Hydraulic damping valve

Patent metadata

Field	Value
Publication number	US-10774894-B2
Application number	US-201815869232-A
Country	US
Kind code	B2
Filing date	Jan 12, 2018
Priority date	Jan 13, 2017
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A damping valve for a hydraulic damper comprises a valve housing comprising an inlet chamber and an outlet chamber. A valve seat is arranged between the inlet chamber and the outlet chamber. A valve element having a cylindrical first portion is slidably received in a cylindrical bore of the valve housing. A second portion of the valve element has a valve surface for selectively engaging and disengaging the valve seat to allow passage of hydraulic fluid between the inlet chamber and the outlet chamber. A spring element is mounted within the valve housing for biasing the valve element into engagement with the valve seat.

First claim

The invention claimed is:

1. A damping valve for a hydraulic damper, comprising:
a valve housing comprising an inlet chamber and an outlet chamber and containing a hydraulic fluid;
a valve seat arranged between the inlet chamber and the outlet chamber
a valve element having a cylindrical first portion slidably received in a cylindrical bore of the valve housing and a second portion having a valve surface for selectively engaging and disengaging the valve seat to allow passage of hydraulic fluid between the inlet chamber and the outlet chamber;
a spring element mounted within the valve housing for biasing the valve element into engagement with the valve seat;
the bore of the valve housing having a closed end defining a bore chamber between an end of the first portion of the valve element and the closed end of the bore;
at least one passage providing fluid communication between the bore chamber and the inlet chamber when the valve element is in engagement with the valve seat;
at least one axially extending channel formed in a radially inwardly facing surface of the bore, a first end of the channel opening into the inlet chamber and a second, opposed end being selectively exposed or closed by the first portion of the valve element as it slides in the bore to selectively communicate the channel with the bore chamber, wherein
the at least one axially extending channel is closed by the first portion of the valve element as the valve surface of the second portion of the valve element approaches the valve seat such that the hydraulic fluid may pass from the bore chamber to the inlet chamber only through the at least one passage, whereby a higher damping force is exerted on the valve element such that the valve surface of the second portion of the valve element engages the valve seat relatively softly.

2. A damping valve as claimed in claim 1 , wherein the at least one passage comprises at least one axially extending passage formed in the valve element and extending from a first aperture formed at the said end of the first portion of the valve element to at least one second aperture which communicates with the inlet chamber.

3. A damping valve as claimed in claim 1 , wherein the at least one passage comprises at least one passage extending through the valve housing.

4. A damping valve as claimed in claim 2 , wherein the at least one passage through the valve element comprises a central passage which extends axially along the longitudinal axis (A) of the valve element.

5. A damping valve as claimed in claim 4 , wherein the central passage further comprises at least one section extending at a non-perpendicular angle to the longitudinal axis from an end of the axial passage to the second aperture.

6. A damping valve as claimed in claim 1 , wherein the first and second portions of the valve element are connected by a third, smaller diameter section around which the inlet chamber is arranged.

7. A damping valve as claimed in claim 1 , wherein the second end of the axially extending channel has a chamfer such that the radial depth (d) of the axially extending channel decreases progressively at the second end of the axially extending channel.

8. A damping valve as claimed in claim 1 , comprising a plurality of the axially extending channels in the radially inwardly facing surface of the bore.

9. A damping valve as claimed in claim 8 , wherein the axially extending channels are equispaced circumferentially around the circumference of the bore.

10. A damping valve as claimed in claim 9 comprising a pair of diametrically opposed channels.

11. A damping valve as claimed in claim 1 , further comprising one or more axially spaced channels extending circumferentially around an external surface of the first portion of the valve, each axially spaced channel extending completely around the circumference of the external surface of the first portion of the valve element.

12. A hydraulic damper comprising:
a piston arranged for reciprocating movement within in a cylinder and dividing the cylinder into first and second fluid chambers;
a first damping valve as claimed in claim 1 ;
a first fluid passage fluidly connecting the first fluid chamber to the inlet chamber of the first damping valve; and
a second fluid passage fluidly connecting the second fluid chamber to the outlet chamber of the first damping valve.

13. A hydraulic damper as claimed in claim 12 further comprising:
a second damping valve as claimed in claim 1 ;
a third fluid passage fluidly connecting a first fluid chamber of the cylinder to the outlet chamber of the second damping valve; and
a fourth fluid passage fluidly connecting a second fluid chamber of the cylinder to the inlet chamber of the second damping valve.

14. A helicopter rotor system comprising a hydraulic damper as claimed in claim 12 and a helicopter rotor, the helicopter rotor being coupled to the piston of the hydraulic damper.

15. A damping valve as claimed in claim 5 , comprising a plurality of said sections, each extending to a respective second aperture.

16. A damping valve as claimed in claim 15 , wherein the said sections and second apertures are arranged symmetrically around the axis (A) of the valve element.

17. A damping valve as claimed in claim 7 , wherein the at least one second aperture is formed in a fillet joining the first and third sections of the valve element.

Assignees

• Hamilton Sundstrand Corp
• Hamilton Sunstrand Corp

Inventors

• Jaśkiewicz Zbigniew

Classifications

• F16F9/49

  Stops limiting fluid passage, e.g. hydraulic stops {or elastomeric elements inside the cylinder which contribute to changes in fluid damping (fluid-actuated displacement devices with means for accelerating or decelerating the stroke F15B15/22)} · CPC title

• F16K17/0433

  with vibration preventing means · CPC title

• F16F9/483

  characterised by giving a particular shape to the cylinder, e.g. conical · CPC title

• F16F9/512

  Means responsive to load action, {i.e. static load} on the damper or {dynamic} fluid pressure {changes} in the damper, {e.g. due to changes in velocity (F16F9/504, F16F9/516 take precedence; non-automatic damper adjustment from a distance using servo control, the servo pressure being created by the flow of damping fluid F16F9/465; self-pumping fluid springs in vehicle suspensions B60G17/044)} · CPC title

• B64C27/51

  Damping of blade movements · CPC title