Cam timing drive mechanism of bridge-arm type on-load voltage regulating device

Abstract

The utility model relates to a cam timing drive mechanism of bridge arm type on -load voltage regulating device for driving bridge arm type on -load voltage regulating device's mechanical switch group, including drive motor, main shaft and cam drive mechanism, main shaft is connected with drive motor transmission, every mechanical switch group is connected with cam drive mechanism, and cam drive mechanism includes cam, pole lever, insulating push subassembly and reset spring, a plurality of cams are coaxially arranged in sequence along the main shaft axial direction, and the one end of pole lever is rolled with cam outer contour cooperation, and the other end is through insulating push subassembly transmission connection contact switch, the contour curve and the installation angle phase of every cam are according to preset timing setting, under the rotation drive of main shaft, the plurality of cams connected with same mechanical switch group pushes corresponding pole lever in sequence in different angular position, makes corresponding contact switch according to preset timing disconnects or closes. The utility model adopts pure mechanical structure to realize contact switch action timing control, guarantees the security and reliability of voltage regulating switching process.

Description

Technical Field

[0001] This utility model belongs to the field of on-load tap changer technology for power equipment, specifically relating to a cam timing drive mechanism for a bridge-arm type on-load tap changer. Background Technology

[0002] The bridge-arm type on-load tap changer combines different potentials of the multi-tap tapping winding through the upper and lower bridge arm switch groups to achieve multi-stage voltage regulation of the transformer under load. During the switching between adjacent taps, a transition switch is also provided to provide a temporary closed current path to ensure continuous current on the load side.

[0003] During the voltage regulation switching process of a bridge-arm type on-load tap changer, the operation of each bridge arm switch and transition switch must follow specific timing requirements: the new position bridge arm switch must close before the old position bridge arm switch opens, i.e., close before open; the transition switch must be turned on and off at the appropriate time when the bridge arm switch is switching, and multiple bridge arm switches are not allowed to be turned on simultaneously within the same bridge arm, i.e., internal interlocking within the bridge arm. The above timing and interlocking requirements are the basic conditions for the safe operation of a bridge-arm type on-load tap changer.

[0004] In existing technologies, the timing and interlocking relationships of bridge arm switches are mainly guaranteed by electrical control logic, that is, the controller issues action commands to each switch sequentially according to a preset program. However, the use of electrical control has the following problems: on the one hand, hardware or software failures of the controller may lead to timing errors or interlocking failures, posing a risk of multiple switches in the same bridge arm switch group being turned on simultaneously; on the other hand, the lack of physical linkage constraints between the independent drive mechanisms of each switch means that even if the control signal is correct, differences in the response time of each switch drive mechanism may cause the actual action timing to deviate from the design requirements.

[0005] Therefore, it is necessary to provide a timing linkage drive mechanism with a clear physical structure to realize the action timing control and internal interlocking of the switch group from a purely mechanical level, so as to ensure the safety and reliability of the voltage regulation switching process. Utility Model Content

[0006] To address the aforementioned problems in the existing technology, this utility model provides a cam timing drive mechanism for a bridge-type on-load tap changer. By sequentially actuating the contact switches in each mechanical switch group through multiple cam drive mechanisms, the timing control of the action of each contact switch is achieved using a purely mechanical structure, thereby improving the safety and reliability of the bridge-type on-load tap changer during the tap change process.

[0007] The technical problem to be solved by this utility model is achieved through the following technical solution: This utility model provides a cam timing drive mechanism for a bridge arm type on-load tap changer, used to drive the mechanical switch group of the bridge arm type on-load tap changer. Each mechanical switch group includes at least one contact switch, including: a drive mechanism, a main shaft and a cam drive mechanism. The main shaft is connected to the drive mechanism, and each mechanical switch group is connected to at least one cam drive mechanism. The cam drive mechanism is connected to the contact switch in a one-to-one correspondence. Each of the cam drive mechanisms includes: a cam, a lever, an insulating push assembly, and a return spring; multiple cams are coaxially arranged sequentially along the axial direction of the main shaft; one end of the lever contacts the outer contour of the cam, and the other end is driven to the contact switch through the insulating push assembly; the return spring is mounted on the lever and is used to drive the lever to return to its original position. The contour curve and installation angle phase of each cam are set according to a preset timing sequence. Under the rotation drive of the main shaft, multiple cams push the corresponding levers in sequence at different rotation angle positions, and at any time, at most one contact switch in the same mechanical switch group is closed.

[0008] In one embodiment of this utility model, the output shaft of the drive mechanism is coaxially connected to the main shaft via a coupling, and both ends of the main shaft are supported on the frame by bearing seats.

[0009] In one embodiment of this utility model, the far rest segments of all the cams corresponding to the same mechanical switch group do not overlap at the rotation angle of the main shaft.

[0010] In one embodiment of this utility model, the cam is fixed to the main shaft by means of key connection, interference fit, or integrated connection with the main shaft.

[0011] In one embodiment of this utility model, the cam is a planar disc cam, and the profile curve of each cam includes a base circle segment, a lift segment, a far rest segment, and a return segment that are connected end to end in sequence. The contour curve of the lift segment adopts any one of the following motion laws: constant acceleration, constant deceleration, sinusoidal acceleration, polynomial motion, and trapezoidal acceleration.

[0012] In one embodiment of this utility model, the middle part of the lever is connected to the frame via a hinge shaft, one end of the lever is a transmission end, and the transmission end is in rolling engagement with the corresponding outer contour of the cam via a roller; the other end of the lever is a pushing end, and the pushing end is away from the cam and connected to the insulating pushing assembly; The roller is a cylindrical roller, and the rotation axis of both the hinge shaft and the roller is parallel to the axis of the main shaft.

[0013] In one embodiment of this utility model, the reset spring is a helical compression spring, one end of which is fixed to the frame and the other end is connected to the push end of the lever.

[0014] In one embodiment of this utility model, the insulating push assembly is a rigid rod made of insulating material, one end of the insulating push assembly is hinged to the push end of the lever, and the other end is in contact with the moving contact of the contact switch.

[0015] In one embodiment of this utility model, the drive mechanism is any one of a low-speed, high-torque motor, a hydraulic motor, and a pneumatic motor.

[0016] In one embodiment of this utility model, the mechanical switch group of the bridge arm type on-load tap changer includes an upper bridge arm switch group, a lower bridge arm switch group, and a transition switching switch group. The upper bridge arm switch group is provided with contact switches T1, T2, and T3. The lower bridge arm switch group is provided with contact switches T4, T5, and T6. The transition switching switch group is provided with contact switches K1 and K2. The number of cam drive mechanisms is eight, which are used to drive the contact switches in the upper bridge arm switch group, the lower bridge arm switch group and the transition switching switch group respectively.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model discloses a cam-driven timing mechanism for a bridge-arm type on-load tap changer. It employs multiple cams that rotate synchronously with the main shaft, and sets the contour curves and installation angles of each cam according to a preset switching action sequence. The continuous rotational motion of the main shaft is converted into the reciprocating oscillation of each lever according to a predetermined pattern through the cooperation of the cam's outer contour and the lever. This, in turn, drives the corresponding contact switches to close or open via an insulated push assembly. This structure controls the action sequence and interlocking relationship of each contact switch through the mechanical contour of the cams, achieving a forced constraint on the switching action sequence from a purely mechanical structural level. This eliminates the risk of timing errors and interlocking failures caused by electrical control logic faults or differences in the response time of individual drive mechanisms, significantly improving the safety and reliability of the tap changer switching process.

[0018] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a cam timing drive mechanism for a bridge-arm type on-load pressure regulating device provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the cam drive mechanism provided in an embodiment of the present utility model; Figure 3 This is a timing diagram showing the relationship between the cam angle phase and the contact switch action provided in this embodiment of the utility model.

[0020] Reference numerals: 1-Drive mechanism; 2-Main shaft; 3-Cam drive mechanism; 31-Cam; 311-Base circle segment; 312-Lift segment; 313-Far rest segment; 314-Return segment; 32-Lever; 321-Connecting rod; 322-Roller; 33-Insulated push assembly; 34-Reset spring; 4-Coupling; 101-Moving contact. Detailed Implementation

[0021] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following detailed description of the cam timing drive mechanism of a bridge arm type on-load pressure regulating device according to this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0022] The foregoing and other technical contents, features, and effects of this utility model will be clearly presented in the following detailed description of the specific embodiments with reference to the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding can be gained of the technical means and effects adopted by this utility model to achieve the intended purpose. However, the accompanying drawings are only provided for reference and illustration and are not intended to limit the technical solution of this utility model.

[0023] Example 1 like Figures 1 to 3 As shown, Figure 1 This is a schematic diagram of a cam timing drive mechanism for a bridge-arm type on-load pressure regulating device provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the cam drive mechanism provided in an embodiment of the present utility model; Figure 3 This is a timing diagram showing the relationship between the cam angle phase and the contact switch action provided in this embodiment of the utility model.

[0024] This embodiment provides a cam timing drive mechanism for a bridge-type on-load tap changer, used to drive the mechanical switch groups of the bridge-type on-load tap changer, each mechanical switch group including at least one contact switch.

[0025] like Figure 1 and Figure 2As shown, the cam timing drive mechanism of the bridge arm type on-load tap changer in this embodiment includes a drive mechanism 1, a main shaft 2 and a cam drive mechanism 3; the main shaft 2 is connected to the drive mechanism 1 in a transmission manner, each mechanical switch group is connected to at least one cam drive mechanism 3, and in the same mechanical switch group, the cam drive mechanism 3 is connected to the contact switch in a one-to-one correspondence.

[0026] In an optional embodiment, the lever 32 includes a connecting rod 321 and a roller 322. The lever 32 is a rigid rod, with its middle portion connected to the frame via a hinge shaft. One end of the lever 32 is a transmission end, which rolls with the outer contour of the corresponding cam 31 via the roller 322. The other end of the lever 32 is a pushing end, which is away from the cam 31 and connected to an insulated pushing assembly 33. Preferably, the roller 322 is a cylindrical roller, and the rotation axes of both the hinge shaft and the roller 322 are parallel to the axis of the main shaft 2. The outer circular surface of the roller 322 contacts the outer contour surface of the corresponding cam 31, and the roller 322 rolls along the outer contour surface of the cam 31 during the rotation of the cam 31. Through the rolling engagement between the roller 322 and the outer contour of the cam 31, the rotational motion of the cam 31 is converted into the oscillating motion of the lever 32 around the hinge shaft, while reducing the frictional resistance between the cam 31 and the lever 32.

[0027] Specifically, each cam drive mechanism 3 includes a cam 31, a lever 32, an insulating push assembly 33, and a return spring 34. Multiple cams 31 are coaxially arranged sequentially along the axial direction of the main shaft 2. The contour curve and installation angle phase of each cam 31 are set according to a preset timing sequence. Driven by the rotation of the main shaft 2, multiple cams 31 sequentially push the corresponding lever 32 at different rotation angles, and at any given time, at most one contact switch within the same mechanical switch group is closed. Furthermore, for the same mechanical switch group, the far rest sections 313 of all corresponding cams 31 do not overlap at the rotation angles of the main shaft 2. In other words, at any angular position of the main shaft 2, at most one cam 31 in the same mechanical switch group has its far rest section 313 in contact with the lever 32, thus ensuring that at most one contact switch within the group is in a closed state.

[0028] Preferably, the cam 31 is a planar disc cam, and the profile curve of each cam 31 includes a base circle segment 311, a lift segment 312, a rest segment 313, and a return segment 314 connected end to end. The base circle segment 311 forms an arc segment with radius r0 centered on the axis of the main shaft 2; the profile curve of the lift segment 312 adopts any one of the following motion laws: constant acceleration, constant deceleration, sinusoidal acceleration, polynomial motion, and trapezoidal acceleration, to ensure smooth movement of the lever 32. Furthermore, the cam 31 is fixed to the main shaft 2 by key connection, interference fit, or integrated connection with the main shaft 2, so that each cam 31 rotates synchronously with the main shaft 2 without relative rotation.

[0029] When the roller 322 of the lever 32 contacts the base circle segment 311, the lever 32 is in its initial position, and the corresponding contact switch is in the open state. The lift segment 312 is a curved segment that gradually transitions from the end of the base circle segment 311 to the far rest segment 313. Its radial distance gradually increases from the base circle radius r0 of the base circle segment 311 to the radius r0+h, where h is the cam lift. When the roller 322 passes through the lift segment 312, the lever 32 is gradually pushed, causing the corresponding contact switch to transition from the open state to the closed state. The far rest segment 313 is an arc segment with the axis of the main shaft 2 as the center and a radius of r0+h. When the roller 322 contacts the far rest segment 313, the lever 32 is in the maximum extended position, and the corresponding contact switch remains in the closed state. The rotation angle range of the main shaft 2 corresponding to the far rest segment 313 determines the closing duration angle of the contact switch. The return segment 314 is a curved segment that gradually transitions from the end of the far rest segment 313 back to the base circle segment 311, with its radial distance gradually decreasing from r0+h to the base circle radius r0. When the roller 322 passes through the return segment 314, the lever 32 gradually returns to its original position under the action of the return spring 34, driving the corresponding contact switch to transition from the closed state to the open state. Since the base circle radius r0 and lift h of each cam 31 are the same, but the starting angle of the lift segment 312, the angle range occupied by the far rest segment 313, and the starting angle of the return segment 314 of each cam 31 are different, the contour curve of each cam 31 and the installation angle phase of each cam 31 on the main shaft 2 are set by the preset switch action sequence, that is, the deflection angle of the starting angle of the lift segment 312 relative to the reference position of the main shaft 2, so that each cam 31 pushes the corresponding lever 32 in turn at different rotation angle positions during the rotation of the main shaft 2, thereby realizing that each switch operates in sequence according to the predetermined timing.

[0030] Understandably, for different mechanical switch groups, the specific parameters of the corresponding cam drive mechanism 3 can be set to be the same or different, and this embodiment does not impose any restrictions on this.

[0031] In this embodiment, the pushing end of the lever 32 is connected to the contact switch via an insulating pushing assembly 33. The insulating pushing assembly 33 is a rigid rod made of insulating material, one end of which is hinged to the pushing end of the lever 32, and the other end is in contact with the moving contact 101 of the contact switch. By transmitting the mechanical movement of the lever 32 to the moving contact 101 of the contact switch through the insulating pushing assembly 33, electrical insulation isolation between the cam drive mechanism 3 and the moving contact 101 is achieved.

[0032] For example, the insulating push assembly 33 may also employ an insulating linkage mechanism or an insulating cam slider mechanism to convert the swing motion of the lever 32 into the linear motion of the moving contact 101 and achieve electrical insulation. This embodiment does not limit this.

[0033] Specifically, when the lifting section 312 or the far rest section 313 of the cam 31 contacts the roller 322, the roller 322 is pushed outward by the cam 31, and the lever 32 swings around its hinge axis. The pushing end of the lever 32 pushes the moving contact 101 of the contact switch towards its stationary contact via the insulating pushing assembly 33, so that the moving contact 101 contacts and closes with the stationary contact, making the contact switch conduct. When the base circle section 311 of the cam 31 contacts the roller 322, the pushing force of the cam 31 on the lever 32 disappears, and the lever 32 returns to its original position under the action of the return spring 34. The pushing end of the lever 32 drives the moving contact 101 away from the stationary contact via the insulating pushing assembly 33, making the contact switch open.

[0034] In an optional embodiment, a return spring 34 is mounted on the lever 32 to drive the lever 32 to reset. Preferably, the return spring 34 is a helical compression spring, one end of which is fixed to the frame and the other end is connected to the push end of the lever 32. The return spring 34 applies an elastic restoring force to the lever 32 to move the push end away from the contact switch.

[0035] Specifically, the return spring 34 is always in a compressed state, applying an elastic restoring force to the lever 32, causing the pushing end of the lever 32 to move away from the contact switch. When the cam 31 pushes the lever 32 in the lift section 312 or the far rest section 313, the return spring 34 is further compressed, storing elastic potential energy; when the cam 31 rotates to the return section 314 or the base circle section 311, the return spring 34 releases the elastic potential energy, pushing the lever 32 back to its original position, causing the contact switch to open. By providing the restoring force to open the contact switch through the return spring 34, it is ensured that the contact switch can reliably open within the angle range corresponding to the return section 314 and the base circle section 311; at the same time, it ensures that the roller 322 always maintains contact with the outer contour surface of the cam 31 and does not disengage.

[0036] In this embodiment, the output shaft of the drive mechanism 1 is coaxially connected to the main shaft 2 via a coupling 4, and both ends of the main shaft 2 are supported on the frame by bearing seats.

[0037] Preferably, the drive mechanism 1 is any one of an electric motor, a hydraulic motor, and a pneumatic motor, used to provide the driving torque required for the rotation of the spindle 2.

[0038] Preferably, the coupling 4 is a flexible coupling, used to compensate for the axial deviation between the output shaft of the drive mechanism 1 and the main shaft 2, while transmitting torque.

[0039] In one optional embodiment, a rolling bearing is installed in the bearing housing, allowing the main shaft 2 to rotate freely within the bearing housing, while the mechanical switch groups in the bridge-arm type on-load tap changer are arranged sequentially along the axial direction of the main shaft 2.

[0040] Furthermore, the contour curve and installation angle of each cam 31 are set according to a preset timing sequence. After the cam 31 is machined and installed, the starting angle of the lift segment 312, the angle range of the far rest segment 313, and the starting angle of the return segment 314 of each cam 31 are fixed in the mechanical structure. Driven by the rotation of the main shaft 2, multiple cams 31 connected to the same mechanical switch group push the corresponding lever 32 in sequence at different rotation angle positions, thereby causing the corresponding contact switch to open or close according to the preset timing sequence through the insulating push assembly 33.

[0041] The cam-driven timing mechanism of this utility model's bridge-arm type on-load tap changer uses multiple cams 31 that rotate synchronously with the main shaft 2. The contour curves and installation angles of each cam 31 are set according to a preset switching action sequence. The continuous rotation of the main shaft 2 is converted into the reciprocating oscillation of each lever 32 according to a predetermined pattern by the cooperation of the outer contour of the cam 31 and the lever 32. This, in turn, drives the corresponding contact switches to close or open via the insulated push assembly 33. This structure controls the action sequence and interlocking relationship of each contact switch through the mechanical contour of the cam 31. It achieves forced constraint on the switching action sequence from a purely mechanical structural level, eliminating the risk of timing errors and interlocking failures caused by electrical control logic faults or differences in the response time of individual drive mechanisms, significantly improving the safety and reliability of the tap changer switching process.

[0042] Example 2 This embodiment is based on Embodiment 1, and combines... Figure 3 The timing relationship between the cam angle phase and the contact switch action is shown. Taking a specific gear switching process as an example, this paper further illustrates the specific working principle of the cam timing drive mechanism of this utility model to realize the timing of the first engagement and then disengagement and the internal interlocking of the bridge arm.

[0043] In this embodiment, the mechanical switch group of the bridge arm type on-load tap changer includes an upper bridge arm switch group, a lower bridge arm switch group, and a transition switching switch group; the contact switches include: contact switch T1, contact switch T2, and contact switch T3; contact switch T4, contact switch T5, and contact switch T6; contact switch K1 and contact switch K2, wherein the upper bridge arm switch group is provided with contact switch T1, contact switch T2, and contact switch T3, the lower bridge arm switch group is provided with contact switch T4, contact switch T5, and contact switch T6, and the transition switching switch group is provided with contact switch K1 and contact switch K2. There are eight cam drive mechanisms 3. Each cam drive mechanism 3 includes a cam 31, a lever 32, an insulating push assembly 33, and a return spring 34. The eight cams 31 are arranged sequentially and spaced apart along the axis of the main shaft 2, namely the first cam C1, the second cam C2, the third cam C3, the fourth cam C4, the fifth cam C5, the sixth cam C6, the seventh cam C7, and the eighth cam C8, which respectively drive the first lever L1 to the eighth lever L8, and then drive the contact switches in the upper bridge arm switch group, the lower bridge arm switch group, and the transition switching switch group.

[0044] The following example illustrates the principle of cam 31's angle phase setting and timing implementation principle using a bridge arm type on-load tap changer, where the upper bridge arm switch group has contact switch T1 and the lower bridge arm switch group has contact switch T6, and the switch switches have T2 and T6 have contact switches.

[0045] During the switching process, the upper bridge arm switch group switches from contact switch T1 being on to contact switch T2 being on, while contact switch T6 in the lower bridge arm switch group remains on. At this time, contact switch K1 is first closed to establish a transition path, then contact switch T2 is closed to connect the upper bridge arm switch of the new gear, then contact switch T1 is opened to deactivate the upper bridge arm switch of the old gear, and finally contact switch K1 is opened to exit the transition path.

[0046] To achieve the above timing sequence, the cams 31 corresponding to each contact switch have the following installation angle phase relationship on the main shaft 2: the starting angle of the lift segment 312 of the seventh cam C7 corresponding to contact switch K1 is the smallest, that is, during the rotation of the main shaft 2, the seventh cam C7 enters the lift segment 312 first, causing contact switch K1 to close first; the starting angle of the lift segment 312 of the second cam C2 corresponding to contact switch T2 is greater than the starting angle of the lift segment 312 of the seventh cam C7, but less than the starting angle of the return segment 314 of the first cam C1 corresponding to contact switch T1, so that contact switch T2 is closed first. After contact switch K1 is closed, it closes before contact switch T1 is opened; the starting angle of the return segment 314 of the first cam C1 corresponding to contact switch T1 is greater than the starting angle of the lift segment 312 of the second cam C2 plus the angle occupied by the lift segment 312, so that contact switch T1 only starts to open after contact switch T2 is fully closed; the starting angle of the return segment 314 of the seventh cam C7 corresponding to contact switch K1 is greater than the starting angle of the return segment 314 of the first cam C1 plus the angle occupied by the return segment 314, so that contact switch K1 only starts to open after contact switch T1 is fully open.

[0047] By designing the profile curve and installation angle phase of cam 31, within a specific angle range of spindle 2 rotation, each contact switch operates in strict accordance with the timing sequence of contact switch K1 closing - contact switch T2 closing - contact switch T1 opening - contact switch K1 opening, thus realizing the switching sequence of closing first and then opening.

[0048] Meanwhile, the internal interlocking of the bridge arm is achieved in the following way: In the upper bridge arm switch group, the far rest sections 313 of the first cam C1 corresponding to contact switch T1, the second cam C2 corresponding to contact switch T2, and the third cam C3 corresponding to contact switch T3 do not overlap at the rotation angle of the main shaft 2. That is, at any rotation angle position of the main shaft 2, at most one of the three cams 31 in the same mechanical switch group is in the far rest section 313, and the remaining cams 31 are all in the base circle section 311. This means that at any given time, at most one of the three contact switches in the upper bridge arm switch group is in the closed state, and the rest are in the open state, thus achieving the internal interlocking of the upper bridge arm switch group at the purely mechanical structure level. Similarly, the internal interlocking of each contact switch in the lower bridge arm switch group is also achieved by the far rest sections 313 of the corresponding cams 31 not overlapping at the rotation angle of the main shaft 2.

[0049] It is worth noting that the above interlocking relationship is determined by the geometry of the profile curve of cam 31 and the phase of the installation angle. Once cam 31 is machined and installed, the interlocking relationship is fixed in the mechanical structure and does not depend on any electrical control logic, so it is not affected by controller failure.

[0050] To enable those skilled in the art to fully understand and implement this utility model, the following example illustrates the dynamic working process of this utility model using a bridge arm type on-load tap changer, where the upper bridge arm switch group has contact switch T1 and the lower bridge arm switch group has contact switch T6, and the switch switches have T2 and T6 have contact switches.

[0051] Spindle 2 is in the initial angle position At this time, the far rest section 313 of the first cam C1 contacts the roller 322 of the first lever L1, the first lever L1 is in the maximum extended position, and the contact switch T1 is in the closed conducting state; the far rest section 313 of the sixth cam C6 contacts the roller 322 of the sixth lever L6, and the contact switch T6 is in the closed conducting state. The remaining cams 31 all have their base circle section 311 in contact with the corresponding roller 322, and the corresponding contact switches are all in the open state. The output voltage of the bridge arm type on-load tap changer is +3U.

[0052] The external voltage regulator controller issues a switching control command, the drive mechanism 1 starts, and drives the spindle 2 to rotate.

[0053] In the first stage, spindle 2 rotates to an angle. The seventh cam C7 begins to contact the roller 322 of the seventh lever L7 at its lift section 312. The seventh lever L7 is gradually pushed out, pushing the moving contact 101 of the contact switch K1 towards its stationary contact via the insulating push assembly 33. When the seventh cam C7 rotates to the far rest section 313, the seventh lever L7 reaches its maximum push-out position, the contact switch K1 is fully closed, and the bridge arm input common node forms a temporary closed path with the upper output bus through the contact switch K1. At this time, the first cam C1 is still in the far rest section 313, and the contact switch T1 remains closed; the sixth cam C6 is still in the far rest section 313, and the contact switch T6 remains closed.

[0054] In the second stage, spindle 2 continues to rotate to the desired angle. The second cam C2 begins to contact the roller 322 of the second lever L2 during its lift phase 312. The second lever L2 is gradually pushed out, pushing the moving contact of the contact switch T2 towards the stationary contact via the insulating push assembly 33. When the second cam C2 rotates to the far rest phase 313, the contact switch T2 is fully closed. At this time, the first cam C1 is still in the far rest phase 313, and the contact switch T1 remains closed; the seventh cam C7 is in the far rest phase 313, and the contact switch K1 remains closed. That is, contact switches T1 and T2 are closed simultaneously, but since contact switch K1 is already conducting, providing a transition path, the brief overlapping conduction state is safe.

[0055] In the third stage, spindle 2 continues to rotate to the specified angle. When the first cam C1 enters the return section 314, the first lever L1 gradually returns to its original position under the action of the return spring 34. Through the insulating push assembly 33, it drives the moving contact 101 of the contact switch T1 to leave the stationary contact, and the contact switch T1 opens. At this time, the second cam C2 is in the far rest section 313, and the contact switch T2 remains closed; the seventh cam C7 is in the far rest section 313, and the contact switch K1 remains closed. The conduction path of the upper bridge arm switches from the contact switch T1 to the contact switch T2.

[0056] In the fourth stage, spindle 2 continues to rotate to the desired angle. When the seventh cam C7 enters the return section 314, the seventh lever L7 returns to its original position under the action of the return spring 34, the contact switch K1 opens, and the transition path exits. At this time, the second cam C2 is in the far rest section 313, and the contact switch T2 remains closed; the sixth cam C6 is in the far rest section 313, and the contact switch T6 remains closed. The bridge-arm type on-load tap changer enters a new steady-state operating state, and the output voltage is +2U.

[0057] In the fifth stage, the main shaft 2 rotates to the predetermined termination angle, the motor stops, and the main shaft 2 remains at the new angular position. At this time, the far rest sections of the second cam C2 and the sixth cam C6 respectively contact the corresponding rollers 322, and the contact switches T2 and T6 remain closed and conductive, and the device operates stably in the +2U position.

[0058] The switching process between other adjacent gears is similar to the process described above, except that the rotation direction or angle of the main shaft 2 is different. This causes different combinations of cams 31 to sequentially enter their lift section 312 and return section 314, driving different bridge arm switch groups and transition switching switch groups to complete their actions according to the corresponding timing sequence. The forward and reverse rotation of the main shaft 2 corresponds to the upshifting and downshifting operations of the pressure regulating gear, respectively. Further details are omitted here.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0060] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A cam-driven timing mechanism for a bridge-arm type on-load tap changer, used to drive mechanical switch groups of the bridge-arm type on-load tap changer, each of the mechanical switch groups including at least one contact switch, characterized in that, include: Drive mechanism, spindle and cam drive mechanism; The main shaft is connected to the drive mechanism, and each mechanical switch group is connected to at least one cam drive mechanism. The cam drive mechanism is connected to the contact switch in a one-to-one correspondence. Each of the cam drive mechanisms includes: a cam, a lever, an insulating push assembly, and a return spring; multiple cams are coaxially arranged sequentially along the axial direction of the main shaft; one end of the lever contacts the outer contour of the cam, and the other end is driven to the contact switch through the insulating push assembly; the return spring is mounted on the lever and is used to drive the lever to return to its original position. The contour curve and installation angle phase of each cam are set according to a preset timing sequence. Under the rotation drive of the main shaft, multiple cams push the corresponding levers in sequence at different rotation angle positions, and at any time, at most one contact switch in the same mechanical switch group is closed.

2. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 1, characterized in that, The output shaft of the drive mechanism is coaxially connected to the main shaft via a coupling, and both ends of the main shaft are supported on the frame by bearing seats.

3. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 1, characterized in that, The far rest segments of all the cams corresponding to the same mechanical switch group do not overlap at the rotation angle of the main shaft.

4. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 1, characterized in that, The cam is fixed to the spindle by means of key connection, interference fit, or integrated connection with the spindle.

5. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 1, characterized in that, The cam is a planar disc cam, and the profile curve of each cam includes a base circle segment, a lift segment, a far rest segment and a return segment connected end to end in sequence. The contour curve of the lift segment adopts any one of the following motion laws: constant acceleration, constant deceleration, sinusoidal acceleration, polynomial motion, and trapezoidal acceleration.

6. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 2, characterized in that, The middle part of the lever is connected to the frame via a hinge shaft. One end of the lever is a transmission end, which rolls with the outer contour of the corresponding cam via a roller. The other end of the lever is a push end, which is away from the cam and connected to the insulated push assembly. The roller is a cylindrical roller, and the rotation axis of both the hinge shaft and the roller is parallel to the axis of the main shaft.

7. The cam-driven timing mechanism of the bridge-arm type on-load pressure regulating device according to claim 6, characterized in that, The reset spring is a helical compression spring, with one end fixed to the frame and the other end connected to the push end of the lever.

8. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 6, characterized in that, The insulating push assembly is a rigid rod made of insulating material. One end of the insulating push assembly is hinged to the push end of the lever, and the other end is in contact with the moving contact of the contact switch.

9. The cam timing drive mechanism of the bridge arm type on-load pressure regulating device according to claim 1, characterized in that, The drive mechanism is any one of an electric motor, a hydraulic motor, and a pneumatic motor.

10. The cam-driven timing mechanism of the bridge-arm type on-load pressure regulating device according to claim 1, characterized in that, The mechanical switch group of the bridge arm type on-load tap changer includes an upper bridge arm switch group, a lower bridge arm switch group, and a transition switching switch group. The upper bridge arm switch group is provided with contact switches T1, T2, and T3. The lower bridge arm switch group is provided with contact switches T4, T5, and T6. The transition switching switch group is provided with contact switches K1 and K2. The number of cam drive mechanisms is eight, which are used to drive the contact switches in the upper bridge arm switch group, the lower bridge arm switch group and the transition switching switch group respectively.

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