阅读说明：本技术 一种多功率分配模式的机械液压复合传动装置及控制方法 (Multi-power distribution mode mechanical-hydraulic composite transmission device and control method ) 是由 朱镇 蔡英凤 陈龙 夏长高 田翔 韩江义 孙晓东 施德华 王峰 袁朝春 于 2019-10-08 设计创作，主要内容包括：本发明公开了一种多功率分配模式的机械液压复合传动装置,包括输入轴、分流机构、机械传动组件、液压传动组件和输出轴,所述输入轴通过分流机构与相互并联的机械传动组件和液压传动组件连接,所述机械传动组件和液压传动组件同时与输出轴连接；通过换挡元件之间的组合切换实现纯液压传动、机械液压复合传动和纯机械传动三种类型的传动。有益效果：本发明有多个档位可供选择,能够根据复杂的作业工况提供多种功率分配模式,充分利用机械传动的传动性能和液压传动的无级调速性能,有利于提高车辆的作业效率、动力性和经济性。机械档换挡装置采用单向离合器既能实现发动机制动,又能均匀使用各换挡元件以增加使用寿命。(The invention discloses a multi-power distribution mode mechanical hydraulic composite transmission device, which comprises an input shaft, a shunt mechanism, a mechanical transmission assembly, a hydraulic transmission assembly and an output shaft, wherein the input shaft is connected with the mechanical transmission assembly and the hydraulic transmission assembly which are mutually connected in parallel through the shunt mechanism; the three types of transmission, namely pure hydraulic transmission, mechanical hydraulic composite transmission and pure mechanical transmission, are realized through the combined switching among the gear shifting elements. Has the advantages that: the invention has a plurality of gears to be selected, can provide a plurality of power distribution modes according to complex operation conditions, fully utilizes the transmission performance of mechanical transmission and the stepless speed regulation performance of hydraulic transmission, and is beneficial to improving the operation efficiency, the dynamic property and the economical efficiency of vehicles. The mechanical gear shifting device adopts the one-way clutch, so that the engine can be braked, and all shifting elements can be uniformly used to prolong the service life.)

1. A multi-power distribution mode mechanical hydraulic composite transmission device comprises an input shaft (1), a shunt mechanism (2), a mechanical transmission assembly (3), a hydraulic transmission assembly (4) and an output shaft (5), wherein the input shaft (1) is connected with the mechanical transmission assembly (3) and the hydraulic transmission assembly (4) which are connected in parallel through the shunt mechanism (2), and the mechanical transmission assembly (3) and the hydraulic transmission assembly (4) are simultaneously connected with the output shaft (5); the method is characterized in that: the mechanical transmission assembly (3) comprises a front planet row assembly (31) and a rear planet row assembly (32) which are connected in series;

the front planet row component (31) comprises a first clutch (311), a second clutch (312), a third clutch (313), a front planet row gear ring (314), a front planet row planet carrier (315), a front planet row sun gear (316) and a first one-way clutch (317), the first clutch (311) is positioned between the shunting mechanism (2) and the front planet row gear ring (314), the second clutch (312) and the third clutch (313) are mutually connected in parallel and are respectively connected with the front planet row sun gear (316), the first one-way clutch (317) is arranged between the third clutch (313) and the front planet row sun gear (316), and the output shaft (5) is connected with the front planet row planet carrier (315);

the rear planet row assembly (32) comprises a fourth clutch (321), a rear planet row sun gear (322), a rear planet row planet carrier (323), a rear planet row ring gear (324), a first brake (325), a second brake (326) and a second one-way clutch (327), wherein the fourth clutch (321) is positioned between the shunting mechanism (2) and the rear planet row sun gear (322), the first brake (325) is connected with the rear planet row sun gear (322), the rear planet row planet carrier (323) is connected with a front planet row ring gear (314) and connected with the second brake (326) and the second one-way clutch (327) which are connected in parallel, and the rear planet row ring gear (324) is connected with an output shaft (5).

2. The multi-power split mode mechano-hydraulic compound transmission of claim 1, wherein: the hydraulic transmission assembly (4) comprises a hydraulic transmission input clutch (41), a hydraulic transmission input gear pair (42), a hydraulic pump (43), a hydraulic oil pipe (44), a hydraulic motor (45), a hydraulic transmission output gear pair (46) and a hydraulic transmission output clutch (47); the hydraulic pump (43) is connected with the shunting mechanism (2) through a hydraulic transmission input gear pair (42), a hydraulic transmission input clutch (41) is arranged between the hydraulic transmission input gear pair (42) and the hydraulic pump (43), the hydraulic pump (43) is connected with a hydraulic motor (45) through a hydraulic oil pipe (44), the hydraulic motor (45) is connected with an output shaft (5) through a hydraulic transmission output gear pair (46), and the hydraulic motor (45) is provided with a hydraulic transmission output clutch (47) through the hydraulic transmission output gear pair (46).

3. The multi-power split mode mechano-hydraulic compound transmission of claim 1 or 2, wherein: the shunting mechanism (2) comprises a shunting brake (21), a shunting mechanism sun gear (22), a shunting mechanism planet carrier (23) and a shunting mechanism gear ring (24); input shaft (1) is connected with reposition of redundant personnel mechanism ring gear (24), reposition of redundant personnel mechanism sun gear (22) are connected with hydraulic transmission subassembly (4), be equipped with reposition of redundant personnel stopper (21) on reposition of redundant personnel mechanism sun gear (22), reposition of redundant personnel mechanism planet carrier (23) are connected with mechanical transmission subassembly (3).

4. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 3, wherein: the three types of transmission, namely pure hydraulic transmission, mechanical hydraulic composite transmission and pure mechanical transmission, are realized through the combined switching between the brake and the clutch, and the specific transmission types are as follows:

pure hydraulic transmission: the first brake (325), the hydraulic transmission input clutch (41), the hydraulic transmission output clutch (47) and the fourth clutch (321) are engaged, the other clutches and the brake are separated, the fourth clutch (321) is connected with the first brake (325), the planet carrier (23) of the shunting mechanism is braked, the hydraulic transmission input clutch (41) is connected with the hydraulic transmission output clutch (47), the power drives the hydraulic pump (43) to work through the input shaft (1), the gear ring (24) of the shunting mechanism, the sun gear (22) of the shunting mechanism, the hydraulic transmission input gear pair (42) and the input clutch (41), the hydraulic pump (43) converts mechanical power into high-pressure oil and drives a hydraulic motor (45) to work through a hydraulic pipeline (44), and the mechanical power output by the hydraulic motor (45) is transmitted to the output shaft (5) through a hydraulic transmission output clutch (47) and a hydraulic transmission output gear pair (46);

pure mechanical transmission: the hydraulic transmission system comprises a hydraulic transmission input clutch (41), a hydraulic transmission output clutch (47), a second brake (326) and a fourth clutch (321), wherein the shunt brake (21) is connected, the gears with different transmission speed ratios in a pure mechanical transmission mode are switched through the combination of other clutches and brakes, the shunt brake (21) is connected, the hydraulic transmission input clutch (41) is separated from the hydraulic transmission output clutch (47), a hydraulic transmission assembly (4) is in unpowered input, power is transmitted to a mechanical transmission assembly (3) through an input shaft (1), a shunt mechanism gear ring (24) and a shunt mechanism planet carrier (23), and the mechanical transmission assembly (3) is output from an output shaft (5) after speed ratio adjustment;

mechanical hydraulic composite transmission: the hydraulic transmission input clutch (41) is connected with the hydraulic transmission output clutch (47), the shunt brake (21), the third clutch (313), the first one-way clutch (317) and the second one-way clutch (327) are separated, the gears with different transmission speed ratios in a mechanical hydraulic composite transmission mode are switched through the combination of other clutches and the brake, power is shunted at the position of the shunt mechanism planet carrier (23) through the input shaft (1) and the shunt mechanism gear ring (24) to the shunt mechanism planet carrier (23), flows to the mechanical transmission assembly (3) and the shunt mechanism sun gear (22) respectively, and the shunt mechanism sun gear (22) is connected with the hydraulic transmission assembly (4) and finally converges to the output shaft (5) for output.

5. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 4, wherein: the pure mechanical transmission mode comprises a mechanical transmission I gear, a mechanical transmission II gear, a mechanical transmission III gear and a mechanical transmission IV gear, and the specific implementation method comprises the following steps:

mechanical transmission I gear: the first brake (325), the first clutch (311) and the second clutch (312) are separated, the third clutch (313), the first one-way clutch (317) and the second one-way clutch (327) are connected, and power sequentially passes through the third clutch (313), the first one-way clutch (317) and the front planet row sun gear (316) from the planet carrier (23) of the shunting mechanism to the output shaft (5);

mechanical transmission II: the power split type planetary gear set comprises a first brake (325), a first clutch (311), a second clutch (312) and a second one-way clutch (327), wherein the third clutch (313) and the first one-way clutch (317) are separated, the power sequentially passes through the third clutch (313), the first one-way clutch (317) and a front planet row sun gear (316) from a split mechanism planet carrier (23) to the front planet row planet carrier (315), the power at the front planet row planet carrier (315) is respectively split to an output shaft (5) and a front planet row gear ring (314), the power of the front planet row gear ring (314) is sequentially transmitted to a rear planet row planet carrier (323) and a rear planet row gear ring (324), and finally is converged to the output shaft (5);

mechanical transmission III gear: the first brake (325), the second clutch (312) and the second one-way clutch (327) are separated, the first clutch (311), the third clutch (313) and the first one-way clutch (317) are connected, power is input from the planet carrier (23) of the split mechanism to the first clutch (311) to be split, flows to the front planet row ring gear (314) and the front planet row sun gear (316) to converge at the front planet row planet carrier (315) respectively, and is finally output from the output shaft (5);

mechanical transmission IV gear: the second clutch (312), the third clutch (313), the first one-way clutch (317) and the second one-way clutch (327) are separated, the first clutch (311) and the first brake (325) are connected, and power is output from the split mechanism planet carrier (23) to the output shaft (5) through the first clutch (311), the front planet row gear ring (314), the rear planet row planet carrier (323) and the rear planet row gear ring (324) in sequence.

6. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 4, wherein: the mechanical hydraulic composite transmission mode comprises a composite transmission I gear, a composite transmission II gear, a composite transmission III gear and a composite transmission IV gear, and the specific implementation method comprises the following steps:

compound transmission I gear: the first brake (325), the first clutch (311) and the fourth clutch (321) are separated, the second brake (326) and the second clutch (312) are connected, power is split from the split mechanism gear ring (24) from the split mechanism planet carrier (23), one part of power flows to the hydraulic transmission assembly (4) from the split mechanism planet carrier (23) through the split mechanism sun gear (22), the other part of power flows to the hydraulic transmission assembly (4) from the split mechanism planet carrier (23) sequentially through the second clutch (312), the front planet row sun gear (316) and the front planet row planet carrier (315), and finally the power is converged to the output shaft (5) for output;

compound transmission II: the second brake (326), the first clutch (311) and the fourth clutch (321) are separated, the first brake (325) and the second clutch (312) are connected, power is split from the split mechanism gear ring (24) from the split mechanism planet carrier (23), one part of power flows to the hydraulic transmission assembly (4) from the split mechanism planet carrier (23) through the split mechanism sun gear (22), the other part of power flows to the front planet row planet carrier (315) from the split mechanism planet carrier (23) sequentially through the second clutch (312) and the front planet row sun gear (316), and the power at the front planet row planet carrier (315) is respectively split to the output shaft (5) and the front planet row gear ring (314), the power of the front planet row gear ring (314) is sequentially transmitted to the rear planet row planet carrier (323) and the rear planet row gear ring (324), and the three groups of split power are finally converged to the output shaft (5);

compound transmission III: the first brake (325), the second brake (326) and the fourth clutch (321) are separated, the first clutch (311) and the second clutch (312) are connected, power is split from the split mechanism gear ring (24) from the split mechanism planet carrier (23), one part of power flows to the hydraulic transmission assembly (4) from the split mechanism planet carrier (23) through the split mechanism sun gear (22), the other part of power is split from the split mechanism planet carrier (23) to the second clutch (312) and flows to the front planet row gear ring (314) and the front planet row sun gear (316) to be converged on the front planet row planet carrier (315), and the mechanical transmission assembly (3) and the hydraulic transmission assembly (4) are converged and output on the output shaft (5);

compound transmission IV gear: the first brake (325), the first clutch (311) and the second clutch (312) are separated, the second brake (326) and the fourth clutch (321) are connected, power is split from the splitting mechanism gear ring (24) from the splitting mechanism planet carrier (23), one part of power flows to the hydraulic transmission assembly (4) from the splitting mechanism planet carrier (23) through the splitting mechanism sun gear (22), the other part of power flows to the output shaft (5) from the splitting mechanism planet carrier (23) sequentially through the fourth clutch (321), the rear planet row sun gear (322) and the rear planet row gear ring (324), and the mechanical transmission assembly (3) and the hydraulic transmission assembly (4) are converged and output on the output shaft (5).

7. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 6, wherein: when the gears of the mechanical hydraulic compound transmission mode are switched, a compound transmission I gear → a compound transmission II gear relates to 2 shifting elements, a compound transmission II gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission III gear → a compound transmission IV gear relates to 4 shifting elements, a compound transmission I gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission I gear → a compound transmission IV gear relates to 2 shifting elements, and a compound transmission II gear → a compound transmission IV gear relates to 4 shifting elements;

gear shifts involving 2 and less shift elements can give an optimum solution by not more than 3 trials; the gear shifts involving 3 or 4 shift elements and no interaction are analyzed by an orthogonal table; gear shifting involving 4 shift elements makes full use of 4 columns of the orthogonal table, and gear shifting involving 3 shift elements selects any 3 columns of the orthogonal table;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing interactive orthogonal analysis; test data are obtained through tests; determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, comparing the dispersion square sum and the degree of freedom with a critical value, and determining the significance of the factors and the errors; obtaining the optimal scheme of each evaluation index, and determining the optimal scheme according to the weight coefficient; and controlling the switching time sequence of each group of gear shifting elements in groups according to the gear shifting mechanism switching time sequence data obtained under different working conditions.

8. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 7, wherein: the control method for gear switching of the mechanical hydraulic compound transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

the output shaft angular velocity variation is defined as:

where α is the output shaft angular velocity variation,

the output shaft angular velocity change rate is defined as:

β is the change rate of the angular speed of the output shaft;

the torque of the output shaft is:

T_o＝β·J_o

in the formula T_oFor output shaft torque, J_oIs the rotational inertia of the output shaft;

the second derivative of the angular velocity of the output shaft is:

in the formula, gamma is the second differential of the angular velocity of the output shaft;

the jerk is the rate of change of the vehicle longitudinal acceleration:

wherein j is the impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) establishing L as shown in Table 2₉(3⁴) An orthogonal table; in the table, "1", "2" and "3" are three levels, representing the relevant shifting elements "advanced", "on time" and "delayed" shift, respectively; "a", "b", "c" and "d" are four factors, respectively representing non-interacting shifting elements; n is the total number of tests, n is 9,

TABLE 2 orthogonal table for mechanical hydraulic compound transmission mode element switching time sequence

a b c d Test results x_i 1 2 3 4 1 1 1 1 1 2 1 2 2 2 3 1 3 3 3 4 2 1 2 3 5 2 2 3 1 6 2 3 1 2 7 3 1 3 2 8 3 2 1 3 9 3 3 2 1

The symbols in the table are expressed as follows:

extremely poor:

determining the primary and secondary sequence of each factor through range data, determining the optimal scheme of a single evaluation index, and finally determining the optimal scheme according to the weight coefficient;

and (3) determining an optimal scheme:

wherein ξ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ξ_kmin/ξ_kmaxFor a single evaluation index upper/lower limit, lambda_kAre weight coefficients.

3) Designing an orthogonal gauge head, determining a test scheme, and performing 9 tests to obtain a test result;

4) calculating extreme differences according to test results, determining primary and secondary sequences of factors, and obtaining each evaluation index ξ_kAccording to a weight coefficient lambda_kDetermining an optimization scheme;

the mechanical-hydraulic compound gear optimization scheme is determined by the following formula:

wherein ξ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ξ_kmin/ξ_kmaxFor a single evaluation index upper/lower limit, lambda_kIs a weight coefficient;

5) if the optimization scheme can not meet the requirements, the time of 'advance' and 'delay' can be increased or reduced, and different 'advance' time and 'delay' time can be selected until the requirements are met;

6) and controlling the switching time sequence of each group of gear shifting elements through the gear shifting mechanism switching time sequence data obtained under different working conditions.

9. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 5, wherein: when the gears of the pure mechanical transmission mode are switched, the mechanical I gear is switched to the mechanical II gear, which relates to 1 gear shifting element, the mechanical II gear is switched to the mechanical III gear, which relates to 1 gear shifting element, the mechanical III gear is switched to the mechanical IV gear, which relates to 3 gear shifting elements, the mechanical I gear is switched to the mechanical III gear, which relates to 2 gear shifting elements, the mechanical I gear is switched to the mechanical IV gear, which relates to 5 gear shifting elements, and the mechanical II gear is switched to the mechanical IV gear, which relates to 4 gear shifting elements;

gear shifts involving 2 and less shift elements can be optimized by not more than 3 trials; the gear shifts which relate to 3 shifting elements and in which 2 shifting elements have an interaction, the gear shifts which relate to 5 shifting elements and in which 3 shifting elements have an interaction, and the gear shifts which relate to 4 shifting elements and in which 2 shifting elements have an interaction are each evaluated using orthogonal tables, with the corresponding tables being selected for the evaluation;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing orthogonal analysis without interaction; test data are obtained through tests; calculating extreme differences according to test data, determining the primary and secondary sequences of factors, and obtaining the optimal scheme of each evaluation index; determining an optimization scheme according to the weight coefficient; and forming the optimization schemes under different working conditions into a matrix arrangement program to control the switching between gears.

10. The control method of a multi-power-split mode electro-hydraulic compound transmission as claimed in claim 9, wherein: the control method for the gear switching of the pure mechanical transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

the output shaft angular velocity variation is:

where α is the output shaft angular velocity variation,

the output shaft angular velocity change rate is defined as:

β is the change rate of the angular speed of the output shaft;

output shaft torque:

T_o＝β·J_o

in the formula T_oFor output shaft torque, J_oIs the rotational inertia of the output shaft;

the second derivative of the angular velocity of the output shaft is:

in the formula, gamma is the second derivative of the angular velocity of the output shaft

The jerk is the rate of change of the vehicle longitudinal acceleration:

wherein j is the impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) l shown in Table 2 was established₂₇(3¹³) An orthogonal table; in the table, "1", "2" and "3" represent the relevant shifting elements "shift early", "on time" and "delayed", respectively; "a" and "b" represent non-interacting shifting elements, respectively; "c", "d" and "e" have interacting shift elements, respectively;

n is the total number of tests, n is 27,

TABLE 3 orthogonal table for mechanical transmission mode element switching timing

The symbols in the table are expressed as follows:

3) designing an orthogonal gauge head as shown in Table 3, defining a test scheme, and performing 27 times of tests to obtain a test result x_i(i 1.., 27), calculating a correlation statistic;

4) determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, determining an F value, comparing the F value with a critical value, and determining the significance of the factors and the errors;

TABLE 4 ANALYSIS TABLE FOR TIME-SEQUENCE ANALYSIS OF SWITCHING OF MECHANICAL TRANSMISSION MODE ELEMENTS

Sum of squared deviations Q_TSum of squared deviations Q of the respective factors_FSum error squared sum of squared deviations Q_eRespectively as follows:

Q_T＝W-P＝∑Q_F+Q_e

Q_F＝U_F-P

total degree of freedom f_T26, degree of freedom of each factor f_F2, degree of freedom of error f_e＝4；

The mean squared deviations sum of the factors and errors is:

f value:

the ANOVA table for the switching timing of the mechanical transmission mode elements is shown in Table 4:

the variance sources mainly comprise ① ' a ', ' b ', ' c ','d ' and ' e '; ② ' e × c ' (including e × c1 and e × c 2), and ' e × d ' (including e ' sTwo parts d1 and e × d2) and "c × d" (including two parts c × d1 and c × d2), ③ error e^*；

F is calculated according to the variance source factors and the variance square sum, the freedom degree and the average variance square sum of errors_F

Value sum F_α(f_F，f_e) Comparing the values;

if F_F＞F_α(f_F，f_e) Then the factor effect is significant, otherwise it is not significant. And selecting the significant factors, visually analyzing the importance of each factor, and determining the optimal gear shifting scheme.

The mechanical gear optimization scheme is determined by the following formula:

in the formula, zeta is a comprehensive evaluation index_kAs a single evaluation index, ζ_kmin/ζ_kmaxUpper/lower limits for individual evaluation indices, μ_kIs a weight coefficient;

and controlling the switching time sequence of each group of gear shifting elements through the gear shifting mechanism switching time sequence data obtained under different working conditions.

Technical Field

The invention relates to a transmission device and a control method thereof, in particular to a multi-power distribution mode mechanical hydraulic composite transmission device and a control method thereof.

Background

The engineering operation equipment requires the transmission device to provide a transmission ratio with large torque and low rotating speed during starting or moving operation, and requires the transmission device to provide a transmission ratio with small torque and high rotating speed during transition. Therefore, the transmission device of the engineering operation equipment has higher requirements and more complex structure than the transmission device of the common vehicle due to the complexity of the use working conditions of the engineering operation equipment, and the transmission device of the engineering operation equipment has higher requirements on the transmission ratio and the torque at the same time.

The transmission device has important influence on the fuel economy of engineering operation equipment, and the engine is controlled to operate under the economic working condition as much as possible through the transmission device, so that the improvement of the fuel economy is facilitated. However, the transmission device of the traditional engineering machinery consists of a hydraulic torque converter and a gearbox, which are commonly called a double-variable system; the hydraulic torque converter is used for enabling the engine and the gearbox to be in non-rigid connection, and transmitting the rotating speed and the torque of the engine to the gearbox; the final transmission ratio change of the engineering operation equipment is realized through gear switching of the gearbox, belongs to the traditional mechanical transmission mode, and cannot meet the requirement of complex working conditions on the transmission ratio.

At present, a hydraulic transmission system for driving a hydraulic pump and further driving a hydraulic motor to travel through an engine appears in engineering operation equipment, but the transmission medium of the hydraulic transmission system is hydraulic oil, high-pressure oil can be generated in the transmission process, the requirement on the sealing performance between elements is high, the requirement on the pressure resistance of a hydraulic element is high, and the element cost is high; and the transmission efficiency is not high compared to a mechanical transmission system.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to solve the problems and provides a multi-power distribution mode mechanical-hydraulic compound transmission device and a control method. The invention can provide various power distribution modes according to complex operation conditions, fully utilizes the high-efficiency transmission performance of mechanical transmission and the stepless speed regulation performance of hydraulic transmission, and is beneficial to improving the operation efficiency, the dynamic property and the economical efficiency of vehicles.

The technical scheme is as follows: a multi-power distribution mode mechanical hydraulic compound transmission device comprises an input shaft, a flow dividing mechanism, a mechanical transmission assembly, a hydraulic transmission assembly and an output shaft, wherein the input shaft is connected with the mechanical transmission assembly and the hydraulic transmission assembly which are connected in parallel through the flow dividing mechanism, and the mechanical transmission assembly and the hydraulic transmission assembly are simultaneously connected with the output shaft; the mechanical transmission assembly comprises a front planet row assembly and a rear planet row assembly which are connected in series;

the front planet row component comprises a first clutch, a second clutch, a third clutch, a front planet row gear ring, a front planet row planet carrier, a front planet row sun gear and a first one-way clutch, the first clutch is positioned between the flow dividing mechanism and the front planet row gear ring, the second clutch and the third clutch are mutually connected in parallel and are respectively connected with the front planet row sun gear, the first one-way clutch is arranged between the third clutch and the front planet row sun gear, and the output shaft is connected with the front planet row planet carrier;

the rear planet row component comprises a fourth clutch, a rear planet row sun gear, a rear planet row planet carrier, a rear planet row gear ring, a first brake, a second brake and a second one-way clutch, wherein the fourth clutch is positioned between a shunting mechanism and the rear planet row sun gear, the first brake is connected with the rear planet row sun gear, the rear planet row planet carrier is connected with the front planet row gear ring and connected with the second brake and the second one-way clutch which are connected in parallel, and the rear planet row gear ring is connected with an output shaft.

The hydraulic transmission assembly comprises a hydraulic transmission input clutch, a hydraulic transmission input gear pair, a hydraulic pump, a hydraulic oil pipe, a hydraulic motor, a hydraulic transmission output gear pair and a hydraulic transmission output clutch; the hydraulic pump is connected with the shunting mechanism through a hydraulic transmission input gear pair, a hydraulic transmission input clutch is arranged between the hydraulic transmission input gear pair and the hydraulic pump, the hydraulic pump is connected with a hydraulic motor through a hydraulic oil pipe, the hydraulic motor is connected with an output shaft through a hydraulic transmission output gear pair, and the hydraulic motor is provided with a hydraulic transmission output clutch through the hydraulic transmission output gear pair.

The shunting mechanism comprises a shunting brake, a shunting mechanism sun gear, a shunting mechanism planet carrier and a shunting mechanism gear ring; the input shaft is connected with a gear ring of the shunting mechanism, a sun gear of the shunting mechanism is connected with the hydraulic transmission assembly, a shunting brake is arranged on the sun gear of the shunting mechanism, and a planet carrier of the shunting mechanism is connected with the mechanical transmission assembly.

The three types of transmission, namely pure hydraulic transmission, mechanical hydraulic composite transmission and pure mechanical transmission, are realized through the combined switching between the brake and the clutch, and the specific transmission types are as follows:

pure hydraulic transmission: the hydraulic transmission system comprises a first brake, a hydraulic transmission input clutch, a hydraulic transmission output clutch and a fourth clutch, wherein the other clutches are separated from the brake, the fourth clutch is connected with the first brake, a planet carrier of a splitting mechanism is braked, the hydraulic transmission input clutch is connected with the hydraulic transmission output clutch, power drives a hydraulic pump to work through an input shaft, a gear ring of the splitting mechanism, a sun gear of the splitting mechanism, a hydraulic transmission input gear pair and the input clutch, the hydraulic pump converts mechanical power into high-pressure oil and drives a hydraulic motor to work through a hydraulic pipeline, and the mechanical power output by the hydraulic motor is transmitted to an output shaft through the hydraulic transmission output clutch and the hydraulic transmission output gear pair;

pure mechanical transmission: the hydraulic transmission system comprises a hydraulic transmission assembly, a split-flow brake, a hydraulic transmission input clutch, a hydraulic transmission output clutch, a second brake and a fourth clutch, wherein the split-flow brake is connected, the combination of other clutches and brakes is used for realizing the switching between gears with different transmission ratios in a pure mechanical transmission mode, the split-flow brake is connected, the hydraulic transmission input clutch is separated from the hydraulic transmission output clutch, the hydraulic transmission assembly is in unpowered input, power is transmitted to the mechanical transmission assembly through an input shaft, a split-flow mechanism gear ring and a split-flow mechanism planet carrier, and the mechanical transmission assembly is output from an output shaft after the speed ratio is adjusted;

mechanical hydraulic composite transmission: the hydraulic transmission input clutch is connected with the hydraulic transmission output clutch, the shunt brake, the third clutch, the first one-way clutch and the second one-way clutch are separated, the gears with different transmission ratios in a mechanical hydraulic compound transmission mode are switched through the combination of other clutches and the brake, power is shunted at the position of the shunt mechanism planet carrier through the input shaft, the shunt mechanism gear ring and the shunt mechanism planet carrier, flows to the mechanical transmission assembly and the shunt mechanism sun gear respectively, and the shunt mechanism sun gear is connected with the hydraulic transmission assembly and finally converges to the output shaft for output.

The pure mechanical transmission mode comprises a mechanical transmission I gear, a mechanical transmission II gear, a mechanical transmission III gear and a mechanical transmission IV gear, and the specific implementation method comprises the following steps:

mechanical transmission I gear: the first brake, the first clutch and the second clutch are separated, the third clutch, the first one-way clutch and the second one-way clutch are connected, and power sequentially passes through the third clutch, the first one-way clutch and the front planet row planet carrier of the front planet row sun gear from the planet carrier of the shunting mechanism to the output shaft;

mechanical transmission II: the first brake, the first clutch, the second clutch and the second one-way clutch are separated, the third clutch and the first one-way clutch are connected, power sequentially passes through the third clutch, the first one-way clutch and the front planet row sun gear from the planet carrier of the shunting mechanism to the planet carrier of the front planet row, the power at the planet carrier of the front planet row is respectively shunted to the output shaft and the gear ring of the front planet row, and the power of the gear ring of the front planet row is sequentially transmitted to the planet carrier of the rear planet row and the gear ring of the rear planet row and finally converged to the output shaft;

mechanical transmission III gear: the first brake, the second clutch and the second one-way clutch are separated, the first clutch, the third clutch and the first one-way clutch are connected, power is input to the first clutch from the planet carrier of the shunting mechanism and shunted, flows to the front planet row gear ring and the front planet row sun gear to converge on the front planet row planet carrier respectively, and is finally output from the output shaft;

mechanical transmission IV gear: the second clutch, the third clutch, the first one-way clutch and the second one-way clutch are separated, the first clutch is connected with the first brake, and power is output from the planet carrier of the shunting mechanism to the output shaft through the first clutch, the front planet row gear ring, the rear planet row planet carrier and the rear planet row gear ring in sequence.

The mechanical hydraulic composite transmission mode comprises a composite transmission I gear, a composite transmission II gear, a composite transmission III gear and a composite transmission IV gear, and the specific implementation method comprises the following steps:

compound transmission I gear: the first brake, the first clutch and the fourth clutch are separated, the second brake is connected with the second clutch, power is split from a split mechanism planet carrier from a split mechanism gear ring, one part of power flows to the hydraulic transmission assembly from the split mechanism planet carrier through a split mechanism sun gear, the other part of power sequentially flows from the split mechanism planet carrier through the second clutch, the front planet row sun gear and the front planet row planet carrier, and finally converges to an output shaft for output;

compound transmission II: the second brake, the first clutch and the fourth clutch are separated, the first brake and the second clutch are connected, power is split from a split mechanism planet carrier from a split mechanism gear ring, one part of power flows to the hydraulic transmission assembly from the split mechanism planet carrier through a split mechanism sun gear, the other part of power sequentially flows to a front planet carrier from the split mechanism planet carrier through the second clutch and a front planet row sun gear, the power at the front planet row planet carrier is split to the output shaft and the front planet row gear ring respectively, the power of the front planet row gear ring is sequentially transmitted to a rear planet row planet carrier and a rear planet row gear ring, and the split three groups of power are finally converged to the output shaft;

compound transmission III: the first brake, the second brake and the fourth clutch are separated, the first clutch and the second clutch are connected, power is split from a split mechanism gear ring from a split mechanism planet carrier, one part of power flows to the hydraulic transmission assembly from the split mechanism planet carrier through a split mechanism sun gear, the other part of power is split from the split mechanism planet carrier and is input to the second clutch, the split power flows to a front planet row gear ring and a front planet row sun gear to converge on the front planet row planet carrier respectively, and the mechanical transmission assembly and the hydraulic transmission assembly converge and output on an output shaft;

compound transmission IV gear: the first brake, the first clutch and the second clutch are separated, the second brake is connected with the fourth clutch, power is split from the split mechanism planet carrier from the split mechanism gear ring, one part of power flows to the hydraulic transmission assembly from the split mechanism planet carrier through the split mechanism sun gear, the other part of power flows to the output shaft from the split mechanism planet carrier sequentially through the fourth clutch, the rear planet row sun gear and the rear planet row gear ring, and the mechanical transmission assembly and the hydraulic transmission assembly are converged and output at the output shaft.

TABLE 1 relationship table of transmission gears and shift elements

Note that "▲" represents the elements in the engaged state;

note: b is₁Is a shunt brake B₂Is a first brake, B₃Is a second brake, C₁Input clutches for hydraulic transmission, C₂For hydraulic transmission output clutch, C₃Is a fourth clutch C₄Is a first clutch C₅Is a second clutch, C₆Is a third clutch F₁Is a first one-way clutch, F₂Is a second one-way clutch.

When the gears of the mechanical hydraulic compound transmission mode are switched, a compound transmission I gear → a compound transmission II gear relates to 2 shifting elements, a compound transmission II gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission III gear → a compound transmission IV gear relates to 4 shifting elements, a compound transmission I gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission I gear → a compound transmission IV gear relates to 2 shifting elements, and a compound transmission II gear → a compound transmission IV gear relates to 4 shifting elements;

gear shifts involving 2 and less shift elements can give an optimum solution by not more than 3 trials; the gear shifts involving 3 or 4 shift elements and no interaction are analyzed by an orthogonal table; gear shifting involving 4 shift elements makes full use of 4 columns of the orthogonal table, and gear shifting involving 3 shift elements selects any 3 columns of the orthogonal table;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing interactive orthogonal analysis; test data are obtained through tests; determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, comparing the dispersion square sum and the degree of freedom with a critical value, and determining the significance of the factors and the errors; obtaining the optimal scheme of each evaluation index, and determining the optimal scheme according to the weight coefficient; and controlling the switching time sequence of each group of gear shifting elements in groups according to the gear shifting mechanism switching time sequence data obtained under different working conditions.

The control method for gear switching of the mechanical hydraulic compound transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the gear shifting time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

the output shaft angular velocity variation is defined as:

where α is the output shaft angular velocity variation,

for steady angular velocity of the output shaft, omega_ominIs the lowest angular velocity of the output shaft;

the output shaft angular velocity change rate is defined as:

β is the change rate of the angular speed of the output shaft;

the torque of the output shaft is:

T_o＝β·J_o

in the formula T_oFor output shaft torque, J_oIs the rotational inertia of the output shaft;

the second derivative of the output shaft angular velocity is defined as:

in the formula, gamma is the second differential of the angular velocity of the output shaft;

the jerk is the rate of change of the vehicle longitudinal acceleration:

wherein j is the impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) establishing L as shown in Table 2₉(3⁴) An orthogonal table; in the table, "1", "2" and "3" are three levels, representing the relevant shifting elements "advanced", "on time" and "delayed" shift, respectively; "a", "b", "c" and "d" are four factors, respectively representing non-interacting shifting elements; n is the total number of tests, n is 9, K_i ^FIs the sum of the test results associated with the ith level of the factor (i e (1, 2,3), F e (a, b, c, d));

TABLE 2 orthogonal table for mechanical hydraulic compound transmission mode element switching time sequence

The symbols in the table are expressed as follows:

extremely poor:

determining the primary and secondary sequence of each factor through range data, determining the optimal scheme of a single evaluation index, and finally determining the optimal scheme according to the weight coefficient;

and (3) determining an optimal scheme:

wherein ξ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ξ_kmin/ξ_kmaxFor a single evaluation index upper/lower limit, lambda_kAre weight coefficients.

3) Designing an orthogonal gauge head, determining a test scheme, and performing 9 tests to obtain a test result;

4) calculating extreme differences according to test results, determining primary and secondary sequences of factors, and obtaining each evaluation index ξ_kAccording to a weight coefficient lambda_kDetermining an optimization scheme;

the mechanical-hydraulic compound gear optimization scheme is determined by the following formula:

wherein ξ is a comprehensive evaluation index, ξ_kAs a single evaluation fingerLabel ξ_kmin/ξ_kmaxFor a single evaluation index upper/lower limit, lambda_kIs a weight coefficient;

5) if the optimization scheme can not meet the requirement, the time of 'advance' and 'delay' can be increased or decreased, and different 'advance' time and 'delay' time can be selected until the requirement is met.

When the gears of the pure mechanical transmission mode are switched, the mechanical I gear is switched to the mechanical II gear, which relates to 1 gear shifting element, the mechanical II gear is switched to the mechanical III gear, which relates to 1 gear shifting element, the mechanical III gear is switched to the mechanical IV gear, which relates to 3 gear shifting elements, the mechanical I gear is switched to the mechanical III gear, which relates to 2 gear shifting elements, the mechanical I gear is switched to the mechanical IV gear, which relates to 5 gear shifting elements, and the mechanical II gear is switched to the mechanical IV gear, which relates to 4 gear shifting elements;

gear shifts involving 2 and less shift elements can be optimized by not more than 3 trials; the gear shifts which relate to 3 shifting elements and in which 2 shifting elements have an interaction, the gear shifts which relate to 5 shifting elements and in which 3 shifting elements have an interaction, and the gear shifts which relate to 4 shifting elements and in which 2 shifting elements have an interaction are each evaluated using orthogonal tables, with the corresponding tables being selected for the evaluation;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing orthogonal analysis without interaction; test data are obtained through tests; calculating extreme differences according to test data, determining the primary and secondary sequences of factors, and obtaining the optimal scheme of each evaluation index; determining an optimization scheme according to the weight coefficient; and forming the optimization schemes under different working conditions into a matrix arrangement program to control the switching between gears.

The control method for the gear switching of the pure mechanical transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

the output shaft angular velocity variation is defined as:

where α is the output shaft angular velocity variation,

for steady angular velocity of the output shaft, omega_ominIs the lowest angular velocity of the output shaft; the output shaft angular velocity change rate is defined as:

β is the change rate of the angular speed of the output shaft;

the output shaft torque is determined by the equation:

T_o＝β·J_o

in the formula T_oFor output shaft torque, J_oIs the rotational inertia of the output shaft;

the second derivative of the output shaft angular velocity is defined as:

in the formula, gamma is the second differential of the angular velocity of the output shaft;

the jerk is the rate of change of the longitudinal acceleration of the vehicle, and is determined by the equation:

in the formula: j is the degree of impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) l shown in Table 3 was established₂₇(3¹³) An orthogonal table; in the table, the number of the first and second,"1", "2" and "3" represent the relevant shifting elements "advanced", "on time" and "delayed" shifting, respectively; "a" and "b" represent non-interacting shifting elements, respectively; "c", "d" and "e" have interacting shift elements, respectively;

n is the total number of tests, n is 27,as the sum of the test results associated with the ith level of the factor (i e (1, 2,3), F e (e, c, e × c1, e × c2, d, e × d1, e × d2, c × d1, a, b, c × d 2));

TABLE 3 orthogonal table for mechanical transmission mode element switching timing

The symbols in the table are expressed as follows:

3) designing an orthogonal gauge head as shown in Table 4, defining a test scheme, and performing 27 times of tests to obtain a test result x_i(i 1.., 27), calculating a correlation statistic;

4) determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, determining an F value, comparing the F value with a critical value, and determining the significance of the factors and the errors;

TABLE 4 ANALYSIS TABLE FOR TIME-SEQUENCE ANALYSIS OF SWITCHING OF MECHANICAL TRANSMISSION MODE ELEMENTS

Sum of squared deviations Q_TSum of squared deviations Q of the respective factors_FSum error squared sum of squared deviations Q_eRespectively as follows:

Q_T＝W-P＝∑Q_F+Q_e

Q_F＝U_F-P

total degree of freedom f_T26, degree of freedom of each factor f _F2, degree of freedom of error f_e＝4；

The mean squared deviations sum of the factors and errors is:

f value:

the variance analysis table of the mechanical transmission mode element switching time sequence is shown in table 1:

the variance sources mainly comprise ① 'a', 'b', 'c','d' and 'e'; ② 'e × c' (including two parts of e × c1 and e × c 2), 'e × d' (including two parts of e × d1 and e × d2) and 'c × d' (including two parts of c × d1 and c × d 2); ③ error e^*；

F is calculated according to the variance source factors and the variance square sum, the freedom degree and the average variance square sum of errors_F

Value sum F_α(f_F，f_e) The values are compared；

If F_F＞F_α(f_F，f_e) Then the factor effect is significant, otherwise it is not significant. And selecting the significant factors, visually analyzing the importance of each factor, and determining the optimal gear shifting scheme.

The mechanical gear optimization scheme is determined by the following formula:

in the formula, ζ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ζ_kmin/ζ_kmaxUpper/lower limits for individual evaluation indices, μ_kAre weight coefficients.

Has the advantages that: 1. the invention can switch among hydraulic transmission, mechanical-hydraulic composite transmission and mechanical transmission, each transmission mode has a plurality of gears to be selected, various power distribution modes can be provided according to complex operation working conditions, the transmission performance of the mechanical transmission and the stepless speed regulation performance of the hydraulic transmission are fully utilized, and the invention is beneficial to improving the operation efficiency, the dynamic property and the economical efficiency of vehicles. 2. The mechanical gear shifting device adopts the one-way clutch, so that the engine can be braked, and all shifting elements can be uniformly used to prolong the service life.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic diagram of the power flow of the pure hydraulic transmission of the present invention;

FIG. 3 is a schematic power flow diagram of the mechanical transmission of the present invention in gear I;

FIG. 4 is a schematic diagram of the power flow of the second gear of the mechanical transmission of the present invention;

FIG. 5 is a schematic view of the power flow of the mechanical transmission in gear III of the present invention;

FIG. 6 is a schematic diagram of the power flow of the mechanical transmission of the present invention in IV gear;

FIG. 7 is a schematic illustration of the power flow of the compound transmission of the present invention in gear I;

FIG. 8 is a schematic representation of the power flow direction of the compound transmission of the present invention in gear II;

FIG. 9 is a schematic view of the power flow direction of the compound transmission of the present invention in third gear;

FIG. 10 is a schematic diagram of the power flow of the compound transmission of the present invention in IV gear;

table 1 is a table of the relationship between transmission gears and shift elements of the present invention;

table 2 is a mechanical hydraulic composite transmission mode element switching timing orthogonal table of the present invention;

table 3 is a timing orthogonal table for switching elements in mechanical transmission mode according to the present invention;

table 4 is an ANOVA table for the switching timing of mechanical transmission mode elements according to the present invention.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1, the multi-power distribution mode mechanical hydraulic compound transmission device comprises an input shaft 1, a shunt mechanism 2, a mechanical transmission assembly 3, a hydraulic transmission assembly 4 and an output shaft 5, wherein the input shaft 1 is connected with the mechanical transmission assembly 3 and the hydraulic transmission assembly 4 which are connected in parallel through the shunt mechanism 2, and the mechanical transmission assembly 3 and the hydraulic transmission assembly 4 are simultaneously connected with the output shaft 5; the mechanical transmission assembly 3 comprises a front planet row assembly 31 and a rear planet row assembly 32 which are connected in series;

the front planetary gear set assembly 31 comprises a first clutch 311, a second clutch 312, a third clutch 313, a front planetary gear set ring gear 314, a front planetary gear set planet carrier 315, a front planetary gear set sun gear 316 and a first one-way clutch 317, wherein the first clutch 311 is positioned between the flow dividing mechanism 2 and the front planetary gear set ring gear 314, the second clutch 312 and the third clutch 313 are mutually connected in parallel and are respectively connected with the front planetary gear set sun gear 316, the first one-way clutch 317 is arranged between the third clutch 313 and the front planetary gear set sun gear 316, and the output shaft 5 is connected with the front planetary gear set planet carrier 315;

the rear planetary row assembly 32 includes a fourth clutch 321, a rear planetary row sun gear 322, a rear planetary row carrier 323, a rear planetary row ring gear 324, a first brake 325, a second brake 326 and a second one-way clutch 327, the fourth clutch 321 is located between the shunt mechanism 2 and the rear planetary row sun gear 322, the first brake 325 is connected with the rear planetary row sun gear 322, the rear planetary row carrier 323 is connected with the front planetary row ring gear 314 and is connected with the second brake 326 and the second one-way clutch 327 which are connected in parallel, and the rear planetary row ring gear 324 is connected with the output shaft 5.

The hydraulic transmission assembly 4 comprises a hydraulic transmission input clutch 41, a hydraulic transmission input gear pair 42, a hydraulic pump 43, a hydraulic oil pipe 44, a hydraulic motor 45, a hydraulic transmission output gear pair 46 and a hydraulic transmission output clutch 47; the hydraulic pump 43 is connected with the flow dividing mechanism 2 through a hydraulic transmission input gear pair 42, a hydraulic transmission input clutch 41 is arranged between the hydraulic transmission input gear pair 42 and the hydraulic pump 43, the hydraulic pump 43 is connected with a hydraulic motor 45 through a hydraulic oil pipe 44, the hydraulic motor 45 is connected with the output shaft 5 through a hydraulic transmission output gear pair 46, and a hydraulic transmission output clutch 47 is arranged between the hydraulic motor 45 and the hydraulic transmission output gear pair 46.

The shunting mechanism 2 comprises a shunting brake 21, a shunting mechanism sun gear 22, a shunting mechanism planet carrier 23 and a shunting mechanism gear ring 24; the input shaft 1 is connected with a shunting mechanism gear ring 24, a shunting mechanism sun gear 22 is connected with a hydraulic transmission assembly 4, a shunting brake 21 is arranged on the shunting mechanism sun gear 22, and a shunting mechanism planet carrier 23 is connected with a mechanical transmission assembly 3.

As shown in table 1, three types of transmissions, namely, a pure hydraulic transmission, a mechanical hydraulic compound transmission and a pure mechanical transmission, are realized by the combined switching between the brake and the clutch, and the specific transmission types are as follows:

as shown in fig. 2, pure hydraulic transmission: the first brake 325, the hydraulic transmission input clutch 41, the hydraulic transmission output clutch 47 and the fourth clutch 321 are engaged, other clutches and brakes are disengaged, the fourth clutch 321 is engaged with the first brake 325, the splitting mechanism planet carrier 23 is braked, the hydraulic transmission input clutch 41 is engaged with the hydraulic transmission output clutch 47, power drives the hydraulic pump 43 to work through the input shaft 1, the splitting mechanism ring gear 24, the splitting mechanism sun gear 22, the hydraulic transmission input gear pair 42 and the input clutch 41, the hydraulic pump 43 converts mechanical power into high-pressure oil and drives the hydraulic motor 45 to work through the hydraulic pipeline 44, and mechanical power output by the hydraulic motor 45 is transmitted to the output shaft 5 through the hydraulic transmission output clutch 47 and the hydraulic transmission output gear pair 46;

as shown in fig. 3, 4, 5 and 6, a purely mechanical transmission: the split-flow brake 21 is engaged, the hydraulic transmission input clutch 41, the hydraulic transmission output clutch 47, the second brake 326 and the fourth clutch 321 are separated, the combination of other clutches and brakes is used for realizing the switching among gears with different transmission ratios in a pure mechanical transmission mode, the split-flow brake 21 is engaged, the hydraulic transmission input clutch 41 and the hydraulic transmission output clutch 47 are separated, the hydraulic transmission assembly 4 is in unpowered input, power is transmitted to the mechanical transmission assembly 3 through the input shaft 1, the split-flow mechanism gear ring 24 and the split-flow mechanism planet carrier 23, and the mechanical transmission assembly 3 is output from the output shaft 5 after the speed ratio is adjusted;

as shown in fig. 7, 8, 9 and 10, the mechanical hydraulic compound transmission: the hydraulic transmission input clutch 41 is connected with the hydraulic transmission output clutch 47, the shunt brake 21, the third clutch 313, the first one-way clutch 317 and the second one-way clutch 327 are separated, switching among gears with different transmission ratios in a mechanical hydraulic compound transmission mode is realized through combination of other clutches and brakes, power is shunted at the position of the shunt mechanism planet carrier 23 through the input shaft 1 and the shunt mechanism gear ring 24 to the shunt mechanism planet carrier 23 and flows to the mechanical transmission assembly 3 and the shunt mechanism sun gear 22 respectively, and the shunt mechanism sun gear 22 is connected with the hydraulic transmission assembly 4 and finally converges to the output shaft 5 for output.

The pure mechanical transmission mode comprises a mechanical transmission I gear, a mechanical transmission II gear, a mechanical transmission III gear and a mechanical transmission IV gear, and the specific implementation method comprises the following steps:

as shown in fig. 3, mechanical transmission I: the first brake 325, the first clutch 311 and the second clutch 312 are disengaged, the third clutch 313, the first one-way clutch 317 and the second one-way clutch 327 are engaged, and power flows from the split mechanism carrier 23 to the output shaft 5 through the third clutch 313, the first one-way clutch 317 and the front planet carrier 315 in sequence from the front planet sun gear 316;

as shown in fig. 4, mechanical transmission gear ii: the first brake 325, the first clutch 311, the second clutch 312 and the second one-way clutch 327 are separated, the third clutch 313 and the first one-way clutch 317 are connected, power is sequentially transmitted from the split mechanism planet carrier 23 to the front planet carrier 315 through the third clutch 313, the first one-way clutch 317 and the front planet sun gear 316, the power at the front planet carrier 315 is respectively split to the output shaft 5 and the front planet ring gear 314, and the power of the front planet ring gear 314 is sequentially transmitted to the rear planet carrier 323 and the rear planet ring gear 324 and finally converged to the output shaft 5;

as shown in fig. 5, mechanical transmission gear iii: the first brake 325, the second clutch 312 and the second one-way clutch 327 are disengaged, the first clutch 311, the third clutch 313 and the first one-way clutch 317 are engaged, and power is input from the split mechanism carrier 23 to the first clutch 311, split and flow to the front planet carrier 314 and the front planet sun gear 316 respectively to be converged at the front planet carrier 315, and finally output from the output shaft 5;

as shown in fig. 6, the mechanical transmission iv gear: the second clutch 312, the third clutch 313, the first one-way clutch 317, and the second one-way clutch 327 are disengaged, the first clutch 311 and the first brake 325 are engaged, and power is output from the split mechanism carrier 23 to the output shaft 5 through the first clutch 311, the front carrier 314, the rear carrier 323, and the rear carrier 324 in this order.

The mechanical hydraulic composite transmission mode comprises a composite transmission I gear, a composite transmission II gear, a composite transmission III gear and a composite transmission IV gear, and the specific implementation method comprises the following steps:

as shown in fig. 7, compound drive I: the first brake 325, the first clutch 311 and the fourth clutch 321 are separated, the second brake 326 and the second clutch 312 are engaged, the power is split from the split mechanism gear ring 24 from the split mechanism planet carrier 23, a part of the power flows to the hydraulic transmission assembly 4 from the split mechanism planet carrier 23 through the split mechanism sun gear 22, and the other part of the power flows from the split mechanism planet carrier 23 to the output shaft 5 through the second clutch 312, the front planet row sun gear 316 and the front planet row planet carrier 315 in sequence and finally converges to output;

as shown in fig. 8, compound transmission gear ii: the second brake 326, the first clutch 311 and the fourth clutch 321 are separated, the first brake 325 and the second clutch 312 are engaged, power is split from the split mechanism gear ring 24 from the split mechanism planet carrier 23, a part of power flows to the hydraulic transmission assembly 4 from the split mechanism planet carrier 23 through the split mechanism sun gear 22, the other part of power sequentially flows to the front planet carrier 315 from the split mechanism planet carrier 23 through the second clutch 312 and the front planet carrier 316, the power at the front planet carrier 315 is respectively split to the output shaft 5 and the front planet gear ring 314, the power of the front planet gear ring 314 is sequentially transmitted to the rear planet carrier 323 and the rear planet gear ring 324, and the split three groups of power are finally converged to the output shaft 5;

as shown in fig. 9, compound drive iii: the first brake 325, the second brake 326 and the fourth clutch 321 are separated, the first clutch 311 and the second clutch 312 are engaged, power is split from the split mechanism ring gear 24 to the split mechanism planet carrier 23, a part of power flows from the split mechanism planet carrier 23 to the hydraulic transmission assembly 4 through the split mechanism sun gear 22, the other part of power flows from the split mechanism planet carrier 23 to the second clutch 312 and flows to the front planet row ring gear 314 and the front planet row sun gear 316 to be converged at the front planet row planet carrier 315, and the mechanical transmission assembly 3 and the hydraulic transmission assembly 4 output a confluence at the output shaft 5;

as shown in fig. 10, the compound transmission iv gear: the first brake 325, the first clutch 311 and the second clutch 312 are disengaged, the second brake 326 and the fourth clutch 321 are engaged, the power is split from the split mechanism carrier 23 from the split mechanism ring gear 24, a part of the power flows to the hydraulic transmission assembly 4 from the split mechanism carrier 23 through the split mechanism sun gear 22, another part of the power flows to the output shaft 5 from the split mechanism carrier 23 through the fourth clutch 321, the rear planet row sun gear 322 and the rear planet row ring gear 324 in sequence, and the mechanical transmission assembly 3 and the hydraulic transmission assembly 4 are converged and output on the output shaft 5.

When the gears of the mechanical hydraulic compound transmission mode are switched, a compound transmission I gear → a compound transmission II gear relates to 2 shifting elements, a compound transmission II gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission III gear → a compound transmission IV gear relates to 4 shifting elements, a compound transmission I gear → a compound transmission III gear relates to 2 shifting elements, a compound transmission I gear → a compound transmission IV gear relates to 2 shifting elements, and a compound transmission II gear → a compound transmission IV gear relates to 4 shifting elements;

gear shifts involving 2 and less shift elements can give an optimum solution by not more than 3 trials; the gear shifts involving 3 or 4 shift elements and no interaction are analyzed by an orthogonal table; gear shifting involving 4 shift elements makes full use of 4 columns of the orthogonal table, and gear shifting involving 3 shift elements selects any 3 columns of the orthogonal table;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing interactive orthogonal analysis; test data are obtained through tests; determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, comparing the dispersion square sum and the degree of freedom with a critical value, and determining the significance of the factors and the errors; obtaining the optimal scheme of each evaluation index, and determining the optimal scheme according to the weight coefficient; and controlling the switching time sequence of each group of gear shifting elements in groups according to the gear shifting mechanism switching time sequence data obtained under different working conditions.

The control method for gear switching of the mechanical hydraulic compound transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

the output shaft angular velocity variation is defined as:

wherein α is the change of angular velocity of output shaftThe chemical quantity is changed,

for steady angular velocity of the output shaft, omega_ominIs the lowest angular velocity of the output shaft;

the output shaft angular velocity change rate is defined as:

β is the change rate of the angular speed of the output shaft;

output shaft torque:

T_o＝β·J_o

in the formula T_oFor output shaft torque, J_oIs the rotational inertia of the output shaft;

the second derivative of the angular velocity of the output shaft is:

in the formula, gamma is the second differential of the angular velocity of the output shaft;

the jerk is the rate of change of the vehicle longitudinal acceleration:

wherein j is the impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) establishing L as shown in Table 2₉(3⁴) An orthogonal table; in the table, "1", "2" and "3" are three levels, representing the relevant shifting elements "advanced", "on time" and "delayed" shift, respectively; "a", "b", "c" and "d" are four factors, respectively representing non-interacting shifting elements; n is the total number of tests, n is 9, K_i ^FIs the sum of the test results associated with the ith level of the factor (i e (1, 2,3), F e (a, b, c, d));

taking the example of the composite transmission II gear being switched to the composite transmission IV:

the four factors are determined as the brake B2, the brake B3, the clutch C3 and the clutch C5, and the switching sequence of the 4 shifting elements is the four factors influencing the shifting quality of the transmission system.

The three levels are selected as the switching of the shifting elements, namely 'early', 'on time' and 'late', and the time of 'early' and 'late' can be selected according to actual conditions, and can be the same or different. For this example, the time for selecting "advance" and "retard" is 0.3 s.

TABLE 2 orthogonal table for mechanical hydraulic compound transmission mode element switching time sequence

	a	b	c	d	Test results xi
							1	2	3	4
1	1	1	1	1
						2	1	2	2	2
3	1	3	3	3
						4	2	1	2	3
5	2	2	3	1
						6	2	3	1	2
7	3	1	3	2
						8	3	2	1	3
9	3	3	2	1

The symbols in the table are expressed as follows:

extremely poor:

determining the primary and secondary sequence of each factor through range data, determining the optimal scheme of a single evaluation index, and finally determining the optimal scheme according to the weight coefficient;

and (3) determining an optimal scheme:

ξ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ξ_kmin/ξ_kmaxFor a single evaluation index upper/lower limit, lambda_kAre weight coefficients.

3) Designing an orthogonal gauge head, determining a test scheme, and performing 9 tests to obtain a test result;

4) calculating extreme differences according to test results, determining primary and secondary sequences of factors, and obtaining each evaluation index ξ_kAccording to a weight coefficient lambda_kDetermining an optimization scheme;

the mechanical-hydraulic compound gear optimization scheme is determined by the following formula:

ξ is a comprehensive evaluation index, ξ_kAs a single evaluation index, ξ_kmin/ζ_kmaxFor a single evaluation index upper/lower limit, lambda_kIs a weight coefficient;

5) if the optimization scheme can not meet the requirement, the time of 'advance' and 'delay' can be increased or decreased, and different 'advance' time and 'delay' time can be selected until the requirement is met.

The shifting mechanism switching time sequence data obtained under different working conditions are input to the shifting controller in groups, and the good shifting quality of the same transmission mode in the shifting process of each gear is guaranteed by controlling the switching time sequence of each group of shifting devices.

The same principle can be obtained when the compound transmission III gear is transited to the compound transmission IV gear, and only corresponding four factors and three levels need to be changed.

When the gears of the pure mechanical transmission mode are switched, the mechanical I gear is switched to the mechanical II gear, which relates to 1 gear shifting element, the mechanical II gear is switched to the mechanical III gear, which relates to 1 gear shifting element, the mechanical III gear is switched to the mechanical IV gear, which relates to 3 gear shifting elements, the mechanical I gear is switched to the mechanical III gear, which relates to 2 gear shifting elements, the mechanical I gear is switched to the mechanical IV gear, which relates to 5 gear shifting elements, and the mechanical II gear is switched to the mechanical IV gear, which relates to 4 gear shifting elements;

gear shifts involving 2 and less shift elements can be optimized by not more than 3 trials; the gear shifts which relate to 3 shifting elements and in which 2 shifting elements have an interaction, the gear shifts which relate to 5 shifting elements and in which 3 shifting elements have an interaction, and the gear shifts which relate to 4 shifting elements and in which 2 shifting elements have an interaction are each evaluated using orthogonal tables, with the corresponding tables being selected for the evaluation;

determining the variation of the angular speed of the output shaft, the variation rate of the angular speed of the output shaft, the second differential of the angular speed of the output shaft and time as evaluation indexes, selecting 'advance', 'on time' and 'delay' to be switched to three levels, and performing orthogonal analysis without interaction; test data are obtained through tests; calculating extreme differences according to test data, determining the primary and secondary sequences of factors, and obtaining the optimal scheme of each evaluation index; determining an optimization scheme according to the weight coefficient; and forming the optimization schemes under different working conditions into a matrix arrangement program to control the switching between gears.

The control method for the gear switching of the pure mechanical transmission mode comprises the following specific steps:

1) selecting the variation α of the angular speed of the output shaft, the variation rate β of the angular speed of the output shaft, the second differential gamma of the angular speed of the output shaft and the time t as evaluation indexes, wherein α, β and gamma are respectively zero-order, first-order and second-order differentials of the rotating speed and form a space-time evaluation index together with the time t;

variation α of output shaft angular velocity

The output shaft angular velocity variation is defined as:

wherein α is the variation of the angular velocity of the output shaft,

for steady angular velocity of the output shaft, omega_ominThe output shaft angular velocity change rate is defined as:

wherein β is the change rate of the angular speed of the output shaft

The output shaft torque is determined by equation (3):

T_o＝β·J_o

in the formula: t is_oFor output shaft torque, J_oIs the moment of inertia of the output shaft

The second derivative of the output shaft angular velocity is defined as:

in the formula: gamma is the second derivative of the angular velocity of the output shaft

The jerk is the rate of change of the vehicle longitudinal acceleration, and is determined by equation (5):

in the formula: j is the degree of impact, r_dIs the dynamic radius of the tire, i_gTo the transmission ratio of the variator, i₀Is the drive axle transmission ratio;

2) l shown in Table 3 was established₂₇(3¹³) An orthogonal table; in the table, "1", "2" and "3" represent the relevant shifting elements "shift early", "on time" and "delayed", respectively; "a" and "b" represent non-interacting shifting elements, respectively; "c", "d" and "e" have interacting shift elements, respectively;

take the example of the mechanical gear I shifting to the mechanical gear iv:

the "five factors" are determined to be the brake B2, the clutch C4, the clutch C6, the one-way clutch F1 and the one-way clutch F2, and the switching timing of these 5 shift elements is the five factors that affect the shift quality of the transmission system. The "five-factor" brake B2 and clutch C4 have no interaction, and clutch C6, one-way clutch F1 and one-way clutch F2 have interaction.

The three levels are selected as the switching of the shifting elements, namely 'early', 'on time' and 'late', and the time of 'early' and 'late' can be selected according to actual conditions, and can be the same or different. For the present example, the time for "advance" and "delay" is chosen to be 0.5s, since there are more components involved, among which there are interactions.

TABLE 3 orthogonal table for mechanical transmission mode element switching timing

n is the total number of tests, n is 27,as the sum of the test results associated with the ith level of the factor (i e (1, 2,3), F e (e, c, e × c1, e × c2, d, e × d1, e × d2, c × d1, a, b, c × d 2));

the symbols in the table are expressed as follows:

3) designing an orthogonal gauge head as shown in Table 3, defining a test scheme, and performing 27 times of tests to obtain a test result x_i(i 1.., 27), calculating a correlation statistic;

4) determining the dispersion square sum and the degree of freedom of the factors and the errors according to the analysis of variance table, determining an F value, comparing the F value with a critical value, and determining the significance of the factors and the errors;

TABLE 4 ANALYSIS TABLE FOR TIME-SEQUENCE ANALYSIS OF SWITCHING OF MECHANICAL TRANSMISSION MODE ELEMENTS

Sum of squared deviations Q_TSum of squared deviations Q of the respective factors_FSum error squared sum of squared deviations Q_eRespectively as follows:

Q_T＝W-P＝ΣQ_F+Q_e

Q_F＝U_F-P

total degree of freedom f_T26, degree of freedom of each factor f _F2, degree of freedom of error f_e＝4；

The mean squared deviations sum of the factors and errors is:

f value:

the variance analysis table of the mechanical transmission mode element switching time sequence is shown in table 1:

sources of variance① ' a ', b ', c ', d ' and ' e '; ② ' e × c ' (including two parts of e × c1 and e × c 2), ' e × d ' (including two parts of e × d1 and e × d2) and ' c × d ' (including two parts of c × d1 and c × d2), ③ error e^*；

F is calculated according to the variance source factors and the variance square sum, the freedom degree and the average variance square sum of errors_FValue sum F_α(f_F，f_e) Comparing the values;

if F_F＞F_α(f_F，f_e) Then the factor effect is significant, otherwise it is not significant. And selecting the significant factors, visually analyzing the importance of each factor, and determining the optimal gear shifting scheme.

The mechanical gear optimization scheme is determined by the following formula:

in the formula, zeta is a comprehensive evaluation index_kAs a single evaluation index, ζ_kmin/ζ_kmaxUpper/lower limits for individual evaluation indices, μ_kAre weight coefficients.

The shifting mechanism switching time sequence data obtained under different working conditions are input to the shifting controller in groups, and the good shifting quality of the same transmission mode in the shifting process of each gear is guaranteed by controlling the switching time sequence of each group of shifting devices.

The shift from mechanical III to mechanical IV involves 3 shift elements, wherein the third clutch 313 and the first one-way clutch 317 interact with each other, and L can be used₉(3⁴) And (4) analyzing the orthogonal table, and only replacing the fourth factor column with an interactive column.

The shift from mechanical II to mechanical IV involves 4 shift elements, wherein the third clutch 313 and the first one-way clutch 317 interact with each other, and L can be used₂₇(3¹³) The orthogonal table is analyzed, and the related redundant column is vacant.