JP5860330B2 - transmission - Google Patents

Description

  The present invention relates to a transmission that prevents torque loss during gear shifting.

  A first gear (low gear) and a second gear (high gear), which are rotatably mounted on the output shaft of the transmission, are used as automobile transmissions that prevent torque loss during gear shifting. A gearshift comprising: a hub fixed to a shaft between the gear and the second gear; and a first sleeve ring and a second sleeve ring mounted on the hub so as to be movable in the axial direction and not to be relatively rotatable in the circumferential direction. A machine is known (Patent Document 1).

  In such a transmission, when both the first and second sleeve rings are moved to the first gear side, the rotation of the first gear is transmitted to the hub only by the first sleeve ring. Therefore, it is possible to move only the second sleeve ring to which the torque is not applied to the second gear side without moving the first sleeve ring transmitting the torque from the position. When the second sleeve ring is moved to the second gear side, the rotation of the second gear is transmitted to the hub by the second sleeve ring. At the same time, the first sleeve ring is separated from the first gear. The shift from the first gear to the second gear is completed without running out of torque.

JP 2009-536713 A

  In the above-described conventional transmission, two shift sleeves (first and second sleeve rings) disposed between the first gear and the second gear to be shifted are used for one shift operation. , It is necessary to control movement separately with a time difference. That is, the first and second shift rods are attached to the first and second shift forks engaged with the first and second sleeve rings, respectively, and the first and second shift rods are linked to provide a time difference. If the movement is not controlled by separate actuators, the speed cannot be changed, resulting in complicated operation system structures such as shift control and shift linkage by the actuators.

  In general, a transmission for an automobile includes not only the first and second gears described above, but also a large number of transmission gears according to the number of shift stages. If two shift sleeves are arranged between the shift sleeves, shift forks are engaged with the shift sleeves, and shift rods are attached to the shift forks, the number of shift rods is twice that of a normal manual transmission. End up. Therefore, the shift rods must all be controlled by separate actuators, and the shift control and the operation system structure become complicated.

  The object of the present invention, which was created in view of the above circumstances, is to provide a transmission capable of simplifying the shift rod movement control and operation system structure at the time of shifting in a transmission that prevents torque loss during shifting. There is to do.

  The transmission according to the present invention created to achieve the above object includes a first gear that is rotatably mounted on a shaft and has a first dog projecting from a side surface thereof, a rotatably mounted on the shaft, and a side surface. Between the second gear with the second dog projecting from the first gear and the second gear and the first gear so as to rotate integrally with the shaft and be movable in the axial direction of the shaft. The first sleeve ring having a first key that engages with the leading surface of the first and the other end engages with the trailing surface of the second dog, and rotates integrally with the shaft between the second gear and the first gear. And a second sleeve ring having a second key which is provided so as to be movable in the axial direction of the shaft and has one end engaged with the trailing surface of the first dog and the other end engaged with the leading surface of the second dog; A first shift fork engaged with the first sleeve ring; A second shift fork engaged with the sleeve ring, a first shift fork, a shift rod connected to the second shift fork and moved in the axial direction in conjunction with a shift operation; a shift rod and a first shift fork; A holding mechanism provided between each of the second shift forks, the holding mechanism holds the positions of the first shift fork and the second shift fork with respect to the shift rod at the initial position, the first key, the second The key allows the shift rod to move with the first dog and the second dog engaged, and exhibits a return force for returning the first shift fork and the second shift fork to their initial positions. It is a transmission.

  In the transmission of the present invention, the first key has a leading claw that engages with the leading surface of the first dog at one end and a trailing claw that engages with the trailing surface of the second dog at the other end. The second key has a trailing claw that engages with the trailing surface of the first dog at one end and a leading claw that engages with the leading surface of the second dog at the other end. Each leading and trailing surface of the second dog is formed in a reverse taper shape so that it spreads from the root toward the tip. Each leading claw and trailing claw of the first key and second key The return force of the holding mechanism is related to each leading claw and trailing claw on each leading surface and trailing surface during gear shifting. It may be set weaker than the engaging force due to the reverse taper of the while.

  In the transmission of the present invention, the first shift fork has a first insertion portion through which the shift rod is inserted so as to be movable in the axial direction, and the second shift fork is inserted so that the shift rod is movable in the axial direction. The holding mechanism has a first detent mechanism provided between the first insertion part and the shift rod, and a second mechanism provided between the second insertion part and the shift rod. And a detent mechanism.

  In the transmission of the present invention, the first detent mechanism is formed along the axial direction on the shift rod inserted through the first insertion portion, and the first groove portion whose center along the axial direction is deeper than both ends, A first ball or a first roller disposed in the first groove; and a first urging unit that presses the first ball or the first roller against the first groove. The second detent mechanism is inserted into the second insertion part. A shift rod formed along the axial direction and having a center along the axial direction deeper than both ends, a second ball or second roller disposed in the second groove, and a second ball or second You may provide the 2nd biasing means which presses a roller to a 2nd groove part.

  In the transmission of the present invention, the first groove portion is formed to be connected to the steeply inclined portion where the first ball or the first roller abuts when the first insertion portion with respect to the shift rod is in the initial position, and the steeply inclined portion. The second groove portion is formed so as to be connected to the steeply inclined portion where the second ball or the second roller abuts when the second insertion portion with respect to the shift rod is in the initial position, and the steeply inclined portion. You may have a gentle inclination part.

  In the transmission according to the present invention, a holding mechanism is provided between the shift rod that is moved in conjunction with the shift operation, the first shift fork, and the second shift fork. The holding mechanism holds the positions of the first shift fork and the second shift fork with respect to the shift rod at the initial position, and is also related to the first key and the second shift fork of the first shift sleeve engaged with the first shift fork. The second key of the combined second shift sleeve allows the shift rod to move with the first dog of the first gear engaged with the second dog of the second gear, and the first shift fork, second gear Demonstrates the return force to return the shift fork to the initial position.

  In the transmission having this holding mechanism, the first shift fork and the second shift fork can be moved integrally with the shift rod by moving the shift rod in the axial direction, and the first key and the first Only the shift fork engaged with the shift sleeve of the torque-free key can be moved while the key transmitting torque among the two keys is engaged with the first dog or the second dog. Therefore, when shifting, shifting without any torque interruption can be achieved only by moving the single shift rod connected to the first shift fork and the second shift fork in the axial direction. System structure can be simplified.

1 is an overall view showing an outline of a transmission according to an embodiment of the present invention. It is a disassembled perspective view which shows the principal part of the said transmission. It is an assembly perspective view which shows the principal part of the said transmission. (A) is a sectional side view (neutral state) showing the main part of the transmission, (b) is the first dog of the first gear, the second dog of the second gear, the first key, the second key in the neutral state. It is the schematic which shows typically the positional relationship of these. It is explanatory drawing which shows the mode of the upshift at the time of the acceleration by the said transmission. (A) is a sectional side view shifted to the first gear (low gear), (a1) is a schematic diagram in the state of (a), and (a2) is a schematic diagram before reaching (a1). (B) is a sectional side view in the middle of completing the shift-up from the first gear (low gear) to the second gear (high gear), and (b1) is a schematic view in the state (b). (C) is a sectional side view after the shift to the second gear (high gear) is completed, and (c1) is a schematic view in the state of (c). It is explanatory drawing which shows the mode of the downshift at the time of the deceleration by the said transmission. (A) is side sectional drawing shifted to the 2nd gear (high gear), (a1) is the schematic in the state of (a). (B) is a side sectional view in the middle of completing the downshift from the second gear (high gear) to the first gear (low gear), and (b1) is a schematic diagram in the state of (b). (C) is a side sectional view in which the shift to the first gear (low gear) is completed, and (c1) is a schematic view in the state of (c). It is explanatory drawing which shows the modification of the 1st, 2nd groove part which comprises the 1st, 2nd detent mechanism as a holding mechanism of the said transmission, (a) is a ball | bowl arrange | positioned at the steeply inclined part in the initial position. FIG. 4B is a schematic diagram illustrating a state where the ball is displaced from the initial position and is disposed on the gently inclined portion.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Outline of transmission 1)
FIG. 1 schematically shows a transmission 1 for an automobile according to an embodiment of the present invention. The transmission 1 according to the present embodiment includes a main shaft (input shaft) 4 and a counter shaft (output shaft) 5 that are supported by a transmission case 2 in parallel by bearings 3. The main shaft 4 is connected to the crankshaft of the engine 7 via the clutch 6, and a bevel gear 9 connected to the differential mechanism 8 is provided at the end of the countershaft 5.

  A first-speed main gear 1m and a second-speed main gear 2m are fixed to the main shaft 4, and a first-speed counter gear 1c that meshes with the first-speed main gear 1m is fixed to the countershaft 5 that is second-speed meshed with the second-speed main gear 2m. A counter gear 2c is rotatably mounted. In the actual transmission 1, not only the gears 1m, 2m, 1c, and 2c described above, but also a plurality of gears are provided according to the number of shift stages.

(Parts of transmission 1)
In the present embodiment, the counter shaft 5 corresponds to the shaft in the claims, the first speed counter gear 1c corresponds to the first gear, and the second speed counter gear 2c corresponds to the second gear. 2 is an exploded perspective view of the main part of the transmission 1, FIG. 3 is an assembled perspective view of the main part, FIG. 4A is a side sectional view of the main part, and FIG. 4B is a schematic schematic view of the main part. Each one is shown.

  A first dog 1d projects from the side surface of the first gear (first speed counter gear) 1c, and a second dog 2d projects from the side surface of the second gear (second speed counter gear) 2c. A hub 10 is fixed to a shaft (counter shaft shown in FIG. 1) 5 between the first gear 1c and the second gear 2c. The hub 10 includes a first sleeve ring 1 s having a first key 1 k and a second sleeve ring 2 s having a second key 2 k so as to rotate integrally with the hub 10 and in the axial direction of the hub 10. It is provided movably.

A first shift fork 1f is engaged with the first sleeve ring 1s, and a second shift fork 2f is engaged with the second sleeve ring 2s. A shift rod 11 is connected to the first shift fork 1f and the second shift fork 2f. A holding mechanism 12 is provided between the shift rod 11 and the first shift fork 1f and the second shift fork 2f. In the actual transmission 1, a plurality of gears are arranged according to the number of gears, and a plurality of sets of these components are arranged accordingly.
Hereinafter, these components will be described.

(1st dog 1d, 2nd dog 2d)
As shown in FIGS. 1, 2, and 4A, the first gear 1c has a first dog 1d projecting on the side surface facing the second gear 2c, and the second gear 2c has A second dog 2d protrudes from the side surface facing the first gear 1c. A plurality of first dogs 1d and second dogs 2d are arranged at equal intervals in the circumferential direction of the first gear 1c and the second gear 2c, respectively. In the present embodiment, six first dogs 1d and second dogs 2d are arranged at intervals of 60 degrees on the side surfaces of the first gear 1c and the second gear 2c, respectively. The number may be three at 120 degree intervals, four at 90 degree intervals, five at 72 degree intervals, or seven or more.

  As shown in FIGS. 2 and 4 (b), the first dog 1d includes a leading surface (drive tooth surface) 1df serving as a front surface in the rotational direction of the first gear 1c and a trailing surface serving as a rear surface in the rotational direction. The leading surface 1df and the trailing surface 1dr are formed in a reverse taper shape so as to widen from the root toward the tip. Similarly, the second dog 2d has a leading surface 2df which is a front surface in the rotational direction of the second gear 2c, and a trailing surface 2dr which is a rear surface in the rotational direction. The leading surface 2df and the trailing surface 2dr is formed in a reverse taper shape so as to widen toward the tip from the root.

(Hub 10)
As shown in FIGS. 1 and 4A, the counter shaft 5 between the first gear 1c and the second gear 2c is relatively rotated in the circumferential direction so that the hub 10 rotates integrally with the counter shaft 5. It is mounted impossible. 2 and 4A, a plurality of hub grooves 13 formed along the axial direction of the countershaft 5 are provided on the outer peripheral surface of the hub 10 at equal intervals in the circumferential direction. ing. In the present embodiment, the number of hub grooves 13 is twelve, but is not limited to twelve, and may be two or more.

  As shown in FIG. 2, in each hub groove 13, a first key 1k of the first sleeve ring 1s and a second key 2k of the second sleeve ring 2s are alternately engaged in the circumferential direction. The counter shaft 5 is movable in the axial direction. Each hub groove 13 is formed so that the opening is narrower than the bottom. When the hub 10 is rotated by the rotation of the countershaft 5, the first key 1k and the second key 2k that receive centrifugal force are hub grooves. It is set so as not to protrude outward in the radial direction from the 13 openings.

(First sleeve ring 1s, second sleeve ring 2s)
As shown in FIGS. 2 and 4A, the first sleeve ring 1s connects the first key 1k accommodated in the hub groove 13 every other in the circumferential direction and the outer surface of each first key 1k. Thus, the first ring 1r is formed in a ring shape. The first key 1k is accommodated in the hub groove 13 so as to be movable in the axial direction, and engages with the leading surface (drive tooth surface) 1df of the first dog 1d at one end as shown in FIG. A leading claw (driving tooth claw) 1 kf is formed, and a trailing claw (driving tooth claw) 1 kr engaging with a trailing surface (driven tooth surface) 2 dr of the second dog 2 d is formed at the other end. Yes. The leading claw 1kf and the trailing claw 1kr are formed in a reverse taper shape so as to engage with the leading surface 1df of the first dog 1d and the trailing surface 2dr of the second dog 2d, respectively.

  Similarly, the second sleeve ring 2s is formed in a ring shape so as to connect the second keys 2k housed in the hub groove 13 every other circumferential direction and the outer surface of each second key 2k. It is comprised from the ring 2r. The second key 2k is accommodated in the hub groove 13 so as to be movable in the axial direction. A trailing claw 2kr that engages with the trailing surface 1dr of the first dog 1d is formed at one end, and the second dog 2k is formed at the other end. Leading claws 2kf that engage with the 2d leading surface 2df are formed. These leading claw 2kf and trailing claw 2kr are formed in a reverse taper shape so as to engage with the leading surface 2df of the second dog 2d and the trailing surface 1dr of the first dog 1d, respectively.

(First shift fork 1f, second shift fork 2f)
As shown in FIGS. 2 and 4A, the first shift fork 1f is engaged with the first ring 1r of the first sleeve ring 1s, and the second ring 2r of the second sleeve ring 2s is engaged with the second ring 2r. A 2 shift fork 2f is engaged. The first shift fork 1f includes a first engagement portion 1fa having a U-shaped cross section engaged with the first ring 1r over a substantially half circumference, and a first insertion through which the shift rod 11 is inserted so as to be movable in the axial direction. Part 1fb. Similarly, in the second shift fork 2f, a second engagement portion 2fa having a U-shaped cross section engaged with the second ring 2r over a substantially half circumference and a shift rod 11 are inserted so as to be movable in the axial direction. A second insertion portion 2fb.

(Shift rod 11)
As shown in FIGS. 2 and 4 (a), the shift rod 11 is inserted into the first insertion portion 1fb of the first shift fork 1f and the second insertion portion 2fb of the second shift fork 2f. In conjunction with this, it is moved in parallel with the counter shaft 5. The shift rod 11 is moved in parallel with the countershaft 5 by an actuator (not shown) or by a link mechanism (shift linkage: not shown) linked to a shift operation of the shift lever by the driver. The actuator moves the shift rod 11 by computer control according to the traveling state of the vehicle or according to the shift operation of the shift lever by the driver.

(Holding mechanism 12)
As shown in FIGS. 2 and 4A, between the shift rod 11 and the first insertion portion 1fb of the first shift fork 1f, between the shift rod 11 and the second insertion portion 2fb of the second shift fork 2f. Is provided with a holding mechanism 12. The holding mechanism 12 holds the positions of the first shift fork 1f and the second shift fork 2f with respect to the shift rod 11 at the initial position, and the first key 1k of the first sleeve ring 1s and the second key of the second sleeve ring 2s. 2k is engaged with the first dog 1d of the first gear 1c and the second dog 2d of the second gear 2c, allowing relative movement of the shift rod 11 with respect to the first shift fork 1f and the second shift fork 2f, In addition, a return force for returning the first shift fork 1f and the second shift fork 2f to the initial position is exhibited. The return force is determined by the leading claws 1kf and 2kf of the first key 1k and the second key 2k, the trailing claws 1kr and 2kr at the first dog 1d and the leading surfaces 1df and 2df of the second dog 2d at the time of shifting. It is set to be weaker than the engaging force due to the reverse taper when engaged with the surfaces 1dr and 2dr.

  As shown in FIG. 4A, the holding mechanism 12 includes a first detent mechanism 1det provided between the first insertion portion 1fb of the first shift fork 1f and the shift rod 11, and a second shift fork 2f. A second detent mechanism 2det provided between the second insertion portion 2fb and the shift rod 11; The first detent mechanism 1det includes a first groove portion 1g formed in the shift rod 11 inserted through the first insertion portion 1fb, a first ball 1b disposed in the first groove portion 1g, and a first ball 1b. 1st biasing means 1x pressed against groove 1g is provided. The second detent mechanism 2det includes a second groove portion 2g formed in the shift rod 11 inserted through the second insertion portion 2fb, a second ball 2b disposed in the second groove portion 2g, and a second ball 2b. And a second urging means 2x that presses against the groove 2g.

(First detent mechanism 1det, second detent mechanism 2det)
As shown in FIG. 4 (a), the first groove 1g of the first detent mechanism 1det is formed along the axial direction in the shift rod 11 inserted through the first insertion part 1fb of the first shift fork 1f. The center along the direction is deeper than both ends. Similarly, the second groove portion 2g of the second detent mechanism 2det is formed along the axial direction on the shift rod 11 inserted through the second insertion portion 2fb of the second shift fork 2f, and the center along the axial direction is at both ends. It is deeper than. As shown in FIG. 4A, the cross-sectional shapes of the first groove portion 1g and the second groove portion 2g are V-shaped in the present embodiment, but are not limited to this, and may be U-shaped or inverted trapezoidal shapes. I do not care.

  The first ball 1b disposed in the first groove 1g of the first detent mechanism 1det is mounted on the end of the first holder 1h formed in a substantially cylindrical shape, and is disposed in the second groove 2g of the second detent mechanism 2det. The second ball 2b thus formed is attached to the end of the second holder 2h formed in a substantially cylindrical shape. The first holder 1h is urged toward the first groove 1g by a first spring (coil spring) 1xb constituting the first urging means 1x, and the second holder 2h is the second urging means 2x constituting the second urging means 2x. Two springs (coil springs) 2xb are biased toward the second groove 2g. A first roller and a second roller may be used instead of the first ball 1b and the second ball 2b.

  The first spring 1xb of the first detent mechanism 1det is accommodated in a cylindrical first spring accommodating portion 1y provided in the first insertion portion 1fb of the first shift fork 1f, and the second spring 2xb of the second detent mechanism 2det. Is housed in a cylindrical second spring housing portion 2y provided in the second insertion portion 2fb of the second shift fork 2f. A first lid 1z is attached to the first spring accommodating portion 1y, and a second lid 2z is attached to the second spring accommodating portion 2y. The outer peripheral surface of the first holder 1h is in sliding contact with the inner peripheral surface of the first spring housing portion 2y, and the outer peripheral surface of the second holder 2h is in sliding contact with the inner peripheral surface of the second spring housing portion 2y.

  The first spring 1xb of the first detent mechanism 1det takes a reaction force on the first lid 1z and presses the first ball 1b against the first groove 1g via the first holder 1h. Accordingly, the position of the first shift fork 1f with respect to the shift rod 11 is held at the initial position (the V-shaped bottom of the first groove 1g). The second spring 2xb of the second detent mechanism 2det takes a reaction force against the second lid 2z and presses the second ball 2b against the second groove 2g via the second holder 2h. Accordingly, the position of the second shift fork 2f with respect to the shift rod 11 is held at the initial position (the V-shaped bottom of the second groove 2g). The first holder 1h and the second holder 2h are omitted, and the first ball 1b and the second ball 2b are directly pressed against the first groove 1g and the second groove 2g by the first spring 1xb and the second spring 2xb. Also good.

(Shift up during acceleration)
The acceleration shift up of the transmission 1 described above will be described with reference to FIGS. FIG. 5 (a) is a side cross-sectional view shifted to the first gear (first speed counter gear) 1c, and FIG. 5 (a1) is the first dog 1d of the first gear 1c in the state of FIG. FIG. 5A is a schematic diagram schematically showing a positional relationship among the second dog 2d of the two gears 2c, the first key 1k, and the second key 2k, and FIG. 5A2 is a schematic diagram before reaching FIG. 5A1. FIG. 5B is a side sectional view in the middle of completing the shift-up from the first gear 1c to the second gear (second speed counter gear) 2c, and FIG. 5B1 is a schematic view in the state of FIG. 5B. It is. FIG. 5 (c) is a side sectional view after the shift to the second gear 2c is completed, and FIG. 5 (c1) is a schematic view in the state of FIG. 5 (c).

  When the shift rod 11 in the neutral state of FIG. 4 is moved (shifted) to the first gear (first speed counter gear) 1c side, the first shift fork 1f and the second shift fork 2f are moved as shown in FIG. Both the first detent mechanism 1det and the second detent mechanism 2det move to the first gear 1c side and, as shown in FIG. 5 (a1), the first sleeve ring 1s engaged with the first shift fork 1f. The leading claw 1kf of the first key 1k is engaged with the leading surface 1df of the first dog 1d of the first gear 1c.

  As shown in FIG. 5A2, when the second key 2k collides with the first dog 1d at the moment of shifting, the second detent mechanism 2det between the second shift fork 2f and the shift rod 11 Since the two-shift fork 2f is shifted with respect to the shift rod 11 and enters a waiting state, the state shown in FIG. Here, the waiting state means that the second key 2k contacts the first dog 1d and cannot move further to the first gear 1c side, but the second key 2k is between the second shift fork 2f and the shift rod 11. The second detent mechanism 2det is biased toward the first gear 1c.

  Therefore, when the first dog 1d moves away from the second key 2k as the first gear 1c rotates from the state shown in FIG. 5A2 (waiting state), the second key 2k is biased by the second detent mechanism 2det. To move to the first gear 1c side, and the state shown in FIG. The same applies when the first key 1k collides with the first dog 1d at the moment of shifting. As a result, the first speed state shown in FIG. 5A1 is established, and torque is transmitted by the first key 1k during engine acceleration, and no torque is applied to the second key 2k (torque free).

  During acceleration, when shifting from the first speed state of FIG. 5 (a) to the second speed, the shift rod 11 is moved to the second gear (second speed counter gear) 2c side as shown in FIG. 5 (b). (shift. Then, only the torque-free second key 2k moves to the second gear 2c side while the first key 1k to which the torque is applied does not move and remains engaged with the first dog 1d. That is, the first shift fork 1f engaged with the first sleeve ring 1s having the first key 1k is engaged with the second sleeve ring 2s having the second key 2k without moving to the second gear 2c side. Only the second shift fork 2f moves integrally with the shift rod 11 toward the second gear 2c.

  At this time, as shown in FIG. 5B, the ball 1b of the first detent mechanism 1det between the first shift fork 1f and the shift rod 11 engaged with the first sleeve ring 1s having the first key 1k. Is shifted from the initial position (waiting state). In other words, the return force of the first detent mechanism 1det is set to be weaker than the engagement force due to the reverse taper when the leading claw 1kf of the first key 1k is engaged with the leading surface 1df of the first dog 1d at the time of shifting. Therefore, the first key 1k does not come out of the first dog 1d and continues to transmit torque.

  As shown in FIG. 5 (b1), the leading claw 2kf of the second key 2k moved to the second gear 2c side is the second gear (second speed counter gear) 2c is the first gear (first speed counter gear) 1c. Since it is rotating faster than the first, it engages with the leading surface 2df of the second dog 2d of the second gear 2c. That is, the relative rotation direction of the second gear 2c viewed from the first key 1k and the second key 2k in the relationship of the gear ratio is the direction of arrow A in FIG. 5 (b1), so that the leading surface 2df of the second dog 2d is Engages with the leading claw 2kf of the second key 2k. By this engagement, the second speed state is established, and torque is transmitted by the second key 2k.

  Here, as shown in FIG. 5 (b1), the moment when the leading surface 2df of the second dog 2d is engaged with the leading claw 2kf of the second key 2k, that is, the moment when the first gear is shifted up to the second gear, The engine speed (rpm) falls according to the gear ratio between the first speed and the second speed. For this reason, the rotation speed of the first gear (first speed counter gear) 1c decreases, and the relative rotation direction of the first gear 1c viewed from the first key 1k and the second key 2k is the direction of arrow B in FIG. 5 (c1). Thus, the leading surface 1df of the first dog 1d is separated from the leading claw 1kf of the first key 1k. Thereby, the transmission of torque in the first speed state by the first key 1k is completed. The first key 1k separated from the first dog 1d is moved to the second gear 2c side by the return force of the first detent mechanism 1det, and therefore does not interfere with the first dog 1d.

  As described above, when shifting from the first speed to the second speed during engine acceleration, the first shift fork 1f and the second shift fork 2f are respectively connected to the first detent mechanism 1det and the second detent mechanism 2det. The connected shift rod 11 is moved from the first gear 1c side to the second gear 2c side. Then, with the first key 1k transmitting torque in the first speed state engaged with the first dog 1d, only the torque-free second key 2k is moved to the second gear 2c side and the second dog 2d Can be shifted up without running out of torque. That is, when shifting up during acceleration, if only the single shift rod 11 connecting the first shift fork 1f and the second shift fork 2f is moved in the axial direction from the first gear 1c side to the second gear 2c side. As a result, the movement control of the shift rod 11 and the operation system structure can be simplified. Note that the movement of the shift rod 11 is the same as in the case of shifting up a normal manual transmission.

(Shifting down during deceleration)
With reference to FIG. 6, the above-described shift down during deceleration of the transmission 1 will be described. 6A is a side cross-sectional view shifted to the second gear 2c, FIG. 6A1 is a first dog 1d of the first gear 1c in the state of FIG. 6A, and a second of the second gear 2c. It is the schematic which shows typically the positional relationship of the dog 2d, the 1st key 1k, and the 2nd key 2k. FIG. 6B is a side sectional view in the middle of completing the downshift from the second gear 2c to the first gear 1c, and FIG. 6B1 is a schematic view in the state of FIG. FIG. 6C is a side sectional view after the shift to the first gear 1c is completed, and FIG. 6C1 is a schematic view in the state of FIG.

  6 (a) and 6 (a1) show a case where the engine speed is changed from the engine acceleration state to the engine deceleration state at the second speed shown in FIGS. When the vehicle is decelerated, the engine is braked so that the engine is turned by the wheels of the vehicle. Therefore, as shown in FIG. 5C1, the leading surface 2df of the second dog 2d until then is the leading claw 2kf of the second key 2k. From the engaged state, as shown in FIG. 6 (a1), the trailing surface 2dr of the second dog 2d is engaged with the trailing claw 1kr of the first key 1k. Accordingly, torque is transmitted by the first key 1k, and the second key 2k is in a torque-free state.

  For this reason, as shown in FIG. 6B, when the shift rod 11 is moved (shifted) toward the first gear 1c, the first key 1k to which the torque is applied does not move but engages with the second dog 2d. In the state, only the torque-free second key 2k moves to the first gear 1c side. That is, the first shift fork 1f engaged with the first sleeve ring 1s having the first key 1k is engaged with the second sleeve ring 2s having the second key 2k without moving to the first gear 1c side. Further, only the second shift fork 2f moves integrally with the shift rod 11 to the first gear 1c side.

  At this time, as shown in FIG. 6 (b), the ball 1b of the first detent mechanism 1det between the first shift fork 1f and the shift rod 11 engaged with the first sleeve ring 1s having the first key 1k. Is shifted from the initial position (waiting state). That is, the return force of the first detent mechanism 1det is greater than the engagement force due to the reverse taper when the trailing claw 1kr of the first key 1k is engaged with the trailing surface 2dr of the second dog 2d at the time of shifting. Since the setting is weak, the first key 1k does not come out of the second dog 2d and continues to transmit torque.

  As shown in FIG. 6 (b1), the trailing claw 2kr of the second key 2k moved to the first gear 1c side is the first gear (first speed counter gear) 1c is the second gear (second speed counter gear). Since it rotates later than 2c, it engages with the trailing surface 1dr of the first dog 1d of the first gear 1c. That is, the relative rotation direction of the first gear 1c viewed from the first key 1k and the second key 2k in the relationship of the gear ratio is the direction of arrow C in FIG. 6 (b1), and therefore the trailing surface 1dr of the first dog 1d. Engages the trailing claw 2kr of the second key 2k. By this engagement, the first speed state is established, and torque is transmitted by the second key 2k.

  Here, as shown in FIG. 6 (b1), the moment when the trailing surface 1dr of the first dog 1d is engaged with the trailing claw 2kr of the second key 2k, that is, the moment when the gear shifts down from the second speed to the first speed. The engine speed (rpm) increases according to the gear ratio between the first speed and the second speed. Therefore, the rotation speed of the second gear (second speed counter gear) 2c increases, and the relative rotation direction of the second gear 2c viewed from the first key 1k and the second key 2k is the direction of arrow D in FIG. 6 (c1). Thus, the trailing surface 2dr of the second dog 2d is separated from the trailing claw 1kr of the first key 1k. Thereby, the transmission of torque in the second speed state by the first key 1k is completed. The first key 1k separated from the second dog 2d is moved to the first gear 1c side by the return force of the first detent mechanism 1det, and therefore does not interfere with the second dog 2d.

  As described above, when shifting from the second speed to the first speed during engine deceleration, the first shift fork 1f and the second shift fork 2f are respectively connected to the first detent mechanism 1det and the second detent mechanism 2det. The connected shift rod 11 is moved from the second gear 2c side to the first gear 1c side. Then, with the first key 1k transmitting torque in the second speed state engaged with the second dog 2d, only the torque-free second key 2k is moved to the first gear 1c side and the first dog 1d. Can be shifted down without running out of torque. That is, when shifting down during deceleration, only the single shift rod 11 connecting the first shift fork 1f and the second shift fork 2f is moved in the axial direction from the second gear 2c side to the first gear 1c side. As a result, the movement control of the shift rod 11 and the operation system structure can be simplified. The movement of the shift rod 11 is the same as that in the case of downshifting of a normal manual transmission.

(Modification)
A modification of the first and second groove portions 1g and 2g constituting the first and second detent mechanisms 1det and 2det will be described with reference to FIG. FIG. 7 shows only the first groove 1g of the first detent mechanism 1det, but the second groove 2g of the second detent mechanism 2det has the same configuration, and thus the description of the second groove 2g is omitted. To do. The first groove 1g in the modified example aims to optimize the detent load (return force of the first shift fork 1f) with respect to the detent operation amount (movement amount of the first shift fork 1f from the initial position) of the first detent mechanism 1det. It is a thing.

  As shown in FIG. 7, the first groove portion 100g formed in the shift rod 11 is steeply inclined with the steeply inclined portion 1ga with which the first ball 1b abuts when the first shift fork 1f with respect to the shift rod 11 is in the initial position. And a gently inclined portion 1gb formed to be connected to the portion 1ga. The gently inclined portion 1gb has a smaller inclination angle than the steeply inclined portion 1ga. FIG. 7A shows a state where the ball 1b is disposed at the steeply inclined portion 1ga at the initial position, and FIG. 7B shows a state where the ball 1b is displaced from the initial position and disposed at the gently inclined portion 1gb. .

  In FIG. 7, F1 and F2 are spring loads of the first spring 1xb (see FIG. 4A), Fa1 and Fa2 are vertical forces of the spring load against the steeply inclined portion 1ga or the gently inclined portion 1gb, and Fb1 and Fb2 are vertical. Of the force, the axial force of the shift rod 11 at the steeply inclined portion 1ga or the gently inclined portion 1gb (this force becomes the return force), Fc1 and Fc2 are the shift rods at the steeply inclined portion 1ga or the gently inclined portion 1gb of the vertical force 11 radial force. According to this configuration, as shown in FIG. 7 (b), the ball 1b is displaced from the initial position, and the compression length of the first spring 1xb shown in FIG. 4 (a) is increased, and the ball 1b is pressed against the groove 1g. Even if the force (spring load F2) increases, the axial return force Fb2 does not increase due to the force decomposition by the gently inclined portion 1gb.

  As described above, since the return force of the first detent mechanism 1det does not increase even when the first detent mechanism 1det deviates from the initial position, in the power-on shift with the low driving torque, when the shift from FIG. 5 (a1) to FIG. On-shift up), or when shifting the shift rod 11 in the axial direction when shifting from FIG. 6 (a1) to FIG. 6 (b1) (power-on shift-down), the first dog 1d and the second dog 2d It is possible to prevent the first key 1k and the second key 2k from coming off by the return force by overcoming the reverse taper of the leading surfaces 1df and 2df and the trailing surfaces 1dr and 2dr. As a result, it is possible to avoid torque loss during power-on shifting with low drive torque.

  In addition, if the inclination angle of the steeply inclined portion 1ga of the first groove portion 1g is made larger, a high holding force can be secured at the initial position where the operation amount of the first detent mechanism 1det is zero. Thus, the movement of the first shift fork 1f due to the inertia after returning from the operating state to the initial position can be suppressed while restricting the movement of the first shift fork 1f against the meaning of the disturbance at the initial position. The same applies to the second groove 2g. In addition, the gentle inclination part 1gb of the 1st groove part 1g may have a several inclination angle instead of one inclination angle. In this case, the gently inclined portion 1gb has a characteristic that the inclination angle gradually decreases as the distance from the initial position increases. Further, the gently inclined portion 1gb may have a curved surface or arc shape having similar characteristics.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various modifications within the scope of the claims. Needless to say, examples and modifications also belong to the technical scope of the present invention. For example, the first gear and the second gear may be mounted on the main shaft (input shaft) instead of the counter shaft (output shaft) of the transmission.

  The present invention can be used in a transmission that prevents torque loss during gear shifting.

1 Transmission 5 Shaft (Counter shaft)
1c 1st gear (1st counter gear)
2c Second gear (2-speed counter gear)
1d 1st dog 1df leading surface 1dr trailing surface 2d 2nd dog 2df leading surface 2dr trailing surface 1s first sleeve ring 1k first key 1kf leading claw 1kr trailing claw 2s second sleeve ring 2k second key 2kf leading claw 2kr trailing claw 1f first shift fork 1fb first insertion part 2f second shift fork 2fb second insertion part 11 shift rod 12 holding mechanism 1det first detent mechanism 1g first groove 1b first ball 1x first biasing means 2det 2nd detent mechanism 2g 2nd groove part 2b 2nd ball 2x 2nd urging means 1ga Steeply inclined part 1gb Slowly inclined part

Claims (5)

A first gear rotatably mounted on a shaft and having a first dog projecting from a side surface;
A second gear rotatably mounted on the shaft and having a second dog projecting on a side surface;
Between the second gear and the first gear, the shaft rotates integrally with the shaft and is movable in the axial direction of the shaft. One end engages with the leading surface of the first dog and the other end A first sleeve ring having a first key that engages a trailing surface of the second dog;
Between the second gear and the first gear, the shaft rotates integrally with the shaft and is movable in the axial direction of the shaft. One end engages with the trailing surface of the first dog and the other. A second sleeve ring having a second key whose end engages the leading surface of the second dog;
A first shift fork engaged with the first sleeve ring;
A second shift fork engaged with the second sleeve ring;
A shift rod connected to the first shift fork and the second shift fork and moved in the axial direction in conjunction with a shift operation;
A holding mechanism provided between the shift rod and the first shift fork and the second shift fork,
The holding mechanism holds the positions of the first shift fork and the second shift fork with respect to the shift rod at an initial position, and the first key and the second key are engaged with the first dog and the second dog. A transmission that allows movement of the shift rod in a state and exhibits a return force for returning the first shift fork and the second shift fork to their initial positions. The first key has a leading claw that engages the leading surface of the first dog at one end, and a trailing claw that engages the trailing surface of the second dog at the other end,
The second key has a trailing claw that engages the trailing surface of the first dog at one end and a leading claw that engages the leading surface of the second dog at the other end,
Each leading surface and trailing surface of the first dog and the second dog are formed in a reverse taper shape so as to spread from the root toward the tip,
Each leading claw and trailing claw of the first key and the second key are formed in a reverse taper shape so as to engage with each leading surface and trailing surface,
The return force of the holding mechanism is set to be weaker than the engaging force due to the reverse taper when the leading pawls and trailing pawls are engaged with the leading and trailing surfaces during shifting. The transmission according to claim 1. The first shift fork has a first insertion portion through which the shift rod is inserted so as to be movable in the axial direction;
The second shift fork has a second insertion portion through which the shift rod is inserted so as to be movable in the axial direction.
The holding mechanism includes a first detent mechanism provided between the first insertion part and the shift rod, and a second detent mechanism provided between the second insertion part and the shift rod. The transmission according to claim 1 or 2, wherein The first detent mechanism includes:
A first groove portion formed along the axial direction in a shift rod inserted through the first insertion portion and having a center along the axial direction deeper than both ends;
A first ball or a first roller disposed in the first groove,
First urging means for pressing the first ball or the first roller against the first groove,
The second detent mechanism is:
A shift rod inserted into the second insertion portion, formed along the axial direction, and a second groove portion whose center along the axial direction is deeper than both ends;
A second ball or a second roller disposed in the second groove,
The transmission according to claim 3, further comprising: a second urging unit that presses the second ball or the second roller against the second groove portion. The first groove portion includes a steeply inclined portion with which the first ball or the first roller abuts when the first insertion portion with respect to the shift rod is in an initial position, and a gently inclined portion formed to be connected to the steeply inclined portion. And
The second groove portion includes a steeply inclined portion where the second ball or the second roller abuts when the second insertion portion with respect to the shift rod is in an initial position, and a gently inclined portion formed by being connected to the steeply inclined portion. The transmission according to claim 4, further comprising:

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