JP2007302056A - Rotation transmission device for four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small, compact and lightweigh rotation transmission device for a four-wheel drive vehicle with short axial length and a small number of part items. <P>SOLUTION: A cam face 8 is provided on an outer periphery of a large-diameter part 2 of a first shaft 1 of a rotation transmission device for a four-wheel drive vehicle, and a cylinder face 7 is formed on an inner periphery of an outer ring 3 provided outside the large-diameter part 2. A disc-like roller 11 assembled between the cylinder face 7 and the cam face 8 is housed in a radial groove 10 formed on a single face of an armature 9 made of a magnetic substance. A switch spring 13 is assembled between the armature 9 and the large-diameter part 2, so as to elastically hold the armature 9 in a neutral position where the roller 11 is disengaged. A rotor 18 is press-fit in an opening end of the outer ring 3, and an electromagnet 22 is opposed to the rotor 18. The armature 9 is adsorbed to the rotor 18 by energization to an electromagnetic coil 22a of the electromagnet 22, and the roller 11 is engaged with the cylinder face 7 and the cam face 8 by relative rotation of the armature 9 and a first shaft 1, so as to transmit the rotation of the first shaft 1 to the outer ring 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotation transmission device for a four-wheel drive vehicle that is interposed in a drive force transmission path of a four-wheel drive vehicle and switches between transmission and interruption of the drive force to a predetermined drive wheel.

  Referring to FIG. 5, the rear wheel propulsion shaft RS is generally connected from the transmission TM of the four-wheel drive vehicle, and the front wheel propulsion shaft is branched by the transfer TF on the front wheel drive path of the FR-based 4WD vehicle. Is equipped with a rotation transmission device A for a four-wheel drive vehicle that switches between transmission and interruption of driving force (Patent Document 1).

  A well-known structure of this type of rotation transmission device A for a four-wheel drive vehicle is provided with an outer ring that covers the large-diameter portion outside the input shaft having the large-diameter portion, and between the outer ring and the large-diameter portion. The two-way clutch is incorporated in the two-way clutch, and the on / off of the two-way clutch is controlled by an electromagnetic clutch.

  As an example of the structure of the two-way clutch, a cylindrical surface is formed on the inner periphery of the outer ring, and a cam surface is formed on the outer periphery of the large-diameter portion. The roller assembled between the cam surface and the cylindrical surface is held by a cage assembled between the outer ring and the large diameter portion, and the roller spring is applied to the cage by applying the force of the switch spring to the cage. The retainer is elastically held at a neutral position where the engagement with the cylindrical surface is released. An armature is attached to the end of the above-described cage so as not to rotate but to be movable in the axial direction.

  As an example of the structure of the electromagnetic clutch, an armature that is supported by a cage of a two-way clutch and supported so as to be movable in the axial direction, a rotor that is supported by an outer ring and that faces the armature in the axial direction, It consists of an electromagnet opposed to the rotor in the axial direction. The armature is attracted to the rotor by energizing the electromagnetic coil of the electromagnet, and the roller is cylindrically rotated by relatively rotating the input shaft and the cage by the frictional resistance acting on the attracting surface. Some of them are designed to be engaged with the surface and the cam surface.

  The above rotation transmission device measures the rotation speed of the front and rear wheels or the front and rear propulsion shafts of the vehicle with a sensor, and controls the current of the electromagnet according to the difference in the rotation speed or the change in the rotation speed.

  By mounting such a rotation transmission device on the driving force transmission path of the FR-based 4WD vehicle, when the rear wheel slips during acceleration, the rotation of the input shaft of the rotation transmission device increases accordingly. The engagement element engages, and torque is transmitted to the output shaft to obtain 4WD. In addition, when the vehicle turns, the front wheels (output shaft side) of the vehicle rotate rapidly. At this time, the engagement of the rotation transmission device is not engaged, the input shaft and the output shaft are idled, and tight corner braking occurs. Is prevented.

JP-A-10-59011

  By the way, as described above, the conventional rotation transmission device for a four-wheel drive vehicle has a mechanical type two-way clutch and an electromagnetic clutch for controlling on / off of the two-way clutch in the axial direction. Because of the many structures, the axial length of the rotation transmission device is long and heavy, and depending on the application, it may not be usable due to the size constraints described above. There are problems to be improved.

  If an attempt is made to simply reduce the size of the electromagnetic clutch, the torque transmission capability of the clutch will decrease due to a decrease in the effective radius of the clutch friction surface and a decrease in the armature attraction force due to a reduction in the space of the electromagnetic coil.

  In order to compensate for this decrease in transmission capacity, measures such as increasing the energization current to the electromagnetic coil are required. As a result, an increase in power consumption cannot be avoided, and the electromagnetic clutch can be downsized without increasing power consumption. It has become difficult to do.

  Therefore, the object of the present invention is to adopt a conventional clutch control system (switching on / off of energization to the electromagnetic coil) without changing it, and to achieve a small, compact and lightweight rotation with a short number of parts in the axial direction. By being a transmission device, the present invention is to provide a rotation transmission device for a four-wheel drive vehicle that is small in size and capable of suppressing power consumption.

  In order to solve the above-described problem, the driving force is transmitted to a predetermined driving wheel including a front wheel, a rear wheel, or four front and rear wheels of a four-wheel drive vehicle, and the driving force to the predetermined driving wheel is reduced. In the rotation transmission device for a four-wheel drive vehicle that switches between transmission and interruption, the rotation transmission device includes an inner member, an outer member provided outside the inner member, an inner periphery and an inner member of the outer member. An armature made of a magnetic material which is incorporated between the outer peripheries of the side members and movable in the axial direction, and is housed in a radial groove formed on one side surface of the armature, and the armature is composed of an inner member and an outer member. An engagement element coupled to one side and engaged with the outer circumference of the inner member and the inner circumference of the outer member at the time of relative rotation with respect to the other, and the engagement element is engaged with the outer circumference of the inner member and the inner circumference of the outer member. Armature in neutral position to be released A switch spring that holds elastically, a drop-off preventing means that prevents the engagement element from coming out of the radial groove of the armature in an axial direction, and an inner periphery of the outer member or an outer periphery of the inner member, A configuration is adopted which comprises a rotor facing the other side in the axial direction, and an electromagnet supported by a stationary member, facing the rotor in the axial direction, and attracting the armature to the rotor by energization.

  Here, the engagement element may be a roller or a sprag. When a roller is used as an engagement element, a cylindrical surface is formed on one of the inner periphery of the outer member and the outer periphery of the inner member, and a wedge-shaped space whose both ends in the circumferential direction are narrow between the cylindrical surface and the other. A cam surface to be formed is provided, and a roller is assembled between the cam surface and the cylindrical surface.

  On the other hand, when the sprag is used as an engagement element, a cylindrical surface is formed on the inner periphery of the outer member and the outer periphery of the inner member, and a sprag is assembled between the opposing cylindrical surfaces, and the armature that holds the sprag is set inside, Dividing outwardly, one split armature is fixed to the inner member or the outer member, and the elastic force of the switch spring is applied to the other split armature to hold it in the neutral position.

  Costs can be reduced by adopting a metal plate press-molded product or an aluminum or synthetic resin molded product as the engagement element.

  As a means for preventing the engagement element from coming off from the radial groove of the armature in the axial direction, it is attached to the outer periphery of the inner member, and between the armature and one side surface of the armature while being attracted to the rotor. It is possible to employ an annular stopper plate which is opposed to each other with an interval equal to or smaller than the thickness of the engaging element.

  In the rotation transmission device for a four-wheel drive vehicle according to the present invention, the outer member and the inner member may input rotational torque. For example, in the use of inputting rotational torque to the inner member, when the energization of the electromagnetic coil of the electromagnet is interrupted, the engaging element is engaged with the inner periphery of the outer member and the outer periphery of the inner member by the elastic force of the switch spring. Since it is held at the neutral position to be released, the rotational torque input to the inner member is not transmitted to the outer member, and only the inner member rotates freely.

  When the electromagnetic coil of the electromagnet is energized, the armature is attracted to the rotor. At this time, if the rotor is attached to the outer member, the armature and the engaging element held by the armature are connected to the outer member, and the inner member, the armature and the engaging element rotate relative to each other. The engaging element is pushed into the narrow portion of the wedge-shaped space and engages with the inner periphery of the outer member and the outer periphery of the inner member. By the engagement, the rotation of the inner member is transmitted to the outer member.

  On the other hand, when the rotor is attached to the inner member, the armature and the engagement element are connected to the inner member, and the outer member, the armature and the engagement element rotate relative to each other, and the relative rotation causes the engagement element to move in the wedge-shaped space. It is pushed into the narrow portion and engages with the outer periphery of the inner member and the inner periphery of the outer member. By the engagement, the rotation of the inner member is transmitted to the outer member.

  The switch spring is elastically deformed by the relative rotation of the armature with respect to the inner member or the outer member. For this reason, when the energization of the electromagnetic coil of the electromagnet is cut off, the restoring force of the switch spring returns to the neutral position where the armature and the engagement element are disengaged, and transmission of the rotational torque from the inner member to the outer member is cut off. Is done.

  Here, when the rotation transmission device is used under lubrication with oil, grease, etc., the viscosity of the lubricant interposed between the rotor and the armature may cause the armature to be held in the attracted state by the rotor, which may cause malfunction. There is. In order to prevent the occurrence of the malfunction, it is preferable to urge the armature in a direction away from the rotor by incorporating a separation spring between the opposed surfaces of the rotor and the armature. In this case, the axial length can be reduced by providing the rotor with a recess that accommodates a part of the separation spring.

  As described above, according to the present invention, the armature that holds the engagement member of the rotation transmission device and the rotor are disposed opposite to each other in the axial direction, and the electromagnet is disposed opposite to the rotor in the axial direction. Therefore, the rotation transmission device for a four-wheel drive vehicle using the same is reduced in size and weight, and power consumption is reduced. There is an advantage that becomes possible.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show a first embodiment of a rotation transmission device for a four-wheel drive vehicle according to the present invention.

  As shown in FIGS. 1 (I) and (II), a first shaft 1 as an inner member of a rotation transmission device for a four-wheel drive vehicle has a large diameter portion 2 at the shaft end portion. An outer ring 3 as an outer member is provided so as to cover the outer surface.

  The outer ring 3 has an end plate 4 on which a second shaft 5 is provided. The outer ring 3 is arranged coaxially with the first shaft 1, and the outer ring 3 and the first shaft 1 are relatively rotatable by a bearing 6 provided at the shaft end of the first shaft 1. .

  A cylindrical surface 7 is formed on the inner periphery of the outer ring 3. On the other hand, a narrow wedge-shaped space is formed on the outer periphery of the large-diameter portion 2 of the first shaft 1. A plurality of cam surfaces 8 are provided at equal intervals in the circumferential direction.

  An armature 9 is incorporated between the outer periphery of the large diameter portion 2 and the inner periphery of the outer ring 3. The armature 9 is made of a magnetic material, and a plurality of radial grooves 10 are formed at equal intervals on one side surface of the armature 9 facing the outer ring end plate 4. A roller 11 as an engaging member is provided in each radial groove 10. It is incorporated.

  The roller 11 has a disk shape. Since this roller 11 transmits a large rotational torque between the first shaft 1 and the outer ring 3 by engagement with the cylindrical surface 7 of the outer ring 3 and the cam surface 8 of the large diameter portion 2, it requires high hardness. It is preferably formed of a magnetic material such as iron.

  The large-diameter portion 2 has a spring housing recess 12 formed on one side surface of the first shaft 1 on the shaft end side, and a switch spring 13 is incorporated in the spring housing recess 12.

  The switch spring 13 has a C shape, and a pair of pressing pieces 13a are provided outward at both ends thereof. The pair of pressing pieces 13 a are inserted into a notch 15 provided in the armature 9 from a notch 14 formed in the peripheral wall of the spring housing recess 12, and end faces facing the notch 14 and the notch 15 in the circumferential direction. The armature 9 is elastically held at a neutral position where the roller 11 is disengaged from the cylindrical surface 7 and the cam surface 8 by the pressing.

  An annular stopper plate 16 is fitted to the shaft end portion of the first shaft 1, and the stopper plate 16 abuts on one side surface of the large-diameter portion 2 by a retaining ring 17 attached to the shaft end portion of the first shaft 1. It is held in the state to do. The stopper plate 16 closes the opening of the spring housing recess 12 and prevents the switch spring 13 from coming out of the opening of the spring housing recess 12. The stopper plate 16 is disposed at a position where a gap equal to or smaller than the thickness of the roller 11 is secured between the stopper plate 16 and the armature 9 in a state where the armature 9 is attracted to the rotor 18 to be described later. Is prevented from coming out. Further, the amount of separation of the armature 9 from the rotor 18 is limited.

  A rotor 18 made of a magnetic material is provided on the other side of the armature 9. The rotor 18 has cylindrical portions 18 a and 18 b facing in the same direction on the outer periphery and the inner periphery, and the outer cylindrical portion 18 a is press-fitted into the opening end portion of the outer ring 3 and integrated with the outer ring 3.

  Here, when the outer ring 3 is made of a magnetic material, a cylindrical rotor guide made of a non-magnetic material is connected to the opening end of the outer ring 3, and the outer cylindrical portion 18a of the rotor 18 is press-fitted into the rotor guide. Magnetic leakage from the rotor 18 to the outer ring 3 may be prevented.

  The inner cylindrical portion 18 b of the rotor 18 is rotatably supported by a bearing 19 provided outside the first shaft 1.

  An annular recess 20 is formed on the surface of the rotor 18 facing the armature 9, and a separation spring 21 incorporated in the recess 20 urges the armature 9 in a direction away from the rotor 18.

  An electromagnet 22 is incorporated between the outer cylindrical portion 18 a and the inner cylindrical portion 18 b of the rotor 18. The electromagnet 22 includes an electromagnetic coil 22a and a core 22b that supports the electromagnetic coil 22a. The core 22b is supported by a stationary member 23 and is fixedly arranged.

  The rotation transmission device shown in the first embodiment has the above-described structure. FIGS. 1 (I), (II) and FIG. 2 show a cut-off state of energization of the electromagnetic coil 22a of the electromagnet 22, and the armature 9 has a separating spring 21. Is separated from the rotor 18 by the pressing of. Further, the roller 11 is held in a neutral position where the engagement with the cylindrical surface 7 and the cam surface 8 is released by the elastic force of the switch spring 13.

  For this reason, even if rotational torque is input to the first shaft 1 and the first shaft 1 rotates, the rotation is not transmitted to the outer ring 3 and only the first shaft 1 rotates freely.

  As shown in FIG. 3, when the electromagnetic coil 22 a of the electromagnet 22 is energized in the rotation state of the first shaft 1, the magnet 22 is magnetized between the core 22 b, the rotor 18, and the armature 9 as indicated by a one-dot chain line in FIG. A circuit a is formed and the armature 9 is attracted to the rotor 18, and the armature 9 is coupled to the outer ring 3 through the rotor 18.

  For this reason, the first shaft 1 and the armature 9 rotate relative to each other, and the roller 11 engages with the cylindrical surface 7 of the outer ring 3 and the cam surface 8 of the large-diameter portion 2 as shown in FIG. Therefore, the rotation of the first shaft 1 is transmitted to the outer ring 3 via the roller 11, and the outer ring 3 rotates in the same direction as the first shaft 1.

  Further, when the first shaft 1 and the armature 9 are relatively rotated, the switch spring 13 is elastically deformed so as to narrow the interval between the pair of pressing pieces 13a. Therefore, when the energization of the electromagnet 22 to the electromagnetic coil 22a is cut off, the armature 9 is rotated by the restoring elasticity of the switch spring 13, and the roller 11 is placed on the cylindrical surface 7 and the cam surface 8 as shown in FIG. On the other hand, it is returned to the neutral position where the engagement is released, and the torque transmission from the first shaft 1 to the outer ring 3 is interrupted.

  As described above, in the rotation transmission device for a four-wheel drive vehicle shown in the first embodiment, the roller 11 can be engaged and disengaged by energizing and interrupting the electromagnetic coil 22a. Rotational torque can be transmitted to and cut off from the outer ring 3.

Further, since the armature 9 has a function of holding the roller 11, it is not necessary to provide a separate cage as in the conventional case, and the number of parts can be reduced, and the electromagnetic clutch of the conventional rotation transmission device can be reduced. In addition, since the two-way clutch roller 11 is built in, a small, compact and lightweight rotation transmission device having a short axial length can be obtained.
Thereby, it is possible to realize a rotation transmission device for a four-wheel drive vehicle that is small in size and can reduce power consumption.
As shown in FIG. 5, when the rotation transmission device A for a four-wheel drive vehicle is in use, the rotation transmission device A is assembled between a front differential FD of a FR-based 4WD vehicle, a front propeller shaft FP that connects the transmission TM and the transfer TF. The first shaft 1 may be directly connected to the transfer side, and the outer ring 3 may be directly connected to the front differential side.

  6 (I) and 6 (II) show a second embodiment of the rotation transmission device for a four-wheel drive vehicle according to the present invention. In this embodiment, a cam surface 24 is provided on the inner periphery of the outer ring 3, and a cylindrical surface 25 is formed on the outer periphery of the large diameter portion 2. In this case, the inner cylindrical portion 18 b of the rotor 18 is press-fitted into the first shaft 1, the rotor 18 is fixed to the first shaft 1, and the outer cylindrical portion 18 a of the rotor 18 is incorporated into the opening end of the outer ring 3. The bearing 26 is rotatably supported.

  Further, the switch spring 13 is accommodated in an annular groove 12 ′ formed on the surface of the armature 9 facing the rotor 18, and a pair of pressing pieces 13 a provided at both ends of the switch spring 13 are cut off on the armature 9. The roller 11 is inserted into the notch portion 28 formed on the inner periphery of the outer ring 3 from the notch 27 and the opposite end surfaces in the circumferential direction of the notch 27 and the notch portion 28 are pressed in opposite directions, and the roller 11 is thereby pressed. The armature 9 is elastically held in a neutral position where the engagement with the cam surface 24 and the cylindrical surface 25 is released.

Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.
Moreover, since an effect | action and an effect are the same as 1st Embodiment, description is abbreviate | omitted.
FIGS. 7 (I) and (II) show a third embodiment of the rotation transmission device for a four-wheel drive vehicle according to the present invention. In the third embodiment, the outer periphery of the large-diameter portion 2 and the inner periphery of the outer ring 3 are cylindrical surfaces 29, 30, and a sprag 31 as an engagement element is incorporated between the cylindrical surfaces 29, 30.

  Here, the sprag 31 is made of a plate, has a low height in the standing state, and gradually increases in height by rotating around the center of gravity, and arc-shaped surfaces 31 a and 31 b provided at both ends are formed on the cylindrical surfaces 29 and 30. It is designed to engage. In addition, the arcuate surfaces 31 a and 31 b at both ends in the standing state are in a neutral position where they are not engaged with the cylindrical surfaces 29 and 30.

  Further, the armature 9 is divided into two divided armatures 9a and 9b having different diameters, and the divided armature 9b on the small diameter side is fixed to the large diameter portion 2, and the large diameter side of the divided armature 9b on the small diameter side is fixed. The split armature 9a is rotatable.

  Further, the pressing pieces 13a at both ends of the switch spring 13 are inserted from the notches 32 formed in the small-diameter split armature 9b into the notches 33 provided in the large-diameter split armature 9a. The end surfaces facing each other in the circumferential direction of the portion 33 are pressed in opposite directions, and the split armature 9a on the large-diameter side is elastically held in a neutral position where the sprag 31 is disengaged from the cylindrical surfaces 29 and 30 by the pressing. ing.

Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.
In the rotation transmission device shown in the third embodiment, the neutral position where the sprag 31 is disengaged from the cylindrical surfaces 29 and 30 as shown in FIG. Is held in. For this reason, even if rotational torque is input to the first shaft 1 and rotates, the rotation is not transmitted to the outer ring 3 and the first shaft 1 rotates freely.

  When the first shaft 1 rotates in the direction indicated by the arrow in FIG. 7 (II), when the electromagnetic coil 22a is energized, the large-diameter-side divided armature 9a is attracted to the rotor 18 and fixed to the first shaft 1. The split armature 9b on the small diameter side and the split armature 9a on the large diameter side rotate relative to each other, and the sprag 31 rotates and tilts around the center of gravity by the relative rotation, and the arcuate surfaces 31a and 31b at both ends are cylindrical as shown in FIG. Engage with surfaces 29, 30. Due to the engagement, the rotation of the first shaft 1 is transmitted to the outer ring 3 via the sprag 31, and the outer ring 3 rotates in the same direction as the first shaft 1.

  Further, the switch spring 13 is elastically deformed by the relative rotation of the small-diameter divided armature 9b and the large-diameter divided armature 9a. For this reason, when the energization to the electromagnetic coil 22a is cut off, the split armature 9a on the large diameter side is rotated by the restoring elasticity of the switch spring 13, and the sprag 31 is moved relative to the cylindrical surfaces 29 and 30 as shown in FIG. Returning to the neutral position where the engagement is released, the transmission of the rotational torque from the first shaft 1 to the outer ring 3 is interrupted.

  Also in the third embodiment, as in the first embodiment, a small, compact and lightweight rotation transmission device having a short axial length can be obtained.

In the third embodiment, the same effect can be obtained even when the large-diameter-side split armature 9a is fixed to the outer ring 3, the small-diameter-side split armature 9b is rotatable and the switch spring 13 is locked. In that case, the rotor 18 is fixed to the first shaft 1.

(I) is a longitudinal front view showing a first embodiment of a rotation transmission device for a four-wheel drive vehicle according to the present invention, and (II) is a sectional view taken along the line II of (I). Sectional drawing which expands and shows the rotor site | part of FIG. 1 (I) Sectional drawing which shows the adsorption | suction state of the armature with respect to the rotor of the rotation transmission apparatus for four-wheel drive vehicles shown in FIG. 1 is a longitudinal side view showing an engagement state of rollers of the rotation transmission device for a four-wheel drive vehicle shown in FIG. Explanatory drawing which shows the use condition of the rotation transmission apparatus for four-wheel drive vehicles of embodiment (I) is a longitudinal front view showing a second embodiment of the rotation transmission device for a four-wheel drive vehicle according to the present invention, and (II) is a cross-sectional view taken along the roll line of (I). (I) is a longitudinal front view showing a third embodiment of the rotation transmission device for a four-wheel drive vehicle according to the present invention, and (II) is a cross-sectional view taken along the line ha of (I). FIG. 7 is a longitudinal sectional view showing an engaged state of a sprag of the rotation transmission device for a four-wheel drive vehicle shown in FIG.

Explanation of symbols

1 First shaft (inner member)
3 Outer ring (outer member)
7 Cylindrical surface
8 Cam surface 9 Armature 9a Large diameter split armature 9b Small diameter split armature 10 Radial groove 11 Roller (engagement element)
13 Switch spring 18 Rotor 20 Recess 21 Separation spring 22 Electromagnet 22a Electromagnetic coil 23 Stationary member 24 Cam surface 25 Cylindrical surface 29 Cylindrical surface 30 Cylindrical surface 31 Sprag (engagement element)
A Four-wheel drive vehicle rotation transmission device FD Front differential TM Transmission TF Transfer FP Front propeller shaft RS Rear wheel propulsion shaft

Claims (6)

A four-wheel drive vehicle that is interposed in a drive force transmission path that transmits a drive force to a predetermined drive wheel consisting of front wheels, rear wheels, or front and rear four wheels of a four-wheel drive vehicle, and switches between transmission and interruption of the drive force to the predetermined drive wheel. Rotation transmission device for
The rotation transmission device is incorporated between the inner member, the outer member provided outside the inner member, the inner periphery of the outer member and the outer periphery of the inner member, and is movable in the axial direction. An armature made of a magnetic material and housed in a radial groove formed on one side surface of the armature. The armature is coupled to one of the inner member and the outer member, and the outer periphery of the inner member is relatively rotated with respect to the other. And an engaging member that engages with the inner periphery of the outer member, and a switch spring that elastically holds the armature in a neutral position where the engaging member is disengaged from the outer periphery of the inner member and the inner periphery of the outer member. A drop-off preventing means for preventing the engaging element from coming out of the radial groove of the armature in the axial direction; and an inner circumference of the outer member or an outer circumference of the inner member and being fixed to the other side surface of the armature in the axial direction. Opposing rotor and stationary Is supported by the timber opposed to each other in the rotor in the axial direction, the rotation transmission device for four-wheel drive vehicle, which is a rotation transmission device comprising a magnet for attracting the armature to the rotor by energizing.   A cylindrical surface is formed on one of the outer periphery of the inner member and the inner periphery of the outer member, and a cam surface is formed on the other side to form a narrow wedge-shaped space between both ends of the cylindrical surface. The rotation transmission device for a four-wheel drive vehicle according to claim 1, wherein an engagement member engaged with and disengaged from the cam surface and the cylindrical surface is a roller.   A cylindrical surface is formed on each of the outer periphery of the inner member and the inner periphery of the outer member, and an engaging member that engages and disengages from both cylindrical surfaces is a sprag, and the armature is moved in and out. The split armature is divided into two parts, one split armature is fixed to the inner member or the outer member, and the elastic force of the switch spring is applied to the other split armature to disengage the sprag in the neutral position where it is disengaged from the cylindrical surface. The rotation transmission device for a four-wheel drive vehicle according to claim 1 held.   The rotation transmission device for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein the engagement element is formed of a press-molded product.   The rotation transmission device for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein the engagement element is made of a molded product of aluminum or synthetic resin.   The rotation transmission device for a four-wheel drive vehicle according to any one of claims 1 to 5, further comprising a separation spring that urges the armature in a direction away from the rotor.

Images