Engine unit and saddle-type vehicle mounted with the same

Abstract

To enhance connectivity of a harness connected to a position detection mechanism detecting a position of a movable sheave.SOLUTION: An engine unit 8 comprises a crankshaft 22, a case 2, and a continuously variable transmission 15. The case 2 includes a crankcase 21 supporting the crank shaft 22. The continuously variable transmission 15 is electronically controlled and housed within the case 2. The continuously variable transmission 15 has: a movable sheave 57 movable in a shaft direction of the crankshaft 22; and a position detection mechanism 100 which detects a position of the movable sheave 57. The position detection mechanism 100 has: a shaft 104 which is arranged to pass through the case 2 and rotates in response to a movement of the movable sheave 57; and a rotation sensor 102 which is arranged outside the case 2 and detects a rotation angle of the shaft 104. The position detection mechanism 100 detects the position of the movable sheave 57 based on the rotation angle of the shaft 104 detected by the rotation sensor 102.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an engine unit and a straddle-type vehicle equipped with an engine unit. [Background technology]

[0002] Conventionally, continuously variable transmissions that use an electric actuator to move a movable sheave are known. The continuously variable transmission disclosed in Patent Document 1 includes a non-contact position detection sensor that detects the axial position of the movable sheave. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-066434 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a position detection sensor that detects the axial position of the movable sheave is disposed inside the engine unit. If the position detection sensor is disposed inside the engine unit, the harness connected to the position detection sensor needs to be taken out from inside the engine unit to the outside, which reduces the connectivity of the harness.

[0005] An object of the invention is to improve the connectivity of a harness that is connected to a position detection mechanism that detects the position of a movable sheave. [Means for solving the problem]

[0006] An engine unit according to one aspect of the present invention includes a crankshaft, a case, and a continuously variable transmission. The case includes a crankcase that supports the crankshaft. The continuously variable transmission is electronically controlled and housed in the case. The continuously variable transmission includes a movable sheave that is movable in the axial direction of the crankshaft, and a position detection mechanism that detects the position of the movable sheave. The position detection mechanism includes a shaft that is disposed to pass through the case and rotates in response to movement of the movable sheave, and a rotation sensor that is disposed outside the case and detects the rotation angle of the shaft. The position detection mechanism detects the position of the movable sheave based on the rotation angle of the shaft detected by the rotation sensor.

[0007] In the engine unit according to this aspect, the position detection mechanism detects the position of the movable sheave by using a rotation sensor located outside the case to detect the rotation angle of a shaft that passes through the case and rotates in response to movement of the movable sheave. This improves the connectivity of the harness connected to the position detection mechanism and makes it less susceptible to heat generated by the engine compared to when the rotation sensor is located inside the case.

[0008] The case may include a belt chamber that houses a belt of the continuously variable transmission. The crankcase may include a crank chamber. The shaft may be arranged to pass through the belt chamber and the crank chamber. In this case, the shaft can be arranged in a position close to the crankshaft, which is expected to improve the accuracy of detecting the position of the movable sheave. Since the shaft can be arranged at the shortest distance to the movable sheave, the dimensions of the shaft can be reduced.

[0009] The case may further include a crankcase cover attached to the crankcase within the crankcase to separate the crankcase from the belt case. A portion of the movable sheave and the shaft may be disposed inside the crankcase cover. In this case, a portion of the position detection mechanism can be protected by the crankcase cover.

[0010] The shaft may include a cam that converts the axial linear motion of the movable sheave into rotational motion of the shaft. In this case, the use of a cam allows the position detection mechanism to be realized with an even simpler and less expensive configuration.

[0011] The continuously variable transmission may further include a sheave drive mechanism that moves the movable sheave in the axial direction. The movable sheave may include a boss portion extending in the axial direction. The sheave drive mechanism may include a drive member that is supported on the boss portion so as to be rotatable but immovable in the axial direction. The cam on the shaft may be engaged with the drive member. In this case, since the cam is engaged with the drive member that is positioned close to the rotation axis, improved accuracy in detecting the position of the movable sheave can be expected.

[0012] The position detection mechanism may further include a biasing member that biases the shaft in one of the rotation directions of the shaft, in which case the position detection mechanism can be realized with a simple and inexpensive configuration.

[0013] The position detection mechanism may further include a support member that supports the shaft. The case may include an opening that opens upward when the vertical direction when the continuously variable transmission is mounted on a vehicle is defined as the up-down direction, and in which the support member is disposed. In this case, the position detection mechanism can be configured to only receive thrust in the direction of gravity, which is expected to reduce the number of parts. Also, assembly of the position detection mechanism to the case becomes easier.

[0014] The shaft may have a first end and a second end located below the first end, and may be cantilevered at the first end by the support member. In this case, the number of parts can be reduced and the position detection mechanism can be realized with a simple and inexpensive configuration.

[0015] The support member may include a bushing disposed at the first end of the shaft. The bushing may extend along the shaft. In this case, tilting of the shaft relative to the support member can be suppressed.

[0016] A saddle-ride type vehicle according to another aspect of the present invention includes the engine unit described above. In this saddle-ride type vehicle, compared to a case in which the rotation sensor is disposed inside the case, the connection of the harness to the position detection mechanism can be improved and the vehicle is less susceptible to the effects of heat generated by the engine. [Effects of the Invention]

[0017] According to the present invention, it is possible to improve the connectivity of the harness connected to the position detection mechanism that detects the position of the movable sheave. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a left side view of the saddle-ride type vehicle. [Figure 2] FIG. 2 is a cross-sectional top view of the engine unit. [Figure 3] FIG. 2 is an enlarged view showing a primary pulley and a sheave drive mechanism. [Figure 4] FIG. 2 is an enlarged view showing a primary pulley and a sheave drive mechanism. [Figure 5] FIG. 4 is an enlarged view showing a secondary pulley and a centrifugal clutch. [Figure 6] FIG. 4 is an enlarged view showing a secondary pulley and a centrifugal clutch. [Figure 7] FIG. 2 is a side view of the engine unit 8. [Figure 8] FIG. 2 is a partial cross-sectional view of the periphery of a position detection mechanism. [Figure 9] FIG. 2 is a partial cross-sectional view of the periphery of a position detection mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0019] A saddle-riding vehicle according to an embodiment will now be described with reference to the drawings. FIG. 1 is a left side view of a saddle-riding vehicle 1 according to an embodiment. The saddle-riding vehicle 1 according to this embodiment is a scooter. As shown in FIG. 1, the saddle-riding vehicle 1 includes a body frame 2, a body cover 3, a front wheel 4, a rear wheel 5, a steering device 6, a seat 7, and an engine unit 8. In this embodiment, the up-down, front-rear, and left-right directions refer to the up-down, front-rear, and left-right directions as seen from a rider seated on the seat 7.

[0020] The body cover 3 covers the body frame 2. The steering device 6 is supported by the body frame 2 so as to be rotatable left and right. The steering device 6 includes a front fork 11, a steering shaft 12, and a handle member 13.

[0021] The front fork 11 rotatably supports the front wheel 4. The steering shaft 12 is connected to the front fork 11. The steering shaft 12 is supported by the body frame 2 so as to be rotatable left and right. The handle member 13 is connected to the steering shaft 12.

[0022] The seat 7 is disposed behind the handle member 13. The engine unit 8 is disposed below the seat 7. The engine unit 8 is supported by the body frame 2 so as to be able to swing up and down. The engine unit 8 rotatably supports the rear wheel 5. The engine unit 8 includes a case 9, an engine 14, and a continuously variable transmission 15.

[0023] The engine 14 and the continuously variable transmission 15 are disposed within the case 9. The case 9 includes a crankcase 21, a transmission case 48, and a crankcase cover 76, which will be described later. The continuously variable transmission 15 is disposed to the side of the engine 14. The continuously variable transmission 15 transmits driving force from the engine 14 to the rear wheels 5.

[0024] 2 is a cross-sectional top view of the engine unit 8. As shown in FIG. 2, the engine 14 includes a crankcase 21, a crankshaft 22, a cylinder body 23, a cylinder head 24, a piston 25, a connecting rod 26, and a valve train 27.

[0025] The crankshaft 22 is housed in the crankcase 21. The crankshaft 22 is rotatably supported by the crankcase 21 via bearings 28 and 29. The crankshaft 22 includes a first shaft end 22A and a second shaft end 22B. A continuously variable transmission 15 (an example of a continuously variable transmission) is connected to the first shaft end 22A. A generator 31 is connected to the second shaft end 22B.

[0026] The cylinder body 23 is connected to the crankcase 21. The cylinder head 24 is connected to the cylinder body 23. A connecting rod 26 and a piston 25 are disposed within the cylinder body 23. The piston 25 is connected to the crankshaft 22 via the connecting rod 26. An ignition device 32 is attached to the cylinder head 24. The valve train 27 includes a camshaft 33. A cam chain 34 is wound around the camshaft 33 and the crankshaft 22. The rotation of the crankshaft 22 is transmitted to the camshaft 33 via the cam chain 34, causing the camshaft 33 to rotate. As a result, intake valves and exhaust valves (not shown) of the engine 14 are driven by the valve train 27.

[0027] The continuously variable transmission 15 is an electronically controlled transmission, that is, the continuously variable transmission 15 is electrically controlled to change the gear ratio in response to a command signal from a controller (not shown).

[0028] As shown in FIG. 2, the continuously variable transmission 15 includes a crankshaft 22, a primary pulley 41, a secondary pulley 42, a belt 43, a sheave drive mechanism 44, a centrifugal clutch 45, an output shaft 46, a reducer 47, and a transmission case 48.

[0029] Primary pulley 41 is connected to crankshaft 22. Primary pulley 41 includes a V-shaped first groove 41A. Secondary pulley 42 is connected to rear wheel 5 via axle 49. Secondary pulley 42 includes a V-shaped second groove 42A.

[0030] The belt 43 is wound around the primary pulley 41 and the secondary pulley 42. The belt 43 has a trapezoidal cross section corresponding to the shapes of the first groove 41A and the second groove 42A. The secondary pulley 42 is connected to an output shaft 46 via a centrifugal clutch 45. The output shaft 46 is connected to an axle 49 via a reducer 47. The output shaft 46 is rotatably supported by a reducer case 51 (described later) via bearings 53 and 54. The axle 49 is rotatably supported by the reducer case 51 via bearings 55 and 56.

[0031] The reducer 47 includes a reducer case 51 and a gear 52. The reducer case 51 houses the gear 52. The gear 52 transmits the rotation of the output shaft 46 to the axle 49. Note that in FIG. 2, only the gear 52 out of the multiple gears of the reducer 47 is shown, and the other gears are omitted.

[0032] The transmission case 48 axially covers the primary pulley 41, the secondary pulley 42, the belt 43, the centrifugal clutch 45, and the output shaft 46.

[0033] The crankcase cover 76 is attached to the crankcase 21 inside the crankcase 21. The crankcase cover 76 separates a crank chamber C1 of the crankcase 21 from a belt chamber C2 in which the belt 43 is housed. In this embodiment, the crank chamber C1 is formed by the crankcase 21 and the crankcase cover 76, and the belt chamber C2 is formed by a portion of the crankcase 21, the crankcase cover 76, and the transmission case 48. In other words, a portion of the crankcase 21 and the crankcase cover 76 form part of the belt chamber C2.

[0034] The right side of the belt chamber C2 is defined by the right side of the crankcase 21 and the crankcase cover 76. The left side of the belt chamber C2 is defined by the transmission case 48. Note that the belt chamber C2 may be defined by the transmission case 48 and the crankcase cover 76, or may be defined by the transmission case 48 alone.

[0035] 3 and 4 are enlarged views showing the primary pulley 41 and the sheave drive mechanism 44. Fig. 5 is a partial enlarged view of Fig. 3. As shown in Figs. 3 and 4, the primary pulley 41 includes a first movable sheave 57 (an example of a movable sheave) and a first fixed sheave 58.

[0036] The first movable sheave 57 is supported so as to be movable in the axial direction of the crankshaft 22 (hereinafter simply referred to as the axial direction) of the crankshaft 22. The first movable sheave 57 is disposed axially inward (on the left side in FIG. 3) of the first fixed sheave 58.

[0037] The first moving sheave 57 is supported by the crankshaft 22 so as to be unable to rotate in the circumferential direction of the crankshaft 22. The first moving sheave 57 is fixed to the crankshaft 22 by a spline. The first moving sheave 57 rotates integrally with the crankshaft 22.

[0038] The first movable sheave 57 includes a first sheave portion 59 and a first boss portion 60. The first sheave portion 59 is disposed opposite the first fixed sheave 58. The first sheave portion 59 is fixed to the outer peripheral surface of the first boss portion 60. A first groove 41A is provided between the first sheave portion 59 and the first fixed sheave 58. The first boss portion 60 extends in the axial direction from the first sheave portion 59. The first boss portion 60 includes a first boss hole 61. The first boss hole 61 extends in the axial direction. The crankshaft 22 extends through the first boss hole 61.

[0039] The crankshaft 22 includes an outer shaft 62. The outer shaft 62 is attached to the outer peripheral surface of the first shaft end 22A. The first movable sheave 57 is fixed to the outer shaft 62 by a spline. The outer shaft 62 extends through a first boss hole 61. A first bushing 63 and a second bushing 64 are press-fitted into the first boss hole 61. The first bushing 63 and the second bushing 64 are formed of a sliding material. The first bushing 63 and the second bushing 64 are disposed between the inner peripheral surface of the first boss hole 61 and the outer peripheral surface of the outer shaft 62. As the first movable sheave 57 moves in the axial direction, the first bushing 63 and the second bushing 64 slide axially relative to the outer shaft 62. The first boss hole 61 is filled with a lubricant such as grease. The gap between the first boss portion 60 and the outer shaft 62 is sealed by oil seals 65 and 66.

[0040] The first fixed sheave 58 is fixed to the crankshaft 22. The first fixed sheave 58 is fixed to the crankshaft 22 by a nut 40. The first fixed sheave 58 is fixed to the crankshaft 22 so as to be immovable in the axial direction. The first fixed sheave 58 is fixed to the crankshaft 22 so as to be imrotatable relative to the crankshaft 22. The first fixed sheave 58 rotates integrally with the crankshaft 22.

[0041] The sheave drive mechanism 44 axially moves the first movable sheave 57. A portion of the sheave drive mechanism is disposed within the belt chamber C2. As shown in Fig. 2, the sheave drive mechanism 44 includes an electric actuator 67, a first drive member 68, and a second drive member 69 (an example of a drive member).

[0042] The electric actuator 67 is, for example, an electric motor. The electric actuator 67 may be an actuator other than an electric motor. The electric actuator 67 includes a rotating shaft 70. The rotating shaft 70 is connected to a first driving member 68 via a gear 71. The rotation of the rotating shaft 70 is transmitted to the first driving member 68 via the gear 71.

[0043] As shown in Figures 3 and 4, the first drive member 68 is disposed within the crank chamber C1. The first drive member 68 includes a first hole 72. The first hole 72 extends axially through the first drive member 68. The crankshaft 22 passes through the first hole 72. The first drive member 68 is supported by the crankshaft 22 via a bearing 50. The first drive member 68 is supported rotatably relative to the crankshaft 22. The first drive member 68 is supported so as to be immovable in the axial direction relative to the crankshaft 22.

[0044] The first driving member 68 includes a gear portion 73 and a feed screw portion 74. The gear portion 73 extends from the feed screw portion 74 in the radial direction of the crankshaft 22. The gear portion 73 meshes with a gear 71. The rotation of the rotary shaft 70 of the electric actuator 67 is transmitted to the gear portion 73 via the gear 71. This causes the first driving member 68 to rotate. The feed screw portion 74 extends in the axial direction from the gear portion 73. A first screw 75 is provided on the outer circumferential surface of the feed screw portion 74.

[0045] The crankcase cover 76 includes an opening 76A. The opening 76A is disposed facing the primary pulley 41. The second drive member 69 extends through the opening 76A of the crankcase 21. An oil seal 77 seals the gap between the second drive member 69 and the crankcase cover 76. The second drive member 69 is disposed across the crank chamber C1 and the belt chamber C2.

[0046] The second drive member 69 includes a second bore 78. The second bore 78 extends axially through the second drive member 69. The crankshaft 22 and the first boss portion 60 extend through the second bore 78.

[0047] The second drive member 69 is supported by the first boss portion 60 via a bearing 79. The second drive member 69 is rotatably supported by the first boss portion 60. The second drive member 69 is supported by the first boss portion 60 so as to be immovable in the axial direction. The second drive member 69 moves axially together with the first movable sheave 57. An oil seal 80 seals the gap between the second drive member 69 and the first boss portion 60. A second screw 81 is provided on the inner circumferential surface of the second drive member 69. The second screw 81 meshes with the first screw 75. When the first drive member 68 rotates, the second drive member 69 moves axially as shown in FIG. 4. This causes the first movable sheave 57 to move axially. The second screw 81 is disposed within the crank chamber C1.

[0048] 5 and 6 are enlarged views showing the secondary pulley 42 and the centrifugal clutch 45. The secondary pulley 42 includes a second fixed sheave 82 and a second movable sheave 83. The second fixed sheave 82 is supported rotatably on the output shaft 46. The second fixed sheave 82 is supported immovably in the axial direction on the output shaft 46.

[0049] The second fixed sheave 82 includes a second sheave portion 84 and a second boss portion 85. The second sheave portion 84 is disposed opposite the second movable sheave 83. A second groove 42A is provided between the second sheave portion 84 and the second movable sheave 83. The second boss portion 85 extends in the axial direction from the second sheave portion 84. The second boss portion 85 includes a second boss hole 86. The second boss hole 86 extends in the axial direction through the second boss portion 85.

[0050] The output shaft 46 is rotatably supported by the transmission case 48 via a bearing 95. The output shaft 46 extends through the second boss hole 86. A bushing 91 is press-fitted into the second boss hole 86. The bushing 91 is made of a sliding material. The bushing 91 is disposed between the inner peripheral surface of the second boss hole 86 and the outer peripheral surface of the output shaft 46.

[0051] The second boss portion 85 is rotatably supported on the output shaft 46 by a bushing 91 and a bearing 92. A lubricant such as grease is filled inside the second boss hole 86. An oil seal 93 seals the gap between the second boss portion 85 and the output shaft 46.

[0052] The second movable sheave 83 is disposed axially outward (to the right in FIG. 5) relative to the second fixed sheave 82. The second movable sheave 83 is supported non-rotatably relative to the second boss portion 85. The second movable sheave 83 rotates integrally with the second fixed sheave 82. The second movable sheave 83 is supported axially movably relative to the second boss portion 85. For example, the second movable sheave 83 is fixed to the second boss portion 85 by a spline. A spring 87 is disposed between the second movable sheave 83 and the centrifugal clutch 45. The spring 87 biases the second movable sheave 83 toward the second fixed sheave 82.

[0053] As shown in Fig. 5, when the vehicle speed is lower than a predetermined coupling speed, the centrifugal clutch 45 is in a disengaged state that disconnects the continuously variable transmission 15 from the rear wheels 5. As shown in Fig. 6, when the vehicle speed is equal to or higher than the coupling speed, the centrifugal clutch 45 is in an engaged state that connects the continuously variable transmission 15 to the rear wheels 5.

[0054] The centrifugal clutch 45 includes a drive plate 88, a clutch shoe 89, and a clutch outer 90. The drive plate 88 is fixed to the second boss portion 85. The drive plate 88 rotates integrally with the second boss portion 85.

[0055] The clutch shoe 89 is connected to the drive plate 88. The clutch shoe 89 rotates integrally with the drive plate 88. The clutch shoe 89 is supported so as to be movable in the radial direction relative to the drive plate 88. The clutch shoe 89 is biased radially inward by a clutch spring (not shown).

[0056] The clutch outer 90 is fixed to the output shaft 46 by a nut 94. The clutch outer 90 rotates integrally with the output shaft 46. The clutch outer 90 covers the clutch shoes 89 in the radial direction.

[0057] When the vehicle speed is slower than a predetermined engagement speed, the clutch shoe 89 is separated from the clutch outer 90 by the biasing force of the clutch spring. Therefore, the centrifugal clutch 45 is in a disengaged state, and the rotation of the secondary pulley 42 is not transmitted to the output shaft 46. When the vehicle speed is equal to or higher than the engagement speed, the clutch shoe 89 moves radially outward due to centrifugal force against the biasing force of the clutch spring. As a result, the clutch shoe 89 comes into contact with the clutch outer 90, and the centrifugal clutch 45 enters an engaged state. When the centrifugal clutch 45 is in an engaged state, the rotation of the secondary pulley 42 is transmitted to the output shaft 46 via the drive plate 88, the clutch shoe 89, and the clutch outer 90.

[0058] Fig. 7 is a left side view of the engine unit 8. As shown in Fig. 7, the continuously variable transmission 15 includes a position detection mechanism 100. The position detection mechanism 100 is a mechanism for detecting the axial position of the first movable sheave 57.

[0059] 8 and 9 are partial cross-sectional views of the periphery of the position detection mechanism 100. The position detection mechanism 100 includes a rotation sensor 102, a shaft 104, a support member 106, and a torsion spring 108 (an example of a biasing member). The position detection mechanism 100 detects the position of the first movable sheave 57 based on the rotation angle of the shaft 104 detected by the rotation sensor 102.

[0060] The rotation sensor 102 is disposed outside the case 9. In this embodiment, the rotation sensor 102 is disposed outside the crankcase 21. The rotation sensor 102 is exposed from the crankcase 21. The rotation sensor 102 is disposed above an opening 9a provided in the case 9. The opening 9a opens upward. The opening 9a is formed in the crankcase 21. The opening 9a is formed in a portion of the crankcase 21 that constitutes a part of the belt chamber C2. In other words, the opening 9a is connected to the belt chamber C2. The opening 9a may be provided in the transmission case 48.

[0061] The rotation sensor 102 is, for example, a potentiometer. The rotation sensor 102 is connected to the shaft 104 and detects the rotation angle of the shaft 104. The rotation sensor 102 detects the rotation angle of the shaft 104 and outputs a signal according to the detection result to a controller (not shown).

[0062] The shaft 104 rotates in response to the movement of the first movable sheave 57. As shown in FIGS. 7 and 8, the shaft 104 extends substantially in the vertical direction. In FIG. 7, the central axis of the shaft 104 is indicated by a dashed line. The shaft 104 is disposed so as to pass through the crank chamber C1 and the belt chamber C2 of the crankcase 21. The shaft 104 is disposed across the crank chamber C1 and the belt chamber C2. In other words, the shaft 104 extends across the crank chamber C1 and the belt chamber C2. An upper portion of the shaft 104 is disposed within the belt chamber C2, and a lower portion of the shaft 104 is disposed within the crank chamber C1. The shaft 104 is disposed so as to pass through the belt chamber C2 and the crank chamber C1 through the opening 9a.

[0063] The shaft 104 is slightly inclined with respect to the vertical direction in a side view of the vehicle. The shaft 104 includes a first end 110, a second end 111, and a cam 112. The first end 110 is the upper end of the shaft 104. The first end 110 is connected to the rotation sensor 102. The first end 110 is disposed inside the opening 9a. The first end 110 is disposed within the belt chamber C2. The shaft 104 is cantilevered by the support member 106 at the first end 110. An E-ring 114 is disposed on the outer circumferential surface of the first end 110 of the shaft 104. The shaft 104 is prevented from coming off the support member 106 by the E-ring 114 and a washer 116 disposed adjacent to the E-ring 114.

[0064] As shown in Fig. 9, the shaft 104 is disposed inside the crankcase cover 76. When viewed from the vehicle front-rear direction, the shaft 104 overlaps with the crankcase cover 76. As shown in Figs. 3 and 4, a portion of the first moving sheave 57 is disposed inside the crankcase cover 76. When viewed from the vehicle front-rear direction, the first moving sheave 57 overlaps with the crankcase cover 76.

[0065] The second end 111 is located lower than the first end 110. The second end 111 is located further rearward of the vehicle than the first end 110. Therefore, the shaft 104 extends downward and rearward from the first end 110. The second end 111 is located lower than the support member 106. The second end 111 is located within the crank chamber C1.

[0066] The cam 112 converts the axial linear motion of the first movable sheave 57 into the rotational motion of the shaft 104. In this embodiment, the cam 112 converts the axial linear motion of the first movable sheave 57 into the rotational motion of the shaft 104 via the second driving member 69. The cam 112 is engaged with the second driving member 69. The cam 112 is disposed at the second end 111. The cam 112 is fixed to the outer peripheral surface of the second end 111. The cam 112 is fixed to the shaft 104 at the second end 111 by press fitting. The cam 112 rotates integrally with the shaft 104. The cam 112 extends radially from the outer peripheral surface of the second end 111.

[0067] The cam 112 faces the locking protrusion 69a of the second driving member 69 in the axial direction. The locking protrusion 69a protrudes radially outward from the crankshaft 22 on the outer peripheral surface of the second driving member 69. Rotation of the locking protrusion 69a around the crankshaft 22 is restricted by a pair of restricting portions 107 provided inside the crankcase 21. The tip of the cam 112 has a shape that curves in the direction toward the locking protrusion 69a. The cam 112 is disposed to the left of the locking protrusion 69a. The cam 112 is locked by the locking protrusion 69a. The tip of the cam 112 is constantly in contact with the locking protrusion 69a due to the biasing force of the torsion spring 108.

[0068] The support member 106 rotatably supports the shaft 104. The support member 106 is fixed to the crankcase 21. The support member 106 is disposed across the crank chamber C1 and the belt chamber C2.

[0069] The support member 106 includes a tubular portion 120, a flange portion 122, an impregnated bushing 124 (an example of a bushing), and an oil seal 126. The tubular portion 120 extends substantially in the vertical direction. The tubular portion 120 passes through the opening 21a. The tubular portion 120 has a cylindrical shape, and the shaft 104 passes through it.

[0070] The cylindrical portion 120 includes a first hole 120a and a second hole 120b. The first end 110 of the shaft 104 is disposed in the first hole 120a. The E-ring 114 and the washer 116 are disposed in the first hole 120a.

[0071] The second hole 120b is disposed below the first hole 120a. The vertical dimension of the second hole 120b is larger than the vertical dimension of the first hole 120a. The inner diameter of the second hole 120b is smaller than the inner diameter of the first hole 120a. A washer 116 and an E-ring 114 are disposed in a step formed by the first hole 120a and the second hole 120b.

[0072] The flange portion 122 is disposed at the upper end of the cylindrical portion 120. The outer diameter of the flange portion 122 is larger than the inner diameter of the opening 32a. The flange portion 122 is disposed on the upper end surface of the opening 21a of the crankcase 21.

[0073] The impregnated bushing 124 has a cylindrical shape. The impregnated bushing 124 is disposed at the first end 110. The impregnated bushing 124 is disposed in the second hole 120b of the tubular portion 120. The impregnated bushing 124 is fixed by press-fitting. The impregnated bushing 124 extends along the shaft 104. The shaft 104 passes through the impregnated bushing 124, and prevents the shaft 104 from tilting relative to the support member 106.

[0074] The oil seal 126 is disposed in the second hole 120b. The oil seal 126 is disposed between the washer 116 and the impregnated bushing 124.

[0075] The torsion spring 108 biases the shaft 104 in one direction of rotation of the shaft 104. The torsion spring 108 biases the shaft 104 in the axial direction so that the tip of the cam 112 always contacts the locking projection 69a. The torsion spring 108 is disposed below the support member 106. The torsion spring 108 is disposed radially outward of the shaft 104. The torsion spring 108 is connected to the cylindrical portion 120 of the support member 106 and the shaft 104.

[0076] In the continuously variable transmission 15 described above, when the vehicle speed is equal to or higher than the coupling speed, the centrifugal clutch 45 is engaged. As a result, the rotation of the crankshaft 22 is transmitted to the rear wheel 5 via the primary pulley 41, the belt 43, the secondary pulley 42, the centrifugal clutch 45, the output shaft 46, the reducer 47, and the axle 49. As a result, the saddle-type vehicle 1 travels.

[0077] Furthermore, the gear ratio of the continuously variable transmission 15 is electrically controlled by moving the first movable sheave 57 with the sheave drive mechanism 44. The gear ratio of the continuously variable transmission 15 means the ratio of the rotational speed of the crankshaft 22 to the rotational speed of the output shaft 46.

[0078] Specifically, when the electric actuator 67 rotates the first drive member 68 in a certain direction, the second drive member 69 moves axially outward as shown in FIG. 4 . This causes the first movable sheave 57 to move axially outward together with the second drive member 69. As the second drive member 69 moves axially outward, the tip of the cam 112 is pressed against the locking protrusion 69a of the second drive member 69, causing the cam 112 to rotate against the biasing force of the torsion spring 108, thereby rotating the shaft 104. When the first movable sheave 57 moves axially outward, the width of the first groove 41A between the first movable sheave 57 and the first fixed sheave 58 decreases. This increases the diameter of the portion of the belt 43 wound around the primary pulley 41 (hereinafter referred to as the “first winding diameter”). As the first winding diameter increases, the diameter of the portion of the belt 43 wound around the secondary pulley 42 (hereinafter referred to as the “second winding diameter”) decreases. As a result, the speed change ratio becomes smaller. In this case, as shown in Fig. 6, the second movable sheave 83 moves axially outward against the biasing force of the spring 87, and the width of the second groove 42A increases.

[0079] When the electric actuator 67 rotates the first drive member 68 in the reverse direction, the second drive member 69 moves axially inward, as shown in FIG. 4. This causes the first movable sheave 57 to move axially inward together with the second drive member 69. As the second drive member 69 moves axially inward, the biasing force of the torsion spring 108 causes the cam 112 to rotate in a direction that presses the locking protrusion 69a of the second drive member 69, causing the shaft 104 to rotate in the biasing direction of the torsion spring 108. When the first movable sheave 57 moves axially inward, the width of the first groove 41A between the first movable sheave 57 and the first fixed sheave 58 increases. This reduces the first winding diameter. When the first winding diameter decreases, the second winding diameter increases. This increases the gear ratio. In this case, as shown in FIG. 5, the second movable sheave 83 moves axially inward due to the biasing force of the spring 87, and the width of the second groove 42A becomes smaller.

[0080] In the engine unit 8 of the saddle-ride type vehicle 1 having the above-described configuration, the position detection mechanism 100 detects the position of the first moving sheave 57 by using a rotation sensor 102 arranged outside the case 9 to detect the rotation angle of the shaft 104, which passes through the case 9 and rotates in response to movement of the first moving sheave 57. This improves the connectivity of the harness connected to the position detection mechanism 100 and makes it less susceptible to the effects of heat generated by the engine 14, compared to when the rotation sensor 102 is arranged inside the case 9.

[0081] Furthermore, because the shaft 104 is disposed so as to pass through the belt chamber C2 and the crank chamber C1, it is possible to dispose the shaft 104 in a position close to the crankshaft 22, which is expected to improve the accuracy of detecting the position of the first moving sheave 57, and it is also possible to dispose the shaft 104 in the shortest distance to the first moving sheave 57, thereby reducing the dimensions of the shaft 104. Furthermore, because the sheave drive mechanism 44 is disposed in the crank chamber C1, it is possible to suppress a decrease in the lubrication performance of the sheave drive mechanism 44 compared to when the sheave drive mechanism 44 is disposed in the belt chamber C2.

[0082] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0083] The straddle-type vehicle 1 is not limited to a scooter, but may be other types of vehicles such as a street type, an off-road type, or a moped. The configuration of the continuously variable transmission 15 is not limited to that of the above embodiment and may be modified. The process for controlling the gear ratio of the continuously variable transmission 15 is not limited to that of the above embodiment and may be modified. [Explanation of symbols]

[0084] 1: saddle-ride type vehicle, 2: case, 8: engine unit, 15: continuously variable transmission, 21: crankcase, 21a: opening, 22: crankshaft, 44: sheave drive mechanism, 57: first movable sheave, 60: first boss portion, 69: second drive member, 76: crankcase cover, 100: position detection mechanism, 102: rotation sensor, 104: shaft, 106: support member, 108: torsion spring, 110: first end, 111: second end, 112: cam, 124: impregnated bushing, C1: crankcase, C2: belt case

Claims

1. The crankshaft, a case including a crankcase supporting the crankshaft; an electronically controlled continuously variable transmission housed in the case; Equipped with the continuously variable transmission includes a movable sheave that is movable in the axial direction of the crankshaft, and a position detection mechanism that detects a position of the movable sheave, The position detection mechanism includes a shaft that is disposed to pass through the case and rotates in response to movement of the movable sheave, and a rotation sensor that is disposed outside the case and detects a rotation angle of the shaft, and detects the position of the movable sheave based on the rotation angle of the shaft detected by the rotation sensor. Engine unit.

2. the case includes a belt chamber that accommodates a belt of the continuously variable transmission, The crankcase includes a crank chamber, The shaft is disposed so as to pass through the belt chamber and the crank chamber. The engine unit according to claim 1 .

3. The case further includes a crankcase cover attached to the crankcase within the crankcase and separating the crankcase from the belt case, a portion of the movable sheave and the shaft are disposed inside the crankcase cover; 3. The engine unit according to claim 2.

4. The engine unit according to claim 1 , wherein the shaft includes a cam that converts the axial linear motion of the movable sheave into rotational motion of the shaft.

5. The continuously variable transmission further includes a sheave drive mechanism that moves the movable sheave in the axial direction, the movable sheave includes a boss portion extending in the axial direction, the sheave drive mechanism includes a drive member supported on the boss portion so as to be rotatable and immovable in the axial direction, The cam on the shaft is locked to the drive member.

5. The engine unit according to claim 4.

6. the position detection mechanism further includes a biasing member that biases the shaft in one rotation direction of the shaft. The engine unit according to claim 1 .

7. the position detection mechanism further includes a support member that supports the shaft; the case is open upward when the vertical direction in a state in which the continuously variable transmission is mounted on a vehicle is defined as the up-down direction, and includes an opening in which the support member is disposed. The engine unit according to claim 1 .

8. The shaft includes a first end and a second end located below the first end, and is cantilevered at the first end by the support member.

8. An engine unit according to claim 7.

9. the support member includes a bushing disposed on the first end of the shaft; The bushing extends along the shaft.

9. An engine unit according to claim 8.

10. A straddle-type vehicle comprising the engine unit according to any one of claims 1 to 9.

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