JP5732892B2 - Electromagnetic engagement device - Google Patents

Description

  The present invention relates to an electromagnetic engagement device that displaces a pair of engagement members disposed on a common axis using an electromagnetic force between a release position and an engagement position.

  As an electromagnetic clutch, it has two return springs. When changing from the released state to the engaged state, the biasing force by one return spring is applied while the magnetic gap is larger than a predetermined value. There is known one that gives urging forces by two return springs (Patent Document 1). In addition, Patent Documents 2 and 3 exist as prior art documents related to the present invention.

JP 2010-7736 A JP 2010-71488 A JP 2009-138798 A

  The electromagnetic clutch of Patent Document 1 can be reliably released using the urging forces of the two return springs when released, but when engaged, it is necessary to increase the electromagnetic attractive force so as to overcome the two urging forces. There is a risk that power consumption will increase.

  Then, an object of this invention is to provide the electromagnetic engagement apparatus which can suppress the increase in power consumption.

In the electromagnetic engagement device of the present invention, the engagement surfaces are opposed to each other, and the relative movement is performed between a release position where the engagement surfaces are separated from each other and an engagement position where the engagement surfaces are engaged with each other. In a possible state, a pair of engaging members disposed on a common axis, a return spring that biases at least one of the pair of engaging members in a direction in which the engaging surfaces are separated from each other, and the release position An electromagnetic drive means for displacing the pair of engagement members against the biasing force of the return spring from the engagement position to the engagement position; and the engagement of one of the pair of engagement members An intermediate member that can be magnetized and is provided on the one engagement member in a state where it can protrude from the surface and is biased in a protruding direction, and the electromagnetic drive means includes the pair of engagement members and By forming a magnetic field on the intermediate member , Said intermediate member provided on the engaging member of the one, the it is possible to generate an electromagnetic force between the other one of the engagement members of the pair of engagement members in the release position, A gap formed between the intermediate member and the engagement surface of the other engagement member is set to be smaller than a gap formed between the engagement surfaces of the pair of engagement members. (Claim 1).

  According to this electromagnetic engagement device, since the gap between the engaging members that affects the electromagnetic attractive force is reduced by the intermediate member, the electromagnetic attractive force that can be generated with the same electric power is increased. Therefore, the electromagnetic attraction force for changing from the release position to the engagement position can be generated with low power consumption. Further, when changing from the engagement position to the release position, the urging force acting on the intermediate member can be used in addition to the urging force of the return spring, so that it can be surely released.

  In one aspect of the electromagnetic engagement device of the present invention, in the release position, a gap formed between the intermediate member and the engagement surface of the other engagement member is suppressed to a predetermined value or less. A regulating member for regulating the protruding amount of the intermediate member may be further provided. According to this aspect, the amount of protrusion of the intermediate member can be appropriately restricted by the restriction member, so that the gap between the intermediate member and the engagement surface can be prevented from becoming unnecessarily narrow. Therefore, in the case of using the oil while supplying oil between the pair of engaging members, drag resistance that can occur when the pair of engaging members are in the release position can be suppressed.

  In one aspect of the electromagnetic engagement device of the present invention, a groove extending in a radial direction about the axis may be formed in the intermediate member. According to this aspect, when the oil is used while being supplied between the pair of engaging members, the oil is discharged through the groove provided in the intermediate member, so that the oil stays in and around the intermediate member. Can be prevented. Thereby, drag resistance that can occur when the pair of engaging members is in the release position can be suppressed.

  In one aspect of the electromagnetic engagement device of the present invention, a friction coefficient of the intermediate member may be set to be smaller than a friction coefficient of the engagement surface. According to this aspect, it is possible to prevent a decrease in torque capacity associated with the sliding of the intermediate member.

  In one aspect of the electromagnetic engagement device of the present invention, the one engagement member may be fixed to a non-rotating element (Claim 5). Since one engaging member is fixed to the non-rotating element, the intermediate member provided on the engaging member does not rotate. Accordingly, since the influence of rotation on the intermediate member can be eliminated, it is possible to avoid a problem that the operation of the intermediate member is troubled by centrifugal hydraulic pressure or the like particularly when the oil is used while supplying oil between the pair of engaging members. it can.

  In one aspect of the electromagnetic engagement device of the present invention, the intermediate member may be provided on the one engagement member so as to be biased toward the outer peripheral side farther from the axis than the center near the axis ( Claim 6). When the engaging surfaces of the pair of engaging members come into contact with each other, the side closer to the axis is in contact more strongly than the far side. According to this aspect, since the contact on the side far from the axis can be supplemented by the intermediate member, the contact surface pressure distribution in the radial direction can be made uniform to prevent the torque capacity from being reduced, and the piece between the engagement surfaces can be prevented. You can also prevent hits.

  As described above, according to the electromagnetic engagement device of the present invention, the gap between the engaging members that affects the electromagnetic attractive force is reduced by the intermediate member, so that the electromagnetic attractive force that can be generated with the same electric power is large. Become. Therefore, the electromagnetic attraction force for changing from the release position to the engagement position can be generated with low power consumption.

The cross-sectional schematic diagram which showed a part of power transmission device with which the electromagnetic engagement apparatus which concerns on a 1st form was integrated. Explanatory drawing explaining the effect of the electromagnetic engagement apparatus of FIG. The figure which showed the state which looked at the intermediate member from the axial direction. The cross-sectional schematic diagram which showed a part of power transmission device with which the electromagnetic engagement apparatus which concerns on a 2nd form was integrated. The cross-sectional schematic diagram which showed a part of power transmission device with which the electromagnetic engagement apparatus which concerns on a 3rd form was integrated.

(First form)
FIG. 1 is a schematic cross-sectional view showing a part of a power transmission device incorporating an electromagnetic engagement device according to a first embodiment of the present invention. The power transmission device 1 is mounted and used in an automatic transmission of an automobile. The power transmission device 1 has a rotary shaft 2 extending in the direction of the axis Ax, and the rotary shaft 2 is supported by a case 3 as a non-rotating element via a bearing (not shown) in a state of being rotatable around the axis Ax. Has been. The electromagnetic engagement device 5 is mounted on the power transmission device 1 as a brake device for fixing the rotating shaft 2 to the case 3 and releasing the fixing.

  The electromagnetic engagement device 5 includes a cam mechanism 6 attached to the rotary shaft 2 and an electromagnetic drive unit 7 as an electromagnetic drive means disposed between the case 3 and the cam mechanism 6 and fixed to the case 3. I have. The cam mechanism 6 has a pair of cam members 8 and 9 combined with each other with the axis Ax as a common axis. A plurality (one in the figure) of cam balls 10 arranged in the circumferential direction are interposed between the pair of cam members 8 and 9, and the cam balls 10 are arranged in the circumferential direction formed on the cam members 8 and 9. It is held by a plurality of V-shaped grooves 11 and 12. Each V-shaped groove 11, 12 is formed in a V shape when each cam member 8, 9 is viewed from the outside in the radial direction, and is configured such that the depth gradually decreases in the rotational direction of the rotating shaft 2. Has been.

  As shown in FIG. 1, of the pair of cam members 8 and 9, the fixed cam member 8 positioned on the left side of the drawing is fixed on the rotating shaft 2 by a snap ring 14 and can rotate integrally with the rotating shaft 2. The other movable cam member 9 is combined with the fixed cam member 8 so as to be able to rotate relative to each of the counterpart fixed cam member 8 and the rotary shaft 2 and to move in the direction of the axis Ax. When the pair of cam members 8 and 9 change from a state in which the phases shown in FIG. 1 match to a state in which they are relatively rotated and shifted in phase, the cam ball 10 is moved to a V-shaped groove 11, along with the relative rotation. Therefore, the movable cam member 9 moves in a direction approaching the electromagnetic drive unit 7. In the electromagnetic engagement device 5, as a biasing unit that biases the movable cam member 9 in a direction approaching the fixed cam member 8 in order to suppress the relative rotation of the pair of cam members 8 and 9. A return spring 15 is provided. The return spring 15 is disposed on the outer periphery of the rotating shaft 2 in a state where movement in the right direction in the drawing is blocked by the snap ring 16.

  The electromagnetic drive unit 7 includes an electromagnetic coil 18 and a coil housing 19 that is fixed to the case 3 and holds the electromagnetic coil 18. When electric power is supplied to the electromagnetic coil 18, the electromagnetic drive unit 7 generates a magnetic field A as shown by a broken line in the figure to generate an electromagnetic force, and the electromagnetic movable member 9 that functions as an armature by the electromagnetic force. Attract. As a result, the movable cam member 9 is attracted toward the electromagnetic drive unit 7 against the urging force of the return spring 15, so that the relative rotation of the pair of cam members 8, 9 is promoted and the movable cam members 9 facing each other. The engagement surface 9a and the engagement surface 19a of the coil housing 19 are engaged with each other. Thus, the movable cam member 9 and the coil housing 19 can move between the release position where the engagement surfaces 9a and 19a are separated from each other and the engagement position where they are engaged with each other. The housing 19 corresponds to a pair of engaging members according to the present invention. When the movable cam member 9 and the coil housing 19 are engaged with each other, the rotation of the fixed cam member 8 combined with the movable cam member 9 is prevented. Fixed.

  The movable cam member 9 is provided with an intermediate mechanism 20 that first comes into contact with the engagement surface 19a of the coil housing 19 in the process of shifting from the release position to the engagement position. The intermediate mechanism 20 is opposed to the engagement surface 19a of the coil housing 19, and is capable of projecting and retracting with respect to the engagement surface 9a of the movable cam member 9, and the intermediate member 21 in the protruding direction (right of FIG. 1). And a spring 22 biased in the direction). The intermediate member 21 and the spring 22 are accommodated in an accommodation chamber 23 formed in the movable cam member 9. The amount of protrusion of the intermediate member 21 from the engagement surface 9a is set so that the gap G1 between the intermediate member 21 and the engagement surface 19a of the coil housing 19 is suppressed to a predetermined value or less. Specifically, the protruding amount of the intermediate member 21 is regulated by the protrusion 21 a of the intermediate member 21 abutting against a stopper 24 as a regulating member formed in the accommodation chamber 23. In the illustrated embodiment, the stopper 24 and the protrusion 21a are formed only on one side in the radial direction, but they may be formed on both sides in the radial direction. When formed on both sides in the radial direction, there is an advantage that the protrusion amount of the intermediate member 21 is more reliably regulated.

  As apparent from FIG. 1, in the release position, the gap G1 is set to be smaller than the gap G2 formed between the engagement surfaces 9a and 19a. FIG. 2 is an explanatory view for explaining the function and effect of the electromagnetic engagement device 5 and is shown side by side with a comparative example in which the intermediate mechanism 20 is omitted. As can be understood from FIG. 2, since the gap G1 is smaller than the gap G2 and the initial spring force (spring constant) can also be reduced, when the same power is supplied to each of the embodiment and the comparative example, the initial of the embodiment The suction force F0 is larger than that of the comparative example. Therefore, the electromagnetic attraction force for changing from the release position to the engagement position can be generated with low power consumption. In the case of the embodiment, the release force Ff when shifting from the engagement position to the release position is a resultant force of the spring force (biasing force) of the return spring 15 and the spring force (biasing force) of the spring 22. It becomes larger than the release force Ff of the example. Therefore, when changing from the engagement position to the release position, it is possible to release more reliably.

  As shown in FIG. 3, the intermediate member 21 is formed with a groove 25 extending in the radial direction about the axis Ax. Oil is supplied between the movable cam member 9 and the coil housing 19, but since the oil is discharged radially outward by the groove 25, the oil can be prevented from staying around the intermediate member 21 and its surroundings. Thereby, drag resistance that may occur at the release position can be suppressed. In addition, even if the intermediate member 21 is flat without forming such a groove 25, there is no problem in achieving the above-described effects.

  Moreover, although the friction coefficient of the part which contacts the engaging surface 19a among the intermediate members 21 may be set arbitrarily, especially the friction coefficient is set so that it may become smaller than the friction coefficient of the engaging surface 9a. And preferred. In this case, there is an advantage that it is possible to prevent a decrease in torque capacity accompanying the sliding of the intermediate member 21.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIG. Since this form corresponds to a modification of the first form, the same reference numerals are assigned to the same components in the first form as in FIG. In the electromagnetic engagement device 5 </ b> A of FIG. 4, the intermediate mechanism 20 is provided in the coil housing 19. Since the coil housing 19 is a non-rotating element, by providing the intermediate mechanism 20 there, the influence of rotation on the intermediate member 21 can be eliminated, so that oil is supplied between the movable cam member 9 and the coil housing 19. However, when used, it is possible to avoid a problem that a malfunction occurs in the operation of the intermediate member 21 due to centrifugal hydraulic pressure or the like.

(Third form)
Next, a third embodiment of the present invention will be described with reference to FIG. This form corresponds to a modification of the first form. Similarly to the above, the same reference numerals are attached to the same components as those in the first embodiment, and the overlapping description is omitted. Unlike the second embodiment shown in FIG. 4, the electromagnetic engagement device 5B shown in FIG. Is provided. According to this embodiment, the same effect as in the second embodiment can be achieved, and contact on the side far from the axis Ax can be supplemented by the intermediate member 21, so that the contact surface pressure distribution in the radial direction is made uniform. Thus, the torque capacity can be prevented from being reduced, and the contact between the engagement surfaces 9a and 19a can be prevented. This effect can also be achieved by providing the intermediate mechanism 20 on the movable cam member 9 so as to be biased toward the outer peripheral side in the same manner as described above.

  The present invention is not limited to the above embodiments, and can be implemented in various forms within the scope of the gist of the present invention. In each of the above embodiments, the electromagnetic engagement device of the present invention is used as a brake device, but the present invention can also be implemented as a clutch interposed between two rotating elements. Moreover, although the electromagnetic engagement device of each of the above forms includes a cam mechanism, the present invention can be implemented as a form having no cam mechanism.

3 Case (non-rotating element)
5, 5A, 5B Electromagnetic engagement device 7 Electromagnetic drive unit (electromagnetic drive means)
9 Movable cam member (engaging member)
9a Engagement surface 15 Return spring 19 Coil housing (engagement member)
19a Engagement surface 21 Intermediate member 24 Stopper (regulation member)
25 Groove Ax axis (common axis)
G1, G2 gap

Claims (6)

With the engagement surfaces facing each other, the engagement surfaces are movable relative to each other between a release position where the engagement surfaces are separated from each other and an engagement position where the engagement surfaces are engaged with each other. A pair of disposed engaging members;
A return spring that biases at least one of the pair of engagement members in a direction in which the engagement surfaces are separated from each other;
Electromagnetic drive means for displacing the pair of engagement members against the biasing force of the return spring from the release position to the engagement position;
An intermediate member that can be magnetized by being provided on the one engagement member in a state in which it can protrude from the engagement surface of one of the pair of engagement members and is urged in a protruding direction. And comprising
The electromagnetic drive unit forms a magnetic field on the pair of engagement members and the intermediate member, thereby to provide the intermediate member provided on the one engagement member and the other of the pair of engagement members. It is possible to generate an electromagnetic force between the engaging member,
In the release position, a gap formed between the intermediate member and the engagement surface of the other engagement member is smaller than a gap formed between the engagement surfaces of the pair of engagement members. Is set to be
An electromagnetic engagement device.   A regulating member that regulates a protruding amount of the intermediate member so that a gap formed between the intermediate member and the engaging surface of the other engaging member is suppressed to a predetermined value or less at the release position; The electromagnetic engagement device according to claim 1, further comprising:   3. The electromagnetic engagement device according to claim 1, wherein a groove extending in a radial direction about the axis is formed in the intermediate member.   The electromagnetic engagement device according to any one of claims 1 to 3, wherein a friction coefficient of the intermediate member is set to be smaller than a friction coefficient of the engagement surface.   The electromagnetic engagement device according to any one of claims 1 to 4, wherein the one engagement member is fixed to a non-rotating element.   The electromagnetic according to any one of claims 1 to 5, wherein the intermediate member is provided on the one engaging member so as to be biased toward an outer peripheral side farther from the axis than a center near the axis. Type engagement device.

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