Negative wave generating device

Abstract

The negative wave generating device comprises a negative wave generator with a cylinder barrel piston rod, a supporting frame supported at the bottom of a cylinder barrel and an impact head connected to the piston rod, the lower end of the piston rod penetrates through the cylinder barrel and extends downwards to form an adjusting end, and a stepped blind hole is formed in the center of the end face of the adjusting end. The upper hole body is small in diameter, the lower hole body is large in diameter, the conical hole body is connected with the upper hole body and the lower hole body, an upper adjusting hole communicated with the upper sealing cavity and the upper hole body and a lower adjusting hole communicated with the lower sealing cavity and the lower hole body are formed in the outer circumferential face of the piston rod, and an adjusting rod is inserted into the stepped blind hole and is in threaded connection with the stepped blind hole. The upper end part of the conical hole body is provided with a matching surface matched with the conical surface of the conical hole body, so that the upper hole body and the lower hole body can be isolated through the fitting and abutting of the matching surface and the conical surface during screwing, and a gap for communicating the upper hole body and the lower hole body can be formed through the separation of the matching surface and the conical surface during loosening, and the adjustment of negative pulse waves is realized; the device is suitable for a high-precision double-wave impact test.

Description

Technical Field

[0001] The present invention belongs to the technical field of impact test equipment, and in particular relates to a negative wave generating device suitable for a high-precision double-wave impact test. Background Art

[0002] The double-wave impact test is widely used in underwater non-contact impact simulation, which requires the impact input to be in the form of positive and negative double pulse waves and impact spectrum. In the prior art, the double-wave impact test mostly uses a damper as a negative wave generating device to provide a negative pulse wave, but the damping force of this type of damper is mostly difficult to adjust, and the negative pulse wave cannot be adjusted, and it can only adapt to a narrow range of double-wave impact tests. To solve this problem, a piston-type negative wave generating device with adjustable negative pulse waves has appeared on the market. For example, Chinese patent CN115420629A discloses this type of negative wave generating device. The device sets a pair of air leakage holes on the edge of the piston, and then inserts adjustment rods of different diameters into the air leakage holes to control the flow of the medium in the air leakage holes, thereby adjusting the falling time of the second half of the negative half-sine pulse wave to achieve the adjustment of the negative pulse wave. However, this solution requires the adjustment rod to be kept in the air leakage hole while the piston reciprocates up and down. Axial rotation is inevitable during the process, which can easily cause the outer wall of the adjusting rod to fit against the inner wall of the air bleed hole and generate friction. After long-term use, the original aperture of the air bleed hole will be changed, thereby affecting the flow rate and the accuracy of the double-wave impact test results. It is not applicable to the double-wave impact test with high precision requirements. Furthermore, the aperture, hole wall verticality and smoothness of the air bleed holes on both sides must be consistent, and the diameter, outer wall verticality and smoothness of the adjusting rods on both sides must also be consistent. Otherwise, after the adjusting rod is inserted into the air bleed hole, the dimensional deviation of the flow gap on both sides is large, which can easily lead to inconsistent force on both sides of the piston (paragraph 0074 of the scheme description also clearly records the method of passing the piston shaft through the lower cover to assist in balancing the pressure on both sides), affecting the sealing and service life of the piston shaft. Higher consistency requirements will also make the processing of parts difficult, making the overall cost of the negative wave generating device higher. Summary of the invention

[0003] The purpose of the present invention is to overcome one or more shortcomings in the prior art and to provide a negative wave generating device suitable for high-precision dual-wave impact testing.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is that the negative wave generating device comprises:

[0005] A negative wave generator, the negative wave generator comprises a cylinder, a piston and a piston rod, the cylinder is provided with a sealed cavity, the piston is movably arranged in the sealed cavity, the outer circumferential surface of the piston is dynamically sealed with the inner wall surface of the sealed cavity, and the sealed cavity is divided into an upper sealed cavity and a lower sealed cavity, the piston rod is coaxially penetrated on the piston, the upper end of the piston rod passes through the cylinder and extends upward to form a connecting end, and the lower end of the piston rod passes through the cylinder and extends downward to form an adjusting end;

[0006] A support frame, the support frame is supported on the bottom of the cylinder;

[0007] An impact head connected to the connecting end;

[0008] A stepped blind hole extending vertically upward is provided at the center of the end surface of the adjusting end, the stepped blind hole comprises an upper hole body with a smaller diameter located at the top and a lower hole body with a larger diameter located at the bottom, and a tapered hole body connecting the upper hole body and the lower hole body, the inner wall surface of the tapered hole body is a tapered surface with a larger upper opening and a smaller lower opening;

[0009] The outer circumferential surface of the piston rod is provided with an adjustment hole intersecting with the stepped blind hole, the adjustment hole comprises an upper adjustment hole and a lower adjustment hole, the upper adjustment hole is located above the tapered hole body and connects the upper sealing cavity and the upper hole body, the lower adjustment hole is located below the tapered hole body and connects the lower sealing cavity and the lower hole body;

[0010] The negative wave generator also includes an adjusting rod inserted into the stepped blind hole and threadedly connected thereto, and the upper end of the adjusting rod is provided with a mating surface matching the conical surface. When the adjusting rod is tightened, the mating surface is in contact with and pressed against the conical surface to isolate the upper hole body from the lower hole body. When the adjusting rod is loosened, the mating surface is disengaged from the conical surface to form a gap connecting the upper hole body and the lower hole body.

[0011] Preferably, the upper opening of the tapered hole body is lower than or flush with the upper end surface of the piston, and the lower opening of the tapered hole body is higher than or flush with the lower end surface of the piston.

[0012] Preferably, there are multiple upper adjustment holes and multiple lower adjustment holes, and the multiple upper adjustment holes and the multiple lower adjustment holes are evenly distributed around the axis of the piston rod, and the sum of the cross-sectional areas of all the upper adjustment holes is equal to the sum of the cross-sectional areas of all the lower adjustment holes.

[0013] Preferably, the upper adjustment hole is an inclined hole extending inwardly and downwardly, the opening of the upper adjustment hole on the outer circumferential surface of the piston rod is higher than the upper end surface of the piston, and the opening of the upper adjustment hole on the inner wall surface of the upper hole body is lower than the upper end surface of the piston; the lower adjustment hole is an inclined hole extending inwardly and upwardly, the opening of the lower adjustment hole on the outer circumferential surface of the piston rod is lower than the lower end surface of the piston, and the opening of the lower adjustment hole on the inner wall surface of the lower hole body is higher than the lower end surface of the piston.

[0014] Preferably, the outer circumferential surface of the adjusting rod is provided with a plurality of spaced annular sealing grooves, and an O-ring for sealing the outer circumferential surface of the adjusting rod and the inner wall surface of the lower hole body is provided in the annular sealing groove.

[0015] Preferably, a locking nut is threadedly connected to the lower end of the adjusting rod, and the locking nut presses upward against the end surface of the adjusting end.

[0016] Preferably, the cylinder comprises a hollow cylindrical body, an upper end cover sealedly connected to the upper end surface of the body, and a lower end cover connected to the lower end surface of the body, and the lower end cover is provided with an exhaust hole connecting the lower sealing cavity and the outside atmosphere.

[0017] Further preferably, the four sides of the lower end cover extend horizontally outward to form a skirt, the upper surface of the lower end cover is connected to a buffer pad, the buffer pad is annular and coaxially sleeved on the piston rod, and the lower end cover is integrally formed with the cylinder.

[0018] Preferably, the piston and the piston rod are integrally formed, and the diameter of the piston rod located below the piston is greater than the diameter of the piston rod located above the piston.

[0019] Preferably, the support frame includes a support rod and a support plate, the upper end of the support rod is connected to the bottom of the cylinder barrel, the lower end of the support rod is connected to the support plate, and the center of the support plate is provided with an avoidance hole for avoiding the adjustment end.

[0020] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0021] The negative wave generating device provided by the present invention comprises a negative wave generator having a cylinder, a piston, and a piston rod, a support frame supported at the bottom of the cylinder, and an impact head connected to the connecting end of the piston rod penetrating the cylinder and extending upward, the piston rod is coaxially penetrated on the piston, and the lower end portion thereof penetrates the cylinder and extends downward to form an adjusting end; a stepped blind hole is provided at the center of the end face of the adjusting end, so that it comprises an upper hole body with a smaller diameter and a lower hole body with a larger diameter, and a tapered hole body connecting the upper hole body and the lower hole body, an upper adjusting hole and a The lower adjusting hole is located below the tapered hole body and connects the lower sealing cavity and the lower hole body. An adjusting rod is inserted in the stepped blind hole and threadedly connected, so that the upper end of the adjusting rod has a mating surface that matches the tapered surface of the tapered hole body. When the adjusting rod is tightened, the upper hole body and the lower hole body can be isolated by the fit and tightness of the mating surface and the tapered surface. When the adjusting rod is loosened, a gap connecting the upper hole body and the lower hole body can be formed by the separation of the mating surface and the tapered surface, thereby changing the equilibrium time of the pressure in the upper and lower sealing cavities, thereby realizing the adjustment of the negative pulse wave, which is not affected by the axial rotation of the piston and is suitable for high-precision double-wave impact tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic front view of a preferred embodiment of the present invention, with a partial cross-section.

[0023] Figure 2 yes Figure 1 A local enlarged schematic diagram of point A in the middle.

[0024] Figure 3 yes Figure 1 An enlarged schematic diagram of the front view of the middle adjustment lever.

[0025] Among them: 10. Negative wave generator; 11. Cylinder; 111. Upper sealing chamber; 112. Lower sealing chamber; 113. Cylinder body; 114. Upper end cover; 115. Lower end cover; 1151. Skirt; 116. Exhaust hole; 1161. Horizontal blind hole; 1162. Vertical blind hole; 117. Buffer pad; 12. Piston; 121. Annular groove; 122. O-ring; 13. Piston rod; 131. Connecting end; 132. Adjusting end; 1321. Upper hole body; 1322. Lower hole body; 1323. Conical hole body; 1331. Upper adjusting hole; 1332. Lower adjusting hole; 14. Adjusting rod; 141. Matching surface; 142. Annular sealing groove; 143. O-ring; 144. Locking nut; 20. Support frame; 21. Support rod; 22. Support plate; 221. Avoidance hole; 30. Impact head. DETAILED DESCRIPTION

[0026] The up and down directions described in the present invention are Figure 1 The up and down directions in .

[0027] like Figures 1 to 3 As shown, the negative wave generating device provided by the present invention comprises a negative wave generator 10, a support frame 20, and an impact head 30, wherein the negative wave generator 10 comprises a cylinder 11, a piston 12, and a piston rod 13, wherein a sealed cavity is provided in the cylinder 11, and the piston 12 is arranged in the sealed cavity so as to be movable up and down, and the outer circumferential surface of the piston 12 is dynamically sealedly connected with the inner wall surface of the sealed cavity (the dynamic sealing connection is realized by an annular groove 121 provided on the outer circumferential surface of the piston 12 and an O-ring 122 arranged in the annular groove 121), and the sealed cavity is divided into an upper sealed cavity 111 and a lower sealed cavity 112. 2. The piston rod 13 is coaxially arranged on the piston 12. The upper end of the piston rod 13 penetrates the cylinder 11 and extends upward to form a connecting end 131. The lower end of the piston rod 13 penetrates the cylinder 11 and extends downward to form an adjusting end 132. The support frame 20 is supported at the bottom of the cylinder 11. The impact head 30 is connected to the connecting end 131. A stepped blind hole extending vertically upward is opened at the center of the end surface of the adjusting end 132. The stepped blind hole includes an upper hole body 1321 with a smaller diameter located at the top and a lower hole body 1322 with a larger diameter located at the bottom, as well as a connecting hole 1321 and a lower hole body 1322. The conical hole body 1323, the inner wall surface of the conical hole body 1323 is a conical surface with a large upper opening and a small lower opening; the outer circumferential surface of the piston rod 13 is provided with an adjustment hole that intersects with the stepped blind hole, the adjustment hole includes an upper adjustment hole 1331 and a lower adjustment hole 1332, the upper adjustment hole 1331 is located above the conical hole body 1323 and connects the upper sealing cavity 111 and the upper hole body 1321, the lower adjustment hole 1332 is located below the conical hole body 1323 and connects the lower sealing cavity 112 and the lower hole body 1322; the negative wave generator 10 also includes an adjustment rod 14 inserted in the stepped blind hole and threadedly connected thereto, The upper end of the adjusting rod 14 is provided with a mating surface 141 that matches the conical surface of the conical hole body 1323. When the adjusting rod 14 is tightened, the mating surface 141 and the conical surface of the conical hole body 1323 are in contact and pressed against each other to form a mechanical seal, thereby isolating the upper hole body 1321 and the lower hole body 1322, thereby separating the upper sealing cavity 111 from the lower sealing cavity 112. When the adjusting rod 14 is loosened, the mating surface 141 is separated from the conical surface of the conical hole body 1323, and a gap connecting the upper hole body 1321 and the lower hole body 1322 is formed, thereby connecting the upper sealing cavity 111 and the lower sealing cavity 112.

[0028] The advantage of this arrangement is that, by loosening the adjusting rod, the gap formed by the separation between the mating surface and the tapered surface of the tapered hole body can be used to connect the upper hole body and the lower hole body, and then connect the upper sealing chamber and the lower sealing chamber, thereby changing the equilibrium time of the pressure in the upper sealing chamber and the lower sealing chamber, and realizing the adjustment of the negative pulse wave. By adjusting the degree of loosening of the adjusting rod, the size of the gap can also be controlled, and the equilibrium time of the pressure in the upper sealing chamber and the lower sealing chamber can be controlled. In actual use, it is not affected by the axial rotation of the piston, and will not cause wear to the upper adjusting hole and the lower adjusting hole. It is suitable for high-precision double-wave impact tests, and the requirements for component processing accuracy are relatively low, which can greatly reduce the manufacturing cost of the negative wave generating device.

[0029] In this embodiment, the conical hole body 1323 is arranged correspondingly to the piston 12 , which means that the upper opening of the conical hole body 1323 is lower than the upper end surface of the piston 12 , and the lower opening of the conical hole body 1323 is higher than the lower end surface of the piston 12 .

[0030] In order to ensure the balance of intake and exhaust and eliminate the radial force on the piston 12 and the piston rod 13, there are preferably multiple upper adjustment holes 1331 and lower adjustment holes 1332, and the multiple upper adjustment holes 1331 and the multiple lower adjustment holes 1332 are evenly distributed around the axis of the piston rod 13. Furthermore, the sum of the cross-sectional areas of all the upper adjustment holes 1331 is equal to the sum of the cross-sectional areas of all the lower adjustment holes 1332. For the convenience of processing, the number and aperture of the upper adjustment holes 1331 and the lower adjustment holes 1332 are equal; specifically, in this embodiment, there are two upper adjustment holes 1331 and two lower adjustment holes 1332, and the axis lines of the two upper adjustment holes 1331 are located in the same plane, and the plane also passes through the axis lines of the two lower adjustment holes 1332.

[0031] In order to improve the smoothness of gas inlet and outlet, in this embodiment, the upper adjustment hole 1331 is an inclined hole extending inwardly and downwardly, the opening of the upper adjustment hole 1331 on the outer circumferential surface of the piston rod 13 is higher than the upper end surface of the piston 12, and the opening of the upper adjustment hole 1331 on the inner wall surface of the upper hole body 1321 is lower than the upper end surface of the piston 12; the lower adjustment hole 1332 is an inclined hole extending inwardly and upwardly, the opening of the lower adjustment hole 1332 on the outer circumferential surface of the piston rod 13 is lower than the lower end surface of the piston 12, and the lower adjustment hole 133 The opening on the inner wall of the lower hole body 1322 is higher than the lower end surface of the piston 12; the inclination angles of the upper adjustment hole 1331 and the lower adjustment hole 1332 are preferably 60-80°, and at the same time, the inclination angles of the upper adjustment hole 1331 and the lower adjustment hole 1332 are equal; further, the opening of the upper adjustment hole 1331 on the outer circumferential surface of the piston rod 13 is 3-6 mm higher than the upper end surface of the piston 12, and the opening of the lower adjustment hole 1332 on the outer circumferential surface of the piston rod 13 is 3-6 mm lower than the lower end surface of the piston 12.

[0032] To facilitate processing, in this embodiment, the lower opening of the conical hole body 1323 is located on the upper bottom surface of the lower hole body 1322, that is, the diameter of the lower opening of the conical hole body 1323 is smaller than the inner diameter of the lower hole body 1322. At the same time, the inclination angle of the conical surface of the conical hole body 1323 is 30°.

[0033] To ensure the sealing effect and facilitate adjustment, in the present embodiment, the outer circumferential surface of the adjusting rod 14 is provided with a plurality of annular sealing grooves 142 spaced apart in the upper and lower directions, and the annular sealing groove 142 is provided with an O-ring 143 for sealing the outer circumferential surface of the adjusting rod 14 and the inner wall surface of the lower hole body 1322, and the lower end portion of the adjusting rod 14 is threadedly connected with a locking nut 144, which presses upward against the end surface of the adjusting end 132.

[0034] To ensure the sealing effect and facilitate the processing of the stepped blind hole, in the present embodiment, the piston 12 and the piston rod 13 are integrally formed, and the diameter of the piston rod 13 below the piston 12 is greater than the diameter of the piston rod 13 above the piston 12. Specifically, the diameter of the piston rod 13 below the piston 12 is 1.1-1.5 times the diameter of the piston rod 13 above the piston 12.

[0035] In this embodiment, the cylinder 11 includes a hollow cylindrical barrel 113, an upper end cover 114 sealedly connected to the upper end surface of the barrel 113, and a lower end cover 115 connected to the lower end surface of the barrel 113. The lower end cover 115 is provided with an exhaust hole 116 connecting the lower sealed cavity 112 and the outside atmosphere. The exhaust hole 116 is L-shaped, and the exhaust hole 116 has a horizontal blind hole 1161 extending in the horizontal direction and a vertical blind hole 1162 vertically connected to the horizontal blind hole 1161. The horizontal blind hole 1161 is provided with a vertical blind hole 1162 extending in the horizontal direction and vertically connected to the horizontal blind hole 1161. The opening of 61 is located on the side wall of the lower end cover 115, and the opening of the vertical blind hole 1162 is located on the upper end surface of the lower end cover 115. Furthermore, a buffer pad 117 is connected to the upper surface of the lower end cover 115. The buffer pad 117 is annular and coaxially sleeved on the piston rod 13. The buffer pad 117 does not block the opening of the vertical blind hole 1162 located on the lower end cover 115. The surrounding areas of the lower end cover 115 also extend horizontally outward to form a skirt 1151. The lower end cover 115 and the cylinder body 113 are integrally formed.

[0036] In this embodiment, the support frame 20 includes a support rod 21 and a support plate 22. The upper end of the support rod 21 is connected to the bottom of the cylinder 11. Specifically, the upper end of the support rod 21 is connected to the skirt 1151, and the lower end of the support rod 21 is connected to the support plate 22. The center of the support plate 22 is provided with an avoidance hole 221 for avoiding the adjustment end 132.

[0037] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A negative wave generating device, comprising: A negative wave generator, the negative wave generator comprises a cylinder, a piston and a piston rod, the cylinder is provided with a sealed cavity, the piston is movably arranged in the sealed cavity, the outer circumferential surface of the piston is dynamically sealed with the inner wall surface of the sealed cavity, and the sealed cavity is divided into an upper sealed cavity and a lower sealed cavity, the piston rod is coaxially penetrated on the piston, the upper end of the piston rod passes through the cylinder and extends upward to form a connecting end, and the lower end of the piston rod passes through the cylinder and extends downward to form an adjusting end; A support frame, the support frame is supported on the bottom of the cylinder; An impact head connected to the connecting end; Features: A stepped blind hole extending vertically upward is provided at the center of the end surface of the adjusting end, the stepped blind hole comprises an upper hole body with a smaller diameter located at the top and a lower hole body with a larger diameter located at the bottom, and a tapered hole body connecting the upper hole body and the lower hole body, the inner wall surface of the tapered hole body is a tapered surface with a larger upper opening and a smaller lower opening; The outer circumferential surface of the piston rod is provided with an adjustment hole intersecting with the stepped blind hole, the adjustment hole comprises an upper adjustment hole and a lower adjustment hole, the upper adjustment hole is located above the tapered hole body and connects the upper sealing cavity and the upper hole body, the lower adjustment hole is located below the tapered hole body and connects the lower sealing cavity and the lower hole body; The negative wave generator also includes an adjusting rod inserted into the stepped blind hole and threadedly connected thereto, and the upper end of the adjusting rod is provided with a mating surface matching the conical surface. When the adjusting rod is tightened, the mating surface is in contact with and pressed against the conical surface to isolate the upper hole body from the lower hole body. When the adjusting rod is loosened, the mating surface is disengaged from the conical surface to form a gap connecting the upper hole body and the lower hole body.

2. The negative wave generating device according to claim 1, characterized in that: The upper opening of the tapered hole body is lower than or flush with the upper end surface of the piston, and the lower opening of the tapered hole body is higher than or flush with the lower end surface of the piston.

3. The negative wave generating device according to claim 1, characterized in that: There are multiple upper adjustment holes and multiple lower adjustment holes, and the multiple upper adjustment holes and the multiple lower adjustment holes are evenly distributed around the axis of the piston rod, and the sum of the cross-sectional areas of all the upper adjustment holes is equal to the sum of the cross-sectional areas of all the lower adjustment holes.

4. The negative wave generating device according to claim 1, characterized in that: The upper adjustment hole is an inclined hole extending inwardly and downwardly, and the opening of the upper adjustment hole on the outer circumferential surface of the piston rod is higher than the upper end surface of the piston, and the opening of the upper adjustment hole on the inner wall surface of the upper hole body is lower than the upper end surface of the piston; the lower adjustment hole is an inclined hole extending inwardly and upwardly, and the opening of the lower adjustment hole on the outer circumferential surface of the piston rod is lower than the lower end surface of the piston, and the opening of the lower adjustment hole on the inner wall surface of the lower hole body is higher than the lower end surface of the piston.

5. The negative wave generating device according to claim 1, characterized in that: The outer circumferential surface of the adjusting rod is provided with a plurality of annular sealing grooves spaced apart from each other, and an O-shaped sealing ring for sealing the outer circumferential surface of the adjusting rod and the inner wall surface of the lower hole body is arranged in the annular sealing groove.

6. The negative wave generating device according to claim 1, characterized in that: The lower end of the adjusting rod is threadedly connected with a locking nut, and the locking nut presses upward against the end surface of the adjusting end.

7. The negative wave generating device according to claim 1, characterized in that: The cylinder comprises a hollow cylindrical body, an upper end cover sealedly connected to the upper end surface of the body, and a lower end cover connected to the lower end surface of the body. The lower end cover is provided with an exhaust hole connecting the lower sealing cavity and the outside atmosphere.

8. The negative wave generating device according to claim 7, characterized in that: The lower end cover is horizontally extended outward around to form a skirt, and the upper surface of the lower end cover is connected with a buffer pad, which is annular and coaxially sleeved on the piston rod, and the lower end cover is integrally formed with the cylinder.

9. The negative wave generating device according to claim 1, characterized in that: The piston and the piston rod are integrally formed, and the diameter of the piston rod located below the piston is greater than the diameter of the piston rod located above the piston.

10. The negative wave generating device according to claim 1, characterized in that: The support frame includes a support rod and a support plate, the upper end of the support rod is connected to the bottom of the cylinder barrel, the lower end of the support rod is connected to the support plate, and the center of the support plate is provided with an avoidance hole for avoiding the adjustment end.

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