JP2008274971A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of sensing the stroke accurately while versatility and an inexpensive construction are ensured. <P>SOLUTION: Complying with the rotation of an annular magnet MG, sensors SA and SB emit a periodic signal which rises when the N-pole confronts and falls when the S-pole confronts. One cycle of such signals is generated with a turn of a rotary shaft 102a. Accordingly the revolution of the rotary shaft is determined by counting pulses of the signal. The sensors mounted 90 degs, dislocated emit wavy signals with their phases shifted from each other, so that the waveform of a sensor is advanced or retarded with respect to the other sensor according to the rotational direction. When the phase of the waveform of the sensor SB is advanced from that of the sensor SA, it is known that the annular magnet is rotating clockwise. Otherwise, the magnet is rotating counterclockwise. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric actuator that is particularly suitable for use in ships and the like.

In a relatively small vessel that drives a screw with an internal combustion engine, the screw rotation in the forward direction and the screw rotation in the reverse direction are switched via a wire connected to a lever operated by the operator. Then, the dog clutch of the forward / reverse switching mechanism is switched and engaged with the forward gear or the reverse gear. However, in recent years, there has been a demand for switching the dog clutch by electric drive for labor saving. Here, for example, various actuators for vehicles have been developed (see Patent Document 1), and it is conceivable to divert them.
US Pat. No. 6,101,889

  By the way, in such an actuator, it is necessary to accurately detect the position of the dog clutch in the forward / reverse switching mechanism of the ship and perform the operation. In the actuator of Patent Document 1, the rotation angle is transmitted to the potentiometer via the sensor gear in accordance with the stroke of the movement axis, thereby detecting the absolute position of the movement axis to obtain the stroke.

  However, in such a conventional configuration, as the stroke of the moving shaft becomes longer, the gear ratio of the sensor gear has to be increased. As a result, the gear size becomes larger or the sensor gear needs to be multistaged. This causes an increase in size of the actuator. In addition, the accuracy of the rotation angle detected by the potentiometer may be reduced due to backlash or pitch error of the sensor gear. Furthermore, even if the dimensional accuracy and assembly accuracy of the gear are improved, if a potentiometer is used in a place where the environmental temperature is high due to heat generated by the motor, such as in an actuator, a zero point shift may occur and high detection accuracy may not be obtained. There is also. On the other hand, if the potentiometer is attached outside the housing, the potentiometer can be used in a room temperature environment. However, as a result, it becomes easy to be exposed to seawater, fuel, etc., and it is necessary to make it waterproof and oil-proof, and further shield against electromagnetic waves. It is necessary to provide a separate structure, which may increase the cost.

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide an actuator capable of detecting a stroke with high accuracy while being general-purpose and low-cost.

The actuator of the present invention is an actuator that drives a driven member to operate a forward / reverse switching mechanism of a ship.
A housing;
An electric motor attached to the housing and having a rotating shaft;
A driving mechanism for driving the driven member by transmitting a rotational force from the rotating shaft;
A sensor that is disposed in the housing and outputs a pulsed signal corresponding to the rotation of the rotating shaft of the electric motor;
And a control device that determines a stroke and a direction of the driven member based on an output from the sensor.

  According to the present invention, since the stroke of the driven member can be detected by counting pulses of a signal corresponding to the rotation of the rotating shaft of the electric motor output from the sensor, a potentiometer is used as in the prior art. Since it is possible to omit the sensor gear that was necessary in this case, it is possible to reduce the size. In addition, since the stroke can be detected only by counting the number of pulses of the signal, high-precision detection can be performed while being inexpensive and hardly affected by temperature. In addition, since the sensor can be housed in the housing, there is no risk of being exposed to seawater or fuel, so a simple structure can be achieved, and it is less susceptible to electromagnetic waves, thus improving the reliability of the system. It is.

  It is preferable that the sensor be built in the electric motor because the sensor can be protected even if the electric motor is mounted outside the housing.

  When the control device detects that the driven member is in the neutral position of the forward / reverse switching mechanism and performs learning control, a switching operation with higher accuracy is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of an outboard motor using the actuator according to the present embodiment. FIG. 2 is a cross-sectional view of the actuator according to the present embodiment.

  In FIG. 1, the outboard motor 2 has a casing 2a fixed to the hull 1 and a cowling 2b attached to the upper portion thereof. An engine (not shown) in which the output shaft 3 is extended to the casing 2a is mounted inside the cowling 2b. A bevel gear 3 a is attached to the lower end of the output shaft 3.

  A propeller shaft 4 is horizontally disposed below the casing 2a and is rotatably supported. In the figure of the propeller shaft 4, the right end side protrudes outward from the casing 2 a, and the propeller 5 is attached to the end portion.

  The propeller shaft 4 passes through a forward bevel gear 6 and a reverse bevel gear 7 that mesh with the bevel gear 3 a, and a dog clutch 8 is disposed between the bevel gears 6 and 7. The dog clutch 8 can move relative to the propeller shaft 4 in the axial direction but can rotate integrally, and the bevel gears 6 and 7 can rotate relative to each other. Although not shown, the dog clutch 8 has protrusions facing in both axial directions. When the dog clutch 8 moves to the left in the figure, the protrusion engages with the concave portion of the bevel gear 6, and the dog clutch 8 and the bevel gear 6. And rotate together. On the other hand, by moving to the right in the figure, the protrusion engages with the concave portion of the bevel gear 7, and the dog clutch 8 and the bevel gear 7 rotate integrally.

  The dog clutch 8 is driven in the axial direction by a cam shaft 9. The cam shaft 9 is coupled so as to be displaced in the axial direction in accordance with the rotation of the operation shaft 10. The operation shaft 10 is connected via a link member 11 to a moving shaft 117 of the actuator 100 disposed at the lower portion of the cowling 2b. The dog clutch 8, the cam shaft 9, and the operation shaft 10 constitute a forward / reverse switching mechanism.

  In FIG. 2, a cylindrical housing 101 includes an aluminum housing main body 101A, an aluminum or resin cover member 101B assembled to the end surface of the housing 101 by bolts B, and a motor bracket 101C. A seal member 120 (O-ring or the like) is accommodated in a circumferential groove provided on the abutting surface of the housing main body 101A. When the abutting surface of the cover member 101B is opposed and bolted, both abutments It is designed to seal between the faces. A motor chamber 101a and a screw shaft chamber 101b are formed in the housing main body 101A. A motor 102 is disposed in the motor chamber 101a. The motor 102 is fixed to a plate-shaped motor bracket 101C. The motor bracket 101C sandwiches an outer ring of a ball bearing 114 described later between the housing main body 101A and the motor chamber 101a of the housing main body 101A and the screw shaft chamber. It is attached so as to block 101b.

  A rotating shaft 102a of the electric motor 102 protrudes from the motor bracket 101C, and a metal first gear 103 is attached to the end of the rotating shaft 102a so as not to be relatively rotatable by press fitting. A resin-made second gear 105 is rotatably disposed around a long shaft 104 implanted in the motor bracket 101C, and meshes with the first gear 103 and the third gear 106. The third gear 106 made of resin is attached to the end portion of the screw shaft 107 so as not to be relatively rotatable by serration coupling.

  The screw shaft 107 is rotatably supported by a ball bearing 114 on the right end side in the drawing with respect to the housing main body 101A. The screw shaft 107 has a male screw groove 107a on the left end side.

  The screw shaft 107 passes through a cylindrical nut 115. A female screw groove 115a is formed on the inner peripheral surface of the nut 115 so as to face the male screw groove 107a, and a large number of balls 116 are formed in a spiral space (rolling path) formed by both the screw grooves 107a and 115a. It is arranged to roll freely. The nut 115 is provided with a detent (not shown) with respect to the housing main body 101A, and is relatively movable in the axial direction in the screw shaft chamber 101b, but is not relatively rotatable. A nut 115 as an axial movement element, a screw shaft 107 as a rotation element, and a ball 116 as a rolling element constitute a ball screw mechanism, which is driven by this ball screw mechanism and the following movement shaft 117. Configure the mechanism.

  The left end of the screw shaft 107 penetrates into a bag hole 117 a formed in a round shaft-shaped moving shaft 117. The right end of the moving shaft 117 in the drawing is coaxially fitted to the nut 115 and connected with a pin so as to move integrally. The moving shaft 117 is supported by the bush 118 so as to be movable in the axial direction with respect to the housing main body 101A, and a seal 119 is disposed on the left side (external side) of the bush 118, and the housing main body 101A and the moving shaft 117 are arranged. Prevents foreign matter such as seawater and dust from entering between. A hole 117b for connecting to the link member 11 is formed at the end of the moving shaft 117 protruding from the housing main body 101A.

  In FIG. 1, the wiring 102b of the motor 102 and the wirings 113b of sensors SA and SB, which will be described later, extend from the motor 102 to the outside of the actuator 100 through the sealed opening 101c of the housing body 101A, and further to the control unit ECU. It is connected. A breather hose 12 communicating with the inside of the actuator 100 is provided separately.

  FIG. 3 is a schematic diagram of the internal structure of the motor 102. FIG. 4 is a view of the configuration of FIG. 3 taken along line IV-IV and viewed in the direction of the arrow. 3 and 4, an annular magnet MG is attached to a rotating shaft 102a to which a rotor 102d is attached so as to rotate integrally. The annular magnet MG is magnetized in the semi-annular part MGs and the semi-annular part MGn with the rotating shaft 102a interposed therebetween. The semi-annular part MGs has an S pole on the outer peripheral side, and the semi-annular part MGn has an N pole on the outer peripheral side. In proximity to the annular magnet MG, the first sensor SA and the second sensor SB are attached to the inner wall of the motor housing 102c with a phase shift of 90 degrees around the axis of the rotating shaft 102a. The sensors SA and SB are preferably Hall ICs that detect magnetism.

  The stroke of the moving shaft 117 is determined by the amount of rotation of the rotating shaft 102a of the motor 102, the gear ratio of the reduction gears 103, 105, 106, and the lead of the ball screw mechanism. Of these, the gear ratio and the lead are known. Therefore, if the amount of rotation of the rotating shaft 102a can be accurately measured, the position of the dog clutch 8 can be detected.

  More specifically, a mode of detecting the stroke and the moving direction of the moving shaft 117 will be described. FIG. 5 is a diagram illustrating waveforms of output signals of the sensors SA and SB. As shown in FIG. 5, the sensors SA and SB are periodically pulsed so as to rise when the N pole faces and fall when the S pole faces according to the rotation of the annular magnet MG. Output a signal. A signal of one cycle is output by one rotation of the rotating shaft 102a. Therefore, the number of rotations of the rotating shaft 102a can be obtained by counting the number of pulses (rise, etc.) of the signal.

  On the other hand, the sensors SA and SB mounted with a 90 degree offset output signals with waveforms that are out of phase with each other, so that the waveform of one sensor advances or delays relative to the waveform of one sensor depending on the direction of rotation. Will be. By utilizing this, for example, as shown in FIG. 5A, when the phase of the waveform of the sensor SB advances with respect to the waveform of the sensor SA, the annular magnet MG rotates clockwise (CW in FIG. 4). You can see that it is rotating in the) direction. On the other hand, as shown in FIG. 5B, when the phase of the waveform of the sensor SB is delayed with respect to the waveform of the sensor SA, the annular magnet MG rotates counterclockwise (CCW) in FIG. You can see that Therefore, based on the output signals of the sensors SA and SB, the control device ECU can accurately determine the stroke and the moving direction of the moving shaft 117.

  In the conventional sensor, the position stored in the memory may be erased by removing the battery, or the necessary position may be shifted due to backlash inside the actuator, thereby losing sight of the home position. Therefore, for example, if the neutral switch NS (FIG. 1) for detecting the neutral position of the dog clutch 8 attached to the outboard motor is used and a signal at the neutral position is input to the control unit ECU, the time point is used as a reference. By initializing the output signals from the sensors SA and SB, it is possible to determine the stroke and moving direction of the moving shaft 117 to be moved, and perform highly accurate positioning.

  For example, as shown in FIG. 6, when the moving shaft 117 extends with respect to the actuator 100, it is the reverse position R, the contracted position is the forward position F, and the intermediate position is the neutral position N. . Here, as shown in FIG. 7, the control unit ECU stores (learns control) that the dog clutch 8 reaches the forward position F at the T-th pulse from the signal falling edge of the neutral switch NS. The position control can be performed with higher accuracy from the base point.

  As a modification, since the current value supplied to the motor 102 changes when the motor 102 is stationary at the abutting end of the moving shaft 117, as shown in FIG. By performing the control, more accurate position control may be performed, for example, the moving shaft 117 may be stopped before that.

  Next, the operation of the actuator 100 will be described. Here, since the bevel gear 3a is always meshed with both the forward bevel gear 6 and the reverse bevel gear 7, the bevel gear 6 to which power is transmitted from the bevel gear 3a as long as the internal combustion engine is operating. , 7 are rotating in opposite directions. However, in the neutral state, as shown in FIG. 1, since the dog clutch 8 is not engaged with any of the bevel gears 6 and 7, the power of the output shaft 3 is not transmitted to the propeller shaft 4 and the propeller 5 It will not rotate.

  Here, it is assumed that the operator operates a lever (not shown) in the forward direction from the neutral state. Then, in FIG. 2, electric power having a predetermined polarity is supplied to the motor 102, and the rotating shaft 102a rotates in a predetermined direction. Since the rotational force of the rotating shaft 102a is transmitted to the screw shaft 107 via the first gear 103, the second gear 105, and the third gear 106, the nut 115 is moved to the left in FIG. 4 according to the rotation of the screw shaft 107. It is displaced to. When the nut 115 is displaced to the left, the moving shaft 117 moves in the protruding direction, so that the link member 11 pivots in FIG. Accordingly, the operation shaft 10 rotates in a predetermined direction, the cam shaft 9 moves to the left via a cam mechanism (not shown), and the dog clutch 8 is engaged with the forward bevel gear 6. As a result, the power of the output shaft 3 can be transmitted to the propeller shaft 4 via the bevel gears 3a and 6 and the dog clutch 8, and the propeller 5 can be rotated forward.

  On the other hand, the control device ECU can input the signals of the sensors SA and SB so that the stroke and the direction can be determined as described above. Stop power supply to.

  On the other hand, when the operator operates a lever (not shown) in the reverse direction, in FIG. 2, electric power having a reverse polarity is supplied to the motor 102, and the rotating shaft 102 a rotates in the reverse direction. With this operation, the moving shaft 117 of the actuator 100 moves in the retracting direction. Accordingly, the operating shaft 10 rotates in the reverse direction via the link member 11 in FIG. 1, the cam shaft 9 moves to the right via the cam mechanism (not shown), and the dog clutch 8 is engaged with the reverse bevel gear 7. Let As a result, the power of the output shaft 3 can be transmitted to the propeller shaft 4 via the bevel gears 3a and 7 and the dog clutch 8, and the propeller 5 can be rotated in the reverse direction.

  According to the present embodiment, the stroke of the moving member 117 can be detected by counting the pulse of the signal corresponding to the rotation of the rotating shaft 102a of the motor 102, which is output from the sensors SA and SB that are Hall ICs. Since the sensor gear, which is necessary when using a potentiometer as in the prior art, can be omitted, it is possible to reduce the size. Further, since the stroke can be detected only by counting the number of pulses of the signal, high-precision detection can be performed while being inexpensive and hardly affected by temperature. In addition, since the sensors SA and SB can be accommodated in the motor housing 102c, since there is no fear of being covered with seawater or fuel, a simple structure can be achieved and the influence of electromagnetic waves is less likely to be obtained, thereby improving the reliability of the system. It is also possible.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. The actuator according to the present invention can be used not only for ships but also for vehicles and general industrial machines.

It is the schematic of the outboard motor using the actuator concerning this Embodiment. It is sectional drawing of the actuator concerning this Embodiment. 2 is a schematic view of an internal structure of a motor 102. FIG. It is the figure which cut | disconnected the structure of FIG. 3 by the IV-IV line and looked at the arrow direction. It is a figure which shows the waveform of the output signal of sensor SA, SB, and a horizontal axis is a time axis. It is a figure which shows the relationship between the position of a moving shaft, and the position of a dog clutch. It is a figure which compares and shows the fall of a neutral switch, and the output waveform of a sensor. It is a figure which compares and shows the electric current supplied to a motor, and the output waveform of a sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hull 2 Outboard motor 2a Casing 2b Cowling 3 Output shaft 3a Bevel gear 4 Propeller shaft 5 Propeller 6 Forward bevel gear 7 Reverse bevel gear 8 Dog clutch 9 Cam shaft 10 Operation shaft 11 Link member 12 Breather hose 100 Actuator 101 Housing 101A Housing body 101B Cover member 101C Motor bracket 101a Motor chamber 101b Screw shaft chamber 102 Motor 102a Rotating shaft 102b Motor wiring 102c Motor housing 102d Rotor 103 First gear 104 Long shaft 105 Second gear 106 Third gear 107 Screw shaft 107a Male thread groove 113b Sensor wiring 114 Ball bearing 115 Nut 115a Female thread groove 116 Ball 117 Moving shaft 117a Bag hole 117b Hole 118 Bush 119 Seal 120 Seal member B Belt ECU controller MG ring magnet MGn half annulus MGs half annulus NS neutral switch

Claims (3)

In an actuator that drives a driven member to operate a forward / reverse switching mechanism of a ship,
A housing;
An electric motor attached to the housing and having a rotating shaft;
A driving mechanism for driving the driven member by transmitting a rotational force from the rotating shaft;
A sensor that is disposed in the housing and outputs a pulsed signal corresponding to the rotation of the rotating shaft of the electric motor;
An actuator comprising: a control device that obtains a stroke and a direction of the driven member based on an output from the sensor.   The actuator according to claim 1, wherein the sensor is built in the electric motor.   The actuator according to claim 1, wherein the control device performs learning control by detecting that the driven member is in a neutral position of a forward / reverse switching mechanism.

Images