JP5254286B2 - Support structure for transmission fork shaft - Google Patents

Description

  The present invention relates to a support structure for a fork shaft of a transmission for a vehicle.

  2. Description of the Related Art Conventionally, various types of vehicle manual transmissions having a plurality of shift stages for forward movement are known (see, for example, Patent Document 1). FIG. 10 shows an example of this type of typical transmission. The transmission includes an input shaft that forms a power transmission system with the output shaft of the engine and an output shaft that forms a power transmission system with the drive wheels.

  The input shaft of the transmission is provided with a plurality of shift stage drive gears coaxially and non-rotatably. The output shaft of the transmission is provided with a plurality of shift gears that are meshed with the corresponding drive gears so as to be coaxial and relatively rotatable. Hereinafter, a gear provided on the shaft so as not to be relatively rotatable is referred to as a “fixed gear”, and a gear provided on the shaft so as to be relatively rotatable is referred to as a “spinning gear”.

  A corresponding hub is fixed to a portion of the output shaft adjacent to each idler gear, and a corresponding sleeve is splined to the outer periphery of the corresponding hub so as to be movable in the axial direction. Each idle gear is fixed to the output shaft so as not to rotate relative to the output shaft by moving the corresponding sleeve in the axial direction and spline-fitting with the corresponding sleeve. When one idler gear is fixed to the output shaft so as not to rotate relative to the output shaft, a power transmission system is formed between the engine and the drive wheel via the idler gear and a fixed gear meshing with the idler gear. The That is, a gear stage corresponding to the idle gear is established in the transmission, and torque based on the engine torque is applied to the idle gear.

  In general, a corresponding fork is integrally connected to each sleeve. Each fork is integrally connected to a corresponding fork shaft. Accordingly, the axial position of each sleeve is adjusted by independently adjusting the axial position of the corresponding fork shaft. That is, in general, a plurality of fork shafts are supported so as to be independently movable in the axial direction with respect to the housing (case) of the transmission.

  In recent years, press-molded fork shafts having a rectangular cross section have been used. As a result, the manufacturing cost of the fork shaft can be reduced as compared with a conventional fork shaft having a circular cross section produced by cutting or the like, and adjacent when a plurality of fork shafts are arranged side by side in parallel. There is an advantage that the interval between fork shafts can be narrowed.

  For example, a structure shown in FIG. 11 is conceivable as a structure for supporting a fork shaft having a rectangular cross section so as to be movable in the axial direction with respect to the housing of the transmission. That is, both ends of a plurality of (three) fork shafts having a rectangular cross section are inserted into rectangular through holes formed in the pair of plates, respectively. A pair of plates are each fixed to the housing.

  However, in the structure shown in FIG. 11, when an external force (torsional moment) in the torsional direction is applied around the axis of the fork shaft for some reason, as compared with a structure in which a conventional fork shaft having a circular cross section is adopted. The sliding resistance of the sliding part between the fork shaft and the through hole increases, and the surface pressure of the sliding part increases. Hereinafter, this point will be described.

  When a torsional moment is applied around the axis of the fork shaft, the fork shaft and the fork integrated with the fork shaft rotate around the axis. Here, in a conventional structure in which a fork shaft having a circular cross section is inserted into a circular through hole, the fork shaft can freely rotate with respect to the through hole. Accordingly, as the fork integrated with the fork shaft rotates, the clearance between the engaging portion of the fork and the sleeve decreases, and the engaging portion of the fork and the sleeve comes into contact with each other. As a result, a pair of reaction forces (couples) for balancing the fork receiving the torsional moment in the rotation direction are respectively generated in the engaging portion between the fork and the sleeve and the sliding portion between the fork shaft and the through hole. Occur. Here, since the engaging portion between the fork and the sleeve is located near the tip of the fork, the span between the engaging portion between the fork and the sleeve and the sliding portion between the fork shaft and the through hole is relatively long. . Accordingly, the reaction force generated at the sliding portion between the fork shaft and the through hole is also relatively small.

  On the other hand, in a structure in which a fork shaft having a rectangular cross section is inserted into a rectangular through hole, the clearance between the fork and the sleeve in the process of rotating the fork integrated with the fork shaft is reduced. In addition to decreasing, the clearance between the “four edges of the fork shaft” and the “inner surface of the through hole” also decreases. Here, depending on the dimensional relationship related to the clearance between the two, before the engaging portion between the fork and the sleeve comes into contact, “two edges located on the diagonal line among the four edges of the fork shaft” and “the through hole” The inner surface of ". In this case, a pair of reaction forces (couples) for balancing the fork shaft that receives the torsional moment in the rotation direction are “two edges located on the diagonal line among the four edges of the fork shaft” and “through hole. Occurs at the contact portion with the "inner surface". Here, the span of “two edges located on the diagonal line in the fork shaft” is usually smaller than “the span of the engaging portion between the fork and the sleeve and the sliding portion between the fork shaft and the through hole”. .

  As described above, in the structure in which the fork shaft having a rectangular cross section is inserted into the rectangular through hole, the fork shaft is compared with the conventional structure in which the fork shaft having a circular cross section is inserted into the circular through hole. The reaction force generated at the sliding portion with the through hole can be increased. Accordingly, the sliding resistance of the sliding portion between the fork shaft and the through hole increases, and the surface pressure of the sliding portion increases. As a result, the fork shaft cannot slide smoothly with respect to the plate, which may cause a problem that the driver's shift feeling deteriorates.

  In addition, since the edge of the fork shaft locally contacts the inner surface of the through hole, the inner surface of the through hole is likely to be locally worn. In order to suppress the progress of the wear, there is a problem in that it is necessary to perform heat treatment or the like for increasing the hardness in the vicinity of the inner peripheral surface of the through hole in the plate (see the area surrounded by the oblique lines in FIG. 11). Can occur.

Japanese Patent No. 2543874

  In view of the above, the object of the present invention is to prevent the driver's shift feeling from getting worse by smoothly moving the fork shaft even if a torsional external force is applied around the fork shaft having a rectangular cross section. Another object of the present invention is to provide a support structure for a fork shaft of a transmission.

  The structure for supporting a fork shaft of a transmission according to the present invention is a structure for supporting a fork shaft having a rectangular cross section. This fork shaft moves in the axial direction in response to a shift operation from the neutral position of the shift lever of the vehicle.

  This support structure includes a pair of support members and a pair of attachment portions. A rectangular through hole is formed in each of the pair of support members. The pair of attachment portions are coaxially formed so as to face each other on the housing side of the transmission.

  The pair of support members are fixed to the pair of attachment portions, respectively. Both end portions of the fork shaft are inserted into the through holes of the pair of support members so as to be relatively movable in the axial direction. Accordingly, the fork shaft is supported so as to be movable in the axial direction with respect to the housing.

  In this support structure, all four surfaces connected through the four corners of the outer peripheral surface of the fork shaft are flat surfaces, and are connected through the four corners of the inner peripheral surface of the through hole of the support member. The four surfaces to be formed are all convex surfaces protruding inward.

  According to this, when an external force in the torsional direction is applied around the shaft of the fork shaft for some reason, “the four corners (edges) of the outer peripheral surface of the fork shaft are not contacted before the engaging portion between the fork and the sleeve comes into contact. The situation of “contacting the inner surface of the through hole” does not occur (difficult). Therefore, the above-described problem of “increase in sliding resistance of the sliding portion between the fork shaft and the through hole and increase in surface pressure of the sliding portion” due to this does not occur (is difficult). As a result, the fork shaft can slide smoothly with respect to the support member, and the shift feeling of the driver does not deteriorate (is difficult).

  Alternatively, in this support structure, among the four surfaces connected via the four corners of the outer peripheral surface of the fork shaft, the first set of two surfaces facing each other is a flat surface and the second set facing each other Each of the two surfaces is a convex surface protruding outward, and two of the four surfaces connected via the four corners of the inner peripheral surface of the through hole of the support member correspond to the first set. Each of the surfaces may be a convex surface protruding inward, and the two surfaces corresponding to the second set may be concave surfaces recessed outward.

  This also can produce the same actions and effects as described above. Furthermore, the two surfaces (convex surfaces) of the second set of fork shafts and the two surfaces (concave surfaces) of the second set of through holes of the support member are not points (relatively small areas) but surfaces (comparison). Large area). As a result, even if an external force is applied to the fork shaft in a direction that increases the contact surface pressure, the contact surface pressure is unlikely to be excessive. As a result, the driver's shift feeling does not deteriorate (is difficult).

  Specifically, for example, a case is assumed in which a shift head is attached to one of the two surfaces of the second set of fork shafts and a fork is attached to the other. In this case, when the shift head is pressed in one axial direction by the shift inner lever (see the black arrow in FIG. 3), the fork receives a reaction force in the opposite axial direction from the corresponding sleeve (in FIG. 3). See white arrow). Here, the shift head and the fork are separated. Therefore, a rotational moment is generated on the fork shaft. This rotational moment becomes an external force in the direction of increasing the contact surface pressure. However, for the reasons described above, the above-described contact surface pressure is unlikely to be excessive, so that the driver's shift feeling is unlikely to deteriorate.

It is a skeleton figure showing the principal section of the whole axial direction of the whole transmission to which the support structure of a fork shaft concerning an embodiment of the present invention is applied. It is the figure which showed an example of the shift pattern of a shift lever. It is a perspective view which shows the support structure of the fork shaft which concerns on embodiment of this invention. It is a front view of a support member concerning an embodiment of the present invention. It is the figure which showed a mode that the supporting member which concerns on embodiment of this invention was press-fit in the insertion hole by the side of a housing. It is a figure which shows the detail of the shape of the through-hole of the supporting member which concerns on embodiment of this invention. It is a figure which shows the detail of the state by which the fork shaft was inserted in the through-hole of the supporting member which concerns on embodiment of this invention. It is a figure which shows the detail of the shape of the through-hole of the supporting member which concerns on the modification of embodiment of this invention. It is a figure which shows the detail of the state by which the fork shaft was inserted in the through-hole of the support member which concerns on the modification of embodiment of this invention. It is a skeleton figure showing the main section of the direction of an axis of the conventional transmission. It is the figure which showed one of the conventional support structures which support the fork shaft with a rectangular cross section so that an axial direction movement is possible with respect to the housing of a transmission.

  Hereinafter, a vehicle manual transmission including a fork shaft support structure according to an embodiment of the present invention will be described with reference to the drawings. The manual transmission T / M includes five shift speeds (1st to 5th gears) for forward travel of the vehicle and one shift speed (reverse) for reverse travel of the vehicle.

(Constitution)
As shown in FIG. 1, the transmission T / M includes an input shaft Ai and an output shaft Ao. Both ends of the input shaft Ai are rotatably supported by a housing (case) Hg via a pair of bearings. Both ends of the output shaft Ao are rotatably supported by the housing Hg via a pair of bearings. The output shaft Ao is arranged in parallel with the input shaft Ai at a position shifted from the input shaft Ai. The input shaft Ai is connected to an output shaft of an engine E / G that is a drive source of the vehicle via a clutch C / T. The output shaft Ao is connected to drive wheels of the vehicle so that power can be transmitted.

  Hereinafter, a gear provided on the shaft so as not to be relatively rotatable is referred to as a “fixed gear”, and a gear provided on the shaft so as to be relatively rotatable is referred to as a “spinning gear”. The fixed gear is fixed so as not to be relatively rotatable on the shaft and not relatively movable in the axial direction by using one of known fitting methods. The idle gear is arranged so as to be rotatable relative to the shaft via a needle bearing, for example. Further, like the fixed gear, the hub is fixed so as not to be relatively rotatable on the shaft and not relatively movable in the axial direction by using one of known fitting methods. An (outer) spline is formed on the cylindrical outer peripheral surface of the hub.

  Between the pair of bearings on the input shaft Ai, the reverse drive gear GRi, the 5th speed drive gear G5i, the 4th speed drive gear G4i, the 3rd speed drive gear G3i, and the 2nd speed drive gear GRi are sequentially arranged from the left side in FIG. A drive gear G2i, a reverse drive gear GRi, and a first-speed drive gear G1i are coaxially provided. The drive gears GRi, G1i, G2i, G3i, G4i, G5i, GRi are all fixed gears. The drive gear GRi always meshes with an idle gear GRd provided on an idle shaft Ad arranged in parallel with the input shaft Ai.

  Between the pair of bearings on the output shaft Ao, the reverse driven gear GRo, the hub H3, the fifth-speed driven gear G5o, the fourth-speed driven gear G4o, the hub H2, and the third-speed driven are sequentially arranged from the left side in FIG. A gear G3o, a second-speed driven gear G2o, a hub H1, and a first-speed driven gear G1o are coaxially provided. The driven gears G1o, G2o, G3o, G4o, G5o are all idle gears.

  The driven gears G1o, G2o, G3o, G4o, G5o are always meshed with the drive gears G1i, G2i, G3i, G4i, G5i, respectively. The driven gear GRo always meshes with the idle gear GRd. That is, the reverse driven gear GRo is connected to the reverse drive gear GRi via the idle gear GRd.

  On the outer periphery of the hub H1, the sleeve S1 is always spline-fitted so as to be movable in the axial direction. When the sleeve S1 is in the position shown in FIG. 1 (disconnected position), the sleeve S1 is spline-fitted to both the first speed piece that rotates integrally with the driven gear G1o and the second speed piece that rotates integrally with the driven gear G2o. Do not match. When the sleeve S1 moves from the non-connection position to the right side position (first speed position) in the axial direction, the sleeve S1 is spline-fitted to the first speed piece and moves to the left side position (second speed position) in the axial direction. The sleeve S1 is splined to the second speed piece.

  On the outer periphery of the hub H2, a sleeve S2 is always spline-fitted so as to be movable in the axial direction. When the sleeve S2 is in the position shown in FIG. 1 (disconnected position), the sleeve S2 is splined to both the third speed piece that rotates integrally with the driven gear G3o and the fourth speed piece that rotates integrally with the driven gear G4o. Do not match. When the sleeve S2 moves from the non-connection position to the right side position (third speed position) in the axial direction, the sleeve S2 is spline-fitted to the third speed piece and moves to the left side position (fourth speed position) in the axial direction. The sleeve S2 is spline-fitted to the 4-speed piece.

  On the outer periphery of the hub H3, a sleeve S3 is always spline-fitted so as to be movable in the axial direction. When the sleeve S3 is in the position shown in FIG. 1 (disconnected position), the sleeve S3 is not spline-fitted to the 5-speed piece that rotates integrally with the driven gear G5o and the reverse piece that rotates integrally with the driven gear GRo. . When the sleeve S3 moves from the non-connection position to the right side position (5th speed position) in the axial direction, the sleeve S3 is spline-fitted to the 5th speed piece and moves to the left side position (reverse position) in the axial direction. The sleeve S3 is splined to the reverse piece.

  FIG. 2 shows an example of a shift pattern of a shift lever of a vehicle on which the transmission T / M is mounted. The axial positions of the sleeves S1, S2, S3 are respectively adjusted via corresponding fork shafts and forks (see FIG. 3 described later) that move in the axial direction in accordance with the shift operation of the shift lever. ing.

  As described above, in the transmission T / M, when the shift lever is in the neutral position (see FIG. 2), the sleeves S1, S2, and S3 are all adjusted to the non-connection position. As a result, a neutral state in which no power transmission system is formed between the input shaft Ai and the output shaft Ao is obtained. When the shift lever is shifted to the first speed position in the neutral state, the sleeve S1 moves to the first speed position. As a result, a power transmission system having a first gear reduction ratio is formed (first gear is established). When the shift lever is shifted to the second speed position in the neutral state, the sleeve S1 moves to the second speed position. As a result, a power transmission system having a speed reduction ratio of 2nd speed is formed (2nd speed is established).

  When the shift lever is shifted to the third speed position in the neutral state, the sleeve S2 moves to the third speed position. As a result, a power transmission system having a reduction ratio of 3rd speed is formed (3rd speed is established). When the shift lever is shifted to the fourth speed position in the neutral state, the sleeve S2 moves to the fourth speed position. As a result, a power transmission system having a reduction ratio of 4th speed is formed (4th speed is established).

  When the shift lever is shifted to the fifth speed position in the neutral state, the sleeve S3 moves to the fifth speed position. As a result, a power transmission system having a 5th speed reduction ratio is formed (5th speed is established). When the shift lever is shifted to the reverse position in the neutral state, the sleeve S3 moves to the reverse position. As a result, a power transmission system having a reverse reduction ratio is formed (reverse is established).

(Fork shaft support structure)
Hereinafter, a support structure for a fork shaft according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, three rod-like fork shafts A1, A2, A3 arranged in parallel and close to each other are supported by the housing Hg so as to be independently movable in the axial direction. The fork shafts A1, A2, and A3 are manufactured in the same shape by press molding, and each cross-sectional shape has the same rectangular shape (rectangular shape) having a height direction and a width direction orthogonal to each other. First, the operation of the fork shafts A1, A2, A3 will be briefly described.

  Shift heads H1, H2, and H3 are integrally connected to the fork shafts A1, A2, and A3, respectively. Further, forks F1, F2, and F3 are integrally connected to the four shafts A1, A2, and A3, respectively. Sleeves S1, S2, S3 (see FIG. 1) are integrally connected to the forks F1, F2, F3, respectively. That is, the fork F1 is involved in establishing the first and second gears, the fork F2 is involved in establishing the third and fourth gears, and the fork F3 is established in the fifth and reverse gears. Related.

  By selecting the shift lever at the neutral position by the driver of the vehicle, one shift head that engages with a shift inner lever (not shown) is selected from among the shift heads H1, H2, and H3. The selected shift head is pressed by the “shift inner lever that moves according to the shift operation of the shift lever by the driver” and moves in the axial direction. Thereby, the axial position of the corresponding one fork shaft (accordingly, the axial position of the fork and sleeve integral with the fork shaft) is adjusted. As a result, the gear stage requested by the driver is achieved.

  The fork shaft support structure according to the embodiment of the present invention includes a pair of resin support members P and P (see FIGS. 3 to 5) and a pair of insertion holes Hg1 and Hg1 (see FIG. 5). Composed. Each support member P has a short cylindrical shape. In each support member P, three identical through holes Q along the axial direction are formed side by side in the width direction at a predetermined interval. Each through hole Q has a rectangular shape that is slightly enlarged in a similar manner to the cross-sectional shape of the fork shaft. The outer peripheral surface (cylindrical surface) of each support member P surrounds three through holes Q.

  Each insertion hole Hg1 is a cylindrical recess formed on the inner surface of the housing Hg. That is, the inner peripheral surface of each insertion hole Hg1 is a cylindrical surface. Each insertion hole Hg1 may or may not penetrate. The inner diameter of the insertion hole Hg1 is slightly smaller (by the press-fitting allowance) than the outer diameter of the support member P. The pair of insertion holes Hg1, Hg1 are coaxially formed so as to face each other on the inner side surface of the housing Hg.

  The outer peripheral surface of each support member P is press-fitted and fixed in the corresponding insertion hole Hg1 (see FIG. 5). Thereafter, the end portions of the fork shafts corresponding to the three through holes Q of each support member P are inserted. As a result, as shown in FIG. 3, the three fork shafts A1, A2 and A3 arranged close to each other in parallel are axially and independently separated from the housing Hg via the pair of support members P and P. Is supported so as to be movable.

(Details of the shape of the through hole of the support member and the cross-sectional shape of the fork shaft)
On the inner peripheral surface of the through hole Q of the support member P, there are four surfaces connected through four corners. As shown in FIG. 6, among these four surfaces, two surfaces facing each other in the height direction of the through hole Q (vertical direction in FIG. 6) are P1 and P1, and the width direction of the through hole Q (in FIG. 6) Two surfaces facing each other in the lateral direction are P2 and P2. Further, the fork shafts A1, A2, and A3 are collectively referred to as “fork shaft A”.

  As shown in FIG. 6, in the support structure for a fork shaft of a transmission according to an embodiment of the present invention, the two surfaces P1 and P1 are convex surfaces that protrude inward and have a radius of curvature R1, and the two surfaces P2 , P2 are convex surfaces having a radius of curvature R2 projecting inward.

  On the other hand, the outer peripheral surface of the fork shaft A also has four surfaces connected via four corners. As shown in FIG. 7, in the support structure for a fork shaft of the transmission according to the embodiment of the present invention, two of these four surfaces face each other in the height direction of the fork shaft A (vertical direction in FIG. 7). (That is, two surfaces corresponding to the two surfaces P1 and P1) are flat surfaces, and two surfaces (that is, two surfaces P2) facing each other in the width direction of the fork shaft A (lateral direction in FIG. 7). , P2 corresponding to P2) is also a flat surface.

(Action / Effect)
Next, operations and effects of the fork shaft support structure of the transmission according to the embodiment of the present invention configured as described above will be described.

  As described above, in this support structure, all four surfaces on the inner periphery of the through hole Q are convex surfaces protruding inward, and all four surfaces on the outer periphery of the fork shaft A are flat. As a result, as can be understood from FIG. 7, in the vicinity of the four corners (edges) of the outer peripheral surface of the fork shaft A, the gap (gap) between the fork shaft A and the through hole Q becomes relatively large. Therefore, even if an external force in the torsional direction (see the arrow in FIG. 7) is applied around the axis of the fork shaft A for some reason and the fork shaft A is slightly inclined with respect to the through hole Q, the outer periphery of the fork shaft A The four corners (edges) of the surface do not touch the inner surface of the through hole Q (it is difficult). In other words, the situation that “the four corners (edges) of the outer peripheral surface of the fork shaft A come into contact with the inner surface of the through hole Q before the engaging portion between the fork and the sleeve comes into contact” does not occur (is difficult). That is, the above-described problem of “increase in sliding resistance of the sliding portion between the fork shaft and the through hole and increase in surface pressure of the sliding portion” due to this does not occur (is difficult). As a result, the fork shaft A can slide smoothly with respect to the support member P, and the driver's shift feeling does not deteriorate (is difficult).

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above embodiment, each support member P has three through holes Q for inserting three fork shafts. However, in each support member P, one fork shaft is inserted. One through hole may be formed.

  In the above embodiment, the support member P is press-fitted and fixed in the insertion hole Hg1, but the support member P may be fixed to the insertion hole Hg1 by a technique other than press-fitting. Moreover, although the outer peripheral surface of the supporting member P and the inner peripheral surface of the insertion hole Hg1 are comprised by the cylindrical surface, you may be comprised by surfaces other than a cylindrical surface. Moreover, a plate as shown in FIG. 11 may be employed as the support member.

  Further, the number of forward gears is not limited to five (for example, four or six may be used). The number of fork shafts and forks provided in the transmission changes according to the number of gears.

  Moreover, in the said embodiment, all four surfaces of the inner periphery of the through-hole Q of the support member P become a convex surface which protrudes inside, and all four surfaces of the outer periphery of the fork shaft A are all planes (FIG. 6). , See FIG. On the other hand, as shown in FIGS. 8 and 9, of the four inner circumferential surfaces of the through hole Q, the two surfaces P1 and P1 protrude outward and the radius of curvature becomes a concave surface of R1, and the two surfaces P2 , P2 is a convex surface having a radius of curvature R2 that protrudes inward, and of the four surfaces on the outer periphery of the fork shaft A, two surfaces facing each other in the height direction (vertical direction in FIG. 9) (that is, 2 Two surfaces corresponding to the two surfaces P1 and P1 are convex surfaces projecting outward, and two surfaces facing each other in the width direction of the fork shaft A (lateral direction in FIG. 7) (that is, the two surfaces P2 and P2). The two surfaces corresponding to P2 may be flat.

  Also by this modification, the same operation and effect as the above-mentioned embodiment can arise. In addition, in this modification, two surfaces (convex surfaces) facing each other in the height direction of the fork shaft and two surfaces P1, P1 (concave surfaces) of the through holes Q of the support member P are points (relatively small areas). ) Instead of a surface (relatively large area). As a result, compared to the above embodiment (the contact is a point contact), even if an external force is applied to the fork shaft in a direction that increases the contact surface pressure for some reason, the contact surface pressure is excessive. It ’s hard to be. As a result, the driver's shift feeling does not deteriorate (is difficult).

  Specifically, as shown in FIG. 3, in the configuration in which the shift head is attached to one of two surfaces facing each other in the height direction of the fork shaft and the fork is attached to the other, the shift head is axially moved by the shift inner lever. Is pressed in one direction (see black arrow in FIG. 3), the fork receives reaction force in the opposite axial direction from the corresponding sleeve (see white arrow in FIG. 3). Here, the shift head and the fork are separated. Therefore, a rotational moment is generated on the fork shaft. This rotational moment becomes an external force in the direction of increasing the contact surface pressure. However, for the reason described above, in this modification, the contact surface pressure described above is unlikely to be excessive as compared with the embodiment described above. Therefore, the driver's shift feeling is unlikely to deteriorate.

  T / M ... transmission, E / G ... engine, Ai ... input shaft, Ao ... output shaft, G1i, G2i, G3i, G4i, G5i, GRi ... drive gear, G1o, G2o, G3o, G4o, G5o, GRo ... Driven gear, H1 to H3 ... hub, S1 to S3 ... sleeve, A1, A2, A3 ... fork shaft, F1 to F3 ... fork, H1, H2, H3 ... shift head, P ... support member, Q ... through hole, Hg ... Housing (case), Hg1 ... Insertion hole

Claims (2)

A support structure for a fork shaft of a transmission that supports a fork shaft having a rectangular cross section that moves in an axial direction in response to a shift operation from a neutral position of a shift lever of a vehicle,
A pair of support members formed with rectangular through holes; and
A pair of attachment portions formed coaxially to face each other on the housing side of the transmission;
With
The pair of support members are respectively fixed to the pair of attachment portions, and both end portions of the fork shaft are inserted into the through holes of the pair of support members so as to be relatively movable in the axial direction, and the fork shaft is Supported axially movable with respect to the housing,
Of the four surfaces connected through the four corners of the outer peripheral surface of the fork shaft, the first set of two surfaces facing each other is a flat surface, and the second set of two surfaces facing each other is an outer surface, respectively. Is a convex surface protruding to
Of the four surfaces connected through four corners of the inner peripheral surface of the through hole of the support member, two surfaces corresponding to the first set are convex surfaces protruding inward and the second surface. A support structure for a fork shaft of a transmission, wherein two surfaces corresponding to the set are concave surfaces recessed outward. The support structure of the fork shaft of the transmission according to claim 1 ,
A plurality of the through holes are formed in each of the support members, and both end portions of the plurality of fork shafts are inserted into the plurality of through holes of the support members so as to be relatively movable in the axial direction, Support structure for transmission fork shaft.

Images