JP2010025176A - Lubricating structure of planetary gear mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain abrasion or seizure of a planetary shaft 62 and a bearing 63 of a planetary gear 38 and a carrier 37 in a planetary gear mechanism 31. <P>SOLUTION: A suction groove 65 for introducing working fluid to a supporting hole 61 to which the planetary shaft 62 and the bearing 63 are fitted are formed on one side surface of the planetary gear 38 so as to extend from the supporting hole 61 to the radial outer side and to be tilted to the rotation direction downstream side of the planetary gear 38. Further, a delivery groove 66 for delivering the working fluid from the supporting 61 is formed on the other side surface of the planetary gear 38 so as to extend from the supporting hole 61 to the radial outer side and to be tilted to the rotation direction upstream side of the planetary gear 38. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lubrication structure for a planetary gear mechanism provided in a transmission of a vehicle, for example.

  Conventionally, a planetary gear mechanism disposed in a transmission for a vehicle includes a plurality of planetary gears, a carrier that rotatably supports these planetary gear groups, and a sun gear that meshes with all the planetary gears from the inside. And a ring gear meshing from the outside. Each planetary gear is rotatably fitted on a planetary shaft attached to the carrier via a bearing. This type of planetary gear mechanism is configured to smoothly increase and decrease the rotational power transmitted from the engine by the interlocking relationship of the sun gear, the carrier, the planetary gear group, and the ring gear.

When the vehicle is driven, each planetary gear rotates at a high speed, particularly in the planetary gear mechanism. The frictional heat generated due to such high-speed rotation causes seizure of the bearing or the like. In this regard, in Patent Document 1, a circulation hole is formed by drilling the shaft center of the planetary shaft, and an opening hole communicating from the circulation hole to the outer peripheral surface of the planetary shaft is formed. It has been disclosed to lubricate bearings and the like by discharging hydraulic oil from an opening hole through a hole by centrifugal force.
Japanese Patent Laying-Open No. 2005-106232 (see, for example, FIG. 4)

  However, in the configuration of Patent Document 1, since the hole diameters of the flow holes and the opening holes are very small, it takes time to manufacture, and it is difficult to say that the flow of hydraulic oil and the lubricity are sufficient, and there is room for improvement. was there. This invention makes it a technical subject to improve such a present condition.

  A lubricating structure of a planetary gear mechanism according to the invention of claim 1 includes a carrier, a planetary shaft attached to the carrier, a planetary gear rotatably supported on the planetary shaft via a bearing, and the planetary gear. In a planetary gear mechanism including a washer fitted on the planetary shaft in a state of being interposed between the carrier and the carrier, hydraulic oil is inserted into a support hole in which the planetary shaft and the bearing are fitted on one side surface of the planetary gear. Is formed so as to extend radially outward from the support hole and to incline toward the downstream side in the rotational direction of the planetary gear.

  According to a second aspect of the present invention, in the lubricating structure of the planetary gear mechanism according to the first aspect, a discharge groove for discharging hydraulic oil from the support hole is provided on the other side surface of the planetary gear from the support hole. It is formed so as to extend radially outward and incline toward the upstream side in the rotation direction of the planetary gear.

  According to the first aspect of the present invention, the suction groove for introducing the hydraulic oil into the support hole into which the planetary shaft and the bearing are fitted is formed on one side surface of the planetary gear so as to extend radially outward from the support hole. Since it is formed so as to incline toward the downstream side in the rotation direction, when hydraulic oil applied to one side surface of the planetary gear enters the suction groove, the hydraulic oil in the suction groove is As the gear rotates, it is pushed radially inward (to the support hole) by the peripheral wall of the suction groove.

  For this reason, the hydraulic oil in the suction groove forcibly flows into the support hole, the planetary gear, the bearing and the planetary shaft are lubricated, and heat generation due to these frictions is suppressed. Therefore, it is possible to suppress the wear and seizure of the planetary gear, the bearing, and the planetary shaft, thereby improving the durability (prolonging the life).

  According to the invention of claim 2, a discharge groove for discharging hydraulic oil from the support hole extends radially outward from the support hole on the other side surface of the planetary gear and is upstream of the rotation direction of the planetary gear. Since it is formed so as to incline toward the side, the hydraulic oil that has flowed into the support hole is pushed outward in the radial direction by the centrifugal force accompanying the rotation of the planetary gear, and flows into the discharge groove. The hydraulic oil in the discharge groove is pushed outward in the radius by the peripheral wall of the discharge groove and centrifugal force as the planetary gear rotates, and is discharged to the outside of the planetary gear.

  Therefore, there is an effect that the fluidity of the working oil in the support hole in the planetary gear, and hence the lubricity of the planetary gear, the bearing, and the planetary shaft can be further improved.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings (FIGS. 1 to 6) when applied to a planetary gear mechanism in a transmission for a farm tractor.

  First, an outline of a tractor will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, a tractor traveling body 1 is supported by front and rear four wheels 2, 2, 3, 3 serving as traveling portions disposed on the left and right sides of the tractor.

  An engine 4 as a power source and a steering column 5 having a steering handle 6 are provided on the upper front portion of the traveling machine body 1. A driver seat 7 is disposed behind the steering handle 6. When the operator sitting on the driver's seat 7 rotates the steering handle 6, the steering angle (steering angle) of the left and right front wheels 2 and 2 changes according to the operation amount (rotation amount). Has been.

  A transmission case 8 having a hydraulic / mechanical (HMT type) transmission 9 for appropriately shifting the power from the engine 4 and transmitting it to the front and rear four wheels 2, 2, 3, 3 is provided at the rear of the traveling machine body 1. It is installed. A link mechanism 10 to which a scraper, a rake, a tiller, etc. (not shown) can be attached is provided at the rear end of the traveling machine body 1.

  Next, the power transmission system of the tractor will be described with reference to FIGS.

  The tractor according to this embodiment transmits power transmitted from the engine 4 to the hydraulic / mechanical transmission 9 in the transmission case 8 via the front wheel final reduction gear 12 (see FIG. 1) with a differential limiting mechanism. In addition to outputting to the front wheels 2, 2, it is configured to output to the left and right rear wheels 3, 3 via a rear wheel final reduction device 13 with a differential limiting mechanism.

  An output shaft 17 from the engine 4 protrudes in a gear case 16 attached to the rear surface of the engine 4. A drive shaft 18 that protrudes rearward from the rear surface of the gear case 16 is attached to the lower portion of the gear case 16 in parallel with the output shaft 17. The working hydraulic pump 19 provided on the rear surface of the gear case 16 is concentrically connected to the output shaft 17.

  In the gear case 16, the output gear 21 fixed to the output shaft 17 meshes with the idler gear 22. The idler gear 22 meshes with a drive gear 23 fixed to the drive shaft 18. The number of teeth of the output gear 21, the idler gear 22, and the drive gear 23 is set so that power is transmitted from the output shaft 17 to the drive shaft 18 at the same rotational speed. The power transmitted to the drive shaft 18 is transmitted to the input shaft 25 protruding forward from the front surface of the transmission case 8 via the transmission shaft 24 having universal joints at both front and rear ends.

  The hydraulic / mechanical (HMT type) transmission 9 provided in the mission case 8 includes a planetary gear mechanism 31 and a hydrostatic (HST type) transmission mechanism 32 including a hydraulic pump 33 and a hydraulic motor 34. Yes.

  The hydraulic / mechanical transmission 9 according to this embodiment transmits power transmitted to the input shaft 25 to a sun gear shaft 35 (details will be described later) of the planetary gear mechanism 31 and an input pump shaft 53 (details are described later). And the power transmitted via the output motor shaft 54 (details will be described later) from the hydraulic motor 34, and the front and rear four wheels 2, 2, 3 and 3 are rotationally driven. That is, the hydraulic / mechanical transmission 9 is of an input division type.

  The sun gear shaft 35 of the planetary gear mechanism 31 is pivotally supported in a position above the input shaft 25 in the mission case 8 so as to be parallel to the input shaft 25 and rotatable via a bearing in the mission case 8. ing. A gear 26 fixed to the input shaft 25 meshes with a transmission gear 36 loosely fitted to the front end portion of the sun gear shaft 35 via a bearing.

  A plurality of planetary gears 38 (three in the embodiment) are rotatably supported on a carrier 37 fixed to one surface of the transmission gear 36. The sun gear 39 provided on the outer periphery of the sun gear shaft 35 meshes with all the planetary gears 38 described above.

  A ring gear 40 having inner teeth on the inner peripheral surface and outer teeth on the outer peripheral surface is rotatably fitted to the sun gear shaft 35 via a bearing so that the inner teeth mesh with the plurality of planetary gears 38 respectively. . External teeth on the outer peripheral surface of the ring gear 40 mesh with a pump gear 55 fixed to an input pump shaft 53 protruding from the hydraulic pump 33 into the transmission case 8. The transmission gear 41 fixed to the sun gear shaft 35 at a position behind the ring gear 40 meshes with the motor gear 56 fixed to the output motor shaft 54 protruding from the hydraulic motor 34 into the transmission case 8.

  A transmission gear 42 is attached to the both sides of the sun gear shaft 35 across the transmission gear 41. On the other hand, below the sun gear shaft 35, a rear wheel propulsion shaft 43 extending in parallel with the sun gear shaft 35 in the mission case 8 is rotatably supported via a bearing. A pair of driven gears 44 that are always meshed with the transmission gears 42 of the sun gear shaft 35 are loosely fitted in the longitudinal middle portion of the rear wheel propulsion shaft 43. Between the driven gears 44, 44 of the rear wheel propulsion shaft 43, an auxiliary transmission clutch 45 that interrupts power transmission from the sun gear shaft 35 to the rear wheel propulsion shaft 43 reciprocates along the rear wheel propulsion shaft 43. It is movably fitted.

  A rear end of the rear wheel propulsion shaft 43 that protrudes rearward from the transmission case 8 is connected to the rear wheel final reduction device 13 with a differential limiting mechanism, and is fixed to the front end of the rear wheel propulsion shaft 43. The gear 46 meshes with a gear 48 with a clutch attached to a front wheel propulsion shaft 47 disposed below and in parallel to the rear wheel propulsion shaft 43. A front end portion of the front wheel propulsion shaft 47 that protrudes forward from the mission case 8 is interlocked and connected to a front wheel final reduction device 12 with a differential limiting mechanism.

  As shown in FIG. 5, the planetary gear mechanism 31 is located above the oil level S of the hydraulic oil stored in the lower part of the transmission case 8. The gears 44, 44, and 46 attached to the rear wheel propulsion shaft 43 are configured to rotate in a state where a part of the outer peripheral lower portion is immersed in hydraulic oil.

  In this embodiment, hydraulic oil splashed upward on the outer periphery of each gear 44, 44, 46 by the rotation of each gear 44, 44, 46 on the rear wheel propulsion shaft 43 is transmitted to the planetary gear mechanism 31. The gear 41 and the transmission gears 42 and 42 are exposed. As a result, the planetary gear mechanism 31, the transmission gear 41, and the transmission gears 42 and 42 are lubricated. It should be noted that the planetary gear mechanism 31 (sun gear shaft 35) in the mission case 8 may be arranged so that a part thereof is immersed in the oil surface S of the hydraulic oil.

  The hydrostatic transmission mechanism 32 adjusts the inclination angle of a rotary swash plate (not shown) of the hydraulic pump 33 to change the discharge direction and discharge amount of the hydraulic oil to the hydraulic motor 34, thereby The motor shaft 54 is configured to be able to adjust the rotation direction and the number of rotations. In this embodiment, the hydraulic pump 33 and the hydraulic motor 34 are integrated into a unit by being housed in a transmission case 60 that is externally attached to the upper front portion of the transmission case 8.

  In the mission case 8, the input pump shaft 53 to the hydraulic pump 33 and the output motor shaft 54 from the hydraulic motor 34 are arranged in parallel to the sun gear shaft 35 of the planetary gear mechanism 31. The input pump shaft 53, the output motor shaft 54, and the gears 55 and 56 provided on the shafts 53 and 54 are above the oil level S of the hydraulic oil in the transmission case 8 (the hydraulic oil It is located at the height position where it is not immersed.

  Next, the detailed structure of the planetary gear 38 will be described with reference to FIGS.

  A planetary shaft 62 extending parallel to the sun gear shaft 35 is passed through a support hole 61 formed at the rotation center of the planetary gear 38 via a needle roller bearing 63 which is an example of a bearing. Both longitudinal ends of the planetary shaft 62 are fixed to the carrier 37. A disc-shaped thrust washer 64, which is an example of a washer, is disposed between the front and rear side surfaces of the planetary gear 38 and the inner surface of the carrier 37, respectively. These thrust washers 64 prevent the front and rear side surfaces of the planetary gear 38 from rubbing against the inner surface of the carrier 37, and prevent the end surfaces of the needle rollers constituting the needle roller bearing 63 from contacting the inner surface of the carrier 37. Is to do.

  On one side surface (front side surface in the embodiment) of the planetary gear 38, a plurality of suction grooves 65 for introducing the working oil (functioning as lubricating oil) in the mission case 8 into the support hole 61 are formed. As shown in FIG. 6B, each suction groove 65 of the embodiment is configured to extend from the support hole 61 so as to incline radially outward and toward the downstream side in the rotation direction of the planetary gear 38. . That is, each suction groove 65 of the embodiment extends in a reverse spiral shape from the support hole 61 in the rotation direction. Further, most of each suction groove 65 protrudes radially outward from the thrust washer 64.

  A plurality of discharge grooves 66 for discharging hydraulic oil from the support holes 61 are formed on the other side surface (rear side surface in the embodiment) of the planetary gear 38. As shown in FIG. 6C, each of the discharge grooves 66 of the embodiment has a form extending from the support hole 61 so as to incline radially outward and toward the upstream side in the rotation direction of the planetary gear 38. . That is, each discharge groove 66 of the embodiment extends in a spiral shape from the support hole 61 in the rotation direction. Further, most of each discharge groove 66 protrudes radially outward from the thrust washer 64.

  As shown in FIGS. 6A to 6C, in the embodiment, the front and rear side surfaces of the planetary gear 38 are developed on both sides with the symmetry axis Z of the lateral side surface of the planetary gear 38 orthogonal to the rotation axis of the planetary shaft 62. The suction groove 65 group and the discharge groove 66 group are set to have an asymmetric positional relationship.

  In the above configuration, when the tractor is driven, the hydraulic oil splashed upward on the outer periphery of each gear 44, 44, 46 by the rotation of each gear 44, 44, 46 on the rear wheel propulsion shaft 43 is It is exposed to the planetary gear mechanism 31, the transmission gear 41, and the transmission gears 42 and 42.

  When the hydraulic oil applied to one side of the planetary gear 38 in the planetary gear mechanism 31 enters each suction groove 65, each suction groove 65 extends in a reverse spiral shape from the support hole 61 in the rotation direction. Therefore, the hydraulic oil in each suction groove 65 is pushed radially inward (support hole 61 side) by the peripheral wall of each suction groove 65 as the planetary gear 38 rotates.

  For this reason, the hydraulic oil in each suction groove 65 is forced to flow into the support hole 61, and the planetary gear 38, the needle roller bearing 63 and the planetary shaft 62 are lubricated, and heat is generated by the friction of these 38, 62, and 63. Is suppressed. Accordingly, wear and seizure of the planetary gear 38, the needle roller bearing 63, and the planetary shaft 62 can be suppressed, and the durability thereof can be improved (long life can be achieved).

  In particular, in the embodiment, a plurality of discharge grooves 66 that spirally extend from the support hole 61 in the rotational direction are formed on the other side surface of the planetary gear 38, so that the hydraulic oil flowing into the support hole 61 is It is pushed outward in the radial direction by the centrifugal force accompanying the rotation of the planetary gear 38 and flows into each discharge groove 66. The hydraulic oil in each discharge groove 66 is pushed outward in the radial direction by the peripheral wall of each discharge groove 66 and centrifugal force as the planetary gear 38 rotates, and is discharged to the outside of the planetary gear 38.

  Accordingly, the fluidity of the working oil in the support hole 61 in the planetary gear 38 and, in turn, the lubricity of the planetary gear 38, the needle roller bearing 63 and the planetary shaft 62 can be further improved.

  Although not shown in detail, communication grooves that overlap the respective suction grooves 65 may be formed on the thrust washer 64 facing the group of suction grooves 65 or on the inner surface (may be a spacer or the like) of the carrier 37. Similarly, a communication groove that overlaps each discharge groove 66 may be formed on the thrust washer 64 facing the discharge groove 66 group or the inner surface of the carrier 37 (may be a spacer or the like). These communication grooves need to extend outward in the radius and open toward the periphery. By adopting such a configuration, it becomes possible to further improve the fluidity of the working oil in the support hole 61 in the planetary gear 38 and, consequently, the lubricity of the planetary gear 38, the needle roller bearing 63 and the planetary shaft 62. .

  Further, it is possible to provide only the above-described communication groove and eliminate the suction groove 65 and the discharge groove 66 on the planetary gear 38 side. In this case, one communication groove corresponding to the suction side extends in a reverse spiral shape from the support hole 61 in the rotation direction, and the other communication groove corresponding to the discharge side spirals from the support hole 61 in the rotation direction. It will extend in the shape.

  Each structure of above-mentioned embodiment is not limited to the thing of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

It is the whole tractor side view. It is a schematic plan view of a traveling machine body. It is a top view which shows the power transmission system of a tractor. FIG. 4 is a schematic view taken along the line IV-IV in FIG. 3 showing the positional relationship between various shafts and gears in the mission case. It is principal part side sectional drawing of a hydraulic and mechanical transmission. (A) is an enlarged side sectional view of the planetary gear, (b) is an enlarged front view of the planetary gear, and (c) is an enlarged rear view of the planetary gear.

Explanation of symbols

1 traveling machine body 4 engine 8 transmission case 9 hydraulic / mechanical transmission 31 planetary gear mechanism 35 sun gear shaft 37 carrier 38 planetary gear 39 sun gear 40 ring gear 61 support hole 62 planetary shaft 63 needle roller bearing (bearing)
64 Thrust washer (washer)
65 Suction groove 66 Exhaust groove

Claims (2)

A carrier, a planetary shaft attached to the carrier, a planetary gear rotatably supported on the planetary shaft through a bearing, and a planetary shaft that is interposed between the planetary gear and the carrier. In a planetary gear mechanism including a fitted washer,
On one side surface of the planetary gear, a suction groove for introducing hydraulic oil into a support hole into which the planetary shaft and the bearing fit extends radially outward from the support hole and toward the downstream side in the rotation direction of the planetary gear. Formed to be inclined,
Lubricating structure of planetary gear mechanism. On the other side surface of the planetary gear, a discharge groove for discharging hydraulic oil from the support hole extends radially outward from the support hole and is inclined toward the upstream side in the rotation direction of the planetary gear. Formed,
The lubricating structure of the planetary gear mechanism according to claim 1.

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