JPH0532691B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a sensor that detects force or moment, and more specifically, the present invention relates to a method for manufacturing a sensor that detects force or moment. Alternatively, the present invention relates to a method of manufacturing a sensor that senses a moment or both.

[Conventional technology]

In recent years, in order to control the work tools of industrial robots, the force and moment generated in the work tools when they come into contact with the workpiece are sensed and measured, and the robot drive mechanism is thereby controlled. method is being adopted. In such a control system, a sensor that senses force or moment is generally attached between the wrist of the robot arm and the work tool.
This sensor must accurately and continuously sense multi-component forces and moments.

Conventionally, a method using welding is known as a method of manufacturing this type of force-moment sensor. This method is roughly as follows.

That is, a circular plate member 1 and a shallow cylindrical cup member 2 with an open upper end are formed as shown in FIG. After bringing the mutually opposing end surfaces 3 and 4 into contact with each other, the two are joined and integrated by electron beam welding. A plurality of (four in the figure) slits 5 are formed at equal intervals in the circumferential direction on the side surface of the hollow flat cylindrical member thus produced, and plate portions 2a of the plate member 1 and the cup member 2 are formed. Four bridge portions 6 are formed to connect the two. As shown in FIG.
It is formed by individual milling into a substantially octagonal shape, and a hole 8 is formed in the center by drilling. Further, a center hole 9 passing through the cylindrical member is formed in the center of the cylindrical member by drilling using holes 1b and 2b provided at the center of the plate member 1 and the cup member 2.

However, in this conventional method, both the front and back surfaces of the bridge portion 6 formed are curved into a cylindrical shape, as shown in FIG.
For this reason, if a detector such as a strain gauge is used to extract the strain caused by the force or moment acting on this bridge part 6, it is extremely difficult to analyze it, and this is due to the force and moment sensing characteristics. was not necessarily satisfactory.

Furthermore, as a manufacturing method for this type of force-moment sensor, in addition to the welding method, there is also a known method in which a bridge portion similar to the above is formed by hollowing out the inside of a cylindrical block using a wire cut electric discharge machining method. ing. However, this method has the disadvantage that the processing cost is very high.

[Problem that the invention seeks to solve]

This invention was made in view of the above-mentioned circumstances, and its purpose is to provide a method for manufacturing a force-moment sensor that has good sensing characteristics at the bridge part and can be implemented easily and at low cost. Our goal is to provide the following.

[Means for solving problems]

In order to achieve the above object, this invention provides the following:
We have taken technical measures consisting of steps (a) to (d).

(a) two plate members 11 with projections 13 on one side, which projecting portions 13 form at least three flat outer surfaces 1 perpendicular to the plate portions 12;
3a and a means for positioning the bridge plate 17.

(b) A step of forming the same number of flat bridge plates 17 as the flat outer surfaces 13a of the plate member 11.

(c) Bringing the bridging plate 17 into contact with the flat outer surfaces 13a of both the plate members 11 and positioning them by the positioning means, so that the bridging plate 17 is moved through the bridging plate 17. The process of connecting.

(d) A step of joining and fixing the bridge plate 17 and both plate members 11 by welding.

[Effect]

According to the above technical means, both the plate member 11 and the bridge plate 17 have shapes that can be easily machined with a flat end mill or the like, and the bridge plate 17 can be positioned on the plate member 11. , these assembly operations can be easily performed.

Further, since the bridge portion is formed by using the flat bridge plate 17 as is, the strain generating portion can be formed into a flat plate shape.

〔Example〕

An embodiment of the method of the present invention will be described below with reference to the accompanying drawings.

First, two plate members 11 as shown in FIGS. 1 and 2 are formed. These can usually be easily obtained by milling a metal material such as an aluminum alloy with a flat end mill.

This plate member 11 has a protrusion 13 formed on one side of a disk-shaped plate portion 12.
This protruding part 13 has a shape like a square plate with rounded corners stacked on the plate part 12, and has four parts.
A positioning notch 14 having the same height as the end surface 12a of the plate portion 12 is formed in the center of each side surface. A bridge plate, which will be described later, is inserted into this notch 14 to position it, so it is formed to match the width and thickness of the bridge plate. Each notch 14 is formed with a flat outer surface 13a perpendicular to the plate portion 12, and adjacent thereto, a shallow groove 15 is formed in the protrusion 13. This groove is for storing welding metal when fixing the bridge plate by welding.

The plate member 11 is further provided with a hole 16 at the center thereof that passes through the plate member 11 in the central axis direction.

The next step is to remove the two plate members 11 mentioned above.
This is to join them with a bridge plate 17 interposed therebetween. This is done as follows. That is, first, the protrusion 13 of one plate member 11
A rectangular flat bridge plate 17 is fitted into the notch 14 with the plate facing upward. At this time,
The lower surface of the bridge plate 17 is the plate part 1
2, and its left and right side surfaces are in contact with the left and right side surfaces of the notch 14, respectively. The inner surface of the bridge plate 17 is in contact with the flat outer surface 13a. A state in which four bridge plates 17 are fitted into each notch 14 is shown in FIG. In addition, bridge plate 17
The plate member 11 can also be made of the same material as the plate member 11.

Next, while maintaining the state shown in FIG. 3, place the other plate member 11 on the bridge plate 17 with the protrusion 13 facing downward, and
Insert the upper end of each bridge plate 17 in the same manner as above. In this way, as shown in FIG. 4, when the two plate members 11 are concentrically connected by the four bridge plates 17, there is a space between the protrusions 13 of the upper and lower plate members 11. A space 18 is formed.

Subsequently, in order to fix each bridge plate 17 to the upper and lower plate members 11, welding is performed using a suitable jig while maintaining the above state. This welding is preferably electron beam welding. During welding, the bridge plate 17 is attached to the plate member 11.
At this time, the welding metal 19 can be stored in the elongated groove 15 provided in the protrusion 13 of the plate member 11, so the welding metal 19 can be simply welded along the periphery of the bridge plate 17. It is possible to increase the strength of welding compared to when welding. In this way, the force-moment sensor blank is completed.

This semi-finished product is milled or drilled using conventionally known methods to produce a completed sensor as shown in FIG. That is, the bridge plate 17 is milled so that four corners are cut off diagonally at the upper and lower ends, that is, the ends connected to the upper and lower plate members 11, so that the bridge plate 17 has a substantially octagonal shape. A hole 20 is formed in the center of the bridge plate 17 by drilling, passing through it in the central axis direction.

In addition, at the center of the upper and lower plate members 11, a through hole 21 is formed by drilling, using the hole 16 provided therein, to penetrate through both plate members 11 and extend in the direction of their central axis.

When processed as described above, the bridge portion formed by the bridge plate 17 has a flat surface not only on the outer surface but also on the inner surface, so that the strain-generating portion can be formed on a flat surface.

In this embodiment, four flat outer surfaces 13a are formed on the protrusion 13, but the present invention can be implemented with at least three. Furthermore, in order to improve the sensing performance, it is preferable that the flat outer surfaces 13a are all the same, and that the cross-sectional shape of the solid formed by connecting the extended surfaces of the outer surfaces 13a is a regular polygon. preferable.

〔Effect of the invention〕

Since the present invention has the above-described configuration, the bridge portion has a flat plate shape, and therefore the strain generating portion can have a flat plate shape. For this reason,
This has the effect that the sensing characteristics of the bridge portion become linear and very good.

In addition, since the plate member 11 and the bridge plate 17 are joined by welding, this invention can be implemented at low cost, and both the plate member 11 and the bridge plate 17 can be assembled using a flat end mill or the like. Since it can be easily processed, it has the effect of being easy to implement.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of a plate member used in the method of the present invention. FIG. 2 is a half-sectional front view of the same. FIG. 3 is a plan view of four bridge plates fixed to one plate member. FIG. 4 is a half-sectional front view of a blank force-moment sensor manufactured by fixing a bridge plate between upper and lower plate members. Figure 5 shows the force-moment curve produced using the blank shown in Figure 4.
FIG. 3 is a front half-sectional view of the sensor. Figures 6 to 8 are
FIG. 6 is a cross-sectional view showing a state before the plate member and the cup member are joined together, and FIG. 7 is a half-sectional front view of a completed force-moment sensor. FIG. 8 is a plan view of the same. 11...Plate member, 12...Plate part,
12a... End surface, 13... Protrusion, 13a... Flat outer surface, 14... Notch, 15... Groove, 1
6, 20... hole, 17... bridge plate,
18... Space, 19... Metal for welding, 21...
Through hole.

Claims (1)

[Scope of Claims] 1. Two plate members 11 each having a protrusion 13 on one side, the protrusion 13 forming the plate part 1.
at least three flat outer surfaces 13a perpendicular to 2;
and a step of forming a plate having a positioning means for the bridge plate 17; a step of forming the same number of flat bridge plates 17 as the flat outer surfaces 13a of the plate member 11; a step of bringing the plates 17 into contact with the flat outer surfaces 13a of both plate members 11 and connecting the plates 11 via the bridge plate 17; and the bridge plate 17 and both plate members 11. A method for manufacturing a force-moment sensor, comprising the step of joining and fixing the two by welding. 2. According to claim 1, the flat outer surface 13a and the bridge plate 17 are each formed in four pieces, and the outer surface 13a is arranged like a side surface of a regular square prism. Manufacturing method described. 3. The device according to claim 1 or 2, wherein the positioning means is a notch 14 formed on each side of the protrusion 13 and having a width approximately equal to the width of the bridge plate 17. Production method.