Track rollers, rollers followers and cam followers have a thick-walled outer ring and belong to the group of rolling bearings. They can be used with or without an inner ring. Single row track rollers are designed like deep groove ball bearings and double row track rollers like angular contact ball bearings. Roller followers are compact, highly rigid bearings that can support significantly higher radial loads than track rollers. Cam followers are roller followers with a solid pin (roller stud) which helps them to be mounted in a simple and compact manner. In contrast to ball bearings, no balls are used as rolling elements here, but rollers or needles.
Roller followers are compact, highly rigid single or double row units mounted on axles. They consist of thick-walled outer rings with a profiled outside surface and needle roller and cage assemblies or full complement or full complement needle roller and cage inserts. The bearings are available in open or sealed versions.
Cam followers are also compact and highly rigid bearings. They consist of thick-walled outer rings with a profiled outside surface, a solid pin (roller stud) with a fixing thread, thrust washers and needle roller and cage assemblies or full complement or full complement single or double row rolling element sets. The bearings are available in several designs with and without eccentrics.
Both bearings tolerate axial loads from misalignment, small misalignments and/or short start-up shocks.
In addition to our own ASK cam and roller followers, we have been the trading partner of the American manufacturer McGill for many years, which has launched a metric product range for the european market. The main dimensions are the same for both brands, so the products are interchangeable. The surface of McGill cam and roller followers are burnished.
Cam and roller followers can support high radial loads as well as axial loads resulting from small misalignments and skewing. They are used so that they roll on a surface plane, a curved track or a mating roller. They are used in cam gears, guideways, conveyor systems, automatic machines, machining centers, feeding machines, etc.
Technical basics of ASK cam followers
Our ASK Cam and roller followers as well as McGill Cam and roller followers have a wide range of applications and can be found wherever rolling on a track is involved, e.g. in materials handling. They can support high loads in the radial direction and also reduce bending stresses.
ASK series
ASK cam and roller followers are manufactured in various series.
Cam followers crowned version
KR: cage guided
KRV: full-blown
PP: double-sided sealing
SK: hexagon socket
Roller followers crowned version
NATR: cage guided
NATV: full-blown
PP: double-sided sealing
McGill series
McGill cam and roller followers are manufactured in various series.
Cam followers with crowned shell
MCF: full-blown
MCFR: cage guided
MCFE: full-blown with eccentric
MCFRE: cage guided with eccentric
Suffix:
-S: with lipped seal
-B: with hexagon socket
-X: with cylindrical shell
Cam followers solid design, full complement, capped, with crowned shell
MCFD
Suffix:
-B: with hexagon socket
-X: with cylindrical shell
Roller followers with crowned shell
MCYR: full-blown
MCYRR: cage guided
Suffix:
-S: with lipped seal
-X: with cylindrical shell
Roller followers solid design, full complement, capped, with crowned shell
MYCRD
Suffix
-X: with cylindrical shell
Load capacities
The basic load ratings or the dynamic basic load ratings are specified in the ISO standards. According to this, 90% of a number of identical bearings must achieve a theoretical life of 1 million revolutions with the outer ring stationary (331/3 rpm on 500 hours). The basic load rating is only a guide; the reference value of 1 million revolutions was chosen for easier calculation. The dimension tables contain the dynamic (C) and static (Co) basic load ratings, calculated according to ISO standards. Also included are the basic dynamic and static load ratings valid for the use of cam followers and roller followers as track rollers. These basic dynamic and static load ratings are lower than the basic dynamic and static load ratings (C and Co); since the outer ring is not supported in this application, and the bearing is subjected to additional bending stress. The bearing load under dynamic stress should not exceed 50% of the basic dynamic load rating (use as a track roller).
Bearing capacity of the raceway
The load carrying capacity of the raceways of all cam followers and roller followers is determined by the load to which a raceway with a given tensile strength can be continuously subjected without deformation of the same. Therefore, for designs with crowned shells as well as raceways made of steel, the minimum hardness of the raceway should be HRC 40 (tensile strength 1242 Mpa). Regardless of the raceway bearing capacity, the bearing load under dynamic load should not exceed 50% of the basic dynamic load rating (use as a track roller), and the static load should not exceed the maximum static load rating (use as a track roller).
Service life
The nominal bearing fatigue life L10 can be calculated according to the following formula:
The required dynamic base load rating for a given application is calculated as follows:
Assembly
When mounting the ASK bearings, ensure that the following is observed:
• The housing that holds the cam follower pin or the shaft on which the roller follower is mounted must be strong enough to withstand excessive deformation and deflection under the expected load.
• The housing face must be flat and right-angled to the housing bore and have a diameter at least equal to the dimension tables so that the bearing thrust washer receives appropriate support.
• Optimum support is achieved when the bevel does not exceed 0.5 mm x 45.
•When mounting cam followers in a machine, the radial lubrication hole should be located in the unloaded part of the raceway.
•The pressure required for assembly should be applied to the fixed, inner part of the integral bolt and not to the edge of the thrust washer. The nut of the cam follower should be tightened so that the thrust washer is securely supported.
• It must be taken care of that the fastening nut is not overtightened, otherwise excessive stresses may occur in the bolt. The fastening nut should not be tightened beyond the maximum torque values specified in the dimension table.
• Roller followers should be mounted with the lubrication hole in the unloaded part of the raceway and according to the shaft diameters as specified in the table values.
• If a tighter bearing fit is required on the shaft, it should be a J6 fit to ISO.
• When used under heavy load, the bearing must be axially clamped and mounted on a quenched and tempered shaft with a tolerance of J6 according to the ISO standard.
•If the bearing cannot be axially clamped, care must be taken to ensure a tight axial fit in the mounting in which the bearing is fitted. This is to prevent axial displacement of the thrust washers under load.
Lubrication
Relubrication for ASK Cam Followers
The cam followers of sizes 13, 16 and 19 do not have a relubrication facility. The KR 22 and KR 26 versions have a relubrication hole on the frontal area on the collar side. Sizes 22 to 32 are supplied with enclosed nut, blind plug and grease nipple. The KR 30 and KR 32 versions have a through lubrication hole and an additional hexagon socket at the bolt end. The KRV version from size 22 has a through lubrication hole and an additional hexagon socket at the bolt end ASK cam followers are lubricated with lithium-based lubricants. (e.g. Shell Alvania RL).
Relubrication option for ASK roller followers
Roller followers have a lubrication hole in the bore of the inner ring so that relubrication can be carried out through a transverse bore of the shaft if required. ASK roller followers are lubricated with lithium-based lubricants. (e.g. Shell Alvania RL).
Tolerances
ASK Cam Followers Standard Version
ASK Roller Followers Standard Version
Use on a flat track
Cam followers and roller followers are one component of a bearing design consisting of two elements. The second component is the flat track or cam disc on which the bearings move. Therefore, a suitable selection of the material for the track or cam disc must be ensured. This has a direct effect on the life and effectiveness of the cam follower application.
If the bearings are used as guide rollers, it is often difficult to achieve high hardness and tensile strength for all machine parts that are used against the bearings. In the economic interest, a relatively soft-textured material can be used for most applications where dimensional accuracy is not extremely critical. A track of cold-hardened iron with a low carbon content will generally provide satisfactory operation of the bearing, with little wear of the track by the bearing. When cam followers and roller followers are used (e.g. in lifting equipment), it is common to use sectional steel rails as bearing tracks. Here, hardening of the track surface and low wear of the track have proved successful, provided that no excessive loads occur.
Use on a cam disc
Applications on a cam disc are similar in many respects to applications on a flat track except for the increased speed due to the multiplication of revolutions per minute of the cam disc by the quotient of the outer diameter of the cam disc to the outer diameter of the bearing used. Due to the increased speed, oil lubrication is preferable. If such lubrication is not available, regreasing must be carried out regularly.
When used in cams with a milled cam profile, there is a possibility of different rotation of the bearing outer ring, as well as a load reversal depending on this. This can lead to excessive wear of the cam plate or bearing. To prevent this, the appropriate hardness must be used for the cam and bearing, and ample lubrication must be provided. In enclosed applications of this type, the pitch and slope of the cam must be closely monitored, as the impinging load reversal may cause excessive shock loading of the pin or bearing. The same precautions should be applied to ordinary circular cams. Momentary loads due to rapid cam slopes must be carefully calculated and below the maximum strength of the pin or bearing.
In ordinary cam designs, it is possible to use the best performing material for best resistance to material fatigue. The goal to be achieved is high hardness and good wear resistance of the track surface. The same general precautions regarding tensile strength as listed under "Use on a Flat Track" should also be observed here. For applications with high marginal loads on the cam or bearing, please contact the manufacturer.
Load bearing capacity of the track
The load carrying capacity of the tracks of all cam followers and roller followers is determined by the load to which a track with a given tensile strength can be continuously subjected without deformation of the same. Therefore, for designs with crowned shells as well as tracks made of steel, the minimum hardness of the track should be HRC 40 (tensile strength 1242 Mpa). Regardless of the track load carrying capacity, the bearing load under dynamic load should not exceed 50% of the basic dynamic load rating (use as a track roller), and the static load should not exceed the maximum static load rating (use as a track roller).