A high-low side belt return spring gear assembly and gear shifting method

Abstract

The present application relates to the technical field of power shift transmission, in particular to a high-low gear shift assembly with side return spring and a gear shift method, which integrates a piston seat, a valve seat, a gear shift electromagnetic valve and a shift fork shaft into a whole, sets a partition ring on the piston seat, and separates the internal space of the piston seat, wherein a first through hole of the valve seat and the outer wall of the partition ring and the inner wall of the piston seat form a low gear working oil cavity, a second through hole of the valve seat and the inner wall of the partition ring form a high gear working oil cavity, and a return spring is respectively sleeved on the shift fork shaft in the low gear working oil cavity and the high gear working oil cavity, no matter the process of hanging low gear or the process of hanging high gear, the return spring on the compressed side will generate resistance to slow down the moving speed of the shift fork shaft, reduce the impact force between the shaft shoulder of the shift fork shaft and the spring washer, and the impact force between the right end surface of the shift fork shaft and the bottom of the piston seat, so as to reduce the risk of material wear and crushing to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power shift transmission, in particular to a high-low gear shift assembly with side return spring and a shift method. BACKGROUND

[0002] For operation vehicles such as sanitation vehicles, hoisting vehicles and watering vehicles, in addition to the driving function, torque is obtained from the power system through an external rear power take-off to provide operation power for the upper equipment.

[0003] At present, the control methods of high-low gear shift devices in China are pneumatic, manual and hydraulic control,

[0004] For manual control, domestic operation vehicles are generally heavy and large, the shift resistance is large, the strength of manual operation of the shift mechanism is large, the burden on the driver is increased, the driver is prone to fatigue, safety hazards are buried, the shift force is difficult to control, the driving skill is required, and the driving pleasure and safety of the operation vehicle are greatly reduced. For pneumatic control, gas is compressible, is easily affected by changes in the external load of the operation vehicle, has poor shift stability, has large action hysteresis, and has small shift force, which has certain influence on the shift response time and the shift accuracy. In order to prevent the risk of gas leakage, the gas tightness of the overall shift mechanism is required to be high, which increases the complexity of the mechanism and the processing cost.

[0005] For the existing hydraulic shift device, the high-low gear shift response is fast, the shift is smooth and there is no impact, which is an important evaluation index of the shift performance of the transmission. During the shift process of the high-low gear shift device, the shift fork shaft driven by the hydraulic pressure rapidly drives the shift fork to move, which is easy to cause impact to the joint sleeve, thereby causing gear spline wear, breakage of the connecting bolt on the shift fork, mutual scratching of the shift fork shaft and the hole wall surface matched therewith to damage the sealing ring, oil leakage and oil channeling to fail to effectively shift, and the sleeve and the gear are stuck after shifting to fail to disengage. SUMMARY

[0006] In order to overcome the defects of the prior art, the purpose of the present application is to provide a high-low gear shift assembly with side return spring and a shift method, so as to solve the technical problems of gear spline wear, breakage of the connecting bolt on the shift fork, mutual scratching of the shift fork shaft and the hole wall surface matched therewith to damage the sealing ring, oil leakage and oil channeling to fail to effectively shift, and the sleeve and the gear are stuck after shifting to fail to disengage in the prior art.

[0007] The present application is realized by the following technical solutions:

[0008] The application discloses a gear shifting assembly with high-low gear side belt return springs, which comprises a piston seat, a shift fork shaft, a partition ring, a first return spring, a second return spring, a valve seat, a gear shifting electromagnetic valve and a shift fork.

[0009] Preferably, the mounting end of the piston seat is provided with external threads and a first sealing ring mounting groove, the piston seat is assembled in the piston seat mounting hole through the external threads, and a third O-shaped sealing ring is arranged between the first sealing ring mounting groove and the inner wall of the piston seat mounting hole.

[0010] Further, the partition ring is provided with a through hole, the shift fork shaft passes through the through hole, one end of the partition ring is provided with a plurality of oil passing cutouts in the radial direction, one end of the oil passing cutout is sequentially communicated with the oil passing hole and the first through hole, and the other end of the oil passing cutout is communicated into the piston seat to form a low gear working oil channel; the other end of the partition ring is annularly provided with a second sealing ring mounting groove, and a second O-shaped sealing ring is arranged between the second sealing ring mounting groove and the inner wall of the piston seat mounting hole.

[0011] Preferably, the shift fork shaft is provided with a first shaft sleeve in the low gear working oil cavity, one end of the first return spring is arranged in the first shaft sleeve, and the other end of the first return spring is fixed at the inner wall end of the piston seat.

[0012] Preferably, the inner wall end of the piston seat in the high gear working oil cavity is provided with a spring washer, the shift fork shaft is provided with a second shaft sleeve in the high gear working oil cavity, one end of the second return spring is arranged on the second shaft sleeve, and the other end of the second return spring is fixed at the spring washer.

[0013] Preferably, the gear shifting assembly further comprises two self-locking steel balls, the two self-locking steel balls are arranged on the shift fork shaft outside the piston seat in a sliding mode, the shift fork shaft is provided with two self-locking grooves on the outer end of the piston seat, and the two steel balls are arranged on the two self-locking grooves in a sliding mode along the movement direction of the shift fork shaft.

[0014] Preferably, the first O-shaped sealing ring is sleeved between the shift fork shaft and the piston seat, and the fourth O-shaped sealing ring is sleeved between the shift fork shaft and the spacer ring.

[0015] Preferably, the shift fork shaft is provided with a groove at an end portion of the shift fork, and the shift fork is fixed on the shift fork shaft by inserting bolts into the groove.

[0016] Preferably, the shift electromagnetic valve is a three-position four-way electromagnetic switch valve, comprising an oil inlet, an oil return, a high gear oil outlet and a low gear oil outlet, the high gear oil outlet is communicated with the second through hole, the low gear oil outlet is communicated with the first through hole, one end of the oil inlet is communicated with the high gear oil outlet and the low gear oil outlet respectively, the other end is connected with a pressure oil output device, the oil return is connected with the high gear oil outlet and the low gear oil outlet respectively, and the other end is connected with an oil tank.

[0017] A shift method of a shift assembly with high and low gears and side return springs, based on the above-mentioned shift assembly with high and low gears and side return springs, comprising the following processes:

[0018] When the high gear works, the electric signal drives the valve core of the shift electromagnetic valve to move, so that the oil passage between the oil inlet and the high gear oil outlet is conducted, the pressure oil enters from the oil inlet of the shift electromagnetic valve, enters the high gear working oil cavity through the high gear oil outlet, and pushes the shift fork shaft to move to the high gear; in the process of moving to the high gear, the shaft end face of the shift fork shaft will compress the second return spring in the high gear working oil cavity, so as to be subjected to the spring force generated by the second return spring, the spring force and the force of the high gear working oil are opposite in direction, the shift fork pushes the second shaft sleeve to connect the high gear gear with the sliding sleeve tooth seat on the output shaft, so as to realize synchronous high-speed power output; when the ECU cuts off the electric signal on the shift electromagnetic valve, the high gear working pressure oil flows back to the oil tank through the oil return oil channel of the shift electromagnetic valve, so that the oil pressure applied to the shift fork shaft is removed, and then the shift fork shaft returns to the intermediate position under the action of the spring force generated by the compressed second return spring.

[0019] When the low gear works, the electric signal drives the valve core of the shift electromagnetic valve to move, so that the oil passage between the oil inlet and the low gear oil outlet is conducted, the pressure oil enters from the oil inlet of the shift electromagnetic valve, enters the low gear working oil cavity through the low gear oil outlet, and pushes the shift fork shaft to move to the low gear; in the process of moving to the low gear, the shaft end face of the shift fork shaft will compress the first return spring in the low gear working oil cavity, so as to be subjected to the spring force generated by the first return spring, the spring force and the force of the low gear working oil are opposite in direction, the shift fork pushes the first shaft sleeve to connect the low gear gear with the sliding sleeve tooth seat on the output shaft, so as to realize synchronous low-speed power output; when the ECU cuts off the electric signal on the shift electromagnetic valve, the low gear working pressure oil flows back to the oil tank through the oil return oil channel of the shift electromagnetic valve, so that the oil pressure applied to the shift fork shaft is removed, and then the shift fork shaft returns to the intermediate position under the action of the spring force generated by the compressed first return spring.

[0020] The middle position is between the high gear position and the low gear position, when the shift fork shaft is in the middle position, the shift fork makes the engagement sleeve neither engaged with the high gear gear nor engaged with the low gear gear, so as to realize the neutral position, so that the power take-off device completes the power take-off operation in the parking state.

[0021] Compared with the prior art, the present application has the following beneficial technical effects:

[0022] The present application provides a high-low gear side return spring gear shifting assembly, which integrates the piston seat, the valve seat, the gear shifting electromagnetic valve and the shift fork shaft as a whole, a partition ring is arranged on the piston seat, the partition ring divides the internal space of the piston seat, wherein the first through hole of the valve seat and the outer wall of the partition ring and the inner wall of the piston seat form a low gear working oil cavity, the second through hole of the valve seat and the inner wall of the partition ring form a high gear working oil cavity, and return springs are respectively sleeved on the shift fork shaft in the low gear working oil cavity and the high gear working oil cavity, no matter the process of engaging the low gear or the process of engaging the high gear, the return spring on the compressed side will generate resistance to slow down the moving speed of the shift fork shaft, and the impact force between the shaft shoulder of the shift fork shaft and the spring washer and the impact force between the right end face of the shift fork shaft and the bottom of the internal cavity of the piston seat are reduced, thereby reducing the risk of material wear and crushing to a certain extent, the spring force of the return spring is smaller than the oil pressure, and the phenomenon of not engaging the gear or dropping the gear will not occur. The spring force of the return spring is larger than the self-locking spring force acting on the shift fork shaft through the self-locking steel ball, so that the shift fork shaft can smoothly return to the middle position from the high / low gear.

[0023] Further, the mounting end of the piston seat is provided with an external thread and a first sealing ring mounting groove, the external thread is assembled in the piston seat mounting hole, the stability of the installation between the piston seat and the valve seat is improved, the third O-shaped sealing ring is sleeved between the first sealing ring mounting groove and the inner wall of the piston seat mounting hole, the sealing property between the piston seat and the valve seat is improved, a plurality of oil passing holes are annularly arranged on the mounting end of the piston seat, the oil passing holes are respectively communicated with the first through hole and the outer wall of the partition ring to form a low gear working oil passage, and the pressure oil can flow into the low gear working oil cavity.

[0024] Further, the partition ring is provided with a through hole, the shift fork shaft is arranged through the through hole, a plurality of oil passing notches are radially arranged at one end of the partition ring, one end of the oil passing notch is sequentially communicated with the oil passing hole and the first through hole, and the other end is communicated to the piston seat to form a low gear working oil passage, so that the pressure oil can flow into the low gear working oil cavity; the other end of the partition ring is annularly provided with a second sealing ring mounting groove, the second O-shaped sealing ring is sleeved between the second sealing ring mounting groove and the inner wall of the piston seat mounting hole, and the sealing property between the partition ring and the valve seat is improved.

[0025] Further, two self-locking steel balls are arranged on the outside of the piston seat, and the shifter shaft is provided with two self-locking grooves on the outer end of the piston seat, and the two steel balls are arranged on the two self-locking grooves along the movement direction of the shifter shaft, and the position state of the two self-locking steel balls on the shifter shaft can feed the gear position signal to the ECU, facilitating the conversion of high and low gears.

[0026] Further, the first O-shaped sealing ring is arranged between the shifter shaft and the piston seat, and the fourth O-shaped sealing ring is arranged between the shifter shaft and the spacer ring, thereby improving the sealing performance between the shifter shaft and the piston seat and the spacer ring.

[0027] The application also provides a gear shifting method of the gear shifting assembly with return springs, the low gear working oil cavity and the high gear working oil cavity are formed by engaging the valve seat and the spacer ring in the piston seat, and the return springs are arranged in the low gear working oil cavity and the high gear working oil cavity, the two return springs have the same characteristics, specifically, the initial compression amount, the spring stiffness, the spring inner diameter, the cross-section diameter pitch and the free height are the same, the return springs arranged on both sides of the oil cavity can reduce the impact of the shifter shaft on the oil cylinder during gear engagement and reduce the wear of the gear spline caused by the engagement of the sleeve, the return springs can store energy and reduce heat loss, and the buffer effect can increase the gear shifting smoothness, and the spring force is smaller than the hydraulic pressure, and has no influence on the response speed of the high and low gear engagement. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic view of the high and low gear shifting device in the application in the low gear working position;

[0029] Figure 2 It is a schematic view of the high and low gear shifting device in the application in the high gear working position;

[0030] Figure 3 It is a schematic view of the high and low gear shifting device in the application in the high gear working position;

[0031] Figure 4 It is a three-dimensional view of the high and low gear shifting device in the application in the high gear working position;

[0032] Figure 5 It is a side view of the valve seat structure in the application;

[0033] Figure 6 It is a sectional view of the valve seat in the application;

[0034] Figure 7 It is a schematic view of the piston seat in the application;

[0035] Figure 8 is a schematic diagram of the spacer ring in the present application;

[0036] Figure 9 is a schematic diagram of the upper power logic of the shift solenoid valve in the present application.

[0037] In the figure: 1 is a piston seat; 2 is a shift fork shaft; 3 is a spring washer; 4 is a second shaft sleeve; 5 is a spacer ring; 6 is a first return spring; 7 is a second return spring; 8 is a self-locking steel ball; 9 is a groove; 10 is a valve seat; 11 is a shift solenoid valve; 12 is a shift fork; 13 is a first O-shaped sealing ring; 14 is a second O-shaped sealing ring; 15 is a third O-shaped sealing ring; 16 is a fourth O-shaped sealing ring; 17 is a first shaft sleeve; 1-1 is an oil passage hole; 1-2 is an external thread; 1-3 is a first sealing ring installation groove; 5-1 is an oil passage notch; 5-2 is a second sealing ring installation groove; 10-1 is a piston seat installation hole; 10-2 is a shift solenoid valve installation hole; 10-3 is a first through hole; 10-4 is a second through hole. DETAILED DESCRIPTION

[0038] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0039] The present application will be described in further detail below in conjunction with the accompanying drawings:

[0040] The present application aims to provide a high-low gear shift assembly with side return springs and a gear shift method, so as to solve the technical problems of gear spline wear, breakage of connecting bolts on the shift fork, mutual scratching of the shift fork shaft and the hole wall surface to cause damage of the sealing ring, oil leakage and oil channeling, and the gear shift after the sleeve and the gear are stuck and cannot be disengaged.

[0041] Specifically, according to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the high-low gear shift assembly with side return springs comprises a piston seat 1, a shift fork shaft 2, a spacer ring 5, a first return spring 6, a second return spring 7, a valve seat 10, a shift solenoid valve 11 and a shift fork 12; according to Figure 5 and Figure 6As shown, the valve seat 10 is provided with a piston seat mounting hole 10-1 and a gear shifting solenoid mounting hole 10-2, and a first through hole 10-3 and a second through hole 10-4 are provided in parallel between the piston seat mounting hole 10-1 and the gear shifting solenoid mounting hole 10-2; the mounting end of the piston seat 1 is assembled in the piston seat mounting hole 10-1, the oil supply end of the gear shifting solenoid 11 is assembled in the gear shifting solenoid mounting hole 10-2, and the oil supply end of the gear shifting solenoid 11 is communicated with the first through hole 10-3 and the second through hole 10-4, respectively; the spacer ring 5 is assembled in the piston seat 1, and the internal space of the piston seat 1 is divided, wherein the first through hole 10-3 of the valve seat 10, the outer wall of the spacer ring 5 and the inner wall of the piston seat 1 form a low gear working oil cavity; the second through hole 10-4 of the valve seat 10 and the inner wall of the spacer ring 5 form a high gear working oil cavity; one end of the yoke shaft 2 extends into the piston seat 1 through the valve seat 10 and the spacer ring 5 in sequence, the first return spring 6 is sleeved on the yoke shaft 2 in the low gear working oil cavity, and the second return spring 7 is sleeved on the yoke shaft 2 in the high gear working oil cavity, and the other end of the yoke shaft 2 is assembled with the yoke 12.

[0042] Specifically, according to Figure 7 As shown, the mounting end of the piston seat 1 is provided with an external thread 1-2 and a first sealing ring mounting groove 1-3, the external thread 1-2 is assembled in the piston seat mounting hole 10-1, and the first sealing ring mounting groove 1-3 is sleeved with the third O-shaped sealing ring 15 between the inner wall of the piston seat mounting hole 10-1; a plurality of oil passing holes 1-1 are annularly arranged on the mounting end of the piston seat 1, and the oil passing holes 1-1 are communicated with the first through hole 10-3 and the outer wall of the spacer ring 5 to form a low gear working oil passage.

[0043] Among them, according to Figure 8 As shown, the spacer ring 5 is provided with a through hole, the yoke shaft 2 is arranged through the through hole, one end of the spacer ring 5 is provided with a plurality of oil passing cutouts 5-1 along the radial direction, one end of the oil passing cutout 5-1 is communicated with the oil passing hole 1-1 and the first through hole 10-3 in sequence, and the other end is communicated into the piston seat 1 to form a low gear working oil passage; the other end of the spacer ring 5 is annularly provided with a second sealing ring mounting groove 5-2, and the second sealing ring mounting groove 5-2 is sleeved with the second O-shaped sealing ring 14 between the inner wall of the piston seat mounting hole 10-1.

[0044] Specifically, the first shaft sleeve 17 is sleeved on the yoke shaft 2 in the low gear working oil cavity, one end of the first return spring 6 is sleeved in the first shaft sleeve 17, and the other end is fixed at the inner wall end of the piston seat 1.

[0045] Specifically, the spring washer 3 is arranged at the inner wall end of the piston seat 1 in the high gear working oil cavity, the second shaft sleeve 4 is sleeved on the yoke shaft 2 in the high gear working oil cavity, one end of the second return spring is sleeved on the second shaft sleeve 4, and the other end is fixed at the spring washer 3.

[0046] Specifically, the application further comprises two self-locking steel balls 8, which are slidingly arranged on the shifter shaft 2 outside the piston seat 1, wherein the shifter shaft 2 is provided with two self-locking grooves on the outer end of the piston seat 1, and the two steel balls 8 are slidingly arranged on the two self-locking grooves along the movement direction of the shifter shaft 2.

[0047] Specifically, the shifter shaft 2 is provided with a groove 9 at the end of the assembled shifter 12, and the shifter 12 is fixed on the shifter shaft 2 by being inserted into the groove 9 through a bolt.

[0048] Specifically, the shift electromagnetic valve 11 is a three-position four-way electromagnetic switch valve, which comprises an oil inlet, an oil return, a high gear oil outlet and a low gear oil outlet, the high gear oil outlet is communicated with the second through hole 10-4, the low gear oil outlet is communicated with the first through hole 10-3, one end of the oil inlet is communicated with the high gear oil outlet and the low gear oil outlet, and the other end is connected with a pressure oil output device, the oil return is connected with the high gear oil outlet and the low gear oil outlet, and the other end is connected with an oil return tank.

[0049] The high-low gear side shift assembly with return springs in the application is driven by hydraulic pressure. After receiving the high-low gear shift instruction sent by the driver, the ECU controls the electric signal to make the shift electromagnetic valve installed on the valve seat switch the working position of the valve core, so that the oil of the target gear is conducted

[0050] The application further provides a shift method of the high-low gear side shift assembly with return springs, which is based on the high-low gear side shift assembly with return springs and comprises the following processes.

[0051] When the high gear works, the electric signal drives the valve core of the shift electromagnetic valve 11 to move, so that the oil path between the oil inlet and the high gear oil outlet is conducted, the pressure oil enters the shift electromagnetic valve 11 from the oil inlet, enters the high gear working oil chamber through the high gear oil outlet, and pushes the shifter shaft 2 to move to the high gear; during the movement of the shifter shaft 2 to the high gear, the shaft end face of the shifter shaft 2 will compress the second return spring 7 in the high gear working oil chamber, so that the shifter shaft 2 is subjected to the spring force generated by the second return spring 7, the spring force is opposite to the force direction of the high gear working oil, the shifter 12 pushes the second shaft sleeve 4 to connect the high gear gear with the sliding sleeve tooth seat on the output shaft, so that the synchronous high-speed power output is realized; when the ECU cuts off the electric signal on the shift electromagnetic valve 11, the high gear working pressure oil flows back to the oil tank through the oil return channel of the shift electromagnetic valve 11, so that the oil pressure applied to the shifter shaft 2 is removed, and then the shifter shaft 2 returns to the intermediate position under the action of the spring force generated by the compressed second return spring 7.

[0052] When the low gear works, the electric signal drives the spool of the shift solenoid valve 11 to move, so that the oil path between the oil inlet and the low gear oil outlet is connected, the pressure oil enters from the oil inlet of the shift solenoid valve 11, and then enters the low gear working oil chamber through the low gear oil outlet, so as to push the shift fork shaft 2 to move to the low gear; during the movement of the shift fork shaft 2 to the low gear, the shaft end face of the shift fork shaft 2 will compress the first return spring 6 in the low gear working oil chamber, so as to be subjected to the spring force generated by the first return spring 6, the spring force is opposite to the force direction of the low gear working oil, the shift fork 12 will push the first shaft sleeve 17 to connect the low gear with the sliding sleeve tooth seat on the output shaft, so as to realize synchronous power output at low speed; when the ECU cuts off the electric signal of the shift solenoid valve 11, the low gear working pressure oil flows back to the oil tank through the return oil channel of the shift solenoid valve 11, so that the oil pressure applied to the shift fork shaft is removed, and then the shift fork shaft 2 returns to the neutral position under the action of the spring force generated by the compressed first return spring 6.

[0053] The intermediate position is between the high gear and the low gear, when the shift fork shaft 2 is in the intermediate position, the shift fork 12 makes the engaging sliding sleeve neither engage with the high gear nor engage with the low gear, so as to realize the neutral position, so that the power take-off device can complete the power take-off operation in the parking state.

[0054] Embodiment

[0055] The embodiment provides a high-low gear hydraulic shift control device suitable for power shift and other engineering machinery, the valve seat 10 is connected with the transmission housing through bolts, the valve seat 10 has two mounting holes, namely a piston seat mounting hole 10-1 and an electromagnetic valve mounting hole 10-2, and the mounting hole 10-1 is provided with an internal thread. The shift solenoid valve 11 is installed in the electromagnetic valve mounting hole 10-2 in a plug-in manner. The valve seat 10 has a first through hole 10-3 and a second through hole 10-4, which are respectively used as a low gear oil inlet oil channel and a high gear oil inlet oil channel.

[0056] The first through hole 10-3 and the second through hole 10-4 vertically penetrate the shift solenoid valve mounting hole 10-2, the first through hole 10-3 penetrates the shift solenoid valve mounting hole 10-2, and the second through hole 10-4 penetrates the shift solenoid valve mounting hole 10-2.

[0057] The piston seat 1 has four circumferentially distributed oil passing holes 1-1, an external thread 1-2 and a sealing ring mounting groove 1-3, and the piston seat 1 is connected with the valve seat 10 through threads. The end face of the piston seat mounting hole 10-1 is provided with a butt joint inclined surface, the fourth O-shaped sealing ring 16 is pressed between the butt joint inclined surface of the valve seat 10 and the first sealing ring mounting groove 1-3 of the piston seat 1, so as to ensure the sealing property between the two.

[0058] The spacer ring 5 has four circumferentially distributed oil passage slits 5-1 and a second sealing ring mounting groove 5-2. For example... Figure 8 As shown, the spacer ring 5 is installed in the valve seat 10, and the second O-ring seal 14 is squeezed between the piston seat mounting hole 10-1 and the second sealing ring mounting groove 5-2 to ensure that there is no oil leakage or cross-flow between the high and low working oil chambers on both sides of the fourth O-ring seal 16.

[0059] The first through hole 10-3 of the valve seat 10, the oil passage hole 1-1 of the piston seat 1, and the oil passage cut 5-1 on the outer wall of the spacer ring form a low-gear oil passage. When a low-gear working command is issued, the low-gear pressure oil enters the low-gear working oil chamber through the shift solenoid valve, as shown in the following path... Figure 1 As shown.

[0060] A high-gear oil passage is formed between the second through hole 10-4 of the valve seat 10 and the spacer ring 5. When a high-gear working command is issued, the high-gear pressure oil enters the high-gear working oil chamber through the shift solenoid valve via the following path: Figure 2 As shown.

[0061] The high and low gear shifting device uses a shifting solenoid valve that can achieve six working modes through different electrical signals: switching between high and low gears, switching between high gear and neutral, and switching between low gear and neutral.

[0062] like Figure 3 As shown, when the electrical signal is cut off (i.e., the electrical signal is 0), the shift solenoid valve does not supply oil, and the shift fork shaft 2 is stabilized in the intermediate position by the spring force of the first return spring 6 and the second return spring 7. The power transmitted from the intermediate shaft to the auxiliary gearbox output shaft is cut off, realizing neutral.

[0063] like Figure 9 As shown, the two self-locking steel balls 8 feed back the gear position signal to the ECU through three position states: one low and one high, one high and one low, and both low.

[0064] like Figure 1 , 2 As shown, the spring washer 3 and the bottom of the inner cavity of the piston seat 1 serve as low and high gear limiters to prevent the shift fork from impacting the high / low gear.

[0065] The invention is simple and clear in logic and easy to implement. The parts involved, such as the shift solenoid valve, shift fork shaft, valve seat, piston seat, spacer ring, and return spring, can be integrated into an independent assembly, which makes it convenient to install on the transmission housing.

[0066] In summary, this invention provides a shifting assembly and method with return springs on both high and low gear sides. The valve seat has two parallel mounting holes: one for mounting the shifting solenoid valve and the other for mounting components such as the shift fork shaft, spacer ring, return spring, and piston seat. This design makes the high and low gear shifting device compact, highly integrated, space-saving, and easy to install and disassemble. Furthermore, the control logic is simple and easy to understand, offering great versatility.

[0067] The valve seat is fixed to the transmission housing by bolt holes, while the oil inlet end of the parallel shift solenoid valve mounting hole is directly connected to the housing, reducing unnecessary leakage and pressure loss caused by oil pipes or oil passages.

[0068] The shift solenoid valve used in the high / low gear shifting device is connected to the valve seat via an integral cartridge mounting method, reducing the relative movement between parts and the valve block and the amount of assembly work, effectively reducing the risk of oil leakage. The piston seat and valve seat are connected by threads, and the shift fork shaft, spacer ring, return spring, spring washer, and bushing are all placed in the mounting cavity formed between the piston seat and valve seat. The installation method is simple and easy to operate, facilitating the maintenance and replacement of parts, and effectively reducing manufacturing costs and installation and maintenance difficulty.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A shift assembly with high and low range side band return springs, characterized by, The piston seat (1), the shift fork shaft (2), the spacer ring (5), the first return spring (6), the second return spring (7), the valve seat (10), the shift electromagnetic valve (11) and the shift fork (12) are included; the piston seat mounting hole (10-1) and the shift electromagnetic valve mounting hole (10-2) are arranged in the valve seat (10), and the first through hole (10-3) and the second through hole (10-4) are arranged in parallel between the piston seat mounting hole (10-1) and the shift electromagnetic valve mounting hole (10-2); the mounting end of the piston seat (1) is assembled in the piston seat mounting hole (10-1), the oil supply end of the shift electromagnetic valve (11) is assembled in the shift electromagnetic valve mounting hole (10-2), and the oil supply end of the shift electromagnetic valve (11) is communicated with the first through hole (10-3) and the second through hole (10-4) respectively; the spacer ring (5) is assembled in the piston seat (1), and the internal space of the piston seat (1) is divided and arranged, wherein the first through hole (10-3) of the valve seat (10) and the outer wall of the spacer ring (5) and the inner wall of the piston seat (1) form a low gear working oil cavity; the second through hole (10-4) of the valve seat (10) and the inner wall of the spacer ring (5) form a high gear working oil cavity; one end of the shift fork shaft (2) extends into the piston seat (1) through the valve seat (10) and the spacer ring (5) in sequence, the first return spring (6) is sleeved on the shift fork shaft (2) in the low gear working oil cavity, and the second return spring (7) is sleeved on the shift fork shaft (2) in the high gear working oil cavity, and the other end of the shift fork shaft (2) is assembled with the shift fork (12); The mounting end of the piston seat (1) is provided with an external thread (1-2) and a first sealing ring mounting groove (1-3), the external thread (1-2) is assembled in the piston seat mounting hole (10-1), and the third O-shaped sealing ring (15) is sleeved between the first sealing ring mounting groove (1-3) and the inner wall of the piston seat mounting hole (10-1); a plurality of oil passing holes (1-1) are annularly arranged on the mounting end of the piston seat (1), the oil passing holes (1-1) are communicated with the first through hole (10-3) and the outer wall of the spacer ring (5) to form a low gear working oil passage; The shift fork shaft (2) is sleeved with the first shaft sleeve (17) in the low gear working oil cavity, one end of the first return spring (6) is sleeved in the first shaft sleeve (17), and the other end is fixed at the inner wall end of the piston seat (1); The spring washer (3) is arranged at the inner wall end of the piston seat (1) in the high gear working oil cavity, the shift fork shaft (2) is sleeved with the second shaft sleeve (4) in the high gear working oil cavity, one end of the second return spring is sleeved on the second shaft sleeve (4), and the other end is fixed at the spring washer (3).

2. The shift assembly with high and low side band return spring of claim 1, wherein, The spacer ring (5) is provided with a through hole, the shift fork shaft (2) penetrates through the through hole, one end of the spacer ring (5) is provided with a plurality of oil passing notches (5-1) along the radial direction, one end of the oil passing notches (5-1) is communicated with the oil passing hole (1-1) and the first through hole (10-3) in sequence, the other end is communicated into the piston seat (1) to form a low gear working oil channel; the other end of the spacer ring (5) is annularly provided with a second sealing ring mounting groove (5-2), the second O-shaped sealing ring (14) is sleeved between the second sealing ring mounting groove (5-2) and the inner wall of the piston seat mounting hole (10-1).

3. The shift assembly of claim 1, wherein, Further comprising two self-locking steel balls (8), the two self-locking steel balls (8) are slidingly arranged on the shift fork shaft (2) outside the piston seat (1), wherein the shift fork shaft (2) is provided with two self-locking grooves on the outer end of the piston seat (1), and the two steel balls (8) are slidingly arranged on the two self-locking grooves along the movement direction of the shift fork shaft (2).

4. The shift assembly of claim 1, wherein, The first O-shaped sealing ring (13) is sleeved between the shift fork shaft (2) and the piston seat (1), and the fourth O-shaped sealing ring (16) is sleeved between the shift fork shaft (2) and the spacer ring (5).

5. The shift assembly of claim 1, wherein, The shift fork shaft (2) is provided with a groove (9) at the end of the assembled shift fork (12), and the shift fork (12) is fixed on the shift fork shaft (2) by being inserted into the groove (9) through a bolt.

6. The shift assembly of claim 1, wherein, The shift electromagnetic valve (11) is a three-position four-way electromagnetic switch valve, comprising an oil inlet, an oil return, a high gear oil outlet and a low gear oil outlet, the high gear oil outlet is communicated with the second through hole (10-4), the low gear oil outlet is communicated with the first through hole (10-3), one end of the oil inlet is communicated with the high gear oil outlet and the low gear oil outlet respectively, the other end is connected with a pressure oil output device, the oil return is connected with the high gear oil outlet and the low gear oil outlet respectively, and the other end is connected with an oil return tank.

7. A shift method of a shift assembly with high and low range side band return springs, based on the shift assembly with high and low range side band return springs according to any one of claims 1-6, characterized in that, The process comprises the following steps: When the high gear works, the electric signal drives the valve core of the shift electromagnetic valve (11) to move, so that the oil path between the oil inlet and the high gear oil outlet is conducted, the pressure oil enters from the oil inlet of the shift electromagnetic valve (11), enters the high gear working oil chamber through the high gear oil outlet, and pushes the shift fork shaft (2) to move to the high gear; during the movement of the shift fork shaft (2) to the high gear, the shaft end face of the shift fork shaft (2) will compress the second return spring (7) in the high gear working oil chamber, so as to be subjected to the spring force generated by the second return spring (7), the spring force is opposite to the force direction of the high gear working oil, the shift fork (12) will push the second shaft sleeve (4) to connect the high gear gear with the sliding sleeve tooth seat on the output shaft, so as to realize synchronous high speed power output; when the ECU cuts off the electric signal on the shift electromagnetic valve (11), the high gear working pressure oil flows back to the oil tank through the oil return channel of the shift electromagnetic valve (11), so that the oil pressure applied to the shift fork shaft (2) is removed, and then the shift fork shaft (2) returns to the middle position under the action of the spring force generated by the compressed second return spring (7); When the low gear works, the electric signal drives the spool of the shift solenoid valve (11) to move, so that the oil path between the oil inlet and the low gear oil outlet is open, the pressure oil enters from the oil inlet of the shift solenoid valve (11), and then enters the low gear working oil cavity through the low gear oil outlet, so as to push the shift fork shaft (2) to move to the low gear; during the movement of the shift fork shaft (2) to the low gear, the shaft end face of the shift fork shaft (2) will compress the first return spring (6) in the low gear working oil cavity, so as to be subjected to the spring force generated by the first return spring (6), the spring force is opposite to the force direction of the low gear working oil, the shift fork (12) will push the first shaft sleeve (17) to connect the low gear with the sliding sleeve tooth seat on the output shaft, so as to realize synchronous power output at low speed; when the ECU cuts off the electric signal of the shift solenoid valve (11), the low gear working pressure oil flows back to the oil tank through the oil return channel of the shift solenoid valve (11), so that the oil pressure applied to the shift fork shaft is removed, and then the shift fork shaft (2) returns to the intermediate position under the action of the spring force generated by the compressed first return spring (6); The intermediate position is between the high gear and the low gear, when the shift fork shaft (2) is located at the intermediate position, the shift fork (12) makes the engaging sliding sleeve neither engage with the high gear nor engage with the low gear, so as to realize the neutral position, so that the power take-off device can complete the power take-off operation in the parking state.

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