Square Type Support Unit
Example of Installing a Square Type Support Unit
Round Type Support Unit
Example of Installing a Round Type Support Unit
Structure and Features
The Support Unit comes in six types: models EK, FK, EF, and FF, which are standardized for standard-stock Ball Screws provided with finished shaft ends, and models BK and BF, which are standardized for ball screws in general.
The Support Unit on the fixed side contains a JIS Class 5-compliant angular bearing provided with an adjusted preload. The miniature type Support Unit models EK/FK 4, 5, 6 and 8, in particular, incorporate a miniature bearing with a contact angle of 45゜developed exclusively for miniature
Ball Screws. This provides stable rotation performance with high rigidity and accuracy.
The Support Unit on the supported side uses a deep-groove ball bearing.
The internal bearings of Support Unit models EK, FK and BK contain an appropriate amount of lithium soap-group grease that is sealed with a special seal. Thus, these models are capable of operating over a long period.
Uses the Optimal Bearing
To ensure rigidity balance with the Ball Screw, the Support Unit uses an angular bearing (contact angle: 30゜; DF configuration) with high rigidity and low torque. Miniature Support Unit models EK/FK 4, 5, 6 and 8 are incorporated with a miniature angular bearing with a contact angle of 45゜developed exclusively for miniature Ball Screws. This bearing has a greater contact angle of 45゜and an increased number of balls with a smaller diameter. The high rigidity and accuracy of the miniature angular bearing provides stable rotation performance.
Support Unit Shapes
Square and round shapes are available for the Support Unit to allow selection according to the intended use.
Compact and Easy Installation
The Support Unit is compactly designed to accommodate the space in the installation site. As the bearing is provided with an appropriately adjusted preload, the Support Unit can be assembled with a Ball Screw unit with no further machining. Accordingly, the required man-hours in assembly can be reduced and the assembly accuracy can be increased.
Installing the Support Unit
① Install the fixed-side Support Unit with the screw shaft.
② After inserting the fixed-side Support Unit, secure the lock nut using the fastening set piece
and hexagon socket setscrews.
③ Attach the supported-side bearing to the screw shaft and secure the bearing using the snap
ring, and then install the assembly to the housing on the supported side.
Note 1: Do no disassemble the Support Unit.
Note 2: When inserting the screw shaft to the Support Unit, take care not to let the oil seal lip turn outward.
Note 3: When securing the set piece with a hexagon socket screw, apply an adhesive to the hexagon socket screw before
tightening it in order to prevent the screw from loosening. If planning to use the product in a harsh environment, it is
also necessary to take a measure to prevent other components/parts from loosening. Contact for BUN details.
Installation onto the Table and the Base
① If using a bracket when mounting the ball screw nut to the table, insert the nut into the
bracket and temporarily secure it.
② Temporarily secure the fixed-side Support Unit to the base.
In doing so, press the table toward the fixed-side Support Unit to align the axial center, and
adjust the table so that it can freely travel.
●If using the fixed-side Support Unit as the reference point, secure a clearance between the
ball screw nut and the table or inside the bracket when making adjustment.
●If using the table as the reference point, make adjustment either by using the shim (for a
square type Support Unit), or securing a clearance between the outer surface of the nut
and the inner surface of the mounting section (for a round type Support Unit).
③ Press the table toward the fixed-side Support Unit to align the axial center. Make adjustment
by reciprocating the table several times so that the nut travels smoothly throughout
the whole stroke, and temporarily secure the Support Unit to the base.
Checking the Accuracy and Fully Tightening the Support Unit
While checking the run-out of the ball screw shaft end and the axial clearance using a dial
gauge, fully tighten the ball screw nut, the nut bracket, the fixed-side Support Unit and the supported-
side Support Unit, in this order.
Connection with the Motor
① Mount the motor bracket to the base.
② Connect the motor and the ball screw using a coupling.
Note: Make sure the mounting accuracy is maintained.