JP3485837B2 - Actuator and rotation amount detection device usable therefor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator which can be suitably used for controlling the opening of a valve such as a ball valve or a butterfly valve, and a rotation amount detecting device which can be suitably used in the actuator.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a conventional actuator disclosed in Japanese Patent Publication No. 5-71821. In the figure, 1 is a housing, 3 is an output shaft member rotatably held in the housing 1, 4 is a drive motor for generating rotational driving force, 5 is a base plate to which the drive motor 4 is fixed, and 6 is a drive motor. A drive transmission gear group for transmitting the rotational drive force of 4 to the output shaft member 3, 8 is a potentiometer including a rotor 8a and a stator 8b, 19 is a fixed base for fixing the stator 8b of the potentiometer 8 to the base plate 5, and 20 is an output shaft. It is a rotation detection gear group that transmits the rotation of the member 3 to the rotor 8a.

Next, the operation will be described. Drive motor 4
When is rotated, the drive transmission gear group 6 transmits this rotational movement to the output shaft member 3, and the output shaft member 3 is thereby rotated. Therefore, the valve shaft of the valve fixed to the output shaft member 3 also rotates by a predetermined amount, and the valve is opened and closed at a predetermined opening degree according to the rotation amount.

Since the rotation detection gear group 20 transmits the rotation of the output shaft member 3 to the rotor 8a of the potentiometer along with the opening / closing operation of the valve, the attitude of the rotor 8a of the potentiometer with respect to the stator 8b changes. A rotation amount detection signal corresponding to this is output. The rotation amount detection signal is used to detect the opening of the valve in a control circuit that controls the drive motor 4.

[0005]

Since the conventional actuator is constructed as described above, when the output shaft member 3 is touched in the direction perpendicular to its rotation axis, the output of the potentiometer 8 changes. This is one factor that determines the upper limit of the detection accuracy of the rotation amount.

A detailed description will be given with reference to FIG. FIG. 1A shows the output shaft member 3 and the rotor 8 of the potentiometer 8.
The top view in the case of a normal positional relationship with a, the same figure (b)
FIG. 6 is a top view when the output shaft member 3 and the rotor 8a of the potentiometer 8 are displaced from each other. Then, as shown in the figure, since the output shaft member 3 and the rotor 8a are connected by the rotation detection gear group 20, when the output shaft member 3 is shaken and moved, the rotor 8a also rotates accordingly. Therefore, the potentiometer 8 will detect the movement of the output shaft member 3 as the rotation operation of the output shaft member 3. Therefore, it is impossible to obtain the detection accuracy higher than the erroneous rotation detection amount due to the blur. For example, when an inexpensive oil-impregnated sintered bearing is used as a bearing for supporting the output shaft member 3, such a blur is apt to occur, and in order to solve this, a high precision bearing is used. It was also necessary to improve the processing accuracy and assembly accuracy of parts.

The present invention has been made to solve the above problems. Even if the output shaft member touches the direction perpendicular to its rotation axis, the output of the rotation detector changes due to the touching. Which can be used for an actuator that can improve the detection accuracy of the rotation amount by suppressing the rotation amount, and thus can use the potentiometer in the actuator for a fuel control valve that requires high accuracy. The purpose is to obtain the device.

[0008]

A rotation amount detecting device according to the present invention is a rotation amount detecting device for detecting a rotation amount of a rotating member rotating in a housing, wherein the rotating member is provided around the same rotation axis with respect to the rotating member. A rotor that is fixed so as to rotate, and a rotation detector that has a stator that outputs a rotation amount detection signal according to the rotation amount of the rotor, and the stator that moves in a direction perpendicular to the rotation axis of the rotating member. And a holding member which holds the housing on the housing so as to be swingable.

An actuator according to the present invention includes a housing, an output shaft member rotatably arranged with respect to the housing, a rotation driving means for rotationally driving the output shaft member, and the output shaft member. A rotor fixed to rotate around the same rotation axis, a rotation detector having a stator that outputs a rotation amount detection signal corresponding to the rotation amount of the rotor, and the stator, which rotates the output shaft member. And a holding member that swingably holds the housing on the housing in accordance with a deflection in a direction perpendicular to the axis.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a top view and a partially cutaway sectional view showing an internal structure of an actuator for a fuel control valve according to a first embodiment of the present invention. In the figure, 1 is a housing, 2 is a storage recess formed in the housing 1,
Reference numeral 3 denotes an output shaft member (rotating member) which is disposed so as to penetrate the bottom surface of the storage recess 2 and is rotatably held in the housing 1. Reference numeral 4 denotes a drive motor (rotation driving means) which generates a rotational driving force. Reference numeral 5 denotes a base plate which is formed at a height through which the output shaft member 3 penetrates in the middle stage of the storage recess 2 and to which the drive motor 4 is fixed, and 6 includes a gear which transmits the rotation of the drive motor 4 to the output shaft member 3. And a drive transmission gear group (rotational drive means). The output shaft member 3 is fixed to a valve shaft of a valve (not shown), and the opening degree of the valve is set according to the rotation amount of the output shaft member 3.

Reference numeral 7 denotes a joint member fixed to the end of the output shaft member 3 inside the storage recess 2, and 8 denotes the joint member 7.
The rotor 8a is fixed to the rotor 8a, and a potentiometer (rotation detector) that outputs a rotation amount detection signal corresponding to the contact position of the rotor 8a with the stator 8b. A printed circuit board 10 is mounted between the floating board 9 and the base plate 5, and a control circuit for controlling the rotational drive of the output shaft member 3 based on the rotation amount detection signal is mounted. A first link arm (holding member) and a second link arm (holding member) of the same length, one ends of which are fixed to the housing 1 so that they can rotate around axes parallel to the rotation axis of the output shaft member, respectively.
3 is an interval for holding the other end of the first link arm 11 and the other end of the second link arm 12 at the same interval as the interval between the fixed ends of the first link arm 11 and the second link arm 12. One end of each of the holding arms (holding members), 14 and 15 is rotatably fixed to the other end of the first link arm 11 and the other end of the second link arm 12, and the other end is rotatably attached to the floating substrate 9. The third link arm (holding member) and the fourth link arm (holding member) having the same length and fixed.

The distance between the other end of the third link arm 14 and the other end of the fourth link arm 15 is set to be the same as the distance between the fixed ends of the first link arm 11 and the second link arm 12. ing. In addition, the first link arm 11
Of the third link arm 14 and the length of the second link arm 12 and the fourth link arm 1
5 is set to be longer than the distance from the axis connecting the one end of the first link arm 11 and the one end of the second link arm 12 to the rotation center of the output shaft member 3. As shown in the figure, usually the first link arm 1
The inner angle between 1 and the third link arm 14 is set to be smaller than 180 °, and the inner angle between the second link arm 12 and the fourth link arm 15 is set to be smaller than 180 °. Also, these links are collectively called parallel links.

Next, the operation will be described. When the drive motor 4 rotates based on the rotation command from the control circuit mounted on the printed circuit board 10, the drive transmission gear group 6 transmits this rotation operation to the output shaft member 3, which causes the output shaft member 3 to rotate. To do. Therefore, the valve shaft of the valve fixed to the output shaft member 3 also rotates by a predetermined amount, and the valve is opened / closed at a predetermined opening degree according to the rotation amount.

Since the rotor 8a of the potentiometer 8 is fixed to the output shaft member 3 through the joint member 7 with the opening / closing operation of the valve,
The rotor 8a also rotates, and a rotation amount detection signal corresponding to the rotation amount of the rotor 8a is output from the stator 8b. This rotation amount detection signal is used in the control circuit or the like to detect the opening degree of the valve.

FIG. 2 is a perspective view of an essential part for explaining the operation in the case where the output shaft member 3 of the actuator according to the first embodiment of the present invention is touched in the direction perpendicular to its rotation axis. It should be noted that in the following, the runout of the output shaft member 3 is changed to the X-axis perpendicular to the longitudinal direction of the spacing arm 13.
Direction component and Y parallel to the longitudinal direction of the spacing arm 13
The explanation will be given separately for directionality.

First, the output shaft member 3 is the first link arm 1.
1 and the second link arm 12 when touched in the X direction so as to approach the first link arm 11 and the third link arm 1.
4, and since the second link arm 12 and the fourth link arm 15 are rotatably fixed to each other, the links are bent so that their internal angles become smaller, which causes the floating substrate 9 to move in the X-axis direction. Moving. At this time, since the floating board 9 is fixed to the housing 1 by two sets of parallel link arms having the same length, it does not rotate around the rotation center of the output shaft member 3. , Can maintain a constant posture.

Further, the output shaft member 3 is the first link arm 1
When touched in the X direction so as to move away from the first link arm 12 and the second link arm 12, the inner angles of the first link arm 11 and the third link arm 14, and the second link arm 12 and the fourth link arm 15 are large. The link is straightened so that the floating substrate 9 moves in the X-axis direction. At this time, the floating substrate 9
Is fixed to the housing 1 by two sets of parallel link arms having the same length, it is possible to maintain a constant posture without rotating around the rotation center of the output shaft member 3. it can.

Next, when the output shaft member 3 is touched in the Y direction, the spacing holding arm 13 moves in the same direction as that of the output shaft member 3, and the inner angles of the first link arm 11 and the third link arm 14 and the The link is straight or bent so that the internal angle between the second link arm 12 and the fourth link arm 15 is large or small. As a result, the floating substrate 9 moves in the Y-axis direction. And at this time,
Since the floating board 9 is fixed to the housing 1 by two sets of parallel link arms having the same length and the space between them is held by the space holding arm 13, the center of rotation of the output shaft member 3 is It is possible to maintain a constant posture without rotating around.

As described above, in the first embodiment, when the output shaft member 3 of the actuator touches the direction perpendicular to the rotation axis, the parallel link bends or straightens in accordance with the touch. Therefore, the floating substrate 9 can move in the wobbling direction while being held so as not to rotate around the output shaft member 3. Therefore, regardless of this fluctuation, the output shaft member 3 of the floating substrate 9
Since the posture with respect to is maintained constant, the stator 8b of the potentiometer 8 does not rotate with respect to the rotor 8a, and the rotation amount detection signal does not change.

As a result, it is possible to suppress the change in the rotation amount detection signal due to this shake, and the upper limit of the rotation amount detection accuracy can be improved correspondingly. Therefore, even if the potentiometer 8 is used, it is high. There is an effect that it can be used as an actuator for air fuel consumption control (particularly for fuel control) of a combustion device that requires precise opening control.

Further, even if the rattling between the housing 1 and the output shaft member 3 becomes large over time and this runout becomes large, the posture of the floating substrate 9 with respect to the output shaft member 3 is maintained constant. Therefore, it is possible to suppress deterioration of the detection accuracy with time while using the potentiometer 8, and it is possible to obtain stable and high detection accuracy with time. Therefore, the potentiometer 8 can be used by the rotation detector support mechanism in the actuator for the fuel control valve that requires high accuracy.

Embodiment 2. 3 is a top view and a partially cutaway sectional view showing an internal structure of an actuator for a fuel control valve according to a second embodiment of the present invention. In the figure, 16 is formed in an L shape, an elongated notch is formed at one end thereof, and an L-shaped link arm (holding member) to which the stator 8b of the potentiometer 8 is fixed at the other end,
Reference numeral 17 denotes a fixing screw (holding member) for fixing the L-shaped link arm 16 to the housing 1 so as to be rotatable about an axis parallel to the rotation axis of the output shaft member 3 at the long cutout portion. The other configurations are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted. The control operation of the fuel control valve is also the same as that of the first embodiment, and the description is omitted.

FIG. 4 is a perspective view of an essential part for explaining the operation in the case where the output shaft member 3 of the actuator according to the second embodiment of the present invention touches the direction perpendicular to the rotation axis. In the following description, the runout of the output shaft member 3 will be described in terms of the X-direction component perpendicular to the tangential direction of the rotation direction of the L-shaped link arm 16 and the Y-direction parallel to the tangential direction of the rotation direction of the L-shaped link arm 16. The components will be described separately.

First, when the output shaft member 3 is touched in the X direction, the L-shaped link arm 16 follows the L-shaped link arm 16 in the same direction because a long notch is formed at one end of the L-shaped link arm 16. Therefore, the stator 8b of the potentiometer 8
Does not rotate around the rotation center of the output shaft member 3 and can maintain a constant posture.

Next, when the output shaft member 3 is touched in the Y direction, the L-shaped link arm 16 rotates about the long cutout portion in the same direction. As a result, the potentiometer 8 moves in the Y-axis direction. At this time, since the stator 8b of the potentiometer 8 moves on a circle centered on one end of the L-shaped link arm 16, the stator 8b rotates around the rotation center of the output shaft member 3 depending on the amount of movement. However, the distance between the one end and the other end of the L-shaped link arm 16 can be made larger than that in the case where the output shaft member 3 is meshed with the output shaft member 3 through a gear as in the conventional case. The rotation amount of the stator 8b according to the movement amount is reduced. The longer the length of the L-shaped link arm 16, the greater the effect of reducing the rotation amount.

The following Table 1 is a table for comparing the rotation amount due to the shake according to the second embodiment of the present invention with the rotation amount due to the shake when the rotation amount is detected through the conventional gear. Specifically, the table shows an error that occurs when the output shaft member 3 moves by 1 mm. The left column shows the conventional characteristic values, and the right column shows the characteristic values in the second embodiment.

Then, as shown in the table, when the output shaft member 3 moves 1 mm in the middle of the opening / closing operation, the linearity of the opening / closing operation is ± 0.7% in the conventional case. ．
It has been improved to 4%. The backlash (hysteresis) is also improved from ± 1.0% to ± 0.3%. The table is a comparison between theoretical values when there is no play between the L-shaped link arm 16 and the fixing screw 17. Also, it was confirmed by actual measurement that the linearity of the opening / closing operation was reduced to half and the backlash was improved to about 1/3.

[0028]

[Table 1]

As described above, according to the second embodiment, when the output shaft member 3 of the actuator touches the direction perpendicular to the rotation axis of the actuator, the housing is provided with a long cutout portion according to the touch. Since the L-shaped link arm 16 rotatably and movably disposed at 1 moves or rotates, the amount of rotation of the stator 8b of the potentiometer 8 around the output shaft member 3 is reduced. Therefore, the attitude of the stator 8b with respect to the output shaft member 3 is maintained substantially constant irrespective of this fluctuation, so that the stator 8b of the potentiometer 8 hardly rotates with respect to the rotor 8a, and the rotation amount detection signal is not generated. It doesn't change much.

As a result, it is possible to suppress the change in the rotation amount detection signal due to this shake, and the upper limit of the rotation amount detection accuracy can be improved correspondingly. Therefore, there are fewer parts than the first embodiment. The potentiometer 8 can be used as an actuator for air-fuel efficiency control (particularly for fuel control) of a combustion device that requires highly accurate opening control while using the potentiometer 8 with a number of points and a simple configuration.

Further, even if the rattling between the housing 1 and the output shaft member 3 becomes large over time and this runout becomes large, the attitude of the stator 8b of the potentiometer 8 with respect to the output shaft member 3 is substantially constant. Therefore, it is possible to suppress deterioration of the detection accuracy with time while using the potentiometer 8, and it is possible to obtain stable and high detection accuracy with time. Therefore, the potentiometer 8 can be used by the rotation detector support mechanism in the actuator for the fuel control valve that requires high accuracy.

Embodiment 3. 5 is a top view and a partially cutaway sectional view showing the internal structure of an actuator for a fuel control valve according to a third embodiment of the present invention. In the figure, 18 is an elastic spacer (holding member) made of four rubbers or hard sponges disposed between the four corners of the floating board 9 and the printed board 10. The other configuration is the same as that of the first embodiment, and the same reference numerals are given to omit the description. The control operation of the fuel control valve is also the same as that of the first embodiment, and the description is omitted.

FIG. 6 is a perspective view of an essential part for explaining the operation in the case where the output shaft member 3 of the actuator according to the third embodiment of the present invention touches the direction perpendicular to the rotation axis. When the output shaft member 3 is shaken, all the elastic spacers 18 are elastically deformed by the shake force, and the floating substrate 9 moves according to the shake of the output shaft member 3. At this time, the four elastic spacers 18 are arranged in a dispersed manner around the output shaft member 3 and are elastically deformed in substantially the same direction by substantially the same force, so that the floating substrate 9 outputs. It does not rotate around the rotation center of the shaft member 3 and can maintain a substantially constant posture.

As described above, in the third embodiment, when the output shaft member 3 of the actuator touches in the direction perpendicular to the rotation axis, the elastic spacer 18 deforms and floats in response to the touch. Since the substrate 9 moves following it, the amount of rotation of the stator 8b of the potentiometer 8 around the output shaft member 3 is reduced. Therefore,
Regardless of this fluctuation, the posture of the floating substrate 9 with respect to the output shaft member 3 is maintained substantially constant, so that the stator 8b of the potentiometer 8 rarely rotates with respect to the rotor 8a, and the rotation amount detection signal is also generated. It doesn't change much.

As a result, it is possible to suppress the change in the rotation amount detection signal due to this shake, and the upper limit of the rotation amount detection accuracy can be improved correspondingly, so that there are fewer components than the first embodiment. The potentiometer 8 can be used as an actuator for air-fuel efficiency control (particularly for fuel control) of a combustion device that requires highly accurate opening control while using the potentiometer 8 with a number of points and a simple configuration.

Further, even if the rattling between the housing 1 and the output shaft member 3 increases over time and this runout increases, the attitude of the stator 8b of the potentiometer 8 with respect to the output shaft member 3 is substantially constant. Therefore, it is possible to suppress deterioration of the detection accuracy with time while using the potentiometer 8, and it is possible to obtain stable and high detection accuracy with time. Therefore, the potentiometer 8 can be used by the rotation detector support mechanism in the actuator for the fuel control valve that requires high accuracy.

In the above embodiments, the example in which the rotation amount detecting device of the present invention is applied to the actuator for the fuel control valve has been described, but the invention can also be applied to an actuator used for a butterfly valve or the like. Also,
Although the example using the potentiometer 8 has been described, even if the potentiometer 8 is an optical type, the accuracy can be similarly improved as long as the relative positional relationship similarly poses a problem.

[0038]

As described above, according to the present invention, in the rotation amount detecting device for detecting the rotation amount of the rotating member rotating in the housing, the rotating member is rotated about the same rotation axis with respect to the rotating member. A rotation detector having a rotor fixed to the rotor and a stator that outputs a rotation amount detection signal according to the rotation amount of the rotor; and the stator, which is driven by a runout of the rotating member in a direction perpendicular to the rotation axis. And a holding member that swingably holds the housing on the housing. Therefore, the holding member absorbs the runout of the rotating member in the direction perpendicular to the rotation axis, and the change in the posture of the stator around the rotation axis is suppressed accordingly. can do.

As a result, the rotation of the stator with respect to the rotor due to the runout of the rotating member in the direction perpendicular to the rotation axis can be suppressed, so that the change of the rotation amount detection signal due to the runout can be suppressed. Therefore, there is an effect that the upper limit of the detection accuracy of the rotation amount can be improved accordingly. Further, even if the shake becomes large with time, it is possible to suppress the deterioration of the detection accuracy due to the shake, so that it is possible to obtain stable and high detection accuracy with time. Therefore, the potentiometer can be used by the rotation detector support mechanism in the actuator for the fuel control valve, which requires high accuracy.

According to the present invention, the housing and the output shaft member rotatably arranged with respect to the housing,
A rotation driving unit that rotationally drives the output shaft member, a rotor that is fixed to the output shaft member so as to rotate around the same rotation shaft, and a rotation amount detection signal corresponding to the rotation amount of the rotor. Since the rotation detector having a stator for outputting and the holding member for holding the stator on the housing in a swingable manner by following the deflection of the output shaft member in a direction perpendicular to the rotation shaft, the output shaft is provided. The holding member absorbs the deflection of the member in the direction perpendicular to the rotation axis, and the change in the posture of the stator around the rotation axis can be suppressed accordingly.

As a result, since the rotation of the stator with respect to the rotor due to the runout of the output shaft member in the direction perpendicular to the rotation axis can be suppressed, the change of the rotation amount detection signal due to the runout can be suppressed. Therefore, there is an effect that the upper limit of the detection accuracy of the rotation amount can be improved accordingly. Further, even if the shake becomes large with time, it is possible to suppress the deterioration of the detection accuracy due to the shake, so that it is possible to obtain stable and high detection accuracy with time. Therefore, the potentiometer can be used by the rotation detector support mechanism in the actuator for the fuel control valve, which requires high accuracy.

[Brief description of drawings]

FIG. 1 is a top view and a partially cutaway sectional view showing an internal structure of an actuator for a fuel control valve according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part for explaining an operation in a case where the output shaft member of the actuator according to the first embodiment of the present invention touches a direction perpendicular to a rotation axis thereof.

3A and 3B are a top view and a partially cutaway sectional view showing an internal structure of an actuator for a fuel control valve according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a main part for explaining an operation in a case where an output shaft member of an actuator according to a second embodiment of the present invention touches a direction perpendicular to a rotation axis thereof.

5A and 5B are a top view and a partially cutaway sectional view showing an internal structure of an actuator for a fuel control valve according to a third embodiment of the present invention.

FIG. 6 is a perspective view of a main part for explaining an operation in a case where an output shaft member of an actuator according to a third embodiment of the present invention touches a direction perpendicular to a rotation axis thereof.

FIG. 7 is a cross-sectional view showing a conventional actuator.

FIG. 8 is an explanatory diagram for explaining a problem of a conventional actuator.

[Explanation of symbols]

1 housing 3 Output shaft member (rotating member) 4 Drive motor (rotation drive means) 6 Drive transmission gear group (rotational drive means) 8 Potentiometer (rotation detector) 8a rotor 8b stator 9 Floating substrate (holding member) 11 First link arm (holding member) 12 Second link arm (holding member) 13 Interval holding arm (holding member) 14 Third link arm (holding member) 15 4th link arm (holding member) 16 L-type link arm (holding member) 17 Fixing screw (holding member) 18 Elastic spacer (holding member)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 2-35251 (JP, A) Actual Development No. 4-32236 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 7/00-7/34 G01B 21/00-21/32 G01D 5/00-5/252 G01B 5/39-5/62

Claims (2)

(57) [Claims] 1. A rotation amount detecting device for detecting the rotation amount of a rotating member rotating in a housing, comprising: a rotor fixed so as to rotate around the same rotation axis with respect to the rotating member; A rotation detector having a stator that outputs a rotation amount detection signal according to a rotation amount, and the stator is swingably held on the housing by following a deflection of the rotating member in a direction perpendicular to a rotation axis. A rotation amount detection device comprising: a holding member. 2. A housing, an output shaft member rotatably arranged with respect to the housing, a rotation driving means for rotationally driving the output shaft member, and a periphery of the same rotary shaft with respect to the output shaft member. A rotation detector having a rotor fixed so as to rotate at a rotation angle, and a stator outputting a rotation amount detection signal according to the rotation amount of the rotor, and the stator in a direction perpendicular to the rotation shaft of the output shaft member. And a holding member that holds the housing on the housing so that the housing is swingable in response to the deflection.