JP2014037883A - Support structure for fork shaft of transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique effective for smoothing operations of fork shafts in a shifting direction at a low cost, in a support structure for fork shafts of a transmission.SOLUTION: A support structure for fork shafts of a transmission comprises: shaft-extending portions provided to extend in a shifting direction to respective one-side end portions 110b, 120b and 130b of fork shafts 110, 120 and 130; cylindrical members extending to intersect the shifting direction and supporting the respective shaft-extended portions of the fork shafts 110, 120 and 130; and a shaft-like member 140 having a circular section, which is fixed to the housing of the transmission and inserted into the cylinders of the cylindrical members so as to support the cylindrical members relatively rotatably.

Description

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

  Japanese Patent Laying-Open No. 2012-7699 discloses an example of a vehicle transmission having a plurality of shift stages for forward movement. In this transmission, a fork shaft having a rectangular cross section extending in a long shape is used, and the fork shaft is supported by an opening of a support plate. Since the fork shaft with such a shape can be manufactured by pressing, it can be manufactured at a lower cost than a fork shaft having a circular cross-sectional shape manufactured by cutting, and is lighter and more compact. It has the advantage that it can be realized. On the other hand, when the fork shaft having a rectangular cross-sectional shape moves in the shift direction with respect to the opening of the support plate in accordance with the shift operation of the shift lever, the sliding resistance between the opening and the like is a factor. Smooth movement in the shift direction is hindered. However, measures to further process the opening of the support plate or add another member such as a bush so that the fork shaft can move smoothly in the shift direction cause an increase in cost.

JP 2012-7699 A

  Therefore, the present invention has been made in view of the above points, and provides a technique effective in facilitating the operation in the shift direction of a plurality of fork shafts at a low cost in a support structure for a fork shaft of a transmission. The purpose is to do.

  In order to achieve this object, a support structure for a fork shaft of a transmission according to the present invention is a structure that supports a plurality of fork shafts, and includes a shaft extension portion, a cylindrical member, and a shaft member. The plurality of fork shafts are independently moved in the shift direction according to the shift operation of the shift lever of the transmission and are arranged in parallel to each other. The shaft extension portion is provided to extend in the shift direction at each of one end portions of the plurality of fork shafts. The cylindrical member extends across the shift direction and supports each shaft extension portion of the plurality of fork shafts. The shaft-shaped member is a member having a circular cross section that is fixed to the transmission housing and is inserted into the cylinder of the cylindrical member so as to support the cylindrical member so as to be relatively rotatable. This shaft-like member may be directly fixed to the housing of the transmission, or may be indirectly fixed via another member.

  In the above support structure, the contact area between the shaft extending portion and the outer peripheral surface of the cylindrical member can be suppressed, and each of the plurality of fork shafts can be smoothly operated in the shift direction. In particular, it is preferable that the cylindrical member acts as a rolling element with or without sliding between the shaft extension portion. At this time, the smoothness of the operation of the fork shaft is not hindered even if the shaft extending portion is a shearing surface by press working. As a result, it is not necessary to perform further processing or add another member such as a bush to the shaft extension portion. In addition, since the sliding resistance during the operation of the fork shaft is suppressed, the shift efficiency by the shift lever is increased. Furthermore, since it is a relatively simple support structure using a cylindrical member and a shaft-like member, it is possible to suppress a significant increase in the number of parts.

  In the further form of the support structure according to the present invention, when any of the plurality of fork shafts moves in the shift direction, it is applied to the frictional force between the shaft extension portion of the fork shaft and the outer peripheral surface of the cylindrical member. The first friction coefficient preferably exceeds the second friction coefficient applied to the frictional force between the inner peripheral surface of the cylindrical member and the outer peripheral surface of the shaft-shaped member. Thereby, it becomes easy for a cylindrical member to roll a shaft extension part, and the sliding resistance at the time of operation | movement of a fork shaft can be suppressed more reliably.

  In a further form of the support structure according to the present invention, a plurality of cylindrical members are provided corresponding to the number of the plurality of fork shafts, and each of them individually supports the shaft extension portions of the plurality of fork shafts. It is preferable to be configured to do so. Thus, each of the plurality of fork shafts can be operated more smoothly in the shift direction.

  In a further form of the support structure according to the present invention, the plurality of fork shafts each preferably have a rectangular cross section and are arranged close to each other in the axial direction of the shaft-shaped member. As the rectangle here, a shape including a pair of first sides extending in parallel to each other and a pair of second sides orthogonal to the first side and extending in parallel to each other is a typical example. A shape having a chamfered shape between the side and the second piece is also included in the rectangle. Thereby, it becomes possible to arrange and support a plurality of fork shafts in a compact manner.

  In a further form of the support structure according to the present invention, it is preferable that the shaft extension portion is constituted by an inner wall surface of a long hole provided in each of the plurality of fork shafts so as to extend in the shift direction. Thereby, a shaft extension part can be formed in low cost by press work.

  As described above, according to the present invention, in the support structure for a fork shaft of a transmission, the operations in the shift direction of a plurality of fork shafts can be facilitated at low cost.

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 a figure which shows an example of the shift pattern of a shift lever. It is a perspective view which shows the support structure of the fork shafts 110, 120, 130 concerning embodiment of this invention. It is a front view of the edge part 110b, 120b, 130b of the fork shaft 110,120,130. It is a side view of the edge part 110b, 120b, 130b of the fork shaft 110,120,130. It is a schematic diagram explaining the load generation mechanism when any of the fork shafts 110, 120, and 130 moves in the shift direction. FIG. 3 is a perspective view showing a state in which only the fork shaft 120 is moved in the shift direction from the neutral position in order to achieve the third speed gear stage. In FIG. 7, it is the figure which looked at the edge part 110b, 120b, 130b of the fork shaft 110,120,130 from the side surface. In FIG. 8, the frictional force FA generated between the inner wall surface 121a on the upper side of the long hole 121 of the fork shaft 120 and the outer peripheral surface of the cylindrical member 142, and the first moment MA generated in the cylindrical member 142 by this frictional force FA. It is a figure for demonstrating. In FIG. 8, the frictional force FB generated between the inner peripheral surface of the cylindrical member 142 and the outer peripheral surface of the shaft-shaped member 140 and the second moment MB generated in the cylindrical member 142 due to the frictional force FB are illustrated. FIG. FIG. 3 is a perspective view showing a state in which only the fork shaft 110 is moved in the shift direction from the neutral position in order to achieve the second speed gear stage. In FIG. 11, it is the figure which looked at the edge part 110b, 120b, 130b of the fork shaft 110,120,130 from the side surface.

  Hereinafter, a manual transmission for a vehicle 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.

  As shown in FIG. 1, the (manual) 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 (also referred to as “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 disposed in parallel with the input shaft Ai at a position deviated 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 D / W of the vehicle so that power can be transmitted.

  Between the pair of bearings on the input shaft Ai, the reverse R drive gear GRi, the fifth speed drive gear G5i, the fourth speed drive gear G4i, the third speed drive gear G3i, and the second speed are arranged in order from the left side in FIG. Drive gear G2i, reverse R drive gear GRi, and first-speed drive gear G1i are provided coaxially. 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 R 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 are sequentially arranged from the left side in FIG. A driven 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 R driven gear GRo is connected to the reverse R 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 response to a shift operation in the shift direction SF of the shift lever. It has become so.

  As described above, in the transmission T / M, when the shift lever is in the neutral position NP (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).

  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 fork shafts 110, 120, and 130 extending in a long shape in the first direction X are to be supported.

  As shown in FIG. 3, each of the fork shafts 110, 120, and 130 is a flat plate member that is manufactured in the same shape by pressing using a press machine (also referred to as “shearing”), and more specifically, Each cross-sectional shape is the same rectangular shape (rectangle) having a width direction and a height direction orthogonal to each other. The corners of each fork shaft are appropriately chamfered. That is, the rectangle includes a pair of first sides extending in parallel with each other and a pair of second sides orthogonal to the first side and extending in parallel with each other, and the first side and the second piece Is defined as a shape with a chamfered shape. The fork shafts 110, 120, and 130 here correspond to “a plurality of fork shafts” of the present invention.

  In the drawings of the present specification, the longitudinal direction of the fork shafts 110, 120, 130 is the first direction X, the width direction of the fork shafts 110, 120, 130 is the second direction Y, and the height of the fork shafts 110, 120, 130 is high. The vertical direction is defined as the third direction Z. The fork shafts 110, 120, and 130 are arranged in parallel and adjacent to each other with respect to the second direction Y, and are independently movable in the first direction X while being supported with respect to the housing Hg. Yes. First, the operation of the fork shafts 110, 120, 120 will be briefly described.

  Shift heads 211, 221, and 231 are integrally connected to the fork shafts 110, 120, and 130, respectively. Further, forks 210, 220, and 230 are integrally connected to the four shafts 110, 120, and 130, respectively. Sleeves S1, S2, S3 (see FIG. 1) are integrally connected to the forks 210, 220, 230, respectively. That is, the fork 210 is related to the establishment of the first and second gears, the fork 220 is related to the establishment of the third and fourth gears, and the fork 230 is related to the establishment of the fifth and reverse gears.

  By selecting the shift lever at the neutral position NP by the driver of the vehicle, one shift head that engages with the shift inner lever (not shown) is selected from among the shift heads 211, 221, and 231. The selected shift head is pressed by a shift inner lever (a member that moves in response to a 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.

  Fork shafts 110, 120, and 130 having the above-described configuration are all supported by support members 150 and 160 fixed to housing Hg, shaft-like member 140 supported by support member 160, and shaft-like member 140. The cylindrical members 141, 142, and 143 are supported by the housing Hg. That is, the shaft member 140, the cylindrical members 141, 142, and 143 and the support members 150 and 160 constitute a fork shaft support structure. The shaft-shaped member 140 is typically configured as a shaft member or a rod-shaped pin member having a circular cross section, and is formed into a columnar shape or a cylindrical shape by cutting using a cutting tool. In this case, typically, the cutting process can obtain a surface structure having a higher surface roughness than the press process (a surface structure having a small friction coefficient). The shaft-like member 140 extends in a long shape in the second direction Y in the assembled state. A part of the shaft-like member 140 may be constituted by a member such as a bolt. The shaft-like member 140 here corresponds to the “shaft-like member” of the present invention. The cylindrical members 141, 142, and 143 are typically configured as support rollers having the same shape, and are formed into a cylindrical shape by cutting using a cutting tool. The cylindrical members 141, 142, and 143 here correspond to the “cylindrical member” of the present invention. Both the support members 150 and 160 are manufactured by press working using a press machine in the same manner as the fork shaft.

  The support member 150 is configured as a flat support plate, and includes a through-hole support opening 151 into which the three fork shafts 110, 120, and 130 can be inserted in common. Accordingly, the end portions 110 a, 120 a, and 130 a of the fork shafts 110, 120, and 130 are supported by being inserted into the support openings 151 of the support member 150. In this case, it is preferable that the opening area of the support opening 151 substantially matches the sum of the cross-sectional areas of the three fork shafts 110, 120, and 130.

  As shown in FIG. 4, the support member 160 is configured by the housing Hg of the transmission itself or by members (standing walls 161 and 162) fixed to the housing Hg, and is attached through the member. Holes 163 and 164 are provided. The standing walls 161 and 162 may be integrated and fixed to the housing Hg, or may be separately fixed to the housing Hg. The mounting holes 163 and 164 have the same inner diameter as the outer diameter of the shaft-shaped member 140 having a circular cross section. The shaft-shaped member 140 is inserted into the mounting holes 163 and 164 of the standing walls 161 and 162. Is fixed to the housing Hg. After the housing Hg is mounted, the fork shafts 110, 120, and 130 can be positioned by inserting the support pins 170 into the mounting holes 163 and 164 of the standing walls 161 and 162 from the outside of the housing Hg. Assembly is improved.

  On the other hand, as shown in FIG. 5, the end portions 110b, 120b, and 130b of the fork shafts 110, 120, and 130 are elongated holes 111 and 121 that extend through the fork shaft and extend in the first direction X, respectively. 131 is formed. Each of the long holes 111, 121, and 131 has a height dimension in the third direction Z that is the same as or slightly larger than the outer diameter of the cylindrical cylindrical members 141, 142, and 143 having a circular cross section. The first direction X extends in a long shape. Each of the long holes 111, 121, and 131 has two inner wall surfaces 111a, 121a, and 131a that extend in parallel to the shift direction (first direction X) of the fork shafts 110, 120, and 130, respectively. Of these, the shaft extension portions 111a, 121a, and 131a that are one inner wall surface (also referred to as “upper inner wall surface”) 111a, 121a, and 131a located above the cylindrical members 141, 142, and 143 are cylindrical members 141, 142, and 143. It is supported by abutting on the outer peripheral surface. The shaft member 140 is inserted into the cylinder of the cylindrical member so as to support each of the cylindrical members 141, 142, and 143 so as to be relatively rotatable. Accordingly, the end portions 110b of the fork shafts 110, 120, and 130 are inserted in the space 165 formed between the standing walls 161 and 162 of the support member 160, and the fork shafts 110, 120, and 130 are inserted. 120b and 130b are supported by cylindrical members 141, 142, and 143 (see FIG. 4). In addition, instead of using the three cylindrical members 141, 142, and 143, the fork shafts 110, 120, and 130 can be supported using two or less, or four or more cylindrical members.

  Hereinafter, the effect of the fork shaft support structure having the above configuration will be described with reference to FIGS.

  As shown in FIG. 6, according to the shift operation from the neutral position of the shift lever, a load in the shift direction indicated by the white arrow in the figure acts on one of the shift heads 211, 221, and 231. As a result, any of the fork shafts 110, 120, and 130 moves in the shift direction (the first direction X or the opposite direction). In this case, the shift heads 211, 221, and 231 to which the load in the shift direction acts are close to the support member 150 side with respect to the first direction X, and are third from the reference line L in the shift direction passing through the shaft-like member 140. Since one of the fork shafts 110, 120, and 130 moves in the shift direction because it is at a position deviated in the direction Z, a counterclockwise load (moment) in FIG. 6 acts on the fork shaft. That is, when the shift heads 211, 221, and 231 are “force points”, the contact portion between the support opening 151 of the support member 150 and the fork shaft becomes the “fulcrum”, and the upper side of the long holes 111, 121, and 131 of the fork shaft. A contact portion between any one of the inner wall surfaces 111a, 121a, and 131a and the outer peripheral surface of the corresponding cylindrical member is an “action point”.

  As shown in FIGS. 7 and 8, for example, in order to achieve a third speed, only the fork shaft 120 of the three fork shafts 110, 120, and 130 has a predetermined shift direction (the white line in FIG. 7). Move in the direction of the arrow). In this case, as shown in FIG. 9, the frictional force FA generated between the upper inner wall surface 121 a of the long hole 121 of the fork shaft 120 and the outer peripheral surface of the cylindrical member 142 has a friction coefficient μA and a vertical drag NA. Is determined by the product of Here, the coefficient of friction μA indicates the difficulty of slipping between the inner wall surface 121a of the long hole 121 that is a shear surface and the outer peripheral surface of the cylindrical member 142 that is a cutting surface. Therefore, the first moment MA for rotating the cylindrical member 142 in the counterclockwise direction (the direction of the arrow R1 in FIG. 8) by the frictional force FA is the frictional force FB and the outer peripheral radius LA of the cylindrical member 142. Determined by the product of As shown in FIG. 10, the frictional force FB generated between the inner peripheral surface of the cylindrical member 142 and the outer peripheral surface of the shaft-like member 140 is determined by the product of the friction coefficient μB and the normal force NB. . Here, the friction coefficient μB indicates the difficulty of slipping between the inner peripheral surface of the cylindrical member 142 that is a cutting surface and the outer peripheral surface of the shaft-shaped member 140 that is a cutting surface. Therefore, the second moment MB for rotating the cylindrical member 142 clockwise by this frictional force FB (the direction opposite to the arrow R1 in FIG. 8) is the frictional force FB and the inner peripheral radius of the cylindrical member 142. It is determined by the product of LB. On the other hand, since the mass of the cylindrical member 142 is typically much lower than the mass of the fork shaft 120, the normal force NA and the normal force NB are substantially equal.

  As a result, the moment M for rotating the cylindrical member 142 in the counterclockwise direction is determined by NA × (μA × LA−μB × LB), which is the difference between the first moment MA and the second moment MB. . At this time, the friction coefficient μA applied to the combination of the shearing surface and the cutting surface is equal to or higher than the friction coefficient μB applied to the combination of the cutting surfaces (μA ≧ μB), and the outer peripheral radius LA exceeds the inner peripheral radius LB (LA > LB). Therefore, the moment M is positive, and the cylindrical member 142 always rotates counterclockwise (the direction of the arrow R1 in FIG. 8).

  As shown in FIGS. 11 and 12, for example, in order to achieve a second speed, only the fork shaft 110 of the three fork shafts 110, 120, and 130 has a predetermined shift direction (the white line in FIG. 12). Move in the direction of the arrow). In this case, both the first moment MA and the second moment MB acting on the cylindrical member 141 act in the opposite direction to the case of FIG. As a result, the cylindrical member 141 always rotates in the clockwise direction (the direction of the arrow R2 in FIG. 12).

  According to the fork shaft support structure having the above-described structure, the fork shafts 110, 120, and 130 are all manufactured at low cost by press working, and then operate smoothly in the shift direction using the cylindrical members 141, 142, and 143. Can be made. As a result, a cost-effective fork shaft support structure can be realized.

  That is, it is possible to suppress the contact area between the inner wall surfaces 111a, 121a, 131a on the upper side of the long holes 111, 121, 131 and the outer peripheral surfaces of the cylindrical members 141, 142, 143. At this time, even if the inner wall surfaces 111a, 121a, 131a of the long holes 111, 121, 131 are sheared surfaces by press working, the smooth operation in the shift direction of the fork shafts 110, 120, 130 is not hindered. In addition, the inner wall surfaces 111a, 121a, 131a on the upper side of the long holes 111, 121, 131 are independently supported by the cylindrical members 141, 142, 143 provided corresponding to the number of the fork shafts 110, 120, 130. Thus, each of the fork shafts 110, 120, and 130 can be smoothly operated in the shift direction. As a result, there is no need to further process the inner wall surface or add another member such as a bush.

  Moreover, since the sliding resistance at the time of the operation | movement of the fork shaft 110,120,130 in the shift direction is suppressed, the shift efficiency by a shift lever increases. In particular, the upper inner wall surfaces 111 a, 121 a, 131 a of the long holes 111, 121, 131 are strongly pressed against the outer peripheral surfaces of the cylindrical members 141, 142, 143. When any of the fork shafts 110, 120, and 130 moves in the shift direction, the first friction coefficient (the first friction coefficient applied to the frictional force between the inner wall surface above the long hole of the fork shaft and the outer peripheral surface of the cylindrical member ( The aforementioned friction coefficient μA) is set so as to exceed the second friction coefficient (the aforementioned friction coefficient μB) applied to the frictional force between the inner peripheral surface of the cylindrical member and the outer peripheral surface of the shaft-shaped member 140. Thus, the cylindrical member can easily roll on the inner wall surface on the upper side of the long hole. As a result, the sliding resistance during the operation of each of the fork shafts 110, 120, and 130 can be more reliably suppressed.

  Further, by arranging the fork shafts 110, 120, and 130 close to each other in the axial direction of the shaft-shaped member 140, the fork shafts 110, 120, and 130 can be arranged and supported in a compact manner.

  Furthermore, since it is a relatively simple support structure using the shaft-shaped member 140 and the cylindrical members 141, 142, and 143, it is possible to suppress a significant increase in the number of parts.

  The present invention is not limited to the above exemplary embodiment, and various applications and modifications are possible. For example, each of the following embodiments to which the above embodiment is applied can be implemented.

  In the above embodiment, the shaft extending portions supported by the cylindrical members 141, 142, and 143 in the fork shafts 110, 120, and 130, respectively, are elongated holes having two inner wall surfaces that extend in parallel to the shift direction. Although (closed shape) is used, in the present invention, the shaft extending portion can be configured by a portion having only one extending surface extending in the shift direction instead of the long hole.

  In the above-described embodiment, the case where the fork shafts 110, 120, and 130 are disposed close to each other in the axial direction of the shaft-shaped member 140 has been described. However, in the present invention, each of the fork shafts 110, 120, and 130 is predetermined. They may be arranged at intervals.

  In the above embodiment, the case where the support structure of the present invention is applied to support only one end portion 110b, 120b, 130b of the fork shafts 110, 120, 130 has been described. The support structure of the present invention can be applied to the support of the part.

  In the above-described embodiment, the case where the fork shafts 110, 120, and 130 have a shape having a rectangular cross section has been described, but the fork shaft having a cross-sectional shape other than a rectangle (for example, a circle, an ellipse, a triangle, a polygon, etc.). The present invention can also be applied to the supporting structure.

  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.

  T / M ... transmission, E / G ... engine, C / T ... clutch, D / W ... drive wheel, Ai ... input shaft, Ao ... output shaft, G1i, G2i, G3i, G4i, G5i, GRi ... drive gear G1o, G2o, G3o, G4o, G5o, GRo ... driven gear, H1-H3 ... hub, S1-S3 ... sleeve, Hg ... housing (case), 110, 120, 130 ... fork shaft, 110a, 110b, 120a, 120b, 130a, 130b ... end, 111, 121, 131 ... elongated hole, 111a, 121a, 131a ... inner wall surface, 140 ... axial member, 141, 142, 143 ... cylindrical member, 150, 160 ... support member, 151: Support opening, 161, 162 ... Standing wall, 163, 164 ... Mounting hole, 165 ... Space, 210, 220, 230 ... Fork, 211, 221 231 ... Shift head

Claims (5)

A support structure for a fork shaft of a transmission that supports a plurality of fork shafts that are independently moved in the shift direction and that are arranged in parallel with each other according to a shift operation of a shift lever of the transmission,
A shaft extension portion provided to extend in each of the one end portions of the plurality of fork shafts in the shift direction;
A cylindrical member that extends across the shift direction and supports the shaft extension of each of the plurality of fork shafts;
A shaft-shaped member having a circular cross section that is fixed to the transmission housing and inserted into a cylinder of the cylindrical member so as to support the cylindrical member in a relatively rotatable manner;
A support structure for a fork shaft of a transmission. The support structure for a fork shaft of a transmission according to claim 1,
When any one of the plurality of fork shafts moves in the shift direction, the first friction coefficient applied to the frictional force between the shaft extension portion of the fork shaft and the outer peripheral surface of the cylindrical member is A support structure for a fork shaft of a transmission that exceeds a second friction coefficient applied to a frictional force between an inner peripheral surface of a cylindrical member and an outer peripheral surface of the shaft-shaped member. A support structure for a fork shaft of a transmission according to claim 1 or 2,
A plurality of the cylindrical members are provided corresponding to the number of the plurality of fork shafts, and each of the cylindrical members separately supports the shaft extension portion of each of the plurality of fork shafts. Support structure. A support structure for a fork shaft of a transmission according to any one of claims 1 to 3,
The fork shaft support structure of a transmission, wherein each of the plurality of fork shafts has a rectangular cross section and is disposed close to each other in the axial direction of the shaft-shaped member. A support structure for a fork shaft of a transmission according to any one of claims 1 to 4,
The shaft extending portion is a support structure for a fork shaft of a transmission, which is configured by an inner wall surface of a long hole provided in each of the plurality of fork shafts so as to extend in the shift direction.

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