JP2020122531A - Lubrication structure of differential device - Google Patents

Abstract

To provide a lubrication structure of a differential device which can prevent the generation of the seizure and wear of a gear by equally supplying a lubricant to left and right directions in a differential case.SOLUTION: In a lubrication structure of a differential device 1, a lubricant stored at a bottom part in a transmission case 2 is scooped by the rotation of a final gear 7 attached to a differential case 3, and the scooped-up lubricant is supplied into the differential case 3 via a spiral groove 5 which is formed at internal peripheral faces of left and right inboard parts 3a of the differential case 3, thus lubricating each part. Lubricant passages 16L, 16R are formed at respective inner end parts of left and right axles 4L, 4R in an axial direction which are inserted and supported to the left and right inboard parts 3a of the differential case 3, and both the lubricant passages 16L, 16R are made to communicate with each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lubricating structure for a differential device for distributing rotational power from a drive source of a vehicle to a pair of left and right drive wheels.

A power transmission path of the vehicle is provided with a differential device (differential device) for distributing rotational power from a drive source such as an engine to a pair of left and right drive wheels. In this differential device, a pinion shaft is inserted and fixed in a differential case rotatably supported around a first axis by a transmission case in a direction of a second axis orthogonal to the first axis, and the differential case is provided in the differential case. In addition, a pair of pinion gears rotatably supported by the pinion shaft and a pair of side gears that mesh with the pinion gears and are rotatably supported about the first axis are housed. The left and right side gears are respectively connected to the outer peripheries of the inner end portions of the left and right axles that face the differential case.

In such a differential device, it is desirable to supply lubricating oil into the differential case in order to prevent power loss due to friction between each pair of pinion gears and side gears meshing with each other in the differential case and deterioration of durability due to wear. .. Therefore, various lubrication structures for differential devices have been proposed so far.

For example, in Patent Documents 1 to 3, the lubricating oil stored in the bottom portion of the transmission case is scraped up by the rotation of a final gear attached to the differential case, and the scraped lubricating oil is stored in the differential case. A lubricating structure has been proposed in which a helical groove is formed in either the inner peripheral surface of the inboard portion or the outer peripheral portion of the inner end portion of the axle to supply it into the differential case for lubrication of each portion.

Further, in Patent Document 4, a housing portion having a guide plate for guiding and collecting the lubricating oil scraped up by the final gear is provided in the differential case, and the lubricating oil collected by the housing portion is supplied to the lubricating oil passage. A lubrication structure has been proposed in which the oil is supplied to the inside of the differential case through the above to be used for lubrication of each part.

Further, in Patent Document 5, a first oil groove and a second oil groove are respectively formed on the left and right of the differential case, and lubricating oil supplied from a supply pipe is passed through the first oil groove and the second oil groove, respectively. A lubricating structure has been proposed in which it is supplied into the differential case to be used for lubrication of each part.

Japanese Utility Model Laid-Open No. 58-150650 JP-A-11-118028 JP, 2008-115987, A Japanese Utility Model Publication No. 62-194242 Utility model registration No. 2606235

However, in the lubrication structures proposed in Patent Documents 1 to 5, the supply amount of the lubricating oil scraped up by the final gear or the like is not uniform because the left and right in the differential case vary depending on the vehicle speed, the oil temperature, and the like. Therefore, the seizure or wear of the gear may occur due to the lack of the amount of lubricating oil on either the left or the right.

The present invention has been made in view of the above problems, and an object thereof is to provide a lubricating structure for a differential device capable of preventing the occurrence of seizure or wear of gears by supplying lubricating oil evenly to the left and right in the differential case. To provide.

In order to achieve the above-mentioned object, the present invention has a left and right inboard portions (3a) of a differential case (3) rotatably supported by a transmission case (2), and has respective ends of left and right axles (4L, 4R). The respective parts are rotatably inserted and supported, and the lubricating oil stored in the bottom part of the transmission case (2) is scraped up by the rotation of the final gear (7) attached to the differential case (3). The raised lubricating oil is provided with a spiral groove (which is formed on either the inner peripheral surface of the left and right inboard portions (3a) of the differential case (3) or the outer peripheral portion of the inner ends of the axles (4L, 4R). 5) The lubrication structure of the differential device (1), which is supplied to the differential case (3) through the differential case (3) and used for lubrication of each part, wherein the differential case (3) of the left and right axles (4L, 4R) is provided. ) Lubricating oil passages (16L, 16R) are axially formed at the respective inner ends inserted and supported by the left and right inboard portions (3a), and both lubricating oil passages (16L, 16R) are communicated with each other. A part of the lubricating oil scraped up by the final gear (7) is supplied into the differential case (3) through the lubricating oil passages (16L, 16R) communicating with each other. To do.

According to the lubricating structure of the differential device of the present invention, since the lubricating oil passages formed at the inner end portions of the left and right axles are communicated with each other, the lubricating oil scraped up by the final gear is left and right in the transmission case. When the supply amount is unbalanced, it is possible to balance the supply amount of the lubricant oil by supplying the lubricant oil on the side having the larger supply amount to the side having the smaller supply amount. Therefore, it is possible to evenly supply the lubricating oil to the left and right inside the differential case and prevent seizure and wear of the gear.

In the lubrication structure of the differential device, the left and right sides of the transmission case (2) are fitted to the inner circumferences of the left and right openings through which the left and right axles (4L, 4R) of the transmission case (2) pass. An annular oil reservoir (13L, 13R) partitioned by a bearing (6) rotatably supporting the attached oil seal (12) and the differential case (3) is formed, and the final gear (7) is formed. The lubricating oil scraped up by may be introduced into the left and right oil sumps (13L, 13R), respectively.

According to the above configuration, the lubricating oil scraped up by the final gear collides with the inner wall of the transmission case, then drops and is collected in the left and right oil sumps in the transmission case to be used for lubrication of each part.

Further, in the lubricating structure of the differential device, guide members (15) may be provided for guiding the lubricating oil scraped up by the final gear (7) to the left and right oil sumps (13L, 13R), respectively. good.

According to the above configuration, the lubricating oil scraped up by the final gear is efficiently introduced into the left and right oil sumps along the guide member.

Further, in the lubrication structure of the differential device, oil grooves (3b) communicating with the left and right oil sump portions (13L, 13R) are formed on the respective end surfaces of the left and right inboard portions (3a) of the differential case (3). And a first oil passage (4L, 4R) at each end of the left and right axles (4L, 4R) that connects the lubricating oil passages (16L, 16R) formed therein to the oil groove (3b). 19L, 19R) may be formed respectively.

According to the above configuration, the lubricating oil collected in the left and right oil sumps flows from the oil groove to the lubricating oil passage via the first oil passage and is used for lubrication of each portion.

In the lubrication structure of the differential device, the left and right axles (4L, 4R) are lubricated to the inner end portions of the left and right side gears (11) connected to the outer peripheries of the inner end portions. The radial second oil passages (20L, 20R) for supplying oil may be respectively formed.

According to the above configuration, the lubricating oil flowing from the lubricating oil passage into the second oil passage flows radially outward in the second oil passage due to the centrifugal force due to the rotation of the axle, and is used for lubricating the rear side of the side gear. To be done.

In the lubrication structure of the differential device, the lubricating oil passages (16L, 16R) formed at the inner ends of the left and right axles (4L, 4R) rotate together with the axles (4L, 4R). Then, screw shafts (22) for flowing the lubricating oil toward the inner end surfaces of the axles (4L, 4R) may be fitted respectively.

According to the above configuration, the lubricating oil is forcibly and vigorously flowed in the lubricating oil passage by the screw shaft that rotates together with the axle shaft, and is used for lubrication of each part.

According to the lubricating structure of the differential device of the present invention, it is possible to evenly supply the lubricating oil to the left and right in the differential case and prevent seizure and wear of the gear.

1 is a vertical cross-sectional view of a differential device including a lubrication structure according to a first embodiment of the present invention. FIG. 2 is an enlarged detailed view of an A part of FIG. 1. FIG. 3 is a vertical cross-sectional view of the main part of the differential device including the lubrication structure according to the first embodiment of the present invention. It is the BB sectional view taken on the line of FIG. FIG. 3 is a vertical cross-sectional view of a main part of a differential case of the differential device including the lubrication structure according to the first embodiment of the present invention. FIG. 3 is a perspective view of an axle of the differential device including the lubrication structure according to the first embodiment of the present invention. It is a longitudinal cross-sectional view of the differential device provided with the lubricating structure which concerns on Embodiment 2 of this invention. FIG. 8 is an enlarged detailed view of a C portion of FIG. 7. It is a longitudinal cross-sectional view of the differential device main part provided with the lubricating structure which concerns on Embodiment 2 of this invention. FIG. 6 is a perspective view of a screw shaft of a differential gear including a lubrication structure according to a second embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a vertical cross-sectional view of a differential device including a lubricating structure according to a first embodiment of the present invention, FIG. 2 is an enlarged detailed view of a portion A of FIG. 1, FIG. 3 is a vertical cross-sectional view of essential parts of the differential device, and FIG. 3 is a sectional view taken along the line BB of FIG. 3, FIG. 5 is a longitudinal sectional view of a main portion of a differential case of the differential device, and FIG. 6 is a perspective view of an axle of the differential device.

The differential device 1 shown in FIG. 1 distributes rotational power from a drive source (not shown) such as a vehicle engine to left and right drive wheels (not shown), and is housed in a transmission case 2 to A spherical shell-shaped differential case (hereinafter, abbreviated as “diff case”) 3 that is rotationally driven around a first axis C1 in the width direction (left-right direction in FIG. 1) is provided.

As shown in FIG. 1, the differential case 3 has a cylindrical inboard portion 3a for inserting and supporting the inner ends of the left and right axles 4L, 4R that face each other and have a small diameter. (1) in the left-right direction) is integrally projected. Here, as shown in FIG. 5 (only the left inboard portion 3a is shown in FIG. 5), a spiral groove 5 is formed on the inner peripheral surface of each of the left and right inboard portions 3a of the differential case 3. ..

The left and right inboard portions 3a of the differential case 3 are supported by the left and right bearings (taper roller bearings) 6 on the transmission case 2 so as to be rotatable about the first shaft center C1. Further, a ring-shaped flange portion 3A that stands upright in the vertical direction of FIG. 1 is integrally formed on the outer periphery of the differential case 3, and the rotational power output from a drive source such as an engine is provided in the flange portion 3A. A ring-shaped final gear (ring gear) 7 for inputting to the differential case 3 is attached by a plurality of bolts 8 (only one is shown in FIG. 1).

By the way, as shown in FIG. 1, the pinion shaft 9 is inserted and fixed in the center of the differential case 3 in the direction of the second axis C2 (the vertical direction in FIG. 1) orthogonal to the first axis C1. 3, a pair of left and right pinion gears (bevel gears) 10 rotatably supported by a pinion shaft 9 around a second axis C2, and the pinion gears 10 mesh with each other to rotate around a first axis C1. A pair of left and right side gears (bevel gears) 11 supported by the are housed. Here, the pair of pinion gears 10 are arranged vertically in FIG. 1 inside the differential case 3, and the pair of side gears 11 are arranged on both left and right sides of the pinion shaft 9 with the pinion shaft 9 interposed therebetween.

On the inner circumferences of the pair of side gears 11, a plurality of unillustrated spline teeth extending in the axial direction are respectively formed over the entire circumference, and these spline teeth are respectively formed on the left and right inboard portions 3a of the differential case 3. By fitting a plurality of axially long spline teeth 4a (in FIG. 6, only the left axle 4L is shown) formed on the outer circumferences of the inner ends of the left and right axles 4L and 4R passed through, The inner ends of the axles 4L and 4R are spline-fitted to the central portions of the left and right side gears 11, respectively. Therefore, the left and right side gears 11 and the left and right axles 4L, 4R integrally rotate about the first axis C1. Although not shown, left and right drive wheels are attached to the outer ends of the left and right axles 4L and 4R, respectively, and the left and right drive wheels rotate integrally with the left and right axles 4L and 4R.

By the way, as shown in FIG. 1, circular hole-shaped openings 2a are formed at the places where the left and right axles 4L, 4R of the transmission case 2 penetrate, and the inner periphery of these openings 2a is The oil seals 12 are fitted respectively. Here, although not shown, lubricating oil is stored in the bottom of the transmission case 2, and openings 2a through which the left and right axles 4L and 4R of the transmission case 2 penetrate are sealed by oil seals 12, respectively. Therefore, the sealing action of these oil seals 12 reliably prevents the lubricating oil in the transmission case 2 from leaking to the outside.

Here, the lubrication structure of the differential device 1 described above will be described.

As shown in FIG. 1, left and right oil seals 12, left and right bearings 6, left and right inboard portions 3 a of the differential case 3, which are the left and right parts of the differential device 1 in the transmission case 2 with the differential device 1 interposed therebetween. Annular oil reservoirs 13L and 13R are formed in the regions partitioned by the left and right axles 4L and 4R, respectively. Then, on the left and right sides of the transmission case 2, there is a plate shape for guiding the lubricating oil scraped up by the rotating final gear 7 to the left and right oil sumps 13L and 13R, respectively, as shown by the arrows in FIG. The guide member 15 is attached to the left and right bearings 6 and is provided.

Further, as shown in FIGS. 3 and 4, notch-shaped oil grooves 3b are respectively formed at two opposite positions on the end surfaces of the left and right inboard portions 3a of the differential case 3. 3b opens in oil reservoirs 13L and 13R formed on the left and right inside the transmission case 2, respectively.

By the way, as shown in FIGS. 1 and 2, circular hole-shaped lubricating oil passages 16L and 16R are formed along the axial direction at the axial centers of the inner ends of the left and right axles 4L and 4R, respectively. The lubricating oil passages 16L and 16R are in communication with each other. Specifically, as shown in FIGS. 2 and 3, the left and right lubricating oil passages 16L and 16R include a sleeve 17 that penetrates the pinion shaft 9 in a direction perpendicular to the axis (left and right directions in FIGS. 2 and 3), and Both ends of the sleeve 17 are connected to each other by left and right nipples 18 for connecting the left and right lubricating oil passages 16L and 16R.

Then, at the two axially spaced locations of the inner ends of the left and right axles 4L and 4R, the first oil passages 19L and 19R and the second oil passage 19L and 19R in the radial direction penetrating the respective lubricating oil passages 16L and 16R in a cross shape. The paths 20L and 20R are formed respectively. In other words, each of the left and right lubricating oil passages 16L and 16R has four first oil passages 19L and 19R and two second oil passages 20L and 20R formed radially outward.

The four first oil passages 19L, 19R and the second oil passages 20L, 20R are formed at equal angular pitches (90° pitch) in the circumferential direction at the inner ends of the left and right axles 4L, 4R, respectively. As shown in FIGS. 1 and 3 (only the first oil passage 19L on the left side is shown in FIG. 3), the four left and right first oil passages 19L and 19R are provided on the left and right inboard portions of the differential case 3. The oil groove 3b (see FIG. 4) formed on the end surface of 3a is selectively opened. Further, as shown in FIGS. 1 to 3 (only the second oil passage 20L on the left side is shown in FIG. 3), the four second oil passages 20L on the left and right sides are provided on the rear surface of the left and right side gears 11 and the differential case. 3, the oil passage 21 between the inner surface and the inner surface 3 is selectively opened.

Next, the operation of the differential device 1 having the above lubricating structure will be described.

When the rotational power output from the drive source such as the engine of the vehicle is input to the differential case 3 of the differential device 1 via the final gear 7, the differential case 3 rotates in the transmission case 2 around the first axis C1. The bottom of the transmission case 2 stores a sufficient amount of lubricating oil to immerse the final gear 7.

By the way, when the vehicle is traveling straight, the left and right drive wheels revolve from the road surface, so that the left and right pinion gears 10 revolve with the differential case 3 to transmit rotational power to the pair of left and right side gears 11. The left and right axles 4L and 4R that rotate together with the side gear 11 and the left and right drive wheels are rotationally driven. At this time, the pair of pinion gears 10 do not rotate (rotate).

On the other hand, during cornering when the vehicle turns, a difference occurs in the resistance received by the left and right drive wheels from the road surface (difference in moving distance between the left and right drive wheels), so that the pair of pinion gears 10 rotate and one side gear 11 rotates. Becomes faster than the rotation speed of the other side gear 11, so that the turning power is properly distributed to the left and right drive wheels while the vehicle corners smoothly.

As described above, when the differential gear 1 operates and the final gear 7 rotates together with the differential case 3, the final gear 7 scrapes up the lubricating oil stored in the bottom portion of the transmission case 2. Then, the scraped-up lubricating oil collides with the inner wall of the transmission case 2 and then drips as shown by the arrow in FIG. 1 to the left and right oil sumps 13L and 13R along the left and right guide members 15. It is introduced and collected efficiently.

The lubricating oil introduced into the left and right oil sump portions 13L, 13R in the transmission case 2 is partially partly discharged from the oil grooves 3b (see FIG. 4) formed on the end surfaces of the left and right inboard portions 3a of the differential case 3. It is introduced into the spiral groove 5 on the inner peripheral surface of the inboard portion 3a, and the other part is introduced into each of the four first oil passages 19L and 19R formed at the inner ends of the left and right axles 4L and 4R. And introduced respectively. Then, a part of the lubricating oil introduced into the spiral groove 5 formed on the inner peripheral surface of the inboard portion 3a of the differential case 3 is indicated by an arrow in FIGS. 1 and 3 (only one is shown in FIG. 3). Thus, as the left and right axles 4L and 4R rotate, they flow axially along the spiral groove 5, respectively, and pass through the oil passages 21 formed between the back surfaces of the left and right side gears 11 and the inner surface of the differential case 3 to reach the respective parts. Used for lubrication.

In addition, the other part of the lubricating oil introduced into the first oil passages 19L, 19R formed at the inner ends of the left and right axles 4L, 4R is supplied from the first oil passages 19L, 19R to the lubricating oil passage 16L, 16R and is introduced into the second oil passages 20L and 20R, respectively. Then, the lubricating oil introduced into the second oil passages 20L, 20R flows radially outward through the second oil passages 20L, 20R by the centrifugal force due to the rotation of the axles 4L, 4R, and the rear surfaces of the left and right side gears 11 are discharged. Through the oil passage 21 between the inner surface of the differential case 3 and the differential case 3, each part is lubricated.

In the above, in the present embodiment, since the lubricating oil passages 16L and 16R formed at the inner ends of the left and right axles 4L and 4R are communicated with each other, the transmission case 2 of the lubricating oil scraped up by the final gear 7 In the case where the left and right supply amounts are unbalanced, it is possible to supply the lubricating oil on the larger supply amount side to the smaller supply amount side to balance the lubricating oil supply amount on the left and right sides.

For example, as shown in FIG. 1, when the supply amount of lubricating oil is large on the right side and small on the left side, the surplus lubricating oil on the right side is supplied to the left side through the lubricating oil passages 16L and 16R communicating with each other. Therefore, the problem that the left pinion gear 10 and the side gear 11 are seized and worn due to the left and right balance of the supplied lubricating oil and the lack of lubricating oil on the left side of the differential case 3 is solved.

On the contrary, when the supply amount of the lubricating oil is large on the left side and small on the right side, the surplus lubricating oil on the left side is supplied to the right side through the lubricating oil passages 16L and 16R communicating with each other, so that the supplied lubrication is performed. This eliminates the problem that the right pinion gear 10 and the side gear 11 are seized and worn because the amount of oil is balanced on the left and right and the amount of lubricating oil is insufficient on the right side in the differential case 3.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIGS.

7 is a vertical cross-sectional view of a differential device including a lubricating structure according to a second embodiment of the present invention, FIG. 8 is an enlarged detailed view of a C portion of FIG. 7, FIG. 9 is a vertical cross-sectional view of a main part of the differential device, and FIG. FIG. 3 is a perspective view of a screw shaft of the differential device. In these figures, the same elements as those shown in FIGS. 1 to 6 are designated by the same reference numerals, and a repeated description thereof will be omitted below.

In the present embodiment, as shown in FIGS. 7 and 8, the lubricating oil passages 16L and 16R formed at the inner ends of the left and right axles 4L and 4R are rotated together with the axles 4L and 4R. The screw shaft 22 shown in FIG. 10 for flowing the lubricating oil toward the inner end surfaces of the axles 4L and 4R is fitted, and the other configuration is the same as that of the first embodiment. Here, as shown in detail in FIG. 8, each of the left and right screw shafts 22 has a nipple 23 connected to the inner end portion of each of the inner end portions of the lubricating oil passages 16L, 16R of the left and right axle shafts 4L, 4R. They are fixed by being respectively fitted to and are rotated integrally with the left and right rotating shafts 4L and 4R.

With the lubricating structure according to the present embodiment as well, similar to the lubricating structure according to the first embodiment, lubricating oil is evenly supplied to the left and right inside the differential case 3 to prevent seizure and wear of the pinion gear 10 and the side gear 11. As a result, the left and right screw shafts 22 rotate together with the left and right axle shafts 4L and 4R, so that the lubricating oil can be removed as shown by the arrows in FIG. 9 (only one is shown in FIG. 9). The lubricating oil passages 16L and 16R are forcibly and vigorously flowed to be used for lubrication of each portion, so that the lubricating effect of the lubricating oil is enhanced.

In the above embodiment, the spiral grooves 5 are formed on the inner peripheral surfaces of the left and right inboard portions 3a of the differential case 3, but the spiral grooves are formed on the outer peripheral surfaces of the inner end portions of the left and right axles 4L, 4R. You may do it.

In addition, the present invention is not limited to the application to the embodiment described above, and various modifications can be made within the scope of the technical idea described in the claims and the specification and the drawings.

1 differential device 2 transmission case 3 differential case 3a differential case inboard part 3b differential case oil groove 4L, 4R axle 5 spiral groove 6 bearing 7 final gear 9 pinion shaft 10 pinion gear 11 side gear 12 oil seal 13L, 13R oil sump 15 Guide member 16L, 16R Lubricating oil passage 17 Sleeve 18 Nipple 19L, 19R 1st oil passage 20L, 20R 2nd oil passage 21 Oil passage 22 Screw shaft 23 Nipple C1 1st shaft center C2 2nd shaft center

Claims (6)

The left and right inboard portions of the differential case rotatably supported by the transmission case are rotatably inserted through and supported by the respective end portions of the left and right axles, and the lubricating oil stored in the bottom portion of the transmission case is Rubbed up by the rotation of the final gear attached to the differential case, and the lubricated oil is formed on either the inner peripheral surface of the left and right inboard parts of the differential case or the outer periphery of the inner end of the axle. A lubricating structure of a differential device, which is configured to be supplied into the differential case through the formed spiral groove to be used for lubrication of each part,
A lubricating oil passage is formed axially in each inner end portion that is inserted and supported in the left and right inboard portions of the differential case of the left and right axles, and both lubricating oil passages are communicated with each other,
A lubricating structure for a differential device, characterized in that a part of the lubricating oil scraped up by the final gear is supplied into the differential case through the lubricating oil passages communicating with each other. An oil seal fitted to the inner periphery of the left and right openings of the transmission case, through which the left and right axles pass, and an annular ring defined by bearings that rotatably support the differential case. Form each oil sump,
The lubricating structure for the differential device according to claim 1, wherein the lubricating oil scraped up by the final gear is introduced into each of the left and right oil sumps. 3. The lubrication structure for the differential device according to claim 2, further comprising guide members for guiding the lubricating oil scraped up by the final gear to the left and right oil sumps, respectively. Oil grooves communicating with the left and right oil reservoirs are formed on the end surfaces of the left and right inboard portions of the differential case, respectively, and the lubricating oil passages formed on the end portions of the left and right axles are formed. 4. A lubrication structure for a differential device according to claim 2 or 3, wherein first oil passages that communicate with the oil groove are formed. A radial second oil passage is formed at each inner end of the left and right axles for supplying lubricating oil to the rear surface of each of the left and right side gears connected to the outer circumference of the inner end. The lubrication structure for the differential device according to claim 4, which is characterized in that. Screw shafts that rotate together with the respective axles and flow the lubricating oil toward the inner end surfaces of the axles are fitted in the lubricating oil passages formed at the inner end portions of the left and right axles, respectively. The lubricating structure for the differential device according to any one of claims 1 to 5.