JP7684197B2 - Differential lubrication system - Google Patents

Description

The present invention relates to a lubrication device for a differential device installed in a vehicle.

In a differential device installed in a vehicle, a lubrication device has been proposed that supplies lubricating oil to the differential mechanism housed in the differential case and the bearings that rotatably support the differential case. For example, Patent Document 1 discloses a structure for the lubrication device that includes lubrication piping for supplying lubricating oil to the differential mechanism and the bearings.

JP 2016-188705 A

However, in the configuration described in Patent Document 1 in which lubricating oil is supplied from a lubrication pipe, in order to reliably supply lubricating oil to the area requiring lubrication, it is necessary to extend the lubrication pipe to the vicinity of the area requiring lubrication. When extending the lubrication pipe to the vicinity of the area requiring lubrication, it is necessary to join multiple lubrication pipes and to adopt a shape in which the lubrication pipe branches into multiple paths, but this creates the problem of high manufacturing costs for the lubrication pipes.

The present invention was made against the background of the above circumstances, and its purpose is to provide a lubrication device for a differential device that can ensure the lubrication performance of the differential device without increasing manufacturing costs.

The gist of the present invention is (a) a lubrication device for a differential device that is applied to a differential device that includes a differential mechanism, a differential case that houses the differential mechanism, and a housing that rotatably supports the differential case via bearings, and that is provided with a lubrication pipe through which lubricating oil is supplied, and is configured to release the lubricating oil from a discharge port formed in the lubrication pipe, (b) the discharge port of the lubrication pipe is formed at a position that releases the lubricating oil toward the wall surface of the housing, (c) the wall surface of the housing that collides with the lubricating oil released from the discharge port is formed with a rib that guides the lubricating oil that has collided with the wall surface of the housing along the wall surface to a portion that requires lubrication, and (d) a member is disposed below the discharge port when the device is mounted on a vehicle, the member receiving the falling lubricating oil and having a trough portion formed with a tip that extends to the wall surface of the housing on which the rib is formed.

According to the present invention, when the lubricating oil is discharged from the discharge port of the lubricating pipe toward the housing, the lubricating oil that collides with the wall surface of the housing is guided along the rib to the part that needs lubrication. Even if the lubricating oil falls from the wall surface of the housing, the dropped lubricating oil is received by the gutter section, and the lubricating oil flows toward the wall surface of the housing via the gutter section. Furthermore, even if the lubricating oil discharged from the discharge port does not reach the wall surface of the housing due to the low temperature of the lubricating oil, the dropped lubricating oil is received by the gutter section, and the lubricating oil flows toward the wall surface of the housing via the gutter section. As a result, the lubricating oil can be supplied to the part that needs lubrication via the wall surface of the housing without extending the lubricating pipe to the vicinity of the part that needs lubrication, and the lubricating performance of the differential device can be ensured without increasing the manufacturing cost.

Also, preferably, in the present invention, the rib is formed to include a pair of side ribs erected in a direction perpendicular to the wall surface of the housing from both sides of the wall surface of the housing with which the lubricating oil discharged from the discharge port collides. In this way, the lubricating oil that collides with the wall surface of the housing is captured by the pair of side ribs, and the lubricating oil that collides with the wall surface of the housing can be efficiently guided to the area requiring lubrication.

1 is a cross-sectional view of a differential device to which the present invention is preferably applied. FIG. 4 is a perspective view of a rib formed on the housing. FIG. 13 is another perspective view of the rib formed on the housing. FIG. 4 is a diagram for explaining the shape of a baffle plate. FIG. 2 is an enlarged view of a portion in FIG. 1 where a baffle plate is disposed.

The following describes in detail the embodiments of the present invention with reference to the drawings. Note that in the following embodiments, the drawings have been simplified or modified as appropriate, and the dimensional ratios and shapes of each part are not necessarily drawn accurately.

Figure 1 is a cross-sectional view of a differential device 10 to which the present invention is preferably applied. Note that in Figure 1, the lower half of the differential device 10 with respect to the rotation axis CL is omitted. The differential device 10 is a well-known differential gear device that transmits power while allowing a difference in rotational speed between a pair of left and right wheels.

The differential device 10 is arranged around the rotation axis CL. The differential device 10 includes a differential case 12 that is supported rotatably around the rotation axis CL, a pinion shaft 14 that is housed in the differential case 12 and has both ends fixed to the differential case 12, a pinion 16 that is rotatably fitted to the outer periphery of the pinion shaft 14, a pair of left and right side gears 18L and 18R that mesh with the pinion 16, and a housing 40 that is a non-rotating member that rotatably supports the differential case 12 via a bearing (bearing 38R described later). The pinion shaft 14, the pinion 16, and the side gears 18L and 18R form a differential mechanism 20.

The differential case 12 has a space 22 formed therein to accommodate the differential mechanism 20. A pair of boss holes 24L, 24R are formed on both sides of the rotation axis CL of the differential case 12, into which a pair of left and right drive shafts 28L, 28R are fitted. The space 22 in which the differential mechanism 20 is accommodated and the pair of boss holes 24L, 24R are spatially continuous with each other. A pair of through holes 26 through which the pinion shaft 14 is inserted are formed on both ends of the differential case 12 in a direction perpendicular to the rotation axis CL. Note that only one of the through holes 26 is shown in FIG. 1. A differential ring gear 32 is fixed to the outer periphery of the differential case 12 by bolts or press fitting (not shown).

The pinion shaft 14 is composed of a cylindrical member extending in the longitudinal direction. The pinion shaft 14 is fixed to the differential case 12 so that it cannot fall off, with both ends in the longitudinal direction inserted into a pair of through holes 26. The pinion shaft 14 is rotated together with the differential case 12 about the rotation axis CL.

The pinion 16 is formed in an annular shape, and the pinion shaft 14 passes through it. The pinion 16 is supported so as to be rotatable around the pinion shaft 14. Although omitted in FIG. 1, the pinion 16 is provided on each end of the pinion shaft 14.

The pair of left and right side gears 18L, 18R are each composed of a hollow annular member. The drive shaft 28L is splined to the inner periphery of the side gear 18L, and the drive shaft 28R is splined to the inner periphery of the side gear 18R. The pair of side gears 18L, 18R are arranged to be rotatable about the rotation axis CL. The pair of side gears 18L, 18R are also arranged to correspond to each other across the pinion shaft 14. The pinion 16 and the side gears 18L, 18R form bevel gears whose rotation axes intersect perpendicularly to each other.

One end of the differential case 12 in the direction of the rotation axis CL is rotatably supported by a housing 40, which is a non-rotating member, via a bearing 38R. Although not shown, the other end of the differential case 12 in the direction of the rotation axis CL is also rotatably supported by a non-rotating member via a bearing 38L. The non-rotating member that holds the bearing 38L may be the housing 40, or it may be a member different from the housing 40.

Next, the lubrication device 42 that supplies lubricating oil to the parts that require lubrication (hereinafter, lubrication-requiring parts), such as the differential mechanism 20 and the bearings 38R that constitute the differential device 10, will be described. The lubrication device 42 is composed of a tube 48 shown in FIG. 1, a rib 62 formed on the housing 40, and a gutter portion 72 formed on the baffle plate 60, which will be described later. The structures and functions of the tube 48, rib 62, and gutter portion 72 will be described later.

When the housing 40 is viewed radially around the rotation axis CL, at least a portion of the housing 40 overlaps with the differential case 12. The housing 40 is formed with a lubricating oil supply passage 46 through which lubricating oil is supplied from a hydraulic control circuit (not shown). The housing 40 is further formed with a lubricating oil receiving passage 50 connected to a communication passage (not shown). The lubricating oil supply passage 46 and the lubricating oil receiving passage 50 are connected to each other via a tube 48. That is, one end of the tube 48 is connected to the lubricating oil supply passage 46, and the other end of the tube 48 is connected to the lubricating oil receiving passage 50. The lubricating oil receiving passage 50 is connected to a communication passage (not shown), and is configured so that lubricating oil is supplied to parts other than the differential device 10 through the communication passage.

The tube 48 is made of, for example, a steel pipe for piping. The tube 48 is supplied with lubricating oil from the lubricating oil supply passage 46, so that the lubricating oil flows through the tube 48. The tube 48 extends in the direction of the rotation axis CL from one end connected to the lubricating oil supply passage 46, is bent in front of the differential ring gear 32, and extends vertically downward toward the differential case 12. Next, the tube 48 is bent in front of the baffle plate 60 and extends in the direction of the rotation axis CL toward the housing 40. Furthermore, the tube 48 is bent in front of the rib 62 formed on the housing 40 and extends upward, and is bent toward the lubricating oil receiving passage 50 in the vicinity of the lubricating oil receiving passage 50, so that the other end of the tube 48 is connected to the lubricating oil receiving passage 50. By bending the tube 48 as described above, as shown in FIG. 1, the tube 48 is piped so as to make a circle around the vertically upper part of the differential case 12, drawing an approximately rectangular shape. The tube 48 is fixed with a clamp 52 or the like to prevent it from shifting position while traveling. The tube 48 corresponds to the lubrication pipe of the present invention.

The tube 48 has a first outlet 54, a second outlet 56, and a third outlet 58 formed along its path, and the lubricating oil discharged from the first outlet 54 to the third outlet 58 is supplied to parts requiring lubrication. The first outlet 54 is formed in a position facing the differential case 12, vertically above the differential case 12 when mounted on the vehicle. In detail, when the differential device 10 is viewed from vertically above in the vehicle mounted state shown in FIG. 1, the first outlet 54 is formed at a position overlapping with or near the rotation axis CL, and at a position or near the position where the pinion shaft 14 is located in the direction of the rotation axis CL.

The second discharge port 56 is formed at a position facing the wall surface 40a of the housing 40. In other words, the second discharge port 56 is formed at a position that discharges the lubricating oil toward the wall surface 40a of the housing 40. The third discharge port 58 is formed near the lubricating oil receiving passage 50. The second discharge port 56 corresponds to the discharge port of the present invention.

In FIG. 1, the arrows formed on the tube 48 indicate one mode of the flow of the lubricating oil supplied from the lubricating oil supply passage 46. As shown in FIG. 1, the lubricating oil flows inside the tube 48 from the lubricating oil supply passage 46 toward the lubricating oil receiving passage 50. The lubricating oil flowing inside the tube 48 is released from the first release port 54 to the third release port 58, respectively.

The lubricating oil discharged from the first discharge port 54 is discharged vertically downward toward the differential case 12. A baffle plate 60 (described later) is provided between the first discharge port 54 and the differential case 12, and the lubricating oil discharged from the first discharge port 54 is supplied to the differential case 12 through a through hole 76 formed in the baffle plate 60. The lubricating oil that reaches the differential case 12 flows into the space 22 of the differential case 12 through, for example, a gap between the through hole 26 formed in the differential case 12 and the pinion shaft 14, and lubricates each gear of the differential mechanism 20.

The lubricating oil discharged from the second discharge port 56 is discharged toward the wall surface 40a of the housing 40. The lubricating oil adhering to the wall surface 40a of the housing 40 moves downward along the wall surface 40a of the housing 40 as shown by the arrow, lubricating the parts requiring lubrication, including the bearing 38R. Although some of the lubricating parts adhering to the wall surface 40a of the housing 40 fall from the wall surface 40a, the fallen lubricating oil is received by the gutter portion 72 of the baffle plate 60, which will be described later, and is supplied to the parts requiring lubrication via the gutter portion 72. By discharging the lubricating oil from the multiple discharge ports (first discharge port 54 to third discharge port 58) formed in the tube 48, it becomes possible to supply the lubricating oil to multiple parts requiring lubrication with a single tube 48.

Next, the rib 62 formed on the housing 40 will be described. As described above, since the tube 48 is composed of a single pipe, the tube 48 cannot be extended to the vicinity of each part of the differential device 10 that requires lubrication. In contrast, the bearing 38R is configured so that the lubricating oil discharged from the second discharge port 56 toward the wall surface 40a of the housing 40 is supplied along the rib 62. Here, it is desired that the lubricating oil discharged toward the wall surface 40a of the housing 40 efficiently reaches the bearing 38R. Therefore, the rib 62 formed on the wall surface 40a of the housing 40 on which the lubricating oil discharged from the second discharge port 56 collides is formed so that the lubricating oil that collides with the wall surface 40a is efficiently guided to the bearing 38R.

Figure 2 is a perspective view of a rib 62 formed on the housing 40. Note that a portion of the tube 48 through which the lubricating oil flows is depicted at the top of the page in Figure 2, and the arrows depicted around the tube 48 indicate the flow of the lubricating oil released from the second outlet 56 of the tube 48. As shown by the arrows in Figure 2, the position at which the second outlet 56 is formed varies from product to product, which causes variation in the direction in which the lubricating oil is released from the second outlet 56.

The rib 62 formed on the housing 40 is formed so that even if the direction of the lubricating oil discharged from the second discharge port 56 varies, the lubricating oil is retained within the rib 62, and the lubricating oil is guided along the rib 62 to the bearing 38R, etc. In FIG. 2, the rib 62 is formed from a pair of side ribs 62a, 62b formed to sandwich the tube 48, and a Y-shaped rib 62c formed in a Y shape.

The pair of side ribs 62a, 62b are each erected from the wall surface 40a of the housing 40 toward the second discharge port 56. In addition, the pair of side ribs 62a, 62b each extend longitudinally toward the side where the bearing 38R is located.

The pair of side ribs 62a, 62b are formed on both sides of the wall surface 40a of the housing 40 against which the lubricating oil discharged from the second discharge port 56 collides. The pair of side ribs 62a, 62b are arranged at a predetermined interval when the housing 40 is viewed in the direction of the rotation axis CL. The interval formed between the pair of side ribs 62a, 62b is set to a range in which the lubricating oil discharged from the second discharge port 56 can be retained within the groove 66 formed by the pair of side ribs 62a, 62b, that is, a range in which the lubricating oil discharged from the second discharge port 56 toward the wall surface 40a can be captured regardless of the product variation of the second discharge port 56. In addition, the wall surface 40a of the housing 40 facing the second discharge port 56, sandwiched between the pair of side ribs 62a, 62b, is formed into a smooth curved shape so that the rebound of the lubricating oil discharged from the second discharge port 56 is reduced.

The Y-shaped rib 62c is formed so as to be sandwiched between a pair of side ribs 62a, 62b. The Y-shaped rib 62c is formed from a pair of bifurcated branch ribs 64a, 64b, and a center rib 64c connected to the branch ribs 64a, 64b. The pair of branch ribs 64a, 64b are connected to the pair of side ribs 62a, 62b, respectively. The center rib 64c is formed in a protruding shape into which the lubricating oil guided by the pair of branch ribs 64a, 64b flows.

Figure 3 is a perspective view of the rib 62 formed on the housing 40 in Figure 2, seen from a different direction than that of Figure 2. As shown in Figure 3, a center rib 64c is formed continuous with the portion where the branch rib 64a and the branch rib 64b of the Y-shaped rib 62c are connected to each other. When mounted on the vehicle, the center rib 64c protrudes vertically downward. As shown in Figure 1, the center rib 64c has a predetermined dimension in the direction of the rotation axis CL along the wall surface 40a of the housing 40.

By forming the rib 62 as described above, the lubricating oil discharged from the second discharge port 56 of the tube 48 is retained in the groove 66 formed by the pair of side ribs 62a, 62b, and the lubricating oil is prevented from escaping from the groove 66. In addition, the lubricating oil retained in the groove 66 is guided by the branch ribs 64a, 64b of the Y-shaped rib 62c, as shown by the arrows in Figures 2 and 3, into the center rib 64c, and moves downward to the housing 40 along the protruding portion of the center rib 64c. In this way, the lubricating oil discharged from the second discharge port 56 toward the wall surface 40a of the housing 40 is appropriately captured by the rib 62. Furthermore, the lubricating oil moves downward along the rib 62, so that the lubricating oil is efficiently supplied to the bearing 38R arranged below the rib 62.

Next, the baffle plate 60 provided between the differential case 12 and the housing 40 and the gutter portion 72 formed in the baffle plate 60 will be described. In the vehicle-mounted state shown in FIG. 1, the baffle plate 60 made of resin or the like is provided between the differential case 12 and the housing 40, vertically below the tubes 48. FIG. 4 is a diagram for explaining the shape of the baffle plate 60. FIG. 4(a) corresponds to a perspective view of the baffle plate 60, and FIG. 4(b) corresponds to a view of the baffle plate 60 viewed vertically from above in the vehicle-mounted state shown in FIG. 1. The baffle plate 60 corresponds to the member in which the gutter portion of the present invention is formed.

The baffle plate 60 includes a main body 70 formed in a cylindrical shape, a gutter portion 72 formed on the outer peripheral surface of the main body 70, and a flange portion 74 formed in the circumferential direction of the main body 70 to avoid the portion where the gutter portion 72 is formed.

The main body 70 is formed in a cylindrical shape so as to cover the differential case 12 when mounted on the vehicle as shown in FIG. 1. When mounted on the vehicle as shown in FIG. 1, the main body 70 is inclined in a direction such that the outer diameter becomes smaller as it approaches the housing 40 with respect to the rotation axis CL.

The gutter section 72 is disposed below the second discharge port 56 and vertically below the center rib 64c extending along the wall surface 40a toward the rotation axis CL in the vehicle-mounted state shown in FIG. 1 so as to receive the lubricating oil that has fallen from the second discharge port 56 and the rib 62 (mainly the center rib 64c) of the housing 40. The gutter section 72 is formed from a pair of side ribs 72a, 72b erected radially outward from the outer circumferential surface of the main body section 70. In addition, the gutter section 72 is extended in the direction of the rotation axis CL beyond the main body section 70 so that the tip is located near the wall surface 40a of the housing 40 on which the rib 62 is formed on the rotation axis CL in the vehicle-mounted state shown in FIG. 1. In addition, a through hole 76 is formed in the outer circumferential surface of the main body section 70 sandwiched between the pair of side ribs 72a, 72b, which is located vertically below the first discharge port 54 in the vehicle-mounted state shown in FIG. 1.

Next, the flow of lubricating oil by the lubricating device 42 that lubricates the differential device 10 will be described. FIG. 5 is an enlarged view of the area in FIG. 1 where the baffle plate 60 and the rib 62 of the housing 40 are formed. The lubricating device 42 includes the tube 48, the rib 62 of the housing 40, and the gutter portion 72 of the baffle plate 60, as shown in FIG. 5. The arrows in FIG. 5 indicate the flow of lubricating oil discharged from the first discharge port 54, the second discharge port 56, etc. of the tube 48.

In FIG. 5, the lubricating oil discharged from the first discharge port 54 of the tube 48 reaches the differential case 12 mainly through the through holes 76 (see FIGS. 1 and 4) formed in the baffle plate 60, as shown by the solid arrows. The lubricating oil that reaches the differential case 12 is supplied to the differential mechanism 20 housed in the differential case 12 through the gap between the through holes 26 of the differential case 12 and the pinion shaft 14, etc.

The lubricating oil discharged from the second discharge port 56 of the tube 48 collides with the wall surface 40a of the housing 40 as indicated by the solid arrow in FIG. 5. At this time, even if the direction of the lubricating oil discharged from the second discharge port 56 varies, the lubricating oil is captured by a pair of side ribs 62a, 62b that constitute the rib 62. The lubricating oil that collides with the wall surface 40a passes through the branch ribs 64a, 64b that constitute the Y-shaped rib 62c and is collected in the center rib 64c that is formed in a protruding shape. Furthermore, the lubricating oil moves along the center rib 64c to the lower side of the housing 40. The lubricating oil that has moved to the lower side of the housing 40 is supplied to parts that require lubrication, such as the bearing 38R (not shown in FIG. 5).

In addition, some of the lubricating oil that reaches the rib 62 falls from the rib 62 (mainly the center rib 64c) as shown by the dashed arrow. Even in this case, the lubricating oil that falls from the rib 62 is received by the gutter portion 72 formed in the baffle plate 60. As a result, the lubricating oil flows through the gutter portion 72 toward the wall surface 40a side of the housing 40, and the lubricating oil is supplied to the bearing 38R and the like along the wall surface 40a. In addition, when the lubricating oil is at a low temperature (i.e., when the lubricating oil is highly viscous) or when the vehicle is tilted, such as when traveling on an uphill lane, the lubricating oil discharged from the second discharge port 56 may not reach the wall surface 40a, or the lubricating oil may fall from above the housing 40, as shown by the dashed arrow in FIG. 5. Even in this case, the lubricating oil that falls is received in the gutter portion 72 of the baffle plate 60, and the lubricating oil flows through the gutter portion 72 toward the wall surface 40a of the housing 40, and the lubricating oil runs down the wall surface 40a and is supplied to the bearing 38R, etc.

As described above, according to this embodiment, when the lubricating oil is discharged from the second discharge port 56 of the tube 48 toward the housing 40, the lubricating oil that hits the wall surface 40a of the housing 40 is guided along the rib 62 to the parts that require lubrication, such as the bearing 38R. Even if the lubricating oil falls from the wall surface 40a of the housing 40, the dropped lubricating oil is received by the gutter portion 72, and the lubricating oil flows toward the wall surface 40a of the housing 40 via the gutter portion 72. Furthermore, even if the lubricating oil discharged from the second discharge port 56 does not reach the wall surface 40a of the housing 40 due to the low temperature of the lubricating oil, for example, the dropped lubricating oil is received by the gutter portion 72, and the lubricating oil flows toward the wall surface 40a of the housing 40 via the gutter portion 72. As a result, the lubricating oil can be supplied to the parts that require lubrication via the wall surface 40a of the housing 40 without extending the tube 48 to the vicinity of the parts that require lubrication, and the lubricating performance of the differential device 10 can be ensured without increasing the manufacturing cost.

The above describes in detail an embodiment of the present invention based on the drawings, but the present invention can also be applied in other aspects.

For example, in the above embodiment, the other end of the tube 48 is connected to the lubricating oil receiving passage 50, but this is not necessarily limited to this embodiment, and the connection destination of the other end of the tube 48 may be changed as appropriate.

In addition, in the above-mentioned embodiment, the lubricating oil discharged from the second discharge port 56 was configured to lubricate the bearing 38R by running down the rib 62, but the part requiring lubrication to which the lubricating oil is supplied is not limited to the bearing, and can be applied as appropriate to any part requiring lubrication, such as a gear.

Note that the above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

10: Differential device 12: Differential case 20: Differential mechanism 38R: Bearing (part requiring lubrication)
40: Housing 40a: Wall surface (wall surface of housing)
42: Lubricating device 48: Tube (lubrication piping)
56: Second discharge port (discharge port)
60: Baffle plate (member with a gutter portion formed therein)
62: Rib 72: Groove

Claims (1)

A lubrication device for a differential device that is applied to a differential device including a differential mechanism, a differential case that accommodates the differential mechanism, and a housing that rotatably supports the differential case via a bearing, the lubrication device being provided with a lubricating oil pipe through which lubricating oil is supplied, and configured to discharge the lubricating oil from a discharge port formed in the lubricating oil pipe.
The discharge port of the lubrication pipe is formed at a position for discharging the lubricating oil toward a wall surface of the housing,
A wall surface of the housing on which the lubricating oil discharged from the discharge port collides is formed with a rib for leading the lubricating oil that has collided with the wall surface of the housing along the wall surface to a portion that requires lubrication,
a member having a gutter portion formed therein, the gutter portion having a tip extending to the wall surface of the housing on which the rib is formed, is disposed below the discharge port when the lubricating oil is installed in the vehicle.

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