JP2010181012A - Planetary carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce weight and manufacturing cost as well as ensuring a desired rigidity. <P>SOLUTION: A planetary gear 20 includes a first sidewall 26a and a second sidewall 26b that are opposed to each other with a given distance placed therebetween along an axial direction of a pinion shaft 16 and a first protruding portion 38a and a second protruding portion 38b that protrude from the first sidewall 26a and the second sidewall 26b, respectively to opposite sides. Then, a welded position 56 created by welding the first and second protruding portions 38a, 38b together is provided between the first sidewall 26a and the second sidewall 26b except basal portions 36a, 36b of the first and second sidewalls 26a, 26b and first and second protrusions 38a, 38b where torsional stresses are concentrated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planetary carrier that supports a pinion shaft.

  Conventionally, for example, planetary gear units including a sun gear, a plurality of pinions, and the like are used in automobile automatic transmissions and the like. The planetary gear unit is provided with a planetary carrier having a pair of side walls that respectively support both end portions of a pinion shaft on which a plurality of pinions are mounted.

  With regard to this type of planetary carrier, for example, in Patent Document 1, a leg portion is extended from one gear support plate (disc) that supports each gear such as a sun gear and a planetary gear, and a tip boss of the leg portion is provided. The coupling strength between the one gear support plate and the other gear support plate can be improved by inserting into the fitting hole of the other gear support plate and welding this fitting portion with an electron beam gun. The technical idea is disclosed.

JP 2002-364740 A

  However, when the technical idea disclosed in Patent Document 1 is applied to, for example, a planetary gear unit having a plurality of pinions in which a plurality of pinions are coaxially mounted on a common pinion shaft, Torsional stress is generated on the planetary carrier that supports the pinion shaft by the reaction force of the meshing. In this case, the torsional stress is concentrated at the connecting portion between the one and other gear support plates and the leg portions constituting the planetary carrier.

  Therefore, in the planetary carrier disclosed in Patent Document 1, in order to maintain the desired rigidity of the planetary carrier, the outer diameter of the leg portion (boss portion) that connects one gear support plate and the other gear support plate. It is necessary to increase the welding area (by increasing the leg portion). As a result, the planetary carrier disclosed in Patent Document 1 has a problem that the weight increases and the manufacturing cost increases.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a planetary carrier capable of ensuring desired rigidity and reducing the weight and manufacturing cost.

  In order to achieve the above object, the present invention includes two side walls facing each other at a predetermined distance, and a connecting portion that connects the two side walls, and supports a pinion shaft between the two side walls. It is a planetary carrier, and each of the two side walls integrally has an extension portion extending from one side wall to the other side wall, and the extension portions are extension portions opposite to each other from the side wall. It welds between the said 2 side walls except the base part which protrudes toward, It comprises the said connection part, It is characterized by the above-mentioned.

  According to the present invention, the torsional stress imparted to the planetary carrier is concentrated, and by providing a welding site where the extension portions are welded between the two side walls excluding the base portion of the side wall and the extension portion, Concentration of torsional stress on the welded portion is preferably avoided, and the desired rigidity of the planetary carrier can be easily ensured.

  As a result, in the present invention, in order to maintain the desired rigidity of the planetary carrier, as in the prior art disclosed in Patent Document 1, the outer portion of the leg portion that connects one gear support plate and the other gear support plate is used. It is not necessary to increase the welding area by increasing the diameter, and it is possible to achieve weight reduction as compared with the prior art and to reduce the manufacturing cost.

  Moreover, in this invention, the welding surface can be increased by making the mating surface where extension parts are welded into an inclined surface or a level | step difference surface, for example, and it improves a welding strength and a planetary carrier. It can contribute to the rigidity of.

  According to the present invention, by providing a welded portion in addition to the base portion of the side wall and the extension portion where the torsional stress is concentrated, it is possible to secure desired rigidity and reduce the weight and manufacturing cost. You can get a career.

It is a disassembled perspective view of the planetary gear unit in which the planetary carrier which concerns on embodiment of this invention was integrated. It is a perspective view of the planetary carrier shown in FIG. It is a front view of the planetary carrier. It is a right view of the said planetary carrier. It is a longitudinal cross-sectional view along the VV line of FIG. It is a skeleton figure which shows the structure of the gear unit which concerns on a comparative example. It is explanatory drawing with which operation | movement description of the gear unit which concerns on a comparative example is provided. It is a side view of the double pinion and carrier which comprise the gear unit concerning a comparative example. It is explanatory drawing which shows the image which the torsional stress was provided to the said planetary carrier, and the connection part deform | transformed. (A) is a front view of the planetary carrier which has the mating surface of the extension part which concerns on a 1st modification, (b) is an exploded perspective view before welding. (A) is a front view of the planetary carrier which has the mating surface of the extension part which concerns on a 2nd modification, (b) is a disassembled perspective view before welding. It is a principal part longitudinal cross-sectional view of the torque distribution mechanism with which the planetary carrier which concerns on other embodiment of this invention was integrated. It is a skeleton figure which shows the structure of the said torque distribution mechanism.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is an exploded perspective view of a planetary gear unit incorporating a planetary carrier according to an embodiment of the present invention.

  As shown in FIG. 1, the planetary gear unit 10 is connected to an input shaft 12a and an output shaft 12b to which a rotational driving force transmitted from a rotational driving source (not shown) is input and output, and to the input shaft 12a and the output shaft 12b, respectively. And two sun gears 14a and 14b that rotate integrally with the input shaft 12a and the output shaft 12b, and tooth portions that mesh with the sun gear 14a on the input shaft 12a side and the sun gear 14b on the output shaft 12b side, respectively. A plurality of twin pinions 18a and 18b formed integrally are pivotally supported so as to be freely rotatable with respect to a common pinion shaft 16, and are arranged at equal angular intervals along the circumferential direction. 20 and so on.

  Further, the planetary gear unit 10 includes a planetary carrier 22 that rotatably supports the pinion shaft 16 and a snap ring 24 that is attached to the end surface of the planetary carrier 22 and prevents the pinion shaft 16 from coming off. The The planetary gear unit 10 includes a ring gear (not shown) that meshes with the double pinion 20 via a tooth portion.

  2 is a perspective view of the planetary carrier shown in FIG. 1, FIG. 3 is a front view of the planetary carrier, FIG. 4 is a right side view of the planetary carrier, and FIG. 5 is taken along line VV in FIG. FIG.

  As shown in FIGS. 2 and 3, the planetary carrier 22 includes a first side wall 26 a and a second side wall 26 b facing each other at a predetermined distance along the axial direction of the pinion shaft 16, and the first side wall. 26a and a connecting portion 28 for connecting the second side wall 26b.

  The first side wall 26a includes a first disc portion 32a having a circular opening 30 through which the input shaft 12a is inserted at the center, and an annular flange projecting outward from the first disc portion 32a. Portion 34 and a base portion 36a continuous to the first disc portion 32a, projecting by a predetermined length from the base portion 36a toward the second side wall 26b, and by an equal angle along the circumferential direction of the first disc portion 32a. There are four first extending portions 38a that are spaced apart from each other, and a circular concave portion 40 that is formed in the first disc portion 32a and is engaged with one end of each pinion shaft 16.

  The second side wall 26b has a first side wall extending from a second disk part 32b in which a circular opening 42 through which the output shaft 12b is inserted is formed at the center, and a root part 36b continuous to the second disk part 32b. 26 a projecting by a predetermined length toward the side 26 a, and four second extending portions 38 b that are spaced apart by an equal angle along the circumferential direction of the second disc portion 32 b, and each pinion formed on the second disc portion 32 b A circular insertion hole 44 through which the other end of the shaft 16 is inserted, four arc-shaped engagement walls 46 for mounting a substantially C-shaped snap ring 24 (see FIG. 1), and the snap ring A locking groove 48 for locking one end of the snap ring 24 to prevent rotation of the snap ring 24 is provided (see FIG. 2).

  The first extension part 38a of the first side wall 26a and the second extension part 38b of the second side wall 26b are provided so as to protrude (extend) toward the extension parts opposite to each other. The mating surface 50 formed on the end surface of the first extending portion 26a and the mating surface 50 formed on the end surface of the second extending portion 26b are welded to form a welded portion 56 (see FIGS. 2 and 3). Thus, the first extending portion 38a and the second extending portion 38b are fixed coaxially to constitute the connecting portion 28.

  The first side wall 26a and the second side wall 26b include a first extending portion 38a and a second extending portion 38b, respectively, and are integrally formed by, for example, forging or casting.

  As shown in FIG. 1, the mating surfaces 50 of the first extension portion 38a and the second extension portion 38b are formed by rectangular flat surfaces that are substantially orthogonal to the input shaft 12a and the output shaft 12b, respectively. In this case, as shown in FIG. 5, the mating surfaces 50 of the first extending portion 38a and the second extending portion 38b are brought into contact with each other, and the mating surfaces 50 are brought together by a welding machine (welding gun 52). By welding and forming the nugget 54, the first and second extending portions 38a and 38b are welded and firmly fixed.

  The planetary gear unit 10 in which the planetary carrier 22 according to the embodiment of the present invention is incorporated is basically configured as described above. Next, its operation and effects are related to the gear unit according to the comparative example. explain.

  6 is a skeleton diagram showing the structure of the gear unit according to the comparative example, FIG. 7 is an explanatory diagram for explaining the operation of the gear unit according to the comparative example, and FIG. 8 is a gear unit according to the comparative example. FIG. 9 is an explanatory view showing an image in which a torsional stress is applied to the carrier and the connecting portion is deformed.

  As shown in FIG. 6, the gear unit 100 according to this comparative example includes a first pinion 104 (corresponding to the sun gear 14 a in FIG. 1) connected to the input shaft 102 that is rotationally driven by a rotational driving force, and an output shaft. 106 (corresponding to the sun gear 14b in FIG. 1) and two pinions 110a and 110b meshing with the first pinion 104 and the second pinion 108, respectively (corresponding to the pinions 18a and 18b in FIG. 1). ) Are opposed to a common pinion shaft 112 (corresponding to the pinion shaft 16 in FIG. 1) and a dual pinion 114 (corresponding to the dual pinion 20 in FIG. 1) arranged coaxially so as to be freely rotatable. Two disc portions 116a and 116b (see FIG. 8) and a plurality of connecting portions 118 that connect the two disc portions 116a and 116b. And a carrier 120 supporting a down 114 (corresponding to the planetary carrier 22 in FIG. 1).

  The operation of the gear unit 100 according to this comparative example will be described briefly. As shown in FIG. 7, the first pinion 104 is rotated along the direction of arrow A by the rotational driving force transmitted to the input shaft 102, and the first One pinion 110a of the double pinion 114 that meshes with the first pinion 104 rotates in the direction of arrow B, and the first pinion 104 and one pinion 110a of the double pinion 114 mesh with each other, thereby preventing the meshing reaction. A force F1 is generated.

  Further, when one pinion 110a of the double pinion 114 rotates, the other pinion 110b connected coaxially through the pinion shaft 112 rotates along the direction of arrow C, and meshes with the other pinion 110b. The second pinion 108 rotates along the direction of arrow D, and the rotational driving force in the direction of arrow D is output from the output shaft 107 connected to the second pinion 108.

  In this case, when the other pinion 110b of the double pinion 114 and the second pinion 108 mesh with each other, a meshing reaction force F2 is generated. The meshing reaction force F1 and the meshing reaction force F2 are generated in opposite directions, and a torsional stress acts on the carrier 120 by the meshing reaction forces F1 and F2 that are directed in opposite directions.

  Therefore, in the carrier 120, the torsional stress is concentrated on the base portion P1 where the one disk portion 116a and the connecting portion 118 are coupled and the root portion P2 where the other disk portion 116b and the connecting portion 118 are connected. As a result, as shown in FIG. 9, the connecting portion 118 that connects one disc portion 116a and the other disc portion 116b is twisted and deformed. In addition, the deformation | transformation state of the connection part 118 shown by FIG. 9 is drawn as an image.

  On the other hand, in this embodiment, the base part 36a of the 1st side wall 26a and the 2nd side wall 26b, the 1st extension part 38a, and the 2nd extension part 38b where the torsional stress provided to the planetary carrier 22 concentrates. , 36b is provided between the first side wall 26a and the second side wall 26b by providing a welded portion 56 (see FIGS. 3 and 5) between the first and second extending portions 38a, 38b. Concentration of torsional stress on 56 is preferably avoided, and the desired rigidity of the planetary carrier 22 can be easily ensured.

  Therefore, in this embodiment, in order to maintain the desired rigidity of the planetary carrier 22, the leg portion that connects one gear support plate and the other gear support plate as in the conventional technique disclosed in Patent Document 1 is used. It becomes unnecessary to increase the outer diameter to increase the welding area, so that weight reduction can be achieved as compared with the prior art, and the manufacturing cost can be reduced.

  In the present embodiment, the first extension portion 38a and the second extension portion 38b along the pinion axis direction have the same (equal length) dimension, and the first side wall 26a and the second side wall that face each other. The torsional stress applied to the planetary carrier 22 is concentrated by providing the welded portion 56 of the first extending portion 26a and the second extending portion 26 at the center between the first extending portion 26b and the second extending portion 26 (see FIGS. 3 and 5). The welded portion 56 can be provided in the portion farthest from the root portions 36a and 36b to be improved, and the rigidity of the planetary carrier 22 can be improved as much as possible.

  In this case, the first extending portion 38a and the second extending portion 38b are not the same in dimensions along the pinion axis direction, and are unequal in length, and are continuous from the first side wall 26a and the second side wall 26b. If the welded part 56 is provided at any part between the first side wall 26a and the second side wall 26b as long as it is other parts excluding the base parts 36a, 36b of the extended part 38a and the second extended part 38b. Good.

  In other words, as shown in the comparative example, the torsional stress applied to the planetary carrier 22 is caused by the base portion 36a and the second side wall 26b and the second extended portion where the first side wall 26a and the first extended portion 38a are connected. Since it concentrates on the base part 36b to which the protrusion part 38b is connected, the first extension part 38a and the second extension part 38b are provided at other parts excluding the base parts 36a and 36b, which are torsional stress concentration parts. By providing the welded part 56, the torsional stress does not concentrate on the welded part 56, and the desired rigidity of the planetary carrier 22 can be easily ensured.

  Further, in the present embodiment, a description is given using a multiple pinion in which a plurality of pinions 18a and 18b are coaxially attached to a common pinion shaft 16 so as to be freely rotatable, but the present invention is not limited to this. However, the present invention can be applied to a single pinion in which a single pinion is pivotally attached to the pinion shaft 16 so as to be freely rotatable.

  Fig.10 (a) is a front view of the planetary carrier which has the mating surface of the extension part which concerns on a 1st modification, FIG.10 (b) is a disassembled perspective view before welding. Fig.11 (a) is a front view of the planetary carrier which has the mating surface of the extension part which concerns on a 2nd modification, FIG.11 (b) is a disassembled perspective view before welding.

  The mating surface 50 to which the extending portions of the first extending portion 38a and the second extending portion 38b are welded is not limited to the rectangular flat surface of FIG. 1, and for example, the first surface of FIG. As shown in the mating surface 50a according to the modification, it is formed by the inclined surface 60 intersecting the pinion axis 16, or as shown in the mating surface 50b according to the second modification in FIG. You may make it form with the level | step difference surface 62 which has this level | step difference. The step surface 62 is not limited to a step shape, and may be any step shape that increases the length of the welded portion 56.

  As described above, the mating surfaces 50a and 50b to which the extending portions of the first extending portion 38a and the second extending portion 38b are welded to each other are the inclined surfaces 60 or the step surfaces 62, whereby the rectangular shape of FIG. Compared with the flat surface, the welding area at the welded portion 56 can be increased (the length of the welded portion 56 can be extended), and the welding strength can be improved to contribute to the rigidity of the planetary carrier 22. it can.

  FIG. 12 is a longitudinal sectional view of an essential part of a torque distribution mechanism incorporating a planetary carrier according to another embodiment of the present invention, and FIG. 13 is a skeleton diagram showing the structure of the torque distribution mechanism.

  A planetary carrier 22a according to another embodiment is different from the above-described embodiment in that three pinions described later use a triple pinion that is rotatably mounted on a common pinion shaft.

  A torque distribution mechanism 200 that distributes driving force between left and right drive wheels of a vehicle (not shown) includes a planetary gear mechanism, and a planetary carrier 22a is rotatably supported with respect to the outer peripheral portion of the output shaft 203 via a bearing 201. In addition, three pinions including the first pinion 204a, the second pinion 204b, and the third pinion 204c are integrally formed on each of the four pinion shafts 202 arranged at a separation angle of 90 degrees along the circumferential direction. The formed triple pinion 206 is rotatably supported.

  A first sun gear 208a meshing with the first pinion 204a is rotatably fixed to the outer periphery of the drive shaft S connected to the left and right drive wheels via a drive shaft (not shown). The second sun gear 208b fixed to the outer periphery of the drive shaft S is provided so as to mesh with the second pinion 204b. Further, a third sun gear 208c rotatably supported on the outer periphery of the output shaft 203 is provided so as to mesh with the third pinion 204c.

  In this case, the third sun gear 208c is provided so as to be connectable to the housing 210 of the torque distribution mechanism 200 via the right clutch CR, and the rotational speed of the planetary carrier 22a is increased by the engagement of the right clutch CR. The planetary carrier 22a is provided so as to be connectable to the housing 210 via the left clutch CL, and the rotational speed of the planetary carrier 22a is reduced by the engagement of the left clutch CL.

  The rotational driving force driven by the engine (not shown) is transmitted along the direction of the arrow, and the first sun gear 208a, the first pinion 204a, the pinion shaft 202, the second pinion 204b, and the second pinion are engaged with each other from the output shaft 203. 2 is transmitted to the drive shaft S via the sun gear 208b.

  The other configurations and operational effects of the planetary carrier 22a according to another embodiment are the same as those of the planetary carrier 22 shown in FIG.

16, 202 Pinion shaft 18a, 18b, 204a to 204c Pinion 22, 22a Planetary carrier 26a, 26b Side wall 28 Connection portion 36a, 36b Base portion 38a, 38b Extension portion 50, 50a, 50b Mating surface 56 Welded portion 60 Inclined surface 62 Step surface

Claims (2)

A planetary carrier comprising two side walls facing each other at a predetermined distance and a connecting portion for connecting the two side walls, and supporting a pinion shaft between the two side walls,
Each of the two side walls integrally has an extension portion extending from one side wall to the other side wall, and the extension portions protrude from the side walls toward the opposite extension portions. A planetary carrier characterized in that it is welded between the two side walls excluding a portion to constitute the connecting portion. The planetary carrier according to claim 1,
The planetary carrier characterized in that the mating surface to which the extending portions are welded includes at least an inclined surface intersecting the pinion axis or a step surface having a step.

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