JPH0544760Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention is a microbarometer used to detect the degree of clogging of the air filter of an air conditioner. This relates to a microbarometer that detects the difference in air pressure between a first chamber on the upper side and a second chamber on the lower side, which are partitioned by a diaphragm, by converting the rotational movement into rotational movement.

[Prior Art] A conventional microbarometer has a first band 2 whose one end is fixed to a diaphragm 1, as shown in FIG.
is wound around the rotating drum 3, and a second band 4, one end of which is fixed to the shaft 9 of the pointer 8, is wound around the rotating drum 3 in the same direction as the band 2. On the other hand, the shaft 5 of the rotating drum 3 is connected to one adjustment fitting 7 via a spiral spring 6, and the shaft 9 of the pointer 8 is connected to the other adjustment fitting 7 through another spiral spring 10. It is connected to the adjustment fitting 11. (Refer to Utility Model Publication No. 41-21835).

In the above configuration, when the air pressure in the lower second chamber 13 partitioned by the diaphragm 1 becomes lower than that of the upper first chamber 12, the band 2 becomes tense due to the downward displacement of the diaphragm 1, and the rotating drum 3 rotates in the direction shown by arrow C against the elastic force of spring 6, and thereby the pointer 8 is angularly displaced in the direction shown by arrow B.
The amount of angular displacement of the pointer 8 at this time is proportional to the amount of vertical displacement of the diaphragm 1, and the pressure difference between the first chamber 12 and the second chamber 13 is detected from the pressure value scale indicated by the pointer 8. I can do it.

[Problems to be solved by the invention] However, in the conventional microbarometer described above, the two bands 2 and 4 are pulled in the same direction by the spring 6 attached to the rotating drum 3. As the strength increases, the hysteresis increases, which has the disadvantage of lowering the precision of the instrument.
Furthermore, if the pressure difference becomes abnormally high, the downward force of the diaphragm 1 will apply excessive tensile force to the bands 2 and 4, which may cause the spring 6 to break or the bands 2 and 4 to break. It has the disadvantage that it cannot respond to changes in the maximum scale of pressure values.

Furthermore, as a transmission mechanism that transmits the movement of a disc that is displaced in accordance with the pressure difference between the first and second chambers to the pointer, a mechanism configured by a combination of a link mechanism and a crank mechanism has been known ( Jitsukai Showa 53-
(See Publication No. 41983).

However, according to the above configuration, since the link mechanism and crank mechanism are pin-coupled, the frictional resistance of the coupling part is high, and the movement of the disc cannot be minutely transmitted to the pointer, making it difficult to use as a microbarometer. Measurement accuracy tends to be relatively poor.

This invention was made in order to solve the above-mentioned conventional problems, and the purpose is to provide a microbarometer that is highly accurate and can also respond to changes in the maximum scale of pressure values.

[Means for Solving the Problems] The microbarometer according to this invention has a spring that rotates the pointer in a first direction attached to the shaft portion of the pointer, and a spring that rotates the pointer in a first direction. Wrap the band around the rotating drum. On the other hand, the rotating drum is connected to the diaphragm via a connecting member, and the vertical displacement of the diaphragm is converted into the rotational movement of a pointer, so that the upper first chamber and the lower chamber separated by the diaphragm are separated by the indicated position of the pointer. It detects the pressure difference with the second chamber of
The connecting member includes a plate-shaped elastic member and a second band. The elastic member has one lengthwise end fixed to the case, and the center part connected to the diaphragm via a hanging rod so as to be vertically displaceable. The second band has one end fixed to the tip of the elastic member and the other end wrapped around the rotating drum to apply a rotational force to the pointer in a second direction opposite to the first direction. It is added.

[Operation] According to this invention, the second
The band causes the pointer to move in a second direction opposite to the first direction.
Since the rotational force is applied in the direction of , there is no need to attach a conventional spring to the rotating drum. In addition, by appropriately setting the strength of the elastic member according to the magnitude of the pressure difference, the first
And excessive tensile force is prevented from being applied to the second band.

[Example] Hereinafter, an example of this invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of this invention. In the figure, parts corresponding to those of the conventional example shown in FIG.

Inside the barometer case 20 (see FIG. 2), a pointer 8, a rotating drum 3, and a diaphragm 1 are arranged in this order from top to bottom.

A spiral spring 10 applies a rotational force to the pointer 8 in the first direction indicated by the arrow A, and one end of the first band 2 is attached to the shaft 9 in the direction indicated by the arrow A. It is wrapped around and soldered.

The rotating drum 3 has a shaft portion 5 rotatably supported by a bearing portion (not shown). The other end of the band 2 is wound around the large diameter portion 3a of the rotating drum 3 in the direction indicated by arrow C and soldered.

On the other hand, the diaphragm 1 is connected to the rotating drum 3 via an elastic member 15 and a second band 4 that constitute a connecting member.

The elastic member 15 is, for example, a rectangular leaf spring having a predetermined thickness (elastic force), and as shown in FIG.
It is fixed to a frame 21 fixed at 0 with fixing screws 22 and adjusting screws 23. The tip of the adjustment screw 23 is in contact with a stopper portion 24 provided below the frame 21, and by turning the adjustment screw 23, one end 15a of the elastic member 15 is vertically displaced together with the frame 21. There is.
Thereby, the zero point of the pointer 8 can be slightly adjusted by adjusting the vertical position of the tip 15b of the elastic member 15.

Near the center of the elastic member 15 shown in FIG.
An insertion hole 16 is formed, and the upper end of a hanging rod 17 fixed to the diaphragm 1 is inserted through the insertion hole 16. A long hole 18 extending in the vertical direction in FIG. 2 is formed in the hanging rod 17.
A pin 19 fixed to the elastic member 15 by soldering or the like passes through the. Pin 19 is
When the diaphragm 1 is at a position corresponding to the zero point of the pointer 8, it is located at the upper end of the elongated hole 18, and when the diaphragm 1 is pushed up, it descends along the elongated hole 18 and the elastic member 15 Also, an excessive load is not applied to the bands 2 and 4.

The distal end portion 15b of the elastic member 15 is bent into a U-shape in a direction opposite to the diaphragm 1 (upward in FIG. 2) at a position above the small diameter portion 3b of the rotary drum 3, and band 4
One end 4a of is soldered. The other end portion 4b of the band 4 hangs downward and is wound around the small diameter portion 3b of the rotating drum 3 in the direction shown by arrow D, that is, in the opposite direction to the wrapping direction C of the first band 2. It is soldered with.
Thereby, the tensile forces by the bands 2 and 4 are applied to the rotating drum 3 in opposite directions.

In the above configuration, the first chamber 12 shown in FIG.
When the pressure difference between and the second chamber 13 increases,
The diaphragm 1 is displaced downward and the tip 15 of the elastic member 15
b is elastically deformed downward. At this time, band 4
is loosened, the rotating drum 3 is pulled by the band 2 and rotates in the direction of arrow D, and the pointer 8 is angularly displaced in the direction of arrow B by an amount corresponding to the amount of deformation of the elastic member 15 due to the elastic force of the spring 10. do. Further, if the diaphragm 1 descends too far and the pointer 8 swings out, the bands 2 and 4 become loose, and therefore, breakage of the bands 2 and 4 can be reliably prevented.

On the other hand, when the pressure difference decreases, the diaphragm 1 is upwardly displaced and the elastic member 15 is elastically deformed upward. At this time, the rotating drum 3 rotates in the direction of arrow C due to the tensile force of the band 4, and the pointer 8 returns in the direction of arrow A against the elastic force of the spring 10. Here, since the two bands 2 and 4 apply rotational force in opposite directions C and D to the rotating drum 3, the rotational force in the direction of arrow C is applied to the rotating drum 3 as in the conventional case. There is no need to separately provide a spring 6 (see FIG. 4) for this purpose. Therefore, the accuracy of the meter can be improved by eliminating the hysteresis caused by the spring 6. Furthermore, by reducing the number of springs 6 by one, the configuration of the rotating drum 3 is simplified.
Production costs can also be reduced.

Furthermore, since the long hole 18 is provided in the hanging rod 17 connected to the elastic member 15, it is possible to prevent an excessive load from being applied to the elastic member 15 and the bands 2 and 4 when the diaphragm 1 rises too much. This prevents the bands 2 and 4 from being cut.

Furthermore, by appropriately setting the plate thickness (elastic force) of the elastic member 15 according to the maximum scale of the pressure value,
It is possible to prevent an excessive load from being applied to the bands 2 and 4 even in a high pressure difference, and it is possible to correspond to changes in the maximum scale of pressure values. Moreover, since the elastic member 15 itself has no hysteresis, increasing the strength of the elastic member 15 can greatly contribute to improving the accuracy of the instrument.

In addition, in this embodiment, the center portion and tip portion 15b of the elastic member 15 are deformed in the same direction (downward side in FIG. 2) by the hanging rod 17 and the band 4, so that the elastic member 15 is straight It is possible to obtain similar deformation characteristics and improve measurement accuracy.

Furthermore, since the tip end 15b of the elastic member 15 is bent upward, soldering between the band 4 and the elastic member 15 is facilitated, and workability is improved. Moreover, since the soldering work can be carried out while adjusting the length of the band 4, the yield can be improved.

According to the inventor's experiments, the accuracy of the conventional microbarometer is F・S (full scale) [0 to 5 mmH ₂ O]
It has been confirmed that the accuracy of the microbarometer according to this invention can be kept within ±1.5% with respect to F·S, whereas the accuracy of the range meter is within ±5%.

As another embodiment of this invention, as shown in FIG. 3, the second band 4 is wound around the rotating drum 3 in the direction shown by arrow C, and the first band 2 is wound around the rotating drum 3 in the direction of arrow D. , the shaft portion 9 of the pointer 8 may be arranged at the same height as the lower part of the rotating drum 3.

[Effects of the invention] As explained above, according to this invention, there is no need to attach a spring to the rotating drum, so the hysteresis caused by the spring can be reduced and the accuracy of the instrument can be improved. In addition, by appropriately setting the strength of the elastic member,
It is possible to prevent excessive tensile force from being applied to the first and second bands, thereby making it possible to respond to changes in the maximum scale of pressure values.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of this invention, Fig. 2 is a vertical sectional view taken along the - line in Fig. 1, and Fig. 3 is a longitudinal sectional view taken along the line -
This figure is a schematic configuration diagram showing another embodiment of this invention, and FIG. 4 is a perspective view showing a conventional microbarometer. DESCRIPTION OF SYMBOLS 1... Diaphragm, 2... First band, 3... Rotating drum, 3a... Large diameter part, 3b... Small diameter part, 4...
...Second band, 8... Pointer, 9... Shaft, 10
... Spring, 12 ... 1st chamber, 13 ... 2nd chamber
Chamber, 15...Elastic member, A...First direction, B...
...Second direction, 17...Hanging rod, 20...Case.

Claims (1)

[Claims for Utility Model Registration] (1) A spring attached to the shaft of a pointer to rotate the pointer in a first direction, a rotating drum having a large diameter portion and a small diameter portion, and one end attached to the shaft. a first band to which is fixed and the other end wrapped around and fixed to the large diameter part of the rotating drum; a plate-shaped elastic member whose one end is fixed to the case and supported in a cantilever manner; a second band having one end fixed to the tip and the other end wrapped around and fixed to the small diameter portion of the rotating drum to apply a rotational force to the pointer in a second direction opposite to the first direction; , an elastically displaceable diaphragm that partitions a first chamber and a second chamber, and a hanging rod having one end movably suspended from the center of the elastic member and the other end fixed to the diaphragm. A microbarometer characterized in that the displacement of the diaphragm is converted into rotational movement of the pointer to detect the difference in air pressure between the first chamber and the second chamber. (2) The pointer, rotating drum, and diaphragm are arranged in this order from top to bottom inside the case.
The microbarometer according to claim 1, wherein the tip of the elastic member is bent upward, and one end of the second band is fixed to the bent portion. (3) The microbarometer according to claim 1 or 2, wherein a tensile force directed in the same direction is applied to the elastic member by the second band and the diaphragm.