JP7413604B2 - parking mechanism - Google Patents

Description

The present invention relates to a parking mechanism for a vehicle.

As a parking mechanism for a vehicle in which a motor drives wheels, Patent Document 1 describes a pair of gears disposed on left and right mounting shafts of the wheels so as to be non-rotatable and movable in the axial direction, and a pair of gears arranged in the axial direction. A prior art is disclosed that includes a spring that moves apart, a mechanism that brings a pair of gears closer together in the axial direction when parking, and a pawl that engages the gears when parking. When the parking mechanism is activated, the pawl engages the gear, making it impossible for the wheel mounting shaft to rotate.

JP2020-94627A

The prior art requires additional parts such as gears and pawls to make up the parking mechanism. Furthermore, in the prior art, when the parking mechanism is activated when the vehicle is parked on an uphill or downhill slope, the gravity acting on the vehicle causes the wheels to rotate, and that force is applied to the gears and pawls. There is a problem in that the parking mechanism cannot be deactivated unless the parking mechanism is moved.

The present invention has been made to solve this problem, and an object of the present invention is to provide a vehicle parking mechanism that can be released with a small force and can eliminate the need for additional parts.

To achieve this objective, the present invention provides a plurality of power transmission paths that transmit the rotation of an input shaft into which the rotation of a motor is input to an output shaft at mutually different gear ratios, and a shift system that switches between the plurality of power transmission paths. A parking mechanism for a vehicle includes a transmission having a device and a transmission. One of the plurality of power transmission paths includes a friction clutch. The shift device has a parking mode in which one of the plurality of power transmission paths is established by connecting the friction clutch and another one of the plurality of power transmission paths is established.

According to the first aspect, the shift device switches between a plurality of power transmission paths that transmit the rotation of the input shaft, into which the rotation of the motor is input, to the output shaft at mutually different gear ratios. One of the plurality of power transmission paths includes a friction clutch. In the parking mode, the shift device connects the friction clutch to establish one of the plurality of power transmission paths, and establishes another one of the plurality of power transmission paths. In parking mode, the output shaft cannot rotate due to circulating torque, so parts other than the transmission for the parking mechanism can be eliminated. Furthermore, the operation of the parking mechanism can be canceled by disengaging the friction clutch.

According to the second aspect, the electric actuator operates the friction clutch in the first aspect. A power transmission device that transmits the output of an actuator to a friction clutch includes a holding mechanism that maintains the operation of the friction clutch when there is no output from the actuator. Therefore, even if the actuator stops operating, the friction clutch can remain connected.

According to the third aspect, in the second aspect, the actuator includes a drive gear that transmits torque to the power transmission device, and the power transmission device is provided with a first driven gear and a second driven gear that mesh with the drive gear. and a first element and a second element. The gear ratio between the drive gear and the first driven gear is different from the gear ratio between the drive gear and the second driven gear. In the power transmission device, the first element and the second element move relative to each other in the axial direction due to relative rotation between the first element and the second element, thereby converting the torque of the drive gear into thrust force. Therefore, power loss when the power transmission device converts torque into thrust force can be reduced.

According to the fourth aspect, in the power transmission device in the second aspect, a screw is disposed in the power transmission path from the friction clutch to the actuator. Since the power transmission efficiency is set using the friction of the screw, the structure of the holding mechanism can be simplified.

(a) is a skeleton diagram of the transmission in the first embodiment, and (b) is a schematic side view of the transmission. FIG. 2 is a diagram showing combinations of clutch connections; FIG. 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. FIG. 2 is a diagram showing combinations of clutch connections; FIG.

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 a parking mechanism that locks the wheels so that they do not rotate when the vehicle is parked.

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 transmits and interrupts power between the driving side and the driven side using frictional force. 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 first element 25 and a second element 26.

A cylindrical worm gear 24 is attached to the rotation shaft of the actuator 22. The torque of the worm gear 24 is transmitted to the first element 25, in which the first worm wheel 25a meshes with the worm gear 24, and to the second element 26, in which the second worm wheel 26a meshes with the worm gear 24. The first worm wheel 25a is provided on the outer periphery of the first element 25. The second worm wheel 26a is provided on the outer periphery of the second element 26. 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 the worm gear 24 and the first worm wheel 25a is different from the gear ratio between the worm gear 24 and the second worm wheel 26a. When the worm 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 worm 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 generate a thrust that presses the second element 26 against the pressing member 20. 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 worm gear 24 in the opposite direction, the frictional force generated on the clutch plate 19 becomes smaller.

The worm gear 24, the first worm wheel 25a, and the second worm wheel 26a constitute a holding mechanism in which the power transmission efficiency from the friction clutch 17 to the actuator 22 is negative. The holding mechanism holds the friction clutch 17 in operation when there is no output from the actuator 22. After the power transmission device 23 generates a thrust force to connect the friction clutch 17, the holding mechanism can prevent the worm gear 24 from rotating even if no current is applied to the actuator 22.

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. Torque is transmitted to the wheels by using the output shaft 15 as a wheel attachment shaft or by further arranging an output gear 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 includes a shift device 41 (see FIG. 4(a)). In the transmission 10, the friction clutch 17 and the dog clutches 30, 36 are connected to each other by a shift device 41, and the rotation of the input shaft 12 is transmitted 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.

FIG. 2 is a chart showing connection combinations of the friction clutch 17 and the dog clutches 30, 36. 1, R, 2, 3, N, and P in FIG. 2 indicate each mode of the shift device 41, 1: 1st speed, R: reverse, 2: 2nd speed, 3: 3rd speed, N: neutral, P: It is in parking mode. In FIG. 2, + indicates that the clutch is engaged, and - indicates that the clutch is disengaged (the same applies to FIG. 7).

When in first gear, the shift device 41 connects 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 shift device 41 transfers 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 speed, the shift device 41 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 speed, the shift device 41 engages the friction clutch 17 and disengages the dog clutches 30 and 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 between the friction clutch 17, the second gear 21, the sixth gear 35, and the seventh gear 40 in the third speed is referred to as the first path, and 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 speed is referred to as the first path, and the power transmission path between the first gear 16, the fifth gear 34, and the dog clutch 36 in the second speed is referred to as the first path. , the sixth gear 35 and the seventh gear 40 are referred to as a second path. When in neutral, shift device 41 disengages friction clutch 17 and dog clutches 30, 36.

In the parking mode, the shift device 41 connects the friction clutch 17 and the dog clutch 30, and disengages the dog clutch 36. This is the parking mechanism. When the dog clutch 30 is engaged, a first speed or reverse power transmission path is established, and when the friction clutch 17 is engaged, a third speed power transmission path is established. Since power transmission paths with different gear ratios are simultaneously established in the transmission 10, the output shaft 15 cannot rotate due to circulating torque, and the wheels linked to the output shaft 15 cannot rotate.

FIG. 3 is a schematic diagram of the dog clutch 30. FIG. 3 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. 3 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. 4(a) to 4(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. 4(a) to 4(c) show the states of forward first speed and reverse, and FIG. 4(d) to 4(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. 3), 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. In FIGS. 4(a) and 4(d), N: neutral, 1: 1st speed, R: reverse. Arrows F in FIGS. 4(b), 4(c), 4(e), and 4(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 43, and the shift rod 31a and sleeve 31 move in the axial direction accordingly. When the protrusion 44 is located at the "N" portion of the cam 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 43, the first tooth 32 meshes with the second tooth 33 (FIG. 4(a)).

As shown in FIG. 4(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. 3) 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. 4(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. 4(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. 4(f)).

When moving backward, the shift drum 42 rotates and the protrusion 44 is located at the "R" portion of the cam 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. 4(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. 4(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 gap between the cam 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.

5(a) and 5(b) are schematic diagrams of the dog clutch 36. 5(a) and 5(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. 5(a) and 5(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 operation of the transmission 10 will be explained. 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. 4(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. 5(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.

In the transmission 10, the friction clutch 17 is disposed on the first path where the gear position with the smallest gear ratio (3rd speed in this embodiment) is established, so the friction clutch 17 is used to connect the driving side and the driven side of the first path. You can synchronize the relative speed with. 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.

When the parking mode is selected after stopping the motor 11 and stopping the vehicle, the shift device 41 is activated to connect the friction clutch 17. When the vehicle is stopped with the transmission 10 in first gear or reverse, the output shaft 15 and the wheels can be locked by the circulating torque of the transmission 10 by simply connecting the friction clutch 17. Therefore, everything from selecting the parking mode to locking the wheels can be completed in a short time.

When the friction clutch 17 is engaged, torque is gradually transmitted from the driving side to the driven side, and the driven side is engaged without impact. Therefore, even if the parking mode is selected when the vehicle is not completely stopped, the rotation of the output shaft 15 and the wheels can be prevented from suddenly stopping, so that the wheels can be gently locked by the friction clutch 17.

When the parking mode is deselected, the friction clutch 17 is disengaged. Then, the second gear 21 idles on the input shaft 12, so the sixth gear 35 that meshes with the second gear 21, the seventh gear 40 that meshes with the sixth gear 35, and the fourth gear 29 that meshes with the seventh gear 40 It is no longer restricted by the second gear 21. Therefore, the second teeth 33 of the fourth gear 29 and the first teeth 32 of the sleeve 31 can be disengaged with a small force.

When the parking mode is deselected and the friction clutch 17 is disengaged, the first teeth 32 of the sleeve 31 are engaged with the second teeth 33 of the fourth gear 29, so that the fourth gear 29 and the seventh gear 40 are engaged. It is in a state where torque can be transmitted between. Therefore, when the motor 11 is rotated in the forward direction, the vehicle moves forward at first speed, and when the motor 11 is rotated in the reverse direction, the vehicle moves backward. Therefore, the process from canceling the parking mode selection to starting the vehicle can be completed in a short time.

A transmission 70 in a second embodiment will be described with reference to FIGS. 6(a) and 6(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. 6(a) is a skeleton diagram of the transmission 70 in the second embodiment. FIG. 6(b) is a schematic side view of the transmission 70.

In the transmission 70 , a power transmission device 71 transmits the output of the actuator 22 to the friction clutch 17 . The power transmission device 71 includes a first element 75 and a second element 77.

A drive gear 24a is attached to the rotation shaft of the actuator 22. The drive gear 24a consists of two gears having slightly different numbers of teeth. The torque of the drive gear 24a is transmitted to a first element 75 where the first driven gear 72 meshes with the drive gear 24a, and a second element 77 where the second driven gear 73 meshes with the drive gear 24a. The first driven gear 72 and the first element 75 are connected by an inner cylinder 74 that extends in the axial direction. The second driven gear 73 and the second element 77 are connected by an outer cylinder 76 that extends in the axial direction. The outer cylinder 76 is located outside the inner cylinder 74 in the radial direction. Screws 79 (retention mechanism) that engage with each other are provided on the outer peripheral surface of the inner cylinder 74 and the inner peripheral surface of the outer cylinder 76. The center axis of the screw 79 is arranged coaxially with the input shaft 12 .

The first driven gear 72, the second driven gear 73, the inner cylinder 74, the first element 75, the outer cylinder 76, and the second element 77 are supported by the input shaft 12 so as to be relatively rotatable. The gear ratio between the drive gear 24a and the first driven gear 72 is different from the gear ratio between the drive gear 24 and the second driven gear 73. When the drive gear 24a transmits torque to the first element 75 and the second element 77 via the first driven gear 72 and the second driven gear 73, the first element 75 and the second element 77 rotate slightly relative to each other. The position of the second element 77 in the axial direction with respect to the input shaft 12 is fixed.

At least one rolling element 78 is disposed between the cam surface provided on the first element 75 and the cam surface provided on the second element 77. Examples of the rolling elements 78 include balls and rollers. The rolling element 78 rolls along the slope between the two cam surfaces due to friction. A return spring (not shown) of the friction clutch 17 presses the first element 75 against the rolling element 78 via the pressing member 20 .

When the actuator 22 is actuated to rotate the drive gear 24a in the forward direction and the first element 75 and the second element 77 are rotated relative to each other, the rolling elements 78 roll on the cam surface and press the first element 75 against the pressing member 20. Thrust force is generated. When the first element 75 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 24a in the opposite direction, the frictional force generated on the clutch plate 19 becomes smaller.

Due to the friction of the screw 79, the power transmission efficiency from the friction clutch 17 to the actuator 22 is set to be negative. Since the friction clutch 17 can remain connected even when the actuator 22 stops operating, the power consumption of the actuator 22 can be reduced.

FIG. 7 is a chart showing connection combinations of the friction clutch 17 and the dog clutches 30, 36. 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 . 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.

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.

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. 4(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.

When in neutral, the transmission 70 disengages the friction clutch 17 and the dog clutches 30, 36. In the parking mode, the transmission 70 connects the friction clutch 17 and the dog clutch 30, and disengages the dog clutch 36. When the dog clutch 30 is engaged, a first speed or reverse power transmission path is established, and when the friction clutch 17 is connected, a second speed power transmission path is established. Since power transmission paths with different gear ratios are simultaneously established in the transmission 70, the output shaft 15 cannot rotate due to circulating torque, and the wheels linked to the output shaft 15 cannot rotate.

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 transmitted to the output shaft 15 by the first gear 16, the second gear 21, the third gear 28, the fourth gear 29, the fifth gear 34, the sixth gear 35, and the seventh gear 40. Although the case has been described, the case is not necessarily limited to this. It is of course possible to employ transmission elements other than gears in the transmissions 10, 70. Examples of transmission elements other than gears include chains, sprockets, belts, and pulleys.

In the embodiment, the transmissions 10 and 70 in which the input shaft 12 and the output shaft 15 are arranged on different axes have been described, but the invention is not necessarily limited to this. Even in a transmission in which the input shaft 12 and the output shaft 15 are arranged coaxially, if two power transmission paths with different gear ratios are established simultaneously by connecting a friction clutch, it can be used as a parking mechanism.

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 technique 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 case has been described in which the dog clutch 30 and the friction clutch 17 are connected in the parking mode to lock the output shaft 15, but the invention is not necessarily limited to this. Naturally, it is possible to lock the output shaft 15 by connecting the dog clutch 36 and the friction clutch 17 in the parking mode. However, if the vehicle is stopped in first gear or reverse, the dog clutch 30 is engaged, so the output shaft 15 and wheels can be locked simply by engaging the friction clutch 17. This is preferable because the process from selecting the parking mode to locking the wheels can be completed in a short time. Furthermore, when the friction clutch 17 is disengaged, the vehicle can move forward or backward in first gear. This is preferable because the process from canceling the selection of the parking mode to starting the vehicle can be completed in a short time.

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

In the second embodiment, in the power transmission device 71, an inner cylinder 74 connects the first driven gear 72 and the first element 75, an outer cylinder 76 connects the second driven gear 73 and the second element 77, Although a case has been described in which a screw 79 is provided to fasten the space between the two, the present invention is not limited to this. Instead of the screw 79, the specifications and surface roughness of the tooth surfaces of the drive gear 24, first driven gear 25a, and second driven gear 26a are adjusted so that the power transmission efficiency from the friction clutch 17 to the actuator 22 becomes negative. Of course, it is possible to set this.

10,70 Transmission (parking mechanism)
11 Motor 12 Input shaft 15 Output shaft 17 Friction clutch 22 Actuator 23, 71 Power transmission device 24 Worm gear (part of holding mechanism)
24a Drive gear 25a First worm wheel (part of holding mechanism)
26a Second worm wheel (part of the holding mechanism)
41 Shift device 72 First driven gear 73 Second driven gear 75 First element 77 Second element 79 Screw (holding mechanism)

Claims (4)

a plurality of power transmission paths that transmit the rotation of the input shaft, into which the rotation of the motor is input, to the output shaft at mutually different gear ratios;
A parking mechanism for a vehicle comprising a transmission having a shift device that switches the plurality of power transmission paths,
One of the plurality of power transmission paths includes a friction clutch,
The shift device is a parking mechanism including a parking mode in which the friction clutch is connected to establish one of the plurality of power transmission paths and to establish another one of the plurality of power transmission paths. an electric actuator that operates the friction clutch;
a power transmission device that transmits the output of the actuator to the friction clutch,
The parking mechanism according to claim 1, wherein the power transmission device includes a holding mechanism that holds the friction clutch in operation when there is no output from the actuator. The actuator includes a drive gear that transmits torque to the power transmission device,
The power transmission device includes a first element and a second element each provided with a first driven gear and a second driven gear that mesh with the drive gear,
Relative rotation between the first element and the second element causes the first element and the second element to move relative to each other in the axial direction, converting the torque of the drive gear into a thrust force,
3. The parking mechanism according to claim 2, wherein a gear ratio between the drive gear and the first driven gear is different from a gear ratio between the drive gear and the second driven gear. 3. The parking mechanism according to claim 2, wherein the power transmission device includes a screw disposed in a power transmission path from the friction clutch to the actuator.

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