JP7222475B2 - motor actuator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a motor actuator for operating an airflow route switching door in a vehicle air conditioner.

As a motor actuator of this type, for example, Patent Document 1 discloses a motor having a power supply terminal as a drive source, a connector-side terminal arranged in an insertion port of an external connector for supplying external power to the motor, and a connector-side terminal. An actuator device is described that includes a pair of power supply terminals that are connected to the terminals and contact the power supply terminals of the motor in a state where elastic force is applied. As a result, external electric power can be supplied to the power supply terminal of the motor, and when the motor operates, the blowing path switching door connected to the actuator device operates.

JP 2012-90510 A

However, in the actuator device described in Patent Document 1, since the power supply terminal is in contact with the power supply terminal of the motor in a state in which an elastic force is applied, vibrations of the motor itself or the vehicle may cause the power supply terminal to contact the motor. Poor contact is likely to occur at the contact portion of the power supply terminal, resulting in reduced contact reliability and chattering noise, which may pose a problem especially in electric vehicles, where quietness is required.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor actuator in which chattering noise is eliminated and contact reliability is enhanced.

The motor actuator of the present invention is
a motor case, a bracket attached to the motor case, a rotating shaft supported by the motor case and the bracket, a commutator fixed to the rotating shaft, a brush in contact with the commutator, and the bracket a pair of power supply terminals fixed to and supplying power to the commutator;
a connector-side terminal having a pair of power feeding terminals;
a housing comprising a lower case and an upper case for fixing the motor and the connector-side terminal inside;
the power supply terminal is pulled out from the connector-side terminal in a first direction perpendicular to the assembly direction of the lower case and the upper case and the axial direction of the motor;
The power supply terminal is pulled out in the first direction from the radially outer side of the bracket,
the pair of power supply terminals and the pair of power supply terminals are electrically connected at different positions in the axial direction,
One end of the brush is fixed inside the bracket and is in contact with the commutator, and the other end is the power supply terminal outside the bracket in the radial direction, and is composed of the same continuous member,
Either the lower case or the upper case is formed with a fitting portion in which the power supply terminal and the power supply terminal are fitted,
The power feeding terminal and the power feeding terminal are fitted into the fitting portion and electrically connected to each other.

Since the motor actuator of the present invention has a structure in which the power supply terminal and the power supply terminal are fitted in the fitting portion, contact failure is less likely to occur due to vibrations of the motor itself or the vehicle, etc., and contact reliability is improved, resulting in chattering noise. not occur.

1 is a finished product of a motor actuator 1 according to an embodiment of the present invention, where (a) is a plan view and (b) is a sectional view taken along line AA of (a). (a) is a plan view of the upper case 20 of FIG. 1(a) viewed from the inside, and (b) is a plan view of FIG. 1(a) with the upper case 20 removed. (a) is a plan view excluding the output shaft 32 and the reduction gear 31 in FIG. 2(b), and (b) is a cross-sectional view taken along the line BB in (a). (a) is an enlarged view of arrow C in FIG. 3(a), and (b) is an enlarged view of arrow D in FIG. 3(b). (a) is a plan view of the lower case 10 excluding the connector-side terminal 40 and the motor 50 in FIG. be.

In this specification, in FIG. 1(b), the direction in which the upper case 20 and the lower case 10 are assembled is referred to as the "assembly direction" (X direction). The direction is called the "first direction" (Y direction), and in FIG. 2B, the direction parallel to the rotation axis 53 perpendicular to the assembly direction and the first direction is the "axial direction" (Z direction). , and in FIG. 2(b), the radial direction about the rotating shaft 53 is simply called the "radial direction".

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be exemplified below based on the drawings.

A motor actuator 1 of the present invention is shown in FIGS. 1 to 5, and is used, for example, as a drive source for an airflow control valve of an air conditioner.

The motor actuator 1 has a lower case (one case) 10 , an upper case (the other case) 20 , a reduction gear 31 , an output shaft 32 , a connector-side terminal 40 and a motor 50 .

The lower case 10 has a substantially rectangular bottom plate 11 , side plates 12 erected from the periphery of the bottom plate 11 , and an open end formed by the side plates 12 .
The upper case 20 has a substantially quadrilateral upper plate 21 , side plates 22 provided downward from the periphery of the upper plate 21 , and an open end formed by the side plates 22 .

The open end of the upper case 20 is assembled into the open end of the lower case 10 to form a housing 2 having a predetermined internal space. Inside the housing 2, a motor 50, a reduction gear 31, an output shaft 32, a connector-side terminal 40, and the like are arranged.
The lower case 10 is formed with a recess 16 into which the motor 50 is inserted and fixed, and the upper case 20 is formed with a recess 26 into which the motor 50 is inserted and fixed.

In addition, the lower case 10 has one raised portion 13 integrally erected from the inside of the bottom plate 11 . The rising portion 13 is formed only on the lower case 10 and is not formed on the upper case 10 .
The rising portion 13 is erected from the bottom plate 11 in the assembly direction, and has an end portion 13a on the upper end surface.

The end portion 13a is formed parallel to the first direction and the axial direction.
As shown in FIG. 5A, the end portion 13a has a groove portion 13b formed continuously in the first direction. The groove portion 13b serves as a fitting portion into which a power supply terminal 42 and a power supply terminal 56b, which will be described later, are fitted.
As shown in FIG. 5B, the groove portion 13b has a U-shaped cross section 13ba and an inclined cross-sectional portion 13bb extending from the U-shaped cross section 13ba in the opening direction. The inner bottom portion of the U-shaped cross section 13ba is arranged above the bottom plate 11 in the assembling direction, and the inner bottom portion and the bottom plate 11 have different heights in the assembling direction.
As shown in FIG. 5A, two grooves 13b are arranged in parallel with a gap in the axial direction and formed in the same shape.

The power supply terminal 42 and the power supply terminal 56b are fitted in the U-shaped cross section 13ba.

One of the side plates 12, 22 of the housing 2 is formed with an insertion port 14, 24 for an external connector protruding from the side plate 12, 22. As shown in FIG. Connectors (not shown) from an external device are inserted into the insertion openings 14 and 24 . When the connector of the external device is inserted into the receptacles 14 and 24, the external device is electrically connected to connector pins 43 provided in the receptacles 14 and 24, which will be described later.

Also, the insertion openings 14 and 24 are formed in the side plates 12 and 22 of the motor 50 directly facing a bracket 52 which will be described later. The side plates 12, 22 are formed perpendicular to the axial direction. Also, the sockets 14 and 24 and the motor 50 are arranged without overlapping in the axial direction of the motor. Also, the insertion direction of the insertion port is parallel to the axial direction of the motor.

Two reduction gears 31 are provided and connected to a worm gear 58 which will be described later.
The output shaft 32 is made of hard resin and has a flange-shaped output gear having a groove on its outer periphery. Also, the output shaft 32 is supported by shaft holes formed in the lower case 10 and the upper case 20 .
A pattern board 33 for detecting the rotational position of the output shaft 32 is fixed to one surface of the output shaft 32 , and the pattern board 33 rotates together with the rotation of the output shaft 32 .

The connector-side terminal 40 includes a pattern brush 41 that contacts the pattern board 33, a power supply terminal 42 connected to the power supply terminal 56b, a connector pin 43 for connection with an external device, and an insulating resin that holds them. and a holding portion 44 .
The connector-side terminal 40 is arranged near the left side plate of the lower case 10 in FIG. 3(a).
The connector-side terminal 40 is fixed by heat caulking by inserting a protrusion provided on the lower case 10 into a hole of an attachment portion provided integrally with the holding portion 44 .

The pattern brush 41 is in sliding contact with the pattern board 33 , so that a voltage value corresponding to the position of the output shaft 32 is detected, and the rotational position of the output shaft 32 is known.

The two power supply terminals 42 supply power from an external device to the power supply terminals 56b of the motor.
The two power supply terminals 42 are made of a conductive material and have a rectangular cross section.
The two power supply terminals 42 have one power supply terminal and the other power supply terminal, and are pulled out from the holding portion 44 in the first direction without contacting the lower case 10 and the upper case 20 . ing. These two power supply terminals 42 are arranged at different positions on the upper and lower sides in the axial direction so that they do not overlap when viewed from the assembly direction, and are arranged at the same height when viewed from the axial direction. and are pulled out from the holding portion 44 in the first direction with the same length.

A connector pin 43 is fixed to the receptacle 14, 24 and can be connected to a connector of an external device.

The motor 50 has a motor case 51, a bracket 52, a stator, a rotor, and motor brushes 56, and is inserted into and fixed to the recesses 16 and 26 of the lower case 10 and the upper case 20. there is The motor 50 is arranged near the side plate of the lower case 10 on the right side of the drawing in FIG. 3(a).

The motor case 51 is made of a metal material and consists of a cylindrical portion and an upper plate. A radial bearing is press-fitted into the central portion of the upper plate.
The bracket 52 is fitted in the opening of the motor case 51 and is integrally molded with an insulating material such as resin. A circular recess is formed in the central portion of the bracket 52, and the bottom surface of the recess serves as a thrust bearing. A radial bearing is press-fitted into the recess. The outer diameter of the bracket 52 is substantially the same as the inner diameter of the cylindrical portion of the motor case 51 .

The stator is fixed to the inner peripheral surface of the cylindrical portion of the motor case 51, and is composed of a cylindrical permanent magnet magnetized alternately with N poles and S poles along the circumferential direction.
The rotor consists of a rotary shaft 53, an armature core fixed to the rotary shaft 53 and formed by laminating a plurality of thin steel plates, a copper wire wound around the armature core in a coil shape, and fixed to the rotary shaft 53. and a commutator 54 electrically connected to the copper wires.
A rotating shaft 53 is inserted through the radial bearing and rotatably supported. One end of the rotary shaft 53 protrudes from the motor case 51 to which a worm gear 58 is fixed, and the other end is supported by a thrust bearing.

The side plates 12 and 22 are arranged close to the lower end of the bracket 52 .

A pair of motor brushes 56 are provided on the bracket 52 so as to be in sliding contact with the commutator 54 to allow current to flow.
The motor brush 56 is made of an electrically conductive elastic material such as copper or a copper alloy, and is formed in a substantially thin plate shape having a flat surface 56ba and side surfaces 56bb as shown in FIG. 3(a). The flat surface 56ba is wider than the side surface 56bb, and the side surface 56bb is narrower than the flat surface 56ba.

As shown in FIG. 3B, the two motor brushes 56 are arranged inside the bracket 52 symmetrically about the rotating shaft 53 .
One end 56a of the motor brush is fixed to the inside of the bracket 52 while being in contact with the commutator 54, and the other end 56b of the motor brush is a power feeder drawn out radially outward (in the first direction) from the bracket 52. It is a terminal. Since there are two motor brushes 56, the power supply terminal 56b has one power supply terminal and the other power supply terminal, and is pulled out without contacting the lower case 10 and the upper case 20, respectively.
One end 56a of the motor brush and the power supply terminal 56b, which is the other end of the motor brush, are made of the same continuous member.
The power supply terminal 56b is a so-called lateral protrusion that protrudes in one radial direction of the motor.

A motor brush 56 is inserted into and fixed to the bracket 52 . Specifically, the motor brush 56 is inserted and fixed inside the bracket 52 in the axial direction from the side surface 56bb. Therefore, as shown in FIG. 4(a), when viewed from the assembly direction, the power supply terminal 56b has a wide flat surface 56ba. However, since the power supply terminal 56b is fitted into the groove 13b of the raised portion in this state from the assembly direction, it is necessary to design the groove of the raised portion to be wide. Therefore, the power supply terminal 56b of this example is twisted at a predetermined angle (90° in this example) halfway so that the narrow side surface 56bb can be seen when viewed from the assembly direction. By forming in this way, the groove portion 13b of the rising portion can be designed to be narrow.

Also, the ends 56a of the two motor brushes are fixed at the same position in the axial direction so as to overlap each other when viewed from the assembly direction. If the overall shape of the motor brush is a substantially thin flat plate, if the two power supply terminals 56b are drawn out from the bracket 52 in the radial direction, the two power supply terminals 56b will overlap when viewed from the assembly direction. . Then, when viewed from the assembling direction, the two superimposed power supply terminals 56b and the two power supply terminals 42 whose positions are shifted upward and downward in the axial direction are difficult to fit into the groove 13b of the upright portion, and are electrically Difficult to connect.

Therefore, the two power supply terminals 56b are deformed upward and downward in the axial direction when viewed from the assembly direction (see FIG. 4A). Therefore, the two power supply terminals 56b and the two power supply terminals 42 can be easily fitted into the grooves 13b of the upright portion and electrically connected. That is, one power supply terminal and one power supply terminal can be electrically connected by being fitted into one groove of the rising part, and the other power supply terminal and the other power supply terminal can be connected to the other power supply terminal of the rising part. It can be electrically connected by being fitted into the groove.

The two power supply terminals 56b are drawn out from the bracket 52 radially outward (in the first direction). If the overall shape of the motor brush is a substantially thin flat plate, the two power supply terminals 56b are arranged at different heights in the assembly direction when viewed from the axial direction. Then, when viewed from the axial direction, the two power supply terminals 56b arranged at different heights and the two power supply terminals 42 arranged at the same height are difficult to fit into the grooves 13b of the rising portion, and are electrically connected. hard to do.

Therefore, the two power supply terminals 56b are deformed so that they have the same height when viewed from the axial direction (see FIG. 4B). Therefore, the power supply terminal 56b of this example is twisted at a predetermined angle (90° in this example) halfway so that a wide flat surface 56ba can be seen when viewed from the axial direction, and the height is the same in the assembly direction. placed in the Therefore, the two power supply terminals 56b and the two power supply terminals 42 can be easily electrically connected. That is, one power supply terminal and one power supply terminal can be electrically connected in one groove, and the other power supply terminal and the other power supply terminal can be electrically connected in the other groove.

Also, the two power supply terminals 56b are made of corrugated plates in the fitting portion of the groove.
As shown in FIG. 4(a), the minimum gap H1 in the fitting portion of the U-shaped cross section 13ba is the maximum thickness H2 of the power feeding terminal 42 and the power feeding terminal 56b having the corrugated plate before elastic deformation. slightly smaller than Specifically, the minimum gap H1 is the axial length of the groove, and the maximum thickness H2 is the axial length of the power supply terminal 42 and the power supply terminal 56b.

Then, when the power supply terminal 42 and the power supply terminal 56b are fitted into the groove 13b, the power supply terminal 56b is pressed against the power supply terminal 42 while being slightly elastically deformed at the fitting part, thereby being electrically connected.

With the above configuration, the rotation of the motor can be transmitted to, for example, the rotating shaft of the airflow control valve of the air conditioner via the worm gear 58, the reduction gear 31, and the output shaft 32.

The motor actuator 1 of this example has a motor 50 , connector-side terminals 40 and a housing 2 .
The motor 50 includes a motor case 51, a bracket 52 attached to the motor case 51, a rotating shaft 53 supported by the motor case 51 and the bracket 52, a commutator 54 fixed to the rotating shaft 53, and the bracket 52. and a power supply terminal 56b that is fixed to and supplies power to the commutator 54.
The connector-side terminal 40 has a power supply terminal 42 .
The housing 2 consists of a lower case 10 and an upper case 20 which fix the motor 50 and the connector-side terminal 40 inside.
The lower case 10 is integrally formed with a fitting portion in which the power feeding terminal 42 and the power feeding terminal 56b are fitted.
The power supply terminal 42 and the power supply terminal 56b are fitted into the fitting portion and electrically connected.

Therefore, since the motor actuator of this example has a structure in which the power supply terminal and the power supply terminal are fitted in the fitting portion, contact failure is less likely to occur due to vibrations of the motor itself or the vehicle, etc., and contact reliability is improved. No chattering noise.
In addition, in the motor actuator of this example, the power supply terminal and the power supply terminal are electrically connected by being fitted into the fitting portion, eliminating the need for soldering connection. .

Further, the lower case 10 has an upright portion 13 inside.
The rising portion 13 is formed with an end portion 13a.
A groove portion 13b is formed in the end portion 13a.
The groove portion 13b is the fitting portion described above.
The power supply terminal 42 and the power supply terminal 56b are fitted into the groove 13b and electrically connected.

Therefore, in the motor actuator of this example, the power supply terminals and the power supply terminals are fitted into the grooves of the rising portion, so contact failure is less likely to occur due to vibrations of the motor itself or the vehicle, etc., and contact reliability is improved. and eliminates chattering noise.
In addition, the power supply terminal and the power supply terminal are fitted into the groove of the upright portion and electrically connected, eliminating the need for soldering connection.

Also, the power supply terminal 42 is drawn out from the connector-side terminal 40 in a first direction perpendicular to the assembly direction of the lower case 10 and the upper case 20 .
The power supply terminal 56b is drawn out from the motor in the first direction.
The groove portion 13b is formed continuously in the first direction.
Therefore, in the motor actuator of this example, since the power supply terminal and the power supply terminal are arranged in the first direction, the connector side terminal and the motor can be electrically connected at the shortest distance, and the space for routing the terminals can be reduced. can be made smaller.

Also, the first direction is one radial direction of the motor.
The motor 50 has motor brushes 56 .
One end 56a of the motor brush is fixed inside the bracket 52 while being in contact with the commutator 54, and the other end of the motor brush is a power supply terminal 56b.
One end of the motor brush and the other end of the motor brush are formed of the same seamless member.
Therefore, in the motor actuator of this example, the motor serves as a lateral power supply terminal. Then, when the motor brush is extended in the radial direction of the motor, the extended portion becomes the power supply terminal as it is, and the terminal can be easily routed.

Further, the power supply terminal 56b is a corrugated plate at the fitting portion of the groove.
The minimum gap H1 in the fitting portion is slightly smaller than the maximum thickness H2 of the overlapping power supply terminal and power supply terminal.
Therefore, in the motor actuator of this example, the power supply terminal and the power supply terminal are elastically pressed against the groove, so that it is easy to ensure contact stability.

Further, the groove portion 13a has a cross-sectional inclined portion 13bb that widens in the opening direction of the groove portion 13a. Therefore, in the motor actuator of this example, the power supply terminal and the power supply terminal can be easily fitted into the groove, and the assembling workability can be improved.

Further, the power supply terminal 42 has one power supply terminal and the other power supply terminal.
The power supply terminal 56a has one power supply terminal and the other power supply terminal.
Two grooves 13b are formed at the end.
One power supply terminal and one power supply terminal are fitted into one groove and electrically connected.
The other power supply terminal and the other power supply terminal are fitted into the other groove and electrically connected.
Therefore, the power supply terminal and the power supply terminal can be electrically connected.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above, and various modifications other than those described above can be made without departing from the gist of the present invention.

In the description of the above embodiment, the raised portion 13 having the groove portion 13b was formed in the lower case 10, but the present invention is not limited to this.
For example, the raised portion having the groove may be formed in the upper case instead of the lower case.

Further, in the description of the above embodiment, the fitting portion is a groove formed at the end of the rising portion, and the two power supply terminals 42 extend from the holding portion 44 to the lower case 10 in the first direction. The power supply terminal 56b is drawn out from the motor in the radial direction without contacting the lower case 10 and the upper case 20, but the present invention does not make contact with the upper case 20. is not limited to
For example, the fitting portion may be a groove formed inside the bottom plate 11 of the lower case instead of the end of the rising portion. In this case, the power supply terminal and the power supply terminal are deformed so that they can be fitted into the fitting portion, and are fitted into the fitting portion formed inside the bottom plate 11 while contacting the bottom plate 11 of the lower case. properly connected.

Further, in the description of the above embodiment, the corrugated plate is formed on the power supply terminal in the fitting portion, but the present invention is not limited to this.
For example, the corrugated plate may be formed on the power supply terminal instead of on the power supply terminal. That is, in the fitting portion, the feeding terminal may be a corrugated plate and the feeding terminal may be a flat plate.
Further, for example, in the fitting portion of the groove, both the power supply terminal and the power supply terminal may be flat plates. In this case, the minimum gap H1 in the fitting portion is substantially the same as the maximum thickness H2 of the power supply terminal and the power supply terminal. and

In addition, in the description of the above embodiment, the groove portion 13b has the U-shaped cross section 13ba and the inclined cross-sectional portion 13bb extending from the U-shaped cross section 13ba in the opening direction, but the present invention is not limited thereto.
For example, the groove may have only a U-shaped cross section, and the minimum gap H1 in this groove may be slightly smaller than the maximum thickness H2 of the overlapping power supply terminal and power supply terminal. In this example, although it is slightly more difficult to fit into the groove than in the above-described embodiment, the electrical connection between the power supply terminal and the power supply terminal can be ensured, and contact failure is less likely to occur, and contact reliability is improved. No chattering noise.

In addition, in the description of the above-described embodiment, the power supply terminal 56b protrudes laterally from the motor case in the radial direction of the motor, but the present invention is not limited to this.
For example, the power supply terminals may not be laterally protruding, but may be longitudinally protruding from the bracket in the axial direction of the motor. The vertically protruding power supply terminal has a shape that extends around the outside of the bracket, and is fitted into the aforementioned fitting portion.

In addition, in the description of the above embodiment, the fitting portion is a groove portion, but the present invention is not limited to this.
For example, the fitting portion may have a shape in which a plurality of projections formed on the upright portion are used, and the power supply terminal 42 and the power supply terminal 56b are fitted between the projections so that they can be electrically connected.
Further, for example, the fitting portion may be shaped so that the power supply terminal 42 and the power supply terminal 56b are fitted together and electrically connected using a cut-and-raised piece with a hook formed inside the case.

Further, in the above description, the lower case 10 is integrally formed with a fitting portion in which the power feeding terminal 42 and the power feeding terminal 56b are fitted, but may be formed separately.

REFERENCE SIGNS LIST 1 motor actuator 2 housing 10 lower case 11 bottom plate of lower case 12 side plate of lower case 13 rising portion 13a end of rising portion 13b groove (fitting portion) at the end of rising portion
13ba Groove section U-shaped section 13bb Groove section inclined section 14 Lower case insertion port 16 Recess 20 Upper case 21 Upper case upper plate 22 Upper case side plate 24 Upper case insertion port 26 Recess 31 Reduction gear 32 Output shaft 33 Pattern board 40 Connector side terminal 41 Pattern brush 42 Power supply terminal 43 Connector pin 44 Holding part 50 Motor 51 Motor case 52 Bracket 53 Rotating shaft 54 Commutator 56 Motor brush 56a One end of motor brush 56b The other end of motor brush (Power supply terminal)
56ba Flat surface of the other end of the motor brush 56bb Side surface of the other end of the motor brush 58 Worm gear

Claims (7)

a motor case, a bracket attached to the motor case, a rotating shaft supported by the motor case and the bracket, a commutator fixed to the rotating shaft, a brush in contact with the commutator, and the bracket a pair of power supply terminals fixed to and supplying power to the commutator;
a connector-side terminal having a pair of power feeding terminals;
a housing comprising a lower case and an upper case for fixing the motor and the connector-side terminal inside;
the power supply terminal is pulled out from the connector-side terminal in a first direction perpendicular to the assembly direction of the lower case and the upper case and the axial direction of the motor;
The power supply terminal is pulled out in the first direction from the radially outer side of the bracket,
the pair of power supply terminals and the pair of power supply terminals are electrically connected at different positions in the axial direction,
One end of the brush is fixed inside the bracket and is in contact with the commutator, and the other end is the power supply terminal outside the bracket in the radial direction, and is composed of the same continuous member,
Either the lower case or the upper case is formed with a fitting portion in which the power supply terminal and the power supply terminal are fitted,
A motor actuator, wherein the power supply terminal and the power supply terminal are fitted into the fitting portion and electrically connected. Either one of the lower case and the upper case has an inner raised portion,
An edge is formed on the rising portion,
A groove is formed in the end,
2. The motor actuator according to claim 1, wherein the groove portion is the fitting portion. 3. A motor actuator according to claim 2, wherein said groove is formed continuously in said first direction. Either one of the power supply terminal and the power supply terminal is a corrugated plate in the fitting portion,
2. The motor actuator according to claim 1, wherein the minimum gap in said fitting portion is slightly smaller than the maximum thickness of said power supply terminal and said power supply terminal. The power supply terminal has one power supply terminal and the other power supply terminal,
The power supply terminal has one power supply terminal and the other power supply terminal,
Two grooves are formed at the end,
the one power supply terminal and the one power supply terminal are fitted into one of the grooves and electrically connected,
3. A motor actuator according to claim 2, wherein said other power feeding terminal and said other power feeding terminal are fitted into said other groove and electrically connected. 3. The motor actuator according to claim 2, wherein the groove has a U-shaped cross section. 3. A motor actuator according to claim 2, wherein said groove has a cross-sectional inclined portion that widens in an opening direction of said groove.

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