A planetary three-speed gearbox

Abstract

The present invention relates to the technical field of motor vehicle shifting, and in particular to a planetary gearbox of three gears, which comprises a first brake shifting mechanism, a second brake shifting mechanism, a clutch shifting mechanism and a gear transmission mechanism; the first brake shifting mechanism and the second brake shifting mechanism share the same brake sleeve; the clutch shifting mechanism comprises a clutch and a clutch sleeve; the gear transmission mechanism comprises a gear ring and a sun gear seat; in the first brake shifting mechanism, the outer teeth of the brake sleeve are slidably connected with the inner teeth of the housing, and the inner teeth of the brake sleeve can be connected with the sun gear seat; in the second brake shifting mechanism, the outer teeth of the brake sleeve are slidably connected with the inner teeth of the housing, and the inner teeth of the brake sleeve can be connected with the gear ring, and the inner teeth of the clutch sleeve are slidably connected with the outer teeth of the oil cylinder and can be connected with the sun gear seat. The planetary gearbox of three gears has a wider speed range, and improves the performance of the whole vehicle by automatically switching the three speed ratios of the gearbox.

Description

Technical Field

[0001] The invention relates to the technical field of motor vehicle shifting, and in particular to a planetary three-speed gearbox. Background Art

[0002] The torque and speed of the engine used in the drive device of the automobile have a limited range of variation, which cannot meet the various driving conditions of the automobile and provide the torque and speed required by the automobile under various working conditions. Therefore, the automobile needs to be equipped with a gearbox for shifting gears. The gearbox changes the engine torque and speed according to the driving conditions of the automobile to meet the requirements of various driving conditions of the automobile.

[0003] Since the motor speed range is wider than that of the engine and can meet most of the driving conditions of the car, the electric vehicle gearbox does not need to have multiple gears like the traditional gearbox. The more gears the gearbox has, the more complex the gearbox structure is, which increases the weight of the vehicle and the cost. Since the structure and control of the automatic gearbox are more complex than the manual gearbox, electric vehicles currently mainly use fixed-speed ratio gearboxes that cannot change speed, affecting the performance of the vehicle. Under the condition of the same battery capacity, fixed-speed ratio gearboxes need to output more power than multi-speed gearboxes, reducing the vehicle's cruising range. For the same cruising range, if equipped with a higher-power motor or a larger-capacity battery, it will not only increase the weight and cost of the vehicle, but also increase the power loss and energy consumption of the vehicle. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In order to solve the above problems in the prior art, the present invention provides a planetary three-speed gearbox.

[0006] (II) Technical solution

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] The present invention provides a planetary three-speed gearbox, which includes a housing, a shell, a first brake shift mechanism, a second brake shift mechanism, a clutch shift mechanism and a gear transmission mechanism;

[0009] The shell is fixedly connected to the housing;

[0010] The first brake shift mechanism and the second brake shift mechanism share a same brake sleeve;

[0011] The clutch shifting mechanism comprises a clutch and a clutch sleeve;

[0012] The gear transmission mechanism includes a ring gear and a sun gear seat;

[0013] In the first brake shift mechanism, the outer teeth of the brake sleeve are slidably connected with the inner teeth of the housing, and the brake sleeve moves axially along the inner teeth of the housing and can be connected with the outer teeth of the sun gear seat;

[0014] In the second brake shift mechanism, the outer teeth of the brake sleeve are slidably connected with the inner teeth of the housing, and the brake sleeve moves axially along the inner teeth of the housing and can be connected with the outer teeth of the gear ring;

[0015] The clutch comprises an oil cylinder, the inner teeth of the clutch sleeve are slidably connected with the large-diameter outer teeth of the oil cylinder, and the clutch sleeve moves axially along the large-diameter outer teeth of the oil cylinder and can be connected with the end teeth of the sun gear seat.

[0016] According to the present invention, the first brake shift mechanism further comprises a first brake, and the first brake comprises a first piston, a first spring, and a first spring seat;

[0017] The housing is provided with a positioning boss, and the positioning boss limits the axial position of the first piston;

[0018] The housing is also provided with two annular grooves, namely a first annular groove and a second annular groove, wherein a first retaining spring is installed in the first annular groove for axial limiting, and a second retaining spring is installed in the second annular groove for axial limiting;

[0019] The first spring seat is axially limited by the first retaining spring;

[0020] The first spring is placed between the first piston and the first spring seat, one end of the first spring contacts the first spring seat, and the other end of the first spring contacts the first piston.

[0021] According to the present invention, the first brake further comprises a first pair of plates and a first friction plate;

[0022] The first pair of plates and the first friction plate are placed at intervals, the first pair of plates are spline-connected to the housing, and the first friction plate is spline-connected to the sun gear seat.

[0023] According to the present invention, the second brake shift mechanism further comprises a second brake, and the second brake comprises a second piston, a second spring, and a second spring seat;

[0024] The housing is provided with a positioning boss, and the positioning boss limits the axial position of the second piston;

[0025] The housing is also provided with two annular grooves, namely a third annular groove and a fourth annular groove, wherein a third retaining spring is installed in the third annular groove for axial limiting, and a fourth retaining spring is installed in the fourth annular groove for axial limiting;

[0026] The second spring seat is axially limited by the second retaining spring;

[0027] The second spring is placed between the second piston and the second spring seat, one end of the second spring contacts the second spring seat, and the other end of the second spring contacts the second piston.

[0028] According to the present invention, the second brake further comprises a second pair of plates and a second friction plate;

[0029] The second pair of plates and the second friction plate are placed at intervals, the second pair of plates are spline-connected to the housing, and the second friction plate is spline-connected to the gear ring.

[0030] According to the present invention, the gear transmission mechanism comprises an input shaft, a large sun gear, a long planet gear, a short planet gear and a planet gear shaft;

[0031] A small sun gear is fixedly arranged on the input shaft, and the large sun gear is sleeved on the input shaft via a sixth bearing, and there is a gap between the large sun gear and the small sun gear;

[0032] The sun gear seat is spline-connected to the large sun gear;

[0033] The large sun gear is provided with a fifth annular groove, in which a fifth retaining spring is installed for axial limiting.

[0034] According to the present invention, the long planetary gear and the short planetary gear are sleeved on the planetary gear shaft, planetary carriers are fixed at both ends of the planetary gear shaft, and the planetary carriers are rotatably connected to the sun gear seat;

[0035] The short planetary gear is meshed with the small sun gear, and the long planetary gear is meshed with the large sun gear;

[0036] The short planetary gears are meshed with the long planetary gears and the ring gear respectively.

[0037] According to the present invention, the clutch comprises a third piston, a balancing piston, a third spring, and a positioning boss is provided on the oil cylinder, and the positioning boss limits the axial position of the third piston;

[0038] The large diameter inner teeth and the small diameter outer circle of the oil cylinder are respectively provided with a sixth annular groove and a seventh annular groove, wherein a sixth retaining spring is installed in the sixth annular groove for axial limit, and a seventh retaining spring is installed in the seventh annular groove for axial limit;

[0039] The balancing piston is axially limited by the sixth retaining spring; the third spring is placed between the third piston and the balancing piston, one end of the third spring is in contact with the third piston, and the other end is in contact with the balancing piston.

[0040] According to the present invention, the clutch device further comprises a third pair of plates and a third friction plate;

[0041] The third pair of plates and the third friction plate are spaced apart, the third pair of plates are spline-connected to the oil cylinder, and the third friction plate is spline-connected to the sun gear seat.

[0042] According to the present invention, the oil cylinder sleeve is arranged on the input shaft, and the oil cylinder small diameter inner spline is connected with the input shaft spline.

[0043] (III) Beneficial effects

[0044] The beneficial effects of the present invention are as follows: the planetary three-speed gearbox of the present invention has a wider speed range, and the automatic switching of the three speed ratios of the gearbox can better meet the requirements of the economy and acceleration of the whole vehicle, and improve the performance of the whole vehicle. Under the same cruising range conditions, the planetary three-speed gearbox can reduce the battery capacity, reduce the weight and cost of the whole vehicle, and the power loss and energy consumption of the whole vehicle. Under the same battery capacity conditions, the planetary three-speed gearbox can output a smaller power current than the transmission gearbox, thereby increasing the cruising range of the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is the structural diagram of the automatic transmission of the present invention.

[0046] [Description of Reference Numerals]

[0047] 1: housing; 2: first piston; 3: first spring; 4: first retaining spring; 5: first spring seat; 6: sun gear seat; 7: first pair of plates; 8: first friction plate; 9: second retaining spring; 10: first bearing; 11: planetary gear shaft; 12: brake sleeve; 13: long planetary gear; 14: third retaining spring; 15: second pair of plates; 16: second friction plate; 17: gear ring; 18: second spring seat; 19: fourth retaining spring; 20: second spring; 21: second piston; 22: housing;

[0048] 23: input shaft; 24: second bearing; 25: third bearing; 26: fourth bearing; 27: short planetary gear; 28: planetary carrier; 29: fifth bearing; 30: sixth bearing; 31: large sun gear; 32: seventh bearing; 33: clutch sleeve; 34: third pair of plates; 35: third friction plate; 36: oil cylinder; 37: third piston; 38: balance piston; 39: third spring; 40: fifth retaining spring; 41: sixth retaining spring; 42: eighth bearing; 43: ninth bearing; 44: tenth bearing; 45: seventh retaining spring. DETAILED DESCRIPTION

[0049] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0050] The present invention provides a planetary three-speed gearbox, such as Figure 1 As shown, the gearbox includes two brake shifting mechanisms, a clutch shifting mechanism and a gear transmission mechanism.

[0051] The brake shift mechanism includes a first brake shift mechanism and a second brake shift mechanism. The first brake shift mechanism includes a first brake and a brake sleeve. The second brake shift mechanism includes a second brake and a brake sleeve. The first brake shift mechanism and the second brake shift mechanism share the same brake sleeve, namely, the brake sleeve 12.

[0052] The first brake shifting mechanism includes a first brake and a brake sleeve 12 . The first brake includes a first piston 2 , a first spring 3 , a first retaining spring 4 , a first spring seat 5 , a first pair of plates 7 , a first friction plate 8 , and a second retaining spring 9 .

[0053] The second brake shifting mechanism comprises a second brake and a brake sleeve 12 . The second brake comprises a third retaining spring 14 , a second pair of plates 15 , a second friction plate 16 , a second spring seat 18 , a fourth retaining spring 19 , a second spring 20 , and a second piston 21 .

[0054] The clutch shift mechanism includes a clutch and a clutch sleeve 33. The clutch includes an oil cylinder 36, a third piston 37, a balance piston 38, a third spring 39, a third pair of plates 34, a third friction plate 35, a fifth retaining spring 41, and a sixth retaining spring 45.

[0055] The gear transmission mechanism includes a ring gear 17 , an input shaft 23 , a large sun gear 31 , a planet carrier 28 , long planet gears 13 , short planet gears 27 , a planet gear shaft 11 and a sun gear seat 6 .

[0056] The planetary three-speed gearbox comprises a housing 1 and a shell 22 , wherein the housing 1 is fixedly connected to the shell 22 .

[0057] The clutch or brake actuator includes hydraulic type and electronically controlled type. In this example, a hydraulic clutch is selected, which is composed of a cylinder, a piston and a spring. The clutch actuator can also be electronically controlled, consisting of a motor, a reduction mechanism and an axial propulsion mechanism.

[0058] Gear transmission mechanism

[0059] A small sun gear is fixedly mounted on the input shaft 23 and is provided with external teeth. A large sun gear 31 is provided with external teeth and is loosely mounted on the input shaft 23 via a sixth bearing 30 . There is a gap between the large sun gear 31 and the small sun gear.

[0060] The long planet gear 13 and the short planet gear 27 are both provided with external teeth. The short planet gear 27 meshes with the small sun gear, and the long planet gear 13 meshes with the large sun gear 31 .

[0061] The short planetary gear 27 is covered with a gear ring 17 , and the inner and outer rings of the gear ring 17 are provided with teeth. The short planetary gear 27 is meshed with the long planetary gear 13 and the inner teeth of the gear ring 17 , respectively. The gear ring 17 is axially positioned by the third bearing 25 .

[0062] The long planetary gear 13 and the short planetary gear 27 are loosely supported on the planetary gear shaft 11 through the first bearing 10 . Planet carriers 28 are fixed at both ends of the planetary gear shaft 11 . The planet carrier 28 close to the housing 22 is axially limited by the fourth bearing 26 and the third bearing 25 .

[0063] The large sun gear 31 is provided with a fifth annular groove, in which a fifth circlip 40 is installed for axial limiting. The large diameter outer circle of the sun gear seat 6 is provided with small external teeth and large external teeth respectively, and the small diameter inner circle is provided with internal splines, which are connected with the external splines of the large sun gear 31. The planet carrier 28 near the oil cylinder 36 side is axially limited by the seventh bearing 32, and the sun gear seat 6 near the oil cylinder 36 side is provided with teeth at both ends.

[0064] One end of the clutch sleeve 33 close to the sun gear seat 6 is provided with teeth, which can be connected with the teeth of one end of the sun gear seat 6 close to the oil cylinder 36.

[0065] The brake sleeve 12 is provided with internal teeth, which can be connected with the large external teeth of the sun gear seat 6 .

[0066] First brake shift mechanism

[0067] The housing 1 is provided with two annular grooves, namely a first annular groove and a second annular groove, wherein a first retaining spring 4 is installed in the first annular groove for axial limitation, and a second retaining spring 9 is installed in the second annular groove for axial limitation.

[0068] The housing 1 is provided with a positioning boss, and the first piston 2 contacts the positioning boss for axial limitation. The major diameter and minor diameter of the first piston 2 have sealing structures that contact the outer diameter and inner diameter of the housing 1 respectively, and the first spring seat 5 is axially limited by the first retaining spring 4. The first spring seat 5 has no contact with the first piston 3. The inner diameter of the first spring seat 5 is clearance-matched with the housing 1, and the other end contacts the first retaining spring 4 and is axially limited on the housing 1.

[0069] The first spring 3 is disposed between the first piston 2 and the first spring seat 5 , one end of the first spring 3 is in contact with the first spring seat 14 , and the other end of the first spring 3 is in contact with the first piston 2 .

[0070] The outer shell 1 is provided with internal teeth, the first pair of plates 7 is provided with external teeth, the first friction plate 8 is provided with internal teeth, the first pair of plates 7 and the first friction plate 8 are placed at intervals, the external teeth of the first pair of plates 7 are connected to the internal teeth of the outer shell 1, and the internal teeth of the first friction plate 8 are connected to the large external teeth of the sun gear seat 6.

[0071] The outer ring of the brake sleeve 12 is provided with external teeth, which are slidably connected with the inner teeth of the housing 1, and the brake sleeve 12 can move axially along the inner teeth of the housing 1. The inner ring of the brake sleeve 12 is provided with internal teeth, which can be connected with the large external teeth of the sun gear seat 6.

[0072] Second brake shift mechanism

[0073] The housing 22 is provided with two annular grooves, namely a third annular groove and a fourth annular groove. A third retaining spring 14 is installed in the third annular groove for axial limiting, and a fourth retaining spring 19 is installed in the fourth annular groove for axial limiting.

[0074] The housing 22 is provided with a positioning boss, and the second piston 21 contacts the positioning boss for axial limitation. The second piston 21 has a sealing structure for both the major diameter and the minor diameter, which contact the outer diameter and the inner diameter of the housing 22 respectively. The second spring seat 18 is axially limited by the fourth retaining spring 19. The inner diameter of the second spring seat 18 is clearance-matched with the housing 22, and the other end contacts the fourth retaining spring 19 and is axially limited on the housing 22.

[0075] The second spring 20 is disposed between the second piston 21 and the second spring seat 18 . One end of the second spring 20 is connected to the second spring seat 18 , and the other end of the second spring 20 is connected to the second piston 21 .

[0076] The housing 22 is provided with internal teeth, the second pair of plates 15 are provided with external teeth, the second friction plate 16 is provided with internal teeth, the second pair of plates 15 and the second friction plate 16 are placed at intervals, the second pair of plates external teeth 15 are connected to the internal teeth of the housing 22, and the internal teeth of the second friction plate 16 are connected to the external teeth of the gear ring 17.

[0077] The outer ring of the brake sleeve 12 is provided with external teeth, which are slidably connected to the inner teeth of the housing 22. The brake sleeve 12 can move axially along the inner teeth of the housing 22. The inner ring of the brake sleeve 12 is provided with internal teeth, which can be connected to the outer teeth of the gear ring 17.

[0078] Clutch shift mechanism

[0079] The large diameter inner teeth of the oil cylinder 36 are provided with a sixth annular groove, in which a sixth retaining spring 41 is installed for axial limiting. The small diameter outer circle of the oil cylinder 36 is provided with a seventh annular groove, in which a seventh retaining spring 45 is installed for axial limiting.

[0080] A positioning boss is provided on the side of the oil cylinder 36 close to the housing 1, and the third piston 37 contacts the positioning boss for axial limitation. The third piston 37 has a sealing structure on both the major diameter and the minor diameter, which contact the outer diameter and the inner diameter of the oil cylinder 36 respectively. The balancing piston 38 is axially limited by the sixth retaining spring 41. The major diameter of the balancing piston 38 has a sealing structure in contact with the inner diameter of the third piston 37; the minor diameter has a large gap with the outer diameter of the oil cylinder 36, and the other end contacts the sixth retaining spring 41 and is axially limited on the oil cylinder 36.

[0081] The third spring 39 is disposed between the third piston 37 and the balancing piston 4 . One end of the third spring 39 is connected to the third piston 39 , and the other end of the third spring 39 is connected to the balancing piston 4 .

[0082] The housing 1 is rotatably connected to the input shaft 23, a tenth bearing 43 is provided at the connection position, a ninth bearing 42 is provided between the housing 1 and the input shaft 23, the oil cylinder 36 is sleeved on the input shaft 23, and the oil cylinder 2 is provided with an internal spline in a small diameter, which is connected to the external spline of the input shaft 23.

[0083] The large diameter inner circle and the large diameter outer circle of the oil cylinder 36 are respectively provided with internal teeth and external teeth, the third pair of plates 34 are provided with external teeth, and the third friction plate 35 is provided with internal teeth, wherein the third pair of plates 34 and the third friction plate 35 are placed at intervals, the internal teeth of the third pair of plates 34 are connected to the internal teeth of the oil cylinder 36, and the internal teeth of the third friction plate 35 are connected to the large external teeth of the sun gear seat 6.

[0084] The clutch sleeve 33 is provided with internal teeth, and the internal teeth of the clutch sleeve 33 are slidably connected with the large-diameter external teeth of the cylinder 36. The clutch sleeve 33 moves axially along the large-diameter external teeth of the cylinder 36. The end of the clutch sleeve 33 close to the sun gear seat 6 is provided with teeth, which can be connected with the teeth of the end of the sun gear seat 6 close to the cylinder 36.

[0085] Specific workflow:

[0086] When the clutch shift mechanism shifts gears, the oil cylinder 36 and the third piston 37 form a closed space. After the pressure oil enters the closed space, it pushes the third piston 37 to move axially away from the oil cylinder 36, and the third piston 37 contacts the third dual plate 34.

[0087] At the same time, the operating mechanism of the clutch sleeve 33 pushes the clutch sleeve 33 to move axially along the large-diameter outer teeth of the cylinder 36 toward the sun gear seat 6. When the third pair of plates 34 and the third friction plates 35 gradually contact and form sliding friction, and the input, i.e., the rotation speed of the cylinder 36 and the output, i.e., the rotation speed of the sun gear seat 6, are very small, i.e., synchronized, the clutch sleeve 33 and the sun gear seat 6 are directly and rigidly connected to transmit power, and the clutch shifting is completed.

[0088] The pressure oil in the clutch cylinder 36 and the cooling lubricating oil of the third friction plate 35 can be disconnected, and the third piston 37 returns to its original position under the action of the third spring 39. There is no pressing force between the third friction plate 35 and the third dual plate 34, and power cannot be transmitted.

[0089] When the clutch shift mechanism is working, the power is input from the input shaft 23, rigidly connected to the sun gear seat 6 through the clutch sleeve 33, and finally directly outputted by the planet carrier 28 in a 1:1 ratio. All the input power is directly transmitted by the rigid connection between the clutch sleeve 33 and the sun gear seat 6, without power loss, thus improving the transmission efficiency of the gearbox.

[0090] When the first brake shift mechanism shifts gears, the housing 1 and the first piston 2 form a closed space. After the pressure oil enters the closed space, it pushes the first piston 2 to move axially toward the sun gear seat 6, and the first piston 2 contacts the first pair of plates 7.

[0091] At the same time, the operating mechanism of the brake sleeve 12 pushes the brake sleeve 12 to move axially along the inner teeth of the outer shell 1 in the direction close to the sun gear seat 6. When the first pair of plates gradually contact with the first friction plate 8 and form sliding friction, and the rotation speed of the sun gear seat 6 is synchronized with the rotation speed of the outer shell 1, the inner teeth of the inner ring of the brake sleeve 12 are directly and rigidly connected with the large outer teeth of the sun gear seat 6, locking the sun gear seat 6, and the brake shifting is completed.

[0092] The pressure oil of the brake housing 1 and the cooling lubricating oil of the first friction plate 8 can be disconnected, and the first piston 2 returns to its original position under the action of the first spring 4. There is no clamping force between the first friction plate 8 and the first pair of plates 7, and the sun gear seat 6 cannot be locked.

[0093] When the first brake shift mechanism is working, power is input from the input shaft 23, the small sun gear is meshed with the short planetary gear 27, the short planetary gear 27 is meshed with the long planetary gear 13, the long planetary gear 13 is meshed with the large sun gear 31, the large sun gear 31 is splined with the sun gear seat 6 to be locked, and the speed is changed by the planetary gear, and finally output by the planet carrier 28. The entire locking torque of the sun gear seat 6 is directly transmitted by the rigid connection between the brake sleeve 12 and the housing 1, without power loss, thereby improving the transmission efficiency of the gearbox.

[0094] When the second brake shift mechanism shifts gears, the housing 22 and the second piston 23 form a closed space. After the pressure oil enters the closed space, it pushes the second piston 32 to move axially toward the oil cylinder 36, and the second piston 23 contacts the second dual plate 15.

[0095] At the same time, the operating mechanism of the brake sleeve 12 pushes the brake sleeve 12 to move axially along the inner teeth of the housing 22 in the direction away from the sun gear seat 6. When the second pair of plates 15 and the second friction plates 16 gradually contact and form sliding friction, and the rotation speed of the ring gear 17 is synchronized with the rotation speed of the housing 22, the inner teeth of the brake sleeve 12 are directly and rigidly connected with the outer teeth of the ring gear 17, locking the ring gear 17, and the brake shifting is completed.

[0096] The pressure oil in the brake housing 22 and the cooling lubricating oil of the second friction plate 16 can be disconnected, and the second piston 21 returns to its original position under the action of the second spring 20. There is no clamping force between the second friction plate 16 and the second pair of plates 15, and the ring gear 17 cannot be locked.

[0097] When the second brake shift mechanism is working, power is input from the input shaft 23, the small sun gear is meshed with the short planetary gear 27, the short planetary gear 27 is meshed with the ring gear 17, the ring gear 17 is locked, and finally output by the planet carrier 28 after the planetary gear speed change. The entire locking torque of the ring gear 17 is directly transmitted by the rigid connection between the brake sleeve 12 and the housing 22, without power loss.

[0098] The planetary three-speed gearbox of the present invention has a wider speed range, and the automatic switching of the three speed ratios of the gearbox can better meet the requirements of the economy and acceleration of the whole vehicle, and improve the performance of the whole vehicle. Under the same cruising range, the planetary three-speed gearbox can reduce the battery capacity, reduce the weight and cost of the whole vehicle, and the power loss and energy consumption of the whole vehicle. Under the same battery capacity, the planetary three-speed gearbox can output a smaller power current than the traditional gearbox, which increases the cruising range of the whole vehicle. The clutch and brake in the shifting structure only work when the gearbox is shifted. After the shifting is completed, the clutch and brake are opened, and the clutch sleeve and the brake sleeve are rigidly connected with their connecting parts to replace the clutch and the brake to transmit power. The clutch sleeve and the brake sleeve are both provided with teeth, and can move axially and be connected with matching parts. After being connected with matching parts, power is transmitted, which greatly reduces the loss of the gearbox, improves the transmission efficiency, avoids the risk of overload slipping, increases the service life of the clutch and the brake, and improves the reliability and quality of the gearbox.

[0099] It should be understood that the above description of the specific embodiments of the present invention is only for illustrating the technical route and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but the present invention is not limited to the above specific implementation methods. Any changes or modifications made within the scope of the claims of the present invention should be included in the protection scope of the present invention.

Claims

1. A planetary three-speed gearbox, characterized in that: The gearbox comprises a housing (1), a shell (22), a first brake shifting mechanism, a second brake shifting mechanism, a clutch shifting mechanism and a gear transmission mechanism; The housing (1) is fixedly connected to the casing (22); The first brake shift mechanism and the second brake shift mechanism share a same brake sliding sleeve (12); The clutch shifting mechanism comprises a clutch and a clutch sleeve (33); The gear transmission mechanism comprises a ring gear (17) and a sun gear seat (6); In the first brake shift mechanism, the outer teeth of the brake sleeve (12) are slidably connected to the inner teeth of the housing (1), and the brake sleeve (12) moves axially along the inner teeth of the housing (1) and can be connected to the outer teeth of the sun gear seat (6); The first brake shifting mechanism comprises a first brake, and the first brake comprises a first piston (2), a first spring (3), a first spring seat (5), a first pair of plates (7) and a first friction plate (8); The housing (1) is provided with a positioning boss, and the positioning boss limits the axial position of the first piston (2); The housing (1) is also provided with two annular grooves, namely a first annular groove and a second annular groove, wherein a first retaining spring (4) is installed in the first annular groove for axial limiting, and a second retaining spring (9) is installed in the second annular groove for axial limiting; The first spring seat (5) is axially limited by the first clamping spring (4); The first spring (3) is disposed between the first piston (2) and the first spring seat (5), one end of the first spring (3) is in contact with the first spring seat (5), and the other end of the first spring (3) is in contact with the first piston (2); The first pair of plates (7) and the first friction plate (8) are placed at intervals, the first pair of plates (7) are spline-connected to the housing (1), and the first friction plate (8) is spline-connected to the sun gear seat (6); In the second brake shift mechanism, the outer teeth of the brake sleeve (12) are slidably connected to the inner teeth of the housing (22), and the brake sleeve (12) moves axially along the inner teeth of the housing (22) and can be connected to the outer teeth of the gear ring (17); The second brake shifting mechanism comprises a second brake, and the second brake comprises a second piston (21), a second spring (20), a second spring seat (18), a second pair of plates (15) and a second friction plate (16); The housing (22) is provided with a positioning boss, and the positioning boss limits the axial position of the second piston (21); The housing (22) is also provided with two annular grooves, namely a third annular groove and a fourth annular groove, wherein a third retaining spring (14) is installed in the third annular groove for axial limiting, and a fourth retaining spring (19) is installed in the fourth annular groove for axial limiting; The second spring seat (18) is axially limited by the second clamping spring (9); The second spring (20) is disposed between the second piston (21) and the second spring seat (18), one end of the second spring (20) is in contact with the second spring seat (18), and the other end is in contact with the second piston (21); The second pair of plates (15) and the second friction plate (16) are placed at intervals, the second pair of plates (15) are spline-connected to the housing (22), and the second friction plate (16) is spline-connected to the gear ring (17); The clutch comprises an oil cylinder (36), a third piston (37), a balancing piston (38), a third spring (39), a third pair of plates (34) and a third friction plate (35); the inner teeth of the clutch sleeve (33) are slidably connected with the outer teeth of the oil cylinder (36); the clutch sleeve (33) moves axially along the outer teeth of the oil cylinder (36) and can be connected with the end teeth of the sun gear seat (6); The oil cylinder (36) is provided with a positioning boss, and the positioning boss limits the axial position of the third piston (37); The large-diameter inner teeth and the small-diameter outer circle of the oil cylinder (36) are respectively provided with a sixth annular groove and a seventh annular groove, wherein a sixth retaining spring (41) is installed in the sixth annular groove for axial limiting, and a seventh retaining spring (45) is installed in the seventh annular groove for axial limiting; The balancing piston (38) is axially limited by the sixth retaining spring (41); the third spring (39) is disposed between the third piston (37) and the balancing piston (38); one end of the third spring (39) is in contact with the third piston (37), and the other end is in contact with the balancing piston (38); The third pair of plates (34) and the third friction plates (35) are spaced apart from each other, the third pair of plates (34) are spline-connected to the oil cylinder (36), and the third friction plates (35) are spline-connected to the sun gear seat (6); The oil cylinder (36) is sleeved on the input shaft (23), and the small-diameter inner spline of the oil cylinder (36) is connected to the outer spline of the input shaft (23).

2. The planetary three-speed gearbox according to claim 1, characterized in that: The gear transmission mechanism comprises an input shaft (23), a large sun gear (31), a long planetary gear (13), a short planetary gear (27) and a planetary gear shaft (11); The gear ring (17) is sleeved on the input shaft (23), a small sun gear is fixedly provided on the input shaft (23), the large sun gear (31) is sleeved on the input shaft (23) via a sixth bearing (30), and there is a gap between the large sun gear (31) and the small sun gear; The sun gear seat (6) is spline-connected to the large sun gear (31); The large sun gear (31) is provided with a fifth annular groove, in which a fifth retaining spring (40) is installed for axial limiting.

3. The planetary three-speed gearbox according to claim 2, characterized in that: The long planetary gear (13) and the short planetary gear (27) are sleeved on the planetary gear shaft (11), and planetary carriers (28) are fixed at both ends of the planetary gear shaft (11), and the planetary carrier (28) is rotatably connected to the sun gear seat (6); The short planetary gear (27) meshes with the small sun gear, and the long planetary gear (13) meshes with the large sun gear (31); The short planetary gears (27) are meshed with the long planetary gears (13) and the ring gear (17) respectively.

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