JP4279632B2 - Press machine - Google Patents

Description

  The present invention relates to a press device used for, for example, sheet metal processing, and more particularly to a press device having a simple structure and capable of fixed point processing requiring accurate position control.

  Fixed-point machining by an electric press has been used conventionally, and is known to be advantageous in terms of preventing noise generation.

  According to the electric press that performs fixed point processing, fixed point processing can be performed without generating noise, but the conventional one has the following problems. That is, the height to the presser attached to the lower surface of the slide plate is controlled so as to be constant at all times because of fixed point machining. At this position, a predetermined pressing force is applied to the workpiece via the presser. Is applied. Therefore, a reaction force corresponding to the pressing force is always applied to the screw shaft and the nut that presses the pressing element and the movable body at the same relative position.

  On the other hand, the screw shaft and nut are used for ball screw engagement in order to accurately and accurately control the position of the ram shaft and the presser, and the ball and ball groove constituting the ball screw are in line contact or point contact. Is engaged. For this reason, if the reaction force is applied to the ball and the ball groove many times at the same relative position, the ball and / or the ball groove are locally worn, and the combination accuracy is lowered and the life is short. There is a problem. The same problem exists when the screw shaft and the nut are in normal screw engagement.

  In order to solve the above problem, the present applicant has already proposed press apparatuses described in Patent Document 1 and Patent Document 2.

  FIG. 4 is a front view of a main part longitudinal section showing an example of the press device disclosed in Patent Document 1, and FIG. 5 is a cross-sectional plan view of a main part taken along line 5-5 in FIG. In both figures, reference numeral 10 denotes a base, which is formed in, for example, a rectangular flat plate shape. For example, cylindrical guide bars 20 are erected at four corners thereof. A support plate 30 formed in, for example, a rectangular flat plate shape is fixed to the upper end portion of the guide bar 20 via, for example, a fastening member 33.

  Next, reference numeral 40 denotes a screw shaft, which is supported at the central portion of the support plate 30 through the bearing member 34 and through the support plate 30 so as to be able to rotate forward and backward. A movable body 50 is engaged with the guide bar 20 so as to be movable in the axial direction thereof. A spindle motor 31 is provided on the support plate 30 and rotates the screw shaft 40 to drive the movable body 50. Reference numeral 60 denotes a nut member, which is formed by integrally connecting a nut portion 62 having a flange portion 61 and a cylindrical portion 63 formed in a hollow cylindrical shape. The nut portion 62 is screwed with the screw shaft 40 by ball screw engagement, and a differential male screw 64 is provided on the outer peripheral surface of the cylindrical portion 63.

  Reference numeral 65 denotes a differential member, which is formed in a hollow cylindrical shape, and is provided with a differential female screw 66 that is screwed into the differential male screw 64 on the inner peripheral surface. Reference numeral 67 denotes a worm wheel which is integrally fixed to the differential member 65 and is formed so as to engage with the worm gear 68.

  A worm shaft is inserted into and fixed to the central portion of the worm gear 68, and both ends of the worm shaft are rotatably supported by bearings provided in the movable body 50. Reference numeral 69 denotes a motor, which is provided so that the worm shaft can be rotated. Reference numeral 91 denotes a presser, which is detachably provided on the lower surface of the central portion of the movable body 50. The spindle motor 31 and the motor 69 are configured to be controlled and driven by applying a predetermined signal via a control means (not shown).

With the above configuration, when a predetermined signal is supplied to the spindle motor 31 and operated, the screw shaft 40 rotates, the movable body 50 including the nut member 60 is lowered, and the presser 91 is moved from the initial height H _0. The workpiece is lowered to the fixed-point machining height H and comes into contact with the workpiece W. As a result, fixed-point machining is performed on the workpiece W with a pressing force set in advance via the pressing element 91. After machining end, the movable body 50 rises by the reverse rotation of the spindle motor 31, the presser 91 returns to the position of the initial height H _0. The values of H ₀ and H are measured by measuring means (not shown) and can be controlled even in relation to the spindle motor 31.

When the above-mentioned fixed point machining reaches a preset number of times, the motor that stops the operation of the spindle motor 31 and rotates the differential member 65 at the position shown in FIG. 4, that is, the position of the initial height H ₀ of the presser 91. A preset signal is supplied to 69. As a result, the motor 69 rotates by a predetermined angle, and the differential member 65 rotates by a predetermined angle via the worm gear 68 and the worm wheel 67. By the rotation of the differential member 65, the nut member 60 is stopped and locked, that is, the differential female screw 66 is rotated with respect to the stopped differential male screw 64. Displace.

The initial height H ₀ of the pressing member 91 naturally changes due to the displacement of the movable body 50. However, if the screw shaft 40 is rotated as it is, predetermined fixed point machining cannot be executed. For this reason, the next controlled slight signal is supplied to the spindle motor 31 to slightly rotate the screw shaft 40 to cancel the displacement of the movable body 50 and the pressing element 91, and the initial height of the pressing element 91. An operation for holding H ₀ constant is performed.

  The relative position between the screw shaft 40 and the nut portion 62 is changed by the rotation of the screw shaft 40. That is, the relative position between the ball and the ball groove formed in the ball screw engagement can be changed, and the local wear of the ball and / or the ball groove can be prevented while securing the fixed point processing.

  FIG. 6 is a cross-sectional front view of an essential part of another pressing apparatus described in Patent Document 2, and the same parts are denoted by the same reference numerals as those in FIGS. In FIG. 6, reference numeral 71 denotes a slide plate which is slidably engaged with the guide bar 20 and is provided so as to be movable up and down, and a pressing member 91 is fixed to the lower part. Reference numeral 92 denotes a table which is provided on the base 10 and on which the workpiece W is placed.

  Next, the movable body 50 is divided by a plane intersecting the moving direction (vertical direction in FIG. 6) of the movable body 50, for example, a horizontal plane, and the first movable body 53 and the second movable body which are arranged to face each other. 54. The first movable body 53 is fixed to the ball screw nut 52 and the second movable body 54 is fixed to the slide plate 71. Reference numeral 72 denotes a differential member, which is formed in a wedge shape, connects the first movable body 53 and the second movable body 54, and functions as described later.

  Reference numeral 73 denotes a motor, preferably a pulse motor, which is provided on the slide plate 71 via a support member 74, and is a direction perpendicular to the moving direction of the movable body 50 (the left-right direction in FIG. 6). It is for driving. That is, a screw shaft 75 is connected to the rotating shaft of the motor 73, and the screw shaft 75 is formed to be screwed with a nut member (not shown) provided in the differential member 72. . Reference numeral 76 denotes a guide plate, which is provided, for example, as a pair on both side surfaces of the first movable body 53 and the second movable body 54, and its lower end is fixed to the second movable body 54, and the vicinity of the upper end is the first. 1 movable body 53 is formed so as to be slidably engaged.

With the above configuration, when a predetermined signal is supplied to the spindle motor 31 and operated in FIG. 6, the screw shaft 40 rotates, and the first movable body 53, the second movable body 54, and the differential connecting them. The movable body 50 composed of the member 72 and the like is lowered, and a presser 91 similar to that shown in FIG. 4 is lowered from the initial height H ₀ to the fixed point machining height H, and fixed point machining is performed on the workpiece W. done, after processing ends, the movable member 50 is raised by reverse rotation of the spindle motor 31, the presser 91 returns to the position of the initial height H _0.

When the above-mentioned fixed point machining reaches a preset number of times, or every time the fixed point machining is performed, the operation of the spindle motor 31 is stopped at the position of the initial height H ₀ of the presser 91 and a signal set in advance to the motor 73 Supply. As a result, the motor 73 rotates by a predetermined angle, and the differential member 72 slightly moves in the horizontal direction via the screw shaft 75. By the movement of the differential member 72, the first movable body 53 and the second movable body 54 are relatively moved in the vertical direction, and the position of the movable body 50 is displaced. Correction operation for canceling the displacement is carried out by the supply of a signal to the spindle motor 31 is to hold the initial height H ₀ of the presser 91 to be constant.

By rotating the screw shaft 40 in accordance with the above correction, the relative position between the screw shaft 40 and the ball screw nut 52 changes, and the relative position between the ball formed in the ball screw engagement and the ball groove can be changed. Therefore, it is possible to prevent local wear of the ball and / or the ball groove while securing the fixed point processing, and the fixed point processing can be continuously performed thereafter.
JP 2000-218395 A JP 2002-144098 A

  As described above, the press devices described in Patent Document 1 and Patent Document 2 can change the relative positions of the ball and the ball groove engaged with the ball screw every time molding is performed several times. Therefore, local wear between the ball and the ball groove can be prevented. However, in the press apparatus disclosed in Patent Document 1, the movable member is heavy and large because the differential member 65, the motor 69 that moves the differential member, and the drive mechanism thereof are provided in the movable body. Yes. Further, in the press apparatus disclosed in Patent Document 2, the movable body is divided into first and second, and the differential mechanism is formed by integrating the guide body with the movable body. It has become a big thing. Since the movable body is so large and heavy, an unnecessary load is applied to the motor that drives the movable body, and the ball screw is also loaded when the movable body is pulled up. Further, since the movable body is heavy and has a large inertia, when the movable body is moved to control the position, a large torque is required and a time loss occurs.

  In addition, an encoder is attached to the motor to accurately control the rotation angle of the motor that moves the differential mechanism. However, since the encoder is susceptible to vibration and other factors, It is something that must be avoided.

  Accordingly, an object of the present invention is to provide a press equipped with a differential mechanism capable of changing the relative position between the ball screw engaging the ball screw of the screw shaft and the ball groove every time molding is performed several times. An apparatus is provided in which the weight of the movable body is the same as that having no differential mechanism.

  Another object of the present invention is to provide a pressing device having a structure in which vibration generated when a movable body, that is, a slide plate is driven to perform a molding operation does not affect the differential mechanism. It is.

The press device of the present invention comprises a base,
A support plate held substantially parallel to the base;
A movable body that can move up and down between the base and the support plate;
A spindle motor attached to the support plate;
In what has a screw shaft that is attached to the rotation shaft of the spindle motor and drives the movable body relative to the base by the rotation of the spindle motor,
The screw shaft is movable up and down with respect to the rotation shaft of the main shaft motor, and is attached to the rotation shaft by a spline and a coupling so as to rotate with the rotation shaft.
A differential cylinder that has a first screw on its outer surface and that moves up and down with the screw shaft while holding a thrust bearing coaxially with the first screw and holding the screw shaft rotatably ;
A second screw provided on the support plate and holding the differential cylinder by screwing the first screw of the differential cylinder;
It is attached to the support plate, having a motor for rotating against the differential cylinder to the support plate and the screw shaft,
A differential mechanism is provided that moves the differential cylinder up and down with respect to the support plate together with the screw shaft by rotation of the motor.

  The differential mechanism further includes a gear integrated with the differential cylinder, a worm gear attached to the rotating shaft of the motor, and a means for transmitting power between the worm gear and the differential cylindrical gear. be able to.

  The pressing device may further include a control unit for the differential mechanism, which controls the differential cylinder of the differential mechanism with respect to the support plate according to the movement of the movable body between the base and the support plate. Control to move.

  Thus, in the press device of the present invention, since the differential mechanism that changes the machining stroke of the movable body is attached to the fixed support plate, the structure of the movable body is the same as the movable body that does not have the differential mechanism. Could be the same. Therefore, the weight of the movable body can be reduced, and the inertia can be reduced. Further, since the differential mechanism has a structure in which vibration does not act, the operation error can be reduced and a structure having a long life can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing a pressing device according to an embodiment of the present invention using a partial cross section, and FIG. 2 shows a cross-sectional plan view of an essential part of line 2-2 in FIG. In these drawings, the same parts as those in FIGS. 4 to 6 are denoted by the same reference numerals. The press device includes a base 10 having a substantially rectangular shape, a guide bar 20 standing at four corners of the base, and a support plate 30 supported by the guide bar substantially parallel to the base 10. A movable body 50 (here, the movable body is also a slide plate) is provided so as to move up and down along the guide bar 20. A spindle motor 31 is attached to the support plate 30, and a screw shaft 40 of a press device extending from the rotation shaft of the spindle motor protrudes downward through the support plate 30. A ball screw 41 is provided at the tip of the screw shaft 40. A through hole 51 is formed at substantially the center of the movable body 50, and a ball screw nut 52 is fixed to the movable body 50 so as to be substantially concentric with the through hole 51. The ball screw 41 of the screw shaft 40 is engaged with a ball screw nut 52 provided on the movable body, and the movable body moves up and down by the rotation of the spindle motor 31, and the presser 91 or the gold attached to the movable body. Molding is performed by the mold.

  Since the movable body 50 to which the ball screw nut is attached has a through hole 51 substantially coaxially with the ball screw nut 52, the ball screw 41 of the screw shaft 40 is deeply screwed into the ball screw nut 52 and the ball screw The tip of the ball screw can protrude from the bottom of the nut 52.

  The screw shaft 40 of the pressing device extending from the main shaft motor 31 is rotatably held by a differential cylinder 81 attached to a support plate 30 in a through hole opened coaxially with the screw shaft 40. A thrust bearing 82 is attached to the through hole of the differential cylinder 81, and the screw shaft 40 is rotatably held. A first screw 83 (for example, a male screw) is provided coaxially with the through hole on the outer surface of the differential cylinder 81, and the first screw 83 is provided in a through hole opened in the support plate 30. The differential cylinder 81 is held on the second screw 32 of the support plate 30 by being screwed to the second screw 32 (for example, female screw). By rotating the differential cylinder 81 around its axis, the differential cylinder can be moved up and down together with the screw shaft 40 with respect to the support plate.

  The upper end of the screw shaft 40 is a spline 43 at a coupling 42 that connects the upper end of the screw shaft 40 to the rotating shaft of the main shaft motor 31. Since the screw shaft 40 is connected to the rotating shaft of the main shaft motor 31 by spline coupling, the rotation of the main shaft motor 31 is transmitted to the screw shaft 40 and the movable body 50 can be driven. However, even if the screw cylinder 40 is moved up and down by rotating the differential cylinder 81 with respect to the support plate 30, the movement is absorbed by the spline 43 and the coupling 42, so that the spindle motor 31 is affected. The screw shaft 40 can be moved up and down by rotating the differential cylinder 81.

  In the present invention, a motor 84 for rotating the differential cylinder 81 is attached to the support plate 30. Since the motor 84 preferably rotates by a predetermined angle when a predetermined signal is input, a pulse motor is suitable. In the embodiment shown in FIGS. 1 and 2, a worm gear 85 is attached to the rotating shaft of the motor 84, and the rotation is transmitted to the gear 87 integrated with the differential cylinder via the intermediate gear 86. . The motor 84, the worm gear 85, the intermediate gear 86, and the differential cylinder 81 constitute a differential mechanism 80, and the differential mechanism 80 is attached to the support plate 30.

A pressing element 91 or a mold for performing a forming process is attached between the movable body 50 and the base 10 of the pressing device, and the workpiece W is formed by the pressing element or the mold. When a drive signal is applied to the main shaft motor from the control means 100, the main shaft motor 31 rotates and the screw shaft 40 rotates, and a ball screw nut 52 engaged with a ball screw 41 provided on the screw shaft 40 is obtained. The movable body 50 descends via The pressing member 91 attached to the movable body descends from the initial height H ₀ to the fixed point processing height H and comes into contact with the workpiece W. As a result, fixed-point machining is performed on the workpiece W with a pressing force set in advance via the pressing element 91. When the spindle motor 31 is rotated in the reverse direction after the machining is completed, the movable body 50 is raised, and the pressing member 91 returns to the initial height H ₀ .

  When the molding process is performed a preset number of times N, a preset number of pulse signals are applied from the control means 100 to the motor 84 of the differential mechanism 80. By this pulse signal, the motor 84 rotates by a predetermined angle, and the differential cylinder 81 rotates by a predetermined angle via the worm gear 85, the intermediate gear 86, and the differential cylindrical gear 87. With this rotation, the differential cylinder 81 moves up or down by a predetermined distance with respect to the support plate 30, and the movable body 50 moves up or down by the same amount.

  Since the moving distance of the presser 91 after the movable body 50 moves up and down in this way until the molding process is changed by the distance moved by the differential cylinder 81, the spindle motor 31 rotates the ball screw 41 to perform the molding process. Then, the relative position between the screw and the nut at the machining position changes from before the movable body moves up and down.

Alternatively, after the movable body 50 moves up and down as described above, the spindle motor 31 is rotated so as to cancel the up-and-down movement, and the pressing member 91 is returned to the position of the initial height H ₀ . Thereafter, when the forming process is performed, the moving distance of the presser 91 until the forming process is the same as the initial one, but the screw shaft 40 is rotated to return the presser 91 to the position of the initial height H _0. Therefore, the relative position between the screw and the nut at the machining position changes from before the movable body 50 moves up and down. In this way, local wear of the ball and ball groove can be prevented.

  The operation of the differential mechanism 80 is shown in the flowchart of FIG. The control means 100 includes a counter C for the number of molding processes and a counter K for the number of times the motor of the differential mechanism is driven. These counters C and K are reset before the molding operation (step 101). . Each time the molding process (step 103) is performed according to the molding instruction (step 102), the counter C counts the number of moldings (step 104), and each time N molding processes are performed (step 105), the differential mechanism is activated. A preset number of pulse signals are supplied to the motor 84 of the differential mechanism (step 106), and for example, the differential cylinder 81 is moved upward by a predetermined amount. The amount by which the differential cylinder 81 is moved upward can be an amount by which each ball used in the ball screw 41 of the screw shaft 40 is rotated by an angle of several degrees. Each time the differential cylinder 81 is moved up, the number of movements is counted by the counter K (step 107), and if the ball moves once by A rotation (step 108), the motor is reversed (step 109). Can do. In steps 110 and 111, the counters K and C can be reset and the operation can be repeated.

It is a front view which shows the press apparatus by the Example of this invention using a partial cross section. FIG. 2 is a sectional plan view of an essential part of line 2-2 in FIG. It is a flowchart explaining the effect | action of the differential mechanism with which the press apparatus by the Example of this invention was equipped. It is a principal part longitudinal cross-section front view which shows the example of the press apparatus shown by patent document 1. FIG. FIG. 5 is a cross-sectional plan view of an essential part of line 5-5 in FIG. It is a principal part cross-sectional front view of another press apparatus described in patent document 2. FIG.

Explanation of symbols

10 base 20 guide bar 30 support plate 31 spindle motor 32 second screw (female screw)
33 fastening member 34 bearing member 40 screw shaft 41 ball screw 42 coupling 43 spline 50 movable body 51 through-hole 52 ball screw nut 53 first movable body 54 second movable body 60 nut member 61 collar portion 62 nut portion 63 cylinder Portion 64 Differential male screw 65, 72 Differential member 66 Differential female screw 67 Worm wheel 68, 85 Worm gear 69, 73, 84 Motor 71 Slide plate 74 Support member 75 Screw shaft 76 Guide plate 80 Differential mechanism 81 Difference Moving cylinder 82 Thrust bearing 83 First screw (male thread)
86 Intermediate gear 87 Gear 91 Presser 92 Table 100 Control means

Claims (3)

Base and
A support plate held substantially parallel to the base;
A movable body that can move up and down between the base and the support plate;
A spindle motor attached to the support plate;
In a press apparatus having a screw shaft that is attached to a rotation shaft of a main shaft motor and drives a movable body relative to a base by rotation of the main shaft motor.
The screw shaft is movable up and down with respect to the rotation shaft of the main shaft motor, and is attached to the rotation shaft by a spline and a coupling so as to rotate together with the rotation shaft.
A differential cylinder that has a first screw on its outer surface and that moves up and down with the screw shaft while holding a thrust bearing coaxially with the first screw and holding the screw shaft rotatably ;
A second screw provided on the support plate and holding the differential cylinder by screwing the first screw of the differential cylinder;
It is attached to the support plate, having a motor for rotating against the differential cylinder to the support plate and the screw shaft,
A press apparatus comprising a differential mechanism for moving a differential cylinder up and down with respect to a support plate together with a screw shaft by rotation of the motor. The differential mechanism further includes a gear integrated with the differential cylinder, a worm gear attached to the rotating shaft of the motor, and a means for transmitting power between the worm gear and the differential cylindrical gear. The press device according to claim 1. 3. A control means for moving the differential cylinder of the differential mechanism by a predetermined amount relative to the support plate according to the movement of the movable body between the base and the support plate. Press equipment.

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