JP2003146100A - Electromagnetic coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust a characteristic of current (I)-transmission torque (T) at a low cost and reduce drag torque greatly. SOLUTION: An electromagnetic coupling is provided with torque transmission members 3, 5, a friction clutch 7 arranged between the members 3 and 5, a pressing member 11 of the clutch 7, and an operation means composed of an electromagnet 19 and an energizing member 23 for giving operation force in the opposite directions for each other to the member 11 and moving and operating the member 11 by the action of the electromagnet 19 to tighten the clutch 7. A connection means 21 for connecting the members 5 and 11 mutually in the axial direction is provided, and a counterforce providing means 23 for pushing the member 11 back in the direction of connection release of the clutch 7 by a counterforce having the predetermined strength through the member 5 and the connection means 21 is provided.

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 in a power transmission system of a vehicle, for example.

[0002]

2. Description of the Related Art FIG. 6 is disclosed in Japanese Patent Laid-Open No. 10-329562.
Such a driving force transmission device 501 is described.

The driving force transmission device 501 includes a rotating case 503, an inner shaft 505, and a main clutch 50.
7, ball cam 509, pressure plate 511,
The cam ring 513, the pilot clutch 515, the armature 517, the electromagnet 519 and the like are included.

In a four-wheel drive vehicle, the driving force transmission device 501 is arranged by dividing the propeller shaft on the rear wheel side, which is separated during traveling on two-wheel drive, and the rotating case 503 is connected to the propeller shaft on the front side. The shaft 505 is connected to the rear propeller shaft.

When the electromagnet 519 is excited, the armature 5
17 is attracted and the pilot clutch 515 is pressed and fastened. When the pilot clutch 515 is engaged,
Pilot torque is generated and the driving force of the engine is applied to the ball cam 509, the generated cam thrust force presses the main clutch 507, and the driving force transmission device 501
Are connected and the driving force is transmitted to the rear wheels, so that the vehicle is in 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 is released.
The cam thrust force of No. 9 disappears, the main clutch 507 is released, the drive force transmission device 501 is disconnected, the rear wheel side is disconnected, and the vehicle enters the two-wheel drive state.

The rotating case 503 has a main clutch 50.
It is composed of a cylindrical member 521 to which 7 is connected and a rotor 523. The rotor 523 constitutes a part of the magnetic path of the electromagnet 519, and the cylindrical member 521 is made of stainless steel to prevent leakage of magnetic flux from the magnetic path.

The driving force transmission device 501 is hermetically sealed,
Oil is sealed inside and the pilot clutch 5
15, the main clutch 507, the ball cam 509, etc. are lubricated and cooled.

[0009]

A driving force transmission device 501.
As described above, in the electromagnetic coupling used in the power transmission system of the vehicle, for example, the exciting current (I) of the electromagnet and the transmission torque generated at that time are determined according to the type of vehicle to be mounted and the magnitude of the transmission torque to be handled. It may be desired to adjust the characteristic (current-torque characteristic) with (T).

However, not only the driving force transmission device 501,
The conventional electromagnetic coupling does not have a function of adjusting the current-torque characteristic, and the vehicle type applicable to one model is limited to a narrow range.

To adjust the current-torque characteristic,
The effective diameters of the pilot clutch 515 and the main clutch 507, the number of plates, the cam angle of the ball cam 509, the attraction force of the electromagnet 519, and the like must be changed, and the cost for adjusting the characteristics is extremely high.

Further, since the driving force transmission device 501 is constructed so as to enclose oil to lubricate the inside, as in a general electromagnetic coupling, the pilot clutch 515 and the main clutch due to the viscosity of the oil. It is unavoidable that drag torque (drag torque) is generated at 507. This drag torque is applied to the pilot clutch 515.
And the main clutch 507, the drag torque of the pilot clutch 515 is amplified by the ball cam 509 and presses the main clutch 507, so that the influence is great.

Therefore, even if an attempt is made to switch the vehicle from the four-wheel drive state to the two-wheel drive state, since the connecting torque remains in the driving force transmission device 501 due to such drag torque, the complete two-wheel drive state is set. Is impossible,
It is difficult to improve fuel efficiency and turning performance.

Therefore, according to the present invention, the friction clutch is operated by the electromagnet, and the characteristics of the exciting current (I) of the electromagnet and the transmission torque (T) of the friction clutch can be easily changed at low cost. At the same time, it aims to provide an electromagnetic coupling in which drag torque of the friction clutch is significantly reduced.

[0015]

An electromagnetic coupling according to a first aspect of the present invention comprises a pair of torque transmission members, a friction clutch arranged between the pair of torque transmission members, and a pressing member of the friction clutch. An electromagnetic coupling including an electromagnet and an urging member that apply an operating force to the pressing member in opposite directions, and an operating means for moving the pressing member to open and close the friction clutch by operating or stopping the operation of the electromagnet. A connecting means for axially connecting one of the pair of torque transmitting members and the pressing member is provided, and the pressing member is connected to the pressing member with a predetermined strength via the one torque transmitting member and the connecting means. It is characterized in that a counter force applying means for pushing back the friction clutch in the disengagement direction of the friction clutch is provided.

The operation means of the friction clutch is composed of an electromagnet for applying an operation force in the opposite direction to the pressing member and an urging member (for example, a spring).

When the friction clutch is engaged with the electromagnet and the operation of the electromagnet is stopped, a spring (return spring)
In the configuration in which the engagement of the friction clutch is released by, the magnitude of the transmission torque is directly controlled by the exciting current (I) of the electromagnet.

Further, when the friction clutch is engaged with the spring and the electromagnet is operated, the engagement of the friction clutch is released against the urging force of the spring, so that the stronger the urging force of the spring is, the more exciting current (I ) Is required to be increased, similarly, the magnitude of the transmission torque is controlled by the exciting current (I) of the electromagnet.

Therefore, in the electromagnetic coupling of the present invention which is provided with the counter force applying means for pushing back the pressing member in the disengagement direction of the friction clutch, the counter force applying means is replaced with a different one. For example, the exciting current (I) of the electromagnet is changed according to the type of vehicle to be installed and the magnitude of the transmission torque to be handled.
It becomes possible to adjust the characteristics (current-torque characteristics) between the transmission torque (T) and the transmission torque (T), and it is possible to widely apply one model to different vehicle types.

In addition, the electromagnetic coupling of the present invention, in which the current-torque characteristic can be adjusted only by providing the counter force applying means in this way, is the main clutch 507 and the pilot clutch 51 in order to adjust the characteristics.
5, the cost for adjusting the characteristics is significantly reduced as compared with the conventional example in which the ball cam 509, the electromagnet 519, and the like need to be changed.

Further, the counter force works in the direction of canceling the drag torque generated in the friction clutch, and the drag torque canceling function by the counter force has the effect of increasing the viscosity of the oil and increasing the drag torque during the cold season or the oil temperature. It is especially effective when it is not fully raised.

Therefore, for example, when the electromagnetic coupling of the present invention is used in a power transmission system on the side of a wheel that is disconnected in a two-wheel drive state in a four-wheel drive vehicle, the residual torque of the friction clutch is released when the connection is released. Since this is prevented, the vehicle is brought into a complete two-wheel drive state, the response for switching to the two-wheel drive state is quickened, and fuel efficiency and turning performance can be sufficiently improved.

The invention according to claim 2 is the electromagnetic coupling according to claim 1, characterized in that the counter force applying means is a spring, and an operation equivalent to that of the construction of claim 1 The effect can be obtained.

Further, in the electromagnetic coupling of the present invention which pushes back the pressing member via the one torque transmitting member, the counter force imparting means can be arranged at the end portion of the one torque transmitting member. In this configuration in which the spring is used as the means, the end portion of the one torque transmission member can be used as the seat surface of the spring.

With such a structure, it is not necessary to specially process the seat surface of the spring, and the cost can be reduced accordingly.

Further, in the structure in which the spring is arranged at the end of the torque transmission member, the spring can be easily assembled.

The invention of claim 3 is the electromagnetic coupling according to claim 2, characterized in that a screw mechanism for adjusting the amount of flexure of the spring is provided, and is equivalent to the configuration of claim 2. The action and effect of can be obtained.

Further, in this structure, by adjusting the bending amount of the spring by the screw mechanism, the current-torque characteristic can be adjusted at a further reduced cost without replacing the spring.

Further, since the current-torque characteristic (the amount of flexure of the spring) can be finely adjusted by the screw mechanism, it becomes possible to finely respond to the difference in the requirements which differ for each vehicle type, and the number of applicable vehicle types further increases. To do.

The invention according to claim 4 is the electromagnetic coupling according to claim 3, characterized in that the screw mechanism can be operated from the outside by exposing the screw mechanism to the outside. It is possible to obtain the same operation and effect as the configuration of claim 3.

Further, in this construction in which the screw mechanism can be operated from the outside, it is not necessary to disassemble the electromagnetic coupling in adjusting the current-torque characteristics, so that the characteristics can be adjusted extremely easily and the adjustment cost can be reduced. Significantly reduced.

A fifth aspect of the present invention is the electromagnetic coupling according to any one of the first to fourth aspects, wherein both the torque transmission members are sealed by seals and oil is enclosed, and the connection is made. One of the torque transmission members connected to the pressing member by means is provided with a pressure receiving surface that receives the pressure of the enclosed oil and pushes back the pressing member in the disengagement direction of the friction clutch, and the counter force applying means, The pressure-receiving surface is the pressure-receiving surface.
It is possible to obtain the same actions and effects as the configurations of 4 to 4.

In the sealed electromagnetic coupling in which oil is sealed, the pressure receiving surface of the torque transmitting member serves as a counter force applying means, and the oil pressure applied to the pressure receiving surface causes the pressing member to disengage the friction clutch. It is pushed back and the drag torque is canceled.

Further, as the oil temperature rises, the oil pressure applied to the pressure receiving surface rises, and the drag torque canceling function is enhanced.

When the oil is at a low temperature, for example, a biasing force (counterforce) such as a spring pushes back the pressing member, and when the temperature of the oil rises, the oil pressure (counterforce) applied to the pressure receiving surface acts on the pressing member. Since it pushes back, in the structure of claim 5, a sufficient drag torque canceling function can be obtained in a wide oil temperature range from low temperature to high temperature.

A sixth aspect of the present invention is the electromagnetic coupling according to any one of the first to fifth aspects, wherein the pilot mechanism is operated and stopped by an operating means.
A cam mechanism is provided, and when the pilot mechanism is actuated, the torque transmitted between the torque transmitting members is applied to the cam mechanism, and the friction clutch is connected by the generated pressing force. It is possible to obtain the same operation and effect as the configuration.

Further, in the case where the pilot mechanism is constituted by using the clutch, even if the cam mechanism is actuated by the drag torque of the pilot clutch and the pressing member is pressed toward the friction clutch side, the counter force of the counter force imparting means is kept. Since the pressing member is pushed back, the residual torque of the friction clutch (main clutch) is prevented.

Therefore, when it is used in a power transmission system on the side of a wheel that is separated into a two-wheel drive state in a four-wheel drive vehicle as described above, residual torque when the connection is released is prevented and the vehicle becomes a complete two-wheel drive. The wheel drive state is achieved, and fuel efficiency and turning performance can be sufficiently improved.

[0039]

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. 1, 4, and 5.

The electromagnetic coupling 1 has the features of claim 1,
It has the characteristics of 5 and 6, and is arranged in the power transmission system on the rear wheel side, which is disconnected during two-wheel drive traveling in a four-wheel drive vehicle. Further, the left and right directions are the left and right directions of this vehicle, and the right side of FIG. 1 corresponds to the front side (motor side) of this vehicle. It should be noted that members and the like to which reference numerals are not given 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 housed in the differential carrier.

The electromagnetic coupling 1 includes a rotating case 3
(Other torque transmitting member), hollow inner shaft 5
(One torque transmission member), multi-plate type main clutch 7
(Friction clutch), ball cam 9 (cam mechanism), pressure plate 11 (pressing member), cam ring 13, multi-plate pilot clutch 15, armature 17, electromagnet 19 (operating means), connecting means 21 (torque transmitting member and pressing member). Connection means), a return spring 23 (spring: an urging member that gives an operating force in the opposite direction to the electromagnet: an operating means: a counter force applying means), pressure receiving surfaces 25 and 27 (counter force applying means), a controller and the like. Has been done.

The electromagnet 19 and the return spring 2
The operation means of the pressure plate 11 is constituted by 3, and the ball cam 9 and the pressure plate 1
1, the cam ring 13, the pilot clutch 15, the armature 17, the electromagnet 19 and the like constitute a pilot mechanism.

The rotating case 3 is composed of a power transmission shaft 29 and a cylindrical member 31, each of which is made of a strength material such as steel for machine structural use, a rotor 33 made of a ferromagnetic material, and the like.

Flange portions 35 and 37 are formed on the power transmission shaft 29 and the cylindrical member 31, respectively, and the power transmission shaft 29 and the cylindrical member 31 are welded at these flange portions 35 and 37. In addition, the power transmission shaft 29 is formed with a concentric projection 39 that penetrates the inner circumference of the front end of the inner shaft 5.

A ring 41 made of a non-magnetic material is screwed into a rear side opening of the cylindrical member 31 by a screw portion 43 provided between them, and the rotor 33 is provided with a screw portion 44 provided between them. Is screwed onto the inner circumference of the ring 41. Further, the cylindrical member 31 and the ring 41 are radially centered by a fitting portion 45 provided between them, and the ring 41 and the rotor 33 are radially centered by a fitting portion 46 provided between them. It is ringed.

The fitting portions 45 and 46 prevent oil from leaking by their respective sealing functions.

The ring 41 is arranged along the magnetic path of the electromagnet 19 between the cylindrical member 31 that allows the magnetic flux to pass therethrough and the rotor 33 made of a magnetic material to prevent leakage of the magnetic flux.

Further, a nut 47 is screwed to the screw thread on the rotor 33 side of the screw portion 44. The nut 47 presses the rear end of the ring 41, and its double nut function applies thrust force to the threaded portion 44 to prevent loosening and enhances the fixing function.

The power transmission shaft 29 projects forward from the differential carrier and is connected to the transfer side via a companion flange connected to the spline portion 49, 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 rotating case 3 from the rear, and the front end of the hollow hole 51 is supported by the convex portion 39 of the power transmission shaft 29 and centered.

The rear end of the inner shaft 5 is supported on the inner circumference of the rotor 33 via a needle bearing 53. The needle bearing 53 is axially positioned on the rotor 33 by the snap ring 55, but the inner shaft 5 can move in the axial direction within an appropriate range by sliding with the needle bearing 53.

In this way, the inner shaft 5 has the convex portion 3
Since the front end portion is centered by 9 and the rear end portion is centered by the needle bearing 53, the inner shaft 5 is centered by these centering functions.
And the vibration of the electromagnetic coupling 1 due to the vibration of the inner shaft 5 are prevented.

Inside the rotating case 3, there is a power transmission shaft 29.
The oil is injected from the oil hole formed in the flange portion 35 of the above, and after the oil is injected, the oil hole is sealed by press-fitting a steel ball.

Between the inner shaft 5 and the rotor 33, inside the needle bearing 53, the cross section is X-shaped.
An X ring 57, which is a letter-shaped seal, is arranged to prevent oil leakage.

The rotating case 3 is sealed by the X ring 57 and the fitting portions 45, 46.

A drive pinion shaft is connected to a spline portion 59 formed on the inner circumference of the inner shaft 5. A drive pinion gear is integrally formed on 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 through these power transmission systems.

The hollow hole 51 of the inner shaft 5 is partitioned by a lid member 61, and a capacity increasing space 63 for increasing the amount of oil filled is formed. The injected oil and air are accommodated in the capacity-increasing space 63 as in the other parts inside the rotating case 3. Further, the capacity increasing space portion 63 communicates with the main clutch 7 side by a radial oil passage 65 formed in the inner shaft 5.

The main clutch 7 is arranged between the rotating case 3 (cylindrical member 31) and the inner shaft 5, and its outer plate 67 is connected to a spline portion 69 formed on the inner circumference of the cylindrical member 31. The inner plate 71 is connected to a spline portion 73 formed on the outer circumference of the inner shaft 5.

A spacer 75 is arranged in front of the main clutch 7, is connected to the spline portion 69, and is centered on the outer periphery of the flange portion 35 of the power transmission shaft 29.

Further, these inner plates 71 are
A paper clutch plate in which friction materials of paper are pasted on both sides of a plate made of an iron-based alloy.
The magnetic flux is blocked between 1 (outer plate 67) and the inner shaft 5.

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

The inner circumference of the pressure plate 11 is connected to the spline portion 73 of the inner shaft 5,
The main clutch 7 receives the thrust force of the ball cam 9.
Is pressed against the rotating case 3 via the spacer 75 to be fastened.

The cam ring 13 is arranged on the outer circumference of the inner shaft 5 so as to be rotatable relative to the inner shaft 5.
A thrust bearing 77 and a washer 79 that receive the cam reaction force of the ball cam 9 are disposed between the rotor 33 and the rotor 33.

The pilot clutch 15 includes the rotating case 3
The outer plate 81 is arranged between the (cylindrical member 31) and the cam ring 13, and the outer plate 81 is connected to the spline portion 69 of the cylindrical member 31, and the inner plate 83 is connected to the spline portion 85 formed on the outer circumference of the cam ring 13. Has been done.

The armature 17 is arranged between the pressure plate 11 and the pilot clutch 15, and its outer periphery is movably connected to the spline portion 69 of the cylindrical member 31.

The core 87 of the electromagnet 19 penetrates into a ring-shaped recess 89 formed in the rotor 33 via an appropriate air gap, and is supported on the rotor 33 by ball bearings 91 of both sides seal type. .

Further, the leg portion 97 of the dust cover 95 is engaged with the groove 93 provided in the core 87. The dust cover 95 is connected to the differential carrier side and prevents the electromagnet 19 (core 87) from rotating.

The lead wire 99 of the electromagnet 19 is wired along the inside of the dust cover 95, and the grommet 101
Through the differential carrier and is connected to a vehicle battery.

The core 87, the rotor 33, the pilot clutch 15, and the armature 17 constitute a magnetic path of the electromagnet 19.

The rotor 33 is divided into a radially outer side and an inner side by a stainless steel ring 103 which is a non-magnetic material. Also, each plate 8 of the pilot clutch 15
1,83 at radial positions corresponding to the ring 103,
A plurality of cutouts 105 and a bridge portion connecting the cutouts 105 are provided in the circumferential direction. The ring 103 and the notch 105 prevent short circuit of magnetic flux on the magnetic path.

The connecting means 21 is composed of a circlip 109 attached to the spline portion 73 of the inner shaft 5. The circlip 109 faces the front surface of the pressure plate 11, and when the inner shaft 5 moves backward, the pressure plate 11 is also moved backward via the circlip 109.

A washer 1 is provided at the front end of the inner shaft 5.
11 are arranged.

The return spring 23 (disc spring) is disposed between the flange portion 35 of the power transmission shaft 29 and the washer 111 in a bent state, and the counter force (biasing force) causes the return spring 23 and the inner shaft 5 to move. The pressure plate 11 is pushed back in the backward direction (disengagement direction of the main clutch 7) via the connecting means 21.

The front end (washer 111) of the inner shaft 5 and the flange portion 35 are formed by the return spring 23.
It is used for each seat surface.

A graph 151 in FIG. 4 shows the load-deflection characteristic of the return spring 23. The return spring 23 is used within a range 153 where the counter force (load) and the deflection are proportional.

The pressure receiving surface 25 is formed on the front surface of the lid member 61 mounted in the hollow hole 51 of the inner shaft 5, and the pressure receiving surface 27 is formed on the front end portion of the inner shaft 5 on which the washer 111 is arranged. ing.

In the electromagnetic coupling 1 in which the oil is sealed as described above, the internal pressure rises as the temperature rises, but the main clutch 7, the pilot clutch 15, and the pressure plate 11 disposed inside the electromagnetic coupling 1. In each member such as, the oil pressures received from the entire surface cancel each other out. However, the pressure receiving surface 2 that does not have a surface for canceling the oil pressure
Upon receiving this oil pressure, a counter force is generated in the valves 5 and 27, and the pressure plate 11 is pushed back in the backward direction (disengagement direction of the main clutch 7) via the inner shaft 5 and the washer 21.

The controller detects the turning traveling from the vehicle speed, the steering angle, the lateral G, etc., or excites the electromagnet 19, controls the excitation current, and stops the excitation depending on the road surface condition.

When the electromagnet 19 is excited, the magnetic flux loop 113 is formed in the above magnetic path, the armature 17 is attracted, and the pilot clutch 15 is pressed and engaged with the rotor 33 to generate a pilot torque.

When the pilot torque is generated, a transmission torque is applied 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 to the ball cam 9, and the generated cam thrust force is the above-mentioned. Return spring 23
Also, the pressure plate 11 is moved forward against the counterforce of the pressure receiving surfaces 25 and 27, and the main clutch 7 is pressed and fastened.

When the electromagnetic coupling 1 is connected in this way, the driving force of the prime mover for rotating the rotating case 3 causes the rear differential to rotate from the inner shaft 5 via the power transmission system such as the drive pinion shaft described above, so that the rear differential is rotated. The vehicle is distributed to the left and right rear wheels to be in a four-wheel drive state, which improves the running performance on rough roads and the stability of the vehicle body.

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, the pressing force of the main clutch 7 changes, and the driving force sent to the rear wheels is changed. Is changed, the driving force distribution ratio between the front and rear wheels can be controlled.

For example, when the driving force distribution ratio is controlled during turning, the maneuverability 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, and the return spring 23 and the pressure receiving surface 25,
With each counter force 27, the pressure plate 11 returns to the rear, the main clutch 7 is released, and the coupling of the electromagnetic coupling 1 is released.

When the coupling of the electromagnetic coupling 1 is released, the rear differential side is disconnected and the vehicle is in the two-wheel drive state of front wheel drive, so that the fuel economy of the prime mover, the turning performance and the straight running performance are improved.

Even if the excitation of the electromagnet 19 is stopped, it is unavoidable that drag torque is generated in the pilot clutch 15 due to the viscosity of the oil, and this drag torque is amplified by the ball cam 9 and the return spring 23 described above.
When the counter force of the pressure receiving surfaces 25 and 27 cannot be obtained, the pressure plate 11 is moved rearward to press the main clutch 7 to generate the residual torque (Td). And the effect of improving fuel economy and turning performance is reduced.

FIG. 5 shows the characteristics (current-torque characteristics) of the exciting current (I) and the transfer torque (T) of the electromagnet of the electromagnetic coupling.

A broken line graph 155 is a characteristic on the assumption that drag torque is not generated, and a solid line graph 15
7 is the characteristic when there is no drag torque canceling function (counterforce), and the solid line graph 159 shows the drag torque canceling function (counterforce).
It is a characteristic of the electromagnetic coupling 1 provided with. As shown in the graphs 155, 157 and 159, the exciting current (I) of the electromagnet and the transmission torque (T) are proportional.

When the drag torque is not generated as in the graph 155, the transmission torque (T) becomes zero when the exciting current (I) is set to zero (when the excitation of the electromagnet is stopped). As described above, when the drag torque cancel function is not provided, the residual torque (Td) due to the drag torque is generated even if the exciting current (I) is set to zero.

However, in the case of the electromagnetic coupling 1 shown by the graph 159, as described above, the counter force of the return spring 23 and the pressure receiving surfaces 25 and 27 pushes the pressure plate 11 back in the disengagement direction of the main clutch 7, Since the generation of the residual torque (Td) is prevented, if the excitation of the electromagnet 19 is stopped, the transmission torque (T) becomes zero and the coupling of the electromagnetic coupling 1 is completely completed, as in the case where the drag torque is not generated. Then, the vehicle is completely driven by two wheels.

Therefore, the response for switching to the two-wheel drive state becomes faster, and the fuel efficiency and turning performance are improved.

If the return spring 23 is replaced with one having a different biasing force (counter force),
An arbitrary current-torque characteristic parallel to the graph 159 of FIG. 5 is obtained, and by changing the current-torque characteristic in this way, the range of applicable vehicle types is widened.

The oil enclosed in the rotating case 3 is
The electromagnetic coupling 1 is circulated in the interior by receiving the centrifugal force generated by the rotation, and the main clutch 7, the ball cam 9, the pilot clutch 15, the spline parts 69, 73, 85, the thrust bearing 77, the washer 79, and the inner circumference of the cam ring 13. Is supplied to the sliding surface between the inner shaft 5 and the outer periphery of the inner shaft 5, the X ring 57, the sliding portion between the return spring 23, the flange portion 35, and the washer 111, and these are sufficiently lubricated and cooled.

The oil in the capacity increasing space 63 flows into the main clutch 7 side from the oil flow path 65 of the inner shaft 5 by centrifugal force, and is applied to the sliding surface between the outer plate 67 and the inner plate 71. The lubrication / cooling effect is further improved.

Further, an oil hole 115 is formed in each inner plate 71 of the main clutch 7, which promotes the movement of oil with respect to the sliding surface of each plate 67, 71 and improves the lubrication / cooling effect thereof. ing.

A through hole 117 is formed in the pressure plate 11 to reduce the movement resistance of the oil to improve the operation response of the main clutch 7, and the 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 / cooling effect of these is improved.

Thus, the electromagnetic coupling 1 is constructed.

The electromagnetic coupling 1 is, as described above,
By providing the counter force applying means (the return spring 23 and the pressure receiving surfaces 25, 27) for pushing back the pressure plate 11 in the disengagement direction of the main clutch 7, the residual torque due to the drag torque generated when the disengagement is prevented is prevented. As a result, the vehicle becomes completely in the two-wheel drive state, and the response to switch to the two-wheel drive state becomes faster, so that the fuel economy, turning performance, etc. can be sufficiently improved.

Also, by replacing the return spring 23 with one having a different biasing force, it is possible to adjust the current-torque characteristic in accordance with the type of vehicle to be mounted, the magnitude of the transmission torque to be handled, and the like. One model can be widely applied to different vehicle types.

Further, as described above, the return spring 23
With the electromagnetic coupling 1 whose current-torque characteristics can be adjusted simply by exchanging, the characteristics can be adjusted very easily compared to the conventional example in which the main clutch 507, pilot clutch 515, ball cam 509, electromagnet 519, etc., need to be changed. Therefore, the cost of adjusting the characteristics is significantly reduced.

Further, since the end portion of the inner shaft 5 and the flange portion 35 of the power transmission shaft 29 can be used as the seat surface of the return spring 23, it is not necessary to specially process the seat surface, and the cost can be reduced accordingly. With this structure, the return spring 23 is arranged at the end of the inner shaft 5, so that the return spring 23 can be easily assembled.

The pressure receiving surface 25 of the inner shaft 5,
By using 27 as a counter force applying means,
When the internal temperature rises, the drag torque is effectively canceled due to the increased oil pressure. Therefore, the return spring 23 and the pressure receiving surfaces 25 and 27 sufficiently cancel the drag torque in a wide temperature range from low temperature to high temperature. Is obtained.

[Second Embodiment] An electromagnetic coupling 201 (second embodiment of the present invention) will be described with reference to FIGS. 2, 4, and 5.

The electromagnetic coupling 201 has the features of claim 1,
It has the features of 2, 3, 4, 5, and 6. The electromagnetic coupling 201 is used in a four-wheel drive vehicle in place of the electromagnetic coupling 1 of the first embodiment. Less than,
The different points will be described with reference to the members having the same functions as those of the electromagnetic coupling 1 by giving the same reference numerals thereto. Further, the right side of FIG. 2 corresponds to the front of the vehicle (motor side), and members and the like without reference numerals are not shown.

The electromagnetic coupling 201 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,
Connecting means 203 (connecting means between the torque transmitting member and the pressing member), return spring 205 (spring: biasing member for applying an operating force in the opposite direction to the electromagnet: operating means: counterforce applying means), screw mechanism 207, pressure receiving surface Two
5, 27 (counterforce imparting means), a controller and the like.

In the case of the electromagnetic coupling 201, the rotating case 3 is composed of the power transmission shaft 29 and the cylindrical member 209 made of a strong material, the cylindrical member 211 made of stainless steel (non-magnetic material), the rotor 33, etc. The flange portion 35 of the power transmission shaft 29, the cylindrical member 209, and the cylindrical member 211 are welded together.

Further, the flange portion 35 of the power transmission shaft 29 is formed with a ring-shaped convex portion 213 concentric with the front end portion of the inner shaft 5.

The rotor 33 is screwed to the rear side opening of the cylindrical member 211 by the screw portion 215 provided between the rotor 33 and the rotor 33 and the cylindrical member 211 by the fitting portion 217 provided between them. Centered in the direction. Further, a nut 219 is screwed on the screw thread on the rotor 33 side of the screw portion 215, and the double nut function applies thrust force to the screw portion 215 to prevent loosening and enhances the fixing function.

On the inner circumference of the cylindrical members 209 and 211, there is provided a spline portion 69 to which the outer plates 67 and 81 of the main clutch 7 and pilot clutch 15 are connected.

Oil is injected into the inside of the rotating case 3 through an oil hole 221 formed in the flange portion 35 of the power transmission shaft 29. After the oil is injected, the oil hole 221 receives the steel ball 223. Pressed and sealed.

Between the cylindrical member 211 and the rotor 33,
An O-ring 225 is arranged to prevent oil leakage.

The rotating case 3 includes an X ring 57 and an O ring 2.
It is sealed by 25 and.

The front end of the inner shaft 5 has a flange portion 35 (power transmission shaft 2
It is supported by the convex portion 213 of 9) and is centered. By thus centering the front end of the inner shaft 5 by the ball bearing 227 and the convex portion 213 and centering the rear end by the needle bearing 53, the runout of the inner shaft 5 and the vibration of the electromagnetic coupling 201 are prevented. It is prevented.

The inner shaft 5 is axially positioned by the ball bearing 227, the snap rings 229 and 231, and the needle bearing 53 and the snap ring 55. Sliding with the needle bearing 53 and axial direction of the ball bearing 227. It is possible to move in the axial direction within a proper range depending on the play.

The connecting means 203 is composed of an end portion 235 of the spline portion 73 formed on the inner shaft 5 and an end portion 233 engaged with the end portion 235 on the inner circumference of the pressure plate 11. Thus, the inner shaft 5 and the pressure plate 11 are axially connected via the connecting means 203, and when the inner shaft 5 moves rearward, the pressure plate 11 is also moved rearward.

The pressure receiving surface 25 is formed on the front surface of the wall portion 237 that defines the capacity increasing space 63 in the hollow hole 51 of the inner shaft 5, and the pressure receiving surface 27 is formed on the front end portion of the inner shaft 5, and the oil receiving surface 25 is formed on the front surface of the inner shaft 5. The counter force generated by the pressure pushes the pressure plate 11 back in the disengagement direction of the main clutch 7.

The return spring 205 (disc spring) is
The flange portion 35 of the power transmission shaft 29 and the inner shaft 5
It is disposed in a bent state between the upper snap ring 231 and its counter force (biasing force) causes the pressure plate 11 to move in the disengaging direction of the main clutch 7 via the inner shaft 5 and the connecting means 203. Pushing back.

The snap ring 231 and the flange portion 35 are used as the seat surface of the return spring 205.

The return spring 205 has the first
Like the return spring 23 of the embodiment, it is used within the range 153 (FIG. 4) in which the counter force and the deflection are proportional.

The screw mechanism 207 comprises a pressing member 239, a screw portion 241 provided on the outer periphery of the power transmission shaft 29, nuts 243 and 245 screwed to the screw portion 241 and the like.

The pressing member 239 is a ring-shaped base 247.
And a plurality of leg portions 249, and each leg portion 249 passes through a plurality of through holes 251 provided in the flange portion 35 and faces the return spring 205. Through hole 251
An O-ring 253 is arranged between the leg portion 249 and the leg portion 249 to prevent oil leakage. Also, the base 247 is the nut 2
It is slidably engaged with a circumferential groove 255 provided in 43.

The nuts 243 and 245 are exposed to the outside. When the nut 243 is rotated, the pressing member 239 moves back and forth due to the step on the screw portion 241, the amount of bending of the return spring 205 changes, and the counter force is increased. Adjusted.

After adjusting the counter force, the nut 245 is tightened to prevent the nut 243 from loosening due to its double nut function, and to prevent the adjusted counter force from changing.

Even if the drag torque is generated in the pilot clutch 15, as shown by the graph 159 in FIG. 5, in the electromagnetic coupling 201, the counter force of the return spring 205 and the pressure receiving surfaces 25 and 27 causes the pressure plate 11 to contact the main clutch. By pushing back in the disconnecting direction of 7, the generation of residual torque (Td) is prevented.

Therefore, if the excitation of the electromagnet 19 is stopped,
The transmission torque (T) becomes zero and the electromagnetic coupling 20
The connection of 1 is completely released, the vehicle becomes a complete two-wheel drive state, the switching response to the two-wheel drive state becomes faster, and the fuel consumption and turning performance are improved.

If the deflection amount (counterforce) of the return spring 205 is changed by the screw mechanism 207 or the return spring 205 is replaced with a different biasing force (counterforce),
An arbitrary current-torque characteristic parallel to the graph 159 of FIG. 5 is obtained, and by changing the current-torque characteristic in this way, the range of applicable vehicle types is widened.

The oil enclosed in the rotating case 3 is
The electromagnetic clutch 201 is circulated in the interior by receiving the centrifugal force caused by the rotation, and the main clutch 7, the ball cam 9, the pilot clutch 15, the spline portions 69, 73, 85,
Thrust bearing 77, washer 79, cam ring 1
3, the sliding surface between the inner periphery of 3 and the outer periphery of the inner shaft 5, the X ring 57, the return spring 205 and the flange portion 35
And supplied to the sliding part with the snap ring 231 and the like,
Lubricate and cool them sufficiently.

In this way, the electromagnetic coupling 201 is constructed.

As described above, the electromagnetic coupling 201 is connected by providing the counter force applying means (the return spring 205 and the pressure receiving surfaces 25 and 27) that pushes back the pressure plate 11 in the disengagement direction of the main clutch 7. The residual torque due to the drag torque generated when the vehicle is released is prevented, the vehicle is in a complete two-wheel drive state, the response to switching to the two-wheel drive state is fast, and the fuel consumption, turning performance and straightness are sufficient. Can be improved.

The amount of bending of the return spring 205 may be changed by the screw mechanism 207, or the return spring 20 may be changed.
Unlike the conventional example, the electromagnetic coupling 201 whose current-torque characteristic can be adjusted by simply replacing 5 can easily adjust the characteristic at an extremely low cost.

When the amount of bending of the return spring 205 is adjusted by the screw mechanism 207 without replacing the return spring 205, the characteristics can be easily adjusted and the adjustment cost can be reduced.

Further, the amount of deflection (counterforce) of the return spring 205 is changed by the screw mechanism 207, or
Alternatively, if the return spring 205 is replaced with one having a different biasing force (counterforce), the current-torque characteristic can be adjusted according to the type of vehicle to be mounted, the magnitude of the transmission torque to be handled, and the like. One model can be widely applied to different vehicle types.

Further, since the screw mechanism 207 can finely adjust the current-torque characteristic (the amount of flexure of the return spring 205), it becomes possible to finely respond to the difference in the requirements which differ for each vehicle type, and the applicable vehicle type is further improved. To increase.

The screw mechanism 207 in which the nuts 243 and 245 are exposed to the outside can be operated from the outside, and it is not necessary to disassemble the electromagnetic coupling 201 when adjusting the current-torque characteristic. The adjustment of the characteristics is extremely easy, and the adjustment cost is further reduced.

Further, since the end portion of the inner shaft 5 is used as the seat surface of the return spring 205, it is not necessary to specially process the seat surface, the implementation cost is reduced by that much, and the end portion of the inner shaft 5 is reduced. The return spring 205 arranged at is easy to assemble.

Further, the pressure receiving surfaces 25 and 27 of the inner shaft 5 used for the counter force applying means and the return spring 205 can sufficiently cancel the drag torque in a wide temperature range from high temperature to low temperature.

[Third Embodiment] An electromagnetic coupling 301 (third embodiment of the present invention) will be described with reference to FIGS.

The electromagnetic coupling 301 is defined in claim 1.
It has the features of 2, 3, 4, 5, and 6. The electromagnetic coupling 301 is used in a four-wheel drive vehicle in place of the electromagnetic couplings 1,201 of the first and second embodiments. Hereinafter, the differences will be described with reference to the members having the same functions as those of the electromagnetic couplings 1 and 201 by giving the same reference numerals thereto. Further, the right side of FIG. 3 corresponds to the front of the vehicle (motor side), and members and the like without reference numerals are not shown.

The electromagnetic coupling 301 includes the rotating case 3, inner shaft 5, main clutch 7, ball cam 9, pressure plate 11, cam ring 13, pilot clutch 15, armature 17, electromagnet 19,
Connecting means 203 (connecting means for connecting torque transmitting member and pressing member), screw mechanism 303, return spring 305 (spring: biasing member for applying an operating force in the opposite direction to the electromagnet: operating means: counterforce applying means), intermediate member 307, pressure receiving surfaces 25 and 27 (counterforce applying means), a controller and the like.

The front end of the inner shaft 5 has a flange portion 35 (power transmission shaft 2
It is supported by the convex portion 39 of 9) and is centered. In this way, the front end of the inner shaft 5 is centered by the ball bearing 309 and the protrusion 39,
The centering of the rear end portion by the needle bearing 53 prevents the inner shaft 5 from swinging and the electromagnetic coupling 301 from vibrating.

The inner shaft 5 is axially positioned by the ball bearing 309, the stepped portion 311 of the flange portion 35, the needle bearing 53 and the snap ring 55. Outer race 3
Sliding with 13 allows axial movement within an appropriate range.

The screw mechanism 303 includes a screw hole 315 provided in the wall portion 237 of the inner shaft 5 and the screw hole 3
15 and a bolt 317 screwed to it. An O-ring 319 that prevents oil leakage is arranged between the bolt 317 and the wall portion 237.

Return spring 305 and intermediate member 30
7 are arranged inside the hollow hole 51 of the inner shaft 5 in this order toward the front.

The intermediate member 307 is a cylindrical member having a bottom on the rear side, and the leg portion 321 at the front end is the ball bearing 3.
It faces the outer race 313 of 09.

The return spring 305 (disc spring) is
It is arranged in a bent state between the bolt 317 and the intermediate member 307.

The return spring 305 pushes the inner shaft 5 rearward by its counter force (urging force), and pushes back the pressure plate 11 in the disengaging direction of the main clutch 7 via the connecting means 203.

Further, the return spring 305, like the return springs 23 and 205 of the first and second embodiments, has a range 153 in which the counter force is proportional to the deflection.
(Fig. 4).

Further, the circumferential groove 32 on the inner circumference of the inner shaft 5
A snap ring 327 having a convex portion 325 is attached to 3. This snap ring 327 has a convex portion 32.
5 is engaged with the leg portion 321 of the intermediate member 307, and the circumferential groove 323
The intermediate member 307 is prevented from rotating due to the sliding resistance with.

The bolts 317 are the hollow rotors 3 respectively.
3 and the inner shaft 5 are exposed to the outside, and when a hexagonal wrench is inserted into the hexagonal hole 329 of the bolt 317 and the rotary operation is performed, the bolt 3 is moved by the step on the screw hole 315.
17 moves back and forth, the amount of bending of the return spring 305 changes, and the counter force is adjusted.

Even if a drag torque is generated in the pilot clutch 15, as shown by the graph 159 in FIG. 5, in the electromagnetic coupling 301, the return spring 305 and the pressure receiving surface that push back the pressure plate 11 in the disengagement direction of the main clutch 7. The counter force of 25 and 27 prevents the residual torque (Td) from being generated.

Therefore, if the excitation of the electromagnet 19 is stopped,
The transmission torque (T) becomes zero and the electromagnetic coupling 30
The connection of 1 is completely released, the vehicle becomes a complete two-wheel drive state, the switching response to the two-wheel drive state becomes faster, and the fuel consumption and turning performance are improved.

If the deflection amount (counter force) of the return spring 305 is changed by the screw mechanism 303, or if the return spring 305 is replaced with one having a different biasing force (counter force),
An arbitrary current-torque characteristic parallel to the graph 159 of FIG. 5 is obtained, and by changing the current-torque characteristic in this way, the range of applicable vehicle types is widened.

In this way, the electromagnetic coupling 301 is constructed.

The electromagnetic coupling 301 is connected by providing the counter force applying means (return spring 305 and pressure receiving surfaces 25 and 27) for pushing back the pressure plate 11 in the disengagement direction of the main clutch 7 as described above. The residual torque due to the drag torque generated when the vehicle is released is prevented, the vehicle is in a complete two-wheel drive state, the response to switching to the two-wheel drive state is fast, and the fuel consumption, turning performance and straightness are sufficient. Can be improved.

The amount of bending of the return spring 305 may be changed by the screw mechanism 303, or the return spring 30 may be changed.
Unlike the conventional example, the electromagnetic coupling 301 whose current-torque characteristic can be adjusted by simply replacing 5 can easily adjust the characteristic at an extremely low cost.

When the amount of bending of the return spring 305 is adjusted by the screw mechanism 303 without replacing the return spring 305, the characteristics can be adjusted more easily and the adjustment cost can be reduced.

Further, the amount of deflection (counter force) of the return spring 305 is changed by the screw mechanism 303, or
Alternatively, if the return spring 305 is replaced with one having a different biasing force (counterforce), the current-torque characteristic can be adjusted according to the type of vehicle to be mounted, the magnitude of the transmission torque to be handled, and the like. One model can be widely applied to different vehicle types.

Further, since the screw mechanism 303 allows fine adjustment of the current-torque characteristic (the amount of deflection of the return spring 305), it becomes possible to finely respond to the difference in the requirements that differ for each vehicle type, and the applicable vehicle type is further improved. To increase.

Further, the screw mechanism 303 in which the bolt 317 is exposed to the outside can be operated from the outside, and in adjusting the current-torque characteristic, the electromagnetic coupling 3 is used.
01 is not required to be disassembled, the characteristic adjustment is extremely easy, and the adjustment cost is further reduced.

Further, the pressure receiving surfaces 25, 27 of the inner shaft 5 used for the counter force applying means and the return spring 305 can sufficiently cancel the drag torque in a wide temperature range from high temperature to low temperature.

In each embodiment, the main clutch 7 is a mechanism for transmitting the driving force between the rotating case 3 and the inner shaft 5, and the outer plate 6
7 and the inner plate 71 are meaningless, and the rotating case 3, the inner shaft 5, and the outer plate 67 are not meaningful.
The inner plate 71 and the inner plate 71 are both essential constituent members of the main clutch 7.

For the same reason, the rotating case 3, the cam ring 13, the outer plate 81, and the inner plate 83 are essential components of the pilot clutch 15.

The ball cam 9 (cam mechanism) is a mechanism for converting the transmitted driving torque into the pressing force of the main clutch 7, and includes the pressure plate 11, the cam ring 13, the cam surfaces formed on these, Not only the balls placed between the pressure plates 1
The inner shaft 5 for transmitting the driving force to 1, the rotating case 3 for transmitting the driving force to the cam ring 13, the pilot clutch 15 and the like are essential components.

In the electromagnetic coupling of the present invention, the electromagnet and the urging member for applying the urging force in the direction opposite to the attracting force to the friction clutch constitute the friction clutch operating means. It is possible to carry out both the positive operation configuration in which the friction clutch is excited by activating and the negative operation configuration in which the excitation of the electromagnet is stopped and the friction clutch is engaged by the biasing member.

Further, the pilot mechanism constituting the electromagnetic coupling of claim 6 is not only a pilot clutch mechanism using a friction clutch such as a multi-plate clutch, a single-plate clutch, 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 pilot clutch may be any type of clutch as long as it is a friction clutch, such as a single plate clutch or a cone clutch, in addition to the multi-plate clutch. Further, these may be wet type or dry type.

Further, the electromagnetic coupling of the present invention can be configured by an electromagnet, an armature and a friction clutch, unlike the configuration of claim 6 using a pilot mechanism and a cam mechanism. In this case, The armature becomes a pressing member that is given a counter force.

The electromagnetic coupling of the present invention can also be used in a differential limiting mechanism by disposing it between the differential rotating members of the differential gear.

[0170]

According to the electromagnetic coupling of the present invention, the counter force applying means for pushing back the pressing member in the disengagement direction of the friction clutch is replaced with a different counter force, and the type of vehicle to be mounted and the transmission torque to be handled. It is possible to adjust the current-torque characteristics according to the size of the vehicle, and it is possible to widely apply one model to different vehicle types.

Further, unlike the conventional example, the current-torque characteristic can be adjusted only by providing the counter force applying means or exchanging the counter force applying means. The characteristics can be easily adjusted, and the adjustment cost is extremely low.

Further, the drag torque generated in the friction clutch is canceled by the counter force, and this canceling function is particularly effective in the cold season when the viscosity of the oil becomes high or when the oil temperature does not rise completely.
If the electromagnetic coupling of the present invention is used in a four-wheel drive vehicle,
When the disengagement is released, the residual torque of the friction clutch is prevented, the vehicle enters the complete two-wheel drive state, and the response to change over to the two-wheel drive state is fast, and fuel consumption, turning performance, and straightness are sufficient. Can be improved.

The electromagnetic coupling of the second aspect can obtain the same effect as that of the first aspect.

Further, since one end of the torque transmitting member can be used as the seat surface of the spring (counterforce imparting means), it is not necessary to specially process the seat surface, and the cost can be reduced accordingly. Become.

Further, in the structure in which the spring is arranged at the end of the torque transmission member, the spring can be easily assembled.

The electromagnetic coupling of the third aspect can obtain the same effect as that of the second aspect.

By adjusting the bending amount of the spring with the screw mechanism, the current-torque characteristic can be adjusted at a further reduced cost without replacing the spring.

Further, it becomes possible to finely adjust the current-torque characteristic by the screw mechanism, and the number of applicable vehicles is further increased.

The electromagnetic coupling of claim 4 can obtain the same effect as that of the structure of claim 3.

Further, since the screw mechanism can be operated from the outside, it is not necessary to disassemble the electromagnetic coupling when adjusting the current-torque characteristics, the characteristics can be adjusted very easily, and the adjustment cost is greatly reduced. .

The electromagnetic coupling of the fifth aspect can obtain the same effects as those of the first to fourth aspects.

When the oil is at a high temperature, the drag torque is effectively canceled by the oil pressure applied to the pressure receiving surface, and when the oil is at a low temperature, the drag torque is canceled by a counter force such as a spring. A sufficient cancellation function of drag torque can be obtained in a wide temperature range up to.

The electromagnetic coupling of the sixth aspect can achieve the same effects as those of the first to fifth aspects.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a second embodiment.

FIG. 3 is a sectional view showing a third embodiment.

FIG. 4 is a graph showing a characteristic usage range of the return spring used in each embodiment.

FIG. 5 is a graph showing current-torque characteristics and the like of each embodiment.

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

[Explanation of symbols]

1 Electromagnetic Coupling 3 Rotating Case (Other Torque Transmission Member) 5 Inner Shaft (One Torque Transmission Member) 7 Main Clutch (Friction Clutch) 9 Ball Cam (Cam Mechanism) 11 Pressure Plate (Pressing Member) 15 Pilot Clutch (Pilot) Mechanism 19 electromagnet (operating means) 21 connecting means (connecting means between torque transmitting member and pressing member) 23 return spring (spring: biasing member for applying an operating force in the opposite direction of the electromagnet: operating means: counterforce applying means) 25, 27 Pressure-receiving surface (counterforce applying means) 201 Electromagnetic coupling 203 Coupling means (coupling means between torque transmitting member and pressing member) 205 Return spring (spring: biasing member for applying an operating force in the opposite direction to the electromagnet): Operation method: Counter Four 207 screw mechanism 301 electromagnetic coupling 303 screw mechanism 305 return spring (spring: biasing member for applying an operating force in the opposite direction to the electromagnet: operating means: counterforce applying means)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3D043 AA05 AA06 AB17 EA01 EA18                       EB03 EB05 EB07 EB12 EB13                       EE01 EE06 EE08 EE12 EF12                       EF19

Claims (6)

[Claims] 1. A pair of torque transmission members, a friction clutch arranged between the pair of torque transmission members, a pressing member of the friction clutch, and an electromagnet that applies an operating force to the pressing members in opposite directions. An electromagnetic coupling comprising an urging member and operating means for moving the pressing member by opening or closing the electromagnet to open or close the friction clutch by operating or stopping the electromagnet, wherein one of the pair of torque transmitting members is provided. And a pressing member are provided to connect the pressing member in the axial direction, and the pressing member is pushed back in the uncoupling direction of the friction clutch with a counter force of a predetermined strength via the one torque transmitting member and the connecting device. An electromagnetic coupling characterized by being provided with a counter force applying means. 2. The electromagnetic coupling according to claim 1, wherein the counter force applying means is a spring. 3. The electromagnetic coupling according to claim 2, further comprising a screw mechanism for adjusting a flexure amount of the spring. 4. The electromagnetic coupling according to claim 3, wherein the screw mechanism is operable from the outside by exposing the screw mechanism to the outside. 5. The invention according to any one of claims 1 to 4, wherein a space between the torque transmitting members is sealed by a seal, and oil is sealed, and the connecting means connects the pressing member with the pressing member. To one of the torque transmission members
An electromagnetic coupling, wherein a pressure receiving surface for returning the pressing member in the disengagement direction of the friction clutch by receiving the pressure of the enclosed oil is provided, and the counter force applying means is the pressure receiving surface. 6. The invention according to any one of claims 1 to 5, further comprising: a pilot mechanism which is operated and stopped by an operating means; and a cam mechanism, wherein the cam mechanism operates when the pilot mechanism operates. An electromagnetic coupling characterized in that a transmission torque is applied between the two torque transmission members, and the friction clutch is connected by a generated pressing force.