羅茨風(fēng)機(jī)屬于容積式回轉(zhuǎn)風(fēng)機(jī)，真空變壓吸附制氧裝置（VPSA-O2）普遍使用羅茨鼓風(fēng)機(jī)和羅茨真空泵作為產(chǎn)氧過(guò)程氣體輸送的動(dòng)力設(shè)備。實(shí)際生產(chǎn)中，羅茨風(fēng)機(jī)在壓力頻繁突變的惡劣工況下運(yùn)行，因而頻繁發(fā)生振動(dòng)超標(biāo)的故障，引發(fā)制氧裝置全面停車(chē)，對(duì)生產(chǎn)穩(wěn)定造成嚴(yán)重影響。鑒于此，對(duì)制氧裝置羅茨風(fēng)機(jī)振動(dòng)故障發(fā)生的原因進(jìn)行查找分析，對(duì)維修技術(shù)改進(jìn)進(jìn)行摸索，從而有效減少振動(dòng)故障的發(fā)生，保障生產(chǎn)長(zhǎng)期穩(wěn)定進(jìn)行。

　　Roots blower belongs to the positive displacement rotary fan, and the vacuum pressure swing adsorption oxygen production unit (VPSA-O2) commonly uses Roots blower and Roots vacuum pump as power equipment for gas transportation in the oxygen production process. In actual production, Roots blowers operate under harsh conditions of frequent pressure fluctuations, resulting in frequent failures of vibration exceeding the standard, causing the oxygen production unit to shut down completely and seriously affecting production stability. In view of this, the causes of vibration faults in the Roots blower of the oxygen production unit were investigated and analyzed, and maintenance technology improvements were explored to effectively reduce the occurrence of vibration faults and ensure long-term stable production.

　　羅茨風(fēng)機(jī)因其對(duì)生產(chǎn)工藝適應(yīng)性強(qiáng)的優(yōu)點(diǎn)，成為真空變壓吸附制氧裝置中使用最廣泛的機(jī)械設(shè)備。產(chǎn)氧過(guò)程中，羅茨鼓風(fēng)機(jī)和羅茨真空泵分別起到正壓輸送原料空氣和真空解吸抽除廢氣的作用，需在空載壓力到滿載壓力的狀態(tài)下交替循環(huán)運(yùn)行，極不穩(wěn)定的負(fù)荷導(dǎo)致沖擊大，羅茨風(fēng)機(jī)頻繁發(fā)生振動(dòng)超標(biāo)引發(fā)聯(lián)鎖停機(jī)的故障，對(duì)制氧裝置作業(yè)率和下游工序生產(chǎn)組織影響嚴(yán)重。因此，只有查找羅茨風(fēng)機(jī)振動(dòng)故障根源，實(shí)施有效的措施加以改進(jìn)，從而減少故障的發(fā)生，方能保障制氧裝置的長(zhǎng)期穩(wěn)定運(yùn)行。

　　The Roots blower has become the most widely used mechanical equipment in vacuum pressure swing adsorption oxygen production units due to its strong adaptability to production processes. During the oxygen production process, the Roots blower and Roots vacuum pump play the roles of positive pressure conveying of raw air and vacuum desorption and extraction of exhaust gas, respectively. They need to operate alternately in a cycle from no-load pressure to full load pressure. The extremely unstable load leads to large impact, and the Roots blower frequently experiences vibration exceeding the standard, causing interlock shutdown faults, which seriously affect the operation rate of the oxygen production unit and the production organization of downstream processes. Therefore, only by identifying the root cause of vibration faults in Roots blowers, implementing effective measures to improve them, and reducing the occurrence of faults, can the long-term stable operation of oxygen production equipment be guaranteed.

　　真空變壓吸附制氧裝置（VPSA-O2）工藝原理

　　Process principle of vacuum pressure swing adsorption oxygen production unit (VPSA-O2)

　　VPSA制氧是利用變壓吸附法，以空氣為原料制取氧氣的一種新型常溫氣體分離技術(shù)。該法是基于分子篩對(duì)空氣中的氧、氮組分進(jìn)行選擇性吸附而使空氣分離獲得氧氣，通常稱為真空變壓吸附制氧法。當(dāng)空氣經(jīng)過(guò)壓縮、通過(guò)裝有分子篩的吸附塔時(shí)，氮?dú)夥肿觾?yōu)先被吸附，氧分子留在氣相中，得到氧氣。吸附達(dá)到平衡時(shí)，利用減壓或抽真空將分子篩表面所吸附的氮分子驅(qū)除，恢復(fù)分子篩的吸附能力[1]。為了連續(xù)提供氧氣，裝置通常設(shè)置兩個(gè)或兩個(gè)以上的吸附塔，一個(gè)塔吸附產(chǎn)氧，另一個(gè)塔解吸。真空變壓吸附制氧原理如圖1所示。

　　VPSA oxygen production is a new ambient temperature gas separation technology that uses pressure swing adsorption to produce oxygen from air as raw material. This method is based on the selective adsorption of oxygen and nitrogen components in the air by molecular sieves to separate the air and obtain oxygen, commonly known as vacuum pressure swing adsorption oxygen production method. When air is compressed and passes through an adsorption tower equipped with molecular sieves, nitrogen molecules are preferentially adsorbed, while oxygen molecules remain in the gas phase to obtain oxygen. When adsorption reaches equilibrium, the nitrogen molecules adsorbed on the surface of the molecular sieve are removed by reducing pressure or vacuuming, restoring the adsorption capacity of the molecular sieve. In order to continuously provide oxygen, the device usually sets up two or more adsorption towers, with one tower adsorbing to produce oxygen and the other tower desorbing. The principle of vacuum pressure swing adsorption oxygen production is shown in Figure 1.

　　我司擁有兩套真空變壓吸附制氧裝置，均采用五塔流程，型號(hào)為ZO-7500/80，由國(guó)內(nèi)同一公司設(shè)計(jì)建造，為艾薩爐、轉(zhuǎn)爐、陽(yáng)極爐提供冶煉用氧氣。裝置由羅茨鼓風(fēng)機(jī)、羅茨真空泵、吸附器、儀表控制、電氣控制、切換閥門(mén)、儀表空氣等7個(gè)部分和自控系統(tǒng)組成[2]。變壓吸附法產(chǎn)氧過(guò)程分為吸附、解吸、順向放壓、逆向放壓、均壓5個(gè)階段，每個(gè)塔不斷循環(huán)交替，吸附階段由羅茨鼓風(fēng)機(jī)完成正壓空氣輸送，解吸階段由羅茨真空泵完成廢氣的負(fù)壓抽送，由于產(chǎn)氧的5個(gè)階段塔內(nèi)所需壓力不同，羅茨鼓風(fēng)機(jī)和羅茨真空泵工作壓力通過(guò)16個(gè)氣動(dòng)閥門(mén)自動(dòng)切換來(lái)控制。羅茨鼓風(fēng)機(jī)壓力在0～49 kPa區(qū)間重復(fù)波動(dòng)，羅茨真空泵壓力在-55～0 kPa區(qū)間重復(fù)波動(dòng)，波動(dòng)周期均為1 min[3]。

　　Our company has two sets of vacuum pressure swing adsorption oxygen production units, both using a five tower process, model ZO-7500/80, designed and built by the same domestic company, providing oxygen for smelting in Isa furnaces, converters, and anode furnaces. The device consists of seven parts including Roots blower, Roots vacuum pump, adsorber, instrument control, electrical control, switching valve, instrument air, and an automatic control system. The process of oxygen production by pressure swing adsorption method is divided into five stages: adsorption, desorption, forward pressure release, reverse pressure release, and pressure equalization. Each tower continuously cycles and alternates. The adsorption stage is completed by a Roots blower for positive pressure air transportation, and the desorption stage is completed by a Roots vacuum pump for negative pressure pumping of exhaust gas. Due to the different required pressures inside the tower during the five stages of oxygen production, the working pressures of the Roots blower and Roots vacuum pump are automatically switched through 16 pneumatic valves to control. The pressure of the Roots blower fluctuates repeatedly in the range of 0-49 kPa, and the pressure of the Roots vacuum pump fluctuates repeatedly in the range of -55 to 0 kPa, with a fluctuation period of 1 minute [3].

　　2  羅茨風(fēng)機(jī)振動(dòng)故障情況

　　Vibration fault of Roots blower 2

　　羅茨風(fēng)機(jī)系屬容積回轉(zhuǎn)式風(fēng)機(jī)，屬于旋轉(zhuǎn)式機(jī)械。我司兩套VPSA制氧變壓吸附裝置分別配置2臺(tái)大型羅茨鼓風(fēng)機(jī)和2臺(tái)大型羅茨真空泵，總數(shù)共計(jì)8臺(tái)，是制氧生產(chǎn)最主要的動(dòng)力設(shè)備。羅茨鼓風(fēng)機(jī)和羅茨真空泵技術(shù)參數(shù)如表1所示。

　　The Roots blower system is a volumetric rotary fan and belongs to rotary machinery. Our two VPSA oxygen production pressure swing adsorption units are equipped with 2 large Roots blowers and 2 large Roots vacuum pumps, totaling 8 units, which are the main power equipment for oxygen production. The technical parameters of Roots blower and Roots vacuum pump are shown in Table 1.

　　兩套變壓吸附制氧裝置前后間隔兩年時(shí)間建成，投用后工藝指標(biāo)均能達(dá)到技術(shù)要求。8臺(tái)羅茨風(fēng)機(jī)在交變載荷下運(yùn)行，其振動(dòng)值并不是一個(gè)穩(wěn)定值，一般在4～9.5 mm/s波動(dòng)，只要其最高值和最低值相對(duì)穩(wěn)定即視為正常。但在運(yùn)行7 200 h后，羅茨鼓風(fēng)機(jī)和羅茨真空泵相繼出現(xiàn)振動(dòng)值超標(biāo)的故障，這遠(yuǎn)低于JB/T 8941.1-2014《一般用途羅茨鼓風(fēng)機(jī) 第1部分：技術(shù)條件》[3]中要求的第一次大修前安全運(yùn)行時(shí)間不少于15 000 h的標(biāo)準(zhǔn)。經(jīng)檢查，發(fā)現(xiàn)以下兩種情況：

　　Two sets of pressure swing adsorption oxygen production units were built with a two-year interval between them, and after being put into use, the process indicators can meet the technical requirements. Eight Roots blowers operate under alternating loads, and their vibration values are not stable, usually fluctuating between 4-9.5 mm/s. As long as their highest and lowest values are relatively stable, it is considered normal. But after running for 7200 hours, the Roots blower and Roots vacuum pump successively experienced vibration value exceeding the standard, which is far below the standard of no less than 15000 hours of safe operation time before the first major overhaul required in JB/T 8941.1-2014 "General purpose Roots blower Part 1: Technical conditions" [3]. After inspection, the following two situations were found:

　　第一，風(fēng)機(jī)突發(fā)振動(dòng)聯(lián)鎖跳機(jī)。設(shè)備在運(yùn)行振動(dòng)、溫度、壓力等均較平穩(wěn)的狀態(tài)下，突然毫無(wú)征兆瞬間超過(guò)20 mm/s的振動(dòng)聯(lián)鎖而跳機(jī)，人工無(wú)法盤(pán)動(dòng)轉(zhuǎn)子，從進(jìn)氣口檢查兩葉輪在某個(gè)角度咬死并有碰撞的痕跡。

　　Firstly, the fan suddenly vibrates and interlocks to trip. The equipment suddenly exceeded 20 mm/s vibration interlock without any warning while operating in a relatively stable state of vibration, temperature, pressure, etc., causing the machine to trip. The rotor could not be manually rotated, and the two impellers were checked from the air inlet for biting and collision marks at a certain angle.

　　第二，風(fēng)機(jī)振動(dòng)值持續(xù)升高。設(shè)備在運(yùn)行中溫度、壓力等均較平穩(wěn)的狀態(tài)下，振動(dòng)值呈小幅持續(xù)上升態(tài)勢(shì)，直至觸發(fā)報(bào)警值，停機(jī)后能夠正常盤(pán)車(chē)，從進(jìn)氣口檢查兩葉輪各間隙，除在45°時(shí)間隙偏小外，其他位置間隙均符合技術(shù)要求。

　　Secondly, the vibration value of the fan continues to increase. When the temperature and pressure of the equipment are relatively stable during operation, the vibration value shows a slight and continuous increase until the alarm value is triggered. After shutdown, the equipment can be turned normally. The clearance between the two impellers is checked from the air inlet, and except for a small clearance at 45 °, the clearance at other positions meets the technical requirements.

　　在拆解風(fēng)機(jī)后發(fā)現(xiàn)，第一種故障情況為同步齒輪輪轂發(fā)生松動(dòng)，主、從動(dòng)齒輪發(fā)生錯(cuò)位使兩葉輪相對(duì)嚙合位置改變而導(dǎo)致相撞；第二種情況為襯套與軸頸出現(xiàn)松動(dòng)，襯套內(nèi)孔磨損后晃動(dòng)沖擊不斷加重導(dǎo)致振動(dòng)值持續(xù)升高。按設(shè)備使用說(shuō)明書(shū)中的相關(guān)技術(shù)要求，前述故障需要對(duì)風(fēng)機(jī)進(jìn)行完全解體，在確認(rèn)軸承沒(méi)有損壞的前提下一般通過(guò)更換密襯套和調(diào)整主、從動(dòng)齒輪相對(duì)位置并重新鉸孔定位的方法處理。修理后，風(fēng)機(jī)在試機(jī)和初期運(yùn)行均正常，超過(guò)6個(gè)月后又會(huì)不定時(shí)發(fā)生相同故障，需要5～8天的維修時(shí)間，以至于設(shè)備處于反復(fù)不停的修理當(dāng)中。故障處理期間只能被迫采取運(yùn)行半套裝置的方式降負(fù)荷生產(chǎn)，對(duì)產(chǎn)氧經(jīng)濟(jì)指標(biāo)和下游生產(chǎn)組織造成嚴(yán)重影響，同時(shí)在高噪聲環(huán)境下進(jìn)行設(shè)備搶修作業(yè)，對(duì)維修人員身心健康也造成了一定影響。

　　After disassembling the fan, it was found that the first type of malfunction was the loosening of the synchronous gear hub, which caused the displacement of the main and driven gears, resulting in a change in the relative meshing position of the two impellers and causing a collision; The second scenario is when the bushing and shaft neck become loose, and the inner hole of the bushing wears out, causing the shaking and impact to increase continuously, resulting in a continuous increase in vibration values. According to the relevant technical requirements in the equipment manual, the aforementioned malfunction requires complete disassembly of the fan. Generally, after confirming that the bearings are not damaged, the problem can be resolved by replacing the bushing, adjusting the relative position of the main and driven gears, and repositioning the hinge holes. After repair, the fan operated normally during the trial run and initial operation. However, after more than 6 months, the same malfunction may occur irregularly, requiring 5-8 days of maintenance time, resulting in the equipment being repeatedly repaired. During the fault handling period, only half of the equipment was forced to operate to reduce the load production, which had a serious impact on the oxygen production economic indicators and downstream production organizations. At the same time, equipment repair operations were carried out in a high noise environment, which also had a certain impact on the physical and mental health of maintenance personnel.

　　3  羅茨風(fēng)機(jī)振動(dòng)故障維修改進(jìn)

　　Repair and improvement of vibration faults in Roots blower

　　根據(jù)ARMH型羅茨風(fēng)機(jī)結(jié)構(gòu)，其裝配順序?yàn)槿~輪穿入機(jī)殼→前后墻板安裝→漲圈及襯套安裝→軸承座安裝→軸承安裝→同步齒輪安裝→兩葉輪間隙調(diào)整→同步齒輪定位→甩油盤(pán)及潤(rùn)滑油管安裝→主、副油箱安裝→潤(rùn)滑油泵安裝→油冷卻器安裝→聯(lián)軸器安裝。在風(fēng)機(jī)使用技術(shù)說(shuō)明中，僅對(duì)葉輪與機(jī)殼間隙、葉輪與墻板間隙、兩葉輪“嚙合”間隙作出明確的數(shù)值要求，而其他裝配環(huán)節(jié)只用文字進(jìn)行了一般性說(shuō)明，沒(méi)有具體指標(biāo)[4]。在多次對(duì)風(fēng)機(jī)振動(dòng)故障的處理中，分析過(guò)程中的現(xiàn)象，以采取措施改進(jìn)裝配質(zhì)量。

　　According to the structure of the ARMH Roots blower, the assembly sequence is as follows: impeller insertion into the casing → installation of front and rear wall panels → installation of expansion rings and bushings → installation of bearing seats → installation of bearings → installation of synchronous gears → adjustment of the gap between the two impellers → positioning of synchronous gears → installation of oil slingers and lubricating oil pipes → installation of main and auxiliary oil tanks → installation of lubricating oil pumps → installation of oil coolers → installation of couplings. In the technical instructions for using the fan, only clear numerical requirements are made for the clearance between the impeller and the casing, the clearance between the impeller and the wall panel, and the "meshing" clearance between the two impellers, while other assembly processes are only described in general text without specific indicators [4]. In the handling of fan vibration faults multiple times, analyze the phenomena during the process to take measures to improve assembly quality.

　　3.1漲圈式軸封襯套松動(dòng)

　　3.1 Loose ring type shaft seal liner

　　1）軸封襯套內(nèi)孔與軸頸松動(dòng)。襯套安裝于葉輪主軸的最里處，內(nèi)端面與葉輪端面緊密貼合，在其外圓加工有4個(gè)槽用于安裝高彈性的漲圈，風(fēng)機(jī)運(yùn)行時(shí)葉輪主軸帶動(dòng)襯套同步旋轉(zhuǎn)，漲圈則不隨襯套轉(zhuǎn)動(dòng)，在張力作用下緊貼于墻板孔內(nèi)壁，從而達(dá)到防止氣體外泄的作用，其結(jié)構(gòu)如圖2所示。襯套前端內(nèi)孔銑制有一個(gè)φ14的徑向槽，在與之配合的葉輪主軸相對(duì)應(yīng)位置鉆孔并安裝一顆φ8的圓形銷(xiāo)，其作用是使葉輪主軸的旋轉(zhuǎn)力帶動(dòng)密封襯套同步轉(zhuǎn)動(dòng)。在安裝時(shí)需要將漲圈隨密封襯套同時(shí)裝入主軸和墻板內(nèi)，為減小裝配難度，密封襯套內(nèi)孔與軸頸設(shè)計(jì)為間隙配合，兩者之間有0.10～0.12 mm間隙，密封襯套徑向槽與定位銷(xiāo)有6 mm間隙，在此種配合條件下，密封襯套在交變強(qiáng)沖擊載荷下運(yùn)行一段時(shí)間后很容易出現(xiàn)晃動(dòng)，并敲擊定位銷(xiāo)使其松動(dòng)，對(duì)此，需要圍繞減小配合間隙進(jìn)行改進(jìn)。

　　1) The inner hole of the shaft seal liner and the shaft neck are loose. The liner is installed at the innermost part of the impeller main shaft, with the inner end surface closely attached to the impeller end surface. There are four grooves machined on the outer circumference for installing high elasticity expansion rings. When the fan is running, the impeller main shaft drives the liner to rotate synchronously, while the expansion ring does not rotate with the liner and tightly adheres to the inner wall of the wall panel hole under tension, thereby preventing gas leakage. Its structure is shown in Figure 2. There is a radial groove with a diameter of 14 milled into the inner hole at the front end of the liner. A circular pin with a diameter of 8 is drilled and installed at the corresponding position of the impeller spindle that matches it. Its function is to drive the sealing liner to rotate synchronously with the rotational force of the impeller spindle. During installation, the expansion ring needs to be installed into both the main shaft and the wall panel along with the sealing liner. To reduce assembly difficulty, the inner hole of the sealing liner and the shaft neck are designed to have a clearance fit, with a clearance of 0.10-0.12 mm between the two. The radial groove of the sealing liner has a clearance of 6 mm with the positioning pin. Under this fitting condition, the sealing liner is prone to shaking after running under alternating strong impact loads for a period of time, and knocking the positioning pin can loosen it. Therefore, improvements need to be made to reduce the fitting clearance.

　　2）軸封襯套軸向松動(dòng)。襯套在安裝時(shí)內(nèi)端面緊貼葉輪端面，在軸承裝入后靠鎖緊螺帽將壓緊力傳遞到襯套端面，達(dá)到軸向固定的作用。如果在裝配時(shí)襯套與葉輪、軸承端面與襯套貼合不嚴(yán)密，會(huì)造成軸向壓緊力的假象，在長(zhǎng)時(shí)間沖擊振動(dòng)力的作用下產(chǎn)生軸向間隙而導(dǎo)致襯套松動(dòng)。因此，在安裝襯套前必須把襯套兩個(gè)端面和與之接觸的葉輪端面的毛刺及高點(diǎn)徹底清除，保證接觸面大于75%；軸承經(jīng)加熱裝入主軸和軸承座過(guò)程中，應(yīng)對(duì)稱均勻用力敲擊，通過(guò)聲響辨別推入到位后，立即旋入鎖緊螺母并擰緊，使襯套、軸承與葉輪端面有足夠的軸向壓緊力，彌補(bǔ)軸承冷卻后的收縮量。因襯套安裝時(shí)涂抹了密封膠，從襯套安裝到軸承鎖緊，整個(gè)裝配過(guò)程應(yīng)在2 h內(nèi)完成，以免時(shí)間過(guò)長(zhǎng)密封膠固化產(chǎn)生卡阻導(dǎo)致裝配失敗。

　　2) The shaft seal liner is loose in the axial direction. The inner end face of the liner is tightly attached to the impeller end face during installation, and after the bearing is installed, the clamping force is transmitted to the liner end face by the locking nut, achieving axial fixation. If the liner and impeller, as well as the bearing end face and liner, do not fit tightly during assembly, it will create a false impression of axial compression force, resulting in axial clearance and loosening of the liner under long-term impact vibration force. Therefore, before installing the liner, the burrs and high points on both end faces of the liner and the impeller end face in contact with it must be thoroughly removed to ensure that the contact surface is greater than 75%; During the process of heating and installing the bearing into the main shaft and bearing seat, it should be symmetrically and uniformly struck with force. After being pushed into place through sound recognition, the locking nut should be immediately screwed in and tightened to provide sufficient axial compression force between the bushing, bearing, and impeller end face, compensating for the shrinkage of the bearing after cooling. Due to the application of sealant during the installation of the liner, the entire assembly process from liner installation to bearing locking should be completed within 2 hours to avoid assembly failure caused by prolonged curing of the sealant.

　　3.2

　　three point two

　　兩葉輪撞擊

　　Two impellers collide

　　1）輪轂與軸頸配合接觸差。拆卸同步齒輪輪轂后，軸頸表面有局部黑塊及細(xì)微斑點(diǎn)，與之配合的內(nèi)孔表面對(duì)應(yīng)位置也有相同情況，這說(shuō)明運(yùn)行中輪轂出現(xiàn)了偏擺與軸頸產(chǎn)生拍擊，引起兩葉輪嚙合位置發(fā)生改變而撞擊，此種情況僅靠調(diào)整兩同步齒輪相對(duì)位置無(wú)法徹底解決故障。輪轂與軸頸為1:20的圓錐帶平鍵的設(shè)計(jì)，圓錐配合與圓柱配合相比最大的優(yōu)點(diǎn)是可自動(dòng)定心、配合自鎖性好，裝配體能獲得較高精度的同軸度，但在實(shí)際制造中需要精確的錐度及良好的接觸面積來(lái)保證。經(jīng)使用紅丹粉對(duì)合接觸檢查，接觸面由小端向大端逐漸減少，據(jù)此可以得出，輪轂內(nèi)孔錐度大于主軸錐度，輪轂安裝后在大端配合面存在間隙。從輪轂與主軸配合的結(jié)構(gòu)設(shè)計(jì)分析，兩者錐面配合主要起到保證同步齒輪與葉輪主軸的同軸度作用，同時(shí)分擔(dān)一部分旋轉(zhuǎn)力，主要的旋轉(zhuǎn)力靠平鍵來(lái)傳遞，將錐面配合的位置控制在兩端可保定位的牢固，避免輪轂在沖擊下發(fā)生瓢偏擺動(dòng)。通過(guò)參考類(lèi)似結(jié)構(gòu)高速離心鼓風(fēng)機(jī)設(shè)計(jì)，對(duì)輪轂的內(nèi)錐孔進(jìn)行改造，在通體內(nèi)錐面長(zhǎng)度中間車(chē)制一段長(zhǎng)度80 mm的槽，將錐面打斷去除中間無(wú)效區(qū)域，使兩者接觸面分布在兩端，結(jié)合現(xiàn)場(chǎng)少量的銼配，可以使接觸面達(dá)到75%以上。加工后的輪轂如圖3所示。

　　1) Poor contact between the hub and the journal. After disassembling the synchronous gear hub, there are local black blocks and fine spots on the surface of the shaft neck, and the corresponding position of the inner hole surface that matches it also has the same situation. This indicates that the hub has deviated and the shaft neck has collided during operation, causing the meshing position of the two impellers to change and collide. This situation cannot be completely solved by adjusting the relative position of the two synchronous gears alone. The design of a 1:20 cone with flat keys for the hub and journal has the greatest advantage over cylindrical fitting in that it can automatically center and has good self-locking properties. The assembly can achieve high precision coaxiality, but in actual manufacturing, precise taper and good contact area are required to ensure it. After using red lead powder to check the mating contact, the contact surface gradually decreases from the small end to the large end. Based on this, it can be concluded that the taper of the inner hole of the hub is greater than that of the main shaft, and there is a gap on the mating surface of the large end after the hub is installed. From the structural design analysis of the fit between the wheel hub and the main shaft, the conical fit between the two mainly ensures the coaxiality of the synchronous gear and the impeller main shaft, while sharing a part of the rotational force. The main rotational force is transmitted through the flat key, and the position of the conical fit is controlled at both ends to ensure a firm positioning, avoiding the wheel hub from tilting and swinging under impact. By referring to the design of a high-speed centrifugal blower with a similar structure, the inner taper hole of the wheel hub was modified. A groove with a length of 80 mm was machined in the middle of the inner taper length of the whole body, and the taper was broken to remove the ineffective area in the middle, so that the contact surfaces of the two were distributed at both ends. Combined with a small amount of filing on site, the contact surface could reach more than 75%. The processed wheel hub is shown in Figure 3.

　　2）輪轂與軸圓錐配合過(guò)盈不夠。圓錐配合的配合特征是通過(guò)相互結(jié)合的內(nèi)、外圓錐規(guī)定的軸向位置來(lái)形成間隙或過(guò)盈[5-6]。加大兩者裝配過(guò)盈量可提高圓錐旋轉(zhuǎn)傳動(dòng)力，減小平鍵的傳動(dòng)負(fù)荷，從而平衡傳動(dòng)受力。加大裝配過(guò)盈量可采用對(duì)輪轂加熱的方式來(lái)實(shí)現(xiàn)，同時(shí)也要考慮裝配過(guò)緊對(duì)后期維修拆卸難度的影響；輪轂安裝至軸上后靠鎖緊螺帽進(jìn)行軸向緊固，在用手將輪轂推入軸后，其前端面伸出軸臺(tái)階的長(zhǎng)度為3.5 mm，進(jìn)行熱裝會(huì)減小端面伸出軸臺(tái)的長(zhǎng)度，因此，輪轂增加的推進(jìn)量在3 mm更為合適。

　　2) The interference fit between the wheel hub and the shaft cone is insufficient. The fitting feature of conical fit is to form a gap or interference through the axial position specified by the inner and outer cones that are combined with each other [5-6]. Increasing the interference fit between the two components can improve the cone rotation transmission force, reduce the transmission load of the flat key, and thus balance the transmission force. Increasing the interference fit during assembly can be achieved by heating the wheel hub, while also considering the impact of tight assembly on the difficulty of later maintenance and disassembly; After installing the wheel hub on the shaft, it is tightened axially with a locking nut. After pushing the wheel hub into the shaft by hand, the length of the front end surface protruding from the shaft step is 3.5 mm. Hot fitting will reduce the length of the end surface protruding from the shaft platform. Therefore, an increase in the pushing amount of the wheel hub by 3 mm is more appropriate.

　　4  結(jié)束語(yǔ)

　　4 Conclusion

　　從制氧羅茨風(fēng)機(jī)投用后頻繁發(fā)生振動(dòng)聯(lián)鎖跳機(jī)故障起，經(jīng)歷2年多時(shí)間對(duì)故障點(diǎn)的持續(xù)查找、分析和維修裝配方法的不斷改進(jìn)，最終無(wú)故障運(yùn)行時(shí)間達(dá)到45 000 h以上，比JB/T 8941.1-2014《一般用途羅茨鼓風(fēng)機(jī) 第1部分：技術(shù)條件》中要求的第一次大修前安全運(yùn)行時(shí)間標(biāo)準(zhǔn)提高了2倍，檢修原因轉(zhuǎn)變?yōu)橐詽q圈和軸承部件的使用壽命為主，有利于設(shè)備大修的策劃。從根源上增強(qiáng)了羅茨風(fēng)機(jī)對(duì)變壓吸附制氧裝置特殊工況的適應(yīng)性，有效促進(jìn)了作業(yè)率和經(jīng)濟(jì)指標(biāo)的提升。

　　Since the frequent occurrence of vibration interlock tripping faults in the oxygen producing Roots blower after its commissioning, after more than 2 years of continuous search, analysis, and improvement of maintenance and assembly methods, the final fault free operation time has reached over 45000 hours, which is twice the safety operation time standard required in JB/T 8941.1-2014 "General purpose Roots blower Part 1: Technical conditions" before the first major overhaul. The maintenance reason has shifted to the service life of the expansion ring and bearing components, which is conducive to the planning of equipment major repairs. From the root, the adaptability of Roots blower to the special working conditions of pressure swing adsorption oxygen production unit has been enhanced, effectively promoting the improvement of operation rate and economic indicators.

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