JPH0450970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a load detection device that can detect loads with high accuracy.

[Conventional technology]

Detecting the load applied to each mechanical component constituting a machine is important in achieving desired control of the machine.

Conventionally, as a load detection device used for detecting such loads, Japanese Utility Model Application No. 57-46842,
The technology described in Japanese Patent Application Laid-Open No. 50-97376 (hereinafter referred to as
(referred to as "Prior Art 1 and Prior Art 2").

In prior art 1, a shear pin type load cell is provided as a load detection device for detecting the force acting between brackets constituting a force transmission member.
This shear pin type load cell consists of a load-bearing part that is placed between brackets and forms a columnar body that receives a load, and an insertion member that is inserted into a hole formed along the axial direction of this load-bearing part. .
This insertion member has a connecting part that connects with the load-bearing part at both ends and a central position, has a fixing part integrally with these connecting parts and has a dimension smaller than the dimension of the connecting part, and has a fixing part at the central position. One each is provided between a certain fixed part and a fixed part on one end side, and one each between a fixed part in the center position and a fixed part on the other end side, and the load-bearing part is It has a deformation sensitive part, that is, a sensor part, which deforms in response to the applied load and expands the strain. A strain gauge is attached to the sensor section.

In this prior art 1, when a load is applied to the joint portion located at the center of the load-bearing portion, the entire portion between the joint portions located at both ends deflects uniformly. The deflection at this time is the deflection due to bending,
This is a combination of deflection due to shear force. This deflection is magnified in the sensor section, detected by the strain gauge, and output as a signal. The applied load is calculated based on the signal value and the relational expression of deflection.

Furthermore, in Prior Art 2, a columnar body connecting a pair of bosses constituting a force transmission member and another boss arranged between these bosses, that is, a measuring pin is attached to both ends of the measuring pin and its axis. Two holes are formed in the center direction, and each of these holes is provided with an insertion member, that is, a load converter. The entire load transducer is formed in the shape of a bolt, has a hole passing through it along its axial direction, and has a deformation-sensitive part that deforms in response to the load, that is, an annular part, between the connecting part that connects to the measuring pin. It has a groove, and a strain gauge is attached to the inner peripheral surface corresponding to the annular groove.

In this prior art 2, although the load converter does not have a strain magnification function, the load converter uniformly bends and deforms in accordance with the load applied to the measurement pin, similar to the above-mentioned prior art 1. A signal corresponding to the deflection due to bending is output from the strain gauge, and the load applied to the measurement pin is determined according to that signal.

[Problem to be solved by the invention]

By the way, in both of the above-mentioned prior arts 1 and 2, the load is determined based on strain including strain due to bending deformation. In general, the magnitude of strain due to bending deformation varies depending on the location of the point of application of the load, as the form of bending deformation changes. It is not suitable for detecting a load on a force transmitting member that changes. For example, in Prior Art 1, if the point of application of the load is at a position shifted from the center position, the bending strain component of a magnitude different from the strain due to bending deformation when the point of application of the load is at the center position is the strain. The load value is detected by the gauge and is therefore different from the load value when the load application point is at the center position. This is related to conventional technology 2.
The same applies to

As described above, in the conventional techniques 1 and 2 described above, when detecting a load in a force transmission member where the point of application of the load, that is, the position at which the load is applied, can fluctuate, the error in the detected value is large. , there is a problem that the load detection accuracy decreases.

The present invention has been made in view of the above-mentioned actual situation in the prior art, and its purpose is to provide a load detection device that can determine the value of the load without being affected by changes in the point of application of the load. It is in.

[Means to solve the problem]

To achieve this objective, the present invention provides a columnar body disposed between force transmission members to receive a load, a hole formed at a neutral axis for bending deformation of this columnar body, and a columnar body inserted into the hole and provided at both ends. has a connecting portion that connects with the columnar body, a fixing portion that is connected to these bonding portions and has a dimension smaller than that of the bonding portion, and a fixing portion provided between these fixing portions that connects the columnar body with the columnar body. An insertion member having a deformation sensitive portion that deforms and expands strain in response to a load applied to a body, whose central axis substantially coincides with the neutral axis, and has at least two mutually orthogonal planes; signal converting means for converting the amount of deformation of the deformation sensitive part of the member into a signal and extracting only a strain component due to shear deformation occurring in at least one of the two mutually orthogonal planes of the deformation sensitive part; ,
The insertion member is arranged such that each of the mutually opposing end surfaces of the coupling portion is located within a region formed by the mutually opposing end surfaces of the force transmitting member.

[Effect]

As described above, the present invention is configured such that the central axis of the deformation sensitive part coincides with the neutral axis with respect to the bending deformation of the columnar body, so that the strain in the deformation sensitive part caused by bending deformation is basically It is minute,
Moreover, the fixed part and the deformation sensitive part are located between the end faces of the force transmission member, and the fixed part and the deformation sensitive part do not contact the columnar body and do not receive direct force. A stable and relatively large strain magnification factor is obtained regardless of variations in the position of the point of application, and furthermore, the signal converting means allows at least one of the two mutually orthogonal planes of the deformation sensitive section to be
Only the strain component due to shear deformation that occurs on two planes is extracted, and the load can be calculated according to the strain component due to this shear deformation, so that the strain component due to bending deformation is not involved in the calculation to calculate the load. Therefore, even if the position of the point of application of the load changes and the magnitude of strain due to bending deformation changes, the value of the load can be determined without being affected by the change.

〔Example〕

Hereinafter, the load detection device of the present invention will be explained based on the drawings.

FIG. 1 is a side view including a cross section showing an embodiment of the present invention, FIG. FIG. 3 is an explanatory view illustrating the mode of deformation occurring in the load detection device shown in FIG. 1, and FIG. 4 is a wiring diagram of a strain gauge provided in this embodiment.

In FIG. 1, 1 and 2 are force transmission members, that is, mechanical components, and 3 is these mechanical components 1,
This is a load detection device of the present invention which also serves as a pin connecting two. This load detection device 3 is inserted into, for example, a cylindrical columnar body 4, two holes 5 and 6 having a circular cross section formed at a neutral axis with respect to bending deformation of this columnar body 4, and these holes 5 and 6, for example. Insert members 7 and 8 made of metal are provided. In addition, the insertion member 7
is arranged between one arm of the machine component 1 and the machine component 2, that is, in one force transmission path, and the insert member 8 is arranged between the other arm of the machine component 1 and the machine component 2. , i.e., in a force transmission path different from the above-mentioned force transmission path. As shown in FIG. 2, the insert member 7 is
Coupling parts 9, 10 are provided at both ends to be coupled to the columnar body 4, that is, cylindrical coupling parts 9, 10 having approximately the same diameter as the hole 5.
A fixed part 9a having a diameter smaller than the diameter of
10a, and has thin plate-like deformation sensitive parts 11a, 11b, 11c, and 11d in the center that deform in response to the load applied to the columnar body 4 and magnify the strain. Similarly, the insertion member 8 also has coupling portions 12 and 13.
, fixed parts 12a, 13a, and deformation sensitive parts 14a, 1
4b, 14c, and 14d. In addition, the third
As illustrated in the figure, the area between the inner end faces of the coupling parts 9 and 10 of the insertion member 7 indicated by a distance L is between the end face of the machine component 1 indicated by a distance L' and the machine opposite to this end face. The length dimensions of the coupling parts 9, 10, fixing parts 9a, 10a, deformation sensitive parts 11a, 11b, 11c, 11d of this insertion member 7 are included in the area between the end face of the arm of the component member 2. ,
and the length dimension of the hole 5 are set. The deformation sensitive parts 11a to 11d and 14a to 14d described above have their symmetry axes almost aligned with the neutral axis for bending deformation, and are strained to a size that corresponds to their length, that is, the distance between the fixed parts. Expanding. In addition, the connecting parts 9, 10, 12, 1 of the insertion members 7, 8
3. Shrink fitting, welding, tightening with tapered screws,
It is coupled to the columnar body 4 by means such as fixing with adhesive.

Further, 15, 16, 17, and 18 are signal converting means, such as strain gauges, for converting the amount of deformation of the deformation sensitive parts 11a and 11c described above into signals. Among these, the strain gauges 15 and 16 are the deformation sensitive parts 11a,
11c, they are attached at positions that are perpendicular to each other, at an angle of approximately 45° to the axis of the columnar body 4, and symmetrical to the axis of the columnar body 4 in the vertical direction in the drawing. Note that the strain gauges 17 and 18 are attached to the back surfaces of the deformation sensitive parts 11a and 11c, as shown in FIG. 2b. That is, strain gauges 15 and 1
6 and strain gauges 17 and 18 are arranged at symmetrical positions with respect to the neutral axis for bending deformation of the columnar body 4. In addition, the strain gauge 17 is connected to the strain gauge 18 in a direction perpendicular to the strain gauge 16.
is attached in a direction perpendicular to the strain gauge 15. Similarly, 19, 20, 21, and 22 are strain gauges attached to the deformation sensitive parts 11b and 11d. Further, 15', 16', 17', and 18' are strain gauges similarly attached to the deformation sensitive parts 14a and 14c, and 19', 20', 21', and 22' are the strain gauges attached to the deformation sensitive parts 14a and 14c.
4b and 14d are strain gauges attached in the same manner. In addition, the above strain gauges 15 to 18,1
9 to 22, 15' to 18', and 19' to 22' are all attached to the central portions of the deformation sensitive parts 11a to 11d, 14a to 14d in the longitudinal direction (in the axial direction of the columnar body 4).

In addition, these strain gauges 15 to 18, 1
5'-18' and strain gauges 19-22,1
9' to 22' constitute a bridge illustrated in FIG. In FIG. 4, e _i is the input voltage, e ₁ is the output voltage from strain gauges 15 to 18, e' ₁ is the output voltage from strain gauges 15' to 18', e ₂ is the output voltage from strain gauges 19 to 22, _e'2 indicates the output voltage from the strain gauges 19-22'. 23 and 24 are strain gauges 15, respectively.
~18, 15'~18', or strain gauge 1
These lead wires 23 and 24 are connected to the insertion members 7 and 9 to 22, and 19' to 22', respectively.
It is inserted into the passages 25a, 25b, and 26 formed in the fixing parts and coupling parts 9, 10, and 13 of 8, and is led to the outside of the columnar body 4 through the hole 5 and the hole 50 that communicates the hole 5 and the hole 6. It will be destroyed.

51 and 52 are covers that close both ends of the columnar body 4. Also, the lead wire 2 is inside the cover 51.
A hole 53 through which the parts 3 and 24 can be inserted is formed.
54 is a connector to which the lead wires 23 and 24 are connected, and is supported by the cover 51. That is, the cover 51 also serves as a support member that supports the connector 54. 55 and 56 are covers 51 and 52, respectively.
This bolt is used to fasten the columnar body 4 to the columnar body 4. 57,5
Reference numerals 8 and 59 are O-rings that seal the inside of the load detection device 3.

Incidentally, FIG. 5 is a block diagram showing an example of a device connected to the load detection device 3 shown in FIG. 1. In FIG. 5, reference numeral 27 denotes an arithmetic unit, such as a microcomputer, which includes strain gauges 15 to 18, 15' to 18', 19 to 22, and 19'.
~22' output voltages e ₁ , e' ₁ , e ₂ , e' ₂ are input, and the strain gauge output voltages e ₁ ,
A storage device 29 that stores the correlation between e′ ₁ , e ₂ , e′ ₂ and the magnitude of force, and a CPU that performs logical judgments, calculations, etc. according to the signals input to the input device 28.
It consists of a (central processing unit) 30 and an output device 31 that outputs the results obtained by the CPU 30. Further, 32 is a display device connected to the output device 31 and consisting of a display or the like. These arithmetic device 27 and display device 32 constitute a signal processing means for processing the signal output by the load detection device 3. In general, this type of signal processing means is not limited to that shown in FIG. 5, and may take various forms.

In the embodiment configured as described above, suppose an unknown force is applied to the mechanical component 1 as shown in FIG.
Suppose that unknown forces W ₁ and W ₂ act on W ₃ and mechanical component 2, respectively, within the drawing plane of FIG. 1 (W ₃
= W ₁ + W ₂ ). At this time, for example, in the case of the side illustrated in _FIG . 4, a deformation amount δ within the range of distance L is generated. This deformation of the columnar body 4, and hence the deformation amount δ of the insertion member 7 within the range of distance L, is shown in FIG.
Deformation due to the shear force shown in FIG. 6 and deformation due to the bending moment shown in FIG. 6b occur.

In this case, in the columnar body 4, the amount of deformation δ during the distance L
occurs between the length dimension d in the deformation sensitive parts 11a, 11c, 14a, and 14c. That is, as shown in FIG.
Since the dimensions of the fixing parts 9a, 10a are set smaller than the diameter dimension of the fixing parts 9a, 10.
a is kept away from the wall surface of the hole 5, so that deformation due to receiving force from the wall surface of the hole 5 does not occur, and the deformation sensitive parts 11a, 11c
Only the parts are well deformed. At this time, a strain magnification rate of (L/d) times is obtained, and the force W ₁ is applied to the fixed parts a, 10a, the deformation sensitive parts 11a, 11c,
Since it does not act directly on 14a and 14c, the expansion ratio does not change regardless of fluctuations in the point of application of the force _W1 , and a stable strain expansion ratio can be obtained.
Note that the same applies to the insertion member 8.

In the case of deformation due to shear force, the same
As shown in Figure a, strain gauges 15, 15',
17, 17' are stretched, strain gauges 16, 16',
18, 18' shrink. Since these strain gauges 15 to 18 and ₁₅ ' to ₁₈ ' constitute a bridge as shown in _{FIG .} is output. At this time, as shown in FIG.
1b and 11d are also subjected to deflection deformation, and the amount of deformation is also δ. However, the deformation sensitive parts 11b and 11d have much lower rigidity with respect to deformation in this direction than the deformation sensitive parts 11a and 11c. Therefore, for the same amount of deformation δ, the deformation sensitive parts 11b and 11d are the same as the deformation sensitive parts 11a and 11c.
This produces much smaller distortions. In addition, the strain gauges 19 to 22 are connected to the deformation sensitive section 11.
If it is pasted at the center of the length direction (axis direction of the columnar body 4) of b and 11d, there will be no strain due to deflection deformation.
Therefore, almost no strain occurs in the strain gauges 19 to 22. The same thing can be said about the strain gauges 19' to 22' attached to the deformation sensitive parts 14b and 14d. After all, for the forces W ₁ and W ₂ in FIG. 1, the deformation sensitive parts 11a, 11c, 14a, and
Only the output voltages e ₁ and e ₁ of the strain gauges 15 to 18, 15' to 18' on c are output, and the strain gauges 19 to 22 on the deformation sensitive parts 11b, 11d, 14b, 14d perpendicular to the direction of force are output. , 19' to 22', the output voltages e ₂ and e' ₂ are hardly output.

Furthermore, for the force in the direction perpendicular to the drawing plane of FIG. 1, the output voltages (e ₂ ,
e′ ₂ ) is output, and strain gauges 15 to 18,
The output voltages e ₁ and e' ₁ of 15' to 18' are hardly output.

In the embodiment configured in this manner, it is possible to detect a force acting in any direction within a plane orthogonal to the axial direction of the columnar body 4.

In other words, if an unknown force W acts on a point P away from the axis of the columnar body 4 as shown in FIG. 7, this W is a component force Wx in the x direction and a component force in the y direction
It is divided into Wy and. The component force Wx deforms both side surfaces of the deformation sensitive parts 11b and 11d of the insertion member 7, and the amount of deformation is converted into a signal by the strain gauges 19-22. Further, the component force Wy deforms the upper and lower surfaces of the deformation sensitive parts 11a and 11c of the insertion member 7, and the amount of deformation is converted into a signal by the strain gauges 15-18. Wx and Wy are independently determined from the above-mentioned signals via a predetermined signal processing means. Also, by composing the obtained component forces Wx and Wy, the force W (=√ ² + ² ) and this force W
direction of action, for example, the angle θ with respect to the x-axis
(=tan ^-1 Wy/Wx) can be found.

Further, when the columnar body 4 receives a force as described above, a uniform shear strain is generated on the surface of the deformation sensitive portion. Therefore, there is no difference in output depending on where the gauge is attached. However, if the orientation of the gauge deviates from 45 degrees, the output will change, but even in that case, the output will be the cosine of the deviated angle, so a deviation of a few degrees will only result in extremely small output fluctuations. In this way, almost no output changes occur due to errors in the gage attachment position, so it is easy to make the rated outputs of the left and right detectors, the x and y directions, and the rated outputs of a large number of detectors the same. In addition, the deformation sensitive parts 11a to 11d,
Since a uniform shear strain is generated on the surfaces of 14a to 14d, even a strain gauge with a long gauge length can be used, and there are almost no restrictions on the size of the strain gauge used.

In addition, the deformation sensitive parts 11a to 11d, 14a to 1
4d is arranged along the neutral axis of bending deformation, the strain caused by the deformation due to the bending moment is extremely small. Furthermore, since the bridge is configured as shown in FIG. 4, when deforming due to this bending moment, the strain gauges 15, 15', 18, 1 are strained as shown in FIG.
8' is stretched, strain gauges 16, 16', 17, 1
7' is compressed, and therefore the elongation and contraction are canceled, and in the end, no signal is output due to deformation due to the bending moment. In other words, regardless of the deformation caused by the bending moment, that is, without being affected by any variation in the position of the point of action where W ₁ and W ₂ are applied, within the plane perpendicular to the axis of the columnar body 4. Only the shear strain component in any direction can be detected, and the forces W ₁ and W ₂ can be determined by calculating based on this shear strain component. In this way, in this example,
Even if the load, that is, the position where the forces W ₁ and W ₂ are applied, changes, stable detection values with small detection errors can be obtained, and the forces W ₁ and W ₂ can be detected with high precision. Also, the deformation sensitive parts 11a to 11d, 14a to 1
Since 4d is formed into a thin plate shape, its rigidity is smaller than that of the joint parts 9 and 10 at both ends, and the deformation of the entire load transmission part is reduced by the deformation sensitive parts 11a to 11d, 1.
4a to 14d, the distortion becomes large, and sufficient detection sensitivity can be ensured.

In addition, strain gauges 15-18, 15'-1
The output voltages e ₁ , e' ₁ , e 2 , e' ₂ outputted from the 8', 19-22, 19'- ₂₂ ' are, for example,
Processed in the device shown in the figure, the output voltage e ₁ ,
The force W ₁ corresponding to e' ₁ and the force W ₂ corresponding to the output voltages e ₂ and e' ₂ are determined, and if necessary, the force W obtained by calculating W ₁ + W ₂ = W ₃ in the CPU 30 is obtained. ₃
are determined, and these W ₁ , W ₂ , or W ₃ are output from the output device 31 of the arithmetic unit 27 to the display device 32 and displayed on the display device 32 .

Further, in the above embodiment, since the holes 5 and 6 into which the insertion members 7 and 8 are inserted are formed at the neutral axis with respect to the bending deformation of the columnar body 4, the holes 5 and 6 are
The decrease in the strength of the columnar body 4 caused by this can be suppressed to an almost negligible level. In other words, when the columnar body 4 receives a force, the maximum stress generated in the columnar body 4 is usually expressed as bending stress, so it is appropriate to evaluate the strength of the columnar body 4 by this bending stress, and this bending stress is generally 3 of the diameter of the columnar body 4
It becomes larger corresponding to the power. Therefore, the columnar body 4
In this embodiment, in which the outer diameter dimension, that is, the diameter is sufficiently ensured, sufficient strength can be ensured even if the holes 5 and 6 are formed at the neutral axis with respect to bending deformation.

In addition, in this embodiment, the strain gauge 15
~18,15'~18',19~22,19'~2
2' is placed in a closed state inside the columnar body 4 by the coupling parts 9, 10 or the coupling parts 12, 13 of the insertion members 7, 8, so that the distortion of the foreign matter outside the columnar body 4 is prevented. Gauge 15-18, 15'
-18', 19-22, and 19'-22' can be completely prevented from touching.

In this embodiment, as shown in FIG. 1, an insertion member 7 is provided in the force transmission path between the right arm of the member 2 and the member 1; An insertion member 8 is provided in the force transmission path between the For example, the position of the point of action is at the center of the columnar body 4, or at 1/1 of the total length from the right end
If the position is determined in advance, such as in position 3, the insertion member may be provided only for one transmission route instead of providing the insertion member for each transmission route as described above. The desired load can be detected even if the

FIG. 8a is a perspective view showing another example of the insertion member provided in the embodiment described above, and FIG. 8b is a sectional view showing the deformation sensitive portion of the insertion member shown in FIG. 8a.

In place of the insertion members 7 and 8 shown in FIGS. 1 and 2, an insertion member 33 shown in FIGS. 8a and 8b may be provided. Insert member 3 shown in FIGS. 8a and 8b
3 is a fixed part 34a, which is connected to the columnar body 4 and has joint parts 34 and 35 at both ends, and which is connected to these joint parts 34 and 35 and has a diameter smaller than the diameter of the joint parts 34 and 35; 35a, and a deformation sensitive part 38 in the center, which is made up of thin plate parts 36 and 37 that are connected to these fixing parts 34a and 35a and arranged orthogonally to each other. Note that 40 is a passage formed in the joint 34 through which a lead wire connected to the strain gauge can be inserted. The device including the insertion member 33 having the deformation sensitive portion 38 configured in this manner can also independently detect shear forces in two directions, the x direction and the y direction.

9, 10, 11, 12, 13, and 14 are explanatory diagrams showing further examples of the insertion member provided in the above embodiment, respectively, and FIG. 9a, FIG. 10a,
Figure 11a, Figure 12a, Figure 13a, Figure 14a are front views, Figure 9b, Figure 10b, Figure 11b, Figure 12b, Figure 13b, Figure 14. Figure b is a sectional view showing each deformation sensitive part.

In place of the insert members 7, 8 shown in FIGS. 1 and 2, the insert members shown in FIGS. 9a, b to 14 a, b may be provided. The insertion member shown in FIGS. 9a and 9b has a deformation sensitive part 60 in which orthogonal thin plate parts are connected to each other, and the insertion member shown in FIGS.
The insertion member shown in FIG.
The insertion member shown in Figures 1a and b cannot be inserted into the square hole 6.
The insertion member shown in FIGS. 12a and 12b is formed by making an impenetrable round hole 64. The insertion member shown in FIG. The insertion member shown in Figures a and b has a fixing part 70 and a deformation sensitive part 71 formed at the same time by providing a hole 69 that cannot be penetrated in the axial direction. Among these insertion members, the deformation sensitive parts shown in FIGS. 12, 13, and 14 are particularly easy to manufacture.

Although strain gauges are used as an example of signal conversion means in the above-described embodiments, the present invention is not limited to this. You can also.

Moreover, although the columnar body 4 is formed in a cylindrical shape in the above example, the present invention is not limited to this, and the columnar body 4 can take various shapes including a prismatic shape.

〔Effect of the invention〕

Since the load detection device of the present invention is configured as described above, it is possible to basically minimize the strain in the deformation sensitive part that occurs due to bending deformation, and also to minimize the strain at the point of application of the load. A stable and relatively large strain magnification factor can be obtained regardless of fluctuations, and the strain component due to bending deformation is not involved in the calculation of the load as in the conventional method.
Therefore, even if the position of the load application point changes and the magnitude of strain due to bending deformation changes, the load acts in at least one direction within the plane orthogonal to the axial direction of the columnar body without being affected by it. Therefore, it is possible to reduce the detection error when detecting a load in a force transmitting member where the load position can fluctuate, and it has the effect of obtaining higher load detection accuracy than conventional methods. be.

[Brief explanation of the drawing]

Fig. 1 is a side view including a cross section showing one embodiment of the load detection device of the present invention, Fig. 2a is a perspective view showing an insertion member provided in this embodiment, and Fig. 2b is the same as Fig. 2a. 3 is an explanatory diagram illustrating the mode of deformation that occurs in the load detection device shown in FIG. 1, and FIG. 4 is a wiring diagram of a strain gauge provided in this embodiment. , FIG. 5 is a block diagram showing an example of a device connected to the load detection device shown in FIG. 1, and FIGS.
FIG. 6A is an explanatory diagram illustrating the basic form of deformation that occurs in the load detection device shown in FIG. The figure is an explanatory diagram illustrating the force acting on the load detection device shown in Figure 1,
FIG. 8a is a perspective view showing another example of the insertion member;
FIG. 9b is a sectional view showing the deformation sensitive part of the insertion member shown in FIG. 8a, and FIGS. Figure 11a, Figure 12a, Figure 13a, 1st
Figure 4a is a front view, Figures 9b, 10b, 11
FIG. b, FIG. 12 b, FIG. 13 b, and FIG. 14 b are sectional views showing the deformation sensitive portion, respectively. 3... Load detection device, 4... Column body, 5, 6,
50, 53... hole, 7, 8, 33... insertion member,
9, 10, 12, 13, 34, 35... joint part,
11a-11d, 14a-14d, 38, 60,
63, 65, 68, 71...deformation sensitive section, 15,
16, 17, 18, 19, 20, 21, 22, 1
5', 16', 17', 18', 19', 20', 2
1', 22'...Strain gauge (signal conversion means),
23, 24, 40...Lead wire, 25a, 25
b, 26...Aisle, 36, 37, 41, 42, 4
3, 44, 45... Thin wall part, 51, 52... Cover, 54... Connector, 55, 56... Bolt,
57, 58, 59...O-ring.

Claims (1)

[Claims] 1. A columnar body placed between force transmission members to receive a load, a hole formed at a neutral axis for bending deformation of the columnar body, and a columnar body inserted into the hole and having the above columnar body at both ends. It has joint parts to be joined, and has a fixed part connected to these joint parts and having dimensions smaller than the dimensions of the joint part, and is provided between these fixed parts and applies a load to the columnar body. an insertion member having a deformation sensitive portion that expands strain by deforming in response to the above, a center axis of which substantially coincides with the neutral axis, and having at least two mutually orthogonal planes; a signal converting means for converting the amount of deformation of the part into a signal and extracting only a strain component due to shear deformation occurring in at least one of the two mutually orthogonal planes of the deformation sensitive part, and transmitting the force. such that each of the mutually opposing end surfaces of the coupling portion is located within a region formed by the mutually opposing end surfaces of the member,
A load detection device characterized in that the insertion member described above is arranged. 2. The load detection device according to claim 1, wherein the deformation sensitive part has a smaller size than the fixed part. 3. The load detection according to claim 1, characterized in that the deformation sensitive part is made up of thin parts that are substantially parallel to the neutral axis and orthogonal to each other, and a signal conversion means is arranged in each of these thin parts. Device. 4. The load detection device according to claim 1, wherein the signal conversion means is a strain gauge. 5. The load detection device according to claim 4, wherein the coupling portion has a passage through which a lead wire connected to the strain gauge can be inserted. 6. The load detection device according to claim 5, wherein the columnar body has a support member that supports a connector to which a lead wire is connected.