A drive axle and its service brake assembly

Abstract

The application discloses a drive axle and a driving brake assembly thereof, which comprises a first shaft sleeve, an annular piston, a plurality of annular first outer friction plates and a plurality of annular first inner friction plates in a second shell, the first shaft sleeve is in transmission cooperation with a half shaft through internal splines, the plurality of annular first inner friction plates and the first outer friction plates are alternately stacked with each other, the piston is installed on the second shell and can move between a braking position and a non-braking position, an elastic check ring is further arranged, an axial spline groove and a circumferential annular groove are arranged on the outer surface of the first shaft sleeve, a plurality of first installation grooves are arranged on the inner side wall of the second shell, the first outer friction plate is clamped in the first installation groove, the first inner friction plate is clamped in the spline groove and is further in transmission connection with the first shaft sleeve, and the elastic check ring is clamped in the annular groove and is located between any two adjacent first inner friction plates.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automotive technology, in particular to a drive axle and a service brake assembly thereof. BACKGROUND

[0002] It is known that the working conditions of engineering machinery are relatively harsh, at present, the domestic engineering machinery axle product market is still dominated by dry-type brake drive axle, and the dry-type drive axle adopts external dry-type brake, which causes the dry-type drive axle to be greatly affected by environmental factors such as dampness, freezing and sand, and the braking performance is unstable, and the service life is short; the wet-type brake is internal, and is basically not affected by environmental factors, has a long service life, safe and reliable braking, and has been widely used in existing engineering machinery.

[0003] And in the prior art, the drive axle has been applied to the forklift truck, such as the Chinese patent document CN107265354A discloses a forklift truck service and parking integrated drive axle, which comprises an input assembly, an axle housing, a first half shaft, a second half shaft, a spline sleeve and a fixed gear ring, and a first brake assembly and a second brake assembly located in the axle housing. The patent effectively solves the problems of poor braking stability and inconvenient maintenance caused by the original dry-type brake. In the patent document, the friction plate and the spacer can be maintained and replaced without disassembling the axle housing, but it is inevitable that the friction plate will be thinned due to wear during use, thereby reducing the braking force. In order to ensure the safety of driving, the friction plate will not have any use value when it is worn to a certain extent, thereby causing high maintenance cost and low service life of the friction plate.

[0004] In addition, the power of the existing drive axle is often provided by the transmission, so the vibration from the hub on the drive axle is easily transmitted to the transmission, and when the transmission case is subjected to the vibration, the vibration of the automobile and different degrees of noise are caused, and the vibration of the transmission case also easily causes damage to the internal parts of the transmission;

[0005] Therefore, the Chinese patent document with the publication number CN110043585A discloses a drive axle, which comprises an axle housing, an input assembly, a first brake assembly, a first half shaft, a first wheel hub assembly, a second half shaft, a second brake assembly and a second wheel hub assembly, the second brake assembly has the same structure as the brake assembly, the input assembly is mounted on the axle housing, the first brake assembly is located at the left end of the axle housing, the right section of the first half shaft is connected with the input assembly, the first half shaft passes through the first brake assembly, the second brake assembly is located at the right end of the axle housing, the left section of the second half shaft is connected with the input assembly, and the second half shaft passes through the second brake assembly; the first brake assembly and the second brake assembly can compensate for the wear of the friction plate, so as to prolong the service life of the friction plate, and the input assembly can be provided with a buffering mechanism, so that the influence of the vibration of the drive axle on the transmission can be effectively reduced, and the service life of the drive axle can be prolonged.

[0006] However, the above-mentioned drive axle has the following disadvantages found by the person skilled in the art during use:

[0007] 1) the input shaft and the output shaft in the input assembly are arranged vertically, so that the drive axle occupies a large space;

[0008] 2) the friction plate in the service brake assembly is directly mounted on the half shaft, so that the installation of the friction plate is facilitated, but the installation of the half shaft is difficult, and the opening of the housing is large, so that the structure of the wheel hub assembly is complex, and the transmission relationship between the half shaft and the wheel hub assembly is also complex;

[0009] 3) the transmission level between the parking brake handle and the brake friction plate in the parking brake assembly is at least two levels, and the torque is small. SUMMARY

[0010] The purpose of the present application is to solve the above-mentioned problems of the service brake assembly, and provide a drive axle and a service brake assembly thereof, which realizes the axial positioning of the first shaft sleeve through the cooperation of the inner and outer friction plates and the elastic retainer, and has a simple structure and is convenient to install.

[0011] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0012] A service brake assembly of a drive axle, comprising a first shaft sleeve located in a second housing, an annular piston, a plurality of annular first outer friction plates and a plurality of annular first inner friction plates, the first shaft sleeve is in transmission cooperation with the half shaft through internal splines, the first outer friction plate is in axial movable cooperation with the second housing in the circumferential direction, the first inner friction plate is in axial movable cooperation with the first shaft sleeve in the circumferential direction, the plurality of annular first inner friction plates and the first outer friction plates are alternately stacked with each other, and the piston is installed on the second housing and can move between a braking position and a non-braking position; characterized in that,

[0013] The elastic check ring is arranged on the outer surface of the first shaft sleeve, and the first outer friction plate is arranged in the first installation slot.

[0014] Preferably, the thickness of the elastic check ring is less than the thickness of the first outer friction plate.

[0015] Preferably, a plurality of first pins and a plurality of first springs sleeved on the first pins are arranged, the first outer friction plate is provided with a plurality of first through holes, one end of the first pin passes through the first through hole of the first outer friction plate and abuts against the second housing, the other end of the first pin abuts against the second shaft sleeve, the first springs are sequentially arranged between the adjacent two first outer friction plates, and the two ends of the first spring abut against the adjacent two first outer friction plates, so that the adjacent two first outer friction plates are expanded by the first spring.

[0016] Preferably, the return spring seat, the return spring and the return spring screw are arranged in the second housing, the return spring moves the annular piston from the braking position to the non-braking position, the second installation hole is uniformly distributed on the side surface of the piston, the return spring seat is installed in the second installation hole in an interference fit, the return spring screw passes through the return spring seat and is installed on the second housing, the return spring is sleeved on the return spring screw, one end of the return spring abuts against the return spring seat, and the other end of the return spring abuts against the return spring screw.

[0017] Preferably, the return spring screw limits the stroke of the return spring seat to the first gap, the annular piston and the return spring seat are movably connected in an interference fit, when the inner friction plate and the outer friction plate are in an unworn state, the displacement stroke between the braking position and the non-braking position of the annular piston is not greater than the first gap, when the inner friction plate and the outer friction plate are worn, the annular piston and the return spring seat are fixed in an interference fit after relative displacement, the return spring screw limits the stroke of the return spring seat to the first gap, so that the displacement stroke between the braking position and the non-braking position of the annular piston is the first gap.

[0018] Preferably, the return spring screw is provided with a first flange, the center hole of the return spring seat is a stepped hole, one end of the return spring abuts against the first flange of the return spring screw, and the other end of the return spring abuts against the stepped hole of the center hole of the return spring seat.

[0019] Preferably, the distance between the first flange and the return spring seat is the first gap, when the annular piston moves from the non-braking position to the braking position, the first flange can abut against the return spring seat, so as to limit the stroke of the return spring seat to the first gap.

[0020] As preferred, the drive axle further comprises a hub assembly, the hub assembly comprising a second shaft sleeve and a hub piece, the second shaft sleeve being sleeved on the half shaft and fixedly connected with the outer end of the second housing, and the hub piece being fixedly connected with the half shaft.

[0021] When the piston moves to the braking position, the plurality of first inner friction plates and the first outer friction plate are pressed against and on the second shaft sleeve.

[0022] As preferred, the second shaft sleeve comprises an integral shaft sleeve part and a flange part, the flange part being fixedly installed on the outer end face of the second housing by a plurality of fasteners, the other end of the first latch abutting against the inner end face of the flange part, and when the piston moves to the braking position, the plurality of first inner friction plates and the first outer friction plate are pressed against the inner end face of the flange part.

[0023] A drive axle comprising the service brake assembly of the drive axle as described above.

[0024] The present application has the following beneficial effects:

[0025] 1) The service brake assembly of the drive axle is optimized by the technical solution: the first inner friction plate is installed on the half shaft through the first shaft sleeve, which simplifies the shape of the half shaft, facilitates the installation of the half shaft, and makes the structure of the hub assembly simple.

[0026] In addition, the axial positioning of the first shaft sleeve can be completed through the cooperation of the first outer friction plate, the first inner friction plate, the elastic retainer and the first shaft sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the transmission structure of the drive axle of the present application;

[0028] Figure 2 is a schematic diagram of the transmission structure of the input assembly of the present application;

[0029] Figure 3 is a schematic diagram of the transmission structure of the service brake assembly of the present application;

[0030] Figure 4 is a schematic diagram of the transmission structure of the parking brake assembly of the present application;

[0031] Figure 5 is a sectional view of the parking brake mounting seat of the present application;

[0032] Figure 6 is a sectional view of the torsion spring seat of the present application;

[0033] Figure 7 is a sectional view of the rotating shaft of the present application;

[0034] Figure 8 is a sectional view of the second shaft sleeve of the present application;

[0035] Figure 9 is a sectional view of the present application's pressure plate.

[0036] BRIEF DESCRIPTION OF DRAWINGS 2, input assembly; 3, service brake assembly; 4, hub assembly; 101, first housing; 102, second housing; 103, half shaft; 202, differential housing; 203, first planetary gear; 204, half shaft gear; 206, input shaft; 207, intermediate shaft; 208, first gear; 209, second gear; 210, motor; 301, first shaft sleeve; 302, piston; 303, first outer friction plate; 304, first inner friction plate; 401, second shaft sleeve; 402, hub piece; 403, first tapered roller bearing; 404, first oil seal; 405, second oil seal; 4013, first blocking portion; 4014, second blocking portion; 305, elastic retainer; 306, first latch; 307, first spring; 4011, shaft sleeve portion; 4012, flange portion; 308, return spring seat; 309, return spring; 310, return spring screw; 311, first seal; 312, second seal; 3101, first flange; 211, parking brake mounting seat; 212, pull rod; 213, rotating shaft; 214, pressure plate; 215, second inner friction plate; 216, second outer friction plate; 217, pin shaft; 218, second spring; 2131, cam portion; 2141, sliding portion; 219, torsion spring seat; 220, first torsion spring; 221, second latch; 222, third seal; 223, fourth seal; 2111, fourth through hole; 2132, second flange; 2191, V-shaped groove; 2112, first mounting hole; 2113, third through hole; 2114, cavity; 2115, second positioning hole. DETAILED DESCRIPTION

[0037] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or components referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0039] Furthermore, the terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eight" are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of indicated features. Thus, a feature defined with "first", "second", "third", "fourth", "fifth", "sixth", "seventh" or "eight" can include one or more of the features, either explicitly or implicitly. In the description of the application, the meaning of "a plurality of" is two or more, unless explicitly stated otherwise.

[0040] In the present application, unless specifically stated and limited otherwise, the terms "mounting", "connected", "coupled", "fixed", and the like, should not be construed as being limited to direct and immediate connections only, but can be construed as being inclusive of indirect connections, removable couplings, or integrally connected couplings, and can be either mechanical or electrical connections, or direct or indirect connections through intervening media, or internal connections of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0041] In the present application, unless specifically stated and limited otherwise, "above" or "below" of a first feature with respect to a second feature can include direct contact between the first and second features, or indirect contact between the first and second features through another feature therebetween. Furthermore, "above", "over" and "on" of a first feature with respect to a second feature includes the first feature being directly above and obliquely above the second feature, or only indicating that the first feature is higher in horizontal height than the second feature. "Below", "under" and "underneath" of a first feature with respect to a second feature includes the first feature being directly below and obliquely below the second feature, or only indicating that the first feature is lower in horizontal height than the second feature.

[0042] In the present application, the direction from the hub assembly to the differential assembly is "inward", and the direction from the differential assembly to the hub assembly is "outward".

[0043] In the present application, "transverse" and "vertical" are both based on the orientation in Figure 1 .

[0044] A drive axle, as shown in Figure 1 , comprises an axle housing, an input assembly 2, two road brake assemblies 3, two coaxially distributed half shafts 103 and two hub assemblies 4, the axle housing comprises a first housing 101 and two second housings 102 fixedly connected, the two second housings 102 are respectively located on the left and right sides of the first housing 101, the road brake assembly 3 is located in the second housing 102 and is sleeved on the half shaft 103, the hub assembly 4 is installed at the outer end of the second housing 102 and is fixedly connected with the outer end of the half shaft 103, and the input assembly 2 is installed on the first housing 101.

[0045] As shown in Figure 2As shown, the input assembly 2 comprises a differential assembly, which comprises a differential housing 202, a first planetary gear 203 and two axle gears 204, the differential housing 202 is mounted on the inner side of the first housing 101 and can rotate in the first housing 101, the first planetary gear 203 is mounted on the inner side of the differential housing 202 and can rotate with the differential housing 202, the two axle gears 204 are respectively located on the left and right sides of the inner side of the differential housing 202, and the two axle gears 204 are in mesh with the first planetary gear 203, and the inner end of the axle shaft 103 extends into the differential housing 202 and is in driving connection with the axle gear 204.

[0046] In the embodiment, the input assembly 2 further comprises an input shaft 206, an intermediate shaft 207, a first gear 208 and a second gear 209 mounted on the first housing 101, the input shaft 206 is in driving connection with the motor 210, the first gear 208 is sleeved on the intermediate shaft 207 and is in driving connection with the intermediate shaft 207, the first gear 208 is in driving engagement with the shaft teeth of the input shaft 206, the second gear 209 is in driving engagement with the shaft teeth of the intermediate shaft 207, the second gear 209 is fixedly connected with the differential housing 202, and the input shaft 206, the intermediate shaft 207 and the two axle shafts 103 are transversely distributed.

[0047] As shown in the figure, Figure 3 The service brake assembly 3 comprises a first shaft sleeve 301, an annular piston 302, a plurality of annular first outer friction plates 303 and a plurality of annular first inner friction plates 304, the first shaft sleeve 301 is in driving engagement with the axle shaft 103 through internal splines, the first outer friction plate 303 is in axial movable engagement with the first housing 101 in the circumferential direction, the first inner friction plate 304 is in axial movable engagement with the first shaft sleeve 301 in the circumferential direction, the plurality of annular first inner friction plates 304 and the first outer friction plates 303 are alternately stacked with each other, and the piston 302 is mounted on the second housing 102 and can move between a braking position and a non-braking position.

[0048] The hub assembly 4 comprises a second shaft sleeve 401 and a hub 402, the second shaft sleeve 401 is sleeved on the axle shaft 103 and is fixedly connected with the outer end of the second housing 102, and the hub 402 is fixedly connected with the axle shaft 103.

[0049] When the service brake assembly 3 is in the braking state, the piston 302 moves to the braking position so that the plurality of first inner friction plates 304 and the first outer friction plates 303 abut and press on the second shaft sleeve 401.

[0050] The input shaft 206 and the output shaft are arranged transversely, which effectively improves the transmission structure in the drive axle, and thus makes the drive axle housing structure reasonable and the volume reduced, and thus the space occupied by the drive axle is reduced; in addition, one pressure plate is saved, and the structure of the parts of the drive axle is more compact, and the cost is saved.

[0051] In the embodiment, two first tapered roller bearings 403 are further arranged, the first tapered roller bearings are sleeved on the second shaft sleeve 401, and the outer surfaces of the tapered roller bearings are in abutment with the inner surface of the hub 402; preferably, the second shaft sleeve 401 is provided with a first blocking portion 4013 and a second blocking portion 4014 for preventing the tapered roller bearings from moving axially, wherein the first blocking portion 4013 is formed by a protrusion on the second shaft sleeve 401, and the second blocking portion 4014 is detachably coupled with the second shaft sleeve 401, and the arrangement is to facilitate the installation of the two first tapered roller bearings 403.

[0052] In the embodiment, a first oil seal 404 and a second oil seal 405 are further arranged, the first oil seal 404 is located between the second shaft sleeve 401 and the hub 402, and the second oil seal 405 is located between the half shaft 103 and the second shaft sleeve 401.

[0053] In the embodiment, an elastic retaining ring 305 is further arranged, the outer surface of the first shaft sleeve 301 is provided with an axial spline groove and a circumferential annular groove, the inner side wall of the second housing 102 is provided with a plurality of first installation grooves, and the first outer friction plate 303 is clamped in the first installation grooves; the first inner friction plate 304 is clamped in the spline groove and is in driving connection with the first shaft sleeve 301, and the elastic retaining ring 305 is clamped in the annular groove and is located between any two adjacent first inner friction plates 304; the arrangement achieves the axial positioning of the first shaft sleeve 301 through the cooperation of the first outer friction plate 303 and the first installation groove, the cooperation of the first inner friction plate 304 and the first outer friction plate 303, and the cooperation of the first inner friction plate 304 and the elastic retaining ring 305.

[0054] Further preferably, the thickness of the elastic retaining ring 305 is less than the thickness of the first outer friction plate 303.

[0055] In the embodiment, a plurality of first pins 306 are circumferentially and uniformly distributed, and a plurality of first springs 307 are sleeved on the first pins 306. The first outer friction plates 303 are provided with a plurality of first through holes which are circumferentially and uniformly distributed. One end of the first pin 306 penetrates the first through hole on the first outer friction plate 303 and abuts against the second housing 102. The other end of the first pin 306 abuts against the second shaft sleeve 401. The first springs 307 are sequentially distributed between two adjacent first outer friction plates 303, and the two ends of the first spring 307 abut against the two adjacent first outer friction plates 303, so that the two adjacent first outer friction plates 303 are separated by the first spring 307. Such an arrangement makes the two first outer friction plates 303 more thoroughly spread apart, avoiding the generation of friction or large friction between the first inner friction plate 304 and the first outer friction plate 303 in the non-braking state.

[0056] In the embodiment, as shown in Figure 8 The second shaft sleeve 401 includes an integrally formed shaft sleeve part 4011 and a flange part 4012. The flange part 4012 is fixedly installed on the outer end face of the second housing 102 by a plurality of fasteners. The other end of the first pin 306 abuts against the inner end face of the flange part 4012. When the piston 302 moves to the braking position, the plurality of first inner friction plates 304 and the first outer friction plates 303 are pressed against the inner end face of the flange part 4012.

[0057] In the embodiment, the service brake assembly 3 further includes a return spring seat 308, a return spring 309 and a return spring screw 310 in the second housing 102. The return spring 309 moves the annular piston 302 from the braking position to the non-braking position. The piston 302 is uniformly provided with a plurality of second mounting holes on the side face. The return spring seat 308 is interference-fitted and installed in the second mounting hole. The return spring screw 310 penetrates the return spring seat 308 and is installed on the second housing 102. The return spring 309 is sleeved on the return spring screw 310. One end of the return spring 309 abuts against the return spring seat 308, and the other end abuts against the return spring screw 310.

[0058] The outer surface of the return spring seat 308 is a cylindrical surface and is in interference fit with the second mounting hole. It is worth noting that the outer surface of the return spring seat 308 can also be other shapes, such as triangular prism, cuboid, etc., and the corresponding second mounting hole is in interference fit with the outer surface of the return spring seat 308. The specific form is that the return spring seat 308 and the annular piston 302 can drive each other to move. When there is wear on the first inner friction plate 304 and the first outer friction plate 303, the travel of the return spring seat 308 is limited to the first gap by the return spring screw 310, and the annular piston 302 and the first outer friction plate 303 still have a gap, and the annular piston 302 can still move axially under the action of oil pressure until the end face abuts against the first outer friction plate 303.

[0059] Specifically, the end face of the annular piston 302 on the outer side can abut against the first outer friction plate 303, and the end face of the annular piston 302 on the inner side can abut against the first housing 101. The first annular groove and the second annular groove are arranged on the circumferential side wall of the annular piston 302, and the first sealing ring 311 and the second sealing ring 312 are respectively arranged in the first annular groove and the second annular groove.

[0060] Specifically, the return spring screw 310 is provided with a first flange 3101, one end of the return spring 309 abuts against the first flange 3101, and the other end abuts against the return spring seat 308. The distance between the first flange 3101 and the return spring seat 308 is the first gap. When the annular piston 302 moves from the non-braking position to the braking position abutting against the first outer friction plate 303, the first flange 3101 can abut against the return spring seat 308, thereby limiting the travel of the return spring seat 308 to the first gap. In this embodiment, the first flange 3101 can be disc-shaped or other shapes. As long as the first flange 3101 can abut against the return spring seat 308 when the annular piston 302 moves from the non-braking position to the braking position abutting against the first outer friction plate 303, it is acceptable. In this embodiment, the first flange 3101 is preferably disc-shaped, and the diameter of the disc is greater than the inner diameter of the spring seat, so that the first flange 3101 can abut against the return spring seat 308.

[0061] When the friction plate is not worn and is in a non-braking state, the inner end face of the annular piston 302 abuts against a mounting face in the second housing 102. In this embodiment, the name of the mounting face in the second housing 102 is called the first mounting face for the convenience of confirmation. The return spring seat 308 is in interference fit with the second mounting hole in the annular piston 302, and one end of the return spring seat 308 abuts against the first mounting face. In this state, the distance between the first flange 3101 on the return spring screw 310 and the return spring seat 308 is the first gap.

[0062] When the pressure oil in the oil chamber is released, the return spring seat 308 moves away from the first inner friction plate 304 and the first outer friction plate 303 under the action of the return spring 309, and drives the annular piston 302 to move to the non-braking state. In this process, the displacement of the return spring seat 308 and the annular piston 302 is the first gap, so there is a third gap between the inner end face of the annular piston 302 and the first mounting surface, and the sum of the third gap and the first gap is the second gap. The inner end face of the return spring seat 308 protrudes from the inner end face of the annular piston 302, and the inner end face of the return spring seat 308 is still abutted against the first mounting surface. In this state, the distance between the first flange 3101 on the return spring screw 310 and the return spring seat 308 is the first gap.

[0063] When the first inner friction plate 304 and the first outer friction plate 303 are worn, the return spring screw 310 limits the stroke of the return spring seat 308 to the first gap, and the annular piston 302 can still move axially until the end face abuts against the first outer friction plate 303. When the annular piston 302 reaches the braking position abutting against the first outer friction plate 303, the inner end face of the annular piston 302 is no longer flush with the inner end face of the return spring seat 308, and the inner end face of the return spring seat 308 protrudes inwardly relative to the inner end face of the annular piston 302 by a portion, and the outer end face of the return spring seat 308 is abutted against the first flange 3101 on the return spring screw 310. In this state, the distance between the return spring seat 308 and the first mounting surface is the first gap, and the distance between the inner end face of the annular piston 302 and the first mounting surface is the second gap, which is greater than the first gap.

[0064] When the pressure oil in the oil chamber is released, the return spring seat 308 moves away from the first inner friction plate 304 and the first outer friction plate 303 under the action of the return spring 309, and drives the annular piston 302 to move to the non-braking state. In this process, the displacement of the return spring seat 308 and the annular piston 302 is the first gap, so there is a third gap between the inner end face of the annular piston 302 and the first mounting surface, and the sum of the third gap and the first gap is the second gap. The inner end face of the return spring seat 308 protrudes from the inner end face of the annular piston 302, and the inner end face of the return spring seat 308 is still abutted against the first mounting surface. In this state, the distance between the first flange 3101 on the return spring screw 310 and the return spring seat 308 is the first gap.

[0065] It is worth mentioning that in the process of the annular piston 302 from the braking point of abutting against the first outer friction plate 303 to the non-braking position of separating from the first outer friction plate 303, no matter whether the first inner friction plate 304 and the first outer friction plate 303 are in the wear condition or not, the return spring seat 308 drives the annular piston 302 to jointly move away from the first inner friction plate 304 and the first outer friction plate 303, and the moving distance is always the first gap under the limiting of the first flange 3101 and the first mounting surface, that is, the return distance of the annular piston 302 is always the first gap, that is, when the annular piston 302 reaches the braking position of abutting against the first outer friction plate 303 from the non-braking position of separating from the first outer friction plate 303 next time, the displacement required by the annular piston 302 is always the first gap, so that the purpose of compensating the wear of the first inner friction plate 304 and the first outer friction plate 303 is achieved, so that the braking distance of the brake assembly is always kept unchanged in the use process, the braking effect is ensured, and the first inner friction plate 304 and the first outer friction plate 303 are more durable, and the maintenance cost of the first inner friction plate 304 and the first outer friction plate 303 is reduced.

[0066] In addition, as the wear degree of the first inner friction plate 304 and the first outer friction plate 303 increases, the braking position of the annular piston 302 is also constantly moved outward, that is, the displacement distance of the first inner friction plate 304 and the first outer friction plate 303 is constantly increased under the condition of ensuring the braking effect, but the elasticity between the first inner friction plate 304 and the first outer friction plate 303 decreases with the increase of the wear degree of the friction plate, so that it is necessary to add springs between the friction plates to ensure that the friction plates can still return to the initial position after braking, so as to avoid the incomplete expansion of the first inner friction plate 304 and the first outer friction plate 303 in the non-braking state, thereby causing the sluggish feeling in the driving process.

[0067] In the embodiment, the input assembly 2 further comprises a first inner friction plate 304 and a first outer friction plate 303 arranged on the first mounting surface 301. Figure 4The parking brake assembly shown, the parking brake assembly includes parking brake mounting seat 211, pull rod 212, shaft 213, pressure plate 214, a number of annular second inner friction plate 215 and a number of annular second outer friction plate 216, parking brake mounting seat 211 and first shell 101 fixedly connected and jointly form a cavity 2114, the pressure plate 214 is installed on the parking brake mounting seat 211 smoothly, a number of second outer friction plate 216 is installed in the cavity 2114 and is circumferentially positioned axial movable cooperation, a number of second inner friction plate 215 is circumferentially positioned axial movable cooperation with a transmission shaft in input assembly 2 through the spline, a number of second inner friction plate 215 and second outer friction plate 216 are alternately stacked with each other, the pull rod 212 is transmission coupled or fixedly connected with the shaft 213, the shaft 213 is rotatably installed on the parking brake mounting seat 211 and pushes the pressure plate 214 to move in the process of rotating, so as to press the second inner friction plate 215 and the second outer friction plate 216 on the first shell 101, thereby making the transmission shaft in the drive axle transmission coupled with the second inner friction plate 215 unable to rotate, that is, the parking brake is completed.

[0068] In the embodiment, as shown, the parking brake mounting seat 211 is provided with a vertical first mounting hole 2112, and a transverse third through hole 2113 is arranged on the side wall of the first mounting hole 2112 close to the first shell 101, and the shaft 213 is rotatably installed in the first through hole, and the pressure plate 214 is transversely installed in the third through hole 2113. Figure 5

[0069] In the embodiment, a number of second inner friction plates 215 are circumferentially positioned and axially movably connected with the input shaft 206 through the spline; in other embodiments, a number of second inner friction plates 215 are circumferentially positioned and axially movably connected with the intermediate shaft 207 through the spline.

[0070] In the embodiment, a number of circumferentially uniformly distributed pin shafts 217 and a number of second springs 218 sleeved on the pin shafts 217 are further provided, a number of second through holes are circumferentially uniformly distributed on the second outer friction plate 216, the pin shaft 217 passes through the second through hole on the second outer friction plate 216, a number of second springs 218 are sequentially distributed between adjacent two second outer friction plates 216, and the two ends of the second spring 218 respectively abut against the adjacent two second outer friction plates 216, so that the adjacent two second outer friction plates 216 are expanded by the second spring 218 and the outer friction plate on one side abuts against the pressure plate 214. Such arrangement is because when the braking is completed, the shaft 213 cannot bring the pressure plate 214 back to the initial position, therefore, the pressure plate 214 is pushed back to the initial position by the action of the second spring 218, thereby releasing the braking state.

[0071] ​Further preferably, the first shell 101 is provided with a plurality of first positioning holes distributed uniformly in a circle, the parking brake mounting base 211 is provided with a plurality of second positioning holes 2115 distributed uniformly in a circle, and one end of the pin shaft 217 passes through the plurality of second outer friction plates 216 and is inserted into the first positioning holes, and the other end of the pin shaft 217 is inserted into the second positioning holes 2115.

[0072] In the embodiment, as shown in Figure 7 the rotating shaft 213 is provided with a cam portion 2131, and during rotation of the rotating shaft 213, the cam portion 2131 cooperates with the pressure plate 214 to enable the pressure plate 214 to press the second inner friction plate 215 and the second outer friction plate 216 against the first shell 101.

[0073] Further preferably, the cam portion 2131 is formed by a groove on the side wall of the rotating shaft 213, and the distance between the bottom surface in the groove and the side wall of the rotating shaft 213 gradually decreases, as shown in Figure 9 the end surface of the pressure plate 214 close to the rotating shaft 213 is provided with a sliding portion 2141, and the sliding portion 2141 is clamped in the groove.

[0074] It is worth noting that the cooperation of the cam portion 2131 and the sliding portion 2141 not only enables the pressure plate 214 to move, but also limits the two degrees of freedom of the rotating shaft 213 in the vertical direction, that is, the rotating shaft 213 is stably mounted on the parking brake mounting base 211 through the cooperation of the cam portion 2131 and the sliding portion 2141.

[0075] In the embodiment, a torsional spring seat 219 and a first torsional spring 220 are also provided, as shown in Figure 6 the torsional spring seat 219 is mounted in the first mounting hole 2112 and is drivingly coupled with the rotating shaft 213, the torsional spring seat 219 is located below the pull rod 212, and the first torsional spring 220 is sleeved on the outer surface of the parking brake mounting base 211 and is connected with the torsional spring seat 219. In this way, after rotation, the rotating shaft 213 can automatically return to the initial position under the action of the first torsional spring 220.

[0076] Further preferably, at least one second plug pin 221 is also provided, the rotating shaft 213 is provided with a second flange 2132, the side wall of the torsional spring seat 219 is provided with a ring of V-shaped grooves 2191, the side wall of the first mounting hole 2112 is provided with at least one fourth through hole 2111, the bottom end of the first through hole torsional spring seat 219 abuts against the second flange 2132, and the second plug pin 221 passes through the fourth through hole 2111 and abuts against the V-shaped groove 2191; in this way, the torsional spring seat 219 is mounted on the parking brake mounting base 211, and the degrees of freedom of the rotating shaft 213 in the vertical direction are further limited.

[0077] In the embodiment, a third sealing ring 222 is arranged to abut against the parking brake mounting seat 211 and the first housing 101 respectively, i.e. the third sealing ring 222 is mainly used to seal the gap between the parking brake mounting seat 211 and the first housing 101.

[0078] In the embodiment, a fourth sealing ring 223 is arranged to abut against the parking brake mounting seat 211 and the torsion spring seat 219 respectively, i.e. the fourth sealing ring 223 is mainly used to seal the gap between the parking brake mounting seat 211 and the torsion spring seat 219.

[0079] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary, and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above-described embodiments without departing from the principles and spirit of the present application within the scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A drive axle, comprising an axle housing, an input assembly (2), two road brake assemblies (3), two coaxially distributed half shafts (103) and two hub assemblies (4), the axle housing comprising a first housing (101) and two second housings (102) fixedly connected, the two second housings (102) being respectively located on the left and right sides of the first housing (101), the road brake assembly (3) being located in the second housing (102) and sleeved on the half shaft (103), the hub assembly (4) being mounted on the outer end of the second housing (102) and fixedly connected with the outer end of the half shaft (103), and the input assembly (2) being mounted on the first housing (101); The road brake assembly comprises a first shaft sleeve (301) located in the second housing (102), an annular piston (302), a plurality of annular first outer friction plates (303) and a plurality of annular first inner friction plates (304), the first shaft sleeve (301) being in driving fit with the half shaft (103) through internal splines, the first outer friction plate (303) being in axial movable fit with the second housing (102) in circumferential positioning, the first inner friction plate (304) being in axial movable fit with the first shaft sleeve (301) in circumferential positioning, the plurality of annular first inner friction plates (304) and the first outer friction plates (303) being alternately stacked with each other, and the piston (302) being mounted on the second housing (102) and movable between a braking position and a non-braking position; characterized in that an elastic retaining ring (305) is further provided, an outer surface of the first shaft sleeve (301) is provided with an axial spline groove and a circumferential annular groove, an inner side wall of the second housing (102) is provided with a plurality of first mounting grooves, the first outer friction plate (303) is clamped in the first mounting groove, the first inner friction plate (304) is clamped in the spline groove and further coupled in driving with the first shaft sleeve (301), and the elastic retaining ring (305) is clamped in the annular groove and located between any two adjacent first inner friction plates (304), thereby completing axial positioning of the first shaft sleeve (301); wherein the first shaft sleeve (301) is in axial movable fit with the half shaft (103) in circumferential positioning through internal splines, and the thickness of the elastic retaining ring (305) is less than the thickness of the first outer friction plate (303). The input assembly (2) comprises a parking brake assembly, the parking brake assembly comprises a parking brake mounting seat (211), a pull rod (212), a rotating shaft (213), a pressure plate (214), a plurality of annular second inner friction plates (215) and a plurality of annular second outer friction plates (216), the parking brake mounting seat (211) is fixedly connected with the first shell (101) and cooperates to form a cavity (2114), the pressure plate (214) is movably arranged on the parking brake mounting seat (211), the plurality of second outer friction plates (216) are arranged in the cavity (2114) and are circumferentially positioned and axially movably cooperated, the plurality of second inner friction plates (215) are circumferentially positioned and axially movably cooperated with a transmission shaft in the input assembly (2) through a spline, the plurality of second inner friction plates (215) and the second outer friction plates (216) are alternately stacked with each other, the pull rod (212) is drivingly connected or fixedly connected with the rotating shaft (213), the rotating shaft (213) is rotatably arranged on the parking brake mounting seat (211), the rotating shaft (213) is provided with a cam portion (2131), the cam portion (2131) is formed by a groove on the side wall of the rotating shaft (213), the distance between the bottom surface in the groove and the side wall of the rotating shaft (213) gradually decreases, the end surface of the pressure plate (214) close to the rotating shaft (213) is provided with a sliding portion (2141), and the sliding portion (2141) is clamped in the groove; in the rotating process of the rotating shaft (213), the pressure plate (214) is pushed to move through cooperation of the cam portion (2131) and the pressure plate (214), so that the second inner friction plates (215) and the second outer friction plates (216) are pressed on the first shell (101); wherein, the parking brake mounting seat (211) and the rotating shaft (213) are both located outside one end of the transmission shaft, the rotating shaft (213) is provided with two cam portions (2131) corresponding in up and down directions, the two cam portions (2131) are located on the upper side and the lower side of the transmission shaft respectively, and correspondingly, the pressure plate (214) is provided with two sliding portions (2141) corresponding in up and down directions, the two sliding portions (2141) are located on the upper side and the lower side of the transmission shaft respectively.

2. A drive axle as in claim 1, wherein, A plurality of first pins (306) and a plurality of first springs (307) sleeved on the first pins (306) are further arranged, a plurality of first through holes are arranged on the first outer friction plates (303), one end of the first pin (306) penetrates through the first through holes on the plurality of first outer friction plates (303) and abuts against the second shell (102), the other end of the first pin (306) abuts against the second shaft sleeve (401), the plurality of first springs (307) are sequentially arranged between adjacent two first outer friction plates (303), and the two ends of the first spring (307) abut against the adjacent two first outer friction plates (303) respectively, so that the adjacent two first outer friction plates (303) are separated by a certain distance through the first spring (307).

3. The drive axle of claim 1 wherein, The return spring seat (308) is installed in the second housing (102), the return spring (309) moves the annular piston (302) from the braking position to the non-braking position, the annular piston (302) is uniformly distributed with a plurality of second mounting holes on the side surface, the return spring seat (308) is installed in the second mounting hole in an interference fit, the return spring screw (310) passes through the return spring seat (308) and is installed on the second housing (102), the return spring (309) is sleeved on the return spring screw (310), and one end of the return spring (309) abuts against the return spring seat (308) and the other end abuts against the return spring screw (310).

4. A drive axle as in claim 3, wherein, The return spring screw (310) limits the stroke of the return spring seat (308) to the first gap, the annular piston (302) and the return spring seat (308) move together in an interference fit, when the inner friction plate and the outer friction plate are in a non-worn state, the displacement stroke between the braking position and the non-braking position of the annular piston (302) is not greater than the first gap; when the inner friction plate and the outer friction plate are worn, the annular piston (302) and the return spring seat (308) are still fixed in an interference fit after relative displacement, the return spring screw (310) limits the stroke of the return spring seat (308) to the first gap, so that the displacement stroke between the braking position and the non-braking position of the annular piston (302) is the first gap.

5. A drive axle as in claim 3, wherein: The return spring screw (310) is provided with a first flange (3101), the center hole of the return spring seat (308) is a stepped hole, one end of the return spring (309) abuts against the first flange (3101) of the return spring screw (310), and the other end abuts against the step of the center hole of the return spring seat (308).

6. A drive axle as in claim 5, wherein, The distance between the first flange (3101) and the return spring seat (308) is the first gap, when the annular piston (302) moves from the non-braking position to the braking position, the first flange (3101) can abut against the return spring seat (308), so as to limit the stroke of the return spring seat (308) to the first gap.

7. The drive axle of claim 1 wherein, The hub assembly (4) includes a second shaft sleeve (401) and a hub piece (402), the second shaft sleeve (401) is fixedly connected with the outer end of the second housing (102) and is sleeved on the half shaft (103), and the hub piece (402) is fixedly connected with the half shaft (103). When the piston (302) moves to the braking position, the plurality of first inner friction plates (304) and the first outer friction plate (303) abut against and press on the second shaft sleeve (401).

8. A drive axle as in claim 7, wherein: The second shaft sleeve (401) comprises an integral shaft sleeve part (4011) and a flange part (4012), the flange part (4012) is fixedly installed on the outer end face of the second housing (102) through a plurality of fasteners, the other end of the first bolt (306) abuts against the inner end face of the flange part (4012), and when the piston (302) moves to the brake position, the plurality of first inner friction plates (304) and the first outer friction plate (303) are pressed on the inner end face of the flange part (4012).

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