Search

CN-224233471-U - Electromagnetic actuator

CN224233471UCN 224233471 UCN224233471 UCN 224233471UCN-224233471-U

Abstract

The present utility model relates to an electromagnetic actuator. The electromagnetic actuator includes an electromagnetic field generator, a permanent magnet, an armature, a front magnetic pole, a rear magnetic pole, and a push rod, the front magnetic pole and the rear magnetic pole being located at axial both ends of the electromagnetic field generator, respectively, the armature being mounted radially inside the electromagnetic field generator and being axially movable with respect to the electromagnetic field generator, the front magnetic pole and the rear magnetic pole being each capable of being magnetized by the permanent magnet to generate a magnetic attraction force that attracts the armature, the push rod being fixed to the armature and including a first end that extends axially away from the armature and through the front magnetic pole, the electromagnetic actuator further including an elastic member and a holder that is fixedly provided on the push rod and located at a side of the front magnetic pole that is away from the rear magnetic pole in the axial direction, the elastic member being elastically abutted axially between the holder and the front magnetic pole or between the holder and a member that is fixed with respect to the front magnetic pole, whereby an elastic force that keeps the holder away from the front magnetic pole can be exerted. The electromagnetic actuator of the present utility model has an improved structure.

Inventors

  • LIU XIAONA

Assignees

  • 舍弗勒技术股份两合公司

Dates

Publication Date
20260512
Application Date
20250328

Claims (10)

  1. 1. An electromagnetic actuator comprising an electromagnetic field generator, a permanent magnet (40), an armature (50), a front magnetic pole (70 a), a rear magnetic pole (70 b) and a push rod (60), the electromagnetic field generator and the permanent magnet (40) being coaxially arranged, the front magnetic pole (70 a) and the rear magnetic pole (70 b) being located at the axial ends of the electromagnetic field generator, respectively, the armature (50) being mounted radially inside the electromagnetic field generator and being axially movable relative to the electromagnetic field generator between a first extreme position and a second extreme position by being driven by the electromagnetic force of the electromagnetic field generator, the armature (50) abutting the front magnetic pole (70 a) in the first extreme position and the rear magnetic pole (70 b) in the second extreme position, the front magnetic pole (70 a) and the rear magnetic pole (70 b) being respectively capable of being magnetized by the permanent magnet (40) to produce a magnetic attraction force that attracts the armature (50), the push rod (60) being fixed to the armature (50) and comprising a first end extending axially away from the armature (50) and passing through the first end thereof, The electromagnetic actuator further comprises an elastic member (90) and a support (80), wherein the support (80) is fixedly arranged on the push rod (60) and is axially positioned on one side of the front magnetic pole (70 a) away from the rear magnetic pole (70 b), and the elastic member (90) is elastically abutted between the support (80) and the front magnetic pole (70 a) or between the support (80) and a part fixed relative to the front magnetic pole (70 a) along the axial direction, so that elastic force for enabling the support (80) to be away from the front magnetic pole (70 a) can be exerted.
  2. 2. The electromagnetic actuator according to claim 1, wherein when the electromagnetic field generator does not apply an electromagnetic force to the armature (50), the elastic member (90) applies an elastic force to the armature (50) at the second limit position that is smaller than a magnetic attraction force generated by the rear magnetic pole (70 b) to the armature (50) such that the elastic member (90) cannot separate the armature (50) at the second limit position from the rear magnetic pole (70 b).
  3. 3. The electromagnetic actuator according to claim 2, wherein the elastic members (90) are each in a compressed state when the armature (50) is located in any position between the first and second extreme positions.
  4. 4. The electromagnetic actuator according to claim 2, characterized in that the elastic member (90) is formed as a coil spring encircling the radially outer side of the push rod (60).
  5. 5. The electromagnetic actuator according to claim 4, characterized in that the push rod (60) radially constrains the elastic member (90).
  6. 6. Electromagnetic actuator according to claim 4, wherein the seat (80) comprises a first recess (81) towards the front pole (70 a), the axial end of the elastic member (90) towards the seat (80) being fitted into the first recess (81), the first recess (81) radially constraining the elastic member (90), and/or the front pole (70 a) comprises a second recess (71 a) towards the seat (80), the axial end of the elastic member (90) towards the front pole (70 a) being fitted into the second recess (71 a), the second recess (71 a) radially constraining the elastic member (90).
  7. 7. The electromagnetic actuator according to claim 2, characterized in that the push rod (60) passes axially through the seat (80).
  8. 8. The electromagnetic actuator according to claim 2, characterized in that said first end is inserted in said seat (80) and does not protrude beyond said seat (80), the end of said seat (80) facing away from said front pole (70 a) being formed in a configuration suitable for pushing against a driven member.
  9. 9. The electromagnetic actuator according to claim 2, characterized in that the seat (80) is integrally formed with the push rod (60).
  10. 10. The electromagnetic actuator according to any one of claims 1 to 9, wherein the push rod (60) is adapted to engage a ratchet (B) by driving a pawl (a) through the first end.

Description

Electromagnetic actuator Technical Field The utility model relates to the technical field of actuators. In particular, the utility model relates to an electromagnetic actuator. Background An electromagnetic actuator is a component for generating an actuation force. For some applications, the armature of the electromagnetic actuator needs to be held in an extreme position (i.e., in an extended or retracted state) at either end of the interior cavity without energizing, while the switching of the position of the armature is accomplished solely by the electromagnetic force generated upon energizing. This is typically accomplished by generating magnetic attraction forces by magnetizing the front and rear poles with permanent magnets. Such electromagnetic actuators are commonly referred to as bi-stable electromagnetic actuators. For example, with the development of drive-by-wire chassis and electro-mechanical brake (EMB) technology, some current electro-mechanical brake systems employ bistable electromagnetic actuators to achieve a parking lock function. When the vehicle is running normally, the electromagnetic actuator is in a retracted state, and the armature and the rear magnetic pole are kept in abutting contact under the action of magnetic attraction force due to the existence of the permanent magnet. When the armature is propped against the front magnetic pole, the power supply is closed, and the armature and the front magnetic pole are kept propped against each other under the action of the magnetic attraction force due to the existence of the permanent magnet. When the unlocking is needed, reverse current is introduced into the electromagnetic coil, the armature moves towards the rear magnetic pole under the action of reverse electromagnetic force, and after the power supply is turned off, the armature and the rear magnetic pole are kept in abutting connection under the action of magnetic attraction. In park lock applications, an electromagnetic actuator is typically used to push a pawl to engage a ratchet. The pawl may sometimes catch on the top of the ratchet wheel. At this time, since the armature is not at the end position of the stroke, the magnetic attraction force generated by the permanent magnet through the magnetic pole is small enough to push the armature to move in the case of power off. Thus, when the motor adjusts the position of the ratchet, the electromagnetic actuator must be re-energized to move the armature to a position that locks the ratchet. The adjustment mode has higher requirements on control precision and is unfavorable for energy conservation. Disclosure of utility model The object of the present utility model is to provide an improved electromagnetic actuator. The above technical problem is solved by an electromagnetic actuator according to the present utility model. The electromagnetic actuator includes an electromagnetic field generator, a permanent magnet, an armature, a front magnetic pole, a rear magnetic pole, and a push rod coaxially arranged, the electromagnetic field generator and the permanent magnet being located at both axial ends of the electromagnetic field generator, respectively, the armature being mounted on a radially inner side of the electromagnetic field generator and being capable of being driven by an electromagnetic force of the electromagnetic field generator to move axially relative to the electromagnetic field generator between a first limit position and a second limit position, the armature abutting the front magnetic pole at the first limit position and the rear magnetic pole at the second limit position, the front magnetic pole and the rear magnetic pole being capable of being magnetized by the permanent magnet, respectively, to generate a magnetic attraction force that attracts the armature, the push rod being fixed to the armature and including a first end that extends axially away from the armature and passes through the front magnetic pole, the electromagnetic actuator further including an elastic member and a pedestal fixedly provided on the push rod and located on a side of the front magnetic pole that is axially away from the rear magnetic pole, the elastic member being elastically abutted axially between the pedestal and the front magnetic pole or between the pedestal and a member fixed relative to the front magnetic pole, thereby being capable of exerting an elastic force that keeps the pedestal away from the front magnetic pole. The elastic member may provide a pushing force that causes the push rod to protrude outward from the front magnetic pole, and thus the push rod has a tendency to protrude even when no current pushing out of the push rod is applied. When the armature and the push rod are stuck in the middle of the stroke for external reasons, the armature can automatically reach and settle in the first limit position once the external reasons are eliminated, without the need to be energized again to drive the armature. According t