JP4220275B2 - Electromagnetic brake - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic brake in which an armature is provided between a yoke having an exciting coil and a brake disk.
[0002]
[Prior art]
Conventional electromagnetic brakes of this type include those used as parking brakes for golf cars, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-181538. This electromagnetic brake is formed as shown in FIG.
[0003]
FIG. 8 is a cross-sectional view showing an example of a conventional electromagnetic brake. In FIG. 8, reference numeral 1 denotes a golf car electromagnetic brake. The electromagnetic brake 1 stops a rear wheel of a golf car (not shown) during parking or emergency stop. The electromagnetic brake 1 is provided at a shaft end of a rotating shaft 2 that rotates together with the rear wheel, and is supported by a mission case 3. Yes.
[0004]
Reference numeral 4 denotes a yoke of the electromagnetic brake 1, 4a denotes an exciting coil built in the yoke, and 5 denotes an armature. The yoke 4 is fixed to the transmission case 3 with fixing bolts 6, and a side plate 7 located at the outer end of the brake (the left end in FIG. 8) is attached with mounting bolts (not shown). Yes. The armature 5 is positioned between the magnetic attracting surface 4b of the yoke 4 and the side plate 7, and is movable in the axial direction (left and right direction in FIG. 8) with respect to the mounting bolt and rotates with respect to the yoke 4. It is mounted in a regulated state. The yoke 4 is provided with a braking spring 8 made of a compression coil spring that urges the armature 5 toward the side plate 7.
[0005]
The yoke 4, the armature 5, and the side plate 7 are each formed to have an annular shape, and the rotating shaft 2 is inserted through each axial center portion. The rotary shaft 2 is rotatably supported by the transmission case 3 by a bearing 9, and a brake disk 11 is mounted on a boss 10 fixed to a shaft end portion so as to be movable in the axial direction by spline fitting. The brake disk 11 includes a disk body 12 and friction plates 13 fixed to both surfaces of the disk body 12, and the friction plate 13 is disposed between the armature 5 and the side plate 7. It is installed.
[0006]
In the conventional electromagnetic brake 1 configured as described above, the yoke 4 is in a non-excited state during parking or emergency stop. In this non-excited state, the armature 5 presses the brake disc 11 toward the side plate 7 by the elastic force of the braking spring 8 to generate a braking force, and the rotating shaft 2 is braked. Further, in the electromagnetic brake 1, the armature 5 is attracted to the yoke 4 against the elastic force of the braking spring 8 when the yoke 4 is excited during traveling, and the braking force disappears and the rotating shaft 2 is removed. Will be able to rotate.
[0007]
The electromagnetic brake 1 is mounted on the inner side of a body cover of a golf car. This vehicle body cover is intended to improve the appearance and prevent rainwater from splashing on the internal components, and cannot completely prevent dust from entering the cover from around the vehicle body. For this reason, the conventional electromagnetic brake is provided with a dust-proof cover 14 that covers the operating portion in order to prevent the dust from entering the sliding contact portion inside.
[0008]
The dust cover 14 is formed to have a bottomed cylindrical shape, and is attached to the side plate 7 with the side plate 7, the brake disk 11, the armature 5, and the end of the yoke 4 being housed therein. It is attached by the use bolt 15.
In addition, the applicant could not find any prior art documents closely related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in the present specification. .
[0009]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-181538 (FIG. 3)
[0010]
[Problems to be solved by the invention]
However, if the end of the yoke 4 and the armature 5 are covered by the dust cover 14 as described above, the wear powder generated by the friction plate 13 of the brake disk 11 slidingly contacting the armature 5, the side plate 7, etc. In some cases, a gap (air gap forming portion) is formed between the armature 5 and the magnetic attraction surface 4b of the yoke 4. The wear powder is not only generated during braking, but the brake disk 11 supported by the spline fitting on the hub 10 is shaken or moved in the axial direction by the vibration of the traveling vehicle body. It is also generated by contacting the side plate 7.
[0011]
Part of the abrasion powder generated in this way falls to the inner peripheral part of the armature 5 and the yoke 4 during traveling, and as shown by the arrows in FIG. Fall from. Further, the wear powder may enter the air gap forming portion from the outer peripheral side through the gap between the armature 5 and the dust cover 14. When the wear powder entering the air gap forming portion is sandwiched between the yoke 4 and the armature 5 during excitation, a gap corresponding to the size of the wear powder is formed between the armature 5 and the magnetic attracting surface 4b. End up.
[0012]
In such a case, since the magnetic attractive force acting on the armature 5 is relatively small even in the excited state, an external force is applied to the armature 5 in a direction away from the yoke 4 due to vibration of the vehicle body. Then, the armature 5 is released from the magnetic attractive force of the yoke 4. That is, the electromagnetic brake is activated when the driver does not intend.
[0013]
The present invention has been made to solve such problems, and to provide an electromagnetic brake having high operation reliability without wear powder or other dust entering between the armature and the yoke. With the goal.
[0014]
[Means for Solving the Problems]
In order to achieve this object, an electromagnetic brake according to the present invention is an electromagnetic brake provided in a state in which the rotation of the armature is restricted with respect to the yoke between a brake disk that rotates with a wheel and an annular yoke. Formed on the armature side end portions of the outer peripheral surface and the inner peripheral surface of the yoke is a continuous ridge extending in the circumferential direction without interruption, and an annular shape in which the yoke is fitted to the end portion of the armature facing the yoke. A concave portion is formed, and a labyrinth seal is formed at a fitting portion between the peripheral wall of the concave portion and the yoke. The concave portion includes an outer peripheral wall and an inner peripheral wall with which the peripheral wall portion of the yoke is fitted, and both the peripheral walls. A flat inner bottom surface facing the magnetic attraction surface of the yoke, and step portions are formed on the outer peripheral wall and the inner peripheral wall, respectively. A first circumferential surface facing the circumferential surface extending in the axial direction of the yoke, an end surface extending from the first circumferential surface in the radial direction of the armature and facing the side surface of the protrusion, and A gap between the end surface and the protrusion of the yoke is as close to 0 as possible when the yoke is in an excited state. Is formed .
According to the present invention, the air gap forming portion between the magnetic attraction surface of the yoke and the armature is sealed to the outside by the labyrinth seal.
[0015]
The electromagnetic brake according to a second aspect of the present invention is the electromagnetic brake according to the first aspect of the present invention, wherein the inner diameter of the armature gradually increases toward the brake disk along the axial direction on the inner periphery of the armature. An inclined surface is formed so as to be larger.
According to this invention, the wear powder easily falls to the brake disc side along the inclined surface.
[0016]
An electromagnetic brake according to a third aspect of the present invention is the electromagnetic brake according to the first or second aspect of the present invention, wherein a side plate against which the brake disk is pressed is provided at one end, and the one end is provided from the outside. A dust-proof cover having a bottom cylindrical shape is covered, and a ventilation hole is formed between the peripheral wall of the dust-proof cover and the side plate.
According to the present invention, the wear powder is easily discharged out of the dust cover through the vent.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, an embodiment of an electromagnetic brake according to the present invention will be described in detail with reference to FIGS.
1 is a side view of a golf car equipped with an electromagnetic brake according to the present invention, FIG. 2 is a plan view of a power unit of a golf car, FIG. 3 is a side view of the same, and FIG. 4 is an enlarged side view of the power unit. FIG. 5 is a cross-sectional view of the electromagnetic brake, which is a cross-sectional view taken along the line V-V in FIG. FIG. 6 is a cross-sectional view showing an enlarged main part. In these drawings, members that are the same as or equivalent to those described with reference to FIG. 8 are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.
[0018]
In FIG. 1, what is indicated by reference numeral 21 is a golf car equipped with an electromagnetic brake 22 (see FIGS. 2 and 3) according to this embodiment. Reference numeral 23 denotes a front wheel, 24 a rear wheel, 25 a steering handle, 26 a front seat, 27 a rear seat, 28 a caddy bag carrier, and 29 a rear body cover.
[0019]
The rear wheel 24 is driven by a power unit denoted by reference numeral 31 in FIGS. The power unit 31 includes a motor 32, a transmission 33, the electromagnetic brake 22, and the like, and is supported by a vehicle body frame 35 via a swing arm 34 so as to be swingable in the vertical direction.
The motor 32 is attached to the right side of the transmission 33 on the front side of the vehicle body so that the axial direction is directed in the left-right direction of the vehicle body. The transmission 33 is provided with an axle 37 (see FIGS. 3 and 4) of the rear wheel 24 by reducing the rotation of the motor 32 by a V-belt type automatic transmission (not shown) provided inside the transmission case 36. A transmission structure is adopted.
[0020]
The electromagnetic brake 22 is of a non-excitation operation type that stops the rear wheel 24 at the time of parking or emergency stop, and is attached to the left end of the vehicle body of the transmission case 36 so as to be positioned on the same axis as the motor 32. It has been. The basic configuration of each member constituting the electromagnetic brake 22, that is, the configuration such as the arrangement position and support structure of each member is the same as that of the conventional electromagnetic brake 1 shown in FIG. 8. Therefore, the description of the basic configuration is omitted here, and only the structural differences from the conventional electromagnetic brake 1 will be described.
[0021]
As shown in FIGS. 5 and 6, the yoke 4 of the electromagnetic brake 22 according to this embodiment has protrusions 41 and 42 formed on the outer peripheral surface 4c and the inner peripheral surface 4d. The protrusions 41 and 42 have a rectangular cross-sectional shape, and are formed so as to extend in series at the end of the yoke 4 on the armature 5 side without interruption in the circumferential direction.
The armature 5 is formed with an annular recess 43 in which the end of the yoke 4 having the protrusions 41 and 42 is fitted at a portion facing the yoke 4. An inner bottom surface 43a of the recessed portion 43 facing the magnetic adsorption surface 4b of the yoke 4 is formed flat, and stepped portions 44 are formed on the outer peripheral wall 43b and the inner peripheral wall 43c , respectively, into which the peripheral wall portion of the yoke 4 is fitted. Has been.
[0022]
As shown in FIG. 6, the stepped portion 44 includes a first peripheral surface 46 facing the peripheral surface 45 (surface extending in the axial direction of the yoke 4) of the protrusions 41 and 42, and the first peripheral surface. An end surface 48 that extends from 46 in the radial direction of the armature 5 (downward in FIG. 6) and faces the side surface 47 of the protrusions 41 and 42, and a second end that extends in the axial direction from the extending side end of the end surface 48. And a peripheral surface 49. Clearances d1 and d2 are formed between the first and second peripheral surfaces 46 and 49 and the yoke 4, and a clearance d3 is formed between the end surface 48 and the yoke 4 (ridges 41 and 42). Has been. This gap d3 is drawn larger than the actual one for easy understanding in FIG. 6, but when the yoke 4 is in an excited state (when the armature 5 is attracted to the yoke 4 by magnetism). It is desirable to form it as close to 0 as possible.
[0023]
In this way, the protrusions 41 and 42 are formed on the yoke 4, and the outer and inner peripheral walls 43b and 43c of the concave portion 43 are formed by forming step portions on the outer peripheral wall 43b and the inner peripheral wall 43c of the concave portion 43. A labyrinth seal 51 is formed at a fitting portion between the yoke 4 and the yoke 4.
[0024]
Therefore, the electromagnetic brake 22 is configured such that the air gap forming portion between the magnetic attraction surface 4b of the yoke 4 and the armature 5 is sealed to the outside by the labyrinth seal 51. Further, it is possible to prevent other dust or the like entering the rear body cover from outside the vehicle from entering the air gap forming portion.
[0025]
In the armature 5 according to this embodiment, an inclined surface 52 is formed on the inner peripheral portion so that the wear powder easily falls from the hollow portion to the brace disk 11 side. The inclined surface 52 is formed so that the inner diameter of the armature 5 gradually increases toward the brake disk 11 side along the axial direction.
[0026]
Further, the brake disc 11 of the electromagnetic brake 22 has a protrusion 53 protruding from the outer periphery of the disc body 12 by so-called harp piercing. The protrusions 53 are provided on both surfaces of the outer peripheral portion of the disk main body 12 to which the friction plate 13 is fixed, and the tip surface is exposed to the outside of the friction plate 13 by being worn to the limit that the friction plate 13 can be used. It is configured as follows.
[0027]
By adopting this configuration, when the projection 53 is exposed as described above, a metal sound is generated by the projection 53 coming into contact with the armature 5 or the side plate 7 during braking. 11 replacement times can be notified.
For this reason, since it can replace | exchange when the limit which can use the brake disc 11 is reached, the brake disc 11 can always be replaced | exchanged at a suitable time.
[0028]
Further, the dustproof cover 14 of the electromagnetic brake 22 is formed so that the axial length of the peripheral wall 54 is shorter than that of the conventional electromagnetic brake, and a part of the yoke 4 and the armature 5 are exposed to the outside. This is because the electromagnetic brake 22 has the labyrinth seal 51 formed at the fitting portion between the yoke 4 and the armature 5 as described above, and dust does not enter the air gap forming portion. Further, the electromagnetic brake 22 has a vent hole 55 formed between the peripheral wall 54 of the dustproof cover 14 and the side plate 7 so that the abrasion powder is easily discharged out of the dustproof cover 14.
[0029]
(Second Embodiment)
The brake disc can be formed as shown in FIG.
FIG. 7 is a cross-sectional view showing another embodiment. In FIG. 7, the same or equivalent members as those described with reference to FIGS. 1 to 6 and FIG. Omitted.
[0030]
In the brake disc 11 shown in FIG. 7, a boss 61 is formed integrally with the disc body 12 and is attached to the rotary shaft 2 via the boss 61. The boss 61 allows the disc main body 12 to move in the axial direction and is movable in the axial direction to the rotary shaft 2 by spline fitting so that the braking force is transmitted from the disc main body 12 to the rotary shaft 2. It is supported.
By adopting this configuration, as shown in FIG. 5 and FIG. 8, the outer diameter of the spline fitting portion becomes smaller and the number of teeth is smaller than when the disc body 12 is connected to the hub 10 by spline fitting. Less. For this reason, the noise which generate | occur | produces when a tooth | gear moves to the circumferential direction by the clearance of a spline fitting part can be reduced.
[0031]
In the first and second embodiments, the example in which the electromagnetic brake according to the present invention is used for a parking brake of a golf car has been shown. However, the present invention can be applied to other vehicle brakes, machine tool brakes, etc. It can also be applied to.
[0032]
【The invention's effect】
As described above, according to the present invention, the air gap forming portion between the magnetic attraction surface of the yoke and the armature can be sealed to the outside by the labyrinth seal. It will not enter the air gap forming part.
Therefore, since the armature is always strongly attracted to the yoke during excitation, it is possible to provide a highly reliable electromagnetic brake that does not operate when not intended.
[0033]
According to the second aspect of the present invention, the wear powder easily falls on the brake disc side along the inclined surface, and it is difficult to enter the air gap forming portion between the armature and the yoke. For this reason, reliability can be further improved.
[0034]
According to the third aspect of the present invention, the wear powder is likely to be discharged out of the dust-proof cover through the vent and is difficult to enter the air gap forming portion between the armature and the yoke. For this reason, reliability can be further improved.
[Brief description of the drawings]
FIG. 1 is a side view of a golf car equipped with an electromagnetic brake according to the present invention.
FIG. 2 is a plan view of a power unit of a golf car.
FIG. 3 is a side view of a power unit of a golf car.
FIG. 4 is an enlarged side view showing a power unit.
FIG. 5 is a cross-sectional view of an electromagnetic brake.
FIG. 6 is an enlarged cross-sectional view showing a main part.
FIG. 7 is a cross-sectional view showing another embodiment.
FIG. 8 is a cross-sectional view showing an example of a conventional electromagnetic brake.
[Explanation of symbols]
4 ... yoke, 5 ... armature, 7 ... side plate, 11 ... brake disk, 22 ... electromagnetic brake, 24 ... rear wheel, 41, 42 ... ridge, 43 ... recessed portion, 43b ... outer peripheral wall, 43c ... inner peripheral wall, 44 ... Step, 51 ... Labyrinth seal.

Claims (3)

In an electromagnetic brake in which an armature (5) is provided between a brake disk that rotates together with a wheel and an annular yoke (4) in a state in which the rotation is restricted with respect to the yoke, an outer peripheral surface (4c) of the yoke At the end on the armature side of the inner peripheral surface (4d), a ridge (41, 42) extending in a series without being interrupted in the circumferential direction is formed,
Forming an annular recess (43) into which the yoke fits at the end of the armature facing the yoke;
A labyrinth seal (51) is formed at the fitting portion between the peripheral wall (43b, 43c) of this recessed portion and the yoke ,
The concave portion includes an outer peripheral wall (43b) and an inner peripheral wall (43c) with which a peripheral wall portion of the yoke is fitted, and a flat inner bottom surface (between the two peripheral walls and facing the magnetic attraction surface (4b) of the yoke). 43a)
Steps (44) are respectively formed on the outer peripheral wall and the inner peripheral wall,
The step portion extends in the radial direction of the armature from the first peripheral surface (46) opposed to the peripheral surface (45) formed of a surface extending in the axial direction of the yoke in the protrusion. An end surface (48) facing the side surface (47) of the ridge, and a second peripheral surface (49) extending in the axial direction from the extending side end of the end surface,
The electromagnetic brake according to claim 1, wherein the gap (d3) between the end face and the protrusion of the yoke is formed to be as close to 0 as possible when the yoke is in an excited state .   2. The electromagnetic brake according to claim 1, wherein an inclined surface is formed on an inner peripheral portion of the armature so that an inner diameter of the armature gradually increases toward the brake disk side along the axial direction.   3. The electromagnetic brake according to claim 1, wherein a side plate against which the brake disk is pressed is provided at one end portion, and a cylindrical dustproof cover with a bottom is covered on the one end portion from the outside. An electromagnetic brake, wherein a vent hole is formed between the side plate and the side plate.

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