KR-20260063260-A - Lubrication structure of clutch for limited slip differential

KR20260063260AKR 20260063260 AKR20260063260 AKR 20260063260AKR-20260063260-A

Abstract

A lubrication structure for a clutch for a limited-slip differential is disclosed. A lubrication structure for a clutch for a limited-slip differential according to one embodiment of the present invention forms a plurality of branch holes branching from a main oil passage to supply lubricating oil to a bearing mounting portion of a reduction gear case, forms an oil groove on the inner circumference of a differential cover where a drive shaft is assembled, and forms a plurality of oil holes connected by penetrating radially on the hub of a side gear and the clutch hub, thereby ensuring smooth supply of lubricating oil to the inner diameter side of the clutch for limiting the differential of the differential, so as to ensure the performance, durability, and heat resistance of the clutch.

Inventors

이아람
김진호
천세환

Assignees

현대자동차주식회사
기아 주식회사

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (12)

A side gear configured inside the differential case of the differential and spline-coupled to a drive shaft on one side; A clutch unit comprising a friction material disposed between the clutch hub and the clutch drum, which is spline-coupled to the outer circumference of the hub of the one-sided side gear through a clutch hub and spline-coupled to one side of the differential case through a clutch drum; A differential cover fixed to one side of the clutch drum and covering one side of the clutch unit; and A limited differential device comprising the above differential, the above clutch unit, a piston unit that controls the operation of the above clutch unit, and a reduction gear case that encloses an internal reduction gear, A plurality of branch holes formed by branching axially from the main oil passage to supply lubricating oil to the bearing mounting portion of the above-mentioned reduction gear case; An oil groove formed on the inner circumference of a differential cover to which the above-mentioned one-sided drive shaft is assembled; and A plurality of oil holes penetrating radially through the above-mentioned one-sided side gear and the above-mentioned clutch hub; A lubrication structure for a clutch for a limited-slip differential, characterized by forming a lubrication oil supply path to supply lubrication oil supplied from the main oil path to the inner diameter side of the friction material on the clutch unit.
In paragraph 1, The above oil groove is A lubrication structure for a clutch for a limited-slip differential, comprising two spiral grooves formed in opposite directions along the inner circumferential surface of the differential cover facing the drive shaft.
In paragraph 1, The above plurality of oil holes A plurality of first oil holes formed by penetrating radially into the hub of the above-mentioned one-sided side gear; A plurality of second oil holes that penetrate radially through the inner diameter portion of the clutch hub and are connected to the first oil hole; and A plurality of third oil holes penetrating radially through the outer diameter of the above clutch hub; Lubrication structure of a clutch for a limited-slip differential including
In paragraph 3, The above first oil hole is A lubrication structure for a clutch for a limited-slip differential, wherein an inlet is formed in a missing portion on the inner circumference of the hub of the above-mentioned side gear where spline teeth are not formed.
In paragraph 3, The above first oil hole is A lubrication structure for a clutch for a limited-slip differential, wherein the discharge port is positioned to face the inlet port of the second oil hole, and the second oil hole is positioned such that the discharge port faces the space between the inner diameter and outer diameter portions of the clutch hub.
In paragraph 3, The above second oil hole is A lubrication structure for a clutch for a limited-slip differential, wherein an inlet is formed as a groove along the circumferential direction on one side of the inner surface of the clutch hub and is formed on an oil pocket that collects a portion of the oil supplied from the first oil hole.
In paragraph 3, The above first and second oil holes are A lubrication structure for a clutch for a limited-slip differential formed at a constant angle with respect to the radial direction.
In paragraph 3, The above third oil hole is A lubrication structure for a clutch for a differential limiter formed to face the inner diameter side of the friction material.
In paragraph 1, The above clutch drum A lubrication structure for a clutch for a limited-slip differential, which is coupled and fixed to one side of the differential case and sealed so that lubricating oil inside the friction material is not discharged to the differential case side.
In paragraph 1, The above differential cover is A lubrication structure for a clutch for a limited-slip differential, which is fixed by bolting to one side of the clutch drum.
In paragraph 1, The above differential cover is A lubrication structure for a clutch for a limited-slip differential, wherein a rod hole is formed that penetrates axially opposite the friction material of the clutch unit and is positioned to accommodate a piston rod.
In Paragraph 11, The above road hole is A lubrication structure for a clutch for a limited-slip differential, formed by a circular, elliptical, elongated, or arched through hole to form an oil gap between the piston rod and the hole.

Description

Lubrication structure of clutch for limited slip differential The present invention relates to a lubrication structure for a clutch, and more specifically, to a lubrication structure for a clutch applied to a limited-slip differential that electronically controls the torque distribution between left and right drive wheels. Generally, a vehicle differential is a power transmission device configured between the left and right drive shafts, which are respectively connected to the left and right drive wheels. It absorbs the difference in rotational speed between the left and right drive wheels when a difference occurs due to cornering or uneven road surfaces while driving, thereby enabling smooth driving. FIG. 1 is a cross-sectional view of a differential to which a differential limiting device according to the prior art is applied, and FIG. 2 is a cross-sectional perspective view of a differential carrier applied to a differential limiting device according to the prior art. Referring to FIGS. 1 and 2, a differential (20) according to the prior art includes a ring gear (52), a pair of side gears (54, 56), and a pair of pinion gears (58a, 58b) inside a housing (30). The housing (30) is positioned between the left and right drive shafts, and a pinion shaft (59) on which a pair of pinion gears (58a, 58b) are installed is installed inside the housing (30). The ring gear (52) is fixed to the differential carrier (42) via a bolt (53) and rotates together with the differential carrier (42), and the one-sided side gear (54) is received in the differential carrier (42). When the vehicle is moving straight, the load acting on the left and right drive wheels is the same, and when rotational power is input from the transmission to the ring gear (52), the housing (30) rotates together with a pair of pinion gears (58a, 58b) and rotates a pair of side gears (54, 56) at the same rotational speed to transmit rotational power to the left and right drive wheels. On the other hand, when the vehicle turns or travels on an irregular road surface, the load transmitted through a pair of side gears (54, 56) changes due to the difference in rotational speed between the left and right drive wheels, and accordingly, a pair of pinion gears (58a, 58b) rotate and revolve in a direction that absorbs the difference in rotational speed to transmit rotational power to the left and right drive wheels. Meanwhile, the differential (20) is equipped with a Limited Slip Differential (LSD) to limit the differential function in case the vehicle is driven on a surface with low friction, such as mud, sand, snow, or ice, and the drive wheel on the side with low friction slips and power transmission is not achieved. The trend is to apply an electronic limited-slip differential (e-LSD) that electronically controls the operation of the clutch pack (46) as a representative type of such limited-slip differential. The clutch pack (46) applied to this electronic limited-slip differential is a wet clutch, and in the case of a wet clutch, a plurality of lubrication channels (120) are formed in the carrier portion (82) to supply lubricating oil through oil churning by the rotation of the housing (30) to cool and lubricate the clutch pack (46). However, the clutch applied to the electronic limited-slip differential according to the prior art has a structure in which the lubricating oil supply path flows into the outer diameter side of the friction material, which consists of a clutch disc and a clutch plate, through a lubricating channel (120) on the differential case (i.e., referring to the housing (30)), and has the disadvantage that it is difficult for the lubricating oil to reach the inner diameter side of the friction material due to the centrifugal force of the differential case that is constantly rotating. Accordingly, the inner diameter of the clutch friction material has a high possibility of dry friction, which limits the ability to secure the clutch's performance, durability, and heat resistance. The matters described in this background technology section are written to enhance understanding of the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. These drawings are intended for reference to explain exemplary embodiments of the present invention, and therefore, the technical concept of the present invention should not be interpreted as being limited to the attached drawings. FIG. 1 is a cross-sectional view of a differential limiting device according to the prior art. FIG. 2 is a cross-sectional perspective view of a differential carrier applied to a differential limiting device according to the prior art. FIG. 3 is a cross-sectional view of a drive system for an electric vehicle to which a lubrication structure of a clutch is applied in an embodiment of the present invention. FIG. 4 is a partially enlarged cross-sectional view of an electronic limited-slip