JP2000012336A - Balance coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drop and damage of a core by accommodating the molding error of a bobbin to ensure a proper torque when inserting a screw core into the bobbin. SOLUTION: A bobbin has a junction portion 22 which joins a spool 21 with first coil wound therearound to a spool 23 with second coil wound therearound. A notch 32 is provided at the junction portion 22, and a thread 31 is formed in the internal surface of the junction portion 22. Furthermore, the junction portion 22 is pinched by a stopper 5 which is formed of a flexible member and has a pair of pawls 51 and 52 and a pair of presser pieces 53 and 54 pressing a screw core 4 through the notch 32. The presser pieces 53 and 54 allows a proper torque when inserting the core into the bobbin. As a result, variations in dimensions of the bobbin during molding can be accommodated to prevent the core from coming off or being cracked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance coil suitable for use in, for example, a convergence correction circuit for correcting misconvergence in a color CRT.

[0002]

2. Description of the Related Art In a color CRT, it is known that symmetric vertical misconvergence occurs near both right and left ends of a horizontal scanning axis. In order to correct such a symmetric vertical misconvergence, a balance coil capable of changing the inductance differentially is used. The balance coil has a structure in which two coils are wound around a bobbin that shares one core, and in this state, the core in the bobbin is moved to change the inductance.

FIGS. 4A and 4B show an example of a conventional balance coil. 4A is a front view of the balance coil, and FIG. 4B is aa ′ in FIG. 4A.
FIG. 4A and 4B, reference numeral 101 denotes the entire balance coil, and the balance coil 101 includes a bobbin, one screw-type core 104, and a copper wire (not shown) coated with insulation.

[0004] As shown in FIGS. 4A and 4B, the bobbin is composed of a hollow cylindrical body and partition plates 111, 112, 113, 1.
14 are integrally formed. A winding frame 121 around which the first coil is wound is formed between the partition plate 111 and the partition plate 112, and a winding frame 123 around which the second coil is wound between the partition plate 113 and the partition plate 114. Is formed, and the reel 12 is interposed between the partition plate 112 and the partition plate 113.
A relay section 122 that connects 1 and 123 is formed. The bobbin has a through hole 110 for inserting the screw core 104. A plurality of ribs 131 extending in the axial direction are formed on the inner peripheral surface of the bobbin.

[0005] A first coil is formed by winding an insulated copper wire around the winding frame 121, and terminals are respectively drawn out from both ends of the copper wire to form a first coil. The wound copper wire is wound, and a terminal is led out from both ends of the copper wire to form a second coil.
Further, the screw core 104 is inserted into the bobbin by inserting the screw core 104 into the through hole 110 while rotating the screw core 104. That is, when the screw-type core 104 is rotated, the screw-type core 104 is inserted into the rib 131 while cutting the thread.

[0006]

In the above-described conventional balance coil, the screw-type core is screwed into the rib provided on the inner peripheral surface of the bobbin, and the screw-type core is attached to the bobbin. I have. Therefore, the size of the bobbin inner diameter is affected by variations due to manufacturing errors,
The securing of the rotational torque tends to be unstable. For example, if the inner diameter is larger than the specified value, the locking of the screw-type core is loose, so that there is a problem that the core falls. If the inner diameter is smaller than the specified value, the screw core may be broken.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a balance coil which can secure an optimum torque when inserting a screw-type core and can prevent the core from dropping or breaking.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that first and second coils are wound around a bobbin and a core is inserted into the bobbin. In a balance coil that changes the inductance of each of the first and second coils differentially,
A hollow cylindrical bobbin having a bobbin around which the first coil is wound, a bobbin around which the second coil is wound, and a relay portion connecting the two bobbins; A notch formed on the surface, and a protrusion for locking the core formed on the inner surface of the relay portion,
A balance coil comprising a stopper having a holding piece for holding down a core inserted into a bobbin through a notch.

According to the present invention, a notch is provided in a relay portion connecting the winding frame around which the first coil is wound and the winding frame around which the second coil is wound, and a projection such as a protrusion is formed on the inner surface of the relay portion. A thread is provided, and a stopper having a retaining piece that holds down the core through the notch is attached. For this reason, the core may drop due to variations in the dimensions at the time of bobbin molding,
It is possible to prevent the core from cracking and the rotation torque from becoming unstable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a front view of an embodiment of the present invention, and FIG.
It is sectional drawing of a '. In FIG. 1A and FIG. 1B, reference numeral 1 indicates the entire balance coil. In FIG. 1, a stopper described below is not attached.

The bobbin constituting the balance coil 1 is integrally formed by injection molding, and is formed of a member having excellent wear resistance, heat resistance and dimensional stability.
For example, PET (polyethylene terephthalate) is used as the member. Note that a mixture of PET and glass fiber may be used.

As shown in FIGS. 1A and 1B, a bobbin has four partition plates 11, 12, 1 with respect to a hollow cylindrical body.
3 and 14 are formed integrally. A winding frame 21 around which the first coil is wound is formed between the partition plate 11 and the partition plate 12, and a winding frame 23 around which the second coil is wound between the partition plate 13 and the partition plate 14. Is formed, and the partition plate 12 is formed.
A relay portion 22 for connecting the bobbins 21 and 23 to the partition plate 13 is formed between the winding frame 21 and the partition plate 13.

The bobbin has a through hole 10 into which the screw core 4 is inserted. Tapered portions 15 and 16 are provided at both ends of the through hole 10. Relay part 2
2 is provided with a notch 32 for opening the through-hole 10 in a substantially semicircular cross section, and a thread 31 corresponding to the pitch of the screw-type core 4 is formed on the inner peripheral surface of the relay portion 22. Is provided. In this case, the screw type core 4
Although the screw thread 31 is formed in order to lock the shape, other convex shapes may be used.

Although not shown, the winding wire 21 is wound with a predetermined number of insulated copper wires, and terminals are respectively led out from both ends of the copper wire to form a first coil. A second coil is formed by winding a predetermined number of copper wires insulated on the winding frame 23 and leading terminals from both ends of the copper wire.

The screw-type core 4 is made of, for example, ferrite, has a screw shape formed on its peripheral surface, and has a through-hole having a hexagonal cross section. A jig is inserted into this through hole, and the screw type core 4 is inserted into the through hole 10 of the bobbin while rotating, so that the screw type core 4 is attached to the bobbin. That is, when the screw-type core 4 is rotated, the screw-type core 4 moves as indicated by an arrow in the figure while being guided by the screw thread 31. The inductance of the two coils can be adjusted by the insertion amount of the core 4.

When the screw type core 4 is moved,
Since a substantially half portion of the relay portion 22 of the bobbin is opened by the notch 32, there is little contact resistance between the core 4 and the inner peripheral surface of the relay portion 22, so that the screw type core 4 can be easily formed. Can be inserted.

In order to fix the inserted state of the screw type core 4, a stopper is further attached. FIG. 2B
FIG. 2A is a side view showing a state after a stopper is attached to the relay portion 22 of the bobbin, and FIG. 2A is a view bb ′ of FIG. 2B.
It is sectional drawing in the position of. 2A and FIG.
Reference numeral 5 in B denotes a stopper. Also,
2A and 2B, parts corresponding to those in FIGS. 1A and 1B are denoted by the same reference numerals.

The stopper 5 attached to the relay portion 22 of the bobbin is integrally formed by injection molding, and is excellent in abrasion resistance, heat resistance and dimensional stability, and has high elasticity and flexibility. It is formed by a member. For example, modified PPE (polyphenylene ether) is used as the member. Note that a mixture of PPE and glass fiber may be used.

As shown in FIG. 2A, the shape of the stopper 5 is substantially U-shaped in cross section, and the width w in the axial direction (see FIG. 2B) is slightly shorter than the width of the relay portion 22. I have. A pair of claws 5 that engage with ribs 33 and 34 protruding from the outer periphery of the relay portion 22 of the bobbin are provided at the end of the stopper 5.
1, 52 are provided. Further, inside the stopper 5, a pair of holding pieces 53, 54 that press the screw type core 4 through the notch 32 of the relay portion 22 are provided. These 5
1, 52 and the holding pieces 53, 54 also have a width w and have elasticity.

As shown in FIG. 4A, ribs 33, 34,
The nails 51 and 52 are locked, and the outer peripheral surface of the screw type core 4 is
Stopper 5W in a state where the pressing pieces 53 and 54 are in contact with each other.
Attached. As a result, the core 4 holds the holding pieces 53,
It is in a state of being held down by the elastic force of 54, and it is possible to stably secure the rotational torque when the screw type core is rotationally moved.

FIG. 3 shows a balance coil 1 according to the present invention.
Shows a specific example of a convergence correction circuit actually used. In FIG. 3, a portion surrounded by a broken line 1 is a balance coil according to the present invention. The coil indicated by 1a corresponds to the first coil, and the coil indicated by 1b corresponds to the second coil. In FIG. 3, reference numeral 62a denotes one upper horizontal deflection coil provided in the vicinity of the funnel portion of the cathode ray tube, and reference numeral 62b denotes the other lower horizontal deflection coil.

One end of the upper horizontal deflection coil 62a and one end of the lower horizontal deflection coil 62b are connected to each other, and a terminal 61 is led out from the common connection point. Upper horizontal deflection coil 62a
Is connected to one end of the first coil 1a of the balance coil 1, and the other end of the lower horizontal deflection coil 62b is connected to one end of the second coil 1b of the balance coil 1. The other end of the first coil 1a of the balance coil 1 and the other end of the second coil 1b of the balance coil 1 are connected to each other, one end of the coil 63 is connected to this common connection point,
A terminal 64 is led out from the other end of the coil 63. Although not shown, this terminal 64 is grounded via a capacitor for S-character correction.

In one embodiment of the present invention,
A case has been described in which the notch 32 is provided in the relay portion 22 of the bobbin so as to open the through hole 10 in a substantially semicircular cross section. The present invention is not limited to the shape and number of the notches 32.

[0024]

According to the present invention, a notch is provided on the peripheral surface of the relay portion, and a thread or a convex shape for locking the screw core is provided on the inner surface of the relay portion. The stopper is attached with the core sandwiched. Therefore,
According to the present invention, it is possible to prevent the core from falling or the core from being broken due to variation in dimensions at the time of bobbin molding, and it is possible to stably secure a rotational torque when the core is rotationally moved. .

[Brief description of the drawings]

FIG. 1 is a front view and a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view and a side view of an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of using a balance coil according to the present invention.

FIG. 4 is a front view and a cross-sectional view used for describing a conventional balance coil.

[Explanation of symbols]

1 ... balance coil, 4 ... screw type core, 5 ...
· Stopper, 10 · · · through hole, 21 · 23 · · · winding frame, 22 · · · relay portion, 31 · · · thread, 32 · · · ·
Notch, 51, 52 ... claw, 53, 54 ... holding piece

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C042 HH01 HH02 HH11 HH16 5C060 CF01 CN01 JA25 5E070 AA16 AB10 BA07 CA12 CA20 KE02

Claims (3)

[Claims] 1. By winding first and second coils on a bobbin and inserting a core into the bobbin,
In a balance coil that changes each inductance of the first and second coils differentially, a bobbin around which the first coil is wound, and a bobbin around which the second coil is wound A hollow cylindrical bobbin having a relay portion connecting the two winding frames, a notch formed on the peripheral surface of the relay portion, and a convex portion for locking the core formed on the inner surface of the relay portion. And a stopper having a holding piece for holding down the core inserted into the bobbin through the notch. 2. The balance coil according to claim 1, wherein the notch is formed so as to open the bobbin substantially in a semicircular cross section. 3. The balance coil according to claim 1, wherein the stopper further has a claw portion that is engaged with a relay portion of the bobbin.