Threaded raceway pitch diameter measuring tool for ball screw nut

Abstract

The invention discloses a measuring tool for the pitch diameter of a threaded raceway of a ball screw nut, a mounting base structure comprises a moving block and a measuring frame, and the moving block is slidably mounted in the measuring frame; the moving assembly comprises a first sliding rod, a first sliding sleeve, a second sliding rod and a second sliding sleeve, the first sliding rod is vertically installed in the measuring frame and penetrates through the moving block, the first sliding sleeve slidably sleeves the first sliding rod and is connected with the moving block, and the second sliding rod is vertically installed in the measuring frame and fixedly penetrates through the moving block; the second sliding sleeve sleeves the lower end of the second sliding rod and is connected with the bottom of the measuring frame, the measuring head assembly comprises a first measuring head, a second measuring head and an elastic piece, the first measuring head and the second measuring head are symmetrically arranged, the first measuring head is installed on the moving block, the second measuring head is installed on the measuring frame, and the elastic piece is clamped between the first measuring head and the second measuring head; and a measuring rod of the dial indicator extends into the measuring frame and is coaxially arranged with the second sliding rod.

Description

Technical Field

[0001] This invention relates to the field of ball screw measurement technology, and more specifically to a measuring tool for the mean diameter of the thread raceway of a ball screw nut. Background Technology

[0002] Ball screw assemblies are key components in precision transmission, completely replacing the sliding friction of traditional sliding screws with rolling friction. They are widely used in automation and precision equipment. The mean diameter of the thread raceway affects the assembly clearance and preload of the ball screw, which directly impact the final accuracy of the ball screw and are therefore extremely important. To ensure the accuracy of ball screw assemblies, measuring tools are often used to measure them.

[0003] The commonly used measurement methods currently have the following problems: 1. Steel ball measurement method: The measurement process is cumbersome, inefficient, and requires complex calculations to obtain the measurement results. It also places high demands on operators and is prone to calculation errors, leading to batch defects in products. 2. Measurement with general measuring tools (such as a modified 5-inch internal micrometer): The upper and lower probes are glued or welded with steel balls. This method is prone to skew, resulting in inaccurate measurement positioning, poor measurement repeatability, and inability to guarantee accuracy. 3. Large precision instruments (such as coordinate measuring machines): These are expensive, have demanding environmental requirements, and long testing cycles, making them unsuitable for rapid on-site inspection.

[0004] Therefore, there is an urgent need to design a new tool for measuring the mean diameter of the thread raceway of ball screw nuts to overcome the above-mentioned defects. Summary of the Invention

[0005] The purpose of this invention is to provide a measuring tool for the pitch diameter of the thread raceway of a ball screw nut. This measuring tool has a compact and convenient structure, high measurement accuracy, simple operation, high positioning accuracy, and fast testing efficiency. Its manufacturing and maintenance costs are far lower than those of large precision measuring instruments, making it easy to popularize and apply. By changing the probe of different sizes or adjusting the positioning components, it can be adapted to the measurement needs of ball screw pairs of different specifications.

[0006] To achieve the above objectives, the present invention provides a measuring tool for the mean diameter of the thread raceway of a ball screw nut, comprising: a mounting base structure, wherein the mounting base structure includes a movable block and a measuring frame, and the movable block is slidably mounted within the measuring frame;

[0007] A movable component includes a first slide rod, a first sliding sleeve, a second slide rod, and a second sliding sleeve. The first slide rod is vertically installed inside the measuring frame and passes through a movable block. The first sliding sleeve is slidably fitted onto the first slide rod and connected to the movable block. The second slide rod is vertically installed inside the measuring frame and fixedly inserted into the movable block. The second sliding sleeve is fitted onto the lower end of the second slide rod and connected to the bottom of the measuring frame. The length of the second slide rod is shorter than the length of the first slide rod.

[0008] A probe assembly, comprising a first probe, a second probe, and an elastic element, wherein the first probe and the second probe are symmetrically arranged, the first probe is mounted on a movable block, the second probe is mounted on a measuring frame, and the elastic element is clamped between the first probe and the second probe.

[0009] A dial indicator, wherein the measuring rod of the dial indicator extends into the measuring frame and is coaxially arranged with the second slide rod.

[0010] Preferably, a movable handle extending to the outside of the measuring frame is mounted on the movable block, and a fixed handle extending to the outside of the measuring frame is fixedly mounted on the second sliding sleeve.

[0011] Preferably, the first probe includes a first mounting part, a first support part, and a first arc plate. The first mounting part is connected to the moving block, the first support part is connected to one side of the first mounting part, the first arc plate is mounted on the upper surface of the first support part, and a first flange is formed on the first arc plate.

[0012] Preferably, the second probe includes a second mounting part, a second support part, and a second arc-shaped plate. A fixing block is fixedly installed at the bottom of the measuring frame. The second sliding part is installed inside the fixing block. The second mounting part is connected to the fixing block. The second support part is connected to one side of the second mounting part. The second arc-shaped plate is installed on the lower surface of the second support part, and a second flange is formed on the second arc-shaped plate.

[0013] Preferably, the first arc-shaped plate has a first placement hole along the first flange, and a first steel ball is placed in the first placement hole; the second arc-shaped plate has a second placement hole along the second flange, and a second steel ball is placed in the second placement hole.

[0014] Preferably, the first support portion has a first screw hole and a first mounting groove, and the first arc-shaped plate has an upper screw hole and an upper mounting hole. The first arc-shaped plate is mounted on the first support portion by passing a screw through the first screw hole and the upper screw hole, and by passing a positioning pin through the upper mounting hole and the first mounting groove. The second support portion has a second screw hole and a second mounting groove, and the second arc-shaped plate has a lower screw hole and a lower mounting hole. The second arc-shaped plate is mounted on the first support portion by passing a screw through the second screw hole and the lower screw hole, and by passing a positioning pin through the lower mounting hole and the second mounting groove.

[0015] Preferably, it also includes a fixing sleeve, which is installed on the measuring frame, and the measuring rod of the dial indicator is inserted into the fixing sleeve.

[0016] Compared with existing technologies, the advantages are: 1) The measuring tool has a compact and convenient structure, high measurement accuracy, simple operation, high positioning accuracy, and fast detection efficiency; the manufacturing and maintenance costs are far lower than those of large precision measuring instruments, making it easy to popularize and apply; by replacing probes of different sizes or adjusting positioning components, it can be adapted to the measurement needs of ball screw pairs of different specifications. 2) A rounded chamfer is formed at the first and second placement holes. The designed rounded chamfer constitutes an anti-drop structure, which can eliminate the risk of steel balls falling off due to oil stains. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional view of a gauge for measuring the mean diameter of the thread raceway of a ball screw nut.

[0019] Figure 2 A three-dimensional view of the mean diameter gauge of the thread raceway of a ball screw nut from another perspective.

[0020] Figure 3 This is a cross-sectional view of a gauge for measuring the mean diameter of the thread raceway of a ball screw nut.

[0021] Figure 4 This is a partial structural diagram of a gauge for measuring the mean diameter of the thread raceway of a ball screw nut.

[0022] Figure 5 This is an exploded view of the probe assembly.

[0023] Reference numerals: 1. Moving block; 2. Measuring frame; 21. Fixed block; 3. Moving assembly; 31. First slide rod; 32. First sliding sleeve; 33. Second slide rod; 34. Second sliding sleeve; 4. Probe assembly; 41. First probe; 411. First mounting part; 412. First support part; 4121. First screw hole; 4122. First mounting groove; 413. First arc-shaped plate; 4131. Upper screw hole; 4132. Upper mounting hole; 414. First flange; 415. First placement hole; 4 16. First steel ball; 42. Second probe; 421. Second mounting part; 422. Second support part; 4221. Second screw hole; 4222. Second mounting groove; 423. Second arc plate; 4231. Lower screw hole; 4232. Lower mounting hole; 424. Second flange; 425. Second placement hole; 426. Second steel ball; 43. Elastic element; 5. Dial indicator; 51. Measuring rod; 6. Fixed handle; 7. Moving handle; 8. Fixed sleeve; 9. Inner diameter ring gauge; 10. Ball screw nut. Detailed Implementation

[0024] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are merely for explaining the invention and are not intended to limit the invention.

[0025] It should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the 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. Therefore, they should not be construed as limitations on the present invention.

[0026] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Additionally, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0028] Please see Figures 1 to 5 The present invention provides a measuring tool for measuring the mean diameter of the thread raceway of a ball screw nut, comprising: a mounting base structure, wherein the mounting base structure includes a movable block 1 and a measuring frame 2, wherein the movable block 1 is slidably mounted in the measuring frame 2;

[0029] The moving component 3 includes a first slide rod 31, a first sliding sleeve 32, a second slide rod 33, and a second sliding sleeve 34. The first slide rod 31 is vertically installed inside the measuring frame 2 and passes through the moving block 1. The first sliding sleeve 32 is slidably fitted onto the first slide rod 31 and fixedly connected to the moving block 1. The second slide rod 33 is vertically installed inside the measuring frame 2 and fixedly inserted into the moving block 1. The second sliding sleeve 34 is fitted onto the lower end of the second slide rod 33 and fixedly connected to the bottom of the measuring frame 2. The length of the second slide rod 33 is shorter than the length of the first slide rod 31.

[0030] The probe assembly 4 includes a first probe 41, a second probe 42, and an elastic element 43. The first probe 41 and the second probe 42 are symmetrically arranged, and the first probe 41 is mounted on the moving block 1. The second probe 42 is fixedly mounted on the measuring frame 2. The elastic element 43 is sandwiched between the first probe 41 and the second probe 42.

[0031] The dial indicator 5 has a measuring rod 51 that extends into the measuring frame 2 and is coaxially arranged with the second slide rod 33. A moving handle 7 extending to the outside of the measuring frame 2 is mounted on the moving block 1, and a fixed handle 6 extending to the outside of the measuring frame 2 is fixedly mounted on the second slide sleeve 34. It should be noted that in this embodiment, the elastic element 43 is a spring.

[0032] Thus, pulling down the moving handle 7 causes the moving block 1 to move the first probe 41 downwards, compressing the elastic element 43 between the first probe 41 and the second probe 42. An inner diameter ring gauge 9, with the same specifications as the ball screw nut 8, is fitted onto the first probe 41 and the second probe 42 of the probe assembly 4. After releasing the moving handle 7, the elastic element 43 pushes the moving block 1 upwards, making the outer surfaces of the first and second probes 42 in close contact with the inner wall of the inner diameter ring gauge 9. At the same time, the moving block 1 drives the upper end of the second slide rod 33 to abut against the measuring rod 51 of the dial indicator 5. The dial indicator 5 displays the measurement data, and at this time, the inner diameter ring gauge 9 is the default standard reference component.

[0033] Remove the inner diameter ring gauge 9, and pull down the moving handle 7 again to make the moving block 1 drive the first probe 41 to move downward, so that the elastic element 43 between the first probe 41 and the second probe 42 is compressed, and the second slide rod 33 is inserted into the bottom of the second sliding sleeve 34 as the moving block 1 moves downward. That is, the more the moving block 1 moves downward, the deeper the second slide rod 33 is inserted into the second sliding sleeve 34.

[0034] The ball screw nut 8 is fitted onto the first probe 41 and the second probe 42 of the probe assembly 4. After releasing the moving handle 7, the elastic element 43 pushes the moving block 1 upward, causing the outer surfaces of the first and second probes 42 to make close contact with the inner wall of the inner diameter ring gauge 9. At the same time, the moving block 1 drives the upper end of the second slide rod 33 to abut against the measuring rod 51 of the dial indicator 5. If the measurement data of the dial indicator 5 is consistent with the measurement data when measuring the inner diameter ring gauge 9, it indicates that the ball screw nut 8 is a qualified product. This measuring tool has a compact and convenient structure, high measurement accuracy, and fast testing efficiency.

[0035] In one specific embodiment, the first probe 41 includes a first mounting portion 411, a first support portion 412, and a first arc-shaped plate 413. The first mounting portion 411 is connected to the moving block 1, the first support portion 412 is connected to one side of the first mounting portion 411, and the first arc-shaped plate 413 is mounted on the upper surface of the first support portion 412, with an arc-shaped first flange 414 protruding from the first arc-shaped plate 413. Thus, when the moving block 1 moves up and down, it can drive the first probe 41 to move up and down, allowing the first probe 41 to be finely adjusted in the vertical direction, avoiding rigid contact between the probe assembly 4 and the inner diameter ring gauge 9 or the inner wall of the ball screw nut 8 being measured.

[0036] In one specific embodiment, the second probe 42 includes a second mounting part 421, a second support part 422, and a second arc-shaped plate 423. A fixing block 21 is fixedly mounted on the bottom of the measuring frame 2. The second sliding sleeve 34 is installed inside the fixing block 21. The second mounting part 421 is connected to the fixing block 21. The second support part 422 is connected to one side of the second mounting part 421. The second arc-shaped plate 423 is installed on the lower surface of the second support part 422, and an arc-shaped second flange 424 is formed on the second arc-shaped plate 423.

[0037] It should be noted that both the first support portion 412 and the second support portion 422 are semi-cylindrical, and the support portions 412 and 422 are symmetrically distributed vertically. When the first support portion 412 and the second support portion 422 are fitted together, they can form a cylindrical shape. Furthermore, the shapes of the first flange 414 and the second flange 424 correspond to the grooves inside the ball screw nut 8 being tested.

[0038] In one specific embodiment, the first arc plate 413 has a first placement hole 415 along the first flange 414, and a first steel ball 416 is placed in the first placement hole 415. The second arc plate 423 has a second placement hole 425 along the second flange 424, and a second steel ball 426 is placed in the second placement hole 425.

[0039] It should be noted that the first flange 414 has a rounded chamfer at the first placement hole 415, and the second flange 424 has a rounded chamfer at the second placement hole 425. The designed rounded chamfers form an anti-drop structure to prevent the steel ball from falling. The outer curvature of the first flange 414 and the second flange 424 are matched with the inner curvature of the raceway on the inner wall of the ball screw nut 8 being tested. The steel ball has the same volume as the steel ball assembled in the ball screw pair.

[0040] During installation, the first steel ball 416 is placed above the first support 412, and the first arc plate 413 is installed on the upper surface of the first support 412, with the first steel ball 416 being secured in the first placement hole 415; the second steel ball 426 is placed above the second support 422, and the second arc plate 423 is installed on the lower surface of the second support 422, with the second steel ball 426 being secured in the second placement hole 425. The designed rounded chamfers form an anti-drop structure, which can prevent the steel ball from falling.

[0041] In one specific embodiment, the first support portion 412 is provided with a first screw hole 4121 and a first mounting groove 4122, and the first arc-shaped plate 413 is provided with an upper screw hole 4131 and an upper mounting hole 4132. The first arc-shaped plate 413 is fixedly mounted on the first support portion 412 by passing a screw through the first screw hole 4121 and the upper screw hole 4131, and by passing a positioning pin through the upper mounting hole 4132 and the first mounting groove 4122. The second support portion 422 is provided with a second screw hole 4221 and a second mounting groove, and the second arc-shaped plate 423 is provided with a lower screw hole 4231 and a lower mounting hole 4232. The second arc-shaped plate 423 is fixedly mounted on the first support portion 412 by passing a screw through the second screw hole 4221 and the lower screw hole 4231, and by passing a positioning pin through the lower mounting hole 4232 and the second mounting groove.

[0042] This increases the installation stability of the first arc-shaped plate 413 and the second arc-shaped plate 423, preventing them from becoming loose. Furthermore, during installation, the upper surface of the first support portion 412 is completely in contact with the lower surface of the first arc-shaped plate 413, and the lower surface of the second support portion 422 is completely in contact with the upper surface of the second arc-shaped plate 423.

[0043] In one specific embodiment, the measuring tool for the mean diameter of the thread raceway of the ball screw nut further includes a fixing sleeve 8, which is fixedly installed on the top surface of the measuring frame 2. The measuring rod 51 of the dial indicator 5 is inserted into the fixing sleeve 8. This ensures the linear movement of the measuring rod 51, eliminates lateral forces, and facilitates installation.

[0044] In use, pulling down the moving handle 7 causes the moving block 1 to move the first probe 41 downwards, compressing the elastic element 43 between the first probe 41 and the second probe 42. An inner diameter ring gauge 9, with the same specifications as the ball screw nut 8, is fitted onto the first probe 41 and the second probe 42 of the probe assembly 4. After releasing the moving handle 7, the elastic element 43 pushes the moving block 1 upwards, making the outer surfaces of the first and second probes 42 in close contact with the inner wall of the inner diameter ring gauge 9. At the same time, the moving block 1 drives the upper end of the second slide rod 33 to abut against the measuring rod 51 of the dial indicator 5. The dial indicator 5 displays the measurement data. At this time, the inner diameter ring gauge 9 is the default standard reference component.

[0045] Remove the inner diameter ring gauge 9, and pull down the moving handle 7 again to make the moving block 1 drive the first probe 41 to move downward, so that the elastic element 43 between the first probe 41 and the second probe 42 is compressed, and the second slide rod 33 is inserted into the bottom of the second sliding sleeve 34 as the moving block 1 moves downward. That is, the more the moving block 1 moves downward, the deeper the second slide rod 33 is inserted into the second sliding sleeve 34.

[0046] When the ball screw nut 8 is placed on the first probe 41 and the second probe 42 of the probe assembly 4, and the moving handle 7 is released, the elastic element 43 will push the moving block 1 upward, so that the outer surface of the first probe and the second probe 42 is in close contact with the inner wall of the inner diameter ring gauge 9. At the same time, the moving block 1 drives the upper end of the second slide rod 33 to abut against the measuring rod 51 of the dial indicator 5. If the measurement data of the dial indicator 5 is consistent with the measurement data when measuring the inner diameter ring gauge 9, it indicates that the ball screw nut 8 is a qualified product.

[0047] The measuring instrument in this invention features a compact and convenient design, high measurement accuracy, simple operation, high positioning accuracy, and fast testing efficiency. Its simple structure means that manufacturing and maintenance costs are far lower than those of large precision measuring instruments, facilitating widespread application. It has a wide range of applications: by changing different sized probes or adjusting positioning components, it can be adapted to the measurement needs of different specifications of ball screw assemblies.

[0048] Furthermore, due to prolonged use, steel balls can become soaked in oil, which can cause them to fall off or become misaligned over time, making it difficult to detect and posing a significant risk to the accuracy of dimensional inspection. This technical solution involves creating a first placement hole 415 and a second placement hole 425 on the first flange 414 of the first arc-shaped plate 413 and the second flange 424 of the second arc-shaped plate 423, respectively. Rounded chamfers are formed at the first and second placement holes 415 and 425, creating an anti-fall-off structure. After the steel ball is placed inside, the first and second arc-shaped plates 413 and 423 are inserted and secured. This structural design eliminates the risk of steel balls falling off due to oil soaking.

[0049] The present invention is not limited to the description in the specification and embodiments, and thus other advantages and modifications can be readily realized by those skilled in the art. Therefore, the present invention is not limited to the specific details, representative devices and examples shown and described herein without departing from the spirit and scope of the general concept as defined by the claims and their equivalents.

Claims

1. A gauge for the pitch diameter of the thread raceway of a ball screw nut, characterized in that, include: The mounting base structure includes a movable block (1) and a measuring frame (2), wherein the movable block (1) is slidably mounted within the measuring frame (2); The moving component (3) includes a first slide rod (31), a first sliding sleeve (32), a second slide rod (33), and a second sliding sleeve (34). The first slide rod (31) is vertically installed inside the measuring frame (2) and passes through the moving block (1). The first sliding sleeve (32) is slidably fitted on the first slide rod (31) and connected to the moving block (1). The second slide rod (33) is vertically installed inside the measuring frame (2) and fixedly inserted into the moving block (1). The second sliding sleeve (34) is fitted on the lower end of the second slide rod (33) and connected to the bottom of the measuring frame (2). The length of the second slide rod (33) is shorter than the length of the first slide rod (31). The probe assembly (4) includes a first probe (41), a second probe (42), and an elastic element (43). The first probe (41) and the second probe (42) are symmetrically arranged, and the first probe (41) is mounted on the moving block (1), the second probe (42) is mounted on the measuring frame (2), and the elastic element (43) is sandwiched between the first probe (41) and the second probe (42). A dial indicator (5) has a measuring rod (51) that extends into the measuring frame (2) and is coaxially arranged with the second slide rod (33).

2. The thread raceway pitch diameter measuring tool for ball screw nuts as described in claim 1, characterized in that, A movable handle (7) extending to the outside of the measuring frame (2) is installed on the movable block (1), and a fixed handle (6) extending to the outside of the measuring frame (2) is fixedly installed on the second sliding sleeve (34).

3. The measuring tool for the mean diameter of the thread raceway of a ball screw nut as described in claim 1, characterized in that, The first probe (41) includes a first mounting part (411), a first support part (412) and a first arc plate (413). The first mounting part (411) is connected to the moving block (1). The first support part (412) is connected to one side of the first mounting part (411). The first arc plate (413) is mounted on the upper surface of the first support part (412), and a first flange (414) is formed on the first arc plate (413).

4. The thread raceway pitch diameter measuring tool for ball screw nuts as described in claim 3, characterized in that, The second probe (42) includes a second mounting part (421), a second support part (422), and a second arc plate (423). A fixing block (21) is fixedly installed at the bottom of the measuring frame (2). The second sliding sleeve (34) is installed inside the fixing block (21). The second mounting part (421) is connected to the fixing block (21). The second support part (422) is connected to one side of the second mounting part (421). The second arc plate (423) is installed on the lower surface of the second support part (422), and a second flange (424) is formed on the second arc plate (423).

5. The thread raceway pitch diameter measuring tool for ball screw nuts as described in claim 3, characterized in that, The first arc plate (413) has a first placement hole (415) along the first flange (414), and a first steel ball (416) is placed in the first placement hole (415). The second arc plate (423) has a second placement hole (425) along the second flange (424), and a second steel ball (426) is placed in the second placement hole (425).

6. The thread raceway pitch diameter measuring tool for ball screw nuts as described in claim 3, characterized in that, The first support portion (412) is provided with a first screw hole (4121) and a first mounting groove (4122), and the first arc-shaped plate (413) is provided with an upper screw hole (4131) and an upper mounting hole (4132). A screw passes through the first screw hole (4121) and the upper screw hole (4131), and a locating pin passes through the upper mounting hole (4132) and the first mounting groove (4122) to mount the first arc-shaped plate (413) onto the first support portion. On the second support (422), a second screw hole (4221) and a second mounting groove are provided. The second arc plate (423) is provided with a lower screw hole (4231) and a lower mounting hole (4232). A screw passes through the second screw hole (4221) and the lower screw hole (4231), and a positioning pin passes through the lower mounting hole (4232) and the second mounting groove. The second arc plate (423) is then installed on the first support (412).

7. The thread raceway pitch diameter measuring tool for ball screw nuts as described in claim 1, characterized in that, It also includes a fixing sleeve (8), which is installed on the measuring frame (2), and the measuring rod (51) of the dial indicator (5) is inserted into the fixing sleeve (8).

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