 capable of detecting the crank angle of the crank shaft 17, and the control unit 20 that controls the rotational speed of the second drive motor 12 based on the crank angle detected by the detecting unit 19. Specifically, when the crank angle detected by the detecting unit 19 is in the range of the index period IP, since the control unit 20 increases the rotational speed of the second drive motor 12 as compared with a case of the dwell period DP, the following operation and effect are achieved.

That is, in this case, the table index unit 9 rotates the holding table 3 about the table axis TA at a high speed when the crank angle is in the range of the index period IP. Thus, it is possible to reliably suppress the angle range of the index period IP of the crank angle. The angle range of the dwell period DP can be greatly ensured and the effective stroke can be enlarged accordingly.

Further, in the present embodiment, since the detecting unit 19 is an angular position detection sensor (rotational angle sensor) such as a rotary encoder or a resolver, it is easy to incorporate the detecting unit 19 with high precision and compact configuration into an apparatus, and it is easy to obtain and has good handleability.

Further, in the present embodiment, since the second drive motor 12 is a servomotor, it is possible to change the rotational speed of the motor, and it is possible to obtain the aforementioned operation and effect of the present embodiment with a simple structure.

In the present embodiment, the table index unit 9 and the wheel index unit 15 are driven by the same drive motor (the second drive motor 12). Accordingly, as shown in FIG. 5, by mechanically connecting the table index unit 9 and the wheel index unit 15 to each other through pulleys, belts and the like, it is possible to synchronously and intermittently rotate the holding table 3, the supply wheel 10 and the discharge wheel 14 reliably and simply.

Further, the present invention is not limited to the above embodiment, and various modifications can be made within a scope that does not depart from the gist of the present invention.

For example, in the above embodiment, the table index unit 9 and the wheel index unit 15 are driven by the second drive motor 12, but the present invention is not limited thereto. Here, FIG. 6 shows a modified example of the can making machine 1 described in the above embodiment. In this modified example, the table index unit 9 is driven by the second drive motor 12, and the wheel index unit 15 is driven by the third drive motor 13. The third drive motor 13 is a servomotor. Preferably, the third drive motor 13 is an AC servomotor. That is, in this modified example, the table index unit 9 and the wheel index unit 15 are not mechanically connected to each other. Further, when the crank angle detected by the detecting unit 19 is in the range of the index period IP, the control unit 20 increases the rotational speed of the motor with respect to the third drive motor 13 as compared to a case of the range of the dwell period DP.

Specifically, when the crank angle detected by the detecting unit 19 is in the range of the dwell period DP, the control unit 20 drives the third drive motor 13 at the rotational speed of the motor C (third rotational speed of the motor). Further, when the crank angle detected by the detecting unit 19 is in the range of the index period IP, the control unit 20 drives the third drive motor 13 at the rotational speed of the motor D (fourth rotational speed of the motor) higher than the rotational speed of the motor C. Accordingly, the third drive motor 13 is driven while alternately repeating the low-speed rotation at the rotational speed of the motor C and the high-speed rotation at the rotational speed of the motor D in accordance with the rotational movement of the crank shaft 17 about the central axis O of the drive shaft 16.

According to this modified example, the table index unit 9 is driven by the second drive motor 12, and the wheel index unit 15 is driven by the third drive motor 13. Therefore, it is possible to compactly suppress the performance and the external shape of each of the second drive motor 12 and the third drive motor 13, the range of component selection expands, and it is easy to fit the components in the apparatus. Further, since it is not necessary to mechanically connect the table index unit 9 and the wheel index unit 15 to each other, the structure of the apparatus is simplified. In the above description, the second drive motor 12 and the third drive motor 13 are servomotors, but the present invention is not limited thereto. That is, for example, there may be provided a configuration which mechanically changes the rotational speed transmitted to the table index unit 9 and the wheel index unit 15 from each of the drive motors 12 and 13, depending on whether the crank angle is in the range of the index period IP or in the range of the dwell period DP, using the drive motors 12 and 13 with the constant rotational speed of the motor.

Further, in the above embodiment, the detecting unit 19 is, for example, an angular position detection sensor (rotational angle sensor) such as a rotary encoder or a resolver, but the invention is not limited thereto. That is, the detecting unit 19 may be a position detection sensor or the like other than the angular position detection sensor.

In the above embodiment, an example of the bottle can making machine for making the bottle can B by performing various types of processing on the bottomed cylindrical body W has been described as the can making machine 1, but the present invention is not limited thereto. That is, for example, the can making machine 1 may be an aerosol can making machine that makes an aerosol can by performing various types of processing on the cylindrical body W, or may be a can making machine that makes a can other than the bottle can and the aerosol can. Further, the cylindrical body W is not limited to a bottomed cylindrical shape, and may be a simple cylindrical body having no bottom wall or the like.

Each configuration (constituent element) described in the above embodiments, modified examples, and writing may be combined, and additions, omissions, substitutions and other changes of configurations can be made, within the scope that does not depart from the gist of the present invention. Further, the present invention is not limited by the aforementioned embodiments, but is limited only by the claims.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.

REFERENCE SIGNS LIST

1: Can making machine

2: Processing table

3: Holding table

4: Main body frame

5: Shaft section

6: Processing tool

7: Chuck

8: Crank unit

9: Table index unit

10: Supply wheel

11: First drive motor

12: Second drive motor

13: Third drive motor

14: Discharge wheel

15: Wheel index unit

16: Drive shaft

17: Crank shaft

18: Connecting rod

19: Detecting unit

20: Control unit

DA: Wheel axes of discharge wheel

DP: Dwell period

IP: Index period (index angle)

O: Central axis of drive shaft

SA: Wheel axes of supply wheel

TA: Table axis

W: Cylindrical body (workpiece)

CAN MAKING MACHINE

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

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Abstract

Description

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Priority Claims (1)