Angular Ball Bearing Seal Structure to Prevent Ring and Cage Contact
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Solution Overview
Problem
Existing spindle devices with angular contact ball bearings face issues where the sealing member can deform or become inclined due to air flow, leading to potential contact with the inner ring or cage, resulting in increased torque and damage.
Innovation Solution
The angular contact ball bearing features a counter bore on the inner ring and a sealing member with a disk portion and inclined portion that prevents interference with the cage and inner ring, ensuring non-contact and maintaining lubrication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing member is provided on the bearing back surface side, then grease sealing is improved, but the sealing member may contact the inner ring or cage due to air flow or attachment deviation, causing increased torque or damage
Solution Approach 1:
The sealing member is designed with a stepped configuration including a disk portion and an inclined portion that slopes upward in the radial direction. This three-dimensional structure creates clearance in the axial direction between the sealing member and the cage/inner ring, preventing contact while maintaining effective grease sealing at the bearing back surface.
Solution Approach 2:
The air flow path is configured to supply air to the bearing front surface side before the sealing member location, creating a positive air pressure that prevents air from reaching and deforming the sealing member from the rear. This preliminary action protects the sealing member from air-induced deformation before it can occur.
2Object-affected harmful factors
If air flow path is opened for air purge, then prevention of cutting water and dust entry is improved, but air flow may deform the sealing member and cause contact with adjacent components
Solution Approach 1:
The air flow path is specifically directed to the bearing front surface side, creating a localized positive air pressure zone at the front of the bearing. This localized air cushion prevents cutting water and dust from entering the bearing while avoiding direct air flow onto the sealing member at the rear, thus maintaining sealing member position stability.
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
In an inner ring (12), a counter bore (12b) is formed on the bearing back side with respect to an inner ring raceway surface (12a), and the minimum outer diameter (D1) of the counter bore (12b) is smaller than the outer diameter (D) of a shoulder portion (12c) on the bearing front side with respect to the inner ring raceway surface (12a). In addition, a sealing member (15) fixed to the bearing back side of an outer ring (11) is provided with: a disk portion (23); and at least one annular inclined portion (24) that is inclined toward the center of an angular ball bearing (10) in the axial direction, while extending from the disk portion (23) toward the radially inner side. The maximum diameter (D4) of the inclined portion (24) on the axially inner surface side of the sealing member (15) is smaller than the inner diameter (D5) of a holder (14) on a bearing back side end surface (14b). The maximum diameter (D3) of the inclined portion (24) on the axially outer side of the sealing member (15) is larger than the outer diameter (D) of the shoulder portion (12c) on the bearing front side of the inner ring (12) in the angular ball bearing (10).