JP4549087B2 - Power steering device for small ships - Google Patents

Description

  The present invention relates to a power steering apparatus for a small boat, in which steering of an outboard motor equipped with one engine is power-assisted by an electric actuator.

  Conventionally, as a power steering device for a small ship, a technique of power assist using an electric motor has been proposed (see Patent Document 1).

This is because the operation of the steering handle arranged in the driver's seat is transmitted to the outboard motor with the engine that is steerably supported at the rear of the small ship through the wire, and the outboard motor is rotated according to the steering amount of the steering handle. On the other hand, a power assist mechanism is provided for rotating the outboard motor through the reduction gear with the rotational force of the electric motor. The assist force by the electric motor is controlled by an electronic control unit (ECU) in accordance with a steering torque signal from a torque sensor that senses a steering torque by a steering force acting on the wire portion, an engine speed signal of an outboard motor, and the like. I have to.
Japanese Patent No. 2652788

  However, in the above conventional example, in a small vessel equipped with one outboard motor, there is a problem that the small vessel turns unintentionally even if the driver tries to go straight ahead. This is because even if an attempt is made to keep the steering handle in a straight traveling state, a force for steering the handle is generated by the rotational force of the screw, and the outboard motor rotates to generate a turning force in the small vessel. For example, when the screw rotates clockwise as viewed from the rear of the small ship, a phenomenon occurs in which the small ship turns right.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a power steering device for a small boat that improves the straight traveling performance of the small boat.

In order to solve the above problems, the invention according to claim 1 of the present invention is based on the outboard motor main body disposed at the rear part of the hull so as to be turnable in the left-right direction with respect to the hull and the steering operation of the steering handle of the driver's seat. A steering mechanism for rotating the outboard motor, a torque sensor for detecting a steering torque of the steering handle, an assist means for power assisting the steering mechanism in a steering operation direction according to at least a detection signal of the torque sensor, A power steering device for a small ship, which includes a controller that takes in a detection signal of a torque sensor, calculates and outputs a current for driving the assist means, and the torque sensor is in a state in which the steering handle is in a straight traveling state when the small ship is traveling release the to detect the torque of the state not to handle operations for maintaining the straight, front The controller adds a predetermined value so as to cancel the detected the torque obtained by correcting the steering torque, and outputs a current to the assist means to produce the corrected steering torque.

According to a second aspect of the present invention, there is provided an outboard motor body disposed at the rear of the hull so as to be turnable in the left-right direction with respect to the hull, and steering for rotating the outboard motor in response to a steering operation of a steering handle of a driver's seat. A mechanism, a torque sensor for detecting a steering torque of the steering handle, an assist means for power assisting the steering mechanism in a steering operation direction at least in accordance with a detection signal of the torque sensor, and a detection signal of the torque sensor And a controller that outputs a current for driving the assist means, and the torque sensor includes a steering torque in the straight traveling state of the steering wheel and a straight traveling state during traveling of the small boat. detecting a torque when you remove your hand, the controller detects is in the torque sensor The steering torque and obtains the difference between the torque, and outputs a current to the assist unit so as to cancel the torque difference was.

The invention according to claim 3 is characterized in that the assist force of the steering mechanism is set according to the number of rotations of the screw .

  According to the power steering device for a small boat of the present invention, the drivability and straightness of the small boat can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a power steering apparatus for a small ship to which the present invention is applied. The gear is installed in a driver's seat of a hull 1 and converts a steering operation of a steering handle 2 into a push-pull operation of a push-pull cable 3. A device (steering mechanism) 4, a power assist device 5, and a link mechanism that is disposed at the rear of the hull 1 to which the outboard motor 6 is attached and turns the outboard motor 6 according to the push-pull operation of the push-pull cable 3. 7.

  As shown in FIG. 2, the outboard motor 6 is a bevel gear (not shown) built in the gear housing 12 via a drive shaft (not shown) built in the drive shaft housing 11. The outboard motor main body 6 </ b> A configured to transmit to the propeller 13 via the propeller 13 is generated, and the propulsion force of the small vessel is generated by the rotation of the propeller 13. The outboard motor main body 6 </ b> A is supported by a vertical shaft 14 </ b> A (pilot shaft) provided on the swivel bracket 14 so as to be rotatable in a horizontal plane. The swivel bracket 14 is supported by a clamp bracket 15 that holds the transom of the hull 1 and is fixed to the hull 1 via a horizontal axis 15A (clamp bracket shaft). The swivel bracket 14 and the outboard motor main body 6A It can be flipped up counterclockwise in the figure as viewed from the top.

  As shown in FIG. 3, the link mechanism 7 transmits the push-pull operation of the push-pull cable 3 to the steering bracket 16 that is fixed to the outboard motor main body 6 </ b> A and extends to the hull 1 side via the drag link 17. Thus, the outboard motor 6 is turned by steering. For this reason, the end fitting 3B of the outer cable 3A of the push-pull cable 3 is fixed to the clamp bracket 15, and the tip rod 3C of the inner cable of the push-pull cable 3 protruding from the end fitting 3B of the outer cable 3A is dragged. 17 is connected. In the illustrated example, the end fitting 3B of the outer cable 3A is configured to also serve as the clamp bracket shaft 15A by passing through the clamp bracket 15 and the swivel bracket 14 and being fixed to the clamp bracket 15 with a nut. Accordingly, the outboard motor main body 6A is rotated in the horizontal plane via the vertical axis 14A via the drag link 17 and the steering bracket 16 by the push-pull movement of the inner cable of the push-pull cable 3, and is steered. The drag link 17 and the steering bracket 16 constitute a link mechanism 7.

  The gear device 4 is constituted by a rack and pinion as shown in FIGS. 4 to 9, particularly FIG. 8. The rack gear 20 pushes and pulls the inner wire of the push-pull cable 3 by its movement. The pinion gear 21 is provided integrally with the output shaft 22. The output shaft 22 is connected to a steering shaft 23 connected to the steering handle 2 via a torsion bar 24 and is configured to receive a driving force from an electric motor 27 as an assist motor via a worm gear 25 and a worm wheel 26. ing. In other words, the output shaft 22 is rotatably supported on the gear case 19 by a tip-side bearing 22A and a large-diameter bearing 22B which are both ends of the pinion gear 21, and a worm wheel 26 is integrally fixed adjacent to the large-diameter bearing 22B. On the rear end (steering handle 2) side, the front end of the steering shaft 23 is rotatably supported, and the front end of the torsion bar 24 is fixed by serration or the like. Further, a torque pin 28 is disposed at the rear end of the output shaft 22 so as to protrude outward. The gear case 19 is fixed to the dashboard DB of the driver's seat with mounting screws.

  The steering shaft 23 is also rotatably supported by the gear case 19 by a bearing 29, the rear end portion is connected to the steering handle 2, and a torsion bar 24 having a rear end fixed by a pin is provided in the hollow interior. . A torque ring 30 is attached to the outer periphery of the steering shaft 23 so as to rotate integrally with a spline or serration and move in the axial direction.

  When the torque ring 30 transmits the steering torque generated by the operation of the steering handle 2 from the steering shaft 23 to the output shaft 22 via the torsion bar 24, the torque ring 30 outputs the output shaft according to the amount of twist generated in the torsion bar 24. 22 and the steering shaft 23 is converted into an axial movement of the torque ring 30, and this axial movement moves the detection pin 36 engaged with the circumferential groove in the axial direction. Sense as steering torque.

  The worm wheel 26 is engaged with the worm gear 25, and the worm gear 25 is rotatably supported by the gear case 19 as shown in FIG. 9, and the clutch plate 33 is axially movable at one end and integrally rotates. Are combined. The clutch plate 33 can be brought into and out of contact with a drive plate 34 that is rotationally driven by the assist motor 27. When a clutch coil (not shown) is excited, the clutch plate 33 comes into contact with each other to drive the driving force of the assist motor 27 to the worm gear. When the excitation to the clutch coil is released, the plates 33 and 34 are separated from each other, and the worm gear 25 and the worm wheel 26 are separated from the assist motor 27 and rotated by the output shaft 22. The assist motor 27 (electric motor), the worm gear 25, and the worm wheel 26 constitute the power assist device 5.

  FIG. 10 is a block diagram showing the controller of the electric motor, which is constituted by processing executed in the ECU and processing executed by the drive circuit 40 of the electric motor 27. Hereinafter, the process performed by ECU is demonstrated in detail. The processing executed in the ECU mainly includes a basic assist current determination process 50a, an auxiliary assist current determination process 50b, and an auxiliary assist current addition process 50c.

  The basic assist current determination process 50a is a process for determining the first basic assist current value according to the value of the output signal of the torque sensor 35, that is, according to the magnitude of the steering torque of the steering wheel. The basic assist current determination process 50a uses the data relating to the assist current value corresponding to the magnitude of the steering torque (the output signal value of the torque sensor 35) from the data stored in advance in the EEPROM as the first basic assist current. This is a process for determining the value. As shown in FIG. 11, the first basic assist current value is approximately proportional to the square of the value of the output signal of the torque sensor 35. Further, the increase / decrease of the assist amount is achieved by increasing / decreasing the assist amount by the changeover switch 49 provided in the vicinity of the steering wheel 2 and increasing / decreasing the steering torque as indicated by 1 to 3 in the figure. When increasing the steering torque, the increase in the drive current is increased, and when decreasing the assist amount, the increase in the drive current is suppressed according to the increase in the steering torque.

  The auxiliary assist current determining process 50b is a process of differentiating the output signal of the torque sensor 35. The auxiliary assist current adding process 50c is a value of the output signal of the torque sensor 35 (torque sensor) differentiated by the auxiliary assist current determining process 50b. This is a process of adding the differential value of the output signal 35) to the basic assist current value. The second basic assist current value after the differential value of the output signal of the torque sensor 35 is added becomes the value of the current flowing through the electric motor 27 (assist current value). The reason why the differential value of the output signal of the torque sensor 35 is added to the first basic assist current value is as follows.

  First, as a first reason, the time from when the torque sensor 35 detects the steering torque until the assist force is transmitted to the worm wheel 26 via the worm gear 25 (hereinafter referred to as “delay time”). The point is aimed at shortening. That is, the purpose is to improve assist responsiveness. Therefore, even when the steering torque detected by the torque sensor 35 changes suddenly (changes suddenly), the steering force can be assisted with the assist force corresponding to the suddenly changed steering torque.

  The second reason is that the purpose is to prevent the first basic assist current value from oscillating. Oscillation occurs when the gain is 1 (0 dB) and the phase is inverted by 180 degrees. For this reason, by differentiating, the phase is advanced 90 degrees to prevent oscillation.

  The drive circuit 40 drives the electric motor 27 according to the second basic assist current value, holds the current value flowing through the electric motor 27 constant, and the current flowing through the electric motor 27 at the assist current value. A feedback process 40a for feeding back the value of is provided.

  In the present invention, the steering characteristic (steering torque-assist current characteristic) of a small boat having one outboard motor is stored in the basic assist current determination processing 50a, and the small boat having only one outboard motor is stored. And the first basic assist current value is determined. FIG. 12 shows an example of steering characteristics in the case of one outboard motor. In a small vessel having only one outboard motor, as described above, the steering force is generated in the handle by the rotation of the screw, and the small vessel tries to turn according to the rotation direction of the screw. For this reason, the driver needs to generate a steering force in the direction opposite to the turning direction of the small vessel in order to keep the boat in a straight traveling state, and the drivability is not good.

  Therefore, in the present invention, the steering characteristic when the small ship is traveling straight is shown as a solid line in FIG. 12B, so that the steering torque generated by the screw is offset against the normal steering characteristic shown in FIG. Only the torque is offset. The offset value X is set in advance through experiments or the like. With such characteristics, an assist force in the left direction of the handle is generated from the electric motor 27 to the handle 2 so as to cancel the steering force in the right direction of the handle due to the rotational force of the screw when the handle is neutral. For example, when the screw rotation direction is clockwise when viewed from the rear of the small ship, the small ship will turn right, so that it generates an assist force to steer to turn left when the handle is neutral, A small ship can go straight ahead. Further, since it can be considered that the steering force due to the rotation of the screw is always acting during the rotation of the screw, it is desirable that the characteristics always take into account the steering force of the screw as shown in the figure.

  Further, as a steering characteristic corresponding to the steering force of the screw, in addition to the characteristic indicated by the solid line in FIG. 12B, a characteristic (indicated by a one-dot chain line) that improves the steering feeling by eliminating the constant region of the assist current with respect to the torque fluctuation. ) Or a characteristic (indicated by a broken line) obtained by offsetting the assist current of the characteristic (a).

  Next, the content of this control implemented by ECU is demonstrated using the flowchart of FIG. In this flowchart, the control using the conventional characteristic shown in FIG.

First during forward in step S1 (where the handle is let go from the straight state, the handle free state without the steering to maintain a straight) the hand from the handle in the output voltage read E (straight state of the torque sensor 35 The voltage when released is used as the reference value). In the case of a small vessel equipped with one outboard motor, the small vessel turns to the right, for example, due to the influence of the screw rotation described above when traveling straight ahead. For this reason, the output value of the torque sensor 35 does not indicate a reference value indicating that the vehicle is traveling straight, but outputs torque to the right. In the subsequent step S2, an offset voltage Xe that generates torque for assisting steering to the left side to cancel the torque to the right side is added to the read voltage value E to obtain a new output voltage E. In step S3, the steering torque is calculated from the calculated voltage value E, an assist current value I for canceling the turning by the screw is obtained from the steering torque, and the electric motor is operated based on the assist current value I to operate the steering wheel assist. Gain power. Here, the offset voltage Xe may be set to a constant value through experiments or the like in advance. Further, instead of the offset voltage Xe in step 2, a predetermined offset torque may be added in step 3.

Note that the offset voltage Xe may be changed according to the speed of the small vessel (= the number of rotations of the screw). In this case, it is possible to ensure the straightness of the small vessel with higher accuracy. Further, the steering torque in the straight traveling state may be calculated in advance, the difference from the torque by the screw in step S1 may be obtained, and assist torque that cancels out this torque difference may be generated.

  FIG. 14 is another example of a block diagram showing a controller of the electric motor 27 of FIG. Hereinafter, the process performed by ECU is demonstrated in detail. The processes executed in the ECU 3 mainly include a basic assist current determination process 50a, auxiliary assist current determination processes 51 and 52, auxiliary assist current addition processes 50c and 54, and a feedback process 40a.

  The basic assist current determination process 50a is a process of determining the first basic assist current value according to the value of the output signal of the torque sensor 35, that is, the magnitude of the steering torque of the steering wheel. This basic assist current determination processing 50a is performed by using an assist current value corresponding to the magnitude of the steering torque (the output signal value of the torque sensor 35) from data stored in advance in an EEPROM, CPU flash memory, or program data area. Is a process for determining the data relating to the first basic assist current value. As shown in FIG. 15, the first basic assist current value has a slight dead zone with respect to the output of the torque sensor 35 and is approximately proportional to the square of the value of the output signal of the torque sensor 35. .

  FIG. 15 shows three characteristics in which the magnitudes of the steering torque and the assist current are changed. This characteristic is not limited to three characteristics, but may be at least two characteristics. The characteristic of changing the magnitude of the assist current can be selected by a changeover switch 49 (such as a rotary switch or a toggle switch) provided in the vicinity of the steering handle 2. Further, this characteristic can be set according to the preference of the steering wheel by the size of the steering diameter of the ship, the size of the engine output, the ship speed, and the like.

  The auxiliary assist current determining process 51 is a process for differentiating the output signal of the torque sensor 35 to correct the cogging torque peculiar to the electric motor 27. The auxiliary assist current adding process 50 c is differentiated by the auxiliary assist current determining process 51. This is a process of adding the calculated value of the output signal of the torque sensor 35 to the basic assist current value. In the auxiliary assist current determination processing 51, for example, the output signal of the torque sensor 35 is digitally differentiated 51A, and the differential gain of the gain table that suppresses the vibration of the corrected output value by making it variable according to the value of the steering torque is multiplied 51B. Then, the limit 51C is applied to the excessive correction and output. The second basic assist current value after the output signals by the auxiliary assist current determination processing 51 are added becomes the basic command current value to the electric motor 27.

  The auxiliary assist current determining process 52 is a process for differentiating the output signal of the torque sensor 35 to correct the phase delay of the electric motor 27, and the auxiliary assist current adding process 54 is differentially calculated by the auxiliary assist current determining process 52. In this process, the value of the output signal of the torque sensor 35 is added to the assist command current value at the final stage. In this auxiliary assist current determination processing 52, for example, the output signal of the torque sensor 35 is subjected to an analog differentiation 52A by an analog differentiator having high responsiveness and resolution, and the vibration of the corrected output value is varied by changing the steering torque value. The differential gain of the gain table to be suppressed is multiplied by 52B and output with the phase delay correction and change amount correction limit 52C. The assist current value after the output signals of the auxiliary assist current determination process 52 are added becomes the final command current value to the driver PWM that drives the electric motor 27, and the electric motor 27 is driven via the PWM.

  The reason why the differential value of the output signal of the torque sensor 35 is added to the first basic assist current value and the reason why it is added to the final assist current value is as follows.

  First, as a first reason, the time from when the torque sensor 35 detects the steering torque until the assist force is transmitted to the worm wheel 26 via the worm gear 25 (hereinafter referred to as “delay time”). The point is aimed at shortening. That is, the object is to improve assist responsiveness. Therefore, even when the steering torque detected by the torque sensor 35 changes suddenly (changes suddenly), the steering force can be assisted with the assist force corresponding to the suddenly changed steering torque.

  The second reason is that the purpose is to prevent the assist current value from oscillating. By differentiating, the phase can be advanced by 90 degrees to prevent oscillation.

  The feedback process 40a is a process for making the current value flowing through the electric motor 27 coincide with the assist current command value. When the electric motor 27 rotates, the electric motor 27 generates electric power in the same manner as the generator to generate a counter electromotive voltage, and the current value flowing through the electric motor 27 is reduced. For this reason, the steering force is assisted with an assist force smaller than the assist force corresponding to the steering torque, and the feeling becomes worse. In order to prevent this phenomenon, the current value flowing through the electric motor 27 is fed back and subtracted from the assist current command value to perform processing for making the motor current value coincide with the assist current command value.

  Therefore, in the present invention, the influence of the steering force on the steering wheel steering due to the rotational force of the screw is canceled by generating the assist force in the opposite direction to the steering force of the screw by the assist means (electric motor). It is possible to improve the straightness of the.

  The present invention is a power steering device capable of improving straight traveling performance, and is useful for a small boat provided with one outboard motor.

The perspective view of the power steering device for small ships which shows one Embodiment of this invention. The side view which similarly shows an outboard motor. The top view of a link mechanism similarly. The top view of the gear apparatus and power assist apparatus of a power steering apparatus. The side view of the gear apparatus and power assist apparatus of a power steering apparatus. The side view from the handle | steering-wheel side of the gear apparatus and power assist apparatus of a power steering apparatus. The side view by the side of the gear apparatus of the gear apparatus of a power steering apparatus and a power assist apparatus. Sectional drawing of the gear apparatus and power assist apparatus of a power steering apparatus. Sectional drawing of the power assist apparatus of a power steering apparatus. The block diagram which showed the control system of the electric motor. The characteristic view which shows the assist characteristic by a basic assist electric current value. The steering characteristic figure applied to the small ship provided with the 1 outboard motor of this invention. The flowchart applied to the small ship provided with one outboard motor. The other block diagram which showed the control system of the electric motor. The characteristic view which shows the assist characteristic by a basic assist electric current value.

Explanation of symbols

1 Hull 2 Steering handle 3 Push-pull cable (connection means)
4, 4A gear device 5 power assist device 6 outboard motor 7 link mechanism 20 rack 21 pinion 22 output shaft 23 steering shaft 24 torsion bar 25 worm gear 26 worm wheel 27 electric motor (electric actuator)
30 Torque ring 35 Torque sensor

Claims (3)

An outboard motor body disposed at the rear of the hull so as to be turnable in the left-right direction with respect to the hull;
A steering mechanism for rotating the outboard motor according to a steering operation of a steering handle of a driver seat;
A torque sensor for detecting a steering torque of the steering handle;
Assist means for power assisting the steering mechanism in a steering operation direction according to at least a detection signal of a torque sensor;
In a power steering device for a small ship, comprising a controller that takes in a detection signal of the torque sensor, calculates and outputs a current for driving the assist means,
The torque sensor detects a torque in a state where a hand is released from the steering handle straight running state and the steering wheel is not operated to maintain the straight running when the small boat is traveling.
The controller corrects the steering torque by adding a predetermined value so as to cancel the detected torque, and outputs a current to the assist means so as to generate the corrected steering torque. Steering device. An outboard motor body disposed at the rear of the hull so as to be turnable in the left-right direction with respect to the hull;
A steering mechanism for rotating the outboard motor according to a steering operation of a steering handle of a driver seat;
A torque sensor for detecting a steering torque of the steering handle;
Assist means for power assisting the steering mechanism in a steering operation direction according to at least a detection signal of a torque sensor;
In a power steering device for a small ship, comprising a controller that takes in a detection signal of the torque sensor, calculates and outputs a current for driving the assist means,
The torque sensor detects a steering torque in the straight traveling state of the steering wheel and a torque when a hand is released from the straight traveling state when traveling on a small ship,
The controller obtains a difference between the steering torque detected by the torque sensor and the torque, and outputs a current to the assist means so as to cancel the torque difference. apparatus.   The power steering device for a small boat according to claim 1 or 2, wherein the assist force of the steering mechanism is set according to the number of rotations of the screw.

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