JP2019100409A - Power transmission mechanism - Google Patents

Abstract

To suppress moment in a radial direction occurring on a rotational shaft having a plurality of herringbone gears.SOLUTION: A power transmission mechanism comprises: a first shaft with a first herringbone gear; a second shaft having a second herringbone gear engaged to the first herringbone gear, and a third herringbone gear arranged in parallel with the second herringbone gear in an axis direction; and a third shaft having a fourth herringbone gear engaged to the third herringbone gear. On the second shaft, one of the second herringbone gear and the third herringbone gear is formed by a pair of helical gears, wherein the pair of helical gears are arranged symmetrically to the axis direction so as to hold the other helical gear.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission mechanism.

  Patent Document 1 discloses, as a power transmission mechanism mounted on a vehicle, a power transmission mechanism in which a final gear pair in which a final drive gear and a final driven gear (a differential ring gear) mesh with each other is a gear pair in which a helical gear meshes with each other. ing.

JP, 2016-56888, A

  In a power transmission mechanism of a three-axis structure provided with a double-helical gear, a plurality of double-helical gears are provided on one rotation shaft as an intermediate shaft. For example, as in the power transmission mechanism 100 shown in FIG. 4, two helical gears 101 and 102 are arranged axially in line in the second axis. Then, at the time of power transmission, as shown in FIG. 5, separation forces F1 and F2 are generated in the radial direction at the meshing portions of the helical gears. In this case, since the meshing points on the two shafts are different at the meshing point, the separation force F1 generated by the meshing of the mountain gear 101 generates a moment M1, and the torque M2 generated by the meshing of the mountain gear 102 M2 occurs (see FIGS. 4 and 5). As described above, when a moment in the radial direction is generated on the rotary shaft having a plurality of helical gears during power transmission, the loss of the bearing that supports the rotary shaft increases, and the meshing portion may come into contact with one tooth. There is.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a power transmission mechanism capable of suppressing a moment in a radial direction generated on a rotating shaft having a plurality of helical gears.

  The present invention comprises a first shaft having a first sheave gear, a second sheave gear meshing with the first sheave gear, and a third sheave gear axially aligned with the second sheave gear. In a power transmission mechanism including a second shaft having a second shaft and a third shaft having a fourth gear engaged with the third gear, on the second shaft, the second gear and the third gear and One of the above is characterized by being constituted by a pair of helical gears disposed at axially symmetrical positions so as to sandwich the other helical gear.

  In the present invention, on the second shaft having a plurality of helical gears, a pair of helical gears constituting one helical gear is disposed at an axially symmetrical position with respect to the other helical gear. There is. Thereby, it is possible to suppress the occurrence of a moment in the radial direction on the second axis.

FIG. 1 is a view schematically showing a power transmission mechanism of the embodiment. FIG. 2 is a diagram for explaining the position of axial symmetry. FIG. 3 is a view schematically showing a modified example of the power transmission mechanism. FIG. 4 is a view schematically showing an example of the conventional structure. FIG. 5 is a diagram for explaining the separation force generated in the conventional structure.

  The power transmission mechanism in the embodiment of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a view schematically showing a power transmission mechanism 1 of the embodiment. The power transmission mechanism 1 is configured in a three-axis structure including a first shaft 10, a second shaft 20, and a third shaft 30 as three rotation axes arranged in parallel to one another. The first shaft 10 and the third shaft 30 are rotation shafts (one gear shaft meshing with a single spiral gear provided on another shaft) having one spiral gear. On the other hand, the second shaft 20, which is an intermediate shaft, is a rotating shaft having a plurality of helical gears (a gear shaft engaged with a plurality of helical gears provided on another shaft). The power transmission mechanism 1 has a structure in which a plurality of gears are arranged at symmetrical positions in the axial direction, and one of the plurality of spiral gears provided on the second shaft 20 is a spiral gear. It is configured in a separated structure.

  Specifically, the power transmission mechanism 1 includes a first shaft 10 having a first helical gear 11, a second shaft 20 having a second helical gear 21 meshing with the first helical gear 11, and a second shaft 20. And a third shaft 30 having a fourth spiral gear 31 meshing with the third spiral gear 22. The third shaft gear 22 is provided on the upper side in the axial direction with the second spiral gear 21. The first shaft 10 and the second shaft 20 are coupled so as to be able to transmit power by a gear pair configured by the first double gear 11 and the second double gear 21. The second shaft 20 and the third shaft 30 are coupled so as to be able to transmit power by a gear pair configured by the third helical gear 22 and the fourth helical gear 31. Then, the power of the first shaft 10 is transmitted to the third shaft 30 via the second shaft 20. In this description, with regard to the arrangement in the axial direction, one side in the axial direction is described as the left side, and the other side in the axial direction is described as the right side.

  The first spiral gear 11 is a gear that rotates integrally with the first shaft 10, and is configured by a pair of helical gears including a left gear 11a and a right gear 11b whose twist directions are opposite to each other. Further, the first pinion gear 11 is integrated so as not to be movable relative to the first shaft 10 in the axial direction.

  The second double gear 21 is a first double gear disposed on the second shaft 20 and meshes with the first double gear 11. The second ring gear 21 is a gear integrally rotating with the second shaft 20, and is constituted by a pair of helical gears including a left gear 21a and a right gear 21b whose twist directions are opposite to each other. Further, the second ring gear 21 is integrated so as not to be movable relative to the second shaft 20 in the axial direction.

  At the meshing portion between the first double gear 11 and the second double gear 21, the left gears 11 a and 21 a mesh with each other, and the right gears 11 b and 21 b mesh with each other.

  The third ring gear 22 is a second ring gear disposed on the second shaft 20, and is a gear having a separated structure. The third ring gear 22 is constituted by a pair of helical gears (left gear 22 a and right gear 22 b) disposed at positions axially symmetrical with respect to the second ring gear 21. The left gear 22a and the right gear 22b are a pair of helical gears whose twisting directions are opposite to each other, and are disposed at symmetrical positions in the axial direction about the axially central portion of the second pinion gear 21. Ru. The left gear 22 a is disposed axially to the left of the second helical gear 21, and the right gear 22 b is disposed axially to the right of the second helical gear 21. As shown in FIG. 1, on the second shaft 20, from left to right in the axial direction, the left gear 22a of the third gear 22 and the left gear 21a of the second gear 21, the second gear The right gear 21 b of the gear 21 and the right gear 22 b of the third double gear 22 are arranged in this order. Further, the third gear wheel 22 is integrated so as not to be relatively movable in the axial direction with respect to the second shaft 20, and rotates integrally with the second shaft 20. Furthermore, the third double gear 22 is a gear having a smaller diameter than the second double gear 21. The left gear 22a and the right gear 22b have the same diameter.

  The fourth ring gear 31 is a ring gear meshing with the third ring gear 22 and is a separated gear. The fourth ring gear 31 is disposed at a position axially symmetrical with respect to an axial position (broken line shown in FIG. 2) based on the axial center of the second ring gear 21 on the second shaft 20. It comprises the left gear 31a and the right gear 31b. The left gear 31a and the right gear 31b are a pair of helical gears whose twist directions are opposite to each other, and both are formed to have the same diameter.

  The left gears 22a and 31a mesh with each other and the right gears 22b and 31b mesh with each other at the meshing portion between the third gear 22 and the fourth gear 31. The axial position of the meshing portion of the power transmission mechanism 1 is the meshing portion between the left gear 22 a of the third gear 22 and the left gear 31 a of the fourth gear 31 from the axial left side toward the right, The meshing portion between the left gear 11a of the first double gear 11 and the left gear 21a of the second double gear 21, the right gear 11b of the first double gear 11 and the right gear 21b of the second double gear 21 The meshing portion and the meshing portion between the right gear 22b of the third gear wheel 22 and the right gear 31b of the fourth gear wheel 31 are axially symmetrical (see FIG. 2).

  Further, in the example shown in FIG. 1, the fourth ring gear 31 is a differential ring gear, and a differential mechanism 32 is provided on the third shaft 30. The power transmission mechanism 1 is mounted on a vehicle, and a final gear pair is constituted by a helical gear. Therefore, the left gear 31a is a first differential ring gear that rotates integrally with the differential case 32a, and the right gear 31b is a second differential ring gear that rotates integrally with the differential case 32a. The third shaft 30 is a left and right axle. As the entire configuration of the power transmission mechanism 1, the first shaft 10 is an input shaft, the first gear 11 is an output gear, the second shaft 20 is a counter shaft, the second gear 21 is a counter driven gear, and the third gear The double gear 22 is a counter drive gear (drive pinion gear) engaged with the differential ring gear, and the double gear pair consisting of the third double gear 22 and the fourth double gear 31 is a final gear pair, and the fourth double gear 31 is a differential case 32a. The diff ring gear is integrated with the As described above, part of the differential mechanism 32 can be configured by the third shaft 30 and the fourth helical gear 31.

  As described above, in the power transmission mechanism 1 of the embodiment, the left and right gears 22a and 22b of the third helical gear 22 are axially symmetrical on the second shaft 20 so as to sandwich the second helical gear 21. Be placed. Thereby, it is possible to suppress the occurrence of a moment in the radial direction on the second shaft 20. As a result, it is possible to reduce the loss of the bearing that supports the second shaft 20 and to suppress the occurrence of a single tooth contact at the meshing portion of the helical gear pair. In addition, by forming the third helical gear 22 in a separated structure, it becomes easy to machine the tooth flank etc., and it is possible to shorten the machining time of the gear and to reduce the machining cost.

  The power transmission mechanism 1 is not limited to the configuration shown in FIG. 1 described above, but a pair of helical gears (left gear 21a and right gear 21b) constituting the second spiral gear 21 is configured in a separated structure It is also good. In short, the power transmission mechanism 1 is disposed at an axially symmetrical position so that one of the second helical gear 21 and the third helical gear 22 on the second shaft 20 sandwiches the other helical gear. What is necessary is just to be comprised by a pair of helical gears. Therefore, as a modification, a power transmission mechanism 1 in which the second double gear 21 is configured as a separated structure is shown in FIG.

  As shown in FIG. 3, in the modification, the second double gear 21 is a separate gear, and the left and right gears 21 a and 21 b are disposed at axially symmetrical positions so as to sandwich the third double gear 22. . In this case, the first pinion gear 11 is also configured as a separated structure, and the left gear 11a and the right gear 11b are arranged at positions separated in the axial direction. The third double gear 22 is disposed such that the left gear 22a and the right gear 22b are axially adjacent to each other. Similarly, in the fourth ring gear 31 which is a differential ring gear, the left gear 31 a and the right gear 31 b are disposed adjacent to each other in the axial direction. Then, as shown in FIG. 3, on the second shaft 20, the left gear 21a of the second spiral gear 21 and the left gear 22a of the third spiral gear 22 are directed from the left side to the right side in the axial direction. The right gear 22 b of the double-helical gear 22 and the right gear 21 b of the second double-helical gear 21 are arranged in this order.

  In addition, this invention is not limited to embodiment mentioned above, It can change suitably in the range which does not deviate from the objective of this invention. For example, the power transmission mechanism 1 may have a three-shaft structure, and is not necessarily limited to one including the differential mechanism 32 and having the final gear pair configured by a helical gear pair. As an example, when the power transmission mechanism 1 is mounted on a vehicle, the invention can also be applied to an electric vehicle using a motor as a driving power source. In this case, the first shaft 10 is an input shaft that rotates integrally with the rotor shaft of the motor, and the power transmission mechanism 1 can be configured with the second shaft 20 as a counter shaft and the third shaft 30 as a differential case. The first shaft 10 may be a rotating shaft that rotates integrally with the traveling power source, or may be a rotating shaft that rotates integrally with the output shaft of the transmission.

DESCRIPTION OF SYMBOLS 1 power transmission mechanism 10 1st axis 11 1st latitudinal gear 11a left gear 11b right gear 20 2nd axis 21 2nd latitudinal gear 21a left gear 21b right gear 22 22nd 3rd spiral gear 22a left gear 22b right gear 30 1st gear 3 axis 31 4th ring gear 31a left gear 31b right gear

Claims (1)

A first shaft having a first helical gear;
A second shaft gear meshing with the first gear wheel, and a second shaft having a third gear wheel axially arranged in line with the second gear wheel;
And a third shaft having a fourth helical gear meshing with the third helical gear.
On the second axis, a pair of helical gears disposed at axially symmetrical positions so that one of the second helical gear and the third helical gear sandwiches the other helical gear. A power transmission mechanism characterized by:

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