JP2011047906A - Load testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load testing device having a simple constitution capable of verifying the degree of keeping a rotational frequency in the fixed state, against fluctuation of a load torque. <P>SOLUTION: A load testing machine includes a load operation part for operating a load torque on a driving device to be tested which is a test object driven rotatively at a rotational frequency determined beforehand, and a load detection part for detecting an actual load working on the driving device to be tested. The load operation part includes a gage head connected and fixed to a driving shaft of the driving device to be tested, a gripping mechanism for gripping the gage head, and a gripping force variation means capable of adjusting a gripping force of the gripping mechanism. The load operation part loads a sliding friction torque between contact surfaces of a gripping part of the gripping mechanism and the gage head as a load torque. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is used to verify the characteristics of various types of rotary drive devices that are driven by using fluid pressure such as an electric motor or an air turbine, and in particular, how much the rotational speed changes when a variable load is applied to the rotary drive device. The present invention relates to a load test apparatus.

A conventional characteristic tester such as a motor applies a load to a rotating motor, measures the torque at the time when the magnitude of the load and the torque of the motor are balanced, and shows the relationship between the rotation speed and the torque as a motor rotation speed-torque curve. It is used as. In actual selection, a motor having characteristics such that the load under the usage conditions is equal to or less than the torque curve is selected, and the rotational speed of the motor is controlled.
However, it is not clear from this characteristic curve whether or not the rotational speed is kept constant when the load torque fluctuates, and it is not known unless it is actually used. For example, in the case of a machine tool, such a fluctuation in the rotational speed is an important characteristic because it affects the processing accuracy of the cutting surface and the grinding surface.

Therefore, it is conceivable to use a conventional characteristic tester to detect a change in the rotational speed of the motor by changing the load. However, a commercially available product is generally a tester up to about 20,000 rpm, for example, 100,000 rpm. There are few things that can be tested up to high speed rotation.
In particular, in recent years, high-speed motors using air pressure have been used as motors for spindles of machine tools, and it is required to verify the characteristics in such high-speed rotation regions.

As a conventional characteristic tester, for example, as described in Patent Document 1, a device using a powder clutch is known. However, a device using such a powder clutch is complicated in structure and cost. There is a risk that the powder is deteriorated in the high speed rotation range.
In addition, it is generally known to add a load motor, but in this case as well, the apparatus is complicated and expensive, and the control system becomes complicated.

JP-A-7-151618

  The present invention has been made in response to the above-described demand, and provides a load test apparatus having a simple configuration capable of verifying how constant the rotation speed can be maintained with respect to load fluctuations. There is to do.

In order to achieve the above object, the present invention includes a load application unit that applies a load torque to a drive device under test that is a test target that is rotationally driven at a predetermined rotational speed.
A load detection device comprising a load detection unit that detects an actual load acting on the drive device under test,
The load acting unit includes a measuring element coupled to a drive shaft of a drive device to be tested, a holding mechanism for holding the measuring element, and a gripping force variable means for adjusting the holding force of the holding mechanism. And a sliding friction torque between the contact surfaces of the gripping portion of the gripping mechanism and the measuring element is loaded as a load torque.

Further, in addition to the above configuration, a rotation speed detector for detecting the rotation speed is provided, and the fluctuation of the rotation speed can be measured according to the load fluctuation detected by the load detection means.
Moreover, it is preferable to have a cooling means for cooling the gripping portion of the probe by the gripping mechanism.
More specifically, it has a base and a turntable provided so as to be rotatable with respect to the base, the load acting part is mounted on the turntable, and the drive device under test is driven by the rotating shaft of the turntable. The shaft is fixed with respect to the base so that it is coaxial, and a contact portion is provided between the turntable and the base so as to contact each other in the rotation direction of the turntable. A load sensor is provided.

According to the present invention, the load acting part is constituted by a gripping mechanism that sandwiches the measuring element between the gripping parts, and a very simple mechanism in which the friction torque is applied between the contact surfaces of the gripping part and the measuring element, The load can be changed by simply adjusting the gripping force.
In addition, it is possible to cope with various driving devices only by changing the size and shape of the detector.

If the rotation speed can be detected by the control system on the drive device side, the information from the detector on the drive device side can be used. However, if the rotation speed measuring means is provided, the rotation speed cannot be detected on the control system side. Even if there is a rotation speed detection unit on the control system side, the rotation speed can be verified, and a system for detecting the rotation speed can be arbitrarily set.
Furthermore, if a cooling means is provided, the temperature rise of the sliding contact portion can be reduced, and further high-speed rotation can be achieved.
In addition, the load acting part is mounted on the turntable, and the drive device under test is fixed to the base so that the rotation shaft and the drive shaft of the turntable are located on the same axis, and the load is placed between the turntable and the base. By arranging the detector, torque can be detected more easily.

FIG. 1 shows a principle configuration of a load test apparatus according to the present invention. FIG. 1 (A) is a plan configuration diagram, and FIG. 1 (B) is a schematic diagram showing a longitudinal section. (A) is the schematic of an apparatus structure in case a measuring element is disk shape, (B) is a graph which shows an example of a measurement result. FIG. 3A is a diagram showing a more specific configuration of the load test apparatus of the present invention, and FIG. 3B is a diagram showing a rotation speed detector.

The present invention will be described in detail below based on the embodiments shown in the drawings.
FIG. 1 shows a schematic configuration of a load test apparatus according to an embodiment of the present invention.
In other words, the load test apparatus 1 is actually applied to a load application unit 10 that applies a load torque to a drive device under test 100 that is a test object that is rotationally driven at a predetermined number of revolutions, and to the drive device under test 100. The load detection unit 20 for detecting the load and the rotation speed detector 30 for detecting the rotation speed are provided, and these components are rotatable with respect to the base 200 and the base 200 via the bearing 210. Is attached to the turntable 220.

In this embodiment, the load application unit 10 is attached to the turntable 220, and the drive device under test 100 is attached to the base 200 side via a support member.
The load application unit 10 includes a measuring element 11 that is connected and fixed to a drive shaft of the drive device under test via a coupling 14, a holding mechanism 12 that holds the measuring element 11, and a holding force of the holding mechanism 12 that is variable. A gripping force adjusting unit 13 serving as a gripping force varying unit, and the sliding friction torque between the gripping surface of the gripping mechanism 12 and the measuring element 11 is loaded as a load torque T.
The drive device under test 100 can be applied to a high-speed rotation drive device such as an air turbine. However, an electric motor may be used, and load tests on various rotation drive devices are possible.

The gripping mechanism 12 includes, for example, a pair of gripping pieces 121 and 121 and an actuator 122 that contacts and separates the gripping pieces 121 and 121. The grip pieces 121, 121 may be configured to move in parallel or may be configured to open and close. The grip pieces 121 do not have to be a pair and may be three or more. The actuator 122 may be driven by a fluid pressure cylinder such as air pressure or hydraulic pressure, or may use an electric motor.
The gripping force adjusting unit 13 is configured by a pressure control valve or the like that controls the fluid pressure when a fluid pressure cylinder is used, and a current value or the like is controlled in the case of an electric motor.

  The test probe 11 is constituted by a pin gauge having a circular cross section in the illustrated example. Note that the test gauge may be a disk gauge having a circular disk portion 11a as shown in FIG. In this case, the load may be applied by sandwiching the front and back surfaces of the disk portion 11a by the gripping pieces 121, 121 in the direction parallel to the rotation axis. Further, as indicated by a two-dot chain line, the outer periphery of the disk portion 11a may be gripped.

The load detection unit 20 is provided with a contact portion that contacts each other in the rotational direction of the turntable 220 between the turntable 220 and the base 200, and a load sensor 21 as a load detection portion is provided at the contact portion. is there. That is, between the base 200 and the turntable 220, a load sensor 21 and a pressing portion 22 that comes into contact with the load sensor 21 are provided so as to contact each other in the rotation direction of the turntable 220. In the illustrated example, the load sensor 21 is fixed to the base 200 side, and the pressing portion 22 is provided on the turntable 220 side. Of course, the load sensor 21 may be provided on the turntable 220 and the pressing portion 22 may be provided on the base 200 side. In this example, the load sensor is constituted by a piezoelectric element, converts the load into a voltage change, and can detect the torque from the rotation radius R from the center O of the turntable 220 to the load sensor 21.
The load detection unit 20 may not only detect the load by such a load sensor, but also detect the distortion in the twist direction of the probe 11 and calculate the torque from the torsional deformation. Various methods for converting the force involved into an electric signal and converting the displacement due to torque into an electric signal can be applied.
The rotation speed detector 30 is an encoder that is provided on the base 200 side and converts the mechanical rotation of the probe 11 into an electrical signal such as a pulse signal.

Detection information from the load sensor 21 and the rotation speed detector 30 is input to the computer 16. The computer 16 calculates the load torque from the rotation radius R stored in advance from the information from the load sensor 21 and accumulates the data. Although not particularly shown, the computer 16 has a central processing unit (CPU) and a memory for storing data and various programs. The pulse information from the rotation speed detector 30 is read simultaneously with the torque information, and the load The rotational speed data is stored in association with the torque, and the stored load torque and rotational speed can be displayed on the monitor 17 or output to a printer or the like as necessary.
Further, the gripping force adjusting unit 13 may be controlled by the computer 16. For example, in the case of a fluid pressure actuator, the pressure adjustment valve may be controlled according to the command value. However, the adjustment of the fluid pressure actuator may be performed manually. Further, the rotational speed control of the drive device under test 100 may be performed by the computer 16.

Moreover, in order to cool the contact part which generate | occur | produced by the frictional sliding during measurement, you may provide the cooling tank 18 as a cooling means. For example, water may be used as the cooling medium of the cooling tank 18, the cooling tank 18 may be disposed on the turntable 220, and the contact portion between the gripping mechanism 12 and the measuring element 11 may be submerged in the cooling medium.
As other cooling means, a cooling medium such as running water may be passed through the contact portion between the gripping mechanism 12 and the measuring element 11, cooling air may be blown by a cooling fan, or a Peltier element or the like. You may make it cool.

FIG. 3 shows a device configuration in which the device of FIG. 1 is further embodied.
The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.
In the illustrated example, an air turbine spindle that is rotationally driven by air pressure is illustrated as the drive under test 100.
A parallel clamp is used for the gripping mechanism 12 constituting the load acting unit 10. In order to immerse the grip piece 121 from above in the cooling tank 18, the grip piece 121 is vertically long from the main body of the gripping mechanism 12 toward the cooling tank 18, and the probe 11 is sandwiched between the tip portions. It has become.
In addition, a rotation speed detector 30 is provided, and is provided on a mounting plate 43 to which a shaft 41 standing on the base 200 is fixed. The mounting plate 43 extends horizontally from the shaft 41 toward the measuring element 11, is attached to a stay 42 that is fixed at one end to the shaft 41, and has a pair of arms so that the tip on the measuring element 11 side sandwiches the measuring element 11. As shown in FIG. 3B, a light emitting unit 31 such as an LED is provided on one of the arms, and a light receiving unit 32 such as a photosensor is provided on the other, and a light emitting unit is provided on each arm. A hole 30 a for allowing light to pass from 31 toward the light receiving unit 32 is provided. The shaft 11 is provided with a notch 11b so that light extending from the light emitting portion 31 toward the light receiving portion 32 is transmitted when it matches the notch 11b, and is shielded at portions other than the notch 11b. The light receiving pulse is generated once every 11 revolutions. The configuration of the rotational speed detector 30 is not limited to this, and various configurations can of course be adopted. In short, the rotational displacement of the shaft 11 or the drive device to which the shaft 11 is coupled is included. Various means for detecting the mechanical rotational displacement of the drive shaft by converting it into an electrical signal can be adopted.

In the load test apparatus having the above configuration, a load is applied as follows, and torque fluctuation is measured.
First, the device under test 100 is attached from the base 200 to the head unit 202 disposed above the turntable 220 via the support column 201. A probe 11 made of a pin gauge corresponding to the drive device under test 100 is connected and supported by a probe support part.
Then, the rotation of the drive device under test 100 is controlled at a predetermined number of rotations (the number of rotations to be tested) arbitrarily set in advance. The measuring element 11 connected to the drive device under test 100 is also rotated at a predetermined number of revolutions. The measuring element 11 is driven by the actuator 122 of the gripping mechanism 12 and sandwiched at a predetermined value by the gripping pieces 121 and 121. Then, a braking torque T is applied as a load to the drive device 100 under test via the measuring element 11. The reaction force of the braking torque T acts on the rotating table 220 as the detected torque Tc through the load application unit 10 provided with the gripping mechanism 12, and the rotating table 200 tries to rotate in the clockwise direction in the figure, and the sensor contact portion 22 Pressed against the load sensor 21. The magnitude of the pressing load is converted into voltage information and sent to the computer 16, and the detected torque Tc is calculated from the rotational radius R stored in advance by the computer 16, and the calculated value is displayed on the monitor 17, for example. .

On the other hand, information from a rotational speed detector 30 as rotational speed detection means is input to the computer 16, and the rotational speed is calculated by the computer 16.
Then, by changing the gripping force of the gripping mechanism 12 continuously or stepwise by the gripping force adjusting unit 13, a change in the number of rotations when it fluctuates is monitored.
FIG. 2B is an example of a test result of a change in the rotational speed. In this example, the load is continuously increased, and when the detected torque T reaches the limit torque Tmax, the rotation speed N decreases, and the constant rotation speed is maintained until the limit torque Tmax. Is shown.
In this way, the load acting unit 10 is configured by the gripping mechanism 12 that sandwiches the measuring element 11, and the gripping force is changed by a very simple mechanism in which only the friction torque between the contact surfaces with the gripping mechanism 12 is applied. Thus, a variable load can be easily applied. In addition, it is possible to cope with various driving devices only by changing the size and shape of the probe 11.

If the rotation speed N can be detected by the control system on the drive under test 100 side, the rotation speed information on the drive under test 100 side can be used, but a rotation speed detector 30 is provided as a rotation speed measuring means. In this case, even when the rotational speed cannot be detected on the control system side, it can be detected, and the precision of rotational speed detection can be arbitrarily set.
In addition, this invention is not limited to the said Example, A various change can be added within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Load test apparatus 10 Load action part 11 Measuring element 11a Disk part 12 Grip mechanism 121 Grip piece 122 Actuator 13 Grip force adjustment part 14 Coupling 16 Computer 17 Monitor 18 Cooling tank 20 Load detection part 21 Load sensor 22 Press part 30 Rotation speed Detector 31 Light emitting section, 32 Light receiving section 100 Drive apparatus under test 101 Drive shaft 200 Base 210 Bearing 220 Turntable O Center R Turning radius T Braking torque (load)
Tc Detection torque Tmax Limit torque

Claims (4)

A load application unit that applies a load to the drive device under test to be tested and rotated at a predetermined number of revolutions;
A load test device comprising a load detection unit for detecting an actual torque acting on the drive device under test,
The load acting unit includes a measuring element coupled to a drive shaft of a drive device to be tested, a holding mechanism for holding the measuring element, and a gripping force variable means for adjusting the holding force of the holding mechanism. And a load test apparatus that loads the sliding friction torque between the contact surfaces of the gripping mechanism and the measuring element of the gripping mechanism as a load.   2. The load test apparatus according to claim 1, further comprising a rotation speed detector for detecting the rotation speed, wherein the fluctuation of the rotation speed can be measured according to the load fluctuation detected by the load detection means.   The load testing apparatus according to claim 1, further comprising a cooling unit that cools a gripping portion of the probe by the gripping mechanism.   A base and a turntable provided to be rotatable with respect to the base, the load acting part is mounted on the turntable, and the drive device under test is positioned so that the rotation shaft and the drive shaft of the turntable are coaxial. A contact portion that is fixed with respect to the base and is in contact with each other in the rotation direction of the turntable between the turntable and a load sensor as a load detection portion is provided at the corresponding contact. The load test apparatus according to any one of claims 1 to 3, wherein the load test apparatus is characterized by the following.

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