Hoerbiger-Origa is extending its BHD series of modular belt-driven linear actuators for heavy-duty applications with the addition of a smaller 20mm unit. Developed to offer the advantages of a sealed mechanism and fit-and-forget installation, the BHD units incorporate a precision recirculating ball bearing rail that gives them a load-carrying capacity of up to 2tonnes – making it suitable for very demanding of applications.
The decision to develop a heavy-duty BHD actuator was based on the observation that users increasingly have high-load requirements in tight space envelopes. Hoerbiger-Origa's development team retained the fundamental concept of its linear actuator range, developing a new compact low-profile device that is housed in a high-strength, one-piece aluminium extrusion. The early success of the original size 25, 32 and 50 versions prompted the launch of an extremely compact size 20 version to extend the series and cater for high-cycle and high-duty applications typically found on assembly lines and packaging machines.
The low profile is achieved by mounting the belt pulleys with their axes vertical rather than horizontal, so that the two runs of the belt loop are side-by-side instead of one above the other. The extruded housing is strong enough to be used as a structural machine element in many applications, absorbing any static loads present - including side and bending forces. Dynamic loads being moved by the actuator are carried entirely by the recirculating ball bearing rail for low-friction, highly dynamic performance.
Sealing and sensors
A stainless steel sliding seal is mounted in the housing to ensure that the belt mechanism is fully protected from ingress of dirt and loss of oil. Modular mounting options and dovetail slots for adding sensors and other ancillary equipment are also encompassed within the profile of the housing.
The belt is made from a high-performance polyurethane reinforced with stainless steel; it is supplied in 16, 20, 25 or 40mm widths, depending on the size of the BHD unit. The belt requires no maintenance or adjustment throughout its service life, which is measured in years for most applications.
BHD actuators can run at speeds of up to 5m/s, which is said to be fast enough for 95 per cent of all application requirements and probably more than adequate, considering the loads it is likely to be used with. Acceleration capabilities are up to 30m/s2, which is high enough that cycle times on short-stroke applications can be reduced.
Strokes up to 6m - or more
Stroke length is infinitely variable up to 6m; the decision to develop this long stroke capability was based Hoerbiger-Origa's experience in linear motion engineering, which suggests that large loads sometimes need to be transported considerable distances. Stroke lengths above 6m are also available to special order.
In keeping with the modular concept of the BHD range, various drive and motor control packages are available to suit the specific requirements of the users application (including stepper, servo and induction types). Further options include integral gearboxes, bi-parting carriages and inter-connection mountings for multi-axis applications.