Shift damper structure and shift method thereof

Abstract

This invention provides a shifting buffer structure and shifting method. One end of a piston shaft forms a piston and is slidably disposed within a cylinder, while the other end extends axially into the stepped inner hole of a shift fork shaft. A first spacer and a second spacer are respectively provided at the front and rear positions of the thin shaft at the front of the shift fork shaft. The first and second spacers are axially slidable relative to the piston shaft and the shift fork shaft. A spring is clamped between the first and second spacers. A limit is provided at the tail opening of the stepped inner hole of the shift fork shaft, and a limit step with a constriction hole is provided at the front end of the stepped inner hole. The first spacer abuts against the tail opening of the shift fork shaft for limitation, and the second spacer abuts against the limit step at the front end of the shift fork shaft for limitation. The spring is gradually compressed and stores force, and the thrust of the shift fork shaft gradually increases from a small state, thereby enabling the synchronizer to obtain continuous and stable synchronizing force during the locking and synchronizing phases, reducing wear and abnormal meshing of the locking teeth caused by sudden changes in driving force.

Description

Technical Field

[0001] This invention relates to the field of gear shifting technology, and in particular to a gear shifting buffer structure and a gear shifting method thereof. Background Technology

[0002] Heavy-duty gearboxes and engineering machinery transmission systems typically employ pneumatic shifting mechanisms for gear switching. Existing structures generally include a cylinder, piston, fork shaft, shift fork, and synchronizer assembly. After air enters the cylinder, it pushes the piston, fork shaft, and shift fork to move axially, thereby driving the gear sleeve to engage with the synchronizer ring, cone ring, and gear seat to complete synchronization and meshing. Because the piston, fork shaft, and shift fork are mostly rigidly connected, the driving force output from the cylinder is directly transmitted to the synchronizer assembly.

[0003] Existing technologies CN217977331U discloses a double-spring buffer shift fork mechanism, which improves the stability of the shift wheel engagement by setting a spring on the shift fork shaft; CN204921958U discloses an obstructed shift fork assembly, which uses an elastic element to cause the shift fork to yield when shifting is obstructed; CN113915330A discloses a shifting device with a return spring, which uses spring energy storage to achieve gear reset. All of the above prior technologies involve improvements to the shift fork or spring structure, but mainly address the problems of shift fork obstruction yielding, shift engagement, or gear reset.

[0004] During synchronizer shifting, after the gear sleeve moves to the synchronized position, it temporarily stops moving due to the frictional torque between the synchronizer ring and the cone ring. At this time, the cylinder continues to intake air, which can cause the air pressure to gradually increase. This results in the pneumatic force acting directly on the locking teeth of the synchronizer ring through the rigid connection structure, potentially causing wear on the locking teeth, unreliable locking, or tooth breakage. After synchronization is complete, the gear sleeve continues to move into the meshing stage. Due to reduced resistance and the continued cylinder pressure, the piston, fork shaft, shift fork, and gear sleeve are prone to continuous acceleration, causing significant impact and shifting noise when the end face of the gear sleeve contacts the end face of the gear. Summary of the Invention

[0005] The main objective of this invention is to provide a shifting buffer structure and shifting method, which solves the technical problems of concentrated impact during the synchronization locking stage, meshing impact after synchronization completion, and large shifting noise caused by rigid force transmission in existing pneumatic shifting structures.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a shifting buffer structure, wherein one end of the piston shaft forms a piston and is slidably disposed in the cylinder, and the other end extends axially into the stepped inner hole of the shift fork shaft; The thin shaft at the front of the shift fork shaft is provided with a first spacer and a second spacer at the front and rear positions respectively. The first spacer and the second spacer can slide axially relative to the piston shaft and the shift fork shaft. A spring is clamped between the first spacer and the second spacer. The tail opening of the stepped inner hole of the shift fork shaft is provided with a limit, and the front end of the stepped inner hole of the shift fork shaft is provided with a shrinkage hole with a limit step. The first spacer abuts against the opening at the tail of the shift fork shaft, and the second spacer abuts against the upper limit of the step at the front end of the shift fork shaft.

[0007] In the preferred embodiment, the front step of the stepped inner hole of the shift fork shaft is the shoulder of the shift fork shaft, the second spacer abuts against the upper limit of the shoulder of the shift fork shaft, and the thin shaft body at the front of the shift fork shaft extends into the front constriction hole.

[0008] In the preferred embodiment, a large nut is provided at the tail of the stepped inner hole of the shift fork shaft. The inner wall of the large nut is slidably sleeved with the thick shaft of the piston shaft, and the outer wall of the large nut is snapped or threadedly connected to the tail of the stepped inner hole of the shift fork shaft. The inner end face of the large nut forms a first shoulder, and the first spacer abuts against the end face of the first shoulder for limitation.

[0009] In the preferred embodiment, the rear end of the large nut is provided with a radially extending annular flange, which abuts against the end face of the stepped inner hole of the shift fork shaft for limiting its position.

[0010] In the preferred embodiment, the piston shaft has a raised threaded portion at its front end, a small nut on the threaded portion, the small nut being threadedly connected to the threaded portion, and the second spacer abutting against the end face of the small nut for limiting its position.

[0011] In the preferred embodiment, the outer surface diameter of the small nut is smaller than the inner diameter of the constricted hole at the front end of the stepped inner hole of the shift fork shaft.

[0012] In the preferred embodiment, the cylinder is a two-way cylinder, with the first and second air inlets of the cylinder connected to the air chambers on both sides of the piston, respectively.

[0013] In the preferred embodiment, one side surface of the first spacer abuts against the stepped end face where the piston shaft's thick and thin shafts meet to form a limiting position.

[0014] In the preferred embodiment, the spring is a compression spring, and the spring stiffness is configured to output a preset synchronous force to the shift fork shaft under maximum compression. When the third shoulder on the cylinder piston abuts against the limiting surface of the housing, the axial distance between the first and second spacers reaches its minimum, and the spring is in its maximum compression state.

[0015] A shifting method with a shift buffer structure, the method comprising: S1. When the gear sleeve is in the initial neutral position, the spring between the first and second spacers is in a free state, and the stiffness of the spring is set according to the preset maximum synchronous force. S2. Compressed gas is introduced into the first air inlet, causing the piston shaft to move in the first direction. The first shoulder pushes the first spacer to move in the first direction. The first spacer compresses the spring, and the spring is compressed to generate stored force. The spring drives the shift fork shaft and shift fork to move in the first direction through the second spacer and the shift fork shaft shoulder, so as to push the gear sleeve to move to the synchronous position, so that the thrust of the shift fork shaft gradually increases from zero. S3. When the gear sleeve is limited by the frictional torque between the synchronizing ring and the cone ring and stays in the synchronizing position, the piston shaft continues to move in the first direction until the third shoulder abuts against the housing, so that the spring is compressed to the maximum compression state, the stored force formed by the spring compression begins to be released, and the maximum synchronizing force is output to the shift fork shaft. S4. After the synchronization ring and the cone ring are synchronized, the stored force released by the spring is used to push the second spacer, the shift fork shaft and the shift fork to continue to move along the first direction, so that the tooth sleeve engagement teeth of the tooth sleeve pass over the locking teeth of the synchronization ring and mesh with the engagement teeth of the cone ring until the tooth sleeve moves to the meshing position and the spring returns to the free state. During this process, the thrust of the shift fork shaft gradually decreases from the maximum synchronization force to zero. S5. Compressed gas is introduced into the second air inlet, causing the piston shaft to move in the second direction opposite to the first direction. The small nut pushes the second spacer to move in the second direction and compresses the spring. The spring pushes the first spacer to move in the second direction. The first spacer drives the shift fork shaft and shift fork to move in the second direction via the front end face of the large nut, so as to complete the reverse shifting.

[0016] This invention provides a shift buffer structure and shift method thereof. By setting the piston shaft and shift fork shaft as separate structures that can move relative to each other, and by setting a spring between the first spacer and the second spacer, the driving force of the cylinder is flexibly transmitted to the shift fork shaft through the first spacer, the spring and the second spacer, avoiding the direct transmission of pneumatic impact force to the synchronizer, thereby reducing the impact on the synchronizer ring locking teeth.

[0017] This application utilizes the cooperation of a first shoulder, a first spacer, a second spacer, a shift fork shaft shoulder, and a spring. During the movement of the gear sleeve from the neutral position to the synchronized position, the spring gradually compresses and stores force, while the thrust of the shift fork shaft gradually increases, providing a smooth synchronizing force to the synchronizer. After the third shoulder abuts against the housing, the spring reaches its maximum compression state. After synchronization is complete, the spring releases its stored force and pushes the shift fork shaft and shift fork to continue moving, allowing the gear sleeve to complete subsequent engagement and reducing impact and noise upon reaching the engagement point.

[0018] This application also utilizes the cooperation of a large nut, a small nut, a first spacer, a second spacer, and a spring to ensure that both the first and second air inlets can generate buffered force transmission, balancing the smoothness of forward and reverse shifting. The overall structure is compact and easy to assemble. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a diagram of the shift buffer structure of the present invention; Figure 2 This is a flowchart of the shift buffer drive process of the present invention; Figure 3 This is a diagram of the pneumatic shifting structure of the prior art of this invention; Figure 4 This is a planar structural diagram of the prior art of this invention; Figure 5 This is a structural diagram of the synchronizer of the present invention; Figure 6 This is a schematic diagram of the synchronizer shifting position of the present invention.

[0020] In the diagram: Cylinder 1; First air inlet 1a; Second air inlet 1b; Piston shaft 2; First shoulder 2a; Second shoulder 2b; Third shoulder 2c; Shift fork shaft 3; Shift fork shaft shoulder 3a; Shift fork 4; Gear sleeve 5; Gear sleeve engagement tooth 5a; Synchronizing ring 6; Synchronizing ring locking tooth 6a; Cone ring 7; Cone ring engagement tooth 7a; Gear seat 8; Gear seat tooth 8a; Large nut 9; First spacer 10; Spring 11; Second spacer 12; Small nut 13; Housing 14; Gear 15. Detailed Implementation

[0021] Example 1 like Figure 1-6 As shown, a shifting buffer structure is provided, in which one end of the piston shaft 2 forms a piston and is slidably disposed in the cylinder 1, and the other end extends axially into the stepped inner hole of the shift fork shaft 3. The thin shaft at the front of the shift fork shaft 3 is provided with a first spacer 10 and a second spacer 12 at the front and rear positions respectively. The first spacer 10 and the second spacer 12 can slide axially relative to the piston shaft 2 and the shift fork shaft 3. The spring 11 is clamped between the first spacer 10 and the second spacer 12. The tail opening of the three-step inner hole of the shift fork shaft is provided with a limit, and the front end of the three-step inner hole of the shift fork shaft is provided with a shrinkage hole with a limit step. The first spacer 10 abuts against the opening at the tail of the shift fork shaft 3, and the second spacer 12 abuts against the upper limit of the front limit step of the shift fork shaft 3.

[0022] The buffer structure includes a cylinder 1, a piston shaft 2, a shift fork shaft 3, a first spacer 10, a spring 11, and a second spacer 12. The cylinder 1 provides bidirectional pneumatic force. One end of the piston shaft 2 forms a piston within the cylinder 1, and the piston shaft 2 reciprocates axially with changes in the air pressure within the cylinder 1. The other end of the piston shaft 2 extends axially into the stepped inner hole of the shift fork shaft 3. The piston shaft 2 and the shift fork shaft 3 are not rigidly integrated but form a separate force transmission structure capable of relative axial displacement.

[0023] The shift fork shaft 3 is a sleeve-type shaft with a stepped inner hole. The shift fork 4 is installed on the outer side of the shift fork shaft 3, and the shift fork 4 is engaged in the toothed sleeve groove 5a of the toothed sleeve 5. When the shift fork shaft 3 moves axially, the shift fork 4 synchronously pushes the toothed sleeve 5 to move, so that the toothed sleeve engaging teeth 5a engage with the synchronizing ring locking teeth 6a, the conical ring engaging teeth 7a and the toothed seat teeth 8a in sequence, thereby realizing the shifting action of the synchronizer.

[0024] The first spacer 10 and the second spacer 12 are arranged axially back and forth along the thin shaft area at the front of the shift fork shaft 3. Both the first spacer 10 and the second spacer 12 are ring-shaped structures and form an axially sliding fit with the piston shaft 2 and the shift fork shaft 3. The spring 11 is disposed between the first spacer 10 and the second spacer 12, so that an elastic force transmission path is formed between the piston shaft 2 and the shift fork shaft 3. When the piston shaft 2 moves, the piston shaft 2 first pushes the first spacer 10, the first spacer 10 compresses the spring 11, and the spring 11 then transmits the thrust to the shift fork shaft 3 through the second spacer 12, thereby avoiding the direct rigid action of the pneumatic force of the cylinder 1 on the synchronizing ring 6 and the synchronizing ring locking tooth 6a.

[0025] The stepped inner bore of the shift fork shaft 3 has an opening limiting structure at its tail end and a limiting step with a constriction hole at its front end. The first spacer 10 is located near the opening at the tail end of the stepped inner bore, and the second spacer 12 is located near the constriction hole at the front end of the stepped inner bore. The opening limiting structure at the tail end of the stepped inner bore and the limiting step at the front end together limit the installation space of the first spacer 10, the spring 11, and the second spacer 12, ensuring that the spring 11 is always coaxially aligned with the piston shaft 2 and the shift fork shaft 3, preventing skewing, detachment, or unstable force transmission during gear shifting.

[0026] In the preferred embodiment, the front step of the stepped inner hole of the shift fork shaft 3 is the shift fork shaft shoulder 3a, the second spacer 12 abuts against the upper limit of the shift fork shaft shoulder 3a, and the thin shaft body at the front of the shift fork shaft 3 extends into the front constriction hole.

[0027] The limiting step at the front end of the stepped inner hole of the shift fork shaft 3 forms a shoulder 3a, and the second spacer 12 abuts against the shoulder 3a. When the piston shaft 2 moves along the first direction and compresses the spring 11 through the first spacer 10, the spring 11 pushes the second spacer 12 to exert force on the shoulder 3a, and the second spacer 12 then transmits the spring force to the shift fork shaft 3, thereby driving the shift fork 4 and the toothed sleeve 5 to move. The thin shaft at the front of the shift fork shaft 3 extends into the front constriction hole, so that the shift fork shaft 3 remains coaxially guided during reciprocating movement, reducing the possibility of radial displacement between the shift fork shaft 3 and the piston shaft 2.

[0028] In the preferred embodiment, a large nut 9 is provided at the tail of the stepped inner hole of the shift fork shaft 3. The inner wall of the large nut 9 is slidably sleeved with the thick shaft of the piston shaft 2, and the outer wall of the large nut 9 is snapped or threadedly connected to the tail of the stepped inner hole of the shift fork shaft 3. The inner end face of the large nut 9 forms a first shoulder 2a, and the first spacer 10 abuts against the end face of the first shoulder 2a for limitation.

[0029] A large nut 9 is located at the tail end of the stepped inner hole of the shift fork shaft 3. The inner wall of the large nut 9 is slidably sleeved with the thicker shaft of the piston shaft 2, allowing the piston shaft 2 to move axially within the large nut 9. The outer wall of the large nut 9 is connected to the tail end of the stepped inner hole of the shift fork shaft 3 by a snap-fit ​​or threaded connection, ensuring that the large nut 9 remains stably installed relative to the shift fork shaft 3. A first shoulder 2a is formed on the inner end face of the large nut 9, and a first spacer 10 abuts against the end face of the first shoulder 2a. When the piston shaft 2 moves along the first direction, the first shoulder 2a can stably transmit the axial thrust to the first spacer 10.

[0030] The first shoulder 2a, the first spacer 10, the spring 11, the second spacer 12, and the shift fork shaft shoulder 3a constitute a continuous force transmission chain. After the first shoulder 2a pushes the first spacer 10 to move, the first spacer 10 compresses the spring 11, the spring 11 pushes the second spacer 12, and the second spacer 12 then pushes the shift fork shaft shoulder 3a, so that the shift fork shaft 3 obtains a gradually increasing shifting thrust. This force transmission chain converts the air pressure of the cylinder 1 into the flexible thrust of the spring 11, avoiding sudden impacts on the synchronizer at the synchronization position.

[0031] In the preferred embodiment, the rear end of the large nut 9 is provided with a radially extending annular flange, which abuts against the end face of the stepped inner hole of the shift fork shaft 3 for limiting its position.

[0032] An annular flange is located at the rear end of the large nut 9 and extends radially outward. The annular flange abuts against the end face of the stepped inner hole of the shift fork shaft 3, ensuring reliable positioning of the large nut 9 after axial installation. The annular flange prevents the large nut 9 from shifting into the stepped inner hole under shifting impact, and also allows the large nut 9 to withstand the axial force transmitted by the first spacer 10 during reverse shifting. After a stable connection is formed between the large nut 9 and the shift fork shaft 3, the position of the first shoulder 2a remains fixed, thus ensuring a consistent initial force transmission position for the first spacer 10 each time it compresses the spring 11.

[0033] In the preferred embodiment, the piston shaft 2 has a raised threaded part at the front end, and a small nut 13 is provided on the threaded part. The small nut 13 is threadedly connected to the threaded part, and the second spacer 12 abuts against the end face of the small nut 13 for limiting.

[0034] The outer diameter of the small nut 13 is smaller than the inner diameter of the constricted hole at the front end of the stepped inner hole of the shift fork shaft 3.

[0035] The piston shaft 2 has a raised threaded portion at its front end, and a small nut 13 is threadedly connected to the threaded portion. The small nut 13 is located on the side of the second spacer 12 near the front end of the fork shaft 3, and the second spacer 12 abuts against the end face of the small nut 13. When air enters through the second air inlet 1b, the piston shaft 2 moves along the second direction, and the small nut 13 moves with the piston shaft 2 and pushes the second spacer 12. The second spacer 12 compresses the spring 11, and the spring 11 pushes the first spacer 10. The first spacer 10 then drives the fork shaft 3 to move along the second direction via the large nut 9. Thus, both the first air inlet 1a and the second air inlet 1b can form a spring-buffered force transmission when air enters.

[0036] The outer diameter of the small nut 13 is smaller than the inner diameter of the constricted bore at the front end of the stepped inner hole of the shift fork shaft 3. This dimensional relationship allows the small nut 13 to move axially with the piston shaft 2 within the constricted bore region, preventing the small nut 13 from getting stuck against the inner wall of the constricted bore. A necessary radial clearance is maintained between the small nut 13 and the constricted bore, while axial limiting and force transmission are achieved through the second spacer 12, the shift fork shaft shoulder 3a, and the spring 11, ensuring the continuity of action during reverse shifting.

[0037] In the preferred embodiment, cylinder 1 is a bidirectional cylinder, and the first air inlet 1a and the second air inlet 1b of cylinder 1 are respectively connected to the air chambers on both sides of the piston.

[0038] Cylinder 1 is a bidirectional cylinder, with a first intake port 1a and a second intake port 1b connecting to the air chambers on both sides of the piston. When air enters through the first intake port 1a, the piston shaft 2 moves along a first direction, and the gear sleeve 5 moves from position 0 to X1 and X3. When air enters through the second intake port 1b, the piston shaft 2 moves along a second direction, and the gear sleeve 5 moves from position 0 to Y1 and Y3. The first and second directions are opposite, allowing the shift buffer structure to be suitable for gear switching in two opposite directions.

[0039] In the preferred embodiment, one side surface of the first spacer 10 abuts against the stepped end face where the thick and thin shafts of the piston shaft 2 intersect to form a limit.

[0040] In the preferred embodiment, spring 11 is a compression spring, and the stiffness of spring 11 is configured to output a preset synchronous force to the shift fork shaft 3 under maximum compression. When the third shoulder 2c on the piston of cylinder 1 abuts against the limiting surface of housing 14, the axial distance between the first spacer 10 and the second spacer 12 reaches its minimum, and the spring 11 is in its maximum compression state.

[0041] One side surface of the first spacer 10 abuts against the stepped end face at the junction of the thick and thin shafts of the piston shaft 2. This stepped end face provides an axial reference for the first spacer 10, allowing it to obtain a clear force-bearing position when the piston shaft 2 moves. The second shoulder 2b on the piston shaft 2 is located in the stepped transition area of ​​the piston shaft 2. The second shoulder 2b, together with the stepped inner hole of the shift fork shaft 3, the area where the second spacer 12 and the small nut 13 are located, form an assembly clearance and axial guiding space, preventing interference between the piston shaft 2 and the inner wall of the shift fork shaft 3 during reciprocating movement.

[0042] Spring 11 is a compression spring. The stiffness of spring 11 can be determined by the spring material, spring wire diameter, effective number of turns, free length, and installation preload, so that spring 11 can output a preset synchronizing force to shift fork shaft 3 to meet the synchronization requirements of synchronizer under maximum compression. The stiffness of spring 11 is determined during the structural design and assembly stage. During gear shifting, compression and release of stored force are achieved through the relative displacement between the first spacer 10 and the second spacer 12.

[0043] The third shoulder 2c is located on the side of the piston shaft 2 near the cylinder 1 and engages with the limiting surface of the housing 14. When the gear sleeve 5 reaches the synchronous position corresponding to X1 or Y1, the shift fork shaft 3 and the second spacer 12 temporarily stop moving due to the obstruction of the synchronous ring locking tooth 6a. The piston shaft 2 can still continue to move relative to the shift fork shaft 3, and the first spacer 10 further compresses the spring 11. When the third shoulder 2c abuts against the limiting surface of the housing 14, the axial distance between the first spacer 10 and the second spacer 12 reaches its minimum, and the spring 11 reaches its maximum compression state. The hard limiting of the housing 14 prevents the continuous pneumatic force of the cylinder 1 from directly pushing the shift fork shaft 3. Instead, the housing 14 bears the subsequent stroke of the piston shaft 2, and the spring 11 thus forms the maximum stored force for subsequent engagement.

[0044] Example 2 Further explanation in conjunction with Example 1, such as Figure 1-6 The structure shown illustrates a shifting method using a shifting buffer structure, the method comprising: S1. When the gear sleeve 5 is in the initial neutral position, the spring 11 between the first spacer 10 and the second spacer 12 is in a free state, and the stiffness of the spring 11 is set according to the preset maximum synchronous force. S2. Compressed gas is introduced into the first air inlet 1a, causing the piston shaft 2 to move in the first direction. The first shoulder 2a pushes the first spacer 10 to move in the first direction. The first spacer 10 compresses the spring 11, and the spring 11 is compressed to form stored force. The spring 11 drives the shift fork shaft 3 and the shift fork 4 to move in the first direction through the second spacer 12 and the shift fork shaft shoulder 3a, so as to push the gear sleeve 5 to move to the synchronous position, so that the thrust of the shift fork shaft 3 gradually increases from zero. S3. When the gear sleeve 5 is restricted by the frictional torque between the synchronous ring 6 and the cone ring 7 and stays in the synchronous position, the piston shaft 2 continues to move in the first direction until the third shoulder 2c abuts against the housing 14, so that the spring 11 is compressed to the maximum compression state, the stored force formed by the compression of the spring 11 begins to be released, and the maximum synchronous force is output to the shift fork shaft 3. S4. After the synchronization ring 6 and the cone ring 7 are synchronized, the stored force released by the spring 11 pushes the second spacer 12, the shift fork shaft 3 and the shift fork 4 to continue moving in the first direction, causing the tooth sleeve 5a of the tooth sleeve 5 to pass over the locking tooth 6a of the synchronization ring and mesh with the engagement tooth 7a of the cone ring, until the tooth sleeve 5 moves to the meshing completed position and the spring 11 returns to the free state. During this process, the thrust of the shift fork shaft 3 gradually decreases from the maximum synchronization force to zero. S5. Compressed gas is introduced into the second air inlet 1b, causing the piston shaft 2 to move in the second direction opposite to the first direction. The small nut 13 pushes the second spacer 12 to move in the second direction and compresses the spring 11. The spring 11 pushes the first spacer 10 to move in the second direction. The first spacer 10 drives the shift fork shaft 3 and shift fork 4 to move in the second direction via the front end face of the large nut 9, so as to complete the reverse shifting.

[0045] S1 stage corresponds to Figure 2 Position 0. At this time, the gear sleeve 5 is in the initial neutral position, the gear sleeve engaging tooth 5a is engaged with the gear seat tooth 8a, and the gear sleeve engaging tooth 5a has not yet engaged with the cone ring engaging tooth 7a to form the target gear position. The spring 11 between the first spacer 10 and the second spacer 12 is in a free state, and the shift fork shaft 3 does not bear the shifting thrust generated by the spring 11. The stiffness of the spring 11 is selected based on the frictional torque that needs to be overcome when the synchronizer is synchronized, the allowable force of the synchronizing ring locking tooth 6a, and the shifting stroke of the gear sleeve 5, so that the spring 11 has a stable synchronizing thrust under maximum compression.

[0046] In stage S2, compressed gas is introduced through the first intake port 1a, and the piston shaft 2 moves along the first direction. The first shoulder 2a pushes the first spacer 10 to move, and the first spacer 10 compresses the spring 11, which then stores force. The spring 11 abuts against the shoulder 3a of the shift fork shaft via the second spacer 12, driving the shift fork shaft 3 and the shift fork 4 to move along the first direction. The shift fork 4 pushes the toothed sleeve 5 from position 0 to X1. When the toothed sleeve engagement tooth 5a approaches the synchronizing ring locking tooth 6a, a frictional torque is generated between the synchronizing ring 6 and the cone ring 7. The synchronizing ring locking tooth 6a blocks the toothed sleeve engagement tooth 5a, causing the toothed sleeve 5 to remain at X1. During the process from position 0 to X1, the compression of the spring 11 gradually increases, and the thrust obtained by the shift fork shaft 3 gradually increases from zero.

[0047] In stage S3, the gear sleeve 5 remains at X1, the shift fork shaft 3 and the second spacer 12 are temporarily stopped by the synchronizer, and the piston shaft 2 continues to move in the first direction under air pressure. The first spacer 10 continues to compress the spring 11 until the third shoulder 2c abuts against the housing 14. At this time, the distance between the first spacer 10 and the second spacer 12 is the smallest, the spring 11 is in the maximum compression state, and outputs the maximum synchronizing force to the shift fork shaft 3. The spring 11 completes its energy storage in this state and enters the ready-to-release state. After the synchronizing ring 6 and the cone ring 7 complete synchronization, the stored energy of the spring 11 can be converted into an elastic thrust that drives the shift fork shaft 3 to continue moving.

[0048] In stage S4, the frictional torque between the synchronizing ring 6 and the conical ring 7 decreases, and the synchronizing ring locking tooth 6a releases its obstruction of the sleeve engagement tooth 5a. The spring 11 releases its stored force, and the second spacer 12 pushes the shift fork shaft 3 and the shift fork 4 to continue moving in the first direction. The sleeve engagement tooth 5a passes over the synchronizing ring locking tooth 6a and enters the engagement state with the conical ring engagement tooth 7a via a transition position not separately marked, finally reaching X3. At X3, the sleeve 5 completes the power transmission engagement with the corresponding structures of the gear seat 8, the conical ring 7, and the gear 15. The end face of the sleeve 5 is limited by the stroke of the end face of the gear 15. At this time, the spring 11 returns to its free state, and the thrust of the shift fork shaft 3 gradually decreases to zero, thereby preventing the sleeve 5 from continuing to be subjected to large aerodynamic impacts when fully engaged.

[0049] In stage S5, compressed gas is introduced into the second air inlet 1b, and the piston shaft 2 moves in a second direction opposite to the first direction. The small nut 13 pushes the second spacer 12 to move in the second direction, and the second spacer 12 compresses the spring 11. The spring 11 pushes the first spacer 10, and the first spacer 10 then drives the shift fork shaft 3 and the shift fork 4 to move via the front end face of the large nut 9. The shift fork 4 pushes the gear sleeve 5 from position 0 to Y1, and the gear sleeve 5 performs reverse synchronization at Y1. After synchronization is completed, the spring 11 releases its stored force, and the gear sleeve 5 continues to move from Y1 to Y3 to complete the reverse engagement. The movement process from Y1 to Y3 is symmetrical to the movement process from X1 to X3, so that the shift buffer structure has the functions of spring storage, synchronous buffering, and gradual energy release during both forward and reverse shifting.

[0050] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A shift buffer structure, characterized in that: One end of the piston shaft (2) forms a piston and is slidably disposed in the cylinder (1), while the other end extends axially into the stepped inner hole of the shift fork shaft (3); The thin shaft at the front of the shift fork shaft (3) is provided with a first spacer (10) and a second spacer (12) at the front and rear positions respectively. The first spacer (10) and the second spacer (12) can slide axially relative to the piston shaft (2) and the shift fork shaft (3). The spring (11) is clamped between the first spacer (10) and the second spacer (12). The tail opening of the stepped inner hole of the shift fork shaft (3) is provided with a limit, and the front end of the stepped inner hole of the shift fork shaft (3) is provided with a shrinkage hole of the limit step; The first spacer (10) abuts against the opening at the tail of the shift fork shaft (3) and the second spacer (12) abuts against the upper limit of the front limit step of the shift fork shaft (3).

2. The shift buffer structure according to claim 1, characterized in that: The front step of the stepped inner hole of the shift fork shaft (3) is the shoulder (3a) of the shift fork shaft. The second spacer (12) abuts against the upper limit of the shoulder (3a) of the shift fork shaft, and the thin shaft body at the front of the shift fork shaft (3) extends into the front constriction hole.

3. The shift buffer structure according to claim 1, characterized in that: The tail of the stepped inner hole of the shift fork shaft (3) is provided with a large nut (9). The inner wall of the large nut (9) is slidably sleeved with the thick shaft of the piston shaft (2), and the outer wall of the large nut (9) is snapped or threadedly connected to the tail of the stepped inner hole of the shift fork shaft (3). The inner end face of the large nut (9) forms a first shoulder (2a), and the first spacer (10) abuts against the end face of the first shoulder (2a) for limitation.

4. The shift buffer structure according to claim 3, characterized in that: The rear end of the large nut (9) is provided with a radially extending annular flange, which abuts against the end face of the stepped inner hole of the shift fork shaft (3) for limiting.

5. The shift buffer structure according to claim 1, characterized in that: The piston shaft (2) has a raised threaded part at the front end, and a small nut (13) is provided on the threaded part. The small nut (13) is threadedly connected to the threaded part, and the second spacer (12) abuts against the end face of the small nut (13) for limiting.

6. The shift buffer structure according to claim 5, characterized in that: The outer diameter of the small nut (13) is smaller than the inner diameter of the constricted hole at the front end of the stepped inner hole of the fork shaft (3).

7. The shift buffer structure according to claim 1, characterized in that: The cylinder (1) is a two-way cylinder, and the first air inlet (1a) and the second air inlet (1b) of the cylinder (1) are respectively connected to the air chambers on both sides of the piston.

8. The shift buffer structure according to claim 1, characterized in that: The surface of one side of the first spacer (10) abuts against the stepped end face where the thick and thin shafts of the piston shaft (2) meet, forming a limit.

9. The shift buffer structure according to claim 1, characterized in that: The spring (11) is a compression spring, and the stiffness of the spring (11) is configured to output a preset synchronous force to the shift fork shaft (3) under maximum compression. When the third shoulder (2c) on the piston of cylinder (1) abuts against the limiting surface of housing (14), the axial distance between the first spacer (10) and the second spacer (12) reaches its minimum, and the spring (11) is in the maximum compression state.

10. A shifting method with a shifting buffer structure, characterized in that: The method, employing the shift buffer structure of any one of claims 1-9, comprises: S1. When the gear sleeve (5) is in the initial neutral position, the spring (11) between the first spacer (10) and the second spacer (12) is in a free state, and the stiffness of the spring (11) is set according to the preset maximum synchronous force. S2. Compressed gas is introduced into the first air inlet (1a) to make the piston shaft (2) move in the first direction. The first shoulder (2a) pushes the first spacer (10) to move in the first direction. The first spacer (10) compresses the spring (11). The spring (11) is compressed to form stored force. The spring (11) drives the shift fork shaft (3) and the shift fork shaft shoulder (3a) to move in the first direction to push the gear sleeve (5) to move to the synchronous position, so that the thrust of the shift fork shaft (3) gradually increases from zero. S3. When the gear sleeve (5) is restricted by the frictional torque between the synchronous ring (6) and the cone ring (7) and stays in the synchronous position, the piston shaft (2) continues to move in the first direction until the third shoulder (2c) abuts against the housing (14), so that the spring (11) is compressed to the maximum compression state, the stored force formed by the compression of the spring (11) begins to be released, and the maximum synchronous force is output to the shift fork shaft (3); S4. After the synchronization ring (6) and the cone ring (7) are synchronized, the stored force released by the spring (11) is used to push the second spacer (12), the shift fork shaft (3) and the shift fork (4) to continue moving in the first direction, so that the tooth sleeve engagement tooth (5a) of the tooth sleeve (5) passes over the locking tooth (6a) of the synchronization ring and engages with the engagement tooth (7a) of the cone ring until the tooth sleeve (5) moves to the engagement completion position and the spring (11) returns to the free state. During this process, the thrust of the shift fork shaft (3) gradually decreases from the maximum synchronization force to zero. S5. Compressed gas is introduced into the second air inlet (1b) to make the piston shaft (2) move in the second direction opposite to the first direction. The small nut (13) pushes the second spacer (12) to move in the second direction and compresses the spring (11). The spring (11) pushes the first spacer (10) to move in the second direction. The first spacer (10) drives the shift fork shaft (3) and shift fork (4) to move in the second direction through the front end face of the large nut (9) to complete the reverse shifting.

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