A hydrodynamic retarder device for installation in a driveline to a vehicle, wherein the retarder device comprises: a blade-equipped stator which, together with a blade-equipped rotor, forms a blade system with a workspace for receipt of an aqueous working medium, and a retarder circuit connected to the workspace to control the inflow of a working medium to the workspace, wherein the retarder circuit is installed to be connected to the vehicle's ordinary cooling water circuit. The retarder circuit comprises valve elements to shut off the flow of working medium to the workspace, and a negative pressure generator is connected in the retarder circuit, which is installed to reduce the pressure in the workspace to or below the vapor pressure for the working medium, so that the workspace is thus evacuated of the liquid working medium. The invention also pertains to a method and a vehicle.

A hydrodynamic retarder device for installation in a driveline to a vehicle, wherein the retarder device comprises: a blade-equipped stator which, together with a blade-equipped rotor, forms a blade system with a workspace for receipt of an aqueous working medium, and a retarder circuit connected to the workspace to control the inflow of a working medium to the workspace, wherein the retarder circuit is installed to be connected to the vehicle's ordinary cooling water circuit. The retarder circuit comprises valve elements to shut off the flow of working medium to the workspace, and a negative pressure generator is connected in the retarder circuit, which is installed to reduce the pressure in the workspace to or below the vapor pressure for the working medium, so that the workspace is thus evacuated of the liquid working medium. The invention also pertains to a method and a vehicle.

A system and method are provided for disabling a retarder during a gearshift at low speeds for improved driver comfort. These embodiments recognize that power flow is interrupted during a shifting process and use that opportunity to disable the retarder at low speeds, thereby eliminating an additional, uncomfortable jolt to the driver. Several embodiments are provided.

The present invention discloses a resistance force control structure of driven pulley device, which is pivot mounted on a wheel of a driven pulley device, and primarily uses damping oil or a magnetic force to achieve a resistance effect. The magnetic force portion can also be added to a gear structure to present another configuration of a resistance force control structure to achieve change in magnetic force to increase the stabilizing effect of a wheeled frame. Moreover, an adjustable mechanism enables the user to control changes in the height of the damping oil level or magnetic force strength to control the rotational speed of a wheel.

An outdoor grounds maintenance vehicle is self-propelled by a hydrostatic traction drive system that provides dynamic braking to the vehicle without the need for separate service brakes acting on the wheels of the vehicle. An engine kill device can be manually actuated by the operator to access the dynamic braking of the traction drive system by reducing the speed of the prime mover that powers the pump of the traction drive system. This provides an auxiliary braking system that can be used in an emergency or on demand by the operator in the event the accelerator pedal does not properly control the pump swashplates. The operator can control the rate at which the auxiliary brake system reduces the speed of the prime mover to zero.

The invention relates to a hydrodynamic retarder comprisinga rotor (1) and a stator (2) which form a working chamber (3) with each other;a first working medium connection (6);a second working medium connection (7); anda working medium container (4) that has an outlet (10), which is connected to the first working medium connection via a line, and an inlet (11), which is connected to the second working medium connection via a line; whereinthe working medium container is made of two housing parts (8, 9), which are joined together along a parting line (12). According to the invention:the two housing parts together enclose the working medium storage volume;one of the two housing parts simultaneously forms a part of a retarder housing (14) which supports or forms the stator and partly forms all or some of the working medium-conducting connections between the working medium storage volume and the working chamber; anda separating plate (13) is inserted between, the two housing parts, said separating plate together with one or both of the housing parts forming cavities for the working medium-conducting connections and/or the working medium storage volume.

The invention relates to a hydrodynamic retarder comprisinga rotor (1) and a stator (2) which form a working chamber (3) with each other;a first working medium connection (6);a second working medium connection (7); anda working medium container (4) that has an outlet (10), which is connected to the first working medium connection via a line, and an inlet (11), which is connected to the second working medium connection via a line; whereinthe working medium container is made of two housing parts (8, 9), which are joined together along a parting line (12). According to the invention:the two housing parts together enclose the working medium storage volume;one of the two housing parts simultaneously forms a part of a retarder housing (14) which supports or forms the stator and partly forms all or some of the working medium-conducting connections between the working medium storage volume and the working chamber; anda separating plate (13) is inserted between, the two housing parts, said separating plate together with one or both of the housing parts forming cavities for the working medium-conducting connections and/or the working medium storage volume.

A magnetorheological fluid brake and a control method therefor. When braking is not required, the brake does not work, and no field coils are energized. When braking is required and the brake receives a retarding braking signal, a field coil module is energized, the current is gradually increased, an oil port is gradually closed, and a back pressure inside the brake is also gradually increased, thereby gradually increasing a braking force so as to achieve a braking effect. By using the characteristics of a pump and the characteristics of a valve for the magnetorheological fluid, the viscosity of the magnetorheological fluid is adjusted, such that a back pressure is generated in a pump body, which in turn imposes a braking torque on a shaft, thereby performing braking.

A magnetorheological fluid brake and a control method therefor. When braking is not required, the brake does not work, and no field coils are energized. When braking is required and the brake receives a retarding braking signal, a field coil module is energized, the current is gradually increased, an oil port is gradually closed, and a back pressure inside the brake is also gradually increased, thereby gradually increasing a braking force so as to achieve a braking effect. By using the characteristics of a pump and the characteristics of a valve for the magnetorheological fluid, the viscosity of the magnetorheological fluid is adjusted, such that a back pressure is generated in a pump body, which in turn imposes a braking torque on a shaft, thereby performing braking.

A cooling circuit for a motor vehicle having a cooling medium pump that circulates a cooling medium in the cooling circuit having a hydrodynamic retarder. The cooling circuit further includes a main circuit in which the cooling medium pump and a drive motor of the motor vehicle, as well as a heat exchanger are positioned. A secondary branch of the cooling circuit includes a feed that branches off from the main circuit at a branch-off point and ends in the hydrodynamic retarder, and a return which proceeds from the hydrodynamic retarder and ends at a junction location in the main circuit. The return ends upstream of the branch-off location of the feed as viewed in a flow direction of the cooling medium in the main circuit, however on the same side of the cooling medium pump or at the branch-off location of the feed in the main circuit.