JP7305364B2 - Multi-axis sensor - Google Patents

Description

The present invention relates to a multiaxial sensor that detects forces in multiaxial directions.

In general, it is known to provide a multiaxial sensor with a stopper structure in order to protect it from damage and breakage due to application of an excessive load exceeding the rating (see Patent Document 1).

JP-A-10-293070

However, in the case of a multi-axis sensor, when trying to protect external forces applied in multiple directions with a single stopper structure, highly accurate processing technology for each part or complicated adjustment after assembly is often required. On the other hand, if a separate stopper structure is provided for external forces in each axial direction, the number of parts increases, the size of the sensor as a whole increases, and the manufacturing cost increases.

An object of embodiments of the present invention is to provide a multiaxial sensor that can more easily provide a stopper structure for protection against external forces in multiaxial directions.

A multiaxial sensor according to the aspect of the present invention includes a flat plate-shaped first region located in a central portion, and an elastic body formed integrally with the first region, and the elastic body is formed integrally with the first region. a second region located on the outer peripheral side; multiaxial force detection means for detecting forces in multiaxial directions based on relative displacement amounts between the first region and the second region; the first tapered surface and the second tapered surface facing each other on both sides in the circumferential direction, the two first tapered surfaces of the first tapered surface being separated from each other; first stopper means that functions as a stopper by contacting the opposing first tapered surfaces; The elastic body has a shape that can be wire-cut .

According to the embodiments of the present invention, it is possible to provide a multiaxial sensor in which a stopper structure for protecting against external forces in multiaxial directions can be more easily provided.

1 is a perspective view of the configuration of a multiaxial sensor according to an embodiment of the present invention, viewed obliquely from above; FIG. FIG. 2 is a cross-sectional view taken along line AA' of the stopper structure portion of FIG. 1 according to the embodiment; FIG. 2 is a cross-sectional view taken along line BB′ of the stopper structure portion SP of FIG. 1 according to the embodiment; FIG. 5 is an image diagram showing the operation of the stopper structure portion according to the embodiment with respect to force in the Z-axis direction. 4A and 4B are image diagrams showing the operation of the stopper structure portion according to the embodiment with respect to force in the X-axis or Y-axis direction. 4A and 4B are image diagrams showing the motion of the stopper structure portion according to the embodiment with respect to the X-axis or Y-axis moment. FIG. 4 is a flowchart showing a method for manufacturing a multiaxial sensor according to the embodiment; FIG. 4 is a simplified diagram simply showing a gap in a stopper structure portion according to the embodiment; FIG. 4 is a perspective view showing a modified configuration of the multiaxial sensor according to the embodiment;

(embodiment)
FIG. 1 is a perspective view of the configuration of a multiaxial sensor 10 according to an embodiment of the present invention, viewed obliquely from above.
The multiaxial sensor 10 has a thick flat plate shape. The outer shape of the multiaxial sensor 10 is a flange shape that has the same shape at every predetermined angle from the center. The brim-shaped surface is circular, polygonal, or the like. For example, the multi-axis sensor 10 is mounted on a robot or the like.

The multi-axis sensor 10 detects 6 axes of X-axis direction force Fx, Y-axis direction force Fy, Z-axis direction force Fz, X-axis moment Mx, Y-axis moment My, and Z-axis moment Mz. . Here, the X, Y and Z axes are orthogonal to each other, and the XY plane formed by the X and Y axes is parallel to the planar portion of the multiaxial sensor 10 . The Z axis is perpendicular to the XY plane or planar portion of the multi-axis sensor 10 .

The multiaxial sensor 10 includes a first area section 1 , a second area section 2 , and a plurality of strain bodies 3 . The multiaxial sensor 10 may include a detection circuit, a base, a cover, various wirings, or attachment parts for attaching the multiaxial sensor 10 to a mounting location, for detecting displacements in multiaxial directions, if necessary. shall be prepared.

The first region portion 1 and the second region portion 2 are elastic bodies integrally formed of a material such as metal. The first area portion 1 is formed in an annular shape with a hole in the center, and is positioned at the central portion (central portion) of the multiaxial sensor 10 . The second region portion 2 is positioned so as to overlap the center of the first region portion 1 and cover the outer periphery of the first region portion 1 . The elastic body of the multiaxial sensor 10 may have any shape as long as the second region 2 is located on the outer peripheral side of at least a part of the first region 1 . For example, a portion of the first region portion 1 may be positioned between the second region portions 2 or on the outer peripheral side.

The first region portion 1 is attached to the movable portion and the second region portion 2 is attached to the fixed portion. The multiaxial sensor 10 detects forces in multiaxial (six-axis) directions based on relative displacement amounts between the first region 1 and the second region 2 . Note that the first region portion 1 may be attached to the fixed portion, and the second region portion 2 may be attached to the movable portion. For example, when the multi-axis sensor 10 is provided at a joint of a robot, one of the first area part 1 and the second area part 2 is attached to the hand or arm of the robot, and the other rotates in the Z-axis direction. It is attached to a motor or speed reducer that serves as a power source that generates torque on a shaft.

A plurality of strain generating bodies 3 are arranged so that the longitudinal direction extends in the radial direction at equal intervals from the center, and are provided so as to connect (straddle) the first region portion 1 and the second region portion 2. be done. Note that the strain-generating body 3 may be provided in any manner as long as it is provided so as to apply force due to relative displacement between the first region portion 1 and the second region portion 2 . For example, the strain-generating body 3 may be provided so as to be attached to a beam connecting the first region 1 and the second region 2 . Although any number of strain-generating bodies 3 may be provided as long as they are two or more, three or more are required to function as a force sensor that detects six axes. Here, the configuration of the multiaxial sensor 10 in which three strain-generating bodies 3 are provided at intervals of 120 degrees from the center will be mainly described.

The strain-generating body 3 is configured by attaching a plurality of strain gauges that serve as sensors for detecting strain to a rectangular plate-shaped member that serves as a base. The strain gauge is configured to produce an electrical displacement when deformed. As long as at least one strain gauge is provided for one strain-generating body 3, any number of strain gauges may be provided and may be arranged in any direction. Any strain gauge may be used as long as it produces an electrically detectable displacement. For example, the strain gauge may change electrical resistance or generate voltage according to the amount of deformation. By detecting these electrical displacements, the multiaxial sensor 10 performs calculations so as to extract only the force in the axial direction to be measured, thereby measuring the force on each axis.

The mounting hole H1 is a screw hole through which a bolt is inserted to mount the multiaxial sensor 10 on a fixed side such as a base. The mounting hole H2 is a screw hole for passing a bolt to mount the multiaxial sensor 10 on the movable side of a movable part or the like. Other holes are provided by removing light or the like for reasons such as weight reduction or adjusting the detection sensitivity of the sensor.

Next, the stopper structure portion SP will be described.
FIG. 2 is a cross-sectional view of the stopper structure portion SP of FIG. 1 according to the present embodiment, taken along line AA' (X-axis direction, radial direction). FIG. 3 is a cross-sectional view of the stopper structure portion SP of FIG. 1 according to the present embodiment, taken along line BB′ (Y-axis direction, circumferential direction).

The stopper structure portion SP is composed of the first structure portion 11 of the first region portion 1 and the second structure portion 21 of the second region portion 2 . The surfaces of the first structural portion 11 and the second structural portion 21 facing each other are tapered surfaces that are inclined so as to merge with each other. A gap is provided between the two tapered surfaces facing each other. The complete contact of this gap serves as a stopper.

FIG. 1 shows an example in which three stopper structure portions SP are arranged between the strain-generating bodies 3 in the circumferential direction at equal angular (120 degree) intervals from the center, but how many stopper structure portions SP are provided? can be, and can be arranged in any way. Here, one stopper structure portion SP will be described with reference to the X-, Y-, and Z-axes, but the same applies to other stopper structure portions SP.

A cut portion CL is provided at a corner where the first structural portion 11 and the second structural portion 21 face each other. By providing the cut portion CL, the corners of the first structural portion 11 and the second structural portion 21 come into contact with each other before the tapered surfaces of the first structural portion 11 and the second structural portion 21 come into contact with each other. Unintended operation of the stopper can be avoided.

As shown in FIGS. 2 and 3, the gap between the tapered surfaces is sloped.
As can be seen from the X-axis direction cross-section of the stopper structure portion SP shown in FIG. 2, the inclination of the gap creates a gap in the X-axis direction and the Z-axis direction. Therefore, this gap serves as a stopper in the X-axis direction and the Z-axis direction.

As can be seen from the cross section of the stopper structure portion SP in the Y-axis direction shown in FIG. 3, the gaps are formed in the Y-axis direction and the Z-axis direction due to the inclination of the gap. Therefore, this gap serves as a stopper in the Y-axis direction and the Z-axis direction.
When a force Fz in the Z-axis direction is applied to the first region 1, the tapered surface of the second structural portion 21 acts like a receiving plate and receives the tapered surface of the first structural portion 11, as shown in FIG. This serves as a stopper against the force Fz in the Z-axis direction.

When a force Fx in the X-axis direction or a force Fy in the Y-axis direction is applied to the first region 1, the tapered surface of the first structural portion 11 is received by the tapered surface of the second structural portion 21, as shown in FIG. This serves as a stopper against the force Fx in the X-axis direction or the force Fy in the Y-axis direction.
When the X-axis moment Mx or the Y-axis moment My is applied to the first region portion 1, the tapered surface of the first structural portion 11 contacts the tapered surface of the second structural portion 21 at least at one point, as shown in FIG. . This serves as a stopper against the X-axis moment Mx or the Y-axis moment My.

2 and the tapered surfaces facing each other in the radial direction (Y-axis direction) shown in FIG. may For example, the tapered surfaces opposed in the circumferential direction mainly function as stoppers against the Z-axis direction force Fz, the Z-axis moment Mz, the X-axis moment Mx, and the Y-axis moment My, and the tapered surfaces opposed in the radial direction , Z-axis direction force Fz.

FIG. 7 is a flowchart showing a method for manufacturing the multiaxial sensor 10 according to this embodiment. FIG. 8 is a simplified diagram simply showing the gap of the stopper structure portion SP according to this embodiment.
Next, a method of determining the gap of the stopper structure portion SP in the manufacturing process of the multiaxial sensor 10 will be described. It should be noted that the manufacturing method of the multi-axis sensor 10 described here is an example, and the manufacturing does not necessarily have to be performed in this way.

Specifications of the multi-axis sensor 10 are created based on the purpose or application (step S101). Based on the created specifications, the elastic body including the stopper structure portion SP is designed (step S102).
Six axial forces Fx, Fy, Fz, Mx, My, and Mz are applied to the designed elastic body (step S103). Here, the application of force may be performed by computer simulation, may be performed on an elastic body manufactured for trial production, or may be performed by other methods. Moreover, the force to be applied is not limited to the rated value, and may be any value as long as it does not exceed the maximum force that is applied during normal operation of the device in which the multiaxial sensor 10 is mounted. In the following, the rating shall be interpreted in the same way.

The amount of displacement in each of the directions of the X-, Y-, and Z-axes is obtained for each of the applied six-axis forces Fx to Mz (step S104). The maximum displacement amount X1max of the X-axis, the maximum displacement amount Y1max of the Y-axis, and the maximum displacement amount Z1max of the Z-axis are obtained from the obtained displacement amounts for each of the six-axis forces Fx to Mz (step S105).

Next, a rated 6-axis composite force is applied (step S106). The 6-axis combined force at rated is the force to which all 6-axis forces Fx to Mz are applied simultaneously at rated. An X-axis displacement amount X6, a Y-axis displacement amount Y6, and a Z-axis displacement amount Z6 when a 6-axis composite force is applied at the rated time are obtained (step S107).

The maximum displacement amounts X1max, Y1max, Z1max of the X-, Y-, and Z-axes obtained above and the displacement amounts X6, Y6, and Z6 of the X-, Y-, and Z-axes when the 6-axis compound force is applied are , Y-axis and Z-axis, and the larger one is set as the maximum displacement amount Xmax, Ymax, Zmax of each axis (step S108).

Based on the maximum displacement amounts Xmax, Ymax, Zmax of the X-, Y-, and Z-axes thus determined, the respective lengths of the X-, Y-, and Z-axes of the clearance of the stopper structure portion SP are determined. (Step S109). The lengths of the X-, Y- and Z-axes of the gaps may be the same as the determined maximum displacement amounts Xmax, Ymax and Zmax of the X-, Y- and Z-axes, or may be slightly larger. It may be a length that has a

It is examined whether there is any problem with the material safety factor of the elastic body in the gap of the determined stopper structure portion SP (step S110). For example, it is confirmed whether or not the material safety factor of the elastic body can be ensured (for example, material safety factor>1) even when the maximum displacement occurs in the elastic body within the range of the gap. If there is a problem with the material safety factor, the design of the elastic body is redone (No in step S110, step S102).

If there is no problem with the material safety factor, the clearance angle θ and the wire diameter φ for wire cutting are obtained based on the determined clearance of the stopper structure portion SP (Yes in step S110, step S111). Here, the gap angle θ represents the angle at which the gap (tapered surface) is inclined with respect to the XY plane. The length Z of the gap in the Z-axis direction is expressed by Z=φ/cos θ. The length X of the gap in the X-axis direction is expressed by X=φ/sin θ. The length Y of the gap in the Y-axis direction is obtained in the same manner as the length X in the X-axis direction. Note that the length X in the X-axis direction and the length Y in the Y-axis direction may be different. From these equations, the gap angle θ and the wire diameter φ can be obtained.

Based on the angle θ of the gap and the diameter φ of the wire, it is examined whether wire cutting is possible (step S112). For example, if the wire cutting device cannot cope with the obtained gap angle θ, or if there is no wire corresponding to the obtained wire diameter φ, it is determined that the wire cutting cannot be performed.

If it is determined that wire cutting is not possible, the design of the elastic body is redone (No in step S112, step S102). Instead of redoing the design of the elastic body, the lengths X, Y, and Z of the gap in each axial direction may be determined again (step S109), or the angle θ of the gap and the wire diameter φ of the wire may be determined again. (step S111), or other steps may be redone.

If it is determined that the wire cutting process is possible, an elastic body is cut out from the material by wire cutting process (Yes in step S112, step S113). Thereby, an elastic body is manufactured.
Note that the shape of the multiaxial sensor 10 may be appropriately changed according to various purposes, such as weight reduction or increased sensor sensitivity. For example, like the multiaxial sensor 10a shown in FIG. 9, in the elastic body shown in FIG. good. This makes it possible to adjust the operating point of the stopper by the stopper structure portion SP, the sensitivity of the sensor, or the like.

According to the present embodiment, by providing the stopper structure portion SP that makes the tapered surfaces of the first area portion 1 (movable portion) and the second area portion 2 (fixed portion) contact with each other, the force Fx acting in the XY plane direction, The operating points of the stopper for each of Fy, Mz and the forces Fz, Mx, and My acting in the Z-axis direction can be set independently and separately.

Specifically, each length of the X-axis, Y-axis and Z-axis of the gap between the tapered surfaces of the first region portion 1 and the second region portion 2 is calculated from the amount of displacement of the elastic body due to overload. By shortening, it is possible to set the stopper in each axial direction.
Further, since the stopper structure portion SP is formed by tapering the surfaces where the first region portion 1 and the second region portion 2 face each other, the elastic structure including the first region portion 1 and the second region portion 2 is formed. The shape of the body can be a shape that can be wire cut. Specifically, wire cutting can be performed by determining the inclination angle θ of the tapered surface and the interval φ of the gap from the obtained lengths of the X-axis, Y-axis, and Z-axis of the gap.

Here, the shape that can be wire-cut is a shape that can be formed by cutting the outer shape with a straight line (wire).
In addition, the present invention is not limited to the above-described embodiments, and components may be deleted, added, or changed. Also, a new embodiment may be created by combining or exchanging constituent elements of a plurality of embodiments. Even if such an embodiment is directly different from the above-described embodiments, those having the same meaning as the present invention have been described as embodiments of the present invention, and the description thereof has been omitted.

DESCRIPTION OF SYMBOLS 1... 1st area|region part 2... 2nd area|region part 3... Strain-generating body 10... Multiaxial sensor 11... First structural part 21... Second structural part CL... Notch part H1, H2... Mounting Hole, SP... Stopper structure part.

Claims (5)

a flat plate-shaped first region located in the central portion;
a second region portion forming an elastic body integrally with the first region portion and positioned on the outer peripheral side of at least a part of the first region portion;
multiaxial force detection means for detecting forces in multiaxial directions based on the amount of relative displacement between the first area portion and the second area portion;
Included in the elastic body, the first region portion and the second region portion face each other on both sides in the circumferential direction at first tapered surfaces, and the two first tapered surfaces of the first region portion are separated from each other. a first stopper means that functions as a stopper by contacting the opposing first tapered surfaces;
A second stopper included in the elastic body, wherein the first region portion and the second region portion are radially opposed to each other at second tapered surfaces, and the opposing second tapered surfaces come into contact with each other to function as a stopper. means and
The elastic body has a shape that can be wire cut.
A multi-axis sensor characterized by : The first stopper means is a stopper against at least a vertical force perpendicular to the plane of the flat plate, a moment about the vertical direction, and a moment about the parallel direction parallel to the plane of the flat plate. functions as
2. A multi-axis sensor according to claim 1, wherein said second stopper means functions as a stopper against at least said vertical forces. 3. The multiaxial sensor according to claim 2, wherein said first stopper means functions as a stopper against said parallel force. 3. The multiaxial sensor according to claim 2, wherein said second stopper means functions as a stopper against said parallel force. Before the first stopper means or the second stopper means functions as a stopper, at least one of the first area portion and the second area portion is provided so that the first area portion and the second area portion do not come into contact with each other. 2. The multi-axis sensor of claim 1, comprising a notch provided.

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