Wet type parking brake and service brake integrated electric drive axle assembly

Abstract

The utility model discloses an electric drive axle assembly integrating wet type parking braking and service braking. The electric drive axle assembly comprises a motor, an axle housing, a differential mechanism and a hub unit assembly. The two axle housings are fixed to the two sides of the motor respectively, and the hub unit assemblies are installed on the two axle housings respectively. The differential mechanism transmits power of the motor to the driving gear shafts rotationally installed in the two axle housings, and the power of the driving gear shafts is output through the hub unit assemblies. A service braking assembly and a parking braking assembly which are used for implementing braking of the driving gear shaft are further mounted in the axle housing; the friction plate is arranged between the driving gear shaft and the axle housing; the parking brake piston and the service brake piston are installed in the axle housing in a sliding mode, and when the parking brake piston moves, the service brake piston can be driven, so that the friction part drives the inner friction plate and the outer friction plate to be combined to implement braking. According to the arrangement, traveling braking and parking braking both act on the same position of the friction plate, so that the braking effect of the drive axle is improved, and the radial size of the drive axle is reduced.

Description

Technical Field

[0001] The utility model relates to the field of drive axles, in particular to an electric drive axle assembly integrating a wet parking brake and a service brake. Background Art

[0002] With the development of my country's logistics economy, forklifts are becoming more commonplace, and the design and manufacturing of forklift transmission components are gradually maturing. As forklifts move toward new energy sources, transmission components are also trending toward integrated designs. Existing domestic drive axle motor axes are arranged horizontally or vertically outside the drive axle box. This results in a significant amount of space occupied by the drive system in both horizontal and vertical directions, complicating overall vehicle layout.

[0003] The prior art with publication number CN221113493U discloses an electric drive axle assembly with wet parking brake and service brake. The two axle housings are fixed on both sides of the motor respectively, and the two reducer housings are installed in the two axle housings respectively; the axle housing is also equipped with a service brake assembly and a parking brake assembly for implementing the braking of the driving gear shaft; the service brake assembly includes a service brake piston, a service oil cylinder body and a return spring for driving the service brake piston to reset; the service oil cylinder body is fixed on the axle housing, and the service brake piston is slidably mounted on the service oil cylinder body, and a service oil chamber is provided between the service brake piston and the service oil cylinder body; when the service oil chamber is filled with oil, the service brake piston approaches and pushes the inner friction plate, so that the inner friction plate, the outer friction plate and the axle housing are pressed. The housings are pressed against each other; when the driving oil chamber leaks oil, the return spring pushes the parking brake piston away from the inner friction plate, so that the inner friction plate, outer friction plate and bridge housing are separated from each other; the parking brake assembly includes a parking brake piston, a parking oil cylinder body and a parking spring for driving the parking brake piston to reset; the parking oil cylinder body is fixed on the bridge housing, and the parking brake piston is slidably mounted on the parking oil cylinder body, and a parking oil chamber is provided between the parking brake piston and the parking oil cylinder body; when the parking oil chamber is filled with oil, the parking brake piston is away from the inner friction plate, so that the inner friction plate, outer friction plate and bridge housing are separated from each other; when the parking oil chamber leaks oil, the parking spring pushes the parking brake piston, so that the parking brake piston approaches and pushes the inner friction plate, so that the inner friction plate, outer friction plate and bridge housing are pressed against each other.

[0004] In the existing technical group, the driving axle uses a service brake piston for driving braking, and a parking brake piston for parking braking. To ensure the braking effect, the service brake piston and the parking brake piston need to have appropriate widths respectively. In this way, the radial size of the driving axle needs to be increased to accommodate the service brake piston and parking brake piston arranged inside and outside. Utility Model Content

[0005] In order to solve the problems in the prior art that the braking effect of the drive axle is general and the radial size of the drive axle is large, the purpose of the utility model is to provide an electric drive axle assembly integrating a wet parking brake and a service brake. Both the service brake and the parking brake act on the same position of the friction plate, which can improve the braking effect of the drive axle while reducing the radial size of the drive axle.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solutions: an electric drive axle assembly with integrated wet parking brake and service brake, comprising a motor, a bridge housing, a differential, and a hub unit assembly; two bridge housings are fixed on either side of the motor, and the hub unit assemblies are mounted on the two bridge housings; a differential is mounted in one bridge housing and is in driving connection with the motor, the differential transmitting the power of the motor to driving gear shafts rotatably mounted in the two bridge housings, and the power of the driving gear shafts is output through the hub unit assembly; a service brake assembly and a parking brake assembly for braking the driving gear shaft are also mounted in the bridge housing; The driving gear shaft is sleeved with inner friction plates and outer friction plates arranged alternately, the inner friction plates are slidably connected to the driving gear shaft, and the outer friction plates are slidably connected to the bridge housing; the service brake assembly includes a service brake piston slidably mounted in the bridge housing, and the parking brake assembly includes a parking brake piston slidably mounted in the bridge housing, and the service brake piston has a friction portion protruding from one end facing the friction plate, and the friction portion is located between the parking brake piston and the friction plate; when the service brake piston moves, the friction portion can drive the inner friction plate and the outer friction plate to combine to implement braking; when the parking brake piston moves, the friction portion can drive the inner friction plate and the outer friction plate to combine to implement braking.

[0007] Preferably, the service brake piston is located inside the parking brake piston.

[0008] Preferably, the service brake assembly also includes a service oil cylinder body and a return spring for driving the service brake piston to reset; the service oil cylinder body is fixed on the bridge housing, the service brake piston is slidably mounted on the service oil cylinder body, and a service oil chamber is provided between the service brake piston and the service oil cylinder body.

[0009] Preferably, a second connecting portion protrudes from the inner friction plate on the service oil cylinder body, and the second connecting portion is located on the inner side of the parking brake piston. A first accommodating groove is provided on the end face of the second connecting portion close to the inner friction plate. The first accommodating groove is a step groove, and part of the service brake piston is inserted into the first accommodating groove and matches the first accommodating groove. The stepped first accommodating groove and the service brake piston enclose a service oil chamber.

[0010] Preferably, a fourth accommodating groove is provided on the service brake piston, a plurality of through holes are provided in the fourth accommodating groove, and a threaded hole coaxial with the through hole is provided in the first accommodating groove of the service oil cylinder body; the return bolt includes a head, an intermediate connecting portion and a threaded portion connected in sequence, and the return spring of the service brake assembly is sleeved on the intermediate connecting portion, and the threaded portion of the return bolt passes through the through hole and is threadedly connected to the threaded hole on the service oil cylinder body, and part of the intermediate connecting portion extends into the through hole of the service brake piston, and the two ends of the return spring respectively resist the head of the return bolt and the service brake piston.

[0011] Preferably, in the service oil chamber, a third oil seal is provided between the second abutting portion and the first accommodating groove, and a fourth oil seal is provided between the service brake piston and the inner wall of the first accommodating groove.

[0012] Preferably, the parking brake assembly includes a parking brake piston, a parking oil cylinder body and a parking spring for driving the parking brake piston to reset; the parking oil cylinder body is fixed on the bridge housing, the parking brake piston is slidably mounted on the parking oil cylinder body, a parking oil chamber is provided between the parking brake piston and the parking oil cylinder body, and the friction part is located between the service brake piston and the friction plate.

[0013] Preferably, a first connecting portion protrudes inwardly on the parking oil cylinder body, and a first abutting portion protrudes inwardly on the friction plate of the parking brake piston. The first abutting portion is located on the inner side of the first connecting portion, and the first abutting portion can extend from the inner side of the first connecting portion and abut against the friction portion. The parking oil cylinder body, the first connecting portion, the first abutting portion and the parking brake piston form a parking oil chamber.

[0014] Preferably, the parking brake piston is located between the first connecting portion and the driving oil cylinder body, a second accommodating groove is provided on the parking brake piston, a third accommodating groove is provided on the driving oil cylinder body, the parking spring is located between the second accommodating groove and the third accommodating groove, and the two ends of the parking spring are respectively against the inner wall of the second accommodating groove and the inner wall of the third accommodating groove.

[0015] Preferably, in the parking oil chamber, a first oil seal is provided between the first connecting portion and the first abutting portion, and a second oil seal is provided between the parking brake piston and the parking oil cylinder body.

[0016] The beneficial effects of the technical solution of the utility model are as follows: the center lines of the motor, differential, service brake and parking brake are on one axis, which makes the overall layout of the drive axle compact, facilitates the structural arrangement of the forklift and reduces production costs.

[0017] During service braking, both the service brake piston and the parking brake piston act on the friction plate through the friction part. In this way, both the service brake and the parking brake act on the same position of the friction plate. It is only necessary to control the size of the friction part to ensure sufficient braking effect of the drive axle. While improving the braking effect of the drive axle, the radial size of the drive axle can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the drive axle structure Figure 1 ;

[0019] Figure 2 Schematic diagram of the drive axle structure Figure 2 ;

[0020] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0021] Figure 4 A schematic diagram of the connection structure of the service brake mechanism, parking brake mechanism, axle housing and rotating gear shaft;

[0022] Figure 5 A schematic diagram of the connection structure of the service brake mechanism, parking brake mechanism, axle housing, differential, and rotating gear shaft;

[0023] Figure 6 It is a schematic diagram of the connection structure of the service brake mechanism, parking brake mechanism and axle housing;

[0024] Figure 7 Schematic diagram of the connection structure of the bridge housing, driving gear shaft and hub unit assembly.

[0025] Reference numerals: 1, motor; 11, drive shaft; 12, spline sleeve; 13, rotating shaft;

[0026] 21. Axle housing; 211. First mounting slot; 22. Driving gear shaft; 222. Sixth bearing; 23. Brake hub; 24. Outer friction plate; 25. Inner friction plate; 26. End plate; 27. Guide pin; 28. Release spring; 29. ​​First bearing; 20. First retaining ring; 201. Second retaining ring;

[0027] 31. Parking oil cylinder; 311. Parking oil inlet; 32. First connecting portion; 33. Parking brake piston; 34. First abutting portion; 35. Parking oil chamber; 36. Parking spring; 37. Parking brake oil inlet connector;

[0028] 41. Service oil cylinder; 411. Service oil inlet; 42. Second connecting portion; 43. Service brake piston; 431. Friction portion; 44. Service oil chamber; 45. Return bolt; 46. Return spring; 47. Service brake oil inlet connector;

[0029] 5. Differential; 51. Differential housing; 52. Right side gear; 53. Left side gear; 54. Locating pin; 55. Star gear; 56. Differential bearing seat; 57. Third retaining ring; 58. Eighth bearing; 59. Ninth bearing;

[0030] 6. Hub unit assembly; 61. Reducer housing; 611. Internal gear; 62. Driven gear; 63. Sun gear shaft; 631. Fourth bearing; 632. Third bearing; 64. Planetary gear shaft; 641. Oil hole; 642. Retaining ring; 65. Planetary gear; 651. Double-row needle roller bearing; 66. Nut; 67. Locking plate; 68. Tapered roller bearing; 69. Fifth oil seal; 691. Bushing;

[0031] 71. Exhaust connector; 72. Refueling vent plug. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail, 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 be used to explain the present invention, and are not to be construed as limiting the present invention.

[0033] 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 orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 therefore should not be understood as limiting the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify 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 the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0035] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] 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. Furthermore, 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. Example

[0037] like Figures 1 to 7 The electric drive axle assembly with integrated wet parking brake and service brake is shown, including a drive assembly, a differential 5, a bridge assembly and a hub unit assembly 6; the drive assembly includes a motor 1 and a drive shaft 11 for inputting power; the bridge assembly includes a bridge housing 21, a driving gear shaft 22 and a braking mechanism for braking the driving gear shaft 22, the driving gear shaft 22 is rotatably mounted in the bridge housing 21, and the braking mechanism is installed between the bridge housing 21 and the driving gear shaft 22; two sets of bridge assemblies are arranged on both sides of the motor 1, and the bridge housing 21 of the bridge assembly is fixedly connected to the motor housing 1 of the motor 1; the differential 5 is arranged on one of them Inside the bridge housing 21 of the bridge body assembly, the drive shaft 11 transmits power to the driving gear shafts 22 of the two groups of bridge body assemblies through the differential; wherein, the drive shaft 11 and the driving gear shaft 22 are coaxially arranged; the two groups of hub unit assemblies 6 are respectively installed on the two groups of bridge body assemblies; the hub unit assembly 6 includes a reducer housing 61 and a planetary carrier 60, the reducer housing 61 is fixed on the bridge housing 21, and the planetary carrier 60 is rotatably installed on the reducer housing 61, and the planetary carrier 60 is transmission-connected to the driving gear shaft 22; wherein, the axis of the planetary carrier 60 is arranged parallel to the axis of the driving gear shaft 22, and the planetary carrier 60 is used as a hub.

[0038] With such an arrangement, the present invention adopts a single motor 1 integrated with distributed differential technology, and two braking mechanisms are arranged on both sides of the motor 1. The driving gear shaft 22 and the drive shaft 11 for transmission and braking are arranged in parallel, and the planetary carrier 60 and the drive shaft 11 for connecting the wheel hub are arranged in parallel. This makes the structure of the drive axle more compact, the braking effect is better, the transmission efficiency is higher, the weight of the forklift is lower, the battery layout space is increased, and the vehicle's cruising range is effectively improved; and the structure of the hub unit assembly 6 for driving the wheel is simpler, the hub unit assembly 6 is more convenient to maintain, so that the distance between the wheel and the ground can be better, thereby making the forklift better able to cope with complex paths.

[0039] In this embodiment, Figure 3 and Figure 5 As shown, the drive shaft 11 is hollow, and the rotating shaft 13 passes through the inner side of the drive shaft 11; wherein, the specific structure of the differential can refer to the patent technical documents such as publication number CN113883252A, CN110145584A and CN115264023A. Specifically, in this embodiment, the differential 5 includes a differential housing 51, a left end half-shaft gear 53, a right end half-shaft gear 52 and a star gear 55. The left end of the differential housing 51 is rotatably connected to the differential bearing seat 56 through the eighth bearing 58, and the right end of the differential housing 51 is rotatably connected to the driving oil cylinder body 41 through the ninth bearing 59. The driving oil cylinder body 41 is fixedly connected to the bridge housing 21, and the differential bearing seat 56 is tightly matched with the bridge housing 21. Two third bearings are fixed in the bridge housing. Three clamping rings 57, the differential bearing seat 56 is located between the two third clamping rings 57, and the two ends of the differential bearing seat 56 are respectively against the two third clamping rings 57, the left side shaft gear 53 and the right side shaft gear 52 are rotatably arranged relative to each other, the left side shaft gear 53 and the right side shaft gear 52 are rotatably installed on the differential housing 51, the left side shaft gear 53, the right side shaft gear 52, the drive shaft 11 and the driving gear shaft 22 are coaxially arranged, a locating pin 54 is fixed in the differential housing 51, and the planetary gear 55 is rotatably installed on the locating pin, the planetary gear 55 is located between the left side shaft gear 53 and the right side shaft gear 52, the planetary gear 55 is meshed with the left side shaft gear 53 and the right side shaft gear 52, and the drive shaft 11 is splined to the differential housing 51. The driving gear shaft 22 of the axle body assembly on the left side is inserted into the center hole of the left end half-shaft gear 53 of the differential and meshed; the left end of the rotating shaft 13 is inserted into the center hole of the right end half-shaft gear 52 of the differential and splined, and the rotating shaft 13 passes through the drive shaft 11 and is connected to the driving gear shaft 22 of the axle body assembly on the right side through the spline sleeve 12.

[0040] In this embodiment, Figure 2 and Figure 7As shown, the hub unit assembly 6 also includes a sun gear shaft 63 and a planetary gear 65. The sun gear shaft 63 is rotatably mounted in the reducer housing 61. The sun gear shaft 63 is coaxially arranged with the planetary carrier 60. The sun gear shaft 63 is meshed with the driving gear shaft 22. The sun gear shaft 63 is meshed with the planetary gear 65 rotatably mounted on the planetary carrier 60. The planetary gear 65 is rotatably mounted on the planetary carrier via the planetary gear shaft 64. An annular internal tooth portion 611 is provided in the reducer housing 61. The planetary gear is located on the inner side of the internal tooth portion. The planetary gear 65 is also meshed with the internal tooth portion of the reducer housing 61. With this arrangement, the internal tooth portion serves as an inner ring gear. The inner ring gear and the planetary carrier adopt an integrated design, and the parts have high strength. The hub unit assembly 6 forms a reduction structure, and the structure of the hub unit assembly 6 used to drive the wheel is simpler.

[0041] Further preferably, a driven gear 62 is fixed to the sun gear shaft 63, and the driven gear 62 is meshed with the driving gear shaft 22. This arrangement forms a reduction structure between the motor 1 and the planetary carrier 60, thereby enabling the drive axle to obtain greater torque and improve the load bearing capacity of the drive axle.

[0042] Furthermore, planet carrier 60 is preferably rotatably mounted on reducer housing 61 via two sets of tapered roller bearings 68, which are symmetrically arranged on either side of planet gear 65. This arrangement employs two large-sized tapered roller bearings arranged back-to-back between the ring gear and the planet carrier, enhancing the support rigidity of the drive axle. The planet gears are supported on both sides with helical gears, increasing load capacity and reducing noise, allowing the drive axle to withstand greater loads.

[0043] In order to make the structure of the drive axle more compact, in this embodiment, Figures 3 to 5 As shown, a first mounting groove 211 is provided on the end surface of the bridge housing 21 close to the reducer housing 61. The reducer housing 61 is fixed to the bridge housing 21 by bolts and covers the first mounting groove 211, thereby enclosing the first mounting groove 211 and the internal space of the reducer housing 61 into a cavity. One end of the driving gear shaft 22 extends into the first mounting slot 211 and is rotatably connected to the reducer housing 61 via the sixth bearing 222, a cylindrical roller bearing. The driving gear shaft 22 is rotatably connected to the axle housing 21 via the first bearing 29, a double-row angular contact ball bearing. This dual-support structure reduces gear transmission errors and is suitable for light-load, high-speed applications. One end of the sun gear shaft 63 extends into the first mounting slot 211. The driven gear 62 is located in the first mounting slot 211 and is rotatably connected to the axle housing 21 via the third bearing 632. The other end of the sun gear shaft 63 extends into the planetary carrier 60 and is rotatably connected to the planetary carrier 60 via a cylindrical roller bearing, thereby securing the sun gear shaft 63 within the drive axle. The third bearing 632 is a ball bearing.

[0044] In this embodiment, the tapered roller bearing 68 is fixed in the following manner: a middle hole is opened on the end of the planetary carrier 60 close to the bridge housing 21, the end of the sun gear shaft 63 extends into the middle hole and is rotatably connected through the fourth bearing 631; the planetary carrier 60 is a stepped shaft, and the planetary carrier 60 includes a first step, a second step and a third step with gradually increasing outer diameters. The first step and the second step extend into the reducer housing 61, and a second mounting groove for mounting the planetary gear 65 is opened on the first step. The second mounting groove is connected to the middle hole, and some planetary gears 65 are connected to the middle hole. 5 is sunk into the second mounting groove and is rotatably connected to the planet carrier 60; part of the planet gear 65 extends from the planet carrier 60 and meshes with the internal teeth of the reducer housing 61, and part of the planet gear 65 extends into the opening of the planet carrier 60 and meshes with the external teeth of the sun gear shaft 63; a positioning groove for mounting the planet gear shaft 64 is also formed on the end surface of the planet carrier 60 near the bridge housing 21. The positioning groove passes through the second mounting groove, and the planet gear shaft is inserted into the positioning groove. The planet gear shaft passes through the second mounting groove and the center hole of the planet gear, and the planet gear shaft is tightly fitted with the positioning groove; Figure 7 As shown, the planetary gear 65 is rotatably mounted on the planetary gear shaft 64 via a second bearing. The second bearing is located in the second mounting groove and is a double-row needle roller bearing 651. The planetary gear shaft 64 is provided with an oil hole 641. One end of the oil hole 641 communicates with the interior of the reducer housing, while the other end of the oil hole 641 fills the double-row needle roller bearing with oil. This arrangement effectively lubricates and cools the hub unit assembly 6, ensuring the stability of the drive axle.

[0045] In this embodiment, two retaining rings 642 are mounted on the planetary gear shaft 64, with the double-row needle roller bearing and the planetary gear 65 positioned between the two retaining rings. This arrangement effectively limits the position of the double-row needle roller bearing and the planetary gear, preventing interference between the planetary carrier, the double-row needle roller bearing, and the tapered roller bearing.

[0046] In order to facilitate limiting the position of the tapered roller bearings, in this embodiment, the two tapered roller bearings 68 are arranged symmetrically face to face, and the outer rings of the two tapered roller bearings 68 are respectively abutted against the two ends of the inner tooth portion of the reducer housing 61, the inner ring of one tapered roller bearing 68 is tightly abutted against the raised secondary step on the planetary carrier 60, and the inner ring of the other tapered roller bearing 68 is abutted against the nut 66 threadedly connected to the planetary carrier 60, and the two tapered roller bearings 68 are located between the nut 66 and the step portion of the planetary carrier 60; with this arrangement, the installation and positioning of the tapered roller bearings 68 are more convenient, and will not interfere with the movement of the planetary gear 65.

[0047] Furthermore, a locking plate 67 is preferably fixedly mounted on the end of the planetary carrier 60 near the axle housing 21. The locking plate 67 compresses the nut 66. The edge of the locking plate 67 is bent to form a locking portion. When the locking plate 67 is fixed to the planetary carrier 60, the nut 66 is located within the locking portion, and the locking portion abuts against the side of the nut 66, thereby preventing the nut 66 from rotating. This arrangement effectively prevents the nut 66 from loosening and improves the stability of the drive axle.

[0048] In this embodiment, Figure 1 and Figure 2 As shown, the drive axle is a wet drive axle, and the drive axle is filled with oil. A refueling vent hole communicating with the interior of the axle housing 21 is provided, and a refueling vent plug 72 is installed on the refueling vent hole.

[0049] In order to prevent oil leakage from the hub unit assembly 6, in this embodiment, a bushing 691 is sleeved on the secondary step of the planetary carrier, and a fifth oil seal 69 is provided between the bushing 691 and the reducer housing 61. The fifth oil seal 69 is a fluororubber oil seal.

[0050] The above-mentioned brake mechanism is an integrated mechanism of service brake and parking brake, such as Figures 2 to 5 As shown, the brake mechanism includes an inner friction plate 25, an outer friction plate 24, a service brake assembly, and a parking brake assembly; the driving gear shaft 22 is rotatably mounted in the axle housing 21, and the outer friction plates 24 and the inner friction plates 25 are both sleeved on the driving gear shaft 22, with multiple outer friction plates 24 and multiple inner friction plates 25 alternately arranged. The outer friction plates 24 are slidably connected to the axle housing 21 and circumferentially fixed, and the inner friction plates 25 are slidably connected to the driving gear shaft 22 and circumferentially fixed;

[0051] like Figure 2 、 Figure 4 and Figure 5 As shown, the service brake assembly includes a service brake piston 43, a service oil cylinder body 41 and a return spring 46 for driving the service brake piston 43 to return to its original position; the service oil cylinder body 41 is fixed to the axle housing 21, and the service brake piston 43 is slidably mounted on the service oil cylinder body 41. A service oil chamber 44 is provided between the service brake piston 43 and the service oil cylinder body 41, and a friction portion 431 is raised on the end plate of the service brake piston 43; when the service oil chamber 44 is filled with oil, the friction portion 431 of the service brake piston 43 approaches and pushes the inner friction plate 25, so that the inner friction plate 25, the outer friction plate 24 and the axle housing 21 are tightly pressed against each other; when the service oil chamber 44 is drained, the return spring 46 pushes the service brake piston 43, so that the friction portion 431 is away from the inner friction plate 25, so that the inner friction plate 25, the outer friction plate 24 and the axle housing 21 are separated from each other;

[0052] The parking brake assembly includes a parking brake piston 33, a parking oil cylinder 31 and a parking spring 36 for driving the parking brake piston 33 to reset; the parking oil cylinder 31 is fixed to the bridge housing 21, and the parking brake piston 33 is slidably mounted on the parking oil cylinder 31. A parking oil chamber 35 is provided between the parking brake piston 33 and the parking oil cylinder 31, and the friction portion 431 is located between the service brake piston 43 and the friction plate; when the parking oil chamber 35 is drained, the parking spring 36 pushes the parking brake piston 33, and the parking brake is released. The brake piston 33 pushes the friction portion 431 of the vehicle brake piston 43, causing the friction portion 431 to approach and push the inner friction plate 25, so that the inner friction plate 25, the outer friction plate 24 and the bridge housing 21 are pressed against each other; when the parking oil chamber 35 is filled with oil, the oil drives the parking brake piston 33 away from the friction portion 431 of the service brake piston 43, and the return spring 46 pushes the vehicle brake piston 43, causing the friction portion 431 to move away from the inner friction plate 25, so that the inner friction plate 25, the outer friction plate 24 and the bridge housing 21 are separated from each other.

[0053] In this way, the above scheme integrates the parking brake structure with the service brake structure, thereby slowing down the vehicle's braking structure and making the structure of the drive axle more compact; in the above scheme, service braking and parking braking are achieved through a set of friction plates, which reduces the number of friction plates used, reduces drag torque, reduces power loss, and improves transmission efficiency.

[0054] In this embodiment, a cavity with an opening toward the motor 1 is provided on the bridge housing 21 , and the driving gear shaft 22 , the inner friction plate 25 , the outer friction plate 24 , the service brake assembly and the parking brake assembly are all installed in the cavity of the bridge housing 21 .

[0055] In this embodiment, the cavity of the bridge housing 21 includes a side wall and an annular inner wall, and a first clamping groove is opened on the inner wall. The first clamping ring 20 is clamped at the first clamping groove. The side wall of the bridge housing 21, the parking oil cylinder body 31, the driving oil cylinder body 41 and the first clamping ring 20 are pressed tightly in sequence, and the parking oil cylinder body 31 and the driving oil cylinder body 41 are tightly matched with the inner wall of the bridge housing 21, thereby fixing the parking oil cylinder body 31 and the driving oil cylinder body 41 in the bridge housing 21.

[0056] In this embodiment, the parking brake piston 33 and the service brake piston 43 are both annular, and the driving gear shaft 22 passes through the inner sides of the outer friction plate 24, the inner friction plate 25, the parking brake piston 33, and the service brake piston 43. This arrangement allows the annular pistons to more evenly abut the friction plates, thereby achieving a more stable braking effect.

[0057] In this embodiment, both the parking oil cylinder 31 and the driving oil cylinder 41 are annular in shape. The driving gear shaft 22 passes through the inside of the parking oil cylinder 31 and the driving oil cylinder 41. The parking oil chamber 35 between the parking oil cylinder 31 and the parking brake piston 33 is annular in shape, while the service oil chamber 44 between the service oil cylinder 41 and the service brake piston 43 is also annular in shape. This arrangement makes the piston movement more uniform and stable, thereby improving the braking effect of the integrated mechanism.

[0058] In order to make the structure of the integrated mechanism more compact, in this embodiment, Figure 4 and Figure 5 As shown, a first connecting portion 32 protrudes inwardly on the parking cylinder body 31, and a first abutting portion 34 protrudes inwardly on the parking brake piston 33 toward the friction plate 25. The first abutting portion 34 is located on the inner side of the first connecting portion 32, and the first abutting portion 34 can extend from the inner side of the first connecting portion 32 and abut against the friction portion 431. The parking cylinder body 31, the first connecting portion 32, the first abutting portion 34 and the parking brake piston 33 enclose a parking oil chamber 35, and a second connecting portion 42 protrudes inwardly on the driving oil cylinder body 41 toward the friction plate 25. The second connecting portion 42 is located on the inner side of the parking brake piston 33, and a first accommodating groove is provided on the end surface of the second connecting portion 42 close to the inner friction plate 25. The first accommodating groove is a step groove. Part of the driving brake piston 43 is inserted into the first accommodating groove and matches the first accommodating groove. The stepped first accommodating groove and the driving brake piston 43 enclose a driving oil chamber 44. Such an arrangement makes the structure between the service brake assembly and the parking brake assembly more compact, further improves the utilization rate of the space in the bridge housing 21, and further improves the integration rate of the integrated mechanism.

[0059] More preferably, Figure 4 and Figure 5 As shown, the parking brake piston 33 is located between the first connecting portion 32 and the driving oil cylinder body 41, a second accommodating groove is provided on the parking brake piston 33, a third accommodating groove is provided on the driving oil cylinder body 41, the parking spring 36 is located between the second accommodating groove and the third accommodating groove, and the two ends of the parking spring 36 are respectively against the inner wall of the second accommodating groove and the inner wall of the third accommodating groove.

[0060] Further preferably, a fourth accommodating groove is defined on the service brake piston 43, and a plurality of through-holes are defined within the fourth accommodating groove. A threaded hole coaxial with the through-hole is defined within the first accommodating groove of the service oil cylinder body 41. The return bolt 45 comprises a head, an intermediate connecting portion, and a threaded portion connected in sequence. The return spring 46 of the service brake assembly is sleeved on the intermediate connecting portion. The threaded portion of the return bolt 45 passes through the through-hole and is threadedly connected to the threaded hole in the service oil cylinder body 41. A portion of the intermediate connecting portion extends into the through-hole of the service brake piston 43. The two ends of the return spring 46 respectively abut against the head of the return bolt 45 and the service brake piston 43. Further preferably, there are multiple return bolts 45, and the multiple return bolts 45 are evenly arranged around the driving gear shaft 22.

[0061] To ensure the sealing of the parking oil chamber 35 and the driving oil chamber 44, in this embodiment, a first oil seal is provided between the first connecting portion 32 and the first abutting portion 34 in the parking oil chamber 35, and a second oil seal is provided between the parking brake piston 33 and the parking oil cylinder body 31. In the driving oil chamber 44, a third oil seal is provided between the second abutting portion and the first accommodating groove, and a fourth oil seal is provided between the driving brake piston 43 and the inner wall of the first accommodating groove. Further preferably, the first, second, third, and fourth oil seals are all step seals. Further preferably, the first oil seal is fixed to the first connecting portion 32, the second oil seal is fixed to the parking oil cylinder body 31, and the third and fourth oil seals are both fixed in the accommodating groove. This arrangement ensures the sealing effect of the oil chamber and the stability of the braking force.

[0062] In order to facilitate the flow of oil into and out of the parking oil chamber 35 and the driving oil chamber 44, in this embodiment, Figure 2 、 Figure 4 and Figure 6 As shown, the parking oil cylinder body 31 is provided with a parking oil inlet 311 communicating with the parking oil chamber 35, and the bridge housing 21 is provided with a parking brake oil inlet connector 37 inserted into the parking oil inlet 311; Figure 1 and Figure 6 As shown, a driving oil inlet port 411 communicating with the driving oil chamber 44 is provided on the driving oil cylinder body 41, and a driving brake oil inlet connector 47 inserted into the driving oil inlet port 411 is installed on the bridge housing 21. Such a configuration facilitates the flow of hydraulic oil in and out and the connection of oil pipes, and the brake oil inlet connector can also prevent the parking cylinder body from rotating relative to the bridge housing 21, thereby ensuring the stability of the oil cylinder position. Further preferably, the radial direction and end face of the parking brake oil inlet connector 37 are sealed with O-rings, and the radial direction and end face of the driving brake oil inlet connector 47 are sealed with O-rings. Further preferably, as Figure 1 and Figure 6As shown, the driving oil cylinder body 41 is further provided with an exhaust port connected to the driving oil chamber 44 , the bridge housing 21 is provided with an exhaust connector seat inserted into the exhaust port, and the exhaust connector seat is provided with an exhaust connector 71 .

[0063] To further enhance the stability of the mechanism, in this embodiment, the parking cylinder 31 is secured to the axle housing 21 with axially extending screws. This arrangement constrains the parking cylinder 31 radially by the axle housing 21 and circumferentially by the parking brake oil inlet connector 37. The screws constrain the parking cylinder 31 circumferentially, thereby integrating the axle housing 21 and the parking cylinder 31 into a single unit and minimizing the risk of movement of the driving cylinder 41.

[0064] To enhance braking effectiveness, in this embodiment, a third abutment is formed on the end of the first abutment portion 34 of the parking brake piston 33, and a fourth abutment is formed on the second abutment portion of the service brake piston 43. When the parking brake piston 33 is braking, the end surfaces of the first abutment portion 34 and the third abutment contact tightly against the inner friction plate 25. When the service brake piston 43 is braking, the end surfaces of the second abutment portion and the fourth abutment contact tightly against the inner friction plate 25. This arrangement increases the contact area between the piston and the friction plate, enhancing braking effectiveness.

[0065] More preferably, the fourth abutting portion is located inside the third abutting portion, and both the third abutting portion and the fourth abutting portion are located between the inner friction plate 25 and the second connecting portion 42 of the driving oil cylinder body 41. This arrangement further improves the compactness of the integrated mechanism.

[0066] To make the integrated mechanism more compact, in this embodiment, the inner friction plate 25 is located inside the parking cylinder 31, and the inner friction plate 25 and the parking brake piston 33 are located on either side of the first connecting portion 32. This arrangement improves the connection effect of the integrated mechanism and further enhances the integration of the service brake and parking brake.

[0067] In order to improve the durability of the integrated mechanism, in this embodiment, an end plate 26 that can slide axially along the driving gear shaft 22 is installed between the inner friction plate 25 and the first connecting portion 32 of the parking cylinder body 31. The service brake piston 43 and the parking brake piston 33 push the end plate 26 to press the inner friction plate 25 and the outer friction plate 24, thereby better protecting the brake piston.

[0068] Further preferably, a plurality of guide pins 27 are fixed within the opening of the axle housing 21. The plurality of guide pins 27 are located inside the parking cylinder body 31. The plurality of guide pins 27 are evenly arranged around the driving gear shaft 22 and pass through the end plate 26 and the outer friction plate 24. This arrangement ensures that the outer friction plate 24 and the end plate 26 move along the same path, thereby improving braking stability.

[0069] More preferably, Figure 5 As shown, a separation spring 28 is sleeved on the guide pin 27, and the two ends of the separation spring 28 respectively abut against the end plate 26 and the outer friction plate 24. In this arrangement, the separation spring 28 is added between the friction plates, which reduces the drag torque, reduces the power loss, and improves the transmission efficiency.

[0070] More preferably, Figure 5 As shown, a fifth receiving groove is defined in the sidewall of the cavity of the axle housing 21, and a sixth receiving groove is defined in the first connecting portion 32 of the parking cylinder 31. The ends of the guide pin 27 are respectively located in the fifth and sixth receiving grooves, where they fit tightly together. This arrangement, through the guide pin 27, allows for more precise positioning between the parking cylinder 31 and the axle housing 21, while also facilitating assembly of the integrated mechanism.

[0071] In this embodiment, Figure 4 As shown, a brake hub 23 is sleeved and fixedly mounted on the driving gear shaft 22. An inner friction plate 25, an outer friction plate 24, and an end plate 26 are all sleeved on the brake hub 23. The inner friction plate 25 and the brake hub 23 are spline-connected. The brake hub 23 is connected to the driving gear shaft 22 in the following manner: a raised step is formed on the driving gear shaft 22. A second retaining ring 201, a first bearing 29, and the brake hub 23 are sequentially sleeved on the driving gear shaft 22. The second retaining ring 201 is engaged with the driving gear shaft 22. The brake hub 23 is spline-connected to the driving gear shaft 22. The second retaining ring 201, the first bearing 29, the brake hub 23, and the step on the driving gear shaft 22 are sequentially abutted. The second retaining ring 201 and a portion of the brake hub 23 can extend into the opening of the service brake piston 43. This arrangement prevents the friction plates from operating directly on the driving gear shaft 22, thereby preventing damage to the driving gear shaft 22. It also effectively utilizes the space within the motor housing 1 and makes the integrated mechanism more compact.

[0072] During the vehicle's travel: the parking oil chamber is filled with oil, the driving oil chamber is not filled with oil, the parking brake piston is away from the friction part of the driving brake piston, the parking brake piston moves and compresses the parking spring, the return spring pushes the driving brake piston away from the friction plate, the release spring pushes the outer friction plate, the inner friction plate and the end plate to separate from each other, and the driving gear shaft 22 is in a free rotation state;

[0073] When the vehicle brakes while driving, the service oil chamber is filled with oil, and the hydraulic oil pushes the service brake piston to move. The service brake piston moves and compresses the return spring. The friction part of the service brake piston moves to press the outer friction plate, inner friction plate and end plate together. The movement of the end plate compresses the release spring. The end plate, inner friction plate and outer friction plate squeeze each other and gradually reduce the speed of the driving gear shaft 22, completing the braking process of the vehicle while driving.

[0074] When the vehicle is parked, the parking oil chamber drains oil, the driving oil chamber drains oil, the parking spring pushes the parking brake piston to move, the parking brake piston drives the driving brake piston to move, the friction part of the driving brake piston moves to press the outer friction plate, inner friction plate and end plate, and the movement of the end plate compresses the separation spring; thus completing the parking action.

[0075] 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.

[0076] 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. An electric drive axle assembly with integrated wet parking brake and service brake, comprising a motor (1), a bridge housing (21), a differential (5) and a wheel hub unit assembly (6); two bridge housings (21) are respectively fixed on both sides of the motor (1), and the wheel hub unit assembly (6) is respectively installed on the two bridge housings (21); the differential (5) is installed in one bridge housing (21), the differential (5) is connected to the motor (1), and the differential (5) transmits the power of the motor (1) to the driving gear shafts (22) rotatably installed in the two bridge housings (21), and the power of the driving gear shaft (22) is output through the wheel hub unit assembly (6); a service brake assembly and a parking brake assembly for implementing braking of the driving gear shaft (22) are also installed in the bridge housing (21); it is characterized in that: The driving gear shaft (22) is provided with inner friction plates (25) and outer friction plates (24) that are alternately arranged, the inner friction plates (25) are slidably connected to the driving gear shaft (22), and the outer friction plates (24) are slidably connected to the axle housing (21); The service brake assembly includes a service brake piston (43) slidably mounted in the bridge housing (21), and the parking brake assembly includes a parking brake piston (33) slidably mounted in the bridge housing (21). The service brake piston (43) has a friction portion (431) protruding from one end thereof toward the friction plate, and the friction portion (431) is located between the parking brake piston (33) and the friction plate. When the service brake piston (43) moves, it can drive the inner friction plate (25) and the outer friction plate (24) to combine and implement braking through the friction portion (431); When the parking brake piston (33) moves, it can drive the inner friction plate (25) and the outer friction plate (24) to combine and implement braking through the friction portion (431).

2. The electric drive axle assembly integrating wet parking brake and service brake according to claim 1, characterized in that: The service brake piston (43) is located inside the parking brake piston (33).

3. The electric drive axle assembly integrating wet parking brake and service brake according to claim 1, characterized in that: The service brake assembly further includes a service oil cylinder (41) and a return spring (46) for driving the service brake piston (43) to return to its original position; The driving oil cylinder body (41) is fixed on the bridge housing (21), the driving brake piston (43) is slidably mounted on the driving oil cylinder body (41), and a driving oil chamber (44) is provided between the driving brake piston (43) and the driving oil cylinder body (41).

4. The electric drive axle assembly integrating wet parking brake and service brake according to claim 3, characterized in that: A second connecting portion (42) protrudes from the driving oil cylinder body (41) toward the inner friction plate (25). The second connecting portion (42) is located inside the parking brake piston (33). A first accommodating groove is provided on the end surface of the second connecting portion (42) close to the inner friction plate (25). The first accommodating groove is a step groove. A portion of the driving brake piston (43) is inserted into the first accommodating groove and matches the first accommodating groove. The stepped first accommodating groove and the driving brake piston (43) enclose a driving oil chamber (44).

5. The electric drive axle assembly integrating wet parking brake and service brake according to claim 4, characterized in that: A fourth accommodating groove is provided on the service brake piston (43), and a plurality of through holes are provided in the fourth accommodating groove. A threaded hole coaxial with the through hole is provided in the first accommodating groove of the service oil cylinder body (41); the return bolt (45) comprises a head, an intermediate connecting portion and a threaded portion connected in sequence, and the return spring (46) of the service brake assembly is sleeved on the intermediate connecting portion. The threaded portion of the return bolt (45) passes through the through hole and is threadedly connected to the threaded hole on the service oil cylinder body (41), and part of the intermediate connecting portion extends into the through hole of the service brake piston (43). The two ends of the return spring (46) respectively abut against the head of the return bolt (45) and the service brake piston (43).

6. The electric drive axle assembly integrating wet parking brake and service brake according to claim 5, characterized in that: In the service oil chamber (44), a third oil seal is provided between the second abutting portion and the first accommodating groove, and a fourth oil seal is provided between the service brake piston (43) and the inner wall of the first accommodating groove.

7. The electric drive axle assembly integrating wet parking brake and service brake according to claim 1, characterized in that: The parking brake assembly includes a parking brake piston (33), a parking oil cylinder (31), and a parking spring (36) for driving the parking brake piston (33) to return to its original position. The parking oil cylinder body (31) is fixed on the bridge housing (21), the parking brake piston (33) is slidably mounted on the parking oil cylinder body (31), a parking oil chamber (35) is provided between the parking brake piston (33) and the parking oil cylinder body (31), and the friction portion (431) is located between the service brake piston (43) and the friction plate.

8. The electric drive axle assembly integrating wet parking brake and service brake according to claim 7, characterized in that: A first connecting portion (32) protrudes inwardly from the parking oil cylinder body (31), and a first abutting portion (34) protrudes inwardly from the friction plate (25) on the parking brake piston (33). The first abutting portion (34) is located inside the first connecting portion (32), and the first abutting portion (34) can extend from the inside of the first connecting portion (32) and abut against the friction portion (431). The parking oil cylinder body (31), the first connecting portion (32), the first abutting portion (34) and the parking brake piston (33) enclose a parking oil chamber (35).

9. The electric drive axle assembly integrating wet parking brake and service brake according to claim 8, characterized in that: The parking brake piston (33) is located between the first connecting portion (32) and the driving oil cylinder body (41), a second accommodating groove is provided on the parking brake piston (33), a third accommodating groove is provided on the driving oil cylinder body (41), a parking spring (36) is located between the second accommodating groove and the third accommodating groove, and two ends of the parking spring (36) are respectively against the inner wall of the second accommodating groove and the inner wall of the third accommodating groove.

10. The electric drive axle assembly integrating wet parking brake and service brake according to claim 9, characterized in that: In the parking oil chamber (35), a first oil seal is provided between the first connecting portion (32) and the first abutting portion (34), and a second oil seal is provided between the parking brake piston (33) and the parking oil cylinder body (31).

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