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EP-4742282-A1 - ELECTROMAGNETIC LINEAR ACTUATOR

EP4742282A1EP 4742282 A1EP4742282 A1EP 4742282A1EP-4742282-A1

Abstract

The invention relates to an electromagnetic linear actuator (10) for moving a rod (300) along an axial direction (A) relative to a support structure (600). The electromagnetic actuator comprises an exciting coil (400) wound around a circumferential direction (C) perpendicular to the axial direction (A); a fixed core (500) located at a first axial end of the coil (400) and fixed to the support structure (600); a and rod-moving arrangement comprising a rod-moving core (100) arranged at a second axial end of the coil (400) and for attaching to the rod (300). The rod-moving core (100) is moving between an open position when the coil (400) is not energized and a closed position when the coil (400) is energized. The open position and the closed position are spaced apart in the axial direction (A) by a rod-moving distance (d_rod). The electromagnetic actuator comprises further a shock-absorbing arrangement comprising a shock-absorbing core (200) disposed between the fixed core (500) and the rod-moving core (100). The shock-absorbing core (200) is moving between a stop position, in which the shock-absorbing core (200) is retained by a retaining force for blocking the rod-moving core (100) to move in the closed position when the coil (400) is not energized and a release position in which the shock-absorbing core (200) enables the rod-moving core (100) to move to the closed position when the coil (400) is energized, the stop position and the release position being spaced apart in the axial direction (A) by a shock-absorbing distance (d_shock) The shock-absorbing distance (d_shock) is less than or equal to the rod-moving distance (d_rod).

Inventors

  • Fontes, Hugo
  • KROEKER, MATTHIAS
  • DUARTE SILVA, Antonio Perdigao
  • MOREIRA, Vitor

Assignees

  • TE Connectivity Solutions GmbH
  • Tyco Electronics Componentes Electromecânicos Lda

Dates

Publication Date
20260513
Application Date
20241108

Claims (15)

  1. Electromagnetic linear actuator (10) for moving a rod (300) along an axial direction (A) relative to a support structure (600), the electromagnetic actuator comprising: an exciting coil (400) wound around a circumferential direction (C) perpendicular to the axial direction (A); a fixed core (500) located at a first axial end of the coil (400) and fixed to the support structure (600); a rod-moving arrangement comprising a rod-moving core (100) arranged at a second axial end of the coil (400) and for attaching to the rod (300), the rod-moving core (100) moving between an open position when the coil (400) is not energized and a closed position when the coil (400) is energized, the open position and the closed position being spaced apart in the axial direction (A) by a rod-moving distance (d_rod); a shock-absorbing arrangement comprising a shock-absorbing core (200) disposed between the fixed core (500) and the rod-moving core (100), the shock-absorbing core (200) moving between a stop position, in which the shock-absorbing core (200) is retained by a retaining force and a release position in which the shock-absorbing core (200) enables the rod-moving core (100) to move to the closed position when the coil (400) is energized, the stop position and the release position being spaced apart in the axial direction (A) by a shock-absorbing distance (d_shock); and wherein the shock-absorbing distance (d_shock) is less than or equal to the rod-moving distance (d_rod).
  2. Electromagnetic linear actuator (10) according to claim 1, wherein, when the rod-moving core (100) is in the open position, the rod-moving core (100) is spaced apart from the shock-absorbing core (200) and the shock-absorbing core (200) is spaced apart from the fixed core (500) and the retaining force is for blocking the rod-moving core (100) to move in the closed position when the coil (400) is not energized.
  3. Electromagnetic linear actuator (10) according to any of the preceding claims, when the rod-moving core (100) is in the closed position, the rod-moving core (100) is touching the shock-absorbing core (200) and the shock-absorbing core (200) is touching the fixed core (500).
  4. Electromagnetic linear actuator (10) according to any of the preceding claims, wherein the shock-absorbing core (200) and the fixed core (500) comprise a flat surface (214, 514) extending perpendicular to the axial direction (A) for contacting each other when the shock-absorbing core (200) is in the release position, optionally wherein the flat surface (214, 514) is arranged in a central region within the coil (400).
  5. Electromagnetic linear actuator (10") according to any of the preceding claims, each of the shock-absorbing core (200) and the rod-moving core (100) comprise a conical surface (216, 116) that chamfers in an axial direction (A) for contacting each other when the rod-moving core (100) is in the closed position.
  6. Electromagnetic linear actuator (10) according to any of the preceding claims, wherein the rod-moving arrangement further comprises a holding spring (110) for urging the rod-moving core (100) with a holding force in the open position when the coil (400) is not energized, optionally wherein the holding spring (110) is attached to the rod-moving core (100) and the fixed core (500).
  7. Electromagnetic linear actuator (10') according to any of the preceding claims, wherein the shock-absorbing arrangement further comprises a force-mediating element (210, 210') for urging the shock-absorbing core (200) with a force in the direction of the rod-moving core.
  8. Electromagnetic linear actuator (10') according to claim 7, wherein the force mediating element comprises at least one of a force-mediating spring (210), which is preferably attached to the shock-absorbing core (200) and the fixed core (500), and a permanent magnet (210'), which is preferably disposed between the rod-moving core (100) and the shock-absorbing core (200), the shock-absorbing core (200) for taking over momentum in case of shocks.
  9. Electromagnetic linear actuator (10') according to claims 6 to 8, wherein the force-mediating spring (210) has a different spring rate than the holding spring (110), optionally wherein the force-mediating spring (210) is surrounding in a circumferential direction (C) the holding spring (110).
  10. Electromagnetic linear actuator (10, 10') according to any of the preceding claims, wherein the shock-absorbing core (200) comprises a resting core-projection (220) extending in a radial direction (R) perpendicular to the axial direction (A), the resting core-projection (220) limiting the movement of the shock-absorbing core (200) in the stop position in the direction of the stop position, optionally wherein the force-mediating spring (210) of claim 8 is attached to the resting core-projection (220) of the shock-absorbing core (200) and the fixed core (500).
  11. Electromagnetic linear actuator (10) according to any of the preceding claims, wherein the support structure (600) comprises a resting support-projection (620) extending in a radial direction (R) perpendicular to the axial direction (A), the resting support-projection (620) limiting the movement of the shock-absorbing core (200) in the stop position in the direction of the stop position so that the shock-absorbing distance (d_shock) is less than the rod-moving distance (d_rod).
  12. Electromagnetic linear actuator (10) according to any of the preceding claims, wherein the shock-absorbing core (200) is spaced apart from the rod (300), optionally wherein the shock-absorbing core (200) comprises a through hole (212) and the rod (300) is guided in the through hole (212).
  13. Electromagnetic linear actuator (10) according to any of the preceding claims, wherein the support structure (600) comprises a core-guide portion (610) for guiding the movement of the rod-moving core (100) along the axial direction (A), optionally wherein the core-guide portion (610) comprises a hole (612) and the rod-moving core (100) is guided in the through hole (612), optionally wherein the core-guide portion (610) of the support structure (600) comprises a ferromagnetic material and/or wherein the fixed core (500) comprises a rod-guide portion (512) for guiding the movement of the rod (300) along the axial direction (A), optionally wherein the fixed core (500) comprises a through hole (512) and the rod (300) is guided in the through hole (512).
  14. Electromagnetic linear actuator (10) according to any of the preceding claims further comprising the rod (300) attached to the rod-moving core (100), wherein the rod (300) comprises a limiting projection (310) extending in a radial direction (R) perpendicular to the axial direction (A), the limiting projection (310) limiting the movement of the rod (300) in the open position in the direction of the open position.
  15. Switch for switching an electric circuitry, the switch comprising an electromagnetic linear actuator (10) according to any of the preceding claims.

Description

The invention relates to an electromagnetic linear actuator. An electromagnetic actuator 1000, as for example shown in Fig. 17, is a device that converts electrical energy into mechanical motion through the use of electromagnetic principles. A linear actuators creates straight-line motion, here along an axial direction A. Here, a rod 1300, which is a long, slender bar, designed to withstand forces and transmit loads in the mechanical system, is arranged within the electromagnetic actuator 1000 and is moved by the electromagnetic actuator along an axial direction A. To move the rod 1300, the electromagnetic actuator comprises an electromagnet, which is created by passing an electric current through a coil 1400 of wire. The coil 1400 is wound around a circumferential direction C thereby surrounding for example at least a part of the rod 1300. The coil 1300 generates a magnetic flux B. A magnetic flux density, often represented by a vector field with vectors denoted by the symbol B, is a measure of the strength and direction of the magnetic field at a specific point. The generated magnetic flux B can interact with ferromagnetic materials (like iron or steel), creating a force that can move these materials. A magnetic flux B attracts or repels the moveable core 1100, depending on the actuator's design. This movement can be harnessed to perform mechanical work, namely moving the rod 1300. Thus, the electromagnetic actuator can move for example contacts of electrical switches. The electromagnetic actuator can also used for the purpose such as moving a valve, pressing a button, or driving a linear mechanism. In general, electromagnetic linear actuator facilitate compared to other actuating devices high precision and control, fast response time, high efficiency in converting electrical energy to mechanical energy, smooth and continuous motion, low maintenance, quiet operation and high force density. Further requirements may be need to be fulfilled for an electromagnetic actuator depending on the application. For example, a requirement may relate to a rod-moving distance, which is, as shown in Fig. 17, the distance between an open position when the coil is not energized and a closed position when the coil is energized. This rod-moving distance is for example predefined. Thus, it can be ensured that contacts of a switch are sufficiently spaced apart in the open position. Further, a shock resistance to hold the open position, i.e. when the coil is not energized, in view of external shocks may be defined. As used herein, a mechanical shock is a sudden and often extreme force or impact that is applied to the electromagnetic actuator. It typically involves a rapid change in velocity, i.e. an acceleration, during for a very short period of time, causing stress and potential damage to the components of the system, e.g. by moving the actuator from an open position to a closed position. For example, switches such as high voltage contactors have to withstand up to 90 g mechanical shocks. In other words, the acceleration in case of shock ashock = 90 g. To increase the shock resistance, a retaining force for retaining the actuator in the open position can be increased, for example by increasing a spring rate to urge the actuator in the open position. For example, an actuator with mass ma experiences a shock force Fshock = ma* ashock. Further, the actuator may be limited in view of weight and installation space requirements. The object of the invention is to provide a solution for an actuator that is improved in parameters of the rod-moving distance, the resistance, the weight, and installation space. At the same time, modifications shall not significantly influence properties such as high precision and control, fast response time, high efficiency in converting electrical energy to mechanical energy, smooth and continuous motion, low maintenance, quiet operation and high force density. This object is solved by the independent claim. Advantageous embodiments are solved by the dependent claims. According to a general aspect, the actuator, as described above with Fig. 17, additionally comprises a shock-absorbing core disposed between a fixed core and a rod-moving core in a coil. The shock-absorbing core and the rod-moving core for forming at least in part an armature. The shock-absorbing core can move between a stop position and a release position, which are spaced apart in the axial direction by a shock-absorbing distance. The shock-absorbing core experiences a retaining force that retains the shock-absorbing core. This retaining force is for blocking the rod-moving core to move in the closed position when the coil is not energized or for holding the shock-absorbing core with a predetermined force together. This arrangement with an armature comprising two separate cores facilitates to increase the shock resistance. For example, the shock-absorbing core can act as a stopper for the rod-moving core. The retaining force is then for b