Electric drive assembly and engineering machinery

Abstract

The invention discloses an electric drive assembly and engineering machinery. The electric drive assembly comprises a drive motor assembly and a final transmission assembly. The parking brake is arranged at the first end of a rotating shaft of the driving motor, and the driving motor can achieve dynamic braking during driving. The final transmission assembly comprises a first-stage planet row, a second-stage planet row, a third-stage planet row and a service brake. The second end of a rotating shaft of the driving motor is in transmission connection with a first-stage sun gear of a first-stage planet row and then sequentially drives a second-stage planet row and a third-stage planet row, power is output by a third-stage planet carrier of the third-stage planet row, the third-stage planet carrier is connected with a chain wheel, and the chain wheel is connected with a hub body; a service brake is arranged on the hub body and is used for generating or releasing service braking on the hub body; the service brake is externally connected with a cooling circulation oil way, a friction plate is forcibly cooled, and safety and reliability are improved. The caliper disc type parking brake is placed outside the driving motor, the braking torque is amplified through the three-level large reduction ratio, and the requirement for the braking torque of the caliper disc type parking brake is lowered.

Description

Technical Field

[0001] This application belongs to the technical field of mechanical transmission and relates to an electric drive assembly and construction machinery. Background Art

[0002] Currently, construction machinery products (such as bulldozers) are developing towards electric drive assemblies, and it is necessary to add drive motors under the limited space layout of the bulldozer frame. The high-speed motor input requires a large reduction ratio for the final drive, and the planetary reduction structure with three or more stages further increases the volume space of the final drive, bringing challenges to the axial connection space between the drive motor and the final drive of the bulldozer. At the same time, in order to meet the requirements of the electric drive bulldozer for driving and parking on slopes, the drive motor of a general bulldozer has dynamic braking, which is often used as the service brake, and a normally closed braking structure is designed in the final drive as the parking brake. When the total mass of the bulldozer is greater than 100 tons, a single drive motor dynamic braking requires a significant increase in its volume space to arrange high-power braking resistors and cooling and lubrication pipelines, and it is easy to cause the braking resistor of the motor to overload and fail during long-term braking, and it can no longer meet the safe and reliable service braking of the bulldozer on large slopes. In addition, in order to improve its operation efficiency, the continuous increase in the total mass and power of the bulldozer makes the required value of the braking torque of its parking brake also continuously increase. When a normally closed parking wet brake is integrally designed at the input end of the final drive, problems such as heat generation of the friction plate during driving and high temperature of the transmission system often occur, and its safety and reliability are difficult to guarantee. In working scenarios such as open-pit coal mines and mines, the operating conditions of bulldozers are harsh, with large loads and large parking slopes, which put higher requirements on the power performance, braking performance, lubrication, and reliability of their electric drive assemblies. Especially when going down long slopes, a large amount of heat will be generated during service braking, and efficient cooling design of the brake has also become the key to the design.

[0003] Therefore, in order to adapt to different vehicle total masses, especially the strict requirements of large-tonnage and large-horsepower electric drive crawler bulldozers for power performance and braking performance, it is of great practical significance to newly design an electric drive assembly with highly reliable service braking and parking braking. Summary of the Invention

[0004] Objective: In view of at least one of the above technical problems, this application provides an electric drive assembly and construction machinery.

[0005] Technical Solution: To solve the above technical problems, the technical solution adopted in this application is as follows: In the first aspect, an electric drive assembly is provided, including a drive motor assembly and a final drive assembly; The drive motor assembly includes a drive motor and a parking brake. The parking brake is arranged at the first end of the drive motor rotating shaft and is used to generate or release the parking brake for the drive motor, and the drive motor can achieve service dynamic braking; The final drive assembly includes a first-stage planetary gear set, a second-stage planetary gear set, a third-stage planetary gear set, and a service brake; The first-stage planetary gear set includes a first-stage ring gear, a first-stage sun gear, first-stage planet gears, a first-stage planet carrier, and a transmission shaft; the first-stage sun gear is drivingly connected to the second end of the driving motor shaft and meshes with the first-stage planet gears, the first-stage planet gears are axially positioned on the first-stage planet carrier and drivingly connected to the first-stage planet carrier, the first-stage planet carrier is drivingly connected to the transmission shaft, the first-stage ring gear meshes with the first-stage planet gears and the first-stage ring gear is fixed, and power is output through the first-stage planet carrier; The second-stage planetary gear set includes a second-stage sun gear, a second-stage planet carrier, second-stage planet gears, and a second- and third-stage ring gear, the second-stage sun gear is drivingly connected to the transmission shaft and meshes with the second-stage planet gears, the second-stage planet gears are axially positioned on the second-stage planet carrier and drivingly connected to the second-stage planet carrier, the second- and third-stage ring gear meshes with the second-stage planet gears and the second- and third-stage ring gear is fixed, and power is output through the second-stage planet carrier; The third-stage planetary gear set includes a third-stage sun gear, third-stage planet gears, a third-stage planet carrier, a sprocket, and a hub; the second- and third-stage ring gear meshes with the third-stage planet gears, the third-stage sun gear is drivingly connected to the second-stage planet carrier and meshes with the third-stage planet gears; the third-stage planet gears are axially positioned on the third-stage planet carrier and drivingly connected to the third-stage planet carrier, the third-stage planet carrier is connected to the sprocket, and the sprocket is connected to the hub; A service brake is arranged on the hub for applying or releasing service braking to the hub; the service brake is externally connected to a cooling circulation oil circuit for dissipating heat and cooling the service brake.

[0006] In some embodiments, the electric drive assembly further includes a support shaft connected to the vehicle frame, and the first-stage ring gear and the second- and third-stage ring gear are both directly or indirectly fixed on the support shaft.

[0007] Further, in some embodiments, the driving motor housing is connected to the support shaft; the first housing of the service brake is connected to the support shaft.

[0008] Further, in some embodiments, the driving motor is a permanent magnet synchronous motor equipped with a braking resistor of a certain power, which can consume the back electromotive force generated during the braking process of the driving motor to achieve dynamic service braking.

[0009] Further, in some embodiments, the parking brake adopts a disc type parking brake, including a brake disc, a brake, a spline sleeve, and an end cover; the first end of the driving motor shaft is drivingly connected to the spline sleeve, and the spline sleeve is axially limited by the end cover, the brake disc is connected to the spline sleeve, one or more brakes are arranged on the brake disc, and the brakes are connected to the driving motor housing.

[0010] Further, in some embodiments, the brake is a normally closed high-pressure brake, which contains multiple groups of compression-deformed disc springs for squeezing the friction plates of the brake, so that the friction plates contact the brake disc to generate a braking torque and prevent the rotation of the driving motor shaft.

[0011] In some embodiments, the service brake includes a first housing, a second housing, a piston, a driving friction plate, a driven friction plate, a spring and a guide bolt; The first housing and the second housing are detachably and sealingly connected to form a service brake housing. The driving friction plate is splined to the outer ring of the hub, and the driven friction plate is splined to the inner wall of the second housing. The driven friction plate and the driving friction plate are arranged in a crosswise and side-by-side contact manner. The piston is movably and sealingly installed in the second housing. The springs are circumferentially distributed in the piston and fixed to the second housing through the guide bolts. The springs are sleeved on the guide bolts, with one end limitedly installed at the nut end of the guide bolt and the other end limitedly installed at one end of the piston close to the second housing.

[0012] Further, in some embodiments, a pressure oil port is provided on the second housing, and a hydraulic cavity is jointly formed among the second housing, the piston and the pressure oil port; when the service brake works, the piston is pushed by the hydraulic oil entering the hydraulic cavity from the pressure oil port to squeeze the driving friction plate and the driven friction plate to generate a frictional torque, preventing the rotation of the hub and generating a service brake; when the service brake does not work, the piston retracts under the action of the spring and disengages from the driving friction plate and the driven friction plate, thereby releasing the service brake.

[0013] Further, in some embodiments, a floating oil seal is installed between the first housing and the hub to isolate it from the external environment and isolate it from the internal oil cavity of the final drive assembly through the floating oil seal.

[0014] Further, in some embodiments, the service brake further includes a cooling oil inlet, a cooling oil outlet provided on the second housing, and a housing oil passage connecting the cooling oil inlet and the cooling oil outlet. The housing oil passage is connected to the driving friction plate and the driven friction plate. The cooling oil outlet is connected to the oil inlet of the radiator, and the oil outlet of the radiator is connected to the cooling oil inlet to form a cooling circulation oil circuit.

[0015] Further, there are two cooling oil inlets and two cooling oil outlets respectively, which are symmetrically distributed on the second housing; there are two pressure oil ports, which are symmetrically arranged on the second housing.

[0016] In a second aspect, a construction machine is provided, including the electric drive assembly described above.

[0017] In some embodiments, the construction machine further includes a crawler wheel, and the sprocket is meshed and drivingly connected with the crawler wheel.

[0018] Beneficial effects: The electric drive assembly and engineering machinery provided by the present application, under the trend of large-scale and electrified development of engineering machinery, in order to meet the requirements of the braking torque, braking safety and reliability of the whole vehicle after the bulldozer continues to increase its own weight, avoid the braking risk caused by the failure of the dynamic brake of a single motor, and solve the problems of serious heating of the friction plate belt row of the brake at the input end of the existing electric drive bulldozer and difficulty in heat dissipation. The present application provides a high-reliability electric drive assembly for a crawler bulldozer, which adopts a transmission route of parking brake + drive motor input → first-stage planetary gear → transmission shaft → second-stage planetary gear → third-stage planetary gear → driving brake + sprocket output. Among them, the motor directly drives the final drive, and the driving motor is used to realize the driving dynamic braking. At the same time, the parking caliper disc brake is placed outside the driving motor, and the braking torque is amplified by the three-stage large reduction ratio of the final drive, thereby reducing the braking torque requirements of the caliper disc brake itself, facilitating the selection of brakes and the upgrading of braking performance, and avoiding the risk of the vehicle being unable to stop after the failure of the single driving brake of the vehicle. The final drive is composed of a three-stage planetary gear. A mechanical hydraulic service brake is added at the output end of the final drive. There is sufficient space between the sprocket of the final drive and the frame. By increasing the number of friction plate groups, the increasing demand for vehicle braking torque can be met. In addition, the service brake is connected to an external cooling oil circuit and uses forced heat dissipation cooling. The friction plate will not sinter at high temperature, ensuring the safety and reliability of braking in long downhill conditions. It has the following advantages: 1) The driving and parking brakes are modularly designed. The parking brake can achieve the required braking torque by selecting brake discs of different diameters and arranging one or more brakes. The driving brake can achieve the required braking torque by increasing or decreasing the number of friction plate groups and adjusting the brake oil pressure. This can meet the needs of upgrading the braking performance of electric bulldozers or developing models with a larger vehicle mass (more than 100 tons); 2) The drive motor has a dynamic braking function, which cooperates with the wet friction plate service brake of the final drive to avoid the braking risk caused by the failure of a single service brake function, making the entire electric drive service brake safer and more reliable; 3) The service brake is placed at the rear end of the sprocket, the speed difference between the driving and driven friction plates is small, the friction plate belt generates less heat, and the risk of high-temperature sintering of the friction plate is avoided. The forced heat dissipation design of the service brake ensures that the heat of the friction plate is taken away by the cooling oil in time during service braking, and the safety and reliability are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a cross-sectional schematic diagram of an electric drive assembly according to an embodiment of the present application; Figure 2 This is a connection diagram of an electric drive assembly according to an embodiment of the present application; Figure 3 It is a structural schematic diagram of a driving motor assembly according to an embodiment of the present application; Figure 4Schematic structural diagram of a service brake according to an embodiment of the present application; Figure 5 Schematic diagram of the external oil port arrangement of a service brake according to an embodiment of the present application; Figure 6 Schematic diagram of the internal oil circuit arrangement of a service brake according to an embodiment of the present application; Figure 7 Schematic diagram of the layout of the electric drive assembly of a crawler bulldozer according to an embodiment of the present application; In the figure: drive motor assembly 1, drive motor 1-1, parking brake, brake 1-3, brake disc 1-2, spline sleeve 1-4, end cover 1-5, parking brake pressure oil port 1-6, first bolt 6, second bolt 7, third bolt 8, fourth bolt 9, fifth bolt 10, sixth bolt 11, seventh bolt 12, eighth bolt 13, frame 14, crawler assembly 15; first-stage planetary gear set 2, second-stage planetary gear set 3, third-stage planetary gear set 4, service brake 5; support shaft 2-1, first-stage ring gear 2-2, first-stage sun gear 2-3, first-stage planetary gear 2-4, first-stage planetary carrier 2-5, transmission shaft 2-6, first-stage planetary pin 2-7, wear-resistant pad 2-8; second-stage sun gear 3-1, second-stage planetary gear 3-2, second- and third-stage ring gear 3-3, second-stage planetary carrier 3-4, ring gear support 3-5, second-stage planetary pin 3-6, planetary pin pressing plate 3-7; third-stage sun gear 4-1, third-stage planetary gear 4-2, third-stage planetary carrier 4-3, third-stage planetary pin 4-4, sprocket 4-5, hub body 4-6; service brake 5, first housing 5-1, second housing 5-2, piston 5-3, active friction plate 5-4, driven friction plate 5-5, first sealing ring 5-6, second sealing ring 5-7, spring 5-8, guide bolt 5-9, third sealing ring 5-10, floating oil seal 5-11, pressure oil port 521, cooling oil inlet 522, cooling oil outlet 523, housing oil passage 524. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes a limitation to the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0021] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of this application. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0022] In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of this application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0023] In the description of this application, it should be noted that, unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood through specific circumstances.

[0024] Embodiment 1: As Figures 1 to 6 shown, an electric drive assembly includes a drive motor assembly 1 and a final drive assembly; As Figure 1As shown, the drive motor assembly 1 includes a drive motor 1-1 and a parking brake. The parking brake is arranged at the first end of the rotating shaft of the drive motor 1-1 and is used to generate or release the parking brake on the drive motor, and the drive motor 1-1 can achieve dynamic braking during driving; As Figure 1 shown, the final drive assembly includes a first-stage planetary gear set 2, a second-stage planetary gear set 3, a third-stage planetary gear set 4, and a service brake 5; The first-stage planetary gear set 2 includes a first-stage ring gear 2-2, a first-stage sun gear 2-3, first-stage planetary gears 2-4, a first-stage planet carrier 2-5, and a transmission shaft 2-6. The first-stage sun gear 2-3 is drivingly connected to the second end of the rotating shaft of the drive motor 1-1 and meshes with the first-stage planetary gears 2-4. The first-stage planetary gears 2-4 are axially positioned and mounted on the first-stage planet carrier 2-5 and drivingly connected to the first-stage planet carrier 2-5. The first-stage planet carrier 2-5 is drivingly connected to the transmission shaft 2-6. The first-stage ring gear 2-2 meshes with the first-stage planetary gears 2-4 and the first-stage ring gear 2-2 is fixed. Power is output through the first-stage planet carrier 2-5; The second-stage planetary gear set 3 includes a second-stage sun gear 3-1, a second-stage planet carrier 3-4, second-stage planetary gears 3-2, and a second- and third-stage ring gear 3-3. The second-stage sun gear 3-1 is drivingly connected to the transmission shaft 2-6 and meshes with the second-stage planetary gears 3-2. The second-stage planetary gears 3-2 are axially positioned and mounted on the second-stage planet carrier 3-4 and drivingly connected to the second-stage planet carrier 3-4. The second- and third-stage ring gear 3-3 meshes with the second-stage planetary gears 3-2 and the second- and third-stage ring gear 3-3 is fixed. Power is output through the second-stage planet carrier 3-4; The third-stage planetary gear set 4 includes a third-stage sun gear 4-1, third-stage planetary gears 4-2, a third-stage planet carrier 4-3, a sprocket 4-5, and a hub 4-6. The second- and third-stage ring gear 3-3 meshes with the third-stage planetary gears 4-2. The third-stage sun gear 4-1 is drivingly connected to the second-stage planet carrier 3-4 and meshes with the third-stage planetary gears 4-2. The third-stage planetary gears 4-2 are axially positioned and mounted on the third-stage planet carrier 4-3 and drivingly connected to the third-stage planet carrier 4-3. The third-stage planet carrier 4-3 is connected to the sprocket 4-5, and the sprocket 4-5 is connected to the hub 4-6; A service brake 5 is arranged on the hub 4-6 and is used to generate or release the service brake on the hub 4-6. The service brake 5 is externally connected to a cooling circulation oil circuit and is used to dissipate heat and cool the service brake 5.

[0025] In some embodiments, as Figure 1As shown in the figure, the electric drive assembly further includes a support shaft 2-1 connected to the vehicle frame 14. The first-stage gear ring 2-2 and the second- and third-stage gear rings 3-3 are both fixed on the support shaft 2-1. The drive motor housing is connected to the support shaft 2-1. In this embodiment, the first-stage gear ring 2-2 of the first-stage planetary gear set is fixed on the support shaft 2-1 by the fourth bolt 9, the drive motor housing is fixed on the support shaft 2-1 by the third bolt 8, and the first housing 5-1 of the service brake 5 is also fixed on the support shaft 2-1 by the sixth bolt 11. The first housing 5-1 and the second housing 5-2 are connected by the seventh bolt 12. The support shaft 2-1, as the main load-bearing component of the electric drive assembly, is finally connected to the vehicle frame 14 of the construction machinery by the fifth bolt 10.

[0026] In this embodiment, the drive motor 1-1 is a permanent magnet synchronous motor, equipped with a braking resistor with a certain power, which can consume the back electromotive force generated during the braking process of the drive motor and achieve dynamic vehicle braking, and to a certain extent, perform the function of vehicle service braking.

[0027] In this embodiment, as Figures 1 to 3 shown in the figure, the parking brake adopts a caliper disc parking brake, including a brake disc 1-2, a brake 1-3, a spline sleeve 1-4, and an end cover 1-5. The external spline at the first end of the rotating shaft of the drive motor 1-1 is in mating connection with the internal spline of the spline sleeve 1-4, and the spline sleeve 1-4 is axially limited by the end cover 1-5 to prevent its axial movement. The brake disc 1-2 is fixedly connected to the spline sleeve 1-4 by the second bolt 7. One or more brakes 1-3 are arranged on the brake disc 1-2, and the brakes 1-3 are fixed on the drive motor housing by the first bolt 6.

[0028] Furthermore, the brake 1-3 is a normally closed high-pressure brake, which contains multiple groups of compression-deformed disc springs for squeezing the friction plates of the brake, so that the friction plates contact the brake disc to generate a braking torque and prevent the rotating shaft of the drive motor from rotating. By arranging the caliper disc parking brake on the drive motor and selecting a brake disc 1-2 with a suitable diameter size and arranging one or more brakes 1-3 on the brake disc, the actual requirements of different braking torque magnitudes can be conveniently achieved. As Figure 3 shown in the figure, when the vehicle is in motion, high-pressure oil passes through the parking brake pressure oil port 1-6 to restore the compression-deformed disc springs in the brake 1-3, and the friction plates are disengaged from the brake disc, and the rotating shaft of the drive motor 1-1 rotates normally.

[0029] In this embodiment, the first-stage planetary gear set 2 includes a support shaft 2-1 connected to the drive motor and the vehicle frame 14, a first-stage ring gear 2-2 connected to the support shaft 2-1, a first-stage sun gear 2-3 splined to the second end of the drive motor rotating shaft, first-stage planetary gears 2-4, a first-stage planetary carrier 2-5, a transmission shaft 2-6, first-stage planetary pin shafts 2-7, and wear-resistant pads 2-8. The first-stage planetary carrier 2-5 has an internal spline, and the internal spline is connected to the transmission shaft 2-6. The first-stage sun gear 2-3 is splined and connected to the output end of the drive motor 1-1 through an internal spline and meshes with the first-stage planetary gears 2-4. The first-stage planetary gears 2-4 are positioned by the first-stage planetary pin shafts 2-7 and the first-stage planetary carrier 2-5. The wear-resistant pads 2-8 are used to prevent the axial movement of the first-stage planetary carrier 2-5.

[0030] The second-stage planetary gear set 3 includes a second-stage sun gear 3-1, second-stage planetary gears 3-2, a second- and third-stage ring gear 3-3, a second-stage planetary carrier 3-4, a ring gear support 3-5, second-stage planetary pin shafts 3-6, and planetary pin shaft pressing plates 3-7. The ring gear support 3-5 is used to support and fix the second- and third-stage ring gear 3-3 on the support shaft 2-1. The second-stage sun gear 3-1 serves as a power input component, is connected to the transmission shaft 2-6 through an internal spline, and meshes with the second-stage planetary gears 3-2. The second-stage planetary gears 3-2 are positioned by the second-stage planetary pin shafts 3-6 and the second-stage planetary carrier 3-4. The planetary pin shaft pressing plates 3-7 fix the second-stage planetary pin shafts 3-6 on the second-stage planetary carrier 3-4 to prevent the axial movement of the second-stage planetary pin shafts 3-6, and the power is output through the second-stage planetary carrier 3-4.

[0031] The third-stage planetary gear set 4 includes a third-stage sun gear 4-1, third-stage planetary gears 4-2, a third-stage planetary carrier 4-3, third-stage planetary pin shafts 4-4, a sprocket 4-5, and a hub body 4-6. The third-stage sun gear 4-1 is connected to the second-stage planetary carrier 3-4 through an external spline and meshes with the third-stage planetary gears 4-2. The third-stage planetary gears 4-2 are positioned by the third-stage planetary pin shafts 4-4 and the third-stage planetary carrier 4-3. The planetary pin shaft pressing plates 3-7 and bolts fix the third-stage planetary pin shafts 4-4 on the third-stage planetary carrier 4-3 to prevent the axial movement of the third-stage planetary pin shafts 4-4. The third-stage planetary carrier 4-3 is connected to the sprocket 4-5 through bolts. In addition, for the convenience of manufacturing, the sprocket 4-5 and the hub body 4-6 are designed separately, and the two are connected by an eighth bolt 13.

[0032] In some embodiments, such as Figure 4 、 Figure 5 、 Figure 6As shown in the figure, the service brake 5 includes a first housing 5-1, a second housing 5-2, a piston 5-3, a driving friction plate 5-4, a driven friction plate 5-5, a first sealing ring 5-6, a second sealing ring 5-7, a spring 5-8, a guide bolt 5-9, a third sealing ring 5-10 and a floating oil seal 5-11. The first housing 5-1 and the second housing 5-2 are detachably and sealingly connected to form a service brake housing. Specifically, the first housing 5-1 and the second housing 5-2 are sealed by the third sealing ring 5-10 and connected together by the seventh bolt 12. The driving friction plate 5-4 is connected to the outer spline of the hub 4-6 through an internal spline. The driven friction plate 5-5 is arranged in a crosswise and side-by-side contact with the driving friction plate 5-4. The driven friction plate 5-5 is connected to the second housing 5-2 through an external spline. The piston 5-3 is movably and sealingly installed in the second housing 5-2 through the first sealing ring 5-6 and the second sealing ring 5-7. Specifically, the first sealing ring 5-6 and the second sealing ring 5-7 are respectively installed in the sealing ring grooves of the piston 5-3. The spring 5-8 is circumferentially distributed in the bolt holes of the piston 5-3 and fixed to the second housing 5-2 through the guide bolt 5-9. Specifically, the left end of the spring 5-8 is limitedly installed on the nut of the guide bolt 5-9, and the right end of the spring 5-8 is limitedly installed on the right end of the piston 5-3.

[0033] The second housing 5-2, the piston 5-3, the first sealing ring 5-6, the second sealing ring 5-7 and the pressure oil port 521 together form a hydraulic cavity. The pressure oil port 521 on the second housing 5-2 is communicated with the hydraulic cavity. When the service brake 5 works, under the action of high-pressure oil, the piston is pushed to squeeze the driving friction plate 5-4 and the driven friction plate 5-5 to generate a frictional torque, preventing the hub 4-6 from rotating and generating a service brake. When the service brake 5 does not work, the piston 5-3 returns under the action of the spring 5-8 and disengages from the driving friction plate 5-4 and the driven friction plate 5-5, thus releasing the service brake.

[0034] In this embodiment, as Figure 4 , Figure 5 , Figure 6 shown, the service brake 5 is forced lubricated and cooled. A floating oil seal 5-11 is installed between the first housing 5-1 and the hub 4-6 to isolate from the external environment and is isolated from the internal oil cavity of the final drive assembly through the floating oil seal. In some embodiments, the service brake 5 further includes a cooling oil inlet 522, a cooling oil outlet 523, and a housing oil passage 524 that connects the cooling oil inlet with the cooling oil outlet, the housing oil passage is connected to the active friction plate 5-4 and the driven friction plate 5-5, the cooling oil outlet is connected to the oil inlet of the radiator, and the oil outlet of the radiator is connected to the cooling oil inlet, forming a cooling circulation oil circuit. The cooling oil enters the active friction plate 5-4 and the driven friction plate 5-5 from the cooling oil inlet 522 and the housing oil passage 524, and the high-temperature hot oil generated during the braking process flows out from the cooling oil outlet 523 and is connected to the radiator of the vehicle. After the oil temperature is reduced by the radiator, the cooling oil flows back to the cooling oil inlet of the service brake 5, forming a cooling circulation oil circuit, so as to avoid the friction plate burning caused by excessively high driving brake temperature under long downhill conditions of large bulldozers, improve braking reliability, and extend service life.

[0035] In this embodiment, Figure 5 As shown, there are two cooling oil inlets 522 and two cooling oil outlets 523, which are symmetrically distributed on the second housing 5-2 so as to be common to both sides of the final drive.

[0036] In this embodiment, Figure 5 As shown, there are two pressure oil ports 521, which are symmetrically arranged on the second housing 5-2 so as to be commonly used on both sides of the final drive.

[0037] The transmission route of the drive axle of the present application is: parking brake + drive motor input → primary planetary gear 2 → transmission shaft 2-6 → secondary planetary gear 3 → tertiary planetary gear 4 → service brake 5 + sprocket 4-5 output. The drive motor integrates the caliper disc parking brake and motor dynamic braking functions. The primary, secondary and tertiary planetary gears in the final drive are all sun gear input, ring gear fixed, planet carrier output, and the service brake is integrated at the output end.

[0038] Embodiment 2: A construction machinery, comprising the electric drive assembly for construction machinery described in Embodiment 1.

[0039] Furthermore, if Figure 7 As shown, the engineering machinery further comprises a track assembly 15, the track assembly 15 comprises track wheels, and the sprockets 4-5 are meshingly transmission-connected with the track wheels.

[0040] In some embodiments, the engineering machine may be a bulldozer.

[0041] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An electric drive assembly, characterized in that, It includes a drive motor assembly and a final drive assembly; The drive motor assembly includes a drive motor and a parking brake. The parking brake is arranged at the first end of the drive motor rotating shaft and is used to generate or release the parking brake for the drive motor, and the drive motor can achieve dynamic braking during driving; The final drive assembly includes a first-stage planetary gear set, a second-stage planetary gear set, a third-stage planetary gear set and a service brake; The first-stage planetary gear set includes a first-stage ring gear, a first-stage sun gear, first-stage planetary gears, a first-stage planet carrier and a transmission shaft; the first-stage sun gear is in transmission connection with the second end of the drive motor rotating shaft and meshes with the first-stage planetary gears. The first-stage planetary gears are axially positioned and installed on the first-stage planet carrier and are in transmission connection with the first-stage planet carrier. The first-stage planet carrier is in transmission connection with the transmission shaft. The first-stage ring gear meshes with the first-stage planetary gears and the first-stage ring gear is fixed. The power is output through the first-stage planet carrier; The second-stage planetary gear set includes a second-stage sun gear, a second-stage planet carrier, second-stage planetary gears and a second- and third-stage ring gear. The second-stage sun gear is in transmission connection with the transmission shaft and meshes with the second-stage planetary gears. The second-stage planetary gears are axially positioned and installed on the second-stage planet carrier and are in transmission connection with the second-stage planet carrier. The second- and third-stage ring gear meshes with the second-stage planetary gears and the second- and third-stage ring gear is fixed. The power is output through the second-stage planet carrier; The third-stage planetary gear set includes a third-stage sun gear, third-stage planetary gears, a third-stage planet carrier, a sprocket and a hub. The second- and third-stage ring gear meshes with the third-stage planetary gears. The third-stage sun gear is in transmission connection with the second-stage planet carrier and meshes with the third-stage planetary gears. The third-stage planetary gears are axially positioned and installed on the third-stage planet carrier and are in transmission connection with the third-stage planet carrier. The third-stage planet carrier is connected to the sprocket, and the sprocket is connected to the hub; A service brake is arranged on the hub and is used to generate or release the service brake for the hub; the service brake is externally connected to a cooling circulation oil circuit and is used to dissipate heat and cool the service brake.

2. The electric drive assembly according to claim 1, wherein It also includes a support shaft connected to the vehicle frame. The first-stage ring gear and the second- and third-stage ring gear are both directly or indirectly fixed on the support shaft.

3. The electric drive assembly according to claim 2, characterized in that, The drive motor housing is connected to the support shaft; And / or, the first housing of the service brake is connected to the support shaft.

4. The electric drive assembly according to claim 1, characterized in that The drive motor is a permanent magnet synchronous motor and is equipped with a braking resistor with a certain power, which can consume the back electromotive force generated during the braking process of the drive motor to achieve dynamic braking during driving.

5. The electric drive assembly according to claim 1, wherein The parking brake adopts a caliper disc parking brake and includes a brake disc, a brake, a spline sleeve and an end cover; the first end of the drive motor rotating shaft is in transmission connection with the spline sleeve, and the spline sleeve is axially limited by the end cover. The brake disc is connected to the spline sleeve, and one or more brakes are arranged on the brake disc. The brakes are connected to the drive motor housing.

6. The electric drive assembly according to claim 1 or 5, characterized in that, The brake is a normally closed brake under high pressure and contains multiple groups of compression-deformed disc springs, which are used to squeeze the friction plates of the brake to make the friction plates contact the brake disc to generate a braking torque and prevent the drive motor rotating shaft from rotating.

7. The electric drive assembly according to claim 1, characterized in that, The service brake includes a first housing, a second housing, a piston, a driving friction plate, a driven friction plate, a spring and a guide bolt; The first shell and the second shell are detachably sealed and connected to form a service brake shell. The active friction plate is spline-connected to the outer ring of the hub, and the driven friction plate is spline-connected to the inner wall of the second shell. The driven friction plate and the active friction plate are arranged in cross-parallel contact. The piston movable seal is installed in the second shell. The spring is evenly distributed in the piston and is fixed to the second shell by a guide bolt. The spring is sleeved on the guide bolt, and one end is limitedly installed on the guide bolt nut end, and the other end is limitedly installed on the end of the piston close to the second shell.

8. The electric drive assembly according to claim 7, characterized in that, A pressure oil port is provided on the second housing, and a hydraulic cavity is formed between the second housing, the piston and the pressure oil port; when the service brake is working, the hydraulic oil entering the hydraulic cavity from the pressure oil port pushes the piston to squeeze the active friction plate and the driven friction plate to generate a friction torque, thereby preventing the hub body from rotating and generating service braking; when the service brake is not working, the piston retreats under the action of the spring and disengages from the active friction plate and the driven friction plate, thereby releasing the service brake.

9. The electric drive assembly according to claim 7, characterized in that, A floating oil seal is installed between the first housing and the hub body to isolate the first housing from the external environment, and is isolated from the internal oil cavity of the final drive assembly by the floating oil seal.

10. The electric drive assembly according to claim 7, wherein, The service brake also includes a cooling oil inlet, a cooling oil outlet and a housing oil passage that connects the cooling oil inlet with the cooling oil outlet, the housing oil passage is connected to the active friction plate and the driven friction plate, the cooling oil outlet is connected to the oil inlet of the radiator, and the oil outlet of the radiator is connected to the cooling oil inlet to form a cooling circulation oil circuit.

11. The electric drive assembly according to claim 7, characterized in that, There are two cooling oil inlets and two cooling oil outlets respectively, which are symmetrically distributed on the second shell; And / or, there are two pressure oil ports, which are symmetrically arranged on the second housing.

12. An engineering machinery, characterized in that, Comprising the electric drive assembly according to any one of claims 1 to 11.

13. The construction machinery according to claim 12, wherein, It also includes a track wheel, and the sprocket is meshingly and transmission-connected with the track wheel.

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