Rotor vane and shaft assembly

A rotor assembly includes a shaft and a planar vane extending in a radial direction from the shaft and having a peripheral groove receiving a resilient sealing gasket. The vane includes a tongue portion which depends into a radial cavity in the shaft and is sealably cemented thereto. Radially extending ribs on the ends of the tongue are accurately fitted against the ends of the cavity which are aligned with the adjacent ends of the bottom walls of the peripheral groove.

The present invention relates in general to the construction of a rotor for 
use in a rotary actuator or the like, and it relates in particular to a 
new and improved rotor shaft and vane assembly and to a method of making a 
rotor comprising a shaft and attached vane. 
BACKGROUND OF THE INVENTION 
Rotary actuators such as rotary motors and rotary pumps commonly utilize a 
rotor which includes a vane which extends radially from a shaft into a 
liquid-filled chamber into which a fixed stator vane or blade extends in a 
radial direction. In the case of a pump rotation of the rotor from an 
external drive forces liquid from the leading side of the rotor vane to 
the trailing side through an external conduit including a load. In the 
case of an actuator or motor, liquid is pumped into the chamber on one 
side of the rotor vane which thus imparts a torque to the rotor causing 
angular movement thereof. One such rotary actuator is described in detail 
in U.S. Pat. No. 4,495,856. 
A major problem which is inherent with these types of devices is the 
leakage of the hydraulic fluid around the edges of the rotor vane from the 
high pressure side to the low pressure side of the chamber, and the most 
troublesome leakage area is at the corners of the vane where it adjoins 
the shaft and the associated housing. Extremely small dimensional 
tolerances must be maintained, and this has resulted in relatively high 
manufacturing costs. 
SUMMARY OF THE INVENTION 
Briefly, there is provided in accordance with the present invention a new 
and improved method of attaching a vane to a shaft and to a novel vane and 
shaft assembly for use in a rotary actuator or the like. In a preferred 
embodiment a generally planar vane or blade is provided with an elongated 
tongue which is coplanar with the vane and is fitted into a radial slot in 
the shaft. The vane is provided with a peripheral groove which is adapted 
to receive a generally U-shaped elastomeric sealing gasket to provide a 
seal between the vane and the adjacent surfaces of the housing. The tongue 
is provided with a plurality of raised ribs disposed on the sides and ends 
thereof and the slot has a depth which is slightly greater than the 
corresponding dimension of the tongue to provide a cavity in the shaft at 
the distal end of the tongue. 
The dimensions of the vane and slot are chosen to provide a snug fit 
between the ends of the slot and the ribs located at the respective ends 
of the tongue to align the ends of the tongue with a pair of annular 
shoulders on the shaft and to provide an airtight seal between the shaft 
and the tongue along the entire lengths of the ribs. The outer end 
surfaces of the end ribs are aligned with the bottoms of the adjacent 
portions of the peripheral groove whereby leakage between the shaft and 
the end portions of the vanes is prevented by the associated sealing 
gasket. The cavity at the bottom of the tongue and the spaces on the sides 
and ends of the tongue are filled with an epoxy which bonds the vane to 
the shaft and prevents leakage of hydraulic fluid between the tongue and 
the shaft.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
Referring particularly to FIG. 1, a rotor assembly 10 may be seen to 
include a shaft 12 having an intermediate cylindrical section 14 located 
between first and second end sections 16 and 17 of lesser diameter. 
Annular shoulders 19 and 20 are provided at the intersections of the end 
sections and the intermediate section. 
A vane 22, which is generally rectangular in configuration, has opposite 
planar faces 24 and 25 separated by a generally U-shaped edge 26 in which 
a peripheral groove 28 is provided. The groove 28 is rectangular in 
cross-section and is adapted to receive a U-shaped elastomeric gasket 30 
as shown in FIG. 4. As may be seen in FIG. 4, the gasket 30 extends 
outwardly beyond the adjacent marginal edges 26 of the vane and the two 
ends of the gasket 30 abut the adjacent surfaces of the shaft and are 
compressed against it when the rotor assembly is operatively mounted in an 
associated housing (not shown). 
The intermediate section 14 of the shaft is provided with a longitudinally 
elongate cavity 31 which is arcuate at its two ends and which extends in a 
radial direction toward the center of the shaft as best shown in FIG. 4. A 
tongue 32 is an integral part of the vane 22 and has a side wall which is 
generally complimentary to the side wall of the cavity 31, but somewhat 
smaller to provide a space in the cavity which surrounds the tongue. A 
plurality of rectilinear ribs 34 and 35 are provided at the respective 
ends of the tongue as best shown in FIG. 3, and a second plurality of 
rectilinear ribs 37, 38 and 39 are provided on the sides of the tongue. 
With the tongue 32 in place in the cavity 31 the end ribs 34 and 35 fit 
snugly against the end walls of the cavity while an accurate close fit is 
provided along the sides of the tongue. An imperforate bonding material 
such as an epoxy 41 fills the remainder of the cavity including the space 
42 between the bottom of the cavity and the adjacent end of the tongue 32. 
The bonding material 41 also fills the generally triangular spaces 44 and 
45 located between the shaft 12 and the shoulders 48 and 49 at the 
juncture of the tongue and body portions of the vane 32 shown in FIG. 4. 
It will also be seen that the outer edges of the end ribs 34 and 35 are 
respectively aligned with the bases or bottom surfaces 51 and 52 of the 
peripheral groove 28 in the vane 22. As a consequence, an airtight seal is 
provided between the tongue and the shaft and the gasket 30 provides a 
seal between the shaft and the portions of the vane which extend 
longitudinally beyond the ends of the tongue. 
It is important that the ends of the vane 22 be aligned with the annular 
shoulders 19 and 20 and such alignment is assured by virtue of the snug 
fit between the end ribs 34 and 35 and the ends of the cavity 31. 
While the present invention has been described in connection with a 
particular embodiment thereof, it will be understood by those skilled in 
the art that many changes and modifications may be made without departing 
from the true spirit and scope of the present invention. Therefore, it is 
intended by the appended claims to cover all such changes and 
modifications which come within the true spirit and scope of the present 
invention.