Vehicle differential system breather structure

Abstract

To provide a breather structure for a vehicular differential device capable of appropriately suppressing leakage of oil without deteriorating a function of a breather.SOLUTION: In a breather structure Br for a vehicular differential device 1 that includes a differential gear mechanism 3 incorporated into a differential case 7, a housing 4 accommodating and holding the differential gear mechanism 3 and a breather 11 and performs scooping lubrication by using oil 10 in the housing 4, the breather 11 includes: a breather chamber 12 opened in a space within the housing 4; a breather port 13; a deflector plate 14 mounted to an opening part 12a of the breather chamber 12 with bolts 16, 17 to shield the opening part 12a; and a vent hole 18 for causing air to flow between inside of the housing 4 and the breather chamber 12. The vent hole 18 is formed in a circumferential direction CD of a ring gear 6 passing through a mounting position of the bolt 16 in the deflector plate 14.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a breather structure for adjusting the pressure in a housing of a vehicle differential device that distributes and transmits power to left and right drive shafts and enables differential rotation of those drive shafts.

Background Art

[0002] A differential device mounted on a vehicle is described in Patent Document 1. The vehicle differential device described in this Patent Document 1 includes, inside a housing, a final reduction gear mechanism composed of a drive pinion and a ring gear, a differential gear mechanism composed of a side gear and a pinion, etc., and a breather. The differential gear mechanism is disposed inside a differential gear case (differential case) having a ring gear assembled to its outer peripheral portion. The inside of the housing is kept liquid-tight and filled with oil for lubrication and cooling. The breather is composed of a space (breather chamber) formed above the differential case inside the housing, and a deflector plate that shields the opening portion of the breather chamber. The deflector plate is attached to the breather chamber (inner wall portion of the housing) by a plurality of screws (bolts). Note that the deflector plate in the differential device described in this Patent Document 1 is formed so as to have a magnetic force, prevent oil from entering the breather chamber, and adsorb iron powder and foreign magnetic substances mixed in the oil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described in Patent Document 1 above, a breather is generally provided in a differential device for a vehicle. The breather is configured to release air from inside the housing to the outside, thereby suppressing pressure changes inside the housing due to temperature changes, etc. The breather in the differential device described in Patent Document 1 above has a notch that allows air to flow between the inside of the housing and the deflector plate and breather chamber, and a breather port that penetrates from the inner wall surface of the breather chamber to the outside. Therefore, when the air inside the housing expands or contracts, air is released or drawn in through the notch, breather chamber, and breather port as described above. This function of the breather mitigates pressure changes inside the housing of the differential device. On the other hand, when the vehicle moves forward or backward, the gear mechanism of the differential device (for example, the ring gear in the differential gear mechanism described in Patent Document 1) rotates and scrapes up oil inside the housing, and the scraped-up, foamy oil or accumulated oil enters the breather chamber. Furthermore, if the breather chamber fills with oil, in conventional breather designs, the accumulated oil can block the ventilation holes in the breather chamber, impairing the breather's function of circulating air and mitigating pressure changes within the housing. In addition, there is a risk that the oil, having nowhere else to go inside the breather chamber, may leak out through the ventilation holes.

[0005] This invention was conceived in response to the technical problems described above, and aims to provide a breather structure for a vehicle differential that can appropriately suppress oil leakage without degrading the breather's function. [Means for solving the problem]

[0006] To achieve the above objective, this invention provides a breather structure for a vehicle differential device, comprising: a final reduction mechanism having a ring gear to which torque is transmitted from the vehicle's power source; a differential gear mechanism incorporated in a differential case (differential gear case) on which the ring gear is attached to the outer circumference; a housing that accommodates and holds the final reduction mechanism and the differential gear mechanism; and a breather that adjusts the pressure inside the housing, wherein the breather structure performs splash-type lubrication with oil sealed inside the housing. In the housing, the inner wall portion on the outer circumference side of the upper part of the ring gear is recessed relative to the inside of the housing. A breather chamber, a breather port for circulating air between the breather chamber and the outside of the housing, and a bolt or screw attached to the opening of the breather chamber. Before A deflector plate that shields the opening, and a ventilation hole that allows air to circulate between the inside of the housing and the breather chamber. The device comprises a hood that covers the inside of the housing of the ventilation hole and is positioned adjacent to the bolt in the direction of the flow of the oil scraped up by the ring gear, protruding from the deflector plate to the inside of the housing and molded integrally with the deflector plate, an opening formed in the hood so as to open opposite the head of the bolt, and a notch formed in the deflector plate between the bolt and the hood by cutting out the deflector plate by the thickness of the plate. It is characterized by the following:

[0008] In the present invention, the height of the opening of the hood is such that the front protrudes from the surface of the deflector plate. The configuration may be smaller than the height dimension of the head. Furthermore, in the present invention, the opening of the hood may face upstream in the direction in which the oil, which is scraped up by the ring gear when the vehicle is moving in reverse, flows, and may face the head of the bolt. [Effects of the Invention]

[0009] The breather structure for a vehicle differential of this invention relates to a breather for adjusting the pressure inside the housing of a vehicle differential. The breather consists of a breather chamber (space) formed in the inner wall of the housing, a deflector plate that closes the opening of the breather chamber, a breather port that connects the breather chamber to the outside of the housing, and a ventilation hole that connects the inside of the housing to the breather chamber. The deflector plate is , It is attached by bolts to the opening of the leeser chamber, i.e., to the inner wall portion of the housing. The deflector plate has ventilation holes formed in it that allow air to circulate through the deflector plate. A hood that covers the inside of the hole housing is provided protruding from the deflector plate, and this hood is , the circumference of the deflector plate It is positioned adjacent to the bolt in the direction in which the oil, scraped up by the ring gear, flows. Furthermore, in order to easily form the hood and opening, a notch is provided in the portion between the hood and the bolt, formed by cutting out the deflector plate by the thickness of the plate.Furthermore, in the breather structure of the vehicle differential device of this invention, when the differential gear mechanism and ring gear rotate and scoop up the oil inside the housing, the oil flows in the circumferential direction of the ring gear. In that case, on the surface of the deflector plate, the heads of the bolts This would block the opening of the hood from the flow of oil, and as a result, This makes it more difficult for oil to enter the air pores. As a result, it prevents oil from entering and filling the breather chamber, and suppresses oil leakage from the breather. Furthermore, it ensures the function of the breather, which is to circulate air between the inside and outside of the housing and mitigate pressure changes inside the housing.

[0010] Furthermore, in the breather structure of the vehicle differential device of this invention The height of the bolt heads facing the hood is greater than the height of the hood opening. The bolt head is formed along the circumferential direction, ensuring that the flow of oil in the circumferential direction is not obstructed. To the opening of the hood This effectively prevents oil from seeping in.

[0011] Furthermore, in the breather structure of the vehicle differential device of this invention The opening in the hood faces upstream in the direction of oil flow when the vehicle is moving in reverse. Therefore, when the vehicle is moving forward, which is more frequent, the oil flows from the opposite side of the hood from the opening, effectively preventing or suppressing oil from entering the breather chamber. Also, when the vehicle is moving in reverse, which is less frequent, the oil flows towards the opening in the hood, but since the opening is shielded by the bolt head, effectively preventing or suppressing oil from entering the breather chamber.

[0012] Therefore, according to the breather structure of the vehicle differential device of this invention, oil leakage from the breather can be properly suppressed without degrading the breather's function of circulating air between the inside and outside of the housing and mitigating pressure changes inside the housing. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a cross-sectional view showing an example of a vehicle differential device to which the breather structure of this invention is applied. [Figure 2] Figure 2 is a diagram illustrating the configuration of the breather structure of this invention, and is a front view showing the inside of the housing of a vehicle differential device in perspective. [Figure 3]FIG. 3 is a drawing for explaining the function of the breather structure of the present invention, and is a schematic diagram showing the cross-sectional shape of the deflector plate and the ventilation holes, as well as the flow of oil and air in the housing. [Figure 4] FIG. 4 is a drawing for explaining another configuration example (an example in which a plurality of ventilation holes are formed in the deflector plate) of the breather structure of the present invention. (a) of FIG. 4 is a front view showing a configuration in which two ventilation holes are provided in the vicinity of the bolts at both ends for fixing the deflector plate, and (b) of FIG. 4 is a front view showing a configuration in which a ventilation hole close to the bolt for fixing the deflector plate and other ventilation holes at positions along the circumferential direction (of the ring gear) of the deflector plate are provided. [Figure 5] FIG. 5 is a drawing for explaining the specific configuration of the breather structure of the present invention, and is a front view showing an example in which a notch is provided in the deflector plate in order to facilitate the formation of the ventilation holes. [Figure 6] FIG. 6 is a drawing for explaining the specific configuration of the breather structure of the present invention, and is a front view showing an example in which the deflector plate is composed of members of different materials in order to facilitate the formation of the ventilation holes. [Figure 7] FIG. 7 is a drawing for explaining the specific configuration of the breather structure of the present invention, and is a front view showing an example in which the deflector plate is composed of members of different materials in order to facilitate the formation of the ventilation holes. (a) of FIG. 7 is a front view showing an example in which a resin member having ventilation holes is cast around a metal main body member to form the deflector plate, and (b) of FIG. 7 is a front view showing another example in which a resin member having ventilation holes is cast around a metal main body member to form the deflector plate.

MODE FOR CARRYING OUT THE INVENTION

[0014] Embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are merely examples when the present invention is embodied, and do not limit the present invention.

[0015] Figure 1 shows an example of a vehicle differential device 1 to which the breather structure Br in an embodiment of the present invention is applied. The differential device 1 shown in Figure 1 is a so-called "front differential device" and is installed for the front wheels (not shown) of a vehicle (not shown). The differential device 1 includes a final reduction gear mechanism 2, a differential gear mechanism 3, and a housing 4, and distributes and transmits torque while allowing differential rotation of the left and right drive shafts (not shown) of the vehicle. Note that the breather structure Br in the embodiment of the present invention is not limited to the above-mentioned "front differential device" and can also be applied to a "rear differential device" installed for the rear wheels (not shown) of the vehicle.

[0016] The final reduction gear mechanism 2 is a conventionally general "power transmission device" for a vehicle and is a "reduction gear mechanism" composed of a drive pinion 5 and a ring gear 6. Torque is transmitted to the final reduction gear mechanism 2 from a driving force source (not shown) such as an engine, a motor, or a hybrid drive unit.

[0017] The differential gear mechanism 3 is a conventionally general "differential device" for a vehicle and is composed of a differential case (that is, a differential gear case) 7 to which the above ring gear 6 is attached to the outer peripheral portion, and a side gear 8 and a differential pinion 9 incorporated inside the differential case 7. Therefore, the torque of the driving force source is transmitted to the differential gear mechanism 3 from the above final reduction gear mechanism 2 via the ring gear 6.

[0018] The housing 4 houses and holds the final reduction mechanism 2 and the differential gear mechanism 3 as described above. The inside of the housing 4 is kept liquid-tight and is filled with lubricating and cooling oil 10, as shown in Figure 2 below. The oil 10 is agitated and churned up by the ring gear 6 when the final reduction mechanism 2 and the differential gear mechanism 3 rotate within the housing 4. In other words, the differential device 1 is configured to perform splash-type lubrication (or oil bath type lubrication, or churning lubrication) using the oil 10 sealed inside the housing 4.

[0019] A breather 11 is formed inside the housing 4. The breather 11 circulates air between the inside and outside of the housing 4, adjusting the pressure (air pressure) inside the housing 4. In the breather structure Br of this embodiment of the invention, the breather 11 consists of a breather chamber 12, a breather port 13, a deflector plate 14, and a ventilation hole 18 as shown in Figure 2, which will be described later.

[0020] The breather chamber 12 is a space formed in the inner wall portion of the housing 4, recessed inward from the inner wall surface, and opens towards the space inside the housing 4. Furthermore, as shown in Figure 2, the breather chamber 12 is formed in a shape that extends in an arc along the circumferential direction CD of the ring gear 6 in the longitudinal direction (left-right direction in Figure 2).

[0021] The breather port 13 is a vent that connects the breather chamber 12 to the outside of the housing 4, allowing air to circulate between the breather chamber 12 and the outside of the housing 4. In the example shown in Figure 1, the breather port 13 is formed in the upper part of the breather chamber 12 and housing 4 (upper side in Figure 1), above the outer circumference of the ring gear 6 inside the housing 4. A breather plug 15 is also attached to the opening at the upper end of the breather port 13 (not shown).

[0022] The deflector plate 14 is attached to the opening 12a of the breather chamber 12 to shield the opening 12a. As shown in Figure 2, the deflector plate 14 is formed from a plate-shaped member with a shape corresponding to the opening 12a, that is, a shape in which the longitudinal direction (left-right direction in Figure 2) extends in an arc along the circumferential direction CD of the ring gear 6. The deflector plate 14 is attached to the breather chamber 12, that is, the inner wall portion of the housing 4, at both ends in the longitudinal direction by bolts 16 and 17, respectively.

[0023] In the breather structure Br of this embodiment of the invention, at least one ventilation hole 18 is formed in the deflector plate 14 as described above. The ventilation hole 18 allows air to circulate between the inside of the housing 4 (the space inside the housing 4) and the breather chamber 12. In the example shown in Figure 2, one ventilation hole 18 is formed on the side of one of the two bolts 16, 17 that fix the deflector plate 14 (the right side in Figure 2). The ventilation hole 18 is formed at a predetermined position on an arc-shaped line along the circumferential direction CD passing through the mounting positions of the bolts 16, 17 on the deflector plate 14, penetrating the deflector plate 14.

[0024] Furthermore, the ventilation holes 18 open in the circumferential direction CD on the deflector plate 14, facing the heads 16a of the bolts 16. Specifically, as shown in Figure 3, the ventilation holes 18 consist of a through hole 18a and a hood 18b.

[0025] The through-hole 18a is a hole or space formed through the thickness direction (up and down direction in Figure 3) of the deflector plate 14, and allows air to flow in the thickness direction of the deflector plate 14.

[0026] The hood 18b is formed on the deflector plate 14 such that one end covers the through hole 18a, or it is attached to the deflector plate 14. The other end of the hood 18b is an opening 18c that opens opposite the head 16a of the bolt 16. Thus, the hood 18b functions similarly to a 90° “bend pipe” or “elbow” in piping, for example, by changing the direction of airflow through the vent hole 18 by 90° from a direction perpendicular to the deflector plate 14 to a direction parallel to the deflector plate 14.

[0027] In this way, by providing a through hole 18a and a hood 18b to form the ventilation hole 18, the opening 18c of the ventilation hole 18 faces the head 16a of the bolt 16 in the circumferential direction CD on the deflector plate 14. Therefore, as shown in Figure 3, the head 16a of the bolt 16 obstructs the flow of oil 10 in the circumferential direction CD within the housing 4, thereby effectively suppressing the ingress of oil 10 into the ventilation hole 18 formed along the circumferential direction CD. In the example shown in Figure 3, the head 16a of the bolt 16 acts as a resistance or barrier to the flow of oil 10 within the housing 4 when the vehicle is moving in reverse, suppressing the ingress of oil 10 into the ventilation hole 18. When the vehicle is moving forward, the hood 18b covering the through hole 18a suppresses the ingress of oil 10 into the ventilation hole 18.

[0028] Furthermore, as shown in Figure 3, the ventilation holes 18 are formed such that the opening height h1 of the opening 18c is lower than the height h2 of the bolt heads 16a protruding from the surface of the deflector plate 14. The opening height h1 is the dimension in the vertical direction (up and down direction in Figure 3) of the opening 18c, and is, for example, the diameter of the opening 18c, or a dimension corresponding to the diameter of the opening 18c. By forming the ventilation holes 18 in this way, as shown in Figure 3, the bolt heads 16a reliably obstruct the flow of oil 10 in the circumferential direction CD within the housing 4. Therefore, the intrusion of oil 10 into the ventilation holes 18 formed along the circumferential direction CD can be effectively suppressed.

[0029] In the breather structure Br of this embodiment of the invention, a plurality of "ventilation holes" may be provided in the deflector plate 14, as shown in Figure 4. In the example shown in Figure 4(a), along with the ventilation holes 18 described above, a ventilation hole 19 is formed on the side of the other bolt 17 (left side in Figure 4) of the two bolts 16 and 17 that fix the deflector plate 14. The ventilation hole 19, like the ventilation hole 18, consists of a through hole (not shown) and a hood (not shown) having an opening 19a. The ventilation hole 19 is formed so that the opening 19a faces the bolt 17.

[0030] Furthermore, in the example shown in Figure 4(b), along with the ventilation holes 18 described above, ventilation holes 20 are formed at predetermined positions on an arc-shaped line along the circumferential direction CD passing through the mounting positions of the bolts 16 and 17 on the deflector plate 14. The ventilation holes 20, like the ventilation holes 18 and 19, consist of a through hole (not shown) and a hood (not shown) having an opening 20a. In this case, the ventilation holes 20 are formed such that the opening 20a opens in a direction substantially perpendicular to the circumferential direction CD.

[0031] In the example shown in Figure 5, a notch 21 is provided in the deflector plate 14. The notch 21 is formed by cutting out the thickness of the deflector plate 14 from the side surface 14a toward the central part of the deflector plate, continuous with the opening 18c of the ventilation hole 18. By providing such a notch 21, for example, when integrally molding the deflector plate 14 and the hood 18b and opening 18c of the ventilation hole 18 by press working (bulb forming), the molding process can be facilitated and the processability can be improved.

[0032] The "deflector plates" shown in Figures 6 and 7 are formed by combining multiple members made of different materials. The deflector plate 22 shown in Figure 6 is made up of three members: a base portion 22a, a first end portion 22b, and a second end portion 22c. The base portion 22a is formed, for example, by injection molding of plastic, and has a hood 23a and an opening 23b that constitute the ventilation hole 23. The first end portion 22b and the second end portion 22c are made of metal plates such as aluminum alloy or stainless steel, and have bolt holes 22d and 22e for bolt fastening, respectively. Furthermore, the first end portion 22b has a through hole 23c that constitutes the ventilation hole 23. The deflector plate 22 is formed by joining the first end portion 22b and the second end portion 22c to the base portion 22a, for example, by adhesive or welding.

[0033] The deflector plate 24 shown in Figure 7(a) is formed from two components: a ventilation hole portion 24a and a base portion 24b. The ventilation hole portion 24a is formed, for example, by injection molding of plastic, and has a hood 25a, an opening 25b, and a through hole (not shown) that constitute the ventilation hole 25. In addition, cast-in portions 24c and 24d, which are shaped as shown by dashed lines in Figure 7(a), are integrally formed in the ventilation hole portion 24a. The base portion 24b is formed, for example, by aluminum alloy casting or die casting. The deflector plate 24 is formed by integrally molding the ventilation hole portion 24a into the base portion 24b.

[0034] The deflector plate 26 shown in Figure 7(b) is formed from two components: a ventilation hole portion 26a and a base portion 26b. The ventilation hole portion 26a is formed, for example, by injection molding of plastic, and has a hood 27a, an opening 27b, and a through hole (not shown) that constitute the ventilation hole 27. The ventilation hole portion 26a is also provided with casting allowances 26c and 26d, which are shaped as shown by dashed lines in Figure 7(b). The base portion 26b is formed, for example, by aluminum alloy casting or die casting. The deflector plate 26 is formed by integrally molding the ventilation hole portion 26a into the base portion 26b.

[0035] As described above, in the breather structure Br of this embodiment of the invention, ventilation holes 18, 23, 25, 27 are formed in the deflector plates 14, 22, 24, 26, allowing air to circulate through the deflector plates 14, 22, 24, 26. The ventilation holes 18, 23, 25, 27 are formed along the circumferential direction CD of the deflector plates 14, 22, 24, 26, at positions aligned with the mounting positions of the bolts 16 (17). In the breather structure Br of this embodiment of the invention, when the differential gear mechanism 3 and the ring gear 6 rotate and stir up the oil 10 in the housing 4, the oil 10 flows in the circumferential direction CD of the ring gear 6. In that case, the heads of the bolts 16 (17) on the surfaces of the deflector plates 14, 22, 24, and 26 will obstruct the circumferential flow of the oil 10, making it difficult for the oil 10 to enter the ventilation holes 18, 23, 25, and 27 formed on the circumferential CD. Therefore, it is possible to prevent the oil 10 from entering and filling the breather chamber 12, and to suppress the leakage of oil 10 from the breather 11. Furthermore, the function of the breather 11, that is, the function of circulating air between the inside and outside of the housing 4 and mitigating pressure changes inside the housing 4, can be properly ensured.

[0036] Therefore, according to the breather structure Br in this embodiment of the invention, the leakage of oil 10 can be properly suppressed without degrading the function of the breather 11. [Explanation of Symbols]

[0037] 1. Vehicle differential device 2 Final reduction mechanism 3. Differential gear mechanism 4 Housing 5 Drive pinion 6 Ring gear 7. Differential case (differential gear case) 8 side gears 9 Differential pinion 10 Oil 11 Breezer 12. Breather Room 12a Opening (of the breather chamber) 13 Breathaport 14 Deflector Plates 14a Side (of the deflector plate) 15 Breather Plug 16 volts 16a (Bolt) Head 17 volts 18 ventilation holes 18a Through-hole (for ventilation) 18b (Ventilated) Hood 18c (Ventilation hole) opening 19 ventilation holes 19a (Ventilation hole) opening 20 ventilation holes 20a (Ventilation hole) opening 21 Notches 22 Deflector boards 22a Base part (of the divided deflector plate) 22b First end (of the split-structure deflector plate) 22c (Second end of the split-structure deflector plate) 22d Bolt hole (formed at the first end) 22e (Bolt hole formed at the second end) 23 ventilation holes 23a (Ventilated) Hood 23b (Ventilation hole) opening 23c (Ventilation hole) Through hole 24 Deflector Plates 24a Ventilation holes (of the split-structure deflector plate) 24b Base part (of a split-structure deflector plate) 24c (cast-in section provided in the ventilation hole) 24d (cast-in portion provided in the ventilation hole) 25 ventilation holes 25a (Ventilated) Hood 25b (Ventilation hole) opening 26 Deflector Plates 26a Ventilation holes (of the split-structure deflector plate) 26b Base part (of the divided deflector plate) 26c (cast-in allowance provided in the ventilation hole) 26d (cast-in allowance provided in the ventilation hole) 27 ventilation holes 27a (Ventilated) Hood 27b (Ventilation hole) opening Br breather structure Circumferential direction of CD ring gear

Claims

1. A breather structure for a vehicle differential device comprising: a final reduction mechanism having a ring gear to which torque is transmitted from the vehicle's power source; a differential gear mechanism incorporated in a differential case on which the ring gear is attached to the outer circumference; a housing that accommodates and holds the final reduction mechanism and the differential gear mechanism; and a breather that adjusts the pressure inside the housing, wherein lubrication is performed by splashing with oil sealed inside the housing, A breather chamber is formed in the inner wall portion on the outer circumference side of the upper part of the ring gear within the housing, recessed relative to the interior of the housing. A breather port for circulating air between the breather chamber and the outside of the housing, A deflector plate is bolted to the opening of the breather chamber to shield the opening, A ventilation hole for circulating air between the inside of the housing and the breather chamber, A hood, which is molded integrally with the deflector plate and protrudes from the deflector plate toward the inside of the housing, is positioned adjacent to the bolt in the direction of the flow of the oil scraped up by the ring gear, covering the portion of the ventilation hole that opens toward the inside of the housing, The hood has an opening formed so as to open opposite the head of the bolt, In the deflector plate, between the bolt and the hood, there is a notch formed by cutting out the deflector plate by the thickness of the plate. It is equipped with A breather structure for a vehicle differential, characterized by the following features.

2. A breather structure for a vehicle differential according to claim 1, The height of the opening in the hood is lower than the height of the head that protrudes from the surface of the deflector plate. A breather structure for a vehicle differential, characterized by the following features.

3. A breather structure for a vehicle differential according to claim 1 or 2, The opening in the hood faces upstream in the direction in which the oil, which is scraped up by the ring gear when the vehicle is moving in reverse, flows, and is opposite to the head of the bolt. A breather structure for a vehicle differential, characterized by the following features.

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