KR102015784B1 - Multi-axis load cell - Google Patents

Abstract

The present invention relates to a multiaxial load cell, which has a simple body structure, and can simplify the configuration of a circuit detecting power of three directions (Fx, Fy, Fz) and torque of three directions (Mx, My, Mz). To this end, the multiaxial load cell of the present invention comprises: a body composed of an upper plate, a lower plate arranged to be spaced from a lower portion of the upper plate while being bent by a load applied by the upper plate, and vertical first, second, third, and fourth pillars which connect the upper plate to the lower plate while being bent and sheared by the load applied by the upper plate; a sensing means attached to the body, and detecting the bending and shearing deformation rate of the body before outputting the same as a signal, thereby allowing the power of three directions (Fx, Fy, Fz) and the torque of three directions (Mx, My, Mz) to be measured; a supporter to which a lower portion of the body is fixated, and which is fixated to a fixating unit of a system on which the multiaxial load cell is mounted; and a case which limits the body therein to surround and protect the body, while allowing the upper plate of the body to protrude to be fixated to a load unit of the system, and is fixated to the supporter.

Description

Multi-Axis Load Cells {MULTI-AXIS LOAD CELL}

The present invention relates to a multi-axis load cell which makes it possible to measure forces in three directions (Fx, Fy, Fz) and torques in three directions (Mx, My, Mz).

Among the multi-axis load cells, the 6-axis load cell, as anyone knows, can detect and measure three directions of force (Fx, Fy, Fz) and three directions of torque (Mx, My, Mz). A variable resistor called a strain gauge is attached to the sensing unit.

The strain gauge described above is attached to an elastic body that is the material of the body of the six-axis load cell to electrically display the physical change amount of the elastic body. The strain gauge is composed of four or eight pieces to constitute a Wheatstone bridge circuit.

On the other hand, the six-axis load cell is processed into a single body for precision measurement because it is difficult to measure precisely due to assembly and processing errors when composed of a number of parts from the structural aspect.

However, when a six-axis load cell measuring force in multiple directions receives a force in one direction, the force is transmitted not only to the force sensing portion but also to the force sensing portion in the other direction, which prevents accurate measurement. .

In order to solve this problem, the shape of the sensing unit is reduced to a measurement error by using a cross-shaped (+) type or a method of dividing each sensing area.

However, the aforementioned methods have a problem in that the manufacturing cost increases because the structure is complex and the circuit for canceling the mutual interference error for each force is complicated. There is another problem that the manufacturing cost increases and the production period is long because it is difficult to manufacture the number of shafts to order.

Related prior arts include "Korean Patent No. 10-1115418", "Korean Patent No. 10-1481784", "Korean Patent No. 10-1455307", and "Korean Patent No. 10-1759102". .

The present invention has a simple structure of the body, to provide a multi-axis load cell that can simplify the circuit configuration for sensing the force (Fx, Fy, Fz) in three directions and the torque (Mx, My, Mz) in three directions will be.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above.

In the present invention for achieving the above object, in the multi-axis load cell, the multi-axis load cell, the lower plate is arranged in the lower portion of the upper plate and bent deformation by the load applied from the upper plate, and between the upper plate and the lower plate, A body having vertical first, second, third and fourth pillars which are bent and sheared by a load applied from the top plate; Sensing means attached to the body detects the bending and shear strain of the body and outputs it as a signal to measure the force in three directions (Fx, Fy, Fz) and torque in three directions (Mx, My, Mz); A pedestal fixed to the lower part of the body and fixed to a fixed part of the system in which the multi-axis load cell is mounted; And a case in which the body is limited to the inside so as to surround and protect the body, and the upper plate of the body protrudes to be fixed to the load portion of the system, and is fixed to the pedestal. Eight strain gauges for sensing force Fx forming a sensing circuit; Eight strain gauges for sensing force Fy connected in a Wheatstone bridge form to form a second sensing circuit; Thirty-two strain gauges connected in a Wheatstone bridge shape and sensing force Fz forming a sixth sensing circuit; Eight strain gauges sensing torque Mx connected in a Wheatstone bridge form to form a third sensing circuit; Eight strain gauges for sensing torque My connected in a Wheatstone bridge form to form a fourth sensing circuit; And eight strain gauges connected in a Wheatstone bridge form to sense torque Mz forming a fifth sensing circuit, wherein four of the eight strain gauges detecting force Fx are angles of the outer long sides of the first pillar. Attached to the corner side, another four are attached to each corner side of the outer long side of the third column facing the first column, and four of the eight strain gauges sensing force Fy are the outer long side of the second column Is attached to each corner side of the edge, and another four are attached to each edge side of the outer long side of the fourth column facing the second column, and 16 of the 32 strain gauges sensing force Fz are of the octagonal shape. Of the eight strain gauges attached to the upper surface of the lower plate adjacent to the eight sides of the lower plate provided the plate shape, another 16 are attached to the lower surface of the lower plate adjacent to the eight sides of the lower plate and sensing torque Mx. 2 The dog is attached between two strain gauges that detect the force Fx attached to the upper both corners of the first column, and the other two are two strain gauges that detect the force Fx attached to the lower both corners of the first column. Between the two strain gages, which detect the force Fx attached to the upper both corners of the third column, and the other two to the lower both corners of the third column. It is attached between two strain gauges detecting Fx, two of eight strain gauges detecting torque My are attached between two strain gauges detecting force Fy attached to the upper both edges of the second column, Another two are attached between the two strain gauges that detect the force Fy attached to the bottom both edges of the second pole, and another two to the top both edges of the fourth pole. Attached between two strain gauges detecting attached force Fy, another two attached between two strain gauges detecting force Fy attached to the bottom both edges of the fourth column, and sensing torque Mz Two of the eight strain gauges are attached to the first column, another two to the second column, another two to the third column, and two to the fourth column. It can be attached adjacent to the top side of the first, second, third and fourth pillars at the central portion of the outer long side of the third and fourth pillars.

Specifically, the upper plate is provided in a horizontal disk shape, the first through hole is formed in the center of the upper plate, a plurality of first connecting holes may be formed on the upper surface of the upper plate to be connected to the load portion of the system via a bolt. have.

Specifically, the first to fourth pillars are disposed to be symmetrically rotated by 90 degrees along an arc of an imaginary circle concentric with the upper plate, wherein the upper and lower ends of the first to fourth pillars are respectively the lower surface of the upper plate and the upper portion of the lower plate. The upper surface of the first and fourth pillars and the lower surface of the upper plate and the lower surface of the first and fourth pillars and the upper surface of the lower plate may be smoothly connected so that stress is not concentrated.

More specifically, each of the first to fourth pillars has two long sides facing each other horizontally and a quadrangular cross section having two short sides connecting both ends of the two long sides when facing each other horizontally. The fourth pillars may be arranged such that one long side faces the center of the virtual circle.

Specifically, the lower plate is provided in a flat octagonal plate shape in which a second through hole is formed in the center, and a plurality of slit holes are formed in the lower plate, and the slit holes are formed outside the first to fourth pillars connected to the lower plate and at the same time It is formed between the first to fourth pillars are formed to vertically penetrate the lower plate, the eight sides of the lower plate may be formed to extend the "∞" shaped induction grooves toward the center of the lower plate.

More specifically, the slit balls have an inequality shape that opens their mouth toward the center of the bottom plate when the bottom plate is viewed in plan, and the sensing guide grooves extend only to adjacent slit holes, with two convex portions and two concave portions of each sensing guide groove. Strain gauges for sensing the force Fz of the sensing means may be attached to the upper and lower surfaces of the lower plate facing the lower plate.

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Specifically, a plurality of bolt fastening holes are formed in the lower plate so as to be connected to the pedestal via a bolt, and the upper surface of the pedestal is formed so that the stepped portions protrude at positions corresponding to the plurality of bolted fastening holes, and bolted to the stepped portions. Bolt fastening grooves corresponding to the ball are formed, and a plurality of second connecting holes may be formed on the lower surface of the pedestal so as to be connected to the fixing part of the system via a bolt.

Specifically, the case is provided in a hollow housing shape, the side is closed and the bottom is opened, the upper portion is provided with an exposed hole for protruding the upper plate of the body is formed, the side of the case is formed of sensing means Connector mounting holes for guiding the first to sixth sensing circuits are formed, and the case and the pedestal are fixed by bolts, and the case facing the outer circumferential surface of the pedestal is provided with a fixing hole, and the pedestal is formed with a fixing groove corresponding to the fixing hole. Can be.

As described above, the multi-axis load cell according to the present invention has an advantage of significantly lowering the manufacturing cost and increasing the production efficiency because the structure and the circuit configuration of the body are simple.

In addition, the multi-axis load cell according to the present invention can not only reduce the man-hour for circuit configuration work because the circuit configuration is simple, but also reduce the errors in the circuit configuration, so that anyone can easily configure the circuit without a skilled worker. There is an advantage to this.

1 is a perspective view showing a multi-axis load cell according to the present invention,
FIG. 2 is an exploded perspective view illustrating an exploded view of the multi-axis load cell shown in FIG. 1;
3 is a view showing the cross-sectional shape of the pillars shown in FIG.
4A is a view showing a state in which a strain gauge is attached to the first pillar shown in FIG.
4B is a view showing a state in which a strain gauge is attached to the third pillar shown in FIG.
4C is a view showing a state in which a strain gauge is attached to the second pillar shown in FIG.
4D is a view showing a state in which a strain gauge is attached to the fourth pillar shown in FIG.
5A is a view showing a state in which a strain gauge is attached to the upper surface of the lower plate shown in FIG.
5B is a view showing a state in which a strain gauge is attached to the lower surface of the lower plate shown in FIG.
6 is a view showing the direction of the force and the distribution of the force when the force Fz is applied to the multi-axis load cell according to the present invention,
7 is a view showing a deformation shape using the finite element analysis method when the force Fz is applied to the multi-axis load cell according to the present invention,
8 is a view showing the direction of the force and the distribution of the force when the force Fx is applied to the multi-axis load cell according to the present invention,
9 is a view showing a shape modified by the finite element analysis method when the force Fx is applied to the multi-axis load cell according to the present invention,
10 is a view showing the direction of the force and the distribution of the force when the torque Mx is applied to the multi-axis load cell according to the present invention,
11 is a view showing a shape modified using the finite element analysis method when the torque Mx is applied to the multi-axis load cell according to the present invention,
12 is a view showing the direction of the force and the distribution of force when the torque Mz is applied to the multi-axis load cell according to the present invention, and
FIG. 13 is a view showing a shape deformed using a finite element analysis method when torque Mz is applied to a multi-axis load cell according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. Like elements in the figures are denoted by the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 to 3 is a view showing a multi-axis load cell according to the present invention, the multi-axis load cell 100 according to the present invention is bent and sheared by the load body 110 and attached to the body 110 Sensing means for sensing the bending and shear strain of the body 110 and outputs it as a signal to measure the force in three directions (Fx, Fy, Fz) and torque in three directions (Mx, My, Mz) do.

Here, the three-way force (Fx, Fy, Fz) is measured by detecting the bending strain of the body 110, the torque in three directions (Mx, My, Mz) is measured by detecting the shear strain of the body 110 do.

In addition, the multi-axis load cell 100 according to the present invention is limited to the base 110 and the body 110 to be wrapped around the base 110 and the body 110 is fixed to the lower portion of the body 110, the body 110 It further includes a case 140 protruding the upper portion of the fixed to the pedestal 130.

First, the body 110 is manufactured in one piece by processing one block material. The body 110 is the upper plate 112, the lower plate 120 which is spaced apart from the lower portion of the upper plate 112, and the vertical first, second, and first to connect between the upper plate 112 and the lower plate 120 Third and fourth pillars 118a, 118b, 118c, 118d.

Top plate 112 is a portion connected to the load portion of the system (not shown), the top plate 112 forms the upper portion of the body (110).

Here, the system refers to various devices on which the multi-axis load cell 100 according to the present invention is mounted.

Top plate 112 is provided in a horizontal disk shape having a predetermined thickness as shown, the first through hole 114 is formed in the center thereof.

That is, the upper plate 112 is provided in an annular ring shape having an inner diameter and an outer diameter concentric with the inner diameter in plan view.

In addition, a plurality of first connection holes 116 are formed on the upper surface of the upper plate 112 so that the load portion of the system may be connected via a bolt, and an internal thread is formed on the inner circumferential surface of the first connection hole 116. do.

The first, second, third, and fourth pillars 118a, 118b, 118c, and 118d are portions that are bent and sheared by load, and the first, second, third, and fourth pillars 118a, 118b, 118c, 118d), the force Fx, the force Fy and the torque Mx, the torque My, the torque Mz are detected.

The first, second, third, and fourth pillars 118a, 118b, 118c, and 118d are disposed along an arc of an imaginary circle C1 (see FIG. 3) concentric with the top plate 112. The second, third, and fourth pillars 118a, 118b, 118c, and 118d are disposed to be rotationally symmetric with each other by 90 degrees.

Each of the pillars 118a, 118b, 118c, and 118d disposed as described above connects the upper plate 112 and the lower plate 120 as described above, and for this purpose, the upper end of the pillars 118a, 118b, 118c, and 118d is firstly formed. The lower surface of each of the pillars 118a, 118b, 118c, and 118d is connected to the upper surface of the lower plate 120 so as not to interfere with the through hole 114.

At this time, the upper surface of each of the pillars (118a, 118b, 118c, 118d) and the lower surface of the upper plate 112 and the lower surface of each of the pillars (118a, 118b, 118c, 118d) and the upper surface of the lower plate 120 is stressed It is connected smoothly to prevent notch effects.

In one example, the top and bottom surfaces of each pillar 118a, 118b, 118c and 118d and the bottom and top surfaces of each pillar 118a, 118b, 118c and 118d are illustrated. As shown, it may be connected in the form of a concave curved curvature, or in the form of a chamfer although not shown.

On the other hand, each of the vertically extending pillars 118a, 118b, 118c, 118d is a rectangular cross section, preferably two long sides (W) facing each other horizontally and two connecting the two ends of the two long sides (W) Each of the pillars 118a, 118b, 118c, and 118d has a short side T, and each of the pillars 118a, 118b, 118c, and 118d is disposed such that one long side W faces the center of the virtual circle C1.

One of the two long sides W of each of the pillars 118a, 118b, 118c, and 118d senses the bending and shear strain of each of the pillars 118a, 118b, 118c, and 118d and transmits the force as an output signal. Sensing means are attached to enable measuring Fx, force Fy and torque Mx, torque My, torque Mz.

The lower plate 120 is a part forming the lower portion of the body 110, the lower plate 120 is bent deformation by the load and the force Fz is sensed in the lower plate 120.

The lower plate 120 has a predetermined thickness and is provided in a flat octagonal flat plate shape that is inscribed or circumscribed to an imaginary circle C2 (refer to FIG. 3) concentric with the upper plate 112, and has a central portion thereof. The second through hole 122 is formed in the column 118a, 118b, 118c, and 118d so as not to interfere with the pillars 118a, 118b, 118c, and 118d.

Here, the first through hole 114 and the second through hole 122 is used to process the body 110, in particular between the top plate 112 and the lower plate 120, the pillars (118a, 118b, 118c, 118d) It is formed for processing integrally.

On the other hand, in the center of the eight sides (邊) of the lower plate 120, the sensing guide grooves 124 of approximately "∞" shape extending toward the center of the lower plate 120 is formed, the lower plate 120 is formed with a slit ( Slit holes 126 are formed by vertically penetrating the lower plate 120, wherein the slit holes 126 are formed outside the pillars 118a, 118b, 118c, and 118d, and at the same time, the pillars 118a, 118b, 118c, 118d).

Preferably, the slit holes 126 are formed in the shape of a conventional inequality that opens the mouth toward the center of the lower plate 120 when the lower plate 120 is viewed in a plan view. More preferably, the sensing guide grooves 124 extending toward the center of the lower plate 120 extend only to adjacent slit holes 126.

Here, the sensing guide grooves 124 easily bend and at the same time easily bend deformation by the force Fz that the upper and lower surfaces of the lower plate 120 adjacent to the eight sides of the lower plate 120 are transmitted. To be. In addition, the slit holes 126 travel from the top plate 112 along the pillars 118a, 118b, 118c, and 118d to prevent the force Fz from dispersing. To the eight sides of the

And the upper and lower surfaces of the lower plate 120 adjacent to the eight sides of the lower plate 120 detects the bending strain of the upper and lower surfaces of the lower plate 120 and transmits it as an output signal to measure the force Fz. Sensing means is attached to enable it.

The sensing means includes eight strain gauges (Fx1, ..., Fx8) for detecting force Fx, eight strain gauges (Fy1, ..., Fy8) for detecting force Fy and 32 strain gauges (Fz1, for detecting force Fz). ..., Fz32).

In addition, the sensing means includes eight strain gauges (Mx1, ..., Mx8) for detecting torque Mx, eight strain gauges (My1, ..., My8) for detecting torque My, and eight strain gauges (Mz1, for detecting torque Mz). ..., Mz8) is further included.

Here, strain gauges Fx1, ..., Fx8 for detecting force Fx and strain gauges Fy1, ..., Fy8 for detecting force Fy are attached to pillars 118a, 118b, 118c, and 118d, and torque Mx as well. Strain gauges (Mx1,…, Mx8) for sensing the torque, 8 strain gauges (My1,…, My8) for torque My, and strain gauges (Mz1,…, Mz8) for detecting the torque Mz are also columns (118a, 118b, 118c). 118d).

Strain gauges Fz1,..., Fz32 for detecting the force Fz are attached to the lower plate 120.

In one example, four of the eight strain gauges Fx1, ..., Fx8 sensing force Fx are the outer long sides W of the first column 118a, as shown in Figure 4a. The remaining four strain gauges (Fx5, ..., Fx8), which are attached to each corner side of) and sense the force Fx, are formed of the third pillar 118c facing the first pillar 118a as shown in FIG. 4B. Attached to each corner side of the outer long side W, the eight strain gauges Fx1, ..., Fx8 for sensing the force Fx thus attached are connected in the form of a conventional wheatstone bridge to form a first sensing circuit. To form.

Four strain gauges Fy1, ..., Fy4 of the eight strain gauges Fy1, ..., Fy8 for detecting the force Fy are formed on the outer long side W of the second pillar 118b, as shown in FIG. The remaining four strain gauges Fy5,..., Fy8 attached to each corner side and detecting the force Fy are the outer long sides of the fourth pillar 118d facing the second pillar 118b as shown in FIG. 4D. Attached to each corner side of (W), the eight strain gauges Fy1,..., Fy8 for sensing the attached Fy are connected in the form of a normal Wheatstone bridge to form a second sensing circuit.

Meanwhile, four strain gauges Mx1, ..., Mx4 of the eight strain gauges Mx1, ..., Mx8 for detecting the torque Mx have an outer long side W of the first pillar 118a, as shown in FIG. 4A. Wherein two strain gauges (Mx1, Mx2) are attached side by side between strain gauges (Fx1, Fx2) that sense the force Fx attached to the upper both edges of the first column (118a). Strain gauges Mx3 and Mx4 are attached side by side between strain gauges Fx3 and Fx4 that sense the force Fx attached to both bottom edges of the first pillar 118a. The remaining four strain gauges Mx5,..., Mx8 sensing torque Mx are attached to the outer long side W of the third pillar 118c facing the first pillar 118a as shown in FIG. 4B. In this case, the two strain gauges (Mx5, Mx6) are attached side by side between the strain gauges (Fx5, Fx6) for detecting the force Fx attached to the upper both edges of the third column (118c), and another two strain gauges ( Mx7 and Mx8 are attached side by side between strain gauges Fx7 and Fx8 that sense the force Fx attached to the bottom edges of the third pillar 118c. The eight strain gauges Mx1, ..., Mx8 for sensing the attached torque Mx are connected in the form of a normal Wheatstone bridge to form a third sensing circuit.

In addition, four strain gauges Mx1, ..., Mx4 of the eight strain gauges My1, ..., My8 that sense torque My are the outer long sides W of the second pillar 118b, as shown in FIG. 4C. Wherein two strain gauges (My1, My2) are attached side by side between strain gauges (Fy1, Fy2) that sense the force Fy attached to the upper both edges of the second column (118b). Strain gauges My3 and My4 are attached side by side between strain gauges Fy3 and Fy4 that sense the force Fy attached to both bottom edges of the second column 118b. The remaining four strain gauges My5,..., My8 sensing torque My are attached to the outer long side W of the fourth pillar 118d facing the second pillar 118b as shown in FIG. 4D. do. At this time, the two strain gauges (My5, My6) are attached side by side between the strain gauges (Fy5, Fy6) for detecting the force Fy attached to the upper both corners of the fourth column (118d), another two strain gauges (My7) , My8 is attached side by side between the strain gauges (Fy7, Fy8) for detecting the force Fy attached to the bottom both sides of the fourth pillar (118d). The eight strain gauges My1, ..., My8 for sensing the attached torque My are connected in the form of a normal Wheatstone bridge to form a fourth sensing circuit.

The eight strain gauges Mz1,..., Mz8 for detecting torque Mz each have a pair of outer long sides W of the first, second, third, and fourth pillars 118a, 118b, 118c, and 118d. Abuts to the top side of the first, second, third and fourth pillars 118a, 118b, 118c, 118d approximately at the central portion of The eight strain gauges Mz1, ..., Mz8 for sensing the attached torque Mz are connected in the form of a normal Wheatstone bridge to form a fifth sensing circuit. For example, two of the eight strain gauges My1, ..., My8, Mz1, Mx2, which sense torque Mz, as shown in FIGS. 4A to 4D, are connected to the first pillar 118a and another two. Mz3 and Mx4 are attached to the second pillar 118b, another two Mz5 and Mx6 are attached to the third pillar 118c, and another two Mz7 and Mx8 are attached to the fourth pillar. do.

Meanwhile, 16 strain gauges Fz1, ..., Fz16 among the 32 strain gauges Fz1, ..., Fz32 for detecting the force Fz are disposed on eight sides of the lower plate 120 as shown in FIG. 5A. The remaining 16 strain gauges Fz17,..., Fz32 are attached to the upper surface of the adjacent lower plate 120, and as shown in FIG. 5B, the lower plate 120 adjacent to the eight sides of the lower plate 120 is shown. It is attached to the bottom surface.

At this time, the sixteen strain gauges (Fz1, ..., Fz16) attached to the upper surface of the lower plate 120 is attached to face two convex portions of the adjacent sensing guide groove 124 while forming a pair of two, similarly the lower plate The sixteen strain gauges Fz17,..., Fz32 attached to the lower surface of the 120 are attached to the two concave portions of the adjacent sensing guide grooves 124 in a pair of two.

Here, the convex portion of the sensing induction groove 124 means two parts that are convexly curved to the upper side when the sensing induction groove 124 is viewed from the front, and the concave portion of the sensing induction groove 124 is the sensing induction groove ( 124) means two portions that are concavely curved to the lower side when viewed from the front.

The 32 strain gauges Fz1, ..., Fz32 for sensing the attached force Fz are connected in the form of a normal Wheatstone bridge to form a sixth sensing circuit.

Meanwhile, since the first to sixth sensing circuits connected in the form of a Wheatstone bridge are known in the art, a detailed description thereof will be omitted.

As such, the body 110 to which the sensing means is attached is protected by the pedestal 130 and the case 140.

Referring back to FIGS. 1 and 2, the pedestal 130 is a part fixed to the fixing part of the system, and the pedestal 130 has a horizontal area that can support and support the lower plate 120 of the body 110. It is provided in a disk shape, the pedestal 130 and the lower plate 120 of the body 110 is connected via a conventional bolt (bolt).

To this end, the lower plate 120 preferably does not interfere with the 32 strain gauges Fz1,..., Fz32, the slit holes 126, and the sensing guide grooves 124 that detect the force Fz. At the vertex portion of the plurality of bolt fastening holes 128 are formed to vertically penetrate the lower plate 120. And the upper surface of the pedestal 130 is formed so that the stepped portion 132 protrudes in a position corresponding to the bolt fastening hole 128, the fastening bolt corresponding to the bolt fastening hole 128 in the stepped portion (132) Grooves 134 are formed.

That is, when the pedestal 130 and the lower plate 120 are connected, the bolt is fastened to the bolt fastening groove 134 by passing through the bolt fastening hole 128 at the upper surface side of the lower plate 120, whereby the pedestal ( 130 and the lower plate 120 are connected. Here, the female thread engaging with the threaded portion of the bolt is formed on the inner peripheral surface of the bolt fastening grooves (132).

In addition, the stepped portions 132 formed on the upper surface of the pedestal 130 have strain gauges Fz17,..., Fz32 that detect the force Fz attached to the lower surface of the lower plate 120. Do not become.

On the other hand, a plurality of second connection holes (not shown) are formed in the lower surface of the pedestal 130 so as to be connected to the fixing portion of the system via a bolt, and the female connector is formed in the inner circumferential surface of the second connection hole. do.

The case 140 is provided in an empty housing shape to surround and protect the body 110 to which the sensing means is attached, and to expose the upper plate 112 of the body 110 to protrude from the upper portion of the case 140. The exposed hole 142 is formed, the side is closed, the lower portion is provided to be opened.

That is, the body 110 to which the sensing means is attached is limited to the inside of the case 140 through the open lower portion of the case 140, and the pedestal 130 connected to the lower plate 120 of the body 110 also includes the case ( 140).

In this case, a connector mounting hole 144 may be formed on the side surface of the case 140 to guide the first to sixth sensing circuits to the outside of the case 140.

Here, the upper plate 112 of the body 110 exposed through the exposure hole 142 is connected to the load portion of the system as described above.

And the case 140 is connected to the pedestal 130 via a conventional bolt (bolt), one or more fixing holes 146 are formed in the case 140 facing the outer circumferential surface of the pedestal 130, The fixing groove 148 corresponding to the fixing hole 146 is formed on the outer circumferential surface of the pedestal 130.

That is, when fixing the case 140 to the pedestal 130, a bolt is fastened to the fixing groove 148 through the fixing hole 146 of the case 140, whereby the case 140 is a pedestal ( 130). Here, the internal thread of the fixing grooves 148 is formed with a female thread engaging with the threaded portion of the bolt.

Hereinafter, the distribution of the direction and force of the force when the force (Fx, Fy, Fz) and torque (Mx, My, Mz) is applied to the multi-axis load cell 100 according to the present invention, and the force (Fx, Fy, The shape change of the multi-axis load cell 100 according to the present invention with respect to Fz) and torques Mx, My, and Mz will be briefly described.

Figure 6 is a view showing the direction of the force and the distribution of force when the force Fz is applied to the multi-axis load cell according to the present invention, Figure 7 is a finite element when the force Fz is applied to the multi-axis load cell The figure which shows the shape deformed using the analysis method.

Here, in the case of the force Fz, which is a load in the Z direction, since the influence is great, it has a great influence in detecting other forces Fx and Fy and torques Mx, My and Mz. Accordingly, in the present invention, only the sensing unit (the upper and lower surfaces adjacent to eight sides of the lower plate 120) for detecting the force Fz is separated to implement the multi-axis load cell 100 according to the present invention.

When the force Fz acts on the upper plate 112 as shown in FIG. 6, the force Fz is transmitted to the lower plate 120 via the respective pillars 118a, 118b, 118c and 118d. The force Fz transmitted to the lower plate 120 is transmitted to the sensing unit sensing the force Fz through the slit holes 126, that is, the upper and lower surfaces adjacent to eight sides of the lower plate 120.

As described above, when the force Fz is transmitted to the sensing unit that detects the force Fz, a force opposing the force Fz is generated at the stepped portion 132 of the pedestal 130 fixed to the fixed portion of the system. In the lower plate 120 which is in contact with the jaw portion 132, the most sag occurs, and the largest bending deformation occurs on both sides thereof (see FIG. 7).

And when a bending deformation occurs in the sensing unit for detecting the force Fz, that is, the upper and lower surfaces adjacent to the eight sides of the lower plate 120, the force attached to the upper and lower surfaces adjacent to the eight sides of the lower plate 120 The 32 strain gauges (Fz1, ..., Fz32) that sense Fz detect this and output it as a signal, and the force Fz can be measured by the output signal.

8 is a view showing the direction of the force and the distribution of force when the force Fx is applied to the multi-axis load cell according to the present invention, Figure 9 is a finite element when the force Fx is applied to the multi-axis load cell according to the present invention Figure 10 is a view showing a deformation shape using the analysis method, Figure 10 is a view showing the direction of the force and the distribution of force when the torque Mx is applied to the multi-axis load cell according to the present invention, Figure 11 is according to the present invention Figure showing the shape deformed using the finite element analysis method when the torque Mx is applied to the multi-axis load cell.

Here, the forces Fx and Fy, and the torque Mx and the torque My have the same type of force and torque distribution and deformation behavior symmetrically with respect to the Cartesian coordinate system. Only Mx will be described.

As the force Fx acts on the top plate 112 as shown in FIG. 8, the force Fx is transmitted to the respective pillars 118a, 118b, 118c and 118d. When the force Fx is transmitted to each of the pillars 118a, 118b, 118c, and 118d, the first pillar 118a and the third pillar of the pillars 118a, 118b, 118c, and 118d which are perpendicular to the X-axis direction. Reference numeral 118c causes bending deformation in the X-axis direction by the force Fx (see FIG. 9).

When the bending deformation occurs in the first pillar 118a and the third pillar 118c by the force Fx, eight strain gauges for detecting the force Fx attached to the first pillar 118a and the third pillar 118c ( Fx1, ..., Fx8) detects this and outputs it as a signal, and the force Fx can be measured by the output signal.

When the torque Mx acts on the upper plate 112 as shown in FIG. 10, the first pillar 118a and the third pillar 118c placed perpendicular to the X axis in the X axis direction are in the Y axis direction by the torque Mx. This causes shear deformation (see FIG. 11).

When the shear deformation occurs in the first column 118a and the third column 118c by the torque Mx, eight strain gauges for detecting the force Mx attached to the first column 118a and the third column 118c ( Mx1, ..., Mx8) detects this and outputs it as a signal, and the force Mx can be measured by the output signal.

12 is a view showing the direction of the force and the distribution of force when the torque Mz is applied to the multi-axis load cell according to the present invention, Figure 13 is a finite element when the torque Mz is applied to the multi-axis load cell according to the present invention The figure which shows the shape deformed using the analysis method.

As the torque Mz acts on the upper plate 112 as shown in FIG. 12, the torque Mz is transmitted to the respective pillars 118a, 118b, 118c, and 118d, and at the same time, the respective pillars 118a, 118b, 118c, and 118d. The shear deformation occurs in the tangential direction of the upper plate 112 (see FIG. 13).

When shear deformation occurs in each column 118a, 118b, 118c, and 118d by the torque Mz, eight strain gauges Mz1, which sense torque Mz attached to each column 118a, 118b, 118c, and 118d, are detected. ..., Mz8) detects this and outputs it as a signal, and the force Mz can be measured by the output signal.

The multi-axial load cell 100 according to the present invention formed as described above has only four pillars 118a, 118b, 118c, 118d constituting the body 110 and the lower plate 120 in three directions of force (Fx, Fy, Fz). And a sensing means for detecting torque in three directions (Mx, My, Mz) is attached, so the design is simple, and the design is simplified by reducing the dependent design variables so that the capacity setting according to the order and the setting of the axis to be detected To facilitate.

In addition, the multi-axis load cell 100 according to the present invention can significantly reduce the manufacturing cost because the structure is simple, it is possible to reduce the man-hour for circuit work as the configuration of the complex circuit is simplified.

In addition, since the multi-axis load cell 100 according to the present invention can simply configure the circuit, it is possible to reduce the errors in the production, anyone without a skilled worker can easily configure the circuit to enable stable production Let's do it.

The multi-axis load cell 100 as described above is not limited to the configuration and operation of the embodiments described above. The above embodiments may be configured such that various modifications may be made by selectively combining all or part of the embodiments.

100: multi-axis load cell 110: body
112: top plate 118a: first pillar
118b: second pillar 118c: third pillar
118d: fourth pillar 120: bottom plate
124: detection guide groove 126: slit ball
130: pedestal 132: step
140: case

Claims (10)

In the multi-axis load cell 100,
The multi-axis load cell 100,
The upper plate 112 and the lower plate 120 which is spaced apart from the lower plate 112 and bent and deformed by the load applied from the upper plate 112, and between the upper plate 112 and the lower plate 120 A body 110 connected to and having vertical first, second, third and fourth columns 118a, 118b, 118c, and 118d that are bent and sheared by a load applied from the top plate 112;
It is attached to the body 110 and detects the bending and shear strain of the body 110 and outputs it as a signal to the force in three directions (Fx, Fy, Fz) and torque in three directions (Mx, My, Mz) Sensing means for making measurements;
A pedestal 130 to which the lower plate 120 of the body 110 is fixed and fixed to a fixing part of a system on which the multi-axis load cell 100 is mounted; And
The body 110 is limited to the inside so as to surround and protect the body 110, but the upper plate 112 of the body 110 protrudes to be fixed to the load portion of the system and is fixed to the pedestal 130. Includes case 140,
The sensing means,
Eight strain gauges Fx1, ..., Fx8 for sensing the force Fx connected in a Wheatstone bridge form to form a first sensing circuit;
Eight strain gauges Fy1,..., Fy8 for sensing the force Fy connected in a Wheatstone bridge form to form a second sensing circuit;
32 strain gauges Fz1,..., Fz32 that sense the force Fz connected in a Wheatstone bridge form to form a sixth sensing circuit;
Eight strain gauges Mx1, ..., Mx8 for sensing the torque Mx connected in a Wheatstone bridge form to form a third sensing circuit;
Eight strain gauges My1, ..., My8 for sensing the torque My that are connected in a Wheatstone bridge form to form a fourth sensing circuit; And
Eight strain gauges (My1, ..., My8) for sensing the torque Mz that is connected in the form of a whistle bridge to form a fifth sensing circuit;
Four (Fx1, ..., Fx4) of the eight strain gauges (Fx1, ..., Fx8) for detecting the force Fx is attached to each corner side of the outer long side (W) of the first column (118a), The other four (Fx5, ..., Fx8) is attached to each corner side of the outer long side (W) of the third pillar (118c) facing the first pillar (118a),
Four (Fy1, ..., Fy4) of the eight strain gauges (Fy1, ..., Fy8) for detecting the force Fy is attached to each corner side of the outer long side (W) of the second column (118b), The other four (Fy5, ..., Fy8) is attached to each corner side of the outer long side (W) of the fourth pillar (118d) facing the second pillar (118b),
16 (Fz1, ..., Fz16) of the 32 strain gauges (Fz1, ..., Fz32) for detecting the force (Fz) is adjacent to the eight sides of the lower plate 120 to provide a flat octagonal shape It is attached to the upper surface of the lower plate 120, another 16 (Fz17, ..., Fz32) is attached to the lower surface of the lower plate 120 adjacent to the eight sides of the lower plate 120,
Two of the eight strain gauges Mx1, ..., Mx8 for sensing the torque Mx are two of the two Mx1, Mx2 for detecting the force Fx attached to the upper both sides edges of the first pillar 118a. The two strain gauges Fx3, which are attached between the strain gauges Fx1 and Fx2, and the other two Mx3 and Mx4 which sense the force Fx attached to both bottom edges of the first pillar 118a. Fx4) and another two (Mx5, Mx6) are attached between the two strain gauges (Fx5, Fx6) for detecting the force Fx attached to the upper both sides edge of the third pillar (118c) Another two (Mx7, Mx8) is attached between the two strain gauges (Fx7, Fx8) for detecting the force Fx attached to the lower both sides edge of the third pillar (118c),
Two of the eight strain gauges My1, ..., My8 for sensing the torque My are two strains for detecting the force Fy attached to both upper edges of the second pillar 118b. Two of the strain gauges Fy3 and Fy4 attached between the gauges Fy1 and Fy2 and the other two (My3 and My4) sense the force Fy attached to the lower edges of the second pillar 118b. ) And another two (My5, My6) are attached between the two strain gauges (Fy5, Fy6) for detecting the force Fy attached to the upper both sides corners of the fourth column (118d) Another two (My7, My8) is attached between the two strain gauges (Fy7, Fy8) for detecting the force Fy attached to the lower both sides edge of the fourth column (118d),
Two of the eight strain gauges My1, ..., My8 for detecting the torque Mz are Mz1 and Mx2 on the first column 118a, and another two Mz3 and Mx4 are on the second column ( 118b), another two (Mz5, Mx6) are attached to the third pillar (118c), another two (Mz7, Mx8) to the fourth pillar, the first, second, third And adjacently attached to the upper side of the first, second, third and fourth pillars 118a, 118b, 118c, 118d at the center of the outer long side W of the fourth pillars 118a, 118b, 118c, 118d. Multi-axis load cells.
The method according to claim 1,
The top plate 112 is provided in a horizontal disk shape,
The first through hole 114 is formed in the center of the upper plate 112,
The upper surface of the upper plate 112 is a multi-axis load cell is formed with a plurality of first connecting holes 116 to be connected to the load portion of the system via a bolt.
The method according to claim 1,
The first to fourth pillars 118a, 118b, 118c, and 118d are disposed to be symmetrically rotated 90 degrees along an arc of an imaginary circle C1 concentric with the upper plate 112.
Upper and lower ends of the first to fourth pillars 118a, 118b, 118c, and 118d are connected to a lower surface of the upper plate 112 and an upper surface of the lower plate 120, respectively.
Upper ends of the first to fourth pillars 118a, 118b, 118c, and 118d, lower surfaces of the upper plate 112, lower ends of the first to fourth pillars 118a, 118b, 118c, and 118d and lower plates ( The upper surface of 120 is a multi-axial load cell that is connected smoothly so that stress is not concentrated.
The method according to claim 3,
The first to fourth pillars 118a, 118b, 118c, and 118d respectively have two long sides W facing each other horizontally and two long sides W connecting two ends of the two long sides W horizontally. Have a square section with a short side (T),
The first to fourth pillars (118a, 118b, 118c, 118d) are any one of the long side (W) is disposed in the center of the imaginary circle (C1).
The method according to claim 1,
The lower plate 120 is provided in a flat octagonal shape having a second through hole 122 formed in a central portion thereof.
The lower plate 120 is formed with a plurality of slit holes 126,
The slit holes 126 are formed outside the first to fourth pillars 118a, 118b, 118c, and 118d connected to the lower plate 120, and at the same time, the first to fourth pillars 118a, 118b, 118c, 118d) is formed between the lower plate 120 and vertically,
Eight sides of the lower plate 120 is a multi-axis load cell is formed so that the sensing induction grooves 124 of the "∞" shape toward the center of the lower plate 120 is extended.
The method according to claim 5,
The slit holes 126 have an inequality shape that opens the mouth toward the center side of the lower plate 120 when the lower plate 120 is viewed in plan,
The detection guide grooves 124 extend only to the adjacent slit hole 126,
On the upper and lower surfaces of the lower plate facing the two convex portions and the two concave portions of each of the sensing guide grooves 124, the strain gauges Fz1, ..., Fz32 for sensing the force Fz of the sensing means. Multi-axis load cell with).
delete delete The method according to claim 1,
The lower plate 120 is formed with a plurality of bolt fastening holes 128 to be connected to the pedestal 130 via a bolt,
The upper surface of the pedestal 130 is formed to protrude stepped portion 132 at a position corresponding to the plurality of bolt fastening holes 128, the stepped portion 132 to the bolt fastening hole 128 Corresponding bolt fastening grooves 134 are formed,
The lower surface of the pedestal 130 is a multi-axis load cell in which a plurality of second connecting holes are formed to be connected to the fixing portion of the system via a bolt.
The method according to claim 1,
The case 140 is provided in a hollow housing shape, the side is closed and the lower part is opened, the upper portion is exposed hole 142 is formed to expose the upper plate 112 of the body 110 to protrude Provided,
A connector mounting hole 144 for guiding the first to sixth sensing circuits formed by the sensing means is formed at a side of the case 140.
The case 140 and the pedestal 130 is fixed via a bolt,
A fixing hole 146 is formed in the case 140 facing the outer circumferential surface of the pedestal 130, and the fixing shaft 148 is formed in the pedestal 130 to correspond to the fixing hole 146. Cell.

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