JP7489446B2 - Torque adjusting device and tap changer - Google Patents

Description

This technology relates to a torque adjustment device and a tap changer that adjust the magnitude of torque around a drive shaft.

Conventionally, tap changers have been proposed that switch the connection between the neutral point of a transformer and the odd or even taps. A switch is provided between the neutral point and the odd or even taps, and switching is performed by operating the switch. Vacuum valves are provided between the neutral point and the switch, and between the neutral point and the odd taps.

The tap changer includes a drive shaft, a drive cam fitted to the outside of the drive shaft, a cam follower in contact with the circumferential surface of the drive cam, a spring, and a charging mechanism for charging the spring. After the spring is fully charged, a torque due to the force of the spring (hereinafter referred to as the first torque) acts on the drive shaft, causing the drive shaft to rotate and the cam follower to move. The displacement of the cam follower is transmitted to the vacuum valve and the switch, and the opening and closing of the vacuum valve and the switching of the switch are performed at a predetermined timing (see, for example, Patent Document 1).

JP 2004-319975 A

The first torque changes over time. A torque (hereinafter referred to as the second torque) is also generated from the cam follower to the drive cam. If the first torque is too large, or if the first torque and the second torque are torques in the same direction, the switching speed becomes too fast, and the timing of opening and closing the vacuum valve and switching the switch may deviate significantly from the specified timing. If the first torque and the second torque are torques in opposite directions, the torque that rotates the drive shaft becomes too small, and the opening and closing of the vacuum valve and switching of the switch may not be executed.

This disclosure has been made in light of these circumstances, and aims to provide a torque adjustment device and tap changer that can adjust the torque around the drive shaft.

The torque adjustment device according to the present disclosure includes a drive shaft that rotates around an axis, an adjustment cam that fits around the outside of the drive shaft and adjusts torque, a plurality of cam followers that contact the peripheral surface of the adjustment cam, a biasing member that biases the cam followers toward the adjustment cam, a connecting member that connects the biasing member and the cam followers and is rotatable around an axis that intersects the drive shaft, a first lever that extends radially of the drive shaft and has one end fixed to an end of the drive shaft, a biasing spring for accumulating force acting on the other end of the first lever, a biasing mechanism that biases the biasing spring, and a stopper mechanism that restrains the drive shaft and releases the restraint of the drive shaft.
The energy storage mechanism of the torque adjustment device disclosed herein includes a first spring receiving member attached to the other end of the first lever, a support portion extending along the drive shaft, a second lever having one end rotatably connected to the support portion and extending radially of the drive shaft, a second spring receiving member attached to the other end of the second lever, and a rotation mechanism that rotates the second lever, and the energy storage spring is connected to the first spring receiving member and the second spring receiving member.
The rotation mechanism of the torque adjustment device disclosed herein has a rotating member that rotates around an axis parallel to the drive shaft, a third lever extending from the rotating member in the radial direction of the drive shaft, and a fourth lever extending in the radial direction of the drive shaft and connected to the third lever and the second lever.

In this disclosure, the cam follower contacts the adjustment cam due to the biasing force of the biasing member. The cam follower moves along the cam surface formed on the circumferential surface of the adjustment cam, and the biasing member absorbs or releases energy to adjust the torque around the drive shaft.

The tap changing device of the present disclosure comprises a drive shaft that rotates around an axis, a drive cam that fits around the outside of the drive shaft and switches taps, an adjustment cam that fits around the outside of the drive shaft and adjusts torque, a plurality of cam followers that contact the peripheral surface of the adjustment cam, a biasing member that biases the cam followers toward the adjustment cam, a connecting member that connects the biasing member and the cam followers and is rotatable around an axis that intersects the drive shaft, a first lever that extends radially of the drive shaft and has one end fixed to an end of the drive shaft, a biasing spring that accumulates force acting on the other end of the first lever, a biasing mechanism that accumulates force in the biasing spring, and a stopper mechanism that restrains the drive shaft and releases the restraint of the drive shaft.
The energy storage mechanism of the tap changing device disclosed herein includes a first spring receiving member attached to the other end of the first lever, a support portion extending along the drive shaft, a second lever having one end rotatably connected to the support portion and extending radially of the drive shaft, a second spring receiving member attached to the other end of the second lever, and a rotation mechanism for rotating the second lever, and the energy storage spring is connected to the first spring receiving member and the second spring receiving member.
The rotation mechanism of the tap changing device of the present disclosure has a rotating member that rotates around an axis parallel to the drive shaft, a third lever extending from the rotating member in the radial direction of the drive shaft, and a fourth lever extending in the radial direction of the drive shaft and connected to the third lever and the second lever.

In this disclosure, the cam follower is in contact with the adjustment cam by the biasing force of the biasing member. The cam follower moves along the cam surface formed on the circumferential surface of the adjustment cam, and the biasing member absorbs or releases energy, adjusting the torque around the drive shaft and adjusting the torque generated by the drive cam.

In the tap changing device of the present disclosure, a first recess is formed on the circumferential surface of the drive cam and a second recess is formed on the circumferential surface of the adjustment cam, and the position of the first recess is different from the position of the second recess around the drive shaft.

In the present disclosure, the first recess of the drive cam and the second recess of the adjustment cam are positioned differently around the drive shaft. This prevents the cam follower from moving through the first recess and the second recess simultaneously, preventing an extreme increase or decrease in torque.

The tap changer according to the present disclosure has a first convex portion formed on the circumferential surface of the drive cam, a second convex portion formed on the circumferential surface of the adjustment cam, and the position of at least a portion of the first convex portion is the same as the position of the second concave portion around the drive shaft, and the position of at least a portion of the second convex portion is the same as the position of the first concave portion around the drive shaft.

In the present disclosure, in the circumferential direction of the drive shaft, at least a portion of the first convex portion overlaps with the second concave portion, and at least a portion of the second convex portion overlaps with the first concave portion. Therefore, the torque from the drive cam is easily offset by the adjustment cam, and the power supplied to the drive shaft can be reduced. As a result, the power supply configuration can be made more compact, the tap changer can be made more compact, and the manufacturing costs of the tap changer can be reduced.

In the torque adjustment device and tap changer disclosed herein, the cam follower is in contact with the adjustment cam by the biasing force of the biasing member. The cam follower moves along the cam surface formed on the circumferential surface of the adjustment cam, and the biasing member absorbs or releases energy to adjust the torque around the drive shaft.

FIG. 2 is a diagram showing the electrical configuration of a tap selector and a tap changing device. FIG. 2 is a schematic longitudinal sectional view of a tap changer. FIG. FIG. FIG. 4 is a schematic plan view of an adjustment cam and a drive cam. FIG. 4 is a schematic plan view of an adjustment cam and a drive cam. FIG. 7 is a partially enlarged view showing a portion surrounded by line VII shown in FIG. 6 . FIG. 7 is a partially enlarged view showing a portion surrounded by line VIII shown in FIG. 6 . 4 is a graph showing an example of torque acting on a drive shaft.

The present invention will be described below with reference to the drawings showing a tap changer 100 according to an embodiment. FIG. 1 is a diagram showing the electrical configuration of the tap selector and the tap changer 100. The tap selector includes a tap winding Wt connected in series with the main winding Wm of the transformer, odd taps t1, t3, t5, ... provided on the tap winding Wt, an odd tap selector T1 that selects the odd tap, even taps t2, t4, t6, ... provided on the tap winding Wt, and an even tap selector T2 that selects the even tap. The odd tap selector T1 is electrically connected to the selected odd tap, and the even tap selector T2 is electrically connected to the selected even tap.

The tap changer 100 is equipped with a first vacuum valve Ma that opens and closes the load current that flows through the odd tap selector T1 and the even tap selector T2 during tap changing. One end of the first vacuum valve Ma is connected to the neutral point N of the transformer, and the other end is selectively connected to the odd tap selector T1 and the even tap selector T2 via a changeover switch SW.

The tap changer 100 further includes a current limiting resistor r that limits the short-circuit current between the taps when the taps are changed, and a second vacuum valve Mb that turns on and off the current limiting resistor r. One end of the second vacuum valve Mb is connected to the neutral point N, and the other end is connected to the odd tap selector T1 through the current limiting resistor r.

The load current is switched from one of the two taps selected by the tap selectors T1 and T2 to the other by the first vacuum valve Ma and the second vacuum valve Mb and the change-over switch SW.

When an odd tap is selected, the changeover switch SW is switched to the odd tap selector T1 side, and the first vacuum valve Ma and the second vacuum valve Mb are closed as shown. When an even tap is selected, the changeover switch SW is switched to the even tap selector T2 side, and the first vacuum valve Ma is closed and the second vacuum valve Mb is open.

For example, as shown in the figure, the changeover switch SW is connected to the tap selector T1 side, the first vacuum valve Ma and the second vacuum valve Mb are closed, and tap t1 is selected. When switching the tap from an odd tap to an even tap, for example from t1 to t2, the first vacuum valve Ma is first opened to allow the load current to flow through the current-limiting resistor r. Then, after switching the changeover switch SW to the tap selector T2 side without an arc, the first vacuum valve Ma is closed, and the vacuum valve Mb is opened to complete the tap switching. When the changeover switch SW is switched to the tap selector T2 side and the first vacuum valve Ma is closed, a short-circuit current flows between the taps through taps t1 and t2. This short-circuit current is limited by the current-limiting resistor r.

With the changeover switch SW switched to the tap selector T2 side, the first vacuum valve Ma and the second vacuum valve Mb are respectively closed and open to select tap t2. When switching from an even tap to an odd tap, for example when switching from t2 to t3, tap t3 is first selected by the tap selector T1. Then, the vacuum valve Mb is closed to pass the current limiting resistor r through the tap selector T1 and connect it to tap t3, and the first vacuum valve Ma is opened to pass the load current through the current limiting resistor r. Then, the changeover switch SW is switched to the tap selector T1 side without arcing, the first vacuum valve Ma is closed, and the tap switching is completed.

The tap changer 100 is provided with a drive mechanism that operates the switches constituting the changeover switch (in the above example, the first vacuum valve Ma, the second vacuum valve Mb, and the changeover switch SW) in a predetermined sequence in conjunction with the operation of the tap selector when changing the tap.

Figure 2 is a schematic longitudinal sectional view of the tap changer 100. The tap changer 100 includes an insulating tube 1. The insulating tube 1 extends in the vertical direction. A plate-shaped lower fixed frame 2 is provided inside the lower part of the insulating tube 1. A plate-shaped upper fixed frame 3 is provided above the lower fixed frame 2. A plate-shaped intermediate frame 50 is provided between the lower fixed frame 2 and the upper fixed frame 3. The lower fixed frame 2, the upper fixed frame 3, and the intermediate frame 50 are approximately parallel to each other and extend in a direction perpendicular to the axial direction of the insulating tube 1.

The intermediate frame 50 has a through hole (not shown) that penetrates in the vertical direction. The drive shaft 4, which has an axial direction in the vertical direction and can rotate around its axis, is inserted into the through hole. The drive shaft 4 is rotatably supported by the lower fixed frame 2 and the upper fixed frame 3 via bearings (not shown). The lower end of the drive shaft 4 penetrates the lower fixed frame 2 and protrudes downward beyond the lower fixed frame 2.

The drive unit 5 is disposed below the lower fixed frame 2. The drive unit 5 is connected to the lower end of the drive shaft 4. The drive force of the drive unit 5 causes the drive shaft 4 to rotate back and forth within a certain angular range between a first position and a second position. The first position is the rotation start position of the drive shaft 4 when the tap is switched from an odd tap to an even tap, and the second position is the rotation start position of the drive shaft 4 when the tap is switched from an even tap to an odd tap.

The drive unit 5 includes a spring 6, a storage mechanism 7 that stores energy in the spring 6, and a lever 8. The lever 8 extends in a direction substantially parallel to the lower fixed frame 2. One end of the lever 8 is fixed to the lower end of the drive shaft 4. A spring receiving member 9A is attached to the underside of the other end of the lever 8. A support post 10 is fixed to the underside of the lower fixed frame 2. The support post 10 protrudes downward from the lower fixed frame 2. The lower end of the support post 10 is located lower than the lever 8. One end of a lever 11 is rotatably connected to the lower end of the support post 10. The lever 11 rotates with the vertical direction as the rotation axis.

The lever 11 extends in a direction approximately parallel to the lower fixed frame 2. A spring receiving member 9B is provided at the other end of the lever 11. The spring receiving member 9B protrudes upward from the lever 11 and faces the spring receiving member 9A of the lever 8. The energy storage spring 6 has a tension spring, one end of which is connected to the spring receiving member 9A and the other end of which is connected to the spring receiving member 9B.

The support bracket 12 protrudes from the inner peripheral surface of the insulating tube 1 toward the radial center of the insulating tube 1. The support bracket 12 is disposed below the lever 11. A rotating member 13 is rotatably attached to the support bracket 12. The rotating member 13 receives power from a motor (not shown) and rotates with the vertical direction as the rotation axis.

A first lever 14 is connected to the rotating member 13. The first lever 14 extends from the rotating member 13 in a direction generally parallel to the lever 11. A pivot 14a with its axial direction extending vertically is provided at the tip of the first lever 14. A second lever 15 is attached to the pivot 14a. The second lever 15 extends in a direction generally parallel to the lever 11 and is disposed between the first lever 14 and the lever 11. The tip of the second lever 15 is connected to the underside of the lever 11 via the pivot 15a with its axial direction extending vertically.

When the drive shaft 4 is restrained in the first position or the second position (rotation start position) by the stopper mechanism described below and the rotating member 13 is rotated, the lever 11 rotates and the energy storage spring 6 is pulled and stored. When the stopper mechanism releases the drive shaft 4, the energy stored in the energy storage spring 6 is released in one go, and the drive shaft 4 rotates in one go from the first position to the second position, or from the second position to the first position.

Figures 3 and 4 are schematic plan views of the drive cam 16. Figure 4 shows the state in which the drive shaft 4 and the drive cam 16 have rotated counterclockwise in a plan view from the position shown in Figure 3. Between the intermediate frame 50 and the lower fixed frame 2, the plate-shaped drive cam 16 is fitted to the outside of the drive shaft 4. The drive cam 16 is approximately perpendicular to the drive shaft 4. The drive cam 16 is formed with a hole that penetrates vertically, and the drive shaft 4 is inserted into the hole. A cam surface 16a is formed on the peripheral surface of the drive cam 16. The cam surface 16a has three first convex portions 16u, 16v, and 16w arranged at 120° intervals, and a first concave portion 16c that connects these first convex portions 16u, 16v, and 16w.

Three first vacuum valves Ma for U-phase, V-phase, and W-phase are arranged around the drive shaft 4 at 120° intervals, and three second vacuum valves Mb for U-phase, V-phase, and W-phase are arranged at 120° intervals. The three second vacuum valves Mb are each arranged between the three first vacuum valves Ma.

Between the intermediate frame 50 and the lower fixed frame 2, three terminal fittings 17a corresponding to the three first vacuum valves Ma and three terminal fittings 17b corresponding to the three second vacuum valves Mb are provided on the inner surface of the insulating cylinder 1. The terminal fittings 17a and 17b are arranged below the drive cam 16. The vacuum valves Ma and Mb are arranged with their respective central axes facing in the vertical direction. Terminals are led out from the lower ends of the vacuum valves Ma and Mb, and these terminals are fixed to the terminal fittings 17a and 17b.

A support member 22 protrudes downward from the intermediate frame 50. L-shaped levers 20a and 20b for driving the vacuum valves corresponding to the first vacuum valve Ma and the second vacuum valve Mb, respectively, are provided between the intermediate frame 50 and the lower fixed frame 2. The middle corners of the L-shaped levers 20a and 20b are rotatably supported by the support member 22 via a rotating shaft 21 that extends in a direction perpendicular to the axis of the drive shaft 4.

A cam follower 23 made of a roller for driving the vacuum valve is attached to one end of the L-shaped levers 20a and 20b. The cam follower 23 rolls on the cam surface 16a. A movable shaft 24 protrudes upward from the upper end of the first vacuum valve Ma and the second vacuum valve Mb. The other end of the L-shaped levers 20a and 20b is connected to the movable shaft 24 of the corresponding first vacuum valve Ma and second vacuum valve Mb via a pin 25.

A spring 26 is disposed between the upper end of the movable shaft 24 and the intermediate frame 50, and the urging force of the spring 26 presses the cam follower 23 toward the cam surface 16a of the drive cam 16, causing it to come into contact with the cam surface 16a.

When the first convex portions 16u, 16v, 16w of the cam surface 16a of the drive cam 16 are separated from the cam followers 23 corresponding to the first vacuum valve Ma or the second vacuum valve Mb of the U-phase, V-phase, or W-phase, the first vacuum valve Ma or the second vacuum valve Mb is in a closed state.

When the first convex portions 16u, 16v, 16w of the cam surface 16a of the drive cam 16 come into contact with the cam follower 23 corresponding to the first vacuum valve Ma or the second vacuum valve Mb of the U-phase, V-phase, or W-phase, and the cam follower 23 is moved, the movable shaft 24 moves upward against the biasing force of the spring 26, and the first vacuum valve Ma or the second vacuum valve Mb becomes open.

A stopper mechanism 30 is provided to restrain the drive shaft 4 in the rotation start position (first position or second position) and prevent the drive shaft 4 from rotating until the energy storage spring 6 is fully charged.

The stopper mechanism 30 includes an auxiliary cam 31 fixed to the intermediate frame 50 side of the drive cam 16. The auxiliary cam 31 is arc-shaped and extends in the circumferential direction of the drive shaft 4, and a cam surface 31a is formed on its outer circumferential surface. The stopper mechanism 30 further includes an auxiliary cam follower 32 provided on the intermediate frame 50 side and abutting against the cam surface 31a of the auxiliary cam 31, and a spring 33 that biases the auxiliary cam follower 32 so as to press the auxiliary cam follower 32 toward the cam surface 31a.

An L-shaped lever 34 for a stopper mechanism having the same shape and dimensions as the L-shaped levers 20a and 20b is arranged above the auxiliary cam 31. Above the L-shaped lever 34, a support member 36 is fixed to the intermediate frame 50. The middle corner of the L-shaped lever 34 is supported by the support member 36 via a rotating shaft 35 extending in a direction perpendicular to the axis of the drive shaft 4. An auxiliary cam follower 32 is attached to one end of the L-shaped lever 34. The auxiliary cam follower 32 has a roller that rolls on the cam surface 31a. A spring support member 38 is attached to the other end of the L-shaped lever 34 via a pin 37. A spring 33 is provided between the spring support member 38 and the intermediate frame 50. The auxiliary cam follower 32 abuts against the cam surface 31a due to the biasing force of the spring 33.

As shown in Figures 3 and 4, the cam surface 31a has a first stopper portion 31a1 and a second stopper portion 31a2. The first stopper portion 31a1 and the second stopper portion 31a2 are spaced apart in the circumferential direction of the arc-shaped cam surface 31a. The first stopper portion 31a1 and the second stopper portion 31a2 protrude radially outward from the cam surface 31a. When the drive shaft 4 is in the first position, the auxiliary cam follower 32 engages with the opposite side of the second stopper portion 31a2 in the first stopper portion 31a1, preventing the drive shaft 4 from rotating to the second position. When the drive shaft 4 is in the second position, the auxiliary cam follower 32 engages with the opposite side of the second stopper portion 31a2 in the first stopper portion 31a1, preventing the drive shaft 4 from rotating to the first position. The force applied from the energy storage spring 6 through the drive shaft 4 and drive cam 16 prevents the drive shaft 4 from rotating until the auxiliary cam follower 32 overcomes the stopper portions 31a1 and 31a2.

When the first stopper portion 31a1 contacts the auxiliary cam follower 32 and prevents the auxiliary cam 31 from rotating in the clockwise direction, the drive shaft 4 is located in the first position. When the second stopper portion 31a2 contacts the auxiliary cam follower 32 and prevents the auxiliary cam 31 from rotating in the counterclockwise direction, the drive shaft 4 is located in the second position.

Below the drive cam 16, a movable contact 41 is attached to the peripheral surface of the middle part of the drive shaft 4 via an insulating member 40. A pair of fixed contacts 42, 42 (only one of the fixed contacts 42 is shown in FIG. 2) are fixed to the inner peripheral surface of the insulating tube 1 with a gap in the rotation direction of the drive shaft 4 so as to face the insulating member 40 and the movable contact 41. The movable contact 41 selectively contacts one of the two fixed contacts 42, 42 as the drive shaft 4 rotates. The movable contact 41 and the fixed contacts 42, 42 form a change-over switch SW. One of the pair of fixed contacts 42, 42 is connected to the odd tap selector, and the other is connected to the even tap selector. The movable contact 41 is also connected to the movable contact side terminal (movable shaft 24) of the first vacuum valve Ma of the corresponding phase via a wire (not shown).

A three-phase current limiting resistor r is placed in the space above the upper fixed frame 3, and the current limiting resistor r is connected between the second vacuum valve Mb of each phase and the odd tap selector. In FIG. 2, the three-phase current limiting resistor r, the odd tap selector, and the even tap selector are omitted.

When the three-phase changeover switch SW is switched to the odd tap selector T1 side, the vacuum valves Ma and Mb are closed, and an odd tap is selected, the drive shaft 4 is in a position slightly past the first position. At this time, the first stopper portion 31a1 is in a position slightly past the position where it contacts the auxiliary cam follower 32 (the position shown in Figure 3) in the counterclockwise direction.

When the tap is switched to an even tap from this state, the energy storage mechanism 7 stores the energy storage spring 6. At this time, as shown in FIG. 3, the first stopper portion 31a1 abuts against the auxiliary cam follower 32, restraining the drive shaft 4 in the first position and preventing its rotation, and the energy storage spring 6 is allowed to proceed with the energy storage. When the energy storage spring 6 is fully charged, the force transmitted from the energy storage spring 6 to the auxiliary cam 31 through the drive shaft 4 exceeds the pressing force applied from the spring 33 to the auxiliary cam follower 32, and the engagement between the stopper portion 31a1 and the auxiliary cam follower 32 is released, so that the auxiliary cam 31 starts to rotate together with the drive cam 16 and the drive shaft 4, and the energy stored in the energy storage spring 6 is released all at once, and the drive shaft 4 rotates all at once in the clockwise direction as shown by the arrow in FIG. 4. During this rotation of the drive shaft 4, the drive cam 16 opens the first vacuum valve Ma and passes the load current through the current-limiting resistor r. Next, the three-phase changeover switch SW is switched to the tap selector T2 side without arcing, the first vacuum valve Ma is closed, and the vacuum valve Mb is opened to complete the tap switching. After the tap switching is completed and the auxiliary cam follower 32 has exceeded the second stopper portion 31a2 of the auxiliary cam 31 (the stopper portion 31a2 has slightly passed the position where it contacts the auxiliary cam follower 32 in the clockwise direction), the drive shaft 4 stops.

When switching the tap from this state to an odd tap, the energy storage spring 6 is charged again by the energy storage mechanism 7. At this time, the second stopper portion 31a2 abuts against the auxiliary cam follower 32, restraining the drive shaft 4 in the second position to prevent its rotation, and the energy storage spring 6 is charged. When the energy storage spring 6 is fully charged, the force transmitted from the energy storage spring 6 to the auxiliary cam 31 through the drive shaft 4 exceeds the pressing force applied to the auxiliary cam follower 32 by the spring 33, disengaging the stopper portion 31a2 of the auxiliary cam 31 from the auxiliary cam follower 32, and the auxiliary cam 31 starts to rotate together with the drive cam 16. During the rotation of the drive shaft 4, the drive cam 16 first closes the vacuum valve Mb, then opens the vacuum valve Ma to allow the load current to flow through the current limiting resistor r. Next, the three-phase changeover switch SW is switched to the tap selector T1 side without arcing, and the first vacuum valve Ma is closed to complete the tap switching. When tap switching is completed and the auxiliary cam follower 32 has exceeded the first stopper portion 31a1 of the auxiliary cam 31 (slightly going counterclockwise past the position in FIG. 3 where the stopper portion 31a1 contacts the auxiliary cam follower 32), the drive shaft 4 stops.

5 and 6 are schematic plan views of the adjustment cam 51 and the drive cam 16. FIG. 6 shows the state in which the drive shaft 4, the adjustment cam 51, and the drive cam 16 have rotated counterclockwise in a plan view from the position shown in FIG. 5. FIG. 5 corresponds to FIG. 3, and FIG. 6 corresponds to FIG. 4. Between the intermediate frame 50 and the upper fixed frame 3, the plate-shaped adjustment cam 51 is fitted to the outside of the drive shaft 4. The adjustment cam 51 is approximately perpendicular to the drive shaft 4. The adjustment cam 51 has a hole that penetrates vertically, and the drive shaft 4 is inserted into the hole. A cam surface 51a is formed on the peripheral surface of the adjustment cam 51. The cam surface 51a has three second convex portions 51u, 51v, and 51w arranged at intervals of 120°, and a second concave portion 51c that connects these second convex portions 51u, 51v, and 51w.

The adjustment cam 51 has a shape similar to that of the drive cam 16. As shown in FIG. 5, the positions of the tops of the second convex portions 51u, 51v, and 51w are offset by approximately 60° from the tops of the first convex portions 16u, 16v, and 16w around the axis of the drive shaft 4. When viewed from the axial direction of the drive shaft 4, the second convex portions 51u, 51v, and 51w are arranged so as to overlap the first recess 16c, and the tops of the first convex portions 16u, 16v, and 16w are arranged so as to overlap the second recess 51c. In other words, the positions of the first recess 16c and the second recess 51c are different around the drive shaft 4.

Three L-shaped levers 52 are arranged around the adjustment cam 51. Three support members 54 protrude downward from the upper fixed frame 3. The three support members 54 correspond to the three L-shaped levers 52, respectively. The corners of the L-shaped levers 52 are rotatably supported by the support members 54 via a rotating shaft 53 that extends perpendicular to the axis of the drive shaft 4.

A cam follower, for example a roller follower 55 having a roller, is attached to one end of the L-shaped lever 52. A spring 56 is provided between the other end of the L-shaped lever 52 and the upper fixed frame 3. The roller follower 55 is urged toward the cam surface 51a of the adjustment cam 51 by the urging force of the spring 56. The roller follower 55 abuts against the cam surface 51a and rolls on the cam surface 51a. The torque adjustment device includes the adjustment cam 51, the L-shaped lever 52, the pivot shaft 53, the support member 54, the roller follower 55, and the spring 56.

Figure 7 is a partial enlarged view showing the part surrounded by line VII in Figure 6, and Figure 8 is a partial enlarged view showing the part surrounded by line VIII in Figure 6. When the drive shaft 4 rotates clockwise, as shown in Figure 7, one cam follower 23 is pushed outward in the radial direction by the first convex portion 16u. On the other hand, as shown in Figure 8, one roller follower 55 corresponding to the one cam follower 23 moves inward in the radial direction by moving through the second concave portion 51c.

In other words, the force caused by the movement of one cam follower 23 acts on the drive shaft 4 as a torque (load torque) in the opposite direction to the torque acting on the drive shaft 4 by the biasing force of the energy storage spring 6, and the force caused by the movement of one roller follower 55 acts on the drive shaft 4 as a torque (driving torque) in the same direction as the torque acting on the drive shaft 4 by the biasing force of the energy storage spring 6, and the two are attenuated or offset by each other. In other words, the spring 56 of the adjustment cam 51 absorbs energy from the driving torque caused by the movement of the cam follower 23, and releases the absorbed energy from the load torque caused by the movement of the cam follower 23.

When the first roller follower 55 is pushed outward in the radial direction by the second convex portions 51u-w, the first cam follower 23 moves through the first concave portion 16c and moves inward in the radial direction. That is, the force caused by the movement of the first roller follower 55 acts on the drive shaft 4 as a load torque, and the force caused by the movement of the first cam follower 23 acts on the drive shaft 4 as a drive torque, and the two are attenuated or offset.

Figure 9 is a graph showing an example of torque acting on the drive shaft 4. In Figure 9, T1 indicates the torque acting on the drive shaft 4 due to the movement of the cam follower 23, T2 indicates the torque acting on the drive shaft 4 due to the movement of the roller follower 55, and T3 and T4 indicate the torque acting on the drive shaft 4 by the energy storage spring 6. The vertical axis indicates each torque. The horizontal axis indicates the rotation angle of the drive shaft 4. In the torques T1 and T2, positive torque indicates the load torque acting on the drive shaft 4, and negative torque indicates the drive torque acting on the drive shaft 4. In the torques T3 and T4, positive torque indicates the drive torque acting on the drive shaft 4, and negative torque indicates the load torque acting on the drive shaft 4.

As shown in FIG. 9, for example, at an angle of approximately 15 degrees to 25 degrees or approximately 55 degrees to 65 degrees, when the roller follower 55 is pushed radially outward by the second convex portions 51u to w and the cam follower 23 moves through the first concave portion 16c and moves radially inward, a load torque acts on the drive shaft 4 due to the movement of the roller follower 55, and a drive torque acts on the drive shaft 4 due to the movement of the cam follower 23, and both are attenuated or offset. In other words, an extreme increase in the resultant torque acting on the drive shaft 4 can be prevented.

For example, when the cam follower 23 is pushed radially outward by the first convex portion 16u at an angle of approximately 27 degrees to 37 degrees or approximately 67 degrees to 77 degrees, and the roller follower 55 moves through the second concave portion 51c and moves radially inward, a load torque acts on the drive shaft 4 due to the movement of the cam follower 23, and a drive torque acts on the drive shaft 4 due to the movement of the roller follower 55, and the two are attenuated or offset.

As the drive shaft 4 rotates, the energy stored in the energy storage spring 6 decreases. That is, as shown in FIG. 9, the torque T3 from the energy storage spring 6 decreases as the drive shaft 4 rotates. Therefore, for example, at an angle of approximately 27 degrees to 37 degrees or approximately 67 degrees to 77 degrees, if the torque T3 decreases and a load torque acts on the drive shaft 4 due to the movement of the cam follower 23, the resultant torque decreases extremely and becomes zero or a negative value, and there is a risk that the drive shaft 4 will stop.

However, the movement of the roller follower 55 causes a driving torque to act on the drive shaft 4. That is, even if the force caused by the movement of the cam follower 23 acts as a load torque, the force caused by the movement of the roller follower 55 acts as a driving torque, and the load torque is attenuated, so the resultant torque acting on the drive shaft 4 tends to maintain a positive value. Therefore, the drive shaft 4 can continue to rotate without stopping until it is stopped by the stopper portion 31a1 or 31a2. That is, the tap changer 100 prevents an extreme decrease in the resultant torque and allows the drive shaft 4 to continue rotating.

Conventionally, the torque due to the biasing force of the energy storage spring 6 was set to a magnitude that would not stop the drive shaft 4 even if a load torque acting due to the movement of the cam follower 23 was applied, for example, to torque T3. In this embodiment, as described above, the torque T1 generated by the movement of the cam follower 23 is attenuated or offset by the torque T2 generated by the movement of the roller follower 55. Therefore, for example, the torque due to the biasing force of the energy storage spring 6 can be set to torque T4, which is smaller than torque T3. Since the torque due to the biasing force of the energy storage spring 6 can be reduced, the strength required for the drive unit 5 is reduced, and the drive unit 5 can be made smaller. In addition, the configuration of the components that make up the drive unit 5, for example, the configuration of the energy storage spring 6, can be simplified, and the manufacturing costs of the tap changer 100 can be reduced.

The torque adjustment device and tap changer 100 according to the embodiment can adjust the torque caused by the rotation of the drive shaft 4. In addition, the rotation speed of the drive cam 16 can be adjusted to open and close the vacuum valves Ma and Mb and to switch the changeover switch SW at a predetermined timing.

The roller follower 55 is in contact with the adjustment cam 51 by the biasing force of the spring 56. The roller follower 55 moves along the cam surface 51a formed on the circumferential surface of the adjustment cam 51, and the spring 56 absorbs or releases energy in response to the torque generated by the movement of the cam follower 23, thereby adjusting the torque around the drive shaft 4.

In addition, the first recess 16c of the drive cam 16 and the second recess 51c of the adjustment cam 51 are positioned differently around the drive shaft 4. This prevents the cam followers 23 and 55 from moving simultaneously through the first recess 16c and the second recess 51c, respectively, and prevents an extreme increase or decrease in torque.

In addition, in the circumferential direction of the drive shaft 4, at least a portion of the first convex portions 16u, 16v, and 16w overlaps with the second concave portion 51c, and at least a portion of the second convex portions 51u, 51v, and 51w overlaps with the first concave portion 16c. Therefore, the torque from the drive cam 16 is easily offset by the adjustment cam 51, and the power supplied to the drive shaft 4 can be reduced. As a result, the power supply configuration can be made more compact, the tap changer 100 can be made more compact, and the manufacturing costs of the tap changer 100 can be reduced.

The positions of the first convex portions 16u, 16v, 16w, the first recess 16c, the second convex portions 51u, 51v, 51w, and the second recess 51c shown in the above embodiment are merely examples, and the first convex portions 16u, 16v, 16w, the first recess 16c, the second convex portions 51u, 51v, 51w, and the second recess 51c can be set at any positions. The above-mentioned torque adjustment device can also be applied to devices other than the tap changer 100, and can adjust the torque in the device. The torque adjustment device can also be used not only to reduce or cancel torque, but also to increase torque.

The embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is intended to include all modifications within the scope of the claims and equivalents to the scope of the claims. The matters described in each embodiment can be combined with each other. In addition, the independent claims and dependent claims described in the claims can be combined with each other in all combinations regardless of the citation format. Furthermore, the claims use a format in which a claim cites two or more other claims (multi-claim format), but this is not limited to this. They may also be written in a format in which a multiple claim cites at least one other claim (multi-multi-claim).

4 Drive shaft 16 Drive cam 16c First recess 16u, 16v, 16w First protrusion 51 Adjustment cam 51a Cam surface 51c Second recess 51u, 51v, 51w Second protrusion 52 L-shaped lever (connecting member)
55 Roller follower (cam follower)
56 Spring (biasing member)

Claims (5)

A drive shaft that rotates around an axis;
A drive cam that is fitted onto the outside of the drive shaft and is used for switching taps;
a plurality of first cam followers in contact with a peripheral surface of the drive cam;
a first biasing member that biases the first cam follower toward the drive cam;
an adjustment cam that is fitted onto the outside of the drive shaft and that adjusts torque;
A plurality of second cam followers contacting a peripheral surface of the adjustment cam;
A second biasing member that biases the second cam follower toward the adjustment cam;
a connecting member that connects the second biasing member and the second cam follower and is rotatable about an axis that intersects with the drive shaft;
a first lever extending in a radial direction of the drive shaft and having one end fixed to an end of the drive shaft;
a spring for storing a force acting on the other end of the first lever;
a storage mechanism for storing energy in the storage spring;
a stopper mechanism that restrains the drive shaft and releases the restraint of the drive shaft ;
Equipped with
The stopper mechanism includes:
an auxiliary cam fixed to the drive cam;
an L-shaped lever that is rotatable about a rotation axis extending in a direction perpendicular to the axis of the drive shaft;
an auxiliary cam follower attached to one end of the L-shaped lever and in contact with a cam surface of the auxiliary cam;
a third biasing member disposed at the other end of the L-shaped lever for pressing the auxiliary cam follower toward the cam surface;
Equipped with
The cam surface has a first stopper portion and a second stopper portion that are spaced apart from each other,
the first stopper portion and the second stopper portion are arranged such that, when the drive shaft is in a first position, the auxiliary cam follower engages with the first stopper portion, and, when the drive shaft is in a second position, the auxiliary cam follower engages with the second stopper portion;
a first recess and a first protrusion are formed on a peripheral surface of the drive cam;
A second recess and a second protrusion are formed on the circumferential surface of the adjustment cam,
When the drive shaft rotates within an angle range between a first angle and a second angle, a first torque acts on the drive shaft due to movement of the first cam follower, a second torque acts on the drive shaft due to movement of the second cam follower, one of the first torque and the second torque is a torque in the same direction as a torque acting on the drive shaft by the biasing force of the energy storage spring, and the other is a torque in an opposite direction to a torque acting on the drive shaft by the biasing force of the energy storage spring, and the first cam follower, the second cam follower, the first recess, the first convex portion, the second recess, and the second convex portion are arranged such that a magnitude of the first torque and a magnitude of the second torque are the same throughout the entire angle range, and the first torque and the second torque cancel each other out.
Tap changer. The energy storage mechanism includes:
a first spring receiving member attached to the other end of the first lever;
A support portion extending along the drive shaft;
a second lever having one end rotatably connected to the support portion and extending in a radial direction of the drive shaft;
a second spring receiving member attached to the other end of the second lever;
a rotation mechanism for rotating the second lever,
The tap changer of claim 1 , wherein the energy storage spring is connected to the first spring receiving member and the second spring receiving member. The rotation mechanism includes:
A rotating member that rotates about an axis parallel to the drive shaft;
a third lever extending from the rotating member in a radial direction of the drive shaft;
The tap changer according to claim 2 , further comprising: a fourth lever extending in a radial direction of the drive shaft and connected to the third lever and the second lever. The tap changer according to claim 1 , wherein a position of the first recess is different from a position of the second recess about the drive shaft. a position of at least a part of the first convex portion is the same as a position of the second concave portion around the drive shaft,
The tap changer according to claim 1 , wherein a position of at least a part of the second convex portion is the same as a position of the first concave portion around the drive shaft.

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