Dual-channel magnetorheological damper with asymmetric damping characteristic

Abstract

The utility model discloses a dual-channel asymmetric damping characteristic magneto-rheological damper which comprises a magneto-rheological damper body, and the magneto-rheological damper body comprises a working cylinder and a piston assembly which is arranged in the working cylinder and divides the working cylinder into an upper cavity and a lower cavity. A first damping channel and a second damping channel which are used for communicating the upper cavity with the lower cavity are arranged in the magnetorheological damper body; the piston assembly comprises a piston sleeve arranged in the working cylinder in a sliding mode and a piston core coaxially and fixedly arranged in the piston sleeve, and the first damping channel comprises a first annular channel formed between the outer circumferential face of the piston sleeve and the inner circumferential face of the working cylinder. The second damping channel comprises a second annular channel formed between the outer circumferential face of the piston core and the inner circumferential face of the piston sleeve. According to the dual-channel magnetorheological damper with the asymmetric damping characteristic, the production cost of a product can be reduced, and therefore field application and popularization can be facilitated; and meanwhile, the regulation and control range of the asymmetric damping characteristic in a limited arrangement space can be improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of vibration suppression relates to a kind of double-channel asymmetric damping characteristic magneto-rheological damper. BACKGROUND

[0002] The asymmetric damping characteristic magneto-rheological damper is an intelligent damping device designed based on the controllable rheological characteristics of magneto-rheological fluid. Its core is to adjust the damping force through the magnetic field to present differential response in compression and recovery stage, which can meet the dynamic control requirements under complex conditions. Among them, the double-flow design scheme controls the liquid flow path of the magneto-rheological damper in compression and recovery stage independently, and combines with magnetic field partition adjustment, which is an important technical path to realize asymmetric damping characteristics. However, the existing double-flow magneto-rheological damper structure is mainly based on the scheme of distributing fine fluid passage holes around the center hole of the iron core, which has the problems of complex structure, high processing precision requirement and high processing difficulty, resulting in high overall cost, which is not conducive to market promotion and application. Moreover, in the case of limited size design space of the magneto-rheological damper, the adjustable range of asymmetric damping characteristics is small, which is difficult to meet the scene application requirements of limited size design space of the magneto-rheological damper.

[0003] Therefore, how to improve the structure of the existing double-channel asymmetric damping characteristic magneto-rheological damper for the purpose of reducing the production cost of the product, so as to facilitate the market promotion and application, and at the same time, improve the adjustable range of asymmetric damping characteristics in limited arrangement space. UTILITY MODEL CONTENT

[0004] Therefore, the utility model provides a kind of double-channel asymmetric damping characteristic magneto-rheological damper, which can reduce the production cost of product, so as to facilitate the market promotion and application, and at the same time, improve the adjustable range of asymmetric damping characteristics in limited arrangement space.

[0005] To achieve the above purpose, the utility model provides the following technical scheme: a kind of double-channel asymmetric damping characteristic magneto-rheological damper, including magneto-rheological damper body, the magneto-rheological damper body includes working cylinder and the piston assembly being set in working cylinder and separating working cylinder into upper cavity and lower cavity, first damping channel and second damping channel for communicating upper cavity and lower cavity are equipped in the magneto-rheological damper body;

[0006] The piston assembly includes a piston sleeve slidingly arranged in the working cylinder and a piston core body coaxially fixed in the piston sleeve, the first damping channel includes a first annular channel formed between the outer peripheral surface of the piston sleeve and the inner peripheral surface of the working cylinder, and the second damping channel includes a second annular channel formed between the outer peripheral surface of the piston core body and the inner peripheral surface of the piston sleeve.

[0007] Further, the first damping passage is provided with a first normally closed valve assembly which is opened by the MR fluid flowing from the lower chamber to the upper chamber, and the second damping passage is a normally open passage and is provided with a second normally closed valve assembly which is opened by the MR fluid flowing from the upper chamber to the lower chamber.

[0008] Further, the end of the piston sleeve is provided with a radially outwardly protruding annular positioning boss which is slidingly and sealingly fitted in the inner cavity of the working cylinder;

[0009] The first damping passage further comprises a first communication hole which is arranged on the annular positioning boss and which communicates the first annular passage with the upper chamber.

[0010] Further, the piston assembly further comprises an upper end plate and a lower end plate which are respectively fixed to the upper end and the lower end of the piston sleeve, and the upper end and the lower end of the piston core body are respectively abutted against the upper end plate and the lower end plate.

[0011] The second damping passage further comprises a second communication hole which is arranged on the lower end plate and which communicates the second annular passage with the lower chamber, and a third communication hole which is arranged on the upper end plate and which communicates the second annular passage with the upper chamber.

[0012] Further, the upper end surface of the lower end plate is provided with a radial limiting hole for radially limiting the piston core body, and the lower end of the piston core body is installed in the radial limiting hole.

[0013] Further, the MR damper body further comprises a piston rod which is connected with the piston assembly and which can drive the piston assembly to reciprocate.

[0014] The upper end surface of the upper end plate is provided with an upwardly protruding first guide boss, and the piston rod axially penetrates the first guide boss and the upper end plate and is fixedly connected with the piston core body.

[0015] Further, the first normally closed valve assembly comprises a first annular valve plate which is axially slidingly arranged on the first guide boss, and a first return spring which makes the first annular valve plate abut against the annular positioning boss in the restoring stroke of the piston assembly, and the first annular valve plate is provided with a fourth communication hole which is aligned with the port of the third communication hole; when the first annular valve plate is closed, the first annular valve plate closes the first communication hole.

[0016] Further, the lower end surface of the lower end plate is provided with a downwardly protruding second guide boss.

[0017] The second normally closed valve assembly comprises a second annular valve disc axially slidably arranged on a second guide boss, a spring seat fixed to the lower end of the second guide boss, and a second return spring arranged between the spring seat and the second annular valve disc, the second annular valve disc is provided with a throttling hole, and the second annular valve disc partially blocks the second communication hole when the second annular valve disc is completely closed.

[0018] Further, the lower end of the piston sleeve is provided with a positioning step hole, and the lower end plate is fixedly arranged in the positioning step hole.

[0019] The upper end of the piston sleeve is provided with an annular limiting boss protruding radially inward, and the upper end of the upper end plate abuts against the annular limiting boss.

[0020] Further, the piston core is provided with two groups of excitation coils, and the winding directions of the two groups of excitation coils are opposite.

[0021] Compared with the prior art, the utility model has the beneficial effects as follows:

[0022] The double-channel asymmetric damping characteristic magneto-rheological damper can reduce the production cost of the product, and can be popularized and applied, and can improve the regulation range of the asymmetric damping characteristic in the limited arrangement space.

[0023] Other advantages, objects, and features of the present utility model will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following specification or can be learned by the practice of the present utility model. The objects and other advantages of the present utility model can be realized and obtained by means of the description which follows. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a cross-sectional structure schematic view of an embodiment of the utility model;

[0025] Figure 2 is Figure 1 is a partial enlarged view at A in the middle;

[0026] Figure 3 is Figure 1 is a partial enlarged view at B in the middle;

[0027] Figure 4 is an axial sectional view of the lower end plate of an embodiment of the utility model;

[0028] Figure 5 is an axial sectional view of the upper end plate of an embodiment of the utility model;

[0029] Figure 6 is an axial sectional view of the piston sleeve of an embodiment of the utility model;

[0030] Figure 7 is an axial structure schematic view of the overall structure of an embodiment of the utility model;

[0031] Figure 8 is a damper indicator diagram of the piston assembly at different speeds when the active control current is 0A;

[0032] Figure 9 is a damper indicator diagram of the piston assembly at different speeds when the active control current is 0.2A;

[0033] Fig. 1 - working cylinder; 101 - upper cavity; 102 - lower cavity; 2 - piston rod; 3 - piston assembly; 3a - first damping channel; 3b - second damping channel; 301 - piston sleeve; 301a - first annular channel; 3011 - annular positioning boss; 3011a - first communication hole; 3012 - positioning step hole; 3013 - annular limiting boss; 302 - piston core; 302a - second annular channel; 302b - excitation coil mounting groove; 303 - excitation coil; 304 - upper end plate; 304a - third communication hole; 304b - first guide boss; 305 - lower end plate; 305a - second communication hole; 305b - radial limiting hole; 305c - second guide boss; 4 - first normally closed valve assembly; 401 - first annular valve plate; 401a - fourth communication hole; 402 - first return spring; 5 - second normally closed valve assembly; 501 - second annular valve plate; 501a - throttling hole; 502 - spring seat; 503 - second return spring; 6 - protective sleeve; 7 - lifting lug. DETAILED DESCRIPTION

[0034] The embodiments of the present application will be described in detail with specific examples. Those skilled in the art can easily understand other advantages and functions of the present application from the content disclosed in the specification. The present application can also be implemented or applied through different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the drawings provided in the following examples are only used to illustrate the basic concept of the present application, and the features in the following examples and embodiments can be combined with each other without conflict.

[0035] Please refer to Figures 1-7 In the embodiment, a double-channel asymmetric damping characteristic magneto-rheological damper is disclosed, which comprises a magneto-rheological damper body, the magneto-rheological damper body comprises a working cylinder 1 and a piston assembly 3 arranged in the working cylinder 1 and separating the working cylinder 1 into an upper cavity 101 and a lower cavity 102, and the magneto-rheological damper body is provided with a first damping channel 3a and a second damping channel 3b for connecting the upper cavity 101 and the lower cavity 102; the piston assembly 3 comprises a piston sleeve 301 slidingly arranged in the working cylinder 1 and a piston core 302 coaxially and fixedly arranged in the piston sleeve 301, the first damping channel 3a comprises a first annular channel 301a formed between the outer circumferential surface of the piston sleeve 301 and the inner circumferential surface of the working cylinder 1, and the second damping channel 3b comprises a second annular channel 302a formed between the outer circumferential surface of the piston core 302 and the inner circumferential surface of the piston sleeve 301. Here, "upper" and "lower" in the upper cavity 101 and the lower cavity 102 are based on the up-down direction in the drawing. Figure 1 It can be understood that the magneto-rheological fluid is arranged in the working cylinder 1, and the process of the magneto-rheological fluid from the lower cavity 102 to the upper cavity 101 corresponds to the compression stroke of the damper downward, and the process of the magneto-rheological fluid from the upper cavity 101 to the lower cavity 102 corresponds to the recovery stroke of the damper upward. It can be understood that the magneto-rheological damper body further comprises a piston rod 2 connected with the piston assembly 3 and capable of driving the piston assembly 3 to reciprocate; the piston core 302 is usually a cylindrical iron core, and an excitation coil 303 is arranged on the iron core to generate a magnetic field to realize active adjustment of the damping characteristic of the magneto-rheological fluid; in order to facilitate threading, threading holes are arranged on the iron core and the piston rod 2 along the central axis direction; in order to realize the asymmetry of the compression and recovery strokes of the damping characteristic of the magneto-rheological damper, a one-way control valve is usually arranged on one of the first damping channel 3a and the second damping channel 3b to realize the asymmetry of the compression and recovery strokes; these can be consistent with the structure of the existing double-channel asymmetric magneto-rheological damper, which is prior art, and will not be described here.

[0036] The double-channel asymmetric damping characteristic magnetorheological damper provided in the structure can facilitate the reduction of the production cost of the product, thereby facilitating the popularization and application; meanwhile, it can facilitate the improvement of the regulation range of the asymmetric damping characteristic under the limited arrangement space. Specifically, the double-channel asymmetric damping characteristic magnetorheological damper provided in the embodiment improves the structure of the main part of the two damping channels; wherein the first damping channel 3a comprises a first annular channel 301a formed between the outer circumferential surface of the piston sleeve 301 and the inner circumferential surface of the working cylinder 1, and the second damping channel 3b comprises a second annular channel 302a formed between the outer circumferential surface of the piston core 302 and the inner circumferential surface of the piston sleeve 301; the double-damping channel structure in the structure design avoids the direct opening of the elongated damping channel hole on the piston core 302, effectively reduces the processing difficulty, reduces the requirement for the processing precision, and can facilitate the reduction of the production cost of the product; meanwhile, under the condition of the limited arrangement space, the structure form of the annular channel is adopted, the opening and closing of one of the annular channels are controlled, the larger channel area change under the compression and recovery stroke can be realized, thereby facilitating the improvement of the difference value of the damping characteristic under the compression and recovery, that is, the regulation range of the asymmetric damping characteristic is improved.

[0037] In this embodiment, the first damping channel 3a is provided with a first normally closed valve assembly 4 which can be opened under the action of the magnetorheological fluid from the lower cavity 102 to the upper cavity 101, and the second damping channel 3b is a normally open channel and is provided with a second normally closed valve assembly 5 which can be opened under the action of the magnetorheological fluid from the upper cavity 101 to the lower cavity 102. It can be understood that in the compression stroke, the first normally closed valve assembly 4 is opened, the first damping channel 3a and the normally open second damping channel 3b work in double channels, providing small damping; in the recovery stroke, the first normally closed valve assembly 4 is closed, the normally open second damping channel 3b works in single channel, providing large damping. Due to the provision of the second normally closed valve assembly 5, it can be kept closed at low speed, improving the adjustable upper limit value of the damping force at low speed, and opened at high speed, reducing the adjustable lower limit value of the damping force at high speed. Compared with the traditional single-valve-controlled magnetorheological damper structure, in this structure design, by using the first normally closed valve assembly 4 and the second normally closed valve assembly 5 to control the first damping channel 3a and the second damping channel 3b respectively, the damping force in the recovery and compression process can be independently controlled by the corresponding valve assembly passively under the action of the magnetorheological fluid, which is simple in structure and easy to simplify the difficulty of the active control system, thereby facilitating further reducing the production cost; and due to the provision of the second normally closed valve assembly 5, the increase of the adjustable upper limit value of the damping force at low speed and the decrease of the adjustable lower limit value of the damping force at high speed in the recovery stroke can be realized, which effectively widens the damping force adjustment range of the damper at different speeds, i.e. in the same size design space, it is beneficial to further improve the adjustable range of the damping characteristics of the magnetorheological damper, and it is beneficial to better meet the scene application requirements of the size design space limitation of the magnetorheological damper. In addition, since the first normally closed valve assembly 4 is used to control the first damping channel 3a, the first annular channel 301a is located radially outside the second annular channel 302a in space, so that under the same radial size, the opening and closing of the first damping channel 3a can make the damping characteristics of the damper in the compression stroke and the recovery stroke more different, i.e. it is beneficial to further improve the adjustment range of the damping force in the limited space, and it is more beneficial to meet the scene application requirements of the size design space limitation of the magnetorheological damper, so that the overall axial and radial size can be more compact.

[0038] In the embodiment, the end of the piston sleeve 301 is provided with a radially outwardly protruding annular positioning boss 3011 which is slidingly and sealingly fitted in the inner cavity of the working cylinder 1; the first damping channel 3a further comprises a first communication hole 3011a provided on the annular positioning boss 3011 to communicate the first annular channel 301a with the upper cavity 101. Specifically, the annular positioning boss 3011 is located at the upper end of the piston sleeve 301, and an annular sealing groove is provided on the outer circumferential surface of the annular positioning boss 3011 to achieve dynamic sealing with the inner cavity wall of the working cylinder 1. The first communication hole 3011a is circumferentially and uniformly arranged as a plurality of holes. The annular positioning boss 3011 integrally arranged on the piston sleeve 301 can not only guide the movement of the piston sleeve 301, but also facilitate the formation of the first annular channel 301a, thus simplifying the structure of the first damping channel 3a, facilitating the machining of the first damping channel 3a, reducing the machining precision requirement of the first damping channel 3a, thereby facilitating further reduction of the production cost of the damper and facilitating market promotion and application. At the same time, without additional movement guiding structure, the overall axial size is small, which is beneficial to ensure that the piston assembly 3 has sufficient movement stroke in the limited length space.

[0039] In the embodiment, the piston assembly 3 further comprises an upper end plate 304 and a lower end plate 305 respectively corresponding to the upper and lower ends of the piston sleeve 301, and the upper and lower ends of the piston core 302 respectively abut against the upper end plate 304 and the lower end plate 305; the second damping channel 3b further comprises a second communication hole 305a provided on the lower end plate 305 to communicate the second annular channel 302a with the lower cavity 102, and a third communication hole 304a provided on the upper end plate 304 to communicate the second annular channel 302a with the upper cavity 101. The upper end plate 304 and the lower end plate 305 are both magnetic isolation plates to form a better magnetic field environment. The second communication hole 305a is axially arranged as a straight-through hole, and the third communication hole 304a is obliquely arranged as an inclined hole with respect to its own axis. The provision of the upper end plate 304 and the lower end plate 305 can facilitate the assembly limiting of the piston core 302, and ensure the installation stability and assembly convenience of the piston core 302. The provision of the second communication hole 305a and the third communication hole 304a can make the force value of the magnetorheological damper change more smoothly without sudden change.

[0040] In the embodiment, the upper end surface of the lower end plate 305 is provided with a radial limiting hole 305b for limiting the radial position of the piston core 302, and the lower end of the piston core 302 is installed in the radial limiting hole 305b. By providing the radial limiting hole 305b on the lower end plate 305, the assembly precision of the piston core 302 is facilitated to be ensured, and the product quality is improved.

[0041] In the embodiment, the magnetorheological damper body further comprises a piston rod 2 connected with the piston assembly 3 and capable of driving the piston assembly 3 to reciprocate, the upper end surface of the upper end plate 304 is provided with a first guide boss 304b protruding upward, and the piston rod 2 is axially penetrated through the first guide boss 304b and the upper end plate 304 and then fixedly connected with the piston core 302. By providing the first guide boss 304b, the piston rod 2 can be guided and the strength can be enhanced, so as to reduce the working shaking problem caused by the too large ratio of the shaft length to the shaft diameter.

[0042] In the embodiment, the first normally closed valve assembly 4 comprises a first annular valve plate 401 axially slidably arranged on the first guide boss 304b, and a first return spring 402 for abutting the annular positioning boss 3011 in the recovery stroke of the piston assembly 3, the first annular valve plate 401 is provided with a fourth communication hole 401a aligned with the port of the third communication hole 304a, and the first annular valve plate 401a closes the first communication hole 3011a when the first annular valve plate 401a is closed. Specifically, the first annular valve plate 401 is movably sleeved on the first guide boss 304b, the first return spring 402 is a tower spring, i.e. a conical spring, and has a large compression amount. The first guide boss 304b is provided with a tower spring mounting groove, the small end of the tower spring is clamped in the tower spring mounting groove, and the large end of the tower spring is pressed on the first annular valve plate 401. The fourth communication hole 401a can ensure that the second damping channel 3b is in a normally open state. The first normally closed valve assembly 4 in the structure design is simple and reliable, and is beneficial to cost control.

[0043] In the embodiment, the lower end surface of the lower end plate 305 is provided with a second guide boss 305c protruding downward; the second normally closed valve assembly 5 includes a second annular valve disc 501 axially slidably arranged on the second guide boss 305c, a spring seat 502 fixedly arranged at the lower end of the second guide boss 305c, and a second return spring 503 arranged between the spring seat 502 and the second annular valve disc 501, the second annular valve disc 501 is provided with a throttling hole 501a, and when the second annular valve disc 501 is completely closed, the second annular valve disc 501 partially blocks the second communication hole 305a. Specifically, the second return spring 503 is a spiral compression spring. The throttling hole 501a is uniformly arranged as a plurality of throttling holes along the inner edge of the second annular valve disc 501. The outer diameter of the second annular valve disc 501 is smaller than the outer diameter of the lower end plate 305, and when closed, the second annular valve disc 501 partially blocks the second communication hole 305a in the radial direction, so that the second damping channel 3b can be in a normally open state. In the recovery stroke, when the piston assembly 3 moves upward at a low speed relative to the damper cylinder, the impact of the magnetorheological fluid on the second annular valve disc 501 is not enough to open the second annular valve disc 501, which increases the damping force of the damper at low speed and widens the upper limit value of the adjustable range of the damping force at low speed; when the piston assembly 3 moves upward at a high speed relative to the damper cylinder, the second annular valve disc 501 is opened under the impact of the magnetorheological fluid, the flow area is increased, the damping force of the damper at high speed is reduced, and the lower limit value of the adjustable range of the damping force at high speed is widened, thereby realizing the regulation and control of the damper force value under different speed conditions. The second normally closed valve assembly 5 in the structure design is simple and reliable, which is beneficial to cost control.

[0044] In the embodiment, the lower end of the piston sleeve 301 is provided with a positioning step hole 3012, and the lower end plate 305 is fixedly arranged in the positioning step hole 3012; the upper end of the piston sleeve 301 is provided with an annular limiting boss 3013 protruding radially inward, and the upper end of the upper end plate 304 abuts against the annular limiting boss 3013. Specifically, the lower end surface of the second guide boss 305c is flush with the lower end surface of the piston sleeve 301. By arranging the positioning step hole 3012 and the annular limiting boss 3013, stable and reliable installation of the lower end plate 305 and the upper end plate 304 is facilitated, assembly accuracy is ensured, product quality is improved, axial dimension can be saved, and piston stroke is ensured.

[0045] In this embodiment, the piston core 302 is provided with two sets of excitation coils 303, and the two sets of excitation coils 303 are wound in opposite directions; the piston core 302 is provided with an excitation coil mounting groove 302b, and the excitation coils 303 are arranged in the excitation coil mounting groove 302b. Specifically, the central axis of the piston core 302 is perforated to facilitate the threading of the excitation coils 303, and the top of the piston core 302 is threadedly connected to the piston rod 2. By setting two sets of excitation coils 303, two opposite magnetic fields are generated, and by setting the excitation coil mounting groove 302b, the structural compactness is ensured.

[0046] In this embodiment, a rigid protective sleeve 6 is provided on the outside of the working cylinder 1 to improve the durability of the damper; lifting lugs 7 are provided at the bottom of the working cylinder 1 and the top of the piston rod 2 to improve ease of use.

[0047] To facilitate a better understanding of the damping characteristics of the damper in this embodiment by those skilled in the art, the accompanying drawings are provided below. Figure 8 and attached Figure 9 The diagrams provided show the damper dynamometer of piston assembly 3 at different speeds when the active control current is 0A and 0.2A, respectively. Figure 8 and attached Figure 9 In the diagram, different colors correspond to different operating speeds of piston assembly 3. The area above the origin (positive direction of the force axis) corresponds to the return stroke of piston assembly 3, and the area below the origin (negative direction of the force axis) corresponds to the compression stroke of piston assembly 3. The origin of the displacement axis corresponds to the midpoint of the compression or return stroke of the piston assembly. (See attached diagram.) Figure 8 and attached Figure 9 It is clear that in this embodiment, the compression stroke damper provides small damping, while the recovery stroke provides large damping. At the same piston assembly 3 operating speed, the force exhibits significant asymmetric characteristics, especially after the active current is applied (e.g., changing from 0A to 0.2A). At the same positions in the recovery and compression strokes, the force values ​​show a greater difference. During the recovery stroke, the force values ​​vary considerably at different speeds, effectively broadening the control range of the damping force at different speeds.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A dual-channel asymmetrically damped characteristic magnetorheological damper, characterized in that: The magnetorheological damper body comprises a working cylinder (1) and a piston assembly (3) arranged in the working cylinder (1) and separating the working cylinder (1) into an upper cavity (101) and a lower cavity (102); a first damping channel (3a) and a second damping channel (3b) are arranged in the magnetorheological damper body for connecting the upper cavity (101) and the lower cavity (102); The piston assembly (3) comprises a piston sleeve (301) slidingly arranged in the working cylinder (1) and a piston core (302) coaxially arranged in the piston sleeve (301); the first damping channel (3a) comprises a first annular channel (301a) formed between the outer circumferential surface of the piston sleeve (301) and the inner circumferential surface of the working cylinder (1); and the second damping channel (3b) comprises a second annular channel (302a) formed between the outer circumferential surface of the piston core (302) and the inner circumferential surface of the piston sleeve (301).

2. The dual-channel asymmetrically damped characteristic magnetorheological damper of claim 1, wherein: The first damping channel (3a) is provided with a first normally closed valve assembly (4) which can be opened under the action of magnetorheological fluid from the lower cavity (102) to the upper cavity (101); and the second damping channel (3b) is a normally open channel and is provided with a second normally closed valve assembly (5) which can be opened under the action of magnetorheological fluid from the upper cavity (101) to the lower cavity (102).

3. The dual-channel asymmetrically damped MRF damper of claim 2, wherein: The end of the piston sleeve (301) is provided with a radially outwardly protruding annular positioning boss (3011) which is slidingly and sealingly arranged in the inner cavity of the working cylinder (1); The first damping channel (3a) further comprises a first communication hole (3011a) arranged on the annular positioning boss (3011) and connecting the first annular channel (301a) with the upper cavity (101).

4. The dual-channel asymmetrically damped MRF damper of claim 3, wherein: The piston assembly (3) further comprises an upper end plate (304) and a lower end plate (305) respectively arranged at the upper end and the lower end of the piston sleeve (301); and the upper end and the lower end of the piston core (302) respectively abut against the upper end plate (304) and the lower end plate (305). The second damping channel (3b) further comprises a second communication hole (305a) arranged on the lower end plate (305) and connecting the second annular channel (302a) with the lower cavity (102), and a third communication hole (304a) arranged on the upper end plate (304) and connecting the second annular channel (302a) with the upper cavity (101).

5. The dual-channel asymmetrically damped MRF damper of claim 4, wherein: The upper end surface of the lower end plate (305) is provided with a radial limiting hole (305b) for radially limiting the piston core (302); and the lower end of the piston core (302) is arranged in the radial limiting hole (305b).

6. The dual-channel asymmetrically damped MRF damper of claim 4, wherein: The magnetorheological damper body further comprises a piston rod (2) connected with the piston assembly (3) and capable of driving the piston assembly (3) to reciprocate. The upper end surface of the upper end plate (304) is provided with a first guide boss (304b) protruding upward; and the piston rod (2) is fixedly connected with the piston core (302) after axially penetrating through the first guide boss (304b) and the upper end plate (304).

7. The dual-channel asymmetrically damped MRF damper of claim 6, wherein: The first normally closed valve assembly (4) comprises a first annular valve plate (401) axially slidably arranged on a first guide boss (304b), and a first reset spring (402) for abutting the first annular valve plate (401) against the annular positioning boss (3011) in the recovery stroke of the piston assembly (3), the first annular valve plate (401) is provided with a fourth communication hole (401a) aligned with the port of the third communication hole (304a); when the first annular valve plate (401) is closed, the first annular valve plate (401) will close the first communication hole (3011a).

8. The dual-channel asymmetrically damped MRF damper of claim 4, wherein: The lower end surface of the lower end plate (305) is provided with a downwardly protruding second guide boss (305c); The second normally closed valve assembly (5) comprises a second annular valve plate (501) axially slidably arranged on the second guide boss (305c), a spring seat (502) fixedly arranged on the lower end of the second guide boss (305c), and a second reset spring (503) arranged between the spring seat (502) and the second annular valve plate (501), the second annular valve plate (501) is provided with a throttling hole (501a), and when the second annular valve plate (501) is completely closed, the second annular valve plate (501) will partially block the second communication hole (305a).

9. The dual-channel asymmetrically damped MRF damper of claim 8, wherein: The lower end of the piston sleeve (301) is provided with a positioning step hole (3012), and the lower end plate (305) is fixedly arranged in the positioning step hole (3012); The upper end of the piston sleeve (301) is provided with an annular limiting boss (3013) protruding radially inwardly, and the upper end of the upper end plate (304) abuts against the annular limiting boss (3013).

10. The dual-channel, asymmetrically damped characteristic magnetorheological damper of claim 2, wherein: The piston core (302) is provided with two groups of excitation coils (303), and the winding directions of the two groups of excitation coils (303) are opposite; the piston core (302) is provided with an excitation coil mounting groove (302b), and the excitation coils (303) are arranged in the excitation coil mounting groove (302b).

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