Timing belt 1320 HTD 8M

HTD timing belt 8M 1320 - Optibelt® Omega™ rubber timing belt

Optibelt® Omega™ HTD 8M 1320 rubber timing belt is an endless rubber timing belt for mechanical drives where position, speed and power must be transferred without slip between the belt and pulley. The rounded teeth of the HTD profile provide a stable engagement in the associated profile pulleys. The product belongs to the type of belts used in mechanical systems where the teeth carry the movement through positive engagement rather than pure friction. The product has an effective length of 1320 mm, 165 teeth and tooth profile HTD 8M. The belt has teeth on the inside and works in pulleys with a corresponding HTD profile.

Product data

• Effective length: 1320 mm
• Number of teeth: 165
• Tooth profile: HTD 8M
• Tooth pitch: 8 mm
• Material: chloroprene rubber
• Reinforcement: fiberglass cord
• Tooth surface: nylon fabric
• Construction: endless rubber timing belt
• Thickness: 5.4mm
• Color: black
• Widths from 10 to 120 mm

The single-sided design is suitable for classic two- or multi-pulley drives, where the belt's inner teeth provide the synchronous power transmission. The tooth pitch of 8 mm means that the distance between two tooth centers follows the metric HTD standard for this profile. The length of 1320 mm and the number of teeth of 165 provide a fixed rotation, where the belt can be used in synchronous drives with the same profile and tooth pitch.

Construction and materials

In terms of material, the belt combines a rubber-based body with high tensile strength in the cord layer and a protected tooth area. The dimensionally stable construction is important in synchronous operation, because the belt must be able to withstand tensile forces without noticeably elongating. At the same time, the teeth must be able to work repeatedly in the pulley grooves without unnecessary wear.

Chloroprene rubber is used in this type of timing belt because the material combines flexibility, strength and abrasion resistance in common machine environments. The fiberglass cords act as the tensile load-bearing element of the belt and help limit elongation over time. The nylon weave on the teeth protects the contact surface where the teeth meet the pulley grooves and is an important part of the belt's ability to operate smoothly through repeated engagements.

HTD profile and synchronous function

The HTD profile has rounded teeth, which distribute the load differently than trapezoidal tooth profiles. With correct engagement, the force is located in the tooth flanks, and the belt can transmit motion with a fixed ratio between the rotation of the pulley and the revolution of the belt. The tooth pitch indicates the distance between two tooth centers measured along the pitch line of the belt, and the effective length indicates the circumference of the belt along the same theoretical line.

For HTB/HTD 8M, the reference geometry is specified with 8.00 mm tooth pitch and 3.38 mm tooth height. The product-specific thickness/height is stated in the product data. The profile reference geometry supplements the specific product data for the belt, where the specified thickness and width are stated in the product data. The practical function is that the belt can transmit motion with low slip, high efficiency and a stable relationship between driving and driven pulleys.

Operating characteristics

The belt is suitable for drives where high efficiency and low noise levels are desired. When the timing belt and pulley work together correctly, the drive can withstand normal starting and operating loads without losing synchronization. The low maintenance is a practical advantage in machines where the belt drive is part of daily operation.

The technical data for HTB/HTD describes this belt class as suitable for synchronous transmission, high and constant angular speeds, high efficiency, resistance to peak loads, low noise level, lubrication-free operation and low maintenance requirements. For the standard type, a linear belt speed of up to 30 m/s is specified. These properties are suitable for a timing belt drive where operational reliability and a purely mechanical solution are part of the design.

Areas of application

The belt type is used in many forms of mechanical engineering, including packaging equipment, light conveyors, machine tools, woodworking, HVAC solutions, food mixers, refrigeration systems and other belt drives requiring synchronous motion. It is particularly relevant where chains or sprockets would cause more noise, higher weight or require lubrication.

The belt can be used in both continuous and periodic machine movements, where a belt drive must transmit power without lubrication and without metal-to-metal contact. Compared to chain drives, a rubber timing belt often provides a quieter solution, lower weight and a cleaner drive. Compared to friction belts, the tooth meshing provides a more precise relationship between the movement of the shafts.

Environment, temperature and chemical resistance

Environmentally, a standard rubber timing belt must be assessed based on the influences that exist around the drive. The technical data for the HTB/HTD type indicates medium resistance to water and environmental influences, low resistance to mineral oil and oil, and medium resistance to grease. Resistance to acids, bases, solvents and fuels is not stated as suitable for the standard design. This means that the belt primarily belongs in ordinary mechanical operating environments where it is not exposed to continuous chemical influence.

The technical basis specifies a temperature range of -25 °C to +80 °C for the HTB/HTD standard type with short-term peak loads of up to +100 °C. Temperature, speed, belt tension and environmental influences are interrelated in the practical service life. In stable operation without abnormal heat, misalignment or contamination, the belt materials can work with a uniform tooth mesh over many operating times.

Installation and maintenance in operation

Belt life depends on load, alignment, belt tension, pulley condition and the surrounding environment. Worn profile pulleys can negatively affect new belts because the tooth engagement no longer follows the original geometry. A clean, properly aligned drive with adequate tension provides the best conditions for stable operation.

A timing belt should not be bent sharply against the intended direction of bending or pressed over a pulley in a way that damages the cord or teeth. Pulleys with the correct profile, clean tooth grooves and good shaft alignment provide the best engagement. During operation, smooth running, uniform sound and absence of edge wear are signs that the belt and pulley are working harmoniously together.

Questions about product features

Why are round HTD teeth used?

The round tooth shape provides a stable and relatively soft engagement with the profile pulley. This can reduce noise and provide a more even load distribution in the belt drive.

What does effective length mean?

The effective length is the pitch length of the belt measured along the theoretical pitch line of the belt. It is used to identify the circumference of the belt in a synchronous drive.

Does the belt require lubrication?

No, a rubber timing belt in HTD profile is designed for lubrication-free operation. The power is transmitted through the tooth engagement and not via a lubricated chain.

What affects lifespan?

The service life is particularly affected by correct tension, alignment, condition of the pulleys, load, temperature and environmental influences around the drive.

HTD 8M is a widely used profile for industrial belt drives where more power must be transmitted than in the smaller metric profiles. The 8 mm tooth pitch provides larger teeth and a more robust contact with the pulley. The profile is suitable for many common machine drives where operational reliability, available widths and a stable engagement are important factors.

The black rubber surface and protected tooth area make the belt practical in general industrial environments. However, the belt should be seen as part of an overall drive, where pulleys, tension, shaft alignment and load together determine the actual operation. A correctly constructed timing belt transmission provides quiet operation, limited noise and a pure mechanical solution without lubricant.

In continuous operation, heat generation, tooth engagement and belt tension are key factors. Too tight an operation can increase the load on bearings and cords, while too loose an operation can make the tooth engagement less stable. The round HTD geometry, nylon weave and cord reinforcement work together to keep the movement stable when the belt is used within the normal operating conditions of the profile.

The function of the belt is based on a simple mechanical idea: each tooth has a specific location, and the profile of the pulley determines how this location is translated into rotation. Therefore, the timing belt is suitable for systems where the relationship between the shafts must not change under load. The combination of rubber, cord and timing fabric also provides a more damped operation than many rigid transmission solutions.

The fixed relationship between the number of teeth, pitch length and tooth pitch makes the belt suitable for drives where the movement must be repeated the same from revolution to revolution. When the belt runs in suitable pulleys, several teeth work simultaneously in mesh, and the load is distributed over the part of the belt that is in contact with the pulley. This is an important difference compared to belt types where the power transmission depends on friction alone.