JP4070226B2 - Electromagnetic linear actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic linear actuator.
[0002]
[Prior art]
The cylindrical case in the linear actuator that extracts the axial force by electromagnetic induction and the cap that closes the opening of the linear actuator can be integrally coupled by tightening the outward flanges formed on the outer periphery of each other with bolts. It is common.
[0003]
[Problems to be solved by the invention]
However, according to this conventional structure, since it is bolted at a position projecting radially outward from the outer contour of the case, the number of parts increases because bolts are required, as well as an increase in the size of the device configuration. The assembly man-hours tended to increase because the bolts had to be tightened.
[0004]
The present invention is for solving such problems imposed on the prior art, and the object of the present invention is to reduce the number of parts and the number of assembly steps without increasing the size. Another object is to provide an electromagnetic linear actuator.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, the stator 5, the armature 9 that can move in the axial direction with respect to the stator, and the rod 7 that is integrated with the armature to extract the axial force applied to the armature. In the cylindrical case 3, the stator includes a plurality of solenoid pieces 4, and the plurality of solenoid pieces are pressed in the axial direction so that the plurality of solenoid pieces are placed in the case. A hollow outer screw nut 19 is provided for holding inside, a female screw part 13 is formed on the inner peripheral surface of the case, and a cap 10 for sealing the case is provided at the opening of the case, The cap has a male threaded portion 32, an enlarged diameter portion 34 that contacts the open end of the case, and a lock through which the rod is inserted. Insertion holes 10a and are formed, and the hollow outer threaded nut and said cap, in a state spaced each other in the axial direction, and assumed to be screwed together in successive screw groove of the female screw portion of the case.
[0006]
According to this, it is not necessary to project the cap radially outward from the outer contour of the case, and the bolt becomes useless, and the tightening process becomes useless. In addition, a special part for holding the stator in the case becomes unnecessary.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to specific embodiments shown in the accompanying drawings.
[0008]
FIG. 1 shows an electromagnetic linear actuator (hereinafter referred to as an actuator) constructed according to the present invention. The actuator 1 has a bottomed cylindrical shape, a case 3 provided with a joint 2 made of a ball stud on the top surface thereof, and a number of solenoids having an annular shape laminated on the inner peripheral surface of the case 3 in the axial direction. A stator 5 composed of a piece 4, a rod 7 that extends on the central axis of the case 3 and that has a joint 6 composed of a ball stud at one end protruding from the opening of the case 3, and is laminated on the outer periphery of the rod 7. The armature 9 is composed of a large number of pole pieces 8.
[0009]
The opening of the case 3 is sealed with a cap 10 in which a rod 7 is inserted into a rod insertion hole 10a provided at the center thereof. The cap 10 is airtightly fitted with the boss portion 12 to the opening end of the case 3 with an O-ring 11 interposed therebetween, and is screwed into a female screw portion 13 formed inside the opening. In addition, the seal member 14 is hermetically sealed between the inner periphery of the rod insertion hole 10 a and the outer periphery of the rod 7.
[0010]
Here, the case 3 is described as being opened downward for convenience, but it goes without saying that the direction is not restricted in practice.
[0011]
As shown in FIG. 2, the solenoid piece 4 constituting the stator 5 includes a thin bobbin 16 made of a magnetic soft iron material provided with a recess 15 on the inner peripheral side, and an air-core coil 17 formed by winding a conducting wire. ing. The stator 5 is screwed into a female screw 13 formed on the inner peripheral surface of the opening end side of the case 3 with both end portions in the axial direction where a large number of solenoid pieces 4 are stacked sandwiched between end collars 18a and 18b. The hollow outer screw nut 19 is held in the case 3 while being pressed in the axial direction. Each set of three air-core coils 17 in the stacking order is connected to the power supply lead S after being delta-connected.
[0012]
As shown in FIG. 2, the armature 9 is composed of an annular permanent magnet 20, a pair of annular yokes 21 made of a magnetic soft iron material sandwiching the magnets from above and below, and a stainless steel material sandwiched between the outer peripheral sides of the pair of annular yokes 21. A large number of pole pieces 8 composed of a magnetic shield ring 22 are stacked on the rod 7, both ends thereof are sandwiched between end collars 23 a and 23 b, and a nut 24 screwed to the top end side of the rod 7 is tightened. The rod 7 is integrally connected.
[0013]
The pole pieces 8 adjacent to each other are arranged such that the S poles and the N poles are alternately inverted.
[0014]
The armature 9 is slidably supported by oil-impregnated slide bushes 25 a and 25 b made of sintered alloy fitted to end collars 18 a and 18 b that hold both ends of the stator 5, and is movable in the axial direction together with the rod 7. . Here, in order to reduce frictional resistance against the slide bushes 25a and 25b and to prevent wear, the outer peripheral surface of the armature 1 is polished and a hard coating 26 such as hard chrome is formed.
[0015]
As described above, the rod 7 is linearly driven by the axial force generated in the armature 9 by sequentially exciting the solenoid pieces 4 in synchronism with the output of the pole piece position detecting means 27 using the Hall element. The linear motor type actuator 1 is configured. Since the principle of the linear motor is already known, further explanation is omitted here.
[0016]
The case 3 encloses the armature 9 together with the rod 7, and vacant spaces 28 a and 28 b are formed between the top surface of the case 3 and the inner surface of the cap 10, and both axial end surfaces of the armature 9. Yes. Since the volume of both the vacant chambers 28a and 28b changes with the movement of the armature 9, in order to balance the internal pressure of both the vacant chambers 28a and 28b, an air passage 29 that communicates between the vacant chambers 28a and 28b is provided. It is provided at the center of the rod 7.
[0017]
As shown in an enlarged view in FIG. 3, a smooth inner peripheral portion 31 and a female screw portion 13 are sequentially formed on the inner peripheral surface of the case 3 on the opening end side inward from the opening end. The boss portion 12 of the cap 10 is formed with a male screw portion 32 that is screwed to the female screw portion 13 and a smooth outer peripheral portion 33 that is fitted to the smooth inner peripheral portion 31 of the case 3. An enlarged diameter portion 34 is formed in contact with the. A hollow outer screw nut 19 is screwed to the innermost axial position of the female screw portion 13.
[0018]
When the male threaded portion 32 of the cap 10 is tightened into the female threaded portion 13 of the case 3 using a special tool such as a crab spanner or a hook wrench, the case 3 is formed by fitting the smooth inner peripheral portion 31 and the smooth outer peripheral portion 33 together. And the cap 10 are coupled with high concentric accuracy. Thereby, it is possible to prevent the seal member 14 interposed between the rod 7 and the rod insertion hole 10a from being hit by one piece.
[0019]
Embodiment FIG. 4 shows a suspension device to which the device of the present invention is applied. In the present embodiment, the actuator 1 of the present invention is used as a stabilizer link that connects each end of the stabilizer rod R to the left and right suspension arms A.
[0020]
As is well known, the stabilizer rod R has substantially no effect when the left and right wheels W move up and down in the same phase, but when the left and right wheels W move up and down in the opposite phase, the torsional rigidity of the wheels W A deterrent is added to the vertical movement, and the higher the rigidity, the less the change in posture during turning, and the lower the rigidity, the higher the riding comfort on the flat road. That is, it can be said that the rigidity of the stabilizer rod R is determined by a compromise between the turning stability and the ride quality on a flat road.
[0021]
For example, when one wheel W rides on a protrusion while traveling on a flat road, a force that prevents the wheel W from being lifted by the action of the stabilizer rod R works for a normal vehicle. If provided on the side of one wheel W, in this case, by shortening the actuator 1 so as to absorb the force of the stabilizer rod R, the wheel W moves up smoothly and the vibration is not transmitted to the vehicle body. Conversely, when one wheel W falls into the recess, the force of the stabilizer rod R can be absorbed by extending the actuator 1. That is, the apparent spring force of the stabilizer rod R can be continuously changed by providing the actuator 1 on at least one of the left and right ends of the stabilizer rod R and expanding or contracting it appropriately. That is, the device of the present invention can further improve the balance between turning stability and riding comfort on a flat road.
[0022]
【The invention's effect】
As described above, according to the present invention, the configuration of the case of the electromagnetic linear actuator is screwed into the female screw portion and the smooth inner peripheral portion and the female screw portion that are formed in the inner peripheral surface in order from the opening end to the inside. And a cap having a smooth outer peripheral portion fitted to the smooth inner peripheral portion, a diameter increasing portion contacting the opening end, and a rod insertion hole, and the outer peripheral surface of the cap as the inner peripheral surface of the case Since the cap is not required to protrude radially outward from the outer contour of the case, bolts are unnecessary, and the tightening process is also unnecessary. A great effect can be achieved in reducing the cost. Furthermore, according to the invention of claim 2, since the hollow external screw nut that presses the stator formed by laminating a large number of solenoid pieces in the axial direction and holds the stator in the case is screwed to the female screw portion. Special parts for holding the stator in the case are not required, which is effective in reducing manufacturing costs.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an electromagnetic linear actuator according to the present invention. FIG. 2 is an enlarged sectional view of a solenoid piece and a pole piece. FIG. 3 is an enlarged sectional view of a main part of the present invention. Front view of the main part of the suspension system [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Actuator 3 Case 5 Stator 7 Rod 9 Armature 10 Cap 10a Rod insertion hole 13 Female thread part 19 Hollow external thread nut 31 Smooth inner peripheral part 32 Male thread part 33 Smooth outer peripheral part 34 Wide diameter part

Claims (1)

An electromagnetic linear actuator comprising a stator, an armature that is axially movable with respect to the stator, and a rod that is integral with the armature for taking out an axial force applied to the armature, in a cylindrical case. There,
The stator includes a number of solenoid pieces,
A hollow external screw nut for pressing the multiple solenoid pieces in the axial direction to hold the multiple solenoid pieces in the case is provided,
While an internal thread is formed on the inner peripheral surface of the case,
A cap for sealing the case is provided at the opening of the case,
The cap is formed with a male screw portion, a diameter-expanded portion that contacts the opening end of the case, and an insertion hole through which the rod is inserted.
The electromagnetic linear actuator, wherein the hollow outer screw nut and the cap are screwed together in a continuous thread groove of the female screw portion of the case in a state of being separated from each other in the axial direction .

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