CN204188129U - A kind of axiality detection device for dissimilar brake drum - Google Patents

Abstract

The utility model discloses a coaxiality detection device for different types of brake drums, which belongs to the technical field of detection of auto parts. The coaxiality detection device of the utility model is equipped with a rolling support seat at the center of the workbench, and an inner hole positioning assembly is arranged in the support seat, and a front positioning plate and a rear positioning plate are arranged in parallel on both sides of the workbench. The bar assembly is arranged on the flap hinged with the rear positioning plate, and the positioning pin on the flap cooperates with the positioning needle sleeve on the top of the front positioning plate to locate the flap. The utility model improves the detection efficiency under the premise of ensuring the detection accuracy through the cooperative use of the inner hole positioning assembly and the measuring rod assembly on the flap, has low requirements on the detection environment, reduces the production cost, and realizes the brake drum. 100% complete online inspection, and can inspect different types of brake drums by replacing the inner hole positioning posts of different sizes.

Description

A coaxiality detection device for different types of brake drums

technical field

The utility model relates to the technical field of auto parts detection, in particular to a coaxiality detection device for different types of brake drums.

Background technique

Automobile brake drum is an important safety part of automobile braking. The quality of automobile brake drum directly affects the driving safety of the automobile, and is related to the safety of drivers and goods and property. Therefore, each automobile manufacturer pays attention to the safety of automobile brake drum Quality has very strict testing and control standards. At present, domestic axle manufacturers mainly use three-coordinate testing for the coaxiality and other shape and position tolerances of brake drums. Because the three-coordinate inspection tool is expensive and has high requirements for the use environment, it cannot meet 100% online measurement in actual production. , can only achieve random inspection by batch. There are also some small companies that use improved brake drum inspection tools, but these inspection tools have poor accuracy, and most of them are tested for the same type of brake drums, which cannot meet the testing requirements for different types of brake drums. Therefore, it is very necessary and urgent to design an on-line detection device capable of detecting various types of brake drums with high precision and low cost.

After searching, some technical solutions about the detection of automobile brake drums have been disclosed. Chinese patent application number: 201320001194.8, announcement date: June 26, 2013, the name of the invention is: an auxiliary device for detecting the beating of the brake drum assembly, the right-angle support and the support bearing in the patent scheme are respectively fixed On the planes of two different heights of the base, through the combination of different support shafts and bushings, the detection of the runout of different models of front brake drum assemblies can be satisfied. While testing, secure the front wheel brake assembly by tightening the planetary handle. Turn the handwheel, the handwheel drives the screw to rotate, the movement makes the slider move up and down relative to the guide rail through the transmission, and the detection is completed through the compound movement of the dial indicator moving up and down and the workpiece rotating. The patented solution is to detect the assembled brake drum assembly, and its influencing factors include the cooperation between the outer ring of the bearing and the hub and the manufacturing accuracy of the single piece of the brake drum, which cannot meet the detection requirements for the coaxiality of the brake drum. Accuracy cannot be guaranteed.

Chinese patent application number: 201320808013.2, announcement date: April 30, 2014, the name of the invention is: a brake drum full runout inspection tool, the application discloses a brake drum full runout inspection tool, including a workbench , measuring equipment, brake drum, and the shaft head installed on the workbench, the hub and the hub bearing are assembled on the shaft head, the brake drum is placed on the wheel hub, and the guide rail bracket is also installed on the workbench. One side of the guide rail bracket is installed with a linear guide rail pair, the linear guide rail pair is provided with a sliding seat, a fixed frame is connected to the sliding seat, the end of the fixed frame is equipped with the measuring device, and the measuring device extends into the brake drum inside and against the inner circle of the brake drum. There are deficiencies in the structure of this patent scheme, it is not an ideal solution, and it needs to be further improved.

Utility model content

1. The technical problems to be solved by the utility model

The purpose of the utility model is to overcome the deficiencies in the prior art, such as high cost, difficult maintenance, cumbersome calibration procedures, low precision of ordinary inspection tools, and inability to realize multi-variety brake drum detection in the prior art. The coaxiality detection device of the brake drum realizes 100% online complete detection of the brake drum, and has low requirements for the detection environment and high detection accuracy, and can detect different types of brakes by replacing the inner hole positioning columns of different sizes. Drums are tested.

2. Technical solution

In order to achieve the above object, the technical solution provided by the utility model is:

A coaxiality detection device for different types of brake drums of the utility model includes a worktable, and also includes a rolling support seat, an inner hole positioning assembly, a flap and a measuring rod assembly. A rolling support seat is installed in the center, and a front positioning plate and a rear positioning plate are arranged in parallel on both sides of the worktable. The top of the rear positioning plate is hinged with one end of the flap, and the other end of the flap is equipped with a positioning pin The upper end of the front positioning plate is equipped with a positioning needle sleeve, and the flip plate and the front positioning plate are positioned and connected through the cooperation between the positioning pin and the positioning needle sleeve;

The measuring rod assembly is installed on the flip plate for detecting the brake drum to be tested;

The inner hole positioning assembly is installed on the workbench and is used for positioning the inner hole of the brake drum to be tested.

As a further improvement of the utility model, the measuring rod assembly includes a dial indicator, a dial indicator fixing clip, an adjusting guide rod, a locking screw, a measuring rod pin, a table seat and a measuring rod, wherein: One side is provided with a measuring rod mounting hole vertical to the end face of the flap. A meter base is installed in the measuring rod mounting hole, and the shoulder of the meter base is fixedly connected with the flap by bolts. The meter seat is set on the adjusting guide rod. The outer circumference, and the watch base is slidingly connected with the adjusting guide rod, and a threaded hole is opened on the upper side of the watch base, and the locking screw fixes the adjusting guide rod through the threaded hole; the upper end of the adjusting guide rod is equipped with a dial gauge fixing clip, The dial indicator is installed on the adjustment guide rod through the dial indicator fixing clip; a through hole is provided inside the adjustment guide rod, a measuring rod is installed in the through hole, and a pin hole is opened in the middle of the measuring rod. The measuring rod pin passes through the pin hole so that the measuring rod is hinged with the adjusting guide rod, one end of the measuring rod is in contact with the contact of the dial indicator, and the other end of the measuring rod is set in an L shape extending out from the lower end of the adjusting guide rod , and a spherical contact is provided on the head of the L-shaped end of the measuring rod, and the spherical contact is used to contact the braking surface of the brake drum to be detected.

As a further improvement of the utility model, the inner hole positioning assembly includes a positioning pin and an inner hole positioning column, wherein: one end of the positioning pin is installed with a bearing, and the inner hole positioning column is sleeved on the outer ring of the bearing Above; the first positioning hole and the second positioning hole are opened on the workbench, and the first positioning hole and the second positioning hole are symmetrically distributed on the same diameter line of the rolling support seat, and the positioning pin is installed on the second A positioning hole and a second positioning hole, and the positioning pin is clearance-fitted with the first positioning hole and the second positioning hole to form a detachable inner hole positioning assembly.

As a further improvement of the utility model, the adjustment guide rod is also equipped with an adjustment pin and a spring guide pin, and the adjustment pin is installed on the side opposite to the dial indicator at the upper end of the adjustment guide rod. The spring guide pin is installed on the same side as the dial indicator at the upper end of the adjustment guide rod, and the end of the spring guide pin towards the measuring rod is equipped with a spring, and the pressure of the spring on the measuring rod is changed by adjusting the spring guide pin.

As a further improvement of the utility model, a handle is provided on the end face of the flap located at one end of the front positioning plate; a rotating baffle is installed on the upper surface of the hinged end of the flap and the rear positioning plate, and a rotating baffle is formed on both sides of the rotating baffle. Knuckle, one side of the knuckle is fixedly connected to the turnover plate by screws, and the apex of the knuckle is located on the same plane as the outer surface of the rear positioning plate.

As a further improvement of the utility model, the rolling support seat includes an end surface rolling seat, a steel ball and a rolling base. On the stage, the lower side of the end surface rolling seat and the upper side of the rolling base are provided with annular grooves, and steel balls are arranged in the annular grooves to make the end surface rolling seat rotate around the central axis of the rolling base.

3. Beneficial effect

Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:

(1) A coaxiality detection device for different types of brake drums of the present invention, one end of the measuring rod in the measuring rod assembly is in contact with the braking surface of the brake drum, and the other end is in contact with the dial indicator, through Using the lever structure principle to display the coaxiality detection data value of the brake drum braking surface on the dial indicator, the structure is simple, the detection accuracy is high, and the use cost is low; by adjusting the measuring rod assembly and replacing the inner hole with different outer diameters The positioning column can detect brake drums of different types and sizes, realizing the universal measurement of multiple types of brake drums.

(2) A coaxiality detection device for different types of brake drums of the present invention, the inner hole positioning assembly is installed in the first positioning hole and the second positioning hole symmetrically distributed on the same radial line, In addition, the inner hole positioning column in the inner hole positioning assembly can rotate around the positioning pin, which meets the requirements of rotation detection, enables the brake drum to be detected to be positioned in the radial direction, and further improves the detection accuracy;

(3) A coaxiality detection device for different types of brake drums of the present invention, steel balls are installed in the annular groove of the end surface rolling seat, so that the end surface rolling seat can rotate around the central axis of the rolling base, and can Directly observe the numerical change from the dial indicator on the flip panel, which is convenient for measurement;

(4) A coaxiality detection device for different types of brake drums of the present utility model adopts a simple lever principle when measuring, and the positioning needle and the positioning needle sleeve are coordinated for positioning, and two radially arranged inner The hole positioning column assembly locates the brake drum, which can conveniently and quickly carry out online detection of the brake drum, and has high detection accuracy, simple operation, low cost, and is convenient for popularization and use.

Description of drawings

Fig. 1 is a schematic diagram of the front view of a coaxiality detection device for different types of brake drums of the present invention;

Fig. 2 is a top view structural schematic diagram of a coaxiality detection device for different types of brake drums of the present invention;

Fig. 3 is a structural schematic diagram of a cross-section in the D-D direction in Fig. 2;

Fig. 4 is a structural schematic diagram of the rolling support seat in the utility model.

Explanation of the labels in the schematic diagram: 1. Workbench; 2. Rolling support seat; 201. End surface rolling seat; 202. Steel ball; 203. Rolling base; 3. Positioning pin; 4. Inner hole positioning column; 5. Front positioning 6, positioning pin; 7, handle; 8, flap; 9, measuring rod assembly; 901, dial indicator; 902, dial indicator fixing clip; 903, adjusting guide rod; 904, adjusting pin; 905, 906, measuring rod pin; 907, table base; 908, measuring rod; 909, spring; 910, spring guide pin; 10, rotating baffle; 11, rear positioning plate.

Detailed ways

In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.

Example 1

With reference to Figure 1, Figure 2, Figure 3 and Figure 4, a coaxiality detection device for different types of brake drums in this embodiment mainly consists of a workbench 1, a rolling support seat 2, an inner hole positioning assembly, Turning plate 8 and measuring rod assembly 9 etc. are made up, and Fig. 1 is the structural schematic diagram that is placed with brake drum of this embodiment, and the center of workbench 1 is equipped with rolling support seat 2, makes braking when being used for testing. The drum can rotate freely, and a front positioning plate 5 and a rear positioning plate 11 are arranged in parallel on both sides of the workbench 1. The top of the rear positioning plate 11 is hinged to one end of the flap 8, and a rotating Baffle plate 10, the two sides of this rotating baffle plate 10 form a knuckle, one side of the knuckle is fixedly connected on the flap 8 by screws, and the apex of the knuckle is on the same plane as the outer surface of the rear positioning plate 11, which is used to limit the rotation of the flap 8. Rotational position; the other end of turnover plate 8 is equipped with positioning needle 6, and the upper end of described front positioning plate 5 is equipped with positioning needle sleeve, and turnover plate 8 and front positioning plate 5 pass through the cooperation between positioning pin 6 and positioning needle sleeve The positioning connection can quickly position the flap and avoid the shaking of the measuring rod assembly during detection. In order to facilitate the operation, a handle 7 is also installed on the end face of the turning plate 8 located at one end of the front positioning plate 5, which helps to improve the detection efficiency.

The measuring rod assembly 9 in this embodiment is installed on the turnover plate 8 (as shown in FIG. 3 ), and is used for detecting the brake drum to be detected. The measuring rod assembly 9 includes a dial indicator 901, a dial indicator fixing clip 902, an adjustment guide rod 903, a locking screw 905, a measuring rod pin 906, a table base 907 and a measuring rod 908, and a The measuring rod mounting hole on the end face of the vertical turnover plate 8, the gauge base 907 is installed in the measuring rod mounting hole, and the shoulder of the gauge base 907 is fixedly connected with the flap 8 by bolts, and the gauge base 907 is sleeved on the adjustment guide The outer circumference of the rod 903, and the table base 907 is slidingly connected with the adjustment guide rod 903, and the braking surface at different positions in the brake drum can be detected by adjusting the height of the adjustment guide rod 903. In addition, a threaded hole is provided on the upper side of the table base 907, and the locking screw 905 fixes the adjusting guide rod 903 through the threaded hole; a dial indicator fixing clip 902 is installed on the upper end of the adjusting guide rod 903, and the dial indicator 901 is installed on the adjustment guide rod 903 through the dial gauge fixing clip 902, and is used for displaying measurement changes. A through hole is provided inside the adjustment guide rod 903, and a measuring rod 908 is housed in the through hole, and a pin hole is provided in the middle part of the measuring rod 908, and the measuring rod pin 906 passes through the pin hole to make the measuring rod 908 and the adjusting guide rod 903 are hinged to form a lever structure. One end of the measuring rod 908 is in contact with the contact of the dial indicator 901, and the other end of the measuring rod 908 is arranged as an L-shaped extension of the lower end of the adjusting guide rod 903, and the head of the measuring rod 908 L-shaped end is provided with a spherical contact. The spherical contact is used for contacting with the braking surface of the brake drum to be detected, so as to increase the detection accuracy.

The above-mentioned adjusting guide rod 903 is also equipped with an adjusting pin 904 and a spring guide pin 910. The adjusting pin 904 is installed on the side opposite to the upper end of the adjusting guide rod 903 and the dial indicator 901, and is used to limit the rotation range of the measuring rod 908; The spring guide pin 910 is installed on the same side as the upper end of the adjustment guide rod 903 and the dial indicator 901, and the end of the spring guide pin 910 facing the measuring rod 908 is equipped with a spring 909. By adjusting the spring guide pin 910, the spring 909 can be changed to measure The pressure of the rod 908 ensures that the spherical contact is in full contact with the measuring surface, ensuring measurement accuracy.

The measuring rod assembly 9 is one of the key technologies of this embodiment, wherein the adjusting guide rod 903 is connected to the dial indicator 901 through the dial indicator fixing clip 902, and the measuring rod 908 can be wound around the measuring rod pin in the inner hole of the adjusting guide rod 903 The 906 turns create a lever that mirrors the jump change to the other side. The adjustment pin 904 limits the rotation range of the measuring rod 908, and the height of the measuring position is controlled by the locking screw rod 905, so that the measuring rod 908 detects the detection surface of the brake drum at a suitable position; the spring guide pin 910 on the adjusting guide rod 903 is compressed The spring 909 guarantees the necessary pressure of the measuring rod 908, ensures that the inspection value is accurate and reliable, and can accurately reflect the beating of the inner surface and inner hole of the brake drum on the dial indicator fixed on the flap 8, which is easy to observe.

The inner hole positioning assembly in this embodiment is installed on the workbench 1 for positioning the inner hole of the brake drum to be tested. The inner hole positioning assembly is composed of a positioning pin 3 and an inner hole positioning column 4, a bearing is installed at one end of the positioning pin 3, and the inner hole positioning column 4 is sleeved on the outer ring of the bearing; in order to install the inner hole positioning assembly On the workbench, a first positioning hole and a second positioning hole are opened on the workbench 1, and the first positioning hole and the second positioning hole are symmetrically distributed on the same diameter line of the rolling support seat 2, and the positioning pin 3 is installed in the first positioning hole and the second positioning hole, and the inner hole positioning column 4 on the same diameter line is used for positioning to prevent the brake drum from shaking, which ensures the positioning accuracy during detection. In addition, the positioning pin 3 is closely matched with the first positioning hole and the second positioning hole to ensure the accuracy and facilitate the disassembly of the inner hole positioning assembly. By replacing the inner hole positioning pin 4 with different outer diameter sizes, different models and sizes can be detected. Brake drums, enabling universal measurement of many types of brake drums.

The rolling support seat 2 in this embodiment includes an end surface rolling seat 201, a steel ball 202 and a rolling base 203 (as shown in Figure 4). The base 203 is fixed on the workbench 1, and the lower side of the end surface rolling seat 201 and the upper side of the rolling base 203 are provided with annular grooves, and steel balls 202 are housed in the annular grooves for making the end surface rolling seat 201 roll around the base The central axis of 203 rotates to meet the detection requirements.

In this embodiment, a brake drum is selected to detect and illustrate the detection method of coaxiality, and its steps are:

Step 1. Detection preparation: lift the handle 7 of the coaxiality detection device used for different types of brake drums, drive the positioning pin 6 to separate from the positioning needle sleeve, and at the same time make the flap 8 rotate around the hinge point, and pass the rotating baffle 10 limit rotation position;

Step 2. Brake drum positioning: place the brake drum to be detected on the rolling support seat 2, select the inner hole positioning assembly according to the inner diameter of the brake drum, and install the inner hole positioning assembly on the second One positioning hole and the second positioning hole, and the outer circular surfaces of the two inner hole positioning columns 4 are all in contact with the inner circular surface of the brake drum to form radial positioning;

Step 3. Position the measuring rod assembly 9: lift the handle 7, turn the flap 8 around the hinge point to a horizontal position, and ensure that the positioning pin 6 is closely matched with the positioning needle sleeve, so that the measuring rod assembly 9 is in the vertical direction and unable to shake;

Step 4. Adjust the measuring rod 908: first determine the position height of the brake drum to be measured, and lock the adjusted guide rod 903 with the adjusted height through the locking screw 905, and change the depth of the adjusting pin 904 and the spring guide pin 910 Limit the rotation range of the measuring rod 908 so that the contact of the measuring rod 908 is in close contact with the inner hole of the braking surface of the brake drum;

Step 5. Complete the inspection: Rotate the brake drum so that the brake drum rotates on the end surface rolling seat 201, observe the numerical change of the dial indicator 901, obtain the inspection result through data analysis, take out the brake drum, and proceed to the next round of inspection .

After a measurement is completed, the same type of brake drum can be directly put into the detection device of this embodiment for detection. In order to further improve the detection accuracy, the locking screw 905 can be used to detect multiple height positions. The detection of the position can reflect the quality of the workpiece as a whole.

Chinese patent application number: 201320001194.8 The name of the invention disclosed is a technical scheme of a brake drum full run-out inspection tool. The scheme uses the bearing on the tapered outer circle and the outer ring of the bearing in the wheel hub to coordinate positioning, and the lever dial indicator detection system The braking surface of the dynamic drum is beating, because the result of the positioning detection of the outer ring of the bearing in the hub is the coaxiality of the braking surface of the entire brake drum hub assembly after assembly, and the influencing factors are the cooperation between the outer ring of the bearing and the hub And the manufacturing accuracy of a single piece, the cooperation between the hub and the brake drum and the manufacturing accuracy of a single piece; the connecting rod of the dial indicator is connected by screw compression, and is in a suspended state. Measurement accuracy; in addition, the dial indicator measuring head of the device must be inserted into the brake drum to complete the detection, making the measured value difficult to observe. In the coaxiality detection device for different types of brake drums provided in this embodiment, one end of the measuring rod 908 in the measuring rod assembly 9 is in contact with the braking surface of the brake drum, and the other end is in contact with the dial indicator 901. By adopting the principle of lever structure, the detection data value of the coaxiality of the braking surface of the brake drum is displayed on the dial gauge 901. The structure is simple, the detection accuracy is high, and the universal measurement of various types of brake drums is realized, and the reading is convenient and the use cost is low. Low. Using the coaxiality detection method of this embodiment, the brake drum is placed in the detection device of this embodiment during measurement. Since the positioning and contact parts of the brake drum adopt the bearing box rolling support structure, it only needs to be easily rotated manually during detection. For the moving drum, the coaxiality of the brake drum inner hole can be accurately and conveniently measured through the measuring rod assembly 9 on the turnover plate 8, and the adjustment pin 904 does not need to be repeatedly calibrated when testing the same type of brake drum. The method can conveniently and quickly carry out on-line detection of the brake drum, and has high detection precision, simple operation, low cost, and is convenient for popularization and use.

The above schematically describes the utility model and its implementation, which is not restrictive, and what is shown in the accompanying drawings is only one implementation of the utility model, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, and without departing from the purpose of the invention of the utility model, without creatively designing a structural mode and an embodiment similar to the technical solution, it shall belong to the utility model. protected range.

Claims (6)

1. A coaxiality detection device for different types of brake drums, comprising a workbench (1), characterized in that: it also includes a rolling support seat (2), an inner hole positioning assembly, a flap (8) and The measuring rod assembly (9), the center of the workbench (1) is equipped with a rolling support seat (2), and the front positioning plate (5) and the rear positioning plate are arranged in parallel on both sides of the workbench (1) (11), the top of the rear positioning plate (11) is hinged with one end of the turnover plate (8), and the other end of the turnover plate (8) is equipped with a positioning pin (6), and the described front positioning plate (5) The upper end of the upper end is equipped with a positioning needle sleeve, and the flap (8) and the front positioning plate (5) are positioned and connected by cooperation between the positioning pin (6) and the positioning needle sleeve; The measuring rod assembly (9) is installed on the flap (8) for detecting the brake drum to be detected; The inner hole positioning assembly is installed on the workbench (1) and is used for positioning the inner hole of the brake drum to be tested. 2. A coaxiality detection device for different types of brake drums according to claim 1, characterized in that: the measuring rod assembly (9) includes a dial indicator (901), a dial indicator Fixing clip (902), adjusting guide rod (903), locking screw rod (905), measuring rod pin (906), table base (907) and measuring rod (908), wherein: a There is a measuring rod mounting hole on the end face of the vertical flap (8), and a meter base (907) is installed in the measuring rod mounting hole, and the shoulder of the meter base (907) is fixedly connected with the flap (8) by bolts, so The above table base (907) is set on the outer circumference of the adjustment guide rod (903), and the table base (907) is slidingly connected with the adjustment guide rod (903), and a threaded hole is opened on the upper side of the table base (907), and the locking screw ( 905) fix the adjusting guide rod (903) through the threaded hole; the upper end of the adjusting guide rod (903) is equipped with a dial gauge fixing clip (902), and the dial gauge (901) passes through the dial gauge The fixing clip (902) is installed on the adjustment guide rod (903); a through hole is provided inside the adjustment guide rod (903), and a measuring rod (908) is housed in the through hole, and a There is a pin hole, and the measuring rod pin (906) passes through the pin hole so that the measuring rod (908) is hinged with the adjusting guide rod (903), and one end of the measuring rod (908) is connected to the contact of the dial indicator (901) In contact with each other, the other end of the measuring rod (908) is set to an L-shaped extension of the lower end of the adjusting guide rod (903), and a spherical contact is provided at the head of the L-shaped end of the measuring rod (908), which is used for Contact with the braking surface of the brake drum to be tested. 3. A coaxiality detection device for different types of brake drums according to claim 1, characterized in that: the inner hole positioning assembly includes a positioning pin (3) and an inner hole positioning column ( 4), wherein: a bearing is installed at one end of the positioning pin (3), and the positioning pin (4) in the inner hole is set on the outer ring of the bearing; a first positioning hole and a second positioning hole are provided on the workbench (1). Positioning holes, the first positioning hole and the second positioning hole are symmetrically distributed on the same diameter line of the rolling support seat (2), and the positioning pin (3) is installed in the first positioning hole and the second positioning hole , and the positioning pin (3) is clearance-fitted with the first positioning hole and the second positioning hole to form a detachable inner hole positioning assembly. 4. A coaxiality detection device for different types of brake drums according to claim 2 or 3, characterized in that: the adjustment guide rod (903) is also equipped with adjustment pins (904) and The spring guide pin (910), the adjustment pin (904) is installed on the side opposite to the dial indicator (901) at the upper end of the adjustment guide rod (903), and the spring guide pin (910) is installed on the adjusting The upper end of the guide rod (903) is on the same side as the dial indicator (901), and the end of the spring guide pin (910) facing the measuring rod (908) is equipped with a spring (909), which can be changed by adjusting the spring guide pin (910). The pressure of the spring (909) against the measuring rod (908). 5. A coaxiality detection device for different types of brake drums according to claim 4, characterized in that: said flap (8) is provided with a handle on the end face of one end of the front positioning plate (5) (7); the upper surface of the flap (8) and the hinged end of the rear positioning plate (11) is equipped with a rotary baffle (10), and a knuckle is formed on both sides of the swivel baffle (10), and one side of the knuckle is fixedly connected by screws On the turnover plate (8), and the corner apex and the outer surface of the rear positioning plate (11) are located on the same plane. 6. A coaxiality detection device for different types of brake drums according to claim 5, characterized in that: the rolling support seat (2) includes an end surface rolling seat (201), a steel ball (202 ) and a rolling base (203), the rolling base (203) is located at the center of the upper surface of the workbench (1), and the rolling base (203) is fixed on the workbench (1) by bolts, the described The lower side of the end surface rolling seat (201) and the upper side of the rolling base (203) are provided with annular grooves, and steel balls (202) are housed in the annular grooves for making the end surface rolling seat (201) rotate around the rolling base ( 203) the central axis rotates.