JP3090257B2 - Machining center - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining center having a column for supporting a spindle and a table for setting a workpiece, wherein a relative position between the spindle and the table is controlled using first to sixth actuators. It is about.

[0002]

2. Description of the Related Art Conventionally, a spindle and a table of a machining center are relatively moved by using a so-called serial mechanism. In other words, the spindle and table are X,
The positioning operation has been performed by moving in the Y and Z axes and rotating about two orthogonal axes.

[0003]

The present inventors have attempted to configure a machine tool using a parallel mechanism completely different from the serial system.

The present invention is compact and has a large degree of freedom.
It aims to provide a versatile parallel machining center.

[0005]

The present invention comprises a column for supporting a spindle, and a table for setting a workpiece, wherein a relative position between the spindle and the table is controlled using first to sixth actuators. In the machining center, the supports (14, 114) are movably provided on the columns (12, 112), and the linear sixth actuators (36, 13) are provided.
6), the support (14, 114) is
112) relative to the sixth axis direction,
A rotating body (21, 121) is rotatably provided on the support (14, 114), and a rotary fourth actuator (34, 1) is provided.
34), the rotating body (21, 121) is supported by the support (1).
4, 114) relative to the fourth axis, and the first to third linear types are attached to the rotating body (21, 121) via universal joints (18 to 20, 118 to 120). Actuators (31-33, 131-1
33) and attach their spindle heads (2
8) to constitute a parallel mechanism, and the spindle heads (16, 11) with a built-in motor in the spindle heads (28, 128).
6), and a rotary fifth actuator (35, 1).
35) allows the orientation of the spindles (16, 116) to rotate around the fifth axis within the spindle head,
Servo controllers (41-46) for controlling the actuators (31-36, 131-136) are provided,
Using the principle of the parallel mechanism, the spindle (16, 11
The gist of the present invention is a machining center characterized in that the position / posture of 6) is controlled.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A machining center according to the present invention has a column for supporting a spindle and a table for setting a workpiece, and a relative position between the spindle and the table is controlled using first to sixth actuators. In the machining center, the support is movably provided on the column, and the linear type
The support is moved to the sixth position relative to the column by the actuator.
A rotatable member is provided on the support so as to be rotatable in the axial direction, and the rotary member can be rotated around the fourth axis relative to the support by a rotary type fourth actuator. The first to third linear actuators are mounted via a universal joint, and a spindle mechanism is provided at an output portion of the actuator to constitute a parallel mechanism. The actuator enables the orientation of the spindle to be rotated about the fifth axis within the spindle head, and
A servo controller for controlling the actuator is provided, and the position and orientation of the spindle are controlled using the principle of the parallel mechanism.

[0007] The machining center of the present invention can be called a parallel machining center because it utilizes the principle of the parallel mechanism.

[0008] The first to the first using a hollow shaft servomotor
Advantageously, the third actuator is formed, and the hollow shaft servomotor is configured such that a nut is mounted inside the hollow rotor and a ball screw is engaged with the nut.

The use of a hollow shaft servomotor eliminates the need for a shaft coupling, and allows the ball screw to penetrate the motor. The structure can be large.

A calculation unit may be connected to the servo controller so that the calculation unit performs inverse kinematics calculation for decomposing the target trajectory (target position / posture) of the spindle into the target trajectory of each actuator.

That is, the calculation section decomposes the target trajectory (target position / posture) of the spindle into the target trajectory (displacement) of each actuator by inverse kinematics calculation. Then, the obtained target trajectory of the actuator is sent to the servo controller of each actuator as a target value. Thereby, each actuator is controlled so as to follow the target trajectory in each servo system.

Such control is so-called semi-closed loop control. Although the position and attitude of the main shaft are not directly fed back, the parallel mechanism does not accumulate the motion error of each actuator, so that a large positioning error does not occur.

The machining center has an automatic tool change magazine, and performs automatic tool change between the spindle and the automatic tool change magazine using at least a part of the operation of the first to sixth actuators. Can be. Of course, an automatic tool change arm is provided, and
TC can also be performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are a front view, a side view, and a top view showing a machining center according to the present invention.

The machining center 10 includes a base 11 and
It has a table 13 and a column 12 set on a base.

A support 14 is provided on the column 12 so as to be vertically movable. The support 14 is moved by a linear type sixth actuator 36. The sixth axis direction is a vertical direction. In the drawing, the moving direction of the sixth actuator 36 is indicated by an arrow D6.

The sixth actuator 36 can be constructed using, for example, a feed screw and a nut. Preferably, a ball screw is used.

The support 14 is a generally annular guide member. On the support 14, an annular rotating body 21 is rotatably guided along the support 14. Rotating body 21
Is rotated in a fourth axial direction (arrow D4) by a rotary fourth actuator.

The fourth actuator comprises a worm wheel 59 and a worm 58 constituting a worm gear, and a servo motor 34 for driving the worm 58 to rotate.

The rotating body 21 is substantially configured as a worm wheel 59. Worm 58 supports 14
It is provided so as to be rotatable. The output shaft of the servomotor 34 is connected to one end of the worm 58.

When the servo motor 34 rotates, the rotating body 21 is moved in the fourth axial direction (arrow D) by the action of the worm gear.
4) Rotate.

Inside the rotating body 21, first to third linear type actuators 31 to 33 are supported at equal intervals via universal joints 18 to 20.

The first to third actuators are formed by using a hollow shaft servomotor 60.

The state of the first actuator 31 and the universal joint 18 is shown in FIGS.

The universal joint 18 has a rotating shaft 5
2,53. The first actuator is entirely rotatable around these rotation shafts 52 and 53.

The hollow shaft servomotor 60 includes a hollow rotor 63, a bearing 61 for supporting the rotor 63,
A stator 62 is provided to face the rotor 63.

Inside the hollow rotor 63, a nut 55 is provided.
Is attached integrally. The nut 55 has a nut 5
5 is engaged with the ball screw 54.

Below the hollow shaft servomotor 18, an outer cylinder 56 and an inner cylinder 57 are arranged to be extendable and contractible.
The front end of the ball screw 54 is fixed to the rear end of the inner cylinder 57. The tip of the inner cylinder 57 becomes the output section of the actuator. The outer cylinder 56 is fixed to the lower surface of the hollow shaft motor.

When the hollow shaft servomotor 18 is driven, the tip of the inner cylinder 57 moves in the first axial direction (arrow D1) by the action of the ball screw 54 and the nut 55.

Second and third actuators 32, 33
Has the same configuration as the first actuator 31.

The output portions of the first to third actuators 31 to 33 are integrally supported, and a spindle head 28 is provided there. Such a structure is considered as a kind of a so-called parallel mechanism.

The spindle head 28 includes a spindle stage 15, a spindle 16 with a built-in motor, and a fifth actuator 35 of a rotary type.

The main spindle stage 15 has a generally U-shaped cross section, and the rear ends thereof are connected to the output ends of the first to third actuators 31 to 33 as described above.

The spindle stage 15 is provided with a rotary type fifth actuator. The fifth actuator has a servomotor 35 whose output shaft is
6 is connected to the side. When the servo motor 35 is driven, the main shaft 16 rotates around the fifth axis and changes its direction as indicated by an arrow D5 in FIG.

In the neutral position shown in FIGS. 1 and 2,
The fourth axis and the fifth axis are orthogonal.

The main shaft 16 is of a motor-incorporated type as described above, and has a drive motor for rotating the tool T. The tool T (tool holder) can be detachably attached to the main shaft 16 in a usual manner.

The operation directions D1 to D3 of the first to third actuators 31 to 33 and the direction D5 of the rotation axis of the fifth actuator 35 change according to the operation of the first to fifth actuators themselves.

On the other hand, the operation direction D6 of the sixth actuator 36 is always the vertical direction. The operation direction D4 of the fourth actuator 34 is a rotation direction with the operation direction D6 as a central axis.

As shown in FIG. 6, the first to sixth actuators 31 to 36 include servo controllers 41 to 46.

The calculators 50 are connected to the servo controllers 41 to 46. The calculation unit 50 calculates the target trajectory (displacement) of each actuator from the target trajectory (target position / posture) of the spindle by inverse kinematics calculation.

Each of the servo controllers 41 to 46 controls each of the actuators 41 to 46 based on the target trajectory sent from the calculation unit 50.

Such control is so-called semi-closed loop control. Although the position and attitude of the main shaft are not directly fed back, the parallel mechanism does not accumulate the motion error of each actuator, so that a large positioning error does not occur.

An ATC magazine 51 is arranged beside the table 11. The ATC magazine 51 can accommodate a large number of tools (tool holders) in an indexable manner.

At the side of the ATC magazine 51, an automatic exchange arm is arranged as required, but is not shown in the drawing.

The tool can be exchanged between the ATC magazine 51 and the spindle 16 using the automatic exchange arm. When the degree of freedom of the parallel mechanism for controlling the position / posture of the main shaft 16 is increased, it is possible to directly perform tool change by moving the main shaft 16.

Next, a working example using the machining center of the present embodiment will be briefly described with reference to FIGS.

FIG. 7 shows an example of machining in which the main shaft 16 moves in a direction perpendicular to the table surface. In table 13,
The workpiece W is fixed by the jig 47. In this state,
By driving the sixth actuator downward, a hole can be formed in the work W in a direction perpendicular to the table surface.

FIG. 8 shows an example of machining performed by rotating the main shaft 16 by 90 degrees by the fifth actuator. The target trajectory input to the calculation unit 50 in this case is a horizontal trajectory. Servo controller 41 based on the calculation result
To 46, the first to sixth actuators 3
The holes 1 to 36 are operated as appropriate to form holes in the horizontal direction with respect to the table surface.

FIG. 9 shows an example of 5-axis machining. The target trajectory in this case is a trajectory that scans a predetermined curved surface. Commands are sent from the servo controllers 41 to 46 based on the result of the inverse kinematics calculation performed by the calculation unit 50, and the first
The sixth to third actuators 31 to 36 are appropriately operated to perform predetermined curved surface processing.

Next, another embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the orientation of the support 114 is different from that of the above-described embodiment. That is, the support body 114 of the present embodiment is arranged such that the support surface is in the vertical direction.
2 are arranged. Therefore, the rotation axis of the fourth actuator is horizontal.

On the other hand, it is also possible to adopt a configuration in which the direction of the support itself can be freely set by an actuator for the support.

In the embodiments shown in FIGS. 11 and 12, a linear type seventh actuator is provided on the base 111, so that the column (or table or ATC magazine) can be moved in the seventh axis direction. ing.

[0054]

According to the machining center of the present invention, it is possible to provide a high-precision machining center that is compact, has a high degree of freedom, and is versatile, taking advantage of the advantage of the parallel mechanism that the motion error of each actuator does not accumulate.

In the case where the first to third actuators are formed by using a hollow shaft servomotor as described in claim 2, a shaft coupling is not required, and the length of the ball screw can be effectively reduced. Since it can be used, a more compact parallel mechanism can be configured.

The present invention is not limited to the above embodiment. For example, the direction of the tool stored in the ATC magazine is
It is also possible to make it sideways instead of up and down.

Further, a rotating body may be provided on the outer periphery of the support, and the first to third actuators may be mounted outside the rotating body.

Further, the shape of the support for guiding the rotating body (worm wheel) does not need to be annular. For example, an arm having an arcuate guide may be used.

[Brief description of the drawings]

FIG. 1 is a front view showing a machining center according to an embodiment of the present invention.

FIG. 2 is a side view of the machining center of FIG. 1;

FIG. 3 is a top view of the machining center of FIG. 1;

FIG. 4 is a sectional view showing a first actuator and a universal joint of FIG. 1;

FIG. 5 is a side view of FIG. 4;

FIG. 6 is a diagram showing a control system of first to sixth actuators in FIG. 1;

FIG. 7 is a diagram showing a processing example using the machining center of FIG. 1;

FIG. 8 is a view showing another processing example.

FIG. 9 is a diagram showing still another processing example.

FIG. 10 is a front view showing another embodiment of the machining center of the present invention.

FIG. 11 is a side view of the machining center of FIG. 10;

[Description of Signs] 11, 111 Base 12, 112 Column 13, 113 Table 14, 114 Support 15, 115 Spindle Stage 16, 116 Spindle 18-20, 118-120 Universal Joint 31-36, 131-136 Actuator 41- 46 Servo controller 50 Calculation unit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kosaku Kitamura 1870 Todekomyoji Temple, Takaoka City, Toyama Prefecture, Japan Inside (72) Inventor Shigeru Yamada 1870 Todekomyoji Temple, Takaoka City, Toyama Prefecture, Japan Kitamura Machinery Corporation ( 72) Inventor Takashi Saito 1870 Todekomyoji Temple, Takaoka City, Toyama Prefecture Inside Kitamura Machine Co., Ltd. (56) References JP-A-9-136286 (JP, A) JP-A-9-150333 (JP, A) 6-190667 (JP, A) Special table Hei 5-500337 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23Q 1/00-1/76 B23Q 3 / 155,3 / 157 B23Q 15/00-15/28

Claims (4)

(57) [Claims] 1. A machining center having a column for supporting a spindle and a table for setting a workpiece, wherein a relative position between the spindle and the table is controlled using first to sixth actuators. ), A support (14, 114) is provided movably, and a linear-type sixth actuator (36, 114) is provided.
136), the support (14, 114) is
2 and 112), and a rotating body (21, 121) is rotatably provided on a support (14, 114), and a rotary fourth actuator (34, 1) is provided.
34), the rotating body (21, 121) is supported by the support (1).
4 and 114), and can be rotated around a fourth axis relative to the rotating body (21, 121) through the universal joints (18-20, 118-120). Actuator (31-33, 131-13
3) Attach the spindle head (28) to their output
Are provided to form a parallel mechanism. A spindle (16, 116) with a built-in motor is arranged on the spindle head (28, 128). The direction can be rotated around the fifth axis in the spindle head, and the first to sixth actuators (31 to 36, 131 to 13)
6) Servo controller (41-4) for controlling
A machining center provided with 6) and configured to control the position and orientation of the spindles (16, 116) using the principle of a parallel mechanism. 2. A first motor using a hollow shaft servomotor.
-3rd actuator (31-33, 131-133)
The hollow shaft servomotor is characterized in that a nut (55) is mounted inside a hollow rotor (63) and a ball screw (54) is engaged with the nut (55). The machining center according to claim 1, wherein: 3. A calculation unit (50) is connected to the servo controllers (41 to 46), and the calculation unit (50) reverses the target trajectory (target position / posture) of the spindle into target trajectories of the respective actuators. 3. The machining center according to claim 1, wherein the machining center is configured to perform kinematics calculation. 4. The machining center has an automatic tool change magazine (51, 151), and utilizes at least a part of the operation of the first to sixth actuators (31 to 36, 131 to 136) to operate the spindles (16, 151). The automatic tool exchange is performed between the automatic tool exchange magazine (116) and the automatic tool exchange magazine (51, 151).
The machining center according to the item.