Lead screw roundness measuring device

Abstract

The invention provides a lead screw roundness measuring device, and belongs to the technical field of machinery. The problem that a measuring rod of a dial indicator easily falls into a screw thread groove in the existing screw roundness measuring process is solved. The lead screw roundness measuring device comprises a workbench, two bases, a support and a measuring instrument, V-shaped openings are formed in the tops of the two bases, the measuring instrument is located above one V-shaped opening, and a measuring rod of the measuring instrument stretches out in the direction of the V-shaped opening. The two side walls of each V-shaped opening are each provided with a protruding strip-shaped protruding strip used for abutting against the cylindrical face of the outer side of the lead screw, the length direction of the multiple protruding strips is perpendicular to the distribution direction of the two bases, and at least one base is provided with a round-rod-shaped ejector pin in a penetrating mode. The axial direction of the ejector pin is perpendicular to the distribution direction of the two bases, the ejector pin is in threaded connection with the bases, and one end of the ejector pin extends out of the V-shaped opening. The lead screw roundness measuring device can effectively measure the roundness of the cylindrical surface of the lead screw.

Description

Technical Field

[0001] This invention belongs to the field of mechanical technology and relates to a lead screw roundness measuring device. Background Technology

[0002] like Figure 1 As shown, a lead screw is generally cylindrical with helical threaded grooves on its outer surface. Adjacent threaded sections form a threaded cylindrical surface. The lead screw can be used with other components. For example, ball screws are the most commonly used transmission components in machine tools and precision machinery. Their main function is to convert rotary motion into linear motion or torque into axial reciprocating force. They also feature high precision, reversibility, and high efficiency, and are therefore widely used.

[0003] The roundness of a lead screw refers to the degree to which the outer surface of the lead screw, excluding the thread grooves, is nearly round; it is an important parameter of the lead screw. After the lead screw is manufactured, its roundness needs to be measured to determine whether it meets the requirements.

[0004] Currently, dial indicators are often used in conjunction with a base for measurement. During measurement, the leadscrew is placed horizontally on the base, and the measuring rod of the dial indicator rests against the cylindrical surface of the leadscrew. The dial indicator measures the roundness of the leadscrew's outer diameter by manually rotating and pulling the leadscrew. However, due to the helical grooves on the outer surface of the leadscrew, the measuring rod of the dial indicator is prone to falling into the grooves during the measurement process, affecting the normal measurement. This results in the roundness measurement of the leadscrew being time-consuming, laborious, and yielding poor measurement results. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a lead screw roundness measuring device, which solves the problem that the dial indicator rod easily falls into the lead screw thread groove during the existing lead screw roundness measurement process.

[0006] The objective of this invention can be achieved through the following technical solutions: A lead screw roundness measuring device includes a worktable, two bases spaced apart on the upper side of the worktable, a bracket fixed to one of the bases, and a measuring instrument connected to the bracket. Each of the two bases has a V-shaped opening at its top. The measuring instrument is located above one of the V-shaped openings, with its measuring rod extending towards the V-shaped opening. The device is characterized in that each V-shaped opening has protruding, elongated ridges on its two sidewalls for abutting against the outer cylindrical surface of the lead screw. The length direction of several of these ridges is perpendicular to the distribution direction of the two bases. At least one base has a cylindrical pin inserted through it, the axis of which is perpendicular to the distribution direction of the two bases. The pin is threaded to the base, and one end of the pin extends towards the V-shaped opening.

[0007] When measuring the roundness of the outer cylindrical surface of the lead screw, this lead screw roundness measuring device first places the lead screw horizontally within the V-shaped openings at the top of the two bases. The outer cylindrical surface of the lead screw abuts against the four protrusions on the sidewalls of the two V-shaped openings, providing four points of support for the lead screw and ensuring the stability of its position during the measurement process. Next, the ejector pin is rotated, causing it to move axially until its end engages with the threaded groove on the outer side of the lead screw, limiting the axial position of the lead screw. The measuring rod of the measuring instrument then rests against the outer cylindrical surface of the lead screw, and the lead screw is manually rotated. Because the ejector pin is engaged in the threaded groove and threadedly connected to the base, it will not axially retract during the rotation of the leadscrew. The end of the ejector pin continuously travels along the threaded groove of the leadscrew. The axial position of the cylindrical surface on the outer side of the leadscrew and the threaded groove remains constant. Therefore, the measuring rod of the measuring instrument can always rest against the helical cylindrical surface on the outer side of the leadscrew during its rotation, preventing the measuring rod from falling into the threaded groove due to axial movement of the leadscrew. This makes the measurement process more convenient and the measurement results better. Furthermore, using four protrusions perpendicular to the leadscrew to support it not only reduces the contact area between the leadscrew and the base, minimizing the influence of cylindrical surfaces with varying roundness on the measurement results, but also ensures that the measurement results are not affected by the machining accuracy of the threaded groove, guaranteeing the accuracy of the leadscrew roundness measurement.

[0008] In the aforementioned lead screw roundness measuring device, the base includes a seat body connected to the upper side of the worktable and a long, narrow swing arm. One end of the swing arm is connected to the side of the seat body via a fastener that passes vertically through the swing arm, and the ejector pin passes through the other end of the swing arm. When placing the lead screw, the fastener can be loosened, and the swing arm can be swung downwards around the axis of the fastener to clear the position. After placing the lead screw, the swing arm is swung back, and the swing arm and seat body are re-fixed by the fastener. The ejector pin is then axially pushed out and engaged in the threaded groove of the lead screw to achieve a limiting effect. Here, a detachable fastener is used to connect the swing arm and the seat body, allowing the swing arm to swing relative to the seat body. This allows the position of the ejector pin to also swing relative to the seat body, ensuring that the ejector pin and the threaded groove of the lead screw are aligned, thus guaranteeing the limiting effect.

[0009] In the aforementioned lead screw roundness measuring device, the base further includes a limiting frame fixed to the base body. The limiting frame is located on one side of the swing arm, and the swing arm can swing relative to the base body towards the limiting frame. A limiting screw is threaded onto the limiting frame, and when the limiting screw is screwed in along the thread, its end can abut against the side wall of the swing arm facing the limiting frame. The swing arm can swing relative to the base body to facilitate the alignment of the ejector pin with the thread groove of the lead screw. After the ejector pin is engaged in the thread groove, the swing arm can be held in place by screwing in the limiting screw to prevent the swing arm from wobbling. During measurement, the end of the lead screw is closer to the limiting frame, so that the swing arm will not swing due to excessive force pulling the lead screw, thus affecting the measurement results.

[0010] In the aforementioned lead screw roundness measuring device, the swing arm and the limiting frame are respectively connected to two adjacent side walls of the base. The swing arm is inclined relative to the vertical direction, and the end of the swing arm with the ejector pin is closer to the V-shaped opening than the other end. This inclined arrangement of the swing arm makes the ejector pin closer to the V-shaped opening, facilitating lead screw positioning. It also causes the end of the swing arm with the ejector pin to tilt upwards towards the base, facilitating the contact and limiting of the limiting screw on the limiting frame mounted on the other side of the base. Furthermore, mounting the swing arm and the limiting frame on two adjacent side walls of the base avoids interference when operating the ejector pin, swing arm, and limiting screw.

[0011] In the aforementioned lead screw roundness measuring device, a groove is provided on the worktable, and the extension direction of the groove is consistent with the distribution direction of the two bases. The base body is slidably connected to the groove on the worktable. The base also includes a strip-shaped adjusting component and a block-shaped slider horizontally slidably connected to the base body. One end of the adjusting component is connected to the slider, and the adjusting component can drive the slider to slide back and forth along the distribution direction of the two bases. One of the protrusions on the base is located on the slider. The base body can slide relative to the worktable, and the slider has a protrusion, that is, the side wall of the slider with the protrusion is one of the V-shaped side walls. The slider with the protrusion can slide relative to the base body, so that the two bases can adapt to the positioning of lead screws with different pitches, meet the detection requirements of the outer roundness of different lead screws, improve the applicability, and also ensure the measurement effect.

[0012] In the aforementioned lead screw roundness measuring device, the length direction of the adjusting member is consistent with the distribution direction of the two bases. The adjusting member is axially fixed to the base and can rotate circumferentially relative to the base. One end of the adjusting member is threadedly connected to the slider. The position of the slider is adjusted by rotating the adjusting member, which is convenient and has high adjustment accuracy.

[0013] In the aforementioned lead screw roundness measuring device, a dovetail groove is formed on the top of the base, and the length direction of the dovetail groove is consistent with the distribution direction of the two bases. The bottom of the slider is embedded in the dovetail groove. The upper side of the base has a vertically protruding, plate-shaped limiting part, and the side of the adjusting component has a recessed, annular limiting groove, into which the limiting part is engaged. The cooperation between the dovetail groove and the slider ensures that the slider can only move horizontally relative to the base along the length direction of the dovetail groove, facilitating the adjustment and control of the adjusting component.

[0014] In the aforementioned lead screw roundness measuring device, the support includes a vertically fixed, round rod-shaped upright and a rotating frame sleeved on the outside of the upright. The rotating frame can rotate circumferentially relative to the upright, and after rotation, it can be fixed to the upright by fasteners passing through the rotating frame. The measuring instrument is fixed on the rotating frame. The measuring instrument is connected to the upright via the rotating frame, allowing it to be swung aside to make room when placing the lead screw, and its position in the axial direction of the lead screw can be adjusted after placement to ensure that the measuring rod of the measuring instrument can abut against the cylindrical surface on the outside of the lead screw.

[0015] In the aforementioned lead screw roundness measuring device, all four protrusions are cylindrical. The cylindrical protrusions further reduce the contact area with the lead screw, forming point contact, while the cylindrical outer surface reduces damage to the outer surface of the lead screw.

[0016] Compared with existing technologies, this lead screw roundness measuring device has the following advantages: 1. By using a set-pin and a convex strip structure, the measuring rod of the measuring instrument can always rest against the spiral cylindrical surface on the outside of the lead screw when the lead screw rotates, preventing the measuring rod from falling into the thread groove due to axial movement of the lead screw. This makes the measurement process more convenient and the measurement effect better.

[0017] 2. The lead screw is supported by four cylindrical protrusions that are perpendicular to it. This not only reduces the contact area between the lead screw and the base and reduces the influence of cylindrical surfaces with different roundness on the measurement results, but also ensures that the four protrusions and the measuring rod are in contact with the cylindrical surface on the outside of the lead screw. This ensures that the measurement results are not affected by the machining accuracy of the thread groove and guarantees the accuracy of the lead screw roundness measurement.

[0018] 3. Through the sliding of the base, the sliding of the slider, and the rotation of the measuring instrument, this lead screw roundness measuring device can adapt to the measurement needs of lead screws of various specifications and ensure the measurement effect. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the lead screw structure in this lead screw roundness measuring device.

[0020] Figure 2 This is a schematic diagram of the structure of the lead screw roundness measuring device.

[0021] Figure 3 This is a cross-sectional structural diagram of the adjusting component and slider in this lead screw roundness measuring device.

[0022] Figure 4 This is a cross-sectional structural diagram of the measuring rod in this lead screw roundness measuring device.

[0023] In the diagram, 1. Lead screw; 1a. Threaded groove; 1b. Cylindrical surface; 2. Worktable; 2a. Slide groove; 3. Base; 3a. V-shaped opening; 3b. Protrusion; 3c. Seat body; 3d. Swing arm; 3e. Adjusting component; 3f. Slider; 3g. Limiting frame; 3h. Limiting part; 3i. Limiting groove; 4. Bracket; 4a. Upright rod; 4b. Rotating frame; 5. Measuring instrument; 5a. Measuring rod; 6. Ejector pin; 7. Limiting screw. Detailed Implementation

[0024] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0025] like Figure 1 As shown, the lead screw 1 is in the shape of a round rod, with a spiral threaded groove 1a on its outer side, and a threaded cylindrical surface 1b formed adjacent to the threaded groove 1a.

[0026] like Figure 2 As shown, this lead screw roundness measuring device includes a long, strip-shaped worktable 2, two bases 3, a bracket 4 fixed to one of the bases 3, and a measuring instrument 5 connected to the bracket 4. The top of the worktable 2 has a T-shaped groove 2a along its length. The bottoms of the two bases 3 have corresponding T-shaped blocks, and the two bases 3 are slidably connected to the worktable 2 through the cooperation of the T-shaped blocks and the T-shaped groove. The bracket 4 includes a cylindrical upright 4a fixed vertically to the base 3 and a rotating frame 4b sleeved on the outside of the upright 4a. The rotating frame 4b can rotate circumferentially relative to the upright 4a, and after rotation, it can be fixed to the upright 4a by fasteners passing through the rotating frame 4b. The measuring instrument 5 is vertically fixed to the rotating frame 4b, and its measuring rod 5a extends vertically downwards.

[0027] Since the two bases 3 have the same structure, the following explanation will take the structure of one of the bases 3 as an example.

[0028] The top of the base 3 has a V-shaped opening 3a for placing the lead screw 1. Both sidewalls of the V-shaped opening 3a are inclined relative to the vertical and horizontal directions. Each sidewall of the V-shaped opening 3a has a protruding, elongated cylindrical ridge 3b that abuts against the outer cylindrical surface 1b of the lead screw 1. The length direction of both ridges 3b is perpendicular to the distribution direction of the two bases 3. A rod-shaped ejector pin 6 is inserted through the side of the base 3 to extend into the threaded groove 1a of the lead screw 1. The ejector pin 6 can move along its axis relative to the base 3 and extend into the V-shaped opening 3a.

[0029] like Figure 3As shown, specifically, the base 3 includes a seat 3c slidably connected to the upper side of the worktable 2, a vertically arranged elongated swing arm 3d, a horizontally arranged elongated adjusting member 3e, and a block-shaped slider 3f disposed on the seat 3c. A dovetail groove is formed at the top of the seat 3c, the length direction of which is consistent with the distribution direction of the two bases 3. The bottom of the slider 3f engages with the dovetail groove, allowing the slider 3f to move back and forth along the groove. The top surface of the slider 3f is one sidewall of the V-shaped opening 3a, meaning one of the two protrusions 3b on the base 3 is located at the top of the slider 3f. The two protrusions 3b are staggered along the distribution direction of the two bases 3, so that they simultaneously abut against the spiral cylindrical surface 1b. The upper side of the base 3c has a vertically protruding, plate-like limiting part 3h. The length direction of the adjusting member 3e is consistent with the distribution direction of the two bases 3. The side of the adjusting member 3e has a recessed, annular limiting groove 3i. The limiting part 3h is engaged in the limiting groove 3i, so that the adjusting member 3e and the base 3c are axially fixed and the adjusting member 3e can rotate circumferentially relative to the base 3c. One end of the adjusting member 3e passes through one side of the slider 3f and is threadedly connected to the slider 3f. The other end of the adjusting member 3e has a handle.

[0030] One sidewall of the base 3c is inclined relative to the vertical direction. One side of the lower end of the swing arm 3d rests against the side of the base 3c and is fixed to the base 3c by a fastener that passes vertically through the lower side of the swing arm 3d. This causes the swing arm 3d to also be inclined relative to the vertical direction, with the upper end of the swing arm 3d closer to the V-shaped opening 3a than the lower end. The ejector pin 6 passes through the upper side of the swing arm 3d and is threadedly connected to it. In this embodiment, all the fasteners are screws; the end of the ejector pin 6 facing the V-shaped opening 3a has a convex curved surface.

[0031] When measuring the roundness of the outer cylindrical surface 1b of the lead screw 1, this lead screw roundness measuring device first performs position calibration of the base 3.

[0032] Specifically, the lead screw 1 is placed horizontally in the V-shaped opening 3a at the top of the two bases 3. The relative positions of the two bases 3 are adjusted so that the two protrusions 3b not on the slider 3f are respectively engaged in the threaded groove 1a of the lead screw 1. The positions of the slider 3f and the other two protrusions 3b are adjusted by rotating the adjusting piece 3e on the base 3 so that the other two protrusions 3b are also engaged in the threaded groove 1a of the lead screw 1. The position correction and adjustment of the two bases 3 and the slider 3f are then completed.

[0033] After that, as Figure 4 As shown, lift the lead screw 1 and move it slightly axially so that the four protrusions 3b abut against the cylindrical surface 1b on the outer side of the lead screw 1. The four protrusions 3b provide support for the lead screw 1 at four points, ensuring the stability of the position of the lead screw 1 during the measurement process.

[0034] Rotate the ejector pin 6 so that it moves inward and engages in the threaded groove 1a of the lead screw 1, limiting the axial position of the lead screw 1. Because the ejector pin 6 and the measuring rod 5a are not in the same vertical plane, the state of the ejector pin 6 engaging in the threaded groove 1a is not shown in the figure. If the position of the ejector pin 6 is not aligned with the position of the threaded groove 1a, loosen the fastener at the lower end of the swing arm 3d, move the swing arm 3d until the position of the ejector pin 6 is aligned with the threaded groove 1a of the lead screw 1, then tighten it again, and then push the ejector pin 6 into the threaded groove 1a of the lead screw 1.

[0035] Rotate the rotating frame 4b so that the lower end of the measuring rod 5a of the measuring instrument 5 abuts against the cylindrical surface 1b on the outside of the lead screw 1, then tighten the fasteners to fix the rotating frame 4b and the upright rod 4a.

[0036] Measurement begins with manual rotation of the lead screw 1. Because the ejector pin 6 is engaged in the threaded groove 1a, during the rotation of the lead screw 1, it undergoes axial movement while rotating circumferentially. The ejector pin 6 remains engaged with the threaded groove 1a, ensuring that the axial position of the outer cylindrical surface 1b and the threaded groove 1a remains constant throughout the rotation. Therefore, the measuring rod 5a of the measuring instrument 5 remains against the helical cylindrical surface 1b of the lead screw 1 throughout its rotation, meaning the measuring rod 5a travels in a helical manner relative to the lead screw 1, thus detecting the roundness of the helical cylindrical surface 1b. Here, a dial indicator can be used as the measuring instrument 5, and the error reading on the dial indicator is used to determine whether the roundness of the lead screw 1 meets the error requirements.

[0037] Furthermore, to prevent the ejector pin 6 on the swing arm 3d from getting stuck in the threaded groove 1a of the lead screw 1, and to avoid manually rotating the lead screw 1 to cause the ejector pin 6 to swing along the threaded groove 1a, the base 3 also includes a limiting frame 3g fixed to the seat body 3c. The limiting frame 3g and the seat body 3c are an integral structure to ensure strength. The limiting frame 3g is located on one side of the swing arm 3d, and the swing arm 3d can move closer to or away from the limiting frame 3g when swinging relative to the seat body 3c. A limiting screw 7 is threaded through and connected to the limiting frame 3g in the horizontal direction. The end of the limiting screw 7 faces the swing arm 3d, and when the limiting screw 7 is screwed in along the thread, its end can abut against the side wall of the swing arm 3d facing the limiting frame 3g, so as to prevent the swing arm 3g from swinging accidentally during the measurement process. In this embodiment, the swing arm 3d and the limiting frame 3g are located on two adjacent and mutually perpendicular side walls of the seat body 3c.

[0038] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A lead screw roundness measuring device, comprising a worktable (2), two bases (3) spaced apart on the upper side of the worktable (2), a bracket (4) fixed on one of the bases (3), and a measuring instrument (5) connected to the bracket (4), wherein the tops of the two bases (3) are provided with V-shaped openings (3a), and the measuring instrument (5) is located above one of the V-shaped openings (3a) with the measuring rod (5a) of the measuring instrument (5) extending toward the V-shaped opening (3a), characterized in that, Each of the V-shaped openings (3a) has a protruding, elongated ridge (3b) on each of its two sidewalls for abutting against the outer cylindrical surface (1b) of the lead screw (1). The length direction of several of the ridges (3b) is perpendicular to the distribution direction of the two bases (3). At least one base (3) is provided with a cylindrical pin (6). The axial direction of the pin (6) is perpendicular to the distribution direction of the two bases (3). The pin (6) is threaded to the base (3), and one end of the pin (6) extends toward the V-shaped opening (3a).

2. The lead screw roundness measuring device according to claim 1, characterized in that, The base (3) includes a seat (3c) connected to the upper side of the workbench (2) and a long swing arm (3d). One end of the swing arm (3d) is connected to the side of the seat (3c) by a fastener that passes vertically through the swing arm (3d), and the pin (6) is inserted through the other end of the swing arm (3d).

3. The lead screw roundness measuring device according to claim 2, characterized in that, The base (3) also includes a limiting frame (3g) fixed to the seat body (3c). The limiting frame (3g) is located on one side of the swing arm (3d) and the swing arm (3d) can swing relative to the seat body (3c) toward the limiting frame (3g). A limiting screw (7) is threadedly connected to the limiting frame (3g). When the limiting screw (7) is screwed along the thread, its end can abut against the side wall of the swing arm (3d) facing the limiting frame (3g).

4. The lead screw roundness measuring device according to claim 3, characterized in that, The swing arm (3d) and the limiting frame (3g) are respectively connected to two adjacent side walls on the base (3c). The swing arm (3d) is inclined relative to the vertical direction, and the end of the swing arm (3d) with the pin (6) is closer to the V-shaped opening (3a) than the other end.

5. The lead screw roundness measuring device according to claim 2, 3, or 4, characterized in that, The workbench (2) is provided with a slide groove (2a), and the extension direction of the slide groove (2a) is consistent with the distribution direction of the two bases (3). The base (3c) is slidably connected to the slide groove (2a) of the workbench (2). The base (3) also includes a strip-shaped adjustment member (3e) and a block-shaped slider (3f) slidably connected to the base (3c). One end of the adjustment member (3e) is connected to the slider (3f). The adjustment member (3e) can drive the slider (3f) to slide back and forth along the distribution direction of the two bases (3). One of the protrusions (3b) on the base (3) is located on the slider (3f).

6. The lead screw roundness measuring device according to claim 5, characterized in that, The length direction of the adjusting member (3e) is consistent with the distribution direction of the two bases (3). The adjusting member (3e) is axially fixed on the base (3c) and can rotate circumferentially relative to the base (3c). One end of the adjusting member (3e) is threadedly connected to the slider (3f).

7. The lead screw roundness measuring device according to claim 6, characterized in that, The top of the seat (3c) is provided with a dovetail groove, the length direction of which is consistent with the distribution direction of the two bases (3). The bottom of the slider (3f) is embedded in the dovetail groove. The upper side of the seat (3c) has a vertically protruding, sheet-like limiting part (3h). The side of the adjusting member (3e) has a recessed, annular limiting groove (3i). The limiting part (3h) is inserted into the limiting groove (3i).

8. The lead screw roundness measuring device according to claim 1, 2, 3, or 4, characterized in that, The bracket (4) includes a cylindrical upright (4a) fixed vertically on the base (3) and a rotating frame (4b) sleeved on the outside of the upright (4a). The rotating frame (4b) can rotate circumferentially relative to the upright (4a), and after the rotating frame (4b) rotates, it can be fixed to the upright (4a) by fasteners passing through the rotating frame (4b). The measuring instrument (5) is fixed on the rotating frame (4b).

9. The lead screw roundness measuring device according to claim 1, 2, 3, or 4, characterized in that, All four of the convex strips (3b) are cylindrical.

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