JP2019199943A - Electromagnetic powder brake - Google Patents

Abstract

To inhibit variations of brake force and stably output the brake force.SOLUTION: An electromagnetic powder brake includes: a rotor fixed to a shaft; an annular yoke part which is disposed at an outer periphery of the rotor and houses a coil; and magnetic powder enclosed in a predetermined gap between the yoke part and the rotor. The magnetic powder is bound by magnetic flux generated by energization to the coil to apply brake force to the shaft. The yoke part is formed by combining a magnetic material part formed by a magnetic material with a non-magnetic material part formed by a non-magnetic material in a circumferential direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electromagnetic powder brake.

  Conventionally, this type of electromagnetic powder brake is enclosed in a rotor fixed to a shaft, an annular yoke that is disposed on the outer periphery of the rotor with a predetermined gap therebetween and that accommodates a coil, and a gap between the rotor and the yoke. In addition, a magnetic powder that is applied with a magnetic flux generated by energization of a coil to apply a braking force to a shaft has been proposed (for example, see Patent Document 1). In this electromagnetic powder brake, grooves are provided in the circumferential direction on the inner circumferential surface of the yoke and the outer circumferential surface of the rotor, thereby facilitating uniform distribution of the magnetic powder.

Japanese Patent Application No. 1-90453

  In the electromagnetic powder brake described above, although it is easy to promote a uniform distribution of the magnetic powder, the magnetic flux accompanying the energization of the coil is generated all around the circumference. Therefore, in order to suppress the variation in the braking force, the magnetic powder brake It is necessary to distribute the powder uniformly over the entire circumference. For this reason, it is conceivable to perform a break-in operation in which the electromagnetic powder brake is operated under a predetermined break-in condition before the use of the electromagnetic powder brake is started. However, it is difficult to control the behavior of the magnetic powder in the gap, and it is difficult to set an appropriate break-in condition, and the brake force may vary even if the break-in operation is performed. Also, depending on the object for which the electromagnetic powder brake is used, it may be difficult to perform the running-in operation itself.

  The main object of the present invention is to stably output while suppressing variations in braking force.

  The present invention adopts the following means in order to achieve the main object described above.

  An electromagnetic powder brake according to the present invention is enclosed in a rotor fixed to a shaft, a yoke part disposed around the outer periphery of the rotor and containing a coil, and a predetermined gap between the yoke part and the rotor. An electromagnetic powder brake for applying a braking force to the shaft by coupling the magnetic powder with a magnetic flux generated by energizing the coil, wherein the yoke portion is magnetic in the circumferential direction. The gist is that the magnetic body portion formed of a material is combined with a non-magnetic body portion formed of a non-magnetic material.

  In the electromagnetic powder brake of the present invention, the yoke part is configured by combining a magnetic part and a non-magnetic part in the circumferential direction. For this reason, the range in which the magnetic powder should be uniformly distributed can be narrowed down to the gap between the magnetic body portion and the rotor, so that the entire circumference in the circumferential direction of the yoke portion is magnetic compared to the magnetic body portion. It becomes easy to suppress the dispersion of the powder distribution. Therefore, it is possible to stably output while suppressing variations in brake force.

  In the electromagnetic powder brake of the present invention, the yoke portion is configured such that a part of the inner peripheral portion in the circumferential direction is configured by the magnetic body portion, the remaining portion is configured by the non-magnetic body portion, and the shaft is perpendicular to the vertical direction. It is good also as what is used in the state which becomes the direction which is perpendicular to the direction and the said magnetic body part is located below the said non-magnetic body part. If it carries out like this, since magnetic powder will move the inside of a gap | interval by gravity with the state which is not supplying with electricity to a coil, it will become easy to locate magnetic powder in a gap | interval with a magnetic body part. For this reason, it is possible to stably output the braking force without performing a break-in operation for distributing the magnetic powder in the gap with the magnetic body portion.

  In the electromagnetic powder brake of the present invention, the magnetic powder is enclosed in an amount sufficient to fill a gap between the magnetic body portion and the rotor in the predetermined gap without energizing the coil. It may be a thing. Alternatively, in the electromagnetic powder brake of the present invention, the magnetic powder may be encapsulated so as to cover a region of the magnetic body portion in a state where the coil is not energized. By doing so, it is possible to reliably output the braking force in the region of the magnetic part. In addition, even if the magnetic powder moves in the gap during use of the electromagnetic powder brake, it is possible to prevent the amount of magnetic powder in the gap between the magnetic body portion and the rotor from greatly decreasing. The distribution of braking force can be reliably suppressed.

  In the electromagnetic powder brake of the present invention, the yoke portion may have a ratio of the magnetic body portion of 50% or less with respect to the entire region in the circumferential direction of the inner peripheral portion. By so doing, it is possible to relatively easily realize a configuration that suppresses variations in the distribution of the magnetic powder.

1 is an external perspective view of a vehicle including an electromagnetic powder brake 10. FIG. 1 is a configuration diagram of an electromagnetic powder brake 10. FIG. It is AA sectional drawing of FIG. 1 is an exploded perspective view of an electromagnetic powder brake 10. FIG. 2 is a cross-sectional perspective view showing a main part of the electromagnetic powder brake 10. FIG. 4 is an explanatory diagram showing an example of magnetic flux generated in the electromagnetic powder brake 10. FIG.

   Next, the form for implementing this invention is demonstrated.

  1 is an external perspective view of a vehicle including an electromagnetic powder brake 10, FIG. 2 is a configuration diagram of the electromagnetic powder brake 10, FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, and FIG. FIG. 5 is an exploded perspective view of the electromagnetic powder brake 10, and FIG.

  The vehicle shown in FIG. 1 includes a vehicle body 1, a flip-up back door 2 whose upper end is attached to the rear portion of the vehicle body 1 via left and right hinge mechanisms 4, and can be turned up and down with the hinge mechanism 4 as a fulcrum. The electromagnetic powder brake 10 is provided on one of the left and right hinge mechanisms 4. In the electromagnetic powder brake 10, a shaft 12 that is a rotating shaft is connected to the hinge shaft of the hinge mechanism 4, and magnetic powder is coupled (magnetically attracted) by a magnetic flux generated by energization of the coil via the shaft 12. Thus, a predetermined braking force is applied to the rotation of the hinge mechanism 4. The vehicle shown in FIG. 1 may include an automatic opening / closing device that automatically opens and closes the back door 2.

  As shown in FIGS. 2 to 4, the electromagnetic powder brake 10 includes a rotor 14 that rotates integrally with the shaft 12, a coil bobbin 18 that is fitted to the outer side in the radial direction of the rotor 14, and the coil 16 is wound around. A pair of inner yokes 20 are disposed so as to sandwich the wound coil 16 from both sides in the axial direction, and a cylindrical outer yoke 30 that is disposed on the outer periphery of the coil 16 and the inner yoke 20 and also functions as a case. The electromagnetic powder brake 10 is configured such that the inner yoke 20 and the outer yoke 30 accommodate the coil 16 wound around the coil bobbin 18 therein, and an annular gap (predetermined between the rotor 14 and the inner yoke 20). ), Powder P as magnetic powder is enclosed (see FIG. 3).

  In addition to this, the electromagnetic powder brake 10 includes two bearings 24 that support the shaft 12, two seal members 26 that slide in contact with the outer peripheral surface of the shaft 12 to prevent the powder P from leaking to the outside, and the bearings 24. And two annular holding members 28 having stepped inner diameter portions for holding the sealing member 26. These are restricted in movement in the axial direction by the spacer 32 and the snap ring 34.

  The coil bobbin 18 has an annular portion 18a formed in an annular shape with an inner diameter having a predetermined gap with respect to the outer diameter of the rotor 14, and a diameter (an inner diameter and an outer diameter) from the both edges of the annular portion 18a toward the outer side in the axial direction. The tapered portion 18b is formed in a tapered shape that increases. In the coil bobbin 18, the coil 16 is wound around the outer peripheral surface of the annular portion 18a and each tapered portion 18b, and the inner peripheral surface of each tapered portion 18b functions as a receiving surface for receiving the inner yoke 20, respectively.

  The inner yoke 20 includes, for example, a magnetic body portion 21 (shown in gray) formed of a magnetic material having magnetism such as iron, and a nonmagnetic body portion 22 formed of a nonmagnetic material such as resin or aluminum. These two members are combined. The nonmagnetic body portion 22 is formed with a notch 22a that is partially cut out in a part in the circumferential direction, and the inner yoke 20 is configured by combining the magnetic body portion 21 so as to be fitted into the notch 22a. To do. As described above, the inner yoke 20 has a part in the circumferential direction constituted by the magnetic part 21 and the rest constituted by the non-magnetic part 22. In this embodiment, the inner yoke 20 is magnetic in the circumferential area. The proportion of the body part 21 is about 1/4. The inner yoke 20 (see FIG. 4) in which the magnetic part 21 and the nonmagnetic part 22 are combined includes a tapered part 20a and a tapered part 20a along the inner peripheral surface of the tapered part 18b. And an annular portion 20b extending in an annular shape with a constant diameter (the maximum diameter of the tapered portion 20a) from the edge.

  The outer yoke 30 has a flange portion 31 that extends radially outward from one end side in the axial direction, and a plurality of (for example, four) through holes 31a are formed in the flange portion 31 at equal angular intervals. . The electromagnetic powder brake 10 is attached to the hinge mechanism 4 via an attachment screw or the like inserted through these through holes 31a. As shown in FIGS. 2 and 3, in the electromagnetic powder brake 10, the shaft 12 is oriented perpendicular to the vertical direction, and the magnetic body portion 21 is positioned below the nonmagnetic body portion 22 in the circumferential direction. It is assumed that it is used by being attached to the hinge mechanism 4 in a state of being oriented. Further, when the electromagnetic powder brake 10 is in the state shown in FIG. 2, the powder P is sealed up to the position of the line L in FIG. 2 so as to cover the region of the magnetic part 21. That is, the powder P is sealed so as to sufficiently fill the gap between the rotor 14 and the magnetic body portion 21 in the gap between the rotor 14 and the inner yoke 20. In a non-energized state where the coil 16 is not energized, the powder P remains in the gap between the magnetic body portion 21 and the rotor 14 due to gravity.

  Next, the operation of the electromagnetic powder brake 10 thus configured will be described. The control device for the back door 2 applies a predetermined braking force to the rotation of the hinge mechanism 4 by energizing the coil 16 of the electromagnetic powder brake 10. For example, the control device continues to apply a weak braking force by energizing a relatively weak current when the opening / closing operation of the back door 2 is performed, or is relatively strong when a predetermined holding condition is satisfied. The position of the back door 2 is maintained by applying a strong braking force by energizing the current. The predetermined holding condition is established when, for example, the user gives an instruction to hold the back door 2 via a switch (not shown), or during opening / closing of the back door 2 via an obstacle detection sensor (not shown). For example, it may be established when an obstacle is detected. Further, when the back door 2 is held, if the user gives an instruction to release the back door 2 via a switch or the like (not shown), the holding can be released.

  Here, FIG. 6 is an explanatory view showing an example of the magnetic flux generated in the electromagnetic powder brake 10. 6A shows an image of magnetic flux on the upper side of the electromagnetic powder brake 10 by a dotted line, and FIG. 6B shows an image of magnetic flux on the lower side of the electromagnetic powder brake 10 by a dotted line. As described above, the inner yoke 20 is used in such a direction that the non-magnetic body portion 22 is positioned on the upper side and the magnetic body portion 21 is positioned on the lower side, so that the magnetic resistance is higher on the upper side than on the lower side. . For this reason, the magnetic flux generated on the upper side is smaller than the magnetic flux generated on the lower side, and the magnetic flux contributing to the braking force is almost the magnetic flux generated at the location where the lower magnetic body portion 21 is disposed. Further, part of the powder P may be wound up by the rotation of the rotor 14 during operation of the electromagnetic powder brake 10, but in this embodiment, since the magnetic flux on the upper side is small, the powder P hardly stays on the upper side. It becomes easy to return to the lower side by gravity. Further, in the case where the entire circumference of the inner yoke 20 is configured by the magnetic body portion, the powder P may move upward due to magnetic attraction by the magnetic flux on the upper side, but in this embodiment where the magnetic flux on the upper side is small, Such movement will hardly occur. Accordingly, even during operation of the electromagnetic powder brake 10, most of the powder P is located on the lower side. Of course, since the amount of powder P covering the magnetic body portion 21 is enclosed, even if a part of the powder P moves, the powder P filling the gap between the magnetic body portion 21 and the rotor 14 is prevented from being insufficient. can do.

  Accordingly, even during operation of the electromagnetic powder brake 10, the gap between the magnetic body portion 21 and the rotor 14 can be filled with the powder P, and the distribution of the powder P in the gap can be made uniform. The brake force can be stably output while suppressing variations in magnetic flux generated on the side. For this reason, the braking force can be stabilized without requiring a break-in operation of the electromagnetic powder brake 10. In the configuration of the present embodiment, the magnetic force in the non-magnetic body portion 22 is reduced, so that the braking force for the physique of the electromagnetic powder brake 10 is smaller than that in which the entire circumference of the inner yoke 20 is configured by the magnetic body portion. It becomes. However, even if the entire circumference of the inner yoke 20 is formed of a magnetic body portion, it is difficult to control the behavior of the powder P and distribute it uniformly over the entire circumference, and the brake force may vary. For this reason, there is a case where the physique has to be enlarged so that a sufficient braking force can be secured even at the lower limit of the range of variation in the braking force. In this embodiment, even if the braking force is reduced, it can be output stably. Therefore, the necessary range of the magnetic body portion 21 is appropriately determined from the required braking force and designed to have an appropriate physique. Is possible. Further, the amount of the powder P is determined by taking into consideration the balance between the rotational resistance in a non-energized state where the coil 16 is not energized and the necessary braking force generated by the coupling of the energized state, and the like. It can be set to an amount more than filling the gap. Here, in the case where the entire circumference of the inner yoke 20 is constituted by the magnetic body portion, in order to uniformly distribute the powder P over the entire circumference, the electromagnetic powder brake 10 is usually required to be conditioned. As such a running-in operation, for example, a continuous operation of about several minutes is performed in a state where a predetermined current is supplied to the coil 16, and therefore, it is difficult to perform the running-in operation when the electromagnetic powder brake 10 is used for the back door 2. . In the present embodiment, since the braking force can be stabilized without performing the running-in operation, there is an advantage that the running-in operation is unnecessary. Furthermore, the non-magnetic part 22 such as resin is included in the inner yoke 20, so that the electromagnetic powder brake 10 can be reduced in weight as compared with the case where the entire circumference is constituted by the magnetic part. In addition, although the vertical direction of the electromagnetic powder brake 10 is regulated, this can be handled relatively easily by an operator confirming the direction when the electromagnetic powder brake 10 is attached.

  In the electromagnetic powder brake 10 described above, the inner yoke 20 is configured by combining the magnetic body portion 21 and the non-magnetic body portion 22 in the circumferential direction. Therefore, the range in which the powder P should be uniformly distributed is defined between the magnetic body portion 21 and the rotor. 14 can be narrowed down. For this reason, it is easy to suppress the variation in the distribution of the powder P as compared with the case where the entire circumference of the inner yoke 20 is formed of a magnetic body portion, and it is possible to stably output while suppressing the variation in the braking force.

  Further, since the electromagnetic powder brake 10 is used in a direction in which the magnetic body portion 21 is positioned below the nonmagnetic body portion 22, the gap between the magnetic body portion 21 and the rotor 14 is caused by gravity of the powder P in a non-energized state. The break-in operation can be made unnecessary.

  Further, since the powder P is sealed to such an extent that the gap between the magnetic body portion 21 and the rotor 14 is filled in the non-energized state, the powder P is uniformly distributed in the gap, and the powder P is used during use of the electromagnetic powder brake 10. The shortage of the amount of powder P in the gap can be suppressed. Therefore, the variation in brake force can be more reliably suppressed.

  Further, in the inner yoke 20, since the ratio of the area occupied by the magnetic body portion 21 to the area of the entire circumference in the circumferential direction is about 1/4, the balance between the rotational resistance in the non-energized state and the braking force in the energized state is balanced. It is easy to take, and the structure which suppresses the dispersion | distribution of the distribution of the powder P is easily realizable.

  In the embodiment described above, the ratio of the area occupied by the magnetic part 21 is about 1/4. However, the ratio is not limited to this, and it is about 50% or less such as about 1/2 or less or about 1/3 or less. Also good. If it is 50% or less, the structure which suppresses the dispersion | distribution of the distribution of the powder P is easily realizable. Further, if it exceeds 50%, the amount of powder P to be encapsulated in order to distribute uniformly increases, and there is a concern such as an increase in rotational resistance in a non-energized state. Further, there is a concern about reliability such as powder P entering the shaft 12 and lowering durability. Therefore, the upper limit is preferably 50% or less.

  In the embodiment, the amount of the powder P that fills the gap between the magnetic body portion 21 and the rotor 14 in the non-energized state is enclosed. However, the present invention is not limited to this, and the magnetic body portion 21 and the rotor are not energized. The amount of powder P may be larger than the degree of filling the gap with 14, for example, the amount of powder P that fills the gap on the lower half side. Or it is good also as what encloses the powder P of a little little quantity rather than filling the clearance gap between the magnetic body part 21 and the rotor 14. FIG.

  In the embodiment, the inner yoke 20 is used in a state where a part of the inner yoke 20 is constituted by the magnetic part 21 and the remaining part is constituted by the non-magnetic part 22, and the magnetic part 21 is positioned below the non-magnetic part 22. It was supposed to be, but it is not limited to this. For example, the inner yoke 20 may be configured by combining a plurality of magnetic bodies and a plurality of nonmagnetic bodies in the circumferential direction. In such a case, the total ratio of the magnetic body region may be 50% or less with respect to the entire circumferential region in the circumferential direction. Further, for example, the magnetic body portion occupies more than 70% of the region in the lower half in the circumferential direction, and the region occupied by the magnetic body portion in the lower half region should be larger than the region occupied by the non-magnetic portion. That's fine. In such a case, the non-magnetic part may be a non-magnetic part such as a non-magnetic part positioned on the vertical line in the lower half area.

  In the embodiment, the nonmagnetic body portion 22 and the coil bobbin 18 of the inner yoke 20 are configured as separate parts. However, the present invention is not limited to this, and the nonmagnetic body portion 22 and the coil bobbin 18 are integrally formed using a resin or the like. Thus, it may be configured as one component.

  In the embodiment, among the yoke parts constituted by the inner yoke 20 and the outer yoke 30, the inner yoke 20 located on the inner peripheral part is configured by combining the magnetic part 21 and the non-magnetic part 22. However, the outer yoke 30 located on the outer peripheral portion may be configured by combining a magnetic part and a non-magnetic part. Moreover, the yoke part should just be a cyclic | annular thing arrange | positioned in the outer periphery of the rotor 14, and can accommodate the coil 16, and is not restricted to what is comprised by two components, an inner yoke and an outer yoke.

  In the embodiment, the electromagnetic powder brake 10 is used for the back door 2 of the vehicle. However, the present invention is not limited to this, and may be used for other doors of the vehicle such as a swing door and a slide door of the vehicle. Moreover, it is not restricted to what is used for the door of a vehicle, It is good also as what uses the electromagnetic powder brake 10 for another use.

  The correspondence between the main elements of the present embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the present embodiment, the shaft corresponds to “shaft 12”, the rotor 14 corresponds to “rotor”, the coil 16 corresponds to “coil”, the inner yoke 20 and the outer yoke 30 correspond to “yoke part”, The powder P corresponds to “magnetic powder”, the magnetic part 21 of the inner yoke 20 corresponds to “magnetic part”, and the non-magnetic part 22 corresponds to “non-magnetic part”. Further, the inner yoke 20 corresponds to the “inner peripheral portion of the yoke portion”.

  Note that the correspondence between the main elements of the present embodiment and the main elements of the invention described in the section for solving the problem is the invention described in the section of the means for solving the problem in the present embodiment. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be made based on the description of the column, and this embodiment is the invention described in the column of means for solving the problem. It is only a specific example of.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  The present invention is applicable to the electromagnetic powder brake manufacturing industry.

  DESCRIPTION OF SYMBOLS 1 Car body, 2 Back door, 4 Hinge mechanism, 10 Electromagnetic powder brake, 12 Shaft, 14 Rotor, 16 Coil, 18 Coil bobbin, 18a Annular part, 18b Tapered part, 20 Inner yoke, 20a Tapered part, 20b Annular part, 21 Magnetic body part, 22 Non-magnetic body part, 22a Notch, 24 Bearing, 26 Seal member, 28 Holding member, 30 Outer yoke, 31 Flange part, 31a Through hole, 32 Spacer, 34 Snap ring, L line, P powder.

Claims (5)

A rotor fixed to the shaft, an annular yoke portion arranged around the rotor and containing a coil, and a magnetic powder sealed in a predetermined gap between the yoke portion and the rotor. An electromagnetic powder brake for applying a braking force to the shaft by combining the magnetic powder with a magnetic flux generated by energizing the coil,
The yoke part is configured by combining, in the circumferential direction, a magnetic body part made of a magnetic material and a non-magnetic body part made of a non-magnetic material. The electromagnetic powder brake according to claim 1,
The yoke portion is configured such that a part of the inner peripheral portion in the circumferential direction is configured by the magnetic body portion and the remaining portion is configured by the non-magnetic body portion,
An electromagnetic powder brake that is used in a state in which the shaft is in a direction perpendicular to the vertical direction and the magnetic body portion is positioned below the non-magnetic body portion. The electromagnetic powder brake according to claim 2,
The electromagnetic powder brake includes an amount of the magnetic powder that fills a gap between the magnetic body portion and the rotor in the predetermined gap without energizing the coil. The electromagnetic powder brake according to claim 2,
The magnetic powder brake is encapsulated so as to cover a region of the magnetic body portion in a state where the magnetic powder is not energized. The electromagnetic powder brake according to any one of claims 1 to 4,
The electromagnetic powder brake, wherein the yoke portion has a ratio of the magnetic body portion to 50% or less with respect to the entire region in the circumferential direction of the inner peripheral portion.