JPS6027938B2 - Rotor acting force measuring device - Google Patents

Description

[Detailed description of the invention] This invention relates to rotating machines (including linear electric machines).

By detecting the horizontal and vertical components of the magnetic stress that occurs two-dimensionally on the stator of the rotor (the same applies hereinafter), it is possible to simultaneously measure the acting force acting in the radial and circumferential directions of the rotor. This relates to a measuring device. In addition,
In this specification, the term "rotor" includes a moving body in a linear electric machine.

In a secondary magnetic stress measuring device, both the circumferential and radial components of the force acting on the rotor are measured using separate measuring devices, for example, the force acting in the circumferential direction of the rotor is measured at the rotor shaft end. An attached torque meter detects the force acting in the radial direction of the rotor, and a load cell installed in contact with the stator detects the force acting in the radial direction of the rotor. For this reason, conventional measuring devices require a support structure to prevent forces from acting on the load cell in a direction other than the force to be detected, which may result in the measuring device becoming large-scale.

Further, in the above-mentioned support structure, it is inevitable that the stator will be displaced during measurement due to the load cell detection mechanism. Normally, the stator vibrates due to electromagnetic force, and the frequency is 200H.
Since it also reaches Z, there is a possibility that the inertial force becomes non-negligible compared to the detected electromagnetic stress. Since the stator is in contact with the support structure, it is also necessary to consider the influence of frictional force at the contact portion. As described above, conventional magnetic stress measuring devices have had drawbacks such as difficulty in measuring with sufficient accuracy despite the large scale of the device. This invention was made for the purpose of eliminating the drawbacks of the above-mentioned follower device.
A load cell is interposed between the rotator and the support base that supports it, and the stator is mounted.

The structure is supported by a load cell, and the shape of the load cell,
By selecting the strain gauge attachment position and strain gauge connection method, the strain generated on the load cell due to electromagnetic stress can be separated into components in the rotor circumferential direction and radial direction and detected with high accuracy. be. below,
DESCRIPTION OF THE PREFERRED EMBODIMENTS A linear motor testing device as an embodiment of the rotor acting force measuring device of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing the configuration of a linear motor testing device in an embodiment of the rotor acting force measuring device of the present invention, and FIG. 2 is a shape of a load cell used in the linear motor testing device shown in FIG. 1. FIG.

In FIGS. 1 and 2, 1 is a rotor, 2 is a stator, 3 is made of a metal material with a small spring constant, such as chromium molybdenum, and is arranged symmetrically with respect to a horizontal plane passing through the center of the rotor 1. and has first to eighth side members, and has an outer diameter of 8.
The load cell is formed into a rectangular cylindrical shape, and the seventh side member is fixed to the stator 2, and the third side member is fixed to the support base 12.

4 to 11 are strain gauges, strain gauges 4 and 5 are on the first side member, strain gauge 10 is on the fourth side member,
Strain gauges 6 and 7 are attached to the fifth side member, and strain gauge 1 is attached to the fifth side member.
1 is attached to the sixth side member, and strain gauge 8 is attached to the eighth side member.

These strain gauges 4 to 7 are attached at positions 00 and 450 with respect to the center line D-E, respectively, as corresponding positions on the load cell 3 that can detect stress in the vertical direction and strain gauges 8 to 11 in the horizontal direction. has been done. 12 is a support base that supports the stator 2 via the load cell 3, and 13 is a set screw for preventing resonance, which is attached to a part of the support base 12 and can fix the stator 2 when the linear motor is started or stopped. It looks like this.

14 is a bolt that fixes the stator 2 and the load cell 3, 15
is a bolt that fixes the load cell 3 and the support base 12.

Next, the operation of the near motor testing apparatus constructed as above will be explained based on the drawings. Since the load cell 3 is fixed to the stator 2, the electromagnetic stress generated in the stator as the rotor rotates is concentrated on the joint surface of the load cell 3 with the stator 2.

By detecting the horizontal component (component force) and the vertical component (component force) of the electromagnetic stress concentrated on the joint surface, the acting forces acting in the radial direction and circumferential direction of the rotor 1 can be detected simultaneously. Here, if the above horizontal component force F acts in the direction of the center line DE, and the vertical component G acts in a direction perpendicular to the center line DE and in a direction that includes the plane of the paper, then the stress acting on the surface of the load cell to which the strain gauge is attached is , C, C', d, d' can be expressed as proportionality constants indicating the amount of strain with respect to stress as follows.

In other words, the mounting surface of the strain gauge 4 has C'F+d'G.
, C'F-d'G on the mounting surface of strain gauge 5, C'F+d'G on the mounting surface of strain gauge 6, strain gauge 7
C'F- is G on the mounting surface of strain gauge 8, CF1 dG is on the mounting surface of strain gauge 8, and CF10 dG is on the mounting surface of strain gauge 9.
, a stress of CF-dG acts on the mounting surface of the strain gauge 10, and a stress of CF+dG acts on the mounting surface of the strain gauge 11. This means that the strain gauges 8 and 9 can be
, 10, 11 are expanded, and the strain gauges 9, 11 are expanded due to the vertical component force, and the strain gauges 8, 10 are contracted. Here, the load cell is on the center line D-E
Since the strain gauges are symmetrical and octagonal, each value of expansion or contraction occurring in each strain gauge is considered to be equal, and the sum of the output signals of strain gauges 8 to 11 represents the signal corresponding to the horizontal component force F'. It turns out. In order to obtain such horizontal component force F, a well-known bridge circuit method may be used.

For example, in FIG. 3, the strain gauges 8 to 11 connected in series are referred to as a resistor G, and together with the detection resistors (T2 to G4) constitute a bridge circuit.

ej is a power supply voltage, and ΔC is a bridge voltage, which is a signal indicating the horizontal component force. Note that such a bridge circuit is an example of the first means. Furthermore, the strain gauges 4 to 7 are expanded by the horizontal component force F, and the strain gauges 4 and 6 are expanded by the vertical component G, and the strain gauges 5 and 7 are contracted. Therefore, the difference between the sum of the output signals of the strain gauges 4 and 6 and the sum of the output signals of the strain gauges 5 and 7 represents a signal corresponding to the vertical component G. This vertical force component G can be determined similarly to the horizontal force component F using a well-known bridge circuit. In Fig. 3, resistance G, ~G4 is connected to strain gauge 4~
7, the strain gauges 4 to 7 may be connected in a bridge manner.

ΔC is a signal indicating the vertical component force as a bridge voltage. This bridge circuit is an example of the second means. As described above, in this invention, strain gauges can detect stress in the horizontal and vertical directions between the stator that urges the rotor of a rotating machine and the support base that supports this stator. Equipped with an octagonal cylindrical load cell installed at the
By selecting the strain gauge connection method, it is possible to simultaneously detect the electromagnetic stress components in the radial and circumferential directions of the rotor independently and simultaneously with high precision.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of a linear motor testing device in an embodiment of the rotor acting force measuring device of the present invention, and FIG. 2 is a shape of a load cell used in the linear motor testing device shown in FIG. 1. FIG. 3 is a Fujitsugi diagram showing the bridge circuit. In the figure, 1 is a rotor, 2 is a stator, 3 is a load cell, 4 to 11 are strain gauges, 12 is a support base, 13 is a resonance prevention set screw, 14 and 15 are bolts, G and ~G4 are resistors, ej is a power supply voltage, and 4e is a bridge voltage. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 The first rotor is arranged symmetrically with respect to a horizontal plane passing through the rotation center of the rotor, and is fixed between the stator and the support base, and
or a cylindrical load cell forming an octagon from an eighth side member, the third or seventh side member is fixed to the rotor, and the first and fifth side members are parallel to the horizontal plane. and the third and seventh side members are arranged perpendicularly to the horizontal plane, and the second, fourth, sixth, and eighth side members are arranged inclined to the horizontal plane, and the first or seventh side members are arranged perpendicularly to the horizontal plane. a first strain gauge attached to a first surface of the fifth side member that faces the horizontal surface; and a second strain gauge that faces the first surface of the fifth side member;
a second strain gauge attached to the surface of the second strain gauge;
and 8th, 4th and 6th, 2nd and 4th, 6th and 8th
third and fourth strain gauges attached to the outer surfaces of at least one pair of side members not facing the horizontal surface out of the four pairs consisting of the output of the first strain gauge and the second strain gauge;
and a second means for detecting the sum of the output of the third strain gauge and the output of the fourth strain gauge. Rotor acting force measuring device.