JP2008082520A - Pole rachet assembling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pole rachet assembling structure for allowing easy assembly of a shifter assembly into a drum center. <P>SOLUTION: The pole rachet assembling structure comprises an assembling tool 40 which is fitted to the outer periphery of the shifter assembly 22 for displacing each rachet pole 32 to a shifter inner periphery side against the energizing force of an energizing means, and which is elastically deformed to a shifter outer periphery side with the energizing force of the energizing means so as to be fitted to the inner periphery of an insertion hole 24 of a guide plate 23. The assembling tool 40 has a notch 41 in/out of which a protruded portion 24a protruded on the inner periphery of the insertion hole 24 of the guide plate 23 is moved through the axial inside. In the state that the protruded portion 24a is held between the bottom of the notch 41 and a lower outer periphery 34a of a shifter body 31, the shifter assembly 22 and the guide plate 23 are integrally held via the assembling tool 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an assembly structure of a pole ratchet mechanism used for a change mechanism of a transmission of a vehicle engine.

Conventionally, a drum center is coaxially and integrally rotatable at one end of a shift drum supported by a case body, and a shifter assembly having a ratchet pole biased toward the outer periphery is disposed in the drum center. The assembly can be rotated together with the drum center from a predetermined initial rotation position, and after the rotation, only the shifter assembly can be rotated in the reverse direction in cooperation with a guide plate fixed to the case body. A pole ratchet mechanism that enables intermittent feeding of the drum center and the shift drum by repeating forward and reverse rotation of the shifter assembly by returning to the initial position is known (for example, see Patent Document 1).
JP 2001-263484 A

By the way, in the above-mentioned pole ratchet mechanism, the shifter assembly is formed by assembling a plurality of pole ratchets and their biasing means, which are relatively small parts, to the shifter body, and each pole ratchet is used as the biasing force of the biasing means. In contrast, since it is necessary to assemble the shifter assembly in the drum center in a state of being displaced toward the inner peripheral side, there is a problem that it is relatively difficult to assemble the shifter assembly into the drum center.
Therefore, the present invention provides a pole ratchet assembling structure capable of easily assembling the shifter assembly into the drum center.

  As a means for solving the above-mentioned problems, the invention described in claim 1 is characterized in that it rotates coaxially and integrally with one end of a shift drum (for example, the shift drum 11 of the embodiment) supported by the case body (for example, the crankcase 2 of the embodiment). A drum center (for example, the drum center 21 of the embodiment) that can be provided, and a shifter assembly (for example, the shifter of the embodiment) that faces an inner space (for example, the inner space K of the embodiment) that opens to the outside in the axial direction of the drum center. An assembly 22), and a guide plate (for example, the guide plate 23 of the embodiment) having an insertion hole (for example, the insertion hole 24 of the embodiment) facing the shifter assembly and fixed to the case body, A shifter assembly is a shifter body (for example, the shifter body 31 of the embodiment) that is coaxial and relatively rotatable with respect to the drum center, and the shifter body And at least a pair of ratchet poles (for example, the ratchet pole 32 of the embodiment) to be assembled, and biasing means (for example, the biasing plunger 33 of the embodiment) for biasing each ratchet pole toward the shifter outer peripheral side. When the assembly is at a predetermined initial rotation position, rotation in both directions with respect to the drum center is restricted by at least one ratchet pole being displaced toward the outer periphery of the shifter and engaging the inner periphery of the drum center. When the shifter assembly rotates together with the drum center in one direction from the initial rotation position, the ratchet pawl slidably contacts the inner periphery of the insertion hole of the guide plate (for example, the pole ratchet mechanism 20 of the embodiment). ) Is attached to the outer periphery of the shifter assembly and the attachment Displacement of the ratchet poles against the inner peripheral side of the shifter against the biasing force of the means, and an assembly that is elastically deformed to the outer peripheral side of the shifter by the biasing force of the biasing means and fits into the inner periphery of the insertion hole of the guide plate A jig (for example, the assembling jig 40 of the embodiment) is provided, and the guide plate protrudes to the inner periphery of the insertion hole, and the outer peripheral portion of the shifter body (for example, the lower outer peripheral portion 34a of the embodiment) from outside in the axial direction. The assembling jig has a notch portion (for example, the notch portion 41 of the embodiment) that makes contact with the projecting portion (for example, the notch portion 41 of the embodiment). With the shifter assembly facing the insertion hole of the guide plate, the assembling jig is fitted from the outside in the axial direction to the outer periphery of the shifter assembly and the inner periphery of the insertion hole, and the bottom of the notch and the The convex portion is sandwiched between the outer peripheral portion of the lid body, and the shifter assembly and the guide plate are integrally held via the assembly jig, and these are assembled to the drum center and the case body. .

  The invention described in claim 2 is characterized in that the assembly jig has a C-shape in an axial view covering at least a half circumference of the outer periphery of the shifter assembly, and the notch is formed in a middle portion in the circumferential direction. On both sides of the convex portion in the insertion hole of the guide plate, an enlarged diameter portion (for example, an enlarged diameter portion 24b in the embodiment) that can be fitted to both sides in the circumferential direction of the assembly jig is formed.

  According to a third aspect of the present invention, the two enlarged diameter portions include an enlarged portion having a large expanded width (for example, an enlarged portion 24c in the embodiment) and a narrow portion having a small expanded diameter (for example, the narrow portion 24d in the embodiment). And both side portions in the circumferential direction of the assembly jig are fitted into the narrow portion.

  According to the invention described in claim 1, the shifter assembly having a relatively small part is integrally held with the relatively large guide plate by using an assembly jig having a simple structure, thereby the shifter assembly. In addition, the guide plate can be easily assembled to the drum center and the case body.

  According to the second aspect of the present invention, the shifter assembly can be held well in a good balance.

  According to the invention described in claim 3, after suppressing the plate thickness of the assembly jig, it can be fitted to the outer periphery of the shifter assembly and to the inner periphery of the guide plate.

Embodiments of the present invention will be described below with reference to the drawings.
A vehicle reciprocating engine (an internal combustion engine, hereinafter simply referred to as an engine) 1 shown in FIG. 1 has a basic configuration in which a cylinder portion 3 is erected on a crankcase 2, and a reciprocating piston 8 in the cylinder portion 3. The movement is converted into the rotational movement of the crankshaft 9 in the crankcase 2. The crankcase 2 also serves as a transmission case (transmission case) that houses a transmission (transmission) 4.

  Referring also to FIG. 2, the transmission 4 mainly includes a main shaft 5 and a counter shaft 6 that are parallel to the crankshaft 9 and a transmission gear group 7 that is supported across the shafts 5 and 6. In the figure, reference numeral 5a denotes a reverse idle shaft parallel to the shafts 5 and 6. The rotational power of the crankshaft 9 is appropriately decelerated from the main shaft 5 via an arbitrary gear of the transmission gear group 7 and transmitted to the countershaft 6, and then output to the outside from the output section 6a below.

  The gear change of the transmission 4 is performed by a change mechanism 10 disposed below the transmission 4. The change mechanism 10 operates a plurality of shift forks 12 according to the pattern of the lead grooves 11a formed on the outer periphery thereof by rotation of a hollow cylindrical shift drum 11 parallel to both shafts 5 and 6, and a transmission gear group. The gear used for power transmission between both shafts 5 and 6 in 7 is switched. A shift spindle 13 parallel to the shift drum 11 is disposed below the shift drum 11. In the figure, reference numeral 12a denotes a fork rod parallel to the shift drum 11.

  Hereinafter, the direction along which the shafts 5 and 6 and the shift drum 11 and the like follow is referred to as the front-rear direction, and the front thereof is indicated by an arrow FR in the figure. Further, in the arrow view (axial view, front view) along the axis C1 of the shift drum 11, the direction along the straight line T1 connecting the axis C1 of the shift drum 11 and the axis C2 of the shift spindle 13 is defined as the up and down direction. Is indicated by an arrow UP in the figure, a direction orthogonal to the straight line T1 is defined as a left-right direction, and the left side is indicated by an arrow LH in the figure.

  The shift drum 11 and the shift spindle 13 are supported by the crankcase 2 so as to be rotatable about its axis. A plate-like shift arm 14 orthogonal to the front is fixed to the front portion of the shift spindle 13. The arm body 14 a of the shift arm 14 extends upward toward the front of the shift drum 11, and the tip end portion of the arm body 14 a and the front end portion of the shift drum 11 are engaged via the pole ratchet mechanism 20.

  When the shift spindle 13 and the shift arm 14 reciprocate forward and backward by a predetermined angle, the shift drum 11 is rotated by a predetermined angle in one direction via the pole ratchet mechanism 20, and the shift fork 12 is moved to the shift drum. The shift stage of the transmission 4 is changed to a predetermined shift stage by moving in the axial direction of the fork rod 12a along the 12 lead grooves 11a. 2 denotes an electric motor that applies a rotational force to the shift spindle 13. That is, the transmission 4 is an electric semi-automatic (or automatic) transmission that changes the gear position by driving control of the electric motor 15. Note that the transmission 4 may be a manual transmission that does not have an electric motor or the like and changes the gear position by an operation of a pedal or the like by a driver.

  As shown in FIGS. 3 to 5, the pole ratchet mechanism 20 includes a drum center 21 that is coaxially and integrally rotatable at the front end portion of the shift drum 11, and an inner portion that opens forward (axially outside) in the drum center 21. A shifter assembly 22 that faces the space K and a guide plate 23 that has an insertion hole 24 that faces the shifter assembly 22 and is fixed to the crankcase 2 are provided.

  The shift drum 11 and the drum center 21 are fastened by a bolt 25 coaxial with them. From the head of the bolt 25, a rotation shaft 25a for supporting the shifter assembly 22 protrudes forward. In FIG. 4, reference numeral 25b is a knock pin that restricts the relative rotation of the front end of the shift drum 11 and the rear end of the drum center 21, and reference numeral 25c is a straddle of the front end of the shift drum 11 and the rear end of the drum center 21. The ball bearings that rotatably support these outer peripheries are respectively shown.

  A locking pin 26 protrudes forward from a portion offset from the axis C1 on the front surface of the shifter assembly 22. The front end portion of the arm main body 14a of the shift arm 14 is positioned immediately in front of the pole ratchet mechanism 20, and a locking pin 26 is inserted into a long hole 14c formed in the front end portion. The rotational force of the shift spindle 13 is input from the shift arm 14 to the pole ratchet mechanism 20 via the locking pin 26.

  The shift arm 14 has a guide arm 14b that extends to the left at a substantially right angle with respect to the arm body 14a, and a guide hole 14d is formed at the tip of the guide arm 14b. The guide hole 14d has a predetermined width in the rotation direction of the shift arm 14, and a guide pin 27 fixed to the crankcase 2 is inserted into the guide hole 14d. Here, the rotation position of the shift arm 14 in the case where the guide pin 27 is positioned at the center of the width in the rotation direction of the guide hole 14d is defined as the initial position. The rotation angles of the shift arm 14 in the forward and reverse directions from the initial position are defined by the outer periphery of the guide pin 27 contacting the inner periphery of both ends of the guide hole 14d.

  A locking piece 14e protrudes rearward from the inner peripheral portion of the guide hole 14d, and the locking piece 14e is associated with the working end of a return spring 28 disposed just behind the base end portion of the shift arm 14. Match. The return spring 28 is a torsion coil spring through which the shift spindle 13 is inserted, and both coil ends extend substantially parallel to the left and sandwich the locking piece 14e and the guide pin 27 from above and below. As a result, when the shift arm 14 rotates forward and backward from the initial position, the locking piece 14e and the guide pin 27 move relative to each other so that both coil ends of the return spring 28 are separated to return the shift arm 14 to the initial position. A biasing force acts.

  When the shift arm 14 is in the initial position, the shift drum 11 is in a rotational position corresponding to a predetermined gear position. The rotation of the shift drum 11 at this time is regulated by a drum stopper (detent) 29 via the drum center 21. The drum stopper 29 includes a stopper arm 29b that is rotatably supported by a rotation shaft 29a fixed to the crankcase 2, a stopper roller 29c that is rotatably supported at the tip of the stopper arm 29b, And a torsion coil spring 29d for urging the stopper arm 29b to press the stopper roller 29c against the outer periphery of the drum center 21.

  On the other hand, the outer periphery of the drum center 21 is formed with a plurality of outer peripheral recesses 21a each having a circular arc shape that is generally aligned with the outer periphery of the stopper roller 29c. The drum center 21 and the drum stopper 29 cooperate with each other. Thus, a predetermined rotation restricting force is applied to the shift drum 11, and the shift drum 11 can be rotated against the rotation restricting force.

  The shifter assembly 22 includes a shifter body 31 that is coaxial and relatively rotatable with respect to the drum center 21, a pair of ratchet poles 32 that are relatively small components, and a biasing plunger 33 that biases the ratchet poles 32 toward the outer periphery of the shifter. Assemble.

  The shifter body 31 includes a flat cylindrical base portion 34 accommodated in the drum center 21, a reduced diameter portion 35 that protrudes coaxially and forward from the base portion 34, and a base through the reduced diameter portion 35. A disk-shaped arm portion 36 is provided in front of the portion 34 so as to be spaced apart from and parallel to the disk portion. A through hole 37 is formed in the central portion of the shifter body 31 so as to penetrate the shifter body 31 in the front-rear direction. The rotation shaft 25a is inserted into the through-hole 37, so that the shifter assembly 22 can be 11 is supported so as to be relatively rotatable. In addition, the base part 34 and the arm part 36 share the substantially same diameter cylindrical reference | standard outer peripheral surface.

  Here, a locking pin 26 projects from the upper front surface of the arm portion 36, and is positioned at and above the center of the through hole 37 in the axial view of the shifter body 31 (in the axial direction of the shift drum 11). A straight line connecting the centers of the locking pins 26 is defined as a shifter center line T2, and a rotation position of the shifter assembly 22 when the shifter center line T2 and the straight line T1 overlap each other is defined as an initial rotation position. When the shifter assembly 22 is in the initial rotation position, the shift arm 14 is in the initial position. The shifter body 31 has a line-symmetric configuration with respect to the shifter center line T2 when viewed in the axial direction.

  The upper outer peripheral portion 36a of the arm portion 36 projects outward from the reference outer peripheral surface in the axial direction of the shifter body 31, and the locking pin 26 projects from the front surface of the upper outer peripheral portion 36a. On the other hand, a portion of the arm portion 36 that is opposite to the locking pin 26 in the radial direction is cut out in an arc shape when viewed in the axial direction of the shifter body 31 and is retracted to the inner peripheral side from the reference outer peripheral surface. Thereby, the front surface of the lower outer peripheral portion 34a of the base portion 34 faces forward (outside in the axial direction).

  Referring also to FIG. 6, a pair of notch portions 38 that can accommodate the ratchet poles 32 are formed on both sides of the base portion 34 and the outer peripheral portion of the reduced diameter portion 35 with the shifter center line T2 interposed therebetween. It is formed in a substantially C shape when viewed in the axial direction. Each ratchet pole 32 is a thick plate having a rectangular shape parallel to the axis C1, and one side of the ratchet pole 32 is a semi-cylindrical shaft 32a along the longitudinal direction, and the opposite side 32b is centered on the shaft 32a. Can be rotated so as to move to the inner and outer peripheral sides of the shifter body 31.

  On the other hand, a plurality of inner circumferential recesses 21b are formed at predetermined angles on the inner circumferential surface of the drum center 21 having the same diameter as the reference outer circumferential surface of the base portion 34, and the opposite side portions 32b of each ratchet pole 32 are The base portion 34 can be engaged with any one of the inner peripheral recesses 21b at the same time in a state protruding from the reference outer peripheral surface to the outer peripheral side.

  The inner circumferential recess 21b has a trapezoidal shape when viewed in the axial direction of the shifter body 31 and the drum center 21, and the opposite side 32b of the ratchet pole 32 projecting from the reference outer circumferential surface of the base 34 abuts on one side thereof. The rotation of the shifter assembly 22 in the direction is restricted. On the other hand, when the shifter assembly 22 tries to rotate in the direction opposite to the abutting direction, the outer surface of the ratchet pole 32 comes into contact with the other side of the inner peripheral recess 21b of the drum center 21 and the opposite side 32b The protrusion of the base portion 34 from the reference outer peripheral surface is eliminated, and the shifter assembly 22 is allowed to rotate in the reverse direction.

  The urging plunger 33 includes a plunger main body 33a that is housed in a state in which the tip side protrudes into a cylinder hole 33c that is drilled on the opposite side 32b side of the ratchet pole 32 in each notch portion 38, and the plunger main body 33a. And a coil spring 33b contracted between the cylinder hole 33c and the bottom of the cylinder hole 33c. The tip of the plunger body 33a is brought into contact with the inner surface of the ratchet pole 32 substantially vertically so that the coil spring 33b The opposite side portion 32b side of the ratchet pole 32 is urged toward the shifter outer peripheral side by the spring force. In addition, the code | symbol 33d in FIG. 6 shows the communicating hole which is connected to the bottom part of both cylinder holes 33c, and opens these to the outer periphery of the base part 34.

  The rearward movement of each ratchet pole 32 is regulated by the rear side of the ratchet pole 32 coming into contact with the bottom of the drum center 21, and the forward movement of each ratchet pole 32 has its front side at the flanges on both sides of the arm portion 36. It is regulated by contacting the part 36b. That is, the front portion of each ratchet pole 32 is located in the gap between the base portion 34 and the arm portion 36 (the outer peripheral side of the reduced diameter portion 35). A guide plate 23 having a thickness equivalent to the gap is provided so as to surround the outer periphery of the reduced diameter portion 35.

  The guide plate 23 has a plate shape orthogonal to the axis C1, and includes a rim portion 23a that forms an insertion hole 24 through which the diameter-reduced portion 35 and the front portion of each ratchet pole 32 are inserted, and a pair extending from the both sides of the rim portion 23a to the left and right. The fixing flange portion 23b is a relatively large component. The insertion hole 24 of the guide plate 23 is a convex portion protruding from the lower inner edge to the inner peripheral side based on a circular shape having a slightly smaller diameter than the reference outer peripheral surface of the shifter body 31 (the inner peripheral surface of the drum center 21). 24a and an enlarged diameter portion 24b that increases the diameter size by cutting out the inner edge portions on both sides in the circumferential direction of the convex portion 24a.

  The rear surface of the convex portion 24 a abuts the front surface of the lower outer peripheral portion 34 a of the base portion 34. Each enlarged diameter portion 24b on both sides of the convex portion 24a is an operating range in which each ratchet pole 32 operates in a state where the opposite side portion 32b is moved to the outer peripheral side when the shifter assembly 22 is rotated. In other words, the operating range of each ratchet pole 32 is separated by the convex portion 24a. Both the enlarged diameter portions 24b have a portion on the convex portion 24a side as an enlarged portion 24c having a large enlarged width, and a portion on the side of the general inner diameter portion 24e above the insertion hole 24 as a narrow portion 24d with a small expanded width. The insertion hole 24 has a symmetrical configuration with respect to the straight line T1 in a plan view (viewed in the axial direction of the shift drum 11).

When the opposite side portions 32b of the ratchet poles 32 are positioned inside the enlarged diameter portions 24b of the insertion holes 24, the pole ratchet mechanism 20 protrudes outward from the reference outer peripheral surface of the shifter body 31, and It becomes possible to engage with the inner peripheral recess 21b (see FIG. 3).
On the other hand, when the opposite side portions 32b of the respective ratchet poles 32 are located inside the general inner diameter portion 24e of the insertion hole 24, they slide on the inner peripheral surface of the general inner diameter portion 24e and resist the urging force of the urging plunger 33. Then, the displacement toward the inner peripheral side of the shifter eliminates the amount of protrusion from the reference outer peripheral surface of the shifter body 31 at the opposite side 32b of the ratchet pole 32, and the engagement with the inner periphery of the drum center 21 becomes impossible (FIG. 7). reference).

Further, when the shifter assembly 22 is in the initial rotation position, the pole ratchet mechanism 20 rotates in both directions together with the drum center 21 by simultaneously engaging each ratchet pole 32 with one of the inner peripheral recesses 21b. (See FIG. 3).
On the other hand, when the shifter assembly 22 is rotated in one direction from the initial rotation position together with the drum center 21 by the output from the electric motor 15, the inner periphery of the drum center 21 is rotated when the shifter assembly 22 is rotated in the opposite direction. The ratchet pawl 32 that engages with the guide plate 23 is slidably contacted with the inner periphery of the insertion hole 24 of the guide plate 23 and displaced toward the inner periphery of the shifter, thereby allowing the shifter assembly 22 to rotate in the opposite direction with respect to the drum center 21. (See FIG. 7).

  That is, after the shifter assembly 22 is rotated in one direction, only the shifter assembly 22 can rotate in the reverse direction (can be idled) in cooperation with the guide plate 23. Accordingly, only the shifter assembly 22 can return to the initial rotation position with respect to the drum center 21 and the shift drum 11 whose rotation is restricted by the drum stopper 29 after the rotation in the one direction.

  Such a shifter assembly 22 repeats forward and reverse reciprocation at a predetermined angle, whereby the drum center 21 and the shift drum 11 are intermittently fed in the forward and reverse directions. The angle at which the shift drum 11 rotates at a time by this intermittent feed corresponds to the angle at which the shift stage of the transmission 4 is shifted up or down by one stage.

  Here, as shown in FIG. 8, the shifter assembly 22 and the guide plate 23 are integrated with the shift drum 11 and the drum center 21 previously supported by the crankcase 2 using a predetermined assembly jig 40. It is assembled in a held state.

  Referring also to FIG. 9, the assembling jig 40 is formed by cutting out, for example, a cylindrical member (circular steel pipe or the like) made of, for example, a steel plate having the same diameter as the reference outer peripheral surface of the shifter body 31 in a C shape in the axial direction. (Or a spring steel plate or the like having a predetermined shape is formed in a C shape), fitted to the outer periphery of the shifter assembly 22 from the front, and each ratchet pole 32 against the urging force of each urging plunger 33. The shifter assembly 22 and the guide are fitted to the inner periphery of the insertion hole 24 of the guide plate 23 while being displaced toward the inner periphery of the shifter and elastically deformed toward the outer periphery of the shifter by the biasing force of each biasing plunger 33. The plate 23 is held in an integrated sub-assembly state (small assembly state).

A U-shaped notch 41 that opens rearward and a protrusion 42 that protrudes forward are formed in front of and behind the opening 43 on the outer periphery of the assembling jig 40 in the radial direction. .
In the cutout portion 41 of the assembly jig 40, the convex portion 24a of the insertion hole 24 of the guide plate 23 can enter and exit from the rear along the axial direction. In the small assembly state, the front surface of the convex portion 24a is cut. It is possible to contact the bottom surface of the notch 41 and the rear surface of the convex portion 24 a can contact the front surface of the lower outer peripheral portion 34 a of the base portion 34 of the shifter body 31.

  The assembling jig 40 has substantially the same circumferential length on both sides of the notch 41, and covers and holds half or more (180 degrees or more) of the outer periphery of the shifter assembly 22. Further, the assembly jig 40 can hold the guide plate 23 in a well-balanced state by pressing both ends of the open portion 43 side against the inner periphery of the narrow portion 24d of the enlarged diameter portion 24b of the guide plate 23 in a small assembly state. The assembling jig 40 is separated from the inner periphery of the enlarged portion 24c of the enlarged diameter portion 24b.

Next, a procedure for assembling the shifter assembly 22 and the guide plate 23 to the drum center 21 and the crankcase 2 will be described.
First, as shown in FIG. 10A, the shifter assembly 22 is caused to face the insertion hole 24 of the guide plate 23. At this time, the upper outer peripheral portion 36 a of the arm portion 36 of the shifter body 31 overlaps with the general inner diameter portion 24 e of the insertion hole 24 of the guide plate 23 from the front, and the lower outer peripheral portion 34 a of the base portion 34 of the shifter main body 31 is the guide plate 23. Since the protrusion 24a overlaps with the rear from the rear, when assembling the shifter assembly 22 and the guide plate 23, work is performed with the guide plate 23 inclined with respect to the shifter assembly 22, as shown by the broken line in the figure. Just do it. At this time, the inner edge portion of the general inner diameter portion 24e overlaps the upper outer edge portion of the base portion 34 from the front.

  Next, in a state where each ratchet pole 32 is displaced toward the inner peripheral side of the shifter against the urging force of the urging plunger 33, the assembling jig 40 is fitted to the outer periphery of the shifter assembly 22 from the front (axially outer side). . At this time, the assembly jig 40 is elastically deformed to the outer peripheral side by the urging force of the urging plunger 33, so that both end portions on the open portion 43 side are pressed against the inner periphery of the narrow portion 24d of the enlarged diameter portion 24b. Mating.

  Further, when the convex portion 24a of the guide plate 23 enters the notch 41 of the assembling jig 40 from the rear (inner side in the axial direction), the relative rotational position thereof is defined, and the bottom of the notch 41 The convex portion 24a is sandwiched between the outer periphery of the shifter body 31 and the relative positions in the axial direction of the shifter assembly 22, the guide plate 23, and the assembly jig 40 are defined. As a result, the shifter assembly 22 and the guide plate 23 become a shifter subassembly that is integrally held via the assembly jig 40.

  Next, as shown in FIG. 10 (b), the shifter assembly is arranged by disposing the shifter assembly in front of a predetermined assembly position and inserting the rotation shaft 25 a into the through hole 37 of the shifter body 31. The center positions of the shaft 22 with respect to the drum center 21 and the shift drum 11 are defined. In this state, the shifter assembly 22 is moved into the internal space K by gripping a relatively large guide plate 23 and pushing it backward. Let it come. At this time, since the upper and lower sides of the insertion hole 24 are in contact with the upper and lower sides of the shifter assembly 22, the shifter assembly 22 can be pushed into the drum center 21 with a good balance.

  Then, by fixing the guide plate 23 to the crankcase 2, the forward movement of the shifter assembly 22 (movement in the removal direction from the drum center 21) is restricted by the convex portion 24 a, and the guide plate 23 and A relative rotational position of the shifter assembly 22 around the axis with respect to the drum center 21 and the shift drum 11 is defined.

  At this time, the shifter assembly 22 is in the initial rotation position. From this state, as shown in FIG. 10C, each ratchet pole is gripped by grasping the protrusion 42 and pulling the assembly jig 40 forward. 32 can be displaced toward the outer peripheral side, and these are appropriately engaged with the inner peripheral recess 21 b on the inner periphery of the drum center 21. Thereby, the assembly of the shifter assembly 22 and the guide plate 23 to the drum center 21 and the crankcase 2 is completed.

  As described above, the pole ratchet assembling structure in the above embodiment has the drum center 21 that is coaxially and integrally rotatable at one end portion of the shift drum 11 supported by the crankcase 2, and the axial direction of the drum center 21. A shifter assembly 22 that faces the inside space K that opens to the outside, and a guide plate 23 that has an insertion hole 24 that faces the shifter assembly 22 and is fixed to the crankcase 2, A shifter body 31 that is coaxial and relatively rotatable with respect to the drum center 21, at least a pair of ratchet poles 32 assembled to the shifter body 31, and a biasing plunger 33 that biases each ratchet pole 32 toward the outer periphery of the shifter When the shifter assembly 22 is at the predetermined initial rotation position, The rotation in both directions with respect to the center 21 is restricted by the displacement of the at least one ratchet pole 32 toward the outer periphery of the shifter and the engagement with the inner periphery of the drum center 21, and the shifter assembly 22 rotates together with the drum center 21. When the shifter assembly 22 is rotated in one direction from the initial position, the ratchet pole 32 that engages with the inner periphery of the drum center 21 when the shifter assembly 22 rotates in the reverse direction is in sliding contact with the inner periphery of the insertion hole 24 of the guide plate 23. In the assembly structure of the pole ratchet mechanism 20 in which the shifter assembly 22 is allowed to rotate in the reverse direction by being displaced toward the inner periphery of the shifter and releasing the engagement with the inner periphery of the drum center 21, The ratchet poles 32 are displaced to the inner peripheral side of the shifter against the urging force of the urging plunger 33 by being fitted to the outer periphery of the body 22 and An assembly jig 40 is provided which is elastically deformed toward the outer periphery of the shifter by the urging force of the urging plunger 33 and fits into the inner periphery of the insertion hole 24 of the guide plate 23, and the guide plate 23 projects to the inner periphery of the insertion hole 24. 31 has a convex portion 24a that comes into contact with the lower outer peripheral portion 34a from the outer side in the axial direction, and the assembling jig 40 has a notch portion 41 that allows the convex portion 24a to enter and exit from the inner side in the axial direction. The assembly jig 40 is fitted from the outside in the axial direction to the outer periphery of the shifter assembly 22 and the inner periphery of the insertion hole 24 while facing the insertion hole 24 of the guide plate 23, and the bottom of the notch 41 and the shifter body 31. In a state in which the convex portion 24a is sandwiched between the lower outer peripheral portion 34a of the base plate and the shifter assembly 22 and the guide plate 23 are integrally held via the assembly jig 40, These are characterized by being assembled to the drum center 21 and the crankcase 2.

  According to this configuration, the shifter assembly 22 having relatively small parts is integrally held with the relatively large guide plate 23 using the assembly jig 40 having a simple configuration, so that the shifter assembly 22 and The guide plate 23 can be easily assembled to the drum center 21 and the crankcase 2.

  In the pole ratchet assembling structure, the assembling jig 40 has a C-shape as viewed in the axial direction covering at least a half circumference of the outer periphery of the shifter assembly 22, and a notch 41 is formed in the circumferential intermediate portion. In addition, on both sides of the convex portion 24a of the insertion hole 24 of the guide plate 23, the enlarged diameter portions 24b that can be fitted to both sides in the circumferential direction of the assembly jig 40 are formed, so that the shifter assembly 22 is well balanced. Can be retained.

  Furthermore, in the above-described pole ratchet assembly structure, both of the enlarged diameter portions 24b have an enlarged portion 24c having a large expanded width and a narrow portion 24d having a small expanded width, and an assembly jig 40 is provided in the narrow portion 24d. By fitting the both sides in the circumferential direction, the thickness of the assembling jig 40 can be suppressed, and this can be fitted to the outer periphery of the shifter assembly 22 and to the inner periphery of the guide plate 23. .

  The present invention is not limited to the above-described embodiment. For example, as shown in FIG. 11, both the enlarged diameter portions 124b of the insertion holes 24 of the guide plate 23 have a constant expanded width equivalent to that of the enlarged portion 24c. The assembly jig 140 having the entire or part of the thickness increased with respect to the assembly jig 40 may be fitted in the enlarged diameter portion 124b. The assembly jig 140 covers and holds more than half of the outer periphery of the shifter assembly 22 and is elastically deformed by the urging force of each ratchet pole 32. The assembly jig 140 is rigid while being thick with respect to the assembly jig 40. It is comprised with the material (for example, aluminum or resin) which restrained.

In addition, when the shifter assembly 22 faces the drum center 21, the assembly jigs 40 and 140 together with the shifter assembly 22 enter the internal space K of the drum center 21 according to the plate thickness of the assembly jigs 40 and 140. The shifter assembly 22 may be extracted together with the guide plate 23 without entering the inner space K, for example, by the assembly jigs 40, 140 riding on the peripheral edge of the opening of the drum center 21. The structure which faces the drum center 21 may be sufficient.
And the structure in the said Example is an example of this invention, and it cannot be overemphasized that a various change is possible in the range which does not deviate from the summary of the said invention.

It is a front view of the engine in the Example of this invention. It is AA sectional drawing in FIG. It is a front view of the change mechanism of the transmission of the engine. FIG. 3 is a developed sectional view corresponding to FIG. 2 of the change mechanism. It is a disassembled perspective view of the shifter assembly of the change mechanism. It is sectional drawing orthogonal to the axis line in the ratchet pole assembly position of the said shifter assembly. It is a front view equivalent to FIG. 3 which shows the operating state of the said change mechanism. It is a front view of the state which hold | maintained the said shifter assembly body and the guide plate integrally with the assembly jig | tool. It is a perspective view of the said assembly jig. It is operation | movement explanatory drawing which showed the procedure at the time of assembling | attaching the shifter assembly and guide plate hold | maintained with the said assembly jig | tool to a drum center and a crankcase in order of (a)-(c). It is a front view equivalent to FIG. 8 which shows the modification of the said Example.

Explanation of symbols

1 Engine 2 Crankcase (case body)
4 Transmission 10 Change Mechanism 11 Shift Drum 20 Pole Ratchet Mechanism 21 Drum Center K Internal Space 22 Shifter Assembly 23 Guide Plate 24 Insertion Hole 24a Protrusion 24b Expanding Diameter 24c Expanding 24d Narrow 31 Shifter Main Body 32 Ratchet Pole 33 Energizing Plunger (biasing means)
34a Lower outer periphery (outer periphery)
40 Assembly jig 41 Notch

Claims (3)

A drum center that is coaxially and integrally rotatable at one end of a shift drum supported by the case body, a shifter assembly that faces an internal space that opens outward in the axial direction of the drum center, and the shifter assembly faces A guide plate having an insertion hole and fixed to the case body,
The shifter assembly is a shifter body coaxially and relatively rotatable with respect to the drum center, at least a pair of ratchet poles assembled to the shifter body, and biasing means for biasing each ratchet pole toward the shifter outer peripheral side And
When the shifter assembly is at a predetermined rotation initial position, the rotation in both directions with respect to the drum center is caused by the displacement of at least one ratchet pole toward the outer periphery of the shifter and engagement with the inner periphery of the drum center. Regulated,
When the shifter assembly rotates together with the drum center in one direction from the rotation initial position, the ratchet pawl slidably contacts the inner periphery of the insertion hole of the guide plate.
The ratchet poles are fitted to the outer periphery of the shifter assembly and are displaced toward the inner peripheral side of the shifter against the biasing force of the biasing means, and elastically deformed to the outer periphery of the shifter by the biasing force of the biasing means. An assembly jig for fitting to the inner periphery of the insertion hole of the guide plate;
The guide plate has a projection that protrudes to the inner periphery of the insertion hole and abuts the outer periphery of the shifter body from the outside in the axial direction, and the assembly jig cuts the projection to enter and exit from the inner side in the axial direction. Has a notch,
With the shifter assembly facing the insertion hole of the guide plate, the assembly jig is fitted to the outer periphery of the shifter assembly and the inner periphery of the insertion hole from the outside in the axial direction, and the bottom of the notch and the shifter body A pole ratchet characterized in that the convex part is sandwiched between the outer peripheral part and the shifter assembly and the guide plate are integrally held via the assembly jig, and these are assembled to the drum center and the case body. Assembly structure. The assembly jig has a C-shape as viewed in the axial direction covering at least a half circumference of the outer periphery of the shifter assembly, the cutout portion is formed in the middle portion in the circumferential direction, and both sides of the convex portion in the insertion hole of the guide plate The pole ratchet assembling structure according to claim 1, wherein an enlarged-diameter portion in which both side portions in the circumferential direction of the assembling jig can be fitted is formed. The both enlarged diameter parts have an enlarged part having a large enlarged width and a narrow part having a small enlarged width, and both side portions in the circumferential direction of the assembly jig are fitted in the narrow part, respectively. The pole ratchet assembling structure according to claim 2.

Images