JP2003164113A - Rotation detector for small-sized motor equipped with worm reducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a structure compact in size as a whole by securing a space sufficient for mounting a rotation detector, mounting the detector therein, and integrating a motor feed structure and a wiring structure for rotation detection. <P>SOLUTION: There is provided a brush assembly that is inserted in an opening formed at an end bell fixed to the opening of a metal case so as to close it in an orthogonal direction relative to the axial direction of a shaft. Two brushes are mounted to the brush assembly so as to abut on a rectifier, and a pair of first feeding terminals are equipped to the assembly. A rotation detection magnet is mounted to the shaft so as to be adjacent to the rectifier. A Hall element that outputs a rotation detection signal is mounted to the brush assembly. There are further mounted to the brush assembly: a printed board which feeds a current to the Hall element and in which wiring for taking out a signal from the element is performed; and a plurality of second terminals for external connection. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device in a small motor with a worm speed reducer used for elevating a window glass of an automobile, for example.

[0002]

2. Description of the Related Art Conventionally, a small motor with a worm reducer has been used for raising and lowering a window glass of an automobile. The rotational power of the motor shaft raises and lowers the window glass through the worm and the worm wheel, and further through the glass raising and lowering mechanism connected to the output shaft thereof. In order to detect the position and speed of the window glass, a rotation detecting device is integrally incorporated in a small motor with a worm speed reducer. Such a rotation detecting 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 the two corresponding to the motor rotation. Since it is detected by the Hall element and is generated as a pulse signal, it is necessary to provide a space for mounting such a rotation detecting device and wiring for supplying current to the Hall element and extracting a signal. Become.

Conventionally, there is not enough space for mounting the rotation detecting device on the motor side of such a small motor with a worm reducer, and therefore the rotation detecting device is mounted on the worm reducer side. JP-A-6-217
Japanese Unexamined Patent Publication No. 497 discloses such a technique, which requires that a magnetic plate having magnetic poles magnetized alternately on the circumference is attached to a worm wheel output shaft on the worm reducer side.

[0004]

When the rotation detecting device is mounted on the worm speed reducer side, the wiring structure for supplying current to the Hall element and extracting a signal is not the structure for supplying power to the motor. There is a problem that it is needed separately.

Therefore, an object of the present invention is to solve such a problem and to secure a sufficient space for mounting the rotation detecting device on the motor side and mount it there.

Accordingly, an object of the present invention is to provide a small motor with a worm gear reducer in which the motor power feeding structure and the wiring structure for rotation detection are integrated to make the entire structure compact.

[0007]

SUMMARY OF THE INVENTION A rotation detecting 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. A rotor formed by integrally assembling a rotor magnetic pole and a commutator on a shaft rotatably supported by bearings provided on the bottom of the metal case and the end bell, and abutting on the commutator 2 A small motor with two brushes. Then, the driving torque from the small motor is output through a worm speed reducer including a worm and a worm wheel that are press-fitted and fixed 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 axial direction of the motor shaft, and the end bell opening is inserted in a direction perpendicular to the axial direction of the shaft. It is configured to abut on the child,
A brush assembly is provided with a pair of first terminals for powering the two brushes. A rotation detecting magnet is provided on the shaft adjacent to or in the vicinity of the commutator. A Hall element is provided in the brush assembly at a stationary position facing the rotation detecting magnet, and detects a magnetic flux that changes as the rotation detecting 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 wiring boards for connecting the wiring on the printed circuit board to the outside of the motor. And a terminal.

Further, the first terminal and the second terminal of the brush assembly are arranged adjacent to each other, and the terminals can be externally connected by a single connector.

Further, the worm speed reducer is provided with a second speed reduction gear part which meshes with a first speed reduction gear part including a worm wheel, and a torque is externally applied from an output shaft connected to the center of the second speed reduction gear part. Configure to take out.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on examples. FIG. 1 is a diagram illustrating the appearance of the entire small motor with reduction gear 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 unit and a speed reducer unit that are integrally connected by screws or the like. The speed reducer unit has a two-stage speed reduction configuration including a first speed reduction gear unit 27 and a second speed reduction gear unit 28. First, the configuration of the speed reducer unit will be described with reference to FIGS. 3 and 4.

FIG. 3 is a partial cross-sectional view of a small motor with a reduction gear to which the present invention is applied, and FIG. 3A is an overall configuration diagram showing a partial cross-section of a motor shaft in a lateral direction. Yes, (B) is a cross-sectional side view taken along the reducer section. FIG. 4 is an overall perspective view of the small motor with a reducer shown in FIG. 3, but a part of the configuration is omitted for easy understanding of the operation.

In these figures, the motor portion is attached to the reduction gear portion via a screw, and the tip end portion of the motor shaft 1 is fixed by a bearing portion 8 provided in a reduction gear portion housing 26. The worm 7 has a worm fitting hole that fits into 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 meshed with the worm 7. The first reduction gear unit 27 can be configured by a single helical gear 29 that constitutes a worm wheel, and it is also possible to directly mesh the helical gear 29 with the second-stage helical gear 35. In the illustrated configuration, in order to achieve a predetermined reduction gear ratio, a helical gear 29 forming a worm wheel is integrally coupled with a helical gear 30 having a smaller number of teeth and a smaller diameter, and the helical gear 30 is connected to the helical gear 30. The helical gear 35 of the step is meshed. By integrally connecting the helical gears 30 in this manner, a larger reduction ratio can be easily achieved.

The output shaft 32 is connected to the center of the second stage helical gear 35. The drive torque output from the motor section is transmitted from the motor shaft 1 to the worm 7, and the worm 7 and the helical gear 29 are transmitted in the reduction gear section.
Then, the driving torque is transmitted from the helical gear 30 integrated therewith to the second-stage helical gear 35, and the torque is taken out from the output shaft 32 to the outside.

In contrast to the one-step speed reduction structure, such a two-step speed reduction structure can reduce the diameter of the helical gear forming the worm wheel that meshes with the worm 7 at the same speed reduction ratio, so that the load connected to the output shaft 32 can be reduced. It is possible to sufficiently reduce the axial length of the small motor with a reduction gear while satisfying the reduction ratio required by (use). In short, depending on the application, due to the space restrictions to be implemented,
A small motor with a reducer with a short axial length is required,
The illustrated small motor with a reducer can meet such a demand. However, in the two-stage deceleration configuration, the dimension in the direction perpendicular to the axis is unavoidable, but this also means that there is sufficient room in the direction perpendicular to the axis as a mounting space for the brush assembly and the like. is doing.

It should be noted that the illustrated configuration has a first reduction gear unit 27.
As a bearing of the reduction gear housing 26 made of synthetic resin
The bearing sleeve 33 is interposed between the shaft 34 and the first-stage gear structure, instead of directly supporting the first-stage shaft 34 integrally formed with the shaft. The bearing sleeve 33 is a hollow cylindrical body having an inner peripheral surface that is prevented from rotating with respect to the shaft 34 of the first stage and an outer peripheral surface that supports the first reduction gear portion 27 as a sliding shaft. Configured. This bearing sleeve 3
When 3 is finally assembled, it does not slide and move with respect to the shaft 34 of the first stage inside thereof.
A locking portion for preventing rotation is provided, and the locking portion is fitted in a groove portion provided at a corresponding position of the shaft 34. in short,
When the bearing sleeve 33 is assembled, its outer peripheral surface functions as a bearing of the rotating first reduction gear portion instead of the shaft 34.

Next, a rotation detecting device, which is a feature of the present invention and is attached to the motor portion, particularly to the brush assembly, will be described based on an example. FIG. 5 is a diagram for explaining the relationship between the end bell 6 and the brush assembly to which the terminal cover 19 is attached. FIG. 6 is a view showing the relationship between the commutator portion and the brush portion of the rotor by removing other components, and FIG. 7 is a view similar to FIG. It is the figure which attached the cover 19. FIG. 8 is a diagram illustrating a brush assembly, and FIG.
FIG. 4 is a diagram illustrating one of terminals (for rotation detection) 13 used in the brush assembly.

The miniature motor of the present invention, except for the brush assembly to which the rotation detecting device is attached and the structure related thereto,
It can be the same as the conventional configuration. That is, case 25
(See FIG. 1) is formed of a metallic material into a hollow cylindrical shape with a bottom, and a magnet as a stator magnetic pole is attached. A yoke is attached to the outer circumference of the metal case 25. The rotor 5 (see FIG. 6) is configured by integrally assembling a rotor core composed of a laminated core 2 and windings (not shown) and a commutator 3 on the shaft 1. The rotor 5 is rotatably supported by bearings provided on the bottom of the metal case and the end bell 6. The current supplied from the external power source through the brush and the commutator flows through the windings wound around the rotor magnetic poles, which allows the motor to rotate. The above-described configuration and operation are normal, and a detailed description thereof will be omitted.

After inserting the rotor 5 integrally assembled on the shaft 1 from the opening of the metal case 25 having a hollow cylindrical shape with a bottom, a resin endbell 6 is fitted so as to close the opening of the metal case 25. Be worn. In this state, the extension of the shaft 1 to which the worm is attached is projected from the bottom of the metal case to rotatably support the rotor 5, but the brush is still in contact with the commutator 3. Absent.

As can be seen in particular in FIG. 5, the endbell 6
Is provided with an opening formed by an integrally formed resin side wall extending in a direction perpendicular to the shaft axis direction. A brush assembly 11 including a brush holder 18 supporting a brush arm 15 to which a carbon brush 16 is attached is fitted and attached to the end bell opening. In this way, the brush assembly 1 is placed in a direction perpendicular to the shaft axial direction.
Carbon brush 1 when 1 is fitted and attached
6 is arranged so as to abut on the commutator 3.

In particular, as shown in FIG. 8, a brush holder 18 which can be integrally formed of synthetic resin.
A pair of brush arms 15 penetrates through and is electrically and mechanically connected to a pair of terminals (for power supply) 14 for external connection. With this configuration, when the brush assembly 11 is inserted into the end bell opening and attached, and a waterproof function is required, the fitting portion between the case 25 and the end bell 6 and between the end bell 6 and the terminal portion can be replaced. A waterproof function can be easily obtained only by installing a seal member such as a seal packing in between. Further, the brush holder 18 can be fitted with a terminal portion cover 19 which also functions as a guide for a connector connected to a terminal (see FIG. 5 or FIG. 7).

As described above, the brush assembly 11 basically has a pair of carbon brushes from an external power source.
Further, although the structure is for supplying power to the motor section through the commutator, the present invention is characterized in that the main structure of the rotation detecting device is mounted on the brush assembly 11.

First, as shown in FIG. 6, the shaft 1
Ring-shaped or cylindrical rotation-detecting magnet 4 fitted on top
However, it is provided on the side of the commutator 3 opposite to the rotor magnetic pole (the laminated core 2) in the shaft axial direction, and adjacent to or near the commutator 3. The outer peripheral surface of the rotation detecting magnet 4 is magnetized to have two poles or four or more even poles in the circumferential direction.

When the rotation detecting magnet 4 rotates as the motor rotates, the Hall element 17 provided at a stationary position so as to face the rotation detecting magnet 4 detects the change in magnetic flux and outputs a pulse signal corresponding to the rotation speed. . To do this,
In particular, as seen in FIG. 8, the brush assembly 11 includes
A pair of Hall elements 17, a printed board 12, and four terminals (for rotation detection) 13 are provided. Figure 9
Shows one of the terminals 13 fitted and fixed in the recess provided in the brush holder 18. Such terminals can be used by reversing the top and bottom so that the same terminals are used on both the left and right sides and the same terminals are used for the four terminals. This facilitates component management.

FIG. 10 is a diagram showing the details of the printed circuit board 12. FIG. 10A is a print pattern diagram, and FIG.
(B) shows a circuit diagram of the rotation detection circuit.
The printed circuit board 12 is for wiring for supplying a current to the two Hall elements and taking out a signal from the two Hall elements, but the circuit illustrated has an electric noise countermeasure circuit added thereto. Rotation can be detected by only one Hall element, but rotation can be achieved by arranging two Hall elements with respect to the shaft axis with a relative angular interval between each other, for example 90 °. It becomes possible to detect not only the speed but also the direction of rotation. Further, by providing two Hall elements, at least rotation detection is possible even if one fails, so there is no possibility that the motor control circuit determines that the motor itself is not operating even while the motor is operating. Lost.

The two Hall elements 17 are integrated with the brush holder 18 made of synthetic resin so as to face the rotation detecting magnet 4 provided on the shaft 1 with a slight gap therebetween. It is attached to the Hall element supporting portion 20 that can be formed in the above (see FIG. 8).
Further, 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, the printed circuit board 12 is attached to the Hall element supporting portion 20 on the side opposite to the carbon brush 16 of the Hall element 17 in the axial direction of the shaft, adjacent to the Hall element 17 via a plurality of columns 21. ing.

The lead wires from each of the three terminals of the hall element 17 are soldered to the rotation detection circuit on the printed board 12. Further, the detection signal terminals (OUT1 and OUT2) from 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). ) 13 is soldered to the end.

As described above, by arranging the structure for detecting rotation including the Hall element 17 and the printed circuit board 12 adjacent to the power supply structure including the carbon brush 16,
Not only can it be mechanically configured as one unit (brush assembly), but also each terminal 1
Since the terminals 3 and 14 can be arranged adjacent to each other, it is possible to configure the connectors for connecting these terminals into one unit. Even when applying a waterproof seal, there is only one common place.

[0028]

As described above, according to the present invention, the brush assembly is configured to be inserted into the opening of the end bell in the direction perpendicular to the axial direction of the shaft, so that a sufficient space is secured in the brush assembly and the rotation detecting device is provided in this space. By arranging the main configuration of the above, it becomes possible to attach the rotation detecting device to the motor side instead of the worm reducer side.

As a result, the present invention makes it possible to provide a small motor with a worm reducer in which the motor power feeding configuration and the wiring configuration for rotation detection are integrated to make the overall configuration compact.

Further, according to the present invention, since the main components of the rotation detecting device are arranged in the brush assembly, most of the parts other than the brush assembly are equipped with the worm speed reducer which does not require the rotation detecting device. The parts can be shared with the small motor, and the parts can be easily managed.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an external appearance of an entire 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 the commutator section and the brush section in sliding contact therewith in cross section.

FIG. 3 is a partial cross-sectional view of a small motor with a reducer to which the present invention is applied, and FIG. 3A is an overall configuration diagram showing a partial cross-section of a motor shaft in a lateral direction; B)
[Fig. 4] is a cross-sectional side view taken along the reducer section.

FIG. 4 is an overall perspective view of the small motor with a reducer shown in FIG. 3, but part of the configuration is omitted for easy understanding of the operation.

FIG. 5 is a diagram for explaining the relationship between a brush assembly to which a terminal cover is attached and an end belt.

FIG. 6 is a view with other components removed to show the relationship between the commutator portion and the brush portion of the rotor.

7 is a view similar to FIG. 6 but with a terminal cover 19 attached thereto.

FIG. 8 is a diagram illustrating a brush assembly.

FIG. 9 is a diagram illustrating one terminal (for rotation detection) 13 used in the brush assembly.

FIG. 10 is a diagram showing details of the printed circuit board 12,
(A) shows a printed pattern diagram, and (B) shows a circuit diagram of a rotation detection circuit.

[Explanation of symbols]

1 shaft 2 laminated core 3 commutator 4 Rotation detection magnet 5 rotor 6 end bell 7 warm 8 bearing 11 brush assembly 12 printed circuit boards 13 terminals (for rotation detection) 14 terminals (for power supply) 15 brush arm 16 carbon brush 17 Hall element 18 brush holder 19 Terminal cover 20 Hall element support 21 props 25 cases 26 Reducer housing 27 First reduction gear unit 28 Second reduction gear unit 29 Helical gear 30 helical gear 32 output shaft 33 Bearing sleeve 34 First axis 35 helical gear

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Claims (3)

[Claims] 1. An end bell fitted to close an opening of a bottomed hollow cylindrical metal case to which a stator magnetic pole is attached, and rotatably supported by bearings provided on the bottom and end bell of the metal case, respectively. A small motor having a rotor formed by integrally assembling a rotor magnetic pole and a commutator on a supported shaft, and a small motor having two brushes abutting on the commutator, is press-fitted and fixed to the shaft of the small motor. In the rotation detecting device for detecting the rotation of the small motor with the worm reducer that outputs the driving torque from the small motor through the worm reducer including the worm and the worm wheel, the end bell is not in the axial direction of the motor shaft. An opening composed of a side wall extending in a right angle direction is provided, and the end bell opening is inserted in a direction perpendicular to the shaft axial direction. And a brush assembly having a pair of first terminals for supplying electric power to the two brushes, the two brushes abutting on the commutator when inserted. A rotation detecting magnet is provided above or adjacent to the commutator, and it detects a magnetic flux that changes as the rotation detecting magnet rotates at a stationary position facing the rotation detecting magnet. A Hall element that outputs a rotation detection signal is provided in the brush assembly, and the brush assembly further includes a printed circuit board having wiring for supplying a current to the Hall element and extracting a signal therefrom. A rotation detecting device for a small motor with a worm speed reducer, comprising: a plurality of second terminals for connecting wiring on the printed circuit board to the outside of the motor. 2. The worm gear reducer according to claim 1, wherein the first terminal and the second terminal of the brush assembly are arranged adjacent to each other, and the terminals can be externally connected by a single connector. Small motor rotation detection device. 3. The worm reducer includes a second reduction gear portion that meshes with a first reduction gear portion that includes the worm wheel, and the output shaft connected to the center of the second reduction gear portion is connected to the outside. The rotation detecting device for a small motor with a worm speed reducer according to claim 1 or 2, which is configured to extract torque.