Vehicle drive device

Abstract

[Problem] To provide a vehicle drive device that can suppress the enlargement and weight increase of a support device and improve the stability of a drive unit during vehicle roll or the like. [Solution] The vehicle drive device includes: a motor (10) that generates a driving force in a vehicle having a ladder frame, a speed change mechanism (20) that changes the driving force transmitted from the motor (10), and a differential unit (14) that transmits the driving force transmitted from the speed change mechanism (20). The device further includes: a drive unit housing (25), a motor side support portion (28) that connects the drive unit housing (25) and the ladder frame (2) through two connection portions (28a, 28b) provided in a motor side end region of the drive unit housing (25), and a differential unit side support portion (29) that connects the drive unit housing (25) and the ladder frame (2) in a differential unit side end region of the drive unit housing (25). The two connection portions (28a, 28b) of the motor side support portion (28) are arranged at positions outside the differential unit side support portion (29) in the vehicle width direction.

Description

Technical Field

[0001] The present invention relates to a drive device for a vehicle. Background Art

[0002] In recent years, from the viewpoint of reducing the environmental load, development of electric trucks that are driven only by an electric motor without including an internal combustion engine has also been carried out in the field of commercial vehicles such as trucks. As a drive unit for such an electric vehicle, there is known a drive unit that includes, for example, a motor and a power transmission mechanism such as a reduction mechanism composed of a plurality of gears, so that the driving force of the motor can be transmitted to a differential gear connected to a drive wheel (Patent Document 1).

[0003] Patent Document 1: International Publication No. 2014 / 148410 Summary of the Invention

[0004] -Technical Problem to be Solved by the Invention-

[0005] When such a drive unit is installed in an electric vehicle such as a commercial vehicle, the drive unit is supported by a ladder frame or a cross member.

[0006] However, in the case of an electric truck, compared with a passenger car, the driving torque generated by the motor is large, and as a result, the torque reaction force generated in the drive unit during motor driving becomes large. Therefore, since higher reliability is required for a vehicle drive device such as a bracket, there is a possibility of causing the support device to be large-sized and heavy.

[0007] Compared with a passenger car, in the case of an electric truck, the drive unit itself is large-sized and heavy, and thus, when the vehicle rolls or pitches, the moment generated in the drive unit also becomes large. Therefore, in such a vehicle drive device, it is necessary to improve the stability of the drive unit during vehicle roll or pitch.

[0008] The present invention has been completed to solve at least a part of such problems, and an object thereof is to provide a vehicle drive device that can improve the stability of a drive unit during vehicle roll or the like while suppressing the large-sizing and heavy-weighting of a support device.

[0009] -Technical Solution for Solving the Technical Problem-

[0010] (1) The vehicle drive device according to an application example is as follows: The vehicle drive device includes a drive unit, and the drive unit includes: a motor that generates a driving force in a vehicle including a ladder frame; a speed change mechanism that changes the driving force transmitted from the motor; and a differential unit that differentially transmits the driving force transmitted from the speed change mechanism to the drive wheels of the vehicle. The vehicle drive device includes: a drive unit housing that houses at least a part of the drive unit; a motor side support portion that connects the drive unit housing and the ladder frame through two connecting portions provided in a motor side end region of the drive unit housing; and a differential unit side support portion that connects the drive unit housing and the ladder frame in a differential unit side end region of the drive unit housing. The two connecting portions of the motor side support portion are arranged at positions outside the differential unit side support portion in the vehicle width direction.

[0011] In the vehicle drive device according to the above application example, the following structure can be adopted: The two connecting portions of the motor side support portion are respectively arranged at positions outside the differential unit side support portion, that is, the differential unit side connecting portion, in the vehicle width direction. Compared with a vehicle drive device that does not adopt this structure, since the two connecting portions are located at positions far from the center of gravity of the drive unit, that is, far from the roll center, the torque generated by the roll of the drive unit acting on the connecting portions can be reduced. Therefore, the rigidity requirement for the connecting portions can be lowered. That is to say, the enlargement and high weight of the support device, that is, the connecting portions, can be suppressed, while the drive unit is supported on the ladder frame. In this way, the stability of the drive unit during vehicle roll can be improved.

[0012] (2) The vehicle drive device according to this application example can also be, on the basis of the above (1), that an imaginary line connecting the two connecting portions of the motor side support portion is parallel to the vehicle width direction. That is to say, the two connecting portions of the motor side support portion are located at the same position in the vehicle front-rear direction, so that the forces acting on the two connecting portions are equal. Therefore, the rigidity requirements for the two connecting portions are the same, and the enlargement and high weight of the connecting portions can be suppressed.

[0013] (3) The vehicle drive device according to this application example can also be, on the basis of the above (1) or (2), that the differential unit side support portion connects the drive unit housing and the ladder frame through two connecting portions provided in the differential unit side end region of the drive unit housing. Compared with the case where the differential unit side support portion is constituted by one connecting portion, by constituting the differential unit side support portion by two connecting portions, stress concentration can be avoided, the rigidity requirement for the connecting portions can be lowered, and therefore the enlargement and high weight of the connecting portions can be suppressed.

[0014] (4) The vehicle drive device according to this application example may also be such that, on the basis of (3) above, the two connecting portions of the motor side support portion and the two connecting portions of the differential side support portion are arranged such that: when viewed from above the vehicle, the imaginary lines connecting the two connecting portions of the motor side support portion and the two connecting portions of the differential side support portion form a trapezoid having the imaginary line between the two connecting portions of the motor side support portion as the lower base, and this trapezoid is line-symmetric in the vehicle width direction.

[0015] As described above, when viewed from above the vehicle, by arranging the four connecting portions, namely the connecting portions of the motor side support portion and the connecting portions of the differential side support portion, such that the imaginary lines connecting these four connecting portions form a trapezoid, it is possible to improve the roll performance of the entire vehicle. Specifically, since the vehicle and the drive device are independent mass bodies, in order to improve the roll performance of the entire vehicle, it is preferable to make the roll axis center on the drive device side as consistent as possible with the roll axis center on the vehicle side. Therefore, by arranging the two connecting portions of the above-mentioned motor side support portion and the two connecting portions of the above-mentioned differential side support portion into a trapezoid that is line-symmetric in the vehicle width direction, it is easy to make the roll axis center on the drive device side consistent with the roll axis center on the vehicle side, and the roll performance of the entire vehicle can be improved.

[0016] (5) The vehicle drive device according to this application example may also be such that, on the basis of any one of (1) to (4) above, the motor side support portion is located below the differential side support portion in the vehicle height direction. In such a structure, the shaft connecting the motor side support portion and the differential side support portion passes through the inside of the drive unit housing. Therefore, the rigidity requirement for the connecting portion of the motor side support portion can be reduced, that is to say, the enlargement and high weight of the support device, namely the connecting portion, can be suppressed, and at the same time, the drive unit can be supported on the ladder frame. In this way, the stability of the drive unit during vehicle roll can be improved.

[0017] (6) The vehicle drive device according to this application example may also be such that, on the basis of any one of (1) to (4) above, the motor side support portion is located above the differential side support portion in the vehicle height direction. In such a structure, the shaft connecting the motor side support portion and the differential side support portion passes through the inside of the drive unit housing. Therefore, the rigidity requirement for the connecting portion of the motor side support portion can be reduced, that is to say, the enlargement and high weight of the support device, namely the connecting portion, can be suppressed, and at the same time, the drive unit can be supported on the ladder frame. In this way, the stability of the drive unit during vehicle roll can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1is a schematic diagram showing a vehicle drive device according to an embodiment of the present invention when viewed from the side of the vehicle;

[0019] Figure 2 is a diagram showing the vehicle drive device when viewed from the front of the vehicle Figure 1 ;

[0020] Figure 3 is a diagram showing the vehicle drive device when viewed from above the vehicle Figure 1 ;

[0021] Figure 4 is a schematic diagram showing a vehicle drive device according to a comparative example of the present invention when viewed from the side of the vehicle;

[0022] Figure 5 is a diagram showing the vehicle drive device when viewed from the front of the vehicle Figure 4 ;

[0023] Figure 6 is a diagram showing the vehicle drive device when viewed from above the vehicle Figure 4 ;

[0024] Figure 7 is a schematic diagram showing a vehicle drive device according to another embodiment of the present invention when viewed from the side of the vehicle;

[0025] Figure 8 is a diagram showing the vehicle drive device when viewed from the front of the vehicle Figure 7 ;

[0026] Figure 9 is a diagram showing the vehicle drive device when viewed from above the vehicle Figure 7 ; DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, the structure of the embodiment of the present invention will be described in detail with reference to the drawings.

[0028] <Structures of the Embodiment>

[0029] Next, Figures 1 to 3 a brief structure of a vehicle drive device 1 according to an embodiment of the present invention will be described. Figure 1 is a schematic diagram showing a vehicle drive device 1 according to an embodiment of the present invention when viewed from the side of the vehicle. It should be noted that in Figure 1 , for ease of explaining the features, the vehicle drive device 1 is shown from a viewpoint where only the inner longitudinal beam 4R can be seen when the pair of longitudinal beams 4L and 4R described below are viewed from the side. Figure 2 is a diagram showing the vehicle drive device 1 when viewed from the front of the vehicle. Figure 3FIG. 0 is a view showing the vehicle drive device 1 as viewed from above the vehicle.

[0030] The vehicle to which the vehicle drive device 1 is applied is, for example, an electric truck including a motor, and the motor serves as a driving source for traveling. A cab and a cargo box (not shown) are mounted on the ladder frame 2. The ladder frame 2 includes a pair of left and right longitudinal beams 4L and 4R extending in the vehicle front-rear direction Y, and a plurality of cross beams 6F and 6R provided between the longitudinal beams 4L and 4R.

[0031] The pair of longitudinal beams 4L and 4R are provided at a predetermined interval in the vehicle width direction X. The cross beams 6F and 6R extend in the vehicle width direction X, and both ends of the cross beams 6F and 6R are connected to the respective longitudinal beams 4L and 4R, and a plurality of cross beams 6F and 6R are provided at a predetermined interval in the vehicle front-rear direction Y. A drive unit 8 of the vehicle is provided below the ladder frame 2.

[0032] The shape of the cross beam 6 is not particularly limited as long as it can support the drive unit 8 by means of the connecting portions 28a, 28b, 29a, and 29b described later.

[0033] The drive unit 8 includes: a motor 10 which is a driving source for traveling of the vehicle, a speed change mechanism 20 housed in a transmission 12 connected to the motor 10, and a differential device (differential portion) 14 connected to the speed change mechanism 20. The motor 10 is driven by power supplied from a battery (not shown) mounted on the vehicle to generate a driving force.

[0034] A pair of drive shafts 16L and 16R are connected to the differential device 14. The speed change mechanism 20 has a plurality of gears 20a, 20b, etc. The rotating shaft 18 of the motor 10 is connected to the input side gear 20a of the speed change mechanism 20.

[0035] The speed change mechanism 20 changes the high speed and low torque input from the motor 10 side, and can, for example, convert it into low speed and high torque and then output it. The differential device 14 includes a differential gear 24, and the output side gear 20b of the speed change mechanism 20 is connected to the differential gear 24, whereby the output decelerated by the speed change mechanism 20 is input to the differential device 14.

[0036] As described above, the driving force of the motor 10 is transmitted to the differential device 14 via the speed change mechanism 20. The differential device 14 transmits the power input from the transmission 12 side to the left and right pair of drive shafts 16L and 16R at a predetermined ratio according to the traveling state of the vehicle, and further transmits it to wheels (not shown). In this way, the vehicle travels.

[0037] Here, the motor 10, the speed change mechanism 20, and the differential device 14 are accommodated in a drive unit housing 25 that constitutes the drive unit 8, thereby integrally constituting the drive unit 8. The motor-side end region of the drive unit housing 25 is supported by two connecting portions 28a, 28b that constitute the motor-side support portion 28, and the motor-side support portion 28 is used to connect to a cross beam 6F that constitutes the ladder frame 2. Specifically, the cross beam 6F is configured to be connected to support members 7L, 7R that extend downward in the vehicle height direction Z from the cross beam 6F, and the support members 7L, 7R are connected to the connecting portions 28a, 28b. The differential portion-side end region of the drive unit housing 25 is supported by two connecting portions 29a, 29b that constitute the differential portion-side support portion 29, and the differential portion-side support portion 29 is used to connect to a cross beam 6R that constitutes the ladder frame 2. In this way, the drive unit housing 25 is connected to the connecting portions 28a, 28b, the connecting portions 29a, 29b, and the cross beams 6F, 6R, and thus the vehicle drive device 1 is supported below the ladder frame 2 in the vehicle height direction Z. It should be noted that the two connecting portions 28a, 28b of the motor-side support portion 28 are located at the same position in the vehicle front-rear direction Y. That is, the imaginary line ( Figure 3 the dash line in) is parallel to the vehicle width direction X. The two connecting portions 29a, 29b of the differential portion-side support portion 29 are located at the same position in the vehicle front-rear direction Y. That is, the imaginary line ( Figure 3 the dash line in) is parallel to the vehicle width direction X. It should be noted that in Figure 3 , the connecting portions 28a', 28b' shown by the dashed line show the connecting portions related to the comparative example described later.

[0038] The two connecting portions 28a, 28b of the motor-side support portion 28 are configured to be respectively arranged at positions outside the differential portion-side support portion 29, that is, the connecting portions 29a, 29b, in the vehicle width direction X. As Figure 3 shown, when comparing the connecting portion 28a and the connecting portion 29a, when viewed from the center of the vehicle, that is, the center between the longitudinal beams 4L and 4R, the connecting portion 28a is arranged on the side of the longitudinal beam 4L relative to the connecting portion 29a, that is, arranged outside the connecting portion 29a in the vehicle width direction X. When comparing the connecting portion 28b and the connecting portion 29b, when viewed from the center of the vehicle, that is, the center between the longitudinal beams 4L and 4R, the connecting portion 28b is arranged on the side of the longitudinal beam 4R relative to the connecting portion 29a, that is, arranged outside the connecting portion 29a in the vehicle width direction X. Therefore, when viewed from above the vehicle, the imaginary line ( Figure 3 the dash line in) connecting the connecting portions 28a, 28b, the imaginary line ( Figure 3 the dash line in) connecting the connecting portions 28a, 29a, and the imaginary line ( Figure 3the chain line in) and the imaginary line connecting the connecting portions 29a and 29b Figure 3 the chain line in) forms a trapezoid having, as a lower base, the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 and, as an upper base, the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29.

[0039] As Figure 2 shown, the connecting portions 28a and 28b of the motor-side support portion 28 are configured to be positioned below the connecting portions 29a and 29b of the differential-side support portion 29 in the vehicle height direction Z.

[0040] <Comparative Example Structure>

[0041] Next, Figures 4 to 6 a brief structure of the vehicle drive device 1' according to a comparative example of the present invention will be described. It should be noted that the same reference numerals are given to the same structures as those in the embodiments described above, and detailed descriptions thereof are omitted. A prime symbol (') is added to the reference numerals in the embodiments described above to indicate structures corresponding to those in the embodiments described above in terms of functions and the like. Figure 4 is a schematic diagram showing the vehicle drive device 1' according to a comparative example of the present invention when viewed from the side of the vehicle. It should be noted that in Figure 4 , for ease of explaining the features, the vehicle drive device 1' is shown from a viewpoint from which only the inner longitudinal beam 4R' can be seen when the pair of longitudinal beams 4L' and 4R' are viewed from the side. Figure 5 is a view showing the vehicle drive device 1' when viewed from the front of the vehicle, Figure 6 is a view showing the vehicle drive device 1' when viewed from above the vehicle.

[0042] The motor-side end region of the drive unit housing 25' is supported by two connecting portions 28a' and 28b' constituting a motor-side support portion 28' for connecting to a cross member 6F' constituting a ladder frame 2'. The differential-side end region of the drive unit housing 25' is supported by two connecting portions 29a' and 29b' constituting a differential-side support portion 29' for connecting to a cross member 6R' constituting the ladder frame 2'. In this way, the drive unit housing 25' is connected to the connecting portions 28a' and 28b', the connecting portions 29a' and 29b', and the cross members 6F' and 6R', whereby the vehicle drive device 1 is supported on the ladder frame 2'.

[0043] The two connecting portions 28a' and 28b' of the motor-side support portion 28' are configured to be respectively arranged at the same positions in the vehicle width direction X as the connecting portions 29a' and 29b' of the differential-side support portion 29'. Therefore, in Figure 6When viewed from above the vehicle, the imaginary line connecting the connecting portions 28a' and 28b' ( Figure 6 the dotted line in), the imaginary line connecting the connecting portions 28a' and 29a' ( Figure 6 the dotted line in), the imaginary line connecting the connecting portions 28b' and 29b' ( Figure 6 the dotted line in), and the imaginary line connecting the connecting portions 29a' and 29b' ( Figure 6 the dotted line in) form a rectangle with the imaginary line between the two connecting portions 28a and 28b of the motor side support portion 28 as the base and the imaginary line between the two connecting portions 29a and 29b of the differential portion side support portion 29 as the upper side.

[0044] As Figure 5 shown, the connecting portions 28a' and 28b' of the motor side support portion 28 are configured to be at the same height in the vehicle height direction Z as the connecting portions 29a' and 29b' of the differential portion side support portion 29.

[0045] <Comparison between the Embodiment and the Comparative Example>

[0046] Next, a comparison between the embodiment described above and the comparative example will be described.

[0047] When the vehicle is running, when the vehicle rolls or pitches, the torque generated by the heavy object, i.e., the drive unit 8, also becomes larger. Therefore, the torque generated by the drive unit 8 is input to the ladder frame 2 (the ladder frame 2' of the comparative example) via the connecting portions 28a and 28b (the connecting portions 28a' and 28b' of the comparative example) and the connecting portions 29a and 29b (the connecting portions 29a' and 29b' of the comparative example). From the viewpoint of running stability, it is preferable that the roll and pitch generated by the drive unit 8 and the roll and pitch generated by the vehicle are in the same phase. However, when the mounting rigidity of the connecting portions 28a and 28b (the connecting portions 28a' and 28b' of the comparative example) and the connecting portions 29a and 29b (the connecting portions 29a' and 29b' of the comparative example) is low, the phase of the roll and pitch generated by the vehicle and the roll and pitch generated by the drive unit 8 will be offset, thereby impairing the running stability. It should be noted that the so-called roll refers to the state in which the vehicle swings left and right around the axis in the vehicle longitudinal direction Y, and the so-called pitch refers to the state in which the vehicle swings back and forth around the axis in the vehicle width direction X.

[0048] Here, in the structure of the embodiment, the two connecting portions 28a and 28b of the motor side support portion 28 are configured to be respectively arranged at positions outside the differential portion side support portion 29, that is, the connecting portions 29a and 29b, in the vehicle width direction X. In contrast, in the structure of the comparative example, the two connecting portions 28a' and 28b' of the motor side support portion 28' are configured to be respectively arranged at the same positions as the differential portion side support portion 29', that is, the connecting portions 29a' and 29b', in the vehicle width direction X.

[0049] Here, the roll of the drive unit 8 caused by vehicle roll is studied. When the vehicle rolls, the drive unit 8 also rolls. However, in the drive unit housing 25 that houses the drive unit 8 according to the embodiment, the distance between the connecting portion 28a and the connecting portion 28b of the motor side support portion 28 that constitutes the heavy object, that is, the motor 10 side, in the vehicle width direction X is greater than that in the comparative example. That is to say, the connecting portions 28a and 28b are located at positions far from the center of gravity of the drive unit 8, that is, the roll center. Therefore, the torque generated by the roll of the drive unit 8 on the connecting portions 28a and 28b can be reduced. Therefore, the rigidity requirements for the connecting portions 28a and 28b can be reduced. That is to say, the enlargement and high weight of the support device, that is, the connecting portions 28a and 28b, can be suppressed, and at the same time, the drive unit 8 is supported on the ladder frame 2. In this way, the stability of the drive unit 8 when the vehicle rolls can be improved.

[0050] In the embodiment, when the vehicle rolls, in Figure 1 the view from the side, the drive unit housing 25 that houses the drive unit 8 shakes with the axis ( Figure 1 the dotted line in Figure 4 ) connecting the motor side support portion 28 and the differential portion side support portion 29 as the center. In the comparative example, the axis ( Figure 1 the dotted line in Figure 1The dash-dotted line in passes near the center of gravity of the drive unit 8. Therefore, the rigidity requirements for the connecting portions 28a and 28b can be reduced. That is to say, the enlargement and high weight of the support device, namely the connecting portions 28a and 28b, can be suppressed, while the drive unit 8 is supported on the ladder frame 2. In this way, the stability of the drive unit 8 during vehicle roll can be improved.

[0051] Moreover, when roll occurs in the drive unit 8, as described above, since the motor 10 is a component of the drive unit 8 and has a large weight, the movements of the motor-side end region and the differential-side end region of the drive unit housing 25 are different, and sometimes a large amplitude of roll may occur in the motor-side end region. At this time, when viewed from above the vehicle in , in the comparative example, the imaginary lines () connecting the connecting portions 28a' and 28b', the imaginary lines () connecting the connecting portions 28a' and 29a', the imaginary lines () connecting the connecting portions 28b' and 29b', and the imaginary lines () connecting the connecting portions 29a' and 29b' form a rectangle with the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 as the base and the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29 as the upper side. In contrast, in the embodiment-related manner, as shown in , when viewed from above the vehicle, the imaginary lines () connecting the connecting portions 28a and 28b, the imaginary lines () connecting the connecting portions 28a and 29a, the imaginary lines () connecting the connecting portions 28b and 29b, and the imaginary lines () connecting the connecting portions 29a and 29b form a trapezoid that is line-symmetrical in the vehicle width direction X (line symmetry axis: extending along the vehicle front-rear direction Y) with the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 as the lower base and the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29 as the upper base. Figure 6 When viewed from above the vehicle in , in the comparative example, the imaginary lines () connecting the connecting portions 28a' and 28b' Figure 6 the dash-dotted line in connecting the connecting portions 28a' and 29a' Figure 6 the dash-dotted line in connecting the connecting portions 28b' and 29b' Figure 6 the dash-dotted line in connecting the connecting portions 29a' and 29b' Figure 6 and the dash-dotted line in connecting the connecting portions 29a' and 29b' form a rectangle with the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 as the base and the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29 as the upper side. In contrast, in the embodiment-related manner, as shown in , when viewed from above the vehicle, the imaginary lines () connecting the connecting portions 28a and 28b, the imaginary lines () connecting the connecting portions 28a and 29a, the imaginary lines () connecting the connecting portions 28b and 29b, and the imaginary lines () connecting the connecting portions 29a and 29b form a trapezoid that is line-symmetrical in the vehicle width direction X (line symmetry axis: extending along the vehicle front-rear direction Y) with the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 as the lower base and the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29 as the upper base. Figure 3 As shown in , when viewed from above the vehicle, the imaginary line () connecting the connecting portions 28a and 28b Figure 3 the dash-dotted line in connecting the connecting portions 28a and 29a Figure 3 the dash-dotted line in connecting the connecting portions 28b and 29b Figure 3 the dash-dotted line in connecting the connecting portions 29a and 29b Figure 3 and the dash-dotted line in connecting the connecting portions 29a and 29b form a trapezoid that is line-symmetrical in the vehicle width direction X (line symmetry axis: extending along the vehicle front-rear direction Y) with the imaginary line between the two connecting portions 28a and 28b of the motor-side support portion 28 as the lower base and the imaginary line between the two connecting portions 29a and 29b of the differential-side support portion 29 as the upper base.

[0052] As described above, when observing from above the vehicle, by arranging the four connecting portions, namely the connecting portions 28a and 28b of the motor side support portion 28 and the connecting portions 29a and 29b of the differential portion side support portion 29, such that the imaginary line connecting these four connecting portions forms a trapezoid, the roll performance of the entire vehicle can be improved. Specifically, since the vehicle and the drive device are independent mass bodies, in order to improve the roll performance of the entire vehicle, it is preferable to make the roll axis center on the drive device side coincide with the roll axis center on the vehicle side as much as possible. Therefore, as Figure 3 shown, the four connecting portions are arranged such that the lengths L in the vehicle width direction X increased at the connecting portions 28a and 28b are equal compared to the comparative example. Thus, it is easy to make the roll axis center on the drive device side coincide with the roll axis center on the vehicle side, and the roll performance of the entire vehicle can be improved.

[0053] Next, the pitching of the drive unit 8 caused by the pitching of the vehicle is studied. When the vehicle pitches, the drive unit 8 also pitches. However, in the drive unit housing 25 that houses the drive unit 8 according to the embodiment, the distance in the vehicle longitudinal direction Y between the connecting portions 28a and 28b of the motor side support portion 28 that constitutes the heavy object, i.e., the motor 10 side, and the connecting portions 29a and 29b of the differential portion side support portion 29 is greater than that in the comparative example. That is to say, the connecting portions 28a and 28b are located at positions far from the center of gravity of the drive unit 8, i.e., the pitching center. Therefore, the torque generated by the pitching of the drive unit 8 acting on the connecting portions 28a and 28b can be reduced. As a result, the requirement for the rigidity of the connecting portions 28a and 28b can be lowered. That is to say, the enlargement and high weight of the support device, i.e., the connecting portions 28a and 28b, can be suppressed, and at the same time, the drive unit 8 is supported on the ladder frame 2. In this way, the stability of the drive unit 8 when the vehicle pitches can be improved.

[0054] Next, the torque reaction force when the motor 10 is excited is studied. When the motor 10 is excited, the rotating shaft 18 rotates, and this rotation is transmitted to the differential gear 24 of the differential device 14 via the speed change mechanism 20, and the wheels are rotated via a pair of drive shafts 16L and 16R. At this time, a rotational torque centered on the drive shafts 16L and 16R is generated in the drive unit 8 by virtue of the reaction force from the road surface against the rotation of the wheels. Here, the distance between the shafts of the drive shafts 16L and 16R and the connecting portions 28a and 28b of the motor side support portion 28 according to the embodiment is larger than the distance between the drive shafts 16L and 16R and the connecting portions 28a' and 28b' of the motor side support portion 28' of the comparative example. That is to say, the rotational torque applied to the drive unit 8 can be supported at a farther position. Therefore, it is possible to suppress the enlargement and high weight of the connecting portions 28a and 28b of the motor side support portion 28 according to the embodiment, and at the same time support the drive unit 8 on the ladder frame 2, thereby improving the stability of the drive unit 8 when the motor 10 is driven.

[0055] As described above, the vehicle drive device 1 of the present embodiment includes a drive unit, which includes: a motor 10 that generates a driving force in a vehicle including a ladder frame 2; a speed change mechanism 20 that changes the driving force transmitted from the motor 10; and a differential device 14 that differentially transmits the driving force transmitted from the speed change mechanism 20 to the drive wheels of the vehicle. The vehicle drive device can adopt the following structure: it includes: a drive unit housing 25 that houses at least a part of the drive unit 8; a motor side support portion 28 that connects the drive unit housing 25 and the ladder frame 2 through two connecting portions provided in the motor side end region of the drive unit housing 25; and a differential portion side support portion 29 that connects the drive unit housing 25 and the ladder frame 2 in the differential portion side end region of the drive unit housing 25. The two connecting portions 28a and 28b of the motor side support portion 28 are arranged at positions outside the differential portion side support portion 29 in the vehicle width direction.

[0056] Therefore, compared with a vehicle drive device that does not adopt this structure, the two connecting portions 28a and 28b are located at positions far from the center of gravity of the drive unit 8, that is, far from the roll center. Therefore, the torque generated by the roll of the drive unit 8 acting on the connecting portions 28a and 28b can be reduced. Therefore, the rigidity requirements for the connecting portions 28a and 28b can be lowered. That is to say, it is possible to suppress the enlargement and high weight of the support device, that is, the connecting portion, and at the same time support the drive unit 8 on the ladder frame 2. In this way, the stability of the drive unit 8 during vehicle roll can be improved.

[0057] The two connecting portions 28a and 28b of the motor side support portion are located at the same position in the vehicle longitudinal direction Y, and the imaginary line connecting the two connecting portions 28a and 28b of the motor side support portion 28 is parallel to the vehicle width direction X. Therefore, the forces applied to the two connecting portions 28a and 28b can be made equal, and thus the same rigidity requirements are imposed on the two connecting portions 28a and 28b, and the enlargement and high weight of the connecting portions 28a and 28b can be suppressed.

[0058] The differential side support portion 29 connects the drive unit housing 25 and the cross member 6R of the ladder frame 2 through two connecting portions 29a and 29b provided in the differential side end region of the drive unit housing 25. Therefore, compared with the case where the differential side support portion is constituted by one connecting portion, by constituting the differential side support portion 29 by two connecting portions 29a and 29b, stress concentration can be avoided, the rigidity requirements for the connecting portions 29a and 29b can be reduced, and the enlargement and high weight of the connecting portions 29a and 29b can be suppressed.

[0059] When viewed from above the vehicle, the imaginary lines of the two connecting portions 28a and 28b of the motor side support portion 28 and the two connecting portions 29a and 29b of the differential side support portion 29 are arranged in a trapezoid with the imaginary line between the two connecting portions of the motor side support portion 28 as the lower base, and this trapezoid is line-symmetric in the vehicle width direction.

[0060] As described above, when viewed from above the vehicle, by arranging the four connecting portions, namely the connecting portions 28a and 28b of the motor side support portion 28 and the connecting portions 29a and 29b of the differential side support portion 29, such that the imaginary lines connecting these four connecting portions form a trapezoid, the roll performance of the entire vehicle can be improved. Specifically, since the vehicle and the drive device are independent mass bodies, in order to improve the roll performance of the entire vehicle, it is preferable to make the roll axis center on the drive device side as consistent as possible with the roll axis center on the vehicle side. Therefore, as Figure 3 shown, the lengths L in the vehicle width direction X increased at the connecting portions 28a and 28b are made equal compared with the comparative example, whereby it is easy to make the roll axis center on the drive device side consistent with the roll axis center on the vehicle side, and the roll performance of the entire vehicle can be improved.

[0061] The motor-side support portion 28 is located below the differential-side support portion 29 in the vehicle height direction Z. Therefore, the shaft connecting the motor-side support portion 28 and the differential-side support portion 29 passes through the inside of the drive unit housing 25. Accordingly, the rigidity requirements for the connecting portions 28a, 28b of the motor-side support portion 28 can be reduced. That is to say, it is possible to suppress the enlargement and high weight of the support device, namely the connecting portions 28a, 28b. At the same time, the drive unit is supported on the ladder frame 2 via the support members 7L, 7R extending from the cross member 6F. In this way, the stability of the drive unit 8 during vehicle roll or the like can be improved.

[0062] It should be noted that, in the above embodiment, the differential-side support portion 29 is composed of two connecting portions 29a, 29b. However, the connecting portion 29a and the connecting portion 29b may be combined into one connecting portion to serve as the differential-side support portion 29.

[0063] <Structure of Other Embodiments>

[0064] Next, Figures 7 to 9 A brief structure of the vehicle drive device 1” according to another embodiment of the present invention will be described. It should be noted that the same reference numerals are assigned to the same structures as those in the previously described embodiment, and the detailed description thereof is omitted. A triple prime (””) is added to the reference numerals in the previously described embodiment to indicate the structures corresponding to those in the previously described embodiment in terms of functions and the like. Figure 7 is a schematic diagram showing the vehicle drive device 1” according to another embodiment of the present invention when viewed from the side of the vehicle. It should be noted that Figure 7 in, for the convenience of explaining the features, the vehicle drive device 1” is shown from a viewpoint where only the inner longitudinal beam 4R” can be seen when the pair of longitudinal beams 4L”, 4R” are viewed in side elevation. Figure 8 is a view showing the vehicle drive device 1” when viewed from the front of the vehicle. Figure 9 is a view showing the vehicle drive device 1” when viewed from above the vehicle.

[0065] The motor-side end region of the drive unit housing 25” is supported by two connecting portions 28a”, 28b” that form the motor-side support portion 28”. The motor-side support portion 28” is used to connect to the cross member 6F” that forms the ladder frame 2”. Specifically, the cross member 6F” is configured to be connected to support members 7L”, 7R” that extend upward in the vehicle height direction Z from the cross member 6F”. The support members 7L”, 7R” are connected to the connecting portions 28a”, 28b”. The differential portion side end region of the drive unit housing 25” is supported by two connecting portions 29a”, 29b” that form the differential portion side support portion 29”. The differential portion side support portion 29” is used to connect to the cross member 6R” that forms the ladder frame 2”. In this way, the drive unit housing 25” is connected to the connecting portions 28a”, 28b”, the connecting portions 29a”, 29b”, and the cross members 6F”, 6R”. Thereby, the vehicle drive device 1” is supported above the ladder frame 2” in the vehicle height direction Z.

[0066] The two connecting portions 28a”, 28b” of the motor-side support portion 28” are configured to be respectively arranged at positions outside the differential portion side support portion 29”, that is, the connecting portions 29a”, 29b”, in the vehicle width direction X. As Figure 9 shown, when comparing the connecting portion 28a” and the connecting portion 29a”, when viewed from the center of the vehicle, that is, the center of the longitudinal beams 4L” and 4R”, the connecting portion 28a” is arranged on the side of the longitudinal beam 4L” relative to the connecting portion 29a”, that is, arranged outside the connecting portion 29a” in the vehicle width direction X. Similarly, when comparing the connecting portion 28b” and the connecting portion 29b”, when viewed from the center of the vehicle, that is, the center of the longitudinal beams 4L” and 4R”, the connecting portion 28b” is arranged on the side of the longitudinal beam 4R” relative to the connecting portion 29a”, that is, arranged outside the connecting portion 29a” in the vehicle width direction X. Therefore, when viewed from above the vehicle, the imaginary lines ( Figure 9 the dotted lines in) connecting the connecting portions 28a”, 28b”, the imaginary lines ( Figure 9 the dotted lines in) connecting the connecting portions 28a”, 29a”, the imaginary lines ( Figure 9 the dotted lines in) connecting the connecting portions 28b”, 29b”, and the imaginary lines ( Figure 9 the dotted lines in) connecting the connecting portions 29a”, 29b” form a trapezoid with the imaginary line between the two connecting portions 28a”, 28b” of the motor-side support portion 28” as the lower base and the imaginary line between the two connecting portions 29a”, 29b” of the differential portion side support portion 29” as the upper base.

[0067] As Figure 8 shown, the connecting portions 28a”, 28b” of the motor-side support portion 28” are configured to be located above the connecting portions 28a”, 28b” of the differential portion side support portion 29” in the vehicle height direction Z.

[0068] As described above, the vehicle drive device 1” according to other embodiments of the present invention is configured such that the drive unit 8 is located above the ladder frame 2” in the vehicle height direction Z. As Figure 7 , Figure 8 shown, in the vehicle drive device 1” according to other embodiments of the present invention, the motor side support portion 28” is located above the differential side support portion 29” in the vehicle height direction Z. In the embodiment, when the vehicle rolls, in Figure 7 the view from the side, the drive unit housing 25” that houses the drive unit 8 sways about the axis connecting the motor side support portion 28” and the differential side support portion 29”. Since the motor side support portion 28” is located above the differential side support portion 29” in the vehicle height direction Z, the axis ( Figure 7 the dotted line in ) connecting the motor side support portion 28” and the differential side support portion 29” passes through the inside of the drive unit housing 25”. The motor side support portion 28” is located near the center of gravity of the heavy object, i.e., the motor 10, in the structure of the drive unit 8. That is, the axis ( Figure 7 the dotted line in ) connecting the motor side support portion 28” and the differential side support portion 29” passes through near the center of gravity of the drive unit 8. Therefore, the rigidity requirements for the connecting portions 28a” and 28b” can be reduced. That is to say, the enlargement and high weight of the support device, i.e., the connecting portions 28a” and 28b”, can be suppressed, and at the same time, the drive unit 8 is supported on the ladder frame 2”. In this way, even when the structure in which the drive unit 8 is located above the ladder frame 2” in the vehicle height direction Z is adopted, the stability of the drive unit 8 when the vehicle rolls can be improved.

[0069] It should be noted that in the above embodiment, an electric truck having only the motor 10 as a driving source for traveling is taken as an example for description, but the vehicle drive device 1 can also be applied to a hybrid electric truck that uses an internal combustion engine and the motor 10 in combination. The vehicle drive device 1 can be applied not only to electric trucks but also to all commercial vehicles including the motor 10.

[0070] In the above embodiment, the drive unit housing 25 houses the drive unit 8, but it may also be configured to house only a part of the drive unit 8.

[0071] In the above embodiment, the drive unit housing 25 houses the drive unit 8, but it may also be configured to house only a part of the drive unit 8.

[0072] In the above embodiment, the drive unit 8 having the speed change mechanism 20 is taken as an example for description, but the drive unit 8 according to the present invention may also be a drive unit including a multi-stage speed change mechanism.

[0073] As described above, embodiments of the present invention have been described, but the present invention can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalents.

[0074] 1 Vehicle drive device

[0075] 2 Trapezoidal frame

[0076] 4L, 4R longitudinal beams

[0077] 6F, 6R cross beams

[0078] 7L, 7R support members

[0079] 8 Drive unit

[0080] 10 Motor

[0081] 14 Differential device

[0082] 16L, 16R drive shafts

[0083] 18 Rotating shaft

[0084] 20 Transmission mechanism

[0085] 20a, 20b transmission gears

[0086] 24 Differential gears

[0087] 25 Drive unit housing

[0088] 28 Motor side support portion

[0089] 28a, 28b connecting portions

[0090] 29 Differential portion side support portion

[0091] 29a, 29b connecting portions

Claims

1. A drive device for a vehicle, which includes a drive unit, and the drive unit includes: A motor that generates a driving force in a vehicle including a trapezoidal frame; A speed change mechanism that changes the driving force transmitted from the motor; And a differential unit that distributes and transmits the driving force transmitted from the speed change mechanism to the drive wheels of the vehicle, characterized in that: The vehicle drive device includes: A drive unit housing that houses at least a part of the drive unit; A motor side support portion that connects the drive unit housing and the trapezoidal frame through two connecting portions provided in a motor side end region of the drive unit housing; and A differential unit side support portion that connects the drive unit housing and the trapezoidal frame in a differential unit side end region of the drive unit housing, The two connecting portions of the motor side support portion are arranged at positions outside the differential unit side support portion in the vehicle width direction, The differential unit side support portion connects the drive unit housing and the trapezoidal frame through two connecting portions provided in the differential unit side end region of the drive unit housing, The two connecting portions of the motor side support portion and the two connecting portions of the differential unit side support portion are arranged such that: when viewed from above the vehicle, an imaginary line connecting the two connecting portions of the motor side support portion and the two connecting portions of the differential unit side support portion forms a trapezoid having an imaginary line between the two connecting portions of the motor side support portion as the lower base, and the trapezoid is line-symmetric in the vehicle width direction.

2. The vehicle drive device according to claim 1, characterized in that: The imaginary line connecting the two connecting portions of the motor side support portion is parallel to the vehicle width direction.

3. The vehicle drive device according to claim 1 or 2, characterized in that: The motor side support portion is located at a position lower than the differential unit side support portion in the vehicle height direction.

4. The vehicle drive device according to claim 1 or 2, characterized in that: The motor side support portion is located at a position higher than the differential unit side support portion in the vehicle height direction.

Images