Vehicle drive device

Abstract

To provide a vehicle drive device including a braking device capable of achieving various functions.SOLUTION: A rotary electric machine; a differential gear mechanism which is connected to the left and right wheels and transmits a driving force from the rotary electric machine to the wheels; a first braking device which is disposed between the differential gear mechanism and the left-side wheel in the power transmission path and generates a braking force with respect to the rotation of the left-side wheel; A vehicle drive device includes a second braking device that generates a braking force against rotation of a right wheel, and a case that supports a rotary electric machine, a differential gear mechanism, a first braking device, and a second braking device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle drive device. [Background technology]

[0002] A technology is known in which a braking device consisting of an electromagnetic clutch or the like is arranged on the same axis as a rotating electric machine that is provided on a separate axis from the differential gear mechanism, and the braking device is activated when the rotating electric machine stops, thereby maintaining the vehicle in a stopped state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-72402 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described conventional technology, the brake device provided coaxially with the rotating electric machine operates only when the rotating electric machine is stopped, and the function thereof is therefore limited.

[0005] Therefore, in one aspect, an object of the present disclosure is to provide a vehicle drive device equipped with a braking device that can achieve a variety of functions. [Means for solving the problem]

[0006] In one aspect, a rotating electric machine; a differential gear mechanism connected to left and right wheels and configured to transmit driving force from the rotating electric machine to the wheels; a first braking device disposed in a power transmission path between the differential gear mechanism and the left wheel, the first braking device generating a braking force against rotation of the left wheel; a second braking device disposed in a power transmission path between the differential gear mechanism and the right wheel, the second braking device generating a braking force against rotation of the right wheel; A vehicle drive device is provided that includes the rotating electric machine, the differential gear mechanism, and a case that supports the braking device. [Effects of the Invention]

[0007] According to one aspect, the present disclosure makes it possible to provide a vehicle drive device equipped with a braking device that can realize a variety of functions. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic top view showing a state in which a vehicle drive device is mounted in a vehicle. [Figure 2] 1 is a skeleton diagram showing a vehicle drive device according to an embodiment of the present invention; [Figure 3] FIG. 2 is a schematic diagram showing an example of an oil supply system applicable to the present embodiment. [Figure 4] FIG. 10 is a skeleton diagram showing a vehicle drive device according to another embodiment. [Figure 5] FIG. 10 is a schematic cross-sectional view of a vehicle drive device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Furthermore, in the drawings, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0010] In the following description, the directions of each component represent the directions when the component is assembled in the vehicle drive device 100. Furthermore, terms relating to the dimensions, arrangement direction, arrangement position, etc. of each component are concepts that include differences due to tolerances (tolerable manufacturing tolerances). Direction A (see FIG. 1, etc.) corresponds to the vehicle width direction and axial direction, and FIG. 1, etc. define A1 side and A2 side along direction A.

[0011] In this specification, "driving connection" refers to a state in which two rotating elements are connected so as to be able to transmit a driving force (synonymous with torque), and includes a state in which the two rotating elements are connected so as to rotate integrally, or a state in which the two rotating elements are connected so as to be able to transmit a driving force via one or more transmission members. Such transmission members include various members (e.g., shafts, gear mechanisms, belts, chains, etc.) that transmit rotation at a constant speed or at variable speeds. Note that the transmission members may also include engagement devices (e.g., friction engagement devices, meshing engagement devices, etc.) that selectively transmit rotation and driving force.

[0012] In this specification, the term "power transmission path" refers to the path of power transmission from the power source (in this embodiment, a rotating electric machine 1) to the wheels, and the power transmission path is formed by multiple elements being drivingly connected from the power source to the wheels.

[0013] In this specification, the term "rotating electric machine" is used as a concept that includes motors (electric motors), generators (electric generators), and motor-generators that function as both motors and generators as needed.

[0014] Fig. 1 is a schematic top view showing a state in which a vehicle drive device 100 is mounted in a vehicle VC. Fig. 2 is a skeleton diagram showing the vehicle drive device 100 according to this embodiment. Figs. 1 and 2 schematically show the outer shape of a case 2.

[0015] The vehicle drive device 100 can be used in any vehicle having a rotating electric machine 1, such as an electric vehicle or a hybrid vehicle, and can be used in any vehicle with a drive system such as front-wheel drive or rear-wheel drive.

[0016] As shown schematically in FIGS. 1 and 2, the vehicle drive device 100 includes a rotating electric machine 1, a case 2, a pair of output members 3, a transmission mechanism 4, and a braking device 5.

[0017] The rotating electric machine 1 may be an AC rotating electric machine driven by three-phase AC. The rotating electric machine 1 is, for example, an inner rotor type. The rotating electric machine 1 has a rotor 14 that is rotatable about a first axis C1 and is disposed radially inside a stator 11 (see FIG. 2).

[0018] In this embodiment, the rotating electric machine 1 is provided to directly drive a differential gear mechanism 45 (described later). Specifically, the rotor 14 is coupled to the differential pinions 181, 182 via the differential pinion shaft 455 in a manner that the rotor 14 rotates together with the differential pinions 181, 182 and a differential pinion shaft 455 (see FIG. 5 described later) that constitute the differential gear mechanism 45. That is, the differential pinions 181, 182 revolve together with the rotor 14 about the first axis C1, and at the same time, during differential rotation, rotate about a second axis C2 that passes through the center position of the differential gear mechanism 45 and is perpendicular to the first axis C1.

[0019] The case 2 houses the rotating electric machine 1, the transmission mechanism 4, and the braking device 5. The case 2 may be formed by combining (joining) a plurality of members. The case 2 may house a portion of the output member 3. For example, the case 2 may house only a portion of one of the pair of output members 3.

[0020] One of the pair of output members 3 is drivingly connected to a first wheel W1, which is one of the pair of wheels W, and the other of the pair of output members 3 is drivingly connected to a second wheel W2, which is the other of the pair of wheels W. The output member 3 may include a drive shaft, and may be connected to the first wheel W1 and the second wheel W2 via a constant velocity joint, for example. The portion of the output member 3 that is supported by the case 2 may be in the form of an intermediate shaft.

[0021] 2, in this embodiment, the pair of output members 3 are arranged on the first axis C1 together with the rotating electric machine 1. That is, the rotating electric machine 1 and the pair of output members 3 are arranged coaxially.

[0022] The transmission mechanism 4 transmits driving force between the rotary electric machine 1 and the pair of output members 3.

[0023] The transmission mechanism 4 includes a differential gear mechanism 45 and a reduction mechanism 47 .

[0024] The differential gear mechanism 45 distributes the driving force transmitted from the rotating electric machine 1 to the pair of output members 3. In the example shown in FIG. 2, the differential gear mechanism 45 distributes the rotation of the differential pinions 181, 182 to a first side gear 451 and a second side gear 452. The differential gear mechanism 45 may be arranged coaxially with the pair of output members 3 (i.e., on the first axis C1). In this embodiment, the differential gear mechanism 45 is arranged radially inward of the rotor 14.

[0025] The speed reduction mechanism 47 is provided in the power transmission path between the differential gear mechanism 45 and the wheels W. The speed reduction mechanism 47 is optional, and may be a speed reduction mechanism using a planetary gear as shown in FIG. 2, or a speed reduction mechanism using a counter gear.

[0026] In this embodiment, the reduction gear mechanism 47 is provided in the power transmission path between the differential gear mechanism 45 and the first wheel W1, and between the differential gear mechanism 45 and the second wheel W2. That is, a pair of reduction gear mechanisms 47 are provided corresponding to the pair of output members 3. Hereinafter, when distinguishing between the left and right reduction gear mechanisms 47, the right one will be referred to as reduction gear mechanism 471 and the left one will be referred to as reduction gear mechanism 472.

[0027] The braking device 5 is provided between the rotating electric machine 1 and the pair of output members 3 in the power transmission path, and generates a braking force against the rotation of the wheels W. In this embodiment, the braking device 5 has the ability to generate a braking force large enough to appropriately stop the vehicle VC in a traveling state. Note that the magnitude of such braking force differs depending on the vehicle weight, required power performance, etc., and may be adapted for each type of vehicle.

[0028] The braking device 5 may be controlled to generate a braking force in accordance with the amount of operation of a brake pedal (not shown) by the driver. For example, the braking device 5 may constitute a brake-by-wire system. Furthermore, the braking force of the braking device 5 may be controlled in coordination with the regenerative braking by the rotating electric machine 1.

[0029] By providing such a braking device 5, it is possible to eliminate or reduce the need to separately provide a normal braking device (such as a wheel cylinder, brake rotor, or brake caliper) on the wheel W of the vehicle VC. For example, it is possible to not provide a normal braking device on the wheel W, in which case the unsprung weight can be significantly reduced. Alternatively, it is possible to provide only a braking device with lower performance than a normal braking device (such as a fail-safe drum brake), in which case the unsprung weight can also be reduced.

[0030] The braking device 5 may have any configuration and may operate in any manner. The braking device 5 may be, for example, an electrohydraulic band brake or a disc brake. In either case, the braking device 5 is housed in the case 2, and the fixing element 500 is fixed to the case 2.

[0031] In this embodiment, the braking devices 5 are provided in the power transmission path between the differential gear mechanism 45 and the first wheel W1, and between the differential gear mechanism 45 and the second wheel W2. That is, a pair of braking devices 5 are provided corresponding to a pair of output members 3. Hereinafter, when distinguishing between the left and right braking devices 5, the right one will be referred to as braking device 51 and the left one will be referred to as braking device 52.

[0032] In this case, the brake device 5 is preferably disposed between the differential gear mechanism 45 and the reduction gear mechanism 47 in the power transmission path. That is, the brake device 51 is preferably disposed between the differential gear mechanism 45 and the reduction gear mechanism 471 in the power transmission path, and the brake device 52 is preferably disposed between the differential gear mechanism 45 and the reduction gear mechanism 472 in the power transmission path. In this case, the braking torque required to stop the rotation of the wheel W can be reduced compared to when the brake device 5 is disposed between the reduction gear mechanism 47 and the wheel W in the power transmission path. This makes it possible to minimize the design value of the braking force to be generated by the brake device 5, and to reduce the size of the brake device 5.

[0033] Such a vehicle drive device 100 transmits the output torque of the rotary electric machine 1 to a pair of wheels W via a pair of output members 3, thereby allowing the vehicle VC equipped with the vehicle drive device 100 to travel. By operating the braking device 5, it is possible to reduce (adjust) the power transmitted from the rotary electric machine 1 to the pair of output members 3, or to brake the wheels W.

[0034] According to this embodiment, as described above, the braking device 5 is provided between the differential gear mechanism 45 and the left and right wheels W in the power transmission path, and therefore it is possible to brake the left and right wheels W independently of each other. Therefore, it is possible to realize functions relating to, for example, an anti-lock brake system (ABS), vehicle attitude stabilization control, and a pseudo limited slip differential (LSD) using the braking device 5. In other words, it is possible to provide the braking device 5 with a variety of functions.

[0035] Furthermore, according to this embodiment, as described above, the braking device 5 is supported by the sprung case 2, not by the unsprung wheel W. Therefore, according to this embodiment, it is possible to eliminate or miniaturize the usual unsprung braking device, and it is possible to significantly reduce the unsprung weight.

[0036] Furthermore, according to this embodiment, as described above, the braking device 5 is housed in the case 2 and is unitized with the rotating electric machine 1 and the transmission mechanism 4. This allows for an efficient arrangement, and the number of parts and weight of the vehicle drive device 100 as a whole can be reduced.

[0037] FIG. 3 is a schematic diagram showing an example of an oil supply system applicable to this embodiment.

[0038] When the braking device 5 operates hydraulically, part of the oil supplied to the braking device 5 may be used by other components of the vehicle drive system 100. That is, the braking device 5 and other components of the vehicle drive system 100 may share the same hydraulic circuit. In the example shown in FIG. 3 , the braking device 5 is connected to the electric oil pump 8 via an oil passage 81, and a part 84 to be cooled / lubricated of the vehicle drive system 100 is connected to the electric oil pump 8 via an oil passage 82. The part 84 to be cooled / lubricated may include the rotating electric machine 1 and the transmission mechanism 4. The part 84 to be cooled / lubricated may also include a bearing (not shown) or the like provided in the case 2. The oil passage 81 and the oil passage 82 may be connected via a valve or the like. The oil passages 81 and 82 may be partly or entirely formed in the case 2 by machining, or may be formed from a tubular member.

[0039] According to such an oil supply system, oil can be supplied to the braking device 5 and other components (such as the rotating electric machine 1) of the vehicle drive device 100 using a common electric oil pump 8. In this case, the number of parts can be reduced compared to when oil is supplied to the braking device 5 and other components (such as the rotating electric machine 1) of the vehicle drive device 100 using separate systems.

[0040] In a modified example, the braking device 5 may be supplied with high-pressure oil from a master cylinder (not shown) or from another hydraulic circuit. The braking devices 51 and 52 of the braking device 5 may be connected to a hydraulic circuit in such a manner that the hydraulic pressures can be controlled independently of each other. In this case, the braking device 5 can be provided with the above-mentioned ABS function and the like.

[0041] Next, another embodiment will be described with reference to FIG. 4 and subsequent figures.

[0042] FIG. 4 is a skeleton diagram showing a vehicle drive device 100A according to another embodiment.

[0043] The vehicle driving device 100A according to another embodiment differs from the vehicle driving device 100 according to the above-described embodiment in that a torque limiter 7 is added. The vehicle driving device 100A according to another embodiment also differs from the vehicle driving device 100 according to the above-described embodiment in that the speed reduction mechanism 47 is replaced with a speed reduction mechanism 47A (speed reduction mechanisms 471A, 472A). The speed reduction mechanism 47A is a stepped pinion type planetary gear.

[0044] The torque limiter 7 has a function of preventing excessive torque from acting on the brake device 5 and the like from the wheel W. The torque limiter 7 is disposed between the brake device 5 and the speed reduction mechanism 47A in the power transmission path. The torque limiter 7 may be housed in the case 2.

[0045] This embodiment also provides the same effects as the above-described embodiment.

[0046] Fig. 5 is a schematic cross-sectional view of a vehicle driving device 100A according to another embodiment. Fig. 5 shows only one side of the first axis C1. In Fig. 5, the power transmission path is indicated only on the A1 side by arrow R5, but the A2 side is also indicated in the same way.

[0047] In the example shown in FIG. 5, the brake device 5 and the torque limiter 7 are disposed between the rotating electric machine 1 and the reduction gear mechanism 47A in the direction A, utilizing dead space that is formed radially outward in the radial direction centered on the first axis C1. For example, the brake device 5 and the torque limiter 7 may be disposed radially outward of the rotor 14 of the rotating electric machine 1 (they may be disposed so as to overlap with the stator 11 when viewed in the direction of the first axis C1). In this case, utilizing the dead space can improve space efficiency. Furthermore, because the brake device 5 and the torque limiter 7 can be disposed radially outward, which is advantageous for torque, the brake device 5 and the torque limiter 7 can be made smaller.

[0048] 5, the case of differential gear mechanism 45 also serves as the shaft of rotor 14. Case 2 has center support 22, and center support 22 may have part or all of oil passage 81 described above with reference to FIG.

[0049] Although the example shown in FIG. 5 relates to the vehicle drive device 100A, the same configuration (arrangement) of the braking device 5 can be realized for the vehicle drive device 100 according to the above-described embodiment.

[0050] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments. [Explanation of symbols]

[0051] 100, 100A... Vehicle drive device, 1... Rotating electric machine, 2... Case, 14... Rotor, 45... Differential gear mechanism, 471, 471A... Reduction mechanism (first reduction mechanism), 472, 472A... Reduction mechanism (second reduction mechanism), 51... Brake device (first brake device), 52... Brake device (second brake device), 8... Electric oil pump, 81... Oil passage (first oil passage), 82... Oil passage (second oil passage), R5... Power transmission path

Claims

1. A rotating electric machine, a differential gear mechanism connected to left and right wheels and configured to transmit driving force from the rotary electric machine to the wheels; a first braking device disposed in a power transmission path between the differential gear mechanism and the left wheel, the first braking device generating a braking force against rotation of the left wheel; a second braking device disposed in a power transmission path between the differential gear mechanism and the right-side wheel, the second braking device generating a braking force against rotation of the right-side wheel; a case that supports the rotating electric machine, the differential gear mechanism, the first braking device, and the second braking device;

2. a first reduction mechanism that is disposed in a power transmission path between the differential gear mechanism and the left wheel and is supported by the case; a second reduction mechanism that is disposed in a power transmission path between the differential gear mechanism and the right wheel and is supported by the case, the first braking device is disposed between the differential gear mechanism and the first reduction mechanism in a power transmission path, 2. The vehicle drive system according to claim 1, wherein the second braking device is disposed between the differential gear mechanism and the second reduction mechanism in a power transmission path.

3. The vehicle drive device according to claim 1 , wherein the first braking device and the second braking device are disposed radially outward of the rotor of the rotating electric machine in a radial direction centered on the rotation axis of the wheel.

4. the braking device is hydraulic; An electric oil pump a first oil passage that guides oil pressure-fed from the electric oil pump to the first braking device and the second braking device; The vehicle drive device according to claim 1 , further comprising: a second oil passage within the case that guides oil pressure-fed from the electric oil pump to the rotating electric machine or the differential gear mechanism.

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