阅读说明：本技术 一种柔性随重心高度自适应调节的车辆悬架 (Vehicle suspension with flexibility adaptively adjusted along with gravity height ) 是由 班书昊 李晓艳 谭邹卿 于 2021-11-15 设计创作，主要内容包括：本发明公开了一种柔性随重心高度自适应调节的车辆悬架,属于车辆悬架技术领域。它包括与车架相连的车架连接板,与车桥相连的车桥连接板,装设在车架连接板和车桥连接板之间的阻尼连接板,还包括变柔度单元和柔度控制单元；变柔度单元,转动装设在阻尼连接板上,上端滑动且转动装设在车架连接板上,下端滚动装设在车桥连接板上,用于改变车架与车桥之间的柔性以适应车辆重心高度的变化；柔度控制单元,滑动装设在车架连接板上,驱动变柔度单元的柔度突跳。本发明是一种结构合理、在车辆在行驶过程中能够主动改变车辆重心高度,并自适应调节悬架柔性增加行驶稳定性的车辆悬架。(The invention discloses a vehicle suspension with flexibility adaptively adjusted along with the height of a gravity center, and belongs to the technical field of vehicle suspensions. The device comprises a frame connecting plate connected with a frame, an axle connecting plate connected with an axle, a damping connecting plate arranged between the frame connecting plate and the axle connecting plate, a flexibility changing unit and a flexibility control unit; the flexibility changing unit is rotatably arranged on the damping connecting plate, the upper end of the flexibility changing unit slides and is rotatably arranged on the frame connecting plate, and the lower end of the flexibility changing unit is rotatably arranged on the axle connecting plate and is used for changing the flexibility between the frame and the axle to adapt to the change of the gravity center height of the vehicle; and the flexibility control unit is arranged on the frame connecting plate in a sliding manner and drives the flexibility kick of the flexibility changing unit. The vehicle suspension is reasonable in structure, can actively change the height of the gravity center of the vehicle in the running process of the vehicle, and adaptively adjusts the flexibility of the suspension to increase the running stability.)

1. The utility model provides a vehicle suspension of flexibility along with height of center of gravity self-adaptation regulation, includes the vehicle frame connecting plate (11) that links to each other with the frame, axle connecting plate (13) that links to each other with the axle, installs damping connecting plate (12) between vehicle frame connecting plate (11) and axle connecting plate (13), its characterized in that: also comprises

The flexibility changing unit is rotatably arranged on the damping connecting plate (12), the upper end of the flexibility changing unit is slidably and rotatably arranged on the frame connecting plate (11), and the lower end of the flexibility changing unit is rotatably arranged on the axle connecting plate (13) and is used for changing the flexibility between the frame and the axle to adapt to the change of the gravity center height of the vehicle;

and the flexibility control unit is arranged on the frame connecting plate (11) in a sliding manner and drives the flexibility kick of the flexibility changing unit.

2. The vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity as claimed in claim 1, wherein: a damping unit for absorbing vibration energy in the vertical direction is also arranged between the damping connecting plate (12) and the axle connecting plate (13); the damping unit comprises a hydraulic cylinder A (51) and a hydraulic cylinder B (52) which are arranged in parallel along the vertical direction; the cylinder body of the hydraulic cylinder A (51) and the cylinder body of the hydraulic cylinder B (52) are connected with the axle connecting plate (13), and the output rod of the hydraulic cylinder A (51) and the output rod of the hydraulic cylinder B (52) are connected with the damping connecting plate (12).

3. The vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity as claimed in claim 1, wherein: the variable flexibility unit comprises a variable flexibility unit A (2) and a variable flexibility unit B (3) which are crossly and rotatably arranged on the damping connecting plate (12); the flexibility changing unit A (2) and the flexibility changing unit B (3) respectively comprise a sliding block (26) which is arranged on the frame connecting plate (11) in a sliding way along the horizontal direction, the upper end of the flexibility changing unit A (2) is connected with the sliding block (26) in a rotating way, the middle part of the upper end of the flexibility changing unit A (2) is connected with the damping connecting plate (12) by a pin shaft (121) and a connecting rod (21) which is arranged obliquely, a one-way compound gear (22) which is arranged on the connecting rod (21) and is meshed with the flexibility control unit is rotated, a rigidity switching component (23) which is arranged on the connecting rod (21) and is positioned below the pin shaft (121) is rotated, a transmission chain (24) which is connected with the one-way compound gear (22) and the rigidity switching component (23) is rotated and is arranged on a roller (25) at the lower end of the connecting rod (21) in the flexibility changing unit A (2) and a spring A (27) which is connected with the lower end of the connecting rod (21) in the flexibility changing unit B (3) at both ends, a spring B (28) with two ends respectively connected with the rigidity switching component (23) in the flexibility changing unit A (2) and the connecting rod (21) in the flexibility changing unit B (3), and a spring C (29) with two ends respectively connected with the connecting rod (21) in the flexibility changing unit A (2) and the rigidity switching component (23) in the flexibility changing unit B (3); the roller (25) is connected with the axle connecting plate (13) in a rolling mode, and in an initial state, the spring A (27), the spring B (28) and the spring C (29) are parallel to each other.

4. A vehicle suspension having a flexibility that is adaptively adjustable with respect to the height of the center of gravity as set forth in claim 3, wherein: when the distance between the frame connecting plate (11) and the axle connecting plate (13) is in a first distance range, the spring A (27) is in an operating state, and the spring B (28) and the spring C (29) are in a non-operating state; when the distance between the frame connecting plate (11) and the axle connecting plate (13) is in a second distance range, the spring A (27) and the spring B (28) are in an operating state, and the spring C (29) is in a non-operating state; when the distance between the frame connecting plate (11) and the axle connecting plate (13) is within a third distance range, the spring A (27), the spring B (28) and the spring C (29) are in working states; wherein the first distance is greater than the second distance, and the second distance is greater than the third distance.

5. The vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity as claimed in claim 4, wherein: the rigidity switching assembly (23) comprises a gear C (231) rotatably arranged on the connecting rod (21), a spring pin sliding groove (232) arranged on the gear C (231) along the diameter direction, and a spring pin (233) arranged in the spring pin sliding groove (232) in a sliding manner; and the spring pin (233) in the variable flexibility unit A (2) is connected with the left end of the spring B (28), and the spring pin (233) in the variable flexibility unit B (3) is connected with the right end of the spring C (29).

6. The vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity as claimed in claim 4, wherein: the flexibility control unit comprises a rack A (41) and a rack B (42) which are arranged on the frame connecting plate (11) in a sliding mode along the horizontal direction and can be far away from or close to each other, and a spring D (43) which is arranged between the rack A (41) and the rack B (42) and is always in a compressed state;

the one-way compound gear (22) comprises a rotating shaft (224) rotatably arranged on the connecting rod (21), a gear A (221) fixedly arranged on the rotating shaft (224), and a gear B (223) arranged on the rotating shaft (224) by adopting a one-way bearing (222); a gear A (221) in the variable flexibility unit A (2) is in meshing transmission with a rack A (41), and a gear A (221) in the variable flexibility unit B (3) is in meshing transmission with a rack B (42); the gear B (223) and the gear C (231) in the variable flexibility unit A (2) are connected by the transmission chain (24), and the gear B (223) and the gear C (231) in the variable flexibility unit B (3) are connected by the transmission chain (24); when the frame connecting plate (11) moves towards the axle connecting plate (13), the one-way bearing (222) is in a stop state, and when the frame connecting plate (11) moves away from the axle connecting plate (13), the one-way bearing (222) is in a start state.

7. The vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity as claimed in claim 4, wherein: the distance between the frame connecting plate (11) and the axle connecting plate (13) is positionedIn the first distance range, the included angle between the spring pin sliding groove (232) and the horizontal direction is not more thanThe deformation of the spring B (28) and the spring C (29) is zero; when the distance between the frame connecting plate (11) and the axle connecting plate (13) is within a second distance range, the included angle between the spring pin sliding groove (232) in the variable flexibility unit A (2) and the vertical direction is not more thanThe included angle between the spring pin sliding groove (232) in the variable flexibility unit B (3) and the horizontal direction is not more thanThe deformation of the spring C (29) is zero; when the distance between the frame connecting plate (11) and the axle connecting plate (13) is within a third distance range, the included angle between the spring pin sliding groove (232) and the vertical direction is not more than。

8. A vehicle suspension having a flexibility that is adaptively adjustable with respect to the height of the center of gravity as set forth in claim 3, wherein: an involute chute A (131) and an involute chute B (132) which are symmetrical relative to the flexibility control unit are formed in the vertical plane of the axle connecting plate (13), and a roller (25) in the variable flexibility unit A (2) and a roller (25) in the variable flexibility unit B (3) are respectively positioned in the involute chute A (131) and the involute chute B (132); when the two rollers (25) roll downwards along the axle connecting plate (13), the horizontal distance between the two rollers is increased, and the distance between the frame connecting plate (11) and the axle connecting plate (13) is reduced.

Technical Field

The invention mainly relates to the technical field of vehicle suspensions, in particular to a vehicle suspension with flexibility adaptively adjusted along with the height of a gravity center.

Background

The suspension is an important component connecting the vehicle frame and the vehicle axle and can absorb impact force from the ground. The suspension in the prior art mostly adopts a plate spring with constant rigidity, so that only one dynamic balance point is arranged in the driving process of a vehicle, the gravity center of the vehicle can be changed in a reciprocating manner only near one balance point, and the vehicle can drive on the same road surface at a high speed and a low speed with great comfort. In addition, when the vehicle passes over a rough road surface, the vehicle vibrates severely even when traveling at low speed because the dynamic balance center of gravity position of the vehicle does not change. Therefore, the design of the vehicle suspension with multi-balance point flexibility has important application value.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: aiming at the technical problems in the prior art, the invention provides the vehicle suspension which is reasonable in structure, can actively change the height of the gravity center of the vehicle in the running process of the vehicle, adaptively adjusts the flexibility of the suspension to increase the running stability, and adaptively adjusts the flexibility of the suspension along with the height of the gravity center.

In order to solve the problems, the solution proposed by the invention is as follows: the vehicle suspension with the flexibility adaptively adjusted along with the height of the center of gravity comprises a frame connecting plate connected with a vehicle frame, an axle connecting plate connected with an axle, a damping connecting plate arranged between the frame connecting plate and the axle connecting plate, and further comprises a flexibility changing unit and a flexibility control unit.

And the flexibility changing unit is rotatably arranged on the damping connecting plate, the upper end of the flexibility changing unit slides and is rotatably arranged on the frame connecting plate, and the lower end of the flexibility changing unit rolls on the axle connecting plate and is used for changing the flexibility between the frame and the axle to adapt to the change of the gravity center height of the vehicle.

And the flexibility control unit is arranged on the frame connecting plate in a sliding manner and drives the flexibility kick of the variable flexibility unit.

Furthermore, a damping unit for absorbing vibration energy in the vertical direction is also arranged between the damping connecting plate and the axle connecting plate; the damping unit comprises a hydraulic cylinder A and a hydraulic cylinder B which are arranged in parallel along the vertical direction; the cylinder body of the hydraulic cylinder A and the cylinder body of the hydraulic cylinder B are connected with the axle connecting plate, and the output rod of the hydraulic cylinder A and the output rod of the hydraulic cylinder B are connected with the damping connecting plate.

Further, the variable flexibility unit comprises a variable flexibility unit A and a variable flexibility unit B which are crossly and rotatably arranged on the damping connecting plate; the flexibility changing unit A and the flexibility changing unit B respectively comprise a sliding block which is arranged on the frame connecting plate in a sliding mode along the horizontal direction, a connecting rod, a one-way compound gear, a rigidity switching assembly, a transmission chain, a roller wheel, a spring A, a spring B and a spring C, wherein the upper end of the connecting rod is connected with the sliding block in a rotating mode, the middle of the connecting rod is connected with the damping connecting plate in a rotating mode through a pin shaft, the connecting rod is arranged on the connecting rod in an inclined mode, the one-way compound gear is meshed with the flexibility control unit in a rotating mode, the rigidity switching assembly is arranged on the connecting rod and is positioned below the pin shaft, the transmission chain is connected with the one-way compound gear and the rigidity switching assembly, the roller wheel is arranged at the lower end of the connecting rod, the two ends of the spring A are respectively connected with the lower end of the connecting rod in the flexibility changing unit A and the lower end of the connecting rod in the flexibility changing unit B, the two ends of the spring C are respectively connected with the connecting rod in the flexibility changing unit A and the rigidity switching assembly in the flexibility changing unit B; the roller is connected with the axle connecting plate in a rolling mode, and in an initial state, the spring A, the spring B and the spring C are parallel to each other.

Further, when the distance between the frame connecting plate and the axle connecting plate is within a first distance range, the spring A is in a working state, and the spring B and the spring C are in a non-working state; when the distance between the frame connecting plate and the axle connecting plate is within a second distance range, the spring A and the spring B are in a working state, and the spring C is in a non-working state; when the distance between the frame connecting plate and the axle connecting plate is within a third distance range, the spring A, the spring B and the spring C are in working states; wherein the first distance is greater than the second distance, and the second distance is greater than the third distance.

Further, the rigidity switching assembly comprises a gear C rotatably arranged on the connecting rod, a spring pin sliding groove arranged on the gear C along the diameter direction, and a spring pin arranged in the spring pin sliding groove in a sliding manner; and the spring pin in the flexibility changing unit A is connected with the left end of the spring B, and the spring pin in the flexibility changing unit B is connected with the right end of the spring C.

Further, the flexibility control unit comprises a rack A and a rack B which are arranged on the frame connecting plate in a sliding mode along the horizontal direction and can be far away from or close to each other, and a spring D which is arranged between the rack A and the rack B and is always in a compressed state.

The unidirectional composite gear comprises a rotating shaft rotationally arranged on the connecting rod, a gear A fixedly arranged on the rotating shaft, and a gear B arranged on the rotating shaft by adopting a unidirectional bearing; a gear A in the variable flexibility unit A is in meshing transmission with a rack A, and a gear A in the variable flexibility unit B is in meshing transmission with a rack B; a gear B in the variable flexibility unit A is connected with a gear C by a transmission chain, and the gear B in the variable flexibility unit B is connected with the gear C by the transmission chain; when the frame connecting plate moves towards the axle connecting plate, the one-way bearing is in a stop state, and when the frame connecting plate moves away from the axle connecting plate, the one-way bearing is in a start state.

Furthermore, when the distance between the frame connecting plate and the axle connecting plate is within a first distance range, the included angle between the spring pin sliding groove and the horizontal direction is not more thanThe deformation of the spring B and the spring C is zero; when the distance between the frame connecting plate and the axle connecting plate is within a second distance range, the included angle between the spring pin sliding groove in the flexibility changing unit A and the vertical direction is not more thanThe included angle between the spring pin sliding groove in the variable flexibility unit B and the horizontal direction is not more thanThe deformation of the spring C is zero; when the distance between the frame connecting plate and the axle connecting plate is within a third distance range, the included angle between the spring pin sliding groove and the vertical direction is not more than。

Furthermore, an involute chute A and an involute chute B which are symmetrical relative to the compliance control unit are arranged on the vertical plane of the axle connecting plate along the vertical plane, and a roller in the compliance changing unit A and a roller in the compliance changing unit B are respectively positioned in the involute chute A and the involute chute B; when the two rollers roll downwards along the axle connecting plate, the horizontal distance between the two rollers is increased, and the distance between the frame connecting plate and the axle connecting plate is reduced.

Compared with the prior art, the invention has the following advantages and beneficial effects: the vehicle suspension with the flexibility adaptively adjusted along with the height of the gravity center is provided with the flexibility changing unit, the flexibility changing unit can enable a vehicle to form three dynamic balance positions in the driving process, the height of the gravity center of the vehicle can be actively changed in the driving process, and the working states of the spring B and the spring C are triggered; the flexibility control unit is provided with a spring D which is always in a pressed state, so that the gear A, the rack A and the rack B are always in a meshed state, a spring pin chute in the rigidity switching assembly is driven to rotate at a certain angle, and the flexibility change of the vehicle suspension is realized; in addition, involute chute A and involute chute B can further reduce the height of vehicle suspension under the effect of big impact force, increase the motion stability that the vehicle travel. Therefore, the vehicle suspension is reasonable in structure, can actively change the height of the gravity center of the vehicle in the running process of the vehicle, adaptively adjusts the flexibility of the suspension to increase the running stability, and adaptively adjusts the flexibility of the suspension along with the height of the gravity center.

Drawings

Fig. 1 is a schematic diagram of the structural principle of a vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity.

Fig. 2 is a schematic structural view of a unidirectional compound gear in the present invention.

Fig. 3 is a schematic structural view of the stiffness switching assembly in the present invention.

In the drawings, 11-frame connection plate; 12-a damping connection plate; 121-a pin shaft; 13-axle connection plate; 131-involute runner a; 132-involute runner B; 2-a compliance unit a; 3-a compliance changing unit B; 21-connecting rod; 22-unidirectional compound gear; 221-gear a; 222-one-way bearing; 223-gear B; 224-a rotating shaft; 23-a stiffness switching assembly; 231 — gear C; 232-spring pin chute; 233-a spring pin; 24-a transmission chain; 25-a roller; 26-a slide block; 27-spring a; 28-spring B; 29-spring C; 41-rack a; 42-rack B; (ii) a 43-spring D; 51-hydraulic cylinder A; 52-hydraulic cylinder B.

Detailed Description

The invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, the vehicle suspension with flexibility adaptively adjusted according to the height of the center of gravity according to the present invention includes a frame connection plate 11 connected to a vehicle frame, an axle connection plate 13 connected to an axle, a damping connection plate 12 installed between the frame connection plate 11 and the axle connection plate 13, a compliance changing unit, and a compliance control unit.

The flexibility changing unit is rotationally arranged on the damping connecting plate 12, the upper end of the flexibility changing unit slides and is rotationally arranged on the frame connecting plate 11, and the lower end of the flexibility changing unit rolls and is arranged on the axle connecting plate 13 and is used for changing the flexibility between the frame and the axle to adapt to the change of the gravity center height of the vehicle; and the flexibility control unit is arranged on the frame connecting plate 11 in a sliding manner and drives the flexibility kick of the flexibility changing unit. When the acting force on the frame connecting plate 11 is far larger than the initial vehicle gravity, the flexibility changing unit drives the frame connecting plate 11 to move towards the axle connecting plate 13, so that the distance between the frame and the axle is shortened, the effect of reducing the gravity center of the vehicle is achieved, meanwhile, the distance between the frame connecting plate 11 and the axle connecting plate 13 can be switched into different rigidity systems according to an initial set value, and the flexibility of the vehicle suspension is changed. During the lowering of the center of gravity of the vehicle, the compliance control unit will automatically activate spring B28 and spring C29 depending on the range of the center of gravity of the vehicle, i.e., the distance between the frame attachment plate 11 and the axle attachment plate 13.

Preferably, a damping unit for absorbing vibration energy in the vertical direction is further arranged between the damping connecting plate 12 and the axle connecting plate 13; the damping unit comprises a hydraulic cylinder A51 and a hydraulic cylinder B52 which are arranged in parallel along the vertical direction; the cylinder of cylinder a51 and the cylinder of cylinder B52 are connected to axle attachment plate 13, and the output rod of cylinder a51 and the output rod of cylinder B52 are connected to damping attachment plate 12. When the damping connecting plate 12 moves relative to the axle connecting plate 13, the piston rods in the hydraulic cylinder A51 and the hydraulic cylinder B52 perform extension or retraction movement, so that the liquid in the cylinder generates damping force to absorb a part of vibration energy in the vertical direction.

Preferably, the variable compliance unit includes a variable compliance unit a2 and a variable compliance unit B3 which are cross-rotatably mounted on the damping connection plate 12; the flexibility changing unit A2 and the flexibility changing unit B3 respectively comprise a sliding block 26 which is arranged on the frame connecting plate 11 in a sliding mode along the horizontal direction, a connecting rod 21 of which the upper end is rotatably connected with the sliding block 26, the middle part is rotatably connected with the damping connecting plate 12 by a pin shaft 121 and is obliquely arranged, a one-way compound gear 22 which is rotatably arranged on the connecting rod 21 and is meshed with the flexibility control unit, a rigidity switching component 23 which is rotatably arranged on the connecting rod 21 and is positioned below the pin shaft 121, a transmission chain 24 which is connected with the one-way compound gear 22 and the rigidity switching component 23, a roller 25 which is rotatably arranged at the lower end of the connecting rod 21, two ends of the spring A27 are respectively connected with the lower end of the connecting rod 21 in the flexibility changing unit A2 and the lower end of the connecting rod 21 in the flexibility changing unit B3, a spring B28 of which is respectively connected with the rigidity switching component 23 in the flexibility changing unit A2 and the connecting rod 21 in the flexibility changing unit B3, and a spring C29 of which is respectively connected with the connecting rod 21 in the flexibility changing unit A2 and the flexibility changing unit B3; the roller 25 and the axle link plate 13 are connected in rolling contact, and in the initial state, the spring a27, the spring B28 and the spring C29 are parallel to each other. When the frame connecting plate 11 moves towards the axle connecting plate 13, the height of the center of gravity of the whole vehicle is lowered, the two sliding blocks 26 are far away from each other, the flexibility changing unit A2 rotates around the pin shaft 121 in the anticlockwise direction, and the flexibility changing unit B3 rotates around the pin shaft 121 in the clockwise direction.

Preferably, when the distance between the frame connecting plate 11 and the axle connecting plate 13 is in the first distance range, the spring A27 is in the working state, and the spring B28 and the spring C29 are in the non-working state; when the distance between the frame connecting plate 11 and the axle connecting plate 13 is in a second distance range, the spring A27 and the spring B28 are in an operating state, and the spring C29 is in a non-operating state; when the distance between the frame connecting plate 11 and the axle connecting plate 13 is in a third distance range, the spring A27, the spring B28 and the spring C29 are all in working states; wherein the first distance is greater than the second distance, and the second distance is greater than the third distance. The total acting force that frame connecting plate 11 received makes the high three kinds of dynamic balance points that exist of the focus of vehicle, is respectively: a first height balance point, a second height balance point and a third height balance point. When the gravity center of the vehicle slightly vibrates near the first height balance point, the distance between the frame connecting plate 11 and the axle connecting plate 13 is just within a first distance range; when the gravity center of the vehicle slightly vibrates near the second height balance point, the distance between the frame connecting plate 11 and the axle connecting plate 13 is just within the second distance range; when the center of gravity of the vehicle makes a slight vibration near the third height balance point, the distance between the frame attachment plate 11 and the axle attachment plate 13 is within the third distance range.

Preferably, the stiffness switching assembly 23 includes a gear C231 rotatably mounted on the connecting rod 21, a spring pin sliding slot 232 diametrically opened on the gear C231, and a spring pin 233 slidably mounted in the spring pin sliding slot 232; the spring pin 233 in the variable compliance unit a2 is connected to the left end of the spring B28, and the spring pin 233 in the variable compliance unit B3 is connected to the right end of the spring C29. When the spring B28 is in the inactive state, the spring pins 233 in the compliance unit a2 can slide freely in the corresponding spring pin chutes 232, so that the amount of deformation of the spring B28 is zero; when the spring B28 is in working condition, the spring pin 233 connected to the spring B28 is always in contact with the inner side wall of the spring pin sliding slot 232 because the spring pin sliding slot 232 corresponding to the spring B28 rotates by a certain angle and the connecting rod 21 in the compliance unit a2 and the connecting rod 21 in the compliance unit B3 rotate in opposite directions. When the spring C29 is in the inactive state, the spring pins 233 in the compliance unit B3 can slide freely in the corresponding spring pin chutes 232, so that the amount of deformation of the spring C29 is zero; when the spring C29 is in working state, the spring pin 233 connected to the spring C29 is always in contact with the inner side wall of the spring pin sliding slot 232, that is, the spring C29 is in tension state, because the spring pin sliding slot 232 corresponding to the spring C29 rotates by a certain angle and the link 21 in the compliance unit a2 and the link 21 in the compliance unit B3 rotate in opposite directions.

Preferably, the flexibility control unit comprises a rack A41 and a rack B42 which are arranged on the frame connecting plate 11 in a sliding way along the horizontal direction and can be far away or close to each other, and a spring D43 which is arranged between the rack A41 and the rack B42 and is always in a compressed state; the one-way compound gear 22 includes a rotating shaft 224 rotatably mounted on the connecting rod 21, a gear a221 fixedly mounted on the rotating shaft 224, and a gear B223 mounted on the rotating shaft 224 by using a one-way bearing 222; the gear A221 in the variable compliance unit A2 is in meshing transmission with the rack A41, and the gear A221 in the variable compliance unit B3 is in meshing transmission with the rack B42; the gear B223 in the variable compliance unit A2 is connected with the gear C231 by the transmission chain 24, and the gear B223 in the variable compliance unit B3 is connected with the gear C231 by the transmission chain 24; when the frame connecting plate 11 moves towards the axle connecting plate 13, the one-way bearing 222 is in a stop state, that is, the forward rotation of the rotating shaft 224 drives the gear B223 to rotate synchronously; when the frame connecting plate 11 moves away from the axle connecting plate 13, the one-way bearing 222 is in an actuated state, and the rotation of the rotating shaft 224 in the opposite direction does not drive the gear B223 to rotate. Since the two unidirectional compound gears 22 are respectively installed at both sides of the compliance control unit, the rotation directions of the two unidirectional compound gears 22 are always opposite. The present invention provides that the downward movement of the rack a41 and the rack B42 is a forward movement, and the rotation direction of the corresponding one-way compound gear 22 is a forward rotation, and vice versa. That is, for the unidirectional compound gear 22 on the left side, clockwise rotation is forward rotation, and counterclockwise rotation is reverse rotation; however, for the right one-way compound gear 22, the counterclockwise rotation is the forward rotation, and the clockwise rotation is the reverse rotation.

In practice, rack a41 and rack B42 are installed by mounting rack a41 and rack B42 on two sliders 26 that can slide horizontally along the bed plate 11, and then connecting rack a41 and rack B42 with one or more springs D43. When the two sliders 26 move away from each other, the compression amount of the spring D43 is reduced, that is, the rack a41 and the rack B42 move away from each other and keep engaged with the corresponding gear a 221; when the two sliders 26 approach each other, the compression amount of the spring D43 increases, i.e., the rack a41 and the rack B42 approach each other and maintain the meshing transmission with the corresponding gear a 221. Since the gear a221 is always engaged with the rack a41 or the rack B42, when the height of the center of gravity of the vehicle changes, the horizontal distance between the two sliders 26 inevitably changes, and the two gears a221 roll up and down along the rack a41 and the rack B42, respectively.

Preferably, when the distance between the frame connecting plate 11 and the axle connecting plate 13 is within the first distance range, the included angle between the spring pin sliding groove 232 and the horizontal direction is not more thanWhen the deformation amounts of the spring B28 and the spring C29 are zero, and the two sliders 26 move away from or close to each other near the first equilibrium position, the center of gravity of the vehicle slightly vibrates near the first height equilibrium point, and the spring pin 233 can freely slide in the spring pin sliding groove 232; when the distance between the frame connecting plate 11 and the axle connecting plate 13 is within the second distance range, the included angle between the spring pin sliding groove 232 in the flexibility changing unit A2 and the vertical direction is not more thanThe included angle between the spring pin sliding groove 232 in the variable flexibility unit B3 and the horizontal direction is not more thanThe deformation of the spring C29 is zero, and the spring pin 233 connected with the spring C29 can slide freely in the corresponding spring pin sliding slot 232; the spring pins 233 to which the springs B28 are attached are always in contact with the inner side walls of the corresponding spring pin runners 232. When the distance between the frame connecting plate 11 and the axle connecting plate 13 is within the third distance range, the included angle between the spring pin sliding groove 232 and the vertical direction is not more thanNeither spring pin 233 slides relative to the corresponding spring pin runner 232.

Preferably, an involute chute a131 and an involute chute B132 which are symmetrical about the compliance control unit are formed in the vertical plane of the axle connecting plate 13, and the roller 25 in the variable compliance unit a2 and the roller 25 in the variable compliance unit B3 are respectively located in the involute chute a131 and the involute chute B132; as the two rollers 25 roll down the axle attachment plate 13, the horizontal distance between the two increases and the distance between the frame attachment plate 11 and the axle attachment plate 13 decreases.

The working process and working principle of the invention are as follows: it is not assumed that the distance between the frame attachment plate 11 and the axle attachment plate 13 is located in the first distance range, i.e., the center of gravity of the vehicle is highest, and at this time, since the spring B28 and the spring C29 are in the non-operating state, the stiffness of the entire vehicle suspension is mainly formed by the spring a27, so that the stiffness of the vehicle suspension is the smallest and the flexibility is the largest.

When the vehicle runs at a high speed, the frame connecting plate 11 reciprocates up and down due to the unevenness of the ground, when the rack A41 and the rack B42 move downwards, the gear A221 is driven to rotate, at the moment, the one-way bearing 222 is in a stop state, the gear A221 drives the gear B223 to rotate through the rotating shaft 224, and then the gear C231 in the rigidity switching assembly 23 is driven to rotate through the transmission chain 24, so that the spring pin chute 232 gradually inclines from the horizontal direction; when the rack a41 and the rack B42 move upward, the rotation of the gear a221 does not rotate the gear B223 because the one-way bearing 222 is in the actuated state, and therefore the gear C231 does not rotate reversely. The frame connecting plate 11 reciprocates up and down, so that the gear C231 rotates unidirectionally, and the inclination angle of the spring pin sliding groove 232 gradually increases.

If the vehicle is traveling at a higher speed or if the ground is rough, i.e., if the impact force from the ground is greater, the two sliders 26 are further away from each other, so that the center of gravity of the vehicle is lowered, i.e., the distance between the frame attachment plate 11 and the axle attachment plate 13 is within the second distance range. The angle between the spring pin sliding groove 232 of the flexibility changing unit A2 and the horizontal direction is quickly larger than thatThat is, the included angle between the spring pin sliding groove 232 in the variable compliance unit A2 and the vertical direction is smaller thanAt this time, the included angle between the spring pin sliding groove 232 in the compliance varying unit B3 and the horizontal direction is not more thanThus, when the distance between the frame attachment plate 11 and the axle attachment plate 13 is in the second distance range, the stiffness of the vehicle suspension is made up of spring a27 and spring B28, and thus the stiffness of the vehicle suspension increases, i.e., the compliance decreases as the position of the center of gravity decreases.

If the position of the center of gravity of the vehicle is further lowered due to an increase in vibration or impact force, i.e., the position of the center of gravity of the vehicle is the lowest, the distance between the frame attachment plate 11 and the axle attachment plate 13 is in the third distance range. The stiffness of the vehicle suspension is made up of spring a27, spring B28, and spring C29, so the stiffness of the vehicle suspension is once again increased, i.e., compliance is minimized. In any distance range of the frame connection plate 11, the distance between the frame connection plate 11 and the axle connection plate 13 fluctuates slightly, i.e., the vehicle is in dynamic balance. When the impact force of the ground is gradually reduced, the spring pin sliding groove 232 rotates more than 90 degrees, so that the spring pin sliding groove continues to rotate under the action of the spring B28 and the spring C29, namely, the one-way bearing 222 enables the gear B223 to continue to rotate relative to the rotating shaft 224, so that the critical point is passed. Taking the compliance unit A2 as an example, when a vibration force or an impact force acts, the rack a41 drives the gear a221 to rotate counterclockwise, and the one-way bearing 222 in the compliance unit A2 is in a stop state, so that the rotating shaft 224 drives the gear B223 to rotate counterclockwise; when the vibration or impact force disappears, the one-way bearing 222 allows the gear B223 to continue to rotate counterclockwise around the rotating shaft 224 under the action of the spring B28 because the spring pin sliding slot 232 passes the critical point, and the rotating shaft 224 and the gear a221 may be stationary or rotate clockwise.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through creative efforts should fall within the scope of the present invention.