Adapter Sleeve (Mounting Sleeve)
1. What is it?
An adapter sleeve is a cylindrical sleeve featuring a tapered outer surface and a cylindrical inner bore. One end typically features a protruding flange, while the other end is threaded. It is used in conjunction with a lock nut and a locking washer (commonly referred to as a lock tab washer).
Working Principle: The adapter sleeve is fitted onto the shaft, and the bearing is then mounted onto the tapered surface of the sleeve. By tightening the lock nut, the adapter sleeve is drawn toward the smaller-diameter end of the bearing's inner ring. Due to the tapered fit, the sleeve is compressed axially while simultaneously expanding radially outward; this firmly secures the bearing's inner ring to the shaft and ensures precise radial positioning.
2. Designation Codes
Adapter sleeve designations adhere to specific standards (such as ISO standards) and typically begin with the letter "H," followed by a series of numbers indicating the applicable shaft diameter range.
Format: H 2xxx, AH 2xxx, etc.
H: Denotes an adapter sleeve.
2xxx: The numerical portion, which typically indicates the nominal shaft diameter (d) for which the sleeve is intended. For example, H 2316 indicates that this adapter sleeve is suitable for a shaft diameter of d = 80 mm.
Specific codes should be verified by consulting the product catalog, as the correspondence between the numerical designation and the shaft diameter is standardized.
3. Primary Functions
Bearing Mounting: Securely fixes a tapered-bore bearing onto a smooth (cylindrical) shaft.
Clearance Adjustment: By adjusting the tightness of the lock nut, the bearing's radial internal clearance can be finely tuned-a critical factor for the bearing's performance and service life.
Simplified Installation: Eliminates the need to machine a tapered shoulder onto the shaft, thereby reducing the complexity and cost of shaft manufacturing.
Ease of Maintenance: When a bearing requires replacement, the lock nut simply needs to be loosened to allow for the simultaneous removal of both the bearing and the adapter sleeve.
Installation Direction: Installed by moving from the smaller-diameter end of the bearing toward the larger-diameter end. The nut is tightened to draw the sleeve into the bearing bore, thereby achieving a secure fit.
Withdrawal Sleeve (Dismounting Sleeve)
1. What is it? The withdrawal sleeve is also a tapered sleeve, but its structure is the reverse of that of an adapter sleeve. Its outer surface is conical, while its inner bore is cylindrical. It lacks a flange or threads on its body and typically requires the use of a lock nut in conjunction with a specialized withdrawal nut (also known as a removal nut).
**Working Principle:** During installation, the withdrawal sleeve is first inserted into the bore of the bearing; the combined assembly is then pushed to a predetermined position on the shaft (typically located against a shaft shoulder). Next, a lock nut at the opposite end of the shaft is tightened to press the withdrawal sleeve into the bearing bore, causing it to expand and thereby secure the bearing in place. During removal, a separate removal nut is threaded onto the end of the withdrawal sleeve to "push" or eject it out of the bearing bore.
**2. Designation Code**
The designation code for a withdrawal sleeve typically begins with the letters "AH," followed by a series of numbers.
**Format:** AH 2xxx, W 2xxx, etc.
**AH/W:** Denotes a withdrawal sleeve.
**2xxx:** Indicates the nominal shaft diameter (*d*) for which the sleeve is suitable. For example, AH 318 is suitable for a shaft diameter of *d* = 90 mm.
**3. Primary Functions**
**Bearing Retention:** Serves to secure a tapered-bore bearing onto a smooth (cylindrical) shaft.
**Axial Positioning:** Typically employed in situations where obstacles exist on both sides of the bearing housing, or where a shaft shoulder cannot be utilized for positioning. In such cases, the bearing and withdrawal sleeve are slid onto the shaft from the shaft end until they reach the designated position.
**Ease of Removal:** Its greatest advantage is the extreme ease with which it can be removed. In confined spaces where it is not possible to pull the bearing off the shaft end, one simply needs to tighten the removal nut to eject the withdrawal sleeve from the bearing bore; this releases the bearing, allowing it to be easily detached.
**Installation Direction:** Installation proceeds from the large-diameter end of the bearing toward the small-diameter end. The nut is used to press the sleeve into the bearing bore, thereby achieving a secure fit.
