Half-shaft gear backlash measuring device

Abstract

This application provides a half-shaft gear backlash measuring device, which includes a connecting shaft core, a positioning block, a measuring gauge, and at least two spaced-apart expansion plates. The measuring gauge is fixed on the positioning block. The positioning block has a connecting groove, and one end of each expansion plate is engaged in the connecting groove. The connecting shaft core is movably mounted on the positioning block, and the expansion plates surround the connecting shaft core. The connecting shaft core can move along its axis to abut against the expansion plates, forcing them to open. Therefore, by engaging the expansion plates with the positioning block, disassembly and installation are convenient, making the entire half-shaft gear backlash measuring device easy to carry when not in use. Furthermore, engaging the expansion plates with the positioning block facilitates the replacement of expansion plates when measuring different types of half-shaft gears, thus improving compatibility.

Description

Technical Field

[0001] This application relates to the field of mechanical inspection tools, and in particular to a device for measuring the clearance of expansion plates and half-shaft gears. Background Technology

[0002] During differential operation, excessive axial clearance of the half-shaft gears can negatively impact the vehicle's NVH (noise, vibration, and harshness) performance, resulting in significant noise during transmission. Conversely, insufficient axial clearance can cause uneven gear operation within the differential, leading to excessive heat generation and potential gear jamming and burning. Existing differential axial clearance measurement devices are either large, specialized, or integrated units. Large devices are bulky, typically used for offline testing, expensive, and inconvenient to carry. Integrated specialized devices are limited to specific products and have poor compatibility. Summary of the Invention

[0003] To solve the above-mentioned technical problems, this application provides a device for measuring the clearance of expansion plates and half-shaft gears, which is easy to carry and highly adaptable.

[0004] One aspect of this application provides a half-shaft gear backlash measuring device, including a connecting shaft core, a positioning block, a measuring gauge, and at least two spaced-apart expansion plates; the measuring gauge is fixed on the positioning block; the positioning block is provided with a connecting groove, and one end of each expansion plate is engaged in the connecting groove; the connecting shaft core is movably mounted on the positioning block, and the expansion plates surround the connecting shaft core; wherein the connecting shaft core can move along its axis to abut against the expansion plates and force the expansion plates to open.

[0005] Furthermore, each of the expansion pieces has a cross-section along its length including at least two connecting segments with different curvatures.

[0006] Furthermore, each of the expansion pieces includes an inner wall facing the connecting shaft core and an outer wall facing away from the connecting shaft core, wherein the connecting shaft core is movable to abut against the inner wall; at least one of the inner wall and the outer wall includes at least two connecting segments with different curvatures.

[0007] Furthermore, the thickness of the cross-section of each of the expansion pieces is not equal, and each of the outer sidewalls includes a first connecting segment, a second connecting segment and a third connecting segment connected in sequence, wherein the curvature of the first connecting segment and the third connecting segment is the same, and the curvature of the second connecting segment is less than the curvature of the first connecting segment.

[0008] Furthermore, each of the inner sidewalls includes a fourth connecting segment, a fifth connecting segment, and a sixth connecting segment connected in sequence. The curvature of the fourth connecting segment is the same as that of the sixth connecting segment, and the curvature of the fifth connecting segment is greater than that of the fourth connecting segment.

[0009] Furthermore, the curvature of the second connecting segment is less than the curvature of the fourth connecting segment.

[0010] Furthermore, there are multiple connecting slots, and the expansion piece can be selectively engaged in one of the multiple connecting slots.

[0011] Furthermore, there are two connecting grooves, namely a first connecting groove and a second connecting groove. Both the first connecting groove and the second connecting groove are annular grooves, and the first connecting groove surrounds the outside of the second connecting groove. The first connecting groove and / or the second connecting groove are inclined.

[0012] Furthermore, the inclination angle of the outer wall of the first connecting groove or the second connecting groove is in the range of 3°-3.5°.

[0013] Furthermore, the connecting shaft core includes an expansion core and a screw, the screw extending from the upper end face of the expansion core; the positioning block is provided with a connecting hole, the screw engaging with the connecting hole; the expansion core moves with the screw and forces each of the expansion plates to open.

[0014] Furthermore, it also includes a nut, which is connected to the screw, and the nut is located on the side of the positioning block opposite to the expansion core.

[0015] Furthermore, the measuring instrument is a dial indicator, which is fixed on the positioning block, and the measuring head of the dial indicator extends out of the positioning block.

[0016] The beneficial effects of this application are as follows: The half-shaft gear backlash measuring device proposed in this application includes a connecting shaft core, a positioning block, a measuring gauge, and at least two spaced-apart expansion plates; the measuring gauge is fixed on the positioning block; the positioning block is provided with a connecting groove, and one end of each expansion plate is engaged in the connecting groove; the connecting shaft core is movably mounted on the positioning block, and the expansion plates surround the connecting shaft core; wherein, the connecting shaft core can move along its axis to abut against the expansion plates and force the expansion plates to open. Therefore, by engaging the expansion plates with the positioning block, disassembly and installation are convenient, making the entire half-shaft gear backlash measuring device easy to carry when not in use. Furthermore, engaging the expansion plates with the positioning block facilitates the replacement of expansion plates when measuring different models of half-shaft gears, thus improving its adaptability. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0018] Figure 1 This is a three-dimensional structural schematic diagram of a half-shaft gear clearance measuring device provided in this application. The half-shaft gear clearance measuring device includes an expansion plate, wherein the expansion plate is engaged in a second connecting groove.

[0019] Figure 2 yes Figure 1 A three-dimensional structural diagram of the expansion plate;

[0020] Figure 3 yes Figure 1 A top-view structural diagram;

[0021] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure along the AA direction;

[0022] Figure 5 yes Figure 1 A cross-sectional view of the expansion plate being mounted in the first connecting groove;

[0023] Figure 6 yes Figure 1 A partial cross-sectional view of the structure, including two expansion plates respectively fitted into the first connecting groove and the second connecting groove. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0025] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0026] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] One aspect of this application provides a half-shaft gear clearance measuring device 100, with reference to... Figure 1 , Figure 3 and Figure 4 , Figure 1 This is a three-dimensional structural schematic diagram of a half-shaft gear clearance measuring device provided in this application. The half-shaft gear clearance measuring device includes an expansion plate, wherein the expansion plate is engaged in a second connecting groove. Figure 3 yes Figure 1 A top-view structural diagram; Figure 4 yes Figure 2 A cross-sectional view along the AA direction. The half-shaft gear clearance measuring device 100 includes a connecting shaft core 1, a positioning block 2, a measuring gauge 3, and at least two spaced expansion plates 4.

[0028] The positioning block 2 contacts the differential housing and serves as a positioning element during the use of the half-shaft gear clearance measuring device 100. The measuring gauge 3 is fixed to the positioning block 2. Therefore, during use, the positioning block 2 is first brought into contact with the differential housing to determine its relative position to the differential, and then the initial measurement value is obtained using the measuring gauge 3.

[0029] The positioning block 2 is provided with a connecting groove 21, and one end of each expansion piece 4 is engaged in the connecting groove 21. The expansion pieces 4 are easily disassembled, installed, and replaced by engaging in the connecting groove 21, thus adapting to different products and effectively improving their compatibility. The connecting shaft core 1 is movably mounted on the positioning block 2, meaning that after the connecting shaft core 1 is installed and connected to the positioning block 2, it can also move relative to the positioning block 2. The expansion pieces 4 surround the connecting shaft core 1, and the connecting shaft core 1 can move along its axis to abut against the expansion pieces 4, forcing the expansion pieces 4 to open. In other words, when the connecting shaft core 1 moves relative to the positioning block 2, it can abut against the expansion pieces 4, and even cause the expansion pieces 4 to open under the action of the connecting shaft core 1, thereby abutting against the spline of the half-shaft gear in the differential, and driving the half-shaft gear to move together under the action of friction.

[0030] Therefore, the half-shaft gear clearance measuring device 100 in this application, by snapping the expansion plate 4 with the positioning block 2, facilitates the disassembly and installation of the expansion plate 4 and the positioning block 2, making the entire half-shaft gear clearance measuring device 100 easy to carry after disassembly when not in use. Furthermore, snapping the expansion plate 4 with the positioning block 2 allows for easy replacement of the expansion plate 4 when measuring different types of half-shaft gears, thus improving its adaptability. For example, different operating conditions result in different spline parameters for the half-shaft gears of the differential, requiring the use of different specifications of half-shaft gear clearance measuring devices 100 for measurement. Small-diameter bevel gears cannot be used The bushing measuring device is used for locking measurement. Because the opening range of the bushing measuring device is 0.5mm, its adaptability is poor. Therefore, a multi-specification half-shaft gear clearance measuring device 100 is needed to measure different differentials.

[0031] Please see Figure 2 , Figure 4 , Figure 5 and Figure 6 , Figure 2 yes Figure 1 A three-dimensional structural diagram of the expansion plate; Figure 5 yes Figure 1 A cross-sectional view of the expansion plate being mounted in the first connecting groove; Figure 6 yes Figure 1 The diagram shows a partial cross-sectional view of two expansion tabs respectively engaged in a first connecting groove and a second connecting groove. In some embodiments, the cross-section of each expansion tab 4 along its length includes at least two connecting segments with different curvatures. It is understood that by setting the cross-sections of the expansion tabs 4 with different curvatures along their length, during the connection process with the connecting groove 21, only the connecting segment with the same curvature as the connecting groove 21 abuts against the connecting groove 21 and is connected together by friction between them. This makes it easy for the expansion tabs 4 to be engaged within the connecting groove 21, and in some applications, it also allows one expansion tab 4 to be connected at different positions on the positioning block 2.

[0032] Please continue reading. Figure 2 , Figure 4 and Figure 5In some embodiments, each expansion piece 4 includes an inner wall 41 facing the connecting shaft core 1 and an outer wall 42 facing away from the connecting shaft core 1. The connecting shaft core 1 is movable to abut against the inner wall 41. It is understood that the connecting shaft core 1 may initially abut against the inner wall 41 of the expansion piece 4, or may not abut against it, as long as it abuts against the inner wall 41 of the expansion piece 4 during movement of the connecting shaft core 1, causing the expansion piece 4 to open. At least one of the inner wall 41 and the outer wall 42 includes at least two connecting segments with different curvatures, abutting against the connecting groove 21 via the inner wall 41 of the expansion piece 4, and / or abutting against the connecting groove 21 via the outer wall 42 of the expansion piece 4, utilizing the frictional force between the two abutting to engage the expansion piece 4 within the connecting groove 21. In addition, by setting a connecting section with different curvatures on one side wall, a bulge 4 can be matched with a connecting groove 21 with different curvatures, thereby matching with the same or different connecting shafts, so that the half shaft gear clearance measuring device 100 can adapt to differentials of different sizes and specifications.

[0033] In some embodiments, the thickness of the cross-section of each expansion piece 4 is not uniform. Each outer wall 42 includes a first connecting segment 421, a second connecting segment 422, and a third connecting segment 423 connected in sequence. The first connecting segment 421 and the third connecting segment 423 have the same curvature, while the curvature of the second connecting segment 422 is less than that of the first connecting segment 421. That is, during the engagement with the connecting groove 21, the first connecting segment 421 and the second connecting segment 422 work together, while the second connecting segment 422 works independently.

[0034] Optionally, each expansion piece 4 has the same cross-sectional thickness. Each outer wall 42 includes a first connecting segment 421, a second connecting segment 422, and a third connecting segment 423 connected in sequence. The first connecting segment 421 and the third connecting segment 423 have the same curvature, while the curvature of the second connecting segment 422 is less than that of the first connecting segment 421. That is, during the engagement with the connecting groove 21, the first connecting segment 421 and the second connecting segment 422 act together, while the second connecting segment 422 acts alone. It is understood that different cross-sectional thicknesses of the expansion pieces 4 are more suitable for connecting grooves 21 with constant curvature, such as an annular groove; while the same cross-sectional thickness of the expansion pieces 4 is more suitable for connecting grooves 21 with different curvatures.

[0035] In some embodiments, each inner sidewall 41 includes a fourth connecting segment 411, a fifth connecting segment 412, and a sixth connecting segment 413 connected in sequence. The curvature of the fourth connecting segment 411 and the sixth connecting segment 413 are the same, while the curvature of the fifth connecting segment 412 is greater than that of the fourth connecting segment 411. During engagement with the connecting groove 21, the fourth connecting segment 411 and the sixth connecting segment 413 work together, while the fifth connecting segment 412 works independently.

[0036] It is understandable that when both the inner wall 41 and the outer wall 42 are provided with at least two connecting segments with different curvatures, the expansion piece 4 can be securely engaged in the connecting groove 21 by the cooperation of the connecting segments of the inner and outer walls 42. In some embodiments, the curvature of the second connecting segment 422 is less than the curvature of the fourth connecting segment 411. Thus, during the use of the expansion piece 4, the first connecting segment 421, the third connecting segment 423, and the fifth connecting segment 412 work together to abut against the inner wall of the connecting groove 21, so that the expansion piece 4 is securely engaged in the connecting groove 21; or the second connecting segment 422, the fourth connecting segment 411, and the sixth connecting segment 413 work together to abut against the inner wall of the connecting groove 21, so that the expansion piece 4 is securely engaged in the connecting groove 21.

[0037] It should be noted that the inner wall 41 of the cross-section along the length of the expansion piece 4 includes the first connecting segment 421, the second connecting segment 422, and the third connecting segment. Alternatively, the third connecting segment may be included only in a portion of the cross-section along the length, as long as the expansion piece 4 can be engaged in the connecting groove 21, abut against the connecting groove 21, and remain engaged in the connecting groove 21 even when subjected to the abutment of the connecting shaft. Similarly, the outer wall 42 of the cross-section along the length of the expansion piece 4 includes or partially includes the fourth connecting segment 411, the fifth connecting segment 412, and the sixth connecting segment 413.

[0038] It is also understandable that the inner wall 41 of the end of the expansion piece 4 that abuts against and opens with the connecting shaft core 1 is provided with a transition surface 414. The transition surface 414 can be provided along the width direction of the expansion piece 4 and is inclined in the length direction. That is, the transition surface 414 makes the thickness of the end of the expansion piece 4 that abuts against and opens with the connecting shaft core 1 gradually decrease. Thus, when it abuts against the connecting shaft core 1, it is in surface contact, which strengthens the interaction between the two.

[0039] In some embodiments, there are multiple connecting slots 21, and the expansion plate 4 can be selectively engaged in one of the multiple connecting slots 21. Thus, during use, the same expansion plate 4 engaged in different connecting slots 21 can be used for differentials of different sizes and specifications, thereby increasing the adaptability of the half-shaft gear clearance measuring device 100.

[0040] Please see Figures 4-6In some specific embodiments, the connecting groove 21 is an annular groove, specifically a circular annular groove. There are two connecting grooves 21, namely a first connecting groove 211 and a second connecting groove 212, with the first connecting groove 211 surrounding the second connecting groove 212. It can be understood that the first connecting groove 211 and the second connecting groove 212 can be concentric annular grooves, surrounding the connecting shaft. The expansion plate 4 can be selectively engaged in either the first connecting groove 211 or the second connecting groove 212. Since the first connecting groove 211 and the second connecting groove 212 have different radii, that is, different curvatures, when the expansion plate 4 is engaged in the second connecting groove 212, it can be used for differentials with smaller dimensions, that is, it can be connected with half-shaft gears with smaller dimensions. At this time, the first connecting segment 421 and the third connecting segment 423 of the expansion plate 4 abut against the outer wall of the second connecting groove 212, and the fifth connecting segment 412 abuts against the inner wall of the second connecting groove 212 or the outer wall of the connecting shaft core 1. When the expansion plate 4 is engaged in the first connecting groove 211, it can be used for differentials with larger dimensions. At this time, the second connecting section 422 abuts against the outer wall of the first connecting groove 211, and the fourth connecting section 411 and the sixth connecting section 413 abut against the inner wall of the first connecting groove 211. Thus, different sizes of reducers can still be used without replacing the expansion plate 4 or the connecting shaft.

[0041] To make the expansion piece 4 easier to open during the movement of the connecting shaft, the first connecting groove 211 and / or the second connecting groove 212 can be inclined. Preferably, the outer walls of the first connecting groove 211 and the second connecting groove 212 can be inclined.

[0042] It should be noted that one or more connecting grooves 21 can be provided on the positioning block 2 as needed. Furthermore, the connecting groove 21 is not limited to annular grooves; it can also consist of multiple sub-connecting grooves 21 spaced apart and surrounding the connecting shaft core 1, all of which can accommodate differentials of different sizes and specifications through the cooperation of the expansion plate 4, connecting groove 21, and connecting shaft core.

[0043] In some specific embodiments, the depth of the second connecting groove 212 is greater than the depth of the first connecting groove 211, thereby accommodating differentials of different sizes and specifications.

[0044] In some embodiments, the inclination angle of the outer walls of the first connecting groove 211 and / or the second connecting groove 212 ranges from 3° to 3.5°. For details, please refer to... Figure 5 Angle a in the middle.

[0045] In some embodiments, the connecting shaft core 1 includes an expansion core 11 and a screw 12, with the screw 12 extending from the upper end face of the expansion core 11. That is, the connecting shaft core 1 is integrally formed. The connecting shaft core 1 has a helical shape in the direction of movement relative to the positioning block 2. The positioning block 2 is provided with a connecting hole 22, and the screw 12 is connected to the connecting hole 22. The expansion core 11 moves with the screw 12, forcing each expansion piece 4 to open. The connecting hole 22 can communicate with the second connecting groove 212, so that when the expansion piece 4 is engaged in the second connecting groove 212, the fourth connecting section 411 directly abuts against the outer wall of the screw 12. It is understood that the connecting hole 22 is provided with an internal thread, and the screw 12 is provided with an external thread. Thus, the connecting shaft core 1 can move along the axial direction of the connecting hole 22 through the engagement of the internal and external threads, thereby causing the expansion core 11 to abut against the expansion piece 4 and forcing the expansion piece 4 to open.

[0046] It is understood that the expansion core 11 can be a frustum, and the screw 12 extends outward from the smaller end of the frustum. The side wall of the frustum connecting the shaft core 1 abuts against the expansion piece 4, forcing the expansion piece 4 to open. It is understood that frustums of different sizes or tapers can be used to cooperate with the expansion pieces 4 that are engaged in different connecting grooves 21 (see [reference]). Figure 4 The expansion piece 4 is engaged in the second connecting groove 212, and the frustum of the connecting shaft core 1 that mates with the expansion piece 4 has a relatively large taper. Please refer to [link / reference]. Figure 5 The expansion plate 4 is engaged in the first connecting groove 211, and the taper of the frustum of the connecting shaft core 1 that mates with the expansion plate 4 is relatively small, so as to accommodate reducers of different sizes and specifications. In other embodiments, the expansion core 11 can also be a frustum of a pyramid, such as a quadrangular pyramid, as long as it can force the expansion plate 4 to open during relative movement with the positioning block 2.

[0047] In some specific embodiments, the half-shaft gear backlash measuring device 100 further includes a nut 5, which is connected to the screw 12. The nut 5 is positioned on the side of the positioning block 2 opposite to the expansion core 11. That is, the threaded rod can be connected to the nut 5 and positioned on the positioning block 2 to form a lead screw structure. The distance between the expansion core 11 and the positioning block 2 can be adjusted by rotating the nut 5 to open the expansion plate 4. It is understood that when the nut 5 is connected to the threaded rod, the connecting hole 22 can be a through hole without the need for internal threads.

[0048] In some embodiments, the measuring instrument 3 is a dial indicator, which is fixed to the positioning block 2. The measuring head 31 of the dial indicator extends out of the positioning block 2 and can abut against the differential housing when the positioning block 2 abuts against the differential housing to obtain the original measurement value. The positioning block 2 is also provided with a fixing member 6, which is used to adjust the length of the measuring head 31 exposed on the positioning block 2 and to fix the measuring instrument 3 to the positioning block 2. It is understood that the fixing member 6 can be arranged in a direction perpendicular to the measuring instrument 3 and threadedly connected to the positioning block 2, with one end of the fixing member 6 operably abutting against the measuring instrument 3.

[0049] Specifically, when the differential is in its normal position, the upper and lower half-shaft gears will be tightly engaged together due to gravity, with the lower half-shaft gear pressed against the positioning surface. At this time, a gap will be created between the upper half-shaft gear and the upper positioning surface. This gap is the axial meshing gap of the half-shaft gear during the operation of the differential, that is, the distance that the gear set can move axially during the operation of the differential. In this state, the expansion plate 4 and the expansion core 11 are placed into the differential, so that the positioning block 2 contacts and positions itself with the differential housing. The fixing piece 6 is adjusted so that the measuring head 31 contacts the end face of the differential housing. At this time, the original measurement value of the dial indicator can be recorded, that is, the position of the upper half-shaft gear. The fixing piece 6 is adjusted and the dial indicator is fixed, and the expansion core 11 is adjusted. Because the expansion core 11 has a taper, the expansion plate 4 will be gradually expanded until it is fully engaged with or locked against the spline part of the upper half-shaft gear. At this time, the half-shaft gear clearance measuring device 100 and the upper half-shaft gear can be regarded as an integral structure. Then, the half-shaft gear clearance measuring device 100 is lifted upward until the upper half-shaft gear contacts the upper positioning surface. Next, adjust the fixing piece 6 so that the measuring head 31 of the dial indicator is in contact with the differential housing, and record the current measurement value. Finally, subtract the original measurement value from the current measurement value to obtain the axial clearance of the differential half-shaft gear.

[0050] In the description of this application, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A device for measuring the backlash of a half-shaft gear, characterized in that, Includes a connecting shaft, a positioning block, a measuring gauge, and at least two spaced expansion plates; The measuring instrument is fixed on the positioning block; The positioning block is provided with a connecting groove, and one end of each expansion piece is engaged in the connecting groove; The connecting shaft is movably mounted on the positioning block, and the expansion plate surrounds the connecting shaft; wherein the connecting shaft can move along its axis to abut against the expansion plate and force the expansion plate to open; Each of the expansion pieces has a cross-section along its length including at least two connecting segments with different curvatures; There are two connecting grooves, namely a first connecting groove and a second connecting groove. Both the first connecting groove and the second connecting groove are annular grooves, and the first connecting groove surrounds the second connecting groove. The first connecting groove and / or the second connecting groove are inclined. Each of the expansion pieces includes an inner wall facing the connecting shaft core and an outer wall facing away from the connecting shaft core, wherein the connecting shaft core is movable to abut against the inner wall; at least one of the inner wall and the outer wall includes at least two connecting segments with different curvatures; The thickness of the cross section of each of the expansion pieces is not equal, and each of the outer side walls includes a first connecting segment, a second connecting segment and a third connecting segment connected in sequence, wherein the curvature of the first connecting segment and the third connecting segment is the same, and the curvature of the second connecting segment is less than the curvature of the first connecting segment. Each of the inner sidewalls includes a fourth connecting segment, a fifth connecting segment, and a sixth connecting segment connected in sequence. The curvature of the fourth connecting segment is the same as that of the sixth connecting segment, and the curvature of the fifth connecting segment is greater than that of the fourth connecting segment. The curvature of the second connecting segment is less than that of the fourth connecting segment.

2. The axle gear clearance measuring device according to claim 1, characterized in that, There are multiple connecting slots, and the expansion plate is engaged in one of the multiple connecting slots.

3. The axle gear clearance measuring device according to claim 1, characterized in that, The inclination angle of the outer wall of the first connecting groove or the second connecting groove is in the range of 3°-3.5°.

4. The axle gear clearance measuring device according to claim 1, characterized in that, The connecting shaft core includes an expansion core and a screw, the screw extending from the upper end face of the expansion core; The positioning block is provided with a connecting hole, and the screw is connected to the connecting hole; the expansion core moves with the screw and forces each of the expansion pieces to open.

5. The axle gear clearance measuring device according to claim 4, characterized in that, It also includes a nut, which is connected to the screw, and the nut is located on the side of the positioning block opposite to the expansion core.

6. The axle gear clearance measuring device according to claim 1, characterized in that, The measuring instrument is a dial indicator, which is fixed on the positioning block, and the measuring head of the dial indicator extends out of the positioning block.

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