JP2024058786A - Meshing mechanism - Google Patents

Abstract

[Problem] To provide a meshing mechanism that can eliminate edge contact of dog teeth in response to a shift operation performed by an operator at any timing. [Solution] The meshing mechanism is characterized by comprising one rotating member 33, 35, 37 that can be shifted in the axial direction, the other rotating member 9, 11, 17, 19, 23, 27 for transmitting torque between the one rotating member, dog teeth 33a, 33b, ... provided on each of the one and other rotating members and meshing with each other in the rotational direction to transmit the torque, a shift mechanism 39 that shifts one of the rotating bodies by a shift operation to mesh with the dog teeth, a waiting mechanism 41 provided in the shift mechanism to wait for the shift movement of one of the rotating bodies by the shift operation, a pair of sensors that separately detect the rotational positions of the dog teeth of the one and other rotating members, and a control unit 45 that calculates the meshing timing for the dog teeth to mesh without hitting each other based on the rotational positions detected by the pair of sensors and releases the waiting mechanism from standby. [Selected Figure] Figure 1

Description

The present invention relates to a meshing mechanism for saddle-type vehicles, etc.

A conventional meshing mechanism is described in Patent Document 1 and is applied to a saddle-type vehicle.

This meshing mechanism sets the start timing of processing based on the rotation angle of at least one of the input shaft and the output shaft detected by the rotation angle detector, and performs control separately for cases where dog contact occurs and cases where dog contact does not occur. This control is designed to start at least the processing to increase or decrease the output of the power source so that the timing to start increasing or decreasing the output of the power source based on the timing of detection of operation by the shift pedal operation detector is different.

This allows the process to be started at a time that cancels shock, regardless of dog contact, for example. As a result, it is said that inertia phase shock can be reduced even in a transmission where the gear shift is performed by the driver's foot force.

However, with this type of meshing mechanism, there is a problem in that it is not possible to prevent dog tooth contact when the operator operates the shift pedal at any time. In other words, when dog tooth contact occurs, the power reduction process starts at a later timing than when dog tooth contact does not occur. Therefore, although the effects of dog tooth contact can be suppressed, the problem of dog tooth edge contact remains.

JP 2019-99073 A

The problem to be solved is that although it is possible to reduce the effect of dog contact on shift operations performed at any time by the operator, it still leads to contact with the edges of the dog teeth.

The meshing mechanism of the present invention is characterized by comprising one rotating member that can be shifted in the axial direction, the other rotating member for transmitting torque between the one rotating member and the other rotating member, dog teeth provided on each of the one and other rotating members that mesh with each other in the rotational direction to transmit the torque, a shift mechanism that shifts the one rotating body by a shift operation to mesh with the dog teeth, a waiting mechanism provided in the shift mechanism that waits for the shift movement by the shift operation, a pair of sensors that separately detect the rotational positions of the dog teeth of the one and other rotating members, and a control unit that calculates the meshing timing for the dog teeth to mesh without hitting each other from the rotational positions detected by the pair of sensors and releases the waiting mechanism from standby.

The meshing mechanism of the present invention, configured as described above, calculates the meshing timing for meshing without the dog teeth hitting each other from the rotational positions detected by the pair of sensors and releases the waiting mechanism from standby, eliminating the dog teeth hitting the edges when the operator performs a shift operation at any timing.

1 is a schematic cross-sectional view of a main portion of a transmission having a meshing mechanism using dog teeth according to a first embodiment; FIG. 2 is a schematic diagram of a wait mechanism for use in the transmission of FIG. 1; 2A is a cross-sectional view of a quick shift sensor having an elastic body shared by the waiting mechanism used in the transmission of FIG. 1, in which FIG. 2A is an OFF state, FIG. 2B is a cross-sectional view of a quick shift sensor during upshifting, and FIG. 2C is a cross-sectional view of a quick shift sensor during downshifting. 2 is a time chart showing a shift-up time including a waiting mechanism of the transmission shown in FIG. 1 . FIG. 11 is a schematic cross-sectional view showing another example of a transmission having a meshing mechanism using dog teeth according to the second embodiment. FIG. 6 is a cross-sectional view of a main portion showing shallow meshing of dog teeth used in the transmission of FIG. 5 . FIG. 11 is a development view of a main portion showing a relationship between a shift pin and a shift drum according to a comparative example. FIG. 6 is a cross-sectional view of a main portion showing an example of a failure in meshing of dog teeth used in the transmission of FIG. 5 . FIG. 6 is a development view of a shift drum showing the positions of shift pins used in the transmission of FIG. FIG. 10 is an exploded view of a main part of the shift drum of FIG. FIG. 4 is an explanatory diagram of a check mechanism of the shift drum. FIG. 11 is a diagram showing a relationship between an engagement state of dog teeth and a position of a shift pin with respect to a shift drum in a comparative example. FIG. 10 is a diagram showing the relationship between the meshing state of the dog teeth and the position of the shift pin with respect to the shift drum in the second embodiment.

The goal of eliminating the dog tooth edge contact when the operator performs a shift operation at any timing was achieved as follows:

The device is realized in a form including one rotating member that can be shifted in the axial direction, the other rotating member for transmitting torque between the one rotating member, dog teeth provided on each of the one and the other rotating members that mesh in the rotational direction to transmit the torque, a shift mechanism that shifts one of the rotating bodies by a shift operation to mesh the dog teeth, a waiting mechanism provided in the shift mechanism that waits for the shift movement of the one rotating body by the shift operation, a pair of sensors that separately detect the rotational positions of the dog teeth of the one and the other rotating members, and a control unit that calculates the meshing timing for the dog teeth to mesh without hitting each other based on the rotational positions detected by the pair of sensors and releases the waiting mechanism from standby.

There are no limitations on the types of vehicles to which the meshing mechanism can be applied, so long as it meshes the dog teeth in response to an operator's shift operation. For example, the mechanism can be applied to four-wheeled vehicles, two-wheeled vehicles, buggies, snowmobiles, saddle-type vehicles, industrial machinery, agricultural machinery, ships, small airplanes, etc.

One of the rotating members is realized by a clutch ring, but it may also be realized by a gear that doubles as a clutch ring.

The dog teeth can be general dog teeth, dog teeth for seamless shifting, etc., without any particular limitations.

The shift mechanism only needs to be able to shift one of the rotating bodies by shifting to engage the dog teeth, and can be realized without limitation by shifting using a shift pedal, a shift lever, etc.

The waiting mechanism only needs to be able to wait for one of the rotating bodies to shift due to a shift operation, and can be realized by including an elastic body, a solenoid, etc.

The waiting mechanism includes a transmission unit, a shift drive arm, and a release mechanism. The transmission unit transmits the operating force of the shift mechanism via an elastic body, the shift drive arm operates with the operating force via the transmission unit, and the release mechanism releasably stops the operation of the shift drive arm, accumulates the operating force in the elastic body, and releases it under the control of the control unit.

The operation of the shift drive arm is stopped by a solenoid, but the solenoid can also be replaced with an electric motor. It can also be realized by configuring the transmission unit electrically, electrically detecting the operation of the shift mechanism, and operating the shift drive arm by a solenoid or electric motor at the calculated meshing timing.

The control unit releases the waiting mechanism from standby while reducing the rotational difference between one and the other rotating members or the input torque. This can also be achieved by reducing both the rotational difference and the input torque.

In the case of an internal combustion engine, reducing the rotational difference or input torque is achieved by cutting the ignition, but it is sufficient if the rotational difference or input torque between one and the other rotating members can be reduced. Reducing the rotational difference or input torque can also be achieved by changing the ignition timing, cutting the fuel, braking the input shaft, or disengaging the starting clutch. If the power source is an electric motor, it can also be achieved by reducing the current, braking the input shaft (regeneration), etc.

One rotating member is a clutch ring provided on the input shaft or output shaft, and the other rotating member is one of the constant-mesh variable speed gears provided on the input shaft or output shaft. When the dog teeth of the clutch ring mesh with the dog teeth of one of the variable speed gears, torque is transmitted between the input and output shafts via the constant-mesh variable speed gear.

The sensor is realized by including an input shaft sensor that detects the rotation pulse of the input shaft and an output shaft sensor that detects the rotation pulse of the output shaft.

[Transmission Overview]
FIG. 1 is a schematic cross-sectional view of a main portion of a transmission having a meshing mechanism using dog teeth.

The transmission 1 in FIG. 1 is used, for example, in a saddle-type vehicle. As shown in FIG. 1, the transmission 1 has an input shaft 3 and an output shaft 5. The input shaft 3 and the output shaft 5 are rotatably supported in a transmission case (not shown) by bearings or the like.

The input shaft 3 and the output shaft 5 support first-speed gears 7 and 9, second-speed gears 11 and 13, third-speed gears 15 and 17, fourth-speed gears 19 and 21, fifth-speed gears 23 and 25, and sixth-speed gears 27 and 29 as multi-speed gears, which are constantly meshed with each other.

The first-speed gear 7 and third-speed gear 15 of the input shaft 3 are supported so as to rotate integrally with the input shaft 3, and the second-speed gear 13, fourth-speed gear 21, fifth-speed gear 25, and sixth-speed gear 29 of the output shaft 5 are supported so as to rotate integrally with the output shaft 3.

The second-speed gear 11, fourth-speed gear 19, fifth-speed gear 23, and sixth-speed gear 27 of the input shaft 3 are supported for relative rotation on the input shaft 3, and the first-speed gear 9 and third-speed gear 17 of the output shaft 5 are supported for relative rotation on the output shaft 5.

The transmission 1 is equipped with a meshing mechanism 31 for shifting gears. The meshing mechanism 31 is equipped with one rotating member 33, 35, 37, the other rotating member 9, 11, 17, 19, 23, 27, dog teeth 33a, 33b, 35a, 35b, 37a, 37b, 9a, 11a, 17a, 19a, 23a, 27a, a shift mechanism 39, a waiting mechanism 41, a pair of input shaft sensors 43a, 43b, and a control unit 45.

The rotating members 33, 35, and 37 on one side are made up of a first, second, and third clutch ring. The first, second, and third clutch rings 33, 35, and 37 are spline-fitted to the output shaft 5, allowing them to be shifted in the axial direction.

The other rotating members 9, 11, 17, 19, 23, 27 are the first gear 9 and third gear 17 on the output shaft 5 for transmitting torque to the first clutch ring 33, the second gear 11 and fifth gear 23 on the input shaft 3 for transmitting torque to the second clutch ring 35, and the fourth gear 19 and sixth gear 27 on the input shaft 3 for transmitting torque to the third clutch ring 37.

Dog teeth 33a and 33b are provided on the first clutch ring 33, and dog teeth 9a and dog teeth 17a are provided separately on the first-speed gear 9 and the third-speed gear 17, respectively. Dog teeth 33a and dog teeth 9a or dog teeth 33b and dog teeth 17a mesh in the rotational direction to transmit torque from the first-speed gear 9 or the third-speed gear 17 to the output shaft 5.

Dog teeth 35a and 35b are provided on the second clutch ring 35, and dog teeth 11a and 23a are provided separately for the second-speed gear 11 and the fifth-speed gear 23. Dog teeth 35a and 11a or dog teeth 35b and dog teeth 23a mesh in the rotational direction to transmit torque from the input shaft 3 to the second-speed gear 11 or the fifth-speed gear 23.

Dog teeth 37a and 37b are provided on the third clutch ring 37, and dog teeth 19a and 27a are provided separately for the fourth-speed gear 19 and the sixth-speed gear 27, respectively. Dog teeth 37a and 19a or dog teeth 37b and dog teeth 27a mesh in the rotational direction to transmit torque from the input shaft 3 to the fourth-speed gear 19 or the sixth-speed gear 27.

The shapes of the dog teeth 33a, 33b, 35a, 35b, 37a, 37b, 9a, 11a, 17a, 19a, 23a, and 27a are not particularly limited to normal dog teeth, seamless shift dog teeth, etc., and various shapes can be adopted. An example will be described using seamless shift.

The shift mechanism 39 shifts one of the first, second and third clutch rings 33, 35 and 37 in response to a shift operation. The shift mechanism 39 includes a shift drum (not shown), a shift rod and a shift fork that are linked to the shift operation of the shift pedal described below. The rotation of the shift drum is transmitted to the respective shift forks of the first, second and third clutch rings 33, 35 and 37 via a shift cam and a shift rod, and one of the first, second and third clutch rings 33, 35 and 37 is shifted in response to the shift operation.

The first clutch ring 33 is shifted to engage the first-speed dog clutch of dog teeth 33a and dog teeth 9a or the third-speed dog clutch of dog teeth 33b and dog teeth 17a. The second clutch ring 35 is shifted to engage the second-speed dog clutch of dog teeth 35a and dog teeth 11a or the fifth-speed dog clutch of dog teeth 35b and dog teeth 23a. The third clutch ring 37 is shifted to engage the fourth-speed dog clutch of dog teeth 37a and dog teeth 19a or the sixth-speed dog clutch of dog teeth 27a and dog teeth 37b.

The waiting mechanism 41 is provided in the shift mechanism 39 and waits for the first clutch ring 33, the second clutch ring 35, or the third clutch ring 37 to shift due to a shift operation.

The pair of sensors 43a and 43b are an input sensor and an output shaft sensor that separately detect the rotational positions of the dog teeth of one and the other rotating members. The input shaft sensor 43a is attached to detect the detection gear 47 of the input shaft 3, and the output shaft sensor 43b is attached to detect the detection gear 49 of the output shaft 5. The detection pulses of the input shaft sensor 43a and the output shaft sensor 43b are input to the control unit 45.

The input shaft sensor 43a detects the rotational position of the input shaft 3. Based on this detection, the rotational positions of the dog teeth 35a, 35b, 37a, 37b of the second clutch ring 35 and the third clutch ring 37, and the dog teeth 9a, 17a of the first and third gears 9, 17 are detected.

The output shaft sensor 43b detects the rotational position of the output shaft 5. Based on this detection, the rotational positions of the dog teeth 33a, 33b of the first clutch ring 33 and the dog teeth 11a, 19a, 23a, 27a of the second, fourth, fifth, and sixth gears 11, 19, 23, 27 are detected.

The control unit 45 calculates the meshing timing for each gear stage's dog teeth 33a, 9a, dog teeth 35a, 11a, dog teeth 33b, 17a, dog teeth 37a, 19a, dog teeth 35ba, 23a, dog teeth 37b, 27a to mesh without abutting each other during gear shifting, and controls the waiting mechanism 41 to release standby.

The control unit 45 is configured with an MPU, ROM, RAM, etc. The control unit 45 calculates the meshing timing from the input pulse signal, the relative rotational positions of the input and output shafts 3 and 5 when the dog teeth 35a, 11a, dog teeth 33b, 17a, dog teeth 37a, 19a, dog teeth 35ba, 23a, dog teeth 37b, 27a of each shift-up gear mesh, information on which gear the dog teeth 33a, 9a... are meshing with, and the count of the rotational positions of the dog teeth 33a, 9a... of each gear.

(Shift mechanism and waiting mechanism)
FIG. 2 is a diagram showing the shift pedal and other components of the shift mechanism 39. As shown in FIG.

The shift pedal 51 in FIG. 2 is a type that is operated by the foot of a driver of a saddle-type vehicle, and is rotatably supported on the vehicle body by a support shaft 53. The shift pedal 51 includes an operating part 55 that is operated by the foot, and a rod connecting part 56.

One end of an interlocking rod 58 is rotatably connected to the rod connecting portion 56 as a transmission portion, and an abutment plate 57 is fixed to the other end of the interlocking rod 58. The interlocking rod 58 has an elastic body 59 with an expandable structure, and is equipped with a shift sensor (not shown). The detection signal of the shift sensor is input to the control portion 45. Note that although the elastic body 59 is shown in FIG. 2, it is arranged inside the case as a quick shift sensor, as described later. The elastic body 59 of the waiting mechanism 41 shares the elastic body of the quick shift sensor. The operation of the waiting mechanism 41 and the quick shift sensor will be described later together with the operation of the shift pedal 51.

An arm connector 60 is fixed to the abutment plate 57 so as to sandwich the abutment plate 57 together with the interlocking rod 58. The arm connector 60 is connected to one end of a shift drive arm 61 so as to be capable of relative rotation. The other end of the shift drive arm 61 has an axis 61a coaxially connected to a shift shaft (not shown) (not shown). When the shift drum (not shown in this embodiment) rotates via a shift ratchet (not shown) due to the rotation of the shift shaft, one of the first, second and third clutch rings 33, 35 and 37 is shifted as described above.

A stopper 63 is disposed on the abutment plate 57 in a position aligned with the arm connecting portion 60. The stopper 63 is supported on the vehicle body side so as to be freely rotatable. A release rod 65a of a release mechanism 65 is rotatably connected to a connecting protrusion 63a around the rotation axis of the stopper 63. The rotation of the stopper 63 is determined by the release mechanism 65, and a roller portion 63b at the tip abuts against the abutment plate 57. The release mechanism 65 is composed of a solenoid or the like. The release mechanism 65 is connected to the control unit 45 and is electrically controlled.

The waiting mechanism 41 is composed of a release mechanism 65, a stopper 63, a contact plate 57, and a shared elastic body 59, and temporarily stores the operating force of the shift pedal 51 in the elastic body 59. The release mechanism 65 operates under the control of the control unit 45, and the waiting mechanism 41 is released.

Figure 3(A) is a cross-sectional view of the quick shift sensor when it is OFF. Figure 3(B) is a cross-sectional view of the quick shift sensor when it is upshifting. Figure 3(C) is a cross-sectional view of the quick shift sensor when it is downshifting.

As shown in FIG. 3, the interlocking rod 58 is divided into a first rod 58a on the pedal side and a second rod 58b on the contact plate side. A quick shift sensor 67 equipped with an elastic body 59 is interposed between the first and second rods 58a and 58b. A case 67a is fixed to the first rod 58a, and a pair of flanges 67b and 67c arranged inside the case 67a are provided on the second rod 58b. Movable contact plates 67d and 67e are arranged between the flanges 67b and 67c, and an elastic body 59 is interposed between the contact plates 67d and 67e. A switch 67f is attached to one of the contact plates 67d, and the contact of the switch 67f faces the other contact plate 67e. The contact plates 67d and 67e are electrically connected to the control unit 45 side, so that the detection signal of the switch 67f is input to the control unit 45.

(Shift up operation)
In FIG. 2, when the operating portion 53 of the shift pedal 51 is operated with the foot to shift up in the lifting direction (arrow direction), the rod connecting portion 56 presses the interlocking rod 58 against the abutment plate 57 in the axial direction.

When the interlocking rod 58 is pressed, the case 67a of the first rod 58a presses one of the contact plates 67d as shown in FIG. 3. This pressure causes the contact plate 67d to move relative to the second rod 58b from the state shown in FIG. 3(A) to that shown in FIG. 3(B), compressing the elastic body 59 and accumulating operating force. The switch 67f comes into contact with the other contact plate 67e. This contact turns the switch 67f ON, detecting the shift operation and inputting a detection signal to the control unit 45.

If the meshing timing calculated by the control unit 45 is not appropriate, the waiting mechanism 41 will not be released in the state shown in FIG. 2, but if it is appropriate, the release mechanism 65 of the waiting mechanism 41 will operate under the control of the control unit 45. This operation pulls the connecting protrusion 63a of the stopper 63, causing the stopper 63 to rotate and the roller portion 63b to instantly detach from the abutment plate 57. This release releases the positioning of the abutment plate 57, and when the elastic body 59 is released and the interlocking rod 58 extends, the abutment plate 57 will instantly move.

This movement pushes one end of the shift drive arm 61 through the arm connector 60, causing the shift drive arm 61 to rotate around the shaft 61a. The rotation of the shaft 61a causes the shift drum to rotate through the shift shaft and the shift ratchet. This rotation shifts one of the first, second and third clutch rings 33, 35 and 37 according to the upshift operation as described above, and when upshifting, the dog teeth 33a, 9a (1st gear), dog teeth 35a, 11a (2nd gear), dog teeth 33b, 17a (3rd gear), dog teeth 37a, 19a (4th gear), dog teeth 35ba, 23a (5th gear) and dog teeth 37b, 27a (6th gear) of each of the 1st to 6th gears can be engaged with the appropriate engagement timing.

(Shift down operation)
When the operating portion 53 of the shift pedal 51 is depressed by the foot to shift down (in the direction opposite to the arrow), the rod connecting portion 56 operates in a direction pulling the interlocking rod 58 axially relative to the contact plate 57 .

When the interlocking rod 58 is pulled, the first rod 58a pulls the case 67a in a direction away from the other contact plate 67e as shown in Figure 3. This pulling action moves the other contact plate 67e away from the flange 67c from the state shown in Figure 3(A) to the state shown in Figure 3(C), compressing the elastic body 59 and causing the other contact plate 67e to come into contact with the switch 67f. This contact turns the switch 67f ON, detecting the shift operation and inputting a detection signal to the control unit 45.

When shifting down, the waiting mechanism 41 does not work, and the control unit 45 memorizes the gear stage based on the signal from the switch 67f, and can engage the dog teeth 33a, 9a (1st gear), dog teeth 35a, 11a (2nd gear), dog teeth 33b, 17a (3rd gear), dog teeth 37a, 19a (4th gear), and dog teeth 35ba, 23a (5th gear) of each of the 1st to 5th gears.

(Engagement timing)
The timing of meshing is detected based on phase detection of the input shaft and the output shaft by a pulse sensor. The input shaft 3 is mechanically connected to the dog teeth on the input side of each gear by gear meshing or by a clutch ring. For example, in the first and third gears, the dog teeth 9a and 17a are connected to the input shaft 3 by meshing of the first gears 7 and 9 and meshing of the third gears 15 and 17. In the second and fifth gears, the dog teeth 35a and 35b are connected to the input shaft 3 by a second clutch ring 35. In the fourth and sixth gears, the dog teeth 37a and 37b are connected to the input shaft 3 by a third clutch ring 37.

Similarly, the output shaft 5 is mechanically connected to the dog teeth on the output side of each gear by gear meshing or by a clutch ring. For example, in first and third gears, dog teeth 33a, 33b are connected to the output shaft 5 by a first clutch ring 33. In second and fifth gears, dog teeth 11a, 23a are connected to the output shaft 5 by meshing of second gears 11, 13 and meshing of fifth gears 23, 25. In fourth and sixth gears, dog teeth 17a, 27a are connected to the output shaft 5 by meshing of fourth gears 19, 21 and meshing of sixth gears 27, 29.

Therefore, by counting the detection pulses of the input shaft 3 and the output shaft 5, the rotational angles of the dog teeth 33a, 9a (1st gear), dog teeth 35a, 11a (2nd gear), ... for each gear can be calculated.

When the dog teeth 33a, 9a (1st gear), dog teeth 35a, 11a (2nd gear), ... of the dog clutch of any one of the gears are engaged, the gears and dog teeth of the other gears rotate regularly at a constant ratio. As a result, the timing of engagement for the dog teeth of each gear to engage without hitting each other appears regularly.

When a shift is made to any gear and drive torque is applied, there is no play in the transmission of driving force between the input and output shafts 3 and 5. At this time, the control unit 45 stores that the relative angle between the dog teeth on the input side and the dog teeth on the output side of the dog clutch for the current gear is 0°. This operation is called calibration. Calibration is performed every time the dog clutch for each gear is engaged with drive torque applied.

Here, the calibrated gear is assumed to be third gear, for example.

When upshifting from the calibrated state to fourth gear, a relative angle is generated between the dog teeth 17a on the input side of third gear and the dog teeth 33b on the output side from the moment the dog clutch of fourth gear engages. This change in angle is detected to determine whether third gear has disengaged. From the moment the engagement is disengaged, the detection pulse starts counting the rotation angle of the dog teeth 17a, 33b of third gear.

The pulse count is performed independently for the input dog teeth and output dog teeth of each gear. For example, for a six-speed transmission, 12 pulse counters are set up on the control software of the control unit 45.

When upshifting from 3rd to 4th gear, the relative angle is calculated from the number of pulses in the pulse counter to determine the meshing timing of dog teeth 19a and 37a.

(Determining the dog tooth rotation angle)
In the initial calibration, all stages are meshed one by one. The control unit 45 stores the relationship between the detection pulses of the input shaft sensors 43a, 43b of the input and output shafts 3, 5 as the meshed position. The control unit 45 stores the phase at which the dog teeth meshed, and stores the number of rotations after the dog teeth come out, to calculate the meshing timing at which the dog teeth will mesh again.

(Dog phase of input/output axis)
The angle at which the dog teeth realign from the time they disengage is calculated.

Gear ratio x (360/number of teeth) = rotation angle at which the next dog tooth has the same angle Example 1: 1st gear When the gear ratio is 15/36 and the number of dog teeth is 5 → the rotation angle of the 1st gear 9 on the output shaft 5 is calculated from the detection pulse of the input shaft 3.
(36/15) x (360/5) = 172.8 degrees

The input shaft 3 rotates at 172.8° and the dog teeth 9a rotate at the same angle.

Example 2: 2nd gear, gear ratio 19/39, number of dog teeth 5 → The rotation angle of the 2nd gear 11 on the input shaft 3 is calculated from the detection pulse of the output shaft 5.
(19/39) x (360/5) = 35.07692 degrees

The input shaft 3 rotates at 147.7895° and the dog teeth 11a rotate at the same angle.

The counter memory of the control unit 45 is reset to 0° for each divisible rotation angle to prevent overflow.

Divisible rotation angle in Example 1 = Least common multiple of (36, 15) → 180 rotations Divisible rotation angle in Example 2 = Least common multiple of (39, 19) → 741 rotations Reset is performed at this angle.

(N → 1st gear) Shift (1) Detection of rotation angle of 1st gear 9 Since the 1st gear 9 rotates in mesh with the 1st gear 7 of the input shaft 3, it has a rotation angle of 1st gear reduction ratio, and the detection pulses of the input shaft sensor 43a on the input shaft 3 side are counted.
(Number of input shaft pulses x pulse interval angle x 1st gear reduction ratio) = rotation angle of 1st gear 9

(2) Detection of Rotation Angle of First Clutch Ring Since the first clutch ring 33 rotates integrally with the output shaft 5, the detection pulses of the output shaft sensor 43b on the output shaft 5 side are counted.
(Number of output shaft side pulses × angle of pulse interval) = rotation angle of first clutch ring 33

(3) Calculation of meshing timing The time from the start of shifting until the axial distance at which meshing is possible is stored in the control unit 45. The relative angle of the first speed gear 9 and the first clutch ring 33 is calculated, and the shift start timing is calculated by counting backwards from the time at which the dog teeth 33a of the first clutch ring 33 reach the axial distance at which meshing is possible with the dog teeth 9a of the first speed gear 9.

(1st gear → 2nd gear) Shift From a state in which the 1st gear dog clutch (dog teeth 9a, 33a) of the 1st gear gear 9 and the first clutch ring 33 are engaged and driven, the 2nd gear dog clutch (dog teeth 35a, 11a) of the second clutch ring 35 and the 2nd gear gear 11 is engaged. The 1st gear dog clutch of the 1st gear gear 9 and the first clutch ring 33 is disengaged.

(4) Detection of Rotation Angle of Second-Speed Gear 11 The second-speed gear 11 rotates in mesh with the second-speed gear 13 of the output shaft 5, resulting in a rotation angle of the second-speed reduction ratio, and detection pulses from the output shaft sensor 43b on the output shaft 5 side are counted.
(Number of pulses on the output shaft side x Angle of pulse interval x Second speed reduction ratio) = Rotation angle of second speed gear 11

(5) Detection of Rotation Angle of Second Clutch Ring Since the second clutch ring 35 rotates integrally with the input shaft 3, the detection pulses of the input shaft sensor 43a on the input shaft 3 side are counted.
(Number of input shaft side pulses × angle of pulse interval) = rotation angle of second clutch ring 35

(6) Calculation of meshing timing The time from the start of shifting until the axial distance at which meshing is possible is stored in the control unit 45. The relative accuracy of the second speed gear 11 and the second clutch ring 35 is calculated, and the shift start timing is calculated by counting backwards from the time at which the dog teeth 35a of the second clutch ring 35 reach the axial distance at which meshing is possible with the dog teeth 11a of the second speed gear 11.

The rotational phase is controlled by cutting off ignition at the timing of meshing in any gear. However, ignition cut can be omitted.

(Angular velocity detection)
In the above explanation, the change in angle can be calculated by calculating the angular velocity from the time between the immediately preceding detection pulses, and based on this angular velocity information, it can be estimated how many milliseconds the angle will reach.

(Time chart)
Fig. 4 is a time chart showing the relationship between the waiting mechanism, the shift drum, and the meshing timing of the dog teeth during upshifting. The left side of Fig. 4 shows an example of a gear shift from third gear to fourth gear, which is an example of upshifting. The right side of Fig. 4 shows an example of a gear shift from second gear to third gear, which is an example of upshifting.

The left side of Figure 4 (3-4UP) shows a time chart for shifting up from third to fourth gear. From the top, the square wave of the gear change command, the square wave of the waiting mechanism release signal, the shift drum displacement line, the 3rd relative angle (the relative angle of dog tooth 33b of the third-speed dog clutch to dog tooth 17a), the coincidence period of the 4th dog (the coincidence period of dog tooth 19a of the fourth-speed dog clutch to dog tooth 37a), the coincidence period of the 3rd dog (the coincidence period of dog tooth 33b of the third-speed dog clutch to dog tooth 17a), and the ignition cut signal are shown.

In the rectangular wave of the gear shift command, time A is the point where dog tooth 19a of the 4th-speed dog clutch meshes with dog tooth 37a.

As described above, the rider operates the shift pedal 51 with his or her foot at any timing. This timing may or may not match the meshing timing calculated by the control unit 45.

When a gear shift command is issued from the shift pedal 51 and the meshing timing does not match, the wait mechanism release signal is not sent and the state shown in Figure 2 is maintained.

When a gear shift command is issued from the shift pedal 51 and the meshing timing is met, a wait mechanism release signal is sent, and the wait mechanism 41 is released taking into account the operating time of the wait mechanism 41 and the shift drum, for example, about 50 m/s, and at point A, the third clutch ring 37 is operated to mesh the dog teeth 37a of the 4th-speed dog clutch with the dog teeth 19a.

At this time, the shift drum is displaced from the 3rd position, where it is stopped by the waiting mechanism 41, to the 4th position as the waiting mechanism 41 releases it.

The relative angle of the dog teeth 33b of the third-speed dog clutch to the dog teeth 17a, which is the 3rd relative angle before and after the gear shift, is 0° when the third-speed dog teeth are engaged. When the third-speed dog teeth disengage and the fourth-speed dog teeth engage, the relative angle of the third-speed dog teeth 17a, 33b coincides every 120°, assuming there are three dog teeth in a revolution.

The coincidence period of the 4th dog, which is the coincidence period of the dog teeth 19a of the 4th-speed dog clutch with the dog teeth 37a, occurs at a constant cycle as described above, and the waiting mechanism 41 is released so that the dog teeth mesh at that timing. After the 4th dog meshes, the relative angle of the 3rd-speed dog teeth shifts as described above, and the relative angle of the 4th-speed dog teeth becomes 0°.

(Ignition cut timing)
In order to reduce the shock torque caused by the inertial mass when shifting up, ignition is cut at the appropriate timing.

The meshing timing is determined based on the relative angle calculated from the number of detected pulses as described above. However, the timing at which the dog teeth of the dog clutch actually meshes has a time delay from the start of the gear shift operation. Therefore, the actual shift timing is estimated by adding this time delay to the sensor signal.

The ignition cut starts a predetermined time before the appropriate timing and continues for a predetermined period of time. The appropriate timing and duration are determined by the torque, inertial mass, and rotational speed applied at the time of shifting.

Figure 4 shows two examples, C and D.

(C) Ignition cut is performed for a set time a specified time before meshing point A.

(D) The ignition cut continues from a predetermined time before to a predetermined time after engagement point A.

This allows the difference in rotation between the clutch ring and the dog teeth between the gears, which rotate relative to each other before meshing, to be reduced, suppressing gear shift shock.

The right side of Figure 4 (2-3UP) shows part of a time chart for shifting up from 2nd gear to 3rd gear.

For example, when shifting up to third gear, the calculated relative angle of dog tooth 33b of the third gear dog clutch to dog tooth 17a produces a deviation t from the actual meshing timing. Therefore, the deviation t is reset by calibration as described above, and the deviation does not accumulate.

[Action and Effect]
In an embodiment of the present invention, the meshing timing for the dog teeth to mesh without hitting is calculated from the rotational positions, etc. detected by a pair of input shaft sensors 43a, 43b, and the standby of the waiting mechanism 41 is released, so that edge hits of the dog teeth 33a, 9a (1st gear), dog teeth 35a, 11a (2nd gear), dog teeth 33b, 17a (3rd gear), dog teeth 37a, 19a (4th gear), dog teeth 35ba, 23a (5th gear), and dog teeth 37b, 27a (6th gear) can be eliminated in response to a shift operation performed at any timing by the operator.

The waiting mechanism 41 can share the elastic body 59 of the quick shift sensor, simplifying the structure.

Figure 5 is a schematic cross-sectional view showing another example of a transmission having a meshing mechanism using dog teeth according to Example 2. Note that the basic configuration of Example 2 is similar to that of Example 1, and the same or corresponding components are designated by the same reference numerals and will not be described again.

[Transmission Overview]
The transmission 1 in Fig. 5 has a structure in which seamless shifting is performed during upshifting, similar to that of the first embodiment. In the transmission 1 of the first embodiment, the dog teeth are engaged by adjusting the engagement timing during downshifting. Therefore, as long as the function of adjusting the engagement timing is working, failure of engagement of the dog teeth will not basically occur.

However, if the function for adjusting mesh timing fails, or if seamless shifting is performed in a transmission that does not have a function for adjusting mesh timing, this can lead to problems as described below.

The transmission 1 of this embodiment 2 has four speeds, and the first and second clutch rings 33 and 35 are both arranged on the output shaft 5. The second clutch ring 35 is arranged between the second gear 13 and the fourth gear 21.

An input gear 71 is supported on the input shaft 3 via a clutch 69. The input gear 71 meshes with a drive gear 73, which is connected to a crankshaft 77 of an engine 75.

Therefore, the output of the engine 75 can be transmitted to the input shaft 3 via the drive gear 73 and input gear 71 by engaging the clutch 69.

The first and second clutch rings 33, 35 are configured to engage with the shift forks 79, 81. The shift pins 83, 85 of the shift forks 79, 81 are arranged to engage with the shift cams 89, 91 of the shift drum 87.

When the shift drum 87 rotates due to a shift operation, the shift cams 89, 91 guide the shift pins 83, 85. This guide causes the first and second clutch rings 33, 35 to selectively move via the shift forks 79, 81 according to the shape of the shift cams 89, 91. This movement allows the dog teeth to selectively mesh according to the shift operation.

The shift drum 87 is provided with a check mechanism 93. The check mechanism 93 has a check cam 95 attached to the end of the shift drum 87. A check ball 99 biased by a check spring 97 supported on the transmission case is in elastic contact with the circumferential surface of the check cam 95.

[Dog clutch]
FIG. 6 is a cross-sectional view of a main portion showing shallow meshing of dog teeth used in the transmission of FIG.

The shape of the dog teeth in Figure 6 is the same for the first-speed dog clutch through the fourth-speed dog clutch. The dog clutches are designed for so-called seamless shifting and have a tooth tip slope for disengagement, which causes a load as described below.

The following describes the 3rd gear dog clutch as a representative for seamless shifting. The other 1st, 2nd, and 4th gear dog clutches are basically the same.

As shown in FIG. 6, the third-speed dog clutch has multiple dog teeth 33b on the first clutch ring 33 and multiple dog teeth 17a on the third-speed gear 17.

The dog teeth 33b and the dog teeth 17a are set to a uniform height in the circumferential direction. The dog teeth 33b and the dog teeth 17a are formed in a spiral shape relative to the axis of the output shaft 5. Therefore, when the dog teeth 33b and the dog teeth 17a engage or disengage, they are relatively spirally guided with a screw-like action.

The tooth tips of the dog teeth 17a of the third-speed gear 17 are provided with tooth tip slopes 101 for disengagement guides. The dog teeth 17a are provided with a drive meshing surface 103 on the rear tooth tip side in the drive torque transmission direction, and a movement guide surface 105 on the tooth base side. The front part of the dog teeth 17a is provided with a coast meshing surface 107.

The tooth tip slope 101 is formed so as to gradually incline in the direction of rotation relative to the rotation axis of the output shaft 5. This inclination allows the tooth tip slope 101 to guide the tooth tip of the other dog tooth 33b by coasting torque, and generate an axial force in the disengagement direction on the first clutch ring 33.

The coasting meshing surface 107 of the dog tooth 17a meshes with the dog tooth 33b during gear shifting and engine braking. The coasting meshing surface 107 rises toward the axis of the output shaft 5 at the inclined lower end of the tooth tip slope 101. The coasting meshing surface 107 is set so as to incline backward from the tooth bottom toward the tooth tip slope 101 in the direction of transmission of the coasting torque relative to the rotation axis of the output shaft 5. This inclination setting of the coasting meshing surface 107 acts to pull the dog tooth 33b in the meshing direction when the dog tooth 33b meshes due to the coasting torque.

The tooth tip surface 108 of the dog tooth 33b is formed as a flat surface or a radius surface (curved surface). The dog tooth 33b is formed with a drive meshing surface 109 and a coast meshing surface 111. The drive meshing surface 109 and the coast meshing surface 111 are inclined to correspond to the drive meshing surface 103 and the coast meshing surface 107 of the dog tooth 17a.

The first meshing position where the coast meshing surfaces 107, 111 mesh is a position where they mesh due to the relative rotation during coast torque of the first clutch ring 33 and the third-speed gear 17. The second meshing position is the shallow meshing position shown in FIG. 6 where the tip of the dog tooth 33b faces the tooth tip slope 101 in the rotational direction.

In other words, when shifting up from third gear through simultaneous meshing to the other gear stage, fourth gear, the moving guide surface 105 moves the first clutch ring 33 so that the dog teeth 33b of third gear move from the first meshing position to the second meshing position.

When shifting up from third to fourth gear, the first and second clutch rings 33, 35 undergo simultaneous meshing in response to the rotation of the shift drum 87 caused by the upshift operation of the shift pedal 51. This simultaneous meshing occurs when the meshing of the first clutch ring 33 connects the third gear 17 to the output shaft 5, and the meshing of the second clutch ring 35 connects the fourth gear 21 to the output shaft 5.

When the third-speed dog clutch is changed from engaged to engaged through this simultaneous engagement, the third-speed dog teeth 17a, 33b receive a relative torque, causing the tip of the dog tooth 33b to abut against the tip slope 101 of the dog tooth 17a, and moving the first clutch ring 33 away from the third-speed gear 17.

In this case, the relative rotation is caused by the coasting torque generated in the lower gears and the drive torque generated in the upper gears due to the simultaneous engagement of the first and second clutch rings 33, 35.

When shifting down from fourth gear to third gear, the second clutch ring 35 disengages from the engagement in response to the rotation of the shift drum 87 caused by the downshift operation of the shift pedal 51, and receives a moving force such that the dog teeth 33b of the first clutch ring 33 are brought to the first engagement position with respect to the dog teeth 17a of the third gear 17.

(Relative position of the shift cam and shift drum when shifting down)
Fig. 7 is a development of a main part showing the relationship between a shift pin and a drum groove according to a comparative example. Fig. 8 is a cross-sectional view of a main part showing an example of failure of meshing of dog teeth used in the transmission of Fig. 5. Fig. 9 is a development of a shift drum showing the position of a shift pin used in the transmission of Fig. 5. Fig. 10 is a development of a main part of the shift drum of Fig. 9. Fig. 11 is an explanatory diagram of a check mechanism of the shift drum.

Continuing with the example of shifting down from 4th gear to 3rd gear, in the conventional comparative example, as shown in FIG. 7, the shift pin 83 to be shifted is moved to the cam lobe apex 115 when shifting down. In other words, the shift pin 83 is moved to the cam lobe apex 115 by the rotation of the shift drum 87, providing a moving force to the first clutch ring 33.

At this time, if dog teeth 33b and dog teeth 17a mesh correctly in the first meshing position, there is no problem, but meshing may fail, resulting in the state shown in Figure 8.

If torque T continues to be transmitted in this state shown in FIG. 8, the tooth tip of dog tooth 33b strengthens the contact force against the tooth tip slope 101 of dog tooth 17a. This contact force causes the dog tooth 33b to receive a guide force against the tooth tip slope 101, generating an excessive axial force P.

This axial force P presses the shift pin 83 against the cam lobe apex 115 as shown in FIG. 7, causing malfunction of the shift mechanism.

In contrast, in the second embodiment, as shown in Figures 9 and 10, the shift pin 83 is moved to a position shifted forward rather than to the cam lobe apex 115, so that a moving force is applied to the first clutch ring 33.

Therefore, when axial force P is generated, the thrust of the shift pin 83 presses the cam lobe of the shift drum 87, driving the shift drum 87 to rotate, and the thrust of the shift pin 83 can be released.

As shown in Figures 5 and 11, the rotation of the shift drum 87 activates the check mechanism 93 attached to the shift drum 87. This action causes the check cam 95 to rotate together with the shift drum 87. This rotation causes the cam lobe of the check cam 95 to compress the check spring 97 via the check ball 99. The compressed check spring 97 stores elastic energy for return.

Therefore, when the timing of meshing between dog teeth 17a and dog teeth 33b is next met, the elastic energy of the check spring 97 is released, and the check ball 99 falls between the cam lobes of the check cam 95, and the check cam 95 is rotated.

This rotation of the check cam 95 causes the rotation of the shift drum 87 to return to the position shown in FIG. 9. This causes the first clutch ring 33 to receive further axial force, for example, from the movement biasing mechanism 117 provided between the first clutch ring 33 and the output shaft 5, so that the first clutch ring 33 can properly mesh in the first meshing position.

Here, the moving biasing mechanism 117 is provided with a check ball 119, for example, on the output shaft 5 side and biased radially outward by a spring (not shown). The check ball 119 is configured to abut against a slope formed on the inner circumference of the first clutch ring 33. The slope is formed on both sides of the first clutch ring 33 in the axial direction. Such a moving biasing mechanism is also provided with the same structure between the second clutch ring 35 and the output shaft 5.

Figure 12 is a diagram showing the relationship between the meshing state of the dog teeth and the position of the shift pin relative to the drum groove in a comparative example. Figure 13 is a diagram showing the relationship between the meshing state of the dog teeth and the position of the shift pin relative to the drum groove in Example 2.

Figures 12 and 13 summarize the operation of Example 2 along with a comparative example.

In both Figures 12 and 13, the operation of each part is illustrated simply in four rows and three columns. The first row shows the relationship between the shift drum (drum groove) and the shift pin, the second row shows the check mechanism, the third row shows the dog clutch (developed view), and the fourth row shows the shift drum and dog clutch (developed view).

In both Figures 12 and 13, the first column shows the downshift when the rotation speed is N1 < N2, the second column shows the downshift success when the rotation speed is N1 > N2, and the third column shows the downshift failure when the rotation speed is N1 > N2.

In the comparative example of FIG. 12, in a downshift when N1<N2, even if the shift pin 83 is guided to the cam lobe apex 115 by the rotation of the shift drum 87, the dog teeth 17, 33 are engaged at the first engagement position by the drive engagement surfaces 103, 109, so the excessive axial force P described in FIG. 6 is not generated.

In the comparative example of FIG. 12, in a successful downshift when N1>N2, even if the shift pin 83 is guided to the cam lobe apex 115 by the rotation of the shift drum 87, the dog teeth 33 immediately move to the first meshing position and mesh with the coast meshing surfaces 107, 111, so the excessive axial force P described in FIG. 6 does not occur.

In the comparative example of FIG. 12, if a downshift fails when N1>N2, even if the shift pin 83 is guided to the cam lobe apex 115 by the rotation of the shift drum 87, if meshing fails, the excessive axial force P described in FIG. 6 is generated.

In contrast, the second embodiment operates as shown in FIG. 13. In FIG. 13, the downshift when N1<N2 and the downshift success when N1>N2 are not significantly different from the comparative example in FIG. 12.

In the case of a downshift failure when N1>N2 in FIG. 13, the shift pin 83 is positioned in front of the cam lobe apex 115, and axial force P is generated in the same manner as above. However, the thrust of the shift pin 83 presses the cam lobe of the shift drum 87, which rotates the shift drum 87 and releases the thrust of the shift pin 83. Also, the check mechanism 93 and the movement biasing mechanism work to complete the meshing of the dog teeth 17a, 33b to the first meshing position at the next meshing timing.

1 Transmission 3 Input shaft 5 Output shaft 7 1st gear 9 1st gear (the other rotating member)
11 2nd gear (the other rotating member)
13 2nd gear 15 3rd gear 17 3rd gear (the other rotating member)
19 4th gear (the other rotating member)
21 4th gear 23 5th gear (the other rotating member)
25 5th gear 27 6th gear (the other rotating member)
29 6th speed gear 31 Meshing mechanism 33 First clutch ring (one of the rotating members)
35 Second clutch ring (one rotating member)
37 Third clutch ring (one rotating member)
33a, 33b, 35a, 35b, 37a, 37b, 9a, 11a, 17a, 19a, 23a, 27a Dog teeth 39 Shift mechanism 41 Waiting mechanism 43a Input shaft sensor (sensor)
43b Output shaft sensor (sensor)
45 Control unit 57 Contact plate (transmission unit)
58 Interlocking rod (transmission part)
59 Elastic body (transmission part)
60 Arm connecting portion 61 Shift drive arm 65 Release mechanism

Claims (5)

One rotating member that is shiftable in an axial direction;
a second rotating member for transmitting torque between the first rotating member and the second rotating member;
dog teeth that are provided on each of the one and the other rotating members and that mesh with each other in a rotational direction to transmit the torque;
a shift mechanism that shifts the one of the rotors by a shift operation to engage the dog teeth;
a waiting mechanism provided in the shift mechanism for waiting for the shift movement of the one rotating body due to the shift operation;
a pair of sensors for separately detecting rotational positions of the dog teeth of the one and the other rotating members;
a control unit that calculates a meshing timing for the dog teeth to mesh without hitting each other based on the rotational positions detected by the pair of sensors and releases the waiting mechanism from standby;
An engaging mechanism equipped with 2. The engagement mechanism of claim 1,
The control unit releases the waiting mechanism from waiting while reducing a rotation difference or an input torque between the one and the other rotating members.
Meshing mechanism. 3. The meshing mechanism of claim 1 or 2,
The one rotating member is a clutch ring provided on the input shaft or the output shaft,
the other rotating member is one of the constant meshing speed change gears provided on the input shaft or the output shaft,
When the dog teeth of the clutch ring mesh with the dog teeth of one of the speed change gears, torque is transmitted between the input and output shafts via the constantly meshing speed change gear.
Meshing mechanism. 3. The meshing mechanism of claim 1 or 2,
The sensor includes an input shaft sensor that detects a rotation pulse of the input shaft and an output shaft sensor that detects a rotation pulse of the output shaft.
Meshing mechanism. 3. The meshing mechanism of claim 1 or 2,
The waiting mechanism includes a transmission unit, a shift drive arm, and a release mechanism.
The transmission portion transmits an operating force of the shift mechanism through an elastic body,
The shift drive arm is operated by an operating force via the transmission unit,
The release mechanism releasably stops the operation of the shift drive arm, accumulates the operating force in the elastic body, and performs the release under the control of the control unit.
Meshing mechanism.

Images