JP5499283B2 - Electric actuator - Google Patents

Description

  The present invention relates to an electric actuator capable of continuously changing a cross-sectional area of a flow path by, for example, rotating a valve body in a fluid pipe within a predetermined angle range and controlling a flow rate of a fluid flowing through the valve body. Is.

  Conventionally, as an electric actuator for rotating such a valve body, an output shaft connected to the valve body and transmitting a driving force from a built-in motor so as to rotate by a predetermined angle to the valve body, There has been known a configuration in which a shaft of a potentiometer for obtaining angle information of the output shaft is connected through a pair of gears (see, for example, Patent Document 1).

  According to this prior art, the output shaft is pivoted in a direction perpendicular to the upper and lower surfaces of the base portion by a pair of bearing portions spaced apart from each other at a predetermined interval below the plate-like base portion. It is attached to have.

  The output shaft is pivotally supported by a pair of bearings, but can be connected to a potentiometer via a pair of gears to convert a desired deceleration or speed increase from the output shaft to the potentiometer. Correspondingly, the gear ratio can be appropriately selected.

  As a result, the electric actuator can be shared except for the pair of gears, regardless of whether the output shaft is a 90 ° rotation type or a multi-rotation type.

  Furthermore, a configuration is also known in which the output shaft and the potentiometer are directly connected without using a pair of gears, thereby reducing the backlash generated from the pair of gears and improving the measurement accuracy of the rotation angle of the valve body (for example, , See Patent Document 2).

  The prior art will be described with reference to FIG.

  In FIG. 5, the electric control valve 101 includes a ball valve 102 (valve) installed in a pipe (not shown) and an electric operation unit 103 that opens and closes the valve.

  The ball valve 102 (two-way valve) includes a main body 121 in which a fluid flows from one end to the other end, a pair of valve seats 122 fixed to the inside, and an outer peripheral surface substantially in contact with the valve seat 122. A spherical valve body 123 and a valve rod 124 that rotates the valve body 123 within a range of about 90 ° are provided.

  The electric operation unit 103 has an output shaft 131 whose one end (lower end) is connected coaxially thereto.

  The output shaft 131 is rotatably supported on the plate 142 by a bearing 133 provided on the base 141 and a bearing 134 provided on the plate 142 at an intermediate portion thereof.

  Since the rotational force of the motor 105 is transmitted to the drive gear 132 fixed to the output shaft 131 via one or more reduction gears 106a to 106e, the output of the motor 105 is increased and the output shaft 131 is rotationally driven. Is done.

  Thereby, the opening / closing operation | movement of the valve body 123 can be performed smoothly.

  The control board 107 is supported by a plurality of (for example, two) stays 144 erected on the plate 142, and the output shaft 131 has a length that penetrates the control board 107.

  Further, at one end (upper end) which is the non-load side of the output shaft 131, a potentiometer for detecting the rotation angle and obtaining angle data corresponding to the current opening including the fully open position and the fully closed position of the valve. 109 is directly connected.

  Thereby, since the backlash which arises from a pair of gears as above-mentioned is lost, the detection accuracy of a rotation angle can be improved.

  In the potentiometer 109, the variable side terminal provided with the metal sliding contact is rotated on the resistor by the output shaft 131. Therefore, by connecting the variable side terminal to the control circuit 108, the current angle is obtained. An electrical signal corresponding to the data can be input to the control circuit 108.

  In addition, it has a built-in bearing that supports the shaft for detecting the rotation angle, and has a brush that continuously slides on the resistor in conjunction with the rotation of the shaft. A resistor-type rotation sensor that detects a rotation angle has also been known (see, for example, Patent Document 3).

  Japanese Patent Laid-Open No. 5-141558   JP 2009-115220 A   JP-A-6-185975

  However, in an electric actuator having a configuration in which the potentiometer shaft is directly connected to the non-load side of the output shaft as in the prior art, if an overload is applied to the output shaft so that the movement of the valve body to be blocked is hindered. Since the rotational force transmitted from the motor to the output shaft acts as a force for tilting the output shaft, there is a problem that the tilt of the output shaft tends to directly affect the tilt of the shaft of the potentiometer.

  For example, when a foreign object is caught between the valve body and the fluid piping, or when the valve body does not open and close smoothly due to deformation of the valve body itself, so-called overload, the output shaft connected to the valve body rotates. Because of the difficulty of movement, most of the force to be transmitted from the motor via one or more reduction gears as the driving force for rotating the output shaft is applied to the drive gear fixed to the output shaft from the reduction gear. Acts as a force to tilt the output shaft.

  On the other hand, in order to smoothly rotate the output shaft, the radial direction between the output shaft and a pair of bearing portions that support it in advance or between each bearing portion and the storage portion that stores the bearing portion. Since a slight gap is set for each of the two, the output shaft is inclined with respect to a virtual straight line connecting the bearing centers of the pair of bearing portions in the above-described situation.

  And since the main body of the potentiometer is mounted and firmly fixed on the control board or the like, the same inclination also occurs with respect to the main body of the potentiometer shaft directly connected to the output shaft.

  Therefore, when the output shaft is inclined, it is difficult to maintain the lower surface of the lower portion of the main body of the potentiometer and the shaft at an appropriate angle (for example, approximately right angle, the same applies hereinafter).

  As a result, the sliding state of the resistor of the potentiometer body and the brush linked to the shaft changes due to the inclination of the shaft, and there is a problem that accurate rotation angle measurement accuracy cannot be obtained.

  In addition, even if the potentiometer is not a resistance type and the magnetic sensor is attached to the shaft, the potentiometer is designed on the assumption that the main body and the shaft maintain an appropriate angle. .

  In any of the modes, the shaft is slidably attached to the main body via a bearing. Therefore, when the output shaft is tilted, the shaft directly connected to the shaft is also eccentric with respect to the bearing. For this reason, there has been a concern that the bearings and the shaft may be worn and the service life may be shortened.

The present invention is intended to solve the conventional problems, and an object thereof is to provide an electric activator Interview mediator having a holder which is capable of displacing the rotation angle detecting device according to the inclination of the output shaft.

In order to solve the above-described conventional problems, an electric actuator according to the present invention includes a base portion, an output shaft having an axis of rotation or rotation in a direction orthogonal to the base portion, and an output below the base portion. Rotation angle detection that detects the rotational displacement of the output shaft connected to a pair of bearings spaced apart at a predetermined interval so as to pivotally or rotatably support the shaft and the output shaft on the non-load side a device, an electric activator Interview error over data that includes a holder for supporting the rotation angle detecting device, retainer, the output shaft is predetermined for the virtual straight line connecting the bearing centers of the pair of bearing portions It is characterized by having a passive part that displaces according to the inclination when tilted more than an angle, and a mounting part that displaces the main body of the rotation angle detecting device by interlocking with the passive part.

  According to this configuration, an overload that impedes the movement of the valve body to close is applied to the output shaft, and the rotational force transmitted from the motor to the output shaft acts as a force to tilt the output shaft. However, the effect that the inclination of the output shaft does not directly affect the inclination of the shaft of the rotation angle detection device can be obtained.

  That is, most of the force that should be transmitted from the motor via one or more reduction gears as the driving force for rotation of the output shaft tilts the output shaft relative to the drive gear fixed to the output shaft from the reduction gear. Even if the output shaft is tilted, the rotation angle detecting device is displaced according to the magnitude of the tilt, so that the tilt of the shaft with respect to the main body of the rotation angle detecting device is reduced.

  That is, the rotation angle detection device is held by the holder while maintaining an appropriate angle between the main body and the shaft.

  As a result, the sliding contact state between the resistor of the main body of the rotation angle detection device and the brush interlocked with the shaft is less changed, so that more accurate measurement accuracy of the rotation angle can be obtained.

  In addition, the wear of the shaft and the bearing due to the contact of the shaft with each other is reduced, and there is less concern about shortening the service life.

  In addition to the above-described configuration, the electric actuator according to the present invention is configured such that the mounting portion of the holder has a rotation angle detection connected to the main body of the rotation angle detection device and the non-load side of the output shaft according to the displacement of the passive portion. It is preferable to displace the main body of the rotation angle detection device so that the angle with the shaft of the device is maintained in a state before the output shaft is tilted beyond a predetermined angle.

  Thereby, a rotation angle detection apparatus is hold | maintained, maintaining the appropriate angle of a main body and a shaft with a holder.

  As a result, the sliding contact state between the resistor of the main body of the rotation angle detection device and the brush interlocked with the shaft is less changed, so that more accurate measurement accuracy of the rotation angle can be obtained.

  In addition, the wear of the shaft and the bearing due to the contact of the shaft with each other is reduced, and there is less concern about shortening the service life.

  In addition to the above configuration, the electric actuator of the present invention includes a fastening portion fastened to the base portion, and an elastic member that connects between the mounting portion and the fastening portion, and an intermediate portion of the elastic member. It is preferable that the part is provided with a passive part.

  According to this configuration, since the mounting portion and the fastening portion are connected by the elastic member, the mounting portion can be easily displaced according to the inclination of the output shaft, and overload of the output shaft is eliminated. If it is done, it will be easy to restore the normal state without inclination.

  In other words, during operation of the electric actuator, the rotation angle detector is held while maintaining the proper angle between the main body and the shaft by flexing the retainer so that it can be restored via the passive part according to the slight inclination of the output shaft. The

  In the electric actuator of the present invention, in addition to the above-described configuration, the holder is formed of a flat metal member having a bent portion at at least three locations, the bent portion at one end forms a fastening portion, and the other end It is preferable that the bent portion constitutes the mounting portion, and the bent portion having the middle portion opened constitutes the passive portion.

  According to this configuration, a simple holder can be easily manufactured by performing a predetermined bending process on a flat metal member.

  In addition, in order to constitute the passive portion, by providing a bent portion that opens the middle part of the metal member, not only the elasticity in the direction in which the main plate bends but also the elasticity in the direction in which the main plate twists. Since it becomes easy to obtain, the effect that it becomes easy to displace a passive part according to the inclination of an output shaft is acquired.

According to the electric actuator of the present invention can provide an electric activator Interview mediator having a holder that can hold while maintaining the body and proper angular shaft of the rotation angle detecting device.

The fragmentary sectional view of the electric actuator in an embodiment of the invention The whole perspective view of the holder in an embodiment of the invention The fragmentary sectional view which shows the mounting state of the holder in embodiment of this invention (A) Schematic plan view showing the direction in which the passive portion of the holder is displaced with respect to the drive gear and the reduction gear, (b) Partial enlarged schematic view showing the meshing state of the drive gear and the reduction gear Cross section of conventional electric control valve

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  Here, FIG. 1 is a partial sectional view of the electric actuator according to the embodiment of the present invention, FIG. 2 is an overall perspective view of the holder according to the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. 4A is a partial cross-sectional view showing a mounting state of the holder in the embodiment, and FIG. 4A is a schematic plan view showing a direction in which the passive portion of the holder is displaced with respect to the drive gear and the reduction gear, and FIG. These are the partial expansion schematics which show the meshing state of a drive gear and a reduction gear.

  First, as shown in FIG. 1, in the electric actuator 10, the plate-like base portion 11 extending in the horizontal direction is arranged in the horizontal direction.

  And since the gasket 12 which has flexibility is inserted | pinched between the level | step-difference part of the outer peripheral part of the base part 11, and the upper cover part 13, the airtightness with the exterior is maintained favorable.

  The base portion 11 is formed of a relatively rigid material such as ADC (aluminum die-cast) or S45C (carbon steel with a carbon addition amount of 0.45%), and is disposed on the upper portion thereof. The motor 14 and the reduction gear 32 (see FIG. 4A) disposed at the lower portion have a predetermined strength so as to be interlocked with each other.

  Then, a round opening 11a (see FIG. 3) is formed slightly on the left side from the center of the base portion 11, and the output shaft 15 has a rotation axis in a direction (vertical direction) perpendicular to the upper and lower surfaces of the base portion 11. Is rotatably inserted.

  Here, when predetermined power is supplied from an external AC power source to an input terminal (not shown) of the cable 17 connected to the cable connector 16, the power is shown by a two-dot chain line. And then supplied to the control panel 19 after being converted to a predetermined voltage.

  If it does so, the motor 14 will generate | occur | produce the predetermined rotational drive force of forward rotation or reverse rotation according to the control signal input from another cable (not shown) different from the cable 17 from the outside.

  Next, the rotational driving force of the motor 14 is transmitted to a motor gear 31 (see FIG. 4A) that is directly connected to a rotating shaft (not shown) of the motor 14.

  Next, the rotational driving force of the motor gear 31 is finally driven directly to the output shaft 15 via the reduction gear 32 (see FIG. 4A) disposed below the base portion 11. (See FIG. 4A).

  At that time, the rotational driving force of the motor 14 is increased to a predetermined torque in accordance with the combination of the motor gear 31, the reduction gear 32 and the driving gear 30 and the gear ratio thereof, and finally transmitted to the output shaft 15.

  Thereby, it converts into the driving force which rotates the valve body (not shown) etc. which are connected to the load side (lower side in FIG. 1) of the output shaft 15.

  On the other hand, the shaft 20a (see FIG. 3) of the rotation angle detection device 20 is connected to the non-load side (upper side in FIG. 1) of the output shaft 15 via a coupling member 28 (see FIG. 3) (referred to as direct connection). Therefore, the displacement of the rotation angle of the output shaft 15 can be accurately detected.

  Then, the rotation angle detection device 20 outputs a voltage or current signal corresponding to the displacement of the rotation angle of the shaft 20 a to the control panel 19.

  Next, the control panel 19 performs predetermined processing according to the voltage or current signal output from the rotation angle detection device 20 and the control signal input from the outside via another cable, and finally the output shaft 15 The desired rotation control is performed.

  Further, since the periphery of the control panel 19 is surrounded by the insulating cover 21, it is possible to prevent electrical and mechanical contact due to the influence of vibration during startup.

  Here, the pair of bearing portions 22 arranged in the vertical direction indicated by broken lines are both positioned below the base portion 11, and a position where the axis of the output shaft 15 is orthogonal to the upper and lower surfaces of the base portion 11 can be secured. Thus, for example, they are spaced apart at a predetermined interval of 30 mm to 100 mm.

  Thus, the output shaft 15 is pivotally supported by the pair of bearing portions 22 so as to be rotatable about a virtual straight line L1 (a single-dot chain line) connecting the bearing centers.

  On the other hand, the holder 25 supports the main body of the rotation angle detection device 20 so that the shaft 20a (see FIG. 3) of the rotation angle detection device 20 is positioned on the rotation axis of the output shaft 15 (on the virtual straight line L1). doing.

  Further, two fastening portions 25 a (see FIG. 2) located at the lower portion of the holder 25 are fastened to the upper surface of the base portion 11 by two fixing screws 26 arranged side by side.

  Thereby, the holder 25 is fixed to the upper part of the base part 11 so that the longitudinal direction (vertical direction) is parallel to the rotation axis of the output shaft 15 (virtual straight line L1).

  With the above configuration, it is possible to connect the non-load side of the output shaft 15 and the shaft 20a of the rotation angle detection device 20 on the same axis.

  In addition, the holder 25 holds the rotation angle detection device 20 while maintaining an appropriate angle (for example, substantially right angle) between the main body and the shaft 20a.

  As a result, since the change in the sliding contact state between the resistor in the main body of the rotation angle detection device 20 and the brush linked to the shaft 20a is reduced, the rotation angle detection device 20 accurately detects the displacement of the rotation angle of the shaft 20a. It can be done.

  Further, the operator can easily sense the state of the opening degree of the output shaft 15 by observing the opening degree display unit 23.

  Thereby, even if the operator is in a state where no electric power or a control signal is given from the outside, the opening degree of the output shaft 15 while manually turning the manual operation shaft 24 attached so as to protrude downward from the base portion 11. Can be adjusted.

  Therefore, it is possible to easily cope with maintenance and troubleshooting of the valve body connected to the load side of the output shaft 15.

  Next, the basic configuration of the holder 25 will be described with reference to FIG.

  First, the holder 25 has a flat plate shape so that the cross-sectional shape in the longitudinal direction (vertical direction) is a rectangle having a plate thickness of 1.0 to 2.6 mm and a width of 20.0 to 60.0 mm. It is comprised from the metal member.

  And the holder 25 has a bending part in at least three places, the bending part of a lower end comprises the fastening part 25a, and the bending part of an upper end has the mounting part 25b which mounts the main body of the rotation angle detection apparatus 20. The bent part which comprises and opened the intermediate part comprises the passive part 25c.

  Here, although the passive part 25c is provided in the intermediate part of the mounting part 25b and the fastening part 25a, it is integrally formed in the main flat plate 25d which is an elastic member.

  Further, these three bent portions are all bent at a substantially right angle with respect to the main flat plate 25d extending in the longitudinal direction (vertical direction), and the base portion thereof is plastically deformed. It is kept.

  The mounting portion 25b and the passive portion 25c are bent in the same direction, but the fastening portion 25a is bent in a direction opposite to the direction.

  In particular, the passive portion 25c has a portion of the main flat plate 26d that connects the mounting portion 25b and the fastening portion 25a cut into an upward U-shape, and that portion is cut off from the main flat plate 25d and bent at a right angle. A rectangular opening 25e is formed simultaneously with the processing.

  By forming the opening 25e, the ratio of the length in the width direction and the length in the plate thickness direction in the orthogonal cross-sectional shape is in the range of 1: 1 to 3: 1 on both sides in the width direction of the main flat plate 25d. A rectangular connecting portion 25f is provided.

  The fastening portion 25a is formed with two fastening holes 25g through which the aforementioned fixing screws 26 (see FIGS. 1 and 3) are inserted.

  Furthermore, the mounting portion 25b is provided with a circular opening 25h for fitting the main body of the rotation angle detection device 20, and the passive portion 25c is provided with a sliding contact member 27 (see FIG. 3) such as a split bush. A circular opening 25i for press-fitting is provided.

  The metal material of the holder 25 is preferably a SECC (galvanized) steel plate or stainless steel for springs, and by selecting such a metal material, a predetermined elasticity is obtained in the main flat plate 25d and the connecting portion 25f. In addition, press working such as drilling and bending is easy.

  Further, even if a relatively large force that tilts the output shaft 15 acts on the holder 25, the function as an elastic member can be effectively exhibited.

  In other words, when the output shaft 15 is inclined more than a predetermined angle, the passive portion 25c is displaced according to the inclination of the output shaft 15, and the mounting portion 25b interlocked with the passive portion 25c can be displaced.

  In addition, when the force for tilting the output shaft 15 is released (overload is eliminated), it is easy to restore the natural state without falling down.

  In other words, the mounting portion 25b is displaced in the same direction as the passive portion 25c as the pendulum operates with the fastening portion 25a as a fulcrum by the elastic deformation of the main plate 25d by interlocking with the passive portion 25c, and the output shaft 15 is tilted. When the applied force is released (overload is eliminated), the restoring force of the main flat plate 25d naturally returns to the original position before the displacement.

  Further, as described above, the passive portion 25c is constituted by a bent portion that opens an intermediate portion of the main flat plate 25d that is an elastic member that connects the mounting portion 25b and the fastening portion 25a.

  Accordingly, the main flat plate 25d also has connecting portions 25f of elastic members on both sides in the width direction, so that the main flat plate 25d has a longitudinal direction (vertical direction) as well as a direction in which the main flat plate 25d tilts. It is also easy to obtain elasticity in a direction that twists as a virtual central axis.

  Thereby, even if the holder 25 is a flat metal member, when the range of the elastic direction is expanded and the output shaft 15 is inclined at a predetermined angle or more, the passive portion 25c is displaced according to the inclination. The effect that it becomes easy is acquired.

  As described above, when an overload is applied to the output shaft 15, most of the force to be transmitted from the motor 14 as the driving force for rotating the output shaft 15 via the reduction gear 32 is from the reduction gear 32. This acts as a force for tilting the output shaft 15 with respect to the drive gear 30 fixed to the output shaft 15.

  Even when the output shaft 15 is tilted by a predetermined angle or more, the mounting portion 25b is displaced in conjunction with the passive portion 25c, so that the main body of the rotation angle detecting device 20 can be displaced according to the tilt. .

  Thereby, the inclination of the shaft 20a (refer FIG. 3) with respect to the main body of the rotation angle detection apparatus 20 is reduced.

  In other words, when the electric actuator 10 is actuated, when the output shaft 15 is inclined at a predetermined angle or more, the main plate 25d of the holder 25 bends reversibly via the passive portion 25c according to the inclination, thereby rotating the rotation angle. The detection device 20 is held by the holder 25 while maintaining a proper angle between the main body and the shaft 20a.

  Note that the appropriate angle between the main body of the rotation angle detection device 20 and the shaft 20a in the present embodiment is an angle before the output shaft 15 is inclined more than a predetermined angle, and the rotation between the lower surface of the main body and the shaft 20a. This is an angle at which the angle with the axis of movement is substantially a right angle.

  Next, with reference to FIG. 3, the mounting state of the holder 25 and its operation will be described in detail.

  Here, although the cross section of the holder 25 is shown by hatching, the holder 25 has two fastening holes 25g (see FIG. 2) in a state where the lower surface of the fastening portion 25a positioned below is in contact with the upper surface of the base portion 11. ) Is firmly fastened to the base portion 11 by a fixing screw 26 inserted therethrough.

  As a result, the holder 25 is erected on the upper portion of the base portion 11 so that its longitudinal direction (vertical direction) is parallel to the rotational axis of the output shaft 15.

  On the other hand, a nut 20d is screwed into the male screw portion 20c in a state where the main body lower portion 20b of the rotation angle detecting device 20 is fitted and inserted into the circular opening portion 25h (see FIG. 2) of the mounting portion 25b positioned above. It is tightened.

  At that time, since the mounting portion 25b and the locking washers fitted under the mounting portion 25b are sandwiched between the main body of the rotation angle detection device 20 and the nut 20d, the rotation angle detection device 20 is mounted. Fastened to the portion 25b.

  Further, as described above, the circular opening 25i (see FIG. 2) is formed in the passive portion 25c in advance, and a sliding contact member 27 such as a split bush with a hook at the lower end is formed in the circular opening 25i. It is fitted by press fitting.

  Further, the lower end surface of the shaft 20a protruding from the lower body portion 20b of the rotation angle detection device 20 is brought into contact with the upper end surface on the opposite side of the output shaft 15, and the shaft 20a and the output shaft 15 are set screws (see FIG. (Not shown), the shaft 20a and the output shaft 15 are connected (also referred to as direct connection) on the same rotational axis.

  Furthermore, a C-ring 29 for restricting the position in the vertical direction is inserted into the outer peripheral recess of the part slightly lowered from the center of the coupling member 28.

  The coupling member 28 is disposed so as to be in sliding contact with the inner peripheral side of the sliding contact member 27.

  Here, for example, if the total length of the split bush constituting the sliding contact member 27 is set to 7 mm and the inner diameter is set to φ12 mm, the dimensional difference between the inner diameter and the outer diameter of the coupling member 28 is preferably set to 1 μm to 22 μm. .

  Usually, the output shaft 15 is assumed to be inclined in a range of 0.08 to 0.8 degrees due to a tolerance between the pair of bearing portions 22 and the output shaft 15. For example, it corresponds to displacement in the direction of arrow M by a length of about 40 μm to 400 μm.

  For this reason, by setting the dimensional difference between the inner diameter of the sliding contact member 27 and the outer diameter of the coupling member 28 in the above-described range, the inclination of the output shaft 15 is in the range of 0.08 to 0.8 degrees. However, the passive portion 25c can be sufficiently displaced according to the inclination.

  Moreover, in the holder 25, if the total height H from the fastening portion 25a to the mounting portion 25b is set to 50 mm, the height h from the fastening portion 25a to the passive portion 25c is 50% to the total height H with respect to the total height. It is preferable to set it in the range of 70%.

  Within this range, in the holder 25, the passive portion 25c and the mounting portion 25b are displaced in the same direction as the operation of the pendulum with the fastening portion 25a as a fulcrum by the elastic deformation of the main flat plate 25d, but the output shaft 15 is tilted. When the applied force is released (overload is eliminated), the restoring force of the main flat plate 25d naturally returns to the original position before the displacement.

  As is apparent from this figure, when the output shaft 15 is tilted so as to fall in the direction indicated by the arrow M, for example, the coupling member 28 is also displaced in the same direction, and the coupling member 28 and the sliding member 27 are moved. Because of the sliding contact (contact while sliding), the passive portion 25c is also displaced in substantially the same direction by the force that tilts the output shaft 15.

  For smooth sliding contact between the two, it is preferable to select a molybdenum coating agent or a copper-based porous material as a material for the sliding contact member 27, and a material for the coupling member 28 is more preferable than that. It is preferable to select carbon steel such as SS400 and S45C having high hardness.

  With the configuration as described above, when the output shaft 15 is inclined at a predetermined angle or more with respect to a virtual straight line L1 (see FIG. 1) connecting the bearing centers of the pair of bearing portions 22, the output shaft 15 is inclined. Accordingly, the passive portion 25c is displaced, and the mounting portion 25b is displaced in conjunction with the displacement.

  That is, when the electric actuator 10 is actuated, if the output shaft 15 is tilted by a predetermined angle or more, a force for tilting the output shaft 15 acts on the sliding contact member 27 from the coupling member 28, and the tilt Since the main plate 25d of the holder 25 is elastically deformed in the direction of tilting or twisting via the passive part 25c according to the size and direction of the mounting part 25b, the mounting part 25b is also displaced in substantially the same direction as the passive part 25c.

  Thereby, the holder can hold | maintain the rotation angle detection apparatus 20, maintaining the appropriate angle of the main body and the shaft 20a.

  Next, with reference to FIGS. 4A and 4B, the direction in which the passive portion 25c is displaced with respect to the arrangement of the drive gear 30 fixed to the output shaft 15 and the reduction gear 32 meshing therewith will be described.

  In this figure, the drive gear 30 fixed to the output shaft 15 and the reduction gear 32 that meshes with the drive gear 30 are both spur gears, and are schematic views of the positional relationship in the displacement direction of the passive portion 25c as viewed from above. Show.

  As shown in FIG. 4A, for example, when a valve body (not shown) is closed, the motor gear 31 directly connected to the rotating shaft of the motor 14 rotates in the clockwise direction indicated by the arrow, and its rotational driving force. Is transmitted as a driving force for rotating the drive gear 30 of the output shaft 15 in the clockwise direction via the reduction gear 32 rotating in the counterclockwise direction.

  Here, the imaginary straight line L2 indicated by the alternate long and short dash line is a straight line connecting the axes of the drive gear 30 and the reduction gear 32 on the same orthogonal cross section, and the direction in which the passive portion 25c is displaced with respect to the imaginary straight line L2. Is indicated by an arrow T.

  Since the motor gear 31, the reduction gear 32, and the drive gear 30 are all disposed in a space sandwiched between the pair of bearing portions 22 shown in FIG. 1, a valve element is interposed on the load side of the output shaft 16. When an overload is applied, the rotational force transmitted from the motor 14 to the output shaft 15 acts as a force for tilting the output shaft 15, so that an inclination with the load side of the output shaft 15 as a fulcrum occurs.

  Here, when the virtual straight line L2 is used as a reference, the angle θ in the displacement direction (the direction of the arrow T) of the passive portion 25c due to the inclination of the output shaft 15 is counterclockwise as shown in FIG. Since this corresponds to the meshing pressure angle α (angle between the virtual straight line L2 and the straight line L3) of the reduction gear 32 and the clockwise driving gear 30 meshing therewith, it falls within the range of the meshing pressure angle α from 0 degrees.

  The meshing pressure angle α is an angle formed by a radius line and a tangent to the tooth profile (straight line L3) at one point (usually a pitch point) of the tooth surface, which is shown in FIG. 4 (b). ing.

  That is, in the case of a spur gear, since the meshing pressure angle α is 20 degrees, the angle θ in the displacement direction of the passive portion 25c when the output shaft 15 is inclined at a predetermined angle or more is 0 degrees to 20 degrees. Will exist in the range.

  On the other hand, in the holder 25, elasticity in the direction of tilting so as to fall down is obtained most efficiently in the direction along the straight line L4 indicated by the two-dot chain line.

  However, as described above, the opening 25e is formed in the middle portion of the main flat plate 25d, and the connecting portions 25f are provided on both sides in the width direction, so that it is easy to obtain elasticity in the direction in which the main flat plate 25d is twisted. In the direction of arrow T, it has sufficient elasticity.

  As described above, most of the force to be transmitted from the motor 14 via the reduction gear 32 as the driving force for rotating the output shaft 15 is applied to the drive gear 30 fixed to the output shaft 15 from the reduction gear 32. When the output shaft 15 acts as a force to tilt the output shaft 15 and the output shaft 15 tilts more than a predetermined angle, the passive portion 25c can be efficiently displaced according to the tilt.

  Therefore, since the holder 25 can hold the rotation angle detection device 20 while maintaining an appropriate angle between the main body and the shaft 20a, the inclination of the shaft 20a with respect to the main body of the rotation angle detection device 20 is reduced accordingly.

  As a result, the sliding contact state between the resistor of the main body of the rotation angle detection device 20 and the brush linked to the shaft 20a is less changed, so that more accurate measurement accuracy of the rotation angle can be obtained.

  Further, the wear of the shaft 20a and the bearing (not shown) due to the contact of the shaft 20a with each other is reduced, and there is less concern about shortening the service life.

  The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. The technical scope disclosed in different embodiments, respectively. Modifications of the embodiment obtained by appropriately combining the means are also included in the technical scope of the present invention.

  For example, in the description of the present embodiment, the case of a valve stem 90 ° rotation type such as a ball valve has been described, but the present invention can be applied to a valve stem multi-rotation type such as a diaphragm valve.

  Therefore, the present invention can be applied regardless of whether the output shaft rotates or rotates.

  Further, as a method of connecting the shaft of the rotation angle detection device to the non-load side of the output shaft, in addition to connecting the output shaft and the shaft via a joint fitting such as a coupling member as described above, for example, caulking, welding Any other method such as bonding may be used.

  In addition, the mounting portion, the passive portion, and the fastening portion of the holder in the present embodiment are all bent at a substantially right angle with respect to the main plate of the holder that extends in the longitudinal direction (vertical direction), and are integrated as a whole. Although formed, each may be constituted by a separate member and connected by a method such as a joint fitting, caulking, welding, or adhesion.

  Furthermore, the holder in the present embodiment has been described in the case of a flat metal member. However, as long as a desired effect can be obtained, other shapes and materials such as resin may be used. One end thereof does not necessarily have to be fastened to the base portion.

  The electric actuator according to the present invention controls the flow rate of the fluid flowing through the valve body by continuously changing the cross-sectional area of the flow path, for example, by rotating the valve body in the fluid piping within a predetermined angle range. It is useful as an electric actuator that can be used.

DESCRIPTION OF SYMBOLS 10 Electric actuator 11 Base part 11a Opening 12 Gasket 13 Upper cover part 14 Motor 15 Output shaft 16 Cable connector 17 Cable 18 Power supply board 19 Control panel 20 Rotation angle detection apparatus 20a Shaft 20b Main body lower part 20c Male thread part 20d Nut 21 Insulating cover 22 A pair Bearing part 23 opening display part 24 manual operation shaft 25 holder 25a fastening part 25b attachment part 25c passive part 25d main plate 26e opening part 25f coupling part 25g fastening hole 25h, 25i circular opening part 26 fixing screw 27 sliding member 28 Coupling member 29 C ring 30 Drive gear 31 Motor gear 32 Reduction gear M, T Arrows L1, L2 Virtual straight line L3, L4 Straight line H Overall height h Height θ Angle α Engagement pressure angle

Claims (2)

A base portion, an output shaft having an axis of rotation or rotation in a direction orthogonal to the base portion, and a predetermined portion so as to pivotally or rotatably rotate the output shaft below the base portion. A pair of bearing portions spaced apart from each other, a rotation angle detection device that is connected to the non-load side of the output shaft and detects the rotational displacement of the output shaft, and a holder that supports the rotation angle detection device An electric actuator with
The holder is
When the output shaft is inclined at a predetermined angle or more with respect to a virtual straight line connecting the bearing centers of the pair of bearing portions, the rotation is performed by interlocking with a passive portion that is displaced according to the inclination and the passive portion. A mounting part for displacing the main body of the angle detection device,
A fastening portion fastened to the base portion, and an elastic member that connects between the mounting portion and the fastening portion, and includes the passive portion at an intermediate portion of the elastic member;
A bent portion comprising a flat metal member having bent portions at at least three locations, the bent portion at one end forming the fastening portion, the bent portion at the other end forming the mounting portion, and the intermediate portion being opened. Constituting the passive part,
Electric actuator characterized by The mounting portion of the holder is configured to determine an angle between a main body of the rotation angle detection device and a shaft of the rotation angle detection device connected to a non-load side of the output shaft according to the displacement of the passive portion. The electric actuator according to claim 1, wherein the main body of the rotation angle detecting device is displaced so that the output shaft is maintained in a state before being tilted more than the predetermined angle.

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