JPH1189176A - Reduction mechanism-integrated servo actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction mechanism-integrated servo actuator which does not restrict the degrees of freedom of an actuator shape and which is small and thin. SOLUTION: An actuator is provided with a rotation drive part 2, which is composed of a shaft 23 having a rotor 24 on the outer circumference and of a stator 21 having a stator winding 22 installed to face the rotor 24, a reduction mechanism 3 which is connected to the load side of the shaft 23 at the rotation drive part 2 and which has a plurality of gears for reducing rotation from the rotation drive part 2 to be transmitted identically and a servo sensor part 4 which detects the position and the speed of the rotation drive part 2. In this case, the servo sensor part 4 is constituted of a magnetization part 43 which is formed on the surface of an input gear 33 at the reduction mechanism 3 to face the load side of the shaft 23 at the rotation drive part 2 and which has at least one set of magnetic poles, and a magnetic-field detection means 41 such as Hall element or the like installed via a gap in a position facing the magnetization part 43 at the input gear 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and thin servo actuator integrated with a speed reduction mechanism used in a minute space.

[0002]

2. Description of the Related Art FIG. 4 is a schematic view of a conventional servo actuator integrated with a speed reduction mechanism. Reference numeral 1 denotes a servo actuator integrated with a deceleration mechanism, 2 denotes a rotation drive unit of the servo actuator 1, 21 denotes a stator provided in the rotation drive unit 2 and has a plurality of slots therein, and 22 denotes a stator wound around the stator 21. A child winding, 23 is a rotating shaft provided inside the stator 21;
24 is a rotor fitted to the outer periphery of the rotating shaft 23, 25a,
25b is a bearing for supporting the rotating shaft 23 between the brackets 26a and 26b, 27 is a frame, 3 is a reduction mechanism connected to the load side of the rotating shaft 23, 31 is an output shaft of the reduction mechanism 3, 32 is a bearing, Reference numeral 33 denotes an input gear having a disk shape and teeth formed on one side, reference numeral 34 denotes an intermediate gear meshing with the input gear 33,
Is an output gear that meshes with the intermediate gear 34, 36 is a frame,
Reference numeral 37 denotes a bracket, and reference numeral 5 denotes a servo sensor unit connected in series to the non-load side of the rotation shaft 2 of the rotation drive unit 2. In such a configuration, the rotating shaft 23 is connected to a reduction mechanism composed of an input gear 33 provided in series on the load side thereof and a planetary gear composed of an intermediate gear 34 and an output gear 35, and is connected to the rotating shaft 23.
1 is decelerated and transmitted from the output shaft 31. Further, the position and speed of the rotor 24 are detected by the servo sensor unit 5. In general, an optical encoder or an electromagnetic rotation sensor is used for a servo sensor unit that constitutes a position and speed detector of a servo actuator (for example, Japanese Patent Application Laid-Open No. Sho 59-61702).

[0003]

Conventionally, a servo actuator integrated with a speed reduction mechanism has such a configuration because a rotary drive unit, a speed reduction mechanism unit, and a servo sensor unit, which are its components, are individually and serially arranged. Then, when the size is reduced, there is a problem that the length becomes longer in the axial direction, and the degree of freedom of the shape of the servo actuator itself is restricted. Therefore, the present invention provides a degree of freedom in the shape of the actuator by providing a magnetized structure having a position / speed detection function in a part of the reduction mechanism gear and configuring a servo sensor by combining the reduction mechanism and the magnetic field detection means. It is an object of the present invention to provide a small and thin servomotor with a built-in deceleration mechanism without restraining the servo actuator.

[0004]

In order to solve the above problems, the present invention has the following arrangement. (1) a rotation drive unit including a rotation shaft having a rotor on the outer periphery and a stator having a stator winding provided to face the rotor, and a rotation drive unit connected to a load side of the rotation shaft of the rotation drive unit; A speed reduction mechanism having a plurality of gears for transmitting the rotation from the rotation drive unit in a decelerated manner, and a servo sensor unit for detecting the position and speed of the rotation drive unit; and In the servo actuator integrated with a speed reduction mechanism that controls the position and speed of the rotation drive unit by a signal, the servo sensor unit is disposed on a surface of an input gear of the speed reduction mechanism facing a load side of a rotation shaft of the rotation drive unit. And a magnetic field detecting means provided through a gap at a position facing the magnetized portion of the input gear, according to the rotation of the speed reduction mechanism. Before the changing signal The magnetic field is detected by the magnetic field detecting means. (2) The magnetic field detecting means is a Hall element. (3) The magnetic field detecting means is a magnetoresistive element. (4) The magnetic field detecting means is a flux gate. By the above-mentioned means, the servo actuator integrated with the speed reduction mechanism has a magnetized structure having a position / speed detection function in a part of the input gear of the speed reduction mechanism, and performs servo control by combining the input gear of the speed reduction mechanism with the magnetic field detection means. The sensor configuration eliminates the need for slits and gears for detection, which were required in conventional position / speed detectors, and allows the actuator to be smaller and thinner without restricting the degree of freedom of the actuator shape. .

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a servo actuator integrated with a speed reduction mechanism showing an embodiment of the present invention. FIG.
FIGS. 4A and 4B illustrate a servo sensor unit, FIG. 4A is a plan view of a disk having magnetic field detecting means, and FIG. 4B is a plan view of an input gear having a pair of magnetic poles. The part and the magnetic field detection part are shown in a form with a spread. The same components as those in the conventional example are denoted by the same reference numerals, the description thereof will be omitted, and different components will be described. In FIG. 1, the point different from the conventional example is that the servo sensor unit which was conventionally on the non-load side of the rotation drive unit 2 is removed, and the position / speed detection is performed by using a part of the input gear 33 of the speed reduction mechanism 3. A set of magnetic poles having a function forms a magnetized portion 43 magnetized, and a disk 42 having a magnetic field detecting means 41 is provided on a bracket 26a on the load side at a position facing the magnetized portion 43. . FIG.
, 41a and 41b are examples in which a Hall element is used as a magnetic field detecting means, respectively, and the positional relationship between the two is such that the magnetic pole pitch of the input gear 33 in which a set of magnetic poles is magnetized is λ, and n is a natural number , (N + 1/4) λ on the same circumference. With such a configuration, the output from the rotation drive unit 2 is transmitted from the rotation shaft 23 to the input gear 33 and the intermediate gear 34 of the reduction mechanism 3. The input gear 33 of the speed reduction mechanism rotates in the same manner as the rotating shaft 23, and includes a magnetized portion 43 provided on the input gear 33 and a magnetic field detecting means 4 such as a Hall element provided on a disk 42 fixed to the bracket 26a.
By calculating the change of the voltage signal obtained by 1a, 41b, the position and rotation speed of the rotating shaft 23 can be detected. Therefore, the magnetic field detecting means 41a, 41b
The position can be detected with a resolution of 1/4 of the magnetic pole pitch on the basis of the voltage signal obtained from the above, and speed information can be obtained by differentiating the position signal. As another embodiment, FIG. 3 shows a case where the magnetized portion of the input gear is multipolar magnetized. (a) is a plan view of a disk having magnetic field detecting means,
(b) is a plan view of the multipolar-magnetized input gear, in which the magnetized portion and the magnetic field detection portion are shown with a spread. Hall elements are arranged on the same circumference via a distance of (n + 1/4) λ, where λ is the magnetic pole pitch and n is a natural number, as in the case of the input gear in which a pair of magnetic poles are magnetized. Have been. In such a configuration, the same operation and effect as those of the input gear in which one set of magnetic poles is magnetized are provided, and thus the description thereof is omitted. The same effect can be obtained in a configuration in which the magnetized portion of the input gear of the reduction mechanism is magnetized on the tooth surface instead of the surface, and the change in the magnetic field is detected at the tooth tip. Further, the magnetic field detecting means includes:
Instead of the Hall element, a magnetoresistive element or a flux gate may be used.

[0006]

As described above, according to the present invention, a part of the input gear of the reduction mechanism is provided with a magnetized structure having a position / speed detection function, and the input gear of the reduction mechanism and the magnetic field detecting means are provided. By combining the servo sensors, the slits and gears for detection, which were necessary in the conventional position and speed detection devices, are not required, and the size and thickness of the actuator can be reduced without restricting the degree of freedom of the actuator shape. There is an effect of obtaining a servo actuator integrated with a reduction mechanism.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a speed reduction mechanism integrated servo actuator showing an embodiment of the present invention.

FIGS. 2A and 2B are explanatory diagrams showing a configuration of a servo sensor unit according to an embodiment of the present invention, wherein FIG. 2A is a plan view of a disk having magnetic field detecting means, and FIG. It is a top view of a gear.

3A and 3B are explanatory views showing the configuration of a servo sensor unit according to another embodiment, in which FIG. 3A is a plan view of a disk having a magnetic field detecting means, and FIG. 3B is a plan view of a multipolar magnetized input gear; It is.

FIG. 4 is a side sectional view showing a conventional servo actuator integrated with a speed reduction mechanism.

[Explanation of symbols]

 1: Servo actuator integrated with reduction mechanism 2: Rotation drive unit 21: Stator 22: Stator winding 23: Rotating shaft 24: Rotor 3: Reduction mechanism 33: Input gear 34: Intermediate gear 35: Output gear 4: Servo Sensor part 41: magnetic field detecting means 41a, 41b: Hall element 42: Disk 43: Magnetized part

Claims (4)

[Claims] 1. A rotary drive unit comprising a rotary shaft having a rotor on the outer periphery and a stator having a stator winding provided opposite to the rotor, and connected to a load side of the rotary shaft of the rotary drive unit. A servo mechanism that detects a position and a speed of the rotary drive unit, and a speed reduction mechanism having a plurality of gears that reduce the rotation from the rotary drive unit and transmit the same speed. In the servo actuator integrated with a speed reduction mechanism that controls the position and speed of the rotation drive unit based on a signal from the control unit, the servo sensor unit includes an input gear of the speed reduction mechanism facing a load side of a rotation shaft of the rotation drive unit. And a magnetic field detecting means provided through a gap at a position facing the magnetized portion of the input gear, and a magnetic field detecting means provided at a position opposed to the magnetized portion of the input gear. Change according to A servo signal integrated with a speed reduction mechanism, wherein the signal is detected by the magnetic field detection means. 2. The servo actuator according to claim 1, wherein said magnetic field detecting means is a Hall element. 3. The servo actuator according to claim 1, wherein said magnetic field detecting means is a magnetoresistive element. 4. The servo actuator according to claim 1, wherein said magnetic field detecting means is a flux gate.