1883 results about "Propulsor" patented technology

The invention relates to the technical field of data processing, and discloses a propeller fault diagnosis and predictive maintenance method and system. The method comprises the following steps: collecting current, temperature, vibration and pressure signals of a propeller, extracting characteristic parameters to construct a time sequence data set, mapping the characteristic parameters into nodes, establishing a multi-physical field coupling hyperedge to construct a time sequence incidence matrix, inputting an encoder, extracting a degradation state characteristic vector, and mapping the degradation state characteristic vector into a health index; and calculating a degradation rate function in combination with the working condition parameters, and integrating the degradation rate function to predict the remaining service life. According to the method, the high-order coupling relation and the time sequence evolution characteristics among multiple parameters of the propeller are captured through the multi-physics field coupling hypergraph time sequence encoder, the influence of different operation conditions on degradation is quantified in combination with the degradation rate model sensitive to the working condition, and the problem that the fault evolution trajectory and the remaining service life cannot be predicted is solved; and an accurate time window reference is provided for predictive maintenance.

The invention discloses a decoupling control method for motion coupling between a track and a propeller, relates to the technical field of robot control, and realizes accurate and intelligent regulation and control of motion of a sea-land amphibious robot by constructing a complete closed-loop strategy from sensing, recognition, prediction to control. And the motion stability of the robot in a complex mixed environment is obviously improved. According to the method, the undesirable coupling effect between the crawler belt and the propeller can be anticipated and quantified in a prospective mode, suppression is conducted actively through self-adaptive control, impact, vibration and attitude instability caused by power conflicts in land and water transition or rugged terrain are effectively avoided, and stability and safety of a robot platform and loads of the robot platform are guaranteed. The energy utilization efficiency of the robot is greatly improved. And it is ensured that the two power systems work in the optimal cooperative state at any moment, and invalid energy internal consumption and redundant output are avoided.

An integrated hydrogen-electric engine includes, an air compressor system; a hydrogen fuel source; a fuel cell; an elongated shaft connected to the air compressor system or a propulsor; and a motor assembly disposed in electrical communication with the fuel cell, wherein the air compressor system includes a plurality of electrically driven compressors configured to run in series or parallel.

The invention discloses a hierarchical cooperative motion control method for a ship dynamic positioning and wave compensation embarkation system. The method comprises the following steps: acquiring historical motion data of a ship; the historical motion data of the ship are fused, and the current ship posture and speed are obtained; the prediction model generates a predicted value of the disturbance of the ship in the future preset time; extracting to obtain a low-frequency slow drift motion component; the total output force of the thruster is calculated, and the ship dynamic positioning system controls the thruster to work based on the total output force of the thruster so as to compensate the low-frequency slow drift motion component; a Stewart platform in the wave compensation embarkation system controls supporting legs to work based on the target lengths of the supporting legs so as to compensate low-frequency motion left after compensation of the ship dynamic positioning system and high-frequency motion which is not compensated; and residual disturbance after the Stewart platform is compensated is compensated through the gangway ladder. According to the invention, an energy distribution mode that low-frequency disturbance is compensated by a ship dynamic positioning system and high-frequency disturbance is compensated by a wave compensation embarkation system can be realized.

The invention discloses a variable-structure water-air amphibious robot and a motion control method. The robot comprises a water-air amphibious robot body, a variable-structure wing system and an electric control system. The robot body comprises a sealed cabin, a propeller fixing assembly, a fluid shell and a variable support tail cover. The variable-structure wing system comprises a driving gear transmission assembly, a two-section folding wing and a wing folding linkage assembly; the electric control system comprises a control core element, a visual module, a power supply module, a GPS module and an underwater depthometer module which are arranged in the cabin body; the motion control method is based on a deep reinforcement learning control method, control generalization ability is enhanced through teacher and student strategies and random domain, and the motion control method has more advantages in scenes such as inaccurate modeling and large external disturbance change. The structure of the variable-structure water-air amphibious robot integrates the structures of a rotorcraft, a fixed-wing aircraft, an underwater robot and the like, the modes of the wings can be switched, and efficient movement operation of the water-air amphibious robot is achieved.

The invention provides an ocean current interference resistant fault-tolerant control method and system for a robot multi-motor propulsion system, and the method comprises the steps: inputting the actual and expected position error and speed error of an underwater robot into a self-adaptive backstepping sliding mode path tracking controller, and obtaining the thrust needed by tracking motion; introducing a propeller weight matrix representing the fault degree of the propeller into a weighted pseudo-inverse method, optimizing the propeller weight matrix by adopting an intelligent algorithm to obtain an optimal propeller weight matrix, and performing thrust distribution on thrust required by tracking motion through the weighted pseudo-inverse method to obtain a thrust distribution result; according to the operation and thrust distribution results of the multiple motors, the parameters of all the motors are adjusted in a self-adaptive mode through a multi-motor fault-tolerant control strategy; and each motor remotely controls the underwater robot based on the parameters after self-adaptive adjustment, and obtains the actual position and speed of the underwater robot at the current moment for loop closing.

The utility model discloses a water area propeller and water area movable equipment. The water area propeller comprises a machine body, an operation device and a locking module. A propelling device used for outputting propelling force for propelling the water area carrier to move is arranged at the end of the machine body. The operation device is rotationally connected to the end, away from the propelling device, of the fuselage body through a transverse connecting shaft, can be folded or unfolded with the fuselage body and is used for being operated by a user to control the water area propeller to operate. The locking module comprises a first locking unit and a second locking unit, and the first locking unit and the second locking unit are arranged in the operation device and the machine body respectively. The operation device and the machine body are locked by the meshing force between the first locking unit and the second locking unit at the position between the transverse connecting shaft and the propelling device, and the operation device forms a suspension beam capable of loading the machine body between the transverse connecting shaft and the locking module.

The invention discloses a vibration type drain pipe crystal removal device, and particularly relates to the technical field of pipeline crystal removal, the vibration type drain pipe crystal removal device comprises a cylindrical main machine and a guide climbing frame, one end of the cylindrical main machine is in bolted connection with a propeller, and one end of the cylindrical main machine is provided with a crystal cleaning assembly used for layering and disintegrating crystals in a pipe; the crystal cleaning assembly comprises a conical guide frame and a driven guide ring frame which are movably connected to one end of the cylindrical main machine; a plurality of driving vibration rods and a plurality of driven vibration rods are respectively arranged outside the conical guide frame and the driven guide ring frame; according to the device, crystals in a pipeline are knocked in advance through the driving vibration rod and the driven vibration rod, the knocking target of the driving vibration rod and the driven vibration rod is a crystallization layer instead of a pipe wall, impact force is absorbed by the crystallization layer and does not directly act on a pipe wall body, and after the crystals are knocked to be loose, planing can be completed by the scraping tooth disc without applying too large force; and the scraping tooth disc further planes the fragments into fine chippings, so that the pipeline crystal removal efficiency is improved.

The invention discloses a method for predicting fluid excitation characteristics of a propeller, and relates to the field of propeller simulation. The method comprises the following steps: modeling a propeller flow field according to attribute information corresponding to the propeller flow field to obtain a propeller flow field grid model; determining a propeller flow field control equation corresponding to the propeller flow field grid model, and discretizing the propeller flow field control equation by adopting a finite volume method to obtain a discretized propeller flow field control equation; performing propeller hydrodynamic numerical simulation on the discrete propeller flow field control equation based on a delay separation vortex simulation method to obtain speed spatial-temporal distribution and pressure spatial-temporal distribution, and performing decoupling processing on the speed spatial-temporal distribution and the pressure spatial-temporal distribution; and according to the whirling vibration data, the vortex motion data, the decoupled pressure field and the decoupled speed field, the exciting force of the propeller flow field is obtained. The method can accurately reflect the influence of different vortex motions on the excitation characteristics of the propeller and the fluctuation of the velocity field of the propeller.

The utility model discloses a water area propeller and water area movable equipment. The water propeller is used for connecting a water carrier to propel the water carrier to move in the water. The water area propeller comprises a body and an operation device. A propelling device used for outputting propelling force for propelling the water area carrier to move is arranged at the end of the machine body. The operation device is rotationally connected to the end, away from the propelling device, of the fuselage body through a transverse connecting shaft, can be folded or unfolded with the fuselage body and is used for being operated by a user to control the water area propeller to operate. The operation device is provided with a first locking unit, the machine body is provided with a second locking unit, and when the operation device and the machine body are in a folded state, the first locking unit and the second locking unit lock the operation device and the machine body at the position between the transverse connecting shaft and the propelling device. And a suspension beam capable of loading the fuselage main body is formed between a locking position of the operating device between the first locking unit and the second locking unit and a connecting position of the operating device on the transverse connecting shaft.

The invention provides a ship path tracking and rolling comprehensive control method and device based on a straight-wing propeller, belongs to the technical field of ship motion control, and solves the technical problem that path tracking and rolling control precision and efficiency of a ship are insufficient due to environmental disturbance. Constructing a four-degree-of-freedom ship motion equation, constructing a four-degree-of-freedom ship motion model with interference and measurement noise, reconstructing a ship motion state by adopting a Kalman filter, calculating a path tracking error by utilizing a self-adaptive sight guidance algorithm, and generating an expected course angle; determining a longitudinal thrust, a rolling stabilizing moment and a course control thrust; and the revolution speed and the rotation swing angle of the straight wing propeller are optimized, and the rotation swing angle is recalculated. The method is suitable for the ship provided with the straight-wing propeller, and high-precision path tracking and efficient rolling stabilization are achieved by controlling the revolution speed and the swing angle of the propeller.

The invention relates to an array type underwater propeller with high maneuverability and low energy consumption, a pump jet generating device and a flow divider jointly form a propeller front end, an intelligent fluid director forms a propeller rear end, and the pump jet generating device drives an impeller through a rotating motor to drive surrounding water flow to rotate to generate a main jet flow; an isolation structure is arranged in the flow divider and used for evenly dividing the main jet flow into multiple strands of independent sub jet flows, and all the sub jet flows form propelling power after entering the intelligent flow guider to be guided. The intelligent fluid directors are connected with the flow channels of the flow divider in a one-to-one correspondence mode and used for converting fluid flowing out of the flow divider and out of the jet flow face into effective action jet flow with the adjustable flow speed. The intelligent fluid director comprises a jet flow end regulation and control mechanism and a pressure relief end regulation and control mechanism, and the jet flow end regulation and control mechanism is used for independently regulating the flow speed of effective jet flow ejected from the fluid director; and the pressure relief end regulation and control mechanism is used for maintaining the constant flow velocity at the inlet of the fluid director by releasing part of water flow when the effective jet flow velocity is regulated.

The invention discloses a quadruped robot anti-disturbance motion control method based on reinforcement learning and application, and belongs to the field of robot motion control. Firstly, a self-adaptive propulsion control frame is provided, and a propeller and a leg movement system of the quadruped robot are deeply fused. And secondly, through cooperative training of a double-encoder system (a teacher encoder and a student encoder) and a predictor, hidden state extraction and environment disturbance reconstruction are realized, so that the robot adjusts a motion strategy in real time under complex scenes such as actuator faults and water flow interference. And finally, in combination with multi-stage reinforcement learning training and privilege information utilization, strategy network output is optimized, and a speed and trajectory tracking task is completed. The motion robustness of the robot under unknown interference and damage conditions is remarkably improved through cooperative control of the propellers and the legs, anti-disturbance decision of hidden state driving and dynamic reward function design. The method is suitable for amphibious environments, can adapt to diversified disturbance scenes without additional fine adjustment, and has high practicability and reliability.

The invention discloses an underwater multi-mode mobile robot equipped with a flexible bionic gripper, which integrates three operation modes of propeller propulsion, six-foot crawling and target object grabbing, and realizes'movement-attachment-operation 'integrated collaboration. The robot main body adopts a five-thruster vector layout and has a five-degree-of-freedom motion capability; and six groups of three-degree-of-freedom mechanical feet and two groups of three-degree-of-freedom mechanical arms are arranged outside, and a cruising mode, a crawling mode or a grabbing mode can be automatically switched according to tasks. A coordination dual-network hydrogel bionic sucker and a flexible gripper are integrated at the foot end and the arm end, and controllable adsorption and desorption are achieved through a diaphragm pump. The control system generates a rhythm signal based on the central mode generator, and coordinates multi-module actions of paddles, legs and arms in combination with inverse kinematics solution. The robot is suitable for tasks such as wide water area cruising, complex terrain exploration, environment maintenance and seabed sampling, has high maneuverability and high integration degree, and provides an innovative platform for underwater fine operation.

The utility model discloses a water area propeller and water area movable equipment. The water area propeller comprises a machine body, an operation device and a locking module. A propelling device used for outputting propelling force for propelling the water area carrier to move is arranged at the end of the machine body. The operation device is rotationally connected to the end, away from the propelling device, of the fuselage body through a transverse connecting shaft, can be folded or unfolded with the fuselage body and is used for being operated by a user to control the water area propeller to operate. The locking module comprises a first locking unit and a second locking unit, and the first locking unit and the second locking unit are arranged in the operation device and the machine body respectively. The locking module locks the operation device and the machine body main body at the position between the transverse connecting shaft and the propelling device through the insertion force between the first locking unit and the second locking unit, and the operation device forms a cantilever beam capable of loading the machine body main body between the transverse connecting shaft and the locking module.

The invention relates to the technical field of underwater propeller modeling, and discloses an underwater propeller annular propeller modeling method based on analog simulation. The method comprises the following steps: constructing an initial blade fluid domain grid model by using a discrete element simulation algorithm based on three-dimensional geometric parameters and material attribute data of an annular propeller; after multiphase flow coupling boundary conditions are applied to the initial model, fluid dynamic load distribution data are obtained through a transient flow field solver; generating a blade deformation characteristic value according to the load data, and if the blade deformation characteristic value exceeds a preset tolerance interval, activating a dynamic grid reconstruction instruction; fluid-structure interaction interface pressure pulsation data is extracted based on the instruction, a stress concentration coefficient is calculated in combination with material attributes, and an abnormal signal is generated when a safety threshold value is exceeded; and when the signal is triggered, the vortex field tracking module is called to update the fluid domain grid model.

The invention belongs to the technical field of underwater propeller design, and discloses an annular propeller modeling and hydrodynamic performance evaluation method and system. The method comprises the following steps: defining a distribution rule of blade parameters along a wheelbase based on a segmented cubic Hermite interpolation method, and realizing parametric modeling; automatically generating a propeller three-dimensional geometric model and a flow field computational domain; carrying out discretization processing on the rotating domain and the outer watershed by adopting a hybrid grid technology; hydrodynamic performance data are obtained through numerical simulation calculation, and thrust, torque and efficiency coefficients are obtained through processing; and completing multi-working-condition performance calculation and drawing an open water curve by automatically and cyclically updating a speed coefficient, and finally storing design variables and performance response data into a database. According to the method, full-process automation from modeling, grid division, simulation calculation to post-processing is achieved, the efficiency of annular propeller design and hydrodynamic performance analysis is remarkably improved, and the labor cost and the time cost are greatly reduced.

The invention discloses a multi-parameter cooperative control underwater propeller turnover hoisting control method, particularly relates to the field of underwater propeller hoisting, and aims to solve the problem of unstable turnover control of a propeller under tidal current disturbance. The iteration interval of a high-risk section is compressed in time by means of self-adaptive step length mapping, then angle increment and target tension are synchronously corrected before the winding action by means of prediction correction circulation, and three-line linkage of angle adjustment, tension adjustment and environmental safety is achieved. The safety margin diagram is continuously refreshed under the driving of vibration and flow velocity dual information sources, and step length rollback is triggered once a node approaches a warning domain, so that potential oscillation is blocked in a germination stage. The synchronization reliability coefficient runs through the whole process, the winch synchronization quality is evaluated, real-time weighting is performed on step length mapping, and then a convergence path is kept close to a real balance channel. Therefore, the turning-over time is shortened, and the tension fluctuation amplitude is stabilized.

The application provides a weak fault feature extraction method for an autonomous underwater vehicle propeller, and belongs to the technical field of underwater vehicle fault diagnosis, and comprises two parts: fault feature enhancement and feature fusion. First, the application optimizes parameters by judging the Gaussianity of all modes of multi-source state signals and control signals through negative entropy, completes noise reduction, and extracts and enhances fault features based on a modified Bayesian algorithm. Then, the feature signals are divided into multiple time intervals, the faults occurring in each interval are taken as focal elements, all signals except the longitudinal velocity are subjected to first feature fusion, the first fusion result is subjected to second fusion with the feature signal of the longitudinal velocity, the fault features are further enhanced, and the monotonicity between the fault features and the fault degree is presented. The application can provide a basis for subsequent fault detection and identification, and is particularly suitable for state monitoring of autonomous underwater vehicle propellers.

Systems, methods, and devices include an aerial vehicle (AV) with a plurality of coaxially aligned vertical ducts. The lower vertical duct has a larger diameter than the upper vertical duct. Furthermore, the upper vertical duct at least partially contains a first propulsion component and the lower vertical duct at least partially contains a second propulsion component. The lower vertical duct can be coupled to the upper vertical duct by duct couplers which forms an air intake gap between the upper vertical duct and the lower vertical duct. The AV also includes one or more steering flaps disposed on the lower vertical duct, configured to manipulate an air flow out the bottom of the lower duct, thus controlling navigation and stability of the AV.

The utility model discloses a water area propeller and water area movable equipment. The water area propeller comprises a machine body, an operation device and a locking module. A propelling device used for outputting propelling force for propelling the water area carrier to move is arranged at the end of the machine body. The operation device is rotationally connected to the end, away from the propelling device, of the fuselage body through a transverse connecting shaft, can be folded or unfolded with the fuselage body and is used for being operated by a user to control the water area propeller to operate. The locking module comprises a first locking unit and a second locking unit, and the first locking unit and the second locking unit are arranged in the operation device and the machine body respectively. The suction force between the first locking unit and the second locking unit of the locking module locks the operating device and the fuselage body at the position between the transverse connecting shaft and the propelling device, and the operating device forms a cantilever beam capable of loading the fuselage body between the transverse connecting shaft and the locking module.

The invention belongs to the technical field of ionic wind propellers, and particularly relates to a multi-stage ionic wind propelling device with a common electrode structure, which comprises a plurality of ionic wind generating units which are sequentially arranged along the airflow direction, each unit consists of a conductive support structure and an ionization needle tip on the conductive support structure, and the ionic wind generating units are used for ionizing air under the action of a high-voltage electric field; the multiple units are isolated from one another through the insulation supporting structures and are connected in series, the power supply access module alternately provides positive and negative high-voltage power supplies for all the units, all the conductive supporting structures sequentially serve as ionization electrodes and receiving electrodes in a multi-stage electric field, and the electrode sharing type continuous acceleration structure is achieved. An independent receiving end does not need to be arranged for each stage, the number of electrodes and supporting parts is remarkably reduced, the ion acceleration path is prolonged, the thrust density is improved, a frame-type or non-frame-type structure can be adopted for flexible construction according to requirements, and the advantages of being light in structure, high in thrust-weight ratio and high in expansibility are achieved; the invention is suitable for the fields of micro aircrafts and directional air supply.

The invention provides an autonomous swing arm cooperative control method applied to an underwater dam body inspection robot, the inspection robot is equipped with a swing arm, an underwater propeller, a track moving mechanism and a multi-sensor system, and the method comprises the following steps: sensing and judging whether the inspection robot is stuck or not through multiple sensors in real time, and identifying the type of the inspection robot; calling a corresponding strategy from a cooperative control strategy set pre-trained by reinforcement learning based on the identified types such as sludge clamping stagnation, flexible winding or rigid obstacle; according to the strategy, expected parameters for controlling cooperative movement of a swing arm, a propeller and a crawler belt are directly generated and converted into specific driving signals, all executing mechanisms are driven to act cooperatively through an industrial communication protocol, and autonomous escape is achieved; through a sensing-decision-execution closed loop, self-adaptive cooperative control of multiple mechanisms in a complex underwater environment is realized, and the escape efficiency, the operation stability and the overall autonomy of the inspection robot are remarkably improved.

The invention belongs to the field of polymeric high-molecular polymer production equipment, and relates to a final polycondensation reactor for preparing a high-quality and high-viscosity PA66 polymer, the final polycondensation reactor comprises a shell and a stirring device located in the shell, and the shell is provided with a feed port, a discharge port and a gas phase port; the shell comprises an inner layer and an outer layer, and an area between the inner layer and the outer layer forms a jacket layer; the inner layer of the shell is composed of a cylinder I and a cylinder II, and the diameter of the cylinder I is larger than that of the cylinder II. One bottom surface of the cylinder I and one bottom surface of the cylinder II are intersected and overlapped areas are communicated with each other; the position of the feed port is higher than that of the discharge port; the stirring device consists of a transmission shaft and a stirrer; the first stirrer consists of a disc and a spiral belt fixed on the disc; the second stirrer comprises a spiral structural member; and the third stirrer comprises a spiral propeller. According to the invention, the continuous propulsion of the polymer melt in the final polycondensation process is realized, the backmixing of the high-viscosity polymer melt is prevented, and the retention time consistency of the polymer melt is improved.

The invention discloses a wing-shaped sail split floating aircraft and a flight control method thereof. The problems that an existing floating aircraft is large in energy consumption and complex in control mode are solved. The airfoil-shaped sail split floating aircraft comprises a ship-shaped main body, a plurality of sails are arranged on the upper portion of the ship-shaped main body, and a manned cabin is arranged on the lower portion of the ship-shaped main body; a power strip type air bag mechanism, a fixed type air bag mechanism and a lifting control air bag mechanism are arranged in the ship-shaped main body, a wind power propeller is arranged on the ship-shaped main body and provides thrust for steering and horizontal movement, and the wing-shaped sails provide assistance for horizontal flight. According to the ship-shaped aircraft, a large number of independent split helium-filled air bags are integrated into the ship-shaped aircraft body, and the flight safety coefficient is increased; the suspension of the aircraft in the air is realized through the balance weight of the power strip type variable air bag at a balance state critical value; the expansion volume change of the air bag is changed by pressing and releasing the air bag to control the lifting of the aircraft; through coupling of the control systems, the aircraft can fly safely, stably and flexibly with low energy consumption.

The invention provides an underwater robot and a control method thereof.The underwater robot comprises a robot body, a propelling mechanism arranged on the side face of the robot body and used for providing propelling force, and a processing mechanism in communication connection with the propelling mechanism and arranged in a closed space, the processing mechanism sends an operation instruction to the propelling mechanism so as to solve the problems that when the robot works in a narrow space (such as the interior of a net cage and between pipeline supports), the robot cannot counteract center-of-gravity shift through large-range maneuvering, and the robot is prone to collide with surrounding structures; and in a strong ocean current environment, frequent attitude correction further amplifies the risk of position drift.

The invention discloses a fuel cell-turbofan engine hybrid power system for a cross-medium aircraft, and relates to the technical field of aero-engines, the system comprises a solid oxide fuel cell, a turbofan engine, a lithium battery, an energy management module, a motor, a propeller, a reforming hydrogen production device and a medium self-adaptive oxidant supply subsystem. In an air flight mode, the system adopts autothermal reforming hydrogen production, a fuel cell and a turbofan engine to cooperatively work, a high-efficiency low-oil-consumption low-speed cruise and high-thrust acceleration mode is provided, and meanwhile, a lithium battery is charged. In the underwater submerging and water surface sailing mode, a turbofan engine flow channel is closed, steam reforming hydrogen production is adopted, a hybrid power system composed of a fuel cell and a lithium battery is used for driving a propeller, the fuel cell provides stable power, and the lithium battery meets the instantaneous high-power requirement. The system solves the problems that a traditional power system is low in efficiency, poor in cruising ability, single in working mode and the like.

An example aircraft includes a parallel propulsion unit, the parallel propulsion unit comprising: a propulsor configured to provide forward propulsion of the aircraft; a gas turbine engine configured to drive the propulsor; an electrical machine configured to generate, for output via one or more electrical busses, electrical energy using mechanical energy derived from the gas turbine engine; and a power sharing module configured to control a ratio of the mechanical energy used to drive the propulsor and used to generate electrical energy; and a plurality of series propulsion units, each series propulsion unit comprising a respective propulsor of a plurality of propulsors that are configured to provide vertical propulsion of the aircraft and a respective electrical machine of a plurality of electrical machines, each respective electrical machine configured to drive a respective propulsor of the plurality of propulsors using electrical energy received from one or more electrical busses.

A marine drive includes a torpedo housing having an open end and an electric motor assembly with an electric motor configured to power a propulsor for propelling the marine drive in water. The electric motor assembly includes a motor housing which is nested in the open end such that such that a first portion of the motor housing extends into the torpedo housing and such that a second portion of the motor housing extends from the torpedo housing and is exposed to the water for cooling thereof. The torpedo housing defines an opening which partially exposes the first portion of the motor housing to the water for cooling thereof.

A marine drive assembly is configured for propelling a marine vessel in a body of water. The marine drive assembly may include a drive unit having a propulsor for generating a thrust force in the body of water, a mounting bracket for mounting the drive unit to the marine vessel, the mounting bracket having an exterior facing portion outside the marine vessel and an interior facing portion inside the marine vessel, and a heat exchanger configured to exchange heat between water from the body of water and a cooling fluid for cooling a component of the marine drive assembly, wherein the heat exchanger is coupled to the exterior of the mounting bracket.