JP7267690B2 - Differential device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technical field of a differential device that is mounted on a vehicle such as an automobile and operates while the vehicle is running.

A vehicle such as an automobile is provided with a power transmission device for transmitting power from an engine, an electric motor, or the like to drive wheels, and the power output from the power transmission device is transmitted to the drive wheels via a differential device.

A differential device has a housing that accommodates required parts inside and a differential gear mechanism that is arranged inside the housing. A drive shaft to which power is transmitted and a drive gear fixed to one end of the drive shaft are arranged inside the housing, and the drive gear is meshed with a ring gear.

When the vehicle is traveling straight ahead, the road surface resistance to the left and right driving wheels is the same, so the differential case, which rotates together with the ring gear, causes the pinion gear to revolve, and the left and right side gears meshing with the pinion gear transmit the rotational force of the pinion gear. is transmitted. At this time, the pinion gear revolves without rotating.

On the other hand, when the vehicle turns, the resistance from the road surface to the left and right drive wheels is different, and one side gear tries to push back the pinion gear, causing the pinion gear to revolve and rotate. Therefore, the rotation of the pinion gear accelerates the rotation of the other side gear, and a difference in rotation is generated between the left and right drive wheels, ensuring smooth running.

As described above, in the differential device, necessary parts such as gears are arranged inside the housing, and lubricating oil is stored inside the housing for lubricating each part. The lubricating oil is sprung up by the ring gear, and by being sprung up, it flows toward each part inside the housing, and each part is lubricated by the flowed lubricating oil (see, for example, Patent Documents 1 and 2).

In the differential device disclosed in Patent Document 1, a rectifying plate is provided inside the housing, and the lubricating oil splashed up is guided in a predetermined direction by the rectifying plate so as to ensure a good lubricating state. there is

Further, in the differential device described in Patent Document 2, ribs are provided inside the housing, lubricating oil flowing along the side surface of the ring gear is dammed by the ribs, and the dammed lubricating oil flows in a predetermined direction. It is made to flow to ensure a good lubrication state.

Japanese Patent Application Laid-Open No. 2006-200730 JP 2011-21656 A

As described above, in the differential devices described in Patent Document 1 and Patent Document 2, it is possible to ensure a good lubricating state for each part with lubricating oil by providing a rectifying plate and ribs, but in a vehicle Since the state of the lubricating oil splashed by the ring gear changes depending on the traveling speed, it is necessary to ensure a good lubricating state for each part with the lubricating oil regardless of the traveling speed of the vehicle.

On the other hand, when the differential gear mechanism is in operation, power is transmitted from the engine or the like to each part arranged inside the housing, and each part such as the ring gear rotates. A torsional moment may be generated in the differential, and vibration may occur in the differential. Therefore, it is desirable to increase the strength of the housing to improve the torsional rigidity and suppress the occurrence of vibration.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the above-described problems, ensure good lubrication of each part with lubricating oil regardless of the running speed of the vehicle, and increase the strength of the housing.

First, a differential device according to the present invention is a differential device in which a differential gear mechanism is arranged inside a housing, wherein the differential gear mechanism is a ring gear rotated by power transmitted through a drive gear. and a differential case that rotates integrally with the ring gear, wherein the housing includes a cover portion that covers the differential gear mechanism, and a first rib and a second rib projecting downward from the inner surface of an upper portion of the cover portion, respectively. The first rib and the second rib are separated from each other on the left and right with respect to the position directly above the ring gear, and the upper part of the cover portion is positioned directly above the ring gear. A third rib protruding downward from the inner surface of the third rib is provided, and both left and right ends of the third rib are connected to the first rib and the second rib, respectively, and are connected to the outer peripheral edge of the third rib. Neither the boundary portion with the outer peripheral edge of the first rib nor the boundary portion between the outer peripheral edge of the third rib and the outer peripheral edge of the second rib is formed with an angular shape, and the first rib The outer peripheral edge of the third rib, the outer peripheral edge of the third rib, and the outer peripheral edge of the second rib are formed in a continuous curved shape , and the outer peripheral edge of the third rib is a concave curve in the projecting direction from the cover part It is formed in a shape .

As a result, the first rib and the second rib function as reinforcing ribs that reinforce the housing, and at least part of the lubricating oil splashed by the ring gear passes between the first rib and the second rib. A portion of the liquid is blocked by the first rib and the second rib by an amount corresponding to the rotation speed of the ring gear and flows downward along the first rib and the second rib.

Thereby, the first rib, the third rib, and the second rib are continuously provided in the left-right direction.

As a result, the third rib is formed into a shape in which stress concentration is less likely to occur.

Secondly , in the differential device according to the present invention described above, the outer peripheral edge of the first rib and the outer peripheral edge of the second rib are formed in a convex curved shape in the projecting direction from the cover portion. is desirable.

As a result, the widths of the first rib and the second rib in the projecting direction from the cover portion are increased.

Thirdly , in the above-described differential device according to the present invention, the ring gear is positioned to the left or right of the reference line when the center line of the housing in the left-right direction is set as a reference line. The first rib is positioned on the side of the reference line on which the ring gear is positioned, and the maximum amount of downward protrusion of the second rib from the upper portion is the maximum downward protrusion of the first rib from the upper portion. is preferably larger than the maximum amount of protrusion of

As a result, the maximum amount of projection of the second rib located on the wide side of the internal space of the cover portion relative to the ring gear in the left-right direction is made larger than the maximum amount of projection of the first rib located on the narrow side of the internal space. be.

Fourthly , in the differential device according to the present invention, the outer peripheral edge of the first rib and the outer peripheral edge of the second rib are inclined so as to be displaced downward as they are separated from each other in the left-right direction. is desirable.

As a result, the lubricating oil splashed up by the ring gear and dammed up by the first rib and the second rib travels downward and left and right along the outer peripheral edge of the first rib and the outer peripheral edge of the second rib. Fall.

Fifth , in the above-described differential device according to the present invention, it is desirable that the first rib and the second rib are positioned forward of the rotation shaft of the ring gear.

As a result, the lubricating oil splashed up by the ring gear is blocked by the first rib and the second rib positioned forward of the rotating shaft of the ring gear, so that the flow of the lubricating oil to the front side of the ring gear is blocked. hard.

Sixthly , in the above-described differential device according to the present invention, the housing is provided with a pair of side portions that are continuous with both left and right ends of the upper portion, and the first rib extends from the inner surface of the upper portion to one of the two side portions. It is desirable that the inner surface of the side portion is continuous and the second rib is continuous from the inner surface of the upper portion to the inner surface of the other side portion.

As a result, the first rib and the second rib are connected to the upper portion and the side portion at positions extending from the upper portion to the side portion.

According to the present invention, the first rib and the second rib function as reinforcing ribs that reinforce the housing, and at least a portion of the lubricating oil splashed up by the ring gear is displaced between the first rib and the second rib. A portion of the fluid passing through the ring gear is dammed by the first rib and the second rib in an amount corresponding to the rotation speed of the ring gear, and flows downward along the first rib and the second rib. It is possible to ensure a good lubricating state for each part with lubricating oil regardless of the speed, and to increase the strength of the housing.

FIG. 2 to FIG. 8 show an embodiment of the differential device of the present invention, and show a schematic configuration of a vehicle. 1 is a horizontal cross-sectional view of a differential device; FIG. FIG. 2 is a perspective view of a differential device with a part cut away; 1 is a plan view of a differential device; FIG. FIG. 4 is a conceptual diagram showing a positional relationship between a reinforcing wall and a ring gear; FIG. 4 is a cross-sectional view showing a state in which lubricating oil is splashed; FIG. 4 is a conceptual diagram showing the state of lubricating oil, etc. during low-speed running; FIG. 2 is a conceptual diagram showing the state of lubricating oil, etc. during high-speed running;

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for implementing the differential gear of the present invention will be described below with reference to the accompanying drawings.

<Vehicle configuration>
First, an overview of the configuration of a vehicle 100 including a differential device will be described (see FIG. 1).

The vehicle 100 includes an engine 101 , a power transmission device 102 , a hydraulic control section 103 , a gear mechanism 104 , a differential device 1 , driving wheels 105 , 105 , an engine control section 106 , a transmission mechanism control section 107 and a bus 108 .

The engine 101 functions as a power source (motor) for running the vehicle 100 , consumes fuel, and generates power to act on the drive wheels 105 , 105 of the vehicle 100 . Engine 101 combusts fuel to produce torque on crankshaft 109 which acts as an output shaft to driveline 102 . In vehicle 100, an electric motor may be provided as a drive source for running in place of or in addition to engine 101. FIG.

The power transmission device 102 has a torque converter 110 , a forward/reverse switching mechanism 111 and a speed change transmission mechanism 112 . The power transmission device 102 is provided in a power transmission path from the engine 101 to the driving wheels 105, 105, has a function of transmitting power from the engine 101 to the driving wheels 105, 105, and is operated by hydraulic oil pressure.

The torque converter 110 is arranged between the engine 101 and the forward/reverse switching mechanism 111 and has a function of amplifying or maintaining the torque of power transmitted from the engine 101 via the crankshaft 109 and transmitting it to the forward/reverse switching mechanism 111 . are doing.

The forward/reverse switching mechanism 111 is arranged between the torque converter 110 and the speed change transmission mechanism 112, and has a function of changing the rotation speed of a rotating shaft rotated by power transmitted from the engine 101 via the torque converter 110, and a function of changing the rotation speed of the rotating shaft. It has a function of switching the direction of rotation.

The transmission transmission mechanism 112 is arranged between the forward/reverse switching mechanism 111 and the gear mechanism 104 . Power is transmitted from the forward/reverse switching mechanism 111 to the transmission transmission mechanism 112 via the input shaft 113, and the power input from the transmission transmission mechanism 112 via the input shaft 113 is directed to the gear mechanism 104 via the output shaft 114. output as The speed change transmission mechanism 112 has a continuously variable transmission (CVT) that continuously changes the speed of the power input through the input shaft 113 .

The power transmitted from transmission transmission mechanism 112 to output shaft 114 is transmitted to differential device 1 via gear mechanism 104 . Differential device 1 transmits the transmitted power to driving wheels 105, 105 via axles 115, 115. As shown in FIG. The differential device 1 has a function of absorbing a difference in rotational speed between the drive wheels 105, 105 that occurs when the vehicle 100 turns.

The hydraulic control unit 103 operates the torque converter 110, the forward/reverse switching mechanism 111, and the shift transmission mechanism 112 by the hydraulic pressure of the hydraulic oil. The hydraulic control unit 103 is provided with a plurality of oil passages, an oil reservoir, an oil pump, a plurality of solenoid valves, etc. (not shown), and supplies power to each unit of the power transmission device 102 based on control signals output from the transmission mechanism control unit 107. It controls the flow rate and hydraulic pressure of the hydraulic oil used. The hydraulic control unit 103 also functions as a lubricating oil supply unit that lubricates each part of the power transmission device 102 and each part of the differential device 1 .

The engine control unit 106 and the transmission mechanism control unit 107 are equipped with a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. They are connected for mutual data communication via a bus 108 conforming to the in-vehicle network communication standard.

The engine control unit 106 has a function of performing various operation controls such as fuel injection control, ignition control, and intake air amount adjustment control for the engine 101 . The engine control unit 106 is enabled to communicate with the transmission mechanism control unit 107, outputs data regarding the operating state of the engine 101 to the transmission mechanism control unit 107 as necessary, and outputs data from the transmission mechanism control unit 107 as necessary. The operation of the engine 101 is controlled based on various signals received.

The transmission mechanism control unit 107 controls the operation of the torque converter 110 , the forward/reverse switching mechanism 111 and the speed change transmission mechanism 112 by controlling the hydraulic pressure control unit 103 .

<Configuration of Differential Device>
Next, the configuration of the differential device 1 will be described (see FIGS. 2 to 6).

The differential device 1 is constructed by disposing or supporting required parts in a housing 2 (see FIGS. 2 and 3).

The housing 2 has a cylindrical shaft support portion 3 extending in the front-rear direction and a cover portion 4 connected to the rear end of the shaft support portion 3. The inner space of the cover portion 4 is formed as an arrangement space 4a. there is The cover part 4 has an upper part 5 , a lower part 6 , side parts 7 , 8 and a rear part 9 .

The upper portion 5 has an upper surface portion 5a that faces in a substantially vertical direction and an inclined surface portion 5b that is positioned on the front side of the upper surface portion 5a and inclined so as to be displaced downward as it goes forward, and the upper surface portion 5a and the inclined surface portion 5b are continuous. is provided. The upper portion 5 is connected to the rear end of the shaft support portion 3 at the front end of the inclined surface portion 5b. Mounting holes 7a and 8a are formed through the side portions 7 and 8, respectively.

The housing 2 is provided with, for example, a plate-like reinforcing wall 10 protruding downward from the inner surface 5c of the upper portion 5 (see FIGS. 4 and 5). For example, the reinforcing wall 10 protrudes downward from the upper surface portion 5a, but may protrude downward from the inclined surface portion 5b. The reinforcing wall 10 is composed of a first rib 11, a second rib 12 and a third rib 13. The first rib 11 and the second rib 12 are separated from each other with the third rib 13 interposed therebetween. is located. The reinforcing wall 10 does not have to be provided with the third ribs 13 . In this case, the reinforcing wall 10 is composed of the first ribs 11 and the second ribs 12 .

The first rib 11 is positioned to the left of the third rib 13 and is continuous with the third rib 13 in the left-right direction. The second rib 12 is positioned to the right of the third rib 13 and is third in the left-right direction. It is continuous with three ribs 13 . The first rib 11 is provided continuously from the inner surface 5c of the upper portion 5 to the upper end portion of the inner surface 7b of the left side portion 7, and the second rib 12 is provided continuously from the inner surface 5c of the upper portion 5 to the right side portion 8. It is continuously provided at a position extending over the upper end portion of the inner surface 8b.

In the differential device 1, if the center line of the housing 2 in the lateral direction is a reference line M, the third rib 13 is positioned to the left of the reference line M, for example. Therefore, the first rib 11 is located to the left of the reference line M, and the second rib 12 is located to the right of the third rib 13 at a position including the reference line M.

The first rib 11 is formed in such a shape that the amount of downward protrusion from the upper portion 5 increases with increasing distance from the third rib 13 in the left-right direction. It is curved. The second rib 12 is formed in such a shape that the amount of downward protrusion from the upper portion 5 increases as the distance from the third rib 13 increases in the left-right direction. It is curved. The maximum downward protrusion amount H2 from the upper portion 5 of the second rib 12 is set larger than the maximum protrusion amount H1 from the upper portion 5 of the first rib 11 . The lateral width of the second rib 12 is made larger than the lateral width of the first rib 11 .

The third rib 13 projects downward from the upper portion 5 by a smaller amount than the downward projection amounts of the first rib 11 and the second rib 12, and the outer peripheral edge 13a is formed in a curved shape concave downward. ing.

The outer peripheral edge 13a of the third rib 13 is smoothly connected to the outer peripheral edge 11a of the first rib 11 and the outer peripheral edge 12a of the second rib 12. No angular shape is formed in both boundary portions of the boundary portion between the peripheral edge 13a and the outer peripheral edge 12a. Therefore, stress concentration is less likely to occur at the boundary portion between the third rib 13 and the first rib 11 and the boundary portion between the third rib 13 and the second rib 12, and high strength of the housing 2 can be ensured. be.

Bearing members 14, 14 are fixed to the side portions 7, 8 of the housing 2, respectively (see FIGS. 2 and 3). The bearing members 14 , 14 are fixed to the side portions 7 , 8 with parts thereof inserted through the mounting holes 7a , 8a .

Shaft coupling members 15, 15 are rotatably supported by the bearing members 14, 14 via bearings, respectively. An axle 115 is connected to the shaft connecting member 15 .

A drive shaft 16 is rotatably supported by the shaft support portion 3 of the housing 2 via bearings. Power from the engine 101 and the like is transmitted to the drive shaft 16 via a gear mechanism 104 .

A drive gear 17 is fixed to the rear end of the drive shaft 16 . The drive gear 17 is positioned in the arrangement space 4 a of the cover portion 4 in the housing 2 and rotates together with the drive shaft 16 .

A differential gear mechanism 18 is arranged in the arrangement space 4 a of the cover portion 4 . The differential gear mechanism 18 has a ring gear 19, a differential case 20, pinion gears 21, 21 and side gears 22, 22. As shown in FIG.

The ring gear 19 has a rotating shaft 19a whose axial direction is the left-right direction, and meshes with the drive gear 17 at the front end thereof. The ring gear 19 is positioned to the left of the reference line M and directly below the third rib 13 on the reinforcing wall 10 provided in the housing 2 (see FIG. 5). Therefore, the third rib 13 is positioned just above the ring gear 19 .

A rotating shaft 19 a of the ring gear 19 is positioned behind the first rib 11 and the second rib 12 . Therefore, the first rib 11 and the second rib 12 are positioned forward of the rotating shaft 19a of the ring gear 19. As shown in FIG.

A ring gear 19 is fixed to the differential case 20 (see FIGS. 2 and 3). Therefore, the ring gear 19 and the differential case 20 are rotated together. The internal space of the differential case 20 is formed as a gear arrangement space 20a, and both sides of the differential case 20 are formed with gear support holes 20b, 20b, respectively. Parts of the shaft connecting members 15, 15 are inserted through the gear support holes 20b, 20b of the differential case 20, respectively, and the inner ends of the shaft connecting members 15, 15 are positioned in the gear arrangement space 20a.

A gear support shaft 23 is fixed to the differential case 20 . The gear support shaft 23 is axially oriented in the front-rear direction and is positioned between the front and rear surfaces of the differential case 20 .

The pinion gears 21 , 21 are rotatably supported by a gear support shaft 23 and positioned in a gear arrangement space 20 a of the differential case 20 . The pinion gears 21, 21 are supported on both ends of the gear support shaft 23 in the axial direction.

The side gears 22, 22 are positioned in the gear arrangement space 20a while being fixed to the inner ends of the shaft connecting members 15, 15, respectively, and mesh with both the two pinion gears 21, 21, respectively. The side gears 22, 22 are partially inserted into the gear support holes 20b, 20b of the differential case 20, respectively, and are rotated integrally with the shaft coupling members 15, 15 with respect to the differential case 20, respectively.

Lubricating oil 50 is stored in the interior of the housing 2, particularly in the space below the interior of the cover portion 4 (see FIG. 6). Therefore, the lower space inside the cover portion 4 serves as a storage space 4 b for storing the lubricating oil 50 . The lubricating oil 50 plays a role of lubricating each part arranged inside the housing 2, is sprung up by the rotation of the ring gear 19, and flows toward each part.

<Operation in Differential Device>
The operation of the differential gear mechanism 18 and the like in the differential device 1 will be described below.

When power from the engine 101 or the like is transmitted to the drive gear 17 via the drive shaft 16, the ring gear 19 meshing with the drive gear 17 is rotated, and the ring gear 19 and the differential case 20 are rotated integrally. At the same time, the pinion gears 21, 21 revolve as the differential case 20 rotates. When the pinion gears 21, 21 revolve, the side gears 22, 22 meshing with the pinion gears 21, 21 are rotated, the side gears 22, 22 and the shaft connecting members 15, 15 are rotated integrally, and the axles 115, 115 are rotated. The power is transmitted to the drive wheels 105, 105 via and the vehicle 100 runs.

At this time, when the vehicle 100 is traveling straight ahead, the resistance from the road surface to the left and right drive wheels 105, 105 is the same. , 21 are equally transmitted to the side gears 22 , 22 .

On the other hand, when the vehicle 100 turns, the resistance from the road surface to the left and right drive wheels 105, 105 is different, and the side gear 22 on one side tries to push back the pinion gears 21, 21, causing the pinion gears 21, 21 to revolve and rotate. Therefore, the rotation of the other side gear 22 is accelerated by the rotation of the pinion gears 21, 21, and a difference in rotation is generated between the left and right drive wheels 105, 105, ensuring smooth running.

As described above, when the vehicle 100 travels (forwards), the ring gear 19 is rotated and the lubricating oil 50 is splashed up by the ring gear 19 (see FIG. 6).

At this time, when the speed of the vehicle 100 is low, the rotation speed of the ring gear 19 is also low, so the lubricating oil 50 is mainly splashed up to the position directly above the ring gear 19 (see FIG. 7).

A third rib 13 is positioned right above the ring gear 19, and a space 24 is formed between the first rib 11 and the second rib 12, so that the splashed lubricating oil 50 is Head to the front side of the reinforcing wall 10 through the space 24 except for the part. The lubricating oil 50 directed toward the front side of the reinforcing wall 10 lubricates the drive gear 17 and the like, flows into the storage space 4b, is bounced up again by the ring gear 19, and is circulated.

Also, part of the lubricating oil 50 that has been splashed up is mainly blocked by the third ribs 13 and falls along the rear surfaces of the third ribs 13, the first ribs 11, and the second ribs 12. Then, the oil lubricates the differential gear mechanism 10 and the like, flows into the storage space 4b, is sprung up again by the ring gear 19, and is circulated. At this time, the outer peripheral edge 11a of the first rib 11 and the outer peripheral edge 12a of the second rib 12 are inclined so as to be displaced downward as they are separated from each other in the left-right direction. It falls along the outer peripheral edge 12a downward and to the left and right.

On the other hand, when the speed of the vehicle 100 is high, the rotational speed of the ring gear 19 is also high. See Figure 8). When the speed of the vehicle 100 is high, the lubricating oil 50 splashed to the position right above the ring gear 19 spreads over a wide range to the left and right compared to when the vehicle 100 is traveling at a low speed.

Since the third rib 13 is positioned directly above the ring gear 19 and the space 24 is formed between the first rib 11 and the second rib 12, the lubricating oil splashed up 50 goes to the front side of the reinforcing wall 10 through the space 24 except for a part. The lubricating oil 50 directed toward the front side of the reinforcing wall 10 lubricates the drive gear 17 and the like, flows into the storage space 4b, is bounced up again by the ring gear 19, and is circulated.

Also, part of the lubricating oil 50 splashed up is blocked by the first rib 11, the second rib 12 and the third rib 13, and the first rib 11 and the second rib 12 The oil falls downward along the rear surface of the third rib 13, lubricates the differential gear mechanism 10 and the like, flows into the storage space 4b, is flipped up again by the ring gear 19, and is circulated. At this time, the lubricating oil 50 falls along the outer peripheral edge 11a and the outer peripheral edge 12a downward and left and right.

Furthermore, the amount of the lubricating oil 50 splashed to the right of the ring gear 19 is larger than that of the lubricating oil 50 that is splashed straight up, and most of it is below the second rib 12. It goes to the front side of the reinforcing wall 10 through the space 25. - 特許庁The lubricating oil 50 directed toward the front side of the reinforcing wall 10 lubricates the drive gear 17 and the like, flows into the storage space 4b, is bounced up again by the ring gear 19, and is circulated.

As described above, when the speed of the vehicle 100 is high, the lubricating oil 50 splashed to the position right above the ring gear 19 spreads widely in the left and right direction, and the ring gear It is easy to jump up to the right of 19. Therefore, in the differential device 1, the positions and sizes of the first rib 11, the second rib 12, and the third rib 13 are determined according to both the low speed case and the high speed case. A third rib 13 having the smallest amount of downward protrusion from the upper portion 5 is positioned right above the ring gear 19, and a first rib 11 and a second rib 12 are provided on both sides of the third rib 13. The outer peripheral edge 11a and the outer peripheral edge 12a are formed in a curved shape inclined so as to be displaced downward as they are separated from each other in the left-right direction. It is formed in a size that does not dam up more than necessary.

A space 24 is formed directly above the ring gear 19 where the amount of the lubricating oil 50 splashed up is the largest, and a space 25 is also formed to the right of the ring gear 19 where a large amount of the lubricating oil 50 is splashed up during high speed running. Therefore, a sufficient amount of lubricating oil 50 flows forward through the space 24 and the space 25, and it is possible to ensure a good lubricating state for each part located in front of the ring gear 19.

<Summary>
As described above, in the differential device 1, the housing 2 includes the cover portion 4 that covers the operating gear mechanism 18, and the first rib 11 and the first rib 11 that protrude downward from the inner surface of the upper portion 5 of the cover portion 4, respectively. 2 ribs 12 are provided, and the first rib 11 and the second rib 12 are positioned so as to be separated from each other to the left and right with respect to the position directly above the ring gear 19 .

Therefore, the first rib 11 and the second rib 12 function as reinforcing ribs for reinforcing the housing 2, and at least a portion of the lubricating oil 50 splashed by the ring gear 19 is absorbed by the first rib 11 and the second rib 12. 12, a part of it is dammed by the first rib 11 and the second rib 12 by an amount corresponding to the rotation speed of the ring gear 19, and travels downward along the first rib 11 and the second rib 12. flowed. As a result, regardless of the traveling speed of the vehicle 100, the lubricating oil 50 can ensure a good lubricating state for each part, and the strength of the housing 2 can be increased.

A third rib 13 projecting downward from the inner surface of the upper portion 5 of the cover portion 4 is provided at a position directly above the ring gear 19. 2 ribs 12.

Therefore, since the first rib 11, the third rib 13, and the second rib 12 are continuously provided in the left-right direction, the strength of the housing 2 is further increased, and the differential gear mechanism 10 can be stably operated. can do.

Furthermore, the outer peripheral edge 11a of the first rib 11 and the outer peripheral edge 12a of the second rib 12 are formed in a convex curved shape in the projecting direction from the cover portion 4 .

Therefore, the widths of the first ribs 11 and the second ribs 12 in the projecting direction from the cover portion 4 are increased, thereby improving the strength of the housing 2 and improving the degree of freedom in controlling the lubricating oil 50. be able to.

Furthermore, the outer peripheral edge 13a of the third rib 13 is formed in a concave curved shape in the projecting direction from the cover portion 4. As shown in FIG.

Therefore, since the third ribs 13 are formed in a shape in which stress concentration is less likely to occur, the strength of the third ribs 13 increases, and the strength of the housing 2 can be improved.

Further, the housing 2 is formed by, for example, metal casting, and the reinforcing wall 10 is formed by extracting a core inserted inside the mold. Since the core is a thin sand mold, there is a possibility that it may be partially damaged when it is taken out. Problems remaining between the rib 11 and the second rib 12 are less likely to occur, and high molding precision of the housing 2 can be ensured, and breakage of the core can be prevented.

Further, the ring gear 19 is positioned to the left of the reference line M of the housing 2, the first rib 11 is positioned on the side of the reference line M in the horizontal direction where the ring gear 19 is positioned, and the upper portion of the second rib 12 is positioned. The maximum downward protrusion amount H2 from the upper portion 5 of the first rib 11 is set larger than the maximum downward protrusion amount H1 from the upper portion 5 of the first rib 11 .

Therefore, the maximum projection amount H2 of the second rib 12 located on the wide space side of the internal space 4a of the cover portion 4 with respect to the ring gear 19 in the left-right direction is the maximum projection amount H2 of the first rib 11 located on the narrow space side. Since the protruding amount is larger than H1, it is possible to improve the strength of the housing 2 while ensuring a good circulation state of the lubricating oil 50 splashed up by the rotation of the ring gear 19 .

In the above example, the ring gear 19 is positioned to the left of the reference line M of the housing 2, but the ring gear 19 may be positioned to the right of the reference line M of the housing 2. In this case, the positions of the first rib 11 and the second rib 12 are reversed in the horizontal direction.

Further, the outer peripheral edge 11a of the first rib 11 and the outer peripheral edge 12a of the second rib 12 are inclined so as to be displaced downward as they are separated from each other in the left-right direction.

Therefore, the lubricating oil 50, which has been splashed up by the ring gear 19 and blocked by the first rib 11 and the second rib 12, runs down and left and right along the outer peripheral edge 11a and the outer peripheral edge 12a and falls. Inside, the lubricating oil 50 is lubricated over a wide range in the left-right direction, and a good lubricating state for each part arranged inside the housing 2 can be ensured.

Furthermore, the first rib 11 and the second rib 12 are positioned forward of the rotating shaft 19 a of the ring gear 19 .

Therefore, since the lubricating oil 50 splashed up by the ring gear 19 is blocked by the first rib 11 and the second rib 12 positioned in front of the rotation shaft 19a of the ring gear 19, the lubrication to the front side of the ring gear 19 is prevented. The flow of the oil 50 is less likely to be hindered, and the lubricating oil 50 is allowed to sufficiently flow to the front side of the ring gear 19 to ensure a good lubricating state for each part.

In addition, a first rib 11 extends from the inner surface 5c of the upper portion 5 to the inner surface 7b of the side portion 7, and a second rib 12 extends from the inner surface 5c of the upper portion 5 to the inner surface 8b of the side portion 8. ing.

Therefore, since the first rib 11 and the second rib 12 are continuous with the upper portion 5 and the side portions 7 and 8 at positions extending from the upper portion 5 to the side portions 7 and 8, the upper portion 5 and the side portions 7 and 8 of the housing 2 are connected. 8 are reinforced by the first rib 11 and the second rib 12, so that the strength of the housing 2 can be further improved.

DESCRIPTION OF SYMBOLS 1... Differential apparatus 2... Housing 4... Cover part 5... Upper part 5c... Inner surface 7... Side part 7b... Inner surface 8... Side part 8b... Inner surface 11... First rib 11a... Outside Peripheral edge 12... Second rib 12a... Outer peripheral edge 13... Third rib 13a... Outer peripheral edge 17... Drive gear 18... Differential gear mechanism 19... Ring gear 19a... Rotating shaft 20... Differential Case

Claims (8)

A differential device in which a differential gear mechanism is arranged inside a housing,
The differential gear mechanism includes a ring gear rotated by power transmitted through a drive gear and a differential case rotated integrally with the ring gear,
the housing includes a cover portion that covers the differential gear mechanism, and a first rib and a second rib projecting downward from an inner surface of an upper portion of the cover portion,
The first rib and the second rib are separated from each other to the left and right with respect to a position directly above the ring gear,
A third rib protruding downward from the inner surface of the upper portion of the cover portion is provided at a position directly above the ring gear,
both left and right ends of the third rib are connected to the first rib and the second rib, respectively;
Both the boundary portion between the outer peripheral edge of the third rib and the outer peripheral edge of the first rib and the boundary portion between the outer peripheral edge of the third rib and the outer peripheral edge of the second rib have an angular shape. not formed,
The outer peripheral edge of the first rib, the outer peripheral edge of the third rib, and the outer peripheral edge of the second rib are formed in a continuous curved shape ,
An outer peripheral edge of the third rib is formed in a concave curved shape in a projecting direction from the cover portion.
Differential device. An outer peripheral edge of the first rib and an outer peripheral edge of the second rib are formed in a convex curved shape in a projecting direction from the cover portion.
2. A differential device according to claim 1 . The ring gear is positioned to the left or right of the reference line when the central line of the housing in the left-right direction is set as a reference line,
The first rib is positioned on the side of the reference line in the left-right direction on which the ring gear is positioned,
The maximum amount of downward protrusion of the second rib from the top is larger than the maximum amount of downward protrusion of the first rib from the top.
The differential device according to claim 1 or 2 . The outer peripheral edge of the first rib and the outer peripheral edge of the second rib are inclined so as to be displaced downward as they are separated from each other in the left-right direction.
A differential device according to any one of claims 1 to 3 . The first rib and the second rib are positioned forward of the rotating shaft of the ring gear.
A differential device according to any one of claims 1 to 4 . The housing is provided with a pair of side portions that are continuous with both left and right ends of the upper portion,
the first rib is continuous from the inner surface of the upper portion to the inner surface of one of the side portions;
The second rib is continuous from the inner surface of the upper portion to the inner surface of the other side portion.
A differential device according to any one of claims 1 to 5 . The ring gear is meshed with the drive gear on one side in the left-right direction,
The second rib is positioned on the side where the ring gear and the drive gear are meshed.
A differential device according to any one of claims 1 to 6. The first rib, the second rib, and the third rib are formed in a plate shape,
A first space is formed between the first rib and the second rib on the upper side of the ring gear,
A second space is formed below the second rib
A differential device according to any one of claims 1 to 7.

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