JP2002345206A - Motor with built-in electromagnetic brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor having a highly reliable electromagnetic brake, which can be formed thinner with higher fitting accuracy and higher yield, can prevent adverse effect of leakage magnetic flux of electro-magnetic brake for the motor, and can remarkably extend the operation life of the electromagnetic brake. SOLUTION: The electromagnetic brake is configured with an armature 12 which can be moved in the axial direction with an attraction through feeding electrical power to the electromagnetic coil 11 and an reaction of a spring, a hub 13 fixed to a rotor rotating shaft 15c, and a lining 14 located between the armature 12 and hub 13. A rotating part of the electromagnetic brake accommodates a projected part 13a of the hub 13 into a recessed part 15d provided at the center of the rotor yoke 15b in the electro-magnetic brake side only with the hub 13 provided with the fixed lining 14 in order to fix the projected part 13a to the rotor rotating shaft 15c with a screw 13b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor with a built-in electromagnetic brake that is mounted on a device that operates at a high tact such as a component mounter and that repeatedly performs acceleration and deceleration operations.

[0002]

2. Description of the Related Art Conventionally, there are a motor with a brake and a motor without a brake as a motor used as a drive source of industrial equipment, and a motor with a brake is used for an application which requires a holding force particularly in a stopped state. ing.

[0003] As a brake of a motor with a brake,
A backlash type electromagnetic brake in which a hub is shrunk at a predetermined position on a rotating shaft is general, and will be described with reference to the drawings.

In FIG. 2, 21 is an electromagnetic coil wound around a yoke 21a, 22 is an armature, 23 is a rotating plate having linings 23a fixed on both sides, 24 is a hub, 25 is a fixed plate, 26 is a rotor, and 27 is a stator. , 28
a and 28b are bearings, 29 is an encoder, and the hub 24 is fixed to the rotating shaft 26a of the rotor 26.

When the electromagnetic coil 21 is in a non-energized state, the rotating plate 23 having the armature 22 and the lining 23a fixed to both surfaces thereof by a plurality of springs (not shown) on the side of the electromagnetic coil 21 is pressed by the fixed plate 25 together. Is fixed.

When the electromagnetic coil 21 is energized, the yoke 21a
Becomes an electromagnet, the armature 22 is attracted to the yoke 21 a of the electromagnetic coil 21 while compressing the spring, and the rotating plate 23 sandwiched and fixed between the armature 22 and the fixing plate 25 is opened, so that the rotor 26 is It becomes rotatable. There is a slight clearance in the axial direction and the radial direction between the outer peripheral portion of the hub 24 and the inner peripheral portion of the rotating plate 23. When the rotor 26 rotates, the rotating plate 23 rotates in a state of being in close contact with one side due to centrifugal force.

[0007] The hub 24 is shrunk by face-to-face contact with the step of the rotating shaft 26a, and simultaneously secures the perpendicularity to the rotating shaft 26a and the holding force.

For this reason, by appropriately designing the hub thickness, the axial length of the electromagnetic brake has been suppressed, and the motor has been made thinner.

[0009]

However, in the above-mentioned conventional structure, in order to further reduce the thickness, it was necessary to design the thickness of the hub as thin as possible just before the limit at which mechanical strength could be secured. However, when the hub alone is made thinner, it is difficult to secure dimensional accuracy (parallelism and perpendicularity) with respect to the inner diameter, which has been a factor that deteriorates the yield in the manufacturing process.

In order to reduce the thickness of the electromagnetic brake, it is common to secure the required slot cross-sectional area by reducing the inner diameter of the yoke of the electromagnetic coil and increasing the outer diameter. Therefore, the clearance with the rotating shaft is secured to a predetermined value or more in order to reduce the influence of the leakage magnetic flux due to energization of the electromagnetic brake. If the clearance is reduced, the leakage magnetic flux is biased to the magnetic flux distribution of the rotor magnet via the rotating shaft, and the cogging torque may increase. Further, the bearing may be magnetized by the leakage magnetic flux, thereby shortening the life or causing disturbance to the magnetic encoder.

Further, a predetermined clearance is provided in the radial direction between the rotary plate and the hub so that the rotary plate slides smoothly in the axial direction when the electromagnetic brake is operated (attracted). Appeared as backlash,
This backlash appears as backlash noise (noise) when the motor is accelerated or decelerated.

Further, the inner peripheral portion of the rotary plate tends to wear due to repeated acceleration / deceleration of the motor, and the backlash tends to increase gradually. When the angular acceleration of the motor is excessive, or when the motor is repeatedly used for a long time at high tact. In the above, there is a risk that the rotating plate is deformed due to acceleration and deceleration and cannot be opened, and furthermore, it may be broken by fatigue.

The present invention has been made to solve the above-mentioned conventional problems, and has a high mounting accuracy, a good yield and a low profile. It is an object of the present invention to provide a highly reliable motor with a built-in electromagnetic brake that can dramatically extend its life.

[0014]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a motor in which an electromagnetic brake is built in between bearings rotatably supporting a rotor. An armature movable in the axial direction by a repulsive force of a spring, a hub having a convex portion and fixed to a rotor rotating shaft, a lining disposed between the armature and the hub, a rotor magnet, a rotor yoke, and a rotor rotating shaft; And a concave portion is provided in a central portion of the rotor yoke on the electromagnetic brake side, and a convex portion of the hub is housed and fixed to reduce the thickness of the electromagnetic brake built-in motor.

[0015] Further, since the rotor rotating shaft is made of a non-magnetic material, the influence of the leakage magnetic flux of the electromagnetic brake can be eliminated.

Further, since the backlash can be eliminated by fixing the lining to the hub, the noise can be reduced and the life of the electromagnetic brake can be extended.

[0017]

According to a first aspect of the present invention, there is provided a motor having a built-in electromagnetic brake, wherein the electromagnetic brake is provided between bearings for rotatably supporting a rotor. An armature movable in the axial direction by a suction force and a repulsion force of a spring by energization of a power supply, and a hub having a convex portion and fixed to a rotor rotating shaft,
A lining provided between the armature and the hub, a rotor comprising a rotor magnet, a rotor yoke, and a rotor rotation shaft were provided.A concave portion was provided in a center portion of the rotor yoke on the electromagnetic brake side, and a convex portion of the hub was housed and fixed. The provision of the projections makes it easier to secure the mounting accuracy of the hub, improves the yield, and further reduces the thickness by housing the projections of the hub in the recesses of the rotor yoke.

Further, in the motor with a built-in electromagnetic brake according to the present invention, the rotor rotating shaft is made of a non-magnetic material, so that it is possible to prevent the leakage magnetic flux of the electromagnetic brake from being generated via the rotor rotating shaft.

According to a third aspect of the present invention, there is provided a motor having a built-in electromagnetic brake, wherein the electromagnetic brake has a lining fixed to a hub, and the hub is fixed to a rotor rotating shaft. The life of the brake can be greatly extended.

Further, in the component mounting machine equipped with the motor with a built-in electromagnetic brake according to any one of claims 1 to 3, the space for installing the motor with a built-in electromagnetic brake in the component mounting machine can be reduced, and backlash. Operation at high tact. Further, since the life of the motor with the built-in electromagnetic brake can be extended, the reliability of the component mounter is improved.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 11 is an electromagnetic coil wound around a yoke 11a, 12 is an armature, 13 is a hub,
The projection 13a is provided. 14 is a lining, 15 is a rotor, a rotor magnet 15a, a rotor yoke 15
b, and a non-magnetic rotor rotating shaft 15c. 1
6a and 16b are bearings which rotatably support the rotor rotating shaft 15c and are attached to the brackets 17a and 17b. Reference numeral 18 denotes a stator having a winding, and 19 denotes an encoder.

The electromagnetic brake includes an armature 12 that can move in the axial direction due to an attractive force generated by energizing an electromagnetic coil 11 and a repulsive force of a spring, a hub 13 fixed to a rotor rotating shaft 15 c, and an armature 12 between the armature 12 and hub 13. The lining 14 is provided.

The rotating part of the electromagnetic brake includes a lining 14
Is fixed only to the hub 13, and the protrusion 13 a of the hub 13 is provided.
Is housed in a recess 15d provided at the center portion of the rotor yoke 15b on the electromagnetic brake side, and is fixed to the rotor rotating shaft 15c with screws 13b.

Here, the operation of the motor with a built-in electromagnetic brake will be described.

When the motor stops rotating, the electromagnetic coil 11 is not energized, and the lining 14 is
The armature 12 is contacted and fixed by the repulsive force of a plurality of springs (not shown) on one side. One surface of the lining 14 is fixed to the hub 13 with an adhesive, and the hub 13 is fixed to the rotor rotation shaft 15 c, so that the rotor 15 is fixed by the armature 12.

When the electromagnetic coil 11 is energized, the yoke 11a becomes an electromagnet, the armature 12 compresses the spring and is attracted to the yoke 11a of the electromagnetic coil 11, and the lining 14 and the hub 13 are released from the armature 12 to form a gap. Is done. Thereby, the rotor 15 becomes rotatable, and the rotor 15 can be rotated by applying a voltage to the winding of the stator 18 at an appropriate timing.

By the way, in order to realize a smooth braking operation, it is necessary to mount the hub 13 on the rotor rotating shaft 15c with high accuracy. Naturally, the perpendicularity and runout of the bonding surface of the lining 14 with respect to the inner diameter of the hub 13 are processed with high precision. However, the provision of the convex portion 13a on the hub 13 makes it possible to lengthen the holding portion and mount the hub 13 with high precision.

However, if the protrusion 13a is provided, the axial dimension is not reduced. However, as in the present invention, the protrusion 13a of the hub 13 is housed in the recess 15d provided at the center of the rotor yoke 15b on the electromagnetic brake side. Therefore, the dimension in the axial direction is shortened, and the thickness can be reduced.

Further, the friction surface of the lining 14 for securing the static friction torque (holding torque) is reduced from the conventional both surfaces to one surface, and the sliding area of the lining 14 is reduced to reduce the rotor inertia of the electromagnetic brake. In this state, in order to secure the same static friction torque, the spring pressure is increased for the purpose of increasing the friction torque per unit area, but the attraction force of the electromagnetic coil 11 also needs to be increased by increasing the ampere-turn.

Here, in order to reduce the thickness of the electromagnetic brake and increase the sectional area of the electromagnetic coil 11, the yoke 11a
The inner diameter is reduced and the outer diameter is increased. As a result, the clearance between the yoke 11a of the electromagnetic coil 11 and the rotor rotating shaft 15c is reduced, and if the rotor rotating shaft 15c is made of a magnetic material, the leakage magnetic flux of the electromagnetic brake passes through the rotor rotating shaft 15c and It adversely affects the main magnetic field, increases the cogging torque, and magnetizes the bearing, adversely affecting the bearing life.

If the rotor shaft 15c is made of a non-magnetic material such as stainless steel as in the present invention, the above-mentioned adverse effects do not occur.

Further, since the rotating portion of the electromagnetic brake is only the hub 13 to which the lining 14 is fixed, the rotor rotating shaft 1
5c, there is no clearance, and high-tact repetitive operation is possible like a component mounter. Further, the life of the electromagnetic brake can be greatly extended, and the reliability of the motor with a built-in electromagnetic brake can be improved.

[0034]

As is apparent from the above embodiment, according to the first aspect of the present invention, the convex portion of the hub is housed and fixed in the concave portion of the rotor yoke. Can be secured, and a smooth braking operation can be performed.

According to the second aspect of the present invention, since the rotor rotating shaft is made of a non-magnetic material, the leakage magnetic flux of the electromagnetic brake is generated via the rotor rotating shaft, the cogging torque is deteriorated, and the bearing is magnetized. Can be prevented.

According to the third aspect of the present invention, since the hub and the lining are fixed and the hub is fixed to the rotor rotating shaft, there is no backlash of the electromagnetic brake, and rapid acceleration and deceleration of the motor can be used. Become. Further, the life of the electromagnetic brake can be significantly extended.

According to the fourth aspect of the present invention, if the motor with a built-in electromagnetic brake of the present invention is mounted on a component mounter, the space for installing the motor with a built-in electromagnetic brake in the component mounter can be reduced, and There is no rush, so high reliability and high tact can be realized. In addition, it can contribute to noise reduction and longer life of the component mounter.

[Brief description of the drawings]

FIG. 1 is a sectional view of a motor with a built-in electromagnetic brake showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional motor with a built-in electromagnetic brake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electromagnetic coil 11a Yoke 12 Armature 13 Hub 13a Convex part 14 Lining 15 Rotor 15a Rotor magnet 15b Rotor yoke 15c Rotor rotation axis 15d Concave part

Claims (4)

[Claims] 1. A motor having an electromagnetic brake built in between bearings rotatably supporting a rotor, wherein an armature movable in an axial direction by an attraction force by energizing an electromagnetic coil having a yoke and a repulsive force of a spring; A hub fixed to the rotor rotating shaft having a portion, a lining disposed between the armature and the hub, and a rotor comprising a rotor magnet, a rotor yoke, and a rotor rotating shaft, and a central portion of the rotor yoke on the electromagnetic brake side. A motor with a built-in electromagnetic brake, characterized in that a recess is provided in the housing and the protrusion of the hub is housed and fixed. 2. The motor with a built-in electromagnetic brake according to claim 1, wherein the rotor rotation shaft is made of a non-magnetic material. 3. The motor with a built-in electromagnetic brake according to claim 1, wherein the electromagnetic brake has a lining fixed to a hub. 4. A component mounting machine equipped with the electromagnetic brake built-in motor according to claim 1.