JP2007002959A - Electromagnetic actuator, electromagnetic clutch using the electromagnetic actuator, and differential device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the power saving and durability of electromagnets, the easiness of layout by reducing the weight and size of the electromagnets, accurately detect the operating state of a differential limiting function, and to reduce the number of parts. <P>SOLUTION: This electromagnetic clutch comprises a differential mechanism 3, a clutch 5 operating to limit the differential movement of the differential mechanism 3, and the electromagnetic actuator 11 having the electromagnets 7 and plungers 9 axially receiving a movement operation force by the magnetic force thereof. The plungers 9 are limited to move in the axial direction, and the electromagnets 7 are disposed to be axially moved. The clutch 5 is operated by operating the plungers 9 by the energized electromagnets 7 to axially move the electromagnets 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic actuator, and an electromagnetic clutch and a differential device using the same.

  The differential device described in Patent Document 1 includes a differential mechanism, a dog clutch that locks the differential, an electromagnetic actuator that intermittently operates the dog clutch, and the like.

  The electromagnetic actuator includes an electromagnet and an armature, and the electromagnet is attached to a differential case containing a differential mechanism so as to be movable in the axial direction, and the armature is attached to a fixed side. When excited, the electromagnet moves under the reaction force of the magnetic force that attracts the armature and engages the dog clutch.

  Similarly, the differential device described in Patent Document 2 includes a differential mechanism, a dog clutch that locks the differential, an electromagnetic actuator that intermittently operates the dog clutch, a position switch that is disposed on the fixed side, and the like. It is configured.

This electromagnetic actuator is composed of an electromagnet arranged on the fixed side and a plunger that moves by its magnetic force. The plunger is clutched via a pressure plate fixed to a clutch ring that constitutes a part of the dog clutch. Move the ring and engage the dog clutch. The fixed position switch detects the moving position of the pressure plate while sliding in contact with the rotating pressure plate, and detects the dog clutch on / off state (operation state of the differential limiting function).
JP 2001-107983 A JP 2004-100924 A

  However, the differential device of Patent Document 1 has a problem in the use efficiency of the magnetic force of the electromagnet, and is difficult to save power and durability due to a large amount of excitation current (power consumption) and heat generation, and the use efficiency of the magnetic force. However, it is necessary to make the electromagnet larger in size, and the weight increases accordingly, and the layout on the vehicle deteriorates.

  In addition, the differential device of Patent Document 2 is configured to detect the position of the rotation-side pressure plate with a stationary-side position switch in order to detect the intermittent state of the dog clutch. If these wear, the position switch may malfunction. Further, although the pressure plate is press-fitted into the clutch ring, if deformation or collapse occurs during press-fitting, the position switch may also malfunction.

  Accordingly, the present invention provides an electromagnetic clutch that achieves the following object, and an electromagnetic actuator and a differential device using the same.

  The first purpose is to improve the power saving performance and durability of the electromagnet.

  The second purpose is to make the electromagnet light and small.

  A third object is to obtain excellent layout properties.

  The fourth object is to accurately detect the operating state of the differential limiting function.

  The first feature of the invention provides the following electromagnetic actuator. The electromagnetic actuator includes an electromagnet that is axially movable to actuate the clutch and limit the differential of the differential mechanism.

The electromagnetic actuator includes a plunger that is restricted from moving in the axial direction and is moved by the excited electromagnet to move the electromagnet in the axial direction.

  The second feature of the invention includes the following electromagnetic clutch. The electromagnetic clutch includes a clutch that operates to limit the differential of the differential mechanism. The electromagnetic clutch includes an electromagnetic actuator that controls the differential of the differential mechanism. The electromagnetic actuator includes an electromagnet that is movable in the axial direction to operate the clutch. The electromagnetic actuator includes a plunger that is limited in movement in the axial direction and is actuated by the excited electromagnet to move the electromagnet in the axial direction.

  A third aspect of the invention provides the following differential device. The differential device includes a differential mechanism. The differential device includes a clutch that operates to limit the differential of the differential mechanism. The differential device includes an electromagnetic actuator that controls the differential of the differential mechanism. The electromagnetic actuator includes an electromagnet that is movable in the axial direction to operate the clutch. The electromagnetic actuator includes a plunger that is limited in movement in the axial direction and is actuated by the excited electromagnet to move the electromagnet in the axial direction.

  According to the electromagnetic actuator, the electromagnetic clutch, and the differential device according to the features of the invention, the electromagnet is moved by the plunger that restricts the axial movement to operate the clutch, thereby limiting the differential of the differential mechanism.

  Therefore, for the differential device of Patent Document 1, the use efficiency of the magnetic force of the electromagnet is improved, the power saving performance and the durability are improved, the enlargement and weight increase of the electromagnet are prevented, and the layout is improved.

  In addition, for the differential device of Patent Document 2, it is possible to configure so as to detect the state of the operated device by the change in the axial position of the electromagnet arranged on the non-rotating side, and the state due to wear of the members Deterioration of detection function is prevented.

  The rear differential 1 (a differential apparatus according to an embodiment) will be described with reference to FIGS. In the following description, the left and right directions are the four-wheel drive vehicle using the rear differential 1 and the left and right directions in FIGS. 1 and 2.

  The features of the rear differential 1 will be described.

  The rear differential 1 includes a differential mechanism 3; a dog clutch 5 (clutch) for limiting the differential of the differential mechanism 3; an electromagnet 7; and an electromagnetic actuator 11 having a plunger 9 actuated by the excited electromagnet 7. including. The plunger 9 is restricted from moving in the axial direction. The electromagnet 7 is disposed so as to be movable in the axial direction. When the electromagnet 7 is excited, the plunger 9 is activated. The plunger 9 receives the reaction force, for example, moves the electromagnet 7 and operates the dog clutch 5.

  The differential mechanism 3 includes, for example, a differential case 13 (input member) as an input member that transmits drive torque input from a drive source of an engine or a motor to the differential mechanism 3.

  The differential mechanism 3 receives a driving torque and can rotate integrally with the differential case 13, and the first and second side gears 15 as relatively rotatable output members connected to the first and second output shafts. , 17.

  The dog clutch 5 can connect the differential case 13 and one of the side gears 15 and 17.

  The electromagnetic actuator 11 includes a position sensor 19 for detecting the axial displacement of the electromagnet 7 and determining the differential of the dog clutch 5.

The electromagnet 7 has a rotation preventing member 21 that restricts rotation while allowing movement in the axial direction,
The electromagnet 7 includes a holder 23 in which the plunger 9 is inserted.

The electromagnet 7 includes a stopper 69 that contacts the plunger 9.
A power system of a four-wheel drive vehicle using the rear differential 1 will be described.

  In this power system, the driving force of the engine is distributed from the transfer to the left and right rear wheels via the rear differential 1 (a differential device that distributes the driving force of the prime mover to the left and right rear wheels). When the 2-4 switching mechanism in the transfer and the left and right front wheel hub clutches are connected to each other, the driving force of the engine is transferred to the left and right front wheels via the front differential (a differential device that distributes the driving force of the prime mover to the left and right front wheels). The vehicle is allocated to a four-wheel drive state. When the 2-4 switching mechanism and the hub clutch are respectively disconnected, the vehicle enters a two-wheel drive state of rear wheel drive.

  The configuration of the rear differential 1 will be described.

  The rear differential 1 includes a bevel gear type differential mechanism 3, a dog clutch 5, an electromagnetic actuator 11, a differential case 13, a position switch 19 (position sensor), a return spring 25, a controller, and the like.

  The differential case 13 has a casing body 27 and a cover 29 fixed with bolts 31. The differential case 13 is disposed inside the carrier 33 and is supported by the carrier 33 through bearings 39 that receive thrust forces on the left and right boss portions 35 and 37. The carrier 33 defines an oil sump therein. The differential case 13 is rotationally driven by the driving force of the engine.

  The differential mechanism 3 includes a pinion shaft 41, a pinion gear 43 that is rotatably supported on the pinion shaft 41, and side gears 15 and 17. The side gears 15 and 17 mesh with the pinion gears 43 from the left and right. The end of the pinion shaft 41 engages with the through hole 45 of the casing body 27 and is prevented from being detached by a spring pin 47.

  The dog clutch 5 is configured by meshing teeth 49 formed on the right side gear 17 and meshing teeth 53 formed on the clutch ring 51. The clutch ring 51 is arranged so that the leg portion 55 engages with the through hole 57 of the casing body 27 and is prevented from rotating, and is movable in the axial direction. When the clutch ring 51 moves to the left as shown in FIG. 2, the dog clutch 5 is engaged and the differential of the differential mechanism 3 is locked. When the clutch ring 51 moves to the right as shown in FIG. 1, the engagement of the dog clutch 5 and the differential lock are released. The return spring 25 is disposed between the right side gear 17 and the clutch ring 51, and urges the clutch ring 51 toward the engagement release side (right side) of the dog clutch 5.

  The electromagnet 7 of the electromagnetic actuator 11 includes an electromagnetic coil 59 and left and right coil housings 61 and 63.

  The coil housings 61 and 63 are made of a magnetic material (carbon steel for mechanical structure; JIS G 4051-1979 S10C). The coil housings 61 and 63 are integrated by sandwiching the electromagnetic coil 59 from the left and right. The lead wire of the electromagnetic coil 59 is drawn out of the differential carrier 33 and connected to the on-vehicle battery. The left coil housing 61 has a guide member 65 made of a nonmagnetic material welded to a radially inner portion. The guide member 65 extends to the right in the axial direction. The left coil housing 61 and the guide member 65 constitute a holder 23 having a recess 24. The plunger 9 is inserted into the recess 24. The plunger 9 has a protrusion 9 a that protrudes in the axial direction from the end wall to the guide member 65. The protrusion 9 a prevents the plunger 9 and the guide member 65 from sticking. The plunger 9 has a guide member 67 made of a nonmagnetic material welded to the radially inner portion. The plunger 9 and the guide member 67 define a recess 26 therebetween. The plunger 9 is accommodated in the recess 24 of the holder 23 and is held so as to be relatively movable in the axial direction. The guide member 65 of the coil housing 61 is accommodated in the recess 26 between the plunger 9 and the guide member 67 and is held so as to be capable of relative movement in the axial direction. The right coil housing 63 has a stopper portion 69 that extends radially inward in order to prevent the plunger 9 from falling off. The stopper 69 abuts against the plunger 9 when the electromagnet 7 moves to the left as described below, and restricts the movement of the electromagnet 7 within an appropriate range.

  The outer periphery of the left coil housing 61 has a plurality of guide grooves 71 in the axial direction as shown in FIGS. The detent member 21 includes the same number of arm portions 73 as the guide grooves 71. The anti-rotation member 21 is fixed to the carrier 33, and the tips of the arm portions 73 are engaged with the guide grooves 71, respectively, to prevent the electromagnet 7 from being moved in the axial direction.

  The guide member 67 is sandwiched between the stepped portion 75 of the casing body 27 and the washer 77 in contact with the bearing 39 to restrict the movement of the plunger 9 in the axial direction. Therefore, the electromagnet 7 can also move in the axial direction with respect to the plunger 9.

  A stainless steel plate 79 shown in FIG. 4 is attached to the clutch ring 51 of the dog clutch 5 by press-fitting three legs 81. The coil housing 61 has an annular contact portion 83 that protrudes from the left side surface thereof to the plate 79.

  The probe 85 of the position switch 19 contacts the electromagnet 7 (clutch ring 63) by the pressing force of the built-in spring. As described below, the electromagnet 7 is intermittently engaged (0FF-ON) when the dog clutch 5 is engaged, and the differential lock state of the rear differential 1 is displayed on the driver's seat.

  Further, the leg portion 55 of the clutch ring 51 and the through hole 57 of the casing body 27 constitute a cam. When this cam receives a driving torque with the dog clutch 5 engaged, the cam thrust force is generated to urge the clutch ring 51 to engage the dog clutch 5.

  The coil housings 61 and 63 and the plunger 9 constitute a magnetic path P1 of the electromagnetic coil 59 (see FIG. 5), and the plunger 9 is an armature.

  The controller performs excitation and excitation stop of the electromagnetic coil 59.

When the electromagnetic coil 59 is energized, the plunger 9 receives a magnetic force and moves to the right, hits the washer 77, and stops. As shown in FIG. 2, the electromagnet 7 moves to the left by the reaction force (magnetic force) (reference arrow A). The annular contact portion 83 presses the plate 79 to move the clutch ring 51 to the left (reference arrow B). Thereby, the dog clutch 5 is engaged and the differential of the differential mechanism 3 is locked. Locking the differential in a situation where the left and right rear wheels are likely to run idle, such as when driving on rough roads, improves escape and driving performance on rough roads and prevents vehicle stacking.

  At this time, the cam is actuated to keep the dog clutch 5 engaged. Further, while the electromagnetic coil 59 is energized, leakage of the magnetic field lines is suppressed by the nonmagnetic material guide members 65 and 67 and the plate 79, and the use efficiency of the magnetic force is improved.

  When the excitation of the electromagnetic coil 59 is stopped, the return spring 25 returns the clutch ring 51 and the electromagnet 7 to the right by the urging force. As a result, the dog clutch 5 is disengaged, and the differential mechanism 3 is freely differential. Further, the annular contact portion 83 reduces the contact area between the coil housing 61 and the plate 79, suppresses the sticking of these, and makes the dog clutch 5 smoothly disengaged.

  The change in the differential lock state of the rear differential 1 is detected by the position switch 19 as described above and displayed on the driver's seat.

  The rear differential 1 has the following effects.

  Since the electromagnet 7 is moved by the reaction force received from the plunger 9 that restricts the movement in the axial direction and the dog clutch 5 is operated intermittently, the use efficiency of the magnetic force is improved, the power saving performance and the durability are improved, An increase in size and weight of the electromagnet 7 is prevented, and the layout is improved.

  Further, since the axial movement of the non-rotating electromagnet 7 can be detected by the position switch 19 and the state of the dog clutch 5 can be known, there is no sliding between the members accompanying the state detection unlike the conventional example. In addition to being freed from functional deterioration due to wear, the functional deterioration due to deformation or falling of the pressure plate used for state detection is also prevented.

  Further, since the pressure plate for detecting the state is not used, the number of parts is reduced accordingly.

  Further, since the rotation of the electromagnet 7 is prevented by the rotation preventing member 21, sliding and wear between the position switch 19 (probe 85) and the electromagnet 7 (coil housing 63) are prevented.

  Moreover, since the plunger 9 is supported by the holder 23 of the electromagnet 7, the unit property of the electromagnet 7 and the plunger 9 is improved.

  Other embodiments included in the scope of the present invention will be described.

  In the present invention, the position sensor may be a contact type or a non-contact type, and in the case of a contact type, it may be a push type or a pull type.

  The differential mechanism applicable to the differential device of the present invention is not limited to a bevel gear type differential mechanism, and may be a differential mechanism using another gear mechanism or a differential mechanism not using a gear mechanism.

  The clutch is not limited to one that locks the differential. For example, a differential limiting force may be continuously controlled using a friction clutch.

  Unlike the embodiment, the differential device of the present invention may be used as a front differential or a center differential instead of a rear differential.

It is sectional drawing of the rear differential of embodiment, and shows the state by which the differential lock | rock was cancelled | released. FIG. 2 is a cross-sectional view of the rear differential of FIG. 1 and shows a state where a differential is locked. It is sectional drawing which shows the rotation prevention mechanism of the electromagnet of FIG. It is a perspective view of the plate of FIG. It is an expanded sectional view of the electromagnetic actuator of FIG.

Explanation of symbols

1 Rear differential (differential device)
3 Differential mechanism 5 Dog clutch (clutch)
7 Electromagnet 9 Plunger 11 Electromagnetic Actuator 13 Differential Case (Input Member)
15, 17 Side gear (output member)
19 Position switch (position sensor)
21 Detent member 23 Holder

Claims (9)

An axially movable electromagnet to actuate the clutch and limit the differential of the differential mechanism;
An electromagnetic actuator including a plunger which is restricted by the axial movement and is actuated by the excited electromagnet to move the electromagnet in the axial direction.   The electromagnetic actuator according to claim 1, further comprising a position sensor that detects an axial displacement of the electromagnet in order to determine the operation of the clutch. A clutch that operates to limit the differential of the differential mechanism;
An electromagnetic actuator for controlling the differential of the differential mechanism,
The electromagnetic actuator is
An electromagnet that is axially movable to actuate the clutch;
An electromagnetic clutch including a plunger that is restricted from moving in the axial direction and that is actuated by the excited electromagnet to move the electromagnet in the axial direction. A differential device,
Differential mechanism;
A clutch that operates to limit the differential of the differential mechanism;
An electromagnetic actuator for controlling the operation of the differential mechanism,
The electromagnetic actuator is
An electromagnet that is axially movable to differentially engage the clutch;
A differential device including a plunger that is restricted from moving in the axial direction and that is actuated by the excited electromagnet to move the electromagnet in the axial direction. Including an input member rotatable by a drive source;
The differential mechanism includes first and second output members that are rotatable by the input member and are relatively rotatable connected to first and second output shafts,
The differential device according to claim 4, wherein the clutch is capable of connecting the input member and one of the first and second output members.   The differential device according to claim 4, wherein the electromagnet includes a rotation stopper that limits rotation while allowing movement in the axial direction.   The differential device according to claim 4, wherein the electromagnet includes a holder in which the plunger is inserted.   The differential device according to claim 4, wherein the electromagnet is centered by the plunger.   The differential device according to claim 4, wherein the electromagnet includes a stopper that contacts the plunger.

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