WO2018216526A1

WO2018216526A1 - Electric valve actuator and valve device

Info

Publication number: WO2018216526A1
Application number: PCT/JP2018/018537
Authority: WO
Inventors: 卓志松任; 山下　洋平
Original assignee: Ntn株式会社
Priority date: 2017-05-23
Filing date: 2018-05-14
Publication date: 2018-11-29
Also published as: JP2018197566A

Abstract

Provided is an electric valve actuator that can open and close a valve with high accuracy with a compact structure. An electric valve actuator 1 is provided with: a motor 2 that receives a supply of electric power and generates a rotary driving force; a ball screw device 3; a valve shaft 4; and a motion conversion mechanism 5 that converts linear motion of a nut member 32 of the ball screw device 3 into rotational motion of the valve shaft 4. In this electric valve actuator 1, a screw shaft 31 of the ball screw device 3 is rotatably supported by a pair of bearings 33, 34, and the valve shaft 4 is disposed between the bearings 33, 34.

Description

Electric actuator for valve and valve device

The present invention relates to an electric actuator for a valve and a valve device.

As part of countermeasures against exhaust gas from internal combustion engines such as automobile engines, these internal combustion engines are mixed with intake air once again to reduce the oxygen concentration of the air in the combustion chamber and lower the combustion temperature. Therefore, exhaust gas recirculation devices (hereinafter also referred to as EGR devices) that reduce nitrogen oxides (NOx) are widely used. In this EGR device, a part of the exhaust gas exhausted is recirculated to the intake side as recirculated exhaust gas (hereinafter also referred to as EGR gas). In order to adjust the flow rate of the EGR gas, recirculated exhaust gas flow rate control is performed. A valve (hereinafter referred to as an EGR valve) is used.

In recent years, motorization has been progressing in automobiles in order to save labor and reduce fuel consumption. In response to this trend, attempts have been made to open and close valves for electric EGR devices using electric actuators. As an example, for example, the output of the motor is transmitted to the valve shaft of the EGR valve via a speed reduction mechanism comprising a gear train, and the valve shaft is driven to rotate (Patent Document 1), or the output of the motor is transmitted by a feed screw mechanism. There is known a technique that converts a linear motion into a rotational motion of a valve shaft via a link mechanism (Patent Document 2).

JP 2009-156115 A JP 2002-54512 A

However, in the drive mechanism of Patent Document 1, since the backlash of the gear train that constitutes the speed reduction mechanism is unavoidable, the opening and closing accuracy of the EGR valve is insufficient.

Since the opening / closing mechanism of the EGR valve of Patent Document 2 uses a feed screw device and does not use a speed reducer, a decrease in opening / closing accuracy due to backlash can be avoided. However, this opening / closing mechanism has a structure in which a female screw member screwed into a screw shaft is press-fitted into the inner periphery of the hollow rod, and a link mechanism is connected to the tip of the hollow rod. For this reason, a link mechanism and a valve shaft are arranged in the screw shaft and in the region on the tip side of the hollow rod (region opposite to the motor coupling side), and the size of the drive mechanism is the direction in which the screw shaft extends. It is getting bigger. Accordingly, there is a risk that the installation in the engine room where the surplus space is restricted may be hindered. Further, since the region of the hollow rod that receives the load from the valve shaft and the link mechanism is in a cantilevered state, the hollow rod or the like may be deformed due to the load load, and the accuracy of the valve opening / closing operation may be reduced. This problem is particularly a concern when the screw shaft is extended.

Therefore, an object of the present invention is to provide an electric actuator for a valve and a valve device that are compact and have high valve opening / closing accuracy.

In order to solve the above problems, the present invention includes a motor unit that generates a rotational driving force and a shaft-shaped rotating member that is rotationally driven by the motor unit, and the rotational motion of the rotating member is linearly moved. A first motion conversion mechanism unit that converts to a valve shaft, and a second motion conversion mechanism unit that converts the linear motion output from the first motion conversion mechanism unit into a rotational motion of the valve shaft. In the valve electric actuator, the rotating member is rotatably supported by a pair of bearings, and the valve shaft is disposed between the pair of bearings.

With this configuration, compared with the case where the valve shaft and the link mechanism are arranged in the tip side of the rotating member, the length of the electric actuator for the valve in the extending direction of the rotating member is shortened to achieve compactness. Can do. Moreover, the load load to a rotating member is performed between a pair of bearings spaced apart in the direction where a rotating member extends among rotating members. In this region, since the rotating member is supported at both ends by the bearing, the deformation of the rotating member is less likely to occur compared to the configuration described in Patent Document 2 in which a load is applied to the cantilevered region. Therefore, it is possible to improve the opening / closing accuracy when the valve is opened / closed.

In this valve electric actuator, the first motion conversion mechanism portion and the second motion conversion mechanism portion constitute a link mechanism, and the movement trajectory of each link of the link mechanism is arranged between the pair of bearings. preferable. With this configuration, the same operational effects as described above can be obtained.

In this case, it is preferable to provide two sliders in the link mechanism. With this configuration, the angular velocity of the valve shaft can be expressed by a relatively simple expression using a trigonometric ratio, where the moving speed V of the slider on the driving side is a constant (constant). Therefore, it is easy to design such that the angular velocity of the valve shaft near the fully closed state of the valve is reduced, while the angular velocity of the valve shaft near the intermediate state is increased. On the other hand, in the configuration of Patent Document 1 in which the output of the motor unit is transmitted to the valve shaft via a gear train, the rotational speed of the motor unit is changed if a difference is made in the angular velocity according to the open / close state of the valve. Inevitably, motor control becomes complicated.

The screw shaft is used as the rotating member of the first motion conversion mechanism, and this screw shaft is arranged in parallel with the pipe extending direction in the vicinity of the valve shaft, thereby effectively utilizing the excess space around the pipe. An electric actuator for a valve can be provided.

If the angular velocity of the valve shaft is minimized in the vicinity of the fully closed state of the valve while keeping the rotational speed of the rotating member constant, the valve opening / closing accuracy near the fully closed state of the valve can be improved. As a result, for example, when an electric actuator for a valve is used in an EGR device, the opening / closing accuracy of the valve can be increased in the vicinity of a fully closed state that is important for the function of the EGR device.

The valve electric actuator includes an input unit that is driven by the first motion conversion mechanism unit to perform a linear motion, an output unit that performs a rotational motion around the valve shaft together with the valve shaft, and an input unit and an output unit. It is preferable to include a connecting portion that is provided on any one of them, engages with the other, and allows the input portion and the output portion to be connected to each other so as to allow sliding movement relative to the other. In such a configuration, if each link is designed so that the turning radius of the connecting portion is maximized when the valve is fully closed, the angular velocity of the valve shaft near the fully closed state is reduced and the opening and closing accuracy of the valve is increased. Can do.

If a housing for accommodating the valve shaft is provided, and an elastic member that biases the valve shaft in a direction in which the valve is fully closed is disposed between the housing and the output portion of the second motion conversion mechanism, Even when an abnormality occurs in one conversion mechanism, the valve can be automatically shifted to the fully closed state, and the fail-safe function is enhanced.

By providing a sensing device that detects the degree of opening and closing of the valve from the movement of either the first motion conversion mechanism, the valve shaft, or the second motion conversion mechanism, the degree of opening and closing of the valve is detected. Can be controlled.

A valve device can be constituted by the electric actuator described above and a valve provided on the valve shaft.

According to the present invention, it is possible to provide an electric actuator for a valve and a valve device that are compact and have high valve opening / closing accuracy.

It is a perspective view of the electric actuator for valves concerning one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line XX of FIG. It is a perspective view which expands and shows a valve shaft. FIG. 2 is a cross-sectional view taken along line YY in FIG. FIG. 6 is a sectional view taken along line XX when the valve is in a fully closed state. FIG. 6 is a sectional view taken along line XX when the valve is in an intermediate state. FIG. 6 is a sectional view taken along line XX when the valve is fully opened. It is a top view of the valve apparatus concerning one embodiment of the present invention. It is a figure which simplifies and shows the link mechanism of the electric actuator for valves concerning one embodiment of the present invention. It is a figure which simplifies and shows the link mechanism of the conventional electric actuator.

Hereinafter, embodiments of an electric actuator for a valve according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an electric actuator for a valve according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line XX of FIG. FIG. 3 is an enlarged perspective view showing the valve shaft, and FIG. 4 is a cross-sectional view taken along line YY of FIG. The XX line coincides with a center line O1 of a screw shaft 31 described later, and the YY line coincides with a center line O2 of a valve shaft 4 described later.

The electric actuator 1 for valves in this embodiment is used for, for example, an EGR device of a car.
As shown in FIGS. 1 and 2, the electric actuator 1 for a valve receives a supply of electric power to generate a rotational driving force, and converts a rotational motion obtained by the motor portion 2 into a linear motion. The first motion conversion mechanism 3, the valve shaft 4, and the second motion conversion mechanism that converts the linear motion output from the first motion conversion mechanism 3 into a rotational motion around the valve shaft 4. And 5.

The motor unit 2 is composed of, for example, a radial gap type motor (for example, a three-phase brushless motor) provided with a stator and a rotor. As shown in FIG. 2, the output shaft 21 of the motor unit 2 has a solid shape, and both axial ends thereof are a bearing 23 fixed to the inner peripheral surface of the motor housing 22 and a bearing (not shown) disposed inside the motor. It is supported rotatably. Reference numeral 25 denotes a terminal portion that accommodates a bus bar, a substrate, etc. (not shown).

The first motion conversion mechanism unit 3 of the present embodiment is composed of a ball screw device. The ball screw device 3 includes a screw shaft 31 as a shaft-like rotating member, and a nut member 32 fitted to the outer periphery of the screw shaft 31 via a plurality of balls. The screw shaft 31 is arranged coaxially with the output shaft 21 of the motor unit 2, and its base end (end on the motor unit 3 side) is directly connected to the output shaft 21 of the motor unit 2 without interposing a reduction gear or the like. Are combined. Ends on both axial sides of the screw shaft 31 are rotatably supported with respect to the housing (valve housing 42) by

bearings

33 and 34 such as rolling bearings, respectively. With this configuration, when the motor unit 2 is driven in the forward / reverse direction, the screw shaft 31 rotates in the forward / reverse direction.

A plurality of balls are incorporated between the spiral groove formed on the outer peripheral surface of the screw shaft and the spiral groove formed on the inner peripheral surface of the nut member 32. By rotating the screw shaft 31, the nut member 32 performs a linear motion along the direction in which the screw shaft 31 extends, and the ball circulates between both spiral grooves. The circulation of the ball can be performed by providing a top (not shown) as a circulation member on the nut member 32, for example.

The second motion conversion mechanism unit 5 includes an input unit 51, an output unit 52, and a connection unit 53 that connects the input unit 51 and the output unit 52.

The input part 51 is a cylindrical member, and is fixed to the outer peripheral surface of the nut member 32 by means such as press fitting. Therefore, the input part 51 extends the screw shaft 31 in conjunction with the linear motion of the nut member 32. Make a linear motion in the direction. The input portion 51 is formed with a through hole that is separated from the center line O1 of the screw shaft 31 and extends in a direction orthogonal to the screw shaft 31. A pin having a cylindrical outer peripheral surface as the connecting portion 53 is formed in the through hole. Is press-fitted and fixed. One end of the pin 53 protrudes toward the output unit 52 from the end surface of the input unit 51 (see FIG. 4).

As shown in FIG. 3, the output portion 52 of the present embodiment is formed integrally with the valve shaft 4 at one end portion (end portion on the screw shaft 31 side) of the valve shaft 4 and extends in the radial direction of the valve shaft 4. It has a flat form. A groove portion 52a is formed in the output portion 52 along the radial direction of the valve shaft 4, and a pin 53 is fitted in the groove portion 52a to allow sliding movement in the extending direction of the groove portion 52a (FIG. 5A). To FIG. 5C). In the present embodiment, one end of the groove part 52a is opened at the tip of the output part 52, but it may be closed without opening one end of the groove part 52a. Further, a locking portion 52 b for locking an end portion 44 b of a torsion coil spring 44 described later is provided at the tip of the output portion 52. Although the case where the output portion 52 is provided integrally with the valve shaft 4 is illustrated, the output portion 52 and the valve shaft 4 may be separate parts, and the output portion 52 may be fixed to the valve shaft 4 by means such as press fitting. .

A slit 4b is formed in the main body of the valve shaft 4 along the direction in which the valve shaft 4 extends. A disc-shaped valve 41 (butterfly valve) is inserted into the slit 4b. The valve 41 is fixed to the valve shaft 4 by screwing a screw or the like into a screw hole 4 c provided in the main body of the valve shaft 4.

As shown in FIG. 4, the valve shaft 4 is rotatably supported by a bearing 43 fixed to the valve housing 42. As the bearing 43, in this embodiment, for example, a case where two rolling bearings 43 are arranged in a state where the inner rings and the outer rings are in contact with each other is illustrated. Each outer ring of the rolling bearing 43 is provided with a seal member 45 and a retaining ring 46 attached to the valve housing 42, and each inner ring of the rolling

bearings

42 and 43 is provided with a shoulder 4 a of the valve shaft 4 and a retaining ring 47 attached to the valve shaft 4. Are positioned in the axial direction of the valve shaft 4 respectively.

As shown in FIG. 4, a return spring 44 is disposed as an elastic member on the outer periphery of the rolling

bearings

42 and 43. In this embodiment, the case where the torsion coil spring 44 is used as a return spring is illustrated. As shown in FIG. 2, one end 44a of the torsion coil spring 44 is attached to the valve housing 42, and the other end 44b is locked to a locking portion 52b provided at the tip of the output portion 52 (see FIG. 5A). The torsion coil spring 44 constantly biases the valve shaft 4 in the direction in which the valve 41 is fully closed (counterclockwise in FIG. 5A). When the valve 41 is in the fully closed state, the valve 41 receives a rotational moment due to the pressure of the exhaust gas flowing through the piping, but is twisted so that the valve 41 is maintained in the fully closed state against the pressure of the exhaust gas. The elastic force of the coil spring 44 is set.

FIG. 6 is a plan view of the valve device.
In the valve electric actuator 1 shown in FIG. 1, as shown in FIG. 6, the valve electric actuator 1 and the valve 41 are formed by covering an opening formed between the motor housing 22 and the valve housing 42 with a valve cover 60. Is completed. The motor housing 22, the valve housing 42 and the valve cover 60 function as a housing for the valve electric actuator 1 as a whole. The division mode and the number of divisions of the housing are not limited to the above example, and can be arbitrarily adopted.

As shown in FIG. 6, the completed valve device is disposed in the engine room of the automobile, and the exhaust passage pipe 49 (shown by a two-dot chain line) is provided at both end openings 42 a (see FIG. 1) of the valve housing 42. Is attached. At this time, the valve electric actuator 1 is attached so that the center line O1 (XX line in FIG. 6) of the screw shaft 31 is parallel to the extending direction of the pipe 49 in the vicinity of the valve shaft 4. Correspondingly, the center line O2 (YY line in FIG. 6) of the valve shaft 4 has a shape extending in a direction orthogonal to the extending direction of the pipe 49.

Hereinafter, the operation of the electric actuator for valves 1 described above will be described with reference to FIGS. 5A to 5C. 5A to 5C are illustrations in which the motor unit 2 and the first motion conversion mechanism unit 3 are not shown in the cross-sectional view shown in FIG.

FIG. 5A shows a fully closed state of the valve 41 (see FIG. 1). In the fully closed state, the connecting portion 53 of the second motion conversion mechanism 5 is located at the outer diameter end of the groove portion 52a, and the distance (rotation radius) from the center O2 of the valve shaft 4 is maximum. From this state, when the motor unit 2 is driven in the forward direction, the screw shaft 31 rotates and the nut member 32 and the input unit 51 are in the direction of the screw shaft 31 and away from the motor unit 2 (left direction in FIG. 2). ) To slide. Along with this, the output portion 52 engaged with the connecting portion 53 in the rotation direction rotates in the clockwise direction (forward rotation) in FIG. 5A, and this rotation is transmitted to the valve shaft 4, thereby opening the valve 41. start. As the output unit 52 rotates in the positive direction, elastic force is accumulated in the torsion coil spring 44. While the output portion 52 is rotating in the forward direction, the connecting portion 53 is guided by the groove portion 52a of the output portion 52 and slides in the inner diameter direction of the valve shaft 4 while rotating relative to the groove portion 52a. Along with this, the rotation radius of the connecting portion 53 gradually decreases.

When the output portion 52 is further rotated in the forward direction, as shown in FIG. 5B, the connecting portion 53 reaches the inner diameter end of the groove portion 52a, the rotation radius thereof is minimized (intermediate state), and then the connecting portion 53 is connected to the valve shaft. 4 reversely moves toward the outer diameter direction. Eventually, the valve 41 shown in FIG. 5C is in a fully opened state (a state rotated by 90 ° from the fully closed state). In this fully opened state, the connecting portion 53 is in the groove 52a as in the fully closed state. Located at the outer diameter end, the turning radius is maximum.

When the motor unit 2 is driven in the reverse direction, the operation opposite to the above operation is performed, the output unit 52 rotates counterclockwise (reverse rotation), and the valve 41 is closed. Depending on the driving state of the vehicle and the like, the motor unit 2 is driven forward / reversely to control the opening / closing of the valve 41 so that optimum exhaust gas recirculation is performed.

In the process of opening the valve 41, the elastic force is accumulated in the torsion coil spring 44 as described above. When the motor unit 2 becomes uncontrollable due to some abnormality, the valve 41 is automatically switched to the fully closed state by this elastic force. Thus, the torsion coil spring 44 basically functions as a fail safe when the motor is abnormal. Therefore, the valve 41 is normally opened and closed by forward and reverse driving of the motor unit 2. Note that when the transition from the fully open state to the fully closed state is performed, the elastic force accumulated in the torsion coil spring 44 is superimposed on the driving force of the motor unit. Thus, the power consumption of the motor unit 2 is reduced.

In the valve electric actuator 1 described above, in order to control the open / close state of the valve 41, it is preferable to arrange a sensing device for detecting the degree of valve opening / closing inside the valve electric actuator 1. As an example of this sensing device, for example, as shown in FIG. 4, a stroke sensor 61 is attached to the inner surface of the valve cover 60, and a magnet 62 is attached to the input unit 51 of the second motion conversion mechanism 5 so as to face this. It is possible to wear it. If the stroke sensor 61 is used in this manner, the position of the input portion 51 in the direction of the screw shaft 31 can be detected, and the open / closed state of the valve 41 can be recognized from the detected value. The configuration of the sensing device is arbitrary as long as the degree of opening and closing of the valve 41 can be detected. In addition to detecting the position of the input unit 51 using the stroke sensor 61 as described above, the output unit 52 using a rotation angle sensor. It is also possible to directly detect the rotation phase. Further, the rotational phase of the motor unit 2 and the screw shaft 31 may be detected, or the movement amount of the nut member 32 may be detected. As described above, the sensing device is configured to open and close the valve 41 from any movement (linear movement or rotational movement, or both) of the first movement conversion mechanism section 3, the second conversion mechanism section 5, or the valve shaft 4. It is set as the structure which detects.

In the electric actuator 1 for a valve according to the present embodiment, the valve shaft 4 is disposed between a pair of

bearings

33 and 34 that support the screw shaft 31 as shown in FIGS. Further, the movement trajectories of the input portion 51, the output portion 52, and the nut member 32 accompanying the opening and closing of the valve 41 are all in the region between the pair of

bearings

33 and 34. Therefore, the length in the direction of the screw shaft 31 of the valve electric actuator 1 can be shortened as compared with the configuration in which the valve shaft and the link mechanism are arranged in the region closer to the screw shaft tip side than the screw shaft as in Patent Document 2. The area where the exhaust gas recirculation flow path can be installed in the engine room is limited. On the other hand, there is a certain gap between the pipe 49 of the flow path and the peripheral device to prevent thermal effects. It is customary to provide it. Therefore, by shortening the length of the electric actuator 1 for the valve in the direction of the screw shaft 31 as in the present embodiment, the valve device is installed in the engine room even if the thickness in the direction of the valve shaft 4 slightly increases. It becomes easy.

In addition, the load applied to the screw shaft 31 is performed in a region between the pair of

bearings

33 and 34 in the screw shaft 31. Since the screw shaft 31 is supported at both ends by the

bearings

33 and 34 in this region, the deformation of the screw shaft 31 is less than that of the configuration of Patent Document 2 in which a load is applied to the cantilevered region of the hollow rod. It becomes difficult to occur. Therefore, it is possible to improve the opening / closing accuracy and stability when the valve is opened / closed.

In addition, since a ball screw device is used as the first motion conversion mechanism 3, the efficiency is higher than that in the case of using a feed screw device in which friction between the female screw member and the screw shaft is increased as in Patent Document 2. Can be achieved. Therefore, the capacity of the motor unit can be reduced. Further, when using a feed screw device as in Patent Document 2, it is necessary to increase the elastic force of the return spring that shifts the valve to the fully closed state during fail-safe handling in response to motor abnormality, as in this embodiment. If a ball screw device is used, the size of the return spring (torsion coil spring 44) can be reduced because of its high efficiency. Therefore, the size can be reduced as compared with the electric actuator described in Patent Document 2.

In this embodiment, the torsion coil spring 44 as a return spring is disposed between the housing (valve housing 42) that accommodates the valve shaft 4 and the output portion 52. That is, the torsion coil spring 44 is disposed downstream of the ball screw device 3 in the motor driving force transmission path. Therefore, even if some abnormality occurs in the ball screw device 3, the valve 41 can be automatically returned to the fully closed state, and the fail-safe function can be further improved.

Incidentally, in the EGR device, due to the characteristics of the EGR device, it is necessary to control the opening / closing amount of the valve 41 more severely in the vicinity of the fully closed state than in the intermediate state of the valve 41 (the state of FIG. 5B). This is because the amount of recirculated EGR gas is generally small. In the present embodiment, as described above, the rotation radius of the connecting portion 53 is maximized when the valve is fully closed (see FIG. 5A). In this state, even if the sliding speed of the input portion 51 is constant, FIG. The angular speed of the output unit 52, that is, the opening / closing speed of the valve 41 is minimized compared to the intermediate state shown in FIG. Therefore, the valve 41 can be accurately controlled in the vicinity of the fully closed state, and the valve opening / closing characteristics required for the EGR device are met.

FIG. 7A shows a simplified link mechanism including the first motion conversion mechanism 3 and the second motion conversion mechanism 5 described above. Thus, the 1st motion conversion mechanism 3 and the 2nd motion conversion mechanism 5 comprise the link mechanism which has two sliders S1 and S2. Of the two sliders S <b> 1 and S <b> 2, the first slider S <b> 1 is configured by the nut member 32 (or the input unit 51), and the second slider S <b> 2 is configured by the connecting unit 53. If the link mechanism has two sliders as described above, the angular velocity of the valve shaft 4 (angular velocity of the output unit 52) is a comparison using a trigonometric ratio with the moving velocity V of the first slider S1 as a constant (constant). Can be expressed by a simple formula. Therefore, it is possible to easily design the valve shaft 4 near the fully closed state while reducing the angular velocity of the valve shaft 4 while increasing the angular velocity of the valve shaft 4 near the intermediate state, thereby improving the performance of the EGR device. Such an effect can be obtained by using another link mechanism as long as the link mechanism has two sliders. For example, the same effect can be obtained by a mechanism (both reciprocating slider crank mechanism) in which the connecting portion 53 is provided in the output portion 52 and the connecting portion 53 is slidably fitted in the groove portion 52a provided in the input portion 51. Can be obtained.

On the other hand, in the configuration in which the output of the motor unit is transmitted to the valve shaft via the reduction gear as in Patent Document 1, if the difference in the angular velocity of the valve shaft is set according to the open / close state of the valve, the motor The rotation speed of the part must be changed, and the control of the motor becomes complicated.

Further, the link mechanism described in Patent Document 2 is a so-called reciprocating slider crank mechanism in which only one of the four links 81 to 84 is a slider S3 (female screw member 82) as shown in FIG. 7B. In this link mechanism, the equation for obtaining the angular velocity of the valve shaft (angular velocity of the link 84) is complicated, and even if simplified, only an approximate equation can be obtained. Therefore, a design for reducing the angular velocity of the valve shaft 4 near the fully closed state while increasing the angular velocity of the valve shaft 4 in the intermediate state cannot be easily realized. The opening / closing accuracy of the valve 41 near the fully closed state is inferior.

In the above description, the EGR device is illustrated as an application of the electric actuator for the valve. However, the electric actuator for the valve according to the present invention is not limited to the EGR device, but can be used to open and close valves mounted on other in-vehicle devices and industrial devices. Can be widely used for In addition, the butterfly valve is exemplified as a valve that is opened and closed by the electric actuator for the valve, but the applicable valve type is not limited to the butterfly valve, as long as the valve opening and closing amount is controlled by forward and reverse rotation of the valve shaft, The electric actuator for valves of the present invention can be used for other valve devices (for example, ball valves).

1 Electric Actuator 2 Motor Unit 3 First Motion Conversion Mechanism (Ball Screw Device)
4 Valve shaft 5 Second motion conversion mechanism 22 Housing (motor housing)
31 Rotating member (screw shaft)
32 Nut member 33 Bearing (Rolling bearing)
34 Bearing (Rolling bearing)
41 Valve 42 Housing (Valve Housing)
44 Elastic member (screw recoil spring)
49 Piping 51 Input Portion 52 Output Portion 53 Connecting Portion O1 Screw Shaft Centerline O2 Valve Shaft Centerline S1 First Slider S2 Second Slider

Claims

A motor unit that generates a rotational driving force; a shaft-shaped rotating member that is rotationally driven by the motor unit; a first motion conversion mechanism unit that converts a rotational motion of the rotating member into a linear motion; and a valve shaft; In the valve electric actuator comprising: a linear motion output from the first motion conversion mechanism portion; and a second motion conversion mechanism portion for converting the linear motion into a rotational motion of the valve shaft.
An electric actuator for a valve, wherein the rotary member is rotatably supported by a pair of bearings, and the valve shaft is disposed between the pair of bearings.
The valve electric motor according to claim 1, wherein a link mechanism is configured by the first motion conversion mechanism section and the second motion conversion mechanism section, and a movement locus of each link of the link mechanism is disposed between the pair of bearings. Actuator.
The electric actuator for a valve according to claim 2, wherein the link mechanism includes two sliders.
4. The screw shaft according to claim 1, further comprising a screw shaft as a rotating member of the first motion conversion mechanism section, wherein the screw shaft is arranged in parallel with a pipe extending direction in the vicinity of the valve shaft. Electric actuator for valves.
The electric actuator for a valve according to any one of claims 1 to 4, wherein the angular velocity of the valve shaft is minimized in the vicinity of the fully closed state of the valve while the rotational speed of the rotating member is constant.
An input unit that is driven by the first motion conversion mechanism unit to perform a linear motion, an output unit that performs a rotational motion about the valve shaft, and an input unit or an output unit together with the valve shaft. The valve electric motor according to any one of claims 1 to 5, further comprising a connecting portion that engages with the other and rotatably connects the input portion and the output portion while allowing sliding movement with respect to the other. Actuator.
A housing that houses the valve shaft, and an elastic member that urges the valve shaft in a direction in which the valve is fully closed is disposed between the housing and the output portion of the second motion conversion mechanism. Item 7. The electric actuator for a valve according to Item 6.
The sensing device according to any one of claims 1 to 7, further comprising: a sensing device that detects a degree of opening and closing of the valve from the movement of any one of the first motion conversion mechanism unit, the valve shaft, and the second motion conversion mechanism unit. Actuator for valves.
A valve device comprising the electric actuator for a valve according to any one of claims 1 to 8, and a valve provided on the valve shaft.