Timing belt CXP 640 8M - CONTI® SYNCHROFORCE

Timing belt CXP 640 8M - CONTI® SYNCHROFORCE

Timing belt CXP 640 8M - CONTI® SYNCHROFORCE is a reinforced rubber timing belt from the CONTI® SYNCHROFORCE CXP series. The belt has an HTD 8M CXP profile, an effective length of 640 mm and 80 teeth. It transmits power through the tooth engagement between the belt and the timing pulley, so that the movement remains synchronous without slippage.

Product data

• Effective length: 640 mm
• Number of teeth: 80
• Tooth profile: HTD 8M CXP
• Tooth pitch: 8 mm
• Profile type: HTD 8M in CXP version
• Tooth height: 3.4 mm
• Belt height: 5.6 mm
• Standard widths: 20 mm, 30 mm, 50 mm and 85 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 8M uses a metric tooth pitch of 8 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 640 mm effective length means that the belt has 80 teeth distributed around the endless belt.

The semi-circular tooth shape provides a large engagement surface in the timing belt pulley and is suitable for power transmission with good safety against tooth skipping. 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

In a belt drive with correctly aligned timing belt pulleys, the movement is transmitted through the tooth engagement rather than friction. This provides a solid mechanical connection between the belt teeth and the profile of the timing pulley. Higher power machines, shaft drives, production equipment, conveyor systems and other belt drives where load and speed work together. It can be used in industrial systems 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 640 mm and the CXP 8M 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

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. An 8M belt has a tooth pitch of 8 mm.

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.

Why is polyamide tissue on teeth important?

The polyamide fabric protects the tooth surface, reduces friction in the engagement and contributes to smoother operation between the belt and the timing belt pulley. This is especially relevant at higher speeds and repetitive loads.

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.

The CXP series is designed for maintenance-free operation. This means that the belt itself does not require lubrication, and that the design is made to maintain stable function without the continuous lubrication often associated with chain drives. However, maintenance-free does not mean that the belt drive is independent of mechanical quality. Clean timing belt pulleys, correct tension and a stable shaft structure continue to be important for service life and smooth operation.

The electrical conductivity level according to ISO 9563 is a relevant property in many industrial environments where static charging should be limited. Together with ozone resistance, tropical resistance and conditional oil resistance, this results in a belt that is more robust to ambient conditions than a simpler standard timing belt. The temperature range for the CXP version is -20 °C to +100 °C, depending on the application.

The standard widths for this profile are 20 mm, 30 mm, 50 mm and 85 mm. The different widths allow the same length and tooth pitch to be used in belt drives with different power loads. A wider belt can distribute the load over a larger tooth surface, while a narrower belt can be an advantage where space and rotating mass must be kept to a minimum.

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 dimensions of the profile affect how the belt bends and how the tooth carries the load in the timing belt pulley. For 8M, the tooth pitch is 8 mm, the tooth height is 3.4 mm, and the total belt height is 5.6 mm. These measurements describe the profile itself and are not the same as the belt width, which depends on the individual belt variant.