Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-10-07
2001-04-10
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S086000, C417S423140
Reexamination Certificate
active
06215215
ABSTRACT:
PRIOR ART
The invention relates to an electric motor, for driving a pump unit.
The invention is based on an electric motor. DE 44 30 909 A1 has already disclosed an electric motor that is for driving a radial piston pump and is fastened to a connecting block for connecting the electric motor to the radial piston pump. The connecting block simultaneously constitutes the housing of the radial piston pump. In order to drive the pump pistons of the radial piston pump, a cam is embodied on the shaft of the motor. Inside a motor housing, the shaft supports an armature which cooperates with a stator in a known manner. The motor housing is embodied in the shape of a cup and, on the end face adjoining the connecting block, is closed by a motor cover. The motor cover has a peripheral section extending essentially radial to the shaft and an inner section extending essentially axial to the shaft. The inner section encloses an outer bearing shell of a ball bearing radially and on one side also axially. This ball bearing is one of a total of three bearings with which the shaft is supported in the motor housing, the motor cover, and the connecting block. The motor is fastened to the connecting block in such a way that the motor cover is screw connected to the connecting block.
With a known electric motor, the disadvantage is that it has a tendency to produce significant noise due to the rigid connection with the connecting block. In the known electric motor, it is also disadvantageous that the radial forces occurring in the middle bearing are not completely absorbed by the motor cover, which likewise contributes to noise production.
ADVANTAGES OF THE INVENTION
The pump unit according to the invention, has an advantage that the motor housing and the motor cover are prestressed by means of a clamping element. The motor cover can favorably compensate for existing manufacture-induced axial tolerances. Because the motor cover is clamped due to the detent connection of the peripheral section of the motor cover to the motor housing and due to the contact against the support, a force component that is directed radially outward is exerted on the inner section of the motor cover, which better fixes the bearing encompassed by the inner section. Radial forces that are exerted onto the bearing, particularly with the use of the electric motor in connection with a radial piston pump, therefore contribute significantly less to noise production.
Another advantage lies in the simplified manufacture of the electric motor. Since axial tolerances in the connection between the motor cover and the connecting block due to the axial clamping of the motor cover are largely prevented, significantly fewer demands have to be placed on the manufacture tolerances. This contributes to a reduction in production costs.
Advantageous improvements and updates of the electric motor are possible by means of the measures taken as set forth hereinafter.
The disposition of the support in the vicinity of the bearing enclosed by the inner section of the motor cover produces a particularly great lever arm with which the clamping force transmitted by the motor housing acts on the motor cover. Axial tolerances of the motor cover are thus compensated for in a particularly favorable manner. Furthermore, due to the favorable ratio of the lever arms, a relatively high radial force component is produced with which the inner section of the housing cover acts on the bearing that it radially encloses.
The clamping element is preferably comprised of locking screws which extend through the motor housing parallel to the shaft. The locking screws can be tightened from the outside by means of a suitable tool on the side of the motor housing disposed opposite from the connecting block. Preferably, the locking screws are disposed evenly around the circumference of the shaft. In this manner, the clamping force can be apportioned so that it is distributed over the circumference. If the inner section of the motor cover encompasses the bearing in a cup-shaped fashion, a particularly favorable contact is produced between the inner section and the outer bearing shell of the bearing.
In order to lock the motor cover in place, the motor housing can have a corresponding step, which can be manufactured in a particularly simple and inexpensive manner in the mass production, e.g. by means of caulking or stamping. Preferably, a sealing means for sealing the gap is provided between the connecting block and the outer circumference of the peripheral section of the motor cover and/or the motor housing. In this fashion, moisture and impurities are prevented from penetrating into the gap. The sealing means can be inserted into a contour hollow between the motor housing and the motor cover or can be inserted into a concavity provided for this, which enlarges the contour hollow. An additional or alternative sealing means can also be provided in the vicinity of the support. In this connection, the support can be embodied as an axial projection of the motor cover and a first sealing means can be provided radially inside the axial projection of the motor cover and a second sealing means can be provided radially outside this projection. The sealing means can in particular be inserted into a contour hollow that is embodied at the transition from the peripheral section to the inner section of the motor cover.
Preferably the sealing means is comprised of a hardening sealing medium, such as silicone. Preferably in the as yet unhardened state, the sealing medium is applied to the motor cover, the motor housing, or the connecting block before these parts are assembled. This produces a particularly tight seal between the components and additionally damps the transmission of vibrations, which further reduces the noise emission of the motor. Alternatively, elastic sealing rings, e.g. O-rings, can be used as the sealing means.
The inner section of the motor cover can advantageously be embodied as conical at least in a partial region and can cooperate with a correspondingly conical section of a bore of the connecting block, which bore contains the inner section of the motor cover. In particular, this has the advantage that a part of the radial bearing forces of the bearing, which is radially enclosed by the inner section of the motor cover, are introduced directly into the connecting block and consequently, a particularly good radial support of the bearing is produced. This also counteracts noise emission.
REFERENCES:
patent: 3746472 (1973-07-01), Rupp
patent: 5412272 (1995-05-01), Mensching
patent: 5564909 (1996-10-01), Rischen et al.
patent: 5742109 (1998-04-01), Volz et al.
Bitzer Harold
Braun Wilhelm
Huber Martin
Dinh Le Dang
Greigg Edwin E.
Greigg Ronald E.
Ramirez Nestor
Robert & Bosch GmbH
LandOfFree
Electric motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2500502