Electromagnetic valve for variable damping shock absorber

Abstract

An electromagnetic valve for a variable damping shock absorber belongs to the technical field of variable damping shock absorbers and comprises a coil portion, a hydraulic portion and an electromagnetic portion connected between the coil portion and the hydraulic portion, the hydraulic portion comprises a hydraulic shell, a main valve component and a pilot valve component, and the main valve component and the pilot valve component are arranged in the hydraulic shell and communicated with each other. The pilot valve component has the advantages that the flow area of the pressure oil in a pilot valve cavity of the electromagnetic valve can be controlled more accurately, the risk of clamping stagnation caused by particulate matter is reduced, the service life of the pilot valve component is prolonged, and the service life of the pilot valve component is prolonged. And therefore, the shock absorber can provide more stable and reliable damping force in a safe working mode and a normal working mode.

Description

Technical Field

[0001] The utility model relates to the technical field of variable damping shock absorbers, in particular to a solenoid valve for a variable damping shock absorber. Background Art

[0002] In the existing technology, solenoid valve products include two parts: electromagnetic drive and hydraulic valve body. The hydraulic valve body includes a main valve part and a pilot part. The flow pressure and flow of the main valve are controlled by the pilot part. In the solenoid valve design, it is mentioned that when the solenoid valve is not energized, that is, the solenoid valve is working in a safe working mode, the pilot valve core is pressed against the stop surface close to the electromagnetic coil under the action of spring force and hydraulic pressure. The gap between the pilot valve core and the outer valve sleeve (hydraulic housing) forms an oil outlet flow channel. The size of this gap can determine the size of the shock absorber damping force value. Usually, by setting the size of the gap, the shock absorber damping is kept in an intermediate state, neither the hardest nor the softest.

[0003] For example, the patent with publication number CN112815033A proposes a solenoid valve for a variable damping shock absorber. In the safe working mode of the solenoid valve, the gap between the pilot valve core and the outer valve sleeve (hydraulic housing) forms an oil outlet flow channel. However, there are two problems in this design. First, the gap mentioned above is determined by two matching dimensions, one is the outer diameter of the pilot valve core, and the other is the inner diameter of the outer valve sleeve. Both parts are machined, and each part will inevitably have dimensional tolerances in the machining process. Usually, due to the limitations of the production and processing of parts, the gap tolerance cannot be controlled very accurately, which results in relatively large tolerances in mass production, which means that the damping force error of the shock absorber in the safe working mode is relatively large and the stability is poor. Second, in the design of the above-mentioned patent, the gap is the oil outlet flow section of the pilot valve cavity. Usually, the gap is less than 0.1mm. When the solenoid valve is not energized, the pressure oil in the pilot valve cavity will flow through the gap. However, due to processing reasons, the shock absorber components will inevitably produce metal and non-metallic impurities. When the oil flows through the gap area, the impurities in the oil are easily stuck in it, causing the operation of the pilot valve core to be obstructed, thereby affecting the damping function of the entire shock absorber. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a solenoid valve for a variable damping shock absorber. By designing the internal structure of the solenoid valve, the flow area of ​​the pressure oil in the pilot valve cavity of the solenoid valve can be more accurately controlled, while reducing the risk of jamming caused by particulate matter, thereby ensuring that the shock absorber can provide a more stable and reliable damping force in both the safe working mode and the normal working mode.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve its technical problems is: the solenoid valve for the variable damping shock absorber includes a coil part, a hydraulic part and an electromagnetic part connected therebetween; the hydraulic part includes a hydraulic housing and a main valve component and a pilot valve component connected thereto; the pilot valve component is provided with a central channel that allows the pressure oil to flow from the high-pressure area to the low-pressure area when the power is off.

[0006] The outer side of the electromagnetic part is interference-fitted with the coil part, and the inner side of the electromagnetic part is interference-fitted with the hydraulic part.

[0007] The pilot valve component includes a pilot valve seat fixed in the hydraulic housing, and the pilot valve seat divides the hydraulic housing into a pilot valve area and a main valve area that are connected;

[0008] A valve core stopper is fixed at one end of the pilot valve region, and a pilot valve core elastically connected to the pilot valve seat is provided between the valve core stopper and the pilot valve seat.

[0009] A connecting hole is provided in the middle of the pilot valve seat, a through hole is provided in the middle of the pilot valve core, a channel outlet is provided in the middle of the valve core stopper, and the connecting hole, the through hole and the channel outlet are connected to form the central channel.

[0010] The pilot valve core includes a valve core body, the through hole is provided at the center of the valve core body, and flow grooves for allowing pressure oil to pass through when power is supplied are provided at intervals on the outer circumference of the valve core body.

[0011] One side of the valve core body is provided with a contact plane that is in sealing contact with the armature push rod of the electromagnetic part when the power is on, and a sealing surface that is in sealing contact with the valve core stop when the power is off. The other side of the valve core body is provided with a sealing plane that is in sealing contact with the pilot valve seat when the power is on.

[0012] The sealing surface is configured as a conical surface, and the sealing surface is in sealing contact with a side line of the valve core stop.

[0013] The channel outlet includes an axial opening section and a flared section connected to each other, and the axial opening section is arranged close to the direction of the pilot valve core.

[0014] The pilot valve core is connected to the pilot valve seat through a pilot spring.

[0015] The main valve component includes a main valve seat fixed in the hydraulic housing at one end away from the coil portion and a main valve piston slidably connected to the middle of the hydraulic housing. The main valve piston is connected to the hydraulic housing through an elastic component.

[0016] The elastic component includes a preload spring positioned on the inner wall of the hydraulic housing and a main valve spring connected in series therewith, wherein one end of the main valve spring away from the preload spring is in contact with the main valve piston; the stiffness coefficient of the preload spring is smaller than the stiffness coefficient of the main valve spring.

[0017] The main valve seat and the hydraulic housing are connected to each other through an adjusting gasket.

[0018] An overflow hole is provided at the center of the main valve piston, an oil inlet hole is provided in the main valve seat, a plurality of oil outlets are provided at intervals along the circumference of the hydraulic housing, and a groove is provided on the outer side of the hydraulic housing near one end of the coil portion, and an L-shaped flow channel is formed between the groove and the electromagnetic portion;

[0019] A first oil channel is formed between the oil inlet hole, the oil outlet and the gap between the main valve piston and the main valve seat; a second oil channel is formed between the oil inlet hole, the overflow hole, the central channel and the L-shaped flow channel; a third oil channel is formed between the oil inlet hole, the overflow hole, the connecting hole in the center of the pilot valve seat, the gap between the pilot valve seat and the pilot valve core, the flow groove, the channel outlet in the middle of the valve core stop and the L-shaped flow channel.

[0020] A pilot valve cavity is formed between the hydraulic housing, the pilot valve core and the pilot valve seat; and a main valve cavity is formed between the hydraulic housing, the main valve piston and the pilot valve seat.

[0021] The electromagnetic part includes a threaded shell installed in the shock absorber mounting hole, the outer side of the threaded shell is interference fit with the coil part, the inner side of the threaded shell is interference fit with the hydraulic part, and a magnetic pole is fixed to one end of the threaded shell close to the coil part; the electromagnetic part also includes a magnetic pole bushing connected to the threaded shell, and an armature assembly guided through the magnetic pole is installed in the magnetic pole bushing, and one end of the armature assembly is connected to the magnetic pole through a return spring.

[0022] The beneficial effects of the utility model are:

[0023] This utility model provides a solenoid valve for a variable damping shock absorber. By providing a central channel in the pilot valve component through which pressurized oil passes when the power is off, the size of the central channel formed by the pilot valve component is easier to precisely control compared to the prior art method of creating a gap between the inner and outer diameters of two parts. This allows for tighter tolerances without the concern for larger gaps and leaks caused by eccentricity of the mating parts. Furthermore, when oil flows through this central channel, the aperture of the central channel can be set larger than the size of impurity particles, allowing them to flow directly through, significantly reducing the risk of the pilot valve core becoming stuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following is a brief description of the contents and marks in the drawings of the utility model specification:

[0025] Figure 1 This is a cross-sectional view of a solenoid valve for a variable damping shock absorber according to the present invention;

[0026] Figure 2 This is an exploded view of the solenoid valve for the variable damping shock absorber of the utility model;

[0027] Figure 3 It is a cross-sectional view of the electromagnetic part of the present utility model;

[0028] Figure 4 This is an exploded view of the hydraulic part of the utility model;

[0029] Figure 5 It is a cross-sectional view of the hydraulic part of the utility model;

[0030] Figure 6 for Figure 5 Axonometric drawing of the middle pilot valve core;

[0031] Figure 7 for Figure 6 sectional view of

[0032] Figure 8 for Figure 5 Axonometric drawing of the hydraulic housing;

[0033] Figure 9 This is a schematic diagram of the oil flow of the solenoid valve of the utility model in the power-off mode;

[0034] Figure 10 This is a schematic diagram of the force balance of the solenoid valve of the utility model in the power-on mode;

[0035] Figure 11 This is a schematic diagram of the oil flow of the solenoid valve of the utility model in the power-on mode;

[0036] The marks in the above figure are: 1. Coil part, 2. Electromagnetic part, 21. Threaded housing, 22. Magnetic pole, 23. Magnetic pole bushing, 24. Armature assembly, 241. Armature body, 242. Armature push rod, 25. Return spring, 3. Hydraulic part, 31. Hydraulic housing, 311. Oil outlet, 312. Groove, 313. L-shaped flow channel, 32. Main valve component, 321. Main valve seat, 3211. Oil inlet hole, 322. Main valve piston, 3221. Overflow hole, 323. Preload spring, 324. Main valve spring, 3 25. Adjusting gasket, 326. Main valve cavity, 33. Pilot valve component, 331. Pilot valve seat, 3311. Connecting hole, 332. Pilot valve core, 3321. Valve core body, 3322. Through hole, 3323. Circulation groove, 3324. Contact plane, 3325. Sealing surface, 3326. Sealing plane, 333. Valve core stopper, 3331. Channel outlet, 334. Pilot spring, 335. Pilot valve cavity, 35. First oil channel, 36. Second oil channel, 37. Third oil channel. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0039] In the description of this utility model, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0040] In the prior art, when the solenoid valve is in the safe operating mode, the gap between the pilot valve core and the outer valve sleeve (hydraulic housing) forms an oil outlet channel. However, this design presents two problems. First, the aforementioned gap is determined by two mating dimensions: the outer diameter of the pilot valve core and the inner diameter of the outer valve sleeve. Both components are machined, and dimensional tolerances are inevitable during the machining process. This gap tolerance cannot be precisely controlled, resulting in relatively large tolerances during mass production, causing large variations in the damping force of the shock absorber in the safe operating mode and poor stability. Second, this gap represents the oil outlet cross-section of the pilot valve chamber and is typically less than 0.1 mm. When the solenoid valve is de-energized, pressurized oil in the pilot valve chamber flows through this gap. However, due to machining, metallic and non-metallic impurities are inevitably generated in shock absorber components. When the oil flows through this gap, these impurities can easily become lodged, hindering the operation of the pilot valve core and, in turn, affecting the damping function of the entire shock absorber.

[0041] Regarding the above technical issues, such as Figure 1 and Figure 2 As shown, the present invention provides a solenoid valve for a variable damping shock absorber, comprising a coil portion 1, a hydraulic portion 3, and an electromagnetic portion 2 connected thereto. The hydraulic portion 3 includes a hydraulic housing 31 and a main valve component 32 and a pilot valve component 33 disposed therein, which communicate with each other. The pilot valve component 33 is provided with a central channel that allows pressurized oil to flow from the high-pressure area to the low-pressure area when the power is off. Compared to the prior art method of creating a gap between the inner and outer diameters of two parts, the size of the central channel formed by the pilot valve component 33 is easier to precisely control, achieving smaller tolerances without having to consider larger gap leakage caused by eccentricity of the mating parts. Furthermore, when oil flows through this central channel, the aperture of the central channel can be set larger than the size of impurity particles, allowing the impurities to flow directly, greatly reducing the risk of the pilot valve core 332 becoming stuck.

[0042] Specifically, the outer side of the electromagnetic part 2 is interference fit with the coil part 1 , and the inner side of the electromagnetic part 2 is interference fit with the hydraulic part 3 , thereby ensuring the firmness and stability of the entire electromagnetic valve structure.

[0043] Specifically, if Figure 4 、 Figure 5As shown, the pilot valve component 33 includes a pilot valve seat 331 fixed within the hydraulic housing 31. The pilot valve seat 331 divides the hydraulic housing 31 into a connected pilot valve area and a main valve area. A valve core stop 333 is fixed to one end of the pilot valve area. A pilot valve core 332 is disposed between the valve core stop 333 and the pilot valve seat 331 and is elastically connected to the pilot valve seat 331 via a pilot spring 334. When powered off, the solenoid 2 is separated from the pilot valve core 332. The pilot valve core 332, under the action of the pilot spring 334, abuts against the valve core stop 333, allowing the pressurized oil in the pilot valve area to flow only through the central channel.

[0044] A connecting hole 3311 is provided in the center of the pilot valve seat 331, a through hole 3322 is provided in the center of the pilot valve core 332, and a channel outlet 3331 is provided in the center of the valve core stop 333. The connecting hole 3311, through hole 3322, and channel outlet 3331 are interconnected to form a central channel. The channel outlet 3331 comprises a connected axial opening section and a flared section. The axial opening section is positioned toward the pilot valve core 332. The axial opening section and the flared section are clearance-matched with the armature push rod 242 of the solenoid unit 2, ensuring smooth discharge of pressurized oil when energized. Compared to the prior art method where the inner and outer diameters of two parts meet to create a clearance, the size of the central through hole 3322 of the pilot valve core 332 is easier to precisely control, achieving tighter tolerances while eliminating the need to consider larger clearance leaks caused by eccentricity of the mating parts. At the same time, when the oil flows through the through hole 3322, since the size of the through hole 3322 is larger than the size of the foreign particles, the foreign particles can flow directly, which greatly reduces the risk of the pilot valve core 332 being stuck.

[0045] like Figure 6 、 Figure 7 As shown, the pilot valve core 332 includes a valve core body 3321, a through hole 3322 is set in the center of the valve core body 3321, and a flow groove 3323 is set at intervals on the outer periphery of the valve core body 3321 for allowing the pressure oil to pass through when the power is on. The flow groove 3323 is set as an arc groove and has a large size. When the coil part 1 is energized, the pressure oil will flow through the flow groove 3323, and impurities in the pressure oil will easily pass through, and will not cause the pilot valve core 332 to get stuck.

[0046] One side of the valve core body 3321 is provided with a contact plane 3324 that seals with the armature push rod 242 of the solenoid unit 2 when energized, and a sealing surface 3325 that seals with the valve core stop 333 when energized. The sealing surface 3325 is configured as a conical surface and forms a line seal with one side of the valve core stop 333. When the solenoid valve is de-energized, the pilot valve core 332 is forced by the pilot spring 334 to form a seal with the valve core stop 333. This line seal minimizes leakage at this location. The other side of the valve core body 3321 is provided with a sealing plane 3326 that seals with the pilot valve seat 331 when energized. The configuration of these sealing surfaces ensures the sealing of the oil channel, ensuring stable oil flow in both energized and de-energized states, and improving the stability of the shock absorber's damping.

[0047] Specifically, if Figure 5 As shown, the main valve component 32 includes a main valve seat 321 fixed (interference-fitted) within the hydraulic housing 31 at one end away from the coil portion 1, and a main valve piston 322 slidably connected to the middle portion of the hydraulic housing 31. The main valve piston 322 is connected to the hydraulic housing 31 via an elastic component, ensuring that it will not disengage during operation. The elastic component includes a preload spring 323 positioned on the inner wall of the hydraulic housing 31 and a main valve spring 324 connected in series therewith. The end of the main valve spring 324 away from the preload spring 323 is in contact with the main valve piston 322, and the stiffness coefficient of the preload spring 323 is smaller than that of the main valve spring 324, ensuring that in the initial state, the main valve piston 322 and the main valve seat 321 have a relatively small preload force and low spring stiffness.

[0048] In addition, the main valve seat 321 and the hydraulic housing 31 are connected to each other via an adjusting gasket 325 . The adjusting gasket 325 can be single or multiple and is determined by the required preload force of the main valve piston 322 after calculation and adjustment.

[0049] Specifically, if Figure 5 As shown, the center of the main valve piston 322 is provided with an overflow hole 3221, the main valve seat 321 is provided with an oil inlet hole 3211, the hydraulic housing 31 is provided with a plurality of oil outlets 311 at intervals along the circumference, and the outer side of the hydraulic housing 31 is provided with a groove 312 (as shown in FIG. Figure 8As shown, the slot 312 and the solenoid unit 2 form an L-shaped flow channel 313. A first oil channel 35, i.e., the main circulation channel, is formed between the oil inlet hole 3211, the oil outlet 311, and the gap between the main valve piston 322 and the main valve seat 321. A second oil channel 36 is formed between the oil inlet hole 3211, the overflow hole 3221, the central channel, and the L-shaped flow channel 313. A third oil channel 37 is formed between the oil inlet hole 3211, the overflow hole 3221, the connecting hole 3311 in the center of the pilot valve seat 331, the gap between the pilot valve seat 331 and the pilot valve core 332, the circulation groove 3323, the channel outlet 3331 in the middle of the valve core stopper 333, and the L-shaped flow channel 313. When the solenoid valve is in the normal power-on working mode, the shock absorber pressure oil reaches the oil outlet 311 through the third oil channel 37 and the first oil channel 35; when the solenoid valve is in the power-off mode, the shock absorber pressure oil reaches the oil outlet 311 through the second oil channel 36 and the first oil channel 35. By precisely controlling the size of the through hole 3322 in the center of the pilot valve core 332, the damping force of the shock absorber in the power-off state can be stably controlled.

[0050] The hydraulic housing 31 , the pilot valve core 332 and the pilot valve seat 331 form a pilot valve cavity 335 ; the hydraulic housing 31 , the main valve piston 322 and the pilot valve seat 331 form a main valve cavity 326 , both of which can accommodate a certain volume of shock absorber pressure oil to achieve pressure transmission.

[0051] Specifically, if Figure 3As shown, the electromagnetic unit 2 includes a threaded housing 21 mounted in the shock absorber mounting hole. The outer side of the threaded housing 21 has an interference fit with the coil unit 1, and the inner side of the threaded housing 21 has an interference fit with the hydraulic unit 3. A magnetic pole 22 is fixed to the end of the threaded housing 21 near the coil unit 1. The electromagnetic unit 2 also includes a pole bushing 23 connected to the threaded housing 21. An armature assembly 24 is guided and installed in the pole bushing 23, which passes through the magnetic pole 22. One end of the armature assembly 24 is connected to the magnetic pole 22 via a return spring 25. The armature assembly 24 includes an armature push rod 242 and an armature body 241 that is press-fitted or riveted along its axial direction. Both ends of the armature push rod 242 extend through the armature body 241, and one end of the armature push rod 242 is connected to the pole bushing 23 via a guide bearing. The other end of the armature push rod 242 is guided and fitted with the magnetic pole 22. The end of the armature body 241 near the magnetic pole 22 is connected to the magnetic pole 22 via a return spring 25. The armature assembly 24 is a moving part that works in conjunction with the coil unit 1. When the coil assembly within the coil unit 1 is energized, the armature body 241 is driven by electromagnetic force, driving the armature push rod 242 to move. The coil unit 1 receives a current signal from the shock absorber controller. Current flowing through the coil unit 1 generates a magnetic field, which in turn generates an electromagnetic force within the solenoid unit 2. This electromagnetic force drives the armature body 241 within the solenoid unit 2, driving the armature push rod 242 to overcome the force of the return spring 25 and push the pilot valve core 332 toward the main valve assembly 32 of the hydraulic unit 3. When the coil unit 1 is de-energized, the armature assembly 24 returns to its initial position under the action of the return spring 25. This initial position is determined by the position of the armature push rod 242, and the travel of the armature push rod 242 is determined by the axial position of the magnetic pole 22. Furthermore, a contact surface 3324 is provided on the end of the pilot valve core 332 near the coil unit 1. This contact surface 3324 is in sealing contact with one end of the armature push rod 242.

[0052] The control method of the solenoid valve for the variable damping shock absorber includes a normal working mode and a safe working mode.

[0053] In normal working mode, the solenoid valve is in the energized state and receives the current signal from the controller. The magnitude of the working current received by the solenoid valve determines the pressure value of the shock absorber pressure oil flowing through the solenoid valve. The greater the working current received by the solenoid valve, the greater the pressure difference of the shock absorber pressure oil, and the greater the damping force of the shock absorber, and vice versa.

[0054] In the safe working mode, the solenoid valve is in a power-off state, the solenoid valve does not receive the current signal from the controller, and the damping force of the shock absorber is maintained at an intermediate level.

[0055] Specific working status such as Figures 9-11 As shown. Figure 9The diagram illustrates the working state of the solenoid valve in power-off mode. The specific control principle is as follows: in power-off mode, the armature push rod 242 remains disengaged from the pilot valve core 332 under the action of the return spring 25, and the pilot valve core 332 contacts and seals with the valve core stop 333 under the action of the pilot spring 334 and the hydraulic pressure. At the same time, after the shock absorber pressure oil flows from the oil inlet hole 3211 of the main valve seat 321 into the main valve cavity 326, there will be two circulation channels, and the pressures between the two channels will be related to and affect each other. The two channels include a first oil channel 35 and a second oil channel 36. The formation process of the first oil channel 35 is as follows: under the action of the pressure oil, the main valve piston 322 will overcome the spring force and separate from the main valve seat 321, forming the first oil channel 35 after separation. The shock absorber oil from the oil inlet flows through this channel to the oil outlet 311. The second oil channel 36 is formed as follows: An overflow hole 3221 is centrally defined in the main valve piston 322. Pressurized oil flows through this overflow hole 3221 into the main valve chamber 326, and then through the connecting hole 3311 in the center of the pilot valve seat 331 to the pilot valve chamber 335. Because the armature push rod 242 remains disengaged from the pilot valve core 332 by the action of the return spring 25, the pilot valve core 332 is sealed against the valve core stop 333 by the action of the pilot spring 334 and hydraulic pressure. Therefore, oil in the pilot valve chamber 335 can only flow through the through-hole 3322 of the pilot valve core 332, entering the L-shaped channel 313 and further reaching the oil outlet 311 of the solenoid valve.

[0056] As mentioned above, the fluid pressures in the two channels are interrelated and affect each other. When the through-hole 3322 in the center of the pilot valve core 332 is relatively large, the oil pressure in the pilot valve chamber 335 will be relatively low. Consequently, the pressure on the main valve piston 322 in the direction of the main valve seat 321 will be relatively small. The main valve piston 322 can be opened under relatively low oil inlet pressure, forming the main flow channel, namely, the first oil channel 35 mentioned above. Conversely, when the through-hole 3322 in the center of the pilot valve core 332 is relatively small, the main valve piston 322 requires a higher pressure to open. Therefore, the opening pressure of the main valve piston 322 can be adjusted by accurately defining the size of the through-hole 3322.

[0057] like Figure 10 The diagram illustrates the solenoid valve's operating state in normal operating mode (energized). As described above, the shock absorber's pressure oil flows from the solenoid valve's terminal oil inlet through overflow hole 3221 to the pilot valve chamber 335. When the solenoid valve is energized, the electromagnetic force acting on the armature push rod 242 contacts the pilot valve core 332. Once the set control current is reached, the armature push rod 242 presses the pilot valve core 332 against the pilot valve seat 331. The center of the armature push rod 242 is designed with a through hole. At this point, the oil pressure from the pilot valve chamber 335 is transmitted through the middle through hole of the armature push rod 242 to the upper end of the armature push rod 242, establishing pressure balance.

[0058] Figure 11 The diagram illustrates the working principle of the solenoid valve in normal operation. When the pilot valve core 332 is pressed against the pilot valve seat 331 by the electromagnetic force, the oil in the pilot valve chamber 335 cannot be discharged, and the oil pressure in the pilot valve chamber 335 becomes relatively high. This high oil pressure in the pilot valve chamber 335 is transmitted to the main valve chamber 326. When the hydraulic pressure in the pilot valve chamber 335 acting on the main valve piston 322 exceeds the hydraulic pressure generated at the oil inlet, the main valve piston 322 cannot open. When the pressure in the pilot valve chamber 335 increases to a level that overcomes the electromagnetic force, the pilot valve core 332 separates from the pilot valve seat 331, forming a flow channel. The oil in the pilot valve chamber 335 then flows through the flow groove 3323 on the outer periphery of the pilot valve core 332, the channel outlet 3331 of the valve core stop 333, and the L-shaped flow channel 313, exiting the L-shaped flow channel. The pressurized oil then flows out of the third oil channel 37. In this way, the pressure in the pilot valve cavity 335 will decrease. After the pressure in the pilot valve cavity 335 decreases, the liquid pressure acting on the main valve piston 322 will decrease. Under the action of the liquid pressure at the oil inlet, the main valve piston 322 will separate from the main valve seat 321 and form a main flow channel (i.e., the first oil channel 35). In this way, the shock absorber oil at the oil inlet will flow from this channel into the oil drain port.

[0059] In summary, the present invention is mainly used in situations where the solenoid valve of a variable damping shock absorber needs to have a safe working mode (solenoid valve power-off working mode). By optimizing the structural design of the pilot solenoid valve, the damping force of the shock absorber in the safe working mode can be stably controlled. When the solenoid valve is not energized, the pilot valve core 332 is subjected to the force of the pilot spring 334 and contacts and seals with the valve core stop 333. In the form of an online seal, the leakage at this location will be very small. The through hole 3322 in the middle of the pilot valve core 332 can be used to control the flow of oil in the pilot valve area in the safe working mode. Due to the design of the through hole 3322, it can usually be easily processed or achieved through a molding process. While reducing the processing cost, the processing size error of the hole will also be very small. Therefore, the size of the central through hole 3322 will be very close to the theoretical value, thus ensuring a relatively stable overflow capacity, thereby stably controlling the damping force of the shock absorber in the safe working mode.

[0060] At the same time, the design of the through hole 3322 in the center of the pilot valve core 332 also reduces the sensitivity of the pilot valve area to the cleanliness of the oil. Particulate impurities in the oil can be directly discharged to the outside of the solenoid valve through the through hole 3322, avoiding the jamming of the parts of the pilot part and causing abnormal function of the entire shock absorber.

[0061] The above description is merely an illustration of some principles of the present invention. This specification is not intended to limit the present invention to the specific structure and applicable scope shown and described. Therefore, all corresponding modifications and equivalents that may be used fall within the scope of the patent applied for by the present invention.

Claims

1. A solenoid valve for a variable damping shock absorber, comprising a coil portion, a hydraulic portion, and an electromagnetic portion connected therebetween, wherein the hydraulic portion comprises a hydraulic housing and a main valve component and a pilot valve component connected thereto, characterized in that: The pilot valve component is provided with a central channel for allowing the pressure oil to flow from the high-pressure area to the low-pressure area in a power-off state.

2. The solenoid valve for a variable damping shock absorber according to claim 1, characterized in that: The outer side of the electromagnetic part is interference-fitted with the coil part, and the inner side of the electromagnetic part is interference-fitted with the hydraulic part.

3. The solenoid valve for a variable damping shock absorber according to claim 1, wherein: The pilot valve component includes a pilot valve seat fixed in the hydraulic housing, and the pilot valve seat divides the hydraulic housing into a pilot valve area and a main valve area that are connected; A valve core stopper is fixed at one end of the pilot valve region, and a pilot valve core elastically connected to the pilot valve seat is provided between the valve core stopper and the pilot valve seat.

4. The solenoid valve for a variable damping shock absorber according to claim 3, wherein: A connecting hole is provided in the middle of the pilot valve seat, a through hole is provided in the middle of the pilot valve core, a channel outlet is provided in the middle of the valve core stopper, and the connecting hole, the through hole and the channel outlet are connected to form the central channel.

5. The solenoid valve for a variable damping shock absorber according to claim 4, characterized in that: The pilot valve core includes a valve core body, the through hole is provided at the center of the valve core body, and flow grooves for allowing pressure oil to pass through when power is supplied are provided at intervals on the outer circumference of the valve core body.

6. The solenoid valve for a variable damping shock absorber according to claim 5, characterized in that: One side of the valve core body is provided with a contact plane that is in sealing contact with the armature push rod of the electromagnetic part when the power is on, and a sealing surface that is in sealing contact with the valve core stop when the power is off. The other side of the valve core body is provided with a sealing plane that is in sealing contact with the pilot valve seat when the power is on.

7. The solenoid valve for a variable damping shock absorber according to claim 6, characterized in that: The sealing surface is configured as a conical surface, and the sealing surface is in sealing contact with a side line of the valve core stop.

8. The solenoid valve for a variable damping shock absorber according to claim 3, characterized in that: The channel outlet includes an axial opening section and a flared section connected to each other, and the axial opening section is arranged close to the direction of the pilot valve core.

9. The solenoid valve for a variable damping shock absorber according to claim 3, characterized in that: The pilot valve core is connected to the pilot valve seat through a pilot spring.

10. The solenoid valve for a variable damping shock absorber according to claim 5, characterized in that: The main valve component includes a main valve seat fixed in the hydraulic housing at one end away from the coil portion and a main valve piston slidably connected to the middle of the hydraulic housing. The main valve piston is connected to the hydraulic housing through an elastic component.

11. The solenoid valve for a variable damping shock absorber according to claim 10, characterized in that: The elastic component includes a preload spring positioned on the inner wall of the hydraulic housing and a main valve spring connected in series therewith, wherein one end of the main valve spring away from the preload spring is in contact with the main valve piston; the stiffness coefficient of the preload spring is smaller than the stiffness coefficient of the main valve spring.

12. The solenoid valve for a variable damping shock absorber according to claim 10, characterized in that: The main valve seat and the hydraulic housing are connected to each other through an adjusting gasket.

13. The solenoid valve for a variable damping shock absorber according to claim 10, characterized in that: An overflow hole is provided at the center of the main valve piston, an oil inlet hole is provided in the main valve seat, a plurality of oil outlets are provided at intervals along the circumference of the hydraulic housing, and a groove is provided on the outer side of the hydraulic housing near one end of the coil portion, and an L-shaped flow channel is formed between the groove and the electromagnetic portion; A first oil channel is formed between the oil inlet hole, the oil outlet and the gap between the main valve piston and the main valve seat; a second oil channel is formed between the oil inlet hole, the overflow hole, the central channel and the L-shaped flow channel; a third oil channel is formed between the oil inlet hole, the overflow hole, the connecting hole in the center of the pilot valve seat, the gap between the pilot valve seat and the pilot valve core, the flow groove, the channel outlet in the middle of the valve core stop and the L-shaped flow channel.

14. The solenoid valve for a variable damping shock absorber according to claim 10, characterized in that: A pilot valve cavity is formed between the hydraulic housing, the pilot valve core and the pilot valve seat; and a main valve cavity is formed between the hydraulic housing, the main valve piston and the pilot valve seat.

15. The solenoid valve for a variable damping shock absorber according to claim 1, characterized in that: The electromagnetic part includes a threaded shell installed in the shock absorber mounting hole, the outer side of the threaded shell is interference fit with the coil part, the inner side of the threaded shell is interference fit with the hydraulic part, and a magnetic pole is fixed to one end of the threaded shell close to the coil part; the electromagnetic part also includes a magnetic pole bushing connected to the threaded shell, and an armature assembly guided through the magnetic pole is installed in the magnetic pole bushing, and one end of the armature assembly is connected to the magnetic pole through a return spring.

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