JP2002365151A - Load detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect not only a level of a load but also a direction of the load, by deflecting each strain detecting element individually. SOLUTION: This detector is provided with a strain element 1 having a thin-walled part 1a, and provided with the plural strain detecting elements R1-R8, and a load transmission part 3 for applying a stress onto the distortion bodies R, a cushioning member 2 comprising a rubber material is provided between the strain element 1 and the load transmission part 3 in a position opposed to the strain detecting elements R1-R8, and the load applied by the load transmission part 3 is applied onto the respective strain detecting elements R1-R8 via the cushioning member 2 positioned on the strain detecting elements R1-R8, so as to deflect the respective strain detecting elements R1-R8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load detecting device used for a hand or a foot of a robot or an animal-shaped robot, and capable of detecting a magnitude of a load received by the device and a direction of the load.

[0002]

2. Description of the Related Art FIG. 6 is a side view of a conventional load detecting device, and FIG. 7 is an exploded perspective view of the conventional load detecting device.

A conventional load detecting device will be described with reference to FIGS. 6 and 7. A strain element 51 is made of a flexible metal material having a constricted portion 51a, and a strain detecting element 52 is provided on the constricted portion 51a. Four strain detecting elements 52 are connected by a bridge circuit.

[0004] The fixed end side of such a flexure element 51 is fixed to a substrate 55 by means of a bolt 56 via a spacer 53 and a lower mount 54. The free end side of the flexure element 51 is connected to the spacer 60 and the upper mount 6.
1 is attached to the tray 62 by bolts 63.

[0005] The conventional load detecting device has the above-described configuration. Next, the operation will be described. When a load F is applied to the tray 62, the free end of the strain body 51 bends and the constricted portion 5
1a is flexed on average, and this flexure causes the strain detecting element 52
Is subjected to tensile force as stress. Then, the strain detecting element 52
Changes the resistance and outputs the deviation voltage from the bridge circuit.
The weight F is calculated by converting the deviation voltage into a weight value. As described above, the conventional weight detection device detects the magnitude of the weight.

[0006]

As described above, the conventional load detecting device has a structure in which the constricted portion 51a is bent on average and the strain detecting element 52 is bent, so that only the magnitude of the load applied to the device can be measured. It was not possible to apply the device to measuring instruments and the like, and the range of application was narrow.

The present invention has been made in view of such a problem, and provides a weight detecting device capable of detecting not only the magnitude of the load but also the direction of the load by bending each strain detecting element independently. The purpose is to:

[0008]

According to a first aspect of the present invention, there is provided a weight detecting apparatus according to the present invention, comprising: a strain generator having a thin portion and provided with a plurality of strain detecting elements; A load transmitting unit that applies a stress to the detecting element, a buffer member is provided between the strain generating element and the load transmitting unit at a position facing the strain detecting element, and the buffering member is applied by the load transmitting unit. The applied load is applied to the respective strain detecting elements via the buffer member located on the strain detecting elements, and the respective strain detecting elements are bent.

As a second solution, the load transmitting portion of the load detecting device of the present invention has a plurality of projections projecting toward the strain-generating body and facing the respective strain detecting elements.
The buffer member has a plate shape, and the load applied by the protrusion is applied intensively to each of the strain detecting elements via the plate-shaped buffer member.

As a third solution, the buffer member of the load detecting device of the present invention has a plurality of projecting portions provided at positions facing each of the strain detecting elements. The load applied by the above is intensively applied to the respective strain detecting elements via the protruding portions.

As a fourth solution, the shock-absorbing member of the weight detecting device according to the present invention comprises a single plate-like base and the plurality of protrusions integrally projecting from the base toward the load transmitting unit. Department.

Further, as a fifth solution means, a pair of the strain detecting elements of the weight detecting device of the present invention are provided so as to face the front and back surfaces of the thin portion of the strain generating element.

As a sixth solution, the strain detecting element of the weight detecting device of the present invention has a plate-like shape, and a plurality of concave portions are formed so as to leave the thin portion. The configuration was such that the strain detecting element was formed.

As a seventh solution, the outer surface of the load transmitting portion of the load detecting device of the present invention has a spherical surface.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings of the load detecting device of the present invention, FIG. 1 is a sectional view of a main part of the load detecting device of the present invention, FIG. 2 is an exploded perspective view of the load detecting device of the present invention, and FIG.
FIG. 4 is a wiring circuit diagram of the load detecting device of the present invention, FIG. 4 is an explanatory diagram for explaining the operation of the load detecting device of the present invention, and FIG. 5 is a back surface of a flexure element according to a modified example of the load detecting device of the present invention. It is the perspective view seen from.

The load detecting device of the present invention will be described with reference to FIGS. 1 to 4. The strain body 1 is made of a synthetic resin molded product, and has a thin portion 1a having a substantially square thin plate shape, and the thin portion 1a. Four legs 1b extending downward from the square of 1a
And a locking portion 1c provided to protrude upward from the square.
And

The strain detecting element R is made of a material in which carbon as a conductive material is dispersed in a thermosetting resin such as epoxy, and changes its resistance value when subjected to a stress such as a compressive force or a tensile force. is there. The strain detecting elements R are formed at equal intervals at four locations as R1, R2, R3, and R4 on the surface of the thin portion 1a, and R1, R
2, R3, R4, and R5, R6, R
7 and R8 are formed at equal intervals at four locations. The reason why the strain detecting elements R are provided on the front and back surfaces of the thin portion 1a is to increase the output voltage as described later. The strain detecting elements R1 to R8 may be formed, for example, by printing a material on a thin film and forming the film on the thin portion 1a.
By adhering to the front and back surfaces with an adhesive.

These strain resistance elements R1 to R8 are:
As shown in FIG. 3, the strain resistance elements R (for example, R1 and R5) facing the front and back surfaces are connected in series, and the pair of strain resistance elements R connected in series are connected in parallel.

The cushioning member 2 is made of a rubber material and has a substantially square thin plate-like base 2a and four protrusions 2b, 2c, 2d and 2e projecting upward from the base 2a. Such a buffer member 2 is fixed to the surface of the thin portion 1a of the flexure element 1 by means of adhesion or the like, and as shown in FIG. 4, the protrusion 2b and R1, R5 are aligned in a straight line. Has become. Note that the other protrusions 2c to 2e and R2
Similarly, R4 to R4 and R6 to R8 are also arranged in a straight line. Then, for example, when the protrusion 2b is pressed,
The load is averaged and concentrated intensively through the base 2a.
a, and the thin portion 1a bends to apply a compressive force as a stress to the strain detecting element R1.
1 increases, and a tensile force is applied to the strain detection element R5, so that the resistance value of the strain detection element R5 decreases. That is, stress is applied intensively to each of the strain detecting elements R1 to R8 by the protruding portions 2b to 2e, and the stress is applied to the strain detecting element R on average by applying a load via the cushioning member 2 made of a rubber material. It has become.
Note that, without providing the base 2a, the protrusions 2b to 2e may be arranged on the strain detecting elements R1 to R4, respectively, to bend the strain detecting elements R1 to R8.

The load transmitting portion 3 is made of a synthetic resin molded product, and has a base 3a having a spherical outer surface and a flange 3b formed so as to protrude outward from the lower edge of the base 3a. And an engagement recess 3c formed by cutting out the flange portion 3b. The load transmitting portion 3 is configured such that the engaging portion 1c of the strain body 1 is engaged with the engaging concave portion 3c.
It is fixed to the flexure element 1 so that it can be tilted slightly.

When a load is applied to the load transmitting portion 3, first, when a load is applied to the apex of the spherical surface, the four protrusions 2b, 2c, 2d, and 2e are uniformly pressed by the base 3a. , The output voltage between each strain detection element R (OUT
1 to OUT4) similarly change, and the magnitude of the load can be detected by obtaining the sum of the output voltages by a microcomputer (not shown). When a load is applied to a position deviated from the apex, the load transmitting portion 3 is slightly inclined, and the protruding portion of the protruding portions 2b to 2e, which is located in the tilt direction of the load transmitting portion 3, is more strongly pressed. Thus, the strain detecting element R facing the protruding portion bends more. As described above, the pair of strain detecting elements R in the tilting direction of the load transmitting unit 3 bend more greatly, so that the output voltage between the pair of strain detecting elements R becomes the output of the other pair of strain detecting elements R. By inputting each output voltage of OUT1 to OUT4 to a microcomputer (not shown), it is possible to recognize where on the spherical surface a load is applied.
Further, since the outer surface of the load transmitting portion 3 is formed as a spherical surface, even if a load is applied to the load transmitting portion 3 from any direction, a pressing force is applied to the projecting portions 2b to 2e in the tilting direction, and the strain detecting element in the tilting direction. R (R1 to R8) bends more.

The operation of the load detecting device according to the present invention will be described with reference to FIGS. 3 and 4. First, a voltage of 3 V to 5 V is applied between Vcc and GND. R1 to R8 have the same resistance value (1 KW to
4KW), OUT1 to OUT4 have the same output voltage. When, for example, a load in the X1 direction is applied to the load transmitting unit 3, as shown in FIG. 4, the protruding portion 2b is pressed, and the strain detecting element R1 receives a compressive force via the base 2a to increase the resistance value. (MAX 1 to 2% increase), and the resistance value decreases due to the tensile force applied to the strain detecting element R5 (MIN).
1 to 2%), and the ratio of the resistance values of the strain detection elements R1 and R5 changes. Then, the output voltage of OUT1 shown in FIG.
It becomes larger than other OUT2-4 and becomes O by microcomputer.
It is recognized that the value of only UT1 has increased, and X1
It can be detected that a load is applied in the direction. Further, when both of the strain detecting elements R1 and R5 bend, the difference between the resistance values of the two becomes large, and the value of the output voltage of OUT1 becomes OUT2.
4 can be made larger. Therefore, even with a small load, both the magnitude and the direction can be detected.

Further, by inputting the output voltage of OUT1 to the microcomputer, the magnitude of the load can be detected by converting the amount of change in the voltage value into a weight value. When the load applied to the load transmitting unit 3 is released, the return force of the cushioning member 2 causes
The load transmitting unit 3 returns to the original position, and the output voltage also returns to the original value. As described above, the load detection device of the present invention can detect the direction of the load in addition to the magnitude of the load. In the X2 direction, the Y1 direction, and the Y2 direction, the magnitude of the load and the direction of the load can be similarly detected.

When the load transmitting member 3 receives a load in a direction (oblique direction) between the X1 direction and the Y1 direction, the strain resistance elements R1, R5, and R5 are provided via the protrusions 2b and 2c.
2 and R6 flex, respectively, and the output voltages of OUT1 and OUT2 change. Then, the microcomputer outputs OUT1 to OUT
By recognizing that the balance of each output voltage has changed by inputting a value of 4, it is possible to detect that a load is applied in an oblique direction. Also,
The magnitude of the load can be detected by calculating the sum of the change amounts of the output voltages of OUT1 and OUT2. Since the returning operation of the load transmitting unit 3 is the same as that in the X1 direction, the detailed description is omitted here.

The load detecting device of the present invention operates and operates as described above. However, it is needless to say that the present invention is not limited to the above-described structure. As a modification, as shown in FIG. A plurality of recesses 1d are provided except for the portion 1a, and strain detecting elements R (R1 to R8) are provided on the front and back surfaces of the thin portion 1a formed by the respective recesses 1d in the same manner as the arrangement described above. May be. When the thin portion 1a is formed by the concave portion 1d in this way, when a certain thin portion 1a is bent, the influence of the bending is reduced to other thin portions 1a, and the reliability is further reduced. , The strain detecting element R can be flexed independently, and the output reliability is improved.

In the configuration of the above-described embodiment, the projections 2b to 2c are used as the cushioning members 2. However, four projections are integrally provided on the lower surface of the load transmitting unit 3,
The buffer member 2 may be a plate-shaped base only, and the load applied by the protrusion may be intensively applied as a stress to each strain detection element via the buffer member. Further, in the embodiment, an example in which a rubber material is used as the buffer member 2 has been described, but it goes without saying that any material having elasticity can be applied.

[0027]

The load detecting device according to the present invention comprises a strain generating body having a thin portion and provided with a plurality of strain detecting elements, and a load transmitting section, and a load transmitting section is provided between the strain generating body and the load transmitting section. A buffer member is provided at a position facing the strain detecting element, and the load applied by the load transmitting unit is applied to each of the strain detecting elements via the buffer member located on the strain detecting element, and each of these strain detecting elements is provided. Since a plurality of strain detecting elements can be bent independently, a load detecting device capable of detecting not only the magnitude of the load but also the direction of the load can be provided.

The load transmitting portion of the load detecting device according to the present invention has a plurality of projections facing each of the strain detecting elements, and the buffer member has a plate-like shape, and the load applied by the projections is a plate-like buffer. Provided is a load detection device capable of more flexibly independently bending a plurality of strain detection elements by a projection because the configuration is such that a plurality of strain detection elements are intensively added to the detection element via a member, and a direction of a load can be more reliably detected. be able to.

Further, the buffer member of the load detecting device of the present invention has a plurality of protrusions provided at positions opposed to the respective strain detecting elements, and the load applied by the load transmitting unit is applied to the protrusions. A load detecting device that can flexibly and independently bend the plurality of strain detecting elements independently by the protruding portion, and more reliably detect the direction of the load. can do.

Further, the shock absorbing member of the weight detection device of the present invention is constituted by a single plate-like base and a plurality of protrusions integrally projecting from the base toward the load transmitting portion. Since one buffer member is constituted by the protruding portion and the base portion, the number of parts is reduced, and it is possible to provide a load detecting device having good assemblability and mass productivity.

Further, since the strain detecting element of the weight detecting device of the present invention is provided in a pair so as to face the front and back surfaces of the thin portion of the strain body, the thin portion bends.
Since the resistance value of the pair of front and back strain detecting elements changes, the output voltage between the bent strain detecting elements can be increased, and a high-performance load detecting device capable of detecting even a small load can be provided. .

The strain detecting element of the weight detecting device of the present invention has a plate shape, a plurality of recesses formed so as to leave a thin portion, and a strain detecting element formed on the front and back surfaces of the thin portion. Accordingly, the thin portions provided by the respective concave portions bend without affecting each other, so that each of the strain detecting elements can be bent more reliably.

Further, since the outer surface of the load transmitting portion of the load detecting device of the present invention has a spherical surface, the direction of the load is transmitted to the strain detecting element more reliably, and the direction of the load can be detected more reliably. A high-performance load detecting device can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a load detecting device according to the present invention.

FIG. 2 is an exploded perspective view of the load detecting device of the present invention.

FIG. 3 is a wiring circuit diagram of the load detection device of the present invention.

FIG. 4 is an explanatory diagram for explaining the operation of the load detection device of the present invention.

FIG. 5 is a perspective view of a strain sensing element according to another modified example of the load detection device of the present invention as viewed from the back surface.

FIG. 6 is a side view of a conventional load detecting device.

FIG. 7 is an exploded perspective view of a conventional load detecting device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 strain generating body 1a thin portion 1b leg portion 1c locking portion 1d concave portion 2 buffer member 2a base portion 2b to 2e projecting portion 3 load transmitting portion 3a base 3b flange portion 3c engaging concave portion 3c R1 to R8 strain detecting element

Claims (7)

[Claims] 1. A strain generating element having a thin portion and provided with a plurality of strain detecting elements, and a load transmitting section for applying a stress to the strain detecting element, wherein the load transmitting section applies a stress to the strain detecting element. Between them, an impact member is provided at a position facing the strain detection element, and the load applied by the load transmitting unit is applied to each of the strain detection elements via the buffer member located on the strain detection element. In addition, each of the strain detecting elements bends in addition thereto. 2. The load transmitting section has a plurality of projections protruding toward the strain body and facing the respective strain detecting elements, the buffer member has a plate shape, and a load applied by the projections. The load detecting device according to claim 1, wherein the load is applied to each of the strain detecting elements intensively through the plate-shaped buffer member. 3. The buffer member has a plurality of protrusions provided at positions facing each of the strain detecting elements, and loads applied by the load transmitting unit are concentrated through the protrusions. The load detecting device according to claim 1, wherein the load detecting device is added to each of the strain detecting elements. 4. The buffer member according to claim 1, wherein the buffer member comprises a single plate-shaped base and the plurality of protrusions integrally projecting from the base toward the load transmitting unit. 3. The load detection device according to 3. 5. The load detecting device according to claim 1, wherein a pair of the strain detecting elements are provided so as to face front and back surfaces of the thin portion of the strain body. apparatus. 6. The strain generating element has a plate shape, a plurality of recesses are formed so as to leave the thin portion, and the strain detecting element is formed on the front and back surfaces of the thin portion. The load detecting device according to claim 5, wherein 7. The load detecting device according to claim 1, wherein an outer surface of the load transmitting section has a spherical surface.