Model Selection - SMC Networks LEJS Series Instructions Manual

Electric Actuator/High Rigidity Slider Type
Ball Screw Drive/

Model Selection

Selection Procedure
Check the speed–work load.
Step 1
Selection Example
Operating
• Work load: 60 [kg]
conditions
• Speed: 300 [mm/s]
• Acceleration/Deceleration: 3000 [mm/s
• Stroke: 300 [mm]
• Mounting orientation: Horizontal
• Motor type: Incremental encoder
• External force: 10 [N]
Step 1 Check the speed–work load.
Select the product by referring to "Speed-Work Load Graph" (Page 12).
Selection example) The LEJS63S3B-300 is temporarily selected based on the
The regeneration option may be necessary.
Refer to page 12 for "Required Conditions for Regeneration Option".
Step 2
Check the cycle time.
Refer to method 1 for a rough estimate, and method 2 for a more precise value.
Method 1: Check the cycle time graph (Page 13)
The graph is based on the maximum speed of each size.
Method 2: Calculation
Cycle time T can be found from the following equation.
T = T1 + T2 + T3 + T4 [s]
• T1 and T3 can be obtained by the following equation.
T1 = V/a1 [s]
The acceleration and deceleration values have upper limits
depending on the workpiece mass and the duty ratio.
Check that they do not exceed the upper limit, by referring
to "Work load–Acceleration/Deceleration Graph (Guide)"
(Pages 15 to 17).
For the ball screw type, there is an upper limit of the speed
depending on the stroke. Check that if it does not exceed
the upper limit, by referring to the specifications (Page 26).
• T2 can be found from the following equation.
L − 0.5 · V
T2 =
• T4 varies depending on the motor type and
load. The value below is recommended.
T4 = 0.05 [s]
Step 3 Check the allowable moment.
Refer to "Dynamic Allowable Moment" graphs (Pages 18 and 19).
Mep
m
L1
Selection example) Select the LEJS63S3B-300 from the graph on the right side.
Confirm that the external force is 20 [N] or less.
(The external force is the resistance due to cable duct, flexible trunking or air tubing.)
11
Series
Check the cycle time.
Step 2
• Workpiece mounting condition:
2 ]
graph shown on the right side.
T3 = V/a2 [s]
· (T1 + T3)
[s]
V
AC Servo Motor
LEJS
Belt Drive/
W
Calculation example)
T1 to T4 can be calculated as
follows.
T1 = V/a1 = 300/3000 = 0.1 [s],
T3 = V/a2 = 300/3000 = 0.1 [s]
L − 0.5 · V · (T1 + T3)
T2 =
V
300 − 0.5 · 300 · (0.1 + 0.1)
=
300
= 0.90 [s]
T4 = 0.05 [s]
Therefore, the cycle time can be
obtained as follows.
T = T1 + T2 + T3 + T4
= 0.1 + 0.90 + 0.1 + 0.05
= 1.15 [s]
LEJB
Series
Check the allowable moment.
Step 3
90
LEJS63
Lead 10:
80
Area where the regeneration
70
option is required.
60
LEJS63
Lead 20:
50
Lead 30:
LEJS63
40
30
20
10
0
0 200 400 600 800 1000 1200 1400 1600 1800
Speed [mm/s]
<Speed–Work load graph>
(LEJS63)
L
a1 a2
T1 T2 T3
T6
L : Stroke [mm]
V : Speed [mm/s]
a1: Acceleration [mm/s 2 ]
a2: Deceleration [mm/s 2 ]
T1: Acceleration time [s]
Time until reaching the set speed
T2: Constant speed time [s]
Time while the actuator is operating at a constant speed
T3: Deceleration time [s]
Time from the beginning of the constant speed operation to stop
T4: Settling time [s]
Time until in position is completed
T5: Resting time [s]
Time the product is not running
T6: Total time [s]
Total time from T1 to T5
Duty ratio: Ratio of T to T6
T ÷ T6 x 100
1,000
5000 mm/s
2
800
10000 mm/s
15000 mm/s
600
20000 mm/s
400
200
100
0
0 10 20 30 40 50 60 70 80
Work load [kg]
<Dynamic allowable moment>
(LEJS63)
B

A

H

Time
[s]
T4 T5
2
2
2