Abstract
An oscillation excitation device for producing oscillations and/or vibrations includes an electric motor which has a stator unit and a rotor unit that can be rotated about an axis of rotation and has at least one rotor shaft. At least a first bearing unit and a second bearing unit are provided for rotatably mounting the rotor shaft and/or rotor unit. At least one electromagnetic drive system of the electric motor is arranged between the first bearing unit and the second bearing unit. At least one rotatable imbalance unit is provided for producing an imbalance. The imbalance unit is arranged, at least in part, between the first bearing unit and the second bearing unit.
Claims
1. An oscillation excitation device for producing oscillations and/or vibrations, comprising: an electric motor having a stator unit and having a rotor unit which is rotatable about a rotation axis and which has at least one rotor shaft; at least a first bearing unit and a second bearing unit that are configured to rotatably support at least one of the rotor shaft and the rotor unit, wherein the electric motor has at least one electromagnetic drive system that is disposed between the first bearing unit and the second bearing unit, and further comprising at least one rotatable imbalance unit that is configured to produce an imbalance, wherein the imbalance unit is disposed, at least in part, between the first bearing unit and the and the second bearing unit.
2. The device as claimed in claim 1, wherein the rotor shaft is configured as an imbalance unit.
3. The device as claimed in claim 1, wherein the rotor unit has at least one support unit that is configured to support rotor components of the electromagnetic drive system.
4. The device as claimed in claim 3, wherein the support unit is configured as an imbalance unit.
5. The device as claimed in claim 1, wherein the imbalance unit is disposed at least in part within a motor housing of the electric motor.
6. The device as claimed in claim 1, wherein the imbalance unit comprises at least one first eccentric element, and wherein a first spacing is provided between a first center of gravity of the first eccentric element and the rotation axis.
7. The device as claimed in claim 6, further comprising at least one adjustment unit which is configured to vary the first spacing between the first center of gravity of the first eccentric element and the rotation axis.
8. The device as claimed in claim 6, wherein the adjustment unit comprises at least one restoring spring element that is configured to produce a restoring force which is, at least in part radially aligned with the first eccentric element and which acts on the first eccentric element.
9. The device as claimed in claim 6, wherein the imbalance unit comprises at least the first eccentric element and a second eccentric element which has a second center of gravity, wherein the second center of gravity is, at least temporarily, disposed so as to be different from the first center of gravity of the first eccentric element.
10. The device as claimed in claim 9, wherein at least one of the first eccentric element and the second eccentric element is configured as an eccentric element which is rotatable about at least one of the rotation axis and the rotor shaft.
11. The device as claimed in claim 1, further comprising at least one detent for the for the eccentric element, wherein the detent is rotatable about at least one of the rotation axis and the rotor shaft.
12. A compactor for compacting soil or concrete engineering or construction site engineering or foundry technology or sorting objects, the compactor comprising: an oscillation excitation device for producing oscillations and/or vibrations, the oscillation device including an electric motor having a stator unit and having a rotor unit which is rotatable about a rotation axis and which has at least one rotor shaft; at least a first bearing unit and a second bearing unit that are configured to rotatably support at least one of the rotor shaft and the rotor unit, the electric motor having at least one electromagnetic drive system that is disposed between the first bearing unit and the second bearing unit; and at least one rotatable imbalance unit hat is configured to produce an imbalance, wherein the imbalance unit is disposed, at least in part, between the first bearing unit and the and the second bearing unit.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] An exemplary embodiment of the invention is illustrated in the drawing and will be explained in more detail hereunder by means of the figures in which:
[0028] FIG. 1 shows a schematically illustrated cross section through a first electric motor, configured as an asynchronous motor, according to the invention;
[0029] FIG. 2 shows a schematically illustrated cross section through a second electric motor, configured as an asynchronous motor, according to the invention;
[0030] FIG. 3 shows a schematically illustrated cross section through a third electric motor, configured as a synchronous motor, according to the invention;
[0031] FIG. 4 shows a schematically illustrated cross section through a fourth electric motor, configured as an asynchronous motor, according to the invention, having a separate, radially adjustable imbalance weight;
[0032] FIG. 5 shows a schematically illustrated cross section through a fifth electric motor, configured as an asynchronous motor, according to the invention, having a separate imbalance weight which is rotatable about the rotation axis and is illustrated in two different detent positions; and
[0033] FIG. 6 shows a schematically illustrated longitudinal section through a sixth electric motor according to the invention, having two imbalance weights which are disposed on the rotor shaft so as to be on both sides of the drive system of the rotor.
DETAILED DESCRIPTION
[0034] Various electric motors 1 according to the invention in FIGS. 1 to 6 are illustrated in a schematic manner and perpendicular to the rotation axis in a cross section through an electromagnetic drive system of the motor 1, the latter being generally known and not illustrated in more detail. The electric motor 1 comprises substantially a rotor 2 and a stator 3 which has an outer a motor housing 4. The rotor 2, for example according to the figures, is configured in such a manner that said rotor 2 comprises a rotor shaft 16, or a rotor shank 14, respectively, and a support 15 for the electromagnetic drive components.
[0035] The stator 3 in a manner known moreover comprises two so-called bearing brackets 18 (cf. FIG. 6) which are disposed along the rotation axis and on both sides of the electromagnetic drive system, one bearing unit 17, or advantageously one or two roller bearings 17 for mounting the rotatable rotor 2, respectively, being in each case disposed in said bearing brackets 18. The bearing brackets 18, or bearing receptacles 18, respectively, in the context of the invention are a component part of the motor housing 4 such that a completely closed-off motor housing 4 in the context of the invention is realized. As a result, the ingress of dirt, dust and water can particularly effectively advantageously be prevented, as a result of which high requirements in terms of the safety and the service life of the motor 1 can be met.
[0036] In both variants of FIGS. 1 to 6, the rotor 2 at the same time is advantageously configured as an imbalance unit 5 according to the invention, or the imbalance unit 5 is disposed between the bearing 17 or bearing brackets 18, or in the region of the electromagnetic drive system, respectively. Separate imbalance weights 5 can optionally also be present along the rotation axis so as to be outside the bearing brackets 18 or the electromagnetic drive system, respectively.
[0037] In the first variant according to FIG. 1, the rotor 2 of the electric motor 1, configured as an asynchronous motor, is configured so as not to be symmetrical in relation to the rotation axis but occupies only approximately half of the circular cross section. This means that the rotor 2 extends only across approx. 180° of the circumference of the circle, the other half of the cross section comprising only air 6 or being configured as a recess 6 in the context of the invention, respectively, no material/metal and electromagnetic drive components thus being present. Accordingly, the center of gravity, or the center of the cross-sectional area, respectively, is mounted so as to be eccentric, or provided so as to be eccentric with a spacing from the rotation axis, respectively. An advantageous, relatively large imbalance is thus generated, which in the operation, or at a rotating rotor 2, respectively, leads to the electric motor 1 advantageously generating vibrations, or being able to be used as a vibrator/oscillation exciter, respectively.
[0038] By virtue of the rotor 2 according to FIG. 1 extending only across approx. 180° of the circumference of the circle, this electric motor 1 has a torque which is about half the torque of an electric motor 1 in which the electromagnetic drive system would be present on the entire circumference. Advantageous variant of this type, having an electromagnetic drive system on the entire circumference, is illustrated in FIG. 2. It can thus be readily seen in FIG. 2 that the so-called return openings extend across the full 360° of the cross section of the rotor 2, this generating an advantageous torque or a relatively high motor output, respectively.
[0039] In this second variant according to the invention, the recess 6, or the air 6, respectively, is enclosed entirely by the rotor 2, or a rotor casing, respectively. An advantageous imbalance 5 according to the invention is also realized herewith.
[0040] In the third variant according to FIG. 3 the electric motor 1 is configured as a synchronous machine having permanent magnets 7 which are disposed on the circumference. In a highly schematic manner, two south poles 8 of the permanent magnets 7 are illustrated as white areas and two north poles 9 of the permanent magnets 7 are illustrated as black areas in FIG. 3. Accordingly, a total of four poles are present which in practice is certainly rather rare. However, this is only intended to illustrate the principle because electric motors of this type in practice usually have many permanent magnets 7 and thus many poles.
[0041] In the fourth variant according to FIG. 4 the rotor 2 again has a recess 6 or air 6, respectively, which is completely enclosed by the rotor 2 or the rotor casing, respectively. An advantageous imbalance 5 according to the invention is also realized herewith. Moreover, a separate weight 10 is however disposed within the recess 6 or the air 6, respectively, said separate weight 10 being held/positioned by a spring 11 which is aligned in a radial direction. Because the weight 10 does not have a circular shape, said weight is also configured as an imbalance 5 in the context of the invention and disposed along the rotation axis so as to be between the two bearing brackets or bearings, respectively, in the region of the electromagnetic drive system.
[0042] The weight 10 is advantageously adjusted in the radial direction as a function of the rotating speed of the rotor 2 as well as of the spring force. The effective imbalance mass thus decreases as the rotating speed increases because the centrifugal force pushes the weight 10 radially outward in the direction of the rotor casing. As the rotating speed decreases, the weight 10 “travels” back in the direction of the rotation axis or the center, respectively. An advantageous adaption/variation of the effective imbalance mass or the oscillation excitation, respectively, can be implemented herewith.
[0043] In the fifth variant according to FIG. 5, a separate weight 12 is again present, said weight 12 however not being disposed within the recess 6 of the laminated rotor core but being axially offset, for example along the rotation axis in a free void, or another plane/layer, respectively, between two laminated cores but within a rotor casing which extends over the entire circumference, or between this rotor casing and a rotor shank 14, respectively. As a result of this advantageous void and the advantageous shape of the weight 12, the latter is mounted so as to be rotatable about the rotation axis or the rotor shank 14, respectively.
[0044] By virtue of the inertia of the weight 12, the latter as a function of the rotating direction impacts in each case a detent 13 at the end side (cf. FIG. 5a) and FIG. 5b)). The detent 13 is aligned in the direction of the rotation axis, or so as to be parallel to the rotation axis, respectively. The detent 13 is advantageously disposed within the above-mentioned void, or extends between the two above-mentioned laminated cores/layers/planes which are correspondingly spaced apart from one another, respectively. In the position of the weight 12 according to FIG. 5a), a subtraction of the imbalance of the weight 12 conjointly with the imbalance of the laminated rotor core, or the rotor body, respectively, is thus realized and even a complete elimination of the overall imbalance is optionally enabled in the case of an advantageous sizing.
[0045] In the position of the weight 12 according to FIG. 5b), an addition of the imbalance of the weight 12 conjointly with the imbalance of the laminated rotor core or the rotor body, respectively, is realized and thus increased. This variability of the total imbalance as a function of the rotating direction of the rotor 2 can be a great advantage in specific fields of application.
[0046] In the sixth variant according to FIG. 6, the electric motor 1 is configured according to the invention in such a manner that, according to the variant depicted, a total of two imbalance elements 5 are disposed/fixed on both sides of the electromagnetic drive system, or both sides of the rotor support 15 on/on top of the rotor shaft 16, respectively. According to the invention, these two weights or imbalance elements 5, respectively, are disposed between the two bearings 17 or ball bearings 17, respectively, and between the two bearing brackets 18 of the motor housing 4. Consequently, the two weights or imbalance elements 5, respectively, are disposed and protected within the mounting of the rotor shaft 16 and moreover also within the motor housing 4 or in the interior of the latter, respectively.
