JP3348400B2 - A strain gauge that applies a load to a stress disk via a flexible load transmitting part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strain gauge type force meter (load cell) for applying a load to a stress disk via a flexible load transmitting portion.

[0002]

2. Description of the Related Art Cylindrical axial stress type dynamometers as shown in FIG. 4 are frequently used. 41 is an upper pressure plate, 42 is a stress cylinder portion, 43 is a lower pressure plate, 44 is a pressure receiving plate, 45 is an electric strain gauge, P ₁ is a load, L ₁ is the length of the stress cylinder portion 42,
δ ₁ is the amount of deflection, and t ₁ is the thickness of the stress cylindrical portion 42.

[0003]

Since this type of dynamometer utilizes axial stress, the height of the entire dynamometer cannot be reduced unnecessarily. In the case of a light load dynamometer (several hundred kgf or less), the output electricity of the electrostriction gauge 45 must be increased to a required voltage or more.
It is necessary to be 8000 kgf / cm ² . Thus, if for light load, the thickness t ₁ of the stress cylindrical portion 42 is required to be thin in a few hundredths 1mm~ tenths 1 mm.

[0004] This often causes breakage due to an unexpected impact or overload during handling or use of the dynamometer. Also, it is often difficult to fabricate and process a very thin cylindrical shape. The deflection against the axial load is very small (usually several hundredths of mm), and it is difficult to provide a mechanical limiter for this deflection. Almost no. An object of the present invention is to solve the above-mentioned problems by employing a stress disk.

[0005]

According to the present invention, a strain gauge type dynamometer of the type in which a load is applied to a first stress disk via a flexible load transmitting portion according to the present invention comprises a stress disk and one surface. The stress disk has a cylindrical load input portion and a flexible load output portion which project from the surface on the same axis as the stress disk and have different diameters and are flexible. The thickness of the load input section and the load output section is the stress circle.
It is configured to be sufficiently thin compared to the thickness of the plate,
The ratio of the bending stiffness of the load output portion to the bending stiffness of the stress disk is
It is 1/10 or less. Strain gauges are provided on the one surface and the other surface, respectively, concentrically with the stress disk. The other end of the load input unit is connected to the one-side pressure plate, and the load output unit is connected to the other-side pressure plate.

When a load is applied to the one-side pressure plate, the load is transmitted to one surface of the stress disk by flexing a cylindrical load input portion coaxial with the stress disk. Since the other surface of the stress disk has a diameter different from that of the load input portion and is supported by a cylindrical load output portion coaxial with the load input portion, the load also causes the stress disk to bend. This load also bends the load output portion and is finally transmitted to the other-side pressure plate. The
The thickness of the load input section and the load output section is determined by the thickness of the stress disk.
The load input section and the load output
The ratio of the bending stiffness of the part to the bending stiffness of the stress disk is 1/10 or more
Because it is below, the load input section and the load output section
The effect of the stress generated by deformation on the measured stress of the stress disk
The sound is minimal and accurate load measurement can be performed. The amount of deflection of the stress disk is electrically output by a strain gauge attached concentrically to both sides of the stress disk, and the load is measured. In this case, since the load is detected by the bending of the stress disk, the axial lengths of the load input unit and the load output unit do not need to be increased, and the axial length of the dynamometer can be shortened, that is, the dynamometer itself can be made compact.

A projecting flange provided on the one-side pressure plate,
A deflection limiting gear is provided between the deflection limiting device provided on the other side pressure plate.
A cap may be provided. In this case, the overload
If the surface side pressure plate tries to bend significantly, the protruding flange will bend.
The deflection is prevented by the restriction device, and the overload
Due to mechanical limitations, especially light load dynamometers (several hundred kgf
The safety for use and handling of the following is increased.

In the second stress disk according to the present invention, a flexible load is applied to the second stress disk.
Strain gauge type force that applies load via heavy transmission part
The meter is configured such that the load input unit and the load
The thickness of the output section is sufficiently thin compared to the thickness of the stress disk.
And the bending stiffness of the load input section and the load output section and
The ratio of the bending rigidity of the stress disk is 1/10 or less.
Configuration, and added a configuration related to the deflection limit gap to the requirements.
It is a thing. In the case of this second force meter, the load input / output unit
Can be expected by specifying the bending stiffness ratio of the disk
However, there is no excess of the one-side pressure plate secured by the configuration of claim 2.
The safety of the dynamometer by the prevention of large deflections is likewise ensured.

The stress disk, the load input section, and the load output
Part, the one-side pressure plate and the other-side pressure plate have an integral structure.
It may be. In this case, rotation against deformation due to load
Friction and hysteresis because there are no sliding parts
It can minimize errors and is suitable for long-term use.

[0010] The outer diameter of the load input section may be smaller than the inner diameter of the load output section. In this case, the bending of the stress disk is performed smoothly, and the load measurement becomes accurate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, the same reference numerals indicate the same or corresponding parts. FIG. 1 is a view for explaining a state in which stress is generated in the stress disk 1 when a concentric ring type load is applied to the stress disk 1 with simple peripheral support. When the lower surface of the stress disk 1 having the thickness h is supported on the circumference of the diameter 2a and a load P is applied to the upper surface in the area of the diameter 2b, the disk portion in this area receives uniform stress. σθ is the circumferential stress and σγ is the radial stress.

[0012]

(Equation 1) β₇… Coefficient (display) (0 to 1.0)

FIG. 2 shows a cross section of a specific example of a dynamometer (load cell) according to the present invention, wherein 1 is a stress disk. Reference numeral 2 denotes a load input portion, which protrudes from one surface 3 of the stress disk 1 coaxially with the stress disk 1 and has a flexible tubular shape. Reference numeral 4 denotes a load output portion which projects coaxially with the stress disk 1 from the other surface 5 of the stress disk 1 and has a flexible tubular shape. The load input unit 2 and the load output unit 4 have different diameters. Load input unit 2 and load
The thickness t of the heavy output portion 4 is sufficiently larger than the thickness T of the stress disk 1.
Bending rigidity of load input part 2 and load output part 4
Ratio (t / T) ³ between the flexibility and the bending rigidity of the stress disk 1 is 1/10
It is as follows.

Strain gauges 6 and 7 are provided on one surface 3 and the other surface 5 of the stress disk 1, respectively, concentrically with the stress disk 1.
The other end of the load input unit 2 continues to the pressing plate 8 on the one surface 3, and the other end of the load output unit 4 continues to the pressing plate 9 on the other surface 5.

When the load P is transmitted to the stress disk 1 by the cylindrical load input unit 2 and the load output unit 4, the stress disk 1 is bent, and the load P is measured by the electric output of the strain gauges 6 and 7.

In this case, since the load is detected by the deflection of the stress disk 1, the axial lengths of the load input unit 2 and the load output unit 3 do not need to be increased, and the axial length of the dynamometer is shortened. It is compacted.

In particular, even in the case of a dynamometer (load cell) having a light load (several hundred kgf or less), the thickness T of the stress disk 1 and the thickness of the load input portion 2 and the load output portion 4 are maintained without impairing the performance. The thickness t can be designed to be several mm or more. Therefore, against unexpected hits or overload during handling or use,
Sufficient security can be obtained. In addition, load input unit 2 and
And the stress generated by the deformation of the load output unit 4
Influence on constant stress is minimal, and more accurate load measurement
Can be.

In FIG . 3, a protruding flange provided on the one-side pressure plate 8 is shown.
And a deflection limiting device 12 provided on the other surface side pressing plate 9.
Is provided with a deflection limiting gap C. do this
When the overload is applied, the one-side pressure plate 8 tries to bend greatly.
Then, the protruding flange 11 is bent by the bending limiter 12.
Is prevented, and overload is mechanically limited.
Use and measure a light load (several hundred kgf or less)
Safety for handling is increased. Also, the axis of the stress disk 1
The direction deflection δ is much larger than the axial stress type,
mm, it is easy to design
2, the safety device is easily installed and stable safety
Can be used as a device.

From the specific example of the first dynamometer according to the present invention,
The thickness t of the heavy input output portions 2 and 3 and the ratio of the bending rigidity of both portions
Except for the configuration described above, the projecting flange 1 provided on the one-side pressure plate 8
1 and the deflection limiting device 12 provided on the other-side pressure plate 9
The configuration in which the deflection limiting gap C is provided is the
9 is a specific example of a second force meter according to the present invention. In this case, excluded
Although the function and effect of the configuration cannot be achieved, it is described in [0008].
As shown in FIG.
Can increase safety for use and handling
You.

Stress disk 1, load input unit 2, load output unit
4. The one-side pressure plate 8 and the other-side pressure plate 9 have an integral structure.
ing. In this way, the components are not deformed by the load.
Since there is no rotating or sliding part between the parts, friction error
And hysteresis error can be minimized, and for long-term use
Suitable.

The outer diameter of the load input section 2 is smaller than the inner diameter of the load output section 4. In this case, the bending of the stress disk 1 is performed smoothly, and the load measurement becomes accurate.

[0022]

According to the first dynamometer according to the present invention, the stress of the stress disk is evenly generated within the range of its diameter with respect to the concentric ring type load. And the strain gauge is easily bonded. Further, since the stress material is a disk, the total length of the force meter (load cell) can be shortened, and the size can be reduced. In addition, since the thickness of the load input section and the load output section receives only the axial stress with respect to the load, even if the thickness is sufficiently smaller than the thickness of the stress disk , the stress disk can maintain the strength capable of coping with the load. It can transmit the load <br/> heavy through, and bending rigidity ratio between the stress discs 1/10
The load input part and load output part change
Influence of Formed Stress on Measured Stress of Stress Disk
The amount is small and accurate load measurement can be performed.

According to the second aspect, the axial deflection of the stress disk.
Is a very large value (a few mm) compared to other types of dynamometers.
The protruding flange provided on the one-side pressure plate and the other-side pressure plate
A deflection limiting gap is provided between the device and the deflection limiting device.
This causes overload to be applied and the one-side pressure plate
When trying to bend, the projecting flange is
Is prevented, and overload is mechanically limited.
Use and measure a light load (several hundred kgf or less)
Safety for handling is increased.

According to the second dynamometer according to the third aspect of the present invention, the operation is performed by specifying the ratio of the bending rigidity of the disk of the load input / output unit.
Effect is not expected, but excessive bending of the pressure plate on one side is prevented.
The safety of the dynamometer by stopping is ensured.

According to claim 4, a stress disk, a load input.
Part, load output part, one side pressure plate and the other side pressure plate are integrated
Because of the structure, rotating parts and
There are no sliding parts and friction and hysteresis errors are minimized.
Can be reduced and suitable for long-term use.

According to the fifth aspect, since the outer diameter of the load input section is smaller than the inner diameter of the load output section, the bending of the stress disk is performed smoothly, and the load measurement becomes accurate.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a state in which a stress is generated on a disk when a concentric ring-type load is applied to the disk by simple peripheral support.

FIG. 2 is a cut-away side view showing a specific example of a strain gauge type dynamometer in which a load is applied to a stress disk via a flexible load transmitting portion according to the present invention in a state where a load is applied. .

FIG. 3 shows another specific example of a strain gauge type dynamometer for applying a load to a stress disk via a flexible load transmitting portion according to the present invention, and a partially cut side surface with an overload prevention device. FIG.

FIG. 4 is a cut-away side view of a conventional cylindrical type axial stress type force meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stress disk 2 Load input part 3 One surface 4 Load output part 5 Other surface 6 Strain gauge 7 Strain gauge 8 One surface side pressure plate 9 The other surface side pressure plate P Load T Thickness t Thickness δ Axial deflection 11 Projection flange 12 Bending limiter C Bending limit gap

Claims (5)

(57) [Claims] 1. A cylindrical member having a diameter different from each other and each having flexibility, protruding from one surface (3) and the other surface (5) of the stress disk (1) coaxially with the stress disk (1). It has a load input section (2) and a load output section (4), and has a load input section (2) and a load output section (4).
The thickness (t) is sufficiently thinner than the thickness (T) of the stress disk (1).
And the bending rigidity of the load input section (2) and the load output section (4).
(T / T) ³ between the elasticity and the bending stiffness of the stress disk (1) is 1/1
0, and strain gauges (6, 7) are provided on the one surface (3) and the other surface (5) concentrically with the stress disk (1), respectively, and the load input portion (2) The other end is connected to the one-side pressure plate (8), and the other end of the load output part (4) is connected to the other-side pressure plate (9). A strain gauge type force meter that applies a load through the load transmission section of 2. A projecting furan provided on the one-side pressure plate (8).
(11) and a deflection limiting device (12) provided on the other side pressure plate (9).
Wherein a deflection limiting gap (C) is provided between
2. A strain gauge type force meter that applies a load to the stress disk via a flexible load transmitting unit according to 1. 3. A cylindrical tube having a diameter different from each other and protruding coaxially with the stress disk (1) from one surface (3) and the other surface (5) of the stress disk (1). It has a load input part (2) and a load output part (4), and strain gauges (6, 7) are provided on the one surface (3) and the other surface (5) concentrically with the stress disk (1), respectively. The other end of the load input section (2) is connected to the one-side pressure plate (8), and the load output section
The other end of the (4) is followed the another surface side pressure plate (9), said one side
The projecting flange (11) provided on the pressure plate (8) and the other side pressure plate
The deflection limiting gap between the deflection limiting device (12) and (9)
A strain gauge type dynamometer for applying a load to a stress disk via a flexible load transmitting portion, wherein a stress disk is provided . 4. The stress disk (1), the load input section (2), the load output section (4), the one-side pressing plate (8), and the other-side pressing plate.
The strain gauge type dynamometer for applying a load to a stress disk via a flexible load transmitting portion according to claim 1 , wherein (9) has an integral structure. 5. An outer diameter of said load input section (2) is equal to said load output section.
One of claim 1 is smaller than the inner diameter of 4 (4)
A strain gauge type force meter for applying a load to the stress disk described in the above section via a flexible load transmitting portion.