CN115076250A

CN115076250A - Synchronizer gear shifting mechanism, gearbox and operation machine

Info

Publication number: CN115076250A
Application number: CN202210809381.2A
Authority: CN
Inventors: 徐强; 唐让祥; 田乐乐; 陈素姣; 余晓波; 钟家怡; 黎富亮
Original assignee: Liugong Liuzhou Driving Member Co ltd; Guangxi Liugong Machinery Co Ltd
Current assignee: Liugong Liuzhou Driving Member Co ltd; Guangxi Liugong Machinery Co Ltd
Priority date: 2022-07-11
Filing date: 2022-07-11
Publication date: 2022-09-20

Abstract

The invention relates to a gearbox, aiming at solving the problem that the positioning control of a gear shifting position in the existing synchronizer gear shifting mechanism is complex, the invention constructs a synchronizer gear shifting mechanism, a gearbox and an operating machine, wherein the gear shifting mechanism comprises a cylinder device and a reset mechanism which are fixedly connected with a gear shifting push-pull rod, and the reset mechanism comprises a reset spring, a first and a second pushing structure and a first and a second limiting structure; the reset spring is sleeved between the first pushing structure and the second pushing structure on the gear shifting push-pull rod; the first pushing structure and the second pushing structure are fixedly arranged on the push-pull blocking rod and are used for being in abutting contact connection with the corresponding end of the reset spring; the first limiting structure and the second limiting structure are configured to be fixed relative to a box shell of the gearbox, the reset spring is located between the first limiting structure and the second limiting structure, and when the gear shifting push-pull rod is located at the middle position, two ends of the reset spring are correspondingly connected with the first limiting structure and the second limiting structure in an abutting contact mode. The gear shifting positioning device is simple in gear shifting positioning structure and easy and reliable to control.

Description

Synchronizer gear shifting mechanism, gearbox and operation machine

Technical Field

The present disclosure relates to transmissions, and more particularly to a synchronizer shift mechanism, a transmission, and a work machine.

Background

The synchronizer shifts gears to ensure smooth gear shifting and small impact in the whole machine operation or walking process, so the synchronizer is widely used on a walking transmission gearbox of walking equipment.

In the existing synchronizer gear shifting mechanism, a gear shifting fork pushes a synchronizer gear sleeve to enable a corresponding synchronizer cone ring on a synchronizer to be jointed with or separated from a corresponding gear to realize gear shifting. The gear shifting fork is fixedly connected with the gear shifting push-pull rod, and the gear shifting push-pull rod is driven by the gear shifting driving device. The driving device pushes and pulls the shift push-pull rod to move in the axial direction of the shift push-pull rod, so that the shift push-pull rod is in a first engagement position, a middle position and a second engagement position, and the synchronizer is engaged with the first gear, disengaged from the gear and engaged with the second gear correspondingly.

In the shifting process of the synchronizer shifting mechanism, the shifting push-pull rod has three positions, and the precise position control is required to be carried out by controlling the driving device. In the existing synchronizer gear shifting mechanism, a driving device usually adopts a stepping motor and the like, and the gear shifting control is relatively complex.

Disclosure of Invention

The technical problem to be solved by the invention is that the positioning control of the gear shifting position in the existing synchronizer gear shifting mechanism is complex, and the synchronizer gear shifting mechanism, the gearbox and the operation machine are provided, so that the structure and the gear shifting control are simplified.

The technical scheme for realizing the purpose of the invention is as follows: constructing a synchronizer gear shifting mechanism for a gearbox, wherein the synchronizer gear shifting mechanism comprises a synchronizer assembly and a gear shifting push-pull rod, the synchronizer assembly comprises a synchronizer capable of being engaged in two directions and a gear shifting fork connected with a synchronizer gear sleeve of the synchronizer, the gear shifting push-pull rod is arranged in parallel with the axis of a synchronizer gear hub of the synchronizer, and the gear shifting fork is fixedly connected with the gear shifting push-pull rod;

a piston rod of the cylinder device is fixedly connected with the gear shifting push-pull rod, and the cylinder device is used for pushing and pulling the gear shifting push-pull rod to move in the axial direction of the gear shifting push-pull rod;

the reset mechanism comprises a reset spring, a first pushing structure, a second pushing structure, a first limiting structure and a second limiting structure;

the reset spring is sleeved on the gear shifting push-pull rod and is positioned between the first pushing structure and the second pushing structure;

the first pushing structure and the second pushing structure are fixedly arranged on the gear shifting push-pull rod and are used for being in abutting contact connection with the corresponding end of the reset spring;

the first limiting structure and the second limiting structure are configured to be fixed relative to a box shell of the gearbox, the reset spring is located between the first limiting structure and the second limiting structure, and when the gear shifting push-pull rod is located at the middle position, two ends of the reset spring are correspondingly connected with the first limiting structure and the second limiting structure in an abutting contact mode.

In the invention, when the gear shifting push-pull rod moves from the middle position to two ends, one end of the return spring is supported by the first limiting structure or the second limiting structure and is fixed, the other end of the return spring is correspondingly pushed and extruded by the first pushing structure or the second pushing structure to compress and store energy, and when the piston rod of the cylinder device moves to the stroke end, the synchronizer is connected with the corresponding gear. When the synchronizer is disconnected with the gear, the large cavity and the small cavity of the cylinder device are not filled with pressure media, the piston rod freely moves under the action of external force, the gear shifting push-pull rod moves under the pushing of the return spring, when the two ends of the return spring are respectively contacted with the first limiting structure and the second limiting structure, the gear shifting push-pull rod stops moving, the gear shifting push-pull rod is located at the middle position, and the synchronizer is disconnected with the gear. In the invention, when the synchronizer is connected with the gear, the position is controlled by the stroke end limit of the piston rod of the cylinder device, when the synchronizer is disconnected with the gear, the energy stored by the reset spring is used as the power for disconnecting the movement, and the positions of the first limit structure and the second limit structure are used as the positioning positions. The gear shifting positioning structure is simple in structure and easy and reliable to control.

In the gear shifting mechanism of the synchronizer, the two groups of reset mechanisms are provided, and the reset springs of the two groups of reset mechanisms are arranged on the two axial sides of the connecting position of the gear shifting fork and the gear shifting push-pull rod.

In the gear shifting mechanism of the synchronizer, the first limiting structure is formed by a box wall plate which is arranged on a box shell of the gearbox and used for supporting and installing the end part of the gear shifting push-pull rod, and a hole for the first pushing structure on the gear shifting push-pull rod to penetrate through is formed in the box wall plate;

the second limiting structure is composed of a rib plate fixedly arranged on the shell of the gearbox, and a hole for the second pushing structure on the gear shifting push-pull rod to penetrate through is formed in the rib plate.

In the synchronizer gear shifting mechanism, a sleeve is sleeved on the gear shifting push-pull rod, the gear shifting fork is sleeved on the sleeve, the gear shifting fork, the sleeve and the gear shifting push-pull rod are fixedly connected through a fixing pin, and the second pushing structure is formed by an end face, close to the end part of the reset spring, of the sleeve;

the first pushing structure is formed by an end face, close to the end part of the return spring, of a positioning sleeve fixed on the gear shifting push-pull rod or is arranged on an upper step of the gear shifting push-pull rod.

In the synchronizer gear shifting mechanism, the distance between the first pushing structure and the second pushing structure in the reset mechanism is equal to the distance between the first limiting structure and the second limiting structure.

In the synchronizer gear shifting mechanism, the cylinder device is a hydraulic oil cylinder or an air cylinder.

In the synchronizer gear shifting mechanism, the return spring is composed of a spiral spring or a disc spring and gaskets arranged at two ends of the spiral spring or the disc spring.

The technical scheme for realizing the purpose of the invention is as follows: a gearbox is constructed, and is characterized by comprising the synchronizer gear shifting mechanism, wherein two ends of the gear shifting push-pull rod are slidably mounted on a box shell of the gearbox.

In the transmission case, a synchronizer gear hub of the synchronizer assembly is fixedly arranged on an input shaft through a spline, a first driving gear and a second driving gear which can be jointed with the synchronizer assembly are arranged on the input shaft at two axial sides of the synchronizer gear hub, and the first driving gear and the second driving gear are both in rotating connection with the input shaft. The arrangement of the synchronizer assembly on the input shaft reduces the torque load carried on the synchronizer when the transmission is in operation.

In the transmission case, the transmission case further comprises a countershaft assembly, wherein the countershaft assembly comprises a first driven gear, a second driven gear and a countershaft output driving gear which are fixedly arranged on a countershaft; the first driven gear and the second driven gear correspond to the first driving gear and the second driving gear inner core, and the intermediate shaft output driving gear is arranged between the first driven gear and the second driven gear; the input shaft and the intermediate shaft are arranged in parallel, and two ends of each shaft are rotatably arranged on a box shell of the gearbox through bearings.

The technical scheme for realizing the purpose of the invention is as follows: a work machine is constructed which is characterized by the aforementioned gearbox. The work machine may be a loader, an agricultural tractor, a road roller, or the like.

Compared with the prior art, the invention has the advantages that the position is controlled by the stroke end limit of the piston rod of the cylinder device when the synchronizer is connected with the gear, the stored energy of the reset spring is used as the disconnecting moving power when the synchronizer is disconnected, and the first limit structure and the second limit structure are used for position positioning, so that the positioning structure is simple, and the control is simple and reliable.

Drawings

FIG. 1 is a schematic structural view of a synchronizer shift mechanism of the present invention.

Fig. 2 is a schematic diagram of the transmission arrangement of the inventive gearbox.

Fig. 3 is a schematic structural view of the transmission of the present invention.

Part names and serial numbers in the figure:

an input shaft 10, a first gear driving gear 11, and a second gear driving gear 12.

An intermediate shaft 20, a first-gear driven gear 21, a second-gear driven gear 22 and an output driving gear 23.

An output shaft 30 and an output driven gear 31.

Synchronizer 40, shift fork 41, fixed pin 42.

Case 50, first case wall panel 51, second case wall panel 52, case lid 53, first rib 54, second rib 55.

The gear shifting push-pull rod 62, a hydraulic oil cylinder 71, a first return spring 72, a second return spring 73, a first gasket 74, a second gasket 75, a third gasket 76, a fourth gasket 77, a sleeve 78 and a positioning sleeve 79.

Detailed Description

The following description of the embodiments refers to the accompanying drawings.

As shown in fig. 1, the synchronizer shift mechanism in the present embodiment, which is used for a transmission, includes a synchronizer assembly, a shift push-pull rod 62, a cylinder device, and a return mechanism.

The synchronizer assembly comprises a synchronizer 40 and a shifting fork 41, one end of the shifting fork 41 is connected with a synchronizer gear sleeve of the synchronizer 40, and the other end of the shifting fork is fixedly connected with a shifting push-pull rod 62. The synchronizer 40 is a bidirectional engagement synchronizer, and both sides of the synchronizer hub in the axial direction of the synchronizer hub are provided with synchronizer cone rings, and the synchronizer can be engaged with the gears on the corresponding sides or simultaneously kept in a disengaged state with the gears on both sides through the synchronizer cone rings on both sides.

The shift push-pull rod 62 is arranged parallel to the axis of the synchronizer 40 and is mounted at both ends to the wall plate of the case 50 of the transmission.

The cylinder device is a hydraulic cylinder 71, the cylinder body of which is fixedly mounted on the housing 50 of the gearbox, and the piston rod is fixedly connected with the first end of the shift push-pull rod 62. The piston rod of the gear shifting mechanism is stretched and contracted relative to the cylinder body under the action of hydraulic oil in the large cavity or the small cavity, so that the gear shifting push-pull rod 62 is pushed to move in the axial direction of the gear shifting push-pull rod.

A sleeve 78 is sleeved on the gear shifting push-pull rod 62, the gear shifting fork 41 is sleeved on the sleeve 78, and the gear shifting fork 41, the sleeve 78 and the gear shifting push-pull rod 62 are fixedly connected together through a fixing pin 42.

In the synchronizer shift mechanism in this embodiment, there are two sets of cooperating return mechanisms. Each group of reset mechanisms comprises a reset spring, a first pushing structure, a second pushing structure, a first limiting structure and a second limiting structure.

The return spring is sleeved on the shift push-pull rod 62 and is located between the first pushing structure and the second pushing structure.

The first pushing structure and the second pushing structure are both fixedly arranged on the gear shifting push-pull rod 62 and are used for being in abutting contact connection with the corresponding end of the return spring.

The two groups of reset mechanisms are respectively a first group of reset mechanism and a second group of reset mechanism. The first group of reset mechanisms are arranged between the shifting fork and the first end of the shifting push-pull rod.

As shown in fig. 1, in the first set of reset mechanisms, it includes a first reset spring 72, a first end surface 82 of the sleeve forms a second pushing structure in the first set of reset mechanisms, and a second end of the first reset spring 72 abuts against the first end surface 82 of the sleeve through a second gasket 75.

A positioning sleeve 79 is fixed to the shift push-pull rod 62 at a position adjacent to the second end, and the positioning sleeve 79 is fixed to the shift push-pull rod 62 through a positioning nut, a snap ring, or the like. The second end surface 81 of the positioning sleeve 79 facing the sleeve 78 constitutes a first pushing structure in the first set of return mechanisms, and the first end of the first return spring 72 abuts against the second end surface 81 of the positioning sleeve through the first gasket 74. The positioning sleeve 79 is a cylindrical member.

The second end of the gear-shifting push-pull rod 62 is supported and mounted by a first box wall plate 51 of the box shell, the first box wall plate 51 forms a first limiting structure in the first group of resetting mechanisms, and a hole for allowing the positioning sleeve 79 to penetrate is formed in the first box wall plate 51, and the radial dimension of the hole is smaller than that of the first gasket 74. The first box wall plate 51 serves as a first limiting structure that limits the position of the first end of the first return spring 72 when the second end of the first return spring 72 is compressed by being pressed by the sleeve 78.

The first rib 54 fixed relative to the housing 50 forms a second limit structure in the first set of return mechanisms, and the first rib 54 may be provided on the lid 53. The first ribs 54 are provided with holes through which the sleeves 78 pass, the holes having a radial dimension smaller than that of the second spacer 75. The first ribs 54 serve as a second limiting structure that limits the position of the second end of the first return spring 72 when the first end of the first return spring 72 is compressed by the positioning sleeve 79.

The first return spring 72 is located between the second end surface 81 (first urging structure) of the positioning sleeve and the first end surface 82 (second urging structure) of the sleeve, and is also located between the first box wall plate 51 (first limiting structure) and the first rib plate 54 (second limiting structure).

The second set of reset mechanisms is disposed between the shift fork 41 and the first end of the shift push-pull rod 62.

The second group of reset mechanisms comprises a second reset spring 73, a second end surface 83 of the sleeve forms a second pushing structure in the second group of reset mechanisms, the second pushing structure is used for pushing a first end of the second reset spring 73, and the first end of the second reset spring 73 is connected with the second end surface 83 of the sleeve in a butting and contacting manner through a third gasket 76.

The shift push-pull rod 62 is provided with a radial step 84 at a position adjacent to the first end, the radial step 84 forms a first pushing structure in the second set of return mechanisms, and the second end of the second return spring 73 abuts against the radial step 84 through the fourth gasket 77.

The second box wall plate 52 of the box housing for supporting and mounting the first end of the shift push-pull rod constitutes a first limit structure of the second set of return mechanisms, and the second box wall plate 52 is provided with a hole for the second end of the shift push-pull rod 62 to pass through, and the radial dimension of the hole is smaller than that of the fourth gasket 77. The second box wall plate 52 serves as a first stopper structure for defining the position of the second end of the second return spring 73 when the first end of the second return spring 73 is compressed by being pressed by the sleeve 78.

The second rib 55 fixed relative to the housing forms a second limit structure in the second set of reset mechanisms, and the second rib 55 may be provided on the lid 53. The second ribs 55 are provided with holes through which the second end of the sleeve 78 passes, the holes having a radial dimension smaller than the radial dimension of the third spacer 76. The second rib 55 serves as a second limiting structure that limits the position of the first end of the second return spring 73 when the second end of the second return spring 73 is compressed by the radial step 84 of the shift push-pull rod 62.

As shown in fig. 1, the hydraulic cylinder 71 is controlled by a three-position four-way valve 91, two working oil ports of the three-position four-way valve 91 are respectively communicated with a large cavity and a small cavity of the hydraulic cylinder 71, an oil inlet of the three-position four-way valve 91 is connected with a pressure oil source, and an oil return port of the three-position four-way valve 91 is connected with a hydraulic oil tank.

The present embodiment provides a two-speed transmission, as shown in fig. 2 and fig. 3, the transmission in the present embodiment is a two-gear transmission, and the transmission includes a housing 50, an input shaft assembly, a countershaft assembly, an output shaft assembly, and the synchronizer shift mechanism in the previous embodiments.

The input shaft assembly comprises an input shaft 10 and a first driving gear and a second driving gear which are connected to the input shaft 10 in a rotating mode, and the first driving gear and the second driving gear are a second-gear transmission driving gear 11 and a first-gear transmission driving gear 12 correspondingly. Two ends of the input shaft 10 are respectively connected on the box shell in a rotating way through bearings. The first gear drive gear 12 and the second gear drive gear 12 are rotatably mounted on the input shaft 10 through bearings.

The synchronizer assembly in the synchronizer gear shifting mechanism comprises a synchronizer 40 and a gear shifting fork 41, wherein the synchronizer 40 is arranged on the input shaft 10, is positioned between the first gear driving gear 12 and the second gear driving gear 11 and is used for being jointed with the first gear driving gear 12 or the second gear driving gear 11, so that power is transmitted to the first gear driving gear 12 or the second gear driving gear 11 from the input shaft through the synchronizer. A synchronizer gear hub of the synchronizer is connected with an input shaft 10 through a spline, and the synchronizer is connected with a first-gear driving gear 12 or a second-gear driving gear 11 in a joint mode through synchronizer cone rings on two end faces of the synchronizer.

The intermediate shaft assembly comprises an intermediate shaft 20, a first driven gear and a second driven gear which are fixedly arranged on the intermediate shaft 20, and an output driving gear 23. In the two-speed gearbox, the first driven gear and the second driven gear correspond to a first-gear driven gear 22 and a second-gear driven gear 21; the first-gear driven gear 22 and the second-gear driven gear 21 are meshed with the first-gear drive gear 12 and the second-gear drive gear 11, respectively. The output driving gear 23 is disposed between the first-stage driven gear 22 and the second-stage driven gear 21.

The axial arrangement position of the output driving gear 23 is opposite to the synchronizer 40, the output driving gear 23 is arranged by utilizing the space between the first-gear driven gear 22 and the second-gear driven gear 21 in the radial direction of the synchronizer 40, the internal arrangement of the gearbox is compact, and meanwhile, the output driving gear 23 is arranged between the first-gear driven gear 22 and the second-gear driven gear 21, so that the mounting bearing force of two ends of the intermediate shaft 20 is relatively uniform. The output shaft assembly comprises an output shaft 30 and an output driven gear 31 fixedly arranged on the output shaft 30, and the output driven gear 31 is meshed with the output driving gear 23. The first-gear driven gear 22, the second-gear driven gear 21 and the output driving gear 23 are all connected with the intermediate shaft through splines. The output driven gear 23 is connected to the output shaft by splines.

The input shaft 10, the intermediate shaft 20 and the output shaft 30 are arranged parallel to each other, and both ends of each shaft are rotatably mounted on the casing of the transmission through bearings.

The embodiment also provides a working machine which can be a loader with an electric motor as a power device, and can also be an agricultural tractor or a road roller. In the working machine, the electric motor is connected to the input shaft of the transmission in the above-described embodiment, and the hydraulic cylinder 71 is controlled by controlling the three-position four-way valve 91 to engage the synchronizer 40 with the first gear drive gear 12 or the second gear drive gear 11. The power transmission route is as follows: the power is transmitted to the output shaft 30 through the input shaft 10, the synchronizer 40, the first gear driving gear 12 or the second gear driving gear 11 engaged with the synchronizer 40, the corresponding first gear driven gear 22 or the second gear driven gear 21, the intermediate shaft 20, the output driving gear 23 and the output driven gear 31 in sequence, and then is transmitted to the drive axle through the transmission shaft connected with the output shaft 30, so that the walking drive of the working machine is realized.

In the above embodiment, the synchronizer 40 is disposed on the input shaft 10, and the torque on the input shaft 10 is small relative to the synchronizer disposed on the intermediate shaft 20, and therefore the torque borne on the synchronizer 40 is small. Arranging the synchronizer 40 on the input shaft 10 reduces its torque carrying requirements and increases the service life of the synchronizer 40. In addition, the output driving gear 23 is arranged between the first-gear driven gear 22 and the second-gear driven gear 21, the axial arrangement position is opposite to the synchronizer 40, the space in the radial direction of the synchronizer 40 is utilized, the compact arrangement inside the gearbox is facilitated, and meanwhile, the output driving gear 23 is located between the first-gear driven gear 22 and the second-gear driven gear 21 and is located in the middle of the intermediate shaft, so that the bearing force of the mounting shafts at two ends of the intermediate shaft is relatively uniform.

The shifting process of the synchronizer shift mechanism in the above embodiment is positioned as follows:

when the three-position four-way valve 91 is switched from the middle position to the right position, the pressure oil source is communicated with the large cavity of the hydraulic oil cylinder 71 through the three-position four-way valve 91, and the small cavity of the hydraulic oil cylinder 71 is communicated with the hydraulic oil tank through the three-position four-way valve 91. The piston rod of the hydraulic oil cylinder 71 extends out under the action of the large-cavity pressure oil, and the gear shifting push-pull rod 62 drives the gear shifting fork 41 to move towards the direction of the two-gear driving gear and compresses the second end of the first return spring 72 and the second end of the second return spring 73. When the piston rod of the hydraulic cylinder 71 extends to the end of the stroke, the shift push-pull rod 62 moves to the second gear engagement position, and the synchronizer 40 engages with the second gear driving gear 11, so that the transmission operates in the second gear. At the end of the piston rod extension stroke of hydraulic cylinder 71, synchronizer 40 engages with the secondary drive gear 11.

When the three-position four-way valve 91 is switched from the middle position to the left position, the pressure oil source is communicated with the small cavity of the hydraulic oil cylinder 71 through the three-position four-way valve 91, and the large cavity of the hydraulic oil cylinder 71 is communicated with the hydraulic oil tank through the three-position four-way valve 91. The piston rod of the hydraulic cylinder 71 retracts under the action of the small chamber pressure oil, and the shift push-pull rod 62 drives the shift fork 41 to move towards the first gear driving gear 12 (towards the first gear engagement position), and compresses the first end of the first return spring 72 and the first end of the second return spring 73. When the piston rod of the hydraulic cylinder 71 is retracted to the end of the stroke, the shift push-pull rod 62 is moved to the first gear engagement position, and the synchronizer 40 engages with the first gear driving gear 12, so that the transmission operates in the second gear. At the end of the retraction stroke of the piston rod of hydraulic cylinder 71, synchronizer 40 engages first gear drive gear 12.

When the three-position four-way valve 91 is positioned at the middle position, the large cavity and the small cavity of the hydraulic oil cylinder 71 are simultaneously communicated with the hydraulic oil tank through the three-position four-way valve 91, oil liquid in the large cavity and the small cavity of the hydraulic oil cylinder 71 does not have a pushing effect on a piston of the hydraulic oil cylinder 71, and the hydraulic oil cylinder 71 is in a normal state (a free state).

When the three-position four-way valve 91 is switched from the right position to the middle position, the shift push-pull rod 62 moves from the second gear engagement position to the middle position under the extrusion pushing of the second end of the first return spring and the second end of the second return spring until the second gasket 75 at the end of the first return spring contacts the first rib plate 54; the fourth washer 77 at the end of the second return spring contacts the second box wall plate 52. After the shift push-pull rod 62 moves from the second gear engagement position to the neutral position, the synchronizer 40 is disengaged from the second gear drive gear 11.

When the three-position four-way valve 91 is switched from the left position to the center position, the shift push-pull rod 62 is pushed by the first end of the first return spring 72 and the first end of the second return spring 73 to move from the first-gear engagement position to the center position until the first return spring end portion first pad 74 contacts the first case wall plate 51 and the second return spring end portion third pad 76 contacts the second rib 55. After the shift push-pull rod 62 moves from the first-gear engagement position to the neutral position, the synchronizer is disengaged from the first-gear driving gear 12.

When the shift push-pull rod 62 is in the neutral position, the shift fork 41 is in a position such that the synchronizer 40 is not engaged with the first gear driving gear 12 and the second gear driving gear 11, and the transmission is in the neutral state.

In this embodiment, the piston of hydraulic cylinder 71 has a two-end travel limit, so that no additional stroke control of the cylinder piston is required during the first and second gear shifting engagement. When the piston of the hydraulic oil cylinder 71 moves to the limit position in the large cavity direction, the synchronizer is engaged with the first-gear driving gear 12 to realize the first-gear work of the gearbox; when the piston of the hydraulic oil cylinder 71 moves to the limit position in the small cavity direction, the synchronizer is engaged with the second-gear driving gear 11 to realize the second-gear work of the gearbox; when the neutral gear is required to be shifted, the three-position four-way valve 91 of the hydraulic oil cylinder 71 is controlled to be in the neutral position, and the shift push-pull rod 62 is moved to the neutral position under the combined action of the first return spring 72 and the second return spring 73, so that the synchronizer 40 is simultaneously disengaged from the first gear driving gear 12 and the second gear driving gear 11. In the gear shifting process, the state of the hydraulic oil cylinder is controlled only, namely three states of oil filling in the large cavity, oil filling in the small cavity or oil filling in both the large cavity and the small cavity of the hydraulic oil cylinder are controlled, and the specific position of the gear shifting push-pull rod is not required to be controlled, so that the gear shifting control is simple and reliable.

In this embodiment, the hydraulic cylinder may be replaced with an air cylinder.

In the above embodiment, the two sets of reset mechanisms are adopted in the shift mechanism, in order to meet the requirement of reducing the strength performance of a single spring under the condition of providing enough disengaging thrust on the shift push-pull rod, and if the reset spring has enough strength, one of the two sets of reset mechanisms can be omitted.

In the above embodiment, the first box wall plate 51, the second box wall plate 52, the first rib 54, and the second rib 55 are parts that are fixed relative to the box shell, and in the specific implementation, other structures that are fixed relative to the box shell may be used instead according to design requirements. The positioning sleeve 79, the sleeve 78, and the radial step 84 are structures fixed to the shift push-pull rod 62 for a return spring contact connection, and may take other forms, such as snap rings, pins, etc., depending on design requirements.

Claims

1. A synchronizer gear shifting mechanism is used for a gearbox and comprises a synchronizer assembly and a gear shifting push-pull rod, wherein the synchronizer assembly comprises a synchronizer capable of being engaged in two directions and a gear shifting fork connected with a synchronizer gear sleeve of the synchronizer;

2. The synchronizer gear shift mechanism according to claim 1, wherein said return mechanisms are provided in two sets, and return springs of said two sets of said return mechanisms are respectively disposed on both axial sides of a position where a shift fork is connected to said shift push-pull rod.

3. The synchronizer gear shifting mechanism according to claim 1 or 2, wherein the first limiting structure is formed by a box wall plate which is arranged on the shell of the gearbox and used for supporting and installing the end part of the gear shifting push-pull rod, and a hole for the first pushing structure on the gear shifting push-pull rod to pass through is formed in the box wall plate;

the second limiting structure is formed by a rib plate fixedly arranged on the shell of the gearbox, and a hole for the second pushing structure on the gear shifting push-pull rod to penetrate through is formed in the rib plate.

4. The synchronizer shifting mechanism according to claim 3, wherein a sleeve is sleeved on the shifting push-pull rod, the shifting fork is sleeved on the sleeve, the shifting fork, the sleeve and the shifting push-pull rod are fixedly connected through a fixing pin, and the second pushing structure is formed by an end face, adjacent to the end of the return spring, of the sleeve;

5. The synchronizer shift mechanism according to claim 3, wherein a distance between the first push structure and the second push structure in the reset mechanism is equal to a distance between the first limit structure and the second limit structure.

6. The synchronizer shift mechanism of claim 1 wherein said cylinder means is a hydraulic cylinder or an air cylinder.

7. A gearbox characterised by a synchronizer shift mechanism according to any one of claims 1 to 6, the shift push-pull rod being slidably mounted at both ends to the housing of the gearbox.

8. The transmission of claim 7, wherein the synchronizer hub of the synchronizer assembly is fixedly mounted to the input shaft by a spline, and a first drive gear and a second drive gear are mounted to the input shaft at axially opposite sides of the synchronizer hub and are engageable with the synchronizer assembly, the first drive gear and the second drive gear both being rotatably coupled to the input shaft.

9. The transmission of claim 8, further comprising a countershaft assembly including a first driven gear, a second driven gear, and a countershaft output drive gear fixedly mounted on a countershaft; the first driven gear and the second driven gear correspond to the first driving gear and the second driving gear inner core, and the intermediate shaft output driving gear is arranged between the first driven gear and the second driven gear; the input shaft and the intermediate shaft are arranged in parallel, and two ends of each shaft are rotatably arranged on a box shell of the gearbox through bearings.

10. A work machine characterized by a gearbox according to any of claims 7-9.