A disconnecting central reduction gear

Abstract

The present invention discloses a disconnecting center reducer, which relates to the field of transmission devices. Through the structure of a small-sized half shaft cooperating with a universal drive shaft, a disconnecting type axle housing and half shaft are designed, thereby significantly reducing the structural strength requirements for the half shaft and the size of the axle housing. The technical solution of the present invention is as follows: It includes an axle housing, a limited-slip differential arranged in the axle housing, and two half shafts; a rotating seat that rotates synchronously with the half shaft is sleeved on the outer end of the half shaft, a fixed seat fixedly installed on the axle housing is sleeved outside the rotating seat, and end teeth are provided on the outer end face of the rotating seat; the outer end of the half shaft is butt-connected to a universal drive shaft, and the wheel side assembly is connected through the universal drive shaft, and at least one universal joint is arranged in the universal drive shaft. The present invention makes the half shaft lighter in weight and better in structural strength under the same material, and also makes the axle housing lighter in weight and smaller in volume.

Description

Technical Field

[0001] The present invention relates to the field of transmission devices, and in particular to a disconnecting central reducer. Background Art

[0002] The central reducer (also known as the main reducer) is one of the main components of the vehicle chassis transmission system. It is installed at the rear end of the transfer case assembly and is fixedly connected to the left and right longitudinal beams of the frame through a flange. Its basic function is to transmit the power output by the transfer case to the wheel side assembly through the wheel side half shaft after decelerating and increasing the torque, so as to drive the wheels to run. The main reducer assembly is provided with an interaxle differential and an interwheel differential for differential driving between axles and between the left and right wheels of the axle to improve the passability of the vehicle. The lubricating medium of the main reducer assembly is lubricated with API GL-5 heavy-duty gear oil, and different grades of gear oil are used according to different temperatures.

[0003] Most of the existing central reducers are divided into non-through type and through type. For example, as shown in the Chinese utility model patent named "Off-road vehicle through type second steering drive axle" and with the application number "022130535" disclosed on March 26, 2003, the input end of this type of structure is an input shaft flange. The input torque first passes through the interaxle differential to the through shaft, then through the main reducer to the interwheel differential, and finally is transmitted to the wheel side assembly by two half shafts.

[0004] However, whether it is non-through type or through type, the existing main reduction half shafts are between the central reducer and the wheel side assembly, and their axial lengths will be very long, with relatively large weights and moments of inertia, and very high requirements for the structural strength of the half shafts; moreover, such half shafts usually need to be installed in the axle housing, which also leads to the over-large volume and weight of the axle housing.

[0005] Therefore, how to reduce the requirements for the structural strength of the half shafts and reduce the volume and weight of the axle housing has become a technical problem that technicians in this field have been working hard to solve. Summary of the Invention

[0006] In view of the above problems, the present invention provides a disconnecting central reducer. Through the structure of small-size half shafts and universal drive shafts, a disconnecting type of axle housing and half shafts is designed, thereby significantly reducing the requirements for the structural strength of the half shafts and the size of the axle housing.

[0007] The technical solution of the present invention is as follows: As Figures 1-6 shown, it includes an axle housing, a limited-slip differential and two half shafts arranged in the axle housing. The half shafts are rotatably connected to the axle housing through bearings, and their outer ends extend out of the axle housing. The inner ends of the two half shafts are both connected to the limited-slip differential;

[0008] The outer end of the half shaft is sleeved with a rotating seat that rotates synchronously with the half shaft, and the outer end of the rotating seat is sleeved with a fixed seat fixedly installed on the bridge housing, the rotating seat abuts against the inner ring of the bearing, and the fixed seat abuts against the outer ring of the bearing. Multiple annular seals are arranged between the rotating seat and the fixed seat, and end face teeth are arranged on the outer end face of the rotating seat;

[0009] The outer end of the half-shaft is connected to the universal joint transmission shaft, which is connected to the wheel side assembly through the universal joint transmission shaft. One end of the universal joint transmission shaft is fixedly connected to the rotating seat by bolts, and the end face of the universal joint transmission shaft is provided with a driven coupling tooth that matches the end face tooth. The other end of the universal joint transmission shaft is connected to the wheel side assembly, and at least one universal joint is provided in the universal joint transmission shaft.

[0010] like Figure 2 , 4 As shown, a plurality of radial grooves are formed on the end surface of the fixed seat facing the outer ring of the bearing, the inner ports of the radial grooves are connected to the area between the rotating seat and the fixed seat, and the outer ports of the radial grooves are connected to the annular groove formed on the end surface of the fixed seat;

[0011] The bridge housing is a hollow structure, and has a cavity inside the bridge housing, and the cavity is located in the middle and lower part of the bridge housing;

[0012] A plurality of first oil holes are provided at the outer end of the bridge housing, and the two ends of the first oil holes are respectively connected to the annular groove and the cavity. A plurality of second oil holes are provided in the middle of the bridge housing, and the two ends of the second oil holes are respectively connected to the cavity and the interior of the bridge housing.

[0013] Furthermore, the inner opening of the second oil hole is arranged beside the limited slip differential.

[0014] like Figure 1 , 3 As shown, the present invention also includes a bridge box cover and a bridge box body, wherein the bridge box cover, the bridge box body and the bridge housing are fixedly connected in sequence and filled with gear oil.

[0015] As a through-type main reduction:

[0016] like Figure 3 As shown, the present invention also includes an input shaft flange rotatably connected in the bridge case cover and a through shaft coaxially arranged with the input shaft flange, one end of the through shaft is connected to the input shaft flange through the inter-axle differential, and the other end is rotatably connected to the bridge housing;

[0017] The bridge case is also provided with a driven shaft rotatably connected thereto, one end of the driven shaft being linked with the through shaft via a cylindrical gear set, and the other end being linked with the limited slip differential via a bevel gear set.

[0018] The power transmission route of the through-type main reducer is: input shaft flange - inter-axle differential - through shaft - cylindrical gear set - driven shaft - bevel gear set - limited slip differential - half shaft.

[0019] As for the non-through-type main reducer:

[0020] As Figure 1 shown, the present invention further includes an input shaft flange, a driven shaft and a bevel gear set. The input shaft flange is rotatably connected in the cross-over housing cover and fixedly connected to the driven shaft. The other end of the driven shaft is linked with the limited slip differential through the bevel gear set.

[0021] The power transmission route of the non-through-type main reducer is: input shaft flange - driven shaft - bevel gear set - limited slip differential - half shaft.

[0022] The present invention realizes the power transmission from the limited slip differential to the wheel side assembly through the structure of a small-sized half shaft and a universal drive shaft, that is, through the design of a disconnect-type half shaft, effectively solving various defects existing in the traditional half shaft. The small-sized half shaft in this case significantly shortens the axial length dimension, making the half shaft lighter in weight and better in structural strength under the same material, and the small-sized half shaft can also significantly reduce the corresponding axle housing size, making the axle housing lighter in weight and smaller in volume.

[0023] More particularly, the present invention forms a normally "inert" oil storage tank, that is, a cavity, in the inner space of the axle housing, and forms multiple oil drain holes through radial grooves before sealing, so as to largely avoid the impact of gear oil containing air bubbles on the circumferential seal, and solve the defect that the circumferential seal accompanied by the small-sized half shaft is easily damaged. Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the non-through-type main reducer,

[0025] Figure 2 is Figure 1 a partial enlarged view of A in

[0026] Figure 3 is a schematic structural diagram of the through-type main reducer,

[0027] Figure 4 is Figure 1 a partial enlarged view of B in

[0028] Figure 5 is a schematic structural diagram of the universal drive shaft,

[0029] Figure 6 is a schematic structural diagram of the end face of the universal drive shaft;

[0030] In the figure, 1 is the input shaft flange, 2 is the inter-axle differential, 3 is the through shaft, 4 is the cross-over housing cover, 5 is the driven shaft, 6 is the cylindrical gear set, 7 is the bevel gear set, 8 is the limited slip differential, 9 is the half shaft, 10 is the cross-over housing body, 11 is the axle housing, and 12 is the universal drive shaft;

[0031] 91 is the rotating seat, 92 is the fixed seat, 93 is the circumferential seal, and 94 is the face teeth;

[0032] 101 is the radial groove, 102 is the annular groove, 103 is the first oil passage hole, 104 is the cavity, and 105 is the second oil passage hole. Specific embodiments

[0033] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments in conjunction with its accompanying drawings.

[0034] As Figures 1-6 shown, the output end of the present invention includes an axle housing 11, a limited slip differential 8 provided in the axle housing 11, and two half shafts 9. The half shafts 9 are rotatably connected to the axle housing 11 through bearings, and their outer ends extend out of the axle housing 11. The inner ends of the two half shafts 9 are both connected to the limited slip differential 8;

[0035] A rotating seat 91 that rotates synchronously with the half shaft 9 is sleeved on the outer end of the half shaft 9. A fixed seat 92 fixedly installed on the axle housing 11 is sleeved outside the rotating seat 91. The rotating seat 91 abuts against the inner ring of the bearing, the fixed seat 92 abuts against the outer ring of the bearing. A plurality of circumferential seals 93, such as sealing rings, are provided between the rotating seat 91 and the fixed seat 92. Face teeth 94 are provided on the outer end face of the rotating seat 91;

[0036] The outer end of the half shaft 9 is butted against the universal drive shaft 12, and the wheel side assembly is connected through the universal drive shaft 12. One end of the universal drive shaft 12 is fixedly connected to the rotating seat 91 through bolts, and driven engaging teeth adapted to the face teeth 94 are provided on the end face of the universal drive shaft 12. The other end of the universal drive shaft 12 is connected to the wheel side assembly, and at least one universal joint is provided in the universal drive shaft 12.

[0037] In this way, the power transmission from the limited slip differential 8 to the wheel side assembly can be realized through the structure of the small-sized half shaft in cooperation with the universal drive shaft, that is, through the design of the disconnect half shaft, effectively solving various defects existing in the traditional half shaft. The small-sized half shaft in this case greatly shortens the axial length dimension, making the new half shaft lighter in weight and better in structural strength under the same material, and the small-sized half shaft can also greatly reduce the corresponding axle housing size, making the axle housing lighter in weight and smaller in volume.

[0038] Meanwhile, the applicant found that since a small-sized half shaft is adopted in this case, its sealing position will actually be closer to the center of the axle housing. The high-speed rotation of the limited-slip differential and the bevel gears at the center position of the axle housing will actually drive the gear oil in the axle housing to form a swirling flow, which is guided by the two half shafts, making the center of the swirling flow face the outer end of the half shaft and passing through the bearing to impact the circumferential seal 93 between the rotating seat 91 and the fixed seat 92.

[0039] More particularly, as the swirling flow continuously makes relative motion with the balls in the bearing, after passing through the bearing, the swirling flow will produce cavitation, thereby carrying a large number of bubbles in the gear oil impacting the circumferential seal. This undoubtedly further exacerbates the damage of the circumferential seal. This phenomenon is particularly prominent in non-through-type main reducers. Accordingly, the following optimized solutions are also proposed in this case:

[0040] As Figure 2 、 4 shown, a plurality of radial grooves 101 are formed on the end face of the fixed seat 92 facing the outer ring of the bearing. The inner ports of the radial grooves 101 communicate with the area between the rotating seat 91 and the fixed seat 92, and the outer ports of the radial grooves 101 are in communication with an annular groove 102 formed on the end face of the fixed seat 92.

[0041] The axle housing 11 is of a hollow structure, and has a cavity 104 inside the axle housing 11. The cavity 104 is located in the middle and lower parts of the axle housing 11.

[0042] A plurality of first oil through holes 103 are formed at the outer end of the axle housing 11. The two ends of the first oil through holes 103 communicate with the annular groove 102 and the cavity 104 respectively. A plurality of second oil through holes 105 are formed in the middle of the axle housing 11. The two ends of the second oil through holes 105 communicate with the cavity 104 and the inside of the axle housing 11 respectively.

[0043] The inner orifices of a plurality of second oil through holes 105 are arranged beside or close to the limited-slip differential 8.

[0044] In this way, an "inert" oil storage tank, that is, the cavity 104, is formed in the inner space of the housing of the axle housing 11, and a plurality of oil discharge holes are formed through the radial grooves 101 before sealing, so as to largely avoid the impact of gear oil containing bubbles on the circumferential seal, and solve the defect that the circumferential seal is easily damaged accompanied by the small-sized half shaft.

[0045] Specifically, when the half shaft does not rotate, the circumferential seal functions properly to provide sealing, and the cavity is affected by gravity to store oil. As the half shaft starts to rotate and accelerates continuously, the gear oil in the axle housing begins to form a swirl, and cavitation occurs when passing through the ball bearing. At this time, affected by the swirl and guided by the half shaft, the gear oil continuously accumulates towards the position where the bearing is located, and starts to suck the gear oil in the oil storage tank from the second oil passage hole 105, thereby generating a suction force in the first oil passage hole 103 and the annular groove 102, making the radial groove 101 become an oil drain hole, and continuously sucking the gear oil impacting the circumferential seal into the oil storage tank, greatly reducing the impact on the circumferential seal and effectively protecting the circumferential seal.

[0046] As Figure 1 , 3 shown, the present invention also generally includes a cross-over cover 4 and a cross-over housing 10. The cross-over cover 4, the cross-over housing 10 and the axle housing 11 are fixedly connected in sequence, and are filled with gear oil therein.

[0047] As a through-type main reducer:

[0048] As Figure 3 shown, the present invention also includes an input shaft flange 1 rotatably connected in the cross-over cover 4 and a through shaft 3 coaxially arranged with the input shaft flange 1. One end of the through shaft 3 is connected to the input shaft flange 1 through an inter-axle differential 2, and the other end is rotatably connected to the axle housing 11. A driven shaft 5 rotatably connected thereto is also provided in the cross-over housing 10. One end of the driven shaft 5 is kept in linkage with the through shaft 3 through a cylindrical gear set 6, and the other end is kept in linkage with a limited-slip differential 8 through a bevel gear set 7.

[0049] The power transmission route of the through-type main reducer is input shaft flange 1 - inter-axle differential 2 - through shaft 3 - cylindrical gear set 6 - driven shaft 5 - bevel gear set 7 - limited-slip differential 8 - half shaft 9.

[0050] As a non-through-type main reducer:

[0051] As Figure 1 shown, the present invention also includes an input shaft flange 1, a driven shaft 5 and a bevel gear set 7. The input shaft flange 1 is rotatably connected in the cross-over cover 4 and is fixedly connected to the driven shaft 5. The other end of the driven shaft 5 is kept in linkage with a limited-slip differential 8 through a bevel gear set 7.

[0052] The power transmission route of the non-through-type main reducer is input shaft flange 1 - driven shaft 5 - bevel gear set 7 - limited-slip differential 8 - half shaft 9.

[0053] There are many specific implementation approaches for the present invention. The above description is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art of this technology, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A disconnecting central reduction gear, characterized in that, It includes a bridge housing (11), a limited slip differential (8) and two half shafts (9) provided in the bridge housing (11). The half shafts (9) are rotatably connected to the bridge housing (11) through bearings, and their outer ends extend out of the bridge housing (11). The inner ends of the two half shafts (9) are both connected to the limited slip differential (8). A rotating seat (91) that rotates synchronously with the half shaft (9) is sleeved on the outer end of the half shaft (9). A fixed seat (92) fixedly installed on the bridge housing (11) is sleeved outside the rotating seat (91). The rotating seat (91) abuts against the inner ring of the bearing, and the fixed seat (92) abuts against the outer ring of the bearing. A plurality of circumferential seals (93) are provided between the rotating seat (91) and the fixed seat (92). End teeth (94) are provided on the outer end face of the rotating seat (91). The outer end of the half shaft (9) is butted against a universal drive shaft (12), and the wheel side assembly is connected through the universal drive shaft (12). One end of the universal drive shaft (12) is fixedly connected to the rotating seat (91) by bolts, and driven engaging teeth adapted to the end teeth (94) are provided on the end face of the universal drive shaft (12). The other end of the universal drive shaft (12) is connected to the wheel side assembly. At least one universal joint is provided in the universal drive shaft (12). A plurality of radial grooves (101) are formed on the end face of the fixed seat (92) facing the outer ring of the bearing. The inner ports of the radial grooves (101) communicate with the area between the rotating seat (91) and the fixed seat (92), and the outer ports of the radial grooves (101) are in communication with an annular groove (102) formed on the end face of the fixed seat (92). The bridge housing (11) is of a hollow structure, and a cavity (104) is provided inside the bridge housing (11). The cavity (104) is located in the middle and lower parts of the bridge housing (11). A plurality of first oil through holes (103) are formed at the outer end heads of the bridge housing (11). The two ends of the first oil through holes (103) communicate with the annular groove (102) and the cavity (104) respectively. A plurality of second oil through holes (105) are formed in the middle of the bridge housing (11). The two ends of the second oil through holes (105) communicate with the cavity (104) and the inside of the bridge housing (11) respectively. The inner orifice of the second oil through hole (105) is arranged at a position close to the limited slip differential (8). The cavity (104) serves as an oil storage tank formed in the inner space of the housing of the bridge housing (11). When the half shaft does not rotate, the cavity (104) functions as an oil storage. As the half shaft starts to rotate and accelerates continuously, the gear oil in the bridge housing starts to form a swirling flow. The gear oil continuously accumulates towards the position where the bearing is located, and starts to suck the gear oil in the oil storage tank from the second oil through hole (105), thereby forming a suction force in the first oil through hole (103) and the annular groove (102), making the radial groove (101) become an oil drain hole, and continuously sucking the gear oil impacting the circumferential seal into the oil storage tank.

2. The disconnecting central speed reducer according to claim 1, wherein It further includes a cross-over housing cover (4) and a cross-over housing body (10). The cross-over housing cover (4), the cross-over housing body (10) and the axle housing (11) are fixedly connected in sequence, and gear oil is filled therein.

3. The disconnecting central speed reducer according to claim 2, characterized in that, It further includes an input shaft flange (1) rotatably connected in the cross-over housing cover (4), a through shaft (3) arranged coaxially with the input shaft flange (1), and a driven shaft (5) rotatably connected in the cross-over housing body (10). One end of the through shaft (3) is connected to the input shaft flange (1) through an inter-axle differential (2), and the other end is rotatably connected to the axle housing (11). One end of the driven shaft (5) is linked with the through shaft (3) through a cylindrical gear set (6), and the other end is linked with a limited-slip differential (8) through a bevel gear set (7).

4. The disconnecting type central speed reducer according to claim 2, wherein, It further includes an input shaft flange (1), a driven shaft (5) and a bevel gear set (7). The input shaft flange (1) is rotatably connected in the cross-over housing cover (4) and is fixedly connected to the driven shaft (5). The other end of the driven shaft (5) is linked with a limited-slip differential (8) through a bevel gear set (7).

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