JPH08247260A - Lubricating structure for differential device - Google Patents

Abstract

PURPOSE: To reduce mixing loss of oil in a differential device and carry out lubrication surely. CONSTITUTION: In the lubricating structure of a differential device, an oil reservoir 23 for making lubricating oil scraped up by a ring gear 16 flow in and a first oil passage 22 are formed around a receiving part 6 in which a driving shaft 5 is housed. The first oil passage 22 is communicated between a front bearing 7 in the receiving part 6 and the oil seal 13 of an opening end side, and the oil reservoir 23 is communicated with a part between the front bearing 7 and the oil seal 13, and a part in which the ring gear 16 is housed in an axle housing 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating structure for a differential gear (differential gear) used as a final reducer for vehicles such as automobiles.

[0002]

2. Description of the Related Art As is well known, in this type of differential device, a drive pinion integral with a drive shaft and a large-diameter ring gear are housed in mesh with each other in a diff carrier, which is a hermetically sealed structure. The differential case has a pinion that meshes with the left and right side gears. In the banjo type differential device, the left and right axles connected to the side gears are inserted into the axle housing to transmit power to the left and right wheels.

Since it is difficult to adopt the forced lubrication system in this type of differential device, the splash lubrication system has been generally adopted. That is, the lubricating oil is filled to a predetermined level inside the differential carrier and the axle housing, the tooth surface of the ring gear is immersed in this lubricating oil, and the ring gear is not used for other tooth surfaces and bearings. By rotating and scraping up the lubricating oil and supplying the droplets, the lubrication of those parts is performed.

In such a lubrication system, the lubricating oil scraped up by the ring gear flows down along the inner surface of the differential carrier to supply the lubricating oil to the bearings and tooth surfaces. Since the lubricating oil is not forcibly guided to the bearings and the tooth surfaces that operate, the insufficient lubrication may occur depending on the behavior of the vehicle and the state of the lubricating oil. Therefore, for example, in the device disclosed in Japanese Utility Model Application Laid-Open No. 63-48054, a rib is formed on the ceiling portion of the portion housing the ring gear, and the lubricating oil scraped up by the ring gear is used by the rib to form a predetermined portion such as a bearing portion. It is configured so that it leads to the desired location. Therefore, with such a configuration, the lubricating oil scraped up by the ring gear can be effectively supplied to the lubricated portion, so that the amount of lubricating oil required can be reduced to some extent.

[0005]

In the device described in the above publication, although the lubricating oil scraped up by the ring gear is effectively supplied to the lubricated portion, the lubricating oil is guided to the lubricated portion by the rib. After being spilled, the ring gear immediately returns to the oil reservoir such as the bottom of the differential carrier, so that the ring gear must constantly scrape up a certain amount or more of lubricating oil. That is, since it is necessary to supply the lubricating oil to the oil reservoir to such a level that a part of the ring gear is submerged, there is a disadvantage that the lubricating oil is vigorously stirred by the ring gear and power loss due to stirring resistance is increased.

Especially recreational vehicles (RV vehicles)
When the nose angle of the differential device (the angle between the drive pinion axis and the horizontal surface on the ground) is large due to the high vehicle height as shown in Fig. 5, the amount of lubricating oil supplied to the bearings supporting the drive pinion is secured. Therefore, it is necessary to put a large amount of lubricating oil in the oil sump, so that the stirring loss of the lubricating oil becomes large. Further, as the number of rotations of the ring gear increases, the amount of lubricating oil scraped up also increases, so that the periphery of the drive pinion and the periphery of the bearing supporting it are filled with a large amount of lubricating oil. Therefore, as the vehicle speed increases, the stirring resistance of the lubricating oil by the drive pinion and the bearings that support it increases,
After all, there was an inconvenience that this contributed to power loss.

In order to eliminate such an inconvenience, it can be considered to reduce the amount of lubricating oil in the oil reservoir in the differential carrier and the axle housing as much as possible. By doing so, the stirring loss due to the ring gear etc. is reduced, but when the vehicle is traveling on a slope or traveling at high speed, lubricating oil will flow into the axle part of the axle housing. In such a case, the oil level in the oil sump will drop, and the amount of scraped up lubricating oil by the ring gear will be less than necessary.As a result, the bearing supporting the drive pinion, etc. May be insufficiently lubricated. So in the end,
It was necessary to prepare a certain amount or more of lubricating oil in the oil reservoir in the differential carrier and the axle housing, and it was difficult to reduce the power loss due to stirring resistance of the ring gear, drive pinion and the like.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lubrication structure of a differential gear capable of reducing agitation loss and maintaining good lubrication. is there.

[0009]

In order to achieve the above-mentioned object, the present invention is provided with a diff carrier projectingly provided on an axle housing, and at the inner peripheral side of a cylindrical receiving portion provided inside the diff carrier. A front bearing and a rear bearing that rotatably support the drive shaft are arranged, the opening end of the receiving portion is sealed with an oil seal, and a ring gear meshed with a drive gear provided at the end of the drive shaft. In a lubrication device of a differential device, which is housed inside the axle housing and configured to scrape and lubricate oil in the axle housing by the ring gear, an oil reservoir for flowing the lubricating oil scraped up by the ring gear A first oil passage is formed around the receiving portion, and the first oil passage is formed on the front shaft. And communicating between the oil seal,
In addition, the oil reservoir communicates with a portion between the front bearing and the oil seal and a portion of the axle housing that accommodates the ring gear.

Further, according to the present invention, it is possible to provide a second oil passage which connects a portion between the oil seal and the front bearing and a portion between the front bearing and the rear bearing.

[0011]

Therefore, according to the present invention, when the drive shaft is rotated, the ring gear meshing with the drive gear is rotated, and the oil contained in the differential carrier and the axle housing is scraped up. The oil scattered from the axle housing toward the differential carrier flows into the first oil passage and the oil reservoir provided in the differential carrier. Since the first oil passage communicates with the portion between the oil seal and the front bearing, the oil flowing into the first oil passage is supplied to the oil seal and the front bearing to lubricate and cool them.

Further, since the oil reservoir communicates with a portion between the oil seal and the front bearing, excess oil in the first oil passage flows into the oil reservoir and is temporarily stored therein. It is sequentially returned to the portion of the axle housing that accommodates the ring gear. On the other hand, when the supply of the lubricating oil via the first oil passage decreases, the oil in the oil reservoir flows between the front bearing and the oil seal to lubricate and cool the front bearing and the oil seal. .

Therefore, while the ring gear is rotating, a part of the oil is stored in the reservoir, so that the level of the oil in the portion of the axle housing where the ring gear is accommodated is lowered, and therefore the oil is agitated by the ring gear. Is mitigated, and even if the number of rotations of the ring gear increases, the oil in the receiving portion holding the drive shaft does not become excessive, and the stirring loss is suppressed also in this respect.

Further, if a second oil passage that connects the portion between the oil seal and the front bearing and the portion between the front bearing and the rear bearing is provided, the oil in the first oil passage or the oil in the reservoir can be provided. The second oil passage also supplies the rear bearing to lubricate and cool the rear bearing.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on the embodiments shown in the drawings. 1 to 7 show a first embodiment in which the present invention is applied to a banjo type differential device. The differential device 1 includes an axle housing 2 having a circular cross section as shown in FIG. A diff carrier 3 protruding forward in a conical shape is integrally provided. And the whole is constituted by the closed structure. Further, a drive shaft 5 is inserted into the differential carrier 3 in the vehicle front-rear direction, and the power output from the engine via the transmission is input via the drive shaft 5.

As shown in FIGS. 1 and 2, the differential carrier 3 is provided with a cylindrical receiving portion 6 inside an outer wall portion 3a thereof, and two tapered roller type bearings 7 are provided inside and outside the receiving portion 6. , 8 are fitted and fixed. It should be noted that the spacing between these bearings 7 and 8 is kept constant by a spacer 9. The drive shaft 5 integrated with the drive pinion 10 is rotatably supported by these two bearings 7 and 8.

An opening end 12 is provided in front of the front bearing 7 of the receiving portion 6 with a predetermined cylindrical portion 11 sandwiched therebetween, and the opening end 12 is liquid-tightly sealed by an oil seal 13. A flange 14 that is connected to a propeller shaft (not shown) is connected to the end of the drive shaft 5 that protrudes from the differential carrier 3 by a bolt.

The drive pinion 10 has a differential case 15
Meshes with the ring gear 16 integrated with the outer peripheral portion of the. The differential case 15 is rotatably supported by a bearing 17 provided inside the axle housing 2.
Inside thereof, two pairs of pinions 18 are rotatably held by a pinion shaft 19, and these pinions 18 mesh with the left and right side gears 20. An axle 21 inserted into the axle housing 2 is connected to each of the side gears 20, and the pinion 18 rotates to allow differential rotation of the left and right wheels.

A predetermined amount of oil O is contained in the bottoms of the axle housing 2 and the differential carrier 3, and a part of the ring gear 16 is immersed in the oil O. Since the ring gear 16 rotates in the direction of the arrow in FIG. 1, the oil O is scraped up by the ring gear 16 and scattered in the tangential direction.

Therefore, as shown in FIGS. 1 to 4, the first oil passage 22 extends from the upper opening 3b of the differential carrier 3 to the upper portion inside the differential carrier 3.
Are formed. Also, on the right side seen from the front,
An oil reservoir 23 having a large capacity is formed. Each of the first oil passage 22 and the oil reservoir 23 is configured to collect the oil scattered by the ring gear 16.

Explaining the first oil passage 22 and the oil reservoir 23, the outer wall portion 3a of the differential carrier 3 swells upward with respect to the receiving portion 6 and to the right side when viewed from the front (lower side in FIG. 2). And its outer wall 3a
A first oil passage 22 is formed between the inner surface of the portion that bulges upward and the upper outer surface of the receiving portion 6. Further, the oil reservoir 23 is a portion inside the outer wall portion 3a of the diff carrier 3 that bulges downward in FIG. 2, and does not reach the upper inner surface of the diff carrier 3 with the portion that houses the ring gear 16. It is partitioned by a weir 24 of height.

The weir 24 is formed in a state in which the rear side (ring gear 16 side) end portion of the receiving portion 6 and the axle housing 2 side end portion of the differential carrier 3 are connected to each other, and the lower end thereof is formed. Are continuously integrated into. This oil reservoir 24 and axle housing 2
As shown in FIG. 5, an outflow port 25 is formed at the lower end of the weir 24 in order to communicate with a portion of the inside of the weir that accommodates the ring gear 16.

In order to partition the first oil passage 22 and the oil reservoir 23, a rib 26 is provided along the longitudinal direction of the receiving portion 6 at a position close to the oil reservoir 23 side on the upper outer surface of the receiving portion 6. Has been formed. The rib 26 has a height which does not reach the inner surface of the outer wall portion 3a of the differential carrier 3, is continuous with the weir 24 at the rear end of the receiving portion 6, and the front end is shown in FIG. As described above, the differential carrier 3 is bent toward the oil reservoir 23 side before the end thereof. Therefore, the first oil passage 22 is formed on the upper side of the receiving portion 6 as a recessed portion extending from the rear side end portion to the front side end portion along the axial direction thereof and bent on the front side.

Then, in the bent portion on the front side,
Cylindrical portion 11 between the front bearing 7 and the oil seal 13
An inflow port 27 that opens to the bottom is formed. At the portion of the inflow port 27, the height of the rib 26 is gradually lowered toward the tip side, and the first oil passage 22 communicates with the oil reservoir 23 at this portion.

A second oil passage 28, which is isolated from the oil reservoir 23 and the first oil passage 22, is formed in the front side portion of the oil reservoir 23. The second oil passage 28 is provided in the cylindrical portion 11
Is for flowing oil from the front to the gap between the front bearing 7 and the rear bearing 8. That is, the partition wall 29 is integrally formed so as to connect the side outer surface of the receiving portion 6 and the side inner surface of the outer wall portion 3a of the differential carrier 3, and the partition wall 29 isolates the oil reservoir 23 and the first oil passage 22 from each other. The hollow part is formed. The hollow portion and the cylindrical portion 11 are provided on the side wall portion of the receiving portion 6.
There is formed an outflow port 30 for communicating with the above, and an inflow port 31 for communicating between the hollow portion and the gap between the front bearing 7 and the rear bearing 8. Therefore, the hollow portion forms the second oil passage 28 together with the outflow port 30 and the inflow port 31.

The oil is supplied to the bearings 7 and 8 through the inflow ports 28 and 31 and the outflow port 30, and the oil reservoir 23 and the axle housing 2 are used.
Since the oil is returned to the inside through the outlet 25, the inlets 28 and 31 and the outlets 25 and 30 are provided.
The opening area of is set to an area that ensures a sufficient and sufficient amount of oil supply to the bearings 7 and 8.

Next, the operation of the above-mentioned lubricating structure will be described. The power transmitted to the drive shaft 5 is transmitted from the drive pinion 10 to the ring gear 16 and the ring gear 16
And the differential case 15 integrated with this is rotated.
Further, power is transmitted from the differential case 15 to the left and right wheels via the pinion 18, the left and right side gears 20, and the axle 21. In that case, the left and right wheels are differentiated by the rotation of the pinion 18. Since a part of the ring gear 16 is submerged in the oil O of the axle housing 2, the tooth surface of the ring gear 16 is lubricated, and the oil O is scraped up as the ring gear 16 rotates in the direction of the arrow in the figure, and Since it is scattered throughout the inside of the axle housing 2, the other parts are lubricated by the scattered oil O.

Further, since the differential carrier 3 integrated with the axle housing 2 is provided with the first oil passage 22 and the oil reservoir 23 which communicate with the upper opening 3b of the differential carrier 3, the ring gear 16 is provided. A part of the oil O scattered in the tangential direction by the first oil passage 2 from the upper opening 3b.
2 and the oil reservoir 23. The oil O that has flowed into the first oil passage 22 flows therethrough to the tip side of the drive shaft 5, and further from the inlet 27 formed at the tip of the first oil passage 22 to the oil seal 13 and the front. It flows into the cylindrical portion 11 between the bearing 7. as a result,
The oil seal 13 and the front bearing 7 on the front end side of the differential carrier 3 are reliably lubricated and cooled by the oil O. In addition, the oil O flowing into the oil reservoir 23
Is temporarily stored here, and then flows back from the outflow port 25 to a portion of the axle housing 2 that houses the ring gear 16.

A part of the oil O flowing into the cylindrical portion 11 between the oil seal 13 and the front bearing 7 flows in the axial direction inside the front bearing 7 and reaches the rear bearing 8 side, but most of it is From the outflow port 30 through the second oil passage 28, the inflow port 31 flows between the two bearings 7 and 8.
Therefore, the oil O that has passed through the front bearing 7 and the oil O that has passed through the second oil passage 28 are supplied to the rear bearing 8, and the oil O lubricates and cools the rear bearing 8. The oil O that has passed through the rear bearing 8
Return inside the axle housing 2. In this way, the two bearings 7 and 8 in the differential carrier 3 are reliably lubricated and cooled by the oil O, and the drive shaft 5 is rotatably supported by the two bearings 7 and 8 satisfactorily.

The amount of oil O scattered depends on the rotational speed of the ring gear 16. When the rotational speed of the ring gear 16 increases together with the drive shaft 5, the amount of oil scattered increases accordingly. Therefore, the amount of oil flowing through the first and second oil passages 22 and 28 increases at high speed, and a large amount of oil O is supplied to the two bearings 7 and 8 to positively lubricate and cool them. The drive shaft 5 rotating at high speed is properly supported.

During high speed rotation, part of the large amount of oil O in the first oil passage 22 flows into the oil reservoir 23 immediately before the inflow port 27. Therefore, the oil O is not excessively supplied around the bearings 7 and 8 and the drive shaft 5, and as a result, the bearings 7 and 8 and the drive shaft 5 are
The stirring loss due to can be kept low.

Further, when the ring gear 16 is rotating at a rotational speed higher than a predetermined rotational speed, with respect to the amount of return of the oil O from the outflow port 25 to the portion of the axle housing 2 where the ring gear 16 is accommodated, Oil reservoir 23
Since the amount of oil O flowing into the oil reservoir and the amount of oil O diverted from the first oil passage 22 are increased, the oil O is gradually accumulated in the oil reservoir 23 and the amount thereof is increased. Therefore, the amount of oil O at the bottom of the axle housing 2 is
The oil level is reduced by the amount held in the oil reservoir 23, and the oil level is lowered. As a result, the degree of stirring of the oil O by the ring gear 16 is reduced, that is, the stirring loss of the oil O by the ring gear 16 is reduced.

During normal traveling, a certain amount of oil O is held in the oil reservoir 23 as described above, and therefore, a portion of the oil O in the axle housing 2 acts as a lateral acceleration when the vehicle turns. Even if the amount of oil scraped up by the ring gear 16 is drastically reduced due to the temporary movement in the axle direction by the oil, the oil O of the oil reservoir 23 is supplied from the inflow port 27 to the front bearing 7, and the second oil passage It is also supplied to the rear bearing 8 via 28. Even if the amount of the oil O scraped up by the ring gear 16 is reduced in this way, the oil O held in the oil reservoir 23 lubricates the inside of the differential carrier 3, so that inconveniences such as seizure of the bearings 7 and 8 can occur. Can be prevented. In this case, the oil reservoir 23
Since the oil O circulates from the outflow port 25 to the axle housing 2 at a constant flow rate and the oil O impinges on the ring gear 16 and the like, insufficient lubrication on the ring gear 16 side is also avoided.

By the way, since the oil O receives heat from the bearings 7, 8 and the like and is subjected to a shearing action by the ring gear 16 and the like, the temperature thereof gradually rises, but the oil O held in the oil reservoir 23 becomes Cooling is effectively performed by touching the outer wall portion 3a that is in contact with the outside air. As a result, the deterioration of the oil O is suppressed. In addition, the fins are added to the case outer wall of the differential carrier to increase the surface area,
It is also possible to improve the cooling effect of oil.

Next, another embodiment of the present invention will be described. As described above, the reduction of the stirring loss of the oil O by the ring gear 16 and the continuous lubrication of the bearings 7 and 8 can be obtained by always holding a predetermined amount of the oil O in the oil reservoir 23. On the other hand, the amount of oil O retained in the oil reservoir 23 depends on the amount of oil O scraped up by the ring gear 16 and the amount of oil O recirculated from the oil reservoir 23 into the axle housing 2 via the outlet 25. Decided. Further, if insufficient lubrication occurs at any place, the temperature rise of the oil O becomes remarkable.
Therefore, the oil reservoir 23 and the axle housing 2
It is preferable that a valve body made of a shape memory alloy that is opened at a predetermined temperature or higher is provided at the outflow port 25 between and. With such a configuration, the oil O is normally stored in the oil reservoir 23, and when a request for lubrication appears due to a rise in the temperature of the oil O, the oil O is stored in the axle housing 2 from the oil reservoir 23. Then, the ring gear 16 positively lubricates the ring gear 16 for splashing. That is, the oil O is stored in the oil reservoir 23 preferentially, so that the stirring loss can be reduced and the bearings 7 and 8 can be satisfactorily lubricated as in the above-described embodiment.

As another embodiment relating to the formation state and layout of the oil reservoir, as shown in FIG. 8, the oil reservoir may be formed separately and assembled to the bearing case. More specifically explaining the configuration shown in FIG. 8, an oil collecting portion 50 for collecting oil scattered from the ring gear is formed in the differential carrier 3 at a position similar to that of the first oil passage 22. The oil collecting portion 50 of the differential carrier 3 has a joint surface 51 that opens an inlet 51a communicating with the collecting portion 50 and an outlet 51b communicating with the portion of the axle housing 2 that accommodates the ring gear 16. It is provided on the side of. Further, a joint surface 52 having an inflow port 52a is formed on a side portion of the cylindrical portion between the oil seal and the front bearing.

On the other hand, the oil reservoir 53 is formed in a box shape separate from the differential carrier 3, and the oil reservoir 53 is formed.
A joint surface 54 having an inlet 54a and an outlet 54b
And a joint surface 55 having an inflow port 55a. Then, the oil reservoir 53 has the respective joint surfaces 5
4, 55 to the two joint surfaces 51 of the differential carrier 3,
52 is abutted via a seal member (not shown), and in this state, it is fixed to the differential carrier 3 by fastening means such as bolts.

Therefore, even in this embodiment, the oil scattered by the ring gear is not collected in the oil collecting portion 5.
It is collected at 0 and temporarily held in the oil reservoir 53.
Then, oil is introduced from the oil reservoir 53 into the inflow port 52a,
It is supplied to the front bearing and the like through 55a, and the outlet 5
Oil is returned to the axle housing 2 from 1b and 54b.

Regarding the layout of the oil reservoir, the oil reservoir 23 may be provided on the left side of the receiving portion 6 when viewed from the front of the differential carrier 3, as shown in FIG. Further, as shown in FIG. 10, the oil reservoir 23 can be arranged on both sides of the receiving portion 6.

Besides the banjo type, the differential device can be applied to an independent suspension type. This independent suspension type has a structure in which only the axles are projected from the left and right sides of the differential carrier, and the oil in the differential carrier does not move to the tire side when the vehicle turns. Therefore, the effect of seizure resistance at the time of turning the vehicle is small, but the other effects can be obtained.

[0041]

As described above, according to the lubricating structure of the differential device of the present invention, the oil scraped up by the ring gear is guided to the bearing through the first oil passage, while the oil provided inside the differential carrier is provided. Since the oil is temporarily stored in the reservoir, the oil level at the portion of the axle housing where the ring gear is housed can be lowered to reduce the oil stirring loss due to the ring gear.
Since a part of the oil flowing through the oil passage can be supplied to the oil reservoir, it is possible to reduce the excessive supply of oil to the bearings and the accompanying stirring loss, and when the amount of oil scraped up by the ring gear decreases, the oil reservoir The oil inside can lubricate the bearings. Therefore, according to the present invention, power loss due to excessive agitation of oil can be prevented, and good lubrication can be ensured regardless of the deterioration of the oil level in the axle housing. The effect can be obtained.

Further, in the lubrication structure of the differential device according to the present invention, if the portion between the oil seal and the front bearing and the portion between the front bearing and the rear bearing are connected by the second oil passage. Also, sufficient oil can be supplied to the rear bearing of the drive shaft to satisfactorily lubricate and cool it, and seizure of the rear bearing during vehicle turning can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a differential device for explaining an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a front view of a differential carrier.

FIG. 4 is a cross-sectional view showing an arrangement state of first and second oil passages and an oil reservoir.

FIG. 5 is a cutaway perspective view showing the shapes of the first and second oil passages and the oil reservoir.

FIG. 6 is a perspective view of a differential carrier.

FIG. 7 is an external perspective view of the entire banjo type differential device.

FIG. 8 is an exploded perspective view of the second embodiment of the present invention.

FIG. 9 is a front view of a differential carrier according to a third embodiment of the present invention.

FIG. 10 is a front view of a differential carrier according to a fourth embodiment of the present invention.

[Explanation of symbols]

 2 Axle housing 3 Differential carrier 5 Drive shaft 6 Receiving part 7 Front bearing 8 Rear bearing 10 Drive pinion 11 Cylindrical part 12 Opening end 13 Oil seal 16 Ring gear 22 First oil passage 23 Oil reservoir 28 Second oil passage

Claims (2)

[Claims] 1. A diff carrier is provided so as to protrude from an axle housing, and a front bearing and a rear bearing for rotatably supporting a drive shaft are arranged on an inner peripheral side of a cylindrical receiving portion provided inside the diff carrier. Further, an opening end of the receiving portion is sealed with an oil seal, and a ring gear meshed with a drive gear provided at an end portion of the drive shaft is housed inside the axle housing, and the ring gear allows the inside of the axle housing to be accommodated. In a lubrication structure of a differential gear configured to scrape up oil for lubrication, an oil reservoir and a first oil passage, into which the lubricating oil scraped up by the ring gear flows, are formed around the receiving portion. , The first oil passage communicates with the front bearing and an oil seal, and an oil reservoir Serial lubrication structure of a differential device, wherein the communicating with the portion containing the ring gear of the partial and the axle housing between the front bearing and oil seal. 2. A second oil passage is provided, which connects a portion between the oil seal and the front bearing and a portion between the front bearing and the rear bearing to each other. Lubrication structure of the differential gear described.