Double timing belt RPP5 DD 935

Megadyne MEGASYNC 935 RPP 5M DD double-timing rubber timing belt

Important product details

• Effective length: 935 mm
• Number of teeth: 187
• Tooth profile: RPP 5M DD
• Tooth pitch: 5.0 mm
• Design: Double-timing
• Material: Rubber
• Traction body: Fiberglass
• Tooth coating: Nylon fabric
• Tooth height: 2.00 mm
• Belt height: 5.20 mm
• Standard widths: 9 mm, 15 mm and 25 mm
• Brand: Megadyne MEGASYNC

Megadyne MEGASYNC 935 RPP 5M DD double-timing rubber timing belt is an endless rubber timing belt from Megadyne's MEGASYNC series. The product has a pitch length of 935 mm, 187 teeth, RPP 5M DD profile and standard widths of 9mm, 15mm and 25mm. The belt is designed for synchronous power transmission, where the belt's teeth engage positively in the profile of the pulley and keep the movement of the shafts in a fixed relationship. The belt is manufactured for synchronous drives, where the movement must be transferred precisely between pulleys without slipping. The fixed tooth pitch and the endless structure provide a uniform rotation, while the RPP profile contributes to lower noise and better engagement in the profile pulleys.

Product data and profile

The stated length of 935 mm is the belt's pitch length, i.e. the length measured along the theoretical pitch line in the tension layer. RPP 5M DD has a tooth pitch of 5.0 mm, and this variant has 187 teeth. The profile is a double-timing RPP profile with a 5 mm tooth pitch, and the overall design is intended for compact drives where teeth on both sides are used for power transmission or control in the same belt drive. The tooth height of the profile is 2.00 mm, while the nominal belt height for this design is 5.20 mm. The widths in this item follow the registered standard widths for the product: 9mm, 15mm and 25mm. With this length, the belt fits many common industrial belt drives, where there is a balanced distance between the belt pulleys and space for a stable enclosure. With 187 teeth, the belt has a longer tooth course, which is suitable for belt drives where several teeth can be in engagement over a larger part of the enclosure.

Construction and materials

The MEGASYNC RPP belt is built around a rubber body with high fatigue resistance, good resistance to heat and environmental influences and wear resistance in daily operation. The traction member is fiberglass, which is embedded in the belt and is selected for high tensile strength, stable length and good adhesion to the rubber body. The tooth side is covered with nylon fabric. The nylon fabric acts as a durable contact surface against the pulley and is treated to reduce friction in the engagement. The combination of rubber, fiberglass and nylon results in a belt that can operate smoothly in synchronous drives without continuous lubrication.

The double-timing DD design has teeth on both sides of the belt. This makes the belt suitable for constructions where the belt not only works against pulleys on the inside, but can also be part of a belt guide with external tooth engagement. This construction is typically used when several shafts need to be synchronized in the same belt drive, or when a compact belt guide requires that the force can be transferred from both sides of the belt. The DD design does not change the principle behind the RPP profile: the tooth shape is still parabolic, and the aim is still smooth engagement, lower noise and good resistance to tooth skipping. On a double-timing belt, the total belt height is greater than on a corresponding single-timing version, because there is a tooth profile on both sides of the belt. The belt is endless without a joint in the traction layer, which gives a uniform construction all the way around. This is important in rotating drives, where the same area of ​​the belt repeatedly passes in and out of the tooth grooves of the pulleys. The uniform construction helps maintain smooth running, fixed tooth pitch and stable load distribution during operation.

RPP tooth shape and tooth engagement

The RPP profile is developed as a parabolic tooth shape with a progressive pressure angle from the tooth root up to the tooth tip. This design gives a taller tooth at the same pitch length and reduces interference between the belt and pulley, especially when the drive is subjected to torque peaks. The tooth shape improves resistance to tooth skipping and tooth cutting, while also being able to transmit higher torque with less preload than older or simpler tooth profiles. There is a groove on the tooth tip, which makes the engagement more elastic. The groove helps the tooth to settle more evenly in the pulley groove and distributes the load more evenly between the teeth working simultaneously.

The RPP5 profile is a technical intermediate step between the very small and the larger RPP profiles. It offers more load capacity than the RPP3, but can still be used in relatively compact drives. Megadyne's RPP profile is designed to work in existing deep profile pulleys according to ISO 13050. This provides a high degree of compatibility in drives where the profile pulleys already follow this type of geometry. The positive tooth contact makes the belt suitable for precise synchronization, because the speed follows the number of teeth of the pulleys and does not depend on friction alone. In correctly dimensioned drives, MEGASYNC rubber timing belts can work at linear speeds of up to 30 m/s, making the series useful in both slower power transmission and faster machine movements.

Operating characteristics

The technical strength of the RPP 5M DD lies in the combination of precise tooth pitch, low noise level and high efficiency. The belt operates without the need for external lubrication, and the treated nylon surface of the teeth contributes to a lower level of friction in the contact zone. This makes the belt drive cleaner than chain drives and at the same time reduces maintenance. The synchronous movement means that the drive can maintain a constant angular velocity between the shafts when the pulley and belt are correctly designed as a system. The RPP tooth shape also helps to handle load peaks because the tooth engagement occurs gradually and not as a hard edge engagement.

The design is suitable for both continuous rotation and repeated start/stop movements, provided that the belt drive is dimensioned according to load, speed and pulley geometry. Drives with multiple pulleys, counter-engagement or compact layouts are typical examples of operation where the smooth engagement and good resistance to tooth skipping of the RPP profile are of practical importance. The standard version of the belt has medium resistance to water, grease and common environmental influences, low resistance to oil and mineral oil and no real resistance to acids, bases, solvents or fuels. The normal temperature range is -25 °C to +80 °C, with short-term peak loads up to +100 °C. The hardness of standard RPP belts is 74 ±4 ShA.

Installation and maintenance

An RPP timing belt works best when the pulleys, center distance and belt tension match the load in the drive. Too low a belt tension can lead to the risk of tooth skipping during torque peaks, while too high a tension can increase noise, heat generation and load on bearings. The ability of the RPP profile to work with lower preload is an advantage because it can reduce mechanical stress in the drive. The condition of the pulleys also has an impact on the service life. Worn or rough tooth grooves can increase friction and wear the nylon fabric faster, while correct alignment between the shafts provides a more uniform load across the width of the belt. The endless construction usually does not require any post-treatment of the belt itself during operation.

Technical questions about RPP 5M DD

What operating environments is RPP rubber suitable for?

The standard version has medium resistance to water, grease and general environmental influences and low resistance to mineral oil and grease. It is not intended as a chemical resistant belt against acids, bases, solvents or fuels. The temperature range is from -25 °C to +80 °C with short-term peak loads up to +100 °C.

Why are endless timing belts used?

An endless timing belt has no joints in the tension layer. This provides a uniform structure all the way around, which is an advantage in rotary drives where the belt constantly passes the pulleys under load. The fixed pitch length also makes the belt suitable for precise synchronous movements.

What does pitch length mean?

The pitch length is the length of the belt measured along the theoretical pitch line in the tension layer. For an RPP belt, this length is the key identification along with the pitch, number of teeth and width. When the length is given in millimeters, the number of teeth corresponds to the length divided by the pitch.

What does the RPP profile mean?

The RPP profile is a parabolic tooth shape with a progressive pressure angle from the tooth root to the tooth tip. This shape gives a taller tooth at the same tooth pitch and a more controlled engagement in the pulley. In practice, this means that the belt can transmit torque with lower noise and better resistance to tooth skipping than a simpler tooth shape in the same type of application.

Overall rating of the product

The Megadyne MEGASYNC 935 RPP 5M DD double-timing rubber timing belt combines the key features of a modern RPP rubber timing belt: endless construction, fiberglass pull, nylon weave on the teeth, parabolic profile and synchronous power transmission without lubrication. The product's length of 935 mm and 187 teeth make it a specific variant in the MEGASYNC program, while the RPP 5M DD profile indicates the tooth pitch and profile geometry. Overall, the combination of rubber body, fiberglass pull, nylon weave and RPP tooth shape results in a technical belt that is designed for precise, quiet and maintenance-friendly operation.