JPWO2019220516A1 - Actuator and torque sensor unit - Google Patents

Abstract

The torque measuring unit (2) of the actuator (1) is arranged between the actuator fixing portion (5) and the mounting flange (7) facing each other from the direction along the actuator center axis (1a). In the torque measuring unit (2), the sensor piece (4) to which the strain gauges (3a and 3b) are attached is bridged in the direction along the actuator center axis (1a). Since each component for torque detection is laid out in the axial direction instead of the radial direction, the torque sensor can be attached to the actuator without requiring a large amount of installation space in the radial direction. Since the sensor piece (4) is manufactured as a separate part from the mounting flange (7), the torque measuring unit (2) can be easily manufactured.

Description

The present invention relates to an actuator provided with a torque sensor that detects the torque generated by the rotary actuator, and a torque sensor unit that is attached to and used by the rotary actuator.

SIMEX30Nm (manufacturer: SENSODIVE GmbH, URL: https://www.sensodrive.de/EN/products/torque-sensors/SIMEX30Nm.php) is used as a torque sensor for measuring the torque generated by the rotary actuator. Are known. In this actuator-integrated torque sensor, a ring-shaped inner flange and a ring-shaped outer flange are concentrically arranged, and a plurality of ribs extending in the radial direction are integrally formed between them. A strain gauge is attached to the rib part to form a torque measuring part. The inner flange is fixed to the reducer of the actuator, and the outer flange is the actuator fixing portion. Further, Patent Document 1 describes a torque sensor having a structure in which a strain gauge is attached to a strain generating portion that radially connects between an inner rotating body and an outer rotating body arranged concentrically.

JP-A-2017-203645

In the torque sensor having this configuration, ribs for torque measurement are integrally formed between the inner flange and the outer flange arranged concentrically, and the radial dimension is large. Therefore, it is not suitable when the installation space cannot be secured outside in the radial direction of the actuator. Further, since it is necessary to attach the strain gauge to the thin ribs located in the narrow space between the inner flange and the outer flange, it may be difficult to attach the strain gauge.

In view of these points, an object of the present invention is to provide an actuator provided with a torque sensor that does not require a large installation space in the radial direction, and a torque sensor unit.

Another object of the present invention is to provide an actuator and a torque sensor unit provided with a torque sensor which does not require a large installation space in the radial direction and is easy to assemble.

In order to solve the above problems, the actuator provided with the torque sensor for detecting the torque output from the actuator output rotating member according to the present invention is provided.
The actuator fixing part provided on the actuator fixing side member and
It is provided on the actuator fixing side member, and is provided with a mounting flange facing the actuator fixing portion from a direction along the actuator central axis.
The torque measuring unit of the torque sensor
A sensor piece bridged between the actuator fixing portion and the mounting flange in a direction along the actuator center axis, and a sensor piece.
It is attached to the sensor piece and includes a strain detecting element for detecting the strain generated in the sensor piece.

In the actuator of the present invention, each component for torque measurement (actuator fixing portion, mounting flange, sensor piece to which a strain detection element is mounted) is laid out not in the radial direction but in the axial direction. This makes it possible to detect the torque of the actuator without requiring a large amount of installation space in the radial direction. Therefore, it is possible to realize an actuator equipped with a torque sensor that is compact in the radial direction.

In the present invention, the sensor piece is manufactured as a separate part from the actuator fixing portion and the mounting flange, and is connected and fixed to each of the actuator fixing portion and the mounting flange by screwing, adhesion, or the like.

Compared with the case where the sensor piece is integrally formed with the actuator fixing portion and the mounting flange, the work such as attaching the strain detection element to the sensor piece becomes easier. Further, the replacement work of the torque measuring unit including the strain detection element and the sensor piece becomes easy. It is also easy to provide a plurality of mounting positions of the torque measuring unit and change the mounting points of the torque measuring unit or the number of mounted torque measuring units as needed.

In the present invention, a plurality of torque measuring units are arranged at predetermined angular intervals on the same circle centered on the actuator center axis. For example, they are arranged in two places at an angle interval of 180 degrees.

Further, the sensor piece is provided with a first element mounting surface facing one side in the circumferential direction centered on the actuator center axis and a second element mounting surface facing the other side, and serves as a strain detecting element. A first strain gauge and a second strain gauge are attached to the 1-element mounting surface and the 2nd element mounting surface, respectively.

For example, a total of four strain gauges attached to two sensor pieces arranged at 180 degree intervals are connected so as to form a Wheatstone bridge circuit, and changes in resistance are converted into changes in voltage for output. To do. As a result, a detection signal corresponding to the moment generated between the actuator fixing portion and the mounting flange can be obtained.

Next, according to the present invention, the torque sensor unit for detecting the torque output from the output rotating member of the actuator to the driven member is
Actuator fixing part and
The mounting flange facing the actuator fixing portion from the direction along the central axis of the unit,
It has a torque measurement unit and
The torque measurement unit
A sensor piece bridged between the actuator fixing portion and the mounting flange in a direction along the central axis of the unit, and
It is characterized in that it is attached to the sensor piece and includes a strain detecting element for detecting the strain generated in the sensor piece.

Each component of the torque sensor unit of the present invention is laid out in the axial direction instead of the radial direction. It can be attached to the actuator without requiring a lot of installation space in the radial direction.

The sensor piece is manufactured as a separate part from the actuator fixing portion and the mounting flange, and is connected and fixed to each of the actuator fixing portion and the mounting flange by screwing, adhesion, or the like. Compared with the case where the sensor piece is integrally formed with the actuator fixing portion and the mounting flange, the torque measuring portion can be easily manufactured.

It is a perspective view which shows the rotary type actuator provided with the torque sensor to which this invention is applied. It is a side view of the actuator shown in FIG. It is a top view of the actuator shown in FIG. It is a perspective view which shows the sensor piece of the actuator shown in FIG. It is a front view of the sensor piece shown in FIG. 3A. It is a perspective view which shows the torque sensor unit to which this invention is applied.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

FIG. 1 is a perspective view showing a rotary actuator provided with a torque sensor to which the present invention is applied, FIG. 2A is a side view of the actuator, and FIG. 2B is a plan view of the actuator. Explaining with reference to these figures, the actuator 1 is provided with a torque sensor for measuring the torque generated or received by the actuator 1. The torque measuring unit 2 of the torque sensor includes first and second strain gauges 3a and 3b, and a sensor piece 4 to which these gauges are attached. The sensor piece 4 is manufactured as a single component, and is mounted between the actuator fixing portion 5 provided on the actuator 1 and the mounting flange 7 mounted on the mounting object 6 shown by the imaginary line. By detecting the deformation of the sensor piece 4 with the first and second strain gauges 3a and 3b, the torque generated by the actuator 1 (the moment received by the actuator fixing portion 5) can be measured.

The sensor piece 4 is bridged in the direction along the actuator center axis 1a between the actuator fixing portion 5 and the mounting flange 7 facing each other from the direction along the actuator center axis 1a. As a result, the actuator 1 provided with the torque sensor can be compactly configured in the radial direction. Further, by making the sensor piece 4 a single component, the torque measuring unit 2 can be easily manufactured.

The configuration of each part will be described in more detail. The actuator 1 is a geared motor including a motor 11 and a speed reducer 12 coaxially connected. The speed reducer 12 is, for example, a planetary speed reducer, but the speed reducer 12 may be another type of speed reducer. The motor 11 includes a motor case 13 having a substantially rectangular contour, and an actuator fixing portion 5 is formed at a front end portion on the output side of the motor case 13. The actuator fixing portion 5 of this example is an annular speed reducer fixing portion that extends outward from the front end portion of the motor case 13. The rear end portion of the speed reducer case 14 of the speed reducer 12 is coaxially connected and fixed to the front surface of the actuator fixing portion 5 which is the speed reducer fixing portion. An output rotating member 15 which is a speed reducer output shaft is exposed on the front end surface of the speed reducer case 14. Further, an annular mounting flange 7 extending outward is formed at the front end portion of the speed reducer case 14.

The actuator fixing portion 5 and the mounting flange 7 face each other at regular intervals from the direction along the actuator center axis 1a. A torque measuring unit 2 composed of a sensor piece 4 to which a strain gauge 3 is attached is arranged between the inner end surface 16 of the actuator fixing portion 5 facing each other and the inner end surface 17 of the mounting flange 7. In this example, the torque measuring units 2 are arranged at two locations on the same circle centered on the actuator center axis 1a at an angle interval of 180 degrees. In each torque measuring unit 2, two first and second strain gauges 3a and 3b are attached to each of the sensor pieces 4.

The sensor piece 4 of this example has a rectangular frame shape. The sensor piece 4 is bridged between the inner end faces 16 and 17 in a direction along the actuator center axis 1a. Further, the sensor piece 4 is fixed to the actuator fixing portion 5 by the screw 18a, and is fixed to the mounting flange 7 by the screw 18b.

FIG. 3A is a perspective view showing an example of the sensor piece 4, and FIG. 3B is a front view thereof. The sensor piece 4 of this example is a rectangular frame-shaped piece having a constant thickness, and a rectangular hollowed-out portion 45 having rounded corners is formed at the center of a rectangular parallelepiped. The outer surfaces of the left and right side frame portions 41 and 42 of the sensor piece 4 are the first element mounting surface 41a and the second element mounting surface 42a, respectively.

Screw holes 43a and 44a are formed in the centers of the front and rear end frame portions 43 and 44 of the sensor piece 4, and the screws 18a and 18b are screwed and fixed in these holes. The shape of the sensor piece 4 may be another shape. Further, the hollow shape is not limited to a quadrangle with rounded corners, and can be hollowed into, for example, a dumbbell shape.

In each torque measuring unit 2, the sensor piece 4 is arranged so that its side frame portions 41 and 42 face in the circumferential direction, as can be seen from FIGS. 1, 2A and 2B. A first strain gauge 3a is attached to the first element mounting surface 41a, which is the outer surface of the side frame portion 41. Similarly, the second strain gauge 3b is attached to the second element mounting surface 42a, which is the outer surface of the side frame portion 41. The signals from the first and second strain gauges 3a and 3b are taken into a predetermined signal processing unit via wiring (not shown).

In this example, the torque measuring units 2 (two sensor pieces 4) are arranged to face each other at two places. The number of torque measuring units 2 (sensor pieces 4) is not limited to two. Torque measuring units 2 (sensor pieces 4) can be arranged at three or more locations at predetermined angular intervals. For example, four torque measuring units (sensor pieces 4) can be arranged at equal angular intervals. Further, the number of sensor pieces 4 and the number of strain gauges 3a and 3b are not directly related to each other. The number of sensor pieces and the number of strain gauges can be set so that the Wheatstone bridge can be properly configured to detect torque.

In the actuator 1, the actuator fixing portion 5 which is the speed reducer fixing portion is fixed to a fixed side member (not shown). The output rotating member 15 is connected to a driven member on the side of the mounting object 6 shown by the imaginary line in FIG. 1, for example, a robot arm (not shown). For example, when the actuator 1 outputs a torque while the robot arm is fixed to something, the torque generated by the output rotating member 15 is applied to the actuator 1 as an anti-moment from the side of the actuator fixing portion 5. The anti-moment deforms the sensor piece 4 fixed to the actuator 1. The first and second strain gauges 3 attached to the sensor piece 4 expand and contract according to the deformation of the sensor piece 4, and their resistance values change.

Focusing on one sensor piece 4, when a moment is applied to the actuator 1, one side frame portion of the sensor piece 4, for example, the first element mounting surface 41a of the side frame portion 41 is stretched. The second element mounting surface 42a of the other side frame portion 42 shrinks. The first and second strain gauges 3a and 3b attached to the first and second element mounting surfaces 41a and 42a also expand and contract in the same manner, and their resistance values change. The same applies to the other sensor piece 4. By forming a Wheatstone bridge with four strain gauges, it is possible to electrically extract the resistance change and detect the moment applied to the actuator 1.

(Torque sensor unit)
Next, the torque sensor according to the present invention can be configured as a unit and attached to an actuator or another speed reducer. FIG. 4 is a perspective view showing an example of the torque sensor unit. The torque sensor unit 50 faces the actuator fixing portion 55 and the actuator fixing portion 55 from the direction along the unit central axis 50a in order to detect the torque output from the output rotating member of the actuator (not shown) to the driven member. A torque measuring unit 52 is provided between the mounting flange 57 and the actuator fixing portion 55 and the mounting flange 57 in a direction along the unit central axis 50a. The torque measuring unit 52 includes a sensor piece 54 and strain gauges 53a and 53b attached to the sensor piece 54. The sensor piece 54 is fixed to the inner end surface 66 of the mounting flange 57 by screws 68b, and is fixed to the inner end surface 67 of the mounting flange 57 by screws 68a.

The actuator fixing portion 55 is, for example, a portion fixed to the actuator fixing portion 5 of the actuator 1, and the mounting flange 57 is a portion fixed to the mounting flange 7 of the actuator 1. Further, the sensor piece 54 corresponds to the above-mentioned sensor piece 4, and the strain gauges 53a and 53b correspond to the above-mentioned strain gauges 3a and 3b. Since these parts can be configured in the same manner as in the above example, the description thereof will be omitted.

Claims (9)

Actuator output An actuator equipped with a torque sensor that detects the torque output from the rotating member to the driven member.
The actuator fixing part provided on the actuator fixing side member and
It is provided on the actuator fixing side member, and is provided with a mounting flange facing the actuator fixing portion from a direction along the actuator central axis.
The torque measuring unit of the torque sensor
A sensor piece bridged between the actuator fixing portion and the mounting flange in a direction along the actuator center axis, and a sensor piece.
An actuator attached to the sensor piece and provided with a strain detecting element for detecting the strain generated in the sensor piece. In claim 1,
The sensor piece to which the strain detection element is mounted is a separate component from the actuator fixing portion and the mounting flange.
The sensor piece is an actuator that is connected and fixed to each of the actuator fixing portion and the mounting flange. In claim 1,
A plurality of the torque measuring units are arranged at predetermined angular intervals on the same circle centered on the actuator center axis. In claim 1,
The sensor piece includes a first element mounting surface facing one side in the circumferential direction about the actuator center axis and a second element mounting surface facing the other side.
The strain detecting element is an actuator which is a first strain gauge and a second strain gauge attached to the first element mounting surface and the second element mounting surface, respectively. In claim 1,
With the motor
An annular speed reducer mounting flange, which is an actuator fixing portion, formed at a front end portion on the output side of the motor case of the motor,
A speed reducer mounted coaxially on the speed reducer mounting flange and
The actuator output rotating member exposed on the front end surface on the output side of the reducer case of the reducer,
An actuator including an annular mounting flange formed on the front end of the speed reducer case. A torque sensor unit that detects the torque output from the output rotating member of the actuator to the driven member.
Actuator fixing part and
The mounting flange facing the actuator fixing portion from the direction along the central axis of the unit,
It has a torque measurement unit and
The torque measuring unit
A sensor piece bridged between the actuator fixing portion and the mounting flange in a direction along the central axis of the unit, and
A torque sensor unit that is attached to the sensor piece and includes a strain detecting element that detects the strain generated in the sensor piece. In claim 6,
The sensor piece is a separate component from the actuator fixing portion and the mounting flange.
The sensor piece is a torque sensor unit that is connected and fixed to each of the actuator fixing portion and the mounting flange. In claim 6,
The sensor piece to which the strain detecting element is attached is a torque sensor unit in which a plurality of the sensor pieces are arranged at predetermined angular intervals on the same circle centered on the center axis of the unit. In claim 6,
The sensor piece includes a first element mounting surface facing one side in the circumferential direction about the center axis of the unit and a second element mounting surface facing the other side.
The strain detection element is a torque sensor unit which is a first strain gauge and a second strain gauge attached to the first element mounting surface and the second element mounting surface, respectively.

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