JP2003106917A - Bourdon tube pressure gauge - Google Patents

Abstract

(57) [Summary] [Problem] To attach a pointer to a pointer shaft in a state where no pressure is applied and the pointer is aligned with a zero scale, and to plastically deform a plastic bending arm portion of a displacement enlarging mechanism under a maximum pressure pressurization state to maximize the pointer. Even after returning to a non-pressure state after matching the scale, the Bourdon tube pressure gauge can provide a Bourdon tube pressure gauge that can greatly improve the efficiency of the calibration and calibration work without drastically changing the pointer from the zero scale. SOLUTION: In the Bourdon tube pressure gauge, a displacement enlarging link mechanism includes a protruding piece 12, an arcuate connecting link 23, and a rotating plate 25 attached to a tube tip 1b. The V-shaped arm piece 26 is used as an adjuster in the state where the maximum pressure is applied to the rotating plate 25, and in the non-pressure state, the bendable node P is the first rotation between the projecting piece 12 and the bow-shaped connecting link 23. The position overlaps with the pair part 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Bourdon tube pressure gauge, and more particularly, to an improvement of a controller for calibrating calibration in a displacement magnifying mechanism for magnifying the tip displacement of a Bourdon tube and transmitting it to a pointer shaft. .

[0002]

2. Description of the Related Art The schematic construction of a Bourdon tube pressure gauge that mechanically magnifies and displays the elastic strain of metal caused by a measurement pressure is as follows.
As shown in FIG. 3, a flat columnar gauge main body 2 in which a Bourdon tube 1 having an elliptical cross section is bent and housed, for example, in an annular shape,
The pressure introducing pipe 3 has a male screw portion 5b screwed into a mounting hole (screw hole) 5 having a female screw portion 5b on the measured side, which is connected to a pressure source to be measured through a communication hole 5a. 3a communicates with the tube base 1a of the Bourdon tube 1. A packing 6 is press-fitted into the bottom of the mounting hole 5. In addition,
7 is a mounting nut.

In the Bourdon tube pressure gauge, the radius of curvature of the Bourdon tube 1 gradually increases due to elastic deformation as the pressure increases, and the tube tip 1b gradually changes counterclockwise and outward in FIG. 3, but it is a slight displacement. Therefore, this displacement is mechanically magnified through a displacement magnifying mechanism, and the scale 4 of the dial 2a is designated to be magnified by the pointer 4 attached to the pointer shaft 4a.

FIG. 4 is a rear view showing a displacement magnifying link mechanism of a conventional Bourdon tube pressure gauge. This displacement magnifying mechanism
As the pressure increases, the tip 1b is fixed around the pointer shaft 4a in the clockwise direction (arrow A) in FIG.
A straight connecting rod (connecting link) 13 formed by connecting a Bourdon tube 1 that gradually changes to the above and a projecting piece 12 that is fixed to a tube tip 1b via a first pin connection (rotating pair part) 12a.
And a second pin coupling 13 on the tip side of the connecting rod 13.
A pinion 11 pivotally attached to a pointer shaft 11 is rotatable (swingable) around a rotation center 15a with respect to a front frame plate 14 that is connected via a and is fixed to the pressure introducing pipe 3.
Rotating plate (sector) 1 with toothless gear 15b that meshes with
5 and. The rotary plate 15 has a curved arm piece (adjuster) 16 protruding outward, and is connected to the connecting rod 13 by a second pin coupling 13a on the tip side thereof.

When the pipe tip 1b is displaced in the direction of arrow A as the pressure increases, the connecting rod 13 rotates the curved arm piece 16 in the clockwise direction (direction of arrow B) about the center of rotation 15a, so that the pointer shaft 4a. Rotates counterclockwise (direction of arrow C) in FIG. The rotating plate 15 functions as a lever that swings, and the distance from the center of rotation 15a to the pointer shaft 4a (the length of the arm) is longer than the distance from the center of rotation 15a to the second pin coupling 13a (the length of the arm). S) is longer, the displacement amount of the pipe tip 1b is first expanded as the arc length of the pitch circle of the tooth-chipped gear 15b by the ratio of the length of the arm, and then the tooth-chipped gear 15b and the pinion are With the speed increasing ratio of 11, the rotation angle of the pointer shaft 4a is enlarged.

In a Bourdon tube pressure gauge having such a displacement magnifying mechanism, since there are variations in parts precision, assembly precision, etc., after the displacement magnifying mechanism is assembled,
Need to calibrate the pointer display. In the unpressurized state,
After attaching the pointer 4 to the pointer shaft 4a so that the pointer 4 points to zero, the maximum pressure is applied to read the pointer scale moved. When the pointer scale is less than the maximum pressure value, it means that the displacement magnification rate is low. Therefore, in order to shorten the distance from the rotation center 15a to the second pin coupling 13a, a plastic deformation that pushes the second pin coupling 13a toward the rotation center 15a side by sandwiching the curved arm piece 16 with a tool or the like is performed. Perform the adjustment and adjust so that the pointer scale matches the maximum pressure value. On the other hand, when the pointer scale exceeds the maximum pressure value, it means that the displacement magnification rate is high. Therefore, the center of rotation 15
In order to extend the distance from a to the second pin coupling 13a, a tool or the like is inserted into the notch 16a of the curved arm piece 16 and pushed and widened, and the second pin coupling 13a is further separated from the rotation center 15a Plastic deformation And adjust so that the pointer scale matches the maximum pressure value.

[0007]

However, the above-mentioned pointer alignment calibration work of the displacement magnifying mechanism has the following problems.

That is, if the pressure-free state is restored after the plastic deformation adjustment for the curved arm piece 16 under the maximum pressure state, the inconvenience that the pointer 4 deviates from the zero scale occurs. When the second pin connection 13a is released, when viewed from the curved arm piece 16 side, the plastic deformation locus of the position of the second pin connection 13a draws a substantially arc α around the flexible node P as well. , When viewed from the connecting rod 13 side, the second pin coupling 13
The locus of the position of a draws an arc β around the first pin coupling 12a, and the arcs α and β are the second pin coupling 13a.
However, since the curved arm piece 16 and the connecting rod 13 are connected by the second pin coupling 13a, the pipe tip 1b is naturally elastic even when a slight force is applied. Since it deforms, when the position of the second pin coupling 13a is forcibly displaced on the circular arc α by the bending adjustment of the plastic deformation with respect to the curved arm piece 16, the first pin coupling 12a.
This is because the position of is also deviated, so that an unexpected initial stress is generated in the Bourdon tube 1.

Therefore, when the pointer scale is less than the maximum pressure value, the second pin coupling 1 is used to increase the displacement magnification rate.
In the plastic deformation adjustment in which 3a is brought closer to the rotation center 15a side, since the pipe tip 1b is pushed out to the arrow A, when the pressureless state is restored, the pointer 4 indicates the zero scale or more. For this reason, it is necessary to re-attach the pointer 4 and then pressurize it to the maximum pressure again to perform the maximum scale adjustment, which requires a troublesome work which is repeated many times until the zero scale and the maximum scale match. Skilled skills are required to distribute the adjustment of the pointer and the adjustment of plastic deformation.

On the contrary, when the pointer scale exceeds the maximum pressure value, in the plastic deformation adjustment in which the second pin coupling 13a is further separated from the rotation center 15a in order to reduce the displacement enlargement ratio, the pipe tip 1b is not in the arrow A direction. Since it will be pulled down in the opposite direction, the pointer 4 points below the zero scale when returning to a non-pressurized state. In such a case as well, it takes a lot of trouble to repeat the process until the zero scale and the maximum scale match.

In view of the above problems, an object of the present invention is to mount the pointer on the pointer shaft in a state where the pointer is aligned with the zero scale in a pressureless state, and plastically deform the bending arm portion under the maximum pressure applied. After adjusting the pointer to the maximum scale, even if it is returned to the unpressurized state, the pointer does not greatly deviate from the zero scale, and the displacement magnifying mechanism is improved to point to approximately the zero scale. (EN) Provided is a Bourdon tube pressure gauge capable of greatly improving the efficiency of calibration work for calibration without requiring.

[0012]

In order to solve the above problems, in a Bourdon tube pressure gauge according to the present invention, the tube tip is gradually moved around the pointer shaft in the first direction with respect to the fixed node as the pressure increases. The changing Bourdon tube, the connecting link that is connected to the tip side of the pipe via the first turning pair, and the second linking portion that is connected to the tip side of the connecting link via the second turning pair. And a rotating body for rotating a pointer shaft, the rotating body having a second turning pair portion at a tip side thereof, and the second rotating pair of the bending nodes. Has a bending arm whose expansion angle can be adjusted to be expanded and contracted with respect to the rotating pair of the rotating body and the rotation center, and the connecting link and the bending arm move the rotating body in the first direction as the pressure increases. It has a mutual relationship of rotating. Since the pressure can be converted into the gas temperature, this Bourdon tube pressure gauge can be used as, for example, a remote thermometer by replacing the dial with a temperature display.

The bending arm portion according to the present invention includes
It is characterized in that the bendable node is formed so as to substantially overlap with the first turning pair in the non-pressure state. That is, unlike the conventional example, the bendable node is located on the first turning pair side with respect to the line passing through the second turning pair and the center of rotation, and in the non-pressurized state, A line segment connecting the second turning pair part and the flexible node substantially overlaps a line segment connecting the second turning pair part and the first turning pair part of the connecting link. For this reason, when the connection of the second pair of rotation parts is released, the trajectory of the position of the second pair of rotation parts of the connecting link substantially overlaps the plastic deformation track of the position of the second pair of rotation parts of the bending arm. Therefore, the bending arm is plastically deformed under the maximum pressure printing pressure to adjust the distance between the second rotating pair and the center of rotation, and after adjusting the pointer to the maximum scale, return to the non-pressure state. However, the pointer does not go far from the zero scale.
Therefore, the calibration work efficiency can be significantly improved as compared with the conventional case. For example, it is possible to complete a large number of calibrations by setting a large number of Bourdon tube pressure gauges at the same time, printing the maximum pressure at the same time, plastically deforming each bent arm portion and sequentially adjusting the maximum scales. It is possible to eliminate the trouble of re-adjusting by printing the maximum pressure of the second time and thereafter, and it is possible to shorten the adjusting work without requiring a skilled person.

The bending arm portion is a bifurcated bending piece having a proximal end side portion projecting from the center of rotation to the flexible node and an outer side portion projecting outward from the center of the flexible node. Therefore, it is desirable that a notch for tooling is formed on the inner side where both pieces face each other. By forming the notch for tooling, for example, the tip of a flat-blade screwdriver can be engaged with the notch and plastically deformed easily, so that the adjusting workability is speeded up and unintentional deformation failure can be prevented.

It is desirable that the position of the tool-contacting cut on the base end side piece and the position of the tool-contacting cut on the outer side piece are formed at unequal distances from the bendable node. For example, the tip of a flat-blade screwdriver is held in both notches and twisted in one direction to increase the opening angle, and twisting in the opposite direction reduces the opening angle, so that the adjustment work can be surely and quickly realized.

Further, it is desirable that the connecting link has an arched shape located outside the outer piece with respect to the center of rotation. Since the connecting link is not straight but has an arcuate shape, there is a gap between the connecting link and the outer piece b, which facilitates adjustment of plastic deformation.
Therefore, the bow-shaped connecting link has a meaning as an adjuster for correcting the deviation between the bendable node and the first rotating pair in the pressureless state. Further, when adjusting the plastic deformation of the bending arm portion, it is difficult for the tip of the tool to hit the connecting link, so that it is possible to prevent unintentional deformation.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a rear view showing a displacement magnifying link mechanism in a pressureless state in a Bourdon tube pressure gauge according to an embodiment of the present invention, and FIG. 2 is a maximum pressure printing state in a Bourdon tube pressure gauge according to an embodiment of the present invention. FIG. 6 is a rear view showing the displacement enlarging link mechanism of FIG. In addition, in FIGS.
The same parts as those shown in FIG. 4 are designated by the reference numerals, and the description thereof will be omitted.

The displacement magnifying link mechanism of this embodiment gradually changes in the clockwise direction (arrow A) in FIG. 1 with respect to the pressure introducing pipe 3 in which the pipe tip 1b is a fixed node around the pointer shaft 4a as the pressure increases. A bow-shaped connecting link 23 formed by connecting the Bourdon tube 1 and a projecting piece 12 fixed to the tube tip 1b via a first pin connection (rotating pair part) 12a, and a tip end side of the connecting link 23. It is rotatable (swingable) about a rotation center 25a with respect to a front frame plate 14 and a back frame plate 24 that are connected to each other via a second pin coupling 23a and are fixed to the pressure introducing pipe 3. Rotating plate (pitch arm, sector) 25 having a toothless gear 25b that meshes with a pinion 11 mounted on a pointer shaft 4a
It has and. If the displacement of the pipe tip 1 is assumed to be a virtual long link, the displacement magnifying link mechanism includes a fixed node (the pressure introducing pipe 3, the front side frame plate 14 and the back frame plate 24), the Bourdon pipe 1, the protrusions 12, It can be regarded as a bi-lever mechanism of a four-bar rotary chain consisting of the bow-shaped connecting link 23 and the rotary plate 25.

The rotary plate 25 has a V-shaped arm piece ((regulator at maximum pressure) 26 having an opening angle θ that can be expanded and contracted and projects outward.
Is connected to the connecting link 23 by a second pin coupling 23a on the tip side thereof. In addition, 27 is a balance spring for preventing the pointer movement due to a meshing gap (backlash) between the pinion 11 and the toothless gear 25b.

The V-shaped arm piece 26 is a bifurcated bent piece that is bent at a bendable node P at an acute angle, and is bent along with the base end side piece 26a that extends from the rotation center 25a side to the bendable node P. The outer side piece 26b extends outward from the node P and has a notch 26c between the base side piece 26a and the outer side piece 26b to form an opening angle θ. Minus driver contact cuts X and Y are formed on the inner sides of the two pieces 26a and 26b facing each other. The distance from the flexible node P to the notch X position is shorter than the distance from the flexible node P to the notch Y position, and the notch X and Y are one side, and the flexible node P is one side.
Triangles including vertices as vertices are formed to be isosceles triangles.

The V-shaped arm piece 26 is capable of expanding and contracting the opening angle θ by plastic deformation with the bendable node P as a bending point. In the pressureless state of FIG. 1, the bendable node P has the first turning pair portion 12
It is in a position that substantially overlaps a. That is, the bendable node P is different from the conventional example shown in FIG. 4 with respect to the line passing through the second rotation pair part 23a and the rotation center 25a.
The line segment connecting the second turning pair portion 23a of the V-shaped arm piece 26 and the bendable node P is located on the 2a side and is in a non-pressurized state. It substantially overlaps with the line segment connecting the one-turn pair part 12a.

In the calibrating work of the pointer, in the non-pressure state, first, as shown in FIG. 1, it is confirmed whether or not the bendable node P overlaps the first turning pair portion 12a. When they overlap, but are slightly off, the protrusion 1
2 and the bow-shaped connecting link 23 are bent and adjusted. Since the connecting link 23 is not straight but has an arcuate shape, there is a gap between the connecting link 23 and the outer piece 26b, which facilitates adjustment of plastic deformation. Therefore, the bow-shaped connecting link 23 has a meaning as a regulator (second regulator) in a pressureless state. Then, the pointer 4 is attached to the pointer shaft 4a so that the pointer 4 points to zero.

Next, when the maximum pressure is applied, the pipe tip 1b
Is largely displaced in the direction of arrow A, the rotating plate rotates in the direction of arrow B, and the pointer shaft 4a rotates in the direction of arrow C.
The state shown in FIG. 2 is obtained. Here, read the pointer scale that has been moved. When the pointer scale is less than the maximum pressure value, it means that the displacement magnification rate is low. Therefore, the center of rotation 2
In order to shorten the distance from 5a to the second pin coupling 23a, a minus driver is engaged with the notches X and Y and twisted counterclockwise in FIG. 2 to bring the second pin coupling 23a closer to the rotation center 25a side. Perform plastic deformation according to the guidelines and adjust so that the pointer scale matches the maximum pressure value. At this time, since the scale can be adjusted only by adjusting the twist of the minus driver, the adjustment work becomes simple. On the other hand, when the pointer scale exceeds the maximum pressure value, it means that the displacement magnification rate is high. Therefore, in order to extend the distance from the rotation center 25a to the second pin coupling 23a, a minus driver is engaged with the notches X and Y and twisted clockwise in FIG. 2, so that the second pin coupling 23a is rotated. Perform plastic deformation further away from and adjust so that the pointer scale matches the maximum pressure value. Also in this case, the adjustment work can be simplified because the scale can be adjusted only by adjusting the twist of the minus driver.

After that, when the pressure is returned to the non-pressure state, the pointer 4 remains on the zero scale. This is because the bendable node P overlaps the first turning pair portion 12a in the pressureless state. That is, when the connection of the second turning pair portion 23a is released, the second turning pair portion 23a of the V-shaped arm piece 26 is added to the locus of the position of the second turning pair portion 23a of the connecting link 23.
Since the plastic deformation loci at the position of are exactly overlapped with each other, the V-shaped arm piece 26 is plastically deformed in the state of maximum pressure impression to adjust the distance between the second rotating pair part 23a and the rotation center 25a, and the pointer 4 After adjusting to the maximum scale, even if the pressure is returned to the non-pressurized state, the pointer does not greatly deviate from the zero scale. Therefore, the calibration work efficiency can be significantly improved as compared with the conventional case. For example, a large number of calibrations can be completed by setting a large number of Bourdon tube pressure gauges at the same time, printing the maximum pressure at the same time, plastically deforming each V-shaped arm piece 26, and aligning the V-shaped arm pieces 26 to the maximum scale in order. It is possible to eliminate the trouble of re-adjusting by applying the maximum pressure for the second time and thereafter, and it is possible to shorten the adjustment work without requiring an expert.

The shape of the V-shaped arm piece 26 as the adjuster at the maximum pressure is not limited to the V-shape, but may be another shape such as a U-shape. However, the position of the U-shaped bendable node P shown in FIG. 4 is somewhat ambiguous, but the V-shaped arm piece 26 is clear because the bendable node P is an acute-angled vertex.
It is excellent in that it is possible to obtain the overlay accuracy with the first turning pair portion 12a.

Further, the second expanding mechanism is not limited to the toothless gear 25b and the pinion 11, but a coil spring wound around the pointer shaft 4a and a rotary plate 25 having a peripheral edge portion press-fitted into the coil gap. The second enlarging mechanism can be configured also by and.

[0027]

As described above, according to the present invention, the bendable arm which is the adjuster at the maximum pressure in the displacement magnifying mechanism of the Bourdon tube pressure gauge has the first bendable node when no pressure is applied.
Since it is characterized in that it is formed so as to be substantially overlapped with the pair of parts around, the following effects can be obtained. In other words, in the no-pressure state, the pointer is attached to the zero scale while it is attached to the pointer shaft, and after the maximum pressure is applied, the bending arm is plastically deformed so that the pointer matches the maximum scale. Even if it is returned, the pointer will not be significantly deviated from the zero scale, and will remain approximately at the zero scale. For this reason, it is possible to greatly improve the efficiency of the calibrating calibration work without requiring skilled skill.

[Brief description of drawings]

FIG. 1 is a rear view showing a displacement magnifying link mechanism in a pressureless state in a Bourdon tube pressure gauge according to an embodiment of the present invention.

FIG. 2 is a rear view showing the displacement magnifying link mechanism in the maximum pressure printing state in the Bourdon tube pressure gauge according to the embodiment of the present invention.

FIG. 3 is a front view showing a Bourdon tube pressure gauge.

FIG. 4 is a rear view showing a displacement magnifying link mechanism of a conventional Bourdon tube pressure gauge.

[Explanation of symbols]

1 ... Bourdon tube 1a ... tube base 1b ... Pipe tip 2 ... Gauge body 2a ... dial 3 ... Pressure introducing pipe 3a ... Pressure introducing hole 4 ... pointer 4a ... pointer shaft 5 ... Mounting hole (screw hole) 5a ... communication hole 5b ... Female screw part 6 ... packing 7 ... Mounting nut 11 ... Pinion 12 ... Protrusion 12a ... 1st pin coupling (rotating pair part) 14 ... Front side frame plate 23 ... Bow-shaped connecting link 23a ... Second pin coupling 24 ... Back frame plate 25a ... Center of rotation 25 ... Rotating plate (pitch arm, sector) 25b ... missing gear 26 ... V-shaped arm (regulator at maximum pressure) 26a ... Base end side part 26b ... One piece outside 26c ... Notch 27 ... Hairspring θ ... Opening angle P ... Flexible node X, Y ... Slot for a flat-blade screwdriver

Claims (4)

[Claims] 1. A Bourdon tube whose pipe tip gradually changes in a first direction with respect to a fixed node around a pointer shaft with an increase in pressure, and is connected to the pipe tip side through a first turning pair part. Connected to the tip end side of the connecting link via a second rotating pair part, which is rotatable around the center of rotation with respect to the fixed node and for rotating the pointer shaft. A rotating body, wherein the rotating body has the second rotating pair on the tip side, and the opening angle between the second rotating pair of the bendable node and the rotation center is expanded or contracted. A Bourdon tube pressure gauge having an adjustable bending arm, and the connecting link and the bending arm have a mutual relationship of rotating the rotating body in a first direction with an increase in pressure. In the unfolded state, the bendable arm has the bendable node as the first turning pair. Bourdon tube pressure gauge, characterized in that it is formed as in I overlap position. 2. The bending arm portion according to claim 1, wherein the bending arm portion includes a proximal end side portion protruding from the rotation center side to the flexible node and an outer side portion protruding outward from the flexible node. A Bourdon tube pressure gauge, comprising a bifurcated bent piece having a pair of tooling notches formed on the inner sides of the two pieces facing each other. 3. The position according to claim 2, wherein the position of the tool contacting cut of the base end side piece and the position of the tool contacting cut of the outer side piece are formed at unequal distances from the flexible node. Bourdon tube pressure gauge. 4. The Bourdon tube pressure gauge according to claim 2 or 3, wherein the connecting link has an arc shape located outside the outer piece with respect to the center of rotation.