Solenoid type clutch device

Abstract

To suppress the leakage of magnetic flux from a solenoid device to a rotary body as much as possible.SOLUTION: A moving core comprises a moving core main body part made of a soft +magnetic material and a permanent magnet part made of a hard magnetic material. A magnetic pole direction of the permanent magnet part is matched with a magnetic pole direction of a coil during positive energization, and a stator core is non-present in a movement range of the permanent magnet part. The permanent magnet part is included in the moving core, such that the magnetic flux of the coil can be rectified by the permanent magnet part. Thus, magnetic flux to be leaked to the side of a rotary body made of the soft magnetic material can be reduced. Specifically, the magnetic pole direction of the permanent magnet part is matched with the magnetic pole direction of the coil during the positive energization, such that the rectification of magnetic flux can be performed appropriately. At the same time, since there is a non-present part of the stator core in the movement range of the permanent magnet part, loop generation of magnetic flux caused by a magnetic field of a permanent magnet is prevented and reduction of a suction force can be prevented.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present disclosure relates to a solenoid clutch device that switches between transmitting and not transmitting rotation of a rotating body by switching between energizing and de-energizing a coil, and can be used, for example, in a differential device to switch between transmitting and not transmitting rotational power between a differential case and a drive shaft. [Background technology]

[0002] In Patent Document 1, the coil, stator core, and moving core of the solenoid device are arranged coaxially with the rotor for the advantages of ease of mounting and assembly. Generally, in order to mount the solenoid device coaxially with the rotor, it is necessary to make the rotor penetrate inside the solenoid device. Also, the rotor is generally made of a soft magnetic material. Therefore, the magnetic flux generated by the excitation of the coil flows out into the rotor, which is made of a soft magnetic material, and the magnetic flux of the coil cannot be fully utilized within the solenoid device. As a result, there is a problem in that the attractive force of the clutch plate of the clutch device decreases.

[0003] In order to prevent magnetic flux from leaking to the rotor, it is possible to provide a sufficient layer of non-magnetic material between the solenoid device and the rotor, but in that case, the solenoid device would become larger, which would make it difficult to mount on a differential device or the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-240861 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, an object of the present disclosure is to minimize leakage of magnetic flux from a solenoid device to a rotating body and to suppress a decrease in the attractive force of the clutch plate of a clutch device. [Means for solving the problem]

[0006] The first aspect of the present disclosure is a solenoid clutch device including a rotor made of a soft magnetic material that rotates around an axis, a first clutch plate that rotates integrally with the rotor, a second clutch plate that is disposed opposite the first clutch plate, a coil that is fixedly disposed on the outer periphery of the rotor, a stator core made of a soft magnetic material that is fixedly disposed on the outer periphery of the rotor and forms a magnetic circuit when the coil is energized, a moving core that is disposed on the outer periphery of the rotor at the inner periphery of the coil and has a magnetic gap between it and the stator core, that forms a magnetic circuit together with the stator core when the coil is energized, and that moves in the axial direction of the rotor to narrow the magnetic gap when the coil is energized in the positive direction, a return spring that biases the stator core and the moving core in a direction that separates them from each other, and a plunger made of a nonmagnetic material that transmits the movement of the moving core in the axial direction of the rotor to either the first clutch plate or the second clutch plate. In this disclosure, positive energization of the coil refers to energization in a direction that generates a magnetic flux in the coil in a direction that narrows the magnetic gap.

[0007] In the first solenoid clutch device of the present disclosure, the moving core includes a moving core body made of a soft magnetic material and a permanent magnet part made of a hard magnetic material, and the magnetic pole direction of the permanent magnet part coincides with the magnetic pole direction when the coil is positively energized, and the stator core is not present within the moving range of the permanent magnet part.

[0008] The first solenoid clutch device of the present disclosure is provided with a permanent magnet portion in the moving core, and therefore the magnetic flux of the coil can be rectified by the permanent magnet portion. This makes it possible to reduce the magnetic flux leaking to the rotating body made of a soft magnetic material. In particular, the magnetic pole direction of the permanent magnet portion coincides with the magnetic pole direction of the coil when a positive current is applied, so that the magnetic flux can be appropriately rectified. Furthermore, since there is a non-existent portion of the stator core within the moving range of the permanent magnet portion, it is possible to prevent the generation of a magnetic flux loop due to the magnetic field of the permanent magnet, and to prevent a decrease in the attractive force.

[0009] In the second solenoid clutch device of the present disclosure, the permanent magnet portion is disposed on the side of the moving core closer to the magnetic gap. This allows the magnetic flux rectification effect of the permanent magnet portion to be more appropriate, and reduces leakage of magnetic flux to the rotating body. In addition, a portion of the moving core body on the magnetic gap side is interposed between the permanent magnet portion and the magnetic gap in the moving core. The thickness of this portion on the magnetic gap side is a predetermined thickness determined according to the size of the magnetic gap (stroke of the moving core). For example, it is equal to or greater than the thickness of the permanent magnet portion. This makes it possible to prevent the moving core from being attracted to the stator core by magnetic force when the coil is not energized.

[0010] In the third solenoid clutch device of the present disclosure, even if the coil is de-energized while the magnetic gap is narrowed by energizing the coil in a forward direction, the position of the moving core and the stator core is maintained by the magnetic force of the permanent magnet. On the other hand, when the coil is reversely energized, the moving core moves in the axial direction of the rotor so as to widen the magnetic gap due to the repulsive force between the coil and the permanent magnet and the biasing force of the return spring, and even if the coil is de-energized while the magnetic gap is widened by energizing the coil in a reverse direction, the position of the moving core and the stator core is maintained by the biasing force of the return spring. In the third solenoid clutch device of the present disclosure, even if the coil is de-energized, the magnetic gap can be maintained in both a narrowed state and a widened state.

[0011] In the fourth solenoid clutch device of the present disclosure, a bearing member made of a non-magnetic material is interposed between the inner circumference of the moving core and the outer circumference of the rotating body. The bearing member not only supports the rotation of the rotating body, but also holds the moving core.

[0012] In the fifth solenoid clutch device of the present disclosure, the rotor includes a cylindrical outer rotor and a cylindrical shaft disposed on the inner circumference of the outer rotor. The solenoid clutch device of the present disclosure can be used for a variety of purposes, but the fifth solenoid clutch device can also be used when the rotor has a double structure.

[0013] In the sixth solenoid clutch device of the present disclosure, the outer circumferential rotor corresponds to a differential case of a differential device, the shaft corresponds to a drive shaft of the differential device, the first clutch plate corresponds to a first dog clutch of the differential device, and the second clutch plate corresponds to a second dog clutch of the differential device. Rotation of the differential case is transmitted to the drive shaft via a ring gear, a first dog clutch, a second dog clutch, a pinion gear, and a side gear of the differential device. The fourth solenoid clutch device of the present disclosure is suitable for use in the dog clutch of the differential device.

[0014] In a seventh solenoid clutch device of the present disclosure, the differential gear is disposed in the powertrain unit, and the differential case is rotationally supported by the powertrain unit through a differential case bearing. Because the differential case, which corresponds to the rotating body, is rotationally supported by the powertrain unit through the differential case bearing, the solenoid clutch device is not subjected to an excessive rotational load of the rotating body. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram showing the configuration of a differential device in which a solenoid clutch device is used. [Diagram 2] FIG. 2 is an exploded perspective view showing the configuration of a differential device. [Diagram 3] 1 is a cross-sectional view showing a differential gear in which a solenoid clutch device is used. [Figure 4] FIG. 4 is a perspective view showing a ring gear and a first dog clutch of the differential device. [Diagram 5] 4 is a perspective view showing a disengaged state of a first dog clutch and a second dog clutch. FIG. [Figure 6] FIG. 4 is a perspective view showing an engaged state of a first dog clutch and a second dog clutch. [Figure 7] FIG. 4 is a perspective view showing an engaged state between a second dog clutch and a pinion gear. [Figure 8] FIG. 4 is a perspective view showing an engagement state between a pinion gear and a side gear. [Figure 9]5A and 5B are diagrams illustrating rotation transmission in an engaged state of the solenoid clutch device. [Figure 10] 5A and 5B are diagrams illustrating rotation transmission in a disengaged state of the solenoid clutch device. [Figure 11] FIG. 4 is a cross-sectional view showing a solenoid clutch device in a disengaged state. [Figure 12] FIG. 4 is a cross-sectional view showing an engaged state of the solenoid clutch device. [Figure 13] 4A and 4B are diagrams illustrating magnetic fluxes in a solenoid clutch device according to the present disclosure and a solenoid clutch device according to a comparative example. [Figure 14] 5A and 5B are diagrams illustrating the relationship between stroke and attractive force in a solenoid clutch device of the present disclosure and a solenoid clutch device of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An example in which the solenoid clutch device 100 of the present disclosure is used in a differential device 200 will be described below. An outline of the configuration is shown in Fig. 1. The differential device 200 is used in a four-wheeled vehicle, and transmits the driving force of a motor 300 to left and right tires (not shown) while allowing the left and right tires to rotate at different speeds. The motor 300 and the differential device 200 are arranged in a powertrain unit 400 together with the solenoid clutch device 100.

[0017] The motor 300 is fixed to the powertrain unit 400, and the motor shaft 301 is rotatably supported by the powertrain unit 400 via a motor shaft bearing 401. The rotation of the motor shaft 301 is transmitted to the intermediate shaft 304 by meshing between a motor gear 302 and a first reduction gear 303. The intermediate shaft 304 is also rotatably supported by the powertrain unit 400 via an intermediate shaft bearing 402. Note that although the motor shaft bearing 401, the intermediate shaft bearing 402, etc. are simply illustrated using symbols, various types of bearings such as ball bearings and roller bearings can be used.

[0018] The rotation of the intermediate shaft 304 is transmitted from the second reduction gear 305 to the ring gear 201 of the differential gear 200. The number of teeth of the first reduction gear 303 is set to be greater than the number of teeth of the motor gear 302, and the number of teeth of the ring gear 201 is set to be greater than the number of teeth of the second reduction gear 305. Therefore, the rotation of the motor 300 is reduced in speed before being transmitted to the differential gear 200. As a result, the rotational torque transmitted to the differential gear 200 becomes large. Note that the ring gear 201, the second reduction gear 305, the first reduction gear 303, and the motor gear 302 are all helical gears, and have a high meshing ratio.

[0019] Next, the configuration of the differential gear 200 will be described with reference to Figs. 2 to 8. Fig. 2 is an exploded perspective view showing the main components of the differential gear 200. As described above, the ring gear 201 rotates by receiving the rotation of the motor 300. A pair of differential cases (one side differential case 210 and the other side differential case 211) are fixedly disposed on both sides of the ring gear 201 by welding or the like. Therefore, the one side differential case 210 and the other side differential case 211 rotate together with the ring gear 201. The pair of differential cases (one side differential case 210 and the other side differential case 211) are rotationally supported by the power train unit 400 by differential case bearings 403. In the present disclosure, as shown in Fig. 3, the solenoid clutch device 100 is disposed on the outer periphery of the one side differential case 210, so that the one side differential case 210 becomes a rotating body.

[0020] As shown in FIG. 4, the ring gear 201 is formed with four engagement recesses 202 spaced apart in the circumferential direction. The engagement protrusions 221 of the first dog clutch 220 are fitted into the engagement recesses 202. Therefore, the first dog clutch 220 rotates integrally with the ring gear 201. As shown in FIG. 5, the first dog clutch 220 is ring-shaped. A large number of first dog teeth 222 are formed on the surface of the first dog clutch 220 opposite to the engagement protrusions 221. The second dog clutch 230 is disposed opposite to the first dog clutch 220, and the second dog clutch 230 is also ring-shaped. The second dog clutch 230 is also formed with second dog teeth 231 with which the first dog teeth 222 of the first dog clutch 220 mesh. FIG. 6 shows a state in which the first dog teeth 222 of the first dog clutch 220 and the second dog teeth 231 of the second dog clutch 230 are engaged with each other.

[0021] 7, a pair of pinion gears (one side pinion gear 240 and the other side pinion gear 241) are arranged on the inner circumference of the ring-shaped second dog clutch 230. The one side pinion gear 240 and the other side pinion gear 241 rotate together with the second dog clutch 230 via a one side pin 242 and an other side pin 243. In other words, the second dog clutch 230 rotates together with the pair of pinion gears arranged on the inner circumference.

[0022] The pair of pinion gears (one side pinion gear 240 and the other side pinion gear 241) can rotate around the one side pin 242 and the other side pin 243, respectively. Therefore, the pair of pinion gears can rotate around the one side pin 242 and the other side pin 243 while revolving together with the second dog clutch 230.

[0023] As shown in Fig. 8, a pair of pinion gears (one side pinion gear 240 and the other side pinion gear 241) mesh with a pair of side gears (one side side gear 250 and the other side side gear 251). Although omitted in Figs. 2, 7, and 8, gear teeth are formed on the conical surfaces of the pair of pinion gears (one side pinion gear 240 and the other side pinion gear 241). In addition, gear teeth are also formed on the conical surfaces of the pair of side gears (one side side gear 250 and the other side side gear 251) facing the pair of pinion gears, and the two transmit rotational force by meshing of the gear teeth.

[0024] Returning to FIG. 1, the pair of side gears (one side gear 250 and the other side gear 251) are respectively connected to a pair of drive shafts (one side drive shaft 260 and the other side drive shaft 261). Therefore, the rotational force of the motor 300 received via the ring gear 201 is transmitted to the one side drive shaft 260 and the other side drive shaft 261 via the differential device 200. The one side drive shaft 260 is disposed on the inner circumference of the cylindrical one side differential case 210. Therefore, for the solenoid clutch device 100, the one side differential case 210 is the outer circumferential rotating body, and the one side drive shaft 260 is a cylindrical shaft disposed on the inner circumference thereof.

[0025] As shown in FIG. 1, a sensor disk 270 is fixed to the one side differential case 210. Therefore, the sensor disk 270 rotates together with the ring gear 201 and the one side differential case 210. A position sensor 271 is arranged corresponding to this sensor disk 270. In a typical example, the position sensor 271 is a Hall sensor that detects a change in magnetic flux of a magnet arranged on the sensor disk 270. In this way, the rotation direction and rotation speed of the ring gear 201 are detected. Of course, it is possible to use another position sensor 271 such as a resolver. Note that a return spring 107 that biases the first dog clutch 220 in a direction that separates it from the second dog clutch 230 is arranged on the sensor disk 270, but the return spring 107 will be described later in the solenoid clutch device 100.

[0026] Next, the rotation transmission of the motor 300 will be described with reference to FIG. 9. The motor 300 can be switched between forward and reverse rotation by a control device (not shown). The forward direction of the vehicle is the forward rotation, and the backward direction is the reverse rotation. The rotation speed of the motor 300 can also be controlled by a control device (not shown). Suppose that the rotation direction R1 of the motor shaft 301 in FIG. 9 is forward rotation. In that case, the rotation direction R2 of the intermediate shaft 304 is reversed, and the rotation direction R3 of the ring gear 201 is forward rotation. As described above, the rotation force of the motor 300 is reduced by the reduction ratio between the motor gear 302 and the first reduction gear 303 and the reduction ratio between the second reduction gear and the ring gear 201, and the drive torque is increased to transmit the rotation force of the motor 300 to the ring gear 201.

[0027] When the solenoid clutch device 100 is in an ON state, the first dog teeth 222 and the second dog teeth 231 of the first dog clutch 220 and the second dog clutch 230 are engaged with each other. Therefore, the forward rotation of the ring gear 201 is transmitted to the second dog clutch 230 via the first dog clutch 220, and the second dog clutch 230 also rotates forward. The revolution direction R4 of the one-side pinion gear 240 and the other-side pinion gear 241 that revolve together with the second dog clutch 230 also rotates forward. The revolution of the one-side pinion gear 240 and the other-side pinion gear 241 is transmitted to the one-side drive shaft 260 and the other-side drive shaft 261 via the one-side side gear 250 and the other-side side gear 251. Therefore, the rotation direction R5 of the one-side drive shaft 260 and the other-side drive shaft 261 also rotates forward.

[0028] When the car is traveling straight, the pair of pinion gears revolve without rotating, and the rotation speed of one side drive shaft 260 and the other side drive shaft 261 is equal. When the car is turning, one side pinion gear 240 and the other side pinion gear 241 rotate while revolving, so that the rotation speed of the drive shaft located on the outside of the curve can be made higher than the rotation speed of the drive shaft located on the inside of the curve.

[0029] Next, the configuration of the solenoid clutch device 100 will be described with reference to Figures 11 and 12. In this example, the solenoid clutch device 100 switches between engagement and disengagement of a first dog clutch 220 and a second dog clutch 230. Therefore, in this example, the first dog clutch 220 corresponds to a first clutch plate, and the second dog clutch 230 corresponds to a second clutch plate. 101 is a coil made of copper wire insulated with an enamel coating wound many times. This coil 101 is wound around a cylindrical bobbin 102 made of a resin material. The bobbin is made of, for example, polybutylene terephthalate (PBT) or the like.

[0030] When a current is applied to the coil 101, the coil 101 is excited. To form a magnetic circuit at that time, a stator core 103 is arranged on both sides and the outer circumference of the coil 101. The stator core 103 is made of a soft magnetic material that has a small magnetic force retention and a large magnetic permeability. For example, ferritic stainless steel, permalloy, electromagnetic steel sheet, etc. Therefore, when the coil 101 is energized, a magnetic circuit is formed, but when the coil 101 is not energized, the stator core 103 is not magnetized by the coil 101. However, even when the coil is not energized, the stator core 103 is magnetized by the magnetic force of the permanent magnet portion 112. The position of the moving core 110 can be maintained depending on the degree of this magnetization. The position of the moving core 110 will be described later.

[0031] The stator core 103 has a cylindrical shape with an outer diameter of about 100 mm. A moving core 110 is disposed opposite the stator core 103 with a magnetic gap 104 interposed therebetween. In this disclosure, the moving core 110 is composed of a moving core main body 111 made of a soft magnetic material and a permanent magnet part 112 made of a hard magnetic material. The hard magnetic material has a large residual magnetic flux density and functions as a permanent magnet.

[0032] A moving core tip portion 111A made of a soft magnetic material is disposed on the surface of moving core 110 (moving core main body portion 111) facing magnetic gap 104 with stator core 103. Moving core 110 is disposed on the inner circumference of ring-shaped stator core 103. It is also disposed on the outer circumference of one side differential case 210 corresponding to the rotor (particularly the outer circumferential rotor). Moving core 110 is disposed so as to be movable in the axial direction of the rotor (one side differential case 210).

[0033] The stator core 103 and the coil 101 are fixedly disposed in the power train unit 400. In this example, a bearing member 105 is disposed between the stator core 103 and the rotor (one side differential case 210). The bearing member 105 is made of a non-magnetic material that is not magnetized and is therefore not affected by magnetic fields. Stainless steel, for example, is used as the non-magnetic material of the bearing member 105. Therefore, the bearing member 105 and the moving core 110 are rotationally supported by the one side differential case 210. The bearing load of the one side differential case 210 is borne by the differential case bearing 403, and in this state, the bearing member 105 slidably supports the moving core 110. The inner diameter of the bearing member 105 is formed to be slightly larger than the outer diameter of the one side differential case 210. The outer diameter of the one side differential case 210 is, for example, about 55 millimeters.

[0034] The moving core 110 is connected to a first dog clutch 220, which corresponds to the first clutch plate, by a plunger 106 made of a non-magnetic material. The plunger 106 is also made of stainless steel and has a cylindrical shape that covers one side differential case 210, which is a rotating body. One end face of the cylindrical plunger 106 is fixed to the first dog clutch 220, and the moving core 110 is fixed to the outer circumferential surface. However, the plunger 106 does not necessarily have to be fixed as long as it abuts against the first dog clutch 220.

[0035] FIG. 11 shows the state when the coil 101 is not energized. The first dog clutch 220 is separated from the second dog clutch 230 by the biasing force of the return spring 107. FIG. 12 shows the state when the coil 101 is energized in the positive direction from the state shown in FIG. 11, and a magnetic circuit is formed around the coil 101 by the stator core 103 and the moving core 110. When the coil 101 is energized in the positive direction, a magnetic force acts to reduce the magnetic gap 104 present in the magnetic circuit. The magnetic force at that time is set to be larger than the biasing force of the return spring 107. Therefore, the moving core 110 moves the first dog clutch 220 via the plunger 106, and brings it into mesh with the second dog clutch 230.

[0036] 11 and 12, a portion of stator core 103 that is within the range of movement of permanent magnet portion 112 is cut out to form non-existent portion 108 of stator core 103. This is to prevent the occurrence of a magnetic flux loop due to the magnetic field of permanent magnet portion 112 by configuring a magnetic circuit in such a way that no magnetic material is present on the surface facing permanent magnet portion 112. If a magnetic flux loop occurs, the attractive force in magnetic gap 104 will decrease, so by providing non-existent portion 108, it is possible to prevent the attractive force from decreasing.

[0037] Fig. 13 compares an example in which a permanent magnet portion 112 is arranged on moving core 110 with an example in which a permanent magnet portion 112 is not provided. The upper side is an example in which a permanent magnet portion 112 is not provided. The closer to black the color, the stronger the magnetic flux. It can be seen that a magnetic circuit is formed in stator core 103 and moving core 110 when coil 101 is positively energized. It can also be seen that magnetic flux passes through magnetic gap 104, and moving core 110 is attracted to stator core 103 by magnetic gap 104.

[0038] However, as shown in the upper part of FIG. 13, a part of the magnetic flux flows to the one side differential case 210 side, which is the rotating body. This is because the one side differential case 210 and the moving core 110 are made of the same soft magnetic material. The magnetic flux that flows to the one side differential case 210 side does not contribute at all to the attraction of the moving core 110. The exciting force of the coil 101 is wasted. In the example of FIG. 13, only the one side differential case 210 is arranged as the inner and outer circumferential rotating body of the rotating body, but in reality, the one side drive shaft 260 is arranged on the inner circumferential side of the one side differential case 210. Since the one side drive shaft 260 is also made of a soft magnetic material, the leakage of magnetic flux to the rotating body side becomes larger.

[0039] In contrast, as shown in the lower part of Fig. 13, when permanent magnet portion 112 is provided, the magnetic flux of coil 101 is rectified by permanent magnet portion 112. This is because the magnetic pole direction of permanent magnet portion 112 matches the magnetic pole direction of coil 101 when positive current is applied. Although the magnetic flux leaking to one side differential case 210 is not zero, it is significantly reduced compared to the upper side. Also, as described above, the portion facing permanent magnet portion 112 is non-existence portion 108 of stator core 103, so no magnetic flux loop is generated by permanent magnet portion 112 in non-existence portion 108.

[0040] 13, in order to reduce the magnetic flux leaking to the one-side differential case 210 side, which is the rotating body, it is desirable to bring the permanent magnet section 112 closer to the magnetic gap 104 side. In other words, the thickness of the moving core tip section 111A of the moving core 110 (moving core main body section 111) is determined by how to utilize the magnetic force of the permanent magnet section 112. In this embodiment, the permanent magnet section 112 is also used to hold the position of the moving core 110.

[0041] As described above, when the coil 101 shown in FIG. 11 is not energized, the first dog clutch 220 is separated from the second dog clutch 230 by the biasing force of the return spring 107. On the other hand, when the coil 101 is energized in the forward direction from the state shown in FIG. 11, the magnetic gap 104 narrows as shown in FIG. 12, and the first dog clutch 220 meshes with the second dog clutch 230. Even if the coil 101 is not energized in this state, the state shown in FIG. 12 can be maintained by the magnetic force of the permanent magnet portion 112. That is, in this embodiment, both the disengaged state between the first dog clutch 220 and the second dog clutch 230 shown in FIG. 11 and the engaged state between the first dog clutch 220 and the second dog clutch 230 shown in FIG. 12 can be maintained without energizing the coil 101.

[0042] In this embodiment, to switch from the engaged state shown in Fig. 12 to the disengaged state shown in Fig. 11, reverse current is passed through coil 101. Reverse current is passed through coil 101 with the positive and negative poles reversed from those of forward current. When reverse current is passed, the excitation force generated in coil 101 repels the magnetic force of permanent magnet portion 112, widening magnetic gap 104. Once magnetic gap 104 has widened, that state is maintained by the biasing force of return spring 107.

[0043] Therefore, the relationship between the biasing force of the return spring 107 and the magnetic force of the permanent magnet portion 112 is as follows. When the magnetic gap 104 narrows and the first dog clutch 220 and the second dog clutch 230 are in an engaged state, the magnetic force of the permanent magnet portion 112 is greater than the biasing force of the return spring 107. Conversely, when the magnetic gap 104 widens and the first dog clutch 220 and the second dog clutch 230 are in a disengaged state, the biasing force of the return spring 107 becomes greater than the magnetic force of the permanent magnet portion 112. The thickness of the moving core tip portion 111A described above is determined so as to set the magnetic force of the permanent magnet portion 112 in this manner. In this embodiment, the thickness of the moving core tip portion 111A is set to be equal to or greater than the thickness of the permanent magnet portion 112. That is, the magnetic force of the permanent magnet portion 112 is adjusted by interposing the moving core tip portion 111A having a predetermined thickness on the magnetic gap 104 side of the permanent magnet portion 112.

[0044] In this manner, in the present disclosure, by arranging the permanent magnet portion 112 in an appropriate position on the moving core 110, it is possible to most efficiently utilize the exciting force when the coil 101 is positively energized. Figure 14 shows the upper and lower examples of Figure 13 in terms of the relationship between stroke and attractive force. Note that the attractive force in Figure 14 is the attractive force generated in the magnetic gap 104 when the coil 101 is positively energized. The upper example is indicated by A, and the lower example is indicated by B. The behavior of the solenoid clutch device 100 is the same, but the lower example B has a higher attractive force over the entire stroke.

[0045] In this example, since the permanent magnet portion 112 is used, the first dog clutch 220 and the second dog clutch 230 can be engaged with a high attractive force, and the engagement can be maintained. In other words, in this example, the coil 101 required to exert a sufficient attractive force for engagement can be made smaller.

[0046] As shown in Fig. 9, during engagement, the rotation of the motor 300 is transmitted to the one-side drive shaft 260 and the other-side drive shaft 261 via the differential gear 200. On the other hand, during disengagement, as shown in Fig. 10, the transmission of rotation R5 of the one-side drive shaft 260 and the other-side drive shaft 261 ends at the second dog clutch 230, and the rotation is not transmitted to the motor 300. Since a counter electromotive force is generated when the motor 300 is rotated, when the automobile is allowed to run by inertia, the first dog clutch 220 and the second dog clutch 230 are disengaged. When the motor 300 is used for regenerative braking or power generation, the first dog clutch 220 and the second dog clutch 230 are engaged.

[0047] The above is a preferred example of the present disclosure, but the present disclosure can be modified in various ways. For example, the bearing member 105 is preferred for supporting the moving core 110, but it can be eliminated. Eliminating the bearing member 105 allows the solenoid clutch device 100 to be made smaller.

[0048] In the above example, the first dog clutch 220 and the second dog clutch 230 are engaged when the coil 101 is positively energized, and then, even when the coil 101 is de-energized, the engaged state is maintained by the magnetic force of the permanent magnet portion 112. This is a desirable example because the engaged state and the disengaged state can be maintained without energizing the coil 101. However, it is possible to maintain the engaged state by the excitation force of the coil 101 by reducing the magnetic force of the permanent magnet portion 112 or increasing the thickness of the moving core tip portion 111A.

[0049] In the solenoid clutch device 100 of the present disclosure, the movement of the moving core 110 can be transmitted to either the first clutch plate or the second clutch plate. The movement of the moving core 110 can be used to engage the first clutch plate and the second clutch plate, or to disengage them.

[0050] In the above example, the solenoid clutch device 100 is used to engage the first dog clutch 220 and the second dog clutch 230, but the differential device 200 can also be used for other purposes. For example, it can be used as a limited slip differential device that is used in a situation where one of the drive shafts cannot rotate due to tire slip.

[0051] Furthermore, the solenoid clutch device 100 of the present disclosure is not limited in use to the differential device 200. As long as the solenoid clutch device 100 is disposed on the outer periphery of a rotor made of a soft magnetic material, it can be used in a wide range of applications, not limited to the differential device 200.

[0052] The above-mentioned materials and sizes are merely examples and can be appropriately selected according to the required performance. The disclosure in this specification and drawings is not limited to the exemplified embodiments. The disclosure includes the exemplified embodiments and modifications thereto by those skilled in the art.

[0053] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple dependent claims. Some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. Furthermore, some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. The claims described in these multiple dependent forms define multiple technical ideas.

[0054] (Technical thought 1) A rotor made of a soft magnetic material that rotates around an axis; a first clutch plate that rotates integrally with the rotor; a second clutch plate disposed opposite the first clutch plate; A coil fixedly disposed on an outer periphery of the rotor; a stator core made of a soft magnetic material, the stator core being fixed to an outer periphery of the rotor and constituting a magnetic circuit when the coil is energized; a moving core disposed on the inner circumference of the coil and on the outer circumference of the rotor with a magnetic gap between the moving core and the stator core, forming a magnetic circuit together with the stator core when the coil is energized, and moving in the axial direction of the rotor so as to narrow the magnetic gap when the coil is energized in the positive direction; a return spring that biases the stator core and the moving core in a direction to separate them from each other; a plunger made of a non-magnetic material that transmits the axial movement of the rotating body of the moving core to either the first clutch plate or the second clutch plate, The moving core includes a moving core body portion made of a soft magnetic material and a permanent magnet portion made of a hard magnetic material, The magnetic pole direction of the permanent magnet portion coincides with the magnetic pole direction of the coil when a positive current is applied, The stator core is not present within the moving range of the permanent magnet portion. A solenoid clutch device.

[0055] (Technical thought 2) The permanent magnet portion is disposed on the side of the moving core that is closer to the magnetic gap, and the moving core tip portion of the moving core body is interposed between the permanent magnet portion of the moving core and the magnetic gap, and the thickness of the moving core tip portion is a predetermined thickness determined according to the size of the magnetic gap. A solenoid clutch device according to Technical Idea 1.

[0056] (Technical Thought 3) When the coil is energized to narrow the magnetic gap, the positions of the moving core and the stator core are maintained by the magnetic force of the permanent magnet portion even if the coil is de-energized. When reverse current is applied to the coil, the moving core moves in the axial direction of the rotor to widen the magnetic gap due to the repulsive force between the coil and the permanent magnet portion and the biasing force of the return spring. When the coil is reversely energized to widen the magnetic gap, the positions of the moving core and the stator core are maintained by the biasing force of the return spring even when the coil is de-energized. A solenoid clutch device according to Technical Idea 1 or Technical Idea 2.

[0057] (Technical Thought 4) A bearing member made of a non-magnetic material is interposed between the inner periphery of the moving core and the outer periphery of the rotating body. A solenoid clutch device according to any one of Technical Ideas 1 to 3.

[0058] (Technical Thought 5) The rotor includes a cylindrical outer rotor and a cylindrical shaft disposed on the inner periphery of the outer rotor. A solenoid clutch device according to any one of Technical Ideas 1 to 4.

[0059] (Technical Thought 6) The outer peripheral rotor corresponds to a differential case of a differential gear, the shaft corresponds to a drive shaft of the differential gear, the first clutch plate corresponds to a first dog clutch of the differential gear, and the second clutch plate corresponds to a second dog clutch of the differential gear, and rotation of the differential case is transmitted to the drive shaft via a ring gear, the first dog clutch, the second dog clutch, a pinion gear, and a side gear of the differential gear. A solenoid clutch device according to Technical Idea 5.

[0060] (Technical Thought 7) The differential gear is disposed in a power train unit, and the differential case is rotationally supported by the power train unit through a differential case bearing. A solenoid clutch device according to Technical Idea 6. [Explanation of symbols]

[0061] 100 Differential 101 Coil 103 Stator core 104 Magnetic Gap 105 Bearing materials 106 Plunger 107 Return spring 108 Non-existence part 110 Moving Core 111 Moving core body 112 Permanent magnet section 210 Rotating first differential case 220 First dog clutch which becomes the first clutch plate 230 Second dog clutch which becomes the second clutch plate

Claims

1. A rotating body made of a soft magnetic material that rotates around an axis, A first clutch plate that rotates integrally with the rotating body, A second clutch plate disposed opposite to the first clutch plate, A coil fixedly disposed on the outer periphery of the rotating body, A stator core made of a soft magnetic material that is fixedly disposed on the outer periphery of the rotating body and forms a magnetic circuit when the coil is energized, A moving core that is disposed on the outer periphery of the rotating body inside the coil, with a magnetic gap interposed between it and the stator core, forms a magnetic circuit together with the stator core when the coil is energized, and moves in the axial direction of the rotating body to narrow the magnetic gap when the coil is energized in the forward direction, A return spring that biases the stator core and the moving core in a direction to separate them from each other, And a plunger made of a non-magnetic material that transmits the axial movement of the moving core of the rotating body to either the first clutch plate or the second clutch plate. The moving core includes a moving core main body portion made of a soft magnetic material and a permanent magnet portion made of a hard magnetic material. The magnetic pole direction of the permanent magnet portion coincides with the magnetic pole direction when the coil is energized in the forward direction, rectifying the magnetic flux when the coil is energized in the forward direction by the permanent magnet portion. In the moving range of the permanent magnet portion, as a magnetic circuit configuration where the stator core is non-existent and no magnetic material exists on the opposing surface of the permanent magnet portion, the reduction in the attractive force at the magnetic gap during the forward energization of the coil due to the generation of a magnetic flux loop by the magnetic field of the permanent magnet portion is suppressed. A solenoid type clutch device characterized by the above.

2. The permanent magnet portion is disposed inside the moving core, closer to the magnetic gap side, and between the inner permanent magnet portion of the moving core and the magnetic gap, the tip portion of the moving core main body of the moving core is interposed, and the thickness of this tip portion of the moving core is a predetermined thickness determined according to the size of the magnetic gap. The solenoid clutch device according to claim 1, characterized in that...

3. With the coil energized in the normal direction to narrow the magnetic gap, even when the coil is de-energized, the positions of the moving core and the stator core are held by the magnetic force of the permanent magnet portion. When the coil is energized in the reverse direction, the moving core moves in the axial direction of the rotating body to widen the magnetic gap due to the repulsive force between the coil and the permanent magnet portion and the biasing force of the return spring. With the coil energized in the reverse direction to widen the magnetic gap, even when the coil is de-energized, the positions of the moving core and the stator core are held by the biasing force of the return spring. The solenoid clutch device according to claim 2, characterized in that...

4. A bearing member made of a non-magnetic material is interposed between the inner circumference of the moving core and the outer circumference of the rotating body. The solenoid clutch device according to claim 1 or claim 2, characterized in that...

5. The rotating body includes a circular tubular outer peripheral rotating body and a cylindrical shaft disposed on the inner circumference of the outer peripheral rotating body. The solenoid clutch device according to claim 1 or claim 2, characterized in that...

6. The outer peripheral rotating body corresponds to the differential case of the differential device, the shaft corresponds to the drive shaft of the differential device, the first clutch plate corresponds to the first dog clutch of the differential device, the second clutch plate corresponds to the second dog clutch of the differential device, and the rotation of the differential case is transmitted to the drive shaft through the ring gear, the first dog clutch, the second dog clutch, the pinion gear, and the side gear of the differential device. The solenoid clutch device according to claim 5, characterized in that...

7. The differential device is arranged in the power train unit, and the differential case is rotatably supported in the power train unit by a differential case bearing. The solenoid clutch device according to claim 6, characterized in that.

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