Electronic Overload Relay

Abstract

To realize cost reduction and size reduction by reducing the number of components used for switching a contact mechanism.SOLUTION: An electronic overload relay includes a contact mechanism that can be switched between a steady state and a trip state, an electromagnet having a movable shaft that moves in the axial direction when energized, a slider that moves in the axial direction in conjunction with the movable shaft when energized, and a driven member that alternately switches the stop position of the slider after movement in the axial direction between a first stop position corresponding to the steady state and a second stop position corresponding to the trip state each time the electromagnet is energized.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electronic overload relay. [Background technology]

[0002] The following Patent Document 1 discloses an electronic overload relay configured to switch a contact mechanism between a trip position and a reset position using a permanent magnet and a coil that generate magnetic flux. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4738530 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional electronic overload relays use a configuration that uses one electromagnet, one permanent magnet, and four transistors for two-way control, or a configuration that uses two electromagnets, one permanent magnet, and two transistors for one-way control, which requires a large number of parts and makes it difficult to reduce cost and size. [Means for solving the problem]

[0005] An electronic overload relay according to one embodiment includes a contact mechanism that can be switched between a steady state and a tripped state, an electromagnet having a movable shaft that moves axially when energized, a slider that moves axially in conjunction with the movable shaft when energized, and a driven member that alternately switches the stop position of the slider after it moves axially between a first stop position corresponding to the steady state and a second stop position corresponding to the tripped state each time the electromagnet is energized. [Effects of the Invention]

[0006] According to an electronic overload relay according to one embodiment, the number of parts used for switching the contact mechanism can be reduced, thereby realizing lower costs and a smaller size. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of an electronic overload relay according to an embodiment of the present invention, seen from the front side; [Figure 2] 1 is a perspective view of an electronic overload relay according to an embodiment, seen from the bottom side; FIG. [Figure 3] 1 is an exploded perspective view of an electronic overload relay according to an embodiment, viewed from the bottom side; [Figure 4] FIG. 1 is a diagram illustrating a configuration of a contact switching mechanism included in an electronic overload relay according to an embodiment. [Figure 5] FIG. 1 is an external perspective view of a slider included in a contact switching mechanism according to an embodiment; [Figure 6] FIG. 1 is a diagram illustrating a configuration of a heart cam mechanism included in a contact switching mechanism according to an embodiment. [Figure 7] FIG. 10 is a diagram illustrating the operation of a contact switching mechanism according to an embodiment; [Figure 8] FIG. 10 is a diagram illustrating the operation of a contact switching mechanism according to an embodiment; [Figure 9] FIG. 10 is a diagram illustrating the operation of a contact switching mechanism according to an embodiment; [Figure 10] FIG. 10 is a diagram illustrating the operation of a contact switching mechanism according to an embodiment; [Figure 11] FIG. 1 is an external perspective view of a position sensor included in a contact switching mechanism according to an embodiment; [Figure 12] FIG. 10 is a diagram for explaining a method for detecting the position of a slider by a position sensor included in a contact switching mechanism according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment will be described with reference to the drawings.

[0009] (Schematic configuration of electronic overload relay 10)

[0010] Fig. 1 is an external perspective view of an electronic overload relay 10 according to an embodiment, as viewed from the front side (positive side of the X-axis). Fig. 2 is an external perspective view of an electronic overload relay 10 according to an embodiment, as viewed from the bottom side (negative side of the Z-axis). Fig. 3 is an exploded perspective view of an electronic overload relay 10 according to an embodiment, as viewed from the bottom side (negative side of the Z-axis).

[0011] In the following description, for convenience, the X-axis direction is the front-to-back direction, the Y-axis direction is the left-to-right direction, and the Z-axis direction is the up-to-down direction, where the positive X-axis direction is the front, the positive Y-axis direction is the right, and the positive Z-axis direction is the up.

[0012] For example, the electronic overload relay 10 is used by connecting it to a motor (not shown) and an electromagnetic contactor (not shown) provided in the motor's load circuit in order to prevent the motor from burning out due to a continued overload condition of the motor.

[0013] The electronic overload relay 10 has a trip function in which the contact mechanism 20 (see FIG. 4) switches to a tripped state when an overcurrent flows through the load, a manual reset function in which the contact mechanism 20 manually returns from the tripped state to a steady state, and an automatic reset function in which the contact mechanism 20 automatically returns from the tripped state to the steady state after a predetermined time has elapsed.

[0014] For example, electronic overload relay 10 takes in the load current of a motor using overcurrent detector 15, and when the taken-in load current exceeds a set value, overcurrent detector 15 passes a drive current to electromagnet 101 to drive electromagnet 101, thereby performing a tripping operation that switches contact mechanism 20 to a tripped state. Specifically, in electronic overload relay 10, when overcurrent detector 15 takes in the load current of the motor, control circuit 13 is driven by the load current, and control circuit 13 detects, judges, and issues commands regarding the load current.

[0015] When the contact mechanism 20 is in a tripped state, the electronic overload relay 10 transmits a first state signal to the electromagnetic contactor to cause the electromagnetic contactor to perform an interruption operation, thereby interrupting the load circuit of the motor.

[0016] After that, when a predetermined time has elapsed, the electronic overload relay 10 performs an automatic reset operation by passing a drive current through the electromagnet 101 to switch the contact mechanism 20 to the steady state by using the automatic reset function.

[0017] Alternatively, the electronic overload relay 10 performs a manual reset operation by using a manual reset function to mechanically switch the contact mechanism 20 to the steady state before the predetermined time has elapsed.

[0018] When the contact mechanism 20 is in a steady state, the electronic overload relay 10 can connect the load circuit of the motor by sending a second state signal to the electromagnetic contactor to cause the electromagnetic contactor to perform a connecting operation.

[0019] As shown in FIG. 3, the electronic overload relay 10 includes a case 11, a cover 12, a control circuit 13, an overcurrent detector 15, a contact mechanism 20, and a contact switching mechanism 100.

[0020] Case 11 is a container-like member having a hollow structure. For example, case 11 is formed using an insulating material such as synthetic resin. Case 11 has an open bottom, and a resin cover 12 is attached to the bottom to close the bottom.

[0021] The control circuit 13 is provided within the case 11 and is configured by mounting a plurality of electronic components on a circuit board. The control circuit 13 realizes various functions (e.g., an automatic reset function) of the electronic overload relay 10. In addition, a position sensor 104 is provided on the circuit board 13A of the control circuit 13 to detect the stop position of the slider 102 provided in the contact switching mechanism 100.

[0022] Overcurrent detector 15 receives the load current of the motor. The load current received by overcurrent detector 15 drives control circuit 13. When the received load current exceeds a set value, control circuit 13 supplies a drive current to electromagnet 101 to drive electromagnet 101.

[0023] The contact switching mechanism 100 is provided in the case 11 and switches the contact mechanism 20 between a trip state and a steady state.

[0024] (Configuration of contact switching mechanism 100) Fig. 4 is a diagram showing the configuration of a contact switching mechanism 100 provided in an electronic overload relay 10 according to one embodiment. Fig. 4(a) shows the electronic overload relay 10 from the bottom side (negative side of the Z axis) without the cover 12 and control circuit 13. Fig. 4(b) shows a cross section of the electronic overload relay 10 from the bottom side (negative side of the Z axis). Fig. 5 is an external perspective view of a slider 102 provided in a contact switching mechanism 100 according to one embodiment.

[0025] As shown in FIG. 4, electronic overload relay 10 has contact mechanism 20, contact switching mechanism 100, and manual reset mechanism 120 provided in case 11.

[0026] <<Contact mechanism 20>> 4(b), the contact mechanism 20 has a first movable contactor 21, a first fixed contactor 22, a second movable contactor 23, and a second fixed contactor 24. The first movable contactor 21 and the first fixed contactor 22 form a first contact 20A. The second movable contactor 23 and the second fixed contactor 24 form a second contact 20B.

[0027] In the contact mechanism 20, in a steady state, the first movable contact 21A of the first movable contactor 21 abuts against the first fixed contact 22A of the first fixed contactor 22, so that the first contact 20A is in a closed state.

[0028] In addition, in the contact mechanism 20, in the steady state, the second movable contact 23A of the second movable contactor 23 is separated from the second fixed contact 24A of the second fixed contactor 24, so that the second contact 20B is in the open state.

[0029] On the other hand, in the contact mechanism 20, in the tripped state, the first movable contact 21A of the first movable contactor 21 is separated from the first fixed contact 22A of the first fixed contactor 22, so that the first contact 20A is in the open state.

[0030] In addition, in the contact mechanism 20, in the tripped state, the second movable contact 23A of the second movable contactor 23 abuts against the second fixed contact 24A of the second fixed contactor 24, so that the second contact 20B is in the closed state.

[0031] <<Contact point switching mechanism 100>> As shown in FIG. 4( a ), the contact switching mechanism 100 includes an electromagnet 101 , a slider 102 , and a driven member 103 .

[0032] <Electromagnet 101> The electromagnet 101 has a main body 101A, a movable shaft 101B, a plate-like member 101D (armature), and a coil spring 101C.

[0033] The main body 101A is configured to have an electromagnetic coil and the like, and when energized, generates a magnetic force for moving the movable shaft 101B in the axial direction of the central axis AX.

[0034] The movable shaft 101B has a shaft shape and is provided on the central axis AX, penetrating the center of the main body 101A. The movable shaft 101B is movable on the central axis AX in the axial direction of the central axis AX (Y-axis direction). For example, the movable shaft 101B is made of iron. The movable shaft 101B is movable to the right (positive direction of the Y-axis) by the magnetic force generated by the main body 101A.

[0035] The plate-like member 101D is a flat plate-like member provided at the left end (the end on the negative side of the Y axis) of the movable shaft 101B.

[0036] The coil spring 101C is provided between the left end (the end on the negative side of the Y axis) of the main body 101A and the plate-shaped member 101D so as to be expandable and contractible in the left-right direction (the Y axis direction). The coil spring 101C biases the plate-shaped member 101D and the movable shaft 101B to the left (the negative direction of the Y axis).

[0037] <Slider 102> The slider 102 is a resin member that is movable in the left-right direction (Y-axis direction). The slider 102 is connected to the contact mechanism 20, and by moving in the left-right direction (Y-axis direction), the contact mechanism 20 can be switched between a steady state and a tripped state. As shown in FIGS. 4 and 5 , the slider 102 has a fitting portion 102A on the central axis AX. The slider 102 is connected to the movable shaft 101B by fitting the tip end (the end on the positive side of the Y-axis) of the movable shaft 101B into the fitting portion 102A. As a result, when the electromagnet 101 is energized, the slider 102 moves in the axial direction of the movable shaft 101B (Y-axis direction) in conjunction with the movable shaft 101B. The slider 102 also has a cam groove 102B that constitutes a heart cam mechanism on the central axis AX. The cam groove 102B is provided to follow the hook portion 103A of the driven member 103. The slider 102 also has a protrusion 102C that protrudes downward (in the negative direction of the Z axis) on the central axis AX between the fitting portion 102A and the cam groove 102B. The protrusion 102C is provided so that the position sensor 104 can detect the stop position of the slider 102.

[0038] <Following member 103> The driven member 103 is a metallic rod-like member that is provided on the central axis AX and extends linearly along the central axis AX. Each time the electromagnet 101 is energized, the driven member 103 alternately switches the stop position of the slider 102 after it moves in the axial direction (Y-axis direction) between a first stop position corresponding to the steady state of the contact mechanism 20 and a second stop position corresponding to the tripped state of the contact mechanism 20.

[0039] Specifically, driven member 103 has a hook portion 103A at its tip, which is formed by bending upward (in the positive direction of the Z axis) at a substantially right angle. Hook portion 103A constitutes a heart cam mechanism. Each time electromagnet 101 is energized, hook portion 103A follows cam groove 102B of slider 102, so that driven member 103 alternates between a first stop position and a second stop position after slider 102 moves in the axial direction (Y axis direction).

[0040] <<Manual reset mechanism 120>> The manual reset mechanism 120 is provided to manually return the contact mechanism 20 from a tripped state to a steady state. The manual reset mechanism 120 has a reset button 121, a coil spring 122, and a push rod 123. A portion of the reset button 121 protrudes outside the case 11, and the reset button 121 can be pressed from outside the case 11.

[0041] When reset button 121 is pressed in the negative direction of the X axis, manual reset mechanism 120 moves push rod 123 in the negative direction of the X axis together with reset button 121, causing pressing portion 123A (an example of a "conversion means") provided at the tip of push rod 123 to press slider 102 and move slider 102 in the positive direction of the Y axis. Because pressing portion 123A of push rod 123 is inclined, pressing slider 102 with pressing portion 123A converts the moving force of reset button 121 in the negative direction of the X axis into a moving force of slider 102 in the positive direction of the Y axis, thereby moving slider 102 in the positive direction of the Y axis.

[0042] In this way, the manual reset mechanism 120 moves the slider 102 in the positive direction of the Y axis, thereby disengaging the hook portion 103A of the driven member 103 from the slider 102 and switching the stop position of the slider 102 from the second stop position to the first stop position, thereby manually returning the contact mechanism 20 from the tripped state to the steady state.

[0043] The reset button 121 is biased in the positive direction of the X-axis by a coil spring 122. This allows the reset button 121 to automatically move in the positive direction of the X-axis and return to its initial position when released from the pressing operation.

[0044] (Heart cam mechanism configuration) 6A and 6B are diagrams showing the configuration of a heart cam mechanism included in a contact switching mechanism 100 according to one embodiment. Fig. 6A is a plan view of the heart cam mechanism as viewed from the negative side of the Z axis. Fig. 6B is a perspective view of the heart cam mechanism as viewed from the negative side of the Z axis.

[0045] 6, the heart cam mechanism included in the contact switching mechanism 100 according to one embodiment is configured to have a cam groove 102B of the slider 102 and a hook portion 103A of the driven member 103. The heart cam mechanism alternately switches the stop position of the slider 102 after it moves in the axial direction (Y-axis direction) between a first stop position and a second stop position as the hook portion 103A follows the cam groove 102B.

[0046] 6, the cam groove 102B has a heart-shaped groove recessed toward the positive side of the Z axis. The cam groove 102B is configured to have a first groove portion 102Ba, a second groove portion 102Bb, and a third groove portion 102Bc.

[0047] The first groove portion 102Ba is a portion that extends in the negative Y-axis direction while increasing the overall width of the cam groove 102B in the X-axis direction, starting from the initial position P1 and ending at the first movement position P2.

[0048] The second groove portion 102Bb is a portion that extends in a V-shape in the negative direction of the X axis, starting from the first movement position P2 and ending at the third movement position P4. A valley-shaped second movement position P3 is provided at the middle position of the second groove portion 102Bb.

[0049] The third groove portion 102Bc is a portion that extends in the positive direction of the Y axis while reducing the overall width of the cam groove 102B in the X axis direction, starting from the third movement position P4 and ending at the initial position P1.

[0050] As shown in FIG. 6, when the slider 102 is stopped at the first stop position corresponding to the steady state of the contact mechanism 20, the hook portion 103A of the driven member 103 is located at the initial position P1, which is the starting point of the first groove portion 102Ba.

[0051] Then, when the electromagnet 101 is energized for the first time, the slider 102 moves in the positive direction of the Y-axis, and the hook portion 103A of the driven member 103 moves in the negative direction of the Y-axis within the first groove portion 102Ba, overcomes the step S1 provided in the first groove portion 102Ba, and is positioned at the first movement position P2.

[0052] Furthermore, when the first energization of electromagnet 101 is released, slider 102 moves in the negative Y-axis direction due to the biasing force of coil spring 101C, and hook portion 103A of driven member 103 moves in the negative X-axis direction within second groove portion 102Bb, overcomes step S2 provided in second groove portion 102Bb, and engages with second movement position P3, which is the intermediate position of the valley bottom of second groove portion 102Bb. This stops the movement of slider 102 in the negative Y-axis direction, and slider 102 stops at a second stop position that corresponds to the tripped state of contact mechanism 20.

[0053] Next, when the electromagnet 101 is energized for the second time, the slider 102 moves in the positive direction of the Y-axis, and the hook portion 103A of the driven member 103 moves in the negative direction of the X-axis within the second groove portion 102Bb, overcomes the step S3 provided in the second groove portion 102Bb, and is positioned at the third movement position P4.

[0054] Then, when the second de-energization of electromagnet 101 is released, slider 102 moves in the negative direction of the Y-axis due to the biasing force of coil spring 101C, and hook portion 103A of driven member 103 moves in the positive direction of the Y-axis within third groove portion 102Bc, overcomes step S4 provided in third groove portion 102Bc, and is positioned at initial position P1. As a result, slider 102 moves the maximum amount in the negative direction of the Y-axis and stops at a first stop position that corresponds to the steady state of contact mechanism 20.

[0055] In this way, the heart cam mechanism provided in the contact switching mechanism 100 of one embodiment alternates the stop position of the hook portion 103A of the driven member 103 between the initial position P1 and the second movement position P3 each time the electromagnet 101 is energized, thereby allowing the stop position of the slider 102 after movement in the axial direction (Y-axis direction) to alternate between the first stop position and the second stop position.

[0056] In addition, the heart cam mechanism provided in the contact switching mechanism 100 according to one embodiment has steps S1 to S4 provided in the cam groove 102B so that the hook portion 103A of the driven member 103 does not move in the reverse direction within the cam groove 102B.

[0057] (Operation of contact switching mechanism 100) 7 to 10 are diagrams illustrating the operation of the contact switching mechanism 100 according to one embodiment.

[0058] (Initial state) FIG. 7 shows the state of the contact mechanism 20 and the contact switching mechanism 100 when the contact switching mechanism 100 is in the initial state.

[0059] 7, in the initial state of the contact switching mechanism 100, the electromagnet 101 is not energized and the slider 102 is stopped at the first stop position (the position where it has moved the maximum amount to the negative side of the Y axis). At this time, the hook portion 103A of the driven member 103 is located at the initial position P1 in the cam groove 102B of the slider 102.

[0060] As shown in Figure 7, when the contact switching mechanism 100 is in the initial state, the first movable contact 21A of the first movable contactor 21 abuts against the first fixed contact 22A of the first fixed contactor 22, so that the first contact 20A of the contact mechanism 20 is in a closed state.

[0061] Also, as shown in Figure 7, when the contact switching mechanism 100 is in the initial state, the slider 102 is stopped at the first stop position, so that the second movable contact 23A of the second movable contactor 23 is separated from the second fixed contact 24A of the second fixed contactor 24, and the second contact 20B of the contact mechanism 20 is in the open state.

[0062] That is, when the contact switching mechanism 100 is in the initial state, the contact mechanism 20 is in the steady state.

[0063] As shown in FIG. 7, when the contact switching mechanism 100 is in the initial state, the indicator 14 is in the display state.

[0064] (First energized state) FIG. 8 shows the state of the contact mechanism 20 and the contact switching mechanism 100 when the contact switching mechanism 100 is in the first energized state (when the electromagnet 101 is energized for the first time).

[0065] 8, in the first current-carrying state of the contact switching mechanism 100, current is passed through the electromagnet 101 for the first time, and the magnetic force generated by the electromagnet 101 moves the movable shaft 101B of the electromagnet 101 in the positive direction of the Y-axis, and in conjunction with this, the slider 102 moves in the positive direction of the Y-axis. At this time, the hook portion 103A of the driven member 103 moves within the cam groove 102B of the slider 102 from the initial position P1 to the first movement position P2 via the first groove portion 102Ba.

[0066] As shown in Figure 8, when the contact switching mechanism 100 is in the first current-carrying state, as the slider 102 moves in the positive direction of the Y axis from the first stop position, the first movable contact 21A of the first movable contactor 21 moves away from the first fixed contact 22A of the first fixed contactor 22, and the first contact 20A of the contact mechanism 20 enters the open state.

[0067] Also, as shown in Figure 8, when the contact switching mechanism 100 is in the first current-carrying state, the slider 102 moves in the positive direction of the Y axis from the first stop position, and the second movable contact 23A of the second movable contactor 23 abuts against the second fixed contact 24A of the second fixed contactor 24, causing the second contact 20B of the contact mechanism 20 to be in the closed state.

[0068] That is, when the contact switching mechanism 100 is in the first energized state, the contact mechanism 20 is in the tripped state.

[0069] As shown in FIG. 8, when the contact switching mechanism 100 is in the first energized state, the slider 102 can move in the positive direction of the Y axis to rotate the display 14 and place the display 14 in a non-display state.

[0070] (First de-energized state) FIG. 9 shows the state of contact mechanism 20 and contact switching mechanism 100 when contact switching mechanism 100 is in the first de-energized state (when electromagnet 101 is de-energized for the first time).

[0071] 9, in the contact switching mechanism 100, when the electromagnet 101 is de-energized for the first time in the first de-energized state, the movable shaft 101B of the electromagnet 101 moves in the negative direction of the Y axis due to the biasing force of the coil spring 101C, and in conjunction with this, the slider 102 moves in the negative direction of the Y axis. At this time, the hook portion 103A of the driven member 103 moves in the cam groove 102B of the slider 102 from the first movement position P2 through the second groove portion 102Bb to the second movement position P3, and is stopped at the second movement position P3. As a result, the slider 102 moves slightly in the negative direction of the Y axis and stops at the second stop position.

[0072] As shown in FIG. 9, when the contact switching mechanism 100 is in the first de-energized state, the slider 102 stops at the second stop position, so that the first contact 20A of the contact mechanism 20 maintains an open state and the second contact 20B maintains a closed state.

[0073] That is, when the contact switching mechanism 100 is in the first de-energized state, the contact mechanism 20 maintains the tripped state.

[0074] (Reset operation process) FIG. 10 shows the state of contact mechanism 20 and contact switching mechanism 100 when contact switching mechanism 100 is in the process of resetting (when reset operation of reset button 121 provided in manual reset mechanism 120 is performed).

[0075] As shown in Figure 10, when the reset operation of the reset button 121 is performed from the first de-energized state shown in Figure 9, the slider 102 is pressed by the pressing portion 123A of the push rod 123 provided in the manual reset mechanism 120, forcing the slider 102 to move in the positive direction of the Y axis.

[0076] As a result, the hook portion 103A of the driven member 103 moves within the cam groove 102B of the slider 102 from the second movement position P3 to the third movement position P4 via the second groove portion 102Bb.

[0077] As shown in FIG. 10, when the contact switching mechanism 100 is in the process of resetting, the slider 102 moves in the positive direction of the Y axis from the second stop position, so that the first contact 20A of the contact mechanism 20 maintains an open state and the second contact 20B maintains a closed state.

[0078] That is, when the contact switching mechanism 100 is in the process of resetting, the contact mechanism 20 maintains the tripped state.

[0079] (Reset operation released state) When the contact switching mechanism 100 is in the reset operation release state (when the reset operation of the reset button 121 is released), the contact switching mechanism 100 returns to the initial state shown in FIG.

[0080] Specifically, when contact switching mechanism 100 is in the reset operation release state, the pressure from push rod 123 is released, causing movable shaft 101B of electromagnet 101 to move in the negative direction of the Y axis due to the biasing force from coil spring 101C, and slider 102 moves in the negative direction of the Y axis in conjunction with this. At this time, hook portion 103A of driven member 103 moves within cam groove 102B of slider 102 from third movement position P4 to initial position P1 via third groove portion 102Bc. As a result, contact switching mechanism 100 returns to the initial state shown in FIG. 7, and slider 102 stops at the first stop position.

[0081] Then, as shown in Figure 7, when the contact switching mechanism 100 returns to the initial state shown in Figure 7, the first movable contact 21A of the first movable contactor 21 abuts against the first fixed contact 22A of the first fixed contactor 22, causing the first contact 20A of the contact mechanism 20 to be in a closed state.

[0082] Also, as shown in Figure 7, when the contact switching mechanism 100 returns to the initial state shown in Figure 7, the second movable contact 23A of the second movable contactor 23 of the contact mechanism 20 separates from the second fixed contact 24A of the second fixed contactor 24, causing the second contact 20B to be in an open state.

[0083] That is, when the contact switching mechanism 100 is released from the reset operation and returns to the initial state, the contact mechanism 20 returns to the steady state.

[0084] When the contact switching mechanism 100 returns to the initial state, the slider 102 moves in the negative Y-axis direction, thereby rotating the display 14 in the reverse direction and setting the display 14 to the display state.

[0085] (Automatic recovery function) In addition, the contact switching mechanism 100 can also return the contact mechanism 20 to the steady state by entering the second current-carrying state and the second current-released state (i.e., automatic return function) instead of the reset operation state and the reset operation release state (i.e., manual return function).

[0086] Specifically, the contact switching mechanism 100 enters the second energized state when a predetermined time has elapsed from the first de-energized state shown in FIG. 9 and the electromagnet 101 is energized for the second time using the power stored in the capacitor 16 (see FIG. 3) during normal operation.

[0087] In the contact switching mechanism 100, when the electromagnet 101 is energized for the second time in the second energized state, the movable shaft 101B of the electromagnet 101 moves in the positive direction of the Y-axis due to the magnetic force generated by the electromagnet 101, and in conjunction with this, the slider 102 moves in the positive direction of the Y-axis. At this time, the hook portion 103A of the driven member 103 moves within the cam groove 102B of the slider 102 from the second movement position P3 to the third movement position P4 via the second groove portion 102Bb.

[0088] When the contact switching mechanism 100 is in the second energized state, the slider 102 moves in the positive direction of the Y axis from the second stop position, so that the first contact 20A of the contact mechanism 20 maintains an open state and the second contact 20B maintains a closed state.

[0089] That is, when the contact switching mechanism 100 is in the second conductive state, the contact mechanism 20 maintains the tripped state.

[0090] Furthermore, when the electromagnet 101 is de-energized for the second time, the contact switching mechanism 100 enters the second de-energized state and returns to the initial state shown in FIG.

[0091] Specifically, when the electromagnet 101 is de-energized for the second time in the second de-energized state, the movable shaft 101B of the electromagnet 101 moves in the negative direction of the Y axis due to the biasing force of the coil spring 101C, and in conjunction with this, the slider 102 moves in the negative direction of the Y axis. At this time, the hook portion 103A of the driven member 103 moves within the cam groove 102B of the slider 102 from the third movement position P4 to the initial position P1 via the third groove portion 102Bc. This returns the contact switching mechanism 100 to the initial state shown in FIG. 7, and the slider 102 stops at the first stop position.

[0092] Then, as shown in Figure 7, when the contact switching mechanism 100 returns to the initial state shown in Figure 7, the first movable contact 21A of the first movable contactor 21 abuts against the first fixed contact 22A of the first fixed contactor 22, causing the first contact 20A of the contact mechanism 20 to be in a closed state.

[0093] Also, as shown in Figure 7, when the contact switching mechanism 100 returns to the initial state shown in Figure 7, the second movable contact 23A of the second movable contactor 23 of the contact mechanism 20 separates from the second fixed contact 24A of the second fixed contactor 24, causing the second contact 20B to be in an open state.

[0094] That is, when the contact switching mechanism 100 is in the second de-energized state and returns to the initial state, the contact mechanism 20 returns to the steady state.

[0095] (Detection means) Fig. 11 is an external perspective view of the position sensor 104 included in the contact switching mechanism 100 according to one embodiment. Fig. 12 is a diagram for explaining a method for detecting the position of the slider 102 by the position sensor 104 included in the contact switching mechanism 100 according to one embodiment.

[0096] The contact switching mechanism 100 according to one embodiment includes a position sensor 104 as an example of a "detection means" that detects the position of the slider 102. As shown in Fig. 11, the position sensor 104 has a recess 104C between opposing wall portions 104A and 104B.

[0097] As shown in FIG. 12, the position sensor 104 is mounted on the circuit board 13A of the control circuit 13 so that the protrusion 102C of the slider 102 can pass through the recess 104C.

[0098] 12(a), when the slider 102 is stopped at the first stop position corresponding to the steady state of the contact mechanism 20, the protrusion 102C of the slider 102 is located within the recess 104C of the position sensor 104. As a result, the position sensor 104 can detect that the slider 102 is stopped at the first stop position because the detection medium (for example, light) propagating between the wall 104A and the wall 104B is blocked by the protrusion 102C.

[0099] 12(b), when the slider 102 is stopped at the second stop position corresponding to the steady state of the contact mechanism 20, the protrusion 102C of the slider 102 is located outside (on the positive Y-axis side) the recess 104C of the position sensor 104. This allows the position sensor 104 to detect that the slider 102 is stopped at the second stop position because the detection medium (for example, light) propagating between the wall 104A and the wall 104B is no longer blocked by the protrusion 102C.

[0100] In one embodiment, the contact switching mechanism 100 can detect the stop position of the slider 102 using the position sensor 104, so that even if the contact mechanism 20 is returned to the steady state by the manual return function, it can detect that the contact mechanism 20 has returned to the steady state.

[0101] (effect) As described above, the electronic overload relay 10 according to one embodiment comprises a contact mechanism 20 switchable between a steady state and a tripped state, an electromagnet 101 having a movable shaft 101B that moves axially when energized, a slider 102 that moves axially in conjunction with the movable shaft 101B when energized, and a driven member 103 that alternately switches the stop position of the slider 102 after it moves axially between a first stop position corresponding to the steady state and a second stop position corresponding to the tripped state each time the electromagnet 101 is energized.

[0102] As a result, the electronic overload relay 10 of one embodiment can switch the contact mechanism 20 between a steady state and a tripped state using a single electromagnet without using a permanent magnet, thereby reducing the number of parts used to switch the contact mechanism 20 and thereby achieving lower costs and smaller size.

[0103] Furthermore, since the electronic overload relay 10 according to one embodiment does not require a permanent magnet, it is possible to prevent latching failures caused by a decrease in magnetic force at low temperatures.

[0104] Furthermore, in the electronic overload relay 10 according to one embodiment, the slider 102 has a cam groove 102B that constitutes a heart cam mechanism, and the driven member 103 has a hook portion 103A that constitutes the heart cam mechanism at its tip, and each time the electromagnet 101 is energized, the hook portion 103A follows the cam groove 102B, thereby alternately switching the stop position of the slider 102 after it moves axially between a first stop position and a second stop position.

[0105] As a result, in one embodiment of the electronic overload relay 10, the cam groove 102B and the hook portion 103A can switch the contact mechanism 20 between a steady state and a tripped state, thereby reducing the number of parts used to switch the contact mechanism 20 and thereby achieving lower costs and smaller size.

[0106] The electronic overload relay 10 according to one embodiment also includes a manual reset mechanism 120 for manually restoring the contact mechanism 20 from the tripped state to the steady state.

[0107] As a result, the electronic overload relay 10 according to one embodiment can manually return the contact mechanism 20 from the tripped state to the steady state without energizing the electromagnet 101.

[0108] The electronic overload relay 10 according to one embodiment also includes a position sensor 104 that detects the stop position of the slider 102 in the axial direction.

[0109] As a result, the contact switching mechanism 100 of one embodiment can detect the stopping position of the slider 102 using the position sensor 104, and therefore can detect that the contact mechanism 20 has returned to the steady state even if the contact mechanism 20 has returned to the steady state by the manual reset mechanism 120.

[0110] Furthermore, in the electronic overload relay 10 according to one embodiment, the manual reset mechanism 120 has a reset button 121, and by pressing the reset button 121, the slider 102 is moved in the axial direction, and the stop position of the slider 102 is switched from the second stop position to the first stop position, thereby manually resetting the contact mechanism 20.

[0111] As a result, electronic overload relay 10 according to one embodiment can realize manual reset mechanism 120 with a relatively simple configuration in which reset button 121 is used to move slider 102 in the axial direction.

[0112] In addition, in the electronic overload relay 10 according to one embodiment, the manual reset mechanism 120 has a pressing portion 123A that converts the axial moving force of the reset button 121, which is generated when the reset button 121 is pressed, into the axial moving force of the slider 102.

[0113] As a result, in the electronic overload relay 10 according to one embodiment, the reset button 121 can be disposed so that the direction in which the reset button 121 is pressed is perpendicular to the direction in which the slider 102 moves.

[0114] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0115] 10 Electronic Overload Relay 11 cases 12 Cover 13 Control circuit 13A circuit board 14 Display 15 Overcurrent detector 20 Contact mechanism 20A first contact 20B 2nd contact 21 First moving contact 22 1st fixed contact 23 Second moving contact 24 2nd fixed contact 100 Contact switching mechanism 101 Electromagnet 101A main body 101B Movable axis 101C coil spring 101D Plate-shaped member 102 Slider 102A Mating part 102B Cam groove 102Ba First Groove 102Bb Second groove 102Bc 3rd groove 102C Protrusion 103 Follower member 103A Hook part 104 Position Sensor 104A Wall section 104B Wall section 104C Recess 120 Manual reset mechanism 121 Reset button 122 coil spring 123 Push rod 123A Pressing part (conversion means) AX center axis P1 initial position P2 1st movement position P3 2nd movement position P4 3rd movement position

Claims

1. a contact mechanism switchable between a steady state and a trip state; an electromagnet having a movable shaft that moves in an axial direction when energized; a slider that moves in the axial direction in conjunction with the movable shaft when energized; a driven member that alternately switches a stop position of the slider after the slider has moved in the axial direction between a first stop position corresponding to the steady state and a second stop position corresponding to the trip state every time the electromagnet is energized; An electronic overload relay comprising:

2. The slider includes: It has a cam groove that forms a heart cam mechanism, The driven member is The slider has a hook portion at its tip that constitutes the heart cam mechanism, and the hook portion moves along the cam groove each time the electromagnet is energized, thereby alternately switching the stop position of the slider after movement in the axial direction between the first stop position and the second stop position.

2. The electronic overload relay of claim 1.

3. a manual reset mechanism for manually returning the contact mechanism from the tripped state to the steady state; 3. An electronic overload relay according to claim 2.

4. A detection means for detecting a stop position of the slider in the axial direction is provided.

4. An electronic overload relay according to claim 3.

5. The manual reset mechanism includes: Has a reset button, When the reset button is pressed, the slider is moved in the axial direction, and the stop position of the slider is switched from the second stop position to the first stop position, thereby manually resetting the contact mechanism.

5. An electronic overload relay according to claim 4.

6. The manual reset mechanism includes: a conversion means for converting the axial moving force of the reset button, which is generated by the pressing operation, into the axial moving force of the slider; 6. An electronic overload relay according to claim 5.

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