Sprockets Nominal No.20B

Brand :

MISUMI

Caution

Product Description

Economy series B series sprockets should not be matched with A series chains. Please note that some yellow anti-rust oil may be adhered on the surface of the delivered sprocket, which does not affect the use and can be cleaned by yourself.

Product Overview

■ Sprocket is a solid or spoked gear that engages with a roller chain to transfer motion or power.
Application of sprocket: It is widely used in mechanical transmission in chemical industry, textile machinery, food processing, instrumentation, and petroleum industries.

■Only sprockets and chains with the same specifications can be used in combination.
This series is ANSI 20B sprocket, and can be used in combination with our 20B series chain.
■ Do not use it with ISO/ANSI 20 A series chain, which may cause the chain sprocket mechanism to fail to function properly!
The surface of the delivered sprocket may have yellow anti-rust oil attached. This does not affect usage and can be cleaned off if desired. Please take note.
■ Due to process reasons, it is impossible to guarantee the coincidence of the tooth tops of multiple sprockets. If you need to use the tooth tops in an overlapping manner, please contact us.

Dimensional Drawing

External Dimensions (Unit: mm)
Sprockets processed by shaft hole and keyway. *This product is B series European Standard sprocket, and can not be used in combination with American Standard 20 A series sprocket.
■ A single package label may not match the ordered model. It is a factory-managed model. Please note that the outer package label shall prevail!
■ The engraving of sprocket body may be different from the ordered model, please check the engraving number.

20B Dimensional Drawing

Material Specifications

Material	Surface Treatment	Accessories
Equivalent to S45C (Induction Hardened Teeth Tip)	－	Fixing Screw (Only Shaft Hole Specifications N)

*This series is 20B European Standard sprocket, and can not be used in combination with American Standard 20 A series sprocket.

Specification Overview

Specification Table

Part Number				Hole Specifications	Shaft Bore Diameter (D)							Dp	D_O	H	L
Type	Nominal model	Hub type	Number of Teeth (T)	Hole Specifications	S Specification (H8)	N Specifications (H7)						Dp	D_O	H	L
C-SPB	20	B	10	S N	20	25	30					102.74	117	70	40
			11			25	30					112.68	127	77	45
			12				30	35				122.68	137	88
			13				30	35	40			132.65	147.5	98
			14					35	40	45	50	142.68	157.6	108
			15						40	45	50	152.72	167.7	118
			16						40	45	50	162.75	177.7	120	50
			17		25					45	50	172.78	187.8
			18							45	50	182.85	197.8
			19							45	50	192.91	207.9
			20							45	50	202.98	217.9

■ A single package label may not match the ordered model. It is a factory-managed model. Please note that the outer package label shall prevail!

■ Shaft Hole Machining Size Table

Shaft Hole Diameter D	Keyway b₂ × t₂	Fixing Screw M
25 to 30	8 × 3.3	8
32 to 38	10 × 3.3	8
40·42	12 × 3.3	8
45·50	14 × 3.8	10

Product Features

■Sprocket chain drive has the following features compared with gear drive and belt drive:
1. Multi-tooth load bearing, safe and reliable;
2. Flexible transmission, absorbing shock and vibration;
3. Large center distance range, low manufacturing and installation accuracy requirements;
4. Compared with belt drive, the transmission ratio is accurate and the transmission efficiency is higher, suitable for high temperature, dusty and humid environments.

■ Sprocket, chain selection
Misumi’s sprocket and chain product selection supports the principle of “Nominal Numbering”
Product Features

Usage Method

How to mount the roller chain
(A) Shaft arrangement
■ Horizontal
Even when configured as two horizontal axes, the rotation direction of the axes must still be considered.
The examples (2) and (3) in the diagram show that when the chain is stretched, the disengagement between the sprocket teeth and the chain is not smooth and may bite.
In particular, the upper and lower chains in (3) will contact each other, so an idler is required.

■Vertical
If the chain is stretched, slack as shown in (5) will occur, and
when a small sprocket is used on the lower side, the chain may fall off. Therefore, please use it at an angle of 60 or less as shown in (4).
When it is necessary to use it vertically due to the mechanism or space, it is recommended to put the large sprocket on the lower side, and use the idler on the outside or inside as shown in (6).

(B) Deflection
Deflection is generally about 4% of the shaft spacing, and about 2% in the following cases.
a. Vertical transmission or close to vertical transmission
b. Shaft spacing is more than 1m
c. When frequent heavy load starting and stopping are required
d. When reverse rotation is required

(C)When the load changes
If a tension adjuster is mounted on the tension side or slack side of the chain to provide initial tension in advance, it will eliminate vibration and reduce noise during operation.

Precautions

■ Sprocket maintenance
1. Sprocket tightness should be suitable. If it is too tight, it will increase power consumption, and bearing is easy to wear; if it is too loose, the sprocket is easy to beat and fall off the chain.
The degree of tightness of the sprocket is: if lifted up or pressed down from the middle of the sprocket, the center distance between the two sprocket is about 2%-3%.

2. The sprocket shall be installed on shaft without swing and skew.
The end faces of the two sprockets in the same transmission assembly should be in the same plane. When the center distance of the sprocket is less than 0.5 meters, the deviation can be 1 mm;
When the center distance of the sprocket is more than 0.5 meters, the deviation can be 2 mm. But there shall be no friction on sprocket tooth side. Integral offset.
If the offset is too large, chain is prone to fall off and wear is likely to accelerate. When replacing the sprocket, be sure to check and adjust the offset

3. After the sprocket is severely worn, the new sprocket and the new chain should be replaced at the same time to ensure good meshing.
You cannot replace new sprockets separately. Otherwise, it will cause bad engagement and accelerate the wear of new sprockets.
If the tooth surface of the sprocket is worn to a certain degree, it should be turned over in time (the sprocket used with adjustable surface) to extend the life time.

4. If the new sprocket is too long or elongated after use, and difficult to adjust, you can remove the link, but the number of the links must be even.
The link should pass through the back of the sprocket with the lock piece being inserted outside, and the opening of the lock piece should be in the opposite direction of the turning.

5. Lubricating oil should be timely filled when sprockets are working. Lubricating oil must enter the matching clearance between the roller and the inner sleeve to improve working conditions and reduce wear.

6. The old sprocket cannot be mixed with part of the new sprocket, and should be replaced as a complete set, otherwise it is easy to produce impact in the transmission. Separate replacement of sprockets will increase wear.

Example of Use

Used for driving power A mechanism that can convert motor power into roller rotation by combining multiple sprockets and chains

Used for transporting workpieces A chain conveyor frame with high versatility using flat profiles and chain guides

Used for transporting workpieces A mechanism used to mount accessories on the chain, and extract and transport workpieces