Rolling bearing unit with combination seal ring

Abstract

In order to implement a structure capable of ensuring the movement of a seal lip (22a) provided in a seal ring (17a) by preventing the entry of foreign matter into a seal interior space (26a) between a slinger (16) and the seal ring (17a) which constitute a combination seal ring (12a), a labyrinth seal (27a) is provided between the outer peripheral edge of a rotation-side circular ring section (19) constituting the slinger (16) and the inner peripheral surface of a stationary side cylindrical section (23) of a cored bar (20) constituting the seal ring (17a). Further, in a portion which is a part of an elastic material (21a) constituting the seal ring (17a) and is located between the labyrinth seal (27a) and the seal lip (22a) being a side lip, an auxiliary seal lip (32) having lower rigidity than the seal lip (22a) is provided. The total axial length of the auxiliary seal lip (32) in a free state is set to 5.5 to 7.5 times the thickness thereof, and the proportion of an interference is set to the range of 0-20% of the total axial length in a free state.

Description

technical field [0001] The present invention relates to an improvement of a rolling bearing unit with a composite seal ring, which is used, for example, in a rolling bearing unit for freely rotatably supporting a wheel of an automobile relative to a suspension device, by using an oil flinger and a seal. A rolling bearing unit formed by sealing the end opening of the internal space of the bearing with a combined sealing ring composed of a ring. A plurality of rolling bodies are provided. Background technique [0002] [Description of Prior Art] [0003] As a rolling bearing unit for freely rotatably supporting the wheels and the like of an automobile with respect to the suspension device, for example, Patent Document 1 discloses Figure 7 The structure of the rolling bearing unit for wheel support is shown. Should Figure 7 In the shown rolling bearing unit 1 , an outer ring 2 that is a stationary side raceway ring and a hub 3 that is a rotating side raceway ring are arrange...

AI Technical Summary

Problems solved by technology

However, the technology disclosed in Patent Document 3 is aimed at the side lip that functions to prevent the intrusion of foreign matter into the internal space of the bearing, and it is not possible to apply the value of the appropriate interference amount for such a side lip as it is to a side lip whose overall length is shorter than that of the side lip, Auxiliary lip with small thickness (low rigidity)

In addition, when the value of the interference is set to be large, due to the sliding contact between the tip edge of the auxiliary seal lip and the axially outer surface of the rotation side annular portion constituting the slinger, Frictional resistance, there is a possibility of deformation such as a phase shift (delay) of the terminal part relative to the base end part in the circumferential direction

Furthermore, the full length in the axial direction of the free state of the auxiliary seal lip is L 2 In the case of such deformation, the axial full length of the auxiliary sealing lip from L 2 reduced to L 2 cosα (α: the deviation angle in the circumferential direction between the tip end and the base end), so the actual value of the interference will decrease, and only the sliding torque (sealing torque) will increase.

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