speed reduction device

Abstract

To provide a speed reducer capable of improving fuel economy by reducing the stirring resistance of lubricating oil while securing the lubricating oil scooped up by a gear.SOLUTION: A speed reducer 1 includes a rotary body supported at both ends by a first bearing 41 and a second bearing 42, a first gear 2 arranged near the first bearing 41 and adapted to be rotated integrally with the rotary body, and a casing including the first bearing 41, the second bearing 42, the rotary body, and the first gear 2, the casing having a partition wall for partitioning from each other a first space 51 protruding from an internal bottom face 5c while being directed to the rotary body 4, and opposed to a tooth part 2a of the first gear 2, where at least parts of the first bearing 41 and the first gear 2 are arranged, and a second space 52 where at least part of the second bearing 42 is arranged.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a speed reducer.

Background Art

[0002] In a speed reducer such as a final speed reducer mounted on a vehicle, gears and bearings that rotate at high speed and transmit high power are arranged. Therefore, a certain amount of lubricating oil is filled inside a housing that covers the gears and bearings for lubrication and cooling purposes (see, for example, Patent Document 1).

[0003] As in the power transmission device described in Patent Document 1, a bevel gear with a large outer diameter is used for the ring gear of the final speed reducer. The housing that houses the ring gear is formed such that the vertical lower part of the ring gear is the lowest part. The lubricating oil filled in the housing stays at the lowest part inside the housing.

[0004] When the vehicle runs, the lubricating oil in the housing is scraped up by the ring gear and supplied to bearings, gear meshing parts where gears mesh, etc. for lubrication. The lubricating oil that lubricates the gear meshing part between the drive pinion gear and the ring gear and the bearings that support the drive pinion gear and the differential transmission mechanism returns to the lowest part of the housing.

[0005] All the locations that require lubrication are arranged at positions separated from the ring gear. Therefore, the power transmission device described in Patent Document 1 provides an oil guide for guiding lubricating oil in order to appropriately lubricate each part that requires lubrication.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in a reduction gear, if there is insufficient lubricating oil remaining at the bottom of the carrier, there will be insufficient lubricating oil to lubricate the bearings. If an excessive amount of lubricating oil is filled in an attempt to avoid this, the ring gear will agitate the oil surface, leading to an increase in agitation resistance and a deterioration in fuel efficiency.

[0008] To resolve this problem, it is necessary to ensure that the required amount of lubricating oil is reliably supplied to the areas that need lubrication, while preventing excessive amounts of lubricating oil from accumulating at the bottom of the carrier.

[0009] This invention was created to solve these problems, and aims to provide a reduction gear that can improve fuel efficiency by reducing the stirring resistance of the lubricating oil while ensuring that the lubricating oil is stirred up by the gears. [Means for solving the problem]

[0010] To solve the aforementioned problems, the reduction gear according to the present invention comprises a rotating body supported at both ends by a first bearing and a second bearing, a first gear disposed near the first bearing and rotating integrally with the rotating body, and a housing that encloses the first bearing, the second bearing, the rotating body, and the first gear and has an oil reservoir at its bottom for storing lubricating oil, wherein the housing has a partition wall that protrudes from its internal bottom surface toward the rotating body and faces the teeth of the first gear, and partitions a first space in which at least a part of the first bearing and the first gear are disposed, and a second space in which at least a part of the second bearing is disposed, and the rotating body has the first gear and the second bearing between them. The rotating body has a center of rotation, a hollow spherical shell having an opening formed on the outer circumference of the rotating body, a gear housing chamber for housing a pinion gear and a side gear, and a helical groove formed on the inner surface of a cylindrical boss portion into which the first bearing and the second bearing are fitted, for guiding lubricating oil that has flowed down from the inner wall of the housing to the sides of the first bearing and the second bearing into the gear housing chamber. The lubricating oil from the oil reservoir, scraped up by the first gear, comes into contact with the ceiling surface of the housing, flows down from the inner wall of the housing to the sides of the first bearing and the second bearing, flows into the rotating body through the helical groove, lubricates the meshing and sliding parts of the pinion gear and the side gear, and is discharged from the opening into the oil reservoir. The housing is composed of a first housing and a second housing divided by a joint surface passing through the rotation center of the rotating body, the partition wall consists of a first partition wall formed in the first housing and a second partition wall formed in the second housing, the first partition wall and the second partition wall are connected by the joint surface, at least one of the first partition wall and the second partition wall has a flow path communicating with the first space and the second space, the flow path consists of a notched groove formed in at least one of the joint surface of the first partition wall and the joint surface of the second partition wall, the flow path is provided with a valve that opens and closes in accordance with fluctuations in oil temperature, the valve is an on / off valve comprising a valve body that opens and closes the flow path and a valve body support member that is fixed to the base end of the valve body and attached so as to sandwich the joint surface of the first partition wall or the second partition wall . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a reduction gear that can improve fuel efficiency by reducing the stirring resistance of the lubricating oil while ensuring that the lubricating oil is stirred up by the gears. [Brief explanation of the drawing]

[0012] [Figure 1] This is a longitudinal cross-sectional view showing a reduction gear according to the first embodiment of the present invention. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 1. [Figure 4]It is a cross-sectional view taken along line IV-IV of FIG. 1. [Figure 5] It is a longitudinal sectional view showing a speed reduction device according to a second embodiment of the present invention. [Figure 6] It is a cross-sectional view taken along line VI-VI of FIG. 5. [Figure 7] It is a view showing a speed reduction device according to a third embodiment of the present invention, and is a cross-sectional view of a main part showing the installation state of a flow path. [Figure 8] It is a view showing a speed reduction device according to a fourth embodiment of the present invention, and is an enlarged cross-sectional view of a main part showing the installation state of a valve. [Figure 9] It is an enlarged cross-sectional view taken along line IX-IX of FIG. 8 and shows the installation state of a valve. [Figure 10] It is an enlarged cross-sectional view taken along line IX-IX of FIG. 8 and shows the state when the valve is opened.

Mode for Carrying Out the Invention

[0013] The speed reduction device 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the following description, the same elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0014] ≪Speed Reduction Device≫ As shown in FIG. 1, the speed reduction device 1 is a device for reducing the power generated by a prime mover (not shown) disposed in front of the vehicle and transmitted through a transmission. Hereinafter, as an example of the speed reduction device 1, a differential device (final reduction device) for differentially rotating the left and right rear wheels by the power transmitted through the propeller shaft will be described as an example. The speed reduction device 1 includes a ring gear 2 (first gear), a drive pinion gear 3 (second gear), a differential case 4 (rotating body), and a carrier 5 (housing) that houses the ring gear 2, the drive pinion gear 3, and the differential case 4.

[0015] ≪Ring Gear≫ As shown in Fig. 1, the ring gear 2 (first gear) is a gear that meshes orthogonally with the tooth portion 3a of the drive pinion gear 3 described below. The ring gear 2 is composed of an annular hypoid gear having a larger diameter than the drive pinion gear 3. As shown in Figs. 2 to 4, a flange portion 4c integrally formed with the differential case 4 is fixed to the left end portion in the axial direction of the ring gear 2. For this reason, the ring gear 2 rotates integrally with the differential case 4 around the axis O1. The ring gear 2 is disposed between the first bearing 41 and the second bearing 42.

[0016] <<Drive Pinion Gear>> As shown in Fig. 1, the drive pinion gear 3 (second gear) is a gear for transmitting the output from a transmission (not shown) to the ring gear 2. The drive pinion gear 3 is integrally formed with a tooth portion 3a and a drive pinion shaft 3b extending forward from the tooth portion 3a. The drive pinion shaft 3b is disposed along a direction orthogonal to the axis O1 - O1 (see Fig. 2) of the ring gear 2. The rear end portion of the drive pinion shaft 3b is disposed in the first housing 6 of the carrier 5 via the third bearings 31, 32 and the third space 53. [[ID= + 7]]

[0017] <Third Bearing> The third bearings 31, 32 are bearings that support the drive pinion shaft 3b of the drive pinion gear 3. The third bearings 31, 32 are disposed in the drive pinion shaft housing portion 69 of the first housing 6. A third space 53 for temporarily storing lubricating oil is formed between the third bearing 31 and the third bearing 32. Oil passages 33, 34 are formed in the third space 53.

[0018] <Oil Passage> As shown in Fig. 1, the oil passages 33, 34 are flow paths for circulating the lubricating oil in the third space 53 and the lubricating oil in the transmission mechanism portion housing portion 66 of the first housing 6. The oil passage 33 is located on the side of the hole in the carrier 5 into which the third bearing 32 is fitted, and when viewed from above, it opens in the radial direction of the ring gear 2, communicates with the third space 53, and is formed so that a portion of the lubricating oil scraped up by the ring gear 2 is guided into the third space 53 via the oil passage 33. The oil passage 34 communicates with the third space 53 and the oil reservoir 5b of the second space 52, and is formed to allow the lubricating oil in the third space 53 to flow into the second space 52. Therefore, the lubricating oil flows into the third space 53 through the oil passage 33, lubricates the third bearings 31 and 32, and is then discharged from the third space 53 through the oil passage 34 to the oil reservoir 5b in the second space 52.

[0019] ≪Diff Case≫ As shown in Figures 3 and 4, the differential case 4 (rotating body) is a gear case that houses a pinion shaft 43, a pinion gear 44 (see Figures 1 and 2), and side gears 45. The differential case 4 is supported at both its left and right ends by a first bearing 41 and a second bearing 42, and is pivotally supported so as to be rotatable about the axis O1-O1. The differential case 4 has a hollow spherical shell portion 4a, an opening 4b formed on the outer circumference of the spherical shell portion 4a, cylindrical boss portions 4d formed on both the left and right ends of the spherical shell portion 4a, and a flange portion 4c formed near the left end of the spherical shell portion 4a. Inside the differential case 4 are a pinion shaft 43 extending radially from the differential case 4, a pair of pinion gears 44 (see Figure 1) pivotally supported on the pinion shaft 43, and a pair of side gears 45 that mesh with the pinion gears 44. The differential case 4 is rotatably supported on the carrier 5 by its left and right boss portions 4d via a first bearing 41 and a second bearing 42.

[0020] <Spherical shell and gear storage chamber> The spherical shell portion 4a is a substantially cylindrical part that constitutes the gear housing chamber 4e, which rotatably houses the pinion gear 44 (see Figure 1) and the side gear 45. The spherical shell portion 4a has a plurality of openings 4b formed therein. The openings 4b can also be used as insertion holes when installing the pinion gear 44 and the side gear 45 inside the differential case 4.

[0021] <Flange section> As shown in Figures 3 and 4, the flange portion 4c is the part that fixes the ring gear 2 to the outer circumference of the differential case 4. The flange portion 4c is formed as an annular projection on the outer circumference of the spherical shell portion 4a.

[0022] <Boss section and spiral groove> The boss portion 4d is a cylindrical mounting area into which the first bearing 41 and the second bearing 42, which support the differential case 4, are fitted. The boss portion 4d is mounted on the differential case shaft support portion 5f via the first bearing 41 and the second bearing 42. A helical groove 4f is formed on the inner circumferential surface of the boss portion 4d, which serves as an oil passage to guide lubricating oil flowing down from the carrier 5 (described later) into the gear housing chamber 4e when the drive shaft 8 rotates in the forward rotation direction. The helical groove 4f is formed from the left and right open ends of the boss portion 4d to the seating surface on the back of the gear of the side gear 45.

[0023] Career As shown in Figure 2, the carrier 5 is a housing that encloses the first bearing 41, the second bearing 42, the differential case 4 (rotating body), the ring gear 2 (first gear), etc. The carrier 5 consists of a first housing 6 and a second housing 7, which are divided front and rear by a joint surface 5a passing through the rotation center O1 of the differential case 4. In other words, the carrier 5 is assembled as a single unit by fastening two case halves, the first housing 6 and the second housing 7, which are separable in a direction intersecting the axis of the drive shaft 8 passing through the axis O1 of the ring gear 2.

[0024] Inside the carrier 5 are the ring gear 2, the drive pinion gear 3, the differential case 4, the drive pinion shaft 3b, the first bearing 41, the second bearing 42, and the third bearings 31 and 32.

[0025] <Oil accumulation area> As shown in Figure 1, when the vehicle is stopped, the lubricating oil filled in the carrier 5 reaches an oil level of L1, and the oil is stored at a level where the lower end of the ring gear 2 and the lower end of the drive pinion gear 3 are submerged. When the vehicle is running, the lubricating oil is stirred up by the ring gear 2 and supplied to each part, so the oil level L2 drops to the same level as the upper surface of the first bulkhead 61. As shown in Figures 3 and 4, the oil reservoir 5b is divided into a first space 51 side and a second space 52 side by bulkheads (first bulkhead 61 and second bulkhead 71) formed slightly towards the ring gear 2 from approximately the center of the oil reservoir 5b.

[0026] <Ceiling surface> A lubricating oil receiving section 62 is formed in the upper front part of the carrier 5 to collect the lubricating oil scraped up by the ring gear 2 when the vehicle moves forward. The collected lubricating oil flows down the inner wall surface as indicated by arrow h and is guided to the side surface of the second bearing 42. Furthermore, the lubricating oil adhering to the oil guide wall 64 flows down along the inner wall surface as indicated by arrow k, is guided along the lubricating oil guide wall 65 to the side surface of the first bearing 41, and is then guided into the differential case 4 through the helical groove 4f.

[0027] As shown in Figure 4, when the vehicle is moving backward, the lubricating oil swept up by the ring gear 2 flows down the oil guide wall 73 as indicated by arrow q and is guided to the side surface of the second bearing 42. Furthermore, the lubricating oil adhering to the oil guide wall 74 is guided by the oil guide 74a and flows down as indicated by arrow v, and is guided to the side surface of the first bearing 41.

[0028] <First space, second space, and third space> As shown in Figure 2, the space within the carrier 5 consists of a first space 51 formed on the rear left side, a second space 52 formed on the rear right side, and a third space 53 formed on the front side. As shown in Figures 2 to 4, the first space 51 is the space in which the first bearing 41, the ring gear 2 (first gear), and a part of the differential case 4 are arranged. The second space 52 is the space in which the remaining part of the differential case 4 and the second bearing 42 are arranged. As shown in Figure 2, the third space 53 is the space that encloses the third bearings 31 and 32. The third space 53 is formed between the pair of third bearings 31 and 32.

[0029] <First cabinet> As shown in Figures 1 and 2, the first housing 6 is a half-body that forms the front side of the carrier 5. The first housing 6 is positioned in front of the second housing 7 and is fixed to the second housing 7 by bolts (not shown). As shown in Figure 3, the first housing 6 has a first partition wall 61, a lubricating oil receiving section 62, oil guide walls 63, 64, a lubricating oil guide wall 65, a transmission mechanism housing section 66, differential case support housing sections 67, 68, and a drive pinion shaft housing section 69.

[0030] <Second cabinet> As shown in Figures 1 and 2, the second housing 7 is a half-body that forms the rear side of the carrier 5. The second housing 7 is positioned opposite the first housing 6. The length of the first housing 6 in the front-rear direction is longer than the length of the second housing 7 in the front-rear direction. The second housing 7 is substantially the same as the first housing 6, as shown in Figure 3, and includes a second partition wall 71, a lubricating oil receiving section 72, oil guide walls 73, 74, a lubricating oil guide wall 75, a transmission mechanism housing section 76, and differential case support housing sections 77, 78. As shown in Figure 3 or Figure 4, the second housing 7 differs from the first housing 6 in that it does not have a drive pinion shaft housing section 69, and the other parts are substantially symmetrical. In the following, the parts of the first enclosure 6 and the second enclosure 7 that have a substantially symmetrical shape will be explained together as appropriate.

[0031] <Bulkhead> As shown in Figure 3 or Figure 4, the carrier 5 has partitions consisting of a first partition wall 61 that protrudes from the inner bottom surface 5c of the first housing 6 and a second partition wall 71 that protrudes from the inner bottom surface 5c of the second housing 7. As shown in Figure 2, the first partition wall 61 and the second partition wall 71 are connected at a joint surface 5a and are arranged in a straight line when viewed from above. The first partition wall 61 and the second partition wall 71 are arranged to divide a first space 51 in which the first bearing 41 and the ring gear 2 (first gear) are located, and a second space 52 in which the second bearing 42 is located.

[0032] As shown in Figures 3 and 4, the first bulkhead 61 and the second bulkhead 71 protrude upward from the internal bottom surface 5c, directed toward the differential case 4 (rotating body). The first bulkhead 61 and the second bulkhead 71 are formed so as to face each other at a position closer to the teeth 2a of the ring gear 2 (first gear) than the axial center position O2 of the opening 4b provided in the differential case 4 (rotating body).

[0033] <Transmission Mechanism Housing Section> The transmission mechanism housings 66 and 76 are housing spaces for the ring gear 2 and the differential case 4. The transmission mechanism housings 66 and 76 consist of roughly semi-cylindrical spaces formed in the central parts of the first housing 6 and the second housing 7. In other words, the housing space for the ring gear 2 and the differential case 4 is formed by aligning the transmission mechanism housing 66, which is half of this housing space, with the transmission mechanism housing 76, which is half of the housing space. The lubricating oil receiving section 62 of the first housing 6 (see Figures 1 and 3) and the lubricating oil receiving section 72 of the second housing 7 (see Figure 4) are formed above the transmission mechanism housings 66 and 76.

[0034] <Lubricating oil receiver> As shown in Figures 3 and 4, the lubricating oil receiving sections 62 and 72 are lubricating oil retention points for temporarily holding lubricating oil that is away from the oil reservoir section 5b. The lubricating oil receiving sections 62 and 72 are formed opposite each other in symmetrical positions that coincide when the first housing 6 and the second housing 7 are assembled. The lubricating oil receiving sections 62 and 72 are formed on the inner circumferential surfaces of the first housing 6 and the second housing 7 in areas that do not come into contact with the ring gear 2 above the rotation axis O1 of the differential case 4, and in areas that partially overlap with the ring gear 2 in the front-rear direction.

[0035] As shown in Figures 1 and 4, the lubricating oil receiving section 62 is located above the drive pinion gear 3 and the drive pinion shaft housing section 69. As shown in Figures 1 and 4, the lubricating oil receiving sections 62 and 72 are located above the differential case 4. The lubricating oil receiving sections 62 and 72 are formed in a position that is continuous laterally and diagonally downward from the oil guide walls 63 and 73 located adjacent to the right side of the ceiling surface 5e.

[0036] On the lower side walls of the recesses of the lubricating oil receiving portions 62 and 72, projections 62a and 72a are provided, forming walls that guide the lubricating oil that has flowed along the oil guide walls 63 and 73 to the side surface of the second bearing 42.

[0037] The protruding pieces 62a and 72a consist of plate-shaped protrusions that are formed to protrude from the lower ends of the oil guide walls 63 and 73 in the direction of the ring gear 2 on the left side.

[0038] The lubricating oil that remains in the lubricating oil receiving sections 62 and 72 passes through the protrusions 62a and 72a, flows along the walls of the differential case support housing sections 68 and 78 toward the side of the second bearing 42, and is guided into the differential case 4 through the helical groove 4f. In this way, the lubricating oil collected in the lubricating oil receiving sections 62 and 72 flows along the protrusions 62a and 72a, through the end of the second bearing 42, and through the helical groove 4f, and is supplied for lubrication of the second bearing 42 and the drive shaft 8. After that, the lubricating oil is guided into the differential case 4, lubricates the meshing and sliding parts of the pinion gear and side gear, and is discharged from the opening 4b of the differential case 4 into the oil reservoir 5b at the bottom of the carrier 5.

[0039] <Lubricating oil guide wall> As shown in Figures 3 and 4, lubricating oil guide walls 65 and 75 are positioned on the left side of the ceiling surface 5e inside the carrier 5, stepped downwards from the adjacent oil guide walls 64 and 74. The lubricating oil scraped up by the ring gear 2 is scattered and adheres to the ceiling surface 5e, and then flows downwards along the lubricating oil guide walls 65 and 75 via the oil guide walls 63 and 73. Subsequently, the lubricating oil is guided to the left end of the first bearing 41.

[0040] Furthermore, near the lubricating oil guide wall 75 of the second housing 7, an oil guide 74a is provided to guide lubricating oil splashed from the ring gear 2 and lubricating oil that falls from the oil guide wall 74 to flow onto the lubricating oil guide wall 75, which is formed in a stepped manner diagonally downward. As a result, the lubricating oil that falls onto the oil guide 74a flows downward along the left-side lubricating oil guide walls 65 and 75 and is guided to the left end of the first bearing 41.

[0041] In this way, the lubricating oil adhering to the ceiling surface 5e flows along the lubricating oil guide walls 65 and 75, through the first bearing 41, through the helical groove 4f, and is supplied for lubrication of the second bearing 42 and the drive shaft 8. Subsequently, the lubricating oil is guided into the differential case 4, lubricates the meshing and sliding parts of the pinion gear and side gear, and is discharged from the opening 4b of the differential case 4 into the oil reservoir 5b at the bottom of the carrier 5.

[0042] <Differential case support housing> As shown in Figures 3 and 4, the differential case support housings 67, 68, 77, and 78 are housing spaces for the first bearing 41 and the second bearing 42. The differential case support housings 67 and 77 consist of a roughly semi-cylindrical space formed from the left side of the transmission mechanism housings 66 and 76 to the left end of the first housing 6 and the second housing 7. The differential case support housings 68 and 78 consist of a roughly semi-cylindrical space formed from the right side of the transmission mechanism housings 66 and 76 to the right end of the first housing 6 and the second housing 7. The differential case support housings 67, 68, 77, and 78 are formed by joining the first housing 6 and the second housing 7.

[0043] <Drive pinion shaft housing> As shown in Figures 1 and 2, the drive pinion shaft housing 69 is a housing space for housing the drive pinion shaft 3b. The drive pinion shaft housing 69 extends forward from the front central part of the transmission mechanism housing 66.

[0044] ≪Operation of the speed reduction device≫ The reduction gear 1 according to the first embodiment of the present invention is basically configured as described above, and its operation and effects will now be explained with reference to Figures 1 to 4.

[0045] As shown in Figure 1, when moving forward, the ring gear 2 rotates clockwise (in the direction of arrow g) when viewed from the right side. The rotating ring gear 2 scoops up the lubricating oil from the oil reservoir 5b. The lubricating oil adhering to the ring gear 2 is ejected along the tangential direction of the ring gear 2, strikes the upper ceiling surface 5e, and is scattered forward and to the left and right along the oil guide walls 63, 64, 73, 74, as shown in Figures 1, 3, or 4. The lubricating oil scattered forward and to the right flows into the lubricating oil receiving section 62, is temporarily stored there, and then flows down from the lubricating oil receiving section 62.

[0046] Then, as shown in Figures 3 and 4, the lubricating oil that flows from the ceiling surface 5e in the left-right direction flows downward (in the direction of arrows h, k, q, v) along the lubricating oil guide walls 65, 75 and the inner walls of the differential case support housings 77, 78, reaching the sides of the first bearing 41 and the second bearing 42, and is guided into the helical groove 4f of the differential case 4. The lubricating oil guided into the helical groove 4f flows within the helical groove 4f in the direction of the side gear 45 (in the direction of arrows i, m, r, x) and is guided into the differential case 4.

[0047] The lubricating oil guided into the differential case 4 lubricates the pinion gear 44 and side gear 45, and is discharged from the opening 4b into the oil reservoir 5b and returned.

[0048] Furthermore, as shown in Figure 1, some of the lubricating oil scraped up by the ring gear 2 flows through the oil passage 33 into the third space 53 (in the direction of arrow c), lubricating the sliding parts of the third bearings 31 and 32, the oil seal 35 in front of the third bearings 31 and 32, and the drive pinion shaft 3b. The lubricating oil in the third space 53 flows from the third space 53 through the oil passage 34 to the oil reservoir 5b on the second space 52 side (in the directions of arrows d and e).

[0049] The lubricating oil that flows into the oil reservoir 5b (direction of arrow f) is prevented from colliding with the rotating ring gear 2 because the first partition wall 61 (see Figures 2-4) and the second partition wall 71 are provided protruding from the internal bottom surface 5c. Therefore, the rib-shaped first partition wall 61 (see Figures 2-4) and the second partition wall 71 can reduce rotational loss of the ring gear 2 and the stirring resistance of the lubricating oil.

[0050] The opening 4b of the differential case 4 is formed extending from the center in the left-right (vehicle width) direction to a position slightly to the right. Below the opening 4b, at the bottom of the differential case 4, a partition wall (first partition wall 61 and second partition wall 71) is formed below the space between the ring gear 2 and the opening 4b. As a result, most of the lubricating oil discharged from the opening 4b into the oil reservoir 5b of the carrier 5 accumulates in the oil reservoir 5b on the second space 52 side, which is to the right of the partition wall (first partition wall 61 and second partition wall 71). When the amount of lubricating oil stored in the oil reservoir 5b on the right side of the partition wall (first partition wall 61 and second partition wall 71) exceeds the height of the partition wall, it flows over the partition wall and into the first space 51 on the left side where the ring gear 2 is located.

[0051] In this way, the lubricating oil that remains in the oil reservoir 5b at the bottom 5d of the carrier is temporarily stored in the area of ​​the oil reservoir 5b on the right side where the ring gear 2 is not located, and then gradually flows into the oil reservoir 5b on the left side. As a result, the oil level of the lubricating oil remaining in the oil reservoir 5b on the left side where the ring gear 2 is located is kept low, thereby keeping the stirring resistance by the ring gear 2 low, while ensuring an appropriate amount of lubricating oil necessary for lubricating bearings and the like.

[0052] Furthermore, the lubricating oil that is scraped up by the ring gear 2, hits the ceiling surface 5e, and then flows towards the lubricating oil guide walls 65 and 75 flows symmetrically with respect to the aforementioned lubricating oil flow, as shown in Figures 3 and 4. In other words, the lubricating oil that is scraped up by the ring gear 2 and flows towards the lubricating oil guide walls 65 and 75 is guided downward along the inner wall of the carrier 5 and flows to the outside of the second bearing 42 and the differential case 4 (in the direction of arrow k). The lubricating oil that reaches the sliding contact area between the drive shaft 8 and the differential case 4 flows through the helical groove 4f in the boss portion 4d of the differential case 4 towards the side gear 45 (in the direction of arrow m) and is guided into the interior of the differential case 4.

[0053] As described above, the reduction gear 1 according to the first embodiment of the present invention, as shown in Figures 1 to 4, comprises a differential case 4 (rotating body) supported at both ends by a first bearing 41 and a second bearing 42, a ring gear 2 (first gear) arranged near the first bearing 41 and rotating integrally with the differential case 4, and a carrier 5 (housing) enclosing the first bearing 41, the second bearing 42, the differential case 4, and the ring gear 2. The carrier 5 protrudes from its internal bottom surface 5c toward the differential case 4 and faces the teeth 2a of the ring gear 2, and has partition walls (first partition wall 61 and second partition wall 71) that divide a first space 51 in which at least a part of the first bearing 41 and the ring gear 2 are arranged, and a second space 52 in which at least a part of the second bearing 42 is arranged.

[0054] In this configuration, the carrier 5 has partition walls (first partition wall 61 and second partition wall 71) protruding from its internal bottom surface 5c along the ring gear 2, dividing the first space 51 and the second space 52. Most of the lubricating oil that reaches the bottom 5d of the carrier is temporarily stored in the oil reservoir 5b on the second space 52 side, and when the oil volume reaches a level that exceeds the partition wall, it flows over the partition wall and gradually into the oil reservoir 5b on the first space 51 side where the ring gear 2 is located. As a result, the lubricating oil remaining in the oil reservoir on the ring gear 2 side can be kept from rising higher than desired while ensuring that the lubricating oil is scraped up by the ring gear 2. As a result, the reduction gear 1 of the present invention can suppress the stirring resistance of the lubricating oil in the oil reservoir 5b by the ring gear 2, thereby preventing a decrease in fuel efficiency and improving fuel efficiency. Furthermore, by changing the height of the partition wall, the present invention makes it possible to control the timing of the lubricating oil flowing from the oil reservoir 5b on the second space 52 side to the oil reservoir 5b on the first space 51 side. Therefore, the lubricating oil stored in the oil reservoir 5b offers a high degree of flexibility in achieving both suppression of the stirring resistance of the ring gear 2 and lubrication performance.

[0055] Furthermore, as shown in Figure 1, the carrier 5 (housing) is composed of a first housing 6 and a second housing 7, which are separated by a joint surface 5a passing through the rotation center of the differential case 4 (rotating body). The partition wall consists of a first partition wall 61 formed in the first housing 6 and a second partition wall 71 formed in the second housing 7, and the first partition wall 61 and the second partition wall 71 are connected by the joint surface 5a.

[0056] With this configuration, the partition wall is composed of a first partition wall 61 and a second partition wall 71. By joining the first housing 6 and the second housing 7, a partition wall consisting of the first partition wall 61 and the second partition wall 71 can be formed. Furthermore, since the partition wall can be molded on both the first housing 6 side and the second housing 7 side, the design freedom of the partition wall shape can be increased, making it possible to form it into a desired shape.

[0057] Furthermore, as shown in Figures 3 and 4, the differential case 4 (rotating body) has a rotation center O1 of the differential case 4 and a hollow spherical shell portion 4a with an opening 4b formed on the outer circumference of the differential case 4, between the ring gear 2 (first gear) and the second bearing 42. The partition walls (first partition wall 61 and second partition wall 71) are formed closer to the ring gear 2 (first gear) than the axial center position O2 of the differential case 4 of the opening 4b.

[0058] With this configuration, the opening 4b allows most of the lubricating oil discharged from the differential case 4 to be stored in the second space 52, thereby suppressing the amount of lubricating oil stored in the first space 51.

[0059] Furthermore, as shown in Figures 1, 2, and 4, the carrier 5 (housing) contains a drive pinion gear 3 (second gear) that meshes with the ring gear 2 (first gear), third bearings 31 and 32 that support the drive pinion gear 3, a third space 53 that encloses the third bearings 31 and 32, and an oil passage 34 that communicates with the third space 53 and the second space 52.

[0060] In this configuration, the carrier 5 has a third space 53 containing the third bearings 31 and 32, and an oil passage 34 communicating with the third space 53 and the second space 52. Therefore, after lubricating the third bearings 31 and 32 supported by the drive pinion gear 3, the lubricating oil is discharged from the oil passage 34 to the bottom of the first housing 6 and stored in the oil reservoir 5b on the second space 52 side. The oil passage 34 is formed to allow the lubricating oil to flow from the third space 53 to the second space 52, so that it cannot flow to the first space 51 side unless it crosses the partition wall from the second space side. Therefore, the partition wall can regulate the amount of lubricating oil stored in the oil reservoir 5b on the first space 51 side, thereby suppressing the stirring resistance of the ring gear 2.

[0061] [Second Embodiment] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of its technical concept. Naturally, the present invention also extends to such modified and altered inventions.

[0062] Figure 5 is a longitudinal cross-sectional view showing a reduction gear 1A according to a second embodiment of the present invention. Figure 6 is a cross-sectional view taken along line VI-VI of Figure 5.

[0063] Furthermore, as shown in Figure 5 or Figure 6, the carrier 5 (housing) described above is composed of a first housing 6 and a second housing 7A, which are divided by a joint surface 5a passing through the rotation center of the differential case 4 (rotating body). Inside the first housing 6, there is a lubricating oil receiving portion 62 formed on the upper part of the third bearings 31 and 32 and on the radial extension line of the ring gear 2 (first gear). Inside the second housing 7A, there may be a third partition wall 73A formed continuously with the second partition wall 71A formed in the second housing 7A and positioned on the upper interior surface of the second housing 7A.

[0064] In this configuration, the carrier 5 of the reduction gear 1A of the first embodiment shown in Figure 5 is composed of a first housing 6 and a second housing 7A. The carrier 5 has a lubricating oil receiving section 62 located inside the upper part of the first housing 6, and a third partition wall 73A located on the upper interior surface of the second housing 7A opposite to the lubricating oil receiving section 62. As a result, the lubricating oil scooped up by the rotating ring gear 2 is guided by the second partition wall 71A and the third partition wall 73A within the first space 51 and the second space 52 shown in Figure 6, and flows along the third partition wall 73A. As shown in Figure 5, the lubricating oil receiving section 62, which stores the lubricating oil, is directed by the third partition wall 73A so that the lubricating oil flows from the third partition wall 73A into the lubricating oil receiving section 62, thus enabling efficient collection of the lubricating oil.

[0065] [Third Embodiment] Figure 7 is a diagram showing a reduction gear 1 according to a third embodiment of the present invention, and is a cross-sectional view of the main part showing the installation state of the flow path 54.

[0066] Furthermore, as shown in Figure 7, at least one of the first partition wall 61 and the second partition wall 71 may have a flow path 54B that communicates with the first space 51 (see Figures 2 to 4) and the second space 52 (see Figures 2 to 4). Figure 7 shows the case where the flow path 54B is formed in the second partition wall 71.

[0067] In this case, as an example of the flow path 54B, the flow path 54B consists of a notched groove that communicates with the first space 51 (see Figures 2 to 4) and the second space 52 (see Figures 2 to 4) from the vicinity of the inner bottom surface 5c of the joint surface 5a of the carrier 5. The flow path 54B is formed by creating a notched groove in at least one of the joint surface 5a of the first partition wall 61 and the joint surface 5a of the second partition wall 71.

[0068] With this configuration, the first partition wall 61 or the second partition wall 71 has a flow path 54B, which allows the lubricating oil accumulating in the second space 52 (see Figures 2 to 4) to gradually flow into the first space 51 (see Figures 2 to 4) through the flow path 54B. Since the flow path 54B is formed by a notched groove, the size of the notched groove can be arbitrarily determined, which increases the degree of freedom in obtaining an oil storage structure that balances the lubricating performance of the lubricating oil with the stirring resistance.

[0069] [Fourth Embodiment] Figure 8 is a diagram showing a reduction gear 1 according to a fourth embodiment of the present invention, and is a cross-sectional view of the main part showing the installation state of valve 55C. Figure 9 is an enlarged cross-sectional view taken along line IX-IX in Figure 8, showing the installation state of valve 55C. Figure 10 is an enlarged cross-sectional view taken along line IX-IX in Figure 8, showing the state when valve 55C is open.

[0070] The flow path 54B in the third embodiment shown in Figure 7 is not limited to simply being used for flowing lubricating oil, but may be modified as appropriate.

[0071] As shown in Figures 8 to 10, the flow path 54B may be equipped with a valve 55C that opens and closes in response to fluctuations in oil temperature.

[0072] In this case, the valve 55C, for example, consists of an on-off valve comprising a valve body 55Ca that opens and closes the flow path 54B, and a valve body support member 55Cb for supporting the valve body 55Ca on a carrier 5 such as a first partition wall 61 or a second partition wall 71. As a method for obtaining a valve that opens and closes in response to fluctuations in oil temperature, the valve body 55ca is preferably formed from a shape memory alloy or a bimetal.

[0073] The valve body 55Ca is, for example, made of a metal plate member that opens and closes the flow path 54B. The valve support member 55Cb consists of a metal plate member that is formed in a clip shape when viewed in cross-section, and is fixed to the base end of the valve body 55Ca by welding or the like. The valve support member 55Cb is attached, for example, to a portion of the first partition wall 61 adjacent to the flow path 54B.

[0074] With this configuration, the flow path 54B is equipped with a valve 55C that opens and closes in conjunction with the temperature of the lubricating oil. This makes it possible to close the valve 55C when the viscosity of the lubricating oil increases in a low-temperature environment. Therefore, by closing the valve 55C when the temperature of the lubricating oil decreases, the amount of lubricating oil that accumulates in and flows into the space on the first bearing 41 side can be reduced, and the stirring resistance of the ring gear 2 can be kept low.

[0075] [Differentiation] For example, the partition wall is formed integrally with the first and second housings 6 and 7, which are made of cast metal, as shown in Figures 3 and 4. However, the partition wall may also be formed as a separate component from steel plate or resin and installed in the housing by bolt fastening or the like. [Explanation of Symbols]

[0076] 1,1A reduction gear 2. Ring gear (first gear) 2a Teeth 3. Drive pinion gear (second gear) 4. Differential case (rotating body) 4a Spherical shell part 4b opening 5. Carrier (Housing) 5a Joint surface 5b Oil reservoir 5c Internal bottom 6. First cabinet 7,7A Second enclosure 31,32 Third bearing 34 Oil road 41 First bearing 42 Second bearing 51 1st space 52 Second space 53 Third space 54B channel 55C valve 61 1st bulkhead (bulkhead) 62 Lubricating oil receiver 71,71A 2nd bulkhead (bulkhead) 73A 3rd bulkhead O1 Rotation center of the differential case (rotation center of the rotating body)

Claims

1. A rotating body supported at both ends by a first bearing and a second bearing, A first gear disposed near the first bearing and rotating integrally with the rotating body, A housing having an oil reservoir portion for storing lubricating oil at the bottom, enclosing the first bearing, the second bearing, the rotating body, and the first gear, The housing is Projecting from the inner bottom surface toward the rotating body, Facing the tooth portion of the first gear, Having a partition wall that partitions a first space in which at least a part of the first bearing and the first gear are disposed and a second space in which at least a part of the second bearing is disposed, The rotating body is Between the first gear and the second bearing, a hollow spherical shell portion having a rotation center of the rotating body and an opening formed in an outer peripheral portion of the rotating body, A gear storage chamber for accommodating a pinion gear and a side gear, Formed on the inner peripheral surface of a cylindrical boss portion onto which the first bearing and the second bearing are externally fitted, and having a spiral groove for guiding lubricating oil flowing down from the inner wall of the housing to the side surfaces of the first bearing and the second bearing into the gear storage chamber, The lubricating oil in the oil reservoir portion scraped up by the first gear Contacts the ceiling surface of the housing, flows down from the inner wall of the housing to the side surfaces of the first bearing and the second bearing, flows into the rotating body from the spiral groove, lubricates the meshing portion and the sliding contact portion of the pinion gear and the side gear, and is discharged from the opening to the oil reservoir portion, The housing is composed of a first housing and a second housing divided by a joint surface passing through the rotation center of the rotating body, The partition wall is A first partition wall formed in the first housing, A second partition wall formed in the second housing, The first partition wall and the second partition wall are connected at the joint surface, At least one of the first partition wall and the second partition wall Has a flow path communicating with the first space and the second space, The flow path consists of a notch groove formed in at least one of the joint surface of the first partition wall and the joint surface of the second partition wall, The flow path is Provided with a valve that opens and closes with changes in oil temperature, The valve is A valve body for opening and closing the flow path, A valve body support member that is fixed to the base end portion of the valve body, is attached so as to sandwich the joint surface of the first partition wall or the second partition wall, and has a substantially U-shaped cross section when viewed in cross section, and consists of an on-off valve, A reduction gear.

2. The partition wall is formed at a position closer to the first gear than the axial center position of the rotating body of the opening. The speed reduction device according to claim 1.

3. Inside the aforementioned enclosure, A second gear that meshes with the first gear, A third bearing supporting the aforementioned second gear, The third space enclosing the aforementioned third bearing, An oil passage communicating with the third space and the second space, It has The reduction gear according to claim 2.

4. The housing consists of a first housing and a second housing, which are divided at a joint surface passing through the rotation center of the rotating body. The first housing has a lubricating oil receiving portion formed on the upper part of the third bearing and on the radial extension line of the first gear, The second housing has a third partition wall which is formed continuously with the second partition wall formed in the second housing and is located on the upper interior surface of the second housing. The speed reduction device according to claim 3.

Images