JPH063232B2 - Magnetic particle type electromagnetic coupling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic particle type electromagnetic coupling device for transmitting a driving force from a driving body to a driven body via magnetic particles, and particularly to generating a coupling force during non-excitation. Also, it is concerned with improvement for preventing a decrease in coupling force during excitation.

[Conventional technology]

A conventional electromagnetic coupling device of this type has a sectional view shown in FIG. In the figure, 1 is a fixed frame made of a magnetic material, which houses an exciting coil 2 therein, and is provided with a flange 1a for attaching to a fixed portion (not shown). Reference numeral 3 denotes a driving body supported on the inner peripheral portion of this fixed frame via a pair of bearings 7, and a pair of cylindrical driving members 4 and 5 on both sides made of a magnetic material and spaced apart in the axial direction. It is composed of a non-magnetic coupling ring 6 in which these two driving members are integrally coupled, and the outer circumferential surface faces the inner circumferential surface of the stator 1 via an air gap g. Reference numeral 8 denotes a driven shaft supported on the inner peripheral portion of the driving body 3 through a pair of bearings 11. Reference numeral 9 denotes a driven body fixed to the driven shaft, which is made of a disc body of a magnetic material. 9a and 9b are inner end surfaces of the drive members 4 and 5.
4a and 5a and air gaps g ₁ and g that are small in the axial direction, respectively
_They are facing each other through ₂ . Magnetic particles 10 are filled in the air gaps g ₁ and g ₂ . Reference numeral 12 is a seal member fixed to the inner peripheral portion of the driving body 3 and in contact with the outer peripheral surface of the driven shaft 8 to prevent the magnetic particles 10 from scattering. 13 is fitted on the driven shaft 8 and stops each bearing 11 in the axial direction. A pair of retaining rings, 14 are retaining rings fitted on the driving member 5 and axially stopping the one bearing 7.

The operation of the above conventional device is as follows. When the driving body 3 coupled to the driving source (not shown) is rotating,
When an exciting current is passed through the exciting coil 2, a magnetic flux Φ is generated as shown by the dotted line in FIG. 9, and the magnetic particles 10 in the air gaps g ₁ and g ₂ are magnetized and coupled in a chain shape in the axial direction, Driven body 9
Is rotated integrally with the driving body 3 or while sliding, and the driven shaft 8
Rotate together.

Thus, by controlling the exciting current, the torque can be controlled, and there is an advantage that it can be used in a continuous sliding state within the allowable temperature rise.

FIG. 10 shows a state in which the driving body 3 is rotated at high speed without excitation. Due to the centrifugal force generated by the high speed rotation, the magnetic particles 10 have both end surfaces 4
It will be offset toward the outer periphery of the void between a and 5a.

When excitation is started at this high speed rotation, as shown in FIG. 11, a part of the magnetic particles 10 is axially coupled at the air gaps g ₁ and g ₂ due to the magnetic flux Φ, but the outer periphery of the void portion is The magnetic particles 10 in the part are axially coupled by the magnetic flux passing therethrough,
It does not contribute to torque transmission to the driven body 9.

[Problems to be solved by the invention]

In the conventional electromagnetic coupling device as described above, when a non-excited state continues for a long time at a high speed, the magnetic particles 10 group which are biased to the outer peripheral portion of the space between both end surfaces 4a and 5a are solidified, and Despite the excitation, there is a problem that a connecting force is generated between the driven body 9 and the driving body 3 and torque is transmitted.

Further, when excitation is started while the driving body 3 continues to rotate at high speed, the magnetic particles on the outer peripheral portion of the space between both end surfaces 4a and 5a are started.
10 is directly connected, and there is a part that does not contribute to torque transmission,
There has been a problem that the magnetic particles 10 connecting the air gaps g ₁ and g ₂ are reduced and the transmission torque is reduced.

By coping with this and increasing the amount of the magnetic particles 10, the coupling force can be increased, but the generation of the coupling force in non-excitation is
There is a problem that the problems caused by the relatively low speed rotation occur, and the increased magnetic particles 10 often come into contact with the seal member 12, which shortens the life of the seal member.

The present invention has been made to solve such a problem, prevents the generation of a coupling force during non-excitation in high-speed rotation, and prevents a reduction in coupling force during excitation. An object of the present invention is to obtain a magnetic particle type electromagnetic coupling device in which disconnection of the coupling force when the excitation is cut off is improved.

[Means for solving problems]

The electromagnetic coupling device according to the present invention is provided with annular notches at the outer peripheral portions of both inner end surfaces of the drive member, which face each other in the axial direction of the drive members, to form escape portions for magnetic particles, and The bottom surface of the notch is formed as an inclined surface having a smaller diameter on the inner end surface side.

[Action]

In the present invention, the magnetic particles generated by the centrifugal force in the high speed rotation of the drive body during non-excitation are accommodated in the escape portion formed between the annular cutout portions of both drive members of the drive body, and are connected. The driven body remains stopped without producing force. When the driving body starts to be excited in a high-speed rotation state, the magnetic particles contained in the escape portion of the driving body are smoothly drawn into the air gaps on both sides of the driven body by magnetic attraction, and the coupling force Starts up faster.

〔Example〕

FIG. 1 is a sectional view of a magnetic particle type electromagnetic coupling device according to the present invention, in which 1, 2, 6 to 14, 1a, 9a and 9b are the same as those of the conventional device. Reference numeral 20 denotes a driving body, which is arranged at a distance in the axial direction and has a pair of cylindrical driving members 21 and 22 made of a magnetic material, and a non-magnetic coupling ring 6 integrally coupling these driving members. It consists of Both drive members 21,
The driven body 9 is arranged between the inner end surfaces 21a, 22a facing each other of 22 via small air gaps g ₁ , g ₂ . Drive member
On the outer peripheral portions of the inner end surfaces 21a and 22a of the reference numerals 21 and 22, annular cut portions 21b and 22b that are widened in the axial direction and the radial direction are formed.

The annular cutouts 21b and 22b of the drive members 21 and 22 are shown in an enlarged view in FIG. FIG. 2 shows a state in which the driving body 20 rotates at a high speed and is not excited. The bottom surfaces of the cutouts 21b and 22b are inclined surfaces 21 whose inner end surfaces 21a and 22a have a small diameter (outer diameter A).
It is formed on c and 22c. A relief portion 23 having a wide width c due to a space formed by the notches 21b and 22b and the inner circumferential portion of the coupling ring 6.
The magnetic particles 10 are accommodated by the centrifugal action when the driving body 20 is not excited by high-speed rotation. Corners between the outer circumferential portion (outer diameter A) of the inner end surfaces of the drive members 21 and 22 and the inclined surfaces 21c and 22c are rounded by chamfered portions 21d and 22d formed by arcuate surfaces, and accommodated in the escape portion 23. This facilitates the magnetic attraction movement of the magnetic particles in the state to the air gaps g ₁ and g ₂ by the excitation. The chamfered portions 21d and 22d may be sloped surfaces that drop the corners in addition to the arcuate surfaces.

The outer diameter A of the inner end surfaces 21a and 22a is made smaller than the outer diameter B of the driven body 9 so that the air gap g from the escape portion 23 of the magnetic particles 10 is reduced.
_It is made easy to move to ₁ and g ₂ .

Next, the operation of the apparatus of the above-described embodiment will be described. The coupling action by excitation is similar to that of the above-mentioned conventional device, and the action at the time of high-speed rotation, which has been a problem of the conventional device, will be described.

When the drive body 20 is rotated at high speed by the drive source and is not excited,
The state shown in FIG. 2 is obtained. The magnetic particles 10 move radially due to centrifugal force, and are distributed and accommodated in the escape portion 23 in a sufficiently large space. Even if the high-speed rotation continues for a long time, the magnetic particles 10 group will not be solidified due to the large accommodation volume of the escape portion 23. In this way, a coupling force that exceeds mechanical loss as in the conventional case does not occur. In this escape section 23,
A sufficient amount of magnetic particles 10 are housed in the air gaps g ₁ and g ₂ to be distributed over the entire surface.

When excited in such a high-speed rotation state, the escape part
In No. 23, the width C in the axial direction is sufficiently wide, the magnetic resistance is large, and the magnetic flux passing therethrough is small, so that the magnetic particles 10 in this void are not connected and contain a sufficient amount of magnetic particles 10. But there is no problem.

Thus, as shown in FIG. 3, the magnetic particles 10 are moved by magnetic attraction into the air gaps g ₁ and g ₂ through which a large amount of magnetic flux passes by excitation, but the cut portions 21b and 22b have inner end surfaces 21a and 21b.
The inclined surfaces 21c and 22c are formed toward a and 22a, and the corners are smoothed by the chamfered portions 21d and 22d, and the inner diameters of the inner end surfaces 21a and 22a are larger than the outer diameter of the driven body 9. Since the outer diameter of the outer peripheral portion (chamfered portion) is small, the magnetic particles 10 from the escape portion 23
Is to be rectified, and the air gap g ₁ ,
It is sucked into the g ₂ very smoothly.

Thus, as shown in FIG. 4, the magnetic particles 10 are entirely distributed in the air gaps g ₁ and g ₂ on both sides of the driven body 9 and are in a completely connected state to transmit torque. As a result, the transmission torque does not decrease even in the high speed rotation state.

In addition, when the annular notches 21b and 22b of the drive members 21 and 22 are simply formed in a rectangular shape and the inclined surfaces 21c and 22c and the chamfered portions 21d and 22d are not provided, or the inclined surfaces and the chamfered portions are formed. Is provided, but the inner end surfaces 21a, 2a are larger than the outer diameter of the driven body 9.
When the outer diameter of the outer peripheral portion (chamfered portion) of 2a is large, the wide escape portion 23 does not cause the magnetic particles 10 group to be solidified by centrifugal force, but it is excited when rotating at an extremely high speed. However, due to the large inflow resistance of the magnetic particles 10, there is a problem that a predetermined connecting force cannot be obtained because the magnetic particles 10 do not enter the air gaps g ₁ and g ₂ .

In the case of the conventional device shown in FIG. 9 and in the case where the annular notch is simply a rectangular notch and the inclined surface is not provided,
The transmission torque measurement result with the device of one embodiment of the present invention,
It is shown in the following table. It should be noted that the ratio of the transmission torque when the driving body is 200 rpm is 100 is shown.

FIG. 5 is an enlarged sectional view of a relief portion of a driving member of a driving body according to a second embodiment of the present invention, showing a high speed rotation non-excitation state. Inner end surfaces 31a, 3 of both drive members 31, 32 of the drive body 20
The outer peripheral portion of 2a is provided with annular notch portions 31b and 32b which are cut in the axial direction and the radial direction, and the bottom surface portion extending from the inner surface to the inner end surfaces 31a and 32a is formed as an inclined surface on the circular arc surfaces 31c and 32c. It is formed and connected smoothly. The magnetic particles 10 are moved and accommodated in the escape portion 23 formed between the notches 31b and 32b by centrifugal force.

When excited from this state, as shown in FIG. 6, the magnetic particles 10 are smoothly magnetically attracted and flowed into the air gaps g ₁ and g ₂ to be in a connected state.

FIGS. 7 (a) and 7 (b) show a third embodiment of the present invention. One of the driving bodies 20 has a driving member 41 on the outer peripheral portion of the inner end surface 41a.
An annular cutout portion 41b is provided intermittently at a plurality of positions in the circumferential direction, and a bottom surface portion has an inclined surface 41c having a smaller diameter on the inner end surface 41a side.
Is formed, and a chamfered portion 41d having an arc surface is provided at the corner. The other drive member (not shown) that faces the other drive member
Also, a similar notch is provided.

FIG. 8 shows a fourth embodiment of the present invention. The drive members 51, 52 of the drive body 20 include the inner end faces 51a, 52a on the outer periphery thereof.
Annular cutouts 51b and 52b, which are formed with steep slopes 51c and 52c with a small diameter on the 51a and 52a side, are provided, and a relief portion is provided between them.
I am 23. Since the inclined surfaces 51c and 52c are steeply inclined and the corners with the inner end surfaces 51a and 52a are large obtuse angles, chamfering is not required. However, this corner may be further chamfered.

Although the fixed frame 1 is provided and the exciting coil 2 is incorporated in the above-described embodiment, the driven body may be made thick and the exciting coil may be incorporated. In this case, a slip ring is provided on the driven shaft side to supply power. Also, in this case,
It is also possible to omit the fixing frame by connecting both driving members of the driving body at the outer peripheral portion to form a magnetic path on the outer peripheral side.

Further, both drive members may be thickened in the radial direction, the exciting coil may be housed between them, and the fixing frame may be omitted. In this case, the drive member is provided with a slip ring.

Furthermore, although the driven body 9 is separate from the transmission shaft 8,
The driven body may be integrally formed, and the driven body may have a constitutional shape other than that of the above embodiment, which may be modified if necessary.

Furthermore, in the above embodiment, the driving body 20 is a pair of driving members.
Although the case where it is configured by 21 and 22 is shown, it is also applicable to the case where it is configured by a plurality of pairs of driving members.

〔The invention's effect〕

As described above, according to the present invention, annular notch portions that are notched in the axial direction and the radial direction are provided on the outer peripheral portions of both inner end surfaces of the drive member that face each other in the axial direction. A magnetic particle escape portion is formed in between, and the bottom surface portion of the cutout portion is formed into an inclined surface having a smaller diameter on the inner end surface side, and further, the outer peripheral portion of the inner end surface from the outer diameter of the driven body. Since the outer diameter is made small, no coupling force is generated in the case of non-excitation at high speed rotation, and a predetermined coupling force is obtained in the case of excitation at high speed rotation as in the case of low speed rotation.

Further, when the excitation is shut off from the excited state at a high speed, the magnetic particles are rapidly accommodated in the escape portion, and the disconnection of the coupling force becomes good.

Further, when the magnetic flux flows into the air gap portion from the escape portion by magnetic attraction, it moves smoothly with less resistance, magnetic particles are less likely to be damaged by pressure, and the life is extended. is there.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a magnetic particle type electromagnetic coupling device according to the present invention, and FIGS. 2 to 4 are views from non-excitation at a high speed rotation of opposing inner end face annular notches of both drive members of FIG. FIG. 5 and FIG. 6 are enlarged cross-sectional views showing the excitation state in the order of operation, FIG. 5 and FIG. FIG. 8 is a sectional view and a front view of an inner end face annular cutout portion of one drive member showing a third embodiment of the present invention, and FIG. 8 is a drive member showing a fourth embodiment of the present invention. FIG. 9 is an enlarged sectional view of an annular cutout portion of the opposing inner end surface portion, FIG. 9 is a longitudinal sectional view of a conventional electromagnetic coupling device, and FIGS. 10 and 11 are opposing inner end surface portions of both drive members of FIG. It is an expanded sectional view which shows a non-excitation and an excitation state in high speed rotation. 2 ... Excitation coil, 9 ... Driven body, 9a, 9b ... Side surface, 10 ... Magnetic particle, 20 ... Drive body, 21, 22, 31, 32, 41, 51, 52 ... Drive member, 21a, 22a, 31a, 32a, 41a, 51a, 52a ... Inner end surface, 21b, 22b, 31b, 32b, 41b, 51b, 52b ... Annular notch, 21c, 22c, 41c, 51c, 52c ... Inclined surface, 21d, 22d, 41d
... chamfered portion, 23 ... relief addition unit, 31c, 32c ... arcuate inclined surfaces, g _{1, g} 2 _... air gap should be noted that the same reference characters denote the same or corresponding parts.

Claims (5)

[Claims] 1. A drive body composed of at least a pair of drive members in which both inner end faces are opposed to each other with an interval in the axial direction and are joined together, and a disk body, and both drive members of the drive bodies are provided. Open an air gap in the axial direction between the inner end faces,
And, a driven body which is arranged with an open space on the outer circumferential side, magnetic particles filled in the air gap portions of both of the above, and a magnetic flux is generated by being energized, and the both air gaps from the driving member are generated. In an electromagnetic coupling device including an exciting coil for magnetizing the magnetic particles, which is passed through a magnetic path passing through the driving body via an annular cutout portion on the outer peripheral portion of each inner end surface of the both driving members facing each other. To form a bottom surface portion of the annular notch portion into an inclined surface where the inner end surface side is small,
The magnetic particle type electromagnetic coupling device is characterized in that an outer diameter of a corner portion between the inclined surface and the inner end surface is smaller than an outer diameter of the driven body. 2. The magnetic particle type electromagnetic coupling device according to claim 1, wherein the inclined surface of the annular notch portion is formed as an inclined surface, and a corner between the inclined surface and the inner end surface is chamfered. . 3. The magnetic particle type electromagnetic coupling device according to claim 1, wherein the inclined surface of the annular notch is formed by an arc surface. 4. The magnetic particle type electromagnetic coupling device according to claim 1, wherein the inclined surface of the annular notch is formed by a steep inclined surface toward the inner end surface. 5. The magnetic particle type electromagnetic coupling device according to any one of claims 1 to 4, wherein the annular notch is formed so as to be interrupted in a circumferential direction.