A moving contact and contact box assembly for a wind- and sand-resistant auxiliary switch.
By designing wind- and sand-resistant moving contact pieces and contact box assemblies, the problem of poor contact of auxiliary switches in sandy environments was solved, achieving stable and reliable electrical contact and reducing maintenance costs.
Patent Information
- Application Number
- CN202522617962.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-11-06
- Estimated Expiration
- 2035-12-10
AI Technical Summary
Existing auxiliary switches are prone to poor contact due to the adhesion and accumulation of particulate matter in dusty environments, and lack effective sealing and positioning reliability, resulting in signal transmission interruption and local overheating.
Design a wind-resistant moving contact plate, including an arc-shaped contact block, a limiting block and a rotating protrusion, which, together with the contact box assembly, can actively scrape off sand and dust and achieve stable positioning, thereby enhancing the sealing performance.
It effectively removes sand and oxide layers from the contacts, maintains good electrical contact, improves the reliability and stability of the auxiliary switch in sandy environments, and reduces maintenance costs.
Smart Images
Figure CN224946676U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic device technology, and in particular to a moving contact piece and contact box assembly for a wind and sand resistant auxiliary switch. Background Technology
[0002] Auxiliary switches, as core control components of power equipment such as high-voltage circuit breakers and disconnectors, undertake crucial functions such as secondary circuit opening and closing control, signal transmission, and interlocking protection. They are widely used in power plants, indoor and outdoor substations. With the vigorous development of new energy sources, many substations in Northwest China located near wind farms and photovoltaic fields face complex environments with large diurnal temperature variations and strong wind and sand erosion. In these environments, dust concentrations often reach 50 mg / m³. 3 The particle size is mostly between 0.005-0.5mm, and the impact of strong winds and temperature differences of more than 60°C between day and night pose a severe challenge to the reliability of the auxiliary switch.
[0003] The corrosive effects of dusty environments on traditional auxiliary switches are mainly manifested in the failure of the contact system: fine dust particles can penetrate the interior through gaps in the contact box joints and between the front and rear cover plates, adhering to the contact interface between the moving and stationary contacts. These particles can form an insulating layer, causing the contact resistance to soar from the normal milliohm level to hundreds of ohms, leading to signal transmission interruption or localized overheating;
[0004] Existing technologies mostly employ passive protection methods to address the aforementioned problems, but they have significant limitations: First, the sealing structure design is insufficient; traditional auxiliary switches typically only have an IP20 protection rating, which cannot prevent the intrusion of fine sand and dust. Second, there is a lack of active cleaning mechanisms; although the mechanism box has a sealing function, the cabinet door is frequently opened during substation construction and commissioning, making it difficult to ensure complete dust isolation. Third, the moving contact plate has poor positioning stability; traditional structures rely on springs or simple protrusions for limiting, resulting in poor structural positioning and low assembly efficiency.
[0005] With the large-scale planning and construction of desert photovoltaic and wind power, there is an urgent need for a structural design that can actively remove sand and dust from the contacts and enhance the reliability of sealing and positioning, so as to solve the pain points of contact failure and high maintenance costs of existing technologies in dusty environments. Utility Model Content
[0006] In view of this, the present invention provides a moving contact piece and contact box assembly for a sand-resistant auxiliary switch, in order to solve the technical problem in the prior art that the auxiliary switch contacts are prone to poor contact due to the adhesion and accumulation of particulate matter in sandy environments.
[0007] In a first aspect, embodiments of this utility model provide a moving contact for a sand-resistant auxiliary switch, comprising:
[0008] The contact body is arranged in a ring shape and has a through hole inside; the contact body is also provided with a number of rotating protrusions at even intervals;
[0009] The contact includes a first contact and a second contact that are evenly spaced on the contact body; the contact includes an extension arm and a contact block disposed at the end of the extension arm;
[0010] The extension arm extends from the contact body at a preset angle to the end away from the contact body; the contact block is arc-shaped, and the arc protrudes from the bottom end of the contact body.
[0011] Preferably, a first limiting block and a second limiting block are respectively provided on opposite sides of the contact body;
[0012] The first limiting block and the second limiting block are arranged from the side of the contact body at an angle perpendicular to the contact body toward the top of the contact body.
[0013] Preferably, the rotating protrusion is arc-shaped and integrally formed with the contact body.
[0014] Preferably, the two ends of the contact body are respectively provided with riveting posts and riveting holes;
[0015] The rivet post extends from the top of the contact body in a direction perpendicular to the contact body.
[0016] Preferably, the surface of the contact body is provided with a plurality of uniformly distributed slots through a grid-like indentation process.
[0017] Secondly, this utility model embodiment provides a contact box assembly for a wind- and sand-resistant auxiliary switch, the contact box assembly comprising:
[0018] The contact box includes a first boss and a second boss, and a rotation groove for the moving contact piece is provided between the first boss and the second boss.
[0019] The movable contact piece includes a first movable contact piece and a second movable contact piece arranged opposite to each other. The first movable contact piece and the second movable contact piece are riveted together by the riveting post and the riveting hole. The first movable contact piece or the second movable contact piece contacts the first boss through a plurality of the rotating protrusions and is disposed on the top of the first boss, and can rotate through the contact between the rotating protrusions and the first boss.
[0020] A stationary contact piece is placed in a plurality of contact slots provided on the second protrusion. The stationary contact piece includes at least one pair of first stationary contact pieces and second stationary contact pieces provided in the contact slots at both ends of the contact box. When the first stationary contact piece and the second stationary contact piece come into contact with the moving contact piece, the first stationary contact piece and the second stationary contact piece achieve conduction.
[0021] Preferably, the stationary contact includes a first connecting piece for connecting to the moving contact and a second connecting piece for communicating with an external electrical component;
[0022] The second connecting piece has a limiting hole at one end connected to the first connecting piece for fixing the stationary contact piece in the contact piece groove, and the limiting hole is connected to the positioning pin provided in the contact piece groove.
[0023] Preferably, the contact slot is provided with a first connection port and a second connection port;
[0024] The first connecting piece and the second connecting piece are set at a preset angle, and the second connecting piece is installed in the first connecting port or the second connecting port by means of upright or reverse installation.
[0025] Preferably, the first movable contact or the second movable contact is positioned on the first protrusion by the first limiting block and the second limiting block.
[0026] Preferably, both ends of the first and second movable contact pieces after their contacts come into contact are provided with openings, so that the stationary contact piece can make contact with the contacts through the openings, thereby achieving conductivity and scraping off the oxide layer and foreign matter on the stationary contact piece.
[0027] The moving contact and contact box assembly for a wind- and sand-resistant auxiliary switch provided by this utility model has the following beneficial effects:
[0028] In this invention, the arc-shaped contact block protruding downwards on the contact body, together with the opening formed after the first and second moving contact pieces come into contact, can directly scrape away the sand and dust adhering to the surface of the stationary contact piece by sliding the arc surface when the moving contact piece rotates to connect with the stationary contact piece, thus preventing particles from obstructing contact. At the same time, the first and second limiting blocks on both sides of the contact body can limit the moving contact piece within the preset range of the first protrusion of the contact box. Combined with the point contact fulcrum formed by the integrated rotating protrusion and the first protrusion, the stability of the moving contact piece's movement trajectory is ensured. The structure of the extension arm extending from the contact body at a preset angle enhances the structural strength of the connection between the contact block and the contact body. Attached Figure Description
[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of this utility model.
[0030] Figure 1 This is a structural schematic diagram of the contact box assembly;
[0031] Figure 2 This is a structural diagram of the contact box;
[0032] Figure 3 This is a schematic diagram of the assembly of two moving contact pieces;
[0033] Figure 4 This is a schematic diagram of the moving contact.
[0034] Parts and component numbers in the diagram:
[0035] 100-Contact body, 111-Through hole, 112-Rotating protrusion, 121-First contact, 122-Second contact, 123-Extension arm, 124-Contact block, 131-First limiting block, 132-Second limiting block, 133-Riveting post, 134-Riveting hole, 135-Slot;
[0036] 200-Contact box assembly, 210-Contact box, 211-Contact slot, 212-First connection port, 213-Second connection port, 214-Positioning pin, 221-First boss, 222-Second boss, 223-Rotating groove;
[0037] 310 - First moving contact piece, 320 - Second moving contact piece;
[0038] 410-First stationary contact piece, 420-Second stationary contact piece, 431-First connecting piece, 432-Second connecting piece, 433-Limiting hole. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, in this document, relational terms such as "first" and "second" are merely used 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. In the description of this utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Unless otherwise specified, embodiments of the present invention and the various features thereof can be combined with each other, all within the protection scope of the present invention.
[0040] Example 1
[0041] Please see Figure 3 This utility model provides a moving contact for a wind and sand resistant auxiliary switch. The moving contact includes a contact body 100 and a contact disposed on the contact body 100. The contact body 100 is arranged in a ring shape and has a through hole 111 inside. The contact body 100 is also provided with a plurality of rotating protrusions 112 at uniform intervals.
[0042] The contact includes a first contact 121 and a second contact 122 that are evenly spaced on the contact body 100; the contact includes an extension arm 123 and a contact block 124 disposed at the end of the extension arm 123;
[0043] The extension arm 123 extends from the contact body 100 at a preset angle to one end away from the contact body 100; the contact block 124 is arc-shaped, and the arc protrudes from one end of the bottom of the contact body 100.
[0044] Specifically, during the operation of the equipment, the moving contact will slide against the stationary contact. In this process, the contact blocks 124 on every two moving contacts will contact the stationary contact. This contact method ensures that the moving contact can more stably perform its dust-scraping function during opening and closing operations. During opening and closing operations, the moving contact relies on its elastic deformation to apply pressure to the surface of the contact and its surrounding area. This pressure effectively scrapes off sand particles, dust, and other foreign matter adhering to the contact, and also removes the oxide film layer formed on the contact surface due to combustion. In this way, the contacts are always kept clean, thus ensuring good electrical contact performance between the contacts.
[0045] Further, please see Figure 3 The contact body 100 has a first limiting block 131 and a second limiting block 132 on opposite sides. The first limiting block 131 and the second limiting block 132 extend from the side of the contact body 100 toward the top of the contact body 100 at an angle perpendicular to the contact body 100.
[0046] The moving contact piece is equipped with a first limiting block 131 and a second limiting block 132, which are bent and fit together with the boss on the contact box 210. This design not only forms a highly efficient rotary friction pair but also achieves precise positioning during actual use, while ensuring smooth rotation. Through this structural design, the position of the moving contact piece during operation is strictly limited within its normal working range, effectively preventing it from potentially dislodging from the boss in the contact box 210 during operation, further improving the overall reliability and stability of the structure.
[0047] Further, please see Figure 4 The rotating protrusion 112 is arc-shaped and integrally formed with the contact body 100.
[0048] In this embodiment, after the moving contact piece is installed with the protrusion on the contact box 210, when it rotates, it would normally generate surface-to-surface friction. This surface friction has a relatively high coefficient of friction, which can affect the smoothness of rotation. However, through the ingenious design of the arc-shaped rotating protrusion 112, the original surface friction can be effectively transformed into point friction or line friction. This change in friction mode significantly reduces the resistance of the moving contact piece during rotation, making the rotation smoother and more fluid. At the same time, it also significantly increases the service life of the moving contact piece and reduces wear and tear caused by friction.
[0049] Further, please see Figure 3 The contact body 100 is provided with a riveting post 133 and a riveting hole 134 at both ends;
[0050] The rivet post 133 extends from the top of the contact body 100 in a direction perpendicular to the contact body 100.
[0051] When the two movable contact pieces are connected, they are riveted back-to-back. Specifically, a riveting hole 134, which has undergone a stretching process, is provided on one side of the front of the movable contact piece, while a riveting post 133 is provided on the opposite side for mating. During back-to-back installation, the riveting holes 134 and riveting posts 133 formed by the stretching process on the two movable contact pieces are precisely aligned, and then they are riveted together by pressing, making them tightly joined together. This riveting method ensures that the riveted parts have sufficient strength and good stability during use, thereby meeting relevant performance requirements.
[0052] Further, please see Figure 3 The surface of the contact body 100 is provided with a number of evenly distributed slots 135 through a grid-like indentation process.
[0053] Specifically, to ensure the flatness of the moving contact during the riveting process, a grid-like indentation process is applied to its surface. This process involves pressing a grid of indentations into the surface of the moving contact. The optimal arrangement, determined after optimization, is a spacing of 0.5 mm between these indentations and a depth of 0.05 mm for each indentation. This grid-like indentation treatment effectively increases the friction on the moving contact surface. During riveting, the increased surface friction allows the moving contact to better adhere to the relevant components. This significantly reduces potential displacement of the moving contact during riveting, thus effectively ensuring the flatness of the riveting.
[0054] Once the moving contact is riveted, the tightness of its clamping parts can remain highly consistent. This consistency plays a crucial role in ensuring the same clamping force. The same clamping force further ensures the stable and reliable contact resistance between the moving and stationary contacts, which is a critical factor for the normal operation and performance stability of the entire device.
[0055] Example 2
[0056] Please see Figure 1This utility model provides a contact box assembly 200 for a wind and sand resistant auxiliary switch. The contact box assembly 200 includes a contact box 210 and a moving contact and a stationary contact disposed in the contact box 210.
[0057] The contact box 210 includes a first boss 221 and a second boss 222, and a rotating groove 223 for the moving contact piece is provided between the first boss 221 and the second boss 222.
[0058] The movable contact includes a first movable contact 310 and a second movable contact 320 arranged opposite to each other. The first movable contact 310 and the second movable contact 320 are riveted together by the riveting post 133 and the riveting hole 134. The first movable contact 310 or the second movable contact 320 contacts the first boss 221 through a plurality of rotating protrusions 112 and is disposed on the top of the first boss 221, and can rotate through the contact between the rotating protrusions 112 and the first boss 221.
[0059] The stationary contact piece is placed in a plurality of contact slots 211 provided on the second boss 222. The stationary contact piece includes at least one pair of first stationary contact pieces 410 and second stationary contact pieces 420 provided in the contact slots 211 at both ends of the contact box 210. When the first stationary contact piece 410 and the second stationary contact piece 420 come into contact with the moving contact piece, the first stationary contact piece 410 and the second stationary contact piece 420 are connected.
[0060] Specifically, when the auxiliary switch needs to be switched on or off, the moving contact rotates within the rotating groove 223 under the action of an external driving force, with the contact point between the rotating protrusion 112 and the first protrusion 221 as the axis. As the moving contact rotates, its end gradually approaches and contacts the stationary contact. Upon contact, relative friction is generated between the moving and stationary contact. Utilizing this friction, the moving contact can effectively scrape away any oxide layer, accumulated oxide layer, dust, sand, or other foreign matter that may exist on the surface of the stationary contact, ensuring good contact between the two.
[0061] When the moving contact rotates to a position where it is fully in contact with the first stationary contact 410 and the second stationary contact 420, the first stationary contact 410 and the second stationary contact 420 achieve circuit conduction through the moving contact; when the moving contact rotates in the opposite direction and disengages from the stationary contact, the circuit is disconnected. Throughout the process, the first boss 221 and the second boss 222 of the contact box 210 provide stable installation and movement space for the moving and stationary contacts, ensuring that the contact box assembly 200 can still work reliably in harsh environments such as wind and sand.
[0062] Further, please see Figure 1The stationary contact includes a first connecting piece 431 for connecting to the moving contact and a second connecting piece 432 for communicating with an external electrical component;
[0063] The second connecting piece 432 has a limiting hole 433 at one end connected to the first connecting piece 431 for fixing the stationary contact piece in the contact piece groove 211. The limiting hole 433 is connected to the positioning pin 214 provided in the contact piece groove 211.
[0064] Specifically, the stationary contact piece achieves the circuit switching function through the cooperation of the first connecting piece 431 and the moving contact piece. At the same time, the second connecting piece 432 is used to form an effective circuit connection between the stationary contact piece and the external electrical components. The connection between the limiting hole 433 and the positioning pin 214 can accurately limit the position of the stationary contact piece in the contact piece groove 211, preventing the stationary contact piece from being displaced or loosened under the influence of factors such as contact friction of the moving contact piece and vibration of the external environment. This ensures that the contact position between the stationary contact piece and the moving contact piece always remains stable, further improving the overall reliability and stability of the auxiliary switch.
[0065] Further, please see Figure 2 The contact slot 211 is provided with a first connection port 212 and a second connection port 213; the first connecting piece 431 and the second connecting piece 432 are set at a preset angle, and the second connecting piece 432 is disposed in the first connection port 212 or the second connection port 213 by means of upright or reverse installation.
[0066] The contact slot 211, through the preset first connection port 212 and second connection port 213, allows the first connecting piece 431 and the second connecting piece 432 to flexibly adjust their relative positions according to actual installation requirements. The installation method of mounting the stationary contact piece in the forward or reverse direction provides the second connecting piece 432 with the option to choose between the first connection port 212 and the second connection port 213. This flexibility not only broadens the connection and compatibility range of the auxiliary switch with external electrical components, enabling it to adapt to different circuit layouts and installation scenarios, but also optimizes the routing of connection lines within a limited installation space, reduces line crossings and tangles, and lowers the risk of failure due to unreasonable line layout. At the same time, it facilitates the quick assembly of the stationary contact piece by the installer according to the actual site conditions, improving the overall assembly efficiency and ease of use of the auxiliary switch.
[0067] Furthermore, the first movable contact 310 or the second movable contact 320 is positioned on the first boss 221 by the first limiting block 131 and the second limiting block 132.
[0068] The moving contact piece, through the dual limiting action of the first limiting block 131 and the second limiting block 132, can precisely fix the installation position of the first moving contact piece 310 or the second moving contact piece 320 on the first boss 221, avoiding lateral or longitudinal offset during contact and separation with the stationary contact piece. This ensures that the moving contact piece always moves stably along the preset trajectory during operation, thereby guaranteeing the accuracy and effectiveness of the contact between the moving contact piece and the stationary contact piece, reducing contact problems or circuit faults caused by positional deviation of the moving contact piece, and further enhancing the structural stability and electrical performance reliability of the auxiliary switch during operation.
[0069] Further, please see Figure 4 Both ends of the first movable contact 310 and the second movable contact 320 after their contacts come into contact are provided with openings so that the stationary contact can make contact with the contacts through the openings, thereby achieving conduction and scraping off the oxide layer and foreign matter on the stationary contact.
[0070] Specifically, during the contact process between the stationary and moving contacts, the open structure guides the stationary contact to be precisely embedded between the contacts. As the moving contact moves, the contacts and the surface of the stationary contact slide relative to each other. The sliding friction removes any oxide layer, dust, or other foreign matter that may be present on the surface of the stationary contact, preventing problems such as increased resistance or circuit failure caused by poor contact. At the same time, it ensures that the stationary contact and the contacts always maintain good conductive contact, effectively extending the service life of the auxiliary switch and reducing maintenance costs.
[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A moving contact for a wind- and sand-resistant auxiliary switch, characterized in that, include: The contact body (100) is arranged in a ring shape and has a through hole (111) inside; the contact body (100) is also provided with a number of rotating protrusions (112) at uniform intervals. The contact includes a first contact (121) and a second contact (122) evenly spaced on the contact body (100); the contact includes an extension arm (123) and a contact block (124) disposed at the end of the extension arm (123). The extension arm (123) extends from the contact body (100) at a preset angle to the end away from the contact body (100); the contact block (124) is arc-shaped, and the arc protrudes from the bottom end of the contact body (100).
2. The anti-sand auxiliary switch contact according to claim 1, wherein The contact body (100) is provided with a first limiting block (131) and a second limiting block (132) on opposite sides. The first limiting block (131) and the second limiting block (132) are provided to extend from the side of the contact body (100) toward the top of the contact body (100) at an angle perpendicular to the contact body (100).
3. The movable contact for a windblown sand type auxiliary switch according to claim 2, characterized in that The rotating protrusion (112) is arc-shaped and integrally formed with the contact body (100).
4. The anti-sand auxiliary switch contact according to claim 3, wherein The two ends of the contact body (100) are respectively provided with rivet posts (133) and rivet holes (134). The rivet post (133) extends from the top of the contact body (100) in a direction perpendicular to the contact body (100).
5. The movable contact for a sand-resistant auxiliary switch according to claim 1, wherein The surface of the contact body (100) is provided with a number of evenly distributed slots (135) through a grid-like indentation process.
6. A contact box assembly (200) for a windblown sand type auxiliary switch comprising the movable contact as claimed in claim 4; characterized in that, The contact box assembly (200) includes: The contact box (210) includes a first boss (221) and a second boss (222), and a rotating groove (223) for the moving contact piece is provided between the first boss (221) and the second boss (222). The movable contact includes a first movable contact (310) and a second movable contact (320) arranged opposite to each other. The first movable contact (310) and the second movable contact (320) are riveted together by the riveting post (133) and the riveting hole (134). The first movable contact (310) or the second movable contact (320) contacts the first boss (221) through a plurality of the rotating protrusions (112) and is disposed on the top of the first boss (221), and can rotate through the contact between the rotating protrusions (112) and the first boss (221). The stationary contact piece is placed in a plurality of contact slots (211) provided on the second boss (222). The stationary contact piece includes at least one pair of first stationary contact pieces (410) and second stationary contact pieces (420) provided in the contact slots (211) at both ends of the contact box (210). When the first stationary contact piece (410) and the second stationary contact piece (420) come into contact with the moving contact piece, the first stationary contact piece (410) and the second stationary contact piece (420) are connected.
7. The anti-sand contact box assembly (200) for auxiliary switch of claim 6, wherein, The stationary contact includes a first connecting piece (431) for connecting with the moving contact and a second connecting piece (432) for communicating with an external electrical component. The second connecting piece (432) has a limiting hole (433) at one end connected to the first connecting piece (431) for fixing the stationary contact piece in the contact piece groove (211), and the limiting hole (433) is connected to the positioning pin (214) provided in the contact piece groove (211).
8. The anti-sand contact box assembly (200) for auxiliary switch of claim 7, wherein, The contact slot (211) is provided with a first connection port (212) and a second connection port (213); The first connecting piece (431) and the second connecting piece (432) are set at a preset angle, and the second connecting piece (432) is set in the first connecting port (212) or the second connecting port (213) by being installed in the correct direction or in the reverse direction.
9. The anti-sand contact box assembly (200) for auxiliary switch of claim 6, wherein, The first movable contact (310) or the second movable contact (320) is positioned on the first boss (221) by the first limiting block (131) and the second limiting block (132).
10. The anti-sand contact box assembly (200) for auxiliary switch of claim 6, wherein, Both ends of the first movable contact piece (310) and the second movable contact piece (320) after their contacts come into contact are provided with openings so that the stationary contact piece can make contact with the contacts through the openings and achieve conduction and scrape off the oxide layer and foreign matter on the stationary contact piece.