JP2008282717A - Protector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protector which has little variations in manufacturing and is superior in precision. <P>SOLUTION: The protector comprises a fixed plate 2 having a rising portion 24 and a cut-out portion 22 formed on a welding part 20 and a movable plate 4 having a bent portion positioned at the welding part 20. By engaging the cut-out portion 22 of the fixed plate 2 with the bent portion of the movable plate 4, the positioning precision of the both is improved, and variations in performance of the protector can be suppressed. Furthermore, the rising portion 24 provided in the fixed plate 2 is utilized as a fulcrum at the reversing of a bimetal disk. As a result, displacement amount of a movable contact 6 becomes large and it is prevented that the bimetal disk 3 is reversed, and the contacts becomes rapidly from an open state to a closed state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a protector that opens a circuit by a bimetal when an abnormal temperature or excess current is reached, and more particularly to a motor protector.

  FIG. 7 is a schematic cross-sectional view showing an internal configuration of a conventional protector. A conventional protector includes a metal can 1 that provides a space for accommodating an open / close switch therein, a fixed plate 2 (lower plate), a bimetal disc 3 that performs a snap action operation at a selected temperature, and a bimetal disc. The movable plate (movable arm) 4 that is displaced by the reversing operation of the movable plate 4, the fixed seat 5 (header) that seals the opening of the can 1, the movable contact 6 attached to the end of the movable plate 4, and the fixed plate 2 A fixed contact 7 that contacts or separates from the movable contact 6, a sealing material 8 made of epoxy or the like, and a lead terminal 9 for connection to an external circuit.

  Next, the manufacturing process of the conventional protector will be described with reference to FIGS. 8A and 8B. 8A, the movable plate 4 (movable arm) having the movable contact 6 is assembled to the fixed plate 2 by welding.

  In Step 2 of FIG. 8A, the fixed plate 2 can be fixed by temporarily mounting the fixed seat 5 and the fixed contact 7 using the A part of the fixed plate 2. At this time, the fixed contact 7 is pressed against the fixed seat 5 by the spring force of the movable contact 6. 8A, the fixed contact 7 is fixed to the fixed seat 5 with an adhesive such as epoxy.

  Next, in Step 4 of FIG. 8B, when the adhesive is dried and the fixed contact 7 is bonded to the fixed seat 5, the electric wire 9 is connected to the terminal 10. In step 5 of FIG. 8B, the bimetal disk 3 is inserted between the movable plate 4 and the fixed plate 2. Further, the spring force of the movable contact 6 is adjusted in order to perform an appropriate operation.

  Finally, as shown in FIG. 7, the assembly part shown in Step 5 of FIG. 8B whose operation has been adjusted is inserted into the can 1, the opening of the can 1 is sealed with the sealing material 8, and the sealing material 8 is dry.

  Many applications related to motor protectors have been proposed. For example, Patent Document 1 discloses a protector that can delay the return time according to the state of the electric compressor. A switch including a bimetal disk for opening and closing a current path between the two terminals, an internal space having at least one open surface, an upper base accommodating the switch in the internal space, and each of the PTC and PTC And a lower base including a terminal for a static thermistor that is electrically connected to the electrode surface. When the lower base is mounted there to close the interior space of the upper base, the PCT is connected in parallel to the switch.

JP 2005-98206 A

  Conventional protectors are used in motors such as air conditioners and refrigeration systems, and are adapted to the electrical and thermal characteristics of the motor so that the protectors do not operate during steady operation when the motor is not abnormal. The lead terminals 9a and 9b shown in FIG. 7 are connected in the motor wiring system, and the current input from the lead terminal 9a during steady motor operation is the fixed plate 2, the fixed contact 7, the movable contact 6, and the movable plate. 4 is output to the lead terminal 9b. Or it is used in the opposite polarity.

  When an abnormality such as an overload occurs, abnormal heat generation such as a motor coil is transmitted to the bimetal 3 via the can 1, the fixed plate 2 and the movable plate 4, or an abnormal current flowing to the motor or the like at the time of the abnormality. When the fixed plate 2 and the movable plate 4 generate heat and the bimetal disk 3 installed under the movable plate 4 senses the heat and reaches a preset reversal temperature, the bimetal disk 3 performs a reversal operation. . The reversing operation of the bimetal disk 3 lifts the protrusions 4a and 4b of the movable plate 4 with the protrusion 2a of the fixed plate 2 as a fulcrum, and separates the movable contact 6 and the fixed contact 7 to supply power to the motor and the like. Cut off. The movable contact 6 and the fixed contact 7 can be kept open and closed by reversing the bimetal disk 3, so that components such as a motor can be kept below the damaging temperature and can be protected from burning.

  FIG. 9 is a diagram for explaining a problem that occurs in the manufacturing process of the conventional protector. In the process of manufacturing the conventional protector, the movable plate 4 is fixed to the fixed plate 2 by welding as in step 1 of FIG. 8A. At this time, the relative position of the fixed plate 2 and the movable plate 4 could not be accurately positioned. For example, as shown in FIG. 9, the positions in the directions of arrows a, c, and d can be determined by abutting the fixed plate 2 and the movable plate 4 using a jig. However, the displacement of the movable plate 4 in the direction of the arrow b could not be prevented. Since this step is left to the operator's work accuracy, the assembly position of the fixed plate 2 and the movable plate 4 is not stable, and the performance of the protector may vary.

  Further, in step 5 shown in FIG. 8B (e), the operator lifts the movable plate 4 in order to insert the bimetal disk 3 into the lower portion of the movable plate 4. As a result, the spring force with which the movable contact 6 presses against the fixed contact 7 may be reduced. To compensate for this, in the same step, the spring force adjusting portion shown in FIG. In addition, adjustment of the spring force and the position of the protrusions 4a and 4b of the movable plate 4 are adjusted. Even in this process, the dependence of the worker on the work accuracy is high, and the yield rate of the manufactured protector varies depending on the worker. Further, when the bimetal disc 3 is inserted into the lower portion of the movable plate 4, the movable contact 6 is lifted using a jig shaped like a spatula, which may cause scratches and dirt on the contact surface, resulting in poor product resistance and operation. There was a risk of causing poor durability. Furthermore, when the bimetal disc 3 is inserted into the lower portion of the movable plate 4, the bimetal disc 3 may be caught inside the flange around the portion B of the fixed plate 2 shown in FIG. 9, causing abnormal operation.

  FIG. 10 is a diagram for explaining a problem relating to the operation of the conventional protector. In the protector, when the motor or the like generates heat or an excessive current flows and becomes abnormal, the movable contact 6 and the fixed contact 7 open and close. When the bimetal disk 3 is reversed, the protrusion 2a of the fixed plate 2 is used as a fulcrum, the protrusions 4a and 4b of the movable plate 4 are lifted by the peripheral edge of the bimetal disk 3 serving as an action point, and the movable plate 4 bends to move The contact 6 and the fixed contact 7 are separated. At this time, it is necessary to adjust the distance between the protrusion 2 a of the fixed plate 2 and the protrusions 4 a and 4 b of the movable plate 4 to an appropriate state with respect to the amount of reverse operation displacement of the bimetal disk 3. If this interval is not appropriate, the interval between the movable contact 6 and the fixed contact 7 becomes narrow in the initiating region of the bimetal disk 3 until the contact is closed again after the movable contact 6 and the fixed contact 7 are separated. Occasionally, the movable contact 6 and the fixed contact 7 may be closed before the bimetal disk 3 is reversed. When such a phenomenon occurs, the movable contact 6 and the fixed contact 7 of the protector wear rapidly, and eventually the contact welded state is lost in a short period of time, and the function as the protector is lost. It can no longer be protected.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a protector with low manufacturing variation and high operation accuracy. Furthermore, an object of the present invention is to provide a protector that can accurately position the movable arm when the movable arm is welded to the fixed plate in the manufacturing process.

  The protector according to the present invention has a disc-shaped outer shape, includes a bimetal disk having an opening formed in the center thereof, includes a movable contact at one end, and includes a first weld at the other end, Furthermore, a movable arm made of a conductive metal having an opening formed between one end and the other end, a protrusion inserted into each opening of the bimetal disk and the movable arm, and a first of the movable arm. A fixed plate made of a conductive metal for fixing a bimetal disk and a movable arm on the bimetal disk, and a bimetal disk mounted on the fixed plate. A movable contact that is displaced in response to the movement of the movable contact, and a fixed contact that is in contact with or separated from the movable contact, wherein a first positioning portion is formed on the first weld of the movable arm, and the second weld In A second positioning portion for engagement with the first positioning portion is formed, the first and second weld with the first and second positioning portion is positioned is welded.

  Preferably, the first positioning part is a bent part or a notch part, and the second positioning part is a notch part or a bent part engaged with the bent part or the notch part. More preferably, an abutting portion is formed between the protrusion of the fixing plate and the second welded portion so that the periphery of the bimetal disc abuts when the bimetal disc performs a reversing operation. For example, the contact portion is formed by cutting and raising the second welded portion of the fixed plate.

  Preferably, a bent portion is formed along the longitudinal direction on the opposite side surfaces of the fixed plate, and a notch is formed at a position corresponding to the bimetal disk of the bent portion. The protector further includes a can that substantially seals the fixed plate, the bimetal disk and the movable arm inside. In this case, the first terminal portion electrically connected to the fixed plate and the second terminal portion electrically connected to the fixed contact may be exposed from a part of the can.

  In the protector assembling method according to the present invention, a bimetal disk and a movable arm are mounted on a fixed plate made of a conductive metal, and the movable contact of the movable arm is brought into contact with or separated from the fixed contact according to the operation of the bimetal disk. A protrusion for insertion into the opening of the bimetal disc and the movable arm, a first engaging portion is formed in a region where the welded portion of the movable arm is welded, and a fixed contact is provided via an insulating member. An attached fixed plate is prepared, a bimetal disk is mounted on the fixed plate so that the protruding portion of the fixed plate is inserted into the opening, the protruding portion of the fixed plate is inserted into the opening of the movable arm, and Positioning the movable arm on the fixed plate so that the second engaging portion formed on the welded portion of the movable arm is engaged with the first engaging portion of the fixed plate; 1 and in a second state in which the engaging portion is positioned to weld the welding portion of the movable arm to the weld region of the fixed plate.

  According to the protector of the present invention, the positioning accuracy of the movable arm is improved, and variations in manufacturing can be suppressed. Further, since the movable arm operates normally based on the reversing operation of the bimetal disk, the contact opening / closing performance is stabilized and abnormal operation can be prevented.

  The best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Fig.1 (a) is a top view of the fixing plate which is the principal part of the protector based on a present Example, FIG.1 (b) is the sectional view on the AA line of Fig.1 (a), FIG.1 (c) is fixing. It is a perspective view of a board. FIG. 2 is a plan view and a side view showing the movable plate of the protector according to the present embodiment.

  The fixed plate 2 is obtained by processing a plate made of a conductive metal. A welded portion 20 for welding the movable plate is formed at one end, and a terminal portion 10 protruding outside the can is formed at the other end. ing. A conical projection 2a having a flat surface is formed between the welded portion 20 and the terminal portion 10. The protrusion 2a is inserted into circular openings 3a and 4c formed in the bimetal disk and the movable plate, and supports the bimetal disk and the movable plate. Further, a flange 21 is formed on the opposite side surfaces of the fixed plate 2 by bending the plate substantially vertically. The flange 21 plays a role of reinforcing the strength of the fixing plate.

  In the present embodiment, the welded portion 20 of the fixed plate may include a flat surface, and preferably include a welding spot. A cutout portion 22 having a constant width is formed in the welded portion 20. The notch 22 is formed, for example, by cutting and raising the fixing plate 2. Of course, the notch 22 may be formed by other methods.

  Further, a cut-and-raised part 24 is formed on the side of the fixed plate 2 facing the notch part 22. The cut-and-raised part 24 slightly extends the surface of the welded part 20 toward the protrusion 2a, and abuts the periphery of the bimetal disk when the bimetal disk described later is inverted. The cut-and-raised portion 24 is preferably formed by forming a slit in the vertical portion forming the welded portion 20 and lifting it. Of course, the cut and raised portion 24 may be formed by other methods.

  Further, a flange notch 26 is formed on the flange 21 of the fixed plate 2 at a position corresponding to the bimetal disk, that is, a position facing the protrusion 2 a of the fixed plate 2. The notch 26 prevents interference with the periphery of the bimetal disk when the bimetal disk is reversed.

  A bent portion 30 (see FIG. 2) formed at the end of the movable plate 4 is inserted into the notch 22 and is engaged with each other, so that the two-dimensional direction of the movable plate 4, that is, X Positioning in the -Y direction is performed. Thereby, when welding the movable plate 4 to the fixed plate 2, the positional accuracy of the movable plate can be improved without depending on the jig or the experience of the operator. In addition, it is desirable to facilitate insertion by providing a taper in the cutout portion 22 and the bent portion 30 of both parts in consideration of workability.

  Furthermore, when the end of the movable plate 4 is welded to the fixed plate 2, the spring force of the movable plate 4 and the position of the semicircular projection 4a formed on the movable plate 4 are set to an appropriate state. For this reason, the process of adjusting the spring force by the manual work performed by the conventional process becomes unnecessary. Therefore, any worker can manufacture a protector having the same performance, and the variation in the performance of the protector can be suppressed.

  The flange notch 26 formed in the flange 21 of the fixed plate 2 is such that when the bimetal disc 3 is supported by the protrusion 2a of the fixed plate 2 and the bimetal disc 3 performs a snap action operation at a selected temperature, the bimetallic disc 3 It can prevent that the periphery of 3 contacts a flange and the snap action operation | movement of the bimetal disc 3 is suppressed.

  FIG. 3 is a diagram illustrating a manufacturing process of the protector according to the present embodiment. In step 1 of FIG. 3, the fixed seat 5 and the fixed contact 7 are fixed to the fixed plate 2. As described above, the notch portion 22 and the cut-and-raised portion 24 are formed at the end portion of the fixed plate 2. The fixed seat 5 is made of an electrically insulating material, for example, ceramic, and is fixed to a predetermined position of the fixed plate 2. Fixed contact 7 includes a silver alloy surface in a region in contact with movable contact 6 and a terminal portion 7a extending therefrom and connected to an external circuit.

  Next, in step 2 of FIG. 3, the protrusion 2 a of the fixing plate 2 is inserted into the opening 3 a of the bimetal disc 3, and the bimetal disc 3 is supported on the fixing plate 2. Next, in step 3 of FIG. 3, the protrusion 2 a of the fixed plate 2 is inserted into the opening 4 c of the movable plate 4, and the bent portion 30 of the movable plate 4 is positioned at the notch 22 of the fixed plate 2. And the bending part 30 and the notch part 22 of the movable plate 3 are welded. At this time, the movable contact 6 of the movable plate 4 has a constant contact pressure with respect to the fixed contact 7.

  FIG. 4 is a diagram for explaining the operation of the protector according to the embodiment of the present invention. In the conventional protector, in response to the snap action operation of the bimetal disk 3, the movable plate 4 is displaced with the central protrusion 2a as a fulcrum and the protrusion 4a as an action point.

  On the other hand, in the protector according to the present embodiment, the bent portion 30 welded to the cut-and-raised portion 24 of the movable plate 4 serves as a fulcrum, and is displaced with the protruding portion 4a as the action point. When the bimetal disk 3 is reversed, one of its peripheral edges comes into contact with the back surface of the raised portion 24, so that the other peripheral edge of the bimetal disk 3 is lifted high. As shown by the broken line in FIG. It is far away from the fixed contact 7.

  On the other hand, when the bimetal disc 3 returns, the periphery of the bimetal disc 3 is not in contact with the vicinity of the fulcrum of the movable plate 4 but is in contact with the cut and raised portion 24. For this reason, even if the bimetal disc 3 is slightly displaced downward due to creep, the protrusion 4a only moves slightly downward, and the movable contact 6 can be prevented from chattering with the fixed contact 7.

  FIG. 5 is a diagram showing various modifications of the fixed plate 2. The fixed plate 2 shown in FIG. 5A is for fixing another flat member 40 to the cut and raised portion 24 instead of forming the cut and raised from the side surface of the fixed plate 2. The fixing plate 2 shown in FIG. 5 (b) is formed by bending inward from both sides of the side surface of the fixing plate 2 to form a pair of cut and raised portions 42. The notch 22 of the fixed plate 2 shown in FIG. 5C forms a rectangular groove 44. The notch 22 of the fixed plate 2 shown in FIG. 5 (d) forms a pair of slits 46 extending from both sides to the inside.

  FIG. 6 is a diagram illustrating a modification example of the movable plate 4. The movable plate 4 shown in FIG. 6A has a clip-shaped bent portion 50 in which a part of its end is bent in a direction substantially parallel to the movable plate 4. The movable plate 4 shown in FIG. 6B has a bent portion 52 that is bent in a direction in which the entire end portion thereof is substantially parallel to the movable plate 4. The movable plate 4 shown in FIG. 6C has a bending member 54 that is bent so that the entire end thereof is curved. The movable plate 4 shown in FIG. 6D has a pair of bent portions 56 bent at right angles at both ends of the end portion. The shape and size of the bent portion of the movable plate 4 are selected so as to match the shape and size of the notch portion of the fixed plate 2.

  According to the protector of the embodiment of the present invention, the notch 22 is provided in the fixed plate 2 and the bent portion 30 is provided in the movable plate 4, so that it is necessary to manually determine the assembly position of the parts when welding. Productivity is improved. Thereby, the variation in the performance of a protector can be suppressed and stable production can be performed.

  Moreover, by providing the cut-and-raised portion 24 in the fixed plate 2, the risk of dimensional variation due to the welding process can be reduced to half. Furthermore, by providing a cut-and-raised portion 24 in the fixed plate 2 and changing the action point that moves when the bimetal disk 3 is reversed from two points on the outer periphery to one point on the outer periphery, the contact opening / closing performance of the product is stabilized. The inspection process for preventing abnormal operation that may occur in the market can be reduced.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments according to the present invention, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible.

  The protector according to the present invention can be used as an external type of an electric compressor shell. In particular, the present invention can be applied to a large output compressor in which an internal protector is used.

It is a figure which shows the fixing plate of the protector which concerns on a present Example. It is a figure which shows the movable plate of the protector which concerns on a present Example. It is a figure which shows the manufacturing process of the protector which concerns on a present Example. It is a figure explaining operation | movement of the protector which concerns on a present Example. It is a figure which shows the example of a change of a stationary plate. It is a figure which shows the example of a change of a movable plate. It is a figure which shows the conventional protector. It is a figure which shows process 1, 2, and 3 of the manufacturing process of the conventional protector. It is a figure which shows process 4 and 5 of the manufacturing process of the conventional protector. It is a figure explaining the problem of the manufacturing process of the conventional protector. It is a figure explaining the problem of operation | movement of the conventional protector.

Explanation of symbols

1: Can 2: Fixed plate 3: Bimetal disk 3a: Opening 4: Movable plate 4a, 4b: Protrusion 4c: Opening 5: Fixed seat 6: Movable contact 7: Fixed contact 7a: Terminal 8: Sealing material 9: Terminal 10: Terminal 20: Welded portion 22: Notched portion 24: Cut-and-raised portion 26: Notched portion 30: Bent portion 40: Flat member 42: Cut-raised portion 44: Groove 46: Slit 50 to 56: Bent portion

Claims (12)

A bimetallic disc having a disc-shaped outer shape and having an opening formed in the center thereof;
Movable contact made of a conductive metal that includes a movable contact at one end, a first weld at the other end, and an opening formed between one end and the other end Arm,
In order to fix the bimetal disk and the movable arm on the bimetal disk, including a protrusion inserted into each opening of the bimetal disk and the movable arm and a second welded portion welded to the first weld of the movable arm A fixing plate made of a conductive metal of
A fixed contact mounted on the fixed plate and contacting or spaced apart from the movable contact that is displaced in response to the operation of a bimetal disk;
A first positioning portion is formed on the first welding portion of the movable arm, and a second positioning portion that engages with the first positioning portion is formed on the second welding portion. The first and second welds are welded in a state where the second positioning portion is positioned.
Protector. The protector according to claim 1, wherein the first positioning part is a bent part or a notch part, and the second positioning part is a notch part or a bent part engaged with the bent part or the notch part. The contact part which the periphery of a bimetal disk contact | abuts is formed between the said projection part of the said fixing plate, and the said 2nd welding part when a bimetal disk reverse | inverts operation | movement. The protector described in 1. The protector according to claim 3, wherein the contact portion is formed by cutting and raising the second welded portion of the fixed plate. The bent side is formed in the side surface which the said fixed plate opposes along a longitudinal direction, The notch part is formed in the position corresponding to the said bimetal disc of the said bent part. The protector described in one. The protector according to any one of claims 1 to 5, further comprising a can that substantially seals the fixed plate, the bimetal disk, and the movable arm inside. The protector further includes a first terminal portion electrically connected to the fixed plate, and a second terminal portion electrically connected to the fixed contact, wherein the first and second terminal portions are: The protector according to claim 6, wherein the protector is exposed from a part of the can. A method of assembling a protector, wherein a bimetal disk and a movable arm are attached on a fixed plate made of a conductive metal, and the movable contact of the movable arm is brought into contact with or separated from the fixed contact according to the operation of the bimetal disk,
The bimetal disc and the protrusion for insertion into the opening of the movable arm are formed, the first engagement portion is formed in the region where the welded portion of the movable arm is welded, and the fixed contact is attached via the insulating member Prepare the board,
A bimetal disc is mounted on the fixed plate so that the protrusion of the fixed plate is inserted into the opening,
The protrusion of the fixed plate is inserted into the opening of the movable arm, and the second engagement portion formed on the welded portion of the movable arm is engaged with the first engagement portion of the fixed plate. Positioning the movable arm on the fixed plate;
Welding the welded portion of the movable arm to the welding region of the fixed plate with the first and second engaging portions positioned;
Assembling method of the protector. 9. The protector assembling method according to claim 8, wherein the fixing plate further includes an abutting portion between the welded area and the protruding portion, which abuts the periphery of the bimetallic disc when the bimetallic disc is inverted. The assembly method according to claim 9, wherein the contact portion is formed by cutting and raising the fixing plate. The assembling method according to claim 8, wherein a bent portion is formed along a longitudinal direction on opposite side surfaces of the fixing plate, and a notch portion is formed at a position corresponding to the bimetal disk of the bent portion. . The assembly method according to any one of claims 8 to 11, further comprising a step of sealing the fixed plate, the bimetal disk, and the movable arm in a can.

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