CN101618517B - Feeding system consisting of multi-drive elements - Google Patents

Abstract

The invention discloses a feeding system composed of multiple drive units, including a workbench, which is connected to a base body through guide rails. The double drive units are respectively arranged on both sides of the upper part of the workbench, and another drive unit is arranged on the lower part of the workbench. The feed system structure of the present invention realizes that when the position of the center of gravity of the workbench changes arbitrarily in a plane perpendicular to the direction of the driving force, the torque relative to the center of gravity formed by the driving force and external force is compensated, and the mechanical vibration of the feed system is suppressed to the greatest extent; it can improve Feed system acceleration; can improve the surface quality of workpiece processing.

Description

Feed system composed of multiple drive units

Technical field:

The invention relates to the field of mechanical structure design of a feed system, in particular to the arrangement of a feed platform drive unit (servo motor + ball screw or linear motor and other drive force output systems) and platform structure in the field of numerically controlled machine tools.

Background technique:

In the field of CNC machine tools, the feed system that carries workpieces, spindles and turntables is widely used. In high-speed and high-precision CNC machining centers, higher requirements are put forward for the acceleration, feed speed and accuracy of the feed system. Traditional single servo motor + ball screw or linear motor directly drives the feed system (take the ball screw as an example). Because there are machine parts in the middle of the workbench, or considering factors such as the rigidity of the platform structure, the drive unit cannot directly pass through its center of gravity W. At high cutting speeds, especially at high feed rates, there is a tendency to twist moving parts. The above-mentioned inevitable torsional movement and the inertial effect due to the moving parts will cause the vibration of the machine tool, and even bend and deform the machine tool components such as the machine tool bed or castings such as columns.

At present, there are three ways to solve the above problems. One is to increase the structural rigidity of the screw, guide rail and other functional components and the machine tool itself. At this time, the cost of the feed system is high, the structure of the machine tool becomes complicated, and the weight is heavy; the other is from the perspective of servo control. Platform vibration, this solution has limited effects and is not universal; the third is to adopt the mechanical structure design concept of the feed system with dual drive units based on the principle of DCG-Drive at Center of Gravity proposed by Mori Seiki. In Japanese Patent JP9262727, a structure based on a machine tool feed system for a horizontal machining center is described, which uses dual linear motors to drive on both sides of the platform. In Japanese patents US2005031429-A1, US2005032616-A1 and US20060143889-A1, a vertical machining center is described, wherein the Y-axis and Z-axis feed systems adopt the above-mentioned DCG-based double-screw bilateral drive structure. In the above-mentioned feeding system structure using double screws, the drive unit layout and platform structure (double screw drive as an example), the workbench is connected to the base through the guide rails, and the ball screw drive units are arranged on the outside of each guide rail, and the working The center of gravity position W of the table is in the same plane as the thrust point of the double screw (screw axis). The above DCG-based feed system structure can effectively suppress machine tool vibration. When the position W of the center of gravity of the worktable (installed workpiece) changes in the Y-axis direction, the Z-axis moment M of the driving force and external force relative to the center of gravity of the worktable can be compensated by controlling the driving force F _dl and F _dr of the double screw to satisfy the following formula _z .

F _dl (cy _dr )-F _dr y _dr -M _z ＝0

In the formula, y _dr and c are respectively the distance between F _dr and the center of gravity W and c is the distance between the double drive units. When the combined center of gravity position W of the worktable and the workpiece rises in the Z-axis direction, the driving forces F _dl , F _dr and the Y-axis moment M _y of the external force F relative to the center of gravity are in the same direction and cannot be compensated. However, the design idea of the feed system structure based on the DCG principle in the above invention can be used as an important method to solve such problems.

Invention content:

The purpose of the present invention is to provide a feed system composed of multiple drive units with a reasonable structure, which can effectively suppress the vibration of the machine tool caused by the change of the center of gravity position of the table of the feed system.

Technical solution of the present invention is:

A feeding system composed of multiple driving units is characterized in that: it includes a workbench, which is connected to the base body through guide rails, the double drive units are respectively arranged on both sides of the upper part of the workbench, and another drive unit is arranged on the lower part of the workbench.

The workbench is in the shape of a ladder. The double drive units are respectively arranged on the steps on both sides of the upper part of the workbench. The guide rails are arranged on the steps on both sides of the middle part of the workbench. There is at least one other drive unit and it is arranged on the bottom of the workbench.

The double drive unit is a double ball screw, and the other drive unit is a linear motor, and the mover of the linear motor is fixedly connected to the bottom of the workbench, and the stator of the linear motor is fixedly connected to the base. When the position W of the center of gravity of the workbench is changed in the direction of the Y axis, the magnitude and direction of the driving force F _dl and F _dr of the double ball screw and the driving force F _dm of the linear motor satisfy the formula (1) to compensate the driving force and external force The Z-axis external force relative to the center of gravity of the worktable is equivalent to the moment M _z of the center of gravity,

F _dl (cy _dr )-F _dr y _dr -F _dm y _dm -M _z ＝0(1)

In formula (1), y _dr , y _dm and c are respectively the distance between F _dr , F _dm and the center of gravity W and the distance between the double drive units;

When the center of gravity position W of the workbench is raised in the Z-axis direction after the workpiece is installed, the magnitude and direction of the driving force F _dl and F _dr of the double screw and the driving force F _dm of the linear motor satisfy the formula (2), which can compensate the driving force and external force Relative to the center of gravity of the table, the Y-axis external force relative to the center of gravity equivalent moment M _y ,

F _dm z _dm -(F _dl +F _dr )z _dr -M _y ＝0(2)

In formula (2), z _dm and z _dr are the distances between F _dm , F _dr and the center of gravity W, respectively.

The double drive units are double ball screws, and the other drive unit is another double screw drive unit, and the other double screw drive units are symmetrically arranged on both sides of the lower part of the workbench guide rail.

The workbench is rectangular, and the double drive units are respectively arranged on both sides of the upper part of the workbench, and there are two other drive units, which are arranged on both sides of the middle and lower part of the workbench.

The workbench is provided with process holes to reduce the weight of the workbench.

The feed system structure of the present invention realizes that when the position of the center of gravity of the workbench changes arbitrarily in a plane perpendicular to the direction of the driving force, the torque relative to the center of gravity formed by the driving force and external force is compensated, and the mechanical vibration of the feed system is suppressed to the greatest extent; it can improve Feed system acceleration; can improve the surface quality of workpiece processing.

Description of drawings:

The present invention will be further described below in conjunction with drawings and embodiments.

Fig. 1 is a structural diagram of Embodiment 1 of the present invention.

FIG. 2 is a Z-direction view of Embodiment 1. FIG.

FIG. 3 is a Y-direction view of Embodiment 1. FIG.

FIG. 4 is a structural diagram of Embodiment 2.

FIG. 5 is a structural diagram of Embodiment 3. FIG.

Detailed ways:

Example 1:

Fig. 1 is a schematic view in the X direction of a feasible structure of a feed system structure and drive unit layout using double ball screws plus linear motors in the present invention. In the figure, the workbench 14 adopts a ladder-shaped structure. In order to reduce the weight of the workbench, a process hole 15 is opened on it. The workbench 14 is connected to the base body 16 through guide rails 13a and 13b. The double ball screws 11a and 11b are respectively arranged on the workbench. On both sides of the table 14, the mover 12a of the linear motor 12 is fixedly connected to the bottom of the workbench 14, and the stator 12b is fixedly connected to the base 16. The linear motor 12 is not limited to be arranged at the symmetrical center of the bottom of the workbench 14. In the present invention, it is not required that the position of the center of gravity of the worktable 14 is in the same plane as the thrust action points of the double drive units 11a and 11b. The present invention can compensate the external moments of the Y-axis and Z-axis by controlling the magnitude and direction of the driving force of the multiple driving units, so as to ensure that the driving force of the X-axis passes through the center of gravity position W of the worktable 14 to realize DCG driving.

Fig. 2 is a schematic diagram of the Z direction of the above-mentioned structure in the present invention. When the position W of the center of gravity of the worktable 14 (attached workpiece 17) changes in the direction of the Y-axis shown in the figure, the magnitude and direction of the driving forces F _dl and F _dr of the double screw and the driving force F _dm of the linear motor satisfy the formula (2), which can compensate the driving The force and external force relative to the center of gravity of the Z-axis external force relative to the center of gravity equivalent moment M _z .

F _dl (cy _dr )-F _dr y _dr -F _dm y _dm -M _z ＝0(2)

In formula (2), y _dr , y _dm and c are respectively the distance between F _dr , F _dm and the center of gravity W and the distance between the double drive units.

Fig. 3 is a schematic diagram of the Y direction in the above-mentioned structure in the present invention, when the combined center of gravity position W of the workbench 14 and the workpiece 17 is raised in the Z-axis direction, the driving force _Fdl , _Fdr of the double screw and the driving force _Fdm of the linear motor The magnitude and direction of satisfying the formula (3) can compensate the equivalent moment M _y of the Y-axis external force relative to the center of gravity of the drive force and external force relative to the center of gravity of the workbench.

F _dm z _dm -(F _dl +F _dr )z _dr -M _y ＝0(3)

In formula (2), z _dm and z _dr are the distances between F _dm , F _dr and the center of gravity W, respectively.

The drive unit configuration form and platform structure requirements in the multi-drive unit feed system: (a) both sides of the drive unit are of the same type, (b) the bottom drive unit does not have to be arranged symmetrically with respect to the bilateral drive unit and is not limited to one drive unit, (c) the platform The center of gravity does not have to be in the same plane as the bilateral drive unit forces. The drive unit used is not limited to a linear motor or a ball screw.

Example 2:

The structure of the feed system in FIG. 4 is a schematic view in the X-axis direction of a configuration of 4 driving units for the loading turntable 20 . It is used in the case where the turntable restricts the configuration of the third drive unit in FIG. 3 in the Z-axis direction. In the figure, the workbench 21 also adopts a trapezoidal structure, and a process hole 22 is opened on it. The workbench 21 is connected to the base body 23 through the guide rails 19a and 19b. On both sides of the part above the guide rail in the platform 21 , the double drive units 18c and 18d are respectively symmetrically arranged on both sides of the part below the guide rail in the workbench 21 .

Example 3:

The structure of the feed system in FIG. 5 is a schematic view in the X-axis direction of the configuration of 4 driving units for loading the main shaft 28 . This structure is suitable for the case where the spindle restricts the configuration of the third drive unit in FIG. 3 in the direction of the Z axis. In the figure, the workbench 26 adopts a rectangular structure, and a process hole 27 is opened on it. The workbench 26 is connected to the base body 29 through the guide rails 25a and 25b, and the double drive units (take the lead screw as an example) 24a and 24b are symmetrically arranged on the workbench respectively. 26 on both sides of the middle and upper part, and the double drive units 24c and 24d are respectively symmetrical to the two sides of the middle and lower part of the workbench 26.

Claims (2)

1. A feed system composed of multiple driving units, characterized in that: it includes a workbench, the workbench is connected to the substrate through guide rails, the double drive units are respectively arranged on both sides of the upper part of the workbench, and another drive is set at the lower part of the workbench unit; the workbench is in the shape of a ladder, and the double drive units are respectively arranged on the steps on both sides of the upper part of the workbench, the guide rails are set on the steps on both sides of the middle part of the workbench, and there is at least one other drive unit, which is arranged at the bottom of the workbench; The double drive unit is a double ball screw, and the other drive unit is a linear motor, and the mover of the linear motor is fixedly connected to the bottom of the workbench, and the stator of the linear motor is fixedly connected to the base; the center of gravity position W When the direction of the Y axis changes, the size and direction of the driving force F _dl and F _dr of the double ball screw and the driving force F _dm of the linear motor satisfy the formula (1) which can compensate the driving force and external force relative to the center of gravity of the Z-axis external force relative to the center of gravity of the table Equivalent moment M _z , F _dl (cy _dr )-F _dr y _dr -F _dm y _dm -M _z ＝0 (1) In formula (1), y _dr , y _dm and c are respectively the distance between F _dr , F _dm and the center of gravity W and the distance between the double drive units; When the center of gravity position W of the workbench is raised in the Z-axis direction after the workpiece is installed, the magnitude and direction of the driving force F _dl and F _dr of the double screw and the driving force F _dm of the linear motor satisfy the formula (2), which can compensate the driving force and external force Relative to the center of gravity of the table, the Y-axis external force relative to the center of gravity equivalent moment M _y , F _dm z _dm -(F _dl +F _dr )z _dr -M _y ＝0 (2) In formula (2), z _dm and z _dr are the distances between F _dm , F _dr and the center of gravity W, respectively. 2. The feed system composed of multiple drive units according to claim 1, characterized in that: the workbench is provided with process holes for reducing the weight of the workbench. the

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