An electric vehicle charging pile fault diagnosis device and diagnosis method

Abstract

The present invention provides an electric vehicle charging pile fault diagnosis device and a diagnosis method. The diagnosis device includes a diagnosis host. A switching connector is embedded on one side end face of the diagnosis host. The switching connector includes a connector housing. An assembly shaft is arranged at the center of the connector housing. A connector assembly ring is sleeved on the assembly shaft. A plurality of square grooves are evenly formed in the outer wall of the connector assembly ring along the circumferential direction of the axis. Connectors are embedded in the square grooves. A plurality of mounting holes penetrating through to the inner wall of the connector assembly ring are spacedly arranged at the bottom of the square grooves. A contact is arranged at the end of the mounting hole. A docking rod connecting the contact and the connector is arranged inside the mounting hole. A transmission protection plate is embedded at one end of the assembly shaft. A transmission wiring board is arranged at the outer end of the transmission protection plate. A plurality of transmission connecting rods are arranged inside the transmission wiring board. The transmission connecting rods extend from the outer end of the transmission protection plate to the outer wall of the transmission protection plate and are movably connected with the contacts. The present invention can provide a variety of connector selections, which are practical, flexible and convenient; at the same time, the fault diagnosis effect is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicle charging piles, and particularly relates to a fault diagnosis device and a diagnosis method for an electric vehicle charging pile. Background Art

[0002] With the rapid development of technology and the increasing awareness of environmental protection among people, more and more electric vehicles are favored by people. As an important supporting device for electric vehicles, charging piles have also emerged. With more and more charging piles put into use, how to confirm the cause of the failure when the charging pile fails for timely maintenance has also become an important research method in the topic of ensuring the operation quality of charging piles.

[0003] When the existing detection and diagnosis equipment is in use, the joints of the detection lines are relatively fixed. Since there are many charging pile manufacturers and the types and models of detections are very different, it will cause the phenomenon that the detection cannot be carried out due to the mismatch of the joints during detection. It is necessary to equip a variety of detection devices or detection adapter cables, which is rather inconvenient. Moreover, when the existing technology is in use, during the use process of the equipment, when the detection joint is not in use, it is basically in a bare state. When the equipment is in a relatively humid, dirty or dusty place, it is easy to have situations such as poor contact caused by dirt at the interface, and thus it is easy to have dangers such as overheating and electric leakage. Summary of the Invention

[0004] The purpose of the present invention is to provide a fault diagnosis device and a diagnosis method for an electric vehicle charging pile, so as to solve the technical problems such as joint mismatch or poor joint contact existing in the use of the existing charging pile detection and diagnosis equipment.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides an electric vehicle charging pile fault diagnosis device, including a diagnostic host, a switchable connector is embedded on one end face of the diagnostic host, the switchable connector includes a connector shell, the front side of the connector shell penetrates to the outer surface of the diagnostic host and is provided with a connector slot, and a protective cover is hinged on the upper side of the connector slot; an assembly shaft is arranged at the center of the connector shell, both ends of the assembly shaft penetrate to the outside of the connector shell and are fixed to the inner surface of the diagnostic host by fasteners; a connector assembly ring is sleeved on the assembly shaft, and the outer wall of the connector assembly ring is uniformly opened along the circumference of the axis centerline A plurality of square grooves are provided, in which joints are embedded, a plurality of mounting holes penetrating to the inner wall of the joint assembly ring are arranged at intervals at the bottom of the square grooves, contacts are arranged at the ends of the mounting holes, and docking rods for connecting the contacts and the joints are arranged on the inner side of the mounting holes; a transmission guard plate is embedded at one end of the assembly shaft, a transmission wiring board is arranged at the outer end of the transmission guard plate, a plurality of transmission connecting rods are arranged on the inner side of the transmission wiring board, the transmission connecting rods extend along the outer end of the transmission guard plate to the outer wall of the transmission guard plate, and each of the transmission connecting rods is arranged corresponding to a contact on each docking head.

[0007] Optionally, a locking device for locking the joint assembly ring is provided at one end of the joint assembly ring, and the locking device includes a locking assembly ring arranged at the end of the joint assembly ring, and a plurality of first fixed magnets are respectively arranged on the outer side of the locking assembly ring corresponding to the joint, and a plurality of second fixed magnets are respectively arranged on the inner wall of the joint shell corresponding to the first fixed magnets.

[0008] Optionally, the contact includes a compression spring and an energized contact piece, the front side of the energized contact piece presents an arc surface corresponding to the outer wall of the assembly shaft, and the rear side of the energized contact piece is connected to the docking rod through the compression spring.

[0009] In a second aspect, the present invention provides a diagnostic method for the above-mentioned electric vehicle charging pile fault diagnostic device, comprising:

[0010] Open the protective cover and move the connector assembly ring until the connector required by the current charging pile reaches the connector slot;

[0011] Connect the current charging pile to the connector and diagnose the current charging pile through the diagnostic host;

[0012] Obtain diagnostic results and obtain the fault risk level based on an integrated evaluation algorithm.

[0013] Optionally, the diagnosing the current charging pile includes:

[0014] Get the health of the charging module H1:

[0015]

[0016] Among them, m1 is the number of times the temperature in the charging pile is too high, α1 is the overcharging influence coefficient, β is the fault influence coefficient, m is the number of fault detections, t(n) is the total charging time after charging n times, T is the working temperature in the charging pile, T0 is the ideal working temperature in the charging pile, γ is the charging influence coefficient, and λ is the temperature influence coefficient;

[0017] Obtain the health degree H2 of the charging gun:

[0018]

[0019] Among them, N1 is the rated plugging and unplugging times of the charging gun, n1 is the actual plugging and unplugging times of the charging gun, n2 is the number of faults of the charging gun, and α2 is the fault influence coefficient;

[0020] Obtain the health degree H3 of the insulating material:

[0021]

[0022] Among them, k is the aging rate constant, t is the number of days the charging pile has been used, α3 is a constant independent of the test conditions of the insulating material, b is the high-temperature influence factor, and n3 is the number of high-temperature days;

[0023] Obtain the communication health status degree H4:

[0024]

[0025] Among them, c is the fault influence coefficient, n4 is the accumulated number of communication faults, and N2 is the rated allowable number of faults of a newly manufactured charging pile;

[0026] Obtain the health degree H5 of the exhaust fan:

[0027]

[0028] Among them, n5 is the actual rotation speed of the exhaust fan, n0 is the rated rotation speed of the exhaust fan, α is the failure rate of the exhaust fan, T is the working temperature in the charging pile, T0 is the ideal working temperature in the charging pile, β1 is the natural aging coefficient of the exhaust fan, and t1 is the number of charging times.

[0029] Optionally, the obtaining the diagnostic result and obtaining the fault risk level based on the integrated evaluation algorithm includes:

[0030] Obtain the health degree H1 of the charging module, the health degree H2 of the charging gun, the health degree H3 of the insulating material, the communication health status degree H4, and the health degree H5 of the exhaust fan, and construct a comprehensive health evaluation index set U, U = {H1, H2, H3, H4, H5};

[0031] Use the analytic hierarchy process to construct a judgment matrix and perform a consistency test, and calculate the eigenvector of the judgment matrix as the weight vector W;

[0032] Five evaluation levels are preset, and a corresponding evaluation list for a single health degree is formulated based on the evaluation levels;

[0033] Based on the comprehensive health evaluation index set U, the corresponding evaluation result R of the single health degree is found according to the corresponding evaluation list of the single health degree;

[0034] Based on the weight vector W, the corresponding evaluation result R of the single health degree, and the score vector S of the preset evaluation levels, the integrated evaluation score f of the charging pile health is obtained:

[0035] f = W × R × S T

[0036] According to the integrated evaluation score f of the charging pile health and the risk score table of the preset evaluation levels, the evaluation level of the fault is obtained.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] The present invention provides an electric vehicle charging pile fault diagnosis device and a diagnosis method. Through the design of a switching joint, when the device is in use, different joints can be switched by rotating the joint assembly ring, eliminating the inconvenience of preparing multiple devices and multiple patch cords, etc., and at the same time ensuring the stability of the wiring and improving the accuracy of diagnosis; the diagnosis method first evaluates the health degree of the core module of the charging pile body, and then comprehensively analyzes the health degrees of each module to obtain the health degree of the entire charging state, thereby realizing the fault judgment of the charging pile body. Description of the Drawings

[0039] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0040] Figure 1 is the outer side schematic diagram of the electric vehicle charging pile fault diagnosis device provided by the embodiment of the present invention;

[0041] Figure 2 is the cross-sectional schematic diagram of the switching joint provided by the embodiment of the present invention;

[0042] Figure 3 is another cross-sectional schematic diagram of the switching joint provided by the embodiment of the present invention;

[0043] Figure 4 is provided by the embodiment of the present invention Figure 2 The enlarged schematic diagram of part A in;

[0044] Figure 5 is the unfolded schematic diagram of the joint assembly ring provided by the embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram of the deployment of the assembly shaft provided by the embodiment of the present invention;

[0046] The markings in the figure are:

[0047] 1. Diagnostic host, 2. Switching joint, 21. Joint housing, 211. Joint slot, 212. Cover, 22. Assembly shaft, 23. Joint assembly ring, 231. Square groove, 232. Joint, 233. Mounting hole, 234. Contact, 235. Docking rod, 236. Compression spring, 237. Energized contact piece, 24. Transmission guard plate, 241. Transmission wiring board, 242. Transmission connecting rod, 25. Locking device, 251. Locking assembly ring, 252. First fixed magnet, 253. Second fixed magnet. Specific embodiments

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1:

[0050] As Figure 1-6 shown, this embodiment provides a fault diagnosis device for an electric vehicle charging pile, including a diagnostic host 1. A switching joint 2 is embedded on one side end face of the diagnostic host 1. The switching joint 2 includes a joint housing 21. The front side of the joint housing 21 penetrates to the outer surface of the diagnostic host 1 and is provided with a joint slot 211. A cover 212 is hinged above the joint slot 211; when in use, the cover 212 needs to be opened for electrical connection from the joint slot 211, and the cover 212 plays a protective role for the inner joint 232 to avoid problems such as damage and poor contact.

[0051] An assembly shaft 22 is provided at the center of the connector housing 21, and both ends of the assembly shaft 22 penetrate the outside of the connector housing 21 and are fixed to the inner surface of the diagnostic host 1 through fasteners; a connector assembly ring 23 is sleeved on the assembly shaft 22, and a plurality of square grooves 231 are evenly opened on the outer wall of the connector assembly ring 23 along the circumference of the axis center line, and a connector 232 is embedded in the square groove 231, and a plurality of mounting holes 233 penetrating the inner wall of the connector assembly ring 23 are arranged at intervals at the bottom of the square groove 231, and contacts 23 are arranged at the ends of the mounting holes 233. 4. A docking rod 235 for connecting the contact 234 and the connector 232 is arranged on the inner side of the mounting hole 233; a transmission guard plate 24 is embedded in one end of the assembly shaft 22, a transmission wiring board 241 is arranged on the outer end of the transmission guard plate 24, and a plurality of transmission connecting rods 242 are arranged on the inner side of the transmission wiring board 241. The transmission connecting rods 242 extend along the outer end of the transmission guard plate 24 to the outer wall of the transmission guard plate 24, and each transmission connecting rod 242 is arranged corresponding to a contact 234 on each docking connector 232.

[0052] In order to ensure that the joint assembly ring 23 can rotate and fix freely, a locking device 25 for locking the joint assembly ring 23 is provided at one end of the joint assembly ring 23, and the locking device 25 includes a locking assembly ring 251 arranged at the end of the joint assembly ring 23, and a plurality of first fixed magnets 252 are arranged on the outer side of the locking assembly ring 251 corresponding to the joint 232, and a plurality of second fixed magnets 253 are arranged on the inner wall of the joint housing 21 corresponding to the first fixed magnets 252; when rotated to a suitable position, it is adsorbed and fixed by the first fixed magnets 252 and the second fixed magnets 253, and when rotation is required, it only needs to manually overcome the magnetic force.

[0053] In order to ensure the tight contact between the contact 234 and the transmission connecting rod 242 to ensure the conductive performance, the contact 234 includes a compression spring 236 and an energized contact piece 237. The front side of the energized contact piece 237 is an arc surface corresponding to the outer wall of the assembly shaft 22, and the rear side of the energized contact piece 237 is connected to the docking rod 235 through the compression spring 236.

[0054] Embodiment 2:

[0055] Based on the electric vehicle charging pile fault diagnosis device described in Example 1, this embodiment proposes a diagnosis method, including the following steps:

[0056] S1. Open the protective cover and move the connector assembly ring until the connector required by the current charging pile reaches the connector slot.

[0057] S2. Connect the current charging pile to the connector and diagnose the current charging pile through the diagnostic host.

[0058] Diagnosis of the current charging pile includes:

[0059] Get the health of the charging module H1:

[0060]

[0061] Among them, m1 is the number of times of excessive temperature inside the charging pile, α1 is the overcharging influence coefficient, initially selected as 0.01, which can be corrected according to the actual influence degree later; β is the fault influence coefficient, initially selected as 0.05, which can be corrected according to the actual influence degree later; m is the number of fault detections, t(n) is the total charging time after charging n times, T is the working temperature inside the charging pile, T0 is the ideal working temperature inside the charging pile, initially selected as 45°C; γ is the charging influence coefficient, initially taken as 0.001; λ is the temperature influence coefficient, initially taken as 10;

[0062] The health of the charging gun is related to the aging degree of the charging gun. Among them, excessive plugging and unplugging and overcharging times of the charging gun will both exacerbate the aging degree of the charging gun. Obtain the health H2 of the charging gun:

[0063]

[0064] Among them, N1 is the rated plugging and unplugging times of the charging gun (if there is no rated plugging and unplugging times at the factory, an appropriate value can be set and corrected according to the empirical value later), n1 is the actual plugging and unplugging times of the charging gun (the actual charging record times of the charging pile), n2 is the number of faults of the charging gun (which can provide reference for the charging gun manufacturer to select), α2 is the fault influence coefficient, initially selected as 0.01, which can be corrected according to the actual influence degree later;

[0065] Obtain the health H3 of the insulating material:

[0066]

[0067] Among them, k is the aging rate constant, taken as 0.018, t is the number of days the charging pile is used, α3 is a constant independent of the insulating material test conditions, initially selected as 0.64, which can be corrected according to the actual influence degree later; b is the high-temperature influence factor, initially selected as 0.001, which can be corrected according to the actual influence degree later; n3 is the number of high-temperature days, and the high temperature can be preset according to needs;

[0068] Obtain the communication health status H4:

[0069]

[0070] Among them, c is the fault influence coefficient, n4 is the accumulated number of communication faults, and N2 is the rated allowable number of faults of the newly produced charging pile, taken as 15 times;

[0071] Obtain the health H5 of the exhaust fan:

[0072]

[0073] Among them, n5 is the actual rotation speed of the exhaust fan, n0 is the rated rotation speed of the exhaust fan, which is taken as 4000, α is the failure rate of the exhaust fan, which is taken as 0.3 (can be corrected according to the actual influence degree later), T is the working temperature inside the charging pile, T0 is the ideal working temperature inside the charging pile, which is taken as 45°C; β1 is the natural aging coefficient of the exhaust fan, which is taken as 0.01, and t1 is the number of charging times.

[0074] S3. Obtain the diagnostic result and get the fault risk level based on the integrated evaluation algorithm.

[0075] Obtaining the fault risk level specifically includes:

[0076] 1. Obtain the health degree H1 of the charging module, the health degree H2 of the charging gun, the health degree H3 of the insulating material, the health status degree H4 of communication, and the health degree H5 of the exhaust fan, and construct a comprehensive health evaluation index set U, U = {H1, H2, H3, H4, H5};

[0077] 2. Use the analytic hierarchy process to construct a judgment matrix and conduct a consistency test.

[0078] The judgment matrix is expressed as:

[0079]

[0080] Among them, a ij represents the comparison result of the i-th factor relative to the j-th factor, and its meaning can be determined according to Table 1:

[0081] Table 1:

[0082] Scale Meaning 1 Indicates that when two factors are compared, they have the same importance 3 Indicates that when two factors are compared, one factor is slightly more important than the other 5 Indicates that when two factors are compared, one factor is significantly more important than the other 7 Indicates that when two factors are compared, one factor is strongly more important than the other 9 Indicates that when two factors are compared, one factor is extremely more important than the other 2,4,6,8 The median of the above two adjacent judgments Reciprocal <![CDATA[Judgment a for comparing factor i and j ij , then judgment a for comparing factor j and i ji = 1 / a ij >

[0083] Consistency test: The consistency test is a process of testing the judgment matrix A by using the consistency index and the consistency ratio < 0.1 and the numerical table of the random consistency index.

[0084] Consistency index CI:

[0085] a) CI = 0, there is complete consistency;

[0086] b) CI is close to 0, there is satisfactory consistency;

[0087] c) The larger CI is, the more serious the inconsistency is.

[0088] To measure the size of CI, the random consistency index RI is introduced, and the value of RI can be determined by Table 2 below, where n is the order of A.

[0089] Table 2:

[0090] n 1 2 3 4 5 6 7 8 9 RI 0 0 0.58 0.9 1.12 1.24 1.32 1.41 1.45

[0091] 3) Define the consistency ratio

[0092] Consistency ratio When, it is considered that the degree of inconsistency of the judgment matrix A is within the allowable range, with satisfactory consistency and passing the consistency test.

[0093] 3. Calculate the eigenvector of the judgment matrix as the weight vector W;

[0094] Use the normalized eigenvector of the judgment matrix A that meets the requirements of the consistency test as the weight vector W, W = [W1, W2, W3, W4, W5], where W i is the weight value of each index;

[0095] 4. Preset five evaluation levels, and formulate a corresponding evaluation list for a single health degree based on the evaluation levels, as shown in Table 3:

[0096]

[0097] For example, if the single input health degree of a charging pile is 85%, then the corresponding sequence r1 = [0.7 0.1 0.1 0.1 0]

[0098] Use the comprehensive health evaluation index set U to find the corresponding evaluation result R of the single health degree based on the corresponding evaluation list of the single health degree;

[0099]

[0100] 5. Based on the weight vector W, the corresponding evaluation result R of the single health degree, and the score vector S of the preset evaluation levels, obtain the integrated health evaluation score f of the charging pile:

[0101] f = W × R × S T

[0102] According to the integrated health evaluation score f of the charging pile and the risk score table of the preset evaluation levels, obtain the evaluation level of the fault.

[0103] The score vector S of the evaluation level and the risk score table are shown in Table 4:

[0104] Table 4:

[0105] S Level Score 100 Absolutely safe 90> 90 Safe 80-90 80 Average 70-80 70 Fault 60-70 60 Fault <60

[0106] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A diagnostic method for a fault diagnosis device of an electric vehicle charging pile, characterized in that, Including: Open the protective cover and turn the connector assembly ring until the connector required by the current charging pile reaches the connector slot; Connect the current charging pile to the connector and diagnose the current charging pile through the diagnostic host; Obtain the diagnostic result and get the fault risk level based on the integrated evaluation algorithm; Among them, the diagnosing the current charging pile includes: Obtain the health degree H1 of the charging module: Among them, m1 is the number of times of over-high temperature in the charging pile, α1 is the overcharging influence coefficient, β is the fault influence coefficient, m is the number of fault detections, t(n) is the total charging time after charging n times, T is the working temperature in the charging pile, T0 is the ideal working temperature in the charging pile, γ is the charging influence coefficient, and λ is the temperature influence coefficient; Obtain the health degree H2 of the charging gun: Among them, N1 is the rated plugging and unplugging times of the charging gun, n1 is the actual plugging and unplugging times of the charging gun, n2 is the number of faults of the charging gun, and α2 is the fault influence coefficient; Obtain the health degree H3 of the insulating material: Among them, k is the aging rate constant, t is the number of days the charging pile is used, α3 is a constant independent of the test conditions of the insulating material, b is the high-temperature influence factor, and n3 is the number of high-temperature days; Obtain the communication health status degree H4: Among them, c is the fault influence coefficient, n4 is the accumulated number of communication faults, and N2 is the rated allowable number of faults of the newly manufactured charging pile; Obtain the health degree H5 of the exhaust fan: Among them, n5 is the actual rotation speed of the exhaust fan, n0 is the rated rotation speed of the exhaust fan, α is the failure rate of the exhaust fan, T is the working temperature in the charging pile, T0 is the ideal working temperature in the charging pile, β1 is the natural aging coefficient of the exhaust fan, and t1 is the number of charging times.

2. The diagnostic method of a fault diagnosis device for an electric vehicle charging pile according to claim 1, wherein, The obtaining the diagnostic result and getting the fault risk level based on the integrated evaluation algorithm includes: Obtain the health degree H1 of the charging module, the health degree H2 of the charging gun, the health degree H3 of the insulating material, the communication health status degree H4, and the health degree H5 of the exhaust fan, and construct a comprehensive health evaluation index set U, U = {H1, H2, H3, H4, H5}; Use the analytic hierarchy process to construct a judgment matrix and conduct a consistency test, and calculate the eigenvector of the judgment matrix as the weight vector W; Preset five evaluation grades and formulate a corresponding evaluation list for a single health degree based on the evaluation grades; Use the comprehensive health evaluation index set U to find the corresponding evaluation result R of a single health degree based on the corresponding evaluation list of a single health degree; Obtain the integrated health evaluation score f of the charging pile based on the weight vector W, the corresponding evaluation result R of a single health degree, and the score vector S of the preset evaluation grades; f = W × R × S T Obtain the evaluation grade of the fault according to the integrated health evaluation score f of the charging pile and the risk score table of the preset evaluation grades.

3. The diagnostic method of a fault diagnosis device for an electric vehicle charging pile according to claim 1, characterized in that The electric vehicle charging pile fault diagnosis device includes a diagnostic host, and a switching connector is embedded on one end face of the diagnostic host, The switching connector includes a connector housing, the front side of the connector housing penetrates to the outer surface of the diagnostic host and is provided with a connector slot, and a protective cover is hinged on the upper side of the connector slot; An assembly shaft is arranged at the center of the connector housing, and both ends of the assembly shaft penetrate to the outside of the connector housing and are fixed on the inner surface of the diagnostic host through fasteners; A joint assembly ring is sleeved on the assembly shaft. A plurality of square grooves are evenly formed in the circumferential direction of the outer wall of the joint assembly ring along the axis. A joint is embedded in each square groove. A plurality of mounting holes penetrating through the inner wall of the joint assembly ring are spaced apart at the bottom of the square groove. A contact is arranged at the end of each mounting hole, and a docking rod connecting the contact and the joint is arranged inside each mounting hole. A transmission guard plate is embedded at one end of the assembly shaft. A transmission wiring board is arranged at the outer end of the transmission guard plate. A plurality of transmission connecting rods are arranged inside the transmission wiring board. The transmission connecting rods extend from the outer end of the transmission guard plate to the outer wall of the transmission guard plate, and each transmission connecting rod is correspondingly arranged with one contact on each joint.

4. The diagnostic method of a fault diagnosis device for an electric vehicle charging pile according to claim 3, characterized in that, A locking device for locking the joint assembly ring is arranged at one end of the joint assembly ring. The locking device includes a locking assembly ring arranged at the end of the joint assembly ring. A plurality of first fixed magnets are respectively arranged on the outer side of the locking assembly ring corresponding to the joints, and a plurality of second fixed magnets are arranged on the inner wall of the joint housing corresponding to the first fixed magnets.

5. The diagnostic method of a fault diagnosis device for an electric vehicle charging pile according to claim 3, characterized in that, The contact includes a compression spring and an energized contact piece. The front side of the energized contact piece is an arc surface corresponding to the outer wall of the assembly shaft, and the rear side of the energized contact piece is connected to the docking rod through the compression spring.

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