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WO2007038734A2 - Essieu vectoriel hydraulique - Google Patents

Essieu vectoriel hydraulique Download PDF

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Publication number
WO2007038734A2
WO2007038734A2 PCT/US2006/038017 US2006038017W WO2007038734A2 WO 2007038734 A2 WO2007038734 A2 WO 2007038734A2 US 2006038017 W US2006038017 W US 2006038017W WO 2007038734 A2 WO2007038734 A2 WO 2007038734A2
Authority
WO
WIPO (PCT)
Prior art keywords
differential
motor
pump
torque
hydrostatic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2006/038017
Other languages
English (en)
Other versions
WO2007038734A3 (fr
Inventor
Lawrence R. Folsom
Clive Tucker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Folsom Technologies Inc
Folsom Technologies International LLC
Original Assignee
Folsom Technologies Inc
Folsom Technologies International LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Folsom Technologies Inc, Folsom Technologies International LLC filed Critical Folsom Technologies Inc
Publication of WO2007038734A2 publication Critical patent/WO2007038734A2/fr
Publication of WO2007038734A3 publication Critical patent/WO2007038734A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H47/00—Combinations of mechanical gearing with fluid clutches or fluid gearing
    • F16H47/02—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type
    • F16H47/04—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type the mechanical gearing being of the type with members having orbital motion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K23/00—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for
    • B60K23/04—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for for differential gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H39/00—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution
    • F16H39/04—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit
    • F16H39/06—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type
    • F16H39/08—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type each with one main shaft and provided with pistons reciprocating in cylinders
    • F16H39/10—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type each with one main shaft and provided with pistons reciprocating in cylinders with cylinders arranged around, and parallel or approximately parallel to the main axis of the gearing
    • F16H39/14—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type each with one main shaft and provided with pistons reciprocating in cylinders with cylinders arranged around, and parallel or approximately parallel to the main axis of the gearing with cylinders carried in rotary cylinder blocks or cylinder-bearing members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H48/00—Differential gearings
    • F16H48/06—Differential gearings with gears having orbital motion
    • F16H48/08—Differential gearings with gears having orbital motion comprising bevel gears
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H48/00—Differential gearings
    • F16H48/20—Arrangements for suppressing or influencing the differential action, e.g. locking devices

Definitions

  • This invention relates to vehicle drive trains, and more particularly to a hydraulic vectoring axle capable of vectoring speed, and hence torque, differentially to the vehicle wheels at any desired ratio.
  • a vectoring differential powers both drive wheels in conditions where one wheel could slip and lose traction, or where differential torque to right and left wheels improves handling in curves.
  • An ordinary open differential standard on most vehicles, can lose traction by spinning one wheel during acceleration or cornering because the open differential shifts power to the wheel with less grip.
  • a vectoring axle is designed to deliver torque in the proper proportion to the wheel that is required for proper handling in curves.
  • torque biasing differential can produce close to ideal 50/50 power split to both drive wheels, resulting in improved traction over a conventional open differential.
  • a torque biasing differential can bias engine power to the outside wheel, minimizing or eliminating spinning of the inside wheel, thereby allowing earlier acceleration in the curve and exiting the corner at a higher speed.
  • a torque biasing differential used in an all-wheel-drive configuration can control loss of traction when the front wheels are on slippery surfaces such as ice and snow or mud, providing the appropriate biased traction needed to overcome these adverse conditions.
  • Hydro-mechanical Torque Vectoring Differential teaches a hydro-mechanical torque vectoring differential that can vector input torque from the engine to either wheel in an efficient, durable, and fully controllable manner.
  • hydro-mechanical torque vectoring differential that can vector input torque from the engine to either wheel in an efficient, durable, and fully controllable manner.
  • This invention provides a vectoring axle that uses axle speed to supply power for vectoring torque to either wheel by varying the speed of one wheel against the speed of the differential.
  • the vectoring axle is thus able to vector torque as long as the vehicle is moving, regardless of input torque to the differential.
  • the vectoring axle includes a differential for torque transmission from a prime mover via a drive shaft to right and left vehicle axles.
  • a hydrostatic pump and a hydrostatic motor are hydraulically coupled through fluid passages for connecting pressurized fluid from the pump to the motor for driving the motor, and for connecting spent fluid from the motor to suction ports on the pump for re- pressurizing by the pump.
  • a valve between the hydrostatic pump and motor controls fluid flow in flow passages through which the hydrostatic pump and motor are hydraulically coupled.
  • An epicyclic gear set having three members geared in series, is coupled between the differential, one of the right and left axles, a hydrostatic motor, and hydrostatic pump as follows: a) one of the axles is coupled to one member of the epicyclic gear set; b) a second member of the epicyclic gear set is geared to the differential carrier; and c) a third member is geared to the hydrostatic motor, a hydrostatic pump is geared to the differential input.
  • the hydrostatic pump has a displacement control for controlling the hydraulic displacement of the pump.
  • the motor rotates at a ratio of pump speed according to the ratio of the displacements between the pump and motor, causing the output shaft that is connected to one member of the planet set to rotate in relation to the member of the planet set that is geared to the differential housing.
  • Fig. 1 is a schematic diagram of a hydraulic vectoring differential in accordance with this invention, showing the straight ahead condition in which both wheels are turning at the same speed;
  • Fig. 2 is a schematic diagram showing torque transfer from the vehicle drive shaft through the differential carrier and the differential gearset to the right and left vehicle axles in straight-ahead driving mode.
  • Fig. 3 is a schematic diagram showing unequal distribution of torque from the differential carrier to the left axle during left torque vectoring
  • Fig. 4 is a schematic diagram showing unequal torque distribution from the differential carrier to the right axle during right torque vectoring
  • Fig. 5 is a schematic diagram showing the locked mode in which the motor is locked and therefore both torque and speed is equal to both wheels;
  • Fig. 6 is a control system schematic for the vectoring differential shown in Fig. 1,;
  • Fig. 7 is a schematic diagram of another embodiment of a hydraulic vectoring differential in accordance with this invention, showing the straight ahead condition in which both wheels are turning at the same speed;
  • Fig. 8 is a schematic diagram of a variation on the embodiment of Fig. 7;
  • Fig. 9 is a schematic diagram of a variation on the embodiment of Fig. 8;
  • Fig. 10 is a perspective view of one embodiment of the hydraulic vectoring differential shown schematically in Fig. 9;
  • Fig. 11 is a sectional side elevation of the embodiment shown in Fig. 11 ;
  • Fig. 12 is a sectional end elevation of the embodiment shown in Fig. 11;
  • Fig. 13 is a laid-out elevation of the gears and hydraulic elements of the hydraulic vectoring differential shown in Fig. 12, with the hydraulics rotated up to shown the mechanical connection to the epicyclic gear set; and
  • Fig. 14 is a perspective view of the hydrostatic units, showing the mechanical link between the units and the displacement control mechanism for the pump.
  • a speed vectoring axle is shown in a vehicle drive arrangement having a conventional input drive shaft 30 driving an input bevel gear 32 of a conventional bevel gear differential 35 having a conventional differential carrier 66.
  • Right and left axles 40, 42 are driven by the differential 35 in a conventional manner.
  • both axle shafts are driven with the same torque and speed, as is usual with conventional differentials.
  • An epicyclic gear set 50 is coupled between the differential carrier, one axle, a hydrostatic motor 80 and hydrostatic pump 90.
  • the epicyclic gear set 50 includes a planet carrier 52 that carries a plurality of planet gears 54 in geared engagement between a sun gear 55 and a ring gear 56.
  • the one axle (in the example shown in Fig. 1, it is the left axle 42) is coupled to one member of the epicyclic gear set 50.
  • the "one member” is the planet carrier 52, so the planet carrier 52 is driven at the rotational speed of the axle 42.
  • a lay shaft 60 is connected at one end (the right end in Fig. 1) via gears 62, 64 to the differential carrier 66 so that the lay shaft 60 rotates at a fixed ratio to the rotational speed of the differential carrier 66.
  • the other end of the lay shaft 60 (the left end in Fig.
  • the gear ratio between the lay shaft 60 and the differential carrier 66 is chosen so that the ring gear 56 is driven to rotate relative to the planet carrier 52 at a speed such that the third member of the epicyclic gear set 50 (in the case shown, the sun gear 55) is stationary when the axle 42 and the differential carrier 66 are rotating at the same speed, as in the straight ahead case.
  • the sun gear 55 is connected to the hydrostatic motor 80 via gear 85 on one end of a motor idler shaft 87, and a motor drive gear 89 on the other end of the idler shaft 87 in the example shown in Fig. 1. Therefore, when the vehicle is in the straight ahead case, there is no rotation of the motor hydrostatic unit 80. When the vehicle goes around a corner and there is some speed difference between the axle 42 and the differential carrier 66, the motor hydrostatic unit 80 will be driven to rotate by that relative speed difference. The direction of rotation of the hydrostatic unit 80 will be dependent on which axle, the right axle 40 or the left axle 42, goes faster than the differential carrier 66.
  • a variable displacement hydrostatic pump 90 is connected via a gear 92 to the input shaft 30 via the gear 62 on the lay shaft 60, which is engaged with the gear 64 connected to the differential carrier 66, in the example shown in Fig. 1.
  • the hydrostatic pump 90 will therefore always rotate at some fixed ratio of input speed.
  • the displacement of the pump 90 can be adjusted from zero to some maximum by way of a displacement control device, such as a hydraulic cylinder and piston 95 connected to the pump, and a pump displacement control valve 97, which can be electrically controlled by an actuator, such as a stepper motor 99 or the like.
  • the pump 90 is hydraulically coupled to the hydraulic motor 80 through main fluid flow circuit 108, 109, and the flow is controlled as shown by a main control valve 100, which is also electrically controlled by actuators 105, 106.
  • a pump displacement position sensor 102 provides pump displacement position feedback to a controller 175, shown in Fig. 6.
  • the motor 80 When the pump hydrostatic unit 90 is adjusted to have some displacement and is being driven by the gear 62, and the main control valve 100 is positioned to conduct flow of hydraulic fluid between the pump 90 and the motor 80 through the main fluid coupling circuit 108, 109 as shown in Fig. 1, the motor 80 will be driven to rotate at a speed determined by the displacement of the hydrostatic pump 90. This will cause the axle 42 to rotate relative to the differential carrier 66. Since both axle shafts are connected to each other via the standard differential 35, as one axle rotates relative to the differential carrier 66, the other axle will rotate at the same speed but in the opposite direction relative to the differential carrier 66, therefore speed (and hence torque) vectoring will take place.
  • the amount of this speed vectoring will depend on the relative displacements of the pump 90 to the motor hydrostatic unit 80. Since the flow rate from the motor 80 is relatively small under normal cornering in open differential mode it is anticipated that the motor 80 could be a fixed displacement unit requiring just the displacement of the pump 90 and a control valve to be operated to effect torque vectoring.
  • the pump 90 could be either displaced through a positive and negative angle to achieve torque vectoring in either direction or (as shown in Fig. 1) the main control valve 100 could switch the flow from the pump 90 to the opposite channels in the motor 80, making it possible for the pump 90 to be designed to stroke in one direction only. This may have benefits in reducing reaction times as it will require less time to activate the control valve 100 as opposed to stroking the pump 90 from a negative angle to a positive angle.
  • the motor 80 can either be hydraulically connected so that flow can freely pass from one side of the motor to the other or be blocked, for example, via a valve in a set of control valves 180, as shown in Fig. 7 (wherein the fluid blocking valve is preferably incorporated into the main control valve set, although it could alternatively be a separate valve), or the motor 80 could be of the variable displacement type and its displacement set to zero. If a locked differential is required, then flow from the motor can be blocked via the main control valve 100 or 180, as shown in Figs. 1 and 7.
  • Case 1 Open Differential — Fig.2
  • the pump 90 is set at zero displacement.
  • the open diff — active diff control valve 110 is open to allow free flow from the motor 80.
  • Torque to the left and right axles 40 and 42 is equal and follows directly from the input torque. There is no torque reacted from the pump and motor because they are both spinning freely. Either output is capable of overspeeding during cornering, etc..
  • the main control valve 100 between the pump 90 and motor 80 is set such that the motor spins in the same direction as the pump. This creates an overspeed on the left output 42. This overspeed must be accompanied by an increase in torque on the left side (amount dependent on how much vectoring is required). This additional torque comes from the planet carrier 52, which comes directly from the motor torque. Motor torque also creates a torque at the ring gear 56, which follows through to the lay shaft 60. There is a torque split at the differential carrier 66; some torque goes through the differential 35 to the left and right outputs 40 and 42, and the remainder goes to the lay shaft torque.
  • the main control valve 100 between the pump 90 and motor 80 is set such that the motor spins in the opposite direction as the pump. This creates an overspeed on the right output 40. This overspeed must be accompanied by an increase in torque on the right side (amount dependent on how much vectoring is required). All torque to the right output comes from the differential carrier 66, so torque must be added to the differential carrier from the lay shaft 60. This is accomplished from the motor torque creating a torque in the ring gear 56 and then a torque in the lay shaft 60. At the same time the torque in the planet carrier 52 created by the motor torque takes away from the torque to the left output 42 coming from the differential 35. This leads to a decreased left output torque. Case 4: Locked Mode - Fig. 5
  • the main control valve 100 between the pump 90 and motor 80 is set such that flow from the motor is blocked and the motor 80 is locked. Therefore, both torque and speed is constrained to be equal to both axles 40 and 42.
  • the pump reacts no torque, and neither will the motor if both left and right outputs see equal torque. If one output sees a different torque from the other, (if it slips due to a different coefficient of friction, for example) a reaction torque is reacted by the motor, but since the motor is hydraulically locked, the input torque is split evenly between the left and right outputs, and left and right outputs are equal to carrier 66 speed. Input torque is split evenly between left and right output, and left and right output speeds are equal to carrier 66 speed.
  • the schematic control diagram in Fig. 6 illustrates some of the control inputs to a differential controller 175, such as left and right wheel speed, vehicle throttle position, steering position and movement, yaw sensors and other factors known to affect the control and traction of a vehicle, as well as pump displacement position feedback.
  • Control outputs from the controller 175 to the pump displacement control 97 and the control valve 100 enable rapid control of the operation of the differential between its various modes of operation and the degree of adjustment within the torque vectoring modes so as to optimize the driver's control of the vehicle in all conditions.
  • Controllers similar to the differential controller 175 are known in the art for controlling prior art limited slip differentials and torque biasing differentials, and the algorithms for governing the operation of the controller are also known, although they each are normally designed for a particular model of vehicle.
  • the hydraulic pump 90 In normal open differential operation, all of the power is routed through the standard differential 35 and there is no power routed through the planetset 50 and motor 80, which reduces parasitic losses.
  • the hydraulic pump 90 As the hydraulic pump 90 is always rotating at some ratio of input speed, it can also be used as a lubricating and cooling pump, and as a makeup pump for providing makeup fluid to the main pump/motor flow circuit 108, 109 and, via a line 120, for providing system pressure to operate the displacement control device 95, and providing lubrication pressure to a vehicle lubrication supply 125 via a restriction 130 (shown in Fig. 1), thereby negating the need for an additional pump.
  • the pump 90 is used as a lubrication pump, then it will be kept at least at a small displacement, and a valve 110, shown in Fig. 1, will be provided to block or limit the flow to the lubrication circuit from the pump, so that full pressure generated by the pump is available to drive the motor 80 when torque vectoring is required.
  • the lubrication flow blocking valve 110 or limiting regulator 112 (shown in Fig. 7) need only be a low flow valve, but it will need to operate against high pressure.
  • the valve 110 can perform this lubrication flow blocking function.
  • the planet set is of a 3:1 ratio and the lay shaft ratio is 1.5:1 therefore causing zero speed on the sun gear 55 in the straight-ahead case, shown in Fig.2.
  • the pump 90 is driven at the speed of the differential carrier 66, and the motor has an approximate ratio of 10:1 to the axle 42, therefore when the pump 90 and motor 80 are at the same displacement, there will be a 10% overspeed of one axle relative to the differential carrier 66.
  • the hydraulic connections can be made between the pump
  • FIG. 7 another embodiment of a vectoring differential is shown having a second planet set 150 to couple the ring gear 156 of the planet set 50 to the differential carrier instead of two spur gear pairs 70, 71 and 62, 64, as in the embodiment of Fig. 1.
  • This second planet set 150 allows the elimination of the two spur gears 62, 64 from the embodiment of Fig. 1, which are subjected to maximum output torque under maximum torque vectoring.
  • the duty cycle of the two spur gear pairs is low, the gears, shafts and bearings need to be big enough to handle this torque.
  • Using an additional planet set to carry this load offers a more compact differential package, as the shafts are concentric. The benefit of compact packaging can be important in some applications, as the space around these items is critical, since as there are typically a lot of suspension, chassis parts in this area as well.
  • the operation of the differential is the same as with the two gear pairs.
  • Fig. 8 a variation of the double planet set embodiment speed vectoring axle of Fig.7 is shown in a vehicle drive arrangement.
  • this variation has a conventional input drive shaft 30 driving an input bevel gear 32 of a conventional bevel gear differential 35 having a conventional differential carrier 66.
  • Right and left axles 40, 42 are driven by the differential 35 in a conventional manner.
  • both axle shafts are driven with the same torque and speed, as is usual with conventional differentials.
  • An epicyclic gear set 140 (the motor planet set) is coupled between the differential carrier 66, one axle 42, a hydrostatic motor 80 and hydrostatic pump 90.
  • the epicyclic gear set 140 includes a planet carrier 152 that carries a plurality of planet gears 154 in geared engagement between a sun gear 155 and a ring gear 256.
  • One axle (in the example shown in Fig. 8, it is the left axle 42) is coupled to one member of the epicyclic gear set 140.
  • the "one member” is the planet carrier 152, so the planet carrier 152 is driven at the rotational speed of the axle 42.
  • a second planet set (the reaction planet set 160) has one member (the sun gear 162 in the embodiment of Fig.
  • the sun gear 155 is coupled to a spur gear 184, which drives the hydrostatic motor 80 via gear 185 on one end of a motor idler shaft 187, and a motor drive gear 189 on the other end of the idler shaft 187 in the example shown in Fig. 8. Therefore, when the vehicle is in the straight ahead case, there is no rotation of the motor hydrostatic unit 80. When the vehicle goes around a corner and there is some speed difference between the axle 42 and the differential carrier 66, the motor hydrostatic unit 80 will be driven to rotate by that relative speed difference. The direction of rotation of the hydrostatic unit 80 will be dependent on which axle, the right axle 40 or the left axle 42, goes faster than the differential carrier 66.
  • a variable displacement hydrostatic pump 90 is driven via a pump idler gear 170 by the coupled third members 256/166 of the two planet sets 140 and 160.
  • the hydrostatic pump 90 will therefore always rotate at some fixed ratio of input speed.
  • the displacement of the pump 90 can be adjusted from zero to some maximum by way of a displacement control device, such as a hydraulic cylinder and piston 95 connected to the pump 90, and a pump displacement control valve 97, which can be electrically controlled by an actuator, such as a stepper motor 99 or the like.
  • the pump 90 is hydraulically coupled to the hydraulic motor 80 through main fluid flow circuit 108, 109, and the flow is controlled as shown by a main control valve 100, which is also electrically controlled by actuators 105, 106.
  • a pump displacement position sensor (not shown) may be used as in the embodiment of Fig. 1 to provide pump displacement position feedback to a controller 175, shown in Fig. 6.
  • the motor 80 When the pump hydrostatic unit 90 is adjusted to have some displacement and is being driven by the ring gear 256, and the main control valve 100 is positioned to conduct flow of hydraulic fluid between the pump 90 and the motor 80 through the main fluid coupling circuit 108, 109 as shown in Fig. 8, the motor 80 will be driven to rotate at a speed determined by the output of the hydrostatic pump 90. This will cause the axle 42 to rotate relative to the differential carrier 66. Since both axle shafts are connected to each other via the standard differential 35, as one axle rotates relative to the differential carrier 66, the other axle will rotate at the same speed but in the opposite direction relative to the differential carrier 66, therefore speed (and hence torque) vectoring will take place.
  • the amount of this speed vectoring will depend on the relative displacements of the pump 90 to the motor hydrostatic unit 80. Since the flow rate from the motor 80 is relatively small under normal cornering in open differential mode it is anticipated that the motor 80 could be a fixed displacement unit requiring just the displacement of the pump 90 and a control valve to be operated to effect torque vectoring.
  • the pump 90 could be either displaced through a positive and negative angle to achieve torque vectoring in either direction or (as shown in Fig. 1) the main control valve could switch the flow from the pump 90 to the opposite channels in the motor 80, making it possible for the pump 90 to be designed to stroke in one direction only. This may have benefits in reducing reaction times as it will require less time to activate the control valve 100 as opposed to stroking the pump 90 from a negative angle to a positive angle.
  • the motor 80 can either be hydraulically connected so that flow can freely pass from one side of the motor to the other or be blocked, for example, via a valve in a set of control valves 180, as shown in Fig. 7 (wherein the fluid blocking valve is preferably incorporated into the main control valve set, although it could alternatively be a separate valve), or the motor 80 could be of the variable displacement type and its displacement set to zero. If a locked differential is required, then flow from the motor can be blocked via the main control valve 100 or 180, as shown in Figs. 1 and 7.
  • Figs. 7 and 8 are similar, but there are some significant differences.
  • the control valves are slightly different.
  • Fig. 7 there are 2 three-way two-position solenoid valves 180 that are normally open so that pressure from the pump 90 connects to both ports of the motor 80, and the motor ports are blocked to the low pressure side of the pump 90.
  • both sides are normally open to the pressure side of the pump there is no pressure differential across the motor 80, so the motor is able to rotate freely in both directions without restriction and hence achieve an open differential state.
  • Activating one of the two valves 180 connects one port of the motor 80 to the low pressure side of the pump 90 whilst blocking that port from high pressure from the pump.
  • valve 180 As the other valve 180 is still in its open state there is now a pressure differential across the motor and therefore it will generate torque and hence cause torque vectoring. Depending on which valve is actuated, the differential will torque vector either left or right. To achieve a locked differential, the pump is used to "drive" the motor to zero speed. If wheel spin is causing the motor to rotate in a certain direction then the corresponding solenoid valve is actuated so that the pump pressure is used to counteract that motor rotation and hence keep the motor at or near zero speed.
  • One advantage of the embodiment of Fig. 7 is that the solenoid valves 180 are simpler and smaller, and have a quicker reaction time than the four way three position solenoid valve 100 used in the embodiment of Fig. 8. This should therefore decrease the response time of the differential.
  • the disadvantage is that the control system needs to drive the motor to zero speed in order to achieve a locked differential, whereas in the embodiment of Fig.8 the solenoid valve is actuated to a blocked position.
  • Fig. 9 The schematic of Fig. 9 is the same as Fig 8 with the exception that the pump 90 is driven directly from the common ring gear 356/366 as opposed to going thru the pump idler gear 170 of the embodiment of Fig. 8.
  • the pump and motor positions are reversed from the embodiment of Fig. 8 to package the hydrostatic units so that they mesh correctly with their respective gears, so the motor idler shaft 287 can be shortened.
  • displacement of the pump 90 is controlled by an electric motor actuator 195 that rotates a control shaft 196 that has an eccentric pivot 197.
  • the eccentric pivot 197 is connected to one end of a lever 198 that is connected to a pivot 199 on the pump 90, so that as the control shaft 196 is rotated by the electric motor actuator 195, the eccentric pivot 197 moves the lever 198 causing the pump 90 to articulate about it's pivoting axis, thereby changing its displacement.
  • the electric motor actuator can include a worm and wheel arrangement that will maintain the position of the pump when the electric motor is de-energized.
  • the differential includes a differential case 200 having a forward section 202 in which the input drive shaft 30 is journalled for rotation in bearings 204, 206 and 208.
  • the input shaft 30 ends in a bevel gear that meshes with the input bevel gear 32 of the bevel gear differential 35, as best shown in Fig. 12.
  • Right and left axles 40, 42 are driven by the differential 35 in a conventional manner.
  • the right axle 40 (shown in phantom) engages a spline 215 in the right hand bevel gear; the left hand axle 42 engages a spline (just barely shown in Fig. 12) in the left hand bevel gear in the differential 35.
  • a spline 215 in the right hand bevel gear
  • the left hand axle 42 engages a spline (just barely shown in Fig. 12) in the left hand bevel gear in the differential 35.
  • the epicyclic gear set 140 (the motor planet set) is coupled between the differential carrier 66, the left axle 42, the hydrostatic motor 80 and hydrostatic pump 90.
  • the epicyclic gear set 140 includes the planet carrier 252 that carries the plurality of planet gears 254 in geared engagement between the sun gear 255 and the ring gear 356.
  • the one axle 42 is coupled to the one member of the epicyclic gear set 140, the planet carrier 252, so the planet carrier 252 is driven at the rotational speed of the axle 42.
  • the second planet set (the reaction planet set 160) has one member (the sun gear 162) fixed to ground 163 (in this case, the differential case 200) with machine screws 222, and the second member (the planet carrier 164) connected drivingly to the differential carrier 66 via shaft 220 with machine screws 223, so that the third member (the ring gear 366) rotates at a fixed ratio of the differential carrier speed.
  • This third member 366 is connected drivingly to the second member (the ring gear 356) of the first planet set 140.
  • the gear ratio between the third member 366 of the reaction planet set 160 and the differential carrier 66 is chosen so that the ring gear 356 is driven to rotate relative to the planet carrier 252 at a speed such that the third member 255 of the epicyclic gear set 140 is stationary when the axle 42 and the differential carrier 66 are rotating at the same speed, as in the straight ahead case.
  • the sun gear 255 is splined to and drives an extension of the spur gear 284 which in turn is in geared engagement with the gear 285 on one end of the motor idler shaft 287.
  • the motor drive gear 289 on the other end of the motor idler shaft 287 is geared to the hydrostatic motor 80, as shown in Fig. 13. Therefore, when the vehicle is in the straight ahead case, there is no rotation of the motor hydrostatic unit 80. When the vehicle goes around a corner and there is some speed difference between the axle 42 and the differential carrier 66, the motor hydrostatic unit 80 will be driven to rotate by that relative speed difference. The direction of rotation of the hydrostatic unit 80 will be dependent on which axle, the right axle 40 or the left axle 42, goes faster than the differential carrier 66.
  • variable displacement hydrostatic pump 90 is driven directly by the coupled third members, the ring gears 356/366 of the two planet sets 140 and 160.
  • the hydrostatic pump 90 will therefore always rotate at some fixed ratio of input speed.
  • the displacement of the pump 90 can be adjusted from zero to some maximum by way of the displacement control device 195-197.
  • the pump 90 is hydraulically coupled to the hydraulic motor 80 through main fluid flow circuit 108, 109, and the flow is controlled as shown by a main control valve 100, which is also electrically controlled by actuators 105, 106.
  • a pump displacement position sensor 102 provides pump displacement position feedback to a controller (not shown) such as the controller 175, shown in Fig. 6.
  • the hydrostatic units 80 and 90 are positioned on opposite sides of a control body 300 so that the torque plates 310 and 312 of the hydrostatic units 80 and 90, respectively face each other across the control body 300, in a series configuration.
  • the large axial force exerted on the torque plates 310, 312 by the pistons 314 and 316 in the hydrostatic units 80 and 90 cancel each other out and place the control body 300 mainly in compression.
  • the control body 300 is mainly under a compressive load, the control body structure is inherently strong and stiff thereby reducing the size required to keep the control body faces flat and deflection free, which affords the best performance of the combination hydrostatic bearing.
  • the axial load between the hydrostatic units 80 and 90 is carried by links 320 coupled between yokes 325 that support the hydrostatic units 80, 90.
  • the links 320 are placed mainly in tension where they are inherently strong and stiff, thereby reducing the size of the structure taking this load.
  • These links 320 are rigidly connected to the control body 300, but the only loads that are placed upon the control body 300 from the links 320 are due to the imbalance of axial forces when the pump and motor hydrostatic units 80, 90 are at different displacements, and the radial loads that are induced from the yokes when the hydrostatic units are at angle other than zero degrees. The sum of these forces is equal to the reaction torques from the pump and motor hydrostatic units and these are the only loads that are imparted onto the supporting housing structure.
  • each of the disclosed vectoring axles can act as a standard open differential, a fully or partially locked differential, and vector torque and speed to either the left or right output, depending on the particular driving conditions of the moment, and under all conditions regardless of input torque. It can be used as a front, rear or center differential. It incorporates a standard type of differential gearset (bevel - planetary etc), and can incorporate an existing ring and pinion gear set - reducing production costs.
  • the incorporated standard bevel differential can carry the power under normal driving, and locked differential conditions. It needs only one or two planet sets, which carry input power only under torque vectoring conditions, so can be sized for only intermittent operation. The motor rotates only when there is differential speed between the input and either of the outputs, so the motor parasitic losses are low.
  • a control valve can be used to vary speed precisely from one axle to the other, thereby affording low reaction times.
  • the pump is rotating at a fixed ratio of input speed, so the pump, in addition to its primary function of driving the motor, can also be used for lubrication, cooling, and makeup flow, thereby negating the need for an outside pressure source.
  • both axle shafts are connected via a standard differential there is no need for any additional parking pawls.
  • Packaging, size and weight are within acceptable standards for current production vehicles.
  • the hydrostatic units are subjected only to the differential power of the vehicle, so the size and weight of the units required are relatively small, allowing the overall size and weight of the package to be kept within acceptable limits.
  • hydraulics are used to vector torque and for locking as opposed to the use frictional elements, the heat build up and wear of the components is significantly lower than existing types of torque vectoring axles making them suitable for high performance.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Retarders (AREA)

Abstract

cette invention concerne un essieu vectoriel hydraulique comprenant un différentiel entraîné par un arbre mu par un moteur et deux essieux entraînés par le différentiel. Le carter de différentiel est couplé à un élément d'un train d'engrenage épicycloïde, train d'engrenage dont un autre élément est relié à l'un des essieux et à un moteur hydrostatique. Le carter de différentiel est couplé à une pompe hydrostatique à cylindrée variable, laquelle est reliée hydrauliquement au moteur hydrostatique. Un système de commande gère la cylindrée de la pompe hydrostatique à cylindrée variable. La puissance provenant du moteur s'écoule pour l'essenteil du différentiel aux arbres de sortie. Le couple peut être transmis d'un essieu à l'autre par réglage sélectif de la cylindrée de la pompe de sorte qu'elle entraîne le moteur hydrostatique pour que la part de couple qu'il transmette à un essieu soit plus important que la part de couple transmis à l'autre essieu, la différence étant déterminée par le réglage de cylindrée de la pompe. La répartition requise du couple être les deux roues est déterminée par la commande de l'ordinateur à partir d'entrées de capteurs disposés dans le véhicule.
PCT/US2006/038017 2005-09-28 2006-09-28 Essieu vectoriel hydraulique Ceased WO2007038734A2 (fr)

Applications Claiming Priority (2)

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US72207505P 2005-09-28 2005-09-28
US60/722,075 2005-09-28

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017072329A1 (fr) * 2015-10-30 2017-05-04 Borgwarner Sweden Ab Dispositif de guidage de couple
CN111344156A (zh) * 2017-11-13 2020-06-26 奥迪股份公司 用于双轮辙车辆的车桥的驱动设备
CN113103826A (zh) * 2021-05-12 2021-07-13 吉林大学 采用双行星轮圆柱齿轮差速器的转矩定向分配电动驱动桥

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8300483D0 (en) * 1983-01-08 1983-02-09 Commercial Hydraulics Ltd Vehicle steering system
WO2004005754A2 (fr) * 2002-05-20 2004-01-15 Folsom Technologies, Inc. Differentiel d'orientation du couple hydraulique

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017072329A1 (fr) * 2015-10-30 2017-05-04 Borgwarner Sweden Ab Dispositif de guidage de couple
CN111344156A (zh) * 2017-11-13 2020-06-26 奥迪股份公司 用于双轮辙车辆的车桥的驱动设备
CN111344156B (zh) * 2017-11-13 2023-09-15 奥迪股份公司 用于双轮辙车辆的车桥的驱动设备
CN113103826A (zh) * 2021-05-12 2021-07-13 吉林大学 采用双行星轮圆柱齿轮差速器的转矩定向分配电动驱动桥
CN113103826B (zh) * 2021-05-12 2022-04-29 吉林大学 采用双行星轮圆柱齿轮差速器的转矩定向分配电动驱动桥

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