KR19980032130A - Reverse spring contact switchgear and thermal overload relay - Google Patents

Abstract

A contact opening / closing mechanism mounted on a thermal overload relay, the reverse spring mechanism of which the reverse spring mechanism is made of one component that is simple to manufacture and assemble and which is improved to obtain a stable reversal point is provided. The pair of inverted spring contact opening and closing mechanisms 6 combined with a bimetallic heating element 2 operating in response to an overload current of the pair of outer side pieces 7a and center pieces 7b left and right by one sheet of spring material A reverse leaf spring 7 formed by punching and having a curved spring portion 7c formed on each central piece, a support arm 8 supporting the leading edge of the outer each piece so as to be free of rotation, and a central each piece Bimetal 2a of the thermal element based on the overload current, comprising a support arm 9 for holding the tip edge of each piece while applying a tension force to the spring part and fixing the upper and lower contact points 4a and the upper contact point 4b. Side Via a shifter (2c) and the release lever 5 is transmitted to the inverted plate spring 7, and switches the contact point with the reversing operation.

Description

Reverse spring contact switchgear and thermal overload relay

The present invention provides a reversing spring contact opening and closing mechanism for opening and closing a movable contact by a snap action of a reversing spring mechanism that operates according to an operation of a release lever, and a bimetallic heat that operates in response to an overload current. A thermal overload relay incorporating a device into a reversal spring contact opening and closing mechanism.

As is known, an electromagnetic contactor for driving control connected to a feeding circuit of an electric motor is provided with a thermal overload relay described at the outset for overload protection.

Fig. 4 is a block diagram of a thermal overload relay employing a conventional inverted spring contact opening and closing mechanism disclosed in Japanese Patent Laid-Open No. 2-86024. In the drawing, 1 is a resin case of a relay. In this case, a bimetal thermal element 2, an inversion spring mechanism 3 and a contact mechanism 4 which operate in response to an overload current of the main circuit (for example, a power supply circuit of an electric motor) are incorporated.

Here, the thermal element 2 has a bimetal 2a (only one phase is shown in Fig. 2, but in a three-phase circuit, three bimetals corresponding to each phase have a load current of the main circuit). A heater 2b passing through is recommended, and one end of the shifter 2c connected to the tip of the bimetal 2a is positioned opposite to the seesaw release lever 5. .

On the other hand, the reverse spring mechanism 3 is the same as the reverse leaf spring 3a and the reverse leaf spring 3a formed by pressing a thin metal spring material into the shape shown in Figs. 5A and 5B. The metal leaf spring is bent in a U-shape, and the reverse plate spring 3a is composed of a gun reverse drive spring 3b and a mounting substrate 3c, and the reverse drive spring 3b is slit-shaped at both ends thereof. The engagement hole is opened and interposed between the tip of the central leg piece 3d projecting in the window of the inverted leaf spring 3a and the claw of the window edge opposite thereto. And the reversal spring mechanism 3 forms the recessed groove 1a formed in the resin case 1 with the front-end | tip of the engagement piece 3e formed in the mounting board | substrate 3c as a point. In the end of the inverted leaf spring 3a. It is plugged into the contact mechanism 4 and embedded in the resin case. At this assembly position, the tip of the release lever 5 is opposed to the center square piece 3d. In addition, 3f adjusts the operating point. The screw 3g is a compression spring which pressurizes and holds the reverse spring 3a in the case.

Further, the contact mechanism 4 has a structure in which a normally closed contact 4a and a constantly open contact 4b are assembled to the slider 4c of the insulator, and the slider 4c is provided. Is slidably supported by the resin case 1, and the front end of the inverted leaf spring 3a is inserted into the groove hole opened at one end thereof, and is interconnected. In addition, 4d is a reset push button.

The operating principle of the thermal overload relay having such a configuration is well known, and in the normal state, the reverse leaf spring 3a of the reverse spring mechanism 3 is right on the right side by the repulsive force of the reverse drive spring 3b. Direction, and the contact mechanism 4 is maintained as shown in the drawing. On the other hand, the bimetal 2a is supplied to the heater 2b of the thermal element 2 by flowing a load current flowing through the main circuit. When an overload current flows in the main circuit here, the curvature of the bimetal 2a increases as indicated by the dotted line in the drawing, and the shifter 2c pushes the release lever 5 to the left. (5) swings clockwise and pushes the center leg piece 3d of the inverted leaf spring 3a to the right. Then, the point of engagement between the center leg piece 3d and the inversion drive spring 3b is the inverted leaf spring 3a. Dead point (d) When moving beyond the ead point to the right side of the leaf spring, the inversion leaf spring 3a is inverted to the left by the spring force of the driving spring 3b, and the snap action 4c of the contact mechanism 4 is operated by the snap action. Is rapidly driven to the left. In this way, the upper and lower contact points 4a are opened and the upper contact point 4b is closed so as to be inverted to output a cutoff command of the main circuit current to the outside. Based on this cutoff command, For example, the electromagnetic contactor connected to the main circuit is operated to cut off the overload current. After the main circuit current is blocked, the curvature of the bimetal 2a of the thermal element 2 is sufficiently returned, and then the reset push button 4d is pressed. ), The slider 4c of the contact mechanism 4 moves to the right, and it operates according to this, and the reverse spring mechanism 3 reverses to an initial state, and a relay is reset.

However, the conventional inverted contact opening and closing mechanism built in the thermal overload relay, in particular the inversion spring mechanism 3 for driving the contact, has the following problems in terms of operation characteristics and assembly properties.

That is, in the conventional inversion spring mechanism 3, it becomes the assembly structure which hanged and couple | bonded the inversion drive spring 3b bent in a U shape to the inversion leaf spring 3a. Therefore, at the time of inversion operation of the inversion spring mechanism 3 The sliding friction between the metal members is generated at the fitting engagement points A and B between the inverted leaf springs 3a and the both ends of the driving spring 3b. The operating characteristic of becomes unstable.

In addition, the reversing spring mechanism 3 is assembled with two parts, a reversing leaf spring 3a and a reversing driving spring 3b, and therefore, the driving spring 3b is coupled to the inverting leaf spring 3a in the assembling process. At this time, it is necessary to have a cumbersome work of hanging the leaf springs of the driving spring 3b to the engaging claws of the inverted leaf springs 3a while bending the leaf springs in a U-shape. In reality, this assembly work is dependent on manual labor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to solve the above problems, and the reverse spring contact opening and closing mechanism is improved so that the reverse spring mechanism is made of a single part that is simple to manufacture and assemble and that a stable reverse point is obtained. In addition, the present invention provides a thermal overload relay in which a bimetal thermal element operating in response to an overload current is combined with this contact opening and closing mechanism.

1 is a configuration diagram of a thermal overload relay according to an embodiment of the present invention, (a) is an assembly configuration of a reverse spring contact opening and closing mechanism incorporating a bimetal thermal element, (b) is a reverse spring contact opening and closing A diagram showing a state of inversion operation of the mechanism.

Fig. 2 is a detailed structural diagram of the inverted leaf spring in Fig. 1, (a) is a front view, and (b) is a side view.

3 is an external perspective view of the assembled state in which the inverted leaf spring of FIG. 2 is fixed to the support arm.

4 is a configuration diagram showing a main part of a thermal overload relay in the related art.

5 is a structural diagram of a reverse spring mechanism employed in a conventional contact opening and closing mechanism, wherein (a) is a front view and (b) is a side view.

* Description of the symbols for the main parts of the drawings *

2: thermal element

2a: bimetal

2b: heater

2c: shifter

4a: Normally closed contact

4b: Open contact

6: reverse spring contact opening and closing mechanism

7: inverted leaf spring

7e: connecting part of each side

8: first supporting arm

9: 2nd support arm

9a: Hanging groove

10: contact drive lever

In order to achieve the above object, the reverse spring contact opening and closing mechanism of the present invention shall be constituted as follows. That is, by punching three pieces each consisting of a pair of left and right outer pieces and a center piece in one thin film spring material ( punched) An inverted leaf spring formed in an indented shape, and a curved tension spring portion is bent on each center piece, and the inverted leaf spring swings freely at the leading edges of the left and right outer pieces. And a first supporting arm for supporting, a second supporting arm for fastening the leading edge of each of the pieces in a fixed position while applying tension to the springs of the central pieces, and a release lever disposed to face the central pieces. Each contact connecting base of the inverted leaf spring is used as a contact driver, and the contact is opened and closed by inverting the inverted leaf spring by pressing the release lever. And configured to.

According to the reversing spring type contact opening / closing mechanism of the above structure, the reversing spring mechanism is composed of a single leaf spring, so that a cumbersome assembling process in which two parts are combined like the conventional reversing spring mechanism is unnecessary, and the number of parts is small, The interior work of the product can be fully supported by automatic assembly without relying on manual work. Furthermore, since there is only one inverted leaf spring, there is no friction part during the inversion operation, and buckling in the inversion operation is performed. The reverse point is stable in comparison with the inverted spring mechanism of the conventional constitution, because it is not accompanied by buckled. In addition, the inverted spring contact opening / closing mechanism has various contact type relays which open and close the contact by snap action, or Applicable to the contact opening and closing mechanism of the switchgear.

Moreover, in the said reverse spring type contact opening / closing mechanism which becomes the structure of this invention, each part of a mechanism can be specifically comprised by the following forms.

1) The second support arm is provided with a plurality of stages of locking grooves for variably adjusting the tip locking positions of the center pieces, and makes it possible to adjust the operating points of the reverse spring mechanism.

2) The inverted leaf spring itself is used as a movable contact piece, and an upper or upper closed contact is attached to the connecting base of each piece to achieve compactness and compactness.

3) Engage the contact drive lever on the connecting base of each piece of inverted leaf spring to open and close the separately installed contact mechanism through the lever.

4) The side edges of the outer shells are bent into L-shapes to form reinforcing ribs, and the flexural stiffness of the shells is increased to prevent the outer shells from buckling with tensile force.

5) A rectangular window is opened at the tip of each central piece of the inverted leaf spring, the edge of the window is formed in an edge shape, and the rectangular window is second supported in a state in which tensile stress is applied to the tension spring portion formed on each central piece. It hangs on the engaging groove of the arm, and stably hangs each center piece to a predetermined point position.

6) The tension springs formed on each central part of the inverted leaf spring are formed wider than other parts, and the stress applied to the springs is relaxed to prevent the spring property from being lowered by creep or the like.

On the other hand, the thermal overload relay according to the present invention includes a bimetal thermal element that operates in response to the overload current of the main circuit, a shifter that transfers a displacement of the thermal element based on the overload current, to the inverting spring contact opening / closing mechanism. In combination with the shifter and the central pieces of the inverted leaf spring, combining a swing release lever for inverting the inverted leaf spring through the shifter by the displacement of the bimetal, and the bimetal of the thermal element based on the overload current. The displacement is transmitted to the inverting plate spring of the contact opening / closing mechanism through the shifter and the release lever, and outputs a shutoff command of the main circuit current in the opening / closing operation of the contact by the inversion operation of the inverting leaf spring.

In addition, in order to reduce the size and compactness of the thermal overload relay, an inverted leaf spring of the contact opening / closing mechanism in the above structure is used as a movable contactor, and an upper-closed contact is provided at each connecting portion, and the connecting portion is separately provided. There is a configuration in which the contact drive lever for driving the upper contact of the installation is connected.

Hereinafter, an embodiment of the present invention will be described with reference to the thermal overload relay with reference to Fig. 1 to Fig. 3. In addition, the same reference numerals are given to the same members corresponding to Fig. 4 in the drawings of the embodiments.

In FIG. 1, the thermal element 2 is the same as the conventional one shown in FIG. 4, and the freedom of the bimetal 2a with three heaters 2b provided corresponding to each phase of the main circuit (three phases) is attached. The shifter 2c is connected to the stage, and is opposed to the tip of the temperature compensation bimetal 5a coupled to the shiso release lever 5 so as to face the tip of the shifter 2c.

On the other hand, the reverse spring type contact opening / closing mechanism 6 according to the present invention, which is connected to the heating element 2 via the release lever 5, has a reverse leaf spring composed of one leaf spring whose detailed structure is later described ( 7), the first and second support arms 8 and 9 supporting the inverted leaf spring 7 and the upper and lower contact 4a in which the inverted leaf spring 7 itself is directly installed on the leaf spring as a movable contactor. ), An upper contact 4b separated from the inverted leaf spring 7 and arranged, and an L-shaped contact drive lever 10 having one end connected to the inverted leaf spring 7 so that the front end thereof is opposed to the upper contact 4b. ) And the release lever 5 described above. 11 and 12 are fixed contacts opposing the upper and closing contacts 4a and the upper contact 4b, respectively.

Here, as shown in Figs. 2A and 2B, the inverted leaf spring 7 is a pair of left and right outer pieces 7a and a long length by press working with a thin film leaf spring material. Three square pieces of the central square piece 7b are punched to form a "mountain" shape, and a middle portion of the central square piece 7b is formed with a curved tension spring portion 7c that is bent into a V shape. The tension spring portion 7c is formed such that its width dimension D is wider than the width of each piece d of the central piece 7b. The outer piece 7a is formed in the shape of a knife edge. On the other hand, a frame-shaped locking portion 7d having a rectangular window 7d-1 opened is formed at the tip of each central piece 7b, and the inner edge of the rectangular window 7d-1 is an outer corner piece 7a. The tip is machined into a knife edge type, as shown in Fig. 6). The outer corner pieces 7a also show side edges of the left and right corner pieces. As shown, the bending reinforcement ribs 7a-1 are formed in an L shape to increase the bending rigidity of the outer leg piece 7a. Further, the inverted leaf spring 7 is used as the movable contact piece, and the outer leg piece ( The upper and lower contact points 4a are coupled to each side connecting base portion 7e connecting 7a) and the central each piece 7b by a thermal caulking method or the like.

In addition, the inverted leaf spring 7 is hypothesized between the first and second support arms 8 and 9, as shown in Fig. 3, so as to be reversibly latched thereto. That is, the outer corner piece 7a has its front end. The edge is fixed to the V-shaped groove portion 8a of the first support arm 8 as a hinge of the swinging point so as to freely swing the edge. On the other hand, the central square piece 7b is a square piece for extending the tension spring portion 7c. Is applied to the V-shaped locking groove 9a formed on the second support arm 9 in which the rectangular window 7d-1 of the front end locking portion 7d is disposed on the lower side. It locks in the position displaced in the front-end direction and the front-end | tip point of each piece 7a. Moreover, in the support arm 9, the holding position of the center each piece 7b can be variably adjusted along the longitudinal direction of the arm, The groove portion 9a is formed in a sawtooth shape. The groove portions 9a of the plurality of adjustment stages are formed in the second support arm 9 as described above. Thus, the reversal point of the inverted leaf spring 7 is adjusted or assembled on the second support arm in a correlation with the assembly of the bimetal 2a, the shifter 2c and the release lever 5 of the heating element 2. The inversion point due to an error can be corrected.

In addition, in the mounting state where the inverted leaf spring 7 is interposed between the first and second support arms 8 and 9 as described above, the spring tension of the tension spring portion 7c and the first support arm 8 are established. The inverted leaf spring 7 stands up in a stable position with the spring drag of each piece tilting the inverted leaf spring 7 at a point where it is balanced. Thus, the inverted leaf spring 7 and the first supporting arm 8 ), When the parts of the second support arm 9 are unitized and assembled, even when the reverse spring mechanism 6 is incorporated in a case such as a thermal overload relay as described below, the assembly of the reverse spring mechanism is a single unit. It can be easily incorporated into the case. The tension spring portion 7c formed on the center piece 7b always generates stress due to tension, but the spring portion 7c is widely formed as described above. Relieves stress, spring force such as creep Prevent the degradation is achieved by upset long lifetime.

Next, the operation of the thermal overload relay formed by combining the inverted spring contact opening / closing mechanism 6 having the above-described configuration with the thermal element 2 will be described with reference to FIGS. 1A and 1B. In the steady state indicated by), the bimetal 2a of the heating element 2 is retracted at the position indicated by the solid line, and the release lever 5 is almost free. In this state, the inverted leaf spring 7 The tip edge of each piece 7a is tilted in the right direction by the spring force of the tension spring portion 7c formed on the central piece 7b as the swing point, and the upper and closing contact points 4a are closed and the open contact point 4b is opened. On the other hand, if an overcurrent flows through the main circuit (such as a power feeding circuit of an electric motor) and the bimetal 2a is largely curved as shown by the dotted line, the shifter 2c is greatly displaced in the direction of the arrow P, thereby releasing the release lever 5. By pressing it and rotating the lever counterclockwise. The front end of the lever 5 presses the center square piece 7b of the inverted leaf spring 7 to the left. Then, the center square piece 7b subjected to this pressing force resists the spring force of the tension spring portion 7c and the outer corner piece If the left side of the swing point of (7a) is exceeded, that is, the dead point of the inverted leaf spring 7 is exceeded, the inverted leaf spring 7 is inverted by the spring force of the tension spring portion 7c, and by the snap action, As shown in Fig. 1 (b), the front end of the outer leg piece 7a is tilted so as to fall to the point in the left direction. Accordingly, the upper and lower contact points 4a are opened, while the upper contact points 4b are in contact driving. The inverting operation is performed so as to be pressed and closed by the lever 10, and at the same time, the operation signal of the overload relay and the magnetic contactor connected to the main circuit are opened using the contact operation signal to cut off the overload current.

In addition, the reset button 4d (built in the resin case 1 of the relay as shown in Fig. 4) is pushed in a state where the bimetal 2a of the heating element 2 cools down and retracts to the normal position after the current interruption. If the inverted leaf spring 7 is pushed to the right forcibly, the inverted leaf spring 7 is inverted to return to the original state shown in Fig. 1A. In addition, as the reset method, the reset button 4d In addition to the reset method by manual operation, if the inversion stop position of the inverted leaf spring 7 due to the overload current is regulated by a stopper, the bimetal 2a returns to the normal state after the current interruption and the shifter 2c retreats. The automatic reset method which automatically returned to the initial position by the spring force of the inverted leaf spring 7 itself can also be adopted.

In addition, although the example which showed the small size and compactness of the contact opening / closing mechanism was shown in the example of illustration directly attaching the upper-closed contact 4a as the movable contact piece as the movable contact piece, the present invention is limited to this. For example, as shown in FIG. 4, the open / close contact mechanism of the thermal overload relay is detached from the inverting leaf spring 7 and built in the slider, and the contact mechanism is configured to be opened and closed by the inverting motion of the inverting leaf spring 7. Moreover, of course, the reverse spring contact opening and closing mechanism can be applied to various contact relays other than the thermal overload relay, or to the contact opening and closing mechanism of the switch.

As mentioned above, according to the structure of this invention, the following effects are exhibited.

1) The reversing leaf spring of the reversing spring type contact opening / closing mechanism is formed by punching and bending a sheet of thin spring material, and has a lower number of parts and is inexpensive compared to the reversing leaf spring mechanism composed of two parts as in the conventional configuration. In addition, it can be easily incorporated in assembly and relay, and can cope with automatic assembly as well. In addition, there is no sliding part between the parts as in the conventional reversal spring mechanism composed of two parts, and it is not a buckling reversal method. Since the curved spring portion formed in each center piece is configured to be inverted as a tension spring, the inversion operation point is not scattered and the operation characteristic is stabilized.

2) In addition, the thermal overload relay of the present invention configured by combining such a reverse spring contact opening and closing mechanism with a thermal element has fewer parts, smaller size, and compactness as compared with the conventional configuration, and facilitates automatic assembly of the product. In addition, stable operation characteristics can be obtained and reliability is further improved.

Claims (9)

In the reverse spring contact opening and closing mechanism for driving the movable contact to the open and close position by the snap action of the reverse spring mechanism that operates in accordance with the release lever, An inverted leaf spring formed by punching three pieces composed of a pair of left and right outer pieces and a center piece in a single leaf spring material to form a "mountain" shape, and bending a tension spring portion of a curved shape in the center piece; A first support arm for supporting the swing of the inverted leaf spring freely with the leading edges of the pair of left and right outer pieces as points; A second supporting arm which fixes the leading edge of each of the pieces in a fixed position while applying a tension force to the tension spring portion of the central piece; And a release lever disposed to face each of the central pieces, A reverse spring contact opening / closing mechanism, characterized in that the contact driving portion of each piece of the reverse leaf spring is used as a contact driving portion, and the contact is opened and closed by an inversion operation of the reverse leaf spring by the pressing operation of the release lever. The reverse spring contact opening / closing mechanism according to claim 1, wherein the second support arm is provided with a plurality of stages of engaging grooves for variably adjusting the front end engaging positions of the center pieces. The reverse spring contact opening / closing mechanism according to claim 1, wherein an upper contact or an upper closing contact is provided on each of the connecting base pieces as the movable contact spring piece as the movable contact piece. The reverse spring contact opening / closing mechanism according to claim 1, wherein a contact drive lever is coupled to each connecting base portion of the inverted leaf spring, and the contact mechanism separately opened through the lever is opened and closed. The reverse spring contact opening / closing mechanism according to claim 1, wherein the side edge of each piece is bent in an L-shape to form a reinforcing rib so as to increase the bending rigidity of the outer piece. The reverse spring type contact according to claim 1, wherein a rectangular window is opened at a tip of each central piece of the inverted leaf spring, an edge of the window is formed in an edge shape, and fixed to the locking groove of the second support arm. Switchgear. The reverse spring contact opening / closing mechanism according to claim 1, wherein a tension spring portion formed on each center piece of the reverse leaf spring is formed wider than other portions. A bimetal thermal element that operates in response to an overload current of the main circuit; Three pieces of left and right pairs of outer and central pieces are punched out to form a `` san '' shape by one sheet of spring material, and a curved spring portion is formed on each of the center pieces, and the leading edge of the outer pieces is formed first. An inverted leaf spring which is placed on the support arm as a point and fixed to the second supporting arm by fixing the leading edge of each center piece; A shifter transferring a displacement of the thermal element based on the overload current; A swinging release lever in linkage between the shifter and each central piece of the inverted leaf spring for inverting the inverted leaf spring through the shifter by the displacement of the bimetal; And a top open contact or a top closed contact opened and closed by an inversion operation of the inverted leaf spring. 9. The method according to claim 8, wherein a reverse contact spring of the contact opening / closing mechanism is used as a movable contact piece, and an upper-close contact is provided at each of the connecting portions, and a contact drive lever is connected to the connecting piece for driving the upper contact of a separate installation. Thermal overload relay.