TECHNICAL FIELD OF THE INVENTION

The invention relates to a device for two-side varnish stripping from the surfaces of rectangular copper wire, designed for the formation of open type “hairpins” used in the production of rotors and stators for DC electric machines.

PRIOR ART

A device for two-side varnish stripping of a rectangular copper wire [1] is known, which includes a unit for stripping the varnish from the surfaces of a rectangular conductor, connected to a unit for vertically adjusting the stripping unit relative to the size of the rectangular conductor, as well as to a unit for horizontal moving of the stripping unit, all enclosed in a housing. The unit for stripping the varnish from the surfaces of a rectangular copper wire includes two spaced apart pairs, each consisting of a cylindrical stripping diamond disk, against which a clamping disk is disposed on the other side of the rectangular wire. The second pair is spaced apart from the first one and also consists of a cylindrical stripping diamond disk and a clamping disk but disposed contrariwise in relation to the first pair. The unit for the horizontal movement of the stripping pairs consists of guides along which the stripping pairs move along the wire.

A disadvantage of the known device for two-side varnish stripping from the surfaces of rectangular copper wire is that since the stripping is longitudinal along the rectangular wire, in order to be able to strip the varnish not only from the sides of the conductor but also from the adjacent edges, it is necessary to remove a considerable part of the cross-section of the rectangular conductor, which in most cases is unacceptable, for example in the open type harpins. Another disadvantage of the known rectangular copper wire two-side varnish stripping device is that the surface of the diamond-coated cylindrical stripping disks gets smeared with debris from the varnish coating removed from the conductor, which results in poor quality of the stripping process. SUMMERY OF THE INVENTION

The task of the invention is to create a device for two-side varnish stripping from the surfaces of rectangular copper wire which ensures control over the thickness of the material removed from the surfaces of the conductor, with improved quality of the varnish stripping process.

This task is being solved by The device for two-side varnish stripping from the surfaces of rectangular copper wire incorporates, comprising put in a housing, a unit for stripping the varnish from the surface of rectangular copper wire, connected to a unit for vertical adjustment of the stripping unit relative to the size of the rectangular wire, as well as to a unit for horizontal movement of the varnish stripping unit, wherein the unit for varnish stripping from the surfaces of rectangular copper wire comprises two spaced apart pairs of opposite cylindrical elements, each of which includes a stripping cylindrical element.

The unit for varnish stripping from the surfaces of rectangular copper wire comprises movable and fixed plates, in which are formed located each other central pass-through cut-outs, and two pairs of identical spindles being arranged next to each other on one end of the movable plate. Each pair of spindles is fixed a corresponding pair of opposite stripping cylindrical elements. The stripping cylindrical element of each pair of opposite cylindrical stripping elements of the unit for varnish stripping from the surfaces of rectangular wire has been realized as a bottom steel wire brush. The other element of the pair has been realized as an identical to the bottom steel wire brush top steel wire brush. The wire brushes are able to rotate with the same peripheral speed, and the outer diameters of each pair of opposite brushes being spaced apart at a distance corresponding to the thickness of the wire. The respective spindles mounted onto the movable plate, and on its other side, corresponding belts pulleys (9) are fixed, which are connected to an electric motor by means of a belt drive fixed to the fixed plate. The belt drive includes seven parasitic belt pulleys. Four parasitic belt pulleys (are fixed to the movable plate and the remaining three parasitic belt pulleys are fixed to the fixed plate, providing the possibility of opposite rotation of each two homonymous brushes of the pairs of stripping brushes. The cut-out in the movable plate is formed in the horizontal part of the cross-shaped plate connected to it, as the length of this determines the maximum longitudinal travel of the movable plate, respectively, of the pairs of brushes and in the notch in the cross-shaped plate there is a guide supporting the wire in the transverse direction. The unit for the vertical adjustment of the stripping unit relative to the size of the rectangular wire includes two opposite and vertically movable T-shaped plates, each of which slides along a linear guide element. The two T-shaped plates being connected by a screw and two nuts with left and right threads; the unit for horizontal movement of the of the varnish stripping unit consists of linear guides connected to the fixed plate to which a two-position pneumatic cylinder is fixed, the latter being connected by its piston to the movable plate, providing the possibility for the transverse movement of the movable plate together with the brushes across the enamelled wire. After the first module for two-side varnish stripping from the surfaces of enamelled rectangular copper wire is installed a second module for two-side varnish stripping from the surfaces of enamelled rectangular copper wire, which is analogous to the first one and is located from if at a distance which is a multiple of the developed length of the hairpin and, is rotated at 90 degrees with respect to the first module; the first and second modules for two-side varnish stripping are fixedly connected to each other by means of a frame consisting of two plates connected by two columns.

An advantage of the device for two-side varnish from the surfaces of rectangular copper wire, as per the utility model, is that it ensures control over the thickness of the material removed from the surfaces of the wire, with improved vanish stripping quality.

The opposite direction rotation of the two brushes positioned on one side of the conductor allows stripping of the varnish not only from the conductor’s surfaces, but also from the adjacent edges. The ability to vertically adjust the distance between the pairs of opposite steel wire top and bottom brushes allows for a precise control over the thickness of the material removed from the wire’s surface. This adjustment provides control over the pressure between the wire’s surface and the opposite steel wire brushes, which extends the life-span of the brushes. Furthermore, by periodically changing the direction of rotation of the brushes, a self- sharpening effect of the tips of the wires of these brushes is obtained. In addition, the presence of two pairs of opposite steel wire brushes allows decreasing twofold the varnish stripping time. Another advantage is that the required length of the varnish-stripped surface of the wire is achieved by grouping several pairs of opposite steel wire brushes whose combined width corresponds to the desired stripping length. This can also be achieved by consecutive longitudinal movement of the wire in steps equal to or less than the combined width of the pairs of opposite steel wire brushes.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of a device for two-side varnish stripping on rectangular copper wire is shown in the enclosed figures, where: Figure 1 shows a schematic drawing of the belt drive, which moves the pairs of opposite steel wire brushes of the first stripping module,

Figure 2 shows a three-dimensional image of the first and second stripping modules of the device for two-side varnish stripping from rectangular copper wire.

Figure 3 shows a schematic drawing of the elements of the first stripping module providing the vertical adjustment of the pair of opposite steel wire top and bottom brushes.

DETAILED DESCRIPTION OF EMBODIMENT OF THE INVENTION

The varnish stripping device, as per figure 1, includes a first module for two-side varnish removal from enamelled copper wire 1 with a rectangular cross-section, passing through opposite central pass-through notches, cut respectively in the movable 2 and fixed 3 plates. Two pairs of identical spindles 6 are located onto one end of the movable plate 2. As per figure 2, to each pair of spindles 6 is fixed a corresponding pair of opposite steel wire top 4 and bottom 5 brushes of the same diameter, which are capable of rotating at the same peripheral speed. The outer diameters of each pair opposite brushes 4 and 5 are spaced at a distance corresponding to the thickness of the wire 1. As per figure 3, the spindles 6 are connected to two opposite and vertically movable T- shaped plates 7, each of which contacts with a linear guide element 8. Opposite of the pairs of opposite steel wire brushes 4 and 5, on the other side of the movable plate 2, onto the spindles 6 are fixed corresponding belt pulleys 9, which are connected by means of a belt drive 10 to an electric motor 11, fixed to the fixed plate 3. The belt drive 10 also includes seven parasitic belt pulleys. Four parasitic pulleys 12 are connected to the movable plate 2, and the other three parasitic pulleys 13 are connected to the fixed plate 3, providing the possibility of opposite rotation of each two homonymous brushes 4 and 5 within the pair of stripping brushes 4 and 5. The movable plate 2 together with the fixed to it spindles 6 is able to move transversely to the wire 1 through linear guides 14 connected to the fixed plate 3. A two-position pneumatic cylinder 15 is fixed to the fixed plate 3 and is connected to the movable plate 2 by its piston, thus providing a movement of the movable plate 2 together with the brushes 4 and 5 transverse to the enamelled conductor 1. The cut-out in the movable plate 2 is formed in the horizontal portion of a cross-shaped plate 16, connected to it. The length of this cut-out determines the maximum longitudinal travel of the movable plate 2, respectively, of the pairs of stripping brushes 4 and 5. The transverse movement and the locking of the two pairs of stripping brushes 4 and 5 is realized by means of a screw 17 and two nuts with left and right thread connecting the two T-shaped plates 7. Through the cut-out of the movable plate 2 passes a tube guide 18 which supports the wire 1 in transverse direction to prevent it from twisting, due to the peripheral forces arising during its contact with the stripping brushes 4 and 5.

In order to strip the varnish from the other two opposite sides of the wire 1, a second module 19 for two-side varnish stripping from the surfaces of rectangular enamelled copper wire is mounted, which is shown in Fig. 2. The second varnish stripping module 19 is analogous to the first one; it is located next to it at a distance which is a multiple of the developed length of the hairpin and is rotated at 90 degrees relative to the first module. The first and second varnish stripping modules are fixedly connected to each other by means of a frame 20, consisting of two plates 21 fastened together by two columns 22.

USE OF THE INVENTION

The first varnish stripping module of the device for two-side varnish stripping from the surfaces of enamelled rectangular copper wire 1 operates in the following way:

The electric motor 11 drives the belt drive 10 which provides the opposite direction rotation of each two homonymous and unilaterally arranged with respect to the wire 1 stripping brushes 4 and 5. The two-position pneumatic cylinder 15 moves the movable plate 2 together with the pairs of stripping brushes transversely to the enamelled wire 1. The spindles 6 have been pre-set at a distance corresponding to the wire thickness by means of vertically adjustable movement of the T-shaped plates 7 along the linear guide elements 8.

The two pairs of stripping brushes 4 and 5 are continuously rotating at the same peripheral speed and are initially positioned laterally to the wire 1. Upon receiving a signal, the two- position cylinder 15 moves the movable plate 2 together with the fixed to it pairs of opposite stripping brushes until they pass to the other side after the wire 1. This enables the vertical adjustment between the stripping brushes 4 and 5, which controls the thickness of the wire 1 and the varnish coating removed from its surface. The first pair of brushes 4 and 5 rotates against the edges of the wire 1; when they reach the wire 1 they strip these edges and the two adjacent surfaces of the wire 1. The second pair of brushes 4 and 5, which rotates in the opposite direction to the first pair, bypasses these edges without stripping them; they strip again the two adjacent surfaces and the opposite edges of the wire 1.

The required varnish stripped length off the surface of the wire 1 is reached, for example, by grouping several pairs of opposite steel wire brushes 4 and 5, whose total width corresponds to the desired stripped length. This can also be achieved by a consecutive longitudinal movement of the wire 1 by a step equal to or less than the total width of the pairs of opposite steel wire brushes 4 and 5.

The second module 19 for two-side varnish stripping from the surfaces of rectangular enamelled copper wire operates in the same way as the first one and, strips the varnish from the other two sides of the rectangular wire 1.

CITED DOCUMENTS

1. US 7,480,987 B1