JP2002364679A - Electromagnetic coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently utilize an electromagnet by preventing the magnetic flux of the electromagnet for engaging a clutch from leaking. SOLUTION: This electromagnetic coupling comprises a case-like torque transmission member (rotating case) 3, a shaft-like torque transmission member (inner shaft 5), a clutch 7 for connecting the torque transmission members to each other, and an electromagnet 19 for disengaging and engaging the clutch 7 through a magnetic path. The case-like torque transmission member 3 comprises an axial one side wall part (rotor) 27 forming a part of the magnetic path and a torque transmission member (cylindrical member) 25 having the clutch 7 disposed thereon. A clearance part 35 for preventing magnetic flux from leaking is provided between the one side wall part 27 in an axial direction and the torque transmission member 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic coupling used for a power transmission system of a vehicle.

[0002]

2. Description of the Related Art FIG.
Such a driving force transmission device 301 is described.

[0003] The driving force transmission device 301 includes a rotating case 30.
3, inner shaft 305, main clutch 307,
It comprises a ball cam 309, a pressure plate 311, a cam ring 313, a pilot clutch 315, an armature 317, an electromagnet 319, and the like.

[0004] The driving force transmission device 301 is disposed by dividing a propeller shaft on the rear wheel side which is cut off during two-wheel driving in a four-wheel drive vehicle, and a rotating case 303 is connected to a front propeller shaft and an inner shaft. 3
05 is connected to the rear propeller shaft.

When the electromagnet 319 is excited, the armature 3
17 is sucked and presses the pilot clutch 315 to be engaged. When the pilot clutch 315 is engaged,
The driving force of the engine is applied to the ball cam 309 by the generation of the pilot torque, and the main clutch 307 is pressed by the generated cam thrust force, so that the driving force transmission device 301
And the driving force is transmitted to the rear wheel side, and the vehicle enters a four-wheel drive state.

When the excitation of the electromagnet 319 is stopped,
The pilot clutch 315 is released and the ball cam 30 is released.
9, the main thrust force is released, the main clutch 307 is released, the connection of the driving force transmission device 301 is released, the rear wheel side is disconnected, and the vehicle enters a two-wheel drive state.

The rotating case 303 includes the main clutch 30
7 includes a cylindrical member 321 connected thereto and a rotor 323. The rotor 323 forms a part of a magnetic path of the electromagnet 319, and the cylindrical member 321 prevents leakage of magnetic flux from the magnetic path. Made of stainless steel.

[0008]

SUMMARY OF THE INVENTION Driving force transmission device 301
In the case of an electromagnetic coupling which is intermittently operated by using an electromagnet as described above, if the magnetic flux leaking from the magnetic path to the outside is large, the necessary pilot torque cannot be obtained, and the main clutch 307
Therefore, there is a possibility that a desired driving force cannot be transmitted to the wheels because a desired fastening force cannot be obtained.

Therefore, in the driving force transmission device 301, the leakage of the magnetic flux is prevented by forming the cylindrical member 321 of the rotating case 303 from stainless steel (non-magnetic material) or the like as described above.

[0010] However, stainless steel is expensive and has a problem that the cost increases accordingly.

[0011] Further, stainless steel is difficult to cut and form, as compared with ordinary alloy steel for shafts, and when used for shaft materials, nitriding treatment or the like is required to improve abrasion resistance. However, there is a problem that the cost is further increased.

On the other hand, if the size of the electromagnet 319 is increased in order to compensate for the leakage of the magnetic flux, the current consumption increases, the load on the battery and the generator system increases, and the entire device becomes larger and heavier. Affects gender.

When the size of the electromagnet 319 is increased, a controller for controlling the exciting current of the electromagnet 319 needs to cope with the increase of the current, which further increases the cost.

Accordingly, the present invention structurally prevents the leakage of magnetic flux, allows the use of a low-cost torque transmitting member having a large strength, and increases the size of the electromagnet and the size and weight of the device associated therewith. The aim is to provide an electromagnetic coupling that prevents the impact on vehicle-mounted performance due to the above.

[0015]

According to a first aspect of the present invention, there is provided an electromagnetic coupling comprising a case-like torque transmitting member, a shaft-like torque transmitting member, a clutch connecting these members, and an intermittent operation of the clutch via a magnetic path. And the case-shaped torque transmitting member includes an axial side wall forming a part of a magnetic path and a torque transmitting member on which a clutch is disposed. It is characterized in that a gap is provided between the member and the member to prevent the leakage of magnetic flux.

Thus, in the electromagnetic coupling according to the first aspect, the magnetic flux leakage of the electromagnet is prevented by the gap provided between the one axial side wall on the magnetic path side and the torque transmitting member on the clutch side.

Accordingly, unlike the conventional cylindrical member 321 (rotating case 303), there is no need to use a non-magnetic material for the outer torque transmitting member, thereby avoiding a significant increase in cost.

Further, in addition to using a material other than a non-magnetic material, for example, low-cost steel for machine structural use as the outer torque transmitting member, sufficient torque can be transmitted by preventing leakage of magnetic flux. Becomes possible.

Furthermore, since the loss of the exciting current due to the leakage of the magnetic flux is reduced, the load on the battery or the generator system which is the power source of the electromagnet is reduced, and the adjustment of the controller is not required. The cost increase associated with is also avoided.

Further, the weight is reduced by the provision of the gap portion, so that the vehicle mountability is improved.

According to a second aspect of the present invention, there is provided the electromagnetic coupling according to the first aspect, wherein the gap is provided at least between the clutch and a clutch-side surface of the electromagnet. As a feature, the same operation and effect as the configuration of claim 1 can be obtained.

Further, since the gap is provided between the clutch and the clutch-side surface of the electromagnet, leakage of the magnetic path can be reliably prevented with a simple structure.

According to a third aspect of the present invention, there is provided the electromagnetic coupling according to the first or second aspect, wherein the gap is set to a direction away from the clutch than the clutch-side surface of the electromagnet. As a feature, the same operation and effect as the configuration of claim 2 can be obtained.

Further, since the gap is set in a direction away from the clutch than the surface of the electromagnet on the clutch side,
Leakage of magnetic flux from the electromagnet can be more effectively prevented.

According to a fourth aspect of the present invention, there is provided the electromagnetic coupling according to any one of the first to third aspects, wherein the centering portion of one axial side wall portion is located on a side farther from the clutch than the gap portion. It is characterized by having been provided, Claims 1 to
The same operation and effect as the configuration 3 can be obtained.

Further, since the centering portion of the one axial side wall portion is provided, the one axial side wall portion can be centered and supported while preventing magnetic flux leakage due to the gap portion. Operation can be ensured.

Moreover, since the centering portion is provided on the side farther from the clutch than the gap portion, no magnetic flux leaks from the centering portion to the case-like torque transmitting member side.

According to a fifth aspect of the present invention, there is provided an electromagnetic coupling according to any one of the first to fourth aspects, comprising a pilot mechanism and a cam mechanism, wherein the pilot mechanism is operated and stopped by an electromagnet. When the pilot mechanism is actuated, a torque is applied to the cam mechanism, and the clutch is connected by the generated pressing force, so that the same operation and effect as those of the first to fourth aspects can be obtained.

Further, the electromagnetic coupling of this configuration is
Since a large torque transmission capacity can be obtained by the boosting function of the cam mechanism, it is optimal for a power transmission device for a vehicle.

Further, since the non-magnetic material prevents the magnetic force of the electromagnet from being lost and a necessary pilot torque can be obtained by the pilot mechanism, for example, when the electromagnetic coupling is used in a power transmission system of a vehicle, the electromagnetic coupling is not used. The desired driving force can be transmitted to the wheels in accordance with the change in the running conditions, and the loss of the exciting current can be reduced.

Further, since the size and weight of the electromagnet are prevented, the in-vehicle performance of the electromagnetic coupling is improved.

As described above, the effect of preventing the magnetic flux from leaking out of the electromagnet according to the present invention is particularly large in this configuration including the pilot mechanism and the cam mechanism.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An electromagnetic coupling 1 (first embodiment of the present invention) will be described with reference to FIGS.

The electromagnetic coupling 1 is characterized in that
It is provided between the rear wheel side (rear differential side) and the prime mover side (transfer) side which are separated during two-wheel drive in a four-wheel drive vehicle. Also,
The left and right directions are the left and right directions of the vehicle, and the right side of FIG. 1 corresponds to the front of the vehicle (motor side). In addition, members and the like without reference numerals are not shown.

The electromagnetic coupling 1 and the rear differential (a differential device for distributing the driving force of the prime mover to the left and right rear wheels) are arranged in this order in the front-rear direction, and are housed in a differential carrier.

The electromagnetic coupling 1 includes a rotating case 3
(Case-shaped torque transmitting member), hollow inner shaft 5 (shaft-shaped torque transmitting member), multi-plate type main clutch 7
(Clutch), ball cam 9 (cam mechanism), pressure plate 11, cam ring 13, multi-plate pilot clutch 15, armature 17, electromagnet 19, controller and the like.

The rotary case 3 includes a power transmission shaft 23 and a cylindrical member 25 (a torque transmission member on which a clutch is disposed), each of which is made of a strong material such as steel for machine structural use.
The rotor 27 is made of an iron-based alloy (magnetic material) (one side wall in the axial direction forming a part of the magnetic path).

A flange 29 is formed on the power transmission shaft 23, and the power transmission shaft 23 and the cylindrical member 25 are welded at the flange 29. A ring-shaped convex portion 31 inserted into the front end portion of the inner shaft 5 is formed concentrically on the flange portion 29.

The rotor 27 is screwed to the inner periphery of the cylindrical member 25 by a screw portion 33 provided between the rotors. A lock nut 47 is screwed into the screw portion 33 of the rotor 27. The lock nut 47 presses the rear end of the cylindrical member 25 and applies a thrust force to the cylindrical member 25 and the rotor 27 by the double nut function to prevent each of them from loosening, thereby enhancing the fixing function.

A gap 35 is provided between the rotor 27 and the cylindrical member 25. The gap 35 is a cylindrical member 25
Further, it is formed so as to cover substantially the entire outer peripheral surface of the rotor 27 from the portion screwed with the lock nut 47 to the pilot clutch 15. By forming such a gap 35, the magnetic flux from the electromagnet 19 is transferred to the cylindrical member 25.
Thus, the armature 17 can be efficiently sucked by the electromagnet 19.

The size of the gap 35 is selected depending on the correlation with the attractive force of the electromagnet 19.

The graph 171 in FIG. 2 shows the correlation between the attractive force of a general electromagnet and the distance to the attracted object. As the distance from the electromagnet increases, the attractive force of the electromagnet sharply increases. It turns out that it falls to.

Therefore, by utilizing this relationship and providing the gap 35 between the rotor 27 and the cylindrical member 25, it is possible to prevent the leakage of the magnetic path.

The power transmission shaft 23 protrudes forward from the differential carrier, and is connected to the transfer side via a companion flange, a joint, a propeller shaft and the like connected to the spline portion 49. The driving force of the prime mover is transmitted to the rotating case 3 via these power transmission systems.

The inner shaft 5 penetrates the rotary case 3 from the rear, and the front end thereof is formed on the projection 3 of the power transmission shaft 23.
1 and radially centered. The rear end of the inner shaft 5 is provided with a ball bearing 57.
And the inner shaft 5 is axially positioned with respect to the rotor 27 via a snap ring 59.

As described above, the inner shaft 5 is radially centered at the front end by the convex portion 31 of the power transmission shaft 23 and radially centered at the rear end by the ball bearing 57. Of the inner shaft 5 and the inner shaft 5
Vibration of the electromagnetic coupling 1 due to vibration of the electromagnetic coupling 1 is prevented.

Further, between the inner shaft 5 and the rotor 27, an X-ring 61 having an X-shaped cross section is disposed inside the ball bearing 57 to prevent oil leakage.

A drive pinion shaft is connected to a spline portion 63 formed on the inner periphery of the inner shaft 5. A drive pinion gear is formed integrally with the drive pinion shaft, and the drive pinion gear meshes with a ring gear on the rear differential side. The rotation of the inner shaft 5 is transmitted to the rear differential via these power transmission systems.

The power transmission shaft 23 is provided inside the rotating case 3.
The oil is injected from an oil hole 65 formed in the flange portion 29 of the first embodiment. After oil is injected, the oil hole 65 is sealed by press-fitting a steel ball 67.

The hollow inner shaft 5 is defined by a wall 69, and a capacity increasing space 71 for increasing the amount of oil to be filled is formed. The flange portion 29 of the power transmission shaft 23 is provided with capacity increasing spaces 73 and 75 for increasing the amount of filled oil. In the capacity increasing spaces 71, 73, and 75, similarly to other portions inside the rotating case 3, the injected oil and air are stored. The capacity increasing space 71 communicates with the main clutch 7 through four radial flow paths 77 formed in the inner shaft 5.

The main clutch 7 is disposed between the rotating case 3 (cylindrical member 25) and the inner shaft 5, and its outer plate 79 is connected to a spline portion 81 formed on the inner periphery of the cylindrical member 25. The inner plate 83 is connected to a spline portion 85 formed on the outer periphery of the inner shaft 5. Further, a spacer 87 is disposed in front of the main clutch 7, and a spline portion 8 is provided.
Connected to 1.

The ball cam 9 is mounted on the pressure plate 1
1 and the cam ring 13.

The pressure plate 11 has an inner periphery connected to a spline portion 85 of the inner shaft 5.
The main clutch 7 receives the thrust force of the ball cam 9.
Is pressed and fastened to the rotating case 3 via the spacer 87.

The cam ring 13 is disposed on the outer periphery of the inner shaft 5 so as to be relatively rotatable.
A thrust bearing 89 and a washer 91 that receive a cam reaction force of the ball cam 9 are disposed between the thrust bearing 89 and the rotor 27.

The pilot clutch 15 is mounted on the rotating case 3
The outer plate 93 is connected to the spline portion 81 of the cylindrical member 25, and the inner plate 95 is connected to a spline portion 97 formed on the outer periphery of the cam ring 13. Have been.

The armature 17 is arranged between the pressure plate 11 and the pilot clutch 15 and has an outer periphery movably connected to a spline portion 81 of the cylindrical member 25.

The core 99 of the electromagnet 19 penetrates through an appropriate air gap into a ring-shaped recess 101 formed in the rotor 27 and is supported on the rotor 27 by a double-sided seal type ball bearing 103. .

The leg 109 of the dust cover 107 is engaged with the groove 105 provided in the core 99. The dust cover 107 is connected to the differential carrier side and keeps the electromagnet 19 (core 99) from rotating.

The lead wire 111 of the electromagnet 19 is wired along the inside of the dust cover 107, and the grommet 1
13 is drawn out of the differential carrier and connected to a controller (not shown).

The rotor 27, pilot clutch 15 and armature 17 form a magnetic path for the electromagnet 19.

The rotor 27 is divided into a radially outer side and an inner side by a stainless steel ring 115 which is a nonmagnetic material. Also, each plate 9 of the pilot clutch 15
3,95 at the radial position corresponding to the ring 115,
A plurality of cutouts and a bridge portion connecting these cutouts are provided in the circumferential direction. These rings 1
The cutout 15 prevents the magnetic flux from being short-circuited on the magnetic path.

The controller detects the turning traveling from the vehicle speed, the steering angle, the lateral G, and the like, or performs the excitation of the electromagnet 19, the control of the excitation current, the stop of the excitation, and the like according to the road surface condition.

When the electromagnet 19 is excited, a magnetic flux loop 119 is formed in the above-mentioned magnetic path, the armature 17 is attracted, and the pilot clutch 15 is pressed and fastened with the rotor 27 to generate pilot torque.

When the pilot torque is generated, a transmission torque is applied to the ball cam 9 from the cam ring 13 connected to the rotating case 3 via the pilot clutch 15 and the pressure plate 11 on the inner shaft 5 side, and receives the generated cam thrust force. Pressure plate 1
1 moves forward and presses the main clutch 7 to fasten it.

When the electromagnetic coupling 1 is connected in this manner, the driving force of the prime mover for rotating the rotating case 3 rotates the rear differential from the inner shaft 5 via a power transmission system such as the drive pinion shaft and the like. The vehicle is distributed to the left and right rear wheels to be in a four-wheel drive state, so that the running performance on a rough road and the stability of the vehicle body are improved.

At this time, when the exciting current of the electromagnet 19 is controlled, the slip of the pilot clutch 15 changes, the cam thrust force of the ball cam 9 changes, and the pressing force of the main clutch 7 changes, and the driving force sent to the rear wheels changes. , The driving force distribution ratio between the front and rear wheels can be controlled.

For example, if such a control of the driving force distribution ratio is performed during a turning operation, the controllability and stability of the vehicle can be greatly improved.

When the excitation of the electromagnet 19 is stopped, the pilot clutch 15 is released, the cam thrust force of the ball cam 9 disappears, the main clutch 7 is released, the connection of the electromagnetic coupling 1 is released, and the rear differential is disconnected. Then, the vehicle enters a two-wheel drive state of front-wheel drive.

As described above, by providing the gap portion 35 between the cylindrical member 25 through which the magnetic flux passes and the rotor 27 forming the magnetic path of the electromagnet 19, the leakage of the magnetic flux toward the cylindrical member 25 is prevented. Further, by using a paper clutch plate for the inner plate 83, leakage of magnetic flux between the rotating case 3 (the cylindrical member 25) and the inner shaft 5 is prevented.

Even if a ball bearing 51 having no magnetic flux interruption function is arranged between the front end of the inner shaft 5 and the rotating case 3 (convex portion 31), this part is
Since it is far from the magnetic path of No. 9, the leakage of magnetic flux is practically negligible.

As described above, since the magnetic force loss of the electromagnet 19 is prevented and the magnetic force is efficiently guided to the armature 17, the pilot torque required by the pilot clutch 15 is obtained. It is possible to transmit a desired driving force to the side according to a change in running conditions of the vehicle or the like.

The oil sealed in the rotating case 3 is
Due to the centrifugal force caused by the rotation of the electromagnetic coupling 1, it circulates through the inside, and the inner periphery of the main clutch 7, ball cam 9, pilot clutch 15, spline portions 81, 85, 97, thrust bearing 89, washer 91, cam ring 13. Is supplied to the sliding surface of the inner shaft 5 and the outer periphery of the inner shaft 5, the X-ring 61, and the like to sufficiently lubricate and cool them.

The oil in the capacity increasing space 71 flows into the main clutch 7 by centrifugal force from the radial flow path 77 of the inner shaft 5 and is given to the sliding surface between the outer plate 79 and the inner plate 83. The lubrication and cooling effects are further improved.

Further, an oil hole 121 is formed in each inner plate 83 of the main clutch 9 to promote the movement of oil to the sliding surfaces of the plates 79 and 83, and to improve the lubrication and cooling effects thereof. ing.

Further, a through hole 117 is formed in the pressure plate 11 to reduce the movement resistance due to oil to improve the operation response of the main clutch 7, and this through hole 117 serves as an oil flow path. The movement of oil toward the ball cam 9 and the pilot clutch 15 is promoted, and the lubrication and cooling effects thereof are improved.

As described above, the rotating case 3 and the inner shaft 5 are connected to the projection 31, the ball bearing 57,
Since it is positioned in the axial direction via the snap ring 59 and the like, the main clutch 7 (the plate 79 and the plate 83), the pilot clutch 15 (the plate 93 and the plate 95), the pressure plate 11 and the armature 17, etc. Uneven wear due to abnormal contact is prevented, and the clearance and function of the ball cam 9 (pilot function and pressing function of the main clutch 7) are normally maintained.

The rotating case 3 and the inner shaft 5
Is centered by the convex portion 31 and the needle bearing 57, so that the run-out of the inner shaft 5 and the vibration of the electromagnetic coupling 1 are prevented.

Thus, the electromagnetic coupling 1 is configured.

As described above, the electromagnetic coupling 1 has a gap 35 formed over substantially the entire outer periphery of the rotor 27 except for the screwed portion with the cylindrical member 25, and the pilot clutch 15 , The rotor 27 and the cylindrical member 25 do not come into contact with each other, and leakage of the magnetic flux of the electromagnet 19 to the cylindrical member 25 side is prevented. Therefore, unlike the conventional example, the rotating case 3 (cylindrical member 25) does not need to be made of a non-magnetic material such as stainless steel, thereby avoiding a significant increase in cost.

Further, by using the mechanical case steel, which is a material other than the non-magnetic material, for the rotating case 3, the cost can be reduced, sufficient strength can be obtained, and a large driving force can be transmitted. Was.

Further, the loss of the exciting current due to the leakage of the magnetic flux is reduced.

Therefore, in order to compensate for the leakage of the magnetic flux, the electromagnet 1
It is not necessary to increase the size of the electromagnet 9, so that the size and weight of the electromagnet 19 can be avoided, and the provision of the gap portion 35 makes the electromagnet 19 lighter.

FIG. 3 is a characteristic diagram in which the torque output from the electromagnetic coupling 1 with respect to the current supplied to the electromagnet 19 is measured. A graph 173 shows this embodiment in which the gap 35 is provided. 175 indicates a conventional coupling having no gap. Since the torque continuously increases from the start of the current supply to the stop of the current supply, each curve has a closed loop shape. From FIG. 3, it can be seen that even with the same current value, the torque of this embodiment is large, and the gap portion 35 has the effect of preventing the leakage of magnetic flux.

Since the exciting current does not increase due to no leakage of the magnetic flux as described above, the controller does not need to be adjusted, and an increase in cost due to this is also prevented.

Further, the screw portion 33 by the lock nut 47 is used.
The relative position between the cylindrical member 25 and the rotor 27 is normally maintained by the loosening prevention function, so that the function of the electromagnetic coupling 1 is also normally maintained.

The electromagnetic coupling 1 can obtain a large torque transmission capacity by the boosting function of the ball cam 9, and is therefore most suitable for a vehicle power transmission device as described above.

[Second Embodiment] FIG. 4 shows an electromagnetic coupling 131 according to a second embodiment.

The electromagnetic coupling 131 has the features of the first, second, fourth, and fifth aspects. The electromagnetic coupling 1 is applied to a four-wheel drive vehicle using the electromagnetic coupling 1 of the first embodiment. Is used in place of Note that the left side of FIG. 4 corresponds to the front of the vehicle (the prime mover side), and members without reference numerals and the like are not shown.

Hereinafter, differences will be described while giving the same reference numerals to members having the same functions as those of the electromagnetic coupling 1.

The electromagnetic coupling 131 includes the rotating case 3, the inner shaft 5, the main clutch 7, the ball cam 9, the pressure plate 11, the cam ring 13, the pilot clutch 15, the armature 17, the electromagnet 19,
It consists of a controller.

The rotating case 3 includes a cylindrical member 25, a power transmission shaft 23, and a rotor 27. The power transmission shaft 23 is fixed to the front surface of the cylindrical member 25 by bolts 123. The power transmission shaft 23 does not protrude in the form of a shaft, but instead has a spline portion 1 formed on the inner surface.
25 is connected to the transfer side by connecting the shaft.

The inner shaft 5 penetrates into the rotating case 3, the rear end of which is supported by the rotor 27 via a needle bearing 131, and the front end of which is supported by the cylindrical member 25 by means of a ball bearing 133.

Further, oil leakage from between the inner shaft 5 and the cylindrical member 25 is prevented by the X rings 127 and 129 provided on both sides in the length direction of the inner shaft 5.

A seal ring 135 is provided between the rotor 27 and the cylindrical member 25 to prevent oil from leaking between them.

A gap 137 is provided between the rotor 27 and the cylindrical member 25. The gap 137 is
9 is provided between the surface 139 on the main clutch 7 side and the pilot clutch 15. That is, it is shorter than the gap 35 of the first embodiment. Accordingly, the rear end of the rotor 27 becomes longer, and a contact portion 141 that contacts the cylindrical member 25 is formed.

The contact portion 141 extends away from the main clutch 7. When the contact portion 141 comes into contact with the cylindrical member 25, the contact portion 141 serves as a centering portion for centering the rotor 27. This allows
The rotor 27 is radially centered by the contact portion 141.

In the second embodiment, the gap 137 is provided to prevent the leakage of the magnetic flux of the electromagnet 19, and the same effect as the electromagnetic coupling 1 of the first embodiment can be obtained. In addition to this, the contact portion 1 formed on the rotor 27
Since the center of the rotor 27 is centered in the radial direction by the contact of the rotor 41 with the cylindrical member 25, the rotation of the rotating case 3 can be performed smoothly. Particularly, since the contact portion 141 is provided on the side farther from the main clutch 7 than the gap portion 137, the magnetic flux of the electromagnet 19 can be prevented from leaking from the contact portion 141 to the cylindrical member 25, and the magnetic flux can be efficiently reduced. It is possible to use it.

In the second embodiment, the contact portion 141
Is formed integrally with the rotor 27, but a ring-shaped member may be disposed between the cylindrical member 25 and the rotor 27.

If this ring-shaped member is formed of a non-magnetic material, it is possible to prevent leakage of the magnetic path from the contact portion 141, which is more effective. As the non-magnetic material, any material can be used as long as it has non-magnetic and desired strength, such as non-magnetic stainless steel, aluminum alloy, copper alloy, plastic, and hard rubber.

[Third Embodiment] FIG. 5 shows an electromagnetic coupling 151 according to a third embodiment.

This electromagnetic coupling 151 has the features of the first, third, and fifth aspects, and is a four-wheeled vehicle using the electromagnetic coupling 1 of the first embodiment or the electromagnetic coupling 131 of the second embodiment. These electromagnetic couplings 1 and 131 are used in driving vehicles instead of these. In addition,
The left side of FIG. 5 corresponds to the front of this vehicle (the prime mover side), and members without reference numerals and the like are not shown.

Hereinafter, differences will be described while giving the same reference numerals to members having the same functions as those of the electromagnetic coupling 1 and the electromagnetic coupling 131.

The electromagnetic coupling 151 of this embodiment
Also, the gap 153 is formed between the rotor 27 and the cylindrical member 25 to prevent the magnetic flux of the electromagnet 19 from leaking to the cylindrical member 25 side.

The gap 153 extends from the pilot clutch 15 in the direction of the electromagnet 19 to prevent the leakage of magnetic flux, but further behind the surface 139 of the electromagnet 19 on the side of the main clutch, that is, on the side away from the main clutch 7. Extends to. Thereby, the portion where the rotor 27 contacts the cylindrical member 25 is reduced, and the magnetic flux of the electromagnet 19 is more reliably prevented from leaking to the cylindrical member 25 side.

[0105]

According to the electromagnetic coupling of the first aspect of the present invention, a gap is provided between one axial side wall portion on the magnetic path side and the clutch side torque transmitting member constituting the case-like torque transmitting member. By preventing the magnetic flux leakage of the case-shaped torque transmitting member, it is not necessary to use a non-magnetic material.
It becomes possible to use a strength material for the case-shaped torque transmitting member, thereby reducing costs and transmitting sufficient torque.

In addition, the loss of the exciting current of the electromagnet is reduced, and the adjustment of the controller is not required, so that the cost increase can be avoided.

According to the electromagnetic coupling of the second aspect, the same effect as the configuration of the first aspect can be obtained.

Since the gap is provided between the clutch and the surface of the electromagnet on the clutch side, the leakage of the magnetic path can be reliably prevented with a simple structure.

The electromagnetic coupling according to the third aspect can provide the same effect as the configuration according to the second aspect.

Since the gap extends farther from the clutch than the surface of the electromagnet on the clutch side, leakage of magnetic flux from the electromagnet can be more effectively prevented.

According to the electromagnetic coupling of the fourth aspect, the same effect as the configuration of the first to third aspects can be obtained.

Further, since the centering portion of the one axial side wall portion is provided, the one axial side wall portion can be centered and supported while preventing magnetic flux leakage due to the gap portion. Since the operation can be ensured and the centering portion is provided on the side farther from the clutch than the gap portion, no magnetic flux leaks from the centering portion to the case-shaped torque transmitting member side.

The electromagnetic coupling according to the fifth aspect can provide the same effects as the configurations according to the first to fourth aspects.

The electromagnetic coupling having this configuration is
A large torque transmission capacity is obtained by the boosting function of the cam mechanism, which is optimal for a power transmission device for a vehicle.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment.

FIG. 2 is a characteristic diagram showing a relationship between a gap and torque.

FIG. 3 is a characteristic diagram showing a change in torque with respect to a current when a gap is provided and when no gap is provided.

FIG. 4 is a sectional view showing a second embodiment.

FIG. 5 is a partial sectional view showing a third embodiment.

FIG. 6 is a sectional view showing a conventional example.

[Explanation of symbols]

Reference Signs List 1 electromagnetic coupling 3 rotating case (case-like torque transmitting member) 5 inner shaft (shaft-like torque transmitting member) 7 main clutch (clutch) 9 ball cam (cam mechanism) 15 pilot clutch 19 electromagnet 25 cylindrical member (clutch is disposed Torque transmitting member) 27 Rotor (one side wall in the axial direction constituting a part of the magnetic path) 35 Gap

Claims (5)

[Claims] 1. A torque transmission member comprising: a case-shaped torque transmission member; a shaft-shaped torque transmission member; a clutch connecting the torque transmission member and an electromagnet for intermittently operating the clutch via a magnetic path; An axial side wall forming a part of the road and a torque transmitting member on which a clutch is disposed, and a gap for preventing magnetic flux leakage between the axial side wall and the torque transmitting member. An electromagnetic coupling characterized by being provided. 2. The electromagnetic coupling according to claim 1, wherein the gap is provided at least between the clutch and a clutch-side surface of an electromagnet. 3. The electromagnetic cup according to claim 1, wherein the gap is set in a direction away from the clutch than a surface of the electromagnet on the clutch side. ring. 4. The electromagnetic device according to claim 1, wherein a centering portion of one axial side wall portion is provided on a side farther from the clutch than the gap portion. Type coupling. 5. The invention according to claim 1, further comprising a pilot mechanism and a cam mechanism, wherein the pilot mechanism is operated and stopped by an electromagnet,
When the pilot mechanism operates, torque is applied to the cam mechanism, and the clutch is connected by the generated pressing force.