JP2007056994A - Shift device of transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission shift device in a simple structure and with a casing made compact. <P>SOLUTION: This shift device S for selectively switching plural pairs of transmission gears mounted on a pair of transmission gear shafts 11, 12 and engaged with each other, comprises shift forks 22, 23 movably guided and supported in parallel with the transmission gear shafts and provided with follower pins 22b, 23b radially projecting, and a cam plate 25 having the shape of circular arc face of a large radius or a planar plate along an inner face of the casing 10, guided and supported movably in the direction orthogonal to the moving direction of the shift forks, and provided with cam grooves 26, 27 with which the follower pins are slidably engaged along the moving direction. The cam plate 25 is moved by a driving mechanism 30, thus the shift forks are moved to selectively switch the plural pairs of transmission gears. One or plural cam grooves and shift forks may be used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shift device for a transmission that performs a gear shift of a selection gear type transmission used in an automobile or the like.

  As a shift device of this type of transmission, there are one that performs gear shift by two-direction movement (axial movement and rotation) of selection and shift, and one that performs gear shift only by one-direction movement (rotation). . For example, as shown in Patent Document 1, the former has a plurality of fork shafts that perform gear shifting via a shift fork, and selects one fork shaft by axial movement of the shift and select shaft, and then shift and select shaft. The gear shift is performed by moving the fork shaft and the shift fork by the rotation. The latter includes, for example, a plurality of shift forks slidably supported on a fork shaft and a cylindrical shift drum having a plurality of cam grooves formed on the outer peripheral surface, as shown in Patent Document 2, for example. A gear shift is performed by moving each shift fork engaged with each cam groove by rotating the shift drum.

Both of these techniques can be applied to either a case where the gear shift is manually performed or a case where the gear shift is automatically performed using an actuator such as a motor controlled based on a shift command corresponding to an operation state of an automobile or the like. .
JP 2004-308678 A (paragraphs [0030] to [0031], FIG. 1 and FIG. 2). Japanese Patent Application Laid-Open No. 07-139627 (paragraphs [0019] to [0025], FIGS. 1 to 4).

  In the technique of Patent Document 1, since the gear shift is performed by the axial movement and rotation of the shift and select shaft, there is a problem that the number of parts increases and the structure becomes complicated, especially when the gear shift is automatically performed. Since two actuators are required, the manufacturing cost increases. On the other hand, in the technique of Patent Document 2, since only the shift drum is rotated, the number of parts is relatively small, the structure is simple, and the manufacturing cost is reduced as compared with the technique of Patent Document 1.

  FIG. 7 shows an example of the prior art in which the gear shift is automatically performed using a servo motor in the technique shown in Patent Document 2. In this prior art, two shift forks 3a and 3b supported on a casing 1 so as to be movable on a fork shaft 2 provided in parallel with a transmission gear shaft, and a shaft 7 on the upper side of the fork shaft 2 are rotatably supported. The shift fork 3a, 3b includes a shift device including a shift drum 4 having cam grooves 4a, 4b formed on the outer periphery and a servo motor 8 that rotates the shift drum 4 via a speed reduction mechanism including gears 5, 6. The transmission gears are selectively switched by slidably engaging the follower pins 3c and 3d provided on the cam grooves 4a and 4b. In this structure, the shift drum 4 having a considerable thickness largely protrudes above the shift forks 3a and 3b, so that there is a problem that the casing 1 greatly protrudes locally and the transmission becomes large. When gear shifting is automatically performed as described above, the servomotor 8 and the speed reduction mechanisms 5 and 6 also project outside the shift forks 3a and 3b, so that the transmission is further increased in size.

  It is an object of the present invention to provide a shift device for a transmission that solves each of the above problems and has a simple structure and allows a casing to be miniaturized.

  To this end, a transmission shift device according to the present invention includes a plurality of pairs of transmission gears that are provided on a pair of transmission gear shafts that are rotatably supported in a casing and mesh with each other. In a shift device for a transmission that selectively switches so that power is transmitted between both transmission gear shafts, a follower pin that is guided and supported so as to be movable parallel to each transmission gear shaft and that projects in a direction orthogonal to the moving direction And a shift fork formed on the casing in a direction perpendicular to the moving direction of the shift fork in the direction along the plate surface in the shape of a circular arc or planar plate having a large radius along the inner surface of the casing. A cam plate having a cam groove in which a guide groove is supported and a follower pin is slidably engaged along a moving direction thereof, and the cam plate is changed in accordance with a shift command. A drive mechanism that moves in a moving direction is provided, and a shift fork is moved through a cam groove and a follower pin that are engaged with each other by movement of a cam plate by the drive mechanism, and multiple pairs of transmission gears are selectively switched. It is characterized by.

  In the transmission shift device described in the preceding paragraph, it is preferable that a plurality of shift forks be provided, and a cam plate be formed with a plurality of cam grooves into which the follower pins of the respective shift forks are respectively engaged.

  In the transmission shift device described in the preceding item 2, the drive mechanism may move the cam plate by a motor controlled based on a shift command.

  In the transmission shift device described in the preceding paragraph, the cam plate has a circular arc shape, and the drive mechanism is rotated by a sector worm wheel formed on the outer surface of the cam plate along the moving direction and meshed with the sector worm wheel. The cam plate may be made of a worm that moves the cam plate.

  Further, in the transmission shift device described in the preceding paragraph, the cam plate is planar, and the drive mechanism is rotationally driven by a nut and a motor fixed to the cam plate 25 and screw-engaged with the nut to move the cam plate. It may be formed of a screw shaft.

  In the shift device for a transmission described in the preceding items, it is preferable that an annular member that is in rolling contact with the cam groove is provided coaxially on the follower pin.

  As described above, according to the present invention, the cam plate in which the cam groove in which the follower pin of the shift fork is slidably engaged is formed is an arcuate or planar plate having a large radius along the inner surface of the casing. If the gap between the shift fork and the casing is slightly larger than the thickness of the cam plate, it is supported by the casing so as to be movable in the direction perpendicular to the movement direction of the shift fork in the direction along the plate surface. A cam plate can be arranged. Therefore, since it is not necessary to greatly separate the casing from the shift fork, the casing of the transmission is reduced in size, so that the transmission can be reduced in size.

  According to the shift device for a transmission in which a plurality of shift forks are provided and the cam plate is formed with a plurality of cam grooves into which the follower pins of the respective shift forks are respectively engaged, the shift fork and the cam remain with only one cam plate. Since the number of gears of the transmission can be increased simply by increasing the number of grooves, the structure is not complicated and the weight is not increased even if the number of gears is increased.

  According to the transmission shift device in which the drive mechanism moves the cam plate by the motor controlled based on the shift command, the transmission can be automatically controlled according to the operating state.

  The cam plate has a circular arc surface, and the drive mechanism is composed of a sector worm wheel formed on the outer surface of the cam plate along the moving direction and a worm that is driven to rotate by a motor and meshes with the sector worm wheel to move the cam plate. According to the shift device of the transmission, the cam plate is moved with the motor rotation being sufficiently decelerated and transmitted by the worm and sector worm wheel, and a special speed reduction mechanism is not required. Can be reduced. Further, the amount of protrusion of the drive mechanism from the cam plate is small compared to the shift drum in the prior art shown in FIG. 7, and the amount of local protrusion of the casing accompanying this is also small. Kept.

  In addition, the shift mechanism of the transmission has a flat cam plate, and a drive mechanism is composed of a nut fixed to the cam plate and a screw shaft that is rotationally driven by a motor and screw-engaged with the nut to move the cam plate. The rotation of the motor is transmitted to the cam plate while being sufficiently decelerated by the screw shaft and the nut, and a special decelerating mechanism is not required. Therefore, the structure can be simplified and the manufacturing cost can be reduced. Also in this case, the amount of protrusion of the drive mechanism from the cam plate is small compared to the shift drum in the prior art shown in FIG. 7, and the amount of local protrusion of the casing accompanying this is also small. Miniaturization is maintained.

  According to the transmission shift device in which the follower pin is coaxially provided with an annular member that is in rolling contact with the cam groove, the friction resistance between the follower pin of the shift fork and the cam groove of the cam plate is reduced. Accordingly, the radius of the plate-like cam member that is curved in the shape of an arc surface can be reduced, so that the shift device of the transmission can be made more compact.

  First, a first embodiment of a shift apparatus for a transmission according to the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a transmission of an automobile, and is provided on a pair of transmission gear shafts 11 and 12 supported in a casing 10 and meshes with each other as in the overall structure shown in FIG. A plurality of pairs of transmission gears 13a to 16a and 13b to 16b are selectively switched by a shift device S so that power is transmitted between the transmission gear shafts 11 and 12 by any one of them. .

  As shown in FIG. 1, an input shaft 11 connected to an engine and driven to rotate and a main shaft 12 connected to a driving wheel of an automobile are parallel to each other via a rolling bearing. The input shaft 11 and the main shaft 12 constitute a pair of transmission gear shafts 11 and 12. In the transmission chamber formed in the casing 10, four drive-side transmission gears 13a to 16a that are rotatably provided on the input shaft 11 and the transmission gear 13a are provided so as to rotate integrally with the main shaft 12. Four driven side transmission gears 13b to 16b that are always meshed with .about.16a are located. The pair of transmission gears 13a and 13b, the transmission gears 14a and 14b, the transmission gears 15a and 15b, and the transmission gears 16a and 16b, which mesh with each other, are respectively the first speed, the second speed, the third speed, and the fourth speed. A gear pair is formed.

  In the first embodiment, the input shaft 11 is integrally provided with clutch hubs 11a and 11b between the transmission gears 13a and 14a and between the transmission gears 15a and 16a. The switching sleeves 17 and 18 are spline-engaged so as to be slidable in the axial direction. The transmission gears 13a, 14a and the transmission gears 15a, 16a are formed with splines that can be engaged with the switching sleeves 17, 18 at boss portions formed on the clutch hubs 11a, 11b side, respectively. On the outer periphery of the switching sleeves 17 and 18, annular grooves 17a and 18a for engaging the shift forks 22 and 23 of the shift device S are formed. Although not shown, a known synchromesh mechanism is provided between the switching sleeves 17 and 18 and the transmission gears 13a to 16a.

  FIG. 1 shows a neutral state of the transmission in which the switching sleeves 17 and 18 are engaged only with the clutch hubs 11a and 11b and no power is transmitted between the transmission gear shafts 11 and 12, which will be described later. If the switching sleeves 17 and 18 are reciprocated by the shift device S, any one of the transmission gears 13a to 16a is selectively connected to the input shaft 11 via the switching sleeves 17 and 18, and the first Power is transmitted by each speed stage from the fourth speed to the fourth speed.

  As shown in FIGS. 1 and 2, the shift device S of the first embodiment includes one fork shaft 20 supported by the casing 10 in parallel with the two transmission gear shafts 11 and 12, and the fork shaft 20. Both positions indicated by a two-dot chain line 25A and a two-dot chain line 25B in a plate-like direction perpendicular to the moving direction of the shift forks 22, 23, which are slidably guided and supported. And a drive mechanism 30 that moves the cam plate 25 in the moving direction in accordance with a shift command, and is formed along the moving direction of the cam plate 25. The follower pins 22b and 23b protruding from the first and second shift forks 22 and 23 are slidably engaged with the first and second cam grooves 26 and 27. The cam plate 25 is moved and stopped by the drive mechanism 30 in accordance with a shift command as will be described later.

  As shown in FIGS. 1 to 3, the first and second shift forks 22 and 23 are slidably guided and supported by the fork shaft 20 by boss portions 22 a and 22 b, and are formed on the outer circumferences of the switching sleeves 17 and 18. It has a bifurcated portion engaged with the annular grooves 17a, 18a. In each shift fork 22, 23, the boss portions 22a, 23b are pivoted around the fork shaft 20, but each tip portion of the bifurcated portion is on both sides in the diameter direction of the annular grooves 17a, 18a of the switching sleeves 17, 18 Therefore, the rotation with respect to the casing 10 is restricted. Each boss portion 22a, 22b is provided with a follower pin 22b, 22c projecting in the radial direction on the opposite side to the bifurcated portion.

  As shown in FIGS. 1 to 3, the cam plate 25 of the first embodiment is curved in a circular arc shape having a large radius in the direction along the moving direction, and the cross section in the direction along the fork shaft 20. Is a straight plate, and is disposed between the inner surface of the casing 10 and the boss portions 22a and 22b of the shift forks 22 and 23 so that the outer surface faces the casing 10 side. The cam plate 25 slidably guides two short pins 25 a protruding from both end faces in the axial direction of the fork shaft 20 into an arcuate guide groove 10 a formed on the inner end face of the casing 10 and having a large radius. By being supported, it is guided and supported so as to be movable along the inner surface of the casing 10 in a direction perpendicular to the moving direction of the shift forks 22, 23, that is, along a curved plate surface.

  As shown in FIG. 3, the follower pins 22b and 23b of the shift forks 22 and 23 are slidably engaged with the cam plate 25 with a slight gap along the moving direction perpendicular to the fork shaft 20. First and second cam grooves 26 and 27 are formed. The cam plate 25 has seven positions centered on the center line CL in the moving direction-first speed position 1st, neutral position N1, second speed position 2nd, neutral position N2, third speed position 3rd, and neutral position N3. The fourth speed position 4th- is set, and the neutral position N2 coincides with the center line CL.

  The first cam groove 26 includes a shift groove 26a formed of a three-quarter cycle waveform portion connecting between the neutral position N2 and the first speed position 1st, and a fork shaft connecting between the neutral position N2 and the fourth speed position 4th. 20, and a peak portion and a valley portion (in a state where the right side in the figure is the lower side) of the wavy shift groove 26 a are respectively set to a first speed position 1st and a second speed position 2nd. positioned. The second cam groove 27 is a quadrant connecting the neutral position N2 perpendicular to the fork shaft 20 connecting between the neutral position N2 and the first speed position 1st and between the neutral position N2 and the fourth speed position 4th. The crest and trough (in the same state as above) of the wavy shift groove 27b are located at the third speed position 3rd and the fourth speed position 4th, respectively. . First, neutral, second, and neutral positions 1st, N1, 2nd, and N2 of the shift groove 26a, and neutral, third, neutral, and fourth positions N2, 3rd, and N3 of the shift groove 27b, respectively. , 4th is formed with a short straight portion perpendicular to the fork shaft 20.

  The drive mechanism 30 includes a sector worm wheel 32 integrally formed on the outer surface of the arc-shaped cam plate 25 along a center line orthogonal to the fork shaft 20, and a distal end portion of a worm shaft 31 a orthogonal to the fork shaft 20. A worm 31 that is integrally provided and meshes with the sector worm wheel 32, and a servomotor 33 that rotationally drives the worm shaft 31a. The servo motor 33 of the drive mechanism 30 is controlled based on a shift command output from a control device (not shown) according to the operating state of an automobile or the like. The worm 31 is rotated by the servo motor 33, The cam plate 25 is moved in the arc direction via the sector worm wheel 32, and each position between the first speed to the fourth speed 1st to 4th and between the first speed position 1st and the second speed position 2nd according to the shift command. The neutral position N1 is stopped at each position directly above the fork shaft 20. The drive mechanism 30 is not limited to one set, and two sets or more may be used.

  Next, the operation of the above-described first embodiment will be described with reference to FIG. In the neutral state, as shown in FIG. 6 (a), the cam plate 25 is positioned at the neutral position N1 directly above the fork shaft 20 by the drive mechanism 30, and both the shift forks 22 and 23 have their follower pins 22b, 23b is in the neutral position of the fork engaged with the shift groove 26a and the neutral groove 27a of each cam groove 26, 27 at the neutral position N1, so that each switching sleeve 17, 18 has a clutch hub 11a, It is in the neutral position engaged only by 11b. In this state, since each of the transmission gears 13a to 16a is rotatable with respect to the input shaft 11, the transmission is in a neutral state in which power transmission between the transmission gear shafts 11 and 12 is not performed.

  If the cam plate 25 is moved by the drive mechanism 30 from this neutral state, the first speed position 1st on the most end side is set to a position indicated by a two-dot chain line 25A that is directly above the fork shaft 20 (FIG. 6B). As shown in FIG. 6 (b), the follower pin 22b of the first shift fork 22 is slid to the crest at the tip of the shift groove 26a of the first cam groove 26 and moved leftward from the first fork neutral position. It is moved to the first fork shift position. As a result, the switching sleeve 17 is moved to the left from its neutral position, so that the transmission gear 13a is connected to the input shaft 11 via the switching sleeve 17, but the transmission gear 14a remains rotatable with respect to the input shaft 11. is there. On the other hand, since the follower pin 23b of the second shift fork 23 is engaged with the tip of the neutral groove 27a of the second cam groove 27 and does not move from the second fork neutral position, both the transmission gears 15a and 16a are input. It remains free to rotate with respect to the shaft 11. In this state, the transmission is in a first speed state in which power is transmitted to both transmission gear shafts 11 and 12 by transmission gears 13a and 13b forming a first speed gear pair.

  If the cam plate 25 is returned from the first speed state by the drive mechanism 30 beyond the neutral position N1 so that the second speed position 2nd is directly above the fork shaft 20 (see FIG. 6B). The first shift fork 22 has its follower pin 22b slid in the valley of the shift groove 26a, moved rightward beyond the first fork neutral position, and moved to the first fork shift position shown in FIG. 6 (b). . As a result, the switching sleeve 17 is moved to the right from the neutral position, so that the transmission gear 14a is connected to the input shaft 11 via the switching sleeve 17, and the transmission gear 13a is rotatable with respect to the input shaft 11. On the other hand, since the follower pin 23b of the second shift fork 23 is engaged with the neutral groove 27a, both the transmission gears 15a and 16a remain rotatable with respect to the input shaft 11 as in the first speed state. In this state, the transmission is in the second speed state in which power is transmitted to both the transmission gear shafts 11 and 12 by the transmission gears 14a and 14b forming the second speed gear pair.

  If the cam plate 25 is further moved from the second speed state by the drive mechanism 30 so that the third speed position 3rd is directly above the fork shaft 20 (see FIG. 6 (c)), the second shift fork 23, the follower pin 23b is slid on the peak portion of the shift groove 27b of the second cam groove 27, moved to the left from the second fork neutral position, and moved to the second fork shift position shown in FIG. 6 (c). The As a result, the switching sleeve 18 is moved leftward from its neutral position, so that the transmission gear 15a is connected to the input shaft 11 via the switching sleeve 17, but the transmission gear 16a remains rotatable with respect to the input shaft 11. is there. On the other hand, since the first shift fork 22 has its follower pin 22b engaged with the neutral groove 27a of the second cam groove 27 and the switching sleeve 17 is in the neutral position, both the transmission gears 13a and 14a rotate with respect to the input shaft 11. Be free. In this state, the transmission is in a third speed state in which power is transmitted to both transmission gear shafts 11 and 12 by transmission gears 15a and 15b forming a third speed gear pair.

  Further, if the cam plate 25 is further moved by the drive mechanism 30 from the third speed state, the fourth speed position 4th is set to a position indicated by a two-dot chain line 25B that is directly above the fork shaft 20 (FIG. 6D). The second shift fork 23 has its follower pin 23b slid in the trough at the tip of the shift groove 27b and moved to the right beyond the neutral position of the second fork, as shown in FIG. 6 (b). Moved to position. As a result, the switching sleeve 18 is moved to the right from the neutral position, so that the transmission gear 16a is connected to the input shaft 11 via the switching sleeve 18, and the transmission gear 15a is rotatable with respect to the input shaft 11. On the other hand, since the follower pin 22b of the first shift fork 22 is engaged with the tip of the neutral groove 27a, both the transmission gears 13a and 14a remain rotatable with respect to the input shaft 11 as in the third speed state. It is. In this state, the transmission is in a fourth speed state in which power is transmitted to both the transmission gear shafts 11 and 12 by the transmission gears 16a and 16b forming the fourth speed gear pair.

  In the first embodiment, short linear portions orthogonal to the fork shaft 20 are provided at the positions 1st, N1, 2nd, N2 of the shift groove 26a and the positions N2, 3rd, N3, 4th of the shift groove 27b. In this way, even if the cam plate 25 stops slightly out of position, the shift positions of the shift forks 22 and 23 are less misaligned. However, this short straight portion can be omitted.

  According to the first embodiment described above, the cam plates 25 for moving the shift forks 22 and 23 are formed along the inner surface of the casing 10 by forming the cam grooves 26 and 27 in which the follower pins 22b and 23b are slidably engaged. Since the plate has a circular arc shape with a large radius and is guided and supported by the casing 10 so as to be movable in a direction perpendicular to the moving direction of the shift fork in the direction along the plate surface, the shift forks 22 and 23 and the casing 10 are supported. If there is a gap slightly larger than the thickness of the cam plate 25, the cam plate 25 can be disposed. Therefore, since it is not necessary to largely separate the casing 10 from the shift forks 22 and 23, the casing 10 of the transmission can be downsized, and the transmission can be downsized.

  In this type of transmission, two shift speeds can be obtained by one shift fork, and the number of shift speeds is increased by increasing the number of shift forks. However, if the number of shift forks is increased, the number of parts associated therewith is increased. It is normal to increase. However, in the first embodiment described above, the number of shift stages of the transmission is increased by increasing the number of cam grooves 26 and 27 formed with one cam plate 25 and increasing the number of shift forks 22 and 23. Therefore, even if the number of gears is increased, the structure is not so complicated and the weight is not increased. It should be noted that the number of shift forks is not limited to two and can be increased. However, the present invention is not limited to these, and can be applied to the case where there is one shift fork. Even in such a case, the effects described in the previous section can be obtained.

  In the first embodiment described above, the cam plate 25 has a circular arc shape, and is provided at the tip of the worm shaft 31a driven by the servomotor 33 on the sector worm wheel 32 formed on the outer surface of the cam plate 25 along the moving direction. The worm 31 meshes and moves. By doing so, the rotation of the servo motor 33 is sufficiently decelerated to move the cam plate 25, and a special speed reduction mechanism is unnecessary, thus simplifying the structure. Manufacturing costs can be reduced. Further, the sector worm wheel 32 and the thin worm 31 having a low height protrude from the cam plate 25, and the amount of protrusion is small compared to the shift drum 4 in the prior art shown in FIG. Since the amount of local protrusion of the casing 10 is also small, the transmission can be kept small.

  However, the present invention is not limited to this, and, as in the second embodiment shown in FIG. 4, the cam plate 25 has a planar shape and is driven to rotate by a servo motor 33 on a nut 34 fixed to the center of the upper surface. Then, the cam plate 25 may be moved by screw-engaging the nut 34. Even in this case, the rotation of the servo motor 33 is sufficiently decelerated to move the cam plate 25, and a special decelerating mechanism is unnecessary, so that the structure can be simplified and the manufacturing cost can be reduced. Projecting from 25 is a nut 34 having a low height and a screw shaft 35 that is screw-engaged with the nut 34, and the projecting amount thereof is small as in the first embodiment described above, so that the transmission can be kept downsized. be able to. In the second embodiment shown in FIG. 4, the cam plate 25 is made flat in the casing 10 except that the cam plate 25 is planar and the cam plate 25 is moved by the servo motor 33 via the nut 34 and the screw shaft 35. Since it is the same as that of 1st Embodiment mentioned above including the point arrange | positioned between the inner surface and the boss | hub parts 22a and 22b of the shift forks 22 and 23, only the same part attaches | subjects and shows the same code | symbol as detailed. Description is omitted.

  In each of the embodiments described above, the follower pins 22b and 23b provided so as to protrude from the shift forks 22 and 23 are simple rods. However, as in the modification shown in FIG. 5, the follower pins 22b and 23b have a shift fork at the base. Rollers engaged rotatably with a main body 21a that is fixed to the bosses 22a and 23b of 22 and 23 by press-fitting or the like and protrudes in the radial direction, and a small-diameter portion 21b that is coaxially formed at the tip of the main body 21a. An annular member) 21c may be used. The roller 21c has a slightly larger diameter than the main body portion 21a, and is rotatably prevented by a washer 21d that is caulked and fixed to the tip of the small diameter portion 21b. When the follower pins 22b and 23b of this modified example are inserted into the cam grooves 26 and 27, the outer peripheral surfaces of the rollers 21c are brought into rolling contact with the inner surfaces of the cam grooves 26 and 27, respectively. If each roller 21c is in rolling contact with the cam grooves 26 and 27 in this way, the frictional resistance between the follower pins 22b and 23b and the cam grooves 24 and 25 is reduced, so that the operation of the shift device S can be lightened.

  If the length of the cam plate 25 in the moving direction is shortened to reduce the size of the shift device S, the angle of the inclined portions of the shift grooves 26a and 27b of the cam grooves 26 and 27 with respect to the moving direction becomes steep, and the follower pin The friction resistance between 22b and 23b and the cam grooves 24 and 25 increases, and the movement of the cam plate 25 may become unsmooth. However, if the follower pins 22b and 23b shown in FIG. 5 are used, the frictional resistance is reduced. Therefore, the shift device S can be reduced by shortening the length of the cam plate 25 in the moving direction without fear of unsmooth movement of the cam plate 25. Can be miniaturized. If a miniature bearing is used instead of the roller 21c, the frictional resistance between the drive pin and the cam groove is further reduced, so that the operation of the shift device can be further reduced and the shift device can be made more compact. When the miniature bearing is used, the outer ring becomes an annular member 21c that is in rolling contact with the cam grooves 24 and 25. If such an annular member is also provided on the pin 25a that guides and supports the cam plate 25, the operation of the shift device S is further lightened.

  In the embodiment described above, the two switching sleeves 17 and 18 are both provided on the input shaft 11, and the shifting sleeves 17 and 18 are moved by the shift forks 22 and 23, and the transmission gears 13 a to 16 a provided on both sides thereof are provided. The input shaft 11 is selectively connected to the input shaft 11. However, the input shaft 11 and the main shaft 12 are each provided with one switching sleeve, and each switching fork is moved by each shift fork so as to be rotatably provided on both sides thereof. The gear may be selectively connected to the input shaft 11 or the main shaft 12. Further, the transmission gear train is of a constantly meshing type in which the gear stage is switched by a switching sleeve, but is not limited to this, and other types of constantly meshing type gears or shifting gears are moved to change the gear stage. A sliding selection type that performs switching may be used.

  In the above-described embodiment, the case where the four shift speeds are the first speed to the fourth speed has been described, but it is also possible to set the reverse speed and the four shift speeds of the first speed to the third speed. In that case, the gear pairs may be arranged in reverse order and in order of the first speed to the third speed. By doing so, each shift position including the neutral position N is arranged in the order of the reverse drive position, the neutral position N, the first speed position 1st to the third speed position 3rd. The reverse gear pair provided on the transmission gear shafts 11 and 12 is meshed via an idle gear instead of meshing directly.

  The present invention also provides a second transmission gear comprising a transmission gear of a high speed stage of the fifth speed (or fourth speed) or higher between the transmission gear shafts 11 and 12 in parallel with the transmission gears 13a to 16a and 13b to 16b. It is also possible to carry out such a manner that this transmission gear is switched by a shift device provided with a row and provided with one or more shift forks similar to the shift device S. In the case of such a transmission, the second transmission gear train is switched while the first transmission gear train is sequentially switched from the first speed state to the fourth speed state (or from the reverse state to the third speed state) as described above. Is in a neutral state, the first transmission gear train is in a neutral position N3 between the third speed position 3rd and the fourth speed position 4th, and the second transmission gear train is moved to the fifth speed by the shift device. (Or 4th speed) Switch to a higher speed or higher.

  In the above-described embodiment, the cam plate 25 is moved by the drive mechanism 30 that is controlled based on the shift command. In this way, the transmission is automatically set according to the operating state of the automobile. Can be controlled. However, the present invention is not limited to this, and can be applied to a manual transmission.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing an overall structure including a transmission of a first embodiment of a transmission shift device according to the present invention. It is 2-2 sectional drawing of FIG. It is a top view of the shift apparatus of embodiment shown in FIG. FIG. 3 is a cross-sectional view corresponding to FIG. 2 of a second embodiment of the transmission shift device according to the present invention. It is a side view which shows the modification of a follower pin inserted in a cam groove. It is a top view explaining the action | operation of the shift apparatus of the transmission by this invention. It is front sectional drawing which shows the whole structure of the shift apparatus of the transmission by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Casing, 11, 12 ... Transmission gear shaft (input shaft, main shaft), 13a-16a, 13b-16b ... Transmission gear, 21c ... Annular member (roller), 22, 23 ... Shift fork, 22b, 23b ... Follower pin, 25 ... cam plate, 26, 27 ... cam groove, 30 ... drive mechanism, 31 ... worm, 32 ... sector worm wheel, 33 ... servo (servo motor), 34 ... nut, 35 ... screw shaft.

Claims (6)

  A plurality of pairs of transmission gears which are provided on a pair of transmission gear shafts rotatably supported in the casing and mesh with each other so that power is transmitted between the two transmission gear shafts by any one of them. A shift fork having a follower pin that is guided and supported so as to be movable in parallel with each of the transmission gear shafts and protrudes in a direction orthogonal to the movement direction; and an inner surface of the casing. An arcuate or flat plate shape with a large radius along the guide surface is guided and supported by the casing so as to be movable in a direction perpendicular to the moving direction of the shift fork in the direction along the plate surface along the moving direction. A cam plate formed with a cam groove in which the follower pin is slidably engaged, and a drive for moving the cam plate in the moving direction in accordance with a shift command. The shift fork is moved through the cam groove and the follower pin engaged with each other by the movement of the cam plate by the drive mechanism, and the plurality of pairs of the transmission gears are selectively switched. A shift device for a transmission.   2. The shift device for a transmission according to claim 1, wherein the shift fork includes a plurality of shift forks, and the cam plate includes a plurality of cam grooves into which the follower pins of the shift forks are respectively engaged. Shift device for transmission.   3. The transmission shift apparatus according to claim 1, wherein the drive mechanism moves the cam plate by a motor controlled based on a shift command.   4. The transmission shift device according to claim 3, wherein the cam plate has an arcuate surface shape, and the drive mechanism is rotationally driven by a sector worm wheel formed on the outer surface of the cam plate along a moving direction and the motor. A shift device for a transmission comprising a worm that meshes with the sector worm wheel to move the cam plate.   4. The shift device for a transmission according to claim 3, wherein the cam plate has a planar shape, and the drive mechanism is rotationally driven by a nut fixed to the cam plate and the motor and is screw-engaged with the nut. A shift device for a transmission comprising a screw shaft for moving a plate. The transmission shift device according to any one of claims 1 to 5, wherein the follower pin is coaxially provided with an annular member that is in rolling contact with the cam groove. apparatus.

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