Inner aperture roundness measuring device and use method

Abstract

The invention provides an inner bore diameter roundness measuring device and a use method, the inner bore diameter roundness measuring device comprises a central cylinder, two ends of the central cylinder are provided with three groups of radial support rods synchronously driven by a bidirectional screw rod, end parts of the support rods are provided with rollers, and the rollers can automatically center and enable the central cylinder and a workpiece cylinder barrel to be coaxial; a rotating arm is arranged at one end of the central barrel, a telescopic rotating rod is arranged in the rotating arm, a dial indicator is arranged at the end of the rotating rod, and a measuring head of the dial indicator abuts against the inner wall of the cylinder barrel. The two-way lead screw is driven by the hand wheel, so that the supporting rod is expanded or contracted to adapt to different inner diameters; after the extension length of the rotating rod is adjusted and locked, the roundness can be measured by rotating the rotating arm; the whole device can move in the axial direction of the cylinder barrel, and detection of any section is achieved. The device is stable in structure, high in centering precision and simple and convenient to operate, effectively solves the problems of large roundness measurement error and low universality caused by eccentricity, difficult adjustment and poor stability in the prior art, and is suitable for high-precision roundness detection of cylinder barrels of various specifications.

Description

Technical Field

[0001] This invention relates to the field of measuring and testing instruments, and specifically to an internal diameter roundness measuring device and its usage method. Background Technology

[0002] In precision machining fields such as mechanical manufacturing, hydraulic components, and engine blocks, the roundness of the inner hole of a workpiece is one of the key geometric parameters for measuring its machining quality. Roundness error directly affects assembly accuracy, sealing performance, and service life; therefore, high-precision detection of the roundness of the inner hole is crucial.

[0003] Currently, common methods for measuring the roundness of internal holes mainly involve manual inspection using pneumatic gauges, coordinate measuring machines (CMMs), or handheld dial indicators with centering devices. However, existing technologies still have the following prominent problems in practical applications: Most traditional measuring devices rely on manual adjustment or a simple three-point support structure, making it difficult to ensure that the measuring reference axis is strictly aligned with the workpiece's inner hole axis. If the device is misaligned, even if the dial indicator reading is stable, the obtained data will contain systematic errors introduced by the installation offset, resulting in distorted roundness assessment.

[0004] Existing centering support structures are mostly fixed in size or manually adjustable, which cannot quickly adapt to workpieces with different inner diameters. Changing the workpiece often requires replacing the entire positioning component, which is cumbersome, inefficient, and fails to meet the flexible inspection needs of multi-variety, small-batch production scenarios.

[0005] In some devices, the measuring arm or sensor is prone to wobbling or displacement during rotational measurement, especially in long-stroke or large-diameter hole measurements. Furthermore, the sensor clamping mechanism lacks rigidity and is susceptible to vibration or operating forces, causing reading fluctuations and affecting repeatability and accuracy.

[0006] Traditional devices can only measure the roundness of a fixed cross section. If multiple axial positions need to be detected, repeated disassembly or repositioning is required, which is not only time-consuming, but may also reduce the overall detection reliability due to the accumulation of repeated positioning errors.

[0007] In summary, existing technologies for measuring the roundness of internal holes generally suffer from technical defects such as low centering accuracy, weak structural rigidity, inconvenient adjustment, poor versatility, and difficulty in achieving continuous measurement across the entire hole section. These defects severely restrict the implementation of high-precision and high-efficiency internal hole quality control. Summary of the Invention

[0008] The main objective of this invention is to provide an internal bore diameter roundness measuring device and its usage method, thereby solving the problems mentioned in the background art.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: including a central cylinder, with at least three radially extended support rods at both ends of the central cylinder, and the ends of the support rods abutting against the inner wall of the workpiece cylinder after being extended, so that the central cylinder and the workpiece cylinder are coaxial; The center cylinder has a rotating arm at its end, and a telescopic rotating rod is installed inside the rotating arm. A dial indicator is fixed at the end of the rotating rod. The measuring head of the dial indicator rests against the inner wall of the workpiece cylinder. The dial indicator is driven by rotating the rotating arm to measure the roundness of the inner bore diameter of the workpiece cylinder.

[0010] Preferably, the support rods at both ends of the central cylinder are mirror images of each other. Fixed supports are fixed at both ends of the central cylinder, and a sliding movable support is provided on one side of the fixed support. The end of the support rod is hinged to the fixed support, and the middle part of the support rod is hinged to the movable support through a push rod. The movable support slides, which in turn drives the push rod to rotate the support rod around the fixed support, so that the support rod can expand or contract.

[0011] Preferably, a rotating bidirectional lead screw is provided inside the central cylinder. The two ends of the bidirectional lead screw are supported and rotated inside the central cylinder by a first bearing and a third bearing. The two ends of the bidirectional lead screw are provided with threaded sleeves, and the movable support is fixedly connected to the sleeves. The rotation of the bidirectional lead screw drives the relative movement of the lead sleeves at both ends, thereby moving the movable support.

[0012] Preferably, multiple sliding grooves are provided on both sides of the central cylinder, a flange ring is provided on the outside of the threaded sleeve, the flange ring and the threaded sleeve are connected by multiple supports, the threaded sleeve is located inside the central cylinder and connected to the bidirectional threaded rod, the flange ring is located outside the central cylinder and connected to the movable support, and the supports slide within the sliding grooves.

[0013] Preferably, one end of the central cylinder is fixedly provided with an end cap, and the other end is fixedly provided with a locking sleeve. One end of the bidirectional lead screw passes through the locking sleeve and a handwheel is installed at its end. The locking sleeve is used to fix the rotation of the double-acting lead screw.

[0014] Preferably, an inner ring is provided on the inner side of the rotating arm end, and second bearings are provided on both sides of the inner ring. The second bearings are sleeved on the workpiece cylinder, and the locking sleeve and snap ring at the end of the workpiece cylinder abut against the second bearings on both sides of the rotating arm to limit and fix them.

[0015] Preferably, the rotating arm has a through groove extending to the top on its side, the rotating rod slides within the through groove, the rotating rod has an elongated slot, and the top of the rotating arm has at least two locking bolts located within the elongated slot. The top of the rotating arm is locked by tightening the locking bolts, thereby pressing and fixing the rotating rod.

[0016] Preferably, multiple friction pads are provided between the contact surfaces of the rotating arm and the rotating rod, and the friction pads are fitted onto the locking bolts.

[0017] Preferably, the end of the support rod is provided with a rotating roller, which abuts against the inner wall of the workpiece cylinder. The end face of the roller is arc-shaped to fit the inner arc of the workpiece cylinder.

[0018] A method for using an internal bore diameter roundness measuring device, comprising the following steps: S1. The support rod in the device retracts into the workpiece cylinder. By driving the handwheel to rotate, the multiple support rods around the center cylinder slowly unfold, so that the rollers at their ends abut against the inner wall of the workpiece cylinder. At this time, the center cylinder and the workpiece cylinder are coaxial. S2. Adjust the extension distance of the rotating rod on the rotating arm so that the measuring head of the dial indicator at its end is pressed against the inner wall of the workpiece cylinder and the locking bolt is tightened to lock and fix the rotating rod. S3. The entire device can move axially inside the workpiece cylinder via rollers, and the inner diameter roundness of the workpiece cylinder can be measured at any position by rotating the rotating arm to drive the dial indicator.

[0019] This invention provides an internal hole diameter roundness measuring device and its usage method, with the following advantages: 1. Three support rods are arranged in a mirror image at each end of the central cylinder. They are synchronously driven to unfold by a two-way lead screw. The three-point circle principle is used to automatically achieve coaxiality between the device and the workpiece cylinder, ensuring accurate measurement reference.

[0020] 2. The bidirectional lead screw, lead sleeve, and slide groove structure accurately converts rotational motion into linear motion, ensuring smooth and synchronous expansion and contraction of the support rod, and improving the rigidity and repeatability of the device.

[0021] 3. The rotating rod is telescopically adjustable within the through slot of the rotating arm. Combined with the long slot and double locking bolts, it enables the dial indicator measuring head to quickly adapt to different inner diameters. The friction pad and spring-type clamping structure enhance the locking reliability, prevent loosening during measurement, and ensure data accuracy.

[0022] 4. The handwheel drives the support to unfold, and the roundness inspection can be completed by manually rotating the rotating arm; the whole device can roll along the cylinder axis to realize the roundness measurement of any cross section without disassembly or repositioning. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall device of the present invention installed inside the workpiece cylinder; Figure 2 This is the present invention. Figure 1 Sectional view of AA; Figure 3 This is the present invention. Figure 2 Individual sectional view of the overall device; Figure 4 This is the present invention. Figure 2 BB section view; Figure 5 This is a cross-sectional view of the connection structure between the rotating rod and the rotating arm of the present invention; Figure 6 This is a cross-sectional view of the connection structure between the rotating arm and the central cylinder of the present invention; Figure 7 This is an axonometric view of the central cylinder structure of the present invention; In the diagram: 1. Workpiece cylinder; 2. Center cylinder; 201. Boss flange; 202. Slide groove; 203. Threaded hole; 204. Fixed support; 3. Support rod; 4. Push rod; 5. Movable support; 6. Threaded sleeve; 7. Support column; 701. Flange ring; 702. Double-acting screw; 8. End cap; 9. First bearing; 10. Dial indicator; 11. Rotating rod; 12. Long slot hole; 1201. Rotating arm; 13. Through groove; 1301. Inner ring; 1302. Second bearing; 14. Locking sleeve; 15. Locking clamp; 1501. Handwheel; 16. Locking bolt; 17. Snap ring; 18. Third bearing; 19. Friction pad; 20. Detailed Implementation

[0024] Example 1 like Figures 1-7 As shown, an inner diameter roundness measuring device includes a central cylinder 2, with at least three radially extended support rods 4 at both ends of the central cylinder 2. After the support rods 4 are extended, their ends abut against the inner wall of the workpiece cylinder 1 so that the central cylinder 2 and the workpiece cylinder 1 are coaxial. The center cylinder 2 has a rotating arm 13 at one end, and a telescopic rotating rod 12 is provided inside the rotating arm 13. A dial indicator 11 is fixed at the end of the rotating rod 12. The measuring head of the dial indicator 11 abuts against the inner wall of the workpiece cylinder 1. The dial indicator 11 is driven by rotating the rotating arm 13 to measure the roundness of the inner hole diameter of the workpiece cylinder 1.

[0025] In this example, there are three support rods 4 at each end of the central cylinder 2. When the support rods 4 at both ends are extended synchronously, they ensure that the central cylinder 2 is parallel to the axis of the workpiece cylinder 1. The three support rods 4 can automatically center when extended, thus achieving coaxiality between the central cylinder 2 and the workpiece cylinder 1. The telescopic rotating rod 12 causes the measuring head of the dial indicator 11 at its end to abut against the inner wall of the workpiece cylinder 1. Therefore, when the rotating arm 13 is driven to rotate, the inner diameter roundness of the workpiece cylinder 1 can be detected by the dial indicator 11.

[0026] like Figures 2-3As shown, the support rods 4 at both ends of the central cylinder 2 are mirror images of each other. Fixed supports 3 are fixed at both ends of the central cylinder 2. A sliding movable support 6 is provided on one side of the fixed support 3. The end of the support rod 4 is hinged to the fixed support 3. The middle part of the support rod 4 is hinged to the movable support 6 through a push rod 5. The movable support 6 is driven to slide, which in turn drives the push rod 5 to push the support rod 4 to rotate around the fixed support 3, so that the support rod 4 can be extended or retracted.

[0027] Multiple support rods 4 at both ends of the central cylinder 2 are arranged in a mirror image and unfolded to ensure its self-stability during the unfolding process. By driving the movement of the movable support 6, the push rod 5 is driven to push the support rod 4 to rotate and unfold, so as to be suitable for measuring cylinder cylinders 1 of workpieces with different inner diameters.

[0028] The fixed support 3 is fixedly connected to the boss flange 201 on the central cylinder 2 by bolts.

[0029] like Figure 3 As shown, a rotating bidirectional lead screw 8 is provided inside the central cylinder 2. The two ends of the bidirectional lead screw 8 are abutted against the central cylinder 2 and rotate through the first bearing 10 and the third bearing 19. The two ends of the bidirectional lead screw 8 are provided with threaded sleeves 7, and the movable support 6 is fixedly connected to the sleeves 7. The rotation of the bidirectional lead screw 8 drives the relative movement of the lead sleeves 7 at both ends, thereby moving the movable support 6.

[0030] The two ends of the bidirectional lead screw 8 have threads with opposite directions of rotation. By driving the bidirectional lead screw 8 to rotate, the threaded sleeves 7 at both ends can move relative to each other, thereby driving the multiple support rods 4 arranged in a mirror image to unfold.

[0031] like Figure 4 , 7 As shown, multiple sliding grooves 202 are provided on both sides of the central cylinder 2. A flange ring 702 is provided on the outside of the threaded sleeve 7. The flange ring 702 and the threaded sleeve 7 are connected by multiple support columns 701. The threaded sleeve 7 is located inside the central cylinder 2 and connected to the bidirectional threaded rod 8. The flange ring 702 is located outside the central cylinder 2 and connected to the movable support 6. The support column 701 slides in the sliding groove 202.

[0032] In this example, there are three corresponding slide grooves 202 and support columns 701. The support column 701 slides against the slide groove 202, which can convert the threaded rotation of the threaded sleeve 7 and the bidirectional lead screw 8 into linear movement, thereby driving the movable support 6 to move.

[0033] like Figure 3 , 6 As shown, one end of the central cylinder 2 is fixedly provided with an end cap 9, and the other end is fixedly provided with a locking sleeve 15. One end of the bidirectional screw 8 passes through the locking sleeve 15, and a handwheel 16 is installed at its end. The locking sleeve 15 is used to fix the rotation of the bidirectional lead screw 8.

[0034] The end cap 9 is used to seal one end of the central cylinder 2. The other end of the bidirectional screw 8 extends out of the central cylinder 2 and is equipped with a handwheel 16, which is convenient for manual driving to rotate. The locking sleeve 15 has a clamp locking structure at its end. The clamp is tightened by bolts and abuts against the bidirectional screw 8, thereby fixing its rotation.

[0035] like Figure 6 As shown, an inner ring 1302 is provided on the inner side of the end of the rotating arm 13, and second bearings 14 are provided on both sides of the inner ring 1302. The second bearings 14 are sleeved on the workpiece cylinder 1. The locking sleeve 15 and the snap ring 18 at the end of the workpiece cylinder 1 abut against the second bearings 14 on both sides of the rotating arm 13 to limit and fix them.

[0036] The rotating arm 13 rotates against the workpiece cylinder 1 via the second bearing 14. The two second bearings 14 clamp the inner ring 1302 inside the rotating arm 13, and limit and fix the two second bearings 14 by the locking sleeve 15 and the snap ring 18, ensuring the free rotation of the rotating arm 13 while fixing its displacement. The flange at the end of the locking sleeve 15 is connected to the threaded hole 204 at the end of the central cylinder 2 by bolts. The snap ring 18 is fixed in the slot 203 on the central cylinder 2 and protrudes against the second bearing 14.

[0037] like Figure 5 As shown, the rotating arm 13 is provided with a through groove 1301 extending to the top on the side. The rotating rod 12 slides in the through groove 1301. The rotating rod 12 is provided with a long slot hole 1201. The top of the rotating arm 13 is provided with at least two locking bolts 17, which are located in the long slot hole 1201. The top of the rotating arm 13 is locked by the locking bolt 17, thereby pressing and fixing the rotating rod 12.

[0038] The through slot 1301 divides the end of the rotating arm 13 into relatively retractable spring-loaded structures. These spring-loaded structures are locked by locking bolts 17, causing them to retract and press against both sides of the rotating rod 12, thus securing them. In this example, two locking bolts 17 are spaced apart along the length direction, restricting the rotating rod 12 from sliding along its length. The elongated slot 1201 on the rotating rod 12 allows it to move and extend within the through slot 1301 in the rotating arm 13, adjusting the extension distance of the dial indicator 11 to accommodate workpiece cylinders 1 with different inner diameters.

[0039] Multiple friction pads 20 are provided between the contact surfaces of the rotating arm 13 and the rotating rod 12, and the friction pads 20 are fitted onto the locking bolts 17. The end of the rotating arm 13 retracts, causing the friction pads 20 to abut against the rotating rod 12, thereby further fixing the rotating rod 12.

[0040] like Figures 1-3 As shown, the support rod 4 has a rotating roller at its end, which abuts against the inner wall of the workpiece cylinder 1. The end face of the roller is arc-shaped to fit the arc-shaped inner wall of the workpiece cylinder 1. The roller is made of nylon, and the roller allows the entire device to move axially within the workpiece cylinder 1, driving the dial indicator 11 to measure the roundness of the inner diameter of the workpiece cylinder 1 at any position.

[0041] Example 2 like Figures 1-7 As shown in Example 1, a method for using an inner hole diameter roundness measuring device is further explained, and the method steps are as follows: S1. The support rod 4 in the device retracts into the workpiece cylinder 1. By driving the handwheel 16 to rotate, the multiple support rods 4 around the center cylinder 2 slowly unfold, so that the rollers at their ends abut against the inner wall of the workpiece cylinder 1. At this time, the center cylinder 2 and the workpiece cylinder 1 are coaxial. S2. Adjust the extension distance of the rotating rod 12 on the rotating arm 13 so that the measuring head of the dial indicator 11 at its end is pressed against the inner wall of the workpiece cylinder 1, and tighten the locking bolt 17 to lock and fix the rotating rod 12. S3. The entire device can move axially within the workpiece cylinder 1 via rollers. By rotating the rotating arm 13, the dial indicator 11 can be driven to measure the roundness of the inner diameter of the workpiece cylinder 1 at any position.

[0042] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. An internal bore roundness measuring device characterized by: The center cylinder (2) is provided with at least three radially expanded support rods (4) at both ends, and the end portions of the support rods (4) abut against the inner wall of the workpiece cylinder (1) after being expanded, so that the center cylinder (2) is coaxial with the workpiece cylinder (1); The end portion of the center cylinder (2) is provided with a rotating rotating arm (13), and the rotating arm (13) is internally provided with a telescopic rotating rod (12), and the end portion of the rotating rod (12) is fixedly provided with a dial gauge (11), and the measuring head of the dial gauge (11) abuts against the inner wall of the workpiece cylinder (1), and the rotating arm (13) is rotated to drive the dial gauge (11) to measure the bore roundness of the workpiece cylinder (1).

2. The device of claim 1 wherein: The support rods (4) at both ends of the center cylinder (2) are mirror image arranged, and the center cylinder (2) is fixedly provided with a fixed support (3) at both ends, and one side of the fixed support (3) is provided with a sliding movable support (6), and the end portion of the support rod (4) is hinged to the fixed support (3), and the middle portion of the support rod (4) is hinged to the movable support (6) through a push rod (5); The movable support (6) is driven to slide, the push rod (5) is driven to push the support rod (4) to rotate around the fixed support (3), so that the support rod (4) is expanded or contracted.

3. The device of claim 2 wherein: The center cylinder (2) is internally provided with a rotating bidirectional screw rod (8), the two ends of the bidirectional screw rod (8) abut against the center cylinder (2) to rotate through a first bearing (10) and a third bearing (19), the two ends of the bidirectional screw rod (8) are provided with a threaded sleeve (7) connected in a threaded manner, and the movable support (6) is fixedly connected with the threaded sleeve (7); The bidirectional screw rod (8) is rotated to drive the two ends of the threaded sleeve (7) to move relatively, so as to drive the movable support (6) to move.

4. The device of claim 3 wherein: The two ends of the center cylinder (2) are provided with a plurality of sliding grooves (202) on the side, the outer side of the threaded sleeve (7) is provided with a flange ring (702), the flange ring (702) and the threaded sleeve (7) are connected through a plurality of support columns (701), the threaded sleeve (7) is connected with the bidirectional screw rod (8) inside the center cylinder (2), the flange ring (702) is connected with the movable support (6) outside the center cylinder (2), and the support column (701) slides in the sliding groove (202).

5. The device of claim 3 wherein: One end of the center cylinder (2) is fixedly provided with an end cover (9), the other end is fixedly provided with a locking sleeve (15), one end of the bidirectional screw rod (8) penetrates through the locking sleeve (15), and a hand wheel (16) is installed at the end portion of the bidirectional screw rod (8); The locking sleeve (15) is used for fixing the rotation of the bidirectional screw rod (8).

6. The device of claim 1 wherein: The end portion of the rotating arm (13) is internally provided with an inner ring (1302), the two sides of the inner ring (1302) are provided with a second bearing (14), the second bearing (14) is sleeved on the workpiece cylinder (1), and the locking sleeve (15) and the snap spring (18) at the end portion of the workpiece cylinder (1) abut against the second bearing (14) on the two sides of the rotating arm (13) to limit and fix the rotating arm (13).

7. The device of claim 1 wherein: The rotating arm (13) is laterally provided with a through groove (1301) penetrating to the top, the rotating rod (12) slides in the through groove (1301), the rotating rod (12) is provided with a long slot hole (1201), and the top of the rotating arm (13) is provided with at least two locking bolts (17), and the locking bolts (17) are located in the long slot hole (1201). The top of the rotating arm (13) is locked by the locking bolt (17), and the rotating rod (12) is pressed and fixed.

8. The device of claim 7 wherein: A plurality of friction pads (20) are arranged between the contact surface of the rotating arm (13) and the rotating rod (12), and the friction pads (20) are sleeved on the locking bolt (17).

9. The device for measuring the roundness of the inner hole diameter according to any one of claims 1 to 2, characterized in that: The end of the supporting rod (4) is provided with a rotating roller which abuts against the inner wall of the workpiece cylinder (1). The end surface of the roller is arc-shaped, and is used to fit the arc inner wall of the workpiece cylinder (1).

10. The use method of the inner hole diameter roundness measuring device according to any one of claims 1-9, the method steps are as follows: S1, the supporting rod (4) in the device is retracted into the inside of the workpiece cylinder (1), and is rotated by driving the hand wheel (16), so that the plurality of supporting rods (4) on the side of the center cylinder (2) are slowly unfolded, and the rollers at the ends thereof abut against the inner wall of the workpiece cylinder (1), at this time, the center cylinder (2) is coaxial with the workpiece cylinder (1); S2, the extension distance of the rotating rod (12) on the rotating arm (13) is adjusted, so that the measuring head of the dial gauge (11) at the end thereof abuts against and compresses the inner wall of the workpiece cylinder (1), the locking bolt (17) is tightened, and the rotating rod (12) is locked and fixed; S3, the whole device can move axially in the workpiece cylinder (1) through the rollers, and the inner diameter roundness of the workpiece cylinder (1) at any position can be measured by rotating the rotating arm (13) to drive the dial gauge (11).

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