Timing Pulleys Keyless/High Torque/S8M

Usually, timing pulleys and timing belts are widely used to design mechanisms for transmitting rotational power generated by motors.
Driving and transmission are realized through the engagement between the teeth of timing pulleys and timing belts.

The shaft bore may not have surface treatment.
Bushings are available in Standard Type (ST Bushing) and Short Type (SH Bushing). Refer to Detailed Specifications of Bushings

Part Number				Material			Surface Treatment
Belt Width 15mm	Belt Width 25mm	Belt Width 30mm	Belt Width 40mm	Pulley	Flange	Bushing	Pulley	Flange	Bushing
A: 17  W: 22	A: 28  W: 33	A: 33  W: 38	A: 44  W: 49
E-HTLA□□S8M150	E-HTLA□□S8M250	E-HTLA□□S8M300	E-HTLA□□S8M400	Aluminum Alloy 7A09	Aluminum Alloy	Equivalent to S45C	Clear Anodized		-
E-HTPL□□S8M150	E-HTPL□□S8M250	E-HTPL□□S8M300	E-HTPL□□S8M400	Equivalent to S45C	SPCC	Equivalent to S45C	Ferroferric Oxide Protective Film
E-HTLG□□S8M150	E-HTLG□□S8M250	E-HTLG□□S8M300	E-HTLG□□S8M400				Electroless Nickel Plating

Film hardness of hard clear anodize is 300HV~.
If there are requirements for rust prevention, give priority to products with surface treatment of electroless nickel plating on other pages.

Part Number			Pulley Shape	dH7 range (select Shaft Bore Dia. according to Table 1)								P.D.	O.D.	F	E
				S8M150		S8M250		S8M300		S8M400
Type	Number of Teeth	Type & Nominal Width		Shape E (ST Bushing)	Shape F (SH Bushing)	Shape E (ST Bushing)	Shape F (ST Bushing) (SH Bushing)	Shape E (ST Bushing)	Shape F (ST Bushing) (SH Bushing)	Shape E (ST Bushing)	Shape F (ST Bushing)
E-HTLA E-HTPL E-HTLG	18	S8M150 ＊A：17 ＊W：22 S8M250 ＊A：28 ＊W：33 S8M300 ＊A：33 ＊W：38 S8M400 ＊A：44 ＊W：49	E F	12	-	12	12	-	-	-	-	45.84	44.46	52	36
	19			12・14・15	12	12・14・15	12・14・15	15	15	-	-	48.38	47.01	55	40
	20			12~17	12	12~17	12・14・15	15・16・17	15	-	-	50.93	49.56	58
	21			12~17	12	12~17	12~17	15・16・17	15・16・17	16・17	16・17	53.48	52.1	61	45
	22			12~17	12	12~17	12~17	15・16・17	15・16・17	16・17	16・17	56.02	54.65
	24			12~17	12	12~17	12~17	15・16・17	15・16・17	16・17	16・17	61.12	59.74	67	50
	25			12~25	12	12~25	12~25	15~25	15~25	16~25	16~25	63.66	62.29	70	56
	26			14~25	-	14~25	14~25	15~25	15~25	16~25	16~25	66.21	64.84	74	58
	28			14~25		14~25	14~25	15~25	15~25	16~25	16~25	71.3	69.93	80	60
	30			14~32		14~32	14~32	15~32	15~32	16~32	16~32	76.39	75.02	87	67
	32			14~32		14~32	14~32	15~32	15~32	16~32	16~32	81.49	80.12
	34			16~35		16~35	16~35	16~35	16~35	16~35	16~35	86.58	85.21	95	75
	36			16~38		16~38	16~35	16~38	16~35	16~38	16~38	91.67	90.3	99	80
	38			16~42		16~42	16~35	16~42	16~35	16~42	16~42	96.77	95.39	104	84
	40			20~42		20~42	20~35	20~42	20~35	20~42	20~42	101.86	100.49	111	90
	44			20~42		20~42	20~35	20~42	20~35	20~42	20~42	112.05	110.67	119	100
	48			20~42		20~42	20~35	20~42	20~35	20~42	20~42	122.23	120.86	127	105
	50			20~50	-	20~50	20~35	20~50	20~35	20~50	20~42	127.32	125.95	135	115
	60			20~50		20~50	20~35	20~50	20~35	20~50	20~42	152.79	151.42	160	140

Select Shaft Bore Dia. according to Table 1

■Table 1: Shaft Bore Dia. Selection

dH7	Allowable max. torque N・m		D		(L)
	ST Bushing	SH Bushing	ST Bushing	SH Bushing
12	48	23	32	31	10.5
14	73	-	35	-	12
15	78		36
16	83		37		13
17	88		38
18	154		43		14
19	163		45
20	171		46
22	186		48
24	206		50
25	216		52
28	353		54		15.5
30	382		57
32	412	163	59	58	16.5
35	451	173	63	61
38	686	-	70	-	19
40	725		71
42	757		74		20
45	1490		84		24.5
48	1600		87
50	1660		89

Using a bushing with electroless nickel plated surface reduces maximum allowable torque and axial load by 20%-30%.

Features of MISUMI Keyless Timing Pulleys
Feature 1: Keyless timing pulleys require no keyway machining, and round shaft and round hole can be used directly.
    Urgent design changes can be made due to the reduction of cutting and machining time.


Feature 2: Keyless timing pulleys are connected with bolts only, allowing for easy installation and removal.
    Equipment maintenance can be easily carried out without using a special tool. Parts are reusable, effectively reducing the cost.


Feature 3: Keyless timing pulleys enable free alignment at any position during assembly.
    Alignment control is possible during assembly, thus eliminating the need to align the key and tooth in the design phase.


Feature 4: Keyless timing pulleys have no loosening. When a key is used, the keyway becomes loose, but there is no gap in the keyless bushing. It is therefore suitable for places where there are repeated forward and reverse rotations.
    Long-term high coaxiality connection can be achieved. Suitable for servo motors and other places where there are repeated forward and reverse rotations.

■Mounting method for keyless timing pulleys
①Wipe off the stains on the shaft surface and apply a layer of lubricant or grease. (Do not use any lubricant or grease that contains molybdenum abrasion inhibiting agent.)
②Also wipe the contact surface between the timing pulley and the bushing, and apply lubricant or grease. In addition, the fastening bolt thread surface and bearing surface must be applied lubricant or grease.
③Insert the timing pulley and bushing into the shaft after temporary assembly. (Do not tighten the bushing directly with the bolt without putting it through the shaft.)
④After positioning is completed, tighten the bolts gently (about 1/4 of the specified tightening torque) and diagonally in sequence with a torque wrench.
⑤Tighten with increased tightening torque (about 1/2 of the specified tightening torque).
⑥Tighten again to the specified tightening torque.
⑦Tighten the fastening bolt circumferentially in sequence.

■Disassembly method for keyless timing pulleys
①Work with the unit at a complete stop.
②Loose the fastening bolt circumferentially in sequence
③Insert the bolt into the threaded hole for disassembly and evenly screw it in.
④When reinstalling, repeat the steps in “Installation”.

① If there are requirements for rust prevention, give priority to products with surface treatment of electroless nickel plating on other pages.
  Please refer tosurface treatment and rust prevention methods
② When installing a keyless bushing, be sure to apply lubricant or grease to the shaft surface, the contact surface between the pulley and the bushing, and the fastening bolt.
  Otherwise it will not be securely tightened and may cause the shaft to idle.
③ Tighten the bolt after inserting the bushing into the shaft. (If the bolts is tightened before inserting the bushing, it will cause deformation of the bushing.)
④ Use a torque spanner to tighten the bolts.
⑤ Do not use bolts other than those supplied.

Technical Data of Toothed Timing Belts and Timing Pulleys
①Data on the selection of timing pulleys and timing toothed belts, tensioning force, etc. (drive).
②Data on the selection of timing pulleys and timing toothed belts, tensioning force, etc. (transmission & conveyance).
③Main causes and countermeasures for the damage, breakage, abnormal noise of toothed timing belts.
④Reference data on the replacement time of toothed timing belts.
⑤Data on dimensional tolerance of timing pulleys.