Exhaust pipe size detection device

Abstract

The utility model relates to the technical field of exhaust pipe size detection, in particular to an exhaust pipe size detection device, which comprises a detection workbench; the two groups of exhaust pipe fixing plates are arranged above the detection workbench and are used for supporting the exhaust pipe; the limiting device is arranged in the detection workbench, and the limiting device comprises two sets of shells which are symmetrically arranged at the two ends of the exhaust pipe and used for limiting the exhaust pipe in the middle position; and each group of inner diameter detection device is arranged at the lower part in the shell and is used for detecting the inner diameter of the exhaust pipe. By operating the limiting device, a part of the structure of the inner diameter detection device can be inserted into the exhaust pipe by the limiting device, and at the moment, the inner diameter detection device is operated, so that no gap between the inner diameter detection device and the exhaust pipe can be ensured, and the inner wall of the exhaust pipe cannot be scratched.

Description

Technical Field

[0001] The utility model relates to the technical field of exhaust pipe size detection, in particular to an exhaust pipe size detection device. Background Art

[0002] The exhaust pipe is a part of the engine exhaust system. The exhaust system mainly includes the exhaust manifold, exhaust pipe and muffler. After the exhaust pipe is produced, it needs to be dimensionally inspected to ensure that it is qualified. During the inspection, an exhaust pipe dimension detection device is needed.

[0003] However, when the existing exhaust pipe size detection device is used, the exhaust pipe is fixed and the inner diameter and outer diameter of the exhaust pipe are measured by using a measuring device. During the inner diameter measurement process, a knife-shaped measuring claw is mostly inserted into the exhaust pipe and moved outward. The measuring claw stops after contacting the inner wall of the exhaust pipe and a reading is taken. However, in order to make the measuring claw completely contact with the inner wall of the exhaust pipe, the thickness of the measuring claw itself needs to be minimized, which makes the measuring claw sharper. During measurement, the position of the measuring claw needs to be adjusted multiple times so that the measuring claw and the center of the exhaust pipe are in the same plane. During the adjustment process, the measuring claw will contact the inner wall of the exhaust pipe multiple times, which can easily cause scratches on the inner wall of the exhaust pipe. Utility Model Content

[0004] The utility model aims to solve the problem that in the existing exhaust pipe size detection device, the position of the measuring claw needs to be adjusted multiple times during measurement, resulting in the measuring claw contacting the inner wall of the exhaust pipe multiple times, causing scratches on the inner wall of the exhaust pipe.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] An exhaust pipe size detection device, comprising:

[0007] Inspection workbench;

[0008] Two sets of exhaust pipe fixing plates are both arranged above the detection workbench to support the exhaust pipe;

[0009] A limit device is arranged inside the detection workbench, and the limit device comprises: two sets of shells, symmetrically arranged at both ends of the exhaust pipe, and used to limit the exhaust pipe to a middle position;

[0010] Two sets of inner diameter detection devices, each set of inner diameter detection devices is arranged at the lower part of the inner part of the shell, and is used to detect the inner diameter of the exhaust pipe;

[0011] Two groups of outer diameter detection devices, each group of outer diameter detection devices is arranged above the interior of the shell, and is used to detect the outer diameter of the exhaust pipe.

[0012] Preferably, each group of the inner diameter detection devices comprises:

[0013] A transmission assembly, consisting of a belt and two sets of pulleys, wherein the belt is arranged on the edges of the two sets of pulleys;

[0014] a rotating disc, coaxially arranged with a set of said pulleys;

[0015] Two groups of rotating blocks, the center of each group of rotating blocks is fixedly connected to the axis of the pulley; a through hole is opened inside the rotating block;

[0016] Two groups of rotating rods, each group of rotating rods is arranged in the through hole and is slidably connected with the rotating block through the through hole; a baffle is arranged on the surface of the rotating rod, a spring is arranged between the baffle and the rotating block, and the fitting is sleeved on the rotating rod; a cylindrical pin is arranged at one end of the rotating rod away from the rotating block;

[0017] Two sets of inner diameter measuring plates, each set of inner diameter measuring plates consists of a first vertical rod and a first cross rod, the bottom end of the first vertical rod is fixedly connected to one end of the first cross rod; a sliding groove is provided on the surface of the first vertical rod, and is slidably connected to the cylindrical pin through the sliding groove;

[0018] An inner diameter scale, the surface of which is in contact with the first crossbar;

[0019] Two groups of inner diameter limiting rods, each group of inner diameter limiting rods is arranged at the top end of the first vertical rod and is rotatably connected to the first vertical rod.

[0020] Preferably, one end of the first cross bar away from the first vertical bar and an edge of the inner diameter limiting rod close to the exhaust pipe are on the same vertical line.

[0021] Preferably, a semicircular notch is provided at the top of the exhaust pipe fixing plate.

[0022] Preferably, each group of the outer diameter detection devices comprises:

[0023] A double-ended threaded rod, which passes through a corresponding position of the housing and is rotatably connected to the housing;

[0024] A hand wheel fixedly connected to one end of the double-ended threaded rod;

[0025] Two sets of outer diameter measuring plates, each set of outer diameter measuring plates consists of a second vertical rod and a second cross rod, the top end of the second vertical rod is fixedly connected to one end of the second cross rod, and the second vertical rod is threadedly connected to the double-headed threaded rod;

[0026] An outer diameter scale, fitted with the second crossbar;

[0027] The outer diameter limiting rod is arranged at the bottom end of the second vertical rod and is rotatably connected to the second vertical rod.

[0028] Preferably, one end of the second cross bar away from the second vertical bar and an edge of the outer diameter limiting rod close to the exhaust pipe are on the same vertical line.

[0029] Preferably, the limiting device comprises:

[0030] Spur gears;

[0031] A driving assembly, fixedly connected to the axis of the spur gear, and used to drive the spur gear to rotate;

[0032] Two sets of racks, each set of racks is meshed and connected with the spur gear;

[0033] Two sets of moving plates, each set of moving plates is fixedly connected to one end of the rack away from the spur gear;

[0034] Two groups of electric push rods, each group of electric push rods is arranged above the moving plate;

[0035] Two groups of support plates, each group of support plates is arranged between the electric push rod and the shell, and the bottom end of the support plate is fixedly connected to the output end of the electric push rod.

[0036] Preferably, the two groups of racks are symmetrical along the axis center of the spur gear.

[0037] Preferably, it also includes: two groups of length measuring devices; each group of length measuring devices is fixedly connected to the shell and is used to measure the length of the exhaust pipe.

[0038] Preferably, each set of the length measuring devices comprises:

[0039] Two sets of length detection plates are fixedly connected to one side of the shell body close to the exhaust pipe;

[0040] The length scale is fitted with the length detection plate.

[0041] The beneficial effect proposed by the utility model is that by operating the limit device, the limit device will insert part of the structure of the inner diameter detection device into the exhaust pipe. At this time, the inner diameter detection device is operated to ensure that there is no gap between the inner diameter detection device and the exhaust pipe without causing scratches on the inner wall of the exhaust pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the structure of the utility model;

[0043] Figure 2 for Figure 1 Schematic diagram of the cross-section plane at the CC line;

[0044] Figure 3 for Figure 2 The right side view of the middle part of the connecting structure;

[0045] Figure 4 for Figure 3 Schematic diagram of the connection structure at B in the middle;

[0046] Figure 5 for Figure 3 Schematic diagram of the connection structure at B in the middle.

[0047] In the figure: 1. detection workbench, 2. exhaust pipe fixing plate, 3. exhaust pipe, 4. shell, 5. length detection plate, 6. transmission assembly, 7. turntable, 8. rotating block, 9. rotating rod, 10. inner diameter measuring plate, 11. inner diameter limiting rod, 12. inner diameter scale, 13. handwheel, 14. outer diameter measuring plate, 15. outer diameter scale, 16. outer diameter limiting rod, 17. double-headed threaded rod, 18. drive assembly, 19. spur gear, 20. rack, 21. moving plate, 22. electric push rod, 23. support plate, 24. length scale. DETAILED DESCRIPTION

[0048] The utility model is further described below in conjunction with the accompanying drawings: Example

[0049] See also Figure 1-5 In this embodiment: an exhaust pipe size detection device includes: a detection workbench 1, two sets of exhaust pipe fixing plates 2, a limiting device, two sets of inner diameter detection devices and two sets of outer diameter detection devices.

[0050] In this embodiment, two sets of exhaust pipe fixing plates 2 are both arranged above the detection workbench 1 to support the exhaust pipe 3 .

[0051] In this embodiment, the exhaust pipe fixing plate 2 can make the axis of the exhaust pipe 3 and the center of the shell 4 in the same plane.

[0052] The limiting device is arranged inside the detection workbench 1, and the limiting device comprises: two sets of shells 4, which are symmetrically arranged at both ends of the exhaust pipe 3, and are used to limit the exhaust pipe 3 at the middle position.

[0053] In this embodiment, the limiting device can make the middle position of the exhaust pipe 3 coincide with the zero mark of the length scale 24 .

[0054] Each set of inner diameter detection devices is arranged at the lower part of the shell 4 to detect the inner diameter of the exhaust pipe 3 ; each set of outer diameter detection devices is arranged at the upper part of the shell 4 to detect the outer diameter of the exhaust pipe 3 .

[0055] like Figure 3 and Figure 4 As shown, each set of inner diameter detection devices includes: a transmission assembly 6, a rotating disk 7, two sets of rotating blocks 8, two sets of rotating rods 9, two sets of inner diameter measuring plates 10, an inner diameter scale 12 and two sets of inner diameter limiting rods 11.

[0056] In this embodiment, the transmission assembly 6 is composed of a belt and two sets of pulleys, the belt is arranged on the edges of the two sets of pulleys; the turntable 7 is coaxially arranged with a set of pulleys; the center of each set of rotating blocks 8 is fixedly connected to the axis of the pulley.

[0057] In this embodiment, when the turntable 7 rotates, it will drive a group of pulleys to rotate. This group of pulleys drives another group of pulleys to rotate in the same direction through belts, and the rotation speed and rotation angle are the same. The two groups of pulleys drive the two groups of rotating blocks 8 to rotate at the same time.

[0058] A through hole is provided inside the rotating block 8; each set of rotating rods 9 is arranged in the through hole and is slidably connected to the rotating block 8 through the through hole; a baffle is provided on the surface of the rotating rod 9, and a spring is provided between the baffle and the rotating block 8 and is fitted on the rotating rod 9.

[0059] In this embodiment, when the rotating block 8 rotates, the rotating rod 9 is driven to rotate. When the space is insufficient, the rotating rod 9 slides along the through hole toward the rotating block 8 during the rotation process and compresses the spring.

[0060] A cylindrical pin is provided at one end of the rotating rod 9 away from the rotating block 8; each set of inner diameter measuring plates 10 consists of a first vertical rod and a first cross rod, and the bottom end of the first vertical rod is fixedly connected to one end of the first cross rod; a sliding groove is provided on the surface of the first vertical rod, and is slidably connected to the cylindrical pin through the sliding groove.

[0061] In this embodiment, when the rotating rod 9 rotates, the inner diameter measuring plate 10 will move horizontally through the sliding between the cylindrical pin and the slide groove. Since the slide groove length of the inner diameter measuring plate 10 is limited, when reaching the top or bottom of the slide groove, as the rotating rod 9 continues to rotate, the rotating rod 9 will slide along the through hole.

[0062] The surface of the inner diameter scale 12 fits with the first cross bar, and the zero scale of the inner diameter scale 12 coincides with the center of the shell 4; each group of inner diameter limiting rods 11 is arranged at the top of the first vertical rod and is rotatably connected to the first vertical rod; the end of the first cross bar away from the first vertical rod is on the same vertical line as the edge of the inner diameter limiting rod 11 close to the exhaust pipe 3.

[0063] In this embodiment, the inner radius of the exhaust pipe 3 can be known by observing the scale on the inner diameter scale 12 at the end of the first horizontal rod away from the first vertical rod.

[0064] When detecting the inner diameter, the user rotates the turntable 7, and the turntable 7 drives a group of pulleys to rotate; this group of pulleys drives another group of pulleys to rotate in the same direction through the belt; the two groups of pulleys drive the two groups of rotating blocks 8 to rotate at the same time; the rotating block 8 drives the rotating rod 9 to rotate; the rotating rod 9 slides between the cylindrical pin and the slide groove, so that the inner diameter measuring plate 10 moves horizontally; and because the slide groove length of the inner diameter measuring plate 10 is limited, when it reaches the top or bottom of the slide groove; as the rotating rod 9 continues to rotate, the rotating rod 9 will slide along the through hole; and compress the spring, and when there is space, the spring will rebound; the inner diameter measuring plate 10 drives the inner diameter limiting rod 11 to move; because the inner diameter limiting rod 11 is cylindrical, it can ensure that there is no gap between the inner diameter limiting rod 11 and the exhaust pipe 3, and will not cause scratches on the inner wall of the exhaust pipe 3; then by observing the scale on the inner diameter scale 12 at the end of the first horizontal rod away from the first vertical rod, the inner radius of the exhaust pipe 3 can be known.

[0065] A semicircular notch is provided at the top of the exhaust pipe fixing plate 2 .

[0066] like Figure 3 and Figure 5 As shown, each set of outer diameter detection devices includes: a double-headed threaded rod 17, a hand wheel 13, two sets of outer diameter measuring plates 14, an outer diameter scale 15 and an outer diameter limiting rod 16.

[0067] The double-threaded rod 17 penetrates the corresponding position of the housing 4 and is rotatably connected to the housing 4 ; the hand wheel 13 is fixedly connected to one end of the double-threaded rod 17 .

[0068] In this embodiment, by rotating the hand wheel 13 , the hand wheel 13 will drive the double-headed threaded rod 17 to rotate, and the housing 4 will support the rotation of the double-headed threaded rod 17 .

[0069] Each set of outer diameter measuring plates 14 is composed of a second vertical rod and a second cross rod. The top end of the second vertical rod is fixedly connected to one end of the second cross rod, and the second vertical rod is threadedly connected to the double-headed threaded rod 17 .

[0070] In this embodiment, since the thread directions of the two groups of double-threaded rods 17 are opposite, the two groups of outer diameter measuring plates 14 move toward the middle or toward the outside at the same time.

[0071] The outer diameter scale 15 fits the second cross bar, and the zero scale of the outer diameter scale 15 coincides with the center of the shell 4; the outer diameter limiting rod 16 is arranged at the bottom end of the second vertical rod and is rotatably connected to the second vertical rod; the end of the second cross bar away from the second vertical rod is on the same vertical line as the edge of the outer diameter limiting rod 16 close to the exhaust pipe 3.

[0072] In this embodiment, the outer radius of the exhaust pipe 3 can be known by observing the scale on the outer diameter scale 15 at the end of the second horizontal rod away from the second vertical rod.

[0073] When measuring the outer diameter, the user rotates the hand wheel 13; the hand wheel 13 drives the double-headed threaded rod 17 to rotate; the double-headed threaded rod 17 causes the two sets of outer diameter measuring plates 14 to move toward the middle at the same time; the outer diameter measuring plate 14 drives the outer diameter limiting rod 16 to move, and stops after the outer diameter limiting rod 16 is in contact with the outer wall of the exhaust pipe 3; at this time, the scale on the outer diameter scale 15 at the end of the second horizontal rod away from the second vertical rod can be observed to know the outer radius of the exhaust pipe 3, thereby completing the detection of the outer diameter of the exhaust pipe 3.

[0074] like Figure 2 As shown, the limiting device includes: a spur gear 19, a driving assembly 18, two groups of racks 20, two groups of moving plates 21, two groups of electric push rods 22 and two groups of support plates 23.

[0075] Specifically, the driving assembly 18 is fixedly connected to the axis of the spur gear 19 to drive the spur gear 19 to rotate.

[0076] In this embodiment, the driving assembly 18 is composed of a motor and two sets of bevel gears. The two sets of bevel gears are meshed and connected with each other. The output end of the motor drives the spur gear 19 to rotate through the two sets of bevel gears.

[0077] Each set of racks 20 is meshedly connected with the spur gear 19 ; each set of moving plates 21 is fixedly connected with one end of the racks 20 away from the spur gear 19 .

[0078] In this embodiment, when the spur gear 19 rotates, the two sets of racks 20 will move toward the middle or outward at the same time, and the racks 20 will push the moving plate 21 to move.

[0079] Each set of electric push rods 22 is arranged above the movable plate 21. The model of the electric push rods 22 is selected according to actual needs and meets the working conditions. Each set of support plates 23 is arranged between the electric push rods 22 and the shell 4, and the bottom end of the support plate 23 is fixedly connected to the output end of the electric push rod 22.

[0080] The two sets of racks 20 are symmetrical along the axis of the spur gear 19 .

[0081] When the exhaust pipe 3 is limited, the driving component 18 is started; the driving component 18 drives the spur gear 19 to rotate, and the spur gear 19 causes the two sets of racks 20 to move toward the middle at the same time, and the racks 20 drive the moving plate 21 to move, and the moving plate 21 drives the support plate 23 and the shell 4 to move through the electric push rod 22, and the shell 4 drives the length detection plate 5 to move, and pushes the exhaust pipe 3 to the middle position, thereby realizing the limitation of the position of the exhaust pipe 3.

[0082] The exhaust pipe size detection device further includes: two groups of length measuring devices; each group of length measuring devices is fixedly connected to the housing 4 and is used to measure the length of the exhaust pipe 3 .

[0083] In this embodiment, Figure 1 As shown, each set of length measuring devices includes: two sets of length detection plates 5 and a length scale 24.

[0084] Among them, two sets of length detection plates 5 are fixedly connected to one side of the shell 4 close to the exhaust pipe 3; the length scale 24 is fitted with the length detection plate 5, and by observing the scale of the length detection plate 5 on the length scale 24, half the length of the exhaust pipe 3 can be known.

[0085] Working principle:

[0086] When the exhaust pipe size detection device is in use, the exhaust pipe 3 is placed on the exhaust pipe fixing plate 2 and the driving component 18 is started; the driving component 18 drives the spur gear 19 to rotate, and the spur gear 19 causes the two sets of racks 20 to move toward the middle at the same time, and the racks 20 drive the moving plate 21 to move, and the moving plate 21 drives the support plate 23 and the shell 4 to move through the electric push rod 22, and the shell 4 drives the length detection plate 5 to move, and pushes the exhaust pipe 3 to the middle position, thereby limiting the position of the exhaust pipe 3.

[0087] At this time, by observing the scale of the length detection plate 5 on the length scale 24, the half length of the exhaust pipe 3 can be known.

[0088] At the same time, the inner diameter limiting rod 11 will be inserted into the exhaust pipe 3. The user rotates the turntable 7, which drives a group of pulleys to rotate. This group of pulleys drives another group of pulleys to rotate in the same direction through the belt. The two groups of pulleys drive the two groups of rotating blocks 8 to rotate at the same time. The rotating block 8 drives the rotating rod 9 to rotate. The rotating rod 9 slides between the cylindrical pin and the slide groove, so that the inner diameter measuring plate 10 moves horizontally. However, due to the limited length of the slide groove of the inner diameter measuring plate 10, when it reaches the top or bottom of the slide groove, as the rotating rod 9 continues to rotate, the rotating rod 9 will slide along the through hole, and compress the spring. When there is space, the spring will rebound. The inner diameter measuring plate 10 drives the inner diameter limiting rod 11 to move. Since the inner diameter limiting rod 11 is cylindrical, it can ensure that there is no gap between the inner diameter limiting rod 11 and the exhaust pipe 3, and will not cause scratches on the inner wall of the exhaust pipe 3. Then, by observing the scale of the end of the first horizontal rod away from the first vertical rod on the inner diameter scale 12, the inner radius of the exhaust pipe 3 can be known.

[0089] When measuring the outer diameter, the user rotates the hand wheel 13; the hand wheel 13 drives the double-headed threaded rod 17 to rotate; the double-headed threaded rod 17 causes the two sets of outer diameter measuring plates 14 to move toward the middle at the same time; the outer diameter measuring plate 14 drives the outer diameter limiting rod 16 to move, and stops after the outer diameter limiting rod 16 fits the outer wall of the exhaust pipe 3; at this time, the scale on the outer diameter scale 15 at the end of the second horizontal rod away from the second vertical rod is observed, and the outer radius of the exhaust pipe 3 can be known, and the detection of the outer diameter of the exhaust pipe 3 is completed, and the detection of the exhaust pipe 3 this time is completed.

[0090] Although the present invention has been shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein within the scope of the claims.

Claims

1. An exhaust pipe size detection device, characterized in that: include: Inspection bench (1); Two sets of exhaust pipe fixing plates (2) are both arranged above the detection workbench (1) and are used to support the exhaust pipe (3); A limiting device is arranged inside the detection workbench (1), the limiting device comprising: two sets of shells (4) symmetrically arranged at both ends of the exhaust pipe (3) and used to limit the exhaust pipe (3) to a middle position; Two sets of inner diameter detection devices, each set of inner diameter detection devices is arranged at the lower part of the interior of the shell (4) and is used to detect the inner diameter of the exhaust pipe (3); Two sets of outer diameter detection devices, each set of outer diameter detection devices is arranged above the interior of the shell (4) and is used to detect the outer diameter of the exhaust pipe (3).

2. The exhaust pipe size detection device according to claim 1, characterized in that: Each group of inner diameter detection devices comprises: A transmission assembly (6) is composed of a belt and two sets of pulleys, wherein the belt is arranged on the edges of the two sets of pulleys; A rotating disk (7) is coaxially arranged with a set of the pulleys; Two groups of rotating blocks (8), the center of each group of rotating blocks (8) being fixedly connected to the axis of the pulley; a through hole is provided inside the rotating block (8); Two groups of rotating rods (9), each group of rotating rods (9) is arranged in the through hole and is slidably connected to the rotating block (8) through the through hole; a baffle is arranged on the surface of the rotating rod (9), a spring is arranged between the baffle and the rotating block (8), and the spring is fitted and sleeved on the rotating rod (9); a cylindrical pin is arranged at one end of the rotating rod (9) away from the rotating block (8); Two sets of inner diameter measuring plates (10), each set of inner diameter measuring plates (10) consists of a first vertical rod and a first cross rod, the bottom end of the first vertical rod is fixedly connected to one end of the first cross rod; a sliding groove is provided on the surface of the first vertical rod, and the first vertical rod is slidably connected to the cylindrical pin through the sliding groove; An inner diameter scale (12), the surface of the inner diameter scale (12) being in contact with the first crossbar; Two groups of inner diameter limiting rods (11), each group of inner diameter limiting rods (11) is arranged at the top end of the first vertical rod and is rotatably connected to the first vertical rod.

3. The exhaust pipe size detection device according to claim 2, characterized in that: An end of the first cross bar away from the first vertical bar and an edge of the inner diameter limiting rod (11) close to the exhaust pipe (3) are located on the same vertical line.

4. The exhaust pipe size detection device according to claim 1, characterized in that: A semicircular notch is provided at the top end of the exhaust pipe fixing plate (2).

5. The exhaust pipe size detection device according to claim 1, characterized in that: Each set of the outer diameter detection device comprises: A double-ended threaded rod (17) passes through a corresponding position of the shell (4) and is rotatably connected to the shell (4); A hand wheel (13) fixedly connected to one end of the double-ended threaded rod (17); Two sets of outer diameter measuring plates (14), each set of outer diameter measuring plates (14) is composed of a second vertical rod and a second cross rod, the top end of the second vertical rod is fixedly connected to one end of the second cross rod, and the second vertical rod is threadedly connected to the double-headed threaded rod (17); An outer diameter scale (15) is fitted with the second crossbar; An outer diameter limiting rod (16) is arranged at the bottom end of the second vertical rod and is rotatably connected to the second vertical rod.

6. The exhaust pipe size detection device according to claim 5, characterized in that: An end of the second cross bar away from the second vertical bar and an edge of the outer diameter limiting rod (16) close to the exhaust pipe (3) are located on the same vertical line.

7. The exhaust pipe size detection device according to claim 1, characterized in that: The limiting device comprises: Spur gear (19); A driving assembly (18) fixedly connected to the axis of the spur gear (19) and used to drive the spur gear (19) to rotate; Two sets of racks (20), each set of racks (20) being meshingly connected with the spur gear (19); Two groups of movable plates (21), each group of movable plates (21) being fixedly connected to an end of the rack (20) away from the spur gear (19); Two groups of electric push rods (22), each group of electric push rods (22) is arranged above the movable plate (21); Two groups of support plates (23), each group of support plates (23) is arranged between the electric push rod (22) and the housing (4), and the bottom end of the support plate (23) is fixedly connected to the output end of the electric push rod (22).

8. The exhaust pipe size detection device according to claim 7, characterized in that: The two groups of racks (20) are symmetrical along the axis center of the spur gear (19).

9. The exhaust pipe size detection device according to claim 1, characterized in that: Also includes: Two sets of length measuring devices; each set of length measuring devices is fixedly connected to the housing (4) and is used to measure the length of the exhaust pipe (3).

10. The exhaust pipe size detection device according to claim 9, characterized in that: Each set of the length measuring devices comprises: Two sets of length detection plates (5) are fixedly connected to a side of the housing (4) close to the exhaust pipe (3); The length scale (24) is fitted onto the length detection plate (5).

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