Patent Application
20150225990
The disclosure relates generally to a damper that tolerates vibrations.
Dampers absorb energy. Dampers can absorb the energy of one component moving relative to another component. For example, dampers absorb energy of a vehicle hood closing relative to a chassis of a motor vehicle. The dampers control the rate at which the hood descends to a closed position.
Dampers may be exposed to vibrations. The vehicle hood can vibrate relative to the chassis when the motor vehicle is driven, for example. Vibrations can damage dampers. Dampers in large vehicles are especially prone to such damage due to the high vibratory amplitudes.
A vibration tolerant damper according to an exemplary aspect of the present disclosure includes, among other things, an outer tube, a shaft received within the outer tube, and a piston valve received within the outer tube. The shaft can move independently from piston valve as the shaft as the shaft extends and retracts relative to the outer tube.
In another example of the foregoing vibration tolerant damper, the shaft moves together with the piston valve as the shaft extends and retracts through a first range relative to the outer tube, and the shaft can move independently from piston valve as the shaft as the shaft extends and retracts relative to the outer tube through a second range.
In another example of the foregoing vibration tolerant damper, the first range is greater than the second range.
In another example of any of the foregoing vibration tolerant dampers, the movement of the shaft through the first range is damped by the piston valve, and movement of the shaft through the second range is undamped by the piston valve.
In another example of any of the foregoing vibration tolerant dampers, the movement of the shaft through the first range is damped, and movement of the shaft through the second range is undamped.
In another example of any of the foregoing vibration tolerant dampers, the dampers include a retainer that moves the piston valve with the shaft when the shaft extends relative to the outer tube within the first range, the retainer secured to the shaft.
In another example of any of the foregoing vibration tolerant dampers, the vibration dampers include an area of the shaft having a reduced diameter relative to a primary body of the shaft. The piston valve is received over the area and the primary body moves the piston valves with the shaft when the shaft retracts relative to the outer tube within the first range.
In another example of any of the foregoing vibration tolerant dampers, the dampers include an orifice plate that moves with the piston valve.
In another example of any of the foregoing vibration tolerant dampers, the dampers include damping fluid within the cylinder that moves through openings in the piston valve to damp movement of the shaft through the first range.
In another example of any of the foregoing vibration tolerant dampers, the first range is more than 12 times greater than the second range
In another example of any of the foregoing vibration tolerant dampers, the shaft extends and retracts through a second range relative to the outer tube in response to vibrations.
In another example of any of the foregoing vibration tolerant dampers, the shaft is securable to a first component, and the tube is securable to a second component. The vibration is vibration of the first and second component relative to each other.
In another example of any of the foregoing vibration tolerant dampers, the first component is a vehicle hood and the second component is a vehicle chassis.
A method of damping components according to an exemplary aspect of the present disclosure includes, among other things, moving a piston valve together with a shaft as the shaft extends and retracts through a first range relative to an outer tube. The movement of the piston valve damping movement of the shaft, and moving the shaft relative to the piston valve as the shaft extends and retracts through a second range relative to an outer tube.
In another example of the foregoing method, moving the piston valve together with the shaft moves the piston valve though a hydraulic damping fluid within the outer tube to damp movement of the shaft.
In another example of any of the foregoing methods, the piston valve receives an area of the shaft having a reduced diameter relative to a primary body of the shaft portion.
In another example of any of the foregoing methods, movement of the piston valve over the area is limited on a first axial side by a retainer that is fixed to the shaft, and on an opposing second axial side by a primary body of the shaft.
In another example of any of the foregoing methods, the method includes providing lift assist to the components using the shaft.
A method of damping movement of a component according to an exemplary aspect of the present disclosure includes, among other things, damping movement of a shaft relative to an outer tube to slow movement of component from an open position to a closed position, and permitting undamped movement of shaft relative to the outer tube when the component is in the closed position.
In another example of the foregoing method, the method includes moving a piston damper through a damping fluid during the damping and not moving the piston damper through the damping fluid during the undamped movement.
In another example of any of the foregoing methods, the component is a hood.
The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows.
Referring to
When the vehicle hood 24 is in the closed position of
In some examples, such as large trucks, relative movement between the vehicle hood 24 and the vehicle chassis 28 can be as high as +/−10 millimeters. This vibrational movement, if not accounted for, can exert high forces and significant heat on the dampers and cause very high mechanical forces that are transferred into the mounting hardware of the damper creating high stresses and mechanical failures
During damping, the vibration tolerant damper assembly 10 creates a resistive force that controls the speed of the vehicle hood 24 moving to the closed position of
Although the example vibration tolerant damper 10 functions primarily to damp movement of the vehicle hood 24, a person having skill in this art and the benefit of this disclosure would understand that the vibration tolerant damper includes other types of dampers, such as those dampers that also provide a lift assistance. In such dampers, the movement of a single damper assembly would control the speed at which the vehicle hood 24 closes and also provide assistive force to facilitate moving the vehicle hood 24 to an open position.
Referring now to
As the vehicle hood 24 moves between open and closed positions, the shaft 46 extends and retracts relative to the outer tube 40.
As the vehicle hood 24 moves from the fully open position of
The piston valve 50 receives an area 78 of the shaft having a reduced diameter. The area 78 is reduced in diameter relative to the remaining primary portion 82 of the shaft 46. The transition or shoulder 86 between the area 78 and the primary portion 82 is what causes the piston valve 50 to move through the hydraulic fluid 74 as the shaft 46 retracts within the outer tube 40. Retraction of the shaft 46 as the vehicle hood 24 closes causes the shoulder 86 to push against the orifice plate 58, which then contacts the piston valve 50 to force the piston valve 50 through the hydraulic fluid 74.
Referring now to
When the shaft 46 is in a neutral and closed position as shown in
In this example, movement of the vehicle having the vehicle hood 24 may induce vibrations causing the vehicle hood 24 to move relative to the vehicle chassis 28 even though the vehicle hood 24 is closed and latched. Vibrations can move the vehicle hood 24 closer to the vehicle chassis 28 causing the shaft 46 to retract further into the outer tube 40 as shown in
As the vibration oscillates in another direction, the shaft 46 extend from the outer tube 40 as shown in
Notably, the piston valve 50 and orifice plate 58 are not directly attached to the shaft 46. The orifice plate 58 and piston valve 50 are free to move along the area 78 of the shaft 46 relative to the shaft 46.
Because the piston valve 50 and orifice plate 58 are free to move relative to the shaft 46 when the vehicle hood 24 is closed, the piston valve 50 does not damp movement of the shaft 46 relative to the outer tube 40 when the vehicle hood 24 is closed.
Vibratory movement of the vehicle hood 24 relative to the vehicle chassis 28 is movement within a second range less than the first range of movement. The extent of the example second range are shown by
When the vehicle hood 24 is moved by an operator, for example, from the closed position, the shaft 46 extends out from the outer tube. The extending movement of the shaft 46 exceeds the range of movement permitted within the second range.
The retainer 54 thus contacts the piston valve 50 and pulls the piston valve 50 through the hydraulic fluid 74 as the vehicle hood 24 moves to the fully opened position of
Notably, because the initial movement of the vehicle hood 24 when opened is through the second range, this movement is not damped as. During the initial movement shaft has not extended far enough to pull the retainer 54 into contact with the piston valve 50. Thus, efforts to open the vehicle hood 24 are not supplemented by damping from the piston valve 50. The damping occurs once the shaft 46 has extended to a position where the retainer 54 contacts the piston valve 50.
Referring to
The extending movement of the shaft 46 is damped due to the movement of the hydraulic fluid 74 through openings within the piston valve 50 and, in this example, the retainer 54. The fully extended shaft 46 compresses at least one spring 96 at an end of the outer tube 40 opposite the end having the at least one spring 90.
When moving from the fully opened position of
Referring to
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.
