CN103895858A - Novel undercarriage with high strength and high reliability - Google Patents
Novel undercarriage with high strength and high reliability Download PDFInfo
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Abstract
The invention provides a novel undercarriage with high strength and high reliability. The novel undercarriage comprises a 4-RRR over-constrained parallel mechanism with a linear guiding function, a cam locking mechanism and a space four-connection-rod driving mechanism, which are respectively used for realizing carrying and guiding, posture keeping and driving functions. The undercarriage can be vertically retracted and is guided by the 4-RRR over-constrained mechanism in a retracting process; when the undercarriage is completely released, a connection rod of the 4-RRR over-constrained mechanism is at a collinear position and is locked by the cam locking mechanism under the effect of the driving mechanism to form a high-order indeterminate truss; the structure of the truss has very good vertical, lateral and longitudinal carrying capabilities; when one branch pipe or two branch pipes lose efficiency, the structure also has a certain carrying capability so as to retract and release the undercarriage; a carrying and guiding mechanism, a posture keeping mechanism and a driving mechanism are separated and two sets of drives are symmetrically arranged; and when the undercarriage is released, even if one set of the drive loses the efficiency, the other set of the drive can still release the undercarriage, so that the safety and the reliability of the undercarriage are improved.
Description
Technical Field
The invention relates to an aircraft landing gear, in particular to a structure innovation design of the aircraft landing gear, and belongs to the field of aircraft design.
Background
Landing gear is an important load-bearing component of an aircraft and represents an extremely important mission during the safe taking off and landing of the aircraft. In addition to aircraft used to support the ground, it is primarily subjected to various impact loads during take-off and landing of the aircraft. Due to the fact that the airplane landing gear is subjected to large impact load and severe working environment, the failure rate of the airplane landing gear is high, statistics show that the proportion of accidents related to the landing gear structure to the total accidents of the airplane is up to 65%. Therefore, safety reliability and load capacity are two important indicators of aircraft landing gear design.
The traditional aircraft landing gear is a four-bar linkage, a driving device drives a connecting rod hinged with a fuselage to achieve the retraction function of the landing gear, when the landing gear is completely put down, two connecting rods in the four-bar linkage are collinear to achieve the attitude keeping function of the landing gear, and loads borne by the landing gear are mainly borne by a main supporting structure. As a result, the landing gear cannot function properly or even break off in the event of a failure or overload of the drive or the four-bar linkage. With the recent continuous improvement of electromechanical control techniques, new materials and new processes, the probability of landing gear failure is reduced, but it is difficult to eliminate the failure fundamentally.
To reduce the failure rate of Landing gears, many researchers have proposed innovative designs for Landing Gear mechanisms, see [ 1.s.p.grossman et al, Landing Gear, U.S. patent, patent No.: US6481668B2 [ 2.d. ducos et al, air cladding Gear of the Rocker-Arm and Deformable-parallelram Type, U.S. patent, patent number: US20130020436a1 [ 3.p. lieven et al, Front Structure of an air craft function composing binding gear, U.S. patent No.: US20130134259a1 [ 4. boeing company, nose landing gear of aircraft, chinese patent, patent No.: CN 1209406. [ 5 ] meixiye-daoyi limited, landing gear, chinese patent, patent No.: CN102791576A ]. However, the landing gear related to the patents belongs to the evolution of the traditional four-bar linkage mechanism, and cannot completely solve the defects of the traditional aircraft landing gear. And the core patents related to the landing gear are mastered by foreign enterprises, and the independent innovative design of the landing gear in China is very deficient.
Disclosure of Invention
The invention innovatively introduces a parallel mechanism into the design of an aircraft landing gear, and aims to provide the aircraft landing gear with high strength and high reliability. When the landing gear of the airplane is put down, the bearing and guiding mechanism is locked and then becomes a statically indeterminate truss structure, so that the landing gear has better bearing capacity, even if one or even two of the bearing and guiding mechanisms fail due to overload or other reasons, the landing gear still has certain bearing capacity, and the safety and reliability of the landing gear are ensured. And meanwhile, the bearing and guide mechanism, the attitude keeping mechanism and the driving mechanism are separated, and two groups of drives are symmetrically arranged, so that in the landing gear falling process, even if one group of drives fails, the landing gear can still be lowered by the other group of drives, and the safety and the reliability of the landing gear are further improved. Compared with the traditional aircraft landing gear, the invention has the remarkable advantages of high strength and high reliability.
The purpose of the invention is realized by the following technical scheme:
an aircraft landing gear is characterized by comprising a driving mechanism, a bearing and guiding mechanism, a locking mechanism and a damping mechanism; the driving mechanism is arranged between the aircraft body and the bearing and guiding mechanism, comprises a hydraulic driving device and provides power for the retraction and the extension of the undercarriage; the bearing and guiding mechanism is arranged between the driving mechanism and the damping mechanism, comprises at least two same non-coplanar kinematic chains and is used for realizing the linear guidance of the landing gear and the vertical retraction and extension; the kinematic chain consists of a revolute pair R; the shock absorption mechanism comprises a shock absorber and a pneumatic tire, and provides buffer for the landing and taxiing of the airplane.
The undercarriage is characterized by further comprising a locking mechanism, wherein the locking mechanism is positioned in the bearing and guiding mechanism and used for locking the relative rotation of the revolute pair kinematic chain of the bearing and guiding mechanism when the undercarriage is put down.
Preferably, the kinematic chain composed of revolute pairs R is in particular an RRR kinematic chain (I, II, III, IV), the axes of the three revolute pairs R in each RRR kinematic chain being parallel to each other.
More preferably, each branched chain of the RRR kinematic chain comprises an upper end connecting rod (5a), an end cover (9a), a lower end connecting rod (10a), a first pin shaft (11a), a groove and a bolt (12 a); the upper end connecting rod (5a) is a stepped hollow rod, the aperture of the part close to the lower end connecting rod (10a) is small, and the aperture of the part close to the other end is large; the lower end connecting rod (10a) can rotate relative to the upper end connecting rod (5a), and the end cover (9a) is fixed with the upper end connecting rod (5a) through a bolt (12a) to play a role in fixing the lower end connecting rod (10 a); a groove is formed in the top of one side, close to the upper end connecting rod (5a), of the lower end connecting rod (10 a); the lower end connecting rod (10a) is hinged with the damping mechanism (4) through a first pin shaft (11 a); the locking mechanism is arranged in a stepped hole of the upper end connecting rod (5a) and comprises a second pin shaft (7a), a cam (6a), a push rod (8a) and a spring (13 a); the second pin shaft (7a) is fixed with the airplane body, the cam (6a) and the second pin shaft (7a) are positioned and fixed through a flat key or a screw, and the upper end connecting rod (5a) can rotate relative to the second pin shaft (7 a); one side of the ejector rod (8a) is contacted with the cam through the roller, and meanwhile, the ejector rod (8a) is in clearance fit with the stroke of the smaller hole end of the upper end connecting rod (5 a); a spring (13a) is placed in a larger hole in the upper end link (5a), and one end thereof is fixed to the jack (8a) for keeping the jack (8a) in contact with the cam (6a) at all times.
The undercarriage is characterized in that the upper end connecting rod (5a) rotates in the lowering process of the undercarriage to drive the ejector rod (8a) to rotate around the cam (6a), the cam (6a) further pushes the ejector rod (8a) to move axially along the upper end connecting rod (5a), when the undercarriage is fully lowered, the ejector rod (8a) is just located at the maximum stroke of the cam (7a), the tail end of the ejector rod (8a) is in contact with the groove of the lower end connecting rod (10a), and therefore the upper end connecting rod (5a) and the lower end connecting rod (10a) are prevented from rotating relatively, and the working posture of the undercarriage is kept.
Preferably, the hydraulic driving device comprises a hydraulic cylinder (1a, 1b), a driving rod and a connecting rod, the hydraulic cylinder is fixed with the airplane body, the driving rod is connected with the connecting rod through a ball head auxiliary link, and the other side of the connecting rod (3a, 3b, 3c, 3d) is connected with an upper end connecting rod (5a) in the RRR kinematic chain (I, II, III, IV) through the ball head auxiliary link.
Wherein, the number of the RRR kinematic chains is 3. Preferably, the number of RRR kinematic chains is specifically 4. The 4 RRR kinematic chains are respectively numbered as I, II, III and IV; taking the advancing direction of the airplane as the x direction, the gravity direction as the z direction, and the direction vertical to the xz plane as the y direction; the central point of the damping mechanism is point o, the axes of three revolute pairs R in each RRR kinematic chain are parallel to a plane xoy, the branched chains I and II and the branched chains IV and III are symmetrically arranged about a plane xoz respectively, and the branched chains I and IV and the branched chains II and III are symmetrically arranged about a plane yoz respectively.
The hydraulic cylinders are two, the driving rods are two, and the connecting rods are four; the two hydraulic cylinders are symmetrically arranged in front and back directions relative to the advancing direction of the airplane, two sides of each driving rod (2a, 2b) are respectively linked with the two connecting rods (3a, 3d, or 3b, 3c) through ball head pairs, and the other side of each connecting rod (3a, 3b, 3c, 3d) is respectively linked with the upper end connecting rod in the RRR kinematic chain (I, II, III, IV) through the ball head pairs.
Preferably, the hydraulic drive mechanism is a spatial four-bar linkage mechanism, two links on two sides of the drive rods (2a, 2b) in the same group of drives are symmetrical left and right relative to the advancing direction of the airplane, and the drive rods (2a, 2b) can only move back and forth along the advancing direction of the airplane.
After the mechanism is locked, the bearing and guiding mechanism consisting of 4 RRR kinematic chains becomes a statically indeterminate truss structure.
Compared with the existing aircraft landing gear, the invention has the following outstanding advantages: firstly, the invention provides a brand-new undercarriage retraction device, which comprises a brand-new bearing and guiding mechanism and a locking mechanism, and the invention greatly contributes to the prior art. Secondly, the bearing and guide mechanism, the locking mechanism and the driving mechanism of the undercarriage are mutually separated, and two groups of drives are symmetrically arranged, so that a redundant design is realized in the undercarriage putting-down process, even if one group of drives fails, the other group of drives can still realize the undercarriage putting-down, and the reliability of the undercarriage is improved; after the bearing and guide mechanism is locked by the locking mechanism, the bearing and guide mechanism becomes a statically indeterminate truss structure, the truss structure has better vertical, lateral and longitudinal bearing capacity, and even if one or even two kinematic chains fail due to impact load or other reasons, the truss structure can still realize bearing, so that the landing gear is ensured to be completely failed or even broken. The landing gear therefore has the significant advantages of high strength and high reliability over conventional landing gears.
Drawings
FIG. 1a fully down schematic view of a landing gear
FIG. 2 is a schematic view of the kinematic chain I
FIG. 3 fully stowed view of landing gear
FIG. 4 is a schematic view of the landing gear stowed and lowered attitude during failure of the kinematic chain I
FIG. 5 is a schematic view of the landing gear retraction and lowering attitude in the event of failure of the kinematic chains I and II
FIG. 6A schematic representation of landing gear lowering in the event of failure of the actuator 1b
FIG. 72-RRR mechanism motion schematic
FIG. 8 is a schematic diagram of a cam locking mechanism
FIG. 9 is a general schematic of the present invention
Detailed Description
The structure, principle and specific embodiments of the present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1, the carrying and guiding means comprise four identical RRR (R stands for revolute pair) kinematic chains, respectively numbered i, ii, iii, iv, the three revolute pair axes of each RRR kinematic chain being parallel to each other and to the plane xoy, and the branched chains i, ii and the branched chains iv, iii being respectively symmetrical with respect to the plane xoz; the branched chains I and IV and the branched chains II and III are respectively symmetrical about a plane yoz, and four RRR kinematic chains are hinged with the damping system (4) by adopting revolute pairs.
Taking the branched chain I as an example, as shown in fig. 2, the branched chain I mainly comprises an upper end connecting rod (5a), a cam (6a), a pin shaft (7a), a push rod (8a), an end cover (9a), a lower end connecting rod (10a), a pin shaft (11a), a bolt (12a) and a spring (13 a). Wherein the pin shaft (7a) is fixed with the airplane body (not shown in the figure), and the cam (6a) is fixed with the pin shaft (7a) through a flat key or a screw; the upper end connecting rod (5a) is a stepped hollow rod, the aperture of the part close to the lower end connecting rod (10a) is small, the aperture of the part close to the pin shaft (7a) is large, and the upper end connecting rod (5a) can rotate relative to the pin shaft (7 a); the lower end connecting rod (10a) can rotate relative to the upper end connecting rod (5a), and the end cover (9a) is fixed with the upper end connecting rod (5a) through a bolt (12a) to play a role in fixing the lower end connecting rod (10 a); a groove (not shown in the figure) is arranged at the top of one side of the lower end connecting rod (10a) close to the upper end connecting rod (5 a); the lower end connecting rod (10a) is hinged with the damping system (4) through a pin shaft (11 a). The locking mechanism is arranged in a stepped hole of the upper end connecting rod (5a) and consists of a cam (6a), a mandril (8a) and a spring (13a), and the spring (13a) is used for keeping the mandril to be always in contact with the cam (6 a). Two groups of driving mechanisms are symmetrically arranged about a plane yoz, a hydraulic cylinder (1a) or (1b) is fixed with an airplane body (not shown in the figure), two sides of a driving rod (2a) or (2b) are connected with connecting rods (3a, 3d) or connecting rods (3b, 3c) through ball head pairs, and the other sides of the connecting rods (3a, 3b, 3c, 3d) are connected with upper-end connecting rods in a kinematic chain (I, II, III, IV) through the ball head pairs respectively. The drive mechanism is a spatial four-bar mechanism, and two bars in the same set of drives, the bars (3a, 3d) and the bars (3b, 3c), are symmetrical about a plane xoz, and the drive bars (2a, 2b) can only reciprocate in the x-axis direction.
The bearing and guiding mechanism can achieve the functions of retraction and extension and bearing of the undercarriage, the undercarriage can guide the undercarriage damping system (4) to move vertically to be retracted into the cabin under the action of the driving system in the retraction and extension process, two connecting rods of each kinematic chain are collinear and locked through the locking mechanism when the undercarriage is put down, relative rotation of the two connecting rods is avoided, and a statically indeterminate truss structure is formed. The kinematic principle of the carrying and guiding mechanism is first described.
As shown in FIG. 7, two RRR kinematic chains A1B1C1And A2B2C2Are respectively located at pi1Plane, pi2In the plane, the axes of the three revolute pairs in the kinematic chain are parallel to each other and are always perpendicular to the corresponding plane. Pi1Plane and pi2The intersection of the planes is a straight line PQ. With kinematic pair A1Establishing a coordinate system A for the origin1x1y1z1，z1Axis perpendicular to pi1And (4) a plane. With a kinematic pair B1And C1Respectively has coordinates of B1(xB1,yB1,0)、C1(xC1,yC1And 0), the motion spirals of the three motion pairs are respectively:
$A1=[001000]T，
$B1=[001-yB1xB10]T，
$C1=[001-yC1xC10]T。
then the transiently moving helix at the end of the kinetic chain can be expressed as:
$1=k1$A1+k2$B1+k3$C1=[00k1+k2+k3-k2yB1-k3yC1k2xB1+k3xC10]T
therefore, when k is1+k2+k3Not equal to 0 $1Represents a winding z1Rotation of the shaft; when k is1+k2+k3K is =02yB1+k3yC1、k2xB1+k3xC1Not equal to zero at the same time, $1Is shown at x1A1y1Translational movement in the plane. Therefore, the kinematic chain A1B1C1Is constrained to lie along z1Movement of and about axis x1、y1Rotation of the shaft. That is, Yun Gong A1B1C1Can always only be at pi1In-plane motion.
Similarly, Yugong is connected with A2B2C2Can always only be at pi2In-plane motion. Then, when the kinematic chain A1B1C1And A2B2C2The tail ends of the mechanisms are the same component, namely the 2-RRR mechanism is formed, the tail ends of the mechanisms need to be at pi simultaneously1Plane and pi2In-plane motion. The end of the mechanism can only move along the intersection line PQ of the two planes when the two planes are not parallel. That is, the 2-RRR mechanism has a straight guide function. If two RRR kinematic chains are added, so that the intersecting lines of the planes where the four RRR kinematic chains are located are all parallel or coincident, the tail end of the formed 4-RRR mechanism can only do linear motion along the intersecting lines of the planes. Therefore, the 4-RRR mechanism also has a straight guide function. Each RRR kinematic chain may provide 3 end constraints, then four RRR kinematic chains may provide 12 end constraints, while at the same time the mechanism end has one degree of translational freedom, i.e., 5 degrees of freedom to constrain. Since the number of constraints provided by the ends of the branches is greater than the number of constraints, the 4-RRR mechanism is an over-constrained parallel mechanism.
When the undercarriage is put down, on one hand, the driving system is locked, and the upper end connecting rod is ensured not to rotate; on the other hand, the locking mechanism arranged together with the upper end connecting rod can lock the upper end connecting rod and the lower end connecting rod, so that relative rotation is avoided. Therefore, when the undercarriage is put down, each RRR kinematic chain can be equivalent to a stress rod, and two ends of the RRR kinematic chain are respectively linked with the airplane body and the damping system through revolute pairs. Each branch chain can bear forces and moments in three directions when the landing gear is put down, namely pulling/pressing force along the axial direction, lateral acting force and bending moment perpendicular to the axial line. The damping system (4) is subjected to 12 unknown restraining forces and moments of the four branched chains in total, and 6 equation equations can be established according to the damping system stress and moment balance. Therefore, the static number of times of the load-bearing truss structure when the landing gear is down is 12-6=6, and the truss structure has high strength.
Assuming that one of the arms of the landing gear load and guidance mechanism fails, the other three arms (including the drive and lock mechanisms) are intact, as shown in figure 4. The mechanism can be regarded as a 3-RRR mechanism, which, as can be seen from the kinematic principles described above, still has a linear guiding function and therefore the undercarriage still has a retraction function; when the landing gear is put down, the 3-RRR mechanism is locked to form a truss structure, and the number of times of statics of the structure is 3 x 3-6=3, so that the structure still has good bearing capacity. Assuming that two of the arms of the landing gear load and guide mechanism fail, the other two arms (including the drive and lock mechanisms) are intact, as shown in figure 5. The mechanism can be regarded as a 2-RRR mechanism with a linear guide function, so that the undercarriage still has a retraction function; when the landing gear is put down, the 2-RRR mechanism is locked to form a truss structure, the statically definite number of the structure is 2 x 3-6=0, and therefore the structure still has a certain bearing capacity. In conclusion, the undercarriage has high strength and high reliability, and can ensure that the undercarriage can still realize the functions of bearing, retracting and releasing under extreme conditions.
Because the connecting rods of the four branched chains of the landing gear in the down state are collinear, the upper connecting rods of the four branched chains need to move simultaneously in order to realize the retraction of the landing gear, and therefore two groups of driving mechanisms are symmetrically arranged, and each group of driving mechanisms drives two branched chains, as shown in fig. 1 and 2. In the landing gear lowering process, the connecting rods are not in a collinear state, and the landing gear can be lowered under the action of dead weight on the assumption that the friction of the revolute pair or the vertical resistance generated by the friction is not considered to be smaller than the dead weight of the landing gear. The two groups of drives are symmetrically arranged, so that a redundant design is realized, the working reliability of the undercarriage is improved, and the undercarriage can be put down even if one group of drives fails, as shown in fig. 6; the landing gear can be put down through self weight even through design, and therefore the landing gear can still work under extreme conditions that two sets of drives fail simultaneously. This further improves the operational reliability of the landing gear by providing redundant drives. It should be noted, however, that if one of the drives fails, the landing gear needs to be serviced to ensure that both drives are operating properly, otherwise the landing gear may not be retracted properly.
The cam locking mechanism is schematically shown in fig. 8, a cam (6a) is fixed relative to a machine body, one end of a push rod (8a) is contacted with the cam (6a) through a roller, the other end of the push rod is in stroke clearance fit with an upper end connecting rod (5a), and a spring (13a) is arranged between the push rod (8a) and the cam (6a) and has the function of enabling the roller to be always contacted with the cam (6 a). When the undercarriage is in a retracted state, the roller is in contact with the cam base circle, the compression amount of the spring is small, and a large gap exists between the top end of the ejector rod (8a) and the lower end connecting rod (10 a); when the undercarriage is completely put down, the roller is in contact with the highest point of the cam, the compression amount of the spring is large, and the top end of the ejector rod (8a) is just attached to the lower end connecting rod (10a) and is positioned in the groove of the lower end connecting rod. In the landing gear lowering process, the gap between the top end of the ejector rod (8a) and the lower end connecting rod (10a) is smaller and smaller until the top end of the ejector rod and the lower end connecting rod are attached; during the retraction of the landing gear, the clearance between the top end of the mandril (8a) and the lower end connecting rod (10a) is larger and larger. And if the radius of the cam base circle is R and the distance between the highest point and the center of the base circle is R, the clearance between the top end of the ejector rod (8a) and the lower end connecting rod (10a) is R-R when the undercarriage is in a retracted state.
Compared with the existing aircraft landing gear, the landing gear provided by the invention has the remarkable advantages of high strength and high reliability by introducing the over-constrained parallel mechanism and the redundant drive design, can greatly improve the safety and reliability of the aircraft landing gear, reduces the failure rate of the landing gear, and has wide application prospect and great application value.
The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and substitutions can be made or any combinations of the claims can be recombined without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.
Claims (12)
1. An aircraft landing gear is characterized by comprising a driving mechanism, a bearing and guiding mechanism, a locking mechanism and a damping mechanism; wherein,
the driving mechanism is arranged between the aircraft body and the bearing and guiding mechanism, comprises a hydraulic driving device and provides power for the retraction and the extension of the undercarriage;
the bearing and guiding mechanism is arranged between the driving mechanism and the damping mechanism, comprises at least two same non-coplanar kinematic chains and is used for realizing the linear guidance of the landing gear and the vertical retraction and extension; the kinematic chain consists of a revolute pair R;
the shock absorption mechanism comprises a shock absorber and a pneumatic tire, and provides buffer for the landing and taxiing of the airplane.
2. An aircraft landing gear according to claim 1, further comprising a locking mechanism located within the carrier and guide mechanism for locking the relative rotation of the revolute kinematic chain of the carrier and guide mechanism when the landing gear is down.
3. Aircraft landing gear according to claim 1 or 2, wherein said kinematic chains consisting of revolute pairs R are in particular RRR kinematic chains (I, II, III, IV), the axes of the three revolute pairs R of each RRR kinematic chain being parallel to each other.
4. The aircraft landing gear of claim 3, wherein each branch of the RRR kinematics chain comprises an upper end link (5a), an end cap (9a), a lower end link (10a), a groove, a first pin (11a), and a bolt (12 a); the upper end connecting rod (5a) is a stepped hollow rod, the aperture of the part close to the lower end connecting rod (10a) is small, and the aperture of the part close to the other end is large; the lower end connecting rod (10a) can rotate relative to the upper end connecting rod (5a), and the end cover (9a) is fixed with the upper end connecting rod (5a) through a bolt (12a) to play a role in fixing the lower end connecting rod (10 a); a groove is formed in the top of one side, close to the upper end connecting rod (5a), of the lower end connecting rod (10 a); the lower end connecting rod (10a) is hinged with the damping mechanism (4) through a first pin shaft (11 a);
the locking mechanism is arranged in a stepped hole of the upper end connecting rod (5a) and comprises a second pin shaft (7a), a cam (6a), a push rod (8a) and a spring (13 a); the second pin shaft (7a) is fixed with the airplane body, the cam (6a) and the second pin shaft (7a) are positioned and fixed through a flat key or a screw, and the upper end connecting rod (5a) can rotate relative to the second pin shaft (7 a); one side of the ejector rod (8a) is contacted with the cam through the roller, and meanwhile, the ejector rod (8a) is in clearance fit with the stroke of the smaller hole end of the upper end connecting rod (5 a); a spring (13a) is placed in a larger hole in the upper end link (5a), and one end thereof is fixed to the jack (8a) for keeping the jack (8a) in contact with the cam (6a) at all times.
5. The aircraft landing gear according to claim 4, wherein the upper end connecting rod (5a) rotates to drive the ejector rod (8a) to rotate around the cam (6a) during landing gear lowering, the cam (6a) further pushes the ejector rod (8a) to move axially along the upper end connecting rod (5a), when the landing gear is fully lowered, the ejector rod (8a) is just located at the maximum stroke of the cam (7a), and the tail end of the ejector rod (8a) is in contact with the groove of the lower end connecting rod (10a), so that the upper end connecting rod (5a) and the lower end connecting rod (10a) are prevented from rotating relatively, and the working posture of the landing gear is maintained.
6. An aircraft landing gear according to claim 4, wherein the hydraulic drive means comprises a hydraulic cylinder (1a, 1b) fixed to the aircraft fuselage, a drive rod linked to the link by a ball-nose secondary, and a link (3a, 3b, 3c, 3d) linked on the other side to the upper end link (5a) of the RRR kinematics chain (I, II, III, IV) by a ball-nose secondary.
7. Aircraft landing gear according to one of claims 4 to 6, wherein the number of RRR kinematics chains is in particular 3.
8. Aircraft landing gear according to one of claims 4 to 6, wherein the number of RRR kinematics chains is in particular 4.
9. An aircraft landing gear according to claim 8 in which the 4 RRR kinematics chains are numbered i, ii, iii, iv; taking the advancing direction of the airplane as the x direction, the gravity direction as the z direction, and the direction vertical to the xz plane as the y direction; the central point of the damping mechanism is point o, the axes of three revolute pairs R in each RRR kinematic chain are parallel to a plane xoy, the branched chains I and II and the branched chains IV and III are symmetrically arranged about a plane xoz respectively, and the branched chains I and IV and the branched chains II and III are symmetrically arranged about a plane yoz respectively.
10. The aircraft landing gear of claim 8, wherein the number of hydraulic cylinders is two, the number of drive rods is two, and the number of links is four; the two hydraulic cylinders are symmetrically arranged in front and back directions relative to the advancing direction of the airplane, two sides of each driving rod (2a, 2b) are respectively linked with the two connecting rods (3a, 3d, or 3b, 3c) through ball head pairs, and the other side of each connecting rod (3a, 3b, 3c, 3d) is respectively linked with the upper end connecting rod in the RRR kinematic chain (I, II, III, IV) through the ball head pairs.
11. Aircraft landing gear according to claim 10, wherein the hydraulic drive mechanism is a spatial four-bar linkage, and the two links on either side of the drive rod (2a, 2b) in the same set of drives are bilaterally symmetric with respect to the aircraft forward direction, and the drive rod (2a, 2b) can only move back and forth in the aircraft forward direction.
12. The aircraft landing gear of claim 8, wherein the load and guide mechanism of 4 RRR kinematics chains is an overconstrained parallel mechanism that, when locked, is an statically indeterminate truss structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410110736.4A CN103895858B (en) | 2014-03-24 | 2014-03-24 | High strength and high reliability undercarriage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410110736.4A CN103895858B (en) | 2014-03-24 | 2014-03-24 | High strength and high reliability undercarriage |
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| CN103895858A true CN103895858A (en) | 2014-07-02 |
| CN103895858B CN103895858B (en) | 2016-01-20 |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104210654A (en) * | 2014-08-26 | 2014-12-17 | 中国直升机设计研究所 | Wheel lock indicator for landing gear |
| CN104309800A (en) * | 2014-08-26 | 2015-01-28 | 中国直升机设计研究所 | Undercarriage wheel lock |
| CN105644774A (en) * | 2016-02-02 | 2016-06-08 | 吴燕 | Multi-rotor flight vehicle undercarriage based on Stewart six-degree-of-freedom parallel mechanism |
| CN106516087A (en) * | 2016-10-21 | 2017-03-22 | 清华大学 | Novel high-strength high-compactness lightweight aircraft landing gear |
| CN107792370A (en) * | 2017-10-30 | 2018-03-13 | 张罗悦 | A kind of independent-suspension damping device of unmanned plane jet pipe |
| CN107985562A (en) * | 2017-12-07 | 2018-05-04 | 清华大学 | A kind of lightweight compact formula undercarriage |
| CN108001670A (en) * | 2017-11-21 | 2018-05-08 | 燕山大学 | Plane-parallel type aircraft main landing gear |
| CN108128443A (en) * | 2017-12-28 | 2018-06-08 | 成都优艾维智能科技有限责任公司 | Non-virtual position impact-resistant quick-release type electric retractable undercarriage |
| CN110834719A (en) * | 2018-08-17 | 2020-02-25 | 中国飞机强度研究所 | Bionic leg undercarriage system |
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| FR2687123A1 (en) * | 1992-02-11 | 1993-08-13 | Eram | Retractable landing gear of an aircraft, especially for a helicopter |
| CN2255403Y (en) * | 1995-10-26 | 1997-06-04 | 徐裕龄 | Alighting carriage for plane |
| CN101065292A (en) * | 2004-08-30 | 2007-10-31 | 梅西尔-道蒂（美国）公司 | Dual brace-determinate landing gear |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| FR2687123A1 (en) * | 1992-02-11 | 1993-08-13 | Eram | Retractable landing gear of an aircraft, especially for a helicopter |
| CN2255403Y (en) * | 1995-10-26 | 1997-06-04 | 徐裕龄 | Alighting carriage for plane |
| CN101065292A (en) * | 2004-08-30 | 2007-10-31 | 梅西尔-道蒂（美国）公司 | Dual brace-determinate landing gear |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104210654A (en) * | 2014-08-26 | 2014-12-17 | 中国直升机设计研究所 | Wheel lock indicator for landing gear |
| CN104309800A (en) * | 2014-08-26 | 2015-01-28 | 中国直升机设计研究所 | Undercarriage wheel lock |
| CN104309800B (en) * | 2014-08-26 | 2017-08-18 | 中国直升机设计研究所 | A kind of undercarriage wheel lock |
| CN105644774A (en) * | 2016-02-02 | 2016-06-08 | 吴燕 | Multi-rotor flight vehicle undercarriage based on Stewart six-degree-of-freedom parallel mechanism |
| CN105644774B (en) * | 2016-02-02 | 2017-10-20 | 绍兴俪泰纺织科技有限公司 | A kind of multi-rotor aerocraft undercarriage based on Stewart six-degree-of-freedom parallel connection mechanisms |
| CN106516087A (en) * | 2016-10-21 | 2017-03-22 | 清华大学 | Novel high-strength high-compactness lightweight aircraft landing gear |
| CN107792370A (en) * | 2017-10-30 | 2018-03-13 | 张罗悦 | A kind of independent-suspension damping device of unmanned plane jet pipe |
| CN108001670A (en) * | 2017-11-21 | 2018-05-08 | 燕山大学 | Plane-parallel type aircraft main landing gear |
| CN107985562A (en) * | 2017-12-07 | 2018-05-04 | 清华大学 | A kind of lightweight compact formula undercarriage |
| CN108128443A (en) * | 2017-12-28 | 2018-06-08 | 成都优艾维智能科技有限责任公司 | Non-virtual position impact-resistant quick-release type electric retractable undercarriage |
| CN108128443B (en) * | 2017-12-28 | 2023-12-05 | 成都优艾维智能科技有限责任公司 | Virtual-position-free impact-resistant quick-release type electric retractable landing gear |
| CN110834719A (en) * | 2018-08-17 | 2020-02-25 | 中国飞机强度研究所 | Bionic leg undercarriage system |
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| CN103895858B (en) | 2016-01-20 |
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