JP2020025421A - Power window motor unit - Google Patents

Abstract

To provide a motor unit for a power window capable of achieving both reverse resistance and starting performance at high uniformity while achieving miniaturization and weight reduction.SOLUTION: An output shaft 8a of a motor 8 is extended to a left side in a worm accommodation chamber 7 of a body casing 2, and a worm 9 at a tip end is meshed with a worm wheel 6. A magnet 15a of a rotation angle sensor 15 is fixed to an extended portion of the output shaft 8a via a holder 16, a bimorph type piezoelectric actuator 18 is arranged in the worm accommodation chamber 7, and a friction member 20 is stuck to its free end. While a regulator is stopped, the piezoelectric actuator 18 is not energized, a friction member 20 is brought into pressure contact with an outer peripheral surface of the holder 16, a rotational resistance is given to the output shaft 8a of the motor 8, and inversion resistance is secured. When the regulator is operated, the friction member 20 is separated from the outer peripheral surface of the holder 16 by energizing the piezoelectric actuator 18, and the rotation of the output shaft 8a is allowed to ensure startability.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power window motor unit, and more particularly, to a power window motor unit that is incorporated in a power window regulator and functions as a power source.

  2. Description of the Related Art A power window mounted on a vehicle is configured such that a regulator (elevating mechanism) installed in a door is operated by a driving force of a motor unit to elevate and lower the window. When the power window is not operated, when the regulator is stopped, the so-called reversing resistance is used to keep the intended lifting position against the weight of the window and to prevent the window from being opened from the outside for theft etc. Is required for the regulator.

  In order to assist the reversing resistance required for such a power window, a countermeasure for ensuring the reversing resistance may be taken in a power window motor unit as a power source in some cases. For example, in the techniques described in Patent Literatures 1 to 3, the tooth surface of a worm or a worm wheel for transmitting the driving force of a motor is intentionally roughened, and the gear efficiency is reduced due to an increase in rotational resistance to obtain reversal resistance. ing.

JP-A-04-138049 JP 2003-097671 A JP 2006-177426 A

  By the way, in order to realize a good operation feeling of the power window, it is required to have a startability for quickly raising and lowering the window in response to a switch operation. When the gear efficiency is reduced as in the technologies of Patent Documents 1 to 3, the reduction in the gear efficiency contributes to ensuring the reversal resistance while the regulator is stopped, but the reduction in the gear efficiency starts when the regulator operates. It acts in the direction that hinders the sex. As a result, the techniques of Patent Documents 1 to 3 make it difficult to achieve both reversal resistance and startability, and require another measure such as enlarging the motor in order to secure startability. There was a problem that the demand for weight reduction could not be met.

  The present invention has been made to solve such a problem, and an object of the present invention is to achieve a motor unit having a small size and a light weight, and at the same time, achieve a high level of reversal resistance and startability. To provide a motor unit for a power window.

  In order to achieve the above object, a motor unit for a power window according to the present invention includes a worm fixed to the output shaft of the motor, wherein the output shaft of the motor is disposed so as to intersect with the axis of a worm wheel having the output shaft. In a power window motor unit that is meshed with the worm wheel, a brake provided on any rotating portion of a power transmission path from an output shaft of the motor to the output shaft of the worm wheel through the worm. A ring, a piezoelectric actuator arranged with an engagement portion facing the brake ring, and energization switching means for switching an energization state of the piezoelectric actuator (claim 1).

  According to the power window motor unit configured as described above, the energization state of the piezoelectric actuator is switched by the energization switching means. Then, according to the energized state of the piezoelectric actuator, when the engagement portion engages with the brake ring, rotational resistance is imparted to ensure reverse rotation resistance, and when the engagement of the engagement portion with the brake ring is released, activation occurs. Nature is secured. As a result, the reversal resistance and the startability are compatible at a high level, and the startability can be secured without increasing the size of the motor.

  As another aspect, the piezoelectric actuator disengages the engagement portion with the brake ring during energization while applying the rotation resistance by engaging the engagement portion with the brake ring when not energized, It is preferable that the energization switching means be configured to keep the piezoelectric actuator in a non-energized state when the motor is not energized, and to switch the piezoelectric actuator to an energized state when the motor is energized (claim 2).

  According to the power window motor unit configured as described above, when the motor is not energized (while the regulator is stopped), the piezoelectric actuator is kept in the non-energized state, the engagement portion engages with the brake ring, and the motor During energization (during operation of the regulator), the piezoelectric actuator is switched to the energized state, and the engagement of the engagement portion with the brake ring is released.

In another aspect, the piezoelectric actuator is a bimorph type piezoelectric actuator, and is preferably configured such that the engaging portion provided at a free end is opposed to an outer peripheral surface of the brake ring (Claim 3). .
According to the power window motor unit configured as described above, the engaging portion is provided at the free end of the bimorph type piezoelectric actuator, and the engaging portion engages with the outer peripheral surface of the brake ring when not energized, and engages when energized. The engagement of the parts is released.

As another aspect, it is preferable that the engaging portion of the piezoelectric actuator is a friction member made of a high friction material (claim 4).
According to the power window motor unit configured as described above, when the piezoelectric actuator is not energized, the friction member made of a high friction material is pressed against the outer peripheral surface of the brake ring to impart rotational resistance.

As another aspect, a large number of irregularities are arranged in the circumferential direction on the outer peripheral surface of the brake ring, and the engaging portion of the piezoelectric actuator has irregularities that can mesh with any of the multiple irregularities on the outer peripheral surface. Preferably, it is a meshing member (claim 5).
According to the power window motor unit configured as above, when the piezoelectric actuator is not energized, the unevenness of the meshing member meshes with the unevenness of the outer peripheral surface of the brake ring, and the rotation is regulated by the geometrical meshing without relying on friction. Therefore, more reliable reversal resistance is achieved.

  As another aspect, an output shaft of the motor is extended toward the worm wheel side in a worm housing chamber formed in the main body casing, and the extension portion is provided with the brake ring and fixed to a distal end. Preferably, the worm is meshed with the worm wheel, and the piezoelectric actuator is disposed in the worm housing so that the engaging portion faces the brake ring (claim 6).

According to the power window motor unit configured as described above, the output shaft is extended toward the worm wheel in order to engage the worm fixed to the output shaft of the motor with the worm wheel. A piezoelectric actuator is disposed in the resulting worm receiving chamber, and a brake ring is provided at an extended portion of the output shaft. Accordingly, the motor unit is provided with a function of resistance to reversal without affecting the outer dimensions of the main body casing.
Further, even if a downward force on the window acts on the worm wheel via the regulator, the worm is originally unlikely to be rotated by the self-locking action. Since a rotational resistance is imparted to the worm and, consequently, the output shaft of the motor, strong reversal resistance is realized.

As still another aspect, the apparatus further includes a magnet attached to a portion where the output shaft of the motor extends via a holder, and a rotation angle sensor including a sensor body that outputs a rotation angle signal with rotation of the magnet. It is preferable that the holder functions as the brake ring so that an engagement portion of the piezoelectric actuator can be engaged (claim 7).
According to the power window motor unit configured as described above, the holder of the existing rotation angle sensor is used as the brake ring to be engaged by the engagement member.

In another aspect, the piezoelectric actuator is disposed at a position close to the worm wheel, and the worm wheel functions as the brake ring and an engagement portion of the piezoelectric actuator can be engaged. Is preferable (claim 8).
According to the power window motor unit configured as described above, the worm wheel functions as a brake ring, and the engaging portion of the piezoelectric actuator is engaged.

As still another aspect, the energization switching means is a bridge circuit interposed between the motor and the piezoelectric actuator, and the energization switching means is provided when the motor is energized in both forward and reverse directions for raising and lowering a power window. It is preferable that the piezoelectric actuator is configured to be energized in the same direction (claim 9).
According to the power window motor unit configured in this manner, the piezoelectric actuator is energized in the same direction when the motor is energized in either the forward or reverse direction, simply by interposing a bridge circuit between the motor and the piezoelectric actuator. The engagement of the engagement portion with the brake ring can be released.

  ADVANTAGE OF THE INVENTION According to the motor unit for power windows of this invention, while achieving size reduction and weight reduction of a motor unit, reversal resistance and startability can be made compatible with high dimension.

It is a perspective view showing the motor unit for power windows of an embodiment. It is sectional drawing which similarly shows a motor unit. FIG. 4 is a partially enlarged view showing the piezoelectric actuator when it is at a regulated position without being energized. It is the elements on larger scale which show the piezoelectric actuator switched to the cancellation | release position by energization. FIG. 5 is a sectional view taken along line VV of FIG. 3. It is an electric circuit diagram of the motor unit for power windows. FIG. 6 is a cross-sectional view corresponding to FIG. 5 showing another example in which a meshing member having irregularities is attached to a free end of a piezoelectric actuator.

Hereinafter, an embodiment of a power window motor unit embodying the present invention will be described.
FIG. 1 is a perspective view showing a motor unit for a power window of the present embodiment, and FIG. 2 is a sectional view showing the motor unit.

  The main body casing 2 of the motor unit 1 is made of a synthetic resin material, is formed so that a wheel housing chamber 3 having a circular shape in a front view is opened forward, and mounting brackets are provided at three places around the main body casing 2. 4 are integrally formed. The wheel housing 3 has a predetermined thickness in the front-rear direction, and the opening is closed by the front cover 5. A worm wheel 6 is rotatably supported in the wheel accommodating chamber 3 around an axis Cw extending in the front-rear direction, and an output shaft 6a of the worm wheel 6 penetrates through the front cover 5 and protrudes forward.

  A worm housing 7 is formed from the right side above the wheel housing 3 of the main body casing 2, and the interior thereof communicates with the upper part of the wheel housing 3 located below. A motor 8 is attached to the opening of the worm housing 7 from the right side orthogonal to the axis Cw of the worm wheel 6, and the output shaft 8 a of the motor 8 is located on the left side along the axis Cm (the worm) in the worm housing 7. The worm 9 extends toward the worm wheel 6 and is fixed to the tip of the output shaft 8a.

  The motor unit 1 is assembled via a mounting bracket 4 to a regulator installed in a vehicle door (not shown), and the output shaft 6a of the worm wheel 6 is connected to the regulator. When the output shaft 8a of the motor 8 rotates in a predetermined direction, the rotation is decelerated via the worm 9 and the worm wheel 6 and transmitted to the regulator from the output shaft 6a. I do.

  As shown in FIG. 2, a substrate accommodating chamber 11 is integrally formed above the worm accommodating chamber 7 of the main body casing 2, and a control substrate 12 disposed therein is connected to the motor 8 via terminals (not shown) through terminals. While being electrically connected, it is also electrically connected to a connector 14 provided on one side of the substrate accommodating chamber 11. When the motor unit 1 is mounted on the regulator, a connector from the vehicle side is connected to the connector 14, and electric power for driving the motor is supplied to the control board 12 according to the operation of the window elevating switch 22 (shown in FIG. 6). Is entered.

  In the worm receiving chamber 7, a cylindrical magnet 15a is fixed to an extension of the output shaft 8a of the motor 8, and the sensor body 15b (shown in FIGS. 3 and 4) faces the outer peripheral surface of the magnet 15a. ) Is disposed and electrically connected to the control board 12. The rotation angle sensor 15 is configured by the magnet 15a and the sensor main body 15b, and a rotation angle signal is input from the sensor main body 15b to the control board 12 by a change in magnetic force of the magnet 15a that rotates together with the output shaft 8a of the motor 8.

  The magnet 15a made of a sintered material has poor toughness. For example, when the magnet 15a is press-fitted for fixing to the output shaft 8a of the motor 8, it is broken. Therefore, the magnet 15a is indirectly fixed to the output shaft 8a by pressing the holder 16 bonded to the magnet 15a into the output shaft 8a.

  By the way, in order to assist the reversing resistance required for the power window, in the motor units of Patent Documents 1 to 3, the gear efficiency is lowered by intentionally roughening the worm or the worm wheel tooth surface, thereby reducing the reversing resistance. Have gained. However, as described in [Problems to be Solved by the Invention], when the gear efficiency is reduced, there is a problem that the startability, which is indispensable for a good power window operation feeling, is reduced.

  In view of such a problem, the present inventor has proposed that the countermeasures for roughening the tooth surface of Patent Documents 1 to 3 always reduce gear efficiency regardless of the stop and operation of the regulator, and act in a disadvantageous direction with respect to startability. We paid attention to the point. That is, if the gear efficiency and, consequently, the rotational resistance of the gear can be switched in accordance with the operation / stop of the regulator, the rotational resistance is applied during stoppage of the regulator requiring reverse rotation resistance, and the startability is required. At the time of operation of the regulator (especially at the start of the rising of the window), the application of the rotation resistance can be stopped, and as a result, both the reversal resistance and the startability can be achieved at a high level.

Based on the above knowledge, the present invention provides a bimorph-type piezoelectric actuator 18 (hereinafter, simply referred to as a piezoelectric actuator) that imparts rotational resistance in accordance with the energized state of the motor 8, and details thereof will be described below. explain.
FIG. 3 is a partially enlarged view showing the piezoelectric actuator 18 when it is at a regulated position without being energized, FIG. 4 is a partially enlarged view showing the piezoelectric actuator 18 switched to a release position by being energized, and FIG. It is sectional drawing.

  In the present embodiment, a rotational resistance is applied to the output shaft 8a of the motor 8, and the piezoelectric actuator 18 is disposed in the worm housing 7 as shown in FIG. As is well known, the bimorph-type piezoelectric actuator 18 is configured by adhering two piezoelectric elements 18a with an intermediate electrode 18b also serving as a shim sandwiched therebetween, and formed on the surface side of the intermediate electrode 18b and each piezoelectric element 18a. The piezoelectric element 18a expands and contracts in the opposite direction by a voltage applied between the piezoelectric actuator 18 and the front surface electrode 18c, thereby causing the entire piezoelectric actuator 18 to warp.

  As shown in FIGS. 3 to 5, the piezoelectric actuator 18 has a fixed end fixed to an upper wall in the worm receiving chamber 7 via a base member 19, and a free end extending rightward to the rotation angle sensor 15. It is located directly above the holder 16. A friction member 20 (engaging portion) is attached to the lower surface of the free end of the piezoelectric actuator 18 so as to face the outer peripheral surface of the holder 16, and the friction member 20 is made of a material having a high friction coefficient (high friction material). For example, it is made of silicon rubber or urethane.

  The holder 16 has a cylindrical shape about the axis Cm and functions as the brake ring of the present invention. The lower surface of the friction member 20 has an arcuate cross section so as to correspond to the outer peripheral surface of the brake ring 16, and the entire lower surface can be pressed against the outer peripheral surface of the brake ring 16.

  As shown in FIG. 3, the non-energized piezoelectric actuator 18 displaces its free end downward to press the friction member 20 against the outer peripheral surface of the brake ring 16, and the output shaft 8a of the motor 8 reduces the rotational resistance. The rotation has been hindered (hereinafter, referred to as a restricted position). As shown in FIG. 4, the piezoelectric actuator 18 when energized displaces the free end upward to separate the friction member 20 from the outer peripheral surface of the brake ring 16, and the output shaft 8a of the motor 8 reduces the rotational resistance. Rotation is allowed without receiving (hereinafter, referred to as a release position).

FIG. 6 is an electric circuit diagram of the power window motor unit 1.
The window up / down switch 22 is switched between a neutral position, an up position, and a down position, and power from the vehicle-mounted battery 23 is input to the control board 12 via the connector 14 in accordance with the switch operation. The input electric power is supplied to the motor 8 via the control board 12, and the driving of the motor 8 activates the regulator to stop, raise or lower the window. In addition, the control board 12 recognizes the window elevating position based on the rotation angle signal from the rotation angle sensor 15 and automatically stops the motor 8 at the fully closed position or the fully opened position.

The above configuration is not different from a general power window. Next, a configuration for driving the piezoelectric actuator 18 will be described.
As described above, when the regulator is stopped, reverse rotation resistance is required. Therefore, as shown by a solid line in FIG. 6, it is necessary to switch the piezoelectric actuator 18 to the regulation position to apply a rotational resistance to the output shaft 8a of the motor 8. There is. On the other hand, when the regulator is activated, that is, during start-up and descent of the window, startability is required. Therefore, as shown by the phantom line in FIG. It is necessary to allow rotation of the shaft 8a.

  Since the stop and operation of the regulator are interlocked with the switching of the energization state of the motor 8, if the power supplied to the motor 8 is also supplied to the piezoelectric actuator 18, the stop and operation of the regulator are interlocked with the stop and operation of the regulator. The operating state can be switched. However, even when the regulator is operating, the rotation direction of the motor 8 and, consequently, the energizing direction are reversed between when the window is raised and when the window is lowered, and the piezoelectric actuator 18 cannot be brought to the release position in either energizing direction. Therefore, in the present embodiment, a single-phase bridge type full-wave rectifier circuit 24 (current switching means of the present invention, hereinafter simply referred to as a bridge circuit) is interposed between the motor 8 and the piezoelectric actuator 18 to provide a piezoelectric circuit. The direction of energization to the actuator 18 is unified.

  The bridge circuit 24 is configured as a diode bridge connecting four diodes 24a, and is connected in parallel to the motor 8 by connecting a pair of input terminals 24b to both input terminals of the motor 8, respectively. The positive output terminal 24c of the bridge circuit 24 is connected to the surface electrode 18c of the piezoelectric actuator 18, and the negative output terminal 24d is connected to the intermediate electrode 18b of the piezoelectric actuator 18.

  At the neutral position of the elevation switch 22, the regulator is stopped because the motor 8 is not energized, and the window is maintained at the intended elevation position from fully open to fully closed. Also, the piezoelectric actuator 18 is not energized, and is kept at the regulated position indicated by the solid line in FIG. 6, and the output shaft 8a of the motor 8 is prevented from rotating due to rotational resistance. Accordingly, the motor unit 1 exerts the reversal resistance and acts on the regulator, which contributes to maintaining the current window elevation position.

  At the ascending position of the lift switch 22, a current flows in a direction indicated by a solid arrow in FIG. For this reason, a positive potential is generated at the positive output terminal 24c of the bridge circuit 24, and a negative potential is generated at the negative output terminal 24d, so that the piezoelectric actuator 18 is energized and the release indicated by a virtual line in FIG. Switch to position. At the same time, the motor 8 rotates forward and the window is raised by the regulator. However, since the piezoelectric actuator 18 is at the release position, the output shaft 8a of the motor 8 rotates without receiving rotational resistance and exhibits good startability. Is done. As a result, the window rises quickly, and particularly, the start of the upward movement is promptly made in response to the switch operation, so that a good operation feeling of the power window can be realized.

  At the lower position of the lift switch 22, a current flows in the direction shown by the broken arrow in FIG. Similarly to the ascending position, a positive potential is generated at the positive output terminal 24c of the bridge circuit 24, and a negative potential is generated at the negative output terminal 24d, so that the piezoelectric actuator 18 is energized in the same direction as when ascending. It is switched to the release position. At the same time, the motor 8 rotates in the reverse direction and the window is lowered by the regulator. However, since the piezoelectric actuator 18 is at the release position, the motor 8 exhibits good startability. As a result, the window descends quickly, and a good operation feeling of the power window can be realized.

  As described above, according to the power window motor unit 1 of the present embodiment, the rotation resistance is applied to the output shaft 8a of the motor 8 by the piezoelectric actuator 18 during the stop of the regulator that requires reverse rotation resistance, and the startability is improved. During the required operation of the regulator, the application of the rotational resistance to the output shaft 8a is stopped. For this reason, reversal resistance and startability can be achieved at a high level, and startability can be secured without increasing the size of the motor 8, so that the size and weight of the motor unit 1 can be reduced.

  In addition, a piezoelectric actuator 18 is provided in the worm housing 7 in order to impart rotational resistance to the output shaft 8a of the motor 8, and as can be seen from FIG. 2, the worm housing 7 is a dead space that is not used at all. It is. That is, the positional relationship between the worm wheel 6 and the motor 8 is determined from the layout of each component on the main body casing 2, and the worm 9 fixed to the tip of the output shaft 8 a of the motor 8 is engaged with the worm wheel 6. It is necessary to extend the output shaft 8a to the left. The space formed as a result is the worm housing chamber 7, in which only the output shaft 8a is inserted.

In the present embodiment, the piezoelectric actuator 18 is provided by utilizing the worm housing chamber 7 which is a dead space, and furthermore, as a brake ring to be pressed against the friction member 20 at its free end, an existing rotation angle is used. The holder 16 of the sensor 15 is used. As a result, the motor unit 1 can be provided with a reversing resistance function without affecting the outer dimensions of the main body casing 2 at all, which also greatly contributes to a reduction in size and weight.
Note that the holder 16 does not necessarily need to be a brake ring, and a brake ring may be provided separately from the holder 16. Further, the position where the friction member 20 presses the brake ring 16 is not limited to the outer peripheral surface, and may be pressed against the side surface of the brake ring 16, for example.

  Furthermore, providing rotation resistance to the output shaft 8a of the motor 8 also leads to enhancement of the reversal resistance. Since the self-locking action acts on the engagement between the worm 9 and the worm wheel 6, even if a downward force on the window acts on the worm wheel 6 via the regulator, the worm 9 is hard to rotate. As described above, since the worm 9 which is originally hardly affected by the force transmitted from the window side and thus the output shaft 8a of the motor 8 is provided with a rotational resistance, it is compared with a case where the worm wheel 6 is provided with a rotational resistance. Thus, stronger reversal resistance can be realized with the same driving force of the piezoelectric actuator 18.

  However, it is not always necessary to impart rotational resistance to the output shaft 8a of the motor 8, and if it is a rotating part of the power transmission path from the output shaft 8a of the motor 8 to the output shaft 6a of the worm wheel 6 via the worm 9 Alternatively, the brake ring 16 may be provided at any location to impart rotational resistance. For example, rotation resistance may be given to the worm wheel 6 as described above. In this case, the piezoelectric actuator 18 is disposed in the vicinity of the worm wheel 6, the worm wheel 6 functions as a brake ring, and the friction member 20 at the free end of the piezoelectric actuator 18 is pressed.

  Further, since the friction member 20 pressed against the outer peripheral surface of the brake ring 16 by the piezoelectric actuator 18 is made of a high friction material such as silicon rubber or urethane, it is made of metal or the like at the time of pressure contact (in other words, the lifting switch 22). No collision sound is generated when the operation is stopped). Therefore, good quietness in the vehicle compartment can be maintained.

  The engagement member of the present invention is not limited to the friction member 20, and may be configured as shown in FIG. 7, for example. In this alternative example, a large number of irregularities are arranged in the circumferential direction on the entire outer periphery of the brake ring 16, and a meshing member 31 having, at the free end of the piezoelectric actuator 18, irregularities that can mesh with any of the large number of irregularities of the brake ring 16. (Engaging portion) is attached. When the piezoelectric actuator 18 is not energized, the unevenness of the meshing member 31 meshes with the unevenness of the outer peripheral surface of the brake ring 16, and the rotation is regulated by the geometrical meshing without relying on friction, so that more reliable reversal resistance is achieved. it can.

  When the worm wheel 6 functions as a brake ring as described above, the teeth of the worm wheel 6 may be meshed with the unevenness of the meshing member 31. The material of the meshing member 31 may be made of metal, or may be made of silicon rubber or urethane as in the friction member 20 of the embodiment. In the latter case, it is possible to prevent a collision sound at the time of meshing and realize good quietness in the vehicle interior.

  The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, although the bimorph type piezoelectric actuator 18 is used in the above-described embodiment, a laminated type piezoelectric actuator may be used instead.

Reference Signs List 1 motor unit 2 main body casing 6 worm wheel (brake ring)
6a Output shaft 7 Worm storage chamber 8 Motor 8a Output shaft 9 Worm 15 Rotation angle sensor 15a Magnet 15b Sensor body 16 Holder (brake ring)
18 Piezoelectric actuator 20 Friction member (engagement part)
24 Bridge circuit (energization switching means)
31 meshing member (engaging part)

Claims (9)

An output shaft of a motor is disposed so as to intersect with an axis of a worm wheel having an output shaft.In a motor unit for a power window, a worm fixed to the output shaft of the motor is meshed with the worm wheel.
A brake ring provided on any rotating part of a power transmission path from the output shaft of the motor to the output shaft of the worm wheel via the worm;
A piezoelectric actuator arranged with the engagement portion facing the brake ring,
A motor unit for a power window, comprising: an energization switching unit that switches an energization state of the piezoelectric actuator. When the piezoelectric actuator is not energized, the engagement portion is engaged with the brake ring to impart rotational resistance, while when energized, the engagement of the engagement portion with the brake ring is released,
The power window motor according to claim 1, wherein the energization switching means keeps the piezoelectric actuator in a non-energized state when the motor is not energized, and switches the piezoelectric actuator to an energized state when the motor is energized. unit. 3. The piezoelectric actuator according to claim 1, wherein the piezoelectric actuator is a bimorph type piezoelectric actuator, and the engagement portion provided at a free end is configured to face an outer peripheral surface of the brake ring. The power window motor unit as described. The motor unit for a power window according to any one of claims 1 to 3, wherein the engagement portion of the piezoelectric actuator is a friction member made of a high friction material. On the outer peripheral surface of the brake ring, a number of irregularities are arranged in the circumferential direction,
4. The power window according to claim 1, wherein the engaging portion of the piezoelectric actuator is a meshing member having irregularities that can mesh with any of the plurality of irregularities on the outer peripheral surface. 5. Motor unit. The output shaft of the motor extends toward the worm wheel in a worm receiving chamber formed in the main body casing, and the extended portion is provided with the brake ring, and the worm fixed to the tip is the worm wheel. Meshed with
The power window motor according to any one of claims 1 to 5, wherein the piezoelectric actuator is disposed in the worm receiving chamber, and the engaging portion faces the brake ring. unit. A magnet attached to the extension of the output shaft of the motor via a holder, and a rotation angle sensor including a sensor main body that outputs a rotation angle signal with rotation of the magnet,
The power window motor unit according to claim 6, wherein the holder functions as the brake ring, and an engagement portion of the piezoelectric actuator is engageable. The piezoelectric actuator is disposed at a position close to the worm wheel,
The motor unit for a power window according to any one of claims 1 to 5, wherein the worm wheel functions as the brake ring, and an engagement portion of the piezoelectric actuator is engageable. . The energization switching means is a bridge circuit interposed between the motor and the piezoelectric actuator, and the piezoelectric actuator is moved in the same direction during forward or reverse energization of the motor for raising and lowering a power window. The power window motor unit according to any one of claims 1 to 8, wherein the motor unit is configured to be energized.

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