Page 311 - MiSUMi 2025

Economy series Runout Tolerance / Precautions Ball Screws Selection Guide Economy series
Ball Screws Ball Screws

Q Use the following steps to select a ball screws suited to the usage criteria.

Step 1 Step 2 Step 3 OK Step 4 OK Step 5
• Check on Operating • Interim Selection • Allowable Axial • Allowable • Life Check Determination
Conditions of Ball Screw Load Check Rotational Speed
Check
NG NG NG

Step 1 Check on Operating Conditions
3 Refer to Operating Conditions below. Unit 3
Item
NO
Ball Screws / Lead Screws 1 Positioning Accuracy mm mm/s 240mm (Stroke) 720mm 1000mm/s Lead Screws Ball Screws /
V
2 Stroke
mm
3 Travel Speeds
4 Drive Motor Speed mm/s 0.15 0.09 0.15 0.51 0.15 0.57 0.15 0.53 s
rpm
0.9
Rolled Ball Screws 6 Mounting Orientation (horizontal or vertical) Time 0.9×3=2.7 4.1 (1 Cycle) 1.4 Screws Rolled Ball
kg
5 Weight of Workpiece and Table
-
7 Life Hours
P.03-009 8 Motion pattern (Duty Cycle Line Diagram) (See Figure 1) - Figure 1 (Ex.) Duty Cycle Line Diagram P.03-009
Precision Ball Screws Consider the applicability of the following items to the conditions confirmed <Impact on Positioning Precision of Axial Clearance> Screws Precision Ball
Interim Selection of Ball Screw
Step 2

operation is performed from the positive direction,
P.03-027 in step 1 and provisionally decide the ball screws. If the ball screw has axial clearance, when positioning P.03-027
because the work does not move even when the
1. Selection of Lead Accuracy of Ball Screws
Ball Screw Supports / Motor Brackets QPrecautions 1 Select the ball screws that satisfies the positioning precision. clearance interval between the theoretical movement Motor Brackets Ball Screw Supports /
screw shaft rotates, a difference occurs in the
Check the following two points.
amount obtained from the revolution speed of the
Lead Accuracy : D For details, see P.B-029 on the Catalog.
screw shaft and the actual movement amount.
Axial Clearance: D For details, see P.B-030 on the Catalog.
P.03-047 (1) If the nut is removed from the screw shaft, the ball will fall off (6) In operation, if there is too much noise or sharp and harsh 2. Selection of Ball Screw Shaft Length Displacement in (+) and (-) directions P.03-047
the nut and cannot be used. Do not disassemble, as this may
sound, please make sure that the installation accuracy of
Lead Screws cause impurities to enter the interior and damage the (7) Although lithium soap-based grease has been applied at Normally, the shaft length is calculated as 2 Stroke + Nut length + Lead Screws
the screw and the specifications of peripheral components
Margin.
assembly accuracy of each part. When the nut needs to be
such as motors and couplings are appropriate.
The margin is the safety allowance for travel exceeding the limit,
removed, use a special auxiliary shaft.
typically taken as 1.5 to 2 times the lead of the screw.
the factory, it is required to apply new grease every 2~3
P.03-058 (2) The outer circle, spiral groove and circulating parts of the (8) Do not let the nut exceed the movement range of the ball 3. Provisional positioning of lead - 0 + P.03-058
months as standard after receiving the goods.
screw shaft will be damaged by external force impact,
Lead Screw Nuts (3) Ball screws and nuts placed with an inclination may fall due to screw nut, or screw out of the screw shaft, otherwise the 4. Temporary selection of the shaft diameter During buckling Nuts Lead Screw
3 Travel speeds, and 4 speed of the drive motor should be used to
resulting in poor circulation and loss of function. Please take
select the lead.
care to avoid it.
ball will fall off and the ball cycling parts will be damaged.
vertical axis, the nuts are likely to fall due to weight. Please set
(10) This product is a machined type, so there will be knife
decided lead should be used to select the shaft diameter.
P.03-077 weight. Please be careful. Especially when it is used as a (9) Nut overstroke operation is prohibited. 5 Weight of work and table, and 6 mounting position, and provisionally P.03-077
up a fall prevention mechanism.
patterns and color difference in its appearance. Small
Lead Screw Supports (4) Please check the flexibility by rotating the screw shaft with the scratches or color changes without affecting the use and The max. axial load to the ball screw must be equal to or less than the Supports Lead Screw
Allowable Axial Load Check
Step 3
fixed nut or rotating the nut with the fixed shaft.
main function are a normal phenomenon. Please feel free
(5) Rotating the nut by hand may not feel smooth, but does not
to use.
P.03-079 affect the positioning precision. Please feel free to use. (11) The noise value of the screw after assembly is not allowable axial load value. If a load exceeding the allowable axial loading is Loading direction P.03-079
guaranteed.
applied, it is possible that the ball screw’s screw shaft will buckle. (Figure 2)
Lead Screw Stop Plates / Position Indicators If the nut end face is moved out of Allowable Axial Load Position Indicators Lead Screw Stop Plates /
The allowable axial load represents an allowed maximum load, including a safety margin, to
the range of right figure, it will
P.03-081 Removal of nut No impact on Be careful of falling Checking by cause the ball to fall off, resulting prevent shaft buckling from occurrence. P.03-081
The finer the shaft diameter or the longer the shaft the easier it is for buckling to occur.
in malfunction.
is prohibited the nut due to weight reverse operation
D For details, see P.B-031 on the Catalog.
Figure 2 Buckled Ball Screw
03-013 03-014