JP4711064B2 - Ring varistor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a ring varistor and a method for manufacturing the same.

  An important application of this type of ring varistor is as a noise absorbing element that absorbs noise generated in a commutator of a small DC motor. In such an application, as a means for electrically connecting the ring varistor and the riser, conventionally, the ring varistor is directly soldered to the riser as described in Patent Document 1, for example.

  However, when solder is used, a troublesome cleaning operation is required, and it is difficult to position the ring varistor on the riser.

  Therefore, as a means for solving the above-mentioned problems associated with soldering the ring varistor directly to the riser, a tab made of a thin metal plate is joined to the electrode of the ring varistor so that the riser can be connected to this tab. A structure has been proposed. When the tab is joined to the electrode of the ring varistor, solder is attached to the electrode from above the tab, but soldering is not performed when the ring varistor is connected to the riser.

  According to this technique, since no solder is used when the ring varistor and the riser are electrically connected, no cleaning is possible. Moreover, the advantage that a tab can be used also for positioning at the time of attaching to a commutator is also acquired.

However, when joining the tab to the electrode of the ring varistor, the solder that adheres from the top of the tab causes the joint material to swell or the amount of adhesion fluctuates. There is a problem that the motor becomes a defective product.
Japanese Patent Laid-Open No. 2003-199298

  An object of the present invention is to provide a ring varistor capable of firmly and reliably bonding a tab to an electrode of a varistor element without causing the bonding material to rise.

  Still another object of the present invention is to provide a manufacturing method suitable for manufacturing the above-described ring varistor.

  In order to solve the above-described problems, a ring varistor according to the present invention includes a varistor element and a tab. The varistor element has an electrode on at least one surface of a ring-shaped varistor element body. The tab is made of a thin metal plate and has a through slit or a through hole, and is joined to the electrode of the varistor element by a joining material supplied into the through slit or the through hole. “Penetration” means that the tabs are missing on both sides in the thickness direction.

  As described above, in the present invention, the tab has a through slit or a through hole (hereinafter referred to as a notch), and is joined to the electrode of the varistor element by the joining material supplied to the notch. , It is possible to avoid the bonding material from rising over the surface of the tab. Therefore, there is no trouble in mounting to the small DC motor due to the rising of the bonding material.

  In addition, the electrode provided on the varistor element body and the tab can be directly joined by the joining material supplied to the notch. Therefore, the tab can be firmly bonded to the electrode of the varistor element. Since the bonding material such as solder diffuses and adheres to the contact interface between the electrode and the tab, a stronger bonding structure can be obtained.

  The present invention further discloses a method suitable for manufacturing the ring varistor described above. In this manufacturing method, first, a tab having a notch in the surface is arranged on the electrode of the varistor element having an electrode on one surface. Next, a predetermined amount of the melt bonding material is supplied to the notch portion at a distance from the surface of the tab. Then, the tab is joined to the electrode.

  As described above, in the present invention, since the molten bonding material is supplied into the notch portion at a distance from the tab, the molten bonding material is almost entirely omnidirectionally on the electrode surface in the notch portion according to its own flow diffusibility. It is possible to flow and diffuse uniformly.

  In addition, since a predetermined amount of the molten bonding material is supplied to the cutout portion at a distance from the surface of the tab, the layer thickness of the bonding material is controlled to a constant value within the cutout portion, and exceeds the surface of the tab. Phenomena such as excitement can be avoided. When a soldering iron or the like is used, an unspecified amount of solder adheres to the soldering iron, so that such a quantitative supply cannot be realized at all, and the joining material swells up.

  In addition, since the external force on the ring varistor is only the weight of the fusion bonding material, even a ring varistor having a low mechanical strength is not damaged. The method of dropping the molten bonding material onto the surface of the electrode by utilizing natural fall belongs to a very simple method for preventing an excessive external force from causing damage to the ring varistor. If this is the case, if a soldering iron is used, the ring varistor with low mechanical strength may be damaged by the thermal and mechanical impact. In order to facilitate the dripping of the molten bonding material, a process or an aspect such as applying mechanical vibration to the molten bonding material or applying weak warm air from the inside of the dropping nozzle may be included.

  The manufacturing method according to the present invention preferably includes at least a step of preheating the tab and the varistor element body. The effect of this preheating is particularly remarkable in a thin ring varistor. This is because it is possible to avoid the varistor element body from being damaged by thermal shock.

  As a specific aspect of supplying a predetermined amount of the molten bonding material, a bonding material having a predetermined volume is supplied to the heating unit, and the supplied bonding material is melted in the heating unit to obtain a predetermined amount of the molten bonding material. A configuration can be employed. In this case, the melt bonding material supply port of the heating unit is set at a position separating a predetermined spatial distance from the notch.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

  FIG. 1 is a plan view of a ring varistor, and FIG. 2 is an enlarged partial sectional view taken along line 2-2 of FIG. The illustrated varistor includes a varistor element 40 and tabs 51 to 53. The varistor element 40 has a center hole 45 through which a rotating shaft of a small DC motor passes, and corresponds to the number of armature poles of the small DC motor on one surface of a varistor element body 41 formed in an appropriate shape such as an annular shape. The plurality of electrodes 42 to 44 are provided. The electrodes 42 to 44 are provided with insulating gaps G1 to G3. In the drawing, only three electrodes 42 to 44 are shown, but the number is selected according to the number of armature poles of the small DC motor.

  The tabs 51 to 53 are made of a thin metal plate, have notches 511 to 531 in the plane, and are bonded to the electrodes 42 to 44 of the varistor element 40 by the bonding materials 21 to 23 attached to the notches 511 to 531. It is joined. The tabs 51 to 53 are made of a metal material having good electrical conductivity, typically a thin plate mainly composed of Cu. Since a riser is connected to the tabs 51 to 53 later, a structure suitable for the riser is given. For example, in the case of the figure, the outer end portions 512 to 532 of the tabs 51 to 53 are projected outward from the outer periphery of the varistor element 40, and the outer end portions 512 to 532 are used for the riser connection. It has become.

  On the other hand, the inner ends 513 to 533 of the tabs 51 to 53 are bent along the inner wall surface of the center hole 45 provided in the varistor element 40. With such a structure, the pull-out strength of the tabs 51 to 53 is improved. However, it is not always necessary to bend it. The notches 511 to 531 are one circular hole in the drawing, but the shape and the number thereof may be arbitrary. It may be a square hole or a through slit. Further, a plurality of them may be provided.

  As the bonding materials 21 to 23, in addition to normal solder, solder not containing lead or a low-temperature brazing material can be used. A specific example of the solder not containing lead is mainly composed of Sn. It is important that the bonding materials 21 to 23 be attached so as not to protrude outside the notches 511 to 531, that is, so as not to rise above the surfaces of the tabs 51 to 53.

  In the present invention, the tabs 51 to 53 have notches 511 to 531 in the plane, and are joined to the electrodes 42 to 44 of the varistor element 40 by the joining materials 21 to 23 supplied to the notches 511 to 531. Therefore, the joining materials 21 to 23 can be prevented from rising over the surfaces of the tabs 51 to 53.

  In addition, the electrodes 42 to 44 provided on the varistor element body 41 and the tabs 51 to 53 can be directly joined by the joining materials 21 to 23 supplied to the notches 511 to 531. Therefore, the tabs 51 to 53 can be firmly bonded to the electrodes 42 to 44 of the varistor element 40.

  The bonding materials 21 to 23 are diffused and adhered over the entire surface of the notches 511 to 513 and between the contact surfaces of the tabs 51 to 53 and the electrodes 42 to 44. The bonding force between 53 and the electrodes 42 to 44 can be significantly increased.

  The tabs 51-53 can take various shapes and structures. An example is shown in FIGS. In the figure, parts corresponding to the constituent parts appearing in FIGS. 1 and 2 are given the same reference numerals.

  FIG. 3 is a plan view showing another embodiment of the ring varistor according to the present invention, and FIG. 4 is an enlarged partial sectional view taken along line 4-4 of FIG. In this embodiment, the notches 511 to 531 are square holes, and the bonding materials 21 to 23 are supplied to the square holes so as not to rise. Similar to the embodiment of FIGS. 1 and 2, the bonding materials 21 to 23 are not only inside the notches 511 to 513 but also between the contact surfaces of the tabs 51 to 53 and the electrodes 42 to 44. Accordingly, the bonding force between the tabs 51 to 53 and the electrodes 42 to 44 can be significantly increased.

  FIG. 5 is a plan view showing still another embodiment of the ring varistor according to the present invention, and FIG. 6 is an enlarged partial sectional view taken along line 6-6 of FIG. Referring to the figure, each of the tabs 51 to 53 has a structure in which a plurality of cutout portions 511 to 531 by through slits are provided side by side, and the bonding materials 21 to 23 are raised in the cutout portions 511 to 531, respectively. Not to be attached.

  In addition, as is apparent from FIG. 6, the bonding materials 21 to 23 include the notches 511 to 511 adjacent to the inside of the notches 511 to 513 and the outer periphery of each of the tabs 51 to 53. Also between the branch portions between 521 to 521 and 531 to 531 and the contact surfaces of the electrodes 42 to 44, diffusion adheres over the entire surface. For this reason, the tabs 51 to 53 and the electrodes 42 to 44 are bonded extremely firmly.

  FIG. 7 is a plan view showing still another embodiment of the ring varistor according to the present invention, and FIG. 8 is an enlarged partial sectional view taken along line 8-8 in FIG. In this embodiment, the notches 511 to 531 are formed around the center hole 45, and the bonding materials 21 to 23 are supplied so as not to rise. The bonding materials 21 to 23 are diffused and adhered over the entire surface of the notches 511 to 513 and between the contact surfaces of the tabs 51 to 53 and the electrodes 42 to 44. The bonding force between 53 and the electrodes 42 to 44 can be significantly increased. The notches 511 to 531 have one end closed and the other end opened, and the joining materials 21 to 23 are limited to such an amount that does not flow out to the outside on the opening side.

  As described above, since any of the ring varistors illustrated in FIGS. 1 to 8 is supplied to the inside of the notches 511 to 531 so that the bonding materials 21 to 23 are not raised, the bonding material is raised. It does not cause a failure to attach to the small DC motor. In addition, since it diffuses widely on the contact surfaces of the tabs 51 to 53 and the electrodes 42 to 44 and a strong joining structure is realized, sufficient mechanical strength can be ensured even when attached to a small DC motor. it can.

  Next, this point will be described with reference to FIG. FIG. 9 is a partial sectional view showing a part of a small DC motor using the ring varistor according to the present invention as a noise absorbing element. In the small DC motor 6, a stator (field) 62 is provided inside the exterior body 61, and an armature 63 is arranged inside the stator 62. A plurality of commutator pieces 65 divided according to the number of poles of the armature 63 are coaxially arranged on the rotating shaft 64 attached to the armature 63. The armature 63 is insulated from the rotating shaft 64 by an insulator 66.

  Each of the commutator pieces 65 has a riser 67 that rises in the direction of the rotation diameter at one end on the armature 63 side, and an armature winding 68 is attached to the riser 67 with a bonding material 69 or the like. Connected by means of.

  The noise absorbing element 4 is mounted on the surface of the riser 67 opposite to the surface facing the armature 63 in a state of facing. The noise absorbing element 4 is the ring varistor shown in FIGS. A riser 67 connected to the commutator piece is connected to the tabs 51 to 53.

  Here, since the bonding materials 21 to 23 for bonding the tabs 51 to 53 and the electrodes 42 to 44 are supplied so as not to rise beyond the surfaces of the tabs 51 to 53, the noise absorbing element 4 is configured to be the riser 67. On the other hand, it joins in a parallel state, without producing an inclination.

  Next, a method for manufacturing the ring varistor according to the present invention shown in FIGS. 1 to 8 will be described with reference to FIGS. First, as shown in FIG. 10, a cutting portion 1 that cuts a continuously supplied rod-shaped bonding material 2 with a fixed size and a lower portion of the cutting portion 1 so that the cutting portion 1 has a fixed size. A heating unit 3 is prepared for heating and melting the cut pieces of bonding material. As the bonding material 2, a normal solder containing Pb, a solder not containing Pb, a low-temperature melting brazing material, and the like are used. The heating unit 3 includes a heating element, and a nichrome heater or a ceramic heater is employed as the heating element. Moreover, the aspect which integrated the heating element and the nozzle using the ceramic heater may be sufficient.

  A varistor element 40 is disposed below the heating unit 3 with a gap D1 therebetween. The tab structure of the varistor element 40 may be any of those shown in FIGS. 1 to 8, but first, the order will be described from the manufacture of the ring varistor shown in FIGS.

  The varistor element 40 has a structure in which electrodes 42 to 44 are formed on one surface of a varistor element body 41, and tabs 51 to 53 are disposed on the surfaces of the electrodes 42 and 44. The notches 511 to 531 of the tabs 51 to 53 are positioned directly below the melting wax discharge port 31 of the heating unit 3. The distance (height) D1 from the surface of the tabs 51 to 53 to the molten bonding material discharge port 31 of the heating unit 3 is such that the molten bonding material supplied from the heating unit 3 is not cooled substantially. The dimensions supplied to the cutout portions 511 to 531 of 51 to 53 are set.

  In supplying the molten bonding material to the notches 511 to 531, first, as shown in FIG. 10, the bonding material 2 is fed by a fixed size in the direction indicated by the arrow X, and then, as shown in FIG. 11, The cutting part 1 is moved in the direction indicated by the arrow Y, and the tip part of the bonding material 2 is cut with a fixed dimension L1.

  The cut piece 2 of bonding material falls into the heating unit 3 as shown by an arrow Y1 in FIG. 12, and is heated and melted inside the heating unit 3. In FIG. 12, the bonding material piece 2 is drawn so as to fall freely, but the heating unit 3 temporarily holds the bonding material piece 2 and heats it to a molten state.

  The bonding material piece 2 is melted by the heating unit 3 and becomes a molten bonding material 20 as shown in FIG. The melt bonding material 20 is supplied from the outlet of the superheated portion 3 toward the notches 511 to 531 as indicated by an arrow Y2. Then, as shown in FIG. 14, the fusion bonding material 20 adheres to the surfaces of the electrodes 42 to 44 in the notches 511 to 531, and due to its own fluidity, as shown in FIG. It diffuses and solidifies on the surface so as to have a uniform thickness in all directions. The tabs 51 to 53 are bonded to the surfaces of the electrodes 42 to 44 by the solidified bonding materials 21 to 23.

  16 and 17 are enlarged views conceptually showing the behavior of the molten bonding material 20 in the process from FIG. 14 to FIG. 15. For the sake of concrete explanation, the description will be made focusing on the notch portion 511 of the tab 51. The melt bonding material 20 supplied to the inside of the notch portion 511 is as shown by an arrow F1 in FIG. The fluid diffuses to the contact interface between the tab 21 and the electrode 42 in all directions from the inside of the notch 511. As a result, after the molten bonding material 20 has diffused and solidified, as shown in FIG. 17, the bonding material 21 has not only the inside of the notch 511 but also the contact interface between the electrode 42 and the tab 51. Since it adheres over the whole surface, a very strong joining structure can be obtained.

  In addition, since a predetermined amount of the molten bonding material 20 is supplied to the cutout portion 511 at a distance from the surface of the tab 51, the layer thickness of the bonding material 21 inside the cutout portion 511 is controlled to a constant value. 21 can be prevented from rising beyond the surface of the tab 51.

  Further, since the melt bonding material 20 is supplied into the notch 511 at a distance from the tab 51, the external force on the varistor element 40 is only the weight of the melt bonding material 20. For this reason, even the varistor element 40 with low mechanical strength is not damaged. In the case of the illustrated embodiment, the molten bonding material 20 is dropped into the notch 511 by using natural fall. This method belongs to a very simple method for not applying an excessive external force that causes damage to the varistor element 40.

  Furthermore, by setting the volume of the molten bonding material 20 to a value that takes into account the volume of the cutout portion 511, the thickness of the solidified bonding material 21 can be set to a constant value that does not protrude from the cutout portion 511. .

  The same process is performed for the other tabs 52 and 53, and the bonding materials 22 and 23 are not only inside the notches 521 and 531 but also the entire contact interface between the electrodes 43 and 44 and the tabs 52 and 53. Therefore, an extremely strong joint structure can be obtained.

  In joining, it is preferable to include a step of preheating at least the surfaces of the electrodes 42 to 44 and the tabs 51 to 53. The preheating temperature is suitably in the range of 50 to 250 ° C. Thereby, the thermal damage of the ring varistor 4 can be prevented.

  Next, the case where the method according to the present invention is applied to the production of the ring varistor shown in FIGS. 18 to 22 are enlarged views conceptually showing the behavior of the molten bonding material 20 in the process from FIG. 14 to FIG. 15 when the ring varistor shown in FIGS. 5 and 6 is manufactured. 18 is a plan view of the varistor element 40, FIG. 19 is an enlarged partial sectional view taken along line 19-19 in FIG. 18, and FIG. 20 is an enlarged partial sectional view taken along line 20-20 in FIG. 21 is a diagram showing a state after the fusion bonding material 20 has diffused, and is an enlarged partial sectional view at the same cross-sectional position as FIG. 19, and FIG. 22 is a diagram showing a state after the fusion bonding material 20 has been diffused. It is an expanded partial sectional view in the same cross-sectional position.

  As shown in FIG. 18, for example, the melt bonding material 20 supplied into the notch 511 provided at the center of the tab 51 is notched according to its own flow diffusibility, as indicated by an arrow F <b> 1. From the inside of 511 to all directions, it also flows and diffuses at the contact interface between tab 21 and electrode 42. As a result, after the fusion bonding material 20 is solidified, as shown in FIG. 17, in addition to the inside of the notch portion 511 and the outer peripheral portion, the branch portion between the adjacent notch portions 511-511, the electrode 42, Since the bonding material 21 adheres over the entire contact surface, the tab 51 and the electrode 42 are bonded extremely firmly.

  Other functions and effects are the same as described with reference to FIGS. 16 and 17 and thus will not be described.

  23 to 25 are enlarged views conceptually showing the behavior of the molten bonding material 20 in the process from FIG. 14 to FIG. 15 when the ring varistor shown in FIGS. 7 and 8 is manufactured. 23 is a plan view of the varistor element 40, FIG. 24 is an enlarged partial cross-sectional view taken along line 24-24 of FIG. 23, and FIG. 25 is a diagram showing a state after the molten bonding material 20 is diffused from the state of FIG. FIG. 25 is an enlarged partial cross-sectional view at the same cross-sectional position as FIG. 24.

  As shown in FIG. 23, the melt bonding material 20 supplied to the inside of the notch 511 provided in the tab 51 follows the self-flow diffusibility of the notch 511 as shown by an arrow F1 in FIG. It flows and diffuses to the contact interface between the tab 21 and the electrode 42 in all directions from the inside. As a result, after the molten bonding material 20 is solidified, as shown in FIG. 25, the bonding material 21 extends not only inside the notch 511 but also between the outer peripheral portion and the contact surface between the electrodes 42 over the entire surface. Therefore, the tab 51 and the electrode 42 are bonded extremely firmly. The cutout portion 511 has one end closed and the other end opened, and the bonding material 21 is limited to an amount that does not flow out to the outside on the opening side.

  Other functions and effects are the same as described with reference to FIGS. 16 and 17 and thus will not be described. 16 to 25, only the supply process of the molten bonding material 20 to the tab 21 has been described. However, the same process is performed for the other tabs 52 and 53, and the bonding material 22 is also applied to the tabs 52 and 53. , 23 adheres not only inside the notches 521 and 531, but also over the entire contact interface between the electrodes 43 and 44 and the tabs 52 and 53, so that an extremely strong bonding structure can be obtained.

  The advantages of the present invention described above become clearer when compared with the case of using a conventional soldering iron. Next, a conventional technique using a soldering iron will be described with reference to FIGS. 26 is a plan view showing the arrangement state of the varistor element 40 and the tabs 21 to 23 when the tab joining method using the soldering iron is used, and FIG. 27 is an enlarged partial sectional view taken along the line 27-27 in FIG. It is a figure which shows the joining method.

  As shown in FIG. 26, when the tab 21 is disposed on the electrode 42 of the varistor element 40, the solder 20 is adhered around the electrode 21, and the solder 20 is melted with a solder iron as shown in FIG. Since an unspecified amount of solder adheres to 201, the amount of solder to be used for bonding between the tab 21 and the electrode 42 is not constant, and a portion 201 in which no solder exists between them is generated, and bonding is not performed. Insufficient, or conversely, solder swells. Moreover, if a soldering iron is used, the ring varistor with low mechanical strength may be damaged by the thermal and mechanical impact.

  In order to solve the problems as described above, as shown in FIG. 28 and FIG. 29, the solder that is the bonding materials 24 to 26 must be attached so as to rise on the tabs 51 to 53, While increasing the thickness, the raised heights of the bonding materials 24 to 26 are uneven. For this reason, when the obtained ring varistor is connected to the riser 67 of the small DC motor shown in FIG. 6, an assembly failure such as the riser 67 tilting is caused.

  According to the present invention, it is clear from the explanation already made that all the problems of the prior art described above can be solved.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

It is a top view of the ring varistor which concerns on this invention. It is an expanded partial sectional view of the ring varistor shown in FIG. It is a top view in another Example of the ring varistor which concerns on this invention. It is a top view in another Example of the ring varistor which concerns on this invention. FIG. 5 is a plan view showing still another embodiment of the ring varistor according to the present invention. FIG. 6 is an enlarged partial sectional view taken along line 6-6 of FIG. It is a top view which shows another Example of the ring varistor which concerns on this invention. FIG. 8 is an enlarged partial sectional view taken along line 8-8 in FIG. 7. It is a fragmentary sectional view showing a part of small DC motor which used the ring varistor concerning the present invention as a noise absorption element. It is a figure which shows the manufacturing method of the ring varistor which concerns on this invention. It is a figure which shows the process after the process shown in FIG. FIG. 12 is a diagram showing a step after the step shown in FIG. 11. FIG. 13 is a diagram showing a step after the step shown in FIG. 12. FIG. 14 is a diagram showing a step after the step shown in FIG. 13. It is a figure which shows the process after the process shown in FIG. It is an enlarged view which shows notionally the behavior of the fusion-bonding material in the process from FIG. 14 to FIG. It is an enlarged view which shows notionally the behavior of the fusion-bonding material in the process from FIG. 14 to FIG. FIG. 16 is a diagram conceptually showing the behavior of a molten bonding material in the process from FIG. 14 to FIG. 15 when the ring varistor shown in FIGS. FIG. 19 is an enlarged partial cross-sectional view taken along line 19-19 in FIG. 18. It is a 20-20 line expanded partial sectional view of FIG. It is a figure which shows the state after a fusion | melting joining material has spread | diffused, and is an expanded partial sectional view in the same cross-sectional position as FIG. It is a figure which shows the state after a fusion | melting joining material has spread | diffused, and is an expanded partial sectional view in the same cross-sectional position as FIG. FIG. 16 is a diagram conceptually showing the behavior of the melt-bonded material in the process from FIG. 14 to FIG. 15 when the ring varistor shown in FIGS. 7 and 8 is manufactured, and is a diagram in plan view of the varistor element. FIG. 24 is an enlarged partial sectional view taken along line 24-24 of FIG. It is a figure which shows the state after a fusion | melting joining material diffused from the state of FIG. 24, and is an expanded partial sectional view in the same cross-sectional position as FIG. It is a top view which shows the arrangement | positioning state of the varistor element and tab in the case of using the tab joining method by a soldering iron. It is a 27-27 line expanded partial sectional view of Drawing 26, and is a figure showing the joining method using a soldering iron. It is a figure which shows the conventional soldering method. It is an expanded partial sectional view of the ring varistor shown in FIG.

Explanation of symbols

21-23 Bonding material
4 Ring Varistor 42-44 Electrode 51-53 Tab 511-531 Notch

Claims (10)

A ring varistor for a motor including a varistor element and a tab,
The varistor element has an electrode on at least one surface of a ring-shaped varistor element,
The tab is made of a thin metal plate and has a through slit or a through hole, and is joined to the electrode of the varistor element by a joining material supplied into the through slit or the through hole,
The bonding material is attached so as not to rise higher than the surface of the tab,
The surface of the tab is a joining surface joined in a facing state to the surface of the riser extending in the rotational diameter direction from the commutator piece of the motor.
Ring varistor.   The ring varistor according to claim 1, wherein the tab is mainly composed of copper.   3. The ring varistor according to claim 1, wherein an inner end portion of the tab is bent along an inner peripheral surface of a center hole provided in the varistor element body. 4.   4. The ring varistor according to claim 1, wherein an outer end portion of the tab protrudes outside the varistor element body. 5.   5. The ring varistor according to claim 1, wherein the bonding material is solder or a brazing material that melts at a low temperature. A method of manufacturing a ring varistor according to any one of claims 1 to 5 ,
A tab having a notch in the surface is disposed on the electrode of the varistor element having an electrode on one surface, and a predetermined amount of molten bonding material is supplied to the notch at a distance from the surface of the tab, Joining the tab to the electrode;
Including steps,
The molten bonding material is supplied so as not to rise higher than the surface of the tab.
Manufacturing method of ring varistor.   The method for manufacturing a ring varistor according to claim 6, comprising at least a step of preheating the surface of the electrode. The manufacturing method according to claim 6 or 7,
Supply solid solder with a predetermined volume to the heating part,
In the heating unit, the supplied solid solder is melted to obtain a predetermined amount of molten solder.
A method of manufacturing a solder ring varistor including a process.   9. The method for manufacturing a ring varistor according to claim 6, comprising a step of dripping the molten solder onto the electrode surface. A motor having a noise absorbing element, a commutator piece, and an armature,
The noise absorbing element is a ring varistor according to any one of claims 1 to 5,
The armature winding is connected to the riser of the commutator piece,
The varistor constituting the noise absorbing element is joined in a state where the joint surface of the tab faces the surface of the riser opposite to the surface facing the armature,
motor.