JPH06186094A - Detecting device for displacement and pressing force - Google Patents

Abstract

PURPOSE:To provide a detecting device for displacement and pressing forces, which is almost in no danger of being broken even with application of excess force, requires almost no calibration, causes little error in measurement and has a calibration range which can easily be changed. CONSTITUTION:A cylinder 3 is secured to a base 1 and a piston 5 is slidably provided inside the cylinder 3. A pressure sensor 13 is provided for measuring pressure within a first space 11 defined by the front side of the piston 5 and the cylinder 3. A portion 9 to be pressed is provided at the end portion of a rod 7 provided to the piston 5 and is exerted with a pressing force. A spring 19 is provided between the back of the cylinder 3 and the portion 9 to be pressed. The cylinder 3 is provided with a hole 15 and a cap 17 is provided to the hole 15. When a pressing force is applied to the portion 9 to be pressed, the piston 5 moves and the pressure within the first space 11 varies, and the pressure sensor 13 measures the pressure to detect the pressure fluctuation and the pressing force and displacement are detected from the pressure fluctuation. To change a calibration range, air is forced into and out of the hole 15 or the spring 19 is replaced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detecting device for detecting displacement and pressing force.

[0002]

2. Description of the Related Art Conventionally, there is a detecting device as shown in FIG. 2 for measuring the pressing force and the displacement when receiving the pressing force. This detection device includes a plate-shaped fixing portion 101,
The plate springs 103 and 105 are provided between the plate-shaped pressed portions 107, and the strain gauge 109 is attached to the plate spring 105. FIG. 3 is a side view of this detection device, showing a state where no pressing force is applied, and FIG. 4 shows a state where a pressing force is applied. As shown in FIGS. 3 and 4, the fixing portion 101 is fixed to the base 111, and when the pressing force F is applied to the pressed portion 107, the leaf springs 103 and 105 are deformed and the strain gauge 109 causes the leaf spring 105 to move. Deformation is detected, and pressing force and displacement are detected.

[0003]

However, such a detecting device has the following problems. (1) When the excessive pressing force is applied and the deformation of the leaf springs 103 and 105 exceeds the elastic region, the detection device may be destroyed.
(2) The work of attaching the strain gauge 109 is troublesome, and the amount of detection of the strain gauge 109 differs depending on the place of attachment, which requires complicated calibration. (3) When the force is released from the state in which the force is applied, it vibrates and becomes illegal.
(4) An error occurs in the measurement value depending on the position and direction of the force. (5) Since the measurement range depends on the elastic limits of the leaf springs 103 and 105, when changing the measurement range, the device must be newly made.

The present invention has been made in view of the above problems, and the object thereof is that there is almost no possibility of destruction even when an excessive force is applied, calibration is almost unnecessary, and a measurement error occurs. It is an object of the present invention to provide a displacement / pressing force detection device that is small in number and can easily change the measurement range.

[0005]

In order to achieve the above object, the present invention provides a cylinder fixed to the outside, a piston sliding in the cylinder, a piston rod receiving a force from the outside, and A displacement and pressing force detection device comprising a cylinder and a pressure sensor that measures the pressure in a first space formed by the piston. In the present invention, the pressing force includes a negative pressing force, that is, a force for pulling the piston rod.

[0006]

In the present invention, when a force is applied to the piston rod from the outside, the pressure in the space formed by the cylinder and the piston changes, and this pressure is measured by the pressure sensor to determine the pressing force and the displacement of the piston rod. To detect.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view of a cross section of a displacement and pressing force detection device according to an embodiment of the present invention. A cylindrical cylinder 3 is fixedly mounted on the base 1. A piston 5 is slidably provided in the cylinder 3. Piston 5 and rod 7
Is provided, and the pressing force F to be measured is applied to the pressed portion 9 at the end of the rod 7. The cylinder 3 is provided with a pressure sensor 13 that measures the pressure in the first space 11 formed by the front surface of the piston 5 and the cylinder 3. The cylinder 3 relating to the second space 12 formed by the back surface of the piston 5 and the cylinder 3 is provided with an air amount adjusting hole 15. Code 1
7 is a cap of the hole 15.

A spring 1 is provided between the rear surface of the cylinder 3 and the pressed portion 9.
9 is provided. When the pressing force is applied to the pressed portion 9, the spring 19 gives a force that opposes a part of the pressing force. When using this detection device, the cap 17
The hole 15 is closed by. When changing the measurement range of the pressing force, the cap 17 is removed, air is sent from the hole 15, and the piston 5 is moved a little to change the measurement range. The measurement range can be changed by replacing the spring 19 and changing the spring constant. In order to detect the pressing force and displacement with this detection device, the pressure-sensitive portion 9
Apply pressing force to. When a pressing force is applied to the pressed portion 9, the piston 5 moves and the pressure in the first space 11 changes. The pressure sensor 13 measures the pressure in the first space 11 to obtain a pressure fluctuation, and based on this pressure fluctuation, the pressing force and the displacement due to the pressing force are detected.

In the detection device according to the present embodiment, there is almost no possibility of breaking even if an excessive pressing force is applied, and if it breaks, the pressure sensor 13 will only break. In this case, the pressure sensor 15 must be replaced. Can be dealt with. In addition, since there is almost no need to perform calibration, and this detection device has only one direction of freedom in terms of the mechanism, there is little detection error. Furthermore, when a pressing force is applied in a direction other than the sliding direction of the piston 5, Only the force component in the sliding direction of the piston 5 can be separated and measured. Further, regarding the change of the measurement range, the cap 17 can be removed and the air can be taken in and out from the hole 15, or the spring 19 can be replaced to change the measurement range, so that the measurement range can be easily changed.

In this embodiment, it is possible to measure the pressing force including the negative pressing force. Further, a pressure sensor may be provided on the side of the second space 12 and a hole for adjusting the air amount may be provided in the first space 11.

[0011]

As described above in detail, according to the present invention, there is almost no danger of breaking even if an excessive force is applied,
Calibration is almost unnecessary, there are few measurement errors,
The measurement range can be changed easily.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a displacement and pressing force detection device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a conventional displacement and pressing force detection device.

FIG. 3 is a side view of a conventional displacement and pressing force detection device.

FIG. 4 is a side view of a conventional displacement and pressing force detection device.

[Explanation of symbols]

 1 ... Base 3 ... Cylinder 5 ... Piston 7 ... Rod 9 ... Pressure section 13 ... Pressure sensor 15 ... Hole 17 ... Cap 19 ... Spring

Claims (3)

[Claims] 1. A cylinder fixed to the outside, a piston that slides in the cylinder, a piston rod that receives a force from the outside, and a pressure in a first space formed by the cylinder and the piston is measured. And a displacement and pressing force detection device comprising: 2. The displacement and pressing force detecting device according to claim 1, further comprising a spring for urging the piston rod. 3. The displacement and pressing force detection device according to claim 1 or 2, wherein a hole for adjusting an air amount is provided in a part of the cylinder in a second space formed by the cylinder and the piston.