FLUID MOTOR ROTOR ASSEMBLY

Abstract: A rotor assembly (14) for a fluid powered vane motor has a cylindrical rotor body (16) with front (18) and rear (20) faces, front (22) and rear (24) shaft portions extending axially from the respective faces, and radial slots (28) extending axially along the rotor body. Fixed to the rear face of the rotor body is an end plate (34) which closes the slots at the rear face so as to simplify assembly of the rotor body into the rotor chamber by retaining the vanes in the slots. A front spacer member (36) on the front shaft portion provides positive location of the rotor body with respect to the shaft bearings, and also supports the front end plate (38) which radially circumscribes the spacer member. In other respects, operation of the vane motor containing this rotor assembly is typical of air powered vane motors, in general.

Description: The present invention relates to a rotor assembly for a fluid vane motor. Vane motors are well known and typically include a tubular housing within which a rotor, having radially slidable vanes, is arranged.for rotation about an axis offset from the axis of the tubular housing. Openings through the circumferential sides of the tubular housing or the end plates of the housing define inlet and outlet ports for the fluid motor. Positioning of the ports determines the direction of rotation of the rotor. The ends of the motor cylinder are closed by end plates typically clamped against the end of the cylinder. The end plates also typically support the bearing assemblies for the rotor. The bearings are conventionally located in cavities on the outside of the end plates. Manufacture, assembly, disassembly, and repair of conventional rotor assemblies is difficult because of the complex construction. The end plates and housing members must be disassembled to gain access to the individual components. US-A-4,397,620 describes a vane motor in a rotary compressor which has a cylindrical rotor body defining front and rear faces and vanes supported in the slots. A bolt-on rotor plate is bolted on to each end face of the rotor, these bolt-on plates being necessitated by the provision of diametrically paired vanes and the necessity to attach rotor shafts. The bolt-on plates are not radially coextensive with the rotor body and, after some in-service wear, could be expected to lose power quickly due to the split rotor and/or the multiple diameters of the rotor body and the rotor plates. According to the present invention, there is provided a rotor assembly for a vane motor having a cylindrical rotor body having front and rear faces and front and rear shaft portions extending axially from the respective faces and radial slots extending axially along the rotor body; a front spacer member positioned on the front shaft portion so as to abut the front face of the rotor body; and a front end plate radially circumscribing the front spacer member so as to close the slots at the front face while allowing relative rotation between the spacer and the front end plate, and a rear end plate fixed at the rear face of said rotor body on said rear shaft characterised in that said rear end plate is radially co-extensive with said rotor body so as to close the slots at the rear face. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a cross-sectional side view schematically illustrating an embodiment of a vane motor rotor assembly; and Figure 2 is an exploded perspective view of the vane motor rotor assembly. In Figures 1 and 2, a fluid vane motor includes a hollow cylinder 12 within which a rotor assembly, shown generally by 14, is disposed. The rotor assembly includes a cylindrical rotor body 16 having front 18 and rear 20 faces. A front shaft portion 22 and a rear shaft portion 24 extend axially from the respective front and rear faces. A plurality of radial vane slots 28 extend axially along the outer circumferential surface of the rotor body. The slots are evenly spaced around the circumference. Radial vanes 30 are slidably disposed in each radial slot such that the length of each vane is approximately equal to the length of the rotor body. The length of the rotor body 16 is approximately equal to the axial length of the hollow cylinder 12. The rotor assembly 14 is mounted for rotation within the hollow cylinder about an axis parallel to and offset from the axis of the hollow cylinder. In other words, the rotor assembly rotates in a circular chamber eccentrically offset from the center axis of the hollow cylinder member, as is conventional for vane fluid motors. A rear end plate 34 having an annular shape is fixed to the rear face 20 of the rotor body 16 so as to close the vane slots at the rear face. In the preferred embodiment, for example, the inner diameter of the annular rear end plate 34 may be such that the rear end plate is press fit onto the rear shaft 24. Alternatively, the rear end plate may be fixedly attached in a manner such as welding or may be machined as an integral part of the rotor body 16. A front spacer member 38 has an annular shape. The inner diameter is such that the spacer member can be slid on the front shaft 22 so as to abut the front face 18 of the rotor body 16. Since the spacer 36 rotates with the rotor body 16, it could alternatively be manufactured as a stepped shoulder on the front shaft 22. A front end plate 38 has a larger dimensioned annular shape such that the inner diameter of the front end plate will slide over the outer diameter of the front spacer member 36 so as to allow relative rotation of the spacer member 36, rotor member 16, and the end plate 38. The front end plate 38 radially circumscribes the front spacer member 36 and abuts the front face 18 of the rotor 16 so as to close the slots 28 at the front face. A rear bearing 40, such as an antifriction roller bearing, is positioned on the rear shaft 24 and is retained by means such as a press fit and a retaining ring 42. A front bearing 44 is pressed onto the front shaft 22. The front bearing is axially positioned by the front spacer member 36. The slidable vanes 30 are installed in the vane slots 28 and the completed rotor assembly 14 can now be positioned in a rotor chamber. A forward biasing means such as a wave spring 46 is placed behind the rear bearing 40 to provide bias for axially locating the rotor assembly. A clamp nut 48 is then tightened against the outer race of the front bearing to axially secure the motor parts. The serviceable parts of the rotor of the present invention are easily accessible for maintenance by simply unscrewing clamp nut 48 and removing the rotor assembly 14. The part count compared to a typical conventional vane motor construction is less. Additionally, since the rotor assembly has an integral rear plate 34, the vanes will not slide axially when the rotor assembly 14 is inserted or removed from the rotor chamber. The rear end plate 34 is fixed to the rotor body 16 and rotates with the rotor body. Thus the rotor body is not confined on the rear end by a stationary end plate and can therefore take up axial movement or axial tolerances. Typical steps in assembling a rotor assembly according to the present invention would be as follows: a rear end plate 34 is pressed onto the rear shaft 24 of the rotor body 16. The outer diameter of the completed rotor is then ground to tolerance, the rear end plate 34 being radially coextensive with the rotor body 16. The rear bearing 40 is pressed onto the rear shaft and a retaining ring 42 is positioned to further retain the bearing. The front spacer member 36 is slid on the front shaft 22. The front end plate 38 is slid over the outer diameter of the front spacer 36 so as to circumscribe the front spacer member. The front bearing 44 is pressed onto the front shaft 22. The inner face of the front bearing is ground flush to fit against the face of the spacer member 36 so as to provide the proper clearance between the rotating rotor and the stationary end plate 38. Vanes are disposed in each slot. The rotor assembly 14 is then positioned in the eccentric cylinder chamber to abut against a spring washer 46 which provides bias for forward axial bias of the rotor. The clamp nut 48 is then tightened against the outer race of the front bearing 44 to axially secure the motor parts. The spacer member 36 is clamped tightly between the bearing inner race and the front face 18 of the rotor body. The inner race, spacer member and rotor body thus all rotate as a unit. A power takeoff spindle is located on the front shaft 22 to to provide power takeoff for the rotational force developed by the motor when energized.

Claims: A rotor assembly (14) for a vane motor having a cylindrical rotor body (16) having front (18) and rear faces (20) and front (22) and rear (24) shaft portions extending axially from the respective faces and radial slots (28) extending axially along the rotor body (16); a front spacer member (36) positioned on the front shaft portion (22) so as to abut the front face (18) of the rotor body 16; and a front end plate (38) radially circumscribing the front spacer member (36) so as to close the slots (28) at the front face (18) while allowing relative rotation between the spacer (36) and the front end plate (38), and a rear end plate (34) fixed at the rear face (20) of said rotor body (16) on said rear shaft (24), characterised in that said rear end plate (34) is radially co-extensive with said rotor body so as to close the slots (28) at the rear face (20). An assembly according to claim 1, wherein said front spacer (36) is integrally formed with said front shaft portion (22). An assembly according to claim 1 or 2, comprising a front bearing (44) and a rear bearing (40) for rotatably supporting each respective shaft portion (22, 24). An assembly according to claim 1, 2 or 3, comprising radially sliding vanes (30) supported in the slots (28). An assembly according to any one of the preceding claims mounted in a fluid vane motor including a hollow cylinder (12) having fluid inlet and outlet ports, and the rotor assembly (14) being mounted for rotation within said cylinder (12) about an axis parallel to the axis of said cylinder.

Inventors: ALBERT, GREGORY P.
Applicants: INGERSOLL-RAND COMPANY
Application year: 1990
Main classification: F01C1
IPC codes: F03C2, F01C21