RU2542878C2 - Configuration of multi-purpose machine on basis of principles of parallel kinematics - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: machine contains a stand, three racks, a sled mounted with a possibility of movement along vertical guiding racks, a spindle mounted in the housing, three pair of rods in pairs connecting among themselves the housing and the sled by means of hinges, a table for placement of a processed detail. Meanwhile it is fitted with additional pair of rods integrated with one of the mentioned pairs of rods in such a manner that the rods ends facing towards the sled are connected with by a common hinge, and the opposite ends of these rods are connected in pairs to the housing using the hinges located symmetrically with reference to the housing axis. Each pair of rods is located in the vertical plane, and the plane in which bars of additional pair and the bars of the mentioned pair are placed, are located at sharp angle to each other. Besides, the racks at the level of vertical guides along the perimeter are connected to each other with plates.

EFFECT: invention allows to simplify a design and to improve the processing accuracy with simultaneous providing of high dynamic characteristics of the machine.

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Description

The invention relates to machine tool industry and can be used in the design of high-speed multi-purpose machines with high productivity, as well as high dynamic characteristics and low metal consumption.

The well-known multi-purpose machine HEXAMEX-1 (OJSC SAVMA, Savelovo, www.komtech-stanki.ru), including a base, four racks, a frame, six telescopic rods mounted on it connected to a platform (Stuart platform), a motor a spindle mounted on the platform, a table for attaching the workpiece. The disadvantages of this machine are low torsional (angular) rigidity of the platform, as well as insufficient rigidity of the machine as a whole.

Also known is a high-speed multi-purpose machine with a tripod module (patent RU 2285602 C1, B23Q 1/54, 10/20/2006) containing a spindle support with a spindle head, a bed, a support system for installing and moving the spindle support, a table for installing and fixing the workpiece ( details). The spindle caliper is made in the form of a hollow vertical prism mounted by movable supports on rails mounted on a traverse and connected with a transverse drive, each of the three prism faces located at an angle of 120 ° to each other and rigidly interconnected, made in in the form of a flat plate bearing a motion module on the inner surface, the carriage of which is equipped with an eye for a hinged connection of a rod made of a triangular shape in the form of two converging rods and fixed by upper ends on a fork connected by an axis to the eye, and the lower end of the rod by a universal joint is connected to the base of the spindle head so that three rods with motion modules form a tripod module for moving and controlling the position of the base of the spindle head.

The disadvantages of this machine are low torsional (angular) rigidity of the platform, as well as insufficient rigidity of the machine as a whole, high metal consumption.

The closest technical solution chosen as a prototype is a multi-purpose machine (US 6655247 (B1) B23B 3/20, B23Q 1/00, B23Q 1/54, B23Q 11/08, 12/02/2003; machine mod. V100 from INDEX, Germany, http://www.index-werke.de), including a base, three racks, slides mounted with the possibility of controlled linear movement along the vertical rails of the racks, a spindle mounted in the housing, three pairs of rods, pairwise forming parallelograms and connecting between a supporting part of the body and the slide through universal joints. In this case, the centers of the hinges mounted on the supporting part of the housing, and the centers of the hinges of the pair rods mounted on the rails lie in planes perpendicular to the axis of the spindle.

The disadvantages of this multi-purpose machine are the low angular rigidity of the support part of the body (around the vertical axis of the machine and the axis of the spindle, around the horizontal axis crossing the axis of the spindle), as well as insufficient rigidity of the machine as a whole. This is because each of the pairs of rods forms parallelograms lying in planes located at an angle to the horizontal plane, and their hinges mounted on the supporting part of the body lie in the horizontal plane. The presence of a radial component of the cutting, located below this plane, will lead to the occurrence of a tilting moment, which leads to deformation of the entire system of rods, and therefore to a decrease in the accuracy of processing. The presence of torque will also lead to deformation of the entire boom system, as a system of parallelograms arranged in series cannot provide the required stiffness. In addition, the racks experience bending stresses in the slide movement zone, because cutting forces perceived by the spindle are transmitted through the rods to the slide and then to the racks, which leads to their bending, which means a decrease in the rigidity of the machine and loss of precision.

The objective of the invention is to simplify the design, improve the accuracy of processing, ensuring high dynamic characteristics of the movable support part of the housing with a spindle unit.

The task is achieved in that a multi-purpose machine for complex high-speed machining of parts, containing a base, three racks, a slide mounted to move along the vertical rails of the racks, a spindle mounted in the housing, three pairs of rods, pairwise connecting the housing and the slide using universal hinges, forming parallelograms, a table for installing the workpiece. At the same time, each of the pairs of rods is located in a vertical plane, in addition, it contains an additional pair of rods, combined with one of the pairs of rods in such a way that the ends of the rods facing the slide are connected to it by a common universal joint, and the opposite ends of these rods are connected in pairs with the body by hinges symmetrically relative to the axis of the body, forming in the vertical plane two parallelograms located at an acute angle to each other, in addition, the rack, at the level of the vertical guides, along the perimeter py interconnected slats.

Figure 1 presents a section aa in figure 2.

Figure 2 shows a top view of figure 1.

Figure 3 shows a section bB in figure 2.

The machine contains a base 1, racks 2. On the faces of the racks facing the inside of the machine, vertical guides 3 are mounted along which the slide 4 moves (the slide drive is not shown, it can be a screw-nut drive, linear motor, etc.). On the slide 4 mounted two universal joints 5 and 6 with two degrees of freedom and located coaxially in a vertical plane. The spindle 7 is mounted in the housing 8. On the housing 8, in the vertical planes opposite to the two slides 4, the upper 9 and lower 10 hinges are mounted, similar in design and relative orientation to the hinges 5 and 6. The hinges 5, 9 and 6, 10 are connected by rods 11 and 12, forming parallelograms. On the third slide 13, the upper 14 and lower 15 universal joints are made. On the housing 8 symmetrically to the supports 9 and 10, 14 and 15, two pairs of supports 16, 17 and 18, 19 with a horizontal axis of rotation, arranged in pairs coaxially, are made. The hinges 14, 15 are connected by rods 20 and 21 with the hinges 16 and 17, 18 and 19, forming two parallelograms with common horizontal axes. At the level of the guides 3, the racks 2 are interconnected by plates 22. In addition, the machine includes a table (fixed, globe) 23 for installing the workpiece, tool 24. A tool magazine (not shown) can be mounted, for example, in zone “B”.

The work of the machine is as follows.

The workpiece is installed and fixed on the table 23. The working bodies of the machine are in the initial positions to start processing in accordance with figure 1. The control program is entered in the CNC (not shown) and provides coordinated positioning of the slide 4 and 13 in the Z coordinate according to an algorithm that implements a given version of the toolpath 24 in three coordinates (X, Y, Z) relative to the workpiece. Five-coordinate processing is possible when fixing the workpiece to a globe table (not shown), adding two more controllable coordinates.

After processing the part with the first tool, the spindle 7 goes to the tool change point (zone "B"), the tool 24 in the spindle 7 is changed.

When the probe is installed in spindle 7, the center can be used as a measuring machine.

Figure 2 dashed lines show the possible positions of the spindle 7, which determine the size of the working space of the machine.

This layout of the multi-purpose machine eliminates the disadvantages of the prototype. High angular stiffness of the housing (around the vertical axis of the machine and the axis of the spindle) is ensured by the fact that the rods 20 and 21 together with the support 14 and the housing 8 form a triangle, which is a rigid figure, preventing the rotation of the housing 8 around the axis from the acting cutting forces. High rigidity around the horizontal axes intersecting the axis of the spindle 7 is ensured by the fact that each of the pairs of rods 11, 12, 20 and 21 forms parallelograms lying in vertical planes. At the same time, their hinges mounted on the supporting part of the housing 8 lie in horizontal planes that are remote from each other, forming a two-support mounting scheme for the housing 8, in contrast to the prototype, where all the hinges mounted on the housing lie in the same horizontal plane, forming a single-bearing housing mounting scheme. In addition, the racks 2 experience significantly lower bending stresses in the zone of movement of the slide 4 and 13 along the guides 3, because it is in this zone that the plates 22 are connected to each other, forming a triangle and thereby increasing the bending stiffness of the racks 2. These differences provide an increase in the rigidity of the machine as a whole and lead to an increase in machining accuracy and a decrease in its metal consumption. In addition, high dynamic characteristics of the machine are ensured by reducing the mass of the moving spindle unit.

Claims (1)

A multi-purpose machine for complex high-speed machining of parts, containing a base, three racks, a slide mounted to move along the vertical rails of the racks, a spindle mounted in the housing, three pairs of rods arranged in each pair parallel to each other and connecting the housing and the slide through hinges, a table for installing the workpiece, characterized in that it is equipped with an additional pair of rods located parallel to each other, and plates installed around the perimeter between balls at the level of their vertical guides, while each of the pairs of rods is located in the corresponding vertical plane, one of the ends of the rods of the additional pair is connected by common hinges with the corresponding ends of the rods of one of the pairs and with the slide, and the other ends of the rods of the additional pair are connected to the body by means of hinges located relative to the axis of the body pairwise symmetrically arranged on the body of the hinges of the rods of the said pair, with vertical planes in which the rods of the additional pair and angas said pair are arranged at an acute angle to each other.

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