A power shift gearbox for overhead contact line operation vehicles

Abstract

This utility model relates to the field of transmission technology for rail engineering vehicles, specifically to a power shift gearbox for overhead contact line operation vehicles. It includes an integrated housing, a hydraulic torque converter, a four-speed mechanical transmission mechanism, a clutch module, a hydraulic control system, and a TCU intelligent control system. The hydraulic torque converter and the four-speed mechanical transmission mechanism are integrated into the integrated housing. This utility model combines pure hydraulic transmission with a four-speed gearbox design, achieving a total speed ratio range of 7.38 times. Combined with the continuously variable transmission characteristics of the hydraulic torque converter, it achieves full coverage from extremely low speeds of 0 km / h to high speeds of over 80 km / h, meeting the dual needs of operation and relocation. Optimized pressure-reducing valves in the hydraulic system and throttle port design of the clutch piston reduce shift shock from the perspectives of pressure regulation and engagement time control, solving the problem of large shock when shifting into first gear. The TCU and engine ECU work together to control the system, primarily through active torque adjustment and secondarily through gear intervention, achieving high-precision stable driving at speeds of 1-5 km / h and preventing overheating and wear of the braking system.

Description

Technical Field

[0001] This utility model relates to the field of transmission technology for rail engineering vehicles, specifically to a power shift gearbox for overhead contact line operation vehicles. Background Technology

[0002] The overhead contact line maintenance vehicle is a special type of rail vehicle specifically designed for the construction, inspection, and maintenance of railway overhead contact lines. Its transmission system must meet special requirements such as high flexibility, precise control, frequent start-stop, and adaptability to complex working conditions, making it significantly different from traditional rail vehicles.

[0003] The core requirements for the transmission system of the overhead contact line maintenance vehicle include: First, high-precision speed control, which requires stepless speed regulation from 0 to 80 km / h. Among them, the overhead contact line maintenance requires stable driving at extremely low speeds of 0.5 to 5 km / h, the laying operation requires uniform traction at 5 to 20 km / h, and the relocation operation needs to support a high-speed mode of 80 km / h; Second, low-speed high-torque output to meet the needs of starting on slopes or tension control.

[0004] Currently, the gearboxes of overhead contact line vehicles have evolved from mechanical transmission to hydraulic transmission. However, the existing hydraulic-mechanical transmission power shift gearboxes have two major problems: First, in order to achieve low-speed, high-torque output, a higher gear ratio needs to be set, resulting in severe shift shock due to the large traction force when shifting from neutral to first gear. Second, they cannot achieve low constant speed function. Since the working vehicle has no traction weight, the traction force is always greater than the driving resistance on straight tracks, requiring additional hydraulic braking to achieve low constant speed driving, which increases the system complexity and operating cost. Utility Model Content

[0005] In view of the shortcomings of existing hydraulic mechanical power shift gearboxes, such as large shift shock and inability to achieve low constant speed without braking, this utility model provides a power shift gearbox for overhead contact line operation vehicles, which can achieve wide speed range adjustment, reduce shift shock and achieve high-precision low constant speed control.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A power shift transmission for overhead contact line operation vehicles includes an integrated housing, a hydraulic torque converter, a four-speed mechanical transmission mechanism, a clutch module, a hydraulic control system, and a TCU intelligent control system. The hydraulic torque converter and the four-speed mechanical transmission mechanism are integrated into the integrated housing. The clutch module is located outside the integrated housing. The hydraulic control system is connected to the clutch module. The TCU intelligent control system is connected to both the hydraulic control system and an external engine ECU. The TCU intelligent control system establishes real-time communication with the engine ECU via a CAN bus. Its built-in dynamic adaptive torque resistance algorithm is an adaptive PID controller, which can automatically adjust the proportional, integral, and derivative parameters according to changes in vehicle running resistance.

[0008] The first gear ratio of the four-speed mechanical transmission mechanism is 5.29, and the fourth gear ratio is 0.72; the main solenoid valve module of the hydraulic control system is equipped with a pressure reducing valve, the pressure reducing valve includes a pressure reducing valve control spring, the clutch module includes a clutch piston, and the clutch piston is equipped with a clutch piston throttle port.

[0009] Furthermore, the four-speed mechanical transmission mechanism is connected to an output shaft, which is arranged parallel to the axle drive shaft.

[0010] Furthermore, the clutch module is detachably connected to the integrated housing, and the clutch module also includes a clutch outer hub, with the clutch piston cooperating with the clutch outer hub.

[0011] Furthermore, the control spring of the pressure reducing valve has a specification of φ3mm×25mm.

[0012] Furthermore, the diameter of the clutch piston throttle orifice is φ1.5mm.

[0013] Furthermore, the shaft drop distance of the four-speed mechanical transmission mechanism is 677mm.

[0014] The technical solution provided by this utility model has the following advantages compared with the known prior art:

[0015] Wide speed ratio range adapts to complex working conditions: Through the combination of pure hydraulic transmission and four-speed gearbox, the total speed ratio range reaches 7.38 times. Combined with the continuously variable transmission characteristics of the hydraulic torque converter, it can achieve full coverage from extremely low speed of 0km / h to high speed of over 80km / h, meeting the dual needs of operation and relocation.

[0016] Significantly improved shift smoothness: Optimization of the hydraulic system's pressure reducing valve and design of the clutch piston throttle port reduce shift shock from the dimensions of pressure regulation and engagement time control, solving the problem of large shock when shifting into first gear.

[0017] Achieving brakeless low constant speed control: The TCU and engine ECU work together to control the system, with active torque adjustment as the main method and gear intervention as a secondary method, to achieve high-precision stable driving at 1-5km / h and avoid overheating and wear of the braking system.

[0018] High reliability and easy maintenance: The integrated structure and parallel output design improve transmission reliability, and the external clutch facilitates quick maintenance and reduces usage and maintenance costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the clutch module structure of this utility model.

[0022] The labels in the diagram represent:

[0023] 1. Integrated housing; 2. Hydraulic torque converter; 3. Four-speed mechanical transmission mechanism; 4. Clutch module; 5. Hydraulic control system; 6. TCU intelligent control system; 7. Output shaft; 41. Clutch piston; 411. Clutch piston throttle port; 42. Clutch outer hub; 51. Main solenoid valve module; 52. Pressure reducing valve; 521. Pressure reducing valve control spring. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0025] The present invention will be further described below with reference to the embodiments.

[0026] Example

[0027] Reference Figure 1-2This is the first embodiment of the present invention, a power shift gearbox for a catenary work vehicle, comprising an integrated housing 1, a hydraulic torque converter 2, a four-speed mechanical transmission mechanism 3, a clutch module 4, a hydraulic control system 5, and a TCU intelligent control system 6. The hydraulic torque converter 2 and the four-speed mechanical transmission mechanism 3 are integrated within the integrated housing 1. The clutch module 4 is bolted to the outside of the integrated housing 1. The hydraulic control system 5 has oil pipes connecting the clutch module 4 to the main electronic control valve module 51. The TCU intelligent control system 6 is connected to the hydraulic control system 5, the external engine ECU, and a speed sensor via wiring harnesses.

[0028] The gear set of the four-speed mechanical transmission mechanism 3 is precisely designed, with a first gear ratio of 5.29 and a fourth gear ratio of 0.72. Power transmission is achieved through gear meshing. Its output shaft 7 is parallel to the axle drive shaft, with a shaft drop distance of 677mm. In the main electro-hydraulic valve module 51 of the hydraulic control system 5, the pressure reducing valve control spring 521 of the pressure reducing valve 52 adopts a φ3mm×25mm specification (adapted and adjusted size) to reduce the main system pressure from the existing 20MPa to 12MPa; a φ1.5mm clutch piston throttle port 411 is opened on the clutch piston 41, which extends the shift engagement time from 0.3s to 0.8s.

[0029] When performing overhead contact line maintenance, the driver activates the "low constant speed" mode and sets a target speed of 3 km / h. After receiving the command, the TCU intelligent control system 6 calculates the theoretical output speed N_set, sends an initial torque request (40% of the rated torque) to the engine ECU, and controls the clutch module 4 to engage for starting. During driving, the TCU intelligent control system 6 obtains the actual speed N_actual of the output shaft 7 in real time through the speed sensor, calculates the deviation ΔN=N_actual-N_set. If ΔN>0, the dynamic adaptive PID algorithm calculates a lower torque request value (such as 35%) and sends it to the ECU to reduce the engine output torque. If ΔN remains positive and the torque has been reduced to the minimum, the TCU intelligent control system 6 controls the four-speed mechanical transmission mechanism 3 to switch to first gear while maintaining an extremely low torque request. The core principle of the low gear intervention logic is nonlinear control: the TCU maintains an extremely low engine torque while requesting a downshift. The traction force transmitted to the wheels = low engine torque × large transmission ratio. Ultimately, the traction force is still lower than that in a higher gear, achieving rapid deceleration. The traction force drops sharply through the synergy of low gear and low torque, ensuring stable vehicle speed.

[0030] When traveling between locations, the driver switches to high-speed mode, and the four-speed mechanical transmission 3 can shift to fourth gear. Combined with the continuously variable transmission (CVT) characteristics of the torque converter 2, this allows the vehicle to quickly reach a high speed of 80 km / h. During gear shifting, the hydraulic control system 5 reduces system pressure through the pressure reducing valve 52, and the extended engagement time of the clutch piston throttle orifice 411 significantly reduces shift shock and improves driving comfort.

[0031] Working process of power shift transmission

[0032] I. Overview of the Overall Work Process

[0033] The operation of the power shift transmission for overhead contact line work vehicles is achieved through the coordinated operation of a hydraulic torque converter 2, a four-speed mechanical transmission mechanism 3, a clutch module 4, a hydraulic control system 5, and a TCU intelligent control system 6. Power is transmitted from the engine to the four-speed mechanical transmission mechanism 3 via the hydraulic torque converter 2. The engagement and disengagement of the clutch module 4 enables gear shifting, and finally, the output shaft 7 transmits the power to the axle. Throughout the process, the hydraulic control system 5 executes the gear shifting actions, while the TCU intelligent control system 6 achieves precise control of the entire transmission system through communication with the engine ECU.

[0034] II. Working process of each core component

[0035] 1. Working process of hydraulic torque converter

[0036] As the first stage of power input, the hydraulic torque converter 2 operates as follows:

[0037] The engine power is transmitted to the pump wheel of the hydraulic torque converter 2, which drives the pump wheel to rotate;

[0038] The pump impeller drives the turbine to rotate through the kinetic energy transmission of hydraulic oil;

[0039] The guide wheel regulates the flow of hydraulic oil between the pump wheel and the turbine to achieve torque amplification.

[0040] When the vehicle reaches a certain speed, the hydraulic torque converter 2 enters the lock-up state, and the pump wheel and turbine are directly mechanically connected to improve transmission efficiency.

[0041] The pump wheel of the hydraulic torque converter 2 is connected to the output end of the engine, and the turbine is connected to the input end of the four-speed mechanical transmission mechanism 3. The guide wheel is fixed by a one-way clutch. When the speed ratio between the pump wheel and the turbine reaches 0.85-0.9, the lock-up clutch engages to realize mechanical transmission.

[0042] 2. Working process of the four-speed mechanical transmission mechanism

[0043] The four-speed mechanical transmission mechanism 3 achieves gear switching through different combinations of gear sets:

[0044] First gear: A speed ratio of 5.29 is achieved through a specific gear combination, at which point the power transmission path is the longest and the output torque is the greatest;

[0045] 2nd to 4th gear: progressive reduction is achieved through the meshing of different gear pairs, with the 4th gear having a speed ratio of 0.72;

[0046] The switching between gears is accomplished by engaging and disengaging the corresponding clutches in clutch module 4;

[0047] Power is transmitted to output shaft 7 via gear transmission. Output shaft 7 is connected in parallel with the axle drive shaft, achieving a shaft drop of 677mm.

[0048] 3. Collaborative working process of clutch module 4 and hydraulic control system 5

[0049] The coordination between clutch module 4 and hydraulic control system 5 is key to achieving gear shifting.

[0050] The main solenoid valve module 51 of the hydraulic control system 5 receives instructions from the TCU intelligent control system 6;

[0051] The main solenoid valve module 51 controls the flow of hydraulic oil to the corresponding clutch piston 41;

[0052] The pressure reducing valve 52 regulates the system pressure to the set value through its pressure reducing valve control spring 521, which has a specification of φ3mm×25mm.

[0053] Hydraulic oil enters the piston chamber through the clutch piston throttle port 411 with a diameter of φ1.5mm on the clutch piston 41;

[0054] The clutch piston 41 moves under hydraulic pressure and engages with the clutch outer hub 42 to achieve power transmission;

[0055] After the gear shift is completed, the hydraulic control system 5 releases pressure, the clutch piston 41 resets, and the clutch disengages;

[0056] III. Specific working processes under different working conditions

[0057] 1. Low constant speed mode for overhead contact line maintenance operations;

[0058] The driver sets a target speed, such as 3 km / h, and activates the low constant speed mode;

[0059] After receiving the command, the TCU intelligent control system 6 sends an initial torque request to the engine ECU.

[0060] The hydraulic control system 5 controls the engagement of the corresponding clutch, and the vehicle begins to move.

[0061] The actual rotational speed of the output shaft 7 is fed back to the TCU intelligent control system 6 in real time via a sensor.

[0062] The TCU intelligent control system calculates the deviation between the actual speed and the target speed and dynamically adjusts the torque request sent to the engine ECU.

[0063] When the speed deviation remains positive, the TCU intelligent control system 6 controls the four-speed mechanical transmission mechanism 3 to switch to a lower gear.

[0064] By coordinating torque regulation and gear control, the vehicle maintains a set low constant speed.

[0065] 2. High-speed travel mode during site transfer

[0066] The driver switches to high-speed mode, and the TCU intelligent control system 6 receives the high-speed driving command;

[0067] The hydraulic control system 5 controls the clutch module 4 to perform gear shifting operations, and the four-speed mechanical transmission mechanism 3 gradually shifts up.

[0068] When shifted to 4th gear, the speed ratio is 0.72, which, combined with the lock-up state of the hydraulic torque converter 2, achieves efficient transmission.

[0069] During gear shifting, the pressure reducing valve 52 and the clutch piston throttle port 411 on the clutch piston 41 work together to reduce shifting shock.

[0070] The vehicle travels stably at a high speed of 80km / h, achieving maximum power transmission efficiency;

[0071] 3. Detailed instructions for the gear shifting process

[0072] The TCU intelligent control system 6 determines whether a gear shift is needed based on signals such as vehicle speed and throttle position.

[0073] The main solenoid valve module 51 begins to operate after a shift command is sent to the hydraulic control system 5.

[0074] First, disengage the clutch in the current gear: cut off the hydraulic oil supply to the clutch;

[0075] The clutch piston 41 retracts under the action of the return spring, separating from the clutch outer hub 42.

[0076] Then, the clutch engagement of the target gear is controlled: hydraulic oil enters the target gear clutch piston chamber through the pressure reducing valve 52 and the clutch piston throttle port 411;

[0077] The clutch piston 41 moves slowly and comes into contact with the clutch outer hub 42, gradually transmitting torque;

[0078] After the gear shift is completed, the TCU intelligent control system 6 adjusts the engine torque to ensure a smooth power transmission transition.

[0079] IV. The Working Process of the Safety Protection Mechanism

[0080] The TCU intelligent control system 6 continuously monitors the rotational speed of the output shaft 7;

[0081] When the actual speed exceeds the set protection threshold, the engine torque is reduced first to adjust the speed.

[0082] If torque regulation fails to keep the speed within a safe range, the TCU intelligent control system 6 will implement protective measures:

[0083] The relevant clutch is briefly disengaged to cut off power transmission;

[0084] It automatically switches to a lower gear, using the gear ratio to limit the increase in speed;

[0085] In extreme situations, force the vehicle to shift into neutral to ensure safety.

[0086] Through the coordinated operation of the above systems, the power shift gearbox can meet the operating requirements of the overhead contact line maintenance vehicle under different working conditions, and achieve a smooth transition and precise control from low-speed operation to high-speed transfer.

[0087] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of this utility model.

Claims

1. A power shift gearbox for a catenary maintenance vehicle, characterized in that, The system includes an integrated housing (1), a hydraulic torque converter (2), a four-speed mechanical transmission mechanism (3), a clutch module (4), a hydraulic control system (5), and a TCU intelligent control system (6). The hydraulic torque converter (2) and the four-speed mechanical transmission mechanism (3) are integrated in the integrated housing (1). The clutch module (4) is located outside the integrated housing (1). The hydraulic control system (5) is connected to the clutch module (4). The TCU intelligent control system (6) is connected to the hydraulic control system (5) and the external engine ECU. The first gear ratio of the four-speed mechanical transmission mechanism (3) is 5.29, and the fourth gear ratio is 0.

72. The main electronic control valve module (51) of the hydraulic control system (5) is equipped with a pressure reducing valve (52). The pressure reducing valve (52) includes a pressure reducing valve control spring (521). The clutch module (4) includes a clutch piston (41). The clutch piston (41) is equipped with a clutch piston throttle port (411).

2. The power shift gearbox for catenary maintenance vehicle according to claim 1, characterized in that, The four-speed mechanical transmission mechanism (3) is connected to an output shaft (7), which is arranged parallel to the axle drive shaft.

3. The power shift gearbox for catenary maintenance vehicle according to claim 1, characterized in that, The clutch module (4) is detachably connected to the integrated housing (1). The clutch module (4) also includes a clutch outer hub (42), and the clutch piston (41) is configured to cooperate with the clutch outer hub (42).

4. The power shift gearbox for catenary maintenance vehicle according to claim 1, characterized in that, The pressure reducing valve control spring (521) has a specification of φ3mm×25mm.

5. The power shift gearbox for catenary maintenance vehicle according to claim 1, characterized in that, The diameter of the clutch piston throttle orifice (411) is φ1.5mm.

6. The power shift gearbox for overhead contact line operation vehicles according to claim 2, characterized in that, The shaft drop distance of the four-speed mechanical transmission mechanism (3) is 677mm.

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