JP5583995B2 - Motor actuator - Google Patents

Description

  The present invention relates to a motor actuator provided with a rotation angle detector.

For example, a motor actuator that is driven by an electric motor is known as a drive source for an airflow control valve of an air conditioner used in a vehicle such as an automobile.
Such a motor actuator includes an upper case 101 and a lower case 102 shown in FIGS. 12 (a) and 12 (b), and an output shaft 104 to which the rotation of the motor 103 is transmitted is held between the upper and lower cases. ing. A potentiometer 105 of a rotation angle detector that detects the angle of the output shaft 104 by inserting the output shaft 104 is attached to the lower case 102.
The potentiometer 105 includes a rotating body 107 having an insertion hole into which one end of the output shaft 104 is mounted and a brush 106 provided thereon, and a resistor substrate that supports the rotating body 107 and is disposed to face the brush 106. A non-rotating body 108 is provided.

  It is impossible for the potentiometer 105 and the output shaft 104 to have the same insertion hole of the potentiometer 105 and the output shaft 104, and there is usually a dimensional difference. At this time, for example, when the insertion hole is made slightly larger than the output shaft 104, the clearance generated thereby becomes a dead zone, and the accuracy of angle detection of the output shaft decreases. In addition, if the insertion hole is slightly smaller than the output shaft 104 and press-fitted, the clearance can be eliminated and the detection accuracy can be increased, but the press-fitting keeps applying a load to the potentiometer, resulting in cracks and deformation. This will cause the durability to decrease.

  In order to solve such a problem, for example, in Patent Document 1, as shown in FIGS. 13A and 13B, a D-cut shape that constitutes an insertion hole (mounting hole) 109 of the potentiometer 105. A hemispherical projection 110 and a protruding portion 111 that are plastically deformed are formed in the hole. According to such a structure, when the output shaft is inserted into the insertion hole, the hemispherical protrusion and the protruding portion are plastically deformed, and the output shaft is fixed to the insertion hole, so that a large load is applied to the potentiometer. It is said that the detection accuracy of the output shaft can be improved by eliminating the clearance between the rotating body and the output shaft.

JP 2002-267439 A

However, if there is a fitting error in the upper and lower cases of the motor actuator, the output shaft 104 is inclined as shown in FIG. 12C, but the non-rotating body 108 of the potentiometer cannot be moved because it is attached to the lower case 102. The rotating body 107 fixed to the output shaft 104 is inclined to move.
Therefore, an excessive lateral pressure is applied between the rotating body and the non-rotating body, causing abnormal wear, increasing the load of the brush, promoting the wear of the brush, and reducing the durability.
If the clearance between the output shaft and the insertion hole of the rotating body is increased, the rotating body can be prevented from tilting even if the output shaft is tilted, but the angle detection accuracy is lowered. Further, if the fitting accuracy is increased to the limit so as to eliminate the fitting error between the upper and lower cases, the processing cost increases and the cost increases.

  Therefore, an object of the present invention is to provide a motor actuator that can prevent a decrease in durability of a potentiometer without reducing the angle detection accuracy of an output shaft even if there is a fitting error in the upper and lower cases.

The present invention has been made in order to achieve the above Symbol purpose of,
An upper and lower case constituting a housing, a motor disposed in the housing, a reduction gear coupled to a rotating shaft of the motor, an upper end side is supported by the upper case, and a lower end side is supported by the lower case, A motor actuator comprising an output shaft connected to a reduction gear and rotating, and a rotation angle detector for detecting a rotation angle of the output shaft,
The upper and lower cases have an upright part on the inside,
The output shaft has an insertion portion with a non-circular cross section,
The rotation angle detector includes a rotating body having a mounting hole through which the insertion portion of the output shaft is inserted, a non-rotating body that pivotally supports the rotating body, and a rotation angle of the output shaft by rotation of the rotating body. A detection means for detecting,
The non-rotating body is sandwiched between the upper and lower cases;
On the inner peripheral surface of the mounting hole or the insertion portion, a rib is provided for restricting the insertion portion so as to contact only a part of the rotating body in the thickness direction.
The rib is provided on the mounting hole of the rotating body so as to protrude in a part of the thickness direction of the rotating body over the entire circumference.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of durability can be prevented by suppressing the inclination of the rotary body of the rotation angle detector by the inclination of an output shaft.

The disassembled perspective view of the motor actuator in the 1st Embodiment of this invention is shown. 2A is a top view of the finished product excluding the upper case of the motor actuator of FIG. 1, and FIG. 2B is a cutting line A of FIG. 2A when there is no fitting error between the upper and lower cases. FIG. 2C is a cross-sectional view taken along line AA in FIG. 2A when the upper and lower cases have a fitting error. 3A is a cross-sectional view showing the main part of the rotation angle detector of FIG. 1, and FIG. 3B is a top view of FIG. 4A is a cross-sectional view when the output shaft is inserted into the mounting hole of the rotation angle detector of FIG. 3, and FIG. 4B is a rotation of the rib of the mounting hole of the rotating body of FIG. 3. It is sectional drawing when it is formed in the upper end of the thickness direction of a body and an output shaft is inclined and inserted. 5A is a cross-sectional view in the case of a broad shape in which the base end portion of the rib of the mounting hole in FIG. 3 reaches the upper and lower ends of the mounting hole, and FIG. 5B is a top view of FIG. Indicates. It is sectional drawing which shows the case where the insertion part of an output shaft is inclined and inserted in the mounting hole of the rotary body of FIG. FIG. 7A is a cross-sectional view showing the main part of the rotation angle detector in the second embodiment, and FIG. 7B is a top view of FIG. 7A. FIG. 8 is a cross-sectional view when the insertion portion of the output shaft is inclined and fitted into the mounting hole of the rotating body of FIG. 7. FIG. 9A is a cross-sectional view showing the main part of the rotation angle detector according to the third embodiment, and FIG. 9B is a top view of FIG. 9A. It is sectional drawing which shows the principal part of the motor actuator in 4th Embodiment. It is sectional drawing which shows the modification of the rotation angle detector of the motor actuator in 1st Embodiment. FIG. 12A is a reference diagram for explaining the problem to be solved by the present invention, and is a top view of the finished product excluding the upper case of the motor actuator, and FIG. FIG. 12C is a cross-sectional view taken along the cutting line FF in FIG. 12A when there is no fitting error, and FIG. 12C shows that the upper and lower cases have a fitting error and the output shaft is inclined from a predetermined position. It is sectional drawing of the cutting line FF of Fig.12 (a) in the case. FIG. 13A is a perspective view of a conventional rotation angle detector, and FIG. 13B is a perspective view of another conventional rotation angle detector.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIGS. 1 and 2, a motor actuator 1 according to the present invention is used as a drive source of an air flow regulating valve of an air conditioning apparatus used in a vehicle such as an automobile, and includes an upper and lower case constituting a housing, A motor 31 disposed on the motor 31, a reduction gear connected to the rotation shaft 31 </ b> A of the motor 31, an output shaft 41 connected to the reduction gear and rotating, and a rotation angle detector 51 that detects the rotation angle of the output shaft 41. It is what it has.

  The housing is formed in a box shape in which the opening ends of the upper case 11 and the lower case 12 are fitted to each other and have a predetermined internal space.

The motor 31 is disposed in the housing. A worm gear 32 is fixed to the rotating shaft 31 </ b> A of the motor 31, and a reduction gear is connected to the worm gear 32.
The reduction gear of this example has a first intermediate gear 33 and a second intermediate gear 34, the first intermediate gear 33 is connected to the worm gear 32, and the second intermediate gear 34 is connected to the first intermediate gear 33. The

  The output shaft 41 is formed of a hard resin and has a flange-shaped output gear 42 having a groove on the outer periphery. The output gear 42 is connected to the second intermediate gear 34.

The upper end 43 of the output shaft is formed in a cylindrical shape and is rotatably supported by protruding from a guide hole 11A provided in the bottom plate of the upper case 11, and the air flow control valve of the air conditioner (not shown) is provided on the cylindrical inner periphery. The rotating shaft is locked.
The lower end 44 of the output shaft is coaxial with the upper end 43 of the output shaft, and is inserted into a bearing 12A provided integrally with the inner bottom surface of the lower case 12, and is rotatably supported.
An insertion portion 45 having a non-circular cross section is provided on the lower end 44 side of the output shaft. In this example, the cross section of the insertion part 45 has a D shape.

  With the configuration described above, the rotation of the motor can be transmitted to the rotation shaft of the airflow adjustment valve of the air conditioner via the worm gear, the reduction gear, and the output shaft.

The rotation angle detector 51 of this example is composed of a potentiometer, and includes a hard resin rotating body 53 having a mounting hole 52 through which the insertion portion 45 of the output shaft 41 is inserted, and a non-rotating body that pivotally supports the rotating body 53. 54.
The rotating body 53 is provided with a brush 55. On the other hand, the non-rotating body 54 is provided with a resistor substrate (not shown) that is in sliding contact with the brush 55.
The brush 55 and the resistor substrate function as detection means for detecting the rotation angle of the output shaft 41 by the rotation of the rotating body 53, and can detect a voltage signal corresponding to the rotation angle of the output shaft 41.

In the motor actuator 1 of this example, the upper and lower cases each have three rising portions made of rising ribs of the same height inside the case, and the tip of the rising portion 13A of the lower case 12 is connected to the bottom surface of the case. It is formed with a parallel flat surface, and the tip of the upright portion 13B of the upper case 11 is formed to be sharp.
On the other hand, the non-rotating body 54 of the potentiometer is provided with holding portions 56A, 56B, and 56C at three portions corresponding to the upright portions 13A and 13B of the upper and lower cases. The portions 56B and 56C are sandwiched between the upper and lower cases 13A and 13B. The holding portions 56A and 56B are provided at both left and right ends of the non-rotating body 54, and the holding portion 56C is provided at the tip of an arm portion provided on the outer periphery of the non-rotating body 54, and these holding portions 56A, 56B and 56C. Are arranged apart from each other in the outer peripheral portion of the non-rotating body 54.

  Further, in the motor actuator of this example, as shown in FIG. 3, a protruding rib 57 is provided on the inner peripheral surface of the mounting hole 52 of the rotating body 53. The rib 57 is for restricting the insertion portion 45 of the output shaft 41 to contact only a part of the rotating body 53 in the thickness direction. In this example, the insertion portion 45 of the output shaft 41 is only the rib 57. It is made into the shape which continued to a part of thickness direction of the rotary body 53 over the perimeter so that it may contact.

  When assembling the motor actuator of this example, the motor 31 and the reduction gear are arranged at predetermined positions of the lower case 12, the output shaft 41 is attached to the rotation angle detector 51, and the lower end 44 of the output shaft is connected to the lower case 12. The upper case 11 is fitted to the lower case 12 while being inserted into the bearing 12 </ b> A and the rotation angle detector 51 is placed on the rising portion 13 </ b> A of the lower case 12. When the rotation angle detector 51 is placed on the upright portion 13A of the lower case 12, the holding portions 56A, 56B, and 56C of the non-rotating body 54 are placed on the upright portion 13A. Since the holding portions 56A, 56B, and 56C are disposed apart from each other on the outer peripheral portion of the non-rotating body 54, the non-rotating body 54 is stably placed on the rising portion 13A of the lower case 12.

  When there is no fitting error in the upper and lower cases, as shown in FIG. 2 (b), the output shaft 41 does not tilt, and the upper case 11 remains in the original state where the members are arranged in the lower case 12. The lower case 12 is fitted.

  When there is a fitting error in the upper and lower cases, the output shaft is inclined as shown in FIG. At this time, when the rotation angle detector is fixed in advance to the lower case as in the prior art, there is no sufficiently large clearance between the insertion portion of the output shaft and the inner peripheral surface of the mounting hole of the rotating body. Excessive side pressure is applied between the output shaft and the rotating body, and also between the rotating body and the non-rotating body, and abnormal rotation is likely to occur in these members due to the rotation of the output shaft. Further, the rotating body is also tilted by the side pressure due to the tilt of the output shaft, the load of the brush is increased, the wear of the brush is promoted, and the durability is lowered.

  On the other hand, in the motor actuator of this example, the rotation angle detector 51 is not fixed to the lower case 12, and the upper case 11 is assembled in a state where the rotation angle detector 51 is placed on the rising portion 13 </ b> A of the lower case 12. For this reason, when the upper and lower cases are fitted, the rotation angle detector 51 can move in the case in the lateral direction by the amount by which the output shaft 41 is inclined.

  In addition, in the motor actuator of this example, the contact portion between the insertion portion 45 of the output shaft 41 and the rotating body 53 is limited to a rib formed only in a part in the thickness direction of the rotating body 53. For this reason, even if the clearance between the insertion portion 45 of the output shaft 41 and the rib of the rotating body 53 is relatively narrow, the output shaft 41 can be inclined relatively large within the mounting hole. That is, a conventional method in which a small protrusion is formed on a D-shaped linear portion as shown in FIG. 13A, or a stripe-like protrusion extending in the entire thickness direction of the rotating body 53 as shown in FIG. 13B. In this case, if the clearance is narrow, the output shaft 41 can hardly be tilted. However, by providing the rib as in this example, the output shaft 41 can be largely tilted even with the same clearance.

For these reasons, in the motor actuator of this example, even if the clearance between the insertion portion 45 of the output shaft 41 and the rib 57 of the rotating body 53 is narrow, each member is caused by the inclination of the output shaft due to the fitting error of the upper and lower cases. The side pressure generated between them can be almost eliminated, and abnormal wear of each member can be prevented. Further, even if the output shaft 41 is tilted, the rotating body 53 of the potentiometer is hardly tilted and the brush load does not increase.
Therefore, in the motor actuator of this example, even if there is a fitting error in the upper and lower cases, the tilt of the rotary body of the potentiometer can be suppressed without reducing the angle detection accuracy of the output shaft, and the durability can be prevented from being lowered.

  In the present invention, the height H1 of the rib 57 shown in FIG. 3 is appropriately designed according to the assumed maximum fitting error of the upper and lower cases, the thickness W of the rotating body 53, and the like. More specifically, even when the maximum inclination of the output shaft 41 occurs due to the maximum fitting error between the upper and lower cases, the insertion portion 45 of the output shaft 41 does not contact the upper and lower end edges of the inner peripheral surface of the mounting hole, and the rib The height H1 of the rib is designed so as to contact only 57.

  The rib 57 may be formed at any position in the thickness direction of the rotating body 53, but it is particularly preferable that the rib 57 be formed at an intermediate portion in the thickness direction of the rotating body 53. For example, as shown in FIG. 4, when compared with ribs having the same shape, it is formed at the end of the rotating body 53 in the thickness direction (see FIG. 4A). Rather than doing this (see FIG. 4B), the tilt of the rotating body 53 can be allowed to be larger. That is, if the rib is formed at the intermediate portion in the thickness direction of the rotating body 53, the height of the rib can be reduced, and the degree of freedom in designing each member can be increased.

  Further, the width W1 of the rib tip shown in FIG. 3 is desirably as narrow as possible if there is no problem in strength. If the width W1 of the rib tip is too wide, the effect of the present invention cannot be obtained sufficiently. For this reason, the width W1 is preferably 1/2 or less of the thickness W of the rotating body 53, and particularly preferably 1/4 or less of the thickness W of the rotating body 53.

  The cross-sectional shape of the rib is not limited to the form as shown in FIG. 3, and for example, a broad shape in which the base end portion of the rib reaches the upper and lower edges of the mounting hole 52 as shown in FIG. In the case of the configuration as shown in FIG. 5, the rib inclination angle α is designed to be larger than the maximum inclination angle β generated in the output shaft due to the maximum fitting error of the upper and lower cases (see FIG. 6). Thereby, the insertion part 45 of the output shaft 41 does not contact | abut to the inclined surface 53A of a rib, and the side pressure produced between each member can be almost eliminated.

  The opening formed by the rib is preferably formed to have substantially the same cross-sectional shape as the insertion portion 45 of the output shaft 41. When the cross section of the insertion portion 45 is D-shaped as in this example, the shape of the opening formed by the rib is also D-shaped to minimize the clearance and maximize the detection accuracy of the output shaft 41. Can be increased to the limit.

  Thus, in this embodiment, even if the clearance between the insertion portion of the output shaft and the rib of the rotating body is narrow, the side pressure generated between the members due to the inclination of the output shaft due to the fitting error of the upper and lower cases is almost eliminated. In addition, even if the output shaft is tilted, the rotating body of the potentiometer is hardly tilted and the brush load does not increase. For this reason, it is possible to prevent a decrease in the durability of the rotation angle detector without reducing the angle detection accuracy of the output shaft.

(Second Embodiment)
Fig.7 (a) is sectional drawing which shows the principal part of the rotation angle detector concerning 2nd Embodiment, FIG.7 (b) shows the top view of Fig.7 (a).
FIG. 8 is a cross-sectional view when the insertion portion of the output shaft is inclined and fitted into the mounting hole of the rotating body of FIG.
7 and 8, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
The present embodiment is different from the first embodiment in that the tip of the protruding rib 60 is a hemispherical protrusion. In this embodiment, the inner diameter of the protruding rib 60 is slightly smaller than the outer diameter of the insertion portion 45 of the output shaft 41, and the insertion portion 45 of the output shaft 41 is lightly press-fitted into the protruding rib 60. Since the tip of the rib is a hemispherical projection, the rotating body of the potentiometer hardly tilts with the tilt of the output shaft. Therefore, it is possible to more effectively reduce the application of excessive lateral pressure to the periphery of the non-rotating body that supports the rotating body, and the brush load of the rotation angle detector does not increase, thereby preventing a decrease in durability.

(Third embodiment)
FIG. 9A is a cross-sectional view showing the main part of the rotation angle detector according to the third embodiment, and FIG. 9B is a top view of FIG. 9A.
In FIG. 9, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
In this embodiment, the difference from the first embodiment is that the mounting hole 52 of the rotating body 53 has a cross section formed in a D shape, and a left flat portion 71 divided by a line 75 that bisects the D shape symmetrically. At least one protruding rib 58 is provided on each of the right flat portion 72, the left bending portion 73, and the right bending portion 74, and the protruding rib 58 is formed in a part of the thickness direction of the rotating body 53 in the thickness direction. It is a point provided so that it may be located on the same plane orthogonal to. At least two adjacent ribs 58 may be provided continuously.

  Even in this embodiment, by suppressing the inclination of the rotating body of the rotation angle detector due to the inclination of the output shaft, it is possible to effectively reduce the application of excessive lateral pressure to the periphery of the non-rotating body that supports the rotating body. In addition, since a predetermined clearance can be secured between the brush and the resistor substrate and the brush load of the rotation angle detector does not increase, it is possible to prevent a decrease in durability.

(Fourth embodiment)
FIG. 10 is a cross-sectional view showing the main parts of the motor actuator according to the fourth embodiment.
In FIG. 10, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
The present embodiment is different from the first embodiment in that the insertion portion 45 of the output shaft 41 facing the inner periphery of the mounting hole 52 of the rotating body 53 protrudes partly in the axial direction of the output shaft 41 over the entire circumference. The point which is provided with the shape-like rib 59 is.
Even in this embodiment, the same effect as in the first embodiment can be obtained.

(Modification)
FIG. 11 illustrates a modification of the rotation angle detector of the motor actuator according to the first embodiment.
In this modification, the difference from the first embodiment described above is that the rotation angle detector is a potentiometer in the above description, but the rotation angle detector 81 of this modification has a predetermined conductive portion and insulating portion. A rotating body 82 provided with a plate portion (not shown) arranged at an interval and rotating integrally with the output shaft 41, and a non-rotating body 84 provided with a brush 83 facing the plate portion and supporting the rotating body 82, This is a point that becomes a pulse sensor including detection means for detecting the rotation angle of the output shaft 41 by the rotation of the rotating body 82.
This pulse sensor also has the same effect as described above.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention, for example, with respect to the upright portion, the protruding rib, and the mounting hole of the rotating body. Needless to say.

DESCRIPTION OF SYMBOLS 1 Motor actuator 11 Upper case 11A Guide hole 12 Lower case 12A Bearing 13A Upright part 13B Upright part 31 Motor 31A Rotating shaft 32 Worm gear 33 First intermediate gear 34 Second intermediate gear 41 Output shaft 42 Output gear 43 Upper end of output shaft 44 Output Lower end of shaft 45 Insertion part 51 Rotation angle detector 52 Mounting hole 53 Rotating body 53A Inclined surface 54 Non-rotating body 55 Brush 56A Holding part 56B Holding part 56C Holding part 57 Projecting rib 58 Projecting rib 59 Projecting rib 60 Projecting rib 71 Left flat part 72 Right flat part 73 Left curved part 74 Right curved part 75 Divided line 81 Rotating angle detector 82 Rotating body 83 Brush 84 Non-rotating body H1 Rib height W Rotating body Thickness W1 Rib tip width α Rib tilt angle β Maximum tilt angle generated by the output shaft

Claims (1)

An upper and lower case constituting a housing, a motor disposed in the housing, a reduction gear coupled to a rotating shaft of the motor, an upper end side is supported by the upper case, and a lower end side is supported by the lower case, A motor actuator comprising an output shaft connected to a reduction gear and rotating, and a rotation angle detector for detecting a rotation angle of the output shaft,
The upper and lower cases have an upright part on the inside,
The output shaft has an insertion portion with a non-circular cross section,
The rotation angle detector includes a rotating body having a mounting hole through which the insertion portion of the output shaft is inserted, a non-rotating body that pivotally supports the rotating body, and a rotation angle of the output shaft by rotation of the rotating body. A detection means for detecting,
The non-rotating body is sandwiched between the upper and lower cases;
On the inner peripheral surface of the mounting hole or the insertion portion, a rib is provided for restricting the insertion portion so as to contact only a part of the rotating body in the thickness direction.
The motor actuator according to claim 1, wherein the rib is provided in a projecting shape in a part of the rotating body in a thickness direction of the mounting body in the thickness direction of the rotating body.

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