JP2006292144A - Reverse fit preventing structure for asymmetric sleeve of switching clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an asymmetric sleeve for a switching clutch from being reversely fit by mistake. <P>SOLUTION: The switch sleeve 31 used in the switching clutch has the asymmetric shape in the axial direction, an annular groove 32 formed on an outer periphery of the switching sleeve has a narrow portion 32b at its radial inner side with respect to a step portion 32a formed on a radial central portion, and a wide portion 32c at its radial outer side. A projecting portion 39 of a switching fork 38 engaged with the annular groove of the switching sleeve has a narrow portion 39b slidably engaged with the narrow portion of the annular groove at its tip side with respect to a step portion 39a formed on its intermediate portion, and has a wide portion 39c to be inserted into the wide portion of the annular groove at its basic side with respect to the step portion 39a. The switching sleeve preferably has the asymmetric shape by making angles between pairs of chamfers 33b, 33c respectively formed at circumferential both sides of both ends of each spline tooth 33a of an internal spline 33, different from each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  Some switching clutches used in a gear transmission mechanism of an automobile have an asymmetric shape in the axial direction, and the present invention relates to a reverse assembly preventing structure when such an asymmetric sleeve for a switching clutch is used.

  An example of a transfer device constituting a part of a gear transmission mechanism of an automobile is disclosed in Japanese Utility Model Publication No. 58-99553. 3, 4, 6, and 7 show an example of a transfer device whose main part is the same as that of the prior art. First, the prior art will be described. The transfer device includes a first output shaft (rotary shaft) 20 and a second output shaft 21 that are coaxially and rotatably connected to each other, and an input shaft 15 provided in parallel to the output shafts 20 and 21. A reduction gear shaft 28 provided between the output shafts 20, 21 and the input shaft 15, and a casing 10 comprising a front case 11 and a rear case 12 that support the shafts 15, 20, 21, 28 via bearings. have. A hub 34 is coaxially and integrally formed at the intermediate portion of the first output shaft 20, and a high speed gear (first rotating member) 26 and the same are integrally formed on the opposite side of the hub 34 to the second output shaft 21. The driven sprocket 25 is rotatably supported, and a low speed gear (second rotating member) 27 having a smaller diameter than the high speed gear 26 is rotatably supported on the second output shaft 21 side of the hub 34. A switching clutch 1 is provided between the first output shaft 20 and the high speed gear 26 and the low speed gear 27, and an intermittent clutch 40 is provided between the first output shaft 20 and the second output shaft 21.

  A silent chain 19 for transmitting rotation is wound between a drive sprocket 16 integrally formed with the input shaft 15 and a driven sprocket 25 provided on the first output shaft 20. The large-diameter gear 28 a and the small-diameter gear 28 b that are integrally formed with the reduction gear shaft 28 are engaged with the high-speed gear 26 and the low-speed gear 27, respectively, whereby the rotation of the high-speed gear 26 is decelerated and transmitted to the low-speed gear 27. The input shaft 15 is connected to an automobile engine via a transmission, and the first output shaft 20 and the second output shaft 21 are connected to a rear axle and a front axle, respectively.

  As shown in FIGS. 3 and 6, the switching clutch 1 includes a hub 34, a sleeve 2 in which an internal spline 4 that is always engaged with an external spline 34a on the outer periphery thereof, a high speed and low speed gear 26, 27, each of the projections 5 and 6 formed on the outer periphery of the protruding end portion on the hub 34 side. The sleeve 2 is reciprocated in the axial direction by a switching fork 7 in which a projecting portion 7a is engaged with an annular groove 3 formed on the outer periphery thereof, and is half of the internal spline 4 at a first position 2A shown by a solid line in FIG. The portion engages with the projection 5 of the high-speed gear 26 to couple the high-speed gear 26 to the first output shaft 20, and at the second position 2 </ b> B indicated by the two-dot chain line, the half of the internal spline 4 is the hub 34 of the low-speed gear 27. The low-speed gear 27 is coupled to the first output shaft 20 by being engaged with the projection 6, and the internal spline 4 is not engaged with any of the projections 5 and 6 at an intermediate position therebetween.

  As shown in FIG. 3, the intermittent clutch 40 is always engaged with an intermittent clutch hub 42 fixed to the end of the first output shaft 20 on the second output shaft 21 side by a spline and an external spline 42a on the outer periphery thereof. An intermittent sleeve 41 having an internal spline 41b formed thereon, and a flange portion 43 formed at an end of the second output shaft 21 on the first output shaft 20 side and having an external spline 43a formed on the outer periphery. is there. The intermittent sleeve 41 is reciprocated in the axial direction by an intermittent fork 45 in which the protruding portion 45a is engaged with an annular groove 41a formed on the outer periphery thereof, and is an internal spline at a fourth position 41D indicated by a two-dot chain line in FIG. The half of 41b engages with the external spline 43a of the flange 43 to connect the second output shaft 21 to the first output shaft 20, and the internal spline 41b is connected to the external spline 43a at the third position 41C indicated by the solid line. And the connection of the second output shaft 21 to the first output shaft 20 is released. The intermittent clutch 40 is of a synchronous mesh type.

  Next, as shown in FIG. 4, the shift device that operates the switching clutch 1 and the intermittent clutch 40 is switched with both ends supported by the casing 10 so as to be parallel to the first and second output shafts 20 and 21. A fork shaft 50 and a guide shaft 51 are provided for guiding and supporting the fork 7 and the intermittent fork 42 so as to be slidable in the axial direction. The fork shaft 50 is supported by the casing 10 so as to be slidable in the axial direction, and a rack 52a formed in a rear end portion protruding into the sub case 13 fixed to the rear side of the rear case 12 intersects with the rack 52a. It is supported and meshed with a pinion 52b reciprocally rotated by an actuator (motor) 53 and reciprocated. The guide shaft 51 is supported by the pin 51a so as not to move in the axial direction. For the fork shaft 50 provided with the two retaining rings 54a and 54b, the switching fork 7 and the intermittent fork 42 arranged in series with each other are slidable between the retaining rings 54a and 54b. For the guide shaft 51 provided with three retaining rings 55a, 55b, 55c, the switching fork 7 is between the two retaining rings 55a, 55b, and the intermittent fork 42 is between the two retaining rings 55b, 55c. Is slidable.

  As shown by the solid line in FIG. 4, in the state where the switching fork 7 is in the first position 7A where it abuts against the retaining ring 55a and the intermittent fork 45 is in the fourth position 45D where it abuts against the retaining ring 55c, The forks 7 and 45 are provided inside thereof and the balls 59a and 59b pressed by the springs are engaged with the annular grooves 58a and 58b having a trapezoidal cross section formed in the guide shaft 51 to be elastic to the guide shaft 51, respectively. The interlock pins 60a and 60b that are slidably provided in the fitting holes formed in the portion between the shafts 50 and 51 have an arc-shaped cross section formed in the guide shaft 51. Aligned and engageable with each annular groove 57a, 57b. Further, the circular grooves 56a and 56b having an arc-shaped cross section formed in the fork shaft 50 are provided with an interlock pin 60a when the forks 7 and 45 are slightly separated from the retaining rings 54a and 54b as shown by the solid lines in FIG. , 60b are not aligned. When the interlock pins 60a and 60b are not aligned with the annular grooves 56a and 56b of the fork shaft 50, they are engaged with the annular grooves 57a and 57b so as not to be detached. Is locked to the guide shaft 51 so as not to move in the axial direction. However, if the fork shaft 50 moves and the annular groove 56a is aligned with the interlock pin 60a, the interlock pin 60a can be detached from the annular groove 57a, so that the switching fork 7 has a larger elastic locking force by the ball 59a. When force is applied, the guide shaft 51 can move. Similarly, if the annular groove 56b is aligned with the interlock pin 60b, the interlock pin 60b can be detached from the annular groove 57b, so that the intermittent fork 45 is formed by the ball 59b. When a force larger than the elastic locking force is applied, the guide shaft 51 can be moved.

  Next, the operation of the above-described prior art will be described. In the state shown by the solid line in FIG. 4, since the switching fork 7 is in the first position 7A, the switching sleeve 2 is in the first position 2A, and the intermittent fork 45 is in the fourth position 45D, so the intermittent sleeve 41 is in the fourth position 41D. is there. In this state, as apparent from FIG. 3, the high speed gear 26 is coupled to the first output shaft 20 by the switching clutch 1, and the second output shaft 21 is coupled to the first output shaft 20 by the intermittent clutch 40. The engine power is transmitted from the high speed gear 26 to the first output shaft 20, transmitted from the first output shaft 20 to the rear wheels, and transmitted from the second output shaft 21 to the front wheels. That is, the transfer device is in a high-speed four-wheel drive state. If the fork shaft 50 is moved rightward in FIG. 4 by the actuator 53 via the pinion 52b and the rack 52a from this state, the retaining ring 54b first hits the intermittent fork 45 and the annular groove 56b is aligned with the interlock pin 60b. Further, if the fork shaft 50 is moved to the right, a rightward force is applied to the intermittent fork 45 via the retaining ring 54b, so that the interlock pin 60b is engaged with the annular groove 56b and disengaged from the annular groove 57b. The intermittent fork 45 is released from the elastic engagement by the annular groove 58b and the ball 59b, moves to the right, and stops at the third position 45C contacting the retaining ring 55b. The switching fork 7 remains at the first position 7A. In this state, the first output shaft 20 and the high speed gear 26 are coupled by the switching clutch 1, and the connection between the first output shaft 20 and the second output shaft 21 by the intermittent clutch 40 is disengaged. Driven.

  When the fork shaft 50 is moved leftward by the actuator 53 via the pinion 52b and the rack 52a from the state shown by the solid line in FIG. 4, the retaining ring 54a first hits the switching fork 7 and the annular groove 56a is aligned with the interlock pin 60a. If the fork shaft 50 is further moved to the left, a leftward force is applied to the switching fork 7 via the retaining ring 54a, so that the interlock pin 60a is engaged with the annular groove 56a and engaged with the annular groove 57a. The switching fork 7 is moved to the left by releasing the elastic engagement between the annular groove 58a and the ball 59a, and stopped at the second position 7B contacting the retaining ring 55b. The intermittent fork 45 remains in the fourth position 45D. In this state, the first output shaft 20 and the low speed gear 27 are coupled by the switching clutch 1, and the first output shaft 20 and the second output shaft 21 remain connected by the intermittent clutch 40. It will be in a wheel drive state. In this case, if the fork shaft 50 is stopped halfway so that the switching fork 7 stops between the first position 7A and the second position 7B, both the high speed gear 26 and the low speed gear 27 are moved by the switching clutch 1. Since it is not coupled to one output shaft 20, the transfer device is in a neutral state in which no power is transmitted.

In the transfer device as described above, since the low speed gear 27 has a lower rotational speed than the high speed gear 26, the driving torque from the engine transmitted from the low speed gear 27 to the first output shaft 20 via the switching clutch 1 is high speed. It becomes larger than the driving torque from the engine transmitted from the gear 26 to the first output shaft 20 via the switching clutch 1. As described above, the torque is transmitted by selectively engaging the spline teeth 4a of the internal spline 4 of the switching sleeve 2 and the protrusions 5 and 6 of the high-speed and low-speed gears 26 and 27. A pair of chamfers on both sides in the circumferential direction are provided on one end of the projection 5 and the spline teeth 4a facing each other and on the other end of the projection 6 and the spline teeth 4a as shown in the inner surface view of the switching sleeve 2 shown in FIG. 4b, chamfer 5a and chamfer 6a are formed to facilitate such selective engagement. In a normal manually operated transfer device, the angle α1 between each pair of chamfer 4b, chamfer 5a and chamfer 6a is the same.
Japanese Utility Model Publication No. 58-99553 (FIG. 1).

  As shown in FIG. 7, the chamfer 4b and the chamfer 6a abut at the start of meshing of the spline teeth 4a of the switching sleeve 2 and the projection 6 of the low speed gear 27, and the axial pressure applied to the spline teeth 4a is F. The pressing force acting in the direction orthogonal to 4b is F1, and the force by which the spline teeth 4a push the protrusion 6 in the circumferential direction is F2. Similarly, at the start of meshing of the spline teeth 4a of the switching sleeve 2 and the projections 5 of the high speed gear 26, if the axial pressing force applied to the spline teeth 4a is F, the spline teeth 4a push the projections 5 in the circumferential direction. The force is F2.

  On the other hand, in the transfer device as described above, torque transmitted from the low speed gear 27 to the first output shaft 20 via the switching clutch 1 is transmitted from the high speed gear 26 to the first output shaft 20 via the switching clutch 1. Therefore, the axial pressing force F required to move the switching clutch 1 against the transmission torque between the low speed gear 27 and the first output shaft 20 is higher than the high speed gear 26 and the first output. The axial pressing force F required to move the switching clutch 1 against the transmission torque between the shafts 20 needs to be larger. Note that switching between the high speed gear 26 and the low speed gear 27 is usually performed by stopping the vehicle and setting the transmission in the neutral state. In this state, the transmission torque should be zero. Since a certain amount of transmission torque exists due to the residual torque of the torque converter and clutch, the viscosity of the lubricating oil, etc., the above-described problems cannot be avoided.

  In a normal manual operation type transfer device, the fork shaft 50 is manually operated, and the increase in the axial pressing force F required to move the switching clutch 1 to the low speed gear 27 side as described above is controlled by the driver. It can be covered by increasing the power, so it will not be a big problem. However, in the case of a motor switching system in which the fork shaft 50 is reciprocated by the actuator 53 to switch between high speed and low speed, it is necessary to select the actuator 53 having a large output in accordance with the axial pressing force required for switching to low speed. Therefore, there is a problem that the shift device for switching each clutch becomes large and the cost increases.

  As shown in FIG. 8, the problem is that the angle between the projection 5 of the high-speed gear 26 and the chamfers 5a and 4b formed at one end of the spline teeth 4a facing the same remains α1, and the low-speed gear 27 This can be solved by making the angle α2 between the chamfers 6b and 4c formed at the other end of the spline teeth 4a opposite to the projection 6 smaller than α1. In this way, the force by which the spline teeth 4a push the protrusions 5 in the circumferential direction at the start of meshing of the spline teeth 4a of the switching sleeve 2 and the protrusions 5 of the high speed gear 26 is F2 as in FIG. At the start of meshing of the spline teeth 4a of the switching sleeve 2 and the projection 5 of the high speed gear 26, the chamfer 4c and the chamfer 6b come into contact with each other. If the axial pressing force applied to the spline teeth 4a is F, the chamfer 4c acts in a direction orthogonal to the chamfer 4c. The pressing force is F3 larger than F1, and the force by which the spline teeth 4a push the protrusion 6 in the circumferential direction is F4 larger than F2. Therefore, even if the axial pressing force applied to the spline teeth 4a remains F, the switching clutch 1 is moved against the large torque transmitted from the low speed gear 27 to the first output shaft 20 via the switching clutch 1. Thus, switching to the low speed side can be performed.

  The angle α1 is the high speed gear 26 and the switching sleeve 2 with respect to the torque transmitted from the high speed gear 26 to the first output shaft 20 when the axial pressure F set in the design is applied. The angle α2 is similarly set to the torque transmitted from the low-speed gear 27 to the first output shaft 20 by setting the angle α2 so that the internal spline 4 can be engaged with the protrusion 5. On the other hand, the low speed gear 27 and the switching sleeve 2 are rotated relative to each other so that the internal spline 4 can be engaged with the protrusion 6.

  Thus, the angle α2 of the chamfer 4c formed on the side engaged with the protrusion 6 of the low speed gear 27 is made smaller than the angle α1 of the chamfer 4b formed on the side engaged with the protrusion 5 of the high speed gear 26. In the switching sleeve 2 having an asymmetric shape in the axial direction, it is necessary to assemble the switching sleeve 2 to the first output shaft 20 in a predetermined direction. When the switching sleeve 2 is assembled in the opposite direction, the switching sleeve 2 is switched to the low-speed gear 27 side. The function of increasing the force with which the spline teeth 4a push the protrusions 6 in the circumferential direction cannot be achieved. However, in the conventional transfer device, as shown in FIG. 6, the annular groove 3 formed in the switching sleeve 2 has a simple groove shape, and the protruding portion 7 a formed in the switching fork 7 can be inserted into the annular groove 3. Since the thickness is constant, the switching fork 7 can be inserted into the annular groove 3 even when the switching sleeve 2 is mistakenly assembled in the axial direction opposite to that shown in FIG. As for the engagement of the switching fork 7 with the switching sleeve 2, the parts 25 to 27, the switching clutch 1 and the intermittent clutch 40 are assembled to the output shafts 20 and 21, and the switching fork 7 and the intermittent fork 45 are assembled to the shafts 50 and 51. (At the same time, the intermittent fork 45 is also assembled to the intermittent sleeve 41). The sub-assembly thus assembled is attached to the front case 11, the input shaft 15 and the reduction gear shaft 28 are further attached, the silent chain 19 is attached, and then the rear case 12 is covered to complete the assembly. However, in the case of the structure described above, even when the switching sleeve 2 is mistakenly assembled in the reverse direction, this error is not noticed in the middle of the assembly, and is first found out when it is operated after the vehicle assembly is completed. There is a problem that reworking this reverse assembly requires a great deal of time and effort to disassemble and reassemble what has been once assembled. The object of the present invention is to solve each of these problems.

  For this reason, the reverse assembly prevention structure for an asymmetric sleeve for a switching clutch according to the present invention has an annular groove formed on the outer periphery and an inner spline formed on the inner periphery, and is provided coaxially and integrally with the rotating shaft. The internal spline is always meshed with the external spline of the hub so that it can slide in the axial direction, and is reciprocated in the axial direction by a switching fork whose protrusion is engaged with the annular groove, so that a part of the internal spline rotates. A switching clutch sleeve configured to be selectively engaged with a first protrusion of a first rotating member and a second protrusion of a second rotating member that are rotatably provided on both sides of a hub of the shaft. The annular groove has a narrower portion on the radially inner side than the step portion formed at the intermediate portion in the radial direction and a wider portion on the radially outer side than the stepped portion formed in the intermediate portion in the radial direction. The front end side of the step portion formed in the intermediate portion is a narrow portion slidably engaged with the narrow portion of the annular groove, and the root side of the step portion can be inserted into the wide portion of the annular groove. It is characterized by having a wide part.

  In the structure for preventing reverse assembly of the asymmetric sleeve for the switching clutch according to the previous item, the transmission is transmitted between the first rotating member and the rotating shaft by the engagement between the internal spline of the sleeve and the first protrusion of the first rotating member. The torque is made smaller than the torque transmitted between the second rotating member and the rotating shaft by the engagement between the internal spline of the sleeve and the second protrusion of the second rotating member. The angle between a pair of third chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion on the second rotating member side of the spline teeth and the outer periphery of the tip portion on the hub side of the second protrusion meshing with the third chamfer At least one of the angles between the pair of fourth chamfers formed on both sides in the circumferential direction of the inner spline is formed on both sides in the circumferential direction of the outer periphery of the tip portion on the first rotating member side of each spline tooth of the internal tooth spline. A pair of first chamfers It is preferable that the angle is smaller than at least one of the angle between the pair of second chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion on the hub side of the first protrusion meshing with the first projection. .

  In the structure for preventing reverse assembly of the asymmetric sleeve for the switching clutch described in the preceding paragraph, the switching fork is driven back and forth by the actuator to selectively move the internal spline of the sleeve to the first and second protrusions of the first and second rotating members. It is preferable to engage.

  As described above, according to the present invention, the sleeve has an asymmetrical shape in the axial direction, and the annular groove has a narrower portion on the radially inner side than the step portion formed in the radially intermediate portion and has a radius larger than that. The projecting part of the switching fork is a narrow part that is slidably engaged with the narrow part of the annular groove, and the projecting part of the switching fork is slidably engaged with the narrow part of the annular groove. Since the base side is a wide part that can be inserted into the wide part of the annular groove, when the switching sleeve is mistakenly assembled in the reverse direction in the axial direction, the stepped portion of the protruding part abuts the outer peripheral surface of the switching sleeve. Alternatively, the tip of the protruding portion of the switching fork contacts the step of the annular groove of the switching sleeve, and the protruding portion is not inserted into the annular groove to the normal position, and the switching fork floats radially outward from the switching sleeve. It will be in a stateAccordingly, it is immediately found that the assembly has been mistakenly reversed, and it is possible to immediately correct the error and proceed to the next assembling process. Therefore, labor required for rework can be greatly reduced.

  The torque transmitted between the first rotating member and the rotating shaft by the engagement between the internal spline of the sleeve and the first protrusion of the first rotating member is the second protrusion of the inner rotating spline of the sleeve and the second rotating member. The circumference of the outer periphery of the tip end portion of each spline tooth on the side of the second rotating member of the internal spline teeth is made smaller than the torque transmitted between the second rotating member and the rotating shaft Between a pair of fourth chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion on the hub side of the second protrusion meshing with the angle between the pair of third chamfers formed on both sides in the direction At least one of the angles of the pair of first chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion of the internal spline on the first rotating member side of each spline tooth and meshes with the angle. Circumference of the outer periphery of the tip part on the hub side of the first protrusion According to the configuration in which the angle between the pair of second chamfers formed on the opposite sides is smaller than at least one of the angles, when switching to the second rotating member side where the transmission torque between the rotating shaft is large The switching sleeve operating force required for the switching sleeve can be set to the same level as the switching sleeve operating force required when switching to the first rotating member side where the transmission torque is small, so that the switching sleeve switching operation is facilitated.

  The switching fork is reciprocally driven by the actuator so that the internal spline of the sleeve is selectively engaged with the first and second protrusions of the first and second rotating members. When switching to the second rotating member side where the transmission torque is large and when switching to the first rotating member side where the transmission torque is small, the motor output of the actuator can be made comparable, and in either case the motor output is maximum Therefore, the actuator can be miniaturized as compared with the required function, and the manufacturing cost can be reduced.

  The best mode of the reverse assembly preventing structure for an asymmetric sleeve for a switching clutch according to the present invention will be described below with reference to the embodiments shown in FIGS. In this embodiment, a switching clutch 30 that selectively couples a high-speed gear (first rotating member) 26 and a low-speed gear (second rotating member) 27 to a first output shaft (rotating shaft) 20, and the switching clutch 30 Since the switching fork 38 to be operated is only different from the above-described conventional switching clutch 1 and switching fork 7, this difference will be mainly described.

  As shown mainly in FIG. 1, the switching clutch 30 has a hub 34 provided on the first output shaft 20 and an annular groove 32 formed on the outer periphery, and is always movable in the axial direction on an external spline 34 a of the hub 34. The switching sleeve 31 formed with the internal spline 33 to be engaged, and the outer periphery of the protruding end portion on the hub 34 side of the high-speed and low-speed gears 26 and 27 can be engaged with and disengaged from the internal spline 33. The first projection 35 and the second projection 36 are included. The hub 34 is formed coaxially and integrally with the intermediate portion of the first output shaft 20 and has external splines 34a formed on the outer periphery thereof, as in the prior art described above.

  The annular groove 32 formed on the outer periphery of the switching sleeve 31 has a narrower portion 32b on the inner side in the radial direction than the step portion 32a formed on the intermediate portion in the radial direction, and is wider on the outer side in the radial direction than the step portion 32a. This is part 32c. The internal splines 33 formed on the inner periphery of the switching sleeve 31 are substantially the same as those described with reference to FIG. 8 of the prior art, and are composed of a large number of spline teeth 33a arranged in the circumferential direction. The angle between the pair of second chamfers 35a and the pair of first chamfers 33b respectively formed at the tip of each first protrusion 35 of the high speed gear 26 and one end of each spline tooth 33a facing the first projection 35 is Each of them is α1 described above, and an angle between a pair of fourth chamfers 36a formed at the tip of each second protrusion 36 of the low speed gear 27 and the other end of each spline tooth 33a opposed thereto, and a pair of them. The angle between the third chamfers 33c is the aforementioned α2 which is smaller than α1.

  As shown in FIG. 1, the switching fork 38 is integrally formed with a projecting portion 39 that is engaged in the annular groove 32 of the switching sleeve 31, and this projecting portion 39 is a step portion formed in the middle portion thereof. The tip end side of 39a is a narrow portion 39b slidably engaged with the narrow portion 32b of the annular groove 32, and the base side of the step portion 39a can be inserted into the wide portion 32c of the annular groove 32. It has become. In this embodiment, the length of the narrow portion 39 b of the projecting portion 39 is larger than the depth of the narrow portion 32 b of the annular groove 32. In the normal assembly state shown in FIG. 1, the tip of the narrow portion 39b of the projecting portion 39 is slidable with a slight clearance or light contact with the bottom surface of the narrow portion 32b of the annular groove 32. There is a slight gap between the step 32 a of the annular groove 32 and the step 39 a of the protrusion 39. The length of the narrow portion 39b of the projecting portion 39 may be smaller than the depth of the narrow portion 32b of the annular groove 32, in the opposite case, in which case the step portion 32a and the projecting portion of the annular groove 32 are used. 39 steps 39a are lightly abutted or there is a slight gap between them, and there is a slight gap between the tip of the narrow portion 39b of the protrusion 39 and the bottom surface of the narrow portion 32b of the annular groove 32. It is formed.

  The switching fork 38 and the intermittent fork 45 reciprocated by the motor (actuator) 53 via the shift device reciprocate the switching clutch 30 and the intermittent clutch 40 so that the transfer device is in a high-speed four-wheel drive state and a high-speed two-wheel drive state. , Switch to low-speed four-wheel drive state and neutral state. Since the details are the same as those of the above-described prior art, detailed description thereof is omitted.

  As described in the description of the prior art, the engagement of the switching fork 38 with the switching sleeve 31 is performed by assembling the portions 25 to 27, the switching clutch 30 and the intermittent clutch 40 to the output shafts 20 and 21. In this state, the switching fork 38 and the intermittent fork 45 are assembled. If the switching sleeve 31 is erroneously assembled in the opposite direction in the axial direction as shown in FIG. The asymmetrical switching sleeves 31 having different chamfers 33b and 33c cannot perform their functions. However, if the switching sleeve 31 is assembled in such a reverse direction, as shown in FIG. 2, the stepped portion 39a of the protruding portion 39 abuts on the outer peripheral surface of the switching sleeve 31, or the protruding portion 39 of the switching fork 38 The tip end abuts on the step 32 a of the annular groove 32 of the switching sleeve 31, and the protruding portion 39 is not inserted into the annular groove 32 to the normal position, and the switching fork 38 is lifted radially outward from the switching sleeve 31. It becomes a state. This immediately reveals that the switching sleeve 31 has been mistakenly assembled in the reverse direction. Accordingly, since the error can be corrected immediately and the next assembly completion process can be proceeded, the labor required for reworking is greatly reduced, and the labor required for reworking this reverse assembly as in the prior art described above is greatly reduced. Can be reduced. In this case, if the switching fork 38 is mistakenly assembled in the reverse direction, it cannot be detected that the switching sleeve 31 is assembled in the reverse direction, but the normal switching sleeve 31 has a shape whose directionality can be seen at a glance. There is no risk of reverse assembly, and such a problem does not occur.

  In the embodiment described above, the switching fork 38 has been described as having the protruding portion 39 abutting on one side of the switching sleeve 31, but the protruding portion 39 is engaged in the annular groove 32 so as to straddle the switching sleeve 31. In this case, when the switching sleeve 31 is assembled in such a reverse direction, the stepped portion 39a is located on the inner side of each tip of the bifurcated portion of the projecting portion 39. The tip of the projection 39 of the switching fork 38 abuts on the step 32a of the annular groove 32 of the switching sleeve 31, and the projection 39 is not inserted into the annular groove 32 to a normal position. Since the switching fork 38 is lifted radially outward from the switching sleeve 31, it is found that the switching sleeve 31 is mistakenly assembled in the reverse direction. When the projecting portion 39 has a bifurcated shape, the step portion 39a may have an arc shape along the side surface of the bifurcated portion, or may have a planar shape in contact with the step portion 32a of the annular groove 32.

  In the above-described embodiment, a pair of the second chamfer 35a and the first chamfer 33b are formed between the tip of each first protrusion 35 of the high speed gear 26 and one end of each spline tooth 33a opposite to the tip. The angle of each is α1, and a pair of fourth chamfers 36a and third chamfers 33c are formed at the tip of each second protrusion 36 of the low speed gear 27 and the other end of each spline tooth 33a opposed thereto. The angle between is α2 smaller than α1. However, the present invention is not limited to this, and one of the pair of chamfers 35a and 33b formed at the tip of each first protrusion 35 and one end of each spline tooth 33a facing the first protrusion 35 is omitted. Instead, a pair of chamfers 36a and 33c formed on the tip of each second protrusion 36 and the other end of each spline tooth 33a facing each other are provided with a semicircular arc-shaped contact surface that contacts the other chamfer. Any one of them may be omitted, and a semicircular contact surface that contacts the other chamfer may be provided instead.

  In the above-described embodiment, the high-speed gear 26 and the low-speed gear 27 that are rotatably provided on the first output shaft 20 are selectively coupled to the first output shaft 20 by the switching clutch 30, and the switching sleeve 31 includes the two gears 26, 27 by changing the angles α1 and α2 between each pair of chamfers 33b and 33c formed at both ends of the spline teeth 33a of the internal spline 33 according to the difference in the transmission torque of 27, respectively, If it does in this way, it is required when switching the operation force of the switching sleeve 31 required when switching to the low-speed gear 27 side with a large transmission torque between the 1st output shafts 20 to the high-speed gear 26 side with a small transmission torque. Since the operating force of the switching sleeve 31 can be made comparable, the switching operation of the switching sleeve 31 is facilitated. However, the present invention is not limited to this, and the switching sleeve 31 has the same angle between each pair of chamfers formed at both ends of the spline teeth 33a of the internal spline 33, and has a function different from the transmission torque. The switching sleeve 31 is implemented so as to selectively transmit power between the rotating shaft 20 and a first rotating member and a second rotating member that are rotatably provided on the rotating shaft 20. You can also.

  In the above-described embodiment, the switching fork 38 is reciprocated by the motor 53 to selectively engage the internal spline 33 of the sleeve 31 with the first and second protrusions 35 and 36 of the high speed and low speed gears 26 and 27. In this way, the output of the motor is approximately the same when switching to the low speed gear 27 side where the transmission torque between the rotary shaft 20 is large and when switching to the high speed gear 26 side where the transmission torque is small. In any case, since the motor 53 can be set to the maximum output, the motor 53 can be reduced in size as compared with the required function, thereby reducing the manufacturing cost. . However, the present invention is not limited to this, and the switching fork 38 is reciprocated by manual operation to selectively engage the internal spline 33 of the sleeve 31 with the first and second protrusions 35 and 36 of the high-speed and low-speed gears 26 and 27. In this case, the operation force when switching to the low-speed gear 27 side where the transmission torque between the rotary shaft 20 is large and that when switching to the high-speed gear 26 side where the transmission torque is small are almost the same. Therefore, manual switching operation of the switching sleeve 31 is facilitated.

It is sectional drawing which shows the principal part of one Embodiment of the reverse assembly prevention structure of the asymmetrical sleeve for switching clutches by this invention. It is a fragmentary sectional view explaining an effect | action at the time of reversely assembling the asymmetrical sleeve of embodiment shown in FIG. It is sectional drawing which shows the whole structure of the transfer apparatus provided with the switching clutch. It is a figure which shows the structure of the shift apparatus which operates the switching clutch of the transfer apparatus shown in FIG. It is drawing explaining the shape of an internal-tooth spline at the time of seeing the asymmetrical sleeve shown in FIG. 1 from the inside, and its effect | action. It is sectional drawing which shows the principal part of an example of the sleeve for switching clutch by a prior art. FIG. 7 is a view similar to FIG. 5 for explaining the shape and operation of the internal spline of the conventional sleeve shown in FIG. 6. FIG. 6 is a view similar to FIG. 5 for explaining the shape and operation of an example of an internal spline of an asymmetric sleeve according to the prior art. It is a fragmentary sectional view explaining the effect | action at the time of reversely assembling the asymmetric sleeve by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Rotating shaft (1st output shaft), 26 ... 1st rotating member (high speed gear), 27 ... 2nd rotating member (low speed gear), 31 ... Sleeve (switching sleeve), 32 ... Annular groove, 32a ... Step part 32b ... narrow portion, 32c ... wide portion, 33 ... internal tooth spline, 33a ... spline tooth, 33b ... first chamfer, 33c ... third chamfer, 34 ... hub, 34a ... external spline, 35 ... first protrusion 35a ... 2nd chamfer, 36 ... 2nd protrusion, 36a ... 4th chamfer, 38 ... switching fork, 39 ... protrusion, 39a ... stepped part, 39b ... narrow part, 39c ... wide part, 53 ... actuator (motor) ).

Claims (3)

An annular groove is formed on the outer periphery and an inner tooth spline is formed on the inner periphery. The inner tooth spline is always meshed with the outer tooth spline of the hub coaxially and integrally provided on the rotating shaft so as to be slidable in the axial direction. And a part of the internal spline is rotatably provided on both sides of the hub of the rotating shaft by being reciprocated in the axial direction by a switching fork whose protrusion is engaged with the annular groove. In the switching clutch sleeve configured to be selectively engaged with the first protrusion of the rotating member and the second protrusion of the second rotating member, the sleeve has an asymmetric shape in the axial direction, and the annular groove has a radial direction thereof The inner side in the radial direction is a narrower part than the step part formed in the intermediate part and the outer side in the radial direction is a wider part than the step part formed in the intermediate part. in front A switching clutch characterized in that a narrow portion that is slidably engaged with a narrow portion of the annular groove and a wide portion that can be inserted into the wide portion of the annular groove at a base side from the stepped portion. Structure for preventing reverse assembly of asymmetric sleeves. 2. The reverse assembly prevention structure for an asymmetric sleeve for a switching clutch according to claim 1, wherein an engagement between an internal spline of the sleeve and a first protrusion of the first rotating member results in engagement between the first rotating member and the rotating shaft. The torque transmitted between the second rotating member and the rotating shaft is smaller than the torque transmitted between the inner rotating spline of the sleeve and the second protrusion of the second rotating member. Thus, the angle between the pair of third chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion of the inner tooth spline on the second rotating member side of each spline tooth, and the first meshing with the angle. At least one of the angles between a pair of fourth chamfers formed on both sides in the circumferential direction of the outer periphery of the tip portion on the hub side of the two protrusions is the first rotating member of each spline tooth of the internal spline Side tip An angle between a pair of first chamfers formed on both sides of the outer circumference in the circumferential direction and a pair formed on both sides in the circumferential direction of the outer circumference of the tip portion on the hub side of the first protrusion meshing with the first chamfer A structure for preventing reverse assembly of an asymmetric sleeve for a switching clutch, characterized in that the angle is smaller than at least one of the angles between the second chamfers. 3. The structure for preventing reverse assembly of an asymmetric sleeve for a switching clutch according to claim 2, wherein the switching fork is reciprocally driven by an actuator to move the internal splines of the sleeve to the first and second rotating members of the first and second rotating members. A reverse assembly preventing structure for an asymmetric sleeve for a switching clutch, wherein the structure is selectively engaged with a protrusion.

Images