JP2015129574A - Driving force transmission device and electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving force transmission device which increases a transmittable driving force (torque) while inhibiting increase in the number of components and assembly work hours, and to provide an electromagnetic clutch.SOLUTION: An electromagnetic clutch mechanism 5 of a driving force transmission device 2 includes: an armature 50; multiple pilot outer clutch plates 51; multiple pilot inner clutch plates 52; an electromagnetic coil 53; and a magnet ring 6 disposed in a position which is located between a front housing 21 and the pilot inner clutch plate 52 and faces the pilot outer clutch plate 51 in an axial direction.

Description

  The present invention relates to a driving force transmission device and an electromagnetic clutch.

  2. Description of the Related Art Conventionally, there is a driving force transmission device that is mounted on, for example, a four-wheel drive vehicle and connects a pair of rotating members so that torque can be transmitted by a clutch (see, for example, Patent Document 1).

  A driving force transmission device described in Patent Document 1 includes an inner rotating member and an outer rotating member that are coaxially and relatively rotatable, a main clutch that connects the inner rotating member and the outer rotating member so as to be able to transmit torque, and a main clutch. The first cam mechanism that generates a pressing force to be pressed and the electromagnetic force that activates the first cam mechanism by transmitting the rotational force of the outer rotating member by the frictional force generated by the axial movement of the armature by the magnetic force of the electromagnetic coil. And a clutch mechanism.

  In addition, the driving force transmission device described in Patent Document 1 has a first cam member and a second cam member in the first cam mechanism for the purpose of pressing the armature in the axial direction with a force greater than the magnetic force of the electromagnetic coil. And a second cam mechanism for separating the second cam member and the armature in the axial direction according to relative rotation with each other. The second cam mechanism is a third cam which rotates relative to the second cam member by the rotation of the planetary gear disposed between the first cam member and the second cam member in the first cam mechanism. The third cam member has a cam member, and is configured to press the armature.

  In the driving force transmission device described in Patent Document 1, the armature is pressed against the electromagnetic coil side by the second cam mechanism, and the second cam member is pressed against the main clutch side. It is possible to increase the driving force that can be transmitted between the two.

JP 2012-189203 A

  According to the driving force transmission device described in Patent Document 1, the armature is pressed in the axial direction by a force greater than the magnetic force of the electromagnetic coil by the second cam mechanism, and the transmittable driving force can be increased. Since the configuration of the second cam mechanism is complicated, the number of parts and the number of assembling steps are greatly increased in order to add the second cam mechanism. Further, since the second cam mechanism is accommodated, the axial lengths of the outer rotating member and the inner rotating member may be increased. The driving force transmission device described in Patent Document 1 still has room for improvement in these respects.

  Accordingly, an object of the present invention is to provide a driving force transmission device and an electromagnetic clutch capable of increasing a transmittable driving force (torque) while suppressing an increase in the number of parts and assembly man-hours.

  In order to achieve the above-mentioned object, the present invention can transmit torque between the inner rotating member and the outer rotating member, which can be relatively rotated on the same axis, and the inner rotating member and the outer rotating member by receiving axial pressing force. A main clutch coupled to the first cam member, and a first cam member and a second cam member. The main cam is coupled to the second cam member by rotating the first cam member relative to the second cam member. A cam mechanism that generates a pressing force to be pressed; and an electromagnetic clutch mechanism that operates the cam mechanism in response to a rotational force of the outer rotating member, the electromagnetic clutch mechanism generating an electromagnetic flux when energized; Engage with the armature that moves in the axial direction by the magnetic force generated by energization of the electromagnetic coil and a plurality of inner peripheral spline protrusions formed on the outer rotating member, and Engage with the outer clutch plate connected to the member so as not to rotate relative to the member and to be movable in the axial direction, and a plurality of outer peripheral spline protrusions formed on the first cam member, and rotate relative to the first cam member. Impossible and axially movable inner clutch plate, and disposed between the outer rotating member and the inner clutch plate at a position facing the outer clutch plate in the axial direction and generated by the electromagnetic coil A driving force transmission device having an annular magnetic body that allows a magnetic flux to pass therethrough is provided.

  In order to achieve the above object, the present invention is an electromagnetic clutch that connects a first member and a second member that are coaxially arranged to be relatively rotatable so that torque can be transmitted, and is formed on the first member. A plurality of spline protrusions formed on the second member and the first clutch plate engaged with the plurality of spline protrusions and connected to the first member so as not to rotate relative to the first member and to be axially movable. A second clutch plate coupled to the second member so as not to be rotatable relative to the second member and movable in the axial direction; an electromagnetic coil that generates a magnetic flux when energized; and an armature that moves in the axial direction by a magnetic force generated by the magnetic flux. And disposed between the first member and the second clutch plate in a position facing the first clutch plate in the axial direction, and passes a magnetic flux generated by the electromagnetic coil. To provide an electromagnetic clutch having a magnetic annular be.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to increase the drive force (torque) which can be transmitted, suppressing the increase in a number of parts and an assembly man-hour.

1 is a schematic configuration diagram illustrating a configuration example of a four-wheel drive vehicle equipped with a driving force transmission device according to a first embodiment of the present invention. It is sectional drawing which shows the structural example of a driving force transmission apparatus. The inner surface of a front housing is shown, (a) is a whole perspective view, (b) is the partially expanded view of (a). (A) is a top view of a pilot outer clutch plate, (b) is a top view of a pilot inner clutch plate. (A) is a top view of an armature, (b) is the sectional view on the AA line of (a). The structural example of a magnetic ring is shown, (a) is a top view, (b) is the BB sectional drawing of (a). It is an enlarged view of an electromagnetic clutch mechanism and its periphery. It is sectional drawing which shows the structural example of the electromagnetic clutch which concerns on the 2nd Embodiment of this invention.

[First Embodiment]
FIG. 1 is a schematic configuration diagram showing a configuration example of a four-wheel drive vehicle equipped with a driving force transmission device according to a first embodiment of the present invention.

  The four-wheel drive vehicle 1 includes an engine 102 as a drive source, a transaxle 103 having a transmission and a front differential, a pair of front wheels 104, a pair of rear wheels 105, a rear differential carrier 106, and a propeller shaft 107. The control device 10 and the driving force transmission device 2 are provided.

  The driving force transmission device 2 is disposed on a driving force transmission path from the front wheel side to the rear wheel side in the four-wheel drive vehicle 1 and is supported by the vehicle body 101 via a rear differential carrier 106. The driving force transmission device 2 connects the propeller shaft (input shaft) 107 and the drive pinion shaft (output shaft) 108 so that torque can be transmitted. In this connected state, the driving force of the engine 102 is transmitted to the pair of rear wheels 105. It is configured to be able to communicate.

  The driving force transmission device 2 receives supply of current from the control device 10 and transmits driving force corresponding to the current from the propeller shaft 107 to the drive pinion shaft 108. The control device 10 supplies, for example, a current to be supplied to the driving force transmission device 2 based on a difference in rotational speed between the pair of front wheels 104 and the pair of rear wheels 105, an acceleration operation amount (accelerator pedal depression amount) by the driver, and the like. Increase / decrease control.

  With the above configuration, the engine 102 drives the pair of front wheels 104 by outputting the driving force to the front axle shaft 109 via the transaxle 103. Further, the engine 102 outputs the driving force to the rear axle shaft 111 via the transaxle 103, the propeller shaft 107, the driving force transmission device 2, the drive pinion shaft 108, and the rear differential 110, whereby a pair of rear wheels is output. 105 is driven.

(Configuration of the driving force transmission device 2)
FIG. 2 is a cross-sectional view illustrating a configuration example of the driving force transmission device 2. In FIG. 2, the upper side of the rotation axis O indicates the operating state (torque transmission state) of the driving force transmission device 2, and the lower side indicates the non-operational state (torque non-transmission state) of the driving force transmission device 2.

  The driving force transmission device 2 includes a housing 20 as an outer rotating member composed of a front housing 21 and a rear housing 22, and a cylindrical inner shaft 23 as an inner rotating member supported coaxially with the housing 20 so as to be relatively rotatable. The main clutch 3 that connects the housing 20 and the inner shaft 23 so as to transmit torque, the cam mechanism 4 that generates a pressing force that presses the main clutch 3, and the cam mechanism 4 that receives the rotational force of the front housing 21 are operated. And an electromagnetic clutch mechanism 5 to be configured.

  The housing 20 is configured by combining a bottomed cylindrical front housing 21 and an annular rear housing 22 that covers a part of the opening side of the front housing 21. Lubricating oil (not shown) is sealed in the internal space of the housing 20.

(Configuration of front housing 21)
The configuration of the front housing 21 will be described with reference to FIGS. 3A and 3B show the inner surface of the front housing 21, wherein FIG. 3A is an overall perspective view and FIG. 3B is a partially enlarged view of FIG.

  The front housing 21 integrally includes a cylindrical portion 21a and a bottom portion 21b, and a female screw portion 21c is formed on the inner surface at the open end of the cylindrical portion 21a. The front housing 21 is made of a nonmagnetic material such as aluminum, and the propeller shaft 107 (see FIG. 1) is connected to the bottom 21b so as not to be relatively rotatable through, for example, a cross joint.

  On the inner peripheral surface of the cylindrical portion 21a, an inner peripheral spline portion comprising a plurality of first inner peripheral spline protrusions 211 extending in the rotation axis direction and a plurality of second inner peripheral spline protrusions 212 extending in the rotation axis direction. 210 is formed. The first inner peripheral spline protrusion 211 and the second inner peripheral spline protrusion 212 are formed to protrude in the radial direction from the inner peripheral surface 21d of the front housing 21 toward the rotation axis O (shown in FIG. 1).

  As shown in FIG. 2, the inner peripheral spline portion 210 includes a first region 210 a in which a main outer clutch plate 31 described later engages with the first inner peripheral spline protrusion 211 and the second spline protrusion 212, and will be described later. The armature 50, the magnetic ring 6, and the second region 210b in which the pilot outer clutch plate 51 is spline-engaged are provided. The first inner peripheral spline protrusion 211 is formed over the first area 210a and the second area 210b, and the second spline protrusion 212 is formed only in the first area 210a.

  The number of first inner peripheral spline protrusions 211 is smaller than the number of second spline protrusions 212. In the present embodiment, the inner peripheral spline portion 210 is constituted by four first inner peripheral spline protrusions 211 and 28 second inner peripheral spline protrusions 212. The four second inner peripheral spline protrusions 211 are formed at four locations at equal intervals in the circumferential direction with respect to the rotation axis O.

  An end surface 211a (see FIG. 3B) of the first inner peripheral spline protrusion 211 on the opening side (second region 210b side) of the front housing 21 is opposed to the axial end surface of the rear housing 22. An end face 212a on the opening side of the front housing 21 of the second inner peripheral spline protrusion 212 faces an axial end face 500a on the main clutch 3 side of the armature 50 described later.

(Configuration of rear housing 22)
As shown in FIG. 2, the rear housing 22 includes a first annular member 221 made of a magnetic material such as iron, and a nonmagnetic material such as austenitic stainless steel integrally joined to the inner peripheral side of the first annular member 221 by welding or the like. A second annular member 222 made of a material, and a third annular member 223 made of a magnetic material such as iron integrally coupled to the inner peripheral side of the second annular member 222 by welding or the like. Between the 1st annular member 221 and the 3rd annular member 223, the cyclic | annular accommodation space 22a which accommodates the electromagnetic coil 53 mentioned later is formed. Further, a male screw portion 221 a that is screwed into the female screw portion 21 c of the front housing 21 is formed on the outer peripheral surface of the first annular member 221.

(Configuration of the inner shaft 23)
The inner shaft 23 is supported on the inner peripheral side of the housing 20 by a ball bearing 81 and a needle roller bearing 82. An outer peripheral spline portion 230 including a plurality of outer peripheral spline protrusions 231 extending in the rotation axis direction is formed on the outer peripheral surface of the inner shaft 23. Also, a spline fitting portion 232 is formed on the inner surface of one end portion of the inner shaft 23 so that one end portion of the drive pinion shaft 108 (see FIG. 1) is fitted so as not to be relatively rotatable.

(Configuration of main clutch 3)
The main clutch 3 is a wet type having a plurality of main outer clutch plates 31 as outer main clutch plates and a plurality of main inner clutch plates 32 as inner main clutch plates arranged alternately along the rotation axis O of the housing 20. It consists of a multi-plate clutch. On the outer peripheral portion of the main outer clutch plate 31, a plurality of protrusions 311 that are spline-engaged with the inner peripheral spline portion 210 of the front housing are provided. A plurality of projections 321 that are spline-engaged with the outer peripheral spline portion 230 of the inner shaft 23 are provided on the inner peripheral portion of the main inner clutch plate 32.

  The main outer clutch plate 31 is not rotatable relative to the front housing 21 and is movable in the axial direction. The main inner clutch plate 32 is not rotatable relative to the inner shaft 23 and is movable in the axial direction. The main inner clutch plate 32 is formed with a plurality of oil holes 322 for allowing the lubricating oil to flow therethrough.

(Configuration of cam mechanism 4)
The cam mechanism 4 includes a pilot cam 41 as a first cam member, a main cam 42 as a second cam member that presses the main clutch 3 in the axial direction, and a plurality of cam mechanisms 4 disposed between the pilot cam 41 and the main cam 42. And a spherical cam ball 43.

  The main cam 42 is a member made of, for example, iron that is a magnetic material, and comes into contact with the main inner clutch plate 32 at one end of the main clutch 3 to press the main clutch 3, and a pressing portion 421. In addition, a cam portion 422 provided on the inner peripheral side of the main cam 42 is integrally provided. The outer peripheral surface 421a of the pressing part 421 faces the inner peripheral spline part 210 (the first inner peripheral spline protrusion 211 and the second inner peripheral spline protrusion 212). An axial end surface 421b on the electromagnetic coil 53 side in the axial direction of the pressing portion 421 is opposed to an armature 50 described later.

  Further, the main cam 42 is formed with spline teeth 421 c that are spline-engaged with the outer peripheral spline portion 230 of the inner shaft 23 inside the pressing portion 421. Accordingly, the main cam 42 is not rotatable relative to the inner shaft 23 and is movable in the axial direction. A disc spring 44 that urges the main cam 42 toward the pilot cam 41 is disposed between the step surface 23 a formed on the inner shaft 23 and the main cam 42.

  A spline engaging portion 411 is formed on the outer peripheral portion of the pilot cam 41. A thrust needle roller bearing 45 is disposed between the pilot cam 41 and the third annular member 223 of the rear housing 22, and movement of the pilot cam 41 toward the rear housing 22 is restricted.

  A plurality of cam grooves 41 a and 422 a whose axial depth varies along the circumferential direction are formed on the opposing surface of the pilot cam 41 and the cam portion 422 of the main cam 42. A spherical cam ball 43 is disposed between the cam groove 41 a of the pilot cam 41 and the cam groove 422 a of the main cam 42. The cam mechanism 4 generates an axial pressing force that presses the main clutch 3 against the main cam 42 by rotating the pilot cam 41 relative to the main cam 42.

(Configuration of electromagnetic clutch mechanism 5)
The electromagnetic clutch mechanism 5 includes an armature 50, a plurality of pilot outer clutch plates 51, a plurality of pilot inner clutch plates 52, an electromagnetic coil 53, and a magnetic ring 6.

  The electromagnetic coil 53 is held by an annular yoke 530 made of a magnetic material and is accommodated in the accommodating space 22 a of the rear housing 22. The yoke 530 is supported by the third annular member 223 of the rear housing 22 by a ball bearing 83, and the outer peripheral surface thereof faces the inner peripheral surface of the first annular member 221. Further, the inner peripheral surface of the yoke 530 faces the outer peripheral surface of the third annular member 223. Excitation current is supplied to the electromagnetic coil 53 from the control device 10 (see FIG. 1) via the electric wire 531. The electromagnetic coil 53 generates magnetic flux when energized from the control device 10.

  4A is a plan view of the pilot outer clutch plate 51, and FIG. 4B is a plan view of the pilot inner clutch plate 52.

  The plurality of pilot outer clutch plates 51 and the plurality of pilot inner clutch plates 52 are alternately arranged between the armature 50 and the rear housing 22 along the rotation axis O (see FIG. 2).

  A plurality of recesses 511 that engage with the first inner peripheral spline protrusion 211 of the front housing 21 are formed in the outer peripheral portion of the pilot outer clutch plate 51 in the circumferential direction. As a result, the pilot outer clutch plate 51 is connected to the front housing 21 so as not to rotate relative to the front housing 21 and to be movable in the axial direction. In the present embodiment, four recesses 511 are formed at equal intervals along the circumferential direction.

  In the radial direction of the pilot outer clutch plate 51, a plurality of arc-shaped slits 510 extending in the circumferential direction are formed so as to be arranged in the circumferential direction between the inner peripheral edge and the outer peripheral edge. Further, the pilot outer clutch plate 51 has an outer friction surface 51 a located on the radially outer side of the slit 510 and an inner friction surface 51 b located on the radially inner side of the slit 510 as friction surfaces in the axial direction. . Further, the axial end surface 221b on the main cam 52 side of the first annular member 221 of the rear housing 22 is in contact with the outer peripheral end portion (portion sandwiched between the two concave portions 511 in the circumferential direction) of the pilot outer clutch plate 51. Thereby, a magnetic path through which the magnetic flux passes through the magnetic ring 6 described later is formed through this contact portion.

  On the inner peripheral portion of the pilot inner clutch plate 52, a plurality of protrusions 521 that are in contact with the plurality of spline protrusions 411 a provided on the spline engaging portion 411 of the pilot cam 41 in the circumferential direction are provided. Thus, the pilot inner clutch plate 52 is connected to the pilot cam 41 so as not to be relatively rotatable and to be movable in the axial direction. Further, in the radial direction of the pilot inner clutch plate 52, a plurality of arc-shaped slits 520 extending in the circumferential direction are formed in the circumferential direction between the inner peripheral edge and the outer peripheral edge.

  The plurality of slits 520 of the pilot inner clutch plate 52 are respectively formed at positions facing the plurality of slits 510 of the pilot outer clutch plate 51 in the axial direction. Further, the pilot inner clutch plate 52 has an outer friction surface 52a positioned on the radially outer side of the slit 520 and an inner friction surface 52b positioned on the radially inner side of the slit 520 as friction surfaces in the axial direction. . Further, the second annular member 222 of the rear housing 22 is disposed at a position facing the plurality of slits 510 of the pilot outer clutch plate 51 and the plurality of slits 520 of the pilot inner clutch plate 52.

(Configuration of armature 50)
Fig.5 (a) is a top view of the armature 50, FIG.5 (b) is the sectional view on the AA line of Fig.5 (a).

  The armature 50 is an annular member made of a magnetic material such as iron, and a plurality of (this embodiment) are engaged with the inner peripheral spline portion 210 (first inner peripheral spline 211) of the front housing 21 on the outer peripheral portion. Then, four) recesses 501 are formed. Thereby, the armature 50 is not rotatable relative to the front housing 21 and is movable in the axial direction. The axial end surface 500a on the main clutch 3 side of the armature 50 is opposed to the axial end surface 421b of the pressing portion 421 of the main cam 42 via a gap.

  When the electromagnetic coil 53 is energized, the armature 50 moves toward the electromagnetic coil 53 in the axial direction by the magnetic force generated by the magnetic flux generated by the electromagnetic coil 53. Further, as shown in FIG. 5B, the armature 50 is formed such that the axial end surface 500a on the main clutch 3 side in the axial direction is inclined with respect to the radial direction, and the axial thickness is radially inward. It is comprised so that it may become small gradually toward radial direction outer side. That is, the magnetic flux generated by energization of the electromagnetic coil 53 is concentrated on the radially inner side where the circumferential cross-sectional area becomes smaller. By making the thickness on the radially inner side thicker than the thickness on the radially outer side, the armature The armature 50 is reduced in weight while suppressing magnetic saturation at 50. Here, the inclination angle α formed by the axial end surface 500a and the radial direction of the armature 50 is, for example, 4 ° to 5 °.

(Configuration of magnetic ring 6)
6A is a plan view of the magnetic ring 6, and FIG. 6B is a cross-sectional view taken along the line BB of FIG. 6A. FIG. 7 is an enlarged view of the electromagnetic clutch mechanism 5 and its peripheral part.

  The magnetic ring 6 has an annular plate shape having a predetermined thickness in the axial direction, and is made of, for example, a magnetic material such as iron. Here, the predetermined thickness means that when the pilot outer clutch plate 51 and the pilot inner clutch plate 52 are pressed by the axial movement of the armature 50, the magnetic ring 6 is connected to the pilot outer clutch plate 51 and the pilot inner clutch plate 52. For example, the thickness of the pilot inner clutch plate 52 is smaller than or equal to the axial thickness.

  The magnetic ring 6 is disposed between the front housing 21 and the pilot inner clutch plate 52 at a position facing the pilot outer clutch plate 51 in the axial direction.

  In the present embodiment, the electromagnetic clutch mechanism 5 has three pilot outer clutch plates 51 and two pilot inner clutch plates 52, and the magnetic ring 6 is disposed outside each pilot inner clutch plate 52. . The magnetic ring 6 is disposed between the two adjacent pilot outer clutch plates 51. Furthermore, the axial end surface 6a of the magnetic ring 6 faces the pilot outer clutch plate 51 in the axial direction.

  On the outer periphery of the magnetic ring 6, a recess 60 is formed in which the first inner spline protrusion 211 can be engaged. In the present embodiment, four recesses 60 are formed at equal intervals along the circumferential direction. The magnetic ring 6 includes an arc portion 61 formed in an arc shape between a pair of recesses 60 adjacent in the circumferential direction, and a connecting portion 62 that connects the adjacent pair of arc portions 61 in the circumferential direction. Have The connecting portion 62 connects the pair of arc portions 61 inside the recess 60 (on the bottom surface 60a side).

  The inner peripheral surface 6b of the magnetic ring 6 is opposed to the outer peripheral surface 52c of the second inner clutch plate 51 via a gap. Thereby, the contact between the inner peripheral surface 6b of the magnetic ring 6 and the outer peripheral surface 52c of the pilot inner clutch plate 52 is prevented, and the magnetic ring 6 is configured not to interfere with the rotation operation of the pilot inner clutch plate 52.

  A housing groove 11 a that houses the O-ring 11 that seals the lubricating oil sealed inside the front housing 21 is formed on the outer circumferential surface of the first annular member 221. The housing groove 11 a is disposed closer to the axial end surface 221 b than the housing space 22 a on the outer peripheral surface of the first annular member 221 of the rear housing 22. Thereby, since the magnetic path area of the first annular member 221 is configured to be larger on the armature 50 side than on the electromagnetic coil 53 side, for example, when the O-ring 11 is disposed on the outer side of the accommodation space 22a. Compared to the above, magnetic saturation in the first annular portion 221 is suppressed.

(Operation of the driving force transmission device 2)
In the driving force transmission device 2 configured in this way, when an excitation current is supplied from the control device 10 to the electromagnetic coil 53, as shown in FIG. 7, the yoke 530, the first annular member 221 of the rear housing 22 and the first annular member 221. A magnetic path G through which magnetic flux passes through the three annular members 223, the plurality of pilot outer clutch plates 51, the plurality of pilot inner clutch plates 52, the magnetic ring 6, and the armature 50 is formed. Here, the pilot outer clutch plate 51, the pilot inner clutch plate 52, and the magnetic ring 6 are collectively referred to as a pilot clutch portion 7 hereinafter.

  The magnetic flux path in this magnetic path G is as follows: yoke 530 → first annular member 221 of rear housing 22 → outer peripheral portion of pilot clutch portion 7 (outside slits 510 and 520) → armature 50 → inner periphery of pilot clutch portion 7 Portion (inside slits 510 and 520) → third annular member 223 of rear housing 22 → yoke 530.

  On the outer peripheral side of the slit 510 and the slit 520, a part of the magnetic flux passes through the pilot outer clutch plate 51 and the pilot inner clutch plate 52, and the other part passes through the pilot outer clutch plate 51 and the magnetic ring 6.

  Thus, the armature 50 is attracted to the rear housing 22 side by the electromagnetic force of the electromagnetic coil 53 and moves in the axial direction to press the pilot outer clutch plate 51 and the pilot inner clutch plate 52.

  As a result, the pilot outer clutch plate 51 and the pilot inner clutch plate 52 frictionally slide, the rotational force of the housing 20 is transmitted to the pilot cam 41 of the cam mechanism 4, and the pilot cam 41 rotates relative to the main cam 42. That is, the electromagnetic clutch mechanism 5 applies a rotational force that causes the pilot cam 41 and the main cam 42 to rotate relative to each other when the electromagnetic coil 53 is energized.

  Due to the relative rotation of the pilot cam 41 and the main cam 42, the cam ball 43 rolls in the cam grooves 41a and 422a, and axial thrust is generated in the direction in which the pilot cam 41 and the main cam 42 are separated from each other. And the main cam 42 presses the main clutch 3 by this thrust, and the housing 20 and the inner shaft 23 are connected so that torque transmission is possible.

  On the other hand, when the exciting current to the electromagnetic coil 53 is interrupted, the main cam 42 is pushed back to the pilot cam 41 side by the biasing force of the disc spring 44, and the cam ball 43 moves to the deepest position in the cam grooves 41a and 422a. As a result, a gap is formed between the main outer clutch plate 31 and the main inner clutch plate 32 of the main clutch 3, and lubricating oil flows into this gap, and the connection state between the housing 20 and the inner shaft 23 is released. That is, the driving force transmission device 2 is inactivated.

(Operation and effect of the first embodiment)
According to the present embodiment described above, the following operations and effects can be obtained.

(1) In the driving force transmission device 2, the magnetic ring 6 is disposed between the front housing 21 and the pilot inner clutch plate 52 at a position facing the pilot outer clutch plate 51 in the axial direction. Thus, the magnetic path area in the magnetic path G is increased and the magnetic resistance is reduced as compared with the case where the magnetic ring 6 is not provided. Further, due to the expansion of the magnetic path area, magnetic saturation is suppressed even when a large current is passed through the electromagnetic coil 53. Thereby, the drive force which can be transmitted can be increased, suppressing the increase in the number of parts of the drive force transmission apparatus 2, and the assembly man-hour.

(2) Since a plurality of concave portions 60 that engage with the first inner peripheral spline projections 211 of the front housing 21 are formed in the circumferential direction on the outer peripheral portion of the magnetic ring 6, an arc formed between the concave portions 60. The portion 61 protrudes between two first inner peripheral spline protrusions 211 adjacent in the circumferential direction, and a gap between the outer peripheral surface 52c of the second inner clutch plate 51 and the inner peripheral surface 21d of the front housing 21 is appropriately set. Can be filled. Thereby, the magnetic path area in the magnetic path G can be increased as much as possible.

(3) The number of spline protrusions (first inner peripheral spline protrusions 211) of the front housing 21 that engage with the pilot outer clutch plate 51 and the magnetic ring 6 is the number of front sprockets that engage with the main outer clutch plate 31 of the main clutch 3. The number of spline protrusions (the first inner peripheral spline protrusion 211 and the second inner peripheral spline protrusion 212) of the housing 21 is smaller. That is, since the number of spline protrusions in the first region 210a of the inner peripheral spline part 210 is smaller than the number of spline protrusions in the second region 210b, the number of recesses 511 in the pilot outer clutch plate 51 and the recesses 60 in the magnetic ring 6 And the magnetic path area can be increased. Thereby, while further reducing the magnetic resistance in the pilot clutch part 7, magnetic saturation can be suppressed. Since the transmission torque in the electromagnetic clutch mechanism 5 is smaller than the transmission torque of the main clutch 3, there is no problem even if the number of spline protrusions in the second region 210b is reduced.

(4) Since the armature 50 is configured such that the thickness in the axial direction gradually decreases from the radially inner side toward the radially outer side, the armature 50 can be reduced in weight and the manufacturing cost can be reduced. be able to. In addition, since the distance between the axial end surface 500a of the armature 50 and the axial end surface 421b of the main cam 42 is configured to gradually increase from the radially inner side toward the radially outer side, the non-magnetic coil 53 is not. Even when the armature 50 moves to the main cam 42 side during energization, a gap can be formed between the axial end surface 500a of the armature 50 and the axial end surface 421b of the main cam 42. Thereby, when the electromagnetic coil 53 is energized, it is possible to suppress the armature 50 from being drawn toward the main cam 42 by the leakage magnetic flux. Therefore, the armature 50 can be reliably pulled toward the electromagnetic coil 53 when the electromagnetic coil 53 is energized.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 8 is a cross-sectional view showing a configuration example of the electromagnetic clutch 5A according to the second embodiment. The electromagnetic clutch 5A according to the present embodiment is substantially the same as the configuration of the electromagnetic clutch mechanism 5 according to the first embodiment, except that the outer housing 20A and the inner housing 23A are included in its configuration. Hereinafter, constituent elements having substantially the same functions as those described in the first embodiment are denoted by the same reference numerals, and redundant description thereof is omitted.

(Configuration of electromagnetic clutch 5A)
This electromagnetic clutch 5 </ b> A can transmit torque to the cylindrical rotating member 100 as the first member and the shaft-shaped rotating member 12 as the second member that can be relatively rotated on the same axis using the electromagnetic force generated in the electromagnetic coil 53. Used to connect to. In FIG. 8, the cylindrical rotating member 100 is indicated by a two-dot chain line.

  The electromagnetic clutch 5A includes a clutch portion 7A having an electromagnetic coil 53, an armature 50, an outer housing 20A, an inner housing 23A, an outer clutch plate 51A as a first clutch plate, and an inner clutch plate 52A as a second clutch plate. And a magnetic ring 6.

  The outer housing 20A includes a clutch case 21A that accommodates the clutch portion 7A with the inner housing 23A, and a coil housing 22A that is disposed between the electromagnetic coil 53 and the clutch portion 7A.

  The clutch case 21A is a member having a bottomed cylindrical shape, and is connected to the cylindrical rotating member 100 so as not to be relatively rotatable. Specifically, the clutch case 21 </ b> A is connected by a bolt 900 to a connecting member 24 that is spline-fitted to the cylindrical rotating member 100. Here, the clutch case 21A is an aspect of the “first member” of the present invention. The clutch case 21A is rotatably supported with respect to the inner housing 23A via a ball bearing 902.

  The coil housing 22A is fitted to the inner surface of the outer housing 20A on the opening side, and the coil housing 22A and the clutch case 21A are fixed so as not to rotate relative to each other by fixing means such as welding or screwing.

  The coil housing 22A includes an annular non-magnetic body 223A, a first magnetic body 221A as an outer magnetic body and a second magnetic body 222A as an inner magnetic body, which are arranged with the non-magnetic body 223A sandwiched in the radial direction. have. A bushing 901 is provided between the inner periphery of the second magnetic body 222A of the coil housing 22A and the outer periphery of the inner housing 23A to facilitate relative rotation between the coil housing 22A and the inner housing 23A.

  The electromagnetic coil 53 is accommodated in the coil housing 22A, is held by a coil holding portion 54 made of resin, and is rotatably supported with respect to the second magnetic body 222A of the coil housing 22A.

  The inner housing 23A is connected to the shaft-like rotating member 12 so as not to be relatively rotatable. Further, the inner housing 23 </ b> A is formed in a cylindrical shape and is disposed on the outer periphery of the shaft-like rotating member 12. Here, the inner housing 23A is an aspect of the “second member” of the present invention.

  The clutch portion 7A includes an outer clutch plate 51A that is spline-engaged with the clutch case 21A, and an inner clutch plate 52A that is spline-engaged with the inner housing 23A.

  A plurality of recesses 511A that engage with the inner peripheral spline protrusions 211A of the clutch case 21A are formed in the outer peripheral portion of the outer clutch plate 51A in the circumferential direction. Thereby, the outer clutch plate 51A is connected to the clutch case 21A so as to be rotatable relative to the clutch case 21A and movable in the axial direction.

  A plurality of protrusions 521A that contact the plurality of spline protrusions 231A formed on the outer periphery of the inner housing 23A in the circumferential direction are provided on the inner peripheral portion of the inner clutch plate 52A. Thereby, the inner clutch plate 52A is connected to the inner housing 23A so as not to be rotatable relative to the inner housing 23A and to be movable in the axial direction.

  The magnetic ring 6 has an annular plate shape having a predetermined thickness in the axial direction, and is made of, for example, a magnetic material such as iron. The magnetic ring 6 is disposed between the clutch case 21A and the inner clutch plate 52A and at a position facing the outer clutch plate 51A in the axial direction.

  Concave portions 60 that engage with the plurality of spline protrusions 211A of the clutch case 21A are formed on the outer peripheral portion of the magnetic ring 6. The inner peripheral surface 6b of the magnetic ring 6 faces the outer peripheral surface 52c of the inner clutch plate 52A via a gap. Thereby, the contact between the inner peripheral surface 6b of the magnetic ring 6 and the outer peripheral surface 52c of the inner clutch plate 52A is prevented, and the magnetic ring 6 does not hinder the rotation operation of the inner clutch plate 52A.

  When the electromagnetic coil 53 is energized, a magnetic flux is generated around the electromagnetic coil 53 and a magnetic path G is formed as shown in FIG. The magnetic flux path in the magnetic path is as follows: yoke 530 → first magnetic body 221A of coil housing 22A → clutch part 7A → armature 50 → clutch part 7A → second magnetic body 222A of coil housing 22A → yoke 530.

  When the magnetic path G is formed in the electromagnetic clutch 5A, the armature 50 is attracted toward the electromagnetic coil 53 in the axial direction, and the clutch portion 7 is pressed toward the electromagnetic coil 53 in the axial direction. Thereby, the plurality of outer clutch plates 51A and the plurality of inner clutch plates 52A are frictionally engaged, and the relative rotation between the clutch case 21A and the inner housing 23A is restricted. As described above, torque is transmitted from the cylindrical rotating member 100 to the shaft-shaped rotating member 12.

(Operation and effect of the second embodiment)
According to the present embodiment described above, the same operations and effects as those of the first embodiment can be obtained. In other words, the magnetic ring 6 is disposed between the clutch case 21A and the inner clutch plate 52A and is opposed to the outer clutch plate 51A in the axial direction, so that magnetic flux passes through the magnetic ring 6. Therefore, the magnetic path area in the magnetic path G is increased and the magnetic resistance is reduced as compared with the case where the magnetic ring 6 is not provided. Further, due to the expansion of the magnetic path area, magnetic saturation is suppressed even when a large current is passed through the electromagnetic coil 53. Thereby, the drive force which can be transmitted can be increased, suppressing the increase in the number of parts and assembly man-hours of the electromagnetic clutch 5A.

  Although the first embodiment and the second embodiment of the present invention have been described above, the present invention is not limited to these embodiments, and can be appropriately modified and implemented without departing from the spirit of the present invention. can do. For example, in the second embodiment, the magnetic ring 6 is disposed outside the inner clutch plate 52A, but may be disposed inside the outer clutch plate 51A.

DESCRIPTION OF SYMBOLS 1 ... Four-wheel drive vehicle, 2 ... Drive force transmission device, 3 ... Main clutch, 4 ... Cam mechanism, 5 ... Electromagnetic clutch mechanism, 5A ... Electromagnetic clutch, 6 ... Magnetic ring, 6a ... Axial end surface, 6b ... Inner circumference 7 ... Pilot clutch part, 7A ... Clutch part, 10 ... Control device, 11 ... O-ring, 11a ... Housing groove, 12 ... Shaft-shaped rotating member, 20 ... Housing, 20A ... Outer housing, 21 ... Front housing, 21A ... Clutch case, 21a ... Cylinder part, 21b ... Bottom part, 21c ... Female thread part, 21d ... Inner peripheral surface, 22 ... Rear housing, 22A ... Coil housing, 22a ... Accommodating space, 23 ... Inner shaft, 23A ... Inner housing, 23a ... Step surface 24 ... Connecting member 31 ... Main outer clutch plate 32 ... Main inner clutch plate 41 ... Pilot cam 41a ... cam groove, 42 ... main cam, 43 ... cam ball, 44 ... disc spring, 45 ... needle roller bearing, 50 ... armature, 51 ... pilot outer clutch plate, 51A ... outer clutch plate, 51a, 52a ... outer friction surface, 51b, 52b ... inner friction surface, 52 ... pilot inner clutch plate, 52c ... outer peripheral surface, 52A ... inner clutch plate, 53 ... electromagnetic coil, 54 ... coil holding portion, 60 ... recess, 61 ... arc portion, 62 ... connecting portion 81, 83 ... Ball bearings, 82 ... Needle roller bearings, 100 ... Cylindrical rotating member, 101 ... Car body, 102 ... Engine, 103 ... Transaxle, 104 ... Front wheel, 105 ... Rear wheel, 106 ... Rear differential carrier, 107 ... Propeller shaft, 108 ... Drive pinion shaft, 109 ... Front door Thru shaft 110 ... Rear differential 111 ... Rear axle shaft 210 ... Inner peripheral spline part 210a ... First region 210b ... Second region 211 ... First inner peripheral spline protrusion 211a ... End surface 212 ... Second Inner peripheral spline projection, 212a ... end face, 221 ... first annular member, 221a ... male screw part, 221b ... axial end face, 221A ... first magnetic body, 222 ... second annular member, 222A ... second magnetic body 223 ... third annular member, 223A ... non-magnetic material, 230 ... peripheral spline part, 231 ... peripheral spline protrusion, 231A ... spline protrusion, 232 ... spline fitting part, 311,321 ... protrusion, 322 ... oil hole, 411 ... Spline engaging part, 421 ... Pressing part, 421a ... Outer peripheral surface, 421b ... Axial end face, 421c ... Spline teeth, 422 ... Cam part, 422a ... Cam groove, 500a ... Axial end face, 501, 511, 511A ... Recess, 510, 520 ... Slit, 521, 521A ... Protrusion, 530 ... Yoke, 531 ... Electric wire, 900 ... Bolt, 901 ... Bush, 902 ... Ball bearing, G ... Magnetic path, O ... Rotation axis

Claims (5)

An inner rotating member and an outer rotating member that are relatively rotatable on the same axis; and
A main clutch that receives axial pressing force and connects the inner rotating member and the outer rotating member so as to transmit torque;
A first cam member and a second cam member are provided, and the first cam member is rotated relative to the second cam member to generate a pressing force for pressing the main clutch on the second cam member. A cam mechanism;
An electromagnetic clutch mechanism that operates the cam mechanism in response to the rotational force of the outer rotating member;
The electromagnetic clutch mechanism is
An electromagnetic coil that generates magnetic flux when energized,
An armature that moves in the axial direction by a magnetic force generated by energizing the electromagnetic coil;
An outer clutch plate engaged with a plurality of inner peripheral spline protrusions formed on the outer rotating member, and connected to the outer rotating member so as not to be relatively rotatable and axially movable;
An inner clutch plate that engages with a plurality of outer peripheral spline protrusions formed on the first cam member and is connected to the first cam member so as not to rotate relative to the first cam member and to be axially movable;
An annular magnetic body that is disposed between the outer rotating member and the inner clutch plate and is opposed to the outer clutch plate in the axial direction, and allows a magnetic flux generated by the electromagnetic coil to pass therethrough,
Driving force transmission device. The magnetic body has a recess formed on an outer peripheral portion thereof to engage with the inner peripheral spline protrusion of the outer rotating member.
The driving force transmission device according to claim 1. The main clutch is engaged with a plurality of spline protrusions formed on the outer rotating member, and is connected to the outer rotating member so as not to rotate relative to the outer rotating member and to be movable in the axial direction. An inner main clutch plate that engages with a plurality of spline protrusions formed on the member, and is connected to the inner rotating member so as not to be relatively rotatable and axially movable;
The number of spline protrusions of the outer rotating member engaged with the outer clutch plate of the electromagnetic clutch mechanism is less than the number of spline protrusions of the outer rotating member engaged with the outer main clutch plate of the main clutch.
The driving force transmission device according to claim 1 or 2. The armature has a thickness in the axial direction that gradually decreases from the radially inner side toward the radially outer side,
The driving force transmission device according to any one of claims 1 to 3. An electromagnetic clutch that couples a first member and a second member that are coaxially arranged so as to be rotatable relative to each other so as to transmit torque.
A first clutch plate engaged with a plurality of spline protrusions formed on the first member and connected to the first member so as not to be relatively rotatable and axially movable;
A second clutch plate engaged with a plurality of spline protrusions formed on the second member and connected to the second member so as not to rotate relative to the second member and to be movable in the axial direction;
An electromagnetic coil that generates magnetic flux when energized,
An armature that moves axially by the magnetic force generated by the magnetic flux;
An annular magnetic body that is disposed between the first member and the second clutch plate and is opposed to the first clutch plate in the axial direction, and allows the magnetic flux generated by the electromagnetic coil to pass therethrough;
Electromagnetic clutch.

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