Control system and control method for heavy-load running of drive axle and crane

Abstract

The invention discloses a drive axle heavy load running control system, a control method and a crane, the system comprises a whole vehicle driving system, a braking system loop for providing braking gas, braking air chambers acting on all axles in the whole vehicle driving system, and a switchable heavy load anti-skid system arranged between the braking system loop and the braking air chambers, the heavy-load anti-skid system generates braking force for each axle or each wheel edge through a braking air chamber on the basis of the running state of each wheel. According to the method, when a vehicle applying a drive axle heavy load running control system, such as a crane, works under different working conditions, braking modes are switched, and the off-road performance of the vehicle, especially a heavy load vehicle, is improved. In addition to switching to the ABS system when the vehicle runs at a high speed, so that the slippage of each wheel is within a control range to prevent the wheels from being locked, when the vehicle runs at a low speed in a heavy load off-road mode, the vehicle can be further switched to the heavy load anti-skid system, and the inter-axle differential mechanism and the inter-wheel differential mechanism are combined to apply braking force to part of the wheels; the power is transmitted to the non-slip wheels, and the problem that the wheels slip and cannot escape is solved.

Description

Technical Field

[0001] The invention relates to a driving technology for an all-terrain crane, and in particular to a driving axle heavy-load driving control system, a control method and a crane. Background Art

[0002] All-terrain cranes, also known as all-road cranes, have a multi-axis mechanical drive chassis. Each axle is equipped with wheel differentials and differential locks, axle differentials and differential locks. Due to the large number of drive axles and the large span of the transmission chain, individual wheels are prone to slip during driving on unpaved roads, causing the entire vehicle to be unpowered and stagnant. The vehicle needs to be freed by attaching differential locks. The axles used in all-terrain cranes have large transmission torque and usually use a tooth-type differential locking mechanism. It has a simple structure, large transmission torque, and does not occupy the layout space of the entire vehicle (the suspension stroke of the all-terrain crane is usually 240 to 300 mm. Due to the height of the entire vehicle and the load-bearing performance requirements of the frame, there are certain requirements for the volume of the axle housing). However, due to this differential locking mechanism, it must be attached and detached when the vehicle is stationary, and steering is not allowed after attachment. The steering operation will cause the axle gear to bear additional torque exceeding the maximum load-bearing capacity of the axle, resulting in axle damage. Therefore, all terrain crane axles or, to expand the scope, all heavy-duty vehicle axles, which are currently not possible for light household vehicles, can engage or disengage the differential lock while moving, or can achieve both real-time anti-skid and free steering like the Torsen differential.

[0003] The above-mentioned limitations have greatly restricted the ease of application of all-terrain crane products, especially for heavy-loaded and super-large all-terrain cranes, whose operating conditions are complex. Most of the occasions are unpaved roads, and the roads are rugged, and the axles are easily suspended in the air. When it is found that the vehicle needs to be rescued, it is on a slope and it is not easy to hook up. After hooking up, it is difficult to find a suitable occasion for the unhooking operation; if the vehicle is hooked up in advance, the vehicle has already performed multiple steering operations before the differential lock is really needed. This illegal operation will cause damage to the axle.

[0004] In the prior art, a differential lock is used to temporarily lock the differential, prohibiting the differential from working, so that the connected wheels are rigidly connected. As long as one wheel does not slip, there is power output to help the vehicle get out of trouble. Figure 1As shown, taking a two-axle drive axle as an example, the scheme includes a first drive axle and a second drive axle, power is transmitted to the second drive axle by a power distributor 13, and power is input to the input flange of a main reducer 12. The through bridge is composed of a through drive axle inter-axle differential and differential lock 124, an inter-wheel differential and differential lock 123, a wheel side reducer and tire 121, and a wheel side reducer and tire 122. The power is respectively distributed to the main reducer 12 and the main reducer 11 of the second drive axle through the inter-axle differential 124, wherein the power of the second drive axle is evenly distributed to the wheel side reducers and tires 121 and 122 through the inter-wheel differential 123, and the power of the first drive axle is evenly distributed to the wheel side reducers and tires 111 and 112 through the inter-wheel differential 113. When the axle slips, the inter-wheel differential lock or the inter-axle differential lock is combined according to the situation. For example, when the 122 wheel side slips and the whole vehicle loses power, the 124 through-drive axle inter-axle differential and differential lock are ventilated first according to the use conditions. At this time, the vehicle must be stationary, and the air pressure will make the differential lock work. The torque splitting function of the inter-axle differential is prohibited. The 125 half-axle and the 115 half-axle are locked at the same speed, and the first drive axle can still drive the vehicle out of trouble normally. If the 122 and 112 wheel sides slip at the same time, only the 124 through-drive axle inter-axle differential and differential lock are ventilated and the inter-axle differential lock is engaged, but it still cannot be unstuck. It is necessary to ventilate the 113 and 123 wheel inter-wheel differentials and differential locks at the same time and engage the wheel inter-wheel differential lock. At this time, all four wheels are locked together and rotate synchronously, and the power can be output through the 111 and 121 wheels to drive the whole vehicle to move out of trouble.

[0005] However, this solution has the problems of low efficiency of the application of the traditional differential lock mechanism, and the inability to achieve the problem of connecting or disconnecting the axle differential lock while the vehicle is moving. At present, heavy-duty vehicles use the tooth clamp type (forced locking type) differential lock, and the vehicle must be stationary to connect or disconnect; after the differential lock is connected, the steering operation cannot be operated, and the steering operation will generate additional additional force, which will cause the transmission mechanism such as the gear inside the axle to exceed the load and break, damage the axle, or cause irreversible mechanical damage, greatly reducing the service life of the axle; due to the characteristics of the existing differential lock, the driving force or reaction force is easy to exceed the limit of the axle itself, and there is no torque limiting protection function such as slippage, so it cannot be used for a long time, and it is easy to cause damage to the axle due to unexpected circumstances. The above-mentioned usage restrictions are difficult to meet off-road needs, especially for long-body, multi-axis driven heavy-duty all-terrain cranes. Due to the large torque transmitted by heavy-duty vehicles, the torque transmitted from the engine to the axle can reach more than 20,000Nm, and the traditional / existing differential lock mechanism is difficult to transplant to meet the large torque transmission requirements, or it cannot be transplanted and applied due to production costs and layout space limitations. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a drive axle heavy-load driving control system, control method and crane, which can apply braking force to the slipping wheels when the vehicle is traveling off-road at low speed and with heavy load, so that the power can be transmitted to the non-slip wheels to help the vehicle get out of trouble.

[0007] Technical solution: To achieve the above-mentioned purpose, a drive axle heavy-load driving control system described in the present invention includes a vehicle driving system, a braking system circuit that provides braking gas, and a brake air chamber that acts on each axle in the vehicle driving system. A switchable heavy-load anti-skid system is provided between the braking system circuit and the brake air chamber. The heavy-load anti-skid system generates braking force on each axle or each wheel edge through the brake air chamber based on the driving state of each wheel.

[0008] Among them, the heavy-load anti-skid system includes a heavy-load anti-skid controller, an anti-skid control valve corresponding to each axle and a heavy-load anti-skid system wheel speed sensor. The heavy-load anti-skid controller controls the working state of the corresponding anti-skid control valve based on the wheel speed signal collected by the heavy-load anti-skid system wheel speed sensor.

[0009] The heavy-load anti-skid system is switched with the ABS system via an ABS / heavy-load anti-skid system switching valve to communicate with the brake air chamber.

[0010] Among them, the anti-skid control valve includes a pressure reducing valve and two two-position two-way valves P1 and P2, among which the air inlet of P1 is connected to the air tank, and the air outlet is connected to the pressure reducing valve and then divided into two paths, one path is connected to the ABS / heavy-load anti-skid system switching valve, and the other path is connected to the air inlet of P2. The air outlet of P2 leads to the atmosphere, among which P1 is in the normally closed state and P2 is in the normally open state.

[0011] Among them, the ABS system includes an ABS controller, ABS valves corresponding to each axle and an ABS wheel speed sensor. The ABS controller controls the opening and closing of the corresponding ABS valve based on the wheel speed signal collected by the ABS wheel speed sensor. The ABS valve includes an air inlet connected to the braking system circuit, an air outlet connected to the ABS / heavy-load anti-skid system switching valve, and an exhaust port connected to the atmosphere.

[0012] Among them, the braking system circuit includes an air compressor dryer and pressure regulating valve assembly, an air cylinder, a foot valve, and a foot relay valve. The gas output by the air compressor dryer and the pressure regulating valve assembly is stored in the air cylinder. The foot valve is connected to the control port of the air cylinder and the foot relay valve. The air inlet of the foot relay valve is connected to the air cylinder. The air outlet of the foot relay valve is connected to the ABS system to provide an air source for the ABS system. The exhaust port of the foot relay valve is connected to the atmosphere. The air cylinder also provides an air source for the heavy-load anti-skid system.

[0013] The vehicle drive system includes a main reduction gear of the first drive axle, a left wheel reducer assembly and tire of the first drive axle, a right wheel reducer assembly and tire of the first drive axle, a first inter-wheel differential, a first transmission shaft, a main reduction gear of the second drive axle, a left wheel reducer assembly and tire of the second drive axle, a right wheel reducer assembly and tire of the second drive axle, a second inter-wheel differential, an inter-axle differential, a second transmission shaft, and a power distributor; wherein the first transmission shaft connects the first drive axle and the second drive axle, and the second transmission shaft connects the second drive axle. Drive axle and power distributor, power is input into the input flange of the second drive axle, and is respectively distributed to the main reducer of the second drive axle and the main reducer of the first drive axle through the inter-axle differential; the power input into the second drive axle is evenly distributed to the left wheel reducer assembly and tire of the second drive axle, and the right wheel reducer assembly and tire of the second drive axle through the second inter-wheel differential, and the power input into the first drive axle is evenly distributed to the left wheel reducer assembly and tire of the first drive axle, and the right wheel reducer assembly and tire of the first drive axle through the first inter-wheel differential.

[0014] Among them, the first inter-wheel differential, the second inter-wheel differential, and the inter-axle differential are not provided with differential locking mechanisms.

[0015] The control method of the drive axle heavy-load driving control system described in the present invention comprises the following steps:

[0016] (1) The system is turned on in a default state where the heavy-load anti-skid system is not turned on;

[0017] (2) If the driver chooses to start the heavy-load anti-skid system, the heavy-load anti-skid system is detected to see if it has any faults. If so, the startup process is terminated and the default state is restored. If there is no fault, the process proceeds to step (3);

[0018] (3) Check whether the brake gas pressure meets the start-up state. If not, terminate the start-up process and restore to the default state. If it meets the requirements, proceed to step (4).

[0019] (4) Determine whether the vehicle speed reaches or exceeds the minimum critical speed. If so, terminate the startup process and restore to the default state. If not, proceed to step (5);

[0020] (5) The heavy-load anti-skid system is turned on and enters the internal circulation mode: the slip of each wheel is detected regularly. If the speed of the slipping wheel exceeds the specified threshold range, the braking force is adjusted to brake the slipping wheel to achieve the vehicle's escape function.

[0021] A crane described in the present invention comprises the above-mentioned driving axle heavy-load travel control system.

[0022] Beneficial effects: The present invention has the following advantages: 1. The present invention includes an independent and switchable heavy-load anti-skid system. When the vehicle is traveling off-road at a low speed and with a heavy load, the heavy-load anti-skid system is switched to, and the inter-axle differential and the inter-wheel differential are combined to apply braking force to the slipping wheels, so that the power can be transmitted to the non-slipping wheels, thereby increasing the driving performance of the whole vehicle under the condition of losing power due to slippage, helping the vehicle to get out of trouble, thereby solving the problem that the vehicle cannot get out of trouble due to the slipping of the driving axle wheels;

[0023] 2. The heavy-load anti-skid system execution end shares the brake air chamber with the existing ABS system, and cancels the traditional differential lock mechanism. Under the action of the ABS system or the heavy-load anti-skid system, the brake can be engaged and disengaged at any time, solving the limitation that the traditional heavy-load axle differential lock must be statically engaged and disengaged, achieving automatic response and response at any time. The braking force of the brake can be continuously adjustable, and the braking torque is large, so it can be used as a "limited slip differential" without the problem of insufficient output torque. It has a wider range of applications and is more practical.

[0024] 3. The braking torque generated by the brake is safer than the axle gear transmission mechanism. There is no need to worry about the damage to the axle caused by the steering operation during the braking process. This solves the problem that the traditional heavy-load axle does not allow steering when the differential lock is engaged;

[0025] 4. Since the brake caliper can be used for a long time and there is no need to worry about heat generation or damage to the transmission system even if the torque is too large, the performance is better than the traditional friction plate brake. Therefore, the system and the vehicle used in the present invention have reliable performance and simple maintenance, which can solve the problem that the traditional differential lock cannot be used for a long time and long distance, and cannot climb the rugged road with heavy load;

[0026] 5. The maximum pressure of the heavy-load anti-skid system can be set by the pre-calculated maximum safe braking force to ensure that the safety of the axle transmission system used for a long time is not affected, or the service life of the axle gear is not affected;

[0027] 6. This system can further simplify the structure of the axle, reduce the design and production costs of the axle, and is conducive to the design and layout of the axle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the two-axis drive axle system;

[0029] Figure 2 This is a schematic diagram of the heavy-load driving control system of the drive axle of the present invention;

[0030] Figure 3 This is a schematic diagram of the ABS / heavy-load anti-skid system switching valve;

[0031] Figure 4 This is a schematic diagram of an anti-skid control valve;

[0032] Figure 5 It is the logic block diagram of the control strategy based on the drive axle heavy-load driving control system. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below in conjunction with the embodiments and drawings.

[0034] like Figure 1 , 2 As shown, the drive axle heavy-load driving control system described in the present invention is a differential lock control system based on the vehicle braking system. Compared with the mechanical differential lock based on the inter-wheel differential of the axle and the mechanical differential lock based on the inter-axle differential in the prior art, especially for heavy-loaded vehicles, the differential locks used are all clamp-type (forced locking) differential locks. The differential lock needs to be statically mounted and unlocked. Steering operation is not allowed during operation, and the user is not allowed to use it for long distances and for long periods of time. In principle, it is only used for getting out of trouble, and it should be unlocked immediately after getting out of trouble to avoid or reduce mechanical damage to the transmission system caused by the use of the differential lock. That is, the differential lock can be regarded as a consumable product, which is used less each time, and cannot be applied to the off-road conditions of heavy-loaded vehicles, especially all-terrain cranes. The present invention makes full use of the working principle of the differential and uses the brakes on the left and right sides of the axle to complete the differential locking function.

[0035] The drive axle heavy-load driving control system specifically includes a vehicle drive system, an air-circuit braking system (including a braking system circuit and a braking air chamber), an ABS system, a heavy-load anti-skid system, a master controller, and an ABS / heavy-load anti-skid system switching valve (the right ABS / heavy-load anti-skid system switching valve 415 of the first drive axle, the left ABS / heavy-load anti-skid system switching valve 416 of the first drive axle, the right ABS / heavy-load anti-skid system switching valve 419 of the second drive axle, and the left ABS / heavy-load anti-skid system switching valve 420 of the second drive axle). Among them, the ABS system is connected between the braking system circuit and the braking air chamber, and the ABS / heavy-load anti-skid system switching valve port 1 and port 2 are respectively connected to the heavy-load anti-skid system and the ABS system, and the port 3 is connected to the braking air chamber of the air-circuit braking system. Figure 3 By switching the ABS / heavy-load anti-skid system switching valve, the brake system circuit is connected to the brake air chamber through the ABS system or the heavy-load anti-skid system is connected to the brake air chamber, and the heavy-load anti-skid system is provided with air source by the air reservoir.

[0036] The ABS system and the heavy-load anti-skid system are independent of each other, but the execution end shares the brake air chamber. To ensure the independence of the two systems, the present invention utilizes an ABS / heavy-load anti-skid system switching valve to switch between the two systems. Specifically, when the system detects that the vehicle speed exceeds a safety threshold, the heavy-load anti-skid system is forced to exit; when the vehicle needs to be heavily loaded for off-road driving, the heavy-load anti-skid system control button needs to be turned on, and the heavy-load anti-skid system starts to work when the vehicle speed needs to be guaranteed to be within the set safety speed. The ABS / heavy-load anti-skid systems do not interfere with each other during use and complement each other.

[0037] The vehicle drive system includes the main reduction gear 11 of the first drive axle, the left wheel side reduction gear assembly and tire 111 of the first drive axle, the right wheel side reduction gear assembly and tire 112 of the first drive axle, the first inter-wheel differential 113, the first transmission shaft 115, the main reduction gear 12 of the second drive axle, the left wheel side reduction gear assembly and tire 121 of the second drive axle, the right wheel side reduction gear assembly and tire 122 of the second drive axle, the second inter-wheel differential 123, the inter-axle differential 124, the second transmission shaft 125, and the power distributor 13. Among them, the first transmission shaft 115 connects the first drive axle and the second drive axle, the second transmission shaft 125 connects the second drive axle and the power distributor 13, the power is input to the input flange of the second drive axle, and is respectively distributed to the main reduction gear 12 of the second drive axle and the main reduction gear 11 of the first drive axle through the inter-axle differential 124. The power input to the second drive axle is evenly distributed to the left wheel reducer assembly and tire 121 of the second drive axle, and the right wheel reducer assembly and tire 122 of the second drive axle through the second inter-wheel differential 123. The power input to the first drive axle is evenly distributed to the left wheel reducer assembly and tire 111 of the first drive axle, and the right wheel reducer assembly and tire 112 of the first drive axle through the first inter-wheel differential 113.

[0038] The first inter-wheel differential 113, the second inter-wheel differential 123 and the inter-axle differential 124 are not provided with differential locking mechanisms. The power distributor 13 includes a transfer case, a motor and other power sources.

[0039] The air circuit brake system includes a brake system circuit and a brake air chamber, wherein the brake system circuit includes an air compressor dryer and a pressure regulating valve assembly 211, an air reservoir 212, a foot valve 213, and a foot relay valve 214, and the brake air chamber includes a left brake air chamber 317 of the first drive axle, a right brake air chamber 318 of the first drive axle, a left brake air chamber 321 of the second drive axle, and a right brake air chamber 322 of the second drive axle. Among them, the foot valve 213 is arranged in the cab, connected by a foot brake pedal, and includes a motion sensor. When the driver needs to brake, he will step on the foot brake pedal to brake, thereby driving the valve core of the foot valve 213 to move. Port 1 of the foot valve 213 is connected to the air outlet of the air reservoir 212, and port 2 is connected to the control port 4 of the foot relay valve 214. This air circuit is a control air circuit, which is usually connected by a thinner pipe. The air reservoir 212 is used to store the gas output by the air compressor dryer and the pressure regulating valve assembly 211, and air reservoirs of different sizes will be arranged in multiple places of the vehicle as needed to provide a gas power source.

[0040] The foot relay valve 214 is usually arranged close to the brake air chamber, with its air inlet 1 connected to the nearby air reservoir 212; the air outlet 2 connected to the ABS system; the exhaust port 3 connected to the atmosphere, and the gas is discharged from port 3 when it needs to be emptied; the control port 4 controls the opening and closing of the air circuits between ports 1 and 2, and between ports 2 and 3. When the driver switches to the ABS system function through the ABS / heavy-load anti-skid system switching valve, the brake pedal is stepped on, which will open the valve core of the foot valve 213, and control the gas to enter the 4th port of the foot relay valve from the 2nd port of the foot valve 213. At this time, the 1st port to the 2nd port of the foot relay valve 214 is connected, and the 2nd port is disconnected from the 3rd port. The brake gas enters the brake air chamber (the left brake air chamber 317 of the first drive axle, the right brake air chamber 318 of the first drive axle, the left brake air chamber 321 of the second drive axle or the right brake air chamber 322 of the second drive axle) through the 1st port to the 2nd port, and then pushes the brake in the corresponding brake air chamber to generate braking force on the axle. When the foot brake pedal is released, the foot valve 213 is de-energized, the 1st port to the 2nd port of the foot relay valve 214 is disconnected, and the 2nd port is connected to the 3rd port. The gas in the brake air chamber is discharged to the atmosphere from the passage from the 2nd port to the 3rd port in the opposite direction.

[0041] The ABS system includes an ABS controller 31, a first ABS valve 311, a second ABS valve 312, a third ABS valve 313, a fourth ABS valve 314, a first drive axle left ABS wheel speed sensor 315, a first drive axle right ABS wheel speed sensor 316, a second drive axle left ABS wheel speed sensor 319, and a second drive axle right ABS wheel speed sensor 320. Among them, one port of the first ABS valve 311, the second ABS valve 312, the third ABS valve 313, and the fourth ABS valve 314 are all connected to the air outlet 2 of the foot relay valve 214 (that is, the air outlet 2 of the foot relay valve 214 is respectively connected to one port of the first ABS valve 311, the second ABS valve 312, the third ABS valve 313, and the fourth ABS valve 314 through a one-to-four air pipe), and two ports of the first ABS valve 311, the second ABS valve 312, the third ABS valve 313, and the fourth ABS valve 314 are respectively connected to two ports of the right side ABS / heavy-load anti-skid system switching valve 415 of the first drive axle, the left side ABS / heavy-load anti-skid system switching valve 416 of the first drive axle, the right side ABS / heavy-load anti-skid system switching valve 419 of the second drive axle, and the left side ABS / heavy-load anti-skid system switching valve 420 of the second drive axle; three ports of the first ABS valve 311, the second ABS valve 312, the third ABS valve 313, and the fourth ABS valve 314 are connected to the atmosphere. That is, the ABS valve is an air circuit control valve, and its solenoid valve control end is connected to the ABS controller 31, port 1 is the air inlet, port 2 is the air outlet, and port 3 is connected to the atmosphere. When disconnected, the gas in the brake air chamber is discharged from port 3 to the atmosphere through port 2 in the reverse direction.

[0042] The three ports of the first drive axle right ABS / heavy-load anti-skid system switching valve 415, the first drive axle left ABS / heavy-load anti-skid system switching valve 416, the second drive axle right ABS / heavy-load anti-skid system switching valve 419, and the second drive axle left ABS / heavy-load anti-skid system switching valve 420 are respectively connected to the first drive axle right brake air chamber 318, the first drive axle left brake air chamber 317, the second drive axle right brake air chamber 322, and the second drive axle left brake air chamber 321. One port of the first drive axle right brake air chamber 318, the first drive axle left brake air chamber 317, the second drive axle right brake air chamber 322, and the second drive axle left brake air chamber 321 is connected to the heavy-load anti-skid system. The ABS / heavy-load anti-skid system switching valve is a two-position three-way solenoid valve. When the ABS / heavy-load anti-skid system switching valve is not powered, the brake system circuit is directly connected to the brake air chamber through the ABS system. When powered or manually switched to the heavy-load anti-skid system, the heavy-load anti-skid system is connected to the brake air chamber.

[0043] The ABS / heavy-load anti-skid system switching valve can realize the switching between the ABS function and the heavy-load anti-skid function mode of the whole vehicle. The working conditions of the two modes do not overlap. The ABS function is mainly used when the vehicle is running at high speed to avoid wheel locking during emergency braking or braking on low-adhesion roads. The heavy-load anti-skid function is mainly used in low-speed off-road conditions. The ABS / heavy-load anti-skid system switching valve is controlled by the main controller 21 to prevent the heavy-load anti-skid control system from affecting the ABS system or the whole vehicle braking system.

[0044] The left ABS wheel speed sensor 315 of the first driving axle, the right ABS wheel speed sensor 316 of the first driving axle, the left ABS wheel speed sensor 319 of the second driving axle, and the right ABS wheel speed sensor 320 of the second driving axle respectively monitor the rotation speed of the wheels on the left side of the first driving axle, the right side of the first driving axle, the left side of the second driving axle, and the right side of the second driving axle, and transmit the signal to the ABS controller 31. The ABS controller 31 receives the signals from each wheel speed sensor (the left ABS wheel speed sensor 315 of the first driving axle, the right ABS wheel speed sensor 316 of the first driving axle, the left ABS wheel speed sensor 319 of the second driving axle, and the right ABS wheel speed sensor 320 of the second driving axle), and controls the opening and closing of the corresponding ABS valve according to these signals. Specifically, the ABS controller 31 obtains the rotation speed signal of each wheel, determines whether the corresponding wheel has a brake lock according to the wheel speed signal, and if so, the brake air chamber pressure can be continuously adjusted by releasing the brake air chamber pressure by opening and closing the ABS valve corresponding to the wheel, so that the slip amount of each wheel is within the control range to prevent the wheel from locking, but it is mainly used in high-speed conditions, and its system does not work after the vehicle speed is lower than a certain speed.

[0045] The heavy-load anti-skid system includes a heavy-load anti-skid controller 41, a first anti-skid control valve 411, a second anti-skid control valve 412, a third anti-skid control valve 413, a fourth anti-skid control valve 414, a first drive axle right side heavy-load anti-skid system wheel speed sensor 417, a first drive axle left side heavy-load anti-skid system wheel speed sensor 418, a second drive axle right side heavy-load anti-skid system wheel speed sensor 421, and a second drive axle left side heavy-load anti-skid system wheel speed sensor 422.

[0046] like Figure 4As shown, the anti-skid control valve (the first anti-skid control valve 411, the second anti-skid control valve 412, the third anti-skid control valve 413, and the fourth anti-skid control valve 414) includes two two-position two-way valves P1 (411a), P2 (411c), and a pressure reducing valve 411c. Among them, one end of the two-position two-way valve P1 is used as the 1st port of the anti-skid control valve, connected to the air reservoir, and the setting of the one-way valve in P1 can avoid the problem of the pressure drop of the brake air chamber when the pressure of the brake air chamber is higher than the pressure of the air reservoir; the air reservoir can be the air reservoir 212 in the brake system circuit, or an air reservoir arranged separately. The other end of the two-position two-way valve P1 is divided into two paths through the pressure reducing valve, one of which is used as the 2nd port of the anti-skid control valve, connected to the ABS / heavy-load anti-skid system switching valve, and the other is connected to one end of the two-position two-way valve P2, and the other end of the two-position two-way valve P2 is used as the 3rd port of the anti-skid control valve, leading to the atmosphere. Port 4 of the anti-skid control valve is the control port of the solenoid valve of the two-position two-way valve P1P2. The two-position two-way valve P1 is in a normally closed state, and the two-position two-way valve P2 is in a normally open state.

[0047] When the anti-skid control system is not working, the two solenoid valves P1 and P2 are not energized, port 1 and port 2 of the anti-skid control valve are isolated, port 3 and port 2 are connected, and the air pressure of the air reservoir is isolated. Since port 2 is connected to the brake air chamber through the ABS / heavy-load anti-skid system switching valve, the air pressure of the brake air chamber is directly connected to the atmosphere, thereby ensuring that if the heavy-load anti-skid system fails or the solenoid valve in the anti-skid control valve fails, the brake air chamber will be locked due to residual gas; when the anti-skid control system is started, when the brake air chamber needs to be inflated, P2 is energized, the connection between port 2 and port 3 is cut off, P1 is energized, port 1 and port 2 are connected, and the air reservoir directly supplies air to the brake air chamber. If the air pressure in the air chamber is higher than the air pressure in the air reservoir, the air pressure in the air chamber is maintained; when the brake air chamber needs to be deflated, P1 is de-energized, P2 is de-energized, the air pressure supply of the air reservoir is cut off, the connection between the brake air chamber and the atmosphere is connected, and the air pressure in the brake air chamber is discharged.

[0048] When P1 and P2 are powered on, the gas in the air tank enters the pressure reducing valve through port 1. The pressure reducing valve controls the pressure within the safety threshold range based on calculations to prevent excessive braking force from causing overload of the axle transmission system and premature damage to the axle. The decompressed gas enters the brake air chamber from port 2 to generate braking force. When the braking force needs to be released or reduced, the heavy-duty anti-skid controller will control P2 to power off or temporarily power off to discharge the air in the brake air chamber to the atmosphere through port 3. At the same time, it controls the power off of port P1 to disconnect from the gas source. The pressure reducing valve can set the pressure value according to demand.

[0049] When the anti-skid control valve is not powered, the air source is separated from the brake air chamber, and the ABS / heavy-duty anti-skid system switching valve forms a double insurance to prevent the gas in the air reservoir from directly communicating with the brake air chamber, which would cause a safety hazard. It contains a pressure reducing valve (adjustable or pre-set) to limit the brake pressure entering the air chamber to prevent excessive braking force from damaging the axle gear system.

[0050] The wheel speed sensor 417 of the heavy-load anti-skid system on the right side of the first drive axle, the wheel speed sensor 418 of the heavy-load anti-skid system on the left side of the first drive axle, the wheel speed sensor 421 of the heavy-load anti-skid system on the right side of the second drive axle, and the wheel speed sensor 422 of the heavy-load anti-skid system on the left side of the second drive axle respectively monitor the rotation speed of the wheels on the right side of the first drive axle, the left side of the first drive axle, the right side of the second drive axle, and the left side of the second drive axle, and transmit the signal to the heavy-load anti-skid controller 41. The heavy-load anti-skid controller 41 calculates whether the wheel is in slip or normal operation during the vehicle's travel based on the wheel speed signal, and can control the wheel speed of the slipping wheel according to the set algorithm to ensure that the vehicle power system fully utilizes the ground adhesion and improves the off-road performance of the vehicle. Specifically: the heavy-load anti-skid control valve is arranged between the air reservoir and the brake air chamber, and the connection between the air reservoir and the brake air chamber can be opened through the heavy-load anti-skid control valve to control the single brake air chamber to generate braking force. The heavy-load anti-skid controller senses wheel slippage through the wheel speed sensor arranged on the drive axle. At this time, the heavy-load anti-skid control valve can be used to generate braking force on the corresponding vehicle. Due to the existence of the inter-axle differential and the inter-wheel differential, the principle is used to enable other wheels to output power to help the vehicle out of trouble.

[0051] The master controller 21 is connected to the ABS controller and the heavy-duty anti-skid controller, and is connected to the vehicle control system. In addition to interacting with the ABS controller, it can also interact with the heavy-duty anti-skid controller and transmit vehicle-related information to the heavy-duty anti-skid controller, such as the pressure of each suspension cylinder, the stroke of the suspension cylinder, the engine speed, the engine output torque, the gear position of the transmission, the gear position of the transfer case, the pressure of the air circuit system, the ABS wheel speed sensor and other information.

[0052] When the heavy-load anti-skid system works, the braking system switches to the heavy-load anti-skid circuit. When the heavy-load anti-skid system does not work or the driver steps on the brake (there is a sensor on the foot valve), the system switches to the normal braking circuit to ensure driving safety.

[0053] Based on the above drive axle heavy-load driving control system, the present invention also provides a control strategy for starting a heavy-load anti-skid system, such as Figure 5 As shown, specifically:

[0054] S1: The system is in the default state when it is turned on without turning on the heavy-load anti-skid system, that is, the normal braking system state with the ABS system involved;

[0055] S2: The driver chooses whether to turn on the heavy-load anti-skid system: if not, the system returns to the default state of S1; if yes, the system enters S3;

[0056] S3: The system starts the self-checking procedure to determine the starting conditions of the heavy-load anti-skid system;

[0057] S4: Check whether the heavy-load anti-skid system has a fault. If there is a fault, enter S7 (prompt display: "Heavy-load anti-skid system fault", end the startup process), and then restore to the default state. If there is no fault, enter S5;

[0058] S5: Check whether the system brake air pressure meets the start-up state. If not, enter S7 (prompt display: "Brake air pressure is too low", end the startup process), restore to the default state, and enter S6 if there is no fault;

[0059] S6: Determine whether the vehicle speed reaches or exceeds the minimum critical speed of ABS and other related systems. In principle, the heavy-load anti-skid system is only used in low-speed areas to ensure driving safety. If the speed exceeds the specified speed, enter S7 (prompt display: "Driving speed is too high", end the startup process), restore to the default state, and enter S8 if there is no fault;

[0060] S7: The display prompts relevant information according to the needs, exits the startup of the heavy-load anti-skid system, and restores the default state;

[0061] S8: The system starts the heavy-load anti-skid system, and the system interface displays: "Heavy-load anti-skid system has been started";

[0062] S9: The heavy-load anti-skid system enters the internal circulation mode (continuously detecting tire slippage and continuously applying a certain limit of braking to the slipping tires to achieve the escape function), obtains information such as vehicle speed, wheel speed of each driving axle, brake system air pressure, suspension cylinder pressure, etc., and processes the information;

[0063] S10: Calculate the slipping wheel or the slipping axle, the required braking torque, etc. within a cyclic control period;

[0064] S11: Determine whether the speed of the slipping wheel exceeds a specified threshold range. If the driving wheel does not exceed the threshold range, the control is not performed and the next calculation cycle is entered. If the driving wheel does exceed the threshold range, the control is performed in the next step.

[0065] S12: Control the brake of the slipping wheel and adjust the braking force to control the wheel to reach the required threshold range;

[0066] S13: Increase the braking force or reduce the braking force to ensure that the slip rate of the driving wheels is within the control range.

[0067] The present invention further explains the working principle of the differential based on the above-mentioned drive axle heavy-load driving control system:

[0068] According to the torque distribution principle of the differential: when the adhesion of one wheel side is 0, the wheel output torque is 0, and the output torque of the entire bridge is 0. At this time, the brake can be used to brake on one side and apply a certain torque to the wheel side with low adhesion. Assume that this braking torque is in is the load borne by a single tire, is the ground adhesion coefficient on the side with high adhesion. The total input torque of the axle at this time The output torque on the high adhesion road side is:

[0069]

[0070] Ground adhesion coefficient utilization rate: 100%;

[0071] According to the differential principle of the differential: by controlling the rotation speed of the left and right half shafts, the purpose of brake torque control can be achieved, that is, controlling the wheel speed on the low-adhesion side to be equal to or close to the wheel speed on the high-adhesion side can fully utilize the ground adhesion coefficient and greatly improve the off-road performance of the vehicle:

[0072]

[0073] Among them, n 1 -Speed ​​of the left wheel half shaft; n 2 -Right side axle shaft speed; n 0 -Differential case input speed.

[0074] The working principle of the differential in the prior art is as follows:

[0075] The differential principle of the traditional planetary gear differential:

[0076] n 1 +n 2 =2n 0 ,

[0077] Where: n 1 -Speed ​​of the left wheel half shaft; n 2 -Right side axle shaft speed; n 0 -Differential case input speed.

[0078] It can be seen that:

[0079] When the speed of the half-shaft gears on both sides is the same, the differential does not work at all; 1 ≠n 2When the planetary gear in the differential rotates at the corresponding speed, the half-axles on both sides of the wheel can rotate at different speeds, perfectly adapting to the uneven speed of the left and right wheels such as turning, so that the wheels are always in a pure rolling state relative to the ground; when n 0 When = 0, the half shaft on one side of the wheel rotates forward, and the half shaft on the other side of the wheel rotates reversely at the same speed.

[0080] Torque distribution principle of traditional planetary gear differential:

[0081] Since the radius of the left and right planetary gears is equal, its structure is essentially similar to an equal-arm lever, which always transfers the torque M 0 Distribute equally to the left and right semi-axes:

[0082] M 1 =M 2 =M 0 / 2,

[0083] That is, the output torque of the wheel side determines the input torque. When one side of the tire slips on the ground, the output torque is 0, and the input torque on the other side of the differential is also 0, the power of the whole vehicle cannot be output, and the input torque is also 0.

[0084] The above-mentioned drive axle heavy-load driving control system makes full use of the working principle of the differential and applies the brakes on the axle to achieve the escape function. Specifically, when the vehicle is driving normally, due to the uneven road and the vehicle turning, the track lengths of each wheel traveling at the same time will be different. If there is no differential, the tires will slip and cause abnormal tire wear. However, when one or more wheels slip, the existence of the differential (differential principle) will cause the vehicle to have no power output. By controlling the rotation speed of the slipping wheel through the brake, and applying the differential principle, power can be output to the non-slipping drive wheel, thereby getting the vehicle out of trouble. If the vehicle is escaped by locking with a traditional tooth-type differential lock, the vehicle is not allowed to turn due to principle limitations, which greatly limits the use environment of the traditional differential lock and reduces vehicle efficiency.

[0085] The brakes in this system can be engaged or disengaged instantly, breaking the limitation that traditional heavy-duty axle differential locks can only be engaged or disengaged when the vehicle is stationary, and achieving automatic and instant response. Since the braking force of the brake can be continuously adjusted and has a large braking torque, it is equivalent to a "limited slip differential", which effectively solves the problem of insufficient output torque.

[0086] In addition, the braking torque generated by the brakes is safer for the axle gear transmission mechanism, and there is no need to worry about damage to the axle caused by steering during braking. This solves the problem of prohibiting steering when the differential lock is engaged for traditional heavy-loaded axles. At the same time, the brake caliper can be used for long-term friction, and even in the case of slippage caused by excessive torque, there is no need to worry about overheating or damage to the transmission system. Its performance is better than that of traditional friction plate brakes.

[0087] Patent CN 117103984A discloses a chassis transmission system and a control method thereof, which adds a limited-slip differential lock mechanism to the traditional main reducer, and at the same time, by arranging an ABS speed sensor on the wheel, a slope acceleration sensor on the main reducer, and a strain gauge on the support shaft of the wheel assembly, when the sensor detects torque overload, the speed limiter is allowed to slip, so that the entire transmission system will not exceed the torque limit value of the torquer, thereby protecting the entire axle from damage after overload. This limited-slip differential lock can not only ensure that the vehicle will not be damaged when overloaded, but also ensure that the vehicle has a certain driving ability. However, since the limited-slip differential cannot meet the long-term friction, and has a complex structure and high cost, and the limited-slip differential locking mechanism is a multi-plate wet brake, it requires a separate oil circuit control and a separate set of heat dissipation mechanisms.

[0088] Compared with the system and method disclosed in the patent, the brake caliper described in this system can be used for friction for a long time. Even if the torque is too large and causes slippage, there is no need to worry about overheating or damage to the transmission system. Its performance is better than that of traditional friction plate brakes.

[0089] The above-mentioned drive axle heavy-load driving control system and vehicles such as cranes using the system are simple to maintain and have high reliability, and effectively solve the problem that traditional differential locks cannot be used for a long time and long distance.

[0090] Compared with the limitation of the traditional differential lock which is only used as an escape mechanism and is not suitable for frequent use, the present invention can be used as a device for off-road vehicles under normal adhesion conditions, and is particularly suitable for heavy-load climbing requirements on rugged roads.

[0091] In this embodiment, based on the above-mentioned drive axle heavy-load driving control system, the traditional differential locking mechanism can be further retained as a safety backup. The heavy-load anti-skid system can also be integrated into the ABS system or other systems for sharing, or the heavy-load anti-skid system can also be made into an automatically executed device.

Claims

1. A heavy-load driving control system for a drive axle, comprising a vehicle drive system, a brake system circuit for providing brake gas, and a brake air chamber acting on each axle in the vehicle drive system, characterized in that: A switchable heavy-load anti-skid system is provided between the brake system circuit and the brake air chamber. The heavy-load anti-skid system generates a braking force on each axle or each wheel edge through the brake air chamber based on the driving state of each wheel.

2. The drive axle heavy-load driving control system according to claim 1, characterized in that: The heavy-load anti-skid system comprises a heavy-load anti-skid controller (41), an anti-skid control valve corresponding to each axle, and a heavy-load anti-skid system wheel speed sensor. The heavy-load anti-skid controller (41) controls the working state of the corresponding anti-skid control valve based on the wheel speed signal collected by the heavy-load anti-skid system wheel speed sensor.

3. The drive axle heavy-load driving control system according to claim 1, characterized in that: The heavy-load anti-skid system is switched with the ABS system via an ABS / heavy-load anti-skid system switching valve to communicate with the brake air chamber.

4. The drive axle heavy-load driving control system according to claim 3, characterized in that: The anti-skid control valve includes a pressure reducing valve and two two-position two-way valves P1 and P2, wherein the air inlet of P1 is connected to an air tank, and the air outlet is connected to the pressure reducing valve and then divided into two paths, one path is connected to the ABS / heavy-load anti-skid system switching valve, and the other path is connected to the air inlet of P2. The air outlet of P2 leads to the atmosphere, wherein P1 is in a normally closed state and P2 is in a normally open state.

5. The drive axle heavy-load driving control system according to claim 3, characterized in that: The ABS system comprises an ABS controller (31), an ABS valve corresponding to each axle, and an ABS wheel speed sensor. The ABS controller (31) controls the opening and closing of the corresponding ABS valve based on the wheel speed signal collected by the ABS wheel speed sensor. The ABS valve comprises an air inlet connected to a brake system circuit, an air outlet connected to an ABS / heavy load anti-skid system switching valve, and an exhaust port connected to the atmosphere.

6. The drive axle heavy-load driving control system according to claim 3, characterized in that: The brake system circuit comprises an air compressor dryer and pressure regulating valve assembly (211), an air storage cylinder (212), a foot valve (213), and a foot relay valve (214); the gas output by the air compressor dryer and pressure regulating valve assembly (211) is stored in the air storage cylinder (212); the foot valve (213) is connected to the control ports of the air storage cylinder (212) and the foot relay valve (214); the air inlet of the foot relay valve (214) is connected to the air storage cylinder (212); the air outlet of the foot relay valve (214) is connected to the ABS system to provide an air source for the ABS system; the air outlet of the foot relay valve (214) is connected to the atmosphere; and the air storage cylinder (212) also provides an air source for a heavy-load anti-skid system.

7. The drive axle heavy-load driving control system according to claim 1, characterized in that: The vehicle drive system comprises a main reduction gear (11) of a first drive axle, a left wheel-side reduction gear assembly and a tire (111) of the first drive axle, a right wheel-side reduction gear assembly and a tire (112) of the first drive axle, a first inter-wheel differential (113), a first transmission shaft (115), a main reduction gear (12) of a second drive axle, a left wheel-side reduction gear assembly and a tire (121) of the second drive axle, a right wheel-side reduction gear assembly and a tire (122) of the second drive axle, a second inter-wheel differential (123), an inter-axle differential (124), a second transmission shaft (125), and a power distributor (13); wherein the first transmission shaft (115) connects the first drive axle and the second drive axle, and the second transmission shaft (125) 125) connects the second drive axle with the power distributor (13), the power is input into the input flange of the second drive axle, and is respectively distributed to the main reducer (12) of the second drive axle and the main reducer (11) of the first drive axle through the inter-axle differential (124); the power input into the second drive axle is evenly distributed to the left wheel side reducer assembly and tire (121) of the second drive axle, and the right wheel side reducer assembly and tire (122) of the second drive axle through the second inter-wheel differential (123), and the power input into the first drive axle is evenly distributed to the left wheel side reducer assembly and tire (111) of the first drive axle, and the right wheel side reducer assembly and tire (112) of the first drive axle through the first inter-wheel differential (113).

8. The drive axle heavy-load driving control system according to claim 7, characterized in that: The first inter-wheel differential (113), the second inter-wheel differential (123), and the inter-axle differential (124) are not provided with differential locking mechanisms.

9. A control method for a drive axle heavy-load driving control system as claimed in claim 1, characterized in that: The following steps are involved: (1) The system is turned on in a default state where the heavy-load anti-skid system is not turned on; (2) If the driver chooses to start the heavy-load anti-skid system, the heavy-load anti-skid system is detected to see if it has any faults. If so, the startup process is terminated and the default state is restored. If there is no fault, the process proceeds to step (3); (3) Check whether the brake gas pressure meets the start-up state. If not, terminate the start-up process and restore to the default state. If it meets the requirements, proceed to step (4). (4) Determine whether the vehicle speed reaches or exceeds the minimum critical speed. If so, terminate the startup process and restore to the default state. If not, proceed to step (5); (5) The heavy-load anti-skid system is turned on and enters the internal circulation mode: the slip of each wheel is detected regularly. If the speed of the slipping wheel exceeds the specified threshold range, the braking force is adjusted to brake the slipping wheel to achieve the vehicle's escape function.

10. A crane, characterized in that: It includes the drive axle heavy-load running control system as described in any one of claims 1-8.

Images