A camshaft involute detection device

Abstract

The application discloses a brake camshaft involute detection device and belongs to the technical field of vehicle part detection devices. The technical scheme is characterized in that the device comprises an operating frame, a detection beam arranged on the operating frame, a positioning assembly for clamping and positioning the shaft body of the brake camshaft, and a driving assembly. A micrometer gauge for detecting the involute of the end cam is arranged on the detection beam. When the brake camshaft to be detected is located at a set position, the contact of the micrometer gauge abuts against the involute curved surface of the brake camshaft to be detected. The driving assembly is used for driving the contact of the micrometer gauge to move along the involute track of the standard cam. The contact of the micrometer gauge is driven by the driving assembly to move along the involute track of the standard cam, so that whether the brake camshaft is qualified can be judged according to the swing amplitude of the pointer of the micrometer gauge, and the operation is convenient and fast.

Description

Technical Field

[0001] This invention relates to the field of vehicle component testing equipment, and in particular to a brake camshaft involute detection device. Background Technology

[0002] The brake camshaft is a common component in vehicle braking systems, primarily used for braking. The structure of the brake camshaft can be found in [reference needed]. Figure 1 The brake camshaft 1 includes a shaft 11 and an end cam 12 located at the end of the shaft 11. The boundary surface of the end cam 12 is an involute surface 121. During the production and processing of the brake camshaft 1, whether the involute of the end cam 121 is standard directly affects the braking quality of the vehicle.

[0003] Currently, the involute curve of the brake camshaft is generally inspected using a coordinate measuring machine (CMM). When using a CMM to inspect the involute curve of the brake camshaft, a corresponding positioning fixture needs to be designed to position the brake camshaft on the CMM's worktable. Using a CMM to inspect the involute curve of the brake camshaft requires a high level of knowledge and experience from the operator; ordinary workers cannot use a CMM to inspect the involute curve of the brake camshaft. Summary of the Invention

[0004] The purpose of this invention is to provide a brake camshaft involute detection device that is easy to use and convenient to operate.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a brake camshaft involute detection device, comprising an operating frame, a detection beam disposed on the operating frame, a positioning component for clamping and positioning the shaft of the brake camshaft, and a drive component; the detection beam is provided with a dial indicator for detecting the involute of the end cam, and when the brake camshaft to be tested is in the set position, the contact of the dial indicator abuts against the involute curved surface of the brake camshaft to be tested; the drive component is used to drive the contact of the dial indicator to move along the involute trajectory of a standard cam.

[0006] By adopting the above scheme, the dial indicator's contacts are driven by the drive component to move along the involute trajectory of a standard cam. By observing the dial indicator's pointer, the oscillation amplitude of the pointer is used to detect and judge whether the involute of the brake camshaft is qualified. The operation is simple and convenient.

[0007] Preferably, the drive assembly includes a mounting box mounted on an operating frame, wherein a drive gear and a driven gear meshing with each other are disposed within the mounting box; the drive gear is rotatably connected to the mounting box, and the driven gear is fixedly connected to the mounting box; the mounting box is rotatably connected to the operating frame about the axis of the driven gear; standard cylinders coaxially arranged with the driven gear are fixed to both sides of the driven gear, and the diameter of the standard cylinders is equal to the diameter of the involute base circle of the standard cam; positioning cylinders coaxially arranged with the drive gear are fixed to both sides of the drive gear; the detection beam passes longitudinally through the mounting box, and the upper and lower surfaces of the detection beam abut against the circumferences of the standard cylinders and the positioning cylinders, respectively; the axial direction of the dial indicator's contact is arranged along the axial direction of the detection beam, and the axis of the dial indicator's contact is located in the plane containing the upper surface of the detection beam.

[0008] By adopting the above scheme, the drive gear is rotated, and under the force of the drive gear on the driven gear, the mounting box rotates around the axis of the driven gear. Under the pressure of the positioning cylinder on the detection beam, the detection beam rolls around the circumference of the standard cylinder, so that the dial indicator contact moves along the involute trajectory of the standard cam, thereby detecting the involute surface of the brake camshaft under test. The operation is simple and easy to use.

[0009] Preferably, the driving gear meshes with an operating gear, the operating gear is rotatably connected to the mounting box about its axis, and the operating gear is fixed with a knob coaxially arranged therewith.

[0010] By adopting the above scheme, and by setting the gears and knobs, the drive gear is driven by rotating the knobs, making operation convenient.

[0011] Preferably, the positioning assembly includes a connecting rod vertically mounted on the operating frame and a positioning sleeve fixed to the lower end of the connecting rod; the positioning sleeve is coaxially mounted with a standard cylinder and is used to insert into the shaft of the brake camshaft to be tested.

[0012] By adopting the above scheme and setting a positioning bushing, the shaft of the detected brake camshaft can be easily and quickly radially positioned by inserting the shaft body of the positioning bushing into the positioning bushing.

[0013] Preferably, at least three mounting holes are respectively provided on the circumferential surfaces of both ends of the positioning bushing, which are axially arranged radially along the positioning bushing. The mounting holes are blind holes, and a positioning hole coaxially arranged with the mounting hole is provided at the bottom of the mounting hole. The positioning hole penetrates the circumferential wall of the positioning bushing. A positioning ball is provided in the mounting hole for abutting against the circumferential surface of the shaft. The spherical surface of the positioning ball protrudes from the inner and outer circumferential surfaces of the positioning bushing. Positioning nuts are respectively provided at both ends of the positioning bushing for threaded engagement with the positioning bushing. A positioning cone surface is provided on the inner axial surface of the positioning nut near the positioning bushing for abutting against the positioning ball.

[0014] By adopting the above scheme, the positioning nuts at both ends of the positioning sleeve are screwed into the positioning sleeve, and then the force of the positioning cone surface on the positioning ball is used to perform multi-point positioning on the circumferential surface of the brake camshaft through the positioning cylinder, thereby fixing the shaft body and the positioning sleeve relatively. The operation is convenient and quick, and the radial force is applied at multiple points simultaneously, resulting in high radial positioning accuracy.

[0015] Preferably, the positioning nut includes a left-handed nut and a right-handed nut, which are located at both ends of the positioning bushing and are threadedly engaged with the positioning bushing.

[0016] By adopting the above scheme, the positioning nuts at both ends of the positioning bushing are left-handed and right-handed nuts with opposite directions of rotation, which can effectively prevent the positioning nuts at both ends of the positioning bushing from loosening at the same time, thereby firmly and effectively positioning and fixing the brake camshaft shaft.

[0017] Preferably, the detection beam includes two parallel detection arms, and each end of the two detection arms is provided with a connecting block fixedly connected to the detection arms; a slide rail is provided on the side surface of the detection arms that is close to each other, which slopes downward from the end away from the dial indicator to the end of the dial indicator; a slider is provided in the slide rail and is slidably connected to it along the length of the slide rail, and the dial indicator is fixedly connected to the slider.

[0018] By adopting the above scheme, the position of the dial indicator can be finely adjusted by sliding the dial indicator along the length of the slide, thus facilitating the correction of the dial indicator's contact position and making the detection of involute surfaces more accurate.

[0019] Preferably, the end of the detection beam is provided with an adjusting screw that is arranged along the length of the slide rail. The adjusting screw is rotatably connected to the connecting block around its axis, and the adjusting screw is threadedly engaged with the slider.

[0020] By adopting the above scheme, and by adjusting the setting of the screw, the position of the slider on the slide can be conveniently and quickly adjusted and positioned by rotating the adjusting screw.

[0021] Preferably, the upper and lower ends of the connecting rod are respectively fixed with an upper connecting stud and a lower connecting stud arranged coaxially with the connecting rod; the circumferential surface of the positioning bushing is provided with a threaded connecting hole arranged radially along the positioning bushing, and the lower connecting stud is threadedly engaged with the threaded connecting hole; the lower surface of the operating frame is provided with an axially penetrating assembly hole, the upper connecting stud axially passes through the assembly hole, and a fixing nut that is threadedly engaged with the upper connecting stud is provided at the upper part of the mounting hole.

[0022] By adopting the above scheme, the positioning sleeve is installed onto the connecting rod through the threaded engagement of the lower connecting stud and the threaded connecting hole. Then, the connecting rod is installed on the operating frame through the cooperation of the upper connecting stud and the fixing nut at the upper end of the connecting rod. This allows for convenient and quick installation and removal of the positioning sleeve.

[0023] Preferably, a positioning buckle is fixed on the upper circumferential surface of the connecting rod. When the positioning sleeve is coaxially arranged with the standard cylinder, the positioning buckle abuts against the side of the operating frame. An elastic pressure plate for pressing and positioning the positioning buckle is provided on the side of the operating frame.

[0024] By adopting the above scheme, when the brake camshaft to be tested needs to be replaced, the brake camshaft can be easily installed by rotating the connecting rod. After the brake camshaft to be tested is installed, the connecting rod is rotated until the positioning buckle abuts against the side of the operating frame. Then, the positioning buckle is pressed and positioned by the elastic pressure plate, thereby preventing the brake camshaft from rotating around the axis of the connecting rod when the brake camshaft is tested. Through the combined design of the positioning buckle and the elastic pressure plate, the installed camshaft to be tested can be quickly adjusted to the testing position, making the operation convenient.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. By rotating the operating gear, the entire mounting box rotates around the axis of the driven gear under the force of the driving gear on the driven gear. Under the action of the standard cylinder and the positioning cylinder, the contact point between the upper surface of the detection beam and the standard cylinder changes continuously around the center of the standard cylinder, thereby causing the dial indicator's contact to move along the involute trajectory of the standard cam. The operation is simple and easy to use.

[0027] 2. By screwing the positioning nuts at both ends of the positioning bushing into the positioning bushing, the force exerted by the positioning cone on the positioning ball is used to perform multi-point positioning on the circumferential surface of the brake camshaft through the positioning cylinder, thereby fixing the shaft body and the positioning bushing relative to each other. The operation is convenient and quick, and the radial force is applied at multiple points simultaneously, resulting in high radial positioning accuracy.

[0028] 3. The upper end of the connecting rod is mounted on the operating frame through the cooperation of the upper connecting stud and the fixing nut. When the brake camshaft under test is replaced, the connecting rod can be rotated, making the replacement operation more convenient. Through the combined setting of positioning buckle and elastic pressure plate, the installed camshaft under test can be quickly adjusted to the testing position, making the operation convenient. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the brake camshaft in the background art.

[0030] Figure 2 This is a schematic diagram of the involute detection device for brake camshafts.

[0031] Figure 3 This is a schematic diagram illustrating the structure of the driving component.

[0032] Figure 4 This is a structural diagram of the positioning component.

[0033] Figure 5 This is a structural diagram illustrating the positioning bushing.

[0034] Figure 6 This is a structural diagram illustrating the connecting rod.

[0035] Figure 7 This is a structural diagram illustrating the assembly relationship between the connecting rod and the operating frame.

[0036] Figure 8 This is a structural diagram of the positioning buckle.

[0037] Figure 9 This is a schematic diagram of the structure of the testing beam.

[0038] Figure 10 This is a schematic diagram of the adjusting screw installation structure.

[0039] In the diagram, 1. Brake camshaft; 11. Shaft body; 12. End cam; 121. Involute surface; 2. Operating frame; 21. Assembly hole; 3. Inspection beam; 31. Inspection arm; 311. Slide rail; 32. Connecting block; 33. Slider; 34. Adjusting screw; 4. Positioning assembly; 41. Positioning bushing; 411. Mounting hole; 412. Positioning hole; 413. Threaded connection hole; 42. Positioning ball; 43. Positioning nut; 44. 1. Positioning cone surface; 5. Drive assembly; 51. Mounting box; 52. Drive gear; 521. Positioning cylinder; 53. Driven gear; 531. Standard cylinder; 54. Operating gear; 6. Dial indicator; 7. Connecting rod; 711. Upper connecting stud; 712. Lower connecting stud; 713. Fixing nut; 8. Positioning buckle; 81. Base plate; 82. Baffle; 83. Buckle hole; 84. Locking threaded hole; 9. Elastic pressure plate. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0041] Example:

[0042] A brake camshaft involute detection device, with reference to Figure 2 and Figure 3 The device includes an operating frame 2, a detection beam 3 mounted on the operating frame 2, a positioning assembly 4 for clamping and positioning the shaft 11 of the brake camshaft 1, and a drive assembly 5. A dial indicator 6 for detecting the involute curve of the camshaft 12 is fixed on the detection beam 3. When the brake camshaft 1 under test is in the set position, the contact of the dial indicator 6 abuts against the involute curved surface 121 of the camshaft 12 under test. The drive assembly 5 drives the contact of the dial indicator 6 to move along the involute trajectory of the standard camshaft 12. The operating frame 2 serves as a base for mounting various components, facilitating the operator's gripping and operation of the brake camshaft involute detection device.

[0043] Reference Figure 2 and Figure 3The drive assembly 5 includes a mounting box 51, within which a drive gear 52 and a driven gear 53 mesh with each other. The drive gear 52 is rotatably connected to the mounting box 51, and the driven gear 53 is fixedly connected to the mounting box 51. The mounting box 51 is rotatably connected to the operating frame 2 about the axis of the driven gear 53. The drive gear 52 meshes with an operating gear 54, which is rotatably connected to the mounting box 51 about its axis. A knob coaxially mounted on the operating gear 54 is fixed to the operating gear 54. Standard cylinders 531, coaxially mounted with the driven gear 53, are fixed to the two side surfaces of the driven gear 53. The diameter of the standard cylinders 531 is equal to the diameter of the involute base circle of the standard cam 12. Positioning cylinders 521, coaxially mounted with the drive gear 52, are fixed to the two side surfaces of the drive gear 52.

[0044] Reference Figure 2 and Figure 3 The detection beam 3 passes longitudinally through the mounting box 51, and its upper and lower surfaces abut against the circumferences of the standard cylinder 531 and the positioning cylinder 521, respectively. A dial indicator 6 is positioned at one end of the detection beam 3, with the axis of its contact point aligned with the axis of the detection beam 3, and the axis of the contact point located on the plane containing the upper surface of the detection beam 3. When the operating gear 54 is rotated, under the force of the driving gear 52 on the driven gear 53, the mounting box 51 rotates around the axis of the driven gear 53. Furthermore, under the pressure of the positioning cylinder 521 on the detection beam 3, the detection beam 3 rolls around the circumference of the standard cylinder 531, causing the contact point of the dial indicator 6 to move along the involute trajectory of a standard cam.

[0045] Reference Figure 2 , Figure 4 and Figure 5The positioning component 4 includes a connecting rod 7 vertically mounted on the operating frame 2 and a positioning sleeve 41 fixed to the lower end of the connecting rod 7; the positioning sleeve 41 is coaxially mounted with the standard cylinder 531. The positioning sleeve 41 is used to insert into the shaft 11 of the brake camshaft 1 to be tested. At least three mounting holes 411 are respectively opened on the circumferential surfaces of both ends of the positioning sleeve 41, which are axially arranged radially along the positioning sleeve 41. In this embodiment, three (but not limited to three) mounting holes 411 are respectively opened on the circumferential surfaces of both ends of the positioning sleeve 41, which are evenly distributed around the axis of the positioning sleeve 41. The mounting holes 411 are blind holes, and a positioning hole 412 is opened at the bottom of the mounting hole 411, which is coaxially mounted with the mounting hole 411 and penetrates the circumferential wall of the positioning sleeve 41. A positioning ball 42 is provided in the mounting hole 411 for abutting against the circumferential surface of the shaft 11, and the spherical surface of the positioning ball 42 protrudes from the inner and outer circumferential surfaces of the positioning sleeve 41. The positioning sleeve 41 has positioning nuts 43 at both ends that are threadedly engaged with it. The inner shaft surface of the positioning nut 43 near the positioning sleeve 41 has a positioning conical surface 431 for abutting against the positioning ball 42. The positioning nuts 43 at both ends of the positioning sleeve 41 are left-handed and right-handed nuts with opposite rotation. When inspecting the brake camshaft 1, the shaft 11 of the brake camshaft 1 is inserted into the mounting hole 411, adjusted to a suitable position, and then the positioning nuts 43 at both ends are screwed on. The positioning conical surface 431 of the positioning nuts 43 applies pressure to the positioning ball 42, thereby using multiple positioning balls 42 to position the shaft 11 at multiple points, fixing the shaft 11 relative to the positioning sleeve 41, effectively preventing axial movement of the shaft 11 within the positioning sleeve 41 during inspection. The two positioning nuts 43 are left-handed and right-handed nuts with opposite directions of rotation, which can effectively prevent the positioning nuts 43 at both ends of the positioning bushing 41 from loosening simultaneously under the action of external torque.

[0046] Reference Figure 5 , Figure 6 and Figure 7 The upper and lower ends of the connecting rod 7 are respectively fixed with an upper connecting stud 711 and a lower connecting stud 712, which are coaxially arranged with the connecting rod 7. An assembly hole 21 is provided on the lower surface of the operating frame 2. The upper connecting stud 711 passes axially through the assembly hole 21, and a fixing nut 713 is provided at the upper part of the assembly hole 21, threadedly engaging with the upper connecting stud 711. A threaded connection hole 413 is provided on the circumferential surface of the positioning sleeve 41, radially arranged along the positioning sleeve 41. The lower connecting stud 712 is threadedly engaged with the threaded connection hole 413. By screwing the lower connecting stud 712 into the threaded connection hole 413, the positioning sleeve 43 is fixed to the lower end of the connecting rod 7. Then, through the cooperation of the upper connecting stud 711 and the fixing nut 713, the connecting rod 7 is installed on the operating frame 2.

[0047] Reference Figure 7 and Figure 8 A positioning buckle 8 is fixed to the upper circumferential surface of the connecting rod 7. The positioning buckle 8 includes a base plate 81 and a baffle 82 fixed to one side of the base plate 81. When the positioning bushing 41 is coaxially arranged with the standard cylinder 531, the baffle 82 of the positioning buckle 8 abuts against the side of the operating frame 2. The base plate 81 has a buckle hole 83 for engaging with the connecting rod 7. A locking threaded hole 84 communicating with the buckle hole 83 is provided on one side of the base plate 81. By inserting a screw that engages with the locking threaded hole 84 into the locking threaded hole 84, the positioning buckle 8 is fixed to the connecting rod 7. An elastic pressure plate 9 is provided on the side of the operating frame 2 for pressing and positioning the positioning buckle 8. The elastic pressure plate 9 is made of a thin metal sheet with elasticity, and one end of the elastic pressure plate 9 is pressed and fixed to the operating frame 2 by a screw. When it is necessary to replace the brake camshaft 1 under test, loosen the screw at the elastic pressure plate 9, rotate or remove the elastic pressure plate 9, and then rotate the connecting rod 7 to facilitate the replacement of the brake camshaft 1. After the brake camshaft 1 under test is installed, rotate the connecting rod 7 until the stop plate of the positioning buckle 8 abuts against the side of the operating frame 2; then reset the elastic pressure plate 9, and use the elastic pressure plate 9 to press and position the positioning buckle 8, thereby preventing the brake camshaft 1 from rotating around the axis of the connecting rod 7 when testing the brake camshaft 1. Through the combined setting of the positioning buckle 8 and the elastic pressure plate 9, the installed camshaft 12 under test can be quickly adjusted to the testing position, making the operation convenient.

[0048] Reference Figure 2 , Figure 9 as well as Figure 10 The detection beam 3 includes two parallel detection arms 31, located on either side of the driven gear 53. Connecting blocks 32 are fixedly connected to each detection arm 31 at both ends. The connecting blocks 32 are screwed to the two detection arms 31, connecting them into a single unit. A slide rail 311, sloping downwards from the end away from the dial indicator 6, is formed on the surface of the detection arms 31 on the side closest to each other. A slider 33, slidably connected to the slide rail 311 along its length, is fixedly connected to the dial indicator 6. In this embodiment, the angle of intersection between the slide rail 311 and the lower surface of the detection beam 3 is 9 degrees 2 minutes. The end of the detection beam 3 is provided with an adjusting screw 34 that is arranged along the length of the slide rail 311. The adjusting screw 34 is rotatably connected to the connecting block 32 around its axis. The adjusting screw 34 is threadedly engaged with the slider 33. By rotating the adjusting screw 34, the position of the dial indicator 6 contact can be finely adjusted.

[0049] The specific implementation principle of this embodiment is as follows:

[0050] Loosen the positioning nuts 43 at both ends of the positioning sleeve 41, and insert the shaft 11 of the brake camshaft 1 into the positioning sleeve 41. Tighten the positioning nuts 43 to fix the shaft 11 and the positioning sleeve 43 relative to each other. Rotate the connecting rod, and use the positioning buckle 8 and the elastic pressure plate 9 to circumferentially position the connecting rod, so that the positioning sleeve 41 rotates to a position coaxial with the standard cylinder 531. Slide the micrometer 6 along the length of the slide 31 to finely adjust the position of the micrometer 6 contact, so that the micrometer 6 contact is on the plane of the upper surface of the detection beam 3. Under the force of the drive gear 52 on the driven gear 53, the mounting box 51 rotates around the axis of the driven gear 53, and under the pressure of the positioning cylinder 521 on the detection beam 3, the detection beam 3 rolls around the circumference of the standard cylinder 531, so that the micrometer 6 contact moves along the involute trajectory of the standard cam. The inspectors observed the swing range of the pointer on the dial indicator 6 to determine whether the involute curve of the brake camshaft 1 was up to standard.

[0051] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A device for detecting the involute curve of a brake camshaft, characterized in that: The system includes an operating frame (2), a detection beam (3) mounted on the operating frame (2), a positioning component (4) for clamping and positioning the shaft (11) of the brake camshaft (1), and a drive component (5). The detection beam (3) is equipped with a dial indicator (6) for detecting the involute curve of the end cam (12). When the brake camshaft (1) to be tested is in the set position, the contact of the dial indicator (6) abuts against the involute curved surface (121) of the brake camshaft (1) to be tested. The drive component (5) is used to drive the contact of the dial indicator (6) to move along the involute trajectory of a standard cam. The drive component (5) includes a mounting box (51) mounted on the operating frame (2). The mounting box (51) contains a meshing drive gear (52) and a driven gear (53). The drive gear (52) is rotatably connected to the mounting box (51), and the driven gear... The gear (53) is fixedly connected to the mounting box (51); the mounting box (51) is rotatably connected to the operating frame (2) around the axis of the driven gear (53); the driven gear (53) has a standard cylinder (531) coaxially arranged with the driven gear (53) fixed on both sides of its side surface, and the diameter of the standard cylinder (531) is equal to the diameter of the involute base circle of the standard cam; the driving gear (52) has a positioning cylinder (521) coaxially arranged with the driving gear (52) fixed on both sides of its side surface; the detection beam (3) passes longitudinally through the mounting box (51), and the upper and lower surfaces of the detection beam (3) abut against the circumference of the standard cylinder (531) and the positioning cylinder (521) respectively; the axial direction of the contact of the dial indicator (6) is arranged along the axial direction of the detection beam (3), and the axis of the contact of the dial indicator (6) is located in the plane of the upper surface of the detection beam (3).

2. The brake camshaft involute detection device according to claim 1, characterized in that: The drive gear (52) meshes with the operating gear (54), which is rotatably connected to the mounting box (51) around its axis. The operating gear (54) is fixed with a knob coaxially arranged therewith.

3. The brake camshaft involute detection device according to claim 1, characterized in that: The positioning component (4) includes a connecting rod (7) vertically mounted on the operating frame (2) and a positioning bushing (41) fixed to the lower end of the connecting rod (7); the positioning bushing (41) is coaxially mounted with the standard cylinder (531) and is used to insert into the shaft (11) of the brake camshaft (1) to be tested.

4. The brake camshaft involute detection device according to claim 3, characterized in that: At least three mounting holes (411) are respectively provided on the circumferential surfaces of both ends of the positioning bushing (41) and are arranged radially along the positioning bushing (41). The mounting holes (411) are blind holes. The bottom of the mounting holes (411) is provided with positioning holes (412) arranged coaxially with the mounting holes (411). The positioning holes (412) penetrate the circumferential wall of the positioning bushing (41). A positioning ball (42) for abutting against the circumferential surface of the shaft body (11) is provided in the mounting hole (411). The spherical surface of the positioning ball (42) protrudes from the inner and outer circumferential surfaces of the positioning bushing (41). A positioning nut (43) is provided at both ends of the positioning bushing (41) and is threadedly engaged with the positioning bushing (41). The inner axial surface of the positioning nut (43) near the positioning bushing (41) is provided with a positioning cone surface (431) for abutting against the positioning ball (42).

5. The brake camshaft involute detection device according to claim 4, characterized in that: The positioning nut (43) includes a left-handed nut and a right-handed nut, which are located at both ends of the positioning bushing (41) and are threadedly engaged with the positioning bushing (41).

6. The brake camshaft involute detection device according to claim 1, characterized in that: The detection beam (3) includes two parallel detection arms (31), and each end of the two detection arms (31) is provided with a connecting block (32) fixedly connected to the detection arm (31); a slide (311) is provided on the side surface of the detection arms (31) that is close to each other, which is inclined downward from the end away from the dial indicator (6) to the end of the dial indicator (6); a slider (33) is provided in the slide (311) and is slidably connected to it along the length of the slide (311), and the dial indicator (6) is fixedly connected to the slider (33).

7. The brake camshaft involute detection device according to claim 6, characterized in that: The end of the detection beam (3) is provided with an adjusting screw (34) whose length direction is along the length direction of the slide (311). The adjusting screw (34) is rotatably connected to the connecting block (32) around its axis. The adjusting screw (34) is threadedly engaged with the slider (33).

8. The brake camshaft involute detection device according to claim 3, characterized in that: The upper and lower ends of the connecting rod (7) are respectively fixed with an upper connecting stud (711) and a lower connecting stud (712) coaxially arranged with the connecting rod (7); the circumferential surface of the positioning bushing (41) is provided with a threaded connecting hole (413) arranged radially along the positioning bushing (41), and the lower connecting stud (712) is threadedly engaged with the threaded connecting hole (413); the lower surface of the operating frame (2) is provided with an axially penetrating assembly hole (21), the upper connecting stud (711) axially passes through the assembly hole (21), and the upper part of the assembly hole (21) is provided with a fixing nut (713) threadedly engaged with the upper connecting stud (711).

9. The brake camshaft involute detection device according to claim 8, characterized in that: The upper circumferential surface of the connecting rod is fixed with a positioning buckle (8). When the positioning bushing (41) is coaxially set with the standard cylinder (531), the positioning buckle (8) abuts against the side of the operating frame (2). The side of the operating frame (2) is provided with an elastic pressure plate (9) for pressing and positioning the positioning buckle (8).

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