JP2010009762A - Thermal relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal relay that can be arranged in a narrow space and facilitates determination of a manual reset state and an automatic reset state. <P>SOLUTION: The thermal relay 1 has a movable plate 61, which is oscillated in accordance with displacement of a bimetal 10, and a spring 61 that is expanded/contracted in accordance with the oscillation of the movable plate 61 and holds the movable plate 61 in a first state and in a second state each in which an open/closed state of a contact is different from each other. The spring 61 passes through the dead center where a biasing force becomes maximum during a shift from the first state to the second state. Further, the thermal relay is provided with a reset member 80 that executes switching between a manual return state and an automatic return state and return from the second state to the first state. The reset member 80 extends a blade spring 45 to the side of the movable plate 61 such that the oscillation range of the movable plate 61 does not pass through the position corresponding to the dead center of the spring 61 during switching from the manual return state to the automatic return state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermal relay (thermal overload relay) that operates a contact mechanism using a bimetal bending displacement caused by a temperature rise, and in particular, switches a contact between a manual return state and an automatic return state and performs manual return. The present invention relates to a reset mechanism that performs a reset operation in a state.

  The thermal relay switches between opening and closing of the normally open contact and the normally closed contact by a contact switching mechanism that operates according to the bending displacement of the bimetal. The thermal relay is provided with a reset member in order to return (reset) the initial state after each contact is switched by the contact switching mechanism. The reset method includes a manual reset method that manually operates the reset member to return each contact to the initial state, and an automatic reset method that automatically returns the reset member to the initial state.

As such a reset member, there has been proposed a cylindrical push-type reset bar that takes a manual reset state by pushing and rotates after being pushed to take an automatic reset state (for example, Patent Document 1, Patent) Reference 2). The reset bar described in Patent Document 1 includes a claw that prevents unexpected switching from a manual reset state to an automatic reset state. When switching to the automatic reset state, the claws are broken. Further, the reset bar described in Patent Document 2 is provided with means for applying resistance when the reset bar is pushed. When switching from the manual reset state to the automatic reset state or vice versa, an erroneous switching is prevented by generating a response against the resistance means. Further, a dial-shaped pointer portion indicating a manual reset state and an automatic reset state is provided on the head of the reset bar.
JP 2002-170471 A JP 2002-237246 A

In the thermal relay disclosed in Patent Documents 1 and 2, since the space for rotating the rod-shaped member and the protruding portion protruding from the outer peripheral surface in the case of the thermal relay is required, the case size is increased. Was the cause. In the case of the push-push type, there is a problem that it is difficult to visually determine whether the reset bar is in a manual return state or an automatic return state. In the thermal relay described in Patent Document 2, a pointer portion indicating each state is provided on the head of the reset rod. However, it is necessary to check the direction of the pointer portion each time.
Furthermore, in the thermal relay described in Patent Document 1, it is necessary to treat the claws that have been broken off.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a thermal relay that can be arranged in a narrow space and can easily determine a manual reset state and an automatic reset state.

  The thermal relay of the present invention comprises: a bimetal that is bent when the temperature is raised; a heating unit that generates heat by heating a main circuit current; and switches between opening and closing of the contacts according to the bending displacement of the plurality of bimetals. A contact switching mechanism having a first state and a second state with different opening and closing states, holding means for holding the contact switching mechanism in the first state or the second state, and the contact switching mechanism in the first state. Switching between the manual return state in which the transition from the state 1 to the second state is permitted and the automatic return state in which the transition is prevented, and the return from the second state to the first state A reset member that performs a return to the first state from the second state by moving in the first direction, and By the movement in the second direction different from the first direction, characterized in that for switching between the automatic return state and the manual reset state.

According to the present invention, the direction of movement of the reset member when the transition from the second state to the first state is performed (in the case of manual return), and the reset member when the transition is prevented (in the case of automatic return). The moving direction of is different. That is, the position of the reset member in the manual return state is different from the position of the reset member in the automatic return state. On the other hand, for example, in the case of the push-type cylindrical reset member described in the above-described conventional example, the direction of the reset member is different between the manual return state and the automatic return state, but the position (posture) is almost the same. Absent. Therefore, according to the present invention, it is easy to determine whether the contact is in the manual return state or the automatic return state by checking the position of the reset member.
Further, according to the present invention, unlike the push-type columnar reset member, it is not necessary to secure a space for the protrusions and the like to rotate in the circumferential direction, so that the reset mechanism is accommodated in a relatively narrow space. The structure of the thermal relay can be made compact.

  In the present invention, the movement of the reset member in the first direction is a straight movement in the direction of being pushed into the case, and the movement in the second direction is a direction substantially orthogonal to the first direction. It is preferable that the movement is straight ahead.

  By setting the moving direction of the reset member to the straight direction, the reset member can be moved in a narrow space. For example, if the movement direction of the reset member is the movement in the vertical direction (height direction) and the front-rear direction of the case along the inner surface of the case side plate, the empty space in the case can be used effectively.

  Furthermore, in this invention, it is preferable that the said case is provided with the cover part which covers the protrusion part of the said reset member when it is the said automatic return state.

  By making the position of the reset member different between the automatic return state and the manual return state, and covering the protruding end portion of the reset member with the cover portion, the difference in the posture of the reset member in each state can be further clarified. Therefore, it can be determined at a glance that the state is the automatic return state.

  According to a specific aspect of the thermal relay of the present invention, the contact switching mechanism includes a swinging member that transmits the displacement of the bimetal to the contact and swings according to the displacement of the bimetal, Has a spring element that expands and contracts in response to the swing of the swing member, and passes through a dead point where the urging force is maximized when shifting from the first state to the second state, and the reset member Is a control member that restricts the swing range of the swing member from passing through a position corresponding to the dead point of the spring element when switching from the manual return state to the automatic return state. Can be extended to

  As described above, according to the present invention, the position of the reset member differs between the manual return state and the automatic return state. Further, in the automatic return state, since the protruding end portion of the reset member is covered with the cover, not only the position of the reset member but also the posture of the reset member is different in each state. Therefore, it can be easily determined in which state. Further, since the moving direction of the reset member is the vertical direction and the front-rear direction along the inner surface of the case side plate, the reset member can be moved using a narrow space in the case, and the thermal relay case is downsized. be able to.

Embodiments of a thermal relay to which the present invention is applied will be described below with reference to the drawings. In the following description, the descriptions of the vertical direction, the horizontal direction, and the like are all based on the posture / position in the drawing and are not related to the direction when the thermal relay is actually used.
FIG. 1 is a front view showing a main part structure of a thermal relay (in an initial state) of the present embodiment.
FIG. 2 is a front view showing a main part structure of the thermal relay of FIG. 1 at the time of resetting. 1 and 2 show the thermal relay case with the back cover removed. Further, in FIG. 2, some parts (link assembly, temperature compensation bimetal) are omitted in order to easily show the contact switching mechanism.
FIG. 3 is a front view for explaining the structure of a leaf spring to which a normally open contact is attached. FIG. 3 (A) shows an initial state, and FIG. 3 (B) shows a reset state.
The thermal relay 1 includes a plurality of bimetals 10 that are accommodated in the case 3 and that are curved when the temperature rises, and heaters 20 (heating means) that heat the bimetals 10. Furthermore, the normally open contact 40 and the normally closed contact 50, the contact switching mechanism 60 for switching the opening and closing of each contact according to the bending displacement of the bimetal 10 due to the temperature rise, and the coil spring (holding means) for holding each contact in the open state or the closed state. 70. Furthermore, the reset member 80 which resets the contact switching mechanism 60 to the state before switching is provided. The state in which the normally open contact 40 is open and the normally closed contact 50 is closed is referred to as a first state (also referred to as an initial state), and the state in which the normally open contact 40 is closed and the normally closed contact 50 is open is a second state. It is called the state.

  The bimetal 10 is a strip-shaped member formed by laminating a pair of metal plates having different coefficients of thermal expansion, and usually three main bimetals corresponding to the three phases of U, V, and W phases. It consists of 10U, 10V, 10W. Each main bimetal 10 is wound with heaters 20U, 20V, and 20W. Each heater 20 generates heat according to the magnitude of the passed current, and heats the main bimetal 10 of each phase.

  One end (upper end in the figure) of each main bimetal 10 is fixed to the in-case fixed object 2, and the shifter 11 is engaged with the other end (lower end). When the main bimetal 10 is heated by the heater 20 and rises in temperature, the main bimetal 10 is displaced in the right direction in the figure, and the shifter 11 moves in the right direction in the figure along with this displacement.

  As shown in FIG. 1, a temperature compensating bimetal 13 is disposed in front of the shifter 11 in the moving direction. The compensation bimetal 13 is joined to the link assembly 15. The link assembly 15 is interlocked with an adjustment dial 17 that adjusts the current at which the thermal relay operates, and has a C-shaped holding portion 15a at the lower end portion and a link shaft 15b extending upward from the holding portion 15a. The holding portion 15a is rotatably held by a rod 19 that is rotatably attached to the case shaft of the in-case fixing portion 2. The upper end of the compensation bimetal 13 is joined to the holding portion 15 a of the link assembly 15, and the lower end is located in front of the shifter 11 in the moving direction. The upper end of the link shaft 15 b is in contact with the cam of the adjustment dial 17.

  When the bending displacement amount of the main bimetal 10 exceeds a predetermined value, the compensation bimetal 13 moves to the right in the drawing via the shifter 11, and the rod 19 moves to the right along with it.

The contact switching mechanism will be described with reference to FIG.
The contact switching mechanism 60 switches each contact between the first state and the second state by the movement of the rod 19, and has a movable plate (swing member) 61 and a trip lever 63. The movable plate 61 is a plate-like member, and one end thereof is supported by the in-case fixed portion 2 so as to be swingable. The trip lever 63 is an L-shaped member having a first arm portion 63a and a second arm portion 63b that form a substantially right angle. The lever 63 is rotatably supported by the in-case fixing portion 2 at the center (intersection of the first arm portion 63a and the second arm portion 63b). The free end of the movable plate 61 is engaged with the groove at the tip of the first arm portion 63 a of the trip lever 63. As a result, when the movable plate 61 swings in the clockwise direction in the figure, the trip lever 61 rotates in the counterclockwise direction in the figure around the fulcrum.

  The normally open contact 40 has a movable contact 41 and a fixed contact 42 facing each other. The movable contact 41 is attached to a substantially central portion in the length direction of the movable plate 61. On the other hand, the fixed contact 42 is attached to the leaf spring 45. Specifically, as shown in FIG. 3, the tip of the leaf spring 45 is formed with a step 45 a that is bent in a step shape. The leaf spring 45 is supported in a cantilever manner so that a space is opened between the back surface of the spring body and the inner surface of the case side plate 4 and the stepped portion 45 a is in contact with the inner surface of the side plate 4. In the initial state shown in FIGS. 1 and 2 (FIG. 3A), the movable contact 41 and the fixed contact 42 are separated from each other.

  The normally closed contact 50 has a movable contact 51 and a fixed contact 52 facing each other. As shown in FIG. 2, the movable contact 51 is attached to a substantially central portion of a leaf spring 53 supported in a cantilever manner. The tip of the leaf spring 53 is located in front of the tip of the second arm portion 63 b of the trip lever 63 in the rotational direction. The fixed contact 52 is fixed at a position facing the movable contact 51. In the initial state shown in FIGS. 1 and 2, the movable contact 51 and the fixed contact 52 are in contact with each other.

  The tension spring 70 is disposed in front of the moving direction of the rod 19 (not shown in FIG. 2), one end is fixed to the substantially central portion in the length direction of the movable plate 61, and the other end is the case. It is fixed to the inner fixing part 2. The tension spring 70 urges the movable plate 61 to swing in the counterclockwise direction in the drawing to maintain the contacts 40 and 50 in the first state.

Next, the operation of the contact switching mechanism in the manual return state will be described with reference to FIG.
4A is a front view showing the structure of the main part of the thermal relay in the first state, and FIG. 4B is a front view showing the structure of the main part of the thermal relay in the second state. . In these figures, the reset member is omitted.
When the main circuit current increases and the temperature of the bimetal 10 is increased, the compensation bimetal 13 (not shown in FIG. 4) moves to the right in the figure via the shifter 11, and accordingly the rod 19 (FIG. 4). Moves to the right and pushes the tension spring 70 to the right. Then, the tension spring 70 starts to rotate in the clockwise direction in the figure, and along with this rotation, the movable plate 61 starts to swing in the clockwise direction in the figure against the force of the spring 70. When the urging force of the spring 70 becomes maximum and the direction of urging the movable plate 61 exceeds the dead center where the counterclockwise direction changes from the counterclockwise direction to the clockwise direction, the movable plate 61 is rapidly moved by the urging force of the spring 70. Swing in the direction. 4B, the movable contact 41 of the normally open contact 40 attached to the movable plate 61 contacts the fixed contact 42 attached to the leaf spring 45.

  And the front-end | tip of the movable plate 61 pushes the 1st arm part 63a of the trip lever 63 engaged, and the trip lever 63 rotates counterclockwise of a figure. Then, the second arm portion 63 b of the trip lever 63 presses the tip of the leaf spring 53 to which the movable contact 51 of the normally closed contact 50 is attached, and the movable contact 51 of the normally closed contact 50 is separated from the fixed contact 52. That is, the normally open contact 40 is closed and the normally closed contact 50 is opened.

Next, the reset member 80 will be described.
FIG. 5 is an exploded perspective view showing a structure of a portion to which the reset member is attached.
FIG. 6 is a perspective view showing the structure of the main part of the thermal relay in the initial state (first state).
FIG. 7 is a perspective view showing the position of the reset member in the initial state (first state).
The reset member 80 is for performing a reset operation for returning the contacts 40 and 50 from the second state to the first state. That is, the leaf spring 45 to which the fixed contact 41 of the normally open contact 40 is attached is pushed to swing the movable plate 61 to a position exceeding the dead point. When the movable plate 61 swings to a position exceeding the dead point, the movable plate 61 swings to the initial position by the biasing force of the spring 70.

  As shown in FIG. 5, the reset member 80 is a plate-like member extending substantially along the vertical direction of the case 3, and in order from the top, a horizontal protruding end portion 81, a central portion 82 that accommodates the torsion coil spring 85, A vertical portion 83 depending from the central portion 82 and a restricting portion 84 extending from the lower end of the vertical portion 83 in a direction (front-rear direction) perpendicular to the vertical portion. The reset member 80 is attached so as to be slidable in the vertical direction and the front-rear direction along the inner surface of the side plate 4 of the case 3. The reset member 80 is integrally formed by, for example, injection molding of a resin material.

As shown in FIGS. 6 and 7, the protruding end portion 81 protrudes from the front end of the slit 5 a formed in the top plate 5 of the case and extending in the front-rear direction. A cover 7 is provided at the rear of the slit 5a to cover the upper end.
The center portion 82 is formed with a space in which the torsion coil spring 85 is accommodated and surrounded by the upper surface, one side surface, and the back surface. A shaft 82a on which the winding portion of the torsion coil spring 85 is held projects from the back surface. In the torsion coil spring 85, the winding portion is held by the shaft 82a, one arm portion is in contact with the fixed portion 2 in the case, and the other arm portion is in contact with the upper surface of the center portion 82. By the torsion coil spring 85, the upper surface of the central portion 82 is biased upward with respect to the fixed portion 2, the reset member 80 is biased upward, and the protruding end portion 81 protrudes from the top plate 5.
The restricting portion 84 is thicker than the vertical portion 83, and the lower portion of the front surface is a tapered surface 84a that tapers downward.

  As shown in FIGS. 6 and 7, at the initial position, the reset member 80 is urged upward by the torsion coil spring 85, and the protruding end 81 protrudes from the front end of the slit 5a. Further, as shown in FIG. 3A and FIG. 7, the vertical portion 83 is in contact with the inner surface of the case side plate 4, and the regulating portion 84 is a leaf spring 45 to which the fixed contact 42 of the normally open contact 40 is attached. The space between the back surface of the main body and the inner surface of the case side plate 4 enters.

Hereinafter, the reset operation in the manual return state and the operation of the reset member 80 when switching between the manual return state and the automatic return state will be described.
FIG. 8 is a front view showing a state where the reset member is pushed.
FIG. 9 is a perspective view showing the position of the reset member in a state where the reset member is pushed.
6 and 7, when the user presses the protruding end 81 downward (first direction) against the urging force of the torsion coil spring 85, the reset member 80 slides downward, and the restricting portion 84. However, it moves downward from the space between the back surface of the main body of the leaf spring 45 and the inner wall of the case side plate 4. 3B, the taper portion 84a of the restricting portion 84 sinks into the back surface of the step portion 45a of the plate spring 45, and the step portion 45a rides on the front surface of the restricting portion 84, so that the plate spring 45 Rotates clockwise in the figure. Since the plate spring 45 and the movable plate 61 are in contact with each other via the fixed contact 42 and the movable contact 41, when the plate spring 45 rotates, the movable plate 61 is pushed by the plate spring 45, as shown in FIG. Starts swinging counterclockwise. The thickness of the restricting portion 84 is set so that the swing angle of the leaf spring 45 is an angle that swings the movable plate 61 from the dead center to the initial position. In other words, the movable plate 61 passes over the dead point and is biased by the spring 70 to return to the initial position (reset). As a result, the movable contact 41 of the normally open contact 40 is separated from the fixed contact 42 as shown in FIG. Further, the trip lever 63 rotates in the clockwise direction in the drawing by the rotation of the movable plate 61, the pressing force of the leaf spring 53 is released, and the movable contact 51 of the normally closed contact 50 contacts the fixed contact 52. That is, the process returns to the first state.

Next, the automatic return state will be described.
FIG. 10 is a perspective view showing the position of the reset member in the automatic return state.
After returning to the first state, the inside of the slit 5a is slid rearward (second direction) while the protrusion 81 of the reset member 80 is pressed. Since the restricting portion 84 of the reset member 80 has a certain width, even when the reset member 80 is slid, the state where the stepped portion 45a of the leaf spring 45 rides on the front surface of the restricting portion 84 is maintained. . Further, when the reset member 80 is slid rearward, the projecting end portion 81 eventually engages with the cover 7 provided on the case top plate 5. Thereby, the reset member 80 is restricted from moving upward and is maintained in a pressed state. Further, the central portion 82 of the reset member 80 enters the concave portion of the in-case fixing portion 2, and this also restricts the upward movement of the reset member 80. In this state, as shown in FIG. 8 (FIG. 3B), the stepped portion 45a of the leaf spring 45 rides on the restricting portion 84 of the reset member 80, and the leaf spring 45 is held in the position swung clockwise in the drawing. In this state, when the movable plate 61 starts to swing in the clockwise direction in the figure, the plate 61 hits the leaf spring 45 and is biased by the spring 70 in the middle of swinging to return to the initial state ( Automatically reset).
Further, since the protruding end 81 of the reset member 80 is hidden by the cover 7, it can be determined at a glance that it is in the automatic reset state.

(Other embodiments)
In addition, this invention is not limited only to above-described embodiment, Various application and deformation | transformation can be considered. For example, the structure of the thermal relay and the shape and material of each component are not limited to those of the above-described embodiment, and can be changed as appropriate.
For example, although the torsion coil spring is used to bias the reset member upward in the above-described embodiment, a coil spring may be used.
FIG. 11 is a perspective view showing a structure of a main part of a thermal relay including a reset member using a coil spring.
The central portion 82 of the reset member 80 in this example is not provided with a shaft for holding the winding portion of the torsion coil spring, and the central portion 82 is provided with a partition wall that supports the coil spring 86 in the height direction. Yes. The coil spring 86 is accommodated between the partition wall and the side surface of the central portion 82 and biases the upper surface upward with respect to the fixed portion 2. As a result, the reset member 80 is biased upward.

It is a front view which shows the principal part structure of the thermal relay (at the time of an initial state) of this embodiment. It is a front view which shows the principal part structure of the thermal relay of FIG. 1 at the time of reset. It is a front view explaining the structure of the leaf | plate spring to which a normally open contact is attached, FIG. 3 (A) shows an initial state and FIG. 3 (B) shows a reset state. 4A is a front view showing the structure of the main part of the thermal relay in the first state, and FIG. 4B is a front view showing the structure of the main part of the thermal relay in the second state. . It is a disassembled perspective view which shows the structure of the part to which the reset member is attached. It is a perspective view which shows the structure of the principal part of the thermal relay in an initial state (1st state). It is a perspective view which shows the position of the reset member in an initial state (1st state). It is a front view which shows the state by which the reset member was pushed. It is a perspective view which shows the position of the reset member in the state in which the reset member was pushed. It is a perspective view which shows the position of the reset member in an automatic return state. It is a perspective view which shows the structure of the principal part of the thermal relay provided with the reset member which uses a coil spring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal relay 2 Case fixed part 3 Case 4 Case side plate 5 Case top plate 7 Cover 10 Bimetal 11 Shifter 13 Temperature compensation bimetal 15 Link assembly 17 Adjustment dial 19 Rod 20 Heater 40 Normally open contact 41 Movable contact 42 Fixed contact 45 Plate spring 50 normally closed contact 51 movable contact 52 fixed contact 53 leaf spring 60 contact switching mechanism 61 movable plate 63 trip lever 70 spring 80 reset member 81 projecting end portion 82 central portion 83 vertical portion 84 regulating portion 85 torsion coil spring 86 coil spring

Claims (4)

Bimetal that curves when the temperature rises,
Heating means for generating heat by the main circuit current and heating the bimetal;
A contact switching mechanism that switches between opening and closing of the contacts in accordance with the bending displacement of the plurality of bimetals, and has a first state and a second state in which the opening and closing states of the contacts are different;
Holding means for holding the contact switching mechanism in the first state or the second state;
The contact switching mechanism is switched between a manual return state in which the transition from the first state to the second state is permitted and an automatic return state in which the transition is prevented, and from the second state to the first state. A reset member for returning to the state of 1;
A thermal relay comprising:
The reset member returns from the second state to the first state by moving in the first direction, and the manual return by moving in a second direction different from the first direction. A thermal relay that switches between a state and an automatic return state.   The movement of the reset member in the first direction is a straight movement in a direction to be pushed into the case, and the movement in the second direction is a straight movement in a direction substantially orthogonal to the first direction. The thermal relay according to claim 1, wherein the thermal relay is provided.   The thermal relay according to claim 2, wherein the case includes a cover portion that covers a protruding end portion of the reset member when the case is in the automatic return state. The contact switching mechanism has a swinging member that transmits the displacement of the bimetal to the contact and swings according to the displacement of the bimetal,
The holding means has a spring element that expands and contracts in response to the swing of the swing member, and passes through a dead point where the urging force becomes maximum at the time of transition from the first state to the second state,
The reset member controls the rocking member that restricts the rocking range of the rocking member from passing a position corresponding to the dead point of the spring element when switching from the manual return state to the automatic return state. The thermal relay according to any one of claims 1 to 3, wherein the thermal relay is extended to a moving member side.