RU2299797C2 - Metal-cutting working center and six-strut mechanism for it - Google Patents

Abstract

FIELD: metal working processes and equipment, NC-machine tools.

SUBSTANCE: working center includes housing, working table, carrying system made in the form of columns mounted in housing and frame mounted on upper ends of columns, mechanism in the form of six struts of controlled length. First ends of said struts are secured to support being in the form of platform carrying spindle and second ends of said struts are secured to carrying system with the aid of cardan joints. In order to provide possibility for working elongated large-size parts, carrying system is in the form of four columns mounted by pairs at lateral sides of table that may move between them along elongated housing. Said mechanism is in the form of six controlled-length struts. Lower ends of said struts are secured to platform carrying spindle and their mean portions are secured to frame by means of cardan joints. Struts are mounted on frame and on platform in points combined by pairs. Pairs of points form on platform mounting zones in the form of small triangles in plan view and on frame mounting zone in the form of large triangle in plan view.

EFFECT: increased rigidity of positioning, enhanced accuracy of working.

2 cl, 8 dwg

Description

Technical field

The invention relates to metalworking, more specifically, to metal-cutting machines, in particular to structural elements included in the general layout, namely to bed devices and devices carrying working spindles, and can be used in numerically controlled machines designed for complex machining of prismatic and volumetric complex products of aerospace, automotive, shipbuilding and other industries to improve their performance and increase productivity oditelnosti.

The level of technology.

Known devices for moving the executive body, intended for use in metal-cutting machines, including a platform for placing the executive body, six rods pivotally mounted on the platform, each of which is equipped with a drive for its longitudinal movement, the body of which is pivotally mounted on the base. In this case, the rods are installed around the circumference and are installed in pairs of parallel rods. (See, for example, AS USSR No. 1142271, B25J 11/00, 1985; No. 1437211, B25J 9/12, 1987) Such devices do not have sufficient rigidity and do not provide the necessary processing accuracy.

Known six-rod (hexapodic) machine system for placing the tool relative to the workpiece, including a pair of spatially arranged supports made in the form of platforms, respectively, for the tool and part, six rod support elements fixed at one end on one platform and the other end on the other platform while six core support elements are arranged in a circle in successive pairs with a certain intersection of pairs with each other, the device of individual mani ulirovaniya for changing the position of the ends of the rod support elements with respect to each other. (See US patent No. 5354158, B23C 1/06, 1994). The system is used in metal cutting machines to move the tool in three linear and three rotational directions relative to the plane of the workpiece.

The known hexapodal system provides a rigid structure for the tool. However, the circular installation of the rods can provide maintenance of a small area for processing parts, i.e. with its help it is impossible to process overall details. In addition, the system does not fit well with tables, especially movable ones, which also limits the size of the tables for fixing and processing parts.

Known hexapodal machining center containing a fixed frame and a support connected by six racks of adjustable length. The attachment points of the three struts on the support form the first work plane, and the attachment points of the three other struts form the second work plane on the support. The attachment points of the struts on the frame also form three separate work planes. The attachment points of both working planes of the caliper are superimposed in such a way that the lines connecting the attachment points of the superimposed pairs are parallel to each other. This allows for a greater degree of support mobility across all six degrees of freedom. (See US patent No. 6241437, B23C 1/12, 2001)

The frame is triangular in shape, the center is equipped with three columns connecting the bed and the frame, and all racks are attached to the columns and the attachment points of adjacent racks to the columns are located on opposite sides of the column and spaced along its axis, and two racks are made intersecting each other.

The disadvantage of this design is that the hexapod design allows the processing of parts in a limited space, i.e. does not allow the processing of large parts. In addition, the presence of a triangular bed and three columns limit the size of the table, do not allow the processing of long products.

SUMMARY OF THE INVENTION

The objective of the invention is to develop such a metal-cutting hexapodal machining center, which would allow for the integrated processing of large and long parts.

In addition, the hexapod support mechanism must provide high and uniform rigidity of spindle positioning in the entire processing area to ensure high machining accuracy and have a minimum size.

Moreover, the machine should be easy to operate, allow for high-precision and reliable alignment and rigidity assessment.

The task is achieved by the fact that in a metal-cutting hexapod processing center containing a bed, a working table, a supporting system made in the form of columns mounted on a bed, and a frame installed on the upper ends of the columns, a hexapod mechanism made in the form of six racks of adjustable length, fixed at one end on a support made in the form of a platform supporting the spindle, and on the other hand, on a supporting system using universal joints, the supporting system is made of four columns mounted in pairs but on the sides of the table, moving between them on an elongated bed, and the frame is quadrangular and is equipped with additional power elements for fixing brackets carrying hinges connecting racks.

In addition, the hexapod mechanism is made in such a way that the racks and attachment points of the racks on the frame and on the platform are grouped in pairs in such a way that each pair of attachment points forms attachment zones on the platform and frame, forming a small triangle on the platform when viewed in plan (top view) located on one side symmetrically relative to the longitudinal axis of the table and parallel to the transverse axis of the table at a distance from it, and the opposing vertex on the longitudinal axis of the table on the other side of the transverse axis, and on the frame when viewed in plan (top) is large a triangle located on one side symmetrically relative to the longitudinal axis of the table and parallel to the transverse axis of the table at a distance from it, and the opposing vertex on the longitudinal axis of the table on the other side of the transverse axis, while the small and large triangle of the attachment zones are directed with their vertices facing each other, and The racks are mounted as follows: the first pair of racks is mounted on the frame and on the platform in areas spaced relative to the longitudinal axis; the second pair of racks mounted on the frame in areas spaced relative to the longitudinal axis, and on the platform in the area on the longitudinal axis of the table; the third pair of racks is mounted on the frame in the zone on the longitudinal axis, and on the platform in the zones spaced relative to the longitudinal axis, while the first and second pair of racks form rays that diverge upward, and the third pair of racks - rays that converge from bottom to top.

This embodiment of a metal-cutting hexapodal machining center provides the greatest rigidity and accuracy of movement of the platform with the tool throughout the processing zone, which in turn improves the accuracy of processing.

In addition, the center allows complex processing of large and long parts.

Moreover, the machine should be easy to operate, allows for high-precision and reliable adjustment and rigidity assessment, and the hexapod support mechanism has a minimum size.

The list of figures in the drawings.

The invention is illustrated by drawings, in which

Figure 1 - shows a longitudinal section of the center along the X coordinate;

Figure 2 - shows a cross section along the coordinate U (dash-dotted lines show the extreme positions of the working bodies of the center);

Figure 3 - shows a plan view of the center;

Figure 4 - shows a section in the plane of the HOU;

Figa, 5b - shows a longitudinal section through the linear displacement mechanism (MLP) of the rack;

6 is a section along the universal joint and a transverse section along the MLP;

Fig. 7 shows a layout of attachment points of the hinges of the hexapod mechanism on the frame and platform when viewed from the front;

Fig. 8 shows a layout of attachment points of the hinges of the hexapod mechanism on the frame and platform when viewed from above.

The implementation of the invention.

The metal-cutting hexapod machining center contains a bed, a work table, a supporting system made in the form of columns mounted on the bed, and a frame installed on the upper ends of the columns, a hexapod mechanism made in the form of six racks of adjustable length, fixed at one end on a support made in in the form of a platform supporting the spindle, and on the other hand, on the supporting system using universal joints.

The center (Figure 1) constructively consists of a bed 1, five sections of which 2, 3, 4, 5, 6 are interconnected by bolt fastening (not shown in the drawings). Three sections 2, 3, 4 carry guides 7 on them, along which the working table 9 (coordinate X) moves on the roller blocks 8.

The table is moved by means of a ball screw with a rotating nut 10 with a fixed screw 11. The rotation to the nut is transmitted through a gear 12 mounted on the end of the table 9 with an electric motor 13. The power supply to the table feed drive is carried out by a flexible cable chain 14. To protect the guides 7 and the screw from shavings 11 serves as a telescopic protection 15.

The supporting system is made of four columns 16 installed in pairs on the sides of the table on two side beds 5, 6. On the upper planes of the columns 16, a frame 17 is installed.

The frame 17 is made quadrangular and is equipped with additional power elements for fixing brackets carrying hinges connecting racks.

The desktop 9 is made moving between the columns 16 on an elongated bed 2, 3, 4.

Frame 17 is a power structure bearing a hexapod mechanism, which serves to install a platform 38 that carries a spindle with a tool, move it and position it in the necessary position for machining parts.

Hexapod mechanism 60 is made in the form of six racks 61, 62, 63, 64, 65, 66 (see Fig. 8), made with a variable length and hinged by one (lower) ends on the platform 38 with attachment points P1, P2, P3 , P4, P5, P6, and the middle parts on the frame 17 with attachment points P1, P2, P3, P4, P5, P6, respectively. Racks 61, 62, 63, 64, 65, 66 and the mounting points of the racks on the frame and on the platform are grouped in pairs so that each pair of mounting points forms mounting zones on the platform and frame, the dimensions of which are determined by the dimensions of the hinges that secure the stands. The fastening zones of the racks on the platform when viewed in plan (top) form a small triangle located on one side symmetrically relative to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex - on the longitudinal axis of the table on the other side of the transverse axis.

The fastening zones of the racks on the frame when viewed in plan (top) form a large triangle located on one side symmetrically relative to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex - on the longitudinal axis of the table on the other side of the transverse axis. The small and large triangle of the attachment zones are directed with their vertices facing each other. The racks are mounted as follows: the first pair of racks 61 and 62 are mounted on the frame and on the platform in areas spaced relative to the longitudinal axis; the second pair of racks 63, 64 are fixed on the frame in zones spaced relative to the longitudinal axis, and on the platform in the zone on the longitudinal axis of the table; the third pair of struts 65, 66 are mounted on the frame in the zone on the longitudinal axis, and on the platform in the zones spaced relative to the longitudinal axis. In this case, the posts 61, 62 and 63, 64 form rays diverging from the bottom up, and the posts 65, 66 - rays converging from the bottom up. The centers of rotation of the hinges of fastening the racks to the platform are located in the same plane, and the centers of rotation of the hinges of fastening the racks to the frame are spaced apart in height to ensure non-intersection of the racks during the movement of the platform with the tool throughout the part processing zone.

Each of the uprights 60 consists of a linear displacement mechanism (MLP) and a retractable rod 28.

The racks are mounted on the frame using six brackets 18, 44, 45, 46, 47, 48, on which cardan joints 19 are fixed.

The brackets have a "P" shaped design, in the lower part of which there are platches for fixing to the horizontal plane of the frame 17, and the upper plane serves for fixing the cardan joints 19.

The fastening planes of each cardan joint have different angles of inclination relative to the vertical planes passing through the axes I-I and II-II of FIG. 3.

The rotation centers of the cardan joints P1, P2, P3, P4, P5, P6 are located in different planes and have different linear coordinates relative to the axes I-I and II-II of Fig. 7.8.

Each cardan joint is made on roller bearings 20, 21 and has two degrees of freedom. Structurally, it consists of two frames 22 and 23. The frames 22 have the ability to rotate at a certain angle relative to the frames 23, which are mounted on brackets 18, 44, 45, 46, 47, 48. In turn, the frame 24 is secured to the frame 22 through bearings 21 , linear movement mechanism (MLP), which in turn has the ability to rotate at some angle relative to frame 22. Thus, each of the six MLPs has two degrees of freedom.

MLP consists of a housing 24, inside of which there is a ball screw (ball screw) 25, one end of which is secured to the housing 24 through a bearing 26, and the second end is in contact with the extension rod 28 through the bearing 27. The task of the MLP is to move according to the program (extension and sliding) of the rod 28 relative to the housing 24.

MLP works as follows. The rotation from the electric motor 29 through the planetary gearbox 30 and the coupling 31 is transmitted to the ball screw 32. The ball nut housing 33 is fixed to the end of the extension rod 28. When the ball screw 32 rotates, the nut 33 together with the rod 28 performs translational motion. Four rods 34 with Teflon slide pads in contact with the four planes of the rod 28 hold the rod from rotation. The retractable rod 28 is closed by corrugated protection 35 from chips and dirt.

To exclude emergency situations during the movement of the rod 28 and when turning the MLP in the cardan joint 19 limit switches 36 are installed.

At the end of the rod 28, a hinge 37 is fixed, which has three degrees of freedom: rotation around the axis of the rod and two rotations around axes intersecting at right angles, the intersection point of which passes through the axis of the rod.

Six hinges 37 with their mounting planes are mounted on the platform 38.

The fastening planes of each hinge 37, similar to the fastening of the cardan hinges 19, have different angles of inclination relative to the vertical planes passing through the axes I-I and II-II of FIG. 3.

However, the centers of rotation of these hinges P1, P2, P3, P4, P5, P6 are located in the same plane in height, although they have different linear coordinates relative to the axes I-I and II-II of FIG. 8.

An electric spindle 39 with a tool for processing a part is mounted on the platform 38.

Thus, with the simultaneous operation of all six MLPs, the platform moves with the electrospindle both in three linear coordinates O, Y, Z, and in two rotary A and B figures 1, 2, 3.

The signals about the actual movement of the rods 28 come from the feedback sensors 40. Special mathematical software, processing these signals, determines the actual position of the spindle in the Cartesian coordinate system.

The center has a tool magazine 41 for automatic installation and change of tools in the spindle.

The center is controlled by a numerical control device (CNC) 42 based on an industrial computer with the Windows NT 4.0 operating system.

The CNC unit has a special board with a high-speed optical interface (Sercos) for communication with drives and an interface for controlling input / output modules of discrete and analog signals.

It has an expanded set of functions and commands, as well as the ability to integrate user programs written in C ++ (for example, coordinate transformation for non-standard machine kinematics).

The center has two conveyors for harvesting chips 43 located on both sides of the table 9 for installing and securing the part.

The power supply to the center electric spindle is carried out by a flexible cable-carrying chain 44.

The workpiece is installed and fixed on the movable table 9. The working bodies are in the initial positions to start processing in accordance with Figure 1. The control program is entered in the CNC 42 from a magnetic medium (diskette) or in another way. If necessary, its graphical working out is viewed on the CNC screen (without movements of the working bodies in coordinates), it is possible to adjust the program according to the results of graphical working out.

The buttons from the CNC control panel turn on the electric drives, the state of which is automatically tested, at the same time the electric spindle control station, the air-oil lubrication station of the spindle bearings and the electric spindle cooling station are turned on.

After receiving answers about the readiness of these systems, permission is given to exit to the starting positions in the coordinates and start the part processing program. Initial provisions are specific permanent provisions of the working bodies in which they are established before the start of processing and from which the processing program is calculated.

In the mode of initialization, the working bodies are installed in these positions by dashed marks of the optical feedback sensors 40.

After starting the program from the CNC button, the electrospindle goes to the tool change point. The first tool is removed from the magazine 41 and installed in the spindle.

Processing both three-coordinate and five-coordinate is carried out by moving the table with the part (X coordinate) and moving the platform (coordinate U, Z, A, B).

After processing the part with the first tool, the electrospindle goes to the tool change point, the tool is changed in the spindle and the above cycle is repeated.

When installing the probe in the spindle, the center can be used as a measuring machine.

During the tool change, the tool cone and spindle are cleaned, as well as clamp control.

Simultaneously with the beginning of the processing, the conveyors for harvesting chips 43 are switched on.

The center allows you to mill surfaces with face, end and shaped mills, drill holes and bore holes, and also measure parts, conduct complex processing of products with complex spatial shapes of single, double and alternating curvature. Typical workpieces: beams, ribs, spars, panels, master models, forming equipment.

The advantages of the center are:

- simplification of the design due to unification in feed drives (six identical MLPs);

- reduction of metal due to the use of structural elements of parallel kinematics;

- reduction of energy consumption for operation while achieving high dynamic characteristics of the executive bodies of low metal consumption.

Claims (3)

1. Metal-cutting hexapod processing center containing a bed, a work table, a supporting system made in the form of columns mounted on a bed, and a frame installed on the upper ends of the columns, a hexapod mechanism made in the form of six racks of adjustable length, fixed at one end to a support made in the form of a platform supporting the spindle, and on the other hand, on the supporting system using universal joints, characterized in that the supporting system is made of four columns mounted in pairs on each side of the table, moving between them on a frame made elongated, and the frame is quadrangular and is equipped with additional power elements for fixing brackets carrying hinges for mounting the racks. 2. The metal cutting center according to claim 1, characterized in that in the hexapod mechanism, the struts and mounting points of the struts on the frame and on the platform are grouped in pairs, each pair of mounting points forming mounting zones on the platform and frame forming on the platform when viewed in plan or top, a small triangle located on one side symmetrically relative to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex on the longitudinal axis of the table on the other side of the transverse axis, and on the frame when viewed as on the top or bottom, a large triangle located on one side symmetrically with respect to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex - on the longitudinal axis of the table on the other side of the transverse axis, while the small and large triangle of the attachment zones are directed opposite each other, with the first pair of racks mounted on the frame and on the platform in areas spaced relative to the longitudinal axis, the second pair of racks mounted on the frame in areas spaced relative to the longitudinal axis and on the platform - in the zone on the longitudinal axis of the table, the third pair of racks is mounted on the frame in the zone on the longitudinal axis, and on the platform - in zones spaced relative to the longitudinal axis, while the first and second pair of racks form rays diverging from the bottom up, and the third pair of racks - rays converging from the bottom up. 3. Hexapod mechanism for a metal-cutting machining center, made in the form of six racks of variable length, fixed by one lower end on a platform carrying a spindle, and the middle parts on the frame using universal joints, characterized in that the racks and mounting points of the racks on the frame and on the platform are grouped in pairs, with each pair of attachment points forming attachment zones on the platform and frame, forming a small triangle on the platform when viewed from a plan or from above, symmetrically located on one side relative to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex - on the longitudinal axis of the table on the other side of the transverse axis, and on the frame when viewed in plan or from above, a large triangle located on one side symmetrically with respect to the longitudinal axis of the table and parallel to the transverse axis of the table, at a distance from it, and the opposing vertex - on the longitudinal axis of the table on the other side of the transverse axis, while the small and large triangle of the attachment zones are directed vertices in the opposite direction to each other, By the way, the first pair of racks is fixed on the frame and on the platform in the zones spaced relative to the longitudinal axis, the second pair of racks is fixed on the frame in the zones spaced relative to the longitudinal axis, and on the platform in the zone on the longitudinal axis of the table, the third pair of racks is fixed on the frame in zone on the longitudinal axis, and on the platform, in zones spaced relative to the longitudinal axis, the first and second pair of racks form rays diverging from the bottom up, and the third pair of racks form rays converging from the bottom up.

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