JP7422938B2 - transmission - Google Patents

Description

The present invention relates to a transmission, and more particularly to a transmission that transmits power from a motor.

The prior art disclosed in Patent Document 1 as a transmission that transmits the power of a motor has an input shaft and an output shaft arranged on the same axis, and odd-numbered gears and even-numbered gears that transmit the rotation of the input shaft to the output shaft. The vehicle is equipped with two power transmission systems, and a clutch arranged between the two power transmission systems to switch the power transmission systems. By alternating between odd-numbered gears and even-numbered gears when shifting up from a low gear to a high gear, it is possible to realize a so-called seamless shift, which reduces the decrease in torque of the output shaft during a gear shifting operation.

Patent No. 6588051

Since the moment of inertia of the vehicle is large, the rotational speed of the driven side hardly changes during a gear shifting operation, but the rotational speed of the driving side changes within a short period of time. The prior art has a problem in that an excessive torque peak occurs due to a sudden change in kinetic energy on the drive side, resulting in impact and abnormal noise. Further, in the prior art, since the input shaft and the output shaft are arranged coaxially, there is a problem that the transmission becomes long in the axial direction.

The present invention has been made to solve this problem, and aims to provide a transmission that can reduce the torque drop and impact on the output shaft during gear shifting operations, and further reduce the axial dimension. do.

To achieve this objective, the transmission of the present invention has an input shaft to which the rotation of the motor is input, an output shaft disposed on a different axis from the input shaft, and an output shaft disposed on different axes parallel to the output shaft. A plurality of power transmission systems that transmit the rotation of the input shaft to the output shaft at mutually different gear ratios through a plurality of intermediate shafts that are connected to each other and constantly meshing gears that are linked between each of the plurality of intermediate shafts and the output shaft. a synchronization mechanism that reduces the difference between the rotational speed on the driving side and the rotational speed on the driven side by frictional force, and the plurality of power transmission paths include a first path and a second path for adjacent gears. The synchronizing mechanism is disposed on the first path and operates the synchronizing mechanism to switch between a state in which the first path transmits torque and a state in which the second path transmits torque.

According to the first aspect, the rotation of the input shaft is transmitted to the output shaft, which is disposed on a different axis from the input shaft to which the rotation of the motor is inputted, through a plurality of power transmission paths at mutually different gear ratios. . Since the input shaft and the output shaft are arranged on different axes, the axial dimension of the transmission can be reduced.

The plurality of power transmission paths include a first path and a second path for adjacent gear stages, and a synchronization mechanism that reduces the difference between the rotational speed of the driving side and the rotational speed of the driven side by frictional force is provided in the first path. It is located. Since the synchronization mechanism is activated to switch between the state in which the first path transmits torque and the state in which the second path transmits torque, the output shaft changes when the torque transmission path changes from the second path to the first path. Torque drop can be reduced. Furthermore, since the synchronization mechanism can reduce the change in rotational speed on the driving side during the gear shifting operation, it is possible to reduce the impact during the gear shifting operation.

According to the second aspect, in the first aspect, when there is relative rotation between the driving side and the driven side and a frictional force is acting on the synchronizing mechanism, the second path is changed to a torque due to an upshift. put it in a state where it can be transmitted. It is possible to reduce the impact when the second path is in a state of transmitting torque.

According to the third aspect, in the first or second aspect, the sleeve provided with the first teeth moves along the axis, and the second teeth that transmit torque between the driving side and the driven side are arranged. It meshes with the first tooth. The first tooth includes a first surface facing one side in the circumferential direction and a second surface facing the other side in the circumferential direction. and a fourth surface that faces at least a portion of the second surface when the first tooth and the second tooth engage with each other. The first surface and the third surface transmit torque in the direction of pressing the first surface and the third surface. The second surface and the fourth surface generate a thrust force that disengages the first tooth and the second tooth according to the torque in the direction of pressing the second surface and the fourth surface. As a result, coasting torque acts between the second tooth and the first tooth, and when the second surface and the fourth surface are pressed, the first tooth and the second tooth can be disengaged.

According to the fourth aspect, in any of the first to third aspects, the dog clutch disposed in the power transmission path for the first speed connects and disconnects the power transmission path. A sleeve provided with a first tooth of a dog clutch moves along the shaft, and a second tooth meshes with the first tooth to transmit torque between the driving side and the driven side. The first tooth includes a first surface facing one side in the circumferential direction and a second surface facing the other side in the circumferential direction. and a fourth surface that faces at least a portion of the second surface when the first tooth and the second tooth engage with each other. The first surface and the third surface include a first portion that transmits a torque in a direction that presses the first surface and the third surface. The second surface and the fourth surface include a second portion that transmits a torque in a direction that presses the second surface and the fourth surface. A shift device that moves the sleeve in the axial direction in which the first tooth and the second tooth engage, moves the sleeve between a first axial position where torque is transmitted in the first part and a second axial position different from the first position. And exercise. In the second position, the second part transmits torque. This allows both drive torque and coasting torque to be transmitted. Furthermore, the meshing between the first tooth and the second tooth can be smoothly released. Further, if the motor is rotated in the opposite direction to the rotation of the motor when rotating the output shaft in a certain direction, the output shaft can be rotated in the opposite direction.

According to the fifth aspect, in any of the first to fourth aspects, the sleeve provided with the first teeth of the dog clutch disposed in the power transmission path moves along the axis, and the second tooth is moved along the shaft. It meshes with the first tooth and transmits torque between the driving side and the driven side. The first tooth includes a first surface facing one side in the circumferential direction and a second surface facing the other side in the circumferential direction. and a fourth surface that faces at least a portion of the second surface when the first tooth and the second tooth engage with each other. The first surface and the third surface transmit torque in the direction of pressing the first surface and the third surface, and the second surface and the fourth surface transmit torque in the direction of pressing the second surface and the fourth surface. A thrust force is generated to release the mesh between the first tooth and the second tooth. The shifting device moves the sleeve in a first axial direction where the first teeth and second teeth engage, and moves the sleeve in a second axial direction where the first teeth and second teeth disengage. During upshifting from a low gear to a high gear, the shift device shifts the first and second teeth of the dog clutch for the low gear when they disengage from each other. Because they interlock, double engagement can be prevented.

According to the sixth aspect, in any of the third to fifth aspects, the first tooth is provided on one end surface of the sleeve in the axial direction. The axial dimension of the transmission can be made shorter than when the first teeth are provided on both axial end faces of the sleeve.

According to the seventh aspect, since the synchronizing mechanism in the first to sixth aspects is a friction clutch, the transmitted torque can be adjusted arbitrarily.

According to the eighth aspect, in the seventh aspect, the power transmission device transmits the output of the actuator to the friction clutch. Since the power transmission efficiency of the power transmission device from the friction clutch to the actuator is negative, the friction clutch can maintain the connected state even if the actuator does not continue to output.

According to the ninth aspect, in any one of the first to sixth aspects, the synchronization mechanism is a synchromesh, so that the difference between the rotational speed on the driving side and the rotational speed on the driven side can be synchronized during the speed change operation.

(a) is a skeleton diagram of the transmission in the first embodiment, and (b) is a schematic side view of the transmission. FIG. 3 is a schematic diagram of a dog clutch. (a) is a schematic diagram of the shift device in the first forward speed, (b) is a schematic diagram of a dog clutch that transmits forward drive torque, and (c) is a diagram of a dog clutch that transmits forward coasting torque. FIG. 3 is a schematic diagram of a clutch, (d) is a schematic diagram of a shift device when traveling in reverse, (e) is a schematic diagram of a dog clutch that transmits drive torque for reverse traveling, and (f) is a schematic diagram of a coasting device when traveling in reverse. FIG. 2 is a schematic diagram of a dog clutch that transmits torque. (a) is a schematic diagram of a dog clutch that transmits drive torque, and (b) is a schematic diagram of a dog clutch that transmits coasting torque. (a) is a skeleton diagram of a transmission in a second embodiment, and (b) is a schematic side view of the transmission. (a) is a skeleton diagram of a transmission in a third embodiment, and (b) is a schematic side view of the transmission. (a) is a schematic diagram of a first tooth and a second tooth in which synchromesh synchronizes, and (b) is a schematic diagram of a dog clutch. (a) is a schematic diagram of the shift device, and (b) is a schematic diagram of the shift device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. A transmission 10 according to a first embodiment will be described with reference to FIGS. 1(a) to 4(b). FIG. 1(a) is a skeleton diagram of the transmission 10 in the first embodiment. FIG. 1(b) is a schematic side view of the transmission 10. Transmission 10 is mounted on a vehicle.

The transmission 10 includes an input shaft 12 to which the power of a motor 11 is input, an output shaft 15 disposed on a different axis from the input shaft 12, and the rotation of the input shaft 12 is transmitted to the output shaft 15 at mutually different gear ratios. A plurality of power transmission paths are provided. The motor 11 is, for example, an electric motor that also functions as a generator. The output shaft 15 is arranged parallel to the input shaft 12, and the first intermediate shaft 13 and the second intermediate shaft 14, which are arranged parallel to the output shaft 15, are arranged on different axes. The rotating shaft of the motor 11 and the input shaft 12 may be integrated, or a transmission element such as a gear pair or a chain may be interposed between the rotating shaft of the motor 11 and the input shaft 12.

A first gear 16 , a friction clutch 17 , and a second gear 21 are arranged on the input shaft 12 . First gear 16 is coupled to input shaft 12 . The friction clutch 17 is a synchronization mechanism that uses frictional force to reduce the difference between the rotational speed on the driving side and the rotational speed on the driven side. In this embodiment, the friction clutch 17 is a wet or dry multi-disc clutch.

The friction clutch 17 includes a drum 18 that is arranged to be relatively rotatable to the input shaft 12, a clutch plate 19 that transmits torque between the drum 18 and the input shaft 12, and a pressing member that presses a relative motion surface of the clutch plate 19. 20, and a return spring (not shown) that applies a force to the pressing member 20 in the direction of interrupting power transmission by the clutch plate 19. The second gear 21 is connected to the drum 18.

When the friction clutch 17 is disengaged, the second gear 21 idles the input shaft 12. When the friction clutch 17 operates and the frictional force generated on the clutch plate 19 increases, the difference between the rotational speed of the input shaft 12 and the rotational speed of the second gear 21 (drum 18) becomes smaller. Depending on the magnitude of the frictional force generated in the clutch plate 19, the second gear 21 may rotate with relative rotation between the input shaft 12 and the second gear 21, or the second gear 21 may rotate in synchronization with the input shaft 12. The second gear 21 rotates together with this. When the friction clutch 17 is engaged, the second gear 21 rotates together with the input shaft 12.

Friction clutch 17 is actuated by actuator 22 . In this embodiment, the actuator 22 is a motor (electric motor). Power transmission device 23 transmits the output of actuator 22 to friction clutch 17 . The power transmission device 23 includes a drive gear 24, a first element 25, and a second element 26.

A drive gear 24 is attached to the rotation shaft of the actuator 22. The drive gear 24 consists of two gears having slightly different numbers of teeth. The torque of the drive gear 24 is transmitted to a first element 25 and a second element 26 that mesh with the drive gear 24. The first element 25 and the second element 26 are supported by the input shaft 12 so as to be relatively rotatable. The gear ratio between drive gear 24 and first element 25 is slightly different from the gear ratio between drive gear 24 and second element 26 . When the drive gear 24 transmits torque to the first element 25 and the second element 26, the first element 25 and the second element 26 rotate slightly relative to each other. The position of the first element 25 in the axial direction (thrust direction) with respect to the input shaft 12 is fixed.

At least one rolling element 27 is disposed between a cam surface provided on the first element 25 and a cam surface provided on the second element 26. Examples of the rolling elements 27 include balls and rollers. The rolling element 27 rolls along the slope between the two cam surfaces due to friction. A return spring (not shown) of the friction clutch 17 presses the second element 26 against the rolling element 27 via the pressing member 20 .

When the actuator 22 is actuated to rotate the drive gear 24 in the forward direction and the first element 25 and second element 26 are rotated relative to each other, the rolling elements 27 roll on the cam surface and press the second element 26 against the pressing member 20. Thrust force is generated. When the second element 26 pushes back the return spring of the friction clutch 17 and the pressing member 20 presses the clutch plate 19, the frictional force generated on the clutch plate 19 increases. When the actuator 22 is actuated to rotate the drive gear 24 in the opposite direction, the frictional force generated on the clutch plate 19 becomes smaller.

The first power transmission efficiency from the actuator 22 to the friction clutch 17 and the second power transmission efficiency from the friction clutch 17 to the actuator 22 of the power transmission device 23 can be set arbitrarily. Note that it is preferable that the second power transmission efficiency is lower than the first power transmission efficiency because rotation of the drive gear 24 due to the torque transmitted from the first element 25 and the second element 26 to the drive gear 24 can be reduced. This is because, after the power transmission device 23 generates a thrust force, the output generated by the actuator 22 to maintain the thrust force can be reduced, so that the power consumption of the actuator 22 can be reduced.

It is more preferable that the second power transmission efficiency is negative. This is because after the power transmission device 23 generates a thrust force, the drive gear 24 can be prevented from rotating even if no current is passed through the actuator 22. The difference between the first power transmission efficiency and the second power transmission efficiency can be set by, for example, the specifications of the gears of the drive gear 24, the first element 25, and the second element 26, and the surface roughness of the tooth surfaces.

A third gear 28 , a fourth gear 29 , and a dog clutch 30 are arranged on the first intermediate shaft 13 . The third gear 28 is coupled to the first intermediate shaft 13. The third gear 28 meshes with the first gear 16 at all times. The fourth gear 29 is arranged to be rotatable relative to the first intermediate shaft 13.

The dog clutch 30 includes a sleeve 31 that rotates together with the first intermediate shaft 13. A shift fork (not shown) is arranged in the sleeve 31. When the shift fork moves along the first intermediate shaft 13, the sleeve 31 slides on the first intermediate shaft 13. A first tooth 32 (see FIG. 2) is provided on one end surface of the sleeve 31 in the axial direction. The length of the first intermediate shaft 13 can be made shorter than when teeth are provided on both end faces in the axial direction of the sleeve 31.

When the first teeth 32 of the sleeve 31 mesh with the second teeth 33 provided on the axial end surface of the fourth gear 29, the fourth gear 29 rotates together with the first intermediate shaft 13. When the first tooth 32 and the second tooth 33 are disengaged, the fourth gear 29 idles on the first intermediate shaft 13.

A fifth gear 34, a sixth gear 35, and a dog clutch 36 are arranged on the second intermediate shaft 14. The fifth gear 34 is coupled to the second intermediate shaft 14 . The fifth gear 34 constantly meshes with the first gear 16. The sixth gear 35 is arranged to be rotatable relative to the second intermediate shaft 14. The sixth gear 35 constantly meshes with the second gear 21.

The dog clutch 36 includes a sleeve 37 that rotates together with the second intermediate shaft 14 . A shift fork (not shown) is arranged in the sleeve 37. When the shift fork moves along the second intermediate shaft 14, the sleeve 37 slides on the second intermediate shaft 14. A first tooth 38 (see FIG. 4(a)) is provided on one end surface of the sleeve 37 in the axial direction. The length of the second intermediate shaft 14 can be made shorter than when teeth are provided on both end faces in the axial direction of the sleeve 37.

When the first teeth 38 of the sleeve 37 mesh with the second teeth 39 provided on the axial end surface of the sixth gear 35, the sixth gear 35 rotates together with the second intermediate shaft 14. When the first tooth 38 and the second tooth 39 are disengaged, the sixth gear 35 idles on the second intermediate shaft 14.

A seventh gear 40 is arranged on the output shaft 15. The seventh gear 40 is coupled to the output shaft 15. The seventh gear 40 constantly meshes with the fourth gear 29 and the sixth gear 35. The output shaft 15 can be used as a wheel attachment shaft, or an output gear can be further arranged on the output shaft 15. When the output shaft 15 is used as a wheel attachment shaft, a differential device is arranged on the output shaft 15, and the seventh gear 40 is coupled to the differential device.

The transmission 10 transmits the rotation of the input shaft 12 to the output shaft 15 at mutually different gear ratios. The gear ratio decreases in the order of 1st gear, 2nd gear, and 3rd gear. When in first speed, the transmission 10 engages the dog clutch 30 and disengages the friction clutch 17 and the dog clutch 36. Transmission 10 transmits rotation to seventh gear 40 via first gear 16, third gear 28, dog clutch 30, and fourth gear 29. When traveling in reverse, the transmission 10 transmits rotation in the opposite direction to the rotation direction when in first gear to the seventh gear 40 via the first gear 16, third gear 28, dog clutch 30, and fourth gear 29. to communicate.

When in second gear, the transmission 10 engages the dog clutch 36 and disengages the friction clutch 17 and the dog clutch 30. Transmission 10 transmits rotation to seventh gear 40 via first gear 16 , fifth gear 34 , dog clutch 36 , and sixth gear 35 .

When in third gear, the transmission 10 engages the friction clutch 17 and disengages the dog clutches 30, 36. The transmission 10 transmits rotation to the seventh gear 40 via the friction clutch 17, the second gear 21, and the sixth gear 35. The power transmission path of the friction clutch 17, the second gear 21, the sixth gear 35, and the seventh gear 40 in the third gear is referred to as a first path, and the power transmission path of the first gear 16, the fifth gear 34, and the mesh in the second gear is referred to as a first path. The power transmission path between the clutch 36, the sixth gear 35, and the seventh gear 40 is referred to as a second path.

FIG. 2 is a schematic diagram of the dog clutch 30. FIG. 2 schematically shows the first tooth 32 provided on the sleeve 31, the second tooth 33 provided on the fourth gear 29, and the shift device 41 when the sleeve 31 and the fourth gear 29 are viewed from the direction perpendicular to the axis. Illustrated in. Arrow F in FIG. 2 indicates the direction in which the sleeve 31 rotates when the vehicle moves forward, and arrow R indicates the direction in which the sleeve 31 rotates when the vehicle moves backward. The shift device 41 sets the axial position of the sleeves 31, 37. Hereinafter, a portion of the shift device 41 that sets the position of the sleeve 31 will be explained.

The shift device 41 includes a shift fork (not shown) attached to the sleeve 31, a shift rod 31a coupled to the shift fork, and a shift drum 42. The shift drum 42 is rotated around the central axis O by an actuator (not shown) such as a motor. A cam groove 43 is provided on the outer periphery of the shift drum 42. A protrusion 44 provided on the shift rod 31a is inserted into the cam groove 43.

The shift drum 42 rotates based on an operation signal from a shift lever (not shown), or based on an accelerator opening degree and vehicle speed signal generated by operation of an accelerator pedal (not shown). When the shift drum 42 (cylindrical cam) rotates, the sleeve 31 moves in the axial direction via the shift rod 31a, which has a protrusion 44 guided in a cam groove 43.

The shift device 41 includes a spring mechanism 41a. In this embodiment, the spring mechanism 41a includes a plurality of recesses 41b provided on the outer periphery of the shift rod 31a, a ball 41c that engages with the recess 41b, and a spring 41d that presses the ball 41c against the recess 41b with elastic force. We are prepared. The recess 41b has inclined surfaces facing each other in the axial direction.

When the sleeve 31 is in the neutral position and when the first tooth 32 and the second tooth 33 provided on the sleeve 31 are most deeply engaged, the ball 41c is located at the bottom of the recess 41b. When the ball 41c runs over or rides over the inclined surface of the recess 41b, the spring 41d applies an axial force to the shift rod 31a. The spring mechanism 41a assists in positioning the sleeve 31 in the axial direction and assists in disengaging the first tooth 32 and the second tooth 33 by the elastic force of the spring 41d.

A plurality of first teeth 32 are arranged around the central axis of the sleeve 31 at intervals in the circumferential direction. The first tooth 32 includes a first surface 45 facing one circumferential direction and a second surface 49 facing the other circumferential direction. A plurality of second teeth 33 are arranged around the central axis of the fourth gear 29 at intervals in the circumferential direction. The second tooth 33 includes a fourth surface 55 facing one circumferential direction and a third surface 53 facing the other circumferential direction. The third surface 53 faces at least a portion of the first surface 45 when the sleeve 31 moves in the axial direction and the first tooth 32 and the second tooth 33 engage with each other. The fourth surface 55 faces at least a portion of the second surface 49 when the sleeve 31 moves in the axial direction and the first tooth 32 and the second tooth 33 engage with each other.

The first surface 45 includes a first portion 46 that transmits a torque in a direction that presses the first surface 45 and the third surface 53, and a fifth portion 47 adjacent to the dedendum side of the first portion 46. The first portion 46 is inclined so as to approach the second surface 49 as it goes toward the root of the tooth. The first portion 46 transmits torque in the direction of pressing the first surface 45 and the third surface 53 together. The fifth portion 47 is inclined away from the second surface 49 toward the root of the tooth. The fifth portion 47 generates a thrust force that separates the fourth gear 29 and the sleeve 31 in the axial direction according to the torque that presses the first surface 45 and the third surface 53 together.

The third surface 53 includes a first portion 54 that transmits torque in the direction of pressing the first surface 45 and the third surface 53 together. The first portion 54 is inclined so as to approach the fourth surface 55 as it goes toward the root of the tooth. The first portions 46 and 54 transmit torque in the direction of pressing the first surface 45 and the third surface 53 (forward drive torque).

The second surface 49 includes a second part 50, a third part 52 located on the tooth tip side of the second part 50, and a fourth part 51 located between the second part 50 and the third part 52. including. The second portion 50 is inclined away from the first surface 45 toward the tooth tip. The third portion 52 is inclined so as to approach the first surface 45 toward the tooth tip. The fourth part 51 connects the second part 50 and the third part 52.

The fourth surface 55 includes a second portion 56, a third portion 58 located on the root side of the second portion 56, and a fourth portion 57 located between the second portion 56 and the third portion 58. including. The second portion 56 is inclined so as to approach the third surface 53 as it goes toward the root of the tooth. The third portion 58 is inclined away from the third surface 53 toward the root of the tooth. The fourth part 57 connects the second part 56 and the third part 58. The second portions 50 and 56 transmit torque in the direction of pressing the second surface 49 and the fourth surface 55 (reverse drive torque). The third parts 52 and 58 generate a thrust force that separates the fourth gear 29 and the sleeve 31 in the axial direction according to the torque in the direction of pressing the second surface 49 and the fourth surface 55 (forward coasting torque). .

Referring to FIGS. 3(a) to 3(f), the operation of the transmission 10 when the first tooth 32 and the second tooth 33, which transmit torque for the first forward speed, reverse speed, and first forward speed, are disengaged. Explain. 3(a) to 3(c) show the state of first forward speed and reverse movement, and FIG. 3(d) to FIG. 3(f) show the state when the first tooth 32 and the second tooth 33 are disengaged. Indicates the condition.

The shift drum 42 has a central axis O of the shift drum 42 parallel to the shift rod 31a (see FIG. 2), the input shaft 12 (see FIG. 1), the first intermediate shaft 13, the second intermediate shaft 14, and the output shaft 15. It is located. "N" shown in FIGS. 3(a) and 3(d) represents neutral, "1" represents first gear, and "R" represents reverse gear. Arrows F in FIGS. 3(b), 3(c), 3(e), and 3(f) indicate the direction in which the sleeve 31 rotates when moving forward, and arrow R indicates the direction in which the sleeve 31 rotates when moving backward. Indicates the direction of rotation.

When the shift drum 42 rotates around the central axis O, the protrusion 44 moves along the cam groove 43, and the shift rod 31a and sleeve 31 move in the axial direction accordingly. When the protrusion 44 is located in the "N" portion of the cam groove 43, the first tooth 32 does not mesh with the second tooth 33. When the protrusion 44 is located at the "1" or "R" portion of the cam groove 43, the first tooth 32 meshes with the second tooth 33 (FIG. 3(a)).

As shown in FIG. 3(b), when the forward drive torque is transmitted from the first tooth 32 to the second tooth 33, the fifth portion 47 generates a torque in the direction of pressing the first surface 45 and the third surface 53. Accordingly, a thrust force is generated to separate the fourth gear 29 and the sleeve 31 in the axial direction, and the sleeve 31 is positioned at a position where the first portion 46 of the first tooth 32 contacts the first portion 54 of the second tooth 33. This position is called the first position. The spring mechanism 41a (see FIG. 2) stores elastic energy that brings the sleeve 31 closer to the fourth gear 29 due to the thrust force generated by the fifth portion 47 that separates the fourth gear 29 and the sleeve 31 in the axial direction. The first tooth 32 and the second tooth 33 press the first portions 46 and 54 to transmit forward drive torque.

As shown in FIG. 3(c), when forward coasting torque acts on the first tooth 32 and the second tooth 33, the second surface 49 of the first tooth 32 and the fourth surface 55 of the second tooth 33 While the first tooth 32 and the second tooth 33 rotate relative to each other by the circumferential gap between them, the shift rod 31a is moved by an axial elastic force caused by releasing the elastic energy stored in the spring mechanism 41a, The sleeve 31 approaches the fourth gear 29 by the amount of the gap between the cam groove 43 and the protrusion 44 in the "1" portion. As a result, the sleeve 31 is positioned at a position where the second portion 56 of the second tooth 33 contacts the second portion 50 of the first tooth 32 . This position is called the second position. The first tooth 32 and the second tooth 33 press against the second portions 50 and 56 to transmit forward coasting torque. This makes it possible to secure regenerative energy by the motor 11 when forward coasting torque is transmitted.

As shown in FIG. 3(d), when shifting up from 1st forward speed to 2nd forward speed, the shift device 41 rotates the shift drum 42 (in the direction of the arrow) to The protrusion 44 located at is brought closer to the “N” portion, and the friction clutch 17 (see FIG. 1) is further rotationally engaged to transmit a portion of the torque of the input shaft 12 from the second gear 21 to the sixth gear 35. When the rotation of the sixth gear 35 is transmitted to the seventh gear 40, the fourth gear 29 rotates, and the rotational speed of the fourth gear 29 becomes higher than the rotational speed of the sleeve 31 due to the difference in gear ratio. As a result, a forward coasting torque acts on the first tooth 32 and the second tooth 33.

When the protrusion 44 and the shift rod 31a move in the axial direction along the slope of the cam groove 43, and the sleeve 31 is located at a position where the third portion 58 of the first tooth 32 contacts the third portion 52 of the second tooth 33, The third portions 52 and 58 are brought into contact with each other and generate a thrust force that separates the fourth gear 29 and the sleeve 31 in the axial direction according to the torque in the direction of pressing the second surface 49 and the fourth surface 55. As the shift drum 42 rotates, the first tooth 32 and the second tooth 33 are smoothly disengaged (FIG. 3(f)).

When moving backward, the shift drum 42 rotates and the protrusion 44 is positioned at the "R" portion of the cam groove 43. As a result, the sleeve 31 is located at the second position where the second portion 50 of the first tooth 32 contacts the second portion 56 of the second tooth 33 . When moving backward, the motor 11 rotates in the opposite direction to the rotation when moving forward. The first tooth 32 and the second tooth 33 press against the second portions 50 and 56 to transmit reverse drive torque (FIG. 3(c)).

When a backward coasting torque acts on the first tooth 32 and the second tooth 33, the third surface 53 of the second tooth 33 comes into contact with the first surface 45 of the first tooth 32 (FIG. 3(b)). When the third surface 53 comes into contact with the fifth portion 47 of the first surface 45, the fifth portion 47 of the first surface 45 moves into the fourth portion according to the torque that presses the first surface 45 and the third surface 53. A thrust force is generated to separate the gear 29 and the sleeve 31 in the axial direction. The protrusion 44 and the shift rod 31a move in the axial direction by the amount of the gap between the cam groove 43 and the protrusion 44 in the "R" portion, setting the sleeve 31 at the first position. The restoring force of the spring mechanism 41a contributes to maintaining the meshing between the first tooth 32 and the second tooth 33. The first teeth 32 and the second teeth 33 press against the first portions 46 and 54 to transmit coasting torque for reverse movement. Therefore, regenerative energy by the motor 11 can be secured. The restoring force of the spring mechanism 41a may be used for the thrust force that separates the sleeve 31 from the fourth gear 29.

According to the transmission 10, the shift device 41 sets the sleeve 31 at the first position or the second position where the first teeth 32 and the second teeth 33 engage, and the first teeth 32 and the second teeth 33 engage with each other. By changing the meshing position, both drive torque and coasting torque can be transmitted. Further, the first tooth 32 and the second tooth 33 can be smoothly disengaged from each other. Further, by rotating the motor 11 in the opposite direction to the rotation for the first speed (forward), the vehicle can move backward. Therefore, a mechanism such as a reverse gear can be omitted.

4(a) and 4(b) are schematic diagrams of the dog clutch 36. 4(a) and 4(b), when the sleeve 37 and the sixth gear 35 are viewed from the direction perpendicular to the axis, the first tooth 38 provided on the sleeve 37 and the first tooth 38 provided on the sixth gear 35 are shown. A second tooth 39 is schematically illustrated. Arrow F in FIGS. 4(a) and 4(b) indicates the direction in which the sleeve 37 rotates.

A plurality of first teeth 38 are arranged around the central axis of the sleeve 37 at intervals in the circumferential direction. The first tooth 38 includes a first surface 59 facing one circumferential direction and a second surface 60 facing the other circumferential direction. A plurality of second teeth 39 are arranged around the central axis of the sixth gear 35 at intervals in the circumferential direction. The second tooth 39 includes a fourth surface 65 facing one circumferential direction and a third surface 64 facing the other circumferential direction. The third surface 64 faces at least a portion of the first surface 59 when the sleeve 37 moves axially and the first tooth 38 and the second tooth 39 engage. The fourth surface 65 faces at least a portion of the second surface 60 when the sleeve 37 moves axially and the first tooth 38 and the second tooth 39 engage.

The first surface 59 is inclined so as to approach the second surface 60 as it goes toward the root of the tooth. The third surface 64 is inclined so as to approach the fourth surface 65 as it goes toward the root of the tooth. The first surface 59 and the third surface 64 transmit torque (drive torque) in the direction of pressing the first surface 59 and the third surface 64 together.

The second surface 60 includes a seventh part 61 , a third part 63 located on the tooth tip side of the seventh part 61 , and a fourth part 62 located between the seventh part 61 and the third part 63 . including. The seventh portion 61 and the third portion 63 are inclined so as to approach the first surface 59 toward the tooth tip. The fourth part 62 connects the seventh part 61 and the third part 63.

The fourth surface 65 includes a seventh portion 66, a third portion 68 located on the root side of the seventh portion 66, and a fourth portion 67 located between the seventh portion 66 and the third portion 68. including. The seventh portion 66 and the third portion 68 are inclined away from the third surface 64 toward the root of the tooth. The fourth part 67 connects the seventh part 66 and the third part 68. The seventh portions 61 and 66 generate a thrust force that separates the sixth gear 35 and the sleeve 37 in the axial direction according to the torque (coasting torque) in the direction of pressing the second surface 60 and the fourth surface 65 together.

Returning to FIG. 1(a), the gear shifting operation of the transmission 10 will be described. When in first speed, the transmission 10 transmits rotation to the seventh gear 40 via the first gear 16, third gear 28, dog clutch 30, and fourth gear 29. As the first gear 16 rotates, the fifth gear 34 that meshes with the first gear 16 and the second intermediate shaft 14 also rotate. The sixth gear 35 that meshes with the seventh gear 40 rotates relatively around the second intermediate shaft 14, and the second gear 21 that meshes with the sixth gear 35 rotates relatively around the input shaft 12.

To shift from 1st speed to 2nd speed, firstly, the friction clutch 17 is operated while sliding, and a portion of the torque of the input shaft 12 is transferred to the second gear while there is relative rotation between the driving side and the driven side. 21 to the sixth gear 35. When the rotation of the sixth gear 35 is transmitted to the seventh gear 40, the fourth gear 29 rotates, and the rotational speed of the fourth gear 29 becomes higher than the rotational speed of the sleeve 31 due to the difference in gear ratio. When the first part 46 of the first tooth 32 and the first part 54 of the second tooth 33 are separated and the third part 58 of the second tooth 33 is pressed against the third part 52 of the first tooth 32 (see FIG. e)) A thrust force is generated that separates the fourth gear 29 and the sleeve 31 in the axial direction, and the first tooth 32 and the second tooth 33 are disengaged (FIG. 3(f)).

When the difference between the rotation speed of the sleeve 37 of the dog clutch 36 and the rotation speed of the sixth gear 35 becomes small, the sleeve 37 is moved in the axial direction, and the first teeth 38 and the second teeth 39 are brought into mesh with each other. When the dog clutch 36 is engaged and the friction clutch 17 is disengaged at the same time, a second speed is established in which rotation is transmitted to the seventh gear 40 via the first gear 16, the fifth gear 34, the dog clutch 36, and the sixth gear 35. Since a portion of the torque of the input shaft 12 is transmitted to the output shaft 15 by the friction clutch 17, a decrease in the torque of the output shaft 15 during a gear shifting operation can be reduced, and a seamless shift can be realized.

In a shift operation from second speed to third speed, the friction clutch 17 is connected and the torque of the input shaft 12 is transmitted from the second gear 21 to the sixth gear 35. When the rotational speed of the sixth gear 35 becomes higher than the rotational speed of the sleeve 37 due to the difference in speed ratio, the first surface 59 of the first tooth 38 and the third surface 64 of the second tooth 39 are separated. When the seventh part 66 of the second tooth 39 is pressed against the seventh part 61 of the first tooth 38 (FIG. 4(b)), a thrust is generated that separates the sixth gear 35 and the sleeve 37 in the axial direction. The first tooth 38 and the second tooth 39 are disengaged. This establishes the third speed in which rotation is transmitted to the seventh gear 40 via the friction clutch 17, second gear 21, and sixth gear 35.

Since torque is transmitted to the output shaft 15 by the friction clutch 17 during a shift operation from the second speed to the third speed, a decrease in the torque of the output shaft 15 can be reduced and a seamless shift can be realized. Since the friction clutch 17 is connected to switch from second speed to third speed, it is possible to reduce the impact during the speed change operation.

Since the friction clutch 17 is arranged on the first path where the gear position with the smallest gear ratio (3rd speed in this embodiment) is established when the friction clutch 17 is connected, the friction clutch 17 is used to control the drive side of the first path. The relative speed between the motor and the driven side can be synchronized. Therefore, it is possible to easily switch from the second path (in this embodiment, the second speed power transmission path) to the first path when upshifting.

Since the friction clutch 17 is disposed on the input shaft 12 to which the motor 11 is connected, the transmission 10 and the motor 11 can be disconnected by disengaging the friction clutch 17. By disconnecting the motor 11, the moment of inertia of the transmission 10 can be reduced, and the impact during the speed change operation can be reduced.

In the transmission 10, one clutch (friction clutch 17 and dog clutches 30, 36) is disposed on each of the input shaft 12, the first intermediate shaft 13, and the second intermediate shaft 14. Therefore, the axial length of the transmission 10 can be made shorter than when two or more clutches are arranged side by side on each shaft.

When in first gear, rotation is transmitted to seventh gear 40 via first gear 16, third gear 28, and fourth gear 29, and when in second gear, rotation is transmitted to seventh gear 40 via first gear 16, third gear 28, and fourth gear 29. The rotation is transmitted to the seventh gear 40 via the sixth gear 35, and when the gear is in third speed, the rotation is transmitted to the seventh gear 40 via the second gear 21 and the sixth gear 35. Since the transmission 10 transmits rotation to the seventh gear 40 through two or three gears, it can be downsized.

A transmission 70 in a second embodiment will be described with reference to FIGS. 5(a) and 5(b). In the first embodiment, a case has been described in which the friction clutch 17 is disposed in the power transmission path in the third gear. On the other hand, in the second embodiment, a case will be described in which the friction clutch 17 is disposed in the power transmission path in the second gear. The same parts as in the first embodiment are given the same reference numerals and the following explanation is omitted. FIG. 5(a) is a skeleton diagram of a transmission 70 in the second embodiment. FIG. 5(b) is a schematic side view of the transmission 70.

The transmission 70 transmits the rotation of the input shaft 12 to the output shaft 15 at mutually different gear ratios. When in first speed, the transmission 70 engages the dog clutch 30 and disengages the friction clutch 17 and the dog clutch 36. Transmission 70 transmits rotation to seventh gear 40 via first gear 16 , third gear 28 , dog clutch 30 , and fourth gear 29 . When traveling in reverse, the transmission 70 transmits rotation in the opposite direction to the rotation direction when in first gear to the seventh gear 40 via the first gear 16, third gear 28, dog clutch 30, and fourth gear 29. to communicate.

When in second gear, the transmission 70 engages the friction clutch 17 and disengages the dog clutches 30 and 36. The transmission 70 transmits rotation to the seventh gear 40 via the friction clutch 17, the second gear 21, and the sixth gear 35.

When in third speed, the transmission 70 engages the dog clutch 36 and disengages the friction clutch 17 and the dog clutch 30. Transmission 70 transmits rotation to seventh gear 40 via first gear 16 , fifth gear 34 , dog clutch 36 , and sixth gear 35 .

The power transmission path between the friction clutch 17, the second gear 21, the sixth gear 35, and the seventh gear 40 in the second gear is referred to as a first path, and the power transmission path of the first gear 16, the fifth gear 34, and the mesh in the third gear is referred to as a first path. The power transmission path between the clutch 36, the sixth gear 35, and the seventh gear 40 is referred to as a second path. The gear ratio decreases in the order of 1st gear, 2nd gear, and 3rd gear.

When in first speed, the transmission 70 transmits rotation to the seventh gear 40 via the first gear 16, the third gear 28, the dog clutch 30, and the fourth gear 29. As the first gear 16 rotates, the fifth gear 34 that meshes with the first gear 16 and the second intermediate shaft 14 also rotate. The sixth gear 35 that meshes with the seventh gear 40 rotates relatively around the second intermediate shaft 14, and the second gear 21 that meshes with the sixth gear 35 rotates relatively around the input shaft 12.

To shift from the first gear to the second gear, the friction clutch 17 is engaged and the torque of the input shaft 12 is transmitted from the second gear 21 to the sixth gear 35. When the rotation of the sixth gear 35 is transmitted to the seventh gear 40, the fourth gear 29 rotates, and the rotational speed of the fourth gear 29 becomes higher than the rotational speed of the sleeve 31 due to the difference in gear ratio. When the first part 46 of the first tooth 32 and the first part 54 of the second tooth 33 are separated and the third part 58 of the second tooth 33 is pressed against the third part 52 of the first tooth 32 (see FIG. e)) A thrust force is generated that separates the fourth gear 29 and the sleeve 31 in the axial direction, and the first tooth 32 and the second tooth 33 are disengaged (FIG. 3(f)). This establishes the second speed in which rotation is transmitted to the seventh gear 40 via the friction clutch 17, second gear 21, and sixth gear 35.

In the shift operation from 2nd speed to 3rd speed, the difference between the rotational speed of the sleeve 37 of the dog clutch 36 and the rotational speed of the 6th gear 35 is reduced while disengaging the friction clutch 17 (reducing the frictional force). When the sleeve 37 is moved in the axial direction, the first teeth 38 and the second teeth 39 are engaged with each other. When the dog clutch 36 is engaged and the friction clutch 17 is disengaged at the same time, a third speed is established in which rotation is transmitted to the seventh gear 40 via the first gear 16, the fifth gear 34, the dog clutch 36, and the sixth gear 35. Seamless shifting can also be achieved in the transmission 70 as in the first embodiment.

A transmission 71 according to the third embodiment will be described with reference to FIGS. 6(a) to 8(b). In the first embodiment and the second embodiment, the case where the friction clutch 17 is arranged has been described. On the other hand, in the third embodiment, a case where synchromesh is arranged will be described. The same parts as in the first embodiment are given the same reference numerals and the following explanation is omitted. FIG. 6(a) is a skeleton diagram of a transmission 71 in the third embodiment. FIG. 6(b) is a schematic side view of the transmission 71.

A first gear 16 , a second gear 21 , and a synchromesh 72 are arranged on the input shaft 12 of the transmission 71 . The synchromesh 72 is a synchronization mechanism that uses frictional force to reduce the difference between the rotational speed of the sleeve 73 that rotates together with the input shaft 12 and the rotational speed of the second gear 21. Examples of the mechanism of the synchromesh 72 include a constant load type and an inertia lock type, but the mechanism is not limited. Since the synchromesh 72 generates small friction torque (drag torque) when the synchromesh 72 is not activated, energy loss due to drag torque can be reduced.

A shift fork (not shown) is arranged in the sleeve 73. When the shift fork moves along the input shaft 12, the sleeve 73 slides on the input shaft 12. First teeth 74 (see FIG. 7(a)) are provided on the inner periphery of the sleeve 73. The second gear 21 is arranged to be rotatable relative to the input shaft 12. A second tooth 75 (see FIG. 7(a)) that meshes with the first tooth 74 is provided on the outer periphery of the second gear 21.

The dog clutch 76 disposed on the second intermediate shaft 14 has a function of transmitting and interrupting power between the second intermediate shaft 14 and the sixth gear 35. The dog clutch 76 includes a sleeve 37 that rotates together with the second intermediate shaft 14 . A shift fork (not shown) is arranged in the sleeve 37. A first tooth 38 (see FIG. 7(b)) is provided on one end surface of the sleeve 37 in the axial direction.

FIG. 7A is a schematic diagram of the first tooth 74 and the second tooth 75 with which the synchromesh 72 is synchronized. In FIG. 7(a), the first tooth 74 provided on the sleeve 73 and the second tooth 75 provided on the second gear 21 are schematically shown when the sleeve 73 and the second gear 21 are viewed from the direction perpendicular to the axis. Illustrated. Arrow F indicates the direction in which sleeve 73 rotates as the vehicle moves forward.

A plurality of first teeth 74 are arranged around the central axis of the sleeve 73 at intervals in the circumferential direction. The first tooth 74 includes a first surface 77 facing one circumferential direction and a second surface 78 facing the other circumferential direction. A plurality of second teeth 75 are arranged around the central axis of the second gear 21 at intervals in the circumferential direction. The second tooth 75 includes a fourth surface 80 facing one circumferential direction, and a third surface 79 facing the other circumferential direction. The third surface 79 faces at least a portion of the first surface 77 when the sleeve 73 moves in the axial direction and the first tooth 74 and the second tooth 75 engage with each other. The fourth surface 80 faces at least a portion of the second surface 78 when the sleeve 73 moves in the axial direction and the first teeth 74 and the second teeth 75 engage.

The first surface 77 and the second surface 78 are inclined with respect to the central axis of the sleeve 73. The third surface 79 and the fourth surface 80 are inclined with respect to the central axis of the second gear 21. The first surface 77 of the first tooth 74 and the third surface 79 of the second tooth 75 transmit torque (drive torque) in the direction of pressing the first surface 77 and the third surface 79 together. The second surface 78 of the first tooth 74 and the fourth surface 80 of the second tooth 75 are connected to the second gear 21 and the sleeve according to the torque (coasting torque) in the direction of pressing the second surface 78 and the fourth surface 80. A thrust force is generated that separates 73 in the axial direction.

FIG. 7(b) is a schematic diagram of the dog clutch 76. In FIG. 7(b), the first tooth 38 provided on the sleeve 37 and the second tooth 39 provided on the sixth gear 35 are schematically shown when the sleeve 37 and the sixth gear 35 are viewed from the direction perpendicular to the axis. Illustrated. Arrow F in FIG. 7(b) indicates the direction in which the sleeve 37 rotates.

The first tooth 38 includes a first surface 81 facing one circumferential direction, and a second surface 60 facing the other circumferential direction. The first surface 81 includes a first portion 82 and an eighth portion 83 adjacent to the dedendum side of the first portion 82 . The first portion 82 is inclined so as to approach the second surface 60 as it goes toward the root of the tooth. The first portion 82 and the third surface 64 transmit torque (drive torque) in the direction of pressing the first surface 81 and the third surface 64 together. The eighth portion 83 is inclined away from the second surface 60 toward the root of the tooth. The eighth portion 83 and the third surface 64 generate a thrust force that separates the sixth gear 35 and the sleeve 37 in the axial direction according to the torque in the direction of pressing the first surface 81 and the third surface 64.

The transmission 71 transmits the rotation of the input shaft 12 to the output shaft 15 at mutually different gear ratios. The gear ratio decreases in the order of 1st gear, 2nd gear, and 3rd gear. When in first gear, the transmission 71 engages the dog clutch 30, disengages the dog clutch 76, and disengages the first tooth 74 and the second tooth 75. Transmission 71 transmits rotation to seventh gear 40 via first gear 16 , third gear 28 , dog clutch 30 , and fourth gear 29 .

When in second speed, the transmission 71 engages the dog clutch 76, disengages the dog clutch 30, and disengages the first teeth 74 and second teeth 75. Transmission 71 transmits rotation to seventh gear 40 via first gear 16 , fifth gear 34 , dog clutch 76 , and sixth gear 35 .

When in third speed, the transmission 71 engages the first tooth 74 and the second tooth 75 and disengages the dog clutches 30 and 76. The transmission 71 transmits rotation to the seventh gear 40 via the second gear 21 and the sixth gear 35. The power transmission path between the second gear 21, the sixth gear 35, and the seventh gear 40 in the third gear is called a first path, and the power transmission path between the second gear 21, the sixth gear 35, and the seventh gear 40 in the second gear The power transmission path between the sixth gear 35 and the seventh gear 40 is referred to as a second path.

The operation of the transmission 71 during upshifting will be described with reference to FIG. 8(a), and the operation of the transmission 71 during downshifting will be described with reference to FIG. 8(b). FIGS. 8(a) and 8(b) are schematic diagrams of the shift device 41 (shift drum 42).

The shift drum 42 is provided with cam grooves 84 and 85 on its outer periphery. A protrusion 86 that is coupled to a shift fork (not shown) disposed on the sleeve 73 (synchromesh 72) is inserted into the cam groove 84. A protrusion 87 that is coupled to a shift fork (not shown) disposed on the sleeve 37 (meshing clutch 76) is inserted into the cam groove 85. "S" shown in FIG. 8(a) indicates synchronization by the synchromesh 72, "3" indicates the third gear, "2" indicates the second gear, and the arrow indicates the rotation direction of the shift drum 42 at the time of upshifting.

As shown in FIG. 8(a), when the projections 44, 86, 87 are present in the first region 88 of the shift drum 42, the dog clutch 30 is engaged, the dog clutch 76 is disengaged, and the first tooth 74 and second tooth The mesh with 75 is disengaged (1st gear). At the boundary between the first region 88 and the second region 89, the sleeve 31 (dog clutch 30) is slightly separated from the fourth gear 29 by the protrusion 44 moving in the cam groove 43, and the second tooth 33 ( The tip of the first portion 54 (see FIG. 2) is located at the first portion 46 of the first tooth 32. This is to smoothly disengage the first tooth 32 and the second tooth 33.

When the protrusions 44, 86, 87 in the second region 89 move toward the third region 90, the synchromesh 72 is actuated by the cam groove 84, and a part of the torque of the input shaft 12 is absorbed by the frictional force of the synchromesh 72. It is transmitted from the second gear 21 to the sixth gear 35. When the rotation of the sixth gear 35 is transmitted to the seventh gear 40, the fourth gear 29 rotates, and the rotational speed of the fourth gear 29 becomes higher than the rotational speed of the sleeve 31 due to the difference in gear ratio. When the first part 46 of the first tooth 32 and the first part 54 of the second tooth 33 are separated and the third part 58 of the second tooth 33 is pressed against the third part 52 of the first tooth 32 (see FIG. e)) A thrust force is generated that separates the fourth gear 29 and the sleeve 31 in the axial direction. As the protrusion 44 moves within the cam groove 43, the dog clutch 30 is disengaged.

When the projections 44, 86, 87 in the third region 90 move toward the fourth region 91, the sleeve 37 of the dog clutch 76 moves in the axial direction as the projection 87 in the cam groove 85 moves. Since the difference between the rotational speed of the sleeve 37 and the rotational speed of the sixth gear 35 at this time is small, the dog clutch 76 is smoothly engaged. At the same time, when the synchromesh 72 stops operating as the protrusion 86 in the cam groove 84 moves, the transmission 71 shifts to the seventh gear via the first gear 16, fifth gear 34, dog clutch 76, and sixth gear 35. 40 (2nd speed). Since a part of the torque of the input shaft 12 is transmitted to the output shaft 15 by the synchromesh 72 during a shift operation, a decrease in the torque of the output shaft 15 during a shift operation is reduced, and a seamless shift can be realized.

When the protrusions 44, 86, 87 in the fourth region 91 move toward the fifth region 92, the synchromesh 72 operates as the protrusion 86 in the cam groove 84 moves, so the sleeve The first teeth 74 of the gear 73 and the second teeth 75 of the second gear 21 mesh with each other. At the same time, the torque of the input shaft 12 is transmitted from the second gear 21 to the sixth gear 35 due to the frictional force of the synchromesh 72.

When the rotational speed of the sixth gear 35 becomes higher than the rotational speed of the sleeve 37 due to the difference in speed ratio, the first surface 59 of the first tooth 38 and the third surface 64 of the second tooth 39 are separated. When the seventh portion 66 of the second tooth 39 is pressed against the seventh portion 61 of the first tooth 38 (FIG. 4(b)), a thrust force is generated that separates the sixth gear 35 and the sleeve 37 in the axial direction. At the boundary between the fourth region 91 and the fifth region 92, the sleeve 37 (meshing clutch 76) is slightly separated from the sixth gear 35 by the protrusion 87 moving in the cam groove 85, and the second tooth 39 ( The tip of the third surface 64 (see FIG. 7(b)) is located at the boundary between the eighth portion 83 and the first portion 82 of the first tooth 38. This is to smoothly disengage the first tooth 38 and the second tooth 39.

When the projections 44, 86, 87 in the fifth region 92 move in a direction away from the fourth region 91, the dog clutch 76 is disengaged as the projection 87 in the cam groove 85 moves. As a result, rotation is transmitted to the seventh gear 40 via the second gear 21 and the sixth gear 35 (third speed). Since torque is transmitted to the output shaft 15 by the synchromesh 72 during a shift operation from 2nd speed to 3rd speed, a decrease in the torque of the output shaft 15 during a shift operation can be reduced and a seamless shift can be realized. Since the relative speed between the driving side and the driven side is reduced by the frictional force of the synchromesh 72, it is possible to reduce the impact during the gear shifting operation.

The shape of the cam grooves 43, 84, 85 of the shift drum 42 is such that when the first tooth 38 and the second tooth 39 of the dog clutch 76 for the low speed are disengaged during upshifting from a low speed to a high speed. The first teeth 74 and second teeth 75 for the high speed stage are set to mesh with each other. Therefore, double engagement can be prevented.

The arrow in FIG. 8(b) indicates the rotation direction of the shift drum 42 during downshifting. When the projections 44, 86, 87 are present in the sixth region 93 of the shift drum 42, third speed is established. When the protrusions 44, 86, and 87 are present in the eighth region 95, second speed is established. When the protrusions 44, 86, 87 in the tenth region 97 are present, the first speed is established. When the protrusions 44, 86, 87 in the seventh region 94 move toward the eighth region 95, a downshift from third gear to second gear is performed. The first tooth 74 and the second tooth 75 that are separated when downshifting from 3rd gear to 2nd gear (see FIG. 7(a)) are such that the second surface 78 and the fourth surface 80 are A thrust force is generated to separate the second gear 21 and the sleeve 73 in the axial direction according to the torque in the direction of pressing the surface 80 (coasting torque). This allows for seamless downshifts.

When the protrusions 44, 86, and 87 in the ninth region 96 move toward the tenth region 97, a downshift from second gear to first gear is performed. The first tooth 38 and the second tooth 39, which are separated when downshifting from 2nd speed to 1st speed (see FIG. 7(b)), have third parts 63 and 68 that are connected to the second surface 60 and the fourth surface 65. A thrust force is generated to separate the sixth gear 35 and the sleeve 37 in the axial direction according to the torque (coasting torque) in the direction of pressing the sixth gear 35 and the sleeve 37. This allows for seamless downshifts.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. This can be easily inferred.

In the embodiment, the torque of the input shaft 12 is transferred to the first intermediate shaft 13 and the second intermediate shaft by the first gear 16, the second gear 21, the third gear 28, the fourth gear 29, the fifth gear 34, and the sixth gear 35. Although the case where the information is transmitted to 14 has been described, it is not necessarily limited to this. It is of course possible to employ transmission elements other than gears in the transmissions 10, 70, 71. Examples of transmission elements other than gears include chains, sprockets, belts, and pulleys.

In the embodiment, a transmission having a mechanism of three forward speeds and one reverse speed has been described, but the invention is not necessarily limited to this. It is of course possible to apply the technology in the embodiment to a transmission having a mechanism with two forward speeds or four or more forward speeds. The number of intermediate shafts disposed between the input shaft 12 and the output shaft 15 can be set as appropriate depending on the number of gear stages.

In the embodiment, the friction clutch 17 has been described by exemplifying a multi-plate clutch, but the invention is not necessarily limited to this. It is of course possible to employ other friction clutches. Examples of other friction clutches include a single plate clutch and a conical clutch.

In the embodiment, a gear provided on the first element 25 and a gear provided on the second element 26 are meshed with the drive gear 24 through which the torque of the actuator 22 is transmitted, and the drive gear 24 has a negative power transmission coefficient. Although the transmission device 23 has been described, it is not necessarily limited to this. It is of course possible to employ other power transmission devices with negative power transmission coefficients. Examples of other power transmission devices include one in which a screw with high friction is provided between the first element 25 and the second element 26, and a worm gear.

In the embodiment, a case has been described in which the fifth portion 47 is provided on the first surface 45 of the first tooth 32, but the present invention is not necessarily limited to this. It is naturally possible to provide a fifth portion at the root of the third surface 53 of the second tooth 33 that slopes away from the fourth surface 55 toward the tooth root. In this case, similarly to the embodiment, when the first surface 45 of the first tooth 32 is pressed against the fifth portion of the third surface 53 of the second tooth 33, the sleeve 31 and the fourth gear 29 are separated in the axial direction. Thrust is generated.

In the embodiment, the second surfaces 49, 60, 78 of the first teeth 32, 38, 74 and the fourth surfaces 55, 65, 80 of the second teeth 33, 39, 75, which mesh with each other, are the second surfaces 49, 60. This is a surface that generates a thrust force that separates the first teeth 32, 38, 74 and the second teeth 33, 39, 75 in the axial direction according to the torque in the direction of pressing the fourth surfaces 55, 65 (coasting torque). Although the case has been described, the case is not necessarily limited to this. Even if the second surfaces 49, 60, 78 and the fourth surfaces 55, 65, 80 are surfaces that do not generate thrust, when disengaging the sleeves 31, 37, 73, an external force is applied to the first teeth 32, 38, 74 and the second teeth 33, 39, 75 may be separated.

In the embodiment, due to the shape of the cam grooves 43, 84, 85 of the shift drum 42, when the first tooth 38 and the second tooth 39 of the dog clutch 76 for the low speed gear are disengaged, the first tooth for the high speed gear is disengaged. Although a case has been described in which the tooth 74 and the second tooth 75 are engaged with each other, the present invention is not limited to this. A sensor (for example, a position sensor of the sleeve 37) that detects the meshing between the first tooth 38 and the second tooth 39 of the dog clutch 76 is arranged, and the first tooth 74 and the second tooth 39 for the high-speed gear are connected based on the detection signal of the sensor. It may also be made to mesh with the teeth 75.

10, 70, 71 Transmission 11 Motor 12 Input shaft 13 First intermediate shaft 14 Second intermediate shaft 15 Output shaft 17 Friction clutch (synchronous mechanism)
22 Actuator 23 Power transmission device 29 Fourth gear (constantly meshing gear)
30, 36, 76 Dog clutch 31, 37 Sleeve 32, 38 1st tooth 33, 39 2nd tooth 35 6th gear (constantly meshing gear)
40 7th gear (constantly meshing gear)
41 Shift device 45, 59, 81 1st surface 46 1st part 49, 60 2nd surface 50 2nd part 53, 64 3rd surface 54 1st part 55, 65 4th surface 56 2nd part 72 Synchromesh (synchronization mechanism)
73 Sleeve 74 First tooth 75 Second tooth 77 First surface 78 Second surface 79 Third surface 80 Fourth surface

Claims (9)

an input shaft to which the rotation of the motor is input;
an output shaft arranged on a different axis from the input shaft;
a plurality of intermediate shafts arranged parallel to the output shaft on mutually different axes;
a plurality of power transmission paths that transmit the rotation of the input shaft to the output shaft at mutually different gear ratios through constantly meshing gears that are linked between each of the plurality of intermediate shafts and the output shaft;
Equipped with a synchronization mechanism that uses frictional force to reduce the difference between the rotational speed on the driving side and the rotational speed on the driven side,
The plurality of power transmission paths include a first path and a second path for adjacent gear stages,
The synchronizing mechanism is disposed on the first path, and the synchronizing mechanism is operated to switch between a state in which the first path transmits torque and a state in which the second path transmits torque. 2. When a frictional force is acting on the synchronizing mechanism in a state where there is relative rotation between the driving side and the driven side, the second path is brought into a state where torque is transmitted by upshifting. transmission. a sleeve that moves along an axis and is disposed on at least one of the plurality of power transmission paths;
a first tooth provided on the sleeve;
a second tooth that meshes with the first tooth and transmits torque between the driving side and the driven side,
The first tooth includes a first surface facing one circumferential direction and a second surface facing the other circumferential direction,
The second tooth has a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage, and a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage. a fourth surface facing at least a portion of the second surface,
The first surface and the third surface transmit torque in the direction of pressing the first surface and the third surface,
Claim 1: The second surface and the fourth surface generate a thrust force that disengages the first tooth and the second tooth in response to a torque in a direction that presses the second surface and the fourth surface. Or the transmission described in 2. comprising a dog clutch disposed in the power transmission path for the first gear, which connects and disconnects the power transmission path;
The dog clutch includes a sleeve that moves along an axis;
a first tooth provided on the sleeve;
a second tooth that meshes with the first tooth and transmits torque between the driving side and the driven side,
The first tooth includes a first surface facing one circumferential direction and a second surface facing the other circumferential direction,
The second tooth has a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage, and a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage. a fourth surface facing at least a portion of the second surface,
The first surface and the third surface include a first portion that transmits a torque in a direction of pressing the first surface and the second surface,
The second surface and the fourth surface include a second portion that transmits a torque in a direction to press the second surface and the fourth surface,
further comprising a shift device that moves the sleeve in an axial direction in which the first tooth and the second tooth engage,
The shift device moves the sleeve between a first axial position in which the first part transmits torque and a second axial position different from the first position in which torque is transmitted in the second part. The transmission according to any one of claims 1 to 3. comprising a dog clutch disposed in the power transmission path that connects and disconnects at least one of the plurality of power transmission paths;
The dog clutch includes a sleeve that moves along an axis;
a first tooth provided on the sleeve;
a second tooth that meshes with the first tooth and transmits torque between the driving side and the driven side,
The first tooth includes a first surface facing one circumferential direction and a second surface facing the other circumferential direction,
The second tooth has a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage, and a third surface that faces at least a portion of the first surface when the first tooth and the second tooth engage. a fourth surface facing at least a portion of the second surface,
The first surface and the third surface transmit torque in the direction of pressing the first surface and the third surface,
The second surface and the fourth surface generate a thrust that disengages the first tooth and the second tooth in response to a torque in a direction that presses the second surface and the fourth surface,
a shift in which the sleeve is moved in a first axial direction in which the first tooth and the second tooth mesh, and the sleeve is moved in a second axial direction in which the first tooth and the second tooth are disengaged; further equipped with equipment,
In the shift-up from a low gear to a high gear, when the first tooth and the second tooth of the dog clutch for the low gear are disengaged, the first tooth and the second tooth of the dog clutch for the low gear are disengaged. The transmission according to any one of claims 1 to 4, wherein the transmission meshes with the second tooth. 6. The transmission according to claim 3, wherein the first tooth is provided on one end surface of the sleeve in the axial direction. The transmission according to any one of claims 1 to 6, wherein the synchronization mechanism is a friction clutch. an actuator;
a power transmission device that transmits the output of the actuator to the friction clutch,
The transmission according to claim 7, wherein the power transmission efficiency of the power transmission device from the friction clutch to the actuator is negative. The synchronization mechanism is a synchromesh,
The synchromesh includes first teeth provided on a sleeve that moves along an axis;
7. The transmission according to claim 1, wherein second teeth that mesh with said first teeth are synchronized.

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