JP6629162B2 - Power transmission mechanism - Google Patents

Description

  The present invention relates to a power transmission mechanism including a gear, a friction engagement element, and the like, and particularly to a power transmission mechanism suitable for a transmission mounted on a vehicle.

  For example, continuously variable transmissions (CVT: Continuously Variable Transmission) and stepped automatic transmissions (AT: Automatic Transmission) are widely known as automatic transmissions mounted on vehicles.

  In an automatic transmission, a plurality of gears are used to transmit power. For example, in the configuration shown in FIG. 4, a first gear 403 and a second gear 404 are used to transmit power from an input shaft (not shown) to the carrier 402 of the planetary gear mechanism 401. The first gear 403 is provided so as to be able to rotate integrally with the input shaft. The second gear 404 is supported by the output shaft 406 via a bearing 405 so as to be relatively rotatable.

  The carrier 402 is provided so as to be integrally rotatable with a brake hub 408 of a brake 407 that brakes / allows rotation of the carrier 402. Specifically, the brake hub 408 includes a base end 411 extending outward from the second gear 404 in the radial direction of rotation, and an extension 412 extending from the base end 411 in the rotational axis direction. The base end 411 of the brake hub 408 is fixed to the second gear 404 by welding. The carrier 402 is spline-fitted to the extending portion 412, and extends inward in the rotational radial direction from the spline-fitted portion.

  With this configuration, when power is transmitted from the first gear 403 to the second gear 404 with the brake 407 released, the carrier 402 and the brake hub 408 rotate integrally with the second gear 404.

JP-A-2015-145682

  The second gear 404 is fitted around the outer ring of the bearing 405 with play. Therefore, the input of power (torque) from the first gear 403 to the second gear 404 causes the second gear 404 to be displaced within a play range, and the rotation of the second gear 404 causes the base end of the brake hub 408 to rotate. Compressive stress and tensile stress are alternately generated in the welded portion between the portion 411 and the second gear 404, and there is a possibility that the welded portion may be damaged such as a crack.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power transmission mechanism in which a plate-shaped member is fixed by welding to a second gear to which power is transmitted from a first gear, which can suppress occurrence of breakage such as a crack in a welded portion. It is to be.

  In order to achieve the above object, a power transmission mechanism according to the present invention includes a first gear, a second gear meshed with the first gear, and power transmitted from the first gear, and a base end connected to the second gear. And a plate-shaped member that is fixed by welding and extends outward from the base end in the rotational radial direction of the second gear. The plate-shaped member is formed with a plurality of holes for reducing the rigidity of the plate-shaped member. ing.

  According to this configuration, power is transmitted from the first gear to the second gear that meshes with the first gear. The base end of a plate-like member extending in the rotation radial direction of the second gear is fixed to the second gear by welding. And a plurality of holes for reducing the rigidity are formed in the plate-shaped member. Accordingly, when power is input from the first gear to the second gear and the second gear is displaced within the range of the play, the stress generated in the welded portion between the base end of the plate member and the second gear Can be reduced. Therefore, it is possible to suppress the occurrence of breakage such as a crack due to stress in the welded portion.

  Further, since a plurality of holes are formed in the plate member, the weight of the plate member is reduced. As a result, the power transmission mechanism is reduced in weight, so that, for example, when the power transmission mechanism is used for an automatic transmission of a vehicle, the vehicle equipped with the automatic transmission can have low fuel consumption.

  The plate-shaped member may be formed such that a portion extending outward from the base end in the rotational radial direction with respect to the base end is thin.

  Thereby, the rigidity of the plate-shaped member can be further reduced, and the occurrence of breakage in the welded portion between the base end of the plate-shaped member and the second gear can be further suppressed. Further, the weight of the plate member can be further reduced, and the effect of the weight reduction of the plate member can be increased.

  The hole may be a long hole extending in the rotation direction of the second gear.

  By forming a plurality of long holes in the plate member, rigidity can be reduced as compared with a configuration in which a plurality of round holes are formed in the plate member.

  The slots may be formed in a plurality of rows in the rotation radial direction of the second gear, and in that case, it is preferable that the positions of the slots in the rotation direction in the rows adjacent to each other are shifted.

  Thereby, the rigidity of the plate-shaped member can be further reduced, and the occurrence of breakage in the welded portion between the base end of the plate-shaped member and the second gear can be more effectively suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the stress which generate | occur | produces in the welding part of the base end part of a plate-shaped member and a 2nd gear can be reduced, and it can suppress that damage, such as a crack by stress, arises in the welding part.

1 is a cross-sectional view illustrating a part of a transmission that employs a drive transmission mechanism according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view showing a driven gear and a brake hub shown in FIG. 1. It is the figure which looked at the brake hub from the left, and shows a part of brake hub. FIG. 9 is a cross-sectional view illustrating a configuration of a conventional drive transmission mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Transmission>
FIG. 1 is a sectional view showing a part of a transmission 1 in which a drive transmission mechanism according to one embodiment of the present invention is employed. In FIG. 1, hatching representing a cross section is omitted. In addition, in each cross-sectional view including FIG. 1, only the configuration on one side of the rotation axis is shown.

  FIG. 1 shows a part of a transmission 1 mounted on a vehicle. Specifically, the transmission 1 has a configuration of a continuously variable transmission (not shown) in which a belt is wound around a primary pulley and a secondary pulley, and FIG. The configuration of the connection portion between the output shaft 2 and the output shaft 3 is shown. The secondary shaft 2 and the output shaft 3 are arranged coaxially and rotatably provided.

  In the following description, the side of the output shaft 3 with respect to the secondary shaft 2 is referred to as “right side”, and the side of the secondary shaft 2 with respect to the output shaft 3 is referred to as “left side”.

  The transmission 1 is provided with a planetary gear mechanism 11 for transmitting power between the secondary shaft 2 and the output shaft 3. The planetary gear mechanism 11 includes a sun gear 12, a carrier 13, a ring gear 14, and a plurality of pinion gears 15.

  Further, the transmission 1 is provided with a parallel shaft type gear mechanism 21 for transmitting power input to an input shaft (not shown) to the planetary gear mechanism 11 without passing through a belt. The parallel shaft type gear mechanism 21 includes a drive gear 22 held on an input shaft, and a driven gear 23 that meshes with the drive gear 22.

  The driven gear 23 is rotatably held on the output shaft 3 via a bearing 24. The driven gear 23 is fixed to the outer ring 26 of the bearing 24 in the rotation axis direction by a snap ring 25. Specifically, a first groove 27 extending in the circumferential direction is formed on the outer peripheral surface of the outer ring 26 of the bearing 24 over the entire circumference. On the other hand, on the inner peripheral surface of the driven gear 23, a second groove 28 extending in the circumferential direction is formed over the entire circumference at a position facing the first groove 27 in the rotational radial direction. The driven gear 23 is fixed to the outer ring 26 of the bearing 24 in the rotation axis direction by fitting the snap ring 25 across both the first groove 27 and the second groove 28.

  The sun gear 12 of the planetary gear mechanism 11 is fitted around the right end of the secondary shaft 2 and spline-coupled to the secondary shaft 2.

  The carrier 13 is provided so as to be integrally rotatable with a brake hub 31 of a brake B1 that brakes / allows rotation of the carrier 13. Specifically, the brake hub 31 includes a substantially annular plate-shaped portion 32 extending outward from the driven gear 23 in the radial direction of rotation, and a substantially cylindrical extension portion extending leftward from the outer peripheral end of the plate portion 32. 33 are integrally provided. A base end (inner peripheral end) 34 of the plate portion 32 of the brake hub 31 is fixed to the driven gear 23. The carrier 13 is spline-coupled to the extending portion 33, and extends inward in the rotational radial direction from the spline-coupled portion.

  The plurality of pinion gears 15 are rotatably held by the carrier 13. Each pinion gear 15 meshes with the sun gear 12.

  The ring gear 14 has a substantially cylindrical shape that encloses the plurality of pinion gears 15 collectively, and is held so as to be relatively non-rotatable by the clutch drum 41 of the clutch C1 that directly connects / disconnects the sun gear 12 and the ring gear 14. The clutch drum 41 is fixed to the output shaft 3 on the left side of the bearing 24, and extends from the output shaft 3 to the left side of the plate portion 32 of the brake hub 31 outward in the radial direction of rotation. And a substantially cylindrical extending portion 43 extending leftward from the outer peripheral end of the plate-like portion 42 inside the extending portion 33 of the brake hub 31 in the rotational radial direction. The ring gear 14 is held by the extension portion 43 by spline coupling, and meshes with each of the pinion gears 15 from the outside in the rotation radial direction.

  With this configuration, when power is transmitted from the drive gear 22 to the driven gear 23 in a state where the brake B1 and the clutch C1 are released, the carrier 13 and the brake hub 31 rotate integrally with the driven gear 23. In a state where the brake B1 is released and the clutch C1 is engaged, the sun gear 12, the carrier 13, and the ring gear 14 rotate integrally, and the secondary shaft 2 and the output shaft 3 rotate at the same speed. At this time, transmission of power from the input shaft to the drive gear 22 is interrupted, and power is not transmitted from the drive gear 22 to the driven gear 23.

<Brake hub>
FIG. 2 is an enlarged sectional view showing the driven gear 23 and the brake hub 31 shown in FIG. In FIG. 2, hatching representing a cross section is omitted.

  The base end 34 of the plate portion 32 of the brake hub 31 is fixed to the left end of the driven gear 23 by welding. Specifically, a groove 51 having a substantially square cross section is formed at the left end of the driven gear 23 over the entire circumference. The groove 51 is open on the outer peripheral surface and the left end surface of the driven gear 23. The base end portion 34 is formed to have a thickness substantially equal to the width of the groove 51 in the left-right direction (the rotation axis direction of the driven gear 23). The base end portion 34 is fitted into the groove 51 from the left side, and a contact portion between the inner peripheral surface and the peripheral surface facing the groove 51 of the driven gear 23 is welded.

  A portion other than the base end portion 34 of the plate portion 32 of the brake hub 31, in other words, a portion 52 of the plate portion 32 extending outward in the rotational radial direction from the base end portion 34 is formed to be thinner than the base end portion 34. The right end surface of the thin portion 52 is shifted one step to the left with respect to the right end surface of the base end portion 34.

  FIG. 3 is a view of the brake hub 31 as viewed from the left side, and shows a part of the brake hub 31.

  A plurality of holes 53 are formed in the thin portion 52 of the plate portion 32 of the brake hub 31. Each hole 53 is a long hole extending in the rotation direction (the circumferential direction of the brake hub 31). The plurality of holes 53 form three rows in the rotation radial direction, and are formed at intervals in the rotation direction in each row. ing. Further, the plurality of holes 53 are formed so as to be shifted from each other in the rotation direction in rows adjacent to each other.

<Effects>
According to this configuration, power is transmitted from the drive gear 22 to the driven gear 23 that meshes with the drive gear 22. The base end 34 of the plate-shaped portion 32 of the brake hub 31 extending in the rotation radial direction of the driven gear 23 is fixed to the driven gear 23 by welding. A plurality of holes 53 are formed in the plate portion 32 of the brake hub 31 to reduce its rigidity. As a result, when power is input from the drive gear 22 to the driven gear 23 and the driven gear 23 is displaced within a play range between the driven gear 23 and the outer ring 26 of the bearing 24, the base end of the plate-shaped portion 32 of the brake hub 31. The stress generated in the welded portion 54 between the portion 34 and the driven gear 23 can be reduced. Therefore, it is possible to suppress the occurrence of breakage such as a crack due to stress in the welded portion 54.

  Further, since the plurality of holes 53 are formed in the plate portion 32 of the brake hub 31, the weight of the plate portion 32 of the brake hub 31 is reduced. As a result, the weight of the transmission 1 is reduced, so that the vehicle on which the transmission 1 is mounted can have low fuel consumption.

  The plate portion 32 of the brake hub 31 has a thin portion 52 that extends outward from the base end portion 34 in the rotational radial direction with respect to the base end portion 34. Thereby, the rigidity of the plate portion 32 of the brake hub 31 can be further reduced, and the occurrence of breakage in the welded portion 54 between the base end portion 34 of the plate portion 32 of the brake hub 31 and the driven gear 23 is further suppressed. it can. Further, the weight of the plate portion 32 of the brake hub 31 can be further reduced, and the effect of the weight reduction of the plate portion 32 of the brake hub 31 can be increased.

  The hole 53 is formed as a long hole extending in the rotation direction (circumferential direction) of the driven gear 23. Thereby, the rigidity can be reduced as compared with a configuration in which a plurality of round holes are formed in the plate-shaped portion 32 of the brake hub 31.

  The holes 53 are formed so as to form three rows in the rotational radial direction, and are formed so that the positions in the rotational direction are shifted in adjacent rows. Thereby, the rigidity of the plate portion 32 of the brake hub 31 can be further reduced, and the occurrence of breakage in the welded portion between the base end portion 34 of the plate portion 32 of the brake hub 31 and the driven gear 23 can be more effectively reduced. Can be suppressed.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented in another form.

  For example, in the above-described embodiment, the holes 53 are formed in three rows in the rotational diameter direction. However, the holes 53 may be formed in two rows in the rotational diameter direction. It may be formed in rows or more.

  Further, the transmission 1 has a configuration of a continuously variable transmission, but is not limited to a continuously variable transmission, and may be a transmission having a configuration of a stepped automatic transmission (AT: Automatic Transmission) or a manual transmission. The present invention can be widely applied to various types of transmissions such as a transmission (MT: Manual Transmission). Further, the present invention can be applied to a mechanism other than the transmission.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

22: drive gear (first gear)
23: Driven gear (second gear)
32: plate-shaped part (plate-shaped member)
53: Hole

Claims (1)

A first gear;
A second gear meshed with the first gear, and power is transmitted from the first gear;
A base member fixed to the second gear by welding, and a plate-shaped member extending outward from the base end in the rotation radial direction of the second gear;
The second gear has a play around a cylindrical surface about the rotation axis of the second gear,
The second gear has a groove formed on one end surface and an outer peripheral surface of the second gear,
The base end of the plate-shaped member is formed to have the same thickness as the width of the groove in the rotation axis direction, and is welded to a surface of the groove facing the rotation radial direction, and the groove is rotated from the groove. Extend radially,
A power transmission mechanism, wherein a plurality of holes for reducing rigidity of the plate member are formed in the plate member.

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