Transmission gearbox with a belt drive

Abstract

Transmission gear (1), comprising a belt drive, which has at least two transmission shafts connected by a drive belt and a belt tensioning device, characterized by a power measurement device for recording the mechanical power transmitted through the transmission gear and a control device connected to the belt tensioning device for adjusting the belt tension to the mechanical power transmitted through the transmission gear.

Description

[0001] The invention relates to a transmission gear with belt drive according to claim 1.

[0002] In belt drives, the drive belts must be highly tensioned when transmitting high power, such as in wind turbines, so that the resulting forces and torques can be transmitted without slippage. However, high drive belt tension negatively impacts their service life.

[0003] It is therefore an object of the invention to provide a transmission with a belt drive, the drive belts of which have an increased service life despite high power transmission.

[0004] This problem is solved by the features of claim 1.

[0005] As a rule, transmission gears do not always need to transmit maximum power. This allows the drive belt tension to be adjusted via a control device according to the power currently being transmitted. In partial load ranges, e.g., when used in a wind turbine according to EP 3 784 925 B2 in light winds, the belt tension can be reduced. Only in the full load range, in wind turbines in strong winds, is the belt tension increased. By adjusting the belt tension to the power being transmitted, the drive belts are protected and thus have an extended service life.

[0006] The subclaims relate to advantageous embodiments of the invention.

[0007] Preferably, the belt tension is adjusted hydraulically, and all drive belts are subjected to the same hydraulic pressure. An analysis of data from a wind turbine operated by the Munich municipal utility company shows that it generated electricity for 6,388 hours. However, 88% of the electricity production was generated in only 2,000 operating hours. Roughly speaking, therefore, the drive belts only need to be subjected to high belt tension for 22% of the wind turbine's operating time; a lower belt tension is sufficient for 78% of the operating time. This clearly shows that a performance-dependent adjustment of the belt tension can significantly reduce the load on the drive belts.

[0008] Further details, features and advantages of the invention will become apparent from the following description of an exemplary embodiment.

[0009] The Fig. 1 to 5 show a hybrid transmission according to the Fig. 1 and Fig. 2 with associated description of EP 3 784 925 B2, wherein the hybrid transmission in the Fig. 1 to 5 without a third gear stage, but with a hydraulically operated belt tensioning device with linear displacement means (drawn in green) and hydraulic drive (drawn in grey). QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 784 925 B2 [0005, 0009]

Claims

[1] Transmission gear (1), with a belt transmission having at least two transmission shafts connected via a drive belt and a belt tensioning device, characterized by a power detection device for detecting the mechanical power transmitted by the transmission gear and a control device connected to the belt tensioning device for adjusting the belt tension to the mechanical power transmitted by the transmission gear. [2] Transmission gear according to claim 1, characterized by that the belt tensioning device comprises a linear displacement means for linearly displacing the axes of rotation of at least two transmission shafts, which are connected to one another via a drive belt, relative to one another. [3] Transmission gear according to claim 2, characterized bythat the linear displacement means only moves one of the axes of rotation of the two transmission shafts, which are connected to each other via a drive belt. [4] Transmission gear according to one of the preceding claims, characterized by that the linear displacement device is a hydraulically driven linear displacement device. [5] Transmission gear according to one of the preceding claims, characterized by that the transmission gear is a hybrid transmission with gear shafts connected via gears and drive belts. [6] Transmission gear according to claim 5, characterized by that the hybrid transmission includes the following components: a sun gear (2) mounted on a slowly rotating gear shaft (4), a plurality of planetary units (6), each comprising a planetary gear (8) and at least one planetary shaft gear (10), which are mounted side by side on a planetary shaft (12), wherein the diameter of the planetary shaft wheels (10) is larger than the diameter of the planetary gear wheels (8), wherein the planetary gears (8) are in engagement with the sun gear (2), and wherein the diameter of the sun gear (2) is larger than the diameter of the planetary shaft gears (10), at least one high-speed unit (14) with a fast-rotating gear shaft (18) on which at least two high-speed shaft gears (16) are mounted, wherein the diameter of the high-speed shaft gears (16) is smaller than the diameter of the planetary shaft gears (10), and a plurality of drive belts (20), each of which engages with a planetary shaft wheel (10) and a high-speed shaft wheel (16), wherein the slowly rotating gear shaft (4) and the planetary shafts (12) are arranged parallel and at a distance from each other, and wherein on the rapidly rotating gear shaft (18) of the at least one high-speed unit (14) two high-speed shaft wheels (16) are mounted at a distance from one another, which are each in engagement with the drive belts (20) of different planetary units (6). [7] Transmission gear (1) according to claim 6, characterized by that in some of the planetary units (6) the respective planetary shaft gear (10) is arranged on one side of the sun gear (2) and in the other part of the planetary units (6) the respective planetary shaft gear (10) is arranged on the other side of the sun gear (2). [8] Transmission gear (1) according to claim 6 or 7, characterized by that half of the planetary shaft gears (10) are arranged on one side and the other half of the planetary shaft gears (10) are arranged on the other side of the sun gear (2). [9] Transmission gear (1) according to one of the preceding claims 6 to 8, characterized by , that the planetary units (6) each comprise a first and a second planetary shaft gear (10) mounted on the planetary shaft (12), and that the planetary gear (8) is mounted between the two planetary shaft gears (10). [10] Transmission gear (1) according to one of the preceding claims 6 to 9, characterized by that the at least one fast-rotating gear shaft (18), the planetary shafts (12) and the slow-rotating gear shaft (4) are mounted in a common frame or carrier (22). [11] Transmission gear according to one of the preceding claims, characterized by that all drive belts (20) are the same length.

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