An independent piston controlled magnetorheological grease shock absorber

Abstract

The present application discloses an independent piston-controlled magnetorheological grease shock absorber, wherein the inner cylinder is arranged on the inner side of the outer cylinder, the upper guide seat is arranged at the upper end of the inner cylinder, and the lower base assembly is arranged at the lower end of the inner cylinder; an upper end cover is connected to the upper side of the outer cylinder, and a lower end cover is connected to the lower side of the outer cylinder; the rod sleeve is connected to the lower end cover by bolts, and the valve body mechanism is arranged inside the inner cylinder. When an external excitation causes the valve body mechanism to move, a pressure difference is formed, and the magnetorheological grease in the shock absorber flows; by controlling the input current of the piston coil in the lower base assembly or the valve body mechanism, the yield stress of the magnetorheological grease can be changed, thereby changing the flow pattern of the overall magnetorheological grease in the shock absorber and generating different damping forces. The present application uses magnetorheological grease as a matrix, which has a higher output damping force and is not easy to leak; the shock absorber has a larger dynamic range under the premise of keeping the maximum damping force unchanged. Compared with traditional pneumatic shock absorbers, the present application has a simple structure, is easy to assemble, and has higher stability.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetorheological intelligent material vibration reduction application, and in particular relates to an independent piston-controlled magnetorheological grease vibration damper. Background Art

[0002] With the continuous advancement of magnetorheological technology, semi-active control vibration reduction devices designed based on magnetorheological materials have become a hot topic of research for relevant institutions both domestically and internationally. These devices combine the advantages of both active and passive control, offering features such as continuously adjustable output damping force, fast response, low energy consumption, and ease of intelligent implementation. Currently, magnetorheological dampers are mostly made of magnetorheological fluid. Research has found that sedimentation, caused by the significant density difference between the ferromagnetic particles in the fluid and the base oil, has been a bottleneck restricting the development of magnetorheological dampers. Magnetorheological grease, however, uses grease as a continuous phase matrix, completely eliminating the sedimentation problem without affecting the magnetorheological response. Furthermore, magnetorheological grease has a higher yield strength and inherent consistency, eliminating the need for complex sealing mechanisms in device design and preventing leakage after repeated use. These advantages make it a significant advantage over traditional magnetorheological dampers and isolators in practical engineering applications.

[0003] However, the zero-field viscosity of magnetorheological grease is relatively high, which results in the current shock absorbers designed based on magnetorheological grease having a high passive viscous damping force in the zero-field condition and a small adjustable dynamic range. In order to apply magnetorheological shock absorbers to semi-active control systems such as automotive suspension, it is necessary to reduce the passive viscous damping force or increase the overall dynamic range. Summary of the Invention

[0004] The present invention aims to solve the defects of traditional magnetorheological grease shock absorbers, such as large viscous damping force and small dynamic range, and to provide an independent piston-controlled magnetorheological grease shock absorber.

[0005] In order to achieve the purpose of the present invention, the present invention discloses an independent piston-controlled magnetorheological grease shock absorber, which includes an inner cylinder, an outer cylinder, an upper guide seat, a lower base assembly, an upper end cover, a lower end cover, a rod sleeve and a valve body mechanism, and the shock absorber is filled with magnetorheological grease; the inner cylinder is arranged on the inner side of the outer cylinder, the upper guide seat is arranged at the upper end of the inner cylinder, and the lower base assembly is arranged at the lower end of the inner cylinder; the upper end cover is connected to the upper part of the outer cylinder, and the lower end cover is connected to the lower part of the outer cylinder; the rod sleeve and the lower end cover are connected by bolts, and the valve body mechanism is arranged inside the inner cylinder; when the external excitation causes the valve body mechanism to move, a hydraulic pressure difference is formed between the valve body mechanism and the upper and lower cavities of the inner cylinder, and the magnetorheological grease in the shock absorber flows; and by controlling the input current of the coil in the lower base assembly or the valve body mechanism, the yield stress of the magnetorheological grease can be changed, thereby changing the flow pattern of the overall magnetorheological grease in the shock absorber, thereby generating different damping forces.

[0006] Furthermore, the outer cylinder is connected to the upper end cover and the lower end cover by threads, and the size of the inner steps of the upper end cover and the lower end cover is the same as the size of the outer steps at both ends of the outer cylinder.

[0007] Furthermore, the lower base assembly includes a lower guide seat, a lower cover plate, a magnetic isolation sleeve and a base coil; the outer step size of the lower guide seat is the same as the inner step size of the bottom end of the outer cylinder; the lower cover plate is connected to the top of the lower guide seat by a thread, the magnetic isolation sleeve is fixed in the lower guide seat through the lower cover plate, and the base coil is wound on the magnetic isolation sleeve; the inner cylinder, the lower guide seat and the upper cover plate form a base damping gap, and by adjusting the current of the base coil, the yield strength of the magnetorheological grease in the base damping gap can be controlled.

[0008] Furthermore, the valve body mechanism includes a piston, an upper piston rod, a lower piston rod, and a piston coil; the piston coil is wound on the piston; the piston, the upper piston rod, and the lower piston rod are coaxially arranged and connected by threads, the upper piston rod is provided with an inner through hole, and the piston coil is led out from the inner through hole; a piston damping gap is formed between the outer surface of the piston and the inner wall of the inner cylinder, and by adjusting the current of the piston coil, the yield strength of the magnetorheological grease in the piston damping gap can be controlled.

[0009] Furthermore, when the shock absorber is in a compression or extension stroke, the movement of the valve body mechanism drives the magnetorheological grease in the lower cavity of the shock absorber to flow downward or upward; when current is passed through the piston coil, the magnetorheological grease cannot overcome the yield stress of the magnetorheological grease at the piston gap, and under the action of pressure, it only passes through the base damping gap, and flows into the annular channel between the inner cylinder and the outer cylinder from the liquid flow hole at the bottom end of the inner cylinder, and then flows into the upper cavity of the shock absorber through the liquid flow hole at the top end of the inner cylinder. The tensile flow direction is opposite to the compression flow direction; when current is passed through the base coil, the flowing magnetorheological grease cannot overcome the yield stress of the magnetorheological grease at the base damping gap, and under the action of pressure, it only passes through the piston damping gap.

[0010] Furthermore, a first groove having the same size as the top end of the inner cylinder is provided on the lower end surface of the upper guide seat; a second groove and a third groove are provided on the outer wall of the upper guide seat, and a fourth groove is provided on the inner wall, and sealing rings are respectively installed in the second groove, the third groove and the fourth groove; the outer step size of the upper guide seat is the same as the inner step size of the top end of the outer cylinder.

[0011] Furthermore, the outer wall of the lower guide seat is provided with a fifth groove and a sixth groove, and the inner wall is provided with a seventh groove, and sealing rings are installed in the fifth groove, the sixth groove and the seventh groove respectively; the upper end surface of the magnetic isolation sleeve is provided with an eighth groove of the same size as the bottom end of the inner cylinder, and a sealing ring is installed in the eighth groove.

[0012] Furthermore, liquid flow holes of the same size are provided at the upper and lower ends of the inner cylinder respectively; under the combined control of the lower base assembly and the valve body mechanism, the magnetorheological grease forms different flow patterns between the inner cylinder and the outer cylinder, thereby producing the expected damping effect.

[0013] Furthermore, the upper piston rod, the lower piston rod and the magnetic isolation sleeve are made of aluminum alloy; the inner cylinder, the outer cylinder, the upper guide seat, the lower guide seat, the lower cover plate, the upper end cover, the lower end cover, the rod sleeve and the piston are made of low carbon steel.

[0014] Furthermore, the contact surfaces of the base coil and the piston coil with the magnetorheological grease are made of epoxy resin to prevent coil corrosion and magnetic leakage.

[0015] The lower base assembly forms inner and outer base damping gaps between the lower base assembly and the bottom of the inner cylinder, while the piston damping gap forms a piston damping gap between the outer surface of the piston and the inner wall of the inner cylinder. The base coil and piston coil respectively control the yield strength of the magnetorheological grease in the base damping gap and piston damping gap. The movement of the valve body mechanism creates a pressure differential, driving the magnetorheological grease to flow. If the magnetorheological grease cannot overcome the yield strength of the magnetorheological grease in the piston damping gap (base damping gap), the magnetorheological grease in the piston damping gap (base damping gap) will be blocked and unable to flow. Based on this, the designed shock absorber has three flow modes. Mode 1 is similar to the traditional single-tube shear valve magnetorheological shock absorber, where the magnetorheological grease flows only through the piston damping gap; Mode 2 is similar to the traditional double-tube magnetorheological shock absorber, where the magnetorheological grease flows through the base damping gap and then circulates through the annular gap between the inner and outer cylinders; Mode 3, the magnetorheological grease flows through both the piston damping gap and the base damping gap. In mode three, the viscous damping force of the shock absorber is the lowest. By adjusting the two coils to achieve different flow patterns, the dynamic range of the output damping force can be improved.

[0016] Compared with the existing technology, the significant improvements of the present invention are: 1) The shock absorber described in the present invention uses magnetorheological grease as the matrix, has a higher output damping force, and is not easy to leak; 2) The shock absorber described in the present invention has a larger dynamic range under the premise of unchanged maximum damping force; 3) Compared with traditional pneumatic shock absorbers, the shock absorber described in the present invention has a simple structure, is easy to assemble, and has higher stability.

[0017] In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1This is a schematic diagram of the overall structure of the independent piston controlled magnetorheological grease shock absorber of the present invention;

[0020] Figure 2 Schematic diagram of the lower base assembly structure;

[0021] Figure 3 Schematic diagram of the valve body structure;

[0022] Figure 4 Schematic diagram of the flow pattern of an independent piston controlled magnetorheological grease shock absorber;

[0023] Figure 5 Schematic diagram of the relationship between the shock absorber working mode and input current;

[0024] The meanings of the numbers in the figure are: 1. Inner cylinder; 2. Outer cylinder; 3. Upper guide seat; 4. Lower base assembly; 5. Upper end cover; 6. Lower end cover; 7. Rod sleeve; 8. Valve body mechanism; 9. Magnetorheological grease; 31. First groove; 32. Second groove; 33. Third groove; 34. Fourth groove; 41. Lower guide seat; 42. Lower cover; 43. Magnetic isolation sleeve; 44. Base coil; 45. Base damping gap; 411. Fifth groove; 412. Sixth groove; 413. Seventh groove; 414. Eighth groove; 81. Piston; 82. Upper piston rod; 83. Lower piston rod; 84. Piston coil; 85. Piston damping gap. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the independent piston-controlled magnetorheological grease shock absorber of the present invention is a dual-rod, double-tube shock absorber, consisting of an inner cylinder 1, an outer cylinder 2, an upper guide seat 3, a lower base assembly 4, an upper end cap 5, a lower end cap 6, a rod sleeve 7, a valve mechanism 8, and magnetorheological grease 9. The upper guide seat 3 and the lower base assembly 4 are fixedly mounted to the ends of the inner cylinder 1 via grooves. The upper end cap 5 and the lower end cap 6 are threadedly connected to the outer cylinder 2, and the rod sleeve 7 is bolted to the lower end cap 6. The valve mechanism 8 is mounted within the inner cylinder 1 and can move along the cylinder axis. Grooves are provided on the inner and outer sides of the upper guide seat 3 and the lower base assembly 4 for mounting sealing rings, enabling both static and dynamic sealing.

[0027] like Figure 2As shown, the lower base assembly 4 consists of a lower guide seat 41, a lower cover plate 42, a magnetic isolation sleeve 43, and a base coil 44. The base coil 44 is wound around the magnetic isolation sleeve 43. The lower cover plate 42 is threadedly connected to the lower guide seat 41, securing the magnetic isolation sleeve 43 within the lower guide seat 41. The inner cylinder 1, the lower guide seat 41, and the lower cover plate 42 form a base damping gap 45. Adjusting the current flowing in the base coil 44 controls the yield strength of the magnetorheological grease 9 within the base damping gap 45.

[0028] like Figure 3 As shown, valve body mechanism 8 consists of a piston 81, an upper piston rod 82, a lower piston rod 83, and a piston coil 84. The upper and lower piston rods 82 and 83 are threadedly mounted on both ends of piston 81, and piston coil 84 is wound around piston 81. A piston damping gap 85 is formed between the outer surface of piston 81 and the inner wall of inner cylinder 1. Adjusting the current flowing in piston coil 84 controls the yield strength of the magnetorheological grease 9 within piston damping gap 85.

[0029] Combine Figure 1 、 Figure 4 and Figure 5 , the valve body mechanism 8 moves to form a pressure difference, driving the magnetorheological grease 9 to flow. If the magnetorheological grease cannot overcome the yield strength of the magnetorheological grease 9 in the piston damping gap 85 (base damping gap 45), the magnetorheological grease in the piston damping gap 85 (base damping gap 45) will be blocked and cannot flow. Based on this, if Figure 4 The shock absorber has three flow modes, and the switching of different modes can be achieved by controlling the input current of the base coil 44 and the piston coil 84 respectively. Figure 5 The figure shows the relationship between the operating mode and the input current. In Mode I, the current in the base coil 44 is substantially greater than that in the piston coil 84, and the magnetorheological grease 9 flows only through the piston damping gap 85. In Mode II, the current in the piston coil 84 is substantially greater than that in the base coil 44, and the magnetorheological grease 9 flows only through the base damping gap 45, then circulates through the flow holes at both ends of the inner cylinder 1 and the annular gap between the inner and outer cylinders. In Mode III, the currents in both coils are substantially the same, and the magnetorheological grease 9 flows through both the piston damping gap 85 and the base damping gap 45. In Mode III, the shock absorber's output viscous damping force is minimized. By controlling the two coils to achieve different flow patterns and damping force outputs, the dynamic range of the magnetorheological grease shock absorber is improved.

[0030] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An independent piston controlled magnetorheological grease shock absorber, characterized in that: The shock absorber comprises an inner cylinder (1), an outer cylinder (2), an upper guide seat (3), a lower base assembly (4), an upper end cover (5), a lower end cover (6), a rod sleeve (7) and a valve body mechanism (8), and the interior of the shock absorber is filled with magnetorheological grease (9); the inner cylinder (1) is arranged on the inner side of the outer cylinder (2), the upper guide seat (3) is arranged on the upper end of the inner cylinder (1), and the lower base assembly (4) is arranged on the lower end of the inner cylinder (1); the upper end cover (5) is connected to the upper side of the outer cylinder (2), and the lower end cover (6) is connected to the lower side of the outer cylinder (2). The rod sleeve (7) is connected to the lower end cover (6) by bolts, and the valve body mechanism (8) is arranged inside the inner cylinder (1); when the valve body mechanism (8) is moved by external excitation, a hydraulic pressure difference is formed between the valve body mechanism (8) and the upper and lower cavities of the inner cylinder (1), and the magnetorheological grease (9) in the shock absorber flows; and by controlling the input current of the coil in the lower base assembly (4) or the valve body mechanism (8), the yield stress of the magnetorheological grease (9) can be changed, thereby changing the flow pattern of the entire magnetorheological grease (9) in the shock absorber, thereby generating different damping forces; The outer cylinder (2) is connected to the upper end cover (5) and the lower end cover (6) by threads, and the inner step size of the upper end cover (5) and the lower end cover (6) is the same as the outer step size of the two ends of the outer cylinder (2); The lower base assembly (4) includes a lower guide seat (41), a lower cover plate (42), a magnetic isolation sleeve (43) and a base coil (44); the outer step size of the lower guide seat (41) is the same as the inner step size of the bottom end of the outer cylinder (2); the lower cover plate (42) is connected to the upper part of the lower guide seat (41) by screw thread, the magnetic isolation sleeve (43) is fixed in the lower guide seat (41) through the lower cover plate (42), and the base coil (44) is wound on the magnetic isolation sleeve (43); the inner cylinder (1), the lower guide seat (41) and the upper cover plate (42) form a base damping gap (45), and by regulating the current of the base coil (44), the yield strength of the magnetorheological grease (9) in the base damping gap (45) can be controlled; The valve body mechanism (8) includes a piston (81), an upper piston rod (82), a lower piston rod (83), and a piston coil (84); the piston coil (84) is wound on the piston (81); the piston (81), the upper piston rod (82), and the lower piston rod (83) are coaxially arranged and connected by threads, the upper piston rod (82) is provided with an inner through hole, and the piston coil (84) is led out from the inner through hole; a piston damping gap (85) is formed between the outer surface of the piston (81) and the inner wall of the inner cylinder (1), and the yield strength of the magnetorheological grease (9) in the piston damping gap (85) can be controlled by regulating the current of the piston coil (84); When the shock absorber is in a compression or extension stroke, the valve body mechanism (8) moves to drive the magnetorheological grease (9) in the lower cavity of the shock absorber to flow downward or upward; when current is passed through the piston coil (84), the magnetorheological grease (9) cannot overcome the yield stress of the magnetorheological grease (9) in the piston damping gap (85), and under the action of pressure, it only passes through the base damping gap (45), and flows into the annular channel between the inner cylinder (1) and the outer cylinder (2) through the liquid flow hole at the bottom end of the inner cylinder (1), and then flows into the upper cavity of the shock absorber through the liquid flow hole at the top end of the inner cylinder (1), and the tensile flow direction is opposite to the compression flow direction; when current is passed through the base coil (44), the flowing magnetorheological grease (9) cannot overcome the yield stress of the magnetorheological grease (9) in the base damping gap (45), and under the action of pressure, it only passes through the piston damping gap (85).

2. The independent piston controlled magnetorheological grease shock absorber according to claim 1, characterized in that: The lower end surface of the upper guide seat (3) is provided with a first groove (31) having the same size as the top end of the inner cylinder (1); a second groove (32) and a third groove (33) are provided on the outer wall of the upper guide seat (3), and a fourth groove (34) is provided on the inner wall; sealing rings are respectively installed in the second groove (32), the third groove (33) and the fourth groove (34); the outer step size of the upper guide seat (3) is the same as the inner step size of the top end of the outer cylinder (2).

3. The independent piston controlled magnetorheological grease shock absorber according to claim 1, characterized in that: The outer wall of the lower guide seat (41) is provided with a fifth groove (411) and a sixth groove (412), and the inner wall is provided with a seventh groove (413), and sealing rings are respectively installed in the fifth groove (411), the sixth groove (412) and the seventh groove (413); the upper end surface of the magnetic isolation sleeve (43) is provided with an eighth groove (414) of the same size as the bottom end of the inner cylinder (1), and a sealing ring is installed in the eighth groove (414).

4. The independent piston controlled magnetorheological grease shock absorber according to claim 1, characterized in that: The inner cylinder (1) is provided with six liquid flow holes of the same size at the upper and lower ends respectively; under the combined control of the lower base assembly (4) and the valve body mechanism (8), the magnetorheological grease (9) forms different flow patterns between the inner cylinder (1) and the outer cylinder (2), thereby producing the expected damping effect.

5. The independent piston controlled magnetorheological grease shock absorber according to claim 1, characterized in that: The upper piston rod (82), the lower piston rod (83) and the magnetic isolation sleeve (43) are made of aluminum alloy; the inner cylinder (1), the outer cylinder (2), the upper guide seat (3), the lower guide seat (41), the lower cover plate (42), the upper end cover (5), the lower end cover (6), the rod sleeve (7) and the piston (81) are made of low carbon steel.

6. The independent piston controlled magnetorheological grease shock absorber according to claim 1, characterized in that: The contact surfaces of the base coil (44) and the piston coil (84) with the magnetorheological grease (9) are made of epoxy resin to prevent coil corrosion and magnetic leakage.

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