JP2015212571A - Lubrication structure of final drive and lubrication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication structure of a final drive which makes compatible the reduction of a friction loss caused by agitation resistance and the reduction of defective lubrication, and a lubrication method.SOLUTION: In a lubrication structure of a final drive 1, a ring gear 7 and a drive pinion 3 engaged with the ring gear 7 are born and supported to a housing 2, a lubricant is stored in a lower oil sump 15 of the housing 2, and respective bearing support parts are lubricated while making the lubricant circulate by a scoop-up action accompanied by the engagement rotation of the ring gear 7 and the drive pinion 3. Then, in this embodiment, there is arranged an upper oil sump 20 which guides the scooped-up lubricant, stores it therein, and returns the stored lubricant to the lower oil sump 15 of the housing 2 at a prescribed flow rate.

Description

  The present invention relates to a lubricating structure and a lubricating method for a final drive (final reduction gear) in a driving system of an automobile.

  Conventionally, at the time of high-speed rotation, a final drive lubrication structure has been proposed in which not only the bearing portion on the drive pinion shaft side but also the bearing portion on the differential case side is sufficiently lubricated to prevent seizure or the like (Patent Document 1). reference). This is provided with an inflatable and shrinkable airbag on the upper inner wall surface of the carrier, which is in a contracted state when the ring gear rotates at a low speed and is inflated when the ring gear rotates at a high speed to increase its protruding amount. As a result, when the ring gear rotates at a low speed, the bearing on the drive pinion shaft side is lubricated by circulating the lubricating oil scraped up by the ring gear without being blocked by the airbag. In addition, during high-speed rotation, the air flow prevents the lubricating oil swung up by the ring gear from being blocked and directs a portion of the lubricating oil directly below so that even the bearing on the differential case side is sufficiently lubricated. I have to.

JP 2006-200730 A

  However, in the above-described conventional example, the amount of lubricating oil to be lifted increases as the rotational speed of the ring gear increases. For this reason, when high-speed rotation continues, the lubricating oil is lifted more than necessary by the ring gear, and there is a problem that agitation loss, that is, friction loss increases. This problem can be solved by reducing the amount of lubricating oil stored in the final drive to the minimum necessary to reduce the stirring resistance during high-speed rotation. There was a problem of poor lubrication at low speeds or immediately after starting.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a final drive lubrication structure and a lubrication method that achieve both reduction of friction loss due to stirring resistance and reduction of lubrication failure.

  In the present invention, a ring gear and a drive pinion meshing with the ring gear are respectively supported by bearings in the housing, and lubricating oil is stored in a lower oil sump of the housing, and lubrication is performed by a scraping action caused by meshing rotation of the ring gear and the drive pinion. It is a final drive lubrication structure that lubricates each bearing support portion while circulating oil. The present invention is characterized in that an upper oil sump is provided which introduces and stores the raked lubricating oil and returns the stored lubricating oil to the lower oil sump of the housing at a predetermined flow rate.

  Therefore, in the present invention, in the state where the ring gear is in the low speed rotation range, the amount of lubricating oil swept up by the ring gear and flowing into the upper oil sump is relatively small, while the return hole from the upper sump to the lower sump The amount of lubricating oil set by is returned. For this reason, the liquid level of the lubricating oil in the upper oil sump is maintained at a low level, and the liquid level of the lubricating oil in the lower oil sump can be in a high level state sufficient to immerse the meshing portion of the drive pinion and the ring gear. . Therefore, sufficient lubrication can be achieved without causing poor lubrication with respect to the engagement between the drive pinion and the ring gear due to low-speed driving of the vehicle, and the agitation resistance of the lubricating oil can be kept relatively low because the ring gear rotates at a low speed. .

  Also, as the ring gear rotates at a high speed due to an increase in the vehicle running speed, the amount of lubricating oil that is swept up by the ring gear and flows into the upper oil sump increases, while the return hole from the upper sump to the lower sump increases. The amount of lubricating oil set by is returned. For this reason, while the liquid level of the lubricating oil in the upper oil sump increases, the liquid level of the lubricating oil accumulated in the lower oil sump decreases. Accordingly, the lowering of the level of the lubricating oil in the lower oil sump reduces the ring gear portion immersed in the lubricating oil, thereby suppressing an increase in stirring resistance and an increase in the amount of lubricating oil to be swirled. Can be reduced.

It is sectional drawing of the lubricating structure of the final drive which shows 1st Embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing of the principal part of the lubricating structure of the final drive which shows 1st Example of 2nd Embodiment of this invention. FIG. 2 is a schematic configuration diagram (A) and an operation explanatory diagram (B) showing a lubricating structure of the final drive of the first embodiment. It is explanatory drawing which shows the lubrication structure of the final drive of 2nd Example. It is the schematic block diagram (A) and operation | movement explanatory drawing (B) which show the lubrication structure of the final drive of 3rd Example. It is the schematic block diagram (A) and operation | movement explanatory drawing (B) which show the lubrication structure of the final drive of 4th Example. FIG. 6 is a characteristic diagram showing a relationship between a liquid level of lubricating oil and friction loss.

  Hereinafter, the final drive lubrication structure and lubrication method of the present invention will be described based on each embodiment.

(First embodiment)
1 and 2 are a cross-sectional view and a main-part cross-sectional view showing a final drive lubrication structure to which the present invention is applied. As shown in FIGS. 1 and 2, the final drive 1 includes a drive pinion (hypoid pinion) 3 and a ring gear (hypoid ring gear) 7 that meshes with the drive pinion 3 in a housing 2.

  The drive pinion 3 is rotatably supported from a propeller shaft or the like via a flange provided at an end portion of the pinion shaft 4, with an integrated pinion shaft 4 rotatably supported on the housing 2 via a front bearing 5 and a rear bearing 6. Is done. The ring gear 7 is fixed to the outer periphery of a differential device (differential device) 8, and the differential device 8 is rotatably supported by the housing 2 via a pair of side bearings 9. The housing 2 includes a housing main body 2A and a rear cover 2B, and both are coupled to a vehicle body member (not shown) with bolts or the like.

  The differential device 8 rotates a pair of pinion mate gears 12 sharing a pinion mate shaft 11 and a pair of side gears 13 meshing with the pinion mate gears 12 in a differential case (hereinafter referred to as a differential case) 10. It is housed and arranged as possible. Each side gear 13 is connected to an axle shaft 14. The pinion mate gear 12 can revolve with the differential case 10 and can rotate around the axis of the pinion mate gear 12 itself. The ring gear 7 is fixed to the differential case 10 with bolts 15.

  Here, when attention is paid to the relationship between the pinion shaft 4 and the ring gear 7, the pinion shaft 4 is offset downward by a predetermined amount with respect to the axis (rotation center) of the ring gear 7, as is apparent from FIG. ing. Thus, the meshing portion between the drive pinion 3 and the ring gear 7 is located below the axis of the ring gear 7. Then, the lubricating oil reservoir (hereinafter referred to as “lower oil reservoir 15”) at the bottom of the housing 2 stores the lubricating oil to a level that allows the engagement portion of the drive pinion 3 and the ring gear 7 to be immersed. .

  As shown in FIG. 2, an opening 16 is provided in a part of the housing body 2 </ b> A in order to actively guide the lubricating oil flowing from the direction of the arrow B <b> 3 to the front bearing 5 and rear bearing 6 side of the pinion shaft 4. Is formed.

  In such a structure of the final drive 1, when the pinion shaft 4 is rotationally driven as is well known, both axle shafts 14 are rotationally driven with a differential in the differential device 8. At that time, the drive pinion 3 and the ring gear 7 immersed in the lubricating oil of the lower oil sump 15 scoop up the lubricating oil and circulate it, so that not only the meshing part between them but also the bearing 5 in the housing 2. Each part such as 6, 9 is lubricated.

  By the way, the amount of lubricating oil scooped up from the lower oil sump 15 by the drive pinion 3 and the ring gear 7 increases as the rotational speed of the gear increases. For this reason, when traveling at high speed, the lubricating oil is lifted more than necessary by the ring gear 7, and the agitation loss, that is, the friction loss increases, and the fuel consumption of the vehicle decreases.

  FIG. 8 is a characteristic diagram showing the change in friction loss with respect to the liquid level of the lubricating oil in the lower oil sump 15 when the vehicle is running at 100 km / h with the pinion shaft rotated at 3000 rpm. In the figure, the case where the lubricating oil temperature is 40 ° C. is indicated by the characteristic A, and the cases where the lubricating oil temperature is 60 ° C., 80 ° C. and 110 ° C. are indicated by the characteristics B, C and D. According to this characteristic diagram, the friction loss increases as the liquid level increases, and conversely decreases as the liquid level decreases. The friction loss increases as the temperature of the lubricating oil decreases, and conversely decreases as the lubricating oil temperature increases.

  Therefore, in the present embodiment, a lubrication structure of the final drive 1 suitable for reducing the stirring resistance during high-speed traveling is provided. For this reason, in this embodiment, the level of the lubricating oil stored in the lower oil sump 15 is set to a normal level in a region where the rotational speed of the ring gear 7 is relatively low, including when the vehicle is stopped. A liquid level adjustment device is provided for reducing the liquid level of the lubricating oil stored in the lower oil sump 15 as the speed increases.

  In this way, in the region where the rotational speed of the ring gear 7 is relatively low, including when the vehicle is stopped, the level of the lubricating oil stored in the lower oil sump 15 is set to the normal level so that it can be rotated at a low speed or immediately after starting. It is possible to eliminate poor lubrication. Further, as the rotational speed of the ring gear 7 increases, the level of the lubricating oil stored in the lower oil sump 15 is sequentially decreased, so that the stirring resistance during high-speed traveling can be reduced.

  The liquid level adjustment device temporarily introduces the lubricating oil flowing through the circulation path into the circulation path (downstream of the arrow B3 in the figure) of the lubricating oil scraped up by the ring gear 7 to the front bearing 5 and the rear bearing 6. An upper oil sump 20 is provided. The upper oil sump 20 is formed by a space provided with an opening 21 communicating with the internal space of the housing main body 2A so as to introduce the lubricating oil that is scooped up and scattered. The upper oil sump 20 has a predetermined volume capable of storing a liquid amount corresponding to the difference between the normal liquid level H of the lubricating oil stored in the lower oil sump 15 and the liquid level L during high speed rotation.

  The upper oil sump 20 can be integrally cast with the housing main body 2A by using a core when the housing main body 2A is cast. Further, the upper oil sump 20 may be provided separately from the housing main body 2A. When the container constituting the upper oil sump 20 is provided separately, a space for accommodating this container is formed in the housing main body 2A, and a separate container for forming the upper oil sump 20 is attached to the accommodation space. To.

  At the bottom of the upper oil sump 20, return holes 22 and 23 are formed to return the accumulated lubricating oil to the lower oil sump 15 at a preset flow rate. The flow rate of the lubricating oil flowing out from the return holes 22 and 23 is, for example, a predetermined amount of oil necessary for lubricating the meshing portion of the front bearing 5 and the rear bearing 6 or the drive pinion 3 and the ring gear 7 disposed downstream. Set by.

  The predetermined amount of oil necessary for lubrication of the meshing portion between the front bearing 5 and the rear bearing 6 or the drive pinion 3 and the ring gear 7 needs to be increased by increasing the rotational speed of the pinion shaft 4. For this reason, the predetermined amount of oil is set so as to correspond to the maximum value of the amount of oil necessary for the lubrication of the meshing portion between the front bearing 5 and the rear bearing 6 and the drive pinion 3 and the ring gear 7. The predetermined amount of oil is adjusted by the hole diameter of the return holes 22 and 23. In this embodiment, a lubricating oil return hole 22 to the front bearing 5 and the rear bearing 6 and a lubricating oil return hole 23 to the meshing portion of the drive pinion 3 and the ring gear 7 are provided separately. .

  The operation of the lubricating structure of the final drive 1 having the above configuration will be described below. When the vehicle is stopped, the drive pinion 3 and the ring gear 7 of the final drive 1 stop rotating, and the lubricating oil flowing into the upper oil sump 20 is also returned to the lower oil sump 15 through the return hole. The substantially entire amount of the lubricating oil filled in the housing 2 is accumulated in the lower oil sump 15. For this reason, the level of the lubricating oil in the lower oil sump 15 is the highest level in which the meshing portions of the drive pinion 3 and the ring gear 7 are sufficiently immersed. Therefore, even when the drive pinion 3 and the ring gear 7 are engaged with each other when the vehicle starts running, sufficient lubrication can be achieved without causing poor lubrication.

  In the state where the rotation speed of the ring gear 7 is in the low speed rotation region, as shown in FIG. 2, the ring gear 7 rotating while meshing with the drive pinion 3 has the lubricating oil stored in the lower oil sump 15 at its teeth. Is scraped up as indicated by arrows B1 and B2. A part of the lubricating oil swept up in this way collides with the upper inner surface of the housing 2 and is scattered in the housing 2, and meshes with the gears (pinion mate gear 12 and side gear 13) in the side bearing 9 and the differential case 10. Lubricate parts and sliding parts.

  Further, a part of the lubricating oil that has reached the upper space in the housing 2 is scattered toward the front of the vehicle by centrifugal force as indicated by an arrow B3 and flows into the upper oil sump 20 through the opening 21. The A part of the lubricating oil stored in the upper oil sump 20 is supplied to the meshing portion between the drive pinion 3 and the ring gear 7 through the return hole 23 as shown by an arrow B4, and then into the lower oil sump 15. Returned. Further, another part of the lubricating oil stored in the upper oil sump 20 is lubricated with the lower oil after lubricating the front bearing 55 and the rear bearing 6 of the pinion shaft 4 through the return hole 22 as indicated by an arrow B5. It is returned to the reservoir 15.

  The difference between the amount of lubricating oil flowing into the upper oil reservoir 20 and the amount of lubricating oil returned from the upper oil reservoir 20 via the return holes 22 and 23 remains in the upper oil reservoir 20. However, in the state where the rotation speed of the ring gear 7 is in the low speed rotation region, the amount of lubricating oil flowing into the upper oil sump 20 is not relatively large, so that the amount of lubricating oil remaining in the upper oil sump 20 is kept small due to the above difference. . For this reason, the level of the lubricating oil accumulated in the lower oil sump 15 is in an H level state sufficient to immerse the meshing portions of the drive pinion 3 and the ring gear 7. Accordingly, even when the drive pinion 3 and the ring gear 7 are engaged with each other when the vehicle is traveling at a low speed, sufficient lubrication can be achieved without causing poor lubrication. Further, since the rotational speed of the ring gear 7 is low, the amount of the lubricating oil that is swept up is relatively small, and the stirring resistance of the lubricating oil is also kept relatively low.

  As the traveling speed of the vehicle increases and the ring gear 7 rotates at a high speed, the amount of lubricating oil that is swept up by the ring gear 7 also increases. For this reason, the amount of lubricating oil flowing into the upper oil sump 20 also increases as the rotational speed of the ring gear 7 increases. On the other hand, the amount of lubricating oil returned from the upper oil sump 20 through the return holes 22 and 23 is equal to the level of the lubricating oil in the upper oil sump 20 with respect to the return amount predetermined by the return holes 22 and 23. Although it increases slightly according to the rise, it does not increase greatly. For this reason, the amount of lubricating oil remaining in the upper oil sump 20 is increased and the liquid level thereof is increased, while the liquid level of the lubricating oil remaining in the oil sump is lowered.

  When the liquid level of the lubricating oil in the upper oil sump 20 reaches the uppermost level of the upper oil sump 20, the liquid level of the lubricating oil accumulated in the lower oil sump 15 is in an L level state where it does not decrease any further. Become. As the liquid level of the lubricating oil in the lower sump 15 decreases, the ring gear 7 portion immersed in the lubricating oil decreases, and the increase in the amount of lubricating oil to be lifted is suppressed, and the increase in the stirring resistance of the lubricating oil is suppressed. can do. For this reason, it is possible to reduce the stirring loss, that is, the friction loss, while securing the amount of lubricating oil to the meshing portion of the drive pinion 3 and the ring gear 7 and the front bearing 5 and rear bearing 6 of the pinion shaft 4.

  When the vehicle is stopped from such a state, the rotation of the drive pinion 3 and the ring gear 7 of the final drive 1 is stopped, and the lubricating oil that has flowed into the upper oil sump 20 is also returned to the lower oil via the return holes 22 and 23. Returning to the reservoir 15, substantially the entire amount of the lubricating oil filled in the housing 2 is accumulated in the lower oil reservoir 15.

  In the above embodiment, the front bearing 5 and the rear bearing 6 or the engagement portion of the drive pinion 3 and the ring gear 7 are arranged in the return path of the lubricating oil from the upper oil sump 20 to the lower sump 15. explained. However, the lubricating oil may be directly returned from the upper oil reservoir 20 to the lower oil reservoir 15.

  In the present embodiment, the following effects can be achieved.

  (A) The bearing 2 supports the ring gear 7 and the drive pinion 3 meshing with the ring gear 7 in the housing 2, and the lubricating oil is stored in the lower oil sump 15 of the housing 2, and the meshing rotation of the ring gear 7 and the drive pinion 3 is performed. This is a lubricating structure of the final drive 1 that lubricates each bearing support portion while circulating the lubricating oil by the scooping action accompanying the above. The present embodiment is characterized in that an upper oil sump 20 is provided which introduces and stores the scraped lubricating oil and returns the stored lubricating oil to the lower oil sump 15 of the housing 2 at a predetermined flow rate. To do.

  For this reason, in the state where the ring gear 7 is in the low-speed rotation region, the amount of lubricating oil that is swept up by the ring gear 7 and flows into the upper oil reservoir 20 is relatively small, while the upper oil reservoir 20 to the lower oil reservoir 15 The amount of lubricating oil set by the return holes 22 and 23 is returned. For this reason, the level of the lubricating oil in the upper sump 20 is maintained at a low level, and the level of the lubricating oil in the lower sump 15 is high enough to immerse the meshing portion of the drive pinion 3 and the ring gear 7. Can be in level state. Therefore, sufficient lubrication can be achieved without causing poor lubrication with respect to the engagement between the drive pinion 3 and the ring gear 7 due to low-speed running of the vehicle, and since the ring gear 7 rotates at a low speed, the amount of lubricating oil to be swept up is relatively high The amount is small, and the stirring resistance of the lubricating oil can be kept relatively low.

  Further, as the traveling speed of the vehicle increases, the amount of lubricating oil that is swept up by the ring gear 7 and flows into the upper oil sump 20 increases as the ring gear 7 rotates at a high speed. 15, the amount of lubricating oil set by the return holes 22 and 23 is returned. For this reason, while the liquid level of the lubricating oil in the upper oil sump 20 increases, the liquid level of the lubricating oil accumulated in the lower oil sump decreases. Accordingly, the lowering of the level of the lubricating oil in the lower oil sump 15 reduces the ring gear 7 portion immersed in the lubricating oil, thereby suppressing an increase in stirring resistance and an increase in the amount of lubricating oil to be swept up, and stirring loss, that is, friction. Loss can be reduced.

  (A) At least a part of the bearing support portion, for example, the front bearing 5 and the rear bearing 6 are provided in a path for returning the lubricating oil from the upper oil reservoir 20 to the lower oil reservoir 15 of the housing 2. For this reason, the amount of lubricating oil to the bearing support portion, for example, the front bearing 5 and the rear bearing 6 of the pinion shaft 4 can be secured.

  (C) A meshing portion between the ring gear 7 and the drive pinion 3 is provided in a path for returning the lubricating oil from the upper oil reservoir 20 to the lower oil reservoir 15 of the housing 2. For this reason, the lubricating oil amount to the meshing part of the drive pinion 3 and the ring gear 7 can be ensured.

(Second Embodiment)
3 to 7 show a second embodiment of the lubrication structure and lubrication method of the final drive 1 to which the present invention is applied. FIGS. 3 and 4 show the first embodiment, and FIGS. It is a figure which shows 4 Examples. In the present embodiment, a configuration for increasing the supply of lubricating oil to the lubrication site in accordance with the speed state and motion state of the vehicle is added to the first embodiment. The same devices as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In FIG. 3, in the lubricating structure of the final drive 1 of the first embodiment, the amount of lubricating oil supplied to the front bearing 5 and the rear bearing 6 is increased in accordance with the traveling speed of the vehicle. . For this purpose, a return hole 24 communicating with the space between the front bearing 5 and the rear bearing 6 is provided at the bottom of the upper oil sump 20, and a valve body 25 (ball valve) for opening and closing the return hole 24 is disposed. The valve body 25 is opened according to the rotational speed of the pinion shaft 4. In addition, although the return hole 24 provided in the bottom part of the upper oil sump 20 of a present Example is comprised so that it may communicate directly with the space between the front bearing 5 and the rear bearing 6, it is different from 1st Embodiment. Similarly, it may be configured. In that case, the valve body 25 can be opened and closed by increasing the length of a member 25A described later provided on the valve body 25.

  Specifically, a ring-shaped magnet body 26 magnetized in a partial region of the circumference is fixed to the pinion shaft 4 and magnetized when facing the magnetized part of the magnet body 26 on the valve body 25 side. A member 25A made of an iron-based material that repels the part is attached and configured. Instead of the ring-shaped magnet body 26, as shown in FIG. 4A, a magnetized portion 26A for directly magnetizing a partial region in the circumferential direction of the outer periphery of the pinion shaft 4 itself may be provided. Good. Further, instead of providing the valve body 25 with the member 25A made of an iron-based material, the valve body 25 itself may be made of an iron-based material. Other configurations are the same as those in the first embodiment.

  Also in this example, as in the first embodiment, when the vehicle is traveling at a low speed, the lubricating oil stored in the lower oil sump 15 is set to a relatively low level of the lubricating oil stored in the upper oil sump 20. The oil level is relatively high. Further, as the rotational speed of the ring gear 7 increases, the liquid level of the lubricating oil stored in the upper oil reservoir 20 is increased, and the liquid level of the lubricating oil stored in the lower oil reservoir 15 is decreased. . For this reason, it is possible to eliminate poor lubrication during low-speed rotation or immediately after starting, while sequentially decreasing the liquid level of the lubricating oil stored in the lower oil sump 15 as the rotational speed of the ring gear 7 increases, This is common with the first embodiment in that the stirring resistance during high-speed running can be reduced.

  In this embodiment, when the pinion shaft 4 rotates, as shown in FIG. 4B, the ring-shaped magnetic body 26 rotates, and the magnetized region is the valve body 25 (iron-based member). When approaching / facing, the valve body 25 is repelled and lifted to release the return hole 24 and supply the lubricating oil in the upper oil sump 20 to the space between the front bearing 5 and the rear bearing 6. Works. Since the valve opening operation of the valve body 25 is increased in accordance with the rotational speed of the pinion shaft 4, that is, the vehicle speed, the valve body 25 is interposed between the front bearing 5 and the rear bearing 6 through the valve body 25 from the upper oil sump 20. The amount of lubricating oil supplied to the space is increased according to the rotational speed of the pinion shaft 4, that is, the vehicle speed. For this reason, the increased amount of lubricating oil required according to the increase in the rotational speed of the front bearing 5 and the rear bearing 6 can be ensured, and poor lubrication during high-speed rotation can be prevented.

  In addition, you may equip the bottom part of the upper oil sump 20 with the fixed return hole 22 of the predetermined cross section connected to the space between the front bearing 5 and the rear bearing 6 separately from the variable return hole 24 described above. In this case, the fixed amount return hole 21 is always open, and a predetermined return lubricating oil is always supplied to the front bearing 5 and the rear bearing 6 depending on the hole diameter. The amount of return lubricant from the fixed return hole 22 is set, for example, to the amount of lubricant required for each bearing during low-speed travel. Further, the variable return hole 24 can supply lubricating oil increased in accordance with the rotational speed of the pinion shaft 4, that is, the vehicle speed, to the front and rear bearings. For this reason, the amount of lubricating oil from the variable return hole 24 is set to an oil amount obtained by subtracting the predetermined amount of lubricating oil from the quantitative return hole 22 from the amount of lubricating oil required in each bearing due to the increase in vehicle speed. .

  In the second embodiment shown in FIG. 5, the upper oil sump 20 is provided with a variable return hole 24 at the bottom so as to communicate with the space between the front bearing 5 and the rear bearing 6, and the variable return hole 24 is opened and closed. The valve body 25 is opened and closed by a cam 27 provided on the pinion shaft 4. FIG. 5B is a side view of the cam 27. Other configurations are the same as those in the first embodiment.

  Also in this embodiment, as the pinion shaft 4 rotates, as shown in FIG. 5A, the cam 27 rotates, and the cam projection pushes up the valve body 25 to release the variable return hole 24. The lubricating oil in the upper oil sump 20 is supplied to the space between the front bearing 5 and the rear bearing 6. Since the valve opening operation of the valve body 25 is increased in accordance with the rotational speed of the pinion shaft 4, that is, the vehicle speed, the valve body 25 is interposed between the front bearing 5 and the rear bearing 6 through the valve body 25 from the upper oil sump 20. The amount of lubricating oil supplied to the space is increased according to the rotational speed of the pinion shaft 4, that is, the vehicle speed. For this reason, the increased amount of lubricating oil required according to the increase in the rotational speed of the front bearing 5 and the rear bearing 6 can be ensured, and poor lubrication during high-speed rotation can be prevented.

  In the third embodiment shown in FIG. 6, a variable return hole 24 is provided at the bottom of the upper oil sump 20 so as to communicate with the space between the front bearing 5 and the rear bearing 6, and the valve body for opening and closing the variable return hole 24. 25. A spring 28 is connected to the valve body 25 as shown in FIG. 6A, and the other end of the spring 28 is connected to the housing 2. The spring 28 urges the valve body 25 to be seated on the edge of the variable return hole 24. Other configurations are the same as those in the first embodiment.

  When the vehicle is stopped, the valve body 25 is seated on the edge of the variable return hole 24 by the spring 28 to close the variable return hole 24. When the vehicle starts traveling, the vehicle body vibrates through the wheels from the traveling road surface, and the final drive 1 also vibrates up and down, front and rear, left and right. With this vibration, as shown in FIG. 6B, the valve body 25 vibrates in the vertical and horizontal directions, vibrates away from the edge of the variable return hole 24, and moves the variable return hole 24 along with the vibration. release. As a result, the lubricating oil in the upper oil sump 20 is supplied to the space between the front bearing 5 and the rear bearing 6 through the variable return hole 24. The supply amount of the lubricating oil to the space between the front bearing 5 and the rear bearing 6 is increased or decreased according to the vibration amount of the valve body 25. The amount of vibration of the valve body 25 is small because the vertical / horizontal acceleration is low when the vehicle is traveling at a low speed, and is increased because the vertical / horizontal acceleration is increased as the vehicle is traveling at a high speed. Further, the vibration amount of the valve body 25 also increases and decreases due to the unevenness of the traveling road surface.

  The vibration (acceleration) in the vertical and horizontal directions applied to the vehicle body causes a change in torque applied to the drive pinion 3 and changes the load applied to the front bearing 5 and the rear bearing 6 that support the pinion shaft 4. For this reason, the amount of lubricating oil to the front bearing 5 and the rear bearing 6 can be increased or decreased according to these loads.

  In the fourth embodiment shown in FIG. 7, a variable return hole 24 is provided at the bottom of the upper oil sump 20 so as to communicate with the space between the front bearing 5 and the rear bearing 6, and the valve body for opening and closing the variable return hole 24. 25. As shown in FIG. 7 (A), the variable return hole 24 has a vehicle front-rear direction hole 24A whose rear end communicates with the upper oil sump 20 and has a large diameter and narrows into a tapered portion 29 on the front side of the vehicle. The hole 24 </ b> A is connected to the front end of the vehicle and is formed by a vertical hole 24 </ b> B that leads to a space between the front bearing 5 and the rear bearing 6. The valve body 25 is movable in the front-rear direction in the front-rear hole 24A and is urged forward by a spring 30 so as to be seated on the tapered portion 29 of the front-rear hole 24A. Other configurations are the same as those in the first embodiment.

  When the vehicle is stopped, the valve body 25 is seated on the tapered portion 29 of the front / rear direction hole 24 </ b> A in the variable return hole 24 by the spring 30 to close the variable return hole 24. When the vehicle starts traveling, as shown in FIG. 7B, the valve body 25 is moved against the spring 30 toward the vehicle rear side in accordance with the acceleration of the vehicle, and is separated from the tapered portion 29 to move back and forth. The hole 24A is brought into a communication state. As a result, the lubricating oil in the upper oil sump 20 is supplied to the space between the front bearing 5 and the rear bearing 6 through the variable return hole 24. The amount of movement of the valve body 25 is small because the acceleration is low when the vehicle is traveling steadily, and is large because the acceleration increases as the vehicle is accelerated. For this reason, the supply amount of the lubricating oil to the space between the front bearing 5 and the rear bearing 6 is increased or decreased according to the acceleration applied to the valve body.

  The acceleration applied to the vehicle increases the torque applied to the drive pinion 3 and increases the torque applied to the front bearing 5 and the rear bearing 6 that support the pinion shaft 4. For this reason, the amount of lubricating oil to the front bearing 5 and the rear bearing 6 can be increased or decreased according to these torques.

  In the above-described second to fourth embodiments, a description has been given of supplying lubricating oil to the space between the front bearing 5 and the rear bearing 6 only through the variable return hole 24. However, in these embodiments, similarly to the first embodiment, the fixed return hole 22 having a predetermined cross section communicating with the space between the front bearing 5 and the rear bearing 6 is formed at the bottom of the upper oil sump 20. 24 may be provided separately.

  In this case, the fixed amount return hole 22 is always open, and a predetermined return lubricating oil is always supplied to the front bearing 5 and the rear bearing 6 depending on the hole diameter. The amount of return lubricant from the fixed return hole 22 is set, for example, to the amount of lubricant required for each bearing during low-speed travel. Further, the variable return hole 24 can supply the front bearing 5 and the rear bearing 6 with the lubricating oil increased in accordance with the rotational speed (vehicle speed), vertical acceleration, and longitudinal acceleration of the pinion shaft 4. For this reason, the amount of lubricating oil from the variable return hole 24 is the amount of oil obtained by subtracting the predetermined amount of lubricating oil from the amount of lubricating oil required for each bearing due to the increase in vehicle speed, vertical acceleration, and longitudinal acceleration. Set.

  In the above embodiment, as a return path of the lubricating oil stored in the upper oil reservoir 20 to the lower oil reservoir 15, the front bearing 5 and the rear bearing 6 are targeted, and the vehicle speed, vertical acceleration, and longitudinal acceleration are increased. What was to be increased was explained. However, as a return path of the lubricating oil stored in the upper oil sump 20 to the lower oil sump 15, the increase in vehicle speed, vertical acceleration, and longitudinal acceleration is targeted for the meshing portion of the drive pinion 3 and the ring gear 7 It may be allowed.

  In the present embodiment, in addition to the effects (a) to (c) in the first embodiment, the following effects can be achieved.

  (D) As a meshing part or bearing support part between the drive pinion 3 and the ring gear 7 from the upper oil sump 20, for example, a predetermined return to the lower oil sump 15 via the front bearing 5 and the rear bearing 6 of the pinion shaft 4 The flow rate is increased as the rotational speed of the drive pinion 3 is increased. For this reason, the increased amount of lubricating oil required as the rotational speed increases can be secured, and poor lubrication during high-speed rotation can be prevented.

  (E) As a meshing part or bearing support part between the drive pinion 3 and the ring gear 7 from the upper oil sump 20, for example, a predetermined return to the lower oil sump 15 via the front bearing 5 and the rear bearing 6 of the pinion shaft 4 The flow rate is increased in accordance with an increase in vibration acting on the traveling vehicle. For this reason, the amount of lubricating oil can be increased or decreased in accordance with the load applied to the meshing part of the drive pinion 3 and the ring gear 7 or the bearing support part.

  (F) As a meshing portion or a bearing support portion between the upper oil sump 20 and the drive pinion 3 and the ring gear 7, for example, a predetermined return to the lower sump 15 via the front bearing 5 and the rear bearing 6 of the pinion shaft 4 The flow rate is increased as the acceleration toward the front of the vehicle increases. For this reason, the amount of lubricating oil can be increased or decreased according to the torque applied to the meshing part of the drive pinion 3 and the ring gear 7 or the bearing support part.

DESCRIPTION OF SYMBOLS 1 Final drive 2 Housing 3 Drive pinion 4 Pinion shaft 5 Front bearing 6 Rear bearing 7 Ring gear 8 Differential device 9 Side bearing 10 Differential case 15 Lower oil sump 16,21 Opening 20 Upper oil sump 22,23,24 Return hole 25 Valve body

Claims (7)

The ring gear and the drive pinion that meshes with the ring gear are supported by bearings in the housing, and the lubricating oil is stored in the lower oil sump of the housing, and the lubricating oil is circulated by the scraping action associated with the meshing rotation of the ring gear and the drive pinion. It is a final drive lubrication structure that lubricates each bearing support part,
A final drive lubrication structure, comprising an upper oil sump that introduces and stores the scraped lubricating oil, and returns the retained lubricating oil to the lower oil sump of the housing at a predetermined flow rate.   The final drive lubrication structure according to claim 1, wherein at least a part of the bearing support portion is provided in a path for returning the lubricating oil from the upper oil sump to the lower oil sump of the housing.   The final drive lubrication structure according to claim 1 or 2, wherein a meshing portion between the ring gear and the drive pinion is provided in a path for returning the lubricating oil from the upper oil sump to the lower sump of the housing. .   4. The final drive lubrication structure according to claim 2, wherein the predetermined flow rate is increased as the rotational speed of the drive pinion is increased. 5.   4. The final drive lubrication structure according to claim 2, wherein the predetermined flow rate is increased in accordance with an increase in vibrations acting on a running vehicle.   4. The final drive lubrication structure according to claim 2, wherein the predetermined flow rate is increased with an increase in acceleration forward of the vehicle. 5. The ring gear and the drive pinion that meshes with the ring gear are supported by bearings in the housing, and the lubricating oil is stored in the lower oil sump of the housing, and the lubricating oil is circulated by the scraping action associated with the meshing rotation of the ring gear and the drive pinion. It is a final drive lubrication method that lubricates each bearing support part while
Introducing and storing the scraped lubricating oil into the upper sump,
A final drive lubrication method, wherein the lubricating oil is returned from the upper oil sump to the lower sump of the housing at a predetermined flow rate.

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