[New Product] Unit Products for Office Equipment - NTN

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Unit Products for Office Equipment Larger diametersection Torque adjustment section Inner ring Coil spring Smaller diameter section Torque generation section Inner ring Coil spring Projection Projection Cutout on inner ring Cutout on inner ring Cap Outer resin component Cap Outer resin component Old design (NTS18) Ultra-compact type (NTB14) Fig. 1 Structure of current type (NTS18) and new type (NTB14) section functions as a torque generation section, and the larger diameter section serves as a torque adjustment section. To set the torque, the lid is turned relative to the outer resin component to twist the larger diameter section, and the resultant constricting force causes the smaller diameter section of the coil spring to shrink to restrain the inner ring. On the old design, the end hooks of the coil spring are engaged with the outer resin component and the lid. Thus, the inner ring of the old design can rotate only in the torque generation direction. The newly developed ultra-compact torque limiter unit (hereafter referred to as NTB14) does not have the large diameter section that is the torque adjustment section of the coil spring in the old design. Instead, the tightening allowance between the spring bore and the inner ring outer surface is responsible for control of the torque generated. As a result, the outer diameter and the length of the outer resin component on the NTB14 design are reduced. In addition, this novel structure has enabled the torque limiter to be capable of rotation in both directions. 1.3 Advantages of NTB14 1.3.1 Compact design Old design (NTS18): 18 OD x 18 L (mm) New design (NTB14): 14 OD x 12 L (mm) Benefits of use The torque limiter can be incorporated into the rubber rollers on the paper feeder section, so the sizes of the rubber rollers can be reduced in both diameter and length (Fig. 2). In addition, the number of parts associated with the rubber rollers may be decreased and the assembly procedure for the rubber rollers can be simplified. NTB14 Fig. 2 Example of torque limiter and rubber roller all- inone design Benefits of use Removal of jammed paper is easy. Rubber rollers Paper stock 1.3.3 Prevention of chemical attack Like the old design, the new torque limiter has an inner ring made of an oilless sintered metal, in which the oil in the sintered metal does not pose risk of chemical attack to the resin components. Benefits of use • The new torque limiter does not pose problems to adjacent resin materials. • Since the inner ring is made of an oilless sintered metal, there is no possibility of leaking lubricating oil, and no relubrication is necessary. 1.4 Durability A typical result of a durability test is shown in Fig. 3. The loss in torque with the new design is roughly equivalent to that with the old design. In other words, the durability of the new design is comparable to that of the old design. 1.3.2 Capability of rotation in both directions The new design is capable of rotation in both directions. -69-
NTN TECHNICAL REVIEW No.742006 Torque mNm 40 35 30 25 20 15 10 5 Test conditions Operation cycle: 1.1 sec. on, 0.2 sec. off Operation period: 300 hrs. Running speed: 220 min -1 0 0 50 100 150 200 250 300 1.5 Standard shape and materials used and torque setting The standard shape of the NTB14 is illustrated in Fig. 4, and the materials used are listed in Table 1. Note NTN will supply non-standard shaped variants upon request. Allowable torque setting rage: 24.5–39.2 mN-m {250–400 gf-cm} 2-2.5 9 6 Time h Fig. 3 Results of endurance test 1 2 3 4 14 Old design NTB14 2-3.2 2. Introduction of the TDL16 Compact, Lightweight Torque Diode 2.1 Overview To realize full-color capability, photocopying machines and printers are incorporating increasing numbers of components and movable parts. However, the floor space requirements of this equipment need to be roughly the same as with conventional monochromatic machines. Therefore, the need for more compact components is great. At the same time, demands are mounting for compliance with energy conservation and environmental regulations, as well as for satisfaction of requirements to acquire Blue Angel Mark certification. For these reasons, photocopying machine and printer manufacturers are making efforts to decrease power consumption for this type of equipment. The lock-type torque diode can hold the drives for trays and other components in position with its reverse-input prevention function even when the equipment is powered off. For this reason, this type of torque diode is advantageous for saving energy compared to arrangements in which the drive is held in position by supplying power to the motor. NTN has developed and continues to provide the TDL28 lock-type torque diode for office automation equipment. However, since its components are made of steel, it is heavy and structural limitations make development of a compact variant of this torque diode difficult. To address this challenge, NTN has developed the TDL16, a new torque diode that features both compact size and light weight. 2-2.5 12 12.4 3.9 Fig. 4 Design of NTB14 Table 1 Composition and material of NTB14 Code Component description Outer resin 1 component 2 Lid 3 Coil spring 4 Inner ring Lubricant Material used Polyacetal resin (hue: black) Polyacetal resin (hue: white) Spring steel Iron-based sintered material Chemical attack-free oil (impregnated into the inner ring) Photo. 2 New type Torque Diode -70-
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[New Product] Unit Products for Office Equipment - NTN

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