Center spindle unit

Abstract

A central spindle unit (1) comprises a central spindle (2) provided with an inner hole (12). The central spindle unit (1) comprises a sensor tube (10), which is constructed as a hollow sleeve and is arranged in the inner hole (12) of the central spindle (2). At least one sensor (8) is arranged in the sensor tube (10) and is designed to monitor at least one bearing (6) of the central spindle (2).

Description

Technical Field

[0001] The present invention relates to the central spindle unit described in the preamble of Technical Solution 1, which comprises a stationary central spindle. Background Art

[0002] Directly driven tidal turbines can be used in the field of marine energy, and the turbines include a slowly moving ring-shaped generator. Here, a stationary central spindle (kingpin or KingPin) can be supported in a rotating housing. Such stationary central spindles can also be used in other fields such as wheel bearings of motor vehicles, planetary transmissions or wind turbines. The support is usually achieved by one or more bearings (rolling bearings or sliding bearings). To ensure the correct operation of the bearings and the rotating bearing unit, it is necessary to monitor the bearings used so that bearing failures can be detected in time and appropriate reactions can be made. For example, vibration sensors can be used to detect non-ideal vibrations of bearings that characterize defects. However, for meaningful condition monitoring, such vibration sensors must be located as close to the bearings as possible. However, due to the rotation of the bearing seat (the housing where the bearing is located), it is complicated to place the sensor on the rotating bearing seat and transmit the signal to the stationary part (such as the stationary nacelle housing). Summary of the invention

[0003] Therefore, an object of the present invention is to provide a system capable of performing good condition monitoring on a bearing.

[0004] This object is achieved by the central spindle unit described in Technical Solution 1, which includes a sensor tube arranged in the inner hole of the stationary central spindle.

[0005] Such a central spindle unit can be used, for example, for a directly driven tidal turbine comprising a slowly moving ring generator. Applications of the central spindle unit in other fields such as wheel bearings of motor vehicles, planetary gear transmissions or wind turbines are also possible. The central spindle unit comprises a stationary central spindle provided with an inner bore. The central spindle is supported in a housing by at least one bearing. In order to be able to monitor these bearings, the central spindle unit comprises a sensor tube in which at least one sensor for monitoring the at least one bearing is arranged. Here, multiple bearings can also be monitored by a single sensor. The sensor tube is constructed as a hollow sleeve and is arranged in the inner bore of the central spindle. In this way, the sensor arranged in the sensor tube (i.e. the hollow sleeve) can be easily pushed into the inner bore of the central spindle. Here, the sensor is arranged so that once the sensor tube is pushed into the central spindle, the sensor is positioned as close as possible to the at least one bearing. In a preferred case, the sensor can be a vibration sensor, of course, other sensors such as temperature sensors are also possible.

[0006] According to one embodiment, the sensor tube comprises a flange for axial attachment to the central spindle. In this way, the sensor tube can be connected and mounted on the central spindle from the outside in a relatively simple manner using the flange.

[0007] According to a further embodiment, the sensor tube comprises at least one opening. The opening is arranged on the outer surface of the hollow sleeve of the sensor tube. Here, the at least one sensor is arranged inside the sensor tube at the opening. Since the sensor is arranged in the opening, the sensor can rest directly on the central spindle. In this way, vibrations can be transmitted particularly well from the at least one bearing via the central spindle to the sensor, for example, since they are not shielded by the sensor tube.

[0008] In particular, a fixing device may be provided at the at least one opening for mounting the sensor on the sensor tube. The fixing device may be, for example, a screw. Thus, it is ensured that the sensor is located at the opening, and thus at a location where vibrations inside the sensor tube are not shielded by the sensor tube.

[0009] To facilitate the insertion of the sensor tube into the central spindle, according to a further embodiment, the sensor tube may have a smaller diameter at its axial end entering the central spindle. Since this diameter is smaller than the diameter of the rest of the sensor tube, the sensor tube can be easily inserted into the central spindle.

[0010] According to a further embodiment, the sensor tube comprises a slot extending in the axial direction. Due to the presence of the slot, the sensor tube can be compressed and inserted into the central spindle. Once the sensor tube is inside the central spindle, the sensor tube can be extended through the slot in the manner of an elastic snap ring, so that it stays in the central spindle and is embedded therein with a tight fit.

[0011] According to a further embodiment, the outer circumference of the sensor tube and / or the inner bore of the central spindle has a non-uniform ( / varying) diameter. Due to the presence of such a varying diameter at the central spindle or the sensor tube or at the same time at the central spindle and the sensor tube, an air gap can be provided between the outer circumference of the sensor and the inner bore of the central spindle, while at the same time the outer circumference of the sensor and the inner bore of the central spindle are in contact only in the area where the sensor is located. In this way it can be ensured that the sensor is in contact with the central spindle in the area where the sensor is located. This contact can, for example, be metal-to-metal contact. This contact can achieve good measuring power, since vibrations can be directly transmitted to the sensor via the contact. Furthermore, in this way the sensor can be arranged as close as possible to the at least one bearing, since it is located in the area where the sensor tube is in direct contact with the central spindle. At the same time, the air gap between the sensor tube and the central spindle ensures that the sensor tube and the central spindle are in contact with each other only in a small area. Thus, it is possible to simply insert the sensor tube into the central spindle in a low-friction manner.

[0012] The non-uniform diameter can be achieved, for example, by a gradually changing diameter or a step-like changing diameter. Such a changing diameter can be provided over the entire length or a partial section of the central spindle and / or the sensor tube. In the case of providing it in a partial section, for example, it can be provided only in the area where the sensor is located. The non-uniform diameter can also be achieved by a protruding structure provided on the central spindle and / or the sensor tube. In this case, the sensor tube and the central spindle are preferably in contact only at the protruding portion.

[0013] According to a further embodiment, the sensor can be connected to a cable. This cable can be arranged in the sensor tube and led outwardly therefrom to a generator for connection thereto to an external unit, for example a control unit. In this way, the data captured by the sensor can be sent to the external unit in a simple manner. Alternatively, these data can also be transmitted to the external unit wirelessly.

[0014] Further advantages and beneficial embodiments of the present invention will be described in the specification and claims.Here, the feature combinations described in the specification and drawings are purely exemplary, and these features can exist alone or in other combinations.

[0015] The present invention is described in detail below based on the exemplary embodiments depicted in the drawings. Here, the exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to limit the scope of protection of the present invention. The scope of protection of the present invention is limited only by the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A cross-sectional view showing the central spindle unit in the length direction;

[0017] Figure 2 show Figure 1 A partial enlarged view of the central spindle unit in FIG. 1 ; and

[0018] Figure 3 A perspective view showing the sensor tube.

[0019] Description of Reference Numerals

[0020] 1 Center spindle unit

[0021] 2 Center spindle

[0022] 4 Housing

[0023] 6 Bearings

[0024] 8 Sensors

[0025] 10 Sensor tube

[0026] 12 inner hole

[0027] 14 Opening

[0028] 16 Fixtures

[0029] 18 Flange

[0030] 20 Terminals

[0031] 22 Washer

[0032] 24 Opening

[0033] 26 First diameter of sensor tube

[0034] 28 Second diameter of sensor tube

[0035] 30 First diameter of the central spindle

[0036] 32 Second diameter of the center spindle

[0037] 34 Air gap

[0038] 36 Air gap

[0039] 38 Smaller diameter

[0040] 40 Axially extending slot DETAILED DESCRIPTION

[0041] In the following, identical or functionally equivalent components are provided with the same reference numerals.

[0042] Figure 1 A cross-section of a central spindle unit 1 in the longitudinal direction is shown. In the present case, as an example, this is a central spindle unit 1 of a tidal turbine. However, the central spindle unit 1 described here can also be used in other fields such as wheel bearings of motor vehicles, planetary gearboxes or wind turbines. The central spindle unit 1 comprises a central spindle 2 supported by bearings 6 in a housing 4. In order to be able to monitor the state of the bearings 6, sensors 8 are provided. These sensors 8 can be, for example, vibration sensors.

[0043] In order to enable the sensor 8 to be positioned as close as possible to the bearing 6, a sensor tube 10 is provided, which is arranged in an inner hole 12 of the central spindle 2. Here, the sensor 8 is arranged in the sensor tube 10 so as to be positioned as close as possible to the bearing 6. For this purpose, the sensor tube 10 is preferably provided with an opening 14, at which the sensor 8 is arranged or in the opening. Since the sensor 8 is arranged on or in the opening 14, for example, vibrations can be directly transmitted from the bearing 6 through the central spindle 2 to the sensor 8 without being shielded by the sensor tube 10. The sensor 8 can be mounted on the sensor tube 10 by means of a fixing device 16. The fixing device 16 can be, for example, a screw.

[0044] Furthermore, the fixing device 16 can also be designed as a spring element for elastically supporting the sensor 8. During the insertion of the sensor tube 10 into the central spindle 2, in this example, the sensor 8 is located in the sensor tube 10. Once the sensor tube 10 has reached its final position, the sensor 8 rests on the central spindle 2 through the opening 14, thereby forming a contact between the central spindle 2 and the sensor 8, so that, for example, vibrations can be transmitted to the sensor.

[0045] In order to install the sensor tube 10 in the central spindle 2, a flange 18 is provided on the sensor tube 10. Through the flange 18, the sensor tube 10 can be attached to the central spindle 2 in the axial direction, for example, by screwing.

[0046] In order to send the data detected by the sensor 8 to the control unit or a different unit, the sensor 8 can be connected to a cable (not shown). For this purpose, the sensor 8 can include a terminal 20 for connecting such a cable.

[0047] Figure 2 A detailed arrangement of the sensor 8 is shown. As can be seen from the figure, by means of the fixture 16, direct contact is established between the fixture 16 and the central spindle 2, and also between the sensor tube 10 and the central spindle 2. The contact can be, for example, metal-to-metal contact. Due to this direct contact, a particularly good transmission, in particular of vibrations, from the bearing 6 to the sensor 8 is ensured. A gasket 22 can be provided between the sensor 8 and the sensor tube 10, via which gasket 22 direct contact can also be achieved. The fixture 16 can further be used to adjust the sensor 8 on the surface of the central spindle 2.

[0048] In order to mount the sensor 8 in the sensor tube 10 with the fixing device 16, an opening 24 can be provided opposite the opening 14. A tool can be inserted into the sensor tube 10 through the opening 24 in order to tighten the fixing device 16.

[0049] The outer circumference of the sensor tube 10 and / or the inner hole of the central shaft 2 may have a non-uniform diameter. Due to the existence of such non-uniform diameters, air gaps 34, 36 may exist between the central shaft 2 and the sensor tube 10, and the contact between the sensor tube 10 and the central shaft 2 may only occur in the area where the sensor exists. Since the central shaft 2 and the sensor tube 10 are in contact only in this small area, the sensor tube 10 may enter the central shaft 2 in a low-friction manner.

[0050] The non-uniform diameter can be implemented as a gradually changing diameter, a step-like changing diameter and / or a protruding structure on the central spindle 2 and / or the sensor tube 10, respectively. Figure 2 In the embodiment shown, both the sensor tube 10 and the inner bore 12 of the central spindle 2 have stepped diameters. The sensor tube 10 has a stepped design with a first diameter 26 in its first section and a second diameter 28 in its second section. The central spindle 2 also has a stepped design in its inner bore with a first diameter 30 and a second diameter 32, respectively.

[0051] Figure 3 A perspective view of the sensor tube 10 is shown, which also includes the stepped diameter. The sensor tube 10 has a first diameter 26 and a second diameter 28. In addition, the sensor tube 10 has a smaller diameter 38 at its end that first enters the central spindle to facilitate insertion into the central spindle 2.

[0052] The sensor tube 10 may comprise an axially extending slit groove 40. Due to the slit groove 40, the sensor tube 10 can be compressed (crimped) together during the insertion of the sensor tube 10 into the central spindle 2. Once the sensor tube 10 is positioned inside the main central spindle 2, the sensor tube 10 can be expanded again in the manner of a snap ring and thus retained in the central spindle 2 by a tight fit.

[0053] The central spindle unit according to the invention allows the sensor to be arranged in the central spindle in a simple and uncomplicated manner. Since the sensor can be arranged in the central spindle simply by using the sensor tube, it can be ensured that at least one bearing of the central spindle can be well monitored.

Claims

1. A central spindle unit (1), comprising a central spindle (2) provided with an inner hole (12), characterized in that: The central spindle unit (1) comprises a sensor tube (10), which is constructed as a hollow sleeve and is arranged in the inner hole (12) of the central spindle (2), and at least one sensor (8) is arranged in the sensor tube (10), and the sensor (8) is configured to monitor at least one bearing (6) of the central spindle (2). The sensor tube has a cylindrical sidewall, and the sensor is disposed in an opening extending through the cylindrical sidewall of the sensor tube.

2. The central spindle unit (1) according to claim 1, characterized in that: The sensor tube (10) comprises a flange (18) for axial mounting on the central spindle (2).

3. The central spindle unit (1) according to claim 1 or 2, characterized in that: The at least one sensor (8) is arranged inside the sensor tube (10) at the opening (14).

4. The central spindle unit (1) according to claim 3, characterized in that: A fixing device (16) is provided, arranged in the at least one opening (14), for mounting the sensor (8) in the sensor tube (10).

5. The central spindle unit (1) according to claim 1 or 2, characterized in that: In order to be inserted into the inner hole (12) of the central spindle (2), the sensor tube (10) has a smaller diameter (38) at one axial end thereof.

6. The central spindle unit (1) according to claim 1 or 2, characterized in that: The sensor tube (10) comprises a slit groove (40) extending in the axial direction.

7. The central spindle unit (1) according to claim 1 or 2, characterized in that: The outer circumference of the sensor tube (10) and / or the inner bore (12) of the central spindle (2) have a non-uniform diameter.

8. The central spindle unit (1) according to claim 7, characterized in that: The outer circumference of the sensor tube (10) and / or the inner hole (12) of the central spindle (2) have a gradually changing diameter, a step-like changing diameter and / or a convex structure.

9. The central spindle unit (1) according to claim 1 or 2, characterized in that: The outer circumference of the sensor tube (10) contacts the inner hole (12) of the central spindle (2) in the area where the sensor (8) is located, and / or an air gap (34, 36) is provided between the outer circumference of the sensor tube (10) and the inner hole (12) of the central spindle (2).

10. The central spindle unit (1) according to claim 1 or 2, characterized in that: The sensor (8) is connected to a cable, which is arranged in the sensor tube (10) and can be connected to an external unit.

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