Timing belt CXP 738 3M - CONTI® SYNCHROFORCE

Timing belt CXP 738 3M - CONTI® SYNCHROFORCE

Timing belt CXP 738 3M - CONTI® SYNCHROFORCE is an endless rubber timing belt for synchronous power transmission in industrial belt drives. The profile is HTD 3M CXP, the length is 738 mm, and the belt has 246 teeth. The teeth work in mesh with the timing belt pulley and maintain a fixed movement between the shafts.

Product data

• Effective length: 738 mm
• Number of teeth: 246
• Tooth profile: HTD 3M CXP
• Tooth pitch: 3 mm
• Profile type: HTD 3M in CXP version
• Tooth height: 1.2 mm
• Belt height: 2.4 mm
• Standard widths: 6 mm, 9 mm and 15 mm
• Length tolerance: ±0.30 mm
• Material: Chloroprene rubber
• Reinforcement: Fiberglass reinforcement
• Tooth surface: Prepared polyamide tissue on the tooth side
• Series: CONTI® SYNCHROFORCE CXP

Construction and materials

The technical structure consists of an elastic rubber matrix with fiberglass reinforcement and a tooth surface with polyamide fabric. The structure is made for dynamic belt drives, where repeated bending and high speeds continuously load the belt. The spine and teeth are made of chloroprene-based rubber, while the fiberglass reinforcement is located as the load-bearing reinforcement in the belt. This results in a belt that can absorb tensile forces and still maintain the synchronous function, while the rubber part can bend around the timing belt pulleys during repeated rotations.

The polyamide fabric on the teeth is an important part of the belt's wear surface. It lies between the tooth rubber and the profile of the timing belt pulley and contributes to lower friction, smoother engagement and better protection of the tooth surface. In a CXP belt, the material layers are not separate functions, but parts of an overall construction where flexibility, tensile strength and tooth stability must work simultaneously.

Profile and tooth engagement

CXP 3M uses a metric tooth pitch of 3 mm. The HTD tooth shape has a semi-circular profile, which provides a large and stable engagement surface between the belt and the timing belt pulley. This shape is known for its high safety against tooth skipping, because the tooth can engage deeply and smoothly into the profile of the timing belt pulley. For this belt, the 738 mm effective length means that the belt has 246 teeth distributed around the endless belt.

Fine tooth pitch makes the profile suitable for small timing belt pulleys and precise movements where the belt must run smoothly at high rotational speeds. The profile is also part of the CXP series, where ContiTech has combined tooth shape, reinforcement and rubber compound for operation under demanding loads. The technical length tolerance for this length class is ±0.30 mm. The tolerance covers the manufacturer's effective length and pulleybase deviation.

Operating characteristics

CONTI® SYNCHROFORCE CXP is designed for high belt speeds and high dynamic loads and can be used at belt speeds of up to 50 m/s. The high load capacity is due, among other things, to the specially developed reinforcement and the strong material bond between rubber, reinforcement and tooth surface. This gives the belt high residual tensile strength and improved resistance to tooth shearing under heavy loads.

The belt transmits motion synchronously, so that the driving and driven shafts maintain a fixed speed ratio. It works without lubrication and is designed for maintenance-free operation. The optimized profile matching between the timing belt and timing belt pulley, together with the polyamide fabric on the tooth side, contributes to quiet operation. In demanding operation, this is an important property, because both tooth engagement and load variation can affect the sound level and stability.

Resistance to operating environment

The CXP version is temperature resistant from -20 °C to +100 °C depending on the application. The belt is ozone resistant, suitable for tropical climates, conditionally/moderately oil resistant and electrically conductive according to ISO 9563. These properties make the belt suitable for industrial environments where temperature, air, oily influences and static electricity can affect operation.

The rubber-based construction also provides some damping in the drive. The timing belt can therefore be used in solutions where a quieter and lighter transmission is desired than chain or sprocket drives. The function of the belt still depends on the mechanical structure around it, but the CXP construction itself is made to maintain strength and flexibility under repeated loads.

Application

The endless construction makes the belt suitable for continuous operation because there is no welding or joining in the belt. This contributes to uniform strength all the way around the belt. Compact synchronous drives, instrumentation, lightweight machine structures and other installations with limited space around the timing belt pulleys. It can be used in industrial plants where synchronous operation, high efficiency and stable power transmission without lubrication are required. The CXP series is particularly relevant in fast-running drives where a standard timing belt does not provide the same load reserve.

The effective length of 738 mm and the CXP 3M profile make this belt a specific dimension in the series. The belt fits into timing belt pulleys with a corresponding tooth pitch and tooth shape. When timing belt pulleys and belt have the same tooth profile, the load is distributed over the teeth that work in mesh and the movement is transmitted without the slip known from friction-based belt types.

Installation and ongoing operation

In a synchronous belt drive, belt tension, the condition of the timing belt pulleys and the parallelism of the shafts are important for the life of the belt. A CXP belt works best when the tooth surfaces can move cleanly in and out of the profile of the timing belt pulleys. Too low a tension can cause unstable tooth engagement, while unnecessarily high tension can increase the load on bearings, shafts and reinforcement. A correctly constructed transmission utilizes the strength of the belt without overloading its materials.

The belt is endless without joints. This provides a uniform structure all the way around and is an advantage in dynamic operation because the belt does not have a weaker joint pu . The same construction makes the belt suitable for repeated accelerations, uniform rotational speed and operation with continuous tooth engagement.

Question about the belt

Can CXP run without lubrication?

Yes. SYNCHROFORCE CXP is a timing belt for dry, synchronous power transmission and does not require lubrication. This distinguishes it from chain drives, where lubrication is typically part of the operation.

What does an HTD tooth shape mean?

HTD stands for High Torque Drive. The semi-circular tooth shape provides good protection against tooth skipping and is suitable for power transmission with high torque.

What does tooth division mean?

The tooth pitch is the center-to-center distance between two adjacent teeth measured along the belt's pitch line. A 3M belt has a 3 mm tooth pitch.

What does CXP mean on this timing belt?

CXP is ContiTech's reinforced version for belt drives with high belt speeds and high dynamic loads. The series is designed for the synchronous transmission of power and motion in industrial drives.

What does the fiberglass reinforcement in the belt do?

The fiberglass reinforcement acts as reinforcement and helps the belt maintain its length under load. This is important in synchronous belt drives, where tooth position and the effective length of the belt have a direct impact on operation.

The rubber matrix of the belt provides cushioning and flexibility, while the fiberglass reinforcement absorbs the tensile load. The timing fabric on the inside is the part of the belt that works directly against the timing belt pulley. In practice, these parts must work together: the rubber must be able to bend around the timing belt pulleys, the reinforcement must limit length change, and the tooth surface must resist wear from repeated engagement.

The CXP design is particularly relevant when the belt is to operate at high belt speeds. The CXP series can operate at belt speeds of up to 50 m/s and is therefore one of the reinforced timing belts for dynamic drives. This does not mean that all belt drives can automatically operate at this speed; the actual operation depends on the timing belt pulleys, center distance, load, width, shaft alignment and the machine structure. However, the belt type itself has been developed with materials and tooth structure that are suitable for this type of load.

Compared to a conventional friction belt, the timing belt provides a direct, positive-locking transmission. This means that the belt does not have to pull on the timing belt pulley to transmit the movement. The profile of the teeth does the work, and this reduces the need for high pretension. In many machine designs, this can provide a more compact and quiet solution.

The dimensions of the profile affect how the belt bends and how the tooth carries the load in the timing belt pulley. For 3M, the tooth pitch is 3 mm, the tooth height is 1.2 mm, and the total belt height is 2.4 mm. These measurements describe the profile itself and are not the same as the belt width, which depends on the individual belt variant.

The technical length tolerance for this length class is ±0.30 mm. The tolerance describes the manufacturer's level of precision for the belt's effective length and is used when assessing the center distance and belt tension in a synchronous drive. A timing belt of this type is therefore not only defined by its name and profile, but also by the exact length class and the tolerances associated with it.