JPH11230396A - Actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of dew condensation with efficient heating, and to reduce the energy loss by providing a heater at a part for transmitting the heat to an actuator so as to be cooled. SOLUTION: In an air conditioning ball valve 1 using an actuator, a PTC heater 18 is fitted in a case 9 at the air conditioning ball valve 1 side near an output shaft 10. With this structure, when the PTC heater 18 is electrified by a power source so as to generate the heat, the atmospheric temperature is heated to the predetermined temperature (40-50 deg.C) by a self-temperature- control mechanism. Furthermore, the heat generated by the PTC heater 18 is transmitted from a lower board 12 or the case 9 so as to heat the output shaft 10, and inside of the case 9 is warmed by the convection by the heat and the radiation heat of the PTC heater. Consequently, generation of dew condensation in the actuator 8 by the cold transmitted from the cooling fluid of the air conditioning ball valve 1 to the output shaft 10 is eliminated, and the generation of dew condensation can be efficiently prevented, and the energy loss is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator for driving a rotary driving device, and more particularly to an actuator for driving a rotary valve such as an air conditioning ball valve or a butterfly valve to prevent dew condensation. .

[0002]

2. Description of the Related Art For example, when a low-temperature fluid such as cooling or freezing is supplied to a pipe on which a rotary valve such as an air-conditioning ball valve is mounted, the temperature of the outer surface of the pipe or the rotary valve becomes dew point based on the temperature and humidity of the atmosphere. Condensation forms on these outer surfaces when: Therefore, usually, a heat insulating material is wound around the outside of the pipe or the rotary valve to prevent direct contact with the atmosphere, thereby preventing dew condensation on these parts.

[0003] In this type of rotary valve, an actuator is generally mounted on the upper part of the rotary valve so as to be perpendicular to the pipe. The outer circumference of the rotary valve having a long valve stem is provided with a heat insulating material. In general, the actuator mounted above the rotary valve is exposed to the outside of the heat insulating material.

In this case, the cold heat from the cold water passing through the rotary valve is transmitted through the stem of the rotary valve and the valve stem, reaches the flange, and is transmitted from the flange to the actuator. Dew condensation occurs from the output shaft of the actuator that is in contact with the outside air. When dew forms around the inside and outside of the actuator in this way, there are problems such as rust inside the actuator, electrical failure inside the actuator, or water droplets flowing and polluting the surroundings. Various measures have been proposed to prevent this.

As a countermeasure against this conventional problem, in the ball valve for air conditioning, as shown by a two-dot chain line in FIG. Some of them are heated to prevent electrical failure due to condensation in high temperature and high humidity environment. In addition, Japanese Patent Publication No. 8-6833 describes that a heater is provided in an electric case attached to an actuator so that the ambient temperature in the electric case is maintained at a predetermined temperature.

[0006]

However, according to the above-mentioned prior art, since the entire interior of the actuator is heated or the inside of the electrical case attached to the actuator is heated to prevent dew condensation, the capacity of the heater is large. Therefore, there is a problem that energy loss is extremely large. In addition, since this type of conventional heater always generates a constant amount of heat, it generates a constant amount of heat even when the outside air temperature rises and falls. In addition to the conventional heating method, the conventional heating element occupies a large space inside the actuator, which is against the downsizing of the actuator.

SUMMARY OF THE INVENTION The present invention has been developed in view of the conventional problems, and has as its object to provide a heater at a portion where heat is transferred to an actuator to be cooled, thereby forming dew by efficient heating. The use of a heater that does not heat over a certain temperature will not cause excessive temperature rise, is excellent in safety, and uses a heater that does not take up space. It is to provide a contributing actuator.

[0008]

In order to achieve the above object, the present invention transmits the rotation of a motor provided in a case to an output shaft via a gear train, and connects the output shaft to a driven member. In the actuator that is driven in combination, a heater is mounted near the output shaft near the driven member side in the case. In this case, the heater is a PTC (Positive Temp).
It is preferable to use an erasure heater.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an actuator according to the present invention is applied to a ball valve for air conditioning will be described below with reference to FIG.

The air-conditioning ball valve 1 shown in FIG. 1 is provided with a ball 4 having a through hole 3 in a body 2 rotatably through a stem 5, and the stem 5 is a long valve shaft cylinder provided on the body 2. 6 is mounted on the shaft. At the upper end of the valve stem 6,
A flange portion 7 having both ends protruding is integrally formed, and an actuator 8 is fixed to an upper surface of the flange portion 7 with a bolt (not shown).

The case 9 of the actuator 8 is formed by assembling a resin lower case 9a and a resin upper case 9b with bolts or the like. Further, the insertion flat surface 5a formed on the upper end of the stem 5 is connected to the output shaft 1 of the actuator 8.
0 is inserted into the forked portion 10a formed at the lower end of the output shaft 10
And the stem 5 are coupled so as to rotate integrally. The connecting means of the stem 5 and the output shaft 10 is not limited to this. Further, the output shaft 10 is provided with a protruding portion 10b by protruding the case 9 of the actuator 8 and uses the protruding portion 10b for manual operation or as an opening display function.

Further, an upper substrate 11 and a lower substrate 12 formed of a metal plate or a resin plate are attached to the case 9 by bolts or the like. The upper substrate 11 has a motor 14 for supplying power from a lead wire 13 and an output shaft. 10 are provided, and limit switches 16, 16 and the like, which are brought into contact with and separated from each other by the cams 15, 15, are provided.
To reciprocate and open and close automatically.

An output shaft 10 meshed with a gear 17a integral with the drive shaft 14a of the motor 14 and the intermediate gear group 17b, and meshed with the intermediate gear group 17b is provided between the upper substrate 11 and the lower substrate 12. And a reduction gear train 17 composed of an integral gear 17c.
12 is held by a support 19. This upper and lower substrate 1
1 and 12 also rotatably support the output shaft 10 described above.

A plate-shaped PCT heater 1 is provided near the output shaft 10 connected to the stem 5 of the ball valve 1.
The PCT heater 18 is provided on the lower substrate 12. The PCT heater 18 has a positive temperature coefficient, a resistance value increases rapidly at a specific temperature, has electrodes on both end faces, and is used as a constant-temperature heating element having a self-temperature control function. , And is most suitable for the actuator of the present invention. The PCT heater 18 is provided in the case 9
May be provided directly on the inner peripheral surface of the. In the above example, the PCT heater is used as the heater. However, even if another heater is used, it is possible to prevent the output shaft from being cooled by the transfer of cold heat from the stem, and the object of the present invention can be achieved.

The PCT heater 18 is a plate-shaped ceramic element sealed in a resin case, has little change over time, is free from fire or the like, is safe, and does not take up space. Therefore, it is suitable for an actuator such as a ball valve for air conditioning in the present invention. Further, although the PTC heater 18 is energized and generates heat when the power supply 21 is turned on, the PTC heater 18 may be switched by an appropriate switch means to generate heat when necessary. In the figure, reference numeral 20 denotes a ball seat of the ball valve 1, reference numeral 21 denotes a power source,
2 is an operation switch.

FIG. 2 is a circuit diagram showing an example of FIG. 1. This circuit configuration includes a power supply 21, a motor 14 having a capacitor 24, a PCT heater 18 connected to a power supply circuit, and a motor 51. 1 connected to the output shaft 10
The open-side limit switch (OLS) 16 and the close-side limit switch (SLS) 16 alternately connected to the open-side NO and the close-side NC by the switches 5 and 15, respectively, and connected to these limit switches 16 and 16 to open the valve. Alternatively, it is constituted by a valve-opening lamp 23a and a valve-closing lamp 23b which electrically indicate the valve-closing state.

Next, the operation of the above embodiment will be described. Since the PTC heater 18 is mounted near the output shaft 10 near the air conditioning ball valve 1 side in the case 9, the PT
When the C heater 18 is energized and the PCT heater 18 generates heat, its ambient temperature is heated to a predetermined temperature (40 to 50 ° C.) by the self-temperature control function.

The heat generated by the PTC heater 18 is generated by the lower substrate 12.
Alternatively, the heat is transferred from the case 9 to heat the output shaft 10 and also to heat the inside of the case 9 by convection and radiant heat due to the heat of the PTC heater 18. The dew condensation can be efficiently prevented without dew condensation on the actuator 8 due to the cold transmitted to the output shaft 10.

[0019]

As is apparent from the above, according to the present invention, the heater is mounted near the output shaft near the driven member side in the case, so that the cooled output shaft is efficiently heated. Therefore, energy loss is small, and the occurrence of dew condensation on the actuator can be reliably prevented.

Further, by using the PTC heater, the heating is not performed at a certain temperature or more even when the outside air temperature rises or falls, the heating energy is small, and since the heating is not performed at a certain temperature or more, the temperature rises excessively. Since there is no risk of fire or the like, the safety is excellent, and the actuator can be provided which does not take up space for the actuator and contributes to downsizing.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which an actuator according to the present invention is applied to an air conditioning ball valve.

FIG. 2 is a circuit diagram of FIG.

[Explanation of symbols]

 Reference Signs List 1 driven member (ball valve for air conditioning) 8 actuator 9 case 10 output shaft

Claims (2)

[Claims] 1. An actuator for transmitting rotation of a motor provided in a case to an output shaft via a gear train, and connecting the output shaft to a driven member to drive the output shaft. An actuator, wherein a heater is mounted near a near output shaft. 2. The actuator according to claim 1, wherein the heater is a PTC heater.