JP2007006560A - Motor with encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and low-cost motor that can acquire stable output. <P>SOLUTION: The motor is provided with a commutator 12 attached to a rotating shaft of the motor 5, a pair of brushes 13a, 13b for sliding and contacting the commutator 12, and a pulse generating means for outputting and converting a DC voltage, applied between a pair of the brushes 13a, 13b into a pulse sequence, corresponding to the rotation of the motor 5. The commutator 12 comprises a plurality of electrodes divided equally in the rotating direction of the rotating shaft. The required electrode among a plurality of the electrodes is set as an opened electrode 12a for configuring opened state between a pair of the brushes 13a, 13b. Electrodes other than the open electrode 12a are set as closed electrodes 12b, commonly connected and configuring a closed state between a pair of the brushes 13a, 13b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor with an encoder, and more particularly to a motor with an encoder that is small and compact and can be reduced in cost.

  The motor with an encoder is used, for example, for operation control of a work robot or drive control of various automatic machines. An example of such a conventional motor with an encoder is shown in FIG. In this prior art, a disk-shaped slit plate 1 having slits formed at equal intervals in the circumferential direction is attached to a rotating shaft of a motor 2, and the light emitting element 3 and a photo are sandwiched between the slit plates 1. A sensor 4 is arranged.

  When the motor 2 rotates, the light from the light emitting element 3 obtained through the slits of the rotating slit plate 1 is received by the photosensor 4 so that a pulse train signal corresponding to the rotation of the motor 2 is received from the photosensor 4. It is made to output. From this pulse train signal, the rotational speed of the motor 2 and the like are obtained.

Further, as a conventional technique related to an encoder-equipped motor, for example, the following motor driving device is known. This prior art includes a photoelectric rotation detection device configured such that a slit plate attached to a rotation shaft of a capacitor motor is positioned between a light emitting element and a light receiving element in a transmissive photosensor. When the condenser motor rotates at a low speed, the rotation speed is likely to change depending on the load. Therefore, the rotation speed as a control amount is detected by the photoelectric rotation detection device, and feedback control is performed (for example, Patent Documents). 1).
JP-A-1-318526 (second page, FIGS. 1 to 3).

  In the prior art shown in FIG. 8, the light emitting element and the photosensor are arranged so as to sandwich a disc-shaped slit plate attached to the rotating shaft of the motor. As described above, since expensive optical elements such as a light emitting element and a photosensor are used, the cost increases.

  In the prior art described in Patent Document 1, a transmissive photosensor of a composite type in which a light emitting element and a light receiving element are integrated with a space is used. For this reason, the cost is further increased as compared with the case where individual light emitting elements or photosensors are used.

  Moreover, the motor with an encoder is often used by being incorporated in various devices. For this reason, the encoder unit attached to the motor is desired to be small and compact. However, in any of the above prior arts, since the light emitting element and the photosensor are arranged so as to sandwich the slit plate, it is difficult to make the structure compact and compact.

  Thus, a technical problem to be solved in order to obtain a stable output at a small, compact, low cost in an encoder-equipped motor, and the present invention aims to solve this problem.

The present invention has been proposed to achieve the above object, and the invention according to claim 1 includes a commutator attached to a rotating shaft of a motor and a pair of brushes slidably contacting the commutator. An encoder-equipped motor having pulse generation means for converting a DC voltage applied between the brushes into a pulse train corresponding to the rotation of the motor and outputting the pulse train is provided.

  According to this configuration, the DC voltage applied between the pair of brushes is converted into a pulse train corresponding to the rotation of the motor and output in cooperation with the rotating commutator and the pair of brushes slidably in contact therewith, The rotation angle, rotation speed, and the like of the motor are obtained from the pulse train.

  According to a second aspect of the present invention, the commutator includes electrodes that are equally divided into a plurality of rotation directions of the rotating shaft, and a required electrode of the plurality of electrodes is open between the pair of brushes. There is provided an encoder-equipped motor, which is an open electrode that is set to a closed electrode, and the electrodes other than the open electrode are commonly connected to set a closed state between the pair of brushes.

  According to this configuration, specifically, the commutator is configured by an open electrode and a commonly connected closed electrode. When the open electrode contacts one of the brushes in the pair of brushes, the pair of brushes is in an open state, and when the commonly connected closed electrode contacts both brushes in the pair of brushes, the pair of brushes is closed. It becomes a state. Therefore, the switching action is caused by the open electrode and the closed electrode alternately contacting the pair of brushes. A DC voltage applied between the pair of brushes is continuously switched as the motor rotates, and a pulse train corresponding to the rotation of the motor is output.

  According to a third aspect of the present invention, when a plurality of the open electrodes are provided, the open electrodes are provided at asymmetric positions with the axis center of the rotation shaft as the center of symmetry, and the number of poles of the open electrode is N (however, , N is an integer greater than or equal to 1), a motor with an encoder that outputs the pulse train composed of N × 2 pulses per rotation of the motor is provided.

  According to this configuration, one open electrode contacts one brush and the other brush of the pair of brushes once per rotation of the motor. Therefore, one open electrode causes two open states (off state in the switching action) between a pair of brushes per one rotation of the motor. As a result, when the number of poles of the open electrode is N, N × 2 pulses are generated for each rotation of the motor.

  According to a fourth aspect of the present invention, the output terminal of the pulse train is connected to a DC voltage source via a pull-up resistor or connected to a ground potential via a pull-down resistor, and the pair of brushes are in a closed state. When set to, the pulse in the pulse train is at the L level or the motor with the encoder at the H level.

  According to this configuration, when the output terminal is connected to the DC voltage source via the pull-up resistor, a pulse that is at the L level when the pair of brushes is in the closed state (on state in the switching action). Output from the output terminal. When the output terminal is connected to the ground potential via a pull-down resistor, a pulse that is at H level is output from the output terminal when the pair of brushes is in a closed state.

The invention described in claim 1 includes a commutator attached to a rotating shaft of a motor, and a pair of brushes slidably in contact with the commutator, and a DC voltage applied between the pair of brushes corresponds to the rotation of the motor. Since the pulse generation means for converting and outputting the pulse train is provided, the encoder section is output by outputting the pulse train corresponding to the rotation of the motor by the pulse generation means including the commutator and a pair of brushes slidably contacting the commutator. There is an advantage that it can be configured to be small and compact, and cost can be reduced.

  According to a second aspect of the present invention, the commutator includes electrodes that are equally divided into a plurality of rotation directions of the rotating shaft, and a required electrode of the plurality of electrodes is open between the pair of brushes. Open electrodes to be set, and the electrodes other than the open electrodes are commonly connected to form a closed electrode between the pair of brushes, so that the open electrode and the commonly connected closed electrode are The switching action is caused by alternately contacting the pair of brushes.

  The DC voltage applied between the pair of brushes is continuously switched with the rotation of the motor, so that a pulse train corresponding to the rotation of the motor can be stably output with a small and compact configuration. There is an advantage that can be.

  According to a third aspect of the present invention, when a plurality of the open electrodes are provided, the open electrodes are provided at asymmetric positions with the axis center of the rotation shaft as the center of symmetry, and the number of poles of the open electrode is N (however, , N is an integer greater than or equal to 1), the pulse train composed of N × 2 pulses per one rotation of the motor is output. Therefore, by setting the number of poles N of the open electrodes to a required value, there is an advantage that a pulse train having a period according to the application is stably output.

  According to a fourth aspect of the present invention, the output terminal of the pulse train is connected to a DC voltage source via a pull-up resistor or connected to a ground potential via a pull-down resistor, and the pair of brushes are in a closed state. When set to, the pulse in the pulse train becomes L level or H level. Therefore, when the space between the pair of brushes is in a closed state, it is possible to stably output a pulse train composed of pulses at L level or H level depending on the application, and there is an advantage that the degree of freedom in design is increased. .

  For the purpose of obtaining a small, compact, low-cost and stable output, a commutator attached to a rotating shaft of a motor and a pair of brushes slidably contacting the commutator, the DC voltage applied between the pair of brushes is A motor with an encoder having pulse generation means for converting to a pulse train corresponding to the rotation of the motor and outputting the pulse train, wherein the commutator is constituted by a plurality of electrodes equally divided in the rotation direction of the rotating shaft, Among the electrodes, a required electrode is an open electrode that sets the pair of brushes in an open state, and each electrode other than the open electrode is connected in common and a closed electrode that sets the pair of brushes in a closed state In addition, when there are a plurality of the open electrodes, the asymmetric position with the axis center of the rotation axis as the center of symmetry When the number of poles of the open electrode is N, the pulse generating means outputs a pulse train consisting of N × 2 pulses per one rotation of the motor, and the output terminal of the pulse train is Whether it is connected to a DC voltage source via a pull-up resistor or connected to a ground potential via a pull-down resistor, and the pulse in the pulse train is set to L level when the pair of brushes is set in a closed state Or by setting it to H level. The present invention can increase the number of output pulses per motor rotation by increasing the number of electrodes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the motor with an encoder according to the present embodiment will be described. This embodiment uses a pair of commutators and brushes, with one of the three electrodes being electrically open and the other two being electrically closed, thereby rotating the rotor one revolution. In contrast, two pulse outputs can be obtained.

  1 is a partial cross-sectional front view of a motor with an encoder, FIG. 2 is a circuit diagram, and FIG. 1A is a diagram showing a case where an output terminal is connected to a DC voltage source through a pull-up resistor. (B) is a diagram showing a case where the output terminal is connected to the ground potential via a pull-down resistor, and FIGS. 3 (A) to (F) are a pair of motors with the rotation of the motor when the number of commutator electrodes is three. It is a set figure which shows the mode of the on / off switching between brushes.

  In FIG. 1, an encoder portion 8 is attached to an extension portion of a rotating shaft 7 to which a rotor 6 in a motor 5 is attached. An encoder substrate 9 is provided on the side close to the motor 5 in the encoder unit 8, and an encoder commutator 12 is attached to the rotating shaft 7 in addition to the commutator 10 and the brush 11 inside the motor 5. A pair of brushes 13 a and 13 b that are in sliding contact with the commutator 12 are provided. The pair of brushes 13a and 13b are supported by the encoder board 9. The commutator 12 is provided with a connection substrate or wire (conducting wire; hereinafter simply referred to as a connection wire) 14 for commonly connecting closed electrodes described later. The encoder unit 8 described above is covered with an encoder cover 15.

  As shown in FIGS. 2 and 3, the commutator 12 is composed of electrodes (commutator segments) equally divided into a plurality (three in the illustrated example) in the rotation direction of the rotating shaft 7. Of the electrodes, a required electrode is an open electrode 12a that sets an open (off) state between the pair of brushes 13a and 13b. The electrodes other than the open electrode 12a are closed electrodes 12b and 12b that are connected in common by the common connection wire 14 and set the pair of brushes 13a and 13b in a closed (on) state.

  As described above, the commutator 12 including the open electrode 12a and the commonly connected closed electrodes 12b and 12b turns on and off the pair of brushes 13a and 13b that are in sliding contact with the motor 5 as the motor 5 rotates. Has a switching function.

  Therefore, the pulse generating means is configured by including the commutator 12 and the pair of brushes 13 a and 13 b that are in sliding contact with the commutator 12. The pulse generating means converts the DC voltage Vcc from the DC voltage source 16 applied between the pair of brushes 13 a and 13 b into a pulse train corresponding to the rotation of the motor 5 and outputs it from the output terminal 17. A drive circuit 18 is connected to the motor 5.

In the circuit example of FIG. 2 (A), is connected to the output terminal 17 to the one brush 13a, to the output terminal 17, a DC voltage source 16 is connected via a pull-up resistor R _1. The other brush 13b is directly connected to the ground potential GND. Therefore, in this circuit example, when the pair of brushes 13a and 13b is in the ON state, a pulse train composed of pulses at L level is output from the output terminal 17. The front of the output terminal 17, the resistor R ₂ and a filter circuit comprising a low pass filter composed are connected by capacitor C, and filter the high frequency components such as noise, configured as stable pulse train output is obtained Has been.

On the other hand, in the circuit example of FIG. 2B, the DC voltage source 16 is directly connected to one brush 13a, and the output terminal 17 is connected to the other brush 13b. The output terminal 17 is connected to the ground potential GND through a pull-down resistor R _3. Therefore, in this circuit example, when the pair of brushes 13a and 13b is in the ON state, a pulse train composed of pulses that become H level is output from the output terminal 17. A filter circuit composed of a low-pass filter similar to the above is connected to the preceding stage of the output terminal 17.

Here, in FIGS. 2A and 2B, the circuit portion on the A side can be mounted on the motor 5, but it can also be mounted on a set using the motor with the encoder. In that case, only four wires are required for a set or the like. In contrast, in the case of the photoelectric type shown in FIG. 8, two for the motor, Vcc power supply line, GND line, and five output lines are absolutely necessary.

  Next, the operation of the motor with an encoder configured as described above will be described with reference to the assembly diagrams of FIGS. In FIG. 3, first, the open electrode 12a is positioned on the lower side, and the commonly connected closed electrodes 12b and 12b are in contact with both brushes 13a and 13b, respectively. Then, between the pair of brushes 13a and 13b is in a closed (on) state. As the motor 5 rotates (counterclockwise in FIG. 3), when the open electrode 12a contacts the other brush 13b, the pair of brushes 13a and 13b is switched to an open (off) state.

  Then, the motor 5 rotates approximately 180 ° so that the open electrode 12a located on the lower side is located on the upper side, and the closed electrodes 12b and 12b connected in common again contact the brushes 13a and 13b, respectively. Then, between the pair of brushes 13a and 13b is in a closed (on) state.

  Thereafter, when the motor 5 further rotates and the open electrode 12a comes into contact with one brush 13a, the pair of brushes 13a and 13b is again switched to the open (off) state.

  Thus, the total number of electrodes equally divided in the commutator 12 is three, of which one is the open electrode 12a and the two closed electrodes 12b and 12b are connected in common. In this case, the closed electrodes 12b and 12b connected in common with each rotation of the motor 5 are in contact with the brushes 13a and 13b twice. Further, one open electrode 12a is in contact with one brush 13a and the other brush 13b once each.

  As a result, an on / off / on / off switching action occurs per rotation of the motor 5, and two pulses are generated per rotation of the motor 5 by this switching action with respect to the DC voltage Vcc. At this time, the ratio of the on time per cycle is 33%, and the ratio of the off time is 66%.

  2 and 3, the number of poles of the open electrode 12a is one. When the number of poles of the open electrode 12a is generally N (where N is an integer of 1 or more), N × 2 pulses are generated per rotation of the motor 5. However, as shown in FIGS. 5, 6, and 7 to be described later, when a plurality of poles of the open electrode 12 a are provided, the plurality of open electrodes 12 a have the axis of the motor rotation shaft 7 ( It is a condition that it is provided at an asymmetrical position as a symmetric center point.

  As the motor 5 continuously rotates, the DC voltage Vcc applied between the pair of brushes 13a and 13b is continuously switched. In the circuit example of FIG. 2A, between the pair of brushes 13a and 13b. When the signal is in the ON state, a pulse train composed of pulses at the L level is output from the output terminal 17. Further, in the circuit example of FIG. 2B, when the pair of brushes 13a and 13b is in an ON state, a pulse train including a pulse that is set to H level is output from the output terminal 17.

  Next, modified examples of the total number of divided electrodes, the number of open electrodes, and the number of closed electrodes commonly connected in the commutator will be described with reference to FIGS.

4A to 4D, the total number of electrodes equally divided in the commutator 12 is four, of which one open electrode 12a and three closed electrodes 12b,... Are connected in common. The modified example is shown. In this modified example, two (N = 1, 1 × 2) pulses are generated per one rotation of the motor 5. The on / off ratio in the switching action is 50%.

  5A to 5H, the total number of electrodes equally divided in the commutator 12 is eight, of which two open electrodes 12a and six closed electrodes 12b, 12b,... The modification connected in common is shown. The two open electrodes 12 a and 12 a are provided at asymmetric positions with the axis center of the motor rotation shaft 7 as the center of symmetry. In this modification, four (N = 2, 2 × 2) pulses are generated per rotation of the motor 5. The on / off ratio in the switching action is 50%.

  6 (A) to 6 (L), the total number of electrodes equally divided in the commutator 12 is twelve, of which three open electrodes 12a and nine closed electrodes 12b, 12b,... The modification connected in common is shown. The three open electrodes 12a,... Are provided at asymmetric positions with respect to the axis center (symmetric center point) of the motor rotation shaft 7. In this modification, 6 pulses (N = 3, 3 × 2) are generated per rotation of the motor 5. The on / off ratio in the switching action is 50%.

  FIGS. 7A to 7L are modified examples of FIGS. 6A to 6L. In this modification, one of the three open electrodes 12a,... In FIGS. 6 (A) to 6 (L) is opened 180.degree. On the opposite side. It has been moved. Since the two brushes 13a and 13b are positioned on the opposite sides of 180 °, even when the open electrode 12a is moved to the opposite side of 180 °, the operation for setting the pair of brushes 13a and 13b to be off is the same. .

  As described above, in the motor with an encoder according to this embodiment, the encoder unit 8 can be configured to be small and compact, and the cost can be reduced. Further, the DC voltage Vcc applied between the pair of brushes 13a and 13b is continuously switched with the rotation of the motor 5, so that a pulse train corresponding to the rotation of the motor 5 can be generated with a small and compact configuration. Stable output can be achieved.

  By setting the number of poles N of the open electrode 12a (where N is an integer of 1 or more) to a required value, a pulse train having a period according to the application can be stably output. Further, when the pair of brushes 13a and 13b is in a closed state, it is possible to stably output a pulse train composed of pulses at L level or H level depending on the application.

  In the circuits shown in FIGS. 2A and 2B, when the circuit portion on the A side is attached to a set using an encoder-equipped motor, only four wires are required for the set. On the other hand, in the case of the photoelectric type shown in FIG. 8, two for the motor, Vcc power supply line, GND line, and five output lines are required. Therefore, it is possible to reduce the size in this respect.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The partial cross section front view which shows the structure of the motor with an encoder which concerns on the Example of this invention. The circuit diagram of the said Example. (A) shows the case where the output terminal is connected to a DC voltage source via a pull-up resistor, and (B) shows the case where the output terminal is connected to a ground potential via a pull-down resistor. In the said Example, the modification when the number of electrodes of a commutator is set to 3 is shown, (A)-(F) is a set figure which shows the mode of the on / off switching between a pair of brushes accompanying rotation of a motor. In the said Example, the modification when the number of electrodes of a commutator is set to 4 is shown, (A)-(D) is a set figure which shows the mode of the on / off switching between a pair of brushes accompanying rotation of a motor. In the said Example, the modification when the number of electrodes of a commutator is set to 8 is shown, (A)-(H) is a set figure which shows the mode of the on / off switching between a pair of brushes accompanying rotation of a motor. In the said Example, the modification example when the number of electrodes of a commutator is set to 12 is shown, (A)-(L) is a set figure which shows the mode of the on / off switching between a pair of brushes accompanying rotation of a motor. In the above embodiment, the number of electrodes of the commutator is 12 and the arrangement of the open electrodes in the configuration of FIG. 6 is changed. (A) to (L) are accompanied by the rotation of the motor. The group figure which shows the mode of the on / off switching between a pair of brushes. The circuit diagram of the conventional motor with an encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Motor 7 Rotating shaft 8 Encoder part 12 Commutator 12a Open electrode 12b Closed electrode 13a, 13b Brush 14 Connection wire 16 DC voltage source 17 Output terminal R ₁ Pull-up resistance R ₃ Pull-down resistance

Claims (4)

  A pulse having a commutator attached to a rotating shaft of a motor and a pair of brushes slidably contacting the commutator, and converting a DC voltage applied between the pair of brushes into a pulse train corresponding to the rotation of the motor and outputting the pulse A motor with an encoder, characterized by comprising generating means.   The commutator is composed of electrodes equally divided into a plurality of rotation directions of the rotating shaft, and among the plurality of electrodes, a required electrode is an open electrode that sets an open state between the pair of brushes, 2. The motor with an encoder according to claim 1, wherein each electrode other than the open electrode is a closed electrode that is connected in common and sets a closed state between the pair of brushes.   When a plurality of the open electrodes are provided, the open electrodes are provided at asymmetric positions with the axis center of the rotation axis as the center of symmetry, and the number of poles of the open electrodes is N (where N is an integer of 1 or more). 3. The motor with an encoder according to claim 1, wherein the pulse train composed of N × 2 pulses is output per one rotation of the motor. The output terminal of the pulse train is connected to a DC voltage source via a pull-up resistor or connected to a ground potential via a pull-down resistor, and the pulse train is set when the pair of brushes is set in a closed state. The motor with an encoder according to claim 1, 2 or 3, wherein the pulse at becomes an L level or an H level.

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