JP6557115B2 - Electric clutch - Google Patents

Description

  The present invention relates to an electric clutch (hereinafter also simply referred to as “clutch”) that transmits torque by frictionally engaging a friction plate and a mating plate using electromagnetic force generated by a coil.

  An electric clutch basically includes an armature that provides a pressing force for frictionally engaging a friction plate and a mating plate, and a yoke including a coil is disposed with respect to the armature via a gap. Yes. When the coil is energized, a magnetic field is generated in the yoke, and the armature is attracted to the yoke, whereby the friction plate and the mating plate are frictionally engaged.

  However, in the configuration in which the realization and maintenance of the frictional engagement state depends only on the electromagnetic force of the coil, the armature is attracted and the response when the friction plate and the mating plate are frictionally engaged is improved or sufficient load is applied. In order to do this, it is necessary to increase the size of the coil. In this case, there is a problem that the entire clutch is also increased in size. Then, there exist the following as an electric clutch developed in order to eliminate the above problems.

JP 2005-48788 A JP 2006-342937 A

  In Patent Document 1, a rotor (yoke) and an armature including a coil, a friction plate and a mating plate are arranged in parallel in the axial direction, and a ball is sandwiched between the armature and the mating plate on the coil side. An electric clutch having a booster mechanism is disclosed. The friction plate is spline-fitted to the inner peripheral side of the housing, which is the input shaft. On the other hand, the mating plate is spline-fitted on the output shaft. Torque is transmitted from the shaft to the output shaft. The rotor is screwed to the inner peripheral side of the housing.

  Here, when the coil is energized, the armature is attracted to the rotor, the distance between the armature and the mating plate on the coil side increases, and the armature rotates at the same time, so the ball rides on the armature and the mating plate on the coil side Push toward the friction plate. As a result, since the mating plate and the friction plate are in strong contact with each other, a large torque can be transmitted even if the current flowing through the coil is small.

  In Patent Document 2, in an electric clutch having the same configuration as the conventional one, an electric coil provided with a main coil in which a small number of thick copper wires are wound and an auxiliary coil in which a large number of thin copper wires are wound as coils provided in a yoke. A clutch is disclosed. According to this, when starting the frictional engagement between the friction plate and the mating plate, it is possible to generate a large electromagnetic attraction force by energizing the main coil, and after the frictional engagement, switching to energization of the auxiliary coil. Thus, the friction engagement state can be maintained.

  In the case of the electric clutch of the cited document 1, it is easy to ensure the fastening load between the friction plate and the mating plate by the booster mechanism. However, in such a configuration, when the friction material affixed to the friction plate is worn, the mating plate cannot be sufficiently pressed against the friction plate, and a sufficient fastening load cannot be secured. In addition, it is difficult to cope with so-called slip control in which the load applied to the mating plate is precisely controlled so that the friction plate and the mating plate slip to each other to prevent the occurrence of vibration.

  On the other hand, in the case of the electric clutch of the cited document 2, it is necessary to set a large gap when the coil is energized between the yoke and the armature at the time of assembly in consideration of wear of the friction material stuck to the friction plate. In order to prevent a load drop, it is necessary to enlarge the main coil. Therefore, the electric clutch as a whole is increased in size. Further, when the friction material is worn, the gap when the coil is energized between the yoke and the armature becomes small, so that a large main coil has an excessive fastening load, and power is wasted correspondingly. In addition, because the main coil is energized and the friction plate and the mating plate are frictionally engaged, an impact load is applied during fastening, and the friction force between the mating plate and the friction plate changes abruptly when released. At that time, a shock is likely to occur, and it is difficult to cope with slip control.

  SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, the present invention has an object to provide a compact electric clutch that realizes a good fastening load throughout the life of a product and is easily compatible with slip control. To do.

The present invention includes a non-rotatable housing;
A plurality of mating plates that are spline-fitted on the first rotating shaft;
A friction plate that is spline-fitted onto the second rotating shaft and disposed between the mating plates;
A linear motion conversion mechanism attached to the housing for converting torque into linear motion;
Drive means for transmitting torque to the linear motion conversion mechanism;
A yoke that is provided so as to be able to move forward and backward with respect to the housing in conjunction with the linear motion conversion mechanism;
An armature provided so as to be rotatable relative to the housing via a gap with respect to the yoke, and capable of moving forward and backward relative to the housing in conjunction with the linear motion conversion mechanism;
The armature is provided so as to face the mating plate and face the armature in the yoke direction, and has a pressing surface that approaches or separates from the mating plate in conjunction with the forward and backward movement of the armature. The said subject was solved by the electric clutch characterized by the above-mentioned.

  According to the present invention, the torque is transmitted to the linear motion conversion mechanism by the driving means, and the torque is converted into the linear motion by the linear motion conversion mechanism. As a result, the pressing surface is moved closer to or away from the counterpart plate. be able to. That is, by controlling the driving means, the armature pressing surface can be brought into contact with the mating plate and the mating plate and the friction plate can be brought into close contact with each other without depending on the energization of the coil. It is easy to relax and it is easy to cope with slip control. Also, by controlling the driving means from the contact state between the pressing surface and the mating plate and keeping the pressing surface a predetermined distance away from the mating plate, the optimum clutch clearance (the pressing surface and It is possible to set a gap between the counter plate).

  In addition, as described above, the contact between the pressing surface and the mating plate and the close contact between the mating plate and the friction plate can be realized by the driving means, so that the gap between the yoke and the armature is determined when the coil is energized. The fastening load can be applied and kept to a minimum that can be maintained. Therefore, the coil can be reduced in size, and as a result, the entire electric clutch can be made compact.

  Further, if the armature is spline-fitted on the first rotating shaft, the pressing surface and the mating plate are rotationally synchronized, and therefore the wear of the pressing surface and the mating plate in contact with the pressing surface can be prevented.

  In addition, if an elastic body is provided between the yoke and the bearing that rotatably supports the armature, the yoke and the armature are prevented from contacting when the coil is not energized, and the armature slides against the elastic body. Thus, the armature and the elastic body can be prevented from being worn.

Sectional drawing along an axis | shaft which shows the operation standby state of the electric clutch of this invention. FIG. Sectional drawing along an axis | shaft which shows the action | operation state of the electric clutch of this invention.

  An embodiment of the present invention will be described with reference to FIGS. However, the present invention is not limited to this embodiment. 1 to 3 is basically vertically symmetrical with respect to the axis X, only the upper half of the axis X is shown for convenience.

  As shown in FIG. 1, the electric clutch 10 of the present invention has a non-rotatable housing 12. Although a detailed description of the shaft support structure is omitted, the input shaft 22 that is the first rotation shaft is rotatably provided with respect to the housing 12, and torque from a drive system (not shown) is transmitted. On the other hand, an output shaft 32 that is a second rotating shaft is also rotatably supported by a bearing B provided in the housing 12.

  A plurality of mating plates 24 are spline-fitted on the inner peripheral surface of the input shaft 22. On the other hand, the friction plate 34 is spline-fitted on the outer peripheral surface of the hub 32a configured as a part of the output shaft 32 so as to be positioned between the mating plates 24. Yes. A friction material is affixed to both surfaces of the friction plate 34. In addition, what is necessary is just to determine the quantity of the other party plate 24 and the friction board 34 according to the transmission torque etc. which should be set. With such a configuration, the torque of the input shaft 22 is transmitted to the output shaft 32 when the mating plate 24 and the friction plate 34 are frictionally engaged.

  On the housing 12, a linear motion conversion mechanism 15 that is rotatable with respect to the housing 12 and is movable back and forth is attached. In the electric clutch 10, a screw is used as the linear motion conversion mechanism 15, but any other form may be used as long as the mechanism converts torque into linear motion.

  A yoke 16 is connected to the housing 12 via a linear motion conversion mechanism 15 and a snap ring S. Similarly to the linear motion converting mechanism 15, the yoke 16 is also provided so as to be movable back and forth with respect to the housing 12. In the electric clutch 10, the inner peripheral side of the yoke 16 is splined to the housing 12.

  The yoke 16 includes the coil 11, and is configured such that a magnetic field is generated in the yoke 16 when the coil 11 is energized. On the yoke 16, an armature 14 is pivotally supported by a bearing SB (specifically, a thrust bearing). Accordingly, the armature 14 is provided so as to be rotatable with respect to the housing 12 and capable of moving forward and backward. A gap C is provided between the armature 14 and the yoke 16.

  The armature 14 is provided with a pressing surface 14 a located on one side in the axial direction with respect to the mating plate 24. Specifically, the pressing surface 14 a is configured to face the mating plate 24 and to face the direction of the yoke 16 relative to the armature 14. Here, as shown in the drawing, the armature 14 may be configured to be spline-fitted to the input shaft 22 so as to rotate in synchronization with the input shaft 22. Thereby, when the pressing surface 14a contacts the mating plate 24, wear of the pressing surface 14a and the mating plate 24 can be prevented as compared with the case where the armature 14 is not splined to the input shaft 22.

  The electric clutch 10 includes a driving unit 18. The drive unit 18 may be any device that transmits torque to the linear motion conversion mechanism 15. For example, as illustrated in FIG. 2, the drive unit 18 has a protrusion 17 provided in the drive unit 18 in a recess 17 provided in the linear motion conversion mechanism 15. It can be set as the structure that the part 19 is fitting. Thereby, when the drive means 18 rotates, the torque is transmitted to the linear motion conversion mechanism 15. As the driving means 18, it is preferable to use a motor, particularly a stepping motor. This is because the amount of rotation transmitted to the linear motion converting mechanism 15 can be finely controlled by using the stepping motor, and therefore the advance / retreat distance of the armature 14 and the yoke 16 can be controlled in detail.

  Here, when the disc spring 13 is provided as an elastic body between the yoke 16 and the armature 14, it is possible to prevent the armature 14 from being moved by vibration and contacting the yoke 16 when the electric clutch 10 is not engaged. In particular, if the disc spring 13 is provided between the yoke 16 and the bearing SB, the armature 14 slides with respect to the disc spring 13 as compared with the case where the disc spring 13 is in direct contact with the armature 14. Abrasion can be prevented. In addition, it is also possible to apply things other than a disc spring as an elastic body.

  Next, an example of an operation method of the electric clutch 10 will be described. From the disengaged state of the electric clutch 10 shown in FIG. 1, first, the driving means 18 is rotated forward to transmit torque to the linear motion converting mechanism 15. Then, the linear motion conversion mechanism 15, the yoke 16, and the armature 14 move in one direction (right direction in the drawing) with respect to the housing 12. Gradually, the pressing surface 14a interlocking with the armature 14 approaches and comes into contact with the mating plate 24, and the mating plate 24 and the friction plate 34 come into close contact with each other. Thereafter, the coil 11 is energized, a magnetic field is generated in the yoke 16, and the armature 14 is attracted toward the yoke 16 to apply a load to the mating plate 24. Thus, the electric clutch 10 is engaged as shown in FIG. 3, and the mating plate 24 and the friction plate 34 are frictionally engaged, so that torque is transmitted from the input shaft 22 to the output shaft 32.

  In order to release the engaged state of the electric clutch 10, first, the energization of the coil 11 is stopped. Thereafter, the drive means 18 is reversed, and torque in the reverse rotation direction to that at the time of fastening is transmitted to the linear motion conversion mechanism 15. As a result, the linear motion conversion mechanism 15, the yoke 16, and the armature 14 move in the other direction (left direction in the drawing) with respect to the housing 12, so that the friction engagement state between the counterpart plate 24 and the friction plate 34 is released. The electric clutch 10 is in the state shown in FIG.

  Thus, according to the electric clutch 10, by controlling the driving means 18, the pressing surface 14a contacts the mating plate 24 and the mating plate 24 and the friction plate 34 are in close contact without depending on the energization of the coil 11. Since the armature 14 can be moved until it is done, it is easy to relieve the shock at the time of clutch engagement or disengagement, and it is easy to cope with slip control.

  Further, as described above, in the electric clutch 10, the coil 11 is configured such that the pressing surface 14 a contacts the mating plate 24 and the mating plate 24 and the friction plate 34 come into close contact, and then the friction engagement between the mating plate 24 and the friction plate 34. It is used to give the load necessary for Therefore, unlike the prior art, it is not necessary to set a large gap when the coil is energized between the armature and the yoke in consideration of future wear of the friction material during assembly. For this reason, it is possible to provide a gap C having a minimum interval for applying and maintaining a load necessary for frictional engagement between the mating plate 24 and the friction plate 34. Therefore, since the small coil 11 can be used, the electric clutch 10 can be reduced in size. It is also possible to achieve a good fastening load over the entire life of the product.

  Further, since the pressing surface 14a is brought into close contact with the mating plate 24, and the operation of controlling the driving means 18 to move away by a predetermined distance can be performed every time the clutch is released, regardless of the wear state of the friction material, that is, The optimal clutch clearance can always be set over the entire product life of the electric clutch 10.

  In the above description, an electric clutch is shown in which the yoke 16, the mating plate 24, and the friction plate 34 are arranged in parallel in the radial direction, and the yoke 16 and the driving means 18 are adjacent to each other. For example, the present invention can be applied to a configuration in which the yoke 16, the mating plate 24, and the friction plate 34 are arranged in parallel in the axial direction.

  As described above, according to the present invention, it is possible to provide a compact electric clutch that realizes a good fastening load throughout the life of a product and can cope with slip control.

DESCRIPTION OF SYMBOLS 10 Electric clutch 11 Coil 12 Housing 13 Elastic body 14 Armature 14a Pressing surface 15 Linear motion conversion mechanism 16 Yoke 18 Drive means 22 1st rotating shaft 24 Counterplate 32 Second rotating shaft 34 Friction plate C Air gap SB Bearing

Claims (3)

A non-rotatable housing;
A plurality of mating plates that are spline-fitted on the first rotating shaft;
A friction plate that is spline-fitted onto the second rotating shaft and disposed between the mating plates;
A linear motion conversion mechanism attached to the housing for converting torque into linear motion;
Drive means for transmitting torque to the linear motion conversion mechanism;
A yoke that is provided so as to be able to move forward and backward with respect to the housing in conjunction with the linear motion conversion mechanism;
An armature provided so as to be rotatable relative to the housing via a gap with respect to the yoke, and capable of moving forward and backward relative to the housing in conjunction with the linear motion conversion mechanism;
The armature is provided so as to face the mating plate and face the armature in the yoke direction, and has a pressing surface that approaches or separates from the mating plate in conjunction with the forward and backward movement of the armature. It is characterized by
Electric clutch.   The electric clutch according to claim 1, wherein the armature is spline-fitted onto the first rotating shaft. The electric clutch according to claim 1 or 2, wherein an elastic body is provided between a bearing that rotatably supports the armature, and the yoke and the bearing.

Images