JP6485947B2 - Vehicle transmission - Google Patents

Description

  The present invention relates to a vehicle transmission provided with a sleeve gear supported by a shifter fork and moving in the axial direction together with the shifter fork.

  2. Description of the Related Art Conventionally, a continuously meshing vehicle transmission is known as a transmission used in a vehicle. This always-meshing type transmission includes an output shaft to which a drive shaft is connected, a step gear such as a third gear, a second gear, a low gear, and the like that are mounted in an idle state on the output shaft, and adjacent to the step gear. The main member is a dog gear that is provided coaxially and has external teeth, a clutch hub that rotates in the same manner as the output shaft, and a sleeve gear that is fitted on the outer periphery of the clutch hub with, for example, spline teeth on the inner periphery. Configured as

  In this vehicle transmission, the outer periphery of the sleeve gear is supported by a shifter fork, and when the sleeve gear is moved in the axial direction together with the shifter fork, the inner teeth of the sleeve gear mesh with the outer teeth of the dog gear, and the gear is inserted. Is configured to complete.

  Also, it is known that such transmissions sometimes lose gear after being engaged. This gear loss phenomenon is a phenomenon in which the dog gear and the sleeve gear are disengaged during traveling. When this gear loss occurs, power transmission is interrupted.

  The mechanism of gear loss is complex, but in recent years, measurement technology and simulation technology have evolved, and research using them has gradually revealed the cause of gear loss (for example, (Refer nonpatent literature 1.). The results of actual machine tests in this study indicate that the behavior of sleeve gears and dog gears during operation is being clarified.

  That is, in this research, the step gear is a helical gear whose teeth formed on the outer periphery thereof are inclined with respect to the output shaft. Therefore, when torque is input, the step gear and the dog gear are According to the influence of the thrust load due to the torsion angle, the rotation is inclined by the radial gap between the step gear and the output shaft.

  Then, when the step gear is inclined and rotated with respect to the output shaft, as shown in FIG. 7, the sleeve gear 6 meshing with the dog gear 7 is inclined in a top view, and as shown in FIG. The center of rotation of both the dog gear 7 and the sleeve gear 6 is deviated, and the contact load distribution between the dog gear 7 and the sleeve gear 6 is not uniform in the circumferential direction. Here, reference numeral 8 in the figure denotes a shifter fork 8 that supports the sleeve gear 6 from the outer periphery.

  Further, when the step gear 4 is tilted and rotated with respect to the output shaft 3, the meshing region in the circumferential direction of the dog gear 7 and the sleeve gear 6 from the geometrical relationship, It is assumed that the contact load is divided into extrusion regions that act in the gear release direction. In the vehicular transmission in which gear disengagement frequently occurs, as shown in FIG. 8, the dog gear 7 is displaced with respect to the sleeve gear 6 so that a large contact load is generated in the push-out region, and is in contact with the pull-back region. Some parts are not seen.

  Here, conventionally, as a mechanism for preventing such gear disengagement, a taper mechanism of a spline meshing portion that inclines the contact surface between the outer teeth of the dog gear 7 and the inner teeth of the sleeve gear 6 (see, for example, Patent Document 1). ), And a lock ball mechanism (for example, see Patent Document 2) that prohibits movement of the shifter rod on which the shifter fork 8 is supported has been proposed.

Automotive Engineering Society Academic Lecture Preprint, 20145212 No. 65-14

Japanese Patent Laid-Open No. 04-362314 JP 2003-120808 A

  However, even with the conventional spline meshing portion taper mechanism and lock ball mechanism, gear disengagement sometimes occurs and no drastic measures have been taken. For this reason, the research in Non-Patent Document 1 utilizing the measurement technique and the simulation technique reveals a different concept from the taper mechanism and the lock ball mechanism of the conventional spline meshing portion, etc. Means to suppress gear loss have been demanded.

  An object of the present invention is to provide a vehicle transmission capable of effectively suppressing gear loss based on a different concept from the conventional one.

The present invention is provided integrally with an output shaft, a step gear having external teeth that are provided relative to the output shaft and inclined with respect to the output shaft, a dog gear that is provided coaxially adjacent to the step gear, and A clutch hub, a sleeve gear provided on the clutch hub so as to be slidable in the axial direction and configured so that the inner teeth can be engaged with the outer teeth of the dog gear, and a pair of members for supporting the sleeve gear sandwiched from both sides in the radial direction This is an improvement of a vehicle transmission including a shifter fork formed with a piece .

The characteristic configuration is that one of the pair of engaging pieces is displaced in the axial direction of the output shaft to support the sleeve gear so as to incline with respect to the output shaft, and the sleeve in the region where the dog gear and the gear-engaging force are generated The gear is in contact.

  In the vehicle transmission according to the present invention, since the sleeve gear is tilted so that the sleeve gear is brought into contact with the dog gear in the region where the gear engagement force is generated, the contact load is mainly concentrated in the region where the dog gear and the gear engagement force is generated. Will do. As described above, the load is transmitted by concentrating the contact load, thereby generating a load in the step gear direction in the sleeve gear and preventing the sleeve from moving away from the step gear. This prevents so-called gear slippage, which is a phenomenon in which the sleeve is moved away from the step gear and the dog gear and the sleeve gear are disengaged.

It is a top view which shows the relationship between the sleeve gear in the transmission of this invention embodiment, a shift fork, and a dog gear. It is a front view which shows the relationship between the stage gear, a drive gear, a sleeve gear, a shift fork, and a dog gear. FIG. 3 is a view when FIG. 2 showing the meshing state of the dog gear and the sleeve gear is viewed from the C direction. It is the BB sectional view taken on the line of FIG. 6 which shows the state in which the sleeve gear is supported by the shifter fork. FIG. 7 is an enlarged view of a portion A in FIG. 6 showing a state where the sleeve gear meshes with the dog gear and the gear is engaged. It is a longitudinal cross-sectional view of the transmission of embodiment of this invention. It is a top view corresponding to FIG. 1 which shows the relationship between the sleeve gear in the conventional transmission, a shift fork, and a dog gear. FIG. 4 is a view corresponding to FIG. 3 illustrating a meshing state of a dog gear and a sleeve gear in the conventional transmission.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 6 shows a vehicle transmission 10 according to the present invention. This transmission is a constantly meshing mechanical transmission 10. The mechanical transmission 10 in this embodiment includes a gear case 11, an input shaft 12 provided in the gear case 11, and an input shaft 12. And an output shaft 13 provided coaxially with the input shaft 12, and a plurality of step gears 14 such as a third gear, a second gear, and a low gear that are supported by the output shaft 13 and idle around the output shaft 13. With.

  The gear case 11 is provided with a counter shaft 16 below the output shaft 13 in parallel with the output shaft 13, and a plurality of drive gears 17 are integrally formed on the counter shaft 16. A counter drive gear 17 h provided at the head of the counter shaft 16 meshes with a speed gear 12 a formed on the input shaft 12, whereby the counter shaft 16 is configured to rotate together with the input shaft 12. Further, the plurality of step gears 14 rotatably supported on the output shaft 13 are always meshed with any one of the drive gears 17 formed on the counter shaft 16, and the output shaft 13 between each of the plurality of step gears 14. Are each provided with a disc-shaped clutch hub 18 integrally therewith. A spline extending in the axial direction is formed on the outer periphery of the plurality of clutch hubs 18, and a sleeve gear 19 is slidably provided on the spline.

  Further, in this mechanical transmission 10, a plurality of shifter rods 21 (only one is shown in the figure) parallel to the output shaft 13 are provided above the output shaft 13 so as to be movable in the longitudinal direction. 21, the upper ends of the shifter forks 22 are respectively attached. The lower portion of the shifter fork 22 is connected to the sleeve gear 19. By selectively moving the shifter rod 21 in the axial direction, the shifter fork 22 that moves together with the moving shifter rod 21 is connected to the lower end of the sleeve gear 19. Is configured to slide in the axial direction. For this reason, when the shifter rod 21 moves in the axial direction, the shifter fork 22 moves forward or backward together with the sleeve gear 19 together with the shifter rod 21. As a result, the gear removal operation and the desired gear engagement operation are performed.

  Since the structure around the sleeve gear 19 that moves together with the shifter fork 22 is substantially the same structure, one of them will be described as a representative.

  Then, as shown in detail in FIG. 4, the sleeve gear 19 is provided on the clutch hub 18, and this clutch hub 18 has a ring shape and is fitted and fixed to the output shaft 13. Rotation and axial movement are impossible. A spline extending in the axial direction forming the outer teeth 18a is formed on the outer periphery of the clutch hub 18.

  On the other hand, the sleeve gear 19 has a ring shape, and a spline 19 a that meshes with the outer teeth 18 a on the outer periphery of the clutch hub 18 is formed on the inner periphery. This spline forms the inner teeth 19 a of the sleeve gear 19. Further, a groove 19b in which the shifter fork 22 is engaged is formed in the outer periphery of the sleeve gear 19 in the circumferential direction.

  As shown in FIG. 5, the step gear 14 is rotatably fitted to the output shaft 13 adjacent to the clutch hub 18, and the dog gear 31 is adjacent to the step gear 14 on the side facing the clutch hub 18. It is provided coaxially. On the outer periphery of the step gear 14, teeth 14 a that mesh with the drive gear 17 (FIG. 6) of the countershaft 16 are formed to be inclined with respect to the output shaft 13.

  On the other hand, the dog gear 31 includes external teeth 31a formed on the outer periphery thereof, and a tapered cone 31c having a smaller diameter toward the clutch hub 18 is formed. The taper cone 31c is fitted with a synchronizer ring 32 having an inclined surface that matches the conical surface on the inner periphery. The outer teeth 18a of the clutch hub 18 and the outer teeth 31a of the dog gear 31 have the same outer periphery and circumferential pitch, and can be engaged with the inner teeth 19a formed of the splines of the sleeve gear 19 alone or in series. Configured. Then, as shown in FIG. 5B, the sleeve gear 19 moves in the axial direction, and the gear engagement is completed when the inner teeth 19a of the sleeve gear 19 mesh with the outer teeth 31a of the dog gear 31. Is done.

  The sleeve gear 19 is held between the shifter forks 22 (FIG. 4). An engagement piece 22a that can enter a concave groove 26b formed on the outer periphery of the sleeve gear 19 is formed on the shifter fork 22, and when the shifter fork 22 is moved in the axial direction of the output shaft 13, the sleeve gear 19 also moves along the axis. Configured to move in the direction.

  As shown in FIG. 1, the characteristic configuration of the present invention is that the shifter fork 22 supports the sleeve gear 19 so as to be inclined with respect to the output shaft 13, and the dog gear 31 and the gear engaging force are generated. The sleeve gear 19 is tilted so as to contact the sleeve gear 19.

  Here, the region where the dog gear 31 and the gear-engaging force are generated is a part of the region where the dog gear 31 and the sleeve gear 19 are engaged in the circumferential direction when the step gear 14 rotates while being inclined with respect to the output shaft 13. This is a region where the contact load between the dog gear 31 and the sleeve gear 19 acts in the gear setting direction.

  According to recent research, the region where this gear-engaging force is generated is formed to be biased to either the left or right (upper or lower side in the figure) of the dog gear 31 in a top view as shown in FIG. When a region where the gear engagement force is generated is formed on the lower side of the figure, the shifter fork 22 that brings the engagement piece 22a supporting the sleeve gear 19 on the side where the region is formed closer to the dog gear 31 side is provided. The sleeve gear 19 is tilted and supported by such a shifter fork 22.

  The shifter fork 22 shown in FIG. 1 is such that the engagement piece 22a on the lower side of the drawing approaches the dog gear 31 side, and even if the upper side of the sleeve gear 19 in the drawing is inclined so as to approach the dog gear 31, As indicated by the chain line, the sleeve gear 19 is exemplified to support the dog gear 31 so as to remain substantially parallel.

  Next, the operation of the vehicle transmission configured as described above will be described.

  In order to engage the gear from the gear disengaged state of FIG. 5A, the shifter fork 22 is moved in parallel with the output shaft 13. The moving shifter fork 22 moves the sleeve gear 19 shown in FIG. 5 in the axial direction. At this time, the force applied to the sleeve gear 19 strongly presses the synchronizer ring 32 against the tapered cone 31c of the dog gear 31, and a strong synchronizing action (synchronizing action) is performed by the friction force. If the rotational speeds of the sleeve gear 19 and the dog gear 31 are equalized by this synchronizing action, the synchronization is thereby completed.

  Then, as shown in FIG. 5B, the sleeve gear 19 further moves to the dog gear 31 side, and the inner teeth 19a inside the moving sleeve gear 19 pushes away the outer peripheral gear teeth 32a of the synchronizer ring 32 and advances. The outer teeth 31a of the 31 are engaged with each other. This completes the gearing of the transmission.

  Thus, when the dog gear 31 and the sleeve gear 19 are engaged with each other and the gear engagement is completed, the rotation of the input shaft 12 rotates the counter shaft 16 and the drive gear 17 provided on the counter shaft 16 also rotates. The step gear 14 that meshes with the output shaft 13 rotates. As a result, the power input to the input shaft 12 can be transmitted to the output shaft 13.

  Here, from the research results utilizing measurement technology and simulation technology in recent years, the stepped gear 14 employs a helical gear in which the teeth 14a formed on the outer periphery thereof are inclined with respect to the output shaft 13. As shown in FIG. 2, when torque is input by meshing with the drive gear 17, the step gear 14 and the dog gear 31 are affected by the thrust load due to the torsion angle of the step gear 14, and the step gear 14, the output shaft 13, It will rotate by the amount of the radial gap in between.

  When the step gear 14 is tilted and rotated, as shown in FIG. 3, the contact force between the dog gear 31 and the sleeve gear 19 is generated in different directions in the two regions because of the geometrical relationship. That is, the arbitrary point D on the dog gear 31 in FIG. 2 repeats displacement in the positive and negative directions in the axial direction as the step gear 14 rotates due to the inclination.

  Here, if the area where the point D is displaced toward the plus side in FIG. 2 is the pull-back area, and the area where the point D is displaced toward the minus side in FIG. 2 is the push-out area, the dog gear 31 moves in the plus direction in the pull-back area. Due to the displacement, a positive load is also generated in the sleeve gear 19.

  On the other hand, since the dog gear 31 is displaced in the minus direction in the push-out region, a load in the minus direction is also generated in the sleeve gear 19. A pull-back area that generates a load in the positive direction that is the direction of the step gear 14 on the sleeve gear 19 is an area in which contact force is generated in the gear engagement direction, and a load in the negative direction that is a direction away from the step gear 14 to the sleeve gear 19. The push-out area that generates the pressure is the area where the contact force is generated in the gear disconnection direction.

  In the present invention, as shown in FIG. 1, the shifter fork 22 supports the sleeve gear 19 to be inclined with respect to the output shaft 13. Then, the sleeve gear 19 is tilted so that the sleeve gear 19 is brought into contact with the dog gear 31 in a region where the gear engagement force is generated.

  That is, when the step gear 14 is inclined and rotated with respect to the output shaft 13 in the front view shown in FIG. 2, the sleeve gear 19 that meshes with the dog gear 31 is inclined in the top view shown in FIG. As described above, the rotational centers of both the dog gear 31 and the sleeve gear 19 are deviated from the geometric relationship, and the contact load distribution between the dog gear 31 and the sleeve gear 19 is not uniform in the circumferential direction.

  In the present invention, it means that the sleeve gear 19 is engaged with the dog gear 31 so that the contact load is mainly concentrated in the region where the gear engagement force is generated with the dog gear 31 by tilting the sleeve gear 19.

  As described above, in the present invention, the sleeve gear 19 is tilted and the contact load is concentrated in the region where the dog gear 31 and the gear insertion force are generated to transmit the load, so that the sleeve gear 19 is always in the direction of the step gear 14. A positive load is generated, thereby preventing the sleeve 19 from moving away from the step gear 14. As a result, it is possible to prevent so-called gear disengagement, which is a phenomenon in which the sleeve 19 moves away from the step gear 14 and the dog gear 31 and the sleeve gear 19 are disengaged.

DESCRIPTION OF SYMBOLS 10 Transmission 13 Output shaft 14 Step gear 18 Clutch hub 19 Sleeve gear 19a Internal tooth 22 Shifter fork 31 Dog gear 31a External tooth

Claims (1)

A step gear (14) having external teeth inclined relative to the output shaft (13) provided so as to be rotatable relative to the output shaft (13), and a dog gear provided coaxially adjacent to the step gear (14) (31), a clutch hub (18) provided integrally with the output shaft (13), and an internal tooth (19a) provided on the clutch hub (18) so as to be slidable in the axial direction. ) External teeth (31a) and a pair of engagement pieces (22a, 22a) for supporting the sleeve gear (19) from both sides in the radial direction. In the vehicle transmission provided with the shifter fork (22) made ,
One of the pair of engagement pieces (22a, 22a) is displaced in the axial direction of the output shaft (13) to support the sleeve gear (19) so as to be inclined with respect to the output shaft (13). And the dog gear (31) and the sleeve gear (19) in contact with each other in a region where a gear-engaging force is generated.

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