Form and position tolerance detection tool and detection method

Abstract

The embodiment of the application discloses a kind of shape and position tolerance detection frock and detection method, wherein the frock includes: frock base, the frock base is used to support;Main rod, the main rod is vertically connected with the base;Auxiliary rod, the auxiliary rod is vertically connected with the main rod, the relative position of the auxiliary rod with the main rod is adjustable;Dial gauge, the dial gauge is connected to the end of the auxiliary rod by clamp table piece;The clamp table piece is used to adjust the position of dial gauge.Improve detection efficiency, reduce measurement cost.

Description

Technical Field

[0001] This invention relates to the field of workpiece measurement, and more particularly to a fixture and method for detecting geometric tolerances. Background Technology

[0002] During the production of a certain type of housing, it is necessary to measure the flatness of the discontinuous space plane installed in the inner cavity, the parallelism of the plane to the four mounting bases (reference planes) on the outside of the housing, and the parallelism between the end face of the DVL transducer mounting base under the four mounting bases (reference planes) and the reference.

[0003] There is currently no fast and effective method for detecting the form and position tolerances of this housing in the existing technology, and there is no effective solution to the above-mentioned problems in the existing technology. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a fixture and method for detecting geometrical tolerances. By adjusting the relative positions of the main rod and the auxiliary rod, as well as the position of the dial indicator, various indicators can be measured quickly and accurately, thus solving the problem that existing technologies cannot quickly and effectively detect geometrical tolerances.

[0005] To achieve the above objectives, this invention provides a form and position tolerance inspection fixture, comprising: a fixture base for support; a main rod perpendicularly connected to the base; a secondary rod perpendicularly connected to the main rod, the relative position of the secondary rod and the main rod being adjustable; and a dial indicator connected to the end of the secondary rod via a clamping device; the clamping device being used to adjust the position of the dial indicator.

[0006] Alternatively, the bottom surface of the tooling base may be provided with multiple anti-slip grooves.

[0007] Optionally, the main rod and the auxiliary rod are connected by an adapter plate; the adapter plate includes two orthogonal eccentric through holes, which respectively allow the main rod and the auxiliary rod to pass through; each eccentric through hole has a threaded hole on its front side, and a knob screw is provided in the threaded hole for fixing the main rod and the auxiliary rod.

[0008] Further optionally, the main rod has a length of 400mm; the secondary rod has a length of 500mm.

[0009] Alternatively, the main rod is threadedly connected to the tooling base and fixed by a lock nut.

[0010] On the other hand, the present invention also provides a form and position tolerance detection method for detecting a housing with four bosses in the inner cavity and four mounting bases and a transducer mounting base on the outer wall. The method uses the aforementioned form and position tolerance detection fixture: when measuring the flatness of the boss surfaces of the four bosses, a dial indicator is adjusted using a clamping device to contact the left front boss, with a preload; the fixture base is moved so that the dial indicator collects N measurement values ​​at each of the boss surfaces of the left front, left rear, right front, and right rear bosses; the flatness error of the boss surfaces formed by the four bosses is calculated based on the maximum and minimum measurement values; when measuring the parallelism between the boss surfaces of the four bosses and the bottom surface of the mounting base, a dial indicator is adjusted using a clamping device to contact the left front boss, with a preload; the fixture base is moved along the housing axis so that the dial indicator slides from the left front boss to the left... The dial indicator is moved from the rear left boss to the front left boss, and the maximum and minimum measured values ​​are recorded during the movement. The dial indicator is then adjusted using a clamping device to contact the front right boss with a pre-compression allowance. The fixture base is moved along the housing axis to slide the dial indicator from the front right boss to the rear right boss, and then back to the front right boss, recording the maximum and minimum measured values ​​during the movement. The first parallelism error is calculated based on the maximum and minimum measured values ​​from the two measurements. When measuring the parallelism between the transducer mounting base and its bottom surface, the dial indicator is adjusted using a clamping device to mount the dial indicator with its measuring head facing upwards and in contact with the end face of the transducer mounting base with a pre-compression allowance. The fixture base is moved to move the dial indicator from left to right along a sinusoidal measurement path on the end face of the transducer mounting base, recording the maximum and minimum measured values ​​during the movement and calculating the second parallelism error.

[0011] The above technical solution has the following beneficial effects: the above-mentioned geometric tolerance inspection fixture can quickly complete the measurement of various indicators, improve measurement efficiency, and reduce inspection costs; this inspection fixture, when used in conjunction with a parallel block, can also inspect the flatness, parallelism, and symmetry of other medium and large shells, and has high versatility. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the form and position tolerance inspection fixture provided in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the adapter plate provided in an embodiment of the present invention.

[0015] Reference numerals in the attached diagram: 1-Main rod; 2-Secondary rod; 3-Adapter plate; 301-Eccentric through hole; 302-Threaded hole; 4-Tooling base; 5-Locking nut; 6-Knob screw; 7-Dial indicator; 8-Clamping component. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] An existing housing has discontinuous planes on its inner sidewalls, namely two mounting plates installed opposite each other. Each mounting plate has two bosses. There are four mounting bases on the outer wall of the housing. Every two mounting bases are on the same horizontal line. There is also a transducer mounting seat on the outer wall of the housing for installing a DVL transducer. The transducer mounting seat is located on the central axis of the horizontal line where the two mounting bases are located. This central axis is also the axis of symmetry of the two mounting plates.

[0018] To enable rapid and effective flatness and parallelism inspection of the housing, this invention provides a form and position tolerance inspection fixture. Figure 1 This is a schematic diagram of the form and position tolerance inspection fixture provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the fixture includes: a fixture base 4 for support; a main rod 1, which is vertically connected to the base; a secondary rod 2, which is vertically connected to the main rod 1, and the relative position of the secondary rod 2 and the main rod 1 is adjustable; and a dial indicator 7, which is connected to the end of the secondary rod 2 via a clamp 8 for adjusting the position of the dial indicator 7.

[0019] like Figure 1 As shown, the tooling base 4 is sized according to the weight and length of the main rod 1 and the auxiliary rod 2, ensuring the stability of the entire tooling. The bottom surface of the base is placed on the worktable, and its flatness must be guaranteed. The main rod 1 is vertically connected to the top surface of the base, and the auxiliary rod 2 is vertically connected to the main rod 1. The height of the auxiliary rod 2 on the main rod 1 and the length of the auxiliary rod 2 passing through the main rod 1 are adjustable, meaning the relative position of the auxiliary rod 2 and the main rod 1 is adjustable. A dial indicator 7 is connected to the end of the auxiliary rod 2 via a clamp 8. The clamp 8 controls the adjustment of the position of the dial indicator 7 to meet different measurement needs.

[0020] As an optional implementation, the bottom surface of the tooling base 4 is provided with multiple anti-slip grooves.

[0021] like Figure 1As shown, the bottom surface of the tooling base 4 is provided with multiple anti-slip grooves to ensure stability during movement.

[0022] As an optional implementation, the anti-slip groove has a 2×1 dimension.

[0023] As an optional implementation, the main rod 1 and the auxiliary rod 2 are connected by an adapter plate 3. The adapter plate 3 includes two orthogonal eccentric through holes 301, which allow the main rod 1 and the auxiliary rod 2 to pass through respectively. Each eccentric through hole 301 has a threaded hole 302 on its front side, and a knob screw 6 is provided in the threaded hole for fixing the main rod 1 and the auxiliary rod 2.

[0024] like Figure 1 As shown, the main rod 1 and the auxiliary rod 2 are connected via an adapter plate 3. Figure 2 As shown, the adapter plate 3 includes two orthogonal eccentric through holes 301. These two orthogonal eccentric through holes 301 allow the auxiliary rod 2 and the main rod 1 to pass through respectively. Both sides of the two eccentric through holes 301 are provided with threaded holes 302. The knob screw 6 can pass through the threaded holes 302 to adjust the connection between the main rod 1 and the auxiliary rod 2 on the adapter plate 3, thereby adjusting the relative position of the main rod 1 and the auxiliary rod 2.

[0025] As an optional implementation, the threaded hole is selected as an M8 threaded hole.

[0026] As an optional implementation, the main rod 1 has a length of 400mm; the secondary rod 2 has a length of 500mm.

[0027] The housing diameter plus the DVL transducer mounting base is 742mm, and the length is 400mm. Considering this housing, the height of the main rod 1 is: the height of the transducer mounting base plus the height from the reference to the measured plane plus the height from the reference plane to the edge of the housing, with a total length of 400mm. The secondary rod 2 is considered from two aspects: firstly, the total depth of the housing is 377mm, and secondly, for assembly stability, it is a protruding part fixed to the main rod 1 via the adapter plate 3. The size of the secondary rod 2 is set to 500mm.

[0028] As an optional implementation, the main rod 1 is threadedly connected to the tooling base 4 and fixed by a locking nut 5.

[0029] like Figure 1 As shown, one end of the main rod 1 is provided with an external thread, which matches the internal thread of the tooling base 4, thereby being stably installed on the tooling base 4 and tightened by the locking nut 5.

[0030] This invention also provides a geometrical tolerance inspection method for inspecting a housing with four bosses in its inner cavity, four mounting bases on its outer wall, and a transducer mounting seat. The method utilizes the aforementioned geometrical tolerance inspection fixture.

[0031] S1. Place the bottom surface of the mounting base of the housing to be tested facing down and support it on the platform with parallel blocks;

[0032] During measurement, the bottom surface of the mounting base is used as the reference surface, and the shell to be measured is supported on the platform using parallel blocks.

[0033] S2. Place the tooling base on the platform and adjust the relative positions of the main rod and the auxiliary rod according to the size of the shell being measured;

[0034] Place the assembled fixture on the platform, ensuring its base is in stable contact with the platform. Check that the pointer of the universal dial indicator is flexible and intact. Attach the dial indicator to the end of the auxiliary rod. Adjust the knob screw on the adapter plate to position the main and auxiliary rods appropriately; this position is determined by the length of the housing to be measured and the measured location.

[0035] S3. Adjust the dial indicator using a clamping device until it contacts the part to be measured, and move the fixture base to take measurements to obtain the corresponding error values, including:

[0036] S301. When measuring the flatness of the boss surfaces of the four bosses, use a clamping device to adjust the dial indicator so that it contacts the left front boss and leaves a preload; move the tooling base so that the dial indicator collects N measurement values ​​at each of the boss surfaces of the left front boss, left rear boss, right front boss and right rear boss, and calculate the flatness error of the boss surfaces formed by the four bosses based on the maximum and minimum measurement values ​​among all the measurement values.

[0037] The process requires the flatness of the four boss surfaces to be no greater than 0.1, therefore, the flatness of the boss surfaces needs to be tested. First, adjust the dial indicator to zero, and adjust the clamping parts at the end of the auxiliary rod so that the dial indicator contacts the left front boss of the housing to be tested, with a certain preload. Move the entire fixture and measure 9 points on the left front boss. Push the measuring fixture base forward and measure 9 points on the left rear boss. Move the fixture out, adjust the appropriate position, and use the same method to measure 9 points on the right front and right rear. Calculate the maximum and minimum values ​​of the data for the four boss surfaces. Then, the flatness error f1 of the boss surface formed by the four bosses is equal to the maximum value minus the minimum value.

[0038] S302. When measuring the parallelism between the boss surfaces of the four bosses and the bottom surface of the mounting base, use a clamping device to adjust the dial indicator so that it contacts the left front boss and leaves a preload. Move the fixture base along the housing axis so that the dial indicator slides from the left front boss to the left rear boss, and then from the left rear boss to the left front boss. Record the maximum and minimum measured values ​​during the movement. Use a clamping device to adjust the dial indicator so that it contacts the right front boss and leaves a preload. Move the fixture base along the housing axis so that the dial indicator slides from the right front boss to the right rear boss, and then from the right rear boss to the right front boss. Record the maximum and minimum measured values ​​during the movement. Calculate the first parallelism error based on the maximum and minimum measured values ​​in the two measurement processes.

[0039] The process requires that the parallelism between the four boss surfaces and the bottom surface of the mounting base be no greater than 0.1. When this parallelism needs to be checked, first adjust the dial indicator to zero, adjust the clamping parts at the end of the auxiliary rod so that the dial indicator contacts the left front boss of the housing to be measured, with a certain preload. Move the entire fixture along the housing axis, from left front to left rear, and then back to left front, recording the maximum and minimum values ​​during the measurement process; move the entire measuring fixture along the housing axis, from right front to right rear, and then back to right front, recording the maximum and minimum values ​​during the measurement process; statistically compare the maximum and minimum values ​​in the two measurement processes, and then calculate the first parallelism using the following formula: Parallelism error f2 = maximum value - minimum value.

[0040] S303. When measuring the parallelism between the transducer mounting base and the bottom surface of the mounting base, use a clamping device to adjust the dial indicator so that the measuring head of the dial indicator is facing upwards and in contact with the end face of the transducer mounting base, leaving a pre-compression amount. Move the tooling base so that the dial indicator moves from left to right along a sinusoidal measurement path on the end face of the transducer mounting base. Record the maximum and minimum measured values ​​during the movement and calculate the second parallelism error.

[0041] The process requires that the parallelism between the bottom surface of the transducer mounting base and the mounting plate be no greater than 0.1. When this parallelism needs to be checked, zero the dial indicator, adjust the knob of the clamp to mount the dial indicator with the measuring head facing upwards, and ensure that the dial indicator is in contact with the end face of the transducer mounting base with a certain preload. Move the entire measuring fixture and measure along a sinusoidal (S-shaped) measurement path from left to right on the circular end face of the transducer mounting base. Record the maximum and minimum values ​​during the measurement process. The second parallelism error f3 = maximum value - minimum value.

[0042] The above technical solution has the following beneficial effects: the above-mentioned geometric tolerance inspection fixture can quickly complete the measurement of various indicators, improve measurement efficiency, and reduce inspection costs; this inspection fixture, when used in conjunction with a parallel block, can also inspect the flatness, parallelism, and symmetry of other medium and large shells, and has high versatility.

[0043] The above-described specific embodiments of the invention further illustrate the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above content is only for specific embodiments of the invention and is not intended to limit the scope of protection of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A form and position tolerance inspection method, used to inspect a housing with four bosses in its inner cavity, four mounting bases on its outer wall, and a transducer mounting seat using a form and position tolerance inspection fixture, wherein every two mounting bases are on the same horizontal line, and the transducer mounting seat is located on the central axis of the two horizontal lines on which the mounting bases are located, the form and position tolerance inspection fixture comprising: Tooling base, the tooling base being used for support; Main rod, which is perpendicularly connected to the tooling base; A secondary rod is perpendicularly connected to the main rod, and the relative position of the secondary rod and the main rod is adjustable. A dial indicator is connected to the end of the secondary rod via a clamping device. The clamping device is used to adjust the position of the dial indicator. The bottom surface of the fixture base is provided with multiple anti-slip grooves. The main rod and the secondary rod are connected via an adapter plate. The adapter plate includes two orthogonal eccentric through holes, which respectively allow the main rod and the secondary rod to pass through. Each eccentric through hole has a threaded hole on its front side, and a knob screw is provided in the threaded hole for fixing the main rod and the secondary rod. The length of the main rod is 400mm. The length of the secondary rod is 500mm. The main rod is threadedly connected to the fixture base and fixed by a lock nut. Its characteristics are: The four mounting bases of the housing to be tested are placed face down and supported on the platform by parallel blocks; Place the tooling base on the platform and adjust the relative positions of the main rod and the auxiliary rod according to the size of the shell being measured; The dial indicator is adjusted using a clamping device to bring it into contact with the part to be measured. The fixture base is then moved to perform the measurement, and the corresponding error values ​​are obtained, including: When measuring the flatness of the four boss surfaces, use a clamping device to adjust the dial indicator so that it contacts the left front boss and leaves a preload; move the tooling base so that the dial indicator collects N measurement values ​​at each of the left front boss, left rear boss, right front boss and right rear boss surfaces; calculate the flatness error of the boss surface formed by the four bosses based on the maximum and minimum measurement values ​​among all the measurement values. When measuring the parallelism between the boss surfaces of the four bosses and the bottom surface of the mounting base, use a clamping device to adjust the dial indicator so that it contacts the left front boss with a preload. Move the fixture base along the housing axis so that the dial indicator slides from the left front boss to the left rear boss, and then back from the left rear boss to the left front boss. Record the maximum and minimum measured values ​​during the movement. Use a clamping device to adjust the dial indicator so that it contacts the right front boss with a preload. Move the fixture base along the housing axis so that the dial indicator slides from the right front boss to the right rear boss, and then back from the right rear boss to the right front boss. Record the maximum and minimum measured values ​​during the movement. Calculate the first parallelism error based on the maximum and minimum measured values ​​from the two measurement processes. When measuring the parallelism between the transducer mounting base and the bottom surface of the mounting base, use a clamping device to adjust the dial indicator so that the measuring head of the dial indicator is facing upwards and in contact with the end face of the transducer mounting base, leaving a preload. Move the tooling base so that the dial indicator moves from left to right along a sinusoidal measurement path on the end face of the transducer mounting base. Record the maximum and minimum measured values ​​during the movement and calculate the second parallelism error.

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