Patent Application
20220268275
The present invention relates to 3D-printing or additive manufacturing. In particular, the present invention relates to a positive displacement pump shaft bearing assembly.
In the field of additive manufacturing an additive manufacturing machine is also called a 3D-printer. In 3D-printing objects or workpieces are built/created/generated by subsequent depositing layers (beads or strands) of build material onto each other. This build material may be molten metal or plastic material and in particular, the depositing process may be the FFF process. The build material supplied to the 3D-printer may be filament or granulated material. Further, said build material may be deposited by a positive displacement pump.
The 3D-printer usually comprises a printhead that moves in three dimensions. Also, there are 3D-printers that comprise printhead that move in two dimensions and a printbed (the surface or structure on/to which the workpiece(s) are created) that moves in the third dimension. Also, there are printheads that are mounted to a conventional industrial robot such that the printhead can realize complex trajectories.
In the field of FFF printing, the printhead may comprise a melt pump or positive displacement pump that is supplied with build material in a depositable state. Such positive displacement pump may comprise at least one rotating shaft. Said build material is deposited through a nozzle that is connected to the positive displacement pump. The deposited build material forms a deposited strand that in turn forms one layer or part of a layer of the workpiece being built.
Positive displacement pumps usually comprise at least one rotating shaft of any sort. The bearing or lodging of said shaft is important for the function and reliability as well as the precision of the positive displacement pump. This precision may comprise inter alia the precision of starting output and/or the precision of the amount of deposited material. The here disclosed shaft bearing is not limited to a specific shaft comprised by a positive displacement pump.
Object of the present application is to improve said shaft bearing and thus increase the precision and reliability of a positive displacement pump.
This object is solved by a shaft bearing assembly for a positive displacement pump or a positive displacement pump shaft bearing assembly according to the appended independent claims.
A positive displacement pump shaft bearing assembly according to an aspect of the present application comprises a shaft having a shaft lodging and a shaft rotational axis. The assembly further comprises a housing having a housing lodging and the assembly further one rolling element that is located between said lodgings. The rolling element comprises a rolling element centre point that coincides with the shaft rotational axis. This may have the advantage that the friction and the break loose torque of the shaft is reduced. Consequently, the amount of build material deposited by the positive displacement pump may be controlled more finely. Also, the wear of the positive displacement pump is reduced. The positive displacement pump may be a gear pump and the rolling element may have any suitable form. The rolling element centre point is the geometrical centre point or middle point of the respective rolling element. Every rotational axis (rolling movement) of the respective rolling element passes through the rolling element centre point.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein at least one of the shaft lodging and/or the housing lodging has one lodging form among: a conical-shape, a sphere-shape, a sphere-recessed-shape. This may have the advantage that the wear of the lodging is reduced. Also, the break loose torque is reduced.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein the rolling element has point or line contact with the shaft lodging and/or the housing lodging. This may have the advantage that the wear of the lodging is reduced. Also, the break loose torque is reduced.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein the shaft lodging and/or the housing lodging is adjustable in position parallel to the shaft rotational axis. This may have the advantage that the play within the shaft bearing assembly may be adjusted.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein the shaft and/or housing lodging is threadedly connected with the shaft and/or the housing. This may have the advantage that the play within the shaft bearing assembly may be adjusted. Also, this may have the advantage that the maintenance of said assembly is facilitated.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein at least one distance element is located between the shaft lodging and/or the housing lodging and the rolling element or at least one distance element is located between the shaft lodging and/or the housing lodging and the shaft and/or housing. This may have the advantage that the play within the shaft bearing assembly may be adjusted.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein at least one fluid line is connected with the shaft lodging and/or the housing lodging. This may have the advantage that fluid may be supplied to the lodging. The fluid may for example be air or lubricant and/or coolant.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein at least one of the shaft lodging, the housing lodging and the rolling element is case hardened and/or coated. This may have the advantage that wear of said assembly is reduced.
A shaft bearing assembly according to another aspect of the present application is disclosed wherein the rolling element is made from at least one of: metal or ceramics. This has the advantage that the material for the rolling element may be chosen according its coefficient of thermal expansion. By knowing the dimensions of the shaft bearing (e.g. size of the rolling element and dimensions of the housing and shaft lodging) and the operating temperature, the play of the shaft bearing assembly can be chosen/adjusted. Also, the rolling element may be a material mixture, e.g. having a metal core with a ceramic outer layer or vice versa.
According to another aspect of the present application a positive displacement pump is disclosed, comprising at least one shaft bearing assembly according to any of the above aspects. This may have the advantage that the positive displacement pump may have an increased precision. Even if a shaft of the shaft bearing assembly has two or more bearings or lodgings, only one may comprise a shaft bearing assembly according to the present invention. In other words, in a positive displacement pump not all bearings or lodgings have to be of the here disclosed kind.
A positive displacement pump according to another aspect of the present application may be a gear pump. This may have the advantage that the precision of said positive displacement pump may further be increased.
The above aspects may be freely combined. For a better understanding of the invention the latter will be explained in view of the appended figures. The figures respectively show in very simplified and schematically depiction:
It is to be noted that in the different embodiments/variations described herein same parts/elements are numbered with same reference signs, however, the disclosure in the detailed description may be applied to all parts/elements having the regarding reference signs. Also, the directional terms/position indicating terms chosen in this description like up, upper, down, lower downwards, lateral, sideward are referring to the directly described figure and may correspondingly be applied to the new position after a change in position or another depicted position in another figure.
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In all figures like reference sings are used for like or similar parts/elements as in the other figures. Thus, a detailed explanation of such part/element will only be given one for the sake of brevity.
The embodiments depict possible variations of carrying out the invention, however, it is to be noted that the invention is not limited to the depicted embodiments/variations but numerous combinations of the here described embodiments/variations are possible and these combinations lie in the field of the skills of the person skilled in the art being motivated by this description.
The scope of protection is determined by the appended claims. The description and drawings, however, are to be considered when interpreting the claims. Single features or feature combinations of the described and/or depicted features may represent independent inventive solutions. The object of the independent solutions may be found in the description.
All notations of ranges of values in the present description are to be understood as to also comprise and disclose all arbitrary sub-ranges therein, e.g. the disclosure 1 to 10 is to be understood that all sub-ranges starting from the lower limit 1 up to the upper limit 10 are also comprised and disclosed, i.e. all sub-ranges starting with a lower limit of 1 or bigger and end with an upper limit of 10 or smaller, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10. Only one digit after the comma is described, however the same applies mutates mutandis to any given number of digits after the comma.
It is further to be noted that for a better understanding parts/elements are depicted to some extend not to scale and/or enlarged and/or down scaled.
| Number | Date | Country | Kind |
|---|---|---|---|
| LU101339 | Jul 2019 | LU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/071346 | 7/29/2020 | WO |
