Lubrication structure of gear mechanism

Abstract

To provide a lubrication structure of a gear mechanism capable of quickly supplying lubricant to an engagement surface or the like even during start of operation.SOLUTION: A lubrication structure 1 of a gear mechanism 2 is configured such that in a shaft 8 penetrating a gear 5 along a central axis of a gear 5, a supply oil path 12 is formed so as to open at one end part of the shaft 8 and extend along the central axis of the shaft 8, and a discharge oil path 13 is formed so as to extend from the supply oil path 12 in a radial direction of the shaft 8 and open onto an outer peripheral surface of the shaft 8. The supply oil path 12 has a small diameter oil path 14 on the one end part side of the shaft 8, and a large diameter oil path 15 that extends from the small diameter oil path 14 in a central axial direction of the shaft 8 and has an inner diameter larger than the small diameter oil path 14. The discharge oil path 13 extends from the large diameter oil path 15 in the radial direction of the shaft 8.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a structure for supplying lubricating oil to meshing surfaces of a gear mechanism. [Background technology]

[0002] Patent Document 1 discloses a lubrication structure for a driving force transmission device configured to adjust the amount of lubricating oil supplied to a planetary gear and an engagement element according to a change in the rotation speed. In the structure of Patent Document 1, an oil catch plate is attached to one side in the axial direction of a carrier constituting a planetary gear. The oil catch plate supplies lubricating oil supplied from an axial oil passage of an input shaft to a meshing surface of the planetary gear and frictional engagement elements arranged on the outer periphery side of the planetary gear. A radially extending passage configured to supply lubricating oil to the frictional engagement elements is formed in the oil catch plate. An opening / closing valve that opens and closes according to the rotation speed of the oil catch plate is provided in the passage. The opening / closing valve is configured to move a valve body of the opening / closing valve radially outward to open the passage when the rotation speed of the oil catch plate exceeds a predetermined rotation speed that is set in advance. As a result, the opening / closing valve is opened when the rotation speed of the oil catch plate becomes high, so that the amount of lubricating oil supplied to the frictional engagement elements through the passage can be increased. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO 2014 / 54490 Summary of the Invention [Problem to be solved by the invention]

[0004] In the structure described in Patent Document 1, when the supply of lubricating oil to the axial oil passage and the rotation of the input shaft are stopped, the lubricating oil flows down from the gaps between the parts and the oil passages to the outside of the driving force transmission device due to gravity, etc. In other words, the lubricating oil is discharged from the through hole (oil passage) formed in the pinion shaft and the axial oil passage. The pinion shaft may be located relatively downstream in the path through which the oil is supplied. In that case, it takes time for the lubricating oil discharged from a supply source such as an oil pump to reach the pinion shaft. Therefore, when the operation of the stopped planetary gear is resumed, the supply of lubricating oil to the meshing surfaces of each gear may be delayed.

[0005] The present invention has been made in consideration of the above-mentioned technical problems, and aims to provide a lubrication structure for a gear mechanism that is capable of quickly supplying lubricating oil to meshing surfaces, etc., even at the start of operation. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a lubrication structure for a gear mechanism, in which a shaft penetrating a gear along the central axis of the gear is formed with a supply oil passage that opens at one end of the shaft and extends along the central axis of the shaft, and a discharge oil passage is formed that extends from the supply oil passage in a radial direction of the shaft and opens onto the outer circumferential surface of the shaft, characterized in that the supply oil passage has a small diameter oil passage on one end side of the shaft, and a large diameter oil passage that extends from the small diameter oil passage in the central axial direction of the shaft and has an inner diameter larger than the small diameter oil passage, and the discharge oil passage extends from the large diameter oil passage in the radial direction of the shaft. Effect of the Invention

[0007] According to the lubrication structure of the gear mechanism of the present invention, when the gear mechanism rotates, oil can be supplied to the meshing surfaces of the gears through the supply oil passage and the discharge oil passage formed in the shaft. In addition, when the gear mechanism stops, a part of the large-diameter oil passage is recessed relative to the small-diameter oil passage, so that the oil remains accumulated in the recessed part. Therefore, when the stopped gear mechanism starts to rotate, the oil held in the oil reservoir is immediately supplied to the meshing surfaces of the gears. Therefore, even if there is a delay in the supply of oil discharged from a supply source such as an oil pump to the oil passage formed in the shaft when the gear mechanism is restarted, the oil can be quickly supplied to each meshing surface of the gear mechanism, so that the lubrication state of the gear mechanism can be improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view showing an example of a lubrication structure for a gear mechanism according to an embodiment of the present invention. [Diagram 2] 2(a) is a cross-sectional view of a pinion pin for explaining the structure of a first oil passage in an embodiment of the present invention, and FIG. 2(b) is a cross-sectional view of the pinion pin cut in the axial direction, and FIG. 2(b) is a cross-sectional view taken along the AA cutting line in FIG. 2(a). [Diagram 3] FIG. 4 is a cross-sectional view for explaining another example of a lubrication structure in an embodiment of the present invention, the cross-sectional view corresponding to the cross-sectional view of the pinion pin shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below based on the embodiment shown in the drawings. Note that the embodiment described below is merely one example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0010] Fig. 1 shows an example of a lubrication structure 1 in an embodiment of the present invention. The lubrication structure 1 shown in Fig. 1 is applied to a planetary gear mechanism 2, which corresponds to the gear mechanism in the embodiment of the present invention. The planetary gear mechanism 2 is a gear mechanism that generates a differential action by three rotating elements, similar to conventionally known planetary gear mechanisms, and the planetary gear mechanism 2 shown in Fig. 1 is a so-called single pinion type planetary gear mechanism 2.

[0011] The planetary gear mechanism 2 includes three rotating elements, namely, a sun gear 3, a ring gear 4 which is an internal gear provided concentrically with the sun gear 3, and a carrier 6 which is arranged between the sun gear 3 and the ring gear 4 and holds a plurality of pinion gears 5 (planetary gears) meshed with the sun gear 3 and the ring gear 4 so as to be rotatable and revolvable. The plurality of pinion gears 5 are arranged at equal intervals in the rotation direction. As an example, the planetary gear mechanism 2 shown in FIG. 1 has a sun gear 3 which is integrated with an input shaft 7 and serves as an input element, a ring gear 4 which is connected to a case (not shown) or the like and serves as a fixed element, and a carrier 6 which is connected to an output member (not shown) or the like and serves as an output element. For convenience of explanation, only one of the plurality of pinion gears 5 is shown in FIG. 1.

[0012] As shown in FIG. 1, the carrier 6 holds the multiple pinion gears 5 by connecting the ends of the pinion pins 8 inserted into the pinion gears 5. Specifically, as shown in FIG. 1, the pinion pins 8, which are longer than the pinion gears 5 in the axial direction, are inserted into the pinion gears 5. The pinion pins 8 protrude slightly from both ends of the pinion gears 5 in the axial direction. The carrier 6 has plate portions located on both sides of the pinion gears 5 in the rotational axis direction, and the pinion pins 8 are held by the carrier 6 by connecting the protruding portions to the plate portions of the carrier 6. By connecting the carrier 6 and the multiple pinion pins 8 in this way, the multiple pinion pins 8 are connected to each other, and the multiple pinion gears 5 can revolve by an angle corresponding to the rotation angle of the carrier 6 while being arranged at equal intervals in the rotational direction.

[0013] As shown in Fig. 1, a bearing 9 is provided between the pinion pin 8 and the pinion gear 5. This allows relative rotation between the pinion gear 5 and the pinion pin 8, allowing the pinion gear 5 to rotate on its axis. The carrier 6 serves as an output element, causing the pinion gear 5 to revolve around the sun gear 3. As a result, the pinion pin 8 is subjected to centrifugal force when the carrier 6 rotates. The pinion gear 5 corresponds to a gear in this embodiment of the invention, and the pinion pin 8 corresponds to a shaft in this embodiment of the invention.

[0014] In the planetary gear mechanism 2 configured in this manner, a lubrication structure 1 is formed to supply oil for lubrication and cooling to each meshing surface of the sun gear 3, the pinion gear 5, and the ring gear 4, as well as to the bearing 9. For example, oil pumped up by an electric or mechanical oil pump (not shown) is supplied to a hollow portion 10 formed inside the input shaft 7. The oil is supplied to the planetary gear mechanism 2 via an oil passage 11 formed inside the pinion pin 8.

[0015] As shown in Fig. 1, Fig. 2(a) and Fig. 2(b), the oil passage 11 formed in the pinion pin 8 has a first oil passage 12 and a second oil passage 13. The first oil passage 12 extends in the axial direction of the pinion pin 8, with one end opening in the axial direction and the other end extending to near the center in the axial direction of the pinion pin 8 and then closed. The first oil passage 12 is formed along the central axis of the pinion pin 8. One end of the first oil passage 12 opens in the axial direction of the pinion pin 8. The first oil passage 12 corresponds to the supply oil passage in this embodiment of the present invention.

[0016] As shown in Fig. 1 and Fig. 2(a), the second oil passage 13 is formed extending in the radial direction of the pinion pin 8, and one end of the second oil passage 13 is connected to the other end of the first oil passage 12. The other end of the second oil passage 13 opens to the outer peripheral surface of the pinion pin 8. The second oil passage 13 is formed in the pinion pin 8 so as to be located farther from the rotation center of the carrier 6 than the first oil passage 12. In other words, the second oil passage 13 is formed so that when the pinion pin 8 rotates, oil is discharged from the opening of the second oil passage 13 by centrifugal force. The second oil passage corresponds to the discharge oil passage in the embodiment of the present invention.

[0017] The first oil passage 12 has an oil supply passage 14 and an oil reservoir 15. The oil supply passage 14 corresponds to the small diameter oil passage in the embodiment of the present invention, and is a portion that extends in the axial direction from an opening on one end side of the first oil passage 12 inside the pinion pin 8, and is an oil passage with a relatively small inner diameter. An oil reservoir 15 is formed continuously with the oil supply passage 14 on the opposite side to the one end side in the axial direction.

[0018] The oil reservoir 15 corresponds to the large-diameter oil passage in the embodiment of the present invention, and is formed on the other end side of the first oil passage 12 inside the pinion pin 8, as shown in FIG. 1 and FIG. 2(a), and extends in the axial direction from the oil supply passage 14. The oil reservoir 15 is formed to have a larger inner diameter than the oil supply passage 14. Specifically, the oil reservoir 15 is formed on the same central axis as the central axis of the oil supply passage 14, and has a larger inner diameter than the oil supply passage 14. In other words, the oil reservoir 15 is formed so as to be recessed radially outward from the oil supply passage 14. Therefore, when the oil that has entered the first oil passage 12 reaches the oil reservoir 15, the oil is difficult to be discharged from the first oil passage 12 to the outside. In addition, the second oil passage 13 is formed on the inner wall of the oil reservoir 15. Therefore, when centrifugal force acts on the oil stored in the oil storage portion 15, the stored oil is quickly scattered from the second oil passage 13.

[0019] An oil guide portion 16 is attached to the first oil passage 12. The oil guide portion 16 is a plate for efficiently supplying the oil discharged from the input shaft 7 to the oil passage. The oil guide portion 16 is composed of a main body portion 17 that receives oil scattered from the input shaft 7, and a shaft portion 18 that extends in the axial direction from the main body portion 17 and has a through hole formed in the center.

[0020] As shown in Fig. 1, the main body 17 is cut outward in the radial direction and has a U-shaped cross section facing downward. In other words, the main body 17 is formed in a rectangular shape overall, with one of the four sides being open. The open portion faces the splash section 19 of the input shaft 7 from which the oil is discharged. A shaft section 18 is formed on the cut-out inner surface of the main body 17 on the side of the first oil passage 12.

[0021] As shown in Fig. 2(a), the shaft portion 18 is formed to extend in the same axial direction as the pinion pins 8, and is inserted inside the oil supply passage 14 in the first oil passage 12. The shaft portion 18 extends to the oil reservoir 15. The outer diameter of the shaft portion 18 is formed to be the same as or slightly smaller than the inner diameter of the oil supply passage 14. Note that the number of main body portions 17 and shaft portions 18 in the oil guide portion 16 may be the same as the number of pinion pins 8, or may be less than the number.

[0022] With this configuration, oil discharged from the oil pump is supplied to the hollow portion 10 of the input shaft 7, and part of the oil is subjected to centrifugal force due to the rotation of the input shaft 7 and is scattered from the scattering portion 19 to the oil guide portion 16. The oil scattered to the oil guide portion 16 is collected by the inner surface of the main body portion 17 of the oil guide portion 16, which is formed with a U-shaped cross section, and flows into the through hole of the shaft portion 18. Therefore, compared to the case where the oil guide portion 16 is not provided, the oil is more easily supplied to the first oil passage 12 of the pinion pin 8. Then, the oil supplied to the shaft portion 18 inserted in the oil supply passage 14 is supplied to the oil reservoir portion 15 of the first oil passage 12. Since the second oil passage 13 opening on the outer peripheral surface of the pinion pin 8 is communicated with the oil reservoir portion 15, the rotation of the carrier 6, i.e., the rotation (revolution) of the pinion pin 8 causes the oil to scatter from the opening of the second oil passage 13. This makes it possible to supply oil to the meshing surfaces of the gears 3, 4, and 5 in the planetary gear mechanism 2, and the like.

[0023] In addition, as the rotation speed of the pinion pin 8 decreases, the centrifugal force acting on the pinion pin 8 decreases, and the oil gradually stops scattering from the second oil passage 13. Therefore, the oil that is not scattered remains in the first oil passage 12. At this time, the oil reservoir 15, which is recessed radially outward from the oil supply passage 14 in the first oil passage 12, prevents the oil from being discharged from the second oil passage 13. That is, even if the rotation of the pinion pin 8 stops, a part of the oil supplied to the first oil passage 12 remains stored in the oil reservoir 15. Therefore, when the stopped pinion pin 8 rotates again and the centrifugal force becomes large, the stored oil can be immediately supplied from the second oil passage 13 to the meshing surfaces of the gears 3, 4, and 5. The pinion pin 8 may be located relatively downstream, that is, at the end, on the path through which the oil is supplied. Even in such a case, it is possible to prevent or suppress delays in the supply of oil to the oil passage 11 of the pinion pin 8 and to the meshing surfaces of the gears 3, 4, and 5 of the planetary gear mechanism.

[0024] Next, another lubrication structure 20 according to an embodiment of the present invention will be described. FIG. 3 is a cross-sectional view for explaining the other lubrication structure 20, and shows a cross-sectional view corresponding to FIG. 2(a). In FIG. 3, only parts necessary for the explanation are given reference numerals, and the same configurations as those in FIG. 1 and FIG. 2(a) are given the same reference numerals, and the explanations thereof are omitted or simplified. As shown in FIG. 3, in the other lubrication structure 20, the inner diameter of the oil reservoir 22 in the first oil passage 21 is configured to be equal to that of the oil supply passage 23. That is, the inner diameter of the oil reservoir 22 and the inner diameter of the oil supply passage 23 are formed to be the same size. In addition, the shaft portion 25 in the oil guide portion 24 is fitted into the oil supply passage 23 of the first oil passage 21. That is, the outer diameter of the shaft portion 25 and the inner diameter of the oil supply passage 23 are the same, or the outer diameter of the shaft portion 25 is formed to be slightly larger than the inner diameter of the oil supply passage 23. Therefore, the shaft portion 25 and the oil supply passage 23 are attached with no gap in the radial direction.

[0025] According to the other lubrication structure 20, the inner diameter of the oil supply passage 23 in the first oil passage 21 and the inner diameter of the oil reservoir 22 are formed to have the same dimensions. Therefore, for example, the number of processing steps and processing costs when forming the first oil passage 21 by drilling or the like can be reduced. In addition, the shaft portion 25 of the oil guide portion 24 and the oil supply passage 23 of the first oil passage 21 are fitted together. That is, the gap between the shaft portion 25 and the oil supply passage 23 in the radial direction is sealed, so that the oil is prevented from leaking out from the gap. Therefore, when the centrifugal force no longer acts on the pinion pin 8, the oil can be left in the lower part of the oil reservoir 22 in an amount corresponding to the plate thickness of the shaft portion 25. Therefore, in the other lubrication structure 20, the same effect as the lubrication structure shown in FIG. 2 can be obtained, and the planetary gear mechanism as a whole can be in a good lubricated state. [Explanation of symbols]

[0026] 1,20 Lubrication structure 2 Planetary gear mechanism (gear mechanism) 5 Pinion gear 8,23 Pinion pin (shaft) 11 Oil road 12,21 First oil passage (supply oil passage) 13 2nd oil path (discharge oil path) 14 Oil supply passage (small diameter oil passage) 15,22 Oil reservoir (large diameter oil passage)

Claims

[Claim 1] A lubrication structure for a gear mechanism, comprising: a shaft penetrating a gear along a central axis of the gear; an oil supply passage opening at one end of the shaft and extending along the central axis of the shaft; and an oil discharge passage extending from the oil supply passage in a radial direction of the shaft and opening on an outer circumferential surface of the shaft, The oil supply passage includes a small diameter oil passage on one end side of the shaft, a large diameter oil passage extending from the small diameter oil passage in a central axial direction of the shaft and having an inner diameter larger than that of the small diameter oil passage; The discharge oil passage extends from the large diameter oil passage in a radial direction of the shaft. A lubrication structure for a gear mechanism.

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