JP2002010578A - Actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator having excellent vibration-proof characteristic and durability. SOLUTION: This actuator 1 comprises an AC servo motor 2 having a rotation output shaft, a reduction gear 3 which is coupled with one end of the rotation output shaft of the AC servo motor 2, an output lever 6 which is swiveled with an output shaft of the reduction gear 3 and a rotating position sensor 7 which is provided at the other end side of the rotating output shaft to detect the rotating position of the rotation output shaft. Moreover, the actuator 1 is also provided with a non-contact type position sensor 8 which changes the rotating position sensor 7 to a brushless resolver type sensor, controls drive of the AC servo motor 2 based on detection by the rotating position sensor 7 and detects swiveling position of the output lever 6 to control rotation of the AC servo motor 2 based on detection by the position sensor 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an actuator for controlling a fuel pump of an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine such as a ship, a desired output is generated by controlling a fuel pump for discharging fuel. The control of the fuel pump is performed by an actuator. Conventionally, as this type of actuator, an actuator including an AC servomotor, a speed reducer connected to a rotation output shaft of the AC servomotor, and an output lever connected to the output shaft of the speed reducer is known. I have. The actuator drives an AC servomotor in accordance with an operator's command to rotate the rotary output shaft, and the rotation of the rotary output shaft is reduced by a speed reducer and transmitted to the output lever. The output lever is swung by transmission from the speed reducer, and discharges fuel from the fuel pump according to the swing angle.

Further, the actuator is provided with a rotation position sensor for detecting the number of rotations and the rotation position of the rotation output shaft of the AC servomotor in order to control the fuel pump.
An absolute encoder is used as the rotation position sensor. Then, the actuator controls the activation of the AC servomotor based on the rotational position detected by the rotational position sensor. In addition, the actuator detects the swing position of the output lever based on the rotation speed and the rotation position detected by the rotation position sensor, and controls the rotation of the rotation output shaft of the AC servomotor to discharge the fuel by the fuel pump. It controls the amount.

[0004]

The conventional actuator must have an absolute encoder in order to control the activation of the AC servomotor and to control the swing of the output lever. This absolute encoder includes a rotating plate with a slit, a light emitting diode, a photodiode, and the like.
Since it is attached to the rotary output shaft of the servomotor, it has a structure that is weak against vibration. Therefore, when an actuator is arranged around an internal combustion engine such as a ship, the absolute encoder is affected by vibrations caused by driving of the internal combustion engine, and is driven by AC.
There is a possibility that the rotation speed and the rotation position of the servomotor may not be detected, and there is a problem that the vibration resistance and the durability are poor.

[0005] In the absolute type encoder,
When the rotation of the rotation output shaft of the AC servomotor exceeds 360 °, it is necessary to use a storage device for storing the number of rotations of the rotation output shaft. This storage device is provided with a backup power supply to enable detection of the number of rotations of the rotary output shaft and the like even when the power supply fails, but this backup power supply is also vulnerable to vibration.

An object of the present invention is to provide an actuator excellent in vibration resistance and durability.

[0007]

According to a first aspect of the present invention, there is provided an AC servomotor having a rotary output shaft, and a rotation output shaft connected to one end of the rotary output shaft of the AC servomotor. Actuator provided with a speed reducer that outputs after deceleration, an output lever that is oscillated by the output shaft of the speed reducer, and a rotation position sensor that is provided at the other end of the rotation output shaft and that detects a rotation position of the rotation output shaft. It is. And
The actuator uses a brushless resolver type rotation position sensor, controls the activation of the AC servomotor based on the detection by the rotation position sensor, and provides a non-contact type position sensor that detects the swing position of the output lever. Is used to control the swing position of the output lever. In the actuator, instead of the conventional absolute type encoder, the rotation position (range from 0 ° to 360 °) of the rotation output shaft of the AC servomotor is detected by a brushless resolver, and the output lever swings by a non-contact type position sensor. The position is detected. This brushless resolver is composed of a detection unit having a winding, a rotary transformer, and the like, and has a mechanically strong structure as compared with the encoder.
The rotation position of the rotation output shaft of the servomotor can be detected. In addition, the rotation position of the rotation output shaft and the swing position of the output lever are detected by a brushless resolver and a position sensor, and the start and rotation of the AC servomotor are controlled based on these detections. There is no need to memorize. For this reason, it is not necessary to arrange a storage device for storing the number of revolutions of the rotation output shaft and the like and a backup power supply which is weak against vibration around the internal combustion engine.

According to a second aspect of the present invention, a position sensor for detecting a swing position is provided between an output lever and a speed reducer, and a detection object which rotates together with an output shaft of the speed reducer, and a position sensor for detecting the position sensor. 2. The actuator according to claim 1, wherein a swing position of the output lever is detected by detecting a gap between the output lever and the actuator. The position sensor that detects the swinging position is provided between the output lever and the speed reducer to detect a gap between the detection target that rotates with the output shaft of the speed reducer and the detection unit of the position sensor. There is no contact interference with the position sensor, and it is possible to prevent the position sensor from being damaged even if the output lever swings greatly.

According to a third aspect of the present invention, there is provided the actuator according to the first or second aspect, wherein the position sensor for detecting the swing position is an eddy current potential sensor. This eddy current potential sensor has a very simple structure, is small in size, has high sensitivity, and is excellent in vibration resistance. Therefore, it can detect the swing position of the output lever even when it receives vibration of the internal combustion engine.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An actuator according to an embodiment of the present invention will be described with reference to the drawings. FIG.
It is a perspective view of an actuator, and shows the state connected to the driver and the fuel pump.

In FIG. 1, an actuator 1 has an AC
The servo system includes a servomotor 2, a speed reducer 3, a detected object 5 and an output lever 6, and constitutes a drive system in which the detected object 5 and the output lever 6 are swung by the AC servomotor 2 and the speed reducer 3. Further, the actuator 1 includes a rotational position sensor 7, a position sensor 8, and a driver 9, and these constitute a control system for controlling activation and rotation of the AC servomotor 2.

The AC servomotor 2 of the drive system is, for example,
It is composed of a synchronous AC servomotor. The AC servomotor 2 includes a rotation output shaft, a rotor (permanent magnet) provided on the rotation output shaft, and U, V, and W-phase stator coils provided on a stator 10 that covers the rotor. This AC
The servo motor 2 rotates a rotary output shaft by causing a driver 9 to flow a three-phase alternating current through each stator coil.

The speed reducer 3 is constituted by a planetary gear mechanism arranged in a main body case 11. Also, reducer 3
Is connected to one end of the rotation output shaft of the AC servomotor 2, and is integrated with the AC servomotor 2 by attaching the stator 10 to the main body case 11. The speed reducer 3 reduces the rotation of the rotation output shaft of the AC servomotor 2 to swing the object 5 and the output lever 6.

The detected object 5 is constituted by a rotating flat cam disposed in a casing 12 and is connected to an output shaft of the speed reducer 3. In addition, the detection target 5 includes a swing shaft 13 that extends into the casing 12 concentrically with the output shaft of the speed reducer 3, and the swing shaft 13 protrudes from the inside of the casing 12. The outer periphery of the detected object 5 is formed in a cam shape 19 that is symmetrical about the swing shaft 13 (the output shaft of the speed reducer 3). The left and right cam shapes 19 gradually decrease the radius from the axis of the swing shaft 13 from the lower end to the upper end of the detection target 5. Further, the main body case 11 of the speed reducer 3 is attached to the casing 12 and is integrated with the speed reducer 3. The open end of the casing 12 is inserted into the cover plate 14 while the swing shaft 13 of the detection target 5 is inserted therethrough.
It is closed by The detected object 5 is swung by the rotation decelerated by the speed reducer 3.

The output lever 6 is inserted into a swing shaft 13 protruding from the casing 12 and is fastened and fixed to the outer periphery of the swing shaft 13 by a plurality of bolts 15 and the like. Also,
The output lever 6 extends perpendicular to the axis of the swing shaft 13 toward the upper end of the detection target 5, and has a connection hole 20 formed at the upper end. The link mechanism 16 connected to the fuel pump P is connected to the connection hole 20 of the output lever 6. The output lever 6 is swung together with the detected object 5 by the rotation reduced by the speed reducer 3, and discharges fuel from the fuel pump P according to the swing.

The rotational position sensor 7 of the control system is constituted by a brushless resolver (hereinafter referred to as a resolver 7), and is provided at the other end of the rotational output shaft of the AC servomotor 2 (opposite to the speed reducer 3). The resolver 7 is a cylindrical case 1
7, consisting of a detection unit and a rotary transformer. The cylindrical case 17 houses the detection unit and the rotary transformer. The detection unit of the resolver 7 includes a detection stator coil provided on the inner periphery of the cylindrical case 17 and a detection rotor coil provided on the rotary output shaft so as to face the detection stator coil. Further, the rotary transformer of the resolver 7 includes a stator transformer provided on the inner periphery of the cylindrical case in parallel with the detection stator coil, and a rotor transformer provided on the rotary output shaft facing the stator transformer. The resolver 7 excites the detection rotor coil with an AC voltage from the rotor transformer, and induces an output voltage on the detection stator coil. Since this output voltage changes according to the rotation angle of the rotation output shaft of the AC servomotor 2, the resolver 7 detects the rotation position of the rotation output shaft based on the change in output power. Then, the resolver 7 outputs the rotational position (U, V, W signal) of the rotary output shaft with respect to the U, V, W phase coils of the AC servomotor 2 to the driver 9.

The position sensor 8 is composed of a non-contact type eddy current potential sensor. The position sensor 8 is disposed between the output lever 6 and the speed reducer 3, and is attached to a casing 12 that houses the detection target 5. The position sensor 8 includes a detection head 18 including a coil, a capacitor, and the like.
The detection head 18 is provided with a cam shape 19 of the detection target 5.
In a non-contact manner. The position sensor 8 indirectly detects a swing position of the output lever 6 by detecting a gap d between the detection target 5 and the cam shape 19 by the detection head 18. If the detected object 5 is constituted by a rotating plane cam,
The gap d fluctuates depending on the swing angle of the detection target 5. When swinging the detection object 5, the position sensor 8
A high-frequency magnetic field is generated by the detection head 18 and an eddy current is generated in the cam shape 19 of the detection target 5. This eddy current changes the impedance of the coil according to the gap d that fluctuates due to the swing of the detection target 5. The position sensor 8 detects the swing position of the output lever 6 that swings together with the detection target 5 by detecting the gap d based on a change in the impedance of the coil. Further, the position sensor 8 outputs to the driver 9 a feedback signal indicating a gap d with the detected object 5.

The driver 9 includes a power circuit section 21 and a control section 22. The power circuit unit 21 is connected to the AC servomotor 2 and converts a three-phase AC of an AC power supply into an AC suitable for the AC servomotor 2. The control unit 22 is connected to an external device such as a personal computer, and inputs commands such as a swing angle, a swing direction, and a swing speed for the output lever 6. The control unit 22 is connected to the resolver 7 and inputs the rotational position (U, V, W signals) detected by the resolver 7. The control unit 22 is connected to the position sensor 8 and inputs a feedback signal detected by the position sensor 8. The driver 9 determines the rotation position of the rotation output shaft of the AC servomotor 2 in the control unit 22 based on the input of the rotation position, and controls the activation of the AC servomotor 2. Further, the driver 9 determines the swing position of the output lever 6 in the control unit 22 based on the input of the feedback signal, and controls the rotation of the AC servomotor 2. The swing position of the output lever 6 is determined by inputting a table indicating the relationship between the feedback signal and the swing angle of the detected object 5 to the control unit 22 in advance, and comparing the feedback signal with the table.

FIGS. 2 and 3 show specific arrangement examples of the detection target 5, the output lever 6, and the position sensor 8 shown in FIG.
Is shown in 2 is a partial cross-sectional view as viewed from AA in FIG. 1, and FIG. 3 is a partial cross-sectional view as viewed from BB in FIG.

In FIG. 2 and FIG.
Are externally fitted to the main body case 11 of the speed reducer 3 and are integrated by a plurality of bolts 25. The casing 12 has a flange 26 projecting radially outward.
A bracket 28 is attached to the flange 26 by bolts and nuts 27, and the actuator 1 is disposed around the internal combustion engine such as a ship with the bracket 28. Further, the casing 12 is provided with a mounting hole portion 29 that opens to face the cam shape 19 of the detection target 5. The mounting hole 29 is located in the middle of the cam shape 19 of the detection target 5 and opens into the casing 12.
The output shaft 33 of the speed reducer 3 is rotatably projected into the casing 12. At the tip of the output shaft 33, an insertion groove 34 that opens toward the detection target 5 is formed.

The detected object 5 has substantially the same size as the output shaft 33 of the speed reducer 3 and is arranged to be swingable in the casing 12. The thickness t of the cam shape 19 of the detection target 5 is sufficient to keep the sensitivity of the position sensor 8 high. The detection target 5 has a protrusion 35 protruding toward the output shaft 33, and is connected to the output shaft 33 by fitting the protrusion 35 into an insertion groove 34 of the output shaft 33. Further, the detection target 5 is fixed to the output shaft 33 by a plurality of bolts 36 screwed from the lid plate 14 side.
The swing shaft 13 of the detection target 5 projects from the casing 12 to the outside of the casing 12 through the insertion hole 37 of the cover plate body 14. The swing shaft 13 has a stepped shape whose diameter is reduced on the distal end side.

The output lever 6 is fitted around the tip of the swing shaft 13 and is in contact with the step of the swing shaft 13. The output lever 6 is fastened and fixed to the outer periphery of the swing shaft 13 by a plurality of bolts 15 and fastening members 38 provided around the outer periphery of the swing shaft 13. Output lever 6
Extends perpendicular to the axis of the swing shaft 13.

The position sensor 8 comprises a main body case 39 and the detection head 18. This body case 39
Are arranged around the mounting hole 29 and are firmly attached to the casing 12 by bolts, welding, or the like. The detection head 18 is fixed to the main body case 39 and the mounting hole 29
Through the cam shape 19 of the detection target 5 in a non-contact manner. The detection head 18 is disposed at an intermediate position in the thickness direction of the cam shape 19 in the middle of the extension of the cam shape 19 of the detection target 5. Thereby, even if the object 5 is swung forward and backward, the gap d between the object 5 and the object 5 can be detected by the detection head 18 of the position sensor 8.

FIGS. 4 and 5 show the specific shapes of the detected object 5 shown in FIGS. FIG. 4 is a diagram viewed from CC in FIG. 2, and shows the entire front surface of the detection target 5. In FIG. 4, the detection target 5 is formed of a metal circular material capable of generating an eddy current, and has a symmetrical shape with respect to a center line b orthogonal to the axis a of the swing shaft 13. A left-right symmetrical cam shape 19 is formed on the outer periphery of the detected object 5 by processing the outer periphery of a circular material.
By making the detected object 5 bilaterally symmetric, the actuator 1 can cope with both the left-rotation specification and the right-rotation specification. Usually, either the left or right cam shape 19 is used. In each of the cam shapes 19, the radius R of the swing shaft 13 from the axis a is gradually reduced as the angle θ increases from the lower end of the detected object 5 with respect to the center line b. Each cam shape 19 is set based on the relationship with the feedback signal of the detection head 18 shown in FIG. In FIG. 5, when the radius R of each cam shape 19 is proportionally reduced, the feedback signal of the detection head 18 becomes an output that gradually saturates according to the swing angle of the detection target 5. On the other hand, if the radius R of each cam shape 19 is gradually increased without being proportional, the detection head 18
Is an output of a straight line f that rises in proportion to the swing angle of the detected object 5. In the detected object 5, the radius R of the cam shape 19 is not proportional but is gradually increased in order to make the feedback signal of the detection head 18 a proportional straight line f. This allows
The feedback signal indicating the gap d detected by the position sensor 8 can be directly input to the control unit 22 of the driver 9 without converting the feedback signal into a signal corresponding to the control unit 22 by the conversion device.

Next, control of the fuel pump P by the actuator 1 will be described with reference to FIGS. In addition,
Before controlling the fuel pump P, the detected object 5 and the output lever 6 are in the state shown in FIGS.
Further, a table corresponding to the proportional straight line f in FIG. 5 is input to the control unit 22 of the driver 9.

In order to control the control of the fuel pump P, the operator inputs a command signal such as a swing angle for the output lever 6 to the driver 9 using an external command device. Driver 9
Receives a command signal, inputs a rotation position signal from the resolver 7, and the control unit 22 determines the rotation position of the rotation output shaft of the AC servomotor 2 based on the rotation position signal. Then, the control unit 22 outputs a control signal for activating the AC servomotor 2 to the power circuit unit 21 based on the determination of the rotational position and the command signal. The power circuit unit 21 outputs a three-phase alternating current suitable for the AC servomotor 2 to the U, V, and W phase stator coils according to the control signal. Thereby, the driver 9 controls the activation of the AC servomotor 2 and rotates the rotation output shaft.

The rotation of the AC servomotor 2 is reduced by the speed reducer 3 and transmitted from the output shaft 33 to the object 5 and the output lever 6. Thus, the detection target 5 and the output lever 6 are swung clockwise, for example.

When the swing of the object 5 starts, the detection head 18 of the position sensor 8 detects the gap d with the object 5 and outputs it to the control unit 22 of the driver 9 as a feedback signal. . At this time, as the swing angle increases due to the cam shape 19 of the detection object 5, the detection head 18
As the distance increases, the gap d increases, whereby the feedback signal also increases proportionally.

The controller 22 of the driver 9 determines the swing position of the output lever 6 swinged together with the object 5 by comparing the feedback signal with a table indicated by a straight line f in FIG. Then, the control unit 22 outputs a control signal to the power circuit unit 21 based on the swing position and the command signal so that the output lever 6 has the swing angle of the command signal. The power circuit section 21 controls the rotation of the AC servomotor 2 based on the control signal to swing the output lever to the swing angle of the command signal. Thus, the fuel pump P connected to the output lever 6 by the link mechanism 16
Discharges fuel in accordance with the swing angle of the output lever 6. Then, the actuator 1 detects the swinging position of the output lever 6 based on the gap d with the detected object 5 by the position sensor 8 and controls the rotation of the AC servomotor 1 so that the fuel pump P Control the discharge amount.

In the actuator 1 according to the embodiment of the present invention, the rotational position of the rotation output shaft of the AC servomotor 2 is detected by the brushless resolver 7, and the swing position of the output lever 6 is detected by the non-contact type position sensor 8. It has a configuration. The brushless resolver 7 is composed of a detection unit having a winding and a rotary transformer, and has a mechanically robust structure as compared with an absolute type encoder.
The rotational position of the rotary output shaft can be detected. Further, the rotation position of the rotation output shaft and the swing position of the output lever 6 are detected by the brushless resolver 7 and the position sensor 8, and the start and rotation of the AC servomotor 2 are controlled based on these detections. There is no need to store the number of revolutions.
For this reason, a storage device for storing the number of rotations of the rotation output shaft,
It is no longer necessary to arrange a backup power supply that is sensitive to vibration around the internal combustion engine. As a result, the actuator 1 can have excellent vibration resistance and durability. Even when the actuator 1 is arranged around an internal combustion engine such as a ship, the rotational position of the rotation output shaft of the AC servomotor 2 and the swing of the output lever 6 can be improved. Position can be detected.

The position sensor 8 detects a gap between the detection target 18 rotating with the output shaft 33 of the speed reducer 3 and the detection head 18 of the position sensor 8 between the output lever 6 and the speed reducer 3. Therefore, there is no contact interference between the position sensor 8 and the output lever 6, and it is possible to prevent the position sensor 8 from being damaged even if the output lever 6 swings greatly.

Further, the eddy current potential sensor serving as the position sensor 8 has a very simple structure, is small, has high sensitivity,
Because of its excellent vibration resistance, the swing position of the output lever 6 can be detected even when receiving vibration of an internal combustion engine such as a ship.

In the actuator according to the present invention, FIG.
The present invention is not limited to the configuration shown in FIGS. (1) The detection target 5 does not need to have a left-right symmetrical shape, and the cam shape 19 may be formed only on the side of the position sensor 8 which is opposed to the detection head 18 without contact. (2) The cam shape 19 of the detected object 5 is determined from the upper end of the detected object 5 toward the lower end with respect to the center line b.
The radius R of the swing shaft 13 about the axis a may be gradually reduced. (3) The application example of the actuator 1 is not limited to the fuel pump P that discharges fuel to an internal combustion engine such as a ship, but may be applied to a fuel pump of another internal combustion engine. (4) As the position sensor 8, a sensor using an eddy current potential sensor has been described, but the present invention is not limited to this, and a sensor having excellent vibration resistance can be used.

[0034]

According to the first aspect of the present invention, a brushless resolver having a mechanically robust structure is used as compared with the absolute type encoder, so that the AC servomotor can be operated even when the internal combustion engine is vibrated. The rotation position of the rotation output shaft can be detected. In addition, the rotation position of the rotation output shaft and the swinging position of the output lever are detected by a brushless resolver and a position sensor, and the start and rotation of the AC servomotor are controlled based on these detections. You don't have to. For this reason, it is not necessary to arrange a storage device for storing the number of rotations of the rotation output shaft or a backup power supply that is susceptible to vibration around the internal combustion engine. As a result,
An actuator having excellent vibration resistance and durability can be obtained.

According to the second aspect of the present invention, the position sensor detects a gap between the output lever and the speed reducer, between the detection target rotating with the output shaft of the speed reducer and the detection head of the position sensor. In addition, there is no contact interference between the position sensor and the output lever, and it is possible to prevent the position sensor from being damaged even if the output lever swings greatly.

According to the third aspect of the present invention, the eddy current potential sensor serving as the position sensor has a very simple structure, is small in size, has high sensitivity, and has excellent vibration resistance. However, the swing position of the output lever can be detected. As a result, an actuator having excellent vibration resistance and durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an actuator according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the actuator as viewed from AA in FIG. 1;

FIG. 3 is a partial cross-sectional view of the actuator as viewed from BB in FIG. 2;

FIG. 4 is a view showing the entire front surface of the detection object 5 viewed from BB in FIG. 2;

FIG. 5 is a graph showing a state of a feedback signal of a position sensor for setting a cam shape of an object to be detected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator 2 AC servomotor 3 Reduction gear 5 Detected object 6 Output lever 7 Rotational position sensor (brushless resolver) 8 Position sensor (Eddy current potential sensor) 9 Driver 18 Detection head (Detection part) 19 Cam shape 21 Power circuit part 22 Control part P Fuel pump

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuichi Furuichi 1-16-1 Fukuyoshidai, Nishi-ku, Kobe-shi, Hyogo Inside Nabco Seishin Plant Co., Ltd. (72) Inventor Shinya Takada 1, Fukuyoshidai, Nishi-ku, Kobe-shi, Hyogo 1617-1 Nabco Seishin Plant Co., Ltd. (72) Inventor Tomio Shigaki 1-17-1 Fukuyoshidai, Nishi-ku, Kobe City, Hyogo Prefecture F-term (reference) 3G060 AA00 AC09 BA01 DA00 FA06 5H607 AA00 AA12 BB01 BB07 BB09 BB26 CC03 CC05 DD19 EE36 FF06 5H611 AA01 BB07 BB08 PP07 QQ03 RR00 UA08

Claims (3)

[Claims] An AC servomotor having a rotary output shaft, a reducer connected to one end of the rotary output shaft of the AC servomotor for reducing the rotation of the rotary output shaft and outputting the reduced output, and an output shaft of the reducer An actuator including a swingable output lever and a rotation position sensor provided at the other end of the rotation output shaft and detecting a rotation position of the rotation output shaft, wherein the rotation position sensor is a brushless resolver type, and A non-contact type position sensor for controlling the start of the AC servomotor based on the detection by the rotation position sensor and detecting the swinging position of the output lever is provided, and the AC based on the detection by the position sensor.
An actuator, wherein the rotation of a servomotor is controlled. 2. A position sensor for detecting the swing position,
Detecting a gap between a detection object provided between the output lever and the reduction gear and rotating with the output shaft of the reduction gear, and a detection unit of the position sensor to detect a swing position of the output lever The actuator according to claim 1, wherein 3. A position sensor for detecting the swing position,
3. The actuator according to claim 1, wherein the actuator is an eddy current potential sensor.