JP2000283090A - Protecting device of axial fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early detect the temperature rise by abnormality of an axial fan and surely protect it by heat-exchangeably laying a temperature detecting element along a core part having a winding wound thereon, and interrupting the current-carrying to the axial fan when the temperature of the core part detected by the temperature detecting element reaches a prescribed upper limit value. SOLUTION: When an axial fan 2 is locked by clogging of dust in the rotation of the axial fan 2 by the operation of a refrigerator or the like, a lock current is carried to the winding of a core part 4 to raise the temperature. This temperature rise is detected by a thermal fuse heat-exchangeably laid along the core part 4, and when the detected value reaches an upper limit value, the thermal fuse 9 is opened to interrupt the current-carrying to the axial fan 2. According to this, the axial fan can be surely protected. The thermal fuse 9 is arranged within a through-hole 7 located in the center of a retaining plate 6 mounted on the diagonal of a frame 3 and brought into contact with the core part 4 in such a manner as to be heat exchangeable. According to this, the thermal fuse 9 can be stably retained to ensure the detection of the temperature of the core part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for an axial fan used as a cooling fan or a condensing fan for a showcase or a refrigerator.

[0002]

2. Description of the Related Art Conventionally, in an open showcase, for example, JP-A-6-82143 (F25D17)
/ 06), various blowers are used. In particular, a so-called axial fan composed of a shading motor in which a stator winding is provided at the center of the core and a short-circuit ring (shading coil) is provided at a position deviated from the center of the iron core is used for other induction motors. In comparison, loss due to heat generated by the shading coil is large, and when foreign matter enters the motor of the axial fan, rotation failure, stop, or lock of the axial fan is likely to occur.

[0003] Therefore, it is difficult to use in places where there is a lot of dust, places where outside air is introduced, places where it is difficult to see, and the like. Such a conventional axial fan 2 is shown in FIG. In this figure, 3 is a frame, 4 is a core portion on which a shading winding (not shown) is wound, 5 is a blade portion driven by the core portion, and 11 is a power cord. The core portion 4 is arranged at the center of the frame 3, and the blade portion 5 is located in the surrounding frame 3 and is driven to rotate by the core portion 4.

[0004] In order to prevent the axial fan 2 from inconveniences such as poor rotation, stoppage or locking due to heat generation, conventionally, an impedance protection method (core section of the axial fan 2) is used as a protection device. No. 4, a method of suppressing abnormal heat generation of the axial fan 2 by means of a winding resistance wound around the coil 4 is used.

[0005]

However, such a protection device as in the impedance protection system is based on the standard that it is sufficient that no abnormality such as ignition occurs after 72 hours from the locking of the axial fan 2. Because of the protection, the winding wound around the core portion 4 of the axial fan 2 often exceeds the limit temperature, and is incomplete as a protective device for use over a long period of six months and one year. Was.

An axial fan mounted on the ceiling surface of a showcase and used to form an air curtain at an opening is rarely inspected daily and is hardly found even if it is locked. For this reason, an abnormality may be noticed only when the axial fan is ignited.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art, and has as its object to provide a protection device capable of detecting and protecting a temperature rise due to an abnormality of an axial fan early and reliably. I do.

[0008]

That is, in the protection device for an axial fan according to the present invention, a core portion on which a winding is wound is provided at a center portion of a frame, and a blade portion rotatably driven by the core portion is provided. A temperature detecting element disposed in a frame outside the core portion, the temperature detecting element being attached to the core portion in an inductive manner, and the temperature of the core portion detected by the temperature detecting element is set to a predetermined upper limit. When the value reaches the value, the power supply to the axial fan is cut off.

[0010] In addition to the above, the axial fan protection device according to the second aspect of the present invention may further include a holding plate that is attached across an end of one surface of the frame and passes through a center portion of the one surface of the frame. And a through hole formed in a holding plate located at a central portion, wherein the temperature detecting element is disposed in the through hole and held by the holding plate, and is brought into contact with the core part by heat exchange.

[0010] Further, according to a third aspect of the present invention, in the axial fan protection device, the temperature detecting element is a thermal fuse in each of the above inventions.

Further, in the protection device for an axial fan according to a fourth aspect of the present invention, the temperature detecting element in the first or second aspect of the present invention is a bimetal thermostat.

[0012]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an axial fan 2 to which the present invention is applied.
FIG. In this figure, components denoted by the same reference numerals as those in FIG. 2 are the same.

The axial fan 2 of the embodiment is provided in an open showcase, a refrigerator, or the like (not shown). Reference numeral 3 denotes a frame. (Not shown), a core section 4 composed of a shaded motor is wound thereon, and is held at the tips (centers of the frame 3) of the bars 3A ... extending from the four corners of the frame 3 toward the center. I have.

Around the core 4, there are arranged blades 5, which are rotated and driven by the core 4, and housed in the frame 3. A holding plate 6 made of a vertically long substantially rectangular steel plate is mounted on a diagonal line from the upper right corner to the lower left corner of the frame 3 serving as a back surface of the core portion 4, and the holding plate 6 includes upper right and lower left bars 3A, It is provided substantially along 3A. Also,
At substantially the center of the holding plate 6, a through hole 7 (through hole) cut and raised so as to penetrate the holding plate 6 is provided.

The through hole 7 is formed to have a size in which a temperature detecting element to be described later can be inserted, and is provided on both sides in the longitudinal direction of the through hole 7 so as to be bent substantially perpendicularly to the holding plate 6 from the inside of the through hole 7. Height dimensions (dimensions slightly higher than temperature sensing elements)
Are formed.

Then, with the holding plate 6 attached diagonally to the frame 3, a through hole 7 is located substantially at the center of the holding plate 6, and this through hole 7 corresponds to the back surface of the core portion 4. Then, a temperature fuse 9 as a temperature detecting element is inserted into the through hole 7, and is fixed to the holding plate 6 with an adhesive tape 12 or the like.

The thermal fuse 9 is inserted between the cut-and-raised pieces 8 and 8 and is provided on the back surface of the core portion 4 by heat exchange. As a result, the temperature of the core portion 4 becomes
It is detected by.

A lead wire 10 is connected to the thermal fuse 9, and both ends of the lead wire 10 are connected to a power supply circuit (not shown) of the axial fan 2. Thermal fuse 9
When the temperature of the core portion 4 reaches a predetermined upper limit value (an upper limit temperature at which the axial fan 2 is not damaged, or an upper limit temperature at which it does not ignite due to heat generation), the power supply circuit of the axial fan 2 can be cut off. Connected to the circuit.

When the open showcase or the refrigerator is operated to rotate the axial fan 2 and the dust or the like is clogged and locked, a large lock current flows through the windings of the core portion 4. Rises.

Then, the thermal fuse 9 attached to the core portion 4 in an inductive manner detects this, and when the thermal fuse 9 reaches the upper limit, the thermal fuse 9 is opened to energize the axial fan 2. And the operation of the axial fan 2 is stopped.

As described above, the thermal fuse 9 is attached to the core portion 4 of the axial fan 2 in a heat-exchange manner.
When the detected temperature of the core portion 4 reaches a predetermined upper limit value, the energization to the axial fan 2 is cut off. However, it is possible to stop the operation before the winding of the core section 4 causes smoke or ignition due to the temperature rise.

In particular, the holding plate 6 is attached along the diagonal line between the ends of the back surface of the frame 3 so as to pass through the center of the frame 3 and to have a through hole in the holding plate 6 located at the center of the frame 3. 7 is formed, the thermal fuse 9 is disposed in the through hole 7 and is held by the holding plate 6, and the thermal fuse 9 is in contact with the core portion 4 in a heat-exchange manner. The temperature of the core portion 4 can be reliably detected, and the operation of the axial fan 2 itself is not hindered.

Further, since the holding plate 6 is arranged along the bars 3A, 3A, an increase in ventilation resistance is minimized.

Although the temperature fuse 9 is used in the embodiment, a bimetal thermometer (indicated by 9A) may be used as the temperature detecting element. In this case, when the temperature of the core section 4 reaches the upper limit, the circuit is opened to cut off the current supply, and when the abnormality is eliminated, the circuit can be closed again to start the operation.

[0025]

As described above in detail, according to the present invention, the core portion on which the winding is wound is provided at the center portion of the frame, and the blade portion driven by this core portion is rotated outside the core portion. In an axial fan arranged in a frame, a temperature detecting element is added to the core part in a heat-exchange manner, and when the temperature of the core part detected by the temperature detecting element reaches a predetermined upper limit value, the axial flow Since the power supply to the fan is cut off, the operation of the axial fan can be stopped based on a rise in the temperature of the core.

In this way, in the case where the axial fan is locked by foreign matter, for example, the abnormality is detected properly due to a rise in the temperature of the core, thereby avoiding the problem of smoke and ignition from the windings. It becomes possible.

According to the second aspect of the present invention, in addition to the above, the holding plate is attached between the ends of the one surface of the frame so as to pass through the center of the one surface of the frame and to be located at the center of the frame. A through hole is formed, and the temperature detecting element is arranged in the through hole and held by the holding plate, and is in contact with the core part by heat exchange, so that the temperature detecting element is stably held, and In addition, the temperature of the core can be reliably detected, and the operation of the axial fan is not hindered.

According to the third aspect of the present invention, since the temperature detecting element is constituted by a thermal fuse, when the temperature of the core portion reaches the upper limit, the circuit is cut by the thermal fuse, and the temperature fuse is reliably removed. The protection operation can be performed.

According to the fourth aspect of the present invention, since the temperature detecting element is formed of a bimetal thermo circuit, when the temperature of the core reaches the upper limit value, the circuit is opened to cut off the current and the abnormality is eliminated. In such a case, the circuit can be closed again to start the operation.

[Brief description of the drawings]

FIG. 1 is a rear view of an axial fan to which a protection device of the present invention is attached.

FIG. 2 is a back view of a conventional axial fan.

[Explanation of symbols]

 2 axial flow fan 3 frame 4 core part 5 blade part 6 holding plate 7 through hole 9 thermal fuse

Claims (4)

[Claims] 1. An axial flow system comprising: a core portion on which a winding is wound is provided at a center portion of a frame; and a blade portion rotationally driven by the core portion is disposed in the frame outside the core portion. The fan, further comprising: a temperature detection element provided in the core part so as to be indirectly attached thereto,
A protection device for an axial fan, wherein the energization to the axial fan is stopped when the temperature of the core portion detected by the temperature detecting element reaches a predetermined upper limit. 2. A holding plate attached across an end of one surface of a frame and passing through a center portion of the one surface of the frame, and a through hole formed in the holding plate located at the center portion, 2. The axial flow fan protection device according to claim 1, wherein a temperature detecting element is disposed in the through hole and held by the holding plate, and is brought into contact with the core portion in a heat-exchange manner. 3. The protection device for an axial fan according to claim 1, wherein the temperature detecting element is a thermal fuse. 4. The protection device for an axial fan according to claim 1, wherein the temperature detection element is a bimetal thermostat.