Pressure loss protection brake device

Abstract

The utility model relates to the technical field of crawler tractors, in particular to a decompression protection brake device which comprises a gearbox, brakes, a driving shaft and an oil tank, each brake comprises a shell, a fixed piston, a movable piston, a compression spring, a brake releasing bolt, a middle baffle, a pressing disc and a friction disc assembly, and a loading oil cavity of each brake is connected with a hydraulic oil tank through an oil way. And a pump and an electromagnetic directional valve are arranged on the oil path. According to the hydraulic electromagnetic valve for braking control, a braking system can be controlled according to different braking intentions, various braking requirements of driving and parking are met, the response speed is high, and safety and reliability are achieved; and brake pressure loss protection can be carried out in emergency situations or vehicle faults, the safety of the vehicle and a driver is protected, the safety performance is higher, and the device is suitable for being used in large-slope areas such as mountains and hills.

Description

TECHNICAL FIELD

[0001] The utility model relates to a tracked tractor technical field, specifically is a pressure loss protection braking device. BACKGROUND

[0002] The currently common tracked chassis is mainly composed of a hydraulic mechanical combined type walking system, is composed by a single HST speed changer and a mechanical gearbox, and transmits torque and brakes by a clutch and a friction plate. The tracked chassis is commonly used in small and medium-sized tracked tractors, harvesters and other agricultural machinery in China due to its simple and reliable structure, easy maintenance and low cost and other advantages.

[0003] In hilly and mountainous areas such as Yunnan, Guizhou and Hunan, tracked tractors gradually begin to replace manual work and are matched with various small agricultural implements to plow, rotary till, ridge, cellar, pond, fertilize, film, transplant, water, plant protection, film, stalk, transport and other operations. The hilly and mountainous areas have rugged and uneven terrain, large slope and complex working environment, and users have higher safety requirements for tractors. When the tractor suddenly fails in hydraulic pressure or power during use and cannot operate normally, the tractor must be able to perform emergency braking in any operating scenario and have reliable braking performance to ensure the safety of the operating machinery and especially the driver.

[0004] Based on the above factors, it is necessary to provide a braking device with high safety performance and good reliability under normal operation or sudden conditions and a control method.

[0005] The prior art has disclosed some braking devices for tracked tractors, such as the utility model patent "Braking device and tractor" applied for by the State Intellectual Property Office on April 13, 2021, and authorized with the announcement number CN201911251591.9. The braking device of the patent comprises: a mounting disc for fixed connection with a half shaft tube outside a rotating shaft; a friction plate fixedly installed on the mounting disc; a friction dynamic plate matched with the friction plate to realize braking; a cover plate fixedly connected with the mounting disc and accommodating the friction plate and the friction dynamic plate therein; a through hole through which the rotating shaft for installing the braking device passes among the mounting disc, the friction plate, the friction dynamic plate and the cover plate, and is fixedly connected with the hub mounting disc outside; a first oil seal is arranged between the mounting disc and the rotating shaft; and a second oil seal is arranged between the cover plate and the rotating shaft. The patent also provides a tractor. The braking device and the tractor provided by the patent can form a closed environment in the braking device, play a role in preventing water, sand and dust, and improve the service life of the braking device. However, the braking device in the above patent cannot provide pressure loss protection braking.

[0006] The utility model patent "A valve group, tractor braking system and tractor" applied for by the State Intellectual Property Office on August 30, 2021, has the authorization announcement number CN202122059362.6. The valve group of this patent includes a logic valve and a switching valve; the logic valve has a first valve core, a first oil outlet, and two first oil inlets. When oil is fed into a single first oil inlet, the first valve core moves to close the passage between the first oil inlet and the first oil outlet and to open the passage between the other first oil inlet and the first oil outlet, or when oil is fed into both first oil inlets, the first valve core moves to connect both first oil inlets with the first oil outlet; the switching valve has a second valve core, a second oil outlet, and two second oil inlets. When oil is fed into a single second oil inlet, the second valve core moves to open the passage between the second oil inlet and the second oil outlet and to block the passage between the other second oil inlet and the second oil outlet, or when oil is fed into both second oil inlets, the second valve core moves to connect both second oil inlets with the second oil outlet. Its structure is simple. However, this patent mainly designs the control mechanism of the brake device and does not involve the structure of the pressure loss protection brake device.

[0007] The State Intellectual Property Office filed a utility model patent application on February 5, 2015, titled "A Braking Device and a Method for Operating a Braking Device for an Automatic Parking Brake," with authorization publication number CN201510060146.X. The patent describes a braking device for an automatic parking brake comprising a brake caliper housing having an internal cavity for accommodating a fluid; a brake piston axially displaceable along an axis within the caliper housing; and a plunger displaceable coaxially with the brake piston within the caliper housing. The patent also describes a braking device configured such that the plunger can hydraulically transmit force to the brake piston via the fluid within the internal cavity of the caliper housing and mechanically transmit force to the brake piston, wherein the plunger can transmit force to the brake piston via a spindle and a spindle nut. However, the patent does not address the braking device's pressure-loss protection function. Utility Model Content

[0008] In response to the problems raised in the background technology, the purpose of the present utility model is to propose a brake device with pressure loss protection, which adopts wet multi-plate brake friction disc braking, and the brake control system is controlled by a hydraulic brake solenoid valve. The brake system can be controlled according to different braking intentions to meet various driving and parking braking requirements, with fast response speed, safety and reliability; and can realize brake pressure loss protection in the event of an emergency or vehicle failure, with higher safety performance, and is suitable for use in mountainous and hilly areas with large slopes.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] A pressure loss protection braking device comprises: a gearbox, a brake, a drive shaft, and a fuel tank. The gearbox has two sets of differential steering planetary assemblies, and the input shaft of the gearbox is connected to a drive shaft through the two sets of differential steering planetary assemblies. The outer surface of each drive shaft at one end connected to the corresponding differential steering planetary assembly is provided with a first spline, and each drive shaft is connected to a brake through the first spline.

[0011] The brake comprises a housing, a fixed piston, a movable piston, a compression spring, an intermediate baffle, a pressure plate, and a friction plate assembly; the housing is sleeved on the drive shaft, one end of the housing is connected to the outer shell of the gearbox, and the other end of the housing has an annular sealing plate, the middle of the annular sealing plate has a first axial through hole, and the outer periphery of the first axial through hole has a fourth axial through hole;

[0012] The fixed piston is an annular structure as a whole. The fixed piston is installed in the middle of the inner cavity of the housing, dividing the inner cavity of the housing into a piston cavity and a drive cavity. The drive cavity is located between the piston cavity and the outer shell. The intermediate baffle, pressure plate and friction plate assembly are all installed in the drive cavity. The friction plate assembly is slidably connected to the first spline on the drive shaft. One end of the movable piston is installed in the piston cavity, and the other end extends through the fixed piston to the drive cavity. An oil loading chamber is provided between the movable piston and the fixed piston.

[0013] The compression spring is evenly distributed between the moving piston and the annular sealing plate. The elastic force of the compression spring presses the pressure plate and the friction plate assembly toward the middle baffle through the moving piston, so that the friction plate assembly is compressed to produce braking;

[0014] The loading oil chamber of each brake is connected to the hydraulic oil tank through an oil circuit. The oil circuit is equipped with a pump and an electromagnetic reversing valve, which is connected to the vehicle ECU. When oil is added to the loading oil chamber, the oil pressure causes the movable piston to move toward the annular sealing plate, thereby releasing the brake.

[0015] The movable piston as a whole is a two-step shaft structure composed of a first step shaft and a second step shaft, and the middle part of the movable piston is provided with a third axial through hole penetrating the first step shaft and the second step shaft, and the outer periphery of the third axial through hole is provided with a second axial through hole; the third axial through hole of the movable piston is sleeved on the drive shaft, the first step shaft is slidably connected to the inner hole of the fixed piston, and the second step shaft is slidably connected to the piston cavity of the housing; the free end of the first step shaft extends into the drive cavity of the housing through the inner hole of the fixed piston; the space between the second step shaft and the fixed piston is used as a loading oil chamber.

[0016] A brake release bolt is provided in the second axial through hole of the movable piston, the head of the brake release bolt passes through the second axial through hole of the movable piston, and the tail end passes through the fourth axial through hole of the annular sealing plate of the housing and extends to the outside of the housing, and the tail end of the brake release bolt is threadedly connected with a lock nut; the brake release bolt is used to manually release the brake when the vehicle has no oil pressure;

[0017] A third sealing ring is provided between the fourth axial through hole of the annular sealing plate and the brake release bolt; a fixing plate is provided between the annular sealing plate and the lock nut, and the fixing plate is fixedly connected to the housing;

[0018] An annular limiting groove is provided at the opening of the first axial through hole of the annular sealing plate, and an annular boss is provided on the driving shaft. The annular boss is installed in the annular limiting groove and is axially limited by the fixing plate.

[0019] The inner cavity of the housing is a cylindrical cavity as a whole, and the inner wall of the driving cavity of the housing has a tooth groove parallel to the driving shaft;

[0020] The intermediate baffle is sleeved on the drive shaft and is located at an end of the housing drive cavity away from the fixed piston. The outer peripheral wall of the intermediate baffle has uniformly distributed external teeth, which mesh with the tooth grooves of the housing drive cavity and can slide along the tooth grooves.

[0021] The pressure plate is sleeved on the drive shaft and is located inside the driving cavity of the housing, close to one end of the fixed piston;

[0022] The friction disc assembly is a detachable annular multi-layer plate structure as a whole. The friction disc assembly is sleeved on the drive shaft, and the friction disc assembly is located between the intermediate baffle and the pressure plate. The inner hole of the friction disc assembly has a spline groove, and the spline groove cooperates with the first spline of the drive shaft and is slidably connected.

[0023] The oil circuit includes a main oil circuit, a first oil circuit and a second oil circuit. One end of the main oil circuit is connected to the oil tank, and the other end is connected to the first oil circuit and the second oil circuit respectively. The other ends of the first oil circuit and the second oil circuit are respectively connected to the loading oil chamber of a brake; the pump and the electromagnetic reversing valve are both arranged on the main oil circuit.

[0024] The main oil circuit is also connected to an overflow branch, one end of the overflow branch is connected to the oil tank, and the other end is connected to the electromagnetic reversing valve. An electric proportional overflow valve is provided on the overflow branch, and the electric proportional overflow valve is connected to the vehicle ECU.

[0025] The pressure plate is a circular plate-shaped structure as a whole. The pressure plate is slidably connected to the driving cavity of the shell, and an annular cavity is provided between the inner hole of the pressure plate and the driving shaft.

[0026] A retaining ring is provided in the driving cavity of the housing, and the fixed piston is limited by the retaining ring; a first sealing ring is provided between the outer circular surface of the fixed piston and the cylindrical inner cavity of the housing, and a second sealing ring is provided between the inner diameter surface of the fixed piston and the movable piston.

[0027] The end surface of the annular sealing plate facing the movable piston is evenly distributed with a first spring groove, and the end surface of the movable piston facing the annular sealing plate is evenly distributed with a second spring groove, the second spring grooves correspond one-to-one to the first spring grooves, and the compression spring is installed between the corresponding first spring groove and second spring groove; a fourth sealing ring is provided between the movable piston and the piston cavity of the housing.

[0028] The shell is provided with an oil injection channel, a gas release channel and an oil release channel corresponding to the position of the oil loading cavity, the oil injection channel is connected with an oil tank through an oil path, the gas release channel is connected with a gas release bolt, and the oil release channel is connected with an oil release bolt.

[0029] The utility model has the following beneficial effects: the utility model discloses the hydraulic electromagnetic valve control of braking, can control the braking system according to different braking intention, satisfies various driving and parking brake demand, response speed is fast, safe and reliable, and can realize the brake pressure loss protection in the emergency or vehicle failure, protects the safety of vehicle and driver, and the safety performance is higher, is suitable for mountain and hilly region of large gradient use, the utility model satisfies the safety and reliability of tractor braking system, ensures the braking safety performance in the hilly mountainous area large gradient climbing operation and emergency, guarantees the safety of driver, and then improves the vehicle whole machine adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is the control principle diagram of a kind of pressure loss protection brake device of the utility model;

[0031] Figure 2 It is the control method diagram of a kind of pressure loss protection brake device of the utility model;

[0032] Figure 3 It is the structure front view of a kind of pressure loss protection brake device of the utility model;

[0033] Figure 4 It is the A-A view of a kind of pressure loss protection brake device of the utility model;

[0034] Figure 5 It is the B-B view of a kind of pressure loss protection brake device in the utility model;

[0035] In the drawing: 1-engine;2-oil tank;3-gearbox;3.1-input shaft;3.2-differential steering planetary assembly;3.3-outer shell;4-brake;4.1-intermediate baffle;4.2-friction disc assembly;4.3-pressing disc;4.4-clamp ring;4.5-first sealing ring;4.6-fixed piston;4.7-gas release bolt;4.8-fourth sealing ring;4.9-moving piston;4.10-compression spring;4.11-housing;4.12-oil release bolt;4.13-unbrake bolt;4.14-third sealing ring;4.15-lock nut;5-driving shaft;6.1-electromagnetic reversing valve;6.2-electric proportional relief valve;7-pump. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following will be further described in detail in combination with the drawings and examples. It should be understood that in the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more than two; the directions or position relations indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like are based on the directions or position relations shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular direction, be constructed and operated in a particular direction, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] As Figures 1-5 shown, the utility model provides a kind of pressure loss protection brake device, comprising: gearbox 3, brake 4, drive shaft 5 and oil tank 2, the gearbox 3 has two groups of differential steering planetary assemblies 3.2, and the input shaft 3.1 of gearbox 3 is connected with one drive shaft 5 respectively by two groups of differential steering planetary assemblies 3.2;The outer circle surface of one end of each drive shaft 5 connected with corresponding differential steering planetary assembly 3.2 is equipped with first spline, and each drive shaft 5 is connected with one brake 4 by first spline respectively;

[0038] The brake 4 includes:

[0039] Shell 4.11 is sleeved on drive shaft 5, and shell 4.11 has cylindrical inner cavity, and one end of shell 4.11 is connected with the shell 3.3 of gearbox 3, and the other end of shell 4.11 has annular sealing plate, and the middle part of annular sealing plate has first axial through hole, and the outer periphery of first axial through hole has fourth axial through hole;

[0040] Fixed piston 4.6, fixed piston 4.6 is annular structure as a whole, and fixed piston 4.6 is installed in the middle part of the inner cavity of shell 4.11, to divide the inner cavity of shell 4.11 into piston cavity and drive cavity, and drive cavity is located between piston cavity and shell 3.3;The inner wall of drive cavity of shell 4.11 has tooth slot parallel to drive shaft 5;

[0041] The movable piston 4.9 is a two-step shaft structure consisting of a first step shaft and a second step shaft. A third axial through hole is defined in the middle of the movable piston 4.9, penetrating the first and second step shafts. A second axial through hole is defined on the periphery of the third axial through hole. The third axial through hole of the movable piston 4.9 is sleeved on the drive shaft 5. The first step shaft is slidably connected to the inner hole of the fixed piston 4.6, and the second step shaft is slidably connected to the piston cavity of the housing 4.11. The free end of the first step shaft extends through the inner hole of the fixed piston 4.6 into the drive cavity of the housing 4.11. The space between the second step shaft and the fixed piston 4.6 serves as an oil loading chamber.

[0042] The compression spring 4.10 is evenly distributed between the movable piston 4.9 and the annular sealing plate of the housing 4.11. When the volume of the loading oil chamber is at an initial state, the compression spring 4.10 maximizes the distance between the movable piston 4.9 and the annular sealing plate.

[0043] Release the brake bolt 4.13. The head of the release brake bolt 4.13 passes through the second axial through hole of the movable piston 4.9, and the tail end passes through the fourth axial through hole of the annular sealing plate of the housing 4.11 and extends to the outside of the housing 4.11. The tail end of the release brake bolt 4.13 is threadedly connected to the lock nut 4.15;

[0044] An intermediate baffle 4.1 is sleeved on the drive shaft 5 and is located inside the drive chamber of the housing 4.11 at one end away from the fixed piston 4.6. The outer peripheral wall of the intermediate baffle 4.1 has uniformly distributed external teeth that mesh with the tooth grooves of the drive chamber of the housing 4.11 and can slide along the tooth grooves;

[0045] The pressure plate 4.3 is sleeved on the drive shaft 5 and is located inside the drive cavity of the housing 4.11, near one end of the fixed piston 4.6;

[0046] The friction disc assembly 4.2 is a detachable annular multi-layer plate structure. The friction disc assembly 4.2 is sleeved on the drive shaft 5 and located between the intermediate baffle 4.1 and the pressure plate 4.3. The inner bore of the friction disc assembly 4.2 has a spline groove, which engages with the first spline of the drive shaft 5. The friction disc assembly 4.2 is a mature existing technology. The specific structure of the friction disc assembly 4.2 can be referred to as a multi-plate wet brake, and will not be further elaborated here.

[0047] The loading oil chamber of each brake 4 is connected to the hydraulic oil tank 2 via an oil circuit. A pump 7 and an electromagnetic reversing valve 6.1 are provided on the oil circuit. The electromagnetic reversing valve 6.1 is connected to the vehicle ECU.

[0048] The oil circuit includes a main oil circuit, a first oil circuit and a second oil circuit. One end of the main oil circuit is connected to the oil tank 2, and the other end is connected to the first oil circuit and the second oil circuit respectively. The other ends of the first oil circuit and the second oil circuit are respectively connected to a loading oil chamber of a brake 4; the pump 7 and the electromagnetic reversing valve 6.1 are both arranged on the main oil circuit.

[0049] The main oil circuit is also connected to an overflow branch, one end of which is connected to the oil tank 2 and the other end is connected to the electromagnetic reversing valve 6.1. The overflow branch is provided with an electric proportional overflow valve 6.2, which is connected to the vehicle ECU.

[0050] The pressure plate 4.3 is a circular plate-shaped structure as a whole. The pressure plate 4.3 is slidably connected to the driving cavity of the housing 4.11, and an annular cavity is provided between the inner hole of the pressure plate 4.3 and the driving shaft 5.

[0051] In the above structure, the pump 7 is driven by the engine 1 ; the differential steering planetary assembly 3 . 2 is a prior art, and two sets of differential steering planetary assemblies 3 . 2 form a differential steering planetary device, which is built into the gearbox 3 .

[0052] A retaining ring 4.4 is provided in the driving cavity of the housing 4.11, and the fixed piston 4.6 is limited by the retaining ring 4.4; a first sealing ring 4.5 is provided between the outer circumferential surface of the fixed piston 4.6 and the cylindrical inner cavity of the housing 4.11, and a second sealing ring is provided between the inner diameter surface of the fixed piston 4.6 and the outer circumferential surface of the first step shaft of the movable piston 4.9.

[0053] The end surface of the annular sealing plate facing the movable piston 4.9 is uniformly provided with a first spring groove, and the end surface of the movable piston 4.9 facing the annular sealing plate is uniformly provided with a second spring groove, each of which corresponds to the first spring groove. The compression spring 4.10 is installed between the corresponding first and second spring grooves. A fourth sealing ring 4.8 is provided between the second stepped shaft of the movable piston 4.9 and the cylindrical inner cavity of the housing 4.11.

[0054] A third sealing ring 4.14 is provided between the fourth axial through hole of the annular sealing plate and the brake release bolt 4.13; a fixing plate is provided between the annular sealing plate and the anti-loosening nut 4.15, and the fixing plate is fixedly connected to the housing 4.11; an annular limiting groove is provided at the opening of the first axial through hole of the annular sealing plate, and an annular boss is provided on the drive shaft 5, and the annular boss is installed in the annular limiting groove and is axially limited by the fixing plate.

[0055] The housing 4.11 is provided with an oil filling channel, an air release channel and an oil drain channel connected to the loading oil chamber at a position corresponding to the loading oil chamber. The oil filling channel is connected to the oil tank 2 through an oil circuit, the air release channel is connected to a air release bolt 4.7, and the oil drain channel is connected to an oil drain bolt 4.12.

[0056] The control method comprises the following steps:

[0057] Step S1, after the vehicle is started, the input shaft 3.1 in the gearbox 3 is not working, the electromagnetic reversing valve 6.1 is de-energized (closed), the electric proportional overflow valve 6.2 is de-energized (fully opened), the brake 4 is in the initial state, at this time, the loading oil cavity between the second stepped shaft and the fixed piston 4.6 has no pressure, the elastic force of the compression spring 4.10 is pressed to the pressure plate 4.3 through the moving piston 4.9, the friction disc assembly 4.2 is closed and rubs with the intermediate baffle 4.1 to generate friction braking;

[0058] Step S2, when the vehicle is forward or backward, the electromagnetic reversing valve 6.1 is energized (opened), the electric proportional overflow valve 6.2 is energized (closed), the hydraulic oil enters the loading oil cavity between the second stepped shaft and the fixed piston 4.6 from the oil circuit, the hydraulic pressure overcomes the elastic force of the compression spring 4.10, the moving piston 4.9 is separated from the pressure plate 4.3, the friction disc assembly 4.2 is separated and away from the intermediate baffle 4.1, and the brake 4 is released from the friction braking;

[0059] Step S3, when the vehicle is straightly driven, the electromagnetic reversing valve 6.1 is de-energized (closed), the electric proportional overflow valve 6.2 is energized (closed), the hydraulic oil in the loading oil cavity between the second stepped shaft and the fixed piston 4.6 keeps the working pressure, and the brake 4 keeps the state of releasing the friction braking;

[0060] Step S4, when the vehicle needs to be slowly braked or point-braked during the whole driving process, the electromagnetic reversing valve 6.1 is energized (opened), after the electric proportional overflow valve 6.2 receives the electric signal (brake pedal), the electric proportional overflow valve 6.2 is de-energized (opened and the flow is increased in proportion), the hydraulic oil in the loading oil cavity between the second stepped shaft and the fixed piston 4.6 is reduced, the elastic force of the compression spring 4.10 overcomes the hydraulic pressure, the moving piston 4.9 is pressed to the pressure plate 4.3, the pressure plate 4.3 presses the friction disc assembly 4.2 to move to the intermediate baffle 4.1, the friction disc assembly 4.2 is slowly closed and rubs with the intermediate baffle 4.1 to generate friction braking, the friction disc assembly 4.2 drives the driving shaft 5 to stop rotating, and slow braking or point-braking is realized;

[0061] Step S5, when the vehicle is emergency-braked during the driving process, the electromagnetic reversing valve 6.1 is de-energized (closed), the electric proportional overflow valve 6.2 is de-energized (fully opened), under the action of the compression spring 4.10, the moving piston 4.9 is reset, the hydraulic oil in the loading oil cavity between the second stepped shaft and the fixed piston 4.6 enters the oil tank 2 through the oil circuit, the compression spring 4.10 drives the moving piston 4.9 to move, the friction disc assembly 4.2 and the intermediate baffle 4.1 of the brake 4 are pressed at the same time, at this time, the friction disc assembly 4.2 and the intermediate baffle 4.1 are tightly combined under the action of the elastic force of the compression spring 4.10, the driving shaft 5 is quickly stopped from rotating, and emergency braking of the vehicle is realized;

[0062] Step S6, when the vehicle emergency brake is released, first put the gear in neutral, then put the gear in forward or reverse, the electromagnetic reversing valve 6.1 is powered on (open), the electric proportional overflow valve 6.2 is powered on (closed), the hydraulic oil enters the loading oil chamber between the second stepped shaft and the fixed piston 4.6, the hydraulic pressure overcomes the elastic force of the compression spring 4.10, the moving piston 4.9 moves away from the pressure plate 4.3, the friction disc assembly 4.2 is separated and away from the intermediate baffle 4.1, and the brake 4 is released from the friction braking.

[0063] When the vehicle engine 1 is shut down due to hydraulic system failure, accidental power failure or vehicle whole machine stop working, the electromagnetic reversing valve 6.1 is powered off (closed), the electric proportional overflow valve 6.2 is powered off (fully open), the hydraulic oil in the loading oil chamber between the second stepped shaft and the fixed piston 4.6 returns to the tank 2 through the electric proportional overflow valve 6.2 under the action of the compression spring 4.10, the compression spring 4.10 pushes the moving piston 4.9 to move, the friction disc assembly 4.2 and the intermediate baffle 4.1 are pressed tightly, the drive shaft 5 stops working quickly, and the vehicle realizes automatic parking brake;

[0064] When the vehicle cannot be started and needs to be towed, the electromagnetic reversing valve 6.1 is powered on (open), the electric proportional overflow valve 6.2 is powered off (fully open), and the whole vehicle is in a braking state. At this time, the anti-loose nut 4.15 on the brake release bolt 4.13 needs to be tightened manually, the brake release bolt 4.13 drives the moving piston 4.9 to overcome the compression of the compression spring 4.10, so that the friction disc assembly 4.2 and the intermediate baffle 4.1 gradually separate, that is, the vehicle brake is released, and the transmission system is prevented from being damaged. Next time the vehicle works, the anti-loose nut 4.15 on the brake release bolt 4.13 needs to be completely loosened, so that the anti-loose nut 4.15 has a gap of 1-1.5 mm with the fixed plate.

[0065] The shaft end of the drive shaft 5 is provided with a second spline, and the drive shaft 5 is connected with the corresponding differential steering planetary assembly 3.2 through the second spline.

[0066] When installing the brake 4: first, connect the driving shaft 5 and the shell 4.11. Put the compression spring 4.10 into the first spring groove of the shell 4.11; after the fourth sealing ring 4.8 is put into the sealing groove of the moving piston 4.9, the compression spring 4.10 and the second spring groove of the moving piston 4.9 are matched one by one; the third sealing ring 4.14 is installed in the clamping groove of the release brake bolt 4.13, the release brake bolt 4.13 passes through the moving piston 4.9, the compression spring 4.10 and the shell 4.11 and is connected with the driving shaft 5, the lock nut 4.15 is tightened, the compression spring 4.10 is compressed; the first sealing ring 4.5 and the second sealing ring are put into the inner and outer sealing grooves of the fixed piston 4.6, then the fixed piston 4.6 is installed between the moving piston 4.9 and the shell 4.11 and is limited by the clasp 4.4; then the pressure plate 4.3, the friction disc assembly 4.2 and the intermediate baffle 4.1 are sequentially put in, the friction disc assembly 4.2 is matched with the first spline of the driving shaft 5; finally, the shaft end with the second spline of the driving shaft 5 is inserted into the differential steering planetary assembly 3.2 of the gearbox 3, the driving shaft 5 is connected with the gearbox 3, finally, the air release bolt 4.7 and the oil drain bolt 4.12 are installed.

[0067] The above only describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0068] The part not described in the present application is prior art.

Claims

1. A pressure loss protection braking device, comprising: A gearbox (3), a brake (4), a drive shaft (5) and an oil tank (2), characterized in that: the gearbox (3) has two sets of differential steering planetary assemblies (3.2); the input shaft (3.1) of the gearbox (3) is connected to a drive shaft (5) through the two sets of differential steering planetary assemblies (3.2); the outer surface of one end of each drive shaft (5) connected to the corresponding differential steering planetary assembly (3.2) is provided with a first spline, and each drive shaft (5) is connected to a brake (4) through the first spline; The brake (4) comprises a housing (4.11), a fixed piston (4.6), a movable piston (4.9), a compression spring (4.10), an intermediate baffle (4.1), a pressure plate (4.3), and a friction plate assembly (4.2); the housing (4.11) is sleeved on the drive shaft (5), one end of the housing (4.11) is connected to the outer shell (3.3) of the gearbox (3), and the other end of the housing (4.11) has an annular sealing plate, the middle of the annular sealing plate has a first axial through hole, and the periphery of the first axial through hole has a fourth axial through hole; The fixed piston (4.6) is an annular structure as a whole. The fixed piston (4.6) is installed in the middle of the inner cavity of the housing (4.11), dividing the inner cavity of the housing (4.11) into a piston cavity and a drive cavity. The drive cavity is located between the piston cavity and the outer shell (3.3); the intermediate baffle (4.1), the pressure plate (4.3) and the friction disc assembly (4.2) are all installed in the drive cavity. The friction disc assembly (4.2) is slidably connected to the first spline on the drive shaft (5); one end of the movable piston (4.9) is installed in the piston cavity, and the other end passes through the fixed piston (4.6) and extends into the drive cavity; a loading oil cavity is provided between the movable piston (4.9) and the fixed piston (4.6); The compression spring (4.10) is evenly distributed between the movable piston (4.9) and the annular sealing plate. The elastic force of the compression spring (4.10) sequentially presses the pressure plate (4.3) and the friction plate assembly (4.2) toward the intermediate baffle (4.1) through the movable piston (4.9), thereby pressing the friction plate assembly (4.2) and generating braking. The loading oil chamber of each brake (4) is connected to the hydraulic oil tank (2) via an oil circuit, wherein a pump (7) and an electromagnetic reversing valve (6.1) are provided on the oil circuit, and the electromagnetic reversing valve (6.1) is connected to the vehicle ECU; when oil is injected into the loading oil chamber, the oil pressure causes the movable piston (4.9) to move toward the annular sealing plate, thereby releasing the brake.

2. The pressure loss protection brake device according to claim 1, characterized in that: The movable piston (4.9) as a whole is a two-stage stepped shaft structure consisting of a first stepped shaft and a second stepped shaft, and a third axial through hole is provided in the middle of the movable piston (4.9) and passes through the first and second stepped shafts, and a second axial through hole is provided on the periphery of the third axial through hole; the third axial through hole of the movable piston (4.9) is sleeved on the drive shaft (5), the first stepped shaft is slidably connected to the inner hole of the fixed piston (4.6), and the second stepped shaft is slidably connected to the piston cavity of the housing (4.11); the free end of the first stepped shaft extends through the inner hole of the fixed piston (4.6) to the drive cavity of the housing (4.11); and the space between the second stepped shaft and the fixed piston (4.6) serves as a loading oil cavity.

3. The pressure loss protection brake device according to claim 2, characterized in that: A brake release bolt (4.13) is provided in the second axial through hole of the movable piston (4.9), the head of the brake release bolt (4.13) passes through the second axial through hole of the movable piston (4.9), and the tail end passes through the fourth axial through hole of the annular sealing plate of the housing (4.11) and extends to the outside of the housing (4.11), and the tail end of the brake release bolt (4.13) is threadedly connected to a lock nut (4.15); the brake release bolt (4.13) is used for manually releasing the brake when the vehicle is in a state of no oil pressure; A third sealing ring (4.14) is provided between the fourth axial through hole of the annular sealing plate and the brake release bolt (4.13); a fixing plate is provided between the annular sealing plate and the anti-loosening nut (4.15), and the fixing plate is fixedly connected to the housing (4.11); The first axial through hole opening of the annular sealing plate is provided with an annular limiting groove, and the driving shaft (5) is provided with an annular boss, which is installed in the annular limiting groove and is axially limited by the fixing plate.

4. The pressure loss protection brake device according to claim 1, characterized in that: The inner cavity of the housing (4.11) is a cylindrical cavity as a whole, and the inner wall of the driving cavity of the housing (4.11) has tooth grooves parallel to the driving shaft (5); The intermediate baffle (4.1) is sleeved on the drive shaft (5), and the intermediate baffle (4.1) is located at one end of the drive chamber of the housing (4.11) away from the fixed piston (4.6), and the outer peripheral wall of the intermediate baffle (4.1) has uniformly distributed external teeth, which are engaged with the tooth grooves of the drive chamber of the housing (4.11) and can slide along the tooth grooves; The pressure plate (4.3) is sleeved on the drive shaft (5), and the pressure plate (4.3) is located inside the drive cavity of the housing (4.11) and close to one end of the fixed piston (4.6); The friction disc assembly (4.2) is a detachable annular multi-layer plate structure as a whole. The friction disc assembly (4.2) is sleeved on the drive shaft (5), and the friction disc assembly (4.2) is located between the intermediate baffle (4.1) and the pressure plate (4.3). The inner hole of the friction disc assembly (4.2) has a spline groove, and the spline groove cooperates with the first spline of the drive shaft (5) and is slidably connected.

5. The pressure loss protection brake device according to claim 1, characterized in that: The oil circuit comprises a main oil circuit, a first oil circuit, and a second oil circuit; one end of the main oil circuit is connected to the oil tank (2), and the other end is connected to the first oil circuit and the second oil circuit respectively; the other ends of the first oil circuit and the second oil circuit are respectively connected to a loading oil chamber of a brake (4); the pump (7) and the electromagnetic reversing valve (6.1) are both arranged on the main oil circuit.

6. The pressure loss protection brake device according to claim 5, characterized in that: The main oil circuit is also connected to an overflow branch, one end of the overflow branch is connected to the oil tank (2), and the other end is connected to the electromagnetic reversing valve (6.1). An electric proportional overflow valve (6.2) is provided on the overflow branch, and the electric proportional overflow valve (6.2) is connected to the vehicle ECU.

7. The pressure loss protection brake device according to claim 1, characterized in that: The pressure plate (4.3) is an annular plate-shaped structure as a whole. The pressure plate (4.3) is slidably connected to the drive cavity of the housing (4.11), and an annular cavity is provided between the inner hole of the pressure plate (4.3) and the drive shaft (5).

8. The pressure loss protection brake device according to claim 1, characterized in that: A snap ring (4.4) is provided in the driving cavity of the housing (4.11), and the fixed piston (4.6) is limited by the snap ring (4.4); a first sealing ring (4.5) is provided between the outer cylindrical surface of the fixed piston (4.6) and the cylindrical inner cavity of the housing (4.11), and a second sealing ring is provided between the inner diameter surface of the fixed piston (4.6) and the movable piston (4.9).

9. The pressure loss protection brake device according to claim 1, characterized in that: The end surface of the annular sealing plate facing the movable piston (4.9) is uniformly provided with first spring grooves, and the end surface of the movable piston (4.9) facing the annular sealing plate is uniformly provided with second spring grooves, the second spring grooves corresponding to the first spring grooves one by one, and the compression spring (4.10) is installed between the corresponding first spring grooves and second spring grooves; a fourth sealing ring (4.8) is provided between the movable piston (4.9) and the piston cavity of the housing (4.11).

10. The pressure loss protection brake device according to claim 1, characterized in that: The housing (4.11) is provided with an oil filling channel, an air release channel, and an oil drain channel connected to the loading oil chamber at a position corresponding to the loading oil chamber. The oil filling channel is connected to the oil tank (2) via an oil circuit, the air release channel is connected to an air release bolt (4.7), and the oil drain channel is connected to an oil drain bolt (4.12).

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