JP2012167783A - Drive force transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive force transmission device capable of pressing an armature of an electromagnetic clutch in an axial direction with force equal to or more than magnetic force by an electromagnet.SOLUTION: This drive force transmission device 1 includes: a housing 2 and an inner shaft 3 capable of being relatively rotated on the same axis; a main clutch 4 receiving thrust in an axial direction and connecting the housing 2 and the inner shaft 3 so that torque may be transmitted; a pilot clutch 5 actuated by the movement of an armature 52 receiving magnetic force of an electromagnet 51 toward an axial direction one side; a first cam mechanism 6 converting rotation force transmitted by the pilot clutch 5 to thrust for pressing the main clutch 4; and a second cam mechanism 7 generating thrust for pressing the armature 52 toward the axial direction one side by the relative rotation of the housing 2 and the armature 52.

Description

  The present invention relates to a driving force transmission device that transmits a driving force from an input shaft in an automobile to an output shaft, for example.

  2. Description of the Related Art Conventionally, for example, a driving force transmission device that is provided in a torque transmission path that transmits the driving force of an engine of a four-wheel drive vehicle to auxiliary driving wheels and that can control transmission torque from an input shaft to an output shaft is known (for example, Patent Document 1).

  The driving force transmission device described in Patent Document 1 includes an outer rotating member and an inner rotating member, a main clutch disposed between these rotating members, and a first non-rotatable relative to the outer rotating member. A piston, a second piston provided so as not to rotate relative to the inner rotating member, and two outer and inner rings. The first piston and the outer ring constitute a first cam mechanism, A second cam mechanism is constituted by the two pistons and the inner ring.

  A pilot clutch that is operated by electromagnetic force is disposed between the inner and outer two rings. The pilot clutch includes an armature that is attracted to the electromagnet side by the magnetic force of the electromagnet, and a plurality of clutch disks and a plurality of clutch plates that are pressed in the axial direction by the armature and frictionally slide with each other. A plurality of clutch disks are spline-fitted on the outer ring, and a plurality of clutch plates are spline-fitted on the inner ring.

  This driving force transmission device suppresses the relative rotation of the two inner and outer rings by the operation of the pilot clutch, and generates torque that relatively rotates the first piston and the outer ring, and the second piston and the inner ring. The torque generated by the pilot clutch is converted into a thrust force that presses the main clutch in the first cam mechanism and the second cam mechanism.

JP-A-10-281184

  However, since the force that presses the plurality of clutch disks and the plurality of clutch plates of the pilot clutch is caused solely by the magnetic force acting on the armature, the electromagnet needs to act on the armature with a magnetic force corresponding to the thrust that pushes the main clutch. . For this reason, there have been restrictions on miniaturization and power saving of the electromagnet.

  Therefore, an object of the present invention is to press the armature of the electromagnetic clutch in the axial direction with a force greater than the magnetic force of the electromagnet, and to arrange the torque transmitted by the electromagnetic clutch between the first rotating member and the second rotating member. Another object of the present invention is to provide a driving force transmission device that can be converted into thrust of a main clutch.

[1] A first rotating member and a second rotating member that are coaxially rotatable relative to each other, and are connected to the first rotating member and the second rotating member so as to be able to transmit torque by receiving axial thrust. A main clutch, an armature that receives a magnetic force of an electromagnet, and an electromagnetic clutch that is operated by the movement of the armature toward one axial direction by the magnetic force; and a rotational force transmitted by the electromagnetic clutch is converted into the thrust. A driving force transmission device comprising: a first cam mechanism; and a second cam mechanism that presses the armature to one side in the axial direction by relative rotation between the first rotating member and the armature.

[2] The armature includes a cam portion having a cam surface formed on a side surface opposite to the electromagnet, and the second cam mechanism includes the cam portion of the armature and the first rotating member. The driving force transmission device according to [1], further including a first cam member that is provided in a relatively non-rotatable manner and has a cam surface that is axially opposed to the cam portion of the armature.

[3] In the armature, the center of the cam surface in the radial direction with respect to the rotation shaft of the first rotating member and the second rotating member is radially inward from the friction surface that generates the frictional force by the magnetic force. The driving force transmission device according to [2], which is positioned.

  According to the present invention, the armature of the electromagnetic clutch is pressed in the axial direction with a force greater than the magnetic force of the electromagnet, and the torque transmitted by the electromagnetic clutch is disposed between the first rotating member and the second rotating member. It can be converted into clutch thrust.

The top view shown in order to demonstrate the outline of the vehicle by which the driving force transmission apparatus which concerns on embodiment of this invention is mounted. Sectional drawing shown in order to demonstrate the whole driving force transmission device which concerns on embodiment of this invention. (A) is the elements on larger scale which show the example of a structure of the pilot clutch in a non-operation state, a 1st cam mechanism, and a 2nd cam mechanism. (B) And (c) is a circumferential direction sectional view of the 1st cam mechanism and the 2nd cam mechanism. (A) is the elements on larger scale which show the example of a structure of the pilot clutch in a working state, a 1st cam mechanism, and a 2nd cam mechanism. (B) And (c) is a circumferential direction sectional view of the 1st cam mechanism and the 2nd cam mechanism.

  FIG. 1 shows a schematic configuration example of a four-wheel drive vehicle. The four-wheel drive vehicle 101 includes a driving force transmission device 1, an engine 102, a transaxle 103, left and right front wheels 104, and left and right rear wheels 105.

  The driving force transmission device 1 is disposed on a driving force transmission path from the front wheel side to the rear wheel side in the four-wheel drive vehicle 101 and is supported on a vehicle body (not shown) of the four-wheel drive vehicle 101 via a differential carrier 106. Has been.

  The driving force transmission device 1 connects the propeller shaft (input shaft) 107 and the drive pinion shaft (output shaft) 108 so that torque can be transmitted, and transmits the driving force of the engine 102 to the rear wheel 105 in this connected state. Configured to get. Details of the driving force transmission device 1 will be described later.

  The engine 102 as a driving source outputs the driving force to the front axle shaft 109 via the transaxle 103 to drive the left and right front wheels 104.

  The engine 102 outputs the driving force to the propeller shaft 107, the driving force transmission device 1, the drive pinion shaft 108, the rear differential 110, and the rear axle shaft 111 via the transaxle 103, so that the left and right rear wheels 105 are output. To drive.

[Overall configuration of the driving force transmission device 1]
FIG. 2 is a cross-sectional view illustrating a configuration example of the driving force transmission device 1. The driving force transmission device 1 includes a housing 2 as a first rotating member that can rotate relative to a coupling case 106a of a differential carrier 106 (shown in FIG. 1), and a first rotating member that can rotate relative to the housing 2 on the same axis. 2, an inner shaft 3 as a rotating member, a main clutch 4 as a main clutch that connects the inner shaft 3 and the housing 2 in an intermittent manner, and an electromagnetic clutch parallel to the main clutch 4 along its axis. A pilot clutch 5 and a first cam mechanism 6 that converts torque transmitted through the pilot clutch 5 into thrust of the main clutch 4 are provided.

  Furthermore, the driving force transmission device 1 converts a part of the driving force of the engine 102 transmitted to the housing 2 into axial thrust, and increases the rotational force transmitted through the pilot clutch 5. A mechanism 7 is provided.

(Configuration of housing 2)
The housing 2 includes a front housing 21 and a rear housing 22, and is accommodated in the coupling case 106a so as to be rotatable about the rotation axis O. The housing 2 is configured to receive the driving torque of the engine 102 (shown in FIG. 1) transmitted through the propeller shaft 107 (shown in FIG. 1) from the joint 107a and rotate.

  The front housing 21 has a bottomed cylindrical shape integrally including a bottom portion 211 and a cylindrical portion 212, and an accommodation space 21 a is formed inside the cylindrical portion 212. The housing space 21a is filled with lubricating oil (not shown) at a filling rate of 80%, for example. Further, the front housing 21 is supported rotatably around the rotation axis O by a ball bearing 81 arranged between the inner surface of the coupling case 106a.

  Of the inner peripheral surface of the cylindrical portion 212 of the front housing 21, a straight spline fitting portion 212 a having spline grooves extending in parallel along the rotation axis O is provided in a region on the bottom 211 side. Further, a joint 107 a is fixed to the bottom portion 211 with a bolt 80.

  The rear housing 22 is screwed to the inner peripheral surface of the opening of the front housing 21 and is rotatably supported by the coupling case 106a via a tapered roller bearing 82. The rear housing 22 is provided with an annular housing space 22a that opens to the side opposite to the main clutch 4 side.

  The rear housing 22 includes first to third rear housing elements 221 to 223. The first rear housing element 221 is disposed on the inner peripheral side of the rear housing 22 and is entirely formed of a cylindrical member made of a magnetic material such as soft iron. A ball bearing 83 is arranged on the inner peripheral side of the first rear housing element 221 between the outer peripheral surface of the drive pinion shaft 108.

  The second rear housing element 222 is disposed on the outer peripheral side of the rear housing 22, and is entirely formed of a cylindrical member made of a magnetic material such as soft iron like the first rear housing element 221.

  The third rear housing element 223 is interposed between the first rear housing element 221 and the second rear housing element 222, and an annular ring for connecting the rear housing element, which is entirely made of a nonmagnetic material such as stainless steel. It is formed by a member.

(Configuration of inner shaft 3)
The inner shaft 3 is housed in the housing space 21 a of the front housing 21 and has a large diameter cylindrical portion 31 and a small diameter cylindrical portion 32. An annular step surface 3 a is formed between the large diameter cylindrical portion 31 and the small diameter cylindrical portion 32. The inner shaft 3 is supported so as to be rotatable relative to the housing 2 on the same axis by a ball bearing 84 disposed between the inner shaft 3 and the bottom 211 of the front housing 21. A straight spline fitting portion 31 a extending in parallel along the rotation axis O is provided on the outer peripheral surface of the large-diameter cylindrical portion 31.

  In addition, a straight spline fitting portion 3 b extending in parallel along the rotation axis O is provided on the inner peripheral surface of the inner shaft 3. A straight spline fitting portion 108a of the drive pinion shaft 108 is fitted to the straight spline fitting portion 3b so as not to be relatively rotatable.

(Configuration of main clutch 4)
The main clutch 4 is a friction type multi-plate clutch in which a plurality of inner clutch plates 40 and a plurality of outer clutch plates 41 (both in the present embodiment are both five) are alternately arranged along the axial direction. Moreover, the main clutch 4 is arrange | positioned between the housing 2 and the inner shaft 3, and is accommodated in the accommodation space 21a. The main clutch 4 frictionally engages adjacent clutch plates of the inner clutch plate 40 and the outer clutch plate 41, and releases the frictional engagement between the housing 2 and the inner shaft 3 (torque). Transmission) is configured to be connected.

  The inner clutch plate 40 has a straight spline fitting portion 40a on the inner peripheral portion thereof, and the straight spline fitting portion 40a is fitted to the straight spline fitting portion 31a so that the inner shaft 3 cannot rotate relative to the inner shaft 3 and moves in the axial direction. Connected as possible. Of the plurality of inner clutch plates 40, the inner clutch plate 40 at the end of the pilot clutch side functions as an input portion of the main clutch 4, and thrusts from a main cam 62 (described later) of the first cam mechanism 6 toward the main clutch 4. When this is received, the other inner clutch plate 40 and the outer clutch plate 41 are frictionally engaged by movement in the pressing direction by this thrust.

  The outer clutch plate 41 has a straight spline fitting portion 41a on the outer periphery thereof, and the straight spline fitting portion 41a is fitted to the straight spline fitting portion 212a so that it cannot rotate relative to the front housing 21 (housing 2). It is connected so as to be movable in the axial direction.

(Configuration of pilot clutch 5)
FIG. 3A is a partially enlarged view of FIG. 2 showing a configuration example of the pilot clutch 5, the first cam mechanism 6, and the second cam mechanism 7. This figure shows a non-operating state in which no excitation current is supplied to the electromagnet 51.

  The pilot clutch 5 includes an electromagnet 51 formed of an annular coil housed in the housing space 22 a of the rear housing 22, an armature 52 that receives the magnetic force of the electromagnet 51, and one sheet disposed between the armature 52 and the rear housing 22. And a wave washer 54 that presses the armature 52 away from the rear housing 22.

  The electromagnet 51 is supplied with an excitation current from a control device (not shown) and generates a magnetic force having a magnitude corresponding to the excitation current. The electromagnet 51 is supported by a yoke 50 made of a magnetic material fixed to the coupling case 106a.

  The armature 52 is made of an annular magnetic material, and is disposed so as to be relatively rotatable and axially movable with respect to the housing 2 in the accommodating space 21a. The armature 52 integrally includes a friction portion 521 having a friction surface 52a that frictionally slides with the clutch plate 53, and a cam portion 522 having a cam surface 52b.

  The clutch plate 53 is a friction plate made of a magnetic member formed in a ring shape, and a spline fitting portion 53a is formed at an inner peripheral end portion thereof. Further, the clutch plate 53 suppresses a short circuit of the magnetic flux between the inner peripheral portion of the rear housing 22 facing the first rear housing element 221 and the outer peripheral portion facing the second rear housing element 222. A plurality of arc-shaped openings 53b are provided.

  The wave washer 54 is an elastic body formed by bending a flat washer made of, for example, spring steel into a corrugated shape and having circumferential undulations. The wave washer 54 is accommodated in an annular recess 222 a provided in the second rear housing element 222 and urges the armature 52 in a direction away from the rear housing 22.

(Configuration of the first cam mechanism 6)
The first cam mechanism 6 includes a pilot cam 61 that receives the rotational force of the housing 2 transmitted via the clutch plate 53 of the pilot clutch 5, a main cam 62 that presses the main clutch 4 in the axial direction, and the pilot cam 61 and the main cam 62. And a cam ball 63 as a rolling element interposed therebetween. The pilot cam 61 is an example of the second cam member of the present invention, and the main cam 62 is an example of the third cam member of the present invention.

  The pilot cam 61 has a torque receiving portion 611 in which a spline fitting portion 61 a that fits the spline fitting portion 53 a of the clutch plate 53 is formed on the outer peripheral surface thereof, and a cam surface 61 b that rolls the cam ball 63. The cam portion 612 is integrally provided.

  The pilot cam 61 is restricted from moving in the axial direction by a thrust bearing 85 disposed between the rear housing 22 and the first rear housing element 221. The clutch plate 53 is connected to the pilot cam 61 so as not to rotate relative to the pilot cam 61 and to be movable in the axial direction.

  The main cam 62 includes an annular pressing portion 621 that presses the main clutch 4, and a cam portion 622 in which a cam surface 62 b facing the cam surface 61 b of the pilot cam 61 in the axial direction is formed. The pressing portion 621 and the cam portion 622 are integrally provided in parallel in the axial direction, the pressing portion 621 is outside the large-diameter cylindrical portion 31 of the inner shaft 3, and the cam portion 622 is outside the small-diameter cylindrical portion 32. Respectively.

  A spline fitting portion 62 a that fits the straight spline fitting portion 31 a of the inner shaft 3 is provided on the inner peripheral surface of the pressing portion 621. Thereby, the main cam 62 is connected to the inner shaft 3 so as not to rotate relative to the inner shaft 3 and to be movable in the axial direction. A wave washer 64 that presses the main cam 62 against the rear housing 22 is disposed between the cam portion 622 and the step surface 3 a of the inner shaft 3.

  The cam ball 63 is sandwiched and held between the cam surface 61 b of the pilot cam 61 (cam portion 612) and the cam surface 62 b of the main cam 62 (cam portion 622), and both are rotated by the relative rotation of the pilot cam 61 and the main cam 62. The cam surfaces 61b and 62b roll. A plurality of (for example, six) cam balls 63 are arranged at equal intervals along the circumferential direction between the pilot cam 61 and the main cam 62.

(Configuration of the second cam mechanism 7)
The second cam mechanism 7 includes an annular cam member 71 projecting inward from the inner peripheral surface of the cylindrical portion 212 of the front housing 21, a cam portion 522 of the armature 52, and a cam of the cam member 71 and the armature 52. It is comprised from the cam ball 72 as a rolling element interposed between the parts 522. FIG. The second cam mechanism 7 is provided at a radially outer portion of the cam ball 63 of the first cam mechanism 6. The cam member 71 is an example of the first cam member of the present invention.

  The cam member 71 is disposed between the main clutch 4 and the armature 52, and is fixed to the front housing 21 so as not to be relatively rotatable and to be unable to move in the axial direction. The cam member 71 is a cam provided with a fixed portion 711 fixed to the inner surface of the front housing 21 at an outer peripheral portion thereof, and a cam surface 71b that rolls the cam ball 72 provided radially inward of the fixed portion 711. Part 712.

  A spline fitting portion 71 a is formed on a part of the outer surface of the fixing portion 711 on the main clutch 4 side. The spline fitting portion 71 a is fitted to the end portion of the straight spline fitting portion 212 a of the front housing 21. Moreover, the area | region in which the spline fitting part 71a is not formed among the outer peripheral surfaces of the fixing | fixed part 711 is formed in the cylindrical shape larger diameter than the spline groove part of the spline fitting part 71a. As a result, the cam member 71 is not rotatable relative to the front housing 21 and is restricted from moving in the axial direction.

  The cam ball 72 is sandwiched and held between the cam surface 71 b of the cam member 71 (cam portion 712) and the cam surface 52 b of the armature 52 (cam portion 522), and both the cam ball 71 and the armature 52 are rotated relative to each other. The cam surfaces 71b and 52b roll. A plurality of (for example, three) cam balls 72 are arranged at equal intervals along the circumferential direction between the cam member 71 and the armature 52 and held by a cage 73.

The radial center of the cam surface 52b of the armature 52 with respect to the rotation axis O is located at a radius r ₁ from the rotation axis O. Further, the inner peripheral end of the friction surface 52 a of the armature 52 is located at a radius r ₂ from the rotation axis O. As shown in FIG. 3 (a), the radius r ₂ is greater than the radius r _1, thus radial center of the cam surface 52b is located radially inward of friction surface 52a.

  FIG. 3B is a circumferential sectional view of the first cam mechanism 6, and FIG. 3C is a circumferential sectional view of the second cam mechanism 7.

  As shown in FIG. 3B, the cam surface 62b of the main cam 62 and the cam surface 61b of the pilot cam 61 are formed as inclined surfaces whose axial depth varies along the circumferential direction. In the neutral state shown in FIG. 3B (the inoperative state of the first cam mechanism 6), the cam ball 63 is located at the deepest portion of the cam surface 62b and the cam surface 61b. The main cam 62 and the pilot cam 61 are capable of relative rotation within a range in which the cam ball 63 rolls on the cam surfaces 62b and 61b.

  Further, as shown in FIG. 3C, the cam surface 71b of the cam member 71 and the cam surface 52b of the armature 52 are formed as inclined surfaces whose axial depth varies along the circumferential direction. In the neutral state shown in FIG. 3C (the non-operating state of the second cam mechanism 7), the cam ball 72 is located at the deepest part of the cam surface 71b and the cam surface 52b. The cam member 71 and the armature 52 can rotate relative to each other within a range in which the cam ball 72 rolls on the cam surfaces 71b and 52b.

[Operation and Action of Driving Force Transmission Device 1]
Next, the operation and action of the driving force transmission device 1 will be described with reference to FIGS.
4 shows the configuration of each part in the operating state of the driving force transmission device 1. FIG. 4A shows the pilot clutch 5, the first cam mechanism 6 and the second cam mechanism 7, and FIG. 4B shows the first cam mechanism 6. FIG. (C) shows the second cam mechanism 7 respectively.

  When no exciting current is supplied to the electromagnet 51, the magnetic force of the electromagnet 51 does not act on the armature 52, and the armature 52 is separated from the rear housing 22 by the elastic force of the wave washer 54 as shown in FIG. In the position. In this state, the clutch plate 53 of the pilot clutch 5 rotates without receiving the rotational force from the housing 2.

  In this case, since the torque from the clutch plate 53 is not transmitted to the torque receiving portion 611 of the pilot cam 61, the rotational force for rotating the main cam 62 and the pilot cam 61 does not act, and the first cam mechanism 6 is in an inoperative state. It becomes. In this state, the main cam 62 is pressed away from the main clutch 4 by the elastic force of the wave washer 64, and the inner clutch plate 40 and the outer clutch plate 41 of the main clutch 4 are not frictionally engaged.

  On the other hand, when an exciting current is supplied to the electromagnet 51, the yoke 50, the second rear housing element 222, the outer peripheral portion of the clutch plate 53, the armature 52, the inner peripheral portion of the clutch plate 53, and the first rear housing element 221. A rotating magnetic field having a magnetic path is generated, and the armature 52 is attracted to the rear housing 22 side by a magnetic force.

  As a result, as shown in FIG. 4A, the clutch plate 53 is sandwiched between the armature 52 and the rear housing 22, and friction is generated between the clutch plate 53 and the armature 52 and between the clutch plate 53 and the rear housing 22. Force is generated.

  When the housing 2 and the inner shaft 3 are differentially rotated in this state, the rotational force of the housing 2 is transmitted to the pilot cam 61 by the frictional force between the rear housing 22 and the clutch plate 53. 4B, the pilot cam 61 rotates relative to the main cam 62, the cam ball 63 rolls on the cam surfaces 62b and 61b, and the main cam 62 is separated from the pilot cam 61 in the axial direction. To do.

  Thus, the first cam mechanism 6 converts the transmitted rotational force into a thrust force that presses the main clutch 4, and the main cam 62 presses the main clutch 4 against the elastic force of the wave washer 64. As a result, the inner clutch plate 40 and the outer clutch plate 41 of the main clutch 4 are frictionally engaged, and the driving force is transmitted between the housing 2 and the inner shaft 3.

  Further, due to the frictional force between the clutch plate 53 and the armature 52, the armature 52 rotates relative to the cam member 71 of the second cam mechanism 7, as shown in FIG. As a result, the cam ball 72 rolls on the cam surfaces 71 b and 52 b, and the armature 52 receives thrust in a direction away from the cam member 71. By this thrust, the armature 52 is more strongly pressed against the rear housing 22 side, and the frictional force between the clutch plate 53 and the rear housing 22 is increased. That is, the armature 52 is pressed against the rear housing 22 by the resultant force of the attractive force generated by the magnetic force of the electromagnet 51 and the thrust generated by the second cam mechanism 7.

  When the armature 52 receives thrust from the second cam mechanism 7, a larger load is applied to the clutch plate 53 than when the armature 52 receives only the magnetic force of the electromagnet 51, and the clutch plate 53, the armature 52, and the rear housing 22 The frictional force increases. Therefore, the pilot cam 61 and the main cam 62 are relatively rotated at a larger angle, and the pressing force of the main clutch 4 is increased.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) The maximum value of the driving force that can be transmitted between the housing 2 and the inner shaft 3 because the clutch plate 53 can be pressed with a larger load than when the armature 52 is attracted only by the magnetic force of the electromagnet 51. Can be increased.

(2) Since there is only one clutch plate 53 of the pilot clutch 5, for example, the viscosity of the lubricating oil during non-operation is compared with a case where a plurality of outer clutch plates and inner clutch plates are alternately arranged in the electromagnetic clutch. The drag torque due to can be reduced.

(3) Compared to the case where the second cam mechanism 7 is not provided, the main clutch 4 can be pressed with a small exciting current, so that the power consumption of the electromagnet 51 can be reduced.

(4) Since the center in the radial direction of the cam surface 52b of the armature 52 is located radially inward of the friction surface 52a, for example, the center in the radial direction of the cam surface 52b is within the axial projection region of the friction surface 52a. The thrust of the armature 52 by the second cam mechanism 7 can be increased as compared with the case where the armature 52 is disposed.

(5) Since the second cam mechanism 7 is provided radially outside the position where the cam ball 63 of the first cam mechanism 6 is disposed, an increase in the axial length of the driving force transmission device 1 is suppressed. The That is, since the second cam mechanism 7 is disposed in a space formed in the outer peripheral portion of the cam ball 63, the axial dimension of the driving force transmission device 1 is secured in order to secure a space for disposing the cam member 71 and the cam ball 72. Is suppressed from becoming longer.

  The driving force transmission device of the present invention has been described based on the above embodiment, but the present invention is not limited to the above embodiment, and may be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the embodiment described above, the cam member 71 cannot be rotated relative to the front housing 21 and cannot move in the axial direction by the fixing portion 711 having the spline fitting portion 71a formed on a part of the outer peripheral surface of the cam member 71. Although fixed, the cam member 71 may be fixed to the inner surface of the front housing 21 by fixing means such as press fitting or welding. Further, the cam member 71 may be provided integrally with the cylindrical portion 212 of the front housing 21.

(2) In the above embodiment, the case where the armature 52 integrally includes the friction portion 521 and the cam portion 522 has been described. However, the friction portion 521 and the cam portion 522 are parallel to each other in the axial direction because the relative rotation is restricted. You may be comprised from two arrange | positioned members.

(3) In the above embodiment, the case where the first cam mechanism 6 and the second cam mechanism 7 have the cam ball 63 and the cam ball 72 has been described. However, the present invention is not limited to this, and the first cam mechanism 6 and the second cam mechanism 7. These cam surfaces may be configured to slide in direct contact with each other.

(4) In the above embodiment, the driving force transmission device 1 is disposed between the propeller shaft 107 of the four-wheel drive vehicle 101 and the drive pinion shaft 108 connected to the rear differential 110. However, the present invention is not limited to this. For example, the driving force transmission device 1 may be disposed between the output member of the rear differential 110 and the rear axle shaft 111. Moreover, you may use the driving force transmission apparatus 1 for uses other than the use for transmitting the driving force of a motor vehicle.

DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 2 ... Housing, 3 ... Inner shaft, 3a ... Step surface, 3b ... Straight spline fitting part, 4 ... Main clutch, 5 ... Pilot clutch, 6 ... 1st cam mechanism, 7 ... 2nd Cam mechanism, 21 ... front housing, 21a ... housing space, 22 ... rear housing, 22a ... housing space, 31 ... large diameter cylindrical portion, 31a ... straight spline fitting portion, 32 ... small diameter cylindrical portion, 40 ... inner clutch Plate, 40a ... Straight spline fitting portion, 41 ... Outer clutch plate, 41a ... Straight spline fitting portion, 50 ... Yoke, 51 ... Electromagnet, 52 ... Armature, 52a ... Friction surface, 52b ... Cam surface, 53 ... Clutch plate 53a ... Spline fitting part, 53b ... Opening part, 54 ... Wave washer, 61 ... Pilot cam 61a ... Spline fitting portion, 61b ... Cam surface, 62 ... Main cam, 62a ... Spline fitting portion, 62b ... Cam surface, 63 ... Cam ball, 64 ... Wave washer, 70 ... Main cam, 71 ... Cam member, 71a ... Spline fitting Joint part, 71b ... cam surface, 72 ... cam ball, 73 ... cage, 80 ... bolt, 81, 83,84 ... ball bearing, 82 ... conical roller bearing, 85 ... thrust bearing, 101 ... four-wheel drive vehicle, 102 ... Engine 103 ... Transaxle 104 ... Front wheel 105 ... Rear wheel 106 ... Differential carrier 106a ... Coupling case 107 ... Propeller shaft 107a ... Fitting 108 ... Drive pinion shaft 108a ... Straight spline fitting part 109 ... Front axle shaft, 110 ... Rear differential 111 ... Rear axle shaft 211 ... Bottom part 212 ... Cylindrical part 212a ... Straight spline fitting part 221-223 ... First to third rear housing elements 222a ... Recess 521 ... Friction part 522 ... Cam Department, 611 ... torque receiving portion, 612 ... cam portion, 621 ... pressing portion, 622 ... cam portion, 711 ... fixing portion, 712 ... cam portion, O ... rotation axis, _{r 1,} r 2 _... radius

Claims (3)

A first rotating member and a second rotating member that are relatively rotatable on the same axis;
A main clutch that receives axial thrust and connects the first rotating member and the second rotating member so as to transmit torque;
An electromagnetic clutch that has an armature that receives the magnetic force of an electromagnet, and that operates by moving the armature to one side in the axial direction by the magnetic force;
A first cam mechanism for converting a rotational force transmitted by the electromagnetic clutch into the thrust;
A driving force transmission device comprising: a second cam mechanism that presses the armature to the one side in the axial direction by relative rotation between the first rotating member and the armature. The armature has a cam portion in which a cam surface is formed on a side surface opposite to the electromagnet,
The second cam mechanism is provided such that the cam portion of the armature and the first rotating member are relatively non-rotatable, and the cam surface of the armature is formed with a cam surface facing in the axial direction. The driving force transmission device according to claim 1, further comprising: a cam member.   In the armature, the center of the cam surface in the radial direction with respect to the rotation axis of the first rotating member and the second rotating member is positioned radially inward from a friction surface that generates a frictional force by the magnetic force. The driving force transmission device according to claim 2.

Images