A friction arc length measuring scale and a friction arc length measuring method

Abstract

The application provides a friction arc length measuring scale for measuring the friction arc length of a disc brake device, comprising a first transverse measuring part, a second transverse measuring part and a longitudinal measuring part, the first transverse measuring part and the second transverse measuring part are arranged in parallel, and the longitudinal measuring part is perpendicular to the first transverse measuring part and the second transverse measuring part, the first transverse measuring part is used for measuring the chord length of the friction arc of a brake pad at a measuring point, the second transverse measuring part is used for measuring the chord length of the outer edge of a brake disc, and the longitudinal measuring part is used for measuring a first distance and / or a second distance, the first distance is the distance between the first transverse measuring part and the second transverse measuring part, and the second distance is the distance between the intersection point of the first transverse measuring part and the edge of the brake disc in the direction perpendicular to the first transverse measuring part. The application also provides a corresponding friction arc length measuring method. The application adopts a split design, has good adaptability, a wide application range and high measuring precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of measurement technology, and in particular to a circular arc length measuring scale and a disc-shaped brake friction arc length measuring method. BACKGROUND

[0002] When a train is in emergency braking, the brake pad and the brake disc convert the kinetic energy of the vehicle into heat energy through mutual friction and dissipate it, and when a high-speed motor train set is braking, the disc surface temperature can reach 900-1000℃, and high temperature will reduce the ability of the vehicle to stabilize braking. Using friction arc length to study the temperature distribution and changes during braking is the most direct, accurate and objective research method.

[0003] Friction arc length refers to the circular arc formed on the brake disc by the friction of a certain point on the brake pad. In practical application environments, a pair of brake pads is composed of multiple brake blocks, and it is usually necessary to measure the friction arc length of the brake disc covered by each brake block on a circular arc of a certain radius and sum up the total arc length at the radius. When selecting a measurement point, the user needs to specify the friction position (a point or a friction radius) according to the user's measurement requirements, i.e. a certain point in the friction area. According to this point (or friction radius), a circle is drawn, and after the circle is cut by the brake pad, another end point is formed, and the circular arc between the two points is the measured circular arc, and the measured point is on the same friction circular ring.

[0004] When the brake pad and the brake disc are in friction, the brake pad and the brake disc are in surface contact, and the friction arc length is different on the circumference with different friction radii, and the temperature is different. Friction arc length is the main parameter affecting the distribution of friction heat. When the friction surface is in good contact, the temperature is relatively higher in the area with a large total arc length, and the temperature is relatively lower in the area with a small friction arc length. Researchers usually measure the friction arc length at different radius positions in the friction area to guide the design of the brake pad. In order to ensure good friction efficiency, researchers need to make the temperature distribution on the brake disc as uniform as possible to avoid excessive concentration of heat to generate strong thermal stress and thus produce thermal cracks and other damages. At this time, it is necessary to accurately and conveniently measure the friction arc length.

[0005] The existing technology mainly includes the following schemes for measuring friction arc length: Figure 1As shown, first, a disc is made, the center of the disc coincides with the brake disc, and the radius of the disc is equal to the circumferential radius at the point to be measured. After the brake disc is removed from the installation environment, the disc is kept concentric and close to the brake disc, and a non-elastic string is used along the edge of the disc from the point to be measured to the other intersection point of the disc and the brake pad. The length between the two points is the length of the friction arc. However, this method is limited by the manual operation during measurement, and the arc length measurement accuracy is low and the efficiency is low. Moreover, the scheme must disassemble the brake disc from the shaft, and different radii of the disc must be made when measuring the friction arc length of different friction radii. Moreover, factors such as the thickness of the string and the thickness of the brake pad still affect the measurement accuracy, and the measurement method is unreliable.

[0006] Patent CN208026173U proposes a telescopic arc length measuring ruler, which includes a horizontal rod, a vertical rod and a cross connecting piece. The horizontal rod and the vertical rod are both composed of telescopic rods. The middle part of the horizontal rod is fixedly connected with the horizontal segment of the cross connecting piece, and the middle part of the vertical rod is fixedly connected with the vertical segment of the cross connecting piece. The two ends of the telescopic rod are telescopic, and the middle part of the telescopic rod is provided with a U-shaped groove. The groove width of the U-shaped groove matches the width of the telescopic rod, and the groove depth of the U-shaped groove is half of the thickness of the telescopic rod. The rod body of the telescopic rod is further provided with a measurement scale, and the starting point of the measurement scale extends from the middle part of the rod body to the two ends of the rod body. However, the measurement tool cannot adapt to the measurement of brake pads of different thicknesses, the measurement efficiency is low, the measurement accuracy is difficult to guarantee, and the measurement tool cannot be used to measure the friction arc length formed by the relative friction between the brake pad and the brake disc. SUMMARY

[0007] The main purpose of the present application is to provide a friction arc length measuring ruler and a friction arc length measuring method to solve the problems of inconvenient measurement of friction arc length, measurement tools that cannot adapt to different sizes of test pieces, low measurement efficiency, and difficult to guarantee measurement accuracy in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a friction arc length measuring ruler is provided for measuring the length of the friction arc formed by the mutual friction between the brake disc and the brake pad, which comprises a first transverse measuring part, a second transverse measuring part and a longitudinal measuring part. The first transverse measuring part and the second transverse measuring part are arranged in parallel, and the longitudinal measuring part is perpendicular to the first transverse measuring part and the second transverse measuring part. The first transverse measuring part is used to measure the chord length of the friction arc of the brake pad at the point to be measured, the second transverse measuring part is used to measure the chord length of the outer edge of the brake disc, and the longitudinal measuring part is used to measure the first distance and / or the second distance. The first distance is the distance between the first transverse measuring part and the second transverse measuring part; and the second distance is the distance between the first transverse measuring part and the intersection point of the brake disc edge in the direction perpendicular to the first transverse measuring part.

[0009] Further, the first lateral measuring part, the second lateral measuring part and the longitudinal measuring part each have a scale, the first lateral measuring part and the second lateral measuring part have the same center line, the center line is perpendicular to the first lateral measuring part and the second lateral measuring part, and the scales on the first lateral measuring part and the second lateral measuring part are symmetrically distributed relative to the center line.

[0010] Further, the longitudinal measuring part is fixed to the first lateral measuring part and arranged along the center line, the second lateral measuring part has a fixed part located at the center line, the fixed part is movably connected with the longitudinal measuring part, and the relative distance between the fixed part and the longitudinal measuring part is adjustable.

[0011] Further, the fixed part is arranged in parallel with the longitudinal measuring part, the fixed part is provided with a longitudinal guide part in parallel with the longitudinal measuring part, the longitudinal measuring part is provided with a fixing assembly, and the longitudinal measuring part is slidably connected to the longitudinal guide part on the fixed part through the fixing assembly.

[0012] Further, the fixing assembly includes two or more than two bolts and a plurality of nuts matched with the bolts.

[0013] Further, one or more of the longitudinal measuring part, the fixed part, the first lateral measuring part and the second lateral measuring part is made of transparent material, and the scale includes scale lines and scale values.

[0014] Further, the first lateral measuring part has a first lateral guide part, the second lateral measuring part has a second lateral guide part, the first lateral guide part is provided with a first lateral positioning assembly, the second lateral guide part is provided with a second lateral positioning assembly, the first lateral positioning assembly is used for positioning the first lateral guide part and the brake pad, and the second lateral positioning assembly is used for positioning the second lateral guide part and the outer edge of the brake disc.

[0015] Further, the first lateral positioning assembly and the second lateral positioning assembly each include two or more than two bolts and nuts matched with the bolts.

[0016] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a method for measuring the friction arc length of the brake pad on the brake disc using the friction arc length measuring ruler is provided, which includes a positioning step, a reading step and a calculation step,

[0017] In the positioning step, the to-be-measured point at the edge of the brake pad is taken as a first point, the edge of the first lateral measuring part on the side with the scale is kept coincident with the first point, the friction arc length measuring scale is rotated and / or the position of the second lateral measuring part in the radial direction of the brake disc is adjusted and / or the distance between the first point and the longitudinal measuring part is adjusted, so that the second lateral measuring part intersects with the outer edge of the brake disc to form a second point and a third point, and the scales at the second point and the third point are the same, and the other side of the center line of the first lateral measuring part intersects with the edge of the brake pad to form a fourth point; in the reading step, the scale at the first point and / or the fourth point is read, the scale at the second point and / or the third point is read, and the scale of the first distance or the second distance measured by the longitudinal measuring part is read; in the calculating step, the scales read in the reading step and the size of the brake disc are used to calculate the friction arc length.

[0018] Further, the distance adjustment step is further included and is performed before the positioning step, in which the relative distance between the first lateral measuring part and the second lateral measuring part in the axial direction of the brake disc is adjusted, so that the second lateral measuring part is close to the brake disc and the first lateral measuring part is close to the brake pad, and meanwhile, the first lateral measuring part and the second lateral measuring part remain parallel, so that the friction arc length measuring scale is adapted to the thickness of the brake pad.

[0019] Further, the second lateral measuring part is provided with a fixed part located at the center line, the fixed part is movably connected with the longitudinal measuring part, and the fixed part is provided with a longitudinal guide part parallel to the longitudinal measuring part, the longitudinal measuring part is provided with a fixing assembly, and the longitudinal measuring part is slidably connected to the longitudinal guide part on the fixed part through the fixing assembly; after the positioning step, the longitudinal locking step is included, in which the relative position of the longitudinal measuring part and the second lateral measuring part is fixed by using the fixing assembly.

[0020] Further, the first lateral measuring part is provided with a first lateral guide part, the second lateral measuring part is provided with a second lateral guide part, the first lateral guide part is provided with a first lateral positioning assembly, and the second lateral guide part is provided with a second lateral positioning assembly, the first lateral positioning assembly is used to position the first lateral guide part with the brake pad, and the second lateral positioning assembly is used to position the second lateral guide part with the outer edge of the brake disc; after the longitudinal locking step, the lateral locking step is included, in which the relative position of the friction arc length measuring scale on the brake disc is positioned by using the first lateral positioning assembly and the second lateral positioning assembly.

[0021] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a friction arc length measuring method is provided for measuring and calculating the friction arc length formed by the mutual friction between a brake disc and a brake pad, which includes a measuring scale providing step, a positioning step, a reading step and a calculating step,

[0022] In the measuring scale providing step, a friction arc length measuring scale is provided, the friction arc length measuring scale comprises a first transverse measuring part and a longitudinal measuring part, the first transverse measuring part is used for measuring the chord length of a friction arc of a brake pad at a to-be-measured radius, and the longitudinal measuring part is used for measuring the distance between the first transverse measuring part and the outer edge of a brake disc in a direction perpendicular to the first transverse measuring part, the first transverse measuring part and the longitudinal measuring part each have a scale, the first transverse measuring part has the same center line, the center line is perpendicular to the first transverse measuring part, the scale on the first transverse measuring part is symmetrically distributed relative to the center line, and the longitudinal measuring part is fixed to the first transverse measuring part and arranged along the center line; in the positioning step, a first point on one side of the first transverse measuring part is selected to align with a point on the edge of the brake pad at the to-be-measured radius, the friction arc length measuring scale is rotated, so that the other side of the center line of the first transverse measuring part intersects with the edge of the brake pad to form a fourth point, and the scales at the first point and the fourth point are the same; in the reading step, the scale at the first point and / or the fourth point is read, and the scale of the distance between the first transverse measuring part and the outer edge of the brake disc in the direction perpendicular to the first transverse measuring part measured by the longitudinal measuring part is read; and in the calculating step, the scale read in the reading step and the size of the brake disc are used to calculate the friction arc length.

[0023] The technical scheme of the present application has the following technical effects:

[0024] 1. The friction arc length measuring scale adopts a split design, is divided into an upper scale, a lower scale and a fixing assembly connecting the upper scale and the lower scale, the relative distance between the upper scale and the lower scale can be flexibly adjusted, the measuring scale has good adaptability and a wide application range, and can be applied to the measurement of the friction arc length of brake pads of different radius sizes, different shapes (circular, trapezoidal, triangular or any shape), different thicknesses and different measurement positions (near the shaft center or near the disc edge).

[0025] 2. The relative distance between the upper scale and the lower scale of the friction arc length measuring scale can be adjusted and accurately locked through the fixing assembly, and the first transverse measuring part and the second transverse measuring part also have positioning assemblies that can be locked at fixed positions, and the locking design can ensure that there is no shaking during the measurement, thereby greatly improving the measurement accuracy in actual application.

[0026] 3. The friction arc length measuring scale is designed with standard scales, first and second transverse guide parts and a longitudinal guide part, and the first and second transverse measuring parts are symmetrically designed, which facilitates position adjustment and reading, is simple to operate and has high measurement efficiency.

[0027] 4. The friction arc length measuring method can measure the friction radius of a certain position of a brake pad according to a known to-be-measured point, and can obtain the position of the other end of the friction arc line, so as to measure and calculate the friction arc length between the two points, and the method can still be applied in the absence of a brake pad.

[0028] 5. This method of measuring friction arc length does not require determining the center position of the brake disc. The value of friction arc length can be obtained by accurately measuring the value and substituting it into the formula for accurate calculation, resulting in accurate measurement results. Attached Figure Description

[0029] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 A schematic diagram of a prior art method for measuring friction arc length is shown;

[0031] Figure 2 A schematic diagram of the friction arc length measuring ruler of Embodiment 1 of the present invention is shown;

[0032] Figure 3 A schematic diagram of the friction arc length measurement method of Embodiment 1 of the present invention is shown;

[0033] Figure 4 A schematic diagram of the friction arc length measurement method according to Embodiment 1 of the present invention is shown;

[0034] Figure 5 A schematic diagram of the friction arc length measurement method of Embodiment 2 of the present invention is shown;

[0035] Figure 6 A schematic diagram of the friction arc length measurement method according to Embodiment 2 of the present invention is shown;

[0036] Figure 7 A schematic diagram of the friction arc length measurement method of Embodiment 3 of the present invention is shown;

[0037] Figure 8 A schematic diagram of the friction arc length measurement method according to Embodiment 3 of the present invention is shown;

[0038] The above figures include the following reference numerals:

[0039] 1. Brake disc; 2. Brake pad; 3. First lateral measuring part; 4. Second lateral measuring part; 5. Longitudinal measuring part; 6. Centerline; 7. First position; 8. Second position; 9. Third position; 10. Fourth position; 31. First lateral guide part; 32. First lateral positioning assembly; 41. Second lateral guide part; 42. Second lateral positioning assembly; 43. Fixing part; 51. Fixing assembly; 431. Longitudinal guide part. Detailed Implementation

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] The present invention will be further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention. The term "comprising" indicates the presence of a feature, but does not exclude the presence or addition of one or more other features. The terms "lateral," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In this description, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] Example 1:

[0044] The friction arc length refers to the annular friction band formed on the brake disc surface by the friction between the brake pad and the brake disc. In actual measurement, given a known point A, and another point D on the brake pad located on the same friction radius as point A, the arc length between these two points is... The present invention proposes a tool and method for measuring the length of a circular arc to be measured. By accurately measuring several values ​​and substituting them into a formula for precise calculation, the value of the friction arc length can be obtained.

[0045] According to one aspect of the present invention, a friction arc length measuring ruler is provided, such as... Figures 2-4 As shown, the measuring ruler used to measure the dimensions of the brake pads 2 on the brake disc 1 includes a first lateral measuring section 3, a second lateral measuring section 4, and a longitudinal measuring section 5. These three measuring sections are used to measure separately to obtain three corresponding values. Substituting these three values ​​into a formula, the value of the friction arc length to be measured can be calculated.

[0046] Specifically, the first lateral measuring section 3 and the second lateral measuring section 4 are arranged in parallel, and the longitudinal measuring section 5 is perpendicular to the first lateral measuring section 3 and the second lateral measuring section 4. The first lateral measuring section 3 is used to measure the chord length of the friction arc of the brake pad 2 at the point to be measured, i.e., the arc length. The chord length. The second lateral measuring part 4 is used to measure the chord length of the outer edge of the brake disc 1, and the longitudinal measuring part 5 is used to measure the first distance, which is the distance between the first lateral measuring part 3 and the second lateral measuring part 4.

[0047] Furthermore, standard scales are provided on the first transverse measuring section 3, the second transverse measuring section 4, and the longitudinal measuring section 5 to facilitate reading and improve measurement efficiency. The first transverse measuring section 3 and the longitudinal measuring section 5 are made of transparent material, and the scales include scale lines and scale values. The first transverse measuring section 3 and the second transverse measuring section 4 share the same center line 6, which is perpendicular to both sections. The scales on both sections are symmetrically distributed relative to the center line 6.

[0048] The term "symmetrical distribution" here refers to the fact that both the scale lines and scale values ​​are symmetrically distributed relative to the center line. The scale on the longitudinal measuring section 5 is evenly arranged along and perpendicular to the center line 6. The scale lines on the first transverse measuring section 3 are arranged on the side connected to the longitudinal measuring section 5, evenly distributed along a direction perpendicular to the longitudinal measuring section 5, and perpendicular to the second transverse measuring section 4. This symmetrical distribution of the scale facilitates comparison of the readings on the first transverse measuring section 3 and the second transverse measuring section 4 relative to the center line during measurement, thus making the measurement more convenient and faster.

[0049] This friction arc length measuring ruler can be divided into two parts: an upper ruler and a lower ruler. The upper ruler consists of a longitudinal measuring section 5 and a first transverse measuring section 3; the lower ruler consists of a second transverse measuring section 4 and a fixing section 43. Figure 2 As shown, the longitudinal measuring part 5 is fixed to the first transverse measuring part 3 and is arranged along the center line 6. The second transverse measuring part 4 has a fixing part 43 located on the center line 6. The fixing part 43 is movably connected to the longitudinal measuring part 5, that is, the lower ruler part and the upper ruler part are movably connected. Furthermore, the relative distance between the fixing part 43 and the longitudinal measuring part 5 is adjustable, that is, the relative distance between the upper ruler part and the lower ruler part in the longitudinal direction (i.e., along the direction of the "longitudinal measuring part") and in the axial direction of the brake disc can be flexibly adjusted.

[0050] It should be noted that the "center line" mentioned in this invention refers to the line where the scales of the first transverse measuring part and the second transverse measuring part are symmetrically distributed. It can be a virtual line and is not necessarily an actual structure on the measuring ruler of this invention, nor is it necessarily part or all of the longitudinal measuring part in this embodiment.

[0051] Specifically, the fixing part 43 is arranged parallel to the longitudinal measuring part 5, and the fixing part 43 is provided with a longitudinal guide part 431 parallel to the longitudinal measuring part 5. The longitudinal measuring part 5 is provided with a fixing component 51, and the longitudinal measuring part 5 is slidably connected to the longitudinal guide part 431 on the fixing part 43 through the fixing component 51. The fixing component 51 consists of two or more bolts and multiple nuts that mate with the bolts. Optionally, in other embodiments, other methods can also be used here as the connection method between the fixing part and the longitudinal measuring part, such as pins, tenons, snaps, hooks, etc.

[0052] Preferably, each bolt is fitted with three nuts (upper, middle, and lower) to completely fix the relative position of the longitudinal measuring part 5 and the fixing part 43. Each bolt included in the fixing assembly 51 on the longitudinal measuring part 5 of the upper scale can move flexibly within the groove of the longitudinal guide part 431 in the fixing part 43 of the lower scale. The longitudinal distance between the first and second transverse measuring parts can be flexibly adjusted by the bolts. Moreover, because the bolts have a certain length, the axial distance between the longitudinal measuring part 5 and the fixing part 43 on the brake disc can also be flexibly adjusted by the bolts. After the lower scale part is moved to a certain position, the relative position between the upper and lower scales can be accurately positioned by tightening the three nuts (upper, middle, and lower).

[0053] The friction arc length measuring ruler adopts a split design, consisting of upper and lower rulers and a fixing component connecting the two parts. The relative distance between the upper and lower rulers can be flexibly adjusted, making the measuring ruler highly adaptable and widely applicable. It can be used to measure the friction arc length of brake discs with different radii, brake pads of different shapes (circular, trapezoidal, triangular, etc.), brake pads of different thicknesses, and brake pads of different measurement positions (near the axis, near the disc edge).

[0054] like Figure 2 As shown, the first lateral measuring part 3 has a first lateral guide part 31, and the second lateral measuring part 4 has a second lateral guide part 41. A first lateral positioning component 32 is provided on the first lateral guide part 31; a second lateral positioning component 42 is provided on the second lateral guide part 41. The first lateral positioning component 32 is used to position the first lateral guide part 31 and the brake pad 2, and the second lateral positioning component 42 is used to position the second lateral guide part 41 and the outer edge of the brake disc 1.

[0055] Specifically, both the first lateral positioning component 32 and the second lateral positioning component 42 consist of two or more bolts and corresponding nuts. The two bolts of the first lateral positioning component 32 can move flexibly on the first lateral guide 31 of the first lateral measuring part 3, and the two bolts of the second lateral positioning component 42 can move flexibly on the second lateral guide 41 of the second lateral measuring part 4. Once moved to a predetermined position, the bolts can be locked in place by tightening the corresponding nuts. Optionally, in other embodiments, other methods can be used to connect the first and second lateral positioning components to the first and second lateral guides, such as sliders, threads, gear slides, etc.

[0056] The relative distance between the upper and lower parts of the friction arc length measuring scale can be adjusted and precisely locked by a fixing component. In addition, the first and second transverse measuring parts also have positioning components that can be locked in a fixed position. This locking design ensures that there is no shaking during the measurement process, thereby greatly improving the measurement accuracy in practical applications.

[0057] According to another aspect of the present invention, a method for measuring the friction arc length using the aforementioned friction arc length measuring ruler is proposed, for measuring and calculating the friction arc length of the brake pad 2 on the brake disc 1. The method mainly includes positioning steps, reading steps, and calculation steps, as detailed below:

[0058] Before proceeding with the measurement, the friction arc length measuring ruler described above in this invention is required. The friction arc length measuring ruler mainly comprises two parts: an upper ruler made of a transparent, high-hardness material, and a lower ruler made of stainless steel. Before using this ruler for measurement, the nuts of the bolts on the first and second transverse positioning components, as well as the upper, middle, and lower nuts of the bolts on the fixing components, must be loosened.

[0059] Distance adjustment step

[0060] The distance adjustment step is performed before the positioning step, such as... Figure 2 As shown, in the distance adjustment step, the relative distance between the first lateral measuring part 3 and the second lateral measuring part 4 in the axial direction of the brake disc 1 is adjusted so that the second lateral measuring part 4 is close to the brake disc and the first lateral measuring part 3 is close to the brake pad. At the same time, the first lateral measuring part 3 and the second lateral measuring part 4 remain parallel, so that the friction arc length measuring ruler is adapted to the thickness of the brake pad 2.

[0061] For reference Figure 2The second transverse measuring part 4 has a fixing part 43 located on the center line 6. The fixing part 43 is movably connected to the longitudinal measuring part 5, and the fixing part 43 is provided with a longitudinal guide part 431 parallel to the longitudinal measuring part 5. The longitudinal measuring part 5 is provided with a fixing assembly 51, and the longitudinal measuring part 5 is slidably connected to the longitudinal guide part 431 on the fixing part 43 through the fixing assembly 51. The fixing assembly 51 consists of two or more bolts and multiple nuts that mate with the bolts. Preferably, the fixing assembly 51 consists of two bolts and three nuts (upper, middle, and lower) that mate with each bolt.

[0062] Specifically, adjust the spacing between the upper, middle, and lower nuts of each bolt on the fixing assembly according to the thickness of the brake pads, and then lock the upper and middle nuts of the fixing assembly (note that the lower nut should not be tightened at this time). This will fix the distance between the upper and lower rulers in the axial direction of the wheel disc, and will not affect the adjustment of the distance between the upper and lower rulers in the longitudinal direction in subsequent steps.

[0063] Alternatively, in other embodiments, the distance adjustment step may be omitted.

[0064] Positioning step

[0065] In the positioning step, such as Figure 3 As shown, the known test point at the edge of the brake pad 2 is taken as the first point 7. The edge of the first lateral measuring part 3 with the scale is kept aligned with the first point 7. The friction arc length measuring scale is rotated, and the position of the second lateral measuring part 4 in the radial direction of the brake disc 1 is adjusted. Simultaneously, the distance between the first point 7 and the longitudinal measuring part 5 is adjusted so that the second lateral measuring part 4 intersects with the outer edge of the brake disc 1 to form the second point 8 and the third point 9. At this time, the second point 8 and the third point 9 are aligned with points B and C on the outer edge of the brake disc. Furthermore, the scales on the second point 8 and the third point 9 on the second lateral measuring part 4 are the same. The other side of the center line 6 of the first lateral measuring part 3 intersects with the edge of the brake pad 2 to form the fourth point 10. The corresponding brake pad edge point is... Figure 3 Point D in the middle.

[0066] Specifically, align the first transverse measuring section of the measuring ruler with the point to be measured, A (the point where the friction arc length needs to be measured, not the bolt position). Rotate the measuring ruler circumferentially around point A (the measuring tool and brake pad should always be on the same half-circle of the brake disc) until the readings of the second point 8 and the third point 9 of the second transverse measuring section of the measuring ruler are the same. This ensures that the fourth point 10 and the point to be measured, A, are on the same circumference. At this point, the readings of the first point 7 and the fourth point 10 should also be equal. If they are not equal, the tool has a serious machining error and measurement should not continue.

[0067] At this time, the extension line of the "center line" described in this invention passes through the center of the brake disc.

[0068] Longitudinal locking step

[0069] Following the positioning step, a longitudinal locking step is also included, in which the relative positions of the longitudinal measuring unit 5 and the second transverse measuring unit 4 are fixed using the fixing component 51.

[0070] Specifically, you can refer to Figure 2 First, lock the lower nut of each bolt of the fixing component 51. After locking, continue to fine-tune the measuring ruler with the point to be measured A as the center to ensure that the readings of the second point 8 and the third point 9 are equal, and the readings of the first point 7 and the fourth point 10 are equal.

[0071] Alternatively, in other embodiments, the longitudinal locking step may be omitted.

[0072] Transverse locking step

[0073] Following the longitudinal locking step, a lateral locking step is also included, in which the relative position of the friction arc length measuring ruler on the brake disc 1 is located using the first lateral positioning component 32 and the second lateral positioning component 42.

[0074] For reference Figure 2 The first lateral measuring part 3 has a first lateral guide part 31, and the second lateral measuring part 4 has a second lateral guide part 41. A first lateral positioning component 32 is disposed on the first lateral guide part 31, and a second lateral positioning component 42 is disposed on the second lateral guide part 41. The first lateral positioning component 32 is used to position the first lateral guide part 31 and the brake pad 2, and the second lateral positioning component 42 is used to position the second lateral guide part 41 and the outer edge of the brake disc 1. Preferably, the first lateral positioning component 32 and the second lateral positioning component 42 are two bolts and a nut that mates with them.

[0075] Specifically, such as Figure 3 As shown, the four bolts of the first lateral positioning component 32 and the second lateral positioning component 42 are moved along the first lateral guide 31 and the second lateral guide 41 respectively, so that the threads of the two bolts of the first lateral positioning component 32 are close to the edge of the brake pad, and the threads of the two bolts of the second lateral positioning component 42 are close to the edge of the brake disc. Then the nuts of the four bolts are locked to achieve lateral locking.

[0076] At this point, the other intersection point D between the first transverse measuring part 3 and the edge of the brake pad 2, and the point A to be measured, are two points on the same circumference, and the friction arc length to be measured at the point A is the arc length.

[0077] Alternatively, in other embodiments, the lateral locking step may be omitted.

[0078] Reading step

[0079] In the reading step, look directly at the scale of the measuring ruler and read the scale at the first point 7 and / or the fourth point 10, and record the scale value as a; read the scale at the second point 8 and / or the third point 9, and record the scale value as b; read the scale of the first distance measured by the longitudinal measuring unit 5, and record the scale value as h; the brake disc is a standard part with known and fixed dimensions, and its radius is recorded as R.

[0080] Calculation step

[0081] In the calculation step, the friction arc length is calculated using the scale readings and the dimensions of brake disc 1 obtained in the reading step. Substituting a, b, h, and R into the formula, the friction arc length can be measured.

[0082]

[0083] This method of measuring friction arc length does not require determining the center position of the brake disc. The value of friction arc length can be obtained by accurately measuring the value and substituting it into the formula for accurate calculation, and the measurement result is relatively accurate.

[0084] refer to Figure 4 The derivation of the formula is as follows: arc Let be the arc length to be measured. According to the law of sine, we can obtain:

[0085]

[0086] but:

[0087]

[0088] In triangle AEO, the radian α of ∠AOE is:

[0089]

[0090] arc length required If it is a part of the circumference of the circle it is in, then the arc length is... Possible forms:

[0091]

[0092] Combining the above two equations, we can obtain:

[0093]

[0094] In the above formula, BO is a standard brake disc with known and fixed dimensions, and it is wear-free in the circumferential direction. Its radius is the standard dimension R. The other three parameters in the formula can be measured by the device of the present invention: h is the distance between FE in the figure, a is the distance between AE and ED, and b is the length of BF.

[0095]

[0096] Substituting the measured reading into the above formula yields the friction arc length generated by the brake pad at point A.

[0097] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: 1. The friction arc length measuring ruler adopts a split design, consisting of upper and lower rulers and a fixing component connecting the upper and lower rulers. The relative distance between the upper and lower rulers can be flexibly adjusted, making the measuring ruler adaptable and widely applicable. It can adapt to the measurement of friction arc length of brake discs with different radii, brake pads of different shapes (circular, trapezoidal, triangular, etc.), brake pads of different thicknesses, and different measurement positions (near the axis, near the disc edge); 2. The relative distance between the upper and lower parts of the friction arc length measuring ruler can be adjusted and precisely locked by the fixing component. The first and second transverse measuring parts also have positioning components that can be locked in a fixed position. This locking design ensures that during the measurement process... 1. No shaking occurs during operation, thus greatly improving the measurement accuracy in practical applications; 2. The friction arc length measuring ruler is designed with standard graduations and first and second transverse guides and longitudinal guides. The first and second transverse measuring parts are symmetrically designed, which facilitates position adjustment and reading, making operation simple and measurement efficient; 3. This friction arc length measurement method can measure the friction radius of a certain point on the brake pad based on a known point to be measured, and can obtain the position of the point at the other end of the friction arc, thereby measuring and calculating the friction arc length between the two points. This method can still be applied even without brake pads; 4. This friction arc length measurement method does not require determining the center position of the brake disc. The value of the friction arc length can be obtained by accurately measuring the value and substituting it into the formula for accurate calculation. The measurement result is accurate.

[0098] Example 2:

[0099] The measuring tools and methods used in Example 2 are basically the same as those in Example 1, with the following differences:

[0100] The longitudinal measuring part 5 in the friction arc length measuring ruler used in this embodiment is used to measure the second distance, which can be referred to as... Figure 5The second distance is the distance between the first lateral measuring part 3 and the edge of the brake disc 1 in the direction perpendicular to it. Furthermore, the first lateral measuring part 3, the second lateral measuring part 4, and the longitudinal measuring part 5 are all made of transparent material, that is, the upper and lower rulers of the friction arc length measuring ruler are made of transparent high-hardness material.

[0101] In the friction arc length measurement method used in this embodiment, the friction arc length measuring ruler described above is provided in the first step of the measuring ruler provision step. In the reading step, the scale of the second distance measured by the longitudinal measuring unit 5 is read, and this scale value is recorded as h. In the calculation step, a, b, h, and R are substituted into another formula for calculation using the scale read in the reading step and the size of the brake disc 1. The derivation process of this formula can be referred to as follows: Figure 6 The specific measurement principle diagram shown is illustrated below. In the diagram, h represents the length of GE, a remains the distance between AE and ED, b remains the length of BF, and R remains the radius of the brake disc. Those skilled in the art can obtain the following through calculation: The arc length of the arc.

[0102] From the above description, it can be seen that Embodiment 2 of the present invention achieves the following technical effects: 1. The friction arc length measuring ruler adopts a split design, consisting of upper and lower rulers and a fixing component connecting the upper and lower rulers. The relative distance between the upper and lower rulers can be flexibly adjusted, making the measuring ruler adaptable and widely applicable. It can adapt to the measurement of friction arc length of brake discs with different radii, brake pads of different shapes (circular, trapezoidal, triangular, etc.), brake pads of different thicknesses, and different measurement positions (near the axis, near the disc edge); 2. The relative distance between the upper and lower parts of the friction arc length measuring ruler can be adjusted and precisely locked by the fixing component. The first and second transverse measuring parts also have positioning components that can be locked in a fixed position. This locking design ensures that during the measurement process... 1. No shaking occurs during operation, thus greatly improving the measurement accuracy in practical applications; 2. The friction arc length measuring ruler is designed with standard graduations and first and second transverse guides and longitudinal guides. The first and second transverse measuring parts are symmetrically designed, which facilitates position adjustment and reading, making operation simple and measurement efficiency high; 3. This friction arc length measurement method can measure the friction radius of a certain point on the brake pad based on a known point to be measured, and can obtain the position of the point at the other end of the friction arc, thereby measuring and calculating the friction arc length between the two points. This method can still be applied even without brake pads; 4. This friction arc length measurement method does not require determining the center position of the brake disc. The value of the friction arc length can be obtained by accurately measuring the value and substituting it into the formula for accurate calculation. The measurement result is relatively accurate.

[0103] Example 3:

[0104] According to another aspect of the present invention, a method for measuring the friction arc length is proposed for measuring and calculating the friction arc length of the brake pad 2 on the brake disc 1, including a measuring ruler provision step, a positioning step, a reading step, and a calculation step.

[0105] like Figure 7 As shown, in the step of providing a measuring ruler, a friction arc length measuring ruler is provided. This friction arc length measuring ruler includes a first transverse measuring part 3 and a longitudinal measuring part 5. Both the first transverse measuring part 3 and the longitudinal measuring part 5 are made of transparent material. The first transverse measuring part 3 is used to measure the chord length of the friction arc of the brake pad 2 at the radius to be measured. The longitudinal measuring part 5 is used to measure the distance between the first transverse measuring part 3 and the outer edge of the brake disc 1 along a direction perpendicular to the first transverse measuring part 3. Both the first transverse measuring part 3 and the longitudinal measuring part 5 have scales. The first transverse measuring part 3 has a center line 6. The center line 6 is perpendicular to the first transverse measuring part 3 and is symmetrically distributed relative to the center line 6. The longitudinal measuring part 5 is fixed to the first transverse measuring part 3 and is set along the center line 6.

[0106] In the positioning step, the first point 7 on one side of the first transverse measuring part 3 is selected and aligned with point A on the edge of the brake pad 2 on the radius to be measured. The friction arc length measuring ruler is rotated so that the other side of the center line 6 of the first transverse measuring part 3 intersects with the edge of the brake pad 2 to form a fourth point 10, which corresponds to point D on the edge of the brake pad. The scales on the first point 7 and the fourth point 10 are the same.

[0107] In the reading step, the scale of the first point 7 and / or the fourth point 10 is read and recorded as a and d respectively. The scale of the distance between the first transverse measuring part 3 and the outer edge of the brake disc 1 in the direction perpendicular to the first transverse measuring part 3, as measured by the longitudinal measuring part 5, is read and recorded as h.

[0108] In the calculation step, the friction arc length is calculated using the scale readings and the dimensions of brake disc 1 obtained in the reading step.

[0109] The specific measurement principle is as follows: Figure 8 As shown, h is the distance from point G to the midpoint of chord AD in the diagram. The radius of the brake disc is known as R, which can be calculated by those skilled in the art. The arc length of the arc.

[0110] From the above description, it can be seen that Embodiment 3 of the present invention achieves the following technical effects: 1. The tool structure is simpler than that of the previous embodiments, the measurement and calculation are more convenient, and the operation is more convenient. 2. This friction arc length measurement method can measure the friction radius of a certain point on the brake pad based on a known point to be measured, and can obtain the position of the point at the other end of the friction arc, thereby measuring and calculating the friction arc length between the two points. This method can still be applied even without a brake pad.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A friction arc length measuring ruler, used to measure the length of the friction arc formed by the mutual friction between a brake disc (1) and a brake pad (2), characterized in that, It includes a first transverse measuring section (3), a second transverse measuring section (4), and a longitudinal measuring section (5). The first transverse measuring section (3) and the second transverse measuring section (4) are arranged in parallel, and the longitudinal measuring section (5) is perpendicular to the first transverse measuring section (3) and the second transverse measuring section (4). The first transverse measuring section (3), the second transverse measuring section (4), and the longitudinal measuring section (5) all have scales. The first transverse measuring section (3) and the second transverse measuring section (4) have the same center line (6). The center line (6) is perpendicular to the first transverse measuring section (3) and the second transverse measuring section (4). The scales on the first transverse measuring section (3) and the second transverse measuring section (4) are symmetrically distributed relative to the center line (6). The longitudinal measuring part (5) is fixed to the first transverse measuring part (3) and is arranged along the center line (6). The second transverse measuring part (4) has a fixing part (43) located on the center line (6). The fixing part (43) is movably connected to the longitudinal measuring part (5), and the relative distance between the fixing part (43) and the longitudinal measuring part (5) is adjustable. The first lateral measuring part (3) has a first lateral guide part (31), and the second lateral measuring part (4) has a second lateral guide part (41). A first lateral positioning component (32) is provided on the first lateral guide part (31), and a second lateral positioning component (42) is provided on the second lateral guide part (41). The first lateral positioning component (32) is used to position the first lateral guide part (31) and the brake pad (2), and the second lateral positioning component (42) is used to position the second lateral guide part (41) and the outer edge of the brake disc (1). The first lateral measuring part is used to measure the chord length of the friction arc of the brake pad (2) at the point to be measured; the second lateral measuring part (4) is used to measure the chord length of the outer edge of the brake disc (1); and the longitudinal measuring part (5) is used to measure the first distance and / or the second distance. The first distance is the distance between the first lateral measuring part (3) and the second lateral measuring part (4); The second distance is the distance between the first lateral measuring part (3) and the edge of the brake disc (1) in the direction perpendicular to it.

2. The friction arc length measuring ruler according to claim 1, characterized in that, The fixing part (43) is arranged parallel to the longitudinal measuring part (5), and the fixing part (43) is provided with a longitudinal guide part (431) parallel to the longitudinal measuring part (5). The longitudinal measuring part (5) is provided with a fixing component (51), and the longitudinal measuring part (5) is slidably connected to the longitudinal guide part (431) on the fixing part (43) through the fixing component (51).

3. The friction arc length measuring ruler according to claim 2, characterized in that, The fixing component (51) consists of two or more bolts and a plurality of nuts that mate with the bolts.

4. The friction arc length measuring ruler according to any one of claims 1-3, characterized in that, One or more of the longitudinal measuring part (5), the fixing part (43), the first transverse measuring part (3), and the second transverse measuring part (4) are made of transparent material, and the scale includes scale lines and scale values.

5. The friction arc length measuring ruler according to any one of claims 1-3, characterized in that, The first lateral positioning component (32) and the second lateral positioning component (42) each consist of two or more bolts and nuts that mate with them.

6. A method for measuring the friction arc length using the friction arc length measuring ruler according to any one of claims 1-5, for measuring and calculating the friction arc length of the brake pads (2) on the brake disc (1), characterized in that, It includes positioning steps, reading steps, and calculation steps. In the positioning step, the test point at the edge of the known brake pad (2) is taken as the first point (7). The edge of the first lateral measuring part (3) with the scale is kept to coincide with the first point (7). The friction arc length measuring ruler is rotated and / or the position of the second lateral measuring part (4) in the radial direction of the brake disc (1) is adjusted and / or the distance between the first point (7) and the longitudinal measuring part (5) is adjusted so that the second lateral measuring part (4) intersects with the outer edge of the brake disc (1) to form the second point (8) and the third point (9), and the scales on the second point (8) and the third point (9) are the same. The first lateral measuring part (3) intersects with the edge of the brake pad (2) to form the fourth point (10). In the reading step, the scale of the first point (7) and / or the fourth point (10) is read, the scale of the second point (8) and / or the third point (9) is read, and the scale of the first distance or the second distance measured by the longitudinal measuring unit (5) is read. In the calculation step, the friction arc length is calculated using the scale readings from the reading step and the dimensions of the brake disc (1).

7. The method for measuring the friction arc length according to claim 6, characterized in that, It also includes a distance adjustment step, which is performed before the positioning step. In the distance adjustment step, the relative distance between the first lateral measuring part (3) and the second lateral measuring part (4) in the axial direction of the brake disc (1) is adjusted so that the second lateral measuring part (4) is close to the brake disc and the first lateral measuring part (3) is close to the brake pad. At the same time, the first lateral measuring part (3) and the second lateral measuring part (4) remain parallel to each other so that the friction arc length measuring ruler is adapted to the thickness of the brake pad (2).

8. The method for measuring the friction arc length according to claim 7, characterized in that, The second transverse measuring part (4) has a fixing part (43) located on the center line (6). The fixing part (43) is movably connected to the longitudinal measuring part (5). The fixing part (43) is provided with a longitudinal guide part (431) parallel to the longitudinal measuring part (5). The longitudinal measuring part (5) is provided with a fixing component (51). The longitudinal measuring part (5) is slidably connected to the longitudinal guide part (431) on the fixing part (43) through the fixing component (51). Following the positioning step, a longitudinal locking step is included, in which the relative positions of the longitudinal measuring part (5) and the second transverse measuring part (4) are fixed using the fixing component (51).

9. The method for measuring the friction arc length according to claim 8, characterized in that, The first lateral measuring part (3) has a first lateral guide part (31), and the second lateral measuring part (4) has a second lateral guide part (41). A first lateral positioning component (32) is provided on the first lateral guide part (31), and a second lateral positioning component (42) is provided on the second lateral guide part (41). The first lateral positioning component (32) is used to position the first lateral guide part (31) and the brake pad (2), and the second lateral positioning component (42) is used to position the second lateral guide part (41) and the outer edge of the brake disc (1). Following the longitudinal locking step, a lateral locking step is included, in which the relative position of the friction arc length measuring scale on the brake disc (1) is positioned using the first lateral positioning component (32) and the second lateral positioning component (42).

10. A method for measuring the length of a friction arc, used to measure and calculate the length of the friction arc formed by the mutual friction between a brake disc (1) and a brake pad (2), characterized in that, This includes the steps for providing the measuring ruler, positioning, reading, and calculation. In the step of providing the measuring ruler, a friction arc length measuring ruler is provided. The friction arc length measuring ruler includes a first transverse measuring part (3) and a longitudinal measuring part (5). The first transverse measuring part (3) is used to measure the chord length of the friction arc of the brake pad (2) at the radius to be measured. The longitudinal measuring part (5) is used to measure the distance between the first transverse measuring part (3) and the outer edge of the brake disc (1) along a direction perpendicular to the first transverse measuring part (3). Both the first transverse measuring part (3) and the longitudinal measuring part (5) have scales. The first transverse measuring part (3) has a center line (6). The center line (6) is perpendicular to the first transverse measuring part (3) and relative to the center line (6). The scales on the first transverse measuring part (3) are symmetrically distributed. The longitudinal measuring part (5) is fixed to the first transverse measuring part (3) and is set along the center line (6). In the positioning step, the first point (7) on one side of the first transverse measuring part (3) is selected and aligned with the point on the edge of the brake pad (2) on the radius to be measured. The friction arc length measuring ruler is rotated so that the other side of the center line (6) of the first transverse measuring part (3) intersects with the edge of the brake pad (2) to form a fourth point (10), and the scale readings on the first point (7) and the fourth point (10) are the same. In the reading step, the scale of the first point (7) and / or the fourth point (10) is read, and the scale of the distance between the first transverse measuring part (3) and the outer edge of the brake disc (1) in the direction perpendicular to the first transverse measuring part (3) is read by the longitudinal measuring part (5). In the calculation step, the friction arc length is calculated using the scale readings from the reading step and the dimensions of the brake disc (1).

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