JPH019068Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a Bourdon tube type switch, and more specifically, in a Bourdon tube type switch that generates an electrical signal based on the displacement of the free end of the Bourdon tube, the displacement of the free end of the Bourdon tube is This invention relates to an improvement in a mechanism for transmitting information to a switch section that performs target contact and separation.

A Bourdon tube type switch detects the state of the fluid to be measured in the Bourdon tube, such as a change in pressure, by operating the switch part by displacement of the free end of the Bourdon tube. Since the free end was in direct contact with the contact of the switch part, it had the following drawbacks.

That is, although a highly sensitive microswitch is usually employed as the switch section, the switch section including the microswitch has so-called hysteresis between the operating pressures when on and off. In other words, the load when pushing the contact of the switch section to make electrical contact and the load when releasing the contact to make electrical disconnection are different from each other. Therefore, there is an error, a so-called deadband difference, between the displacement position of the contact when it is on and the displacement position of the contact when it is off. The deadband difference of this switch part is usually at least about 0.05 mm, while the displacement of the free end of the Bourdon tube is usually about 1.2 mm.
When it is necessary to operate a Bourdon tube switch with high precision, the operating error based on the dead band difference has become so large that it cannot be ignored.

In addition, in a structure in which the free end of the Bourdon tube is in direct contact with the switch part, when the free end is excessively displaced,
During so-called overtravel, unreasonable force is applied to each part, potentially damaging the switch part, so conventionally the entire switch part was supported with leaf springs, etc.
When overtravel occurs, the entire switch section is displaced to prevent damage, but this has the disadvantage of requiring a large-scale configuration.

The purpose of this invention is to eliminate or reduce the operating error due to the dead band difference of the switch section, thereby enabling high-precision operation, and also to prevent the switch section from overtravelling when the free end of the Bourdon tube is excessively displaced (overtravel). The purpose of the present invention is to provide a safe bourdon tube type switch in which there is no risk of damage to the parts including the bourdon tube. In this case, the Bourdon tube type switch includes not only a pressure switch but also a temperature switch.

Therefore, the present invention provides a rotating lever that can transmit the displacement of one end to the other end according to the distance from the center of rotation, and that the one end can come into contact with the free end of the Bourdon tube. Providing a biasing means for rotating the lever in a direction in which it comes into contact with the free end side,
A switch portion that can come into contact with the other end of the rotary lever when the rotary lever rotates in a direction in which it comes into contact with the free end, and can be separated from the other end when the free end is excessively displaced. It was established. In other words, one end of the rotary lever follows the displacement of the free end of the Bourdon tube, the amount of movement is amplified as appropriate, and transmitted to the other end. The structure utilizes only the urging force of the urging means, so that the force acting on the contacts of the switch part can be adjusted by selecting the urging means. It is corrected and applied to the contact to eliminate or reduce the deadband difference of the switch section. Further, the switch portion is arranged so that when the rotary lever is rotated in the direction in which the rotary lever comes into contact with the free end side, the rotary lever comes into contact with the other end side of the rotary lever, that is, the rotary lever contacts the switch portion and the Bourdon tube. By adopting a structure in which the free ends are in contact with each other from the same direction of rotation, even if the free end is displaced excessively, the free end simply separates from the rotation lever, and a force greater than the biasing force of the biasing means is applied to the switch portion. The purpose is to achieve the above objective by preventing the addition of

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the overall structure of an embodiment of a Bourdon tube switch according to the present invention. In the figure,
The base 1 is formed into an oblong plate shape with a predetermined thickness, and a cover 2 having an approximately inverted bowl shape and having an oval cross-sectional shape like the base 1 is covered with a rubber ring 3. It is configured to be

As shown in FIG. 2, on the upper surface of the base 1, a fixed end boss 4 is integrally erected on the short axis of the ellipse and near the edge of the base 1. A C-shaped Bourdon tube 5 is installed on one side of the service boss 4.
The fixed end side of is fixed. The free end of the Bourdon tube 5 is arranged on the short axis of the ellipse and in a symmetrical position with the fixed end boss 4. In other words, the C-shaped Bourdon tube 5 has a C-shaped opening connected to the base 1. The base 1 is eccentrically arranged toward one longitudinal side (the left side in FIGS. 1 and 2) of the base 1 and the other longitudinal side (the right side in FIGS. 1 and 2) of the base 1.

Further, on the upper surface of the base 1, a cover attachment boss 6 having the same height as the fixed end boss 4 is integrally erected at a position surrounded by the Bourdon tube 5.
A screw hole 7 is formed in the upper end surface of each of the cover mounting boss 6 and the fixed end boss 4, and screws 8 are inserted into these screw holes 7 through the cover 2, so that the cover 2 is screwed into the screw hole 7. It is configured to be fixed to the base 1.

A plate support boss 11 is formed at the base end of the fixed end boss 4. This plate support boss 11 is arranged in the longitudinal direction (long axis direction) of the base 1.
It extends in the opposite direction to the side where the Bourdon tube 5 is provided (the left side in FIGS. 1 and 2).

Further, a plate fixing boss 12 having the same height as the plate supporting boss 11 is erected at the base end of the cover attaching boss 6, and this plate fixing boss 12 and the plate supporting boss 11 A substantially rectangular plate 13 is supported on top of the plate. That is, these bosses 1
A plate 13 placed on the tubes 1 and 12 is arranged so as to extend from the inside of the Bourdon tube 5 to one side in the longitudinal direction of the base 1 from the C-shaped opening.

One end side of the plate 13 (right end side in Figures 1 and 2)
A rotation center hole 14 is bored in the hole 14, and the plate 13 is fixed to the plate with the rotation center hole 14 as the rotation center by a screw 15 that passes through the rotation center hole 14 and is screwed into the boss 12. The plate 13 is rotatably mounted on the boss 12, and a long hole 16 is bored at the other end of the plate 13 (the left end in the figure).
A screw 17 passes through this elongated hole 16 and is screwed into the upper end surface of the tip of the plate support boss 11.
This allows the plate 13 to rotate within the range allowed by the elongated hole 16.
It is configured to be mounted on 1.

Further, the plate supporting boss 11 has a protrusion 1.
9 is formed, and an adjustment screw 18 that moves forward and backward in the direction of rotation of the plate 13 and whose tip abuts one side edge of the plate 13 is screwed into this protrusion 19 . After adjusting the position by moving the adjustment screw 18 back and forth, the plate 13 is brought into contact with the plate 13, and in this state, the plate 13 is moved between the bosses 11 and 1 by the screws 15 and 17.
By fixing the plate 13 on the plate 2, the mounting position of the plate 13 can be adjusted. Note that the adjustment screw 18 will be removed after adjusting the mounting position of the plate 13.

A micro switch 21 serving as a switch portion is screwed and fixed on the longitudinal rotation center side of the plate 13 (on the right side in the figure), in other words, on the inside of the Bourdon tube 5. Also, near the other end (toward the left) of the plate 13 is a support shaft 22 as a rotation shaft.
is erected, and a rotary lever 24 is rotatably fitted onto the support shaft 22 via a sleeve 23 serving as a bearing. At this time, the mounting position of the rotary lever 24 on the support shaft 22 is provided so as to be biased toward one end, so that displacement at one end is magnified and transmitted to the other end. The sleeve 23 is attached to the support shaft 2
It is prevented from coming off by an E-ring 22A fitted to the tip of 2.

Further, as shown in an enlarged view in FIG. A lubricant such as grease 2 is placed between the
6 is included.

On the other end side of the rotating lever 24 (right end side in the figure),
The metal material constituting the rotating lever 24 is the rotating lever 2
4 is crushed and plastically deformed into a plane perpendicular to the rotational direction of the contact portion 24A, and the contact portion 24A is formed.
At A, the rotating lever 24 is configured to be able to come into contact with the contact 27 of the micro switch 21 by rotating counterclockwise.

A plurality of spring mounting holes 28 are bored approximately in the longitudinally intermediate portion of the rotary lever 24, and a coil spring 31 as a biasing means is inserted into any one of the plurality of spring mounting holes 28. One end is attached. The other end of the coil spring 31 is attached to a spring mounting pin 32 erected at a predetermined position on the plate 13, and the biasing force of the coil spring 31 causes the rotation lever 24 to rotate about the support shaft 22. It is biased to rotate counterclockwise in FIGS. 1 and 2, and one end (left end in the diagram) of the rotation lever 24 is connected to a displacer (tube tip) 33 welded and fixed to the free end of the Bourdon tube 5. The rotary lever 24 is configured to rotate in accordance with the movement of the free end of the Bourdon tube 5. Therefore, even if the free end of the Bourdon tube 5 is excessively displaced outward, the rotating lever 2
The counterclockwise rotation of 4 is locked by the contact 27 of the micro switch 21, so that one end of the rotary lever 24 and the Bourdon tube 5 are separated from each other.
Further, if the free end is excessively displaced inward and the rotation lever 24 is excessively rotated clockwise,
The contact portion 24A on the other end side is spaced apart from the contactor 27.

Further, on the back surface of the base 1, as shown in FIG. 4, an installation protrusion 41 formed in the shape of a relatively thick metal plate is integrally provided and protrudes substantially perpendicularly to the back surface. An installation screw (not shown) is inserted into the screw insertion recess 42 of the installation protrusion 41 so that the Bourdon tube switch can be installed and fixed at a predetermined location.

Further, a fluid to be measured inlet 43 is formed at a position corresponding to the lower end of the fixed end boss 4 of the base 1 . This introduction port 43 is communicated with the fixed end opening of the Bourdon tube 5 in the fixed end boss 4, and the fluid to be measured supplied from the introduction port 43 is supplied into the Bourdon tube 5. ing. Further, a waterproof bushing 44 made of a rubber block or the like is attached near the inlet 43, and a lead wire 45 inserted through the waterproof bushing 44 is connected to a clip 47 (with a screw 46) on the upper end surface of the base 1. (see FIG. 2), the plate supporting boss 11 is fixedly supported on one side of the plate supporting boss 11.
One end of the lead wire 45 is introduced into the upper side of the base 1 and electrically connected to the microswitch 21, and a connector (not shown) is attached to the other end.

Next, the operation of this embodiment will be explained.

When the pressure of the fluid to be measured introduced into the Bourdon tube 5 from the fluid to be measured inlet 43 rises, the flat cross section of the Bourdon tube approaches a perfect circle, and the free end becomes approximately straight by a distance proportional to the pressure increase. Displaced to.
The displacement direction of the free end when the internal pressure increases is outward, that is, the direction in which the overall shape of the C-shaped Bourdon tube 5 tends to become straight, and as the free end is displaced, the displacement direction is directed outward. Contacting rotating lever 2
4 is rotated counterclockwise in FIG. 2 by the biasing force of the coil spring 31. Since the rotating lever 24 follows the displacer 33 by the coil spring 31, when the free end reaches a predetermined displacement position, the rotating lever 24
The contact portion 24A contacts the contact 27 of the microswitch 21, and the contact 27 is activated to generate an electrical signal within the microswitch 21.
This electrical signal is transmitted through lead wire 45 to an external mechanism.

If the pressure inside the Bourdon tube 5 further increases and the free end of the Bourdon tube 5 is displaced outward excessively,
The displacer 33 of the Bourdon tube 5 is only separated from one end of the rotating lever 24, and the micro switch 21
The contactor 27 is not affected by the excessive displacement of the displacer 33, and only the biasing force based on the coil spring 31 is applied.

Further, when the pressure inside the Bourdon tube 5 decreases and the free end of the Bourdon tube 5 is displaced in the opposite direction, the rotating lever 24 rotates clockwise in FIG. 2 against the biasing force of the coil spring 31. Therefore, the contact part 2
The pressure on the contactor 27 by 4A is released. That is, the microswitch 21 is shifted from the on state to the off state, and an electrical signal accompanying this shift is transmitted to the outside via the lead wire 45.

After this, when the pressure inside the Bourdon tube 5 further decreases and the free end of the Bourdon tube 5 is displaced inward excessively, the rotation lever 24 is further rotated clockwise, but in this case, the contact 24A is separated from the contactor 27 of the microswitch 21, thereby preventing the influence of excessive displacement.

Adjustment of the dead-cut difference is performed by selectively employing coil springs 31 having various biasing forces, or more simply by changing the position of the spring attachment hole 28. In this way, while applying a predetermined load from the coil spring 31 to the free end of the Bourdon tube 5 by the biasing force of the coil spring 31, the displacement of the free end is transmitted to the contact 27, so that the contact 27 is moved from the Bourdon tube 5 to the contact 27. By adjusting the load applied to the blade, the dead band difference can be eliminated or reduced.

Furthermore, the pressure at which the micro switch 21 is set to operate depends on the contact portion 24A and the contact 27 of the micro switch 21.
This is done by adjusting the distance between the This interval can be easily adjusted by adjusting the mounting position of the plate 13. That is, as shown in FIG.
After adjusting the rotation of the plate 13 around the screw 15 by extending it to the third side, the plate 13 may be fixed to both the bosses 11 and 12.

By adjusting the rotation of the plate 13 in this way, one end of the rotation lever 24 is always urged by the coil spring 31 and comes into contact with the displacement element 33, and the displacement element 33 is in a stopped state when not measuring. Because there is
When the support shaft 22 is moved as the plate 13 rotates, the distance between the contact portion 24A and the contactor 27 is adjusted by displacement (see the chain line in FIG. 5).

This embodiment has the following effects.

Since the load from the free end of the Bourdon tube 5 is not applied directly to the contact 27, but is applied to the contact 27 while the force relationship is corrected by the biasing force of the coil spring 31, various coil springs 31 are selected. By adopting this method, it is possible to eliminate or reduce the deadband difference that the micro switch 21 inherently has. Furthermore, since a plurality of spring mounting holes 28 are provided, the optimum load can be easily adjusted by changing the spring mounting position without replacing the coil spring 31 itself. Therefore, from these points of view, it is possible to provide a Bourdon tube switch that operates with high precision.

Further, in the embodiment described above, the rotation center (support shaft 22) of the rotation lever 24 is arranged at a position separated from the longitudinal center portion of the rotation lever 24 by a predetermined length on the opposite side from the contact portion 24A. , the displacement of the free end of the Bourdon tube 5 is caused by the rotation lever 24 at the contact portion 24A.
It has a structure that expands according to the distance from the center of rotation.

Therefore, even if the movement of the free end is slow and small, the movement of the contact portion 24A is rapid and large, and the contact 27 of the micro switch 21 can be actuated instantaneously. High precision operation can be performed. Moreover, if the contacts inside the micro switch 21 are connected or disconnected slowly, sparks will be generated between the contacts, and this spark will have the adverse effect of causing welding and wear of the contacts. but,
Activating the contactor 27 quickly (at high speed) has the effect of preventing such adverse effects. Furthermore, welding and abrasion between contacts can shift the position of the contacts and lead to lower accuracy in operating conditions, but preventing welding and abrasion between contacts also improves operating accuracy. be.

Also, the mounting position of the plate 13 is determined by the adjusting screw 18.
This has the advantage that the setting of the pressure value at which the micro switch 21 is activated when a pressure of any magnitude is applied to the Bourdon tube 5 can be changed and adjusted very easily.

In addition, since a recess 25 in which the lubricant 26 is sealed is formed on the circumferential surface of the support shaft 22, a sufficient amount (a large amount) of the lubricant 26 can be held in the gap between the support shaft 22 and the sleeve 23. Therefore, even when the rotary lever 24 is operated for a long time, the rotary lever 24 is always operated without running out of grease.
4 has the effect of being smoothly rotated.

Furthermore, the contact portion 24A of the rotating lever 24 was conventionally formed by twisting the other end of the rotating lever 24 and plastically deforming it, and the deformed portion was extremely brittle. The abutting portion 24A in the rotation lever 24 is a metal material constituting the rotation lever 24.
Because it is formed by being crushed and plastically deformed into a plane perpendicular to the rotation direction of 4, it has extremely high strength and has sufficient durability even when used continuously for a long time. be. Moreover, the processing itself is easy and can be performed with high precision.

Furthermore, even if the free end of the Bourdon tube 5 is displaced excessively (overtravel), the free end of the Bourdon tube 5 is separated from one end side of the rotating lever 24, or the contact 24A is moved away from the contact 27 of the micro switch 21. There is no possibility that excessive force will be applied to each part including the micro switch 21. Therefore, even when the free end is excessively displaced, there is no risk of damage to the various parts, and a highly safe Bourdon tube switch can be provided.

Further, the Bourdon tube 5 is arranged eccentrically on the other longitudinal side of the base 1 with the C-shaped opening facing one longitudinal side of the base 1, and is supported on the plate 13 and the plate 13. The inner mechanism consisting of the micro switch 21 and the rotating lever 24 is disposed extending from the inside of the Bourdon tube 5 to the C-shaped opening to the one side in the longitudinal direction of the base 1. This has the effect that the space of the switch can be effectively used, and the volume of the entire Bourdon tube switch can be extremely miniaturized.

In addition, in implementation, the mounting position of the rotating lever 24 and the sleeve 23 is not limited to the case where the sleeve 23 is biased to one side and the displacement of the free end of the Bourdon tube 5 is expanded; for example, the mounting position of the rotating lever 24 and the sleeve 23 is The free end may have a structure in which the displacement of the free end is not particularly increased, such as by being provided at the center in the longitudinal direction of the free end. In this case as well, the deadband difference can be eliminated or reduced by the action of the coil spring 31.

Further, the spring mounting hole 28 may be drilled only at one location, but if a plurality of spring mounting holes 28 are provided, the dead band difference can be adjusted without replacing the coil spring 31.

Further, the biasing means for adjusting the load applied from the Bourdon tube 5 to the contactor 27 is the coil spring 31.
For example, the spring may be a torsion coil spring wound around the support shaft 22.

Furthermore, the rotating lever 24 is not limited to being supported on the plate 13, but may be supported directly on the base 1. However, when supported on the plate 13, it is easy to set and adjust the detection pressure, and moreover, the rotary lever 2 is mounted on the plate 13.
Since the plate 13 can be mounted on the base 1 after the micro switch 4 and the micro switch 21 are mounted, assembly is easy.

Furthermore, the contact portion 24A formed on the other end of the rotating lever 24 is not limited to being formed by being crushed as in the above embodiment, but may be formed by twisting the other end of the rotating lever 24. It may also be something that is done. however,
According to the contact portion 24A, the above-mentioned effects can be obtained.

In addition, the Bourdon tube 5 is not limited to the C-shaped one.
It may be spiral-shaped, and the switch portion is not limited to the micro switch 21 but may be other types of switches.

As mentioned above, the operation error based on the dead band difference of the switch part is reduced, enabling high-precision operation, and the Bourdon tube is a safe Bourdon tube with no risk of damage to any part even if the free end of the tube is displaced excessively. We can provide a type switch.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the overall structure of an embodiment of the Bourdon tube switch according to the present invention, FIG. 2 is a plan view of the embodiment with the cover removed, and FIG.
The figure is an enlarged sectional view taken along the line - in FIG. 2, FIG. 4 is a perspective view showing the rear side of the embodiment, and FIG. 5 is a plan view showing the adjustment mechanism for the mounting position of the plate in the embodiment. be. 1... Base, 5... Bourdon tube, 13... Plate, 14... Rotation center hole, 16... Long hole, 1
8... Adjustment screw, 21... Micro switch as a switch part, 22... Support shaft as a rotating shaft,
23... Sleeve as a bearing part, 24... Rotating lever, 24A... Contact part, 25... Recessed part, 26
... Lubricant, 27 ... Contact, 28 ... Spring mounting hole, 31 ... Coil spring as biasing means, 33
... Displacer, 41 ... Installation protrusion.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a Bourdon tube type switch that detects the state of the fluid to be measured in the Bourdon tube by moving the switch part toward and away from the switch part by the displacement of the Bourdon tube, one end side is adjusted according to the distance from the center of rotation. a rotating lever capable of transmitting the displacement of the bourdon tube to the other end and whose one end comes into contact with the free end of the Bourdon tube, and urging means for rotating the rotating lever in a direction in which it comes into contact with the free end. and is capable of contacting the other end of the rotary lever when the rotary lever rotates in the direction of contacting the free end, and is capable of separating from the other end when the free end is excessively displaced. A Bourdon tube type switch characterized by having a switch part. (2) Utility Model Registration The Bourdon tube type switch according to claim 1, characterized in that the biasing means is attached to the rotating lever so that its attachment position can be changed. (3) The Bourdon tube type switch according to claim 1 or 2, wherein the rotary lever is supported by a plate whose mounting position can be adjusted with respect to the Bourdon tube. . (4) Utility model registration Claims In any one of claims 1 to 3, the other end side of the rotary lever has a metal material constituting the rotary lever that corresponds to the rotation direction of the rotary lever. 1. A Bourdon tube type switch characterized in that a contact portion is formed which is crushed into a vertical planar shape and plastically deformed, and the rotary lever moves toward and away from the switch portion at this contact portion.