A planetary gear type magnetorheological fluid medium retarder

Abstract

The present invention discloses a planetary gear type magnetorheological fluid medium retarder. Permanent magnets are inlaid on the end face of the housing. Due to the magnetic field, the shear stress and viscosity of the magnetorheological fluid in the gap between the rotor and the housing increase, resulting in an increase in damping and thus sealing, reducing leakage to a very small level. At the same time, the magnetorheological fluid also has a lubricating effect, which not only increases the pressure in the working chamber but also extends the service life. At the same time, a porous plate damping structure is adopted at the output port to control the damping at the output port and regulate and control the pressure in the working chamber. Finally, according to the vehicle speed signal, the retardation signal, and the wheel speed, the damping at the output port, the opening degree of the high and low pressure chamber channels, and the damping control are controlled, and the pressure in the working chamber is collected in real time to form a retarder torque closed-loop control, which can achieve a control frequency of 500 Hz to realize high-precision anti-lock performance.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic retarders, and particularly to a planetary gear type magnetorheological fluid medium retarder. Background Art

[0002] There are many intersections on urban roads, dense bus stops, and large passenger flows, so buses often need to brake frequently; mountain roads are steep and have many sharp turns, and medium and large trucks and buses driving on mountain sections for a long time also often need to brake. When the brake works frequently for a long time, it will cause rapid wear of the brake shoes, short service life of the brake friction pads, and loss of braking force or significant decline in braking performance due to brake fade, which also becomes the main cause of traffic accidents. Therefore, it is very necessary to equip an auxiliary braking system.

[0003] As an auxiliary braking component of a vehicle, a retarder reduces the load on the original vehicle's braking system by acting on the transmission system of the original vehicle, decelerates the vehicle evenly, improves the reliability of the vehicle's braking system, extends the service life of the braking system, and can thus significantly reduce the vehicle's use cost.

[0004] At present, there are eddy current retarders and hydraulic retarders. Eddy current retarders are large in size, heavy in body, consume a large amount of electric energy, and are greatly affected by the surrounding environmental temperature. Hydraulic retarders are relatively large in volume, slow in response speed, insufficient in low-speed braking force, and have large no-load losses. Summary of the Invention

[0005] The present invention adopts the following technical solutions. The input shaft is connected to the power of the vehicle transmission system; it rotates by itself with the energy of the power system. To reasonably adjust the rotational speed of the input shaft to achieve the rotational speed of the retarder that meets the actual requirements, mechanisms such as a speed increasing and torque reducing gear can be used to convert and transmit the rotational speed output from the power system gearbox to the input shaft end of the retarder.

[0006] The structure of the retarder includes an input shaft, bearings, oil seals, a housing assembly, a rotor assembly, and a clearance control assembly; among them, the housing assembly is provided with an oil inlet and an oil outlet for inputting and outputting oil, and also includes a front housing, a middle housing, and a rear housing that are assembled in sequence from front to back and are detachably connected; the rotor assembly includes a gear ring, planetary gears, and a sun gear; the clearance control assembly includes an oil distribution disc and an oil distribution disc sealing ring.

[0007] The oil distribution disc and the oil distribution disc sealing ring at least include a front oil distribution disc and a front oil distribution disc sealing ring. They are hermetically connected and arranged between the front housing and the rotor assembly. The outer diameter of the oil distribution disc is hermetically sealed with the housing cavity with a small gap and can slide axially. The oil distribution disc and the housing end face are separated by a special-shaped sealing ring into two regions, namely, a high-pressure region communicating with the output cavity and the high-pressure cavity, and a low-pressure region communicating with the oil inlet passage. The area of the high-pressure region is larger than that of the high-pressure region on the other side of the oil distribution disc, ensuring that a force can be generated to push the front oil distribution disc towards the rotor end face when the rotor is braked; the front housing, the middle housing and the rear housing are spliced to form the entire housing, and a cavity with a certain shape is formed inside the housing. The rotor assembly operates in the cavity through gear meshing and gear train cooperation, and sucks the magnetorheological fluid medium into the oil inlet cavity and presses it into the oil outlet cavity.

[0008] The retarder further includes bearings for transmission cooperation and oil seals for sealing; the bearings and oil seals are arranged on the left side of the front housing. The input shaft passes through the bearing hole and the front housing from the left side of the front housing and extends into the middle housing; an annular cavity is formed between the middle housing and the input shaft, and a ring gear, a planetary gear and a sun gear are arranged in the annular cavity; the ring gear is in the shape of an internal gear, and the sun gear is in the shape of an external gear; the input shaft drives the sun gear to rotate, the sun gear drives the planetary gear to revolve, and the planetary gear drives the ring gear to rotate. During the rotation process, each group of gears is in a meshed state. Along with the extrusion and cooperation between the planetary gear and the sun gear, ring gear 7, etc., the volume of the cavity changes, thereby forming an oil inlet cavity and an oil outlet cavity and generating pressure, sucking the magnetorheological fluid from the oil inlet, and then outputting high-pressure oil from the oil outlet after increasing the oil pressure.

[0009] Preferably, to further improve the control ability of the end clearance, the oil is specifically selected as magnetorheological fluid, a front floating oil distribution disc is adopted at the front end, and permanent magnets are inlaid at the sealing part of the housing that cooperates with the rear of the rotor. Under the action of the magnetic field, the magnetorheological fluid is magnetized. Due to the increase in shear stress and viscosity, it can seal an end clearance of 0.1 mm to 0.15 mm and can also generate high pressure. In this way, the rear oil distribution disc can be omitted, reducing the processing accuracy and improving the reliability. The front housing, the middle housing and the rear housing are spliced to form the entire housing, and a cavity with a certain shape is formed inside the housing. The rotor assembly operates in the cavity through gear meshing and gear train cooperation, and sucks the magnetorheological fluid medium into the oil inlet cavity and presses it into the oil outlet cavity.

[0010] The oil distribution disc and the oil distribution disc sealing ring at least include a front oil distribution disc and a front oil distribution disc sealing ring. They are sealingly connected and arranged between the front housing and the rotor assembly. The outer diameter of the oil distribution disc seals with the housing cavity with a small gap and can slide axially. There is a special-shaped sealing ring between the oil distribution disc and one side of the housing end face to separate two regions, namely the high-pressure region communicating with the output cavity and the high-pressure cavity, and the low-pressure region communicating with the oil inlet passage. The area of the high-pressure region is larger than that of the high-pressure region on the other side of the oil distribution disc, ensuring that a force can be generated to push the front oil distribution disc towards the rotor end face when the rotor brakes. The front end adopts a front floating oil distribution disc, and a permanent magnet is inlaid at the sealing part of the housing that mates with the rear of the rotor. Under the action of the magnetic field, the magnetorheological fluid is magnetized. Due to the increase in shear stress and viscosity, it can seal the end gap of 0.1 mm to 0.15 mm and can also generate high pressure. In this way, the use of the rear oil distribution disc can be avoided, reducing the machining accuracy and improving the reliability. The rear floating oil distribution disc can also be adopted simultaneously.

[0011] Preferably, a front floating oil distribution disc and a fixed oil distribution disc with a permanent magnet inlaid on the sealing surface of the rear housing can also be adopted.

[0012] Preferably, floating oil distribution discs can be adopted both front and back.

[0013] Furthermore, multiple groups of grooves with inlaid permanent magnets are arranged on the housing, and permanent magnets are fixed in the grooves. Corresponding electromagnetic coils are arranged at the oil passage in the housing, and the magnetic field intensity is controlled by the electromagnetic coils, thereby playing a role in gap permanent magnet sealing.

[0014] The size of the end gap can be controlled by the movement of the oil distribution disc to achieve pressure adjustment. The oil distribution disc can have only a front floating oil distribution disc and no fixed oil distribution disc at the back, or a rear floating oil distribution disc can also be adopted simultaneously. The front oil distribution disc is an axially floating oil distribution disc. The high-pressure areas on both sides of the rear oil distribution disc can have equal areas. When the rotor floats backward on the front oil distribution disc, it pushes the rotor backward, and then the rotor pushes the rear oil distribution disc. The rear oil distribution disc can swing slightly, thereby reducing the accuracy of the housing end face runout.

[0015] At the same time, the viscosity of the magnetorheological fluid can be controlled by the change of the magnetic field intensity, further adjusting the oil pressure, and realizing double-stage precise control and regulation.

[0016] Furthermore, under the condition that the control accuracy permits, to simplify the structure and control, the oil distribution disc structure is omitted, and the adjustment and control of the oil pressure are realized by controlling the viscosity of the magnetic fluid through the change of the magnetic field.

[0017] When the vehicle needs to slow down, the input shaft 1 drives the sun gear 15 to rotate, thereby driving the planet gear 14 to mesh with it and generating a rotary motion. With the meshing motion between the gears, the pressure change in the cavity makes the magnetorheological fluid medium move in the loop through the oil passage, thereby generating a braking torque.

[0018] Furthermore, by adjusting the magnetic field of the electromagnetic coil in the cavity oil passage, the viscosity of the magnetorheological fluid is changed to adjust the magnitude of the braking torque.

[0019] When the vehicle does not need retardation, an unloading pump can be used to unload the system and evacuate the magnetorheological fluid in the working cavity; the evacuation here means only leaving a small amount of oil in the working cavity, which not only ensures that there is no large oil flow resistance torque in the system when retardation is not required, enabling the vehicle power system to operate stably, but also the lubrication and heat dissipation of a small amount of oil further ensure the service life of the retarder.

[0020] To dissipate the heat energy converted from mechanical energy during the operation of the retarder into the air, a separate plate heat exchanger can be used to exchange heat with the engine cooling water, and the working medium is the magnetorheological fluid.

[0021] Permanent magnets are inlaid on the end face of the housing. Due to the magnetic field, the shear stress and viscosity of the magnetorheological fluid in the gap between the rotor and the housing increase, resulting in increased damping and sealing, reducing leakage to a very small level. At the same time, the magnetorheological fluid also has a lubricating effect, which not only increases the pressure in the working cavity but also extends the service life. At the output port, a porous plate damping structure is adopted to control the damping at the output port and regulate the pressure in the working cavity. Finally, based on the vehicle speed signal, retardation signal, and wheel speed, the damping at the output port, the opening degree of the high and low pressure chamber channels, and the damping control are adjusted, and the pressure in the working cavity is collected in real time to form a closed-loop control of the retarder torque, which can achieve a control frequency of 500 Hz to realize high-precision anti-lock performance.

[0022] Compared with the prior art, the present invention provides a planetary gear type magnetorheological fluid medium retarder, which has the following beneficial effects:

[0023] 1. Different from the planetary gear type high-pressure retarder with high-viscosity oil medium, the medium is magnetorheological fluid, whose viscosity is different under the action of magnetic fields of different intensities. Without the end clearance floating plate, the processing accuracy can be reduced, and a large clearance can be achieved to generate a high pressure difference with an end clearance of 0.02 mm, generating a large torque.

[0024] 2. Different from other magnetorheological fluid retarders, since there are multiple high and low pressure zones, multiple permanent magnets are required, which can form a uniform magnetic field in the working cavity, solve the problem of end clearance leakage while reducing meshing leakage, thus facilitating the formation of high pressure; the planetary gears are evenly distributed, so there is no lateral force and the reliability is good; the gear processing technology is mature, so the service life is long and the cost is low. With the same space, the single rotation displacement is large, so the volume is small, the weight is low, and the torque is large. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an exploded view of a planetary gear type magnetorheological fluid medium retarder of the present invention;

[0026] Figure 2This is the front view of the planetary gear type magnetorheological fluid medium retarder proposed by the present invention;

[0027] Figure 3 is Figure 2 the sectional view taken along the A-A direction in

[0028] Figure 4 is Figure 2 the sectional view taken along the B-B direction in

[0029] Figure 5 is the internal sectional view of the rotor mechanism;

[0030] Figure 6 is the internal sectional view of the retarder;

[0031] Figure 7 is the schematic diagram of the hydraulic system.

[0032] In the figure: 1. Shaft, 2. Tapered roller bearing, 3. Oil seal, 4. Front oil distribution plate seal ring, 5. Front oil distribution plate, 6. Front housing, 7. Ring gear, 8. Sealing block, 9. Middle housing, 10. Rear housing, 11. Heat exchanger, 12. Needle roller bearing, 13. Rear oil distribution plate, 14. Planet gear, 15. Sun gear, 16. Planet gear mechanism, 17. Outlet pressure sensor, 18. Outlet temperature sensor, 19. Relief valve, 20. Fine filter screen, 21. Filter screen protection valve, 22. Relief port, 23. Pilot relief valve, 24. Inlet oil filter screen, 25. Inlet oil check valve, 26. Unloading valve, 27. Oil replenishing and venting valve, 28. Oil storage and expansion tank, 29. Supply oil pump safety valve, 30. Supply oil pump, 31. Supply oil pump control valve, 32. Supply oil pump pressure sensor. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0035] Embodiment 1:

[0036] Refer to Figures 1-7As shown, the input shaft 1 is connected to the power of the vehicle transmission system; it rotates by itself with the energy of the power system. To reasonably adjust the rotational speed on the input shaft 1 to achieve the rotational speed of the retarder that meets the actual requirements, mechanisms such as a speed increasing and torque reducing gear can be used to transfer the output rotational speed of the power system gearbox to the end of the retarder input shaft 1 after conversion.

[0037] The structure of the retarder includes an input shaft 1, bearings 2, oil seals 3, a housing assembly, a rotor assembly, and a clearance control assembly; among them, the housing assembly is provided with an oil inlet and an oil outlet for inputting and outputting oil, and also includes a front housing 6, a middle housing 9, and a rear housing 10 that are assembled in sequence from front to back and are detachably connected; the rotor assembly includes a gear ring 7, planet gears 14, and a sun gear 15; the clearance control assembly includes a distribution disc and a distribution disc sealing ring.

[0038] The distribution disc and the distribution disc sealing ring at least include a front distribution disc 5 and a front distribution disc sealing ring 4, which are sealingly connected and arranged between the front housing 6 and the rotor assembly; the front housing 6, the middle housing 9, and the rear housing 10 are spliced to form the entire housing, and a cavity with a certain shape is formed inside the housing. The rotor assembly operates in the cavity through gear meshing and gear train cooperation, sucks the magnetorheological fluid into the oil inlet cavity, and presses it out from the output cavity, converting the vehicle kinetic energy into the pressure energy of the medium, and then into heat energy.

[0039] The retarder also includes bearings 2 for transmission cooperation and oil seals 3 for sealing; the bearings 2 and the oil seals 3 are arranged on the left side of the front housing 6. The input shaft 1 passes through the bearing hole and the front housing 6 from the left side of the front housing 6 and extends into the middle housing 9; an annular cavity is formed between the middle housing 9 and the input shaft 1, and a gear ring 7, planet gears 14, and a sun gear 15 are arranged in this annular cavity; the gear ring 7 is in the shape of an internal gear, and the sun gear 15 is in the shape of an external gear; the input shaft 1 drives the sun gear 15 to rotate, the sun gear 15 drives the planet gears 14 to revolve, and the planet gears 14 drive the gear ring 7 to rotate. During the rotation process, each group of gears is in a meshing state. Along with the squeezing cooperation between the teeth of the planet gears 14 and the sun gear 15, the gear ring 7, etc., the volume of the cavity changes, and then an oil inlet cavity and an oil outlet cavity are formed and pressure is generated, sucking the magnetorheological fluid from the oil inlet and outputting it from the oil outlet after increasing the oil pressure to generate a high-pressure medium.

[0040] Embodiment 2:

[0041] To further improve the control ability of the end clearance, specifically, the oil is selected as magnetorheological fluid. The front housing 6, the middle housing 9, and the rear housing 10 are spliced to form the entire housing, and a cavity with a certain shape is formed inside the housing. The rotor assembly operates in the cavity through gear meshing and gear train cooperation and sucks the magnetorheological fluid medium into the oil inlet cavity and presses it into the oil outlet cavity.

[0042] Furthermore, multiple groups of grooves with embedded permanent magnets are provided on the housing, and corresponding electromagnetic coils are arranged at the oil channels inside the housing. The electromagnetic coils are used to control the magnetic field intensity, thereby playing a role in gap permanent magnet sealing.

[0043] In this example, the size of the end gap can be controlled by the movement of the flow distribution plate to achieve pressure adjustment; at the same time, the viscosity of the magnetorheological fluid can be controlled by the change of the magnetic field intensity, further adjusting the oil pressure, and realizing double-stage precise control regulation.

[0044] Embodiment 3:

[0045] Under the condition that the control accuracy permits, in order to simplify the structure and control, the flow distribution plate structure in Embodiment 2 can be omitted. In this working condition, the oil pressure adjustment and control are realized by controlling the viscosity of the magnetorheological fluid through the change of the magnetic field;

[0046] When the vehicle needs to slow down, the input shaft 1 drives the sun gear 15 to rotate, thereby driving the planet gear 14 to mesh with it and generate a rotary motion. With the meshing motion between the gears, the pressure change in the cavity causes the magnetorheological fluid medium to move in the loop through the oil channel, thereby generating a braking torque.

[0047] Furthermore, by adjusting the magnetic field of the electromagnetic coil in the cavity oil channel, the viscosity of the magnetorheological fluid is changed to realize the adjustment of the braking torque magnitude.

[0048] When the vehicle does not need to slow down, a relief pump can be used to unload the system and evacuate the magnetorheological fluid in the working cavity; the evacuation here means only retaining a small amount of oil in the working cavity. This not only ensures that there is no large oil flow resistance torque in the system when deceleration is not required, enabling the vehicle power system to operate stably, but also the lubrication and heat dissipation of a small amount of oil further ensure the service life of the retarder.

[0049] To dissipate the heat energy converted from mechanical energy during the operation of the retarder into the air, a separate plate heat exchanger can be used to exchange heat with the engine cooling water, and the working medium is the magnetorheological fluid.

[0050] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A planetary gear type magnetorheological fluid medium retarder, comprising an input shaft, bearings, oil seals, a housing assembly, a rotor assembly, and a magnetorheological fluid control assembly; the retarder uses magnetorheological fluid as the medium oil, and an oil inlet and an oil outlet for inputting and outputting oil are provided on the housing assembly, and further includes a front housing, a middle housing, and a rear housing that are assembled in sequence from front to back and are detachably connected; characterized in that: The rotor assembly includes a gear ring, planet gears and a sun gear; the magnetorheological fluid control assembly includes a permanent magnet and an electromagnetic coil; the front housing, the middle housing and the rear housing are spliced to form the whole housing, and a cavity with a certain shape is formed inside the housing. The rotor assembly operates in the cavity through gear meshing and gear train cooperation, and sucks the magnetorheological fluid medium into the oil inlet cavity and presses it into the oil outlet cavity; it also includes an oil distribution disc and an oil distribution disc sealing ring. The oil distribution disc and the oil distribution disc sealing ring at least include a front oil distribution disc and a front oil distribution disc sealing ring. They are hermetically connected and arranged between the front housing and the rotor assembly. The outer diameter of the oil distribution disc is sealed with a small gap with the housing cavity and can slide axially; there is a special-shaped sealing ring between the oil distribution disc and the housing end face to separate two areas, namely a high-pressure area communicating with the output cavity and the high-pressure cavity, and a low-pressure area communicating with the oil inlet passage; the area of the high-pressure area is larger than the area of the high-pressure area on the other side of the oil distribution disc, ensuring that a force can be generated to push the front oil distribution disc towards the rotor end face when the rotor brakes; a front floating oil distribution disc is adopted at the front end, and a permanent magnet is inlaid at the sealing part of the housing matched with the rear of the rotor.

2. A planetary gear type magnetorheological fluid medium retarder as described in claim 1, characterized in that: Multiple grooves with inlaid permanent magnets are arranged on the housing, and the permanent magnets are fixed in the grooves; corresponding electromagnetic coils are arranged at the oil passages in the housing, and the magnetic field intensity is controlled by the electromagnetic coils, thereby playing a role in permanent magnet sealing of the gap.

3. A planetary gear type magnetorheological fluid medium retarder as described in claim 1, characterized in that: The retarder also includes bearings for transmission cooperation and oil seals for sealing; the bearings and oil seals are arranged on the left side of the front housing.

4. A planetary gear type magnetorheological fluid medium retarder as described in claim 1, characterized in that: The input shaft passes through the bearing hole and the front housing from the left side of the front housing and extends into the middle housing; an annular cavity is formed between the middle housing and the input shaft, and a gear ring, planet gears and a sun gear are arranged in the annular cavity.

5. A planetary gear type magnetorheological fluid medium retarder as described in claim 1, characterized in that: The shape of the gear ring is an internal gear, and the shape of the sun gear is an external gear; the input shaft drives the sun gear to rotate, the sun gear drives the planet gears to revolve, and the planet gears drive the gear ring to rotate. During the rotation process, each group of gears is in a meshing state. Along with the extrusion and cooperation between the teeth of the planet gears and the sun gear and the gear ring, the volume of the cavity changes, thereby forming an oil inlet cavity and an oil outlet cavity and generating pressure, sucking the magnetorheological fluid from the oil inlet, and then outputting high-pressure oil from the oil outlet after increasing the oil pressure.

6. A vehicle, characterized in that: The vehicle is equipped with the planetary gear type magnetorheological fluid medium retarder according to any one of claims 1-5.

7. A control method for a planetary gear type magnetorheological fluid medium retarder according to any one of claims 1-5, characterized in that: When the vehicle needs to slow down, the input shaft drives the sun gear to rotate, thereby driving the planet gears to mesh with it and generating a rotary motion. Along with the meshing motion between the gears, the pressure change in the cavity makes the magnetorheological fluid medium move in the loop through the oil passage, thereby generating a braking torque.

8. The control method of the planetary wheel type magnetorheological fluid medium retarder according to claim 7, characterized in that: The viscosity of the magnetorheological fluid is changed by adjusting the magnetic field of the electromagnetic coil in the cavity, so as to realize the adjustment of the magnitude of the braking torque.

9. The control method of the planetary gear type magnetorheological fluid medium retarder according to claim 8, characterized in that: When the vehicle does not need to slow down, an unloading pump is used to unload the system.

Images