JP4304454B2 - Thermal overload relay - Google Patents

Description

  The present invention relates to a thermal overload relay (thermal relay) used in combination with an electromagnetic contactor and the like, and more particularly to an assembly structure of an adjustment dial mechanism.

First, the conventional structure of the thermal overload relay described above will be described with reference to FIGS. In FIG. 4, 1 is an outer case made of a resin mold, 2 is a main bimetal that is bent by the heat generated by the heater 2a connected to the main circuit, 3 is a shifter connected to the free end of the main bimetal 2, and 4 is a shifter 3 The release lever 5 is driven by the release lever 4 and is an opening / closing mechanism for the output contact. The opening / closing mechanism 5 includes a reversing spring 6 connected to the releasing lever 4 and a slider 7 connected to the reversing spring 6. The assembly includes an output contact 8 (a contact) and 9 (b contact) that open and close in response to the movement of the slider 7 and a reset bar 10. Reference numeral 11 denotes an adjustment link that pivotally holds the release lever 4 so that it can swing. Reference numeral 12 denotes an adjustment dial that is connected to the upper end side of the adjustment link 11 to adjust the settling current.
Here, the adjustment link 11 is a structure as shown in FIGS. 5 (a) and 5 (b), and a bearing portion 11a formed at the center thereof is pivotally supported by a support shaft 1a provided on the outer case 1, The release lever 4 is pivotally supported by a link pin 11b provided on the lower end side. Further, a fine adjustment cam 11c is provided at the upper end of the adjustment link, and the cam 11c is brought into contact with the peripheral surface of a cam portion (eccentric cam) 12a provided at the lower portion of the adjustment dial 12. A leaf spring 13 having both wings bent in a V shape is caulked and secured to the back surface of the intermediate portion of the link 11 (slightly higher than the position of the bearing hole). The cam 11c provided at the upper end of the adjustment link 11 is pressed against the cam surface of the adjustment dial 12 by the spring reaction force. Further, in order to hold the adjustment dial 12 at a predetermined installation position, a spring wire (for example, a piano wire) is provided between the peripheral surface of the adjustment dial 12 and the outer case 1 as shown in FIG. The spring member 14 bent into a shape is interposed in a bent state, and the adjustment dial 12 is pressed and held at a fixed position by the spring reaction force.

The detailed structure and function of the plate spring 13 that presses the adjustment link 11 against the cam portion of the adjustment dial 12 is described in Patent Document 1, and the spring member 14 that holds the adjustment dial 12 in a fixed position is disclosed in Patent Document 1. 2 is disclosed.
The operation of the thermal overload relay is well known. When the main bimetal 2 bends due to the overload current flowing in the main circuit, the release lever 4 rotates about the support shaft 11b through the shifter 3 to turn the reversing spring. 6 is reversed, the slider 7 of the opening / closing mechanism 5 is driven, the output contacts 8 and 9 are reversed, and a contact signal is output.
Japanese Utility Model Publication No. 4-2441 Japanese Utility Model Publication No. 53-95168 (FIGS. 4 and 5)

By the way, in the above-described thermal overload relay of the conventional configuration, two separate parts, a leaf spring 13 and a spring member 14, are prepared in order to hold the adjustment link 11 and the adjustment dial 12 in place. Therefore, there is a problem that the number of parts and assembly man-hours in product assembly increase.
The present invention has been made in view of the above points, and has improved the assembly structure of the adjustment dial mechanism so that the number of parts and assembly man-hours for holding the adjustment dial and the adjustment link in place can be reduced with the aim of reducing costs. An object of the present invention is to provide a thermal overload relay.

In order to achieve the above object, according to the present invention, a main bimetal that is bent by energization of an overcurrent, a shifter that is displaced in response to the bending of the main bimetal, and a release lever that is driven by the displacement of the shifter are provided in the outer case. An output contact opening / closing mechanism driven by a release lever, an adjustment link that pivotally supports the release lever, and an adjustment dial with a cam that adjusts the settling current connected to one end of the adjustment link are installed internally. In a thermal overload relay that opens and closes the output contact by capturing the bimetal curve, a hook-like spring member is interposed between the outer case and the peripheral surface of the adjustment dial to hold the adjustment dial in place. A leg portion is provided, and the leg portion is engaged with the back surface of the adjustment link , and the tip end portion is pressed and urged against the cam portion peripheral surface of the adjustment dial (Claim 1). in front A dial holding part that bends the spring member into a U shape and is press-fitted between the outer case and the peripheral surface of the adjustment dial, and a hook shape that extends from the front end of the holding part and engages the back surface of the adjustment link It is comprised by the bending process goods of the spring wire which formed the leg part (Claim 2).

  According to the above configuration, an assembly part that has been divided into two independent parts and assembled to the adjustment dial mechanism can be handled with one simple wire spring part, thereby reducing the number of parts and the number of assembly steps. Reduction can be achieved.

Hereinafter, specific modes for carrying out the invention will be described based on the embodiments shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the same member corresponding to FIGS. 4-6, and the description is abbreviate | omitted. That is, in the illustrated embodiment, a hook-like leg portion is provided on a spring member 14 interposed between the outer case 1 and the peripheral surface of the adjustment dial 12 to press and hold the adjustment dial in a fixed position. Is engaged with the back surface of the adjustment link, and the fine adjustment cam 11c provided on the upper end side of the adjustment link is pressed against the cam surface of the adjustment dial 12 by the spring force of the leg portion.
Specifically, as shown in FIGS. 2 (a) and 2 (b), a spring wire (for example, a piano wire) is bent into a U shape so that the space between the inner wall surface of the outer case 1 and the peripheral surface of the adjustment dial 12 is increased. The dial holding part 14a that is press-fitted in a bent state extends downward from the dial holding part 14a and is engaged with the back surface of the adjustment link 11, and the spring force of the cam 11c of the adjustment link 11 causes the peripheral surface of the cam part 12a of the adjustment dial 12 The spring member 14 is formed by forming an L-shaped hook-shaped leg portion 14b formed so as to be pressed and urged to the spring. In this embodiment, the leaf spring 13 attached to the back surface of the adjustment link 11 in the conventional structure of FIG. 4 is omitted.

  In the assembly process of the thermal overload relay, the dial holding portion 14a of the spring member 14 made of a wire spring is press-fitted between the inner wall surface of the outer case 1 and the adjustment dial 12, The part 14 b is engaged with the back surface of the adjustment link 11. Accordingly, the recess 14a-1 of the spring member 14 presses the adjustment dial 12 in the direction of arrow B to hold the dial in a predetermined position, and at the same time, the leg portion 14b of the spring member 14 presses the adjustment link 11 in the direction of arrow C. Then, the cam 11 c provided at the upper end of the adjustment link 11 can be pressed against the cam portion 12 a of the adjustment dial 12.

FIG. 2 is an assembly structure diagram of an adjustment dial mechanism according to an embodiment of the present invention, where (a) and (b) are a front view and a side view, respectively. It is a figure showing the shape of the spring member in FIG. 1, (a), (b) is a side view and a plan view respectively Overall configuration diagram of a thermal overload relay employing the assembly structure of FIG. Overall configuration diagram of conventional thermal overload relay corresponding to FIG. FIG. 5 is an assembly structure diagram of the adjustment dial mechanism in FIG. 4, (a) and (b) are a front view and a side view, respectively. It is a figure showing the shape of the spring member holding an adjustment dial using the assembly structure of FIG. 5, (a), (b) is a side view and a plan view, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer case 2 Main bimetal 3 Shifter 4 Release lever 5 Output contact opening / closing mechanism 11 Adjustment link 12 Adjustment dial 12a Cam part 14 Spring member 14a Dial holding part 14b Leg part

Claims (2)

A main bimetal that is bent by energization of an overcurrent, a shifter that is displaced in response to the bending of the main bimetal, a release lever that is driven by the displacement of the shifter, an output contact opening / closing mechanism that is driven by the release lever, An adjustable link that supports the release lever and an adjustment dial with a cam that adjusts the settling current connected to one end of the adjustment link are installed in the interior. In the overload relay, a hook-like leg is provided on the spring member that is interposed between the outer case and the peripheral surface of the adjustment dial to hold the adjustment dial in place, and the leg is attached to the back of the adjustment link . A thermal overload relay, characterized in that it engages and presses and urges its front end portion against the cam portion peripheral surface of the adjustment dial. 2. The thermal overload relay according to claim 1, wherein the spring member is a bent product of a spring wire, and is bent into a U shape and is press-fitted between the outer case and the peripheral surface of the adjustment dial. And a hook-shaped leg portion that extends from the tip of the holding portion and engages with the rear surface of the adjustment link.

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