CA1147664A - Power steering gear mechanism with rotary control valve - Google Patents
Power steering gear mechanism with rotary control valveInfo
- Publication number
- CA1147664A CA1147664A CA000355435A CA355435A CA1147664A CA 1147664 A CA1147664 A CA 1147664A CA 000355435 A CA000355435 A CA 000355435A CA 355435 A CA355435 A CA 355435A CA 1147664 A CA1147664 A CA 1147664A
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- valve
- pressure
- driven member
- pinion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/08—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by type of steering valve used
- B62D5/083—Rotary valves
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Power Steering Mechanism (AREA)
- Mechanically-Actuated Valves (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A power steering gear mechanism comprising a pinion adapted to be connected drivably to the steering, gear linkage for a road vehicle, a pressure cylinder, a double acting piston movable in said cylinder and defin-ing therewith a pair of pressure chambers, said piston being connected to or having formed thereon a gear rack that engages said pinion, a rotary valve mechanism hav-ing an internal rotatable valve element connected to a power input shaft, a valve sleeve adapted to be connected and to be rotatable with a said pinion, said fluid port-ing in said sleeve for distributing working pressure to either pressure chamber as a result of rotary displacement of said valve element with respect to said valve sleeve, the porting being arranged such that high pressure fluid in the porting establishes on said sleeve a force that urges said sleeve toward said pinion, the low pressure outlet port on said sleeve being situated at the end of said valve sleeve adjacent said pinion.
A power steering gear mechanism comprising a pinion adapted to be connected drivably to the steering, gear linkage for a road vehicle, a pressure cylinder, a double acting piston movable in said cylinder and defin-ing therewith a pair of pressure chambers, said piston being connected to or having formed thereon a gear rack that engages said pinion, a rotary valve mechanism hav-ing an internal rotatable valve element connected to a power input shaft, a valve sleeve adapted to be connected and to be rotatable with a said pinion, said fluid port-ing in said sleeve for distributing working pressure to either pressure chamber as a result of rotary displacement of said valve element with respect to said valve sleeve, the porting being arranged such that high pressure fluid in the porting establishes on said sleeve a force that urges said sleeve toward said pinion, the low pressure outlet port on said sleeve being situated at the end of said valve sleeve adjacent said pinion.
Description
POWER STEERING OEAR MECHANISM WITH ROTARY
CONTROL VALVE
The present inventlon relates generally to power steering gear mechanisms for use with automotive vehicles.
It comprises a pressure movable member defining a piston that is located in a pressure cylinder. The piston and the cylinder cooperate to define two working pressure cham-bers, one on each side of the piston. The piston is pro-vided with rack teeth that engage a pinion that in`turn is connected operatively to the steering gear linkage for the dirigible wheels of the vehicle.
A driver controlled torque input member is journalled in the cylinder housing and is situated in coaxial alignment with the piston. It is connected to a driven member of the steering gear mechanism by a torsion bar so that the input member may deflect angularly with respect to the driven member. The driven member in turn is connected to the pinion so that steering torque applied to the input shaft will be translated into a driving motion of the piston and the rack teeth in either one direction or the other depending upon the direction that torque is applied to the input shaft.
A pressure source, such as an engine driven power steering pump, not disclosed, distributes working pressure to the pressure chambers. Pressure distribution to the chambers is controlled by a rotary valve that comprises a first valve element connected to or formed in-tegrally with a torque input shaft. This valve element is rotatably disposed in a valve sleeve located within a valve housing at one end of the cylinder housing. The valve sleeve is ported so that fluid pressure may be admitted to a central region of the registering valve lands of the valve element and the sleeve. On either side of the inlet port is a high pressure distribution port extending to either pressure chamber. Fluid is circulated continuously through the valve system, and the outlet for .the circulating fluid is an outlet port located at the end of the valve spool adjacent the pinion.
',.,'~:~; ' The invention comprises improvements in a steering gear valve mechanism of the type that is disclosed in U.S.
Patents Nos. 3r680,~as3; 3,807,456 and 4,063,490 that are assigned to Ford Motor Company. The valve structure shown in U.S. Patent No. 4,063,490 includes a valve sleeve within which is situated a rotary valve element. The sleeve is provided with porting that establishes communication between the high pressure inlet port and each of two pressure dis-tribution chambers in a power steering gear. The outlet port is located at the rearward end of the valve structure.
The valve sleeve is pinned -to the driven member and axial thrust forces are transmitted from the driven member to the case through thrust bearings.
According to the present invention, a pin connection is provided between the torsion bar and the output member, and the pin of that pin connection is used also to establish a driving connection between the output member and the valve spool. The pin thus serves a double purpose and the axial length of the valve assembly is reduced because the need for providing two pin connections is eliminated. This improved construction also makes it possible to establish the pin connection at a location that is rela:tively remote from the bearing point for the output shaft so that the bearing length can be surface hardened. If the hole for the pin connection between the output member and the torsion bar were to be located relatively close to the bearing point of the output member as in certain prior art designs, drilling of the hole for the pin connection would be difficult from a manufacturing standpoint.
The registering valve portions for the sleeve and the valve element are relatively displaceable, one with respect to the other, upon deflection of the -torsion that connects the torque input member with the driven member.
The deflection of the torsion bar is proportional to the torque applied to the steering gear which, of course, is directly proportional to the steering effort applied -to the pinion. The magnitude of the displacement of the torsion bar, of course, determines the relative displacement of the valve portions of the sleeve of the valve element.
: - .
As torque is applied in one direction, the degree of commun-ication between the inlet port and the right turn port extending to one pressure chamber is increased as correspon~
ding pressure distribution from the inlet port to the left turn port extending to the opposite pressure chamber is decreased. The thrust due to pressure forces acting on the valve sleeve is in the direction of the pinion. No thrust washer is required to accommodate transfer of thrust forces from the sleeve to -the housing as in conventional arrangements. A pin and slot connection is provided between the driven member and the sleeve so tha-t the driven sleeve rotates with the driven member with a free floating relative-ly frictionless movement.
The invention is described further, by way of illustration, with reference to the accompanying drawings, wherein:
Figure l is an assembly view of a steering gear mechanism that includes a ro-tary pressure distribution valve;
Figure 2 is a cross-sectional view of the rotary pressure distribution valve for the steering gear of Figure l as seen from the plane of section line II-II of Figure 1 ;
Figure 3 is an enlarged view of a portion of the rotary valve mechanism of Figure 2;
Figure 4 is a cross-sectional end view of the valve of Figure 3 as seen from the plane of section line 4-4 of Figure 3;
Figure 5 is a plan view of the valve s-tructure of Figure 4 as seen from the plane of section line 5-5 of Figure 4;
Figure 6 is a cross-sectional view of an alter-nate rotary valve design for the steering gear of Figure 1 and provided in accordance with this invention; and Figure 6A is a cross-sectional view of the valve mechanism of Figure 6 as seen from the plane of section line 6A-6A of Figure 6.
r In Figure 1, reference numeral 10 generally des-ignates a cast housing. It includes a portion 12 that encloses a rack pinion 14 and a portion 16 that encloses a valve assembly 18. The pinion 14 engages drivably a rack 20 which extends transversel~ with respect to the axis of the pinion 14 and is suitabl~ journalled. Reference may be made to U.S. Patent No. 4,063,490 for a descrip-tion of one method for enclosing and supporting a rack such as the rack 20.
Pinion 14 is journalled at the lef-t-hand end, as seen in Figure 1, by bearing 22 which is capable of accommodating axial thrust~in either axial direction. The right-hand end of the pinion, as seen in ~igure 1, is jour-nalled by bushing 24. Closure member 26 enclosing the left-hand end of the opening in the housing 10 in which the pinion 14 is journalled.
The rack 20 is adapted -to be connec-ted to the steering linkage of the clirigible wheels oE a road vehicle.
It is urged into meshing engagement wi-th a pinion 14 by ~j . . ,; ~ ,, 7~
yoke 28 slidably positioned in a yoke cavity 30 formed in the housing portion 12. The yoke 28 is urged into slid-ing engagement with the rack 20 by means of compression spring 32.
The valve structure 18 includes a sleeve 34 which is provided with a first high pressure port 36 and a second high pressure port 38 which communicate respect-ively with the left turn pressure chamber and the right turn pressure chamber for the power booster cylinder.
10 Reference may be made to patent No. 4,063,490 for a show-ing of a power cylinder and piston mechanism capable of being used with the structure of Figure 1. The rack 20 is connected to and is formed integrally with the piston in a steering mechanism so that when pressure is distributed in the power cylinder to one side of the piston the rac~
20 is urged in one direction. It is urged in the opposite direction if the pressure build up occurs on the opposike side of the piston. In this way hydraulic power assist is achieved. This supplements the steering effort applied to the rack through the pinion 14.
A torque input shaft 40 is received within the sleeve 34. The shaft 40 is hollow and i~ receives there-through a torsion bar 42 which is pinned by means of a pin and slot connection 44 to the outboard end of the shaft 40.
The inboard end of the torsion rod 42 is pinned by a pin-and-slot connection to the output member of which the pinion 14 forms a part. The output member is provided With an opening 48 through which the pln 46 is received.
The sleeve 34 is positioned in a cylindrical opening 50 formed in the housing portion 16. A fluld seal 52 is situated on the output member and against a shoulder formed in the housing portion 16.
A high pressure fluid inlet port 54 formed in the sleeve 16 extends radially inward toward valve land 56 formed on the input shaft 40. The base of the valve land 7~
.
56 communicates with a central bore 58 in ~he input shaft 40 through a radial passage 60.
! The bore 58 communicates through passage 62, as seen in Figure ~, with space 64 between the input shaft 40 and the left-hand end of the sleeve 34. The slee~e 34 is ported at 66 so that it communicates with outlet passage 68 formed in ~he housing 16.
Ports 36 and 38 communicate respectively with left turn pressure passage 70 and right turn pressure passage 72, respectively.. These pressure passages extend to opposite sides of the piston for the fluid motor of which the power cylinder forms a part.
The pinion 14, which also may be referrecl to as a driven member, is provided with a radial opening 74 in which is positioned drive pin 76. The radially outward end of the pin 76 is received in slot 78 formed in the left-hand end of the sleeve 34 so that the rotary motion of the pinion 14 will be followed by correspondiny rotary motion of the sleeve 34.
The left-hand end of the input shaft 40 is piloted at 80 in a central cylindrical opening formed in the right-hand end of the pinion 14. The internal passage 58 in the input member 40 communicates through radial port 82 at the right hand side of the sleeve 34 so that the high pressure fluid in the inlet port 54 is transmitted directly to the right-hand end of the sleeve 34.
Fluid seal 84 is situated between the input shaft 40 and the right-hand end of the housing 16. It is held in place by snap riny 86. A spacer 88 is located between the sleeve 34 and the seal 84.
The sleeve 34 is provided with ring seals on either side of the port 36, on either side of the input port 54 and on either side of the right turn port 38.
Figure 3 shows an enlargement oE the valve land 54. The land is defined by a cavity ~0 which comprises ,. ...... ~, ............ . ; . , . . . . , . ~
.
g a milled slot in the input shaft 40. The slots are angularly disposed about the axis of the shat 40.
The corner of the slots 90 are chamfered as seen in Fi~ure 4 at 92. The chamfer is defined by a S crescent surface as in~icated in the plan view of Figure 5. The geometry of the chamfer and the geometry of the slots 90 are controlled so that sufficient valve clearance is provided to accommodate the 1OW of fluid through the valve mechanism and for the distribution of pressure to each of the pressure ports 36 and 38. A typical valve opening between the internal valve land 94 formed in the sleeve 34 and the slot 90 is shown in Figureo4. The valve lands 94 are in the form of axial flats situated in angularly disposed relationship about the axis of the sleeve 34 and these lands register with the lands 54 formed on the member 40.
When torque is applied to the torque input shaft 40 in one direction, torsion bar 42 yields thereby decreasing the opening between the lands 94 and 54 that communicate with one passage while the degree oE communi-cation through the lands with the other pressure passages is increased. This effects a turn in either a right dlrection or a left direction depending upon the direction of the torque applied to the shaft 40.
A valve mechanism provides a continuously open ~lui~ circuit between the inlet port 54 and the outlet port 68 as previously described. The pressure that acts on the right-hand end of the valve sleeve 34 exceecls the pressure forces acting in a right-hand direction on the valve sleeve. Thus the valve sleeve is forced normally toward pinion 14. There is no necessity, therefore~ to provide a thrust washer at the right-hand end of the valve sleeve.
The power assist provided by the power cylinder and piston assembly is in a direction that supplements the steering effort applied to the input shaft 40. The ... . . ..
input shaEt 40 is situated as shown in Figure 2 within the right-hand end of the pinion or driven member 14 to define a lost motion connection, which is identified by reference charac-ter g6. If -the torsion rod 42 deflects beyond a 5 certain angular e2~tent, the lost motion connection at 96 will establish a direct driving relationship between the shaft 40 and the pinion 14.
In Figure 6, there is shown an alterna-te valve construction that employs a single drive pin for connecting 10 both the torsion rod and the valve sleeve to the driven member or pinion 14, in accordance with the present invention. The drive pin that serves this dual purpose is identified in Figure 6 by reference numeral 100. The pins in the Figure 2 construction that the drive pin 100 15 replaces are shown at 46 and 76. The pinion 14', which forms a counterpart for the pinion 14 of the Figure 2 con-struction, is provided with an opening 102 through which the pin 100 is received. The radially outward end of the pin 100 is received in opening 104 in the left hand end 20 of the valve sleeve 34', which forms a counterpart for the sleeve of Figure 2. Thus the sleeve 34' and the pinion 14 move in unison although there is no net hydraulic force acting on -the sleeve 34 in a right-hand direction. Because of the fact that pressure is dis-25 tributed to the right-hand end of the sleeve as in the Figure 2 construction, the pin connection be-tween the sleeve 34' and the pinion 14' may be a loose fitting connection; and it functions in a fashion similar to the pin and slot connection shown at 76 and 78 in 30 Figure 2.
The other elements of the valve structure shown in Figure 6 have counterpart elements in the Figure 2 structure, and for this reason corresponding elements of each figure are shown by the same reference numerals although 35 prime notations have been added to the Figure 6 construc-tion. The lost motion connection between the driving shaft 40 and the pinion 14 is shown in Figure 6A.
.il ,~1 ,'~ r~tf `~` q ~ 11 ~
This connection is similar to the one described in Figure 2A. For this reason similar numerals have been used to ~esignate the common elements although prime notations have been added to the Figure 6A construction.
, . .
.
... . . . ,_. _ . ... _ ... .. ~ .... . . . ... ,; . . , .. . . _ _
CONTROL VALVE
The present inventlon relates generally to power steering gear mechanisms for use with automotive vehicles.
It comprises a pressure movable member defining a piston that is located in a pressure cylinder. The piston and the cylinder cooperate to define two working pressure cham-bers, one on each side of the piston. The piston is pro-vided with rack teeth that engage a pinion that in`turn is connected operatively to the steering gear linkage for the dirigible wheels of the vehicle.
A driver controlled torque input member is journalled in the cylinder housing and is situated in coaxial alignment with the piston. It is connected to a driven member of the steering gear mechanism by a torsion bar so that the input member may deflect angularly with respect to the driven member. The driven member in turn is connected to the pinion so that steering torque applied to the input shaft will be translated into a driving motion of the piston and the rack teeth in either one direction or the other depending upon the direction that torque is applied to the input shaft.
A pressure source, such as an engine driven power steering pump, not disclosed, distributes working pressure to the pressure chambers. Pressure distribution to the chambers is controlled by a rotary valve that comprises a first valve element connected to or formed in-tegrally with a torque input shaft. This valve element is rotatably disposed in a valve sleeve located within a valve housing at one end of the cylinder housing. The valve sleeve is ported so that fluid pressure may be admitted to a central region of the registering valve lands of the valve element and the sleeve. On either side of the inlet port is a high pressure distribution port extending to either pressure chamber. Fluid is circulated continuously through the valve system, and the outlet for .the circulating fluid is an outlet port located at the end of the valve spool adjacent the pinion.
',.,'~:~; ' The invention comprises improvements in a steering gear valve mechanism of the type that is disclosed in U.S.
Patents Nos. 3r680,~as3; 3,807,456 and 4,063,490 that are assigned to Ford Motor Company. The valve structure shown in U.S. Patent No. 4,063,490 includes a valve sleeve within which is situated a rotary valve element. The sleeve is provided with porting that establishes communication between the high pressure inlet port and each of two pressure dis-tribution chambers in a power steering gear. The outlet port is located at the rearward end of the valve structure.
The valve sleeve is pinned -to the driven member and axial thrust forces are transmitted from the driven member to the case through thrust bearings.
According to the present invention, a pin connection is provided between the torsion bar and the output member, and the pin of that pin connection is used also to establish a driving connection between the output member and the valve spool. The pin thus serves a double purpose and the axial length of the valve assembly is reduced because the need for providing two pin connections is eliminated. This improved construction also makes it possible to establish the pin connection at a location that is rela:tively remote from the bearing point for the output shaft so that the bearing length can be surface hardened. If the hole for the pin connection between the output member and the torsion bar were to be located relatively close to the bearing point of the output member as in certain prior art designs, drilling of the hole for the pin connection would be difficult from a manufacturing standpoint.
The registering valve portions for the sleeve and the valve element are relatively displaceable, one with respect to the other, upon deflection of the -torsion that connects the torque input member with the driven member.
The deflection of the torsion bar is proportional to the torque applied to the steering gear which, of course, is directly proportional to the steering effort applied -to the pinion. The magnitude of the displacement of the torsion bar, of course, determines the relative displacement of the valve portions of the sleeve of the valve element.
: - .
As torque is applied in one direction, the degree of commun-ication between the inlet port and the right turn port extending to one pressure chamber is increased as correspon~
ding pressure distribution from the inlet port to the left turn port extending to the opposite pressure chamber is decreased. The thrust due to pressure forces acting on the valve sleeve is in the direction of the pinion. No thrust washer is required to accommodate transfer of thrust forces from the sleeve to -the housing as in conventional arrangements. A pin and slot connection is provided between the driven member and the sleeve so tha-t the driven sleeve rotates with the driven member with a free floating relative-ly frictionless movement.
The invention is described further, by way of illustration, with reference to the accompanying drawings, wherein:
Figure l is an assembly view of a steering gear mechanism that includes a ro-tary pressure distribution valve;
Figure 2 is a cross-sectional view of the rotary pressure distribution valve for the steering gear of Figure l as seen from the plane of section line II-II of Figure 1 ;
Figure 3 is an enlarged view of a portion of the rotary valve mechanism of Figure 2;
Figure 4 is a cross-sectional end view of the valve of Figure 3 as seen from the plane of section line 4-4 of Figure 3;
Figure 5 is a plan view of the valve s-tructure of Figure 4 as seen from the plane of section line 5-5 of Figure 4;
Figure 6 is a cross-sectional view of an alter-nate rotary valve design for the steering gear of Figure 1 and provided in accordance with this invention; and Figure 6A is a cross-sectional view of the valve mechanism of Figure 6 as seen from the plane of section line 6A-6A of Figure 6.
r In Figure 1, reference numeral 10 generally des-ignates a cast housing. It includes a portion 12 that encloses a rack pinion 14 and a portion 16 that encloses a valve assembly 18. The pinion 14 engages drivably a rack 20 which extends transversel~ with respect to the axis of the pinion 14 and is suitabl~ journalled. Reference may be made to U.S. Patent No. 4,063,490 for a descrip-tion of one method for enclosing and supporting a rack such as the rack 20.
Pinion 14 is journalled at the lef-t-hand end, as seen in Figure 1, by bearing 22 which is capable of accommodating axial thrust~in either axial direction. The right-hand end of the pinion, as seen in ~igure 1, is jour-nalled by bushing 24. Closure member 26 enclosing the left-hand end of the opening in the housing 10 in which the pinion 14 is journalled.
The rack 20 is adapted -to be connec-ted to the steering linkage of the clirigible wheels oE a road vehicle.
It is urged into meshing engagement wi-th a pinion 14 by ~j . . ,; ~ ,, 7~
yoke 28 slidably positioned in a yoke cavity 30 formed in the housing portion 12. The yoke 28 is urged into slid-ing engagement with the rack 20 by means of compression spring 32.
The valve structure 18 includes a sleeve 34 which is provided with a first high pressure port 36 and a second high pressure port 38 which communicate respect-ively with the left turn pressure chamber and the right turn pressure chamber for the power booster cylinder.
10 Reference may be made to patent No. 4,063,490 for a show-ing of a power cylinder and piston mechanism capable of being used with the structure of Figure 1. The rack 20 is connected to and is formed integrally with the piston in a steering mechanism so that when pressure is distributed in the power cylinder to one side of the piston the rac~
20 is urged in one direction. It is urged in the opposite direction if the pressure build up occurs on the opposike side of the piston. In this way hydraulic power assist is achieved. This supplements the steering effort applied to the rack through the pinion 14.
A torque input shaft 40 is received within the sleeve 34. The shaft 40 is hollow and i~ receives there-through a torsion bar 42 which is pinned by means of a pin and slot connection 44 to the outboard end of the shaft 40.
The inboard end of the torsion rod 42 is pinned by a pin-and-slot connection to the output member of which the pinion 14 forms a part. The output member is provided With an opening 48 through which the pln 46 is received.
The sleeve 34 is positioned in a cylindrical opening 50 formed in the housing portion 16. A fluld seal 52 is situated on the output member and against a shoulder formed in the housing portion 16.
A high pressure fluid inlet port 54 formed in the sleeve 16 extends radially inward toward valve land 56 formed on the input shaft 40. The base of the valve land 7~
.
56 communicates with a central bore 58 in ~he input shaft 40 through a radial passage 60.
! The bore 58 communicates through passage 62, as seen in Figure ~, with space 64 between the input shaft 40 and the left-hand end of the sleeve 34. The slee~e 34 is ported at 66 so that it communicates with outlet passage 68 formed in ~he housing 16.
Ports 36 and 38 communicate respectively with left turn pressure passage 70 and right turn pressure passage 72, respectively.. These pressure passages extend to opposite sides of the piston for the fluid motor of which the power cylinder forms a part.
The pinion 14, which also may be referrecl to as a driven member, is provided with a radial opening 74 in which is positioned drive pin 76. The radially outward end of the pin 76 is received in slot 78 formed in the left-hand end of the sleeve 34 so that the rotary motion of the pinion 14 will be followed by correspondiny rotary motion of the sleeve 34.
The left-hand end of the input shaft 40 is piloted at 80 in a central cylindrical opening formed in the right-hand end of the pinion 14. The internal passage 58 in the input member 40 communicates through radial port 82 at the right hand side of the sleeve 34 so that the high pressure fluid in the inlet port 54 is transmitted directly to the right-hand end of the sleeve 34.
Fluid seal 84 is situated between the input shaft 40 and the right-hand end of the housing 16. It is held in place by snap riny 86. A spacer 88 is located between the sleeve 34 and the seal 84.
The sleeve 34 is provided with ring seals on either side of the port 36, on either side of the input port 54 and on either side of the right turn port 38.
Figure 3 shows an enlargement oE the valve land 54. The land is defined by a cavity ~0 which comprises ,. ...... ~, ............ . ; . , . . . . , . ~
.
g a milled slot in the input shaft 40. The slots are angularly disposed about the axis of the shat 40.
The corner of the slots 90 are chamfered as seen in Fi~ure 4 at 92. The chamfer is defined by a S crescent surface as in~icated in the plan view of Figure 5. The geometry of the chamfer and the geometry of the slots 90 are controlled so that sufficient valve clearance is provided to accommodate the 1OW of fluid through the valve mechanism and for the distribution of pressure to each of the pressure ports 36 and 38. A typical valve opening between the internal valve land 94 formed in the sleeve 34 and the slot 90 is shown in Figureo4. The valve lands 94 are in the form of axial flats situated in angularly disposed relationship about the axis of the sleeve 34 and these lands register with the lands 54 formed on the member 40.
When torque is applied to the torque input shaft 40 in one direction, torsion bar 42 yields thereby decreasing the opening between the lands 94 and 54 that communicate with one passage while the degree oE communi-cation through the lands with the other pressure passages is increased. This effects a turn in either a right dlrection or a left direction depending upon the direction of the torque applied to the shaft 40.
A valve mechanism provides a continuously open ~lui~ circuit between the inlet port 54 and the outlet port 68 as previously described. The pressure that acts on the right-hand end of the valve sleeve 34 exceecls the pressure forces acting in a right-hand direction on the valve sleeve. Thus the valve sleeve is forced normally toward pinion 14. There is no necessity, therefore~ to provide a thrust washer at the right-hand end of the valve sleeve.
The power assist provided by the power cylinder and piston assembly is in a direction that supplements the steering effort applied to the input shaft 40. The ... . . ..
input shaEt 40 is situated as shown in Figure 2 within the right-hand end of the pinion or driven member 14 to define a lost motion connection, which is identified by reference charac-ter g6. If -the torsion rod 42 deflects beyond a 5 certain angular e2~tent, the lost motion connection at 96 will establish a direct driving relationship between the shaft 40 and the pinion 14.
In Figure 6, there is shown an alterna-te valve construction that employs a single drive pin for connecting 10 both the torsion rod and the valve sleeve to the driven member or pinion 14, in accordance with the present invention. The drive pin that serves this dual purpose is identified in Figure 6 by reference numeral 100. The pins in the Figure 2 construction that the drive pin 100 15 replaces are shown at 46 and 76. The pinion 14', which forms a counterpart for the pinion 14 of the Figure 2 con-struction, is provided with an opening 102 through which the pin 100 is received. The radially outward end of the pin 100 is received in opening 104 in the left hand end 20 of the valve sleeve 34', which forms a counterpart for the sleeve of Figure 2. Thus the sleeve 34' and the pinion 14 move in unison although there is no net hydraulic force acting on -the sleeve 34 in a right-hand direction. Because of the fact that pressure is dis-25 tributed to the right-hand end of the sleeve as in the Figure 2 construction, the pin connection be-tween the sleeve 34' and the pinion 14' may be a loose fitting connection; and it functions in a fashion similar to the pin and slot connection shown at 76 and 78 in 30 Figure 2.
The other elements of the valve structure shown in Figure 6 have counterpart elements in the Figure 2 structure, and for this reason corresponding elements of each figure are shown by the same reference numerals although 35 prime notations have been added to the Figure 6 construc-tion. The lost motion connection between the driving shaft 40 and the pinion 14 is shown in Figure 6A.
.il ,~1 ,'~ r~tf `~` q ~ 11 ~
This connection is similar to the one described in Figure 2A. For this reason similar numerals have been used to ~esignate the common elements although prime notations have been added to the Figure 6A construction.
, . .
.
... . . . ,_. _ . ... _ ... .. ~ .... . . . ... ,; . . , .. . . _ _
Claims
1. In a power steering system having a fluid motor with a pressure movable member, a driven member connected operatively to said pressure movable member through a gearing mechanism and a torque input member coaxially disposed with respect to said driven member, the improvement comprising:
a valve mechanism comprising a valve sleeve situ-ated over said torque input member, a torsion bar connection between said input member and said driven member;
a mechanical connection between said driven member and said sleeve, a first rotary valve element having external valve lands carried by said input member, internal rotary valve lands formed in said sleeve, said internal and external valve lands registering one with respect to the other, first and second pressure ports ion said valve sleeve communicating respectively with opposite sides of said pressure movable member of said motor, a high pressure inlet port in said sleeve commun-icating with said valve lands, said valve lands being adapted to distribute fluid pressure selectively from said inlet port to each of said pressure passages as said input shaft is moved relative to said driven member, a central passage formed in said input member, an outlet port located between said valve spool and said driven member, said outlet port and said inlet port commun-icating with the interior of said driving member, the end of said sleeve remote from said driven member being in communication with the interior of said driving member, the net effective pressure force acting on said sleeve being directed toward said driven member, and a pin connection between said torsion rod and said driven member, the pin connection between said driven member and said sleeve including a common pin extending radially through one end of said driven member and through one end of said torsion rod, the end of said sleeve adjacent said driven member having an opening formed therein for receiving the radially outward end of said pin.
a valve mechanism comprising a valve sleeve situ-ated over said torque input member, a torsion bar connection between said input member and said driven member;
a mechanical connection between said driven member and said sleeve, a first rotary valve element having external valve lands carried by said input member, internal rotary valve lands formed in said sleeve, said internal and external valve lands registering one with respect to the other, first and second pressure ports ion said valve sleeve communicating respectively with opposite sides of said pressure movable member of said motor, a high pressure inlet port in said sleeve commun-icating with said valve lands, said valve lands being adapted to distribute fluid pressure selectively from said inlet port to each of said pressure passages as said input shaft is moved relative to said driven member, a central passage formed in said input member, an outlet port located between said valve spool and said driven member, said outlet port and said inlet port commun-icating with the interior of said driving member, the end of said sleeve remote from said driven member being in communication with the interior of said driving member, the net effective pressure force acting on said sleeve being directed toward said driven member, and a pin connection between said torsion rod and said driven member, the pin connection between said driven member and said sleeve including a common pin extending radially through one end of said driven member and through one end of said torsion rod, the end of said sleeve adjacent said driven member having an opening formed therein for receiving the radially outward end of said pin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US6208679A | 1979-07-30 | 1979-07-30 | |
| US62,086 | 1979-07-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1147664A true CA1147664A (en) | 1983-06-07 |
Family
ID=22040128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000355435A Expired CA1147664A (en) | 1979-07-30 | 1980-07-04 | Power steering gear mechanism with rotary control valve |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5625056A (en) |
| CA (1) | CA1147664A (en) |
| DE (1) | DE3023321A1 (en) |
| GB (1) | GB2055717B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2122152B (en) * | 1982-06-18 | 1986-06-25 | Cam Gears Ltd | A power assisted steering gear |
| GB2162477B (en) * | 1984-08-01 | 1988-01-20 | Trw Cam Gears Ltd | Valve assembly for a power assisted steering gear |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB834761A (en) * | 1957-10-02 | 1960-05-11 | Gen Motors Corp | Improved fluid pressure power steering mechanism for a motor vehicle |
| GB1465445A (en) * | 1974-09-13 | 1977-02-23 | Ford Motor Co | Rack and pinion power steering gear |
| FR2382361A1 (en) * | 1977-03-02 | 1978-09-29 | Dba | Hydraulically assisted pilot valve - is used with double acting cylinder and controlled by rotary composite shaft |
| DE2745786C2 (en) * | 1977-10-12 | 1982-03-04 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Pressure medium control device for power steering, in particular for motor vehicles |
-
1980
- 1980-06-21 DE DE19803023321 patent/DE3023321A1/en not_active Ceased
- 1980-07-04 CA CA000355435A patent/CA1147664A/en not_active Expired
- 1980-07-22 GB GB8023910A patent/GB2055717B/en not_active Expired
- 1980-07-29 JP JP10423180A patent/JPS5625056A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3023321A1 (en) | 1981-02-12 |
| GB2055717B (en) | 1984-02-08 |
| JPS5625056A (en) | 1981-03-10 |
| GB2055717A (en) | 1981-03-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4063490A (en) | Rack and pinion power steering gear mechanism | |
| US4570736A (en) | Dual flow variable assist power steering gear mechanism | |
| US4561521A (en) | Variable assist power steering system | |
| US4311171A (en) | Hydrostatic steering controller with pressure dams | |
| US4469342A (en) | Rotary valve for a power assisted steering mechanism | |
| US4516471A (en) | Power steering valve with chamfered lands | |
| US4577660A (en) | Rotary servovalve | |
| US3709099A (en) | Convertible rack and pinion steering gear | |
| EP0218982B1 (en) | Unloading valve for integral gear | |
| US4378030A (en) | Power steering gear mechanism with rotary control valve | |
| US4586581A (en) | Vehicle control system | |
| US5392875A (en) | Hydraulic reaction variable assist power steering system | |
| CA1147664A (en) | Power steering gear mechanism with rotary control valve | |
| US4371002A (en) | Hydrostatic steering system | |
| US3733967A (en) | Power steering mechanism for automotive vehicles | |
| GB2211802A (en) | A power steering gear system for a vehicle | |
| US5307895A (en) | Hydraulic reaction variable assist power steering control hydraulic "detent" | |
| US6035957A (en) | Power steering control valve balancing | |
| US4633963A (en) | Power steering apparatus | |
| KR930002434B1 (en) | Steering gear ratio changing apparatus | |
| GB2154188A (en) | Power steering assembly | |
| US4495769A (en) | Booster power steering | |
| US5711395A (en) | Rotary slide valve for power-assisted steering mechanisms of motor vehicles | |
| US4438679A (en) | Axial thrust compensating means for power steering control valve | |
| US4779646A (en) | Fluid flow control valve |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |