Shaft end finished product precision ball screw (BNK type), shaft diameter 12, lead 2

Brand :

THK

Caution

Some of the items are scheduled to be discontinued as of end of March in 2023. The manufacturer keep the items produced but they are not available with Misumi.
There are not the replacement items and the plan to resumption of sale. Please check the quotation and order screen for details.

Product Description

Because the shaft tips are complete, no drawing and machinery are necessary and the product can be used as is.

[Features]
· The machined screw shaft tip product is standardized ball screw unit with a space saving screw shaft and ball screw nut.
· The screw shaft is standardized with a support unit for the screw tip terminal. When using a BNK0401/0501/0601 mount shape, screws not set as fixed - free are considered fixed - support, and form a direct structure with the motor.
· The screw shaft and ball screw nut shape feature a compact design. In addition, these parts can be assembled in the same shape when used with a support unit or nut bracket, creating a simple and high accuracy feed mechanism.

Drawing

Product Specification

Ball Screw Specifications

lead (mm)	2
BCD (mm)	12.3
Root diameter (mm)	11
Helix Direction, Number of Starts	Right, 1
Number of Circuits	1 turn × 3 rows
Clearance Symbol	G0	GT	G2
Axial clearance (mm)	0	0.005 or less	0.02 or less
Basic dynamic load rating Ca (kN)	1.7	1.7	1.7
Basic static rated load C₀a (kN)	3.6	3.6	3.6
Preload torque (N⋅m)	4.0×10^-3 to 3.4×10^-2	-	-
Spacer ball	Not Included	Not Included	Not Included
Rigidity Value (N/μm)	120
Circulation type	deflector

Specifications Table

Part number	Stroke	Screw shaft length			Screw shaft axis run-out D	Nut outer diameter run-out H	Flange Perpendicularity I	Thread groove surface run-out J	Lead accuracy		Nut Weight kg	Shaft Weight kg/m
Part number	Stroke	L₁	L₂	L₃	Screw shaft axis run-out D	Nut outer diameter run-out H	Flange Perpendicularity I	Thread groove surface run-out J	Actual Mean Travel Error	Variation	Nut Weight kg	Shaft Weight kg/m
BNK 1202-3RRG0+154LC3Y	50	85	99	154	0.02	0.01	0.008	0.007	+/- 0.008	0.008	0.05	0.71
BNK 1202-3RRG0+154LC5Y					0.035	0.012	0.01	0.011	+/- 0.018	0.018	0.05	0.71
BNK 1202-3RRG2+154LC7Y					0.04	0.02	0.014	0.014	travel length error: +/- 0.05/300		0.05	0.71
BNK 1202-3RRG0+204LC3Y	100	135	149	204	0.03	0.01	0.008	0.007	+/- 0.01	0.008	0.05	0.71
BNK 1202-3RRG0+204LC5Y					0.04	0.012	0.01	0.011	+/- 0.02	0.018	0.05	0.71
BNK 1202-3RRG2+204LC7Y					0.055	0.02	0.014	0.014	travel length error: +/- 0.05/300		0.05	0.71
BNK 1202-3RRG0+254LC3Y	150	185	199	254	0.03	0.01	0.008	0.007	+/- 0.01	0.008	0.05	0.71
BNK 1202-3RRG0+254LC5Y					0.04	0.012	0.01	0.011	+/- 0.02	0.018	0.05	0.71
BNK 1202-3RRG2+254LC7Y					0.055	0.02	0.014	0.014	travel length error: +/- 0.05/300		0.05	0.71
BNK 1202-3RRG0+304LC3Y	200	235	249	304	0.04	0.01	0.008	0.007	+/- 0.012	0.008	0.05	0.71
BNK 1202-3RRG0+304LC5Y					0.05	0.012	0.01	0.011	+/- 0.023	0.018	0.05	0.71
BNK 1202-3RRG2+304LC7Y					0.055	0.02	0.014	0.014	travel length error: +/- 0.05/300		0.05	0.71
BNK 1202-3RRG0+354LC3Y	250	285	299	354	0.04	0.01	0.008	0.007	+/- 0.012	0.008	0.05	0.71
BNK 1202-3RRG0+354LC5Y					0.05	0.012	0.01	0.011	+/- 0.023	0.018	0.05	0.71
BNK 1202-3RRG2+354LC7Y					0.065	0.02	0.014	0.014	travel length error: +/- 0.05/300		0.05	0.71

For C3 and C5 accuracy, the GT clearance is also standardized.

Cautions and Prohibitions

Handling

(1) When transporting products weighing 20 kg or more, please use two or more people or use transport equipment. It may cause injury or damage.
(2) Do not disassemble any parts. It may cause loss of function.
(3) Note that, when a ball screw shaft or ball screw nut is tilted, it may be fallen out by its own weight.
(4) Do not drop or hit the ball screw. It may cause injury or damage. Also, please note that when shock was applied, the product may lose its function even though there is no visible damage to the external appearance.
(5) During assembly, make sure not to remove the ball screw nut from the ball screw shaft.
(6) When handling the product, wear protective gloves, safety shoes, and the like as necessary to ensure safety.

Precautions for use

(1) Be careful to prevent the entry of contaminants such as cutting chips or coolant. Otherwise, it may cause damage.
(2) If the product is used in environments where cutting chip, coolant, corrosive solvents, water, etc. may enter the interior, avoid entry into the product by using bellows, cover, or similar protection.
(3) Avoid using the product at temperatures exceeding 80°C. Except for heat resistant specifications, if this temperature is exceeded, resin and rubber parts may be deformed or damaged.
(4) If cutting chip or other contaminant adheres to the product, please clean it and then reapply lubricant.
(5) In cases of slight oscillation, it is difficult for an oil film to form on the contact surfaces between the rolling element and the rolling surface, which may cause fretting. Please use grease with excellent fretting resistance. In addition, we recommend periodically performing an operation equivalent to one rotation of the ball screw nut to form an oil film on the rolling surfaces and rolling elements.
(6) Do not forcibly drive positioning components (such as pins or keys) into the product. This may cause indentations on the rolling surfaces and result in loss of function.
(7) If there is any misalignment or tilting between the ball screw shaft support and the ball screw nut, the lifespan may become extremely short. Please pay close attention to the mounting components and assembly accuracy.
(8) If the rolling element falls out of the ball screw nut, do not use it as is.
(9) When using in a vertical axis, please take measures such as adding a safety mechanism to prevent falling. The ball screw nut may fall by its own weight.
(10) Do not use the product in excess of the allowable rotational speed. May lead to damage to parts or accidents. Please use within our specified rotating speed range.
(11) Do not let a ball screw nut overrun. This may cause balls to fall out, damage to circulation components, or indentations on the ball rolling surface, resulting in malfunction. In addition, continued use in this condition may lead to premature wear or damage to circulation components.
(12) When using the ball screw, please provide guide elements such as an LM guide or ball spline. It may cause damage.
(13) If the rigidity or accuracy of the mounting component is insufficient, the load on the bearing will be locally concentrated, and the bearing performance will be significantly reduced. Therefore, please thoroughly consider the rigidity and accuracy of the housing and base, as well as the strength of the fixing bolts.

Lubrication

(1) Wipe off the anti-rust oil thoroughly and fill with lubricant before use.
(2) Avoid mixing different lubricants. Even if the thickener is the same type of grease, differences in additives and other components may have adverse effects on each other.
(3) When used in special environments such as locations subject to constant vibration, clean rooms, vacuum, or extreme low or high temperatures, please use grease suitable for the specifications and environment.
(4) When lubricating products that do not have a grease fitting or oil hole, apply lubricant directly to the rolling surface and perform several break-in strokes to ensure grease enters the interior.
(5) The consistency of the grease changes depending on the temperature. Please note that changes in consistency will also affect the torque of the ball screw.
(6) After lubrication, the mixing resistance of the grease may cause the rotational torque of the ball screw to increase. Be sure to perform a break-in operation and allow the grease to fully blend in before operating the machine.
(7) Immediately after greasing, excess grease may scatter around the area, so please wipe it off as needed before use.
(8) The properties of grease deteriorate and its lubrication performance declines over time, so it is necessary to inspect and replenish the grease according to usage frequency.
(9) The lubrication interval may vary depending on the usage conditions and operating environment, but as a reference, please lubricate every 100 km of travel (every 3 to 6 months). Please determine the final lubrication interval and amount based on actual machine operation.
(10) Depending on the mounting orientation and the lubrication port of the nut, the lubricant may not circulate properly, resulting in insufficient lubrication. Please consider this carefully during the design stage.
(11) When using a ball screw, it is necessary to ensure proper lubrication. If used without lubrication, wear on the rolling parts may increase and cause premature lifespan reduction. The reference amount of lubrication is indicated in the digital catalog.

Storage

Store ball screws in our packaging and shipping configuration, avoiding high temperatures, low temperatures, and high humidity, and keep them in a horizontal position indoors.
For products stored for a long period, the internal lubricant may have deteriorated over time, so please replenish the lubricant before use.

Disposal

Please dispose of the product appropriately as industrial waste.