JP2012022974A - Thermal overload relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal overload relay capable of holding an adjusting dial at a fixed position, and obtaining stable action characteristics.SOLUTION: The thermal overload relay comprises a outer case 1, and an adjusting dial 12 inserted in an adjusting dial insertion hole 1a provided on the outer case 1 and adjusting a setting current. An engaging portion 12a provided on a peripheral surface of the adjusting dial 12 is pressed in a locking portion 1a of the adjusting dial insertion hole 1a provided on the outer case 1 to engage with each other. The adjusting dial 12 is composed of an upper surface portion 12b and a shaft portion 12c, and has a cam portion 12d at a lower end of the shaft portion 12c. On a peripheral surface of the shaft portion 12c, the engaging portion 12a to be pressed in the adjusting dial insertion hole 1a is provided. The adjusting dial insertion hole 1a is provided with a stepped portion 1e at a contact portion 1d of the adjusting dial insertion hole 1a so as to warp the upper surface portion 12b of the pressed-in adjusting dial 12, and a space is provided between the adjusting dial insertion hole 1a and the adjusting dial 12.

Description

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

First, FIG. 5 shows a typical conventional structure of the thermal overload relay described above.
In FIG. 5, 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 linked 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 linked to the releasing lever 4, and a slider 7 connected to the reversing spring 6. The output contacts 8 (a contact) and 9 (b contact) that open and close in response to the movement of the slider 7 and the reset switch 10 are assembled. 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 links the upper end side of the adjustment link 11 to adjust the settling current.

  The operation of the thermal overload relay is well known, and when the main bimetal 2 bends due to the overload current flowing in the main circuit, the release lever 4 rotates around the support shaft 11b via the shifter 3 and reverses. The 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 (for example, see Patent Document 1).

  Next, a method for adjusting the settling current value of the thermal overload relay will be described. In FIG. 5, when the adjustment dial 12 is turned, the adjustment link 11 in contact with the cam portion 12 c is displaced using the case support shaft 1 b of the outer case 1 as a fulcrum. Along with this, the release lever 4 connected to the adjustment link 11 is also displaced and moved, and the gap between the release lever 4 and the tip of the shifter 3 can be changed.

  Here, a method of assembling the adjustment dial 12 to the outer case 1 will be described with reference to FIG. In FIG. 6, in order to hold the adjustment dial 12 at a predetermined assembly position, the adjustment portion 12 a provided on the peripheral surface of the adjustment dial 12 is press-fitted into the adjustment dial insertion hole 1 a provided in the outer case 1. It is inserted into the dial insertion hole 1a. At that time, the height dimension b from the upper surface portion 12b of the adjustment dial 12 to the upper end of the engaging portion 12a provided on the peripheral surface of the adjustment dial is related to the adjustment dial 12 of the adjustment dial insertion hole 1a from the upper end of the outer case 1. It is set longer than the height dimension a up to the lower end of the locking portion 1c to be stopped.

JP 2001-160346 A

  By the way, in the above-described conventional thermal overload relay, when the adjustment dial 12 is press-fitted into the adjustment dial insertion hole 1a of the outer case 1, as shown in FIG. Further, rattling occurs also in the direction of (R), and the adjustment dial 12 is not held in a fixed position, resulting in variations in operating characteristics.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a thermal overload relay capable of holding an adjustment dial in a fixed position and obtaining stable operating characteristics.

In order to achieve the above object, according to the present invention, an outer case and an adjustment dial that is inserted into an adjustment dial insertion hole provided in the outer case and adjusts a settling current are provided on the peripheral surface of the adjustment dial. In the thermal overload relay in which the engagement portion provided is press-fitted into the engagement portion provided in the outer case and engaged, the adjustment dial includes an upper surface portion and a shaft portion, The lower end has a cam portion, and the peripheral surface of the shaft portion is provided with an engaging portion for press-fitting into the adjustment dial insertion hole, and the adjustment dial insertion hole is an upper surface portion of the press-fitted adjustment dial Therefore, the contact portion of the adjustment dial insertion hole is provided with a step, and a space is provided between the adjustment dial insertion hole and the adjustment dial. Further, the above-described thermal overload relay can be configured in a specific manner as described below.
(1) The height dimension from the upper surface of the adjustment dial to the upper end of the engagement portion provided on the peripheral surface of the adjustment dial is a locking portion where the adjustment dial of the adjustment dial insertion hole is locked from the upper end of the outer case. It is set to be shorter than the height dimension to the lower end of the above (claim 2).
(2) The lower end shape of the engaging portion provided on the peripheral surface of the adjustment dial is tapered.

According to the above configuration, by bending and holding the upper surface of the adjustment dial, the axial direction of the adjustment dial and horizontal play relative to the axial direction can be eliminated, and the number of parts can be increased. Instead, by holding the adjustment dial in a fixed position, it is possible to obtain stable operating characteristics.

Enlarged view of the adjustment dial of the present invention The perspective view of the thermal overload relay which shows the Example of this invention The expanded perspective view of the AA cross section shown in FIG. Enlarged view of part B shown in FIG. Front view of internal structure of thermal overload relay showing conventional example Enlarged view of conventional adjustment dial Enlarged view of part C shown in FIG.

Hereinafter, the form for implementing this invention is demonstrated based on the Example shown in FIGS.
FIG. 1 is an enlarged view showing an adjustment dial of a thermal overload relay of the present invention, FIG. 2 is a perspective view of the internal structure of the thermal overload relay showing an embodiment of the present invention, and FIG. FIG. 4 is an enlarged perspective view of a section B shown in FIG. 3.

  That is, in the embodiment shown in FIG. 1, an engagement portion 12 a made of a protrusion is provided on the peripheral surface of the shaft portion 12 c of the adjustment dial 12 so as to protrude from the peripheral surface, and the adjustment dial is inserted into the outer case 1. At the lower end of the hole 1a, there is provided a locking portion 1c for press-fitting and holding the engaging portion 12a provided on the peripheral surface of the shaft portion 12c of the adjustment dial.

As shown in FIG. 1, when the adjustment dial 12 is press-fitted into the adjustment dial insertion hole 1a of the outer case 1, the engagement portion 12a provided on the peripheral surface of the shaft portion 12c of the adjustment dial 12 is moved to the adjustment dial insertion hole 1a. The adjustment dial 12 can be retained from the adjustment dial insertion hole 1a by being held by the locking portion 1c. In addition, when the adjustment dial 12 is press-fitted into the locking portion 1c of the adjustment dial insertion hole 1a, the shape of the lower end side of the engagement portion 12a provided on the peripheral surface of the shaft portion 12c of the adjustment dial 12 so as to facilitate the press-fitting. Is tapered.
The upper surface portion 12b of the press-fitted adjustment dial 12 is in contact with the contact portion 1d of the outer case 1, and a step 1e is provided in the contact portion 1d of the adjustment dial insertion hole 1a of the outer case 1, as shown in FIG. Like F, the upper surface portion 12b of the adjustment dial 12 is held so as to be bent.
At this time, the height dimension b from the upper surface portion 12b of the adjustment dial 12 to the upper end of the engaging portion 12a provided on the peripheral surface of the shaft portion 12c of the adjustment dial 12 is from the upper end of the outer case 1 to the adjustment dial insertion hole 1a. By setting shorter than the height dimension a up to the lower end of the locking portion 1c to which the adjustment dial 12 is locked, the upper surface portion 12b of the adjustment dial 12 can be bent.
Further, when the deflection of the upper surface portion 12 b of the adjustment dial 12 is further increased, the groove portion 12 e may be provided in the shaft portion 12 c of the adjustment dial 12.
As a result, the engagement portion 12a provided on the peripheral surface of the shaft portion 12c of the adjustment dial 12 that is press-fitted and held and the upper surface portion 12b of the adjustment dial 12 are held in contact by the contact portion 1d of the outer case 1, thereby The backlash between the case 1 and the adjustment dial 12 is eliminated, and stable operating characteristics can be obtained.

DESCRIPTION OF SYMBOLS 1 Outer case 1a Adjustment dial insertion hole 1b Case spindle 1c Locking part 1d Contact part 1e Step 2 Main bimetal 3 Shifter 4 Release lever 4a Compensation bimetal 5 Contact opening / closing mechanism 6 Reversing spring 7 Slider 8, 9 Output contact 10 Reset switch 11 Adjustment link 12 Adjustment dial 12a Engagement portion 12b Upper surface portion 12c Shaft portion 12d Cam portion 12e Groove portion

Claims (3)

  An adjustment case provided in the outer case, and an adjustment dial that is inserted into an adjustment dial insertion hole provided in the outer case and adjusts a settling current, and an engagement portion provided in a peripheral surface of the adjustment dial is provided in the outer case In the thermal overload relay that is press-fitted into and engaged with the locking portion of the dial insertion hole, the adjustment dial includes an upper surface portion and a shaft portion, and has a cam portion at the lower end of the shaft portion. And an engagement portion for press-fitting into the adjustment dial insertion hole on the peripheral surface of the shaft portion, and the adjustment dial insertion hole is configured to flex the upper surface portion of the press-fitted adjustment dial. A thermal overload relay, characterized in that a step is provided at the contact portion of the insertion hole, and a space is provided between the adjustment dial insertion hole and the adjustment dial.   The thermal overload relay according to claim 1, wherein the height dimension from the upper surface of the adjustment dial to the upper end of the engagement portion provided on the peripheral surface of the adjustment dial is from the upper end of the outer case to the adjustment dial insertion hole. A thermal overload relay, characterized in that it is set shorter than the height dimension to the lower end of the locking portion where the adjustment dial is locked. 2. The thermal overload relay according to claim 1, wherein a lower end shape of an engaging portion provided on a peripheral surface of the adjustment dial is tapered.