Timing belt CXP 3500 14M - CONTI® SYNCHROFORCE

Timing belt CXP 3500 14M - CONTI® SYNCHROFORCE

Timing belt CXP 3500 14M - CONTI® SYNCHROFORCE is a technical rubber timing belt in the CONTI® SYNCHROFORCE CXP version. The belt has an HTD 14M CXP profile, an effective length of 3500 mm and 250 teeth. It is used in timing belt drives where power and movement must be transmitted precisely via tooth meshing.

Product data

• Effective length: 3500 mm
• Number of teeth: 250
• Tooth profile: HTD 14M CXP
• Tooth pitch: 14 mm
• Profile type: HTD 14M in CXP version
• Tooth height: 6.1 mm
• Belt height: 10.0 mm
• Standard widths: 40 mm, 55 mm, 85 mm, 115 mm and 170 mm
• Material: Chloroprene rubber
• Reinforcement: Fiberglass reinforcement
• Tooth surface: Prepared polyamide tissue on the tooth side
• Series: CONTI® SYNCHROFORCE CXP

Construction and materials

The construction is built as a composite product, where the back, teeth, reinforcement and tooth tissue work together as one unit. The CXP design is based on chloroprene, fiberglass reinforcement as reinforcement and a prepared polyamide tissue on the tooth side. The back 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 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 14M uses a metric tooth pitch of 14 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 3500 mm effective length means that the belt has 250 teeth distributed around the endless belt.

The large tooth pitch and high tooth profile provide a robust tooth engagement surface for powerful belt drives with high torque. 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 0.05 mm per 500 mm length increase above 2250 mm, the manufacturer's tolerance for 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. Heavy synchronous drives, larger machines, main drives and industrial systems where the belt must transmit high power over larger timing belt pulleys. 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 3500 mm and the CXP 14M 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 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 14M belt has a tooth pitch of 14 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.

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.

Backflex and the use of a tension roller can be included in certain CXP designs when the belt drive is dimensioned for it. The flexibility of the belt and rubber-based construction make it suitable for dynamic grooves, but the bend radius, roller size and belt tension always have an impact on the load in the reinforcement and the tooth root.

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 technical length tolerance for this length class is 0.05 mm per 500 mm length increase above 2250 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 that apply to it.