JP2003279428A - Torque detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a torque meter detects a detection torque together with an error portion superimposed thereon, generated by disorder of balance of a rocking part caused by generation of thermal expansion of a torque detection mechanism by a change of a surrounding temperature. <P>SOLUTION: Two torque arms are provided on the rocking part at an angle of about 90° with a rocking shaft. Load cells are disposed on each torque arm so that forces in the reverse direction are applied respectively to the rocking part, to thereby counterbalance the error portion caused by thermal displacement. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque detector for a dynamometer.

[0002]

2. Description of the Related Art FIG. 2 shows the structure of a conventional torque detecting device. Reference numeral 1 denotes a swing part of a dynamometer, and a torque arm 2 is fixed to the swing part 1 in the horizontal direction.
Reference numeral 3 is a swing shaft, and 4 is a hydraulic levitation unit, which levitationally supports the swing unit 1. Reference numeral 5 is a fixed base, and 6 is a load cell attached between the torque arm 2 and the fixed base 5. The device under test is connected to the rotating side of the dynamometer. For example, when the device under test is rotated, the dynamometer absorbs the power of the dynamometer to generate torque (= axial torque) on the stator, and the oscillating shaft 3
The oscillating portion 1 rotates about. Therefore, a force is applied to the load cell 6 in the compression direction or the tension direction, and the detected value can be detected as the axial torque generated by the dynamometer and can be taken out as an electric signal.

[0003]

Normally, the output of the load cell 6 is set to be 0 mV when the swinging portion 1 is in a balanced state. However, due to a change in the ambient temperature where the dynamometer is installed, the load cell and other parts of the torque detection mechanism change in the vertical direction in the drawing due to thermal expansion, etc., and the swinging part 1 connected to this torque detection mechanism also moves up and down. It fluctuates in the direction and the balance is lost.
The amount of this imbalance appears as the output of the load cell 6. The load cell 6 is intended to measure only the axial torque, but the balance is lost due to a change in the ambient temperature, and the force generated by the collapse is also measured, resulting in a large measurement error.

The present invention has been made to solve the above problems, and its object is to provide a torque detecting device capable of detecting a shaft torque with high accuracy even if the ambient temperature changes. Is intended to be provided.

[0005]

According to a first aspect of the present invention, a load cell is attached to a torque arm fixed to a swing part of a dynamometer, and the torque of a device under test is detected through the load cell. Two torque arms are arranged in the swing portion at positions substantially perpendicular to the swing axis of the dynamometer, and each torque arm operates in opposite directions with respect to the rotation of the swing portion. It is characterized in that a load cell is provided in the.

A second aspect of the present invention is characterized in that one of the two torque arms is provided so as to project in the horizontal direction with respect to the oscillating portion, and the other one is provided so as to project vertically below the oscillating portion. It is a thing.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. The same parts as those in FIG. Reference numeral 11 is a second torque arm, and the second torque arm is the first torque arm 2 and the swing shaft 3
Is arranged at a substantially right angle with respect to, and in the downward vertical direction with respect to the swing shaft. In this torque arm 11,
One end of the second load cell 12 is connected and the other end of the second load cell 12 is fixed to the first load cell 6 side.

That is, the first and second load cells 6 and 1
2 is disposed at a position in which the detection modes are opposite to each other so that when one of the swing portions 1 is in a compressed state with respect to the rotation, the other is in a pulled state.

In the dynamometer having the above-described structure, when the DUT connected to the dynamometer is rotated, the dynamometer absorbs the power of the dynamometer to generate torque in the stator, so that the swing shaft 3 is rotated. The rocking | fluctuation part 1 rotates centering. If the swinging portion rotates in the direction of the arrow, for example, a force in the compression direction is applied to the first load cell 6 and a force in the tension direction is applied to the second load cell 12.

Therefore, even if thermal displacement occurs on the side of the first torque detecting mechanism including the load cell 6, similar thermal displacement occurs on the side of the second torque detecting mechanism including the load cell 12, and the swinging portions respectively. It works in the opposite direction with respect to 1, and as a result, the balance of the oscillating portion 1 is not lost.

On the other hand, even if thermal displacement occurs in the first and second torque detecting mechanisms, they repel each other, and this force appears as the output of each load cell 6, 12. This relationship is expressed as follows.

Force applied to the first load cell: torque + force due to thermal displacement Force applied to the second load cell: torque + force due to thermal displacement By the way, when a compressive force is applied to the first torque detecting mechanism side, a tensile force is applied to the second torque detecting mechanism side, and conversely, when a tensile force is applied to the first torque detecting mechanism side, the second torque detecting mechanism side is compressed. Since the force is applied, when the force due to the thermal displacement is zero, the compression force applied to the first torque detection mechanism side = -the tensile force applied to the second torque detection mechanism side-the tension force applied to the first torque detection mechanism side-the- 2 The compression force applied to the torque detection mechanism side is established. Here, it is assumed that a compressive force is applied to the first torque detection mechanism side. At this time, each load cell output is expressed by (force applied to the first load cell-force applied to the second load cell) / 2 = (compressive force + force due to thermal displacement-tensile force + force due to thermal displacement) / 2 = (compressive force -Tensile force) / 2 = Compressive force applied to the first torque detection mechanism side = Tensile force applied to the second torque detection mechanism side, torque can be detected without being affected by the force due to thermal displacement.

[0013]

As described above, according to the present invention, two sets of torque detection mechanisms are provided, and the outputs of the respective detection mechanisms are arranged so as to be opposite to each other. In addition, the two torque detection mechanisms are arranged at a position of about 90 ° with respect to the swing shaft, and one torque arm is arranged in the lower vertical position, so that a compact torque can be obtained as a whole. It has advantages such as the provision of a meter.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional torque detection device.

[Explanation of symbols]

1 ... Oscillating part 2 ... First torque arm 3 ... swing axis 4 ... Hydraulic levitation unit 5: Fixed base 6 ... First load cell 11 ... Second torque arm 12 ... Second load cell

Claims (2)

[Claims] 1. A dynamometer oscillating shaft comprising a load cell attached to a torque arm fixed to an oscillating portion of a dynamometer, and a torque of a device under test being detected through the load cell. Two torque arms are arranged at a position substantially perpendicular to each other, and a load cell is arranged in each torque arm at a position where they act in directions opposite to each other with respect to the rotation of the swinging portion. Torque detection device. 2. The torque arm according to claim 1, wherein one of the two torque arms protrudes in a horizontal direction of the swinging portion, and the other one of the two torque arms projects in a vertical direction below the swinging portion. Torque detection device.