Page 6 of catalogue Precision rail guides of SKF Linearsysteme GmbH

Increased performance achievable without design modification The Modular System is based on the well-proven LWR design which covers a wide range of applications. The new optimised LWRE series offers either doubled stiffness and a load carrying capacity increased by a factor of five or, alternatively, for a given load carrying capacity, a 50 % reduction in bearing size compared with the standard LWR design (Fig. 3).
Fig. 3

LWR 12

LWRE 6

Complete range In order to further simplify the application of Modular Range rail guides, all guides within a given size range have the same external dimensions and thus fit the space requirements of most commercially available rail guides. This results in a very wide choice in terms of load carrying capacity, stiffness and operating characteristics. From the economical point of view, the use of the optimised LWRE series offers a double advantage. Firstly (although the initial cost is slightly higher) the range of application is extended significantly as regards stiffness and load carrying ca6

pacity. It thus offers a far better price/performance ratio. Secondly, the replacement of other rail guides, including those supplied by other manufacturers and already installed, can be carried out with ease and in a minimum of time. Above all, where the user needs to increase machine performance, a unit with a higher load rating can be fitted. In-situ replacement is made easier by the fact that no new attachment holes or fixing devices are required when using rail guides of the Modular Range. An additional advantage is the worldwide availability through distributors, simply by quoting the appropriate catalogue number. The internal design of the LWRE series ensures increased operational life through even distribution of load. This results from the optimisation of the cross-section which permits the use of larger rolling elements. The new design leads to a significant improvement in the roller/raceway contact performance. An important additional benefit is the introduction of a practically maintenance-free cage made of POM that matches the stringent demands for long operational life of the rolling elements and maintains its dimensional stability up to +80 °C. The individual rollers are well covered and the space between the rails is almost filled, thus providing good protection against contamination. A special characteristic of the LWAKE 3, 6 and 9 cages is that they consist of ‘snap-on’ elements and can be fitted together to the required length (Fig. 4). Conventional crossed roller cages have their rollers arranged alternately evenly spaced, so that only half the rollers in a preloaded guide are loadbearing while the remainder act as idlers. In the new LWRE cage these essentially unused rollers can be partially turned in the direction of the load. For this purpose each individual cage segment is designed to

Fig. 4
Standard crossed roller configuration

Optional configurations of LWAKE 3, 6, and 9 cage segments

be turned through 90° about the longitudinal axis. These are manual adjustments and no special instructions are required when ordering from the catalogue. LWAKE 4 crossed roller cages consist of roller segments that are assembled according to the length specified by the customer.