3020 results about "Flywheel" patented technology

The invention discloses a vehicle idling start and stop control system and method. The control system judges whether a vehicle has idling start and stop conditions by monitoring the water temperatureof an engine, the capacity of a storage battery, a safety belt and other information, judges whether the vehicle has conditions of stopping the engine by monitoring the rotating speed of the engine, the speed of the vehicle, the brake air pressure and other conditions, and judges whether the vehicle has conditions of starting the engine by monitoring the gear of a gearbox, the speed of the vehicle, a hand brake and other information. When the relevant conditions are met, start and stop work signals are sent to the engine though a CAN bus. In order to guarantee the reliability of frequent startand stop of the engine, the system strengthens flywheel gear rings of a starter and the engine. In order to ensure that the battery does not lose power, a storage battery capacity sensor is added tothe system on the basis of increasing the capacity of the storage battery, and the idling start and stop are allowed when the state of charge (SOC) of the storage battery satisfies a safe starting threshold. The idling start and stop control system has advantages of low cost and high reliability, and is especially suitable for commercial vehicles.

The invention relates to the technical field of power supply devices, in particular to an energy-saving optimization method for an electric energy storage device, and the method comprises the steps: fusing a lithium ion battery solid-liquid phase change kinetic equation, a flow battery fluid mechanics equation and a flywheel rotor rigid-flexible coupling equation through a neural differential equation; constructing a dynamic meta-knowledge base containing cross-time scale nonlinear interaction features; performing dynamic parameter compensation on the polarization voltage hysteresis effect and the electrolyte flow resistance coupling effect by using a physical information neural network to generate a decoupled residual feature vector; according to the method, multi-physics field coupling modeling is achieved through the dynamic meta-knowledge base, and the energy efficiency optimization effect of the energy storage device is improved by combining the physical information neural network and the quantum optimization algorithm.

A freewheel adjustable wheel of the present invention comprises: a rotary gear unit that is rotated by receiving power from a pedal part and is provided with a gear along the outer circumference thereof; a case part that supports the rotary gear unit to be rotatable; a clutch bearing that transmits the power to the case part when the rotary gear unit rotates in the forward direction; a clutch hub that rotates together with the rotary gear unit; clutch gears installed on the clutch hub and fixed to the case part; and a drive unit that supplies rotational power; and a moveable gear unit moved by means of the power of the driving unit.

A crossbow with a de-cocking crank mechanism having sprockets preferably includes a cranking mechanism, which utilizes a clutch sprocket and clutch assembly axial to a drive gear, and a one-way bearing axial to a bearing sprocket to cock a crossbow. The clutch assembly includes a clutch sprocket, a flywheel surface, a friction disc, and a pressure plate. The use of a one-way bearing may control the rotation of the drive unit used to wind (take-up) an elongated connecting device. Functional properties of a crank mechanism for the winding and unwinding of the elongated connecting device such as a rope, chord or the like device for pulling a secondary object from a first position to a second position are well known in the art.

The present invention relates to a flywheel (1) for a drive train of a motor vehicle, comprising a main flywheel mass (4) forming an input side (2) which can be screwed to a crankshaft of an internal combustion engine through a plurality of screw holes (5) distributed in the circumferential direction (U) of the flywheel (1), a slip clutch (6) arranged downstream of the main flywheel mass (4) in a torque transmission path emanating from the input side (2), and a torsional vibration damper (7) arranged downstream of the slip clutch (6) in the torque transmission path and which has both an output flange (11) and a hub (8) forming an output side (3), which is connected in a rotationally fixed manner to the output flange (11), with through holes (10) distributed in the circumferential direction (U), wherein the torsional vibration damper (7) has a disassembly device (12) which can be removed by rotation and which is designedto remove the non-rotatable connection of the hub (8) to the output flange (11) so that the through holes (10) can be aligned with the screw holes (5).

The invention discloses a methanol generator flywheel assembling device and method, and relates to the technical field of generator flywheel assembling. The flywheel assembling device comprises a lifting seat, a clamping seat is mounted at the top of the lifting seat, a first oil tank is mounted below the outer side of the clamping seat, a clamping assembly is mounted at the top of a piston rod in the first oil tank, a first corrugated pipe and a second corrugated pipe are connected to the bottom of the first oil tank, and a hammering seat is mounted at the top of the lifting seat. A hammering block is longitudinally and slidably installed on the side edge of the top of the hammering base, a telescopic connecting rod is rotatably installed at the center position of the bottom of the hammering block, the bottom end of the telescopic connecting rod is rotatably connected with the bottom of the hammering base, a hammering assembly is installed on the side wall of the hammering base, and a moving assembly is installed on the inner wall of the bottom of the hammering base. A traditional manual hammering flywheel installation mode is replaced, the flywheel installation efficiency is improved, the labor cost is reduced, and the labor intensity of workers is relieved.

The invention discloses a collaborative enhancement energy consumption mechanism and a support arm type fan tower drum damping device with the collaborative enhancement energy consumption mechanism, and relates to the technical field of engineering structure vibration, the collaborative enhancement energy consumption mechanism comprises a liquid column lever assembly and a plurality of inerter damping units symmetrically installed at the end of the liquid column lever assembly, and each inerter damping unit comprises a shell; the hydraulic damper and the linear-rotation converter are sequentially and axially installed in the shell from top to bottom, when the liquid column inclines, the first connecting plate is driven to drive the piston rod to stretch out and draw back, the piston rod drives the flywheel to rotate through the linear-rotation converter, and therefore vibration energy is transmitted to a fixed foundation structure through the second connecting plate to be dissipated; the invention further discloses a supporting arm type fan tower drum vibration reduction device, displacement of the vibration transmission part is transmitted to the liquid column lever through the connecting piece, the inerter damping unit is driven to stretch out and draw back, a complete energy consumption chain of the tower drum, the vibration transmission part, the connecting piece, the liquid column, the inerter damping unit and the ground is formed, and it is guaranteed that energy is stably transmitted to a fixed foundation structure.

The invention relates to the technical field of power systems, provides an electricity price and energy storage joint optimization method and system in an electricity market environment, and aims to solve the problem that in the prior art, deep cooperation between electricity price and energy storage and a market mechanism is difficult to achieve. The method comprises the steps of obtaining actual and predicted load data of a power grid, and generating load prediction error distribution of a power market; according to load prediction error distribution, actual and predicted load data of the power grid and available rotation kinetic energy of the composite flywheel array, active power compensation is carried out on power shortage of the power grid; acquiring a real-time electricity price signal of each transaction period in the power grid, and generating a dynamic charging and discharging threshold value; generating a dynamic charging and discharging strategy of the energy storage equipment based on the dynamic charging and discharging threshold value; and based on the compensated power and a dynamic charging and discharging strategy, suppressing the electricity price fluctuation of the power vacancy generation node. According to the invention, suppression of instantaneous electricity price suddenly rising and market fluctuation closed-loop control are realized, and the problems of physical response delay and market strategy separation are synchronously solved.

The invention belongs to the technical field of mechanical test tool equipment, and particularly relates to an electro-hydraulic speed regulator test testing device. Comprising the steps that a virtual diesel engine model generates a signal and supplies the signal to a rotating speed controller, an alternating current power supply supplies power to a frequency converter to drive a motor to operate, and the rotating speed of the motor is transmitted to an electro-hydraulic speed regulator through a first coupler to drive a main pump in the electro-hydraulic speed regulator to build pressure; a hydraulic bridge circuit in the electro-hydraulic speed regulator acts to drive the output shaft to rotate, the output shaft transmits an output signal back to the virtual diesel engine model through the flywheel, the magnetic powder brake and the angle sensor, and the virtual diesel engine model feeds back the signal to the magnetic powder brake through the brake controller; and the output torque of the electro-hydraulic speed regulator is ensured to meet the operation requirement and is confirmed by the torque sensor. The electro-hydraulic speed regulator test device has the advantages that the electro-hydraulic speed regulator test device is provided with the outer circulation oil way, and the test requirements of various electro-hydraulic speed regulators can be met.

Narrow vehicles have multiple advantages but tend to have a limited application because they are roll unstable. The use of flywheels to increase their stability is a known method but the operation range, complexity, performance and cost usually limit the application of these vehicles. Stability and agility enhancement system and method enabling the application of stabilizing forces from flywheels and the steering of the trajectory concurrently and cooperatively with the driver's steering and assistance enable the benefit of reduced cost and complexity while providing enhanced performances, intuitive control, safety and operation range.

The present disclosure discloses a can opener with an adaptation function, including a shell assembly; a circuit board and a speed reduction transmission assembly which are separately arranged in the shell assembly; an eccentric assembly movably penetrating through the shell assembly, wherein the eccentric assembly is in meshing and transmission connection with the speed reduction transmission assembly; an integrated knife flywheel penetrating through the shell assembly and detachably arranged on the eccentric assembly, wherein the integrated knife flywheel includes an integrally formed integrated knife flywheel main body, a resisting slot body, and a cutting tool body; the knife flywheel main body is in a slope design; the resisting slot body is an annular slot; the cutting tool body is a ring tool.

The invention discloses an aircraft landing gear shimmy test bed and a test method, the aircraft landing gear shimmy test bed comprises a main body rack, a hanging basket system, a large flywheel, a flywheel driving system, an excitation device and a follow-up displacement measurement system.The aircraft landing gear shimmy test bed can simulate the shimmy of an aircraft after undercarriages of different design configurations are subjected to interference excitation force or interference torque in the process of takeoff, taxiing, landing and the like of the aircraft; the control effect of the shimmy damping system on the stability of the undercarriage has short excitation time so as to simulate real working conditions, the shimmy stability performance of the undercarriage can be accurately detected, excitation is continuously carried out under the condition that the test state is continuously changed, and the working efficiency is greatly improved. The follow-up displacement measuring system designed by the invention can enable the exciting force and the center of the axle to be always kept on the same horizontal plane, can apply torque control and torque excitation control, is suitable for undercarriage shimmy tests with different axle heights, different tire diameters and different excitation modes, and has certain universality.

The invention discloses a control method of a hybrid energy storage system and the hybrid energy storage system, and relates to the technical field of hybrid energy storage systems.The control method comprises the steps that corresponding simulation control parameters of the hybrid energy storage system under different operation conditions are obtained, and the simulation control parameters are parameters used for simulating the characteristics of a battery cluster; and controlling the operation state of each energy storage converter according to the simulation control parameters. By adopting the method, the flywheel can be controlled to simulate the characteristics of the battery to work, the cost of the hybrid energy storage system can be effectively reduced, and the complexity of the control process of the hybrid energy storage system is reduced.

Certain embodiments provide a power tool comprising a motor including a flywheel, an inertial measurement unit (IMU) configured to output IMU data, and a controller coupled to the motor and the IMU. The controller is configured to process the IMU data to generate processed IMU data, detect, based on the processed IMU data, whether the power tool has been moved in a pickup motion that is associated with an imminent use of the power tool, and increase a speed of the motor to a target speed in response to the detection.

The invention belongs to the technical field of inertia friction welding of high-temperature alloy thin-wall parts, and particularly relates to a homogenized grain type inertia friction welding device and method. The device comprises a base, an inertia friction welding rotation driving mechanism, a supporting shaft assembly, a synchronous vibration and shaping coupling mechanism and an inertia friction welding axial feeding mechanism, and the inertia friction welding rotation driving mechanism, the supporting shaft assembly, the synchronous vibration and shaping coupling mechanism and the inertia friction welding axial feeding mechanism are arranged on the base. The output end of the inertia friction welding axial feeding mechanism is connected with the fixed chuck, and inertia friction welding is conducted on workpieces on the upsetting side and the rotating side through axial feeding. One end of the supporting shaft assembly is connected with the base, the other end of the supporting shaft assembly is rotationally connected with the flywheel, and the supporting shaft assembly is used for supporting and preheating workpieces. The synchronous vibration and shaping coupling mechanism is arranged on the outer side of the welding seam area and used for conducting deformation suppression and grain refinement control on the welding seam area. According to the method, joint grains are refined uniformly, the forming precision is high, near-net forming is achieved, and the production efficiency is high.

The invention discloses a flywheel and gravity hybrid energy storage system and method based on clutch mechanical coupling. The system comprises a high-speed inertia flywheel, a flywheel protection cover, a speed-increasing gearbox, a flywheel pit, a flywheel main shaft, a load-bearing fixing foundation, a bearing, a coupler, a motor, an equipment fixing device, an electromechanical detection device, a speed-reducing gearbox, a lifting system, a first high-speed clutch, a second high-speed clutch and an intelligent control unit. According to the invention, the quick response characteristic of the high-speed flywheel and the large-capacity advantage of gravity energy storage can be fully utilized to realize flexible switching of the high-speed flywheel and the gravity energy storage in different operation modes, and the closed state of the clutch is dynamically adjusted through the intelligent control unit, so that the frequency modulation, peak regulation and inertia support performance of a power grid is optimized; meanwhile, mechanical wear and energy loss are reduced, and the overall operation efficiency and reliability of the system are improved.

The invention discloses a power generation and driving integrated device with an active lubricating system. The power generation and driving integrated device comprises a motor shell, a motor, a planetary gear mechanism, a transmission gear set, a filter, an electronic pump, a flywheel shell and a motor shell cover plate. The motor shell comprises a motor cavity for accommodating the motor and a gear cavity for accommodating the planetary gear mechanism and the transmission gear set, the flywheel shell seals the gear cavity, and the motor shell cover plate seals the motor cavity; the bottom of the gear cavity is divided into an oil suction cavity through a motor shell oil separation rib, an oil return groove is formed in the connecting position of the motor shell oil separation rib and the bottom of the gear cavity, the filter is contained in the oil suction cavity, the electronic pump partially stretches into the oil suction cavity and is connected with the filter, and an oil outlet of the filter is communicated with an oil inlet of the electronic pump. According to the invention, stable active lubrication of parts with lubrication and cooling requirements, such as shafts, gears, bearings, motors and the like, is realized. Meanwhile, gear oil stirring can be reduced, and the speed reducer efficiency is improved.

The invention belongs to the technical field of power system operation and motors, and particularly relates to an energy storage type phase modifier control method which comprises the steps that a rotating shaft of a double-fed motor is connected with a flywheel to serve as an energy storage type phase modifier; the rotor winding is connected to a power grid through an excitation system and a transformer in sequence, and the excitation system is electrically connected by a reactor, a back-to-back converter and a filter in sequence; the stator winding is directly connected to a power grid; the control system decouples reactive power and active power, vector control is carried out on exciting current to absorb or release power, and reactive power-voltage support and active power-frequency support of the power grid are completed. The method overcomes the defects that a traditional direct-current excitation phase modulation mode can only modulate phase and cannot modulate frequency, or is cumbersome and slow in response. The system can meet the requirement of wide-range variable-speed operation, quickly store / release a large amount of rotor kinetic energy, inhibit the voltage and frequency fluctuation of a power grid, and is especially suitable for stations with high new energy occupation ratio. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

An energy-saving rolling support and radial symmetric hydraulic cylinder drum type intelligent braking structure of a screw press comprises a motor, the motor is fixed to an upper cross beam, an output shaft of the motor is connected with a gear, the gear is meshed with an outer ring gear on a flywheel, the flywheel and a first screw are connected and rotate together, and the top of the first screw is tensioned through a first nut; hydraulic cylinders are symmetrically arranged above the upper cross beam in the radial direction, hydraulic oil enters cavities of the hydraulic cylinders through oil conveying pipelines on the upper cross beam, advancing and retreating of piston push rods are achieved, drum brakes are installed on the front portions of the piston push rods, friction plates are symmetrically arranged on the end faces of the drum brakes, and when the piston push rods are ejected out, the friction plates make contact with the lower end faces of flywheels. Therefore, the braking of the screw rod mechanism is realized; according to the invention, the space is saved, and the braking sensitivity is improved; the friction loss of the screw press in the operation process is reduced, and the energy utilization rate is increased.

The invention provides a flywheel unloading method based on an electric pushing mechanical arm in a position protection period. The flywheel unloading method comprises the steps that a joint corner combination is selected when the thrust direction is in a position protection allowable range; the control torque under the joint rotation angle combination of each mechanical arm is determined, and an initial table look-up matrix is established; determining an optimal torque and a torque error allowable range; according to the control torque, the optimal torque and the torque error allowable range, grade division is conducted on the joint corner combination; constructing a cost function according to the optimal torque and the control torque; on the basis of grade division, the smaller the cost function is, the higher the priority of the joint corner combination is; selecting a joint corner combination with the highest priority from the initial look-up table matrix, performing permutation and combination of joint corners around the joint corner combination in a fine step length manner, determining a corresponding control moment, forming a second-order look-up table matrix, and selecting a joint corner combination with the highest priority; and circularly selecting the joint corner combination with the highest priority to obtain a final joint corner combination.

A computer system has processing circuitry to selectively operate the powertrain system in at least a freewheeling mode, in which an output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels. The processing circuitry is further configured to: determine an opportunity for the freewheeling mode by predicting a feasibility of restarting the engine along an intended route by using a controllable clutch. Predicting the feasibility of restarting the engine by using the controllable clutch includes determining fulfillment of any one of a first restarting condition and a second restarting condition. Determining fulfillment of the first restarting condition includes comparing current total weight of the vehicle with a threshold value indicative of a minimum total weight for avoiding excessive braking of the vehicle during restarting at a high friction road condition with a given total gear ratio. Determining fulfillment of the second restarting condition includes comparing a current drive axle load with a corresponding threshold value indicative of a minimum drive axle load on a drive axle for avoiding excessive wheel slip during restarting at a low friction road condition with a given total gear ratio. The powertrain system is controlled into the freewheeling mode upon the fulfillment of any one of the first restarting condition and the second restarting condition.

A gyroscopic roll stabilizer includes an enclosure, a flywheel assembly, a bearing, a motor, and a bearing cooling circuit. The enclosure is mounted to a gimbal for rotation about a gimbal axis and configured to maintain a below-ambient pressure. The flywheel assembly includes a flywheel and flywheel shaft. The bearing rotatably mounts the flywheel assembly inside the enclosure for rotation about a flywheel axis. The bearing has an inner race and an outer race. The inner race is rotationally fixed relative to the flywheel shaft, and the outer race is held rotationally fixed relative to the enclosure. The motor is operative to rotate the flywheel assembly. The bearing cooling circuit is configured to transfer heat away from the bearing by recirculating coolant along a closed fluid pathway. The gyroscopic roll stabilizer is configured to transfer heat away from the inner and / or outer race of the bearing to the coolant.

A flywheel (1100) comprising a plurality of discs (1102) arranged in a stack (1104), including at least first and second end discs at either end of the stack (1104), each of the plurality of discs (1102) including a plurality of disc apertures therethrough, first and second plate members (1106) disposed at opposing ends of the stack (1104), one or both of the first and second plate members (1106) including a plurality of plate apertures (1106a) therethrough for alignment with a corresponding series of disc apertures through the stack (1104), in which one or both of the plate members (1106) includes one or more recesses (1106c) which are disposed on a disc-facing side thereof and positioned adjacent to one or more of the plurality of plate apertures (1106a), and connection means (1114) for clamping the first and second plate members (1106) together about the stack of discs, the connection means (1114) extending through each of the plurality of disc apertures, in which a spacer or space-filling means (1138) is provided between the or each connection means (1114) and the respective disc apertures for supporting the connection means (1114), the spacer or space-filling means (1138) extending from a position within the stack (1104) into the one or more recesses (1106c) of one or both of the plate members (1106).

The invention discloses an electric inertia simulation braking power test bench and an electric inertia control method thereof, and relates to the technical field of electric transmission simulation of flywheels, the electric inertia simulation braking power test bench comprises a motor, an incremental encoder, a main shaft, a flywheel, a force arm frame, a mechanical friction braking torque sensor, an electric transmission control system and a brake disc; an incremental encoder is installed at the rear end of the motor, the transmission end of the motor is connected with the main shaft through a coupler, the flywheel is installed on the main shaft, a brake disc is installed on the force arm frame, and meanwhile the force arm frame is connected with a mechanical friction braking torque sensor. According to the invention, the angular speed, the angular displacement and the mechanical friction braking torque are synchronously collected, and the motor torque is calculated and given, so that the test bench operates in a state of approaching an equivalent flywheel and equivalently having no system resistance; the algorithm can control the total error within a very small range; accurate matching of rotational inertia is achieved, and the control precision can meet the high-precision test requirement. And investment and operation cost are saved.

A system for deploying a payload from an aerial vehicle onto a target surface includes a flywheel-stabilized delivery device that is detachably couplable to the aerial vehicle. The delivery device includes an axle, a flywheel, and a payload holder. The delivery device may additionally include an attachment portion and a floatation device. The payload holder may be detachably coupled to the payload such that the delivery device detaches from payload upon impact at the target surface. The system may additionally include a release mechanism for detachably coupling the delivery device to the aerial vehicle. The release mechanism may include a flywheel driver, a receiver, and a dropper device. The release mechanism may be remotely controlled by an operator to release the delivery device from the aerial vehicle.

The invention relates to a self-adaptive force output and energy consumption bridge vibration and vibration control inerter tuning device, and belongs to the technical field of vibration control. Comprising a roll shaft support, a spring rod, a main inerter element, a box chamber main body, a secondary inertia flywheel, a flow guide pipe, a transmission connecting rod and a flow baffle, the main inerter element penetrates through and is arranged in the box chamber main body, the outer end of the main inerter element is connected with the spring rod, the spring rod is connected with the roll shaft support, and the roll shaft support is respectively fixed with the bottom surface of a main beam and the top of a bridge pier; in addition, the flow guide pipe is arranged in the box chamber body, a flow baffle and a transmission connecting rod are further arranged in the flow guide pipe, and the transmission connecting rod is further connected with a secondary inertia flywheel. The damping device is achieved through a hydraulic mechanism, and the damping device with the self-adaptive inerter coefficient is formed through linkage of the inerter devices in the main box chamber and the auxiliary box chamber, so that the purposes of changing the inerter coefficient in real time and damping are achieved. The shock resistance, the transmission efficiency, the energy consumption effect, the structural rigidity and the stability of a vibration reduction system can be improved.

A rotary drive assembly of an electric nail gun, comprising a support seat configured on a gun frame, an inner-rotor brushless DC motor and a flywheel configured inside the support seat in a coaxial manner. Along an assembly axial direction, the support seat is formed with a motor housing chamber to house the brushless DC motor and a flywheel housing chamber to house the flywheel, the two chambers being separated from each other. The motor housing chamber is formed with an axial port for assembly and heat dissipation of the brushless DC motor. The flywheel housing chamber is formed with a radial port to expose part of the flywheel outside the support seat. The axial port is perpendicular to the radial port. The invention can simplify the structure of the rotary drive assembly and facilitate its assembly and heat dissipation.

The invention relates to a cable feed device (1) for a robot (2), comprising: - a rotatably drivable first cable drum (8); - a rotatably mounted second cable drum (9), wherein the cable drums (8, 9) are at least indirectly connected to a first segment (4); - a deflection roller (14), which is operatively connected to a second segment (5) pivotably arranged about an axis of rotation (24) relative to the first segment (4); - a cable (6), which is wound on the deflection roller (14) and the free ends of which are each fastened to one of the cable drums (8, 9); and - a first freewheel (15) and a second freewheel (16) which are operatively connected to the deflection roller (14), wherein the first freewheel (15) moves into a coupling state when the deflection roller (15) is rotated in a first direction of rotation, wherein the second freewheel (16) moves into a coupling state when the deflection roller (14) is rotated in a second direction of rotation counter to the first direction of rotation, and wherein a cable feed drive (17) with a transmission ratio not equal to 1 is operatively arranged between the first freewheel (15) and the second segment (5) or between the second freewheel (16) and the second segment (5). The invention also relates to a robot (2) having such a cable feed device (1).

The invention relates to the technical field of flywheel and battery hybrid energy storage control, and discloses a quick power response and energy management method of a flywheel and electrochemical hybrid energy storage system. The method comprises the following steps of: acquiring flywheel rotating speed, kinetic energy allowance, battery end voltage and internal resistance in real time to form a state vector, performing consistency correction on an initial power decomposition instruction according to the state vector, and generating a final power instruction matched with unit real-time capability. Meanwhile, by monitoring the change trend of the flywheel kinetic energy and the battery charge state, a power decomposition coefficient is dynamically adjusted according to a preset coordination rule, and the power decomposition coefficient is fed back to an initial decomposition link to form closed-loop control. According to the method, accurate matching of the power instruction and the dynamic characteristics of the energy storage unit is realized, and the safety and accuracy of system response are improved; and through closed-loop trend adjustment, the long-acting adjustment capability and operation stability of the system are maintained.

A flywheel (100) comprising a plurality of discs (102) arranged in a stack (104), including at least first and second end discs at either end of the stack (104), each of the plurality of discs (102) including a plurality of disc apertures (102a) therethrough, first and second plate members (106) disposed at opposing ends of the stack (104), one or both of the first and second plate members (106) including a plurality of plate apertures (106a) therethrough for alignment with the plurality of disc apertures (102a) in the first and second end discs respectively, connection means (114) for clamping the first and second plate members (106) together about the stack (104) of discs (102), the connection means (114) extending through each of the plurality of disc apertures (102a) without contacting the plurality of discs (102).