CN112071584B

CN112071584B - Multi-voltage output transformer

Info

Publication number: CN112071584B
Application number: CN202010795290.9A
Authority: CN
Inventors: 葛玉华; 张守国; 许唯; 江航龙
Original assignee: Jiangsu Hasen Electric Co ltd
Current assignee: Jiangsu Hasen Electric Co ltd
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2022-06-17
Anticipated expiration: 2040-08-10
Also published as: CN112071584A

Abstract

The invention relates to a multi-voltage output transformer, which comprises a primary coil, a secondary coil, an iron core and a shell, wherein the iron core comprises a movable iron core and a plurality of fixed iron cores, the fixed iron cores are arranged around the movable iron core, the movable iron core is rotationally connected into the shell, a rotating device is arranged on the shell, the rotating device is connected onto the movable iron core to drive the movable iron core to rotate, the movable iron core is C-shaped, and the rotation of the movable iron core can be contacted with the upper end and the lower end of the fixed iron core to form a closed magnetic path; the primary coil is wound on the movable iron core, and the secondary coil is wound on the fixed iron core; taps of the primary coil and the secondary coil both extend out of the housing. The device creatively uses the secondary coils which are annularly arranged, so that the structure is more compact, and more various voltages can be output; the application efficiency of the magnetic flux is improved, and therefore the conversion efficiency of the transformer is improved.

Description

Multi-voltage output transformer

Technical Field

The invention relates to the field of transformers, in particular to a multi-voltage output transformer.

Background

The transformer is a device for changing alternating voltage by using the principle of electromagnetic induction, main components are a primary coil, a secondary coil and an iron core, and in order to adapt to more applicable occasions, namely the function of multi-voltage output, the transformer is realized by adopting one primary coil corresponding to a plurality of secondary coils.

Secondary coils in the existing multi-voltage output transformer are mostly arranged side by side, namely, iron cores are generally in a shape of Chinese character ri, the iron cores wound by the secondary coils are always in a magnetic state, taps of the secondary coils are still unsafe only by the limitation of switches such as circuit breakers and the like, and a closed loop is easily formed due to aging or manual operation errors to cause safety accidents; and under this kind of scheme multivoltage output transformer usually the volume is great, can not set up more secondary coil moreover, too much secondary coil not only makes the transformer volume too huge, and the iron core of a plurality of secondary coils can share the magnetic flux moreover, greatly reduced the conversion efficiency of transformer.

Therefore, a new multi-voltage output transformer is needed, which is not only safe to use, has a large number of output voltage types, but also has high conversion efficiency.

Disclosure of Invention

One object of the present invention is to solve the problems of unsafe use, few kinds of output voltages, and low conversion efficiency of the existing multi-voltage output transformer.

According to one aspect of the invention, a multi-voltage output transformer is provided, which comprises a primary coil, a secondary coil, an iron core and a shell, wherein the iron core comprises a movable iron core and a plurality of fixed iron cores, the fixed iron cores are arranged around the movable iron core, the movable iron core is rotationally connected into the shell, a rotating device is arranged on the shell, the rotating device is connected to the movable iron core to drive the movable iron core to rotate, the movable iron core is in a shape of 'C', and the rotation of the movable iron core can be in contact with the upper end and the lower end of the fixed iron core to form a closed magnetic flux path; the primary coil is wound on the movable iron core, and the secondary coil is wound on the fixed iron core; taps of the primary coil and the secondary coil both extend out of the housing.

According to the scheme, the secondary coils wound on different fixed iron cores have different turns, the movable iron core is rotated to be contacted with the different fixed iron cores to form a closed magnetic circuit, and after alternating current is introduced into the primary coil, the corresponding secondary coil can generate induced electromotive force, so that corresponding voltage is generated; the device creatively uses the secondary coil which is annularly arranged, so that the structure is more compact, and the volume of the transformer is reduced; and the secondary coil can be accommodated in the same or smaller volume, so that more voltages can be output; the secondary coil which is not needed to be used improves the application efficiency of magnetic flux because the fixed iron core cannot be contacted with the movable iron core to form a magnetic path, thereby improving the conversion efficiency of the transformer.

Preferably, the housing is cylindrical, the fixed iron core is radially and slidably connected to the housing, and a pressing device is arranged on the inner wall of the housing and always applies a force towards the movable iron core to the fixed iron core.

Through this scheme, closing device can compress tightly on the iron core moves the iron core with deciding the iron core, makes the contact of the two inseparabler, improves the integrality in magnetic path, reduces the loss of magnetic flux to improve conversion efficiency.

Preferably, the pressing device comprises a spring and an insulating pad, the insulating pad is fixed on the fixed iron core, and the spring is pressed between the insulating pad and the inner wall of the shell; the upper end and the lower end of the fixed iron core are both pressed with the pressing devices.

Through the scheme, the arrangement of the insulating pad can reduce the influence of the magnetic flux on the spring; the fixed iron core can be ensured to be always in an insulation state in the shell; two closing devices compress tightly decide the upper and lower both ends of iron core, guarantee to decide the stability when iron core removes.

Preferably, the movable iron core is sleeved with a sliding sleeve, the sliding sleeve is of a cylindrical structure, an opening is formed in one side of the sliding sleeve, the end portion of the movable iron core is exposed out of the sliding sleeve through the opening, and the fixed iron core is pushed by the pressing device to abut against the sliding sleeve.

Through the scheme, the end part of the movable iron core is exposed out of the sliding sleeve, so that the movable iron core can be in contact with the fixed iron core to form a magnetic path; when moving the iron core and rotating, the sliding sleeve rotates thereupon, makes the fixed iron core can slide along the periphery of sliding sleeve, has improved the stability when moving the iron core and rotating, has realized the smooth-going switching between the fixed iron core.

Preferably, the fixed iron core is C-shaped, both ends of the fixed iron core are arc-shaped concave surfaces, and the radian of the end surface of the fixed iron core is consistent with that of the outer surface of the sliding sleeve; the end face of the movable iron core is an arc convex face matched with the end face of the fixed iron core.

Through the scheme, the contact area between the fixed iron core and the sliding sleeve can be increased, so that the pressure intensity per unit area is reduced, the abrasion between the fixed iron core and the sliding sleeve is reduced, and the service life of the device is prolonged; the arrangement can also play a role in limiting the position between the fixed iron core and the movable iron core, so that the movable iron core can be accurately clamped into the concave surface of the fixed iron core and keeps close fit.

Preferably, the upper end and the lower end of the inner side of the shell are both provided with an insulating strip, the insulating strip is provided with a guide groove, and the upper end and the lower end of the fixed iron core are inserted into the guide groove and extend to slide along the guide groove.

Through this scheme, the guide way can play the guide effect to the removal of deciding the iron core, guarantees that the tip of deciding the iron core can be accurate and move the iron core and contact, stability and reliability when improving this device and using.

Preferably, extend in the guide way the gliding direction of fixed iron core is provided with a plurality of protruding strips, protruding strip set up in on the both sides wall of guide way and the tank bottom surface.

Through this scheme, the area of contact between guide way and the fixed iron core can be dwindled in the setting of protruding strip, reduces the frictional force influence because of unevenness's contact surface causes, improves the guide effect.

Preferably, the casing bottom is provided with the wiring base, it is provided with a plurality of binding post around the casing on the wiring base, primary coil and the tap of secondary coil is connected to respectively on the binding post.

Through this scheme, the wiring base can conveniently take a percentage with the play line tap of secondary coil to fix the inlet wire of primary coil to make things convenient for external consumer and power cord.

Preferably, the periphery of the shell is provided with a plurality of wiring cavities perpendicular to the wiring base, taps of the secondary coils are connected to the wiring terminal through the wiring cavities, and sealing blocks are arranged at openings where the wiring cavities are communicated with the inner cavity of the shell and the outside.

Through this scheme, walk the setting in line chamber and can conveniently reserve certain length to taking a percentage of secondary coil, make secondary coil can remove certain distance along with the fixed iron core, avoid secondary coil frequently to drag the fracture of taking a percentage that causes, reliability when improving this device and using.

Preferably, the upper end and the lower end of the sliding sleeve wrap the movable iron core, the upper end and the lower end of the sliding sleeve are rotatably connected to the shell, and the rotating device penetrates through the shell and is connected to the sliding sleeve; the wire storage cavity is formed in the bottom of the sliding sleeve and is coaxially arranged with the sliding sleeve, and a tap of the primary coil is coiled in the wire storage cavity for at least one circle and then is connected to a corresponding wiring terminal through a wiring groove in the wiring base.

Through this scheme, coil around the circuit of round or above in the storage wire chamber and can make things convenient for primary coil follow-up iron core to rotate, avoid turned angle too big and to the damage of dragging that leads to the fact of taking a percentage, reliability when further improving this device and using.

One technical effect of the invention is that the device creatively uses the secondary coil which is annularly arranged, so that the structure is more compact, and the volume of the transformer is reduced;

the secondary coil can be accommodated in the same or smaller volume, so that more kinds of voltage can be output;

the secondary coil which is not needed to be used can not be contacted with the movable iron core to form a magnetic path, so that the application efficiency of magnetic flux is improved, and the conversion efficiency of the transformer is improved.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic structural view of a multi-voltage output transformer of an embodiment of the present invention.

Fig. 2 is a schematic sectional view taken along the line a-a in fig. 1.

Fig. 3 is a schematic sectional view taken along the direction B-B in fig. 1.

Fig. 4 is a schematic cross-sectional structure of the insulating strip of fig. 3.

Fig. 5 is a schematic view of the structure at C in fig. 1.

Fig. 6 is a schematic view of a contact position structure of a fixed core and a movable core in the multi-voltage output transformer of fig. 1.

Fig. 7 is a schematic cross-sectional view taken along line D-D in fig. 6.

Fig. 8 is a schematic top view of a wiring base in the multi-voltage output transformer of fig. 1.

Fig. 9 is a schematic view of a position structure of a wire storage chamber in the multi-voltage output transformer of fig. 1.

Wherein like parts are designated by like reference numerals throughout the several views; the figures are not drawn to scale.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be considered a part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Examples

As shown in fig. 1 to 9, the multi-voltage output transformer in the present embodiment includes a primary coil 1210, a secondary coil 1220, an iron core 1300 and a casing 1100, wherein the iron core 1300 includes a movable iron core 1310 and a plurality of fixed iron cores 1320, the fixed iron cores 1320 are disposed around the movable iron core 1310, the movable iron core 1310 is rotatably connected to the casing 1100, a rotating device 1110 is disposed on the casing 1100, the rotating device 1110 is connected to the movable iron core 1310 to drive the movable iron core 1310 to rotate, the movable iron core 1310 is "C" shaped, and the rotation of the movable iron core 1310 can contact with upper and lower ends of the fixed iron core 1320 to form a closed magnetic path; the primary coil 1210 is wound on the plunger 1310, and the secondary coil 1220 is wound on the plunger 1320; taps of the primary coil 1210 and the secondary coil 1220 extend out of the housing 1100.

According to the scheme of this embodiment, the secondary coils 1220 wound on different fixed iron cores 1320 have different turns, the movable iron core 1310 is rotated to make the movable iron core 1310 contact with different fixed iron cores 1320 to form a closed magnetic circuit, and after alternating current is introduced into the primary coil 1210, the corresponding secondary coil 1220 generates induced electromotive force, thereby generating corresponding voltage; the device creatively adopts the annular arrangement of the secondary coils 1220, so that the structure is more compact, and the volume of the transformer is reduced; in the same or smaller internal volume of the casing 1100, more secondary coils 1220 can be accommodated, thus outputting more kinds of voltage to meet different electrical appliance usage; the secondary coil 1220 which is not required to be used improves the application efficiency of the magnetic flux because the fixed iron core 1320 cannot be in contact with the movable iron core 1310 to form a magnetic path, thereby improving the conversion efficiency of the transformer.

The inner cavity of the casing 1100 in this embodiment is filled with transformer oil, which can perform good heat dissipation and insulation functions, and can also perform a certain lubrication function on the rotation of the movable iron core 1310.

The rotating device 1110 is, for example, a rotating handle, and can be adjusted and rotated manually, and marks such as scales are arranged on the top of the casing 1100, so that the rotating handle can accurately correspond to corresponding output voltage in the rotating process; the rotating device 1110 may also be a servo motor or a stepping motor, and can rotate a certain angle according to a program setting, so as to output a corresponding output voltage.

The fixed iron core 1320 in this embodiment is located on the inner side surface of a cylinder, both ends of the fixed iron core 1320 are exposed out of the inner side surface of the cylinder, and the movable iron core 1310 can slide along the inner side surface of the cylinder when rotating and is sequentially in contact connection with one fixed iron core 1320; or the movable core 1310 is disposed on a cylinder, two ends of the movable core 1310 are exposed out of the outer surface of the cylinder, the surface of the cylinder is slidably connected to the fixed cores 1320, and when the cylinder rotates, the movable core 1310 is sequentially connected to the end face of one of the fixed cores 1320 in a contact manner.

In this embodiment or other embodiments, the housing 1100 is cylindrical, the stationary core 1320 is slidably connected to the housing 1100 in a radial direction, and a pressing device 1330 is disposed on an inner wall of the housing 1100, and the pressing device 1330 always applies a force to the stationary core 1320 toward the stationary core 1310. The compressing device 1330 can compress the fixed iron core 1320 to the movable iron core 1310, so that the two contacts are closer, the gap is reduced, the integrity of the magnetic path is improved, the loss of the gap between the movable iron core 1310 and the fixed iron core 1320 to the magnetic flux is reduced, and the conversion efficiency is further improved.

In this embodiment or other embodiments, the pressing device 1330 includes a spring 1331 and an insulating pad 1332, the insulating pad 1332 is fixed to the plunger 1320, and the spring 1331 is pressed between the insulating pad 1332 and the inner wall of the casing 1100; the arrangement of the insulating pad can reduce the influence of the magnetic flux on the spring; the fixed iron core can be ensured to be always in an insulation state in the shell;

the upper and lower ends of the fixed iron core 1320 are compressed by the compressing devices 1330. The two pressing devices 1330 press the upper end and the lower end of the fixed iron core 1320, so as to ensure the stability of the fixed iron core 1320 during movement, and further ensure the integrity of the magnetic path.

In this embodiment or other embodiments, a sliding sleeve 1340 is sleeved on the plunger 1310, the sliding sleeve 1340 is a cylindrical structure, an opening is disposed on one side of the sliding sleeve 1340, an end of the plunger 1310 exposes the sliding sleeve 1340 through the opening, and the plunger 1320 abuts against the sliding sleeve 1340 under the pushing of the pressing device 1330; the end of the plunger 1310 is exposed to the sleeve 1340, so that it can contact with the plunger 1320 to form a magnetic path.

When the movable iron core 1310 rotates, the sliding sleeve 1340 rotates along with the movable iron core 1310, so that the fixed iron core 1320 can slide along the periphery of the sliding sleeve 1340, the stability of the movable iron core 1310 during rotation is improved, smooth switching between the movable iron core 1310 and the fixed iron core 1320 is realized, the vibration during switching is greatly reduced, and the reliability and the service life of the device during use are improved.

The sliding sleeve 1340 in this embodiment is made of, for example, a ceramic material, and not only has a smooth surface, reduced friction force, and good wear resistance, but also can effectively play an insulating role, and improve safety and convenience in use.

In this embodiment or other embodiments, the fixed iron core 1320 is "C" shaped, both ends of the fixed iron core 1320 are arc concave surfaces, and the radian of the end surface of the fixed iron core 1320 is consistent with the radian of the outer surface of the sliding sleeve 1340; the end face of the movable iron core 1310 is an arc convex face matched with the end face of the fixed iron core 1320, and the arrangement can increase the contact area between the fixed iron core 1320 and the sliding sleeve 1340, so that the pressure per unit area is reduced, the abrasion between the fixed iron core 1320 and the sliding sleeve 1340 is reduced, and the service life of the device is prolonged;

this arrangement also provides a defined position between the stationary core 1320 and the plunger 1310, so that the plunger 1310 can be precisely inserted into the concave surface of the stationary core 1320 and tightly fit.

In this embodiment or other embodiments, the upper and lower ends of the inner side of the casing 1100 are both provided with the insulating strips 1130, the insulating strips 1130 are provided with the guide grooves 1131, the upper and lower ends of the fixed iron core 1320 are inserted into the guide grooves 1131 and slide along the guide grooves 1131, the guide grooves 1131 can further guide the movement of the fixed iron core 1320, the end of the fixed iron core 1320 can be ensured to be accurately contacted with the movable iron core 1310, and the stability and reliability of the device during use are improved.

In this embodiment or other embodiments, a plurality of protruding bars 1132 are disposed in the guide groove 1131 along the sliding direction of the fixed iron core 1320, and the protruding bars 1132 are disposed on two sidewalls and a bottom surface of the guide groove 1131. The contact area between guide groove 1131 and fixed iron core 1320 can be reduced to protruding strip 1132's setting, reduces the frictional force influence because of unevenness's contact surface causes, improves the guide effect.

The insulating strip 1130 in this embodiment is made of, for example, a ceramic material, and not only has a smooth surface, reduces friction force, and improves wear resistance, but also can effectively play an insulating role, and improve safety and convenience in use.

In this embodiment, the upper and lower sides of the end of the movable core 1310 are both protruded outward to form a first limiting portion 1311, the upper and lower sides of the end of the fixed core 1320 are recessed inward to form a second limiting portion 1321, and the first limiting portion 1311 and the second limiting portion 1321 are matched with each other to limit the vertical position of the movable core 1310, so as to ensure that the contact surface between the movable core 1310 and the fixed core 1320 is the largest, thereby maximally ensuring the integrity of the magnetic path.

In this embodiment or other embodiments, a connection base 1120 is disposed at the bottom of the casing 1100, a plurality of connection terminals 1121 are disposed on the connection base 1120 around the casing 1100, and taps of the primary coil 1210 and the secondary coil 1220 are respectively connected to the connection terminals 1121. The connection base 1120 can facilitate fixing an incoming tap 1211 of the primary coil 1210 and an outgoing tap 1221 of the secondary coil 1220, and facilitate external connection of electric equipment and a power line.

In this embodiment or other embodiments, the periphery of the casing 1100 is perpendicular to the wiring base 1120 and is provided with a plurality of wiring cavities 1101, taps of the secondary coil 1220 are connected to the wiring terminals 1121 through the wiring cavities 1101, sealing blocks are arranged at openings where the wiring cavities 1101 are communicated with the outside and the inner cavities of the casing 1100 and the wiring cavities 1101, and a certain length can be conveniently reserved for the taps of the secondary coil 1220 due to the arrangement of the wiring cavities 1101, so that the secondary coil 1220 can move a certain distance along with the fixed iron core 1320, the tap fracture caused by frequent pulling of the secondary coil 1220 is avoided, and the reliability of the device in use is improved.

In this embodiment or other embodiments, the upper and lower ends of the sliding sleeve 1340 both wrap the plunger 1310, so as to improve the sealing performance of the plunger 1310 and prevent the plunger 1310 from contacting the casing 1100, the upper and lower ends of the sliding sleeve 1340 are both rotatably connected to the casing 1100, and the rotating device 1110 penetrates through the casing 1100 and is connected to the sliding sleeve 1340; the bottom of the sliding sleeve 1340 is provided with a wire storage cavity 1341, the wire storage cavity 1341 is coaxially arranged with the sliding sleeve 1340, and the wire inlet tap 1211 of the primary coil 1210 is coiled at least one turn in the wire storage cavity 1341 and then connected to the corresponding wire connection terminal 1121 through the wire trough 1122 on the wire connection base 1120.

One or more circles of lines are wound in the line storage cavity 1341, so that the primary coil 1210 can conveniently rotate along with the movable iron core 1310, pulling damage to a tap due to an overlarge rotation angle is avoided, and the reliability of the device in use is further improved; and the disc-shaped coil can adapt to a certain rotation angle of the plunger 1320 without affecting the tap in the wiring slot 1122 or the sliding sleeve 1340.

In other embodiments, the taps in the wire storage chamber 1341 are wound in a spring shape, so that they can be stretched or shortened in the wire storage chamber 1341, and can be bent around the rotation shaft with the rotation of the movable core 1310, and the effect of preventing the pulling car from being damaged can also be achieved.

One technical effect of this embodiment is that the device pioneering uses secondary coils arranged in a ring shape, which is more compact and helps to reduce the size of the transformer;

Although some specific embodiments of the present invention have been described in detail by way of illustration, it should be understood by those skilled in the art that the above illustration is only for the purpose of illustration and is not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A multi-voltage output transformer comprises a primary coil, a secondary coil, an iron core and a shell, and is characterized in that the iron core comprises a movable iron core and a plurality of fixed iron cores, the fixed iron cores are arranged around the movable iron core, the movable iron core is rotatably connected into the shell, a rotating device is arranged on the shell, the rotating device is connected onto the movable iron core to drive the movable iron core to rotate, the movable iron core is C-shaped, and the rotation of the movable iron core can be in contact with the upper end and the lower end of the fixed iron core to form a closed magnetic circuit; the primary coil is wound on the movable iron core, and the secondary coil is wound on the fixed iron core; taps of the primary coil and the secondary coil extend out of the shell; the shell is cylindrical, the fixed iron core is connected into the shell in a sliding mode in the radial direction, a pressing device is arranged on the inner wall of the shell, and the pressing device always applies force towards the movable iron core to the fixed iron core; the pressing device comprises a spring and an insulating pad, the insulating pad is fixed on the fixed iron core, and the spring is pressed between the insulating pad and the inner wall of the shell; the upper end and the lower end of the fixed iron core are respectively compressed with the compressing devices; the movable iron core is sleeved with a sliding sleeve, the sliding sleeve is of a cylindrical structure, an opening is formed in one side of the sliding sleeve, the end portion of the movable iron core is exposed out of the sliding sleeve through the opening, and the fixed iron core is pushed by the pressing device to abut against the sliding sleeve.

2. The multi-voltage output transformer of claim 1, wherein the fixed iron core is C-shaped, both ends of the fixed iron core are arc concave surfaces, and the radian of the end surface of the fixed iron core is consistent with the radian of the outer surface of the sliding sleeve; the end face of the movable iron core is an arc convex face matched with the end face of the fixed iron core.

3. A multi-voltage output transformer according to claim 2, wherein the inside of the case is provided at upper and lower ends thereof with insulating bars, the insulating bars are provided with guide grooves, and upper and lower ends of the stationary core are inserted into and slid along the guide grooves.

4. A multi-voltage output transformer according to claim 3, wherein a plurality of protruding bars are provided in the guide groove in a direction in which the stationary core slides, the protruding bars being provided on both side walls and a groove bottom surface of the guide groove.

5. A multi-voltage output transformer according to claim 1, wherein a wiring base is provided on the bottom of the housing, a plurality of terminals are provided on the wiring base around the housing, and taps of the primary coil and the secondary coil are connected to the terminals, respectively.

6. The multi-voltage output transformer according to claim 5, wherein a plurality of wiring cavities are formed in the periphery of the housing perpendicular to the wiring base, taps of the secondary coils are connected to the wiring terminals through the wiring cavities, and sealing blocks are arranged at openings where the wiring cavities are communicated with the inner cavity of the housing and the outside.

7. The multi-voltage output transformer of claim 5, wherein the movable iron core is wrapped by both the upper and lower ends of the sliding sleeve, both the upper and lower ends of the sliding sleeve are rotatably connected to the housing, and the rotating device penetrates through the housing and is connected to the sliding sleeve; the wire storage cavity is formed in the bottom of the sliding sleeve and is coaxially arranged with the sliding sleeve, and a tap of the primary coil is coiled in the wire storage cavity for at least one circle and then is connected to a corresponding wiring terminal through a wiring groove in the wiring base.