JP2979820B2 - Radiation sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation sensor used for a cooling / heating machine such as a fan heater and an air conditioner.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional radiation sensor is provided with a concave reflecting mirror 32 at an opening of a box-shaped case 31, and a sensor mounting plate 33 is arranged in front of the concave reflecting mirror 32. The thermistor 34 is fixed so as to be located at the focal point of the concave reflecting mirror of the mounting plate 33, and the concave reflecting mirror 3
2, the case frame 35 was attached to the box-shaped case 31 from the front.

The radiation sensor collects radiant heat entering through an opening 36 of a case frame 35 into a thermistor 34 by a concave reflecting mirror 32 and detects the amount of radiant heat.

[0004]

However, in the above-mentioned conventional configuration, since the concave reflecting mirror 32 is merely provided in the box-shaped case 31, this radiation sensor is used in a place where the heater becomes warm such as in the heater body. In this case, the heat is transmitted to the vicinity of the thermistor 34 through the wall of the box-shaped case 31 and the concave reflecting mirror 32, and the amount of radiated heat cannot be accurately detected, that is, the detection accuracy is deteriorated.

In order to solve this problem, it has been considered that a heat insulating material 37 is filled between the box-shaped case 31 and the concave reflecting mirror 32. However, when the material of the heat insulating material is varied, for example, when styrene foam is used, the foam density varies. In the case of wool, a new problem arises in that the heat insulation performance changes due to variations in the amount of wool and the like, and the detection accuracy varies depending on the object and the quality is not stable. Further, there is a problem that an extra member is required, assemblability is deteriorated, and cost is high.

The sensor mounting plate 33 is provided on the case frame 3.
5 is fixedly held by attaching it to the box-shaped case 31, but it is easy to move at that time, so that the assemblability is poor, and the thermistor 34 is connected to the concave reflecting mirror 32.
There is also a problem that the detection sensitivity is degraded by deviating from the focus. Further, since the sensor mounting plate 33 is only sandwiched between the box-shaped case 31 and the case frame 35, even if the thermistor 34 is accurately assembled at the focal point of the concave reflecting mirror 32, the sensor mounting plate 33 can be connected to the heater body. If a strong shock is received during the assembly or transport as a part, the position is shifted, and there is also a problem that reliability is lacking.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a high-quality radiation sensor having good detection accuracy or detection sensitivity.

[0008]

In order to achieve the above object, the present invention provides a case, a concave reflecting mirror covering an opening of the case, a sensor mounting plate provided on a front surface of the concave reflecting mirror, and The sensor mounting plate includes a thermistor disposed at the focal point of the concave reflecting mirror, and a case frame attached to the case so as to fix the concave reflecting mirror and the sensor mounting plate to the case, wherein the case has an outer wall portion. A heat insulating wall surrounding the outer periphery of the concave portion of the concave reflecting mirror is formed with a gap for heat insulation inside, and a concave portion for fitting a sensor mounting plate is provided at an opening edge of the case, and the case is provided with the concave portion. A locking claw or an engaging portion is formed on the frame, and the case claw or the engaging portion is fitted to the engaging portion or the locking claw provided on the case, thereby connecting the case frame to the opening edge of the case. I will fix it by pressing It is configured to.

[0009]

According to the radiation sensor of the present invention, even if the radiation sensor is provided in a warm place such as the inside of the heater body, the heat is blocked by the heat insulating wall and the space between the heat insulating wall and the case wall.
The vicinity of the thermistor is hardly affected by this heat. Also, the sensor mounting plate is less likely to move during assembly, and since the case frame is fixedly pressed to the case, it does not move after assembly.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2, reference numeral 1 denotes a box-shaped case.
It is made of a heat-resistant resin, and its front surface is opened. In this case 1, a heat insulating wall 4 is integrally formed so as to form a gap 3 with the case wall. A concave portion 5 is formed on a pair of opposing sides of the opening edge,
A pair of convexly protruding engaging portions 6 are formed on the outer surface of the case wall.

Reference numeral 7 denotes a concave reflecting mirror formed by making a central portion of a flat plate made of stainless steel or the like concave.
The case 1 is fitted to the opening of the case 1 so as to be located inside. Reference numeral 9 denotes a strip-shaped sensor mounting plate disposed on the front surface of the concave reflecting mirror 7, which is formed of a transparent thin resin plate. Both ends of the sensor mounting plate are fitted into the concave portion 5 at the edge of the case opening. Reference numeral 10 denotes a thermistor fixed to the concave reflecting mirror focal point of the sensor mounting plate 9 with an adhesive, and a lead wire 11 is drawn out of the case 1 along the back surface of the sensor mounting plate 9.

Reference numeral 12 denotes the sensor mounting plate 9 and the concave reflecting mirror 7
The sensor mounting plate 9 and the concave reflecting mirror 7 are fixed to the case 1 by being attached to the case 1 by attaching to the case 1 from a front surface of the case 1. That is, the case frame 12 is pressed into contact with the opening edge of the case 1 by fitting the claw portion 14 of the locking claw 13 integrally formed on the back surface of the case frame 12 into the engaging portion 6 of the case 1. It is composed. At this time, the hole 15 provided at the base of the locking claw 13 is fitted to the protrusion 16 of the engaging portion 6 protruding from the opening edge of the case 1 to prevent the position from shifting left and right. ing. Reference numeral 17 denotes an opening at a portion of the concave reflecting mirror 7 which faces the concave portion 8.

FIG. 3 shows a cross section when the radiation sensor having the above structure is attached to an oil fan heater. In the radiation sensor, a mounting piece 18 formed integrally with the case 1 is screwed to an operation base 20 of an apparatus main body 19 with screws 21. It is attached. 2
Reference numeral 2 denotes a perforated plate such as a punching plate provided at a portion facing the concave portion 8 of the concave reflecting mirror 7 of the radiation sensor. The perforated plate 2 is attached to the front plate 25 of the device main body 19 via the resin frame 23 and the packing 24. is there. In the drawing, reference numeral 26 denotes a heat source such as a burner, and 27 denotes an air outlet 28 mixed with hot air from this heat source.
A fan for supplying more warm air, 29 is a duct forming a path of the warm air.

In the above configuration, even if the ambient temperature of the case 1 is slightly increased due to, for example, radiant heat from hot air in the duct, the heat is doubled by the gap 3 and the heat insulating wall 4 in the case 1. Will be shut off. Therefore, the temperature near the thermistor 10 on the front surface of the concave reflecting mirror 7 hardly rises, and the thermistor 10 accurately detects a change in the amount of radiant heat from the outside collected by the concave portion 8 of the concave reflecting mirror 7 via the porous plate 22. Become.

A gap 3 in the case 1 for performing the above-mentioned heat shielding.
The heat insulating wall 4 can be made constant by design, so that its heat shielding effect does not vary depending on the object. Therefore, the detection of the amount of radiation heat by the thermistor 10 becomes stable. In addition, the heat insulating wall 4 comes into contact with the peripheral edge of the concave portion 8 of the concave reflecting mirror 7 for positioning, as well as heat shielding, and the concave reflecting mirror 7 is set at a predetermined position simply by being fitted into the case 1. Can do things.

On the other hand, the sensor mounting plate 9 of the radiation sensor is mounted on the case frame 12 after fitting both ends of the sensor mounting plate 9 into the concave portion 5 provided at the opening edge of the case 1, so that the sensor mounting plate 9 moves at that time. The thermistor 10 can be easily assembled, and the thermistor 10 is accurately held at the focal point of the concave reflecting mirror 7. Further, the case frame 12 is configured such that the claw portion 14 of the locking claw 13 is
Since the sensor mounting plate 9 is fixed to the opening edge of the case 1 by press-fitting, the sensor mounting plate 9 does not move out of the recess 5. Therefore, even if a strong shock is received at the time of assembling to the apparatus main body or transporting as a part, the position is maintained at the focal point as it is.

In the above embodiment, when the case frame 12 is mounted on the case 1, the locking claws 13 are provided on the case frame 12 side and the engaging portions are provided on the case 1 side. An engaging portion may be provided on the case 1 and a locking claw may be provided on the case 1 side, and the heat insulating wall 4 also serves to position the concave reflecting mirror 7, but this may be provided with separate positioning means. May be any configuration as long as the objects and effects of the present invention are achieved.

[0018]

As described above, the radiation sensor of the present invention can accurately detect the amount of radiant heat with a small influence even if it is provided in a warm place such as in the main body of the apparatus, and the detection variation. Can be reduced, and the detection accuracy becomes extremely high. Also, the quality of the sensor mounting plate can be greatly improved, for example, the position of the sensor mounting plate does not shift during assembly, and the sensor mounting plate does not move after assembly. In addition, the assemblability is improved, and a member for heat insulation is not separately required.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a radiation sensor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the radiation sensor.

FIG. 3 is a sectional view of an oil fan heater equipped with the radiation sensor.

FIG. 4 is a sectional view showing a conventional radiation sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 3 Gap 4 Heat insulation wall 5 Concave part 6 Engagement part 7 Concave reflector 9 Sensor mounting plate 10 Thermistor 12 Case frame 13 Locking claw

Continuation of the front page (56) References JP-A-2-166334 (JP, A) JP-A-4-348234 (JP, A) JP-A-64-86013 (JP, A) JP-A-1-75837 (JP) , U) (58) Fields surveyed (Int.Cl. ⁶ , DB name) G01K 7/22 G01K 1/20

Claims (2)

(57) [Claims] 1. A case, a concave reflecting mirror covering an opening of the case, a sensor mounting plate provided on a front surface of the concave reflecting mirror, and a focal point of the concave reflecting mirror of the sensor mounting plate. And a case frame attached to the case so as to fix the concave reflector and the sensor mounting plate to the case, wherein the case is provided with a gap for heat insulation inside an outer wall portion of the concave reflector. A radiation sensor having a heat insulating wall surrounding the outer periphery of the concave portion. 2. An opening edge of the case is provided with a concave portion into which a sensor mounting plate is fitted, and a locking claw or an engaging portion is formed in the case frame body. 2. The radiation sensor according to claim 1, wherein the case frame is press-fitted and fixed to an opening edge of the case by being fitted to an engaging portion or a locking claw provided.