Patent Publication Number: US-7217167-B2

Title: Outboard motor shift device

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to an outboard motor shift device. 
   2. Description of the Related Art 
   Japanese Laid-Open Patent Application No. 2004-245350 (particularly paragraphs 0048 to 0050 and FIGS. 10 and 11), for example, teaches a shift device that changes the gear position of an outboard motor by using an actuator to drive a shift rod that operates a clutch. 
   In the technique taught by this reference, the reduction gear mechanism for transmitting the output of the actuator to the shift rod is equipped with a manually operable emergency gear to be used in case of failure of the actuator or its control system. The reliability of the system is therefore enhanced because even if driving of the shift rod by the actuator should become impossible, the operator can still shift the outboard motor by manually rotating the emergency gear which in turn rotates the shift rod through the reduction gear mechanism. 
   When the operator&#39;s rotation of the emergency gear is transmitted to the shift rod, it is also simultaneously transmitted to the actuator. In the prior art, therefore, the operation load experienced by the operator when turning the emergency gear, i.e., when manually operating the shift rod, is large. 
   SUMMARY OF THE INVENTION 
   An object of this invention is therefore to overcome this drawback and to provide an outboard motor shift device that enhances reliability by enabling shifting both by the actuator and manually which minimizes operation load during manual shifting. 
   In order to achieve the object, this invention provides a device for shifting a gear of an outboard motor adapted to be mounted on a stern of a boat among a forward position, a reverse position and a neutral position such that the boat may be propelled in a direction determined by the gear position, comprising: a clutch being engageable with a forward gear or a reverse gear; a shift rod rotatable to slide the clutch to engage with the gears; an actuator connected to rotate the shift rod; a speed reduction gear mechanism transmitting an output of the actuator to the shift rod at a reduced speed; and a manual operation mechanism manually operable by an operator to break an output transmission train of the speed reduction gear mechanism such that the shift rod can be manually rotated by the operator. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and advantages of the invention will be more apparent from the following description and drawings in which: 
       FIG. 1  is an overall schematic view of an outboard motor shift device, as mounted on a boat (hull), according to an embodiment of the invention; 
       FIG. 2  is a side view of the outboard motor shown in  FIG. 1 ; 
       FIG. 3  is a partial sectional side view of the outboard motor shown in  FIG. 1 ; 
       FIG. 4  is an enlarged, partially see-through, plan view showing the region of an electric shift motor shown in  FIG. 3 ; 
       FIG. 5  is a sectional view taken along line V—V in  FIG. 4 ; 
       FIG. 6  is a sectional view taken along line VI—VI in  FIG. 5 ; 
       FIG. 7  is an enlarged sectional view taken along line VII—VII in  FIG. 5 ; 
       FIG. 8  is a sectional view similar to  FIG. 5 ; 
       FIG. 9  is a sectional view similar to  FIG. 5 ; 
       FIG. 10  is a sectional view taken along line X—X in  FIG. 9 ; and 
       FIG. 11  is an enlarged sectional view taken along line XI—XI in  FIG. 9 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of an outboard motor shift device according to the present invention will now be explained with reference to the attached drawings. 
     FIG. 1  is an overall schematic view of an outboard motor shift device as mounted on a boat (hull), according to an embodiment of the invention and  FIG. 2  is a side view of the outboard motor shown in  FIG. 1 . 
   In  FIGS. 1 and 2 , the symbol  10  indicates an outboard motor. The outboard motor  10  is mounted on the stern (transom) of a boat (hull)  12 . As shown in  FIG. 1 , a steering wheel  16  is installed near a cockpit (the operator&#39;s seat)  14  of the boat  12 . A steering angle sensor  18  is installed near a rotary shaft (not shown) of the steering wheel  16  and produces an output or a signal indicative of the steering angle (manipulated variable) of the steering wheel  16  manipulated by the operator. 
   A remote control box  20  is installed near the cockpit  14 . The remote control box  20  is installed or provided with a lever  22  that is to be manipulated by the operator. The lever  22  is free to be rotated fore and aft (toward and away from the operator) from the initial position, and is positioned to be manipulated by the operator to input an instruction to shift or to regulate a speed of an internal combustion engine. 
   The remote control box  20  is equipped with a lever position sensor  24  that produces an output or a signal corresponding to a position to which the lever  22  is manipulated by the operator. The outputs from the steering angle sensor  18  and lever position sensor  24  are sent to an electronic control unit (hereinafter referred to as “ECU”)  26  mounted on the outboard motor  10 . The ECU  26  comprises a microcomputer. 
   As shown in  FIG. 2 , the outboard motor  10  is equipped with the internal combustion engine (now assigned with symbol  28 ; hereinafter referred to as “engine”) at its upper portion. The engine  28  comprises a spark-ignition gasoline engine. The engine  28  is located above the water surface and covered by an engine cover  30 . The ECU  26  is installed in the engine cover  30  at a location near the engine  28 . 
   The outboard motor  10  is equipped at its lower portion with a propeller  32 . The output of the engine  28  is transmitted to the propeller  32  through a shift mechanism (described below) and the like, such that the propeller  32  is rotated to generate thrust that propels the boat  12  in the forward and reverse directions. 
   The outboard motor  10  is further equipped with an electric steering motor (steering actuator)  34  that steers the outboard motor  10  to the right and left directions, an electric throttle motor (throttle actuator)  36  that opens and closes a throttle valve (not shown in  FIG. 2 ) of the engine  28  and an electric shift motor (shift actuator)  38  that operates the shift mechanism (described below) by rotating a shift rod (not shown in  FIG. 2 ) to change a gear position. 
   A gear position sensor  40  and neutral switch  42  are installed near the shift motor  38 . The gear position sensor  40  produces an output or a signal in response to a gear position. The neutral switch  42  produces an ON signal when the neutral (gear) position is established and an OFF signal when the forward or reverse gear position is established. The outputs from the gear position sensor  40  and neutral switch  42  are sent to the ECU  26 . 
   The ECU  26  generates an output indicative of a permission to start the operation of the engine  28  only when the neutral switch  42  outputs the ON signal, i.e., when it is detected that the gear is at the neutral position, so as to prevent the boat  12  from moving at the engine start. 
   The ECU  26  controls the operation of the steering motor  34  based on the output of the steering angle sensor  18  to steer the outboard motor  10  left and right. The ECU  26  also changes or shifts the gear position, i.e., conducts the gear change by controlling the operation of the shift motor  38  based on the manipulated angle of the lever  22  (more exactly, the manipulated direction of the lever  22 ) detected by the lever position sensor  24 . When the establishment of either the forward or reverse gear position is detected from the output of the gear position sensor  40 , the ECU  26  controls the operation of the throttle motor  36  based on the manipulated angle (more exactly, the magnitude of the manipulated variable) of the lever  22  to regulate the engine speed. 
   The structure of the outboard motor  10  will then be described in detail with reference to  FIG. 3 .  FIG. 3  is a partial sectional view of the outboard motor  10 . 
   As shown in  FIG. 3 , the outboard motor  10  is equipped with stern brackets  50  fastened to the stern of the boat  12 , such that the outboard motor  10  is mounted on the stern of the boat  12  through the stern brackets  50 . A swivel case  54  is attached to the stern brackets  50  through a tilting shaft  52 . 
   The outboard motor  10  is also equipped with a mount frame  56  having a shaft  58 . The shaft  58  is housed in the swivel case  54  to be freely rotated about a vertical axis. The upper end of the mount frame  56  is fastened to a frame of the outboard motor  10  and the lower end thereof is fastened to the frame through a lower mount center housing  60 . 
   The upper portion of the swivel case  54  is installed with the steering motor  34 . The output shaft of the steering motor  34  is connected to the mount frame  56  via a speed reduction gear mechanism  64 . Specifically, a rotational output generated by driving the steering motor  34  is transmitted via the speed reduction gear mechanism  64  to the mount frame  56  such that the outboard motor  10  is steered about the shaft  58  as a rotational axis to the right and left directions (i.e., steered about the vertical axis). 
   The engine  28  has an intake pipe  70  that is connected to a throttle body  72 . The throttle body  72  has a throttle valve  74  installed therein and the throttle motor  36  is integrally disposed thereto. The output shaft of the throttle motor  36  is connected via a speed reduction gear mechanism (not shown) installed near the throttle body  72  with a throttle shaft  76  that supports the throttle valve  74 . Specifically, a rotational output generated by driving the throttle motor  36  is transmitted to the throttle shaft  76  to open and close the throttle valve  74 , thereby regulating air sucked in the engine  28  to change the engine speed. 
   An extension case  80  is installed at the lower portion of the engine cover  30  that covers the engine  28  and a gear case  82  is installed at the lower portion of the extension case  80 . A drive shaft (vertical shaft)  84  is supported in the extension case  80  and gear case  82  to be freely rotated about the vertical axis. One end, i.e., the upper end of the drive shaft  84  is connected to a crankshaft (not shown) of the engine  28  and the other end, i.e., the lower end thereof is equipped with a pinion gear  86 . 
   A propeller shaft  90  is supported in the gear case  82  to be freely rotated about the horizontal axis. One end of the propeller shaft  90  extends from the gear case  82  toward the rear of the outboard motor  10  and the propeller  32  is attached thereto, i.e., the one end of the propeller shaft  90 , via a boss portion  92 . 
   As indicated by the arrows in  FIG. 3 , the exhaust gas (combusted gas) emitted from the engine  28  is discharged from an exhaust pipe  94  into the extension case  80 . The exhaust gas discharged into the extension case  80  further passes through the interior of the gear case  82  and the interior of the propeller boss portion  92  to be discharged into the water to the rear of the propeller  32 . 
   The shift mechanism (now assigned with symbol  96 ) is also housed in the gear case  82 . The shift mechanism  96  comprises a forward bevel gear  98 , reverse bevel gear  100 , clutch  102  and shift slider  104 . 
   The forward bevel gear  98  and reverse bevel gear  100  are disposed onto the outer periphery of the propeller shaft  90  to be rotatable in opposite directions by engagement with the pinion gear  86 . The clutch  102  is installed between the forward bevel gear  98  and reverse bevel gear  100  and rotates integrally with the propeller shaft  90 . 
   A shift rod  106  penetrates from the upper portion to the lower portion of the interior of the outboard motor  10 . Specifically, the shift rod  106  is supported to be freely rotated about the vertical axis in a space from the engine cover  30 , passing through the swivel case  54  (more specifically the interior of the shaft  58  accommodated therein), to the gear case  82 . The clutch  102  is connected via the shift slider  104  to a rod pin  106   a  disposed on the bottom of the shift rod  106 . 
   The rod pin  106   a  is formed at a location offset from the center of the bottom of the shift rod  106  by a predetermined distance. As a result, rotation of the shift rod  106  causes the rod pin  106   a  to move while describing an arcuate locus whose radius is the predetermined distance (offset amount). 
   The movement of the rod pin  106   a  is transferred through the shift slider  104  to the clutch  102  as displacement parallel to the axial direction of the propeller shaft  90 . As a result, the clutch  102  is slid to a position where it engages one or the other of the forward bevel gear  98  and reverse bevel gear  100  or to a position where it engages neither of them. 
   When the clutch  102  is engaged with the forward bevel gear  98 , the rotation of the drive shaft  84  is transmitted through the pinion gear  86  and forward bevel gear  98  to the propeller shaft  90 , thereby rotating the propeller  32  to produce thrust in the direction of propelling the boat  12  forward. Thus the forward gear position is established. 
   When the clutch  102  is engaged with the reverse bevel gear  100 , the rotation of the drive shaft  84  is transmitted through the pinion gear  86  and reverse bevel gear  100  to the propeller shaft  90 , thereby rotating the propeller  32  in the direction opposite from that during forward travel to produce thrust in the direction of propelling the boat  12  rearward. Thus the reverse gear position is established. 
   When the clutch  102  is not engaged with either the forward bevel gear  98  or the reverse bevel gear  100 , the rotation of the drive shaft  84  is not transmitted to the propeller shaft  90 . Thus the neutral position is established. 
   The explanation of  FIG. 3  will be resumed. The shift motor  38  is installed inside the engine cover  30  and its output shaft is connected to the upper end of the shift rod  106  through a speed reduction gear mechanism  110 . Therefore, when the shift motor  38  is driven, its rotational output is transmitted to the shift rod  106  through the speed reduction gear mechanism  110 , thereby rotating the shift rod  106 . The shift mechanism  96  is operated (specifically, the clutch  102  is slid) in response to the rotation of the shift rod  106  so as to select a gear position from among the foregoing forward, neutral and reverse positions. 
     FIG. 4  is an enlarged, partially see-through, plan view showing the region of the shift motor  38 .  FIG. 5  is a sectional view taken along line V–V in  FIG. 4 . 
   As shown in  FIGS. 4 and 5 , the output shaft  38   a  of the shift motor  38  is connected to the upper end of the shift rod  106  through the reduction gear mechanism  110 . The reduction gear mechanism  110  is a multi-gear mechanism comprising first to ninth gears  110   a  to  110   i.    
   The first gear  110   a  is provided on the shift motor output shaft  38   a  and meshes with the second gear  110   b  of larger diameter. The third gear  110   c , which is smaller in diameter than the second gear  110   b , is provided on the same shaft as the second gear  110   b  and meshes with the fourth gear  110   d  of larger diameter. The fifth gear  110   e , which is smaller in diameter than the fourth gear  110   d , is provided on the same shaft as the fourth gear  110   d  and meshes with the sixth gear  110   f  of larger diameter. The sixth gear  110   f  meshes with the seventh gear  110   g  of larger diameter. 
   As shown in  FIG. 5 , the eighth gear  110   h  is provided on the same shaft as the seventh gear  110   g . The eighth gear  110   h  meshes with the ninth gear  110   i , which is provided on the upper end of the shift rod  106 . The output of the shift motor  38  is therefore transmitted to the shift rod  106  by the reduction gear mechanism  110  at reduced speed and increased torque. The aforesaid gear position sensor  40  is attached to the rotary shaft  110   j  of the seventh gear  110   g . The gear position sensor  40  outputs the rotation angle of the rotary shaft  110   j  as a signal indicating the gear position. 
   The neutral switch  42  is located above the seventh gear  110   g . As shown in  FIG. 5 , the neutral switch  42  is equipped with a detection member  42   a . A protrusion  110   k  rising from the upper surface of the seventh gear  110   g  makes contact with the detection member  42   a  of the neutral switch  42  when the gear position is neutral. When the protrusion  110   k  makes contact with the detection member  42   a , the neutral switch  42  outputs an ON signal as a signal indicating that the gear position is neutral. The outputs of the gear position sensor  40  and neutral switch  42  are sent to the ECU  26  via signal lines not shown in the drawings. 
   The sixth gear  110   f  is slidable in the tooth facewidth direction together with its rotary shaft  110   m . The sixth gear  110   f  is hereinafter referred to as a “sliding gear.” As shown in  FIG. 5 , the gears on the upstream and downstream sides of the sliding gear  110   f  in the output transmission train of the reduction gear mechanism  110  (the train from the first gear  110   a  to ninth gear  110   i ), i.e., the fifth gear  110   e  and seventh gear  110   g , are different in facewidth. Namely, the facewidth of the seventh gear  110   g  is larger than that of the fifth gear  110   e  and the difference (extra facewidth) extends upward from the level of the top surface of the fifth gear  110   e . The sliding gear  110   f  is urged downward by a spring  112 . That is, it is biased in the direction of meshing with both the fifth gear  110   e  and the seventh gear  110   g.    
   The upper segment of the rotary shaft  110   m  of the sliding gear  110   f  projects upward beyond the casing  110   n  of the reduction gear mechanism  110 , and a manual lever  120  is attached to the portion rising above the casing  110   n . The manual lever  120  is positioned so that it can be readily manipulated by the boat operator. 
   The sliding gear  110   f  and manual lever  120  constitute a manual operation mechanism for manually rotating the shift rod  106 . Here follows an explanation of the structure of the manual lever  120  and the operation of the manual operation mechanism. 
     FIG. 6  is a sectional view taken along line VI—VI in  FIG. 5 .  FIG. 7  is an enlarged sectional view taken along line VII—VII in  FIG. 5 . 
   As shown in  FIGS. 5 to 7 , the manual lever  120  is shaped substantially like a cylinder or rod. The manual lever  120  is provided with an L-shaped grooved section  120   a  formed as an indentation continuing across its bottom and side faces. More exactly, the grooved section  120   a  is composed of a groove  120   b  formed in the bottom face of the manual lever  120  and a groove  120   c  formed in the side face of the manual lever  120  to run parallel to the longitudinal direction (generating line direction) of the manual lever  120 . The rotary shaft  110   m  is inserted into the grooved section  120   a  and is connected to the manual lever  120  at its corner region (where the groove  120   b  and groove  120   c  meet at right angles) by a pin  122 . 
   This structure enables the manual lever  120  to rotate around the pin  122  by 90 degrees relative to the rotary shaft  110   m . More specifically, the manual lever  120  can be manipulated so that its longitudinal axis rotates between an upright orientation parallel to the axial direction of the rotary shaft  110   m  and a horizontal orientation perpendicular to the axial direction of rotary shaft  110   m . The manual lever  120  is shown in its horizontal orientation in  FIG. 4  discussed above. 
   The lower end of the manual lever  120  is formed with a cam member  120   d  riding on the casing  110   n  of the reduction gear mechanism  110 . The cam member  120   d  is elongated in the direction perpendicular to the longitudinal direction of the manual lever  120 , specifically in the direction away from the opening direction of the groove  120   c  (to the right in  FIG. 5 ). 
   Therefore, as shown in  FIG. 8 , when the manual lever  120  is tipped toward the elongated direction of the cam member  120   d  (to the right in  FIG. 5 ), the distance from the surface of contact between the cam member  120   d  and casing  110   n  and the pin  122  is increased. As a result, the rotary shaft  110   m  is slid upward, thereby also sliding the sliding gear  110   f  upward to disengage it from the fifth gear  110   e . This means that the output transmission train of the reduction gear mechanism  110  is broken between the sliding gear  110   f  and the fifth gear  110   e  upstream thereof, thus breaking the mechanical connection between the shift motor  38  and shift rod  106 . 
   On the other hand, the seventh gear  110   g  located downstream of the sliding gear  110   f  is given a larger facewidth than that of the fifth gear  110   e  and the difference (extra facewidth) extends upward from the level of the top surface of the fifth gear  110   e . The sliding gear  110   f  and seventh gear  110   g  therefore stay meshed after the sliding gear  110   f  is slid upward. So when the boat operator swings the manual lever  120  to the right or left as shown in  FIG. 4 , the rotation is transmitted to the shift rod  106  via the seventh gear  110   g  to the ninth gear  110   i . That is to say, the gear position can be changed by manipulating the manual lever  120  so as to rotate the shift rod  106  manually. 
   The explanation of  FIGS. 5 to 7  will be resumed. The manual lever  120  is provided with a sliding member  124 . The sliding member  124  is given a cylindrical shape and is installed to cover the outer face of the manual lever  120  and be manually slidable in the longitudinal direction by the boat operator. The sliding member  124  is provided with a blocking section  124   a.    
     FIG. 9  is a sectional view similar to  FIG. 5  showing the sliding member  124  after being slid from the location shown in  FIG. 5 .  FIG. 10  is a sectional view taken along line X—X in  FIG. 9  and  FIG. 11  is an enlarged sectional view taken along line XI—XI in  FIG. 9 . 
   As shown in  FIGS. 9 to 11 , when the sliding member  124  is slid downward along the manual lever  120 , the groove  120   c  is blocked by the blocking section  124   a . As a result, the rotary shaft  110   m  is constrained within the groove  120   c , thereby preventing tipping of the manual lever  120  from the upright orientation. 
   When the gear position can be changed normally by the shift motor  38 , the shift rod  106  is protected against manual misoperation by sliding the sliding member  124  downward along the upright manual lever  120  to lock the manual lever  120  in the upright orientation. When the gear position cannot be changed normally by the shift motor  38 , the boat operator unlocks the manual lever  120  by sliding the sliding member  124  upward, swings the manual lever  120  downward by 90 degrees to put it in the horizontal orientation, and then rotates manual lever  120  to the right or left to change the gear position manually. 
   Thus the outboard motor shift device according to this embodiment of the invention is provided in the reduction gear mechanism  110  for transmitting the output of the shift motor  38  to the shift rod  106  at reduced speed and increased torque with a manual operation mechanism that is manually operable for breaking the output transmission train of the reduction gear mechanism  110  and enabling manual rotation of the shift rod  106 . The reliability of the device is therefore enhanced because the gear position can be changed both by the shift motor  38  and manually. In addition, the operation load when the gear position is changed manually is minimized because the output transmission train of the reduction gear mechanism  110  is broken. 
   The manual operation mechanism comprises the sliding gear  110   f  provided in the output transmission train of the reduction gear mechanism  110  so as to be slidable in the facewidth direction and the manual lever  120  that can be manually manipulated to slide and rotate the sliding gear  110   f , and meshing between the sliding gear  110   f  and the fifth gear  110   e  on the upstream side in the output transmission train is disengaged when the sliding gear  110   f  is slid by manual manipulation of the manual lever  120 . The gear position can therefore be changed manually with ease. 
   This embodiment is thus configured to have a device for shifting a gear of an outboard motor ( 10 ) adapted to be mounted on a stern of a boat ( 12 ) among a forward position, a reverse position and a neutral position such that the boat is propelled by a powered propeller ( 32 ) in a direction determined by the gear position, comprising: a clutch ( 102 ) being engageable with a forward gear ( 98 ) or a reverse gear ( 100 ); a shift rod ( 106 ) being rotatable to slide the clutch to engage with the gears; an actuator (electric shift motor  38 ) connected to rotate the shift rod; a speed reduction gear mechanism ( 110 ) transmitting an output of the actuator to the shift rod at a reduced speed; and a manual operation mechanism being manually operable by an operator and breaking output transmission train of the speed reduction gear mechanism such that the shift rod can be manually rotated by the operator. 
   In the device, the manual operation mechanism comprises; a sliding gear ( 110   f ) provided in the output transmission train of the speed reduction gear mechanism to be slidable in a facewidth direction; and a manual lever ( 120 ) being manually manipulatable by the operator to slide and rotate the sliding gear such that the sliding gear is disengaged with a gear ( 110   e ) on an upstream side in the output transmission train. 
   In the device, the sliding gear ( 110   f ) is slidable in the facewidth direction between a first position where it meshes with the gear ( 110   e ) on the upstream side and a gear ( 110   g ) on a downstream side in the output transmission train when not slid by the manual lever and a second position where it only meshes with the gear ( 110   g ) on the downstream side in the output transmission train when slid by the manual lever. 
   The device further includes: a spring ( 112 ) that urges the sliding gear toward the first position. 
   In the device, the manual lever ( 120 ) has a cam member ( 120   d ) that slides the sliding gear when the manual lever is tipped. 
   The device further includes: a member (sliding member  124 ) locking the manual lever not to be manipulated manually. 
   Although in the foregoing description the actuator for rotating the shift rod  106  is explained as being an electric motor (the shift motor  38 ), any of various other types of actuators (such as a hydraulic cylinder) can be used instead. Although in the foregoing description the output transmission mechanism for transmitting the output of the shift motor  38  to the shift rod  106  is explained as being constituted solely of gears, a link mechanism or the like can be used instead. 
   Japanese Patent Application No. 2004-361633 filed on Dec. 14, 2004 is incorporated herein in its entirety. 
   While the invention has thus been shown and described with reference to specific embodiments, it should be noted that the invention is in no way limited to the details of the described arrangements; changes and modifications may be made without departing from the scope of the appended claims.