CN103252683A - Five-freedom-degree parallel-serial numerically-controlled machine tool - Google Patents

Abstract

The invention discloses a five-degree-of-freedom hybrid numerical control machine tool, which includes a column, a bed, a workbench and a processing unit; the processing unit includes a support frame, a moving platform, a first branch chain, a second branch chain, and a third branch chain. The chain and the positioning head, the support frame, the first branch chain, the second branch chain, the third branch chain and the moving platform form a three-degree-of-freedom parallel mechanism, and then a positioning head with two degrees of freedom is connected in series on the moving platform. At the same time, there are five driving devices to drive the processing unit to adjust the attitude of the end, so as to realize five-axis linkage processing. The invention has the advantages of simple structure, large ratio of working space to mechanism volume, high rigidity, high precision and five degrees of freedom, can realize five-axis linkage, is suitable for numerical control processing of complex spatial curved surfaces, and has low cost.

Description

A five-degree-of-freedom hybrid CNC machine tool

technical field

The invention relates to a numerical control machine tool, in particular to a five-degree-of-freedom hybrid numerical control machine tool.

Background technique

In the past ten years, parallel/hybrid CNC machine tools have been a hot topic in the field of CNC machine tool research at home and abroad. Parallel/hybrid machine tools have many advantages compared with traditional CNC machine tools. The traditional machine tool has a series and open-chain structure. In order to realize five-axis machining, two more axes need to be added to the traditional CNC machine tool to control the attitude of the tool or the attitude of the workbench, and these axes are arranged in series. Therefore, in When the five-axis is linked, the motion inertia is large, the rigidity is weak, the dynamic performance is poor, and the cutting precision of the end is low. The parallel machine tool is composed of a dynamic platform, a static platform and several simple series branch chains. The hybrid machine tool is composed of a parallel mechanism and a series positioning head. It has a simple structure, a large ratio of working space to mechanism volume, high rigidity, high precision and flexibility. Good performance, suitable for CNC machining of complex space surfaces.

According to the existing patent documents CN1958229A, CN2476392A, CN1788899A and CN201744858U, the existing parallel machine tool consists of a static platform, a dynamic platform and several telescopic branch chains. A key problem in these patents is that there are too many of them The spherical joint is used improperly, resulting in low rigidity and low precision of the whole machine. The parallel machine tool described in the existing patent document CN101774128A uses many rods and hinges, has a complex structure, low rigidity, and a small working space. The parallel machine tools described in existing patent documents CN201324943Y and CN201833184U use a large number of Hooke hinges, three-degree-of-freedom rotary hinges or spherical hinges, resulting in complex structures and poor rigidity of the whole machine.

According to the existing patent documents GB2173472 (or EP0200369, US4790718), SE8502327 (or US4732525), CN1524662, CN1709657A, CN1439492A, it is known that there is a type of spatial hybrid robot with a positioning head for CNC machining, including several axially extending Long or shortened adjustment device; one end of the adjustment device is connected to the fixed frame through a Hooke hinge, and the other end of the adjustment device is connected to the moving platform through a three-degree-of-freedom hinge, resulting in a lower overall rigidity of the mechanism and lower load The ability is poor; in some patents, the passive branch chain is rigidly connected to the moving platform, and connected to the fixed frame through the Hooke hinge to limit certain degrees of freedom of the positioning head. In this type of robot structure, the passive branch chain not only makes the mechanism complicated, but also has a large number of moving components, which makes it easy to interfere during the movement and reduces the working space.

Contents of the invention

The present invention provides a five-degree-of-freedom hybrid numerical control machine tool for solving the technical problems in the known technology. Improve machining efficiency.

The technical solution adopted by the present invention to solve the technical problems in the known technology is: a five-degree-of-freedom hybrid numerical control machine tool, including a column, a bed, a workbench and a processing unit; the column is vertically fixed on the bed , the workbench is fixedly connected to the bed; the processing unit includes a support frame, a moving platform, a first branch chain, a second branch chain, a third branch chain and a positioning head, and the support frame is vertically rotatably connected to On the bed, it is located on the right side of the column; the first branch chain includes a chain horizontal connection pin, a chain support plate, a chain support and a chain linear drive device. The output end of the branch chain linear drive device is connected to the support plate of the branch chain; the support of the branch chain is connected to the support frame through two horizontal connecting pin shafts of the branch chain perpendicular to them, The rotation axis of the branch chain support is perpendicular to the driving direction of the branch chain linear drive device and the rotation axis of the support frame, and one end of the branch chain supporting plate is connected to the moving platform. The lower side is fixed; the second branch chain includes two branch chain horizontal connection pins, two branch chain support plates, two branch chain supports and two branch chain linear drive devices, and the output ends of the two branch chain linear drive devices It is connected with the two branch chain pallets; the two branch chain supports and the support frame are rotatably connected by two horizontal connection pins of the two branch chains perpendicular to them, and the two branch chain supports The rotation axis is perpendicular to the driving direction of the two branch chain linear drive devices and the rotation axis of the support frame, and one end of the two branch chain supporting plates is hinged to the upper side of the moving platform; the third The branch chain includes a first fork structure, three branch chain connecting pin shafts, three branch chain support plates, three branch chain supports and three branch chain linear drive devices, and the output ends of the three branch chain linear drive devices are connected to the three branch chain linear drive devices. The branch chain supporting plate is connected; the first fork-shaped structure is provided with a fork and a handle, and the fork of the first fork-shaped structure is connected to the three branch chains through two connecting pin shafts of the three branch chains. The chain support is hinged, the handle of the first fork-shaped structure is connected with the left side of the column through a rotating pair, and one end of the three-branched chain supporting plate is connected with the moving platform through a second fork-shaped structure , the second fork-shaped structure is provided with a fork and a handle, the fork of the second fork-shaped structure is connected to the three branch chain pallets through the left end hinge, and the handle of the second fork-shaped structure is connected by The rotating pair is connected to the left side of the moving platform, and the rotation axes of the connecting pin shafts of the three branches and the rotation axes of the left hinge are perpendicular to the driving direction of the linear drive device of the three branches; the positioning head It includes an outer support frame, an inner support frame and an electric spindle. The outer support frame adopts a fork-shaped structure, and the outer support frame is provided with an external hinge of the positioning head connected with the vertical rotation of the moving platform on the outside of the fork-shaped structure. The external hinge of the positioning head is driven by a first servo motor, and the first servo motor is installed on the moving platform; the external support frame is connected to the internal support frame through the internal hinge of the positioning head inside the fork structure, The inner support frame is connected with the second servo motor through a transmission mechanism, and the second servo motor is installed on the outer support frame; the inner hinge of the positioning head The rotation axis of the positioning head is perpendicular to the rotation axis of the external hinge of the positioning head; the electric spindle is vertically installed on the inner support frame.

The linear driving device of the branch chain includes a hollow shaft motor fixed to the support of the branch chain through a flange, a lead screw, a nut, a nut support seat and a linear guide rail; both ends of the lead screw are fixed on Said one-chain supporting plate; said nut is connected with the output end of said hollow shaft motor, said nut is connected to said lead screw by thread, and said nut is connected to said nut support base by a rotating pair , the bottom of the nut support seat is fixedly connected with a slider, and the slider is installed on the linear guide rail adapted to it, and the linear guide rail is fixed on the supporting plate of the chain; the lead screw wears Pass the hollow shaft motor, the branch chain support and the nut support seat.

Ribs are provided on the back of the supporting plate of one chain, so that the cross section of the supporting plate of one chain is T-shaped.

The structures of the two-chain linear drive device and the three-branch linear drive device are the same as the structure of the one-chain linear drive device.

The one-chain linear drive device, the two-branch linear drive device and the three-branch linear drive device are any one of linear motors, hydraulic cylinders and air cylinders.

The advantages and positive effects that the present invention has are:

1) Compared with the tandem machine tool, the structure is simple, the ratio of the working space to the mechanism volume is large, the rigidity is high, the precision is high, the flexibility is good, and it is suitable for CNC machining of complex space surfaces;

2) Since there are only three active branch chains, passive branch chains are reduced, thereby reducing the number of moving components, reducing the complexity of the mechanism, and reducing the cost;

3) Due to the rigid connection between the first branch chain and the moving platform, direct measurement can be realized, so that the whole machine has the characteristics of high precision;

4) With high rigidity, high precision and five degrees of freedom, it can realize five-axis linkage CNC machining.

Description of drawings

Figure 1(a) and Figure 1(b) are schematic structural views of the present invention;

Fig. 2 is a schematic diagram of the structure of the first branch chain of the present invention.

Detailed ways

In order to further understand the invention content, characteristics and effects of the present invention, the following examples are given, and detailed descriptions are as follows in conjunction with the accompanying drawings:

Please refer to Figure 1(a) and Figure 1(b), and the directions below are all based on the directions in Figure 1(a). A five-degree-of-freedom hybrid CNC machine tool, comprising a column 1, a bed 8, a workbench 10 and a processing unit; the column 1 is vertically fixed on the bed 8, and the workbench 10 is fixedly connected to the bed body 8; the processing unit includes a support frame 2, a moving platform 5, a first branch chain 3, a second branch chain 4, a third branch chain 7 and a positioning head 9, and the support frame 2 is vertically rotatably connected to the On the bed 8, it is located on the right side of the column 1. In this embodiment, the support frame 2 is connected to the bed 8 through thrust ball bearings, the support frame 2 has one degree of freedom of rotation, and the rotation axis is perpendicular to the bed 8 .

Please refer to Fig. 2, the first branch chain 3 includes a chain horizontal connecting pin 36, a chain supporting plate 32, a chain support 35 and a linear drive device of a chain, and the linear drive of the branch chain The output end of the device is connected to the supporting plate 32 of the branch chain; the support frame 35 of the branch chain is connected to the support frame 2 through two horizontal connecting pin shafts 36 of the branch chain perpendicular to them, One end of a horizontal connecting pin 36 of a chain is fixedly connected to the support 35 of a chain, and the other end is rotatably connected with the support frame 2 through a bearing. The rotation axis of the branch chain support 35 is perpendicular to the driving direction of the branch chain linear drive device and the rotation axis of the support frame 2, and one end of the branch chain supporting plate 32 is connected to the The lower side of the moving platform 5 is affixed. In this embodiment, the branch chain linear drive device includes a hollow shaft motor 34 fixedly connected to the branch chain support 35, a lead screw 31, a nut 37, a nut support seat 38 and a linear guide rail 33. The two ends of leading screw 31 are all fixed on the described one chain supporting plate 32, and described nut 37 is connected with the output end of described hollow shaft motor 34, and described nut 37 is connected on the described leading screw 31 by screw thread, Described nut 37 is connected on described nut support base 38 by rotating pair, and the bottom of described nut support base 38 is affixed with slide block, and described slide block is installed on the linear guide rail 38 that matches with it, and described linear guide rail 38 is fixed on the branch chain supporting plate 32; the lead screw 31 passes through the hollow shaft motor 34, the branch chain support 35 and the nut support seat 38. The hollow shaft motor 34 drives the nut 37 to rotate, and the nut 37 drives the leading screw 31 to move, and the leading screw 31 drives a chain supporting plate 32 to move, thus realizing the telescopic drive of the first branch chain. In particular, a rib plate is installed on the back side of a chain supporting plate 32 to form a T-shaped supporting plate in cross section. This is because the first branch chain 3 is rigidly connected with the moving platform 5 and bears most of the force and The arrangement of T-shaped pallets is beneficial to improve the rigidity of the whole machine. The second and third branch chains 4 and 7 are mainly used to adjust the attitude of the moving platform, and the bearing force and moment are relatively small, so a supporting plate without ribs can be used.

The structural form of the branch-chain linear drive device is not limited to the above-mentioned structures, and may be any one of linear motors, hydraulic cylinders and air cylinders.

The second branch chain 4 is the same as the first branch chain 3 in that: the second branch chain includes two branch chain horizontal connecting pins, two branch chain supporting plates, two branch chain supports and two branch chains Chain linear drive device, the output ends of the two branch chain linear drive devices are connected to the two branch chain supporting plates; the two branch chain supports and the support frame pass through two of the two branch chains perpendicular to The horizontal connecting pins of the chains are rotatably connected, and the rotation axis of the two branch chain supports is perpendicular to the driving direction of the two branch chain linear drive devices and the rotation axis of the support frame.

The difference between the second branch chain and the first branch chain is that one end of the supporting plate of the two branch chains is hinged to the upper side of the moving platform, and the hinge is a rotation formed by a pin shaft and a bearing. vice.

The third branch chain 7 includes the first fork structure 6, three branch chain connecting pins, three branch chain supporting plates, three branch chain bearings and three branch chain linear drive devices, and the three branch chain linear drive devices The output end is connected with the three branch chain supporting plates; the first fork-shaped structure is provided with a fork and a handle, and the fork of the first fork-shaped structure 6 is connected with the two connecting pin shafts inside it. The support of the three branch chains is hinged, the handle of the first fork structure 6 is connected to the left side of the column 1 through a rotating pair, and one end of the three branch chain supporting plate is connected to the moving platform 5 Connected by a second fork-shaped structure, the second fork-shaped structure is provided with a fork and a handle, the fork of the second fork-shaped structure is connected to the three branch chain pallets through the left end hinge, the second fork The handle of the fork structure is connected with the left side of the moving platform 5 through a rotating pair, and the rotation axis of the three-branch connecting pin shaft and the rotation axis of the left-end hinge are all connected with the three-branch linear drive device. The driving direction is vertical.

A better solution is: the structures of the two-chain linear drive device and the three-branch linear drive device are the same as the structure of the one-chain linear drive device.

The positioning head 9 includes an outer support frame 92, an inner support frame 95 and an electric spindle 94. The outer support frame 92 adopts a fork-shaped structure, and the outer support frame 92 is provided with the movable ring on the outside of its fork-shaped structure. Platform 5 vertically rotates the external hinge of the positioning head connected, and the external hinge of the positioning head is driven by the first servo motor 91, and the first servo motor 91 is installed on the moving platform 5; The inside of the shaped structure is connected to the inner support frame 95 through the internal hinge of the positioning head, the inner support frame 95 is connected to the second servo motor 93 through a transmission mechanism, and the second servo motor 93 is installed on the outer support frame 92 Above; the rotation axis of the internal hinge of the positioning head is perpendicular to the rotation axis of the external hinge of the positioning head; the electric spindle 94 is vertically installed on the internal support frame 95 .

The above-mentioned positioning head 9 has two degrees of freedom of rotation and adopts a modular design. The outer support frame 92 is connected with the moving platform 5 through bearings and driven by the first servo motor 91; Two servo motors 93 and gear transmission are used to control the rotation of the inner support frame 95, and the inner support frame 95 is used for installing the electric spindle 94; the rotation axes of the inner and outer support frames are vertical.

In the processing unit, the support frame 2, the first branch chain 3, the second branch chain 4, the third branch chain 7 and the moving platform 5 form a three-degree-of-freedom parallel mechanism, and then a two-degree-of-freedom positioning mechanism is connected in series on the moving platform 5 Head 9, the machine tool has five driving devices to drive the processing unit to adjust the attitude of the end during processing, so as to realize five-axis linkage processing.

The above descriptions of the present invention and its implementations are schematic and not restrictive. What is shown in the drawings is only one of the implementations of the present invention, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the inventive concept of the present invention, adopt other forms of branch chains, driving devices, hinge connections and positioning heads, without creative design, propose a technical solution similar to the above Similar structural modes and implementation modes shall all belong to the protection scope of the present invention.

Claims (5)

1. a five degree of freedom series-parallel connection Digit Control Machine Tool is characterized in that, comprises column, lathe bed, workbench and machining cell; Described column is vertically fixed on the described lathe bed, and described stationary table is connected on the described lathe bed;

Described machining cell comprises bracing frame, moving platform, first side chain, second side chain, the 3rd side chain and positioning head, and the support frame as described above vertical rotation is connected on the described lathe bed, is positioned at the right side of described column;

Described first side chain comprises that a side chain level connects bearing pin, a side chain supporting plate, a side chain bearing and a side chain linear drive apparatus, and the output of a described side chain linear drive apparatus is connected with a described side chain supporting plate; A described side chain bearing and support frame as described above by with they all vertical two described side chain levels be connected bearing pin and be rotationally connected, the driving direction of the pivot center of a described side chain bearing and a described side chain linear drive apparatus and the pivot center of support frame as described above are all vertical, and an end of a described side chain supporting plate and the downside of described moving platform are affixed;

Described second side chain comprises that two side chain levels connect bearing pin, two side chain supporting plates, two side chain bearings and two side chain linear drive apparatus, and the output of described two side chain linear drive apparatus is connected with described two side chain supporting plates; Described two side chain bearings and support frame as described above by with they all vertical two described two side chain levels be connected bearing pin and be rotationally connected, the driving direction of the pivot center of described two side chain bearings and described two side chain linear drive apparatus and the pivot center of support frame as described above are all vertical, and an end of described two side chain supporting plates and the upside of described moving platform are hinged;

Described the 3rd side chain comprises that first fork configuration, three side chains connect bearing pin, three side chain supporting plates, three side chain bearings and three side chain linear drive apparatus, and the output of described three side chain linear drive apparatus is connected with described three side chain supporting plates; Described first fork configuration is provided with fork and shank, the fork of described first fork configuration portion within it is hinged by two described three side chains connection bearing pins and described three side chain bearings, the shank of described first fork configuration is connected with the revolute pair that passes on left of described column, an end of described three side chain supporting plates is connected by second fork configuration with described moving platform, described second fork configuration is provided with fork and shank, the fork of described second fork configuration is connected with described three side chain supporting plates by the left end hinge, the shank of described second fork configuration is connected with the left side of described moving platform by revolute pair, and all the driving direction with described three side chain linear drive apparatus is vertical with the pivot center of described left end hinge for the pivot center of described three side chains connection bearing pin;

Described positioning head comprises outer support frame, interior support frame and electric main shaft, described outer support frame adopts fork configuration, described outer support frame is provided with the positioning head external hinge that is connected with described moving platform vertical rotation in the outside of fork configuration, described positioning head external hinge is by first driven by servomotor, and described first servomotor is installed on the described moving platform; Described outer support frame the inside of fork configuration by the positioning head internal hinge with described in support frame be connected, described interior support frame is connected by transmission mechanism with second servomotor, described second servomotor is installed on the described outer support frame; The pivot center of described positioning head internal hinge is vertical with the pivot center of described positioning head external hinge; Described electric main shaft is vertically mounted on the described interior support frame.

2. five degree of freedom series-parallel connection Digit Control Machine Tool according to claim 1 is characterized in that, a described side chain linear drive apparatus comprises hollow shaft motor, leading screw, nut, nut support seat and the line slideway affixed with a described side chain bearing;

The two ends of described leading screw all are fixed on the described side chain supporting plate;

Described nut is connected with the output of described hollow shaft motor, described nut is by being threaded on the described leading screw, described nut is connected on the described nut support seat by revolute pair, the bottom of described nut support seat is connected with slide block, described slide block is installed on the described line slideway adaptive with it, and described line slideway is fixed on the described side chain supporting plate;

Described leading screw passes described hollow shaft motor, a described side chain bearing and described nut support seat.

3. five degree of freedom series-parallel connection Digit Control Machine Tool according to claim 1 is characterized in that the back side of a described side chain supporting plate is provided with gusset, makes the cross section of a described side chain supporting plate T-shaped.

4. five degree of freedom series-parallel connection Digit Control Machine Tool according to claim 1 and 2 is characterized in that, all the structure with a described side chain linear drive apparatus is identical for the structure of the structure of described two side chain linear drive apparatus and described three side chain linear drive apparatus.

5. five degree of freedom series-parallel connection Digit Control Machine Tool according to claim 1, it is characterized in that a described side chain linear drive apparatus, described two side chain linear drive apparatus and described three side chain linear drive apparatus are any one in linear electric motors, hydraulic cylinder and the cylinder.

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