JP2012145206A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device that can increase supply of a lubricant to a slidable part between a pinion gear and a pinion shaft in high-speed rotation of a case.SOLUTION: The differential device 1 includes: a pair of side gears 5 that are housed in a rotatable case 2; three pinion gears 9; the pinion shaft 10 that rotatably supports the pinion gears 9; the pinion shaft 10 that rotatably supports the pinion gears 9; the slidable part 11 between the pinion gears 9 and the pinion shaft 10; a supporting part 12 that supports the pinion shaft 10; and an opening 13 that can supply the lubricant 18 from outside the case 2 into the case 2 in communication with inside and outside the case 2. The device includes a lubricant storage part 23 for containing the lubricant 18, that continues in a rotary shaft C side of the case 2 of a gap of the slidable part 11 in either the pinion gear 9 or the pinion shaft 10, and is composed of a space opening toward the rotary shaft C side 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 sliding portion between a pinion gear and a pinion shaft during high-speed rotation of a case. .

  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.

  As shown in FIG. 9, this type of 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 pinion composed of a hypoid pinion meshing with the ring gear 103. 104, a side gear 105 made up of a pair of bevel gears housed in the case 101 and rotatable independently of the case 101, a drive shaft 106 that rotates integrally with the side gear 105, and a pair of bevel gears meshed with the side gear 105. A pinion gear 107, a pinion shaft 108 that rotatably supports the two pinion gears 107, a pair of support portions 109 that are formed in the case 102 and support the pinion shaft 108, and a support portion 109 that penetrates the pinion shaft 108. Secure to It includes a constant pin 110 and an opening 111 that communicates the inside and outside of the space of the case 101 while being formed between the support portion 109 (e.g., see Patent Document 1).

  The pinion gear 107 is formed so that the upper surface 107a, which is the surface on the rotation axis C side of the case 101, is planar. An engagement hole 107c is formed from the top surface 107a to the bottom surface 107b of the pinion gear 107 so as to pass through the central portion along the rotation axis. Necessary minimum chamfering is performed on the peripheral portions of the engagement hole 107c on the upper surface 107a side and the bottom surface 107b side. The pinion gear 107 is rotatably supported by fitting the engagement hole 107 c to the pinion shaft 108.

  By the way, in the lubricating oil supply path to the inside of the case 101 of the differential device 100 of this type, the path that was conventionally considered to have the largest supply amount of lubricating oil is the upper part of the ring gear 103 due to the rotation of the ring gear 103. It was a path in which the lubricating oil that had been swept up to the point of flowed down from above the opening 111 that opened upward, passed through the opening 111, and supplied to the inside of the case 101.

  On the other hand, as a result of extensive research conducted 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 (in FIG. It is found that the supply amount is larger in the route that passes through the opening 111 and is supplied into the case 101 from the side. The reason why the lubricating oil is blown sideways from the meshing portion of the ring gear 103 and the drive pinion 104 is that the tooth surfaces of the ring gear 103 and the drive pinion 104 are close to each other and slip at the meshing portion of the ring gear 103 and the drive pinion 104. This is presumably because the pumping effect of trying to push the lubricating oil to the center side of the ring gear 103 occurs.

  Therefore, according to the differential device 100 described above, the lubricating oil that has been lifted up by the ring gear 103 is blown to the center side of the case 101 by the drive pinion 104 that meshes with the ring gear 103 and passes through the opening 111. Part is supplied to the pinion shaft 108 and part is supplied to the pinion gear 107. Then, the lubricating oil supplied to the pinion shaft 108 flows to both ends on the surface of the pinion shaft 108 due to the centrifugal force of rotation of the case 101, and joins the lubricating oil supplied directly to the pinion gear 107. The engagement hole 107c enters between the pinion shaft 108 and the engagement hole 107c from the periphery on the upper surface 107a side by capillary action and centrifugal force. Thereby, the lubricating oil is supplied to the sliding portion 112 between the pinion gear 107 and the pinion shaft 108, and the frictional resistance of the sliding portion 112 is reduced by the lubricating oil.

  Here, when the case 101 rotates at a low speed, the centrifugal force in the ring gear 103 is small, and a relatively large amount of lubricating oil adheres to the ring gear 103, so the amount of lubricating oil supplied to the pinion shaft 108 is large. For this reason, the entire amount of the lubricating oil supplied to the upper surface 107a of the pinion gear 107 through the pinion shaft 108 cannot enter the sliding portion 112, and a part thereof flows from the periphery of the upper surface 107a to the tooth surface of the pinion gear 107. . On the other hand, when the case 101 rotates at a high speed, a large amount of lubricating oil is blown away from the ring gear 103 by centrifugal force, so that the amount of lubricating oil supplied to the pinion gear 107 is reduced.

  Further, in recent years, not a structure in which two pinion gears 107 are provided on one pinion shaft 108 as described above, but a structure in which one pinion gear 107 is provided on each of two or three short pinion shafts 113. The differential device 100 is becoming widespread. According to such a differential device 100, the lubricating oil lifted up 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 and passes through the opening 111, and a part thereof It is supplied to the upper surface 107a of the pinion gear 107.

  Then, the lubricating oil supplied to the upper surface 107a of the pinion gear 107 enters between the pinion shaft 113 and the engagement hole 107c from the peripheral portion on the upper surface 107a side of the engagement hole 107c by capillary action and centrifugal force. Thereby, the lubricating oil is supplied to the sliding portion 112 between the pinion gear 107 and the pinion shaft 113, and the frictional resistance of the sliding portion 112 is reduced by the lubricating oil.

  Also in this case, when the case 101 rotates at a low speed, a relatively large amount of lubricating oil adheres to the ring gear 103, and therefore the amount of lubricating oil supplied to the upper surface 107a of the pinion gear 107 is large. For this reason, the entire amount of the lubricating oil supplied to the upper surface 107a of the pinion gear 107 cannot enter the sliding portion 112, and a part of the lubricating oil flows from the periphery of the upper surface 107a to the tooth surface of the pinion gear 107. On the other hand, when the case 101 rotates at a high speed, a large amount of lubricating oil is blown away from the ring gear 103 by centrifugal force, so that the amount of lubricating oil supplied to the pinion gear 107 is reduced.

  In view of such a situation, the inventor of the present application pays attention to the lubricating oil that is supplied in a large amount to the upper surface 107a of the pinion gear 107 and cannot enter the sliding portion 112 when the case 101 rotates at low speed, and rotates the lubricating oil at low speed. It is sometimes held temporarily, and when the supply amount of the lubricating oil to the sliding portion 112 is reduced by the high speed rotation of the case 101, the lubricating oil held at the low speed rotation is supplied to the sliding portion 112. I came up with the mechanism.

JP 2010-38223 A

  However, in the configuration of the differential device 100 as described above, since the necessary minimum chamfering is performed on the peripheral portion on the upper surface 107 a side of the engagement hole 107 c of the pinion gear 107, the upper surface of the pinion gear 107. No lubricating oil is retained at 107a. For this reason, even if the case 101 rotates at a high speed and the amount of lubricating oil supplied to the inside of the case 101 decreases, the lubricating oil cannot be replenished, and the amount of lubricating oil supplied to the upper surface 107a of the pinion gear 107 is reduced. As a result, the sliding portion 112 may not be supplied with a sufficient amount of lubricating oil. When the differential device 100 is operated for a long time in a state where the sliding portion 112 has a small amount of lubricating oil, there is a problem that the sliding portion 112 may be seized in some cases.

  The present invention has been made to solve the above-described conventional problems, and in particular, a differential device capable of increasing the amount of lubricating oil supplied to the sliding portion between the pinion gear and the pinion shaft when the case rotates at a high speed. The purpose is to provide.

  In order to achieve the above object, the differential device according to the present invention includes: (1) a case rotatable around a rotation axis; and the case fixed to the case coaxially and at least a part of which is immersed in lubricating oil and rotated to A ring gear composed of a hypoid gear that lifts up lubricating oil, a drive pinion composed of a hypoid pinion that meshes with the ring gear, and a bevel gear that is housed in the case and coaxially supported by the case and rotatably supported by the case. 1 side gear, a first drive shaft connected to the first side gear and rotating integrally therewith, and housed in the case and coaxially opposed to the first side gear and rotatably supported by the case. A second side gear comprising a bevel gear and a second driver coupled to the second side gear and rotating integrally therewith. And two or more pinion gears, each of which is comprised of a bevel gear, which is accommodated in the case and meshes with the first side gear and the second side gear, and has a support hole penetrating the central portion along the rotation axis; A pinion shaft that fits in the support hole of the pinion gear and rotatably supports the pinion gear, and a sliding portion that includes a gap between the inner peripheral surface of the support hole of the pinion gear and the outer peripheral surface of the pinion shaft. And a support portion that is formed in the case and supports the pinion shaft, and is formed between the support portions and communicates with the inside and outside of the case from the outside of the case to the inside of the case. And a differential having an opening that allows oil to be supplied, at least the pinion gear and the pinion shaft. On the other hand, a lubricating oil reservoir that is formed of a space that is continuous to the rotating shaft side of the case and that opens toward the rotating shaft side of the case and that can store the lubricating oil. It is characterized by providing.

  With this configuration, when the ring gear rotates at a low speed, the lubricating oil is swept up by the ring gear, and a large amount of lubricating oil is supplied into the case from above or from the side. Part of the lubricating oil supplied to the inside of the case is supplied directly to the pinion gear, or travels along the surface of the pinion shaft and enters the lubricating oil storage part that is a space that opens toward the rotating shaft side of the case. . A part of the lubricating oil that has entered the lubricating oil reservoir is held in the lubricating oil reservoir by centrifugal force and surface tension due to rotation of the case. Further, since the space of the lubricating oil reservoir is continuous with the gap of the sliding portion between the pinion gear and the pinion shaft, the other part of the lubricating oil that has entered the lubricating oil reservoir is centrifuged by the rotation of the case. It enters the sliding part between the pinion gear and the pinion shaft by force and capillary action.

  When the ring gear is rotated at a high speed, the lubricating oil swept up by the ring gear is blown away by centrifugal force, so that the lubricating oil supplied from the outside of the case to the inside of the case is reduced, but the lubricating oil is stored. Lubricating oil held in the portion continues to be supplied to the sliding portion between the pinion gear and the pinion shaft by centrifugal force and capillary action due to rotation of the case. As a result, a sufficient amount of lubricating oil can be supplied to the sliding portion between the pinion gear and the pinion shaft even during high-speed rotation of the ring gear, and reliability for preventing seizure between the pinion gear and the pinion shaft can be achieved. Can be improved.

  In the differential device according to the above (1), (2) the lubricating oil reservoir is located on the rotation shaft side of the case of the pinion gear from the periphery on the rotation shaft side of the case on the inner peripheral surface of the support hole. It is preferable to be surrounded by a peripheral wall continuous to the end face.

  With this configuration, since the peripheral wall is provided on the pinion gear, the diameter is larger than when the peripheral wall is provided on the pinion shaft. Therefore, if the peripheral wall has the same width, the volume of the lubricating oil reservoir can be increased. Therefore, it is possible to increase the amount of the lubricating oil retained in the lubricating oil reservoir.

  In the differential device according to the above (1) or (2), (3) the pinion shaft is fixed so as not to rotate with respect to the support portion, and the end surface of the pinion shaft on the rotating shaft side of the case is The pinion gear is positioned on the same plane with respect to the end surface of the case on the rotating shaft side or is positioned on the outer peripheral side of the case, and the lubricating oil reservoir is the case on the outer peripheral surface of the pinion shaft. It is preferable that it is surrounded by the surrounding wall which continues from the periphery of the rotating shaft side to the end surface of the pinion shaft on the rotating shaft side of the case.

  With this configuration, the pinion shaft does not rotate with respect to the support portion even when the pinion gear rotates, so that the lubricating oil retained in the lubricating oil storage portion is blown away by the centrifugal force due to the rotation of the pinion gear. It can suppress and can improve the lubricating oil retention of a lubricating oil storage part.

  In the differential device described in (2) or (3) above, (4) it is preferable that the peripheral wall has a planar shape inclined with respect to the rotation axis of the pinion gear. With this configuration, when centrifugal force due to rotation of the case is given to the lubricating oil held in the lubricating oil reservoir, the case of the sliding portion between the pinion gear and the pinion shaft is caused by the planar peripheral wall where the lubricating oil is inclined. It is guided to the rotating shaft side and further supplied to the sliding portion between the pinion gear and the pinion shaft by centrifugal force and capillary action. Therefore, the lubricating oil held in the lubricating oil reservoir is smoothly supplied to the sliding portion between the pinion gear and the pinion shaft.

  In the differential device described in (1) to (4) above, (5) it is preferable that the outer peripheral portion of the pinion shaft is provided with a lubricating oil groove capable of flowing lubricating oil in the axial direction. With this configuration, the lubricating oil supplied from the lubricating oil reservoir to the sliding portion between the pinion gear and the pinion shaft is guided by the lubricating oil groove and flows to the outer peripheral side of the case. As a result, more lubricating oil flows through the sliding part between the pinion gear and the pinion shaft than when there is no lubricating oil groove, improving the reliability to prevent seizure between the pinion gear and the pinion shaft. can do.

  In the differential device described in (1) to (5) above, (6) 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 and pinion shaft located on the opposite side. Thereby, the flow rate of the lubricating oil supplied to the pinion gear and the pinion shaft can be increased, and the reliability for preventing seizure between the pinion gear and the pinion shaft 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. 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 according to (1) to (5) above, (7) 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 lubricating oil reservoir is provided on the rotating shaft side of the case of the sliding portion of the pinion gear and the pinion shaft, the lubricating oil retained in the lubricating oil reservoir is separated from the pinion gear and the pinion shaft. By supplying to the sliding portion, it is possible to provide a differential device that can increase the amount of lubricant supplied to the sliding portion between the pinion gear and the pinion shaft.

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. BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view which shows the example of the pinion gear and pinion shaft of the differential device which concerns on embodiment of this invention, and the pinion shaft which varied length, (a) is the differential device which concerns on embodiment of this invention The pinion gear and the pinion shaft of the pinion shaft, (b) is the case where the end surface of the pinion shaft case on the rotating shaft side is flush with the end surface of the pinion gear case on the rotating shaft side, (c) is the rotating shaft side of the pinion shaft case When the end surface of the pinion gear is between the end surface on the rotating shaft side of the case of the pinion gear and the peripheral edge on the rotating shaft side of the case of the support hole, FIG. The case where it is dented rather than the periphery of the rotating shaft side of each is shown. It is a longitudinal cross-sectional view which shows the example of the surrounding wall of the lubricating oil storage part of the differential device which concerns on embodiment of this invention, and the surrounding wall of another shape, (a) of the differential device which concerns on embodiment of this invention A peripheral wall of the lubricating oil reservoir, (b) shows an L-shaped peripheral wall, (c) shows an arc-shaped peripheral wall protruding downward, and (d) shows an arc-shaped peripheral wall protruding upward. It is a longitudinal cross-sectional view which shows the example of the pinion gear and the pinion shaft which varied the shape of the differential gear which concerns on embodiment of this invention, (a) is the lubricating oil storage part of the surrounding wall of a cross-hatched shape in the middle of a pinion shaft (B) shows that the end surface of the pinion shaft case on the rotating shaft side is flush with the end surface of the pinion gear case on the rotating shaft side and the end surface of the pinion shaft case on the rotating shaft side has an oblique cross-sectional shape. In the case of having a lubricating oil reservoir in the peripheral wall, (c) shows that the end surface of the pinion shaft case on the rotating shaft side is recessed from the end surface of the pinion gear case on the rotating shaft side and the end surface of the pinion shaft case on the rotating shaft side In the case of having a lubricating oil reservoir with a peripheral wall having an oblique cross section, (d) having a lubricating oil reservoir having a peripheral wall having a circular arc in the middle of the pinion shaft, (e) The end surface of the pinion shaft case on the rotating shaft side is flush with the end surface of the pinion gear case on the rotating shaft side, and the end surface on the rotating shaft side of the pinion shaft case has a lubricating oil reservoir with an arc-shaped peripheral wall. In the case, (f) shows the case where both the pinion gear and the pinion shaft have a lubricating oil reservoir with a peripheral wall having an oblique cross section. It is a longitudinal cross-sectional view which shows the example of the lubricating oil groove of a different shape provided in the outer peripheral part of the pinion shaft of the differential gear which concerns on embodiment of this invention, (a) is lubrication which consists of a spline parallel to an axial direction When it is an oil groove, (b) shows the case where it is a lubricating oil groove consisting of a spiral spline. 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.

  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 case 2 that can rotate around a rotation axis C, a ring gear 3 that includes a hypoid gear fixed to the case 2, and a hypoid pinion that meshes with the ring gear 3. A drive pinion 4, a first side gear 5 made up of a bevel gear housed in the case 2, a first drive shaft 6 connected to the first side gear 5, and a bevel gear housed in the case 2. Second side gear 7, second drive shaft 8 coupled to second side gear 7, three pinion gears 9, three pinion shafts 10, and sliding portion 11 of pinion gear 9 and pinion shaft 10 And three support portions 12 and an opening portion 13 formed between the support portions 12 and communicating with the inside and outside of the case 2.
The differential 1 is housed in a housing 30 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 14, a second cylindrical portion 15, and a flange portion 16 formed on the outer peripheral side of the first cylindrical portion 14 and is integrally formed.

  The support portion 12 is provided every 120 degrees in the circumferential direction of the case 2, and connects the first cylindrical portion 14 and the second cylindrical portion 15 so as to be coaxial with the rotation axis C. Yes. The support portion 12 revolves around the rotation axis C as the case 2 rotates. Further, the pinion gear 9 and the opening 13 are opposed to each other with the rotation axis C of the case 2 interposed therebetween. A space surrounded by the first cylindrical portion 14, the support portion 12, and the second cylindrical portion 15 is an accommodation space 17.

  On the second cylindrical portion 15 side of the flange portion 16, the ring gear 3 having the rotation axis C as a rotation axis is fixed by screwing. The ring gear 3 is installed so that a part of the lower part is immersed in the lubricating oil 18 stored in the bottom of the housing 30. The ring gear 3 is adapted to lift up the lubricating oil 18 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 14. A second drive shaft 8 is rotatably supported by the second cylindrical portion 15. The first drive shaft 6 and the second drive shaft 8 have the rotation axis C as the rotation axis.

  The accommodation space 17 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 support portion 12 and is provided every 120 degrees around the rotation axes of the first side gear 5 and the second side gear 7. Further, the pinion gear 9 has a support hole 19 that passes through the central portion along the rotation axis of the pinion gear 9.

  The pinion gear 9 is rotatably supported by the pinion shaft 10 by fitting the support hole 19 to the pinion shaft 10. The pinion shaft 10 has a cylindrical and smooth outer peripheral surface, and is fixed through the support portion 12. The pinion shaft 10 is fixed so as not to rotate or drop off with respect to the support portion 12 by a fixing pin 20 penetrating the pinion shaft 10 in parallel with the rotation axis C of the case 2. 4A, the bottom surface 9a of the pinion gear 9 is rotatably supported by being in surface contact with the inner side surface 11a of the support portion 12. As shown in FIG. Further, the end surface 10 a of the pinion shaft 10 on the rotating shaft C side of the case 2 protrudes from the end surface 9 b of the pinion gear 9 on the rotating shaft C side.

  As shown in FIGS. 1 to 3, 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 sliding portion 11 is formed by a minute gap between the inner peripheral surface of the support hole 19 of the pinion gear 9 and the outer peripheral surface of the pinion shaft 10. The support hole 19 of the pinion gear 9 is continuous with the rotation axis C side of the case 2 in the gap of the sliding portion 11 and opens toward the rotation axis C side of the case 2. Lubricating oil storage part 23 consisting of a space is formed. The lubricating oil reservoir 23 can accommodate and hold the lubricating oil 18.

The lubricating oil reservoir 23 is surrounded by a peripheral wall 22 that continues from the periphery of the inner peripheral surface of the support hole 19 on the rotation axis C side of the case 2 to the end surface 9 b of the pinion gear 9. The peripheral wall 22 has a planar shape inclined about 45 degrees with respect to the rotation axis of the pinion gear 9. For this reason, the lubricating oil reservoir 23 has a shape opened to the rotating shaft C side of the case 2 of the pinion gear 9.
The differential device 1 according to the present embodiment includes a pinion gear 9, a pinion shaft 10, a sliding part 11, and a lubricating oil storage part 23.

  The openings 13 are formed at three locations between the three support portions 12. The opening 13 has a size that allows the first side gear 5 and the second side gear 7 to pass through the housing space 17 when the differential device 1 is assembled or disassembled. Further, the opening 13 is configured so that the lubricating oil 18 can be supplied from the outside of the case 2 to the inside of the case 2.

Next, the operation of the differential device 1 will be described below. Here, the flow of the lubricating oil 18 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 18 stored in the housing 30.

  The lubricating oil 18 lifted up by the ring gear 3 reaches above the case 2. Part of the lubricating oil 18 that has reached the upper side of the case 2 flows down by gravity as indicated by an arrow 42, particularly when the engine is stopped or rotated at a low speed, passes through the opening 13 that opens upward, and enters the accommodation space 17, It is supplied to the pinion gear 9 and the pinion shaft 10 directly below. Further, the ring gear 3 is rotated, and a part of the lubricating oil 18 that is swept up is blown to the outer peripheral side of the ring gear 3 by centrifugal force as indicated by an arrow 43 and supplied to a bearing (not shown) of the drive pinion 4. .

  Then, the lubricating oil 18 that has reached the meshing portion between the ring gear 3 and the drive pinion 4 without being blown from the ring gear 3 is blown to the center side of the case 2 by the pumping effect of the tooth surfaces of the ring gear 3 and the drive pinion 4 ( 1 and 3 are indicated by white arrows). Since the opening 13 and the pinion gear 9 are opposed to each other across the rotation axis C of the case 2, the lubricating oil 18 blown from the meshing portion of the ring gear 3 and the drive pinion 4 is removed from the opening 13 of the case 2. It enters the accommodation space 17 of the case 2 without being interrupted by anything, and is directly supplied to the pinion gear 9 and the pinion shaft 10 facing the opening 13 that has passed through.

  Here, when the ring gear 3 rotates at a low speed, the amount of the lubricating oil 18 that is blown to the outer peripheral side by the centrifugal force of the ring gear 3 is small, and a large amount of the lubricating oil 18 is supplied into the case 2 from above or from the side. The

  A part of the lubricating oil 18 supplied to the pinion gear 9 and the pinion shaft 10 from above or from the side of the case 2 enters the lubricating oil reservoir 23 and is held by centrifugal force and surface tension due to rotation of the case 2. A part of the lubricating oil 18 held in the lubricating oil reservoir 23 enters the sliding portion 11 between the pinion gear 9 and the pinion shaft 10 due to the centrifugal force and capillary action caused by the rotation of the case 2. Thereby, seizure prevention with the pinion gear 9 and the pinion shaft 10 is achieved. The lubricating oil 18 that has entered the sliding portion 11 is discharged from the outer peripheral side of the case 2 in the support hole 19 by the centrifugal force of the rotation of the case 2.

  Further, the other part of the lubricating oil 18 supplied to the pinion gear 9 and the pinion shaft 10 does not enter the lubricating oil reservoir 23, but from the peripheral portion of the end surface 9 b of the case 2 of the pinion gear 9 on the rotating shaft C side. It flows to the tooth surface of 9. The lubricating oil 18 that has flowed to the tooth surface of the pinion gear 9 reduces friction at the meshing portion between the first side gear 5 and the second side gear 7. Further, the lubricating oil 18 flows from the tooth surface of the pinion gear 9 to the bottom surface 9 a and is supplied between the inner surface 11 a of the support portion 12 and reduces friction between the pinion gear 9 and the support portion 12.

  When the ring gear 3 is rotated at a high speed, the amount of the lubricating oil 18 lifted up by the ring gear 3 is increased by centrifugal force, so that the lubricating oil 18 is supplied from the outside of the case 2 to the housing space 17 of the case 2. Lubricating oil 18 decreases. On the other hand, the lubricating oil 18 held in the lubricating oil reservoir 23 continues to be supplied to the sliding portion 11 between the pinion gear 9 and the pinion shaft 10 due to the centrifugal force and capillary action of the case 2. Thereby, even when the ring gear 3 is rotating at a high speed, a sufficient amount of lubricating oil 18 can be supplied between the pinion gear 9 and the pinion shaft 10.

  As described above, according to the differential device 1 according to the present embodiment, a large amount of lubricating oil 18 is supplied from the outside of the case 2 to the inside of the case 2 when the ring gear 3 rotates at a low speed, and enters the lubricating oil reservoir 23. Even if the lubricating oil 18 is held and the lubricating oil 18 supplied from the outside of the case 2 decreases when the ring gear 3 rotates at a high speed, the lubricating oil 18 held in the lubricating oil reservoir 23 remains in the pinion gear 9 and the pinion shaft. It continues to be supplied to the sliding part 11 between 10. Thereby, even when the ring gear 3 rotates at a high speed, a sufficient amount of lubricating oil 18 can be supplied to the sliding portion 11 between the pinion gear 9 and the pinion shaft 10, and the pinion gear 9 and the pinion shaft 10 can be connected to each other. Reliability for preventing burn-in can be improved.

  Further, since the three pinion gears 9 are provided every 120 degrees around the rotation axis C of the case 2, the lubricating oil 18 blown from the drive pinion 4 to the center side of the case 2 passes through the opening 13 to the case. When it enters the second accommodating space 17, it is supplied to the pinion gear 9 and the pinion shaft 10 located on the opposite side. Thereby, the flow volume of the lubricating oil 18 supplied to the pinion gear 9 and the pinion shaft 10 can be increased.

  Moreover, since the lubricating oil storage part 23 is provided in the pinion gear 9, since a diameter becomes large compared with the case where the lubricating oil storage part 23 is provided in the pinion shaft 10, if it is the lubricating oil storage part 23 of the same width | variety The volume of the lubricating oil reservoir 23 can be increased. Therefore, the amount of the lubricating oil 18 held in the lubricating oil storage unit 23 can be increased.

  Further, since the peripheral wall 22 has a planar shape inclined with respect to the rotation axis of the pinion gear 9, when the centrifugal force due to the rotation of the case 2 is applied to the lubricating oil 18 held in the lubricating oil reservoir 23, the lubricating oil 18 is guided to the rotating shaft side of the case 2 of the sliding portion 11 between the pinion gear 9 and the pinion shaft 10 by the inclined flat peripheral wall 22 and further supplied to the sliding portion 11 by centrifugal force and capillary action. . Therefore, the lubricating oil 18 held in the lubricating oil reservoir 23 is smoothly supplied to the sliding portion 11 between the pinion gear 9 and the pinion shaft 10.

  Here, in the differential device 1 of the present embodiment described above, as shown in FIG. 4A, the end surface 10a of the pinion shaft 10 on the side of the rotation axis C of the case 2 is the rotation axis of the case 2 of the pinion gear 9. Although projecting from the end surface 9b on the C side, the differential device according to the present invention is not limited to this. For example, as shown in FIG. 4B, the rotation shaft C side of the case 2 of the pinion shaft 10 is provided. The end surface 10a can be flush with the end surface 9b of the case 2 of the pinion gear 9 on the rotating shaft C side. 4C, the end surface 10a on the rotation axis C side of the case 2 of the pinion shaft 10 is the rotation of the end surface 9b on the rotation axis C side of the case 2 of the pinion gear 9 and the rotation of the case 2 of the support hole 19. It can be between the periphery on the axis C side. Alternatively, as illustrated in FIG. 4D, the end surface 10 a on the rotation axis C side of the case 2 of the pinion shaft 10 can be recessed from the periphery of the support hole 19 on the rotation axis C side of the case 2.

  Further, in the above-described differential device 1 of the present embodiment, as shown in FIG. 5A, the peripheral wall 22 of the lubricating oil reservoir 23 is planar with an inclination of about 45 degrees with respect to the rotation axis of the pinion gear 9. However, in the differential device according to the present invention, the peripheral wall 22 is not limited to a planar shape inclined by 45 degrees, and may be another angle such as 30 degrees or 60 degrees. Further, the peripheral wall 22 is not limited to an inclined planar shape, for example, as shown in FIG. 5 (b), it may have an L-shaped cross section, or it may have a circular arc shape protruding downward as shown in FIG. 5 (c). As shown in FIG. 5 (d), it may have a circular arc shape protruding upward.

  Furthermore, in the differential device 1 of the present embodiment described above, the lubricating oil reservoir 23 is provided only in the pinion gear 9. However, in the differential device according to the present invention, the lubricating oil reservoir 23 is provided in the pinion gear 9. However, the lubricating oil reservoir 23 may be provided only on the pinion shaft 10. According to this, since the pinion shaft 10 does not rotate with respect to the support portion 12 even when the pinion gear 9 rotates, the lubricating oil 18 held in the lubricating oil reservoir 23 is surrounded by the centrifugal force generated by the rotation of the pinion gear 9. Can be suppressed, and the lubricating oil retention of the lubricating oil reservoir 23 can be improved.

  In this case, for example, as shown in FIG. 6A, a lubricating oil reservoir 23 whose peripheral wall 22 has an inclined surface can be provided in the middle of the pinion shaft 10. 6B, the end surface 10a of the pinion shaft 10 on the rotating shaft C side of the case 2 is on the same plane as the end surface 9b of the pinion gear 9 on the rotating shaft C side of the case 2, and the pinion shaft A lubricating oil reservoir 23 having a peripheral wall 22 having an inclined surface can be provided at the end of the ten cases 2 on the rotation axis C side.

  Further, in this case, as shown in FIG. 6C, the end surface 10 a of the pinion shaft 10 on the rotation axis C side of the case 2 is recessed from the end surface 9 b of the case 2 of the pinion gear 9 on the rotation axis C side. A lubricating oil reservoir 23 having a sloped peripheral wall 22 can be provided at the end of the shaft 10 on the rotating shaft C side of the case 2. Further, as shown in FIG. 6 (d), a lubricating oil reservoir 23 having a circular arc shape in which the peripheral wall 22 is recessed can be provided in the middle of the pinion shaft 10. In this case, as shown in FIG. 6E, the end surface 10a of the pinion shaft 10 on the rotating shaft C side of the case 2 is flush with the end surface 9b of the pinion gear 9 on the rotating shaft C side. The lubricating oil reservoir 23 having a circular arc shape in which the peripheral wall 22 protrudes can be provided at the end of the pinion shaft 10 on the rotation axis C side of the case 2.

  Furthermore, the lubricating oil reservoir 23 is not limited to being provided only on the pinion shaft 10, and the lubricating oil reservoir 23 may be provided on both the pinion gear 9 and the pinion shaft 10. In this case, for example, as shown in FIG. 6 (f), the end surface 10a of the case 2 of the pinion shaft 10 on the rotation axis C side is on the same plane as the end surface 9b of the case 2 of the pinion gear 9 on the rotation axis C side. A lubricating oil reservoir 23 having a sloped peripheral wall 22 is provided at the end of the pinion gear 9 on the rotational axis C side of the case 2, and the peripheral wall 22 is sloped at the end of the pinion shaft 10 on the rotational axis C side of the case 2. The lubricating oil reservoir 23 can be provided. In this case, the volume of the lubricating oil reservoir 23 can be increased.

  Moreover, in the differential device 1 of this Embodiment mentioned above, although the pinion shaft 10 shall have a smooth outer peripheral surface, in the differential device which concerns on this invention, it is not limited to this, The pinion shaft 10 A lubricating oil groove 24 through which the lubricating oil 18 can be passed in the axial direction may be provided on the outer peripheral portion of the outer peripheral portion.

  In this case, for example, as shown in FIG. 7A, the outer periphery of the pinion shaft 10 may be provided with a lubricating oil groove 24 formed of a spline parallel to the axial direction, or as shown in FIG. A lubricating oil groove 24 formed of a spiral spline can be provided on the outer peripheral portion of the pinion shaft 10. By providing the lubricating oil groove 24 through which the lubricating oil 18 can flow in the axial direction on the outer peripheral portion of the pinion shaft 10, more lubricating oil 18 flows through the sliding portion 11 between the pinion gear 9 and the pinion shaft 10. Therefore, the reliability for preventing seizure between the pinion gear 9 and the pinion shaft 10 can be improved.

  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. 8, 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.

  Further, when two pinion gears 9 are provided, it is not limited to providing two pinion shafts 10, or two long pinion shafts 10 are shared by two pinion gears 9 as indicated by an imaginary line in FIG. 8. You may make it do.

  As described above, the differential according to the present invention is suitable for a case where the supply amount of lubricating oil blown from the drive pinion to the center side of the case to the sliding portion between the pinion gear and the pinion shaft is increased. Useful for all moving devices.

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 Pinion shaft 11 Sliding part 12 Supporting part 13 Opening part 18 Lubrication Oil 19 Support hole 22 Peripheral wall 23 Lubricating oil reservoir 24 Lubricating oil groove C Rotating shaft of case

Claims (7)

A case that can rotate around a rotation axis, a ring gear that is coaxially fixed to the case and at least a part of which is immersed in the lubricating oil and lifts the lubricating oil by rotation, and a hypoid pinion that meshes with the ring gear A drive pinion comprising: a first side gear comprising a bevel gear housed in the case and coaxially supported by the case and rotatably supported by the case; and a first side gear coupled to the first side gear and rotating integrally therewith. A first drive shaft, 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 the second drive shaft that rotates integrally, and is housed in the case and Two or more pinion gears comprising a bevel gear meshing with one side gear and the second side gear, and having a support hole penetrating the central portion along the rotation axis; and fitting into the support hole of the pinion gear; A pinion shaft that rotatably supports a pinion gear, a sliding portion that includes a gap between an inner peripheral surface of the support hole of the pinion gear and an outer peripheral surface of the pinion shaft, and the pinion shaft that is formed in the case And an opening that is formed between the support portions and communicates 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,
At least one of the pinion gear and the pinion shaft includes a space that is continuous with the rotation shaft side of the case of the gap of the sliding portion and opens toward the rotation shaft side of the case, and the lubrication A differential device comprising a lubricating oil reservoir capable of containing oil.   The said lubricating oil storage part is enclosed by the surrounding wall which continues from the peripheral edge by the side of the rotating shaft of the said case of the internal peripheral surface of the said support hole to the end surface by the side of the rotating shaft of the case of the said pinion gear. The differential device described in 1. The pinion shaft is fixed so as not to rotate with respect to the support portion, and the end surface of the pinion shaft on the rotating shaft side of the case is positioned on the same plane as the end surface of the pinion gear on the rotating shaft side of the case Or located on the outer peripheral side of the case,
The said lubricating oil storage part is enclosed by the surrounding wall which continues from the periphery of the rotating shaft side of the said case of the outer peripheral surface of the said pinion shaft to the end surface by the side of the rotating shaft of the said pinion shaft. Alternatively, the differential device according to claim 2.   4. The differential device according to claim 2, wherein the peripheral wall has a planar shape inclined with respect to a rotation axis of the pinion gear.   5. The differential device according to claim 1, further comprising a lubricating oil groove that allows the lubricating oil to flow in an axial direction on an outer peripheral portion of the pinion shaft. .   6. 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. 7. Differential.   6. 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. 7. Differential.

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