Automotive drive systems

Abstract

In a drive system for hybrid vehicles, the axial length is shortened to improve ease of installation in the vehicle, and it is also possible to develop a mechanical-electric CVT system using planetary gears. [Solution] The input shaft (10) can drive the intermediate shaft (24) via the counter shaft (18), the intermediate shaft (24) is connected to or can be connected to the output shaft (12), and can be connected to the input shaft (10) with a two-stage gear ratio, the output shaft (12) can be selectively connected to the fourth gear (12b) and fifth gear (12c) connected to the input shaft (10), and meshes with the low-speed driven gear (14c) and high-speed driven gear (14b) connected to the motor input shaft (16) driven by the second MG (22), the motor output shaft (16) can be selectively connected to the low-speed driven gear (14c) and high-speed driven gear (14b), and the counter shaft (18) can be connected to the high-speed driven gear (14b).

Description

Technical Field

[0004] , , , , , , ,

[0005] , , , , ,

[0001] The present invention relates to a drive device for an automobile, and more particularly to a drive device for a so-called hybrid automobile that includes an engine and a motor generator (hereinafter referred to as "MG") as power sources.

Background Art

[0002] Conventionally, as a drive device for this type of automobile, a configuration is known that includes two MGs (a first electric machine and a second electric machine), where one MG has a power transmission route for driving an automobile with a two-stage gear ratio and an engine has a power transmission route for driving an automobile with a plurality of gear ratios (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional drive device for an automobile, although it has both series-type and parallel-type hybrid drives, since the large-sized MG that mainly drives the automobile is arranged on the same axis as the input shaft, the axial length of the entire drive device tends to be long, and there is a problem in terms of mounting on the vehicle.

[0005] The problem to be solved is that due to the long axial length of the entire drive device, it is disadvantageous for mounting on a vehicle with a small vehicle width and lacks expandability. An object of the present invention is to provide an MG that mainly drives a vehicle parallel to the input shaft to improve the mounting property on the vehicle and solve the above problems, and further to enable the development into a mechanical-electric CVT system using a planetary gear.

Means for Solving the Problems

[0006] The automotive drive system of the present invention comprises an input shaft capable of receiving power from an engine, an output shaft, an intermediate shaft, a first motor-generator positioned on the same axis as the input shaft, a second motor-generator positioned parallel to the input shaft, and a first and second transmission mechanism, both having two gear ratios. The input shaft is connected to or connectable to the first motor-generator and can be connected to the output shaft via the first transmission mechanism, and the output shaft can be connected to the second motor-generator via the second transmission mechanism. The first transmission mechanism has a first gear integrated with the input shaft that can drive a second gear supported on an intermediate shaft positioned on the same axis as the input shaft via a counter shaft positioned parallel to the input shaft, and the intermediate shaft is connected to the output shaft. The second speed shift mechanism is characterized in that it is connectable or linkable, and selectively linkable with the input shaft and the second gear, and the output shaft is selectively linkable with the fourth and fifth gears supported on the output shaft in mesh with the second gear and the third gear which is integrated with the input shaft, and the second speed shift mechanism is positioned between the motor input shaft which is connected to the second motor generator and the motor output shaft which is connected to the output shaft, and the sixth and seventh gears which are integrated with the motor input shaft mesh with the low-speed driven gear and the high-speed driven gear which are positioned on the motor output shaft, the motor output shaft is selectively linkable with the low-speed driven gear and the high-speed driven gear, and the counter shaft is linkable with the high-speed driven gear. [Effects of the Invention]

[0007] As the automotive drive system of the present invention is configured as described above, it reduces the axial length of the drive system to improve its in-vehicle compatibility and can be developed into a drive system equipped with a mechanical-electric CVT. [Brief explanation of the drawing]

[0008] [Figure 1] This is a skeleton diagram showing the main parts of an automobile drive system according to Embodiment 1 of the present invention. [Figure 2] This diagram shows the arrangement of each axis in Example 1. [Figure 3] This is a diagram showing the operation table for Example 1. [Figure 4]This is a skeleton diagram showing the main parts of an automobile drive system according to Embodiment 2 of the present invention. [Figure 5] This is a diagram showing the operation table for Example 2. [Figure 6] This is a skeleton diagram showing the main parts of an automobile drive system according to Embodiment 3 of the present invention. [Figure 7] This is a velocity diagram of the planetary gear in Example 3. [Figure 8] This is a diagram showing the operation table for Example 3. [Figure 9] This is a skeleton diagram showing the main parts of an automobile drive system according to Embodiment 4 of the present invention. [Figure 10] This is a diagram showing the operation table for Example 4. [Modes for carrying out the invention]

[0009] Hereinafter, an automobile drive system according to an embodiment of the present invention will be described with reference to the figures based on an example. [Examples]

[0010] Figure 1 is a skeleton diagram of the main part of an automobile drive system according to Embodiment 1 of the present invention. The automobile drive system of Embodiment 1 has six shafts, including the MG, arranged as shown in Figure 2 when viewed from the left side of Figure 1. In Figure 2, the reference numeral of the shaft is written at the center of the shaft, and the outer diameter of the largest gear for each shaft is drawn with a thin line. All shafts are parallel to the input shaft 10, and the output shaft 12, motor output shaft 14, motor input shaft 16, counter shaft 18, and second MG 22 are arranged. Furthermore, the cross-section is drawn by unfolding from the bottom of Figure 1 in the order A to F indicated in Figure 2.Therefore, although the output shaft 12 and motor output shaft 14 are separated in Figure 1, in reality they are adjacent as shown in Figure 2, and the two are connected by a gear as shown by the thin dashed line in Figure 1.The circles in Figure 1 illustrate the arrangement of bearings, although their explanation is omitted.

[0011] The input shaft 10 is connected to the crankshaft 1a of the power source engine 1 via a damper 1b, and is connected to the first MG 20, which is located on the opposite axial side from the engine 1. An intermediate shaft 24 is located on the same axis as the input shaft 10 and is rotatable relative to it. A first drive gear 24a, which is integrated with the intermediate shaft 24, meshes with a driven gear 12a, which is integrated with the output shaft 12. The input shaft 10 and the intermediate shaft 24 can be connected via a counter shaft 18. That is, a first gear 10a, which is integrated with the input shaft 10, and a second gear 24b, which is rotatably supported on the intermediate shaft 24, mesh with a first counter gear 18a and a second counter gear 18b, respectively, which are integrated with the counter shaft 18. Further details will be described later.

[0012] The output shaft 12 has an integrated output gear 12h, which drives the wheels of the automobile via a mating gear (not shown). The output shaft 12 also rotatably supports a fourth gear 12b meshing with a third gear 10b integrated with the input shaft 10, and a fifth gear 12c meshing with a second gear 24b. By shifting the first sleeve 12d on the output shaft 12 in the axial direction, the output shaft 12 can be selectively coupled with the fourth gear 12b and the fifth gear 12c.

[0013] Here, the configuration and operation common to other sleeves described later will be explained using the first sleeve 12d as an example. Specifically, the first sleeve 12d is positioned radially outward of the first hub 12e, which is integrated with the output shaft 12, and is integrated with the first hub 12e in the rotational direction but is shiftable in the axial direction. The dog teeth 12f and 12g formed on the faces of the fourth gear 12b and fifth gear 12c facing the first sleeve 12d, respectively, selectively engage with one of them when the first sleeve 12d shifts. Figure 1 shows the neutral position where the first sleeve 12d is not engaged with either the dog teeth 12f or the dog teeth 24g. This group of gears, centered on the first sleeve 12d, which obtains a two-stage gear ratio between the input shaft 10 and the output shaft 12, constitutes the first gear shift mechanism 3 of the present invention. Furthermore, engagement between the first sleeve 12d and the dog teeth 12f and 12g is performed by controlling the rotational speed difference between them to be close to zero, and conversely, disengagement is performed by controlling the transmitted torque between them to be close to zero.

[0014] Thus, shifting the first sleeve 14d left and right in FIG. 1 is performed by a shift fork and an actuator not shown, but since these configurations are well-known, the figures and their descriptions are omitted. Also, for each of the subsequent sleeves, the entry and description of reference numerals such as hubs and dog teeth are omitted.

[0015] The intermediate shaft 24 can be selectively connected to the second gear 24b and the input shaft 10 by the second sleeve 24d. That is, when the second sleeve 24d is shifted to the left, it is connected to the second gear 24b that meshes with the second counter gear 18b of the counter shaft 18, and when shifted to the right, it is connected to the input shaft, respectively, obtaining a two-stage speed ratio between the input shaft 10 and the output shaft 12.

[0016] Next, the motor output shaft 14 has a second drive gear 14a integral with it that meshes with the driven gear 12a as described above and is connected to the output shaft 12. Also, the motor output shaft 14 has a third sleeve 14d. The motor output shaft 14 rotatably supports a high-speed driven gear 14b and a low-speed driven gear 14c, and can be selectively connected to them by the third sleeve 14d. The motor input shaft 16 integrates a fourth gear 16a that meshes with the high-speed driven gear 14b and a fifth gear 16b that meshes with the low-speed driven gear 14c. The fourth gear 16a meshes with the pinion 22a of the second MG22. By shifting the third sleeve 14d left and right, a two-stage speed ratio of low (low speed) and high (high speed) is obtained between the second MG22 and the output shaft 12, constituting the second speed change mechanism 4 of the present invention. This is also common to each of the subsequent embodiments.

[0017] The high-speed driven gear 14b has a fourth sleeve 14e and rotatably supports a sixth gear 14f that meshes with a third counter gear 18c integral with the counter shaft 18. By shifting the fourth sleeve 14e to the right, the high-speed driven gear 14b is connected to the sixth gear 14f, and the counter shaft 18 and the high-speed driven gear 14b are connected.

[0018] <Next, the operation and function of the automotive drive system shown in Figure 1 will be explained in accordance with the operation table shown in Figure 3. In the operation table in Figure 3, each drive mode described below is assigned to the vertical direction, and the operating status and gear ratio of the four sleeves and two MGs are assigned to the horizontal direction. Specifically, the first sleeve 12d is designated as S1, the second sleeve 24d as S2, the third sleeve 14d as S3, the fourth sleeve 14e as S4, the first MG20 as MG1, and the second MG22 as MG2. The arrows indicated in the table for each sleeve represent the shift direction of that sleeve. Note that arrows in parentheses indicate that even if shifted, they are not involved in power transmission. Furthermore, for the MGs, power generation is represented as G and driving as D. Note that the gear ratio value in EV mode is the rotational speed of the second MG22 / the rotational speed of the output shaft 12, and in HV mode high-efficiency drive, it is the rotational speed of the input shaft 10 / the rotational speed of the output shaft 12. Furthermore, the # shown in the table for the third sleeve 14d indicates that a shift of the third sleeve 14d may occur in that drive mode.

[0019] Although not shown in the diagram, the automotive drive system shown in Figure 1 is equipped with, in addition to the aforementioned shift fork and actuator, a battery, various sensors including accelerator pedal depression amount, a controller, an inverter, a shift lever, etc., as needed, and the following operations are basically performed based on the instructions of the controller.

[0020] The drive system shown in Figure 1 has two driving modes: "EV mode" when engine 1 is stopped and "HV mode" when engine 1 is running. In EV mode, the vehicle is driven as an EV (electric vehicle) by the second MG22, while in HV mode, there is a combination of electric CVT drive and high-efficiency drive, which will be described later.

[0021] First, let's explain the EV mode, which uses electricity stored in the battery as the power source. In EV mode, power is supplied from the battery to the second MG22 to drive the wheels, or the second MG22 is driven from the wheel side during braking, called regenerative braking, to generate electricity and charge the battery. As described above, the second transmission mechanism 4 provides a two-stage gear ratio between the second MG22 and the output shaft 12. For starting and low-speed driving, the gear ratio Lm (EL) is selected, and for high-speed driving, the gear ratio Hm (EH) is selected.

[0022] Switching between EL and EH is done by setting the torque of the second MG22 to 0. However, to avoid the drive torque or braking torque becoming temporarily 0, it is also possible to switch to the HV mode described later and then switch between the gear ratios Lm and Hm while driving in HV mode. Note that in EV mode, reverse is the same EL in the operation table, and the rotation direction of the second MG22 is the opposite of that in forward.

[0023] Next, we will explain the electric CVT (E-CVT) in HV mode. As described above, the input shaft 10 is connected to the first MG20, so power is supplied to the first MG20 from the battery to start the engine 1, and the engine 1 drives the first MG20 to generate electricity, which is then supplied to the second MG22 to drive the wheels in the same way as the EV mode described above. This is a hybrid drive generally called a series type, and since the gear ratio between the input shaft 10 and the output shaft 12 changes steplessly, it is an electric CVT. When the third sleeve 14d is shifted to the right, it is HL, and when it is shifted to the left, it is HH, and it is desirable to switch between HL and HH in the high-efficiency drive described later. Note that in HV mode, reverse is the same HL in the operation table, but the rotation direction of the second MG22 is the opposite of when it is moving forward.

[0024] Next, we will explain the high-efficiency drive in HV mode. In high-efficiency drive, when the E-CVT is running and a predetermined gear ratio is reached, the rotational speed difference between the sleeve and the dog teeth becomes zero, as mentioned above. By shifting the sleeve and engaging it with the dog teeth, the system switches to mechanical drive.

[0025] For example, if the vehicle starts in EV mode and the driver presses the accelerator pedal to accelerate rapidly, power is immediately supplied to the first MG20 to start engine 1 and transition to HL driving. In HL, as the gear ratio approaches 3.56, the rotational speed difference between the high-speed driven gear 14b and the fourth sleeve 14e approaches 0, so the fourth sleeve 14e is shifted to engage the two. This switches to 1st gear. At the same time, if the power generation and driving of the first MG20 and second MG22 are stopped, it becomes a purely mechanical drive, but it is also possible to have a so-called parallel hybrid drive where the first MG20 and second MG22 generate power or drive while driving in 1st gear. In 1st gear, the torque transmitted from the counter shaft 18 to the high-speed driven gear 14b is transmitted to the motor output shaft 14 via the motor input shaft 16 and the low-speed driven gear 14c, and drives the output shaft 12 via the second drive gear 14a and driven gear 12a. As is common to other high-efficiency drive positions, the 1st position allows for full-power drive from engine 1, regardless of the capacity of the 1st MG20 and 2nd MG22.

[0026] Next, when switching back to HL drive from 1st gear, the power generation and drive of the 1st MG20 and 2nd MG22 are restored, and the output of engine 1 is controlled as needed to bring the torque acting on the 4th sleeve 14e close to zero. Then, the 4th sleeve 14e is shifted to neutral, and the system switches to HL. Following acceleration in HL, the system can then be driven in 2nd to 6th gear as needed using the same method.

[0027] As can be seen in the operation table in Figure 3, the 2nd and 3rd modes, which are driven with high efficiency, are suitable for switching between Lm and Hm of the 3rd sleeve 14d. In other words, the switching between HL and HH is performed in the 2nd and 3rd modes when the 2nd MG22 is not being driven. Whether to perform the switch in the 2nd or 3rd mode should be decided according to the operating conditions, but as an example, the switch from HL to HH can be performed in the 3rd mode, and the reverse can be performed in the 2nd mode.

[0028] Now, let's explain the actuators. As mentioned above, there are four sleeves, but as can be seen in the operation table, the first sleeve 12d and the second sleeve 24d shift independently of each other and do not shift simultaneously. Therefore, the shift direction can be controlled by a single actuator for both sleeves. Also, the fourth sleeve 14e shifts when the third sleeve 14d is shifted, so both sleeves can be controlled by a single actuator. These are well known, so a detailed explanation will be omitted.

[0029] The above describes the operation of Example 1, and the following effects can be obtained in Example 1. As described above, four of the six high-efficiency drive stages are obtained between the input shaft 10, the counter shaft 14, and the output shaft 12, including the first gear shift mechanism 3. Furthermore, the components on the motor output shaft 14 that form the basis of the gear train length consist of four gears and two sleeves, which is one less gear than in the conventional example, so the axial length of the entire drive unit can be shortened by about 20 mm. In addition, because the input shaft 10 and the first MG20 are connected, the length of the MG on the extension of the input shaft 10 can be shortened compared to the conventional example. This is related to the fact that the first MG20, which is mainly for power generation, generally has a smaller capacity and can be smaller in size than the second MG22, which is mainly for driving. In particular, in the case of front-wheel drive vehicles, the part where the first MG20 is located is often close to the vehicle body, so it can be said that it is excellent for mounting in small vehicles. Furthermore, among the six high-efficiency drive stages (two stages x three, i.e., high / low switching of the first transmission mechanism 3, high / low switching of the second transmission mechanism 4, and high / low switching between the input shaft 10, intermediate shaft 24, and counter shaft 18), which is more than in conventional models, the advantage of the 1st and 2nd stages is that they can drive with the full power of engine 1 regardless of the capacity of the second MG22 when a large driving force is required. In addition, the 3rd to 6th stages can improve fuel efficiency during cruising compared to driving in series-type HV mode. Thus, the advantage is that there are many high-efficiency drive stages. [Examples]

[0030] Next, an automobile drive system according to Embodiment 2 of the present invention will be described. Figure 4 is a skeleton diagram of the main parts of the automobile drive system according to Embodiment 2 of the present invention. Here, the explanation will focus on the parts that differ from Embodiment 1, and parts that are substantially the same as those in Embodiment 1 will be given basically the same names and reference numerals and their explanations will be omitted. Although the shaft arrangement diagram of Embodiment 2, which corresponds to Figure 2, is omitted, the arrangement in Embodiment 2 is basically the same as in Figure 2.

[0031] The difference between Example 2 and Example 1 is that the counter shaft 18 and the high-speed driven gear 14b can be connected with a two-stage gear ratio. That is, the high-speed driven gear 14b rotatably supports the sixth gear 14f, which meshes with the first counter gear 18a, and the seventh gear 14g, which meshes with the second counter gear 18b, and can be selectively connected to the sixth gear 14f and the seventh gear 14g by the fourth sleeve 14e. In connection with this, the axial positional relationship between the first gear 10a and the third gear 10b on the input shaft 10 is reversed compared to Example 1, but there is no difference in function. Also, the components on the motor output shaft 14 that form the basis of the gear train length are five gears and two sleeves, which is the same as in the conventional example.

[0032] Next, regarding the operation and function of Example 2, the operation table corresponding to Figure 3 is shown in Figure 5. As described above, since the counter shaft 18 and the high-speed driven gear 14b can be connected with a two-stage gear ratio, the number of high-efficiency drive stages has increased to eight stages compared to Example 1, and the switching stages of the third sleeve 14d have changed to 3rd and 4th. In addition, the gear ratio of the eight-stage high-efficiency drive has changed significantly, with the gear ratio range expanding to 4.09 for 1st and 0.72 for 8th.

[0033] In addition to the effects described in Example 1, this embodiment offers the following advantages. Specifically, the number of high-efficiency drive gears has increased from 6 to 8 (2 gears x 4), widening the gear ratio range. As a result, the driving force of 1st and 2nd gears is greater, and the fuel efficiency improvement effect from 5th to 8th gears can also be expected to be expanded. [Examples]

[0034] Next, an automobile drive system according to Embodiment 3 of the present invention will be described. Figure 6 is a skeleton diagram of the main parts of the automobile drive system according to Embodiment 3 of the present invention. Here, the explanation will focus on the parts that differ from Embodiments 1 and 2, and parts that are substantially the same as those in Embodiments 1 and 2 will be given basically the same names and reference numerals and their descriptions will be omitted. Although the shaft arrangement diagram of Embodiment 3, which corresponds to Figure 2, is omitted, the arrangement in Embodiment 3 is basically the same as in Figure 2.

[0035] The first difference between Example 3 and Examples 1 and 2 is the connection relationship between the first MG20 and the input shaft 10, output shaft 12, and intermediate shaft 24. Specifically, the planetary gear 30 is located on the same axis as the input shaft 10 and is connected as follows. The planetary gear 30 is generally called a single-pinion type and has three rotating elements: a sun gear 32, a ring gear 34, and a carrier 38. The sun gear 32 is connected to the first MG20, the carrier 38 is connected to the intermediate shaft 24, and the ring gear 34 is integrated with the first drive gear 24a and connected to the output shaft 12. In other words, the input shaft 10 is connected to the first MG20 via the planetary gear 30, and the intermediate shaft 24 is connected to the output shaft 12 via the planetary gear 30.

[0036] The second difference between Example 3 and Example 1 is that the sixth gear 16f meshes with the first counter gear 18a. The other configurations are basically the same as in Examples 1 and 2.

[0037] Next, the operation of Embodiment 3 shown in Figure 6 will be explained with reference to the velocity diagram of the planetary gear 30 shown in Figure 7 and the operation table shown in Figure 8. The way the operation table in Figure 8 is drawn is basically the same as in Figure 3, but the S in the first MG20 represents stopping.

[0038] Here, although the velocity diagram shown in Figure 7 is well known, its outline will be explained. This velocity diagram shows the case of the HV mode described later. The vertical direction represents the rotational speed of each rotating member when the rotational speed of the input shaft 10 is set to 1. The horizontal direction shows each rotating member arranged at intervals corresponding to the tooth ratio ρ of the sun gear 32 to the ring gear 34 of the planetary gear 30, with a vertical line representing the velocity axis for each rotating member.

[0039] The symbols written above each speed axis in the speed diagram represent the sun gear 32 as S, the ring gear 34 as R, and the carrier 38 as C. Here, the tooth ratio ρ of the planetary gear 30 used to draw the speed diagram is 0.45, and the following explanations of each gear ratio are based on this.

[0040] In the velocity diagram, the vertical position of the intersection point between the velocity axis representing each rotating member and the velocity line (thick line) represents the rotational speed of each rotating member. Therefore, the speed of the ring gear 34 is the vertical position of the intersection point between the velocity axis (R) of the ring gear 34 and the velocity line drawn with a thick line, and the ratio of this to the rotational speed of the input shaft 10 (1) can be used as the gear ratio to be geometrically determined from the velocity diagram.

[0041] First, the EV mode is the same as in Examples 1 and 2, so we will omit its explanation. Next, the HV mode has two types: a continuously variable transmission drive called a mechanical-electric CVT with the action of planetary gears 30, which differs from Examples 1 and 2, and a high-efficiency drive similar to that in Examples 1 and 2.

[0042] Next, although the mechanical-electric CVT is well known, its overview will be explained. The carrier 38, driven from the intermediate shaft 24 via the input shaft 10 by the power of the engine 1, transmits its torque to the sun gear 32 and the ring gear 34. The torque acting on the ring gear 34 mechanically drives the output shaft 12. Meanwhile, the torque acting on the sun gear 32 generates electricity in the first MG 20, which supplies the resulting power to the second MG 22, which drives the output shaft 12 via the second transmission mechanism 4. In other words, the torque of the sun gear 32 is electrically transmitted to the output shaft 12. The rotational speed ratio between the input shaft 10 and the output shaft 12 changes steplessly according to the vehicle's drive load acting on the output shaft 12 and the engine's power. As the vehicle speed increases, the first MG 20 will eventually stop along with the sun gear 32. This is the 5th gear in Figure 8. In this case, the first MG20 stops and the electrical transmission described above becomes 0, so it is treated as mechanical transmission and classified as high-efficiency drive. However, as the speed of the first MG20 approaches 0, it automatically switches to high efficiency, so sleeve shifting is not required. As is well known, when the vehicle is stopped, the first MG20 is rotated in reverse in the HL state shown in Figure 8, and when the vehicle is in motion, the first MG20 is used to generate power regardless of the drive mode. Also, in HV mode, reverse is the same HL in the operation table, but the rotation direction of the second MG22 is the opposite of that in forward.

[0043] Furthermore, as in Examples 1 and 2, the second MG22 is driven in two stages, low speed (L) and high speed (H), by the second transmission mechanism 4. In this embodiment, in addition, there is a two-stage shift between the input shaft 10 and the carrier 38 by the shift of the third sleeve 24d, resulting in four possible combinations of the two gear ratios. However, in reality, the ratio of L to L (HL) and H to H (HH) is high, so the combination of H in the second transmission mechanism 4 and L in the third sleeve 24d is designated as H-Lh. The gear ratio Lc (speed of input shaft 10 / speed of carrier 38) due to the left-side shift of the third sleeve 24d is set to 1.8. As can be seen in Figure 8, this is why the speed of the carrier 38, indicated by the speed axis C, is at points 1 and 1 / Lc. The 1st and 2nd are only 1 / Lc, while the 3rd and 4th are shown with two speed lines: a solid line passing through 1 / Lc and a dashed line passing through Hc, which is speed 1.

[0044] Thus, in the continuously variable transmission drive from HL through H-Lh to HH, as in Examples 1 and 2, each sleeve is shifted when a predetermined gear ratio is reached to perform high-efficiency drive, and the second sleeve 24d and the third sleeve 14d are switched at individual high-efficiency drive positions. Overall, as in Examples 1 and 2, there are points where high-efficiency drive is possible despite it being a continuously variable transmission. The difference is that, in Examples 1 and 2, the drive other than the high-efficiency drive is a series-type electric CVT, and the driving force is only the torque of the second MG 22, whereas in this embodiment, it is a mechanical-electric CVT, and the driving force is the torque of the second MG 22 plus the torque acting on the ring gear 38. The torque acting on the ring gear 38 is Lc{1 / (1+ρ)} in HL, which is 1.24 for the gear ratio Lc and tooth ratio ρ described above, and 1 / (1+ρ) in HH, which is similarly 0.69, when the torque of the input shaft 10 is set to 1.

[0045] In addition to the effects described in Examples 1 and 2, this embodiment offers the following advantages. Specifically, the HV mode is based on a mechanical-electric CVT, which has the advantage of being able to increase the driving torque. Furthermore, since the power transmission efficiency increases according to the ratio of power transmitted mechanically, fuel efficiency improves, especially during cruising with a small gear ratio, even with drives other than high-efficiency drives. In addition, 1st gear is a gear ratio equivalent to 1st gear in a typical automatic transmission (AT), allowing for full power driving of engine 1.

[0046] Furthermore, although not shown in the diagram, it is well known that if the output shaft 12 drives the front wheels of the automobile, a small MG for rear-wheel drive and a separate output shaft for the rear wheels, distinct from the output shaft 12, can be provided to create a four-wheel drive system. In that case, because the ratio of electrical power transmission described above is low, during cruising such as HH, when the second MG22 is driven in a low-load, low-efficiency state, the third sleeve 14d can be set to neutral to stop the second MG22, and the electricity generated by the first MG20 can be supplied to the MG for rear-wheel drive, thereby allowing it to function as a mechanical-electric CVT. This reduces energy loss when rotating the large-capacity second MG22 and improves fuel efficiency. This effect is similar in Examples 1 and 2, but Example 3, which is equipped with planetary gears 30 and has a high ratio of power generation by the first MG20 at low rotation speeds during cruising, shows a greater improvement in fuel efficiency. [Examples]

[0047] Next, an automobile drive system according to Embodiment 4 of the present invention will be described. Figure 9 is a skeleton diagram of the main parts of the automobile drive system according to Embodiment 4 of the present invention. Here, the parts that differ from Embodiment 3 will be described in detail, and parts that are substantially the same as those in Embodiment 3 will be given basically the same names and reference numerals, and their descriptions will be omitted.

[0048] The difference between Example 4 and Example 3 is that, as in Example 2, the counter shaft 18 and the high-speed driven gear 14b can be connected with a two-stage gear ratio. Other aspects, including the planetary gear 30, are the same as in Example 3, as shown in Figure 9, and therefore the explanation is omitted. The gear ratio Lc is set to 1.80, and the gear ratio ρ is set to 0.5.

[0049] Next, regarding the operation and function of Example 4, an operation table corresponding to Figure 8 is shown in Figure 10. As described above, compared to Example 3, the connection between the counter shaft 18 and the high-speed driven gear 14b is made possible with two gear ratios, so the number of high-efficiency drive stages has increased to seven, and the position for switching the second sleeve 24d has changed to 4th and 5th. In addition, the gear ratio of the seven high-efficiency drive stages has changed significantly, with 1st being 4.84 and 8th being 0.68, thus widening the gear ratio range.

[0050] In addition to the effects described in Example 3, this embodiment offers the following advantages. Specifically, because the number of high-efficiency drive gears has increased from 5 to 7, the gear ratio range has widened, resulting in greater driving force in 1st and 2nd gear, and also expanding the fuel efficiency improvement effect from 5th to 7th gear.

[0051] The above describes the various embodiments of the present invention. However, as is common to all embodiments, although a diagrammatic explanation is omitted, if a connecting mechanism such as a sleeve is provided between the input shaft 10 and the engine 1, and the two can be separated, the input shaft 10 can rotate even when the engine 1 is stopped. Therefore, in the sleeve connection relationship described as high-efficiency drive in each embodiment, it becomes possible to drive in EV mode, and the first MG20 can also participate in the drive in addition to the second MG22. This has the effect of providing a large driving force when used in plug-in hybrid vehicles with a large battery capacity and a high proportion of EV driving.

[0052] The automotive drive system of the present invention can be implemented in a manner that combines control features such as optimal setting of the distance between each axle and the gear ratio, optimization of the bearing arrangement, and a method for selecting the drive mode, based on the general knowledge of those skilled in the art. [Industrial applicability]

[0053] The automotive drive system of the present invention can be applied to passenger cars and commercial vehicles that require smooth gear changes, particularly low running costs, and reduced environmental impact. However, it is not limited to these vehicles and can be applied to a variety of vehicles utilizing internal combustion engines and motor-generators. [Explanation of Symbols]

[0054] 1 Engine 3. First transmission mechanism 4. Second transmission mechanism 10 input axes 12 Output shafts 14 Motor output shaft 16 Motor input shaft 18 Counter axis 20. First Motor Generator (MG1) 22. Second Motor Generator (MG2) 30 Planetary gears

Claims

1. An input shaft capable of receiving power from the engine, Output shaft and, Intermediate axis and A first motor-generator is positioned on the same axis as the aforementioned input shaft, A second motor-generator is arranged parallel to the aforementioned input shaft, The first and second transmission mechanisms each have two gear ratios, Equipped with, The input shaft is connected to or connectable to the first motor-generator and can also be connected to the output shaft via the first transmission mechanism. The output shaft is connectable to the second motor-generator via the second transmission mechanism, The first gear shift mechanism is such that a first gear, integrated with the input shaft, can drive a second gear, which is supported on the intermediate shaft located on the same axis as the input shaft, via a counter shaft arranged parallel to the input shaft; the intermediate shaft is connected to or can be connected to the output shaft, and can be selectively connected to the input shaft and the second gear; and the output shaft can be selectively connected to a fourth gear and a fifth gear, which mesh with the second gear and a third gear integrated with the input shaft and are supported on the output shaft. The second gear shift mechanism is positioned between a motor input shaft connected to the second motor generator and a motor output shaft connected to the output shaft, and a sixth gear and a seventh gear, which are integrated with the motor input shaft, mesh with a low-speed driven gear and a high-speed driven gear positioned on the motor output shaft, the motor output shaft can be selectively connected to the low-speed driven gear and the high-speed driven gear, and the counter shaft can be connected to the high-speed driven gear.

2. The automobile drive device according to claim 1, characterized in that it has a two-stage speed change mechanism between the counter shaft and the high-speed driven gear.

3. The automobile drive system according to claim 1 or 2, characterized in that the input shaft is connected to the first motor-generator and the intermediate shaft is connected to the output shaft.

4. The automobile drive device according to claim 1 or 2, characterized in that a planetary gear consisting of three rotating elements, a sun gear, a ring gear, and a carrier, is provided on the same axis as the input shaft, the sun gear is connected to the first motor-generator, the carrier is connected to the intermediate shaft, and the ring gear is connected to the output shaft.

5. The automobile drive system according to any one of claims 1 to 4, wherein the output shaft drives the front wheels of the automobile, and the system includes a second output shaft having a third motor-generator capable of driving the rear wheels with the third motor-generator, and in cruising conditions, the second transmission mechanism is set to neutral and the power generated by the first motor-generator is supplied to the third motor-generator.

Images