SPINNING ROTER ARRANGEMENT FOR A ROTOR SPINNING MACHINE

Description

[0001] The invention relates to a spinning rotor assembly for a rotor spinning machine as well as a rotor spinning machine.

[0002] Rotor spinning machines are widely used for processing fiber material or roving into workable yarn or thread by a spinning rotor of a spinning rotor assembly. Such spinning rotor assemblies comprising the spinning rotor connected to a rotor shaft as well as at least one bearing unit are typically used in spinning machines, in particular in open-end rotor spinning machines.

[0003] A rotor spinning machine with a spinning rotor assembly with the features of the preamble portion of claim 1 is known from document EP 3 489 397 A1.

[0004] Further designs of a spinning rotor assembly are also known from the documents DE 26 22 628 A1, WO 2006 / 007887 A1, DE 88 08 476 U1 and GB 1 370 838 A. The spinning rotor assemblies known from these documents are designed such that a pivoting axle is provided at an end side of the brake lever without dividing the brake lever into an actuation side and a braking side.

[0005] Additionally, a spinning rotor assembly is known from document CN 101 363 151 B. This document discloses a brake lever with a pivot axle arranged in parallel to the longitudinal axis of the rotor shaft and perpendicular to the pivoting axis of the housing. The brake lever is thereby built by a U-shaped profile element having from a view in longitudinal direction of the spinning rotor shaft a triangle shape. The pivot axle formed by a bolt is arranged at a distance from the spinning rotor shaft and extends in parallel to the longitudinal extension direction of the spinning rotor shaft.

[0006] Such open-end rotor spinning machines are operated at speeds of 100,000 rpm and above. During the operation of the rotor spinning machine, the spinning rotor is typically arranged in a housing to protect an operator from being injured and to avoid any contact of the rotating spinning rotor with other parts of the rotor spinning machine or with materials in the surrounding environment. Accordingly, it is particularly important to quickly stop the rotation of the spinning rotor when the housing is opened. Additionally, opening the housing including a movement of the fast-rotating spinning rotor would lead to huge forces acting upon the spinning rotor assembly and in particular on the at least one bearing unit rotatably mounting the spinning rotor shaft to the housing, which might result in a wear or even a damaging of the spinning rotor assembly.

[0007] It may be considered a first object of the present invention to propose a spinning rotor assembly of a rotor spinning machine which can be quickly stopped when a housing provided for protecting the spinning rotor is opened.

[0008] It may be considered another object of the present invention to propose a spinning rotor assembly of a rotor spinning machine which can be securely operated, in particular to avoid an injury of a user operating the rotor spinning machine and / or to prevent materials in the environment of the rotor spinning machine from being captured by or entangled in the fast-rotating spinning rotor.

[0009] A further objective of the invention may also be to propose a rotor spinning machine which automatically stops the fast-rotating spinning rotor quickly when the spinning rotor in operation becomes accessible and in particular when a housing is opened or pivoted.

[0010] It might be finally considered an objective of the present invention to propose a spinning rotor assembly of a rotor spinning machine which automatically prevents damaging the bearing units of the spinning rotor assembly due to a movement and in particular a tilting of the fast-rotating spinning rotor.

[0011] These and further objectives may be achieved by a spinning rotor assembly according to claim 1 or a rotor spinning machine according to claim 12. Dependent claims refer to preferred embodiments of the invention.

[0012] Preferably, the spinning rotor assembly of the rotor spinning machine is a part of a spinbox of the rotor spinning machine, wherein most preferably the rotor spinning machine comprises several, in particular identical spinboxes.

[0013] A rotor brake which at least automatically engages when the rotor assembly comprising the spinning rotor is moved from a first to a second position advantageously allows a safe operation of the rotor spinning machine. Additionally, the rotor brake can be used to stop the spinning rotor at a defined time and / or in a defined position, in particular in a defined rotational position of the rotor assembly. Additionally, the rotor brake favorably protects the bearing units from being damaged due to high forces resulting from movement, in particular tilting or pivoting the fast-rotating spinning rotor by an operator. The rotor brake might also be used to adjust the forces acting upon the bearing units according to specifications of the bearings. Finally, the rotor brake might advantageously be used to abruptly stop the spinning rotor to clean the spinning rotor from dust of the fiber material or roving supplied to the spinning rotor and / or of the yarn or thread produced in the spinning rotor.

[0014] The rotor spinning machine might be any machine for processing fiber material or roving into workable yarn or thread by a spinning rotor. The rotor spinning machine might comprise only one single rotor, in particular arranged in a spinbox. Preferably, the spinning machine comprises several spinning rotors and in particular several identical spinboxes each comprising one spinning rotor. The rotor spinning machine can comprise further optional components, in particular provided for processing the fiber material or the roving before spinning and / or the yarn or the thread after spinning.

[0015] To be able to process the fiber material or the roving, a spinning rotor assembly is provided, in particular to allow for a rotation of the spinning rotor with high rotational speed. The spinning rotor assembly is preferably a part of a spinbox of a rotor spinning machine. The spinning rotor assembly at least comprises a spinning rotor, a spinning rotor shaft and at least one bearing unit as well as a housing at least for protecting the spinning rotor. The rotor assembly might also comprise further parts such as a belt roller for transmission of the spinning rotor shaft by a drive belt or at least one resilient mounting element for damping vibrations between the bearing unit and the housing.

[0016] The spinning rotor of the rotor spinning machine is a component or an assembly for processing fiber material or roving into workable yarn or thread and is in particular a spinning rotor of an open-end spinning machine. Preferably the spinning rotor is a rotor cup, which is more preferably build as one part and / or out of metal. Advantageously, the spinning rotor is a rotational-symmetric component to avoid imbalances during rotation. Such a spinning rotor might spin with more than 100,000 revolutions per minute and even up to 200,000 revolutions per minute during regular operation. Accordingly, even small imbalances would lead to large forces acting upon the rotating parts which have to be designed and / or built to withstand the forces of the regular operation.

[0017] The spinning rotor shaft might be built as one component or as an assembly of several single components. Preferably, the spinning rotor shaft is built as one single part, extending from one end of the rotor assembly to the other. The spinning rotor shaft is provided for mounting the spinning rotor rotatably via at least one bearing unit to the housing. Advantageously, the spinning rotor shaft is a rotational-symmetric component to avoid imbalances during rotation. The spinning rotor shaft might have a constant diameter along its entire length. Preferably, the diameter in the middle of the spinning rotor shaft and / or in a section between at least two, preferably between all bearing units is larger than at the end sections of the spinning rotor shaft, in particular the end for mounting the spinning rotor.

[0018] At least one bearing unit is provided for rotatably mounting the spinning rotor shaft to a housing of the spinning rotor assembly and / or of a spinbox and / or of the rotor spinning machine. Preferably, at least two bearing units are arranged on the spinning rotor shaft. More preferably, all bearing units are identical to each other and / or are arranged at a distance to one another along the spinning rotor shaft. The bearing unit may comprise and in particular be any kind of bearing; preferably however, the bearing units are each a rolling bearing.

[0019] According to the invention, the spinning rotor assembly is movable between a first and a second position. Although this movement might also be a linear movement or comprise a lateral component, the movement is only a pivoting motion, most preferably with a single pivoting axis. Preferentially, the axis of the pivoting movement of the spinning rotor assembly is arranged perpendicular to the axis of rotation of the spinning rotor and / or of the spinning rotor shaft. Generally, the spinning rotor assembly may be movably mounted in the spinbox and / or relative to another part, unit or assembly of the spinbox or of the rotor spinning machine. Advantageously, the rotor assembly is movable and in particular pivotable relative to a girder, to a part of a housing and / or to a mounting frame for setting up and / or positioning a rotor spinning machine including the spinning rotor assembly to the ground.

[0020] Accordingly, the housing of the spinning rotor assembly comprises two parts pivotably mounted to one another. The first part of the housing is fixed to the at least one bearing unit, preferably to all bearing units of the rotor assembly, and can be provided to be pivotally mounted relative to the rest of the rotor spinning machine or to the ground the rotor spinning machine is positioned on. The second part of the housing is arranged pivotally relative to the spinning rotor.

[0021] According to the invention, a rotor brake is pivotally mounted to the housing, in particular a first part of the housing. The rotor brake is provided to efficiently brake the spinning rotor. Preferably, the rotor brake mechanically interacts with a part of the spinning rotor shaft to brake the spinning rotor. More preferably the rotor brake interacts with an end of the spinning rotor shaft and most preferably the rotor brake interacts with a part of the spinning rotor shaft provided to be driven by a drive belt and / or with a belt drive roller arranged at an end of the spinning rotor shaft.

[0022] Also according to the invention, the rotor brake is mounted to the housing so that the rotor brake automatically engages when the spinning rotor assembly and / or accordingly also the housing of the spinning rotor assembly is moved from the first to the second position. Preferably, the engagement of the rotor brake is only driven by mechanical interaction of the rotor brake and further parts of the rotor spinning machine, in particular the spinning rotor assembly, the housing of the spinning rotor assembly and / or parts of the rotor spinning machine for firmly positioning the rotor spinning machine to the ground.

[0023] The first position is an operational position of the spinning rotor and can be a position where the spinning rotor assembly including the spinning rotor is driven to produce thread or yarn. In the first position, the first and the second part of the housing are in contact to form a closed housing. Accordingly, the second position is a position where the spinning rotor is accessible and can be a position where the spinning rotor is not in operation. In the second position, the first and the second part of the housing are not in contact to provide an opening to access the spinning rotor.

[0024] Accordingly, the spinning rotor assembly is pivotal about a pivoting joint between a first, closed position for operation of the spinning rotor and a second, open position, where the spinning rotor is accessible. Further the rotor brake is built to automatically engage when the spinning rotor assembly is moved into the open position and / or to automatically release again when the spinning rotor assembly is moved into or reaches the closed position. Additionally preferentially, the spinning rotor assembly is movably, in particular pivotally mounted so that when moving into the second, open position, the end of the spinning rotor shaft or a belt roller, in particular arranged at an end of the spinning rotor shaft, is moved away from a drive belt and therefore the drive is disengaged and / or the connection to the actuator is interrupted. Most preferably, the disengagement from the drive belt and the engagement of the rotor brake, in particular a mechanical engagement of the rotor brake to the spinning rotor shaft, occur simultaneously or at least directly consecutively.

[0025] It is also preferred that the rotor brake is built to be permanently engaged in the second, open position of the spinning rotor assembly and / or as long as the spinning rotor assembly is not in the closed position to ensure the safety of an operator of the rotor spinning machine. Such an embodiment of the rotor brake advantageously cannot be released as long as the spinning rotor is accessible. Preferably, the rotor brake is mechanically built to be engaged in the open position of the spinning rotor assembly. Even more preferably it is mechanically impossible to release the rotor brake as long as the spinning rotor assembly is not in the closed position. Hence, an operating error of an operator is impossible in such an embodiment.

[0026] In a further development of the spinning rotor assembly according to the invention, the rotor brake is built entirely from mechanical parts and / or without an electric control and / or without electric actuators such as a motor or the like. Accordingly, the rotor brake is always functional and is in particular not dependent of an electrical power supply. It is further preferred that the rotor brake does not comprise any hydraulic or pneumatic components, at least for engaging the motor brake. Hence, the rotor brake is preferably always functional. According to the invention, the rotor brake is driven at least towards an engaged position solely by spring force.

[0027] Generally, any surface or part of the rotor brake might interact with the spinning rotor shaft mechanically during the engagement of the rotor brake. However, it is preferred that the rotor brake comprises a braking surface which is brought in contact by spring force and in particular pressed by spring force against the spinning rotor shaft or against a belt roller preferably fixed to an end of the spinning rotor shaft when the rotor brake is engaged and / or when the spinning rotor assembly is moved out of the first, closed position. Preferentially, the braking surface is provided for a direct and / or a mechanical interaction with a surface of the spinning rotor shaft or a belt roller. More preferably the shape of the braking surface is adapted to the shape of the section of the spinning rotor shaft interacting with the braking surface. Most preferably, the braking surface has the same curvature or radius as the spinning rotor shaft or as the belt roller. Advantageously, the braking surface is shaped to provide a large contact area to the spinning rotor shaft.

[0028] The rotor brake and in particular the braking surface of the rotor brake might engage the surface of the spinning rotor shaft or the belt roller in any position. However, it is preferred that the rotor brake is pressed against the surface of the spinning rotor shaft or of a belt roller opposite to the side of the spinning rotor shaft or the belt roller provided to be brought in contact with a drive belt so that the drive belt cannot get in contact with the rotor brake which might impede the braking effect. Also, arranging the drive belt and the rotor brake on opposing sides of the spinning rotor shaft, it is easily possible to pivot the spinning rotor shaft away from the drive belt and at the same time towards the rotor brake or vice versa. Accordingly, an even faster engagement of the rotor brake and disengagement from the drive belt is possible and / or an simultaneous contact of the spinning rotor shaft with the drive belt and the rotor brake is easily avoided.

[0029] According to the invention, the rotor brake comprises a brake lever which is pivotally mounted via a pivot axle to the housing, wherein on one side, in particular on one end of the brake lever the braking surface is located and on the other side, in particular on the other end of the brake lever a spring element is provided. Preferably the spring element is arranged between the brake lever and the housing to apply force to the brake lever towards an engaged position, where the rotor brake is engaged and / or where the braking surface is brought in contact with the spinning rotor shaft or a belt roller. The spring element preferentially preloads the brake lever towards the position of a brake engagement. The spring element might be attached to the brake lever in any possible way. It is preferred that the spring element is in particular supported at one end against the brake lever and / or at the other end against the housing, in particular the first part of the housing.

[0030] The brake lever might have any shape and size. According to the invention, the brake lever is divided into two sides by the pivot axle, the first side being an actuation side and the second side being a braking side. On the braking side the braking surface is provided and on the actuation side at least the spring element is arranged. It is further preferred that the lever has an L-shape and / or two sections which are arranged approximately perpendicular to one another. More preferably, the pivot axle is arranged on the longer side of the L-shaped lever, in particular approximately in the middle of this longer side. Also preferably, the short side of the L-shaped lever is pushed by the housing when the spinning rotor assembly is moved from the first to the second position leading to an engagement of the rotor brake. Advantageously, the longer side of the L-shaped lever and / or the side of the lever comprising the braking surface is arranged in parallel to the spinning rotor shaft, at least in an engaged position of the rotor brake. According to the invention, the pivot axle of the brake lever and the pivoting axis of the two parts of the housing are arranged in parallel and can be at a distance to one another.

[0031] To improve the longevity and to facilitate the maintenance of the spinning rotor assembly, a brake pad is preferably removably and / or replaceably mounted on an end of the brake lever to provide the braking surface. Such an embodiment advantageously allows to easily replace the part of the rotor brake with the braking surface. The braking pad might be made of any material and might have any shape. Preferably, the braking pad provides the entire braking surface. Also preferably, the brake pad is made of a material which is softer than the surface of the spinning rotor shaft or of the drive roller the brake pad is interacting with when the rotor brake is engaged. Most preferably, the brake pad is made out of a polymer. Although the brake pad might also be an integral part of the brake lever, preferably the brake pad is a separate part and can be fixed to brake lever. Most preferably, a brake pad holder is provided on the braking side of the lever to receive and hold the braking pad firmly in position.

[0032] According to a preferential embodiment of the spinning rotor assembly, a contact element is arranged on the brake lever to be pressed against a surface of a non-pivotable girder of the rotor spinning machine in the closed position of the spinning rotor assembly to hold the rotor brake in an unengaged position, wherein the contact element and the surface of the girder loose contact when the brake lever is pivoted together with the spinning rotor assembly from the first, closed position into the second, open position so that the rotor brake is automatically engaged. It is further preferred that the brake lever and in particular the contact element looses contact to the girder, when the spinning rotor assembly is moved into the second, open position, and accordingly the rotor brake is engaged. Preferentially, the contact element pressed against a contact point on the surface of the girder stops the rotor brake and in particular the braking surface from contacting the spinning rotor shaft or the belt roller in the closed position of the spinning rotor assembly. It is also preferred that the contact element is arranged on an opposite side of the brake lever to the brake surface and / or on the same side as the spring element. Advantageously, the contact element is aligned perpendicular to the braking surface. The girder may be any part of the frame or of a housing of the spinbox or of the rotor spinning machine which is arranged non-pivotable relative to the ground the rotor spinning machine is positioned on.

[0033] To be able to adjust the position and / or the timing of the brake engagement when moving the spinning rotor assembly from the first to the second position, according to a preferred embodiment of the spinning rotor assembly the contact element is arranged adjustably, in particular longitudinally adjustable by a threaded connection to the brake lever. Such an arrangement allows to adjust the engagement of the rotor brake dependent on the pivoting angle of the spinning rotor assembly and / or to adjust the distance of the disengaged brake surface from the spinning rotor shaft or of the belt roller in the closed position.

[0034] It is additionally preferred that a stop element is arranged on the housing of the spinning rotor assembly or on the girder to provide a stop point for the housing tilted into the open position. Preferably, the stop point is located on a part of the girder opposite to the contact point on the girder. Accordingly, the housing of the spinning rotor assembly is preferably arranged in an area between the stop point and the contact point. Most preferably, the stop point and the contact point are arranged on one single girder and / or both points are arranged in one plane.

[0035] In an advantageous embodiment of the spinning rotor assembly, the spring element is adjustably mounted to the brake lever to adjust the force, the braking surface of the brake lever or the brake pad is applying to the surface of the spinning rotor shaft or of the belt roller. More preferably, the spring element is longitudinally adjustable by a threaded connection allowing a continuous adjustment.

[0036] Finally, it is also preferred that a control element is provided to allow an engagement of the rotor brake in the closed position of the spinning rotor assembly additional to the automatic rotor brake engagement when moving the spinning rotor assembly out of the closed and / or into the opened position, which also allows to brake the spinning rotor in the first position of the spinning rotor assembly, for example to avoid strong forces from action on the at least one bearing unit, to clean the spinning rotor by strongly braking or to shut down the spinning machine as fast as possible. It is especially preferred that additional to the automatic engagement mode of the rotor brake a manual mode is provided which allows an operator or a control unit of the rotor spinning machine to brake the spinning rotor, especially also in the first position of the spinning rotor assembly.

[0037] These and other aspects of the invention will be apparent from and elucidated with reference to an embodiment described hereinafter. Fig. 1shows a perspective view of a rotor assembly including a spinning rotor, a housing and a rotor brake; and Fig. 2shows a perspective, partially transparent view of the rotor assembly shown in fig-ure 1, and Fig. 3shows a sectional view of the rotor brake of the rotor assembly shown in figure 1.

[0038] A spinning rotor assembly 1 as shown in figure 1 comprises a spinning rotor 2 mounted to a spinning rotor shaft 3. The spinning rotor 2 is arranged in a housing 4 to protect an operator of an open-end rotor spinning machine comprising several spinboxes each with one spinning rotor assembly 1. To rotatably mount the spinning rotor 2 to the housing 4, the spinning rotor shaft 3 is arranged to the housing via two bearing units 5 (see figure 2).

[0039] To access the spinning rotor 2, the spinning rotor assembly 1 can be pivoted from a first closed position for spinning to a second, open position. Accordingly, the housing 4 comprises pivoting joints 7 to provide means for mounting the spinning rotor assembly 1 pivotally about a pivoting axis.

[0040] However, before an operator can access the spinning rotor 2 after pivoting the spinning rotor assembly 1 into the open position, the spinning rotor 2 has to be braked from a rotational speed of over 100,000 rpm during operation to a complete halt. Accordingly, a rotor brake 6 is provided. The rotor brake 6 comprises a brake lever 11 pivotably mounted with a pivot axle 12 to the housing 4 of the spinning rotor assembly 1.

[0041] The pivot axle 12 of the brake lever 11 is arranged parallel to the pivoting joint 7 on the housing 4 of the spinning rotor assembly 1 and perpendicular to the rotational axis of the spinning rotor shaft 3. A spring element 13 is arranged between the brake lever 11 and the housing 4 on one side of the pivot axle 12. The spring element 13 is preloading the brake lever 11 towards an engaged position of the rotor brake 6. On the opposite side of the pivot axle 12 of the brake lever 11, a brake pad 14 is arranged at an end of the brake lever 11, wherein the brake pad 14 comprises a braking surface 8 to be brought in direct contact to a surface 9 of the spinning rotor shaft 3 (see figure 3). Accordingly, the rotor brake 6 is operated by a mechanical contact and in particular by friction between the surface of the brake pad 14 and the surface 9 of the spinning rotor shaft 3.

[0042] The brake pad 14 engages the surface 9 of the spinning rotor shaft 3 in a position directly opposite to the position where a surface 9 of the spinning rotor shaft 3 is driven by a drive belt 10 to accelerate and to drive the spinning rotor 2 via the spinning rotor shaft 3.

[0043] To automatically engage the rotor brake 6 when pivoting the spinning rotor assembly 1 into the second, open position and to hold the rotor brake 6 in an disengaged position when the spinning rotor assembly 1 is in a first, closed position, on the side of the brake lever 11 also comprising the spring element 13 the end of the brake lever 11 is angled by 90°, wherein this angled section comprises a contact element 15. In the first, closed position of the spinning rotor assembly 1, the contact element 15 is in contact with a surface of a girder 16 of the rotor spinning machine, holding the rotor brake 6 against the force of the spring element 13 in a disengaged position. As soon as the spinning rotor assembly 1 is pivoted towards the second, open position, the contact element 15 looses the contact to the surface of the girder 16 and the spring element 13 forces the rotor brake 6 into the engaged position. Simultaneously, the spinning rotor shaft 3 looses contact to the drive belt 10.

[0044] As long as the spinning rotor assembly 1 remains in the second, open position, the rotor brake 6 stays engaged and at the same time the drive belt 10 remains contactless from the surface 9 of the spinning rotor shaft 3. Only when the spinning rotor assembly 1 is pivoted into the first, closed position again, the contact element 15 on the brake lever 11 comes into contact with the girder 16 again, releasing the brake. At the same time, the surface 9 of the spinning rotor shaft 3 comes into contact with the drive belt 10, which accelerates the spinning rotor 2 to the operation speed again.List of reference signs

[0045] 1Spinning rotor assembly 2spinning rotor 3spinning rotor shaft 4housing 5bearing unit 6rotor brake 7pivoting joint 8braking surface 9surface of spinning rotor shaft 10drive belt 11brake lever 12pivot axle 13spring element 14brake pad 15contact element 16girder

Claims

1. Spinning rotor assembly (1) for a rotor spinning machine, comprising - a spinning rotor (2) fixed to a spinning rotor shaft (3), the spinning rotor shaft (3) being rotatably mounted to a housing (4) of the spinning rotor assembly (1) by at least one bearing unit (5), wherein the housing (4) has two parts pivotably mounted to one another, wherein the first part is fixed to the at least one bearing unit (5) and the second part is arranged pivotally relative to the spinning rotor (2), - wherein the spinning rotor assembly (1) is pivotally mounted about a pivoting joint (7) between a first, closed position for operating the spinning rotor (2) and a second open position, where the spinning rotor (2) is accessible, wherein in the first position, the first and second part of the housing (4) are in contact to form a closed housing (4), wherein in the second position, the first and second part of the housing (4) are not in contact to provide an opening to access the spinning rotor (2), - wherein a rotor brake (6) for braking the spinning rotor (2) is pivotally mounted to the housing (4), so that the rotor brake (6) is built to automatically engage when the spinning rotor assembly (1) is moved from the first to the second position and to be automatically released when the spinning rotor assembly (1) reaches the closed position, - wherein the rotor brake (6) comprises a brake lever (11) pivotally mounted via a pivot axle (12) to the housing (4), wherein on one side of the brake lever (11) the braking surface (8) is located and on the other side of the brake lever (11), a spring element (13) is provided to apply force to the brake lever (11) towards an engaged position of the rotor brake (6), characterized in that the brake lever (11) is divided into two sides by the pivot axle (12), the first side being an actuation side on which the spring element (13) is arranged and the second side being a braking side on which the braking surface (8) is provided, wherein the pivot axle (12) of the brake lever (11) and the pivoting axis of the two housing parts are arranged in parallel.

2. Spinning rotor assembly according to claim 1, characterized in that the rotor brake (6) is built to be permanently engaged in the open position of the spinning rotor assembly (1).

3. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the rotor brake (6) is built entirely from mechanical parts, without an electric control and without electric actuators.

4. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the rotor brake (6) is driven towards an engaged position solely by spring force.

5. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the rotor brake (6) comprises a braking surface (8) which is pressed by spring force against the spinning rotor shaft (3) when the rotor brake (6) is engaged.

6. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the rotor brake (6) is pressed against the surface (9) of the spinning rotor shaft (3) on an opposite side to a side of the spinning rotor shaft (3) or of a belt roller to be brought in contact with a drive belt (10).

7. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that a brake pad (14) is mounted on an end of the brake lever (11) to provide the braking surface (8).

8. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that a contact element (15) is arranged on the brake lever (11) to be pressed against a surface of a non-pivotable girder (16) in the closed position of the spinning rotor assembly (1) to hold the rotor brake (6) in an unengaged position, wherein the contact element (15) and the surface of the girder (16) loose contact when the brake lever (11) is pivoted together with the spinning rotor assembly (1) from the first, closed position into the second, open position so that the rotor brake (6) is automatically engaged.

9. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the contact element (15) is arranged longitudinally adjustable by a threaded connection to the brake lever (11) to adjust the engagement of the rotor brake (6) depending on the pivoting angle of the spinning rotor assembly (1) and / or depending on the distance of the disengaged braking surface (8) from the spinning rotor shaft (3) in the closed position.

10. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that the spring element (13) is adjustably mounted to the brake lever (11) to adjust length of the spring element (13) and / or of the force the braking surface (8) is applying to the surface (9) of the spinning rotor shaft (3).

11. Spinning rotor assembly according to at least one of the proceeding claims, characterized in that a control element is provided to allow an engagement of the rotor brake (6) in the closed position of the spinning rotor assembly (1) additional to the automatic rotor brake engagement when moving the spinning rotor assembly (1) out of the closed and / or into the opened position.

12. Rotor spinning machine with a spinning rotor assembly (1) according to at least one of the claims 1 - 11.