Vehicle power transmission device

Abstract

To provide a vehicle power transmission device which can inhibit an oil from being jetted from a breather plug even at cryogenic temperature.SOLUTION: When a breather plug 24 is viewed in a direction parallel to a rotation axis C1 of a ring gear 12, a tip at the side housed in an internal space 20 of a case 14 of the breather plug 24 is disposed at the inner periphery side relative to an outer shape of the ring gear 12. Thus, an oil scraped by the ring gear 12 and adhering to an inner wall of the case 14 is inhibited from penetrating from the tip of the breather plug 24 into the breather plug 24. As a result, the structure can inhibit the oil from jetting to an external space through the breather plug 24 while eliminating a breather chamber formed at the case 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a breather device to be attached to a power transmission device for a vehicle. [Background technology]

[0002] Patent Document 1 describes a power transmission device for a vehicle that includes a breather plug attached to a housing and a breather chamber formed within the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-74104 Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle power transmission device described in Patent Document 1, at extremely low temperatures, the highly viscous oil stirred up by the rotation of the gears tends to stick to and remain on the inner wall of the housing. As a result, the amount of oil sticking to the inner wall increases over time, making it more likely for the oil to enter and remain in the breather chamber. As a result, there is a risk that the oil remaining in the breather chamber will blow out from the breather plug.

[0005] The present invention has been made in light of the above circumstances, and its object is to provide a power transmission device for a vehicle that can suppress oil from blowing out from a breather plug at extremely low temperatures. [Means for solving the problem]

[0006] The gist of the present invention is to provide a vehicle that is rotated while running. Ring gear and, a pinion gear that meshes with outer teeth formed on the outer periphery of the ring gear; The aforementioned Ring gear and the pinion gear a case that houses the above-mentioned in an internal space, and a breather plug attached to the case, Ring gear a lubrication structure for lubricating oil stored in the case by a lubricating plug, the lubricating plug being attached to the case by a lubricating valve; Ring gear When viewed in a direction parallel to the rotation axis of the The outer teeth of the ring gear It is characterized in that it is arranged on the inner circumferential side of the [Effects of the Invention]

[0007] According to the present invention, a breather plug is Ring gear When viewed in a direction parallel to the rotation axis of the breather plug, the tip of the side that is housed in the internal space of the case is Ring gear outer teeth Since it is located on the inner side of the Ring gear This prevents oil that has been stirred up by the oil pump and stuck to the inner wall of the case from entering the breather plug from the tip of the breather plug. As a result, it is possible to prevent oil from spraying out into the external space through the breather plug while eliminating the need for a breather chamber in the case. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a transfer to which the present invention is applied. [Figure 2] FIG. 1 is a cross-sectional view of a transfer case having a conventional structure. [Figure 3] FIG. 2 is a diagram showing a portion where oil adheres to the inner wall of the case in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a cross-sectional view of a transfer case 10 to which the present invention is applied. FIG. 1 shows the arrangement of the transfer case 10 when mounted on a vehicle on a flat road. The left side of the paper in FIG. 1 corresponds to the front of the vehicle (vehicle traveling forward) when mounted on the vehicle, and the top of the paper in FIG. 1 corresponds to the vertically upward direction when mounted on the vehicle. The transfer case 10 corresponds to the vehicle power transmission device of the present invention.

[0011] The transfer 10 is a part of a power transmission device for a vehicle that transmits power from a power source such as an engine to drive wheels, and distributes the power of the power source to the front and rear wheels.

[0012] The transfer 10 includes a ring gear 12 that rotates around a rotation axis C1 during running, a case 14 that houses the ring gear 12 in an internal space 20, a pinion gear 16 that meshes with the ring gear 12, and a bearing 18 that rotatably supports the pinion gear 16. The ring gear 12 corresponds to the gear of the present invention.

[0013] Ring gear 12 is Has outer teeth 12a on the outer periphery It consists of bevel gears, The outer teeth 12a The ring gear 12 is meshed with the pinion gear 16. Therefore, when the ring gear 12 rotates, the pinion gear 16 is rotated about the rotation axis C2. The counterclockwise direction indicated by the arrow of the ring gear 12 corresponds to the forward direction of the vehicle.

[0014] The case 14 is a non-rotating member and has an internal space 20 that houses the ring gear 12 and other components. The case 14 rotatably supports the pinion gear 16 via a bearing 18. The case 14 also rotatably supports the ring gear 12 via a bearing (not shown).

[0015] The pinion gear 16 meshes with the ring gear 12 and is supported by a bearing 18 so as to be rotatable about a rotation axis C2. A shaft 22 is fixed integrally to the inner periphery of the pinion gear 16.

[0016] A predetermined amount of oil is sealed within the internal space 20 of the case 14, and the oil is stored in the vertical lower portion of the case 14 when the transfer case 10 is mounted on the vehicle. When mounted on the vehicle, the lower portion of the ring gear 12 is immersed in the oil stored in the lower portion of the case 14. Therefore, when the ring gear 12 rotates while the vehicle is running, the oil stored in the lower portion of the case 14 is scooped up by the ring gear 12 and supplied as lubricating oil to parts requiring lubrication, such as the meshing portion between the ring gear 12 and the pinion gear 16 and the bearing 18. In this way, the transfer case 10 is provided with a lubrication structure that supplies the oil scooped up by the ring gear 12 to parts requiring lubrication.

[0017] A breather plug 24 is also attached to the case 14. The breather plug 24 opens when the pressure in the internal space 20 of the case 14 increases, allowing the air in the internal space 20 to escape to the outside space and suppressing the increase in pressure in the internal space 20.

[0018] An enlarged view of the breather plug 24 is shown in the upper part of Fig. 1. The breather plug 24 is attached to a wall located above the case 14 in the vertical direction when the engine is mounted on the vehicle. The breather plug 24 is also arranged so that its longitudinal direction is aligned with the vertical direction when the engine is mounted on the vehicle.

[0019] The breather plug 24 includes a breather body 26 , a cap 28 , a disk member 30 , and a spring 32 .

[0020] The breather body 26 is a substantially cylindrical member having a predetermined dimension in the longitudinal direction, penetrates the case 14, and is attached with its longitudinal direction parallel or substantially parallel to the vertical direction when the breather body 26 is mounted on the vehicle. The breather body 26 is fixed by screws or the like to a through-hole formed in the case 14. The breather body 26 is formed with a flange 34 that protrudes perpendicular to the longitudinal direction, and is positioned by abutting the flange 34 against the case 14. A communication hole 36 is formed at the tip of the breather body 26 on the side that is housed in the internal space 20 of the case 14, allowing air to enter the interior. A diameter-enlarged portion 40 that extends radially outward is formed at the tip of the breather body 26 that is located on the external space side relative to the case 14.

[0021] The cap 28 is formed in a cylindrical shape with a bottom, and is provided so as to cover the portion of the breather body 26 that protrudes from the case 14. A claw portion 38 that protrudes radially inward is formed at the end of the opening side of the cap 28. The claw portion 38 is provided so as to be able to come into contact with an expanded diameter portion 40 of the breather body 26, and the contact of the claw portion 38 with the expanded diameter portion 40 prevents the cap 28 from falling off the breather body 26.

[0022] The disk member 30 is housed in the cap 28 and abuts against the expanded diameter portion 40 of the breather body 26, thereby closing the opening formed in the breather body 26. The spring 32 is housed inside the cap 28 and urges the disk member 30 toward the expanded diameter portion 40 of the breather body 26. As a result, in the normal state, the opening of the breather body 26 is closed by the disk member 30, preventing air in the internal space 20 of the case 14 from being released into the external space of the case 14 through the breather plug 24.

[0023] On the other hand, when the pressure in the internal space 20 of the case 14 increases, the disk member 30 moves away from the expanded diameter portion 40 against the biasing force of the spring 32, forming a gap between the disk member 30 and the expanded diameter portion 40. At this time, the breather plug 24 opens, and air is released to the outside from the gap formed between the disk member 30 and the expanded diameter portion 40, thereby suppressing the increase in pressure in the internal space 20.

[0024] Next, the structure of a conventional transfer case 100 and the problems associated with the transfer case 100 will be described. Figure 2 is a cross-sectional view of a conventional transfer case 100. In the conventional structure, a breather chamber 104 extending in the fore-and-aft direction of the vehicle is formed in a case 102. The breather chamber 104 is also capable of communicating with the space outside the case 102 via a breather plug 106.

[0025] Here, at extremely low temperatures, the oil that is scooped up toward the outer periphery by the ring gear 108 tends to stick to the inner wall of the case 102. At this time, the oil enters the breather chamber 104 and tends to accumulate in the shaded area of ​​the breather chamber 104. As a result, if the amount of oil that accumulates in the breather chamber 104 increases over time, there is a risk that when the breather plug 106 opens, the oil in the breather chamber 104 will blow out together with air from the breather plug 106 into the space outside the case 102, as shown by the arrows.

[0026] 1, when the breather plug 24 is viewed in a direction parallel to the rotational axis C1 of the ring gear 12, the tip of the breather plug 24 that is housed in the internal space 20 is located more inward than the outer shape of the ring gear 12. In other words, when the rotational axis C1 is used as the reference, the portion of the breather body 26 where the communication hole 36 is formed (hereinafter referred to as the tip of the breather plug 24) is located radially inward than the ring gear 12. To achieve this, the portion of the breather body 26 that is housed in the internal space of the case 14 is extended longitudinally more than a breather plug of a conventional structure (breather plug 106 in FIG. 2).

[0027] As described above, the tip of the breather plug 24 is extended to a position more inward than the ring gear 12 with respect to the rotation axis C1, so that oil that has been scooped up by the ring gear 12 and stuck to the inner wall of the case 14 is prevented from entering the interior from the tip of the breather plug 24.

[0028] FIG. 3 is a diagram showing the areas where oil scooped up by the ring gear 12 in FIG. 1 splashes. When the ring gear 12 rotates counterclockwise as indicated by the arrow, oil stored in the case 14 is scooped up and thrown outward by centrifugal force. As a result, oil splashes in the shaded areas in FIG. 3. Furthermore, at extremely low temperatures, oil adheres to and sticks to the inner wall of the case 14 corresponding to these areas. However, as shown in FIG. 3, the tip of the breather plug 24 (i.e., the area where the communication hole 36 is formed) is located closer to the interior of the case 14 than the shaded area. This prevents oil that has stuck to the inner wall of the case 14 from entering the interior through the tip of the breather plug 24 (the communication hole 36). As a result, even at extremely low temperatures, oil that has stuck to the inner wall of the case 14 is prevented from passing through the breather plug 24 and leaking into the space outside the case 14.

[0029] As described above, according to this embodiment, when the breather plug 24 is viewed in a direction parallel to the rotational axis C1 of the ring gear 12, the tip of the breather plug 24 on the side that is housed in the internal space 20 of the case 14 is located more inward than the outer shape of the ring gear 12, which prevents oil that has been scooped up by the ring gear 12 and stuck to the inner wall of the case 14 from entering the breather plug 24 from the tip of the breather plug 24. As a result, it is possible to prevent oil from passing through the breather plug 24 and spraying out into the external space while eliminating a breather chamber formed in the case 14.

[0030] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0031] For example, in the above-described embodiment, the breather plug 24 is attached to the case 14 of the transfer 10 that constitutes a vehicle power transmission device, but the present invention is not necessarily limited to the transfer 10. For example, the present invention can be applied to any device that has a lubrication structure in which oil stored in the case is scooped up by the gears, such as a differential gear.

[0032] In the above-described embodiment, the oil stored in the case 14 is scooped up by the ring gear 12, which is a bevel gear. However, the gear that scoops up the oil is not limited to a bevel gear. For example, the present invention can be applied to any gear that scoops up the oil, such as a helical gear.

[0033] It should be noted 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. [Explanation of symbols]

[0034] 10: Transfer (power transmission device for vehicle) 12: Ring gear (gear) 14: Case 20: Internal space 24: Breather plug C1: Rotation axis (rotation axis of gear)

Claims

[Claim 1] A power transmission device for a vehicle includes a ring gear that is rotated while the vehicle is running, a pinion gear that meshes with outer teeth formed on the outer periphery of the ring gear, a case that houses the ring gear and the pinion gear in an internal space, and a breather plug attached to the case, the power transmission device having a lubrication structure in which oil stored in the case is scooped up by the ring gear, When the breather plug is viewed in a direction parallel to the rotation axis of the ring gear, a tip of the breather plug that is housed in the internal space is disposed on the inner peripheral side of the outer peripheral teeth of the ring gear. A power transmission device for a vehicle.

Images