KR900007103B1 - Motor - Google Patents

Abstract

The motor (30) includes stator (34) mounted in casing (32); rotating shaft (36) mounted at the center of the casing supported by bearing (38,40); rotator (42) fixed at the stator. The plural type resolvers (44) are composed of casing (46). The casing (46) and casing (32) of the motor are unlogrally attached. The casing (46) is joined with the casing (32) by bolts precing from cover member (47) to disk projection (43).

Description

Motor with rotary position detector

1 is a schematic explanatory view showing a state in which a motor and a double speed rotary position detector according to the prior art are combined;

FIG. 2 is a waveform diagram showing respective output divided values of the double speed rotation position detector shown in FIG.

3 is a schematic configuration explanatory diagram of a motor with a rotation position detector according to the present invention.

4 is an electrical circuit diagram for processing the output depth of the rotation position detector attached to the motor shown in FIG.

FIG. 5 is a waveform diagram showing output split values when a set of ideal resolvers constituting a rotation position detector have an axis angle of 2X and an axis angle of 3X. FIG.

FIG. 6 is a waveform diagram showing an output split value of each resolver in the case where a resolver having an axial angle of 3X is an ideal resolver among the pair of resolvers, and a resolver having an axial angle of 2X produces an output including an error.

7 and 8 are waveform diagrams showing output split values when a set of resolvers constituting a rotation position detecting device have an axial angle of 2X, an axial angle of 4X, an axial angle of 3X, and an axis of 6X, respectively.

9 and 10 are waveform diagrams showing output split values when a set of resolvers constituting the rotation position detecting device have an axial displacement angle of 4X, an axial displacement angle of 6X, and an axial displacement angle of 6X and 9X, respectively.

* Explanation of symbols for main parts of the drawings

30: motor 32: casing

34: stator 36: rotation axis

38,40: bearing 4: rotor

44: resolver 46: casing

48: rotation axis 50, 54: resolver

52,56: rotor 58,60: stator

The present invention relates to a motor to which a rotation position detector is attached. Specifically, a double speed type rotation position detector having different axial angles from each other is attached to the rotation axis of the motor, thereby enabling precise detection of the rotation angle of the rotation axis. It relates to a motor with a rotation position detector

Background Art Conventionally, a double speed type resolver has been used as a method for detecting an absolute rotation position in one revolution of a machine shaft or the like included in a robot or the like. FIG. 1 shows the configuration of an example of this type of double rotational position detecting window that combines an axial displacement angle of 1x (1x) and a NX (Nx) resolver. In this embodiment, the rotary shaft 14, which coaxially supports the resolvers 10, 12, is connected to the rotary shaft 20 of the motor 18 via a coupling 16. In this case, the resolver 10 has an axial angle of 1x (1x), and the other resolver 12 selects an axial angle of 3x (3x).

In such a configuration, FIG. 2 shows the relationship between the rotational position of the shaft 14 shown in FIG. 1 and the output split values of the resolvers 10 and 12. As shown in FIG. The horizontal axis represents the rotational position of the shaft 14 by the rotation angles θ (0 ° to 360 °), and the vertical axis represents the output divided values of the resolvers 10 and 12. In this case, the outputs of the resolvers 10 and 12 are divided into 1000 divided values from 0 to 999, respectively.

The output split of the resolver 12 with the ideal axial angle 3X increases monotonically from 0 to 999 between 0 ° and 120 ° (0th cycle), but the rotation angle θ When it reaches 120 °, it becomes 0 again. Further, the output divided value monotonously increases from zero to 999 again (first period) between the rotation angle θ between 240 ° and 240 °, and the rotation angle θ becomes zero at 240 °. Even when the rotation angle θ is between 240 ° and 360 °, the output split value is similarly monotonically increased (second period), and returns to 360 at 360 °, that is, the output split value of the resolver 12 having an ideal axial angle of 3X is the axis. It has the sawtooth waveform which makes 120 degree with respect to the rotation angle (theta) of (14).

On the other hand, the output divided value of the resolver 10 having an axial angle of 1X monotonously increases the rotation angle θ of the axis 14 from 0 ° to 360 ° from 0 to 999, and the rotation angle θ is 0 at 360 °. Return to. That is, the output splitting value of the resolver with the axial displacement angle 1X has a sawtooth waveform having a period of 360 ° with respect to the rotation angle θ of the shaft 14.

Therefore, in the above-described ideal detection device, when the output divided value of the resolver 10 having the axial angle of 1X is 0 to 332, the resolver 12 of the axial angle of 3X is in the 0th cycle. When the output divided value of the resolver 10 having the axial angle 1X is 333 to 666, the resolver 12 having the axial angle 3X is in the first period, and the output divided value of the resolver having the axial angle 1X is 667 to 999. It will be appreciated that the resolver 12 with the axial angle 3X is in the second period. Thus, the period of the resolver 12 of the axial angle 3X can be discriminated from the output division value of the resolver 10 of the axial angle 1X.

On the other hand, the output of the resolver 12 of the axial angle 3X is divided into 1000 divided values in the section of 120 degrees of the rotation angle (theta). Therefore, the absolute position can be detected by dividing the rotational position 0 ° to 360 ° of the axis 14 into 3000 divided values of 0 to 2999 by matching the period with the output divided value of the resolver 10 having the axial angle of 1X. It can be. This is the basic principle of precisely detecting the rotation angle of a rotating machine using a double speed resolver.

By the way, the phase and period of the output of the resolver change with the change of temperature. Most of the change in the output phase and the period caused by the temperature change is caused by the inequality of the electric circuit constant due to the change in the characteristics of the electric component included in the resolver. Therefore, the change in the mechanical angle of the resolver with the change in temperature is inversely proportional to the axis angle. For example, when it is 1 degree | times in the resolver of 1x of axial angle, it becomes 0.1 degrees in the resolver of 10x of axial angle. Therefore, the double-speed rotational position detecting device using a combination of conventional axial displacement angles of 1X and NX has a drawback in that there is a risk of misidentification due to temperature change.

In addition, as shown in FIG. 1, according to the prior art, the resolver 10 has an axial angle of 1X (1 times). On the other hand, as the resolver 12, one having a tonnage NX (N times) is employed. In this case, in particular, the resolver 10 having an axial angle of 1X (1x) is configured to detect the rotational position by using the eccentricity of the rotor. Therefore, when the eccentricity of the stator shaft opposite to the rotor is large, the other side of the resolver 12 There is a drawback that the top plate cannot be distinguished. That is, a particularly precise mechanical accuracy is required for the resolver 10 having an axial angle of 1 × 1 (1 times).

In addition, as shown in the prior art, a structure in which the rotation shaft 14 of the resolvers 10 and 12 and the rotation shaft 20 of the motor 18 are connected by a coupling 16 is adopted. . Therefore, when attaching this kind of resolver (10, 12) to the servo motor of the articulated robot which is widely adopted at present, and trying to control the rotational position, the existence of the coupling (16) itself is the outer dimension of the molder. The defects appear such that the coupling 16 causes a decrease in rigidity.

Accordingly, the present inventors have repeatedly studied and tested to solve the above-mentioned problems, and as a result, the axis is slightly extended from the rotational axis of the motor so that at least the axial angle is at least a predetermined number of first resolvers and the first resolver. If a second resolver with an axial angle larger than this is attached, there is no risk of misalignment due to temperature change, and it does not depend on the eccentricity of the rotor or stator constituting the resolver. A motor with a rotational position detector in which rotational position detection was achieved was found to eliminate the above problems.

Accordingly, it is an object of the present invention to provide a motor having a rotation position detector that is capable of accurately detecting the rotation position without being dependent on temperature change, suitable for miniaturization, and having excellent strength.

In order to achieve the above object, the present invention provides a rotation angle over a 360 ° from 0 ° to a rotation angle range N with a predetermined period, and outputs a first output every cycle of the rotation angle range N. The first rotation angle detector and a rotation angle ranging from 0 ° to 360 ° are divided into rotation angle ranges (N + 1) of a period in which 1 is added to the rotation angle range (N). The second rotation angle detector, which generates a second output every cycle of N + 1), is mounted directly on the axis of rotation of the motor or on an axis extending from the axis of rotation of the motor, so that the first rotation angle detector And a rotational position of the motor is detected by a first output and a second output of the second rotation angle detector.

Next, a preferred embodiment of a motor with a rotation position detector according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 3, reference numeral 30 denotes a motor, and the motor 30 has a stator 34 provided inside the casing 32 constituting it. The rotating shaft 36 is freely supported by the bearings 38 and 40 at the axial center of the casing 32, and fixes the rotor 42 corresponding to the stator 34. On the other hand, reference numeral 44 denotes a double speed resolver integrally mounted to the motor (30). That is, the casing 46 constituting the double speed resolver 44 is integrally attached to the casing 32 of the motor 30 via the annular protrusions 43 and 45 rolls, and one side of the casing 46. The part is closed from the lid member 47 via a bolt that enters the casing 32 via the annular projection 43, and the casing 46 itself is hermetically configured.

Subsequently, the rotor of the resolver which coaxially extends the rotary shaft 48 having a diameter smaller than that to the rotary shaft 36 projecting slightly from the casing 32 to the inside of the casing 46, and constitutes an axial angle N therein. The resolver 54 and the rotor 56 having one more axial angle N + 1 than the axial angle N of the resolver 50 are supported in close proximity to each other. In this case, for convenience of explanation, the axial displacement angle N of the resolver is selected to be 2, so that the axial displacement angle N + 1 of the resolver 54 is selected to be 3. In the figure, reference numeral 58 denotes a stator of the resolver 50, and reference numeral 60 denotes a stator of the resolver 54.

A calculator, a cycle discriminator, a rotation angle calculator, and the like are connected to the double speed resolver 44 of the apparatus of the present invention configured as described above (see FIG. 4). That is, the calculator 62 is connected to the output sides of the first resolver 50 and the second resolver 54. The period discriminator 64 is connected to the output side of the calculator 62, and the rotation angle calculator 66 is connected to the output side of the main discriminator 66 and the second resolver 54.

Next, the operation of the apparatus shown in FIGS. 3 and 4 will be described with reference to FIG. 5. In Fig. 5, the horizontal axis represents the rotation angle θ of the axis 36, that is, the axis 48, and the vertical axis represents the output divided value. The output value a of the first resolver 50 and the output value b of the second resolver 54 adopt a digital value divided into 1000 divided values from 0 to 999.

The split value b of the triplex angle output by the resolver 54 of the axial angle 3X represents a value ranging from 0 to 999 smoothly in proportion to the rotation angle θ in the rotation angle range between 0 and 120 ° ( Cycle 0). When the rotation angle θ of the axis 36 is 120 °, the output split value b of the resolver 54 returns to zero, and similarly monotonously increases from zero in the rotation angle range between 120 ° and 240 °. To a value up to 999 (first cycle). When the rotational angle θ is 240 °, this output divided value returns to zero again, monotonously increasing in the rotational angle range between 240 ° and 360 ° and reaching a value of 999 (second period). . That is, the triple angle divided value b output by the second resolver 54 has a period of 120 ° in the rotation angle range of 0 ° to 360 °, and monotonously increases from 0 to 999 in each period.

On the other hand, the divided value a of the double angle outputted by the first resolver 50 of the axial angle 2X has a period of 180 degrees, and monotonously increases from 0 to 999 in each period. That is, while the rotation angle θ of the axis 36 is between 0 ° and 180 °, the output split value a of the first resolver 50 monotonically increases from zero in proportion to the rotation angle θ to 999. (Cycle 0). When the rotation angle [theta] is 180 [deg.], This output divided value a returns to zero and monotonously increases back to 999 in the rotation angle range between 180 [deg.] And 360 [deg.].

(1st cycle)

The calculator 62 in which the output divided values a and b outputted from the first resolver 50 and the second resolver 54 are input, first calculates the difference c = b-a between them. This difference c can be known as -999 to +999. Next, the calculator 62 calculates the correction doubling angle division value d from this difference c. D adopts the value determined by the following conditions with respect to the rotation angle (theta). That is, it is equal to c in the rotation angle range where c is 0 or a positive value, and is equal to C + 1000 in the rotation angle range where c adopts a negative value. In other words,

d = c (c ≥ 0)

d = c +1000 (c <0)

For ease of understanding, this correction single angle division value d is monotonically increasing from 0 to 999 in proportion to the rotation angle θ in the rotation angle range between 0 ° and 360 °.

Therefore, in the rotation angle range where the rotation angle θ is between 0 and 120 °, this corrected single angle division value d adopts a value from 0 to 332, and in the rotation angle range between 120 ° and 240 °, Value, and from 667 to 999 in the rotation angle range between 240 ° and 360 °. The calculator 62 having calculated the above-described corrected single-angle division value d outputs it to the period discriminator 64.

The period discriminator 64 which inputs the correction single angle division value d from the calculator 62 first determines whether the triple angle division value b is in the first cycle. That is, when the corrected single-angle divided value d is 0 to 332, it is determined that the triple-angle divided value b is in the zeroth cycle. When the divided value d is 333 to 666, the divided value b determines that there is a second period when the divided value b is 667 to 999, that is, the output of the period discriminator 64. The determination period number f adopts the following value with respect to the input divided value d from the calculator 62.

The cycle discriminator 64 outputs the rotation angle calculator 66 at the determination cycle number f thus obtained.

The rotation angle calculator 66 having inputted the discrimination period number f from the period discriminator 64 and the triple angle division value b from the second resolver 54 is a rotation angle division given from these values by the following equation. Compute the value (9).

g＜ 3000)g = b + 1000f (only 0

g <3000)

Here, the coefficient 1000 of f on the right side is the number of divisions of the output division value b of the second resolver 54, and g adopts 3000 division values from 0 to 2999. Therefore, the output division value 9 of the rotation angle calculator 66 is divided into the number of divisions 1000 of the output division values a and b of the first and second resolvers 50 and 54 and the rotation angle 0 ° to 360 °. The detection absolute rotation position of the axis 36 in which an enemy 3000 of the number 3 of the periods of the output split value b of the second resolver 54 included divides the rotation angle range 0 ° to 360 ° of the axis 36 in an accurate manner. It will be readily understood to be a value indicating.

In the description of the above embodiment, it was assumed that both the first resolver 50 and the second resolver 54 assume no error as an ideal detector. However, in reality, the double angle resolver and the triple angle resolver cannot be limited to each having exactly 180 ° and 120 ° periods. If the error of these periods exceeds the allowable limit, the correction single angle output split value d does not increase monotonically, and the curve representing the split value d has an inflection point at rotation angles of 0 ° to 360 °. In such a case, it becomes impossible to discriminate the period of the output split value b of the second resolver 54 by the discriminator 64.

The angle curves in FIG. 6 are divided values a when the error of the period of the first resolver 50 exceeds the allowable limit in the apparatus of FIGS. 3 and 4 with the second resolver 54 as an abnormal detector. and b, c and d. The output split value b of the second resolver 54 is the same as the corresponding value b of FIG. However, the 0th period of the output split value a of the first resolver 50 exceeds the first period 120 ° to 240 ° of the output split value b of the second resolver 54 from the rotation angle 0 °. The rotation angle A。 in the second period 240 ° to 360 ° is reached, and the first period occupies a 360 ° rotation angle range from A °.

Therefore, the difference c between the dividing values b and a calculated by the calculator 62 changes as shown in FIG. 6, and the corrected single-angle dividing value d calculated therefrom does not increase monotonously, and the curve representing the dividing value d is It has an inflection point. Therefore, it is impossible to discriminate the period of the output split value b of the second resolver 54.

On the other hand, when the second resolver 54 is an ideal detector, the first period of the output split value a of the first resolver 50 is the output split value b of the second resolver 54 from a rotation angle of 0 °. Since the inflection point is reached even when 120 °, the end of the 0th cycle, is reached, the cycle determination of the output divided value b of the second resolver 54 is similarly impossible.

As can be easily understood from the above description, the tolerance between the ideal period 180 ° of the first resolver 50 and the actual period A。 is 360 ° / (2 × 3). = 60 °. That is, it is necessary to be K ° <60 °. In general, when the axial displacement angle of the second resolver 50 is N and the axial displacement angle of the second resolver 54 is N + 1, the allowable limit of the error K ° is 360 ° / {N (N + 1)}. That is, it must be K << 360 degrees / (N (N + 1)).

Considering that both the first resolver 50 and the second resolver 54 both include a periodic error K., The error K ° is actually in the embodiment of FIG. 4.

1)는안전계수)K ° <60 ° (1 / P) (P (P

1) the safety factor)

This needs to be. In addition, the periodical error K in the general case in which the axial displacement angle of the first resolver 50 is N and the axial displacement angle of the second resolver 54 is N + 1 is

K ° <[360 ° / {N (N + 1)}] (1 / P)

(Where P (P> 1) is the safety factor)

This must be done.

Next, a description will be given of the case where the first resolver 50 and the second resolver 54 each have an axial angle of nNX and n (N + 1) X.

Here, when n = 2 and N = 1, it will be easily understood that the first resolver 50 and the second resolver 54 become the axial angle 2X and the axial angle 4X, respectively. As shown in FIG. 7, the period of the 2nd resolver 54 is discriminated | determined by the 1st resolver 50 which becomes 2x of axial angle. However, although the 0th period, the 1st period, the 2nd period, and the 3rd period can be discriminated, the discrimination of the 0th period and the 2nd period or the 1st period and the 3rd period cannot be discriminated. That is, even though A and C points can be discriminated in FIG. 7, it is difficult to distinguish between A and B points.

Therefore, the plural resolver having such an axial angle is preferable because the absolute position within 1/2 rotation (180 °) of the motor 30 is detected.

In addition, when n = 3 and N = 1, the example of application when the 1st resolver 50 and the 2nd resolver 54 are 3x and 6x of axial angle, respectively is shown in FIG.

As described above, the first resolver 50 accurately determines the period of the second resolver 54 by its axial angle 3X. However, as in the application shown in FIG. 7, it is not possible to determine whether the second resolver 54 with the axial angle 6X is in the first period or in the second period. That is, in Fig. 8, it is possible to discriminate between A and C points, but it is difficult to distinguish between A and B points.

Therefore, in the double speed type resolver having such an axial angle, the absolute position within a third rotation (120 °) of the motor 30 can be preferably used.

Next, FIG. 9 shows an application example where the first resolver 50 and the second resolver 54 have an axial angle of 4X and an axial angle of 6X, respectively, when n = 2 and N = 2.

As described above, the first resolver 50 determines the cycle of the body 2 resolver 54 by its axial angle 4X. However, it is not possible to determine in which period the second resolver 54 of the axial angle 6X is located, i.e., in FIG. 9, it is possible to distinguish between A and C points but not A and B points. .

Therefore, it can be said that it is suitable for the detection of the absolute position within 1/4 rotation (90 degrees) of this kind of double speed type resolver motor 30. As shown in FIG.

Fig. 10 shows an application example in which the first resolver 50 and the second resolver 54 each have an axis of 6X and an axis of 9X, respectively, where n = 3 and N = 2.

Also in this application example, the first resolver 50 determines the period of the second resolver 54 by its axial angle 6X. However, even in this case, it is difficult to determine which cycle the second resolver 54 is in. That is, in the waveform diagram shown in FIG. 10, even if A point and C point can be distinguished by the division value indicated by the correction single angle, it is impossible to distinguish between A point and B point.

Thus, this type of double speed resolver is desirable for the detection of the absolute position within 1/6 revolution (60 °) of the motor 30. According to the present invention, although a double speed type resolver is incorporated directly in connection with the rotation axis of the motor as described above, the axial angle of each resolver is selected to be a predetermined number or more. Therefore, as the axial angle increases, the change of the machine decreases in inverse proportion, so that the error is very small in determining the period. In addition, since the position detection without using the rotor eccentricity can be performed, phase error due to the clearance of the gap between the rotor and the stator of the resolver, which has been a conventional problem, is less likely to occur, and the coupling connecting the motor and the detector becomes unnecessary. Therefore, there is an advantage that miniaturization is achieved and the improvement of rigidity is promoted.

In particular, the absolute position of the rotor constituting the motor must be detected for the synchronous motor with high speed control and positioning control. Generally, synchronous motors are widely available in 2-pole, 4-pole, and 6-pole configurations. In order to accurately detect the rotational positions of these pole motors, 1 / 2-rotation (180 °) is used for 4 poles. For 6 poles, the absolute position should be obtained within the range of 1/3 rotation (120 °). Therefore, since the rotation position detector which concerns on this invention can be attached to the pole number of motors correspondingly, the effect which can detect the rotation angle more correctly is acquired.

As mentioned above, although preferred embodiment was described about this invention, this invention is not limited to this embodiment, For example, it can use suitably for an induction motor instead of a synchronous motor as mentioned above, for example. Various improvements and design changes are possible without departing from the scope of the invention.

Claims (7)

A first rotation angle detector and 0 ° from a first rotation angle detector for producing a first output for each period of the rotation angle range N by setting the rotation angle from 0 ° to 360 ° as a rotation angle range N having a predetermined period. The rotation angle over 360 ° is divided into the rotation angle range N + 1 of the period in which 1 is added to the rotation angle range N to generate a second output for each period of the rotation angle range N + 1. A second rotation angle detector is mounted directly on the rotational axis of the motor or on an axis extending from the rotational axis of the motor, so that the first output of the first rotational angle detector and the second of the second rotational angle detector A motor with a rotation position detector, characterized in that configured to detect the rotation position of the motor by an output. The motor with a rotation position detector according to claim 1, wherein the rotation position detector is a digital value in which the first and second outputs are divided into equal numbers of division values. 2. The rotational position detector according to claim 1, wherein the first and second angle detectors are resolvers each having an axial displacement angle of N + 1, which is one greater than a predetermined number N and the predetermined number N. Motor. 4. The rotational position detector according to claim 3, wherein the rotational position detector has an integer multiple n (where n is 2 or more) and a predetermined number N of which the axial angle is 1 or more corresponding to the number of poles of the motor, respectively. A motor with a rotation position detector, characterized in that it is a resolver that is an integer number n (where n is two or more) by one greater than N (N + 1). 4. The rotational position detector according to claim 3, wherein the rotational position detector has an integer multiple n of a predetermined number N of two or more, and a number N + 1 greater than the predetermined number N, corresponding to the number of poles of the motor of the first and second angle detectors, respectively. A motor with a rotation position detector, characterized in that it is a resolver with an integer multiple n. The motor with a rotation position detector roll according to claim 1, wherein the motor is constituted by a synchronous motor. The motor with a rotation position detector according to claim 1, wherein the motor is composed of an induction motor.

Images