JPS61200637A - Thermal overload relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an adjustment link device that adjusts the operating point of a reversing mechanism that is mainly linked to the displacement of a bimetal in a thermal overload relay in accordance with an electric current.

[Prior art and its problems]

As an example of this kind of conventional device, one shown in FIG. 5 is known. Although only a portion is shown in the figure, this thermal type overload relay is of the automatic and manual reset type, and inside the insulating case 1 there is a heating element for three phases inserted into the electric circuit on the right side (not shown). A wound main bimetal 2, a shifter 3 that is engaged with each of the free ends 2a of the main bimetal 2 and supported by a guide fit 1a of the case 1 so as to be movable in the direction of arrow P by the curvature of the main bimetal 2; an opening/closing mechanism 4 disposed in the case 1 so as to be able to engage with one end of the contact device 5;
and a return device 6, which is fixed when the contact device 5 is in automatic return mode and is freely operable in case of manual return mode, are housed as main components. The opening/closing mechanism 4 includes a release lever 8 that is pivotally supported on the inner wall of the case 1 at a point W via an adjustment link device 7 and engages with a reversing mechanism to be described later, and a release lever 8 that is integrated with the release lever 8 and has a free end that is connected to the tip of the shifter 3. An engageable temperature compensating bimetal 9, an adjusting link 10 whose one end constituting the adjusting link device 7 is coupled to the release lever 8 at point X and pivotally supported at the aforementioned point W, and the other end of the adjusting link 10 is It includes a cam lla of the adjustment dial 11 that engages, and a spring 12 that presses the other end of the adjustment link 10 against the cam lla. The contact device 5 is fixed to the case 1 by a movable plate 15 and a terminal 16 to which a normally open movable contact 13 and a drive plate 14 made of an insulator are attached, and a terminal 17 that can be connected to and separated from the normally open movable contact 13. A normally open fixed contact 18, a normally open movable contact driven by the operation of the movable plate 15 and fixed to the case 1 by a terminal 19, and a terminal 21 that can be connected to and separated from the normally closed movable contact I.
It is equipped with one point n of a normally closed measuring position fixed to the case 1. The reversing mechanism, which is a part of the contact device 5, is screwed onto a dual-speed movable plate 15 whose one end is swingably supported in a V-shaped groove 16a provided in the terminal 16, and between the movable plate 15 and the terminal 16. The contact opening/closing tension spring 5 is stretched between the adjustment screw U and rotates the movable plate 15 in reverse when its line of action crosses two points of the single-shaped groove 16a that supports the movable plate 15. There is. The contact device 5 is shown set to the automatic return type, and in the case of the manual return type, the operating rod of the return device 6 is pulled up to the position shown by the chain line to open the normally open side fixed contact n.
need to be pushed back.

The operation of the above configuration will be explained with reference to the principle diagrams shown in FIGS. 6 and 7. When the operating current i flows through the heating element wound around the main bimetal 2, the main bimetal 2 is bent by the heat generated by the heating element I, and the shifter 3 is moved in the direction of arrow P. As the shifter 3 moves, its tip pushes the free end of the temperature compensating bimetal 9 and rotates the integrated release lever 8 clockwise about the fulcrum X. 7 of the tension spring 5 of the reversing mechanism n when the release lever 8 is rotated. When the angle θ between the force direction Ps of the tension spring 5 and the movable plate 15 exceeds θ° (dead center), the movable plate 15 is reversed to the position shown by the dotted line. Further, when it is desired to change the operating current i, it is necessary to change the reversal position because the heat generated by the heating element and the amount of curvature of the main bimetal 2 change as the operating current i changes. In that case, turn the adjustment dial 11 to adjust the contact area Y between the cam lla and the other end of the 1llilF link 10.
By rotating the lever around the support AW, the release lever 8
The adjustment link 10 and the release lever 8 are moved to the position shown by the chain line by rotating the fulcrum X. At this time, the displacement dimension L1 of the contact portion Y and the displacement dimension L2 of the free end of the temperature compensating bimetal 9 are structured to change depending on the amount of curvature of the main bimetal 2. However, as is clear from the trajectory drawn by the adjustment lever 10 and the release lever 8, the point of action on the flap of the tension spring 5 at the tip of the release lever 8 moves by the distance L3, causing the movable plate 15 to move. The drawback was that the force exerted varied.

When the action point of the release lever 8 is set to the automatic return type shown in FIG. If the difference between the normally open side fixed contact 18 and the dead center when it is in the closed state is used as the hysteresis between operation and return, there is a drawback that a difference of δA and JB occurs as shown in the figure.

[Purpose of the invention]

An object of the present invention is to provide a gJIEIJ link device for a thermal overload relay, which eliminates the above-mentioned conventional drawbacks, reduces variations in driving force and hysteresis of a reversing mechanism due to changes in operating current, and improves accuracy. It is in.

[Key points of the invention]

The gist of the present invention is to achieve the above-mentioned object by providing a shifter that transmits the displacement of a bimetal based on an overcurrent, a release lever whose one end engages with the shifter and is rotated via the shifter by the displacement of the bimetal. an adjustment link connected to the release lever and rotatably supported and pressed by the cam of the adjustment dial; and an adjustment link connected to the release lever and a tension spring that is engaged with the release lever and that is rotated as the release lever rotates. In a thermal overload relay comprising a movable plate that reverses when the line of action exceeds a dead center, and a contact device that connects and separates as the movable plate reverses, the fulcrum of the adjustment link is locked on the fixed side of the tension spring. and the fulcrum of the movable plate, so that the engagement point of the release lever with the tension spring does not move even if the operating current is changed. .

[Embodiments of the invention]

1 to 3 are diagrams showing an embodiment of a thermal overload relay according to the present invention. In the figures, the same parts as those of the conventional device shown in FIG. I will explain with emphasis on. The difference between this embodiment and the conventional device is that the fulcrum W of the adjustment link 31 of the adjustment link device 7 connects to the fixed side locking groove 32a of the tension spring 6 of the reversing mechanism n via the fixed piece 32, and the movable plate That fulcrum groove 3
2b(Z) and both grooves 32a and 3.
2b. Next, a pin hole used to connect the adjustment link 31 and the release lever U of the opening/closing mechanism 4 and serving as the X point is arranged so as to be able to come into contact with the cam lla of the adjustment dial 11, and is placed between the adjustment link 31 and the inner wall of the case 1. It is pressed against the cam 111 by an attached spring I. And the engagement point of the release lever to that tension spring 5 is the adjustment link 31.
The structure of the fulcrum W is such that a through hole 31a is provided at both leg ends on the adjustment link 31 side, and a through hole 31a is fitted into the corresponding part of the fixed part so as to be able to swing freely. A projection 32C is provided. It goes without saying that the adjustment link 31 side may be a protrusion and the fixed piece side may be a through hole.

The operation of the above configuration will be explained in conjunction with the principle diagram of FIG. 4. When the main bimetal 2 is heated and curved by a heating element (not shown) and moves the shifter 3 in the direction of the arrow P, the tip of the shifter 3 pushes the free end of the temperature compensating bimetal 9 and releases the integrated release lever. Rotate clockwise around the fulcrum X. When the release lever U is rotated, its tip 34a pushes the flap of the tension spring 6 of the reversing mechanism, reversing the movable plate and bringing the contact device 5, only partially shown, into contact with and away from it. On the other hand, when changing the operating current,
By rotating the adjustment dial 11, the fulcrum X where the cam l1M and the pin mark come into contact is rotated around the fulcrum W of the adjustment link 31, and the temperature compensating bimetal 9 integrated with the release lever tool is rotated.
This will change the engagement position between the tip of the shifter 3 and the tip of the shifter 3. At this time, since the fulcrum W of the adjustment link 31 is located on the line connecting the fixed-side locking groove 32a of the tension spring 5 and the fulcrum groove 32b (Z) of the movable plate stem, and between the two, as shown in FIG. As shown in the figure, the amount of movement of the shifter 3 changes during operation, but
The pressing position of the tension spring 5, which is the tip 34a of the release lever M, does not change.

In this embodiment, the fulcrum X of the release lever is connected to the cam lla.
The fulcrum X is not limited to this, as long as it is on the axis of the adjustment link 31.

〔Effect of the invention〕

According to this invention, the rotation fulcrum of the adjustment link is provided on the line connecting the support point of the movable plate and the fixed side locking part of the tension spring of the reversing mechanism, and between the two, so that the rotation fulcrum of the adjustment link is provided as the y4 adjustment link rotates. By making sure that the engagement point of the release lever with the tension spring does not change, there is no change in the reversing operating force, and there is no change in the hysteresis between the operating point and the return point due to the adjustment current, resulting in good accuracy and stable heat. We can provide type overload relays.

[Brief explanation of drawings]

1 to 4 are diagrams showing an embodiment of the thermal overload relay according to the present invention, and FIG. 1 is a front view of the main parts before operation;
Figures 2 and 3 are perspective views of different main components, Figure 4 is a principle diagram, Figures 5 to 7 are diagrams showing an example of a conventional overload relay, and Figure 5 is after operation. Figure 6 is a front view of the main parts, Figure 6 is a principle diagram when set to manual return type, Figure 7 is
The figure is a principle diagram of the main parts when set to automatic return type. 2... Main bimetal, 3... Shifter, 5... Contact device, 11... Adjustment dial, lla... Cam, 5
...Tension spring, 31...Adjustment link, 31a...
Protrusion, 32a... fixed side locking groove, 32b... fulcrum groove, 32c... protrusion, oh... movable plate, ah... release 11 kettle dial No. 11! 1 Fig. 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1) A shifter that transmits the displacement of a bimetal based on an overcurrent, a release lever whose one end engages with the shifter and is rotated via the shifter by the displacement of the bimetal, and a release lever connected to the release lever. The adjustment link, which is rotatably supported and pressed by the cam of the adjustment dial, is connected to the tension spring engaged by the release lever, and when the line of action of the tension spring as the release lever rotates passes the dead center. In a thermal overload relay comprising a movable plate that reverses and a contact device that connects and separates by reversing the movable plate, the fulcrum of the adjustment link is set between the fixed side locking portion of the tension spring and the fulcrum of the movable plate. A thermal overcurrent relay, characterized in that it is disposed between the locking part and the fulcrum on a line connecting the two. 2) The thermal overcurrent relay according to claim 1, wherein the fulcrum of the adjustment link is disposed near the tension spring engagement point of the release lever. 3) In the thermal overload relay according to claims 1 and 2, a through hole or a protrusion is fixed on the adjustment link side, and a protrusion or a protrusion is provided on one side, respectively, and a rotation fulcrum is formed by combining them with each other. A thermal overload relay characterized by: