High-efficiency oil cooling speed reducer

Abstract

The utility model relates to the technical field of oil cooling speed reducers, in particular to a high-efficiency oil cooling speed reducer which comprises a shell and an oil cooler, an oil pump and an oil pool are arranged at the bottom of the shell, an outlet of the oil pump is communicated with an inlet of the oil cooler, and an inlet of the oil pump is communicated with the oil pool. A novel lubricating and cooling mode is provided, the key point of efficiency improvement is that the gear does not make contact with bottom oil as much as possible during working, oil stirring loss is reduced, the oil pump can be prevented from sucking air under all angle working conditions through an oil pool structure and an oil suction opening of the oil pump, and the service life of the gear is prolonged. And meanwhile, the pipe diameter is adjusted in a matched mode to meet the requirement for oil quantity distribution of all positions, the efficiency of the oil-cooled speed reducer can be improved, the efficient interval can be expanded, then the overall dynamic efficiency is improved, the endurance mileage of the whole vehicle is increased, and the comprehensive efficiency can reach 98% or even higher.

Description

Technical Field

[0001] The utility model relates to the technical field of oil-cooled reducers, in particular to a high-efficiency oil-cooled reducer. Background Art

[0002] At present, the main constraint of new energy vehicles is still range anxiety. All OEMs are also doing their best to improve the range. There are two directions for improvement: one is to increase the power capacity, and the other is to reduce losses and improve efficiency. The first direction has been significantly improved. Some pure electric models can already achieve an actual range of 1,000 km at high speed, which has exceeded the range of many fuel vehicles. The second direction still has room for improvement, such as reducing wind resistance and improving total power efficiency.

[0003] In order to improve the efficiency of oil-cooled powertrains, the reducers on the domestic market are currently mainly the most conventional ones. However, with the development and gradual improvement of market demand, more types of reducers have been derived based on the simplest reducers, such as integrated oil-cooled powertrain reducer. This type of reducer has high stability and strong adaptability, and is widely used in some well-known car models.

[0004] The actual measured results of the current reducer efficiency map are as follows Figure 1 The measured efficiency map of a certain type of reducer shows that the areas with high efficiency are dark in color and the areas with low efficiency are light in color. The overall efficiency in the map is 97.1%, which is higher than the 96.5% overall efficiency of the water-cooled powertrain. However, it can still be seen that the efficiency is relatively low in the low speed and low torque areas. If we can improve the efficiency in these areas, it will greatly improve the overall efficiency of the reducer. In addition, in the actual use of the vehicle, the main operating points are often concentrated in these areas.

[0005] We analyzed the energy loss in the low speed and low torque areas. In the low speed area, since the lubricating oil has not been completely stirred into the inner chamber, the gears are still soaked in the reducer oil, which is extremely difficult, just like walking in a swimming pool, so a large part of the efficiency loss is due to the stirring of the oil. In high-speed and low-torque conditions, since the drag torque is only related to the rotational inertia of the gears, the main reason for the inconsistent efficiency under the same torque and different speed conditions is that the energy is given to the stirring of the oil and the bearing oil seal to overcome the friction and do work, and the friction of the bearing oil seal is inevitable, so the efficiency improvement point is mainly to reduce the stirring of the oil loss. For example, in the oil-cooled electric drive reducer assembly with publication number CN115076347A, the lubricating oil only needs to immerse 1 / 5 of the main reduction gear, which can greatly reduce the stirring of the oil loss. Utility Model Content

[0006] In order to solve the above technical problems, the embodiment of the utility model provides a high-efficiency oil-cooled reducer, so as to provide a new lubrication and cooling method, which can improve the efficiency of the oil-cooled reducer.

[0007] This is achieved through the following technical solutions:

[0008] A high-efficiency oil-cooled reducer comprises a housing and an oil cooler. An oil pump and an oil pool are arranged at the bottom of the housing. The oil pump outlet is connected to the oil cooler inlet, and the oil pump inlet is connected to the oil pool. The lubricated oil flows back to the oil pool and enters the oil pump after being filtered.

[0009] Further preferably, the housing includes a front housing and a rear housing, the front housing and the rear housing form a shell cavity, the shell cavity is equipped with an input shaft assembly, an intermediate shaft assembly and a differential assembly, the input shaft assembly is drivingly connected to the motor output shaft, and the oil cooler outlet is connected to the input shaft assembly, the intermediate shaft assembly, the differential assembly and the motor stator and rotor.

[0010] Further preferably, the oil pool is arranged below the oil pump, an oil suction pipe is arranged between the oil pump inlet and the oil pool, and the bottom end of the oil suction pipe is the oil suction port.

[0011] Further preferably, the oil cooler is arranged on the top of the front housing, and an oil pump outlet oil passage connecting the oil pump outlet and the oil cooler inlet is arranged in the front housing.

[0012] Further preferably, the diameter of the oil channel from the oil cooler to the motor stator is 9.17 cm, the diameter of the oil channel to the rotor is 2.12 cm, the diameter of the oil channel to the reducer bearing is 0.22 cm-0.33 cm, the diameters of the oil channels to the two gear pairs are 1.16 cm and 1.44 cm respectively, and the diameter of the oil channel to the differential is 0.59 cm.

[0013] Further preferably, rib plates are provided above the oil pool and between the intermediate shaft assembly and the differential assembly, respectively.

[0014] Beneficial effects of the utility model:

[0015] 1) The utility model provides a new type of lubrication and cooling method, which can improve the efficiency of the oil-cooled reducer and expand the high-efficiency range, thereby improving the overall power efficiency and the vehicle's cruising range, and can achieve a comprehensive efficiency of 98% or even higher.

[0016] 2) The key point of improving efficiency of the utility model is that the gears try not to contact the bottom oil when working, reducing oil stirring loss. The oil pool structure and the oil suction port of the oil pump can ensure that the oil pump will not suck empty under all working angles. At the same time, the pipe diameter is matched and adjusted to meet the oil distribution at each position, thereby improving the overall efficiency.

[0017] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the accompanying drawings:

[0019] Figure 1 This is the actual measured result diagram of the efficiency map of the existing reducer.

[0020] Figure 2 It is a schematic diagram of the stable liquid level height in the high-efficiency zone of the existing reducer oil.

[0021] Figure 3 It is a schematic diagram of the oil circuit of the oil-cooled powertrain.

[0022] Figure 4 The utility model is a schematic front view of the interior of a front shell of a high-efficiency oil-cooled reducer.

[0023] Figure 5 The utility model is a three-dimensional schematic diagram of the interior of a front housing of a high-efficiency oil-cooled reducer.

[0024] Figure 6 The utility model is a three-dimensional structural schematic diagram of a high-efficiency oil-cooled reducer.

[0025] Figure 7 The utility model is a schematic front view of the interior of a rear housing of a high-efficiency oil-cooled reducer.

[0026] Figure 8 The utility model is a schematic diagram of an oil cooler of a high-efficiency oil-cooled reducer.

[0027] Fig. 9 The utility model is a schematic diagram of a rotor of a high-efficiency oil-cooled reducer.

[0028] Fig.10 The utility model is a schematic diagram of an oil pump of a high-efficiency oil-cooled reducer.

[0029] 1-front housing, 2-rear housing, 3-input shaft assembly, 4-intermediate shaft assembly, 5-differential assembly, 6-oil pump, 61-oil pump outlet, 62-oil pump inlet, 7-oil cooler, 71-oil cooler inlet, 72-oil cooler outlet, 8-oil sump, 9-oil suction pipe, 91-oil suction port, 10-oil pump outlet oil channel, 11-rotor, 12-small hole, 13-rib plate. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] By observing the lubrication test of the reducer, taking the horizontal road condition as an example, we can always find that when the reducer is in high-efficiency speed condition, the height of the oil level at the bottom of the existing reducer is often at the tangent position of the lowest axis, such as Figure 2 The middle horizontal line is the stable liquid level of the existing reducer oil high efficiency area, so why is it always in this area? The reason is that the gears of the reducer have a strong oil carrying capacity, and the gears in the lower area cannot stir. If the gears of the reducer do not stir the lubricating oil, the oil stirring loss will disappear, thus improving efficiency.

[0032] However, if the oil stirring loss is completely eliminated, it means that the gear and the oil surface are separated, and passive lubrication cannot be performed. Therefore, this high-efficiency solution can only be applied to oil-cooled reducers with active lubrication. In addition, since the gears and bearings require continuous lubrication with lubricating oil, this solution requires a full-contact active lubrication solution, and the reducer cannot have air suction under various working conditions, which puts extremely high demands on the design. However, after the design is completed and the ideal effect is achieved, the reducer oil is directly sprayed on the gear meshing position (two places), the bearing chamber (six places), the inside of the differential (one place), and the stator and rotor of the powertrain (oil-cooled powertrain, multiple lubrication and cooling points). Each position is fully lubricated and there is no extra oil stirring torque loss, and the efficiency will be greatly improved.

[0033] So how to achieve this high efficiency solution? Taking oil-cooled powertrain as an example, most oil circuit solutions are as follows: Figure 3 Oil circuit scheme is shown. Figure 3 The route can be divided into three parts. The first part of the leftmost large box is the oil suction part, as shown in the middle large box in the figure. The second part is the lubrication part, as shown in the rightmost large box in the figure. The third part is the reflux part. In the first part of the oil suction part, based on the high-efficiency solution, we mainly need to ensure that there is no air suction and the oil filter is unobstructed. The second part of the lubrication part requires matching the oil volume of each lubrication position so that each position has sufficient oil.

[0034] Taking the most complex oil-cooled powertrain solution as an example (200kw, oil pump peak flow 16L / min), in the first part, in order to ensure that the oil pump does not suck air, the position of the oil pump is crucial. In the existing technical solution, although the 30% slope of the front and rear tilt can ensure that there is no suction, and the 20% slope of the left and right tilt angle can not suck air, but after reaching a certain angle, the oil sucked by the oil pump contains a lot of bubbles, which has a great impact on the lubrication and cooling effect, and cannot meet the requirements for the high-efficiency solution. Since the high-efficiency solution does not have splash lubrication, a better oil pump solution and a better oil suction port are needed.

[0035] The reducer includes a housing, in which an input shaft assembly 3, an intermediate shaft assembly 4 and a differential assembly 5 are installed. The housing includes a front housing 1 and a rear housing 2. The front and rear housings 2 are combined to form the entire outer shell of the reducer. The input shaft assembly 3, the intermediate shaft assembly 4 and the differential assembly 5 are installed in the shell cavity formed by the front housing 1 and the rear housing 2. The input shaft assembly 3 is drivingly connected to the output shaft of the motor. An oil pump 6 is connected to the bottom of the housing, and an oil cooler 7 is arranged on the top of the housing. The oil pump outlet 61 is connected to the oil cooler inlet 71, and the oil cooler outlet 72 is connected to all lubricated parts in the reducer. The lubricated oil flows back to the oil pump inlet 62 for filtration and circulation. The above are all prior arts. For the structure and working principle of other parts of the reducer, reference can be made to the prior art and will not be repeated here.

[0036] In this embodiment, we optimize the existing design, adjust the structure at the bottom, and lower the oil suction port 91, such as Figure 4-10 As shown in the high efficiency shell solution, Figure 4-7 In the figure, an oil pool 8 is arranged at the bottom of the shell, and the oil pool 8 is arranged below the oil pump 6. An oil suction pipe 9 is arranged between the oil pump inlet 62 and the oil pool 8. The bottom end of the oil suction pipe 9 is an oil suction port 91. The oil pump outlet 61 is connected with the oil cooler inlet 71 through the oil pump outlet oil channel 10 arranged in the front shell 1. The purpose of adding this part is to allow the oil pump suction port 91 to continue to be lowered to ensure that at any angle and any working condition, the oil pump 6 has sufficient oil to pump to various places for lubrication, and the oil suction port 91 is in the middle of the reducer in the Y direction, so it can ensure both forward and backward tilting lubrication and left and right tilting lubrication. It is estimated that it can work under forward and backward tilting of 45%, left and right tilting of 30% and even various combined working conditions.

[0037] In the second part, during the structural design process of this part, all points of the reducer that need lubrication and the stator and rotor 11 need to be actively lubricated, including the stator, rotor 11, six bearings, two gear meshing points and the inside of the differential. The matching of oil volume is crucial. By comparing the heat generation of each point in the powertrain, we have determined that the stator requires a maximum oil volume of about 9L / min, the rotor 11 requires a maximum oil volume of about 2L / min, each bearing of the reducer needs to be greater than 0.2L / min, the gear pair requires 1L / min, and the differential requires 0.5L / min.

[0038] Based on this oil quantity requirement, we can extract the oil circuit of the reducer solution, and after extraction, perform CFD simulation to obtain the oil quantity distribution at each position. It should be noted that since the oil cooling distribution design can actually be understood as a pipe diameter matching design, that is, adjusting the pipe diameter at each location can adjust the oil quantity distribution at each location, so we can adjust the pipe diameter matching at each location of the solution in combination with the actual machining capabilities. After adjustment, the oil quantity at each location meets the above flow requirements, which can meet the normal reducer cooling and lubrication requirements. Based on this, the following design simulation oil quantity matching results are obtained: the diameter of the stator oil channel from the oil cooler 7 to the stator part is 9.17㎝, the diameter of the rotor oil channel to the rotor 11 part is 2.12㎝, the diameter of the bearing oil channel to the reducer bearing is 0.22㎝-0.33㎝, such as 0.22㎝, 0.25㎝, 0.26㎝, 0.29㎝, 0.31㎝, 0.33㎝, the diameters of the gear pair oil channels to the two gear pair parts are 1.16㎝ and 1.44㎝ respectively, and the diameter of the differential oil channel to the differential part is 0.59㎝.

[0039] In the present application, the oil circuit from the oil cooler 7 to the above-mentioned parts requiring lubrication can adopt the oil circuit design of the existing technology, or the following partial design can be adopted. The output point of the stator oil circuit is preferably arranged at the upper part, that is, at the top of the stator. This position is more conducive to the oil flowing quickly in the oil channel of the motor housing under the action of gravity to take away more heat. The output point of the rotor 11 oil circuit can only be located inside the rotor 11 shaft. Due to the high-speed rotation of the rotor 11 shaft, the oil can be thrown out to various places inside the motor. The rotor 11 is hollow inside. The oil is input into the motor rotor 11 through the reducer oil circuit and then thrown out through the small hole 12 on the right.

[0040] In addition, for the design of the oil passages in various parts of the reducer, the oil pump 6 is located at the bottom of the reducer, while the oil cooler 7 is relatively arbitrary and can be designed according to the specific situation. Taking the reducer mentioned in the previous article as an example, the oil cooler 7 is designed to be placed directly above the input shaft assembly 3. Since the reducer housing is a die-casting, the oil circuit can be realized by die-casting + machining. This method has relatively lower costs, good position assurance, and high reliability. The oil from the oil pump 6 can enter the oil cooler 7 through the oil pump outlet oil passage 10 on the front housing 1.

[0041] From the oil cooler 7 to each bearing position, the key points of the oil circuit must be determined first. Since the reducer is divided into a motor-end housing and a reducer-end housing, and the two housings are independently processed and manufactured, in order to minimize sealing points and enhance reliability, the reducer oil circuit needs to be divided into a motor-end oil circuit and a reducer-end oil circuit. Because the motor stator and the motor-end housing are directly connected, the motor-end housing oil circuit needs to be compatible with the stator oil outlet. Since the motor stator is in high-speed rotation, the rotor 11 oil circuit output port needs to have a certain gap with the rotor 11, but the gap cannot be too large to avoid pressure release, and if it is designed at the input shaft motor-end bearing, a closed bearing chamber needs to be made, which is not friendly to bearing chip removal, so the rotor 11 oil circuit outlet needs to be designed in the reducer-end housing oil circuit.

[0042] In the third part, we need to design the oil return circuit so that the oil return circuit is unobstructed and the oil can smoothly return to the oil suction port 91. Ribs 13 are respectively provided above the oil pool 8 and between the intermediate shaft gear and the differential gear. The ribs 13 at various positions wrap the gears to separate the oil circuit and the gears. The rotation of the gears will not affect the return of the oil, and the return of the oil will not contact the high-speed rotating gears, so there will be no torque loss.

[0043] Finally, the definition of oil volume is crucial. If the oil volume is defined as too much, a large amount of oil will still be deposited at the bottom after the oil pump works, which will cause the oil and gear to contact and affect efficiency. If the oil volume is defined as too little, there will be too little oil at the bottom. Under the extreme inclination angles of front, back, left, and right, the oil pump 6 will suck air or a small amount of air. Since the lubrication of the gear bearings depends entirely on the active pumping of the oil pump, this situation is fatal to the high-efficiency solution. The definition of the oil pump 6 is the total volume V = V oil channel + V oil pool 8. The advantage of this definition is that after the oil pump works, the oil channel is full of oil, and the oil level of the reducer drops below the lower edge of the gear, so it can work without resistance at any time. The oil continues to spray the gear shaft meshing position, bearing position, and differential position, and the main friction pair has enough oil lubrication. Analyzing the internal volume of the reducer, the volume of the oil channel is 0.467L, and the volume of the oil pool 8 is about 0.8L, so the total oil volume is 1.267L rounded to 1.3L. The fuel volume of powertrains with the same power platform on the market is generally 1.5L-1.8L, which is relatively small among powertrains of the same level, further reducing the cost of the entire vehicle.

[0044] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A high-efficiency oil-cooled reducer, characterized in that: The invention comprises a housing and an oil cooler (7). An oil pump (6) and an oil pool (8) are arranged at the bottom of the housing. The oil pump outlet (61) is connected to the oil cooler inlet (71), and the oil pump inlet (62) is connected to the oil pool (8). The lubricated oil flows back to the oil pool (8) and enters the oil pump after being filtered.

2. A high-efficiency oil-cooled reducer according to claim 1, characterized in that: The housing comprises a front housing (1) and a rear housing (2), wherein the front housing (1) and the rear housing (2) form a housing cavity, wherein an input shaft assembly (3), an intermediate shaft assembly (4) and a differential assembly (5) are installed in the housing cavity, wherein the input shaft assembly (3) is drivingly connected to an output shaft of a motor, and an outlet of the oil cooler (7) is connected to the input shaft assembly (3), the intermediate shaft assembly (4), the differential assembly (5) and a stator and rotor of the motor.

3. A high-efficiency oil-cooled reducer according to claim 2, characterized in that: The oil pool (8) is arranged below the oil pump (6), an oil suction pipe (9) is arranged between the oil pump inlet (62) and the oil pool (8), and the bottom end of the oil suction pipe (9) is an oil suction port (91).

4. A high-efficiency oil-cooled reducer according to claim 3, characterized in that: The oil cooler (7) is arranged on the top of the front housing (1), and an oil pump outlet oil passage (10) connecting the oil pump outlet (61) and the oil cooler inlet (71) is arranged in the front housing (1).

5. The high-efficiency oil-cooled reducer according to claim 1 is characterized in that: The diameter of the oil passage from the oil cooler (7) to the motor stator is 9.17 cm, the diameter of the oil passage to the rotor (11) is 2.12 cm, the diameter of the oil passage to the reducer bearing is 0.22 cm-0.33 cm, the diameters of the oil passages to the two gear pairs are 1.16 cm and 1.44 cm respectively, and the diameter of the oil passage to the differential is 0.59 cm.

6. A high-efficiency oil-cooled reducer according to claim 2, characterized in that: Rib plates (13) are respectively provided above the oil pool (8) and between the intermediate shaft assembly (4) and the differential assembly (5).

Images