Power unit

Abstract

Provided is a power unit capable of preventing an increase in size even when a clutch mechanism and an idler gear are applied thereto. A power unit (P) has a motive power source (M), a clutch mechanism (CL) for adjusting the volume of rotational motive power transmitted from the motive power source (M) to a transmission mechanism (TM), and an output member (17) supported by an output shaft (81) of the transmission mechanism (TM). At positions not overlapping with an axis (JM) of the motive power source (M) when viewed in the axial direction, the output member (17) is disposed on one side in the width direction of the power unit (P) and the clutch mechanism (CL) is disposed on the other side in the width direction. Disposed between the motive power source (M) and the clutch mechanism (CL) in the width direction of the power unit (P) is an idler gear (60) for transmitting the rotational motive power to the clutch mechanism (CL).

Description

Power unit

[0001] The present invention relates to a power unit, and particularly to a power unit provided with a clutch mechanism for disconnecting and connecting the transmission of rotational power between a power source and a transmission mechanism.

[0002] Conventionally, as a drive source for motorcycles and the like, there is known a power unit configured to transmit the rotational power of a power source such as a motor to an output shaft to which a drive sprocket is fixed via a plurality of gears.

[0003] Patent Document 1 discloses a power unit configured to transmit the rotational power transmitted to an output gear fixed to the rotation shaft of a motor to an output shaft to which a drive sprocket is fixed via an idler gear (counter gear).

[0004] International Publication No. 2020 / 137053

[0005] However, the power unit of Patent Document 1 does not include a transmission mechanism and a clutch mechanism, and it is necessary to cope with the adjustment of motor output and the adjustment of driving force transmission force only by the motor and the transmission mechanism, and there is a limit to the adjustable capacity. Also, even when applying a transmission mechanism, a clutch mechanism, and an idler gear to solve that problem, Patent Document 1 has not considered a layout that can suppress the enlargement of the power unit.

[0006] An object of the present invention is to provide a power unit that solves the problems of the above prior art and can suppress enlargement even when applying a transmission mechanism, a clutch mechanism, and an idler gear.

[0007] To achieve the above objective, the present invention provides a power unit (P) having a power source (M), a clutch mechanism (CL) for adjusting the capacity of rotational power transmitted from the power source (M) to a transmission mechanism (TM), and an output member (17) supported on the output shaft (81) of the transmission mechanism (TM), wherein the output member (17) is positioned on one side in the width direction of the power unit (P) at a position that does not overlap with the rotation shaft (JM) of the power source (M) in an axial view, and the clutch mechanism (CL) is positioned on the other side in the width direction, and an idler gear (60) for transmitting the rotational power to the clutch mechanism (CL) is disposed between the power source (M) and the clutch mechanism (CL) in the width direction of the power unit (P).

[0008] Furthermore, a second characteristic of the clutch mechanism (CL) is that it is located below the power source (M).

[0009] Furthermore, a flywheel (52) is attached to the rotating shaft (JM) of the power source (M), and the idler gear (60) is disposed between the flywheel (52) and the clutch mechanism (CL) in the axial direction of the rotating shaft (JM). A third feature is that, in an axial view, the bearing portion (61) of the flywheel (52) and the idler gear (60) overlap.

[0010] Furthermore, the idler gear (60) is cantilevered, and a fourth feature is that its gear portion is positioned closer to the flywheel (52).

[0011] Furthermore, a fifth feature is that, in an axial view, at least a portion of the idler gear (60) overlaps with the clutch mechanism (CL).

[0012] Furthermore, the idler gear (60) is provided with at least one through hole (63), and a sixth feature is that, in an axial view of the idler gear (60), at least a part of the bearing retaining member (62) that fixes the bearing portion (61) overlaps with the through hole (63).

[0013] Furthermore, a seventh feature is that the device comprises a first cover (24) that covers the idler gear (60) and a second cover (25) that is separate from the first cover (24) and covers the clutch mechanism (CL), and the rotating shaft (60a) of the idler gear (60) is pivotally supported by the first cover (24).

[0014] Furthermore, a eighth feature is that the output member (17) and the clutch mechanism (CL) overlap in an axial view of the output shaft (81).

[0015] According to the first feature, in a power unit (P) having a power source (M), a clutch mechanism (CL) for adjusting the capacity of rotational power transmitted from the power source (M) to a transmission mechanism (TM), and an output member (17) supported on the output shaft (81) of the transmission mechanism (TM), the output member (17) is positioned on one side in the width direction of the power unit (P) at a position that does not overlap with the rotation shaft (JM) of the power source (M) in an axial view, and the clutch mechanism (CL) is positioned on the other side in the width direction, and an idler gear (60) is disposed between the power source (M) and the clutch mechanism (CL) in the width direction of the power unit (P) to transmit the rotational power to the clutch mechanism (CL). As a result, by distributing the output member, idler gear and clutch mechanism to one side and the other side in the width direction, while positioning the clutch mechanism at a position offset perpendicular to the axial direction of the power source, it becomes possible to arrange each component in a balanced and compact manner.

[0016] According to the second feature, since the clutch mechanism (CL) is located below the power source (M), it is possible to arrange each component in a balanced and compact manner.

[0017] According to the third feature, a flywheel (52) is attached to the rotating shaft (JM) of the power source (M), and the idler gear (60) is disposed between the flywheel (52) and the clutch mechanism (CL) in the axial direction of the rotating shaft (JM). In an axial view, the flywheel (52) and the bearing portion (61) of the idler gear (60) overlap, allowing the idler gear to be compactly installed.

[0018] According to the fourth feature, the idler gear (60) is cantilevered, and its gear portion is positioned closer to the flywheel (52). By cantilevering the idler gear, it can be arranged compactly in an axial view.

[0019] According to the fifth feature, in an axial view, at least a portion of the idler gear (60) overlaps with the clutch mechanism (CL), thus suppressing the increase in size of the power unit caused by providing the idler gear.

[0020] According to the sixth feature, the idler gear (60) is provided with at least one through hole (63), and in an axial view of the idler gear (60), at least a part of the bearing retaining member (62) that fixes the bearing portion (61) overlaps with the through hole (63). This makes it possible to access the bearing retaining member from the through hole provided in the idler gear, thereby improving the ease of assembly of the power unit.

[0021] According to the seventh feature, the device comprises a first cover (24) that covers the idler gear (60) and a second cover (25) that is configured separately from the first cover (24) and covers the clutch mechanism (CL). The rotating shaft (60a) of the idler gear (60) is pivotally supported by the first cover (24). By configuring the first cover and the second cover as separate components and pivotally supporting the rotating shaft of the idler gear in the first cover, the cover can be made smaller and the assembly of the idler gear can be improved.

[0022] According to the eighth feature, the output member (17) and the clutch mechanism (CL) overlap in an axial view of the output shaft (81), which allows for miniaturization of the power unit.

[0023] Figure 2 is a right side view of an electric motorcycle to which a power unit according to one embodiment of the present invention is applied. Figure 2 is a left side view of the electric motorcycle. Figure 2 is a partially enlarged view. Figure 3 is a perspective view of the power unit from the right rear. Figure 4 is a right side view of the power unit. Figure 5 is a right side view showing the power unit with the second cover removed. Figure 5 is a cross-sectional view taken along line VII-VII. Figure 6 is a right side view showing the power unit with the first cover removed. Figure 7 is a cross-sectional view taken along line IX-IX.

[0024] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a right side view of an electric motorcycle 1 to which a power unit P according to one embodiment of the present invention is applied. Figure 2 is a left side view of the electric motorcycle 1, and Figure 3 is a partially enlarged view of Figure 2. The electric motorcycle 1 is a saddle-type vehicle to which the rotational power of a power unit P, which is powered by a motor M, is transmitted to the rear wheel WR via a drive chain 15 wrapped around a drive sprocket 17 on the left side in the vehicle width direction.

[0025] A head pipe F1, which pivotally supports a steering stem (not shown), is connected to the front end of the main frame F2 that constitutes the vehicle frame F. A top bridge 4 and a bottom bridge 3, which support a pair of left and right front forks 14, are fixed to the top and bottom of the steering stem. The front wheel WF is pivotally supported at the lower end of the front fork 14. A steering handle 5 is attached to the top of the top bridge 4. A front fender 2 is attached to the front fork 14, covering the front and upper part of the front wheel WF.

[0026] A hanger frame F3, which supports the lower part of the power unit P, is connected to the lower part of the main frame F2. A battery B is located in front of the power unit P. The lower parts of the battery B and the power unit P are covered by an underguard 13. A shift pedal 16 is pivotally supported on the left side of the power unit P.

[0027] A pivot frame F4 is connected to the lower part of the main frame F2, which extends downward and rearward from the head pipe F1. The pivot frame F4 has a pivot 11 that pivotally supports the swingarm 8. The swingarm 8, which pivotally supports the rear wheel WR, is suspended from the vehicle frame F by a rear cushion 9. The brake pedal 12 is pivotally supported on the right side of the pivot frame F4 in the vehicle width direction. A rear fender 7 is attached to the rear of the main frame F2, which supports the seat 6 and covers the area above and behind the rear wheel WR.

[0028] Referring to Figure 3, a motor cover 21 is attached to the left casing 20 of the power unit P, covering the motor M. Below the motor cover 21, the output shaft 81 of the power unit P protrudes, and a drive sprocket 17, which serves as an output member, is supported on the output shaft 81 via splines.

[0029] Figure 4 is a perspective view of the power unit P viewed from the right rear. Figure 5 is a right side view of the power unit P, and Figure 6 is a right side view showing the power unit P in Figure 5 with the second cover 25 removed. The same reference numerals indicate the same or equivalent parts. The power unit P is configured such that a left casing 20 and a right casing 22 are fastened together by fastening members. The left casing 20 is provided with a connector support portion 30 that supports a connector 31 for supplying power to the motor M. The right casing 22 is fitted with a base cover 23 that covers the opening of the right casing 22, a first cover 24 that covers the opening of the base cover 23, and a second cover 25 that covers the opening of the first cover 24, each attached by multiple bolts. The connector 31 is connected to a first cable and a second cable (not shown) that lead to the battery B. The connector connection portion 30 is positioned forward of the rear end position E of the power unit hanger 32 in the vehicle's longitudinal direction.

[0030] The second cover 25, which covers the clutch mechanism CL, is attached to the first cover 24 by three first bolts B1 and three second bolts B2. Here, the second bolts B2 are fastened to the first cover 24, while the first bolts B1 pass through the first cover 24 and are fastened to the base cover 23. In other words, the first bolts B1 are structured to fasten both the second cover 25 and the first cover 24 together to the base cover 23.

[0031] The first cover 24 is attached to the base cover 23 by eight third bolts B3 and three first bolts B1. The base cover 23 is attached to the right casing 22 by several fourth bolts B4, etc. Clutch spring bolts 41 that support the clutch springs are visible through six circular holes in the pressure plate 40 of the clutch mechanism CL, which is covered by the second cover 25. The bearing 43 fitted to the back side of the second cover 24 pivotally supports the end of the main shaft of the transmission mechanism (see Figure 7).

[0032] Figure 7 is a cross-sectional view taken along line VII-VII of Figure 5. Figure 8 is a right side view showing the power unit P of Figure 6 with the first cover 24 removed, and Figure 9 is a cross-sectional view taken along line IX-IX of Figure 7. The same reference numerals indicate the same or equivalent parts.

[0033] The power unit P according to this embodiment includes a transmission mechanism TM as a stepped transmission and a clutch mechanism CL that disconnects and reconnects the rotational power transmitted from the motor M to the transmission mechanism TM. A large-diameter flywheel 52 and a small-diameter output gear 50 are fixed to the rotating shaft JM of the motor M. The right end of the rotating shaft JM in the vehicle width direction is rotatably supported by a bearing 51 fitted to the base cover 23.

[0034] An idler gear 60 meshes with the output gear 50. The idler gear 60 is cantilevered by two bearings 61 fitted into the base cover 23. The bearings 61 are held in place by the base cover 23 by thin plate-shaped bearing retaining members 62. Eight through holes 63 are formed in the idler gear 60.

[0035] A large-diameter primary driven gear 70 meshes with the idler gear 60. The primary driven gear 70 is fixed to a clutch housing 45 that houses a plurality of friction plates 44. The clutch mechanism CL transmits the rotational power transmitted to the primary driven gear 70 to the main shaft 80 of the transmission mechanism TM when frictional force is generated on the friction plates 44. As described above, the right end of the main shaft 80 in the vehicle width direction is rotatably supported by a bearing 43 that fits into the second cover 25.

[0036] Inside the main shaft 80 is a push rod 47 that slides in response to the hydraulic pressure generated in the clutch release cylinder 48 when the driver operates the clutch. The rotational power transmitted to the main shaft 80 is transmitted to the output shaft 81, which acts as a sub-shaft of the transmission mechanism TM, via a predetermined pair of transmission gears.

[0037] The power unit P according to this embodiment is characterized in that the drive sprocket 17 is positioned on one side in the width direction of the power unit P at a position that does not overlap with the rotation axis JM of the motor M in an axial view, and the clutch mechanism CL is positioned on the other side in the width direction. Furthermore, an idler gear 60 that transmits rotational power to the clutch mechanism CL is positioned between the motor M and the clutch mechanism CL in the width direction of the power unit P. As a result, by distributing the drive sprocket 17, idler gear 60 and clutch mechanism CL to one side and the other side in the width direction, it becomes possible to arrange each component in a balanced and compact manner.

[0038] Furthermore, a flywheel 52 is attached to the rotating shaft JM of the motor M, and the idler gear 60 is positioned between the flywheel 52 and the clutch mechanism CL in the axial direction of the rotating shaft JM, so that the rotating shaft 60a of the flywheel 52 and the rotating shaft 60a of the idler gear 60 overlap in an axial view. This makes it possible to compactly arrange the idler gear 60. Also, since at least a part of the idler gear 60 overlaps with the clutch mechanism CL in an axial view, it is possible to suppress the increase in size of the power unit P caused by providing the idler gear 60.

[0039] Furthermore, in an axial view of the idler gear 60, at least a portion of the bearing retaining member 62 that fixes the bearing 61 is configured to overlap with the through hole 63. More specifically, the bolt 62a for fixing the bearing retaining member 62 to the base cover 23 is configured to face the through hole 63 in an axial view. This makes it possible to access the bolt 62a for fixing the bearing retaining member 62 through the through hole 63, thereby improving the ease of assembly of the power unit P.

[0040] Furthermore, by constructing the first cover 24 and the second cover 25 as separate components and supporting the rotating shaft 60a of the idler gear 60 on the first cover 24, each cover can be miniaturized and the ease of assembly of the idler gear 60 can be improved. In addition, since the drive sprocket 17 and the clutch mechanism CL are configured to overlap in an axial view of the output shaft 81, the power unit P can be further miniaturized.

[0041] As shown in Figure 7, a PDU (Power Delivery Unit) 53 is housed in a position slightly to the left in the vehicle width direction of the motor M. The relationship between the vehicle width direction distance W1 between the left end of the clutch release cylinder 48 and the right end of the second cover 25, the vehicle width direction distance W2 between the left end of the gear portion of the idler gear 60 and the right end of the second cover 25, and the vehicle width direction distance W3 between the left end of the gear portion of the idler gear 60 and the right end of the first cover 24 is W1 > W2 > W3.

[0042] Referring to Figures 8 and 9, the rotating shaft JM of the motor M, the rotating shaft 60a of the idler gear 60, and the main shaft 80 of the transmission mechanism TM are arranged in the order of rotating shaft JM, main shaft 80, and rotating shaft 60a from the front of the power unit P, and in the order of rotating shaft JM, rotating shaft 60a, and main shaft 80 from above the power unit P. Furthermore, the longitudinal distance X1 between the center M1 of the rotating shaft JM and the center M2 of the rotating shaft 60a is set to be greater than the longitudinal distance X2 between the center M1 of the rotating shaft JM and the center M3 of the main shaft 80. In addition, the relationship between the axial distance L1 between the center M1 of the rotating shaft JM and the center M2 of the rotating shaft 60a, the axial distance L2 between the center M2 of the rotating shaft 60a and the center M3 of the main shaft 80, and the axial distance L3 between the center M1 of the rotating shaft JM and the center M3 of the main shaft 80 is L1 < L2 < L3. The relative positions of the rotating axis JM, the main spindle 80, and the rotating axis 60a may be inverted vertically or horizontally.

[0043] As described above, in the power unit P according to the present invention, the power unit P has a motor M, a clutch mechanism CL that adjusts the capacity of rotational power transmitted from the motor M to the transmission mechanism TM, and a drive sprocket 17 fixed to the output shaft 81 of the transmission mechanism TM, the drive sprocket 17 is positioned on one side in the width direction of the power unit P at a position that does not overlap with the rotation axis JM of the motor M in an axial view, and the clutch mechanism CL is positioned on the other side in the width direction, and an idler gear 60 is positioned between the output gear 50 of the motor M and the clutch mechanism CL in the width direction of the power unit P. Therefore, by positioning the clutch mechanism CL below the motor M and distributing the drive sprocket 17, idler gear 60 and clutch mechanism CL to one side and the other side in the width direction, it is possible to arrange each component in a balanced and compact manner.

[0044] The aspects of the electric two-wheeler, the shape and structure of the power unit, the size and structure of the motor, the shape and arrangement of the idle gear, the support structure of the idle gear, the shape and structure of the first cover and the second cover, the structure of the transmission mechanism and the clutch mechanism, etc. are not limited to the above embodiments, and various modifications are possible. For example, in the specification, the clutch mechanism may be disposed above the motor. Thereby, since the heavy motor is positioned below, the center of gravity of the power unit can be lowered. The power unit according to the present invention is not limited to motorcycles, and can be applied to various vehicles such as three-wheelers and four-wheelers.

[0045] 1... electric two-wheeler, 17... drive sprocket (output member), 24... first cover, 25... second cover, 50... output gear of the motor, 52... flywheel, 60... idle gear, 60a... rotation axis of the idle gear, 61... bearing portion of the idle gear, 62... bearing holding member, 63... through hole, 81... output shaft of the transmission mechanism, P... power unit, M... motor (power source), JM... rotation axis of the power source, CL... clutch mechanism, TM... transmission mechanism

Claims

1. A power unit (P) having a power source (M), a clutch mechanism (CL) for adjusting the capacity of rotational power transmitted from the power source (M) to a transmission mechanism (TM), and an output member (17) supported on the output shaft (81) of the transmission mechanism (TM), wherein the output member (17) is positioned on one side in the width direction of the power unit (P) at a position that does not overlap with the rotation shaft (JM) of the power source (M) in an axial view, and the clutch mechanism (CL) is positioned on the other side in the width direction, and an idler gear (60) is disposed between the power source (M) and the clutch mechanism (CL) in the width direction of the power unit (P) for transmitting the rotational power to the clutch mechanism (CL).

2. The power unit according to claim 1, characterized in that the clutch mechanism (CL) is located below the power source (M).

3. The power unit according to claim 1, characterized in that a flywheel (52) is attached to the rotating shaft (JM) of the power source (M), the idler gear (60) is disposed between the flywheel (52) and the clutch mechanism (CL) in the axial direction of the rotating shaft (JM), and the bearing portion (61) of the flywheel (52) and the idler gear (60) overlap in an axial view.

4. The power unit according to claim 3, characterized in that the idler gear (60) is cantilevered and its gear portion is positioned closer to the flywheel (52).

5. The power unit according to claim 1 or 2, characterized in that, in an axial view, at least a portion of the idler gear (60) overlaps with the clutch mechanism (CL).

6. The power unit according to claim 3, characterized in that the idler gear (60) is provided with at least one through hole (63), and at least a portion of the bearing retaining member (62) that fixes the bearing portion (61) overlaps with the through hole (63) when viewed in the axial direction of the idler gear (60).

7. The power unit according to claim 1 or 2, comprising a first cover (24) covering the idler gear (60) and a second cover (25) which is configured separately from the first cover (24) and covers the clutch mechanism (CL), wherein the rotating shaft (60a) of the idler gear (60) is pivotally supported by the first cover (24).

8. The power unit according to claim 1 or 2, characterized in that the output member (17) and the clutch mechanism (CL) overlap in an axial view of the output shaft (81).

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