A transmission system using an hmcvt and a control method thereof

Abstract

The present application relates to a kind of vehicle transmission system and its control method, to solve the problems of complex structure, difficult to adapt to complex working condition and poor extensibility existing in existing transmission system, and provide a kind of transmission system using HMCVT and its control method.The transmission system using HMCVT provided by the present application includes double planetary row structure and multiple shaft assembly, the multiple shaft assembly includes parallelly arranged first shaft assembly, second shaft assembly, third shaft assembly, fourth shaft assembly, fifth shaft assembly, output assembly;The double planetary row structure is Ravigneaux type planetary row structure, its first input end, second input end is connected with third shaft, fourth shaft respectively, and its output end is connected with sixth shaft.The present application can realize power uninterrupted transmission and continuously adjustable speed ratio, and can realize whole vehicle ramp hover.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of vehicle transmission system and its control method, specifically relates to a kind of transmission system and its control method using HMCVT. BACKGROUND

[0002] The current agricultural tractor technology level is generally not high, most of the transmission is manual shift product.And in some areas of 180 horsepower above tractor, automatic shift transmission accounts for more than 99%, of which hydraulic continuously variable transmission (referred to as CVT) accounts for more than 54%.CVT leads power shift products in product technology level, driving experience, agricultural operation efficiency.

[0003] The speed ratio of each gear of traditional manual shift and power shift gear transmission is determined, in order to reduce the fuel consumption of engine and reduce the shift impact, the transmission is designed with more and more gears, which makes the transmission structure complex, and there is power interruption in the shift gap, which affects the ability of vehicle to adapt to various complex working conditions.To reduce shift impact and improve the ability of vehicle to adapt to complex working conditions, the traditional transmission system adopts hydraulic torque converter plus parallel shaft gear box structure, but the structure is low in working efficiency when the vehicle is in low speed state.

[0004] Patent CN116557495A discloses a kind of multi-working mode continuously variable transmission system and its use method, first gear is fixedly connected with clutch shaft;Power unit is provided with transmission shaft on both sides;Intermediate shaft is connected with first planetary gear set and second planetary gear set, and constitutes a Ravigneaux planetary gear set;Mode switching assembly can transmit torque on transmission shaft on power unit to intermediate shaft;Brake clutch one end is connected with second planetary gear set, and the other end is fixedly connected with transmission box body;Gear shifting assembly can transmit torque on clutch shaft to intermediate shaft;Planet carrier output gear is connected with Ravigneaux planetary gear set.The invention transmits engine power to Ravigneaux planetary gear set through static hydraulic system and mechanical system, so that the output speed can be continuously increased, and power interruption transmission and continuous adjustable speed ratio can be realized.At the same time, the invention sets mode switching assembly and gear shifting assembly, which can realize multi-mode combination switching.

[0005] But the common problem of the above prior art is that the transmission system structure is complex, difficult to adapt to complex working conditions, and poor in expansibility. SUMMARY

[0006] The purpose of the present application is to solve the problems of complex structure, difficult to adapt to complex working conditions and poor expansibility of existing transmission system, and to provide a kind of transmission system and its control method using HMCVT (Hydro-Mechanical Continuously Variable Transmission, Hydro-Mechanical Continuously Variable Transmission).

[0007] To achieve the above object, the technical solution provided by the application is:

[0008] A transmission system adopting HMCVT, comprising a double planetary gear structure, a plurality of rotating shaft assemblies and a power unit, and characterized in that:

[0009] The double planetary gear structure is a Ravigneaux planetary gear structure; the plurality of rotating shaft assemblies comprise a first shaft assembly, a second shaft assembly, a third shaft assembly, a fourth shaft assembly, a fifth shaft assembly and an output assembly arranged in parallel.

[0010] The first shaft assembly comprises a clutch shaft, a first gear fixed on the clutch shaft, a first-gear clutch, a second-gear clutch and a reverse-gear clutch with their outer rings fixed on the clutch shaft, and a first-gear driving gear, a second-gear driving gear and a reverse-gear driving gear with their inner rings fixed on the clutch shaft and connected with the first-gear clutch, the second-gear clutch and the reverse-gear clutch in sequence through splines.

[0011] The second shaft assembly comprises a power unit shaft, a power unit arranged on the power unit shaft, a second gear fixed on the power unit shaft and engaged with the first gear, and a third gear; the power unit comprises a power input end and a power output end; the second gear is connected with the input end of the power unit, and the third gear is connected with the output end of the power unit.

[0012] The third shaft assembly comprises a first intermediate shaft and a fourth gear fixed on the first intermediate shaft and engaged with the third gear.

[0013] The fourth shaft assembly comprises a hollow shaft sleeved on the first intermediate shaft, a first-gear driven gear and a reverse-gear driven gear fixed on the hollow shaft, and a second-gear / hydraulic-gear driven gear sleeved on the first intermediate shaft; the first-gear driven gear is engaged with the first-gear driving gear, and the reverse-gear driven gear is engaged with the reverse-gear driving gear through a reverse-gear idler.

[0014] The fifth shaft assembly comprises a second intermediate shaft, a hydraulic-gear clutch with its outer ring fixed on the second intermediate shaft, a hydraulic-gear input gear sleeved on the second intermediate shaft and connected with the inner ring of the hydraulic-gear clutch through splines, and a hydraulic-gear output driving gear fixed on the second intermediate shaft and engaged with the second-gear / hydraulic-gear driven gear.

[0015] The output assembly is connected with the output end of the double planetary gear structure and used for power output.

[0016] Furthermore, the output assembly includes a sixth shaft assembly, a power output shaft assembly, a field mode clutch, and a road mode clutch; the sixth shaft assembly includes a sixth shaft connected to the output end of the double planetary gear structure, and a field mode drive gear and a road mode drive gear fixed on the sixth shaft; the power output shaft assembly includes a power output shaft, and a field mode driven gear and a road mode driven gear loosely fitted on the power output shaft; the field mode drive gear meshes with the field mode driven gear, and the road mode drive gear meshes with the road mode driven gear; the outer rings of both the field mode clutch and the road mode clutch are connected to the power output shaft, the inner rings of the field mode clutch are connected to the field mode driven gear, and the inner rings of the road mode clutch are connected to the road mode driven gear.

[0017] Furthermore, the dual planetary gear structure includes a first planetary gear set, a second planetary gear set, a ring gear, and a planet carrier; the planet carrier is the output end of the dual planetary gear set structure; the first planetary gear set includes a first sun gear and multiple first planetary gears meshing with the first sun gear; the first sun gear is the second input end of the dual planetary gear set structure; the second planetary gear set includes a second sun gear and multiple second planetary gears meshing with the second sun gear; the second sun gear is the first input end of the dual planetary gear set structure; the ring gear meshes with the multiple first planetary gears; the ring gear is fixedly connected to a second intermediate shaft; the second planetary gears mesh with the first planetary gears; the multiple first planetary gears are disposed on the outer ring of the planet carrier, and the multiple second planetary gears are disposed on the inner ring of the planet carrier.

[0018] Furthermore, the transmission system using HMCVT also includes a power take-off unit, which includes a power take-off drive gear loosely fitted on the clutch shaft, a power take-off output shaft, a power take-off driven gear fixed on the power take-off output shaft, and a power take-off clutch with its outer ring fixed to the clutch shaft. The power take-off driven gear meshes with the power take-off drive gear, and the power take-off drive gear is fixed to the inner ring of the power take-off clutch.

[0019] Furthermore, the power input end of the power unit is a hydraulic pump; the power output end of the power unit is a hydraulic motor; or, the power input end of the power unit is a generator; the power output end of the power unit is an electric motor.

[0020] Furthermore, the second gear is connected to the first gear, and the third gear is connected to the fourth gear through idler gears.

[0021] Furthermore, this invention also provides a control method for the aforementioned transmission system employing HMCVT, characterized by the following steps:

[0022] Step 1: Select the working area of ​​different working modes, control the engagement state of each clutch, the engine power is input from the clutch shaft, part of the power is transmitted through hydraulic flow, and the other part of the power is transmitted through mechanical flow. After the power is combined through the double planetary gear structure, it is transmitted to the power output shaft for output; the working modes include field mode and road mode; the working areas include pure hydraulic gear working area, forward first gear working area, forward second gear working area and reverse gear working area;

[0023] Field mode:

[0024] Pure hydraulic gear working area: The hydraulic gear clutch and field mode clutch are engaged;

[0025] First gear working area: First gear clutch and field mode clutch are engaged;

[0026] Second gear working zone: Second gear clutch and field mode clutch are engaged;

[0027] Reverse gear working area: The reverse gear clutch and field mode clutch are engaged;

[0028] Road mode:

[0029] Pure hydraulic gear working area: The hydraulic gear clutch and road mode clutch are engaged;

[0030] First gear working area: First gear clutch and road mode clutch are engaged;

[0031] Second gear working zone: Second gear clutch and road mode clutch are engaged;

[0032] Reverse gear working area: Reverse clutch and road mode clutch are engaged;

[0033] Step 2: With the engine speed constant, control the swing angle of the hydraulic pump in the power unit to change continuously or the speed of the generator to change continuously, so as to continuously increase the output shaft speed of the output unit and ultimately realize the continuous adjustment of the transmission system speed ratio.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. The transmission system using HMCVT provided by this invention integrates a double planetary gear structure and multiple shaft assemblies, which can realize uninterrupted power transmission and continuously adjustable speed ratio; by putting the vehicle into pure hydraulic gear and controlling the swing angle of the power unit to zero, the whole vehicle can be hovered on a slope.

[0036] 2. The transmission system using HMCVT provided by the present invention can control the output state of the power take-off by controlling the working state of the power take-off clutch CP, and can realize the output of the power take-off by controlling the engagement of the power take-off clutch.

[0037] 3. The control method of the transmission system using HMCVT provided by the present invention is divided into field mode and road mode. The working range of field mode meets the actual agricultural needs speed, and the vehicle speed of road mode can be expanded according to user needs. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the transmission system embodiment of the present invention using HMCVT;

[0039] Figure 2 This is a schematic diagram of the double planetary gear structure in an embodiment of the present invention;

[0040] Explanation of reference numerals in the attached figures:

[0041] S1 - Clutch shaft; S2 - Power unit shaft; S3 - First intermediate shaft; S4 - Hollow shaft; S5 - Second intermediate shaft; S6 - Sixth shaft; S7 - Power output shaft; S8 - Power take-off output shaft;

[0042] G1 - First gear; G2 - Second gear; G3 - Third gear; G4 - Fourth gear; G5 - Hydraulic gear input gear; G6 - Hydraulic gear output drive gear; G7 - Reverse gear drive gear; G8 - Reverse gear idler gear; G9 - Reverse gear driven gear; G10 - First gear drive gear; G11 - First gear driven gear; G12 - Second gear drive gear; G13 - Second gear / hydraulic gear driven gear; G14 - Field mode drive gear; G15 - Field mode driven gear; G16 - Road mode drive gear; G17 - Road mode driven gear; G18 - Power take-off drive gear; G19 - Power take-off driven gear.

[0043] H-Power unit;

[0044] C1 - First gear clutch, C2 - Second gear clutch, CR - Reverse gear clutch, CHY - Hydraulic gear clutch, CL - Field mode clutch; CH - Road mode clutch; CP - Power take-off clutch;

[0045] P1 - First planetary gear set; P2 - Second planetary gear set; P10 - First sun gear; P11 - Ring gear; P12 - First planetary gear; P13 - Planet carrier; P20 - Second sun gear; P21 - Second planetary gear. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0047] A drive system employing HMCVT, see [link / reference] Figure 1 and Figure 2 It includes a double planetary gear structure, multiple rotating shaft assemblies, and a power unit H;

[0048] The dual planetary gear structure is a Ravina-type planetary gear structure; multiple rotating shaft assemblies include a first shaft assembly, a second shaft assembly, a third shaft assembly, a fourth shaft assembly, a fifth shaft assembly, an output assembly, and a power take-off unit arranged in parallel;

[0049] The first shaft assembly includes a clutch shaft S1, a first gear G1 fixed on the clutch shaft S1, a first gear clutch C1, a second gear clutch C2, and a reverse gear clutch CR whose outer rings are respectively fixed on the clutch shaft S1, and a first gear drive gear G10, a second gear drive gear G12, and a reverse gear drive gear G7 that are loosely fitted on the clutch shaft S1 and sequentially connected to the inner rings of the first gear clutch C1, the second gear clutch C2, and the reverse gear clutch CR via splines.

[0050] The second shaft assembly includes a power unit shaft S2, a power unit H mounted on the power unit shaft S2, a second gear G2 fixed on the power unit shaft S2 and meshing with the first gear G1, and a third gear G3; the power unit H includes a power input end and a power output end; the second gear G2 is connected to the input end of the power unit H, and the third gear G3 is connected to the output end of the power unit H;

[0051] The third shaft assembly includes a first intermediate shaft S3 and a fourth gear G4 fixed on the first intermediate shaft S3 and meshing with the third gear G3.

[0052] The fourth shaft assembly includes a hollow shaft S4 loosely fitted on the first intermediate shaft S3, a first gear driven gear G11 and a reverse gear driven wheel G9 fixed on the hollow shaft S4, and a second gear / hydraulic gear driven gear G13 loosely fitted on the first intermediate shaft S3; the first gear driven gear G11 meshes with the first gear driving gear G10, and the reverse gear driven wheel G9 meshes with the reverse gear driving gear G7 through the reverse idler wheel G8;

[0053] The fifth shaft assembly includes a second intermediate shaft S5, a hydraulic gear clutch CHY whose outer ring is fixedly connected to the second intermediate shaft S5, a hydraulic gear input gear G5 that is loosely fitted on the second intermediate shaft S5 and connected to the inner ring of the hydraulic gear clutch CHY via a spline, and a hydraulic gear output drive gear G6 that is fixedly mounted on the second intermediate shaft S5 and meshes with the second gear / hydraulic gear driven gear G13.

[0054] The output assembly is connected to the output end of the dual planetary gear structure for power output, including the sixth shaft assembly, power output shaft assembly, field mode clutch CL and road mode clutch CH;

[0055] The sixth shaft assembly includes a sixth shaft S6 connected to the output end of the dual planetary gear structure, and a field mode drive gear G14 and a road mode drive gear G16 fixed on the sixth shaft S6.

[0056] The power output shaft assembly includes a power output shaft S7, and a field mode passive gear G15 and a road mode passive gear G17 loosely fitted on the power output shaft S7; the field mode drive gear G14 meshes with the field mode passive gear G15, and the road mode drive gear G16 meshes with the road mode passive gear G17.

[0057] The outer rings of both the field mode clutch CL and the road mode clutch CH are connected to the power output shaft S7. The inner ring of the field mode clutch CL is connected to the field mode driven gear G15, and the inner ring of the road mode clutch CH is connected to the road mode driven gear G17.

[0058] In this embodiment, the dual planetary gear set structure includes a first planetary gear set P1, a second planetary gear set P2, a ring gear P11, and a planet carrier P13; the planet carrier P13 is the output end of the dual planetary gear set structure; the first planetary gear set P1 includes a first sun gear P10 and a plurality of first planet gears P12 meshing with the first sun gear P10; the first sun gear P10 is the second input end of the dual planetary gear set structure; the second planetary gear set P2 includes a second sun gear P20 and a plurality of second planet gears P21 meshing with the second sun gear P20; the second sun gear P20 is the first input end of the dual planetary gear set structure; the ring gear P11 meshes with the plurality of first planet gears P12; the ring gear P11 is fixedly connected to the second intermediate shaft S5; the second planet gears P21 mesh with the first planet gears P12; the plurality of first planet gears P12 are disposed on the outer ring of the planet carrier P13, and the plurality of second planet gears P21 are disposed on the inner ring of the planet carrier P13.

[0059] The power take-off unit includes a power take-off drive gear G18 loosely fitted on the clutch shaft S1, a power take-off output shaft S8, a power take-off driven gear G19 fixed on the power take-off output shaft S8, and a power take-off clutch CP with its outer ring fixed to the clutch shaft S1. The power take-off driven gear G19 meshes with the power take-off drive gear G18, and the power take-off drive gear G18 is fixed to the inner ring of the power take-off clutch CP.

[0060] Specifically, the power input end of the power unit H is a hydraulic pump; the power output end of the power unit H is a hydraulic motor; or, the power input end of the power unit H is a generator; the power output end of the power unit H is an electric motor.

[0061] This embodiment also provides a control method for the aforementioned transmission system employing HMCVT, characterized by comprising the following steps:

[0062] Step 1: Select the working area of ​​different working modes and control the engagement state of each clutch. The engine power is input from the clutch shaft S1. Part of the power is transmitted through hydraulic flow and the other part is transmitted through mechanical flow. After the power is combined through the double planetary gear structure, it is transmitted to the power output shaft S7 for output. The working modes include field mode and road mode. The working areas include pure hydraulic gear working area, forward first gear working area, forward second gear working area and reverse gear working area.

[0063] Field mode:

[0064] In the pure hydraulic gear working area: the hydraulic gear clutch CHY and the field mode clutch CL are engaged;

[0065] First gear working area: First gear clutch C1 and field mode clutch CL are engaged;

[0066] Second gear working zone: Second gear clutch C2 and field mode clutch CL are engaged;

[0067] Reverse gear working area: Reverse clutch CR and field mode clutch CL are engaged;

[0068] Road mode:

[0069] Pure hydraulic gear working area: Hydraulic gear clutch CHY and road mode clutch CH are engaged;

[0070] First gear working area: First gear clutch C1 and road mode clutch CH are engaged;

[0071] Second gear working area: Second gear clutch C2 and road mode clutch CH are engaged;

[0072] Reverse gear working area: Reverse clutch CR and road mode clutch CH are engaged;

[0073] Step 2: With the engine speed constant, continuously change the swing angle of the hydraulic pump in power unit H or continuously change the speed of the generator to continuously increase the output shaft speed of the output unit, ultimately achieving continuous adjustment of the transmission system speed ratio.

[0074] Combined with appendix Figure 1 Further explanation of the power transmission routes in different working areas of the present invention:

[0075] In the pure hydraulic gear operating area of ​​the field mode: engine power is input from the clutch shaft S1 and reaches the first gear G1; at this time, all power is transmitted through hydraulic flow: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence; at this time, the hydraulic power is divided into two paths at the fourth gear G4. The first path: the fourth gear G4 drives the hydraulic gear input gear G5, the hydraulic gear clutch CHY, the intermediate shaft S5, the hydraulic gear output drive gear G6, and the second gear / hydraulic gear driven gear G13 in sequence, reaching the ring gear P11 of the second planetary gear set P2; the second path: the fourth gear G4 drives the second sun gear P20, and after converging in the second planetary gear set P2, it is output through the planet carrier P13. Then, the planet carrier output shaft S6 drives the field mode drive gear G14 and the field mode driven gear G15 in sequence, finally reaching the power output shaft S7.

[0076] In this working area, with the engine speed constant, the speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H1 to continuously change from the positive maximum to the negative maximum, and the speed ratio is continuously adjustable.

[0077] In the field mode, in the first gear working range: engine power is input from the clutch shaft S1 and reaches the first gear G1; at this time, part of the power is transmitted through hydraulic flow: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence, reaching the sun gear of the second planetary gear set P2; the other part of the power is transmitted through mechanical flow: the first gear drive gear G10 drives the first gear driven gear G11, reaching the sun gear of the first planetary gear set P1; the two power paths converge in the double planetary gear set structure and are output through the planet carrier P13, and then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 drives the field mode drive gear G14 and the field mode driven gear G15 in sequence, finally reaching the power output shaft S7.

[0078] In this working range, with the engine speed remaining constant, the rotational speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H1 to continuously change from the negative maximum to the positive maximum, and the speed ratio is continuously adjustable.

[0079] In the field mode forward second gear operating range: Engine power is input from the clutch shaft S1 and reaches the first gear G1. At this time, part of the power is transmitted hydraulically: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence, reaching the second sun gear P20; the other part of the power is transmitted mechanically: the first gear G1 drives the second gear drive gear G12 and the second gear / hydraulic gear driven gear G13 in sequence, reaching the ring gear of the first planetary gear set P1; the two power paths converge in the double planetary gear set structure and are output through the planet carrier, and then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 drives the field mode drive gear G14 and the field mode driven gear G15 in sequence, finally reaching the power output shaft S7.

[0080] In this working area, with the engine speed constant, the speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H to continuously change from the positive maximum to the negative maximum, and the speed ratio is continuously adjustable.

[0081] In the reverse field mode operating area: Engine power is input from the clutch shaft S1 and reaches the first gear G1. At this time, part of the power is transmitted hydraulically: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence, reaching the sun gear of the second planetary gear set P2; the other part of the power is transmitted mechanically: the first gear G1 drives the reverse drive gear G7, the reverse idler gear G8, and the reverse driven gear G9 in sequence, reaching the sun gear of the first planetary gear set P1; the two power paths converge in the double planetary gear set structure and are output through the planet carrier P13, and then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 drives the field mode drive gear G14 and the field mode driven gear G15 in sequence, finally reaching the power output shaft S7.

[0082] In this working area, with the engine speed constant, by controlling the swing angle of the variable pump in the power unit H to continuously change from the positive maximum to the negative maximum, the speed of the power output shaft S7 continuously increases in the opposite direction to the forward gear speed, and the speed ratio is continuously adjustable.

[0083] In the pure hydraulic gear operating area of ​​road mode: Engine power is input from the clutch shaft S1 and reaches the first gear G1. All power is transmitted through hydraulic flow: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence; at this time, the hydraulic power is divided into two paths at the fourth gear G4. The first path: the fourth gear G4 drives the hydraulic gear input gear G5, the hydraulic gear clutch CHY, the intermediate shaft S5, the hydraulic gear output drive gear G6, and the second gear / hydraulic gear driven gear G13 in sequence, reaching the P2 planetary gear ring; the second path: the fourth gear G4 drives the second sun gear P20; after converging at the second planetary gear ring P2, it is output through the planet carrier P13: the planet carrier output shaft S6 drives the road mode drive gear G16 and the road mode driven gear G17 in sequence, finally reaching the power output shaft S7;

[0084] In this working area, with the engine speed constant, the speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H1 to continuously change from the positive maximum to the negative maximum, and the speed ratio is continuously adjustable.

[0085] In the first gear operating range of road mode: Engine power is input from the clutch shaft S1 and reaches the first gear G1. At this time, part of the power is transmitted hydraulically: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence, reaching the second sun gear P20; the other part of the power is transmitted mechanically: the first gear drive gear G10 drives the first gear driven gear G11, reaching the first sun gear P10. The two power paths converge in the double planetary gear structure and are output through the planet carrier P13, and then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 drives the road mode drive gear G16 and the road mode driven gear G17 in sequence, finally reaching the power output shaft S7.

[0086] In this working range, with the engine speed remaining constant, the rotational speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H1 to continuously change from the negative maximum to the positive maximum, and the speed ratio is continuously adjustable.

[0087] In the second gear operating range of road mode: Engine power is input from the clutch shaft S1 and reaches the first gear G1. At this time, part of the power is transmitted hydraulically: the first gear G1 drives the second gear G2, the third gear G3, and the fourth gear G4 in sequence, reaching the second sun gear P20; the other part of the power is transmitted mechanically: the first gear G1 drives the second gear drive gear G12 and the second gear / hydraulic gear driven gear G13 in sequence, reaching the ring gear of the first planetary gear set P1. The two power paths converge in the double planetary gear set structure and are output through the planet carrier P13, and then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 drives the road mode drive gear G16 and the road mode driven gear G17 in sequence, finally reaching the power output shaft S7.

[0088] In this working area, with the engine speed constant, the speed of the power output shaft S7 is continuously increased by controlling the swing angle of the variable pump in the power unit H to continuously change from the positive maximum to the negative maximum, and the speed ratio is continuously adjustable.

[0089] In the reverse gear operating range of road mode: Engine power is input from the clutch shaft S1 and reaches the first gear G1. At this point, part of the power is transmitted hydraulically: the first gear G1 sequentially drives the second gear G2, the third gear G3, and the fourth gear G4, reaching the sun gear of the second planetary gear set P2; the other part of the power is transmitted mechanically: the first gear G1 sequentially drives the reverse drive gear G7, the reverse idler gear G8, and the reverse driven gear G9, reaching the sun gear of the first planetary gear set P1. The two power paths converge in the dual planetary gear set structure and are output through the planet carrier P13, then transmitted to the planet carrier output shaft S6. The planet carrier output shaft S6 sequentially drives the road mode drive gear G16 and the road mode driven gear G17, finally reaching the power output shaft S7.

[0090] In this working range, with the engine speed constant, the rotational speed of the power output shaft S7 is continuously increased (opposite to the forward gear speed) by controlling the swing angle of the variable pump in the power unit H to continuously change from the positive maximum to the negative maximum, and the speed ratio is continuously adjustable.

[0091] Table 1 below lists the working status of the clutch in each of the above working areas. Cells marked with "●" in Table 1 indicate that the corresponding clutch is engaged, and cells without "●" indicate that the corresponding clutch is disengaged.

[0092] Table 1. Clutch operating status in different operating zones of a transmission system using HMCVT.

[0093]

[0094]

[0095] In the table above, C1, C2, CR, CHY, CL, and CH represent, respectively, the first gear clutch, the second gear clutch, the reverse gear clutch, the hydraulic gear clutch, the field mode clutch, and the road mode clutch.

[0096] It should be noted that the above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A transmission system employing HMCVT, comprising a double planetary gear set structure, multiple shaft assemblies, and a power unit (H), characterized in that: The dual planetary gear structure is a Ravina-type planetary gear structure; the multiple rotating shaft assemblies include a first shaft assembly, a second shaft assembly, a third shaft assembly, a fourth shaft assembly, a fifth shaft assembly, and an output assembly arranged in parallel. The first shaft assembly includes a clutch shaft (S1), a first gear (G1) fixed on the clutch shaft (S1), a first gear clutch (C1), a second gear clutch (C2), and a reverse gear clutch (CR) whose outer rings are respectively fixed on the clutch shaft (S1), and a first gear drive gear (G10), a second gear drive gear (G12), and a reverse gear drive gear (G7) that are loosely fitted on the clutch shaft (S1) and sequentially connected to the inner rings of the first gear clutch (C1), the second gear clutch (C2), and the reverse gear clutch (CR) through splines. The second shaft assembly includes a power unit shaft (S2), a power unit (H) mounted on the power unit shaft (S2), a second gear (G2) fixed on the power unit shaft (S2) and meshing with the first gear (G1), and a third gear (G3); the power unit (H) includes a power input end and a power output end; the second gear (G2) is connected to the input end of the power unit (H), and the third gear (G3) is connected to the output end of the power unit (H); The third shaft assembly includes a first intermediate shaft (S3) and a fourth gear (G4) fixed on the first intermediate shaft (S3) and meshing with the third gear (G3). The fourth shaft assembly includes a hollow shaft (S4) loosely fitted on the first intermediate shaft (S3), a first-gear driven gear (G11) and a reverse-gear driven wheel (G9) fixed on the hollow shaft (S4), and a second-gear / hydraulic-gear driven gear (G13) loosely fitted on the first intermediate shaft (S3); the first-gear driven gear (G11) meshes with the first-gear driving gear (G10), and the reverse-gear driven wheel (G9) meshes with the reverse-gear driving gear (G7) through the reverse idler wheel (G8); The fifth shaft assembly includes a second intermediate shaft (S5), a hydraulic gear clutch (CHY) whose outer ring is fixedly connected to the second intermediate shaft (S5), a hydraulic gear input gear (G5) that is loosely fitted on the second intermediate shaft (S5) and connected to the inner ring of the hydraulic gear clutch (CHY) via a spline, and a hydraulic gear output drive gear (G6) that is fixedly mounted on the second intermediate shaft (S5) and meshes with the second gear / hydraulic gear driven gear (G13). The output component is connected to the output end of the dual planetary gear structure for power output; The output components include a sixth shaft assembly, a power take-off shaft assembly, a field mode clutch (CL), and a road mode clutch (CH); The sixth shaft assembly includes a sixth shaft (S6) connected to the output end of the double planetary gear structure, and a field mode drive gear (G14) and a road mode drive gear (G16) fixed on the sixth shaft (S6). The power output shaft assembly includes a power output shaft (S7), and a field mode passive gear (G15) and a road mode passive gear (G17) loosely fitted on the power output shaft (S7); the field mode drive gear (G14) meshes with the field mode passive gear (G15), and the road mode drive gear (G16) meshes with the road mode passive gear (G17). The outer rings of the field mode clutch (CL) and the road mode clutch (CH) are both connected to the power output shaft (S7), the inner ring of the field mode clutch (CL) is connected to the field mode driven gear (G15), and the inner ring of the road mode clutch (CH) is connected to the road mode driven gear (G17). The gear ring (P11) of the double planetary gear structure is fixedly connected to the second intermediate shaft (S5).

2. The transmission system employing HMCVT according to claim 1, characterized in that: The dual planetary gear structure includes a first planetary gear (P1), a second planetary gear (P2), a gear ring (P11), and a planet carrier (P13); the planet carrier (P13) is the output end of the dual planetary gear structure. The first planetary gear set (P1) includes a first sun gear (P10) and multiple first planet gears (P12) meshing with the first sun gear (P10); the first sun gear (P10) is the second input end of the double planetary gear set structure; the second planetary gear set (P2) includes a second sun gear (P20) and multiple second planet gears (P21) meshing with the second sun gear (P20); the second sun gear (P20) is the first input end of the double planetary gear set structure; the ring gear (P11) meshes with the multiple first planet gears (P12); the second planet gears (P21) mesh with the first planet gears (P12); the multiple first planet gears (P12) are arranged on the outer ring of the planet carrier (P13), and the multiple second planet gears (P21) are arranged on the inner ring of the planet carrier (P13).

3. The transmission system employing HMCVT according to claim 2, characterized in that: It also includes a power take-off unit, which includes a power take-off drive gear (G18) loosely fitted on the clutch shaft (S1), a power take-off output shaft (S8), a power take-off driven gear (G19) fixed on the power take-off output shaft (S8), and a power take-off clutch (CP) with its outer ring fixed to the clutch shaft (S1). The power take-off driven gear (G19) meshes with the power take-off drive gear (G18), and the power take-off drive gear (G18) is fixed to the inner ring of the power take-off clutch (CP).

4. The transmission system employing HMCVT according to claim 3, characterized in that: The power input terminal of the power unit (H) is a hydraulic pump; the power output terminal of the power unit (H) is a hydraulic motor; or, the power input terminal of the power unit (H) is a generator; the power output terminal of the power unit (H) is an electric motor.

5. The transmission system employing HMCVT according to claim 4, characterized in that: The second gear (G2) is connected to the first gear (G1), and the third gear (G3) is connected to the fourth gear (G4) through idler gears.

6. A control method for a transmission system employing HMCVT as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Select the working area of ​​different working modes, control the engagement state of each clutch, the engine power is input from the clutch shaft (S1), part of the power is transmitted through hydraulic flow, and the other part of the power is transmitted through mechanical flow. After the power is combined through the double planetary gear structure, it is transmitted to the power output shaft (S7) for output; the working modes include field mode and road mode; the working areas include pure hydraulic gear working area, forward first gear working area, forward second gear working area and reverse gear working area; Field mode: Pure hydraulic gear operating area: Hydraulic gear clutch (CHY) and field mode clutch (CL) are engaged; First gear working area: First gear clutch (C1) and field mode clutch (CL) are engaged; Second gear working zone: Second gear clutch (C2) and field mode clutch (CL) are engaged; Reverse gear working area: Reverse clutch (CR) and field mode clutch (CL) are engaged; Road mode: Pure hydraulic gear operating area: Hydraulic gear clutch (CHY) and road mode clutch (CH) are engaged; First gear working area: First gear clutch (C1) and road mode clutch (CH) are engaged; Second gear operating range: Second gear clutch (C2) and road mode clutch (CH) are engaged; Reverse gear operating zone: Reverse clutch (CR) and road mode clutch (CH) are engaged; Step 2: With the engine speed constant, control the swing angle of the hydraulic pump in the power unit (H) to change continuously or the speed of the generator to change continuously, so as to continuously increase the output shaft speed of the output unit and ultimately realize the continuous adjustment of the transmission system speed ratio.

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