JP7474139B2 - Electronic Gear Transmission - Google Patents

Description

The present invention relates to a gear transmission that uses the power of an electric motor to change gears.

In a gear transmission used in a vehicle such as a motorcycle, the driver operates an operating lever to rotate a shift drum, which displaces a shift fork guided by the shift drum, thereby changing gears.

Patent No. 4712952

However, with the increasing sophistication of vehicles in recent years, it is becoming conceivable to electrify the transmission. In this case, in order to ensure the accuracy of the gear shifting operation in an electric transmission, it is necessary to prevent a discrepancy between the driver's gear shifting intention and the gear shifting operation of the electric motor.

Therefore, the present invention aims to provide an electric gear transmission that accurately reflects the driver's intentions.

The electric gear transmission according to one aspect of the present invention includes an electric motor, a shift fork that displaces for gear changing, a shift drum having a guide groove that guides the shift fork, and a speed change power transmission mechanism having an intermittent rotation mechanism that intermittently rotates the shift drum at a predetermined angle by the power of the electric motor. The intermittent rotation mechanism includes a change shaft to which the power of the electric motor is input, a change lever unit including a change lever that extends in the radial direction of the change shaft and is connected to the change shaft, a return spring that biases the change lever so that the phase angle of the change lever is maintained at a predetermined lever reference angle, and a change cam that rotates integrally with the shift drum around the rotation axis of the shift drum. The speed change power transmission mechanism is configured to displace the shift fork when the intermittent rotation mechanism performs a predetermined operation sequence from a state in which the phase angle of the change lever is the lever reference angle. The operation sequence is performed when the electric motor performs a predetermined rotation operation including both clockwise and counterclockwise rotation.

According to the above configuration, when an abnormality occurs in which the electric motor continues to rotate in only one direction, the intermittent rotation mechanism cannot complete the specified operating sequence, and no gear shifting occurs. In other words, the electric motor is prevented from operating and causing a gear shift when the driver does not intend to change gear.

The present invention provides an electric gear transmission that accurately reflects the driver's intentions.

FIG. 1 is a schematic diagram of a vehicle equipped with an electric gear transmission according to a first embodiment. FIG. 2 is a perspective view of the speed-changing power transmission mechanism shown in FIG. 1 as viewed from the right rear. 3 is a perspective view of the change lever and the like of the intermittent rotation mechanism shown in FIG. 2, as viewed from the left. 4A and 4B are diagrams showing the operation of the selector shown in FIG. 5A to 5D are diagrams showing the operation of the change cam and the shift pawl shown in FIG. FIG. 6 is a side view of the intermittent rotation mechanism of the electric gear transmission according to the second embodiment, as viewed from the right. 7A to 7D are diagrams illustrating the operation of the change cam and the shift pawl shown in FIG. FIG. 8 is a development view of a shift drum according to the third embodiment.

The following describes the embodiment with reference to the drawings.

[First embodiment]
FIG. 1 is a schematic diagram of a vehicle 1 equipped with an electric gear transmission 4 according to a first embodiment. Although FIG. 1 illustrates a saddle-ride vehicle (e.g., a motorcycle), other types of vehicles may be used. As shown in FIG. 1, the vehicle 1 includes an engine E (driving source) that is an internal combustion engine. A crankshaft Ea of the engine E is connected to the electric gear transmission 4 via a reduction gear 2 (primary gear) and a main clutch 3 (e.g., a friction clutch). The electric gear transmission 4 is connected to a driving wheel 6 via an output transmission mechanism 5 (e.g., a chain sprocket mechanism, a belt pulley mechanism, a drive shaft gear mechanism, etc.).

The electric gear transmission 4 includes an electric motor M, an input shaft 11, an output shaft 12, and multiple sets of speed-change gear pairs 13 that change the rotation speed of the driving force transmitted from the input shaft 11 to the output shaft 12. The multiple sets of speed-change gear pairs 13 have different reduction ratios. The speed-change gear pairs 13 include dog gears 13a that select a gear stage by sliding displacement. In the electric gear transmission 4, one of the speed-change gear pairs 13 is selected by the dog gears 13a to perform a gear change. The driving force from the crankshaft Ea of the engine E is transmitted to the input shaft 11 via the reduction gears 2 and 3. The driving force output from the output shaft 12 is transmitted to the drive wheels 6 via the power output mechanism 5.

A shift fork 15 that displaces to change gears is slidably supported on a support shaft 14 that is provided parallel to the input shaft 11 and the output shaft 12. The tip of the shift fork 15 is connected to a dog gear 13a. The electric gear transmission 4 is equipped with a shift power transmission mechanism 16 that converts the rotational power (shift power) of the electric motor M into power that slides and displaces the shift fork 15. The shift power transmission mechanism 16 has a shift drum 21 and an intermittent rotation mechanism 22. The intermittent rotation mechanism 22 is operated by the rotational power of the electric motor M and intermittently rotates the shift drum 21 at a predetermined angle θ.

The base end of the shift fork 15 fits into the guide groove 21a of the shift drum 21. When the shift drum 15 rotates, the shift fork 15 guided by the guide groove 21a slides the corresponding dog gear 13a along the input shaft 11 or the output shaft 12. As a result, one of the multiple sets of speed-change gear pairs 13 with the desired reduction ratio is in a power transmission state, and the power transmission path of the desired gear stage is selected in the electric gear transmission 4.

Figure 2 is a perspective view of the gear shift power transmission mechanism 16 shown in Figure 1, seen from the right rear. Figure 3 is a perspective view of the change lever 41 and other parts of the intermittent rotation mechanism 22 shown in Figure 2, seen from the left. Note that the selector 42 is omitted from Figure 3. As shown in Figures 2 and 3, the gear shift power transmission mechanism 16 has a shift drum 21 and an intermittent rotation mechanism 22, and displaces the shift fork 15 by the rotational power of the electric motor M. The intermittent rotation mechanism 22 has a change shaft 31, a change lever unit 32, a return spring 33, a change cam 34, a stopper rod 35 (disengagement member), and a cam positioning mechanism 36.

The axis X of the change shaft 31 is arranged parallel to the axis Y of the shift drum 21. An electric motor M is attached to a first end of the change shaft 31, and a change lever unit 32 and the like are attached to a second end of the change shaft 31. The power of the electric motor M is input to the change shaft 31, and the change shaft 31 rotates around its axis X. The intermittent rotation mechanism 22 performs a predetermined operation sequence when the electric motor M controlled by the controller 7 performs a predetermined rotation operation including both clockwise and counterclockwise rotation. The controller 7 has a processor, storage (e.g., hard disk, flash memory, etc.), main memory (RAM), an I/O interface, etc., and executes a program that controls the electric motor M in response to a predetermined gear shift command.

The change lever unit 32 has a change lever 41 and a selector 42. The change lever 41 extends in the radial direction of the change shaft 31 and is connected to the change shaft 31. The change shaft 31 is inserted through the change lever 41 so as to be rotatable relative to the change shaft 31. The change lever 41 includes a lever body 51, a slider 52, a rivet 53, and a slider spring 54. The lever body 51 and the slider 52 are plate-shaped.

The lever body 51 is supported on the change shaft 31 so as to be rotatable relative to the change shaft 31. The lever body 51 has a base 61 that fits onto the change shaft 31, and a slider support portion 62 that protrudes from the lever body 51 in a radial direction perpendicular to the axis X. The base 61 has a biased portion 61a, a stopper hole 61b, and a pair of engaged portions 61c.

The biased portion 61a comes into contact with the return spring 33 and receives a biasing force from the return spring 33. The stopper hole 61b has an oval shape extending in the circumferential direction around the axis X. The pair of engaged portions 61c are configured to be engageable with the engaging portions 69 described below. The engaged portions 61c are, for example, holes or recesses. The slider support portion 62 has a pin hole 62a through which the rivet 53 passes. Note that one of the pair of engaged portions 61c is for shifting up, and the other of the pair of engaged portions 61c is for shifting down.

The slider 52 is slidably stacked on the slider support portion 62. The slider 52 has a guide hole 65 through which the shaft of the rivet 53 is inserted. The guide hole 65 extends in the radial direction so that the shaft of the rivet 53 can be guided in the radial direction. The rivet 53 passes through the guide hole 65 of the slider 52 and is fastened to the pin hole 62a of the lever body 51. Note that the object inserted into the guide hole 65 of the slider 52 is not limited to a rivet, and other objects (e.g., pins and retainers) that function as guide pins may be used.

The slider 52 has a pair of shift pawls 66 at its longitudinal tip side (the radially outer side). The pair of shift pawls 66 are formed by bending the tip of the slider 52 toward the change cam 34. The pair of shift pawls 66 are spaced apart from each other in the radial direction and in a direction perpendicular to the axis X. When viewed from the axis X direction, the pair of shift pawls 66 have a symmetrical shape with respect to an imaginary line V extending in the radial direction and passing through the midpoint between the pair of shift pawls 66.

The shift pawl 66 has a tapered shape. The shift pawl 66 has a shift surface 66a adjacent to one side of the tip of the shift pawl 66 and a clearance surface 66b adjacent to the other side of the tip of the shift pawl 66. The shift surfaces 66a of the pair of shift pawls 66 face each other. The shift surfaces 66a are substantially parallel to the imaginary line V. The clearance surface 66b is disposed farther from the imaginary line V than the shift surfaces 66a. The clearance surface 66b forms a larger angle with respect to the imaginary line V than the shift surfaces 66a. The clearance surface 66b is inclined so as to move away from the axis X as it moves away from the tip of the shift pawl 66.

The slider spring 54 biases the slider 52 in a direction in which the slider 52 approaches the axis X. One end of the slider spring 54 is attached to the slider 52, and the other end of the slider spring 54 is attached to a ring that is fitted onto the change shaft 31 so as to be relatively rotatable. When the slider 52 slides radially outward relative to the lever body 51, the slider spring 54 applies a biasing force that tends to return the slider 52 radially inward.

The return spring 33 is a torsion spring fitted onto the change shaft 31. One end and the other end of the return spring 33 sandwich the biased portion 61a of the lever body 51 in the circumferential direction around the axis X. A stopper rod 35 passes between one end and the other end of the return spring 33. The return spring 33 biases the change lever 41 so that the phase angle of the change lever 41 around the axis X is maintained at a predetermined lever reference angle.

The change cam 34 rotates integrally with the shift drum 21 around the rotation axis of the shift drum 21. The change cam 34 is fixed to the axial end face of the shift drum 21 and faces the change lever 41. The change cam 34 has a disk portion 44 and multiple passive protrusions 45. The disk portion 44 is arranged so as to be perpendicular to the axis Y of the shift drum 21. A plurality of positioning recesses 44a are formed at equal intervals in the circumferential direction on the outer periphery of the disk portion 44. The number of recesses 44a is the same as the number of gear stages of the electric gear transmission 4. In other words, the outer periphery of the disk portion 44 has repeated unevenness formed thereon, and the unevenness has a smooth curved shape.

The multiple passive protrusions 45 protrude from the surface of the disk portion 44 that faces the shift lever 41. The multiple passive protrusions 45 are arranged at equal intervals in the circumferential direction around the axis Y. The number of the multiple passive protrusions 45 is the same as the number of gears of the electric gear transmission 4. The position of the passive protrusions 45 in the Y direction overlaps with the position of the shift pawl 66 in the Y direction.

The stopper rod 35 is inserted into the stopper hole 61b of the lever body 51 with some play in the rotational direction of the change lever 41. The stopper rod 35 is fixed to the side wall of the transmission case 10 (see Figure 4) and protrudes outward from the side wall (towards the lever body 51). The tip of the stopper rod 35 is hemispherical.

The cam positioning mechanism 36 has a positioning arm 47, a positioning roller 48, and a positioning spring 49. The base end of the positioning arm 47 is rotatably supported on the side wall of the transmission case 10. The positioning roller 48 is rotatably attached to the tip end of the positioning arm 47. The positioning roller 48 faces the outer periphery of the change cam 34. The positioning spring 49 biases the positioning arm 47 in a direction in which the positioning roller 48 presses the outer periphery of the change cam 34. The biasing force of the positioning arm 47 causes the positioning roller 48 to fit into the recess 44a on the outer periphery of the change cam 34, and the phase angle around the axis Y of the change cam 34 is positioned according to the gear shift stage.

The selector 42 selectively transmits the rotation of the change shaft 31 to the change lever 41. The selector 42 includes an engagement member 56 and a selection mechanism 57. The engagement member 56 is fitted onto the change shaft 31 so as to be unable to rotate relative to the change shaft 31 and to be movable relative to the change shaft 31 in the direction of the axis X. The engagement member 56 has a swinging portion 68 extending radially from the change shaft 31, and an engagement portion 69 that faces the base 61 of the lever body 51 from the swinging portion 68.

The oscillating portion 68 extends from the change shaft 31 in a direction approaching the stopper hole 61b and a direction approaching the engaged portion 61c. In this embodiment, the stopper hole 61b and the engaged portion 61c are located on opposite sides of the change shaft 31, but they may be located on the same side of the change shaft 31. In that case, the oscillating portion 68 may be shaped to extend in only one direction from the change shaft 31.

The oscillating part 68 has a pressure receiving part 68a in the area facing the stopper hole 61b. When the phase angle of the change shaft 31 is a predetermined shaft reference angle, the pressure receiving part 68a is pressed against the tip of the stopper rod 35. When viewed from the extension direction of the oscillating part 68, the pressure receiving part 68a has a U-shape or V-shape that is convex toward the stopper rod 35.

The engaging portion 69 has a shape that allows it to engage with the engaged portion 61c. The direction of the engaging operation of the engaging portion 69 with respect to the engaged portion 61c is parallel to the axis X direction. The engaging portion 69 has, for example, a convex shape. The shapes of the engaging portion 69 and the engaged portion 61c may be reversed. When the phase angle of the change lever 41 is the lever reference angle and the phase angle of the change shaft 31 is the shaft reference angle (standby state), the engaging portion 69 faces the surface of the base 61 of the lever body 51 between the pair of engaged portions 61c.

The selection mechanism 57 has an engagement spring 71 and an engagement release member (stopper rod 35). A spring seat 31a is provided on the change shaft 31 on the opposite side of the lever body 51 with respect to the engagement member 56 so that it cannot be displaced in the direction of the axis X. The engagement spring 71 is interposed between the engagement member 56 and the spring seat 31a. When the lever body 51 and the change shaft 31 are in the standby state, the engagement portion 69 is slidably abutted against the surface of the base portion 61 of the lever body 51 by the biasing force of the engagement spring 71. When the lever body 51 and the change shaft 31 are in the standby state, the stopper rod 35 as an engagement release member presses the pressure receiving portion 68a so that the engagement member 56 moves away from the lever body 51 in the direction of the axis X.

4(A) and (B) are operation diagrams of the selector 42 shown in FIG. 2. As shown in FIGS. 2 and 4(A), when the lever body 51 and the change shaft 31 are in the standby state, the pressure receiving portion 68a is pressed against the stopper rod 35 and the engagement portion 69 is pressed against the base portion 61 of the lever body 51, and the engagement member 56 moves away from the lever body 51 against the engagement spring 71. As shown in FIG. 4(B), when the change shaft 31 driven by the electric motor M rotates in the first direction (e.g., clockwise) and the engagement member 56 rotates around the axis X, the pressure receiving portion 68a no longer faces the stopper rod 35 in the axis X direction. Then, when the engagement portion 69 of the engagement member 56 faces the engaged portion 61c of the lever body 51 in the axis X direction, the engagement member 56 is displaced in the axis X direction to approach the lever body 51 by the engagement spring 71 that biases the engagement member 56 in the engagement operation direction, and the engagement portion 69 engages with the engaged portion 61c.

When the change shaft 31 rotates from this engaged state in a second direction (e.g., counterclockwise) opposite to the first direction, the change lever 41 rotates together with the engaging member 56, causing the shift drum 21, described below, to rotate. When the shift drum 21 achieves the angular displacement θ at which it shifts to the adjacent gear, the longitudinal edge of the stopper hole 61b of the lever body 51 may interfere with the stopper rod 35. When the shift drum 21 completes the shift to the adjacent gear, the electric motor M rotates in the reverse direction, causing the change shaft 31 to rotate in the first direction, so that the pressure receiving portion 68a faces the stopper rod 35, as shown in FIG. 4(A).

As a result, the stopper rod 35 presses the pressure receiving portion 68a of the engaging member 56 in the disengaging direction opposite to the engaging direction, and the engaging member 56 moves away from the lever body 51 against the engaging spring 71, disengaging the engaging portion 69 from the engaged portion 61c. In other words, the stopper rod 35 also serves as a disengaging member that disengages the engaging portion 69 of the engaging member 56 from the engaged portion 61c of the lever body 51.

Figures 5 (A) to (D) are operation diagrams of the change cam 34 and the shift pawl 66 shown in Figure 2. The following describes the gear shifting operation in the order of Figures 5 (A) to (D) with reference to Figure 2 and other figures. When the change lever 41 and the change shaft 31 are in the standby state, the pair of shift pawls 66 are positioned to sandwich the two adjacent passive protrusions 45 of the change cam 34 (see Figure 5 (A)). That is, the gear shift surface 66a of the shift pawl 66 faces the passive protrusions 45 in the circumferential direction around the Y axis. In this state (at the start of the first operation described below), the pressure receiving portion 68a of the engaging member 56 is pressed by the tip of the stopper rod 35 in the release operation direction, and the engaging portion 69 abuts against the surface around the engaged portion 61c of the lever body 51.

From this state, the controller 7, which has received a predetermined shift command, controls the electric motor M to rotate the electric motor M in the first direction. Then, the change shaft 31 rotates in the first direction, and the intermittent rotation mechanism 22 transitions from the state shown in FIG. 4(A) to the state shown in FIG. 4(B) (first operation). That is, during the first operation, the engaging portion 69 is not engaged with the engaged portion 61c, so the engaging member 56 rotates around the axis X, while the change lever 41 does not rotate around the axis X and remains stationary. Therefore, during the first operation, the shift pawl 66 remains stationary in the state shown in FIG. 5(A) and does not rotate the change cam 34. At the end of the first operation, the engaging portion 69 faces the engaged portion 61c in the direction of the engaging operation, and the engaging portion 69 engages with the engaged portion 61c due to the biasing force of the engaging spring 71.

When the first operation is completed, the electric motor M rotates in the second direction, causing the change shaft 31 to rotate in the second direction (second operation). During the second operation, the engaging portion 69 is engaged with the engaged portion 61c, so that the engaging member 56 and the change lever 41 rotate integrally in the second direction around the axis X, and one of the shift surfaces 66a of the pair of shift pawls 66 presses the passive convex portion 45 of the change cam 34 around the axis Y, causing the change cam 34 to rotate by the predetermined angle θ around the axis Y (see FIG. 5B).

Then, the positioning roller 48 of the cam positioning mechanism 36 fits into the recess 44a on the outer periphery of the disk portion 44 of the change cam 34 by the biasing force of the positioning spring 49, and the change cam 34 is positioned. As a result, the shift fork 15 guided by the guide groove 21a of the shift drum 21 slides and displaces the dog gear 13a, realizing a shift from the current gear to the adjacent gear. The first and second operations constitute the operation sequence of the intermittent rotation mechanism 22.

As the second operation approaches completion, the pressure receiving portion 68a of the engaging member 56 is gradually pressed against the tip of the stopper rod 35, and the engaging member 56 gradually moves away from the lever body 51 in the disengagement direction. When the second operation ends, the pressure receiving portion 68a of the engaging member 56 is pressed against the apex of the stopper rod 35, and the engagement between the engaging portion 69 and the engaged portion 61c is released. When the engaging portion 69 is disengaged from the engaged portion 61c, the return spring 33 rotates the shift lever 41 in the first direction. At this time, one of the relief surfaces 66b of the pair of shift pawls 66 slides against the passive convex portion 45 of the change cam 34, and the shift pawl 66 escapes radially outward due to the reaction force from the passive convex portion 45, and the slider 52 slides radially outward relative to the lever body 51 (see FIG. 5(C)).

When the shift pawl 66, which has been sliding against the passive convex portion 45 at the clearance surface 66b, overcomes the passive convex portion 45 of the change cam 34 due to the rotation of the change lever 41, the slider 52 slides radially inward relative to the lever body 51 due to the biasing force of the slider spring 54, and the phase angle of the change lever 41 returns to the lever reference angle (see FIG. 5(D)). After the second operation is completed, the electric motor M rotates in the first direction to rotate the change shaft 31 in the first direction, and the phase angle of the change shaft 31 is also returned to the shaft reference angle.

According to the configuration described above, when an abnormality occurs in which the electric motor M continues to rotate in only one direction, the intermittent rotation mechanism 22 cannot complete the operation sequence, and no gear shifting occurs. In other words, the electric motor M is prevented from operating and shifting gears when the driver does not intend to shift gears. Thus, it is possible to provide an electric gear transmission 4 that accurately reflects the driver's intentions.

In addition, the change lever unit 32 is configured so that the change cam 34 does not rotate during the first operation, and rotates the change cam 34 by the predetermined angle θ during the second operation, so that the electric gear transmission 4 can be realized by making the most of the existing configuration of the manual gear transmission.

In addition, when the change shaft 31 rotates in only one direction, the selector 42 performs only the first operation and not the second operation, so the change cam 34 does not rotate. This makes it possible to simply realize a configuration in which no gear change occurs when the electric motor M continues to rotate in only one direction.

In addition, due to the engagement spring 71 and the stopper rod 35 (disengagement member), during the first operation, the engagement portion 69 does not engage with the engaged portion 61c, and the selector 42 does not transmit the rotation of the change shaft 31 to the change lever 41. Then, since the engagement portion 69 engages with the engaged portion 61c at the end of the first operation, during the second operation, the engagement portion 69 engages with the engaged portion 61c, and the selector 42 transmits the rotation of the change shaft 31 to the change lever 41. Therefore, the selector 42 can be realized with a simple mechanical structure. Furthermore, since the stopper rod 35 also serves as the disengagement member, the number of parts can be reduced and the size can be made smaller.

[Second embodiment]
Fig. 6 is a side view of the intermittent rotation mechanism 122 of the electric gear transmission 104 according to the second embodiment, as seen from the right. Note that the same reference numerals are used to designate configurations common to the first embodiment, and descriptions thereof will be omitted. As shown in Fig. 6, in the intermittent rotation mechanism 122 of the second embodiment, a change lever unit 132 does not include the selector 42 shown in the first embodiment, but includes a change lever 141, and the shape of a shift pawl 166 of the change lever unit 132 is different from the shape of the shift pawl 66 shown in the first embodiment.

The change lever 141 comprises a lever body 151, a slider 152, a rivet 53, and a slider spring 54. The lever body 151 is connected to the change shaft 31 so as to be non-rotatable relative to it and non-displaceable relative to it in the radial direction. The slider 152 is supported by the lever body 151 so as to be slidable in the radial direction. Since there is no selector 42 in the second embodiment, there is no engaged portion 61c shown in the first embodiment on the base 161 of the lever body 151. The slider 152 has a pair of shift pawls 166 (see FIG. 7) facing the change cam 34 at its tip end in the longitudinal direction (the radially outer side).

Figures 7 (A) to (D) are operation diagrams of the change cam 34 and the shift pawl 166 shown in Figure 6. As shown in Figure 7 (A), the shift pawl 166 of the slider 152 has a shift surface 166a adjacent to one side of the tip of the shift pawl 166 and a clearance surface 166b adjacent to the other side of the tip of the shift pawl 166. The clearance surfaces 166b of the pair of shift pawls 166 face each other. The shift surfaces 166a of the pair of shift pawls 166 face opposite each other. In other words, the positional relationship between the shift surface 166a and the clearance surface 166b is opposite to that of the first embodiment. The clearance surfaces 166b of the pair of shift pawls 166 are inclined so as to move away from the axis X as they move away from the tip of the shift pawl 166. The shift surfaces 166a of the pair of shift pawls 166 are substantially parallel to each other.

The gear shifting operation will be described below in the order of Fig. 7 (A) to (D) with reference to Fig. 6. When the change lever 141 and the change shaft 31 are in the standby state, the pair of shift pawls 166 are positioned to sandwich the passive convex portion 45 of the change cam 34 in the circumferential direction around the Y axis (see Fig. 7 (A)). From this state, the controller 7 (see Fig. 1) receives a predetermined gear shift command and controls the electric motor M to rotate in the first direction. Then, the change lever 141 rotates in the first direction together with the change shaft 31, and one of the relief surfaces 166b of the pair of shift pawls 166 slides against the passive convex portion 45 of the change cam 34 (first operation).

At this time, the shift pawl 166 escapes radially outward due to the reaction force from the passive convex portion 45, and the slider 152 slides radially outward relative to the lever body 151 (see FIG. 5B). That is, during the first operation, the change cam 34 does not rotate. Then, when the shift pawl 166, which has been sliding against the passive convex portion 45 at the escape surface 166b, overcomes the passive convex portion 45 of the change cam 34 due to the rotation of the change lever 141, the slider 152 slides radially inward relative to the lever body 151 due to the biasing force of the slider spring 54. Then, the shift surface 166a of the shift pawl 166 faces the passive convex portion 45, and the first operation ends (see FIG. 5C).

When the first operation is completed, the electric motor M rotates in a second direction opposite to the first direction, and the change shaft 31 rotates in the second direction so that the phase angle of the change shaft 31 returns to the shaft reference angle (second operation). Then, the change lever 141 rotates in the second direction around the axis X, and the shift surface 166a of the shift pawl 166 presses the passive convex portion 45 of the change cam 34 around the axis Y, causing the change cam 34 to rotate by the predetermined angle θ around the axis Y (see FIG. 5(D)).

As a result, the shift fork 15 guided by the guide groove 21a of the shift drum 21 (see FIG. 1) slides and displaces the dog gear 13a, realizing a shift from the current gear to the adjacent gear. The first and second operations constitute the operation sequence of the intermittent rotation mechanism 122. After the second operation is completed, power supply to the electric motor M is stopped, and the phase angle of the change lever 141 and the change shaft 31 is maintained at the reference angle.

According to the above configuration, when the change shaft 31 rotates in only one direction, only the first operation is performed and not the second operation, so the change cam 34 does not rotate. Therefore, a configuration in which no gear shifting occurs when the electric motor M continues to rotate in only one direction can be simply realized. Note that the other configurations are the same as those of the first embodiment described above, so a description thereof will be omitted.

[Third embodiment]
FIG. 8 is a development view of the shift drum 221 according to the third embodiment. As shown in FIG. 8, the shift drum 221 has a larger diameter than the shift drum 21 of the first embodiment. The guide groove 221a formed on the outer peripheral surface of the shift drum 221 is longer than the guide groove 21a of the first embodiment. In the third embodiment, the change lever unit 132 (without the selector 42) of the second embodiment is used (however, the shift claw 66 of the first embodiment is used as the shift claw), and the other configurations of the intermittent rotation mechanism are the same as those of the first embodiment. In addition, the intermittent rotation mechanism of the third embodiment may be the same as the configuration of the aforementioned Japanese Patent No. 4712952.

The guide groove 221a of the shift drum 221 has multiple gear regions corresponding to the multiple gears. In this embodiment, the multiple gear regions of the guide groove 221a have first to sixth gear regions (#1 to #6). The intermittent rotation mechanism of the third embodiment is operated by the rotational power of the electric motor M (see FIG. 1) and rotates the shift drum 221 intermittently every predetermined angle θ.

At least one of the multiple gear ranges (#1 to #6) has a length such that the gear range does not change even when the shift drum 221 rotates through the specified angle θ in the downshift direction, and the gear range is changed to the next lower gear range when the shift drum 221 rotates through 2θ, which is twice the specified angle θ. In this embodiment, the second to sixth gear ranges (#2 to #6) of the guide groove 221a have a length such that the gear range does not change even when the shift drum 221 rotates through the specified angle θ in the downshift direction, and the gear range is changed to the next lower gear range when the shift drum 221 rotates through 2θ, which is twice the specified angle θ.

When the electric motor M is driven under the control of the controller 7 (see FIG. 1) and the intermittent rotation mechanism performs a predetermined operation sequence, the shift fork 15 is displaced and a gear change is performed. The operation sequence includes a first operation in which the change shaft 31 (see FIG. 1) rotates in a first direction, a second operation in which the change shaft 31 rotates in a second direction opposite to the first direction after the first operation, and a third operation in which the change shaft 31 rotates in the first direction after the second operation.

When the gear stage is 2nd to 6th gear, and the phase angle of the change lever is the lever reference angle and the phase angle of the change shaft is the shaft reference angle (standby state), the shift fork 15 is positioned at the positions indicated by "#2* to #6*" in FIG. 8. For example, if the gear stage is currently 6th gear, the first action moves the shift fork 15 from the "#6*" position to the "#6" position. In other words, the first action does not result in a change in gear stage, and 6th gear is maintained.

Next, in the second action, the change lever and the change shaft simply return to the standby state, so there is also no change in gear. Next, the third action moves the shift fork 15 from the "#6" position to the "#5*" position. That is, the third action causes a change in gear. That is, when shifting down from the current gear (2nd to 6th gear) to the adjacent gear, the guide groove 221a displaces the shift fork 15 by performing all of the first to third actions.

The above configuration allows a simple configuration in which no gear change occurs when the electric motor M continues to rotate in only one direction to be realized by lengthening the guide groove 221a of the shift drum 221. Furthermore, when upshifting from first to fifth gear, the gear stage is changed when the shift drum 221 rotates the predetermined angle θ (for example, the shift fork position moves from "#5*" to "#6"), so upshifting can be performed more quickly than downshifting. Note that the other configurations are the same as those of the first embodiment described above, so a description thereof will be omitted.

The present invention is not limited to the above-described embodiments, and the configurations can be changed, added, or deleted. For example, a portion of the configuration in one embodiment can be separated from the other configurations in that embodiment and arbitrarily extracted, and a portion of the configuration in one embodiment may be applied to another embodiment.

Reference Signs List 4 Electric gear transmission 10 Transmission case 15 Shift fork 16 Speed change power transmission mechanism 21, 221 Shift drum 21a, 221a Guide groove 22 Intermittent rotation mechanism 31 Change shaft 32 Change lever unit 33 Return spring 34 Change cam 35 Stopper rod (disengagement member)
Reference Signs List 41 Change lever 42 Selector 45 Passive convex portion 51 Lever body 52 Slider 54 Slider spring 56 Engagement member 57 Selection mechanism 61c Engaged portion 61b Stopper hole 66, 166 Shift pawl 66b, 166b Relief surface 66a, 166a Shift surface 68a Pressure receiving portion 69 Engagement portion 71 Engagement spring M Electric motor

Claims (7)

An electric motor;
A shift fork that displaces for gear changes;
a shift drum having a guide groove for guiding the shift fork; and an intermittent rotation mechanism for intermittently rotating the shift drum at predetermined angles by power of the electric motor;
The intermittent rotation mechanism includes:
a change shaft to which the power of the electric motor is input;
a change lever unit including a change lever extending in a radial direction of the change shaft and connected to the change shaft;
a return spring that biases the change lever so that the phase angle of the change lever is maintained at a predetermined reference angle;
A change cam that rotates integrally with the shift drum around the rotation axis of the shift drum,
the speed change power transmission mechanism is configured to displace the shift fork when the intermittent rotation mechanism performs a predetermined operation sequence from a state in which the phase angle of the change lever is the reference angle,
An electric gear transmission, wherein the operating sequence is performed when the electric motor performs a predetermined rotational operation including both clockwise and counterclockwise rotation. The operation sequence includes a first operation in which the change shaft rotates in one direction, and a second operation in which the change shaft rotates in the other direction after the first operation,
2. The electric gear transmission according to claim 1, wherein the change lever unit is configured not to rotate the change cam during the first operation, and to rotate the change cam by the predetermined angle during the second operation. The change lever is provided to be rotatable relative to the change shaft,
The change lever unit further includes a selector that selectively transmits rotation of the change shaft to the change lever,
The change lever includes an engaged portion,
The selector:
an engaging member including an engaging portion and provided on the change shaft so as not to rotate relative to the change shaft;
3. The electric gear transmission according to claim 2, further comprising a selection mechanism that operates the engaging member so that the engaging portion is disengaged from the engaged portion when the first operation is performed, and operates the engaging member so that the engaging portion is engaged with the engaged portion when the second operation is performed. the engaging member is provided so as to be displaceable relative to the change shaft in an axial direction along which the axis of the change shaft extends ,
a direction of engagement of the engaging portion with the engaged portion is parallel to the axial direction;
The selection mechanism includes:
an engagement spring that biases the engagement member in the engagement operation direction;
a disengagement member that presses the engagement member in a disengagement operation direction opposite to the engagement operation direction when the phase angle is the reference angle,
4. The electric gear transmission according to claim 3, wherein the engaging portion abuts against a peripheral surface of the engaged portion of the shift lever at the start of the first operation, and is positioned so as to face the engaged portion in the direction of the engaging operation at the end of the first operation. The intermittent rotation mechanism includes:
A stopper rod fixed to the transmission case;
a stopper hole formed in the change lever, through which the stopper rod is inserted with play in a rotational direction of the change lever;
the engaging member has a pressure receiving portion that is pressed in the release operation direction by the stopper rod at the start of the first operation,
5. The electric gear transmission according to claim 4, wherein the stopper rod also serves as the disengagement member. The change cam includes passive convex portions that are equally spaced in a circumferential direction around the rotation axis,
The change lever is
a lever body connected to the change shaft so as not to rotate relative thereto and so as not to move relative thereto in the radial direction;
a slider that includes a shift pawl that presses the passive convex portion in the circumferential direction to rotate the change cam and is supported by the lever body so as to be slidable in the radial direction;
a slider spring that biases the slider inward in the radial direction relative to the lever body,
The shift claw is
a relief surface that receives a reaction force from the passive convex portion during the first action and displaces the slider outward in the radial direction against the slider spring;
3. The electric gear transmission according to claim 2, further comprising: a shift surface that presses against the passive convex portion during the second action to rotate the change cam. the operation sequence includes a first operation in which the change shaft rotates in one direction, a second operation in which the change shaft rotates in the other direction after the first operation, and a third operation in which the change shaft rotates in the one direction after the second operation,
2. The electric gear transmission according to claim 1, wherein the guide groove is configured to displace the shift fork by performing the first to third actions when changing gears from a current gear to an adjacent gear.

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