JPH0516091A - Robot force detector - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to reduce the size of a robot force detector provided in a small robot applied to mounting electronic components or assembling mechanical components. [Structure] Strain elements 24a to 24c and strain elements 24a to 24c
and the case (2
5) in which the force generated between the drive shaft 21 and the hand 22 is detected as the amount of strain of the flexure elements 24a to 24c, the flexure element fixing member 23 is attached to the drive axis 2 of the robot.
Insertion hole 31 extending in the axial direction of 1 and into which the drive shaft 21 is inserted
The first screw 33 for forming the first mounting portion 27 in which is formed and fixing the flexure element fixing member 23 to the drive shaft 21.
Is screwed to the first mounting portion 27 in the radial direction of the drive shaft 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force detector for robots, and more particularly to a force detector for robots provided in a small robot applied to mounting electronic parts and assembling mechanical parts.

[0002] In order to improve productivity, there is an increasing demand for automating operations such as mounting electronic components and assembling mechanical components, which conventionally depend on human hands.

In order to realize this, introduction of a robot is effective. However, in mounting and assembling work, there is a work of contacting the parts such as gripping each part,
It is necessary to control this contact force to an appropriate strength. Also,
In this type of work, it is necessary to make the size of the robot as small as possible because the position where the robot is arranged cannot be set large.

Therefore, it is desired to realize a small-sized robot force detector for detecting the contact force.

[0005]

2. Description of the Related Art FIG. 5 shows an example of a conventional robot force detector. The force detector for robot 1 shown in FIG. 1 has a configuration in which a case 3 is provided with a flexure element group 3 and a flexure element fixing member 4.

This robot force detector 1 is arranged between a drive shaft 5 and a hand 6 of a robot, and one end of a strain-flexing body fixing member 4 is fixed to the drive shaft 5 to generate a strain-generating body. One end of the group 3 is fixed to the hand 6. Further, the other end of the strain generating element group 3 is fixed to the other end of the strain generating element fixing member 4.
Therefore, in a state in which the robot force detector 1 is attached, the drive shaft 5, the flexure element fixing member 4, the flexure element 3, and the hand 6 are sequentially arranged in the axial direction of the drive axis 5 from the robot side. Becomes

The flexure element group 3 is composed of a plurality of flexure elements 3a. Each flexure element 3a is supported by the flexure element fixing member 4 so as to be displaceable in various directions, and each flexure element 3a is supported. A strain gauge (not shown) is arranged on the body 3a.

When an external force is applied to the hand 6 and the hand 6 is displaced,
Since the drive shaft 5 of the robot is fixed, a strain corresponding to this displacement occurs in each flexure element 3a as the hand 6 is displaced. The strain gauges provided in each strain element 3a are connected to a force detection processing device (not shown), and this force detection processing device performs analysis processing based on the signal supplied from each strain element 3a. The external force applied to the hand 6 is obtained.

Here, paying attention to the structure in which the robot force detector 1 is fixed to the drive shaft 5 of the robot, the mechanism for attaching the robot force detector 1 directly to the drive shaft 5 of the robot has not been provided in the related art. The robot force detector 1 was fixed to the drive shaft 5 by using the flange 7 for.

The flange 7 is composed of a cylindrical portion 7a and a disc-shaped portion 7b. The cylindrical portion 7a is formed with a fitting hole 7c into which the drive shaft 5 is fitted, and the disc-shaped portion. An insertion hole 7d into which the screw 8 is inserted is formed in 7b.

Therefore, the drive shaft 5 of the robot is inserted into the cylindrical portion 7a and fixed by the screw 9, and the disk-shaped portion 7b.
Is brought into contact with the bottom plate 2a of the case 2 and fixed with screws 8 (a screw hole is formed in the bottom plate 2a),
The robot force detector 1 is configured to be fixed to the drive shaft 5.

In order to fix the flexure element fixing member 4 to the case 2, the insertion hole 4 formed in the flexure element fixing member 4 is used.
A structure is adopted in which the screw 10 is inserted into a and is fixed by being screwed into a screw hole formed in the bottom plate 2a.

[0013]

As described above, a robot applied to mounting electronic parts or assembling mechanical parts needs to be as small as possible because the robot cannot be arranged at a large position. is there. In particular, it is important to reduce the size of the drive shaft 5 in the axial direction (the direction indicated by arrow X in the figure) from the viewpoint of preventing interference with other components arranged near the robot.

However, since the conventional robot force detector 1 requires the flange 7 to fix the force detector 1 to the drive shaft 5, the thickness of the disk-shaped portion 7b (arrow t in the figure).
There is a problem in that the length of the drive shaft 5 in the axial direction X becomes longer, and the miniaturization of the robot force detector 1 is hindered.

Further, in the conventional configuration, when fixing the robot force detector 1 to the disk-shaped portion 7b, it is necessary to screw the screw 8 to the bottom plate 2a of the case 2, and the flexure element fixing member 4 is fixed to the case 2. Also when fixing, it is necessary to screw the screw 10 to the bottom plate 2a. At this time, the direction in which the screws 8 and 10 are screwed is the axial direction X of the drive shaft 5.

Therefore, when the screws 8 and 10 are screwed to the length of the screw hole formed in the bottom plate 2a, the robot force detector 1 and the strain element fixing member 4 are surely screwed. In order to obtain a sufficient length, it is necessary to set the thickness of the bottom plate 2a to be thick in the axial direction X of the drive shaft 5, and this also increases the length of the drive shaft 5 in the axial direction X, and the force detection for the robot is detected. There is a problem that the miniaturization of the container 1 is hindered.

Further, in the conventional structure, since the flange 7 is required separately from the robot force detector 1, there is a problem that the number of parts is increased and the cost is increased.

The present invention has been made in view of the above points, and an object of the present invention is to provide a force detector for a robot which can be downsized.

[0019]

In order to solve the above problems, according to the present invention, a plurality of flexure elements, a flexure element fixing member to which the flexure elements are attached, a flexure element and a flexure element fixation. A case disposed so as to surround the member, by fixing the strain-flexing body fixing member to the drive shaft of the robot, and fixing the strain-flexing body to the hand, between the drive shaft and the hand. In a robot force detector for detecting a generated force as a strain amount of the strain generating body, the strain generating body fixing member is provided with an insertion hole extending in the axial direction of the drive shaft and into which the drive shaft is inserted. No. 1 mounting part is formed, and a first screw for fixing the strain-flexing body fixing member to the drive shaft is screwed into the first mounting part in the radial direction of the drive shaft. To do.

Further, the case is provided with a second mounting portion extending in the axial direction of the drive shaft and having a stepped insertion hole for inserting the first mounting portion to a predetermined position.
A second screw for fixing the case to the first mounting portion may be screwed to the second mounting portion in the radial direction of the drive shaft.

[0021]

According to the robot force detector having the above structure, the robot force detector is attached to the drive shaft by fixing the drive shaft to the first mounting portion formed on the flexure element fixing member. Since it is not necessary to provide a flange between the drive shaft and the robot force detector as in the conventional case, and the robot force detector can be directly attached to the drive shaft, the robot force detector can be downsized.

Further, since the screw is configured to be screwed in the radial direction, not in the axial direction of the drive shaft, the dimension of the robot force detector in the axial direction of the drive shaft is lengthened by using the screw. There is no.

Furthermore, since the case is fixed to the drive shaft by attaching the second mounting portion formed on the case to the first mounting portion, it is not necessary to provide a flange when fixing the case, and the robot can be fixed. The utility detector can be miniaturized.

[0024]

EXAMPLES Next, examples of the present invention will be described. Figure 1
FIG. 3 is a partial cutaway view showing a robot force detector 20 according to an embodiment of the present invention.

In the figure, reference numeral 21 is a drive shaft of the robot, and the robot force detector 20 is attached to the drive shaft 21. In addition, the drive shaft 2 of the robot force detector 20
The hand 22 is attached to the side different from the attachment side to 1. For example, when the robot is applied to mount electronic components, the hand 22 is a portion that directly contacts the electronic components and performs mounting processing.

The robot force detector 20 is composed of a flexure element fixing member 23, a flexure element group 24, and a case 25. In addition, the robot force detector 20 is attached from the robot side to the drive shaft 21 and the flexure element fixing member 2 in the attached state.
3, a flexure element group 24 and a hand 22 are sequentially arranged in the axial direction of the drive shaft 21.

FIG. 2 shows the flexure element fixing member 23 in an enlarged manner. The flexure element fixing member 23 is configured to also function as a flexure element that detects strain, and as shown in the figure, a cylindrical mounting portion 27 is provided at the center of a disk-shaped flexure element portion 26.
Is formed. A screw hole 29 into which a screw 28 for fixing the strain body group 24 is screwed is formed at a predetermined position on the outer circumference of the strain body portion 26. In addition, a slit 30 is formed in a cross shape in the strain-flexing body portion 26, so that the strain can be easily detected.

The mounting portion 27 has an insertion hole 31 formed at the center thereof into which the drive shaft 21 is inserted, and a step portion 32 is formed at a position near the outer peripheral tip. Furthermore, the mounting part 2
A screw hole 34 into which a screw 33 for fixing the flexure element fixing member 23 to the drive shaft 21 is screwed is formed on the side portion of the device 7. The mounting portion 27 extends in the axial direction (indicated by arrow X in the drawing) of the drive shaft 21 in the mounted state. Also,
The screw hole 34 is formed in the radial direction of the drive shaft 21. Therefore, the screw 33 is screwed into the screw hole 34 from the side of the mounting portion 27. Further, a half-moon key portion 27a is formed on the outer peripheral portion of the mounting portion 27, and the half-moon key portion 27a and the screw hole 34 are formed at a position separated by 90 ° from the center of the insertion hole 31. There is.

Next, the flexure element group 24 will be described. The flexure element group 24 includes a plurality of (three in this embodiment) flexure elements 24.
a to 24c. In the following description, among the plurality of flexure elements 24a to 24c, the flexure element 24a arranged at the right end in the drawing to which the hand 22 is attached is representatively shown in an enlarged manner in FIG. To do.

The flexure element 24a is the flexure element fixing member 2 described above.
It has a structure similar to that of No. 3 and has a configuration in which a cylindrical fixing portion 36 to which the hand 22 is attached is formed in the center of a disk-shaped strain generating body portion 35. A through hole 37 through which the screw 28 penetrates is formed at a predetermined position on the outer circumference of the strain-flexing body portion 26, and a cross-shaped slit 38 is formed in the strain-flexing body portion 36 to facilitate strain detection. There is. Further, the fixing portion 36 is formed with an insertion hole 40 into which the shaft provided with the hand 22 is inserted and a screw hole 39, and a screw 41 (shown in FIG. 1) is inserted into the screw hole 39. The shaft provided with the hand 22 is fixed to the flexure element 24a by screwing.

Subsequently, the case 25 is shown in an enlarged manner in FIG. 4 and will be described below. The case 25 is a pair of case halves 2.
5a, 25b, and both case halves 2
Combination step portion 4 formed at the joint portion of 5a and 25b
They are integrated by fitting 2a and 42b.

A cylindrical mounting portion 43 is formed at the center of the case half 25a. As will be described later, the flexure element fixing member 2 is attached to the mounting portion 43 (referred to as a second mounting portion).
The mounting portion 27 formed on the 3 (referred to as a first mounting portion)
Is formed with a stepped insertion hole 44.

On the side of the second mounting portion 43, the first
A screw hole 46 into which a screw 45 (shown in FIG. 1) for fixing the case 25 to the mounting portion 27 is screwed, and a screw 33 in the first mounting portion 27 is loosely fitted. Insertion hole 4
7 are formed. The screw hole 46 and the loose fitting insertion hole 47.
Is formed at a position separated by 90 ° from the center of the loose fitting insertion hole 47. On the other hand, the case half 25b
A hole 48 through which the fixing portion 36 of the flexure element 24a is loosely fitted is formed in the central portion of the.

In order to assemble the robot force detector 20 composed of the above-mentioned components 23, 24, 25, the shaft (not shown) for attaching the hand 22 to the fixing portion 36 of the flexure element 24a is fixed with the screw 41. After being fixed, the plurality of flexure elements 24a to 24c are placed on the flexure element fixing member 23 in an overlapping manner, and fixed to the flexure element fixing member 23 by the screws 28 to fix the flexure element fixing member 23 and the flexure element. The group 24 is integrated.

Subsequently, the strain body group 24 is attached to the case half 25a.
The flexure element fixing member 23 to which is attached is attached. Specifically, the first mounting portion 27 formed on the flexure element fixing member 23 is inserted into the stepped insertion hole 44 formed in the second mounting portion 43. At the time of this insertion, the first mounting portion 27
By engaging the step portion 32 formed in the stepped portion formed in the stepped insertion hole 44, the case half 25a
Then, the flexure element fixing member 23 is positioned in the direction of the arrow X in the figure.

Subsequently, the screw hole 46 formed in the second mounting portion 43 is positioned in the half-moon key portion 27a formed in the first mounting portion 27, and then the screw 4 is screwed into the screw hole 46.
5, the case half 25a is fixed to the flexure body fixing member 23. Next, the case half 25a is attached to the other case half 25b, whereby the robot force detector 2
0 is formed. In the assembled state, a small gap is formed between the strain-flexing body group 24 and the case 25, and the plurality of strain-generating bodies 24a to 24c can be displaced in the case 25. ing.

The robot force detector 20 assembled as described above has the insertion hole 2 formed in the first mounting portion 27.
The drive shaft 21 of the robot is inserted into the robot 7, and the screw 33 is screwed into the screw hole 34 also formed in the first mounting portion 27, whereby the robot is fixed to the drive shaft 21. At this time, screw 3
3 is a loose fitting insertion hole 47 formed in the second mounting portion 43.
It is screwed into the screw hole 34 via. Next, the flexure element 24a
By attaching the hand 22 to the shaft attached to the fixing portion 36, the attachment state shown in FIG. 1 is obtained.

With the structure in which the robot force detector 20 is fixed to the drive shaft 21 as described above, the drive shaft 21 is fixed to the first mounting portion 27 formed on the flexure body fixing member 23 with the screw 34. As a result, the robot force detector 20 is attached to the drive shaft 21. That is, the robot force detector 20 can be directly attached to the drive shaft 21 without providing a flange between the drive shaft 21 and the robot force detector 20 as in the prior art. Therefore, the robot force detector 20 can be downsized by the amount of space required for the flange, which is conventionally required, and the number of parts can be reduced, so that the manufacturing process can be simplified and the product cost can be reduced.

Since the screw 34 is screwed in the radial direction, not in the axial direction of the drive shaft 21, the screw 34 is used to drive the robot force detector 20 in the drive axis direction (indicated by arrow X in the figure). The dimension in the (direction shown) does not become long. Further, by attaching the second mounting portion 43 formed on the case 25 to the first mounting portion 27, the case 25 is fixed to the drive shaft 21 via the flexure element fixing member 23, so that the case 25 is fixed. When doing so, it is not necessary to provide a flange, and the robot force detector 20 can be miniaturized.

[0040]

As described above, according to the present invention, since the flange which has been conventionally required is not required, it is possible to reduce the size of the robot force detector 20 in a state of being attached to the robot. Have.

[Brief description of drawings]

FIG. 1 is a partially cutaway cross-sectional view of a robot force detector according to an embodiment of the present invention.

FIG. 2 is a partial cutaway cross-sectional view for explaining a strain-flexing body fixing member that constitutes a robot force detector that is an embodiment of the present invention.

FIG. 3 is a partial cutaway cross-sectional view for explaining a flexure element that constitutes a robot force detector that is an embodiment of the present invention.

FIG. 4 is a partial cutaway cross-sectional view for explaining a case constituting the robot force detector according to the embodiment of the present invention.

FIG. 5 is a partially cutaway cross-sectional view showing an example of a conventional robot force detector.

[Explanation of symbols]

20 Robot force detector 21 Drive axis 22 hands 23 Strain element fixing member 24 Strain group 24a to 24c flexure element 25 cases 25a, 25b half case 26,35 flexure part 27 mounting part (first mounting part) 28, 33, 41, 45 screws 29,34,39,46 screw holes 30,38 slits 31,40 insertion hole 32 step 36 Fixed part 37 Through hole 42a, 42b Combination step part 43 mounting part (second mounting part) 44 Stepped insertion hole 47 loose fitting insertion hole

Claims (3)

[Claims] 1. A plurality of flexure elements (24a to 24c), a flexure element fixing member (23) to which the flexure elements (24a to 24c) are attached, the flexure elements (24a to 24c), and the flexure element (24a to 24c). And a case (25) arranged so as to surround the flexure element fixing member (23), and the flexure element fixing member (23).
Is fixed to the drive shaft (21) of the robot, and the flexure element (24
By fixing a to 24c) to the hand (22),
In a force detector for a robot that detects a force generated between the drive shaft (21) and the hand (22) as a strain amount of the strain generating bodies (24a to 24c), the strain generating body fixing member (23) includes: A first mounting portion (27) extending in the axial direction of the drive shaft (21) and having an insertion hole (31) into which the drive shaft (21) is inserted is formed, and the flexure element fixing member ( The first screw (33) for fixing 23) to the drive shaft (21) is screwed to the first mounting portion (27) in the radial direction of the drive shaft (21). A force detector for robots. 2. A stepped insertion hole (44) extending in the axial direction of the drive shaft (21) into the case (25) for inserting the first mounting portion (27) to a predetermined position.
And a second screw (45) for fixing the case (25) to the first mounting portion (27) is formed on the second mounting portion (43). The force detector for a robot according to claim 1, wherein the force detector (43) is screwed in the radial direction of the drive shaft (21). 3. The first mounting portion in the second mounting portion (43)
3. The robot force detection device according to claim 2, wherein an insertion hole (47) for inserting the first screw (33) in a loosely fitted state is formed at a position opposite to the position where the screw (33) is provided. vessel.