Silent technology for traction drives

In order to realize an automatic conveyance device that requires quietness.

As the declining birthrate and aging population increases, the labor force is decreasing, and automatic conveyance devices that replace human labor to carry goods at the site of the logistics system are spreading. Unguided technology, which can be moved even without the need to follow a guide such as a tape, is evolving. In addition to factories and warehouses, the application of unguided automatic conveyance devices in other industries is also attracting attention. However, if it is used for luggage transportation for hotel guests, transportation of office materials and equipment, transportation of library collections, etc., there is a higher demand for the quieting of unguided automatic transportation devices for the sake of guests and users of these facilities. As a result, all the focus is on the traction drive with excellent silent performance.

The lubricant is cured and the power is transferred at high pressure

Only when the oil film passes through the contact points of the rollers does it cure under high pressure.

A traction drive is a technology that transmits power from one roll to another using rolls that are pressed against each other and rolled by a film of lubricating oil. The contact part of the roll will generate a very high pressure. Liquid molecules move freely at atmospheric pressure, but at high pressure, they are regularly aligned into solid crystals. Traction drives take advantage of this property to transfer power from one roll to another. Unlike gear drives, the gears are meshed without impact noise, so they are quiet, and they are always in contact with each other even when they are not rotating, so that backlash is small.

There are no high-frequency speed changes due to pitch errors (machining accuracy) of gears, and power can be transmitted very smoothly.

Since 1952, Japan Denko Shinbo has been mass-producing industrial transmissions equipped with traction drives, and has been widely used in many industrial equipment to date.

Comparison of gear transmission mechanism and traction drive. In addition to transmitting torque, traction drives have advantages

Miniaturization through various improvements

The disadvantage of traction drives is that the transmission torque that can be achieved by a specific size is lower than that of a gear reducer, so it has to be enlarged. In the past, in order to obtain the same torque, it was sometimes necessary to increase the size by 4 to 5 times the original size, depending on the specifications.

The disadvantage of traction drives is that the transmission torque that can be achieved by a specific size is lower than that of a gear reducer, so it has to be enlarged. In the past, in order to obtain the same torque, it was sometimes necessary to increase the size by 4 to 5 times the original size, depending on the specifications. Japan Densho Shinho has been working on the miniaturization of traction drives. In principle, the greater the pressing force applied between the rollers, the greater the transmitted torque. However, if the roller is pressed with a lot of force, the pressure on the contact surface will become too high, and the life of the component itself will be shortened, so it is necessary to secure a certain size.

Therefore, by working on the shape of the roller, the contact area between the rollers is extended from the point to the line, so as to distribute the pressing force, and through such a design, the roller can withstand a greater pressing force. In addition, by computer simulation using FEM (Finite Element Method) analysis, the structure was optimized to achieve component strength that can withstand high pressures. Today, it has succeeded in achieving almost the same dimensions as gear reducers.

Compared to gear reducers, it has been succeeded in achieving a quieter temperature of 13 dB

In 2016, Japan Denco Shinho was the first company in the industry to develop the S-CART, an unmanned transport trolley that can be set at will. Although the transfer trolley uses a gear reducer for power transmission, it has been widely praised for its wide range of applications and can meet the loading needs of 100kg/200kg/500kg/1t. Recently, Japan Denco Shinho has also developed and designed a dedicated unmanned trolley for the hotel, which is equipped with a tracking function that can follow hotel staff and guests while carrying luggage, effectively assisting the hotel's luggage handling business. The hotel S-CART is equipped with a traction drive and plans to promote it in the hotel industry to expand sales.

The S-CART for hotels was made for exhibition demonstrations. This is an autonomous mobile robot called AMR (Autonomous Mobile Robot), which has recently become a hot topic. The robot can carry luggage instead of a baggage handler, and it also has the function of following hotel staff and guests and returning to a specific location.

In a noise comparison experiment using an unmanned guided trolley equipped with a gear reducer and a traction drive in the same housing, the noise level of the traction drive was as low as 13 dB. Even if you drive in a library, the noise emitted is almost imperceptible, so it has good marketability.

Noise is measured under the set conditions of no load, driving range of 6 m, and maximum speed of 3.6 km/h. It can be seen that the noise measured by the gear transmission mechanism is 65.7 dB, and the noise measured by the traction drive is 55.4 dB, which is a large difference.

The product passed the company's in-house durability test in 2020 and is currently in the final commissioning phase in preparation for mass production. In addition, considering that miniaturization and quietness of products are endless challenges, the goal in the future is to realize a traction drive that is smaller than a gear reducer and quieter than a motor.

Silent technology for traction drives

Sections viewed

Contact

working hours