Superior quality Four point angular contact ball bearing QJ318 QJ319 QJ320 QJ321 QJ322 QJ324 QJ326

Efficient Design &Features

Four-point contact ball bearings consist of a row ofballs to handle combined loads on the inner and outer rings.The radius of the ball

groove is slightly larger than the ball radius.Grooves are created from two midpoints.Typically,the contact angle is 35 degrees from the centerline of the circle,but it varies in different models of four-point contact ball bearings.Four-point contact ball bearings are not suitable for compensating for angular misalignment due to shaft deflection.

The inner ring is assembled separately to allow full filling of the balls

while the outer ring can be used to hold the grooves to prevent the

bearing from rotating.Four-point contact ball bearings have reduced friction, so they should not be used if radial loads are present.

Four-point contact ball bearings have athree-step assembly procedure as follows:

Introduce cage in outer ring area

.The ball is pushed into the above cage

The inner ring halves are pushed from both sides.They are not self-

supporting. So insert the plastic into the hole to keep it safe.

Accuracy

The ABEC precision class checks the accuracy of four-point contact ball bearings. You can find four point contact ball bearings in different sizes but each model will provide the highest possible accuracy.

ABEC1bearings are used in oscillating motion with limitedrotation angle, with zero runout for most rotations.This critical condition

requires axial and radial runout to meet ABEC standards.And in other cases, which values can be followed by the bearing constructor.

Accuracy can be improved in different ways.When wobble occurs

(mainly from the rotation of radial runout in atwo-way system),it can cause structural deformation.This happens when the application uses enough space between the balls. In this case,bearing friction may vary. Four point contact ball bearings may have double bearings compared to two rows of balls.

Speed Limits of Four-Point Contact Ball Bearing

Four point contact ball bearings handle slow to average speed

applications.At a given loadthe ball is loaded withtwo sets of contacts. This allows them to rotate around only one axissince they cannot

rotate around both at the sametime.Asfrictionincreasesso doesthe

slip on the contact group,resulting in high speeds.

Speed depends on section size,ball sizeborediameterlubrication type and retainer type.Four-point contact ball bearings perform more

efficiently at pitch speeds of 1100 feet per minute or less.Factors such as preload,lubrication,and separate loads can overcome this limitation to achieve higher speeds.

Maintenance of Four-Point Contact Ball Bearing

Four-point contact ball bearings are very durable and require less

maintenance than other bearings.Grease lubrication is used when two grease fittings are placed 180 degrees apart so that there is adequate passage.However,oil lubrication should be used if the design uses heavy duty full rotation,or if the bearing is placed near other moving parts.

You need to change the lubricant frequently. Holes or fittings in four- point contact ball bearings make relubrication easierespecially when the bearing has integral seals.

Four-Point Contact Ball Bearing Uses Separators

The style and material of separators used in four-point contact ball bearings vary by application.Options for different materialsinclude bronze,steel,phenolic,nylonstainless steel and Teflon.Conrad deep groove bearings are the mostcommon type ofcage.It can be put into the bearing through the gap between the raceways.

Inserting a complete one-piece retainer into a four-point contact ball bearing is not practical because the races are too thin to disassemble and reassembly is complicated with screws and rivets.The reason is

that four-point contact ball bearings require splitting one of the races to insert.

Thereforeconsidering the maximum capacity oflow-speed bearings and ball separation,wire separators are agood choice.Spring separators are used for slow full rotation applications at low

frequencies where low or uniform bearing torque is essential.Springs help keep sliding friction as low as possible.

Applications of Four-Point Contact Ball Bearing

Four-point contact ball bearings have countless advantages and can be used in a variety of applications. It can be used in pumps, car transmissions,steering columns,etc.The following are some of the main applications of

four-point contact ball bearings:

Turbo Retarders

Turbo retarders are used to convert the kinetic energy of a truck into heat so that excessive kinetic energy does not go to waste. A four-point contact ball bearing is used in this application because it requires

limiting high speeds and it can adjust according to rapid speed changes.

Screw Compressors

Screw compressors are used to compress

various gases in the industry at relatively high pressure.These can be air, oxygen, refrigerants,and other gases.Continuous

rotation between two helical screws releases compression.Thefour-point contact ball bearing is used because ofits

ability to accommodate differential pressure between both screw ends that

causes axial forces.The four-point contact ball bearing has stiff bearing arrangements and small axial clearances so it comes in handy in this application to narrow down the gap between two screws

and the compressor housing,etc.

Wind Turbine Gearboxes

Wind turbine gearboxes are used to transfer energy from a slow-motion rotating shaft(typically18r/min)to a generator for high speeds.Agenerator has about 100 times more speed than the

shaft so the four-point contact ball bearing is used because ofits speed factors. Helical gears cause heavy axial loads which need to be considered as well.

Multiphase Pumps

The four-point contact ball bearing accommodates the axial loadsin multiphase pumps.This pump

helps exploit oil fields more efficiently compared to conventional methods.The pump is placed at the bottom of the sea and increases the pressure of the oil gas mixture upstream.Using a four-point contact ball bearing makes multiphase pumps more reliable and durable work.

Railway

A four-point contact ball bearing is used in the railway for gearboxes and traction motors,along with a cylindrical roller.The inner ring halves of the four-point contact ball bearing are coated since the traction motor needs to be protected from the damage that occurs due to current

passage.