CN100503150C - Five-degree-of-freedom hybrid CNC machine tool - Google Patents

Abstract

A numerally controlled machine-tool with 5-freedom serial-parallel mechanism for machining complex curved workpiece has an upper fixed platform, a lower movable platform, 4 telescopic connecting rods between said fixed and movable platforms, the first servo motor linked with the top ends of said 4 telescopic connecting rods, a connection axle installed to the supporting bottom surface of said movable platform and linked with the second servo motor, an electric mainshaft installed to said connection axle, and cutting tool fixed to lower end of said electric mainshaft.

Description

Five-degree-of-freedom hybrid CNC machine tool

technical field

The invention relates to a five-degree-of-freedom numerical control machine tool, which belongs to the technical field of mechanical manufacturing.

Background technique

In the past ten years, parallel machine tool has been a hot topic in the field of CNC machine tool research at home and abroad. Parallel machine tools, also known as virtual axis machine tools, are knowledge-intensive, intelligence-intensive, and technology-intensive mechatronics high-tech products. Scholars have invested a lot of research work on it (the citation publication number is CN 1788929A, the Chinese invention patent titled "five-axis linkage and series CNC machine tool").

Parallel machine tools have many advantages compared with traditional CNC machine tools. In a traditional machine tool, the feed axis that drives the tool and the workpiece to move relative to each other is arranged according to Cartesian coordinates, and is in a series and open chain structure. In order to realize five-axis machining, it is necessary to add two more axes to the traditional three-axis machine tool to control the attitude of the tool, all of which are arranged in series. When one axis moves, it needs to drive all the following axes on the series kinematic chain to move together, so the motion inertia is large and the dynamic performance is poor. The cutting force produced at the same time is transmitted along the open chain, so that the defects of each component will have an impact on the cutting accuracy. The kinematic platform of the parallel machine tool is driven in parallel by several simple serial kinematic chains. The structure is simple, the system has a large rigidity-to-weight ratio, fast response speed, suitable for high-speed CNC operations, high precision of the mechanical body, and easy reconfigurable and modular design. , high value-added technology (cited "the development status and prospects of parallel machine tools". Chen Wenjia, Wang Hongguang, Fang Lijin, Zhao Mingyang. Mechanical and Electrical Engineering. 2001, 18(4): 5-8).

At present, most of the parallel machine tool products at home and abroad use the general Stewart six-degree-of-freedom parallel robot mechanism to realize five-axis motion, but the structure of these mechanisms is relatively complex, the working space and the volume of the mechanism are relatively small, the operation is complicated, and the cost is high. The drive and transmission of one shaft is wasted and the cost is increased.

Contents of the invention

The purpose of the present invention is to provide a five-degree-of-freedom parallel CNC machine tool, which can solve the problems of complex curved surface parts in the existing six-degree-of-freedom parallel machine tool processing space, complex structure, small volume ratio between the working space and the mechanism, complicated operation, and high cost. The problem.

The present invention includes four first servo motors, a fixed platform and a moving platform; the present invention also includes four telescopic connecting rods, a second servo motor, an electric spindle, a connecting shaft and a tool; the fixed platform is located above the moving platform, and the moving The platform and the fixed platform are connected by four telescopic connecting rods, the upper ends of the four telescopic connecting rods are respectively connected to the first servo motor, and the connecting shaft is installed on the support wall at the lower end of the moving platform, and the connecting shaft is equipped with The electric spindle connected to the motion platform in rotation, the lower end of the electric spindle is fixedly equipped with a tool, the output shaft of the second servo motor is connected to the connecting shaft through transmission; the four telescopic links are composed of the first telescopic link, the second telescopic connecting rod, the third telescopic connecting rod and the fourth telescopic connecting rod; the upper end of the first telescopic connecting rod and the upper end of the second telescopic connecting rod are respectively connected to the fixed platform through the first Hooke hinge, and the first telescopic connecting rod The lower end of a telescopic link and the lower end of the second telescopic link are respectively connected to the motion platform through a ball joint, and the upper end of the third telescopic link and the upper end of the fourth telescopic link are respectively connected to the moving platform through the second Hooke hinge. The fixed platform is connected, and the axes of the first-stage rotating pairs of the two second Hooke hinges coincide with the Y axis; the lower ends of the third telescopic connecting rod and the lower ends of the fourth telescopic connecting rod are respectively connected to the moving platform through the rotating pair, The axes of the two revolving pairs and the axes of the secondary revolving pairs of the two second Hooke hinges are respectively parallel to the X axis.

The present invention has the following beneficial effects: 1. The present invention realizes three-dimensional movement and one-dimensional rotation of the motion platform through the first servo motor driving four telescopic links (that is, the movement of the motion platform along the X, Y, and Z axes and the movement along the X axis respectively). Rotation), while the second servo motor drives the connecting shaft to rotate, so that the tool on the motion platform has three-dimensional spatial movement and two-dimensional rotational movement relative to the workpiece to be processed. Therefore, the hybrid CNC machine tool can completely replace the traditional serial multi-axis machine tool and six-degree-of-freedom parallel machine tool to realize the processing of space complex curved surface parts. 2. Compared with the traditional tandem multi-axis machine tool, the present invention has higher precision and dynamic performance, and is simple in structure, low in cost and easy to manufacture. 3. Compared with the existing six-degree-of-freedom parallel machine tool, the present invention has simple structure, large working space and low cost.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the present invention.

Detailed ways

Embodiment 1: This embodiment is described in conjunction with FIG. 1. This embodiment consists of four first servo motors 1, a fixed platform 2, a moving platform 3, four telescopic connecting rods 4, a second servo motor 5, an electric spindle 6, The connecting shaft 7 and the cutter 8 are composed; the fixed platform 2 is located above the moving platform 3, and the moving platform 3 and the fixed platform 2 are connected by four telescopic connecting rods 4, and the upper ends of the four telescopic connecting rods 4 are respectively connected with the The first servo motor 1 is driven and connected, and the connecting shaft 7 is installed on the support wall at the lower end of the moving platform 3. The connecting shaft 7 is equipped with an electric spindle 6 that is rotatably connected with the moving platform 3, and the lower end of the electric spindle 6 is fixedly equipped with a tool 8. , the output shaft of the second servo motor 5 is in transmission connection with the connecting shaft 7 .

Specific embodiment two: This embodiment is described in conjunction with Fig. 1, the four telescopic links 4 of this embodiment are composed of a first telescopic link 9, a second telescopic link 10, a third telescopic link 11 and a fourth telescopic link 12; the upper end of the first telescopic link 9 and the upper end of the second telescopic link 10 are respectively connected to the fixed platform 2 through the first Hooke hinge 13, the lower end of the first telescopic link 9 and the second The lower ends of the two telescopic connecting rods 10 are respectively connected to the moving platform 3 through a ball joint 14, and the upper ends of the third telescopic connecting rod 11 and the upper end of the fourth telescopic connecting rod 12 are respectively connected to the fixed platform through the second Hooke hinge 15. 2 connection, the first-stage revolving pair axis 16 of the two second Hooke hinges 15 coincides with the Y axis (the establishment of the coordinate system is: the Y-axis coincides with the direction of the first-order revolving pair axis of the two second Hooke hinges 15 , the X-axis is in the plane of the fixed platform 2, and the Z-axis is perpendicular to the X-axis and the Y-axis respectively); 3 connection, the axes of the two revolving pairs 17 and the secondary revolving pair axes 18 of the two second Hooke hinges 15 are respectively parallel to the X axis. Such setting can realize the movement of the motion platform 3 along the X axis, the Y axis and the Z axis and the rotation around the X axis.

Embodiment 3: This embodiment is described with reference to FIG. 1 . The axis of the connecting shaft 7 in this embodiment is perpendicular to the axes of the two rotating pairs 17 and parallel to the plane where the axes of the two rotating pairs 17 are located. With such arrangement, the freedom of the tool to rotate along the axis of the connecting shaft 7 can be realized, thereby ensuring the three-dimensional movement and the two-dimensional rotational movement of the tool relative to the workpiece to be processed.

When the machine tool is working, four telescopic connecting rods 4 are driven by four first servo motors 1 to perform telescopic movement to realize the three-dimensional movement and one-dimensional rotation of the motion platform 3. At the same time, the second servo motor 5 drives the connecting shaft 7 to rotate, so that the tool is relatively The motion platform 3 can realize three-dimensional movement and two-dimensional rotational movement in space, so as to realize the processing of parts with complex curved surfaces in space.

Claims (2)

1. A five-degree-of-freedom hybrid CNC machine tool, which consists of four first servo motors (1), a fixed platform (2) and a motion platform (3); it is characterized in that the machine tool also includes four telescopic links (4), the second servo motor (5), electric spindle (6), connecting shaft (7) and cutter (8); described fixed platform (2) is positioned at the top of motion platform (3), and motion platform (3) It is connected with the fixed platform (2) through four telescopic connecting rods (4), the upper ends of the four telescopic connecting rods (4) are connected to the first servo motor (1) respectively, and the connecting shaft (7) Installed on the support wall at the lower end of the motion platform (3), the connecting shaft (7) is equipped with an electric spindle (6) rotatably connected to the motion platform (3), and the lower end of the electric spindle (6) is fixed with a cutter (8), The output shaft of the second servo motor (5) is connected to the connecting shaft (7) in transmission; the four telescopic connecting rods (4) are composed of the first telescopic connecting rod (9), the second telescopic connecting rod (10), The 3rd telescopic connecting rod (11) and the 4th telescopic connecting rod (12) form; The upper end of described first telescopic connecting rod (9) and the upper end of the second telescopic connecting rod (10) respectively pass through the first Hooke hinge ( 13) Connected with the fixed platform (2), the lower end of the first telescopic link (9) and the lower end of the second telescopic link (10) are respectively connected to the moving platform (3) through a ball joint (14) connected, the upper end of the third telescopic link (11) and the upper end of the fourth telescopic link (12) are respectively connected to the fixed platform (2) through the second Hooke hinge (15), and the two second telescopic links The primary rotating pair axis (16) of the gram hinge (15) coincides with the Y axis; the lower end of the third telescopic connecting rod (11) and the lower end of the fourth telescopic connecting rod (12) pass through the rotating pair (17) and the lower end of the fourth telescopic connecting rod (12) respectively. The motion platform (3) is connected, the axes of the two revolving pairs (17) and the secondary revolving pair axes (18) of the two second Hooke hinges (15) are respectively parallel to the X axis, and the X axis is perpendicular to the Y axis . 2. The five-degree-of-freedom hybrid CNC machine tool according to claim 1, characterized in that the axis of the connecting shaft (7) is perpendicular to the axes of the two rotating pairs (17) and is perpendicular to the axes of the two rotating pairs (17). The axes are parallel to the plane.

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