Gearbox for on-load tap changer

Abstract

This invention relates to a transmission device (G) for an on-load tap changer (S), the transmission device comprising a motor (M) having a driven shaft (ABW) and a load changer (LU) having a drive shaft (ANW), the transmission device (G) comprising: - a cam disc (KS), a drive gear (ANZ), and a roller (R) coupled to the drive gear, wherein: - the cam disc (KS) is connected to the driven shaft (ABW) without relative rotation and the driven shaft is located on the axis of rotation (RAI) of the cam disc (KS); - the drive gear (ANZ) is connected to the drive shaft (ANW) without relative rotation; - the cam disc (KS) has an inner part that can be driven out by the roller (R). The inner contour (IK) and outer contour (AK) have a first region (IKB1, AKB1) and a second region (IKB2, AKB2), respectively. The first region has a constant radius of curvature. In the second region, the distance between the corresponding contour and the axis of rotation (RA) of the cam disk (KS) varies. The roller (R) moves out of the contours (IK; AK) as the cam disk (KS) rotates, such that the roller moves out of a portion of the first region (AKB1) of the outer contour, then a portion of the second region (AKB2) of the outer contour, and then a portion of the first region (IKB1) of the inner contour.

Description

Technical Field

[0001] This invention relates to a drive mechanism for an on-load tap changer, the on-load tap changer comprising a motor having a driven shaft and a load changer having a drive shaft, and also to a corresponding on-load tap changer having a drive mechanism. Background Technology

[0002] On-load tap changers are used for uninterrupted switching between transformer winding taps. Known on-load tap changers typically consist of a selector and a load changer. The selector reactively selects the appropriate winding tap to switch to, while the load changer actually switches the previous winding tap to the selected new one. Accumulators, often referred to as energy storage devices, are typically used here to convert the continuous, slow rotational motion of a driven shaft into a rapid, skipping rotational motion of a driving shaft, driven by a motor at a constant speed. The driving shaft drives the load changer. Numerous accumulators are known that can achieve the skipping rotational motion of the driving shaft by means of a storage spring. The principle is always the same: the driven shaft, driven by a motor at a constant speed, tensions the storage spring to its maximum point, and beyond that point, the spring suddenly relaxes, thereby abruptly driving the driving shaft.

[0003] Furthermore, known accumulators typically have couplers through which the selector movement is decoupled from the load transfer switch. These couplers, also known as idling couplers, similarly cause the accumulator spring: once the switching process begins, it is no longer interrupted in the event of a fault; that is, the on-load tap changer can no longer be moved back to its initial position.

[0004] Known accumulators with springs are very complex in construction because they consist of many individual components that must work together in the correct manner. This makes known accumulators expensive and prone to error. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide an improved design for a drive mechanism in an on-load tap changer, the drive mechanism being inexpensive, enabling simpler operation of the on-load tap changer and improved safety during operation.

[0006] The task described herein is addressed by the subject matter of the independent claim. Other embodiments are described in the dependent claims.

[0007] According to the improved design, a drive mechanism for an on-load tap changer is provided, wherein the tap changer includes a motor with a driven shaft and a load changer with a drive shaft, and the drive mechanism includes a cam disk, a drive gear, and a roller coupled to the drive gear. Here, the cam disk is connected to the driven shaft without relative rotation, and the drive gear is connected to the drive shaft without relative rotation. The driven shaft is located on the rotational axis of the cam disk. The cam disk has an inner profile and an outer profile that can be driven out by the roller. The inner profile and the outer profile each have a first region and a second region, the first region having a constant radius of curvature relative to the rotational axis, and the second region having a varying distance between the corresponding profile and the rotational axis of the cam disk, for example, decreasing or increasing. Here, the roller drives out of the profile during the rotational movement of the cam disk such that the roller drives out a portion of the first region of the outer profile, then directly drives out a portion of the second region of the outer profile, and then directly drives out a portion of the first region of the inner profile regardless of possible directional changes in the rotational movement of the cam disk.

[0008] The design, particularly the contour of the cam disc, causes the following during the on-load tap changer switching process: the selector initially moves at a constant speed and then actuates the load changer relatively quickly, particularly in a hopping manner, without the need for idling for decoupling or the energy storage spring for actuating the load changer. This has the advantage that commutation is generally possible during the switching process. The interruption of commutation, or the switching process, accompanied by the return of the selector or load changer to its initial position, may be necessary, for example, when a fault is detected in the on-load tap changer by a monitoring device. This fault means: the on-load tap changer not functioning as intended, for example, increased torque on the drive shaft and / or driven shaft, or other faults detected in the on-load tap changer by a sensing mechanism. Depending on the corresponding fault condition, the switching process can then be reliably interrupted.

[0009] Furthermore, it is advantageous in the transmission device according to the improved design that the transmission device has fewer components and therefore can operate more simply and reliably.

[0010] According to at least one embodiment, the roller travels out of the contour as the cam disk rotates, such that the roller travels out of a portion of a first region of the inner contour, then directly out of a portion of a second region of the inner contour, and then directly out of a portion of a first region of the outer contour, regardless of any possible directional changes in the rotational motion of the cam disk.

[0011] According to at least one embodiment, a portion of the first region of the inner contour and / or a portion of the first region of the outer contour are disposed between the second region of the inner contour and the second region of the outer contour.

[0012] According to at least one embodiment, when the roller moves from the second region of the inner contour to the second region of the outer contour and vice versa, the roller must move through a portion of the first region of the inner contour or a portion of the first region of the outer contour.

[0013] According to at least one embodiment, the second region of the inner contour is opposite to the second region of the outer contour.

[0014] According to at least one embodiment, the transmission device is configured such that the drive gear is operated for the switching process of the load transfer switch.

[0015] In at least one embodiment, the drive gear does not move during the period when the roller exits the first region of one of the contours. In particular, the selector moves at a constant speed during the period when the roller exits the first region of one of the contours, and in particular, the load changeover switch does not move during the movement of the selector.

[0016] According to at least one embodiment, the drive gear moves during the period when the roller exits the second region of one of the contours. In particular, during the period when the roller exits the second region of one of the contours, the load changeover switch moves rapidly and erratically, and in particular, the selector does not move during the movement of the load changeover switch.

[0017] According to at least one embodiment, the roller is disposed on a toothed element, preferably a gear section, and the toothed element is in operative connection with the drive gear.

[0018] In at least one embodiment, the transmission device includes a locking mechanism configured such that after the drive gear is actuated, the locking mechanism prevents the drive gear from continuing to move.

[0019] According to at least one embodiment, the locking mechanism is configured such that, after the switching process of the on-load tap changer, the switching unit that prevents the load transfer switch from coupling to the drive gear continues to move.

[0020] The locking mechanism ensures that the on-load tap changer obtains a new position after the switching process and maintains a safe distance between contacts during continuous operation. This contributes to a longer lifespan for the switching unit and therefore the entire on-load tap changer in the long run.

[0021] According to at least one embodiment, the transmission device includes a release mechanism configured such that the release mechanism releases the locking mechanism before the drive gear is operated, thereby allowing the drive gear to move.

[0022] According to at least one embodiment, the release mechanism is configured such that the switching unit of the load transfer switch can be manipulated during the switching of the on-load tap changer.

[0023] In at least one embodiment, the cam disk has a third profile, within which at least one scanner operates. The third profile has a first region and a second region, the first region having a constant radius of curvature relative to a rotation axis, and the second region having a varying distance from the rotation axis of the cam disk, for example, increasing and / or decreasing. The at least one scanner can drive out of the first and second regions of the third profile.

[0024] According to at least one embodiment, the at least one scanner cooperates with the locking mechanism and / or the releasing mechanism such that the locking mechanism is released while the at least one scanner is traveling out of a portion of the first region of the third curve, and the locking mechanism is activated while the at least one scanner is traveling out of the second region of the third curve.

[0025] For example, the locking mechanism can be released at any time when the at least one scanner is in the first region.

[0026] For example, the locking mechanism can be activated at any time when the at least one scanner is in the second region.

[0027] For example, the locking mechanism can be released at any time when the at least one scanner is in the second region.

[0028] According to at least one embodiment, the locking mechanism and / or the releasing mechanism includes at least one claw and at least one protrusion, the at least one claw being connected to the at least one scanner, and the at least one protrusion being disposed on the drive gear.

[0029] According to at least one embodiment, the locking mechanism is activated in such a way that the at least one claw engages with the at least one protrusion.

[0030] According to at least one embodiment, the locking mechanism is released in such a way that the at least one claw is released from the at least one protrusion.

[0031] In at least one embodiment, the transmission device includes a monitoring device for determining the position, particularly the absolute position, of the driving shaft, driven shaft, or another shaft coupled thereto. The monitoring device may, for example, be a position encoder, particularly an absolute encoder.

[0032] The position of the shaft, determined by the monitoring device, can be used to determine, in the event of disturbance, especially during the operation of the load transfer switch, whether the switching process should be guided to the end, or whether the on-load tap changer should return to the stop position and / or return to its initial position.

[0033] According to the improved design, an on-load tap changer is also provided, which includes a motor with a driven shaft, a load transfer switch with a drive shaft, and a transmission device according to the improved design.

[0034] The explanation of the transmission device according to the improved design, especially the various features, is similarly applicable to the on-load tap changer according to the improved design, and vice versa. Attached Figure Description

[0035] The invention will now be explained in detail with reference to the accompanying drawings and exemplary embodiments. Components that are functionally identical or have the same effect may be provided with the same reference numerals. Identical components or components with the same function may be explained only with respect to the first drawing in which they appear. The explanation is not necessarily repeated in subsequent drawings.

[0036] In the attached image:

[0037] Figure 1 A schematic construction of an exemplary embodiment of an on-load tap changer having a transmission device according to the improved design described herein is shown;

[0038] Figure 2 An exemplary embodiment of the transmission device according to the improved design is shown;

[0039] Figure 3 Show Figure 2 Another view of the exemplary implementation in the example;

[0040] Figure 4 An exemplary embodiment of the cam disk of the transmission device according to the improved design is shown. Detailed Implementation

[0041] exist Figure 1An exemplary embodiment of an on-load tap changer S is schematically shown, which exemplarily includes a motor M having a driven shaft ABW, a load changer LU having a drive shaft ANW, a selector W, and a transmission G. The load changer LU and selector W are constructed in a known manner and are therefore not shown further. The selector W includes a plurality of fixed contacts (not shown) and two movable contacts (not shown) and is coupled to the driven shaft ABW for driving the movable contacts. The load changer LU includes movable contact units for load switching (not shown) and is coupled to the drive shaft ANW for driving the contact units. The drive shaft ANW is coupled to the driven shaft ABW via the transmission G, and the motor M drives the driven shaft, for example, at a constant speed, during the switching of the on-load tap changer S.

[0042] exist Figure 2 An exemplary embodiment of a transmission device G according to the improved design is shown. The transmission device G includes a cam disk KS, a drive gear ANZ, and a roller R coupled to the drive gear ANZ. The cam disk KS is connected to the driven shaft ABW without relative rotation and is driven by a motor M via the driven shaft ABW. Here, the cam disk KS rotates about a rotation axis RA1, on which the driven shaft ABW is located. The drive gear ANZ is connected to the drive shaft ANW without relative rotation and thus drives the contact unit (not shown) of the load changeover switch LU. The roller R is mounted on a gear section ZS, which is in operative connection with the drive gear ANZ, and the load changeover switch LU alternately moves about axis RA2 from one rotational direction to another during each switching process. The cam disk KS has an inner contour IK and an outer contour AK, which are respectively included in... Figure 4 Different regions are indicated by dashed lines. However, other definitions for these regions are also conceivable, provided they satisfy the functions of the regions explained below. Two contours, IK and AK, each have a first region IKB1 and AKB1 and a second region IKB2 and AKB2, respectively. In the first region, the radius of curvature of the contour is constant relative to the axis of rotation RA1. In the second region, the distance between contours IK and AK and the axis of rotation RA1 varies. For example, in the second region of the inner contour IKB2, the distance first becomes larger and then smaller, and in the second region of the outer contour AKB2, it first becomes smaller and then larger. Furthermore, the cam disk KS has a third contour KK, which also includes a first region KKB1 and a second region KKB2. The first region KKB1 has a constant radius of curvature relative to the axis of rotation RA1, and in the second region KKB2, the distance between the contour and the axis of rotation RA1 varies, for example, first becoming smaller, then larger, and then smaller again, as in… Figure 4 As shown in the diagram.

[0043] The operating principle of the transmission device G is as follows: During the switching of the tap changer S, the driven shaft ABW is operated by the motor M at a constant speed, for example, and the cam disk KS is rotated by the driven shaft. While the cam disk KS rotates about the rotation axis RA1, the roller R moves out of the contour. The roller R, for example, first moves out of a portion of the first region of the outer contour AKB1 when rotating in the direction R1, in such a way that the contour has a constant radius of curvature. Simultaneously, at least one movable contact of the selector W connects the new winding tap of the transformer to be wired without load. Then, the roller R reaches the second region of the outer contour AKB2, now ending the selector movement. In this region, the distance between the outer contour AK and the rotation axis RA1 first decreases, and thus the roller R similarly reduces the distance between the roller and the rotation axis RA1. As a result, the gear segment ZS rotates rapidly, particularly in a jumping motion, about the axis RA2 compared to the previous slow selector movement. This movement is transmitted directly to the driving gear ANZ via the teeth and thus to the driving shaft ANW. By manipulating the drive shaft ANW, the contact unit (not shown) of the load changeover switch LU is also actuated in a jump manner. Thus, independent operation of the selector W and then the load changeover switch LU is achieved first in each region of the profile traveled by the roller R.

[0044] If a new switching process is then started by manipulating the motor M, the roller R will first exit the inner contour IK before the roller reaches the second region of the inner contour IKB2, regardless of whether the cam disk KS moves along direction R1 or direction R2, and the load switching switch LU will be operated again in the second region.

[0045] During the switching process again, roller R then travels over the outer contour AK.

[0046] In addition, the transmission device has the ability to... Figure 2 and Figure 3 The locking or releasing mechanism is shown in the diagram. This locking or releasing mechanism includes two claws KL1 and KL2, each having a scanner A1 and A2, which extend from the third profile KK of the cam disk KS. Scanners A1 and A2 can be constructed, for example, in a rod-like configuration. The two claws KL1 and KL2 cooperate with two protrusions V1 and V2, which are disposed on the drive gear ANZ. If one of the claws KL1 or KL2 is, for example, on one of the protrusions V1 or V2, i.e., in a locked state, the drive gear ANZ cannot move and the locking mechanism is active.

[0047] The locking or releasing mechanism operates as follows: At the start of the switching process, the cam disk KS moves, for example, along the rotation direction R1, and the first scanner A1 first moves out of a portion of the second region of the third contour KK. In this region, the first claw KL1 is in a locked state on the first protrusion V1. In this state, the locking mechanism is active, so the drive gear ANZ cannot move. As the cam disk KS rotates further, the first scanner A1 reaches the first region of the third contour KKB1. Thus, the first claw KL1 releases from the first protrusion V1 and the drive gear ANZ can move. In the further progress of the rotational movement of the cam disk KS, the second scanner A2 reaches the second region of the third contour KKB2. Because the distance between the contour and the rotation axis RA1 changes here, especially becomes smaller, the scanner A2 is also positioned closer to the rotation axis RA1, and the claw KL2 follows the scanner, then locking in the second protrusion V2. Here, the claws KL1 and KL2, together with the two scanners A1 and A2, the protrusions V1 and V2, and the areas of the third contours KKB1 and KKB2, are arranged and designed in such a way that the two claws are disengaged or released before the load change, so that the drive gear ANZ can move, and directly after the load change, one of the two claws locks onto one of the two protrusions, thereby ensuring that the drive gear ANZ cannot continue to move after the operation.

[0048] The task is solved by the transmission mechanism according to the improved design, and particularly ensured by the design of the cam disc profile: the selector moves in the first region of the profile, and the switching unit of the load changeover switch is operated in the second region of the profile. This achieves the working principle of accumulators known in the prior art, whereby the operation of the load changeover switch is abruptly and decoupled from the selector movement, while simultaneously avoiding the drawbacks of known accumulators, namely, that in the event of a failure, reversal of the switching process is no longer possible due to idling and springs. Because, according to the transmission mechanism of the improved design, reversal or interruption of the switching process, accompanied by the return of the selector or load changeover switch to its initial position, is possible at virtually every moment of the switching process.

[0049] List of reference numerals

[0050] S tap changer

[0051] M motor

[0052] ABW driven shaft

[0053] ANW drive shaft

[0054] G transmission device

[0055] LU Load Transfer Switch

[0056] W Selector

[0057] KS Cam Disc

[0058] R roller

[0059] ANZ drive gear

[0060] AK outer contour

[0061] IK Inner Contour

[0062] KK Third Outline

[0063] RA1, RA2 rotation axes

[0064] ZS toothed element

[0065] A1 and A2 scanners

[0066] KU, KL2 claw

[0067] V1 and V2 protrusions

[0068] The first area of ​​AKB1's outer outline

[0069] The second area of ​​AKB2's outer outline

[0070] The first area of ​​the inner contour of IKB1

[0071] The second area of ​​the inner contour of IKB2

[0072] KKB1 Third Outline First Area

[0073] The second region of the third outline of KKB2.

Claims

1. A drive mechanism (G) for an on-load tap changer (S), said on-load tap changer comprising a motor (M) having a driven shaft (ABW) and a load transfer switch (LU) having a drive shaft (ANW), The transmission device (G) includes: - Cam disk (KS), drive gear (ANZ), and roller (R) coupled to said drive gear, in, - The cam disk (KS) is connected to the driven shaft (ABW) without relative rotation, and the driven shaft is located on the rotation axis (RA1) of the cam disk (KS). The drive gear (ANZ) is connected to the drive shaft (ANW) without relative rotation. - The cam disk (KS) has an inner contour (IK) and an outer contour (AK) that can be driven out by the roller (R). The inner contour (IK) and outer contour (AK) each have a first region (IKB1, AKB1) and a second region (IKB2, AKB2), respectively. The first region has a constant radius of curvature, and in the second region, the distance between the corresponding contour and the axis of rotation (RA) of the cam disk (KS) varies. - The roller (R) moves out of the contour (IK; AK) as the cam disk (KS) rotates, such that the roller moves out of a portion of the first region (AKB1) of the outer contour, then out of a portion of the second region (AKB2) of the outer contour, and then out of a portion of the first region (IKB1) of the inner contour.

2. The transmission device according to claim 1, wherein, - A portion of the first region (IKB1) of the inner contour and / or a portion of the first region (AKB1) of the outer contour are disposed between the second region (IKB2) of the inner contour and the second region (AKB2) of the outer contour.

3. The transmission device according to claim 1 or 2, wherein, - During the period when the roller (R) travels out of the first region (IKB1, AKB1) of one of the contours, the drive gear (ANZ) does not move.

4. The transmission device according to claim 1 or 2, wherein, - The drive gear (ANZ) moves during the period when the roller (R) travels out of the second region (IKB2, AKB2) of one of the contours.

5. The transmission device according to claim 1 or 2, wherein, - The roller (R) is mounted on the toothed element (ZS), which is in operative connection with the drive gear (ANZ).

6. The transmission device according to claim 1 or 2, wherein, - The transmission device (G) is configured such that the drive gear (ANZ) is operated for the switching process of the load changeover switch (LU).

7. The transmission device according to claim 6, wherein, - The transmission device (G) includes a locking mechanism configured such that after the drive gear (V) is actuated, the locking mechanism prevents the drive gear from continuing to move.

8. The transmission device according to claim 7, wherein, - The transmission device includes a release mechanism configured such that the release mechanism releases the locking mechanism before the drive gear (ANZ) is operated, thereby enabling the drive gear to move.

9. The transmission device according to claim 8, wherein, - The cam disk (KS) has a third profile (KK), and at least one scanner (A) operates within the third profile. - The third profile (KK) has a first region (KKB1) and a second region (KKB2), the first region having a constant radius of curvature, and the second region having a varying distance from the axis of rotation (RA) of the cam disk (KS).

10. The transmission device according to claim 9, wherein, - The at least one scanner (A) cooperates with the locking mechanism and / or the releasing mechanism such that the locking mechanism is released while the at least one scanner (A) is exiting a portion of the first region (KKB2) of the third curve, and - The locking mechanism is activated while at least one scanner (A) is exiting the second region (KKB1) of the third curve.

11. The transmission device according to claim 9 or 10, wherein, - The locking mechanism and / or the releasing mechanism includes at least one claw (KL) and at least one protrusion (V), the at least one claw being connected to the at least one scanner (A), and the at least one protrusion being disposed on the drive gear (ANZ).

12. An on-load tap changer, the on-load tap changer comprising: - A motor (M) having a driven shaft (ABW), a load changeover switch (LU) having a drive shaft (ANW), and a transmission device (G), said transmission device being configured as a transmission device according to any one of claims 1 to 11.

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