CN211855698U - Special clamp for measuring rotational inertia of revolving body - Google Patents

Abstract

The utility model discloses a special clamp for measuring the moment of inertia of a revolving body, comprising a clamp body and a clamping device, the clamping device is arranged on the clamp body, the object to be measured of the revolving body is clamped by the clamping device, and the clamp body is provided with There are vertical contact surface, 45° contact surface and horizontal contact surface; the fixture body is fixedly connected to the measuring table through the vertical contact surface, 45° contact surface and horizontal contact surface respectively, so that the axis of the object to be measured of the rotating body is 90 degrees from the measuring table. °, 45° and 0°, realize the placement of the six postures of the object to be measured in the revolving body; the operator can fix the object to be measured in the revolving body on the top of the measuring table at a certain angle through this fixture, which has the advantages of safe operation and short placement cycle. , The object to be measured is placed at an accurate angle, the positioning and clamping are reliable, and the overall hoisting is stable.

Description

A special fixture for measuring the moment of inertia of a revolving body

technical field

The utility model relates to the technical field of clamps, in particular to a special clamp used for measuring the moment of inertia of a rotary body.

Background technique

The moment of inertia can directly reflect the difficulty of changing the rotational state of a rigid body. It has important physical significance in scientific experiments, engineering technology, aerospace, machinery and other industrial fields. The MPC inertial tester is a general center of mass and moment of inertia comprehensive test bench. It measures the coordinates of the center of mass, the mass, and the moment of inertia and inertial product through any axis by placing the object to be tested in six poses. The moment of inertia measurement method used by the instrument is the swing method, which indirectly obtains the moment of inertia by measuring the swing period of the rigid body.

According to the basic principle of moment of inertia measurement, the moment of inertia passing through any axis can be expressed by the following formula:

I _H =I _XX cos2α+I _YY cos ² β+I _ZZ cos ² δ-2I _XY cosαcosβ-2I _YZ cosβcosδ-2I _XZ cosαcosδ (1)

I _H is the moment of inertia over its center of mass; I _XX is the moment of inertia over its center of mass parallel to the X-axis; I _YY is the moment of inertia over its center of mass parallel to the Y-axis; I _ZZ - the rotation over its center of mass parallel to the Z-axis Inertia; I _XY , I _XZ , I _YZ are the inertia products in three directions respectively; α is the angle between the torsion bar rotation axis H and the X axis of the coordinate system on the object to be measured; β is the torsion bar rotation axis H and the object to be measured. The _{angle between} the _{Y axis} of the _{coordinate system} of the It is necessary to establish 6 equations, that is to say, let the object to be tested be placed on the measuring platform 6 times. It is not difficult to see from the formula (1), whether I _XX , I _YY , I _ZZ , I can be measured with high accuracy _XY , I _XZ , I _YZ , the key is how to accurately measure α, β, δ; in the process of using the MPC inertial tester to measure, put the object to be measured in six postures, and make the object to be measured and the measurement platform cannot be measured. There are relative motions. The six postures are obtained by placing the object to be measured on the measuring platform differently, so that the angles between the three coordinate axes and the rotating axis (the virtual straight line perpendicular to the measuring platform is called the rotating axis) are different. accomplish. The six poses are defined as pose one, pose two, pose three, pose four, pose five and pose six. According to the requirements of the MPC inertial tester, the angles between the three coordinate axes X, Y, Z of the object to be measured at the first attitude and the rotation axis are: 0°, 90°, 90°; the three coordinate axes of the object to be measured at the second attitude The angles between X, Y, Z and the rotation axis are: 90°, 0°, 90°; the angles between the three coordinate axes X, Y, Z of the object to be measured under the three attitudes and the rotation axis are: 45°, 45° °, 90°; the angles between the three coordinate axes X, Y, Z of the object to be measured under the posture and the rotation axis are: 90°, 90°, 0°; the three coordinate axes X of the object to be measured under the posture five , Y, Z and the included angles of the rotation axis are: 45°, 90°, 45°; the angles of the three coordinate axes X, Y, Z of the object to be measured under the attitude six and the rotation axis are: 90°, 45° , 45°. Each attitude needs to measure the moment of inertia loaded by the instrument and the moment of inertia of the instrument without load (including the fixture). The moment of inertia of the object to be measured is calculated by calculating the moment of inertia in the loaded state of the instrument minus the moment of inertia in the no-load state of the instrument.

Since the accuracy of the placement angle of the object to be tested and whether the object to be tested can be fixed above the bench directly affect the accuracy of the measurement results, the placement angle and fixation of the object to be tested have become the key steps in the measurement of the moment of inertia. Whether in the military or civilian fields, there are a large number of rotating body products with complex internal structures, such as rockets and guided missiles. The moment of inertia parameter is a very important parameter for such products, and it is often necessary to measure the moment of inertia. During the test, in order to make the slewing body can be accurately placed in six postures on the measuring bench, reduce the placement time, have reliable positioning and clamping, the overall hoisting is stable, the placement operation is safe, and some assemblies and fixtures do not interfere. , so it is very necessary to design a special fixture for the measurement of the moment of inertia of the rotating body.

Utility model content

The purpose of the utility model is to overcome the problems of difficulty in controlling the placement angle error of the object to be measured of the existing rotary body, long placement period and poor placement safety, and to provide a special fixture for measuring the moment of inertia of the rotary body.

The technical scheme that realizes the purpose of the present utility model is:

A special fixture for measuring the moment of inertia of a rotary body, including a fixture body and a clamping device, the clamping device is arranged on the fixture body, the object to be measured on the rotary body is clamped by the clamping device, and the fixture body is provided with a vertical contact surface, 45° contact surface and horizontal contact surface; the fixture body is fixedly connected to the measuring table through the vertical contact surface, 45° contact surface and horizontal contact surface respectively, so that the axis of the object to be tested of the rotating body is 90°, 45° and 90° respectively with the measuring table. 0°, to realize the placement of the six postures of the object to be measured in the rotating body.

The clamping device includes a pair of clamping mechanisms arranged symmetrically to each other, each clamping mechanism includes a test object support part and a test object clamp part, and the test object support part is provided on the position adjustment plate of the fixture body. The upper part can be moved on the position adjustment plate, and the two ends of the test object support part are respectively connected with the test object clamping part through the pressing screw; between clamping parts.

The object-to-be-measured support component includes a slide rail base plate, a guide rail is arranged on the slide rail base plate, sliders are respectively provided at both ends of the guide rail, each slider is provided with a DUT support block, and two DUTs support The block is symmetrical to the left and right to form a V-shaped support block. The object support block is provided with a movable first screw rod. One end of the first screw rod is movably connected to the bearing seat through the bearing, and the other end of the first screw rod is provided with a screw rod. The sleeve and the screw sleeve are connected with the handwheel through the bearing set on the bearing seat, and the first screw rod is driven by shaking the handwheel to move the support block of the object to be tested, thereby adjusting the distance between the two support blocks of the object to be tested And adapt to different sizes of rotating objects to be tested.

The object-to-be-measured clamping part includes a pressure plate, the middle of the pressure plate is provided with a second screw rod, the pressure plate is threadedly connected with the second screw rod, and the end of one end of the second screw rod is connected with the handwheel; The other end is gap-connected with the clamping block, and the end passes through the clamping block and is connected with a bolt through a washer.

The top end of the pressing screw rod is respectively connected with the two ends of the pressing plate with threads, and the top end is connected with the handwheel through the pressing plate, and the bottom end of the pressing screw rod is fixedly connected with the slide rail bottom plate of the object support member.

The said object support block is provided with a buffer block.

The buffer block is made of superior glue material, and the buffer block is provided with countersunk holes.

Said clamping block is a clamping block with the characteristics of V-shaped groove and rectangular groove.

The first screw rod is provided with positioning surfaces at both ends.

The object to be tested for the revolving body is a cylindrical, conical, or a revolving body with cylindrical and conical features, as well as a revolving body attachment with the feature of a side strip on the surface; the diameter of the object to be tested for the revolving body is 50-300mm, The length is 700-2500mm.

The utility model provides a special fixture for measuring the moment of inertia of a rotating body. The fixture body of the fixture has three contact planes with the measuring table surface, and the axis direction of the object to be measured of the rotating body can be adjusted through the contact between different planes and the measuring table surface. The included angles with the measuring table are 0°, 45° and 90° respectively. It is also more convenient to take out the object to be measured from the rotating body; and the fixture can be placed in all 6 postures required for measurement, and the object to be measured supports A hand wheel is installed on one side of the component, the object to be measured, and the pressing screw. By adjusting the hand wheel, the object to be tested of the rotary body can be better fixed on the fixture, and the rotary body of different diameters to be tested can be measured at the same time. The object, with the position adjustment plate, can measure the rotating object of different lengths. The fixture can measure the diameter range of the object to be measured in the rotating body is about 50mm~300mm, and the length range is about 700mm~2500mm; the overall design of the fixture is easy to fix on the workbench, safe operation, short placement cycle, stable overall lifting, positioning clip It is tight and reliable, the placement angle of the object to be tested on the rotating body is accurate, and the interference problem of the surface of the object to be tested on the rotating body, such as side wings and other accessories, is avoided. With this fixture, the operator can fix the object to be measured on the rotating body on the upper end of the measuring table at a certain angle, which has the advantages of safe operation, short placement cycle, accurate placement of the object to be measured, reliable positioning and clamping, and stable overall hoisting.

Description of drawings

Fig. 1 is an axonometric view of the overall structure of a special fixture for measuring the moment of inertia of a rotating body;

Fig. 2 is the structural representation of the fixture body;

3 is a schematic structural diagram of a clamping device;

Fig. 4 is the exploded structure schematic diagram of the object to be tested support member;

Fig. 5 is the exploded structure schematic diagram of the object-to-be-measured clamping part;

Fig. 6 is the structural representation of the first screw rod;

Fig. 7 is the schematic diagram of posture 4, posture 6 and posture 2 when the object to be measured of the revolving body is clamped;

Fig. 8 is the schematic diagram of attitude three and attitude five when the object to be measured of the revolving body is clamped;

Fig. 9 is the schematic diagram of attitude 1 when the object to be tested of the revolving body is clamped;

In the figure: 1. Fixture body 2. Rotary object to be measured 3. Clamping device 4. Position adjustment plate 5. Object to be measured support part 6. Object to be measured clamping part 7. Vertical contact surface of the fixture body 8. Fixture 45° contact surface of the body 9. Horizontal contact surface of the fixture body 10. Compression screw 11. Hand wheel 5-1. Bearing seat 5-2. Bearing 5-3. Screw sleeve 5-4. Buffer block 5 -5. Object support block 5-6. First screw 5-7. Slider 5-8. Slide rail bottom plate 5-9. Guide rail 5-10. Positioning surface 6-1. Gasket 6-2. The second screw 6-3. Pressing plate 6-4. Bolt 6-5. Clamping block.

Detailed ways

The content of the present utility model will be further described below in conjunction with the accompanying drawings and embodiments, but it is not intended to limit the present utility model.

Example:

As shown in Figures 1 and 2, a special fixture for measuring the moment of inertia of a rotary body includes a fixture body 1 and a clamping device 3. The clamping device 3 is provided on the fixture body 1, and the object to be measured 2 of the rotary body is The clamping device 3 clamps, and the fixture body 1 is provided with a vertical contact surface 7, a 45° contact surface 8 and a horizontal contact surface 9; The table is fixedly connected, so that the axis of the object to be measured 2 of the revolving body is 90°, 45° and 0° respectively with the measuring table, so that the six postures of the object to be measured 2 of the revolving body can be placed.

The object to be tested for the revolving body 2 is cylindrical, conical, or a revolving body with cylindrical and conical features, as well as a revolving body attachment with the feature of a side strip on the surface; the diameter of the object to be tested for the revolving body is 50-300mm , the length is 700-2500mm.

As shown in FIG. 3 , the clamping device 3 includes a pair of clamping mechanisms arranged symmetrically with each other, each clamping mechanism includes a test object supporting part 5 and a test object clamping part 6 , and the test object supports The part 5 is arranged on the position adjustment plate 4 of the fixture body 1, and can move on the position adjustment plate 4. The two ends of the object supporting part 5 are respectively connected with the object clamping part 6 through the pressing screw 10; The object to be tested 2 is clamped between the object-to-be-measured support part 5 and the object-to-be-tested clamping part 6; by adjusting the relative position of the object-to-be-measured support part 5 on the position adjustment plate 4, the rotating body to be measured can be realized Adjust the clamping position of the object 2 along the axis direction, so as to realize the clamping and measurement of rotating bodies of different lengths.

As shown in FIG. 4 , the object support member 5 includes a slide rail base plate 5-8. The slide rail base plate 5-8 is provided with guide rails 5-9, and the two ends of the guide rail 5-9 are respectively provided with sliders 5 -7, each slider 5-7 is provided with a test object support block 5-5, two test object support blocks 5-5 are symmetrical to form a V-shaped support block, and the test object support block 5-5 is equipped with There is a movable first screw 5-6, one end of the first screw 5-6 is movably connected with the bearing seat 5-1 through the bearing 5-2, and the other end of the first screw 5-6 is provided with a screw sleeve The cylinder 5-3 and the screw sleeve 5-3 are connected with the hand wheel 11 through the bearing 5-2 arranged on the bearing seat 5-1, and the first screw 5-6 is driven by shaking the hand wheel 11 to support the object to be tested The block 5-5 moves, thereby adjusting the distance between the two object-to-be-tested support blocks 5-5 to adapt to the rotating object to be tested 2 of different sizes.

As shown in FIG. 5 , the object-to-be-measured clamping part 6 includes a pressure plate 6-3, the middle part 6-3 of the pressure plate is provided with a second screw rod 6-2, the pressure plate 6-3 and the second screw rod 6-2 threaded connection, and the end of one end of the second screw rod 6-1 is connected to the handwheel 11; the other end of the second screw rod 6-2 is connected to the clamping block 6-5 with a gap, and the end passes through the clamping block 6 -5 is connected to the bolt 6-4 through the washer 6-1.

The top end of the pressing screw 10 is respectively connected with the two ends of the pressing plate 6-3 with threads, and the top end passes through the pressing plate 6-3 and is connected with the handwheel 11, and the bottom end of the pressing screw 10 is supported by the object to be measured. The slide rail base plates 5-8 of the component 5 are fixedly connected.

The said object support block 5-5 is provided with a buffer block 5-4.

The buffer block 5-4 is made of superior glue material, and the buffer block 5-4 is provided with counterbores, and the buffer block and the counterbore have the function of protecting the object to be tested in the rotating body.

Said clamping blocks 6-5 are clamping blocks with V-shaped grooves and rectangular grooves, which are convenient for clamping the rotating object 1 of different diameters, and at the same time avoid the interference phenomenon of the characteristic accessories of the side strips.

As shown in FIG. 6 , the first screw rod 5-6 is provided with positioning surfaces 5-10 at both ends.

The process of using the fixture is as follows:

When using the utility model, a Cartesian coordinate system is first established based on the object to be measured on the revolving body. For example, the axis direction of the object to be measured through the revolving body can be set as the x-axis, the upward direction is the y-axis, and the origin of the coordinates can be selected as the revolving body to be measured. The intersection of the axis of the object to be measured and the surface, in order to reduce the redundant workload when placing the posture, the order of defining the posture is: posture 4 → posture 6 → posture 2 → posture 3 → posture 5 → posture 1;

Clamping step: The worker fixes the horizontal contact surface 9 of the fixture body 1 on the measuring table, places the object support member 5 on the fixture body 1, selects the position through the position adjustment plate 4, and passes the bolts and nuts. Fix, rotate the first screw rod 5-6 by turning the hand wheel 11, the thread on the first screw rod 5-6 drives the screw rod sleeve 5-3 to rotate, and the screw rod sleeve 5-3 drives the support block of the object to be tested 5-5 moves, the object support block 5-5 drives the slider 5-6 to move, and the slider 5-6 moves on the guide rail 5-8, so that the object to be tested 2 of the rotating body has a better placement environment;

Lift and place the object-to-be-measured revolving body 2 on the object-to-be-measured support part 5, and rotate the handwheels 11 at both ends of the object-to-be-measured clamping part 6. The handwheel 11 drives the pressing screw 10 to move, and the pressing screw 10 moves. Drive the pressure plate 6-3 to move, the pressure plate 6-3 drives the second screw rod 6-2 to move, the second screw rod 6-3 drives the clamping block 6-5 to move, the handwheel 11 on the top of the second screw rod 6-2, The handwheel 11 drives the second screw rod 6-3 to move, the second screw rod 6-3 drives the clamping block 6-5 to move, and then cooperates with the handwheel 11 on the top of the pressing screw rod 10 to rotate the screw rod 10 more conveniently and quickly. The object to be tested 2 is fixed on the fixture body 1;

Steps for changing the attitude: Turn the handwheel 11 at the top of the pressing screw 10, take out the object-to-be-measured clamping part 6, rotate the object-to-be-measured 2 of the revolving body by a certain angle, and repeat the clamping steps to place the posture 6 and the posture 2 in sequence . The vertical contact surface 7 and the 45° contact surface 8 on the fixture body 1 are respectively made to be in fixed contact with the measuring table, so that all other postures of the object to be measured 2 of the rotating body can be placed. According to accompanying drawings 7, 8 and 9, the schematic diagrams of each posture are shown as: the schematic diagrams of posture four, posture six and posture two are shown in Figure 7; the schematic diagrams of posture three and posture five are shown in Figure 8; the schematic diagram of posture one As shown in Figure 9.

To measure the moment of inertia at the center of mass of the object to be measured 2 of the rotating body passing through any axis, the moment of inertia data of the measurement result can be converted to Euler angle.

Claims (9)

1. A special fixture for measuring rotational inertia of a revolving body is characterized by comprising a fixture body and a clamping device, wherein the clamping device is arranged on the fixture body, an object to be measured of the revolving body is clamped by the clamping device, and the fixture body is provided with a vertical contact surface, a 45-degree contact surface and a horizontal contact surface; the clamp body is fixedly connected with the measuring table through a vertical contact surface, a 45-degree contact surface and a horizontal contact surface respectively, so that the axis of the object to be measured of the revolving body forms 90 degrees, 45 degrees and 0 degrees with the measuring table respectively, and the placement of six postures of the object to be measured of the revolving body is realized;

the clamping device comprises a pair of clamping mechanisms which are symmetrically arranged, each clamping mechanism comprises an object to be tested supporting part and an object to be tested clamping part, the object to be tested supporting part is arranged on a position adjusting plate of the clamp body and can move on the position adjusting plate, and two ends of the object to be tested supporting part are respectively connected with the object to be tested clamping part through pressing screw rods; the rotary body object to be measured is clamped between the object supporting component and the object clamping component.

2. The special fixture for measuring rotational inertia of a revolving body according to claim 1, wherein the object-to-be-measured supporting member comprises a bottom plate of a slide rail, the bottom plate of the slide rail is provided with a guide rail, two ends of the guide rail are respectively provided with a slide block, each slide block is provided with an object-to-be-measured supporting block, the two object-to-be-measured supporting blocks are bilaterally symmetrical to form a V-shaped supporting block, a movable first lead screw is arranged in each object-to-be-measured supporting block, one end of the first lead screw is movably connected with the bearing block through a bearing, the other end of the first lead screw is provided with a lead screw sleeve, the lead screw sleeve is connected with a hand wheel through a bearing arranged on the bearing block, and the object-to-be-measured supporting blocks.

3. The special fixture for measuring the rotational inertia of the revolving body according to claim 1, wherein the object to be measured clamping part comprises a pressing plate, a second screw rod is arranged in the middle of the pressing plate, the pressing plate is in threaded connection with the second screw rod, and the end of one end of the second screw rod is connected with a hand wheel; the other end of the second screw rod is in clearance connection with the clamping block, and the end part of the second screw rod penetrates through the clamping block and is connected with the bolt through the gasket.

4. The special fixture for measuring the rotational inertia of a revolving body according to claim 1, wherein the top end of the pressing screw rod is respectively connected with both ends of the pressing plate and the screw thread, the top end of the pressing screw rod passes through the pressing plate and is connected with the hand wheel, and the bottom end of the pressing screw rod is fixedly connected with the bottom plate of the slide rail of the supporting component of the object to be measured.

5. The special fixture for measuring rotational inertia of a rotating body according to claim 2, wherein the supporting block of the object to be measured is provided with a buffer block.

6. The special fixture for measuring rotational inertia of a rotating body of claim 5, wherein the buffer block is made of a high-strength rubber material and is provided with a counter bore.

7. The special fixture for measuring rotational inertia of a body of revolution as claimed in claim 3, wherein the clamping block is a clamping block characterized by V-shaped groove and rectangular groove.

8. The special fixture for measuring rotational inertia of a revolving body according to claim 2, wherein two ends of the first lead screw are provided with positioning surfaces.

9. The special fixture for measuring the rotational inertia of the revolving body according to claim 1, wherein the revolving body object to be measured is cylindrical, conical, or a revolving body with characteristics of cylinder and cone, and a revolving body accessory with characteristics of edge strips and wings assembled on the surface; the diameter of the object to be measured of the revolving body is 50-300mm, and the length is 700-2500 mm.

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