阅读说明：本技术 一种加工孔中心线偏移量检测装置及检测方法 (A kind of processing centerline hole offset detector and detection method ) 是由 金静 曹朋 马顺利 张永红 陶彩玲 何朝霞 陈苏惠 徐志成 于 2019-08-30 设计创作，主要内容包括：本发明公开了一种加工孔中心线偏移量检测装置及检测方法,包括测量销,测量销配合安装在加工孔内；测量基座配合固定在基准圆弧面上,滑动导轨设置在测量基座上；滑动导轨包括平行设置的第一导轨基准面和第二导轨基准面,测量支架的下端与第一或第二导轨基准面滑动连接,检测表设置在测量支架的上端,测量杠杆活动设置在测量支架上；测量杠杆的下端与测量销接触,上端与检测表连接；本发明将加工孔的中心线转化为测量销的中心轴线,将基准圆弧面的垂直中心线转化为两个平行的导轨基准面,结合测量基座、测量杠杆及检测表,能够直观得到加工孔中心线对基准圆弧表面垂直中心线平行偏移量；装置结构简单,操作方法方便,结果准确且能够实现快速测量。(The invention discloses a kind of processing centerline hole offset detector and detection method, including measurement pin, measurement pin is fitted in processing hole；Measurement pedestal cooperation is fixed on benchmark arc surface, and slide rail setting is on measurement pedestal；Slide rail includes the first guide rail datum level disposed in parallel and the second guide rail datum level, and the lower end and first or second guide rail datum level for measuring bracket are slidably connected, and the upper end of measurement bracket is arranged in detection table, and measurement lever is movably arranged on measurement bracket；The lower end and measurement pin contacts, upper end for measuring lever are connect with detection table；The present invention converts the center line for processing hole to the central axis of measurement pin, two parallel guide rail datum levels are converted by the vertical center line of benchmark arc surface, in conjunction with measurement pedestal, measurement lever and detection table, processing centerline hole can be intuitively obtained to benchmark arc-shaped surface vertical center line parallel offset amount；Apparatus structure is simple, and operating method is convenient, as a result accurate and can be realized rapid survey.)

1. a kind of processing centerline hole offset detector, which is characterized in that including measurement pin (1), measurement pedestal (2), slide Dynamic guide rail (3), measurement lever (4), measurement bracket (5) and detection table (6)；Measurement pin (1) is fitted to front housing basic circle In the processing hole of cambered surface, the axis of measurement pin (1) is overlapped with the center line in processing hole；Measurement pedestal (2) cooperation is fixed on preceding machine On the benchmark arc surface of casket, slide rail (3) is fixed at the top of measurement pedestal (2)；Slide rail (3) includes setting in parallel The the first guide rail datum level (31) and the second guide rail datum level (32) set, the first guide rail datum level (31) and the second guide rail datum level (32) two sides of measurement pin (1) are separately positioned on, the first guide rail datum level (31) and the second guide rail datum level (32) are and benchmark The vertical central plane of arc surface is parallel；Measure lower end and the first guide rail datum level (31) or the second guide rail datum level of bracket (5) (32) it is slidably connected, measurement bracket (5) can be parallel along the first guide rail datum level (31) or the second guide rail datum level (32) respectively It is mobile；Table (6) setting is detected in the upper end of measurement bracket (5)；Measurement lever (4) is movably arranged in measurement bracket (5), measurement The measuring staff of the lower end of lever (4) and the outer circumference face contact of measurement pin (1), the upper end and detection table (6) that measure lever (4) connects It connects.

2. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that further include resetting Spring (7), reset spring (7) is horizontally disposed, and one end of reset spring (7) is connect with measurement bracket (5), the other end and measurement thick stick The upper end of bar (3) connects.

3. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that further include fastening One end of mechanism (8), retention mechanism (8) is fixedly connected with measurement pedestal (2)；Retention mechanism (8) include securing bracket (81) and Fastening bolt (82), the upper end of securing bracket (81) are fixed at measurement pedestal front end, and the lower end of securing bracket (81) is downward Setting；Fastening bolt (82) level is threaded through on securing bracket (81), fastening bolt (82) end and the fixed company of front housing part It connects.

4. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that measurement pedestal It (2) include base body (21), base stand location block (22), positioning pin (23) and measurement window (24), base body (21) uses Slab construction, base stand location block (22) setting is in base body (21) lower part, base stand location block (22) and front housing benchmark circular arc The upper opening in face is cooperatively connected；The left and right ends of base body (21) are symmetrical arranged there are two location hole, and positioning pin (23) is matched It closes and is arranged in positioning hole, base body (21) is fixed on front housing by positioning pin (23)；Base body is set on (21) It sets measurement window (24), the top of measurement pin (1) is arranged in measurement window (24), and the lower end of measurement lever (4) passes through measurement window (24) it is contacted with measurement pin (1).

5. a kind of processing centerline hole offset detector according to claim 4, which is characterized in that base body (21) a U-shaped opening slot, the part installation of U-shaped opening groove location size and front housing upper surface are respectively set at left and right sides of Bolt cooperation.

6. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that measurement lever It (4) include measurement arm (41) and rotating dog (42), measurement arm (41) is movably arranged on measurement bracket (5) by rotating dog (42) On；Rotating dog (42) setting connects in the intermediate position of measurement arm (41), the measuring staff of the upper end and detection table (6) that measure arm (41) It connects, the lower end of measurement arm (41) is contacted with measurement pin (1).

7. a kind of processing centerline hole offset detector according to claim 6, which is characterized in that measurement lever It (4) further include gauge head (43), gauge head (43) setting is in the lower end of measurement arm (41), the outside circle of gauge head (43) and measurement pin (1) All face contacts.

8. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that measurement bracket It (5) include L-type support (51) and guide rail boss (52), L-type support (51) setting is in the top of measurement pedestal (2), L-type support (51) horizontal segment is close to setting with the upper surface of measurement pedestal (2)；The level in L-type support (51) is arranged in guide rail boss (52) The end of section, guide rail boss (52) are close to sliding with the first guide rail datum level (31) or the cooperation of the second guide rail base face (32) and are set It sets；Detection table (5) is fixed at the upper end of L-type support (51) vertical section, measures the level of lever (4) and L-type support (51) Section is flexibly connected.

9. a kind of processing centerline hole offset detector according to claim 1, which is characterized in that detection table (6) Measuring staff it is horizontally disposed, detection table (6) uses dial gauge or amesdial.

10. a kind of processing centerline hole offset checking method, which is characterized in that using described in claim 1-9 any one Processing centerline hole offset detector, comprising the following steps:

Measurement pin (1) is fitted in the processing hole of front housing by step 1；

Measurement pedestal (2) cooperation is fixed on the benchmark arc surface of front housing by step 2；

Step 3, the lower end that will measure bracket (5) and the first guide rail datum level (31) cooperate, along the first guide rail datum level (31) Traverse measurement bracket (5), the maximum tabular value of record detection table (6), is denoted as the first maximum deviation value L1；

Step 4, the lower end that will measure bracket (5) and the second guide rail datum level (32) cooperate, along the second guide rail datum level (32) Traverse measurement bracket (5), the maximum tabular value of record detection table (6), is denoted as the second maximum deviation value L2；

Step 5, using the first maximum deviation value L1 and the second maximum deviation value L2, processing centerline hole offset inspection is calculated Survey device.

Technical field

The invention belongs to front housings to process centerline hole offset technical field, in particular to a kind of processing centerline hole is inclined The detection device and detection method of shifting amount.

Background technique

Front housing is one of domestic high thrust, the main component of gas turbine jet formula aero-engine, is in engine Large complicated shell casing part, function are to install the front support roller bearing, central transmission casing, turbine of compressor Motivation, radome fairing, accessory drive gear and inlet guide vane of compressor etc., front housing be compressor rotor supporting point and The starting point of accessory drive system, the part maximum gauge φ 1300mm of front housing, more than 170 pedestal circles of surface distribution of front housing Cambered surface is provided with horizontal shoulder between two neighboring benchmark arc surface, and the bottom of each benchmark arc surface is provided with a processing Hole；In practical set, therefore, to assure that process parallel offset amount between the center line in hole and benchmark arc surface vertical center line not Preset rules value can be greater than；Currently, generally use each processing centerline hole of three-dimensional coordinates measurement it is vertical with benchmark arc surface in The measurement of heart line parallel offset, detecting instrument figure is larger, and detecting instrument required precision is higher, and detection efficiency is low, detection money Source holding time is longer.

Summary of the invention

For the technical problems in the prior art, the present invention provides a kind of detections of circular hole disalignment amount Device and detection method, to solve to detect the vertical centre for processing centerline hole and benchmark arc surface on front housing in the prior art When parallel offset amount between line, detecting instrument is more demanding, and detection efficiency is low and the detection longer skill of resource occupation time Art problem.

In order to achieve the above objectives, the technical solution adopted by the present invention are as follows:

The present invention provides a kind of processing centerline hole offset detector, including measurement pin, measurement pedestal, sliding are led Rail, measurement lever, measurement bracket and detection table；Measurement pin is fitted in the processing hole of front housing benchmark arc surface, measurement The axis of pin is overlapped with the center line in processing hole；Measurement pedestal cooperation is fixed on the benchmark arc surface of front housing, slide rail It is fixed at the top of measurement pedestal；Slide rail includes the first guide rail datum level disposed in parallel and the second guide rail benchmark Face, the first guide rail datum level and the second guide rail datum level are separately positioned on the two sides of measurement pin, the first guide rail datum level and second Guide rail datum level is parallel with the vertical central plane of benchmark arc surface；Measure lower end and the first guide rail datum level or second of bracket Guide rail datum level is slidably connected, and measurement bracket can be moved in parallel along the first guide rail datum level or the second guide rail datum level respectively； The upper end of measurement bracket is arranged in detection table；Measurement lever is movably arranged on measurement bracket, measures lower end and the measurement of lever The outer circumference face contact of pin, the upper end for measuring lever are connect with the measuring staff of detection table.

It further, further include reset spring, reset spring is horizontally disposed, and one end of reset spring and measurement bracket connect It connects, the other end is connect with the upper end of measurement lever.

It further, further include retention mechanism, one end of retention mechanism is fixedly connected with measurement pedestal；Retention mechanism includes Securing bracket and fastening bolt, the upper end of securing bracket are fixed at measurement pedestal front end, and the lower end of securing bracket is to dividing into It sets；Fastening bolt level is threaded through on securing bracket, and fastening bolt end is fixedly connected with front housing part.

Further, measurement pedestal includes that base body, base stand location block, positioning pin and measurement window, base body are adopted With slab construction, the setting of base stand location block is opened on base body lower part, base stand location block and the top of front housing benchmark arc surface Mouth is cooperatively connected；The left and right ends of base body are symmetrical arranged there are two location hole, and detent fit setting is led in positioning hole It crosses positioning pin base body is fixed on front housing；Measurement window is set on base body, and measurement pin is arranged in measurement window Top, the lower end for measuring lever pass through measurement window and measurement pin contacts.

Further, be respectively set a U-shaped opening slot at left and right sides of base body, U-shaped opening groove location size with The part installation bolt cooperation of front housing upper surface.

Further, measurement lever includes measurement arm and rotating dog, and measurement arm is movably arranged on measurement branch by rotating dog On frame；The intermediate position of measurement arm is arranged in rotating dog, and the upper end for measuring arm is connect with the measuring staff of detection table, measures the lower end of arm With measurement pin contacts.

Further, measurement lever further includes gauge head, and the lower end of measurement arm, the outside of gauge head and measurement pin is arranged in gauge head Circumference contact.

Further, measurement bracket includes L-type support and guide rail boss, and the top of measurement pedestal, L is arranged in L-type support The horizontal segment of type bracket is close to setting with the upper surface of measurement pedestal；The end of the horizontal segment of L-type support is arranged in guide rail boss, Guide rail boss is close to sliding setting with the first guide rail datum level or the cooperation of the second guide rail base face；Detection table is fixed at L-type The upper end of bracket vertical section, measurement lever are flexibly connected with the horizontal segment of L-type support.

Further, the measuring staff for detecting table is horizontally disposed, and detection table uses dial gauge or amesdial.

The present invention also provides a kind of processing centerline hole offset checking methods, comprising the following steps:

Measurement pin is fitted in the processing hole of front housing by step 1；

Measurement pedestal cooperation is fixed on the benchmark arc surface of front housing by step 2；

Step 3 cooperates the lower end for measuring bracket and the first guide rail datum level, along the first guide rail datum level traverse measurement Bracket, the maximum tabular value of record detection table, is denoted as the first maximum deviation value L1；

Step 4 cooperates the lower end for measuring bracket and the second guide rail datum level, along the second guide rail datum level traverse measurement Bracket, the maximum tabular value of record detection table, is denoted as the second maximum deviation value L2；

Step 5, using the first maximum deviation value L1 and the second maximum deviation value L2, processing centerline hole offset is calculated Amount detecting device.

Compared with prior art, the invention has the benefit that

The present invention provides a kind of processing centerline hole offset detectors, will be processed in hole by the way that measurement pin is arranged Heart line is converted into the central axis of measurement pin, converts two parallel guide rail benchmark for the vertical center line of benchmark arc surface Face can intuitively obtain adding on aero-engine front housing benchmark arc surface in conjunction with measurement pedestal, measurement lever and detection table Work centerline hole is to benchmark arc-shaped surface vertical center line parallel offset amount；Structure of the detecting device is simple, easy to operate, detection knot Fruit is accurate and can be realized rapid survey.

Further, by the way that reset spring is arranged, restoring force is provided in real time for measurement lever, it is ensured that detect the detected value of table The true measurement of reflection measurement lever.

Further, measurement pedestal front end be arranged retention mechanism, using retention mechanism will measure pedestal and it is to be measured before Casing part is fixedly connected, and realizes the accurate positionin to measurement pedestal, is avoided and is measured pedestal generation radial direction in measurement process Play, it is ensured that the accuracy of measurement result.

Further, base stand location block and positioning pin are set using in the bottom of base body, realize base body with The axial of pedestal arc surface is accurately positioned, and avoids and measures pedestal generation axial float in measurement process；By the way that measurement window is arranged Mouthful, convenient for real-time observation of the survey crew in measurement process to measurement lever and measurement pin contact condition, it is ensured that measurement result Accuracy.

Further, by the way that a U-shaped opening slot, U-shaped opening groove location are respectively set at left and right sides of base body The installation bolt cooperation of the part of size and front housing upper surface, is fitted on benchmark arc surface convenient for base body.

Further, arm will be measured using rotating dog to be movably connected on measurement bracket, branch of the rotating dog as measurement arm Point forms lever as a result, using lever principle, the offset of measurement pin can be obtained, measurement process is intuitively quick, measurement result Accuracy is high.

Further, detection table uses dial gauge or amesdial, when measurement lever is moved along measurement pin circumference two sides, from The offset of processing centerline hole can be obtained in reading on the dial plate of dial gauge or amesdial.

The present invention also provides a kind of detection methods for processing centerline hole offset, are analyzed by dimension conversion, utilize Lever principle is realized to processing centerline hole on aero-engine front housing benchmark arc surface to benchmark arc-shaped surface vertical centre Line parallel offset amount measures, and can satisfy the requirement of its technique, the detectability with fast accurate, can reach it is quick, Accurate purpose can promote detection efficiency, improve Detection accuracy, meet part batch production testing requirements.

Detailed description of the invention

Fig. 1 is detection device overall structure diagram of the present invention；

Fig. 2 is the measurement pin structural schematic diagram in detection device of the present invention；

Fig. 3 is the measurement pedestal and sliding rail structure schematic diagram in detection device of the present invention；

Fig. 4 is the pedestal and slide rail top view in detection device of the present invention；

Fig. 5 is detection device using process diagram of the present invention, wherein figure a is left side instrumentation plan, figure b is Right side instrumentation plan；

Fig. 6 is the partial structural diagram of front housing in the present invention；

Fig. 7 is the A of front housing in the present invention to partial sectional view.

Wherein, 1 measurement pin, 2 measurement pedestals, 3 slide rails, 4 measurement levers, 5 measurement brackets, 6 detection tables, 7 reset bullet Spring, 8 retention mechanisms, 9 processing holes, 10 benchmark arc surfaces；21 base bodies, 22 base stand location blocks, 23 positioning pins, 24 measurement windows Mouthful；31 first guide rail datum levels, 32 second guide rail datum levels；41 levers, 42 rotating dogs, 43 gauge heads；51L type bracket, 52 guide rails Boss；81 securing brackets, 82 fastening bolts.

Specific embodiment

Invention is further described in detail with reference to the accompanying drawings and detailed description.

With reference to shown in attached drawing 1-5, a kind of detection device for processing centerline hole offset of the present invention, including measurement Pin 1, measurement pedestal 2, slide rail 3, measurement lever 4, measurement bracket 5, detection table 6, reset spring 7 and retention mechanism 8；

Measurement pin 1 is fitted in the processing hole 9 of front housing, the central axis of measurement pin 1 and the center line in processing hole It is overlapped, the lower end installation of measurement pin 1 is protruded into the processing hole 9 of front housing, and the upper end of measurement pin 1 is exposed outside processing hole 9, measurement The aperture in the size of pin 1 and processing hole 9 is that small―gap suture cooperates, it is ensured that measurement pin 1 is mounted in processing hole without shaking, loosening or inclined Tiltedly；Measurement pedestal 2 is equipped on benchmark arc surface 10, is provided with horizontal shoulder between two neighboring benchmark arc surface 10, The left and right ends of measurement pedestal 2 are fixedly connected with the horizontal shoulder of 10 two sides of benchmark arc surface respectively；Slide rail 3 is fixedly installed On the top of measurement pedestal 3, slide rail 3 includes the first guide rail datum level 31 disposed in parallel and the second guide rail datum level 32, First guide rail datum level 31 and the second guide rail datum level 32 are separately positioned on the two sides of measurement pin 1,31 He of the first guide rail datum level Second guide rail datum level 32 is parallel with the vertical central plane of benchmark arc surface 10, and the upper of measurement pedestal 2 is arranged in measurement bracket 5 Portion, measurement support 5 lower end be slidably connected with the first guide rail datum level 31 or the second guide rail datum level 32, when measurement bracket 5 and When first guide rail datum level 31 is slidably connected, measurement bracket 5 can be realized along 31 parallel sliding of the first guide rail datum level to measurement The measurement of 1 left side offset of pin；When measuring bracket 5 and the second guide rail datum level 32 and being slidably connected, measuring bracket 5 can be along the Two guide rail datum levels, 32 parallel sliding realizes the measurement to 1 right side offset of measurement pin.Measurement bracket 5 is arranged in detection table 6 The measuring staff of upper end, detection table 6 is horizontally disposed；Measurement lever 4 is movably arranged on measurement bracket 5, measures lower end and the survey of lever 4 The outer circumference face contact of pin 1 is measured, the upper end for measuring lever 4 is connect with the measuring staff of detection table 6.

Measuring pedestal 2 includes base body 21, base stand location block 22, positioning pin 23 and measurement window 24, base body 21 For slab construction, base stand location block 22 is fixed at the lower surface of base body 21, base stand location block 22 and front housing benchmark The upper opening of arc surface 10 is cooperatively connected；The left and right ends of base body 21 are symmetrical arranged there are two location hole, and location hole leans on The rear end face setting of nearly base body 21；Positioning pin 23, which runs through, to be arranged in positioning hole, and the inner circle of lower end and front housing is fixed Base body 21, is fixedly connected by connection by positioning pin 23 with front housing；Realize the axial direction of base body 21 Yu front housing It is accurately positioned, avoids and measure the generation axial float of pedestal 2 in measurement process.Measurement window 23 is arranged on base body 21, The top of measurement pin 1 is arranged in measurement window 24, and the lower end of measurement lever 4 contacts with measurement pin 1 after measurement window 24, leads to Cross real-time sight of the setting measurement window 24 convenient for survey crew in measurement process to measurement lever 4 and 1 contact condition of measurement pin It examines, it is ensured that the accuracy of measurement.

Due to being provided with part installation bolt on the horizontal shoulder of front housing, the left and right sides of base body 21 is respectively set The part installation bolt cooperation of one U-shaped opening slot, U-shaped opening groove location size and front housing upper surface, is convenient for base body 21 are fitted on benchmark arc surface.

Measuring lever 4 includes measurement arm 41, rotating dog 42 and gauge head 43, and measurement arm 41 is movably arranged on by rotating dog 42 It measures on bracket 5；The intermediate position of measurement arm 41, fulcrum of the rotating dog 42 as measurement lever 4 is arranged in rotating dog 42；Rotation When pin 42 is arranged at the midpoint of measurement arm 41, measurement lever 4 forms equidistant lever, therefore, the measurement that detection table 6 measures The amount of movement of 41 upper end of arm is the offset of measurement pin 1；Measurement arm 41 can be rotated around rotating arm 42；Measure the upper end of arm 41 It is connect with the measuring staff of detection table 6, the lower end of measurement arm 41 is arranged in gauge head 43, and gauge head 43 and the outer circumference face of measurement pin 1 connect Touching.

Measuring bracket 5 includes L-type support 51 and guide rail boss 52, and the top of measurement pedestal 2, L-type is arranged in L-type support 51 The horizontal segment of bracket 51 is close to setting with the upper surface of base body 21；The horizontal segment of L-type support 51 is arranged in guide rail boss 52 End, guide rail boss 52 and the first guide rail datum level 31 or the cooperation of the second guide rail base face 32 are close to sliding and are arranged；Detect table 5 It is fixed at the upper end of 51 vertical section of L-type support, measurement lever 4 is flexibly connected with the horizontal segment of L-type support 51；L-type support 51 along the first guide rail datum level 31 or the second guide rail base face 32 when moving, and drives the lower end of measurement lever 4 in the outer of measurement pin 1 Moved on the circumference of side, thus on 1 two sides periphery of activity measurement pin same section relative displacement.

The measuring staff for detecting table 6 is horizontally disposed, and detection table 6 uses dial gauge or amesdial.

Reset spring 7 is horizontally set between measurement lever 4 and measurement bracket 5, one end of reset spring 7 and measurement lever The other end of 4 upper end connection, reset spring 7 is connect with measurement bracket 5, and reset spring 7 is used to provide reply to measurement lever 4 Power；When measuring the movement of 4 lower end edge measurement pin of lever, 1 outer arc face, according to the 1 radial dimension of change in outer arc face of measurement pin Change, restoring force is generated to the upper end of measurement lever 4, it is ensured that the measurement result accuracy of detection table 6.

Retention mechanism 8 is fixed at the front end of measurement pedestal 2, and 8 upper end of retention mechanism is connect with base body 21, fastens The lower end of mechanism 8 is connect with front housing ontology, is that measurement pedestal 2 provides radial positioning by retention mechanism 8.Retention mechanism 8 wraps Securing bracket 81 and fastening bolt 82 are included, the front end of base body 21 is arranged in by fastener for the upper end of securing bracket 81, tightly The lower end of clamped frame 81 is down-set, and 82 level of fastening bolt is threaded through on securing bracket 81, the axis and base of fastening bolt 82 The end of the horizontal center line of director circle cambered surface 10, fastening bolt 82 is fixedly connected with front housing part, will be surveyed using fastening bolt Amount pedestal is fixedly connected with front housing part to be measured, is realized the accurate positionin to measurement pedestal, is avoided in measurement process and survey It measures pedestal and radial-play occurs, it is ensured that the accuracy of measurement result.

Working principle:

A kind of detection device for processing centerline hole offset of the present invention, according to machine before aero-engine compressor Processing centerline hole on the porous benchmark arc surface of casket wants the measurement of benchmark arc surface surface vertical center line parallel offset amount It asks, in conjunction with measuring point design feature, using Reference Transforming principle, the measurement pin matched with processing hole is made, by measurement pin Cooperation is fixed in processing hole, using the center line in the central axis substitution processing hole of measurement pin；Production and benchmark circular arc Two guide rail datum levels being parallel to each other are arranged on measurement pedestal, using by benchmark arc surface in the measurement pedestal of face cooperation Vertical center line is converted to two basic rack faces being parallel to each other.When measurement, measurement pin is installed in processing hole, using survey Pedestal, measurement lever and the cooperation for detecting table are measured, respectively along two guide rail datum level translation measurement pedestals, and then drives measurement thick stick The measurement to measurement pin outer arc face different location offset is realized in the movement of bar, respectively two maximums of record detection table Processing centerline hole and benchmark arc surface can be calculated according to lever principle using two maximum offsets in offset value The size of vertical centre line deviation；When measurement lever is that equidistant lever is, two maximum offsets difference be to process hole Disalignment amount, the difference of two maximum offsets it is positive and negative, reflect processing centerline hole relative datum arc surface offset Direction.By the way that in the front end of base body setting retention mechanism, base body is connect with front housing fastening parts in the present invention, Realize the axially position of base body and front housing；By the way that positioning pin is arranged in the rear end of base body, pedestal sheet is realized The radial positioning of body and front housing；The setting triangular in shape on base body of retention mechanism and positioning pin provides for measurement pedestal Accurately location condition avoids the play that pedestal is measured in measurement process, it is ensured that the accuracy of measurement result.