Wet drive axle with built-in parking and service brakes

Abstract

A wet drive axle with built-in parking and service brakes. Two axle housings (2) are respectively mounted on two sides of a motor (1); one end of a motor shaft (11) is connected to a differential (3) rotatably mounted in the axle housing (2), and a parking brake assembly (4) is provided between the other end of the motor shaft (11) and the axle housing (2); the differential (3) separately transmits the power of the motor (1) to sun gear shafts (61) rotatably mounted in the axle housings (2); a service brake assembly (5) for implementing braking is provided between each sun gear shaft (61) and the corresponding axle housing (2); an inner ring gear (69) is fixed in each axle housing (2), a planet carrier (63) is rotatably connected in the axle housing (2), planet gears (62) are mounted on the planet carrier (63), the planet gears (62) are located in the inner ring gear (69) and are engaged with the inner ring gear (69), and one end of each sun gear shaft (61) is inserted among multiple planet gears (62) and is engaged with the multiple planet gears (62). The position arrangement of a brake structure in a drive axle improves the compactness of internal structure arrangement, making the drive axle smaller.

Description

A wet drive axle with built-in parking and service brakes Technical Field

[0001] The utility model relates to the field of forklift drive axles, in particular to a wet drive axle with built-in parking and service brakes. Background Art

[0002] With the development of the domestic forklift industry, the design and manufacturing of wet drive axles have gradually matured. As one of the primary drive systems used in forklifts of all types, the drive axle is generally divided into service brakes and parking brakes. Service brakes apply braking force to the wheels, thereby slowing or stopping the vehicle; parking brakes ensure parking on flat ground or slopes and can also be used for emergency braking.

[0003] The patent technical document with announcement number CN214028067U discloses a wet-type bridge-box integrated drive axle for forklifts, including a bridge housing, an input assembly, two service brake assemblies, two coaxially distributed half-shafts and two wheel hub assemblies. The bridge housing includes a first shell and two second shells fixedly connected, and the two second shells are respectively located on the left and right sides of the first shell. The service brake assembly is located in the second shell and is sleeved on the half-shafts. The wheel hub assembly is installed at the outer end of the second shell and fixedly connected to the outer end of the half-shaft. The input assembly is installed on the first shell, and the input assembly includes a transversely arranged input shaft and output shaft.

[0004] In the existing technology, most axle housings are used to wrap the half-axles, and the motor and input assembly are arranged on the outside of the axle housing. This arrangement makes it impossible to fully utilize the space inside the drive axle, and more space must be reserved on the vehicle to install the motor and input assembly. Technical issues

[0005] In order to solve the problem of unreasonable drive axle arrangement in the prior art, the purpose of the utility model is to provide a wet drive axle with built-in parking and service brakes. The drive axle has a more compact structure, a fuller internal structure, and supports both service brake and parking brake braking modes. Technical Solutions

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions: a wet drive axle with built-in parking and service brakes, comprising a motor, a bridge housing, a differential and a wheel hub assembly, two bridge housings are respectively mounted on both sides of the motor, two ends of the motor shaft of the motor are respectively extended into the two bridge housings, one end of the motor shaft is connected to the differential rotatably mounted in the bridge housing, a parking brake assembly is arranged between the other end of the motor shaft and the bridge housing, a driving gear shaft is rotatably mounted in the bridge housing, both driving gear shafts are connected to the differential, and the differential transmits the power of the motor to the driving gear shaft respectively; two sets of wheel hub assemblies are respectively mounted in the two bridge housings; the wheel hub assembly comprises a sun gear shaft, a planet carrier, a planetary gear, The driven gear and the inner ring gear; the inner ring gear is fixed in the bridge housing, the inner ring gear is mounted on the planet carrier, the planet carrier is rotatably connected to the bridge housing, one end of the planet carrier extends from the bridge housing and is used as a hub, multiple planetary gears are arranged around the axis of the planet carrier, the planetary gears are rotatably mounted on the planet carrier, the planetary gears are located in the inner ring gear and mesh with each other, the sun gear shaft is rotatably connected to the bridge housing, one end of the sun gear shaft is inserted into multiple planetary gears and meshes with each other, the driven gear is fixed on the sun gear shaft, the driven gear and the driving gear shaft mesh with each other; one end of the sun gear shaft extends into the planet carrier, the sun gear shaft is rotatably connected to the planet carrier, and a service brake assembly for braking is provided between the other end of the sun gear shaft and the bridge housing.

[0007] Preferably, the bridge housing includes a first housing, a second housing and a third housing fixedly connected in sequence, the first housing is connected to the motor, the first housing, the second housing and the third housing enclose a first cavity and a second cavity, the differential and the parking brake assembly are respectively installed in the first cavities of the two bridge housings, the driving gear shaft is installed in the first cavity, and the wheel hub assembly and the service brake assembly are installed in the second cavity.

[0008] Preferably, the differential and the parking brake assembly are respectively installed in the first housings of the two axle housings.

[0009] Preferably, one end of the driving gear shaft is connected to the differential, the middle position of the driving gear shaft is rotatably connected to the second housing through the third bearing, and one end of the driving gear shaft is rotatably connected to the third housing through the fourth bearing.

[0010] Preferably, one end of the sun gear shaft is connected to the service brake assembly, the middle position of the sun gear shaft is rotatably connected to the second housing through the fifth bearing, and the other end of the sun gear shaft is rotatably connected to the planet carrier through the sixth bearing.

[0011] Preferably, the planet carrier is mounted in the bridge housing via two oppositely arranged tapered roller bearings, and the two tapered roller bearings are located on both sides of the planet gear.

[0012] Preferably, a bushing is provided on the planet carrier, and a box-type oil seal for sealing is provided between the bushing and the bridge housing.

[0013] Preferably, a rotating shaft is sleeved on the motor shaft, one driving gear shaft is directly connected to the differential, and the other driving gear shaft is connected to the differential through the rotating shaft.

[0014] Preferably, the parking brake assembly includes a parking brake piston, an inner parking friction plate and an outer parking friction plate. The inner parking friction plate and the outer parking friction plate are both mounted on the motor shaft. The inner parking friction plate is slidingly connected to the motor shaft and circumferentially fixed. The outer parking friction plate is circumferentially fixed to the bridge housing. The parking brake piston is slidingly installed in the bridge housing.

[0015] Preferably, the service brake assembly includes a service brake piston, an inner service friction plate and an outer service friction plate. The inner service friction plate and the outer service friction plate are both mounted on the sun gear shaft. The inner service friction plate is slidingly connected to the sun gear shaft and circumferentially fixed. The outer service friction plate is circumferentially fixed to the bridge housing. The service brake piston is slidingly installed in the bridge housing. Beneficial effects

[0016] The beneficial effects of the technical solution of the present utility model are as follows: in the above solution, the motor is placed in the middle position of the drive axle, and the position of the brake structure in the drive axle is reasonably arranged, which improves the compactness of the internal structure layout, makes the drive axle smaller in size, the internal structure more fuller, the cost lower, and supports both service braking and parking braking modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the drive axle.

[0018] FIG2 is an enlarged view of point A in FIG1.

[0019] FIG3 is an enlarged view of point B in FIG1 .

[0020] FIG4 is a schematic diagram of the connection structure of the axle housing, the parking brake assembly and the wheel hub assembly.

[0021] Figure numerals: 1, motor; 11, motor shaft; 2, bridge housing; 21, first housing; 22, second housing; 23, third housing; 3, differential; 31, differential housing; 32, star gear; 33, left side shaft gear; 34, right side shaft gear; 35, first bearing; 36, second bearing; 4, parking brake assembly; 41, parking piston; 42, parking oil chamber; 43, parking inner friction plate; 44, parking outer friction plate; 45, parking brake end plate; 46, parking return bolt; 47, return bolt seat; 5, driving brake Dynamic assembly; 51, service brake piston; 511, service abutment; 52, service oil chamber; 53, guide pin; 54, return bolt; 55, service inner friction plate; 56, service outer friction plate; 57, service brake end plate; 58, mounting part; 6, wheel hub assembly; 61, sun gear shaft; 62, planetary gear; 63, planetary carrier; 64, driven gear; 65, fifth bearing; 66, sixth bearing; 67, tapered roller bearing; 68, cassette seal; 69, inner ring gear; 71, driving gear shaft; 72, rotating shaft; 73, spline sleeve. Best Mode for Carrying Out the Invention

[0022] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, unless otherwise specified, "plurality" means two or more, unless expressly limited otherwise.

[0025] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0026] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0027] As shown in Figure 1-4, a wet drive axle with built-in parking and service brakes includes a motor 1, a bridge housing 2, a differential 3, and a wheel hub assembly 6; the two bridge housings 2 are fixed on both sides of the motor 1, and the two wheel hub assemblies 6 are respectively installed in the two bridge housings 2, and the differential 3 is installed in the bridge housing 2. The differential 3 is connected to the motor 1 and transmits the power of the motor 1 to the two wheel hub assemblies 6 respectively; the motor shaft 11 of the motor 1 extends into the bridge housing 2, and a parking brake assembly 4 for braking the motor shaft 11 is provided in the bridge housing 2, and a service brake assembly 5 for braking the wheel hub assembly 6 is also installed in the bridge housing 2; the parking brake assembly 4 includes a parking outer friction plate 44, a parking inner friction plate 43, a parking piston 41 and a parking return bolt 46, and the parking outer friction plate 44 and the parking inner friction plate 43 are both sleeved on the motor shaft 11, and the parking outer friction plate 44 is fixed circumferentially to the bridge housing 2 The parking inner friction plate 43 is slidably connected to the motor shaft 11 and circumferentially fixed, the parking outer friction plate 44 and the parking inner friction plate 43 are alternately arranged, the parking piston 41 is slidably installed on the bridge housing 2, a parking oil chamber 42 is set between the parking piston 41 and the bridge housing 2, and the parking return bolt 46 is set between the parking piston 41 and the bridge housing 2; the service brake assembly 5 includes a service outer friction plate 56, a service inner friction plate 55, a service brake piston 51 and a service return bolt 54, the service outer friction plate 56 is circumferentially fixed to the bridge housing 2, the service inner friction plate 55 is slidably connected to the wheel hub assembly 6 and circumferentially fixed, the service outer friction plate 56 and the service inner friction plate 55 are alternately arranged, the service brake piston 51 is slidably installed on the bridge housing 2, a service oil chamber 52 is set between the service brake piston 51 and the bridge housing 5, and the service return bolt 54 is set between the service brake piston 51 and the bridge housing 5.

[0028] With such an arrangement, in this solution, the parking brake and the service brake are separately arranged, the parking brake brakes the motor shaft, and the service brake brakes the wheel hub assembly, which effectively reduces the complexity of the drive axle braking structure. When parking, the parking brake assembly cuts off the power from the power source, thereby effectively organizing the rotation of the shaft system in the drive axle transmission path, and the service brake brakes the power output position of the drive axle, making the braking effect more direct and the braking force more prominent.

[0029] In this embodiment, a driving gear shaft 71 is rotatably mounted in the axle housing 5. The driving gear shafts 71 in the two axle housings 2 are connected to the differential 3. The hub assembly 6 includes a sun gear shaft 61, a planet carrier 63 and a planetary gear 62. The planetary carrier 63 is rotatably mounted in the axle housing 2. One end of the planetary carrier 63 extends from the axle housing 2 and is used as a hub. Multiple planetary gears 62 are rotatably mounted on the planetary carrier 63. The planetary gears 62 are located in the inner gear ring 69 and mesh with each other. The inner gear ring 69 is fixed in the axle housing 2. The sun gear shaft 61 is rotatably mounted in the axle housing 2. One end of the sun gear shaft 61 extends between multiple planetary gears 62 and meshes with each other. The inner friction plate 55 and the outer friction plate 56 of the service brake assembly 5 are both sleeved on the other end of the sun gear shaft 16. The inner friction plate 55 of the planet is splined to the sun gear shaft 16. A driven gear 62 is fixed to the sun gear shaft 61. The driven gear 62 meshes with a driving gear shaft 71 rotatably mounted in the axle housing 2. The driving gear shaft 71 is connected to the differential 3. With such an arrangement, the service brake assembly 5 brakes the end of the sun gear shaft 61, i.e., brakes from the power input of the hub assembly, making the structure of the drive axle more compact and having better braking effect; in the above structure, a driving first-stage reduction structure is formed between the driven gear and the driving gear shaft, and a second-stage reduction structure is formed by the hub assembly, thereby enabling the vehicle to obtain greater torque, and the driving gear shaft and the sun gear shaft are arranged in parallel, so that part of the structure of the parking brake assembly and part of the structure of the service brake assembly can overlap in the axial direction of the motor shaft, thereby making the structure of the drive axle more compact under the premise that the drive axle has both parking brake and service brake.

[0030] Furthermore, the inner ring gear 69 is preferably integrally formed with the axle housing 2. This configuration allows the inner ring gear and the planet carrier to be integrated, resulting in high component strength. Furthermore, the planet gears 62 are preferably mounted on the planetary gear shafts fixed to the planet carrier 63 via double-row needle roller bearings.

[0031] In this embodiment, in order to make the structure of the drive axle more compact, the motor shaft is a hollow shaft, which is loosely sleeved on the rotating shaft. One driving gear shaft is directly connected to the differential, and the other driving gear shaft is connected to the differential via a rotating shaft. Specifically, the specific structure of the differential can be referred to patent technical documents such as publication numbers CN113883252A, CN110145584A, and CN115264023A. In this embodiment, the differential 3 includes a differential housing 31, a left-end half-shaft gear 33, a right-end half-shaft gear 34, and a star gear 32. The differential housing 31 is rotatably connected to the axle housing 2, and the left-end half-shaft gear 33, the right-end half-shaft gear 34, and the star gear 32 are all rotatably mounted on the differential housing. On the body 31, the left side shaft gear 33 and the right side shaft gear 34 are arranged opposite to each other. The left side shaft gear 33 and the right side shaft gear 34 are located on both sides of the planetary gear 32 and mesh with each other for transmission. The driving gear shaft 71 located on the left side of the differential 3 is plugged into the left side shaft gear 33 and spline-matched. The rotating shaft 72 located on the right side of the differential 3 is plugged into the right side shaft gear 34 and spline-matched. The right end of the rotating shaft 72 is rotatably connected to the driving gear shaft 71 located on the right side of the differential 3 through a spline sleeve 73.

[0032] To facilitate assembly of the drive axle, in this embodiment, as shown in Figures 1 to 4 , the axle housing 2 includes a first housing 21, a second housing 22, and a third housing 23, which are fixedly connected in sequence. The first housing 21 is fixedly connected to the motor 1. The first housing 12, the second housing 22, and the third housing 23 are fastened together to form a first cavity and a second cavity. The driving gear shaft 71 is installed in the first cavity. The parking brake assembly 4 and the differential 3 are respectively installed in the first cavities of the two axle housings 2. The service brake assembly 5 and the wheel hub assembly 6 are disposed in the second cavity. This arrangement facilitates assembly of the drive axle.

[0033] To simplify assembly of the drive axle, in this embodiment, as shown in Figures 2 to 4 , the motor shaft 11 of the motor 1 extends at both ends into the first housings 21 of the two axle housings 2, respectively. The differential 2 and parking brake assembly 4 are mounted in the two first housings 21, respectively. The driving gear shaft 71 is rotatably mounted in the second housing 22. The service brake piston 51 is mounted on the first housing 21, the sun gear shaft 61 is rotatably mounted on the second housing 22, and the planetary carrier 63 is mounted on the third housing 23. This arrangement allows the drive axle to be assembled after the various components are installed in their respective housings, thereby facilitating assembly and subsequent maintenance. Furthermore, as shown in Figure 3 , the middle portion of the driving gear shaft 71 is rotatably connected to the second housing 22 via a third bearing 711. One end of the driving gear shaft 71 extends from the second housing 22 and is rotatably connected to the third housing 23 via a fourth bearing 712. This arrangement allows the driving gear shaft to adopt a double-support structure, reducing errors caused by gear transmission and meeting the requirements of light load and high speed.

[0034] In this embodiment, as shown in FIG2 , the first housing 21 in which the differential 3 is mounted has a first opening and a second opening at both ends thereof, communicating with the interior thereof. The first opening faces the motor 1, and the second opening faces the second left housing 22. The inner diameter of the first opening is larger than the inner diameter of the second opening and the outer diameter of the differential 3, while the inner diameter of the second opening is smaller than the outer diameter of the differential 3. The differential housing 32 is provided with two opposing stepped surfaces: a first step protruding from the first opening of the first housing 21, and a second step protruding from the second opening of the first housing 21. A first bearing 35 and a second bearing 36 are mounted on the two stepped surfaces of the differential housing 31, respectively. The first bearing 35 is located in the first opening, and the second bearing 36 is located in the second opening. The left end of the outer ring of the first bearing 35 abuts against the first step in the first opening, the right end of the outer ring of the first bearing 35 abuts against the retaining ring engaged in the first opening, and the left end of the outer ring of the second bearing 36 abuts against the second step in the second opening. This arrangement allows for quick installation of the differential within the first housing.

[0035] In this embodiment, as shown in Figure 3, a cylinder portion 211 is protruded from the first housing 21 in which the parking brake assembly 4 is installed, and a parking abutment portion 411 is protruded from the parking brake piston 41. The parking abutment portion 411 extends into the cylinder portion 211. The bridge housing 2, the cylinder portion 211, the parking abutment portion 411 and the parking brake piston 41 enclose a parking oil chamber 42.

[0036] Furthermore, the cylinder portion 211 is preferably provided with a first brake groove, into which both the inner parking friction plate 43 and the outer parking friction plate 44 are disposed. The parking abutment portion 411 of the parking brake piston 41 can extend into the first brake groove and abut against the friction plates. This arrangement makes the drive axle structure more compact.

[0037] Preferably, the first brake groove is splined to the parking outer friction plate 44. A parking brake end plate 45 is fixed within the axle housing 2. The parking inner friction plate 53 and the parking outer friction plate 44 are positioned between the parking brake end plate 45 and the parking brake piston 41. This arrangement facilitates installation of the parking brake assembly within the axle housing. Preferably, the parking brake end plate 45 is positioned within the first housing 21 near the end of the motor 1. This arrangement effectively limits the length of the motor shaft, resulting in a more compact drive axle structure.

[0038] As shown in Figure 3, a return bolt seat 47 is fixed within the axle housing 2, and a parking brake return bolt 46 is disposed between the parking brake piston 41 and the return bolt seat 47. A first receiving groove is defined in the parking brake piston 41, and a second receiving groove is defined in the return bolt seat 47. The ends of the parking brake return bolt 46 extend into the first and second receiving grooves, respectively. This arrangement stabilizes the movement of the return bolt and makes the drive axle structure more compact.

[0039] In this embodiment, as shown in FIG3 , an oil groove is provided on the first housing 21 facing the second housing 22. One end of the service brake piston 51 is inserted into the oil groove. The service brake piston 51 and the inner wall of the oil groove together form a service oil chamber 52. This arrangement simplifies the structure of the drive axle.

[0040] Further preferably, a mounting portion 58 protrudes from the service brake piston 51, and a plurality of guide pins 53 are inserted through the mounting portion 58. The plurality of guide pins 53 are arranged around the axis of the service brake piston 51. The guide pins 53 slideably engage with the mounting portion 58. One end of the guide pin 53 passes through the mounting portion 58 and is threadedly connected to the first housing 21. The other end of the guide pin 53 has a protruding head. A return bolt 54 is sleeved on the guide pin 53. One end of the return bolt 54 abuts against the head of the guide pin 53, and the other end of the return bolt 54 abuts against the mounting portion 58. Further preferably, a plurality of third receiving slots are defined in the mounting portion 58. The third receiving slots correspond one to one with the guide pins. The guide pins 53 pass through the third receiving slots, and one end of the return bolt 54 extends into the third receiving slot and abuts against the inner wall of the third receiving slot.

[0041] In this embodiment, the second housing 22 is provided with a second brake groove opening toward the first housing 21. Both the driving inner friction plate 55 and the driving outer friction plate 56 are disposed within the second brake groove, with the driving outer friction plate 56 being spline-connected to the second brake groove. This arrangement makes the drive axle structure more compact.

[0042] Further preferably, a service brake end plate 47 is provided in the second brake groove, the service brake end plate 47 is spline-connected to the second brake groove, and a service abutment portion 511 is raised on the mounting portion 58 of the service brake piston 51 for pushing the service brake end plate 57, and the service brake end plate 57 is located between the service abutment portion 511 and the friction plate.

[0043] In this embodiment, as shown in Figure 4 , a connecting portion is provided on the driven gear 64. The connecting portion is mounted on and fixed to the sun gear shaft 61. The service brake inner friction plate 55 and the service brake outer friction plate 56 are both mounted on the connecting portion. The service brake inner friction plate 55 is spline-connected to the connecting portion. The connecting portion is rotatably connected to the second housing 55 via a fifth bearing 65. This arrangement provides more stable installation of the sun gear shaft.

[0044] Preferably, one end of the sun gear shaft 61 extends into the planet carrier 63, and the two are rotatably connected via a sixth bearing 66. This arrangement allows the drive axle to carry a greater load. Furthermore, the planet gears 62 and the ring gear 69 engage with helical gears. This arrangement, with the planet gears supported on both sides by tapered roller bearings and the helical gear transmission, effectively improves the drive axle's load-bearing capacity and reduces noise.

[0045] In this embodiment, the planet carrier 63 is rotatably mounted on the third housing 23 via two opposing tapered roller bearings 67. Specifically, the two tapered roller bearings 67 are located on either side of the planet gear 62 and the inner ring gear 69. The outer rings of the two tapered roller bearings 67 clamp the inner ring gear 69. A sealing portion is raised on the planet carrier 63, and a nut is threaded onto the planet carrier 63. The nut is located near the second housing 22. The two tapered roller bearings 67 are located between the nut 601 and the sealing portion. The inner ring of one tapered roller bearing 67 abuts the sealing portion, while the inner ring of the other tapered roller bearing 67 abuts the nut 601. This arrangement shortens the distance between the nut 601 and the sealing portion, causing the outer rings of the two tapered roller bearings 67 to clamp the inner ring gear 69, thereby fixing the position of the planet carrier 63. Furthermore, two large-sized tapered roller bearings are arranged back-to-back between the ring gear and the planet carrier to improve the support rigidity of the drive axle.

[0046] Further preferably, a locking plate 602 is fixed to the end of the planet carrier 63 , and the locking plate 6002 abuts against the nut 601 and prevents the nut 601 from rotating.

[0047] In this embodiment, a bushing 603 is sleeved over the sealing portion, and a cartridge seal 68 is positioned between the bushing 603 and the third housing 23. This arrangement enhances the hub assembly's anti-fouling capabilities and extends its service life. The sealing lip is located within the oil seal, reducing the requirements for housing roughness and saving processing costs. The seal also offers excellent manufacturability and simplifies installation, preventing damage to the seal lip and oil leakage caused by misoperation during installation.

[0048] When the drive axle is in motion: the parking oil chamber 42 is filled with oil, the pressure oil in the parking oil chamber 42 pushes the parking piston 41 to move, the parking return bolt 56 is compressed, and the parking inner friction plate 43 and the parking outer friction plate 44 are separated; the driving oil chamber 52 is not filled with oil, the driving return bolt 54 pushes the parking brake piston 51 to move, and the driving inner friction plate 55 and the driving outer friction plate 56 are separated; the motor 1 drives the motor shaft 11 to rotate, and the motor shaft 11 drives the differential housing 31 and the parking inner friction plate 43 to rotate, and the differential housing 31 is connected to the driving shaft 11 through the star gear. 32 drives the left sideshaft gear 33 and the right sideshaft gear 34 to rotate. The left sideshaft gear 33 drives the driving gear shaft 71 on the left to rotate. The right sideshaft gear 34 drives the driving gear shaft 71 on the right to rotate through the rotating shaft 72 and the spline sleeve 73. The driving gear shaft 71 drives the driven gear 64 to rotate. The driven gear 64 drives the sun gear shaft 61 to rotate. The sun gear shaft 61 drives the planetary gears 62 to rotate. The planetary gears 62 rotate and rotate around the axis of the sun gear shaft 61 under the action of the inner ring gear 69, thereby driving the planetary carrier 63 to rotate.

[0049] When the drive axle is braking during driving: the parking oil chamber 42 is filled with oil, and the pressure oil in the parking oil chamber 42 pushes the parking piston 41 to move, the parking return bolt 56 is compressed, and the parking inner friction plate 43 and the parking outer friction plate 44 are separated; the driving oil chamber 52 is filled with oil, and the pressure oil in the driving oil chamber 52 pushes the driving brake piston 51 to move, the driving return bolt 54 is compressed, and the driving brake piston 51 drives the driving inner friction plate 55 and the driving outer friction plate 56 to engage and lock the sun gear shaft 61, thereby applying brakes to the sun gear shaft 61;

[0050] When the drive axle is parked during the parking process: the parking return bolt 46 pushes the parking piston 41 to move, driving the parking oil chamber 42 to drain oil, and driving the service brake piston 41 to drive the parking inner friction plate 43 and the parking outer friction plate 44 to combine to lock the motor shaft 11, thereby braking the motor shaft 11; the driving oil chamber 52 is not filled with oil, the driving return bolt 54 pushes the driving brake piston 51 to move, and the driving inner friction plate 55 and the driving outer friction plate 56 are separated.

[0051] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0052] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A wet drive axle with built-in parking and service brakes, characterized in that: The invention comprises a motor (1), a bridge housing (2), a differential (3) and a wheel hub assembly (6), wherein the two bridge housings (2) are respectively mounted on both sides of the motor (1), the two ends of a motor shaft (11) of the motor (1) respectively extend into the two bridge housings (2), one end of the motor shaft (11) is connected to a differential (3) rotatably mounted in the bridge housing (2), and a parking brake assembly (4) is arranged between the other end of the motor shaft (11) and the bridge housing (2); a driving gear shaft (71) is rotatably mounted in the bridge housing (2), the two driving gear shafts (71) are both connected to the differential (3), and the differential (3) transmits the power of the motor (1) to the driving gear shaft (71) respectively; two sets of wheel hub assemblies (6) are respectively mounted in the two bridge housings (2); the wheel hub assembly (6) comprises a sun gear shaft (61), a planet carrier (63), a planetary gear (62), a driven gear (64) and an inner gear ring (69); the inner gear ring (69) is fixed in the bridge housing (2), and the inner gear ring (69) is fixed in the bridge housing (2). The ring gear (69) is sleeved on the planet carrier (63), the planet carrier (63) is rotatably connected to the bridge housing (2), one end of the planet carrier (63) extends from the bridge housing (2) and is used as a wheel hub, a plurality of planetary gears (62) are arranged around the axis of the planet carrier (63), the planetary gears (62) are rotatably mounted on the planet carrier (63), the planetary gears (62) are located in the inner ring gear (69) and mesh with each other, the sun gear shaft (61) is rotatably connected to the bridge housing (2), and the sun gear One end of the shaft (61) is inserted into a plurality of planetary gears (62) and meshes with each other; a driven gear (64) is fixed on the sun gear shaft (61); the driven gear (64) and the driving gear shaft (71) mesh with each other; one end of the sun gear shaft (61) extends into the planetary carrier (63); the sun gear shaft (61) and the planetary carrier (63) are rotatably connected; a service brake assembly (5) for applying braking is provided between the other end of the sun gear shaft (61) and the bridge housing (2).

2. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: The axle housing (2) comprises a first housing (21), a second housing (22) and a third housing (23) which are fixedly connected in sequence, the first housing (21) being connected to the motor (1), the first housing (21), the second housing (22) and the third housing (23) enclosing a first cavity and a second cavity, the differential (3) and the parking brake assembly (4) being respectively mounted in the first cavities of the two axle housings (2), the driving gear shaft (71) being mounted in the first cavity, and the wheel hub assembly (6) and the service brake assembly (5) being mounted in the second cavity.

3. A wet drive axle with built-in parking and service brakes according to claim 2, characterized in that: The differential (3) and the parking brake assembly (4) are respectively mounted in the first housings (21) of the two bridge housings (2).

4. A wet drive axle with built-in parking and service brakes according to claim 2, characterized in that: One end of the driving gear shaft (71) is connected to the differential (3), the middle position of the driving gear shaft (71) is rotatably connected to the second housing (22) via a third bearing (711), and one end of the driving gear shaft (71) is rotatably connected to the third housing (23) via a fourth bearing (712).

5. A wet drive axle with built-in parking and service brakes according to claim 2, characterized in that: One end of the sun gear shaft (61) is connected to the service brake assembly (5), the middle position of the sun gear shaft (61) is rotatably connected to the second housing (22) via a fifth bearing (65), and the other end of the sun gear shaft (61) is rotatably connected to the planet carrier (63) via a sixth bearing (66).

6. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: The planet carrier (63) is installed in the bridge housing (2) via two tapered roller bearings (67) arranged opposite to each other, and the two tapered roller bearings (67) are located on both sides of the planet gear (62).

7. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: A bushing (603) is sleeved on the planet carrier, and a box-type oil seal (68) for sealing is provided between the bushing (603) and the bridge housing (2).

8. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: A rotating shaft (72) is hollowly sleeved on the motor shaft (11), one driving gear shaft (71) is directly connected to the differential (3), and the other driving gear shaft (71) is connected to the differential (3) via the rotating shaft (72).

9. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: The parking brake assembly (4) comprises a parking brake piston (41), an inner parking friction plate (43) and an outer parking friction plate (44); the inner parking friction plate (43) and the outer parking friction plate (44) are both sleeved on the motor shaft (11); the inner parking friction plate (43) is slidably connected to the motor shaft (11) and circumferentially fixed; the outer parking friction plate (44) is circumferentially fixed to the bridge housing (2); and the parking brake piston (41) is slidably mounted in the bridge housing (2).

10. A wet drive axle with built-in parking and service brakes according to claim 1, characterized in that: The service brake assembly (5) comprises a service brake piston (51), an inner friction plate (55) and an outer friction plate (56). The inner friction plate (55) and the outer friction plate (56) are both sleeved on a sun gear shaft (61). The inner friction plate (55) is slidably connected to the sun gear shaft (61) and circumferentially fixed. The outer friction plate (56) is circumferentially fixed to the axle housing (2). The service brake piston (51) is slidably mounted in the axle housing (2).

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