AU2016299439B2

AU2016299439B2 - Directional force exciter and vibrating machine with directional force exciter

Info

Publication number: AU2016299439B2
Application number: AU2016299439A
Authority: AU
Inventors: Herman DE JONG
Original assignee: Schenck Process Australia Pty Ltd
Current assignee: Sandvik Rock Processing Australia Pty Ltd
Priority date: 2015-07-30
Filing date: 2016-07-28
Publication date: 2019-04-04
Anticipated expiration: 2036-07-28
Also published as: CN107848715B; DE102015009698A1; CN107848715A; DE102015009698B4; WO2017016664A1; AU2016299439A1

Abstract

In the case of a directional force exciter for a vibrating conveyor and/or a vibrating screen, comprising two shafts (4), which are rotatably mounted in a housing by way of at least two bearings each, wherein the bearings have a predetermined bearing play, wherein an eccentric weight is fastened to each of the shafts and a gear wheel (7) is attached to the respective shaft (4), in each case in such a way as to transfer torque, and the gear wheels (7) have a toothing (8) on each, one meshing with the other in an operative relationship, it is provided that the gear wheels (7) are fixed on the respective shaft (4) eccentrically in relation to the axis thereof. The invention also relates to a vibrating machine (1) with such a directional force exciter.

Description

Exciter and Vibration Machine With Exciter

Technical Field

The invention relates to an exciter for a vibrating conveyor and/or a vibrating screen. Exciters are used to drive vibration machines, such as vibrating conveyors and vibrating screens. Compared to the use of unbalance motors, exciters have the advantage that they are able to introduce defined force in one direction and defined mechanical stresses into a vibration machine.

The vibration data is dependent on loads applied by the bulk material.

Background of Invention

Exciters generate a force F having a sinusoidal characteristic, which acts along a line a. An exciter has two shafts aligned with unbalance masses. These unbalance masses are synchronized for counter-clockwise rotation at the same speed due to the builtin toothed-wheel gearset. The components of the centrifugal forces acting in the direction of line a add up to a resulting force F. The components occurring perpendicularly to line a cancel each other out.

Exciters have been developed and marketed for many years. During maintenance work, however, it has been determined time and again that damage occurs to the teeth of the toothed wheels.

A desirable outcome of the present invention is therefore to provide an exciter, in which the known damage may be avoided or at least mitigated. A long-lasting and low-noise exciter design is also to be facilitated, which is furthermore economical to manufacture.

Summary of Invention

According to a first aspect of the present invention there is provided an exciter for a vibrating conveyor and/or a vibrating screen, including: two shafts, which in each case are rotatably supported in a housing via at least two bearings, the bearings having a predetermined bearing play I; an unbalance weight being fastened to each of the shafts; and a toothed wheel being mounted in a torque-transmitting manner to each of the particular shafts, and the toothed wheels each having a toothing, the toothings be-22016299439 22 Feb 2019 ing in active, meshing relationship with each other, wherein the toothed wheels are fastened to the particular shaft eccentrically to the axis thereof to compensate an eccentricity ration arising from the bearing play I.

An exciter for a vibrating conveyor and/or a vibrating screen usually includes two shafts, which are rotatably supported in a housing via at least two bearings. These bearings have a bearing inner race and a bearing outer race, between which the rolling elements are disposed. Depending on the tolerance selected, all bearings have a so-called bearing play I or bearing clearance. This is the degree to which the bearing inner race is displaceable with respect to the bearing outer race in the radial direction from one end position into the other end position.

At least one unbalance weight in each case is fastened to the shafts to generate a directed force F. The latter may be formed in such a way that it has receptacles for additional weights.

A toothed wheel is mounted in each case on the particular shaft in a torquetransmitting manner to drive the unbalance weights and the shaft. For this purpose, the toothed wheel usually has a receiving hole, through which the shaft engages. To secure the toothed wheel on the shaft radially, a feather key extension, in turn, is provided in the receiving hole, which is in engagement in a form-fitting manner with a corresponding securing element on the shaft.

The toothed wheels which are driven counter-clockwise, each have a toothing, the toothings being in active, meshing relationship with each other. According to the invention, the toothed wheels are fixed in the particular shaft eccentrically to the axis thereof.

While a change in the tooth play of the toothed wheels occurs during operation in exciters according to the prior art, due to the existing bearing clearance in self-aligning or cylindrical roller bearings and the centrifugal force of the unbalance weight, it is achieved with the approach according to the invention that the tooth play of the toothed wheels remains almost constant or within a predetermined tolerance range.

The change in tooth play is caused by the action of the centrifugal force of the unbalance weights during operation of the exciter, which induces a displacement of the bearing inner race, and thus the shaft, in the direction of the particular position of the unbalance weight, due to the existing bearing play between the components of the bearing. As a result, the shaft rotates eccentrically. If the unbalance weights move away

-2a2016299439 22 Feb 2019

-32016299439 11 Jan 2018 away from each other, the bearing inner race, in turn, shifts in the direction of the unbalance weights, the shafts, including the fixedly connected toothed wheels, also move away from each other, and the tooth play increases.

If the unbalance weights move toward each other, the tooth play between the two toothed wheels decreases accordingly, due to the contradirectional displacement of the inner race and thus the shaft. This leads to the effect that the toothed wheel tends to get stuck, which may result in the aforementioned damage to the toothing of the toothed wheels.

Structurally, therefore, it has been necessary up to now to provide a large tooth play, which has resulted in a high additional tooth stress and also loud running noise.

Due to embodiments of the present invention, the constant changes in tooth play described above are avoided, since the effects arising from the bearing play may be compensated for by the eccentricity of the toothing with respect to the shaft.

One advantageous embodiment of the present invention therefore provides that the toothed wheels each have a receiving hole for the particular shaft, whose center axis is disposed at an offset x from the toothed wheel center axis.

Another embodiment of the present invention, however, provides that the particular shafts have a shaft shoulder, which engages through a centric receiving hole of the toothed wheel, the axis of the shaft shoulder being disposed at an offset x from the axis of the particular shaft. Due to this arrangement, an eccentricity of the toothing of the toothed wheels with respect to the shaft is also generated. The tooth play, in turn, may thereby be ensured within a predetermined tolerance range during operation of the exciter.

Due to the approach according to embodiments of the present invention, additional startup problems and thermal stresses may be prevented. As a result, the wear on the teeth of the toothed wheels and also the bearing is greatly reduced.

It is furthermore advantageous if bearing plays I of the two bearings and eccentricity x of the toothed wheels with respect to the particular shafts are preselected in such a way that the toothed wheels have a tooth play j during operation which is smaller than or equal to a predetermined maximum value and greater than or equal to a predetermined minimum value, viewed over the entire circumference of the toothed wheels.

-42016299439 11 Jan 2018

The quiet running of the exciter may be ensured thereby, with little wear on the toothed wheels, for example the straight-toothed or helically toothed outer toothing of the toothed wheels.

It has proven to be efficient if the unbalance weight is disposed on the side of a radially outwardly extending feather key receiving extension, viewed from the center of the shaft. The assembly time may be reduced, which culminates in reduced assembly costs, particularly when inserting a feather key into the feather key receiving extension for the purpose of rotatably fixedly mounting the toothed wheel on the particular shaft.

It is also advantageous if the center of the receiving hole is displaced in the direction of the unbalance weight or in the direction of the centrifugal force of the unbalance weight, viewed from the center point of the toothed wheel.

To ensure a particularly fault-free operation, it is advantageous if a feather key receiving extension is present in the receiving hole, in whose direction the center of the shaft accommodated in the receiving hole is displaced/forced.

One advantageous exemplary embodiment is also characterized in that two identical bearings having the same number of bearing plays, such as roller or friction bearings, are used for the two shafts, which are also preferably created in the same manner from shaft to shaft. In this case, equivalent parts are preferably used, which results in a simplified assembly and in lower costs.

If the bearing, preferably all bearings, is/are designed as (self-aligning) roller, spherical or ball bearings, already existing development results may be used as a basis.

According to a second aspect of the present invention there is provided a vibration machine, such as a vibrating conveyor and/or a vibrating screen, which includes an exciter according to the first aspect.

Brief Description of Drawings

Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the present invention will now be explained in greater detail below with reference to the accompanying drawings, where:

Figure 1 shows a side view of a vibration machine, which includes an exciter according to an embodiment of the present invention;

Figure 2 shows an enlargement of area II from Figure 1;

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Figure 3 shows an enlargement of the exciter from Figures 1 and 2 in a perspective representation;

Figure 4 shows a cross-section of an operating exciter from Figures 1 and 2 perpendicularly to the image plane of Figures 1 and 2;

Figure 5 shows a cross section of a bearing from Figure 4 along line V;

Figure 6 shows a cross section of a bearing from Figure 4 along line VI;

Figure 7 shows a side view of a toothed wheel, including a receiving hole, in which a shaft is to be rotatably fixedly accommodated; and

Figure 8 shows a schematic representation of two toothed wheels, which are each mounted on a shaft.

Detailed Description

The figures are only of a schematic nature and are used only for the sake of understanding the invention. Identical elements are provided with the same reference numerals.

Figure 1 shows a vibration machine 1 according to the invention, which is designed as a vibrating conveyor or vibrating screen, an exciter 2 according to the invention being fastened thereto. Exciter 2 introduces force into the vibration machine in the direction of arrows 3.

In Figure 2, exciter 2 is illustrated from the side. It includes two shafts 4, on each of which at least one unbalance weight 5/unbalance mass is mounted. The two shafts 4 are rotatably supported in a housing 6.

In Figure 3, it is apparent that each of the two shafts 4 carries two unbalance weights 5 on each side of housing 6. On the one shaft, they are disposed at a distance from each other, while the unbalance weights of the second shaft are disposed directly next to each other. The space requirements and the distance of the two shafts with respect to each other may thus be optimized, since the unbalance weights of the one shaft use the intermediate space of the two other unbalance weights for their movement.

Within the housing, which is not illustrated in greater detail in Figure 4, each shaft 4 has a toothed wheel 7. The two toothed wheels 7 have a spur toothing on their outside, for example a toothing 8 designed as a straight toothing or helical toothing. The two toothings 8 of the two toothed wheels 7, which are designed as outer toothings,

-62016299439 11 Jan 2018 are in active, meshing engagement with each other. A tooth play j is present between the individual edges of toothing 8.

Each shaft 4 is rotatably supported on two bearings 9. Unbalance weights/unbalance masses 5, which may also be referred to/designed as drive segments, are present on the outside of bearings 9. Arrows 10 indicate the centrifugal forces that occur during operation of exciter 2. Due to their rotation, shafts 4 are also bent, which forces an axial movement of the drive segments toward each other and toothed wheels 7 away from each other.

To achieve an approach according to the invention, an eccentricity x of a receiving hole 11 of toothed wheel 7, into which shaft 4 is inserted, is provided. The receiving hole may be designed as a bore, in particular receiving bore 12. It is then designed in the manner of a through-hole. It has a wall 13, which has a feather key receiving extension 14 on one side.

Eccentricity offset x, between the center of shaft 4 and particular toothed wheel 7, is also illustrated in Figure 8. This ideally corresponds to eccentricity x of bearing inner race 91 with respect to stationary bearing outer race 92. The eccentricity resulting from the bearing clearance is thus compensated for by the eccentricity of toothing 8. Accordingly, the eccentricity is thus dependent on the theoretical bearing play.

However, the approach according to the invention results in tooth play j remaining constant at the point of interaction of toothings 8 over the entire circumference of toothed wheels 7 during operation.

j, in particular ji or j_m, should not be 0 pm, since otherwise no oil film is introducible into the toothed wheel spacing, which results in a great deal of wear and high noise emission.

A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that the document or matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.

-7Where the terms “comprise”, “comprises” and “comprising” are used in the specification (including the claims) they are to be interpreted as specifying the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereof.

2016299439 11 Jan 2018

-7a2016299439 11 Jan 2018 vibration machine exciter excitation force shaft

List of Reference Numerals unbalance weight/unbalance mass housing toothed wheel toothing bearing bearing inner race bearing outer race rolling element centrifugal force receiving hole receiving bore wall feather key receiving extension

Claims

The Claims defining the invention are as follows:

1. An exciter for a vibrating conveyor and/or a vibrating screen, including:

two shafts, which in each case are rotatably supported in a housing via at least two bearings, the bearings having a predetermined bearing play I;

an unbalance weight being fastened to each of the shafts; and a toothed wheel being mounted in a torque-transmitting manner to each of the particular shafts, and the toothed wheels each having a toothing, the toothings being in active, meshing relationship with each other, wherein the toothed wheels are fastened to the particular shaft eccentrically to the axis thereof to compensate an eccentricity ration arising from the bearing play I.
2. The exciter according to Claim 1, wherein the toothed wheels have a receiving hole for the particular shaft, whose center axis is disposed at an offset x from the toothed wheel center axis.
3. The exciter according to Claim 1, wherein the particular shafts have a shaft shoulder, which engages through a centric receiving hole of the toothed wheel, the axis of the shaft shoulder being disposed at an offset x from the axis of the particular shaft.
4. The exciter according to any one of the preceding claims, wherein the bearing plays I of the two bearings and the eccentricity x of the toothed wheels with respect to the particular shafts are preselected in such a way that the toothed wheels have a tooth play j during operation, which is smaller than or equal to a predetermined maximum value and greater than or equal to a predetermined minimum value, viewed over the entire circumference of the toothed wheels.
5. The exciter according to any one of the preceding claims, wherein a radially outwardly extending feather key receiving extension, in whose direction the center of the shaft accommodated in the receiving hole is displaced, is present in the receiving hole.
6. The exciter according to any one of the preceding claims, wherein the toothed wheel fastened to the shaft is disposed axially between the two bearings.
7. The exciter according to any one of the preceding claims, wherein two identical bearings having the same number of bearing plays I are used for the two shafts.

2016299439 22 Feb 2019
8. The exciter according to any one of Claims 5 to 7, wherein the unbalance weight is disposed on the side of the feather key receiving extension, viewed from the center of the shaft or on the opposite side.
9. The exciter according to any one of the preceding claims, wherein the bearing is designed as a (self-aligning) roller, spherical or ball bearing, on the one hand, or as a friction bearing, on the other hand.
10. A vibration machine, which includes an exciter according to any one of Claims 1 to 9.