All-in-one integrated electric drive and noise reduction design method and electric fork truck

Abstract

The application discloses a kind of multi-in-one integrated electric drive, noise reduction design method and electric forklift in the field of electric forklift integrated electric drive.The multi-in-one integrated electric drive includes two-in-one high-speed reducer, the two-in-one high-speed reducer includes reducer shell, walking gear train and hydraulic gear train, first chamber and second chamber are formed in reducer shell independently, by walking gear train and hydraulic gear train are respectively arranged in first chamber and second chamber, can effectively avoid the loss of two simultaneous work stirring oil turbulence.Through setting stator installation stopper, rotor installation bearing chamber and bolt hole in the side of reducer shell, walking motor and hydraulic motor are simultaneously integrated and installed on reducer shell, the front end cover of motor in traditional forklift multi-in-one assembly is saved, effectively save forklift installation space.The noise reduction design method proposed in the application can significantly improve the NVH performance of integrated electric drive.

Description

Technical Field

[0001] This invention belongs to the field of integrated electric drive for electric forklifts, specifically relating to an all-in-one integrated electric drive, a noise reduction design method, and an electric forklift. Background Technology

[0002] The market potential for electric forklifts is enormous. With continued economic development, higher demands are being placed on the forklift's travel and hydraulic drive subsystems and their integration into the vehicle. The reducer, as a key component of the integrated electric drive system, significantly impacts the overall driving experience. However, in actual forklift use, electric forklift reducers often experience vibration and noise issues, affecting not only passenger comfort but also potentially threatening the forklift's safety and reliability.

[0003] Current electric forklifts employ a limited technical approach to their travel and hydraulic drive subsystems and their overall vehicle layout. They typically consist of a travel drive system unit comprised of a drive motor and a front axle reduction gearbox, and a hydraulic drive system unit comprised of a hydraulic motor and hydraulic pump, or a hydraulic motor plus a reduction gearbox and hydraulic pump. The travel motor controller and hydraulic motor controller are separately located to form the motor control unit. The entire drive system is distributed over a wide area, with the travel drive system unit located at the front axle, the hydraulic drive unit at the middle and rear of the vehicle, and the motor control unit also located at the middle and rear of the vehicle. In this current layout, the travel and hydraulic drive subsystems are far from the motor controller unit, resulting in excessively long connecting cables. This leads to a cluttered and costly wiring harness, low energy efficiency, and ultimately, increased overall vehicle cost and energy consumption. Furthermore, the wide-area layout of the travel and hydraulic drive subsystems makes heat dissipation difficult and inefficient, requiring separate cooling for each unit. This results in an overly complex system and significantly increases prototype costs. The existing drive unit's reducer design initially followed the traditional internal combustion engine gearbox design approach, lacking noise reduction design methods. This results in high noise levels during actual high-speed operation. The reducer's vibration and noise mainly originate from multiple aspects, including gear meshing, bearing operation, and motor operation. These issues not only affect the driving and riding experience but may also impact the lifespan and performance of the vehicle's reducer. Long-term vibration and noise can lead to loosening, wear, or even breakage of internal reducer parts, thereby affecting vehicle safety.

[0004] Chinese invention patent application CN111976470A discloses a liquid-cooled electric forklift integrated power system and its control method, including an integrated transmission gearbox, an integrated motor controller, an oil pump, and a vehicle controller. The integrated transmission gearbox includes a drive motor transmission mechanism and an oil pump motor transmission mechanism. The integrated motor controller includes a drive motor control unit and an oil pump motor control unit. The integrated transmission gearbox, integrated motor controller, drive motor, oil pump motor, oil pump, and vehicle controller are fully integrated and assembled to form the liquid-cooled electric forklift integrated power system. The drive motor is fixed to the side of the integrated gearbox by bolts on the rear cover of the motor, and the oil pump motor is fixed to the side of the integrated gearbox by mounting bolts on the rear cover of the motor. However, this system has the following drawbacks: the travel reducer and hydraulic reducer are located in the same sealed chamber; electric forklifts often operate in parallel with both travel and hydraulic drive; the simultaneous operation of the travel reducer and hydraulic reducer causes mutual interference in oil flow, resulting in low efficiency; and the shared housing and end cover require simultaneous control of the distances from each bearing position to the end face, leading to high processing and assembly difficulty, high cost, and poor maintainability.

[0005] Chinese invention patent application CN110065911A discloses an integrated power system and control method for medium-to-large tonnage electric forklifts, including a drive power subsystem, a hydraulic power subsystem, and a host power control subsystem. The drive power subsystem includes a drive motor, a parallel shaft reducer, and a drive motor controller. The drive motor housing is fixedly connected to the parallel shaft reducer via a dual-motor front end cover. The drive motor controller is mounted on a dual-motor controller support plate, which is fixed to the front and rear end covers of the drive motor and the oil pump motor via several support points. The oil pump motor is fixedly connected to the parallel shaft reducer via the dual-motor front end cover; the oil pump motor controller is mounted on the dual-motor controller support plate. This system simply uses commercially available fuel vehicle reducers and performs a simple physical stacking. Furthermore, the reducer lacks targeted noise reduction design, and there are still numerous high and low voltage cables between the controller and the motor, resulting in significant space consumption and high cost. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an all-in-one integrated electric drive, noise reduction design method, and electric forklift.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an integrated electric drive comprising a two-in-one high-speed reducer, a hydraulic motor, and a travel motor. The two-in-one high-speed reducer includes a reducer housing, a travel reducer end cover, a hydraulic reducer end cover, a travel gear system, and a hydraulic gear system. The reducer housing comprises an integrally formed and mutually independent first housing and a second housing. The travel reducer end cover is fixedly connected to the first housing to form a first chamber. The hydraulic reducer end cover is fixedly connected to the second housing to form a second chamber. The travel gear system and the hydraulic gear system are respectively disposed in the first chamber and the second chamber via bearings. The output shaft of the hydraulic motor is coaxially connected to the input gear shaft of the hydraulic gear system, and the output shaft of the travel motor is coaxially connected to the input gear shaft of the travel gear system.

[0009] Furthermore, the side of the reducer housing is provided with a first mounting position and a second mounting position in parallel. The first mounting position includes a stator mounting stop, a rotor mounting bearing chamber, and several bolt holes. The stator of the hydraulic motor is mounted on the reducer housing through the stator mounting stop and fixed to the corresponding bolt holes in the reducer housing with long bolts. The rotor assembly mounting bearing of the hydraulic motor is mounted in the rotor mounting bearing chamber. The shaft of the hydraulic motor is coaxially connected to the input gear shaft of the hydraulic gear system. The second mounting position includes a stator mounting stop, a rotor mounting bearing chamber, and several bolt holes. The stator of the travel motor is mounted on the reducer housing through the stator mounting stop and fixed to the corresponding bolt holes in the reducer housing with long bolts. The rotor assembly mounting bearing of the travel motor is mounted in the rotor mounting bearing chamber. The shaft of the travel motor is coaxially connected to the input gear shaft of the travel gear system.

[0010] Furthermore, the traveling gear system includes an input gear shaft two, an intermediate shaft one, an intermediate shaft two, and an output gear shaft two arranged in parallel. A gear three is arranged on the input gear shaft two, a gear four and a gear five are arranged on the intermediate shaft one, a gear six and a gear seven are arranged on the intermediate shaft two, and a gear eight is arranged on the output gear shaft two. Gear four and gear three mesh to form a first-stage gear, gear six and gear five mesh to form a second-stage gear, and gear eight and gear seven mesh to form a third-stage gear. The center lines connecting the axes of the input gear shaft two, the intermediate shaft one, and the intermediate shaft two form a triangular arrangement.

[0011] Furthermore, the end cover of the travel reducer is fixedly connected to the first housing through the first bolt fixing hole.

[0012] Furthermore, the end cover of the travel reducer is provided with a plurality of bearing holes corresponding to each gear shaft of the travel gear system. The end cover of the travel reducer is provided with a plurality of first radial ribs around each bearing hole. The first radial ribs are distributed radially with each bearing hole as the center, and one end of each first radial rib is connected to the bearing hole and the other end is connected to the first bolt fixing hole.

[0013] Furthermore, the hydraulic reducer end cover is fixedly connected to the second housing through the second bolt fixing hole.

[0014] Furthermore, the hydraulic reducer end cover is provided with a plurality of bearing holes two corresponding to each gear shaft of the hydraulic gear system. The hydraulic reducer end cover is provided with a plurality of second radial ribs around each bearing hole two. The second radial ribs are distributed radially with each bearing hole two as the center, and one end of each second radial rib is connected to the bearing hole two, and the other end is connected to the second bolt fixing hole.

[0015] Furthermore, both the first chamber and the second chamber are provided with oil guide ribs and bearing oil inlets, which are arranged according to the direction of the oil flow in the gear agitator.

[0016] Secondly, this invention provides a multi-integrated electric drive noise reduction design method, comprising one or more of the following steps:

[0017] The design incorporates a first-order gear and motor order difference ≥ a first set value, and a second-order gear and motor order difference ≥ a second set value, to reduce resonance caused by the motor's pole slot number and its multiples being close to the reducer's order.

[0018] The design aims to ensure that the total overlap ratio of the primary gears is greater than or equal to the third set value, thereby reducing meshing stiffness and meshing fluctuation.

[0019] By micro-modifying the gears, the meshing misalignment of the first-stage gear is ≤ the fourth set value and the meshing misalignment of the second-stage gear is ≤ the fifth set value, so that the meshing area tends to be in the middle and the edge stress is reduced.

[0020] By micro-modifying the gears, the transmission error of the first-stage gear is made ≤ the sixth set value, the transmission error of the second-stage gear is made ≤ the seventh set value, and the transmission error of the third-stage gear is made ≤ the eighth set value, thereby reducing the amplitude of the dynamic excitation source.

[0021] The design of the reducer housing is such that the first-order bending mode is greater than or equal to the ninth set value x9, so that the excitation frequency avoids the natural frequency and prevents resonance.

[0022] Furthermore, the first setting value is 2, and the second setting value is 2;

[0023] The third setting value is 4;

[0024] The fourth setting is 1 μm / mm, and the fifth setting is 1.5 μm / mm;

[0025] The sixth setting is 1 μm, the seventh setting is 2 μm, and the eighth setting is 3 μm;

[0026] The ninth setting is 1500 Hz.

[0027] Furthermore, the all-in-one integrated electric drive noise reduction design method further includes:

[0028] By setting radial ribs around the reducer housing, the dynamic stiffness of the bearing holes is increased, and the deformation of the reducer housing under gear transmission error excitation is reduced.

[0029] Furthermore, the dynamic stiffness of the bearing bore is ≥15000 N / mm.

[0030] Thirdly, the present invention provides an electric forklift, including the all-in-one integrated electric drive as described in any of the first aspects.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. In this invention, the walking gear system and the hydraulic gear system are respectively set in different chambers within the housing through bearings at both ends, which can effectively avoid the loss of oil turbulence when the two work at the same time;

[0033] 2. The present invention adopts a scheme in which the travel reducer and the hydraulic reducer share a single housing. By setting a stator mounting stop, a rotor mounting bearing chamber, and bolt holes for fixing the motor stator on the side of the housing, the travel motor and the hydraulic motor are simultaneously and in parallel installed on the housing. This allows the housing to serve as the front cover for both the travel motor and the hydraulic motor, eliminating the need for a separate front cover for the motor in the traditional all-in-one forklift assembly. This effectively saves forklift installation space, significantly reduces the cost and weight of the drive assembly, and shortens its size.

[0034] 3. The center lines of the shafts of the traveling gear system are connected to form a triangle, which can effectively shorten the axial space occupied.

[0035] 4. The bearing positions of the traveling gear system and the hydraulic gear system are independent of each other, which can reduce the processing difficulty and save costs;

[0036] 5. The noise reduction design method for the all-in-one integrated electric drive proposed in this invention avoids coupling with the number of motor tooth slots by rationally designing the number of gear teeth, which can effectively avoid vibration and noise problems caused by the excitation frequency being close to the meshing frequency; by setting cross-radial ribs with the center of the bearing hole as the center around the bearing hole, the dynamic stiffness of the bearing is greatly improved without significantly increasing the weight, and the noise transmitted from the gear excitation to the housing surface is reduced, thereby significantly improving the NVH performance of the integrated electric drive. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of an all-in-one integrated electric drive structure according to the present invention;

[0038] Figure 2 This is a schematic diagram of the non-motor side structure of the two-in-one high-speed reducer of the present invention;

[0039] Figure 3 This is a layout diagram of the internal structure of the reducer housing of the present invention;

[0040] Figure 4 This is an isometric view of the walking gear system and hydraulic gear system of the present invention;

[0041] Figure 5 This is a schematic diagram of the motor side structure of the two-in-one high-speed reducer of the present invention;

[0042] Figure 6 This is a detailed view of the interior of the reducer housing of the present invention;

[0043] Figure 7 This is a structural diagram of the end cover of the travel reducer of the present invention;

[0044] Figure 8 This is a structural diagram of the hydraulic reducer end cover of the present invention;

[0045] Figure 9 This is a schematic diagram of the gear micro-shaping of the present invention.

[0046] In the diagram: 1. Two-in-one high-speed reducer; 2. Two-in-one controller; 3. Oil pump; 4. Hydraulic motor; 5. Travel motor; 101. Reducer housing; 102. Travel reducer end cover; 103. Hydraulic reducer end cover; 104. Travel gear system; 105. Hydraulic gear system; 106. First housing; 107. Second housing; 108. First chamber; 109. Second chamber; 401. Bearing mounting; 402. Rotor assembly; 403. Long bolt; 404. Stator; 10101. Stator mounting stop one; 10102. Rotor bearing mounting chamber one; 10103. Bolt hole one; 10104. Stator mounting stop two; 10105. Rotor bearing mounting chamber two; 10106. Bolt hole two; 10107. Oil guide rib; 10108. Bearing oil inlet. 10201, First bolt fixing hole; 10202, First radial rib; 10203, Bearing hole one; 10301, Second radial rib; 10302, Second bolt fixing hole; 10303, Bearing hole two; 10401, Input gear shaft two; 10402, Intermediate shaft one; 10403, Intermediate shaft two; 10404, Output gear shaft two; 10501, Input gear shaft one; 10502, Output gear shaft one; z1, Gear one; z2, Gear two; z3, Gear three; z4, Gear four; z5, Gear five; z6, Gear six; z7, Gear seven; z8, Gear eight. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0048] Example 1

[0049] like Figure 1 As shown, an all-in-one integrated electric drive includes a two-in-one high-speed reducer 1, a two-in-one controller 2, an oil pump 3, a hydraulic motor 4, and a travel motor 5.

[0050] like Figure 2 and Figure 3 As shown, the two-in-one high-speed reducer 1 includes a reducer housing 101, a travel reducer end cover 102, a hydraulic reducer end cover 103, a travel gear system 104, and a hydraulic gear system 105.

[0051] The reducer housing 101 includes an integrally formed and mutually independent first housing 106 and second housing 107. The travel reducer end cover 102 is fixedly connected to the first housing 106 to form a first chamber 108. The hydraulic reducer end cover 103 is fixedly connected to the second housing 107 to form a second chamber 109.

[0052] In one implementation, such as Figure 7 As shown, the end cover 102 of the travel reducer is fixedly connected to the first housing 106 through the first bolt fixing hole 10201.

[0053] In one implementation, such as Figure 8 As shown, the hydraulic reducer end cover 103 and the second housing 107 are fixedly connected through the second bolt fixing hole 10302.

[0054] like Figure 3 As shown, the traveling gear system 104 is disposed in the first chamber 108, and the hydraulic gear system 105 is disposed in the second chamber 109. By disposing of the traveling gear system and the hydraulic gear system in different chambers within the housing, turbulent flow losses caused by oil churning can be effectively avoided when both are working simultaneously.

[0055] Combination Figure 2 and Figure 3As shown, the gear shafts of the traveling gear system 104 are mounted on the first housing 106 of the first chamber 108 and the traveling reducer end cover 102 via bearings at both ends. Similarly, the gear shafts of the hydraulic gear system 105 are mounted on the second housing 107 of the second chamber 109 and the hydraulic reducer end cover 103 via bearings at both ends. The bearing positions of the traveling gear system and the hydraulic gear system are independent of each other, which reduces processing difficulty and saves costs.

[0056] The hydraulic motor 4 and the travel motor 5 are fixedly connected in parallel to one side of the reducer housing 101, in combination with... Figure 4 As shown, the output shaft of the hydraulic motor 4 is coaxially connected to the input gear shaft 10501 of the hydraulic gear system 105, the output gear shaft 10502 of the hydraulic gear system 105 is coaxially connected to the input shaft of the oil pump 3, and the output shaft of the travel motor 5 is coaxially connected to the input gear shaft 10401 of the travel gear system 104.

[0057] The integrated controller 2 includes a hydraulic motor control unit and a travel motor control unit integrated into one unit. The integrated controller 2 is located above the reducer housing 101, the hydraulic motor 4, and the travel motor 5. Both the hydraulic motor 4 and the travel motor 5 are electrically connected to the integrated controller 2. By integrating the hydraulic motor control unit and the travel motor control unit into one unit, forming a two-in-one controller for both hydraulic and travel motors, the number of connecting cables between the controller and the motors can be reduced. This not only avoids cluttered wiring harnesses throughout the vehicle but also reduces overall vehicle cost and lowers power transmission losses.

[0058] like Figure 4 As shown, the traveling gear system 104 is a three-stage parallel shaft transmission structure, including an input gear shaft 10401, an intermediate shaft 10402, an intermediate shaft 10403, and an output gear shaft 10404 arranged in parallel. Gear 3 (z3) is mounted on input gear shaft 10401; gears 4 (z4) and 5 (z5) are mounted on intermediate shaft 10402; gears 6 (z6) and 7 (z7) are mounted on intermediate shaft 10403; and gear 8 (z8) is mounted on output gear shaft 10404. Gears 4 (z4) and 3 (z3) mesh to form the first stage gear; gears 6 (z6) and 5 (z5) mesh to form the second stage gear; and gears 8 (z8) and 7 (z7) mesh to form the third stage gear. The axes of input gear shaft 10401, intermediate shaft 10402, and intermediate shaft 10403 are arranged in a triangular pattern, which significantly reduces the axial space.

[0059] The hydraulic gear system 105 is a single-stage parallel shaft transmission structure, including an input gear shaft 10501 and an output gear shaft 10502 arranged in parallel. Gear 1 z1 is arranged on the input gear shaft 10501, and gear 2 z2 is arranged on the output gear shaft 10502. Gear 1 z1 and gear 2 z2 mesh with each other.

[0060] like Figure 5 As shown, the reducer housing 101 has a first mounting position and a second mounting position arranged in parallel on the non-cavity side.

[0061] The first mounting position includes a stator mounting stop 10101, a rotor mounting bearing chamber 10102, and several bolt holes 10103 arranged around the stator mounting stop 10101. The stator 404 of the hydraulic motor 4 is mounted on the reducer housing 101 through the stator mounting stop 10101 and fixed to the corresponding bolt holes 10103 of the reducer housing 101 by long bolts 403. The rotor assembly 402 of the hydraulic motor 4 is mounted on the rotor mounting bearing chamber 10102. The shaft (output shaft) of the hydraulic motor 4 is coaxially connected to the input gear shaft 10501 of the hydraulic gear system 105.

[0062] The second mounting position includes a stator mounting stop 10104, a rotor mounting bearing chamber 10105, and several bolt holes 10106 arranged around the stator mounting stop 10104. The stator 404 of the travel motor 5 is mounted on the reducer housing 101 through the stator mounting stop 10104 and fixed to the corresponding bolt holes 10106 of the reducer housing 101 by long bolts 403. The rotor assembly 402 of the travel motor 5 is mounted on the rotor mounting bearing chamber 10105. The shaft of the travel motor 5 is coaxially connected to the input gear shaft 10401 of the travel gear system 104.

[0063] By sharing a housing with the travel reducer and the hydraulic reducer, and by providing a stator mounting stop, a rotor mounting bearing chamber, and bolt holes for fixing the motor stator on the side of the housing, the travel motor and the hydraulic motor can be integrated and mounted in parallel on the housing. This allows the housing to serve as the front cover for both the travel motor and the hydraulic motor, eliminating the need for a separate front cover for the motor in traditional forklift all-in-one assemblies. This effectively saves forklift installation space, significantly reduces the cost and weight of the drive assembly, and shortens its size.

[0064] like Figure 7 As shown, the non-cavity side of the travel reducer end cover 102 is provided with bearing holes 10203 for installing the bearings of each gear shaft of the travel gear system 104. The non-cavity side of the travel reducer end cover 102 is provided with a plurality of first radial ribs 10202. The first radial ribs 10202 are distributed radially around each bearing hole 10203. One end of each first radial rib 10202 is connected to the bearing hole 10203, and the other end is connected to the first bolt fixing hole 10201.

[0065] like Figure 8As shown, the hydraulic reducer end cover 103 is provided with bearing holes 10303 for installing bearings of each gear shaft of the hydraulic gear system 105. Several second radial ribs 10301 are provided on the non-cavity side of the hydraulic reducer end cover 103. The second radial ribs 10301 are distributed radially around each bearing hole 10303. One end of each second radial rib 10301 is connected to the bearing hole 10303, and the other end is connected to the second bolt fixing hole 10302.

[0066] By setting star-shaped intersecting radial ribs around the bearing bore with the center of the bearing bore as the center, the dynamic stiffness of the bearing can be significantly improved without significantly increasing the weight, and the noise transmitted from the gear excitation to the housing surface can be reduced.

[0067] like Figure 6 As shown, both the first chamber 108 and the second chamber 109 are provided with oil guide ribs 10107 and bearing oil inlets 10108. The oil guide ribs 10107 and bearing oil inlets 10108 are arranged according to the direction of gear oil flow, so that gear oil can smoothly and efficiently enter the bearing for lubrication.

[0068] Example 2

[0069] This embodiment provides a method for noise reduction design of an all-in-one integrated electric drive, including one or more of the following steps:

[0070] The design aims to reduce the resonance caused by the motor's pole slot number and its multiple frequency being close to the reducer's order.

[0071] The design aims to achieve a total overlap ratio of the primary gears ≥ 3 times the third set value, thereby reducing meshing stiffness and meshing fluctuation.

[0072] By micro-modifying the gears, the meshing misalignment of the first-stage gear is made ≤ the fourth set value x4 and the meshing misalignment of the second-stage gear is made ≤ the fifth set value x5, so as to reduce the meshing misalignment, make the meshing area more central, and reduce edge stress.

[0073] By micro-modifying the gears, the transmission error of the first-stage gear is made ≤ the sixth set value x6, the transmission error of the second-stage gear is made ≤ the seventh set value x7, and the transmission error of the third-stage gear is made ≤ the eighth set value x9, thereby reducing the amplitude of the dynamic excitation source.

[0074] The reducer housing is designed so that the first-order bending mode is greater than or equal to the ninth set value x9, so that the excitation frequency and the natural frequency are kept 1.4 times apart to avoid resonance.

[0075] By setting radial ribs around the reducer housing, the dynamic stiffness of the bearing bore is increased, and the deformation of the reducer housing under gear transmission error excitation is reduced, thereby reducing noise.

[0076] Wherein, the first setting value x1 is 2 and the second setting value x2 is 2;

[0077] The third setting value x3 is 4;

[0078] The fourth setting value x4 is 1 μm / mm, and the fifth setting value x5 is 1.5 μm / mm;

[0079] The sixth setting value x6 is 1 μm, the seventh setting value x7 is 2 μm, and the eighth setting value x8 is 3 μm;

[0080] The ninth setting x9 is 1500 Hz.

[0081] The dynamic stiffness of the bearing bore is ≥15000 N / mm.

[0082] Gear micro-modification involves making minute geometric modifications to the gear tooth surface, resulting in more uniform deformation of the gear under load, thereby reducing meshing impact and noise. Gear micro-modification methods include... Figure 9 As shown, this includes gear end face shaping, tooth direction helical shaping, tooth direction bulging, gear tooth tip and tooth root shaping, gear involute shaping, and gear tooth profile bulging.

[0083] The noise reduction design method of the all-in-one integrated electric drive of the present invention can avoid coupling with the number of motor tooth slots by reasonably designing the number of gear teeth, and effectively avoid vibration and noise problems caused by the excitation frequency being close to the meshing frequency. By setting radial ribs around the bearing hole with the center of the bearing hole as the center, the dynamic stiffness of the bearing can be greatly improved without significantly increasing the weight, and the noise transmitted from the gear excitation to the housing surface can be reduced, thereby significantly improving the NVH performance of the integrated electric drive.

[0084] Example 3

[0085] This embodiment provides an electric forklift, including the all-in-one integrated electric drive described in Embodiment 1.

[0086] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A multi-in-one integrated electric drive, characterized in that, The system includes a two-in-one high-speed reducer (1), a hydraulic motor (4), and a walking motor (5). The two-in-one high-speed reducer (1) includes a reducer housing (101), a walking reducer end cover (102), a hydraulic reducer end cover (103), a walking gear system (104), and a hydraulic gear system (105). The reducer housing (101) includes an integrally formed and mutually independent first housing (106) and a second housing (107). The walking reducer end cover (102) is fixedly connected to the first housing (106) to form a first chamber (108). The hydraulic reducer end cover (103) is fixedly connected to the second housing (107) to form a second chamber (109). The walking gear system (104) and the hydraulic gear system (105) are respectively disposed in the first chamber (108) and the second chamber (109) through bearings. The reducer housing (101) has a first mounting position and a second mounting position arranged in parallel on its side. The first mounting position includes a stator mounting stop (10101), a rotor mounting bearing chamber (10102), and several bolt holes (10103). The stator of the hydraulic motor (4) is mounted on the reducer housing (101) through the stator mounting stop (10101) and fixed to the corresponding bolt holes (10103) of the reducer housing (101) with long bolts. The rotor assembly mounting bearing of the hydraulic motor (4) is mounted in the rotor mounting bearing chamber (10102). The output shaft of the hydraulic motor (4) is connected to the input shaft of the hydraulic gear system (105). The gear shaft (10501) is coaxially connected; the second mounting position includes a stator mounting stop (10104), a rotor mounting bearing chamber (10105) and several bolt holes (10106). The stator of the walking motor (5) is mounted on the reducer housing (101) through the stator mounting stop (10104) and fixed to the corresponding bolt holes (10106) of the reducer housing (101) by long bolts. The rotor assembly mounting bearing of the walking motor (5) is mounted in the rotor mounting bearing chamber (10105). The output shaft of the walking motor (5) is coaxially connected to the input gear shaft (10401) of the walking gear system (104).

2. The all-in-one integrated electric drive of claim 1, wherein, The traveling gear system (104) includes an input gear shaft two (10401), an intermediate shaft one (10402), an intermediate shaft two (10403), and an output gear shaft two (10404) arranged in parallel. A gear three (z3) is mounted on the input gear shaft two (10401), a gear four (z4) and a gear five (z5) are mounted on the intermediate shaft one (10402), a gear six (z6) and a gear seven (z7) are mounted on the intermediate shaft two (10403), and a gear eight (z8) is mounted on the output gear shaft two (10404). Gear four (z4) and gear three (z3) mesh to form a primary transmission gear, and gear six (z6) and gear five (z5) mesh to form a secondary transmission gear. Gear 8 (z8) and gear 7 (z7) mesh to form a three-stage transmission gear, and the center lines of the axes of the input gear shaft 2 (10401), intermediate shaft 1 (10402) and intermediate shaft 2 (10403) are arranged in a triangle.

3. The all-in-one integrated electric drive according to claim 1, characterized in that, The end cap (102) of the walking speed reducer is fixedly connected to the first housing (106) through the first bolt fixing hole (10201).

4. The all-in-one integrated electric drive according to claim 3, characterized in that, The end cover (102) of the travel reducer is provided with a plurality of bearing holes (10203) corresponding to each gear shaft of the travel gear system (104). The end cover (102) of the travel reducer is provided with a plurality of first radial ribs (10202) around each bearing hole (10203). The first radial ribs (10202) are distributed radially around each bearing hole (10203) as the center, and one end of each first radial rib (10202) is connected to the bearing hole (10203), and the other end is connected to the first bolt fixing hole (10201).

5. The all-in-one integrated electric drive according to claim 1, characterized in that, The hydraulic reducer end cap (103) and the second housing (107) are fixedly connected through the second bolt fixing hole (10302).

6. The all-in-one integrated electric drive according to claim 5, characterized in that, The hydraulic reducer end cover (103) is provided with a plurality of bearing holes 2 (10303) corresponding to each gear shaft of the hydraulic gear system (105). The hydraulic reducer end cover (103) is provided with a plurality of second radial ribs (10301) around each bearing hole 2 (10303). The second radial ribs (10301) are distributed radially around each bearing hole 2 (10303) as the center, and one end of each second radial rib (10301) is connected to the bearing hole 2 (10303), and the other end is connected to the second bolt fixing hole (10302).

7. The all-in-one integrated electric drive according to claim 1, characterized in that, The first chamber (108) and the second chamber (109) are each provided with an oil guide rib (10107) and a bearing oil inlet hole (10108), which are arranged according to the direction of the gear oil flow.

8. The noise reduction design method for the all-in-one integrated electric drive according to claim 2, characterized in that, Includes one or more of the following steps: The design incorporates a first-order gear and motor order difference ≥ a first set value, and a second-order gear and motor order difference ≥ a second set value, to reduce resonance caused by the motor's pole slot number and its multiples being close to the reducer's order. The design aims to ensure that the total overlap ratio of the primary gears is greater than or equal to the third set value, thereby reducing meshing stiffness and meshing fluctuation. By micro-modifying the gears, the meshing misalignment of the first-stage gear is ≤ the fourth set value and the meshing misalignment of the second-stage gear is ≤ the fifth set value, so that the meshing area tends to be in the middle and the edge stress is reduced. By micro-modifying the gears, the transmission error of the first-stage gear is made ≤ the sixth set value, the transmission error of the second-stage gear is made ≤ the seventh set value, and the transmission error of the third-stage gear is made ≤ the eighth set value, thereby reducing the amplitude of the dynamic excitation source. The reducer housing is designed with a first-order bending mode ≥ the ninth set value to avoid resonance by keeping the excitation frequency away from the natural frequency.

9. The noise reduction design method for the all-in-one integrated electric drive according to claim 8, characterized in that, The first setting value is 2, and the second setting value is 2; The third setting value is 4; The fourth setting is 1 μm / mm, and the fifth setting is 1.5 μm / mm; The sixth setting is 1 μm, the seventh setting is 2 μm, and the eighth setting is 3 μm; The ninth setting is 1500 Hz.

10. The noise reduction design method for the all-in-one integrated electric drive according to claim 8, characterized in that, Also includes: By setting radial ribs around the reducer housing, the dynamic stiffness of the bearing holes is increased, and the deformation of the reducer housing under gear transmission error excitation is reduced.

11. The noise reduction design method for the all-in-one integrated electric drive according to claim 10, characterized in that, The dynamic stiffness of the bearing bore is ≥15000 N / mm.

12. An electric forklift, characterized in that, Includes the all-in-one integrated electric drive as described in any one of claims 1 to 7.

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