GB2389637A

GB2389637A - A fluidic rotary damping device which includes a rotatably mounted wiper disposed in a fluid-filled chamber

Info

Publication number: GB2389637A
Application number: GB0213260A
Authority: GB
Inventors: Ralph Stuart Norman; Dennis Patterson
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-10
Filing date: 2002-06-10
Publication date: 2003-12-17
Anticipated expiration: 2022-06-10
Also published as: GB2389637B; GB0213260D0

Abstract

A fluidic damping device 1 comprises a rotatably mounted wiper 7 that sealingly moves past the sidewalls 3, 4, bottom 6 and peripheral wall 5 of a chamber 2 of the housing as well as a faceplate 8 attached to the top of the housing. The housing contains a bypass channel 9 that has first and second ports 10, 11 in the first and second sidewalls 3, 4 respectively of the chamber 2. A control shaft 12 is rotatably mounted within the housing 1 and has indentations of varying sizes 13 formed at distinct points A, B, C, D, B, F about its outer diameter, the shaft being so located in the housing that either no indentation or a single indentation lies within the bypass channel 9 at a given time to variably restrict the flow of fluid therethrough. In an alternative embodiment a continuous groove of increasing cross-sectional area replaces the discrete indentations, and extends around most of the circumference of the shaft.

Description

FLUIDIC DAMPING DEVICE

( I FIELD OF THE INVENTION

2 This Invention relates to a fluid damping device, which may be used for example 3 to damp a force that tends to move the plane of rotation of a steerable wheel or wheels 4 of a vehicle having a shaft used to steer such wheel or wheels away from being generally 5 parallel to the frame of such vehicle. It also may be used in other steering devices, such 6 as a ski of a snowmobile or the exhaust Jet of a personal watercraR, that uses a shaft or 7 the like in the steering process.

8 DESCRIPTION OF THE RELATED ART

9 United States patent number4,773,5 14 for a Hydraulic Damping Device discloses 10 a wing 23 or the casing 6 is rigidly attached to a portion of a motorcycle that rotates with I I the fork that holds the front wheel of a motorcycle The other of these two elements, ie, l 2 either the casmg 6 or the wing 23 is rigidly connected to the frame of the motorcycle 13 Therefore, whenever the front wheel of the motorcycle is turned to the left or right, there 14 will be relative motion between the wing 23 and the casing 6.

I The chamber 11 Is sealed to prevent the leakage of a fluid and is filled with 16 hydraulic fluid. The wing 23 Is "dimensioned to fit sealingly to the bottom part 12, the l 7 cover 13 and the inside of the peripheral wall 10c" so that hydraulic fluid cannot pass 18 around the wing 23. Movement of the wing 23 is, consequently, impeded by the 19 hydraulic fluid, thereby dampening the turning left and right of the front wheel 20 The degree of dampening is controlled with a channel 24 in the cover 13 for the 21 casing 6. The channel 24 has ports near the sides 10a, 10b of the chamber 11 which 22 permit hydraulic fluid to flow around the wing 23. The effective cross-sectional area of 23 channel 24 Is controlled by a screw 27 that by being turned Is Inserted farther into 24 channel 24. The farther screw 27 is inserted into channel 24, the smaller is the effective 25 area of channel 24 and the greater is the impedance to the flow of hydraulic fluid and, 26 therefore, the dampening.

27 As the knob 29 which turns the screw 27 is moved radially, a spangloaded ball 28 33 fits mto a number of circumferentially distributed bores 32 having a smaller diameter

( 1 than the ball 33 to "facilitate proper setting" of the screw 27 Still, it Is difficult; 2 precisely to determine the degree to which the screw 27 has intruded within the 3 channel 24 and, therefore, the degree of dampening that will be achieved.

4 Moreover, a somewhat complex system employing two valve balls 34, 35 5 and a pressure spring 42 which maintains the balls 34, 35 in their open positions ' 6 until the flow of hydraulic fluid, caused by a rapid turning of the front wheel, 7 forces one or the other of the balls 34, 35, depending upon the direction of the 8 turn, closed. Unfortunately, contaminants, such as those created through the wear 9 of parts in the Hydraulic Damping Device, can cause such a valving system to 10 stick. l I I Additionally, bypass channels 25 and 26 eliminate dampening near the 12 centre of chamber 11 by allowing hydraulic fluid to flow from the centre to the 13 sides of chamber 11 The extent of the central area where dampening has been 14 eliminated is determined by rotating a sleeve to align one of the several different l 5 openings 56 a, b, c, d and 57 a, b, c, d with one of several different connecting 16 ports47a,b,c,dand48a,b, c,d 17 Having all ports for the bypass channels in the cover 13, however creates l 8 the possibility that when the wing 23 is near either side 1Oa or side Lob, the wing 19 will either be farther toward such side 1Oa or 10b than Is any port or will be 20 under the port closest to such side lea or rob. Because the wing 23 is 21 "dimensioned to fit sealtngly to the bottom part 12, the cover 13 and the inside 22 of the peripheral wall 1Oc" so that hydraulic fluid cannot pass around the wing 23 23, either of these possible situations will preclude hydraulic fluid from being 24 transferred to the side of the wing 23 that is toward the nearer side 10a, 10b and 25 thereby impede the proper functioning of the wing 23.

26 The angular size of the chamber 11 Is not specified. From Figure 2, 27 however, it appears to be substantially less than 180 degrees.:

SUMMARY OF THE INVENTION

The present invention provides a fluids damping device comprising a chamber in which a wiper is rotatably mounted for movement in said chamber in sealing contact with walls of said chamber a bypass conduit communicating with portions of said chamber on opposite sides of the wiper and a rotary control valve disposed in said conduit, the angular position of the control valve controlling the extent to which the bypass conduit is occluded. In one form, the control valve may comprise a shad) having a plurality of fluid pathways angularly spaced around the shaft to effect said controllable occlusion.

The fluid pathways may be of different sizes to each other, and are disposed so that only one pathway at a time communicates with the bypass conduit.

The pathways may be formed by indentations in the surface of the shaft.

In another form the control valve comprises a shaft having a groove of increasing cross-sectional area to effect said controllable occlusion.

The groove may extend around a major portion of the circumference of the shah Preferably the cross-sectional area of the groove Increases linearly with angle around the shaft.

There may be a local recess in a wall of the chamber to permit fluid to pass around the wiper at a predetermined angular position thereof relative to the chamber The angle of movement of the wiper in the chamber may be as much as 180 In one embodiment the device comprises a housing containing a generally sector-

shaped chamber having a

1 first side wall, a second side wall, a peripheral wall, a bonom, and a rotatably mounted wiper. A faceplate Is sealngly mounted to the top of the housing, and the wiper has 3 dimensions such that it sealingly moves past the faceplate, the bottom of the housing, and 4 the peripheral wall of the housing.

s There is, a single bypass channel, and it is contained within the housing, rather than 6 in the faceplate. Moreover, the bypass channel Is kept as simple as possible by containing 7 no valving. This eliminates the possibility of a container causing such a valve to stick.

8 The bypass channel has a first port in the first side wall, preferably near the 9 peripheral wall, and a second port in the second side wall, preferably near the peripheral 10 wall. Near the first port, the first side wall may contain an extension that Is made simply 11 to accommodate the tool that create the chamber in the housing If this is done by grinding 12 or drilling ] 3 Having the ports in the side walls ehminates the possibility that the wiper can be so 14 close to a side wall that no fluid can be transferred to the side ofthe wiper that is nearer to 15 that side wall 16. The amount of damping in this embodiment is controlled by having indentahons of 11 varying sizes formed at distinct points around a control shaft situated so that either or, 18 indentation or only one indentation lies within the bypass channel at a given time.

I 9 Moreover, each ndentahon in the shaft Is aligned with a detent in the bottom side of a knob 20 attached to the top of the shaft. A spring Is placed in a vertical corridor in the housing, 21 which vertical corridor is closed at the bottom. A ball is placed atop the spring so that it 22 presses against the bottom of the knob. The size of each detente is sufficiently large that 23 the ball entering a detente is very perceptible to one turning the knob. Also, a unique visual 24 Indicator, preferably a numeral, is placed above each detente. Therefore, a user knows 25 precisely the size of the indentation that is in the bypass channel and, therefore, the degree 26 of dampening of dampening that will occur

( If the knob is stopped between detents, no indentation will be within the bypass channel, ie., the bypass channel will be completely closed so that damping Is at a maximum. In a second embodiment, rather than having discrete indentations a continuous indentation is cut around the shah in such a manner that for a first sector of the shaft there Is no indentation in the shaft and then the indentation commences and becomes increasingly deeper as it progresses around the shaft until the continuous indentation stops upon reaching the first sector. One detent exists above the first sector and one above the groove immediately preceding its end, ie., above the deepest portion of the groove; thus, the damping is continuously adjustable.

Grooves are placed in the bottom ofthe faceplate at desired locations to select areas where there will be no damping because the viscous fluid, preferably hydraulic oil, that will be placed in the chamber can flow around the wiper as the wiper turns. This is much simpler than the bypass channels of United States patent number 4,773,514 and, consequently, less prone to being clogged by contaminants.

The location of such grooves is selected at the time of manufacture and is, preferably, symmetrical about the center of the chamber and extends to each side wall of the chamber, leaving an area in the centre of the chamber where darnpmg will occur.

Finally, the sector of the chamber in the device of United States patent number 4,773,514 covers only approximately ninety degrees, whereas the sector of the chamber In the present device can be much larger, preferably approximately one hundred twenty degrees. s

( BRIEF DESCRIPTION OF THE DRAWINGS

The Invention will be described merely by way of example with reference to the accompanying drawings, wherein: Figure I is a cutaway view of a housing of a device according to the invention.

Figure 2 shows the control shaft.

Figure 3 is a section through the shah showing the indentations.

Figure 4 is a plan view of the device.

Figure 5 is a side view of the device..

Figure 6 shows the bottom of the faceplate.

Figure 7 is a lateral view of the wiper.

Figure 8 is a plan view of the wiper.

Figure 9 is a plan view of the knob.

Figure 10 shows a control shaft of a second embodiment of the invention, and Figure 1 1 is a section through the shaft of figure 10 on line 11-11.

1 DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referrmg to figures l to 9, a fluid damping device according to the invention, l 3 comprises a housing 1 having a generally sector-shaped chamber 2 with a first side wall 3, 4 a second side wall 4, a peripheral wall 5, a bottom 6, and a rotatably mounted wiper 7 (figs 5 7,8). A faceplate 8 is sealingly mounted to the top of the housing 1 And, as discussed 6 above, the wiper 7 has dimensions such that it sealingly moves past the faceplate 8, the 7 housing 1 at the bottom 6 of the chamber 2, and the peripheral wall 5 of the housing 1.

The housing 1 contains a bypass channel 9 having a first port 10 in the first side wall 9 3, preferably near the peripheral wall 5, and a second port 11 in the second side wall 4, 10 preferably near the peripheral wall 5.

I l A control shaft 12 (figs. 2 and 3) has indentations 13 of varying sizes formed at 12 distinct points around the shaft 12 with areas having no indentation 13 between each 13 consecutive pair of indentations 13 and, as mentioned above, is so located in the housing 14 I that either no indentation or only one indentation 13 lies within the bypass channel 9.

15 a given time. Of course, the control shaft 12 is rotatably mounted in the housing I and 16 completely blocks the bypass channel 9 when no indentation 13 has been rotated into the 17 bypass channel 9 18 A knob 14 (fig 9) is attached near the top 15 of the shaft 12 In the bottom 16 of I 9 the knob 14 are detentes 17. Each indentation 13 in the shaft 12 is aligned with a detent 17.

20 Moreover, the housing 1 contains a vertical corridor 18 which is closed at the bottom IS.

21 A spring 20 is placed in the vertical corridor 18 so that it rests on the bottom 19. A ball 21 22 is located atop the spring 20 in such a position that it presses against the bottom 16 of the 23 knob 14 and will enter the various detentes 17 as the knob 14 is rotated. The size of each 24 detente 17 is sufficiently large that the ball 21 entering a detent 17 is very perceptible to one 25 turning the knob 14 Additionally, a unique visual indicator 22, preferably a numeral, is 26 placed above each detent 17.

27 The bottom 23 of the faceplate 8 (fig. 6) contains grooves 24 so that the viscous 28 fluid, preferably hydraulic fluid, which is placed in the chamber 2 can flow above the wiper 29 7 as the wiper 7 is rotated. Optionally, the portion ofthe housing 1 which forms the bottom 30 6 ofthe chamber 2 could contain the grooves 24. Preferably, there are two grooves 24; and 31 such grooves 24 are preferably located symmetrically about the center 25 of the chamber 32 2 The grooves 24 preferably extend to each side wall 3, 4 of the chamber 2, leaving an 33 area in the center 25 of the chamber 2 where dampening will occur.

I The sector of the chamber 2 preferably covers one hundred twenty degrees ' :{ The end of the wiper 7 (fig. 7) about which the wiper 7 rotates Is cylndacally shape I 3 and extends above and below the wiper blade 26. A depression 27 In the bottom 23 of the 4 faceplate 8 contains the top 28 of the cylindrical portion 29, and the bottom 30 of the 5 cylndncal pOniOn 31 extends through an aperture 32 in the housmg 1 at the bottom 6 of 6 the chamber2.

7 An arm 33 (figs. 4,5) having a first end 34 is rigidly attached near such first end 34 8 to the cylindrical portion 29 near the bottom 30 of the cylindrical portion 29 9 Preferably, the second end 35 of the arm 33 is rigidly attached to the frame of a 10 vehicle on which the Fluidic Dampening Device is used, and the housing 1 is Wildly 11 connected to a portion of the vehicle that rotates when the steering device, such as a front 12 wheel or wheels, is fumed to steer the vehicle. Alternatively, however, the second end 35 13 of the arm 33 Is rigidly connected to a portion of the vehicle, and the housmg 1 is rigidly ] 4 attached to a portion of the vehicle that rotates when the steering device Is turned to steer 15 the vehicle 16 To prevent fluid from leaking from the chamber 2 a sea] 36, preferably an Owing, 17 fits Into a groove 37 located between the indentations 13 and the knob 14, another seal 36, 18 preferably an Oring, fits into a channel 44 adjacent to an aperture 38 In the housing I 19 through which the bottom 39 of the shaft 12 extends. A keeper ring groove 40 near the 20 bottom 39 of the shaft 12 holds the shaft 12 in the housing 1. Also, a seal 36 is located in 21 a channel 41 in the housing I so that such seal 36 is between the housing 1 and the 22 faceplate 8 Finally, seals 36 are located in the depression 27 that fits around the cyhnducal 23 portion 29 of the wiper 7, in a channel 42 of the housing 1 around the aperture 32 through 24 which the bottom 30 of the cylindrical portion 31 of the wiper 7 extends, and around the 25 cylindrical portion 31 near bottom 30 and outside but near the housing 1.

26 The fluid may be Inserted through apertures 43 in the faceplate 8.

A second embodiment of the invention is shown in figures 10 and 11 It Is identical to that of figures I to 9 except that the discrete indentations 13 in the shah 12 are I replaced by a continuous indentation or groove 47 extending around the greater part ofthe circumference of the shaft, here rather more than 250 In the remaining sector of the circumference 45 there is no groove; then the groove is cut increasingly deeper into the shaft 12 as it progresses around the shaft. When it reaches the sector 45 the groove ends so that a wall exists between the deepest part 46 of the groove 47 and the sector 45. The control shaft 12, therefore, completely blocks the bypass channel 9 when the sector 45 has been rotated into the bypass channel 9, whereas it leaves the bypass channel 9 completely open when the deepest part 46 of the groove 47 has been rotated into the bypass channel 9 Selection of angular positions of the shaft 12 between these extremes permits continuous variation of the percentage of opening of the bypass channel 9. Damping is of course maximized when the bypass channel 9 is completely closed and minimized when the bypass channel 9 is completely opened. Thus, continuous (rather than discrete) adjustment of the damping will be possible by rotating the knob 14 and, consequently, the shaft 12.

In this second embodiment, one detent 17 and associated spring-loaded ball is provided as in the first embodiment above the sector 45 and one immediately above the deepest part 46 of the indentation 47.

Preferably the depth of the groove increases linearly with angle around the shah ie. the base of the groove follows a spiral form. Conveniently the groove is of constant width, and thus its cross-sectional area increase linearly with angle around the shaft.

Each feature disclosed in this specification (which term includes the claims) and/or

shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

Statements in this specification ofthe "objects ofthe invention" relate to preferred

embodiments of the invention, but not necessarily to all embodiments of the invention falling within the claims.

The description of the invention with reference to the drawings is by way of

example only.

The text of the abstract filed herewith is repeated here as part of the specification.

A fluidic damping device having a housing containing a rotatably mounted wiper that smilingly moves past the side walls, bottom, and peripheral wall of the housing as well as a faceplate attached to the top of the housing. The housing contains a bypass channel that has a first port in the first side wall of the chamber and a second port In the second side wall of the chamber. A control shaft is rotatably mounted within the housing. The control shaft has indentations of varying sizes formed at distinct points around the shaft with areas having no indentation between each consecutive pair of indentations and Is so located in the housing that either no indentation or only one indentation lies within the bypass channel at a given time. When no indentation has been rotated into the bypass channel, the control shaft completely blocks the bypass channel. Optionally, channels exist in the bottom of the faceplate or in the portion of the housing which forms the bottom of the chamber. These channels create areas where no damping occurs.

In an alternative embodiment a continuous groove of increasing crosssectional area replaces the discrete indentations, and extends around a major part (but not all) of the circumference of the shaft.

(Figure I)

Claims

( CLAIMS

I A fluids damping device comprising a chamber in which a wiper is rotatably mounted for movement in said chamber in sealing contact with walls of said chamber, a bypass conduit communicating with portions of said chamber on opposite sides of the wiper, and a rotary control valve disposed in said conduit, the angular position of the control valve controlling the extent to which the bypass conduit is occluded.
2 A damping device as claimed in claim 1 wherein the control valve comprises a shaft having a plurality of fluid pathways angularly spaced around the shalt to effect said controllable occlusion.
3. A damping device as claimed in ciamn 2 wherein the fluid pathways are of different sizes to each other, and are disposed so that only one pathway at a time communicates with the bypass conduit.
4. A damping device as claimed in claim 2 or claim 3 wherein the pathways are formed by indentations in the surface of the shaft.
5. A damping device as claimed in claim 1 wherein the control valve comprises a shaR having a groove of increasing cross-sectional area to effect said controllable occlusion.
6 A damping device as claimed in claim 5 wherein the groove extends around a major portion of the circumference of the shaft.
1 A damping device wherein the cross-sectional area ofthe groove increases linearly with angle around the shaft.
8. A damping device as claimed in any preceding claim comprising at least one local recess in a wall of the chamber to permit fluid to pass around the wiper at a predetermined angular position thereof relative to the chamber.

(). A fluidic damping device, which comprises: a housing having a generally sector-shaped chamber with a first side wall, a second side wall, a peripheral wall, and a bottom, said housing also containing a bypass channel having a first port in the first side wall and a second port in the second side wall, a control shaft, said control shaft having indentations of varying sizes formed at distinct points around the shah with areas having no indentation between each consecutive pair of indentations, the shaft being rotatably mounted in said housing so that either no indentation or a selectable one of said indentations can be positioned within the bypass channel at a given time; a faceplate sealingly mounted to the top of said housing; and a wiper rotatably mounted within said housing and having dimensions such that said wiper sealingly moves past side faceplate, said housing at the bottom of the chamber, al d the peripheral wall.

10 A fluidic damping device, which comprises: a housing having a generally sector-shaped chamber with a first side wall, a second side wall, a peripheral wall, "d a bottom, said housing also containing a bypass channel having afrst port in the first side wall and a second port in the second side wall; a control shaft, said control shad having a continuous indentation cut around said shaft in such a manner that in a sector there is no indentation in said shaft and then the indentation commences and becomes increasingly deeper as it progresses around said shR until the continuous indentation stops upon reaching the said sector, said shaft being rotatably mounted in said housing so that either the said sector or the indentation can be positioned within the bypass channel; a faceplate sealingly mounted to the top of said housing, and a wiper rotatably mounted within said housing and having dimensions such that said wiper sealingly moves past said faceplate, said housing at the bottom of the chamber, and the peripheral wall.

I I A damping device substantially as herein described with reference to and/or as shown In the accompanying drawings 12 A damping device as claimed in any preceding claim configured for use as a steenug damper.