JP4365186B2 - Torque switch - Google Patents

Description

  The present invention relates to an improved torque switch used for an electric valve or the like.

  The motorized valve drive device has a limit switch that operates according to the amount of movement of the valve body, and shuts down the motor power supply when the set torque is reached for the purpose of preventing self-damage due to excessive output torque. Equipped with a torque switch.

  9 to 13 are diagrams for explaining the structure and operation of a conventional torque switch.

  9 is a schematic perspective view of an electric valve drive device (hereinafter referred to as an electric valve), FIG. 10 is a front view of a conventional torque switch, FIG. 11 is a plan view, and FIG. 12 is a right side view. FIG. 13 is an operation schematic diagram showing the torque switch developed in the rotational direction.

  As shown in FIG. 9, the electric valve (1) includes an electric motor (2), a worm (3) rotated by the electric motor (2), a worm wheel (4) and a stem rotated by the worm (3). A nut (5) is provided.

  A stem nut (5) that rotates integrally with the worm wheel (4) is screwed into a stem (7) that opens and closes the valve element (6).

  The shaft (8) of the worm (3) measures the absolute amount of rotation of the shaft (8), and the fully closed limit that stops the electric motor (2) at the fully closed and fully open positions of the valve body (6). The switch (9) and the fully open limit switch (10) are connected.

  The shaft (8) of the worm (3) is provided with a torque spring unit (11) that elastically locks the force applied in the thrust direction of the worm (3). The thrust force corresponding to the load resistance is elastically received.

  As a result, the worm (3) can move in the axial direction in proportion to the load torque, and the movement amount of the worm (3) in the axial direction is integrated with the worm (3) in the axial direction. The torque is transmitted to the torque switch (13) via the moving screw shaft (12).

  As shown in FIGS. 10 to 12, the torque switch (13) has a rack on the side of the screw shaft (12) that moves integrally with the worm (3) at the rear end of the input shaft (14). It has a pinion (15).

  The torque switch (13) has a rotating body (20) having a movable contact (18) below a terminal block (17) having a plurality of fixed contacts (16), and is rotatable about the input shaft (14). Is provided.

  The terminal block (17) is fixed to the upper end of the mounting plate (19) penetrating the input shaft (14) at the rear, and a plurality of fixed contacts (16) extending vertically are connected to the rotating body (20). It extends along the plane of rotation.

  The rotating body (20) has a substantially cylindrical shape that is rotatable about the axis of the input shaft (14), and spans between the front ends of a pair of fixed contacts (16), (16) on the circumferential surface. A short-circuit plate-like movable contact (18) is provided.

  The torque switch (13) has a symmetrical arrangement of the fixed contact (16) and movable contact (18), and can be switched in both the forward and reverse rotation directions of the input shaft (14). It is as.

  The rotating body (20) is maintained in a neutral position by a torsion spring (21) that is always set to a neutral position at the center of the left and right, and the normal position of the fixed contact (16) and the movable contact (18) is maintained. The connection state is set to the neutral position.

  A rotating plate (22) that rotates integrally with the rotation of the rotating body (20) is provided in front of the rotating body (20) through the input shaft (14).

  The rotary plate (22) is provided with a long hole (23) concentric with the input shaft (14) and arcuately symmetrical.

  A driving body (24) that rotates integrally with the input shaft (14) and rotationally drives the rotating body (20) is provided on the rear surface of the rotating plate (22).

  The driving body (24) can drive the rotating body (20) in both forward and reverse directions via a pointer (25) whose mounting position is adjustable in the arc-shaped elongated hole (23). .

  The pointer (25) projects on the rear surface of the rotating plate (22) onto a trajectory that passes when the driving body (24) rotates, and is driven by the set screw (26) through the arc-shaped slot (23). The body (24) is adjustable between a proximal position from a neutral position and a distal position.

  The pointer (25) is provided with an indicator projection (27) protruding from the long hole (23), and the pointer (25) is provided on the rotary plate (22) along the outer periphery of the long hole (23) by a scale (28). The fixed position of 25) can be read as a value corresponding to the set torque value.

FIG. 13 is an operation schematic diagram showing the torque switch (13) developed in the rotational direction.
In the schematic diagram, the same components as those described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  When the valve element (6) is driven in either the valve closing direction drive (A) or the valve opening direction drive (B) by the motor-operated valve (1), the worm (3) has an axis line according to the driving direction. The amount of movement is proportional to the output torque according to the magnitude of the load.

  The amount of rotation of the input shaft (14) depends on the amount of movement of the worm (3), that is, the torque value, and the amount of movement of the driving body (24) fixed to the input shaft (14) also depends on the worm (3). Corresponds to the following torque value.

  In FIG. 13, a valve closing direction driving torque characteristic curve (a) in which the moving amount of the driving body (24) related to the valve closing direction driving (A) is graphed from the valve fully open position to the valve fully closed position, A valve opening direction drive torque characteristic curve (b) in which the movement amount of the drive body (24) related to the opening direction drive (B) is graphed from the valve fully closed position to the valve fully open position is a rotation for attaching the pointer (25). It is shown corresponding to the plate (22).

  The pointer (25) is provided on the movement trajectory when the driving body (24) rotates, so that the driving body (24) and the pointer (25) come into contact with each other while the driving body (24) is rotating. The rotating plate (22) is rotated in the rotating direction of the driving body (24), and the rotating body (20) having the movable contact (18) is also rotated together, and the rotation is a predetermined movement amount (rotating Reaching the angle), the movable contact (18) bridging between the pair of fixed contacts (16) is released and the switch is opened.

  Note that the intermittent contact between the fixed contact (16) and the movable contact (18) includes a normally open contact and a normally closed contact, with the neutral position of the rotating body (20) being the normal state and the closed contact being the neutral position. The normally closed contact and the opened one are normally opened contacts, and the illustrated example shows a normally closed contact.

  The adjustment of the left and right pointers (25) and (25) is specified by design specifications because the torque characteristic curves (a) and (b) differ depending on the type and structure of the valve body (6), or Sometimes it is done on site.

  In this adjustment, the pointers (25) and (25) have a sufficient margin (c) with respect to the transient maximum values in the torque characteristic curves (a) and (b) and the intermediate stable torque value, and The abnormal torque value is set at a place where it can react promptly.

  At the time of this adjustment, the pointing projection (27) and the scale (28) of the pointer (25) are used to read the recorded value when the pointer (25) is adjusted.

  The torque switch shown in FIGS. 9 to 12 is of the model number SMB-000 which is the product of the present applicant.

  Most motor-operated valves use a limit switch for drive control of the drive motor in normal full-open or full-close operation, and torque switch is used when excessive torque is generated due to deterioration of sliding parts or foreign object biting. Is now working.

  In such a case, when the torque switch stops, the cause of excessive torque is removed, safety is ensured, and then the operation is started again. Prevent stable and planned operation and cause loss of operational opportunities such as pipelines that use valves.

  The torque characteristics of the electric valve vary with time depending on the type and structure of the valve used, and also vary with time depending on the frequency of opening and closing of the valve.

  Therefore, even if the setting position of the pointer is set with sufficient allowance in the initial setting of the torque switch, the margin of effective operating torque varies in each valve. Even in the case of torque fluctuation that does not operate the switch, there is a problem that the torque switch operates.

  Such an inconvenience is caused by the structure, usage environment, and history of each valve. It is difficult to predict in advance, and it is too time-consuming to readjust the pointer during regular inspection.

The present invention has been made in view of the above circumstances, and in the normal operation of the motor-operated valve, the fact that the margin of the operating torque of the torque switch is narrowed,
It is an object of the present invention to provide a torque switch that can prevent an inconvenient operation by providing proximity measurement means for detecting the degree of approach between a drive body and a pointer.

  According to the present invention, the above problem is solved as follows.

(1) A terminal block provided with a fixed contact is provided with a movable contact and rotates to rotate the fixed contact and the movable contact so as to control the opening and closing of the fixed contact and the movable contact. A pointer provided on the rotating plate is adjustable, and is fixed to a rotating shaft that rotates in accordance with the output torque of the motor-operated valve. The rotating body is rotated by contacting the pointer in accordance with the output torque. In the torque switch provided with the driving body, proximity detecting means for detecting the degree of approach between the driving body and the pointer is provided between the driving body and the pointer.

(2) In the above item 1, the proximity detection means is a mechanical switch provided between the driver and the pointer.

(3) In the above item 1, the proximity detection means is an optical switch provided between the driver and the pointer.

(4) In the above item 1, the proximity detecting means is an electromagnetic switch provided between the driver and the pointer.

(5) In any of the above items (1) to (4), the proximity detection means can adjust the proximity detection distance between the driver and the pointer.

(6) In any one of the above items (1) to (5), the proximity detection means can detect the proximity of the driver and the pointer at a plurality of detection points.

  According to the present invention, the following effects can be achieved.

(1) According to the first aspect of the present invention, it is possible to detect that the opening / closing operation (torque characteristic) of the motor-operated valve is approaching the set torque before the torque switch detects the set torque and performs the emergency operation. Therefore, maintenance and inspection can be performed at an early stage to avoid sudden emergency operation.
Further, since it is detected that the set torque is approached before reaching the set torque, it is not necessary to set the margin width strictly. Therefore, when adjusting the set torque (adjusting the pointer), it is not necessary to predict the change over time in the torque characteristics of the motorized valve, and the initial setting is simplified, and experience and skill are required to adjust the set torque. This eliminates the need for motorized valve installation and maintenance.

(2) According to the invention described in claim 2, a torque switch including a reliable proximity detecting means capable of reliably guaranteeing operation even in a bad environment such as a temperature environment, a high voltage environment, an electromagnetic noise environment, and a radioactive environment. Is provided.

(3) According to the invention described in claim 3, a torque switch provided with a small, light and compact proximity detecting means is provided.

(4) According to the invention described in claim 4, a torque switch provided with a highly reliable proximity detecting means is provided in a dusty environment such as dust or dust or in a high humidity environment.

(5) According to the invention described in claim 5, since the detection distance detected by the proximity detection means can be adjusted, a torque switch that can be applied universally to various valves and motor-operated valves having different valve structures. Can be provided.

(6) According to the invention described in claim 6, since the approach detecting means detects the degree of approach between the pointer and the driving body at a plurality of points, it is possible to observe the speed of change over time of the torque characteristics in the motor-operated valve, and the torque characteristics. Therefore, it is possible to predict or schedule an appropriate time for maintenance and inspection, and perform maintenance and inspection suitable for the operating environment of the motor-operated valve.

  1 to 5 show an embodiment of the present invention.

  FIG. 1 is a front view of a torque switch (13A) according to a first embodiment of the present invention, and FIG. 2 is a bottom view thereof.

  The present invention relates to the improvement of the conventional torque switch (13). The same parts as those of the conventional torque switch (13) described above are denoted by the same reference numerals, and detailed description thereof is omitted.

The gist of the present invention is that the terminal block (17) provided with the fixed contact (16) is provided with the movable contact (18) and is rotated, thereby rotating the fixed contact (16) and the movable contact (18). A rotating body (20) that controls opening and closing, a pointer (25) that is adjustable on a rotating plate (22) that rotates integrally with the rotating body (20), and an electric valve (1) ) Is attached to the rotating shaft (14) that rotates according to the output torque of the motor (24), and a driving body (24) that contacts the pointer (25) and rotates the rotating body according to the output torque. In the torque switch (13)
Proximity detecting means (29) for detecting the degree of approach between the driving body (24) and the pointer (25) is provided between the driving body (24) and the pointer (25).

  The proximity detecting means (29) in the illustrated torque switch (13A) is a mechanical type in which a micro switch (30) is attached to the pointer (25) side, and a cam plate piece (31) is attached to the driver (24) side. An example of a switch is shown.

  FIG. 3 is an exploded perspective view of the left pointer (25) viewed from the rear lower surface when the microswitch (30) is attached to the pointer (25).

  The microswitch (30) is attached to the tip (25a) of the pointer (25) via the attachment bracket (32).

  The mounting bracket (32) has a base end (34) that is fastened by a screw (33) to the upper end (25a) of the pointer (25), and from the base end (34), the rotating plate (22) The microswitch support plate (35) is protruded more horizontally in the front.

  The microswitch support plate (35) is provided with a long hole (36) along its longitudinal direction. The micro switch (30) is adjusted to the long hole (36) by a screw (37) and a holding plate (39) provided with a screw hole (38) along the longitudinal direction of the long hole (36). Can be attached freely.

Since the tip (25a) of the pointer (25) is lower than the outer periphery of the rotating plate (22), the height adjusting plate (35) has a height that the microswitch support plate (35) gets over the outer periphery of the rotating plate (22). 40) is interposed between the base end (34) and the tip (25a) of the pointer (25).
Further, the bent portion (34a) provided on the side surface of the base end portion (34) is a detent.

  On the other hand, a mounting bracket (35) with different right and left sides is also provided on the upper end (25a) of the right pointer (25), and the microswitch (30) is attached.

  Both microswitches (30) and (30) have the operating roller (41) that operates the switch facing backward, and the contact surface of the operating roller (41) is slightly behind the rear surface of the rotating plate (22), It is attached.

  FIG. 4 is an exploded perspective view of the driving body (24) when the cam plate piece (31) is attached to the lower end (24a) of the driving body (24), as viewed from the rear lower surface.

  When viewed from the front in FIG. 1, the cam plate piece (31) is arcuate along the outer periphery of the rotating plate (22), and the first cam surface is symmetrical with the plate surface parallel to the rotating plate (22). (42) (42) and a second cam surface (43) projecting forward at the center lower portion between the first cam surfaces (42) and (42). The second cam The upper end (43a) of the surface (43) is horizontally bent backward, and the horizontal bent piece (44) is used as a base to the lower end (24a) of the drive body (24) via a set screw (45). It is screwed (see FIG. 4).

  In the neutral position of the driving body (24), the microswitches (30) and (30) attached to the pointer (25) move the actuating rollers (41) and (41) to the first as shown by the phantom lines in FIG. The cam surfaces (42) and (42) are in contact with each other.

  FIG. 5 is an operation schematic diagram showing the torque switch (13A) according to the present invention expanded in the rotational direction.

  In addition, the code | symbol shown in a schematic diagram attaches | subjects the same code | symbol about what shows the same thing as the said description, and the detailed description is abbreviate | omitted.

  When the driving body (24) is in the neutral position, the operating roller (41) of the micro switch (30) attached to the pointer (25) is the first cam plate piece (31) attached to the driving body (24). The micro switch (30) is in an inoperative state (off state) in contact with the cam surface (42).

  When the driving body (24) is rotated by torque output, the operating roller (41) comes into contact with the second cam surface (43) and presses the operating roller (41), the micro switch (30) is in the operating state ( ON state).

The timing when the microswitch (30) is activated is set to a detection distance (d) slightly before the driver (24) contacts the pointer (25).
The detection distance (d) is preferably between the margin width (c) for the torque characteristic curves (a) and (b). For this purpose, the microswitch (30) is adjustable in its attachment position to the pointer (25).

  The margin width (c) differs depending on the type and structure of the valve body (6), as in the torque characteristic curves (a) and (b). Adjusting the position of the pointer (25) is done on site.

  The detection distance (d) corresponding to the margin width (c) also varies depending on the size of the margin width (c). Therefore, in order to obtain the best effect, the torque characteristic curve (a ' ) (b ′) is preferably adjusted by electric power so as to be included in the detection distance (d).

  That is, if the detection distance (d) is brought closer to the margin width (c), it is sensed from the initial state of torque fluctuation, and if the detection distance (d) is reduced, the torque fluctuation having a large transient fluctuation is detected. Absorbs less effect.

  For the torque switch (31A) applied to the type and structure of the valve body (6), the detection distance (d) is fixed in advance, and the microswitch (30) is attached to the pointer (25). You can also.

  FIG. 6 shows an embodiment in which the proximity detection means (29) is an optical switch, with an operation schematic diagram similar to FIG.

In FIG. 6, a photocoupler (46) is attached to the pointer (25), and when the driving body (24) approaches the pointer (25), the photocoupler (46) is shielded. A shielding plate (48) to be inserted into the plate insertion slit (47) is attached.
The length of the detection distance (d) is the distance between the side surface of the driver (24) and the side surface of the pointer (25) at the time when the photocoupler (46) is blocked by the shielding plate (48). The distance between the contact surfaces (corresponding to the rotation angle corresponding to the torque value).

  FIG. 7 shows an embodiment in which the proximity detection means (29) detects the proximity of the driver and the pointer at a plurality of detection points. It is shown as an example.

In this example, a plurality of photocouplers (46a) and (46b) are arranged in parallel with the pointer (25).
The length of the shielding plate (48) is such that when the driving body (24) reaches the detection distance (c) before contacting the pointer (25), the optical coupling of the subsequent photocoupler (46b) is blocked. As it is.

  Thus, the preceding photocoupler (46a) detects the approach of the pointer (25) before the detection distance (c), and detects the approaching degree of the pointer (25) in two stages. .

  FIG. 8 shows an embodiment in which the proximity detection means (29) is an electromagnetic switch, with an operation schematic diagram similar to FIG.

  In FIG. 8, a reed switch (49) is attached to the pointer (25), and the reed switch (49) is activated when the driving body (24) approaches the pointer (25). A permanent magnet (50) is attached.

  The length of the permanent magnet (50) is such that the reed switch (49) close to the permanent magnet (50) when the driving body (24) reaches the detection distance (c) before it contacts the pointer (25). Is the length to operate.

  A Hall element can be used instead of the reed switch (49).

It is a front view of the torque switch concerning the 1st example of the present invention. Similarly, it is a bottom view. It is a disassembled perspective view which shows the point which attaches a microswitch to a pointer. It is a disassembled perspective view which shows the point which attaches a cam board to a drive body. It is an operation | movement schematic diagram of the torque switch which concerns on 1st Example of this invention. It is an operation | movement schematic diagram which shows the 2nd Example of this invention. It is an operation | movement schematic diagram which shows the 3rd Example of this invention. It is an operation | movement schematic diagram which shows the 4th Example of this invention. Schematic perspective view of electric valve drive device Front view of conventional torque switch Same top view Same right side view It is an operation | movement schematic diagram which expand | deploys and shows the conventional torque switch in a rotation direction.

Explanation of symbols

(1) Electric actuator for valve drive
(2) Electric motor
(3) Worm
(4) Worm wheel
(5) Stem nut
(6) Valve body
(7) Stem
(8) Axis
(9) Fully closed limit switch
(10) Full open limit switch
(11) Torque spring unit
(12) Screw shaft
(13) (13A) Torque switch
(14) Input shaft
(15) Pinion
(16) Fixed contact
(17) Terminal block
(18) Moving contact
(19) Mounting plate
(20) Rotating body
(21) Torsion spring
(22) Rotating plate
(23) Long hole
(24) Driver
(24a) Upper end
(25) Pointer
(26) Set screw
(27) Indicator projection
(28) Scale
(29) Proximity detection means
(30) Micro switch
(31) Cam plate
(32) Mounting bracket
(33) Screw
(34) Base end
(35) Microswitch support plate
(36) Long hole
(37) Screw
(38) Screw hole
(39) Holding plate
(40) Height adjustment plate
(41) Actuating roller
(42) First cam surface
(43) Second cam surface
(44) Horizontal bent piece
(45) Set screw
(46) (46a) (46b) Photocoupler
(47) Shield plate insertion slit
(48) Shield plate
(49) Reed switch
(50) Permanent magnet (a) (b) Torque characteristic curve (c) Margin (d) Detection distance

Claims (6)

A terminal block having a fixed contact is provided with a movable contact, and by rotating, a rotating body configured to control opening and closing of the fixed contact and the movable contact, and a rotating plate that rotates integrally with the rotating body A pointer provided in an adjustable manner, and a driving body fixed to a rotating shaft that rotates in accordance with output torque of the electric valve, and that rotates the rotating body in contact with the pointer in accordance with output torque. In the torque switch provided,
A torque switch, characterized in that proximity detection means for detecting the degree of approach between the driving body and the pointer is provided between the driving body and the pointer.   The torque switch according to claim 1, wherein the proximity detection means is a mechanical switch provided between the driver and the pointer.   The torque switch according to claim 1, wherein the proximity detection means is an optical switch provided between the driver and the pointer.   The torque switch according to claim 1, wherein the proximity detection means is an electromagnetic switch provided between the driving body and the pointer.   The torque switch according to any one of claims 1 to 4, wherein the proximity detection means can adjust a proximity detection distance between the drive body and the pointer.   The torque switch according to any one of claims 1 to 5, wherein the proximity detection means detects the proximity of the driving body and the pointer at a plurality of detection points.

Images