JP3798683B2 - Rotation detector for small motor with worm reducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation detection device in a small motor with a worm reduction gear used for raising and lowering a window glass of an automobile, for example.
[0002]
[Prior art]
Conventionally, a small motor with a worm reduction gear has been used for raising and lowering the window glass of an automobile. The rotational power of the motor shaft moves up and down the window glass through the worm and the worm wheel, and further through the glass lifting mechanism coupled to the output shaft. In order to detect the position and speed of the window glass, a rotation detection device is integrated into a small motor with a worm reduction gear. Such a rotation detection device is composed of a magnetic pole attached to the rotating part and a Hall element attached to the stationary part, and the magnetic flux from the magnetic pole changes based on the relative movement of both corresponding to the motor rotation. Since this is detected by the Hall element and generated as a pulse signal, a wiring for supplying current to the Hall element and taking out the signal is required together with a space for mounting the rotation detecting device. Become.
[0003]
Conventionally, there is no sufficient space for mounting the rotation detection device on the motor portion side of such a small motor with a worm reduction gear, and therefore the rotation detection device has been mounted on the worm reduction gear side. Japanese Patent Application Laid-Open No. 6-217497 discloses such a technique, in which a magnetic plate having magnetic poles alternately magnetized on the circumference is attached to the worm wheel output shaft on the worm speed reducer side. Cost.
[0004]
[Problems to be solved by the invention]
When the rotation detection device is attached to the worm speed reducer side, there is a problem that a wiring configuration for supplying current to the Hall element and taking out a signal is required separately from the configuration for supplying power to the motor.
[0005]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such problems and secure a sufficient space on the motor side for mounting the rotation detecting device and mounting the rotation detecting device there.
[0006]
Accordingly, an object of the present invention is to provide a small motor with a worm speed reducer in which a motor power supply configuration and a wiring configuration for rotation detection are integrated to make the overall configuration compact.
[0007]
[Means for Solving the Problems]
The rotation detection device for a small motor with a worm speed reducer according to the present invention includes an end bell fitted to close an opening of a bottomed hollow cylindrical metal case to which a stator magnetic pole is attached, and a bottom portion and an end bell of the metal case. Provided is a small motor having a rotor formed by integrally assembling a rotor magnetic pole and a commutator on shafts rotatably supported by bearings provided respectively, and two brushes abutting on the commutator. . Then, the drive torque from the small motor is output through a worm reduction gear including a worm and a worm wheel press-fitted to the shaft of the small motor. The end bell is provided with an opening formed by a side wall extending in a direction perpendicular to the motor shaft axial direction. The end bell is inserted into the end bell opening in a direction perpendicular to the shaft axial direction. The brush assembly is configured to abut on the child and has a pair of first terminals for supplying power to the two brushes. On the shaft, a rotation detecting magnet is provided adjacent to or near the commutator. A Hall element is provided in the brush assembly that is in a stationary position relative to the rotation detection magnet and detects a magnetic flux that changes as the rotation detection magnet rotates and outputs a rotation detection signal. The brush assembly further includes a printed circuit board having wiring for supplying a current to the Hall element and taking out a signal therefrom, and a plurality of second wirings for connecting the wiring on the printed circuit board to the outside of the motor. And a terminal.
[0008]
In addition, the first terminal and the second terminal of the brush assembly are arranged adjacent to each other, and external connection is made possible by a single connector to these terminals.
[0009]
The worm speed reducer includes a second speed reduction gear portion that meshes with the first speed reduction gear portion including the worm wheel, and takes out torque from an output shaft coupled to the center of the second speed reduction gear portion. Constitute.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on examples. FIG. 1 is a diagram illustrating the appearance of a whole small motor with a speed reducer to which the present invention is applied, and FIG. 2 is a diagram of the same small motor as in FIG. It is a figure which shows a part in a cross section. As shown in the figure, the small motor with a speed reducer is composed of a motor part and a speed reducer part that are integrally coupled by screws or the like. The reduction gear unit has a two-stage reduction configuration including a first reduction gear unit 27 and a second reduction gear unit 28. First, the structure of this reduction gear part is demonstrated with reference to FIG.3 and FIG.4 further.
[0011]
FIG. 3 is a diagram showing, in partial cross section, a small motor with a reduction gear to which the present invention is applied, and FIG. 3 (A) is an overall configuration diagram showing in partial cross section when the motor shaft is viewed in the lateral direction. B) is a cross-sectional side view cut at the reduction gear section. FIG. 4 is an overall perspective view of the small motor with a speed reducer shown in FIG. 3, but some components are not shown for easy understanding of the operation.
[0012]
In these drawings, the motor portion is attached to the speed reducer portion via a screw, and the tip end portion of the motor shaft 1 is fixed by a bearing portion 8 provided in the speed reducer portion housing 26. The worm 7 includes a worm fitting hole that is fitted to the motor shaft 1 and is press-fitted and fixed to the motor shaft 1 in the worm fitting hole. A first reduction gear portion 27 is engaged with the worm 7. The first reduction gear unit 27 can be constituted by a single helical gear 29 that constitutes a worm wheel, and the helical gear 35 can be directly meshed with the helical gear 29. In the illustrated configuration, in order to achieve a predetermined reduction ratio, a helical gear 29 having a smaller number of teeth is integrally coupled to the helical gear 29 constituting the worm wheel, and the helical gear 30 is coupled to the helical gear 30. The helical gear 35 at the stage is engaged. In this way, by connecting the helical gear 30 integrally, a larger reduction ratio can be easily achieved.
[0013]
An output shaft 32 is coupled to the center of the second-stage helical gear 35. The drive torque output from the motor unit is transmitted from the motor shaft 1 to the worm 7, and the drive torque from the worm 7 to the helical gear 29 in the reduction gear unit and from the helical gear 30 integrated therewith to the second-stage helical gear 35. The torque is taken out from the output shaft 32 to the outside.
[0014]
Such a two-stage reduction configuration can be configured to reduce the helical gear diameter constituting the worm wheel that meshes with the worm 7 at the same reduction ratio as compared with the one-step reduction configuration, so that the load connected to the output shaft 32 (use) It is possible to sufficiently shorten the axial length of the small motor with a reduction gear while satisfying the reduction ratio required by the above. In short, depending on the application, a small motor with a reduction gear with a short axial length is required due to space restrictions to be mounted, but the exemplified small motor with a reduction gear can meet such a requirement. However, in the two-stage reduction configuration, it is unavoidable that the dimension in the direction perpendicular to the shaft becomes longer, but this also means that there is a sufficient margin in the direction perpendicular to the shaft as a mounting space for the brush assembly and the like. is doing.
[0015]
The illustrated configuration is not directly supported on the first stage shaft 34 integrally formed with the speed reducer portion housing 26 made of synthetic resin as the bearing portion of the first reduction gear portion 27. A bearing sleeve 33 is interposed between the first-stage gear configuration. The bearing sleeve 33 is a hollow cylindrical body having an inner peripheral surface that is prevented from rotating with respect to the first-stage shaft 34, and an outer peripheral surface that supports the first reduction gear portion 27 by slidingly supporting it. Made up. When the bearing sleeve 33 is finally assembled, a non-rotating locking portion is provided so that the bearing sleeve 33 does not slide and move with respect to the first-stage shaft 34 inside thereof. 34 are fitted into grooves provided at corresponding positions. In short, when the bearing sleeve 33 is assembled, its outer peripheral surface functions as a bearing for the rotating first reduction gear portion instead of the shaft 34.
[0016]
Next, a rotation detecting device which is a feature of the present invention and which is attached to a motor unit, in particular, a brush assembly will be described based on an example. FIG. 5 is a view for explaining the relationship between the brush assembly to which the terminal cover 19 is attached and the end bell 6. FIG. 6 is a diagram illustrating the relationship between the commutator portion and the brush portion of the rotor, with the other components removed, and FIG. 7 is a diagram similar to FIG. It is the figure which attached the cover 19. FIG. FIG. 8 is a diagram illustrating the brush assembly, and FIG. 9 is a diagram illustrating one of the terminals (for rotation detection) 13 used in the brush assembly.
[0017]
The small motor of the present invention can be the same as the conventional configuration except for the brush assembly to which the rotation detecting device is attached and the configuration related thereto. That is, the case 25 (see FIG. 1) is formed into a hollow cylindrical shape with a bottom using a metal material, and a magnet as a stator magnetic pole is attached. A yoke is attached to the outer periphery of the metal case 25. The rotor 5 (see FIG. 6) is configured by integrally assembling a rotor magnetic pole and commutator 3 constituted by a laminated core 2 and windings (not shown) on a shaft 1. The rotor 5 is rotatably supported by bearings respectively provided on the bottom of the metal case and the end bell 6. The electric current supplied from the external power source through the brush and the commutator flows in the winding wound around the rotor magnetic pole, so that the motor can rotate. The above configuration and operation are normal, and further detailed description is omitted.
[0018]
After inserting the rotor 5 integrally assembled on the shaft 1 from the opening of the bottomed hollow cylindrical metal case 25, the resin end bell 6 is fitted so as to close the opening of the metal case 25. . In this state, the extension of the shaft 1 to which the worm is to be attached is protruded from the bottom of the metal case, and the rotor 5 is rotatably supported. However, the brush is still in contact with the commutator 3. Absent.
[0019]
As seen particularly in FIG. 5, the end bell 6 is provided with an opening constituted by an integrally formed resin side wall extending in a direction perpendicular to the shaft axial direction. The brush assembly 11 including the brush holder 18 that supports the brush arm 15 to which the carbon brush 16 is attached is fitted and attached to the end bell opening. Thus, when the brush assembly 11 is fitted and attached in a direction perpendicular to the shaft axial direction, the carbon brush 16 is disposed so as to abut on the commutator 3.
[0020]
In particular, as seen in FIG. 8, a pair of brush arms 15 penetrates a brush holder 18 that can be integrally formed of synthetic resin, and a pair of terminals (for power supply) 14 for external connection. Electrically and mechanically. Since it comprised in this way, when the brush assembly 11 is inserted and attached to an end bell opening part, and a waterproof function is required, the fitting part of the case 25 and the end bell 6, and the end bell 6 and the terminal part A waterproof function can be easily obtained simply by mounting a seal member such as a seal packing. The brush holder 18 can be fitted with a terminal cover 19 that also functions as a guide for a connector connected to the terminal (see FIG. 5 or FIG. 7).
[0021]
As described above, the brush assembly 11 is basically configured to supply power to the motor unit from the external power source through the pair of carbon brushes and further through the commutator. The main feature of the rotation detection device is attached above.
[0022]
First, as shown in FIG. 6, the ring-shaped or cylindrical rotation detection magnet 4 fitted on the shaft 1 is opposite to the rotor magnetic pole (laminated core 2) with respect to the commutator 3 in the shaft axial direction. On the side and adjacent to or near the commutator 3. The rotation detecting magnet 4 has its outer peripheral surface magnetized with two poles in the circumferential direction or even poles of four or more poles.
[0023]
When the rotation detecting magnet 4 rotates with the rotation of the motor, the Hall element 17 provided at the stationary position so as to oppose it detects it as a change in magnetic flux and outputs a pulse signal corresponding to the rotation speed. In order to do this, as seen in particular in FIG. 8, the brush assembly 11 is provided with a pair of Hall elements 17, a printed circuit board 12, and four terminals (for rotation detection) 13. FIG. 9 shows one of the terminals 13 fitted and fixed in a recess provided in the brush holder 18. Such a terminal can be used in common for the four terminals by using the same terminal on both the left and right sides by turning upside down. This facilitates component management.
[0024]
10A and 10B are diagrams showing details of the printed circuit board 12. FIG. 10A shows a printed pattern diagram, and FIG. 10B shows a circuit diagram of a rotation detection circuit. The printed circuit board 12 is for wiring for supplying current to the two Hall elements and taking out signals from the two Hall elements. However, the circuit illustrated is provided with a circuit for measures against electric noise. Rotation can be detected with only one Hall element, but rotation can be achieved by placing two Hall elements between each other with a relative angular spacing, eg 90 °, relative to the shaft axis. It becomes possible to detect not only the speed but also the rotation direction. Also, by providing two hall elements, even if one fails, it is possible to detect at least rotation, so there is a risk that the motor control circuit will determine that the motor itself is not operating even during motor operation. Disappear.
[0025]
The two Hall elements 17 are formed integrally with a brush holder 18 made of synthetic resin so as to face each other with a slight gap at a position facing the rotation detection magnet 4 provided on the shaft 1. It is attached to the hall element support part 20 which can be (refer FIG. 8). The two Hall elements 17 are provided at positions adjacent to the carbon brush 16 in the shaft axial direction (vertical direction in FIG. 8). Further, on the opposite side of the hall element 17 from the carbon brush 16 in the shaft axis direction, adjacent to the hall element 17, the printed circuit board 12 is attached to the hall element support portion 20 via a plurality of columns 21. ing.
[0026]
Lead wires from the respective three terminals of the Hall element 17 are soldered to a rotation detection circuit on the printed circuit board 12. Further, the detection signal terminals (OUT1, OUT2) from each of the two Hall elements 17 and the four terminals on the printed circuit board 12 including the power supply terminal (Vcc) and the ground terminal (GND) are respectively terminals (for rotation detection). ) Soldered to the end of 13.
[0027]
As described above, the configuration for detecting rotation including the Hall element 17 and the printed circuit board 12 is arranged adjacent to the power supply configuration including the carbon brush 16 to be mechanically configured as one unit (brush assembly). In addition to being able to do this, the terminals 13, 14 can also be arranged adjacent to each other, so that the connectors connected to these terminals can also be configured in one unit. Even when a waterproof seal is applied, there is only one common place.
[0028]
【The invention's effect】
According to the present invention, the brush assembly is configured to be inserted into the end bell opening in a direction perpendicular to the shaft axial direction, so that a sufficient space is secured in the brush assembly, and the main configuration of the rotation detection device is disposed in this space. As a result, the rotation detection device can be attached to the motor side instead of the worm speed reducer side.
[0029]
As a result, the present invention can provide a small motor with a worm reducer in which the motor power supply configuration and the wiring configuration for rotation detection are integrated to make the overall configuration compact.
[0030]
In the present invention, since the main configuration of the rotation detection device is arranged in the brush assembly, most parts other than the brush assembly are a small motor with a worm reduction gear that does not require the rotation detection device. There is an effect that the parts can be shared and the management of the parts becomes easy.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the overall appearance of a small motor with a reduction gear to which the present invention is applied.
FIG. 2 is a view of the same small motor as in FIG. 1, but showing a commutator portion and a brush portion in sliding contact with the commutator portion in cross section.
FIG. 3 is a diagram showing, in partial cross section, a small motor with a reduction gear to which the present invention is applied, and FIG. 3 (A) is an overall configuration diagram showing in partial cross section when the motor shaft is viewed in the lateral direction; B) is a cross-sectional side view cut at the reduction gear section.
4 is an overall perspective view of the small motor with a speed reducer shown in FIG. 3, but some components are not shown in order to facilitate understanding of the operation.
FIG. 5 is a view for explaining the relationship between a brush assembly to which a terminal cover is attached and an end belt.
FIG. 6 is a diagram showing a configuration other than that in order to show a relationship between a commutator portion and a brush portion of a rotor.
7 is a view similar to FIG. 6, but with a terminal cover 19 attached thereto. FIG.
FIG. 8 is a diagram illustrating a brush assembly.
FIG. 9 is a diagram illustrating one of terminals (for rotation detection) 13 used in the brush assembly.
10A and 10B are diagrams showing details of the printed circuit board 12. FIG. 10A is a printed pattern diagram, and FIG. 10B is a circuit diagram of a rotation detection circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft 2 Laminated core 3 Commutator 4 Rotation detection magnet 5 Rotor 6 End bell 7 Worm 8 Bearing part 11 Brush assembly 12 Printed circuit board 13 Terminal (for rotation detection)
14 Terminal (for power supply)
15 Brush arm 16 Carbon brush 17 Hall element 18 Brush holder 19 Terminal part cover 20 Hall element support part 21 Strut 25 Case 26 Reducer part housing 27 First reduction gear part 28 Second reduction gear part 29 Helical gear 30 Helical gear 32 Output Shaft 33 Bearing sleeve 34 First stage shaft 35 Helical gear

Claims (3)

An end bell fitted so as to close an opening of a bottomed hollow cylindrical metal case to which a stator magnetic pole is attached, and a shaft rotatably supported by bearings provided on the bottom of the metal case and the end bell, respectively. A worm and a worm that are press-fitted and fixed to a shaft of the small motor, and a small motor having a rotor that is configured by integrally assembling the rotor magnetic pole and the commutator, and two brushes that abut on the commutator. In the rotation detection device that detects the rotation of the small motor with the worm reduction gear that outputs the driving torque from the small motor via the worm reduction gear including the wheel,
The end bell is provided with an opening formed by a side wall extending in a direction perpendicular to the motor shaft axial direction, and the two brushes are inserted into the end bell opening in a direction perpendicular to the shaft axial direction. A brush assembly configured to abut on the commutator and having a pair of first terminals for supplying power to the two brushes;
On the shaft, a rotation detecting magnet is provided adjacent to or in the vicinity of the commutator,
Provided in the brush assembly is a Hall element that is in a stationary position relative to the rotation detection magnet and detects a magnetic flux that changes as the rotation detection magnet rotates and outputs a rotation detection signal.
The brush assembly further includes a printed circuit board having wiring for supplying a current to the Hall element and taking out a signal therefrom, and a plurality of second wirings for connecting the wiring on the printed circuit board to the outside of the motor. With a terminal of
A rotation detection device for a small motor with a worm reduction gear. The rotation detection of the small motor with a worm reducer according to claim 1, wherein the first terminal and the second terminal of the brush assembly are disposed adjacent to each other, and external connection is enabled by a single connector to the terminals. apparatus. The worm reducer includes a second reduction gear portion that meshes with a first reduction gear portion including the worm wheel, and takes out torque from an output shaft coupled to the center of the second reduction gear portion. The rotation detection apparatus of the small motor with a worm reduction gear of Claim 1 or 2 comprised.

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