Steering handle of outboard motor

A tiller handle includes: a throttle shaft including first shaft and the second shaft; a conversion mechanism configured to convert rotation of the first shaft into a rectilinear motion of the throttle cable; an engagement pin provided in the second shaft; and a restriction member (shift arm) engaged with the engagement pin depending on a position of a selector in synchronization with the selector to restrict rotation of the second shaft in a throttle valve open direction. The first shaft and the second shaft are configured to relatively rotate each other only by a predetermined angle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-115217, filed on Jun. 12, 2017, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a steering handle of an outboard motor provided with a throttle manipulator and a gearshift manipulator.

Description of the Related Art

In many cases, an outboard motor mounted on a ship has a steering handle for allowing an operator to perform steering. In addition, the steering handle is configured to allow a throttle manipulation or a gearshift manipulation in some cases.

For example, Patent Document 1 discusses a steering handle of an outboard motor provided with a throttle grip and a gearshift handle. If a throttle opening level increases while a gear position is neutral, that is, while an engine receives no load, an engine rotation number extremely increases, and this generates various problems. In order to avoid such problems, Patent Document 1 discusses a throttle opening level restriction mechanism for restricting a throttle manipulation while the gear position is neutral.Patent Document 1: Japanese Laid-open Patent Publication No. 7-81689

In some cases, it is desirable to slightly open a throttle valve, for example, for a warm-up operation while the gear position is neutral. However, a throttle manipulation for the warm-up operation is also restricted by the throttle opening level restriction mechanism.

In the case of the throttle opening level restriction mechanism, if a throttle grip is rotated, for example, due to an erroneous manipulation or the like while the gear position is neutral, a distortion is generated in a throttle shaft connected to the throttle grip because it receives both a rotation force from the throttle grip and a restriction force from the throttle opening level restriction mechanism. If a distortion is generated in the throttle shaft, meshing accuracy of a gear that converts rotation of the throttle shaft into a rectilinear motion of a throttle cable is degraded. This may generate problems such as degradation of a subsequent steering feeling.

SUMMARY OF THE INVENTION

In view of the aforementioned problems, it is therefore an object of the present invention to allow a predetermined necessary throttle manipulation even when the gearshift manipulator is in the throttle manipulation restriction position by restricting a throttle manipulation depending on a position of the gearshift manipulator and to prevent degradation of a steering feeling.

According to an aspect of the present invention, there is provided a steering handle of an outboard motor, including: a throttle manipulator configured to perform a throttle manipulation for adjusting opening and closing a throttle valve; a gearshift manipulator configured to perform a gearshift manipulation for shifting a gear position of the outboard motor; a throttle shaft having a first shaft connected to the throttle manipulator to rotate around its center axis in response to a manipulation of the throttle manipulator and a second shaft arranged coaxially with the first shaft to rotate in synchronization with the first shaft; a conversion mechanism that converts rotation of the first shaft into a rectilinear motion of a throttle cable; an engagement portion provided in the second shaft; and a restriction member engaged with the engagement portion depending on a position of the gearshift manipulator in synchronization with the gearshift manipulator to restrict rotation of the second shaft in a throttle valve open direction, wherein the first shaft and the second shaft are configured to relatively rotate each other only by a predetermined angle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A steering handle of an outboard motor according to an embodiment of the invention includes a throttle manipulator configured to perform a throttle manipulation for adjusting opening and closing a throttle valve, a gearshift manipulator configured to perform a gearshift manipulation for shifting a gear position of the outboard motor, a throttle shaft having a first shaft connected to the throttle manipulator to rotate around its center axis in response to a manipulation of the throttle manipulator and a second shaft arranged coaxially with the first shaft to rotate in synchronization with the first shaft, a conversion mechanism that converts rotation of the first shaft into a rectilinear motion of a throttle cable, an engagement portion provided in the second shaft, and a restriction member engaged with the engagement portion depending on a position of the gearshift manipulator in synchronization with the gearshift manipulator to restrict rotation of the second shaft in a throttle valve open direction, wherein the first shaft and the second shaft are configured to relatively rotate each other only by a predetermined angle.

In the steering handle of the outboard motor configured as described above, even when the gearshift manipulator is in the throttle manipulation restriction position, the first shaft can rotate by manipulating the throttle manipulator in a throttle valve opening direction as long as the relative rotation between the first shaft and the second shaft is allowed. Since rotation of the first shaft is converted into a rectilinear motion of the throttle cable using the conversion mechanism, it is possible to open the throttle valve. Therefore, even when the gearshift manipulator is in the throttle manipulation restriction position by restricting the throttle manipulation depending on a position of the gearshift manipulator, it is possible to perform a predetermined necessary throttle manipulation (for example, a throttle manipulation for a warm-up operation) and prevent a distortion of the throttle shaft. Therefore, it is possible to prevent degradation of a steering feeling.

Embodiment

A preferable embodiment of the invention will now be described with reference to the accompanying drawings.

First, an exemplary outboard motor according to the invention will be described.FIG. 1is a right side view illustrating the outboard motor1. Herein, directions such as the upper, lower, left, right, front, and rear directions are illustrated by assuming that the outboard motor1is mounted on a ship hull2, and they are referred to in each drawing as necessary.

The outboard motor1has an engine holder3, and an engine4such as an internal combustion engine is mounted in the upper side of the engine holder3. The engine4is, for example, a water-cooled four-cycle two-cylinder engine and also a vertical type engine in which its crankshaft5is arranged substantially vertically. An output power control of the engine4is performed by adjusting an intake air amount by opening or closing a throttle valve6or the like. The open/close adjustment of the throttle valve6is controlled using a throttle cable105described below in response to a manipulation of the throttle grip101of the tiller handle100. The engine4is covered by an engine cover7.

A drive shaft8vertically arranged is coupled to the lower end of the crankshaft5. The drive shaft8is housed in a drive shaft housing9and extends to a gear casing10provided in a lower end of the drive shaft housing9. A bevel gear11, a front gear12, a rear gear13, and a propeller shaft14are arranged in the gear casing10. The bevel gear11is coupled to a lower end of the drive shaft8, and the front and rear gears12and13are arranged on an axis of the propeller shaft14. Rotation of the drive shaft is transmitted from the bevel gear11to the propeller shaft14through the front or rear gear12or13. A propeller15rotating in synchronization with the propeller shaft14is coupled to a rear end of the propeller shaft14.

A shift rod16is arranged substantially vertically in front of the drive shaft housing9. The shift rod16is actuated using a shift cable110described below in response to a manipulation on the selector102of the tiller handle100. As the shift rod16is actuated, a gear position can be shifted to a forward or reverse position by switching a gear used to transmit power from the bevel gear11to the propeller shaft14between the front and rear gears12and13using a cam mechanism and a dog clutch (not shown) arranged in the gear casing10.

The outboard motor is mounted on a transom board2aof the ship hull2using a mount portion17. The mount portion17has a pair of left and right clamp brackets18and a swivel bracket19. The clamp brackets18are fixed to the transom board2ain a tail end of the ship hull2. The swivel bracket19is supported rotatably in a vertical direction by a tilt shaft20provided between a pair of left and right clamp brackets18. A pilot shaft (not shown) is supported rotatably in a left-right direction by the swivel bracket19. An upper mount bracket21and a lower mount bracket22are provided in upper and lower ends of the pilot shaft. The upper mount bracket21and the lower mount bracket22are coupled to the drive shaft housing9.

The upper mount bracket21is provided with a handle bracket23, and the tiller handle100is installed substantially along a horizontal direction by inserting a pivot shaft24. The tiller handle100can be rotated around the pivot shaft24from a use state in which it extends to the front side substantially in the horizontal direction to a storage state in which it is erected substantially vertically (refer to the two-dotted chain line ofFIG. 1).

The tiller handle100is used to allow an operator to change a steering angle of the outboard motor1. As an operator turns the tiller handle100in the horizontal direction, the drive shaft housing turns with respect to an axial line C of the pilot shaft using the upper mount bracket21and the lower mount bracket22. That is, the entire outboard motor turns in response to steering using the tiller handle100to change a travel direction of the ship hull2.

The tiller handle100as a steering handle of the outboard motor will now be described in more details with reference toFIGS. 2 to 6B. Note that the directions described below refer to directions while the tiller handle100has a use state.

The tiller handle100is also called a bar handle and has a long handle body103. The handle body103is formed of resin or the like, so that accessories can be mounted inside.

A throttle grip101is rotatably installed in one end of the handle body103(which is an end of a direction protruding from the outboard motor1). The throttle grip101has a cylindrical shape extending in the front-rear direction in order to allow an operator to grip it easily, and is supported rotatably around its center line. The throttle grip101is a throttle manipulator for performing a throttle manipulation for adjusting an open/close operation of the throttle valve6. Typically, the throttle grip101is set in a full-close position in which the throttle valve opening level is set to a minimum opening level. If the throttle grip101is rotated counterclockwise as seen from the ship hull2side, the throttle valve is manipulated in an open direction.

The selector102is installed in a substantially center of the front-rear direction on the right side surface of the handle body103tiltably to the front or rear direction. The selector102is a gearshift manipulator for performing a gearshift manipulation for shifting the gear position of the outboard motor1. As illustrated in the arrow ofFIG. 2, a gearshift manipulation to the forward position F is performed by tilting the selector102to the front direction from the neutral position. In addition, a gearshift manipulation to the reverse position R is performed by tilting it from the neutral position to the rear direction.

Inside the handle body103, a throttle shaft104extending in the front-rear direction is connected to the throttle grip101and is arranged so as to rotate around its center axis in response to a manipulation of the throttle grip101. The throttle shaft104includes a first shaft104aconnected to the throttle grip101so as to rotate around its center axis in response to a manipulation on the throttle grip101, and a second shaft104barranged coaxially with the first shaft104aso as to rotate along with the first shaft104a.

A conversion mechanism106that converts rotation of the first shaft104ainto a rectilinear motion of the throttle cable105is linked to the first shaft104a. The conversion mechanism106has a bevel gear107provided in the first shaft104aand a gear108that is supported by the handle body103and meshes with the bevel gear107. The throttle cable105is connected to an arm108aextending downward from the gear108. As the gear108is rotated through the bevel gear107in synchronization with rotation of the first shaft104a, the arm108ais tilted in the front or rear direction so that the throttle cable105makes a rectilinear motion (push-pull motion). The throttle cable105is mechanically linked to the throttle valve6of the outboard motor1so that the throttle valve6is adjusted for opening or closing in response to the push-pull motion. Any one of those well known in the art may be employed as this link mechanism, and it will not be described here for simplicity purposes.

Inside the handle body103, a shift arm109tilted to the front or rear direction in synchronization with the selector102is arranged, and the shift cable110is connected to an upper part of the shift arm109. As the shift arm109is tilted to the front or rear direction in synchronization with the selector102, the shift cable110makes a rectilinear motion (push-pull motion). The shift cable110is mechanically linked to the shift rod16of the outboard motor1, and the shift rod16is actuated in response to the push-pull motion of the shift cable110. Any one of those well known in the art may be employed as this link mechanism, and it will not be described herein for simplicity purposes. Note that a detent mechanism111is provided under the shift arm109to hold forward, neutral, and reverse positions of the selector102and apply resistance to a gearshift manipulation.

Here, the second shaft104bis provided with an engagement pin112as the engagement portion. As illustrated inFIG. 4, the engagement pin112has a bar portion112aprovided in the second shaft104bso as to protrude in a radial direction of the second shaft104b, and a roller112brotatably installed in the bar portion112a.

The shift arm109functions as a restriction member for restricting rotation of the second shaft104bin the throttle valve open direction as it is engaged with the engagement pin112depending on a position of the selector102.

Specifically, as illustrated inFIGS. 2 to 4 and 5A, when the shift arm109is in a neutral position in synchronization with the selector102, the engagement pin112abuts on a restriction surface109aof the shift arm109so as to restrict rotation of the second shaft104bin the throttle valve open direction. As a result, a throttle manipulation for manipulating the throttle grip101in the throttle valve open direction is restricted.

Meanwhile, as illustrated inFIG. 5B, when the selector102is in a forward or reverse position, the shift arm109is tilted so that the restriction surface109adeviates from the position of the engagement pin112. Therefore, the second shaft104bcan rotate in the throttle valve open direction without a restriction. As a result, it is possible to freely manipulate the throttle grip101in the throttle valve open direction.

According to this embodiment, when the selector102is in the forward or reverse position, and the throttle grip101is manipulated in the throttle valve open direction over a predetermined manipulation range (a predetermined rotation angle from a full-close position), the engagement pin112is located in the lateral side of the shift arm109. In this state, even when an operator tries to return the selector102to the neutral position, a gearshift manipulation for returning to the neutral position is restricted because the shift arm109interferes with the engagement pin112. In other words, in order to return the selector102to the neutral position, it is necessary to first return the throttle grip101to the throttle valve close direction.

According to this embodiment, when the selector102is in a forward or reverse position, and the throttle grip101is not greatly manipulated in the throttle valve open direction, the throttle grip101can forcibly return to the throttle valve close direction in synchronization with a gearshift manipulation for returning the selector102to the neutral position. Specifically, the shift arm109is provided with a guide surface109bhaving a sloped surface shape continuous to both sides of the restriction surface109aas a guide portion. When the selector102is in a forward or reverse position, and the throttle grip101is manipulated within a predetermined manipulation range (a predetermined rotation angle from the full-close position), the engagement pin112abuts on the guide surface109bin response to a gearshift manipulation for returning the selector102to the neutral position. In addition, as the selector102returns to the neutral position, the engagement pin112is guided by the guide surface109b, and the second shaft104bis rotated in the throttle valve close direction. In this case, the roller112brolls on the guide surface109b, so that it is possible to smoothly move the engagement pin112along the guide surface109b. In addition, as the selector102returns to the neutral position, the engagement pin112returns to a state in which it abuts on the restriction surface109aof the shift arm109as illustrated inFIG. 5A.

FIGS. 6A and 6Billustrate an exemplary configuration of a surrounding structure of a connecting portion between the first shaft104aand the second shaft104b. As described above, the throttle shaft104includes the first shaft104aand the second shaft104b, and the first shaft104aand the second shaft104bare connected to each other through a cylindrical joint113.

The first shaft104ais inserted into one end of the joint113, and the first shaft104aand the joint113are fixed using the pin114to rotate in synchronization. Meanwhile, the second shaft104bis inserted into the other end of the joint113. The joint113is provided with an opening115, and the pin116erected on the second shaft104bis inserted into this opening115. The opening115is set to be large in the rotation direction of the throttle shaft104, compared to the pin116. As a result, the second shaft104band the joint113(that is, the first shaft104a) can relatively rotate until the pin116abuts on the edge of the opening115.

A return spring117is provided as a biasing member for applying a biasing force to the first shaft104ain the throttle valve close direction. The return spring117consists of a coil spring installed around the second shaft104band has one end linked to a flange113aprovided in the joint113and the other end locked with the engagement pin112. By applying the biasing force to the first shaft104ain the throttle valve close direction using the return spring117, it is possible to maintain the throttle grip101in the full-close position using the first shaft104aas illustrated inFIG. 6Aand suppress wobbling between the first shaft104aand the second shaft104b.

As illustrated inFIGS. 1 and 2, inside the handle body103, the throttle shaft104is rotatably supported by the bearings118and119. Specifically, the first shaft104ais rotatably supported by the bearing118in a portion closer to the second shaft104b, compared to the bevel gear107of the conversion mechanism106. In addition, the second shaft104bis rotatably supported by the bearing119in a portion closer to the end of the outboard motor side (in a portion opposite to the throttle grip101), compared to the engagement pin112.

In the tiller handle100configured as described above, when the selector102is in the neutral position, the engagement pin112abuts on the restriction surface109aof the shift arm109so as to restrict rotation of the second shaft104bin the throttle valve open direction.

However, a throttle manipulation within a small throttle opening level is allowed even when the selector102is in the neutral position. Specifically, as illustrated inFIGS. 6A and 6B, the engagement pin112abuts on the restriction surface109aof the shift arm109, so that rotation of the second shaft104bin the throttle valve open direction is restricted. However, the first shaft104aand the second shaft104bcan relatively rotate only by a predetermined angle. Within this range, it is possible to rotate the first shaft104aresisting to a biasing force of the return spring117by manipulating the throttle grip101in the throttle valve open direction. Since rotation of the first shaft104ais converted into a rectilinear motion of the throttle cable105using the conversion mechanism106, it is possible to open the throttle valve6, for example, in order to perform a warm-up operation. Note that, when an operator releases a hand from the throttle grip101, the throttle grip101returns to the full-close position by virtue of the biasing force of the return spring117.

When the selector102is in the neutral position, and the throttle grip starts to rotate, for example, due to an erroneous manipulation or the like, the first shaft104aand the second shaft104brelatively rotate, so that it is possible to prevent a distortion of the throttle shaft104. Therefore, it is possible to prevent degradation of meshing accuracy of the bevel gear107or the gear108included in the conversion mechanism106and degradation of a steering feeling.

While embodiments of the invention have been described in details hereinbefore with reference to the accompanying drawings, it should be noted that the aforementioned embodiments merely illustrate concrete examples of implementing the present invention, and the technical scope of the present invention is not to be construed in a restrictive manner by these embodiments. That is, the present invention may be implemented in various forms without departing from the technical spirit or main features thereof, and they are also included in the technical scope of the invention.

For example, although a push-pull type throttle manipulation and gearshift manipulation is performed by way of example in the aforementioned embodiment, for example, a pull-pull type may also be employed.

According to the present invention, it is possible to allow a predetermined necessary throttle manipulation even when the gearshift manipulator is in the throttle manipulation restriction position by restricting a throttle manipulation depending on a position of the gearshift manipulator and to prevent degradation of a steering feeling.