An internal diameter π gauge for obtaining diameter size based on circumference expansion method
Through the inner diameter π gauges based on the perimeter expansion method, the circumference change is transformed into inner diameter changes using the principle of steel belt and π dots, which solves the problems of low efficiency and low accuracy of inner diameter detection of thin-walled annular parts such as flywheel rings, and realizes the Efficient and stable detection effect.
Patent Information
- Application Number
- CN201911062458.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-11-02
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2039-11-02
AI Technical Summary
The prior art is difficult to efficiently and accurately detect the inner diameter dimensions of thin-walled annular parts, especially after heat treatment of the flywheel ring gear with poor rigidity, resulting in low detection efficiency and high cost.
The inner diameter π gauge based on the perimeter expansion method is adopted, and the flexibility of the steel belt is used to closely fit the inner diameter of the workpiece. The circumference change is converted into the inner diameter change through the π point principle, and the cylinder and opening and closing lever mechanism are combined to achieve accurate detection.
It realizes efficient and stable inner diameter detection, simplifies the inspection process, reduces labor intensity and equipment costs, and improves detection accuracy and efficiency.
Smart Images
Figure CN110763108B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an inner diameter π gauge for obtaining diameter size based on a circumference expansion method, and is a detection tool for detecting the inner diameter size of a thin-walled annular part. Background Art
[0002] At present, some thin-walled annular workpieces are deformed during processing, assembly or heat treatment due to poor rigidity, which causes the detected inner diameter size of the parts to be distorted, thus posing a hidden danger to product quality.
[0003] The process flow of flywheel gear ring is generally: steel ring coiling → sawing → welding → slag removal → annealing → finishing → turning inner hole and end face → turning outer circle and end face → gear hobbing → chamfering → high frequency quenching → tempering → final size inspection, etc. During assembly, the flywheel gear ring is first heated and then pressed onto the outer diameter stop of the flywheel. After cooling, an interference fit is formed. The interference amount in this fit must be strictly controlled: too large will cause the gear ring to exceed the yield limit and break, and too small will easily fall off during operation, causing major quality risks.
[0004] When the car starts, the electric motor drives the engine through the flywheel ring gear to complete ignition.
[0005] Since the rigidity of the gear ring is very poor, it is easy to deform during heat treatment, and the change of metallographic structure causes the inner diameter size to be unstable, making the inner diameter size inspection in the last process very critical. It is usually the change in the shape of the flywheel gear ring detected by three coordinates after heat treatment. Conventional detection is to collect inner diameter data at multiple points such as 3 points, 6 points, 8 points or 16 points, and average the inner diameter to obtain the approximate inner diameter. The more points are collected, the closer to the actual inner diameter. But the biggest problem is that the efficiency will gradually decrease as the number of points increases. A large domestic state-owned enterprise has to inspect 5,000 flywheel gear rings per shift, with 12 inspectors working at the same time, which is very labor-intensive and inefficient. In order to reduce labor intensity and improve detection efficiency and accuracy, a scientific research team uses a laser detection method to select an average of more than 10 reference points on the inner diameter surface of the gear ring for every 1 mm length, and then use the least squares principle to obtain the inner diameter size through data processing. This method seems feasible in theory, but the efficiency is still not high, and the equipment cost is very high, which increases too much enterprise cost. There are also methods that use the maximum inscribed circle or the minimum circumscribed circle method for detection, but neither can obtain the true inner circle diameter; there are also some other methods that are not satisfactory. Summary of the invention
[0006] The purpose of the present invention is to provide an inner diameter π gauge for obtaining the diameter size based on the circumference expansion method. The flexibility of the steel strip is utilized to make the steel strip fit closely with the inner diameter of the workpiece, thereby obtaining the accurate change in the circumference of the workpiece, and then cleverly utilizing the π point principle to directly convert the circumference change into the inner diameter change. The method is simple, easy, stable and efficient, and solves a detection problem that has been plaguing us.
[0007] The technical solution of the present invention is implemented as follows: an inner diameter π gauge for obtaining diameter size based on the circumference expansion method, characterized in that: a bottom plate is arranged on the upper side of the control box and connected into an integral body by screws, a slot is provided at the lower end of the opening and closing lever, a narrow slit is provided at the upper end of the opening and closing lever, a C-shaped spring is clamped in the slot at the lower end of the opening and closing lever, the opening and closing lever is divided into left and right legs, the left leg and the right leg are connected by a central axis, and the left leg is fixed to the bottom plate by a fixed axis; the right leg performs an opening and closing action around the central axis; the cylinder support is fastened to the fixed axis, and the cylinder is fixed to the cylinder support by threads; the two ends of the steel belt are fixed in the narrow slit at the upper end of the opening and closing lever, the steel belt is sleeved outside the nylon cover and a gap is left, and the steel belt is placed on the support; the nylon cover is fastened to the support with screws, the support is fixed to the bottom plate, the measuring rod is connected to the hole of the same size on the right leg of the opening and closing lever by interference fit through the cylindrical part at the upper end, the sensor is connected to a digital display mounted on the sensor support, and the sensor support is fixed at the lower end of the central axis.
[0008] The measuring rod extends into the control box below through the hole on the bottom plate and opens and closes together with the right leg of the lever.
[0009] The sensor support is fixed at the lower end of the central shaft and extends deep into the control box.
[0010] The positive effect of the present invention is that neither the least squares method nor the minimum circumscribed circle method nor the maximum inscribed circle method can obtain the true value of the inner diameter of the workpiece. The present invention utilizes the flexibility of the steel belt to make the steel belt fit closely with the inner diameter of the workpiece, thereby obtaining the accurate change in the circumference of the workpiece, and then cleverly utilizes the π-point principle to directly convert the change in circumference into the change in inner diameter. It is simple, easy, stable and efficient, solves the detection problem, and has a very broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a structural schematic diagram of the present invention.
[0012] Figure 2 It is a schematic diagram of the top structure of the present invention.
[0013] Figure 3 It is a schematic diagram of a C-type spring of the present invention.
[0014] Figure 4 It is a schematic diagram of the opening and closing lever of the present invention.
[0015] Figure 5 It is a schematic diagram of the fixed axis of the present invention.
[0016] Figure 6 It is a schematic diagram of the central axis of the present invention.
[0017] Figure 7 It is a schematic diagram of a cylinder support of the present invention.
[0018] Figure 8 It is a schematic diagram of the steel strip of the present invention.
[0019] Fig. 9 It is a schematic diagram of the nylon cover of the present invention.
[0020] Fig.10 It is a schematic diagram of the support of the present invention.
[0021] Fig.11 It is a schematic diagram of the measuring rod of the present invention.
[0022] Fig.12 It is a schematic diagram of the sensor support of the present invention.
[0023] Fig.13 Schematic diagram of the principle of similar triangles.
[0024] Fig.14 It is a schematic diagram of the calibration piece of the present invention. DETAILED DESCRIPTION
[0025] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1-12 As shown, an inner diameter π gauge for obtaining diameter size based on the circumference expansion method is characterized in that: a bottom plate 2 is arranged on the top of a control box 1 and connected to form a whole by screws, a slot is provided at the lower end of an opening and closing lever 7, and a narrow slit is provided at the upper end, a C-type spring 3 is clamped in the slot at the lower end of the opening and closing lever 7, the opening and closing lever is divided into left and right legs, the left leg and the right leg are connected by a central axis 4, the left leg is fixed to the bottom plate 2 by a fixed axis 6; the right leg performs an opening and closing action around the central axis 4; a cylinder support 9 is fastened to the fixed axis 6, and a cylinder 10 is fixed to the cylinder support 9 by a thread, and its function is to overcome the spring force of the C-type spring so that the opening and closing lever Closed to facilitate loading and unloading of workpieces; the two ends of the steel belt 12 are fixed in the narrow gap at the upper end of the opening and closing lever 7, and the length of the steel belt is selected according to the inner circumference of the gear ring to be measured; the steel belt 12 is sleeved on the outside of the nylon cover 11 with a gap, and the steel belt is placed on the support 14; the nylon cover is fastened to the support 14 with screws, and the support 14 is fixed to the base plate 2, and the measuring rod 5 is connected with the hole of the same size on the right leg of the opening and closing lever through the cylindrical part at the upper end with an interference fit, and the measuring rod extends through the hole in the base plate to the control box below and opens and closes with the right leg of the lever; the sensor 8 is connected to an external digital display mounted on the sensor support 13.
[0026] The measuring rod 5 extends into the control box below through the hole in the bottom plate and opens and closes together with the right leg of the lever.
[0027] The sensor support is fixed to the lower end of the central shaft 4 and extends deep into the control box.
[0028] When measuring, first select the measuring point, i.e. the position of point π. Assume that the circumference of the inner circle of the workpiece is C and the diameter is D (=2R). Since the circumference: C=Dπ,
[0029] So: the change in circumference ΔC = ΔDπ, or: the change in diameter: ΔD = ΔC / π
[0030] Suppose the distance between the measuring point and the center of the circle is e, and let R / e=π.
[0031] According to the principle of similar triangles, Fig.13 As shown: ΔC / x=R / e=π, that is: x=ΔC / π
[0032] That is: diameter change ΔD = ΔC / π = x
[0033] Therefore: the diameter change ΔD is the value x measured at the measuring point (or called point π).
[0034] Conclusion: We can directly convert the circumference change ΔC into the diameter change ΔD without any further conversion.
[0035] The specific steps of the test are as follows: Before the test, we need to prepare a calibration piece 15, the inner diameter of which is equal to the ideal size (average size) of the inner diameter of the workpiece to be tested;
[0036] 1. First, place the calibration piece 15 as Fig.14 Sleeve it on the outside of the steel belt 12, then operate the control valve to make the cylinder piston move from left to right, release the opening and closing lever 7, and the opening and closing lever 7 expands the steel belt 12 on the inner circumferential surface of the calibration piece under the elastic force of the C-type spring 3;
[0037] 2. Then adjust the sensor measurement data transmitted from the display to 0;
[0038] 3. Finally, operate the control valve to move the cylinder piston from right to left, close the opening and closing lever 7, loosen the steel belt 12, and remove the calibration part.
[0039] Taking the flywheel gear ring as an example, when measuring the workpiece, you only need to use the flywheel gear ring instead of the calibration piece to repeat the above actions (just no longer need to reset), and the measurement data displayed on the display is the deviation between the actual size of the flywheel gear ring and the size of the calibration piece (ideal size). A positive value means that the workpiece size is too large, and a negative value means that the workpiece size is too small. If the display is replaced with an industrial computer, the actual inner diameter size of the workpiece can also be directly displayed through programming. Further data processing and storage can also be done: for example, a point diagram or a distribution curve diagram is obtained.
Claims
1. An internal diameter π gauge for obtaining diameter size based on the circumference expansion method, characterized in that: The bottom plate is arranged on the top of the control box and connected into a whole by screws. A slot is provided at the lower end of the opening and closing lever, and a narrow slit is provided at the upper end of the opening and closing lever. The C-shaped spring is clamped in the slot at the lower end of the opening and closing lever. The opening and closing lever is divided into left and right legs. The left leg and the right leg are connected by a central axis. The left leg is fixed to the bottom plate by a fixed axis; the right leg performs an opening and closing action around the central axis; the cylinder support is fastened to the fixed axis, and the cylinder is fixed to the cylinder support by threads; the two ends of the steel belt are fixed in the narrow slit at the upper end of the opening and closing lever, and the steel belt is sleeved outside the nylon cover The surface is fixed with a gap, and the steel belt is placed on the support; the nylon cover is fastened to the support with screws, the support is fixed to the base plate, the measuring rod is connected with the hole of the same size on the right leg of the opening and closing lever through the cylindrical part at the upper end with an interference fit, and a digital display is connected to the sensor externally and mounted on the sensor support, and the sensor support is fixed at the lower end of the central axis; the measuring rod extends into the control box below through the hole on the base plate and opens and closes with the right leg of the lever; the sensor support is fixed at the lower end of the central axis and extends deep into the control box.