JP5425741B2 - Lubrication structure and multi-stage transmission using the lubrication structure - Google Patents

Description

  The present invention relates to a lubricating structure that introduces lubricating oil into an inner hollow portion of a shaft member that is rotatably supported, and a multi-stage transmission that uses the lubricating structure.

In the case where the cylindrical shaft member is rotatably supported by the bearing portion of the case via the bearing, the end of the shaft member is covered with a case-side lid, and the inside of the shaft member is passed through the oil passage in the lid. Generally, lubricating oil is introduced into the hollow portion.
However, various mechanisms may be attached to both ends of the shaft member to form an oil passage (see, for example, Patent Document 1).

Japanese Patent Application No. 2009-47269

  Patent Document 1 is an invention relating to a lubrication structure for a multi-stage transmission previously filed by the same applicant, and the multi-stage transmission disclosed in Patent Document 1 includes a gear integrated with a main gear shaft and a counter gear shaft. A gear that is rotatably supported by a shaft is always meshed, and a gear that effectively acts on the counter gear shaft is selected by an engagement switching mechanism in the counter gear shaft to perform a shift.

The counter gear shaft provided with an engagement switching mechanism is provided with a driving sprocket at one end and a shift mechanism for shifting at the other end. Therefore, lubricating oil is introduced from the peripheral surface of the counter gear shaft.
That is, a lubricating oil introduction path is formed in an annular oil seal and a cylindrical collar member inserted into a bearing opening of a bearing of a case that supports a counter gear shaft via a bearing. The oil seal and the introduction path of the cylindrical collar member communicate with each other through an oil passage opening opened on the peripheral surface and an introduction hole penetrating the inside and outside of the counter gear shaft.

  A cylindrical collar member is inserted between the inner peripheral surface of the oil seal and the outer peripheral surface of the counter gear shaft. An inner peripheral annular opening opened on the inner peripheral surface of the oil seal and a communication hole of the cylindrical collar member are provided. An inner elastic lip that protrudes from the inner peripheral edge of the oil seal in the axial direction toward the central axis toward the outer side in the oblique axis direction is provided in an annular shape so as to communicate with each other, and the inner elastic lip is a cylindrical collar. The lubricating oil that is pressed by the member and guided from the inner peripheral annular opening to the communication hole is prevented.

Therefore, the inner diameter of the annular inner elastic lip portion of the oil seal is smaller than the outer diameter of the cylindrical collar member when no external force is applied.
Therefore, when the cylindrical collar member is inserted between the inner peripheral surface of the annular oil seal that is pre-inserted in the bearing opening and the outer peripheral surface of the counter gear shaft, the axial inner end surface of the cylindrical collar member The outer peripheral edge abuts on the lip tip of the inner elastic lip projecting from the inner peripheral edge on the inner side in the axial direction of the oil seal toward the outer side in the oblique axis direction, and the inner elastic lip is turned over, The elastic lip portion may remain in a state where it is turned back without being elastically restored to a state in which the elastic lip portion protrudes toward the outer side in the oblique axis direction.

  When the inner elastic lip portion is turned over, the pressure of the lubricating oil guided from the inner peripheral annular opening of the oil seal to the communication hole of the cylindrical collar member acts in the direction of further turning the inner elastic lip portion, and the cylinder There is a possibility that the lubricating oil leaks by forming a gap with the outer peripheral surface of the collar member, and the lubricating oil is not sufficiently supplied to the inner hollow portion of the counter gear shaft.

  Therefore, conventionally, when the inner elastic lip portion is turned over by inserting the cylindrical collar member, the cylindrical collar member is moved back and forth in the axial direction several times to return the inner elastic lip portion to its original state. It was necessary to repeat trials so that the cylindrical collar member was assembled at a predetermined position in the state, and the assembly work was not easy.

  The present invention has been made in view of the above point, and the object of the present invention is to provide an oil seal and a cylindrical collar member between the bearing opening of the case and the shaft member, and to prevent leakage of lubricating oil. It is in the point which provides the lubrication structure which can be assembled | attached easily to a state and can introduce | transduce sufficient lubricating oil to the inner side hollow part of a shaft member.

In order to achieve the above object, the invention according to claim 1
An annular oil seal (40) is fitted inside the inner peripheral surface of the bearing opening (1e) of the case (1) that rotatably supports the shaft member (12),
A cylindrical collar member (33) is inserted between the inner peripheral surface of the oil seal (40) and the outer peripheral surface of the shaft member (12),
The cylindrical collar member (33) is provided with a communication hole (33x) communicating from the outer peripheral surface to the inner peripheral surface,
The shaft member (12) has an oil introduction hole (12x) communicating with the hollow portion inside the shaft member at a position facing the communication hole (33x) of the cylindrical collar member (33),
The oil seal (40) includes an outer peripheral annular opening (40xo) that opens in the circumferential direction on the outer peripheral surface and an inner peripheral annular opening (40xi) that opens in the circumferential direction on the inner peripheral surface. ) And an annular elastic lip portion (41i) which is provided obliquely inward in the axial direction from the inner peripheral edge of the axially outer side to the central axis side, and from the inner peripheral edge of the axially inner side to the central axis side An inner elastic lip portion (42i) protruding toward the outer side in the oblique axis direction is provided in an annular shape,
The outer peripheral annular opening (40xo) faces the oil passage opening (1x) on the inner peripheral surface of the bearing opening (1e),
The inner annular opening (40xi) faces the communication hole (33x) of the cylindrical collar member (33), and the inner elastic lip portion (42i) is an axially inner end of the cylindrical collar member (33). In a lubricating structure configured to guide the lubricating oil from the inner annular opening (40xi) to the communication hole (33x) by elastically pressing the outer peripheral surface of the portion (33e) ,
The minimum inner diameter when no external force is applied to the oil seal (40) is the inner diameter (ds) formed by the annular elastic lip portion (41i) and the inner elastic lip portion (42i),
The cylindrical collar member (33) is a lubrication structure, wherein the outer diameter (d2) smaller of the axial inner end as compared to the maximum outer diameter (d1) (33e).

The invention according to claim 2 is the lubricating structure according to claim 1,
The tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the outer diameter (d3) of the tip edge of the tapered surface (33t) Is smaller than the inner diameter (ds) of the inner elastic lip (42i) of the oil seal (40).

The invention described in claim 3
A plurality of drive gears (m1 to m6) and driven gears (n1 to n6) are respectively mounted on parallel gear shafts (12) that are rotatably mounted via a pair of bearings (7L, 7R) in the case (1). Is always supported in mesh with each gear stage, and a plurality of one of the drive gears (m1 to m6) and the driven gears (n1 to n6) are fixed to the gear shaft (11), and the other plurality of gears. An engagement switching mechanism that switches the engagement between the gear shaft and each gear between the gear and the gear shaft (12) for each gear is provided, and the engagement switching mechanism is driven by a shift drive mechanism to perform a shift. Machine,
The engagement switching mechanism is
Engagement portions (31) provided with engagement surfaces in the circumferential direction at a plurality of locations in the circumferential direction of the inner circumferential surface of each gear (n1 to n6);
A swinging claw member (R) that engages and disengages the engagement surface of the engagement portion (31) with one end pivotally supported by the gear shaft (12),
A pin member (23) in contact with the other end of the front swinging claw member (R) from the inside in the radial direction;
A plurality of sliding contact surfaces which are axially moved by being fitted into cam guide grooves (12g) cut in the axial direction on the inner peripheral surface of the hollow portion of the gear shaft (12) and slidably contact the pin member (23). The cam surfaces (v1 to v6) are formed at required locations in the axial direction, and include a plurality of cam rods (C) that actuate the swing claw member (R) via the pin member (23) by movement,
The speed change drive mechanism is provided with a multistage shift rod (51) that is inserted into the hollow central shaft of the gear shaft (12) inside the cam rod (C) and moves the cam rod (C) by axial movement. In the transmission,
An annular oil seal (40) is fitted in the inner peripheral surface of the bearing opening (1e) of the case (1) that rotatably supports the gear shaft (12),
A cylindrical collar member (33) is inserted between the inner peripheral surface of the oil seal (40) and the outer peripheral surface of the gear shaft (12),
The cylindrical collar member (33) is provided with a communication hole (33x) communicating from the outer peripheral surface to the inner peripheral surface,
The gear shaft (12) has an oil introduction hole (12x) communicating with the hollow portion inside the gear shaft at a position facing the communication hole (33x) of the cylindrical collar member (33),
The oil seal (40) includes an outer peripheral annular opening (40xo) that opens in the circumferential direction on the outer peripheral surface and an inner peripheral annular opening (40xi) that opens in the circumferential direction on the inner peripheral surface. ) And an annular elastic lip portion (41i) which is provided obliquely inward in the axial direction from the inner peripheral edge of the axially outer side to the central axis side, and from the inner peripheral edge of the axially inner side to the central axis side An inner elastic lip portion (42i) protruding toward the outer side in the oblique axis direction is provided in an annular shape,
The outer peripheral annular opening (40xo) faces the oil passage opening (1x) on the inner peripheral surface of the bearing opening (1e),
The inner annular opening (40xi) faces the communication hole (33x) of the cylindrical collar member (33), and the inner elastic lip portion (42i) is an axially inner end of the cylindrical collar member (33). A lubricating structure configured to guide the lubricating oil from the inner annular opening (40xi) to the communication hole (33x) by elastically pressing the outer peripheral surface of the portion (33e) ,
The minimum inner diameter when no external force is applied to the oil seal (40) is the inner diameter (ds) formed by the annular elastic lip portion (41i) and the inner elastic lip portion (42i),
The cylindrical collar member (33) is a multi-speed transmission, wherein the outer diameter (d2) smaller of the axial inner end as compared to the maximum outer diameter (d1) (33e).

According to a fourth aspect of the present invention, in the multi-stage transmission according to the third aspect,
The tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the tip outer diameter (d3) is the above-mentioned of the oil seal (40). It is smaller than the inner diameter (ds) of the inner elastic lip part (42i).

The invention according to claim 5 is the multi-stage transmission according to claim 3 or 4, wherein
The gear shaft (12) provided with the engagement switching mechanism is an output shaft (12),
A shaft end protruding outward from the journal portion (12j) to which the inner race (7Li) of the bearing (7L) in the output shaft (12) is fitted is a male screw (12e) formed at the outermost end. A spline groove (12s) formed on the inner side of the male screw (12e) and an outer peripheral groove (12f) formed in the circumferential direction at the boundary between the male screw (12e) of the spline groove (12s). ,
The cylindrical collar member (33) externally fitted to the output shaft (12) is in contact with the inner race (7Li) fitted to the journal portion (12j),
The output sprocket (32) that is spline-fitted into the spline groove (12s) presses the cylindrical collar member (33) with a disc spring (34) interposed therebetween,
The half cotter (35) fitted in the outer circumferential groove (12f) receives the output sprocket (32),
An annular retainer (36) comprising an outer peripheral wall and an annular side wall facing the outer peripheral surface and the outer surface of the half cotter (35) is externally fitted to the half cotter (35), and the half cotter (35) is attached. Hold and
A nut member (37) screwed into the male screw (12e) is configured to sandwich the annular retainer (36) between the half cotter (35).

  According to the lubricating structure of claim 1, the annular oil seal (40) fitted into the inner peripheral surface of the bearing opening (1e) of the case (1) for rotatably supporting the shaft member (12) is provided. The cylindrical collar member (33) inserted between the inner peripheral surface and the outer peripheral surface of the shaft member (12) has an outer diameter (33e) in the axial direction compared to the maximum outer diameter (d1) ( Since d2) is made smaller, an annular inner elastic lip portion (42i) on the axially inner side of the oil seal (40) having an inner diameter that elastically changes smaller than the maximum outer diameter (d1) of the cylindrical collar member (33). The inner diameter (ds) of the cylindrical collar member (33) can be suitably smaller than the outer diameter (d2) of the axially inner end (33e) of the cylindrical collar member (33). Even if the annular tip edge of the inner elastic lip part (42i) that protrudes outward in the oblique axis direction is slightly turned upside down, when the insertion is finished, the turnover is eliminated by the elasticity, and the inner side lip part is inclined toward the center axis side. Axially outward With a normal posture facing, it is elastically pressed against the outer peripheral surface of the axially inner end (33e) of the cylindrical collar member (33).

  The inner elastic lip portion (42i) is elastically pressed against the outer peripheral surface of the axially inner end portion (33e) of the cylindrical collar member (33) in a normal posture facing the outer side in the axial direction toward the central axis side. Therefore, the pressure of the lubricating oil guided from the inner circumferential annular opening (40xi) of the oil seal (40) to the communication hole (33x) of the cylindrical collar member (33) is reduced by the inner elastic lip portion (42i) of the cylindrical collar member ( 33) is further overlapped in the direction in which it is elastically press-contacted, and the gap between the outer peripheral surface of the cylindrical collar member (33) is securely closed to prevent leakage of the lubricating oil, and the shaft member (12 ) Can be sufficiently supplied to the inner hollow portion.

  In this way, the cylindrical collar member (33) can be inserted and retracted once and again between the inner peripheral surface of the annular oil seal (40) and the outer peripheral surface of the shaft member (12), The oil seal (40) and the cylindrical collar member (33) are easily assembled in a normal state between the bearing opening (1e) of the case (1) and the shaft member (12) so that the leakage of the lubricating oil can be prevented. be able to.

  According to the lubricating structure of the second aspect, the tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the tapered surface (33t) Since the outer diameter (d3) of the tip edge is smaller than the inner diameter (ds) of the inner elastic lip part (42i) of the oil seal (40), when inserting the cylindrical collar member (33), the axis direction is oblique to the center axis side. The annular leading edge of the inner elastic lip portion (42i) facing outwards expands while sliding in contact with the tapered surface of the cylindrical collar member (33), and the axially inner end portion (33e) of the axial inner end portion (33e) is not turned over. The inner elastic lip (42i) is elastically applied to the outer peripheral surface of the inner end (33e) in the axial direction of the cylindrical collar member (33) with the posture toward the outer side in the oblique axial direction toward the central axis. Can be pressed against each other and can be assembled more smoothly.

  According to the multi-stage transmission of claim 3, a plurality of drive gears (m1) are respectively connected to the mutually parallel gear shafts (12) rotatably installed in the case (1) via a pair of bearings (7L, 7R). M6) and driven gears (n1 to n6) are always supported in mesh at every gear position, and the engagement switching mechanism is driven by the gear shift drive mechanism to perform gear shift. A cylindrical collar member (33) inserted between the inner peripheral surface of the annular oil seal (40) fitted in the inner peripheral surface of the bearing opening (1e) and the outer peripheral surface of the gear shaft (12) is provided. Since the outer diameter (d2) of the axially inner end (33e) is smaller than the maximum outer diameter (d1), the elastic change is smaller than the maximum outer diameter (d1) of the cylindrical collar member (33). The inner diameter (ds) of the annular inner elastic lip portion (42i) of the oil seal (40) having an inner diameter is the outer diameter of the axial inner end (33e) of the cylindrical collar member (33) ( d2) Moderately smaller When the cylindrical collar member (33) is inserted, even if the annular front edge of the inner elastic lip portion (42i) protruding toward the outer side in the oblique axis direction on the central axis side is slightly turned up, When the insertion is completed, the curl is eliminated by elasticity, and the outer peripheral surface of the axially inner end (33e) of the cylindrical collar member (33) is elastically oriented in a normal posture facing the outer side in the axial direction toward the central axis. Press contact.

  Even if the pressure contact by the elastic force of the inner elastic lip (42i) to the cylindrical collar member (33) is weak, the communication hole of the cylindrical collar member (33) from the inner annular opening (40xi) of the oil seal (40) The pressure of the lubricating oil guided to (33x) acts in the direction in which the inner elastic lip portion (42i) facing the outer side in the oblique axial direction toward the central axis is pressed against the cylindrical collar member (33), and the cylindrical collar member The gap between the outer peripheral surface and the outer peripheral surface can be reliably closed to prevent the lubricating oil from leaking, and the lubricating oil can be sufficiently supplied to the inner hollow portion of the shaft member.

  In this way, the cylindrical collar member (33) can be inserted and retracted once and again between the inner peripheral surface of the annular oil seal (40) and the outer peripheral surface of the shaft member (12), The oil seal (40) and the cylindrical collar member (33) are easily assembled in a normal state between the bearing opening (1e) of the case (1) and the shaft member (12) so that the leakage of the lubricating oil can be prevented. This facilitates the assembly work of the multi-stage transmission.

  According to the multi-stage transmission of the fourth aspect, the tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the tip outer diameter (d3 ) Is smaller than the inner diameter (ds) of the inner elastic lip portion (42i) of the oil seal (40), so that when inserting the cylindrical collar member (33), the inner elastic lip is directed obliquely outward in the axial direction toward the central axis. The annular tip edge of the portion (42i) expands while sliding in contact with the tapered surface of the cylindrical collar member (33), and reaches the outer peripheral surface of the axially inner end portion (33e) without being turned over. The elastic lip portion (42i) can be elastically pressed against the outer peripheral surface of the axially inner end portion (33e) of the cylindrical collar member (33) while maintaining the posture directed obliquely outward in the axial direction toward the central axis side. Assembly can be performed more smoothly.

  According to the multi-stage transmission of claim 5, the output shaft (12) is externally fitted to the inner race (7Li) of the bearing (7L) fitted to the journal portion (12j) at the shaft end of the output shaft (12). The cylindrical collar member (33) abuts, and the output sprocket (32) spline-fitted into the spline groove (12s) presses the cylindrical collar member (33) with a disc spring (34) sandwiched between them, and the outer circumferential groove ( The half cotter (35) fitted to 12f) receives the output sprocket (32), and an annular retainer (36) consisting of an outer peripheral surface facing the outer peripheral surface of the half cotter (35), an outer peripheral surface, and an annular side wall. A nut member (37) that is externally fitted to the half cotter (35) to hold the half cotter (35) and is screwed onto the male screw (12e) is connected to the annular retainer (36) with the half cotter (35). Since the output sprocket (32) is spline-fitted to the output shaft (12), the disc spring (34) is interposed between the cylindrical collar member (33) and the half cotter (35). Pinch Therefore, the output sprocket (32) is always located within the required axial range while absorbing the force component that swings in the axial direction, thereby enabling stable power transmission.

1 is a right side view of a partially omitted internal combustion engine incorporating a multi-stage transmission according to an embodiment of the present invention. It is sectional drawing (II-II sectional view taken on the line of FIG. 1) of a multistage transmission. It is sectional drawing (III-III sectional view taken on the line of FIG. 5, FIG. 6) which shows a counter gear shaft and the structure around it. It is another sectional view (IV-IV line sectional view of Drawing 5 and Drawing 6) showing a counter gear axis and the structure around it. It is the VV sectional view taken on the line of FIG. 3, FIG. It is the VI-VI sectional view taken on the line of FIG. It is a disassembled perspective view of a shift rod and a lost motion mechanism. It is a disassembled perspective view of the state which assembled | attached the lost motion mechanism to the shift rod, and a cam rod. It is a disassembled perspective view of a part of a counter gear shaft, a pin member, and a spring. FIG. 10 is a left side view of the counter gear shaft (viewed in the direction of arrow X in FIG. 9). It is a disassembled perspective view of a rocking claw member, a spindle pin, a pin member, and a spring. It is a perspective view which shows the state which assembled | attached a part of speed-change drive mechanism and the engagement means to the counter gear shaft. FIG. 13 is a perspective view showing a state in which one bearing collar member is packaged on the counter gear shaft in the state shown in FIG. 12. It is explanatory drawing which shows 1 state of the process to shift up. It is a top view of lower engine case 1L. It is the same side view. FIG. 17 is an enlarged cross-sectional view in the vicinity of the left bearing portion of the counter gear shaft (cross-sectional view taken along line XVII-XVII in FIG. 16). It is a disassembled expanded sectional view of the left side bearing part vicinity of the counter gear shaft. It is a disassembled expanded sectional view of an oil seal and a cylindrical collar member. It is sectional drawing to which the principal part of FIG. 17 which shows the lubricating structure of a counter gear shaft was expanded. It is sectional drawing which expanded a part of FIG. 20 further.

An embodiment according to the present invention will be described below with reference to FIGS.
A multi-stage transmission 10 according to the present embodiment is configured to be incorporated in an internal combustion engine mounted on a motorcycle.
FIG. 1 is a right side view of the internal combustion engine E with a part omitted, and FIG. 2 is a cross-sectional view of the multi-stage transmission 10 (cross-sectional view taken along the line II-II in FIG. 1), as shown in FIGS. In addition, the multi-stage transmission 10 is provided in an engine case 1 common to the internal combustion engine.

As shown in FIG. 1 which is a right side view of the engine case 1, the engine case 1 is formed by combining the upper engine case 1U and the lower engine case 1L which are divided vertically with a crankshaft 6 directed in the horizontal direction as a boundary. The engine case 1 is integrally formed with a transmission chamber 2, and the main gear shaft 11 and the counter gear shaft 12 of the multi-stage transmission 10 are oriented in the horizontal direction in parallel to each other in the transmission chamber 2. Thus, it is pivotally supported.
The upper engine case 1U and the lower engine case 1L are united by supporting the crankshaft 6 and the counter gear shaft 12 at the same height as the crankshaft 6 at a high position in the transmission chamber 2 so as to sandwich from above and below. .

  Referring to FIG. 2, a transmission chamber 2 is formed in the rear half of the combined engine case 1, and the engine case 1 supports the left side portions of the main gear shaft 11 and the counter gear shaft 12 in the transmission chamber 2. A large opening of the transmission chamber is formed on the right side, the opening of the transmission chamber is covered with a bearing lid member 8, and the bearing lid member 8 that forms a part of the engine case covers the right side portion of the main gear shaft 11 and the counter gear shaft 12. Pivot.

The main gear shaft 11 is rotatably supported by the side wall of the lower engine case 1L and the bearing lid member 8 via bearings 3L and 3R, and passes through the right bearing 3R and protrudes from the transmission chamber 2 to the right end portion. A multi-plate friction clutch 5 is provided.
On the left side of the friction clutch 5, a primary driven gear 4 to which the rotation of the crankshaft 6 is transmitted is rotatably supported by the main gear shaft 11.
The rotation of the crankshaft of the internal combustion engine is transmitted from the primary driven gear 4 to the main gear shaft 11 via the engaged friction clutch 5.

Referring to FIG. 2, the main gear shaft 11 has a hollow cylindrical shape, and the inside of the hollow is composed of a long large-diameter hole portion 11a having a relatively large inner diameter and a small-diameter hole portion 11b slightly reduced in diameter on the right side. A long push rod 15l is inserted into the large-diameter hole 11a, a short push rod 15s is slidably inserted into the small-diameter hole 11b, and a right end 15lr of the long push rod 15l is inserted into the small-diameter hole 11b. The three balls 16 are sandwiched between the left end of the short push rod 15s.
The ball 16 has an outer diameter in which three small diameter holes 11b enter the same position in the axial direction, and the right end portion 15lr of the long push rod 15l and the left end portion of the short push rod 15s have an annular shape on the opposite end surfaces. A shallow annular groove is formed on each of the three balls 16 so that the three balls 16 can be stably held.

The left end portion of the long push rod 15l passes through the lower engine case 1L to the left and is fitted to the piston 17p of the clutch hydraulic actuator 17.
On the other hand, the right end portion of the short push rod 15s protrudes rightward from the main gear shaft 11 and abuts against the central portion of the pressure plate 5p of the friction clutch 5.

Therefore, when the clutch hydraulic actuator 17 is actuated and the piston 17p pushes the long push rod 15l to the right, the short push rod 15s is pushed through the ball 16, and the pressure plate 5p is made elastic by the clutch spring 5s. Accordingly, the engagement of the friction clutch 5 engaged by the elastic force of the clutch spring 5s can be released by moving the pressure plate 5p to the right.
The three balls 16 serve as thrust bearings and do not transmit the rotation of the short push rod 15s to the long push rod 15l.

  The counter gear shaft 12 is pivotally supported via a bearing 7L sandwiched between both side walls of the upper engine case 1R and the lower engine case 1L, and the right end portion of the counter gear shaft 12 is supported by the bearing lid member 8 via the bearing 7R. It is pivotally supported.

On the main gear shaft 11, a drive transmission gear m group is configured between the left and right bearings 3L, 3R so as to be rotatable integrally with the main gear shaft 11.
A first drive transmission gear m1 is formed integrally with the main gear shaft 11 along the right bearing 3R, and a spline formed between the first drive transmission gear m1 of the main gear shaft 11 and the left bearing 3L is viewed from the right. The second, third, fourth, fifth, and sixth drive transmission gears m2, m3, m4, m5, and m6, whose diameters are sequentially increased to the left, are spline-fitted.

On the other hand, on the counter gear shaft 12, a driven transmission gear n group is rotatably supported via an annular bearing collar member 13 between the left and right bearings 7L and 7R (see FIGS. 3 and 4). .
In the counter gear shaft 12, as shown in FIGS. 3 and 4, the right end bearing collar member 13 is provided through a collar member 14R interposed on the left side of the right bearing 7R and the right side of the left bearing 7L. Between the leftmost bearing collar member 13 packaged via the mounted collar member 14L, five bearing collar members 13 are packaged at equal intervals, and a total of seven bearing collar members 13 are adjacent to each other. The first, second, third, fourth, fifth and sixth driven transmission gears n1, n2, n3, n4, n5 whose diameters are sequentially reduced from right to left so as to straddle between the members 13, 13. n6 is rotatably supported.

  The first, second, third, fourth, fifth, and sixth drive transmission gears m1, m2, m3, m4, m5, and m6 that rotate integrally with the main gear shaft 11 are rotatable on the counter gear shaft 12. The corresponding first, second, third, fourth, fifth and sixth driven transmission gears n1, n2, n3, n4, n5 and n6 are always meshed with each other.

The meshing of the first drive transmission gear m1 and the first driven transmission gear n1 constitutes the first speed with the largest reduction ratio, and the meshing of the sixth drive transmission gear m6 and the sixth driven transmission gear n6 has the smallest reduction ratio. Sixth speed is configured, and during that period, the reduction gear ratio is gradually decreased to form second speed, third speed, fourth speed, and fifth speed.
The counter gear shaft 12 has odd-numbered gears (first, third, and fifth driven gears n1, n3, and n5) with odd-numbered gears and even-numbered gears (second, fourth, and fourth) with even-numbered gears. 6 driven transmission gears n2, n4, n6) are alternately arranged.

  The counter gear shaft 12 having a hollow cylindrical shape is incorporated so that the engagement means 20 that can be engaged with each driven transmission gear n will be described later. A total of eight cam rods C (Cao, Cao, Cae, Cae, Cbo, Cbo, Cbe, Cbe) are formed in the hollow inner peripheral surface of the counter gear shaft 12 and fit into a cam guide groove 12g described later. In addition, they are provided so as to be movable in the axial direction.

  A shift rod 51, which is one component of a speed change drive mechanism 50 that drives the cam rod C to change the speed, is inserted into the hollow center shaft of the counter gear shaft 12, and the movement of the shift rod 51 in the axial direction is lost motion. The cam rod C is moved in the axial direction in conjunction with each other via the mechanisms 52 and 53.

A mechanism for moving the shift rod 51 in the axial direction is provided in the bearing lid member 8.
The movement of the shift rod 51 in the axial direction is linked to the cam rod C in the axial direction via the lost motion mechanisms 52 and 53, and the movement of the cam rod C is changed to each driven speed change by the engaging means 20 incorporated in the counter gear shaft 12. The gear n is selectively engaged with the counter gear shaft 12 for shifting.

The engaging means 20 for selectively engaging the counter gear shaft 12 provided on the counter gear shaft 12 and each driven transmission gear n will be described below.
Referring to FIG. 7, shift rod 51 of transmission drive mechanism 50 has a cylindrical rod shape, and outer peripheral recesses 51a and 51b formed by reducing the diameter in two places on the left and right in the axial direction have a predetermined length. Is formed.
The right end of the shift rod 51 is a male screw end portion 51bb formed with a male screw, and a hexagonal nut portion 51c is formed in front of the male screw end portion 51bb.

The lost motion mechanisms 52 and 53 are assembled to correspond to the left and right outer peripheral recesses 51a and 51b of the shift rod 51, respectively.
The left and right lost motion mechanisms 52, 53 are arranged so as to be symmetrical with respect to each other.

  The left lost motion mechanism 52 has a spring holder 52h into which the shift rod 51 is slidably inserted and is configured by connecting the long holder 52hl and the short holder 52hs, and the inner peripheral surface corresponds to the outer peripheral recess 51a of the shift rod 51. An inner peripheral recess 52ha is formed.

  When the shift rod 51 is passed through the spring holder 52h and the spring holder 52h is positioned in the outer peripheral recess 51a, the inner peripheral recess 52ha of the spring holder 52h and the outer peripheral recess 51a of the shift rod 51 constitute a common space. To do.

A pair of left and right cotters 52c, 52c, which are spring receivers, are fitted to face each other so as to straddle both spaces of the inner peripheral recess 52ha of the spring holder 52h and the outer peripheral recess 51a of the shift rod 51, and shift between the both cotters 52c, 52c. A compression coil spring 52 s wound around the rod 51 is interposed to urge both the cotters 52 c and 52 c in a separating direction.
The cotter 52c has a hollow disk shape in which the inner diameter of the inner peripheral recess 52ha of the spring holder 52h is the outer diameter and the outer diameter of the outer peripheral recess 51a of the shift rod 51 is the inner diameter, and is divided in half for assembly. Yes.

The right lost motion mechanism 53 (spring holder 53h, long holder 53hl, short holder 53hs, inner peripheral recess 53ha, cotter 53c, compression coil spring 53s) has the same structure and is disposed in the outer peripheral recess 51b of the shift rod 51. The
Therefore, when the shift rod 51 moves in the axial direction, the spring holders 52h, 53h move in the axial direction via the compression coil springs 52s, 53s of the left and right lost motion mechanisms 52, 53.

  Eight cam rods C (Cao, Cao, Cae, Cae, Cbo, Cbo) are provided on the outer peripheral surfaces of the spring holders 52h, 53h of the lost motion mechanisms 52, 53 attached to the left and right outer peripheral recesses 51a, 51b of the shift rod 51. , Cbe, Cbe) are in contact with each other at the radiation position (see FIG. 8).

The cam rod C is a rectangular rod-like member having a rectangular cross section and extending in the axial direction. The outer peripheral side opposite to the inner peripheral side contacting the spring holders 52h, 53h forms a cam surface, and the cam surface Grooves v are formed at the required three locations, and a pair of locking claws p that locks either one of the spring holders 52h and 53h from the left and right protrude from the inner peripheral side surface.
Since the cam rod C is a rectangular prismatic member having a simple cross section and a generally simple outer shape, the cam rod C can be easily manufactured.

  The cam rods Cao, Cbo for odd-numbered stages formed with cam grooves v1, v3, v5 at three positions corresponding to the odd-numbered stage gears (first, third, fifth driven transmission gears n1, n3, n5) There are two types of rotation (rotation direction in which force is applied from the driven transmission gear n to the counter gear shaft 12 during acceleration) and reverse rotation (rotation direction in which force is applied from the driven transmission gear n to the counter gear shaft 12 during deceleration). One forward rotation odd-stage cam rod Cao has an engaging claw p that engages with the right spring holder 53h on the inner peripheral side, and the other reverse rotation odd-stage cam rod Cbo has a left spring holder 52h on the inner peripheral side. There is a locking claw p that is locked to (see FIG. 8).

  Similarly, cam rods Cae for even-numbered stages formed at three positions corresponding to even-numbered gears (second, fourth and sixth driven transmission gears n2, n4, n6) with even-numbered gear grooves v2, v4, v6. , Cbe are of two types, forward rotation and reverse rotation, and one forward rotation even-stage cam rod Cae has a locking claw p that locks to the left spring holder 52h on the inner peripheral side, The reverse rotation even stage cam rod Cbe has a locking claw p that locks to the right spring holder 53h on the inner peripheral side surface (see FIG. 8).

  Accordingly, when the shift rod 51 is moved in the axial direction, the positive rotation odd-numbered cam rod Cao and the reverse-rotation even-numbered cam rod Cbe are interlocked with the spring holder 53h via the compression coil spring 53s of the lost motion mechanism 53 on the right side. Then, the reverse rotation odd stage cam rod Cbo and the forward rotation even stage cam rod Cae are interlocked in the axial direction together with the spring holder 52h via the coil spring 52s of the left lost motion mechanism 52.

  As shown in FIG. 8, a cylindrical shift rod operating element 55 is attached to the right end portion on the right side of the nut portion 51c of the shift rod 51 via a ball bearing 56 fitted inside.

  Two ball bearings 56 are connected in the axial direction. The ball bearing 56 is inserted into the right end portion on the right side of the nut portion 51c of the shift rod 51 and is engaged with the nut portion 51c by a nut 57 screwed into the male screw end portion 51bb. It is sandwiched and fastened.

Therefore, the shift rod operator 55 holds the right end portion of the shift rod 51 rotatably.
A pin hole 55h pierced in the diametrical direction is formed in a cylindrical portion extending to the right side from the nut 57 to which the shift rod operating element 55 is screwed, and the shift pin 58 passes through the pin hole 55h.

  The shift pin 58 passes through the shift rod operating element 55 and protrudes only to one side (see FIG. 2). As shown in FIG. 8, the protruding end portion is formed in a shift guide groove G of the shift drum 67 described later. A cylindrical engaging portion 58a that is slidably engaged, and a sliding portion 58b having a rectangular parallelepiped shape is formed between the small diameter cylindrical portion 58c penetrating the shift rod operating element 55 and the engaging portion 58a. Yes.

Referring to FIGS. 1 and 2, the bearing cover member 8 that pivotally supports the right end portions of the main gear shaft 11 and the counter gear shaft 12 via bearings 3R and 7R is disposed coaxially with the counter gear shaft 12 on the right side. A cylindrical guide portion 8g is formed so as to protrude.
The cylindrical guide portion 8g includes a circular hole 8gh through which the shift rod operating element 55 slides, and a lower portion thereof is cut obliquely downward to form a guide long hole 8gl that is elongated in the axial direction.

A support shaft 65 is implanted obliquely below the cylindrical guide portion 8g of the bearing lid member 8, and a cylindrical shift drum 67 is rotatably supported on the support shaft 65 via a bearing 66.
At the same time that the shift rod operator 55 is inserted into the guide long hole 8gl of the cylindrical guide portion 8g, the slide portion 58b having a rectangular parallelepiped shape of the shift pin 58 passing through the shift rod operator 55 is inserted into the guide length of the cylindrical guide portion 8g. The hole 8gl is slidably inserted, and the engaging portion 58a at the end of the shift pin 58 is slidably engaged with the shift guide groove G of the shift drum 67.
The power of a speed change actuator (not shown) such as a speed change motor (or the operating force of manual shift operation) is transmitted to a gear 67g formed on the side edge of the shift drum 67 to sequentially shift the shift drum 67. Rotate to position.

  The shift rod moving mechanism (shift drum 67, shift pin 58, shift rod operating element 55) that moves the shift rod 51 in the axial direction via the shift pin 58 by the rotation of the shift drum 67 is a friction at the right end of the main gear shaft 11. It is compactly arranged between the clutch 5 and the driven transmission gear n on the counter gear shaft 12 (see FIG. 2).

The shift guide groove G of the shift drum 67 is formed so as to form a spiral over two or more rounds on the outer peripheral surface of the drum, and each speed change from the first speed to the sixth speed at every predetermined rotation angle (for example, 150 degrees) therebetween. The step positions are formed in order.
There is a neutral N position before the first gear.

  The rotation of the shift drum 67 is guided by the shift pin 58 having the engagement portion 58a engaged with the shift guide groove G in the guide long hole 8gl of the cylindrical guide portion 8g of the bearing cover member 8, and is translated in the axial direction. The shift rod 51 is moved in the axial direction via the shift rod operator 55, and the movement of the shift rod 51 is caused by the eight cam rods Cao, Cao, Cae, Cae of the engaging means 20 via the lost motion mechanisms 52, 53. , Cbo, Cbo, Cbe, Cbe.

The shift rod 51 to which the lost motion mechanisms 52 and 53 are assembled is inserted into the hollow of the counter gear shaft 12 and disposed on the central shaft.
The hollow cylindrical counter gear shaft 12 has an inner diameter substantially equal to the outer diameter of the spring holders 52h and 53h of the lost motion mechanisms 52 and 53, and the spring holders 52h and 53h attached to the shift rod 51 are slidably fitted. Insert.

Then, eight cam guide grooves 12g having a rectangular cross section are formed extending in the axial direction at eight radial positions on the hollow inner peripheral surface of the counter gear shaft 12 (see FIG. 10).
The eight cam rods Cao, Cao, Cae, Cae, Cbo, Cbo, Cbe, and Cbe are slidably fitted into the corresponding cam guide grooves 12g in the arrangement shown in FIG.
The same type of cam rod C is disposed at a symmetrical position with respect to the central axis.
The cam guide groove 12g, which serves as a detent for the cam member C with respect to the counter gear shaft 12, has a simple U-shaped cross section and can be easily machined.

  The cam guide groove 12g has a depth equal to the radial width of the cam rod C. Therefore, the cam surface which is the outer peripheral side surface of the cam rod C is in sliding contact with the bottom surface of the cam guide groove 12g, and the inner peripheral side surface is substantially the same as the hollow inner peripheral surface. A locking claw p which forms a surface and contacts the outer peripheral surface of the spring holders 52h and 53h and protrudes from the inner peripheral side surface grips either of the spring holders 52h and 53h from both sides.

Referring to FIG. 9, the counter gear shaft 12 having a hollow cylindrical shape is a left side whose outer diameter is reduced on both the left and right sides of the central cylindrical portion 12a on which the driven transmission gear n is pivotally supported via a bearing collar member 13. A cylindrical portion 12b and a right cylindrical portion 12c are formed.
A bearing 7R is fitted to the right cylindrical portion 12c of the counter gear shaft 12 via a washer 14R (see FIGS. 3 and 4).

  As shown in FIGS. 9 and 18, the left cylindrical portion 12b of the counter gear shaft 12 has an outermost shaft end portion that protrudes outward (left side) from the journal portion 12j to which the inner race 7Li of the bearing 7L is fitted. A male screw 12e formed at the end, a spline groove 12s formed inside the male screw 12e, and an outer peripheral groove 12f formed in the circumferential direction at the boundary between the male screw 12e of the spline groove 12s.

A plurality of oil introduction holes 12x are formed in the circumferential direction between the journal portion 12j and the spline groove 12s so as to communicate the inner hollow portion and the outer side of the counter gear shaft 12.
The left end opening of the inner hollow portion of the counter gear shaft 12 is closed by a plug member 39.
The assembly structure of the output sprocket 32 to be spline fitted into the spline groove 12s and the lubrication structure using the oil introduction hole 12x will be described later.

In the hollow of the counter gear shaft 12, the inner diameter of the small diameter inner surface where the cam guide groove 12g is formed is equal to the outer diameter of the spring holders 52h and 53h, and the inner diameters on both axial sides of the small diameter inner peripheral surface are cam guide grooves. A 12 g bottom surface and a large-diameter inner peripheral surface forming substantially the same peripheral surface are formed (see FIGS. 3 and 4).
About half of the shift rod operating element 55 is inserted inside the enlarged inner diameter part on the right side.

  As described above, when the shift rod 51, the lost motion mechanisms 52, 53 and the eight cam rods Cao, Cao, Cae, Cae, Cbo, Cbo, Cbe, Cbe are incorporated into the hollow of the counter gear shaft 12, all of them are incorporated. When the shift rod 51 is moved together in the axial direction, the reverse rotation odd-numbered cam rod Cbo and the forward rotation even-numbered cam rod Cae are interlocked in the axial direction via the coil spring 52s of the left lost motion mechanism 52. The forward rotation odd stage cam rod Cao and the reverse rotation even stage cam rod Cbe are linked in the axial direction via the coil spring 53s of the right lost motion mechanism 53.

  As shown in FIG. 9, the central cylindrical portion 12a on which the driven transmission gear n is pivotally supported via the bearing collar member 13 of the counter gear shaft 12 has a large outer diameter and is configured to be thick. A narrow circumferential groove 12cv that goes around in the circumferential direction on the outer periphery corresponds to the first, second, third, fourth, fifth, and sixth driven transmission gears n1, n2, n3, n4, n5, and n6. In addition, six axial grooves 12av are formed at equal intervals in the axial direction, and four axial grooves 12av oriented in the axial direction are formed at equal intervals in the circumferential direction.

  Further, on the outer peripheral portion of the central cylindrical portion 12a of the counter gear shaft 12, four portions defined by four axial grooves 12av are adjacent to each other in the circumferential direction. A long rectangular recess 12p that is elongated equally between the grooves 12av and 12av in the left and right direction, and a short length in which the groove width of the circumferential groove 12cv is evenly enlarged in the left and right directions in part between the adjacent axial grooves 12av and 12av. Rectangular recesses 12q are alternately formed in the axial direction.

Spring receiving portions 12d and 12d are formed in two axially elongated oval shapes in the axial direction and slightly recessed over the circumferential groove 12cv at two locations on the bottom surface of the long rectangular recess 12p.
Further, a pin hole 12h is formed in the radial direction up to the cam guide groove 12g on the circumferential groove 12cv at a thick portion between the short rectangular recess 12q and the axial groove 12av.

That is, the pin hole 12h is drilled in the radial direction of the cam guide groove 12g formed at eight locations in the circumferential direction from the hollow inner peripheral surface of the counter gear shaft 12.
Four pin holes 12h are formed on each circumferential groove 12cv.

The spring receiving portion 12d is provided with a compression spring 22 wound in an elliptical shape with its end fitted.
A pin member 23 is slidably inserted into the pin hole 12h.
The cam guide groove 12g communicating with the pin hole 12h is smaller than the outer diameter width of the pin member 23.
Therefore, the pin member 23 that advances and retreats through the pin hole 12h does not fall into the cam guide groove 12g, so that the engagement means 20 can be easily assembled to the counter gear shaft 12.

Since the cam rod C is slidably fitted in the cam guide groove 12g, the pin member 23 fitted in the pin hole 12h comes into contact with the cam surface of the corresponding cam rod C at the center end, and the cam rod C moves. When the cam groove v corresponds to the pin hole 12h, the pin member 23 falls into the cam groove v, and when the slidable contact surface other than the cam groove v corresponds, the pin member rides on the slidable contact surface and moves forward and backward by the movement of the cam rod C.
The advancement and retraction of the pin member 23 in the pin hole 12h causes the distal end portion of the pin member 23 to protrude outward from the bottom surface of the circumferential groove 12cv.

The swinging claw member R is formed in the circumferential groove 12cv that communicates between the long rectangular recess 12p and the short rectangular recess 12q formed on the outer peripheral portion of the central cylindrical portion 12a of the counter gear shaft 12 having the above-described structure. Is embedded, and a support pin 26 is embedded in the axial groove 12av to pivotally support the swing claw member R.
FIG. 12 shows a state where all the swinging claw members R are assembled in this way.

  In the exploded perspective view of FIG. 11, it is embedded in the circumferential groove 12cv, the long rectangular recess 12p, and the short rectangular recess 12q corresponding to the odd-stage gears (first, third, and fifth driven transmission gears n1, n3, and n5). Four oscillating claw members R, and circumferential grooves 12cv and long rectangular recesses 12p corresponding to even-numbered even gears (second, fourth and sixth driven transmission gears n2, n4, n6), The four swinging claw members R embedded in the short rectangular recess 12q are illustrated in a posture maintaining the relative angular positional relationship with each other, and in addition, a support pin that pivotally supports each swinging claw member R. 26 and a compression spring 22 and a pin member 23 acting on each swing claw member R are shown.

  The swinging claw members R are all of the same shape, have a substantially arc shape when viewed in the axial direction, and the outer peripheral portion of the through hole through which the support shaft pin 26 penetrates in the center lacks the bearing recess Rd. A wide rectangular engagement claw Rp is formed on one side of the bearing recess Rd so as to be swingably fitted to the long rectangular recess 12p. A pin hole is formed on the other side. A narrow pin receiving portion Rr that slidably fits in the circumferential groove 12cv formed with 12h extends, and an end of the pin receiving portion Rr reaches a short rectangular recess 12q to form a wide end Rq that is widened. Yes.

In the swing claw member R, the pin receiving portion Rr is fitted in the circumferential groove 12cv in which the pin hole 12h is formed, and one engaging claw portion Rp is fitted in the long rectangular recess 12p and the bearing recess Rd is formed. The other wide end Rq is fitted in the short rectangular recess 12q, matching the axial groove 12av.
Then, the support pin 26 is fitted into the matched bearing recess Rd and the axial groove 12av.

  The swinging claw member R is formed symmetrically with respect to the circumferential groove 12cv to be fitted, and one wide rectangular engagement claw Rp is heavier than the other pin receiving part Rr and the wide end Rq, When the pin 26 is pivotally supported and rotates together with the counter gear shaft 12, the swinging claw member R swings so that the engaging claw Rp acts as a weight against the centrifugal force and protrudes in the centrifugal direction.

The swinging claw member R is formed such that the pin receiving portion Rr is narrower than the engaging claw Rp side on the opposite side with respect to the swinging center.
Further, since the pin receiving portion Rr only needs to have a width sufficient to receive the pin member 23, the swinging claw member R can be formed in a small size, and the other engaging claw portion Rp can be swung by the centrifugal force. The movement can be facilitated.

  Since the swinging claw members R adjacent to each other in the circumferential direction are assembled to the counter gear shaft 12 in a symmetrical attitude, the engaging claw portions Rp, Rp facing each other with a predetermined interval are the same long rectangular recess 12p. The other wide end Rq adjacent to each other is fitted into a common short rectangular recess 12q.

  A compression spring 22 supported at one end by a spring receiving portion 12d of the counter gear shaft 12 is interposed inside the engaging claw portion Rp of the swing claw member R, and is inserted into the pin hole 12h inside the pin receiving portion Rr. The pin member 23 is interposed between the cam rod C and the pin member 23.

  In this way, the swing claw member R is pivotally supported by the support pin 26 and is embedded in the long rectangular recess 12p, the short rectangular recess 12q, and the circumferential groove 12cv of the counter gear shaft 12, The engaging claw portion Rp is urged outward by the compression spring 22, and the other pin receiving portion Rr is pressed by the advancement and retraction of the pin member 23, so that the oscillating claw member resists the urging force of the compression spring 22. R swings.

When the pin member 23 advances in the centrifugal direction and swings the swinging claw member R, the swinging claw member R has the engagement claw portion Rp submerged in the long rectangular recess 12p and the central cylinder of the counter gear shaft 12 There is nothing that protrudes outward from the outer peripheral surface of the portion 12a.
When the pin member 23 is retracted, the engaging claw Rp biased by the compression spring 22 protrudes outward from the outer peripheral surface of the central cylindrical portion 12a of the counter gear shaft 12, and can be engaged with the driven transmission gear n. To do.

  Four swinging claw members R corresponding to odd-numbered gears (first, third, and fifth driven transmission gears n1, n3, and n5) and even-numbered gears (second, fourth, and sixth driven gears) The four swinging claw members R corresponding to the transmission gears n2, n4, n6) are in a relative angular position relationship rotated 90 degrees around the axis.

  Four swinging claw members R corresponding to the odd-numbered gears (first, third, and fifth driven transmission gears n1, n3, and n5) are in contact with each other in the forward rotation direction of the gear, and each odd-stage driven transmission gear n1. , N3, n5 and the counter gear shaft 12 are engaged with each other so as to rotate in synchronization with each other, and the odd-numbered driven gears n1, n3 are in contact with each other in the reverse rotation direction of the gear. , N5 and counter gear shaft 12 are provided with a pair of counter-rotating odd-numbered engaging members Rbo that are engaged so as to rotate in synchronization with each other at symmetrical positions.

  Similarly, the four swinging claw members R corresponding to the even-numbered gears (second, fourth, and sixth driven transmission gears n2, n4, and n6) are brought into contact with each other in the forward rotation direction of the gears, and each even-numbered gear is driven. A forward rotation even-numbered-stage swinging claw member Rae engaged so that the transmission gears n2, n4, n6 and the counter gear shaft 12 rotate in synchronization with each other, and the even-numbered driven gears in contact with each other in the reverse rotation direction of the gear. A pair of counter-rotating even-numbered engaging members Rbe that are engaged so that n2, n4, and n6 and the counter gear shaft 12 rotate synchronously are provided in pairs at symmetrical positions.

The forward rotation odd-stage swinging claw member Rao is swung by the pin member 23 that moves forward and backward by the movement of the forward-rotation odd-stage cam rod Cao, and the reverse-rotation odd-stage engagement member Rbo is moved by the reverse-rotation odd-stage cam rod Cbo. It swings by the pin member 23 that advances and retreats by
Similarly, the forward rotating even-stage swinging claw member Rae is swung by the pin member 23 that moves forward and backward by the movement of the forward-rotating even-numbered cam rod Cae, and the reverse-rotating even-numbered engaging member Rbe is the reverse-rotating even-numbered cam rod. The pin member 23 is moved back and forth by the movement of Cbe to swing.

  When the engagement means 20 is incorporated in the counter gear shaft 12, first, the right end bearing collar member 13 is externally mounted on the outer peripheral end of the central cylindrical portion 12a, and the support pin 26 is inserted into the axial groove 12av inside the bearing collar member 13. The right end engaging means 20 is incorporated so that one end of the shaft is inserted, the next bearing collar member 13 is covered so as to cover the other end of the support shaft pin 26, and the driven transmission gear n is incorporated. In the same manner, the incorporation of the next-stage engaging means 20 is sequentially repeated, and finally the leftmost bearing collar member 13 is packaged to finish.

As shown in FIG. 13, the bearing collar member 13 is packaged in an axial position other than the long rectangular recess 12p and the short rectangular recess 12q of the central cylindrical portion 12a, and is continuously embedded in a line in the axial groove 12av. The support pin 26 is disposed across the adjacent support pins 26 and 26 to prevent the support pin 26 and the swinging claw member R from falling off.
Since the support pin 26 embedded in the axial groove 12av of the central cylindrical portion 12a of the counter gear shaft 12 is embedded at a depth in contact with the outer peripheral surface of the central cylindrical portion 12a, when the bearing collar member 13 is sheathed. It is fixed without play.

Seven bearing collar members 13 are mounted on the counter gear shaft 12 at equal intervals, and the driven transmission gear n is rotatably supported so as to straddle between the adjacent bearing collar members 13 and 13.
Each driven transmission gear n has a notch formed in the left and right inner periphery (the left and right periphery of the inner peripheral surface), and a thin annular protrusion 30 is formed between the left and right notches. The left and right bearing collar members 13 and 13 are slidably engaged with the notches so as to be sandwiched (see FIGS. 3 and 4).

On the protrusion 30 on the inner peripheral surface of each driven transmission gear n, six engagement convex portions 31 are formed at equal intervals in the circumferential direction (see FIGS. 3, 4, 5, and 6).
The engaging convex portion 31 has a thin arc shape when viewed from the side (the axial direction shown in FIGS. 5 and 6), and both end surfaces in the circumferential direction engage with the engaging claw portion Rp of the swing claw member R. An engagement surface is formed.

  The forward rotation odd-numbered swinging claw member Rao (forward rotation even-numbered swinging claw member Rae) and the reverse rotation odd-numbered step engagement member Rbo (reverse rotation even-numbered step engagement member Rbe) Rp and Rp are extended, and the positive rotation odd-numbered swinging claw member Rao (positive rotation even-numbered swinging claw member Rae) is an engagement convex portion in the positive rotation direction of the driven transmission gear n (and the counter gear shaft 12). The reverse rotation odd-numbered engagement member Rbo (reverse rotation even-numbered engagement member Rbe) contacts and engages the engagement convex portion 31 in the reverse rotation direction of the driven transmission gear n. To do.

  It should be noted that the forward rotation odd-numbered swinging claw member Rao (forward rotation even-numbered swinging claw member Rae) is not engaged in the reverse rotation direction of the driven transmission gear n even if the engagement claw portion Rp protrudes to the outside. In addition, the reverse rotation odd-numbered engagement member Rbo (reverse rotation even-numbered engagement member Rbe) is not engaged in the forward rotation direction of the driven transmission gear n even if the engagement claw Rp protrudes outward.

With the six driven transmission gears n thus assembled to the counter gear shaft 12, the counter gear shaft 12 is rotatably supported on the side wall of the engine case 1 and the bearing lid member 8 via the left and right bearings 7L and 7R. As a result, the six driven transmission gears n and the seven bearing collar members 13 are alternately combined and sandwiched from the left and right to perform axial positioning.
The bearing collar member 13 supports the axial force of each driven transmission gear n and can receive axial positioning and thrust force.

  When the cam rod C is in the neutral position, all the driven transmission gears n have the pin members 23 protruding from the movement positions of the cam rods C of the corresponding engaging means 20 so that the pin receiving portions Rr of the swinging claw member R are moved from the inside. In the disengaged state in which the push-up engagement claw Rp is retracted inward, it rotates freely with respect to the counter gear shaft 12.

  On the other hand, the pin member 23 enters the cam groove v by the movement position of the engagement means 20 other than the neutral position of the cam rod C, the swing claw member R swings, and the engagement claw portion Rp protrudes outward. Then, the engagement convex portion 31 of the corresponding driven transmission gear n comes into contact with the engagement claw portion Rp, and the rotation of the driven transmission gear n is transmitted to the counter gear shaft 12, or the counter gear shaft 12 Is transmitted to the driven transmission gear n.

  In the shift drive mechanism 50, the shift drum 67 is rotated by a predetermined amount by driving a shift actuator or a manual shift operation, and the shift rod 67 is rotated via a shift pin 58 fitted in the shift guide groove G. 51 is moved in the axial direction by a predetermined amount, and the eight cam rods Cao, Cao, Cae, Cae, Cbo, Cbo, Cbe, Cbe of the engaging means 20 are interlocked via the lost motion mechanisms 52, 53.

  As the cam rod C moves in the axial direction, the pin member 23 slidably in contact with the cam surface of the cam rod C moves into and out of the cam groove v to move forward and backward, swinging the swinging claw member R, and driven gear The shift is performed by releasing the engagement with n and changing the driven transmission gear n that engages with the counter gear shaft 12 by engaging with another driven transmission gear n.

  The power of the internal combustion engine is transmitted to the main gear shaft 11 through the friction clutch 5, and the first, second, third, fourth, fifth and sixth drive transmission gears m1, m2, m3, m4, m5 , M6 are integrally rotated, and the first, second, third, fourth, fifth, and sixth driven transmission gears n1, n2, n3, n4, n5, and n6, which are always meshed with them, are respectively connected. It is rotating at the rotation speed.

  3 to 6 show the first speed state. In FIG. 5, the first driven transmission gear n1 rotates in the direction of the arrow, and in FIG. 6, the second driven transmission gear n2 rotates in the direction of the arrow. The second driven transmission gear n2 rotates at a higher speed than the first driven transmission gear n1.

  Only the pin member 23 of the engaging means 20 corresponding to the first driven transmission gear n1 is in the cam groove v1 of the positive rotation odd-numbered cam rod Cao (see FIG. 3). The step swing claw member Rao protrudes outward from the engagement claw portion Rp, and the engagement convex portion 31 of the rotating first driven transmission gear n1 is engaged with the engagement claw portion Rp of the positive rotation odd step swing claw member Rao. In combination (see FIG. 5), the counter gear shaft 12 is rotated together with the first driven transmission gear n1 at the same rotational speed as the first driven transmission gear n1.

In this first speed state, in the second driven transmission gear n2, the pin member 23 of the corresponding engaging means 20 protrudes from the cam groove v2 of the even-numbered cam rods Cae and Cbe (see FIG. 4), and the engaging means Since the 20 even-stage swinging claw members Rae and Rbe have retracted the engaging claw Rp inside, they are idle.
The other third, fourth, fifth, and sixth driven transmission gears n3, n4, n5, and n6 are similarly idle (see FIGS. 3 and 4).

  Here, when there is a manual operation of the shift select lever to shift to the second speed and the shift drum 67 rotates and the shift rod 51 starts moving rightward in the axial direction, the coil springs 52s of the lost motion mechanisms 52, 53 are moved. , 53s, the eight cam rods Cao, Cao, Cae, Cae, Cbo, Cbo, Cbe, and Cbe are interlocked to move to the right in the axial direction.

Hereinafter, one state in the process of shifting up from the first speed state to the second speed state in which the reduction ratio is one step smaller at the time of acceleration by driving the internal combustion engine will be described with reference to FIG.
14A is a cross-sectional view in which the gears and the like in FIG. 3 in the state are omitted, FIG. 14B is a cross-sectional view in which the gears and the like in FIG. 4 in the state are omitted, and FIG. 14 (a) and 14 (b) are cross-sectional views taken along line cc (cross-sectional view of the first driven transmission gear n1), and FIG. 14 (d) is a cross-sectional view taken along line d- in FIGS. 14 (a) and 14 (b). FIG. 6 is a cross-sectional view taken along line d (a cross-sectional view of the second driven transmission gear n2).

  Referring to FIG. 14D, the movement of the positive rotation even-numbered cam rod Cae causes the pin member 23 to enter the cam groove v2, so that the positive rotation even-numbered swinging claw member Rae corresponding to the second driven transmission gear n2. Oscillates by the urging force of the compression spring 22 and the centrifugal force of the engaging claw Rp to project the engaging claw Rp outward, and can be engaged with the second driven transmission gear n2, together with the first driven transmission gear n1. The engaging convex portion 31 of the second driven transmission gear n2 that rotates at a higher speed than the rotating counter gear shaft 12 catches up and abuts on the engaging claw portion Rp that protrudes outside the forward rotation even-stage swinging claw member Rae.

FIG. 14 shows a state immediately before the engagement convex portion 31 of the second driven transmission gear n2 catches up with the engagement claw portion Rp protruding outside the forward rotation even-numbered swing claw member Rae. ), The engagement convex portion 31 of the first driven transmission gear n1 is engaged with the positive rotation odd-numbered swinging claw member Rao, and at the same time, the second driven transmission gear n2 is engaged as shown in FIG. Immediately before the convex portion 31 catches up with the engaging claw portion Rp projecting outside the forward rotation even-stage swinging claw member Rae.
In FIG. 14C, a lattice hatch is applied to the swinging claw member R and the engaging convex portion 31 which are effectively transmitting power.

  From the state shown in FIG. 14, when the engaging convex portion 31 of the second driven transmission gear n2 catches up with the engaging claw portion Rp protruding outside the forward rotation even-stage swing claw member Rae, the second rotating at a higher speed. The counter gear shaft 12 starts to rotate at the same rotational speed as that of the second driven transmission gear n2 by the driven transmission gear n2, and the engagement protrusion 31 of the first driven transmission gear n1 engages the positive rotation odd-numbered swing claw member Rao. The nail | claw part Rp leaves | separates and the upshift from actual 1st speed to 2nd speed is performed.

  When the engagement claw Rp of the positive rotation odd-numbered swinging claw member Rao is separated from the engagement convex portion 31 of the first driven transmission gear n1, the frictional resistance for fixing the positive rotation odd-numbered swinging claw member Rao is eliminated. The positive rotation odd-numbered cam rod Cao urged by the coil spring 53s of the lost motion mechanism 53 moves backward and the pin member 23 that has entered the cam groove v1 comes out and swings in the positive rotation odd-numbered step. The claw member Rao is swung and the engagement claw portion Rp is retracted inward.

  As described above, when shifting up from the first-speed acceleration state to the second-speed state in which the reduction ratio is one step smaller, the engagement convex portion 31 of the first driven transmission gear n1 is moved in the positive rotation odd-numbered swing claw member Rao. The engaging convex portion of the second driven transmission gear n2 that rotates at a higher speed while the counter gear shaft 12 rotates at the same speed as the first driven transmission gear n1 by contacting and engaging with the engaging claw Rp. Since the counter 31 catches up with the engagement claw Rp of the forward rotation even-numbered swing claw member Rae and rotates the counter gear shaft 12 at a higher speed together with the second driven transmission gear n2, the first driven transmission gear is shifted. Since the engaging claw Rp of the positive rotation odd-numbered swinging claw member Rao is separated from the engaging convex portion 31 of n1 naturally and the engagement is smoothly released, a force is not required for releasing the engagement smoothly. Operates and can perform smooth upshifts.

  Similarly, each shift-up from 2nd to 3rd, 3rd to 4th, 4th to 5th, and 5th to 6th is performed with the driven transmission gear n engaged with the swinging claw member R. Since the driven transmission gear n with a reduction ratio of one step is engaged with the swinging claw member R and shifted up, no force is required to release the engagement and the clutch is not required for shifting. In addition, there is no loss in the switching time at the time of upshifting, there is no loss of driving force, and the shift shock is small, so that smooth upshifting can be performed.

Similarly, in the downshift, the driven claw member R is engaged with the driven transmission gear n whose gear ratio is one step larger while the driven transmission gear n is engaged with the swing claw member R, and the downshift is performed. Therefore, no force is required for disengagement, it operates smoothly and does not require a clutch for shifting, there is no loss in switching time at the time of downshifting, there is no loss of driving force, and the shift shock is small Smooth downshifting can be done.

The counter gear shaft 12 accommodates a shift rod 51, eight cam rods C, lost motion mechanisms 52, 53, etc. in the inner hollow portion, and it is necessary to supply lubricating oil to these sliding members. As shown in FIG. 6, since the output sprocket 32 is provided at the left end portion of the counter gear shaft 12, and a part of the speed change drive mechanism 50 is provided at the right end portion, the lubricating oil cannot be introduced from both ends.
Therefore, the counter gear shaft 12 employs a lubrication structure in which an oil introduction hole 12x is formed on the left side of the shaft support portion by the left bearing 7L to introduce lubricant from the outer peripheral surface.

Hereinafter, a lubricating structure for supplying lubricating oil to the inner hollow portion of the counter gear shaft 12 will be described with reference to FIGS.
Referring to the top view and the side view of the lower engine case 1L of FIGS. 15 and 16, the bearing portion 1b that fits and supports the outer race 7Lo of the bearing 7L of the lower engine case 1L has a reduced inner diameter. A bearing opening 1e bulging outward in the direction is provided, and inner circumferential grooves 1bv and 1ev are formed on the outer sides in the axial direction of the inner circumferential surfaces of the bearing 1b and the bearing opening 1e.
Moreover, the inner peripheral protrusion 1ep is formed in the axial direction inner side of the inner peripheral surface of the bearing opening 1e (see FIG. 18).

The bearing 1b and the bearing opening 1e are also formed in the upper engine case 1R.
As shown in FIGS. 15 and 16, a main oil passage Y is formed in the lower engine case 1L, and a branch oil passage y branched from the main oil passage Y extends to the bearing opening 1e so as to extend to the bearing opening 1e. An oil passage opening 1x is formed on the inner peripheral surface (see FIG. 18).

  On the other hand, the counter gear shaft 12 is in a state in which the bearing 7L is fitted to the journal portion 12j with the washer 14L interposed between the journal portion 12j and the central cylindrical portion 12a having the maximum outer diameter (see FIG. 17). When the outer race 7Lo is positioned and fitted to the bearing portion 1b with the retaining ring 45, an annular space is formed between the inner peripheral surface of the bearing opening 1e and the outer peripheral surface of the counter gear shaft 12, as shown in FIG. The oil passage opening 1x of the branch oil passage y of the lower engine case 1L and the oil introduction hole 12x of the counter gear shaft 12 open to the annular space at substantially the same axial position.

An annular oil seal 40 is fitted into the inner peripheral surface of the bearing opening 1e having the oil passage opening 1x, and the inner peripheral surface of the oil seal 40 and the outer peripheral surface of the counter gear shaft 12 having the oil introduction hole 12x. A cylindrical collar member 33 is inserted between them.
As shown in FIG. 19, the annular oil seal 40 includes a large-diameter outer annular seal portion 41 in which a rubber member is baked on an annular metal piece bent in an L-shaped cross section between a cylindrical portion and an inner flange portion. The inner annular seal piece 42 is coaxially configured with the inner flange portions facing each other and offset from each other in the axial direction, and rubber members are connected to each other.

The outer annular seal piece 41 is positioned on the outer side in the axial direction of the counter gear shaft 12, and the inner annular seal piece 42 on the inner side in the axial direction has an appropriate space inside the cylindrical portion of the outer annular seal piece 41. It has entered.
The rubber member of the outer annular seal piece 41 is formed such that the inner peripheral edge portion of the inner flange portion is formed with an annular elastic lip portion 41i extending obliquely slightly toward the center axis toward the inner side in the axial direction, The cylindrical portion of the piece 42 is configured to be inserted between the cylindrical portion of the outer annular seal piece 41 and the annular elastic lip portion 41i.
A ring spring 43 is fitted around the tip of the annular elastic lip 41i.

On the other hand, the inner annular seal piece 42 is obliquely outward (in the axial direction of the counter gear shaft 12) from the inner peripheral edge (the inner peripheral edge of the oil seal 40 in the axial direction) toward the central axis. The inner elastic lip portion 42i protruding toward the left side in FIG. 7 is provided in an annular shape.
Further, an outer elastic lip portion 42o protruding inward in the oblique axial direction from the outer peripheral edge portion of the inner flange portion of the inner annular seal portion piece 42 to the distal side is provided in an annular shape.
Therefore, the oil seal 40 is formed with an inner circumferential annular opening 40xi opened in the circumferential direction between the annular elastic lip portion 41i and the inner elastic lip portion 42i on the inner circumferential surface, and the outer annular sealing piece on the outer circumferential surface. An outer peripheral annular opening 40xo opened in the circumferential direction is formed between the cylindrical portion 41 and the outer elastic lip portion 42o.

  The outer annular seal portion piece 41 and the inner annular seal portion piece 42 are formed in an inner annular seal portion in a U-shaped cross section composed of a cylindrical portion, an inner flange portion, and an annular elastic lip portion 41i of the outer annular seal portion piece 41. A rubber member is partially connected to a gap having a U-shaped cross section formed between the cylindrical portions of the pieces 42, leaving the internal communication path 40x, and the internal communication path 40x is connected to the outer annular opening 40xo. The inner annular opening 40xi is communicated.

The maximum outer diameter of the oil seal 40 is an outer diameter formed by the outer peripheral surface of the rubber member of the cylindrical portion of the outer annular seal piece 41, which is somewhat larger than the inner diameter of the bearing opening 1e, but changes elastically.
The minimum inner diameter when the external force of the oil seal 40 is not applied is the inner diameter ds formed by the annular elastic lip 41i and the inner elastic lip 42i (see FIG. 19).
Note that the inner diameter of the oil seal 40 changes elastically.

On the other hand, the cylindrical collar member 33 inserted between the inner peripheral surface of the oil seal 40 and the outer peripheral surface of the counter gear shaft 12 is a main portion 33a excluding the axially inner end portion 33e with reference to FIG. The outer diameter d2 of the axially inner end 33e is smaller than the outer diameter (maximum outer diameter of the cylindrical collar member 33) d1.
The tip end of the axially inner end portion 33e is tapered to form a tapered surface 33t, and the outer diameter d3 of the tip edge of the tapered surface 33t is smaller than the inner diameter ds of the inner elastic lip portion 42i. The outer diameter d2 of the inner end 33e is larger than the inner diameter ds of the inner elastic lip 42i.
That is, d3 <ds <d2 <d1.

On the inner circumferential surface of the cylindrical collar member 33, an inner circumferential groove 33xi is formed over the circumference of the boundary between the main portion 33a and the axially inner end portion 33e, and from the inner circumferential groove 33xi to the outer circumferential surface. A plurality of communication holes 33x to be drilled are formed in the circumferential direction.
The cylindrical collar member 33 has a notch 33b formed on the outer peripheral edge of the outer end in the axial direction.

As shown in FIG. 20, an oil seal 40 is inserted into the bearing opening 1e of the engine case 1, is fitted into a predetermined position on the inner circumferential surface of the bearing opening 1e, and is fitted to the inner circumferential groove 1ev. When positioned by 46, the outer elastic lip portion 42o comes into pressure contact with the inner peripheral protrusion 1ep, and the outer peripheral annular opening 40xo faces the oil passage opening 1x on the inner peripheral surface of the bearing opening 1e.
Thus, the cylindrical collar member 33 is inserted between the inner peripheral surface of the oil seal 40 and the outer peripheral surface of the counter gear shaft 12 that are fitted in the bearing opening 1e.

  The cylindrical collar member 33 is inserted into the oil seal 40 having an inner diameter ds smaller than the outer diameter d2 from the axially inner end 33e side (tapered surface 33t side) of the outer diameter d2 having a smaller outer diameter than the main body portion 33a. The tapered surface 33t at the tip of the axially inner end portion 33e is first in contact with the annular elastic lip portion 41i to expand the diameter, and then the inclined tapered surface 33t at the tip of the axially inner end portion 33e is inclined toward the central axis side. The tip end edge of the inner elastic lip portion 42i projecting outward in the axial direction is in contact with the tip end of the inner elastic lip portion 42i from the outer side in the axial direction. The inner elastic lip portion 42i is in a normal posture in which the inner elastic lip portion 42i faces the outer side in the oblique axial direction toward the central axis as shown by the solid line in FIG. The outer periphery of the axially inner end 33e of the cylindrical collar member 33 Elastically pressed against the.

  Since the cylindrical collar member 33 has a smaller outer diameter d2 at the axially inner end 33e than the main body 33a and has a tapered surface 33t at the tip, the inner elastic lip 42i is turned over by the insertion of the cylindrical collar member 33. Therefore, the inner elastic lip portion 42i is moved to the central axis side diagonally in the axial direction by one insertion operation without returning to the original normal posture by repeatedly moving back and forth. The cylindrical collar member 33 can be pressed into contact with the normal posture.

When the cylindrical collar member 33 inserted as described above comes into contact with the inner race 7Li of the bearing 7L, the communication hole 33x of the cylindrical collar member 33 faces the inner peripheral annular opening 40xi of the oil seal 40, and the cylindrical collar The oil introduction hole 12x of the counter gear shaft 12 faces the inner circumferential groove 33xi of the member 33 (see FIG. 20).
In this way, the present lubrication structure that supplies the inner hollow portion of the counter gear shaft 12 is configured.

  That is, in the present lubricating structure, as shown by an arrow in FIG. 20, the oil branched into the branch oil passage y branched from the main oil passage Y of the lower engine case 1L is opened on the inner peripheral surface of the bearing opening 1e. It flows into the outer peripheral annular opening 40xo of the oil seal 40 from the oil passage opening 1x, passes through the internal communication passage 40x in the oil seal 40, enters the communication hole 33x of the cylindrical collar member 33 from the inner peripheral annular opening 40xi, and has an inner peripheral groove. The oil is introduced into the oil introduction hole 12x of the counter gear shaft 12 through 33xi and supplied to the inner hollow portion of the counter gear shaft 12 through the oil introduction hole 12x.

  As shown by a solid line in FIG. 21 in which the main portion is enlarged, the inner elastic lip 42i of the oil seal 40 is elastically pressed against the cylindrical collar member 33 in a posture facing the outer side in the oblique axial direction toward the central axis. The hydraulic pressure of the oil flowing through the internal communication passage 40x of the oil seal 40 further acts in the direction in which the inner elastic lip 42i is elastically pressed against the cylindrical collar member 33, as shown by the arrows in FIG. Thus, the gap between the cylindrical collar member 33 and the outer peripheral surface of the cylindrical collar member 33 can be reliably closed to prevent oil leakage, and sufficient oil can be supplied to the inner hollow portion of the counter gear shaft 12.

If the cylindrical collar member 33 does not have the tapered surface 33t at the tip of the axial inner end 33e, the cylindrical collar member 33 is perpendicular to the insertion direction of the axial inner end 33e when the cylindrical collar member 33 is inserted. The tip end surface may come into contact with the tip edge of the inner elastic lip 42i of the oil seal 40, and the tip edge may be turned over. Although the outer diameter d2 of the inner end 33e in the axial direction is relatively small, the end of the inner elastic lip 42i turned over by its own elastic force when the insertion is finished. It is possible to return to a normal posture directed outward in the oblique axis direction toward the central axis side.
As described above, the inner elastic lip 42i can be returned to the original normal posture. However, the insertion of the cylindrical collar member 33 is not smooth due to the turned-up inner elastic lip 42i.

Further, if the outer diameter d2 of the axially inner end portion 33e is not reduced but has the same outer diameter d1 as that of the main portion 33a, as shown by a two-dot chain line in FIG. The inner elastic lip portion 42i turned over largely by the outer peripheral surface of the relatively large outer diameter d1 of 33e cannot return to a normal posture directed outward in the oblique axial direction toward the central axis due to its own elastic force. is there.
When the inner elastic lip portion 42i is turned over in this way, the oil pressure of the oil flowing through the internal communication passage 40x of the oil seal 40 acts in a direction to further turn the inner elastic lip portion 42i, and the cylindrical collar member 33 There is a possibility that the lubricating oil leaks by forming a gap with the outer peripheral surface of the motor, and the lubricating oil is not sufficiently supplied to the inner hollow portion of the counter gear shaft 12.

  Therefore, the cylindrical collar member 33 has an outer diameter d2 of the axially inner end portion 33e smaller than that of the main portion 33a, thereby preventing the inner elastic lip portion 42i from turning over and preventing leakage of lubricating oil. By having the tapered surface 33t at the distal end of the cylindrical collar member 33, the cylindrical collar member 33 can be smoothly inserted and assembled.

As described above, the oil seal 40 is fitted into the bearing opening 1 e of the engine case 1, and the cylindrical collar member 33 is fitted between the inner circumferential surface of the oil seal 40 and the outer circumferential surface of the counter gear shaft 12. After that, the disc spring 34 is engaged with the notch 33b of the cylindrical collar member 33, and the output sprocket 32 is spline fitted into the sprocket groove 12s of the counter gear shaft 12.
That is, the counter gear shaft 12 is an output shaft, and a chain 38 is wound around an output sprocket 32 fitted with a spline, and power is transmitted to the rear wheel side via the chain 38, so that the vehicle travels.

  On the counter gear shaft 12, a pair of half cotters 35, 35 are fitted to the outer circumferential groove 12f so that the output sprocket 32 fitted to the sprocket groove 12s on the spline groove 12s is pressed from the left side. An annular retainer 36 is fitted on the cotters 35, 35.

The annular retainer 36 includes an outer peripheral surface and an outer peripheral wall facing the outer peripheral surface and outer surface of the half cotters 35 and 35 that are combined in an annular shape. When the annular side wall abuts on the outer surface of the half cotters 35 and 35, The wall covers the outer peripheral surface of the half cotters 35 and 35 and holds the half cotters 35 and 35.
Then, a bag-like nut member 37 is screwed into the outermost male screw 12e of the counter gear shaft 12, and the annular retainer 36 is sandwiched between the half cotter 35 and fixed (see FIG. 17).

Thus, the output sprocket 32 that is spline-fitted to the counter gear shaft 12 is in contact with the half cotter 35 and is restricted from moving in the axial direction, and is connected to the cylindrical collar member 33 that is in contact with the inner race 7Li of the bearing 7L. It is elastically pressed against the half cotter 35 by a disc spring 34 interposed therebetween.
Therefore, stable power transmission is possible by always positioning the output sprocket 32 within the required axial range while absorbing the force component acting in the axial direction acting on the output sprocket 32 when the chain 38 is wound by the disc spring 34. It is said.

Here, the lubricating structure of the counter gear shaft 12 of the multi-stage transmission 10 will be described.
As shown in the left side view of the counter gear shaft 12 in FIG. 10, the radial inner surface of the counter gear shaft 12 has four radial positions where the eight cam guide grooves 12g are arranged every other two. The axial direction oil supply groove 12y is cut in parallel with the cam guide groove 12g (see FIG. 5 and FIG. 6).

Each of the axial oil supply grooves 12y communicates with a radial oil supply hole 12z that is drilled in the radial direction at an axial position where the required pin member 23 exists, and the radial oil supply hole 12z is connected to the axial oil supply groove 12y and the swinging claw member. It communicates with the circumferential groove 12cv in which R is fitted.
In addition, each axial direction oil supply groove | channel 12y does not connect to the radial direction oil supply hole 12z drilled by the adjacent axial direction position among the axial direction positions in which the pin member 23 is located, but the radial direction of every other axial position It communicates with the oil supply hole 12z.

  That is, of the four axial oil supply grooves 12y, the two opposing axial oil supply grooves 12y correspond to odd-numbered gears (first, third, and fifth driven transmission gears n1, n3, and n5). It communicates with the radial oil supply hole 12z that opens in the circumferential groove 12cv where the pin member 23 is located (see FIG. 11), and the other two opposite axial oil supply grooves 12y are even gears (second and fourth gears). , The sixth driven transmission gear n2, n4, n6) communicates with the radial oil supply hole 12z opened in the circumferential groove 12cv where the pin member 23 is located (see FIG. 12).

  The lubricating oil introduced into the hollow end portion of the counter gear shaft 12 by the oil introduction hole 12x is guided in the axial direction along the inner peripheral surface of the hollow portion of the counter gear shaft 12 by the axial oil supply groove 12y. Even with a small oil supply actuator, the oil switching resistance (swinging claw member R, pin member 23, engagement means 20 such as compression spring 22 and cam rod C) is smoothly lubricated and sufficiently supplied with oil. Can be lubricated.

  Four axial oil supply grooves 12y are formed, and each axial oil supply groove 12y does not communicate with the radial oil supply holes 12z drilled at the adjacent axial position among the axial positions where the pin member 23 is located. Lubricating oil supplied from one end of the axial oil supply groove 12y can be passed to the other end without much lowering the hydraulic pressure, and can be supplied substantially evenly to the engagement switching mechanisms arranged in the axial direction.

E ... Internal combustion engine, 1 ... Engine case, 1U ... Upper engine case, 1L ... Lower engine case, 1b ... Bearing portion, 1e ... Bearing opening, Y ... Main oil passage, y ... Branch oil passage, 2 ... Shift chamber DESCRIPTION OF SYMBOLS 4 ... Primary driven gear, 5 ... Friction clutch, 6 ... Crankshaft, 7L, 7R ... Bearing, 8 ... Bearing cover member, 10 ... Multi-stage transmission, 11 ... Main gear shaft, 12 ... Counter gear shaft, 12x ... Oil Introduction hole, 12y ... Axial lubrication groove, 12z ... Diameter lubrication hole, 12j ... Journal part, 12s ... Spline groove, 12e ... Male thread, 12f ... Outer circumferential groove, 13 ... Bearing collar member,
20 ... engaging means, 32 ... output sprocket, 33 ... cylindrical collar member, 33e ... axial end, 33t ... tapered surface, 33x ... communication hole, 34 ... disc spring, 35 ... half-cotter, 36 ... annular Retainer, 37 ... Nut member,
40 ... Oil seal, 40x ... Internal communication passage, 40xi ... Inner ring opening, 40xo ... Outer ring opening, 41 ... Outer ring seal piece, 41i ... Ring elastic lip, 42 ... Inner ring seal piece, 42i ... Inside Elastic lip, 42o ... Outer elastic lip, 43 ... Ring spring,
50 ... shift drive mechanism, 51 ... shift rod, 55 ... shift rod operator, 58 ... shift pin, 67 ... shift drum,
m: drive transmission gear, n: driven transmission gear, C: cam rod, R: swing claw member.

Claims (5)

An annular oil seal (40) is fitted inside the inner peripheral surface of the bearing opening (1e) of the case (1) that rotatably supports the shaft member (12),
A cylindrical collar member (33) is inserted between the inner peripheral surface of the oil seal (40) and the outer peripheral surface of the shaft member (12),
The cylindrical collar member (33) is provided with a communication hole (33x) communicating from the outer peripheral surface to the inner peripheral surface,
The shaft member (12) has an oil introduction hole (12x) communicating with the hollow portion inside the shaft member at a position facing the communication hole (33x) of the cylindrical collar member (33),
The oil seal (40) includes an outer peripheral annular opening (40xo) that opens in the circumferential direction on the outer peripheral surface and an inner peripheral annular opening (40xi) that opens in the circumferential direction on the inner peripheral surface. ) And an annular elastic lip portion (41i) which is provided obliquely inward in the axial direction from the inner peripheral edge of the axially outer side to the central axis side, and from the inner peripheral edge of the axially inner side to the central axis side An inner elastic lip portion (42i) protruding toward the outer side in the oblique axis direction is provided in an annular shape,
The outer peripheral annular opening (40xo) faces the oil passage opening (1x) on the inner peripheral surface of the bearing opening (1e),
The inner annular opening (40xi) faces the communication hole (33x) of the cylindrical collar member (33), and the inner elastic lip portion (42i) is an axially inner end of the cylindrical collar member (33). In a lubricating structure configured to guide the lubricating oil from the inner annular opening (40xi) to the communication hole (33x) by elastically pressing the outer peripheral surface of the portion (33e) ,
The minimum inner diameter when no external force is applied to the oil seal (40) is the inner diameter (ds) formed by the annular elastic lip portion (41i) and the inner elastic lip portion (42i),
The cylindrical collar member (33), the lubricating structure, wherein the outer diameter (d2) smaller of the axial inner end as compared to the maximum outer diameter (d1) (33e).   The tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the outer diameter (d3) of the tip edge of the tapered surface (33t) The lubricating structure according to claim 1, wherein is smaller than an inner diameter (ds) of the inner elastic lip portion (42i) of the oil seal (40). A plurality of drive gears (m1 to m6) and driven gears (n1 to n6) are respectively mounted on parallel gear shafts (12) that are rotatably mounted via a pair of bearings (7L, 7R) in the case (1). Is always supported in mesh with each gear stage, and a plurality of one of the drive gears (m1 to m6) and the driven gears (n1 to n6) are fixed to the gear shaft (11), and the other plurality of gears. An engagement switching mechanism that switches the engagement between the gear shaft and each gear between the gear and the gear shaft (12) for each gear is provided, and the engagement switching mechanism is driven by a shift drive mechanism to perform a shift. Machine,
The engagement switching mechanism is
Engagement portions (31) provided with engagement surfaces in the circumferential direction at a plurality of locations in the circumferential direction of the inner circumferential surface of each gear (n1 to n6);
A swinging claw member (R) that engages and disengages the engagement surface of the engagement portion (31) with one end pivotally supported by the gear shaft (12),
A pin member (23) in contact with the other end of the front swinging claw member (R) from the inside in the radial direction;
A plurality of sliding contact surfaces which are axially moved by being fitted into cam guide grooves (12g) cut in the axial direction on the inner peripheral surface of the hollow portion of the gear shaft (12) and slidably contact the pin member (23). The cam surfaces (v1 to v6) are formed at required locations in the axial direction, and include a plurality of cam rods (C) that actuate the swing claw member (R) via the pin member (23) by movement,
The speed change drive mechanism is provided with a multistage shift rod (51) that is inserted into the hollow central shaft of the gear shaft (12) inside the cam rod (C) and moves the cam rod (C) by axial movement. In the transmission,
An annular oil seal (40) is fitted in the inner peripheral surface of the bearing opening (1e) of the case (1) that rotatably supports the gear shaft (12),
A cylindrical collar member (33) is inserted between the inner peripheral surface of the oil seal (40) and the outer peripheral surface of the gear shaft (12),
The cylindrical collar member (33) is provided with a communication hole (33x) communicating from the outer peripheral surface to the inner peripheral surface,
The gear shaft (12) has an oil introduction hole (12x) communicating with the hollow portion inside the gear shaft at a position facing the communication hole (33x) of the cylindrical collar member (33),
The oil seal (40) includes an outer peripheral annular opening (40xo) that opens in the circumferential direction on the outer peripheral surface and an inner peripheral annular opening (40xi) that opens in the circumferential direction on the inner peripheral surface. ) And an annular elastic lip portion (41i) which is provided obliquely inward in the axial direction from the inner peripheral edge of the axially outer side to the central axis side, and from the inner peripheral edge of the axially inner side to the central axis side An inner elastic lip portion (42i) protruding toward the outer side in the oblique axis direction is provided in an annular shape,
The outer peripheral annular opening (40xo) faces the oil passage opening (1x) on the inner peripheral surface of the bearing opening (1e),
The inner annular opening (40xi) faces the communication hole (33x) of the cylindrical collar member (33), and the inner elastic lip portion (42i) is an axially inner end of the cylindrical collar member (33). A lubricating structure configured to guide the lubricating oil from the inner annular opening (40xi) to the communication hole (33x) by elastically pressing the outer peripheral surface of the portion (33e) ,
The minimum inner diameter when no external force is applied to the oil seal (40) is the inner diameter (ds) formed by the annular elastic lip portion (41i) and the inner elastic lip portion (42i),
The cylindrical collar member (33), the multi-speed transmission, wherein the outer diameter (d2) smaller of the axial inner end as compared to the maximum outer diameter (d1) (33e).   The tip of the axially inner end (33e) of the cylindrical collar member (33) is tapered to form a tapered surface (33t), and the tip outer diameter (d3) is the above-mentioned of the oil seal (40). 4. The multi-stage transmission according to claim 3, wherein the multi-stage transmission is smaller than an inner diameter (ds) of the inner elastic lip portion (42i). The gear shaft (12) provided with the engagement switching mechanism is an output shaft (12),
A shaft end protruding outward from the journal portion (12j) to which the inner race (7Li) of the bearing (7L) in the output shaft (12) is fitted is a male screw (12e) formed at the outermost end. A spline groove (12s) formed on the inner side of the male screw (12e) and an outer peripheral groove (12f) formed in the circumferential direction at the boundary between the male screw (12e) of the spline groove (12s). ,
The cylindrical collar member (33) externally fitted to the output shaft (12) is in contact with the inner race (7Li) fitted to the journal portion (12j),
The output sprocket (32) that is spline-fitted into the spline groove (12s) presses the cylindrical collar member (33) with a disc spring (34) interposed therebetween,
The half cotter (35) fitted in the outer circumferential groove (12f) receives the output sprocket (32),
An annular retainer (36) comprising an outer peripheral wall and an annular side wall facing the outer peripheral surface and the outer surface of the half cotter (35) is externally fitted to the half cotter (35), and the half cotter (35) is attached. Hold and
The nut member (37) screwed into the male screw (12e) is configured to sandwich the annular retainer (36) with the half cotter (35). The described multi-stage transmission.

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