JP6516922B2 - Balancer device for internal combustion engine - Google Patents

Description

  The present invention relates to a balancer device for an internal combustion engine.

Generally, in an internal combustion engine such as an engine, it is known that vibration is generated by reciprocating motion of a piston. In such internal combustion engines, in order to reduce vibration, those equipped with a balancer device are often used.
As such a balancer device, there is one in which a balancer weight that rotates in a direction opposite to the rotational direction of the crankshaft is disposed coaxially with the crankshaft during operation of the internal combustion engine.
As such conventional techniques, for example, after rotating the crankshaft reversely with the drive gear and the driven gear, power is transmitted to the balancer gear on the crankshaft without changing the rotational direction via the chain drive mechanism. Are disclosed (see, for example, Patent Document 1).
Also, as another technique, for example, there is disclosed one that transmits power to a balancer gear on a crankshaft via an idle gear after the rotation of the crankshaft is reversed between the drive gear and the driven gear (for example, , Patent Document 2).

Japanese Utility Model Publication No. 50-032641 Unexamined-Japanese-Patent No. 2006-214551

However, in the conventional configuration, it is necessary to provide the power transmission mechanism so that the rotation direction of the balancer weight is opposite to the rotation direction of the crankshaft in any of the techniques, so the number of parts increases and the shaft member In addition to the increase in size of the internal combustion engine due to the addition of the above, there is a problem that the freedom of the layout is limited.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and provides a balancer device for an internal combustion engine capable of improving the performance of reducing the vibration of the internal combustion engine while securing the downsizing and the freedom of layout of the internal combustion engine. Intended to be provided.

This specification includes all the contents of Japanese Patent Application No. 2016-071041 filed on March 31, 2016.
In order to achieve the above object, the present invention provides a crankcase (11) having a crank chamber (13c) for accommodating a crankpin (16c) of a crankshaft (16) and a counterweight (16d); And a balancer weight (54) rotating in the direction opposite to the rotating direction of the internal combustion engine, wherein the balancer device is connected to the crankshaft (16) and is the same as the crankshaft (16). A drive gear (39) rotating in a direction, a power transmission mechanism (48) for transmitting rotational power of the drive gear (39), and power from the power transmission mechanism (48) to receive the power from the crankshaft (16) Comprises a driven gear (50, 250) rotating in the reverse direction, and the balancer weight (54) provided on the driven gear (50, 250), the power transmission The structure (48) comprises a carrier member (40) for transmitting power with the start motor (60) of the internal combustion engine via a gear portion (67) provided on the outer periphery, and the carrier member (40) A bevel gear (45) rotatably supported rotatably and engaged with the drive gear (39) and the driven gear (50, 250), and interposed between the carrier member (40) and the drive gear (39) The carrier member (40) or the driven gear (250) has a detected portion (70, 250b) and detects the detected portion (70, 250b) A sensor (71, 81) is provided, and the phase of the carrier member (40) or the driven gear (250) is detected based on the detection by the sensor (71, 81).
According to the present invention, the balancer device of the internal combustion engine includes a power transmission mechanism for transmitting the rotational power of the drive gear to the driven gear by the bevel gear, and the carrier member or driven gear supporting the bevel gear has the detected portion. And a sensor that detects the detected portion, and detects the phase of the carrier member or the driven gear based on the detection by the sensor. As a result, the rotation of the drive gear can be transmitted to the driven gear by the bevel gear rotatably supported by the carrier member, and the balancer weight of the driven gear can be reversely rotated with respect to the crankshaft. Vibration can be reduced. Therefore, the downsizing and the freedom of the layout of the internal combustion engine can be secured. Further, since the phase of the carrier member or the driven gear is detected based on the detection by the sensor for detecting the detected portion of the carrier member or the driven gear, the vibration of the internal combustion engine can be reduced based on the detected phase.
Further, according to the present invention, the carrier member is moved by the starter motor (60) based on the phase of the carrier member (40) or the driven gear (250) detected based on the detection by the sensor (71, 81). (40) or characterized in that the driven gear (250) is rotated to a predetermined phase.
According to the present invention, since the carrier member or the driven gear is rotated to a predetermined phase by the starter motor based on the detection result of the phase by the sensor, even if the phase of the balancer weight is shifted, the starter motor The phase of the balancer weight can be adjusted by rotating the carrier member or the driven gear by this. For this reason, vibration can be effectively reduced.

In the present invention, the start motor (60) is driven such that the detected portion (70) of the carrier member (40) stops at the position of the sensor (71) immediately after the start of the internal combustion engine It is characterized by being.
According to the present invention, the starting motor is driven such that the detected portion of the carrier member stops at the position of the sensor immediately after the start of the internal combustion engine. The phase of the balancer weight can be adjusted with a simple configuration.
In the rotation direction according to the present invention, the start motor (60) engages with the drive gear (39) via the one-way clutch (68) while the internal combustion engine is stopped. Is characterized in that the carrier member (40) is driven to rotate in the opposite direction, and the carrier member (40) is rotated to the predetermined phase.
According to the present invention, the start motor is driven so that the carrier member rotates in the opposite direction to the rotational direction in which the carrier member meshes with the drive gear via the one-way clutch while the internal combustion engine is stopped. It is rotated to a predetermined phase. Thus, even when the internal combustion engine is stopped, the carrier member can be rotated by rotating the one-way clutch in the reverse direction, and the phase of the balancer weight can be adjusted.

Furthermore, the present invention is characterized in that the rotational speed of the driven gear (50, 250) is the same as the rotational speed of the crankshaft (16).
According to the present invention, since the rotational speed of the driven gear is the same as the rotational speed of the crankshaft, a balancer weight can be provided on the driven gear to reduce the vibration of the crankshaft.
Furthermore, the present invention is characterized in that a reduction gear (65) is provided between the output gear (62) of the starting motor (60) and the gear portion (67) of the carrier member (40).
According to the present invention, since the reduction gear is provided between the output gear of the start motor and the gear portion of the carrier member, the torque of the start motor is amplified by the reduction gear and transmitted to the carrier member to carry out internal combustion via the carrier member. The engine can be started. Further, when the rotation is transmitted from the carrier member to the start motor via the reduction gear, the torque transmitted from the carrier member to the start motor can be reduced because it functions as a speed increasing gear. For this reason, when the starter motor is stopped, the carrier member can be fixed by the rotational resistance of the starter motor, and the driven gear can be reversely rotated by the bevel gear supported by the carrier member.

Further, the carrier member (40) has a window (43) penetrating both side surfaces, and the bevel gear (45) is disposed with its teeth facing the window (43). It is characterized by
According to the present invention, since the bevel gear is disposed with its teeth facing the window of the carrier member, the drive gear and the driven gear can be engaged via the bevel gear passing through the window. .
The drive gear (39) is characterized in that it is formed on the side of a flywheel (33) connected to the crankshaft (16).
According to the present invention, since the drive gear is formed on the side surface of the flywheel connected to the crankshaft, the number of parts can be reduced and downsizing can be achieved.
Furthermore, according to the present invention, the carrier member (40) has a cylindrical portion (41) that accommodates the crank shaft (16) inside in the radial direction, and the carrier member (40) does not A driven gear (50, 250) is disposed, and a circlip (52) is provided at an end of the cylindrical portion (41).
According to the present invention, the driven gear is disposed radially outside the cylindrical portion of the carrier member, and the circlip is provided at the end of the cylindrical portion. Thus, the driven gear disposed on the radially outer side of the cylindrical portion of the carrier member can be fixed by the circlip, and the carrier member and the driven gear can be configured as one assembly. For this reason, miniaturization and improvement of the assemblability can be achieved.

In the balancer device for an internal combustion engine according to the present invention, downsizing of the internal combustion engine and freedom of layout can be ensured, and vibration can be effectively reduced by adjusting the phase of the balancer weight.
Further, the phase of the balancer weight can be adjusted with a simple configuration based on the detected portion immediately after the start of the internal combustion engine.
Further, even while the internal combustion engine is stopped, the carrier member can be rotated by rotating the one-way clutch in the reverse direction, and the phase of the balancer weight can be adjusted.
Furthermore, a balancer weight can be provided on a driven gear that rotates at the same speed as the rotational speed of the crankshaft to reduce vibration.
In addition, since the reduction gear is provided, the internal combustion engine can be easily started by the start motor. In addition, the carrier member can be fixed by the rotational resistance of the starter motor.
Further, the drive gear and the driven gear can be meshed with a simple structure via a bevel gear passing through the window portion of the carrier member.
In addition, the number of parts can be reduced, and the balancer apparatus can be miniaturized.
Furthermore, the carrier member and the driven gear can be configured as one assembly by the circlip, and the assemblability is good.

FIG. 1 is a schematic cross-sectional view of an internal combustion engine to which a balancer device according to a first embodiment of the present invention is applied. FIG. 2 is a side view of the carrier member seen from the drive gear side. FIG. 3 is a cross-sectional view showing the state of the power transmission mechanism etc. at the start of the engine. FIG. 4 is a cross-sectional view showing the state of the power transmission mechanism and the like during operation of the engine. FIG. 5 is a diagram showing the balance state of the primary vibration of the engine. FIG. 6 is a flowchart of weight phase adjustment processing. FIG. 7 is a schematic cross-sectional view of an internal combustion engine to which a balancer device according to a second embodiment of the present invention is applied.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 is a schematic cross-sectional view of an internal combustion engine to which a balancer device according to a first embodiment of the present invention is applied.
As shown in FIG. 1, the engine 10 which is an internal combustion engine in the present embodiment is a single-cylinder four-stroke air-cooled engine. The engine 10 is started by a start motor 60. The engine 10 is mounted on, for example, a saddle-ride type vehicle such as a motorcycle.

The engine 10 includes a crankcase 11 and a cylinder portion 12 (FIG. 2) extending upward from the upper surface of the crankcase 11.
The crankcase 11 includes a crankcase main body 13 accommodating the crank shaft 16 therein, and a crankcase cover 14 attached to a side surface of the crankcase main body 13.
The crankcase main body 13 includes a first crankcase 13a and a second crankcase 13b which are divided in the axial direction of the crankshaft 16 (the left and right direction of the vehicle), and is formed in a left and right divided structure.

A crank chamber 13 c is formed inside the crankcase body 13.
The crankcase main body 13 includes a pair of left and right bearings 15, 15 supported by the one side crankcase 13a and the other side crankcase 13b. The crankshaft 16 is supported by bearings 15 and 15 and is disposed laterally with its axis perpendicular to the traveling direction of the vehicle.
The crankshaft 16 is supported by bearings 15 and 15 and is provided with a crank journal 16a as a rotation center, a crank web 16b formed to have a diameter larger than the crank journal 16a, and a crankpin 16c supported via the crank web 16b. And The crank web 16b is provided with a counterweight 16d for rotating balance at a position opposite to the crank pin 16c across the crank journal 16a.
The crank pin 16c, the crank web 16b and the counterweight 16d are accommodated in the crank chamber 13c and disposed between the left and right bearings 15, 15. The crank journal 16a extends outside the crank chamber 13c.

The cylinder unit 12 includes a cylinder block 20 (FIG. 2), a cylinder head (not shown), and a cylinder head cover (not shown) in this order from the crankcase 11 side. A combustion chamber (not shown) is formed inside the cylinder head.
In the cylinder block 20, a piston 21 (FIG. 5) is slidably accommodated. The piston 21 is connected to a crank pin 16c of the crankshaft 16 by a connecting rod 22 (FIG. 5). The crankshaft 16 is rotationally driven by transmitting the reciprocation of the piston 21 by combustion in the combustion chamber through the connecting rod 22.

  Further, a sprocket 23 is attached to the crankshaft 16, and a cam chain 24 is hooked between the sprocket 23 and a camshaft sprocket (not shown) provided on a camshaft inside the head cover. It has been passed. The cam shaft is driven by the crank shaft 16 through the cam chain 24. As a result, a valve mechanism that operates an intake and exhaust valve (not shown) provided in the cylinder head is driven.

By attaching the crankcase cover 14 to the side surface of the one-side crankcase 13a, a generator chamber 26 is formed between the crankcase cover 14 and the crankcase main body 13.
The generator chamber 26 accommodates a generator 30 that generates electric power by rotation of the crankshaft 16 and a flywheel 33 of the crankshaft 16.
The flywheel 33 is fixed to an end of the crankshaft 16 via a key 32. The flywheel 33 includes a flange portion 37 fixedly fitted to the crank shaft 16 and a disk-shaped rotating portion 38 extending radially outward from the flange portion 37. The flywheel 33 rotates integrally with the crankshaft 16.

A drive gear 39 formed annularly is provided integrally with the flywheel 33 on the inner side surface of the rotating portion 38 of the flywheel 33, that is, the surface on the crank chamber 13c side. The drive gear 39 includes drive-side teeth 39 a annularly arranged to go around the crankshaft 16. The drive side teeth 39a project toward the crankcase main body 13 side.
The generator 30 includes a cylindrical rotor 34 fixed to the outer surface of the rotating portion 38 of the flywheel 33 and a stator 36 disposed inside the rotor 34 and fixed to the crankcase cover 14.

Between the flywheel 33 and the crankcase main body 13 on the crankshaft 16, the rotational power of the driven gear 50 rotatable relative to the crankshaft 16 and the drive gear 39 of the flywheel 33 is transmitted to the driven gear 50. Power transmission mechanism 48 is disposed.
The power transmission mechanism 48 includes a disk-shaped carrier member 40 provided rotatably relative to the crankshaft 16, a plurality of bevel gears 45, 45 supported by the carrier member 40, the carrier member 40, and a drive gear. And a one-way clutch 68 interposed therebetween.

FIG. 2 is a side view of the carrier member 40 viewed from the drive gear 39 side. In FIG. 2, the drive gear 39, the flywheel 33 and the crankcase cover 14 are not shown.
Referring to FIGS. 1 and 2, the carrier member 40 integrally includes a cylindrical portion 41 fitted to the outer peripheral portion of the crankshaft 16 and a disc portion 42 extending outward in the radial direction from the cylindrical portion 41. Prepare.
The cylindrical portion 41 of the carrier member 40 includes a clutch connection portion 41 a connected to the drive gear 39 via the one-way clutch 68 and a driven gear support portion 41 b for supporting the driven gear 50. In the axial direction, the clutch connection portion 41a is provided on the flywheel 33 side across the disc portion 42, and the driven gear support portion 41b is provided on the crankcase main body 13 side across the disc portion 42.
The cylindrical portion 41 is supported by the outer peripheral portion of the crankshaft 16 via a bearing 66 provided on the inner peripheral portion. For this reason, the carrier member 40 is rotatable relative to the crankshaft 16.
That is, the carrier member 40 accommodates the crankshaft 16 inside the radial direction of the cylindrical portion 41, and supports the driven gear 50 outside the radial direction of the cylindrical portion 41.

In the disc portion 42 of the carrier member 40, a plurality of window portions 43, 43... Penetrating through both side surfaces of the disc portion 42 are formed. The windows 43, 43,... Are formed closer to the outer periphery of the disk portion 42, and are formed in plural (four in the present embodiment) at predetermined intervals in the circumferential direction.
Further, support portions 44, 44,... Extending toward the drive gear 39 are formed at positions of the disk portion 42 on the radially outer side of the window portions 43, 43,. At the tip of each support portion 44, a shaft support member 44a extending toward the crankshaft 16 in a posture orthogonal to the crankshaft 16 is provided.
Each bevel gear 45 is pivotally supported at its central portion by the pivoting member 44a, and rotates around the pivoting member 44a.
On the outer peripheral surface of the disc portion 42 of the carrier member 40, a gear portion 67 to which power on the starting motor 60 side is input is formed over the entire periphery.

  The carrier member 40 includes one columnar protrusion 70 (detected portion) protruding from the side surface of the disk portion 42 to the flywheel 33 side. The protrusion 70 extends in parallel with the crankshaft 16. The projecting portion 70 is provided in the vicinity of the outer peripheral surface of the disk portion 42, and is provided at a position substantially overlapping the gear portion 67 in the radial direction when the crankshaft 16 is viewed in the axial direction. The protrusion 70 rotates integrally with the carrier member 40.

The engine 10 is provided with a sensor 71 that detects the protrusion 70. The sensor 71 is fixed to the crankcase cover 14 radially outside the outer peripheral surface of the carrier member 40. The sensor 71 is a contact-type sensor, and includes a cylindrical main body 71a inserted into the crankcase cover 14, a detector 71b provided at the tip of the main body 71a and contacting the projection 70, and the sensor 71 as an engine And a wiring unit 71 c connected to the control unit 75 of FIG.
The sensor 71 is disposed such that the detection unit 71 b is located on the rotation trajectory of the protrusion 70.
In FIG. 2, the upper direction of the drawing is the upper direction of the engine 10, and the sensor 71 is disposed below the axis 16 e of the crankshaft 16 and inserted into the lower surface portion 14 a of the crankcase cover 14 from below. As a result, the upper portion of the crankcase cover 14 can block rain, and since rainwater hardly accumulates on the lower surface of the crankcase cover 14, rainwater can be prevented from entering the mounting portion of the sensor 71.
The control unit 75 detects the phase of rotation of the carrier member 40 based on the detection result of the sensor 71.

The driven gear 50 is formed in a disk shape, and is supported by the outer peripheral portion of the driven gear support portion 41 b of the carrier member 40 via a bearing 51 provided at the center portion. The driven gear 50 is rotatable relative to the carrier member 40.
The driven gear 50 is provided with a driven side tooth portion 50 a annularly arranged on the side surface on the carrier member 40 side. The driven side tooth portion 50 a is provided to face the drive side tooth portion 39 a of the drive gear 39. Further, the number of teeth of the driven side tooth portion 50a and the number of teeth of the driving side tooth portion 39a are the same.
A balancer weight 54 is integrally provided on part of the surface of the driven gear 50 on the crankcase main body 13 side.

The driven gear 50 is axially positioned by a circlip 52 engaged with the shaft end of the driven gear support portion 41 b on the side of the crankcase main body 13, and is integrally assembled to the carrier member 40. As described above, since the driven gear 50 is fitted to the carrier member 40 and the driven gear 50 is fixed by the circlip 52, the carrier member 40 and the driven gear 50 can be assembled as one unit. For this reason, compactness and improvement of the assemblability can be achieved.
The driven gear 50 is arranged at a position closest to the crankcase main body 13 among the drive gear 39, the carrier member 40 and the driven gear 50 arranged in the axial direction of the crankshaft 16.

The bevel gears 45 are disposed to face the windows 43, and the drive-side teeth 39a of the drive gear 39 mesh with the bevel gears 45 from the flywheel 33 side. Each bevel gear 45 is exposed to the side of the crankcase main body 13 through each window 43 and meshes with the driven side teeth 50 a of the driven gear 50.
When the drive gear 39 rotates with the rotation of the crankshaft 16, the rotation of the drive gear 39 is transmitted to the driven gear 50 via the bevel gears 45, and the driven gear 50 is reverse to the rotation direction of the drive gear 39. To rotate. Here, since the number of teeth of the driven side tooth portion 50 a and the number of teeth of the driving side tooth portion 39 a are the same, the driven gear 50 has the rotational speed of the crankshaft 16 in the opposite direction to the rotation of the crankshaft 16. Rotate at the same speed. That is, the rotation speed of the crankshaft 16 and the rotation speed of the driven gear 50 are the same.

As shown in FIG. 1, the engine 10 includes a starter motor 60 disposed in the vicinity of the crankcase 11 and a speed reducing member 63 for decelerating the rotation of the starter motor 60 and transmitting it to the carrier member 40.
The output shaft 61 of the starting motor 60 extends in parallel with the crankshaft 16, and the output shaft 61 is provided with an output gear portion 62 (output gear portion) meshing with the speed reducing member 63.
The reduction member 63 integrally includes an input gear portion 64 meshing with the output gear portion 62 and a reduction gear portion 65 (reduction gear) meshing with the gear portion 67 on the outer periphery of the carrier member 40. Since the rotation of the starter motor 60 is decelerated and transmitted to the carrier member 40 via the reduction member 63, the torque transmitted to the crankshaft 16 can be increased, and the engine 10 can be easily started.

The one-way clutch 68 is formed in a ring shape interposed between the clutch connecting portion 41 a of the cylindrical portion 41 of the carrier member 40 and the gear side clutch connecting portion 39 b of the inner peripheral portion of the drive gear 39.
The one-way clutch 68 is a clutch mechanism that limits the transmission direction of rotation (torque) between the carrier member 40 and the drive gear 39 (flywheel 33) in one direction.
Specifically, when the one-way clutch 68 starts the engine 10 by rotating the crankshaft 16 by the starting motor 60, the one-way clutch 68 transmits the power of the starting motor 60 from the carrier member 40 to the driving gear 39. Interlock to enable transmission of rotation (torque).

In addition, when the rotational speed of the crankshaft 16 becomes faster than the rotational speed of the carrier member 40 for the reason that the start motor 60 is stopped after the engine 10 is started, the one-way clutch 68 When it is opposite to the start of the clutch, the clutch slips and cuts off the transmission of rotation (torque). For this reason, the start motor 60 is prevented from being rotated by the operation of the engine 10.
When the starter motor 60 is stopped during operation of the engine 10, the carrier member 40 is fixed by the resistance of the starter motor 60 transmitted to the carrier member 40 via the reduction member 63 and does not rotate. That is, in a state where the start motor 60 is stopped while the engine 10 is in operation, the carrier member 40 is fixed and does not rotate, and the drive gear 39 idles relative to the carrier member 40.
In the present embodiment, when the rotation is transmitted from the carrier member 40 to the starting motor 60 via the reduction member 63, the acceleration direction is obtained, and the torque of the carrier member 40 is reduced by the reduction member 63. It is transmitted to. Therefore, the carrier member 40 can be fixed by the stopped starting motor 60.

Next, operations of the power transmission mechanism 48 and the like at the time of start-up and operation of the engine 10 will be described.
FIG. 3 is a cross-sectional view showing the state of the power transmission mechanism 48 and the like when the engine 10 is started. In FIG. 3, the transmission direction of the torque due to the rotation of the starter motor 60 is illustrated by an arrow.
Referring to FIG. 3, when the engine 10 is started, the control unit 75 controls the injection amount of fuel and the ignition timing, and the start motor 60 is driven. The rotation of the starter motor 60 is transmitted to the carrier member 40 via the speed reduction member 63, transmitted from the carrier member 40 to the drive gear 39 (flywheel 33) via the one-way clutch 68, and the crankshaft 16 is rotated. . In this state, since the one-way clutch 68 engages and the carrier member 40 and the flywheel 33 rotate integrally, the bevel gear 45 does not rotate. For this reason, when starting the engine 10, the carrier member 40, the flywheel 33, and the driven gear 50 normally rotate integrally.

FIG. 4 is a cross-sectional view showing the state of the power transmission mechanism 48 and the like while the engine 10 is in operation. In FIG. 4, the transmission direction of the torque from the crankshaft 16 to the driven gear 50 is illustrated by an arrow.
Referring to FIG. 4, in a state where the engine 10 is operating and the driving of the starting motor 60 is stopped, the carrier member 40 is restricted in rotation by the rotational resistance of the starting motor 60 and does not rotate. Further, since the one-way clutch 68 is disconnected, the rotation is not transmitted from the drive gear 39 to the carrier member 40, and the drive gear 39 only rotates relative to the fixed carrier member 40.
In this state, the rotation of the crankshaft 16 is transmitted to the driven gear 50 via the drive gear 39 and the bevel gears 45, and the driven gear 50 rotates in the reverse direction with respect to the drive gear 39 and the crankshaft 16. That is, while the engine 10 is in operation, the driven gear 50 continues to rotate in the opposite direction to the crankshaft 16 and at the same speed (the same rotational speed) as the rotational speed of the crankshaft 16.

In the present embodiment, the driven gear 50 having the balancer weight 54 is provided on the crankshaft 16 coaxially with the crankshaft 16, and the rotation of the drive gear 39 of the flywheel 33 is provided on the crankshaft 16. , And is transmitted to the driven gear 50 via the bevel gears 45 supported by the As a result, since a dedicated shaft member for supporting the driven gear 50 is not required, the engine 10 capable of reducing the vibration can be configured compactly by the balancer weight 54.
The driven gear 50 is disposed at a position closest to the crankcase main body 13 among the drive gear 39, the carrier member 40 and the driven gear 50 arranged in the axial direction of the crankshaft 16. Therefore, the distance between the balancer weight 54 and the counter weight 16 d in the axial direction of the crankshaft 16 can be reduced, and the coupling vibration can be reduced.
Further, since the rotation of the drive gear 39 is transmitted to the driven gear 50 by the bevel gears 45, the driven gear 50 can be rotated in the reverse direction with respect to the crankshaft 16 with a simple structure. Therefore, the balancer weight 54 can be provided on the driven gear 50 to effectively function as a balancer.

FIG. 5 is a diagram showing the balance state of the primary vibration of the engine 10. As shown in FIG.
In FIG. 5, corresponding to each phase of the crankshaft 16 including the counterweight 16d, a piston side synthetic inertia force F1 in which the phase of the balancer weight 54 and the inertia force of the piston 21 and the connecting rod 22 are synthesized sequentially from the top of the page. An inertial force F2 of the balancer weight 54 and a synthetic inertial force F3 obtained by combining the piston-side synthetic inertial force F1 and the inertial force F2 of the balancer weight 54 are illustrated. Further, in FIG. 5, cycles (corresponding to one rotation of the crankshaft 16) from the top dead center to the bottom dead center to return to the top dead center are shown in order from the left side of the drawing at every 45 °. There is.

In the engine 10, assuming that the virtual mass 55 of the reciprocating unit constituted by the piston 21 and the connecting rod 22 is 100%, the mass of the counter weight 16d is set to 50%, and the mass of the balancer weight 54 is set to 50%. It is done.
When the piston 21 is at the top dead center, the counterweight 16d is rotated 180 ° on the opposite side of the crankpin 16c on the crank web 16b with respect to the rotation center of the crankshaft 16, ie, the crankpin 16c. Are located at different positions.
When the piston 21 is at the top dead center, the virtual mass 55 that generates vibration due to the rotation of the crankshaft 16 is positioned at a position 180 ° out of phase with the counter weight 16 d.
When the piston 21 is at the top dead center, the phase of the balancer weight 54 is the same as the phase of the counter weight 16 d and is 180 ° out of phase with the crank pin 16 c.

The crankshaft 16 rotates in a rotational direction A indicated by the arrow. The virtual mass 55 rotates in the opposite direction to the crankshaft 16. That is, the virtual mass 55 rotates at the same speed as the crankshaft 16 in the reverse rotational direction B opposite to the rotational direction A.
The counterweight 16 d that rotates integrally with the crankshaft 16 rotates at the same speed as the crankshaft 16 in the rotational direction A.
The balancer weight 54 is provided on the driven gear 50 that rotates in the reverse direction to the crankshaft 16, and thus rotates at the same speed as the crankshaft 16 in the reverse rotation direction B.
The balancer weight 54 and the virtual mass 55 rotate at the same speed in the reverse rotation direction B with phases different from each other by 180 °.

Since the mass of the counterweight 16d is 50% of the virtual mass 55, the inertial force of the virtual mass 55 is not completely canceled by the counterweight 16d and 50% remains. Therefore, the piston side synthetic inertial force F1 is directed from the rotation center of the crankshaft 16 in the direction in which the virtual mass 55 is located. For example, in the state of top dead center, the piston side synthetic inertia force F1 is directed to the upper side where the piston 21 is located. The piston-side synthetic inertia force F1 rotates at the same speed as the crankshaft 16 in the reverse rotation direction B as the virtual mass 55 does.
The inertia force F2 of the balancer weight 54 is directed from the rotation center of the crankshaft 16 in the direction in which the balancer weight 54 is located. For example, in the state of top dead center, the piston side synthetic inertia force F1 is directed to the lower side opposite to the side where the piston 21 is located. The inertia force F2 of the balancer weight 54 rotates at the same speed as the crankshaft 16 in the reverse rotation direction B as the balancer weight 54 does.

In the state of FIG. 5, the piston-side synthetic inertial force F1 and the inertial force F2 of the balancer weight 54 rotate at the same speed in the reverse rotation direction B with a phase different from each other by 180 °, and the magnitude of the piston-side synthetic inertial force F1 and the balancer The magnitude of the inertial force F2 of the weight 54 is equal. As a result, the combined inertia force F1 and the inertia force F2 of the balancer weight 54 cancel each other over all phases, so that the combined inertia force F3 becomes zero in all phases. For this reason, the primary vibration of the engine 10 can be effectively reduced. For example, in the bottom dead center state where the crankshaft 16 has rotated 180 ° in the rotational direction A from the top dead center state, the piston side synthetic inertial force F1 is directed downward as opposed to the piston 21 side. The inertia force F2 of 54 points in the opposite direction to the piston side synthetic inertia force F1. Thereby, it is possible to cancel the vibration in the direction in which the piston 21 reciprocates.
When the crankshaft 16 is rotated by 90 ° in the rotational direction A from the top dead center state, the piston side synthetic inertial force F1 is directed in the direction orthogonal to the direction in which the piston 21 reciprocates, but the balancer weight 54 The inertial force F2 of the motor 1 is directed in the opposite direction to the piston side synthetic inertial force F1. Thereby, the vibration in the direction orthogonal to the direction in which the piston 21 reciprocates can be canceled.

  In the present embodiment, a position state in which the balancer weight 54 is in a phase different by 180 ° from the virtual mass 55 is referred to as the “initial position” of the balancer weight 54. When the piston 21 is at the top dead center with the balancer weight 54 in the “initial position”, the phase of the balancer weight 54 is the same as the phase of the counter weight 16 d. By positioning the balancer weight 54 in the “initial position”, the synthetic inertial force F3 can be made zero at all phases of the 360 ° rotation of the crankshaft 16, and the vibration of the engine 10 can be reduced.

  In the present embodiment, since the carrier member 40 supporting the bevel gear 45 is rotatable, when the phase of rotation of the carrier member 40 changes, the driven gear 50 is rotated via the bevel gear 45, and the drive gear 39 (see FIG. The phase of the driven gear 50 with respect to the side of the crankshaft 16 changes. As the phase of the driven gear 50 changes, the phase of the balancer weight 54 with respect to the crankshaft 16 changes. That is, the phase of the carrier member 40 directly corresponds to the phase of the balancer weight 54, and the phase of the balancer weight 54 can be adjusted by adjusting the phase of the carrier member 40.

Thus, since the carrier member 40 is rotatable, when the phase of the carrier member 40 deviates from the predetermined phase, the phase of the balancer weight 54 with respect to the crankshaft 16 changes, and the performance of reducing the vibration by the balancer device changes. Resulting in.
In the present embodiment, the carrier member 40 is set to a predetermined phase, that is, a phase at which the balancer weight 54 is positioned at the “initial position”.

The controller 75 detects the phase of the carrier member 40 based on the detection of the sensor 71, rotates the carrier member 40 to a predetermined phase by the starter motor 60, and returns the balancer weight 54 to the "initial position". I do. Here, the carrier member 40 can change the phase of rotation by being driven by the starting motor 60 regardless of whether the engine 10 is operating or stopping.
The protrusion 70 and the sensor 71 of the carrier member 40 are arranged such that the balancer weight 54 is positioned at the “initial position” when the carrier member 40 is positioned at a phase at which the protrusion 70 is detected by the sensor 71. That is, when the phase at which the protrusion 70 is detected by the sensor 71 is the predetermined phase of the carrier member 40 and the carrier member 40 is positioned at the predetermined phase, the balancer weight 54 is positioned at the “initial position”.

FIG. 6 is a flowchart of weight phase adjustment processing.
First, the control unit 75 detects that the main power of the saddle-ride type vehicle on which the engine 10 is mounted is turned on (step S1), for example, a starting motor based on a starting command by operation of an engine start button The motor 60 is driven to start the engine 10, and immediately after the engine 10 is started, it is determined whether or not the protrusion 70 of the carrier member 40 is detected by the sensor 71 (step S2). The start of the engine 10 is detected based on, for example, a detection value of a crank angle sensor that detects the rotation of the crankshaft 16.
In step S2, the control unit 75 detects the phase of the carrier member 40. That is, if the protrusion 70 of the carrier member 40 is detected by the sensor 71, the carrier member 40 is positioned at a predetermined phase, and in this state, the balancer weight 54 is at the “initial position”. Also, if the protrusion 70 of the carrier member 40 is not detected by the sensor 71, the carrier member 40 is at a phase other than the predetermined phase, and in this state, the balancer weight 54 is not at the “initial position”. .

When the protrusion 70 of the carrier member 40 is detected by the sensor 71 (step S2: YES), the control unit 75 ends the process. In this case, since the balancer weight 54 is in the “initial position” and in the proper position, there is no need to adjust the phase of the balancer weight 54.
When the protrusion 70 of the carrier member 40 is not detected by the sensor 71 (step S2: NO), the control unit 75 reverses the direction in which the starter motor 60 starts the engine 10 immediately after the engine 10 starts. That is, the one-way clutch 68 is driven in the direction to be disconnected (step S3).

Subsequently, the control unit 75 returns to step S2, and determines whether the protrusion 70 of the carrier member 40 is detected by the sensor 71. That is, the control unit 75 continues the driving of the starting motor 60 until the sensor 70 detects the projection 70 of the carrier member 40. That is, the starter motor 60 is driven so that the protrusion 70 of the carrier member 40 stops at the position of the sensor 71. Then, when the protrusion 70 is detected by the sensor 71, the control unit 75 stops the start motor 60, and ends the process.
Thus, the balancer weight 54 can be adjusted to be in the “initial position” immediately after the engine 10 is started. Therefore, the vibration of the engine 10 can be reduced.

As described above, according to the first embodiment to which the present invention is applied, the balancer device of the engine 10 includes the crankcase 11 having the crank chamber 13c for accommodating the crankpin 16c of the crankshaft 16 and the counterweight 16d. And a balancer weight 54 that rotates in the direction opposite to the rotational direction of the crankshaft 16, and is connected to the crankshaft 16 and rotates in the same direction as the crankshaft 16; The power transmission mechanism 48 includes a power transmission mechanism 48 for transmitting, a driven gear 50 that receives power from the power transmission mechanism 48 and rotates in the opposite direction to the crankshaft 16, and a balancer weight 54 provided on the driven gear 50. A carrier member 40 for transmitting power between the engine 10 and the starter motor 60 via a gear portion 67 provided on the outer periphery, .., And a one-way clutch 68 interposed between the carrier member 40 and the drive gear 39. The bevel gear 45 is rotatably supported by the carrier member 40 and engaged with the drive gear 39 and the driven gear 50. The carrier member 40 has a protrusion 70 and is provided with a sensor 71 provided on the crankcase 11 for detecting the protrusion 70, and detects the phase of the carrier member 40 based on the detection by the sensor 71. Thereby, the rotation of the drive gear 39 is transmitted to the driven gear 50 by the bevel gears 45, 45... Rotatably supported by the carrier member 40, and the balancer weight 54 of the driven gear 50 is reversely rotated with respect to the crankshaft 16. Because of this, it is possible to reduce vibration with a compact structure. For this reason, downsizing of the engine 10 and freedom of layout can be secured. In addition, since the phase of the carrier member 40 is detected based on the detection by the sensor 71 that detects the protrusion 70 of the carrier member 40, the result of this detection can be used to reduce the vibration of the engine 10.
Further, the balancer device of the engine 10 causes the start motor 60 to rotate the carrier member 40 to a predetermined phase based on the phase of the carrier member 40 detected based on the detection by the sensor 71, so the phase of the balancer weight 54 is shifted. Even in the case where the carrier weight 40 is reduced, the phase of the balancer weight 54 can be adjusted by rotating the carrier member 40 by the starter motor 60. For this reason, the vibration of the engine 10 can be effectively reduced.

In addition, since the start motor 60 is driven so that the protrusion 70 of the carrier member 40 stops at the position of the sensor 71 immediately after the start of the engine 10, the protrusion 70 of the carrier member is referred to immediately after the start of the engine 10. The phase of the balancer weight 54 can be adjusted with a simple configuration.
In addition, the start motor 60 is driven so that the carrier member 40 rotates in the opposite direction to the rotational direction in which the carrier member 40 meshes with the drive gear 39 via the one-way clutch 68 while the engine 10 is stopped. 40 is rotated to a predetermined phase. Thus, even when the engine 10 is stopped, the carrier member 40 can be rotated by rotating the one-way clutch 68 in the reverse direction, and the phase of the balancer weight 54 can be adjusted.

Furthermore, since the rotational speed of the driven gear 50 is the same as the rotational speed of the crankshaft 16, the balancer weight 54 can be provided on the driven gear 50 to reduce the vibration of the crankshaft 16.
Further, since the reduction gear portion 65 is provided between the output gear portion 62 of the start motor 60 and the gear portion 67 of the carrier member 40, the torque of the start motor 60 is amplified by the reduction gear portion 65 and transmitted to the carrier member 40. The engine 10 can be started via the carrier member 40. Further, when the rotation is transmitted from the carrier member 40 to the starting motor 60 via the reduction gear portion 65, the torque transmitted from the carrier member 40 to the starting motor 60 since the reduction gear portion 65 functions as a speed increasing gear. Can be made smaller. For this reason, in a state where the starting motor 60 is stopped, the carrier member 40 can be fixed by the rotational resistance of the starting motor 60, and the driven gear 50 is supported by the bevel gears 45, 45 ... supported by the carrier member 40. Can be reversed.

Further, the carrier member 40 is provided with windows 43, 43,... Penetrating through both side surfaces, and the bevel gears 45, 45,... Are arranged with their teeth facing the windows 43, 43,. The drive gear 39 and the driven gear 50 can be meshed with each other via bevel gears 45, 45... Passing through the portions 43, 43.
Further, since the drive gear 39 is formed on the side surface of the flywheel 33 connected to the crankshaft 16, the number of parts can be reduced, and the size can be reduced.
Furthermore, the carrier member 40 has a cylindrical portion 41 that accommodates the crankshaft 16 radially inside, the driven gear 50 is disposed radially outside the cylindrical portion 41, and the end portion of the cylindrical portion 41 A clip 52 is provided. Thus, the driven gear 50 disposed on the radially outer side of the cylindrical portion 41 of the carrier member 40 can be fixed by the circlip 52, and the carrier member 40 and the driven gear 50 can be configured as one assembly. For this reason, miniaturization and improvement of the assemblability can be achieved.

Second Embodiment
Hereinafter, a second embodiment to which the present invention is applied will be described with reference to FIG. In the second embodiment, parts that are the same as in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.
In the first embodiment, the configuration for detecting the phase of the carrier member 40 based on the detection by the sensor 71 has been described, but in the second embodiment, the phase of the driven gear 250 is detected by the sensor 81. The configuration will be described.

FIG. 7 is a schematic cross-sectional view of an internal combustion engine to which a balancer device according to a second embodiment of the present invention is applied.
In the second embodiment, a sensor 81 is provided instead of the sensor 71 that detects the protrusion 70 of the carrier member 40, and a driven gear 250 is provided instead of the driven gear 50.
The driven gear 250 includes a driven side tooth portion 50a, a balancer weight 54, and a detected portion 250b protruding radially outward from the outer peripheral portion. The driven gear 250 is configured in the same manner as the driven gear 50 of the first embodiment except that the driven gear 250 includes the detected portion 250b.

The sensor 81 detects the detected portion 250 b of the driven gear 250. The sensor 81 is disposed on the inner side of the one-side crankcase 13 a, and approaches the detected portion 250 b from the radially outer side of the driven gear 250. The sensor 81 is fixed to the one side crankcase 13a by, for example, a bolt.
The sensor 81 detects the phase of the balancer weight 54 of the driven gear 250 by detecting the detected portion 250 b.
The sensor 81 is a noncontact sensor using, for example, a magnetic force. The sensor 81 is connected to the control unit 75 via the wiring unit 271 c. The sensor 81 outputs a change in magnetic flux generated when the detected portion 250 b passes near the sensor 81 as the driven gear 250 rotates, to the control unit 75 as a pulse wave corresponding to the rotation of the driven gear 250.

The crankcase cover 14 in the generator chamber 26 is provided with a crank angle sensor 90 for detecting the rotation of the crankshaft 16.
On the outer peripheral surface of a cylindrical rotor 34 fixed to a flywheel 33 that rotates integrally with the crankshaft 16, a crank angle detection portion 34a that protrudes radially outward is provided.
The crank angle sensor 90 detects the crank angle detection portion 34 a of the rotor 34 to detect the phase of rotation of the crankshaft 16. The crank angle sensor 90 is fixed to the crankcase cover 14 by, for example, a bolt.
The crank angle sensor 90 is, for example, a non-contact sensor using a magnetic force. The crank angle sensor 90 is connected to the control unit 75 via the wiring unit 271 d. The crank angle sensor 90 changes the magnetic flux generated when the crank angle detected portion 34 a passes near the crank angle sensor 90 with the rotation of the crankshaft 16 as a pulse wave according to the rotation of the crankshaft 16. It is output to the control unit 75.

The control unit 75 compares the phase of the balancer weight 54 detected by the sensor 81 with the phase of the crankshaft 16 detected by the crank angle sensor 90. Then, the control unit 75 drives the starter motor 60 based on the result of the comparison to rotate the carrier member 40 to bring the balancer weight 54 into the phase of the “initial position”. Thereby, the vibration of the engine 10 can be effectively reduced.
That is, in the first embodiment, the phase of the balancer weight 54 is indirectly detected by detecting the phase of the carrier member 40. However, in the second embodiment, the phase of the balancer weight 54 is detected by the sensor 81. To detect directly.
Further, the control unit 75 may drive the starter motor 60 based on the result of the comparison to rotate the carrier member 40 and change the balancer weight 54 to an arbitrary phase. Thereby, the performance of vibration reduction by the balancer device can be changed, and the magnitude of the vibration generated in the engine 10 can be arbitrarily adjusted.

The above embodiment shows one aspect to which the present invention is applied, and the present invention is not limited to the above embodiment.
In the above embodiment, the start motor 60 is described as being driven so that the protrusion 70 of the carrier member 40 stops at the position of the sensor 71 immediately after the start of the engine 10, but the present invention is limited thereto It is not something to be done. The start motor 60 can be driven even when the engine 10 is stopped, and the protrusion 70 of the carrier member 40 may be stopped at the position of the sensor 71 by this drive. In this case, for example, after the engine 10 is stopped, the control unit 75 detects the protrusion 70 of the carrier member 40 by the sensor 71, and drives the start motor 60 when the protrusion 70 is not detected. The carrier member 40 is rotated to a predetermined phase, and then the main power source of the saddle-ride type vehicle is turned off.

10 Engine (internal combustion engine)
11 crankcase 13c crank chamber 16 crank shaft 16c crank pin 16d counter weight 33 flywheel 39 drive gear 40 carrier member 41 tubular portion 43 window 45 bevel gear 48 power transmission mechanism 50, 250 driven gear 52 circlip 54 balancer weight 60 Start motor 62 Output gear (output gear)
65 Reduction gear section (reduction gear)
67 gear portion 68 one-way clutch 70 protrusion (detected portion)
71, 81 Sensor 250b Detected part

Claims (9)

A crankcase (11) having a crank chamber (13c) for receiving a crankpin (16c) of a crankshaft (16) and a counterweight (16d), and rotating in a direction opposite to the rotational direction of the crankshaft (16) In a balancer device of an internal combustion engine provided with a balancer weight (54),
The balancer device includes a drive gear (39) connected to the crankshaft (16) and rotating in the same direction as the crankshaft (16), and a power transmission mechanism (not shown) for transmitting rotational power of the drive gear (39). 48), a driven gear (50, 250) that receives power from the power transmission mechanism (48) and rotates in the opposite direction to the crankshaft (16), and the driven gear (50, 250) With a balancer weight (54),
The power transmission mechanism (48) comprises a carrier member (40) for transmitting power with the start motor (60) of the internal combustion engine via a gear portion (67) provided on the outer periphery, and the carrier member ( 40) rotatably supported on the drive gear (39) and the driven gear (50, 250), and between the carrier member (40) and the drive gear (39) And one-way clutch (68)
The carrier member (40) or the driven gear (250) has a detected portion (70, 250b),
A sensor (71, 81) for detecting the detected portion (70, 250b);
A balancer device for an internal combustion engine, which detects the phase of the carrier member (40) or the driven gear (250) based on the detection by the sensor (71, 81).   The carrier member (40) or the driven member by the starter motor (60) based on the phase of the carrier member (40) or the driven gear (250) detected based on the detection by the sensor (71, 81) The balancer device for an internal combustion engine according to claim 1, wherein the gear (250) is rotated to a predetermined phase.   The start motor (60) is driven so that the detected portion (70) of the carrier member (40) stops at the position of the sensor (71) immediately after the start of the internal combustion engine. The balancer apparatus for an internal combustion engine according to claim 2.   In the start motor (60), the carrier member (40) is engaged with the drive gear (39) via the one-way clutch (68) while the internal combustion engine is stopped, in the opposite direction to the rotational direction The balancer device according to claim 2 or 3, wherein the member (40) is driven to rotate, and the carrier member (40) is rotated to the predetermined phase.   The balancer device of an internal combustion engine according to any one of claims 1 to 4, wherein the rotational speed of the driven gear (50, 250) is the same as the rotational speed of the crankshaft (16).   A reduction gear (65) is provided between the output gear (62) of the starting motor (60) and the gear portion (67) of the carrier member (40). A balancer device for an internal combustion engine according to any one of the preceding claims.   The carrier member (40) includes windows (43) penetrating both side surfaces, and the bevel gear (45) is disposed with its teeth facing the windows (43). The balancer apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein   A balancer according to any one of the preceding claims, characterized in that the drive gear (39) is formed on the side of a flywheel (33) connected to the crankshaft (16). apparatus.   The carrier member (40) has a cylindrical portion (41) which accommodates the crank shaft (16) radially inward, and the driven gear (50, 250) radially outward of the cylindrical portion (41). The balancer device for an internal combustion engine according to any one of claims 1 to 8, wherein the cylindrical portion (41) is provided with a circlip (52) at the end of the cylindrical portion (41).

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