Thrust and cover washer, mounted on a rotor shaft, for a bearing of the rotor shaft

In order to ensure full-surface thrust contact and coverage despite a low production and assembly outlay, even if the bearing is mounted slightly askew, a thrust and cover washer may be used which includes an inelastic first annular washer part axially thrusting and not contacting the rotor shaft, and an elastic second annular washer part positively joined thereto and resting sealingly on the rotor shaft. The first annular washer part may advantageously be made of plastic and the second annular washer part may advantageously be made of an elastomer.

BACKGROUND OF THE INVENTION 
The present invention relates to a thrust and cover washer, mounted on a 
rotor shaft, for a bearing of the rotor shaft. An axially thrusting 
inelastic first annular washer part is included which is not in contact 
with the rotor shaft. An elastic second annular washer part is positively 
joined to the rotor shaft and rests sealingly on the rotor shaft. Thrust 
washers or cover washers of this kind may be used on the one hand for 
axial, preferably damped, thrust of the rotor against a bearing receiving 
the rotor shaft, and on the other hand to protect the rotor, in particular 
of a commutator of a commutator motor, against emerging bearing oil which 
is to be returned to the bearing or to a lubricant reservoir of the 
bearing. 
SUMMARY OF THE INVENTION 
The present invention guarantees, with little production and assembly 
outlay and even in the presence of a possible slight skewing of the 
bearing which is unavoidable in the production of mass-produced items, 
full-surface thrust contact and complete coverage by the thrust and cover 
washer. This is achieved by a thrust and cover washer including an axially 
thrusting inelastic first annular washer part and an elastic second 
annular washer part. The axially thrusting inelastic first annular washer 
part is not in contact with the rotor shaft. The elastic second annular 
washer part is positively joined to the rotor shaft and rests sealingly on 
the rotor shaft. The thrust and cover washer may be mounted on the rotor 
shaft between a spherical cap bearing and a commutator of a commutator 
motor. Other advantageous embodiments of the present invention may be 
implemented according to the following description and the attached 
drawings. 
A two-part thrust and cover washer may be configured according to an 
embodiment of the present invention, in which a first annular washer part 
is preferably made of plastic and a second annular washer part is 
preferably made of an elastomer. This two-part thrust and cover washer 
guarantees reliable mutual immobilization between the inelastic and 
elastic washer parts even as the washer is being delivered and mounted 
onto the rotor shaft. The two-part thrust and cover washer also guarantees 
complete sealing of the bearing against emerging bearing oil, even if the 
bearing is in a slightly skewed position.

DETAILED DESCRIPTION 
In a cup-shaped bearing bracket 1 of a commutator motor, one commutator 2 
is rotatably mounted in a spherical cap 3, with a rotor shaft 6 receiving 
commutator plates 2.1 arranged on the periphery. Spherical cap 3 rests 
with its left spherical outer surface against the end of bearing bracket 
1, and is locked axially in position by a clamping stay 3.1, resting 
against the right spherical outer surface. The right spherical outer 
surface in turn is immobilized on its outer edge with respect to the 
cup-shaped bearing bracket 1 by jamming. A lubricant reservoir 7 is 
provided above spherical cap 3, by the corresponding cup-shaped 
configuration of bearing bracket 1. Lubricant for spherical cap 3 is 
stored in lubricant reservoir 7. This lubricant is preferably manufactured 
from sintered material. 
The thrust and cover washer configured according to an embodiment of the 
present invention is mounted onto rotor shaft 6, between the end surface 
of cap 3 toward the clamping stay on the one hand and the opposing end 
surface of commutator 2 on the other hand. The thrust and cover washer is 
mounted onto rotor shaft 6 in such a way that it axially covers the 
reservoir and bearing space with respect to commutator 2 and, in 
particular, by means of an axially projecting thrust ring 4.2, ensures 
that the rotor is thrust against spherical cap 3 during operation. 
The thrust and cover washer includes, and in a preferred embodiment, 
consists substantially of, an inelastic first annular washer part 4 which 
is preferably injection-molded from plastic, and an elastic second annular 
washer part 5, joined at least positively thereto and preferably made of 
an elastomer. This elastic second annular washer part 5 advantageously 
guarantees sealing with respect to rotor shaft 6, and sufficient 
elasticity such that the thrust and cover washer can, by slight tilting of 
a spherical cap with a slight assembly-related skew, adapt to thrust 
contact with no loss of the sealing effect against rotor shaft 6. 
For axial and radial positive immobilization between the first annular 
washer part 4 and the second annular washer part 5, the first annular 
washer part 4 has, in the region of its opening toward the rotor shaft, a 
radially projecting retaining ring 4.1 of small axial extension which is 
surrounded by the elastic second annular washer part 5 in the form of an 
axial or radial undercut 5.1. This reliably prevents detachment of the 
elastic second annular washer part 5 from the inelastic first annular 
washer part 4 during transport and sealing placement onto rotor shaft 6 
and during operation. In particular, because of the small axial extension 
of the radially projecting retaining ring 4.1, this also promotes a slight 
tilting of the thrust and cover washer to adapt to a spherical cap 3 
assembled slightly askew. The radial dimensions of the rotor shaft opening 
of the first annular washer part 4 and of the second annular washer part 
5, and the elasticity thereof, are to be defined in such a way that when 
the thrust and cover washer is mounted onto rotor shaft 6, sufficient 
mutual pressure is achieved in the interest of the desired sealing. 
For tangential locking between the inelastic first annular washer part 4 
and the elastic second annular washer part 5, spokes 5.3 which engage in 
the circumferential direction between axial projections 4.6 of the first 
annular washer part 4 in the interest of rotational locking and, in the 
interest of sufficient stability, are joined to one another by an outer 
ring 5.2 which is preferably injection-molded onto spokes 5.3, and are 
injection-molded onto the radially inner part which provides axial and 
radial immobilization. 
The elastic second annular washer part 5 can be joined to the inelastic 
first annular washer part 4 as an initially separate component, in 
particular by being pushed on, or can be injection-molded onto it in the 
manner described above, thereby ensuring positive immobilization by means 
of undercuts. 
According to one embodiment of the present invention, the elastic second 
annular washer part 5 is equipped at its end surface facing commutator 2 
with a support and sealing ring edge 5.4, preferably integrally 
injection-molded on, which serves both as an axial impact damper and also 
as an additional seal, especially if the thrust and cover washer is in a 
slightly skewed position, when thrust against a correspondingly skewed 
spherical cap 3. 
The inelastic first annular washer part 4 has on its end surface facing 
spherical cap 3, radially outside its axially projecting thrust edge 4.2, 
a first circumferential slinger edge 4.3, and at a further radial distance 
a second circumferential slinger edge 4.4 for additional covering 
protection against emerging bearing oil. The two slinger edges 4.3 and 4.4 
ensure that any bearing oil which emerges is slung against the inner wall 
of the cup-shaped bearing bracket 1 and thus returned to lubricant 
reservoir 7, which is delimited on the outside by the bearing bracket 1. 
As an additional measure to return any bearing oil which emerges, a runoff 
bevel 4.5 is advantageously provided on the outer edge of the first 
annular washer part 4. The runoff bevel 4.5 is oriented toward spherical 
cap 3 such that emerging bearing oil is returned to slinger edges 4.4 and 
4.3 lying radially below, and in particular, even when rotor shaft 6 is 
stationary or running slowly.