JPS6023687Y2 - Axle deflection detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an axle deflection detector that is applied to detect the load of a truck, for example, and detects deflection of the axle of a vehicle.

2. Description of the Related Art As a conventional means for detecting strain, an electric resistance wire strain meter is known in which a strain gauge is attached to an object to be detected with an adhesive.

For example, in a truck, the axle deflects depending on the weight of the cargo placed on the platform. Therefore, by detecting the deflection of the axle, the weight of the cargo on the platform can be determined.

In order to detect this deflection of the axle, it is conceivable to use an electrical resistance wire strain meter to detect the deflection of the axle. There is a risk that the strain gauge will peel off, causing errors, and the detection output will fluctuate due to temperature changes.

The purpose of this invention is to use a magnetostrictive strain detector to
An object of the present invention is to provide a deflection detector that can accurately detect deflection of an axle.

First, a magnetostrictive strain detector will be explained with reference to FIG.

A rod-shaped strain body 12 made of a magnetic material is bridged over one diameter of a ring-shaped body 11 made of, for example, a metal material and has elasticity and appropriate rigidity, and its both ends are fixed to the ring-shaped body 11.

An excitation coil 13 and a detection coil 14 are wound around the strain body 12 so as to cross each other at right angles S.

Attachment pieces 15 and 16 are respectively fixed to both ends of the ring-shaped body 11 in the extending direction of the flexure element 12, and attachment pieces 17.
18 are fixed respectively.

When an alternating current of, for example, 1000 Hz is passed through the excitation coil 13 from the alternating current signal source 19, a certain amount of magnetic flux is generated inside the strain body 12 in accordance with the inherent magnetic permeability of the material.

Therefore, due to the electromagnetic induction effect, the detection coil 14
A certain amount of alternating current flows at 0 Hz.

When tensile strain is generated in the flexure element 12 in this manner, its inherent magnetic permeability increases in accordance with the amount of strain (this is called the magnetostrictive effect). Even if a voltage is applied, the amount of magnetic flux flowing within the strain body 12 increases, and therefore the induced current in the detection coil 14 also increases.

Then, the amount of change in this induced current can be measured using an AC voltmeter 21, for example.
By measuring this, the magnitude of the force applied to the strain body 12 can be known.

Since the excitation coil 13 and the detection coil 14 are orthogonal to each other in this case, the magnetic flux generated in one coil 13 that passes only through the air is parallel to the other coil 14, and its component is the output of the coil 14. It is not.

However, since the magnetic flux generated by the coil 13 that passes through the strain body 12 has a component perpendicular to the coil 14,
An output corresponding to this is obtained from the coil 14.

The magnetic flux generated by the coil 13 that passes only through the air does not affect the output of the coil 14 even if the strain body 12 is subjected to strain.

Therefore, by arranging the coils 13 and 14 orthogonally, the output of the coil 14 can be significantly reduced with zero strain applied to the strain body 12, and the change in the output of the coil 14 due to the strain of the strain body 12 can be increased.

Mounting pieces 15 to 18 are fixed to the object to be detected, and a tensile force is applied to the object to connect the mounting pieces 15 and 16, so that the mounting pieces 1
When the distance between 5.16 becomes larger, the strain body 12
is pulled.

Conversely, when a compressive force is applied to the object to be detected in the direction that connects the mounting pieces 17 and 18, the distance between the mounting pieces 17 and 18 tends to become smaller, so that both ends of the strain body 12 at the orthogonal position of the ring-shaped body 11 The attachment part tries to spread to both sides, and the strain-generating body 12
is pulled.

Therefore, when measuring tension, use this strain detector with the mounting pieces 15 and 16 attached in the direction of the tensile force, and when measuring compression, use the mounting pieces 17 and 18 in the direction of the compression. Just install them side by side and use them.

This invention uses two such strain detectors to detect the deflection of the axle.

That is, in FIG. 2, for example, the left and right rear wheels 2 of the truck
The axle 3.24 is inserted and held within the axle frame 25.

Although not shown in the figure, a loading platform is supported on the axle frame 25 via supports 26 and 27.

In order to detect the deflection of the axle, a strain detector 28 shown in FIG.
The strain detectors 29 shown in FIG.
is installed by arranging the mounting pieces 15 and 16 in the axle extension direction.

When a load is placed on the carrier, the axle frame 25 deforms and bends according to the weight of the load, so the upper surface of the axle frame 25 is compressed and the lower surface is stretched.

This compressive force is detected by the strain detector 28, and the tensile force is detected by the strain detector 29.

Each output of these distortion detectors 28 and 29 is transmitted to a detector 31, for example.
．． 32 into a DC signal, the adder circuit 33 adds the signals, and the indicator 34 gives an indication.

The indicator 34 is provided at a position where the driver can see it.

If the outputs of the distortion detectors 28 and 29 are in the same phase, they may be added without being detected.

In this way, when using the same strain detector differentially,
This has the effect of canceling out errors due to temperature as follows.

When the truck starts traveling from a stopped state, the temperature of the axle frame 25 rises, the axle frame 25 thermally expands, and the expansion dimension is larger than that of the ring-shaped body 11 of the strain detector. Since tensile strain is being measured on the lower surface of the axle frame 25, the measured value will increase due to the difference in thermal expansion, but since compressive strain is being measured on the upper surface, the measured value will increase due to the difference in thermal expansion. The measured value decreases, and the error due to thermal expansion is just canceled out by the sum of both values.

The display displays the strain detected in this way at the front axle, the rear axle, and their total value.
Further, an adjustment section may be provided in the addition circuit 33, for example, to adjust the sensitivity for zero setting when the loading platform is empty or for setting the sensitivity by placing a load for verification.

According to the above-described axle deflection detector of this invention, it can be sufficiently firmly attached to the axle or related parts by the attachment pieces 15 to 18, and there is no fear that the attachment will come off, allowing accurate detection.

It also has the characteristic that no errors occur even when there are temperature fluctuations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an example of a magnetostrictive detector, and FIG. 2 is a configuration diagram showing an example of an axle deflection detector according to this invention. 11: Ring-shaped body, 12.: Strain body, 13: Excitation coil, 14: Detection coil, 15 to 18: Mounting piece, 25: Axle frame, 28, 29: Strain detector, 33: Addition circuit.

Claims (1)

[Scope of utility model registration request] The first and second sections are respectively placed on the upper and lower surfaces of the axle to be detected. A second strain detector is attached and these first . In the second strain detector, a magnetic rod-shaped strain body is bridged by a ring-shaped body having elasticity and appropriate rigidity, and both ends of the rod-shaped strain body are fixed. The first strain detector is configured by winding a coil and a detection coil, both ends of the ring-shaped body are fixed to the axle in a direction perpendicular to the extension direction of the strain-generating body, and the second strain detector is configured by winding a coil and a detection coil. is such that both ends of the ring-shaped body are fixed to the axle in the extending direction of the strain-generating body, and the first. An axle deflection detector configured such that the outputs of the detection coils of the second strain detector are added together by an adding means and taken out.