An electro-hydraulic servo system with built-in heat dissipation oil circuit

Abstract

The application belongs to the technical field of electro-hydraulic servo, and particularly relates to an electro-hydraulic servo system with built-in heat dissipation oil circuit. The system comprises a clutch device, wherein the clutch device comprises: an input shaft internally provided with a cooling oil channel; a power shaft coaxially sleeved on the outside of the input shaft and provided with an oil passing channel; a friction pair group arranged on the power shaft; and a driven disc sleeved on the outer circumferential side of the friction pair group and provided with an oil outlet hole. The oil passing channel is used for guiding the cooling oil in the cooling oil channel to the friction pair group, and the oil outlet hole is used for discharging the cooling oil flowing through the friction pair group. The application sets the special cooling oil channel and the oil passing channel in the input shaft and the power shaft, directly guides the cooling oil to the heating area of the friction pair group, and discharges the cooling oil through the oil outlet hole on the driven disc, thereby constructing an efficient internal forced cooling oil circuit, effectively inhibiting the temperature rise of the friction pair group during continuous work, ensuring the stability of the friction performance, and prolonging the service life of the assembly.

Description

Technical Field

[0001] This invention belongs to the field of electro-hydraulic servo control technology, specifically an electro-hydraulic servo system with a built-in heat dissipation oil circuit. Background Technology

[0002] In electro-hydraulic servo systems, the clutch mechanism is often used to transmit and regulate torque. In some applications that require precise simulation of specific working conditions (such as simulating the ground adhesion of a vehicle on different road surfaces), the clutch mechanism needs to operate in a semi-engaged slipping state for extended periods, and the transmitted torque is regulated by precisely controlling the clamping force of its friction pair assembly.

[0003] However, under this continuous slip-friction operating mode, the friction pairs of the clutch mechanism generate a large amount of heat due to intense friction. If this heat cannot be dissipated effectively and in a timely manner, the temperature of the friction pairs will rise sharply, not only burning the friction plates and shortening their service life, but also causing changes in the coefficient of friction, resulting in unstable and inaccurate torque control, seriously affecting the performance of the entire servo system and the accuracy of simulation results. Some existing clutch mechanism designs mainly focus on the transmission and disconnection of power, and their heat dissipation structures are often unable to cope with the heat dissipation requirements of such continuous high heat flux density. Therefore, how to efficiently dissipate heat from the friction pairs during operation has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this application is to provide an electro-hydraulic servo system with a built-in heat dissipation oil circuit, which aims to solve the technical problem in the prior art that the friction pair assembly of the electro-hydraulic servo system used to simulate working conditions easily generates a lot of heat during continuous operation, resulting in poor heat dissipation and affecting the system stability and lifespan.

[0005] To achieve the above objectives, this application provides an electro-hydraulic servo system with a built-in cooling oil circuit, including a clutch device, the clutch device comprising: The input shaft has a cooling oil passage extending axially inside it. The power shaft is coaxially sleeved outside the input shaft and rotates synchronously with the input shaft. An oil passage is provided on the power shaft, which connects the cooling oil passage to the outer periphery of the power shaft. The baffle and the bearing plate are fixedly connected to the two ends of the drive shaft, respectively. The pressure plate is axially slidably mounted on the drive shaft and is located between the baffle and the bearing plate; The friction pair assembly is located between the baffle and the pressure plate, and is connected to the outlet of the oil passage on the outer periphery of the power shaft; The piston assembly is axially slidably sleeved on the power shaft and fixedly connected to the pressure plate; The driven disc is fitted onto the outer periphery of the friction pair assembly, and several oil outlet holes communicating with the friction pair assembly are provided on the side wall of the driven disc located on the outer side of the friction pair assembly. The oil passage is used to guide the cooling oil in the cooling oil passage to the friction pair assembly, and the oil outlet is used to discharge the cooling oil flowing through the friction pair assembly.

[0006] Furthermore, the oil passage includes a first radial oil guide hole, an axial oil guide hole, and a second radial oil guide hole sequentially formed from the inside to the outside along the radial direction of the power shaft; wherein: The axial guide oil hole extends along the axial direction of the power shaft; The two ends of the first radial oil guide hole are connected to the cooling oil channel and the axial oil guide hole, respectively. Multiple second radial oil guide holes are provided along the axial direction of the axial oil guide hole, and the two ends of each second radial oil guide hole are connected to the axial oil guide hole and the inner circumferential side of the friction pair assembly, respectively.

[0007] Furthermore, the power shaft is provided with multiple sets of oil guiding units along the circumferential direction. Each set of oil guiding units includes an axial oil guiding hole and multiple second radial oil guiding holes distributed along the axial direction of the axial oil guiding hole, and one set of oil guiding units is connected to the first radial oil guiding hole. A reserved groove is provided at one end of the baffle facing the power shaft. The reserved groove is opposite to and connected to multiple axial oil guide holes arranged in the circumferential direction. The axial oil guide holes connected to the first radial oil guide hole guide the cooling oil into the reserved groove, and distribute the cooling oil to the axial oil guide holes in the other groups of oil guide units through the reserved groove.

[0008] Furthermore, there are two first radial oil guide holes, which are located at the two ends of the axial oil guide hole that communicates with the first radial oil guide hole; the oil outlets of the multiple second radial oil guide holes of each oil guide unit are arranged from one end of the friction pair group to the other end along the axial direction of the power shaft.

[0009] Furthermore, it also includes a cooling tank containing cooling oil, with the clutch device immersed in the cooling oil inside the cooling tank. The oil outlet of the driven plate is connected to the cooling tank, and the oil outlet of the cooling tank is connected to the oil cooling system.

[0010] Furthermore, the inner wall of the cooling box is provided with a grid-like ribbed formed by the intersection of transverse and longitudinal ribbed ribs.

[0011] Furthermore, it also includes a pressure control component. Hydraulic chambers are respectively provided on both sides of the piston assembly along the axial direction. The two hydraulic chambers are used to drive the piston assembly to move bidirectionally along the power shaft. The pressure control component is used to control the pressure entering the two hydraulic chambers to drive the piston assembly to move axially, and to control the clamping force of the pressure plate on the friction pair assembly through the axial movement of the piston assembly.

[0012] Furthermore, the piston assembly includes a piston body that is axially slidably mounted on the power shaft, with one end of the piston body sealing with the power shaft to form a first hydraulic chamber, and the other end of the piston body sealing with the bearing plate to form a second hydraulic chamber. The power shaft is provided with a first oil passage connected to the first hydraulic chamber and a second oil passage connected to the second hydraulic chamber. The input shaft is provided with a first oil delivery channel connected to the first oil passage and a second oil delivery channel connected to the second oil passage. The first oil delivery channel and the second oil delivery channel are both set separately from the cooling oil channel.

[0013] Furthermore, the power shaft includes a large-diameter end and a small-diameter end arranged coaxially, with the outer diameter of the large-diameter end being larger than that of the small-diameter end, and a shoulder being formed between the large-diameter end and the small-diameter end; the piston body is fitted onto the small-diameter end. The shoulder extends towards the large-diameter end to form a concave portion, which seals with the first end face of the piston body to form a first hydraulic chamber; the inner wall of the bearing plate, the outer peripheral surface of the small-diameter end, and the second end face of the piston body seal to form a second hydraulic chamber.

[0014] Furthermore, it also includes a pressure control component, which includes an oil outlet circuit, an oil return circuit, and a servo valve. The oil outlet circuit and the oil return circuit are connected to the first oil distribution circuit and the second oil distribution circuit respectively through the servo valve. The first oil distribution circuit is connected to the first hydraulic chamber, and the second oil distribution circuit is connected to the second hydraulic chamber. A pressure reducing valve is installed on the oil outlet circuit. A temperature sensor is installed on the oil outlet circuit, and a pressure sensor is installed on each of the first and second oil distribution circuits.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention constructs a highly efficient internal forced cooling oil circuit by setting up dedicated cooling oil channels and oil passages inside the input shaft and power shaft, directly and precisely guiding the cooling oil to the heat-generating area of ​​the friction pair assembly, and discharging it through the oil outlet on the driven plate. This structure can directly apply the cooling oil to the heat source, resulting in higher heat dissipation efficiency compared to traditional external cooling or oil bath cooling. It can effectively suppress the temperature rise of the friction pair assembly during continuous operation, ensure the stability of friction performance, and extend the service life of the components.

[0016] (2) By setting up a cooling box and immersing the clutch device in it, the present invention, in conjunction with the external oil cooling system, forms a dual heat dissipation system that combines internal and external cooling, further enhancing the overall heat dissipation capacity and ensuring that the system can still maintain a reasonable operating temperature range under extreme conditions. The grid-like ribs inside the cooling box can effectively suppress the resonance that the cooling oil may generate when the system is working, improving the operational stability and reliability of the entire system.

[0017] (3) By setting hydraulic chambers on both sides of the piston assembly and using a pressure control component to precisely control the pressure in both chambers, the present invention can realize bidirectional driving of the piston assembly and real-time, continuous adjustment of the clamping force of the friction pair assembly. This enables the system to not only achieve the engagement and disengagement of power, but also to accurately simulate different magnitudes of ground adhesion, meeting the needs of high-performance testing and simulation applications, and improving control accuracy and response speed. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is an overall structural diagram of a clutch device provided in an embodiment of this application; Figure 2 A cross-sectional structural diagram (I) of a clutch device provided in an embodiment of this application; Figure 3 for Figure 2 Enlarged view of part A in the image; Figure 4 A structural diagram (I) of a power shaft provided in an embodiment of this application; Figure 5 A structural diagram (II) of a power shaft provided in an embodiment of this application; Figure 6 This is an assembly structure diagram of a cooling box and a clutch device provided in an embodiment of this application; Figure 7 Cross-sectional structural diagram (II) of a clutch device provided in an embodiment of this application; Figure 8 for Figure 7 Enlarged view of part B in the image; Figure 9 This is a structural diagram of a pressure control component provided in an embodiment of this application.

[0020] Wherein: 1-Input shaft, 11-Cooling oil passage, 12-First oil supply passage, 13-Second oil supply passage, 2-Power shaft, 21-Oil passage, 211-First radial oil guide hole, 212-Axial oil guide hole, 213-Second radial oil guide hole, 22-First oil passage, 23-Second oil passage, 24-Large diameter end, 25-Small diameter end, 26-Shaft shoulder, 261-Inner recess, 3-Baffle, 31-Reserved groove, 4-Bearing plate, 5-Pressure plate, 6-Friction pair assembly, 7-Piston assembly 71-Piston body, 72-First hydraulic chamber, 73-Second hydraulic chamber, 74-Push ring, 8-Driven plate, 81-Oil outlet, 9-Cooling box, 10-Pressure control assembly, 101-Oil outlet, 102-Oil return, 103-Servo valve, 104-First oil distribution line, 105-Second oil distribution line, 106-Pressure sensor, 107-Pressure reducing valve, 108-Temperature sensor, 109-Accumulator, 110-Adjustable damping, 111-Bypass valve, 20-Clutch device. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] The following is in conjunction with the appendix Figure 1 To be continued Figure 9 The invention is described in detail with specific embodiments.

[0023] Please see Figures 1 to 9 This application provides an electro-hydraulic servo system with a built-in cooling oil circuit, aiming to solve the problems of insufficient heat dissipation in the clutch device, easy generation of local high temperature, and inability to adjust the clamping force accurately in real time to simulate different adhesion conditions in the prior art. The system achieves efficient heat dissipation and accurate dynamic simulation of output torque by setting up an internal cooling oil circuit and an external cooling circulation, combined with bidirectional hydraulic closed-loop control.

[0024] For specific embodiments, see [link / reference]. Figure 2 and Figure 3The electro-hydraulic servo system with built-in cooling oil circuit of this application includes a clutch device 20. The clutch device 20 includes an input shaft 1, a power shaft 2, a baffle 3, a bearing plate 4, a pressure plate 5, a friction pair assembly 6, a piston assembly 7, and a driven plate 8. The input shaft 1 has a cooling oil channel 11 extending axially inside it. This cooling oil channel 11 is the initial inlet for cooling oil to enter the clutch device 20. The power shaft 2 is coaxially fitted outside the input shaft 1 and rotates synchronously with it. An oil passage 21 is formed on the power shaft 2. The purpose of the oil passage 21 is to further guide the cooling oil from the cooling oil channel 11 of the input shaft 1 to the critical parts that require cooling. That is, the oil passage 21 extends to the outer periphery of the power shaft 2, allowing cooling oil to be transferred to the outer periphery of the power shaft 2. It should be noted that the end of the cooling oil channel 11 in the oil inlet direction of this application has an oil outlet penetrating the outer wall of the input shaft 1, which communicates with the oil passage 21. Correspondingly, the first end of the oil inlet direction of the cooling oil channel 11 is also provided with an oil inlet that penetrates the outer wall of the input shaft 1, thereby realizing the interconnection of the oil circuits.

[0025] To achieve power transmission and control, the clutch device 20 also includes a friction pair assembly 6, which comprises alternating inner and outer friction plates. The inner friction plates are axially slidably connected to the drive shaft 2 via splines, and the outer friction plates are axially slidably connected to the inner circumferential surface of the driven disc 8 via splines. When the friction pair assembly 6 is pressed, power can be transmitted from the drive shaft 2 through the inner and outer friction plates to the driven disc 8, thereby driving an external load. The friction pair assembly 6 is pressed or released by an axially movable pressure plate 5. The oil passage 21 connects the cooling oil passage 11 to the outer circumference of the drive shaft 2 and ultimately guides the cooling oil to the friction pair assembly 6. The baffle 3 and the bearing plate 4 are fixedly connected to the axial ends of the drive shaft 2, respectively, to limit the axial movement range of the moving components such as the pressure plate 5 and the friction pair assembly 6. The pressure plate 5 is axially slidably fitted onto the drive shaft 2 and is located between the baffle 3 and the bearing plate 4. Friction pair assembly 6 is positioned between baffle 3 and pressure plate 5, with its inner circumference connected to the outlet of oil passage 21 on the outer circumference of power shaft 2, ensuring that cooling oil can directly act on friction pair assembly 6. Piston assembly 7 is axially slidably fitted onto power shaft 2 and fixedly connected to pressure plate 5, used to provide the driving force for pressing or releasing friction pair assembly 6. Driven disc 8 is fitted onto the outer circumference of friction pair assembly 6, used to receive and output the power transmitted by friction pair assembly 6. To allow cooling oil to circulate, several oil outlet holes 81 communicating with friction pair assembly 6 are provided on the side wall of driven disc 8 located on the outer side of friction pair assembly 6.

[0026] This application, through the aforementioned structure, enables the oil passage 21 on the power shaft 2 to effectively guide the cooling oil in the cooling oil passage 11 to the inner circumference of the friction pair assembly 6 for direct cooling, while the oil outlet 81 smoothly discharges the cooled oil that has absorbed heat, forming a basic internal cooling flow path. This structure allows the cooling oil to act directly on the heat source, resulting in higher heat dissipation efficiency compared to traditional external cooling or oil bath cooling. It effectively suppresses the temperature rise of the friction pair assembly 6 during continuous operation, ensuring stable friction performance and extending the service life of the components. Specifically, the cooling oil is guided from the cooling oil passage 11 on the input shaft 1 through the oil passage 21 on the power shaft 2 to the outer circumference of the power shaft 2, with its outlet facing the friction pair assembly 6. When the clutch device 20 is working, especially in a semi-clutch or high-power transmission state, a large amount of heat is generated between the friction pair assemblies 6. At this time, the cooling oil is directly sprayed onto these heat-generating core areas, effectively absorbing the heat. The oil, having absorbed heat, flows outwards through the gaps between the friction pair groups 6 under the action of centrifugal force and internal pressure, and is finally discharged through several oil outlet holes 81 opened on the side wall of the driven disc 8. This forms a forced cooling flow path from the inside out, running through the entire friction pair group 6, ensuring the thermal stability of the clutch device 20 under harsh operating conditions.

[0027] Further, see Figure 3 , Figure 4 and Figure 5 To make the flow path of the cooling oil clearer and more efficient, the internal structure of the oil passage 21 was further optimized. Specifically, the oil passage 21 includes a first radial oil guide hole 211, an axial oil guide hole 212, and a second radial oil guide hole 213, which are sequentially opened from the inside to the outside along the radial direction of the power shaft 2. The axial oil guide hole 212 is a channel extending along the axial direction of the power shaft 2. The two ends of the first radial oil guide hole 211 are connected to the cooling oil passage 11 in the input shaft 1 and the axial oil guide hole 212, respectively, and its function is to establish radial communication from the cooling oil passage 11 to the axial oil guide hole 212. Multiple second radial oil guide holes 213 are provided along the axial direction of the axial oil guide hole 212, and the two ends of each second radial oil guide hole 213 are connected to the axial oil guide hole 212 and the periphery of the friction pair assembly 6, respectively. The purpose of this multi-channel design of the second radial oil guide hole 213 is to realize the radial injection of cooling oil onto the friction pair group 6, which solves the problem that a single channel cannot cover the entire friction pair group 6, and realizes the precise guidance of the flow direction and flow rate of cooling oil.

[0028] Furthermore, in some embodiments, to ensure that the cooling oil can be evenly distributed across the entire circumference of the friction pair assembly 6, the drive shaft 2 is provided with multiple sets of oil guiding units along its circumference. Each set of oil guiding units includes a axial oil guiding hole 212 and multiple second radial oil guiding holes 213 distributed axially along the axial oil guiding hole 212. However, due to structural limitations, typically only one or a few first radial oil guiding holes 211 can directly communicate with the cooling oil channel 11 of the input shaft 1. In order to evenly distribute the cooling oil from this single inlet to all the circumferential oil guiding units, the baffle 3 is provided with an annular reserved groove 31 at one end facing the drive shaft. This reserved groove 31 is opposite to and communicates with the ends of the multiple circumferentially arranged axial oil guiding holes 212. Its working principle is as follows: the axial oil guide hole 212, which is connected to the first radial oil guide hole 211, first guides the cooling oil into the annular reserved groove 31. The reserved groove 31 acts as an annular redistribution space, so that the oil pressure is evenly distributed here. Then, the cooling oil is evenly distributed to the axial oil guide holes 212 in the other oil guide units through the reserved groove 31, and then distributed to the corresponding second radial oil guide hole 213 through the axial oil guide hole 212, and then distributed to the friction pair group 6. By adding this reserved groove 31, this application solves the problem of uneven circumferential distribution of cooling oil with minimal structural cost, and achieves uniform circumferential cooling of the entire friction pair group 6.

[0029] For further details, please refer to [link / reference]. Figure 3 To increase the initial flow rate of cooling oil and ensure that the cooling oil covers the entire axial width of the friction pair assembly 6, two first radial oil guide holes 211 are preferably provided, located at opposite ends of the axial oil guide hole 212 connected to them. Simultaneously, the outlets of multiple second radial oil guide holes 213 in each oil guide unit are evenly arranged from one end of the friction pair assembly 6 to the other along the axial direction of the power shaft 2. This design increases the total flow rate by simultaneously supplying oil to the axial oil guide hole 212 from two inlets, and ensures sufficient cooling oil spray on all friction surfaces of the friction pair assembly 6 by distributing the outlets of the second radial oil guide holes 213. This application achieves a more thorough and uniform cooling effect on the friction pair assembly 6 through this dual optimization in both the axial and radial directions.

[0030] In one alternative implementation, see [link to relevant documentation] Figure 6To significantly enhance the overall heat dissipation capacity of the system, this application embodiment also provides an external cooling solution. This solution includes a cooling tank 9, with the clutch device 20 entirely immersed in cooling oil within the cooling tank 9. The oil outlet 81 of the driven plate 8 is directly connected to the internal space of the cooling tank 9, allowing the high-temperature oil discharged from the friction pair assembly 6 to directly enter the cooling tank 9. Simultaneously, the oil outlet of the cooling tank 9 is connected to an external oil cooling system (e.g., a radiator and oil pump). Its working principle is that the oil cooling system extracts the high-temperature oil from the cooling tank 9 for forced cooling, and then returns the cooled, low-temperature oil to the cooling tank 9. By establishing such a large external circulation, the heat generated by the clutch device 20 is efficiently transferred to the external environment, helping to alleviate the problem that relying solely on internal oil circuits and limited oil volume is insufficient to meet the heat dissipation requirements of high-power, long-term operation scenarios, further enhancing the overall heat dissipation capacity and ensuring that the system can maintain a reasonable operating temperature range even under extreme operating conditions.

[0031] Furthermore, in the aforementioned embodiment with a cooling tank 9, the inner wall of the cooling tank 9 is also provided with a grid-like rib formed by the intersection of transverse and longitudinal ribs. During vehicle movement, the oil in the cooling tank 9 is prone to periodic flow or sloshing due to sloshing. The purpose of this grid-like rib design is to act as a damping structure, its principle being to suppress oil sloshing by increasing the resistance to oil flow. Through this design, system resonance that may be caused by oil sloshing is effectively prevented, significantly improving the stability and reliability of the system under dynamic operating conditions.

[0032] In another preferred embodiment, see Figures 7 to 9 To achieve real-time and precise control of the clamping force of the clutch device 20, this application also includes a pressure control assembly 10. This design provides hydraulic chambers on both axial sides of the piston assembly 7, both of which can be energized with pressurized oil to drive the piston assembly 7 to move bidirectionally along the power shaft 2. The core function of the pressure control assembly 10 is to precisely control the pressure entering these two hydraulic chambers. Its working principle is to precisely control the magnitude and direction of the resultant force applied to the piston assembly 7 by adjusting the pressure difference between the two hydraulic chambers, thereby controlling the clamping force of the pressure plate 5 on the friction pair assembly 6. This bidirectional hydraulic control method not only achieves clamping and disengagement, but more importantly, it allows for continuous and rapid adjustment of the clamping force between zero and its maximum value, thus helping to solve the technical problem in the prior art of being unable to simulate different ground adhesion forces in real time.

[0033] Further, see Figure 8To achieve the aforementioned bidirectional hydraulic control, the piston assembly 7 comprises a piston body 71 axially slidably mounted on the power shaft 2. One end of the piston body 71 forms a first hydraulic chamber 72 with the power shaft 2 via a sealing structure, while the other end forms a second hydraulic chamber 73 with the support plate 4 via a sealing structure. To introduce pressurized oil into these two enclosed chambers, the power shaft 2 is provided with a first oil passage 22 communicating with the first hydraulic chamber 72 and a second oil passage 23 communicating with the second hydraulic chamber 73. Correspondingly, inside the input shaft 1, there is also a first oil supply channel 12 communicating with the first oil passage 22 and a second oil supply channel 13 communicating with the second oil passage 23. Crucially, these two oil supply channels and oil passages for pressure control are completely separate and independently configured from the aforementioned cooling oil passage 11 for heat dissipation. The cooling oil passage and the hydraulic oil passage do not interfere with each other and operate independently. This design ensures that the pressure and cleanliness of the hydraulic oil in the control system are not affected by the cooling oil, guaranteeing the accuracy and reliability of the control.

[0034] In a more specific embodiment, to form the first hydraulic cavity 72 and the second hydraulic cavity 73 within a limited space, the geometry of the power shaft 2 is designed to include a large-diameter end 24 and a small-diameter end 25 coaxially arranged, with the outer diameter of the large-diameter end 24 being larger than the outer diameter of the small-diameter end 25, and a shoulder 26 forming between the large-diameter end 24 and the small-diameter end 25; the piston body 71 is fitted onto the small-diameter end 25; at the shoulder 26, a recess 261 is machined along the direction of the large-diameter end 24, and this recess 261 seals with the first end face of the piston body 71 to form the first hydraulic cavity 72. Simultaneously, the inner wall of the bearing plate 4, the outer peripheral surface of the small-diameter end 25, and the second end face of the piston body 71 together form the second hydraulic cavity 73. This design, which utilizes different diameter segments and stepped surfaces of the shaft itself to construct the hydraulic cavity boundaries, leverages the geometric features of existing components to achieve a highly integrated and compact structural layout, avoiding complex additional parts.

[0035] Furthermore, the piston assembly 7 also includes a push ring 74 coaxially sleeved around the piston body 71. The push ring 74 is integrally formed with the piston body 71, and the pressure plate 5 is fixedly connected to the push ring 74. When the piston body 71 moves axially under hydraulic drive, the push ring 74 can synchronously and smoothly push the pressure plate 5, avoiding the eccentricity or uneven load problems that may occur due to separate assembly, and improving the uniformity of pressure distribution and the stability of operation during the engagement process of the clutch device 20.

[0036] For further details, please refer to [link / reference]. Figure 9To construct a complete closed-loop control system, the pressure control component 10 includes an oil outlet 101, an oil return 102, and a servo valve 103. The oil outlet 101 and oil return 102 are connected to a first branch oil circuit 104 and a second branch oil circuit 105 respectively via the servo valve 103. The first branch oil circuit 104 is connected to a first hydraulic chamber 72, and the second branch oil circuit 105 is connected to a second hydraulic chamber 73. The servo valve 103 can precisely adjust the flow rate and pressure to the two branch oil circuits according to the control signal. Furthermore, a pressure reducing valve 107 is installed on the oil outlet 101 to stabilize the main oil pressure of the system. More importantly, a pressure sensor 106 is installed on both the first branch oil circuit 104 and the second branch oil circuit 105 to monitor the actual pressure of the two hydraulic chambers in real time and feed the signal back to the controller. Simultaneously, a temperature sensor 108 can also be installed on the oil outlet 101 to monitor the oil temperature. Its working principle is that the controller, based on the target clamping force and the actual pressure fed back by the pressure sensor 106, performs closed-loop adjustment through the servo valve 103, thereby achieving high-precision and high-dynamic-response control of the clamping force. In this way, it ultimately achieves accurate simulation of different ground adhesion forces. For example, when simulating the transition of a vehicle from emergency braking on an asphalt road to an icy road surface, the controller issues a torque drop command, and the pressure control component 10 rapidly reduces the pressure of the second hydraulic chamber 73 while increasing the pressure of the first hydraulic chamber 72, causing the clamping force of the friction pair group 6 to decrease rapidly, thus accurately simulating the sharp drop in tire adhesion. Throughout the high-intensity test, thanks to the dual internal and external cooling system, the maximum temperature of the friction pair group 6 is stably controlled below a certain temperature value, far below the failure temperature of traditional clutch devices, ensuring the continuity of the test and the reliability of the results.

[0037] Furthermore, in some embodiments, an accumulator 109 is provided on both the oil outlet line 101 and the oil return line 102; an adjustable damper 110 and a bypass valve 111 are connected in parallel between the first branch oil line 104 and the second branch oil line 105. The accumulator 109 can effectively absorb and compensate for pressure fluctuations caused by oil pump pulsation or rapid valve action, making the pressure in the chamber more stable, thereby improving control accuracy. The branch consisting of the adjustable damper 110 and the bypass valve 111 is used to provide damping or achieve rapid pressure balance between the two hydraulic chambers under specific operating conditions (such as emergency shutdown).

[0038] The complete workflow of this application is as follows: When a specific ground adhesion force needs to be simulated, the controller issues a command for a target clamping force. Based on this command, the controller of the pressure control component 10 calculates the required oil pressure in the first hydraulic chamber 72 and the second hydraulic chamber 73. Based on the actual pressure and target pressure fed back by the pressure sensor 106, the controller drives the servo valve 103 to precisely adjust the oil flow rate into the two hydraulic chambers, causing the pressure inside the chambers to quickly reach the set value. The resulting pressure difference acts on the piston assembly 7, causing it to push the pressure plate 5 to precisely clamp the friction pair assembly 6, thereby outputting a torque corresponding to the target adhesion force on the driven plate 8. During this process, the input shaft 1 rotates, and cooling oil is pumped in through its cooling oil channel 11. The oil then passes through the first radial guide hole 211, the axial guide hole 212, the reserved groove 31, and the second radial guide hole 213, and is evenly sprayed onto the surface of the friction pair assembly 6, which is experiencing high-speed slippage. After passing through the friction pair assembly 6, the high-temperature oil is thrown into the cooling tank 9 from the oil outlet 81 of the driven plate 8. It mixes with the cold oil in the cooling tank 9, is then extracted and cooled by the external oil cooling system, and returns to the cooling tank 9, forming a continuous cycle. Simultaneously, the mesh-like ribs effectively suppress oil sloshing that may be caused by drastic changes in operating conditions.

[0039] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. An electro-hydraulic servo system with a built-in cooling oil circuit, comprising a clutch device, characterized in that, The clutch device includes: The input shaft has a cooling oil passage extending axially inside it. A power shaft is coaxially sleeved outside the input shaft and rotates synchronously with the input shaft. An oil passage is provided on the power shaft, and the oil passage connects the cooling oil passage to the outer periphery of the power shaft. The baffle and the bearing plate are respectively fixedly connected to both ends of the axial direction of the power shaft; The pressure plate is axially slidably fitted onto the power shaft and is located between the baffle and the bearing plate; A friction pair assembly is disposed between the baffle and the pressure plate, and is connected to the outlet of the oil passage on the outer periphery of the power shaft; The piston assembly is axially slidably sleeved on the power shaft and fixedly connected to the pressure plate; A driven disc is fitted onto the outer periphery of the friction pair assembly, and the driven disc has several oil outlet holes communicating with the friction pair assembly on its side wall located outside the friction pair assembly. The oil passage is used to guide the cooling oil in the cooling oil passage to the friction pair assembly, and the oil outlet is used to discharge the cooling oil flowing through the friction pair assembly.

2. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 1, characterized in that, The oil passage includes a first radial oil guide hole, an axial oil guide hole, and a second radial oil guide hole sequentially opened from the inside to the outside along the radial direction of the power shaft; wherein: The axial guide hole extends along the axial direction of the power shaft; The two ends of the first radial oil guide hole are respectively connected to the cooling oil channel and the axial oil guide hole; Multiple second radial oil guide holes are provided along the axial direction of the axial oil guide hole, and the two ends of each second radial oil guide hole are respectively connected to the axial oil guide hole and the inner circumferential side of the friction pair assembly.

3. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 2, characterized in that, The power shaft is provided with multiple sets of oil guiding units along the circumferential direction. Each set of oil guiding units includes a shaft oil guiding hole and multiple second radial oil guiding holes distributed along the axial direction of the shaft oil guiding hole. One set of oil guiding units is connected to the first radial oil guiding hole. The baffle is provided with a reserved groove at one end facing the power shaft. The reserved groove is opposite to and connected to the plurality of circumferentially arranged axial oil guide holes. The axial oil guide holes connected to the first radial oil guide hole guide the cooling oil into the reserved groove, and distribute the cooling oil to the axial oil guide holes in the other groups of oil guide units through the reserved groove.

4. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 3, characterized in that, There are two first radial oil guide holes, which are respectively located at the two ends of the axial oil guide hole that communicates with the first radial oil guide hole; the oil outlets of the plurality of second radial oil guide holes of each group of oil guide units are arranged from one end of the friction pair group to the other end along the axial direction of the power shaft.

5. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 1, characterized in that, It also includes a cooling tank containing cooling oil, the clutch device being immersed in the cooling oil in the cooling tank, the oil outlet of the driven plate being connected to the cooling tank, and the oil outlet of the cooling tank being connected to an oil cooling system.

6. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 5, characterized in that, The inner wall of the cooling box is provided with a grid-like rib plate formed by the intersection of transverse and longitudinal rib plates.

7. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 1, characterized in that, It also includes a pressure control component, wherein hydraulic chambers are respectively provided on both sides of the piston assembly along the axial direction, and the two hydraulic chambers are used to drive the piston assembly to move bidirectionally along the power shaft; the pressure control component is used to control the pressure entering the two hydraulic chambers to drive the piston assembly to move axially, and to control the clamping force of the pressure plate on the friction pair assembly through the axial movement of the piston assembly.

8. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 7, characterized in that, The piston assembly includes a piston body that is axially slidably mounted on the power shaft. One end of the piston body is sealed with the power shaft to form a first hydraulic chamber, and the other end of the piston body is sealed with the bearing plate to form a second hydraulic chamber. The power shaft is provided with a first oil passage communicating with the first hydraulic chamber and a second oil passage communicating with the second hydraulic chamber. The input shaft is provided with a first oil delivery channel communicating with the first oil passage and a second oil delivery channel communicating with the second oil passage. The first oil delivery channel and the second oil delivery channel are both separately arranged from the cooling oil channel.

9. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 8, characterized in that, The power shaft includes a large-diameter end and a small-diameter end arranged coaxially. The outer diameter of the large-diameter end is larger than the outer diameter of the small-diameter end, and a shoulder is formed between the large-diameter end and the small-diameter end. The piston body is sleeved on the small-diameter end. The shoulder extends toward the large-diameter end to form a concave portion, and the concave portion and the first end face of the piston body are sealed to form a first hydraulic cavity; the inner wall of the bearing plate, the outer peripheral surface of the small-diameter end and the second end face of the piston body are sealed to form a second hydraulic cavity.

10. The electro-hydraulic servo system with built-in cooling oil circuit according to claim 8, characterized in that, It also includes a pressure control component, which includes an oil outlet line, an oil return line, and a servo valve. The oil outlet line and the oil return line are respectively connected to a first oil distribution line and a second oil distribution line through the servo valve. The first oil distribution line is connected to the first hydraulic chamber, and the second oil distribution line is connected to the second hydraulic chamber. A pressure reducing valve is provided on the oil outlet line. A temperature sensor is provided on the oil outlet line, and a pressure sensor is provided on each of the first and second oil distribution lines.

Images