Nexen HGP25 969053 - Manual (Page 7)

7 FORM NO. L-21277-B-1213
GENERAL RPS DESIGN GUIDELINES
In order to minimize backlash , obtain the highest positional
accuracy, and minimize wear on the rack, the RPS must
be installed on rigid, straight, flat mounting surfaces with
the tolerances shown in Figures 3 and 4.
The following requirements must be met to ensure proper
RPS operation:
a) Mount a linear guide rail on a surface parallel to the
RPS rack mounting surface with the same flatness as
the rack mounting surface as shown in Figure 4.
b) The pinion shaft must be parallel (±0.03 mm [±0.001
in]) to the rack mounting surface opposite the rack
teeth and the angle between the pinion shaft and the
face of the rack must be 90° ±0.1° maximum as shown
in Figure 3.
Rack
0.03 mm
A
//
0.03 mm
B
0.03 mm
A
//
0.03 mm A
0.03 mm B //
A
B
Figure 4 Tolerances
Additional dimensional detail can be found in Nexen’s
product drawings.
Parallel
HGP
Centerline
Rack
90.0° ±.1°
Figure 3 Pinion Alignment Requirements
This distance must
remain parallel within
±0.03 mm [±0.001 in].
The mounting surface for both the rack and the guiding
system must be parallel within the specifications shown
in Figure 4. This parallelism requirement is best achieved
by machining the mounting locations for both the guiding
system and rack in the same machining operation. (Refer
to SYSTEM ALIGNMENT VERIFICATION section later
in this manual.
The rack must sit on a step at
least one half the width of the
rack for proper support. The
rack should not be supported
by fasteners alone. Pinning the
rack to its mounting surface is
not recommended.
W
1/2 W
Rack
Figure 5 Rack Support Requirements
Nexen recommends orienting the rack teeth downward or
to the side so it minimizes the possibility of debris collecting
on the teeth and causing meshing interference. The rack
has 5 reference surfaces and includes all sides except the
side with the product number. The non-reference face
with the product number should not be placed against
the machine bed surfaces. Any rack ends that have been
cut must be located at the end of the run; the pinion must
not cross cut rack ends.