JP3002459B2 - Multi-step machining center and its parallel mechanism structure - 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, and more particularly to a machining center capable of machining five surfaces by a single set-up so that not only a milling operation but also a complex process such as turning, boring, drilling, and grinding can be performed. And a multi-step machining center having such a parallel mechanism structure.

[0002]

2. Description of the Related Art In order to process a product having a desired shape and pattern using a machining center, it is necessary to control the three-dimensional position and orientation of a tool portion in the machining center. The most basic mechanical structure for this is a serial mechanism structure as shown in FIG. The series mechanism structure is a structure in which each axis from the base 1000 to the main shaft 1200 is at right angles. Such a serial mechanism structure has an advantage that a work space is wide and operation software and a control unit for operating the work space are simple.

In recent years, research on a machining center employing a parallel mechanism structure capable of six-degree-of-freedom movement has been actively conducted in comparison with such a series mechanism structure. The parallel mechanism structure is characterized in that the base and the main shaft are connected in parallel by a plurality of links.

FIG. 21 is a view illustrating a conventional parallel mechanism structure, that is, a hexapod structure. In the hexapod structure shown in FIG. 21, the base 2100 and the main shaft 2200 are connected by six links, and can perform six degrees of freedom motion by expanding and contracting the six links.

However, a machining center having a hexapod structure is divided into a vertical machining center and a horizontal machining center depending on the position of a spindle. Therefore, in the vertical machining center, it can not be processed only vertical surface of the workpiece, and since horizontal machining center can not be processed only horizontal plane of the workpiece, both the vertical plane and a horizontal plane in a single machining center Cannot be processed. In addition, since a turning process is not possible with a conventional machining center having a parallel mechanism structure, a separate operation using a lathe is required.

[0006]

SUMMARY OF THE INVENTION The present invention is to improve the above-described prior art parallel mechanism structure, and an object of the present invention is to increase the inclination of the main shaft as compared with the prior art. An object of the present invention is to provide a six-degree-of-freedom parallel mechanism structure.

Another object of the invention is a possible to the inclination of the main shaft 90 ° in the work space, since the spindle in this position can be pivoted around the workpiece, the vertical plane by a single machining center Another object of the present invention is to provide a parallel mechanism structure capable of not only processing a horizontal plane but also performing vertical turning.

It is still another object of the present invention to provide a six-axis machining center having the above-described six-degree-of-freedom parallel mechanism structure.

It is still another object of the present invention to provide an overdrive machining center for solving the singularity problem of the drive joint of the six-axis machining center.

[0010]

In order to achieve the above object, a parallel mechanism structure according to the present invention comprises three fixed length links connected to a main shaft in parallel with each other, and the three links are connected to each other. It includes three linear vertical guides for vertical transport, said vertical guide comprising a single circular horizontal guide capable of 360 ° equilibrium transport. The connection between the main shaft and the three fixed length links is made by a three-axis rotary joint, and the fixed length link and each linear vertical guide are connected by a one-axis rotary joint.
A linear uniaxial translation joint for the fixed length links to be vertically transported on respective linear vertical guides, and the three linear vertical guides for horizontal transport on the circular horizontal guide. Of the present invention includes an arc-shaped uniaxial translation joint.

When the parallel mechanism structure according to the present invention is used, not only is it possible to perform five-face machining with a single set-up, but also to perform multiple processes such as vertical turning, boring, drilling, and grinding. A process-type machining center can be realized.

A basic six-axis multi-step machining center embodied using the parallel mechanism structure according to the present invention is such that the three fixed-length links are vertically transferred on respective linear vertical guides. And three actuators driving a linear one-axis translation joint, and an arc-shaped one-axis translation so that the three linear vertical guides horizontally move on the circular horizontal guide. And three actuators for driving the transfer joint, with a total of six actuators driving six degrees of freedom movement of the tool.

The present invention also proposes an overdrive machining center in order to solve the singularity problem of the drive device which is likely to occur in the parallel mechanism structure. The 7-axis over-drive machining center proposed in the present invention is a three-axis machining center, in addition to the basic six actuators in the six-axis machining center.
An overdrive actuator that overdrives any one of the pivot joints;
A total of seven actuators drive six degrees of freedom movement of the tool. Such a seven-axis overdrive machining center can solve the singularity problem of the drive to some extent, but is not yet complete.

Therefore, the present invention proposes an eight-axis overdrive machining center that completely solves the singularity problem of the drive device. The 8-axis overdrive machining center is, besides the basic six actuators of the 6-axis machining center,
It includes two overdrive actuators that overdrive two of the three one-axis rotary joints, and drives a six-degree-of-freedom motion of the tool with a total of eight actuators. In such an 8-axis overdrive machining center, the problem of the singularity of the drive device does not occur at all.

Also, in the present invention, in consideration of the symmetry of the overdrive machining center, in order to enhance the strength of the machining center, a nine-axis actuator including three overdrive actuators that overdrive all of the three one-axis rotary joints is provided. An overdrive machining center is proposed.

According to the multi-step machining center embodying the parallel mechanism structure according to the present invention, five-sided machining can be performed by a single setup, and in particular, vertical turning can be performed.

[0017]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 11 shows a parallel mechanism structure according to the present invention. As shown in FIG. 1, three fixed length links 73, 74, 75 are connected to the main shaft 72. The lengths of the three fixed length links 73, 74, 75 may be the same or different from each other. FIG.
Shows a case where the lengths of the three fixed length links 73, 74, 75 are the same. These three fixed length links 73, 74, 75 are transported vertically along corresponding three linear vertical guides 83, 84, 85, respectively. The circular horizontal guide 76 allows the three linear vertical guides 83, 84, 85 to horizontally move 360 ° on an arc.

Main shaft 72, the three fixed length links 7
3, 74, 75, and three vertical guides 83, 84,
The connection between 85 and a single circular horizontal guide 76 will be described. The main shaft 72 and the three fixed length links 73, 74, 75
The fixed length links 73, 74, and 75 are connected to the corresponding vertical guides 83, 84, and 85 by uniaxial rotating joints R. Further, the fixed length links 73, 74, 75
Correspond to the respective linear vertical guides 83, 84, 8
In order to be transported vertically on 5, the one-axis rotating joint R
It is connected to a linear vertical guide by a linear one-axis translation transfer joint P. The three linear vertical guides 83, 8
The four linear guides 83, 84, 85 are used for horizontal transfer on the circular horizontal guide 76.
And the circular horizontal guide 76 are connected by an arc-shaped one-axis translational transfer joint P ′.

The basic drive joint of the above-described parallel mechanism structure is to vertically transfer the three fixed length links 73, 74, 75 on three linear vertical guides 83, 84, 85. And a one-axis translational transfer joint P ′ for transferring the three linear vertical guides 83, 84, 85 horizontally on the circular horizontal guide 76. is there. In this manner, the six joints can be driven to realize the basic six-degree-of-freedom movement of the main shaft.

In the parallel mechanism structure according to the present invention, two of the three linear vertical guides 83, 84, 85 are used to prevent the working space from becoming narrow.
Is arranged above with reference to the circular horizontal guide 76,
The other one 85 is arranged below.

FIG. 2 shows the parallel mechanism structure according to the present invention shown in FIG. 1, in which the inclination of the main shaft is 90 °. As shown in FIG. 2, in the parallel mechanism structure according to the present invention, a movement in which the inclination of the main shaft is 90 ° is possible. In the conventional parallel mechanism structure, it was difficult to increase the inclination of the main shaft to 90 °. This is because there is a limit to the rotation angle of the three-axis rotary joint that connects the main shaft and the plurality of links.

FIG. 3 is a plan view showing the parallel mechanism structure according to the present invention shown in FIG. 1 and showing that the tool turns around the workpiece when the inclination of the main shaft is 90 °. As shown in FIG. 3, the first, second, and third fixed length links maintain their relative positions even when the main shaft is turned from the first position to the second position in a state where the main shaft is inclined at 90 degrees. Then, since the three linear vertical guides transfer the circular horizontal guides, there is no change in the angle of the three-axis rotary joint S connecting the main shaft and the three fixed length links.

Hereinafter, a multi-step machining center embodying the above-described parallel mechanism structure according to the present invention will be described in detail with reference to FIGS.

FIG. 4 is a perspective view of a six-axis multi-step machining center in which the parallel mechanism structure according to the present invention is embodied.
5 is a plan view of FIG. 4, and FIG. 6 is a sectional view taken along line AA of FIG.

The multi-step machining center according to the present invention comprises a tool 1 and a spindle motor 2 for driving the rotary motion of the tool.
And a transfer system that determines the position and orientation of the tool.

Three fixed length links 401, 402, 4
Numeral 03 is connected to the main shaft system by three-axis rotating joints 301, 302 and 303. Three fixed length links 401, 40
The lengths of 2,403 may be the same or different from each other. FIG. 4 shows three fixed length links 40.
This is the case where the lengths of 1, 402 and 403 are the same.
The three-axis rotating joints 301, 302 used here,
303 is specially manufactured so that the allowable tilt angle is 60 ° or more, and the allowable tilt angle is larger than the maximum allowable tilt angle of the conventional three-axis rotary joint is about 50 °. There is an advantage.

Three fixed length links 401, 402, 4
03 denotes corresponding one-axis rotary joints 501, 502, 503
The respective linear vertical guides 601, 602,
603. Single axis rotary joints 501, 50
Three fixed length links 401 connected to 2,503,
The vertical transfer of 402 and 403 is driven by the respective vertical transfer actuators 701, 702 and 703. The linear vertical guides 601, 602, 603 are arranged two upward linear vertical guides 602, 603 arranged above with reference to the circular horizontal guide 8 and arranged downward with reference to the circular horizontal guide 8. And one downward-facing linear vertical guide 601. As another example,
One linear vertical guide may be configured upwards, and the other two linear vertical guides may be configured downwards.

FIG. 7 is a sectional view taken along the line BB of FIG.
FIG. 8 is a cross-sectional view of the upward vertical guide, and FIG.
FIG. 4 is a cross-sectional view of the downward-type vertical guide taken along a line.

Linear vertical guides 601, 602, 603
Are vertical actuators 701, 70
2, 703 each fixed length link 401,
Ball screw 62 for vertically transporting 402 and 403
1, 622, 623, each fixed length link 401, 40
2-axis joints 501, 502 connected to
Ball nuts 611, 612, 613 for connecting the 503 and the ball screws 621, 622, 623, and the ball screws 621, 622, 623 and the respective vertical transfer actuators 701, 702;
Couplings 631, 632, 63 connecting
3

Vertical transfer actuators 701, 70
2 and 703 are driven by ball screws 621 and 6
Ball nuts 611, 612, 6 through 22, 623
13 and the ball nuts 611, 612, 613
Are transmitted to the fixed length links 401, 402, 403 through uniaxial rotary joints 501, 502, 503 connected to the fixed length links 401, 402, 403, and as a result, the fixed length links 401, 402, 403 are provided by the ball screws 621, 622, 623. Is transferred along the vertical transfer path.

The linear vertical guides 601, 602,
603 is a horizontal transfer actuator 90
Driven by 1, 902 and 903, they are horizontally transferred on the circular horizontal guide 8. For such horizontal transfer, a ring gear 81 is disposed on the outer surface of the circular horizontal guide 8, and horizontal transfer actuators 901, 902, 903 are provided on the linear vertical guides 601, 602, 603.
Gears 821, 822, 82 driven by
3 are provided. Horizontal transfer actuator 90
1, 902, 903 are pinion gears 821, 822, 8
23, and the pinion gears 821, 822, 823
Are rotated in mesh with the ring gear 81, and the linear vertical guides 601, 602, and 603 are horizontally transferred.

The vertical load of the fixed length links 401, 402, 403 during vertical transfer and the linear vertical guide 60
Rollers 83 are provided to withstand the horizontal centrifugal force of 1,602,603 itself during horizontal transfer and the horizontal or vertical internal force between the steel bodies.

As described above, the vertical transfer of the three fixed length links 401, 402, 403 on the linear vertical guides 601, 602, 603, and the transfer of the three linear vertical guides 601, 602, 603. Circular horizontal guide 8
The position and orientation of the tool are determined by the six degrees of freedom movement of the main shaft constituted by the horizontal transfer above. As shown in FIG. 4, when six actuators including three vertical transfer actuators and three horizontal transfer actuators are included, this is called a 6-axis machining center.

In such a 6-axis machining center, the trajectory of the position and orientation of the tool is determined by the rotational movement components of the vertical transfer actuator and the horizontal transfer actuator. The input value of each transfer actuator determined through the above is numerically controlled, and the relative position and posture of the tool with respect to the workpiece are controlled to obtain a product having a desired shape.

As shown in FIG. 9, in the six-axis multi-step machining center according to the present invention, the main spindle can have a vertical posture with respect to the workpiece, so that it is possible to perform side machining of the workpiece by a single setup. is there.

On the other hand, the most restrictive factors for determining the position and orientation of the tool in the multi-step machining center according to the present invention are the fixed length links 401, 402,
3-axis rotary joints 301 and 30 connecting 403 to the spindle system
2, 303 rotation angles. In the present invention, the fixed-length links 401, 402, 403
1, 602, 603 to limit the vertical transfer range,
The three-axis rotating joints 301, 302, and 303 are not forced. To this end, each straight vertical guide 60
1, 602 and 603 are provided with limit switches 11 for restricting vertical transfer of fixed length links.

In the six-axis multi-step machining center according to the present invention, three linear vertical guides 601, 602, 6
03 denotes the horizontal transfer actuators 901 and 9 respectively.
02, 903, and moves 360 ° horizontally on the circular horizontal guide 8, so that the linear vertical guide 601,
It is necessary to respond to the situation where 602 and 603 collide. Therefore, in the present invention, the linear vertical guide 601,
602 and 603 are provided with limit switches 10 and 1 for preventing collision.
0 'is provided.

Since the driving of the computer numerical control multi-step machining center is generally controlled by a displacement value with respect to an initial value determined by the initial position and posture of the tool, it is necessary to determine an origin for determining the initial value. For this purpose, in the present invention, a limit switch 12 for horizontal transfer origin return and a limit switch 13 for vertical transfer origin return are provided.

The six-axis multi-step machining center according to the present invention is not limited to the above-described main spindle system and transfer system.
It further includes a workpiece rotation system for rotating the workpiece itself. The workpiece rotation system rotates a fixing member 31 for fixing the workpiece 20, a chuck 32 supporting the fixing member 31, a pneumatic cylinder 35 connected to the chuck 32, and the chuck. Pulley 3 for
3 and a pulley driving motor 36 for driving the pulley 33 described above. If the pulley drive motor 36 is not a direct connection type, the pulley drive motor 36
V- for transmitting the rotational driving force to the pulley 33 described above.
A belt 34 may be further included.

Including such a work rotating system, FIG.
As shown in the figure, the main axis is perpendicular to the workpiece,
Vertical turning can be performed while rotating the workpiece.

On the other hand, the parallel mechanism structure according to the present invention may have a problem of a drive unit singularity. The singularity problem of the drive device having the parallel mechanism structure is solved as follows.

The constraint equation of the parallel mechanism structure can be expressed as follows.

G (u, v) = 0, u∈R ⁿ , v∈R ^m , g; R ⁿ × R ^m → R ^m Here, u means a driving joint, and v means a passive joint.

From the above equations, it can be seen that the joint space forms an n-dimensional manifold located in an (n + m) -dimensional space.

If ∂g / ∂v is given by the implicit function theorem,
If it can be converted, v can be expressed as a function of u.

If the order of ∂g / ∂v is far apart and v is u
If it cannot be expressed by the function, all the driving joints cannot be driven independently. This is called a driving device singularity. Physically, no reaction force can be generated against an external force at such a singularity, so that the device is locally fuzzy.

The singularity of the drive unit of the six-axis machining center according to the present invention will be examined.

FIG. 10 shows a six-axis machining center according to the present invention shown in FIGS.
FIG. 6 shows the Jacobian state obtained by differentiating the above-mentioned constraint equation with respect to the passive joint variables when tilting from 90 ° to 90 °.
In FIG. 10, the horizontal axis is the inclination angle of the main shaft, and the vertical axis is the rotation angle γ of the main shaft itself.

In FIG. 10, the area displayed in a light color is a preferable state in which the main axis can be smoothly tilted.
The region displayed in dark color is the position where the singular point of the driving device exists, and at this singular point, it is impossible to drive all the driving joints independently, so that Become.

It can be seen that when the rotation angle γ of the main shaft is 0 °, singularities occur around 36 ° and 57 ° of the main shaft inclination angle. Such a singular point region displayed in dark color in FIG. 10 always occurs when the inclination angle of the main axis is inclined from 0 ° to 90 °, regardless of the rotation angle γ of the main axis. That is, even if the spindle rotation angle γ, which is an extra degree of freedom obtained by rotating the spindle itself, cannot be used to avoid a singular point of the drive device.

[0051] Thus, in the present invention, in order to solve the singular point problem of the driving device, in addition to the six actuators for driving the six drive joints, originally Actuator
Drive driving dynamic (excess passive joint that is not driven by eta
The present invention proposes an overdriven machining center including an additional actuator for moving . At least one actuator is added in the present invention.

First, a seven-axis machining center equipped with one overdrive actuator will be described in detail as one embodiment of the present invention.

FIG. 11 shows a passive joint to which an overdrive actuator can be mounted. One-axis rotary joint 5 of linear vertical guides 331, 332, 333 in a six-axis machining center
1, 52 and 53 are passive joints. In the 7-axis machining center, an overdrive actuator is attached to one of the one-axis rotary joints 51, 52, and 53, and the
The shaft rotating joints 51, 52, 53 are driven. Due to the symmetrical structure, the overdrive actuator is preferably mounted on the uniaxial rotary joint 51 of the downward linear vertical guide 331.

FIG. 12 shows a 7-axis machining center in which an overdrive actuator is mounted on a single-axis rotary joint of a downward linear vertical guide, and the inclination angle of the main shaft is from 0 ° to 9 °.
When the angle is tilted to 0 °, the state of Jacobian obtained by differentiating the constraint equation with respect to a passive joint variable is displayed. In FIG. 12, the horizontal axis is the inclination angle of the main shaft, and the vertical axis is the rotation angle γ of the main shaft itself. As shown in FIG. 12, in the case of the 7-axis machining center, it is understood that the singular point region disappears, and a singular point exists as a point instead. In addition, although the inclination angle of the main axis is around 36 ° is not a singular point region, it is understood that the state is still not good.

This problem can be solved by further adding an overdrive actuator.

Therefore, the present invention proposes an 8-axis machining center to which two overdrive actuators are added. In order to select the passive joint to which the overdrive actuator is added, each passive joint 51, 52 shown in FIG.
A sensitivity experiment for 53 was performed.

Each passive joint 51, 52 shown in FIG.
Of the 53, the one-axis rotating joint 51 of the downward linear vertical guide 331 is called the first passive joint, and the one-axis rotating joint 52 of the upward linear vertical guide 332 is called the second passive joint. The one-axis rotating joint 53 of the other upward linear linear guide 333 is referred to as a third passive joint.

FIG. 13 shows the sensitivity of each passive joint obtained along the left singular point region (the inclination angle of the main axis is about 36 °) shown in FIG. 10, and FIG. The sensitivity of each passive joint is obtained while moving along the right singularity region (the inclination angle of the main axis is about 55 °) shown in FIG.

As shown in FIG. 13, the sensitivity of the first passive joint 51 is much smaller than the sensitivity of the other passive joints 52 and 53 for the left singularity region, It can be seen that the sensitivity increases as the rotation angle increases. However, as shown in FIG. 14, the sensitivity of the second passive joint 52 and the third passive joint 53 is smaller than the sensitivity of the first passive joint 51 for the right singularity region. I understand.

As can be seen from FIGS. 13 and 14, in the case of a seven-axis machining center in which one overdrive actuator is mounted on the first passive joint 51, the singularity problem of the driving device when the inclination angle of the main shaft is around 37 ° is solved. It cannot be completely solved.

In the 8-axis machining center proposed in the present invention, the first overdrive actuator is mounted on the first passive joint 51 which is a single-axis rotating joint of a downward linear vertical guide, and the second overdrive actuator is mounted on the second overdrive actuator. The drive actuator is mounted on a one-axis rotary joint of one of the two upward linear vertical guides.
That is, the second overdrive actuator may be mounted on the second passive joint 52 or the third passive joint 53.

In the 8-axis overdrive machining center according to the present invention, it was observed that the singular point of the drive device disappeared and the inclination angle of the main shaft was smoothly inclined from 0 ° to 90 °.

Next, an eight-axis overdrive machining center according to the present invention will be described in detail with reference to FIGS.

FIG. 15 is a perspective view of an 8-axis overdrive machining center according to the present invention, FIG. 16 is a plan view of the 8-axis machining center of FIG. 15, and FIG. 17 is a sectional view taken along line AA of FIG. FIG. 18 is a detailed view of an upward-facing linear vertical guide of an 8-axis overdrive machining center according to the present invention. FIG.
FIG. 3 is a detailed view of a downward linear vertical guide of an 8-axis overdrive machining center according to the present invention.

The 8-axis overdrive machining center is, like a general machining center, a spindle system composed of a tool and a spindle motor 38 for driving the rotation of the tool, a transfer system for determining the position and orientation of the tool, and a workpiece to be machined. It is composed of a workpiece rotation system for rotating the workpiece.

In particular, the transfer system for determining the position and orientation of the tool includes three vertical transfer actuators 111, 11
2, 113 and three horizontal transfer actuators 121,
122, 123, two overdrive actuators 130, 1
31 and a total of eight actuators.

The three vertical transfer actuators 111,
112, 113 are fixed length links 351, 352, 3
Drive 53 to move on a linear vertical guide.
The rotational driving force of the vertical transfer actuators 111, 112, 113 is transmitted to the ball nut 91 through the respective ball screws 92, and fixed length links 351, through uniaxial rotating joints 361, 362, 363 connected to the ball nut 91. 352, 353, resulting in the fixed length links 351, 352, 353 moving along the vertical transport path provided by the ball screw 92.

Three horizontal transfer actuators 121,
122, 123 drive each linear vertical guide to move along the circumferential path provided by the circular horizontal guide 31.

The first overdrive actuator 130 overdrives the one-axis rotary joint of the downward linear vertical guide 331, and the second overdrive actuator 131 drives the one-axis rotary joint of the upward linear vertical guide 332. Overdrive.

Two additional overdrive actuators 1
30 and 131 completely solved the singularity problem of the drive unit, and solved the phenomenon that the inclination angle of the main shaft was inclined from 0 ° to 90 ° in a short time.

In consideration of the symmetry of the overdrive machining center, in order to further enhance the toughness, the present invention also proposes a 9-axis machining center in which all the one-axis rotary joints of the three linear vertical guides are equipped with overdrive actuators. I do. The 9-axis machining center controls the position and orientation of the tool using nine actuators.

[0072]

As described above, the overdrive machining center according to the present invention solves the singularity problem of the drive device that can be provided by the parallel mechanism structure, and performs the turning operation in a state where the inclination of the main shaft is 90 °. It can be so.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a parallel mechanism structure according to the present invention.

FIG. 2 shows a parallel mechanism structure according to the present invention shown in FIG. 1;
It is a perspective view explaining the case where the inclination of a main shaft is 90 degrees.

FIG. 3 shows a parallel mechanism structure according to the present invention shown in FIG. 1;
It is a top view showing that a tool turns around a work in a state where the inclination of a main axis is 90 degrees.

FIG. 4 is a perspective view of a six-axis multi-step machining center embodying a parallel mechanism structure according to the present invention;

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

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a cross-sectional view taken along line BB of FIG. 6, and is a cross-sectional view of an upward vertical guide.

FIG. 8 is a cross-sectional view taken along line BB of FIG. 6, and is a cross-sectional view of a downward vertical guide.

FIG. 9 is a perspective view of the six-axis multi-step machining center shown in FIG. 4, when the inclination of the main shaft is 90 °.

FIG. 10 is a six-axis machining center according to the present invention shown in FIGS. 4 to 9, wherein the inclination angle of the main shaft is from 0 ° to 90 °;
9 is a graph showing the state of Jacobian obtained by differentiating the constraint equation with respect to a passive joint variable when tilting to °.

FIG. 11 is a perspective view illustrating a passive joint to which an overdrive actuator can be mounted.

FIG. 12 is a 7-axis machining center in which an overdrive actuator is mounted on a single-axis rotating joint of a downward-facing linear vertical guide, and when the inclination angle of the main shaft is inclined from 0 ° to 90 °, the above-mentioned constraint type is used as a passive joint. It is a graph showing the state of Jacobian differentiated with respect to the variable.

FIG. 13 is a graph showing the sensitivity of each passive joint while moving along the left singular point region (the inclination angle of the main axis is about 36 °) shown in FIG. 10;

FIG. 14 is a graph showing the sensitivity of each passive joint while moving along the right singularity region (the inclination angle of the main axis is about 55 °) shown in FIG. 10;

FIG. 15 is a perspective view of an eight-axis overdrive machining center according to the present invention.

FIG. 16 is a plan view of the eight-axis overdrive machining center of FIG. 15;

FIG. 17 is a sectional view taken along line AA of FIG. 16;

FIG. 18 is a side view showing details of an upward-facing linear vertical guide of an 8-axis overdrive machining center according to the present invention.

FIG. 19 is a side view showing details of a downward linear vertical guide of an 8-axis overdrive machining center according to the present invention.

FIG. 20 is a perspective view showing a serial mechanism structure according to the related art.

FIG. 21 is a perspective view illustrating a conventional hexapod-type parallel mechanism structure.

[Explanation of symbols]

 1: Tool 2: Spindle motor 8, 76: Circular horizontal guide 10, 10 ', 11, 12, 13: Limit switch 20: Workpiece 31: Fixed member 32: Chuck 33: Pulley 34: V-belt 36: Motor 72: Main shaft 73, 74, 75: Fixed length link 81: Ring gear 83, 84, 85: Linear horizontal guide 91: Ball nut 92: Ball screw 130: Overdrive actuator

Continuing on the front page (72) Inventor Jung-Woo Park South Korea 135-080 Seoul Gangnam-ku Yeoksam-dong 789-29 (72) Inventor Wok-Kwan Bae South Korea 431-053 Kunki-Dou Anyang-Shi Donggang-ku Bissang 3- Dong Samho Apartment 17-109 (72) Inventor Seong-Jun Ryu South Korea 138-200 Seoul Songpaak Munjong-Don Family Apartment 215-703 (72) Inventor Jinwook Kim South Korea 122-010 Seoul Yung-pyong Yungam-Dong 116-8 (72) Inventor Jae-Chul Hwang Republic of Korea 151-061 Seoul Kuwanak-Buk Chong-Chung 11-Dong 196-238 (72) Inventor Jang-bum Park Korea 609-312 Busan Keung-Jung-Kuk- 2-Don 184-26 (72) Inventor Han-San Cho South Korea 122-070 Seoul Yun-pyeong −Guyukchon-Dong 32−42 (72) Inventor Guy Yang Lee Korea 158−096 Seoul Yanchong−Q Singhwall−Dong Shinnan Yaks-Apartment 3-502 (72) Inventor Kihari Korea 152−059 Seoul Kuro −Cro-Bong-Dong 443−51 (72) Inventor Yong-Hung Lee South Korea 137-041 Seoul Seocho-ku Bumpo-1-Dong Dhu-Gong-Apartment 344-401 (72) Inventor Cornell Ilascu South Korea 110-510 Seoul Chong-Lo 452 (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23P 23/02 B23P 23/00 B25J 11/00

Claims (11)

(57) [Claims] A base and a plurality of spindles for determining a position and a posture of a tool of a multi-step machining center are provided.
In a parallel mechanism structure connected in parallel by three links, three fixed length links connected to the main shaft of the tool, and three fixed length links each for transferring the three fixed length links in the vertical direction. A parallel machining structure for a multi-stage machining center , comprising: a linear vertical guide; and a single circular horizontal guide capable of horizontally moving the circular vertical guide 360 ° on an arc. 2. The three fixed length links are connected to the main shaft by a three-axis rotary joint, and each of the fixed length links and the corresponding linear vertical guides are connected by a one-axis rotary joint. A linear uniaxial translation joint for the fixed length link to be vertically transported on a corresponding respective linear vertical guide; and the three linear vertical guides on the circular horizontal guide. The parallel mechanism structure of a multi-step machining center according to claim 1, further comprising a uniaxial translational transfer joint on an arc for horizontal transfer. 3. The multi-step machining in accordance with claim 1, wherein said three fixed length links have the same length.
Guscenter parallel mechanism structure. 4. The multi-step machining machine according to claim 1, wherein the lengths of the three fixed length links are different from each other.
Parallel center mechanism structure. 5. The three linear vertical guides include: one downward linear vertical guide positioned below the circular horizontal guide; and two downward linear guides positioned above the circular horizontal guide. 2. The multi-step machining center according to claim 1, wherein the machining center comprises a plurality of upwardly directed vertical guides.
Parallel mechanism structure of the data. 6. A multi-step machining center embodying a parallel mechanism structure, comprising: three fixed-length links connected to a main shaft of a tool; and each of the three fixed-length links for vertically transferring the three fixed-length links. And three single linear vertical guides, wherein said linear vertical guides are capable of horizontally moving 360 ° on an arc, and wherein said three fixed length links comprise: Each linear vertical guide connected to the main shaft by a three-axis rotary joint and corresponding to the fixed-length link is connected to the main shaft by a single-axis rotary joint and each linear vertical guide to the fixed-length link. Three linear uniaxial translational joints for vertical transfer on the three linear vertical guides, and three arcuate ones for horizontal transfer on the circular horizontal guide. A parallel mechanism structure including an axial translation joint, wherein the three linear actuators respectively drive the three linear one-axis translation joints, and the three arc-shaped ones. A multi-process machining center comprising: three horizontal transfer actuators for driving an axial translation transfer joint; and a total of six actuators for driving six degrees of freedom movement of the tool. 7. The multi-step machining center according to claim 1, further comprising a seventh actuator for driving the one-axis rotary joint of any one of the three linear vertical guides over a single-axis rotary joint. The machining center according to claim 6. 8. The seventh actuator overdrives the one-axis rotary joint of one downward linear vertical guide, which is located below the circular horizontal guide, among the three linear vertical guides. 8. The multi-step machining center according to claim 7, wherein the machining is performed. 9. The multi-step machining center according to claim 7, further comprising: seventh and eighth overdrives each one-axis rotary joint of two linear vertical guides of said three linear vertical guides.
7. The system according to claim 6, further comprising a third actuator.
The multi-step machining center described in the above. 10. The two overdriven actuators, wherein one of the overdriven actuators is one of a downward linear vertical guide positioned below a circular horizontal guide among three linear vertical guides. One of the two upward linear vertical guides that overdrives the pivot joint and the remaining overdrive actuator is located above the circular horizontal guide among the three linear vertical guides 10. The multi-step machining center according to claim 9, wherein the one-axis rotary joint of one linear vertical guide is overdriven. 11. The multi-process machining center according to claim 6, wherein the multi-process machining center further includes three overdrive actuators for overdriving respective one-axis rotary joints of the three linear vertical guides. Machining center.