JP2007071357A - Electric actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric actuator capable of simplifying it by reducing the number of parts and reducing error in detection by detecting an operation angle of a rotary shaft directly to improve its reliability. <P>SOLUTION: This driving actuator 2 is constituted by and provided with a driving motor 11 in a housing, a reduction gear mechanism 12 for reducing speed of rotation of the driving motor 11 and transmitting the rotation to the rotary shaft 3, a joint 45 connection member for connecting the rotary shaft 3 with the reduction gear mechanism 12 and turning integrally with the rotary shaft 3, and an operation angle detection mechanism 12 for detecting an operation angle of the rotary shaft by turn of the connection member. The operation angle detection mechanism 13 is composed of a lever member 54 capable of swinging freely and two limit switches 60, 61 and is arranged in a case 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric actuator used for an electric valve, a damper, or the like that controls the flow rate of fluid such as hot water, cold water, and water vapor.

  Electric actuators that control the opening of valves and dampers that control the flow rates of various fluids include a drive motor that is driven by a drive signal from a control unit, and a valve or damper that is controlled by reducing the rotation of the drive motor. And a reduction gear mechanism that transmits to a rotation shaft, and an operation angle detection mechanism that detects the current operation angle (or operation range) of the rotation shaft and outputs it to the outside (see, for example, Patent Document 1).

  The electric actuator described in Patent Document 1 includes a planetary gear mechanism in which planetary gear units having a sun gear and a planetary gear are stacked in multiple stages to form a reduction gear mechanism, and the reduction gear mechanism is housed in a casing. Further, this casing is incorporated in the actuator cover, and the rotation of the drive motor is reduced by the reduction gear mechanism and transmitted to the valve shaft (rotary shaft). The shaft of the valve is connected to the gear base of the final stage of the planetary gear mechanism, and the rotation of this shaft is further transmitted to the rod through the transmission gear, and the rotation of this rod is an operating angle composed of a cam and a limit switch. By detecting by the detection mechanism, the operating angle of the shaft is indirectly detected, and the drive motor is driven and controlled by a detection signal of the operating angle detection mechanism.

JP 2002-31259 A

  However, since the electric actuator described in Patent Document 1 described above indirectly detects the operating angle of the rod as the operating angle of the shaft, it requires many parts such as a rod and a transmission gear, There is a problem that not only the structure becomes complicated, but also the actuator itself becomes large and heavy. Also, as the number of parts increases, the tolerances of individual parts increase accordingly, and the error increases, and the error in the stop position accuracy determined by the cam and limit switch increases. There was a problem of low reliability.

  The present invention has been made to solve the above-described conventional problems. The object of the present invention is to reduce the number of parts and enable simplification and to detect by directly detecting the operating angle of the rotating shaft. It is an object of the present invention to provide an electric actuator with small errors and improved reliability.

  In order to achieve the above object, a first invention includes a drive motor disposed in a housing, a reduction gear mechanism that reduces the rotation of the drive motor and transmits the rotation to the rotation shaft, the rotation shaft, and the reduction gear mechanism. A connecting member that rotates together with the rotating shaft, and an operating angle detecting mechanism that detects an operating angle of the rotating shaft by the rotation of the connecting member, the operating angle detecting mechanism being the reduction gear. It is provided in a case that houses the mechanism.

According to a second aspect of the present invention, the operating angle detection mechanism generates a first output at the maximum rotation position of the connecting member and generates a second output at the other rotation positions. ,
The minimum rotation position detecting means for generating the first output at the minimum rotation position of the connecting member and generating the second output at the other rotation positions, and the connection member rotated to the maximum rotation position. Sometimes, the connecting member receives a pressing force, transmits the pressing force to the maximum rotation position detecting means, and receives the pressing force by the connecting member when the connecting member rotates to the minimum rotation position. It is composed of a swingable lever member that transmits a pressing force to the minimum rotation position detecting means.

  According to a third aspect of the present invention, the maximum rotation position detection means and the minimum rotation position detection means are constituted by two limit switches disposed so as to face each other with the lever member interposed therebetween.

  According to the first aspect of the invention, the rotation of the connecting member directly connected to the rotating shaft is detected by the operating angle detecting mechanism provided in the case, so that it intervenes between the rotating shaft and the operating angle detecting mechanism. There are no parts, the number of parts can be reduced, detection errors are small, and reliability can be improved.

  According to the second invention, the member that transmits the rotation of the connecting member to the maximum rotation position detecting means and the member that transmits the minimum rotation position detecting means can be shared by the common lever member.

  According to the third aspect of the invention, the operating angle detection mechanism can be configured by the two limit switches facing each other and the swingable lever member.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
1 is a cross-sectional view showing an embodiment of an electric actuator according to the present invention, FIG. 2 is an exploded perspective view of main components of the actuator, FIGS. 3A to 3C are plan views of a joint, and a front view. 4A to 4C are a front view of the case, a plan view and a right side view, and FIGS. 5A and 5B are ON and OFF of the limit switch when the valve opening degree is 0%. FIGS. 6A and 6B are a plan view and a front view showing the ON / OFF state of the limit switch when the valve opening degree is 50%, and FIGS. 7A and 7B. ) Are a plan view and a front view showing the ON / OFF state of the limit switch when the valve opening degree is 100%.

  In FIG. 1, 1 is a ball valve to be controlled, and 2 is an electric actuator that drives and controls the ball valve 1 to adjust the valve opening.

  The ball valve 1 is a conventionally known two-way ball valve, and includes a rotating shaft 3 penetrating a cylindrical portion 4A integrally projecting on an upper portion of a valve body 4, and an outer end thereof is connected to the electric actuator 2, A ball plug (not shown) for controlling the flow rate of the fluid flowing through the ball valve 1 is provided at the end. The ball plug has a total operating angle of 90 °, a full closing angle of −45 °, and a full opening angle of + 45 °.

  1 to 4, the electric actuator 2 includes a housing 5 detachably fixed on the cylindrical portion 4 </ b> A, a drive motor 11, a reduction gear mechanism 12, and the rotating shaft 3 housed in the housing 5. The operating angle detecting mechanism 13 for detecting the operating angle is provided.

  The housing 5 is composed of an upper case 5A and a lower case 5B which are formed by being divided into upper and lower parts and integrally joined, and a yoke 14 is fitted into the lower case 5B from below and fixed. The yoke 14 is positioned and installed on a flange portion 4B provided integrally with the upper end of the cylindrical portion 4A, and is detachably fixed by an engagement element 15. A plurality of positioning pins 16 are integrally projected on the bottom surface of the yoke 14, and by fitting these positioning pins 16 into the recesses 17 formed on the upper surface of the flange portion 4B, the yoke 14 is fixed to the flange portion. Positioning can be performed with respect to 4B.

  The engagement element 15 is fitted and fixed inside the yoke 14, and engages with an engagement portion (not shown) provided on the flange portion 4B side, and the engagement element 15 is a flange portion. And an operation knob 18 for locking to 4B. The operation knob 18 protrudes to the outside from an opening 20 formed in the lower portion of the yoke 14. When the operation knob 18 is operated to release the engagement state of the flange portion 4 and the engagement element 15, the yoke 14 is flanged. It can be removed from the part 4B.

  The drive motor 11 is disposed on a horizontal mounting plate 21 provided in the upper case 5A with the output shaft 22 facing downward. The output shaft 22 of the drive motor 11 passes through a small hole 23 provided in the mounting plate 21 and projects below the mounting plate 21, and the rotation of the output shaft 22 is transmitted to the reduction gear mechanism 12 via a pinion 24. It is configured to be transmitted. The pinion 24 is fixed to the output shaft 22.

  The reduction gear mechanism 12 includes first and second planetary gear units U1 and U2 stacked in two stages, and is housed in a case 30.

  The first planetary gear mechanism U1 includes a gear 33 that meshes with the pinion 24, a gear 34 that is integrally provided on the lower surface of the gear 33, a gear 35 that meshes with the gear 34, and a lower surface of the gear 35. A sun gear 36 integrally provided on the side, four planetary gears 37 meshing with the sun gear 36, a sun gear 38 on which these planetary gears 37 are rotatably mounted, and the like. The gears 33 and 34 are integrally formed and are rotatably attached to the lower surface of the mounting plate 21. The gears 35 and 36 are also integrally formed, and are disposed together with the planetary gear 37 on a disk portion 38A of the sun gear 38 via a pin 42.

  Similarly, the second planetary gear mechanism U2 includes four planetary gears 39 meshing with the sun gear 38, a carrier 40 on which the planetary gears 39 are rotatably mounted, and the case 30. The inner teeth 42 (FIG. 3 (b)) formed and meshed with the planetary gear 39 are formed. A joint (connecting member) 45 is disposed between the carrier 40 and the rotating shaft 3.

  The joint 45 is a member for transmitting the rotation of the drive motor 11 decelerated by the reduction gear mechanism 12 to the rotation shaft 3 by connecting the rotation shaft 3 and the reduction gear mechanism 12. A gear 47 (FIG. 4 (a)) that meshes with the internal teeth 46 of the carrier 40 is formed inside the prism 3a provided at the upper end of the carrier 40 while preventing rotation. The joint 45 includes an operation handle 50 that is used to rotate the joint 45 when adjusting the operating angle of the rotating shaft 3 and two operating units that tilt the lever member 54 of the operating angle detection mechanism 13. 51 and 52 are provided. The operation portions 51 and 52 are configured by step portions provided in the cylindrical portion 45 </ b> A of the joint 45. The operation part 51 and the operation part 52 are provided approximately 95 degrees apart in the circumferential direction of the cylindrical part 45A.

  The operating angle detection mechanism 13 includes the lever member 54 and two limit switches 60 and 61 as rotation position detection means that are turned on and off by tilting the lever member 54. The lever member 54 is erected so as to be tiltable in the left-right direction (arrow A, B direction) of the case 30 in FIG. 4A, and neither of the operation portions 51, 52 of the joint 45 is in contact. In FIG. 4, the switch stands up substantially vertically and maintains a non-contact state with respect to any of the limit switches 60 and 61. As such a lever member 54, a lever of an automatic return type is used by pivotally supporting the lower end portion by a support shaft so as to be rotatable and attaching a weight below the support shaft.

  The limit switches 60 and 61 are similarly disposed on the case 30 so as to face each other in the vicinity of the tilting direction with the lever member 54 interposed therebetween. Further, of the two limit switches 60 and 61, the limit switch 61 located on the right side in FIG. 5A is the minimum turning position of the joint 45 shown in FIG. 5 (when the valve opening degree of the valve is 0%). When the lever member 54 is turned on, the first output is generated, and the second output is generated at the other rotation positions. At this time, the limit switch 62 located on the left side maintains the OFF state.

  The limit switch 62 located on the left side is turned on by the lever member 54 at the maximum rotation position (rotation position when the valve opening degree is 100%) shown in FIG. A maximum rotation position detecting means for generating a first output and generating a second output at other rotation positions is configured. At this time, the right limit switch 61 holds the OFF state. Note that, when the valve opening is fully closed and the intermediate opening other than fully open, the lever member 54 is not tilted by any of the operating portions 51 and 52 of the joint 45, and therefore the limit switches 60 and 61 are both in the OFF state. keeping.

Next, the operation of the electric actuator 2 having such a structure will be described.
When the drive motor 11 is driven by a drive signal from the control unit, the rotation of the output shaft 22 is decelerated by the reduction gear mechanism 12 and transmitted to the rotation shaft 3 of the ball valve 1 through the joint 45. That is, when the drive motor 11 is driven, the rotation of the output shaft 22 is transmitted to the gears 33 and 34 through the pinion 24. Further, the rotation of the gear 34 is transmitted to the sun gear 36 through the gear 35, thereby rotating the planetary gear 37. When the planetary gear 37 rotates, the sun gear 38 rotates along with the rotation of the planetary gear 37 and decelerates the rotation of the sun gear 36. Further, the rotation of the sun gear 38 is decelerated when transmitted to the planetary gear 39, and the carrier 40 rotates with the rotation of the planetary gear 39. Furthermore, since the rotation of the carrier 40 is transmitted to the joint 45 via the gears 46 and 47, the joint 45 and the rotary shaft 3 rotate together.

  When the rotating shaft 3 rotates, the operating angle detection mechanism 13 detects the operating angle of the rotating shaft 3. That is, when the valve opening degree of the ball valve 1 is 50% (the operating angle of the rotary shaft 3 = 0 °), the lever member 54 stands substantially vertically as shown in FIG. And the limit switch 61. Further, it is located in the middle of the two operation portions 51 and 52 of the joint 45. For this reason, in this state, the limit switches 60 and 61 are not in contact with the lever member 54 and are kept in the OFF state.

  When the rotating shaft 3 rotates in the closing direction from the valve opening degree of 50%, the joint 45 also rotates integrally with the rotating shaft 3. Then, when the rotary shaft 3 rotates by a predetermined angle (−45 °), one operation portion 51 of the joint 45 comes into contact with and presses the lower end portion of the lever member 54, and the lever member 54 is moved to the position shown in FIG. Tilt to the right as shown. Therefore, the lever member 54 presses the movable contact of the limit switch 60 to turn on the limit switch 60, and the output signal is sent to the control unit. When receiving the output signal from the limit switch 60, the control unit stops driving the drive motor 11. As a result, the ball valve 1 is fully closed.

  On the other hand, when the rotary shaft 3 is rotated by a predetermined angle (45 °) in the opening direction from the state where the valve opening degree is 50%, the operation portion 52 of the joint 45 presses the lever member 54 as shown in FIG. Tilt to. Therefore, the lever member 54 presses the movable contact of the limit switch 61 to turn on the limit switch 61, and the output signal is sent to the control unit. When receiving the output signal from the limit switch 61, the control unit stops the driving of the drive motor 11. Thereby, the ball valve 1 is fully opened.

  As described above, in the present invention, the rotation of the joint 45 attached to the rotating shaft 3 of the ball valve 1 is detected by the two limit switches 60 and 61 provided in the case 30. Compared to the drive actuator described in the above, the structure is simple, and it is possible to reduce parts interposed in the middle from the rotating shaft to the operating angle detecting mechanism 13, and to improve the detection accuracy and reliability of the operating angle detecting mechanism 13. it can.

  In the present invention, the member that transmits the rotation of the joint 45 to the two limit switches 60 and 61 is also used as one lever member 54, and the case 30 is housed in the reduction gear mechanism 12 and the operating angle detection mechanism. Since this is also used for mounting 13, the number of parts is reduced from this point as well.

  In the above-described embodiment, the reduction gear mechanism 12 is provided separately from the drive motor 11. However, the present invention is not limited to this, and a geared motor integrally provided with the reduction gear mechanism may be used.

  Although the electric actuator according to the present invention is applied to a ball valve, the present invention is not limited to this, and can be applied to various valves and dampers. For example, a damper for opening and closing an exhaust port of a combustion device or a duct is also applicable. Can be used.

It is sectional drawing which shows one Embodiment of the electric actuator which concerns on this invention. It is a disassembled perspective view of the main components of the actuator. (A)-(c) is the front view, top view, and right view of a case. (A)-(c) is the top view, front view, and bottom view of a joint. (A), (b) is the top view and front view which show the ON / OFF state of the limit switch when the valve opening degree is 0%. (A), (b) is the top view and front view which show the ON / OFF state of the limit switch when the valve opening degree is 50%. (A), (b) is the top view and front view which show the ON / OFF state of the limit switch when the valve opening degree is 100%.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ball valve, 2 ... Electric actuator, 3 ... Rotating shaft, 5 ... Housing, 11 ... Drive motor, 12 ... Reduction gear mechanism, 13 ... Operating angle detection mechanism, 30 ... Case, 45 ... Joint (connection member), 54 ... Lever member, 60, 61 ... Limit switch, U1, U2 ... Planetary gear unit.

Claims (3)

A drive motor disposed in the housing, a reduction gear mechanism that reduces the rotation of the drive motor and transmits the rotation to the rotation shaft, and connects the rotation shaft and the reduction gear mechanism to rotate integrally with the rotation shaft. A connecting member, and an operating angle detecting mechanism that detects an operating angle of the rotating shaft by rotating the connecting member,
An electric actuator characterized in that the operating angle detection mechanism is provided in a case that houses the reduction gear mechanism. The operating angle detection mechanism generates a first output at a maximum rotation position of the connecting member, and a maximum rotation position detection unit that generates a second output at other rotation positions;
Minimum rotation position detecting means for generating a first output at the minimum rotation position of the connecting member and generating a second output at other rotation positions;
When the connecting member is rotated to the maximum rotation position, the connecting member receives a pressing force, transmits the pressing force to the maximum rotation position detecting means, and the connecting member rotates to the minimum rotation position. 2. The electric actuator according to claim 1, further comprising a swingable lever member that sometimes receives a pressing force by the connecting member and transmits the pressing force to the minimum rotation position detecting means. 3. The electric actuator according to claim 2, wherein the maximum rotation position detection means and the minimum rotation position detection means are constituted by two limit switches facing each other with the lever member interposed therebetween.

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