JP4525046B2 - Electromagnetic ball clutch - Google Patents

Description

The present invention relates to an electromagnetic clutch that transmits and cuts off rotational torque between a primary wheel and a secondary rotor on a concentric shaft by electromagnetic operation, and more particularly, an electromagnetic ball clutch using a ball for torque transmission. Regarding improvements.

Conventionally, as an electromagnetic clutch, an electromagnetic dry type single-plate clutch that transmits torque using a frictional force between a rotor on the input side and an armature on the output side, or a rotor on the input side and the output side is used. 2. Description of the Related Art There are known electromagnetic tooth clutches and the like that transmit torque by engaging teeth (toothes) respectively provided on an armature.
In these electromagnetic clutches, the armature is attracted to the rotor side by the electromagnetic force generated by energizing the exciting coil to transmit torque between the rotor and the armature, and the armature is separated from the rotor by turning off the energization. The transmission of torque is cut off.

By the way, the conventional electromagnetic dry single-plate clutch needs to increase the diameters of the rotor and the armature in order to increase the transmission torque, and there is a problem that both the mass and the size increase, resulting in an increase in cost.
On the other hand, since the electromagnetic tooth clutch is a complete meshing type, it is difficult to provide a function as a torque limiter, and slip control cannot be performed when an overload is applied.

Patent Document 1 discloses a ball clutch that uses a plurality of balls to control transmission and disconnection of torque between a first rotating member and a second rotating member disposed around the first rotating member. Is disclosed.
Japanese Examined Patent Publication No. 6-29619 Fig. 4

However, since the ball clutch described in Patent Document 1 displaces the ball in the radial direction by moving the clutch connecting / disconnecting ring in the axial direction, operating force required for switching increases when the clutch connecting / disconnecting ring is translated. .
In the invention of Patent Document 1, the operating point of the shift arm is set at an eccentric position, one side of the clutch connecting / disconnecting ring is tilted by operating the shift arm, and the outward pressing force of the sphere by the spline-like protrusion is utilized. By similarly tilting the other side of the clutch connecting / disconnecting ring, the clutch connecting / disconnecting ring is moved with a small operating force, but it is difficult to incorporate the same structure into a small electromagnetic clutch. In addition, since the size of the sphere is relatively large with respect to the entire size, there is a problem that the movement stroke of the sphere is large and the apparatus is enlarged.

The present invention has been made in view of the above-described problems of the prior art, and can transmit a large torque without increasing the size in the radial direction, and switches between torque transmission and cutting by electromagnetic force. It is an object of the present invention to provide an electromagnetic ball clutch having a configuration suitable for the above.

The electromagnetic ball clutch according to claim 1 of the present invention is configured to transmit and block rotational torque using a ball between a primary wheel and a secondary rotor on a concentric shaft by electromagnetic operation.
The rotor has a disk part perpendicular to the axial direction and a large-diameter cylindrical part extending in the axial direction from the periphery of the disk part, and a fixed part that rotatably supports the rotor is switched between energized and de-energized. Thus, the exciting coil for switching between the action and non-action of the electromagnetic force is fixed. An armature that rotates integrally with the wheel and that can be displaced in the axial direction is disposed inside the large-diameter cylindrical portion of the rotor on the opposite side of the excitation coil across the rotor.
This armature is urged in a direction away from the disk portion of the rotor by the urging means, and is displaced in the axial direction by switching between energization and de-energization of the excitation coil.
In addition, a plurality of balls are arranged between the outer peripheral surface of the armature and the inner peripheral surface of the large-diameter cylindrical portion of the rotor, and a part of the balls is fitted to either the outer peripheral surface or the inner peripheral surface. A concave portion to be held is formed. On the other hand, either when the armature is attracted to the disk side by energizing the excitation coil, or when the armature is attracted to the wheel side when the excitation coil is not energized or only during one axial collision conditions for transmitting rotational torque between the engaging rotor and the wheel to the ball is formed.

Further, a plurality formed at equal angular intervals a recess on the outer circumferential surface of the A Machua, are formed over the entire periphery of the protrusion at equal angular intervals on the inner peripheral surface of the large diameter cylindrical portion of the rotor.

Further, the bottom surface of the recess formed in A Machua, is inclined inwardly toward the rotor side, that part of the rotational direction of the torque acting on the ball so as to act in a direction to separate the armature from the rotor Features.

The electromagnetic ball clutch according to a second aspect is characterized in that, on the premise of the first aspect, the diameter of the ball is set in a range of 1/50 to 1/30 of the diameter of the rotor.

According to the configuration of claim 1, the engagement between the ball and the ridge enables transmission of a large torque without increasing the size in the radial direction, and the ball and the ridge are relatively axially disposed. By displacing them, it is possible to obtain a configuration suitable for switching between transmission and cutting of torque by electromagnetic force.

Further, by inclining the bottom surface of the recess, the torque of the direction of separating the armature from the rotor by the rotation occurs, it is possible to have a function as a torque limiter in clutch slip control when overloaded It becomes possible.

If the diameter of the ball is set as shown in claim 2 , the armature stroke for switching between engagement and disengagement of the ball and the protrusion can be shortened, the size of the clutch in the axial direction can be reduced, and The stress applied to the biasing means can be reduced, and the magnetic attractive force of the exciting coil can be set small. That is, it is possible to reduce the size and power consumption of the exciting coil.

Embodiments of an electromagnetic ball clutch according to the present invention will be described below with reference to the drawings.
1 is a partially longitudinal side view showing an electromagnetic ball clutch according to a first embodiment of the present invention, FIG. 2 is a longitudinal side view of a rotor of the electromagnetic ball clutch shown in FIG. 1, and FIG. FIG. 4 is a front view showing the armature of the electromagnetic ball clutch shown in FIG. 1.

First embodiment:
As shown in FIG. 1, the electromagnetic ball clutch 1 according to the first embodiment includes a primary wheel 10 that is rotated by a rotational torque transmitted from the outside, and a wheel 10 that is disposed concentrically with the wheel 10. And a rotor 20 on the secondary side, and the rotational torque of the wheel 10 is transmitted to and cut off from the rotor 20 by electromagnetic operation.

The wheel 10 is rotatably attached to the output shaft 30 and is positioned by the retaining ring 11 so as not to slide in the axial direction.

On the other hand, the rotor 20 is fixed so as not to rotate so as to rotate integrally with the output shaft 30 and not to slide in the axial direction.
As shown in FIG. 2, the rotor 20 includes a small-diameter cylindrical portion 21 that surrounds the outer periphery of the output shaft 30, and a disk portion 22 that rises perpendicularly to the axial direction from the end of the small-diameter cylindrical portion 21 on the wheel 10 side. And a large-diameter cylindrical portion 23 extending in the axial direction from the periphery of the disk portion 22.
The rotor 20 is rotatably supported by a fixed portion 40 via a seat bearing (not shown).

Further, on the inner peripheral surface of the large-diameter cylindrical portion 23 of the rotor 20, as shown in FIGS. 2 and 3, the ridges 24 projecting toward the output shaft 30 are 30 over the entire circumference at equal angular intervals of 12 °. It is formed in the place. Each ridge 24 has gentle slopes on both sides in the rotational direction, the central portion forms a partial cylindrical surface, and a groove extending in the axial direction is formed between a pair of adjacent ridges 24. Is formed.
The length of the protrusion 24 in the axial direction is set to about half of the width of the inner peripheral surface of the large diameter cylindrical portion 23. That is, the inner peripheral surface of the large-diameter cylindrical portion 23 is a cylindrical surface with no unevenness on the wheel 10 side, but is a cylindrical surface with unevenness on the half on the fixed portion 40 side.

The fixed portion 40 is configured by mounting an excitation coil 42 wound around a bobbin 41 in a ring-shaped yoke 43 as a whole with a U-shaped cross section that opens to the wheel 10 side, and housing these in a frame 44. Has been. The exciting coil 42 switches between the action and non-action of electromagnetic force by switching between energization and non-energization.

An armature 50 that rotates integrally with the wheel 10 and that can be displaced in the axial direction with respect to the wheel 10 is attached to the opposite side of the exciting coil 42 across the rotor 20.
As shown in FIG. 1, the armature 50 is disposed in a space inside the large-diameter cylindrical portion 23 of the rotor 20.
The armature 50 is urged in a direction away from the disk portion 22 of the rotor 20 by a release spring 60 that is an urging means. When the excitation coil 42 is energized, the electromagnetic force generated in the excitation coil 42 causes the disk of the rotor 20 to be energized. When it is not energized, it is attracted to the wheel 22 side by the urging force of the release spring 60.

A plurality of balls 70 are arranged between the outer peripheral surface of the armature 50 and the inner peripheral surface of the large-diameter cylindrical portion 23 of the rotor 20. On the outer peripheral surface of the armature 50, as shown by dotted lines in FIG. 4, recesses 51 are formed in which the balls 70 are partially fitted and held at three positions at intervals of 120 °. The ball 70 held by the recess 51 is displaced along with the axial displacement of the armature 50, and when the armature 50 is attracted to the disk portion 22 side by energizing the exciting coil 42, It enters the formed groove and transmits the rotational torque of the wheel 10 to the rotor 20.

The diameter of the ball 70 is 1 mm in this example, and the diameter of the rotor 20 (40 m in this example).
m) is set to 1/40. The diameter of the ball 70 is set to a size necessary and sufficient to transmit a predetermined torque when engaged with the ridge, based on the height of the ridge 24, the accuracy of each component, and the like.
Specifically, it is desirable to set in the range of 1/50 to 1/30 of the diameter of the rotor 20. If the ratio is less than 1/50, the allowable range of component accuracy is narrowed. If it is greater than 1/30, the armature stroke is increased when the clutch is switched.

Next, the operation of the electromagnetic ball clutch 1 according to the first embodiment will be described based on FIG. 5, FIG. 6, FIG. 7, and FIG.
5 and 6 are diagrams showing the relationship between the rotor and the armature when the torque of the electromagnetic ball clutch 1 is cut, respectively. FIGS. 7 and 8 are diagrams showing the relationship between the rotor and the armature when transmitting the torque, respectively. . In these figures, FIGS. 5 and 7 are longitudinal side views, respectively, and FIGS. 6 and 8 are cross-sectional views taken along lines BB in FIGS. 5 and 7, respectively.

When the exciting coil 42 is not energized and no electromagnetic force is applied, the armature 50 is set at a position away from the disk portion 22 of the rotor 20 by the biasing force of the release spring 60 as shown in FIG. .
At this time, as shown in FIG. 6, the protrusion 24 and the ball 70 are not engaged, the clutch is in a disconnected state, and the rotational torque of the wheel 10 is not transmitted to the rotor 20. In other words, even if the wheel 10 is braked, the rotor 20 can rotate freely.

On the other hand, when the exciting coil 42 is energized and electromagnetic force is applied, the armature 50 is attracted to the disk portion 22 side of the rotor 20 against the urging force of the release spring 60 as shown in FIG.
As a result, the ball 70 enters and engages with the groove between the adjacent protrusions 24, and as shown in FIG. 8, the protrusions 24 and the recesses on the rear side with respect to the rotation direction (indicated by arrows in the figure). 51, the rotor 20 and the armature 50 are connected to each other.
As a result, the clutch is engaged and the rotational torque of the wheel 10 is transmitted to the rotor 20. In other words, if the wheel 10 is braked, the rotor 20 is also braked.

According to the first embodiment described above, the engagement between the ball 70 and the ridge 24 enables transmission of a large torque without increasing the radial size, and the ball 70 and the ridge. Thus, a configuration suitable for switching between transmission and cutting of torque by electromagnetic force can be obtained.

Further, since the diameter of the ball 70 is small, the stroke of the armature 50 for switching the engagement and disengagement between the ball 70 and the protrusion 24 can be shortened, the size of the clutch in the axial direction can be reduced, and the release spring. The stress applied to 60 can be reduced, and the magnetic attractive force of the exciting coil 42 can be set small.
That is, the exciting coil 42 can be reduced in size and power consumption.

Contrary to the first embodiment, the concave portion may be formed on the inner peripheral surface of the large-diameter cylindrical portion 23 of the rotor 20, and the protrusion may be formed on the outer peripheral surface of the armature 50.
In this case, the axial length of the ridge is about half the axial thickness of the armature 50,
When the armature 50 is attracted to the wheel 10 with the power off, it does not engage with the ball 70, and when the armature 50 is attracted to the disk portion 22 side of the rotor 20 with the power on, the arm 70 engages with the ball 70 and torque. May be configured to transmit.

Further, as in the first embodiment, torque is not transmitted only when the armature 50 is attracted to the disk portion 22 side by energizing the exciting coil 42, but not energizing the exciting coil 42. In some cases, the torque may be transmitted only when the armature 50 is attracted to the wheel 10 side.

Second embodiment:
Next, an electromagnetic ball clutch according to a second embodiment will be described with reference to FIG.
FIG. 9 is a longitudinal sectional side view showing a main part of the second embodiment. The difference from the first embodiment is only the structure of the recess 81 formed in the armature 80, and the other configuration is the same as that of the first embodiment. Therefore, only the differences will be described.

As shown in FIG. 9, in the armature 80 of the second embodiment, the bottom surface of the recess 81 is inclined inward toward the rotor 20, and a part of the torque in the rotational direction acting on the ball 70. Is configured to act in a direction in which the armature 80 is pulled away from the rotor 20.
In this way, by inclining the bottom surface of the recess 81, torque is generated in the direction in which the armature 80 is pulled away from the rotor 20 due to rotation, so that the clutch can have a function as a torque limiter and an overload is applied. Slip control becomes possible. Assuming that the inclination of the bottom surface of the recess 81 with respect to the axial direction is θ, the limit torque can be arbitrarily set by appropriately setting θ.

The electromagnetic ball clutch of the present invention can be applied as, for example, a clutch of a sliding door for automobiles because it can transmit a large torque while being small and light and low cost.

1 is a partially longitudinal side view showing an electromagnetic ball clutch according to a first embodiment of the present invention. It is a vertical side view of the rotor of the electromagnetic ball clutch shown in FIG. It is a front view which shows the rotor of FIG. It is a front view which shows the armature of the electromagnetic ball clutch shown in FIG. It is a vertical side view which shows the relationship between the rotor and armature at the time of the torque cutting | disconnection of the electromagnetic ball clutch shown in FIG. It is sectional drawing which follows the BB line of FIG. It is a vertical side view which shows the relationship between the rotor and armature at the time of torque transmission of the electromagnetic ball clutch shown in FIG. It is sectional drawing which follows the BB line of FIG. It is a vertical side view which shows the principal part of the electromagnetic ball clutch concerning the 2nd Embodiment of this invention.

Explanation of symbols

1: Electromagnetic ball clutch 10: Wheel 20: Rotor 21: Small diameter cylindrical part 22: Disk part 23: Large diameter cylindrical part 24: Projection 30: Output shaft 40: Fixed part 41: Bobbin 42: Excitation coil 43: Yoke 44: Frame 50, 80: Armature 51, 81: Recess 60: Release spring 70: Ball

Claims (2)

In an electromagnetic ball clutch that transmits and shuts off rotational torque between the primary wheel and the secondary rotor on the concentric shaft by electromagnetic operation,
The rotor has a disk part perpendicular to the axial direction, and a large-diameter cylindrical part extending in the axial direction from the periphery of the disk part,
An excitation coil that switches between the action and non-action of electromagnetic force by switching between energization and de-energization is fixed to the fixed portion that rotatably supports the rotor,
An armature that rotates integrally with the wheel and that can be displaced in the axial direction is disposed inside the large-diameter cylindrical portion of the rotor on the opposite side of the excitation coil across the rotor, and the armature is biased Is biased in a direction away from the disk portion of the rotor by the means, and is displaced in the axial direction by switching between energization / non-energization of the excitation coil,
A plurality of balls are disposed between the outer peripheral surface of the armature and the inner peripheral surface of the large-diameter cylindrical portion of the rotor, and the balls are partially fitted to either the outer peripheral surface or the inner peripheral surface A recess is formed to be held, and on the other hand, when the armature is attracted to the disk portion side by energizing the exciting coil, or when the energizing coil is not energized, the armature moves to the wheel. only when one of when it is adsorbed to the side, and impact conditions of the axial direction is formed for transmitting rotational torque between the wheel and the rotor engaged with said ball,
A plurality of the recesses are formed at equiangular intervals on the outer peripheral surface of the armature, and the protrusions are formed over the entire circumference at equiangular intervals on the inner peripheral surface of the large-diameter cylindrical portion of the rotor,
The bottom surface of the recess formed in the armature is inclined inward toward the rotor side, and a part of the rotational torque acting on the ball acts in the direction of pulling the armature away from the rotor. An electromagnetic ball clutch. The electromagnetic ball clutch according to claim 1 , wherein the diameter of the ball is in a range of 1/50 to 1/30 of the diameter of the rotor .

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