JP2002221241A - Electromagnetic roller clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic roller clutch capable of maintaining a retainer in a neutral position in spite of rapid acceleration and deceleration. SOLUTION: The retainer 7 is assembled between an outward member 1 having a cylindrical surface 2 in the inner periphery and an inward member 4 having a cam surface 6 in the outer periphery, and a roller 9 is accommodated in a pocket 8 of the retainer 7. A switching spring 13 maintaining the retainer 7 in a neutral position is assembled between the retainer 7 and the inward member 4. A wave washer 27 is assembled between an electromagnet 22 and an armature 18, and the retainer 7 is pushed to a supporting plate 28 supported in the inward member 4 by the wave washer 27. When the inward member 4 is freely rotated so as to maintain the retainer 7 in a neutral position by means of the supporting plate 28 and frictional resistance operating on a contact point of the retainer 7 and the switching spring 13, the retainer 7 is prevented to relatively rotate to the inward member 4 even though the inward member 4 is rapidly accelerated and decelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a four-wheel drive vehicle (4
The present invention relates to an electromagnetic roller clutch that is incorporated in a drive path of a WD vehicle and transmits and interrupts a driving force according to a traveling state of the vehicle.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show an electromagnetic roller clutch which is incorporated in a drive path of a part-time 4WD vehicle and switches between two-wheel drive (2WD) and four-wheel drive (4WD) according to the running state of the vehicle. Are known from the prior art.

In this electromagnetic roller clutch, a cylindrical surface 51 is formed on an inner periphery of an outer member 50 as a driven side, and an input shaft 53 is rotatable by a bearing 52 incorporated in an end of the outer member 50. And a cam surface 55 that forms a wedge-shaped space between the inner member 54 and the cylindrical surface 51 is provided on the outer periphery of the inner member 54 that is spline-coupled to the input shaft 53. A pocket 57 is formed at a position facing the cam surface 55 in the retainer 56 incorporated in the
A roller 58 is accommodated in the pocket 57.

A first elastic member is provided between the retainer 56 and the inner member 54 for holding the retainer 56 at a neutral position where the roller 58 is not engaged with the cylindrical surface 51 and the cam surface 55. The switch spring 60 is provided.

The switch spring 60 is housed in a housing recess 63 formed on the end surface of the inner member 54, and a pair of engaging pieces 60 a provided at both ends of the switch spring 60 are attached to the peripheral wall of the housing recess 63. The retainer 56 is inserted into the notch 65 provided on the end face of the retainer 56 from the formed notch 64, and the retainer 56 is held at the neutral position by the elasticity of the switch spring 60.

A small-diameter shaft portion 54 is provided at an end of the inner member 54.
The armature 6 is provided with a detent ring 66 that is detented with respect to the retainer 56 on its small diameter shaft portion 54a.
7, the detent ring 66 is prevented from falling off by a retaining ring 68, and the armature 67 is slidably supported in the axial direction. The detent ring 66 is provided on the detent ring 66 in a hole 69 provided in the armature 67. The armature 67 is prevented from rotating with respect to the inner member 54 by engaging the projecting pieces 70.

Further, an electromagnet 71 for attracting the armature 67 is incorporated in the end of the outer member 50. Here, the electromagnet 71 includes a field core 72 around which a coil is wound and a rotor 73 made of a magnetic material. The field core 72 is fixed to the vehicle, while the rotor 73 is externally connected via a rotor holder 74. It is fixed to the direction member 50.

In the electromagnetic roller clutch having the above structure, the rotation transmitted from the transmission to the transfer is transmitted to the input shaft 53, and the rotation of the outer member 50 is incorporated between the axles of the driven wheels. Embedded.

When the retainer 56 is held at the neutral position by the elastic force of the switch spring 60 in the above-described assembly into the 4WD vehicle, the roller 58 is disengaged from the cylindrical surface 51 and the cam surface 55. In this position, the rotation of the input shaft 53 is not transmitted to the outer member 50, and the input shaft 53,
The inner member 54 and the retainer 56 rotate freely with respect to the outer member 50, and the 4WD vehicle runs in a two-wheel drive state.

In the running state, when the coil of the electromagnet 71 is energized, the armature 67 is attracted to the rotor 73, and the inner member 54 and the retainer 56 rotate relative to each other. And the cam surface 55.

For this reason, the rotation of the input shaft 53 is
And the 4WD vehicle is switched to a four-wheel drive state.

[0012]

By the way, in the above-mentioned electromagnetic roller clutch, the inner member 5 which rotates integrally with the input shaft 53 when the 4WD vehicle is driven by the two-wheel drive.
Since the rotation of 4 is transmitted to the retainer 56 via the switch spring 60, when the 4WD vehicle is rapidly accelerated by depressing the accelerator pedal or decelerated rapidly by depressing the brake pedal, the holding is performed. Vessel 5
Due to the inertial force of 6, the retainer 56 holding the inner member 54 and the roller 58 rotates relative to each other, and the roller 58 may engage the cylindrical surface 51 and the cam surface 55 to switch to the four-wheel drive state.

Here, when the 4WD vehicle switches from 2WD to 4WD due to rapid acceleration / deceleration, when the 4WD vehicle turns a sharp curve, a tight corner braking phenomenon occurs.
Running stability will be impaired.

In order to prevent this, the switch spring 6
It is necessary to increase the spring stiffness of 0, and if the spring stiffness is increased, the electromagnet 71 needs to attract the armature 67 against the elasticity of the switch spring 60. This necessitates its use, which is disadvantageous in terms of space and cost.

An object of the present invention is to provide an electromagnetic roller clutch capable of holding a retainer in a neutral position even when a 4WD vehicle is rapidly accelerated or decelerated in a two-wheel drive running state.

[0016]

In order to solve the above-mentioned problems, according to the present invention, a cylindrical surface is provided on one of an inner periphery of an outer member and an outer periphery of an inner member incorporated therein.
On the other hand, there is provided a cam surface which forms a wedge-shaped space in which the distance between the cylindrical surface and the both ends in the circumferential direction becomes narrower as it reaches both ends in the circumferential direction. A pocket is formed at a position opposed to the roller, and a roller that engages with the cam surface and the cylindrical surface by the relative rotation of the retainer and the member having the cam surface is stored in the pocket. A first elastic member for holding the retainer at a neutral position where the roller is disengaged from the cam surface and the cylindrical surface is incorporated between the members having side surfaces, and is provided on one end surface side of the retainer. A friction member fixed to a member having a cylindrical surface between the outer member and the inner member, the armature being detented with respect to the retainer, and movably supported in the axial direction. And an electromagnet for attracting the armature to the friction member. A second elastic member that presses the armature in a direction away from the friction member and presses the retainer in the axial direction via the armature. The member adopts a configuration in which a frictional resistance applying surface for applying rotational resistance to the retainer by receiving an axial pressing force applied to the retainer from the second elastic member is provided.

According to the above configuration, in the neutral state of the retainer, the retainer is pressed against the frictional resistance applying surface by the pressing of the second elastic member, and contacts the contact portion between the frictional resistance applying surface and the retainer. The retainer is held at the neutral position by the acting frictional resistance and the elastic force of the first elastic member.

Therefore, even if the 4WD vehicle is rapidly accelerated or decelerated in a two-wheel drive state, the retainer maintains the neutral position where the rollers are not engaged with the cylindrical surface and the cam surface, and the two-wheel drive to four-wheel drive , Can be reliably prevented from being switched.

Further, the first elastic member has a small elastic force as the first elastic member because the first elastic member holds the cage in the neutral position by the frictional resistance applying surface and the frictional resistance acting on the contact portion of the cage. Can be used.

For this reason, the electromagnet may be of such a small size that the armature can be attracted and held against the elastic force of the first elastic member and the second elastic member, and a small electromagnet is used. be able to.

Here, a wave washer is employed as a second elastic member for pressing the armature in a direction away from the friction member, and the wave washer is incorporated between the friction member and the armature to reduce the size of the electromagnetic roller clutch. Can be achieved.

Further, by making the friction coefficient between the frictional resistance applying surface and the retainer larger than the friction coefficient between the armature and the second elastic member, when the member having the cam surface is freely rotated, the armature and the second elastic member can rotate freely. Since the sliding can be caused at the contact portion of the second elastic member, the retainer can be more reliably held at the neutral position.

The frictional resistance applying surface may be formed directly on the member having the cam surface, or an annular support plate may be attached to the member having the cam surface, and the end surface of the retainer of the support plate may be formed with the annular support plate. The opposite side surface may be a friction resistance applying surface.

By forming the support plate from an elastomer, the coefficient of friction between the retainer and the support plate can be made larger than the coefficient of friction between the armature plate and the second elastic member. It can be prevented from moving in the circumferential direction with respect to the member having the surface.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 6 show a first embodiment of an electromagnetic roller clutch according to the present invention. As shown in FIGS. 1 and 2, the electromagnetic roller clutch has an outer member 1 similar to the conventional electromagnetic roller clutch shown in FIG. Are formed.

An inner member 4 is fitted to the input shaft 3 incorporated inside the outer member 1. Input shaft 3 and inner member 4
Are adapted to rotate integrally via a serration 5.

A cam surface 6 is formed on the outer periphery of the inner member 4 to form a wedge-shaped space in which the distance from the cylindrical surface 2 of the outer member 1 gradually decreases toward both ends in the circumferential direction.

A retainer 7 is incorporated between the outer member 1 and the inner member 4. A pocket 8 is formed in the retainer 7 at a position facing the cam surface 6, and a roller 9 is accommodated in the pocket 8. When the inner member 4 and the retainer 7 rotate relative to each other, the roller 9 engages with the cylindrical surface 2 and the cam surface 6 and rotates integrally with the input shaft 3 as shown in FIG. The rotation of the inner member 4 is transmitted to the outer member 1.

Further, between the retainer 7 and the inner member 4,
As shown in FIGS. 3 to 5, a switch spring 13 as a first elastic member for holding the retainer 7 at the neutral position is incorporated. The switch spring 13 has engaging pieces 13b facing outward in both ends of the arc-shaped portion 13a. The switch spring 13 is incorporated in a spring receiving recess 14 formed on one end surface of the inner member 4, and is formed on a notch 15 formed on a peripheral wall of the spring receiving recess 14 and one end of the retainer 7. A pair of engaging pieces 13b are inserted into the notch 16, and both ends of the notches 15, 16 in the circumferential direction are pressed by the engaging pieces 13b in the circumferential direction.

Here, the neutral position of the retainer 7 means that the roller 9 has the cylindrical surface 2 and the cam surface 6 as shown in FIG.
Refers to a position where it is not engaged.

As shown in FIG. 1, a small-diameter shaft 4a is provided at one end of the inner member 4, and a detent ring 17 and an armature 18 are fitted to the small-diameter shaft 4a.
The detent ring 17 is retained by a retaining ring 19. The detent ring 17 has a plurality of projections 20 on its outer periphery, and each projection 20 is fitted into a notch 16 provided on one end surface of the retainer 7, and the rotation prevents the detent ring 17 from being held. It is stopped by the container 7.

The armature 18 is slidably supported in the axial direction. A hole 21 is formed in the armature 18, and the armature 18 is prevented from rotating with respect to the holder 7 by the engagement of the protrusion 20 with the hole 21.

The armature 18 is attracted by an electromagnet 22 incorporated in one end of the outer member 1. Electromagnet 2
2 is a field core 24 around which a coil 23 is wound,
The field core 24 is mounted on the vehicle body when the electromagnetic roller clutch is mounted on the vehicle.

The rotor 25 is made of a magnetic material. The rotor 25 is fitted to a roller holder 26 made of a non-magnetic material,
On the other hand, the rotor holder 26 is fitted to the end of the outer member 1 and is prevented from rotating by the outer member 1.

Now, when the input shaft 3 rotates,
When the coil 23 is energized and the armature 1 is
When the suction holding of 8 is performed, the retainer 7 is prevented from rotating.
The inner member 4 that rotates integrally with the input shaft 3 rotates relative to the retainer 7, and the roller 9 engages with the cylindrical surface 2 and the cam surface 6 as shown in FIG. The rotation of the member 4 is transmitted to the outer member 1 via the roller 9.

When the inner member 4 and the retainer 7 rotate relative to each other, the notch 15 formed on the inner member 4 and the notch 16 provided on the retainer 7 are displaced in the circumferential direction. As a result, the switch spring 13 is elastically deformed. For this reason, when the energization of the coil 23 of the electromagnet 22 is cut off, the retainer 7 is returned to the neutral position by the restoring elasticity of the switch spring 13, and the engagement of the roller 9 with the cylindrical surface 2 and the cam surface 6 is released. The member 4 rotates freely with respect to the outer member 1.

Between the armature 18 and the rotor 25, a wave washer 27 as a second elastic member is incorporated. 6 (I) and (II) show a wave washer 27. The wave washer 27 presses the armature 18 in a direction in which the armature 18 moves away from the rotor 25, and the pressing force is smaller than the attraction force of the electromagnet 22. It has been. Also, the wave washer 27
Presses the retainer 7 via the armature 18, and the support plate 28 receiving the pressing force presses the inner member 4.
And is retained by a retaining ring 29.

The support plate 28 is made of a non-metal such as an elastomer, and the coefficient of friction between the contact portion of the support plate 28 and the holder 7 is determined by the armature 18 and the wave washer 27.
It is larger than the friction coefficient between them.

As described above, when the retainer 7 is pressed against the support plate 28 by the wave washer 27 incorporated between the rotor 25 and the armature 18, the frictional force applied to the contact portion between the retainer 7 and the support plate 28 is reduced. The retainer 7 can be held at the neutral position by the elasticity of the switch spring 13.

For this reason, the electromagnetic roller clutch has a 4WD
Even if the input shaft 3 is rapidly accelerated or decelerated in a running state in which the 4WD vehicle is driven by two wheels in a use state incorporated in the car,
The retainer 7 does not rotate relative to the inner member 4 and is always kept at the neutral position. Therefore, switching from two-wheel drive to four-wheel drive can be prevented.

The switch spring 13 is connected to the support plate 2.
Since the retainer 7 is held at the neutral position by the frictional resistance acting on the contact portion of the retainer 8 with the retainer 8, the switch spring 13 has such an elasticity that the retainer 7 in the engaged position can be returned to the neutral position. A small one is fine.

For this reason, the electromagnet 22 is connected to the switch spring 1.
3 and a small one having a capacity small enough to hold the armature 18 by suction against the elastic force of the wave washer 27 can be adopted.

When the inner member 4 and the retainer 7 rotate freely with respect to the outer member 1, the friction coefficient between the retainer 7 and the support plate 28 is smaller than the friction coefficient between the armature 18 and the wave washer 27. Since it is high, slippage occurs between the armature 18 and the wave washer 27, and the inner member 4 and the retainer 7 do not rotate relative to each other.

FIGS. 7 and 8 show a second embodiment of the electromagnetic roller clutch according to the present invention. In this embodiment, the outer member 30 is used as an input side, the inner member 31 is used as a driven side, a cylindrical surface 32 is formed on the outer periphery of the inner member 31, and a cam surface 33 is provided on the inner periphery of the outer member 30. ing.

The pocket 34a of the retainer 34 incorporated between the outer member 30 and the inner member 31 is
Relative to the cylindrical surface 32 and the cam surface 3
A roller 35 that engages with the roller 3 is incorporated.

Further, a switch spring 3 is provided inside the retainer 34.
6, the engagement pieces 36a provided at both ends of the switch spring 36 are combined with the notch 37 formed on one end surface of the retainer 34 and the notch 3 formed on the inner periphery of the outer member 30.
The retainer 34 is held at the neutral position by engaging with both circumferential ends of the retainer 8.

Further, the rotor 40 of the electromagnet 39 is fixed to the small-diameter shaft portion 31a of the inner member 31, and is prevented from rotating by the retainer 34 via the rotor 40 and the detent ring 41.
Armature 4 slidably supported in the axial direction
2, a wave washer 43 is mounted between the outer member 3 and the other end face of the retainer 34 by the wave washer 43.
0 against the frictional resistance applying surface 44 formed on the inner circumference of
The retainer 34 is held at the neutral position by the frictional resistance applied to the contact portion between the frictional resistance applying surface 44 and the retainer 34 and the elasticity of the switch spring 36.

Also in the above-described embodiment, the retainer 34 is held at the neutral position in a state where the outer member 30 rotates freely with respect to the inner member 31 even if the outer member 30 is rapidly accelerated or decelerated. be able to.

[0049]

As described above, according to the present invention, the frictional resistance applying surface is provided on the member having the cam surface, and the retainer is pressed against the frictional resistance applying surface to determine the frictional resistance acting on the contact portion. Since the retainer is held at the neutral position by the elastic force of the elastic member, the retainer is maintained at the neutral position even when the member having the cam surface is freely rotated when the member is rapidly accelerated or decelerated. Can be securely held, 4WD
It is possible to prevent the vehicle from being switched to four-wheel drive due to rapid acceleration / deceleration during traveling by two-wheel drive.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of an electromagnetic roller clutch according to the present invention;

FIG. 2I is a sectional view taken along the line II in FIG.
I) is a sectional view showing the engaged state of the roller shown in (I).

FIG. 3 is a cross-sectional view taken along a roll line in FIG. 1;

FIG. 4 is an exploded perspective view showing a part of the retainer, the detent ring, and the armature shown in FIG. 1;

FIG. 5 is a perspective view showing a part of the inner member shown in FIG. 1;

FIG. 6 (I) is a front view of the wave washer shown in FIG. 1, and (II) is a side view.

FIG. 7 is a sectional view showing a second embodiment of the electromagnetic roller clutch according to the present invention;

FIG. 8 is a sectional view taken along the line C-H of FIG. 7;

FIG. 9 is a longitudinal sectional front view showing a conventional electromagnetic roller clutch.

FIG. 10 is a cross-sectional view taken along the line II-II of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer member 2 Cylindrical surface 4 Inner member 6 Cam surface 7 Cage 8 Pocket 9 Roller 10 Restriction mechanism (Restriction means) 13 Switch spring (First elastic member) 18 Armature 22 Electromagnet 25 Rotor (Friction member) 27 Wave Washer (second elastic member) 28 support plate 30 outer member 31 inner member 32 cylindrical surface 33 cam surface 34 retainer 34a pocket 35 roller 36 switch spring (first elastic member) 39 electromagnet 40 rotor 42 armature 43 wave Washer (second elastic member) 44 Friction resistance applying surface

Claims (6)

[Claims] 1. A cylindrical surface is provided on one of an inner periphery of an outer member and an outer periphery of an inner member incorporated therein. A cam surface forming a narrowed wedge-shaped space is provided, and a pocket is formed at a position opposed to the cam surface on a retainer incorporated between an outer member and an inner member, and the retainer is formed in the pocket. And a roller that engages with the cam surface and the cylindrical surface by the relative rotation of the member having the cam surface, and the roller is disposed between the retainer and the member having the cam surface, between the cam surface and the cylindrical surface. The first for holding the retainer in the neutral position disengaged
The elastic member is incorporated, the armature provided on one end surface side of the retainer is prevented from rotating with respect to the retainer, and is supported movably in the axial direction, between the outer member and the inner member, In an electromagnetic roller clutch having a friction member fixed to a member having a cylindrical surface and incorporating an electromagnet for attracting the armature to the friction member, the armature is pressed in a direction away from the friction member. A second elastic member that presses the retainer in the axial direction through the armature, and a member on the side having the cam surface has an axial pressing force applied to the retainer from the second elastic member. An electromagnetic roller clutch having a frictional resistance applying surface for applying rotational resistance to a retainer in response to the rotation. 2. The electromagnetic roller clutch according to claim 1, wherein said second elastic member is provided between a friction member and an armature. 3. The electromagnetic roller clutch according to claim 2, wherein a friction coefficient between the frictional resistance applying surface and the retainer is larger than a friction coefficient between the armature and the second elastic member. 4. The electromagnetic roller clutch according to claim 1, wherein said frictional resistance applying surface comprises an annular support plate. 5. The electromagnetic roller clutch according to claim 4, wherein said support plate is made of a non-metallic material. 6. The electromagnetic roller clutch according to claim 5, wherein said non-metallic material comprises an elastomer.