An active variable steering system and steering method implemented based on a planetary gear set mechanism

Abstract

The present invention discloses an active variable steering system implemented based on a planetary gear set mechanism, which includes a steering device; a double-row planetary gear set device, which includes a first sun gear, a first planet gear, a gear shaft, a second sun gear, a second planet gear, a planet carrier and a ring gear; wherein, the first sun gear is fixedly installed at one end of the input shaft; the gear shaft is rotatably sleeved at the other end of the input shaft; the second sun gear is fixedly installed at one end of the gear shaft and is simultaneously rotatably sleeved on the input shaft; the first planet gear meshes and drives with the first sun gear, and the second planet gear simultaneously meshes and drives with the first planet gear, the second sun gear and the ring gear; an output shaft; and two locking devices for selectively locking the planet carrier or the second sun gear to stop rotating. The present invention discloses an active variable steering method implemented based on a planetary gear set mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of steering systems, and particularly relates to an active variable steering system and a steering method implemented based on a planetary gear set mechanism. Background Art

[0002] Regardless of whether the vehicle is traveling at low speed or high speed, the steering wheel to steering wheel angle ratio of the conventional automotive steering system is always fixed, and it is difficult to balance the lightness and stability of the steering system. The active steering system has a more direct steering ratio and can provide an ideal steering wheel angle at any vehicle speed, ensuring that the steering control becomes more flexible within a lower vehicle speed range; while within a higher vehicle speed range, the steering system control becomes more stable and reliable. The active steering system can take into account both the lightness and stability of the steering system control.

[0003] The active steering system also corrects the input front wheel steering angle according to the vehicle speed to better ensure the comfort and stability of the driving control direction without affecting the steering accuracy. Therefore, the active steering system can ensure that the vehicle can provide an ideal steering control at any speed, achieving the most suitable balance between lightness and stability. Summary of the Invention

[0004] Based on the above technical problems, the present invention designs and develops an active variable steering system implemented based on a planetary gear set mechanism. The object of the present invention is to provide an active steering system with a simple structure, good stability, and easy to control and implement.

[0005] The present invention designs and develops an active variable steering method implemented based on a planetary gear set mechanism. The object of the present invention is to achieve different steering ratios through the cooperation of a set of planetary gear mechanisms to ensure that the ratio of the steering wheel input angle to the steering wheel angle is always the optimal steering ratio at different vehicle speeds.

[0006] The technical solution provided by the present invention is as follows:

[0007] An active variable steering system implemented based on a planetary gear set mechanism, comprising:

[0008] A steering device, which includes an input shaft for inputting steering power;

[0009] A double-row planetary gear set device, which includes a first sun gear, a first planet gear, a gear shaft, a second sun gear, a second planet gear, a planet carrier, and a ring gear;

[0010] Wherein, the first sun gear is fixedly installed at one end of the input shaft; the gear shaft is rotatably sleeved at the other end of the input shaft; the second sun gear is fixedly installed at one end of the gear shaft and is simultaneously rotatably sleeved on the input shaft; both ends of the planet carrier are respectively rotatably sleeved at one end of the gear shaft and the input shaft; the first planet gear and the second planet gear are rotatably sleeved on the planet carrier; the first planet gear meshes and drives with the first sun gear, and the second planet gear simultaneously meshes and drives with the first planet gear, the second sun gear and the ring gear; there is an installation spacing of about 3 mm to 5 mm between the first sun gear and the second sun gear;

[0011] An output shaft, which is fixedly connected to the ring gear and is used for outputting the steering power;

[0012] Two locking devices, which are respectively sleeved on the outer side of the planet carrier and the outer side of the other end of the gear shaft, and are used for selectively locking the planet carrier or the second sun gear to stop rotating;

[0013] Wherein, the locking device includes:

[0014] Two relatively symmetrically arranged arc-shaped support plates, one end of which is simultaneously fixedly installed on the transmission gearbox;

[0015] Two relatively symmetrically arranged friction plates, which are respectively fixedly installed on the inner sides of the arc-shaped support plates in one-to-one correspondence;

[0016] Wherein, the inner and outer arc shapes of the friction plate respectively coincide with the outer circle of the corresponding locking component and the inner shape of the support plate, and the minimum inner ring radius of the support plate is greater than the inner ring radius of the friction plate;

[0017] A tensioning device, which is used for locking the planet carrier or the second sun gear by the tensioning action of the tensioning device in the initial working state;

[0018] A two-way locking device oil cylinder, which is arranged between the other ends of the arc-shaped support plates, and the pistons on both sides in the two-way locking device oil cylinder are respectively simultaneously connected to the other ends of the arc-shaped support plates.

[0019] Preferably, it further includes:

[0020] A support pin, which is fixedly installed on the transmission gearbox;

[0021] Wherein, one end of the arc-shaped support plate is simultaneously fixedly installed on the transmission gearbox through the support pin, and one end of the arc-shaped support plate can rotate around the support pin; and

[0022] A support box, which is fixedly installed on the vehicle chassis;

[0023] Wherein, the input shaft and the output shaft are rotatably supported on the cover plates at both ends of the support box.

[0024] Preferably, the tensioning device is a tension spring, and both ends thereof are simultaneously connected to the other end of the arc-shaped support plate.

[0025] Preferably, the tensioning device comprises:

[0026] Two first helical springs, one end of each of which abuts against the other end of the arc-shaped support plate respectively in a one-to-one correspondence;

[0027] Two supports, which are respectively arranged corresponding to the two helical springs, the supports are fixedly installed on the transmission gearbox, and the other ends of the helical springs are respectively fixedly connected to the supports in a one-to-one correspondence.

[0028] Preferably, the planet carrier comprises:

[0029] A first planet carrier;

[0030] A second planet carrier, which is arranged opposite to the first planet carrier;

[0031] A first planet pin, one end of which is fixedly connected to the first planet carrier, and the first planet gear can rotate around the first planet pin;

[0032] A second planet pin, both ends of which are respectively fixedly connected to the first planet carrier and the second planet carrier, and the second planet gear can rotate around the second planet pin;

[0033] Wherein, the locking device is sleeved outside the second planet carrier; there is an installation spacing of about 2 mm between the second planet carrier and the second sun gear, and between the first planet carrier and the first sun gear.

[0034] Preferably, the two-way locking cylinder comprises:

[0035] A cylinder block;

[0036] A protective cover, which forms a sealed oil cavity with the cylinder block in a closed manner;

[0037] A second helical spring, which is arranged in the sealed oil cavity;

[0038] Two gaskets, which are symmetrically arranged on both sides of the second helical spring, one side of each gasket is respectively connected to both ends of the second helical spring, and the other side is connected to one side of the piston;

[0039] Two top blocks, one side of each of which is connected to the other side of the piston, and the other side is respectively connected to the arc-shaped support plate.

[0040] An active steering method with variable steering ratio implemented based on a planetary gear set mechanism, characterized in that the active variable steering system implemented based on the planetary gear set mechanism is used, including:

[0041] When the vehicle is starting or driving at a low speed, the transmission gearbox is in the initial working state, and the lockers are all in the locked state. At this time, the planet carrier and the second sun gear are both in the locked state;

[0042] When the vehicle is driving at a medium speed, oil is injected into the locker cylinder on the planet carrier until the planet carrier and the locker on the planet carrier are completely separated. At the same time, the oil in the locker cylinder on the second sun gear flows back to the oil storage tank. At this time, the second sun gear is in the locked state;

[0043] When the vehicle is driving at a high speed, oil is injected into the locker cylinder on the second sun gear until the second sun gear and the locker on the second sun gear are completely separated. At the same time, the oil in the locker cylinder on the planet carrier flows back to the oil storage tank. At this time, the planet carrier is in the locked state.

[0044] Preferably, it further includes:

[0045] When the vehicle drives from a low speed to a medium speed, oil is injected into the locker cylinder on the planet carrier until the planet carrier and the locker on the planet carrier are completely separated. At this time, the second sun gear is in the locked state;

[0046] When the vehicle drives from a medium speed to a high speed, oil is injected into the locker cylinder on the second sun gear until the second sun gear and the locker on the second sun gear are completely separated. At the same time, the oil in the locker cylinder on the planet carrier flows back to the oil storage tank. At this time, the planet carrier is in the locked state;

[0047] When the vehicle drives from a high speed to a medium speed, oil is injected into the locker cylinder on the planet carrier until the planet carrier and the locker on the planet carrier are completely separated. At the same time, the oil in the locker cylinder on the second sun gear flows back to the oil storage tank. At this time, the second sun gear is in the locked state;

[0048] When the vehicle drives from a medium speed to a low speed, the oil in the locker cylinder on the planet carrier flows back to the oil storage tank. At this time, the planet carrier and the second sun gear are both in the locked state.

[0049] Preferably, it further includes:

[0050] When the vehicle drives from a low speed to a high speed, oil is injected into the locker cylinder on the second sun gear until the second sun gear and the locker on the second sun gear are completely separated. At this time, the planet carrier is in the locked state;

[0051] When the vehicle travels from high speed to low speed, the hydraulic oil in the locking cylinder on the second sun gear flows back into the fuel tank. At this time, the planet carrier and the second sun gear are both in a locked state.

[0052] Preferably, the constraint relationship of the double-row planetary gear set device satisfies:

[0053]

[0054] Among them,

[0055] In the formula, n 202 is the rotational speed of the second sun gear, n 203 is the rotational speed of the ring gear, n 201 is the rotational speed of the planet carrier, n 204 is the rotational speed of the first sun gear, z 202 is the number of teeth of the second sun gear, z 203 is the number of teeth of the ring gear, z 204 is the number of teeth of the first sun gear; and

[0056] The transmission ratio i of the transmission gearbox is based on the transmission ratio relationship corresponding to the vehicle speed change range as

[0057]

[0058] In the formula, u is the vehicle speed, and umin and umax are the upper and lower critical vehicle speed values of the intermediate vehicle speed during vehicle travel.

[0059] The beneficial effects of the present invention compared with the prior art: The active steering system with variable steering ratio has the characteristics of simple structure, convenient operation, and good stability. By the motion constraint of the double-row planetary gear set mechanism, the variable steering ratio requirements at different vehicle speeds are realized, so that the vehicle steering ratio is always in an ideal state with the change of vehicle speed, in order to ensure the handling ease at low speeds and the handling stability at high speeds of the vehicle steering system. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is the structural assembly layout diagram of the active variable steering system implemented based on the planetary gear set mechanism of the present invention.

[0061] Figure 2 is the structural diagram of the support box of the active variable steering system implemented based on the planetary gear set mechanism of the present invention.

[0062] Figure 3 is the internal structural diagram of the transmission gearbox of the active variable steering system implemented based on the planetary gear set mechanism of the present invention.

[0063] Figure 4It is the structure diagram of the transmission gearbox bottom shell of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0064] Figure 5 It is the structure diagram of the transmission gearbox cover of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0065] Figure 6 It is the visual view of the planetary gear set of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention Figure 1 。

[0066] Figure 7 It is the visual view of the planetary gear set of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention Figure 2 。

[0067] Figure 8 It is the visual view of the planetary gear set of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention Figure 3 。

[0068] Figure 9 It is the structure diagram of the small sun gear of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0069] Figure 10 It is the structure diagram of the large sun gear of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0070] Figure 11 It is the structure diagram of the ring gear of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0071] Figure 12 It is the structure diagram of the planet carrier of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0072] Figure 13 It is the schematic diagram of the planetary gear set mechanism of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0073] Figure 14 It is the structure diagram of the planetary gear set with a lock of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0074] Figure 15 It is the structure diagram of the lock of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0075] Figure 16It is the structural diagram of the preferred solution of the lock of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention.

[0076] Figure 17 It is the schematic structural diagram of the lock cylinder of the lock of the active variable steering system implemented based on the planetary gear set mechanism described in the present invention. Specific embodiments

[0077] The following further elaborates on the present invention with reference to the accompanying drawings, so that those skilled in the art can implement it according to the text of the specification.

[0078] As Figures 1 to 17 shown, the present invention provides an active variable steering system implemented based on a planetary gear set mechanism, which realizes variable transmission ratios of the vehicle steering system at different vehicle speeds to meet the requirements of easy operation at low and medium speeds and handling stability at high speeds during vehicle driving. Its main structure includes a steering device, a double-row planetary gear set device, an output shaft, and a lock; among them, the steering device includes an input shaft 106 for inputting steering power, and the double-row planetary gear set device includes a small sun gear 204, a short planetary gear 206, a gear shaft 202a, a large sun gear 202, a long planetary gear 205, a planet carrier 201, a planet carrier 207, and a ring gear 203; among them, the small sun gear 204 is fixedly installed at one end of the input shaft 106, the gear shaft 202a is rotatably sleeved at the other end of the input shaft 106, the large sun gear 202 is fixedly installed at one end of the gear shaft 202a and is simultaneously rotatably sleeved on the input shaft 106, the short planetary gear 206 meshes and drives with the small sun gear 204, and the long planetary gear 205 simultaneously meshes and drives with the short planetary gear 206, the large sun gear 202, and the ring gear 203; the output shaft 108 is fixedly connected to the ring gear 203 for outputting the steering power; two locks 301, 302 are respectively sleeved on the outer sides of the planet carrier 201 and the other end of the gear shaft 202a for selectively locking the planet carrier 201 or the large sun gear 202 to stop rotating; the lock includes two relatively symmetrically arranged arc-shaped support plates 404, two relatively symmetrically arranged friction plates 403, a two-way lock cylinder 401, and a tensioning device; one ends of the two relatively symmetrically arranged arc-shaped support plates 404 are fixedly installed on the transmission gearbox 107 at the same time, the two relatively symmetrically arranged friction plates 403 are respectively fixedly installed on the inner sides of the arc-shaped support plates 404 in one-to-one correspondence, and the tensioning device is used to lock the planet carrier 207 or the large sun gear 202 by the tensioning action of the tensioning device in the initial working state; the two-way lock cylinder 401 is arranged between the other ends of the arc-shaped support plates 404, and the pistons 603 on both sides of the two-way lock cylinder 401 are respectively connected to the other ends of the arc-shaped support plates 404 at the same time;

[0079] In another embodiment, to achieve the above object, the present invention adopts the following technical solution. The structure specifically includes:

[0080] As Figure 1 shown, the active steering system is controlled to rotate by the steering wheel 101, driving the steering shaft 102 to rotate. The steering shaft 102 is connected to the outer end of the input shaft 106 in the support box 109 through a pair of cross-axis universal joints 104. A steering sleeve 103 is sleeved outside the steering shaft 102. The steering sleeve 103 is fixedly supported by a bracket assembly 105, and its position is adjustable.

[0081] As Figure 2 shown is a schematic structural diagram of the support box 109 fixed on the vehicle chassis for supporting the transmission gearbox 107. The support box 109 is a stepped cylindrical box body composed of an upper box cover and a lower box bottom. Its two ends are respectively supported on the input shaft 106 and the output shaft 108 through bearings, and the transmission gearbox 107 can rotate circumferentially around the input shaft 106 in the support box 109. Two oil filling holes corresponding to those on the box cover of the transmission gearbox 107 are provided on the box cover of the support box 109, and there is a corresponding oil pipeline connection between them and it is not affected by the rotation of the transmission gearbox 107. The oil volume in the bottom of the support box 109 changes with the vehicle speed. As the vehicle speed increases, its oil volume gradually increases, thereby increasing the friction force with the outer shell of the transmission gearbox 107. When the vehicle speed is low, preferably when the vehicle speed is lower than 40 km / h in the embodiment, the friction force can be ignored and the transmission gearbox 107 can rotate freely. When the vehicle speed exceeds the calibrated low-speed critical value, the oil friction force will restrict the free rotation of the transmission gearbox 107.

[0082] As Figures 3 to 5 shown, the transmission gearbox 107 is composed of a transmission gearbox bottom shell 107a, a transmission gearbox box cover 107b and its end covers encapsulated by bolts. Among them, the input shaft 106 and the output shaft 108 are respectively supported in the transmission gearbox 107 through bearings 110a and 110b. The inner end of the input shaft 106 and the inner end of the output shaft 108 are sleeved and connected through bearings in the transmission gearbox 107. The outer end of the output shaft 108 is connected to the input gear shaft in the steering gear 111. As a preference, in this embodiment, the steering gear 111 is preferably a rack and pinion type steering gear.

[0083] As Figures 6 to 12As shown, the small sun gear 204 is installed and fixed on one side of the input shaft 106 near the inner end. The gear shaft 202a is installed on the input shaft 106 on the left side of the small sun gear 204 through a needle roller bearing. The large sun gear 202 is installed and fixed at the right end of the gear shaft 202a, and there is a certain installation spacing between the small sun gear 204 and the large sun gear 202. The planet carrier 201 is installed on the gear shaft 202a through a needle roller bearing, and there is a certain installation spacing between the planet carrier 201 and the large sun gear 202. The planet carrier 207 is installed on the input shaft 106 on the right side of the small sun gear 204 through a needle roller bearing, and there is a certain installation spacing between the planet carrier 207 and the small sun gear 204. As a preference, in this embodiment, the installation spacing between the small sun gear 204 and the large sun gear 202 is about 3 mm to 5 mm, the installation spacing between the planet carrier 201 and the large sun gear 202 is about 2 mm, and the installation spacing between the planet carrier 207 and the small sun gear 204 is about 2 mm.

[0084] As Figure 8 shown, three short planet gears 206 are evenly distributed on the circumference of the small sun gear 204, and the short planet gears 206 are all meshed with the small sun gear 204, and their widths are the same as the width of the small sun gear 204. Three long planet gears 205 meshed with it are evenly distributed on the circumference of the large sun gear 202. The left end of their installation position is aligned with the left end face of the large sun gear 202, and the right end is aligned with the right end face of the small sun gear 204. The right end teeth of the long planet gears 205 are all meshed with the short planet gears 206. As a preference, in this embodiment, the sum of the circumferential radius of the small sun gear 204 and the circumferential diameter of the short planet gear 206 is equal to the circumferential radius of the large sun gear 202, and the circumferential diameter of the long planet gear 205 is equal to the circumferential diameter of the short planet gear 206.

[0085] The long planet gear 205 and the short planet gear 206 are respectively installed and supported between the planet carrier 201 and the planet carrier 207 through pins 205a and 206a, and the planet gears can rotate freely around the pins, but both ends of the pin 205a are fixed on the two-side planet carriers 201 and 207, while the right end of the pin 206a is fixed on the planet carrier 207.

[0086] The axial installation position of the ring gear 203 overlaps with the installation position of the small sun gear 204. The internal gear ring of the ring gear 203 is simultaneously meshed with the three long planet gears 205, and the width of the ring gear 203 is not greater than the width of the small sun gear 204. The large end of the ring gear output bracket 203a is fixed on the right end face of the ring gear 203, and the small end is connected and fixed to the output shaft 108, and its structural shape does not cause movement interference with the planet carrier 207.

[0087] As Figure 13As shown in the figure, the planetary gear mechanism is composed of a two-row planetary gear set mechanism. There are two rows of meshing planetary gears between the small sun gear 204 and the ring gear 203. The front row is a single planetary gear mechanism where the long planetary gear 205 meshes with the large sun gear 202, and the rear row is a double planetary gear mechanism where the long planetary gear 205 meshes with the short planetary gear 206, as well as the small sun gear 204 and the ring gear 203.

[0088] According to the operating characteristics of the planetary gear set mechanism, when any component in the planetary gear set is fixed, the other components can rotate relative to it; when any two components in the planetary gear set are fixed, the entire planetary gear set can rotate simultaneously as a whole mechanism. Therefore, the motion constraint relationship of this two-row planetary gear set mechanism needs to satisfy the following motion equations:

[0089]

[0090] Among them, n 202 is the rotational speed of the large sun gear, n 203 is the rotational speed of the ring gear, n 201 is the rotational speed of the planet carrier, n 204 is the rotational speed of the small sun gear. α1 and α2 are the mechanism parameters of the front and rear row planetary gear sets respectively, and satisfy the relationship:

[0091]

[0092] In the formula, z 202 is the number of teeth of the second sun gear, z 203 is the number of teeth of the ring gear, z 204 is the number of teeth of the first sun gear.

[0093] Therefore, on the premise that the small sun gear 204 connected to the input shaft 106 is the input component and the ring gear 203 connected to the output shaft 108 is the output component, different transmission speed change relationship requirements can be achieved by fixing and constraining certain components in this two-row planetary gear set. By changing the motion relationship of the planetary gears in the transmission gearbox 107, the angular relationship change between the input shaft 106 and the output shaft 108 can be changed (i.e., the transmission ratio change of the transmission gearbox 107), and the addition of the transmission gearbox 107 does not affect the reversible effect of the original steering system.

[0094] Such as Figure 14 、 15 As shown in the figure, the sun gear lock 301 and the planet carrier lock 302 are respectively installed on the gear shaft 202a and the planet carrier 201. The bottoms of the two locks are respectively supported by the support pins 405 on the sun gear lock base 301a and the planet carrier lock base 302a in the bottom case 107a of the transmission gearbox.

[0095] The bottom ends of the arc-shaped support plates 404 in the two locking devices are connected to the locking device base through support pins 405 and can swing around the support pins 405. The top ends of the two side support plates 404 are constraint-connected through a tension spring 402 and a locking device oil cylinder 401. The friction plates 403 are fixedly installed on the inner sides of the support plates 404, and the inner and outer arc shapes thereof respectively match the outer circle of the corresponding locking component and the inner shape of the support plates 404. The minimum inner ring radius of the support plates 404 is greater than the inner ring radius of the friction plates 403 to prevent movement interference between the support plates 404 and the locking components; the friction plates 403 are made of wear-resistant materials with good thermal conductivity.

[0096] As shown in Figure 14 , in the initial working position, due to the tension of the tension spring 402 at the top ends of the support plates 404, the two side support plates 404 of the locking device lock the gear shaft 202a and the planet carrier 201 completely through the friction plates 403.

[0097] In another embodiment, as shown in Figure 16 , the two side support plates 404 and the friction plates 403 of the two locking devices lock the gear shaft 202a and the planet carrier 201 through a tension device 501. The tension device 501 is composed of a composite of a spiral spring and a shock absorber. The inner end of the tension device 501 is fixed to the outer side of the upper end of the support plate 404, and the outer end is fixed to the inner wall of the transmission gearbox cover 107b through a support 502. The tension device 501 can automatically adjust the pre-tightening degree of the locking device as the friction plates 403 wear, preventing the two locking devices from slipping.

[0098] As shown in Figure 4 、 5 , the sun gear locking device oil injection hole 301b and the planet carrier locking device oil injection hole 302b on the transmission gearbox cover 107b are respectively connected to the locking device oil cylinders 401 on the sun gear locking device 301 and the planet carrier locking device 302.

[0099] As shown in Figure 17 , the locking device oil cylinder 401 is a two-way piston oil cylinder structure encapsulated by a cylinder block 601 and a protective cover 606. There is a spiral spring 605 in the oil chamber corresponding to the oil port 401a of the locking device oil cylinder. The two ends of the spiral spring 605 are connected to sealing gaskets 604 to seal the oil in the oil chamber. The outer sides of the two sealing gaskets 604 are respectively connected to the inner sides of the two end pistons 603. The two end pistons 603 are in close contact with the top ends of the two side support plates 404 through top blocks 602.

[0100] When the vehicle control unit controls the oil to be injected into the lock cylinder 401a of the lock through the oil port, the oil in the cylinder block 601 pushes the pistons 603 at both ends outward through the gasket 604, prompting the top block 602 to push the tops of the two side support plates 404 outward to expand around the support pins 405 until the friction plate 403 is completely separated from the gear shaft 202a or the planet carrier 201, and the oil pressure in the lock cylinder 401 is kept in balance with the acting force of the tension spring 402. At this time, the tension spring 402 is stretched, and the protective covers 606 on both sides are compressed.

[0101] When the vehicle control unit controls the oil in the lock cylinder 401 to flow back to the fuel tank, under the tension of the tension spring 402 and the self-acting forces of the spiral spring 605 and the protective covers 606, the two side support plates 404 of the lock quickly and smoothly re-lock the gear shaft 202a or the planet carrier 201 through the friction plate 403.

[0102] When the double-row planetary gear set mechanism is in the initial working position, the sun gear lock 301 and the planet carrier lock 302 lock the large sun gear 202 and the planet carrier 201 simultaneously due to the tension of the tension spring 402 (or the tension device 501). At this time, the entire planetary gear set can only rotate synchronously as a whole mechanism;

[0103] At this time, when the input shaft 106 is rotated, the small sun gear 204 drives the entire planetary gear set to rotate synchronously with the input shaft 106, that is, the output shaft 108 and the input shaft 106 rotate at the same speed. At this time, the transmission ratio of the transmission gearbox 107 is 1, which does not affect the steering transmission ratio of the original steering system.

[0104] The working process of an active variable steering system based on a planetary gear set mechanism provided by the present invention includes:

[0105] When the vehicle control unit controls the oil to be injected from the fuel tank into the lock cylinder 401 on the planet carrier lock 302 through the oil injection hole 302b of the planet carrier lock until the planet carrier lock 302 is completely separated from the planet carrier 201, the planet carrier 201 can rotate freely, but at this time the large sun gear 202 is still locked, and the small sun gear 204 can drive and rotate with each other through the planet gears with the planet carrier 201 and the ring gear 203.

[0106] At this time, when the input shaft 106 rotates, the small sun gear 204 drives the short planet gear 206 to rotate in the reverse direction around the pin 206a along with the input shaft 106, and the short planet gear 206 then drives the long planet gear 205 to rotate in the reverse direction around the pin 205a. Since the planet carriers 201 and 207 rotate in the same direction around the small sun gear 204 along with the planet gears, furthermore, the long planet gear 205 drives the ring gear 203 and the ring gear output bracket 203a to rotate in the same direction as the small sun gear 204 together, and then the output shaft 108 drives the steering gear 111.

[0107] Since the large sun gear 202 is fixed, that is, n 202 = 0, substituting it into the motion equation of the double-row planetary gear set mechanism, we get:

[0108]

[0109] At this time, the transmission ratio achieved by this double-row planetary gear set mechanism is And Therefore, the transmission gearbox 107 amplifies the steering transmission ratio of the original steering system.

[0110] When the vehicle control unit controls the oil to be injected from the fuel tank into the locking cylinder 401 on the sun gear lock 301 through the oil injection hole 301b of the sun gear lock until the sun gear lock 301 is completely separated from the gear shaft 202a, the large sun gear 202 can rotate freely, but at this time the planet carrier 201 is still in the locked state, and the small sun gear 204 can drive and rotate with each other between the large sun gear 202 and the ring gear 203 through the planet gears;

[0111] At this time, when the input shaft 106 rotates, the small sun gear 204 drives the short planet gear 206 to rotate in the reverse direction around the pin 206a along with the input shaft 106, and the short planet gear 206 then drives the long planet gear 205 to rotate in the reverse direction around the pin 205a. Since the planet carrier 201 is in the locked state and the planet carrier 207 is also stationary along with the pin 205a, therefore, the inner ring of the long planet gear 205 drives the large sun gear 202 to rotate in the reverse direction, and the outer ring drives the ring gear 203 and the ring gear output bracket 203a to rotate in the same direction as the small sun gear 204 together, and then the output shaft 108 drives the steering gear 111.

[0112] Since the planet carrier 201 is fixed, that is, n 201 = 0, substituting it into the motion equation of the double-row planetary gear set mechanism, we get:

[0113]

[0114] At this time, the transmission ratio achieved by this double-row planetary gear set mechanism is And α2 > 1;

[0115] Also, because,

[0116] At this time, the double-row planetary gear set mechanism achieves a relatively large transmission ratio, so the transmission gearbox 107 relatively amplifies the steering transmission ratio of the original steering system to a greater extent.

[0117] During actual vehicle driving, the vehicle control unit will timely control the change of the transmission ratio of the transmission gearbox 107 according to the vehicle speed change to achieve the precise matching of the steering transmission ratio and the vehicle speed, so as to ensure the handling convenience at low vehicle speeds and the handling stability at high vehicle speeds. Therefore, the transmission ratio i of the transmission gearbox 107 corresponding to the vehicle speed change range satisfies the following transmission ratio relationship:

[0118]

[0119] In the formula, umin and umax are the upper and lower critical vehicle speed values during vehicle driving.

[0120] At the same time, to ensure the stability requirement during vehicle steering and always keep the yaw rate gain during vehicle steering within a stable range, which is beneficial to improving the lateral stability of the vehicle and also helps the driver reduce the compensation correction for the change of vehicle steering characteristics. The ideal transmission ratio i of the original vehicle steering system sw should also satisfy the following relationship:

[0121]

[0122] In the formula, G sw is the expected yaw rate gain, u is the vehicle speed, L is the wheelbase, and K is the vehicle stability factor.

[0123] Therefore, to ensure a stable expected yaw rate gain of the vehicle, the transmission ratio i of the transmission gearbox 107 in the active steering system should also satisfy the relationship:

[0124]

[0125] Also, because i sw = δ s δ f ;

[0126] So,

[0127] In the formula, δ s is the steering wheel input angle, and δ f is the steering wheel angle.

[0128] To ensure that the values of α2 and meet the best expected yaw rate gain for vehicle stability.

[0129] To ensure the handling stability requirements during vehicle steering, 40 km / h and 60 km / h are preferably selected as the upper and lower critical vehicle speeds for the intermediate vehicle speed, to meet the limited requirements of the driving conditions and road conditions of most vehicles. That is, the transmission ratio i of the transmission gearbox 107 is based on the transmission ratio relationship corresponding to the specific vehicle speed change range as follows:

[0130]

[0131] The present invention also provides an active variable steering method implemented based on a planetary gear set mechanism, including:

[0132] When the vehicle is driving in the starting or low-speed range, the steering wheel angle input of the steering wheel 101 is transmitted to the steering gear 111 through the steering shaft 102, universal joint 104, input shaft 106, transmission gearbox 107, and output shaft 108. At this time, the transmission gearbox 107 is in the initial working state, the sun gear lock 301 and the planet carrier lock 302 are in a completely locked state, the large sun gear 202 and the planet carrier 201 are simultaneously locked. When the input shaft 106 is rotated, the small sun gear 204 drives the entire planetary gear set to rotate synchronously with the input shaft 106, that is, the output shaft 108 and the input shaft 106 rotate at the same speed. Therefore, a direct steering transmission ratio can be achieved to ensure the steering lightness and comfort requirements of the original steering system.

[0133] When the vehicle travels in the medium-speed range interval, the vehicle control unit controls the oil to be injected into the lock cylinder 401 of the planet carrier lock 302 until the planet carrier 201 is completely separated from the planet carrier lock 302, while the large sun gear 202 remains in the locked state. When the input shaft 106 rotates with the steering wheel 101, the small sun gear 204, as the driving part, drives the long planet gear 205 and the short planet gear 206 to rotate synchronously with the planet carrier 201, and then drives the ring gear 203 and the ring gear output frame 203a to rotate in the same direction as the small sun gear 204. Then, the output shaft 108 drives the steering gear 111 to work. At this time, the medium-speed gear steering transmission ratio is achieved, and the same steering wheel angle input corresponds to a relatively smaller steering wheel steering angle to meet the steering handling lightness and stability requirements during vehicle driving.

[0134] When the vehicle travels in the high-speed range or above, the vehicle control unit controls the oil to be injected into the locking cylinder 401 on the sun gear lock 301 until the gear shaft 202a is completely separated from the sun gear lock 301. At the same time, the oil in the locking cylinder 401 on the planet carrier lock 302 is quickly returned to the fuel tank through the vehicle control unit, so that the planet carrier 201 returns to the fully locked state. When the input shaft 106 rotates with the steering wheel 101, the small sun gear 204 drives the short planet gear 206 and the long planet gear 205 to rotate around the pin as the driving part. The long planet gear 205 drives the ring gear 203 and the ring gear output bracket 203a to rotate in the same direction as the small sun gear 204. Then, the output shaft 108 drives the steering gear 111 to work. At this time, the high-speed steering transmission ratio is realized, and the same steering wheel angle input corresponds to the minimum steering wheel steering angle to meet the steering control stability requirements of vehicle driving.

[0135] Conversely, when the vehicle travels from high speed to medium speed, the vehicle control unit controls the oil to be injected into the locking cylinder 401 on the planet carrier lock 302 through the oil injection hole 302b of the planet carrier lock until the planet carrier 201 is completely separated from the planet carrier lock 302. At the same time, the oil in the locking cylinder 401 on the sun gear lock 301 is quickly returned to the fuel tank through the vehicle control unit, so that the gear shaft 202a returns to the fully locked state. At this time, the transmission gearbox 107 realizes the steering transmission ratio of the medium speed gear again to meet the steering control lightness and stability requirements of vehicle driving.

[0136] When the vehicle travels from medium speed to low speed, the vehicle control unit controls the oil in the locking cylinder 401 on the planet carrier lock 302 to be quickly returned to the fuel tank through the vehicle control unit, so that the planet carrier 201 returns to the initial locked state. At this time, the transmission gearbox 107 realizes the initial direct gear transmission ratio again to meet the steering lightness and comfort requirements of vehicle driving.

[0137] The vehicle control unit will, according to the real-time vehicle speed, engine output and other parameters detected by different sensors, timely control the locked or separated state of the sun gear lock 301 or the planet carrier lock 302 through the vehicle speed change and driving requirements, and then change the transmission relationship of the planetary gear set in the transmission gearbox 107 to realize different transmission ratio requirements and meet the steering transmission ratio requirements at different vehicle speeds.

[0138] In another embodiment, according to the situation that the vehicle speed changes quickly and the vehicle speed range is maintained for a short time during vehicle driving, the transmission ratio change of the transmission gearbox 107 can be controlled by the vehicle control unit to change from the direct gear to the high-speed gear, or from the high-speed gear to the direct gear, but ensure that the input gear of the steering gear 111 is in the initial central position before switching the transmission ratio of the transmission gearbox 107.

[0139] When the vehicle suddenly accelerates from low speed to high speed range during driving, the vehicle control unit controls the oil to be injected into the locking cylinder 401 on the sun gear lock 301 until the gear shaft 202a is completely separated from the sun gear lock 301. At this time, the planet carrier 201 is still kept in the initial locked state by the planet carrier lock 302. When the input shaft 106 rotates with the steering wheel 101, the small sun gear 204 drives the short planet gear 206 and the long planet gear 205 to rotate around the pin as the driving part. The long planet gear 205 drives the ring gear 203 to rotate in the same direction as the small sun gear 204, and then the output shaft 108 drives the steering gear 111 to work. At this time, the transmission gearbox 107 directly shifts gears to achieve the high-speed steering transmission ratio;

[0140] Conversely, when the vehicle suddenly decelerates from high speed to low speed range during emergency braking during driving, the vehicle control unit controls the oil to quickly flow back from the locking cylinder 401 on the sun gear lock 301 to the fuel tank, so that the gear shaft 202a and the large sun gear 202 return to the initial locked state. At this time, the transmission gearbox 107 directly shifts gears to achieve the direct gear steering transmission ratio.

[0141] As a preference, in this embodiment, the low speed range is 0 < u < 40 km / h, the medium speed range is 40 km / h ≤ u ≤ 60 km / h, and the high speed range is u > 60 km / h.

[0142] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples here.

Claims

1. An active variable steering system implemented based on a planetary gear set mechanism, characterized in that, Comprising: A steering device, which includes an input shaft for inputting steering power; A double-row planetary gear set device, which includes a first sun gear, a first planet gear, a gear shaft, a second sun gear, a second planet gear, a planet carrier and a ring gear; Wherein, the first sun gear is fixedly installed at one end of the input shaft; the gear shaft is rotatably sleeved at the other end of the input shaft; the second sun gear is fixedly installed at one end of the gear shaft and is simultaneously rotatably sleeved on the input shaft; both ends of the planet carrier are respectively rotatably sleeved on the gear shaft and one end of the input shaft; the first planet gear and the second planet gear are rotatably sleeved on the planet carrier; the first planet gear meshes and drives with the first sun gear, and the second planet gear simultaneously meshes and drives with the first planet gear, the second sun gear and the ring gear; there is an installation spacing of about 3 mm to 5 mm between the first sun gear and the second sun gear; An output shaft, which is fixedly connected to the ring gear and is used for outputting the steering power; Two locking devices, which are respectively sleeved on the outer side of the planet carrier and the outer side of the other end of the gear shaft, and are used for selectively locking the planet carrier or the second sun gear to stop rotating; Wherein, the locking device includes: Two relatively symmetrically arranged arc-shaped support plates, one end of which is simultaneously fixedly installed on the transmission gearbox; Two relatively symmetrically arranged friction plates, which are respectively fixedly installed on the inner sides of the arc-shaped support plates in one-to-one correspondence; Wherein, the inner and outer arc shapes of the friction plate respectively match the outer circle of the corresponding locking component and the shape of the inner side of the support plate, and the minimum inner ring radius of the support plate is greater than the inner ring radius of the friction plate; A tensioning device, which is used for, in the initial working state, locking the planet carrier or the second sun gear by the tensioning action of the tensioning device; A two-way locking cylinder, which is arranged between the other ends of the arc-shaped support plates, and the pistons on both sides inside the two-way locking cylinder are respectively simultaneously connected to the other ends of the arc-shaped support plates.

2. The active variable steering system implemented based on the planetary gear set mechanism according to claim 1, characterized in that, Further comprising: A support pin, which is fixedly installed on the transmission gearbox; Wherein, one end of the arc-shaped support plate is simultaneously fixedly installed on the transmission gearbox through the support pin, and one end of the arc-shaped support plate can rotate around the support pin; and A support box, which is fixedly installed on the vehicle chassis; Wherein, the input shaft and the output shaft are rotatably supported on the covers at both ends of the support box.

3. The active variable steering system implemented based on the planetary gear set mechanism according to claim 2, characterized in that, The tensioning device is a tensioning spring, and both ends of which are simultaneously connected to the other end of the arc-shaped support plate.

4. The active variable steering system implemented based on the planetary gear set mechanism according to claim 2, wherein The tensioning device includes: Two first helical springs, one end of each of which respectively abuts against the other end of the arc-shaped support plate in one-to-one correspondence; Two supports, which are respectively arranged corresponding to the two helical springs, the supports are fixedly installed on the transmission gearbox, and the other ends of the helical springs are respectively fixedly connected to the supports in one-to-one correspondence.

5. The active variable steering system implemented based on the planetary gear set mechanism according to claim 3 or 4, characterized in that The planet carrier includes: A first planet support; A second planet support, which is arranged opposite to the first planet support; The first planetary gear pin, one end of which is fixedly connected to the first planetary carrier, and the first planetary gear can rotate around the first planetary gear pin; The second planetary gear pin, both ends of which are fixedly connected to the first planetary carrier and the second planetary carrier respectively, and the second planetary gear can rotate around the second planetary gear pin; Wherein, the lock is sleeved outside the second planetary carrier; there is an installation spacing of about 2 mm between the second planetary carrier and the second sun gear, and between the first planetary carrier and the first sun gear.

6. The active variable steering system implemented based on the planetary gear set mechanism according to claim 5, characterized in that, The two-way locking cylinder includes: A cylinder block; A protective cover, which forms a sealed oil chamber with the cylinder block; A second helical spring, which is arranged in the sealed oil chamber; Two sealing gaskets, which are symmetrically arranged on both sides of the second helical spring, one side of the sealing gasket is respectively connected to both ends of the second helical spring, and the other side is connected to one side of the piston; Two top blocks, one side of which is connected to the other side of the piston, and the other side is respectively connected to the arc-shaped support plate.

7. An active steering method with variable steering ratio implemented based on a planetary gear set mechanism, characterized in that, Using the active variable steering system implemented based on the planetary gear set mechanism as described in any one of claims 1-6, including: When the vehicle is starting or traveling at a low speed, the transmission gearbox is in an initial working state, so that the locks are all in a locked state. At this time, the planetary carrier and the second sun gear are both in a locked state; When the vehicle is traveling at a medium speed, oil is injected into the locking cylinder on the planetary carrier until the planetary carrier and the lock on the planetary carrier are completely separated. At the same time, the oil in the locking cylinder on the second sun gear flows back to the fuel tank. At this time, the second sun gear is in a locked state; When the vehicle is traveling at a high speed, oil is injected into the locking cylinder on the second sun gear until the second sun gear and the lock on the second sun gear are completely separated. At the same time, the oil in the locking cylinder on the planetary carrier flows back to the fuel tank. At this time, the planetary carrier is in a locked state.

8. The active steering method with variable steering ratio implemented based on the planetary gear set mechanism according to claim 7, characterized in that, It further includes: When the vehicle travels from a low speed to a medium speed, oil is injected into the locking cylinder on the planetary carrier until the planetary carrier and the lock on the planetary carrier are completely separated. At this time, the second sun gear is in a locked state; When the vehicle travels from a medium speed to a high speed, oil is injected into the locking cylinder on the second sun gear until the second sun gear and the lock on the second sun gear are completely separated. At the same time, the oil in the locking cylinder on the planetary carrier flows back to the fuel tank. At this time, the planetary carrier is in a locked state; When the vehicle travels from a high speed to a medium speed, oil is injected into the locking cylinder on the planetary carrier until the planetary carrier and the lock on the planetary carrier are completely separated. At the same time, the oil in the locking cylinder on the second sun gear flows back to the fuel tank. At this time, the second sun gear is in a locked state; When the vehicle travels from a medium speed to a low speed, the oil in the locking cylinder on the planetary carrier flows back to the fuel tank. At this time, the planetary carrier and the second sun gear are both in a locked state.

9. The active steering method with variable steering ratio implemented based on the planetary gear set mechanism according to claim 7, characterized in that, It further includes: When the vehicle travels from a low speed to a high speed, oil is injected into the locking cylinder on the second sun gear until the second sun gear and the lock on the second sun gear are completely separated. At this time, the planetary carrier is in a locked state; When the vehicle travels from high speed to low speed, the oil in the locking cylinder on the second sun gear flows back into the oil storage tank. At this time, the planet carrier and the second sun gear are both in a locked state.

10. The active steering method with variable steering ratio implemented based on the planetary gear set mechanism as claimed in claim 8 or 9, characterized in that, The constraint relationship of the double-row planetary gear set device satisfies: Among them, where n 202 is the rotational speed of the second sun gear, n 203 is the rotational speed of the ring gear, n 201 is the rotational speed of the planet carrier, n 204 is the rotational speed of the first sun gear, z 202 is the number of teeth of the second sun gear, z 203 is the number of teeth of the ring gear, z 204 is the number of teeth of the first sun gear; and The transmission ratio i of the transmission gearbox is based on the transmission ratio relationship corresponding to the vehicle speed change range as where u is the vehicle speed, and umin and umax are the upper and lower critical vehicle speed values of the intermediate vehicle speed during vehicle travel.

Images