A gear shift piston cylinder system and fault detection method thereof

Abstract

The present invention relates to a shift piston cylinder system and a fault detection method thereof. Specifically, the characteristic that there is a corresponding shift displacement difference between the mechanical dead position of the corresponding gear position of the shift mechanism and the positioning structure of the pneumatic mechanism (or other mechanism that uses fluid to transmit pressure) is utilized. First, pressure is established in the chamber of the corresponding gear position so that the pneumatic mechanism reaches the mechanical dead position of the shift mechanism. At this time, the corresponding valve body is closed. If the corresponding air path, chamber and electromagnetic valve have good sealing performance, the pneumatic mechanism will not be displaced under the action of pressure. Otherwise, the positioning force of the positioning structure of the pneumatic mechanism will push the relevant components back to the positioning position of the gear position, that is, the normal working position. Utilizing this characteristic, a fault detection method is established to solve the problem of difficulty in fault diagnosis of electromagnetic valve mechanical faults and fault identification of sealing faults such as cylinder seals, thereby improving maintenance efficiency.

Description

Technical Field

[0001] The invention relates to a shift piston cylinder system and a fault detection method thereof, belonging to the technical field of AMT transmission control. Background Art

[0002] With the development of pure electric technology, electric drive systems are increasingly using gearboxes to meet the needs of power. AMT gearboxes use piston cylinders to drive the shift system's moving parts to achieve shifting, which has the advantages of high reliability, long life, and low cost.

[0003] The AMT gearbox currently used in pure electric mining cars has three gears. Correspondingly, the piston rod in its piston cylinder system also has three working positions. The three-position piston cylinder has two left and right chambers, and three control methods: pressurizing the two chambers separately and pressurizing the two chambers at the same time. A group of piston groups with different force surfaces are used to realize the stop of the piston rod in three working positions.

[0004] Due to the harsh working conditions of mine cars and the high dust content in the air, the reliability of the AMT gearbox shift cylinder is greatly challenged. Faults such as dust and sand entering the cylinder causing wear and tear, which in turn leads to cylinder leakage and ultimately difficulty in shifting, often occur. Manual inspection and elimination of each component failure are required one by one to identify the cause of the problem and find the faulty cylinder chamber. The maintenance efficiency is low, affecting vehicle operations.

[0005] In the prior art, the fault diagnosis scheme of the piston cylinder system is mainly aimed at the fault diagnosis of the solenoid valve circuit system. The circuit fault of the solenoid valve can be determined by collecting the voltage, current, resistance and other parameters of the solenoid valve circuit system. For non-circuit faults of the solenoid valve, the inspection needs to add sensors of related media (pressure, temperature, etc.); for example, in the Chinese patent publication with publication number CN110146757A, sensors are used to collect pressure changes to determine solenoid valve jams and air leakage faults, but the working conditions of the mine car are harsh, the piston cylinder structure is complex, and the pressure of the pressure source (the gas cylinder commonly used in mine cars) is constantly changing during the operation of the whole vehicle. The gas pressure fluctuates greatly during the shifting process. Therefore, this solution is not suitable for the pneumatic AMT system of the mine car, and adding pressure sensors will also increase the risk of component failure; and in the Chinese patent authorization text with publication number CN105604663B, a temperature sensor is used to determine the temperature change of the medium to diagnose the solenoid valve fault, which is not suitable for cylinders using air as the medium in the piston cylinder; the Chinese patent publication texts with publication numbers CN108267658A and CN109917205A are mainly for the diagnosis of solenoid valve circuit faults, and non-circuit faults cannot be detected and diagnosed. Summary of the invention

[0006] The object of the present invention is to provide a shift piston cylinder system and a fault detection method thereof, so as to solve the problem that it is difficult to quickly find the cause and location of a pneumatic AMT system in a shift fault.

[0007] To achieve the above object, the solution of the present invention includes:

[0008] A shifting piston cylinder system of the present invention comprises a shifting mechanism, a piston cylinder driving the shifting mechanism, a piston cylinder driving unit and a controller connected to the piston cylinder driving unit;

[0009] The piston cylinder comprises: a piston rod connected to the shift mechanism, a cylinder body, a piston system, a positioning device and a position sensor for detecting the position of the piston system or the piston rod; the cylinder body is divided into at least two chambers by the piston system; the positioning device will apply force to force the piston system or the piston rod to stay at the position corresponding to the current gear position after entering the corresponding gear position;

[0010] When the piston system is driven to move, the shift mechanism can reach the gear dead point of the corresponding gear by pushing the piston rod. After the driving force is removed, the piston system or the piston rod can return to the gear position of the corresponding gear under the action of the positioning device; the gear dead point is the maximum point reached by the moving parts in the shift mechanism at the corresponding gear.

[0011] The piston cylinder drive unit includes: a pressure source and a valve; the pressure source can be connected to the chamber to input a fluid of a certain pressure into the corresponding chamber; the valve is controlled by the controller to control the connection and disconnection of the fluid channel from the pressure source to the corresponding chamber, and the pressure relief of the corresponding chamber;

[0012] The controller executes the instructions to implement the following sealing performance detection method for the corresponding chamber:

[0013] 1) Introduce a pressurized fluid into a chamber;

[0014] 2) When the position sensor detects that the piston system or the piston rod reaches the displacement of the gear dead point of the corresponding gear, the fluid channel of the corresponding chamber is closed;

[0015] 3) If the position sensor detects a change in the position of the piston system or the piston rod within the set time after shutdown, it means that there is a leakage fault in the corresponding chamber; if the position sensor does not detect a change in the position of the piston system or the piston rod, it means that the sealing of the corresponding chamber is good.

[0016] The present invention utilizes the characteristic that there is a corresponding shift displacement difference between the mechanical dead position of the corresponding gear of the shift mechanism and the positioning structure of the pneumatic mechanism (or other mechanism that uses fluid to transmit pressure). First, pressure is established in the chamber of the corresponding gear to make the pneumatic mechanism reach the mechanical dead position of the shift mechanism. At this time, the corresponding valve body is closed. If the corresponding air path, chamber and solenoid valve have good sealing performance, the pneumatic mechanism will not be displaced under the action of pressure. Otherwise, the positioning force of the positioning structure of the pneumatic mechanism will push the relevant components back to the positioning position of the gear, that is, the normal working position. Utilizing this characteristic, a fault detection method is established to solve the problem of difficulty in fault diagnosis of mechanical faults of solenoid valves and fault identification of sealing faults such as cylinder seals, thereby improving maintenance efficiency.

[0017] Furthermore, in step 3), the position of the piston system or the piston rod changes as follows: the piston system or the piston rod changes from a displacement corresponding to the gear dead point of the corresponding gear to a displacement corresponding to the gear positioning.

[0018] In order to further improve the detection accuracy, if there is a leakage fault, the displacement of the pneumatic mechanism under the action of the positioning force should return to the positioning position. If only displacement occurs but not returning to the positioning position, it is not a problem caused by poor sealing.

[0019] Furthermore, the gear dead point of the corresponding gear is determined by the stop structure of the gear shift mechanism at the corresponding gear, and the gear positioning of the corresponding gear is determined by the positioning device of the piston cylinder.

[0020] Further, the piston rod moves left and right along the set axis and has three set positions of left, middle and right, which correspond to the 1st gear, neutral gear and 2nd gear of the shift mechanism respectively; corresponding to the 1st gear and the 2nd gear, the shift mechanism includes a stop structure that determines the dead point of the gear position; corresponding to the 1st gear, the 2nd gear and the neutral gear, the positioning device includes a positioning structure that determines the positioning of the gear position;

[0021] The piston system includes a first piston, a second piston, and a third piston; the first piston and the second piston are fixed to the piston rod; the cylinder body includes a first chamber and a second chamber distributed on the left and right;

[0022] The first piston comprises a first force-bearing surface for being subjected to rightward pressure by the medium in the first chamber, and the first piston is slidably assembled in the first chamber;

[0023] The second piston comprises a second force-bearing surface for being exerted with leftward pressure by the medium in the second chamber;

[0024] The third piston includes a third force-bearing surface, which is used to be exerted with a leftward pressure by the medium in the second chamber; a limiting structure is provided on the third piston, and a blocking structure is provided in the cylinder body, and the limiting structure is used to cooperate with the blocking structure in the cylinder body so that the third piston is blocked from moving to the left; the third piston moves left and right, and has a left limit position and a right limit position; the third piston is a sleeve structure, and the piston rod and the second piston are inserted into the sleeve hole to the right, and the second piston is sealed and slidably matched with the sleeve hole; the third piston includes a left-side plug-in sleeve and a right-side ring platform, and the plug-in sleeve is inserted into the first chamber to the left, and a push structure is provided on the plug-in sleeve, which is used to push the first piston to the left or to be pushed to the right by the first piston to drive the third piston to move to the right limit position; the outer peripheral surface of the ring platform is slidably and sealedly matched with the second chamber; when the limiting structure cooperates with the blocking structure, the third piston is in the left limit position and corresponds to the middle position or left position of the piston rod; when the piston rod is in the right position, the corresponding third piston is in the right limit position;

[0025] The area of ​​the first force-bearing surface is larger than that of the second force-bearing surface, and the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface; the volume of the second chamber is larger than that of the first chamber.

[0026] The shift piston cylinder system of the present invention can realize the neutral gear return operation by simultaneously introducing pressure medium into two chambers, has a simple and reliable structure and is easy to drive to realize the shift operation.

[0027] Furthermore, the shift piston cylinder system according to claim 4 is characterized in that the positioning device includes a positioning spring, a positioning steel ball and a positioning groove arranged on the piston rod corresponding to each gear position, and the positioning groove is a trumpet-shaped opening; the positioning steel ball drives the piston rod to move axially under the action of the elastic force of the positioning spring so that the positioning steel ball stays at the center position of the trumpet-shaped opening of the positioning groove; the distance on the piston rod from the center position of the positioning groove corresponding to the neutral gear to the center position of the positioning groove corresponding to the 1st gear or the 2nd gear is smaller than the displacement distance of the piston rod from the neutral gear position to the gear dead point corresponding to the 1st gear or the 2nd gear.

[0028] The gear positioning is achieved by positioning the steel ball, the structure is simple and reliable, easy to maintain and low cost.

[0029] Furthermore, the right side of the ring platform of the third piston has an annular end face, which is used to be pressed to the left by the medium in the second chamber to form the third force-bearing surface; the cross-sectional area of ​​the first chamber is smaller than that of the second chamber, and a first step is formed between the first chamber and the second chamber; the outer diameter of the sleeve is smaller than the outer diameter of the ring platform, and a second step is formed between the sleeve and the ring platform, and the left end face of the second step is used to cooperate with the right end face of the first step; the second step forms a limiting structure of the third piston, and the first step forms a blocking structure in the cylinder body.

[0030] Further, the valve includes a first controlled valve, a second controlled valve and a third controlled valve, the first and second controlled valves are both two-position three-way valves, and the third controlled valve is a two-position two-way valve; when the first and second controlled valves are in the first valve position, the first controlled valve is connected to the pressure relief port and the first chamber, and the second controlled valve is connected to the pressure relief port and the second chamber; when the first and second controlled valves are in the second valve position, the first controlled valve is connected to the outlet of the third controlled valve and the first chamber, and the second controlled valve is connected to the outlet of the third controlled valve and the second chamber; when the third controlled valve is in the first valve position, the pressure source outlet and the third controlled valve outlet are sealed; when the third controlled valve is in the second valve position, the pressure source outlet and the third controlled valve outlet are connected.

[0031] Furthermore, before step 1), the following preliminary tests are performed:

[0032] a) introducing pressurized fluid into the first chamber and the second chamber simultaneously;

[0033] b) If the position sensor detects that the position of the piston system or the piston rod is biased towards the 1st gear, the sealing performance test of the first chamber is performed; if the position sensor detects that the position of the piston system or the piston rod is biased towards the 2nd gear, the sealing performance test of the second chamber is performed.

[0034] In the control of piston cylinders, if the piston rod cannot be accurately positioned, it can often comprehensively reflect the changes in the comprehensive performance parameters of the two chambers of the piston cylinder, such as the resistance of piston movement, the sealing of the chamber, etc. The return to the center position control requires the two chambers to build up pressure at the same time, and the pressure difference is used to generate the driving force to move the piston rod. Therefore, the difficulty in returning to the center position can reflect some minor performance changes in the early stage of the fault risk, such as the reduction of sealing performance (the control of the piston rod to the two dead points only requires one chamber to build up pressure, and the pressure difference is large. Even if the piston resistance is large or even stuck, it can be overcome under a large thrust. Once the left and right workstations are difficult to reach, it is often a serious fault in the piston cylinder, and the early warning of the fault risk cannot be achieved); therefore, if the piston rod is difficult to return to the center position, it can serve as an early warning of the fault, reminding you to conduct a timely sealing inspection to eliminate the fault in an early state.

[0035] Therefore, before the sealing performance test, the present invention can also perform a preliminary test on whether there is a fault. The preliminary test can determine whether the shift mechanism is normal. If it is abnormal, it can also predict the faulty chamber (possible leakage), providing a test basis and foundation for the next step of the sealing performance test of the present invention.

[0036] At the same time, the preliminary inspection process is the same as the control method of putting the transmission in neutral gear. Preliminary inspection can be carried out during vehicle operation, which helps to find problems immediately.

[0037] Furthermore, in step 2), if the position sensor does not detect the displacement of the piston system or the piston rod reaching the gear dead point of the corresponding gear, a fault of the two-position three-way valve of the corresponding chamber is reported.

[0038] When a single chamber builds up pressure, the piston is subjected to the greatest force and should easily reach one end to complete the corresponding gear shift. If the gear shift is not achieved at this time, there is a high probability that the corresponding valve body has a fault, resulting in the inability of the corresponding chamber to build up effective pressure to push the piston and related components to move. In addition to testing the sealing performance, the fault detection method of this invention can also detect valve faults, thereby improving the detection efficiency.

[0039] A shift piston cylinder fault detection method of the present invention adopts the sealing performance detection method in the shift piston cylinder system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the piston cylinder system of the present invention;

[0041] Figure 2 It is a control principle diagram of the piston cylinder system of the present invention;

[0042] Figure 3 yes Figure 1 A simplified schematic diagram showing the piston rod in the piston cylinder in the left position;

[0043] Figure 4 yes Figure 1 A simplified schematic diagram showing a piston rod in a piston cylinder in a neutral position;

[0044] Figure 5 yes Figure 1 A simplified schematic diagram showing the piston rod in the piston cylinder in the right position;

[0045] Figure 6 It is a structural schematic diagram of another embodiment of a piston cylinder;

[0046] Figure 7 It is a flow chart of a control method for a shift system driven by a piston cylinder system of the present invention to perform a shift control;

[0047] Figure 8 It is a schematic diagram of the position of the shift positioning steel ball of the shift system driven by the piston cylinder system of the present invention in the second gear (after the first solenoid valve is powered off and the first chamber is depressurized);

[0048] Fig. 9 It is a schematic diagram of the position and force analysis of the shift positioning steel ball of the shift system driven by the piston cylinder system of the present invention in the second gear (before the first solenoid valve is powered off and before the first chamber is depressurized);

[0049] Fig.10It is a flow chart of a method for detecting a shift cylinder leakage fault in a parking state.

[0050] In the figure: 10-air source; 2-piston drive unit; 21-third solenoid valve; 22-first solenoid valve; 23-second solenoid valve; 33-displacement sensor; 4-piston cylinder; 41-cylinder body; 410-first step; 42-piston; 421-first piston; 422-second piston; 423-third piston; 4230-second step; 4231-ring platform; 4232-sleeve; 43-first chamber; 44-second chamber; 45-piston rod; 451-positioning groove; 46-positioning device; 461-shift positioning steel ball; 462-spring; 51-piston cylinder controller; 52-bus. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0052] Shift piston cylinder system embodiment:

[0053] The shift piston cylinder system of this embodiment is applicable to the shift piston cylinder fault detection method of the present invention.

[0054] The piston cylinder system and the piston cylinder of the present invention are applied to an embodiment of a 2-speed AMT shift system, and are used to drive the shift actuator of the vehicle AMT (automatic transmission) to complete the shift action. The AMT includes a shift actuator and a piston cylinder system. The shift controller of the automatic transmission can have the function of a cylinder controller, or an independent cylinder controller can be used, which is controlled and connected by the shift controller. The piston rod of the piston cylinder is connected to the shift actuator, and the shift controller or the independent cylinder controller (such as Figure 2 As shown, the piston cylinder controller 51) samples the piston cylinder in the piston cylinder system and the sensors on the piston cylinder drive unit (such as Figure 2 As shown, it is mainly a displacement sensor 33), and also controls the fluid control element (such as Figure 2 As shown, the third solenoid valve 21, the first solenoid valve 22 and the second solenoid valve 23).

[0055] Piston cylinder system Figure 1 , Figure 2As shown, it includes a piston cylinder 4, a piston cylinder driving unit 2, and a piston cylinder controller 51. The piston cylinder 4 is used to provide a linear displacement driving force to the shift actuator of the vehicle's AMT (automatic transmission). The linear displacement of the output end of the piston cylinder 4 directly corresponds to the gear change of the shift actuator. The mechanical structure of the shift actuator and the transmission structure of the output end of the piston cylinder belong to the prior art and are not the improved content of the present invention. The improvement of the present invention mainly involves the structure of the piston cylinder and how to control the linear displacement output by the piston cylinder. The piston cylinder applicable to the present invention can be a hydraulic cylinder or a pneumatic cylinder, that is, a fluid power cylinder applicable to all basic principles of inputting corresponding fluid through an external pressure source, establishing pressure in the piston cylinder chamber, and then driving the piston to move. In this embodiment, a pneumatic piston cylinder (hereinafter referred to as a cylinder) is used as an example to illustrate the present invention.

[0056] like Figure 1 , Figure 3 to Figure 5 As shown, the piston cylinder 4 in this embodiment is a gas cylinder, comprising: a cylinder body 41, a piston rod 45, a positioning device 46, a first piston third solenoid valve 1, a second piston 422, and a third piston 423. The cylinder body 41 has a chamber on the left and right, respectively, a first chamber 43 and a second chamber 44, the cross-sectional area of ​​the first chamber 43 is smaller than that of the second chamber 44, and a first step 410 is formed between the first chamber 43 and the second chamber 44, and the first step 410 is a transition step.

[0057] The first piston 421 and the second piston 422 are fixedly connected to the piston rod 45, and the first piston 421, the second piston 422 and the piston rod 45 move synchronously. The outer peripheral surface of the first piston 421 is in sealing and sliding cooperation with the first chamber 43, and the left end surface of the first piston 421 is used to be pressed to the right by the medium in the first chamber, forming the first force-bearing surface of the first piston 421.

[0058] The third piston 423 is a sleeve structure, and has a sleeve hole inside. The piston rod 45 and the second piston 422 are inserted into the sleeve hole to the right. The second piston 422 and the sleeve hole of the third piston 423 are sealed and slidably matched. The right end surface of the second piston 422 is used to be pressed to the left by the medium in the second chamber, forming a second force-bearing surface of the second piston 422.

[0059] The third piston 423 has a left-side plug sleeve 4232 and a right-side ring platform 4231 on the outside. The outer diameter of the plug sleeve 4232 is smaller than the outer diameter of the ring platform 4231, and a second step 4230 is formed between the two. The left end face of the second step 4230 is used to stop and cooperate with the right end face of the first step 410 in the cylinder body 41, so that the second step 4230 forms a limiting structure on the sliding path of the third piston 423, which is used to limit the leftward movement of the third piston. Correspondingly, the first step 410 forms a blocking structure in the cylinder body 41. The existence of the blocking structure enables the third piston to have a left limit position for moving to the left. The plug sleeve 4232 is inserted into the first chamber 43 to the left, and the left end face of the plug sleeve 4232 is used to push and cooperate with the first piston 421 to the left, forming a push structure of the third piston 423. When the first piston 421 moves to the right, it can push the third piston 423 to move to the right. The existence of the push structure enables the third piston to have a right limit position for moving to the right. The outer peripheral surface of the annular platform 4231 is in sliding sealing cooperation with the second chamber 44. The right side of the third piston 423 has an annular end surface, which is used to be pressed to the left by the medium in the second chamber, forming a third force-bearing surface of the third piston 423. Due to the existence of the pushing structure of the above-mentioned third piston 423, when the third piston moves to the left, it can push the first piston 421 to move to the left.

[0060] In order to realize the piston rod 45 having three set positions of left, middle and right in the left and right direction of movement, the force-bearing surfaces of the first, second and third pistons are set as follows: the area of ​​the first force-bearing surface is larger than the area of ​​the second force-bearing surface; the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface, and due to the power transmission effect of the push structure of the third piston 423, the blocking structure (first step 410) of the cylinder body 41 and the limiting structure (second step 4230) on the third piston 423, the piston rod 45 can move left and right and stay at the left, middle and right positions. Specifically, the piston-cylinder driving unit 2 only inputs gas into the first chamber 43 to provide pressure, which can build up pressure in the first chamber 43, pushing the first piston 421 to drive the piston rod 45 and the second piston 422 to move rightward to the right position; or the piston-cylinder driving unit 2 only inputs gas into the second chamber 44 to build up pressure, the second piston 422 pushes the first piston 421 and the piston rod 45 to move leftward to the left position, and the third piston 423 is blocked by the blocking structure of the cylinder body 41 and is in its left limit position; and when the first and second chambers both input gas of the same pressure, although the third piston 423 and the second piston 422 can provide a driving force greater than the first piston 421 (the area of ​​the first force-bearing surface is smaller than that of the second force-bearing surface and the third piston 423), the third piston 423 and the second piston 422 can provide a driving force greater than that of the first piston 421 (the area of ​​the first force-bearing surface is smaller than that of the second force-bearing surface and the third piston 423). The sum of the areas of the three force-bearing surfaces), but because the second piston 422 itself cannot push the first piston 421 to move to the left (the area of ​​the first force-bearing surface is larger than the area of ​​the second force-bearing surface), and the third piston 423 is blocked at its left limit position and cannot continue to push the first piston 42, the piston rod 45 can stay in the middle position between the left position and the right position; conversely, although the first piston 421 itself can push the second piston 422 to move to the right (in the process of moving from the left position to the middle position), but in the middle position, the first piston 421 will be blocked by the pushing structure of the third piston 422, and cannot continue to push the second piston 422 to the right (the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second and third force-bearing surfaces).

[0061] In addition, the piston rod 45 is provided with three positioning grooves 451 at the left, middle and right positions. Correspondingly, the positioning device 46 includes a spring 462 and a shift positioning steel ball 461 elastically pressed by the spring 462. The shift positioning steel ball of the positioning device 46 cooperates with the left, middle and right positioning grooves on the piston rod 45 to limit the moving position of the piston rod 45, so as to prevent the tilt, vibration, acceleration and the like generated during vehicle operation from causing the piston rod to shift, resulting in gear changes or even damage to the shift mechanism.

[0062] The three positions of the piston rod 45 on the travel correspond to the 1st gear, neutral gear, and 2nd gear of the AMT. It should be noted that the "left and right" defined in the application document of the present invention refers to the relative position relationship in the linear displacement direction of the piston cylinder output, and "center" refers to the position between the left and right, not the absolute left and right. In other words, when the piston cylinder is placed vertically, although the piston rod can be considered to move up and down, the relative position relationship between the left and right in the piston cylinder still exists at this time, and it cannot be considered that the left and right relationship is changed to absolute up and down.

[0063] A displacement sensor 33 is also provided on the cylinder wall of the second chamber 44 opposite to the movement direction of the piston rod 45, which may be an ultrasonic distance sensor or an infrared distance sensor. The displacement sensor 33 is used to detect the position of the piston rod 45 during the operation of the piston cylinder. The displacement of the piston rod can be obtained by performing two detections. The displacement of the piston rod may be, for example, Figure 1 In the figure, the distance from the right end of the piston rod 45 in the second chamber 44 to the displacement sensor 33; as other embodiments, the position of the first piston 421 can also be detected in the first chamber 43, or the position of the second piston 422 can be detected, or the displacement of the piston rod 45 can be detected by an external displacement sensor to obtain the position of the piston rod 45.

[0064] The piston cylinder driving unit includes an air source 10, a third solenoid valve 21, a first solenoid valve 22 and a second solenoid valve 23. The first solenoid valve 22 and the second solenoid valve 23 are respectively connected and arranged on the first chamber 43 and the second chamber 44. The first chamber 43 of the piston cylinder is connected to the first solenoid valve 22, and the second chamber 44 is connected to the second solenoid valve 23. The first solenoid valve 22 and the second solenoid valve 23 are both two-position three-way normally closed solenoid valves, that is, when the solenoid valve is powered on and opened, the cylinder chamber is connected to the air source of the air circuit, and when the solenoid valve is closed, the cylinder chamber is connected to the atmosphere. The other ends of the first solenoid valve 22 and the second solenoid valve 23 are connected to the outlet of the third solenoid valve 21 through the air path 24, and the inlet of the third solenoid valve 21 is connected to the electrical pressure source 10. In this embodiment, the third solenoid valve is a two-position, two-position normally open solenoid valve, that is, it is a passage when it is not powered on, ensuring that the air path from the air pressure source 10 to the first solenoid valve 22 and the second solenoid valve 23 on the two chambers is unobstructed. The third solenoid valve 21 is closed when powered on, so that the corresponding air path is airtightly blocked. The air pressure source 10 can be specifically an air pump or a gas storage bottle. In this embodiment, the first solenoid valve 22 and the second solenoid valve 23 are both intake valves and exhaust pressure relief valves. Of course, the pressure relief of the cylinder chamber can also be achieved through other separate valves.

[0065] Specific signal and control principle diagram as follows Figure 2As shown, the cylinder controller 51 is connected to the bus 52, and the third solenoid valve 21, the first solenoid valve 22, the second solenoid valve 23, and the displacement sensor 33 are sequentially connected to the bus 52, and the collected piston rod position data is uploaded or the corresponding control instructions are received through the bus; as other embodiments, the controller 51 can also control or collect the connected electric control valves and sensors in sequence through a single line.

[0066] The working process of the 2-speed AMT shift system using a shift cylinder is as follows:

[0067] The AMT transmission mechanism has three gear positions: 1st gear, 2nd gear (in specific applications, it can be high speed gear and climbing gear) and neutral gear. As for the piston cylinder of the above-mentioned driving shift actuator, the piston rod 45 also has three corresponding left, middle and right positions, which can be limited by the shift positioning steel ball of the positioning device 46 and the positioning groove. The specific gear positions are as follows Figures 3 to 5 As shown, Figure 4 In the middle, the piston rod 45 is in the middle position of the full stroke, which is the neutral position; Figure 3 In the middle, the piston rod 45 is at the left position of the full stroke, which is the 1st gear position; Figure 5 In the figure, the piston rod 45 is at the right position of the full stroke, which is the 2nd gear position; the shifting process can be divided into four processes: shifting from neutral to 1st gear, shifting from neutral to 2nd gear, shifting from 1st gear to neutral, and shifting from 2nd gear to neutral. The basic working principles of each shifting process are introduced below.

[0068] 1) Neutral gear to 1st gear: Figure 1 , Figure 3 , Figure 4 As shown, the second solenoid valve 23 is opened, the second chamber 44 is connected to the high-pressure gas source as an air inlet chamber, and the high-pressure gas is introduced. The first solenoid valve 22 is closed, and the first chamber 43 is connected to the atmosphere; after the second chamber 44 builds up air pressure, it pushes the second piston 422 and the piston rod 45 to move leftward, and the displacement sensor 33 feeds back the displacement of the piston rod in real time (the displacement can reflect the shifting process), so as to achieve the above-mentioned operation. Figure 4 Neutral position to Figure 3 The gear shifting process control in the middle 1st gear position. In the control of the whole gear shifting process, it is necessary to first establish the corresponding air pressure to overcome the elastic force of the spring in the positioning device 46, so that the gear shift positioning steel ball is disengaged from the positioning groove corresponding to the current gear position (i.e., the positioning groove of the neutral gear), and then establish the air pressure to push the corresponding gear shift actuator (including the shift fork, the synchronous tooth, the coupling tooth, etc.) to complete the gear shifting, until the gear shift positioning steel ball enters the positioning groove corresponding to the 1st gear, and the gear is completed.

[0069] 2) 1st gear to neutral gear: Figure 1 , Figure 3 , Figure 4As shown, the first solenoid valve 22 and the second solenoid valve 23 are both open, and the first chamber 43 and the second chamber 44 are both connected to the high-pressure gas source as air inlet chambers, and the high-pressure gas is introduced to make the gas pressures in the two chambers the same; initially, the first piston 421 itself can push the second piston 422 to move to the right (in the process of moving from the left position to the middle position), but in the middle position, the first piston 421 will be blocked by the push structure of the third piston 422, and cannot continue to push the second piston 422 to move to the right (the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface). On the other hand, although the third piston 423 and the second piston 422 can provide a driving force greater than the first piston 421 (the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface), the second piston 422 itself cannot push the first piston 421 to move leftward (the area of ​​the first force-bearing surface is larger than the area of ​​the second force-bearing surface), and the third piston 423 is blocked at its left limit position and cannot continue to push the first piston 421, so that the piston rod 45 can stay in the middle position between the left position and the right position, and at the same time cooperate with the positioning device 46 to stop the piston rod 45 and the shift actuator in the neutral gear position after the chamber is depressurized.

[0070] 3) The process of shifting from neutral to 2nd gear is the opposite of the process of shifting from neutral to 1st gear. Figure 1 , Figure 4 , Figure 5 As shown, the first chamber 43 is an air intake chamber, and there is no air pressure in the second chamber 44, so the third piston 423 and the second piston 422 cannot prevent the first piston 421 from driving the piston rod 45 to move rightward to the right position.

[0071] 4) The process of shifting from 2nd gear to neutral is similar in principle to that of shifting from 1st gear to neutral, and only the principle is introduced: the first chamber 43 and the second chamber 44 are both intake chambers. Since the third piston 423 and the second piston 422 can provide a pushing force greater than that of the first piston 421 (the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface), but the second piston 422 itself cannot push the first piston 421 to the left (the area of ​​the first force-bearing surface is larger than the area of ​​the second force-bearing surface), and the third piston 423 is blocked at its left limit position and cannot continue to push the first piston 421, the piston rod 45 can stay in the middle position between the left position and the right position.

[0072] According to the description of the working process of the piston cylinder driven gear shifting of the present invention, when the gearbox of the present invention returns to neutral, that is, when the cylinder piston rod 45 returns to the middle position, the first solenoid valve 22 and the second solenoid valve 23 are opened at the same time, and the first chamber 43 and the second chamber 44 are simultaneously intake air to push the piston rod 45 to move toward the middle. The displacement sensor 33 detects the displacement value of the piston rod 45 in real time. When it is judged that the neutral position is reached according to the displacement value (neutral corresponds to a piston rod displacement value, and the neutral position can be known according to the displacement value), the first solenoid valve 22 and the second solenoid valve 23 are closed (after the normally closed first solenoid valve 22 and the second solenoid valve 23 are powered off and closed, the upstream air path is blocked, the two chambers are connected to the atmosphere, and the cylinder is depressurized). Due to the difference in shape between the first chamber 43 and the second chamber 44, the volume of the second chamber 44 is larger than that of the first chamber 43. If the first solenoid valve 22 and the second solenoid valve 23 are closed at the same time, the pressure drop rate of the second chamber 44 is slower than that of the first chamber 43. The pressure difference will push the second piston 422 to drive the piston rod 45 (cylinder shaft) to move to the left, resulting in a position change, causing the gear to be out of the neutral position, reflecting the problem of difficulty in shifting gears or gear jumping when shifting gears.

[0073] In response to the above problems, the shift piston cylinder of the present invention also includes the following shift control method, which sets the second solenoid valve 23 to be powered off and closed first (the second chamber 44 with a larger volume starts to relieve pressure first), and after a delay time t, the first solenoid valve 22 is closed (the first chamber 43 with a smaller volume delays pressure relief), so that the air pressure difference between the two chambers during the pressure relief process does not exceed a certain value (when the air pressures of the two chambers act on the first force-bearing surface and the second force-bearing surface respectively, the resulting force is less than the limiting force generated by the positioning device 46), thereby ensuring that the first solenoid valve 22 and the second solenoid valve 23 are closed, and the piston rod stays in the neutral position during the pressure relief process of the chamber air cylinder. The initial delay time t can be determined by the gearbox or cylinder offline calibration.

[0074] In the shifting piston cylinder's shifting control method of the present invention, the delay time t when returning to neutral gear will be self-corrected during each shifting control process according to the displacement fluctuation of the piston rod 45 during the air withdrawal and pressure relief process. The value of the delay time t can directly reflect the exhaust status of the solenoid valves 1 and 2. If it reaches the early warning range, the instrument will remind you to inspect the solenoid valve for exhaust. If the delay time reaches the fault range, the instrument will report a fault and require you to check whether the corresponding solenoid valve has a fault, such as the exhaust port is blocked or the valve core is stuck and cannot return to its position.

[0075] Specifically, Figure 7As shown in the figure, t in the figure is the closing delay time of the first solenoid valve 22 set in the TCU after the gear shifting of the transmission is calibrated offline; t1 is the upper limit value of the time t in the gear shifting logic, and t2 is the lower limit value of the time t in the gear shifting logic. If t2 < t < t1, the transmission can complete the gear shifting without jumping gears after shifting to neutral. Otherwise, it will be determined that there is a solenoid valve exhaust fault, and the solenoid valve exhaust needs to be repaired. It can only be restored to use after the fault is eliminated. t10 is the upper limit value of the time t for reminding maintenance, and t20 is the lower limit value of the time t for reminding maintenance. If t20 < t < t10, it is considered to be in a normal state; if t2 < t < t20 or t10 < t < t1, it will be considered that there is an abnormality in the solenoid valve exhaust, and attention needs to be paid to inspection, but it has not reached the fault reporting level. It will remind to check the solenoid valve exhaust, and the transmission can still complete the gear shifting.

[0076] Therefore, the gear shifting control method of the shifting piston cylinder of the present invention can avoid gear jumping caused by the offset of the piston rod after gear shifting; at the same time, it can calibrate the closing delay time t of the first solenoid valve 22 online; it can also diagnose faults online according to the closing delay time t. The specific steps are as follows:

[0077] 1) After receiving the neutral gear command, the first solenoid valve 22 and the second solenoid valve 23 are energized and opened, and the first chamber 43 and the second chamber 44 are connected to the air source.

[0078] 2) The TCU judges whether there is a circuit fault (short circuit / open circuit) according to the voltage and current in the circuits where the first solenoid valve 22 and the second solenoid valve 23 are located; if so, the first solenoid valve 22 and the second solenoid valve 23 are closed, and at the same time, a circuit fault of the first solenoid valve 22 or the second solenoid valve 23 is reported, prompting to check the corresponding solenoid valve circuit. If there is no circuit fault, it is judged whether the neutral gear is reached through the piston rod displacement.

[0079] 3) In the neutral gear displacement judgment, if the neutral gear displacement is not reached, the first solenoid valve 22 and the second solenoid valve 23 are closed again and steps 1), 2), and 3) are tried again. After the set number of attempts, a neutral gear failure fault is reported, and at the same time, it is prompted to stop the vehicle for detecting the air leakage fault of the shifting cylinder. The air leakage fault detection of the shifting cylinder will be introduced below; if the neutral gear displacement is reached, the next step of cylinder pressure relief is entered.

[0080] 4) In the cylinder pressure relief, first, the second solenoid valve 23 is powered off and closed, and after the delay time t, the first solenoid valve 22 is powered off and closed. At this time, the cylinder pressure relief is completed, and there is no air pressure in both the first chamber 43 and the second chamber 44. At this time, it is judged whether the piston rod displacement is in the neutral gear state through the displacement sensor 33. If so, the neutral gear is successfully returned. If not, it enters the steps of online fault diagnosis and self-correction of the delay time t.

[0081] 5) During the online fault diagnosis and the self-correction process of the delay time t, first of all, the failure to reach the neutral displacement indicates that during the air evacuation process of the chamber, with the first solenoid valve 22 closed at the delay time t, the different rates of air pressure drop in the first chamber 43 and the second chamber 44 result in an excessive air pressure difference, generating a thrust that destroys the balance of the piston group, overcoming the resistance of the positioning device 46, causing the first piston 421 or the second piston 422 to be pushed, and ultimately resulting in the displacement of the piston rod and the failure of the gear position to return to neutral. When this situation occurs, the direction of the piston rod offset is judged according to the displacement value, and then the delay time t is corrected and it is diagnosed whether there is an abnormality or a fault.

[0082] The correction process specifically includes: ① If S0 - S > 0, where S0 is the neutral displacement and S is the current displacement, that is, the piston rod is biased towards the second chamber 44, it indicates that the air pressure in the first chamber 43 during the pressure relief process exceeds the air pressure in the second chamber 44 too much during the air evacuation process (the delay time for the first solenoid valve 22 to close is too long, that is, there may be a problem with the first solenoid valve 22 in terms of poor exhaust, resulting in normal exhaust and pressure relief in the second chamber 44 while the pressure relief in the first chamber 43 becomes slower). Therefore, it is necessary to cut off the power supply in advance to close the first solenoid valve 22 (after closing the solenoid valve, the chamber is connected to the atmosphere for air evacuation), then correct t = t - 1 (the correction amount each time when correcting t can be set according to the actual situation). After correction, it is judged whether t reaches the range of reporting a fault (t < t2). If it reaches, it indicates that there is an exhaust fault in the first solenoid valve 22, and a fault message is reported to prompt maintenance; if it does not reach the range of reporting a fault, it is judged whether it reaches the warning range (t < t20). If so, it indicates that the exhaust of the first solenoid valve 22 is abnormal, and a reminder for maintenance inspection is given, and the first solenoid valve 22 and the second solenoid valve 23 are energized and opened according to the new delay time t for gear shifting again; if not, the first solenoid valve 22 and the second solenoid valve 23 are directly energized and opened according to the new delay time t for gear shifting again. The above process is the correction of the delay time t and the fault detection of the first solenoid valve 22.

[0083] ② The fault detection of the second solenoid valve 23 is basically the same as the above principle. Specifically, if S0-S<0, where S0 is the neutral displacement and S is the current displacement, that is, the piston rod deviates to the first chamber 43, it means that the pressure drop rate of the second chamber 44 is low and the air is released slowly. It may be that the exhaust port of the second solenoid valve 23 is blocked, and it is necessary to increase the delay time t to allow the second chamber 44 to release air for a while. Then, t=t+1 is corrected (the correction amount each time when correcting t can be set according to the actual situation). After correction, it is determined whether t reaches the range of fault reporting (t>t1). If it reaches, it indicates that the exhaust of the second solenoid valve 23 is faulty, and the fault is reported to prompt maintenance; if it does not reach the range of fault reporting, it is determined whether it reaches the range of early warning (t>t10). If so, it indicates that the exhaust of the second solenoid valve 23 is abnormal, and a maintenance inspection is prompted, and the first solenoid valve 22 and the second solenoid valve 23 are powered on according to the new delay time t to open the gear again; if not, the first solenoid valve 22 and the second solenoid valve 23 are powered on according to the new delay time t to open the gear again.

[0084] At this point, the gearbox shifting process with fault detection and self-correction of the gear shifting piston cylinder system of the present invention is completed.

[0085] This solution sets a delay time so that the two chambers open their valves to release air in turn, preventing pressure from being generated and causing piston displacement. At the same time, the control algorithm is used to achieve automatic online correction of the delay time, improve the adaptability of the gas circuit system, and realize fault diagnosis such as solenoid valve core sticking, valve core leakage, exhaust port blockage and cylinder leakage. The state of the solenoid valve pressure relief port is then fed back based on the delay time to predict faults in advance, prompt maintenance, and reduce the impact of faults on vehicle operations.

[0086] The piston cylinder controller 51 of the shift piston cylinder system of the present invention can execute instructions stored in the memory to implement the shift piston cylinder fault detection method of the present invention, which is specifically introduced in the following shift piston cylinder fault detection method embodiment.

[0087] Shift piston cylinder fault detection method embodiment:

[0088] The shift piston cylinder fault diagnosis method of the present invention, that is, the shift cylinder gas leakage fault detection method mentioned in step 3) of the above-mentioned shift system shift control method, is introduced in detail below.

[0089] The displacement of the piston rod 45 allowed by the gear shift mechanism from neutral to the dead point of each gear is Figure 1The displacement between the corresponding positioning grooves 451 (determining the gear positioning) on ​​the middle piston rod 45 is ΔS. The gear dead point is the maximum displacement point that the stop structure of the corresponding gear of the shift mechanism allows the moving parts to reach; the stop structure is: a stop structure in the shift mechanism that blocks or limits the extreme displacement of the moving parts in order to prevent the moving parts (such as the shift fork, the coupling tooth) from excessive movement and causing damage to the related parts. For example, in the shift mechanism, the allowable moving distance of the piston rod 45 from neutral to 1st gear is determined by the stop structure of 1st gear in the shift mechanism, and in the actual gear shifting process, due to the existence of the cylinder positioning device 46, the shift positioning steel ball 461 will force the piston rod 45 to stay at the position corresponding to the positioning groove 451 of the gear and the shift positioning steel ball 461 (this position is the gear positioning of the corresponding gear). Obviously, there will be a certain clearance or margin between the piston rod 45 at this position (gear positioning) and the position when the corresponding gear stop structure blocks it (gear dead point), so as to ensure that the shift positioning steel ball 461 in the positioning device 46 is smoothly and stably inserted into the corresponding positioning groove 451, and the size of this clearance or margin is ΔS. In other words, if Figure 8 As shown, when the shift mechanism shifts from neutral to first gear, the maximum movement distance allowed by the movable parts of the shift mechanism for the piston rod 45 is a, and the distance between the middle neutral positioning groove 451-2 corresponding to neutral and the right first gear positioning groove 451-3 corresponding to first gear (the distance between the gear position positioning of neutral to the gear position positioning of first gear) is b, then ab=ΔS.

[0090] Specifically, Figure 8 The figure shows the state where the gear shift positioning steel ball 461 is stuck in the second gear positioning groove 451-1 corresponding to the second gear on the piston rod after the gas is released in the second gear. Fig. 9 The figure shows the state of the positioning device 46 when the first solenoid valve 22 for shifting into the 2nd gear is opened, the first chamber 43 is ventilated to establish air pressure, which overcomes the resistance generated by a certain positioning device 46, and pushes the piston together with the piston rod to generate a rightward movement trend. Under this trend, the piston rod drives the relevant moving parts in the shift mechanism, and after continuing to move ΔS, it is stopped by the stop structure of the 2nd gear position. It can be seen that at this time, since the piston rod 45 moves more to the right (in the 2nd gear direction) by the displacement of ΔS in the clearance, the shift positioning steel ball 461 is relatively Figure 8The state after the air is released and the pressure is released in the middle 2nd gear. Since the shift positioning steel ball 461 can only move in the vertical direction, the second gear positioning groove 451-1 will be offset to the right relative to the shift positioning steel ball 461 after the piston rod 45 moves to the right, causing the shift positioning steel ball 461 to press on the 45° inclined surface of the left side wall of the second gear positioning groove 451-1 under the vertical downward force F of the spring 462, and generate a horizontal rightward force component of F·tan45° on the piston rod 45, which can achieve the locking of the gear position. In addition, the driving force on the piston generated by the shift cylinder when the air pressure is established will obviously be greater than this component force (otherwise the positioning steel ball cannot be separated from the positioning groove and the gear cannot be shifted). At the same time, this component force will cause the piston rod to move in the opposite direction by a distance of ΔS after the cylinder pressure is released, so that the shift positioning steel ball 461 completely enters the positioning groove 451 of the corresponding gear position (restored to Figure 8 status), lock the gear to complete the shifting process.

[0091] Figure 8 The state shown is the state of cylinder pressure relief after the 2nd gear is engaged. At this time, the indication of the displacement sensor 33 is S2, i.e., the displacement value of the 2nd gear; Fig. 9 The state shown is that the cylinder is not depressurized after the second gear is engaged, that is, the first solenoid valve 22 is not powered off and closed, and the first chamber 43 still maintains the state of the shift pressure. At this time, the indication of the displacement sensor 33 is S3, that is, the displacement of the piston rod when the piston rod pushes the actuating part of the shift mechanism to be blocked by the gear stop structure; at this time, the first solenoid valve 22 is powered off and closed, the first chamber 43 is disconnected from the air source 10 and connected to the atmosphere, the piston rod 45 loses the push of the shift force, and under the component force of F·tan45°, the piston rod 45 moves from Fig. 9 Status restored to Figure 8 state, the indication of the displacement sensor 33 will change from S3 to S2, with a change of ΔS. Using this principle, after the first solenoid valve 22 is powered on and opened (the first chamber 43 establishes the shifting air pressure), the normally open third solenoid valve 21 is powered on and closed (the air circuit is disconnected), and the first chamber 43 and the air circuit 24 are maintained airtight. If there is no air leakage fault, the air pressure in the first chamber 43 will remain unchanged, the piston rod 45 will always be affected by the shifting force, and the displacement sensor value will also remain at S3; if there is an air leakage fault, the air pressure in the first chamber 43 will gradually decrease to atmospheric pressure, the shifting force on the piston rod 45 will gradually decrease to below F·tan45°, and the displacement sensor value will change from S3 to S2.

[0092] According to the above characteristics and principles, the present invention also proposes a shift cylinder fault detection method in the parking state (piston cylinder sealing performance detection method, the air tightness of the piston cylinder is detected to find out whether there is a leakage fault). This method is suitable for detecting and troubleshooting faults such as difficulty in shifting gears (the cylinder piston is difficult to return to the middle position), such as Fig.10 As shown, the specific steps include:

[0093] 1) After manually triggering the shift cylinder leakage fault detection, the first solenoid valve 22 and the second solenoid valve 23 are opened, and then the voltage and current in the circuit where the first solenoid valve 22 and the second solenoid valve 23 are located are used to determine whether there is a circuit fault in solenoid valve 1 or 2. If there is a circuit fault, it is reported and the circuit of the corresponding solenoid valve needs to be repaired. If there is no circuit fault, proceed to step 2).

[0094] 2) After the first solenoid valve 22 and the second solenoid valve 23 are opened, the cylinder piston rod 45 should be driven to move toward the neutral position. In step 2), it is determined whether the piston rod 45 reaches the neutral displacement according to the displacement sensor 33. If the neutral displacement is reached, it is considered that the overall air tightness of the cylinder is good and there is no fault.

[0095] If the neutral displacement is not reached, the displacement direction of the piston rod is determined based on the actual displacement. ① If S0-S>0, where S0 is the neutral displacement and S is the actual displacement, it means that the piston rod 45 is displaced toward one side of the second solenoid valve 23 (second chamber 44), indicating that the air pressure in the second chamber 44 is insufficient, and there may be a leakage problem, which requires further detection; ② If S0-S<0, it means that the piston rod 45 is displaced toward one side of the first solenoid valve 22 (first chamber 43), indicating that the air pressure in the first chamber 43 is insufficient, and there may be a leakage problem, which requires further detection. The detection principles of the two chambers are the same, and the detection methods correspond to each other. The following is a detailed description of ② further detection of the first chamber 43 as an example.

[0096] 3)② Leakage detection of the first chamber 43. Currently, under the operation of steps 1) and 2), the first solenoid valve 22 and the second solenoid valve 23 are both in the open state, and the piston rod 45 is biased to the side of the first chamber 43. At this time, first turn off the power to close the second solenoid valve 23, and the second chamber 44 is connected to the atmosphere to release pressure. At this time, only the first solenoid valve 22 is powered on and opened, and there is shift air pressure in the first chamber 43. Determine whether the displacement of the piston rod 45 changes. If not, it means that although the first solenoid valve 22 is powered on, the valve core is not opened normally. The first solenoid valve 22 is reported to be stuck and the valve core needs to be repaired. The detection ends here.

[0097] If the displacement changes and the 2nd gear is engaged, the shifting air pressure maintains the shifting force of the piston rod 45. Therefore, at this time, the piston rod 45 reaches the maximum displacement of the 2nd gear and is stopped by the stop structure. The piston rod displacement value S3 at this time is recorded. Then the normally open third solenoid valve 21 is energized and closed to cut off the air path. The first chamber 43 and the air path 24 become a closed airtight space. After maintaining the set time, the piston rod displacement value S2 at this time is recorded. If |S3-S2|≥ΔS, it indicates that the above-mentioned airtight space is not airtight and there is leakage, resulting in a decrease in air pressure and failure to maintain the shifting force. The piston rod 45 is displaced under the action of F·tan45°. It is necessary to check the airtightness of the first solenoid valve 22, the first piston 421 and the cylinder body 41, and the airtightness of the air path 24 when the second solenoid valve 23 is closed.

[0098] Otherwise, it is considered that the first chamber 43 is well sealed. It may be that the actuator or the cylinder is stuck inside and cannot return to the neutral position. Relevant inspection is required.

[0099] The detection of the second chamber 44 is the same as that of the first chamber 43, and will not be repeated here.

[0100] During the above shift cylinder leakage fault detection process, it is necessary to try to shift gears. Therefore, for driving safety, it is necessary to stop the vehicle, manually trigger the instrument combination button, enter the fault detection program, and the final test results will be displayed on the instrument panel.

[0101] At this point, the shift cylinder sealing performance detection method process is completed.

[0102] Shift piston cylinder embodiment 2:

[0103] Another embodiment of the shifting piston cylinder of the present invention, the piston cylinder used for driving the shifting in this embodiment is different from that in the above embodiments, and the difference is only in that, Figure 6 As shown, the piston 42 is a single body structure, the left end face of the piston 42 is a first force-bearing face, the right end face is a second force-bearing face, and the cross-section of the right part of the piston 42 is smaller than that of the left part, that is, the piston 42 in this embodiment is equivalent to the first piston 421 and the second piston 422 in the above embodiments, and the right part of the piston 42 is inserted into the third piston.

[0104] The piston cylinder in this embodiment can also drive the AMT shift mechanism to adopt the shift control method of the above embodiment to achieve shifting, while performing online calibration of the delay time t and online fault diagnosis; it can also perform shift cylinder leakage fault detection in the above embodiment.

[0105] Therefore, it should be pointed out that the “first piston and the second piston” in the present invention can be either two pistons on a piston rod or two parts of a piston on a piston rod.

Claims

1. A shift piston cylinder system, comprising a shift mechanism, a piston cylinder driving the shift mechanism, a piston cylinder driving unit, and a controller connected to the piston cylinder driving unit; It is characterized in that The piston cylinder comprises: a piston rod connected to the shift mechanism, a cylinder body, a piston system, a positioning device and a position sensor for detecting the position of the piston system or the piston rod; the cylinder body is divided into at least two chambers by the piston system; the positioning device will apply force to force the piston system or the piston rod to stay at the position corresponding to the current gear position after entering the corresponding gear position; When the piston system is driven to move, the shift mechanism can reach the gear dead point of the corresponding gear by pushing the piston rod. After the driving force is removed, the piston system or the piston rod can return to the gear position of the corresponding gear under the action of the positioning device; the gear dead point is the maximum point reached by the moving parts in the shift mechanism at the corresponding gear. The piston cylinder drive unit includes: a pressure source and a valve; the pressure source can be connected to the chamber to input a fluid of a certain pressure into the corresponding chamber; the valve is controlled by the controller to control the connection and disconnection of the fluid channel from the pressure source to the corresponding chamber, and the pressure relief of the corresponding chamber; The controller executes the instructions to implement the following sealing performance detection method for the corresponding chamber: 1) Introduce a pressurized fluid into a chamber; 2) When the position sensor detects that the piston system or the piston rod reaches the displacement of the gear dead point of the corresponding gear, the fluid channel of the corresponding chamber is closed; 3) If the position sensor detects a change in the position of the piston system or the piston rod within the set time after shutdown, it means that there is a leakage fault in the corresponding chamber; if the position sensor does not detect a change in the position of the piston system or the piston rod, it means that the sealing of the corresponding chamber is good.

2. The shift piston cylinder system according to claim 1, It is characterized in that In step 3), the position of the piston system or the piston rod changes as follows: the piston system or the piston rod changes from a displacement corresponding to the gear dead point of the corresponding gear to a displacement corresponding to the gear positioning.

3. The shift piston cylinder system according to claim 1, It is characterized in that The gear dead point of the corresponding gear is determined by the stop structure of the gear shift mechanism at the corresponding gear, and the gear positioning of the corresponding gear is determined by the positioning device of the piston cylinder.

4. The shift piston cylinder system according to claim 1, It is characterized in that The piston rod moves left and right along a set axis and has three set positions: left, middle, and right, which correspond to the first gear, neutral, and second gear of the shift mechanism respectively; Corresponding to the 1st gear and the 2nd gear, the shift mechanism includes a stop structure that determines the dead point of the gear position of the gear; corresponding to the 1st gear, the 2nd gear and the neutral gear, the positioning device includes a positioning structure that determines the positioning of the gear position of the gear; The piston system includes a first piston, a second piston, and a third piston; the first piston and the second piston are fixed to the piston rod; the cylinder body includes a first chamber and a second chamber distributed on the left and right; The first piston comprises a first force-bearing surface for being subjected to rightward pressure by the medium in the first chamber, and the first piston is slidably assembled in the first chamber; The second piston comprises a second force-bearing surface for being exerted with leftward pressure by the medium in the second chamber; The third piston includes a third force-bearing surface, which is used to be exerted with a leftward pressure by the medium in the second chamber; a limiting structure is provided on the third piston, and a blocking structure is provided in the cylinder body, and the limiting structure is used to cooperate with the blocking structure in the cylinder body so that the third piston is blocked from moving to the left; the third piston moves left and right, and has a left limit position and a right limit position; the third piston is a sleeve structure, and the piston rod and the second piston are inserted into the sleeve hole to the right, and the second piston is sealed and slidably matched with the sleeve hole; the third piston includes a left-side plug-in sleeve and a right-side ring platform, and the plug-in sleeve is inserted into the first chamber to the left, and a push structure is provided on the plug-in sleeve, which is used to push the first piston to the left or to be pushed to the right by the first piston to drive the third piston to move to the right limit position; the outer peripheral surface of the ring platform is slidably and sealedly matched with the second chamber; when the limiting structure cooperates with the blocking structure, the third piston is in the left limit position and corresponds to the middle position or left position of the piston rod; when the piston rod is in the right position, the corresponding third piston is in the right limit position; The area of ​​the first force-bearing surface is larger than that of the second force-bearing surface, and the area of ​​the first force-bearing surface is smaller than the sum of the areas of the second force-bearing surface and the third force-bearing surface; the volume of the second chamber is larger than that of the first chamber.

5. The shift piston cylinder system according to claim 4, It is characterized in that The positioning device includes a positioning spring, a positioning steel ball and a positioning groove arranged on the piston rod corresponding to each gear position, and the positioning groove is a trumpet-shaped opening; under the action of the elastic force of the positioning spring, the positioning steel ball drives the piston rod to move axially so that the positioning steel ball stays at the center position of the trumpet-shaped opening of the positioning groove; the distance from the center position of the positioning groove corresponding to the neutral gear to the center position of the positioning groove corresponding to the 1st gear or the 2nd gear on the piston rod is smaller than the displacement distance of the piston rod from the neutral gear position to the gear dead point corresponding to the 1st gear or the 2nd gear.

6. The shift piston cylinder system according to claim 4, It is characterized in that The right side of the ring platform of the third piston has an annular end face, which is used to be pressed to the left by the medium in the second chamber to form the third force-bearing surface; the cross-sectional area of ​​the first chamber is smaller than that of the second chamber, and a first step is formed between the first chamber and the second chamber; the outer diameter of the sleeve is smaller than the outer diameter of the ring platform, and a second step is formed between the sleeve and the ring platform, and the left end face of the second step is used to cooperate with the right end face of the first step; the second step forms a limiting structure for the third piston, and the first step forms a blocking structure in the cylinder body.

7. The shift piston cylinder system according to claim 4, It is characterized in that The valve comprises a first controlled valve, a second controlled valve and a third controlled valve, the first and second controlled valves are both two-position three-way valves, and the third controlled valve is a two-position two-way valve; when the first and second controlled valves are in the first valve position, the first controlled valve is connected to the pressure relief port and the first chamber, and the second controlled valve is connected to the pressure relief port and the second chamber; When the first and second controlled valves are in the second valve position, the first controlled valve connects the third controlled valve outlet and the first chamber, and the second controlled valve connects the third controlled valve outlet and the second chamber; when the third controlled valve is in the first valve position, the pressure source outlet and the third controlled valve outlet are sealed; when the third controlled valve is in the second valve position, the pressure source outlet and the third controlled valve outlet are connected.

8. The shift piston cylinder system according to claim 4, It is characterized in that Before step 1), the following preliminary tests are also performed: a) introducing pressurized fluid into the first chamber and the second chamber simultaneously; b) If the position sensor detects that the position of the piston system or the piston rod is biased towards the 1st gear, the sealing performance test of the first chamber is performed; if the position sensor detects that the position of the piston system or the piston rod is biased towards the 2nd gear, the sealing performance test of the second chamber is performed.

9. The shift piston cylinder system according to claim 7, It is characterized in that In step 2), if the position sensor does not detect the displacement of the piston system or the piston rod reaching the gear dead point of the corresponding gear, a fault of the two-position three-way valve of the corresponding chamber is reported.

10. A method for detecting a shift piston cylinder fault, It is characterized in that A sealing performance detection method in a shift piston cylinder system as claimed in any one of claims 1 to 9 is adopted.

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