JP2005110449A - Electric motor with speed reduction mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate power transmission from a worm wheel side, in an electric motor with a speed reduction mechanism that comprises a worm wheel engaging a worm cut on an end of a drive shaft. <P>SOLUTION: To make a worm 3c carved on one end 3b of a motor shaft 3 engage with a worm wheel 9 in the electric motor with the speed reduction mechanism, a rotating-in-one-direction clutch 10, which allows an end 3e at an end side farther than the worm 3c of the motor shaft 3 to rotate in the direction of closing a window G relatively to the motor shaft 3 but rotates with the motor shaft 3 with regard to the rotation in the direction of opening the window, and a friction plate 14, which is pressed to the clutch housing 11 of the clutch 10 by thrust displacement to the end side of the motor shaft 3 to regulate the rotations of the clutch 10, are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention belongs to the technical field of an electric motor with a speed reduction mechanism used as an actuator such as a power window.

In general, an electric motor with a speed reducing mechanism used as an actuator constituting an automobile power window is required to prevent the window from being opened by an external force. As a technique for this purpose, the reduction ratio between the worm and the worm wheel is used. A technique using a torque generated based on the above, a frictional force generated based on a displacement in the thrust direction of the drive shaft accompanying the meshing of the worm and the worm wheel has been proposed.
By the way, in an electric motor with a speed reducer that constitutes a power window, it is necessary to reduce idling torque and bearing loss in order to reduce output torque and improve efficiency. The technique will undermine this. For this reason, a method of providing a stopper for preventing rotation on the open side of the window on the shaft on the worm wheel side or using a resin material having a large friction coefficient as a thrust receiver for the motor shaft is proposed, but in the former case Since the device prevents rotation after deceleration, there is a problem that the device becomes large. In the latter case, friction force also acts during normal operation (operation that opens and closes the window with the output from the electric motor side). As a result, there is a problem that efficiency reduction cannot be suppressed.

As an improvement measure, a one-way rotation clutch is provided at the tip portion on the tip side from the worm engraving position of the motor shaft, and the motor shaft of the electric motor is mounted on the rotor whose rotation in one direction is restricted by the one-way rotation clutch. When the motor shaft is thrust displaced toward the rotor, rotation in one direction is restricted together with the rotor, and when the motor shaft is thrust displaced toward the base end, rotation is performed in one direction. When the motor shaft rotates in the other direction with the motor shaft displaced toward the rotor side, it is configured to be integrated with the rotor so that the output torque during normal operation of the electric motor can be reduced. It has been proposed not to impair the reduction or efficiency improvement.
Japanese Patent No. 3385237

  By the way, the conventional one is configured such that the base end portion of the rotor of the one-way rotation clutch and the tip end portion of the motor shaft are detachable based on the thrust displacement of the motor shaft. The conical fitting groove formed on the rotor base end surface and the conical fitting member provided on the front end surface of the motor shaft, and the motor shaft is caused by the frictional force between the fitting groove and the fitting member. And the one-way rotation clutch are configured to transmit power. For this reason, in this structure, not only a dedicated motor shaft having a fitting member formed on the front end surface of the motor shaft is required, but also the integration of the separation / contact portion (friction portion) is insufficient. Power transmission between the two-way clutch and the one-way rotary clutch is cut off and released when a force in the opening direction acts on the window. In order to achieve this, it is conceivable to increase the diameter of the rotor and the motor shaft. And there is a problem to be solved by the present invention.

The present invention has been made in view of the above-mentioned circumstances and has been created for the purpose of solving these problems. The invention of claim 1 is directed to a worm wheel having a worm carved at the tip of a drive shaft. In the electric motor with a speed reduction mechanism provided with a speed reduction mechanism that is engaged with each other, the tip of the drive shaft is allowed to rotate relative to the drive shaft in one direction but rotates in the other direction integrally with the drive shaft. The unidirectional rotation restricting means and the restricting means for restricting the rotation of the unidirectional rotation restricting means thrust-displaced to the front end side by meshing with the worm wheel are provided.
By doing so, the structure for restricting the drive shaft from rotating in the other direction from the worm wheel side is compact without increasing the diameter, and the operation is reliable, and the drive shaft is the same as the conventional one. The same configuration can be achieved, and the parts can be shared.
According to a second aspect of the present invention, in the first aspect of the present invention, the base end side of the drive shaft is provided with a deformation member that elastically deforms in response to thrust displacement toward the base end side of the drive shaft. Thus, the power transmission efficiency is not reduced while the backlash of the drive shaft is eliminated.
According to a third aspect of the present invention, in the first aspect, the base end of the drive shaft is allowed to rotate in the other direction of the drive shaft, but is configured to rotate integrally with the drive shaft in one direction of rotation. Direction rotation restricting means and second restricting means for restricting the rotation of the second one-way rotation restricting means thrust-displaced to the base end side by meshing with the worm wheel. Thus, the drive shaft can be configured not to rotate in any direction by an external force from the worm wheel side.

According to the first aspect of the present invention, it is possible to provide an electric motor with a reduction gear that is compact but has reliable power transmission, and the drive shaft can be configured in the same manner as in the past so that parts can be shared. Can be planned.
By setting it as invention of Claim 2, it can be set as the electric motor with a reduction gear that does not have backlash, and has good power transmission efficiency.
According to the invention of claim 3, it is possible to prevent the drive shaft from rotating in both rotational directions from the worm wheel side.

Next, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a drawing, and reference numeral 1 denotes an actuator that is provided in a window G on the side of the vehicle and constitutes a so-called power window. The actuator 1 includes a motor unit M that rotates at a predetermined rotational speed, the motor A reduction part D that reduces the rotation of the part M, and a reel part R that rotates while being reduced by the reduction part D are provided. A wire W connected to a window opening / closing mechanism C disposed on a vehicle window G is wound around the reel portion R of the actuator 1, and the reel is rotated in accordance with either forward or reverse rotation of the motor portion M. The part R rotates forward or backward, whereby one wire W is wound and the other wire W is unwound so that the window opening / closing mechanism C is actuated to open / close the window G. Is set.

The motor part M constituting the actuator 1 includes a bottomed cylindrical motor part casing 2, and a small-diameter cylindrical bearing cylinder part projecting to the base end side on the bottom surface of the motor part casing 2. 2a is formed, and the base end portion of the motor shaft (driving shaft of the present invention) 3 is rotatably supported by the bearing tube portion 2a via the bearing 3a. On the base end side of the motor shaft 3, a rotor 4 constituted by laminating a plurality of thin plate-like core members 4a and winding a coil 4b on the outer periphery thereof is integrally fitted. The outer peripheral surface of the rotor 4 is configured to be close to and opposed to the pair of permanent magnets 2b fixed to the inner peripheral surface of the motor casing 2.
Further, a commutator 5 located on the tip end side of the rotor 4 and electrically connected to the end of the coil 4 b is integrally fitted on the motor shaft 3, and the commutator 5 of the motor shaft 3 is integrally fitted. One end portion 3 b extending from the tip end surface toward the tip end side is arranged so as to protrude from the tube end portion 2 c of the motor portion casing 2. On the other hand, the cylinder end portion 2c of the motor section casing 2 is connected to the speed reduction section casing 7 constituting the speed reduction section D so that the cylinder opening is covered, and one end of the motor shaft protruding to the tip end side is configured. The part 3b is accommodated in the shaft interior part 7a of the speed reduction part casing 7 via the bearing 7b.
Reference numeral 8 denotes a brush stay 8 provided in the vicinity of the connecting portion between the motor section casing 2 and the speed reduction section casing 7, and the tip of the brush 8 a supported by the brush stay 8 is the outer peripheral surface of the commutator 5. It is set so as to be slidably contacted in an elastic manner.

A wheel interior portion 7c is integrally formed on one side portion of the shaft interior portion 7a of the speed reduction portion casing 7, and a worm wheel 9 is rotatably accommodated therein. The worm 3c engraved in the motor shaft one end 3b accommodated in the shaft interior portion 7a is set so as to mesh with it, and thereby the support shaft of the worm wheel 9 in a state where the output from the motor portion M is decelerated. 9a is set so as to be output, and thus the speed reduction mechanism is configured.
Further, the wheel interior portion 7c is integrally provided with a reel portion R. The reel portion R is provided with a winder (not shown) that rotates based on the rotation of the worm wheel support shaft 9a. Yes. As the motor unit M is driven, the winding shaft rotates correspondingly as the motor shaft 3 rotates forward or backward, and the wire W is wound or unwound based on the rotation. The window G is configured to open and close.

  As described above, the base end portion of the motor shaft 3 is supported by the bearing tube portion 2a via the bearing 3a. The bearing plate 2e is disposed on the tube bottom surface 2d of the bearing tube portion 2a. On the other hand, a steel ball 3d is arranged on the base end surface of the motor shaft 3 so as to be able to roll, and consideration is given to reducing the bearing loss of the motor shaft 3.

  On the other hand, as described above, the tip portion 3e, which is a tip side portion of the motor shaft one end portion 3b, is further supported by the shaft interior portion 7a via the bearing 7b. A bearing plate 7d is disposed on the tip surface of the shaft interior portion 7a. The one-way rotation clutch 10 constituting the one-way rotation restricting means in which the present invention is implemented is formed between the bearing plate 7d and the motor shaft tip portion 3e which is the tip side of the portion where the motor shaft worm 3c is engraved. Is provided. That is, as shown in FIGS. 3 and 4, the one-way rotary clutch 10 includes a bottomed cylindrical clutch housing 11 into which the motor shaft tip portion 3 e is fitted. Clutch grooves 11a whose groove bottom faces are inclined so that the groove depth changes are formed on the circumferential surface at four places in the circumferential direction. In each clutch groove 11a, a clutch roller 12 is rotatably mounted in a state of being sandwiched between the groove bottom surface and the outer peripheral surface of the motor shaft front end portion 3e. 13 is biased so as to be positioned on the deep side of the clutch groove 11a. When the motor shaft 3 rotates in one direction (in the direction of the arrow X), the one-way rotation clutch 10 rotates so that the clutch roller 12 is pushed to the groove deep side while receiving the urging force of the coil machine 13. Thus, the motor shaft 3 is set to be allowed to rotate (relatively rotatable) (clutch OFF state). On the other hand, when the motor shaft 3 rotates in the other direction (the direction of the arrow Y), the clutch roller 12 rolls against the biasing force of the coil machine 13 so that the clutch roller 12 is pushed to the shallow side of the groove. It is set so as to restrict further relative rotation of the shaft 3, and the clutch housing 11 of the one-way rotation clutch 10 and the motor shaft 3 are configured to rotate integrally (clutch ON state).

Further, a friction plate 14 corresponding to the restricting means of the present invention is provided between the cylinder bottom portion 11b of the clutch housing 11 and the bearing plate 7d in the speed reduction portion casing 7. As will be described later, the motor shaft 3 When the clutch housing cylinder bottom part 11b is pressed against the friction plate 14 as the motor shaft 3 is thrust-displaced to the front end side by engaging the worm wheel 9 and the worm wheel 9, the friction plate 14 is rubbed against the cylinder bottom part 11b. A force (friction) is applied to restrict the rotation of the clutch housing 11 (position direction rotation clutch 10).
In this configuration, when the motor shaft 3 rotates in the direction indicated by the arrow X in a state where the motor shaft 3 is thrust-displaced toward the tip and the clutch housing 11 is pressed against the friction plate 14, the clutch of the one-way rotating clutch 10 is used. Although the housing 11 is not subjected to rotation restriction by the friction plate 14 and the clutch housing 11 does not rotate, since the one-way rotary clutch 10 is in the clutch OFF state, the motor shaft 3 is relative to the clutch housing 11. It is set to rotate.
On the other hand, when the motor shaft 3 rotates in the arrow Y direction, the one-way rotation clutch 10 is in the clutch ON state, and the clutch housing 11 and the motor shaft 3 are in a state of rotating integrally. When the housing 11 is subjected to the rotation restriction by the friction plate 14, the motor shaft 3 is also set to be prevented from rotating due to the rotation restriction.

Next, the power transmission state (opening / closing operation of the window G) of the power transmission mechanism 10 of the present embodiment will be described with reference to FIG. Here, in FIG. 3, the actuator 1 closes the window G (up the window G) based on the rotation of the motor shaft 3 (drive shaft) in the arrow X direction and rotates in the arrow Y direction. Based on this, the window G is interlocked so as to open the window G (down the window G).
First, when the motor unit M is driven and the motor shaft 3 rotates in the direction of the arrow X to close the window G, the worm wheel 9 meshing with the motor shaft 3 rotates in the clockwise direction. Based on this, the motor shaft 3 is thrust displaced in the direction of arrow A (the tip side). At this time, the one-way rotation clutch 10 at the tip of the motor shaft 3 is subjected to rotation restriction because the clutch housing 11 is pressed against the friction plate 14, but since the one-way rotation clutch 10 is in the clutch OFF state, Rotation in the direction of arrow X is allowed, whereby the motor shaft 3 is set to rotate relative to the one-way rotation clutch 10 (rotation in the direction of arrow X) and the window G is closed. Has been.

  On the other hand, when the motor unit M is driven and the motor shaft 3 rotates in the direction of the arrow Y to open the window G, the worm wheel 9 meshing with the motor shaft 3 rotates counterclockwise. Based on this, the motor shaft 3 is thrust displaced in the direction of arrow B (base end side). At this time, the one-way rotary clutch 10 at the tip of the motor shaft 3 is in the clutch ON state, but the clutch housing 11 and the friction plate 14 are separated from each other. Thus, the motor shaft 3 is set so that the motor shaft 3 is allowed to rotate integrally with the one-way rotation clutch 10 in the arrow Y direction and the window G is opened.

On the other hand, the case where the load which tries to push up and push down the window G with the force from the outside acts is demonstrated.
First, when a load is applied to push up (shut down) the window G by an external force, the worm wheel 9 rotates in the clockwise direction so that the motor shaft 3 is moved to the arrow through the mutual meshing. A force for rotating in the X direction acts, and a force for thrust displacement of the motor shaft 3 in the arrow B direction (base end side) acts. In this case, the one-way rotation clutch 10 is in a clutch-off state with respect to the rotation direction of the motor shaft 3, the motor shaft 3 is rotatable relative to the clutch housing 11, and the one-way rotation clutch 10 is a friction plate. No friction from 14 is received. Therefore, the motor shaft 3 can freely rotate in the direction of the arrow X, and the window G can be closed based on an external force.

  On the other hand, when a load is applied to open (open) the window G by an external force, the worm wheel 9 rotates counterclockwise, thereby causing the motor shaft 3 to move through the mutual meshing. A force for rotating in the arrow Y direction acts, and a force for thrust displacement of the motor shaft 3 in the arrow A direction (tip end side) acts. In this case, the one-way rotation clutch 10 is in a clutch-on state with respect to the rotation direction of the motor shaft 3, the motor shaft 3 is integrated with the clutch housing 11, and the clutch housing 11 is frictioned by the friction plate 14. In response to the rotation is restricted. For this reason, the motor shaft 3 is configured such that rotation in the arrow Y direction is restricted, and the window G is not opened by an external force.

In the present embodiment configured as described above, when the window G is opened and closed based on the driving of the motor unit M1, the opening of the window G based on the external force is based on the engagement between the worm wheel 9 and the motor shaft 3. The shaft 3 is prohibited from being thrust when it is thrust-displaced toward the tip end and subject to rotation restriction by a one-way rotation clutch 10 provided at the tip of the motor shaft 3. In this configuration, the rotation of the motor shaft 3 is not directly restricted by the one-way rotation clutch 10, but the clutch housing 11 of the one-way rotation clutch 10 provided on the motor shaft 3 is pressed against the friction plate 14. The rotation is restricted based on the friction generated by the above. As a result, based on the thrust displacement of the shaft body, the separation and connection between the rotor on the one-way rotation clutch side and the shaft body is switched, and based on this, the motor shaft is controlled like the conventional one that restricts the rotation of the shaft body. There is no need to make 3 a special specification, and a motor shaft having a conventional structure can be used as it is, and the members can be shared. In addition, it is possible not only to avoid the trouble of dividing the motor shaft 3 into two parts, but to avoid uncertainties in power transmission based on the instability of these integrations, and to improve the reliability of power transmission. There is no need to increase the diameter of the motor shaft 3 in order to increase the size, so that compactness is not impaired.
Further, in this configuration, since the rotation restriction of the motor shaft 3 is performed between the clutch housing 11 and the friction plate 14 of the one-way rotation clutch 10, stable power transmission can be achieved and transmission efficiency is improved. In addition, the operating noise can be reduced, and the size of the friction can be adjusted according to the usage state of the actuator 1.

Of course, the present invention is not limited to the above-described embodiment, and may be the second embodiment shown in FIG.
In this configuration, the cylinder depth of the clutch housing 15a of the one-way rotary clutch 15 is secured to be large, and the outer periphery of the clutch housing 15a is supported by the shaft interior portion 7a of the speed reduction portion casing 7 via a bearing 15b. ing. As a result, the overall length of the motor shaft 3 can be made shorter than in the first embodiment in which the base end portion of the motor shaft 3 is supported on the shaft interior portion 7a via the bearing 7b. This is effective when the space for arranging the actuator 1 cannot be made long in the axial direction.

Moreover, it can also comprise like 3rd embodiment shown in FIG.
This is configured in the same manner as in the first embodiment, and includes a bearing plate 2e that abuts on a steel ball 3d provided on the base end face of the motor shaft 3, and a cylinder of the motor casing casing cylinder 2a. Between the bottom surface 2d, an elastically deformable buffer body 16 made of, for example, rubber or the like is provided. In the configuration as described above, when the motor shaft 3 rotates in the direction of the arrow Y based on the driving of the motor unit M, and the motor shaft 3 undergoes thrust displacement toward the base end side, the buffer body 16 is elastically deformed. By doing so, the thrust displacement is set. Accordingly, when the thrust displacement is performed, the friction of the friction plate 14 to the clutch housing 11 is reduced, and the work efficiency can be improved. Further, in the first embodiment, since the thrust movement of the drive shaft (motor shaft 3) is allowed, it is necessary to form a slight gap in advance, and the play in the thrust direction is inevitably generated. However, when the shock absorber 16 is interposed, rattling is eliminated in the absence of thrust displacement, and in the event of thrust displacement, the thrust displacement can be received by elastic deformation, eliminating thrust play. However, the excellent actuator 1 that can ensure the movement in the thrust direction can be obtained.

Furthermore, such a one-way rotation restricting means and a restricting means for restricting the rotation of the one-way rotation restricting means are not only provided at the distal end of the shaft body as in the respective embodiments, but also the distal end and the proximal end. It can also be set as the structure provided in both. In this case, the second one-way rotation restricting means provided on the base end side is opposite to the one-side rotation restricting means (first one-way rotation restricting means) on the distal end side, that is, rotation in the other direction is not performed. Although restricted, the one that rotates integrally with the drive shaft is used for rotation in one direction. By configuring in this way, the window G is configured not to move in either the opening or closing direction by an external force. Can do.
In this case, the second restriction means on the base end side is the same as the restriction means (first restriction means, which is the friction plate in the first embodiment) provided on the distal end side. Can be used.

It is a side view explaining the outline of a power window structure. It is a partial cross section side view of an actuator. It is a side view explaining the principal part of an actuator. It is LL sectional drawing in FIG. It is a side view explaining the principal part of the actuator in 2nd embodiment. It is a side view explaining the principal part of the actuator in 3rd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 2 Motor part casing 2e Bearing plate 3 Motor shaft 3d Steel ball 7 Deceleration part casing 7a Shaft interior part 9 Worm wheel 10 One-way rotation clutch 11 Clutch housing 12 Clutch roller 13 Coil machine 14 Friction plate

Claims (3)

  In an electric motor with a speed reduction mechanism provided with a speed reduction mechanism in which a worm engraved at the tip of the drive shaft is engaged with a worm wheel, relative rotation in one direction relative to the drive shaft is allowed at the tip of the drive shaft However, there is a unidirectional rotation restricting means configured to rotate integrally with the drive shaft in rotation in the other direction, and a restricting means for restricting the rotation of the unidirectional rotation restricting means thrust displaced to the front end side by meshing with the worm wheel. An electric motor with a reduction mechanism provided.   2. The electric motor with a speed reduction mechanism according to claim 1, wherein a deformation member that elastically deforms upon receiving a thrust displacement toward the proximal end of the drive shaft is provided on the proximal end side of the drive shaft.   2. The second unidirectional rotation restricting means configured to allow rotation of the drive shaft in the other direction, but to rotate integrally with the drive shaft in one direction rotation, at the base end of the drive shaft, and a worm An electric motor with a speed reduction mechanism provided with a second restricting means for restricting rotation of the second one-way rotation restricting means thrust displaced to the base end side by meshing with the wheel.

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