RU2605769C1 - Frameless inductance coil manufacturing method and mandrel for production thereof - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering and intended for of frameless inductance coil manufacturing for high-voltage high-frequency voltage transformer and can be used in one-piece design X-ray diagnostic devices with output power of up to 30 kW. Coil lateral cross-section is set number of mandrel detachable segments, each of which on its surface has grooves for wire laying. Wire winding is made by laying of calculated number of turns into each groove, forming winding section by means of section forming device, ensuring clearance between said sections. After last section formation winding leads are soldered on printed circuit board ends fixed on winding surface. Winding is impregnated with dielectric varnish, dried, mandrel is disassembled and finished coil is removed.

EFFECT: technical result consists in reduction of dimensions and parasitic parameters and higher electric strength.

6 cl, 10 dwg

Description

The group of technical solutions relates to electrical engineering and can be used in the manufacture of a frameless inductor for a high-voltage high-frequency voltage transformer. The proposed technical solutions can be implemented, for example, in the designs of monoblock devices of X-ray diagnostic devices with an output power of up to 30 kW.

As you know, the design of the coil depends on the features of the device in which it operates. For monoblock devices of X-ray diagnostic devices, it is important to ensure the minimum overall dimensions of incoming nodes, including a transformer. Minimization of these characteristics allows to reduce the material consumption and cost of the device; at the same time, high electrical strength of the gaps and, consequently, reliability should be ensured.

The transformer increases the high-frequency low-voltage voltage of the supply network to high-voltage, which then goes to the high-voltage rectifier supplying the x-ray tube. To obtain high voltage, high-voltage transformers have low-voltage (primary) and high-voltage (secondary) windings.

A characteristic feature of high voltage transformers is a high transformation ratio. The presence of high voltage windings and at the same time the need to provide the required electric strength creates a number of difficulties when using transformers operating at a high conversion frequency. Reinforced high-voltage insulation and the design of the high-voltage windings of these transformers reduces magnetic coupling and significantly increases the parasitic parameters of the transformer itself (dissipation inductance, interlayer and inter-winding capacity of transformers). The presence of these parameters causes losses in the transformers, distorts the shape of the voltage on the secondary winding of the transformer, and accordingly on the load, and worsens the possibility of using it at high frequency.

The capacitive component of spurious parameters is influenced by the presence of a large number of turns of the secondary winding and the method of winding. With an ordinary multilayer winding, the parasitic capacitance will be determined by the number of layers, the thickness of the interlayer insulation, and the density of the winding. At the same time, in this case, the problem arises of ensuring strength during the transition from layer to layer. Windings in such cases are usually large. Transformers with such windings are laborious to manufacture, technologically sophisticated, and use expensive, inaccessible materials.

The proposed solution relates to a method of manufacturing a frameless inductor, as well as to a mandrel for its manufacture and allows you to create the design of a frameless small coil with minimal spurious parameters and high dielectric strength. The coils, created in accordance with the proposed technical solution, allow you to design a small-sized high-frequency high-voltage transformer for the desired voltage, operating at high frequencies up to 200 kHz.

The prior art method for the manufacture of a frameless coil (RF patent No. 2137279, publ. 09/10/1999), which consists in laying winding coils with the main wire and extreme turns in the rows with a backup wire. For winding coils, a template is used, on the “non-working” side of which, by rotating the template, the main wire of the first row is wound, and then the second row without the last turn of the main winding, observing the checkerboard pattern on the edges and securing its end. Next, by reversing the movement of the template, the backup wire is laid in place of the extreme (last) turn of the second winding row and the formation of the extreme (first) turn of the third row with the chessboard laying of the wire between the second and third row on the working faces of the template. Then the backup wire is fixed on the “non-working” face of the template, thus completing the cycle of forming an odd row and even rows of winding. Then, similarly, the third and fourth (without the end turn) rows of the main winding are formed by the main wire, then by the backup wire the end turns of the fourth (first turn) and fifth (last turn) of the winding row. After winding the required number of rows, the shape of the winding is fixed using a compound and the finished coil is removed from the mandrel. This method is rather laborious, and the coil made in accordance with this method has insufficient strength and stiffness, which affects its electrical characteristics.

There is also known a method according to the patent of the Russian Federation No. 2535838 (publ. 20.12.2014). The method includes winding on the mandrel of the conductor, sequentially winding turns in a predetermined quantity and obtaining from them a predetermined number of rows. For winding the method uses a conductor, which is flattened on the side of the surface of the mandrel, which is wound, as well as on the opposite side. Before winding, an insulating coating is formed on the conductor, after which the first row is wound at a predetermined winding angle, and when passing to each subsequent row of windings, the conductor is deformed in two planes, and in the plane perpendicular to the winding axis, the conductor is bent in the direction from the wound row and in a plane parallel to the axis of the winding, the conductor is bent by an amount providing winding at an angle greater than the angle of winding of the immediately preceding row. This method, despite providing higher quality windings, is technologically complicated due to the many auxiliary operations associated with a preliminary change in the shape of the conductor.

A known method of manufacturing a frameless coil according to the patent of the Russian Federation No. 2340026 (publ. 11/27/2008), which consists in winding a conductive wire into a coil around the outer border of the mandrel, which passes through the center of a pair of guide elements, while a pair of guide elements made in the form of disks, used as guides. A pair of guide elements are spring-loaded towards each other due to the engagement of at least one end of the conductive wire to the outer peripheral parts of the pair of guide elements and the tension of said one end of the conductive wire in the axis direction. After that, the mandrel is separated from the conductive wire wound into a coil, and from a pair of guide elements. This manufacturing method is simpler than the above analogs; a coil made in accordance with it has a higher accuracy of winding, however, this method does not guarantee a coil having a high degree of structural rigidity.

The closest in technical essence to the claimed technical solution is a method of manufacturing a frameless inductor according to the application of the Russian Federation No. 2003138031 (publ. 06/10/2005), which consists in placing the coil winding on a cylindrical mandrel, which is made detachable with two flanges, after receiving its windings are impregnated with dielectric varnish, dried, the mandrel is disassembled and the finished coil is removed. As well as the above-described methods for manufacturing a coil, this method does not provide a sufficiently rigid structure of the resulting coil and the accuracy of winding, and, in addition, using the above methods, it is possible to manufacture a coil of one specific shape.

For the manufacture of coils without a frame, various templates or mandrels are used, the shape of which determines the shape of the coil.

It is known from the prior art, for example, a detachable assembly device (RF patent No. 2340026), essentially a mandrel made in the form of a base containing a protruding part in the form of a disk and a columnar part for winding and having, in addition, guide elements in the form of disks that are spring loaded towards each other by engaging a portion of the conductive wire behind the engaging elements, which are made along the circumference of a pair of guide elements.

For the manufacture of a coil according to the application of the Russian Federation No. 2003138031, the mandrel is made detachable and has a cylindrical rod located between two flanges, one of which is formed by a protrusion on the rod, and the second moving along the rod, with the possibility of fixing the sleeve on it.

The basis of the invention is the task to develop a method of manufacturing a frameless inductor, where through a certain selection of operations and the use of the proposed tools to ensure the technical result: the manufacture of a frameless small coil with the minimum spurious parameters, the smallest possible dimensions and at the same time having high dielectric strength.

The problem is solved in that in the method of manufacturing a frameless inductor, according to which the coil is wound on a mandrel made detachable with two flanges and containing a rod located between these flanges, after receiving the winding it is impregnated with dielectric varnish, dried, the mandrel is disassembled and removed ready the coil according to the invention, before winding the coil, the mandrel bar is made of at least two separate segments, each of which can be cr Insulation to the indicated flanges. On the surface of each segment, transverse grooves are made for laying turns of wire, the number and size of grooves being determined based on a given number of turns and the cross section of the winding wire. Next, the wire is wound by laying in each groove the estimated number of turns, the winding section is formed using the section forming means, which guarantees a gap between the indicated sections. After the formation of the last section, the conclusions of the winding are unsoldered at the ends of the printed circuit board mounted on the surface of the winding, and a winding is obtained.

For the method of manufacturing a frameless inductor, additional options are possible in which:

- the segment is made cylindrical or in the form of a truncated cone, which has a metal core with a fluoroplastic sleeve mounted on it. The segment is fixed between the indicated flanges by means of protrusions located on the opposite end surfaces of the core and in contact with the counter holes of the flanges;

- means for forming each section of the winding is performed in the form of a dividing, for example, mylar, yarn. When laying the windings with the specified thread, all the wires of the section are covered, the thread is pulled, overlapping each section sequentially.

The invention is also based on the task of developing a detachable assembly device — a mandrel, with which it is possible to produce a frameless coil according to the claimed method, and by means of certain design solutions to provide a technical result: the ability to obtain a frameless small-sized inductor having minimal spurious parameters and high electrical strength.

The problem is solved in that in the mandrel for the manufacture of a frameless inductor made detachable with two flanges and containing a rod located between them, according to the invention, the rod contains at least two separate segments, each of which is made with the possibility of fastening to these flanges . The segment has transverse grooves on its surface for laying turns of wire and forming sections of the coil winding using means for forming sections. Each mandrel segment has a locking element, which is a locking pin provided on one of the opposite end surfaces, and the flange has a mounting hole corresponding to the pin. Each flange is made in the form of a plate equipped with slots located along its perimeter to accommodate means for forming the said sections, and the slots are placed regularly with alternation with mounting holes. These slots are made open from the peripheral part of the plate and are limited by fixing screws in its central part, while the screws are placed perpendicular to the outer surface of the plate and are intended for fastening means for forming sections.

Additional mandrel embodiments are possible, in which it is advisable that:

- the segment was made cylindrical or in the form of a truncated cone and was a metal core with a fluoroplastic sleeve mounted on it. In this case, the segment is fixed between the indicated flanges by means of protrusions located on the opposite end surfaces of the core and in contact with the counter holes of the flanges;

- the means for forming sections of the coil winding was made in the form of a dividing, for example, lavsan, thread connected to the springs to hold the corresponding ends of the thread.

Using the proposed group of technical solutions, it is possible to create small-sized coils that do not use frames and which have a rigid structure from sections connected in series with each other with an equal number of turns. The sections are separated by air dielectric gaps, which allow transformer oil to penetrate, providing increased electric strength and normal thermal conditions. The design of the mandrel makes it possible to choose the best option for the geometrical shape of the coil, which has smaller dimensions than the ordinary winding of high-voltage windings, significantly lower spurious parameters, reinforced high-voltage insulation in the absence of additional interlayer tape insulation, and a rigid, lightweight design.

These advantages, as well as features of the present invention are illustrated by drawings, which represent one example of the invention. The essence of the technical solution is shown by the example of manufacturing a frameless inductor obtained by winding on a rod consisting of four segments and having a rectangular cross-section with rounded corners.

In FIG. 1a and 1b show a general view of the mandrel.

In FIG. 2 shows the mandrel segment.

In FIG. 3 shows a side view of the mandrel, from the outside of one of the flanges.

In FIG. 4 shows a view of the mandrel along section AA of FIG. 3.

In FIG. 5 shows a device for rotating the mandrel.

In FIG. 6 shows an inductor manufactured in accordance with the claimed technical solution.

In FIG. 7 shows a view of the inductor from the side of the circuit board.

In FIG. 8 is a vertical section BB of FIG. 7.

In FIG. 9 is an enlarged view of FIG. 8.

In FIG. positions marked:

1 - mandrel segment,

2 - circuit board,

3 - metal core,

4 - fluoroplastic sleeve,

5 - groove,

6 - flange

7 - axial protrusion for mounting segment 1,

8 - a counter hole for the protrusion 7,

9 - locking pin,

10 - mounting hole for the pin 9,

11 - screw

12 - slot

13 - dacron thread,

14 - spring,

15 - output winding

16 - section of the coil.

For the manufacture of a frameless coil, winding in accordance with the proposed technical solution was performed on the device shown in FIG. 5. A mandrel, a general view of which is shown in FIG. 1a and 1b. The mandrel is detachable and for the embodiment described here it contains four cylindrical segments 1, a general view of which is shown in FIG. 2. Each segment 1 can be made in the form of a metal core 3 with a fluoroplastic sleeve 4 mounted on it. On the surface of the fluoroplastic sleeve 4, parallel transverse grooves 5 are made for laying turns of wire and forming section 16 in each groove. Segments 1 are placed between two flanges 6 and each is fixed between the indicated flanges by means of axial protrusions 7 located on the opposite end surfaces of the core 3 and in contact with the mating holes 8 of the flanges 6. Each segment 1 at one end s surface has fixing element representing the locking pin 9 which is placed in the corresponding pin insertion hole 10, preventing thereby the rotation of the segment when winding wire. Each flange 6 is made in the form of a plate equipped with slots 12 located along its perimeter, which are open from the peripheral part of the plate and bounded by fixing screws 11 in its central part, with slots 12 placed regularly alternating with installation holes 10. Slots 12 are designed to accommodate in them mylar thread 13 with the fastening of the ends of the last springs 14.

In FIG. 6-7 show the coil obtained using the proposed method on the mandrel of the proposed design, and in FIG. 8-9 are cross-sectional views of a coil giving an idea of the internal structure of the coil. The coil (Fig. 6) is obtained from a flexible electric wire of circular cross section, coming from a bobbin (not shown in the drawings) through an elastic wick (not shown in the drawings), constantly wetted by an electrical insulating varnish, which allows, after polymerization of the varnish, additional insulation of the turns of each sections 16 and the rigidity of the coil as a whole. The number and size of grooves 5 for forming sections 16 is determined based on a given number of turns and wire cross-section. The number of turns in each groove is determined based on the calculated voltage value. The winding of the coil is as follows. Before laying the wire in the groove 5, the thread 13 is fixed in the springs 14. After winding up the first groove 5 with a predetermined number of turns of wire, the winding is fixed with the thread 13, forming section 16, for which use, for example, polyester thread, which is twisted around wire winding groove. Section fixing is performed on each side of the winding. The wire is transferred to the next groove and all subsequent sections are similarly formed. In FIG. Figure 8 shows that the weaving process occurs along two "mirror" sinusoids. After the formation of the last section, the findings 15 are soldered at the ends of the circuit board 2, mounted on the surface of the winding, impregnated with an electrically insulating varnish, dried, the mandrel is disassembled and the finished coil is removed.

The coil made according to this method using the inventive mandrel design, according to the described example, had a rectangular shape with rounded corners having a bending radius determined by the radius of the segment. This design eliminates the bending of the wire when laying, which is an important factor in the manufacture of the coil.

Thus, the proposed group of technical solutions will provide, firstly, an increase in electric strength while minimizing coil sizes, and secondly, an increase in the manufacturability of coils due to the construction of the mandrel, in particular, the mandrel in the form of segments having grooves for accommodating the wire, allowing to perform an ordered and uniform laying of wires in each groove, and thirdly, simplifying the method of manufacturing a coil using the proposed mandrel. In addition, when using the mandrel of the proposed design, it was possible to manufacture coils having different cross-sectional shapes (for example, rectangular, triangular, square, etc.).

The proposed solution allows using the design of the mandrel using the proposed method to obtain a frameless small coil with minimal spurious parameters, the smallest possible dimensions and having high electric strength. The coil obtained in this way allows you to design a small-sized high-frequency high-voltage transformer for the desired voltage, operating at high frequencies up to 200 kHz.

Claims (6)

1. A method of manufacturing a frameless inductor, according to which the coil is wound on a mandrel made detachable with two flanges and containing a rod located between these flanges, after receiving the winding it is impregnated with dielectric varnish, dried, the mandrel is disassembled and the finished coil is removed, characterized in that that before winding the coil, the mandrel bar is made of at least two separate segments, each of which can be attached to the indicated flanges, on the surface Each segment has transverse grooves for laying turns of wire, the number and size of grooves being determined based on a given number of turns and section of a winding wire; then the winding of the wire is carried out by laying the estimated number of turns in each groove, the winding section is formed using the means of forming a section that guarantees a gap between the indicated sections, after the last section is formed, the winding leads are soldered to the ends of the printed circuit board fixed to the surface of the winding, and a winding is obtained. 2. The method according to p. 1, characterized in that the segment is cylindrical or in the form of a truncated cone, which has a metal core with a fluoroplastic sleeve mounted on it, and is fixed between these flanges by means of protrusions located on the opposite end surfaces of the core and in contact with mating flange holes. 3. The method according to p. 1, characterized in that the means for forming each section of the winding is performed in the form of a dividing, for example, lavsan, thread, while laying the winding with the specified thread, cover all the wires of the section, then the thread is pulled, overlapping each section sequentially. 4. A mandrel for the manufacture of a frameless inductor made detachable with two flanges and containing a rod located between them, characterized in that the rod contains at least two separate segments, each of which is made with the possibility of fastening to these flanges and has on its surface transverse grooves for laying turns of wire and forming sections of the coil winding using means for forming sections; each mandrel segment has a locking element, which is a locking pin mounted on one of the opposite end surfaces, and the flange has a mounting hole corresponding to the pin; each flange is made in the form of a plate equipped with slots located along its perimeter to accommodate means for forming the said sections, and the slots are placed regularly with alternation with mounting holes, made open from the peripheral part of the plate and bounded by fixing screws in its central part, while the screws are placed perpendicular to the outer surface of the plate and are intended for fastening these funds. 5. The mandrel according to claim 4, characterized in that the segment is cylindrical or in the form of a truncated cone and represents a metal core with a fluoroplastic sleeve mounted on it, while the segment is fixed between these flanges by means of protrusions located on the opposite end surfaces of the core and in contact with the counter holes of the flanges. 6. The mandrel according to claim 4, characterized in that the means for forming sections of the coil winding is made in the form of a dividing, for example, lavsan, thread connected to springs to hold the corresponding ends of the thread.

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