JP2005168191A - Electromagnetic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To hold the position of a plunger by a remaining magnetism. <P>SOLUTION: The electromagnetic actuator comprises a coil housing 67 which holds an electromagnetic coil 65 to constitute a part of a magnetic path, and a plunger 71 which constitutes the magnetic path of the electromagnetic coil 65 along with the coil housing 67 and is excited when the electromagnetic coil 65 is energized to move to the position for operating a device 9 to be operated. Since the plunger 71 is made of such a magnetic material that has appropriate remaining magnetism characteristics, the plunger 71 is held at the operation position for the device 9 operated even when the energizing of the electromagnetic coil 65 is stopped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic actuator that operates a clutch device (operated device) with a power transmission device of a vehicle, for example.

  Patent Document 1 discloses an actuator 501 as shown in FIG. 12 and a differential device 503 using the actuator 501.

  The differential device 503 includes an actuator 501, an outer differential case 505, an inner differential case 509 to which a bevel gear type differential mechanism 507 is connected, a dog clutch 511 (operated device) that intermittently connects the outer differential case 505 and the inner differential case 509, and the like. It is composed of

  The actuator 501 includes an electromagnetic coil 513, a coil housing 515, a permanent magnet plunger 517, a return spring 519, and the like. When the electromagnetic coil 513 is energized, the excited plunger 517 moves to engage the dog clutch 511. The driving force of the engine is transmitted from the outer differential case 505 to the differential mechanism 507 via the inner differential case 509 and distributed to the left and right wheels.

In the actuator (electromagnetic actuator) configured as described above, the plunger is generally made of a soft magnetic material having a small residual magnetism.
JP2003-158862A (FIG. 1)

  In the case of an electromagnetic actuator where the plunger is made of a soft magnetic material with a small residual magnetism, it is necessary to continue energizing the electromagnetic coil in order to keep the operated device in the operating state with the plunger. Although the control is performed, it can still be used only by a device that allows a certain amount of power consumption. For example, a vehicle-mounted device has a heavy battery load, and the fuel consumption of the engine decreases.

  Further, since heat is generated by continuously energizing the electromagnetic coil, it is necessary to select oil or electromagnetic coil having excellent heat resistance, and the cost increases accordingly.

  Further, since the operated device is configured to return to the opposite state by the spring (biasing member) when the energization of the electromagnetic coil is stopped, when the electromagnetic coil malfunctions, it is held by the magnetic force of the electromagnet. Can not hold.

  Soft magnetic materials are expensive and have poor processability.

  However, in an apparatus using a permanent magnet for the plunger, such as the actuator 501 in FIG. 12, the position of the plunger (the state of the operated device) is maintained by its own magnetic force even when the energization of the electromagnetic coil is stopped. Thus, the power consumption for maintaining the state of the operated device and the burden on the battery are reduced, the fuel consumption of the engine is improved, and there is no need to use a soft magnetic material for the plunger.

  However, it is conceivable that magnetic metal contamination (abrasion powder) is attracted to the permanent magnet plunger and clogs the gap, resulting in movement resistance. In this case, the electromagnetic actuator is complex so that it does not malfunction. Forced to deal with it.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electromagnetic actuator that prevents power consumption and an increase in battery load, prevents contamination from being attracted by a plunger, and maintains normal operation over a long period of time.

  The electromagnetic actuator according to claim 1 holds an electromagnetic coil, forms a magnetic path of the electromagnetic coil together with the coil housing that forms a part of the magnetic path, and is excited when the electromagnetic coil is energized, An electromagnetic actuator including a plunger that moves toward an operation position of an operated device, wherein at least one of members constituting the magnetic path is made of a magnetic material having appropriate residual magnetic characteristics, and the electromagnetic coil is energized Even when the operation is stopped, the plunger is held on the operation position side of the operated device.

  A second aspect of the present invention is the electromagnetic actuator according to the first aspect, wherein a sensor for detecting a state of the operated device is provided, and the indication that the operated device deviates from an operation state by the plunger is provided. When detected by the sensor, the electromagnetic coil is energized to compensate for a decrease in residual magnetism of the plunger, thereby preventing deviation from the operating state of the operated device.

  A third aspect of the present invention is the electromagnetic actuator according to the first or second aspect, wherein the stopper is positioned against the coil housing against the plunger moved to the operation position side of the operated device. And having a smooth contact surface between the stopper portion and the plunger.

  A fourth aspect of the present invention is the electromagnetic actuator according to any one of the first to third aspects, wherein the electromagnetic coil is energized to resist the urging force of the urging member. The plunger is operated in the direction, the residual magnetism of the plunger is demagnetized by the electromagnetic coil, and the plunger is operated in the other direction by the biasing force of the biasing member.

  A fifth aspect of the present invention is the electromagnetic actuator according to the fourth aspect, characterized in that the direction of movement of the plunger and the direction of the urging force of the urging member are the same.

  According to the electromagnetic actuator of the present invention, as in the configuration of claim 1, at least one of the members constituting the magnetic path of the electromagnetic coil is made of a magnetic material having an appropriate residual magnetic characteristic, thereby energizing the electromagnetic coil. Even when stopped, the plunger is held on the operated position of the operated device (for example, the coupling position or the releasing position of the clutch device), so the power consumption and the battery burden for maintaining the status of the operated device are significant. In addition to improving the fuel efficiency of the engine, it is no longer necessary to use an expensive soft magnetic material with poor processability for the plunger.

  In addition, examples of magnetic materials having appropriate residual magnetic properties include carbon steel for mechanical structures (for example, material of about S45C). Since this material is excellent in workability (machinability), the processing cost is reduced. It can be reduced accordingly.

  In the electromagnetic actuator of the present invention, the appropriate residual magnetism applied to the plunger is the minimum magnetic force (residual magnetism) necessary for maintaining the position, which is smaller than the magnetic force (residual magnetism) of the permanent magnet, When the plunger is moved, the magnet is gradually attenuated and the plunger is demagnetized by the electromagnetic coil. Therefore, the amount of contamination adsorbed by the residual magnetism of the plunger is substantially small, and therefore the operation of the electromagnetic actuator is prolonged. Stays normal.

  The electromagnetic actuator of claim 2 can achieve the same effect as that of the invention of claim 1.

  In addition, since the operated device detects signs of deviating from the operation state by the plunger and the magnet is re-magnetized by the electromagnetic coil to compensate for the residual magnetism, the power consumption of the electromagnetic coil is kept low while keeping the power consumption of the electromagnetic coil low. The operating device can be held in the intended operating state.

  The electromagnetic actuator of claim 3 can obtain the same effect as that of the invention of claim 1 or claim 2.

  Also, by smoothing the contact surface between the stopper portion of the coil housing and the plunger (for example, processing with increased flatness), the magnetic resistance at this contact surface is reduced and a magnetic path is established. The suction force of the plunger due to the magnetic force is enhanced, and an attractive force is generated between the smooth surfaces. Therefore, a large attractive force acts on the plunger on the contact surface with the coil housing, and the operated device by the plunger The operation function and the state holding function are further improved.

  The electromagnetic actuator according to claim 4 can achieve the same effects as the inventions according to claims 1 to 3.

  Further, in this configuration in which the plunger is moved in the opposite direction by the biasing member after demagnetizing the residual magnetism of the plunger with the electromagnetic coil, the plunger can be moved without specially strengthening the biasing member. The increase in size of the electromagnetic coil and the increase in power consumption and battery burden accompanying the strengthening of the urging member are prevented, and the amount of contamination adsorbed by the plunger is greatly reduced, so that the operation can be maintained normally for a long time.

  The electromagnetic actuator of claim 5 can achieve the same effect as that of the invention of claim 4.

  In addition, since the direction of movement of the plunger and the direction of the urging force of the urging member are the same, the plunger is prevented from falling and galling due to the tumbling when being moved by being pressed by the urging force of the urging member. Since it moves smoothly, the operation of the electromagnetic actuator is kept normal.

  Next, an embodiment of the present invention will be described.

(Embodiment)
The electromagnetic actuator 1 which is one embodiment of the present invention and the differential device 3 using the same will be described with reference to FIGS. 8 shows graphs of the energizing current value and direction of the electromagnetic coil 65 and the residual magnetism of the plunger 71. FIG. 9 shows a graph of the energizing current value of the electromagnetic coil 65 and the thrust (thrust force) of the plunger 71. 10 shows graphs of the energization current value of the electromagnetic coil 65 and the residual magnetism of the plunger 71, and FIG. 11 shows graphs of the residual magnetism and the sticking force of the plunger 71. In the following description, the left and right directions are left and right directions in a vehicle in which the differential device 3 is used.

[Configuration of electromagnetic actuator 1]
The electromagnetic actuator 1 holds an electromagnetic coil 65 and forms a magnetic path of the electromagnetic coil 65 together with a coil housing 67 that constitutes a part of the magnetic path, and is energized and energized when the electromagnetic coil 65 is energized. An electromagnetic actuator including a plunger 71 that moves toward a position where the clutch 9 (operated device) meshes, and the plunger 71 (at least one of the members constituting the magnetic path) has a magnetism having an appropriate residual magnetic characteristic. Due to the material, even when the energization of the electromagnetic coil 65 is stopped, the plunger 71 is held by the residual magnetism on the engagement position (operation position) side of the dog clutch 9.

  The differential device 3 includes an electromagnetic actuator 1, a differential case 5, a bevel gear type differential mechanism 7, a dog clutch 9 (operated device), a return spring 11 (biasing member), a controller, and the like. Yes.

  The differential case 5 includes a casing body 15 and a left cover 17, and the casing body 15 and the cover 17 are fixed with bolts 19. The differential case 5 is disposed inside the differential carrier 21, and the boss portions 23 and 25 formed on the cover 17 and the casing body 15 are supported by the differential carrier 21 via tapered roller bearings 27. The differential carrier 21 is formed with an oil reservoir. A ring gear is fixed to the differential case 5 with a bolt, and this ring gear meshes with a gear of a power transmission system. The power transmission system is connected to the transmission side, and the differential case 5 is rotationally driven by the driving force of the engine transmitted through the transmission and the power transmission system.

  The differential mechanism 7 includes a single pinion shaft 29, a pinion gear 31 supported on each pinion shaft 29, and output side gears 33 and 35. Each pinion shaft 29 engages with a through-hole 37 provided in the differential case 5 (casing body 15) and is prevented from coming off by a spring pin 39. Further, the side gears 33 and 35 mesh with the pinion gears 31 from the left and right, respectively. A spherical washer 41 is disposed between the differential case 5 and each pinion gear 31 and receives the centrifugal force of the pinion gear 31 and the meshing reaction force generated in the pinion gear 31 by meshing with the side gears 33 and 35. .

  The boss portions 43, 45 of the side gears 33, 35 are rotatably supported by support portions 47, 49 formed on the cover 17 and the casing body 15, and the boss portions 43, 45 are connected via spline-connected axles. Are connected to the left and right wheels. A thrust washer 51 is disposed between the left side gear 33 and the differential case 5 to receive the meshing reaction force of the side gear 33, and thrust washers 53, 53 are disposed between the right side gear 35 and the differential case 5. The side gear 35 receives the meshing reaction force.

  The dog clutch 9 is configured by meshing teeth 55 formed on the right side gear 35 and meshing teeth 59 formed on the clutch ring 57. Leg portions 61 are formed in the clutch ring 57 at equal intervals in the circumferential direction, and the clutch ring 57 passes through each leg portion 61 through an opening 63 formed in the casing body 15 at equal intervals in the circumferential direction. And is arranged so as to be freely movable in the axial direction. When the clutch ring 57 moves to the left as in the lower half of FIG. 1, the dog clutch 9 is engaged and the differential of the differential mechanism 7 is locked. As shown in the upper half of FIG. When moved to, the dog clutch 9 is disengaged and the differential lock is released.

  The return spring 11 is disposed between the right side gear 35 and the clutch ring 57 and urges the clutch ring 57 in the axial direction toward the engagement release side (right side) of the dog clutch 9.

  The electromagnetic actuator 1 includes an electromagnetic coil 65, a coil housing 67, a guide member 69, a plunger 71 (at least one of members constituting a magnetic path: a magnetic material having appropriate residual magnetic characteristics), a slide ring 73, , A pressure plate 75, a position switch 77, and a controller.

  The electromagnetic coil 65 is accommodated in a coil housing 67, and its lead wire is drawn out of the differential carrier 21 from the coil housing 67 via a connector, and is connected to an in-vehicle battery via a controller. The coil housing 67 is made of a magnetic material, and is fixed to the differential carrier 21 via a connecting member and is prevented from rotating. The guide member 69 is made of a nonmagnetic material (for example, stainless steel) and is welded to the inner peripheral portion of the coil housing 67. The coil housing 67 and the guide member 69 are positioned in the axial direction between the differential case 5 and the tapered roller bearing 27 by the stepped portion 79 of the boss portion 25 and the thrust washer 81.

  The plunger 71 is made of a material having an appropriate residual magnetic characteristic (for example, about S45C), and is fixed to the outer periphery of the slide ring 73. The slide ring 73 is made of a nonmagnetic material (for example, stainless steel). As will be described below, when excited by the electromagnetic coil 65, the plunger 71 has a desired residual magnetism. The plunger 71 and the slide ring 73 are disposed on the inner peripheral side of the coil housing 67 and the outer peripheral side of the guide member 69, and the inner periphery of the slide ring 73 is supported on the outer periphery of the guide member 69 so as to be axially movable. Yes. As described above, the moving direction of the plunger 71 and the slide ring 73 and the direction of the urging force of the return spring 11 are both axial directions (the same direction), and the direction of generating the moving thrust of the plunger 71 and the pressing force direction of the return spring 11 are Opposite.

  Further, the coil housing 67 is provided with a gap 83 facing the plunger 71 and a stopper portion 85 which abuts and positions when the plunger 71 moves to the left, and each contact surface 87 of the plunger 71 and the stopper portion 85, 89 is used to enhance the attractive force between the contact surfaces 87 and 89 in order to facilitate passage of the magnetic flux of the electromagnetic coil 65 and the magnetic flux due to the residual magnetism of the plunger 71 to enhance the attractive force to the plunger 71 as described below. In order to achieve this, the contact surface is processed smoothly.

  The pressure plate 75 is connected to the rotation-side clutch ring 57 by an arm portion 91 formed on the inner peripheral side, and slides in contact with the stationary-side slide ring 73. The clutch ring 57 of the dog clutch 9 urges the slide ring 73 (plunger 71) to the right via the pressure plate 75 by the urging force of the return spring 11.

  The position switch 77 has a mounting shaft 93 threaded through the differential carrier 21, and a probe 97 is formed at the tip of a position detection shaft 95 provided coaxially with the mounting shaft 93. The probe 97 is engaged with the left side surface of the pressure plate 75, and the position detection shaft 95 is urged to the right by a return spring of moderate strength provided inside. When the dog clutch 9 is engaged, the position detection shaft 95 (probe 97) of the position switch 77 moves to the left as a broken line with the movement of the pressure plate 75, and when the engagement of the dog clutch 9 is released, The return spring returns to the solid line position. Further, the position switch 77 is turned ON / OFF in accordance with the axial movement of the position detection shaft 95, and sends a signal to the controller. Based on the received ON-OFF signal, the controller determines whether or not the differential rotation of the differential device 3 (differential mechanism 7) is locked by the dog clutch 9, and the plunger 71 is differentially locked to the differential mechanism 7. Determine if it is in position.

  The coil housing 67, the gap 83, and the plunger 71 constitute a magnetic path of the electromagnetic coil 65.

The controller
(Procedure 1) A current in one direction is energized to the electromagnetic coil 65 at a predetermined current value, the plunger 71 is excited and moved to the left in the axial direction,
(Procedure 2) While stopping the energization, if necessary, a current in one direction is energized to the electromagnetic coil 65 to compensate for a decrease in residual magnetism of the plunger 71,
(Procedure 3) When a current in one direction is applied to the electromagnetic coil 65, the current supply is stopped, and a current in the opposite direction is applied to the electromagnetic coil 65 at a predetermined current value to demagnetize the plunger 71. Stop the degaussing current.

  When the electromagnetic coil 65 is not energized, the clutch ring 57, the pressure plate 75, the plunger 71, and the slide ring 73 are moved to the right by the return spring 11 as shown in FIGS. Is released, and the differential mechanism 7 is in a state where it can freely perform differential rotation.

  Next, when a current in one direction is passed through the electromagnetic coil 65 at a predetermined current value as in (Procedure 1), a magnetic flux loop 99 (FIGS. 5, 6, and 7) is generated in the magnetic path, and the magnetic force The plunger 71 is excited by this, the slide ring 73 is moved to the left together with the plunger 71, the clutch ring 57 is pressed through the pressure plate 75, the dog spring 9 is engaged while the return spring 11 is bent, and the above-mentioned Thus, the differential of the differential mechanism 7 is locked. FIG. 5 shows a state in which the plunger 71 has not yet moved to the left just after the electromagnetic coil 65 is energized in one direction. Further, when the plunger 71 moves leftward, it abuts against the stopper portion 85 of the coil housing 67 and stops and is positioned. Further, since both the guide member 69 and the slide ring 73 are made of a non-magnetic material as described above, a branch loop is generated from the magnetic flux loop 99 as shown in FIGS. In addition, magnetic loss of the electromagnetic coil 65 due to magnetic leakage is avoided.

  In addition, since the contact surfaces 87 and 89 of the plunger 71 and the stopper portion 85 are smoothly processed as described above, the magnetic flux of the electromagnetic coil 65 can easily pass therethrough, and the plunger 71 is strongly attracted by the magnetic force, and the clutch ring. A large moving operation force with respect to 57 is obtained.

  Further, as described above, the probe 97 of the position switch 77 moves to the position indicated by the broken line in FIG. 1 along with the movement of the pressure plate 75 when the dog clutch 9 is engaged, and sends a signal to the controller. Based on the signal, it is detected that the differential rotation of the differential device 3 (differential mechanism 7) is locked and that the plunger 71 is held at the differential lock position of the differential mechanism 7.

  If the differential mechanism 7 is locked in a situation where the left and right drive wheels are likely to run idle, such as when traveling on a rough road, escape of the driving force from the idle wheel is prevented, and the escape performance and running performance on rough roads are prevented. And the vehicle stacking is prevented.

  Next, when the energization of the current in one direction to the electromagnetic coil 65 is stopped as in (Procedure 2), the plunger 71 is moved to a position where the electromagnetic coil 65 is energized by residual magnetism, as shown in FIGS. And the differential lock of the differential mechanism 7 is held.

  Further, at the contact surfaces 87 and 89 of the plunger 71 and the stopper portion 85 of the coil housing 67 that are smoothly processed and the magnetic flux easily passes, the plunger 71 is strongly attracted by the residual magnetism, and the contact surface of the stopper portion 85 Since a large adsorption force acts on the plunger 71 at 89, the function of holding the differential lock state of the differential mechanism 7 by the plunger 71 is further improved.

  Further, as the time passes, the residual magnetism of the plunger 7 is attenuated, and when the plunger 71 is about to return to the right from the differential lock position of the differential mechanism 7 by the urging force of the return spring 11, the position of the plunger 71 is changed. The monitored position switch 77 detects this sign (movement) of the plunger 71 and sends a signal to the controller. The controller applies a current in one direction to the electromagnetic coil 65 to compensate for the decrease in the residual magnetism of the plunger 71. The differential lock state of the moving mechanism 7 is maintained.

  Next, when a current in one direction is applied to the electromagnetic coil 65 as in (Procedure 3), the current supply is stopped, and further, a current in the opposite direction is supplied to the electromagnetic coil 65 at a predetermined current value. A magnetic flux in a direction opposite to the magnetic flux loop 99 is generated in the magnetic path, the plunger 71 is demagnetized, and the urging force of the return spring 11 returns the clutch ring 57, the pressure plate 75, the plunger 71, and the slide ring 73 to the right, and the dog clutch 9 is released, the differential mechanism 7 becomes free to be differential, and then the demagnetizing current is stopped.

  Further, as described above, both the moving direction of the plunger 71 and the slide ring 73 and the direction of the urging force of the return spring 11 are the axial direction (the same direction), and the plunger is returned to the right by the urging force of the return spring 11. Since the plunger 71 moves smoothly with the 71 falling down and galling due to the falling down, the engagement release operation of the dog clutch 9 (differential lock release operation of the differential mechanism 7) is maintained normally.

  Even if the plunger 71 is not demagnetized, the dog clutch 9 can be disengaged by the urging force of the return spring 11. However, the demagnetization eliminates the sticking of the plunger 71. Release is performed reliably and smoothly.

  8 to 11, the relationship between the residual magnetism and thrust (thrust force) of the plunger 71 with respect to the energization current of the electromagnetic coil 65, the relationship between the residual magnetism with respect to the material of the plunger 71, and the contact surfaces 87 and 89. The relationship between the residual magnetism of the plunger 71 and the sticking force (attraction force and adsorption force) that differ for each flatness will be described.

  FIG. 8 shows the relationship between the energization current and direction of the electromagnetic coil 65 and the remanent magnetism of the plunger 71. The graph 201 shows the left side in the axial direction by energizing the electromagnetic coil 65 and exciting the plunger 71 in the above procedure 1. In this case, a residual magnetism T1 is generated in the plunger 71, and until the magnetic flux is saturated, a larger residual magnetism is generated in the plunger 71 as the energizing current value of the electromagnetic coil 65 is increased. Further, after the energization to the electromagnetic coil 65 is stopped as in the procedure 2, if a current in one direction is energized to the electromagnetic coil 65 as necessary, the residual magnetism decrease of the plunger 71 can be compensated. A graph 203 is a current in the opposite direction in which the electromagnetic coil 65 is energized in the procedure 3 to demagnetize the plunger 71, and the demagnetizing current value necessary to demagnetize the plunger 71 is A1.

  The graph 211 in FIG. 9 shows the current energized in the electromagnetic coil 65 and the moving force (thrust force: thrust force) generated in the plunger 71 at that time, and the energizing current value of the electromagnetic coil 65 remains until the magnetic flux is saturated. The larger the force, the greater the moving force is generated in the plunger 71.

  FIG. 10 shows the relationship between the magnetic material of the plunger 71 and the residual magnetism, and the graphs 221, 223, and 225 show the characteristics of the plunger 71 made of carbon steel for mechanical structure S45C, S25C, and S15C, respectively. ing. As described above, a desired remanent magnetic characteristic can be obtained by selecting the material of the plunger 71. As can be seen from this data, an extremely good characteristic of about S45C or higher can be obtained.

  FIG. 11 shows the relationship between the residual magnetism of the plunger 71 and the sticking force (attraction force and attraction force) that differ depending on the surface roughness (smoothness) of the contact surfaces 87 and 89. The graphs 231, 233, and 235 are flat surfaces, respectively. The characteristics at contact surfaces 87 and 89 of degrees 0.015 mm, 0.035 mm, and 0.1 mm are shown. Thus, desired residual magnetic characteristics can be obtained by changing the flatness of the contact surfaces 87 and 89.

  In the differential case 5, in addition to the opening 63 of the casing body 15, openings 101 and 103 are formed in the cover 17 and the casing body 15, respectively, and spiral oil grooves are formed on the inner circumferences of the boss portions 23 and 25, Radial oil grooves 105 and 107 communicating with the respective helical oil grooves are formed at the portions facing the thrust washers 53 and 55, respectively. The oil in the oil reservoir is scraped up by the rotation of the differential case 5 and the ring gear, and flows into the differential case 5 through the openings 63, 101, 103, the spiral oil groove, and the oil grooves 105, 107, and the differential. The gears 31, 35, 37 constituting the mechanism 7, the sliding parts of the casing body 15 and the clutch ring 57, the dog clutch 9 (meshing teeth 55, 59), etc. are lubricated and cooled. The lower part of the electromagnetic actuator 1 is also immersed in an oil reservoir, and a sliding part between the slide ring 73 and the guide member 69 of the plunger 71, a sliding part between the slide ring 73 and the pressure plate 75, a coil housing 67 ( The sliding portion between the guide member 69) and the stepped portion 79 and the thrust washer 81, the sliding portion between the probe 97 of the position switch 77 and the pressure plate 75, and the like are also lubricated and cooled. As a result, wear is reduced, durability is improved, and fuel consumption of the engine is improved by reducing frictional resistance at each sliding portion.

  Further, since the sliding portion between the slide ring 73 (plunger 71) and the pressure plate 75 is lubricated, torque applied to the plunger 71 and frictional resistance generated between the plunger 71 and the coil housing 67 are reduced. The operation function of the dog clutch 9 by the electromagnetic actuator 1 (the differential lock function of the differential device 3) is kept smooth and normal.

[Effect of electromagnetic actuator 1]
Since the electromagnetic actuator 1 is configured as described above, the following effects can be obtained.

  The plunger 71, which is a member constituting the magnetic path of the electromagnetic coil 65, is made of a magnetic material having an appropriate remanent magnetic characteristic, so that the plunger 71 is brought into the meshing position of the dog clutch 9 even when the energization of the electromagnetic coil 65 is stopped. Since the electric power for maintaining the state of the dog clutch 9 and the load on the battery are greatly reduced, the fuel consumption of the engine is improved, and it is necessary to use an expensive soft magnetic material for the plunger 71 with poor workability. Is gone.

  Moreover, the carbon steel for mechanical structures, which is a magnetic material having an appropriate residual magnetic property, is excellent in workability (machinability), and the processing cost can be reduced accordingly.

  Further, the appropriate residual magnetism applied to the plunger 71 is the minimum magnetic force (residual magnetism) necessary for maintaining the position. This residual magnetism gradually attenuates, and when returning the plunger 71 to the original position. Since the electromagnetic coil 65 demagnetizes the plunger 71, the amount of contamination adsorbed by the residual magnetism of the plunger 71 is substantially extremely small. Therefore, the operation of the electromagnetic actuator 1 is kept normal over a long period of time.

  In addition, since the sign that the dog clutch 9 deviates from the meshing state is detected by the position switch 77 and the plunger 71 is magnetized again to compensate for the residual magnetism, the dog clutch 9 is kept low in power consumption while keeping the power consumption of the electromagnetic coil 65 low. 9 can be held in an engaged state.

  Further, since the contact surfaces 89 and 87 between the stopper portion 85 of the coil housing 67 and the plunger 71 are processed smoothly, the magnetic resistance at the contact surfaces 89 and 87 is reduced, and the magnetic force of the electromagnetic coil 65 and the residual of the plunger 71 are reduced. In addition to strengthening the attracting force of the plunger 71 by magnetism, a large attracting force acts on the plunger 71 on the smooth contact surfaces 89 and 87, so that the engagement operation function of the dog clutch 9 by the plunger 71 and the maintaining function of the engagement state are further increased. improves.

  Further, in this configuration in which the dog clutch 9 is disengaged and released by the return spring 11 after demagnetizing the residual magnetism of the plunger 71, the return spring 11 does not need to be particularly strong, and the electromagnetic coil 65 is increased in size, power consumption, and the like. An increase in battery burden is prevented.

  Further, by making the movement direction of the plunger 71 and the direction of the urging force of the return spring 11 the same (axial direction), the plunger 71 is prevented from falling and being squeezed by the fall when the return spring 11 is pressed and moved. Since the plunger 71 moves smoothly, the operation of the electromagnetic actuator 1 is kept normal.

[Other Embodiments Included within the Scope of the Present Invention]
In the electromagnetic actuator of the present invention, the coil housing of the electromagnetic coil can be made of a magnetic material having an appropriate residual magnetic characteristic, or the plunger can be made of a magnetic material having an appropriate residual magnetic characteristic. Both coil housings may be made of a magnetic material having moderate remanent properties.

  Further, contrary to the embodiment, the operated device may be operated by the biasing member, and the operation of the operated device may be stopped by the electromagnetic actuator.

  Further, the management standard for a smooth contact surface between the stopper portion and the plunger may be surface roughness (surface accuracy) or parallelism in addition to flatness.

  The electromagnetic actuator of the present invention may be used as an actuator for operating a driving force interrupting mechanism built in a differential device, in addition to being used as an actuator for operating a differential lock mechanism of a differential device as in the embodiment.

It is sectional drawing which shows the differential apparatus 3 using the electromagnetic actuator 1 of one Embodiment. FIG. 2 is a cross-sectional view showing a state where an electromagnetic coil 65 is not energized in the electromagnetic actuator 1 of FIG. 1. In the electromagnetic actuator 1 of FIG. 1, it is sectional drawing which shows the state by which the position of the plunger 71 is hold | maintained by electricity supply of the electromagnetic coil 65 or residual magnetism. FIG. 2 is a cross-sectional view showing a state where the electromagnetic coil 65 is not energized in the electromagnetic actuator 1 of FIG. 1. In the electromagnetic actuator 1 of FIG. 1, it is sectional drawing which shows the state immediately after the energization start of the electromagnetic coil 65. FIG. In the electromagnetic actuator 1 of FIG. 1, it is sectional drawing which shows the state by which the position of the plunger 71 is hold | maintained by electricity supply of the electromagnetic coil 65. FIG. In the electromagnetic actuator 1 of FIG. 1, it is sectional drawing which shows the state by which the plunger 71 is hold | maintained by residual magnetism. 5 is a graph showing the relationship between the current and direction of an electromagnetic coil 65 and the residual magnetism of a plunger 71. 6 is a graph showing a relationship between a current value energized in an electromagnetic coil 65 and a thrust applied to a plunger 71. It is a graph which shows the relationship between the electric current value with which the electromagnetic coil 65 is supplied with electricity, and the residual magnetism of the plunger 71 for every material. It is a graph which shows the relationship between the residual magnetism of the plunger 71, and sticking force for every flatness of a contact surface. It is sectional drawing of a prior art example.

Explanation of symbols

1 Electromagnetic actuator 9 Dog clutch (operated device)
11 Return spring (biasing member)
65 Electromagnetic coil 67 Coil housing 71 Plunger (at least one of the members constituting the magnetic path: a magnetic material having appropriate residual magnetic properties)

Claims (5)

A coil housing that holds an electromagnetic coil and forms part of a magnetic path;
An electromagnetic actuator comprising a magnetic path of the electromagnetic coil together with the coil housing, and a plunger that is excited when the electromagnetic coil is energized and moves toward the operation position of the operated device,
At least one of the members constituting the magnetic path is made of a magnetic material having an appropriate remanent magnetic characteristic, and the plunger is held on the operation position side of the operated device even when energization of the electromagnetic coil is stopped. An electromagnetic actuator characterized by The invention according to claim 1,
A sensor for detecting the state of the operated device is provided,
When the sensor detects a sign that the operated device deviates from the operation state of the plunger, the electromagnetic coil is energized to compensate for a decrease in residual magnetism of the plunger and prevent the operation device from deviating from the operation state. An electromagnetic actuator characterized by that. The invention described in claim 1 or claim 2,
The coil housing is provided with a stopper portion that is positioned by abutting against the plunger moved to the operation position side of the operated device,
An electromagnetic actuator having a smooth contact surface between the stopper portion and the plunger. The invention according to any one of claims 1 to 3,
Energizing the electromagnetic coil, operating the plunger in one direction against the biasing force of the biasing member,
An electromagnetic actuator comprising: demagnetizing residual magnetism of the plunger by the electromagnetic coil, and operating the plunger in the other direction by a biasing force of the biasing member. The invention according to claim 4,
An electromagnetic actuator characterized in that the moving direction of the plunger and the direction of the urging force of the urging member are the same.

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