WO2023277191A1 - Thermomotive overload relay - Google Patents

Abstract

A bimetal (21) bends when heated. When the bimetal bends, a shifter (22) is displaced by being pushed by the bimetal. A lever (23) is pivotally supported on a pivot shaft (63), and pivots by being pushed by the shifter when the shifter is displaced. When the lever pivots, a reversing mechanism is pushed by the lever from a position thereof radially outside a position thereof that is pushed by the shifter, thereby reversing a contact.

Description

thermal overload relay

The present invention relates to a thermal overload relay.

When overcurrent continues to flow, a thermal overload relay (thermal relay) trips by bending the bimetal due to heat, and overloads the main circuit by shutting off the magnetic contactor or circuit breaker for wiring. protect from In the thermal overload relay, as shown in Patent Document 1, when the bimetal is heated and bent, the shifter is pushed to operate the reversing mechanism, resulting in a trip state.

JP 2014-107023 A

Thermal overload relays include a 1E (single element) type that protects against overload and a 2E (two elements) type that protects against overload and loss of phase. The 1E type generally has a two-element structure with bimetals in the two phases of U and W, and the 2E type has a three-element structure with bimetals in the three phases of U, V, and W. Here, since the number of elements in the two-element structure is smaller than that in the three-element structure, the amount of displacement of the shifter is correspondingly reduced.
The thermal overload relay is assembled by assembling together the shifter and the lever that rotates when pushed by the shifter. A step of engaging the bimetal is performed. However, the procedure for assembling the shifter and lever was complicated, and it was difficult to align the shifter with the free end of the bimetal and align the lever with the compensating bimetal.

An object of the present invention is to provide a thermal overload relay with a two-element structure that can amplify the displacement of a shifter and transmit it to a reversing mechanism to protect against overload. Another object of the present invention is to provide a thermal overload relay capable of simplifying assembly and realizing automatic assembly.

A thermal overload relay according to one aspect of the present invention is a thermal overload relay with a two-element structure that protects against overload. a lever rotatably supported by a support shaft and rotated by being pushed by the shifter when the shifter is displaced; a reversing mechanism for reversing the contact by being pushed from a position radially outside the pushed position.

Further, a thermal overload relay according to an aspect of the present invention includes a plurality of partition walls provided inside a case, a plurality of bimetals arranged between the plurality of partition walls and curved when heated, a plurality of When the bimetal is bent, the shifter is pushed by the bimetal to be displaced, the lever is pushed by the shifter to rotate, and the lever is pushed to rotate. a reversing mechanism for reversing the contacts, wherein a plurality of elongated holes formed longitudinally extending in the displacement direction of the shifter; The elongated holes are slidably fitted, and a plurality of projections that guide the displacement of the shifter. and a shifter drop-off preventing portion for preventing drop-off of the shifter.

According to the thermal overload relay of the present invention, when the bimetal is bent, the reversing mechanism is pushed from a position radially outside the position of the lever pushed by the shifter, thereby amplifying the displacement of the shifter. It can be transmitted to the reversing mechanism.
Further, according to the thermal overload relay of the present invention, by providing the shifter drop-off preventing portion for preventing the shifter from dropping out of the case, it is possible to simplify the assembly and realize automatic assembly. .

It is a figure which shows the thermal overload relay of 1st Embodiment in the state which removed the cover. It is a figure which shows the shifter and lever of 1st Embodiment. It is a figure which shows the case of 1st Embodiment. It is a figure which shows the shifter of 1st Embodiment. It is a perspective view which shows the lever of 1st Embodiment. It is a projection view which shows the lever of 1st Embodiment. It is a figure explaining operation|movement of the shifter of 1st Embodiment, and a lever. It is a figure which shows a comparative example. It is a figure which shows the thermal overload relay of 2nd Embodiment in the state which removed the cover. It is a perspective view which shows the thermal overload relay of 2nd Embodiment. FIG. 11 shows a pull shifter of a second embodiment; It is a perspective view which shows the differential lever of 2nd Embodiment. It is a figure which shows the structure of the differential lever of 2nd Embodiment. It is a figure which shows the push shifter of 2nd Embodiment, a pull shifter, and a differential lever. FIG. 15 is a cross-sectional view taken along line BB of FIG. 14; It is a figure which shows the state which attached the pulling shifter of 2nd Embodiment to the case. It is a figure which shows the state which attached the push shifter of 2nd Embodiment to the case. It is a figure which shows the state which attached the differential lever of 2nd Embodiment to the case.

Hereinafter, embodiments of the present invention will be described based on the drawings. Note that each drawing is schematic and may differ from the actual one. Moreover, the following embodiments are intended to exemplify devices and methods for embodying the technical idea of the present invention, and are not intended to limit the configurations to those described below. That is, the technical idea of the present invention can be modified in various ways within the technical scope described in the claims.

<<1st Embodiment>>
"composition"
In the following description, the three mutually orthogonal directions are referred to as the vertical direction, the width direction, and the depth direction for convenience.
FIG. 1 is a diagram showing a thermal overload relay according to a first embodiment of the invention.
The thermal overload relay 11, also called a thermal relay, trips when an overcurrent continues to flow, and protects the main circuit from overload by shutting off an electromagnetic contactor (not shown). The thermal overload relay 11 has a 1E (single-element) type that protects against overload and a 2E (two-element) type that protects against overload and open phase. Here, the 1E type is used. The figure shows the inside of the case 12 of the thermal overload relay 11 viewed from the other side in the vertical direction with the cover (not shown) removed.

Inside the case 12, a bimetal 21, a shifter 22, a lever 23, a reversing mechanism 24, and a reset rod 25 are provided. The thermal overload relay 11 has a two-element structure having a bimetal 21 in two phases of U and W. As shown in FIG.
The bimetal 21 extends in the depth direction and is formed in a plate shape along the vertical and depth directions, with the front side in the depth direction serving as a fixed end and the depth side serving as a free end. The bimetal 21 is connected to the main terminal at the front side in the depth direction, and is joined to one end of the heater 26 at the back side in the depth direction. The heater 26 is wound around the bimetal 21, and the other end is joined to the connection terminal 27 on the front side in the depth direction. The connection terminal 27 is connected to an electromagnetic contactor (not shown). The bimetal 21 is normally linear, but when overloaded, the free end bends toward the other side in the width direction and pushes the shifter 22 .

The shifter 22 is an insulator, formed in the shape of a flat plate along the width direction and the length direction, and supported by the case 12 so as to move back and forth in the width direction. The shifter 22 engages with the free end of the bimetal 21 and is normally positioned on one side in the width direction. However, in an overloaded state, the bimetal 21 bends and shifts to the other side in the width direction. Displace. The shifter 22 is formed by coating the surface of the base material with a solid lubricant in order to reduce the friction coefficient of the surface.
The lever 23 is integrally molded of electrically insulating resin, extends vertically, amplifies the amount of displacement of the shifter 22 and transmits it to the reversing mechanism 24 when an overload state is detected.

The reversing mechanism 24 is a mechanism that reverses the contacts when an overload is detected, that is, closes the a-contact and opens the b-contact. , a leaf spring 35 and an interlocking plate 36 . Since the reversing mechanism 24 is not a main component of the embodiment, its outline will be described.
The compensating bimetal 31 extends in the depth direction and is formed in a flat plate shape along the depth direction and the vertical direction. doing.
The release lever 32 extends in the depth direction, is formed in a plate shape along the depth direction and the vertical direction, and is rotatably supported by a support shaft along the vertical direction. in contact.
The tension spring 33 pulls the movable plate 34 toward the depth side.

The movable plate 34 has a flat plate shape along the depth direction and the vertical direction, and the front side in the depth direction can be displaced in the width direction with the back side in the depth direction as a fulcrum. The upright position of the movable plate 34 is a dead point, and when a force acts on one side or the other side in the width direction, the tensile force of the tension spring 33 tilts the movable plate 34 to one side or the other side in the width direction. Normally, it is tilted to one side in the width direction, but when it becomes overloaded, it is pushed by the release lever 32 via the compensating bimetal 31 and tilted to the other side in the width direction. The movable plate 34 is connected to one of the auxiliary terminals on the far side in the depth direction, and a movable contact is formed on the front side in the depth direction.

The plate spring 35 extends in the depth direction and has a flat plate shape along the depth direction and the vertical direction. A contact is formed. Normally, the movable contact of the movable plate 34 is separated from the fixed contact of the leaf spring 35. However, in an overload state, the movable plate 34 tilts to the other side in the width direction, thereby fixing the leaf spring 35. A movable contact of the movable plate 34 comes into contact with the contact. The fixed contact and the movable contact form an a-contact, and when the a-contact is closed, a trip state occurs.
The interlocking plate 36 is formed in a plate shape along the width direction and the depth direction, is rotatably supported by a support shaft along the length direction, and is engaged with the movable plate 34 on the back side in the depth direction. . The interlocking plate 36 rotates in conjunction with the movable plate 34 to open and close the contacts on the back side of the interlocking plate 36 not shown in the drawing. That is, the movable contact is normally in contact with the fixed contact, but when the overload condition occurs, the interlocking plate 36 rotates to separate the movable contact from the fixed contact. The fixed contact and the movable contact form a b-contact, and when the b-contact opens, a trip state occurs.

The reset rod 25 is an operator for recovering from the tripped state, is formed in a substantially cylindrical shape with the depth direction as the axial direction, and is arranged on the other side of the case 12 in the vertical direction and the other side in the width direction. It is The reset rod 25 is supported by the case 12 so as to be displaceable in the depth direction and rotatable about the axis, and is biased forward in the depth direction by a plate spring 47 extending in the vertical direction. The reset rod 25 has an initial position, a manual reset position and an automatic reset position. The initial position is a position where the front side in the depth direction protrudes from the case 12 . The manual reset position is a position that is pushed farther in the depth direction from the initial position. The automatic reset position is a position where the position in the depth direction is held by being pushed from the initial position to the depth side in the depth direction and rotated clockwise by about 90 degrees when viewed from the front side in the depth direction.

When the reset rod 25 is pushed backward in the depth direction in a tripped state, the plate spring 35 and the movable plate 34 are pushed to one side in the width direction by the end portion on the depth direction, thereby causing an overload state. is eliminated, the a-contact is opened again and the b-contact is closed. On the other hand, when the reset rod 25 is pushed to the depth side in the tripped state and is rotated clockwise by about 90 degrees as viewed from the front side in the depth direction, the reset rod 25 moves to the depth direction position. is retained. Since the plate spring 35 and the movable plate 34 are pushed to one side in the width direction by the end on the far side in the depth direction, when the overload state is eliminated, the a-contact is automatically opened again and the b-contact is opened. close up.

Next, the structures of the shifter 22 and the lever 23 will be described.
FIG. 2 is a diagram showing a shifter and a lever.
Here, the case 12 is shown viewed from the other side in the vertical direction, one side in the width direction, and the back side in the depth direction.
FIG. 3 is a diagram showing a case.
Here, the case 12 is shown viewed from the other side in the vertical direction, one side in the width direction, and the back side in the depth direction. Partition walls 41 to 43 and a girder plate 44 are formed inside the case 12 .

The partition walls 41 to 43 are arranged in order from one side in the width direction to the other side, extend in the depth direction, and are formed in a plate shape along the depth direction and the longitudinal direction. A U-phase bimetal 21 and a connection terminal 27 are arranged on one side of the partition wall 41 in the width direction. A V-phase connection terminal 27 is arranged between the partition 41 and the partition 42 . A W-phase bimetal 21 and a connection terminal 27 are arranged between the partition 42 and the partition 43 . A reversing mechanism 24 is arranged on the other side of the partition wall 43 in the width direction. Each of the partition walls 41 to 43 has a substantially cylindrical protrusion 45 protruding toward the depth in the depth direction on the other longitudinal side of the end face on the depth side in the depth direction. The protrusions 45 are arranged in a straight line along the width direction. Only the protruding portion 45 of the partition wall 42 protrudes toward the other side in the width direction at the head portion on the far side in the depth direction.

The partition walls 41 to 43 are also formed with a substantially cylindrical projection 45 that protrudes toward the depth side on one side in the lengthwise direction of the end faces on the depth side in the depth direction. Only the protruding portion 45 of the partition wall 42 has a head portion on the far side in the depth direction that protrudes toward the other side in the width direction. The projecting portion 45 provided on one side in the vertical direction is fitted with a shifter when the 1E type or 2E type of the three-element structure having a bimetal also in the V phase is adopted. Therefore, the case 12 is common to the 1E type and 2E type of the three-element structure.
The girder plate 44 is arranged on the far side in the depth direction, extends in the width direction, and is formed in a plate shape along the width direction and the vertical direction. In the girder plate 44, the edge portion on the other side in the width direction and the other side in the longitudinal direction of the partition wall 43 is concaved toward one side in the longitudinal direction and has a substantially U shape when viewed from the depth direction. A groove 46 is formed.

FIG. 4 is a diagram showing a shifter.
The shifter 22 is a substantially square flat plate having long sides in the width direction and short sides in the vertical direction. The shifter 22 is formed with an elongated hole 51 extending in the width direction on one side in the width direction and into which the protrusion 45 of the partition wall 41 is fitted. The shifter 22 has an elongated hole 52 extending in the width direction on the other side in the width direction, into which the protrusion 45 of the partition wall 42 and the protrusion 45 of the partition wall 43 are fitted. The elongated hole 52 has different vertical sizes on one side and the other side in the width direction. It is smaller than the head of the protrusion 45 on the partition wall 42 . The shifter 22 can be displaced along the width direction by fitting the long hole 51 to the protrusion 45 of the partition 41 and fitting the long hole 52 to the protrusion 45 of the partition 42 and the protrusion 45 of the partition 43. becomes. When the projection 45 of the partition wall 42 is on one side of the elongated hole 52 in the width direction, the shifter 22 can be removed. When the protrusion 45 of the partition wall 42 is on the other widthwise side of the elongated hole 52, the head of the protrusion 45 prevents the shifter 22 from being removed.

Engagement pieces 53 to 55 are formed on one side of the shifter 22 in the vertical direction. The engaging piece 53 is arranged on one side in the width direction of the partition wall 41 and protrudes from one side in the vertical direction to one side in the width direction. A free end of the bimetal 21 in the U-phase engages with the tip of the engaging piece 53 facing one side in the width direction. The engaging piece 54 is arranged between the partition wall 41 and the partition wall 42 and protrudes from one side in the vertical direction to one side in the width direction. The engaging piece 55 is arranged on the other side in the width direction of the partition wall 43 and protrudes from one side in the vertical direction toward both the one side and the other side in the width direction. The free end of the bimetal 21 in the W phase engages with the tip of the engaging piece 53 directed to one side in the width direction, and the lever 23 engages with the tip 56 directed to the other side in the width direction.
When the 1E type of the three-element structure is adopted, the free end of the bimetal in the V phase engages with the tip of the engaging piece 54 facing one side in the width direction. Therefore, the shifter 22 is shared with the 1E type of three-element structure.

FIG. 5 is a perspective view showing a lever.
(a) in the figure shows the lever 23 viewed from the other side in the vertical direction, one side in the width direction, and the far side in the depth direction. The state seen from one side in the direction, the other side in the width direction, and the front side in the depth direction.
FIG. 6 is a projection view showing the lever.
(a) in the figure shows a state in which hidden lines are displayed when the lever 23 is viewed from the far side in the depth direction, and (b) in the figure shows a state in which the lever 23 is viewed from the other side in the width direction, (c) in the figure shows the AA section of (b).

A pair of opposed plates 61 and 62 are formed on one side of the lever 23 in the vertical direction. The opposing plates 61 and 62 are formed in a flat plate shape along the vertical direction and the width direction, face each other while being spaced apart in the depth direction, and are connected by a cylindrical support shaft 63 extending in the depth direction. The distance between the facing plates 61 and 62 is slightly larger than the thickness of the girder plate 44 and the diameter of the support shaft 63 is slightly smaller than the groove 46 . The lever 23 is rotatably supported by the support shaft 63 with respect to the case 12 by fitting the support shaft 63 into the recessed groove 46 in a state in which the girder plate 44 is sandwiched between the facing plates 61 and 62 . The lever 23 is formed with an end face 64 facing one side in the width direction over approximately half of the other side in the lengthwise direction. The end surface 64 is a flat surface extending in the longitudinal direction and the depth direction, and engages with the tip 56 of the engaging piece 53 of the shifter 22 . The lever 23 has an end surface 65 facing the other side in the width direction on the other side in the vertical direction. The end surface 65 is a curved surface along the depth direction that is convex toward the other side in the width direction, and engages with the free end of the compensating bimetal 31 in the reversing mechanism 24 . As shown in FIG. 6, when viewed from the depth direction, a dotted straight line L1 connecting the center of the support shaft 63 and the position of the end surface 65 that bulges most to the other side in the width direction extends along the vertical direction. extended.

"motion"
Next, main operations of the first embodiment will be described.
FIG. 7 is a diagram for explaining operations of the shifter and the lever.
Here, a state in which the case 12 is viewed from the depth side in the depth direction is shown. Normally, the shifter 22 is positioned on one side in the width direction, and the end surface 65 of the lever 23 is pushed by the compensating bimetal 31 so that the other side in the vertical direction is positioned on the one side in the width direction.
When the shifter 22 is overloaded, the bimetal 21 bends, so that at least one of the engaging piece 53 and the engaging piece 55 is pushed and the shifter 22 is displaced to the other side in the width direction. As a result, the end surface 64 of the lever 23 is pushed by the tip 56 of the engaging piece 55 by displacing the shifter 22 to the other side in the width direction, and the lever 23 rotates counterclockwise when viewed from the back side in the depth direction. , the other side in the longitudinal direction is displaced to the other side in the width direction. As a result, the free end of the compensating bimetal 31 is displaced to the other side in the width direction, so that the reversing mechanism 24 is in a trip state in which the contact a is closed and the contact b is opened.

Then, when the overloaded state is eliminated, the bimetal 21 returns to a straight shape, and the free end side returns to one side in the width direction. Further, when the reset rod 25 is at the manual reset position or the automatic reset position, the reversing mechanism 24 returns to the normal state in which the a-contact is opened and the b-contact is closed. to one side of the As a result, the end surface 65 of the lever 23 is pushed by the compensating bimetal 31 , so that the lever 23 rotates clockwise when viewed from the back side in the depth direction, and the other side in the vertical direction is displaced to the one side in the width direction. As a result, the shifter 22 returns to one side in the depth direction as the engaging piece 55 is pushed by the end surface 64 of the lever 23 .

《Action》
Next, main effects of the first embodiment will be described.
A thermal overload relay 11 having a two-element structure for protecting against overload includes a bimetal 21 , a shifter 22 , a lever 23 and a reversing mechanism 24 . The bimetal 21 bends when heated. The shifter 22 is pushed by the bimetal 21 and displaced when the bimetal 21 is bent. The lever 23 is rotatably supported by the support shaft 63 and is pushed by the shifter 22 to rotate when the shifter 22 is displaced. When the lever 23 rotates, the reversing mechanism 24 is pressed from a position radially outside the position of the lever 23 that is pressed by the shifter 22 , thereby reversing the contact.

Thereby, the lever 23 can amplify the displacement amount of the shifter 22 and transmit it to the reversing mechanism 24 . That is, since the two-element structure has a smaller number of elements than the three-element structure, the amount of displacement of the shifter 22 is correspondingly reduced. Therefore, it is not necessary to review the design of the heater 26 in order to obtain the same amount of displacement with the two-element structure as with the three-element structure. Moreover, it is not necessary to design the heater 26 separately for the two-element structure and the three-element structure, and the heater can be shared. Therefore, an increase in manufacturing cost can be suppressed, and the management of each part in the assembly process can be facilitated. Since the lever 23 is integrally formed with the support shaft 63, an increase in the number of parts is suppressed and the easiness of the assembly work is improved.

The lever 23 adjusts the position of the support shaft 63 serving as the center of rotation, the position pushed by the shifter 22, and the position pushed against the reversing mechanism 24, thereby adjusting the amplification factor of the displacement amount of the shifter 22. For example, when viewed from the depth direction, the closer the position of the support shaft 63 is to the position pushed by the shifter 22, and the further the position pushed by the shifter 22 is from the position to push the reversing mechanism 24, the greater the amplification factor. In this manner, the amplification factor can be arbitrarily adjusted and transmitted to the reversing mechanism 24 . Depending on the amplification factor, the amount of displacement of the compensating bimetal 31 can be made larger than in the case of the three-element structure, so malfunction of the reversing mechanism 24 can be suppressed and reliability can be improved.

When the bimetal 21 is not curved, that is, when the lever 23 is normal, the position of the support shaft 63 serving as the center of rotation and the position of pressing the reversing mechanism 24 when viewed from the axial direction of the support shaft 63 are the same as those of the reversing mechanism 24 . are lined up in the direction perpendicular to the direction in which you press . That is, when viewed from the depth direction, the angle θ formed by the straight line L1 connecting the center of the support shaft 63 and the position of the end face 65 that bulges most toward the other side in the width direction with respect to the vertical direction is made as small as possible. doing. This is because when the lever 23 rotates, the trajectory of the end surface 65 at the position where it bulges most to the other side in the width direction displaces more in the width direction as the angle θ formed by the straight line L1 with respect to the vertical direction decreases. be. Therefore, the track at the position where the reversing mechanism 24 is pushed is most likely to be displaced in the width direction, and the amplification factor of the amount of displacement in the shifter 22 can be increased.

In the shifter 22, the position where the bimetal 21 pushes and the position where the lever 23 is pushed are arranged on a straight line along the displacement direction. In this way, the point of force and the point of action are arranged on a straight line, so that when the shifter 22 is pushed by the bimetal 21, it prevents a clockwise moment from being applied when viewed from the far side in the depth direction. can. Therefore, it is no longer necessary to suppress the moment by weight balance, such as enlarging the shape of the shifter 22 to one side in the vertical direction from the position where it is pushed by the bimetal 21 when viewed from the depth direction. can be realized.
The shifter 22 has a flat plate shape, and the lever 23 rotates in the plane direction of the shifter 22 with the support shaft 63 extending in the direction perpendicular to the plane of the shifter 22 . As a result, it is possible to prevent the thermal overload relay 11 from increasing in size in the depth direction.

Next, a comparative example will be described.
FIG. 8 is a diagram showing a comparative example.
Here, a state in which the case 12 is viewed from the depth side in the depth direction is shown. The thermal overload relay 71 has a shifter 72 that differs in shape from the shifter 22 of the embodiment. In the thermal overload relay 71 of the comparative example, the shifter 72 pushed by the bimetal 21 directly pushes the reversing mechanism 24, thereby tripping. Since the number of elements in the two-element structure is smaller than that in the three-element structure, the amount of displacement of the shifter 72 is correspondingly reduced. In order to obtain the same amount of displacement with the two-element structure as with the three-element structure, the design of the heater 26 needs to be reviewed. there is a possibility. That is, the heater 26 had to be designed separately for the two-element structure and the three-element structure, and could not be shared.

In addition, the position of the shifter 72 that pushes the compensating bimetal 31 is located on the other side in the vertical direction of the position that is pushed by the bimetal 21, and the point of force and the point of action are not arranged on a straight line along the width direction. Therefore, when the shifter 72 is pushed by the bimetal 21 , a clockwise moment acts on the shifter 72 as viewed from the far side in the depth direction, which acts as sliding resistance against the protrusion 45 . Therefore, the shape of the shifter 72 is enlarged to one side in the vertical direction from the position where it is pushed by the bimetal 21 when viewed from the depth direction, thereby suppressing the moment by weight balance. Therefore, it was an obstacle to weight reduction and space saving.

<<Second embodiment>>
"composition"
9 to 18 are diagrams showing a thermal overload relay according to a second embodiment of the invention. This thermal overload relay 80 is a 2E (two-element) type device with a three-element structure that protects against overload and loss of phase.
As shown in FIGS. 9 and 10, the thermal overload relay 80 of the second embodiment includes U, V, and W three- phase bimetals 21U, 21V, and 21W and a push shifter 81 inside the case 12. , a pull shifter 82, a differential lever 83, a reversing mechanism 24, and a reset rod 25 are arranged. Here, the differential lever 83 is described as a lever in the present invention.
The three- phase bimetals 21U, 21V, and 21W extend in the depth direction and are formed in a plate shape along the vertical and depth directions, with the front side in the depth direction serving as a fixed end and the depth side serving as a free end. Each bimetal 21 is connected to the main terminal at the front side in the depth direction, and is joined to one end of the heater 26 at the back side in the depth direction. The heater 26 is wound around each bimetal 21, and the other end is joined to the connection terminal 27 on the front side in the depth direction.

The push shifter 81 and the pull shifter 82 are supported by the case 12 so that their thickness directions are flush with each other. In an overloaded state, the three- phase bimetals 21U, 21V, and 21W bend, causing the push shifter 81 to be displaced to the other side in the width direction. . Further, when an open phase occurs, the non-curving bimetal of the phase in which the open phase has occurred restricts the displacement of the pull shifter 82 so that the push shifter 81 is displaced in the same manner as in an overloaded state.
The reversing mechanism 24 and the reset rod 25 have the same configuration as the thermal overload relay 11 of the first embodiment shown in FIGS.

As shown in FIG. 10, the case 12 has partition walls 41 to 43 and a girder plate 44 formed inside the case 12 . Here, the girder plate 44 is described as a case wall in the present invention. A plurality of projections 45a1 and 45b1 are formed side by side along the width direction on the other sides of the partition walls 41 to 43 in the vertical direction. The protrusions 45a1 formed on the partition walls 41 and 43 protrude in a columnar shape. The projecting portion 45b1 formed on the partition wall 42 includes a column portion 48a that protrudes from the partition wall 42 and a head portion 48b that protrudes from the tip of the column portion 48a toward the other side in the vertical direction. A plurality of protrusions 45a2 and 45b2 are also formed on one side of the partition walls 41 to 43 in the longitudinal direction so as to be aligned in the width direction. The protrusions 45a2 formed on the partition walls 41 and 43 protrude in a columnar shape. The projecting portion 45b2 formed on the partition wall 42 includes a column portion 49a that projects from the partition wall 42 and a head portion 49b that protrudes from the tip of the column portion 49a toward the other side in the vertical direction.

The push shifter 81 is an insulator having the same shape as the shifter 22 used in the thermal overload relay 11 of the first embodiment. That is, as shown in FIG. 10, the push shifter 81 has an elongated hole 51 formed on one widthwise side thereof into which the protrusion 45a1 of the partition wall 41 is fitted, and has a protrusion 45b1 of the partition wall 42 on the other widthwise side. , and an elongated hole 52 into which the protrusion 45a1 of the partition wall 43 is fitted. Here, the hole width on one side in the width direction of the elongated hole 52 is larger than the vertical dimension of the head portion 48b of the protrusion 45b1, and the hole width on the other side in the width direction of the elongated hole 52 is larger than the width of the protrusion 45b1. It is formed to be smaller than the vertical dimension of the head portion 48b and larger than the vertical dimension of the column portion 48a of the protrusion 45b1. One side of the elongated hole 52 in the width direction corresponds to the mounting hole described in the present invention. Engagement pieces 53 to 55 are formed on one side of the push shifter 81 in the vertical direction.

The pull shifter 82 is a substantially rectangular insulator with long sides in the width direction and short sides in the vertical direction. As shown in FIG. 11, the pull shifter 82 has an elongated hole 85 formed on one side in the width direction into which the protrusion 45a2 of the partition 41 is fitted, and a protrusion 45b2 of the partition 43 on the other side in the width direction. A mating slot 86 is formed, and a slot 87 is formed on one longitudinal side between the slots 85 and 86 . Here, the hole width on the other side in the width direction of the elongated hole 87 is larger than the vertical dimension of the head portion 49a of the protrusion 45b2, and the hole width on the one side in the width direction of the elongated hole 87 is larger than the width of the protrusion 45b2. It is formed to be smaller than the vertical dimension of the head portion 49a and larger than the vertical dimension of the portion of the projecting portion 45b2 that protrudes in a substantially cylindrical shape. The other widthwise side of the elongated hole 87 corresponds to the mounting hole described in the present invention. Engagement pieces 88 to 90 are formed on the other side of the pull shifter 82 in the vertical direction, and the other side of the pull shifter 82 in the width direction is open on the other side in the vertical direction. An engaging groove 91 is formed extending to the .

12 is a perspective view showing the differential lever 83, FIG. 13(a) is a view of the differential lever 83 viewed from the other side in the width direction, and FIG. It shows a cross section.
A pair of opposed plates 92 and 93 are formed on one side of the differential lever 83 in the vertical direction. The pair of opposing plates 92 and 93 are formed in a flat plate shape along the vertical direction and the width direction, face each other while being spaced apart in the depth direction, and are connected by a cylindrical support shaft 94 extending in the depth direction. The distance between the pair of opposing plates 92 and 93 is slightly larger than the thickness of the girder plate 44 of the case 12 , and the diameter of the support shaft 94 is slightly smaller than the groove width of the engagement groove 91 of the pull shifter 82 . On the other side of the differential lever 83 in the vertical direction, an end face 95 is formed which faces one side in the width direction and is flat along the vertical and depth directions. On the other side of the differential lever 83 in the vertical direction, an end face 96 that is a curved surface extending in the depth direction and protruding toward the other side in the width direction is formed.

14, the long hole 51 of the push shifter 81 is fitted to the protrusion 45a1 of the partition 41 of the case 12, and the long hole 52 is fitted to the protrusion 45b1 of the partition 42 and the protrusion 45a1 of the partition 43. Thus, they are arranged so as to be displaceable along the width direction. When the protrusion 45b1 of the partition wall 42 is located on one side of the elongated hole 52 in the width direction, the hole width is such that the head 48b can pass through, so that the push shifter 81 can be removed. When the projection 45b1 of the partition wall 42 is located on the other widthwise side of the elongated hole 52, the head 48b of the projection 45b1 prevents the push shifter 81 from being removed. The engaging piece 53 of the push shifter 81 engages the free end of the U-phase bimetal 21U from the other side in the width direction, and the engaging piece 54 engages the free end of the V-phase bimetal 21V in the other width direction. engaged from the side. The engaging piece 55 engages the free end of the W-phase bimetal 21W from the other side in the width direction, and the differential lever 83 engages with the tip 56 directed to the other side in the width direction.

As shown in FIG. 14, the pull shifter 82 has a long hole 85 fitted to the partition wall 41 and the projection 45a2 of the case 12, a long hole 86 fitted to the projection 45a2 of the partition wall 43, and a long hole 87 fitted to the partition wall 42. It is arranged so as to be displaceable along the width direction by being matched with the protrusion b2. When the protrusion 45b2 of the partition wall 42 is located on the other side of the elongated hole 58 in the width direction, the hole width is such that the head 49b can pass through, so that the pull shifter 82 can be removed. When the projection 45b2 of the partition wall 42 is located on one side of the elongated hole 58 in the width direction, the head 49b of the projection 45b2 prevents the pulling shifter 82 from being removed. The engaging piece 88 of the pull shifter 82 engages the free end of the U-phase bimetal 21U from one side in the width direction, and the engaging piece 89 engages the free end of the V-phase bimetal 21V in the width direction. engaged from the side. The engaging piece 90 is engaged with the free end of the W-phase bimetal 21W from one side in the width direction.

As shown in FIGS. 14 and 15, the differential lever 83 is attached to the case 12 by a pair of opposing plates 92 and 93 sandwiching the girder plate 44 of the case 12 and the support shaft 94 fitting into the engagement groove 91. It is rotatably supported around a support shaft 94 . An end face 95 facing one side in the width direction of the differential lever 83 engages with the tip 56 of the engagement piece 55 of the push shifter 81 . A free end of the compensating bimetal 31 of the reversing mechanism 24 is engaged with the end face 96 of the differential lever 83 facing the other side in the width direction.

<<Operation of Second Embodiment>>
In the thermal overload relay 80 of the second embodiment, when overloaded, the three- phase bimetals 21U, 21V, and 21W bend to displace the push shifter 81 and the pull shifter 82 to the other side in the width direction. . As the push shifter 81 and the pull shifter 8 are displaced to the other side in the width direction, the end face 94 of the differential lever 83 is pushed by the tip of the engaging piece 55 and rotates counterclockwise about the support shaft 93 . move. As a result, the free end of the compensating bimetal 31 is displaced to the other side in the width direction, so that the reversing mechanism 24 is in a trip state in which the contact a is closed and the contact b is opened.

Also, a case where phase loss occurs in any of the three- phase bimetals 21U, 21V, and 21W will be described. As an example, if the U-phase bimetal 21U is open-phase, the bimetal 21U is not heated by the other- phase bimetals 21V and 21W and is at a low temperature. It becomes smaller than other bimetals 21V and 21W. When the bending displacement amounts of the three- phase bimetals 21U, 21V, and 21W change for each phase in this way, the push shifter 81 is displaced toward the compensating bimetal 31 by the displacement amount of the bimetals 21V and 21W having the largest bending displacement. The shifter 82 is displaced only by the amount of displacement of the bimetal 12U having the smallest bending displacement, and a difference is generated between the displacement amounts of the push shifter 81 and the pull shifter 82 . When such a differential occurs, the amount of counterclockwise rotation of the differential lever 83 around the support shaft 94 becomes greater than in the overload state. Due to the rotation of the differential lever 83 , the amount of displacement of the differential lever 83 becomes larger than the amount of displacement of the push shifter 81 . As a result, when an open phase occurs, the trip state occurs earlier than when an overload current flows.

《Assembly of Push Shifter, Pull Shifter and Differential Lever》
Next, the assembly of the push shifter 81, the pull shifter 82 and the differential lever 83 that constitute the thermal overload relay 80 of the second embodiment will be described.
First, the assembly of the pull shifter 82 will be described with reference to FIG. The pull shifter 82 is moved from the depth side toward the front side in the depth direction to the side where the protrusions 45a2 and 45b2 of the partition walls 41 to 43 are provided. Then, the projection 45a2 is fitted into the elongated holes 85 and 86 of the pull shifter 82, and the head 49b of the projection 45b2 is fitted to the other side (mounting hole) of the elongated hole 87 in the width direction. Next, the pull shifter 82 is slid toward the other side in the width direction (in the direction of arrow S1 shown in FIG. 16). At this time, the engagement pieces 88 to 90 are engaged with the free ends of the three- phase bimetals 21U, 21V, and 21W from one side in the width direction, and the alignment of the pull shifter 82 is completed. When the positioning of the pull shifter 82 is completed, the protrusion 45b2 moves to one side of the elongated hole 87 in the width direction, and the head 49b of the protrusion 45b2 moves toward the one side of the elongated hole 87 in the width direction. The pulling shifter 82 is attached to the case 12 in such a manner that it is prevented from coming off to the far side in the depth direction.

Next, assembly of the push shifter 81 will be described with reference to FIG. The push shifter 81 is moved from the depth side toward the front side in the depth direction to the side where the protrusions 45a1 and 45b1 of the partition walls 41 to 43 are provided. Then, the protrusion 45a1 is fitted into the elongated hole 51 of the push shifter 81, and the head 48b of the protrusion 45b1 is fitted to one side (mounting hole) of the elongated hole 52 in the width direction. Next, the push shifter 81 is slid toward one side in the width direction (direction of arrow S2 shown in FIG. 17). At this time, the engagement pieces 53 to 55 are engaged with the free ends of the three- phase bimetals 21U, 21V, and 21W from the other side in the width direction, and the alignment of the push shifter 81 is completed. When the positioning of the push shifter 81 is completed, the protrusion 45b1 moves to the other side of the elongated hole 52 in the width direction, and the head 48b of the protrusion 45b1 prevents the other side of the elongated hole 52 from coming off. Then, the push shifter 81 is attached to the case 12 in a state in which it is prevented from coming off to the far side in the depth direction.

Next, assembly of the differential lever 33 will be described with reference to FIGS. 15 and 18. FIG. The differential lever 33 is moved to one side in the vertical direction (in the direction of arrow S3 in FIG. 18) until the pair of opposing plates 92 and 93 come into contact with the engagement groove 91 of the pull shifter 82 and the girder plate 44 . As a result, as shown in FIG. 15, the differential lever 33 is arranged with the pair of opposing plates 92 and 93 sandwiching the girder plate 44, and the differential lever 33 is prevented from falling off to the far side in the depth direction. 12 is assembled.
In the procedure for assembling the push shifter 81, the pull shifter 82 and the differential lever 83 described above, the pull shifter 82 and then the push shifter 81 were assembled to the case 12 in that order. can be assembled to the case 12 in this order.

<<Action of Second Embodiment>>
Next, main functions of the thermal overload relay 80 of the second embodiment will be described.
The push shifter 81 fits the projection 45a1 into the long hole 51 by moving from the far side in the depth direction toward the near side, and the head of the projection 45b1 is fitted to one side (mounting hole) in the width direction of the long hole 52. After fitting the portion 48b, it slides toward one side in the width direction. As a result, the engaging pieces 53 to 55 of the push shifter 81 are engaged with the free ends of the three- phase bimetals 21U, 21V and 21W, completing the alignment. The push shifter 81 that has been aligned is assembled to the case 12 with the head 48b of the projection 45b1 functioning as a stopper from the other side of the elongated hole 52 to prevent it from coming off.

Further, the pull shifter 82 is moved from the far side in the depth direction toward the front side so that the protrusions 45a2 are fitted in the long holes 85 and 86, and the other side (mounting hole) of the long hole 87 in the width direction is projected. After fitting the head portion 49b of the portion 45b2, it slides toward the other side in the width direction. As a result, the engaging pieces 88 to 90 of the push shifter 81 are engaged with the free ends of the three- phase bimetals 21U, 21V and 21W, completing the alignment. The pull shifter 82 that has completed this positioning is also attached to the case 12 in a state in which the head 49b of the protrusion 45b2 functions as a retainer from one side of the elongated hole 87 in the width direction, preventing the pull shifter 82 from coming off.

When the differential lever 33 moves to one side in the vertical direction, the support shaft 94 fits into the engagement groove 91 of the pull shifter 82 , and the end face 95 facing one side in the width direction is attached to the push shifter 81 . Alignment is completed when the end face 96 that engages with the tip 56 of the engaging piece 55 and faces the other side in the width direction engages with the compensating bimetal 31 of the reversing mechanism 24 . The differential lever 33 that has been aligned is attached to the case 12 in a state in which the girder plate 44 of the case 12 is sandwiched between the pair of opposing plates 92 and 93 to prevent the differential lever 33 from falling off.
Therefore, each component of the push shifter 81, the pull shifter 82, and the differential lever 33 can be individually slid and assembled into the case 12, thereby simplifying the assembly procedure.

In addition, since the push shifter 81, the pull shifter 82 and the differential lever 33 can be assembled by moving in the depth direction, vertical direction and width direction perpendicular to the three-dimensional direction, automatic assembly by a robot hand is realized. can do.
Furthermore, even if the half-finished thermal overload relay 80 is transported on the line, the push shifter 81, the pull shifter 82 and the differential lever 33 can be reliably prevented from falling off from the case 12. Production efficiency can be improved.
Although the foregoing has been described with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure will be obvious to those skilled in the art.

11 Thermal overload relay 12 Case 21, 21U, 21V, 21W Bimetal 22 Shifter 23 Lever 24 Reversing mechanism 25 Reset rod 26 Heater 27 Connection terminal 31 Compensating bimetal 32 Release lever 33 Tension spring 34 Movable plate 35 Leaf spring 36 Interlocking plate 41 Partition wall 42 Partition wall 43 Partition wall 44 Girder plate (wall portion) , 45, 45a1, 45b1, 45a2, 45b2... Protrusion 46... Groove 47... Plate spring 48a, 49a... Column part 48b, 49b... Head 51... Long hole 52... Long hole 53... Engaging piece 54 Engaging piece 55 Engaging piece 56 Tip 61 Opposing plate 62 Opposing plate 63 Support shaft 64 End face 65 End face 71 Thermal overload Relay 72 Shifter 80 Thermal overload relay 81 Push shifter 82 Pull shifter 83 Differential lever (lever) 85 to 87 Long hole 87 to 89 Engaging piece 90 ... engagement groove, 91, 92 ... facing plate, 93 ... spindle, 94 ... end face, 95 ... end face

Claims (10)

1. In a thermal overload relay with a two-element structure that protects against overload,
   a bimetal that bends when heated, and
   a shifter that is pushed and displaced by the bimetal when the bimetal is bent;
   a lever rotatably supported by a support shaft and rotated by being pushed by the shifter when the shifter is displaced;
   a reversing mechanism for reversing a contact by being pushed from a position radially outside a position of the lever pushed by the shifter when the lever rotates. overload relay.
2. The lever adjusts the position of the support shaft serving as the rotation center, the position pushed by the shifter, and the position pushed against the reversing mechanism, thereby adjusting the amplification factor of the amount of displacement in the shifter. A thermal overload relay according to claim 1.
3. When the bimetal is not bent, the position of the support shaft serving as the center of rotation and the position of pressing the reversing mechanism when viewed from the axial direction of the support shaft correspond to the direction of pressing the reversing mechanism. 3. The thermal overload relay according to claim 1 or 2, wherein the thermal overload relays are arranged in a direction perpendicular to the .
4. 3. The thermal overload according to claim 1, wherein said shifter has a position where said bimetal pushes and a position where said lever is pushed on a straight line along the direction of displacement. relay.
5. The shifter has a flat plate shape,
   3. The thermal overload relay according to claim 1, wherein the lever extends in a direction perpendicular to the surface of the shifter and rotates in the surface direction of the shifter.
6. a plurality of partition walls provided inside the case;
   a plurality of bimetals arranged between the plurality of partition walls and curved when heated;
   a shifter mounted so as to cover ends of the plurality of partition walls and displaced by being pushed by the bimetal when the bimetal is bent;
   a lever that is rotated by being pushed by the displacement of the shifter;
   A thermal overload relay comprising a reversing mechanism that reverses the contacts by being pushed by the rotation of the lever,
   a plurality of elongated holes formed so as to extend in the displacement direction of the shifter;
   a plurality of protrusions projecting from end surfaces of the plurality of partition walls and slidably fitted into the plurality of elongated holes for guiding displacement of the shifter;
   and a shifter drop-off preventing portion configured to prevent the shifter from dropping off from the partition wall by moving the shifter, in which the plurality of elongated holes are fitted to the plurality of protrusions, in a displacement direction. thermal overload relay.
7. The shifter detachment prevention portion includes:
   a head formed at a tip of a predetermined protrusion among the plurality of protrusions and protruding in a direction orthogonal to the displacement direction within the same plane;
   a mounting hole formed at the end of the elongated hole that fits the predetermined projection and through which the head can pass;
   7. The shifter having the head passed through the mounting hole is moved in the direction of displacement so that the head functions as a stopper for the projection from the elongated hole. thermal overload relay.
8. The lever is provided with a lever drop-off preventing portion that engages with a wall portion of the case to prevent the lever from dropping off when the lever is engaged with the shifter in a direction orthogonal to the displacement direction within the same plane. 8. The thermal overload relay according to claim 6 or 7, characterized in that:
9. The thermal overload relay according to claim 6, characterized in that said lever drop-off preventing portion is a pair of opposing plates formed on said lever that sandwiches the wall portion of said case.
10. The shifters are push shifters and pull shifters that are displaced by engaging with the plurality of bimetals from one and the other of the displacement directions,
    8. The thermal overload relay according to claim 6, wherein said push shifter and said pull shifter are each provided with said shifter drop-out preventing portion.

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