JP3670816B2 - Screw compressor test method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a performance test in a screw compressor that has a male rotor and a female rotor in a casing, and that both rotors rotate while maintaining a minute gap by a timing gear fixed to each rotor by an interference fit.
[0002]
[Prior art]
Assembling of a conventional screw compressor, in particular, position adjustment between rotors is fixed to a female rotor, for example, without a timing gear fixed to the male rotor, as described in Japanese Patent Application Laid-Open No. 1-155089. Rotate the male rotor in both forward and reverse directions while braking the female rotor via the timing gear, and measure the gap between the two rotors using the rotational phase difference of each male and female rotor measured by an encoder during the rotation. (Rotor backlash measurement). Next, with respect to the measured gap between the two rotors, the gap between the forward side and the backward side is distributed at a desired ratio to set a minute gap between the two rotors (distribution adjustment).
[0003]
That is, the timing gear is fixed to the male rotor with an interference fit and the timing gear of the female rotor is constrained, and pressure oil is applied between the male rotor and the timing gear fixed to the male rotor to tighten between the two. By loosening the fit and hitting the tooth surface of the male rotor with a hammer, a relative displacement occurs between the male rotor and the timing gear fixed to the male rotor, and both shims (thickness gauges) are attached. Insert between the rotors to check whether the minute gap between the two rotors is the desired value (shim measurement), repeat hammering and shim measurement to obtain the desired minute gap between the rotors (value) Set to.
[0004]
After that, the screw compressor is tested. In this test, the screw compressor main body was installed in the test apparatus specified in JIS B 8341, and it was operated (rotated) under the required conditions to confirm that the temperature of each part reached almost constant, and the discharge pressure, discharge temperature, Intake air volume (exhaust air volume), vibration noise, total heat insulation efficiency, etc. (hereinafter referred to as screw compressor performance) can be measured by air pressure measurement, flow rate measurement, temperature measurement, etc. using the orifice plate in the piping of the test equipment. It is determined whether the performance of the screw compressor satisfies the specification value, and the performance (quality) is guaranteed by the actually measured value.
[0005]
[Problems to be solved by the invention]
In the above-mentioned prior art, since the minute gap between the rotors is manually set (distribution adjustment), not only does it take time to measure shims, but hammering is affected by the skill level of the operator and the accuracy of the distribution adjustment The distribution was unreliable and the reliability of the distribution adjustment was low. The temperature increase in the performance test of the screw compressor is accompanied by the thermal expansion of the rotor, and the increase in driving force causes the rotor to be twisted or deformed. There is a risk of damaging the coating film and destroying the bearing supporting the rotor.
[0006]
Therefore, in the performance test of the screw compressor, the rotor is rotated at a low speed so that the ramp of pressure increase / temperature rise is gentle so that the test can be stopped as soon as abnormal noise occurs due to contact between the rotors. There was a problem that the time required for the performance test could not be shortened and the performance test took time.
[0007]
SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a test method for a screw compressor which can efficiently measure the performance of the screw compressor with a short time until each part reaches a substantially constant temperature.
[0008]
[Means for Solving the Problems]
The screw test method according to the present invention that achieves the above object is achieved by rotating the male rotor and the female rotor while holding a minute gap by a timing gear fixed to each rotor in the casing, so that the temperature of each part reaches substantially constant. In the screw compressor test method that measures the performance of the screw compressor in the state, the suction air volume or discharge temperature is measured with respect to the rotor backlash of the normal screw compressor, and the correlation characteristics are set as statistical processing In the correlation characteristic, the lower limit value (Qdl) of the suction air volume or the upper limit value (Tup) of the discharge temperature is set, and the allocation ratio is set for the screw compressor to be tested, and the screw compression to be tested is set. the machine, the suction air volume lower limit (QDL) or the upper limit of the discharge temperature (Tup) is set of , And either suction write airflow about the correlation characteristic distribution ratio is set is above a lower limit value (QDL), or when the discharge temperature is determined to be below the upper limit value (Tup), by performing up or heating That is, the performance of the screw compressor is measured by rapidly increasing the pressure or raising the temperature.
[0009]
The screw compressor to be tested changes the distribution ratio when the intake air volume is lower than the lower limit value Qdl or the discharge temperature is higher than the upper limit value Tup depending on the set distribution ratio.
[0010]
The correlation characteristic is that one timing gear is constrained while the other timing gear is loosely fixed by an interference fit, and a torque is intermittently applied to the rotor provided with the other timing gear via a servo motor. This is measured by applying and adjusting the fine gap between the two rotors to a desired one.
[0011]
According to the present invention, it is possible to provide a test method for a screw compressor that can efficiently measure the performance of the screw compressor with a short time until each part reaches a substantially constant temperature.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the test method of the present invention will be described according to one embodiment shown in FIGS. First, FIG. 1 shows a screw compressor and its rotor backlash measuring device. In FIG. 1, a male rotor 2 and a female rotor 3 are supported in a radial and thrust direction by a housing 1 by bearings, and the housing 1 is fixed to a frame 21 for rotor backlash measurement.
[0013]
The male rotor 2 is rotationally driven by a direct drive motor (hereinafter referred to as a DD motor) 22 which is a servo motor, and the rotation angle θ 1 is detected by an encoder 23. The rotation angle θ2 of the female rotor 3 is detected by the encoder 24.
[0014]
The male timing gear 4 is engaged with the inclined external gear 25. The external gear 25 is rotationally driven by a direct drive motor (hereinafter referred to as a DD motor) 26. A support member 27 is provided on the assembly frame 21, and a direct motor (hereinafter referred to as a DD motor) 28 that is a servo motor is installed on the support member 27. The fixed portion of the linear guide 29 is installed on the support member 27, the movable part is coupled with the female screw 30 screwed to the rotation shaft of the DD motor 2 8. A DD motor 26 is provided on the movable part of the linear guide 29. Accordingly, the external gear 25 is guided by the linear guide 29 and moves up and down by the rotation of the DD motor 28. The rotation angle θ3 of the DD motor 28 is detected by the encoder 31.
[0015]
A female timing gear 5 is fixed to the female rotor 3 by an interference fit, and a torque can be applied by a direct drive motor (hereinafter referred to as a DD motor) 10 that is a servo motor fixed to the frame 21 via the brake gear 9. It has become.
[0016]
The hydraulic cylinder 6, the piston 7 and the hydraulic equipment 15 are for attaching / detaching the male timing gear 4 to / from the male rotor 2. The attaching / detaching process will be described later.
[0017]
Reference numeral 32 denotes a control personal computer. When a drive signal is output to the drivers 34 to 37 via the bus system 33, the motors 10, 22, 26 and 28 are operated. The rotation angles θ1 to θ3 detected by the encoders 23, 24, and 31 are sent to the personal computer 32 via the interpolator 38 and the bus system 33, and are used for feedback of control, creation of a correlation characteristic diagram, and the like.
[0018]
As described in Japanese Patent Laid-Open No. 1-155089, the gap between the rotors 2 and 3 is measured by engaging the rotors 2 and 3 in the housing 1 without the male timing gear 4 and then engaging the female rotor 3 with the female timing gear. 5. Rotate the male rotor 2 in both forward and reverse directions while applying torque with the brake gear 9 and the DD motor 10, and measure the rotational phase difference between the rotors 2 and 3 measured during the rotation (rotor backlash). measurement). The rotation angle θ1 of the male rotor 2 is measured by the encoder 23, the rotation angle θ2 of the female rotor 3 is measured by the encoder 24, the male rotor 2 is rotated in the forward and reverse directions, and the rotation angles θ1 and θ2 are captured by constant sampling. The rotation angle difference (θ1−θ2) is calculated and obtained. Torque is applied by the DD motor 10 via the brake gear 9 in order to reliably bring the rotors 2 and 3 into contact with each other during measurement.
[0019]
After the rotor backlash measurement, the male timing gear 4 is press-fitted into the male rotor 2. As shown in FIG. 2, the hydraulic cylinder 6 and the piston 7 are combined with the male timing gear 4 to apply hydraulic pressure to the hydraulic chamber 8 with the hydraulic equipment 15 to enlarge the inner diameter of the male timing gear 4 and simultaneously insert (press-fit) direction. Apply thrust to Then, the male timing gear 4 meshes with the helical teeth of the female timing gear 5. At this time, the male timing gear 4 is rotated by the external gear 25 as indicated by the arrow D. Then, the male timing gear 4 rotates and proceeds in a shape twisted in the oblique direction of the helical teeth of the female timing gear 5. The DD motor 28 moves the external gear 25 in accordance with the moving speed of the male timing gear 4 so that the rotational force can be sufficiently transmitted from the external gear 25 to the male timing gear 4.
[0020]
As a result, the male timing gear 4 is pushed by the external gear 25 and pressed into the male rotor 2 while the gap between the timing gears 4 and 5 is maintained.
[0021]
FIG. 3 shows a state of a minute gap between the rotor and the timing gear in the screw compressor shown in FIG. 1 as a model, where the male timing gear 4 and the female timing gear 5 are engaged (indicated by a one-dot chain line a). portion) is shown in dashed line circle upper enlarged, it is shown in dashed line circle Otsu an enlarged point the male rotor 2 and female rotor 3 is engaged (indicated by one-dot chain line circle b). There is no gap B1 between the timing gears 4 and 5 on the forward side, and there is a gap B2 on the reverse side. Further, minute gaps G1 and G2 are set on the forward side and the reverse side of the rotors 2 and 3, respectively.
[0022]
The minute gaps G 1 and G 2 change by shifting the fixed position of the male timing gear 4 with respect to the male rotor 2.
[0023]
As to which position should be fixed, for example, as described in Japanese Patent Laid-Open No. 1-155089, the male timing gear 4 is removed from the male rotor 2, and the female rotor 3 is braked via the female timing gear 5. While rotating, the male rotor 2 is rotated in both forward and reverse directions, and the rotational phase difference between the rotors 2 and 3 is measured by the encoders 23 and 24 connected to the rotors 2 and 3 during the rotation (this operation is called measurement work). Call).
[0024]
Then, by using this measurement result, the small timing gaps G1 and G2 are obtained on the forward side and the reverse side of the rotors 2 and 3 so that a desired compression performance can be obtained, and the male timing gear is set to the target position. 4 is fixed to the male rotor 2 by an interference fit (distribution adjustment).
[0025]
When performing this distribution adjustment, the male timing gear 4 is restrained by the interference fitting with the male rotor 2 while restraining the female timing gear 5, and torque is intermittently applied to the male rotor 2 via the servo motor 22. Then, the minute gaps G1 and G2 between the rotors 2 and 3 are set to have a desired distribution ratio, or torque is intermittently applied to the male rotor 2 via the servo motor 22 to intermittently apply torque. each smaller torque than the torque that is intermittently applied torque or by static friction in the drive system by the servo motor 22 is applied to the forward and reverse during. An intermediate value of the relative positions of the rotors 2 and 3 at the time of applying the forward and reverse torque is obtained, and the next intermediate distance is obtained from the intermediate value and a desired minute gap deviation between the rotors 2 and 3. By applying an appropriate torque, the minute gaps G1 and G2 between the rotors 2 and 3 are made to have a desired distribution ratio. By performing such an operation, even if the rotors 2 and 3 and the timing gears 4 and 5 are temporarily elastically deformed at the time of torque application, the next torque application is performed and the distribution adjustment accuracy is very high. However, the rotors 2 and 3 are not in contact with each other.
[0026]
FIG. 4 shows a situation in which the minute gap between the rotor and the timing gear in the screw compressor is set to a desired distribution adjustment position.
[0027]
Here, a ratio α (= G2 / G0 × 100) of the gap of the reverse minute gap G2 to the sum G0 (= G1 + G2) of the minute gaps G1 and G2 of the forward side and the reverse side is referred to as a distribution ratio (gap ratio) . To do.
[0028]
A correlation characteristic diagram of the sum G0 of the minute gaps G1 and G2 on the forward side and the reverse side, the suction air amount, and the discharge temperature will be described with the distribution ratio α as a parameter.
[0029]
The suction air volume and the discharge temperature are measured using a test apparatus defined in JIS B 8341. Each measurement of the number of screw compressor showing normal characteristics, using a personal computer 32, the table calculation function statistical processing by graphed, to create a correlation characteristic diagram showing the correlation characteristic (FIG. 7 Step 1). Examples thereof are shown in FIGS.
[0030]
5 and 6, Qs is a reference value of the suction air amount, Qdl is a lower limit value of the suction air amount, Ts is a reference value of the discharge temperature, and Tup is an upper limit value of the discharge temperature.
[0031]
Next, a description will be given of performing a performance test by incorporating a screw compressor body into a test apparatus defined in JIS B 8341 for a certain arbitrary screw compressor (step 2 in FIG. 7).
[0032]
The sum G0 and the distribution ratio (gap ratio) α of the minute gaps G1 and G2 on the forward side and the reverse side in the screw compressor as the test object can be obtained from the measurement by the measuring device shown in FIG. Step 3).
[0033]
From FIG. 5 and FIG. 6, it is confirmed that the suction air volume in the screw compressor that is the test object is not less than the lower limit value Qdl and that the discharge temperature is not more than the upper limit value Tup (step 4 in FIG. 7). For example, considering a screw compressor in which the sum G0 of the small gaps G1 and G2 on the forward side and the reverse side is GN and the distribution ratio α is α = 20, according to FIG. 5, the suction air volume is about the reference air volume Qs. Further, according to FIG. 6, the discharge temperature is sufficiently lower than the upper limit value Tup, and it can be estimated that the performance of the screw compressor satisfies the specification value.
[0034]
Therefore, the assembly of the screw compressor is performed as scheduled, and the rotors may come into contact with each other to damage the coating film provided for protection on the surface of each rotor or destroy the bearing supporting the rotor ( It can be determined that there is no concern. If it can be predicted from FIGS. 5 and 6 that the intake air volume is near or below the lower limit value Qdl, or the discharge temperature is about the upper limit value Tup or higher, the screw compressor is assigned to the distribution ratio α by the measuring device of FIG. Is changed so that the suction air volume is not less than the lower limit value Qdl and the discharge temperature is not more than the upper limit value Tup.
[0035]
After that, the screw compressor main body is installed in the test apparatus specified in JIS B 8341 and the performance test is performed (step 5 in FIG. 7). Since it has been estimated that it is safe to shorten the time until each part reaches a substantially constant temperature, there is no problem.
[0036]
Thus, the performance of the screw compressor can be measured efficiently.
[0037]
Also, after performing maintenance on the operating screw compressor, when checking whether the screw compressor has returned to normal, the sum G0 and the distribution ratio of the small gaps G1, G2 on the forward side and the reverse side are also shown. After measuring α, it is determined in the above correlation characteristic diagram that the suction air volume is not less than the lower limit value Qdl and the discharge temperature is not more than the upper limit value Tup, and the performance test of the screw compressor is performed within a short time. Can be implemented. In particular, a large and large-capacity screw compressor is difficult to bring back to the production site when the installation site and the production site are far apart. However By using the correlation characteristics described above, and the assembly was disassembled and repaired at the installation site, it is possible to carry out the performance test on the spot, transportation is very efficient and not necessary.
[0038]
Further, for a screw compressor whose design, the sum G0 of the small gaps G1 and G2 on the forward side and the reverse side is known, the distribution ratio α is selected to be any value in order to satisfy the specification values of the intake air amount and the discharge temperature. or look Ri by correlation characteristics described above, with the position adjusted to the distribution ratio α in the measurement apparatus shown in FIG. 1, may be a measurement of performance tests.
[0039]
【The invention's effect】
As described above, according to the present invention, the time required for each part of the screw compressor to reach a substantially constant temperature is short, and the measurement for the performance test of the screw compressor can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a diagram showing a screw compressor and a rotor backlash measuring device according to an embodiment of the test method of the present invention.
FIG. 2 is a diagram illustrating a situation in which a male timing gear is fixed to a male rotor of the screw compressor shown in FIG.
FIG. 3 is a diagram for explaining a state of meshing between a rotor and a timing gear of the screw compressor shown in FIG. 1;
FIG. 4 is a diagram showing a state of meshing between a rotor and a timing gear of the screw compressor shown in FIG. 1 in relation to a rotation angle of a male rotor and a relative position of both male and female rotors.
FIG. 5 is a diagram showing a correlation characteristic between a gap between both rotors of the screw compressor and a ratio of a gap on the reverse side with respect to the gap between both rotors and a suction air amount.
FIG. 6 is a diagram showing a correlation characteristic between a gap between both rotors of the screw compressor and a ratio of a gap on the reverse side with respect to the gap between both rotors and a discharge temperature.
FIG. 7 is a diagram showing a process of performing a performance test of a screw compressor using the correlation characteristic diagrams shown in FIGS. 5 and 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing 2, 3 ... Rotor 4, 5 ... Timing gear 6 ... Hydraulic cylinder 7 ... Piston 8 ... Hydraulic chamber 9 ... Brake gear 10, 22, 26, 28 ... Motor 15 ... Hydraulic equipment 21 ... Frame 23, 24, 31 ... Encoder 25 ... External gear 27 ... Support member 29 ... Linear guide 30 ... Female screw 32 ... Control PC 33 ... Bus system 34 to 37 ... Driver 38 ... Interpolator

Claims (3)

A screw compressor that measures the performance of the screw compressor in a state where the male rotor and the female rotor are rotated while holding a minute gap by a timing gear fixed to each rotor in a casing, and the temperature of each part reaches almost constant. In the test method of
The suction air volume or discharge temperature is measured with respect to the distribution ratio for the rotor backlash of a normal screw compressor, and a correlation characteristic is set as a statistical process. In the correlation characteristic, the lower limit value (Qdl) of the suction air volume or the discharge temperature is set. An upper limit value (Tup) is set, and a distribution ratio is set for the screw compressor to be tested. The lower limit value (Qdl) of the suction air volume or the upper limit value (Tup) of the discharge temperature is set in the screw compressor to be tested. ) is set, and when either suction write airflow about the correlation characteristic distribution ratio is set is above a lower limit value (QDL), or discharge temperature is determined to be below the upper limit value (Tup), boost or buck A method for testing a screw compressor, wherein the performance of the screw compressor is measured by performing temperature.   In claim 1, when the screw compressor to be tested is determined to have a suction air volume of the lower limit value Qdl or lower, or a discharge temperature of the upper limit value Tup or higher, depending on the set allocation ratio, A screw compressor test method, characterized in that   2. The correlation characteristic according to claim 1, wherein the correlation characteristic is loosened by tightening the other timing gear with the rotor while restraining one timing gear, and the rotor provided with the other timing gear is connected via a servo motor. A test method for a screw compressor, characterized in that it is measured by applying torque intermittently and allocating and adjusting the minute gap between the rotors to a desired one.

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