WO2020182450A1

WO2020182450A1 - A feeding mechanism used in 3d printers

Info

Publication number: WO2020182450A1
Application number: PCT/EP2020/054713
Authority: WO
Inventors: Kemal OKTAY; Celal Vatansever; Ersin Donmez; Omer Burak Coban; Varol KAYISDAG
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2019-03-11
Filing date: 2020-02-24
Publication date: 2020-09-17
Anticipated expiration: 2021-09-11

Abstract

The present invention relates to a three-dimensional printer (1) comprising a motor (2); a motor shaft (3); and a feeding mechanism (4) having two unidirectional ball bearings (5 and 6) which are mounted to said motor shaft (3) one behind the other, two drive gears (7 and 8) which are coaxially mounted onto the two ball bearings (5 and 6), and two guiding members (9 and 10) which extend parallel to the motor shaft (3) next to each drive gear (7 and 8), wherein the filament (15) is inserted between the drive gear (7 and 8) and the guiding member (9 and 10).

Description

A FEEDING MECHANISM USED IN 3D PRINTERS

The present invention relates to a three-dimensional printer which drives two filaments with one motor.

One of the important problems in the feeding mechanisms in three-dimensional printers is the need for stepper motors as many as the number of filaments in order to drive more than one filament. In the state of the art, a separate stepper motor is used to drive each filament, which in turn much increases the dimensions and the weight of the feeding mechanism.

In the state of the United States Patent No. US8827684, a three-dimensional printer is disclosed, comprising stepper motors as many as the number of filaments to drive a plurality of filaments, wherein common fixtures are used to minimize the dimensions thereof.

Another state of the art embodiment is disclosed in United States Patent Application No. US2012189729. In the three-dimensional printer disclosed in this document, there are two stepper motors which are oppositely placed, a filament crushing gear and a ball bearing on the shaft of the motors. By oppositely placing the motors, the filament crushing gear of one motor drives the filament using the ball bearing of the other motor, thus two filaments can be driven with two stepper motors in a small space.

In the state of the United States Patent Application No. US2208213419, a three-dimensional printer is disclosed, comprising a mechanism which is installed in the direction of rotation of the motor driving the solid material, which compresses the material while rotating in the pushing direction and releases the material while rotating in the opposite direction.

Another state of the art embodiment is disclosed in United States Patent Application No. US2007228590. In this document, a three-dimensional printer is disclosed, comprising a mechanism which moves between the first and second positions so as to form two production lines and which drives the filament with the motion of the stepper motor after switching between the extruder positions.

The aim of the present invention is the realization of a three-dimensional printer which drives a plurality of filaments.

The three-dimensional printer realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a motor; a motor shaft; two unidirectional ball bearings which are mounted to said motor shaft; two drive gears which are coaxially mounted onto the two ball bearings; and two guiding members which extend parallel to the motor shaft next to each drive gear, wherein the filament is inserted between the drive gear and the guiding member. Thus, at least two filaments can be driven with a single motor by driving the filament related to the rotational direction of the motor. In fact, as by means of the present invention the number of motors is half of the number of filaments driven, the volume and mass of the feeding mechanism is reduced. The dimensions of the feeding mechanism create unused regions in the production volume, and since the volume of the feeding mechanism decreases, the efficient production volume increases. Moreover, as the mass of the feeding mechanism decreases, the moment of inertia also decreases, thus ensuring a more stable and precise production process.

The distance between the drive gears and the guiding member can be adjusted. Thus, filaments with different diameters can be driven.

In the preferred embodiment of the present invention, the three-dimensional printer comprises a first ball bearing; a first drive gear which is mounted onto the first ball bearing; a second ball bearing which is mounted to the same motor shaft coaxially with the first ball bearing; a second drive gear which is mounted onto the second ball bearing; and a first and a second guiding member which are positioned right and left so as to align with the first gear and the second gear, wherein the filaments coming from the first and second feeding paths remain therebetween so as to be driven.

In the preferred embodiment of the present invention, the motor is a stepper motor.

In an embodiment of the present invention, the motor shaft has a D-shaped cross-section.

Since two filaments can be driven by means of the present invention, the support structure can be easily discarded in pieces produced by selecting production material and water-soluble support filament. Thus, the need for cleaning the support is eliminated, and the supports do not leave any traces on the main piece.

By means of the present invention, the volume and mass of the mechanism driving a plurality of filaments is prevented from increasing, thus providing a mechanism with less volume and increasing the efficient production area. Moreover, since its low mass reduces the moment of inertia, it also reduces the reaction force which would act on the axis motors during the change of direction. Thus, a more stable and precise production is performed.

A three-dimensional printer realized in order to attain the aim of the present invention is illustrated in the attached figure, where:

Figure 1 – is the perspective view of the feeding mechanism of a three-dimensional printer.

The elements illustrated in the figures are numbered as follows:

Three-dimensional printer
Motor
Motor shaft
Feeding mechanism
First ball bearing
Second ball bearing
First drive gear
Second drive gear
First guiding member
Second guiding member
First guide shaft
Second guide shaft
First feeding line
Second feeding line
Filament

The three-dimensional printer (1) comprises a motor (2); a motor shaft (3); and a feeding mechanism (4) having two unidirectional ball bearings (5 and 6) which are mounted to said motor shaft (3) one behind the other, two drive gears (7 and 8) which are coaxially mounted onto the two ball bearings (5 and 6), and two guiding members (9 and 10) which extend parallel to the motor shaft (3) next to each drive gear (7 and 8), wherein the filament (15) is inserted between the drive gear (7 and 8) and the guiding member (9 and 10). Thus, by using freewheel clutch principle of the unidirectional ball bearing (5 and 6), a pair of filaments (15) are driven with a single motor (2).

In the three-dimensional printer (1), the filament (15) enters between the drive gear (7 and 8) and the guiding member (9 and 10), and after this step, the filament (15) is squeezed between the driving gear (7 and 8) and the guiding member (9 and 10) with the effect of the rotation. The drive gear (7 and 8) leaves marks on the filament (15) which is squeezed so as to form pressing surfaces. Said pressing surfaces prevent the filament (15) from sliding. Moreover, since the distance between the gears (7 and 8) and the guiding members (9 and 10) can be adjusted, a filament (15) with desired thickness can be driven.

While rotating in one direction, the unidirectional ball bearing (5 and 6) functions as a ball bearing, but in the other direction, functions as a clutch. Thus, different filaments (15) can be driven in both directions by separating in the rotational direction of the motor (2). For example, the unidirectional ball bearing (6) in front, functioning as a clutch clockwise, drives the filament (15) downwards, which is squeezed between the drive gear (7 and 8) and the guiding member (9 and 10). Meanwhile, the ball bearing (5) at the rear does not move.

In the preferred embodiment of the three-dimensional printer (1) of the present invention, the ball bearings (5 and 6) are snap-fitted onto the motor shaft (3) one behind the other. In this embodiment, the three-dimensional printer (1) further comprises a motor shaft (3) with D-shaped profile. After being snap-fitted onto the drive gear (7 and 8), the unidirectional ball bearing (5 and 6) is mounted onto the motor shaft (3) with D-shaped profile.

In the preferred embodiment of the present invention, the feeding mechanism (4) comprises a first ball bearing (5) which is snap-fitted onto the motor shaft (3) and a second ball bearing (6) snap-fitted in the front thereof; a first drive gear (7) which is coaxially mounted onto the first ball bearing (5); a second drive gear (8) which is coaxially mounted to the second ball bearing (6); a first guiding member (9) which is positioned as aligned with the first drive gear (7) so as to be spaced apart from the first drive gear (7) at a certain distance; and a second guiding member (10) which is positioned as aligned with the second drive gear (8) so as to be spaced apart from the first drive gear (8) at a certain distance. In the preferred embodiment of the present invention, the feeding mechanism (4) comprises a first guide shaft (11) which is positioned parallel to the motor shaft (3) and whereon the first guiding member (9) is mounted so as to rotate therearound, and a second guide shaft (12) which is positioned parallel to the motor shaft (3) and whereon the second guiding member (10) is mounted so as to rotate therearound (Figure 1).

In the preferred embodiment of the present invention, the feeding mechanism (4) further increases a first feeding path (13) through which the filament (15) passes and moves towards the feeding mechanism (4) so as to enter between the first drive gear (7) and the first guiding member (9), and a second feeding path (14) which enables the filament (15) to enter between the second drive gear (8) and the second guiding member (10).

In the three-dimensional printer (1), the feeding mechanism (4) operates as follows: The second ball bearing (6) functioning as a clutch clockwise drives downwards the filament (15), which is squeezed between the second drive gear (8) and the second guiding member (10), through the second feeding path (14). Meanwhile, the ball bearing (5) does not move. When the rotational direction of the motor (2) changes, the first ball bearing (5) functioning a clutch counterclockwise starts to rotate with the first drive gear (7) thereon. Meanwhile, the filament (15) between the first drive gear (7) and the first guiding member (9) is driven downwards through the first feeding path (13). During this process, the second ball bearing (6) does not move.

The present invention drives two filaments (15) with a single motor (2) unlike patents disclosing similar embodiments. Generally, in embodiments where a plurality of filaments (15) are driven, one motor (2) is used for each filament (15) being driven. By means of the present invention, the feeding mechanism (4) uses only one motor (2) for the intake of both filaments (15), and thus the volume and mass of the feeding mechanism (4) are decreased. This decrease in volume increases the effective production volume. Since the decrease in mass decreases the inertia force, the reaction forces acting on the axis motors (2) during the change of direction of the feeding mechanism (4) are reduced, ensuring a more stable and precise production process.

Claims

A three-dimensional printer (1) comprising a motor (2) and a motor shaft (3); characterized by a feeding mechanism (4) having two unidirectional ball bearings (5 and 6) which are mounted to said motor shaft (3) one behind the other, two drive gears (7 and 8) which are coaxially mounted onto the two ball bearings (5 and 6), and two guiding members (9 and 10) which extend parallel to the motor shaft (3) next to each drive gear (7 and 8), wherein the filament (15) is inserted between the drive gear (7 and 8) and the guiding member (9 and 10).
A three-dimensional printer (1) as in Claim 1, characterized by the feeding mechanism (4) comprising the two unidirectional ball bearings (5 and 6) which function as a ball bearing while rotating in one direction and as a clutch while rotating in the other direction.
A three-dimensional printer (1) as in Claim 1 or 2, characterized by the feeding mechanism (4) comprising the two ball bearings (5 and 6) which are snap-fitted onto the motor shaft (3) one behind the other.
A three-dimensional printer (1) as in Claim 1, characterized by a motor shaft (3) with a D-shaped profile.
A three-dimensional printer (1) as in Claim 1, characterized by the feeding mechanism (4) comprising a first ball bearing (5) which is snap-fitted onto the motor shaft (3) and a second ball bearing (6) snap-fitted in the front thereof; a first drive gear (7) which is coaxially mounted onto the first ball bearing (5); a second drive gear (8) which is coaxially mounted to the second ball bearing (6); a first guiding member (9) which is positioned as aligned with the first drive gear (7) so as to be spaced apart from the first drive gear (7) at a certain distance; and a second guiding member (10) which is positioned as aligned with the second drive gear (8) so as to be spaced apart from the first drive gear (8) at a certain distance.
A three-dimensional printer (1) as in Claim 5, characterized by the feeding mechanism (4) comprising a first guide shaft (11) which is positioned parallel to the motor shaft (3) and whereon the first guiding member (9) is mounted so as to rotate therearound, and a second guide shaft (12) which is positioned parallel to the motor shaft (3) and whereon the second guiding member (10) is mounted so as to rotate therearound.
A three-dimensional printer (1) as in Claim 5 and 6, characterized by the feeding mechanism (4) comprising a first feeding path (13) through which the filament (15) passes and moves towards the feeding mechanism (4) so as to enter between the first drive gear (7) and the first guiding member (9), and a second feeding path (14) which enables the filament (15) to enter between the second drive gear (8) and the second guiding member (10).