JP2012149692A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device capable of increasing a supply amount of lubricant to a pinion gear, the lubricant being thrown to the center side of a case from a drive pinion.SOLUTION: The differential device 1 includes: a pair of side gears 5 and three pinion gears 9 which are accommodated in a rotating case 2; supports 10 formed on the case 2, and configured to revolve as a ring gear 3 rotates and rotatably support the pinion gears 9; and an opening 11 formed between the supports 10, and connecting the inside of the case 2 with the outside thereof to enable supply of lubricant to the inside of the case 2 from the outside of the case 2. The pinion gear 9 has a bottom face 21 of a gear part 19, and a support shaft 22 provided coaxially with the rotational axis of the gear part 19 and protruding from the bottom face 21. The support 10 includes: a bottom receiving surface 23 for rotatably supporting the bottom face 21 of the pinion gear 9 by surface contact; and a support hole 24 for supporting the support shaft 22 of the pinion gear 9 rotatably, and for connecting the inside and the outside of the case 2.

Description

  The present invention relates to a differential used in a vehicle such as an automobile, and more particularly to a differential capable of increasing the amount of lubricating oil supplied to a pinion gear.

  A vehicle such as an automobile is equipped with a differential device as a part of a power transmission system that transmits an output of an internal combustion engine (hereinafter simply referred to as an engine) to driving wheels. This differential device transmits power from the transmission to the left and right drive wheels, and when there is a deviation in the rotational speed of these drive wheels, the pair of side gears rotate relative to each other by rotating the pinion gear. The differential rotation of the drive wheel is allowed.

  By the way, in this type of differential device, generally, a pinion shaft is inserted into a through-hole formed in the shaft center of the pinion gear, and two pinion gears are supported by one pinion shaft, whereby the pinion gear falls down. I try to prevent it. However, in the configuration in which the pinion gear is supported by the pinion shaft in this way, it is necessary to form a through hole in the pinion gear, and considering the strength of the pinion gear, it is difficult to reduce the size of the pinion gear. There was a problem that it became difficult to make it easier.

  In order to solve this, for example, a differential projection in which a support projection for supporting each pinion gear from the side is formed inside the case, and the pinion shaft is omitted by preventing the pinion gear from falling down by the support projection. Has been developed (see, for example, Patent Document 1).

  As shown in FIGS. 11 and 12, the differential device 100 includes a rotatable case 101, a ring gear 103 composed of a hypoid gear fixed to the flange 102 of the case 101, and a drive composed of a hypoid pinion meshing with the ring gear 103. A pinion 104, a side gear 105 made of a pair of bevel gears housed in the case 101 and rotatable independently of the case 101, a drive shaft 106 rotating integrally with the side gear 105, and a pair of bevel gears meshing with the side gear 105 A pinion gear 107, a pair of support portions 108 provided on the case 101 and rotatably supporting the bottom surface 107a of the pinion gear 107, and protruding from the support portion 108 to the inside of the case 101 and rotating the pinion gear 107 from the side. Possible A support protrusion 109 which includes an opening 110 that communicates the inside and outside of the space of the case 101 while being formed between the supporting portion 108. The support protrusion 109 is formed adjacent to a position where the pinion gear 107 is sandwiched in the circumferential direction of the case 101. The support protrusion 109 is exposed in the opening 110.

  According to the differential device 100, the pinion shaft penetrating the gear portion can be omitted by providing the support protrusion 109 in order to prevent the pinion gear 107 from falling, and therefore, the pinion shaft is inserted into the pinion gear 107. There is no need to provide a through hole. For this reason, since the pinion gear 107 can be reduced in size, the differential device 100 can be reduced in size.

  By the way, as for the supply route of the lubricating oil to the pinion gear 107 of this type of differential device 100, the route that was conventionally considered to have the largest supply amount of the lubricating oil is scraped to the top of the ring gear 103 by the rotation of the ring gear 103. The raised lubricating oil flowed down from above the opening 110 and passed through the opening 110 to reach the pinion gear 107. On the other hand, as a result of intensive studies by the inventor of the present application, the lubricating oil lifted by the ring gear 103 is blown to the center side of the case 101 by the drive pinion 104 meshing with the ring gear 103 (FIGS. 11 and 12). It is found that the supply amount is larger in the path that passes through the opening 110 and is supplied to the pinion gear 107 from the side. That is, at the meshing portion of the ring gear 103 and the drive pinion 104, the pumping effect toward the center side of the ring gear 103 occurs due to the closeness and slippage of the tooth surfaces of the ring gear 103 and the drive pinion 104, and the lubricating oil is on the center side of the case 101 It was speculated that it would be skipped.

JP 2008-256083 A

  However, in the configuration of the differential device 100 as described above, in order to support the pinion gear 107, the support protrusion 109 protruding to the inside of the case 101 is provided, and the support protrusion 109 is the circumferential direction of the case 101 of the pinion gear 107. Since the support protrusion 109 is exposed to the opening 110, the lubricating oil which is blown to the side from the drive pinion 104 and enters the case 101 through the opening 110 is blocked. End up. As a result, there is a problem that the amount of lubricating oil supplied to the pinion gear 107 is reduced as compared with the case where the support protrusion 109 is not present. When the differential device 100 is operated for a long time with a small amount of lubricant supplied, there is a possibility that seizure may occur between the support portion 108 and the support protrusion 109 with which the pinion gear 107 slides. .

  In order to solve this problem, it is conceivable to employ lubricating oil supply means such as a pump for supplying lubricating oil to the pinion gear 107, but the number of parts increases and installation space is required for that, and the weight of the vehicle is low. Is also not preferable.

  The present invention has been made to solve the conventional problems as described above, and provides a differential device capable of increasing the supply amount of lubricating oil blown from the drive pinion to the center side of the case to the pinion gear. With the goal.

  In order to achieve the above object, the differential device according to the present invention is (1) a rotatable case, fixed to the case coaxially, and at least a part of the differential is immersed in the lubricating oil, and the lubricating oil is swept up by rotation. A ring gear comprising a hypoid gear, a drive pinion comprising a hypoid pinion meshing with the ring gear, a first side gear comprising a bevel gear housed in the case and coaxially supported by the case and rotatably supported by the case; A first drive shaft coupled to the first side gear and integrally rotating; and a bevel gear housed in the case and coaxially opposed to the first side gear and rotatably supported by the case. A second side gear, and a second drive shaft connected to the second side gear and rotating integrally therewith. Two or more pinion gears comprising bevel gears that are housed in the case and have gear portions that mesh with the first side gear and the second side gear, and are formed in the case and swivel as the ring gear rotates. And a support portion that rotatably supports the pinion gear, and is formed between the support portions and communicates with the inside and outside of the case so that the lubricating oil can be supplied from the outside of the case to the inside of the case. In the differential including the opening, the pinion gear includes a bottom surface of the gear portion, and a support shaft that is coaxial with the rotation axis of the gear portion and protrudes from the center of the bottom surface, and the support portion includes: A bottom receiving surface that rotatably supports the bottom surface of the pinion gear by surface contact; and a support surface that rotatably supports the support shaft of the pinion gear. And having a support hole communicating the inside and outside of the case.

  With this configuration, the pinion gear is self-supporting because the support shaft of the pinion gear fits into the support hole of the support portion and is rotatably supported, so that a conventional support projection for supporting the pinion gear from the periphery is unnecessary. Thus, the lubricating oil blown from the drive pinion to the center of the case enters the inside of the case through the opening without being blocked by the support protrusion, and is supplied to the pinion gear. Thereby, the supply amount to the pinion gear of the lubricating oil skipped from the drive pinion can be increased. Further, the lubricating oil supplied to the pinion gear reduces friction at the meshing portion between the pinion gear, the first side gear and the second side gear, and reaches the bottom surface of the pinion gear and the support shaft by centrifugal force due to rotation of the case. Friction between the bottom surface and the support shaft and the support portion is reduced.

  Further, since the support hole communicates with the inside and outside of the case, the lubricating oil is discharged to the outside of the case by centrifugal force due to the rotation of the case without being stored in the support hole. For this reason, dust such as metal powder does not accumulate in the support hole together with the lubricating oil unlike the case where the support hole has a bottom, and the rotational resistance of the pinion gear is increased by the dust accumulated in the support hole. Can be prevented.

  In the differential device described in (1) above, (2) the bottom receiving surface is preferably a curved concave shape having a smaller radius of curvature than the distance from the rotating shaft of the case to the bottom receiving surface. . With this configuration, when the case rotates, the lubricating oil on the bottom receiving surface is guided from the outer peripheral side to the center side by the centrifugal force. As a result, the flow rate of the lubricating oil flowing from the periphery of the bottom receiving surface to the outside of the case through the support hole can be increased, and the effect of increasing the amount is particularly high when the case rotates at high speed, and the pinion gear is seized. The reliability to prevention can be improved.

  In the differential device described in (1) or (2) above, (3) the pinion gear is formed on the bottom receiving surface and connects the outer peripheral edge portion and the inner peripheral edge portion of the bottom receiving surface. It is preferable that a bottom receiving surface lubricating oil path including a groove for guiding the lubricating oil between the bottom surface and the bottom receiving surface to the support hole is provided. With this configuration, the bottom bearing surface lubricating oil passage guides the lubricating oil between the bottom surface of the pinion gear and the bottom bearing surface to the support hole, so that the flow rate of the lubricating oil passing through the bottom bearing surface can be increased when the case rotates. In particular, when the case rotates at a high speed, the effect of increasing the amount becomes high, and the reliability of preventing the seizure of the pinion gear can be improved.

  In the differential device according to the above (1) to (3), (4) a peripheral portion on the inner side of the case and a peripheral portion on the outer side of the case are formed in the support hole. It is preferable that a support hole lubricating oil path including a groove for guiding the lubricating oil between the support shaft and the support hole of the pinion gear to the outside of the case is provided. With this configuration, the support hole lubricating oil path guides the lubricating oil between the support shaft and the support hole to the outside of the support hole, so that the flow rate of the lubricating oil passing through the support hole can be increased when the case rotates, and the case During the high speed rotation, the effect of the increase is particularly high, and the reliability for preventing the seizure of the pinion gear can be improved.

  In the differential device described in (1) to (4) above, (5) the peripheral portion of the bottom receiving surface and the outer peripheral edge portion of the bottom receiving surface are connected, and the lubricating oil in the peripheral portion is It is preferable to provide a peripheral lubricating oil passage composed of a groove for guiding to the bottom receiving surface. With this configuration, the peripheral lubricating oil passage guides the peripheral lubricating oil to the bottom receiving surface, so that the flow rate of lubricating oil supplied to the bottom receiving surface during rotation of the case can be increased, and the high speed of the case During rotation, the effect of increasing the amount is particularly high, and the reliability for preventing the pinion gear from being seized can be improved.

  In the differential device according to the above (1) to (5), it is preferable that (6) at least one of the bottom bearing surface lubricating oil passage and the support hole lubricating oil passage is spiral. With this configuration, the bottom bearing surface lubricating oil passage and the support hole lubricating oil passage are perpendicular to the rotation direction of the pinion gear, and the pinion gear between the bottom surface of the pinion gear and the support shaft and the support portion of the case in the rotation direction of the pinion gear. Resistance can be reduced. As a result, the pinion gear can be smoothly rotated, and wear of the bottom surface and the sliding contact portion between the support shaft and the support portion can be suppressed.

  In the differential device according to the above (1) to (5), (7) at least one of the bottom bearing surface lubricating oil path, the support hole lubricating oil path, and the peripheral lubricating oil path is linear. Preferably there is. With this configuration, the bottom bearing surface lubricating oil path, the support hole lubricating oil path, and the surrounding lubricating oil path are compared with the case where the bottom bearing surface lubricating oil path, the supporting hole lubricating oil path, and the surrounding lubricating oil path are curved. The forming operation with the road can be facilitated, and the component cost can be reduced.

  In the differential device according to (1) to (7) above, (8) three pinion gears are provided every 120 degrees around the rotation shafts of the first side gear and the second side gear. Is preferred. With this configuration, since the pinion gear and the opening are opposed to each other with the rotation shafts of the first side gear and the second side gear interposed therebetween, the lubricating oil blown from the drive pinion to the center side of the case is removed from the opening. When it enters the case, it is directly supplied to the pinion gear located on the opposite side. Thereby, the flow volume of the lubricating oil supplied to the pinion gear can be increased, and the reliability for preventing the seizure of the pinion gear can be improved.

  Here, when two pinion gears are provided every 180 degrees around the rotation shafts of the first side gear and the second side gear, the lubricating oil blown from the drive pinion is introduced into the case from the opening. Even if it enters, it may jump out of the case from the opening on the opposite side, and in this case, it is difficult to increase the amount of lubricating oil supplied to the pinion gear. Therefore, in the present invention, by providing three pinion gears every 120 degrees around the rotation shafts of the first side gear and the second side gear, the lubricating oil that has been blown off from the drive pinion and entered from the opening is provided in the other openings. It is supplied directly to the pinion gear without jumping out from the part.

  In the differential device described in (1) to (7) above, (9) two pinion gears are provided every 180 degrees around the rotation shafts of the first side gear and the second side gear. Is preferred. With this configuration, the number of parts can be reduced as compared with the case where three pinion gears are provided, so that the part cost can be reduced.

  According to the present invention, since the pinion gear is self-supporting by fitting the support shaft of the pinion gear into the support hole of the support portion, the conventional support projection for supporting the pinion gear from the periphery is not required, and the drive pinion Since the lubricating oil blown to the center side of the case is not blocked by the support protrusions, a differential device that can increase the supply amount of the lubricating oil blown from the drive pinion to the pinion gear can be provided.

1 is a schematic cross-sectional view showing a differential device according to an embodiment of the present invention. It is the schematic longitudinal cross-sectional view cut | disconnected by the II-II line | wire of FIG. 1 which shows the differential gear which concerns on embodiment of this invention. It is a perspective view which shows the state which removed the ring gear of the differential gear which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the pinion gear and support part of the differential gear which concern on embodiment of this invention. It is the schematic which shows the state which looked at the support part of the differential gear which concerns on embodiment of this invention from the center side of the case. It is the schematic which shows the state which looked at the example which the bottom receiving surface lubricating oil path of the support part of the differential device which concerns on embodiment of this invention is one spiral from the center side of the case. It is the schematic which shows the state which looked at the example from which the bottom bearing surface lubricating oil path of the support part of the differential device which concerns on embodiment of this invention is linear shape from the center side of the case. It is the schematic which shows the state which looked at the example where the bottom bearing surface lubricating oil path of the support part of the differential device which concerns on embodiment of this invention is curvilinear from the center side of the case. It is a schematic longitudinal cross-sectional view which shows the example which can divide | segment the case of the differential gear which concerns on embodiment of this invention. FIG. 3 is a schematic cross-sectional view showing an example in which there are two pinion gears of the differential gear according to the embodiment of the present invention. It is a schematic cross-sectional view showing a conventional differential device. It is a perspective view which shows the state which removed the ring gear of the conventional differential gear.

  Hereinafter, embodiments of a differential device of the present invention will be described with reference to the drawings. In the present embodiment, an example in which the differential device of the present invention is applied to an automobile is shown.

First, the configuration of the differential device 1 according to the present embodiment will be described.
As shown in FIGS. 1 to 3, the differential device 1 includes a rotatable case 2, a ring gear 3 composed of a hypoid gear fixed to the case 2, a drive pinion 4 composed of a hypoid pinion meshing with the ring gear 3, A first side gear 5 composed of a bevel gear housed in the case 2, a first drive shaft 6 connected to the first side gear 5, and a second side gear 7 composed of a bevel gear housed in the case 2 The second drive shaft 8 coupled to the second side gear 7, the three pinion gears 9, the three support portions 10, and the support portions 10 are formed and communicated between the inside and outside of the case 2. The opening part 11 to be provided is provided.
The differential 1 is housed in a housing 29 of the power transmission device.

  The case 2 has a substantially cylindrical shape and is rotatable about a central axis of the cylinder as a rotation axis C. The case 2 includes a first cylindrical portion 12, a second cylindrical portion 13, a flange portion 14 formed on the outer peripheral side of the first cylindrical portion 12, and the first cylindrical portion 12 and the second cylindrical portion. And a connecting portion 15 for connecting 13 to each other.

  The connecting portion 15 is provided at three positions every 120 degrees in the circumferential direction of the case 2 and connects the first cylindrical portion 12 and the second cylindrical portion 13 so as to be coaxial with the rotation axis C. is doing. The connecting portion 15 is turned around the rotation axis C as the case 2 rotates.

  A space surrounded by the first cylindrical portion 12, the connecting portion 15, and the second cylindrical portion 13 is an accommodation space 16. A through hole 17 is formed in the connecting portion 15. A cap 18 is fixed to the through hole 17 by press fitting. The cap 18 is formed with a support portion 10 to be described later. That is, the pinion gear 9 and the opening 11 face each other with the rotation axis C of the case 2 interposed therebetween.

  On the second cylindrical portion 13 side of the flange portion 14, the ring gear 3 having the rotation axis C as the rotation center is fixed by screwing. The ring gear 3 is installed so that a part of the lower part is immersed in the lubricating oil 35 stored in the bottom of the housing 29. The ring gear 3 is adapted to lift up the lubricating oil 35 by rotation. The drive pinion 4 is connected to a drive source such as an engine (not shown) via a transmission (not shown).

  A first drive shaft 6 is rotatably supported by the first cylindrical portion 12. A second drive shaft 8 is rotatably supported by the second cylindrical portion 13. The first drive shaft 6 and the second drive shaft 8 have the rotation axis C as the center of rotation.

  The accommodation space 16 of the case 2 accommodates the first side gear 5, the second side gear 7, and the pinion gear 9. A spline hole 5a is formed in the first side gear 5. A spline shaft (not shown) is formed at the tip of the first drive shaft 6. By fitting the spline shaft of the first drive shaft 6 into the spline hole 5 a of the first side gear 5, the first side gear 5 and the first drive shaft 6 are centered on the rotation axis C with respect to the case 2. Are supported so as to be integrally rotatable.

  A spline hole 7 a is formed in the second side gear 7. A spline shaft (not shown) is formed at the tip of the second drive shaft 8. By fitting the spline shaft of the second drive shaft 8 into the spline hole 7 a of the second side gear 7, the second side gear 7 and the second drive shaft 8 are centered on the rotation axis C with respect to the case 2. Are supported so as to be integrally rotatable. The first side gear 5 and the second side gear 7 are installed with their gear faces facing each other.

  The pinion gear 9 is a bevel gear housed in the case 2, is provided between the first side gear 5 and the second side gear 7, and meshes with the first side gear 5 and the second side gear 7. . The pinion gear 9 is provided in each connecting portion 15 and is provided every 120 degrees around the rotation axes of the first side gear 5 and the second side gear 7.

  As shown in FIGS. 1 and 4, the pinion gear 9 has a gear portion 19 and a bottom portion 20. The bottom portion 20 of the pinion gear 9 includes a bottom surface 21 of the gear portion 19 and a support shaft 22 that is coaxial with the rotation shaft of the gear portion 19 and protrudes from the bottom surface 21. The gear portion 19 and the bottom portion 20 are integrally formed. The bottom surface 21 has a curved convex shape.

  The pinion gear 9 revolves around the rotation axis C as the case 2 rotates. When the case 2 rotates, if there is no difference in the rotation speed between the first drive shaft 6 and the second drive shaft 8, the pinion gear 9 does not rotate but only revolves around the rotation axis C. It has become. In addition, when the case 2 rotates, if there is a difference in the rotational speed between the first drive shaft 6 and the second drive shaft 8, the pinion gear 9 will move the first side gear 5 and the second side gear 7 to each other. Rotation and revolution about the rotation axis C according to the difference in rotation speed.

  The support portion 10 is formed on the cap 18 and supports a bottom receiving surface 23 that rotatably supports the bottom surface 21 of the bottom portion 20 of the pinion gear 9 by surface contact and a support shaft 22 of the bottom portion 20 of the pinion gear 9 that can rotate. And a support hole 24 that communicates the inside and outside of the case 2. The support portion 10 is configured to rotatably support the bottom portion 20 of the pinion gear 9.

  The bottom receiving surface 23 has a curved concave shape. The curvature radius of this curve is set to a value smaller than the distance from the rotation axis C of the case 2 to the bottom receiving surface 23. That is, the bottom receiving surface 23 has a concave shape in which the distance from the rotation axis C of the case 2 is shorter on the outer peripheral side than on the inner peripheral side.

  As shown in FIG. 5, two bottom bearing surface lubricating oil passages 25 are formed on the bottom bearing surface 23 of the support portion 10. The bottom bearing surface lubricating oil passage 25 is formed of a groove connecting the outer peripheral edge portion 23a and the inner peripheral edge portion 23b of the bottom receiving surface 23, and supports lubricating oil between the bottom surface 21 of the pinion gear 9 and the bottom receiving surface 23. Guide to 24. The bottom bearing surface lubricating oil passage 25 is formed from the end portion of the outer peripheral edge portion 23a of the bottom receiving surface 23 in the circumferential direction of the case 2 (indicated by an arrow in FIG. 5) from the case 2 of the inner peripheral edge portion 23b of the bottom receiving surface 23. Is formed in a spiral shape in the right rotation direction when viewed from the center side of the case 2.

  As shown in FIGS. 4 and 5, two support hole lubricating oil passages 26 are formed in the support hole 24 of the support portion 10. The support hole lubricating oil path 26 includes a groove connecting the inner peripheral edge 24 a of the support hole 24 and the outer peripheral edge 24 b of the case 2, and the support shaft 22 and the support hole 24 of the pinion gear 9. The lubricating oil between the two is guided to the outside of the case 2. The support hole lubricating oil passage 26 is continuous with the end portion of the bottom bearing surface lubricating oil passage 25 on the support hole 24 side, and is formed linearly along the axial direction of the support hole 24.

  Two peripheral lubricating oil passages 28 are formed inside the connecting portion 15 around the bottom receiving surface 23 of the support portion 10. The peripheral portion lubricating oil passage 28 is formed by a groove connecting the peripheral portion 27 and the outer peripheral edge portion 23 a of the bottom receiving surface 23, and guides the lubricating oil in the peripheral portion 27 to the bottom receiving surface 23. The peripheral lubricating oil passage 28 is continuous with the end of the bottom receiving surface lubricating oil passage 25 on the outer peripheral edge portion 23a side, and is widened from the bottom receiving surface 23 side along the circumferential direction of the case 2. . Further, the distance between the groove bottom of the peripheral lubricating oil passage 28 and the rotation axis C of the case 2 is longer on the bottom receiving surface 23 side and is shorter as it is farther from the bottom receiving surface 23.

  As shown in FIGS. 1 to 3, the openings 11 are formed at three locations between the three connecting portions 15. The opening 11 has a size that allows the first side gear 5 and the second side gear 7 to pass through the housing space 16 when the differential device 1 is assembled or disassembled.

Next, the operation of the differential device 1 will be described below. Here, the flow of the lubricating oil 35 will be mainly described.
As shown in FIG. 1, when the automobile travels, the driving force of the engine is transmitted to the drive pinion 4, and the drive pinion 4 rotates in the direction of the arrow 40. As the drive pinion 4 rotates, the ring gear 3 rotates in the direction of the arrow 41, and the case 2 rotates accordingly. At this time, the ring gear 3 scoops up the lubricating oil 35 stored in the housing 29.

  The lubricating oil 35 lifted up by the ring gear 3 reaches above the case 2. Part of the lubricating oil 35 that has reached the upper side of the case 2 flows down due to gravity, as indicated by an arrow 42, particularly when the engine is stopped or rotated at a low speed, and is supplied to the pinion gear 9 directly below through the opening 11 that opens upward. Is done. Further, the ring gear 3 rotates, and a part of the lubricant 35 that has been swept up is blown to the outer peripheral side of the ring gear 3 by centrifugal force as indicated by an arrow 43.

  Then, the lubricating oil 35 that has reached the meshing portion between the ring gear 3 and the drive pinion 4 is blown to the center side of the case 2 due to the pumping effect between the tooth surfaces of the ring gear 3 and the drive pinion 4 (in FIGS. 1 and 3). , Indicated by a white arrow). Since the opening 11 and the pinion gear 9 are opposed to each other across the rotation axis C of the case 2, the lubricating oil 35 blown from the meshing portion of the ring gear 3 and the drive pinion 4 is removed from the opening 11 of the case 2. It enters the inside of the case 2 without being interrupted by anything, and is directly supplied to the pinion gear 9 facing the opening 11 that has passed through.

  Lubricating oil 35 supplied to the pinion gear 9 from above or from the side reduces friction at the meshing portion between the first side gear 5 and the second side gear 7. Further, the lubricating oil 35 flows from the surface of the gear portion 19 of the pinion gear 9 to the surface of the bottom portion 20 by the centrifugal force of rotation of the case 2 and enters between the bottom surface 21 of the bottom portion 20 and the bottom receiving surface 23 of the support portion 10. .

  Here, the lubricating oil 35 inside the case 2 enters the peripheral lubricating oil passage 28 formed around the bottom receiving surface 23. The distance between the groove bottom of the peripheral lubricating oil passage 28 and the rotation axis C of the case 2 is longer on the bottom receiving surface 23 side and shorter as the distance from the bottom receiving surface 23 increases. The entered lubricating oil 35 is guided to the bottom receiving surface 23 by the rotating centrifugal force of the case 2. For this reason, the lubricating oil 35 adhering to the pinion gear 9 and the lubricating oil 35 around the bottom receiving surface 23 enter between the bottom surface 21 and the bottom receiving surface 23 due to the centrifugal force of the rotation of the case 2.

  Since the curvature radius of curvature of the bottom receiving surface 23 is smaller than the distance from the rotation axis C of the case 2 to the bottom receiving surface 23, the lubricating oil between the bottom surface 21 and the bottom receiving surface 23 is used. 35 flows toward the support hole 24 by the centrifugal force of the rotation of the case 2. Thereby, the lubricating oil 35 enters between the support shaft 22 and the support hole 24. Here, the bottom bearing surface lubricating oil passage 25 formed on the bottom receiving surface 23 is a groove that connects the outer peripheral edge portion 23a to the inner peripheral edge portion 23b of the bottom receiving surface 23. Also, the lubricating oil 35 is circulated through the support hole 24.

  Since the support hole 24 communicates the inside and outside of the case 2, the lubricating oil 35 between the support shaft 22 and the support hole 24 flows toward the outside of the case 2 due to the centrifugal force of the rotation of the case 2. Here, the support hole lubricating oil path 26 formed in the support hole 24 is a groove connecting the inner peripheral edge 24a of the support hole 24 to the case 2 and the outer peripheral edge 24b of the case 2, so The lubricating oil 35 is also circulated toward the outside of the case 2 through the hole lubricating oil passage 26.

  As described above, according to the differential device 1 according to the present embodiment, the pinion gear 9 is self-supported by fitting the support shaft 22 of the bottom portion 20 of the pinion gear 9 into the support hole 24 of the support portion 10. Thus, the conventional support protrusion for supporting the pinion gear 9 from the surroundings becomes unnecessary, and the lubricating oil 35 blown off from the drive pinion 4 enters the inside of the case 2 from the opening 11 without being blocked by the support protrusion, and the case 2 It reaches the bottom 20 of the pinion gear 9 due to the centrifugal force caused by the rotation of. For this reason, since the supply amount to the pinion gear 9 of the lubricating oil 35 blown from the drive pinion 4 to the center side of the case 2 can be increased, the reliability of preventing the seizure of the pinion gear 9 can be improved.

  Further, since three pinion gears 9 are provided every 120 degrees around the rotation axis C of the case 2, the lubricating oil 35 blown from the drive pinion 4 to the center side of the case 2 passes through the opening 11 to the case. 2 enters the pinion gear 9 located on the opposite side. Thereby, the flow volume of the lubricating oil 35 supplied to the pinion gear 9 can be increased.

  Further, since the support hole 24 communicates the inside and outside of the case 2, the lubricating oil 35 is discharged to the outside of the case 2 by centrifugal force due to the rotation of the case 2 without being stored in the support hole 24. For this reason, dust such as metal powder does not accumulate in the support hole 24 together with the lubricating oil 35 as in the case where the support hole 24 has a bottom, and the rotational resistance of the pinion gear 9 is increased by storing such dust. Can be prevented.

  Further, since the peripheral lubricating oil passage 28, the bottom receiving surface lubricating oil passage 25, and the support hole lubricating oil passage 26 are provided, the lubricating oil is supplied to the sliding contact portion between the bottom 20 of the pinion gear 9 and the support portion 10. The flow rate of the lubricating oil 35 can be increased, and the effect of increasing the amount is particularly high when the case 2 rotates at high speed. Thereby, the reliability to the seizure prevention of the pinion gear 9 can be improved.

  Further, since the bottom bearing surface lubricating oil passage 25 is formed in a spiral shape when viewed from the center side of the case 2, the bottom bearing surface lubricating oil passage 25 has a shape perpendicular to the rotation direction of the pinion gear 9. The resistance in the rotational direction of the pinion gear 9 between the bottom surface 21 and the bottom receiving surface 23 of the pinion gear 9 can be reduced. Thereby, while being able to rotate the pinion gear 9 smoothly, abrasion of the sliding contact part of the pinion gear 9 and the support part 10 can be suppressed.

  Further, since the gear portion 19 of the pinion gear 9 and the support shaft 22 are integrally formed, it is not necessary to use a pinion shaft that penetrates the gear portion 19 as in the prior art. Thereby, since it is not necessary to provide the through-hole for inserting a pinion shaft in the gear part 19, the pinion gear 9 can be reduced in size. Furthermore, since the opening 11 can be enlarged by reducing the size of the pinion gear 9, the amount of the lubricating oil 35 that passes through the opening 11 can be increased.

  Here, in the differential device 1 of the present embodiment described above, the bottom bearing surface lubricating oil passage 25 is provided in a spiral shape, but in the differential device according to the present invention, the number is limited to two. One may be sufficient. In this case, for example, as shown in FIG. 6, one end on the same side in the circumferential direction of the case 2 of the inner peripheral edge 23 b of the bottom receiving surface 23 from one end in the circumferential direction of the outer peripheral edge 23 a of the bottom receiving surface 23. The portion can be formed in a spiral shape that makes a round around the support hole 24 in the clockwise direction when viewed from the center side of the case 2.

  In addition, as shown by an imaginary line in FIG. 6, the case 2 is formed so that the outer peripheral edge 23 a of the bottom receiving surface 23 joins the bottom receiving surface lubricating oil passage 25 from the other end in the circumferential direction of the case 2. Further, a spiral branched lubricating oil passage 25a in the clockwise rotation direction as viewed from the center side may be further provided. Alternatively, the bottom bearing surface lubricating oil passage 25 is not limited to a spiral shape in the right rotation direction as viewed from the center side of the case 2, and may be a spiral shape in the left rotation direction.

  Further, in the above-described differential device 1 of the present embodiment, the bottom bearing surface lubricating oil passage 25 has a spiral shape. However, in the differential device according to the present invention, it is not limited to a spiral shape, for example, a linear shape or a curved line. It may be a shape. In this case, the bottom bearing surface lubricating oil passage 25 is linearly arranged radially from the inner peripheral edge portion 23b of the bottom receiving surface 23 to the outer peripheral edge portion 23a of the bottom receiving surface 23 as shown in FIG. Can do. According to this, since the work process at the time of formation of the cap 18 can be simplified, the component cost can be reduced. Alternatively, the bottom bearing surface lubricating oil passage 25 may have a curved shape that branches into two from the outer peripheral edge portion 23a of the bottom receiving surface 23 and reaches the inner peripheral edge portion 23b of the bottom receiving surface 23 as shown in FIG. Good.

  Moreover, in the differential device 1 of this Embodiment mentioned above, although the support hole lubricating oil path 26 is made into linear form, in the differential apparatus which concerns on this invention, it is not restricted to linear form, for example, helical shape or a curve It may be a shape. Furthermore, the peripheral lubricating oil passage 28 has a shape widened from the bottom receiving surface 23. However, in the differential according to the present invention, the shape is not limited to the widened shape, and for example, a linear shape, a spiral shape, or a curved shape. It may be.

  Further, the differential device 1 of the present embodiment described above includes the peripheral lubricating oil passage 28, the bottom bearing surface lubricating oil passage 25, and the support hole lubricating oil passage 26, but the differential according to the present invention. The apparatus is not limited to including all of the peripheral portion lubricating oil passage 28, the bottom bearing surface lubricating oil passage 25, and the support hole lubricating oil passage 26. For example, the peripheral portion lubricating oil passage 28 and the bottom receiving surface lubricating oil passage 25 are provided. And one or two of the support hole lubricating oil paths 26 may be provided, or may not be provided at all.

  Further, in the differential device 1 of the present embodiment described above, the case 2 is integrally formed. However, the differential device according to the present invention is not limited to the integrally formed, and can be divided, for example. It may be good. In this case, for example, as shown in FIG. 9, the case 2 can be divided into a first cylindrical portion-side half 30 and a second cylindrical portion-side half 31.

  Here, the first cylindrical part-side half 30 includes the first cylindrical part 12, the flange part 14, the connecting part 15, and the fixed ring part formed on the second cylindrical part 13 side of the connecting part 15. 32. The second cylindrical portion-side half 31 includes a second cylindrical portion 13 and a fixed flange portion 33 formed on the first cylindrical portion 12 side of the second cylindrical portion 13. The fixing ring portion 32 and the fixing flange portion 33 are fixed by bolts 34. By fixing the fixing ring portion 32 and the fixing flange portion 33, the first cylindrical portion side half 30 and the second cylindrical portion side half 31 are integrated to form the case 2. According to this case 2, the first side gear 5 and the second side gear 7 can be easily put in and out of the housing space 16 of the case 2.

  Further, in the differential device 1 of the present embodiment described above, three pinion gears 9 are provided. However, in the differential device according to the present invention, the number is not limited to three, and may be two or four, for example. Good. In the case of two, for example, as shown in FIG. 10, the pinion gear 9 is provided every 180 degrees around the rotation axis C of the case 2. According to this, since the number of parts can be reduced, the part cost can be reduced.

  Moreover, in the differential device 1 of this Embodiment mentioned above, although the gear part 19 and the support shaft 22 of the pinion gear 9 are integrally formed, in the differential device based on this invention, it is not restricted to integral formation. For example, a shaft hole may be formed in the gear portion 19, and a support shaft made of another member may be press-fitted into the shaft hole and integrated.

  As described above, the differential device according to the present invention is useful for all differential devices suitable for increasing the supply amount of lubricating oil blown from the drive pinion to the center side of the case to the pinion gear.

DESCRIPTION OF SYMBOLS 1 Differential device 2 Case 3 Ring gear 4 Drive pinion 5 1st side gear 6 1st drive shaft 7 2nd side gear 8 2nd drive shaft 9 Pinion gear 10 Support part 11 Opening part 19 Gear part 21 Bottom face 22 Support shaft 23 Bottom receiving surface 23a Outer peripheral edge portion 23b of the bottom receiving surface Inner peripheral edge portion 24 of the bottom receiving surface Support hole 24a Peripheral portion 24b on the inner side of the support hole Peripheral portion 25 on the outer side of the support hole Bottom support surface lubricating oil passage 26 Support hole Lubricating oil passage 27 Surrounding portion 28 Surrounding portion lubricating oil passage 35 Lubricating oil C Case rotation shaft

Claims (9)

A rotatable case, a ring gear made of a hypoid gear fixed coaxially to the case and at least partially immersed in lubricating oil to lift up the lubricating oil by rotation, and a drive pinion made of a hypoid pinion meshing with the ring gear; A first side gear comprising a bevel gear housed in the case and coaxially supported with the ring gear and rotatably supported by the case; and a first drive shaft coupled to the first side gear and integrally rotated. A second side gear comprising a bevel gear housed in the case and coaxially opposed to the first side gear and rotatably supported by the case; and connected to the second side gear and integrally rotated. A second drive shaft; and the first side gear housed in the case And two or more pinion gears comprising bevel gears having a gear portion meshing with the second side gear, and a support portion that is formed in the case and pivots along with the rotation of the ring gear and rotatably supports the pinion gear. In addition, the differential device includes an opening that is formed between the support portions and communicates between the inside and outside of the case so that the lubricating oil can be supplied to the inside of the case from the outside of the case.
The pinion gear has a bottom surface of the gear portion and a support shaft that is coaxial with the rotation axis of the gear portion and protrudes from the center of the bottom surface,
The support portion includes a bottom receiving surface that rotatably supports the bottom surface of the pinion gear by surface contact, and a support hole that rotatably supports the support shaft of the pinion gear and communicates the inside and outside of the case. A differential device characterized by.   The differential device according to claim 1, wherein the bottom receiving surface has a curved concave shape with a radius of curvature smaller than a distance from a rotation axis of the case to the bottom receiving surface.   The lubricating oil is formed on the bottom receiving surface and connects an outer peripheral edge portion and an inner peripheral edge portion of the bottom receiving surface to guide the lubricating oil between the bottom surface of the pinion gear and the bottom receiving surface to the support hole. The differential device according to claim 1, further comprising a bottom receiving surface lubricating oil passage formed of a groove that forms a groove.   The support hole is formed between the support hole of the pinion gear and the support hole by connecting a peripheral part of the support hole inside the case and a peripheral part of the case outside. The differential device according to any one of claims 1 to 3, further comprising a support hole lubricating oil path including a groove for guiding the lubricating oil to the outside of the case.   A peripheral lubricating oil path comprising a groove for connecting the peripheral portion of the bottom receiving surface and the outer peripheral edge of the bottom receiving surface and guiding the lubricating oil of the peripheral portion to the bottom receiving surface is provided. The differential device according to any one of claims 1 to 4.   6. The differential device according to claim 1, wherein at least one of the bottom bearing surface lubricating oil path and the support hole lubricating oil path is spiral.   The at least one of the bottom bearing surface lubricating oil path, the support hole lubricating oil path, and the peripheral lubricating oil path is linear. The differential device described in 1.   8. The pinion gear according to claim 1, wherein three pinion gears are provided every 120 degrees centering on rotation axes of the first side gear and the second side gear. 9. Differential.   8. The pinion gear according to claim 1, wherein two pinion gears are provided every 180 degrees around the rotation shafts of the first side gear and the second side gear. 9. Differential.

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