US3657967A - Power steering apparatus - Google Patents

Power steering apparatus Download PDF

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Publication number
US3657967A
US3657967A US858380A US3657967DA US3657967A US 3657967 A US3657967 A US 3657967A US 858380 A US858380 A US 858380A US 3657967D A US3657967D A US 3657967DA US 3657967 A US3657967 A US 3657967A
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United States
Prior art keywords
valve
pressure
flap
flap valves
pistons
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Expired - Lifetime
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US858380A
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English (en)
Inventor
Akira Suzuki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyoda Koki KK
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Toyoda Koki KK
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    • 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

Definitions

  • FIG. l2 IIIIIIII FIG. l2
  • the present invention relates to power steering apparatus, and more particularly to power steering apparatus comprising a hydraulic motor to boost the power applied by manual steering, said apparatus comprising servo valve means wherein flap valves are angularly moved by manual steering to control the pressure fluid for operating the hydraulic motor.
  • the flap valve mechanism is so sensitive that when a strong turning force acts on steerable wheels, the flap valves begin to vibrate and in consequence the stability of the valve may be impaired, an unpleasant noise may occur, and the steering operation may become unsatisfactory.
  • a very simple device attached to the flap valve mechanism can absorb the surge pressure generated in the hydraulic pressure circuit as well as effectively damp the vibration of the flap valves.
  • the present invention stabilizes the valve characteristics of the flap valve mechanism and enhances the steering performance.
  • the primary object of the present invention is to provide power steering apparatus comprising means for damping the vibration of flap valves.
  • Another object of the present invention is to provide power steering apparatus in which any surge pressure generated in the hydraulic pressure circuit is absorbed.
  • Still another object is to provide power steering apparatus which comprises a surge pressure absorbing device in the hydraulic pressure circuit which absorbs the surge pressure generated by a sudden action of the flap valves.
  • Yet another object is to provide power steering apparatus in which the vibration damping of flap valves and the absorption of surge pressure is attained by a simple mechanism.
  • FIG. 1 is a longitudinal section through a power steering apparatus constituting one embodiment of the present invention
  • FIG. 2 is a transverse sectional view of the apparatus taken along the line IIII of FIG. 1;
  • FIG. 3 is a sectional view of the apparatus taken along the line III-III of FIG. 2;
  • FIG. 4 shows a partial enlargement of FIG. 1
  • FIG. 5, FIG. 6, FIG. 7 and FIG. 8 are sectional views of the apparatus taken along the lines V-V, Vl-VI, VII-VII, and VlII--VIII in FIG. 4, respectively;
  • FIG. 9 is a sectional view on an enlarged scale of the essential part of a power steering apparatus in another embodiment of the present invention.
  • FIG. 10 is a sectional view of the essential part of a power steering apparatus in still another embodiment of the present invention.
  • FIG. 11 is a sectional view showing part of the apparatus illustrated in FIG. 10 on an enlarged scale
  • FIG. 12 is a sectional view of the essential part of a power steering apparatus in a fourth embodiment of the present invention.
  • FIG. 13 is a sectional view of the essential part of a power steering apparatus in a fifth embodiment of the present invention.
  • reference numeral 11 indicates the main body of a power steering apparatus having a rotating shaft 12 rotatably supported therein.
  • One end of the rotating shaft 12 is connected via a pitman arm and a connecting rod (not shown) and other connecting means to the steerable wheels of a vehicle.
  • Two axially spaced partial gears 13 and 14 are mounted on the rotating shaft 12. These gears are concentric with the rotating shaft 12 and their teeth extend in opposite directions.
  • a hydraulic pressure cylinder 15 In the main body of the power steering apparatus is a hydraulic pressure cylinder 15.
  • a piston 16 (FIG. 3) is mounted in said cylinder for sliding movement in a direction at right angles to the axis of the rotating shaft 12.
  • a rack 18 At one end of the piston 16 is a rack 18, the bottom of which is supported by a bearing 17.
  • the rack 18 meshes with the gear 13 on the rotating shaft 12. As shown in FIG. 3, the end of the cylinder 15 is closed by a cylinder cover 19 and a ring 20.
  • a servo valve housing 21 is attached to the main body 11 of the power steering apparatus.
  • Reference numeral 22 indicates a steering shaft, one end of which is supported in the housing 21 and the other end of whichis supported in the main body 11.
  • the axis of the steering shaft 22 is parallel to the axis of the piston 16.
  • a nut 23 encircles ball bearings 24 which roll ina spiral groove in the steering shaft 22, and rotation of the shaft 22 shifts the nut member 23 in an axial direction against small frictional resistance.
  • the nut 23 is provided with a rack portion 23a, which meshes with the gear 14 on the rotating shaft 12.
  • the servo valve housing 21 is shown to be provided with a pressure fluid supply port 25 axially spaced from a discharge port 26.
  • the supplydischarge ports 27 and 28 which communicate through conduits 59 and 60 respectively with a left compartment 15a and a right compartment 15b of the hydraulic pressure cylinder 15.
  • a main valve member 29 is rotatably mounted within the housing 21, and one end of the main valve member 29 faces toward a coupling member 30.
  • Two axially spaced annular grooves 31 and 32 are cut into the periphery of the main valve member 29 and the supply-discharge ports 27 and 28 open into the grooves 31 and 32 respectively.
  • valve chambers 35 and 36 housing first flap valves 33 and second flap valves 34, which are rotatable with respect to the main valve member 29 (see FIGS. 5 and 6).
  • a valvemember 37 having radial projections which form the first flap valves 33 is so housed as to be able to swing around the axis of the chamber.
  • a steering shaft 38 having radial projections forming the second flap valves 34, is mounted to swing freely around the axis of the chamber.
  • the steering shaft 38 is aligned with the axis of the steering shaft 22 and is resiliently connected via a double torsion-bar 40 (to be described later) to the steering shaft 22.
  • the steering shaft 38 is supported in a sealed bearing member 39 fastened to one end of the servo valve housing 21, and the projecting right end of the steering shaft 38 is connected via couplings and the like (not shown) to a steering column and a steering wheel to be operated by the driver.
  • the steering shaft 38 with the projections forming the second flap valves 34, the valve member 37 with the projections forming the first flap valves 33, and the coupling member 30 engaging the steering shaft 22 are connected by pins to the double torsion-bar 40 which is coaxial with the steering shafts 38 and 22, which are resiliently coupled together by the double toision-bar 40.
  • the double torsion-bar 40 comprises resilient portion 40a having a relatively small diameter and a small spring constant, and a resilient portion 4011 having a larger diameter and a larger spring constant than that of the smaller diameter portion 400.
  • the valve chamber 35 which houses the first flap valves 33, as shown in FIG. 5, communicates with the supply. port 25,
  • the valve chamber 36 which houses the second flap valves 34, communicates with the discharge port 26 and has, as shown in FIG. 6, a pair of jet ports 36a and 36b on opposite sides of the second flap valves 34.
  • the gap formed between the valve seats 34a on the second flap valves 34 and the jet ports 36a and 36b is made slightly wider than that between the valve seats 33a on opposite sides of the first flap valves 33 and the distribution ports 35a and 35b.
  • Cylindrical holes 41 extend axially through the main valve member 29, as shown in FIG. 4, and terminate adjacent the inner sides of the first and second flap valves 33 and 34.
  • Cylindrical holes 41 extend axially through the main valve member 29, as shown in FIG. 4, and terminate adjacent the inner sides of the first and second flap valves 33 and 34.
  • Springs 45 and 46 are inserted while compressed in the spaces between the pressure-exerting pistons 42 and 43 and the free piston 44.
  • first flap valves 33 and the second flap valves 34 are subjected by the pistons 42 and 43 to pressures proportional to the pressures generated in the left compartment 15a and in the right compartment 15b of cylinder 15, and unstable vibration of first and second flap valves 33 and 34 can be eliminated by the frictional force between the pressure-exerting pistons 42 and 43 and the first and second flap valves 33 and 34, thus making the valve characteristics more stable.
  • the distribution ports 35a opening into the valve chamber 35 communicate through fluid conduits 49 with the annular concave groove 31, while the distribution ports 35b communicate through fluid conduits 50 with the annular concave groove 32.
  • the jet ports 36a opening into the valve chamber 36 communicate through fluid conduits 51 with the annular concave groove 32, while the jet ports 36b communicate through fluid conduits 52 with the annular concave groove 31.
  • the supply port 25 communicates through a supply pipe 53 with a pressure fluid supply pump 54, while the discharge port 26 communicates through a discharge pipe 55 with a fluid tank 56.
  • the supply pump 54 is driven by the driving means 57 such as an automobile engine, and the delivery pressure is kept at less than a predetermined value by means of a relief valve 58.
  • the supply pump 54 When, in the above arrangement, the supply pump 54 is started to supply a pressure fluid through the supply port 25 into the servo valve housing 21, the pressure fluid admitted into the valve chamber 35 passes through the distribution ports 35a and 35b (shown in FIG. 5), through the fluid conduits 49 and 50, through the annular grooves 31 and 32 to the supply exhaust ports 27 and 28 of the hydraulic pressure cylinder 15. Said fluid also passes through the fluid conduits 51 and 52 to the jet ports 36a and 36b. At the neutral positions of first flap valves 33 and second flap valves 34, both the distribution ports 35a and 35b and both the jet ports 36a and 36b are open, and accordingly the greater part of the fluid supplied passes through the jet ports 36a and 36b and discharge port 26 back to the fluid tank 56 to be reclaimed. Therefore, the pressures in the left compartment 15a and in the right compartment 15b, without rising, are balanced with each other and in consequence the piston 16 does not move.
  • the jet ports 36b are closed by the second flap valves 34 and the flow to the discharge port 26 is restricted. Accordingly, the pressure fluid passes through the annular concave groove 31, the port 27 and the conduit 59 to the left compartment 15a of the hydraulic pressure cylinder 15, thereby urging the piston 16 to the right in FIG. 3.
  • the fluid within the right hand compartment 15b of the cylinder 15 is discharged into the fluid tank 56 through the conduit 60, the port 28, the annular concave groove 32, the fluid conduits 51 and the wide-open jet ports 36a. In this manner, a slight steering torque applied by the driver to the steering wheel is boosted by the piston 16 to assist it in turning the rotating shaft 12, which turns the steerable wheels in right direction.
  • the pressure fluid supplied to the distribution ports 35a, passing through the fluid conduits 49 and the annular concave groove 31, is introduced through the narrow hole 47 into the cylinder holes 41 in the main valve member 29, thereby causing the pistons 42 to press against the first flap valves 33 and at the same time causing the free pistons 44 to displace, thereby compressing the springs 46 and urging the pistons 43 against the second flap valves 34.
  • the frictional force developed between the pistons 42 and 43 and the first and second flap valves 33 and 34 damps the instable vibration of the first and second flap valves 33 and 34 to ensure excellent stability. Therefore the driver does not feel the vibration and accordingly an improved steering performance as well as the elimination of unpleasant noise due to vibration results.
  • FIG. 9 illustrates another embodiment of the present invention which is essentially no different from the preceding embodiment except that, in the former, the vibrations of the first and second flap valves 33 and 34 and the surge pressure are effectively damped and absorbed by an additional throttle valve installed in the hydraulic pressure circuit.
  • Constrictions 61 and 62 are respectively provided in conduits 59 and 60 which connect the supply-exhaust ports 27 and 28 to. the right compartment 15a and the left compartment 15b of the hydraulic pressure cylinder 15. Otherwise, the arrangement is entirely the same as shown in FIG. 4, so identical symbols are used to indicate the identical parts and further description is omitted here.
  • the vibrations excited in the first and second flap valves 33 and 34 are mostly attributable to the steerable wheels. For instance, when the steerable wheels of a running car are forcibly deflected the mainvalve member 29 is forced to deflect in response to pressure exerted through the rotating shaft 12, the nut member 23 and the steering shaft 22.
  • FIG. illustrates still another embodiment of the present invention, in which there is no free piston 44 between the pressure-exerting pistons 42 and 43, and there is a surge pressure absorbing device inserted in the conduits 59 and 60.
  • a compressed spring 45 is inserted between two pressure-exerting pistons 42 and 43.
  • a narrow hole 63 is cut in the pressure-exerting piston 42 contactingthe first flap. valves 33, and a pressure fluid is admitted through the supply port 25 to the back side of the pressure-exerting pistons 42 and 43.
  • the first flap valves 33 and the second flap. valves 34 are respectively subjected to pressure from the push pistons 42 and 43, and because of the frictional force between the first flap valves 33 and the pressure-exerting pistons 42 and between the second flap valves 34 and the pressure-exerting pistons 43, unstable vibrations of the first and second flap valves 33 and 34 can be eliminated to stabilize their valve characteristics.
  • valve holes 64 and 65 are provided midway in the conduits 59 and 60, and in the valve holes 64 and 65 are slidably mounted spools 66, 67, 68 and 69, and between the spools 66 and 67 and the spools 68 and 69 compressed springs 70 and 71 are so positioned that the forces exerted by these springs nonnally keep the spools 66, 67, 68 and 69 in positions at both ends of 65 the valve holes 64 and 65.
  • the spools 66, 67, 68 and 69 are respectively equipped with conduits 72, 73, 74 and 75 provided with constrictions which act as throttles, and these conduits provide communication between the right and left compartments of the hydraulic cylinder 15 and the ports 27 and 28.
  • a space 76 is left between the spools 66 and 67 and a space 77 between the spools 68 and 69 and the spaces 76 and 77 are connected by a conduit 78.
  • an abnormal pressure i.e., a surge pressure develops, which displaces the spool 67 or 69 to compress the spring 70 or 71, which absorbs this pressure.
  • FIG. 12 illustrates a fourth embodiment of the present invention, in which the spaces 76 and 77 formed between spools 66 and 67 and 68 and 69 (not shown) are connected through a discharge conduit 79 to the valve chamber 36 which leads to the discharge port 26.
  • FIG. 13 illustrates a fifth embodiment of the present invention, which is basically the same as the embodiment illustrated in FIG. 1 except that a free piston 80 is installed independently, separate from the pressure-exerting pistons 42 and 43.
  • a valve box 81 secured to the servo valve housing 21, is provided with a valve chamber 82 having a relatively large diameter and a free piston 80 is mounted in thecharnber 82.
  • Compressed springs 83 and 84 are provided on both sides of the piston 80 and the open end of the valve hole 82 is closed by a plug 85.
  • the valve chamber 82 on the left side of the free piston 80 is connected through the port 27 to the annular concave groove 31 and the conduit 59, while the valve chamber 82'on the right side of the free piston 80 is connected through the port 28 to the annular concave groove 32'and the conduit 60.
  • the valve chamber 82 can be sufficiently enlarged to receive the free piston 80 having a relatively large diameter and accordingly with a large change in the volume of the valve chamber 82 due to the displacement of the free piston 80, it is possible to effectively absorb thesurge pressure, and the values of the spring constants of compression springs 83 and 84, which act on the free piston 80 can be so selected within a wide range that the best absorption of surge pressure may be assured.
  • the main valve member is provided with a plurality of cylindrical holes, each of which has a pressure-exerting piston, and these pressure-exerting pistons are urged against a plurality of flap valves by means of a plurality of springs and the friction between the pressureexerting pistons and flap valves can thereby effectively damp the vibrations of the flap valves.
  • a pressure proportional to the fluid pressure in the hydraulic cylinder which boosts the steering torque is exerted by the pressure-exerting pistons on the flap valves, so that the vibrations of the flap valves can be adequately damped.
  • a free piston is installed between two pressure-exerting pistons and a displacement of the free piston can absorb the surge pressure developed in the hydraulic circuit.
  • surge pressure absorbing devices such as throttle valves, spools, and free pistons are provided in the hydraulic circuit so that the surge pressure in the circuit may be absorbed.
  • the valve characteristics of the flap valve mechanism can be improved, unpleasant noise due to flap valve vibration and the drivers unpleasant feeling due to surge pressure in the hydraulic circuit can be eliminated, thereby stabilizing and enhancing the steering performance.
  • a power steering apparatus comprising a hydraulic motor for boosting manuallyapplied steering torque, which motor is supplied through a hydraulic circuit including supply and discharge passages leading to said motor,
  • control means comprising a main valve member aligned between said steering shaft members and mounted within a valve chamber to divide said chamber into two parts
  • first and second flap valves mounted within said two valve chamber parts respectively to distribute pressure fluid to said hydraulic motor selectively through relative rotation therebetween, one of said flap valves being connected to rotate with said one shaft member and the other flap valve being driven by said one shaft member through a resilient connection,
  • means for absorbing surge pressures in said hydraulic circuit including free piston means mounted in parallel with said motor between the supply and discharge passages leading to said motor, and
  • spring means biassing said pistons against said flap valves to dampen vibrations of said valves and biassing said free piston means in opposite directions.
  • Power steering apparatus as claimed in claim 1 further comprising at least one constriction in one of the supply and discharge passages leading to said hydraulic motor.
  • a power steering apparatus comprising a hydraulic motor for boosting manually applied steering torque, which motor is supplied through a hydraulic circuit including supply and discharge passages leading to said motor,
  • control means comprising a main valve member aligned between said steering shaft members and so mounted within a valve chamber as to divide said chamber into two parts,
  • first and second flap valves positioned within said two valve chamber parts respectively and adapted to distribute pressure fluid to said hydraulic motor selectively through relative rotation therebetween, one of said flap valves being connected to rotate with said one shaft member and the other flap valve being driven by said one shaft member through a resilient connection,
  • the improvement which comprises means for absorbing surge pressures in said hydraulic circuit including a free piston slidably mounted between each pair of pressureexerting pistons, one compression spring inserted between each pressure-exerting piston and the adjacent free piston, and ducts in said main valve member between said pressure-exerting pistons and said free piston connecting the passageways in said valve member to the supply and discharge passages leading to said hydraulic motor.
  • Power steering apparatus as claimed in claim 3 further comprising at least one constriction in one of the supply and discharge passages leading to said hydraulic motor.
  • a power steering apparatus comprising a hydraulic motor for boosting manually applied steering torque, which motor is sup lied through a hydraulic circult including supply and ischarge passages leading to said motor,
  • control means comprising a main valve member aligned between said steering shaft members and so mounted within a valve chamber as to divide said chamber into two parts,
  • first and second flap valves positioned within said two valve chamber parts respectively and adapted to distribute pressure fluid to said hydraulic motor selectively through relative rotation therebetween, one of said flap valves being connected to rotate with said one shaft member and the other flap valve being driven by said one shaft member through a resilient connection,
  • valve housing containing said valve chamber, and means for conducting pressure fluid from one of the parts of said valve chamber into the space formed between said two pressure-exerting pistons,
  • means for absorbing surge pressures in said hydraulic circuit including a valve body externally secured to said valve housing, an auxiliary valve chamber in said valve body, a free piston slidably mounted in said auxiliary valve chamber, and compression springs in said auxiliary valve chamber for urging said free piston in opposite directions, the spaces in the auxiliary valve chamber defined between said free piston and the ends of said auxiliary valve chamber being respectively connected to the supply and discharge passages leading to said hydraulic motor.
  • Power steering apparatus as claimed in claim 5 further comprising at least one constriction in one of the supply and discharge passages leading to said hydraulic motor.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
US858380A 1968-09-17 1969-09-16 Power steering apparatus Expired - Lifetime US3657967A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP43067056A JPS4819972B1 (enExample) 1968-09-17 1968-09-17

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US858380A Expired - Lifetime US3657967A (en) 1968-09-17 1969-09-16 Power steering apparatus

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US (1) US3657967A (enExample)
JP (1) JPS4819972B1 (enExample)
FR (1) FR2018256A1 (enExample)
GB (1) GB1249745A (enExample)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3927604A (en) * 1971-06-24 1975-12-23 Zahnradfabrik Friedrichshafen Power steering system with reaction force limiting means
US3939757A (en) * 1972-05-06 1976-02-24 Zahnradfabrik Friedrichshafen Ag Fluid power steering system with valve operator control means
US3991656A (en) * 1974-06-06 1976-11-16 Toyoda Koki Kabushiki Kaisha Servo valve device in power steering apparatus
US4048904A (en) * 1975-05-30 1977-09-20 Toyoda-Koki Kabushiki-Kaisha Servo valve device in power steering apparatus
US4220072A (en) * 1977-09-06 1980-09-02 Toyoda Koki Kabushiki Kaisha Power steering apparatus
US4339986A (en) * 1980-04-17 1982-07-20 Trw Inc. Power steering apparatus
US4627331A (en) * 1985-05-31 1986-12-09 Flo-Tork, Inc. Rotary actuator having cast piston and arcuate rack bearing
US5031714A (en) * 1989-02-10 1991-07-16 Mitsubishi Jidosha Kabushiki Kaisha Steering gear ratio changing apparatus
US5103715A (en) * 1989-03-17 1992-04-14 Techco Corporation Power steering system
US10177622B2 (en) * 2014-03-31 2019-01-08 Shenzhen Zhixing Single-Axle Two-Wheeled Driving Technology Co., Ltd. Steering motor
US10348154B2 (en) * 2014-03-31 2019-07-09 Guangdong Hua'chan Research Institute Of Intelligent Transportation System Co., Ltd Shock absorption mechanism of steering motor
WO2019135768A1 (en) * 2018-01-08 2019-07-11 Volvo Construction Equipment Ab Tunable dynamic absorber for attenutating vibration

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5852843U (ja) * 1981-09-26 1983-04-09 ミツミ電機株式会社 スライドレバ−スイツチ
JPS5879831U (ja) * 1981-11-20 1983-05-30 ミツミ電機株式会社 デイテント切換式スライドスイツチ

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2141703A (en) * 1937-11-04 1938-12-27 Stanolind Oil & Gas Co Hydraulic-pneumatic pumping system
US2684692A (en) * 1950-08-17 1954-07-27 Chrysler Corp Noise eliminator for fluid systems
US3408900A (en) * 1965-09-02 1968-11-05 Toyoda Machine Works Ltd Servo valve device in power steering gear of automobile

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2141703A (en) * 1937-11-04 1938-12-27 Stanolind Oil & Gas Co Hydraulic-pneumatic pumping system
US2684692A (en) * 1950-08-17 1954-07-27 Chrysler Corp Noise eliminator for fluid systems
US3408900A (en) * 1965-09-02 1968-11-05 Toyoda Machine Works Ltd Servo valve device in power steering gear of automobile

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3927604A (en) * 1971-06-24 1975-12-23 Zahnradfabrik Friedrichshafen Power steering system with reaction force limiting means
US3939757A (en) * 1972-05-06 1976-02-24 Zahnradfabrik Friedrichshafen Ag Fluid power steering system with valve operator control means
US3991656A (en) * 1974-06-06 1976-11-16 Toyoda Koki Kabushiki Kaisha Servo valve device in power steering apparatus
US4048904A (en) * 1975-05-30 1977-09-20 Toyoda-Koki Kabushiki-Kaisha Servo valve device in power steering apparatus
US4220072A (en) * 1977-09-06 1980-09-02 Toyoda Koki Kabushiki Kaisha Power steering apparatus
US4339986A (en) * 1980-04-17 1982-07-20 Trw Inc. Power steering apparatus
US4627331A (en) * 1985-05-31 1986-12-09 Flo-Tork, Inc. Rotary actuator having cast piston and arcuate rack bearing
US5031714A (en) * 1989-02-10 1991-07-16 Mitsubishi Jidosha Kabushiki Kaisha Steering gear ratio changing apparatus
US5103715A (en) * 1989-03-17 1992-04-14 Techco Corporation Power steering system
US10177622B2 (en) * 2014-03-31 2019-01-08 Shenzhen Zhixing Single-Axle Two-Wheeled Driving Technology Co., Ltd. Steering motor
US10348154B2 (en) * 2014-03-31 2019-07-09 Guangdong Hua'chan Research Institute Of Intelligent Transportation System Co., Ltd Shock absorption mechanism of steering motor
US10348155B2 (en) * 2014-03-31 2019-07-09 Guangdong Hua'chan Research Institute Of Intelligent Transportation System Co., Ltd Double oil passage structure of steering motor
WO2019135768A1 (en) * 2018-01-08 2019-07-11 Volvo Construction Equipment Ab Tunable dynamic absorber for attenutating vibration
US11591005B2 (en) 2018-01-08 2023-02-28 Volvo Construction Equipment Ab Tunable dynamic absorber for attenuating vibration

Also Published As

Publication number Publication date
DE1946685B2 (de) 1976-11-18
GB1249745A (en) 1971-10-13
DE1946685A1 (de) 1970-04-09
JPS4819972B1 (enExample) 1973-06-18
FR2018256A1 (enExample) 1970-05-29

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