JP2002340046A - Electromagnetic coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a strong and low-cost material as a torque transmitting member and prevent an increase in size by preventing the leakage of a magnetic flux. SOLUTION: An electromagnetic coupling comprises torque transmitting members 3 and 5, a clutch 7 for coupling them, and an electromagnet 19 for operationally opening and closing the clutch 7 via a magnetic path. The member 3 comprises an axial sidewall part 27 for constituting part of the magnetic path, and the torque transmitting member 25 in which the clutch 7 is disposed. The member 25 has a magnetic force transmission amount reducing means 21 along the magnetic path.

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 Japanese Patent Application Laid-Open No. 10-329562 discloses FIG.
Such a driving force transmission device 501 is described.

[0003] The driving force transmission device 501 includes a rotating case 50.
3, inner shaft 505, main clutch 507,
It comprises a ball cam 509, a pressure plate 511, a cam ring 513, a pilot clutch 515, an armature 517, an electromagnet 519, and the like.

[0004] The driving force transmission device 501 is provided by dividing a propeller shaft on the rear wheel side that is cut off during two-wheel driving in a four-wheel drive vehicle, and a rotating case 503 is connected to a front propeller shaft and an inner shaft. 5
05 is connected to the rear propeller shaft.

When the electromagnet 519 is excited, the armature 5
17 is sucked, and the pilot clutch 515 is pressed and fastened. When the pilot clutch 515 is engaged,
The driving force of the engine is applied to the ball cam 509 due to the generation of pilot torque, and the main clutch 507 is pressed by the generated cam thrust force, so that the driving force transmission device 501
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 519 is stopped,
The pilot clutch 515 is released and the ball cam 50
9, the main thrust force is released, the main clutch 507 is released, the connection of the driving force transmission device 501 is released, the rear wheel side is disconnected, and the vehicle enters a two-wheel drive state.

The rotating case 503 includes a main clutch 50
7 and a rotor 523. The rotor 523 forms a part of the magnetic path of the electromagnet 519, and the cylindrical member 521 is made of stainless steel in order to prevent leakage of magnetic flux from the magnetic path.

[0008]

SUMMARY OF THE INVENTION A driving force transmission device 501 is provided.
With an electromagnetic coupling that opens and closes using an electromagnet, if the magnetic flux leaking from the magnetic path to the outside is large, the required pilot torque cannot be obtained, and the desired driving force cannot be transmitted to the wheels .

Therefore, in the driving force transmission device 501, as described above, the cylindrical member 521 of the rotating case 503 is made of austenitic stainless steel (non-magnetic material) to prevent magnetic flux leakage.

[0010] However, stainless steel is expensive, and the cost is correspondingly high.

Further, austenitic stainless steel is more difficult to cut and form than the alloy steel for shafts, and when used as a material for shafts, it is subjected to nitriding treatment to improve abrasion resistance. Is required, and the cost is further increased.

When the size of the electromagnet 519 is increased in order to compensate for the leakage of the magnetic flux, the current consumption increases and the load on the battery increases, and the device becomes large and heavy, which affects the on-board performance.

When the size of the electromagnet 519 is increased, a controller for controlling the exciting current of the electromagnet 519 also needs to cope with the increase in the current, which further increases the cost.

Therefore, the present invention prevents the leakage of magnetic flux,
The purpose is to provide an electromagnetic coupling that can use a high-strength, low-cost torque transmission member, and that prevents the electromagnet from becoming larger and the resulting device being larger and heavier, which has an effect on vehicle mounting. I have.

[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 opening and closing the clutch via a magnetic path. And a case-shaped torque transmitting member is formed of one axial side wall forming a part of a magnetic path, and a torque transmitting member on which a clutch is disposed. Characterized in that means for reducing the amount of transmission of magnetic force is provided between one side wall portion and another portion.

As described above, the electromagnetic coupling according to the present invention has an external magnetic path in which the magnetic force transmission amount reducing means is provided between one axial side wall of the case-like torque transmitting member and another portion. By controlling the amount of magnetic flux transmitted (leaked) to the magnet in a direction to reduce the amount of magnetic flux leaked from the electromagnet.

Therefore, unlike the conventional example, the case-shaped torque transmitting member does not need to be made of a non-magnetic material, so that a large increase in cost accompanying this can be avoided.

Further, since a material other than a non-magnetic material, for example, a strength material such as steel for machine structural use can be used for the case-shaped torque transmitting member, the cost can be greatly reduced by material costs and processing costs. In addition, it is possible to transmit a sufficient torque.

Further, since the loss of the power supply due to the leakage of the magnetic flux is reduced, in the on-vehicle equipment, the loss of the battery which is the power supply of the electromagnet is reduced, and the controller does not need to be adjusted. can avoid.

According to a second aspect of the present invention, there is provided the electromagnetic coupling according to the first aspect, wherein the magnetic force transmission amount reducing means is a thin portion formed in the torque transmitting member.

The magnetic saturation amount N1 of a magnetic path having a small sectional area S1
Is the magnetic saturation amount N2 of the magnetic path having a larger sectional area S2.
It is known that the magnetic flux is smaller than the above. Therefore, if the cross-sectional area S of the magnetic path is reduced, the magnetic saturation amount N is reduced, and the leakage magnetic flux can be reduced.

Therefore, in the configuration of the second aspect, the cross-sectional area is reduced by forming a thin portion in the torque transmitting member, and the leakage magnetic flux is reduced, thereby obtaining the same operation and effect as the first aspect. .

Further, by using a strength material for the case-shaped torque transmitting member, sufficient strength can be obtained even if a thin portion is formed.

Further, since the case-shaped torque transmitting member can be made to be a sealed type, it is possible to prevent foreign substances from entering, and to seal oil to sufficiently lubricate and cool the inside to improve durability. it can.

In the second aspect, the shape, area,
The residual thickness (depth of the thin portion) may be arbitrarily selected.
Further, these different conditions may be arbitrarily combined.

Further, this combination includes a combination with the through hole according to claim 3.

By doing so, it is possible to finely cope with the desired effect of reducing the leakage magnetic flux and the strength (material and thickness) required for the torque transmitting member.

Further, the thin portion may be formed on the outer circumference or the inner circumference of the torque transmitting member, or may be formed on both the outer circumference and the inner circumference.

If the thin portion is formed on the inner periphery, the thin portion becomes a space for increasing the capacity, the amount of oil to be enclosed increases, and lubrication and lubrication are increased.
The cooling effect is further improved.

According to a third aspect of the present invention, there is provided the electromagnetic coupling according to the first aspect, wherein the magnetic force transmission amount reducing means is a through hole formed in the torque transmitting member.

In this configuration, by forming a through hole in the torque transmitting member, the cross-sectional area is reduced, and the leakage magnetic flux is reduced, so that the same operation and effect as those of the first aspect are obtained.

Further, since the case-shaped torque transmitting member is opened by the through hole, the internal cooling efficiency can be improved.

Further, by using a strength material for the case-shaped torque transmitting member, sufficient strength can be obtained even if a through hole is formed.

In claim 3, the shape and area of the through-hole may be arbitrarily selected, and different conditions may be arbitrarily combined.

Further, this combination includes a combination with the thin portion according to the second aspect.

By doing so, it is possible to finely cope with the desired effect of reducing the leakage magnetic flux and the strength (material, thickness) required for the torque transmitting member.

According to a fourth aspect of the present invention, there is provided the electromagnetic coupling according to the second or third aspect, wherein a plurality of ribs are formed in a circumferential direction at a portion where a thin portion or a through hole is formed. Thus, the same operation and effect as those of the second or third aspect can be obtained.

Further, since the strength required for the case-shaped torque transmitting member is maintained by forming the rib, the strength of the case-shaped torque transmitting member and the effect of reducing the leakage magnetic flux due to the thin portions and the through holes are enhanced. Can be compatible.

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

The electromagnetic coupling having 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 magnetic force of the electromagnet is prevented from being lost by the magnetic force transmission amount reducing means, and the pilot torque required by the pilot mechanism can be obtained, the electromagnetic coupling is
For example, when used in a power transmission system of a vehicle, a desired driving force can be transmitted to wheels according to a change in running conditions of the vehicle, and battery loss is reduced.

Further, since the electromagnet is prevented from becoming large and heavy, the electromagnetic coupling can be mounted on a vehicle more easily.

[0043]

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

The electromagnetic coupling 1 is characterized in that:
The four-wheel drive vehicle is provided between a rear wheel side (rear differential side) and a prime mover side (transfer) side which are separated during two-wheel drive traveling in a four-wheel drive vehicle. Also,
The left and right directions are the left and right directions of the vehicle, and are shown in FIGS.
To the right of the vehicle corresponds to the front of the vehicle (toward the prime mover). 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, thin portion 21 provided on rotating case 3 (magnetic force transmission amount reducing means), It consists of a controller.

The pilot mechanism of the main clutch 7 is constituted by the ball cam 9, the pressure plate 11, the cam ring 13, the pilot clutch 15, the armature 17, the electromagnet 19 and the like.

The rotating 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 a ferromagnetic material (one side wall in the axial direction forming a part of the magnetic path).

The power transmission shaft 23 is formed with a flange portion 29, and the power transmission shaft 23 and the cylindrical member 25 are welded at the flange portion 29. In the flange portion 29, a ring-shaped convex portion 31 is formed concentrically outside the front end portion of the inner shaft 5.

The rotor 27 is screwed to a rear opening of the cylindrical member 25 by a screw portion 33 provided therebetween, and is centered by a fitting portion 35 provided therebetween. A nut 37 is screwed to the screw of the screw portion 33 on the rotor 27 side, and the double nut function applies a thrust force to the cylindrical member 25 and the rotor 27 (the screw portion 33) to prevent loosening, thereby securing the fixing function. Is increasing.

An O-ring 39 is arranged between the cylindrical member 25 and the rotor 27 to prevent oil leakage.

The power transmission shaft 23 projects forward from the differential carrier, and is connected to the transfer side via a companion flange connected to the spline portion 41, a joint, a propeller shaft and the like. 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 its front end is supported by the projection 31 of the power transmission shaft 23 via a ball bearing 43 and is centered.

The front end of the inner shaft 5 is axially positioned with respect to the rotating case 3 (the power transmission shaft 23) via ball bearings 43 by snap rings 45 and 47.

The rear end of the inner shaft 5 is supported on the inner periphery of the rotor 27 via a needle bearing 49, and is axially positioned with respect to the rotor 27 via the needle bearing 49 by a snap ring 51. .

As described above, the front end of the inner shaft 5 is centered by the ball bearing 43 and the rear end of the inner shaft 5 is centered by the needle bearing 49. The vibration of the electromagnetic coupling 1 due to the deflection of the inner shaft 5 is prevented.

Further, between the inner shaft 5 and the rotor 27, a cross section X
An X-ring 53, which is a letter-shaped seal, is arranged to prevent oil leakage.

A drive pinion shaft is connected to a spline portion 55 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 rotary case 3 is hermetically sealed by the O-ring 39 and the X-ring 53, and has an oil hole 5 formed in the flange 29 of the power transmission shaft 23.
Oil is injected from 7. After oil is injected, the oil hole 57 is sealed by press-fitting a steel ball 59.

The hollow inner shaft 5 is defined by a wall 61, and a capacity increasing space 63 for increasing the amount of oil to be filled is formed. Further, the flange portion 29 of the power transmission shaft 23 is provided with capacity increasing spaces 65 and 67 for increasing the amount of oil enclosed. In the capacity increasing spaces 63, 65, and 67, similarly to other portions inside the rotating case 3, the injected oil and air are stored. Further, the capacity increasing space 63 communicates with the main clutch 7 through four radial flow paths 69 formed in the inner shaft 5.

The main clutch 7 is arranged between the rotating case 3 (cylindrical member 25) and the inner shaft 5, and its outer plate 71 is connected to a spline portion 73 formed on the inner periphery of the cylindrical member 25. The inner plate 75 is connected to a spline 77 formed on the outer periphery of the inner shaft 5. In addition, a spacer 79 is disposed in front of the main clutch 7, and a spline portion 7 is provided.
3 is connected.

These inner plates 75 are
It is a paper clutch plate in which a friction material of paper is stuck on both sides of a plate made of an iron-based alloy, and a cylindrical member 2
The magnetic flux is blocked between the inner shaft 5 and the outer shaft 5 (outer plate 71).

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

The inner circumference of the pressure plate 11 is connected to the spline portion 77 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 79.

The cam ring 13 is disposed on the outer periphery of the inner shaft 5 so as to be relatively rotatable.
A thrust bearing 81 and a washer 83 that receive a cam reaction force of the ball cam 9 are disposed between the thrust bearing 81 and the rotor 27.

The pilot clutch 15 is
The outer plate 85 is connected to the spline portion 73 of the cylindrical member 25, and the inner plate 87 is connected to a spline portion 89 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 73 of the cylindrical member 25.

The core 91 of the electromagnet 19 penetrates through an appropriate air gap into a ring-shaped recess 93 formed in the rotor 27 and is supported on the rotor 27 by a double-sided seal type ball bearing 95. .

The leg portion 101 of the dust cover 99 is engaged with the groove 97 provided in the core 91. The dust cover 99 is connected to the differential carrier side and keeps the electromagnet 19 (core 91) from rotating.

The lead wire 103 of the electromagnet 19 is wired along the inside of the dust cover 99 and the grommet 10
5 and is drawn out of the differential carrier and connected to a vehicle-mounted battery.

The magnetic path of the electromagnet 19 is constituted by the rotor 27, the pilot clutch 15 and the armature 17.

The rotor 27 is divided into a radially outer side and an inner side by a non-magnetic stainless steel ring 107. Also, each plate 8 of the pilot clutch 15
5, 87 at the radial position corresponding to the ring 107,
A plurality of notches 109, and these notches 109
Are provided in the circumferential direction. The ring 107 and the notch 109 prevent short-circuit of magnetic flux 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 111 is formed in the above-described 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 a 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 the generated cam thrust force is received. 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 the power transmission system such as the drive pinion shaft, and the rear differential rotates from the rear differential. 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, if 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.

The thin portion 21 is formed on the outer periphery of the cylindrical member 25 (rotating case 3). As shown in FIG.
Reference numeral 1 denotes a rectangle that is long in the circumferential direction, and is disposed at a plurality of locations at equal intervals in the circumferential direction.

Further, ribs 113 are formed between the thin portions 21 so that the strength required for torque transmission can be increased by the cylindrical member 2.
5 given.

As shown in FIG. 1, each thin portion 21 is arranged along a magnetic flux loop 111 (magnetic path of the electromagnet 19).
Each thin portion 21 and rib 113 serve as a magnetic path of the leakage magnetic flux,
In a portion where the cross-sectional area is reduced to a fraction by providing the thin portion 21, the amount of magnetic flux leaking from the magnetic flux loop 111 to the cylindrical member 25 side is greatly reduced due to the decrease in magnetic saturation as described above. .

In addition to the effect of reducing the leakage magnetic flux by each of the thin portions 21, as described above,
The use of a paper clutch plate for 5 prevents leakage of magnetic flux between the cylindrical member 25 and the inner shaft 5.

Incidentally, even if a ball bearing 43 having no magnetic flux interruption function is arranged between the front end of the inner shaft 5 and the rotating case 3 (recess 31), this portion is a magnetic path of the electromagnet 19 (magnetic flux loop 111). Far away from
The leakage 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, a necessary pilot torque is obtained by the pilot clutch 15, and the pilot torque is transmitted to the rear wheel via the electromagnetic coupling 1. Thus, it is possible to transmit a desired driving force according to a change in the running conditions of the vehicle.

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 circumference of the main clutch 7, ball cam 9, pilot clutch 15, spline portions 73, 77, 89, thrust bearing 81, washer 83, cam ring 13. And the X-ring 53 and the like, which are sufficiently lubricated and cooled.

The oil in the capacity increasing space 63 flows into the main clutch 7 by centrifugal force from the radial flow path 69 of the inner shaft 5 and is given to the sliding surface between the outer plate 71 and the inner plate 75. The lubrication and cooling effects are further improved.

An oil hole 115 is formed in each inner plate 75 of the main clutch 9 to promote the movement of oil to the sliding surfaces of the plates 71 and 75, and to improve the lubrication and cooling effects thereof. ing.

Further, a through hole 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 serves as an oil flow passage, and serves as a ball cam 9. ,
Promotes the movement of oil to the pilot clutch 15 side,
These lubrication and cooling effects are improved.

Thus, the electromagnetic coupling 1 is configured.

The electromagnetic coupling 1 is, as described above,
By forming the thin portion 21 in the cylindrical member 25, the leakage magnetic flux of the electromagnet 19 is greatly reduced in a region where the leakage of the magnetic flux along the magnetic flux loop 111 is most likely to occur.

Therefore, unlike the conventional example, the cylindrical member 25 does not need to be made of a non-magnetic material, and a large increase in cost due to this is avoided.

Further, since a strong material such as steel for machine structural use can be used for the cylindrical member 25, the cost can be greatly reduced in terms of material cost and processing cost, and sufficient driving force can be applied to the rear wheel. Can be transmitted.

Further, since a strength material is used for the cylindrical member 25, sufficient strength can be obtained even if the thin portion 21 is formed.

Further, the loss of the battery due to the leakage of the magnetic flux is reduced, and the adjustment of the controller becomes unnecessary.
The cost increase accompanying this is avoided.

Further, the means for reducing the amount of transmission of magnetic force is
As described above, since the rotating case 3 can be sealed as described above, foreign matters can be prevented from entering, and the inside can be sufficiently lubricated and cooled with oil, thereby improving durability.

Further, the depth (remaining thickness), shape, area, etc. of the thin portion 21 may be arbitrarily selected, or different conditions may be arbitrarily combined.

By doing so, the function of reducing the leakage magnetic flux and the strength (material, thickness) required for the cylindrical member 25 can be finely dealt with.

Further, the provision of the rib 113 achieves both the strength required for the cylindrical member 25 and the effect of reducing the leakage magnetic flux.

Further, 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 power transmission device for a vehicle.

The thin portion 21 may be formed on the inner circumference of the cylindrical member 25, or may be formed on both the outer circumference and the inner circumference.

If the thin portion 21 is formed on the inner periphery, the space becomes a space for increasing the capacity, the amount of oil enclosed increases, and the lubrication and cooling effects are further improved.

[Second Embodiment] FIG. 3 shows an electromagnetic coupling 201 (a second embodiment of the present invention).

The electromagnetic coupling 201 is the same as the electromagnetic coupling 1 of the first embodiment except that the thin portion 21 is formed as a through hole 203.
It has the following features.

In the electromagnetic coupling 201, the through hole 2
The cross-sectional area of the portion where the thin portion 30 is formed is smaller than the cross-sectional area of the portion where the thin portion 21 is formed, and the amount of magnetic saturation is reduced. Therefore, the effect of reducing the leakage magnetic flux is further reduced.

The electromagnetic coupling 201 thus configured has the same effects as the electromagnetic coupling 1 except for the effect that the electromagnetic coupling 1 (first embodiment) is a sealed type. .

Further, since the rotating case 3 is opened by providing the through holes 203, the internal cooling efficiency is improved.

Further, since a strength material is used for the cylindrical member 25, sufficient strength can be obtained even if the through holes 203 are formed.

The shape and area of the through-hole 203 may be arbitrarily selected, or different conditions may be arbitrarily combined.

By doing so, the function of reducing the leakage magnetic flux and the strength (material, thickness) required for the cylindrical member 25 can be finely dealt with.

Also, by providing the rib 113,
The strength required for the cylindrical member 25 and the effect of reducing the leakage magnetic flux are compatible.

In the present invention, the shape of the thin portion and the through-hole is not limited as well as the depth and the area, and any shape can be selected as needed.

FIGS. 4, 5 and 6 show examples of the shapes of various thin portions and through holes provided in the cylindrical member 25. FIG.

FIG. 4 shows an example of a diamond 301 and a diamond 30.
A triangle 303 obtained by equally dividing 1 is arranged in the circumferential direction, and a rib 305 is formed therebetween.

The diamond 301 and the triangle 303 may be thin portions or through holes, or a combination of one thin portion and the other through hole.

Further, a thin portion and a through hole may be combined in each of the diamond 301 and the triangle 303.

The thin portions of the diamond 301 and the triangle 303 and the through-holes reduce the cross-sectional area of the cylindrical member 25, reduce the leakage magnetic flux, and keep the strength of the cylindrical member 25 high by the rib 305.

In the example of FIG. 5, the triangles 303 are alternately arranged in the circumferential direction, and the ribs 307 are formed therebetween.

The triangle 303 may be a thin portion or a through hole, or a combination of the thin portion and the through hole.

The cross-sectional area of the cylindrical member 25 is reduced by the thin portion of the triangle 303 and the through-hole, and the leakage of magnetic flux is reduced, and the strength of the cylindrical member 25 is kept high by the rib 307.

In the example shown in FIG. 6, a circle 309 is arranged in the circumferential direction, and a rib 311 is formed between them.

The circle 309 may be a thin portion or a through hole, or a combination of the thin portion and the through hole.

The cross-sectional area of the cylindrical member 25 is reduced by the thin portion of the circular 309 and the through hole, and the leakage of magnetic flux is reduced, and the strength of the cylindrical member 25 is kept high by the ribs 311.

In any of the examples, the effect of reducing the leakage magnetic flux, the effect of the cylindrical member 25, and the thickness of the cylindrical member 25 depend on whether each of the shapes is a thin portion or a through hole or a combination thereof.
Can be finely adapted to the strength (material, wall thickness), etc. required for

When each shape is made to be a thin portion, the depth (remaining thickness) is changed to reduce the desired leakage magnetic flux, the strength (material, thickness) required for the cylindrical member 25, and the like. Can be handled in detail.

In each embodiment, the main clutch 7 is a mechanism for transmitting a driving force between the case-shaped torque transmitting member (rotating case 3) and the shaft-shaped torque transmitting member (inner shaft 5). , Outer plate 71
The inner case 75 and the inner plate 75 alone have no meaning. The rotating case 3, the inner shaft 5, the outer plate 71, and the inner plate 75 are all essential components of the main clutch 7.

For the same reason, the rotating clutch 3, the cam ring 13, the outer plate 85, and the inner plate 87 are essential components of the pilot clutch 15.

The ball cam 9 (cam mechanism) is a mechanism for converting the transmitted driving torque into a pressing force of the main clutch 7, and includes a pressure plate 11, a cam ring 13, a cam surface formed on these, The pressure plate 1 as well as the ball placed between
The essential components include an inner shaft 5 for transmitting the driving force to the motor 1, a rotating case 3 for transmitting the driving force to the cam ring 13, and a pilot clutch 15.

The pilot mechanism constituting the electromagnetic coupling according to the present invention is not limited to a pilot clutch mechanism using a friction clutch such as a multi-plate clutch, a single-plate clutch, and a cone clutch, but also without using a clutch. A known pilot mechanism that performs a pilot function with an electromagnet may be used.

The main clutch and the pilot clutch may be any type of clutch other than the multi-plate clutch as long as it is a friction clutch such as a single-plate clutch or a cone clutch. These may be wet or dry.

The coupling of the present invention can be used for a differential limiting mechanism by being arranged between differential rotating members of a differential device.

[0132]

According to the electromagnetic coupling of the present invention, the leakage magnetic flux of the electromagnet is controlled and reduced by the magnetic force transmission amount reducing means, so that the case-shaped torque transmitting member does not need to be made of a non-magnetic material. A significant increase in costs associated with this is avoided.

Further, by using a strong material such as steel for machine structural use as the case-shaped torque transmitting member, it is possible to significantly reduce costs in terms of material costs and processing costs, and to transmit a sufficient torque. .

In the on-vehicle equipment, the battery loss is reduced, and the controller does not need to be adjusted, thereby avoiding an increase in cost.

According to the electromagnetic coupling of the second aspect, an effect equivalent to that of the first aspect can be obtained by forming a thin portion in the magnetic flux leakage area to reduce the amount of magnetic saturation.

Further, by using a strength material for the case-shaped torque transmitting member, sufficient strength can be obtained even if a thin portion is formed.

Further, since the case-shaped torque transmitting member can be made a sealed type, intrusion of foreign matter can be prevented, and oil can be sealed to sufficiently lubricate and cool the inside, thereby improving durability.

According to the electromagnetic coupling of the third aspect, the same effect as that of the first aspect can be obtained by reducing the amount of magnetic saturation by forming a through hole in the leakage area of the magnetic flux.

In addition, the case-shaped torque transmitting member is opened by the through hole, and the internal cooling efficiency is improved.

Further, by using a strength material for the case-shaped torque transmitting member, sufficient strength can be obtained even if a through hole is formed.

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

Further, since the strength of the case-shaped torque transmitting member is kept high by the ribs, both the strength and the effect of reducing the leakage magnetic flux are compatible.

According to the electromagnetic coupling of the fifth aspect, the same effects as those of the first to fourth aspects can be obtained.

In addition, the electromagnetic coupling having this configuration is as follows.
Since a large torque transmission capacity can be obtained by the boosting function of the cam mechanism, it is most suitable for a power transmission device for a vehicle, and can transmit a desired driving force to wheels according to a change in running conditions, and can reduce a battery power. Loss is reduced.

In addition, the size and weight of the electromagnet can be prevented, and the mountability of the electromagnet can be improved.

[Brief description of the drawings]

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

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a partial sectional view showing a second embodiment.

FIG. 4 is a view showing another example of a thin portion or a through hole provided in a cylindrical member.

FIG. 5 is a drawing showing another example of a thin portion or a through hole provided in a cylindrical member.

FIG. 6 is a drawing showing another example of a thin portion or a through hole provided in a cylindrical member.

FIG. 7 is a sectional view of 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: pilot mechanism) 15 pilot clutch (pilot mechanism) 19 electromagnet ( Pilot mechanism) 21 Thin part (means for reducing transmission of magnetic force) 25 Cylindrical member (torque transmitting member on which clutch is disposed) 27 Rotor (one side wall in the axial direction forming a part of magnetic path) 113 Rib 201 Electromagnetic type Coupling 203 Through-hole (transmission means for reducing magnetic force) 301 Rhombic thin part or through-hole (means for reducing transmission of magnetic force) 303 Triangular thin part or through-hole (means for reducing transmission of magnetic force) 305, 307, 311 Rib 309 Circular thin portion or through hole (magnetic force transmission amount reducing means)

Claims (5)

[Claims] 1. A case-like torque transmitting member, a shaft-like torque transmitting member, a clutch connecting these, and an electromagnet for opening and closing the clutch via a magnetic path, wherein the case-like torque transmitting member is An axial one-side wall part forming a part of the road and a torque transmitting member on which a clutch is disposed, and a magnetic force is applied between the one axial side wall part and another part along the magnetic path. An electromagnetic coupling provided with transmission amount reducing means. 2. The electromagnetic coupling according to claim 1, wherein the magnetic force transmission amount reducing means is a thin portion formed on the torque transmitting member. 3. The electromagnetic coupling according to claim 1, wherein the magnetic force transmission amount reducing means is a through hole formed in the torque transmitting member. 4. The invention according to claim 2 or 3, wherein the thin portion or the portion where the through-hole is formed,
An electromagnetic coupling in which ribs are formed at a plurality of positions in a circumferential direction. 5. The invention according to claim 1, further comprising: a pilot mechanism operated and stopped by an electromagnet; and a cam mechanism, wherein when the pilot mechanism operates, torque is applied to the cam mechanism. An electromagnetic coupling in which a clutch is connected by a pressing force generated.