Idlers, Backside Belt Tensioning

Brand :
MISUMI
Caution
Product Description
This is an economy item, The price is cheaper than the MISUMI standard product.
Product Overview
Usually, timing pulleys, timing idlers and timing belts are widely used to design mechanisms for transmitting rotational power generated by motors.
During actual assembly, the timing belt can be tensioned using an idler pulley for rear tensioning.
During actual assembly, the timing belt can be tensioned using an idler pulley for rear tensioning.
Dimensional Drawing

Bearing is pressed fit.
Bearing accuracy JIS B1514 Class 0 / GB T 307-94 P0 (before press-fitting).
MISUMI does not guarantee the bearing brand.Material Specifications
| Type | Material | Surface Treatment | |||
| Without Flange | With Flange | Body | Flange | Bearing | |
| E-AFBD | E-AFDF | Aluminum | Aluminum | Steel | Clear Anodized |
| E-BFBD | E-BFDF | General structural steel or carbon steel | SPCC | Black Oxide | |
| E-MFBD | E-MFDF | Electroless Nickel Plating | |||
| E-SFBD | E-SFDF | Austenitic Stainless Steel | Austenitic Stainless Steel | - | |
If rust prevention is required, please give priority to products made of aluminum alloy, austenitic stainless steel, or with electroless nickel plating surface treatment.Please click
Anti-rust performance and maintenance of metal materials and surface treatment.Specification Table
■ Size Specification Table - Center Bearing Type
All specifications marked with * are only applicable to E-AFBD and E-AFDF.
■ Size Specification Table - Double-Sided Bearing Type
MISUMI does not guarantee the bearing brand
| Part Number | D | F | A | Applicable Belt Nominal Width | S | Bearing size | Buckle used | |||||
Type | W | Inch | mm | No. | d | B | E-AFBD E-MFBD E-SFBD E-AFDF E-MFDF E-SFDF | E-BFBD E-BFDF | ||||
| No Flange E-AFBD E-BFBD E-MFBD E-SFBD With Flange E-AFDF E-BFDF E-MFDF E-SFDF | 9 | 20* | 25 | 5 | - | 040 | 2.5 | 695ZZ | 5 | 4 | RTWS13 | RTWN13 |
| 25 | 30 | |||||||||||
| 10 | 25* | 30 | 6 | 019 | - | 2.5 | 696ZZ | 6 | 5 | RTWS15 | RTWN15 | |
| 11 | 25 | 30 | 7 | - | 060 | 3.0 | 696ZZ | 6 | 5 | RTWS15 | RTWN15 | |
| 11.5 | 25 | 30 | 7.5 | 025 | - | 3.25 | 696ZZ | 6 | 5 | RTWS15 | RTWN15 | |
| 14 | 30* | 35 | 9 | 031 | 4 | 698ZZ | 8 | 6 | RTWS19 | RTWN19 | ||
| 15 | 30 | 35 | 11 | 037 | 100 | 4.5 | 698ZZ | 8 | 6 | RTWS19 | RTWN19 | |
| 16 | 40 | 48 | 4 | 6000ZZ | 10 | 8 | RTWS26 | RTWN26 | ||||
| 19 | 30* | 36 | 14 | 050 | - | 6.5 | 698ZZ | 8 | 6 | RTWS19 | RTWN19 | |
| 35 | 45 | 5.5 | 628ZZ | 8 | 8 | RTWS24 | RTWN24 | |||||
| 45 | 55 | 5 | 6200ZZ | 10 | 9 | RTWS30 | RTWN30 | |||||
| 22 | 35* | 45 | 17 | - | 150 | 7 | 6000ZZ | 10 | 8 | RTWS26 | RTWN26 | |
| 45 | 55 | 6.5 | 6200ZZ | 10 | 9 | RTWS30 | RTWN30 | |||||
| 26 | 40* | 48 | 21 | 075 | - | 9 | 6000ZZ | 10 | 8 | RTWS26 | RTWN26 | |
| 45* | 55 | 8.5 | 6200ZZ | 10 | 9 | RTWS30 | RTWN30 | |||||
| 50 | 58 | 8.5 | 10 | |||||||||
All specifications marked with * are only applicable to E-AFBD and E-AFDF.■ Size Specification Table - Double-Sided Bearing Type
| Part Number | Nominal model | D | F | A | Applicable Belt Nominal Width | Bearing size | ||||
Type | W | Inch | mm | No. | d | B | ||||
| No Flange E-AFBD With Flange E-AFDF | 9 | 15 | 15 | 18 | 5 | - | 040 | 675ZZ × 2 | 5 | 2.5 |
| 20W | 20 | 25 | 676ZZ × 2 | 6 | 3 | |||||
| 11 | 15 | 15 | 18 | 7 | 060 | 675ZZ × 2 | 5 | 2.5 | ||
| 20 | 20 | 25 | 676ZZ × 2 | 6 | 3 | |||||
| 11.5 | 15 | 15 | 18 | 7.5 | 025 | - | 675ZZ × 2 | 5 | 2.5 | |
| 20 | 20 | 25 | 676ZZ × 2 | 6 | 3 | |||||
| 15 | 20 | 20 | 25 | 11 | 037 | 100 | 686ZZ × 2 | 6 | 5 | |
| 25 | 25 | 30 | 688ZZ × 2 | 8 | 5 | |||||
| 19 | 25 | 25 | 32 | 14 | 050 | - | 688ZZ × 2 | 8 | 5 | |
| 30W | 30 | 36 | 688ZZ × 2 | 8 | 5 | |||||
| 22 | 25 | 25 | 32 | 17 | - | 150 | 688ZZ × 2 | 8 | 5 | |
| 35W | 35 | 45 | 6000ZZ × 2 | 10 | 8 | |||||
| 26 | 40W | 40 | 48 | 21 | 075 | - | 6000ZZ × 2 | 10 | 8 | |
| 45W | 45 | 55 | 6201ZZ × 2 | 12 | 10 | |||||
| 27 | 60 | 60 | 67 | 22 | - | 200 | 6201ZZ × 2 | 12 | 10 | |
| 32 | 45 | 45 | 55 | 27 | 100 | 250 | ||||
| 65 | 65 | 74 | 27 | |||||||
| 37 | 55 | 55 | 67 | 32 | - | 300 | ||||
| 65 | 65 | 74 | 32 | |||||||
| 45 | 70 | 70 | 80 | 40 | 150 | - | 6202ZZ × 2 | 15 | 11 | |
| 49 | 60 | 60 | 67 | 44 | - | 400 | ||||
| 70 | 70 | 80 | 44 | |||||||
| 58 | 60 | 60 | 67 | 53 | 500 | |||||
| 59 | 70 | 70 | 80 | 54 | 200 | - | ||||
MISUMI does not guarantee the bearing brandProduct Features
Feature 1: MISUMI tension idler for the back of timing belts, suitable for all types of toothed belts.
Feature 2: MISUMI synchronous belt tensioning idler on the back does not contact the toothed surface, greatly reducing wear on the toothed surface.
Feature 3: MISUMI timing belt tensioning idler does not contact the toothed surface and allows flexible adjustment of the tensioning position.
Feature 4: MISUMI timing belt tensioning idler can be installed on the slack side near the pulley to increase the belt wrap angle.
Feature 5: MISUMI timing belt idlers comply with industry standards, ensuring stable procurement and easy equipment maintenance.
Feature 6: MISUMI timing belt idlers are available in a variety of materials to suit different designs and usage environments.
Feature 2: MISUMI synchronous belt tensioning idler on the back does not contact the toothed surface, greatly reducing wear on the toothed surface.
Feature 3: MISUMI timing belt tensioning idler does not contact the toothed surface and allows flexible adjustment of the tensioning position.
Feature 4: MISUMI timing belt tensioning idler can be installed on the slack side near the pulley to increase the belt wrap angle.
Feature 5: MISUMI timing belt idlers comply with industry standards, ensuring stable procurement and easy equipment maintenance.
Feature 6: MISUMI timing belt idlers are available in a variety of materials to suit different designs and usage environments.
Usage Method
| Usage Method Example Drawing | How to Use the Idler Pulley for Tensioning the Back of the Timing Belt |
![]() | When using a back tension idler on the outside, the pulley diameter should be at least 20% larger than the minimum pulley diameter specified in the product catalog. (1) When using a tension idler on the outside, it should be positioned close to the large pulley. (2) The bending angle of the machine belt should be greater than 140#. (3) The tension idler should use a flat pulley without protrusions. (4) Please do not use an idler pulley for tensioning on the back side of polyurethane belts. |
Precautions
(1) If rust prevention is required, please give priority to products made of aluminum alloy, austenitic stainless steel, or with electroless nickel plating surface treatment.
Please click
Rust Prevention and Maintenance of Metal Materials and Their Surface Treatments
(2) Do not use an idler pulley for tensioning on the back side of polyurethane timing belts.
Please click
Rust Prevention and Maintenance of Metal Materials and Their Surface Treatments(2) Do not use an idler pulley for tensioning on the back side of polyurethane timing belts.
Example of Use

■Organization Name
Belt Tensioner (Manual)
■ Mechanism Function
1. Moves the roller on the adjustment side to tighten and secure it while the conveyor belt is open.
2. When using multiple drives, increase the engagement rate by setting the roller to the center position.
■ Function of the Timing Belt Idler Pulley
1. The timing belt idler pulley fixes the assembly distance of the belt
and also assists the polyurethane roller in tensioning the belt
Belt Tensioner (Manual)
■ Mechanism Function
1. Moves the roller on the adjustment side to tighten and secure it while the conveyor belt is open.
2. When using multiple drives, increase the engagement rate by setting the roller to the center position.
■ Function of the Timing Belt Idler Pulley
1. The timing belt idler pulley fixes the assembly distance of the belt
and also assists the polyurethane roller in tensioning the belt
Related Industries
Related Products
| Idlers for Flat Belts Width (T) 6 to 32 mm | Flat Belts for General Use | High Torque Timing Pulleys S2M Type | ||
![]() | ![]() | ![]() | ||
| Typical model: HBG15-6 | Typical model: HBLT350-4.23 | Typical model: HTPA48S2M040-B-N10 | ||
| Advantages: short delivery time, multiple types | Advantage: custom size | Advantages: short delivery time, multiple types |
Related Documents
Timing Belts, Timing Pulleys, Idler Technical Information
(1) Information on selecting timing pulleys and timing belts, tension, etc. (Transmission).
(2) Selection data for timing pulleys and timing belts, tension data, etc. (Transmission and conveying).
(3) Main causes and countermeasures for synchronous timing belt damage, breakage, abnormal noise, etc.
(4) Reference materials on timing belt replacement intervals.
(5) Timing pulley and idler dimension tolerance information.
(1) Information on selecting timing pulleys and timing belts, tension, etc. (Transmission).
(2) Selection data for timing pulleys and timing belts, tension data, etc. (Transmission and conveying).
(3) Main causes and countermeasures for synchronous timing belt damage, breakage, abnormal noise, etc.
(4) Reference materials on timing belt replacement intervals.
(5) Timing pulley and idler dimension tolerance information.
Material
Surface Treatment
D
Type
W








